Caribbean
Environment
Programme

United Nations Environment Programme

Proceedings of the Workshop on Adopting, Applying and
Operating Environmentally Sound Technologies for
Domestic and Industrial Wastewater Treatment for the
Wider Caribbean Region

CEP Technical Report No. 43
1998

Note: The designations employed and the presentation of the material in this document do not imply the expression

of any opinion whatsoever on the part of UNEP concerning the legal status of any State, Territory, city or area, or

its authorities, or concerning the delimitation of their frontiers or boundaries.

For bibliographic purposes the printed version of this document may be cited as:

UNEP: Proceedings of the Workshop on Adopting, Applying and Operating Environmentally

Sound Technologies for Domestic and Industrial Wastewater Treatment for the Wider Caribbean
Region.

CEP Technical Report No. 43. UNEP Caribbean Environment Programme, Kingston, 1998.

FOREWORD
The enhancement of awareness and the development of the capabilities of managers and decision
makers at a regional and national level are among the program priorities of UNEP's International
Environmental Technology Centre (IETC) and the Regional Coordinating Unit of the Caribbean
Environment Programme (CAR/RCU). In particular, knowledge of the issues in adoption, application
and operation of environmentally sound technologies (ESTs) has become essential in planning the
sustainable use of natural resources and the reduction of environmental impacts from human
activities like waste.
IETC has already undertaken two pilot workshops on Adopting, Applying and Operating
Environmentally Sound Technologies in different parts of the world. The first one was held in
September 1996 in Dresden, Germany and focussed on Urban and Freshwater Resources. The second
was in December 1997 at Murdoch University in Australia and focussed on Urban Management.
The Workshop for the Wider Caribbean Region, held in Montego Bay, Jamaica, November 1998, has
its origins in the Dresden Workshop, where participants from the Caribbean and the Atlantic Region
elaborated proposals for regional follow-up. In the Dresden Workshop, training modules were
prepared by Murdoch University encompassing presentations from specialists on industrial and
domestic wastewater treatment as well as country representatives. Presentations during the
workshops addressed different key issues such as information systems and databases related to ESTs,
alternative technological approaches to treatment, technological solutions and innovations and the
identification of future actions by the countries.
The Montego Bay Workshop gathered national experts from 20 Technical Focal Points in the Wider
Caribbean Region plus a number of experts on wastewater treatment, private enterprises, members of
the US Peace Corps, and representatives from various international agencies such as the US Agency
for International Development, European Union, Caribbean Environmental Health Institute and
German Technical Cooperation (GTZ). Also, as part of IETC's and CEP's support to the Program for
Small Island Developing States (SIDS) a government official from the island of Cape Verde in the
Atlantic was invited to participate and share experiences with experts from the region.
The Workshop provided experts from Governments in the Region with the basic concepts related to
Adopting, Applying and Operating Environmentally Sound Technologies (ESTs). This background
in ESTs was supplemented with information on the latest technological alternatives for the treatment
of industrial and domestic wastewater. The IETC and UNEP-CAR/RCU believe that the Workshop
has provided a sound basis for ESTs to be considered in the planning process when governments are
identifying and selecting technologies to suit their specific needs.

Lilia Casanova Nelson Andrade Colmenares
Deputy Director and OIC Co-ordinator
IETC UNEP-CAR/RCU

EDITORIAL

Communities in the Wider Caribbean Region have a strong desire to improve their environment.
This desire was clearly expressed in the country presentations given by delegates to the UNEP
Workshop on Adopting, Applying and Operating Environmentally Sound Technologies for
Domestic and Industrial Wastewater Treatment.
There was as well a general realization that the solution to environmental problems facing the
marine environment in the region lies with communities themselves, and that the future will be
shaped by steps and actions taken within the region. Furthermore a significant contribution can
be made by the country delegates attending the workshop. It was therefore a pleasant and
rewarding experience for the group from Murdoch University to facilitate the workshop to help
define the existing problems more clearly, to consider technologies that have been developed
within the region and elsewhere, and to assist country delegates with developing strategies that
they can implement in the short, medium and long term in their countries.
The process described above began quite some time before the workshop with countries in the
region identifying national experts to send as delegates to the workshop, and with the preparation
of country papers by the delegates. At about the same time, specialists familiar with the
environmental problems faced by developing nations came to present technologies that can
provide solutions to the problems that were identified by country representatives.
From the country papers (Part 2 in this book) it becomes obvious that the existing situation in the
Wider Caribbean Region is generally similar, differing only in the degree of the problems
experienced. There is a lack of collection and treatment of wastewater, with much of it ending in
the marine environment and impacting negatively on it. The marine environment is a major
tourist attraction that needs to be protected to ensure its long term viability. Where there is
collection and treatment of wastewater, the facilities are not generally operated or maintained to
specification. Lack of resources, personnel, training of personnel, institutional arrangement or
enforcement of legislation were mentioned as possible causes. While there is cultural and
economic diversity in the Wider Caribbean it appears that the experience in the region is not very
different from the experience elsewhere as illustrated by the case study of Cape Verde, an island
located west of the continent of Africa.
Invited speakers presented papers (Part 1 of this book) on technologies that have been
successfully used in both developed and developing countries. We think this is an important
point to make because technologies that are proposed for developing countries should not be
seen as being appropriate only for the latter. We are very pleased to see papers from the United
States, Canada, South America and Australia giving examples where technologies have been
demonstrated to be equally applicable in both, having regard to long term sustainability.
While papers were presented on specific technologies for wastewater management, these were
placed in a wider context by other presentations. The other presentations covered subjects
ranging from technology choice and sustainable development, the basic scientific understanding
required to assist with the choice of technology, impact of waste disposal on the marine

environment, to the development of a protocol to control pollution of the marine environment of
the Wider Caribbean Region developed by countries in the region.
Two major benefits of workshops are the networking of delegates and the exchange of ideas that
make the contribution of individual papers greater than their sum. We are pleased to report that
these two were very evident during the workshop. Presenters from outside and within the region
were questioned about their ideas and their applicability for the region. Sources of information
were made available and a number of these were formally presented.
A significant outcome of the workshop is the deliberation of delegates on what steps they can
take in the short, medium and long term to assist with efforts to protect the marine environment
in the region from land based discharges of wastewater. These were formalized on the last day of
the workshop through discussion groups summarising the existing conditions, current
technologies and future options.
We trust that the networking achieved at the workshop and the outcome of the workshop, which
includes this publication containing proceedings of the workshop, will contribute towards
achieving a better marine environment in the Wider Caribbean Region. We would like to suggest
that we follow up the recommendations made at the workshop after a year or two to assess where
steps have been taken and improvements made, and what further steps are required to achieve the
goal.
We commend the initiative of UNEP IETC and UNEP - CAR/RCU and invite readers to
evaluate the papers for application in their specific community, country or region. We would also
like to welcome comments and suggestions on papers presented at the workshop and on the
workshop itself.

Goen HoDirector, Institute for Environmental Science
Murdoch University
Perth, Australia
February 1999

PART 1

INVITED PAPERS

Technology Choice and Sustainable Development
Dr Martin Anda
Institute for Environmental Science, Murdoch University, South Street, Murdoch WA 6150, Australia
Tel: (61-8) 9360-6123, Fax: (61-8) 9310-4997, Email: anda@essun1.murdoch.edu.au

The Concept of Sustainable Development
In recent years, the pursuit of Sustainable Development has become a goal common to
environmentalists, economists, development theorists, governments, and even many
industrialists. This broad-based concern for both environment and development is part of a
second wave of modern environmentalism (Beder 1993, p.xi).
The first wave of modern environmentalism peaked in the 1960's and early 1970's. During these
years a significant number of scientists began to express their concern for environmental issues
such as the effects of pollution and the depletion of non-renewable natural resources. There was
also a rapid increase in public concern for the welfare of the natural environment. Nature
conservation organisations expanded their interests to include environmental issues, and new
organisations and societies were formed specifically to draw attention to environmental issues
(e.g. Greenpeace formed in 1971).
Environmentalism in the 1960's and early 1970's was different to environmentalism today in that
it had very little support from mainstream economists and industrialists. It was also much more
antagonistic towards industry, and the western capitalist ideal of pursuing never-ending
economic growth. First wave environmentalists voiced concern that population growth and the
growth of industry could not be sustained indefinitely. Many argued that a global ecological
crisis was imminent, and the pursuit of economic and industrial development was held to be
responsible (e.g. Meadows et al. 1972). At the time, governments were reluctant to acknowledge
the presence of global environmental problems, or to recognise the possibility of a global
ecological crisis. However, many governments in wealthier nations (including Australia)
responded to community pressure and introduced clean air acts, clean water acts, and other forms
of environmental legislation.
The first wave of modern environmentalism lost its momentum in the late 1970's and early
1980's, largely because a number of writers began to argue that a global environmental crisis was
just doomsday fantasy (see Beder 1993, Adams 1990). These views were quite popular amongst
some leading members of the governments of affluent industrialised nations. Governments which
had previously responded to community pressure to place environmental restrictions on industry,
bowed to growing pressure from both industry and the public for economic growth.
Governments became less enthusiastic about getting involved in the introduction of new
environmental legislation, and in some cases they became reluctant to enforce existing
legislation.
The second wave of modern environmentalism began in the late 1980's. One of the events that
helped this second wave along was the emergence of convincing scientific evidence about the

build-up of greenhouse gases in the atmosphere, and convincing evidence that the ozone layer
was being depleted. Another significant event was the release of The Brundtland Report1 in 1987
by the United Nations World Commission on Environment and Development. In the Brundtland
Report the World Commission argued that the world was in urgent need of both environmental
protection and economic development. Thus, it proclaimed, sustainable forms of economic
development needed to be encouraged. The World Commission defined Sustainable
Development as:
"development that meets the needs of the present
without compromising the ability of future
generations to meet their own needs."
The Brundtland Report was not the first publication to suggest that development needed to be
sustainable, or the first to give a definition of sustainable development.2. However, it was much
more influential than previous documents because the timing of its release, and also because of
the prominent position of its authors in the international political arena. At the time of the release
of the Brundtland Report Sustainable Development was approved in the UN General Assembly
and also accepted as a national goal by the governments of 100 nations (Beder 1993, p. xiii).
Critics of the Brundtland Report have argued that the Brundtland Report's definition of
Sustainable Development is very loose, and that this has allowed different interest groups to
interpret the definition in ways that suit their own specific goals. They argue that whilst interest
groups may all agree that the environment must be protected, they often have different ideas
about which bits of the environment should be protected, different ideas about how it should be
protected, and different ideas about what development is. In other words, although interest
groups may all agree that the pursuit of Sustainable Development is important and necessary,
they often disagree about how it should be pursued.
This became very apparent in 1990 when the Australian Commonwealth Government set up a
number of working groups to formulate a National Strategy for Ecologically Sustainable
Development. The working groups were to study how Sustainable Development could be applied
to nine industry sectors that were thought to have a significant impact on natural resources.
These sectors were: agriculture; energy use; energy production; transport; mining; fisheries;
forest use; tourism; manufacturing.
The working group members consisted of representatives from government, industry, unions,
consumer/social welfare organisations, and conservation groups. Summaries of the working
group's findings were released in 1992. Some representatives from conservation and
environmental organisations were not satisfied by the way the working groups operated. They
felt that intersectorial issues (the issues that crossed sector boundaries) were not dealt with

1 The Brundtland Report was entitled "Our Common Future" but it is commonly referred to as the Brundtland
Report after the World Commission's chairperson Gro Harlem Brundtland. Commonly referred to as the Brundtland
Report after the World Commission's chairperson Gro Harlem Brundtland.

2 Other writers and committees had given definitions for Sustainable Development years earlier eg. the UN
Conference on the Human Environment held in Stockholm in 1972, and the World Conservation Strategy published
in 1980.

properly. Other environmentalists argued that contentious issues and recommendations were left
out in the effort to reach consensus, and that the policy options and recommendations that
appeared in the final reports were conservative and aimed at slow incremental change rather than
the more radical dramatic change which they felt was necessary.
Environmentalists have leveled similar criticism at the United Nations Conference on
Environment and Development which was held in Rio de Janeiro in June 1992. Agenda 21, a
program of environmental action for the 21st Century which the UN hopes will be undertaken by
all nations, was criticised as being weak and without strong statements on important but
contentious issues such as the role of trans-national corporations, population control, and
consumption in affluent nations.
The Brundtland Report's version of Sustainable Development, which is the basis of the
Australian Commonwealth Government's National Strategy, has also been criticised by those in
the field of Development Studies. Some writers specialising in development issues have argued
that the Brundtland Report is essentially just a reformed, greener version of
"developmentalism"3. They argue that the Brundtland Report looks at the environment from the
perspective of affluent industrialised nations (which they refer to as the core). Sustainable
Development, in their opinion, should look at the environment from the perspective of poor
Third World communities (the periphery). Thus, rather than primarily focusing on reducing the
environmental impact of existing economic practices, affluent industrialised nations should look
at changing existing economic practices in order to ensure that the poor have a secure and
sustainable livelihood (Adams 1990, p.5, 198; Chambers 1987).
Zethoven (1991) defined three positions present in the Sustainable Development debate: shallow,
intermediate and deep sustainable development. The first assumed that natural and human-made
assets could be substituted while the other two couldn't. The Business Council of Australia and
the Australian Government, for example, fitted the 'shallow' position with their continued
support for indiscriminate economic growth even with the loss of "unimportant species". The
ecologically sustainable development package brokered by the Australian Government between
industry and the mainstream conservation organisations on this shallow basis resulted in
Greenpeace walking out of these negotiations (Beder, 1994). The Brundtland Report espoused an
'intermediate' position which would accommodate growth in developing countries to achieve a
sustainable livelihood security while growth in the industrialised world was to be curbed. Many
environmentalists fit the 'deep' position of sustainable development and interestingly this is
perhaps the position applicable to Fourth World communities. Within a framework of 'deep'
sustainable development local communities, for example, remote indigenous communities, are
able to undertake limited and finite growth to remedy the disadvantage they suffer within an
industrialised nation.
Beder (1994, p39) called for a 'third wave' of environmentalism which would "transcend both the
protest [first wave] and consensus [second wave] approaches of recent decades."

3 The term "developmentalism" is used to describe the view that all countries should progress down the (linear) path
towards modernisation, and that progress the path can be measured in terms of economic growth and the rate at
which modern technology is adopted.

References on Sustainable Development
Adams, W.M. (1990) Green development: Environment and sustainability in the Third World.
Routledge, London pp. 14-65.
Adams, W.M. (1993) Sustainable Development & the Greening of Development Theory, in F.J.
Schuurman (ed), Beyond the Impasse, Zed Books, pp. 207-222.
Beder, S. (1993) The Nature of Sustainable Development. Scribe Publications, Newham,
Australia. pp. 3-8.
Beder S (1994), Revoltin' Developments: The politics of sustainable development, Arena
Magazine, June/July, pp. 37-39.
Bookchin, M. (1983) An open letter to the ecological movement. RAIN, Oct/Nov.
Brundtland, H. (1987) Our common future. Oxford University Press, Oxford (for the World
Commission on Environment and Development). pp. 45-65
Chambers, R. (1987) Sustainable Rural Livelihoods: A Strategy For People, Environment and
Development. Overview paper for Only One Earth; Conference on Sustainable Development,
IIED, London, 1987
Commonwealth of Australia (1992) National strategy for Ecologically Sustainable Development.
December, AGPS, Canberra. pp. 6-19 (Introduction)
Meadows, D., Randers, J., Behrens, W.W. (1972) The Limits to Growth. Universe Books, New
York.
Sachs, W. (1992) Whose environment? New Internationalist 232, 20-22.
World Commission on Environment & Development (1995), Towards Sustainable Development,
in Conca et. al. (eds), Green Planet Blues, Westview Press, pp. 211-221.
Zethoven I (1991), Sustainable Development - a critique of perspectives, in Immigration,
Population and Sustainable Environment, Smith J W (ed), Flinders University Press, Adelaide.

Technology for Sustainable Development
As explored in the previous section, there are a range of physical and social factors which are
going to determine whether economic activities are sustainable or not. An important element in
these physical and social dimensions of sustainability is the choice of technology and whether or
not the technology is appropriate in a given set of circumstances.

The concept of Appropriate Technology (AT) was first synthesised by E.F. Schumacher and
expounded in his landmark work Small is Beautiful. A definition of AT which accords closely
with Schumacher's original ideas is that of: "a technology tailored to fit the psychosocial and
biophysical context prevailing in a particular location and period" (Willoughby, 1990).
As with sustainable development, the subject of AT is an enormous one in itself. The term AT
has been widely and loosely used to cover a multitude of concepts depending on the particular
emphasis and agenda of the author. Some have referred to it in a derogatory way, calling it a
"bandwagon" term covering everything from philosophical approaches to technology, ideologies,
political-economic critiques, social movements, economic development strategies, particular
types of technical hardware, and 'anti-technology' activities (see Willoughby, 1990, pp. 16-17).
Despite these criticisms, the idea of AT remains central in the pursuit of sustainable development
in affluent and less affluent countries, and is a key concept in the evolution of new
environmental technologies.
The most comprehensive discussion of the philosophical issues concerning AT can be found in
Willoughby (1990). What is important to recognise here is that:
� it is indeed possible to choose technologies which are inappropriate in the prevailing
physical and social circumstances (many examples are provided in the essential
readings), and;
� it has become crucial to give a great deal more thought to the appropriateness of
technologies because:
a. if this is not done then even the technical task to which the technology is directed
will not be accomplished and
b. particular technologies bring with them underlying structures and assumptions
which may be destructive to the society in which they are introduced.
Thus, if development is to become more sustainable, it is important to assess technologies on a
number of different criteria before adopting them. These criteria cover the technical, social and
economic requirements of the specific situation. This applies as much to so-called 'environmental
technologies', as it does to more mainstream technological approaches.

References on Technology Choice
Azelvandre, J.P., (1994) Technology Choices For A Sustainable Future: Some Conditions and
Criteria For Appropriate Technology. Ecotech '94 Papers and Discussions.
McRobie G (1991), Ideas into Action - the early years, Appropriate Technology, 18, 2: 1-4, IT
Publications, London.
Mitchell, R.J. (1980) Experiences in appropriate technology. The Canadian Hunger Foundation,
Ottawa, Canada.

Sachs, W. (1992) Technology as a Trojan horse New Internationalist 232, 12-14
Smillie I (1991), Mastering the Machine: Poverty, aid & technology, IT Publications, London.
Willoughby, K. (1990) Technology choice: A critique of the appropriate technology movement.
Westview Press, Intermediate Technologies Publications, London.

Land-Based Sources of Marine Pollution
In the Wider Caribbean Region
A Protocol for Action
Tim Kasten
Programme Officer, UNEP-CAR/RCU, 14-20 Port Royal Street, Kingston, Jamaica
Tel: (876) 922-9267, Fax: (876) 922-9292, E-mail: tjk.uneprcuja@cwjamaica.com

Background
The Convention for the Protection and Development of the Marine Environment in the Wider
Caribbean Region (WCR), or the "Cartagena Convention," is the only binding regional
environmental treaty for the WCR. The Cartagena Convention, presently has 20 States that are
Contracting Parties out of the 28 States in the Region. The Convention is a framework
convention and calls upon its Contracting Parties to develop protocols and other agreements to
facilitate the Convention's effective implementation. The Convention and its Protocols constitute
a legal commitment by these countries to protect, develop and manage their common waters,
individually and jointly.
Two protocols have thus far been developed. The first protocol on co-operation in combating oil
spills in the WCR entered into force in 1986 with the Convention. The second protocol on
Specially Protected Areas and Wildlife, adopted in 1990, is expected to enter into force in 1998.
Work is ongoing on a third protocol on the prevention, reduction, and control of marine pollution
from land-based sources and activities (LBS Protocol). Completion of these negotiations and
adoption of this protocol is expected for the second quarter of 1999.
The LBS Protocol is a regional mechanism that will assist States in the WCR to achieve the
goals and obligations of two international agreements. The United Nations Convention on the
Law of the Sea calls upon Sates to adopt laws and regulations to prevent, reduce, and control,
pollution of the marine environment from land-based sources.
The Global Programme of Action for the Protection of the Marine Environment from Land-
Based Activities (GPA), adopted in Washington in 1995, highlights the need for action to reduce
the pollutant load to the seas from land-based sources activities. Both of these instruments
emphasize the need to act at the regional level to address this problem.
Regional action is particularly important to the WCR. Because of the large number of countries
in a relatively small area, almost the entire marine environment of the WCR falls under national
jurisdiction. Further, the large number of countries and their close proximity and the circulation
patterns in the WCR create a large number of transboundary pollution issues. This situation
exemplifies the need for regional co-operation and coordination to effectively address land-based
sources and activities.

Marine Pollution from Land-Based Sources and Activities in the Wider Caribbean
In 1994, the Caribbean Environment Programme (CEP) of UNEP completed an overview of
land-based point sources of marine pollution in the WCR. The final report of that study (CEP
Technical
Report #33), indicated that domestic wastewater was the largest point source contributor by
volume to the WCR. Domestic wastewater was followed by six industrial categories: oil
refineries, sugar refineries and distilleries, food processing, manufacture of beer and other drinks,
pulp and paper factories and chemical manufacturing. Though not part of the 1994 study which
focused on point sources, urban and agricultural nonpoint sources of pollution are also
recognized as significant contributors to pollution of the WCR.

LBS Protocol Development in the WCR --A new approach --
Two expert meetings held in 1992 and 1994 assisted in shaping the basic conceptual and
structural approach of the Protocol. Negotiations in 1996, 1997 and 1998 have brought the
Protocol to the point where the Contracting Parties have agreed to hold final negotiations in the
first half of 1999. The Protocol as drafted differs significantly from other regional LBS
instruments and, once implemented, should result in tangible positive environmental impacts in
the WCR and on the economies of the Region which are highly dependent on the marine
environment.
The draft Protocol sets forward general obligations, institutional responsibilities, and procedures
for acceptance and ratification in the main body of the Protocol. Specific technical annexes
establish priority source categories and activities and contaminants of concern in the Convention
Area; factors to be used in determining effluent limitations; and management practices, and
specific obligations applicable to specific pollution sources in the region.
The first annex to the Protocol establishes a list of the sources, activities, and contaminants of
specific concern for the WCR as a whole. The second annex establishes the process for
developing regional source-specific controls. Future annexes will be negotiated to address these
priority source categories, activities and contaminants of concern listed in Annex I and, using the
factors set forth in Annex II. These future annexes will set regional effluent limitations and best
management practices. Such annexes will also contain timetables for achieving the effluent
limitations and management practices.
The third and fourth annexes, which are the first of the two source-specific annexes, to be
adopted together with the Protocol, establish effluent limitations for domestic sewage and best
management practices that are to be incorporated into national plans to control pollution from
agricultural non-point sources. The effective implementation of these two annexes will commit
the Parties to making significant improvements to the pollution control practices currently used
in much of the WCR.
If adopted, this agreement will be the first regional seas agreement where effluent limitations and
other obligations are required within a given time frame for specific sources of pollution.

Technical Assistance --making it happen --
In the end, the LBS Protocol is only effective if well implemented. Effective implementation of
the Protocol, will require the co-operation and co-ordination of entities at the international,
regional, national and local levels, the private sector, and donor institutions.
Key challenges for implementing the LBS Protocol include funding to support the identification,
development, design, and construction of pollution control technologies and institutional
capacity building. The Caribbean Regional Co-ordinating Unit of UNEP, as Secretariat to the
Cartagena Convention, along with the Contracting Parties and other relevant organizations is
designing and implementing projects to meet these challenges. Pilot projects for capacity
building in various WCR countries provide models for replicability in other countries.
Technology exchange takes place through workshops on appropriate technologies and best
management practices. CEP has made some progress in these areas, but the need is great. On
behalf of the Contracting Parties to the Cartagena Convention, the Secretariat welcomes
partnerships with others to meet these needs and to prevent, reduce, and control marine pollution
from land-based sources and activities.
For additional information, visit the CEP website at www.cep.unep.org/ or contact:
Mr. Tim Kasten
Programme Officer
UNEP-CAR/RCU
14-20 Port Royal Street
Kingston
JAMAICA
Tel: (876) 922-9267
Fax: (876) 922-9292
E-mail: tjk.uneprcuja@cwjamaica.com

Principles of Wastewater Treatment
Associate Professor Goen Ho
Institute for Environmental Science, Murdoch University, South Street, Murdoch WA 6150, Australia
Tel: (61-8) 9360-2167, Fax: (61-8) 9310-4997, Email: ho@central.murdoch.edu.au

Introduction
Numerous technologies are available for the treatment of wastewater. Many systems have been
constructed and successfully operated ranging from simple on-site systems to sophisticated
large-scale systems with computer operational control. In evaluating the technologies for
application in a particular situation many factors have to be considered. These include capital
cost, availability of fund, financing arrangement, cost-recovery possibility (affordability by the
users), operating and maintenance, and the need for training in operation and maintenance.
There is also the wider consideration of planning to set land for the sewerage pipes, pumping
stations and the treatment plant, integration of wastewater services with stormwater drainage and
with solid waste disposal, community involvement and the local government and non-
government processes to implement the wastewater collection and treatment project. Though
these factors have to be thoroughly considered to ensure long-term viability and sustainability of
a wastewater management system, an understanding of the principles of wastewater treatment is
essential in enabling a proper evaluation of treatment technologies for possible application in a
local situation. We need to be able to answer the question of whether a particular technology will
work or indeed appropriate considering the prevailing economic, social, environmental and
institutional factors mentioned above. Will a high-technology high-cost system be the answer, or
will a low-cost on-site system be adequate, or will a community-scale system be the most
appropriate given the set of local factors? Understanding how these technologies work will go
along way towards answering the question. The understanding will also enable us to assess the
adequacy of existing local technology (one that has been in used locally over many years), how
to improve the existing technology, or how to adapt one of the available technologies to better fit
the local condition.
The purpose of this paper is to develop principles for understanding wastewater treatment by first
of all examining the natural processes taking place in nature that help to purify wastes. These
principles are then applied to the examination of simple wastewater treatment systems that
closely mimic nature. The natural physical, biological and chemical processes are then related to
engineered systems which are more complex and where separate units may be constructed to
carry out the processes. In this paper emphasis is placed on small-scale on-site engineered
systems.

Natural 'Self Purification' Processes
That nature has processes that purify wastes can be deduced by examining what takes place in
pristine forest ecosystem. Water quality of a stream within the ecosystem can be regarded to be
very good. This situation exists even though animal wastes, leaf litter, decaying plants and
animals are constantly produced within the ecosystem. These are decomposed by bacteria
releasing the elements C, N, P and others to be taken up again by plants and cycled within the
ecosystem. Rainwater passing through the ecosystem producing run-off which flows to the
stream hardly picks up any of these.
The natural processes taking place within an ecosystem can be generalised into physical,
chemical and biological processes (Table 1).
Table 1. Natural Physical, Chemical and Biological Processes Purifying Wastes
Principles
Processes
Physical
Settling - removal of solids from water
Filtration - removal of solids as water flows through soil
Aeration - oxygenate water
Adsorption - removal of substances by adsorption to soil minerals or to humus
Biological
Bacterial decomposition - removal of organic substances
There are numerous types of bacteria carrying out specific functions, such as breaking down
carbohydrates, proteins, lipids, converting ammonia into nitrate, converting nitrate to nitrogen
gas
Bacterial competition controlling the population of pathogens
Chemical
Precipitation � removing substances from water percolating through soil minerals/humus

Land Application of Wastewater
Application onto land is a simple low cost system for treatment of sewage. Vegetation is usually
part of the land system, and it can be harvested or grazed. The natural physical, chemical and
biological processes described above remove the organic substances (usually measured by
BOD), solids (SS) and soluble materials from the wastewater. The resulting water percolating to
groundwater or overflowing to a stream can be of considered to have minimal environmental
impact provided that the loading of the wastewater per unit area of land does not exceed the
natural self purification capacity of the system. When the capacity of the system is exceeded
there will be organic substances, nutrients (nitrogen and phosphorus), pathogens and others
remaining unregarded and thus considered to be polluting.

Lagooning of Wastewater
Lagooning of wastewater also treats it. What takes place resembles more what happens in a lake
ecosystem than in a forest ecosystem. In a lagoon system solids settle to the bottom and are
decomposed by benthic organisms. Within the water column bacterial decomposition takes
place. Bacteria and algae function symbiotically with the bacteria releasing carbondioxide and
algae taking up the carbondioxide during the day and producing oxygen from photosynthetic
activity. The oxygen in turn is taken up by the bacteria for respiration. Nutrients are removed
from the water when the algae are harvested (e.g. by fish).

Engineered Systems
The primary objective of engineered wastewater treatment and disposal is the protection of
public health. Wastewater of domestic origin contains pathogens, suspended solids (SS),
substances causing biochemical oxygen demand (BOD), nutrients (nitrogen (N) and phosphorus
(P)) and a hosts of other possible pollutants, which may need to be removed before the
wastewater can be safely disposed. Standards have been developed for the safe disposal of the
wastewater, and so have the technologies to meet them. The technologies that have been
developed are generally for centralised large scale systems associated with reticulated sewerage,
and the treated wastewater is for disposal rather than reuse. Options for reuse are recognised as
being limited with large scale systems in urban areas, because of the need of a reticulation
system for the treated wastewater.
On-site treatment of wastewater for individual houses is a necessity in areas without reticulated
sewerage, but interest in on-site treatment is growing. One reason is that the technology for on-
site treatment is maturing, and reuse of the treated wastewater is an option. Thus the owner of an
on-site system has total control of the wastewater and its use. In an urban community where
there is a desire to develop an urban village the treatment of wastewater from a group of houses
within the urban village community offers the opportunity to achieve what is desired by such
communities, i.e. integrated management of water.
The maturing of the technology for on-site wastewater treatment is due to a large part to the
application of scientific principles to the improvement of the outdated septic tank technology.
This paper therefore broadly reviews the scientific principles applicable to on-site wastewater
treatment and reuse, and assesses available technologies with respect to their science content.
On-site treatment of wastewater may not provide all the answers to the problems of wastewater
disposal and reuse. Issues needing to be addressed are, for example, whether individual
householders can be expected to maintain a sophisticated wastewater treatment unit in the
backyard, and the imbalance between water supply and demand in different seasons
The physical, chemical and biological bases for the treatment of wastewater to remove BOD, SS,
N, P and pathogens are well established. They have been studied as part of efforts to improve the
technologies for large scale wastewater treatment systems. These are shown in Table 2. They
should obviously be applicable to small scale and on-site treatment systems.

Table 2. Physical, Chemical and Biological Principles Relied for Engineered Systems
Principles
Processes
Physical
Screening
Sedimentation
Sand Filtration
Aeration
Adsorption (Activated Carbon)
Membrane filtration
Biological
Removal of BOD:
Use of aerobic bacteria
Use of anaerobic bacteria
Removal of N:
Nitrification
Denitrification
Removal of P:
Luxury uptake
Chemical
Coagulation & flocculation
Precipitation
Chlorination
An example of an application to large scale systems is the conventional primary and secondary
treatment utilising an activated sludge plant. Here raw wastewater is screened to remove large
objects, then grits are removed in an aerated sedimentation tank, followed by sedimentation of
the smaller suspended solids, producing a primary effluent. Further treatment by aerated
microorganisms removes BOD, and sedimentation clarifies the secondary effluent, returning the
microorganisms (activated sludge) to the aeration tank. Secondary effluent containing less than
20 mg/L BOD and 30 mg/L SS can be achieved without difficulty. The 20 mg/L BOD and 30
mg/L SS standard was, in fact, based on what could be achieved by primary and secondary
treatment of sewage. Disposal to rivers or reuse for irrigation of recreational parks is generally
permitted after chlorination to reduce the concentration of pathogens.
It has become more necessary now to remove N and P prior to disposal to rivers or onto land,
because of the need to prevent eutrophication of surface waters. Ammonium-N in secondary
effluent can be removed as ammonia by liming and aeration. Nitrogen can also be removed by
biological nitrification and denitrification. Similarly P can be removed by chemical precipitation
using lime or alum or a ferric salt, or removed biologically.
Sludge from the primary and secondary treatment also needs to be treated prior to disposal or
reuse. Again physical, chemical and biological means are available (Table 3).

Table 3. Physical, Chemical and Biological Bases for Treatment of Sludge from Engineered
Systems
Principles
Processes
Physical
Thickening
Vacuum Filtration
Biological
Anaerobic digestion
Composting
Chemical
Coagulation and flocculation
Incineration
Needless to say, understanding the physical, chemical and biological bases of wastewater
treatment enables us to develop an innovative treatment system to achieve any particular
objective or standard by combining physical/ chemical/ biological units. Innovative treatment
systems include combined BOD and N removal in a series of anaerobic and aerobic chambers, or
alternate aeration and non aeration of one chamber.
Following secondary treatment and removal of nutrients by liming, recharge of groundwater is
possible after coagulation, flocculation, sedimentation, sand filtration (i.e. a rapid sand filter) and
chlorination; and even to produce potable water with further activated carbon adsorption and
membrane filtration treatment.

On-site Treatment Systems
Current on-site treatment systems have generally adopted the technology of the conventional
activated sludge plant for large treatment systems. This is understandable, because the effluent
standard for reuse for garden irrigation is a chlorinated effluent containing not more than 20
mg/L BOD and 30 mg/L SS, i.e. secondary effluent that can be achieved without difficulty using
an activated sludge process. Differences that can be observed are the insertion of a trickling filter
in the aeration chamber to cope with variable flows and the infrequent removal of sludge. Thus
anaerobic decomposition of sludge takes place in the first settling chamber. It appears that
current commercially available on-site treatment units would benefit from a thorough scientific
scrutiny of the operation of their components to optimise overall performance.
If removal of nutrients are required for installation of on-site units in nutrient sensitive
catchments, P can be removed by alum dosing, and N by nitrification and denitrification in
separate chambers or by intermittent aeration of a modified activated sludge set-up.
Hyperchlorination of ammonium in secondary effluent theoretically removes N by oxidation to
nitrogen gas.

If the effluent is used for irrigation of garden plants, there is the question as to why N and P,
which are required by plants, should be removed. There may be an imbalance between plant
requirement for the nutrients and the seasons, with a high requirement in the warmer months than
in the colder months. Rather than removing the nutrients, an alternative is to store the nutrients in
the soil. Soils containing clay have the capacity to sorp ammonium and phosphate present in
secondary effluent. Sandy soils deficient of clay minerals can be amended with clay (or near an
alumina refinery, use red mud, residue from the processing of bauxite into alumina).
Effluent stream segregation is a recognised method for the treatment of industrial wastewaters,
where low volume high strength wastes are segregated from high volume low strength wastes.
Treatment of the former can be more effectively carried out in a smaller system, while the latter
may not need treatment or little treatment. This situation presents itself when we consider on-site
treatment of domestic wastewater, where we have a low volume high strength waste from the
toilets (commonly called black water) and a high volume low strength waste from the rest
(bathroom, laundry, kitchen), commonly called grey water. Development of on-site systems
taking advantage of this should be encouraged. We are now beginning to see dry/ composting
toilets, and proposals for the reuse of grey water.

Management of On-Site Systems
Management issues which need to be discussed are public health, maintenance of an on-site unit
and rating.
Public health (including the health of owners) is guarded through standard for the reuse of the
treated effluent. This standard is well defined now in terms of the number of coniform organisms
which should not be exceeded in the effluent. This is turn is related to the degree of treatment
(secondary effluent standard) and chlorination with a minimum chlorine residue. If a unit is
properly operated the effluent standard should be achieved. Thus the issue is closely related to
the next, i.e. of maintenance.
Can a lay householder be expected to maintain a sophisticated on-site unit? The answer to this
question is dependent on a number of factors. Robustness of the technology is a key factor. On-
site units are now designed with reliability as good as modern household appliances (e.g.
refrigerators) and can be regarded as such. Regular maintenance is required, e.g. sludge removal.
Ideally a regular, say three monthly, maintenance contract should be an available option with the
supplier of an installed on-site unit. The cost affordability of this option is dependent on whether
a property is in a reticulated sewerage area and hence rated, i.e. whether connected to the sewer
or not.
Since on-site units are designed for non-sewerage reticulated area, the question on rating only
arises when sewerage reticulation comes to an area where an on-site unit has been installed.
Should a property previously not on reticulated sewerage be rated when reticulated sewerage is
available, even though the property has a sophisticated on-site treatment unit? This question will
become more relevant when the concept of integrated management of water is adopted in an
urban community wishing to develop an urban village.

very good. This situation exists even though animal wastes, leaf litter, decaying plants and
animals are constantly produced within the ecosystem. These are decomposed by bacteria
releasing the elements C, N, P and others to be taken up again by plants and cycled within the
ecosystem. Rainwater passing through the ecosystem producing run-off which flows to the
stream hardly picks up any of these.
The natural processes taking place within an ecosystem can be generalised into physical,
chemical and biological processes (Table 1).
Table 1. Natural Physical, Chemical and Biological Processes Purifying Wastes
Principles
Processes
Physical
Settling - removal of solids from water
Filtration - removal of solids as water flows through soil
Aeration - oxygenate water
Adsorption - removal of substances by adsorption to soil minerals or to humus
Biological
Bacterial decomposition - removal of organic substances
There are numerous types of bacteria carrying out specific functions, such as breaking down
carbohydrates, proteins, lipids, converting ammonia into nitrate, converting nitrate to nitrogen
gas
Bacterial competition controlling the population of pathogens
Chemical
Precipitation � removing substances from water percolating through soil minerals/humus

Land Application of Wastewater
Application onto land is a simple low cost system for treatment of sewage. Vegetation is usually
part of the land system, and it can be harvested or grazed. The natural physical, chemical and
biological processes described above remove the organic substances (usually measured by
BOD), solids (SS) and soluble materials from the wastewater. The resulting water percolating to
groundwater or overflowing to a stream can be of considered to have minimal environmental
impact provided that the loading of the wastewater per unit area of land does not exceed the
natural self purification capacity of the system. When the capacity of the system is exceeded
there will be organic substances, nutrients (nitrogen and phosphorus), pathogens and others
remaining unregarded and thus considered to be polluting.

Wastewater Collection and Treatment Systems for Large Communities in the
Wider Caribbean:

Wastewater Collection and Treatment Systems for
Large Communities in Venezuela
Mark Lansdell
Mark Lansdell Asociados, Parque Central, Edif. Catuche, 12-L � Apdo. 17156, Caracas, Venezuela
Tel: (582) 571-4869, Fax: (582) 574-2718, Email: Lansdell@telcet.net.ve

Abstract
A brief history of sewage treatment is presented along with experience of treatment systems in
less developed countries for communities of over 500,000 people.
Some of the sewage treatment systems in Venezuela are presented and the technical and
institutional problems which occurred during construction and operation are described and some
of the solutions are presented. It was found that the most simple systems were the most effective
and that it was important to develop solutions appropriate to local needs and avoid the
technological dependence on imported spare parts.

Keywords
Low Cost Treatment; Oxidation Ponds; Plug Flow Constant Level SBR; MSBR

Introduction
At present 50% of the world's population resides in urban centres of over 500.000 and some 20%
in the world's megacities of over 5 million. The world has embraced the water closet and the
water carriage system for the transport and dilution of its wastes in the urban environment. The
volumes of wastewater produced have overcome the assimilative capacity of lakes, rivers and the
oceans. The large population centres accentuate the problem and in very few cases has an
environmentally sustainable solution been found.
There are a number of large communities in the wider Caribbean still in need of a sustainable
solution to their wastewater management problem. What follows is a brief history of worldwide
experience of wastewater treatment and resource conservation and a description of the author's
efforts in Venezuela.

History
In the east, both human and animal waste has for millennia been regarded as a resource to be
recycled to the land to maintain its fertility and for the fertilising of fish ponds. Indeed Chinese
fish ponds constitute the earliest form of stabilization ponds for treating night soil collected from
household vaults (Baozhen 1987). The largest example of a lagoon - fish pond system is that
which serves the sewers of Calcutta, India, which covers some 5000 Has. and produces 20 tons
of fish per day for human consumption, some 20% of the city's total fish demand (Strauss 1990) .
In the west, human waste has received very little recognition as a resource and most early
references refer to "sewage disposal" despite some failed attempts to make money out of the
fertilizer value. In Britain, where the water closet was first introduced, the connection of house
drains to street sewers was made legal after 1830. This caused the pollution of rivers, many
cholera deaths, and injunctions against several large towns in the 1850's. This crisis motivated
the first investigations of sewage purification by land treatment on "Sewage Farms". From these
investigations rules were derived for determining the area of land required for a given sewage
flow according to the type of soil. For example, the area of land required for the treatment of
sewage by "broad irrigation" over clay soil amounted to nearly 20% of the urban area served.
The Werribee facility serving Melbourne, Australia, since 1895 is the largest surviving example
of a municipal broad irrigation system.
The high cost of land brought the need to intensify treatment in a smaller area and research in the
1870's brought the first trickling filter as a development of soil filtration with ever larger grain
size. This so called "filter", really an attached growth reactor, was adopted widely in Britain and
overseas. One of the largest systems being the Minworth plant serving the city of Birmingham,
recently decommissioned after 100 years service. The rotating biological contactor is a
descendant of this system. Instead of trickling the sewage over the media, the media is attached
to rotating discs which alternatively immerse and expose the media to the air.
The Septic Tank has been used on quite a large scale in its more developed form as the two
compartment "Hydrolytic" or "Imhoff Tank" for the removal and digestion of solids in the
primary treatment stage. The largest example still in service since 1935 is at the Stickney Plant
serving Greater Chicago and still handles half the flow of this, the largest treatment plant in the
world. This was also the system used at Cairo in 1914 in conjunction with trickling filters.
The pressure forever more space efficient systems brought the invention of the suspended growth
reactor or "Activated Sludge" system in Manchester in 1914. This system, although far more
energy intensive than previous technology, was adopted rapidly and several large plants had been
built worldwide by 1930 including Milwaukee, New Delhi, and New York City.
The activated sludge system has seen many variations over the last 85 years, in the author's
opinion, the most significant were the modifications allowing the biochemical removal of
nutrients. Once again this was a technical advance borne of a necessity. In southern Africa, water
is very scarce and needs to be reused several times. In the cities of Harare and Johannesburg
some 40% of the sewage flow is returned for public water supply. The urban population
explosion has caused impoundments to become increasingly eutrophic, the algae making

conventional water treatment systems for potable use difficult to manage. In order to reduce
nutrient loads, the Republic of South Africa became the first country to introduce phosphorus
and nitrogen limits of 1 and 10 mg/l on municipal effluents.
More recent developments in the 1980's have included submerged and fluidised beds which
combine fixed and suspended growth in order further to reduce the area occupied by the
treatment system but these systems remain very energy intensive.

Technological Relevance in a Developing World Context
The historical outline above describes the technological evolution which took place when Europe
and North America where developing countries. As we have seen, the resource conservation
aspect has been lost and the solutions have become increasingly costly in environmental goods.
Large amounts of energy are required to operate activated sludge plants, dry and incinerate
sludge, and to make and transport artificial fertilizers to farmland to replenish the nutrients we
send down the sewers to enrich our lakes and oceans. This arrangement will not pass a
sustainability test.
The Calcutta example on the other hand appears entirely sustainable, relying only on energy
from the sun and achieving the recycle of resources and conserving nutrients. These solutions
appear to be only possible where there is sufficient space. But sewage can almost always be
transported to an available space. Mexico city's sewage is transported up to 50 km in tunnels and
by 200 km of canals before being used, albeit in crude form, for irrigation on 60.000 Has of land
(Strauss, 1990) as is the sewage of Santiago, Chile.
The use of sewage in crude form for irrigation or fish farming in the developing world however
brings a need for barriers to the propagation of endemic diseases such typhoid, cholera and
parasitic organisms such as intestinal nematodes and the pathogenic protozoa such as amoeba
and giardia.
These organisms can be effectively removed in a series of oxidation ponds as detailed in the
publications of the World Bank (Technical Paper N_s 7 & 51) and WHO (Technical report series
N_ 778). The important point being that for resource recovery and drought situations where
sewage must be used for irrigation, traditional parameters such as BOD become irrelevant and
public health aspects such as the presence or absence of parasite eggs and numbers of faecal coli
become the major concern.

Water Reuse
Where water resources are limited and the effluent must be discharged to a river system with
urban water supply impoundments downstream, as occurs in southern Africa, the options become
more limited due to the need to reduce the nutrient load in order to avoid eutrophication.

The significance of Phosphorus (P) can be put in perspective if we remember that I kg of P can
give rise to 111 kg of biomass which on death will exert a COD of 138 kg supposing that the
composition of algae is:
C106 H263 O110 N16 P
Environmental Management solutions such as detergent production and watershed management
can help but will not prevent eutrophication episodes especially in the tropics where
temperatures are high and the days usually sunny.
Where the urban populations are large, wetlands are not a practical option due to the need to
harvest the biological growth and avoid internal P recycle. In these cases more sophisticated
sewage treatment processes are needed and drinking water treatment technology adapted to the
presence of algae in the raw water.
These processes include the activated sludge process modified for removal of nitrogen and
phosphorous down to 1mg/l _P and 10 mg/l _N. In some cases this may be followed tertiary
treatment consisting of coagulant addition and sand filtration for the removal of P down to
around 0,15 mg/l.

Sewage Treatment in Venezuela
The author was posted to Venezuela in 1973 with a British consulting firm to study the clean up
of the river supplying Caracas's water supply. Since 1978 his own firm has been involved with
the design construction and operation of over 30 different treatment systems ranging from 2000
to 4.000.000 population.
The dilemma to be faced was which technology to use when lagoons were not a choice. This
arose in the first plants which were designed on the Island of Margarita.
Where treatment systems are required to produce a low solids effluent for urban reuse and plant
location requires low odour risk, variations of the activated sludge system have been used. These
variants have been designed with local limitations in mind using unit processes which have not
been used in developed countries since the early years of this century but which still have a place
in situations where unskilled manpower is plentiful and foreign currency is in short supply.

Porlamar - Pampatar, Margarita Island
The Island of Margarita is the principal Venezuelan coastal tourist attraction and has been a free
port since 1972 with regular international tourism starting in 1985. Its beaches are the best of the
Venezuelan coast but increases in sewage flow overloaded the original sea outfall systems and
beach coliforms exceeded 200 faecal coliforms/100ml for the first time in 1980 with rapid
deterioration thereafter.

The wastewater master plan for the principal urban area, Porlamar - Pampatar, was prepared in
1975 and foresaw urban and rural reuse of the effluent and biosolids for irrigation and
improvement of the arid sandy soils. Drinking water is brought to the island through a very
costly 30 km pipeline and there is little to spare for other purposes.
The sewage from the Porlamar metropolitan area is pumped to a single treatment plant "Dos
Cerritos" located some 3 km inland. This plant was put into service in 1989 the first stage of
which has a capacity of 200.000 PE and 600 l/s average flow.
The sewage arrives via a 1000 prestressed concrete pipeline at the inlet works where gross solids
and rags are removed in a 12m wide hand raked screen with a 3.5 cm clear opening. This screen
is cleaned in about 30 mins. by one labourer once per day. The flow is then divided between
three constant 0.35m/s velocity grit channels 20m. long. The grit is removed hydraulically, one
of the three channels being cleaned every two weeks.
The flow then proceeds to an extended aeration tank with partitions to split the 17300m3 volume
up into 5 cells in series. Along the long axis of the tank there is a concrete bridge from which are
suspended 11 high speed (1200 RPM) surface aerators of 75 HP each.
The mixed liquor from this tank is divided amongst six settling tanks each 20,0 X 20,0 square
with four inverted pyramidal pockets with a 7.0m depth of water. Sludge from each pocket is
withdrawn continuously through 250 pipes and telescopic valves into a return sludge collector
and lifted by screw pumps into the inlet end of the inlet works.
The clarified effluent is decanted through a perforated 750 pipe around four sides of each settling
tank and discharged over a measuring weir into a series of two maturation ponds of five days
design total retention time. Each pond is divided by walls into five cells in series. Effluent from
the final cell not used in irrigation overflows and discharges through a 3.5 km. pipeline to the sea
shore.
Hydraulic control of sludge age is obtained by withdrawing mixed liquor from the aeration tank
through a constant head orifice to the sludge lagoons. The size of orifice varies with the sludge
age selected there being orifice plates for sludge ages 5, 10, 15, 20, 25 and 30 days along with a
blank one. The plate to be inserted varies with the anticipated loading which depends on the
tourist flows. Off season resident connected population is around 80.000 and during the peak
season July - August this rises to 130.000 based on the observed flow and strength of the sewage
calculated at 50gBOD/PE/day.

Operating results during 1997 (arithmetic means) were as follows:

Crude
ASE
MPE
Av. Flow
400 l/s

N_ of samples
51
51
51
BOD 211
11.0
10.3
mg/l
SS 117.6
7.8
7.5
mg/l
F. Coli.
107 � 108
900.000 20
orgs/100ml
(ASE = Activated sludge effluent; MPE = maturation pond effluent)
Imported equipment at this plant included: cast iron gates (US), aerators (US) and screw pumps
(FRG) and accounted for about 10% of the $ 4 million cost excluding land. Each aerator is
provided with a mechanical timer which has allowed the aeration intensity to be graduated to the
load with an efficiency of around 0,65 Kg BOD removed per KWh.
Problems which have arisen at the plant include:
� Power Cuts: The power supply to the island is subject to an average of three cuts per
week of 30 mins. but some have lasted over 12 hours with no adverse affect on the final
effluent.
� Sludge Lagoons: Due to leakage of division dykes, the sludge has not dried out in the
drying lagoons which will shortly be reconstructed at a higher level.
� Salt Water Infiltration: Insufficient care was taken during the laying of the main 1500
sewer below sea level in the town with the result that some 5 l/s of brackish water is
infiltrating into the sewer system raising the conductivity from 600�S to 2000�S
rendering the water too salty for certain crops.
� Filamentous Algae: The first four cells of maturation ponds have experienced heavy
growth of filamentous algae which makes them unsightly but does not alter their
disinfection efficiency.
Within 30 days of the diversion of sewage to the new plant, coliform levels of coastal waters,
previously above 20.000 had dropped to below 50/100 ml.

Juangriego, Margarita Island
The bay of Juangriego is one of the most picturesque on the island and is well known for its
sunsets. The town has had a sewer system and an 800m long / 350 mm sea outfall since 1970.

With increasing development this arrangement became overloaded and bathing from beaches in
the bay was prohibited in 1982.
To restore beach water quality and allow sewer extensions in the area, a treatment plant was
completed in 1990 for a first stage population of 50.000 PE 150 l/s average flow.
The plant consists of an inlet works followed by a concrete lined reactor basin. This basin has
been designed as a three channel plug flow constant level SBR (MSBR). The basin is divided
into three channels longitudinally with three 40 HP floating aerators in each channel. At each end
of the central channel, hanging flap valves induce an "S" shaped flow pattern. Sewage is
introduced via pneumatically operated gates into one of the outer sections while clear effluent is
withdrawn from the opposite side of the basin where the aerators are turned off allowing
sedimentation. In this way the functions of aeration and sedimentation are undertaken in the
same basin obviating the need for expensive clarifiers and sludge return pumps.
Operating results of the plant during 1994 where as follows:

Crude
MSBR Effect
Final Effect
Av. Flow
25.9 l/s

N_ of samples
50

BOD 217.7
14.7
8.7
mg/l
SS 130.4
6.4
4.4
mg/l
F. Coli.
3.200.000

25 orgs/100ml
(ASE = Activated sludge effluent; MPE = maturation pond effluent)
The timing of the inlet and outlet gates and the aerator motor starters is controlled by a simple
cam timer with an eight hour cycle. The imported material for this plant consisted only of the
aerators as the gates and MCC were made locally. The cost of the plant excluding land was
$900.000.
Problems which have presented themselves include:
� Bacterial Foam: An unidentified foam appeared after about 18 months of operation and
gradually built up to a depth of 25 cm before a solution was found. Chlorinating, liming,
skimming and jetting where all tried to no avail. Finally the scum boards on the effluent
weirs where removed and placed around the inlet to the maturation pond. The area
covered by foam in the aeration tanks is now rarely more than 10m2 and that behind the
scum board never passes 1m2.

� Sponge: A type of sponge grew inside the 600m final effluent pipeline completely
blocking it. A routine has been established in which the lagoon outlet is closed with a
flash board once per month, a head builds up and when released flushes out any sponge
buildup.
� Ecological Balance: The new lagoon created by the scheme caused an invasion of insects
which in turn caused a plague of small white spiders on the trees to leeward. These where
then eaten by birds and fish ate the larvae of the insects. This took about two years to
reach equilibrium during which time the treatment plant was blamed.
� Filamentous Algae: The first three cells of the maturation ponds have a heavy growth of
filamentous algae which as at Dos Cerritos makes them unsightly but does not effect
efficiency.

Lake Valencia Scheme
Lake Valencia is one of largest freshwater bodies in South America with 350 km2 of surface
area, a volume of 7500 million m3 with a present water level of + 408m. above sea level. Two
major population centres (> 800.000 each) are located in the catchment along with 30% of
national industry. Around the year 1750 the lake level fell below its natural overflow of level +
427m due to tree cutting and river diversion for irrigation of the sugar plantations which were
established around the perimeter. In 1978 the lake level reached its lowest point + 401,50m and
has since risen to + 407,9m, due to transfer of water from other catchments.
The discharge of sewage, industrial wastes and agricultural runoff along with 200 years of
evaporation have left the lake hypertrophic with a conductivity of 2000�S; sulphates 550 mg/l; P
0,5mg/l and _N 2 mg/l. National policy is to improve the lake quality for tourism, water supply
and fish culture.
The Inter American Development Bank approved a US$ 125 million scheme with the following
objectives:
o Treatment of domestic and industrial wastes
o Control of Lake level
o Reuse of effluent in irrigation
o Closure of wells to aid aquifer recovery
o Aquifer recharge and desalination for future urban use
o Indirect urban reuse
o Reduction of artificial fertilizer requirements
The approved scheme calls for the construction of 90 km of interceptor sewers, 17 km force
main and three treatment plants:

Name of WWTP

La Mariposa
Los Guayos
Taiguaguay
� Capacity (PE)
800.000

1.000.000
2.000.000
� Design Av. flow
2400 l/s

2400l/s

5.000 l/s
� Type

AS
Tertiary

Lagoons Lagoons
� Area Served
Central &

East Valencia
Cagua
West Valencia
Guacara

Turmero
Maracay

(PE = person equivalent at 50g BOD/day)
The two larger plants are lagoon systems with anaerobic units at the head end which include
recirculation of facultative effluent for control of odours and stabilization of the pH. In both
cases the effluent is to be used for irrigation in order to reduce the use of wells which have
severely depleted the aquifer causing intrusion of salty water from the lake.
The Taiguaiguay system is a classic example of carrying the sewage to a remote lagoon and
irrigation site rather than employing a local sophisticated plant. The sewage from Maracay will
be pumped by natural gas driven pumps through 17 km of 72" force main to the Taiguaiguay
lagoon system which located adjacent to an existing 90 million m3 dam and 6000 ha. irrigation
system. The idea being that effluent will not return to the lake but recharge depleted aquifers thus
reducing the lake's tendency to rise.
To control lake levels, the Mariposa WWTP effluent will be discharged outside the catchment to
the river Pao system which is impounded and transferred back to the Valencia city water supply
thus creating a closed circuit indirect reuse system. The plant therefore must produce a very good
effluent low in nutrients.
The impoundment already has eutrophication problems with dry season blooms of blue green
algae Anabaena and Microcystis which cause severe taste and odour problems in the supplied
water. Plans are under way to modify the drinking water treatment processes to handle eutrophic
water. This is in recognition of the fact that even after point nutrient point source control has
been implemented, catchment management in the developing world is difficult. Eutrophication
becomes a fact of life in high intervention catchments and one must adapt and learn to live with
it.
The Mariposa plant employs the MSBR variant of the activated sludge system (Juangriego type)
designed to remove N and P. The secondary effluent is then dosed with alum and given tertiary
filtration through a 1m bed of 3 mm sand in order to remove solids, intestinal nematodes and P.
The construction phase of the scheme is 80% complete and the WWTP's should all come on line
during the latter half of 1998.

Discussion
In Venezuela a country which shares similar social and climatic characteristics with the rest of
the Caribbean, the oxidation pond system remains the first choice for those cases where there is
sufficient space and distance from local communities. In the case of Margarita and Valencia
circumstances demanded more sophisticated solutions. Here, a local variation of the activated
sludge system has been developed which minimises the need for imported equipment and is
consistent with local construction and operation skills limitations. The use of maturation ponds
of five days nominal retention time is sufficient to produce high bacterial quality nematode free
effluents without chlorination.
The activated sludge systems described in this paper have all been built for less than $20/PE or
$80/m3/day average flow (250 l/day/PE) whilst the lagoon systems cost around $4/PE excluding
land in all cases. The electrical energy used in the activated sludge plants is about 3,5 watts per
person equivalent of 50g BOD/day which costs about $1,25/PE/year. Operation and maintenance
costs come to around $2,00/PE/year making a total annual capital and operating cost of about
$5/PE/year, about ten times more than the cost of the lagoon systems but still only 10% of the
cost of plants in developed countries. This figure also represents about 1% of the minimum wage
for a family group of 5 persons.
The public sector in Venezuela has traditionally suffered from the ills of bloated payrolls, union
abuses, uncompetitive salary structure, political interference, under funding of maintenance
operations and labyrinthine procurement policies which make day to day consumables
purchasing very difficult. However the use of operations contractors at the plants described has
assured that they are well maintained as shown by the operating results. The water and sanitation
sector remains underfunded however due to political reluctance to apply, charge and collect
realistic tariffs and to the idea that the service should receive blanket subsidies from the centre.

References
Baozhen, W. (1987) The Development of Ecological Wastewater treatment and Utilization
Systems in China. Wat. Sci. Tech. Vol. 19, N_ 1/2 pp. 51-63
Carbonell, L.M. and Lansdell, M. (1991) Wastewater Treatment and Reuse aspects of Lake
Valencia, Venezuela. Wat. Sci. Tech. Vol. 24, N_ 9 pp. 19-30
Lansdell, M. (1987). The Development of Lagoons in Venezuela. Wat. Sci. Tech. Vol. 19, N_ 12
pp. 55-60
Strauss, M. and Blumenthal, U. (1990) Use of Human Wastes in Agriculture and Aquaculture
IRCWD Report N_ 08/90, Duebendorf, Switzerland

Wastewater Treatment Systems in Guatemala,
Central America
Ing. Adan E. Pocasangre Collazos
Executive Director of the Liquid and Solid Wastes Council, CONAMA, 7a Ave. 7-13 Zona 13,
Guatemala, Guatemala
Tel: (502) 440-7916/17, Fax: (502) 440-7938, Home Tel/Fax: (502) 474-3601

Abstract
In Guatemala, Central America live more than 10 million people and exist more than eighty
wastewater treatment plants (wwtp), with different types and process. Most of them attend
suburban areas, (small communities), others attend private sections of housing projects, and
some others industries. Nowadays authorities really don't know exactly the number of
wastewater plants existing in the entire country and if they are working correctly. Due to this
situation this paper is entitled to get a closer look to the wastewater plants identified and their
actual state of maintenance and operation. Also it will show the experience in the use of
Trickling Filters in the Republic of El Salvador in Central America.

Introduction
The centralization of populations gives origin to the need of cover the demand of water supply.
This situation increase day by day the amount of wastewater flow that is been drained to the
sewage pipes without previous treatment. With this situation it is been deteriorating the quality
of the streams, rivers, lakes, etc. Most of the industries are draining their wastewaters to the
sewage systems without previous treatment contributing to the contamination.
According to the Sectorial Analysis of Water Supply and Wastewater in Guatemala, the served
population with sewage pollution control (sanitary sewage and latrines) is as follows:
- Total Population *

10,322
- Served Population

3,142
% Served Population

60%
- Urban Total Population

3,978
- Served Urban Population

2.868
% Served Urban Population

72%
- Rural Total Population

6,344
- Served Rural Population

3,274
% Served Rural Population

52%
* in thousands
Source: Sectorial Analysis of Water Supply and Wastewater in Guatemala - 1994

In Guatemala exist more than 18,000 communities in the whole country where less than 1% have
treatment systems for wastewater, discharging about 1,000,000m3/day of wastewater without
treatment at the rivers, lakes, streams, etc.

Actual Situation of Treatment Wastewater Plants
Twenty of the identified wastewater plants have stabilization lagoons units as treatment, in
primary or/and secondary treatment. 17 are Imhoff tanks, 12 with Trickling Filters, 4 with UASB
(Units Anaerobic Sludge Blanket), and the others with different units. The information shown on
the following tables is: location; institution in charge; and if the system is properly working.
No.
Ubicacion
Responsible
Funcionamiento
1 Atescatempa,
Jutiapa
Municipalidad
No
2 Caslllas,
Santa
Rosa
Municipalidad
Si
3
Catarina, San Marcos
Municipalidad
Si (parcial)
4
Flores Costa Cuca, Quet.
Municipalidad Si
(parcial)
5 Guastatoya
I
Municipalidad
Si
6 Guastatoya
II
Municipalidad
Si
7 Ipala
Municipalidad
Si
(parcial)
8 Pajapita
Municipalidad
Si
(parcial)
9 Pasaco
Municipalidad
Si
(parcial)
10 Patzun
Municipalidad
No
11 Retalhuleu
Municipalidad
Si
(parcial)
12
Sanarate I
Municipalidad
Si (parcial)
13 Sanarate
II
Municipalidad
Si
14
San Agustin Acasaguast
Municipalidad
No
15
San Esteban Chiquimula
Municipalidad
Si (parcial)
16
San Juan Comalapa
Municipalidad
Si (parcial)
17 Solola
I
Municipalidad
Si
18 Tiquisate
I
Municipalidad
Si
(parcial)

No.
Ubicacion
Responsible
Funcionamiento
19 Tiquisate
II
Municipalidad
Si
(parcial)
20 Villa
Canales
Municipalidad
No
21 Zacualpa,
Quiche
Municipalidad
No
22 Nimajuyu
BANVI
No
*
23 Bello
Horizonte
EMPAGUA Si
(parcial)
*
24 Villalobos
1
BANVI
No
25 Villalobos
2
BANVI
No
*
26 Mesquital
BANVI
No
*
27
Santa Isabel ll
BANVI
No *
28
Justo Rufino Barrios
-
No
29
Peronia, Mixco
Municipalidad
Si (parcial)
30 San
Cristobal,
Mixco
Municipalidad
No
31 Berlin,
Mixco
Municipalidad
No
32
San Jacinto, Mixco
Municipalidad
No
33
USAC (Guate)
USAC
Si (parcial)
34
Villa Hermosa, Villa Can.
Municipalidad
No
35
Ribera del rio, Villa Can.
Lotificadora
Si (parcial)
36
Aurora l y ll
Municipalidad
No
37 Elgin
ll
Municipalidad
No
38
Lomas de Portugal, mix.
Municipalidad
Si (parcial)
39
Molino de las Flores, mix.
Municipalidad
Si (parcial)
40
Valles de la Mariposa l y ll
Lotificadora
Si (parcial)
41
Santa Rita, Mixco
Municipalidad
Si (parcial)
42
El Tabacal
Lotificadora
Si (parcial)
43
San Cristobal 2, Mixco
Municipalidad
-

No.
Ubicacion
Responsible
Funcionamiento
44
El Bosque, Mixco
Municipalidad
-
45 Elgin
Sur,
Mixco
Municipalidad
No
46 Villa
Sol,
Guatemala
Lotificadora
-
47 Riveras
del
Pacifico
Lotificadora
-
48
Taxisco, Santa Rosa
Municipalidad
Si (parcial)
49 Calapte,
San
Marcos
Municipalidad
-
50
Puerto Quetzal
Puerto Quetzal
-
51
Cent. Recreat. Pto. Quetz
Min. de la Defensa
No
52
Base Aerea Sur, Reu.
Min. de la Defensa
-
53
Zona Mil. No. 10/Jutiapa
Min. de la Defensa
-
54
Zona Mil. No. 23/Peten
Min. de la Defensa
-
55
Zona Mil. No. 19/Huehue
Min. de la Defensa
-
56
Zona Mil. Zacapa
Min. de la Defensa
-
57
Santa Elena Barilas, V.C.
Municipalidad
No
58
Central de Mayoreo, Guatemala
Municipalidad
-
The following table shows the wastewater treatment plants that are in construction process in
1998.
No.
Ubicacion Responsable
1 Tiquisate,
Escuintla
Municipalidad
2 Tiquisate,
Escuintla
Municipalidad
3 Pajapita,
San
marcos
Municipalidad
4
El Tesoro, Mixco
Municipalidad
5 Teculutan,
Zacapa
Municipalidad
6 Teculutan,
Zacapa
Municipalidad
7 Estanzuela,
Zacapa
Municipalidad

No.
Ubicacion Responsable
8
Boca del Monte, V. C.
Municipalidad
9 Camotan,
Chiquimula
Municipalidad
10 Camotan,
Chiquimula
Municipalidad
11 Taxisco,
Santa
Rosa
Municipalidad
12 Solola,
Solola
Municipalidad
13 Panajachel,
Solola
Municipalidad
14 Jocotan,
Chiquimula
Municipalidad
15 Jocotan,
Chiquimula
Municipalidad
16
San Jose La Arada, Chiquimula
Municipalidad
About the operation, the wastewater treatment plants are working precariously, only 8.7% are
working with a removal more than 60% of their capacity. The management of the service is
responsibility of the local governments in 65%.

Experience in the Use of Trickling Filters
The use of Trickling Filter in Guatemala like in El Salvador is been popularize lately, due to the
topographic conditions (high slopes) and the availability of the use of the land for the location of
this unit.
With those systems are reached removals of 40 to 50 mg/lt of BOD using pretreatment by grid
and sand removal and primary treatment with sedimentation, secondary treatment with Trickling
Filters and Secondary Sedimentation.
The Trickling Filter in this country has been modified changing the entrance device from
movable to fixed, due to the difficulty to build or import this device using channels with triangle
weirs as distribution system.
The advantages of using the Trickling Filter are Low Maintenance Cost and Operation
Simplicity.

Small Community Wastewater Treatment Systems:

Recirculating Filter Technologies; Recent Developments
and Applications in Jamaica
Christiane Roy and Grace Foster Reid
Option Environment Inc, 2360 Avenue de La Salle, Bureau 202, Montreal, Quebec H1V 2L1, CANADA
Tel: (514) 257-6380, Fax: (514) 257-6382, Email: croy@opt-env.qc.ca

Intermittent filters are well known domestic wastewater treatment technologies. They are
commonly found in rural and periurban areas where they can be used for on-site treatment or
community systems. Individual homes, residential developments, resorts, golf clubs, and out of
town businesses or industries are examples of potential applications of these technologies.
Intermittent filters are septic systems that can be operated as single pass or recirculating systems.
For flows up to 1 000 cubic metres per day, recirculating filters are most appropriate; they are
low cost systems both in terms of capital investment and operation. Being septic systems, they
include one community or several smaller septic tanks. The septic tank effluent is collected and
brought to the treatment site through a small diameter collection network that carries only liquid
effluent. The treatment system is comprised of two major components: the recirculation tank and
the filter unit. A simple timer controls 0,5 HP pumps that feed the wastewater on the filter
through a low-pressure distribution system; the filtered water flows back to the recirculation tank
by gravity where a splitter valve directs a portion of the treated water to disposal.
Treatment efficiency is a high quality secondary level with typically 5-day Biochemical Oxygen
Demand (BOD5) and TSS values below 15 mg/L; faecal coliform counts are reduced by two or
more orders of magnitude. The treated water can be disposed in a receiving water body or in the
soil, depending on local conditions and regulatory requirements. Recirculating filters are simple
to operate and require little maintenance.
For individual homes and very small systems with daily flows below 10 m3/d, single pass
systems may be used. These systems do not require a recirculation tank but use a larger filter
unit.

Intermittent Textile Filters
Recent developments using non-woven textile coupons as a treatment medium allow a
significant decrease in the space requirements for this type of technology, which already
compares favourably to other technologies available for community systems (Table 1).
Conventional leachfields are designed at loading rates of normally 4 cm/d or less whereas
recirculating sand filters can receive 20 cm/d and therefore occupy five times less space.

Recirculating textile filters can be loaded up to 180 cm/d, which represents a further major space
reduction. At such high loading rates, mass loading should always be verified. Single pass
systems are normally ten times smaller than leachfields.

Table 1: Comparison of Leachfields and Intermittent Filters
Type of System
Typical Hydraulic Loading Rate
Surface Area
Conventional leachfield
4 cm/d
2 500 m2 for 100 m3/d
Recirculating sand filter
20 cm/d
500 m2 for 100 m3/d
Recirculating textile filter
100 to 180 cm/d
55 to 100 m2 for 100 m3/d
Single pass textile filter
40 to 60 cm/d
2,5 to 4,0 m2 for a home
This space economy is due to the hydraulic properties of the textile coupons. Their water holding
capacity combined with their unique porosity made it possible to develop a treatment process
based on extended contact times between the wastewater and the biomass that develops and
attaches to the treatment medium. As a result, the filter unit becomes a treatment reactor that can
be loaded at much higher hydraulic or mass loading rates than filters packed with a granular
medium. The surface area can be reduced by a factor of five to nine, depending on treatment
goals and wastewater characteristics. For typical domestic wastewater (septic tank effluent
BOD5 = 160 mg/L), and treated water quality with BOD5 and TSS values lower than 10 mg/L, a
space reduction factor of five can be expected.
In order to provide sufficient oxygen for aerobic biodegradation of organic pollutants, forced
aeration is a requirement in textile filters. This goal is achieved by using a small ventilator (80 to
100 watts).
Treatment results from one residential unit and one commercial unit are presented below
(Table 2). The residential unit treats an average flow of 600 L/d with a single pass textile filter
that is 1,5 m_ in surface area and comprised of three 15-cm textile layers. The commercial unit
serves a shopping centre. The average daily flow is in the order of 6,8 m3/d; the wastewater is of
a very high strength due to the presence of a meat market on the premises. The treatment system
is a recirculating textile filter with six filter modules covering a total of 17,3 m2; each module is
made of three 15-cm textile layers.

Table 2: Textile Filter Treatment Results
System
Flow
HLR1
MLR2
BOD5
TSS
F. coliforms
(m3/d)
(cm/d)
(g/m2-d)
(mg/L)
(mg/L)
(CFU/100ml)
Influent
Influent Effluent
Influent
Effluent
Effluent
Residential 0,6 41 86
209
5,4
71
5,3
1,35
E5
980
Commercial 6,8 34 121
355
5,4
72 3,6
5,64
E5
2
800
3. HLR = hydraulic loading rate
4. MLR = mass loading rate

Alcan Jamaica's Kirkvine Plant
Another advantage of recirculating filters is the possibility of incorporating other treatment
components to meet special treatment needs. A good example is the treatment system recently
constructed to treat the domestic wastewater at the Alcan Jamaica plant in Kirkvine. This system
is designed to treat 45 m3/d. Due to the new National Resource Conservation Authority sewage
effluent standards, strict treatment goals were set for nitrogen in addition to conventional BOD,
TSS, and coliform goals (Table 3).
Table 3: Kirkvine Plant Treatment Goals
DBO
-
5
TSS
NO3
Faecal coliforms
(mg/L)
(mg/L)
(mg N/L)
(CFU/100 ml)
20 20 10 1000
To meet these goals, a recirculating textile filter system was constructed; hydraulic loading rates
and recirculation rates on the recirculation system were adjusted to ensure complete nitrification,
and a denitrification unit was added in the treatment chain (Figure 2). This last unit receives a
carefully balanced mix of septic tank effluent and nitrified water to be denitrified before final
disposal. The septic tank effluent serves as carbon source for the denitrification process.
The hydraulic profile of the wastewater treatment process is shown in Figure 3. The raw
wastewater is first collected in a community septic tank where solids settle thus reducing the
organic load. Anaerobic digestion of the settled solids reduces their volume and allows for long-
term accumulation before the tank needs to be emptied. Two biotube effluent filters are installed
in the tank near the outlet; the effluent filters capture non-settleable solids that would otherwise
be carried forward with the effluent.
With the effluent filters, there are two pumps that pump the clarified effluent in part to the
recirculating textile filter tank (RTF tank) and in part to the denitrification textile filter tank

(DTF tank). The RTF tank also receives a portion of the water filtered on the recirculating textile
filter (RTF) and all the water from the denitrifying textile filter (DTF).
For this project, a recirculation rate on the RTF of 5,5:1 was chosen. At this recirculation rate,
the septic tank effluent is filtered on the RTF 5,5 times before it is removed. The filtered water is
split between disposal (1 Q), and the DTF tank (4,5 Q). The water sent to the DTF tank is dosed
on the DTF with a recirculation rate of 5:1 and then returns to the RTF tank, thus completing the
treatment cycle.
The septic tank is designed for a theoretical detention time of 2,25 days. In the tank are located 2
biotube effluent filters and 2 pumps that are controlled by a timer. A set of floats signal high and
low water levels.
The RTF tank has an effective volume 47,6 m3, i.e. 106% the design flow. In the tank are located
four pumps that send the water to the RTF, and a splitter valve that splits the water filtered on the
RTF between disposal and the DTF tank. A timer incorporated in a duplex control panel controls
the pumps. A set of floats indicates high and low water levels in the tank.
The RTF is designed on a 80 cm/d hydraulic loading rate. It measures 56,9 m2 and is made of
three 15-cm layers of textile coupons. A low-pressure distribution system feeds water uniformly
on the surface of the bed. Filtered water is collected at the bottom by a collection pipe.
The DTF tank is a 25 m3 (effective) concrete reservoir. This tank is smaller than the RTF tank
because it need not absorb peak flows. In this tank are located one pump that doses the water on
the DTF. A timer incorporated in a simplex panel controls the pump; a set of floats indicates high
and low water levels.
The DTF is designed on a 100 cm/d hydraulic loading rate and has a 45-m2 surface area. A low-
pressure distribution system distributes water on the surface of the filter. The filter is a 50-cm
bed of textile coupons. At the bottom, two pipes collect the filtered water. This filter is kept
saturated by a level control device. A backwash system is also provided.
The Kirkvine plant wastewater treatment system is operational since July 1998. Phase one of the
start-up was limited to the RTF cycle. Adjustments were made to ensure proper operation of the
system. Daily flows and system performance were monitored; causes of excessive wastewater
flows were identified and corrected. Phase two of the start-up concerns the DTF cycle.

Conclusion
Intermittent filters offer attractive wastewater treatment solutions for small flow systems. They
are a well-known and widely spread class of technology in North America. Intermittent filters
are low-cost systems that are easy to operate, take little space, and provide high quality
treatment. They are flexible treatment chains that could incorporate complementary treatment
phases such as denitrification, phosphorus removal and disinfecting.

The textile filter options are particularly interesting when granular material is not easily
available. Furthermore, the textile filters take less space than the granular beds: a residential unit
occupies as little as 4 m2 while larger systems require 25 times less space than a conventional
leachfield. They offer a treated effluent quality with BOD5 and TSS values below 15 mg/L or
less, and faecal coliform counts less than 50 000.
The Kirkvine wastewater treatment plant is an example of how these technologies can be
implemented locally.

Small Community Wastewater Treatment Systems In The Wider
Caribbean
Francine Clouden
BSc. Sanitary Engineer, Caribbean Environmental Health Institute, PO Box 1111,
The Morne, Castries, St. Lucia
Tel: (758) 452-2501, Fax: (758) 453-2721, Email: fclouden.cehi@candw.lc

Background
The increased supply of potable water together with the growing standard of living and increased
industrialization in the Caribbean, including tourism, has resulted in more and more liquid waste
(i.e. wastewater) to be disposed of. Considerable attention is therefore now being paid to liquid
wastes in nearly all Caribbean countries. Following from this is the realization that liquid wastes
are a major source of land-based pollution of the marine environment and therefore pose a
significant threat to the integrity of the fragile ecosystems on whose survival the tourist based
economies depend.
In most of the countries there is uneven distribution of inhabitants. There is a tendency for the
population to be concentrated on the coastal belt because of the need to be close to port facilities,
fishing grounds and manufacturing and tourism activities.
In Caribbean countries the capital city is the focus of economic and service activity. There are
usually a few additional important centres where populations are concentrated. In many instances
there is also development in the suburban periphery and continuous linear patterns of settlement,
especially along the coast. The remainder of the population is found in towns, villages and
tenantries of varying size.
Providing municipal wastewater treatment for these mainly decentralised communities thus
presents a significant challenge to Caribbean Governments.
Sewer systems, exist in some Caribbean countries (e.g. Barbados, Grenada, Trinidad, St. Lucia)
In 1991 it was estimated that 10% of the population in the Caribbean is connected to some form
of sewer system. Some systems are old, undersized and in need of repair, and many discharge
without prior treatment into rivers or the marine environment. New systems are planned in
Roseau, Dominica, and the south and west coasts of Barbados. These systems, however, tend to
require large capital investments and the planning and implementation stages are very long.
There are also numerous small or package plants that are operated by both the public and private
sector
By far, the most widely used system of sewage disposal, especially in the urban and peri-urban
areas, is the septic tank and soakaway, and in the coral islands like Barbados, the suck well,
which is a deep pit to facilitate percolation. In areas where soil conditions do not permit proper
infiltration, effluent is generally disposed of in street drains. Many rural communities, especially

those without access to piped water supplies, depend upon pit latrines, and the provision of
public facilities for wastewater treatment or excreta disposal.

Wastewater Treatment Technologies
Relatively simple wastewater treatment technologies for small communities can be designed to
provide low cost sanitation and environmental protection, as well as provide additional benefits
such as reuse of treated wastewater. These systems may be classified into three principal types,
as shown in Figure 1.
Oxidation
Ditch
Mechanical
Extended
Aeration
Sequencing
Batch
Reactor
Trickling
Filter

Free water surface
Facultative

Subsurface flow

Aquatic

Water Hyacinths

Aquaculture
Aerated
Duckweed

Intermittent

Sandfilters

Recirculating

Slow-rate
Terrestial
Overland flow
(discharge)
Rapid infiltration

Subsurface Infiltration

Figure 1. Summary of Wastewater Treatment Technologies

Mechanical Systems
Mechanical systems utilize a combination of physical, biological, and chemical processes to
achieve the treatment objectives. Using essentially natural processes within an artificial
environment, mechanical treatment technologies use a series of tanks, along with pumps,
blowers, screens, grinders, and other mechanical components to treat wastewaters. Sequencing
batch reactors, oxidation ditches, extended aeration systems, and contact stabilisation systems are
all variations of the activated-sludge process, and are all used with varying success throughout
the region, where land is a premium. Most are privately owned and operated, e.g. at hotels,
however some communities, most recently in Montserrat do utilise them.

Suitability
These systems are more suitable for places where land availability is a concern, such as
residential areas. Both the capital and operational and maintenance costs are generally higher
than for the other technologies (depending on the cost of land), but they do afford greater
operational control, given that specialized personnel for their operation are available. These
systems are designed to meet the limits generally established for secondary treatment (BOD and
SS < 30 mg/l) and can also provide advanced treatment.
A study done by CEHI/PAHO in 1991, found that 75% of these "mechanical" type systems were
not reaching the minimum generally accepted standards for operation. This was attributed to (1)
the use of "high-tech" technology which was not adapted for use in the region; (2) limited
understanding of treatment processes by operators; and (3) insufficient time and budget
allocation. Recommendations for improvement would include (1) the use of equipment and
materials which are locally available; and (2) formal training and eventually certification of
operators. Additionally only 16% of the plants surveyed had a trained operator, while a full-time
operator was available at only 20% of the plants.

Aquatic Systems
Facultative lagoons are the most common form of aquatic treatment lagoon technology currently
in use. The term `facultative' refers to a mixture of aerobic and anaerobic conditions, and in a
facultative pond aerobic conditions are maintained in the upper layers, while anaerobic
conditions exist towards the bottom. The intermediate layer is aerobic near the top and anaerobic
near the bottom, and constitutes the facultative zone. Aerated lagoons are smaller and deeper
than facultative ponds and evolved from stabilization ponds.
Constructed wetlands, aquacultural operations are generally very efficient ways to polish a
treated wastewater effluent. Constructed wetlands can be utilised in two ways; sub-surface water
flow, and surface water flow. These systems use the roots of plants to provide substrate for the
growth of attached bacteria which utilize the nutrients present in the effluents, and for the
transfer of oxygen. Bacteria do the bulk of the work, although there is some nitrogen uptake by

the plants. Typically these systems are long, narrow basins, with depths of less than 2 feet, that
are planted with bulrushes or cattails. The surface water system most resembles a natural
wetland. The shallow groundwater systems use a gravel or sand medium, which provides a
rooting medium for the aquatic plants through which the wastewater flows.
Aquaculture systems are distinguished by the type of plants grown in the wastewater holding
basins. These plants are commonly water hyacinth or duckweed. These systems are basically
shallow ponds covered with floating plants that detain wastewater at least once per week. The
main purpose of the plants in these systems is to provide a secure habitat for bacteria which
remove the vast majority of dissolved nutrients. Tables 1 and 2 summarise the design features of
these systems.
Table 1. Typical Design Features for Aquatic Treatment Units
Technology
Treatment Goal
Detention Time
Depth (feet)
Organic Loading
(days)
(lb/ac/day)
Oxidation pond
Secondary
10-40
3-4.5
36-110
Facultative pond
Secondary
25-180
4.5-7.5
20-60
Aerated pond
Secondary,
7-20 6-18 45-180
polishing
Storage pond
Secondary, storage,
100-200 9-15 20-60
polishing
Root zone
Secondary 30-50
<4.5
<45
Treatment Hyacinth
pond
Table 2. Typical Design Features for Constructed Wetlands
Design Factor
Surface Water Flow
Subsurface Water Flow
Minimum Surface Area
23-1 IS ac/mgd
2.3-46 ac/mgd
Maximum water depth
Relatively shallow
Water level below ground surface
Bed depth
Not applicable
12-30 in.
Minimum hydraulic residence time
7 days
7 days
Minimum pretreatment
Primary (secondary optional)
Primary
Range of organic loading as BOD
9-18 lb/ac/d
1.8-140 lb/ac/d

These systems are being used to a small extent in the region. Two hotels (one in St. Lucia, the
other in Grenada) are currently using aquaculture systems, utilizing the water hyacinth, with
reasonable success. CEHI as recently as 1995 completed a design for a constructed wetland at
another hotel in St. Lucia, (which has not been constructed to date) and has given preliminary
advice to a third on a similar system. The University of the West Indies, Mona, Jamaica is
currently operating a pilot system.

Suitability
Natural treatment systems are capable of producing an effluent quality equal to that of
mechanical treatment systems, and can meet the secondary treatment limits. These systems are
extremely applicable where there is plenty of land available, and where suitable aquatic plants
grow naturally. Most advantages of this system relate to their "low-tech/no-tech" nature, which
means that these systems are relatively easy to construct and operate, and to their relatively low
cost, which makes them attractive to communities with low budgets. However their simplicity
and low cost may be deceptive in that the systems require frequent inspections and constant
maintenance to ensure smooth operation. Concerns include hydraulic overloading, excessive
plant growth, and the fact that they can produce effluents of variable quality depending on time
of year, type of plants, and volume of wastewater loading.

Terrestrial Treatment Technologies
These include slow-rate overland flow, slow-rate subsurface infiltration, and rapid infiltration
methods, which are used for further polishing. Additional benefits are the yielding of water for
groundwater recharge, reforestation, agriculture, and/or livestock pasturage. They depend upon
physical, chemical, and biological reactions on and within the soil. In slow-rate systems, either
primary or secondary treated effluents are applied at a controlled rate to a vegetated land surface
of moderate to low permeability. The wastewater is treated as it passes through the soil by
filtration, adsorption, ion exchange, precipitation, microbial action, and plant uptake. Vegetation
is a critical component of the process and serves to extract nutrients, reduce erosion, and
maintain soil permeability.
Slow-rate subsurface infiltration systems (e.g. soak-away) and rapid infiltration systems (e.g.
suck-wells in Barbados) are "zero-discharge systems" that rarely discharge effluents directly to
streams or other surface waters, but can recharge groundwater aquifers. In overland flow systems
the effluents are eventually discharged to surface water. The main benefits of these systems are
their low maintenance and low technical manpower requirements.

Suitability
Sub-surface infiltration systems are designed for municipalities of less than 2,500 people. They
are usually designed for individual homes, but can be designed for clusters of homes. Although

they do require specific site conditions, (see Table 3) they can be low-cost methods of
wastewater disposal.

Table 3. Site constraints for Land Application Technologies
Feature Flow
Slow Rate
Rapid
Subsurface
Overland
Infiltration
Infiltration
Soil Texture
Sandy Loam to Clay Loam
Sand and Sandy
Sand to Clayey
Silty Loam and
Loam
Loam
Clayey Loam
Depth to
3 ft
3 ft
3 ft
Not
Groundwater
Vegetation Required
Optional Not
Applicable Required
Climatic
Growing season
None
None
Growing Season
Restrictions
Slope
<20%, cultivated land
Not Critical
Not Applicable
2% - 8% Finished
Slopes
<40%, uncultivated land
Source: USEPA, Wastewater Treatment/Disposal for Small Communities. Cincinnati, Ohio, 1992. (EPA
Report No. EPAZ25/R-92 005)

Excreta Disposal Technologies
Many small communities in the Caribbean do not have wastewater collection or treatment
systems, especially where potable water supply is limited. The challenge in this case is to
provide an adequate system for excreta collection, disposal and possibly treatment at another
location. Some of the more common systems are outlined below.

Pit Latrines
Pit latrines are the simplest and most widely distributed disposal plants for excreta. They can be
utilized not only in rural/rustic areas, but also in municipal districts. These plants are at the same
time the cheapest systems for any self-help programs.
A simple pit latrine. The excreta falls directly into an excavated pit which normally is neither
consolidated or lined with brickwork. All liquids like urine, cleaning water, etc. can seep into the
subsoil. The solid substances are retained and will gradually fill up the pit. As soon as two-thirds
of the pit is filled, it either has to be emptied or a new pit dug.

Modifications to this simple pit latrine include the ventilated improved (VIP) latrine, with or
without offset pit; the water-flush or pour-flush latrine.

Planning Aspects
The following factors have to be taken into consideration when designing pit latrines:
1. Population density
2. Groundwater level
3. Consistency of the subsoil
4. Water pollution

Institutional Aspects
The construction of pit latrines is quite simple and should therefore be carried out as far as
possible by self-help. The biggest problems are encountered in areas where latrines had
previously been unknown, or previous systems had not functioned well. In some peri-urban areas
there may also be a social stigma attached to pit latrines.
In these cases the local administration should mount a public awareness and education
programme outlining the needs and benefits of the systems, how they should be used effectively,
and measures regarding the design standards, credit terms and financing. The installations should
be checked several times to inspect utilization and maintenance.

Composting Toilets
In principle there are two different types of composting toilets.
Batch composting toilets are usually built up with a two-pit system. As soon as one pit is filled
up to two-thirds, it is topped up with earth and closed, the second one is then used. When the
second one is filled up, the first one has to be emptied and put into service. This type of toilet
provides an anaerobic composting.
For continuous composting only one pit is required and it must be completely bricked up. All the
excreta, grass, straw, sawdust ashes etc. fall onto the grates, which are spaced by narrow slits and
compost there. The digested materials finally fall into the humus pit and have to be removed at
regular intervals. These systems do have high maintenance expenditure, and it has not been
completely established under what conditions the composting process could proceed in the best
possible way. They are generally not recommended for use in the tropics.

Aqua privies and Septic Tanks
In the absence of public disposal installations, septic tanks, besides pit latrines are the most
common installation for simultaneous disposal of excreta and household wastewater. These tanks
have the distinct advantage that they can be connected later on to any public network. The tank
will then serve for a certain preliminary treatment preventing a large quantity of solids from
flowing into the sewerage system (see Alternative Collection Systems).
Aqua privies generally have a lower purification capacity than septic tanks. They consist of one
compartment which is dimensioned on the basis of 0.12 m3 per user, with a maximum capacity
of 1m3. This means that sludge must be removed every 2 to 3 years. If there is a sufficient water
supply and/or sewerage possibilities, for hygienic reasons preference should be given to the
septic tank.

Bucket Latrines/Vault Toilets
The design of toilets with collection pits (vault toilets) resembles in general that of the pour-flush
toilet. Construction costs are low, as no excavation work is involved, Space requirements are
small, and this is the main reason why such plants are frequently built in densely populated areas.
The excreta must then be disposed of either individually, by the user, or through a community
collection and disposal system (which is preferred). This type of system has many health risks
inherent in it. The buckets can easily overflow and pollute the environment and expose users to
disease causing organisms. Buckets must also be kept clean after being emptied to reduce the
attraction of flies and other vectors.
This system is currently in use in at least two villages in St. Lucia, with varying success, as
discussed in a later section.

Communal Sanitation Facilities
These are facilities built in blocks and installed in central areas. As a rule they are connected to
septic tanks which are designed according to the number of toilets and equipped with running
water. They may also provide showering and laundering facilities.
There are generally two types of communal facilities
1. Blocks which are used only by a certain number of families
2. Common installations which are frequented by all inhabitants of a community depending
on their need.
The latter is what commonly obtains in the Caribbean.

Alternative Collection Systems
Small diameter gravity sewers are rapidly gaining popularity in unsewered areas because of their
low construction costs. Unlike conventional sewers, primary treatment is provided at each
connection (septic tanks), and only the settled wastewater is collected. Grit grease and other
troublesome solid which may cause obstructions in the collector mains are separated form the
main wastewater flow and retained in interceptor or septic tanks installed upstream of each
connection. With the solids removed, the collector mains need not be designed to carry solids as
conventional sewers must be.
Large diameter pipes designed with straight alignment and uniform gradients to maintain self-
cleansing velocities are therefore not necessary. Instead the collector mains may be smaller in
diameter and laid with variable or inflective gradients. Construction costs are reduced because
SDGS may be laid to follow the topography more closely than conventional sewers and routed
around most obstacles in their path without installing manholes.
Such a system had been considered for a rural community in St. Lucia, but was never fully
designed or constructed.

An Exercise in Appropriate Technology � Case Study of a Typical Village in St.
Lucia
The village is located on the East Coast of St. Lucia. The soil type is extremely rocky in
some areas and the ground water table is high, as the main part of the villages is located in
a flood plain close to the ocean. Houses are located very close to each other and the
development is random and unplanned.
The total population of the village is 4440 (1992 census) with a total number of households of
1179.
St. Lucia Water and Sewerage Authority (WASA) supplies the potable water, with intakes
located in the vicinity. Treatment consists of a stone filter, sand filters (in parallel), and
chlorination. 23% of the population are supplied by standpipes in the neighborhood, 50% have a
private supply (i.e. piped water in the home) and 27% have none available close by i.e. no
standpipe within walking distance. Because of the topography regularity of the supply is
compromised.
Current excreta disposal practices are as follows: 11% pit latrines; 13% pail latrines; 34% water
closet and septic tank; 42% none on premises. This forty-two percent of the residents (600
persons) use the public facilities provided of which there are five with a total of 22 toilets and 24
showers operational.
Most of the facilities were built 15 to 20 years ago and include showering and laundering
facilities. All the facilities operate with the same system. The grey water is discharged either
directly into the sea or into a surface drain that runs into the sea. Excreta ("black water") is

treated in a septic tank. The effluent from the septic tank is disposed of into a soakaway through
a pipeline. A pump truck is used to remove the sludge remaining in the septic tank. The
regularity of this is dependent on the availability of the pump truck, which is sporadic due to
frequent breakdowns.
At one of the facilities located at the beach the use of the toilets was discontinued in order to
avoid pollution caused by a crack in the pipe of the septic tank and the proximity of the
corresponding soakaway to the sea. Bathing in the 4 shower rooms and laundry is still practiced
and the grey water goes directly into the sea.
The newest facility, built in 1994, near the fishing port of the village is in comparatively good
condition. It is equipped with 8 toilets and 8 shower rooms. As the caretaker reported the only
problem encountered is frequent breaking of the toilets cisterns because domestic fittings have
been used.
Another facility is elevated, therefore some problems are encountered with its water supply. At
certain times, especially in the morning the water supply fails in the whole facility.
The remaining two facilities are working well. Both are centrally located, where most of the
houses have no private amenities.
Moreover the two facilities at the beach have night soil chutes to prevent the residents from
throwing their night soil into the river. Unfortunately the use of the night soil chutes had to be
discontinued due to the residents disposing of solid waste into them. This led to frequent choking
which caused the maintenance cost to rise. Additionally, the instruction board for proper use of
the chutes has gone missing from one of the facilities.
Most of the public facilities have in common that they are not maintained properly, have often
fallen into disrepair and are subject to vandalism by the residents.
The result of most of these problems is that the village has a high incidence of diarrhea and other
enteric diseases such as Typhoid Fever and Dysentery. A recent survey (stool examinations)
revealed that 65% of the school age children in the village were infested with some type of
Helminthes. Monitoring of the potable water supply over a two-and-a-half week period during
the rainy season showed that the quality of drinking water was quite good. The conclusion may
be drawn therefore that poor sanitation, hygiene and excreta disposal are the main causes of the
high incidence of disease.
The systems currently being used in the village are all deemed "appropriate technology" yet they
still failed. The information just presented suggests that the problem in the village cannot be
solved solely by a technical approach such as construction of Pit Latrines or improvement in
water supply. It would be relatively simple to recommend and design such. Other short-term
solutions such as repair and rehabilitation of public facilities can also be implemented but a more
holistic approach involving all stakeholders needs to be adopted. The previous failure of the
other projects, such as the night soil chutes and the lack of regard of residents towards the public
facility need to be examined and addressed before any solution can be successfully implemented.

The practices of the reverting to using the bushes or rivers when the water supply is bad indicates
a general lack of understanding on the part of residents of basic sanitation and hygiene issues,
and their link to the incidence of illness and diseases.
We can therefore conclude that the term "appropriate technology" should refer not only to the
technical solution but should encompass a complete system that addresses social, cultural and
economic issues.

References
Clouden, F; Joel, D; Singh, J; Wastewater Treatment and Excreta Disposal in Tropical Rural
Areas � A Case Study of Health Implications
GTZ/GATE; Wastewater Treatmnent and Excreta Disposal in Developing Countries; March
1980
Mara, D; Sewage Treatment in Hot Climates;
PAHO/CEHI; Assessment of Operational Status of Wastewater Treatment Plants in the
Caribbean; December 1992
Sweeney, Vincent; Wastewaters and their Treatment in the Caribbean; July 1995
Sweeney, Vincent and Kraft, Harald; Rootzone Wastewater Treatment in St. Lucia; April 1995
UNEP; Sourcebook of Alternative Technologies for Freshwater Augmentaion in Latin America
and the Caribbean
USEPA; Alternative Wastewater Collection Systems
USPA; Wastewater Treatment/Disposal for Small Communities; September 1992

Decision-making Software and Information Systems:

"maESTro"
Vicente Santiago Fandino
Programme Officer, Shiga Office, 1091 Oroshimo-cho, Kusatsu City, Shiga 525-0001, Japan
Tel: (81-77) 568-4585, Fax: (81-77) 568-4587, Email: vstiago@unep.or.jp

Introduction
a. UNEP International Environmental Technology Centre (IETC)
IETC's main role is to promote the application of Environmentally Sound Technologies (ESTs)
to address urban environmental problems, such as sewage, air pollution, solid waste and noise,
and the management of freshwater basins in developing countries and countries with economies
in transition. The Centre serves as a proactive inter-mediator for cooperation between sources
and users of ESTs.

b. Definition of ESTs
Environmentally Sound Technologies (ESTs) encompass technologies that have the potential for
significantly improved environmental performance relative to other technologies. Broadly
speaking, these technologies protect the environment, are less polluting, use resources in a
sustainable manner, recycle more of their wastes and products, and handle all residual wastes in
a more environmentally acceptable way than the technologies for which they are substitutes.
Furthermore, as argued in Chapter 34 of Agenda 21, ESTs are not just "individual technologies,
but total systems which include know-how, procedures, goods and services, and equipment as
well as organizational and managerial procedures". Consequently, when considering technology
promotion, IETC's approach incorporates both the human resource development (including
gender relevant issues) and local capacity building aspects of technology choices. ESTs should
also be compatible with nationally determined socio-economic, cultural and environmental
priorities and development goals.
Information on ESTs, however, is often hard to obtain in a
standardized, user-friendly format. To solve this problem, IETC
created a searchable electronic EST-directory, called maESTro.

maESTro - EST Directory
a. What is maESTro?
maESTro is an information tool that links providers of environmental technology with potential
users. maESTro's database contains more than 1500 worldwide information on a full range of
environmental technologies, institutions and information sources including air and water
pollution, environmental management, human settlements, recycling toxic substances, solid
waste, wastewater, water augmentation and more. The information is regularly updated by IETC
as well as EST contributors, individual users, organizations and institutions.
maESTro was first developed as a tool to disseminate information on Environmentally Sound
Technologies (ESTs) on floppy disks, CD-ROMs and hard- copy format for free of charge. In
March 1998, in response to maESTro user's request, IETC has decided to further develop
maESTro on the worldwide web so that people can access through the Internet. The newly
developed web-maESTro can be found at the EST Directory on IETC's homepage
(http://www.unep.or.jp).
The purpose of the database is to be used as a directory of environmental technologies and to
present as many options as possible. The user should then contact the technology
owners/institutions/information sources and obtain additional data.

b. EST Contributors
Since 1996, maESTro has been honored to partner with numerous government ministries,
including the Ministry of Environment in New Zealand, the Ministry of Nature & Environment
in Mongolia, the Ministry of Environmental Protection in Lithuania, the Ministry of
Environment & Forests in India, the Ministry of Housing, Municipality & Environment in
Bahrain, the Ministry of Environment in Lebanon, the Ministry of Energy & Mines in Eritrea,
and the Ministry of Environment of the Republic of Korea.
Efforts have been focused on negotiating with potential environmental information contributors
in both the public and private sector to develop the exchange of EST-related information. Among
the numerous contributors to maESTro have been UNIDO and GEC (Global Environment Centre
Foundation) in Japan, EPA (Environmental Protection Agency) in the United States, and
OCETA (Ontario Centre for Environmental Technology Advancement) in Canada (see Table 1).

Table 1. EST Contributors
A
Argentina
- Mr. Eduardo Sendra, Instituto de Limnologia Dr. Raul Ringuelet
Austria
- Mr. Peter Pembleton, UNIDO
C
Canada
- Mr. David Pederson, Corporations Supporting Recycling ( CSR)
- Prof. Ray Cote, Dalhousie University
Chile
- Ivan Tobar Guerrero, INTEC
Colombia
- Mr. Edgar Castillo, Universidad Industrial de Santander
Czech
- Mr. Daniel Svoboda, AGSS Ltd

Ecuardo
- Mr. Marco Encalada, Corporcion Okios
Egypt
- Dr. Mohamed A.E. Badri, University of South Valley
G
Germany
- Dr. Jorg. W. Fromme, International Transfer Centre for Env*tal
Technology (ITUT),
Greece
- A.I. Zouboulis, Aristotle University
H
Hungary
- Mr. Zsolt Istvan, Bay Zoltan Foundation for Applied Research
Institute of Logistics and Production Systems
I
India
- Dr. D. Narasimha Reddy, Centre for Resource Education (CRE)
- Mr. Harjit Singh, Ministry of Environment and Forests
- Mr. Vadim Kotelmikov, APCTT
J
Japan
- Mr. Kaoru Sasabe, Ministry of Construction
- Mr. Shinichi Arai, Global Environmental Centre Foundation

- International Environmental Technology Center
- Mr. Yoshio Shimazu, ILEC (International Lake Environment
Committee)
- Ms. Kani Keiko, International Centre for Environmental
Technology Transfer (ICETT)
Jordan
- Mr. Ayman Al-Hassan, Royal Scientific Society
K
Kenya
- Ms. Maria Arce, Environment Liaison Centre International
(ELCI)
Kiribati
- Mr. Eita Metai, Work & Energy
Korea
- Mr. Sang-Ho Lee, Korea Institute of Industry & Technology
Information
- Mr. Younghan Kwon, Korea Environmental Technology
Research Institute (KETRI)

L
Lybia
- Dr. M.A. Muntasser, International Energy Foundation
M
Malaysia
- Mr. Goh Kiam Seng, Centre for Environmental Technologies
(CETEC)
P
People's Republic - Ms. An Tong, National Environmental Protection Agency
of China
(NEPA)
- Ms. Jiang Xiaoyu, China Association of Environmental
Protection Industry
- Prof. Huang Xia, Tsinghua University
Philippines
- Mr. Danilo G. Lapid, Centre for Advanced Philippine Studies
Poland
- Ms. Beata Michaliszyn, Institute for Ecology of Industrial Areas
S
Switzerland
- Annette Pruss, World Health Organization
- Dr. Niklaus Klaentschi, EMPA, Swiss Federal Laboratories for
Materials Testing and Research
- Mr. Dieter Koenig, UNCTAD
T
Thailand
- Ms. Lilia R. Austriaco, Asian Institute of Technology (AIT)
U
Ukraine
- Mr. Anatoliy I. Salyuk, Ukrainian State University of Food
Technologies
United States of
- Mr. William McSpadden, Global Environment & Technology
America
Foundation
- Dr. Nicholas Ashford, MIT
- Tad McGalliard, Work & Environment Institute
United Kingdom
- Dr. Chris Watts, WRc
Uruguay
- Mr. Alexis Ferrand, Environmental Management Secretariat
(EMS)
c. Data in maESTro
All information collected and disseminated through maESTro remain under the full
responsibility of the original source of information. No guarantee is given, nor responsibility
taken by IETC for errors or omissions in the Directory, and IETC does not accept liability for
any information or advice given in relation to or as a consequence of data contained in our
information system.
IETC's mandate is to function as proactive intermediator between providers and users of ESTs
and/or related information by bringing together all interested parties. IETC does not endorse
particular technologies disseminated through this Directory as environmentally sound. That is the
discretion of maESTro users.

d. maESTro Categories

The data in maESTro are categorized into three fields: Technology, Institution, and Information
System (Figure 1).
- Technology: "hard"4, "soft"5 and indigenous6 environmental technologies in the world.
- Institution: a compilation of currently about 460 institutions worldwide dealing with ESTs
- Information System: information tools (i.e. data bank, directory) that supply information on
ESTs
Users can browse the information through three query parameters: keywords (wastewater,
treatment, etc.), geographical location and INFOTERRA themes.

Dissemination of Information through maESTro
maESTro is available on- line through the Internet. For those who
do not have access to the Internet, IETC provides maESTro in the
form of CD-ROM (called PC maESTro), floppy disks and/or hard-
copy format on specific issues.
a. Hard-Copy Format
Hard-copy format of maESTro is provided to users upon their requests free of charge (Figure 2).
The hard- copy maESTro includes: Preface, Table of Contents, EST directories on the request,
and Index by INFOTERRA themes and Location.

b. CD-ROMs and Floppy Disks
maESTro is also available in CD-ROMs and/or floppy disks
(Figure 3). Users can browse, modify, insert, import and export
data with their PCs. The system is user-friendly, and with just a
click on the mouse, the information appears in a standardized
format called Directory Interchange Format (DIF). Through DIF,
maESTro is fully compatible with major international databases
such as UNEP's Global Resources Information Database (GRID),
NASA, CEOS and NASDA.
The information in CD-ROMs and floppy disks is regularly updated by IETC, and the latest
version of CD-ROMs and floppy disks are provided to registered users free.

4 Hard technologies include equipment(s) and devices(s); i.e. water treatment and supply technologies, sewage and
waste treatment facilities, ground remediation technologies and pollution monitoring equipment.

5 Soft technologies refer to planning and management techniques (such as Environmental Technology Assessment,
Risk Assessment and Environmental Auditing) that provide the contextual framework within which "hard"
technologies should be understood.

6 Indigenous technologies refer to the traditional technologies produced by local communities in a given
environment

c. Internet (web-maESTro)
The web-maESTro enables all Internet browsers to log in for free anytime in search of
environmental information and to browse the latest data in a timely and direct fashion
(http://www.unep.or.jp/maestro/). The data is updated on the daily basis by IETC. Furthermore for the
better understanding, images are attached to some information.
Although registration is not mandate, IETC recommends users to register into maESTro for their
convenience (registration is free). Followings are the advantages entitled to the registered users.
- Personalized information
On the welcome page of maESTro, you will see how many new and
updated information has been entered since your last visit.
- Notification by e-mail
For your convenience, whenever there is a major change in maESTro system,
you will be notified by e-mail.
- Insert and modify the data
Users can Insert and modify their own information into the maESTro
database. Users who have inserted new data can keep, preview, modify and
delete their data in the Personal Database until the data is completed
satisfactorily and is ready to be sent to IETC for verification.
Furthermore, maESTro offers a working group facility that enables users and their partners to
work together using network system. This means that users can share, view, and modify
information from different users in the same working space.

Benefits for maESTro Users
� Free of Charge
Through maESTro, users are able to become part of IETC's EST-directory for
free. This directory is growing rapidly through increased number of IETC's
networking partners as well as individual Internet users in the world. As more and
more maESTro becomes widespread, information exchange will become more
feasible.
� Global Networking
All the users (individuals, organizations and companies) can browse, insert and
modify their own data at their own location through web, e-mail, and/or mail
(floppy disks for those without Internet access). The data inserted by users will be
verified by IETC and soon be disseminated globally through maESTro.

Contributions to maESTro
All information in maESTro will be continuously amended and updated. For this purpose,
technology owners and other interested institutions are welcomed to add their EST information
on ESTs to this EST Directory. Assisted by maESTro, each institution can manage their internal
information collection and exchange. All entries made will be accessible throughout a global
network of EST information suppliers and users, and also linked to UNEP/IETC Homepage for
Internet browsers.
Please address your queries and requests regarding maESTro to:
UNEP/IETC Shiga Office
Oroshimo-cho, Kusatsu City,
Shiga, 525-0001, Japan
Tel: +81 775 68 4580
Fax: +81 775 68 4587
E-mail: maestro@unep.or.jp
URL: http://www.unep.or.jp/maestro/
__________________

WAWTTAR
Christopher McGahey, Ph.D.
USAID/Jamaica Coastal Water Quality Improvement Project (CWIP), USAID Environmental Health
Project (EHP), ARD Inc.
110 Main Street, Fourth Floor, Burlington, Vermont 05401, cmcgahey@ardinc.com

Introduction
The WAWTTAR program was designed to assist financiers, engineers, planners and decision-
makers in improving their strategies toward sustainable water and sanitation coverage while
minimizing impacts on water resources. The program is built upon the concept that when
equipment or technology is supplied, access to repair parts and resources for operation and
maintenance are available. This includes having materials, equipment and trained operators to
ensure that the environmental and financial investments are protected.
Involvement of the target population from the early stages in a water supply and wastewater
treatment project is crucial for long-term success. Local decision-makers at all levels need to
understand the basic principles of the various processes and support the ideas introduced. The
WAWTTAR program is intended to be used as a tool to support effective decision-making. It
was developed specifically for application at the pre-feasibility stage of project development to
assist planners select suitable water and wastewater treatment processes which are appropriate to
the material and manpower resources available in their particular location at particular times. The
breadth of coverage of the software is aimed at eliminating the problem of overlooking
applicable treatment processes and minimizing system failures due to installation of
inappropriate treatment technologies.
The WAWTTAR program is intended to be applied in the early evaluation of potential
infrastructure investments in the areas of water treatment, wastewater treatment and water
reclamation. The program is designed to assist decision-makers dealing with the following types
of issues:
1. Identification of the least-cost treatment scheme for a community with site-specific socio-
economic and geographical conditions;
2. Presentation of risks to long-term sustainability of selection of identified treatment
schemes;
3. Collection of viable combinations of technologies available to a specific community to
meet water reuse standards or guidelines;
4. Identification of least-cost wastewater collection and treatment options for high-density,
peri-urban communities;
5. Balancing of coverage and risk for selection of treatment schemes within financial
constraints;
6. Selection of technologies to meet particular water quality and/or reclamation standards;
and

7. Sensitization of decision-makers to the issues of sustainability related to water, sanitation,
wastewater and/or water reuse.

Technology Selection
The main use of WAWTTAR is as a tool for individuals with a technical background to screen
and investigate possible water and wastewater treatment options. It enables the user to
accomplish this by examining the public health status, water resource requirements, material
availability, cost structures and ecological conditions which exist in a particular community. The
program assesses these combined factors to generate a set of comparable and refinable feasible
technical solutions.
WAWTTAR incorporates innovative and alternative technologies and emphasizes water reuse as
an integral component of treatment schemes. WAWTTAR does not, however, exclude
conventional options and is of equal usefulness in the screening and examination of such options
as well. The main application of WAWTTAR is in technology assessment and evaluation for
urban population centers with significant human, material and financial resources available for
infrastructure improvement. In most of these urban centers, access to adequate sanitation is
typically available for most residents through sewers or individual septic tanks.
For many others, especially those living in peri-urban zones, residents are typically without
acceptable wastewater collection and treatment systems. What systems do exist in these
communities generally follow conventional designs although alternative systems may be
applicable. WAWTTAR has also been designed to account for the particular, non-conventional
wastewater collection and treatment systems which are applicable to these types of settings.

Operation of WAWTTAR
WAWTTAR requires an IBM-PC compatible computer running Microsoft Windows 95 or later.
Thirty-two MB of RAM and a minimum graphics resolution of 800x600 with 256 colors are
required to run the program. Depending upon individual computer configuration, between 30 and
40 MB of disk space are required to install WAWTTAR. It is intended to be installed on a
computer from a CD-ROM disk.
In the basic operation of WAWTTAR, fundamental parameters such as performance standards,
material costs, raw water or wastewater quality, community needs and capabilities, and planning
horizons are entered by the user into easily editable data fields. The user then constructs several
possible sequential treatment schemes from a comprehensive list of available treatment processes
contained in the software program. WAWTTAR first screens these options according to the
needs, capabilities and resources of the community in question, and it discards those options
which are infeasible. WAWTTAR then calculates the performance, construction costs and
operations and maintenance costs of the remaining viable treatment schemes. These calculations
are based on simple mathematical models of each of the treatment processes. Feasible options
can then be compared based on performance and annualized costs.

For each infeasible treatment scheme, WAWTTAR displays the reasons for infeasibility. The
user can, therefore, analyze infeasible treatment schemes for deficiencies and reassess or vary the
criteria which led to failure. These deficiencies can be corrected and the cost and performance of
the corrected system can be calculated for consideration against other feasible alternatives.
WAWTTAR is not a dynamic program and does not directly analyze the response of a given
system to, for example, variable influent conditions. Sensitivity to varying influent values must
be explored by multiple trials of treatment systems with different influent qualities. WAWTTAR
also does not assemble the sequential treatment schemes to be evaluated. The building of these
schemes must be done as part of the application of WAWTTAR by a user familiar with the
processes and their general capabilities.
WAWTTAR is intended for use on actual field water and wastewater treatment and reuse
problems. Extensive efforts have been made to provide accurate cost and performance data
which are applicable for a wide range of real world applications. The user should, however,
validate the reasonableness of all construction cost, operational cost and performance data for all
processes relative to the actual settings of the application.

Data Collection
The principal strength of WAWTTAR as a tool to support effective decision-making is its ability
to accept and consider a wide range of site-specific data in developing the sets of feasible and
infeasible solutions for wastewater collection and treatment. WAWTTAR presents numerous
tables in which the user is required to supply information. These tables serve not only as inputs
to the software, but also as guides for planners and decision-makers regarding the range and
quality of information which should be considered in the development of infrastructure
initiatives. A thorough consideration of all informational components will ensure that issues
ranging from material availability to the presence of spares and institutions to ensure
sustainability are incorporated into planning and pre-feasibility analysis.

Community Data
The principal set of data which the user must individually input are those which are site-specific
to the location being considered for infrastructure improvement. These data are intended to
describe the conditions under which the proposed project is to be implemented. These should be
collected collaboratively with local leaders, planners and engineers. These community data are
divided into several categories as displayed below:
1. General
� Community identification
� Community location
� Stakeholders

2. Demographic
� Population, density and growth rate
� Household size
� Spatial growth
� Current and projected water use
� Current and projected wastewater production
3. Resources
� Availability of construction, operation and maintenance equipment and
materials
� Energy and labor resources
� Availability of chemicals, media and laboratory services
4. Hydro-meteorological
� Precipitation and evaporations rates
� Surface temperatures and frost lines
� Raw water and wastewater quality
� Point source inputs
� Collection system description
5. Financial
� Planning horizons
� Exchange rates
� Interest, discount and inflation rates
� Construction and O&M cost indices
� Land values
6. On-site
� Soil and ground types
� Depth to water table
� Isolation distances from relevant features
� Dwelling types
� Defecation practices
� Gender issues
� Accessibility and waste hauling practices
This wide range of categories includes many which are frequently overlooked. The capacity of
responsible institutions, for example, has a major impact on what technologies are feasible to
use. A complex and highly technological treatment system may be a viable option in terms of
influent characteristics and treatment requirements, but such a system is likely to fail in remote
areas or where there is little in the way of government support or training opportunities.

The availability and cost of resources can dramatically affect the feasibility of treatment and
reuse options in every project stage from construction to operation and maintenance. Resources
in the case include the type and reliability of power supply, manpower from simple unskilled
labor to technical and professional personnel, treatment chemical availability, and any other type
of human or physical capital that might be necessary.
Additionally, social factors of the community in question are of high importance but are
infrequently recognized. Local attitudes and norms regarding defecation, waste handling, gender
relations, preferred dwellings and family structure can affect design criteria ranging from raw
wastewater quality to the types of technologies which are acceptable and likely to be used by
community members. Failure to adequately characterize and account for these factors in
planning and design can result in the selection of inappropriate technologies, and ultimately in
the failure of a treatment system regardless of how well designed from a physical and
technological standpoint.

Treatment Process Data
The second type of data utilized by WAWTTAR are Treatment Process Data. The main purpose
of the process data tables in WAWTTAR is to provide information on the capabilities, physical
and cultural limitations, costs, resource requirements and possible environmental impacts of
water and wastewater treatment and reuse processes. Such information for nearly 200 water and
wastewater treatment processes is provided in the WAWTTAR database. All of the data
associated with each process is available for review by the user as a reference to help with the
user's understanding of the applicability of each process. In addition, while the list includes a
wide range of processes, users can easily add new processes to take into account factors such as
local conditions and new technologies.
For each process, a set of tables contains information that defines the characteristics of the
process. The tables and their content are shown below:
1. General
� Type of process
� Identification of descriptive files for process
2. Construction
� Equipment, energy, labour and material requirements
� Construction costs relative to hydraulic, solids and organic loadings
� Economic life span of process
3. Operation and Maintenance
� Land requirements relative to hydraulic, solids and organic loadings
� Equipment, chemical, media, laboratory and material requirements

� Process control and energy needs
� Operation and Maintenance costs relative to hydraulic, solids and organic
loadings
� Solids production rate and moisture content
� Allowable influent quality values
� Removal efficiency for influent constituents
� Adaptability of process to upgrading, flow variations and influent quality
4. Siting
� Allowable precipitation and surface temperatures
� Required surface soil types and percolation rates
� Necessary horizontal and vertical isolation distances
5. Impacts
� Nutrient management
� Pathogenic organism production
� Pest breeding
� Odour generation
� Requirements for education
6. On-site Miscellaneous
� Institutional requirements
� Allowable population density and dwelling requirements
� Adaptability to social practices and living conditions
� Waste handling requirements
Each process is defined by up to three generic construction cost, O&M cost and land requirement
curves based on hydraulic loading, organic loading and solids loading. The majority of the cost
and land use data were taken from USEPA references. All costs were brought forward to a
common base year of 1992 based on an Engineering New Record (ENR) index. Costs are then
brought up to the first year of the proposed project by WAWTTAR based on the inflation rate
data provided in the community profile tables.
Most of the cost curves are average costs in the United States for a wide variety of geographical
and economic settings. These cost curves are then localized by WAWTTAR by adjusting based
on component cost factors for the community of interest using data provided in the community
profile tables. For construction costs, the relevant component cost categories are labor,
earthwork, manufactured equipment, structures, concrete, steel and appurtenances. For O&M
costs, the relevant categories are labour, chemicals, materials and energy.

Building Treatment Trains
As has been previously noted, it is a requirement that users of WAWTTAR have at the very least
an acquaintance with water and wastewater treatment processes. At best, the user should be
thoroughly familiar with conventional and non-conventional treatment processes. This
familiarity should include process performance ability, equipment description, operation and
maintenance requirements, human resource requirements, effective combinations of processes
and environmental requirements. This knowledge is first applied to WAWTTAR in the selection
of the sequence of processes which the user instructs WAWTTAR to consider.
This development of a series of processes to meet a particular standard, guideline and/or reuse
goal is referred to as "building treatment trains". The WAWTTAR program will not
automatically build treatment trains. The user must select processes and arrange them in a logical
order in terms of the flow of the water, wastewater and/or solids. There are no default treatment
trains in the database.
The development of a wide range of alternative treatment trains for consideration is at the heart
of the WAWTTAR program. The user is able to prepare large numbers of different treatment
trains by combining the various unit processes found in the WAWTTAR process database. The
number and types of alternatives to be considered is a decision the user must make early in his or
her planning process. The wider the variety and the greater the number of treatment train
alternatives proposed, the greater the probability that a sustainable, feasible solution will be
found.
The diagnostic ability of WAWTTAR identifies specific resources or conditions which do not
support a particular process within a treatment train. This allows the user to address the
weakness, if possible, and then re-examine the train for feasibility. This aspect of the program is
as valuable as the program's ability to identify those trains and processes that can feasibly be
supported in a particular community.

Obtaining Results
After WAWTTAR has completed the calculations resulting from the combination of site-specific
community information and the selected treatment trains, the program output is written into two
output files. These files are the Feasible Solution File and the Infeasible Solution File. A display
menu is used to view these files along with other output files.

Infeasible Solution File
A description of any treatment train that does not meet the criteria established by the user is sent
to the Infeasible Solution File. The design or performance criteria not met will be listed for each
process in the train responsible for making the train infeasible. Frequently, infeasible trains can
yield more insight into the design or process problem than feasible trains, so the user is
encouraged to examine, edit and recalculate the performance of infeasible trains. A viable train

may be found to be infeasible due to the inclusion of a process which is incompatible with, for
example, influent quality, and the train may be rendered feasible with a relatively minor
alteration. This is one of the key aspects of use of WAWTTAR which relies intensively upon the
level of expertise of the user.

Feasible Solution File
Detailed descriptions of feasible treatment trains are written to the Feasible Solution File.
Breakdowns of capital costs, O&M costs, land requirements and land costs per process are
provided in the output as are the total cost for the train, total per capita cost and total cost per
dwelling. Adaptability indices which rate the adaptability of each train to upgrading, varying
hydraulic loading and changes in influent quality are also reported. Solids production is detailed
on a process by process basis. Final effluent quality for any constituents designated for tracking
by the user is also reported.
The feasible treatment trains are ranked by the cost factor chosen by the user, and each feasible
train is described with construction, O&M and total costs listed after the individual treatment
train cost breakdowns. A list of the annualized costs, project costs, land requirements and social
and environmental impacts for the optimal train completes the description of each feasible train.

Conclusion
WAWTTAR was developed as a predictive model to assist planners at the pre-feasibility project
stage to select water and wastewater treatment systems appropriate to existing resources in
particular locations around the globe. The purpose of WAWTTAR is to make available to
decision-makers a user-friendly and widely accessible computer program and database with can
be applied to urban and peri-urban settings and which can be used to assess traditional and
alternative sanitation technologies and display tradeoffs by manipulating technical and socio-
economic data which serve as principal inputs.
The key points regarding the application and use of WAWTTAR are contained in the following
box:
WAWTTAR
Key Points to Remember
1. It is pre-feasibility software for selection of appropriate wastewater management
processes.
2. It requires a wastewater engineer to maximize its application.
3. It provides an additional resource for an engineer to rely upon.
4. It also serves as a thorough reference for non-engineers.

Acknowledgements
The development of WAWTTAR and the majority of the technical information in this paper
result directly from the work of Brad A. Finney, Ph.D. and Robert A. Gearheart, Ph.D. These
two individuals are Professors of Engineering in the Environmental Resources Engineering
Department of Humboldt State University, Arcata, California 95521.
The creation and testing of WAWTTAR was funded by the Environmental Health Project of the
United States Agency for International Development (USAID). Copies of WAWTTAR can be
obtained by contacting John M. Gavin, USAID Environmental Health Project, 1611 North Kent
Street, Suite 300, Arlington, Virginia 22209-2111 USA (telephone 703-247-8730; fax 703-243-
9004; email gavinjm@cdm.com).

Treatment of Organic Waste from Industrial Facilities:

Application of the Anaerobic Technology for the
Treatment of Domestic Wastewater in Jamaica
Julia Louise Brown
Scientific Officer, Integrated Wastewater, Management Project, Scientific Research Council,
Hope Gardens, PO Box 350, Kingston 6., Jamaica
Tel: (876) 927-1771 to 4 ext. 3102, Fax: (876) 977-2194, Email: icomppm@cwjamaica.com

ABSTRACT
The anaerobic technology is not foreign to Jamaica. This technology has been in use for over two
decades as the conventional 'biogas plants' using animal manure. These plants are focused on
generating energy for household purposes, however there have been advances in the technology.
There is now the bio-septic tank for the on-site treatment of domestic wastewater. There is also
the implementation of a demonstration anaerobic pond for the treatment of sugar wastewater. In
developing countries like Jamaica, there are many competing demands on limited financial
resources available for development. Sewage treatment, though important for public health,
generally gets a lower level of recognition than for example a safe and reliable water supply.
The anaerobic technology has over the years generated a lot of interest from many different
groups/institutions such as the government, the private sector, the farmers and the population at
large mainly due to its energy producing potential. The anaerobic technology was promoted in
Jamaica by the Government of Jamaica (GOJ) through the Scientific Research Council (SRC)
and by the Government of Germany through the German Agency for Technical Co-operation
(GTZ).
The anaerobic treatment of domestic sewage using the UASB process has previously been
investigated under tropical conditions in countries such as Colombia, Brazil and India. The
feasibility for such a process was explored in Jamaica since there are comparable climatic
conditions.
The feasibility of the anaerobic treatment for sewage treatment was investigated by the operation
of two 115 L UASB reactors in parallel. Reactor 1 was seeded with digested cow manure, while
reactor 2 was not seeded (self-inoculation). Reactor 1 was used to determine the treatment
efficiencies (BOD, COD and TSS) under the existing conditions of sludge activity, temperature,
pH and wastewater concentration. Reactor 2 was used to show the possibility for self-inoculation
to effect substantial removal efficiencies. Reactor 1 was subjected to stepwise reduction in HRT
(11.5, 9.5, 7.5 and 4.6 hours) while reactor 2 did not show any initial stability in terms of
removal efficiency and was operated at HRT of only 11.5 hours.

Reactor 1 was stabilised within 3-6 weeks of operation with COD, BOD and TSS removal of 70,
86 and 70 % respectively, resulting in an effluent quality of 60 � 150 mg COD/L and 12 � 30 mg
BOD/L. Reactor 2 was achieving some stability after 12 weeks of operation with COD removal
of 50 %, BOD of 65 % and TSS of 70 %.
Anaerobic treatment can become an attractive alternative for treatment in Jamaica. However, an
anaerobic treatment is a pre-treatment process, post-treatment is required for the removal of
pathogenic organisms, NH
3-
4-N,PO4 and the remaining suspended solids.
Keywords: Anaerobic technology, UASB process, domestic sewage, sewage treatment, post-
treatment.

1.0 Introduction
1.1 Background
The anaerobic technology is not new to Jamaica. This technology has been in use for over two
decades as the conventional biogas plants using animal manure. These plants are focused on
generating energy for household purposes. There have however been advances in the technology
to what is now called the bio-septic tank for the on-site treatment of domestic wastewater and
since recently there was the implementation of a demonstration anaerobic pond for the treatment
of sugar wastewater at one of the island's sugar factories.
The anaerobic technology has over the years generated a lot of interest from many different
groups/institutions such as the government, the private sector, the farmers and the population at
large mainly due to its energy producing potentials. The anaerobic technology is now been
promoted in Jamaica by the Government of Jamaica (GOJ) through the Scientific Research
Council (SRC) and the Government of Germany (GOG) through the German Agency for
Technical Co-operation (GTZ).
In developing countries like Jamaica, there are many competing demands on the limited financial
resources available for development. Sewage treatment, although important for the public health,
generally gets a lower level of recognition than for example a safe and reliable water supply
system. The national average generation of sewage in Jamaica is 450,000 m3/day, which is
equivalent to approximately 50,000 to 60,000 kg BOD/day. Sewage is the largest source of
pollution in Jamaica, although industrial water pollution takes a close second place (150,000
m3/day). The effects on water pollution are to be found everywhere in Jamaica. The present on-
site and most of the off-site systems of sewage disposal provide little treatment resulting in a
direct disposal of the polluting load into surrounding ground and surface waters. The need for
quick solutions has become a priority.
In view of the economical situation existing in Jamaica and the necessity for pollution control,
wastewater treatment technologies should be cost effective and environmentally sound. It should
combine a high treatment efficiency with plainness in construction and operation and the
possibility for some form of efficient removal of pollutants.

As stated by Louwe Kooijmans and van Velsen (1986), sewage treatment in developing
countries can be realized successfully only when the method of treatment has a bearing on the
local conditions. This implies:
� Construction of the plant has to be simple with as less moving parts as possible and
minimum of mechanization.
� The plant should be built with locally available materials.
� The investment costs have to be as low as possible with a low foreign currency
component.
� The operation and maintenance of the plant has to be as simple as possible.
� The energy requirement and the annual running costs have to be low.
� In cases where land availability is restricted, low land requirement is an advantage.
� The preferred biological process has to meet the desired effluent quality standards.
Although the presently available conventional aerobic wastewater treatment systems may have
very high removal efficiencies they suffer from severe drawbacks or disadvantages.
These are: -
� High operating cost for aeration
� High production of unstabilised sludge which has to be stabilised before disposal
� Lack of skilled manpower for operation
� High land requirement
There are also traditional pond systems, which are very effective in the treatment of domestic
wastewater, but have the limitations of being too expensive if no cheap land is available.
The application of the anaerobic technology for the treatment of domestic wastewater was
demonstrated under tropical conditions using the UASB process in Colombia (Lettinga, 1992;
Schellinkhout et al., 1985, 1988), India (Draaijer et al., 1992), Brazil (Viera, 1988; Viera and
Garcia, 1992) and Indonesia (Bogte et al., 1993; Lettinga et al., 1993) resulting in BOD removal
of over 75 %. Jamaica has an average temperature of around 30 oC and therefore provide a useful
ground for such a study.

1.2 Objectives
The objective of the study was to assess the feasibility of the anaerobic technology for the
treatment of domestic wastewater using the UASB system under Jamaican conditions in terms
of:
� The removal of pollutants (BOD, COD, TSS);
� Optimising the design criteria for further extension of the UASB treatment systems in
Jamaica by assessing the applicable hydraulic loading rate;
� Assessing the possibility for start-up without inoculum;
� Gaining hands-on experience in the operation and monitoring of anaerobic sewage
treatment plants.

2.0 MATERIAL AND METHOD
The study conducted was divided into three phases or aspects. These are:
� Experimental set-up (system description)
� Process start-up
� Operation and Monitoring

2.1 EXPERIMENTAL SET-UP
2.1.1 Set-up (System Description � The Pilot Plants)
The pilot plant reactor system was installed at the Independence City, Portmore, St Catherine
(Figure 2.1) and was fed with the sewage collected by the local aerobic treatment plant.
The pilot plant reactors have a total liquid volume of 115L (0.115 m3) and are constructed of
polypropylene (pp). They consist of a main pipe of 4.0 m tall (_ - 193 mm) to which an arm is
attached, which serves as the sedimentation chamber and serves for the settling out of the solids
and the collection and withdrawal of the effluent. It has a diameter of 153 mm, length of 953 mm
and a volume of 17.5 L. The upper part of the reactor serves as the gas collection unit (5L) and at
the joining of the sedimentation arm to the main pipe is the three-phase separator (gas-liquid-
solids). Sampling ports are located at every 50 cm along the length of the reactors as 1.27 cm pp-
ball valve connected to the main pipe with 1.27 cm pieces of pipes. The reactors are of the
UASB type with one feed inlet, which is equivalent to one inlet per 0.03 m2. The wastewater
enters at the bottom and leaves at the top.

The sewage first enters the grit chamber where the sand and the grit are removed. From there it
flows to a distribution tank where the wastewater is distributed to the aeration basin of the
existing plant under gravity. The wastewater from the distribution tank was pumped to an
equalization tank (225L plastic drum) from which the reactors were fed and the influent sampled.
The wastewater was pumped to the drum and the reactors on a continuous basis and was only
disturbed due to the occasional blockage of the hoses caused from the accumulated solids in the
grit chamber and the distribution tank. The wastewater in the drum had a residence time of about
4h. The drum was however emptied and cleaned on a daily basis to prevent the accumulation of
solids. It should be noted here that due to the accumulated solids in the grit chamber and the
distribution tank as well as the rapid growth of algae in the hoses, very high COD and solids
concentrations were sometimes occurring in the wastewater. This was dealt with by the thorough
cleaning of the hoses on a weekly basis to prevent the accumulation, which would also, result in
blockage and prevent the continuous operation of the system.

2.2 PROCESS START-UP
The two pilot plants (Reactor 1 and Reactor 2) were operated in parallel, reactor 1 (R) was
seeded with digested cow manure and reactor 2 (R2) was not seeded (self-inoculation). R1 was
used to determine the treatment efficiencies (BOD, COD, TSS) under the existing conditions of
sludge activity, temperature, pH and wastewater concentration. R2 was used to show the
possibility for self-inoculation to effect substantial removal efficiencies (BOD, COD, TSS).
For the non-seeded plant (R2) the following was done.
� The plant was filled with wastewater.
� The feeding was stopped for four week to assist in the development of the sludge bed
through processes of sludge accumulation and sludge improvement.
� The feeding of the system was then re-started to continue the development of the sludge
bed and to monitor the performance of the plant.
This process of feeding the system then allowing it to rest for a period of two weeks was based
on the experience made in Kanpur, India (Draaijer et al., 1992) for the start-up of a UASB plant
without inoculum.
R1 was loaded with 40 L of the digested cow manure (22.14 g TSS/L; 13.22 g VSS/L) as the
inoculum and then allowed to stand for a day to acclimatize to the existing conditions within the
plant, after which feeding was started. The sludge bed was then allowed to grow and become
acclimatized to the wastewater until steady state conditions were achieved.

2.3 SYSTEM MONITORING AND OPERATION
2.3.1 Influent � Effluent
Both the influent from the equalization tank and the effluent from the sedimentation chamber of
the pilot plant were sampled into a cooler initially using diaphragm pumps which pumps between
100-500mL/h. Due to the malfunctioning of some of the pumps (broken springs) the effluent was
allowed to flow under gravity to the sampling containers in the coolers. These composite
samples (24 hours collection time) were taken to the Waste Management Laboratory of the
Scientific Research Council for analysis.

2.3.2. Sludge Sampling
The sludge was sampled by taking a proportional sample, that is, along the entire length of the
reactor. This was done using a 1.27 cm PVC tube with a length of 4.5m containing a cord and a
stopper running through the entire length. The tube was inserted into the reactor by removing a
stopper from the gas chamber (see figure 2.3). When the tube was fully inserted and full of
sample, the cord was tightened and the tube was now closed and removed from the reactor and
the sample collected into a measuring cylinder.

2.3.3 Sampling and Analysis
The following analyses were performed for the monitoring of the pilot plant. The frequencies
were chosen to get a wide appreciation of the behaviour of the system over the entire
experimental period, as well as in response to the workload that could be handled for the study.
Table 3.1: Basic operating conditions of the reactor
systems (Mean +standard deviation and the Range)
Period
Temperature
Surface Load
HRT
pH
(Days)
(� C)
(m/h)
(hrs)H
28+ 2
7.4 + 0.5
2-43
0.35 11.5
(26�30)
(6.9�7.7)
27 +2
7.6 + 0.3
43�80
0.42 9.5
(25�29)
(6.8�8.3)
28 + 2
7.5 + 0.2
80�111
0.53 7.5
(26�29)
(7.3�7.7)
111�123 29
7.4
0.87
4.6
Parameters Frequency

Influent - Effluent
Temperature
Daily, momentaneous, on spot
pH
Daily, momentaneous, on spot
COD (total, settled, centrifuged)
Daily, momentaneous, on spot

BOD5
Weekly, 24 hrs composite sample
TSS, VSS
Weekly, 24 hrs composite sample
VFA, Alkalinity*
Weekly, 24 hrs composite sample
NH4-N, TKN
Weekly, 24 hrs composite sample
GAS

Production
Daily
Sludge Bed
Every six weeks
MLSS, MLVSS
Every six week
Methanogenic Activity
Every six week
Settleability
Every six week
Stability
Every six week
Sludge Mass
* During the first four weeks, it was done on daily basis.
For the analysis on the influent and effluent the standard method were followed with the
exception of the COD. The COD was analysed according to the Hach method (see below). The
gas production was measured using a wet gas meter. The settleability (initial settling velocity and
sludge volume Index) were determined using the Imhoff cone. Total suspended solids and
volatile solids were determined according to the standard method. The anaerobic activity and
sludge stability was measured in a batch experiment using molasses as substrate at 30 � C. The
volatile fatty acids and alkalinity were analysed titrimetrically.

COD
The COD was measured using a Hach System from Hach International situated in the United
States of America. It consist of Hach COD-reactor DR/2000 spectrophotometer and vials
containing COD reagents 0 � 15000mg/L, 0 � 1500mg/L and 0 � 150mg/L). This method was
tested by the analytical laboratory of the Scientific Research Council (SRC) and is comparable to
the standard method of measurement (+10 %).

3.0 RESULTS AND DISCUSSIONS
3.1 INTRODUCTION
Due to occasional periods of pump breakdowns, it was impossible to keep the plant in
continuous operation over the whole experimental period. The clogging of the filter (even though
cleaned daily) and the growth of algae in the hoses hampered the smooth operation of the plants.
This showed major impact on the irregular pattern of the gas production.

3.2 START-UP OF THE UASB REACTORS
The operation of R1 was started at a HRT of 11.5 hours during days 2 � 43, 9.5 hours during
days 43-80, 7.5 hours during days 80-111 and 4-6 hours during days 111-123. R2 was operated
at only HRT of 11.5 hours because the removal efficiency (BOD, COD and TSS) did not indicate
early stabilization to effect step-wise reduction in the HRT. The basic operating conditions of the
plants are shown in table 3.1

3.3 SYSTEM MONITORING AND OPERATION
The results presented were obtained during a five month period of operation (end October 97�
end March 98).

3.3.1 Influent - Effluent
3.3.1.1 Influent Characteristics
The sewage treated in the pilot plants was domestic in origin and originated from the
independence City sewage collector which receive the wastewater of seven communities of
approximately 130,500 inhabitants. According to the National Water Commission (NWC) the
water consumption is approximately 250 L/cap/day and approximately 80 % is discharged. The
wastewater is very septic in nature (COD / BOD ratio = 3.00 � 3.77), very high in suspended-
COD (157 mg TSS/L, 125 mg VSS/L) and was very dilute (COD- 429 mg/L (see table 3.2). This
was similar to the situation observed in Cali, Colombia (Lettinga, 1992). The most important
characteristics of the sewage are presented in table 3.2, which present the average values as
measured over the entire experimental period.

Table 3.2: The main characteristics of the Independence City sewage.
PARMETER
ENTIRE PERIOD

X
Stdev
Min
Max
CODtotal
(mg/L)
429
� 233
138
123
CODcentr.
(mg/L)
151
� 60
33
325
CODsettled
(mg/L)
194
� 76
58
408
BODtotal
(mg/L)
118
� 28
63
169
COD/BOD

365

TSS
(mg/L)
157
� 129
10
667
VSS
(mg/L)
125
� 112
5
607
TKN
(mg/L)
31.1
� 5
2.7
38.1
NH4-N
(mg/L)
20.5
� 3.1
14.9
24.4
Temp
(oC)
28
� 2
25
30
The averages and ranges calculated from selected sewage parameters for each HRT are shown in
table 3.3
Table 3.3: Main influent characteristics at the different HRT (mean Standard and Deviation
Ranges)
HR
CODtotal
CODcentr.
CODsettled BOD
TSS
(Hours) (mg/L)
(mg/L)
(mg/L)
(mg/L)
(mg/L)
336 � 190
135 � 61
172 � 70
110 � 30
115 � 88
11.5
(138�842)
(33�269)
(75 � 393)
(63-140)
(10-402)
407 � 167
166 � 62
218 � 81
108 � 10
119 � 90
9.5
(141-971)
(60-320)
(80-330)
(90-121)
(44-457)
554 � 28
152 � 57
189 � 78
168 � 0.7
239 � 158
7.5
(181-1233)
(58-339)
(56-246)
(168-169)
(45-667)
504 � 279
150 � 49
202 � 67
246 � 157
4.6
not determined
(188-785)
(100-206)
(133-304)
(77-406)

3.3.3.1 Performance of Reactor 1
As shown in figure 3.5, from the beginning of the experiment, the performance of the plant in
terms of COD � removal efficiency was fairly satisfactory (>50 %). The low removal efficiency
(ECOD total) during the initial period of operation (HRT = 11.5 h) can be attributed to the
absence of a sufficient quantity of proper bacterial sludge to carry out the digestion of the
organic material. However, the low regions of ECOD total at HRT of 9.5 hours is mainly due to
the sludge washout that occurred during that period (see figure 3.5). The treatment efficiencies
based on centrifuged effluent samples relative to total influent samples, ECOD Max, represent
the maximum possible efficiency of the system that can be achieved under the prevailing
conditions. This ranges from 75 � 86% for the different HRT. These results obtained are

comparable to the results obtained from studies under tropical conditions in Cali, Colombia (70 �
90 %) as shown by Lettinga (1992) and in Kanpur, India (>75 %) as shown by Draaijer et al.
(1992).
With the stepwise reduction of the HRT and the subsequent increase in the volume and the
activity of the sludge due to the growth of sufficient quantity of proper bacterial sludge, the
overall removal efficiency increased. This increase in COD � removal could also be attributed to
the fact that at the lower HRT there was an increase in the influent COD concentration. It was
observed that at higher influent COD values there was an increase in the removal efficiency
(ECOD total and ECOD Max). The occasional washout of sludge from the reactor and the
growth of algae in the effluent hoses affected the overall ECOD total. Nevertheless, an ECOD
total of 65 � 75 % was achieved.

BOD
The BOD was analysed on weekly composite samples and maintained a very high removal
efficiency of 82 � 90 % (see figure 3.6). The BOD values in the effluent range from 9 � 30 mg/L,
which is within the limits of the Jamaican standards of 30 mg/L.

TSS
Despite the high levels of solids in the influent, the removal of solids in the system was fairly
satisfactory. This ranges between 58 � 82 % for different HRT. The initial low TSS (HRT = 11.5
h) in the system can be explained by the small amount of sludge that was present in the reactor,
which reduces the likelihood of entrapping non-settleable solids in the system. However this was
improved with time due to the increase in the sludge mass, which increased the entrapment of the
non-settleable suspended solids. The occasional washout of sludge from the reactor and the
growth of algae in the effluent hoses affected the TSS removal efficiency like the ECOD total.

3.3.3.2 Performance of Reactor 2
R2 was operated at only one HRT (11.5 h) and was operated with the aim of `self inoculation' to
effect efficient removal (COD, BOD and TSS) as well as to observe the possible time period
required for start-up. The process of self-inoculation is of eminent practical importance, as
adequate seed materials for start-up is not available in developing countries like Jamaica.
As can be seen in figure 3.9 the COD removal efficiency (ECOD Max and ECOD total) follows
a very irregular pattern. During the first few months or period of operation not much happened
with respect to ECOD total. This could be due to the fact that the incoming wastewater was very
dilute and the reactor was therefore started at too high a HRT (11.5 h). This resulted in the
inability of solids present in the wastewater (TSS � 144 mg/L) to settle in the reactor and was
washed out in the effluent. This was confirmed in the ECOD Max (see figure 3.9) which was
fairly satisfactory from the beginning with a removal efficiency greater than 50 % signifying the

inability of the system to remove the soluble COD. As is evident from figure 3.9 with time the
possibility for `self inoculation' to effect substantial removal efficiencies in COD is feasible and
could possible be faster if reactor is initially operated at a lower HRT (e.g. 24 h).

BOD
The BOD removal in the system was fairly satisfactory and ranges between 60 � 70 % with
values in the effluent of 32-40 mg/L.

TSS
The TSS removal efficiency in R2 like the COD removal follows a very irregular pattern (see
figure 3.10). The inability of solids to accumulate in the system was evident in the TSS removal.
This can be explained by the lack of sludge in the reactor during the initial period of operation,
which prevented the likelihood of entrapping non-settleable solids in the reactor. There was an
overall removal efficiency of over 70 %. The initial (period 1) high removal of solids in the
system resulted when there was little solids present in the influent (see table 3.3).

3.3.4 Gas Production
The gas yield in R1 was an average of 0.13 Nm3 CH4 /Kg COD removed. For R2 the gas
collection was hampered by the problems encountered and thus was not included in the results.

3.3.5 Sludge Bed Characteristics (R1) and the effect of the reduction in HRT
The methanogenic activity of the sludge in R1 was determined every six weeks at the change of
each HRT. Specific activity measurements at 30 �C on the sludge made over the entire
experimental period reveal a gradual increase from 0.24 kg COD/kg VSS. day at HRT of 11.5 h
to 0.4 kg COD/kg VSS.day at HRT of 7.5 h to 0.54 kg COD/kg VSS. day. However at HRT of
9.5 h there was a decrease to 0.1 kg COD/kg VSS. day, which is unexplainable.
The sludge load obtained in the reactor was 0.05 � 0.3mg COD/mg VSS.d and was low in
comparison to that of activated sludge (0.5 � 1.0mg COD/mg VSS.d (see figure 3.11). This may
be due to the low methanogenic activity or due to a low supply of organic matter and was
confirmed by a plot of the maximum methanogenic activity and the value measured in the
reactor (SLR) again the HRT as is shown in figure 3.11.

From figure 3.11 there was no identity of the measured maximum specific activity
and that of the values measured in the reactor. All the maximum activity values
exceeded that of the values measured in the reactor at all HRT, indicating that
there was a substrate limitation within the reactor at all the HRT.
The settleability of the sludge as determined by the Sludge Volume Index (SVI) ranges from 15
� 30 mL/g for the different HRT indicating a good settleability for the sludge. This could be
explained by the increase in superficial velocity with a decrease in HRT (see table 3.1).
The amount of sludge in the reactor decrease with a decrease in HRT (see table 3.4), which was
due to the occasional sludge washout that, occurred in the system through sludge growth and
subsequent sludge bed expansion.
Table 3.4: The sludge composition and sludge mass in R1 at the different HRT
HRT
Sludge Mass
Sludge Composition
g TSS/L
11.5
22
0.60
9.5
24
0.66
7.5
17.5
0.58
4.6
16.3
0.68
The sludge stability was assessed from the methane production of the sludge samples at the
different HRT. The methane production was followed for a period of three weeks. The sludge
was stabilised with a production of 14-47mL CH4/g VSS.
The sludge age or solids retention time within the system was between 33-75 days.
The excess sludge production in the system was estimated on the basis of the TSS removal
efficiency and the volatile fraction of the influent suspended solids and the sludge present in the
reactor respectively. Together with the TSS content of raw sewage, the excess sludge production
can be estimated at approximately 63 kg TSS/1000 m3 wastewater (10.15 kg TSS/kg COD).

CONCLUSION
4.1 Summary of Results
A study was conducted using two reactors, one seeded (R1) and the other unseeded (R2) to
demonstrate the feasibility of the anaerobic treatment of domestic wastewater in Jamaica. A
summary of the results is shown in table 4.1.

Table 4.1: Conclusions of results of pilot plants experiment in Portmore, Jamaica
with domestic sewage.
1 For R1 start-up can be achieved at a HRT of approximately 5 hours within 3-6 weeks. While for R2,
which was unseeded, start-up can be achieved at HRT of 11.5 hours (it was operated at only this HRT) within
15-20 weeks. However, it is possible that start-up can be done at a higher HRT if the initial phases are operated
at a lower HRT (e.g. 24 hours) and then decreased.
2a. Treatment efficiencies R1 (HRT 11.5 � 4.6 hours)
COD (total/total)
55 � 72 % (64 %)
COD (total/centrifuged)
74 � 86 % (80 %)
BOD (total/total)
82 � 90 % (86 %)
TSS
58 � 82 % (70 %)
2b. Treatment efficiencies R2 (HRT 11.5 hours)
COD (total/total)
30 � 70 % (50 %)
COD (total/centrifuged)
52 � 72 % (62 %)
BOD (total/total)
60 � 70 % (65 %)
TSS
60 � 80 % (70 %)
3. Gas production
R1 0.13 Nm3 CH4/kg COD removed
4. TSS-conversion (R1)
Appr. 27 % of the TSS leaves the reactor in the effluent
Appr. 42 % of the TSS is found in the sludge
Appr. 25 % of the TSS is converted to gas
5. Sludge retention of the reactor and sludge age
Sludge retention (R1)
16.5 � 23.5 kg TSS/m3
10.3 � 15.4 kg VSS/m3

Sludge retention (R2)
1.9 kg TSS/m3
1.8 kg VSS/m3

Sludge age (R1)
33 � 75 days
6. Sludge bed characteristics (R1)
Ash content
35 � 45 %
Spec. Meth. Act.
0.1 � 0.54 kg COD/kg VSS.day
Stability
14 � 47 mL CH4/g VSS

4.2 Overall Conclusions
1. Anaerobic treatment can become an attractive alternative for Jamaica because:
� Under Jamaica's tropical conditions dilute sewage can be digested
efficiently under both seeded and unseeded conditions as shown on pilot
scale
� In Jamaica where there is a general problem existing with high rate
treatment system due mainly to financial reasons, anaerobic process
indicates an economic advantage.
� Significant low sludge production rate reduces the cost for sludge
treatment/disposal. The sludge is also well stabilised.
2. In view of the satisfactory performance of the seeded system (R1), particularly in terms
of its positive response to the imposed higher hydraulic loading rates, it can be concluded
that the system is suited to accommodate a higher rate of start-up.
3. The unseeded plant (R2) initial phase of operation should be done at a lower HRT (24
hours) to allow some form of sludge built to take place so that start-up can be achieved at
a higher rate and in a shorter period of time.
4. As anaerobic treatment is a pre-treatment process, post treatment is required for the
removal of pathogenic organisms, NH4-N,PO43- and the remaining suspended solids.

5.0 RECOMMENDATIONS
5.1 Reactor 1
The study was conducted over a period of only five months, which was insufficient to thoroughly
explore all the parameters or areas necessary to optimise the process for further design purposes.
Therefore the plant should continue to be operated with better control of the influent (in terms of
solids) with reduction in the HRT in an attempt to establish maximum point of operation for the
system for design purposes.
5.2 Reactor 2
The plant should continue to be operated for at least another six months in order to establish
stability in terms of COD and BOD removal and for it to be subjected to stepwise reduction in
HRT so that the maximum potential of the system can be established. This would provide for
more concrete conclusions to be made of the possibility for self-inoculation for the treatment of
domestic wastewater in Jamaica.

6.0 REFERENCES
Draaaijer, H., Maas, J.A.W., Schaapman, J.E. & Khan, A. (1992). Performance of the 5 MLD
USASB reactor for sewage treatment at Kanpur, India. Water Science and Technology, 25(7):
123 � 133.
Bogte, J.J., Brere, A.M., van Andel, J.G., & Lettinga, G. (1993). Anaerobic treatment of
domestic wastewater in small scale UASB reactors. Water Science and Technology, 27 (9): 75 �
82.
Lettinga, G., de Man, van der Last, A.R.M., Wiegant, W., van Knippenberg, K., Frijns, J. & van
Buuren, J.C.L. (1993). Anaerobic treatment of domestic sewage and wastewater. Water Science
and Technology, 27 (9): 67 � 73.
Louwe Kooijmans, J. & van Velsen, E.M. (1986). Application of the UASB process for the
treatment of domestic sewage under sub-tropical conditions, the Cali case. Anaerobic Treatment.
A grown-up technology. Conference papers (Aquatech 1986), p423 � 436.
Schellinkhout, A., Jakma, F.F.G.M. & Forero, G.E. (1988). Sewage treatment: the anaerobic way
is advancing in Colombia. Fifth International symposium on Anaerobic Digestion (Poster-papers.
Tilche A and Rozzi A, Eds. Bolgna, Italy p767 �770.
Schellinkhout, A., Lettinga, G., van Velsen, L., Louwe Kooijmans, J. (1985). The application of
the UASB-reactor for the direct treatment of domestic wastewater under tropical conditions.
Proceedings of the Seminar/Workshop on Anaerobic Treatment of Sewage. Switzenbaum Ed.
Amherst, USA, pp. 259 � 276.
Lettinga, G. (1992). Treatment of raw sewage under tropical conditions. Malina, J.F. and
Pohland, F.G. Design of Anaerobic Processes for the treatment of Industrial and Municipal
Wastes. Water Quality Management Libraries. Vol.7, USA. P 147 � 166.
Viera, S.M.M. (1988). Anaerobic treatment of domestic sewage in Brazil � Research results and
full-scale experience. Proceedings of the 5th International Symposium on Anaerobic Digestion.
Bologna, Italy. Hall ER, and Hobson PN, Eds. P185 � 196.
Viera, S.M.M. & Garcia Jr., A.D. (1992) Sewage treatment by UASB reactor. Operation results
and recommendations for design and utilisation. Water Science and Technology, 18 (12): 109 �
121.

7.0 Acknowledgement
The author would like to acknowledge the members of the Integrated Waste Management project
especially two hard working Scientific Officers (Mr. Desmond Samuels and Mr. Delroy Peters)
who contributed wholehearted to the overall running of the project and the acquisition of the
data.

GLOSSARY
Aerobic
Presence of dissolved oxygen
Anaerobic
Absence of dissolved oxygen
BOD
Biochemical oxygen demand, the amount of oxygen needed to

biologically degrade the organic matter present in the wastewater
COD
Chemical oxygen demand
ECODMax
Maximum removal efficiency based on the total
ECODtotal
Total removal efficiency based on total influent COD and the total
GOG
effluent COD.
GOJ
Government of Germany
GTZ
Government of Jamaica
HRT
Germany Agency for Technical Co-operation

Hydraulic Retention Time, the time in which the wastewater is maintained
MLSS
within the system, measured by the volume of the system over the flow.
MLVSS
Mixed Liquor Suspended Solids
NH4-N
Mixed Liquor Volatile Suspended Solids
Nm3 CH4
Ammonium-Nitrogen, the usable form of nitrogen for the bacteria
NWC
Amount of methane produced under standard conditions of temperature

and pressure
R1
National Water Commission, the water governing body in Jamaica which
R2
is responsible for >20 of the sewage generated
SRC
Reactor 1, the pilot plant reactor that was seeded with sludge
SVI
Reactor 2, the pilot plant reactor that was not seeded with sludge

Scientific Research Council
TKN
Sludge Volume Index (mL/g), the volume occupied by 1g of sludge after
TSS
settling of mixed liquor for 30 minutes
UASB
Total Kjeldahl Nitrogen, NH4-N + 0-N2

Total Suspended Solids
VSS
Upflow anaerobic Slidge Blanke/Bed, the most common type of
anaerobic reactor for wastewater treatment
Volatile Suspended Solids

Low Cost and Low Technology Alternatives for
Wastewater Treatment
John A. McKee, M.Sc., CGWP, P.Eng.
Oliver, Mangione McCalla, 154 Colonmade Road South, Nepean, Ontario, Canada K2E 7J5
Tel: (613) 225-9940 ext. 241, Fax: (613) 225-7337, Email: omm@trow.com

Introduction
The objective of wastewater treatment is to remove, convert and/or reduce the toxic and
pathological components of wastewater such as to effectively reduce the risk to human health
and ecological impact associated with effluent release to the environment. The level of treatment
required in a specific application is dependent upon the hydraulic and organic load of the
wastewater source and the required quality of the effluent. The quality of effluent which can be
tolerated varies from one application to another and is dependent upon the environment into
which the effluent is released.
A wide variety of treatment technologies and methods of implementation have been developed to
meet the various treatment requirements and constraints. These range in complexity from the
simple pit privy or septic tank/leaching field system for small domestic applications to the
technically more sophisticated packaged systems such as the Rotating Biological Contactor
(RBC), Sequencing Batch Reactor (SBR) or Extended Aeration Plants (EA) designed for higher
flows, wastewater strengths or more demanding discharge requirements. Each of these systems
has a specific application or niche within the wastewater treatment field.
The focus of this presentation will be low cost/low technology methods for wastewater
treatment. The focus will be on systems suitable for daily flows in the 5 to 50 m3/day (and larger)
range. A variety of applications will be considered including multiple family domestic,
institutional (ie. schools), commercial (ie. retail, restaurant) and industrial.
By comparison with the technically sophisticated systems discussed above, low technology
systems are simple in concept, design and operation. In most cases, the only operating
component is a simple effluent pump. If required energy requirements can be met from solar
power cell/battery combinations. In certain circumstances, systems can be setup to run entirely
on gravity. Once established, ongoing operational and maintenance requirements are minimal.
There is no requirement for ongoing balancing or chemical adjustment. High level training of
operators is not required.

System Descriptions
A brief presentation of three low cost /low technology systems used in North America will be
provided. These three systems are described as follows:

o Peat filter;
o Recirculating sand filter;
o Waterloo Biofilter.
The experience of the author is primarily with the peat filter systems which are discussed in
detail. The latter two are presented because they meet the low cost/low technology criteria while
providing a high level of effluent treatment. Data published by Ball (1995), Bruen and Piluk
(1994), Roy and Dube (1994) will be used to describe the recirculating sand filter.
Various papers published by Dr. Craig Jowet (1994, 1995) can be used to describe the Waterloo
Biofilter system.
A brief description of the conceptual design and operation of each system will be presented
together with a description of the treatment mechanism. The degree of treatment provided in
various applications as experienced by the author and/or reported in the literature will be
provided. There is an inherent variability in wastewater strengths associated with the various
sources. Parameters considered in this discussion will include Biochemical Oxygen Demand
(BOD), total phosphorous (as P), Total Nitrogen (total kjeldahl+nitrite+nitrate as N), and the
bacteriological parameters total and fecal coliform.

Peat Filter Systems
Peat filter systems for the treatment of domestic wastewater were originally developed at the
University of Maine by Dr. J.L. Brooks et al (1984). Working together with Dr. Brooks, the firm
Oliver, Mangione, McCalla successfully adapted and implemented the technology to serve a
variety of uses including single and multiple family residential, elementary and high schools,
commercial retail and restaurants. A detailed evaluation of the performance of these systems was
undertaken for the Ministry of the Environment for the Province of Ontario (OMM 1997), the
results of which will be summarized herein. In addition to the above, the literature provides
references to the use of peat for the treatment of industrial effluent containing heavy metals and
landfill leachate.
The design and operating principals of peat filters have been discussed in previous publications
including Brooks et al (1984), McKee and Brooks (1994) and McKee and Connolly (1995). A
schematic sketch of a typical peat filter treatment system is provided in figure 1. Primary
treatment of the wastewater is provided by a conventional two chamber septic tank. The effluent
then flows by gravity or alternatively is pumped to the peat filter system. The effluent is
distributed over the area of the peat filter through a network of perforated distribution pipes.
Dependent upon the setting, distribution can alternatively be accomplished through pressure
distribution or drip irrigation systems.
Treatment is provided as the effluent percolates vertically downwards through the peat to the
base of the system. The peat material acts as a host medium for micro-organisms which
accomplish the effluent treatment in an aerobic environment. The literature reports the use of
various types of peat from different sources with differing degrees of success. The peat used in

the systems described herein is a sphagnum type peat with a Von Post decomposition rating of
H-4, a pH of 3.5 to 4.5 and moisture content of 50 to 60 percent. This material is packaged and
can be easily shipped in bulk.
Effluent from the base of the peat can be handled in a variety of ways. For the systems
constructed in Ontario, the effluent percolates through the base to the groundwater table.
Depending upon the setting and regulatory requirements, systems can also be constructed with
under drain systems for discharge to remote leach fields, trenches or surface water.
A summary of the peat filter systems for which monitoring programs have been undertaken is
provided in table 1. The systems serve a variety of uses with varying waste water strengths.
Design flows range from 2 to 36 m3/day and organic loading of 34 to in excess of 500mg/L
BOD.
A detailed monitoring program of the above systems was completed and summarized by OMM
(1997). The program involved the collection of samples from the septic tank and base of the peat
filter at monthly or quarterly intervals for periods of from two to three years each. The results of
analysis are summarized below.

Years
Design
BOD
Phosphorous
Nitrogen
Flow
mg/L
mg/L-P
Mg/L-N
m3/day
Operate

range
avg
range
avg
range
avg
Schools
Elementary
8
15
48 - 143
92
2 - 9
6.1
40 - 80
65
6
10
28-341
132
1 - 10
4.8
52 - 101
82

5
10
0-76
34
3 - 8
6
45 - 74
57
4
20
17-96
55
0 - 10
5
35 - 75
63
5
9
15-176
73
1 - 14
7.8
63 - 165
109
Secondary
5
36
90-563
185
2 - 16
7.7
44 - 150
92
Domestic
Single Fam
5
2

331
23 - 48
34
129 - 198
157
Multiple Fam
5
9

142

8.7
49 - 80
52
5
7
110-195
141
2 - 12
6.8
8 - 30
40
Restaurant

5
18
285-717
502
8 - 24
15
67 - 183
100
Shopping
5
25
44-84
59
1 - 7
4
18 - 40
27
Center

5
25
125-676
401
1 - 21
8.3
30 - 130
64
Table 1: Summary of Peat Filter Systems and Influent Wastewater Characteristics
Available data indicates peat filters provide very high levels of treatment for the bacteriological
indicator parameters, total and fecal coliform. Reductions effectively exceed 99 percent. Total
and fecal coliform counts in almost all cases met the criteria for swimming water quality (total

1,000 per 100 ml, fecal 100 per 100ml) and in many cases exceeded the drinking water criteria
for total coliform of 5 per 100ml.

Figure 2: BOD Treatment - Peat Filters
Treatment of the organic component of wastewater is measured by the reduction in Biochemical
Oxygen Demand (BOD). The results for the twelve systems are summarized in figure 1 above.
Influent sewage strength varied with the nature of the source from relatively weak at less than
100 mg/l, to strong with average strengths in excess of 500mg/L.
In all cases, the peat filters provided excellent treatment for the removal of BOD. Average
reductions exceeded 90 percent. With the exception of the very high strength sources, the
effluent BOD concentrations were less than 10mg/L. BOD source strength is an important design
consideration. At loading rates of less than 5,000 mg/m2/day, effluent concentrations were
generally less than 10mg/L. At loading rates in excess of this amount, an organic clogging mat
can develop. Pretreatment should be considered for higher strength wastewaters.

Figure 3: Phosphorous Treatment - Peat Filter

The removal of phosphorous by peat filters is very good, with most systems exceeding a ninety
percent removal rate. Effluent phosphorous concentrations were generally less than 0.8mg/L-P in
most systems. Higher source strengths generally produced higher effluent strengths. The high
strength restaurant wastewater, with an influent phosphorous co centration of 15mg/L-P had a
n
n
effluent concentration of 2.8mg/L-P.
The phosphorous treatment provided by the systems studied by OMM (1997) is higher than that
reported by other authors (Brooks et al 1984). This is attributed to the perceived difference in
treatment mechanisms. The process for treatment of organic compounds, nitrogen and
bacteriological parameters is believed to be facilitated by biodegradation/bioaccumulation
undertaken by micro-organisms. Phosphorous reduction is considered to occur by adsorption.

Figure 4: Nitrogen Treatment - Peat
Filter

The assessment of nitrogen treatment involved the collection and analysis of influent and
effluent samples for Total Kjeldahl Nitrogen, Ammonia, Nitrite and Nitrate (measured as N).
The sum of all nitrogen species was considered at each stage in the treatment process as
summarized in figure 4 above.
Treatment within the peat filter occurs under aerobic conditions (Brooks et al 1984). Influent
nitrogen was measured primarily in the form of ammonia and organic nitrogen. Essentially
complete nitrification occurred within the peat filter with effluent nitrogen measured primarily in
the form of nitrate. The overall reduction in nitrogen species is dependent upon nitrogen loading.
Average reductions varied from 35 to 70 %. A fifty percent reduction in total nitrogen species
was obtained in systems with a total nitrogen loading of 1.4 grams/m2/day. Design of the peat
filter should consider both the influent wastewater strength and requirements for the point of
discharge.

The author has had experience with the design construction and operation of a total of fifteen
peat filter systems. Costs for construction of the complete system have generally ranged from 7
to 12 $CAN per litre for the complete system. Costs are comparable or only slightly higher than
conventional septic or sand filter systems. Costs are lower than the more sophisticated packaged
systems described at the beginning of the paper by a factor of 2 to 3 or more. The real advantage
of the peat filter system is the low operational and maintenance requirements. Operating cost is
restricted to the effluent pump which typically runs no more than 60 to 90 minutes per day. Once
established, the systems operate with minimal supervision. Maintenance is generally restricted to
the periodic cleaning of the septic tank.

Recirculating Sand Filters
Sand filters and more recently, recirculating sand filters (RSF) are in common use in unsewered
areas of the USA and are now being implemented in various areas of Canada. Figure 5 provides
a schematic layout of a typical recirculating sand filter. Septic tank effluent flows by gravity to
the recirculation tank where it is pumped to the sand filter. Treatment in the sand filter occurs
under aerobic conditions providing effective treatment for the removal of organic material
(BOD) and micro biological contaminants. Sand filters are effective for the nitrification of
ammonia and organic nitrogen to nitrate. Recirculating sand filters were developed to provide for
improved treatment for nitrogen. Nitrified sand filter effluent is redirected and mixed with the
raw wastewater where, denitrification occurs under the anaerobic conditions of the septic tank. It
is reported that trickling filters have been added to the septic tanks to further increase nitrogen
removal efficiencies (Ball 1995).

Figure 5: Schematic Layout - Recirculating Sand Filter

The sand filter consists of a minimum 0.6 metres of sand or gravel. Varying gradations of sand
have been reported. Piluk and Peters (1994) report an effective grain size of 1 mm and
uniformity coefficient of < 2.5. Ball (1995) reports a sand of effective grain size 2 mm to be the
most effective for nitrogen removal. The reported rate of loading to the sand filter is variable,
ranging from a low of 2 cm/day (Roy and Dube 1994) to as much as 55 cm/day (Piluk and Peters
1994).

The reported treatment efficiencies provided by RSF systems is very good. With respect to
bacteriological components, reductions of two orders of magnitude in fecal coliform were
reported by Bruen and Piluk (1994). Removal effectiveness is in part related to the thickness of
the sand filter. Dependent upon the setting and regulatory requirement, disinfection of effluent
would be required prior to discharge to the surface water environment. The removal of organic
contaminants as reflected by BOD concentrations is good with RSF systems. Removal
efficiencies in excess of 90 % were reported by Piluk and Peters (1994), Roy and Dube (1994).
In recent years, attention has been focused on the design enhancement of RSF systems to provide
optimum nitrogen removal. Nitrogen removal rates of 30 to 50% have been consistently
demonstrated in a variety of climates (Ball 1995). Bruen and Piluk (1994) report 66% nitrogen
reductions. The focus now is to increase this reduction by the addition of trickling filter systems
on the recirculation side of the septic tank/pump chamber (Ball 1995).
The cost for construction of RSF systems was reported by Bruen and Piluk (1994) for domestic
applications. An approximate cost of $5,850 US was reported for a home of two adults, four
children. Using an estimated 2,000 L/day flow, the equivalent system cost is therefore on the
order of $3 US/Litre. Similar to the peat systems. RSF systems require little to no maintenance
once commissioned. Op
ting cos
era
ts are limited to the energy required to operate the effluent
pump and periodic maintenance of the septic tank.

Waterloo Biofilter
The Waterloo BiofilterTM (WBF) is a proprietary system developed by Dr. Craig Jowett (1994,
1995) of the University of Waterloo, Canada and marketed by Waterloo Biofilter Systems Inc. of
Guelph Ontario. Jowet (1995) reports the use of these systems to treat a variety of wastewater
applications ranging from single family residential and m nicipa
u
l wastewater to landfill leachate.
Similar to the Peat and RSF systems, wastewater is treated in the WBF system as it passes
through the media, in this case an absorbent plastic media or foam with a high pore to solid ratio.
Wastewater is sprayed or sprinkled onto the surface of the biofilter media where it is absorbed.
As with the peat and RSF systems, treatment is accomplished under aerobic conditions by micro-
organisms hosted within the medium. Treated effluent is directed to the subsurface via leaching
beds or shallow disposal trenches or depending upon the regulatory setting directed to surface
water environment.
Treatment in the WBF systems if very good. Jowet (1995) reports removal rates for fecal
coliform of 99%. As with the RSF system, disinfection of wastewater prior to surface water
discharge would be required. The removal and treatment for organic contaminants as reflected by
the BOD is good. Reductions on the order of 90 % or better were reported for a number of single
family domestic and a municipal application. The WBF system consistently reduced the BOD of
a landfill leachate by 79%.
Treatment for nitrogen compounds is similar for the peat, RSF and WBF systems. Nitrification
of the effluent occurs under aerobic conditions within the filter medium. Ammonia removal in

the wastewater is reported by Jowett (1995) to be 80 to 90 percent. Total nitrogen removal for
these systems is reported in the range of 29 to 37%. Modifications to the system have increased
the nitrogen removal efficiency to 65%. The modifications involve the addition of a
denitrification module, consisting of a tank of sawdust which receives the WBF effluent prior to
discharge. Denitrification occurs within this system under anaerobic conditions with the sawdust
providing a source of carbon for the denitrifying bacteria.
Direct information on costs for construction of the WBF system can be obtained from the
manufacturer. As with the peat and RSF systems, operating costs are minimal associated with the
cost for operating effluent pump and blower systems and periodic maintenance and pumping of
the septic tank.

Summary and Conclusions
A wide variety of technologies have been developed to treat wastewater. Each of these
technologies has a specific niche within the market with applicability dependent upon such
considerations as wastewater volume and delivery patterns, wastewater strength and required
effluent quality. The required quality of effluent will depend upon the sensitivity of the
environment into which the effluent is discharged and applicable regulatory requirements.
The focus of this presentation has been low cost/low technology alternatives for wastewater
treatment. Three systems have been discussed: Peat filters, Recirculating Sand Filters (RSF) and
the Waterloo Biofilter (WBF). The three systems provide very high levels of treatment for the
organic compounds as measured by BOD and nitrification of ammonia and organic nitrogen. All
systems provide excellent treatment for bacteria with removal efficiencies exceeding 99%. Peat
filter effluent consistently meets swimming water criteria for fecal coliform. Depending upon the
ection of RSF and W
setting, disinf
BF effluent could still be required.
Treatment for nutrients in the form of nitrogen and phosphorous varies with the systems. The
peat filters provide good treatment with effluent concentrations less than 1 mg/L in most
applications. Phosphorous removal modules are being developed and are available for the RSF
and WBF systems.
Nitrogen removal efficiencies of 40 to 70% can be achieved with the peat filter. Similar rates
have also been reported with the RSF system. The use of a denitrification module in conjunction
with the WBF system brings nitrogen removal efficiencies into the same range as the other two
systems.
The initial capital costs for these systems are generally low, ranging from $5 to $15 CAN/Litre.
Operating costs for these systems is low, consisting primarily of the energy cost associated with
operating a small effluent pump. With the exception of the periodic cleaning of the septic tank
which provides primary treatment for the three systems, maintenance requirements for these
systems is low with little involvement required once the system is in operation and properly
balanced.

References
Ball, H.L., 1995. Nitrogen Reductions in an On Site Trickling Filter/Upflow Filter System. 8th
Northwest On-Site Wastewater Treatment Short Course and Equipment Exhibition, University of
Washington.
Brooks, J.L., Rock, C.A., and Struchtemeyr, R.A., 1984. The Use of Peat for On-Site Waste
Water Treatment: 2 Field Studies. Journal of Environmental Quality, Volume 13, No. 4, Pg. 524.
Bruen, M.G. and Piluk, 1994. Performance and Costs of On-Site
s.
Recirculating Sand Filter In
Proceedings, 7th International Symposium on Individual and Small Community Wastewater
Systems, ASAE, Atlanta.
Jowett, E.C
ter,
. and McMas
M.L. Absorbent Aerobic Biofiltration for On-Site Wastewater
Treatment - Laboratory and Winter Field Results. In Proceedings, 7th International Symposium
on Individual and Small Community Wastewater Systems, ASAE, Atlanta.
Jowett, E.C. 1995. Field Performance of the Waterloo Biofilter with Different Wastewaters. 8th
Northwest On-Site Wastewater Treatment Short Course and Equipment Exhibition, University of
Washington.
McKee, J.A. and Connolly, M. 1995. An Update on the Use of Peat Filters for On-Site
Wastewater Treatment. 8th Northwest On-Site Wastewater Treatment Short Course and
Equipment Exhibition, University of Washington.
McKee, J.A. and Brooks, J.L., 1994. Experience with Peat Filters for On-Site Wastewater
Treatment in Ontario. Conference on Wastewater Nutrient Removal Technologies and On-Site
Management Districts. Waterloo Centre for Groundwater Research, University of Waterloo,
Canada.
Oliver, Mangione, McCalla & Associates, 1997. Summary Report, On-Site Wastewater
Treatment, Thirteen Peat Filter Systems. Prepared for Ontario Ministry of the Environment.
Piluk, R.J. and Peters, E.C., 1994. Small Recirculating Sand Filters for Individual Homes. In
Proceedings, 7th International Symposium on Individual and Small Community Wastewater
Systems, ASAE, Atlanta.
Roy, C. and Dube, J.P. 1994. A Recirculating Gravel Filter for Cold Climates. In Proceedings,
7th International Symposium on Individual and Small Community Wastewater Systems, ASAE,
Atlanta.

The National Small Flows Clearinghouse and Lessons
Learned from the National Onsite Demonstration Project
David A. Pask
National Small Flows Clearing House, PO Box 6064, West Virginia State University,
Morgantown WV 26506-6064, USA
Tel: (304) 293 4191 ext. 5516, Fax: (304) 293 3161, Email: dpask@wvu.edu

Abstract
This paper describes the National Small Flows Clearinghouse as a resource for individuals and
small communities of the Caribbean seeking information and support for problems of sewage
treatment and disposal or pollution control. The National Onsite Demonstration Project is also
described with a discussion on some of the results of the monitoring program. The importance of
management of small systems is discussed together with the rationale for selection of an
appropriate system for a given circumstance. A method for the estimation of the hydraulic
capacity of a site is given with a description of techniques for measuring necessary parameters.

The Environmental Services and Training Division (ESTD) of West Virginia
University
The National Small Flows Clearinghouse (NSFC) and its sister organizations, the National
Drinking Water Clearinghouse (NDWC) and the National Environmental Training Center for
Small Communities (NETCSC) are national non-profit information services provided by the
University of West Virginia and are located on campus in Morgantown, West Virginia. The U.S.
Environmental Protection Agency (EPA) funds NSFC and NETCSC, while the U.S. Department
of Agriculture funds NDWC. All three organizations were founded to assist small communities
affected by the need to comply with ever more strict environmental legislation.
The clearinghouses are staffed by engineers, technical and administrative assistants, writers and
editors totaling approximately 65 persons. A number of national experts in various fields are also
available for referral when the need arises. During business hours trained staff are available to
receive telephone calls for advice on almost any subject related to water, wastewater and
environmental training. Queries may be received by telephone (toll-free within U.S.A.), by Fax
or regular mail. Most calls can be dealt with immediately, but referrals, and items requiring some
research may take a little longer. The Clearinghouses each produce two quarterly newsletters
relating to technical and administrative matters. Internet Web sites are maintained and include
electronic versions of the publications. Access will shortly be available to the very extensive
databases of technical and administrative abstracts. A very important service is the operation of a
product distribution service covering books, manuals, pamphlets and videotapes published by the
Clearinghouses, EPA and other government and independent organizations. Some items are free
with a small charge for shipping and handling, other items may include the cost of copying and
binding.

The Clearinghouses send representatives to many of the national and state conferences and
workshops, usually operating a staffed display in the exhibit area. Members of staff are
frequently asked to speak at these and other conferences.
The clearinghouses may be contacted �
by mail:
The National Small Flows Clearinghouse
(or NDWC or NETCSC)
West Virginia University
P.O. Box 6064
Morgantown, WV 26506 � 6064

by phone:
1 800 624 8301 (within US)
1 304 293 3161
by Fax:
1 304 293 3161
by Internet:
http://www.estd.wvu.edu

National On-site Demonstration Project, Phase 1
This project is drawing to a close. Six communities in five states participated in a program
intended to demonstrate proven alternative on-site technologies in sensitive areas where lack of
way to knowledge and/or regulation inhibited current acceptance. These technologies ranged
from modified standard septic tank/soil absorption through various forms of secondary treatment
for nutrient reduction to wetlands and drip irrigation. Monitoring was a requirement and included
some sophisticated sampling by lysimeter.
Results in general showed that the innovative technologies are indeed an improvement over
existing systems in protecting public health, groundwater and the environment but also showed
that more sophisticated treatment leads to the need for more sophisticated maintenance and
management. This can no longer be left to the average homeowner and his untrained pumper!

National On-site Demonstration Project, Phase 2
The experiences of Phase 1, have steered the advisory committee towards asking for an emphasis
on projects that will emphasize management aspects. All five participants will include
management and maintenance in the objectives of their demonstration. One participant will
concentrate all the effort into all the preparatory surveys and organization required to put in place
on on-site wastewater management district. Others will also include some innovative systems not
already in use in the area.

The NSFC National Survey of On-site Systems in the United States
This recently completed survey is a first attempt at assessing the status of the industry and of the
problems we will be facing in the immediate future. Tailored for maximum response, a
remarkable 45% return was produced from 3,500 questionnaires. The report has now been
published and is available from the Clearinghouse. A paper was presented at the ASAE meeting
in Orlando by Tricia Angoli in March of this year.
No specific questions were asked about management issues but a general trend can be inferred
from "Other Comments" added by respondents. Two papers at the above conference specifically
addressed the need for management; several other speakers mentioned the need when describing
alternate systems. I met no-one at many informal meetings at this and other conferences and
workshops that did not acknowledge that some form of management of maintenance will be
required for all systems throughout the country, especially for systems using advanced treatment.

Misconceptions as to the Use of Advanced Treatment Systems
While advanced treatment systems do have their uses, there are examples where the public,
installers and some professionals are advocating advanced treatment as the universal panacea for
all the ailments of on-site systems. I must add a few words of caution. Many malfunctions of
onsite systems are related to inadequate hydraulic conductivity of the subsoil. Advanced
treatment has no effect upon the hydraulic capacity of a building lot, Darcy's Law still
applies!
Advanced treatment should not be used unless there is a specific reason for its requirement. A
Decision Diagram may best illustrate this point. The following example is almost universal in
application.

Issues in Establishing Wastewater Management
The following is a partial list of the many issues that may need to be resolved in setting up a
Wastewater Management District or similar entity. Many of the decisions are both political and
social, but must be addressed.
A WHY MANAGE?
1) Protect health and environment for all.

Does this need explanation?

2) Minimize "Failure" (malfunction).

Failure needs defining.

3) Ensure compliance with local and state regulations.

Regulations may also require update.

4) All treatment needs maintenance.

From the simplest to the most sophisticated

5) Many homeowners do not maintain.

A non-budgeted item?

B HOW (alternate choices)?
1) Management by homeowner with inspection.

Simplest,
least
invasive

2) Management by contractor with (less) inspection.

Must be scheduled

3) Management by PSD by contract.

Must be scheduled

4) Direct management by PSD.

PSD employee and equipment
Note: For B(1) & (2) homeowner pays for each service
For (3) & (4) homeowner pays monthly service fee

C POLICY ISSUES FOR B (3) & (4)
1) Access required for homeowner property.

A turf issue

2) Who brings system to standard at start?
Can be an unbudgeted financial investment for the homeowner unless amortized
into monthly charges

3) Who pays for repairs/maintenance in continuum?
Can be direct charge to individual homeowner or shared equally among all
subscribers as a monthly charge

4) How do you deal with low income homes?

May be difficult unless universally amortized

5) How do you enforce?

If central water service, this could be cut?

D PROCEDURAL ISSUES
1) Commitment of representatives is a prerequisite.
Community must be sold on the idea usually means that a good PR campaign is
needed

2) New Ordinances may be required.
These may cover enablement, regulation, enforcement, permits, licence to
practice, design (prescriptive or performance based), easements and rights of way

3) A plebiscite may be required.

Depends upon local ordinances
Many homeowners would prefer a fully sewered service, despite the very high capital cost. It
may be easier to convince a community to accept managed.

Wastewater Management In Cabo Verde
Mr Antunio De Cassia Sousa Barbosa
Director, Directorate General of Marine Affairs, PO Box 7, S, Vicente, Cabo Verde
Tel: (238) 324-342, Fax: (238) 324-343, Email: dgmp@milton.cvtelecom.cv

Introduction
Cape Verde is an island State lying in the Atlantic Ocean some 300 miles from the African
continent and belonging to sub-Saharan region. This archipelago is a group of ten islands and
several islets. The total land area is 4.033 km2 and it has a coastline of 1017 Km. By
geographical coordinates its extremes points are 17� 12� N, 14� 48� N, 22� 40� W and 25� 22�W.
The islands are of volcanic origin and seem to
be on the ocean crust between 120 to 140
million years old. Cape Verde's natural
environment is deeply marked by insularity,
predominance of volcanic landscape with high
altitudes and steep slopes, and a differentiated
microclimate and vegetation characteristics,
which are a result of altitude variations and the
position in relation to the trade winds.
Droughts are well known in Cape Verde and
have been the most typical element in this
sahelean country. Matter of fact, this
characteristic is inscribed in almost all of the
country's cultural manifestations.
With exception of three most eastern islands �

Maio, Boavista and Sal - the country is almost
deprived of continental shelf. Actually,
considering depth up to 200 meters, the overall
continental shelf area is approximately 4.000
km2.
Cape Verde has a 200-mile exclusive economic zone with an approximate area of 750,000 m2
and is a country where development opportunities are limited due to low availability of drinking
water, its small surface area and geographical dispersion, and little availability of natural
resources. The strong demographic pressure on arable land (more than 400 inhabitants per square
kilometre on arable land), the limited natural resources and low technological development have
been factors of internal and external migrations. In effect, only 10% of the country's surface is
arable, that is about 4.000 acres, and agriculture production covers for only 10 to 20% of the
basic food needs.

The climate is tropical, mild and arid. The average annual temperature is 24�C, stable because of
the regulatory capacity of the ocean. The average surface water temperature is 23�C, with a
minimum of 21�C and a maximum of 27�C. There are two seasons in Cape Verde: the dry season
from November to July when the trade winds blows, and the rainy season from August to
October. The average rainfall per annum is a little more than 100 mm. This rain is erratic and
randomly dispersed, therefore once a while the rain is heavy.
The population according to 1990 census was 341.491 inhabitants and today it estimated to be
quasi - 400,000 people. Of the ten islands, all but one is uninhabited and the population
distribution is uneven. For instance, Santiago, the biggest island has over 200.000 people, which
represents more than 50% of population. On the other hand, Boavista, the third largest, has less
than 4.000 people. This unbalanced distribution of population causes very high investment per
capita as far as basic infrastructures are concerned. See population table annex 2. It might be
worthwhile mentioning that Cape Verde has a very big Diaspora, comprising more than 700.000
people. Most of this group resides in United States and in Portugal.
In general the cape-verdean economy is characterized by a structural imbalance between national
production, on one side, and consumption needs and capital building on the other. This economy
is very dependent on imports, which is at the bases of the strong structural imbalances. In the
same manner, the economy depends greatly on the outside world in order to satisfy the needs in
terms of consumption and investments.
Cape Verde's great economic dependence, illustrated by the dependence of the investment
budget of 80/90 percent on foreign aid, is one of the main aspects of a reality which reflects the
almost total absence of natural resources. The annual GNP per capita is estimated at US $803.00
but for 30% of the poorer population this amount lowers down to US$100.00. The sector
distribution of the GNP shows the importance of the growing tertiary sector that constitutes 60%
of the GNP. The agriculture and animal raising (livestock) sector since 1989 contributed only 6
to 10% percent of the GNP.
Administratively, Cape Verde is divided into 17 Municipalities with limited empowerment and
greatly controlled by the central government. This fact stems from political disputes among the
municipalities that do not belong to the same political party as the Government. With exception
of Santiago (6), Santo Ant�o (3) and Fogo (2) every island is a Municipality in itself.

Environment in Cape Verde
The Constitution of Cape Verde dedicates to Environmental Protection issues. This Constitution
of 1992, article 70, chapter II, part 2, determines that the State, the departments and the
environmental protection agencies, have the responsibility of promoting the preservation and
rational utilization of natural resources.
Environmental issues have been gaining some attention lately and mid eighties may be
considered as reference point. The public awareness is low and only recently that some
environmental education has started taking place in primary school.

With regard to marine living resources the biomass of cape-verdean waters is estimated to be in
excess of 100.000 ton, two-third of which is associated with the islands of large continental shelf,
namely, Sal, Boavista and Maio. Of this total, 35.000 tons represents demersals species and
65.000 tons pelagic ones. Additionally, Cape Verde is located on route of migrations of tuna fish;
even tough several species are sedentary. In some coastal areas sea turtles have nests whereby
they do the breeding. Green and rose lobsters are abundant.
The flora is composed of 240 aboriginal taxa, being 84 of these found exclusively in this
country. There are a few endangered species that can be found in some islands. Presently about
45 aboriginal taxa are extinct due to deforestation. The terrestrial fauna is mainly composed of
birds, reptiles and arthropods. Out of the 36 bird species that reproduces in Cape Verde, 17
(47,2%) are in danger of extinction. Seven of 28 reptile taxa in Cape Verde are also in danger of
extinction. The entomological aspect of the cape-verdean fauna, one can account for 470
coleopteran species, being 155 found exclusively in this region. About 301 (64%) of this species
are in danger of extinction and, it is presumed that 70 species are extinct.
The environmental legislation is incomplete and recent. In 1993 the basic law of the
Environment was enacted � Law 86/IV/93. Several disperse pieces of legislation is into force but
does not cover all aspect of environment protection. It seems that the lawmakers are aware of
this handicap and some proposals are now being drafted to fill the gaps that still are in place.
Exception is made relative to Law 79/III/90, which defines the marine protected areas. However,
this law still requires regulation.

Water Resources and Sanitation
As stated above, water is scarce and in fact it is the biggest obstacle to development. Since early
seventies the source of water started to be desalinization. The first island to accommodate such
plant was S. Vicente. And since then three more islands are now served with desalinated water,
Santiago, Sal and Boavista. The total production of desalinated water in 1997 was 1,681,000 m3.
The ground water is depleting by the year and its sustainability can not be guaranteed. Indeed in
1984 the Water Code was enacted whereby the State nationalized all water resources as means to
control its use and fair distribution to all.
On the other hand, with exception of desalination, the other sources of water are precipitation
that occurs during the months of August and September, water tables and springs. The average
annual precipitation varies with the topography and altitude of the islands. Therefore, the
mountainous islands of Santo Ant�o, Santiago, Fogo and Brava have the highest average
precipitation. Water supplied by rainfall is disturbed as follows: 67% is lost by evaporation, 20%
is lost by runoff and 13% replenishes the ground water table. There are about 124 million
m3/year of ground water and only a fraction, estimated to be around 65 million m3/year, can be
technically explored. This withdrawal is lowering this value to 44 million m3/year during the dry
years (1970-1990).

If the water is scarce, one can conclude that the production the residual water is low. Regrettably
the concept of sanitation versus the public health is not very well formulated in the policies.
Cape Verde has two main cities, Praia and Mindelo, the former is the capital with a population of
90.000 people, while the latter has a population of 70.000 people. Additionally it has several
secondary urban centers, with population varying from few thousands to 25.000 people.
The country faces a situation of complete absence or great need of basic sanitation infrastructures
considered indispensable for the quality of the lives of the people. These needs, besides
conditioning the normal development of the sectors of the social and economic life, have serious
implications in the public health.
With regard to sanitation, the country's global coverage is of 25%, thus distributed: sewage
system (8%) bore sewers (5%), dry latrines (1%), others 11%. The current rate of coverage of the
sewage network in the city of Praia is 9% and in Mindelo 65%. None of the secondary urban
centers have sewage network, bore sewers are the only existing sanitation system in these
centers. Living conditions are very critical, only 20% of the homes have a bathroom with
sanitation facilities.
In Praia, in 1997 less than ten percent of the population benefited from the sewer system,
however the system is under expansion. It is expected by the end of 1999 to increase that figure
to 20% percent and potentially this figure can go up to 27%. At present the major obstacle to be
connected to the sewer network seems to be the cost, which varies from US $150 to $300
depending on the value of the house. This shortcoming causes an under utilization of the sewer
network whose capacity is designed for an intake of 647 m3/hr.

Wastewater Treatment Plant of Praia
The treatment plant is of primary type and located in Palmarejo, a valley situated some 15 meters
below the residential area, and it comprises the following:
An intake structure followed by two screening devices. The first one is made of vertical bars
with a shape of an arc with spacing of 50 mm and the second one with spacing of 20 mm. The
first screening device is manually cleaned and the other is mechanically cleaned. These devices
remove big solid materials that are found in the sewage. Additionally the system has an aired
sand removal device of square cross section with a capacity of 36,5 m3. A movable skimmer is
fitted in a settling tank of rectangular shape, which in its forward motion skims the scum and
other fat components of the sewage, and on the opposite direction skims the sludge in the bottom
of settling tank.
At the end of the system a holding tank is used for disinfecting of the effluent prior to discharge
in cases of emergencies, i.e. cases of cholera, diarrhea, etc. The disenfection is carried out by a
solution sodium hypochlorite. An underwater emissary located some 700 meters from the station
discharge the effluent to the sea through a diffuser.

The treatment of solid part is taken care by a sludge digester of anaerobic type working at
atmospheric temperature. This digester is of conic shape and is followed by a pressing filter,
which dehydrates the treated sludge after mixing it with a solution of polyelectrolyte.
The station in Praia was designed with the following parameters:
Parameters
Units
1995
2005
Inhabitants covered
Inhabitants
24794
121135
Inhabitants connected
Inhabitants
15214
101124
Specific load
l/cap/day
85
120
Average daily flow
m3/day
647
8494
Average flow
m3/hour
27
354
BOD

5
Specific load
g/cap/day
30
40
Average concentration
mg/l
705
475
Total carrying capacity
kg/day
456
4044
DRY

MAT
TER
Specific load
g/cap/day
30
60
Average concentration
mg/l
705
710
Total carrying capacity
kg/day
456
6066
The last available record, in March 1998, indicated an average inflow of 14 m3/hr with a
maximum of 24 m3/hr.
Routine operation of the plant consists of the following:

Pumping of sludge from settling tank to the digester every morning for 10 to 15 minutes.
The sludge in the digester remains there for two to three months. Afterwards it is removed
and dehydrated by the pressing filter and disposed of by burying.
Pumping compressed air every morning and afternoon for 3 hours provides air for the sand
removal device.
The station came into operation in September 1997 and is run by staff of six persons.
The wastewater are controlled analytically only with respect to physical parameters �
temperature, pH and conductivity � and suspended solids. A new laboratory facility is to be built
in the near future. It is expected that when this lab come into operation it would be possible to
control the wastewater in its chemical and bacteriological aspects.
The complete treatment cycle lasts less than 24 hours and it varies according to the load, i.e. the
smaller the load the bigger is the retention time.
The plant in Praia was conceived to accommodate an expansion and to be converted to a
secondary treatment plant.

Wastewater Treatment Plant of Mindelo
In the city of Mindelo, S. Vicente 65% of population is connected to the sewer network. The
amount of wastewater the station can handle is about 2,200m3/day, but at present it receives
1,700 m3/day.
The wastewater treatment plant is of secondary type. Before the effluent reaches the station it
undergoes a primary treatment at four different pumping station located at several points in the
city. This treatment consists of screening in a mesh filter. Screening devices are used to remove
coarse solids, such plastic, metals, rags, paper, and the like from the wastewater. The primary
purpose of screens is to prevent clogging of valves, nozzles, channels and other appurtenances.
For example, the screening device at Caisim (one of pumping station) is manually cleaned twice
a week. The solid waste removed from bars is today thrown just outside the pumping station near
the sea bank, so that the sea may dispose of it at tidal changes. Obviously this practice is a bad
solution since this sludge, besides posing a public health threat, it is also harmful to the
environment to say the least.
In case of malfunction of the pumping stations raw sewage is directed straight into the sea.
The effluent of primary discharge treatment contains unsettled solids, organic matter, and
pathogens, i.e. organisms which causes diseases, which must be removed before the water is
discharged. The primary treatment is therefore followed by a biological treatment step. The
biological treatment units at Ribeira de Vinha consist of a pond system of three kinds: anaerobic,
facultative, and aerobic also called maturation pond.

The active agents in biological treatment are microorganisms of which some by nature are
present in the wastewater. To this group belong amongst other, bacteria, protozoa and algae, of
which bacteria are the most important organisms.
The treatment step has to be constructed to favor microorganisms in the effluent, since they are a
source of organic carbon. If the effluent from the biological treatment step is to be used for
irrigation the amount of organic carbon has to be reduced or the roots of the crops will be
suffocated since the oxygen in the water is used for consumption of carbon. It also important to
reduce the amount of pathogens, otherwise these may transmit diseases to the people working in
the field and to consumers of the crops.
To achieve the above mention quality of water/effluent, the treatment processes in ponds are the
same as the purification processes of water in nature. This is done by leading the wastewater into
ponds where microorganisms purify the wastewater. The water is detained until satisfactory
treatment is reached. Complete cycle lasts for 21 days. Depending on the main biological activity
that is taking place in the pond, they are called:
o Anaerobic ponds � dissolved oxygen is absent which is accomplished by
increasing the pond depth, wastewater is anaerobic when it enter the treatment
plant,
o Facultative ponds � at the bottom of the pond dissolved oxygen is absent thus
creating anaerobic conditions in the bottom sludge, in the upper water layers of
the pond air is allowed to mix the water creating an aerobic zone, also the algae
produce oxygen when creating new cell algae,
o Maturation ponds � dissolved oxygen is present at all depths, this is made possible
by making the pond very shallow and designing the surrounding areas beneficial
for air mixing into the water, and as said above algae produce oxygen when
creating new cell algae.
Wastewater treatment in pond system is a simple method of treating wastewater, since it does not
require complicated mechanical devices and need very little maintenance compared with other
types of biological wastewater treatment. It is suitable to use pond systems for treatment both
municipal and certain industrial wastewater, though this category is scarce or non-existent at
present.

Anaerobic pond
The main treatment process in an anaerobic pond is anaerobic degradation and mineralization of
organic matter by bacteria producing methane, carbon dioxide and hydrogen sulfate.
The anaerobic pond reduces the organic load to a level, which is suitable for further treatment
with facultative and later aerobic ponds. The main advantage with anaerobic treatment of heavily
organically polluted water is that the production of biological sludge is low in anaerobic ponds
compared with the production of biological sludge in aerobic ponds.

Complex Facultative

Organic
Methane

Methane
organic
and
acids
forming
matter
+ anaerobic Aldehydes

bacteria
Carbon dioxide
bacteria
Alcohol
+
Small amounts of
Carbon
other gases
dioxide
Hydrogen

Basic Anaerobic Reactions - Facultative Ponds
In facultative ponds the most complete treatment results are gained as far as single ponds are
concerned. In ponds systems which includes both aerobic and anaerobic ponds, a facultative
pond is necessary in between them to prevent anaerobic conditions in aerobic ponds. The basic
treatment steps in a facultative pond are:
� Sludge separation by sedimentation,
� Anaerobic degradation and mineralization of sludge by bacteria, producing methane,
carbon dioxide and hydrogen sulfate,
� Aerobic degradation of organic matter by microorganism, mainly bacteria,
� Biological growth of algae producing oxygen needed for aerobic biological degradation.
The algae will then either be degraded by microorganisms or sediment as sludge,
The treatment processes that take place in facultative ponds, are of aerobic, anaerobic and
facultative nature. The cooperation between these biological processes is complex, but may be
described as follows. Figure 1 illustrates the main biological activities in a facultative pond.
In the aerobic zone aerobic bacteria and algae live in symbiosis as in an aerobic pond, i.e. the
algae produce oxygen which the aerobic bacteria need to degrade organic matter, the bacteria in
turn release carbon dioxide which the algae utilize together with sunlight to create new algae-
cells.
When the algae die they will settle, together with other settled solids present in the water, to form
bottom sludge. Anaerobic bacteria decompose the sludge since no dissolved oxygen is present at
the bottom of the pond. The anaerobic decomposition yields inorganic nutrients and odorous
compounds, e.g. hydrogen sulfate and organic acids. The odorous compounds will be oxidized in
the aerobic zone of the pound thus preventing their emission to the atmosphere.
In the facultative intermediate zone facultative bacteria are decomposing organic matter.
Facultative bacteria are bacteria that adapt to the amount of dissolved oxygen in their
surroundings. When dissolved oxygen is present facultative bacteria will work as aerobic,
otherwise they work as anaerobic bacteria.

Maturation Pond (Aerobic Ponds)
Aerobic ponds contain algae and bacteria in suspension. The bacteria break down the organic
matter in suspension and produce carbon dioxide. The products of the bacteria degradation,
especially carbon dioxide, and solar energy are then utilized by algae to create new alga-cells
while releasing oxygen to solution, which is then used by bacteria. Bacteria and algae live in
symbiosis in the aerobic pond, figure 2. Natural air mixing also provides oxygen, but to maintain
aerobic conditions at all depths dissolved oxygen has to be added by photosynthetic activities.

Design Parameters
The wastewater treatment plant at Ribeira de Vinha consists of seven ponds. See Annex 1. Two
anaerobic ponds running in parallel; one facultative, three maturation ponds which may be run
separately, in series or in parallel; and one pond at the end of the biological treatment to store
treated water before it is transported to the water reservoirs. The site is prepared for the addition
of one anaerobic, one facultative, and one maturation pond.

Table 1. Specifications of the Ponds
PONDS
DEPTH [ m]
AREA [m2]
VOLUME [m3]
A, B, C
2.5
1 000
2 500
1, 2, 3, 4
1.5
5 590
9 600
5
1.0
11 220
12 000
6
1.0
8 170
8 800
7
1.5
2 420
3 750
The area given in Table 1 is the area of the pond. Since the pond has sloping sides the volumes is
larger than the area multiplied by depth of the pond.

Operation of the Plant Since Construction to Date
When the plant was constructed, the first phase was designed for a daily maximum inflow of
2250 m3/day, but since COD/reduction of 80% in the facultative pond is desirable, the plant is
only to cope with 1900m3/day. However, in 1992 the amount of wastewater collected did not
exceed 400 m3/day, the volume of the ponds was far too large. This resulted in longer detention
time than wanted, and that together with large pond area resulted in great evaporation. By its
turn, due to large evaporation the salinity in each pond increased which disturbed the biological
processes and made the treated water less suitable for irrigation.

In order to attempt to find a solution to the problems found several corrective actions were taken
since then. At present some 1700 m3/day reaches the plant, and the ponds were set up to be
working in parallel and subdividing them also reduced its capacity.
The sewage network has been working normally and the maintenance staff has been able to
overcome the daily problem they find. Daily cleaning is carried out at the pumping station, and
weekly at the site. Physical control is done on weekly base in order to assess the quality of
wastewater at inflow so preventive measures can be taken to avoid further damage of the
network as a whole.
On the other hand, some difficulties are found, namely shortage of personnel to be on stand by
on daily basis to attend the demands that occurs, low inventory of spare parts, lack of trained
labor, poor behavior of customers, and high cost of service provided (connection to the network)

Laboratory Facilities
A new lab was recently built and it is fitted with equipment to control chemical, physical, and
bacteriological parameters of wastewater, soil and products.
The plant operates with a staff of 33 personnel, and at present is managed by the Municipal
Authorities of S. Vicente.
Treated effluent is then pumped to six holding water reservoirs located some 3 km from the
treatment site where is supposed to be used for reforestation program and irrigation in
agricultural projects. In this regard these projects are now simply on stand-by due to lack of
understanding between the municipal authority and the central Government.

Septic Tank
In the secondary urban centers where there is no sewage network, the majority of houses use
septic tanks as means of sanitation.
The system consists of two tanks working in series - a receiving tank and an absorbent tank. The
first one is made of concrete structure, connected via a siphon to the second one which is made
of loosen stone.
The principle behind the functioning of this system is that the sewage upon entrance of receiving
tank undergoes an anaerobic biological treatment and the liquid phase of it moves on to the
absorbent compartment for infiltration to the ground. Special trucks remove sludge that
accumulates in the receiving tank roughly every four years.
Anaerobic conditions in the receiving tank must be created and maintained. The second tank is
aerobic and this condition is achieved by ventilating the tank using a gooseneck pipe open to the
surrounding atmosphere preferably located at the highest point of the house.

Precautions should be taken to avoid the disruption of the process, namely, keeping the receiving
compartment sealed from air leakage, and avoiding the dumping of soap water directly into it
since this kind of wastewater might have some ill effect on the living organisms in that
compartment.
Regrettably the operation of septic tanks poses several problems to the users. First of all, the
designing of the system does not follow strict technical recommendations; often the receiving
tank ends up working, as a holding tank for sewage, in this situation cleaning becomes necessary
more frequently. Secondly, the location of absorbent tank is located close to fresh water cistern
posing a serious threat to public health in case of contamination by pathogenic and other
organisms. This situation arises when there is low availability of surrounding area and in most
cases as consequence of ignorance and lack of enforcement of the rules and regulations.
Lately, some houses, especially those constructed on the slopes are conceiving systems whereby
the wastewater from showers and laundry - called soap water - is segregated from other source of
domestic water and channeled to a filtering unit for re-use in irrigation of local gardens. The
system works by using gravel, sand, porous stones and foam as filtering elements. The water
flowing from those above-mentioned sources is left to settle in a tank where fats can float and
then be removed. When it has reached a certain level it is siphoned to the filtering element. The
application of this system is being encouraged since it contributes to lowering the consumption
of fresh water and therefore making it available to more people and generating higher savings to
them besides creating some green areas.
As a matter of fact, in Sal Island the hotel resorts located in Santa Maria � about five � have
facilities whereby domestic wastewater can be treated locally and later re-use in irrigation of
gardens.

Industries and Industrial Wastewater
The country is practically deprived of industries. Exception is made to a brewing industry (in
Praia) a small soap factory (in S. Vicente) and several very small units such fish processing in
tins, filling of soft drinks, and some textile factories. In fact this is a good reflection of Cape
Verde dimension, smallness.
Therefore when we talk of industrial wastewater very little can be said. The brewing industry
located in Praia, some 150 meters from shoreline produces on average 60,000 hl of beer per
annum. Being a major consumer of water, it is inevitable that the brewing industry is also a
major effluent producer. Regrettably, the effluent produced in this plant is discharged directly
into sea without any form of treatment. The plant has its own installation to produce fresh water
and it generates more than 25 m3/day of wastewater.
Since the brewing effluent is essentially rich in organic matters, this discharge into sea tends to
deplete the dissolved oxygen present in the nearby water endangering so the marine life that
exists there. Worst of all no prior analysis is carried out to assess the real impact of this

discharge. The emissary is located in a closed bay where the port activity is very intense and one
may say that that area is a sacrificed area.
Due to the increasing environmental awareness of the society, the management is looking into
changing his attitude toward this existing practice. The possibility would be either to connect to
main municipal sewer network or to recycle/treat the water for irrigation purposes. At present,
the biggest concern regarding the effluent discharge has to do odor problems. This obnoxious
odor is being dealt with by placing a mechanical filter on the stream of discharge to retain some
malt that otherwise would find its way into sea and further the fermentation process. However, at
present the problem still persists.
The soap factory located on S. Vicente Island is a small unit producing 1,620 tons of soap bars
per year. The daily consumption of water is about 15 m3, of which only 2 to 3 m3 are wastewater.
This residual waste is channeled to septic tank of about 40-m3 capacity. No previous treatment is
done prior to dumping. Concerns of contamination of ground were never taken into account.
Fortunately, there exists no wells in the vicinity of the septic tanks, and as a matter of fact this
Island is not furnished by ground water at all.
Sludge and other solid material are removed from septic tanks every two to three years by special
truck.
Desalinization plants in S. Vicente, Santiago, Boavista and Sal discharge their brine directly into
sea. This brine has a temperature of 50�C and the salinity is of 60 mg/l.
Finally, huge amounts of superficial water from precipitation find their way into the sea through
storm drains and in form of floods. However, this situation arises only when it rains, which is
rare.

Conclusion
It stems from what is said above that the management practice of wastewater in Cape Verde is
poor, very old fashion and it needs reviewing to be coherent with new demands of an
environmental mind society.
A weak point for most environmental projects and programs is that they involve many
government agencies with overlapping responsibilities. Sorting out this complicated web is very
difficult, as it requires strong political commitment.
There is an urgent need to regulate this sector and to provide means to the central and local
authorities to enforce and implement relevant legislation. This activity may be regarded as a
challenge to everyone involved in catering for a sound environment since the cumulative effects
of poor environmental management might cause some irreversible damage of our scarce
resources.

Household Systems for Wastewater Treatment:

Household Systems for Wastewater Treatment
Goen E Ho and Kuruvilla Mathew
Remote Area Developments Group, Institute for Environmental Science, Murdoch University,
Murdoch, Western Australia 6150
Associate Professor Goen Ho
Tel: (61-8) 9360-2167, Fax: (61-8) 9310-4997, Email: ho@essun1.murdoch.edu.au
Dr Kuruvilla Mathew
Tel: (61-8) 9360-2896, Fax: (61-8) 9310-4997, Email: mathew@essun1.murdoch.edu.au

Introduction
Isolated dwellings present their own problems of sewage disposal. The septic tank has
conventionally been used to treat the sewage. It usually consists of one or two tanks for settling
of solids with the overflow disposed via subsurface soil percolation. Depending on soil
permeability a soak well is used in very permeable soil, whereas a trench is used where the soil is
less permeable allowing for more infiltration area. Settled solids in the tank(s) undergo some
anaerobic decomposition, but have to be emptied on a regular basis. Properly designed a septic
tank may perform satisfactorily in unobtrusively conveying wastewater away from a dwelling. It
can, however, pose health hazards in rocky or tight clay soils resulting in ponding of untreated
sewage. More generally septic tanks contaminate groundwater with human pathogens, nutrients
(nitrogen and phosphorus) and other pollutants disposed with domestic wastewater. The
problems are accentuated where groundwater is close to the surface, or withdrawn for water
supply for the isolated dwelling.
There are now a variety of options for wastewater treatment, disposal and reuse for isolated
dwellings. Such systems can produce an effluent quality equal to or better than a conventional
treatment plant. They may also be more cost effective than reticulated sewerage in rural and
semi-rural areas besides isolated dwellings of remote areas, because extensive piping and
pumping is avoided. There are also questions from the point of view of a local community
particularly in developing countries besides the affordability of the chosen system for them, such
as control over technologies that have the potential to influence the dynamics, form and
autonomy of the community into which they are introduced. In addition there are now growing
environmental and social pressures to consider reusing wastes and to begin introducing systems
which are sustainable in the long term.
This section will discus the criteria to be considered in general in the process of selection of a
particular technology for isolated dwellings and then describe a few technologies which are
approved to be used in Australia to illustrate technologies that can be applied in other parts of the

world. Use of local materials, modified design to suit local conditions and preference of a
community should be taken into account when determining what is best for a particular case.

Criteria for Selection
During the selection process each option must be considered in terms of its ability to satisfy the
following criteria. But in addition the extent of treatment necessary, the soil type or the site
requirements and personal or community attitudes and preference should also be considered.

Reuse of Resources
Wastewater is often considered a source of public health problems to be disposed of and not as a
resource. The choice of disposal and treatment system is usually governed by the disposal
strategy. Reasons for reuse and options of reuse are well documented (Odendaal, 1992, Mathew
& Ho, 1993). It is possible to use the treated wastewater and the sludge if proper treatment
procedure is adopted while at the same time satisfying the guidelines for reuse (NHMRC, 1987;
ANZECC, 1992).

Protect the Environment
Protection of public health is of the reason for treatment of sewage. Protection of the
environment should also be considered. The conventional system of on-site disposal of
wastewater is the septic tank and soil absorption system. The effluent from septic tank after soil
treatment does not usually meet the criteria for maintenance of groundwater quality and hence
needs further treatment (UWRAA/AWRC, 1992). Nutrient removal may become necessary in
many situations where nutrients can cause pollution either directly by, for example, nitrate in the
treated wastewater or through euthrophication of the receiving water.

Simplicity of Operation
A system sophisticated in its technology and control may tend to be complicated in operation.
Frequent servicing and regular checking may become inevitable in operating an on-site treatment
plant. While aiming for the best performance possible a system with minimum operational
requirements and relatively easy and simple to maintain should be preferred.

Minimum Use of Chemicals
Chemicals have been used for phosphorus removal and disinfection. Biological phosphorus
removal is to be preferred to chemical removal process. Disinfection by ultraviolet radiation
should be considered in place of chlorination. Sub-surface micro-irrigation, for example, may not
demand disinfection to the level it is necessary at present.

Other general aspects such as installation cost, maintenance expenses, aesthetic considerations,
durability of the equipment and low energy consumption should also be considered in the
selection of a system.

Systems Designed for Low Water Usage
Domestic sewage generally consists of wastes produced from the toilet, kitchen sink, bath and
shower, wash basin and laundry. Toilet waste, generally referred to as black water, makes up to
25-30% of the total flow, while the other wastes comprise 70-75% of the flow is collectively
referred to as grey water. The design of low water use systems attempts to reduce the amount of
water, and black water may, for example, be reduced significantly producing only sludge. The
black water contains the major portion of biochemical oxygen demand (BOD), suspended solids
(SS), bacteria and nutrients. So if the black water is treated separately then treatment of grey
water alone becomes easier and less complicated. The potential of pollutants being transported
by the water in the black water is simultaneously significantly reduced, because water is
generally the conveying medium for the pollutants.

V.I.P. Toilet
The Ventilated Improved Pit (VIP) toilet is a product of the Centre for Appropriate Technology
(CAT), Alice Springs, Australia. Even though this is a pit toilet, its special construction ensures
minimum odour and fly problems. It is possible for a family of five people to use the same unit
for 10 years (Walker, 1985). In Australia this has been found to be suitable for camping places in
national parks, main roads department highway rest sites, and remote communities.

Composting Toilet
Composting systems do not require any water connection, periodical pumping out, chemical
dosing or on-going maintenance. It converts the waste with the nutrients in it into garden
compost. It can be installed for single dwellings or community ablutions irrespective of the soil
type of the area and should not create any environmental pollution. Three composting toilets
approved by the Health Department of Western Australia are described below.

Clivus Multrum
The Clivus Multrum consists of a sloping, fibreglass compost tank which has been divided into
an upper section for the treatment of fresh wastes and a lower section for the treatment of mature
compost. The toilet seat is placed on the top of the tank. A vent pipe fitted with a fan to force the
flow of air to the outside of the toilet is connected to the tank to keep the room odour free. There
is a liquid drain which removes the excess liquid to keep the waste dry enough for composting.
There are two inspection doors to provide access to both chambers. This can have multiple toilets
and urinals with a capacity for up to 40 - 120 people. The pile should be inspected weekly to

ensure adequate moisture levels and to add a bulking agent if necessary. It is suggested to level
the pile quarterly and remove the compost from the lower chambers annually (Clivus Multrum,
1990). Vent-screens and pest strips may be used for pest control with a possibility of using a
biodegradable pesticide in extreme circumstances.

Rota-Loo
Rota-Loo is designed for use by 6 - 8 people and hence is small and compact. It consists of four
separate composting chambers in a circular container. Two of the chambers can be used
simultaneously providing the opportunity of having two toilets using one housing unit. An air
vent with a fan is connected to the main chamber to make sure continuous air flow is maintained.
There is a heating element at the bottom of the chamber which keeps the temperature suitable for
composting irrespective of the outside temperature. When one chamber is full the container is
rotated thus providing the opportunity for maturing the compost. It is suggested to remove the
compost annually and adjust its use to ensure enough time for composting (Rota-Loo, 1991).

Dowmus
The toilet seat of the Dowmus system is connected to a circular composting chamber of about
4.3 m3 which is of a sufficient volume for a family of five. It has a ventilation pipe with a fan to
exhaust air from the bottom of the tank providing air flow through the compost. The compost can
be extracted using an auger provided at the top of the tank towards one side. The Dowmus is
partially filled with active compost at the time of installation and inoculated with beneficial soil
organisms in particular tiger and red composting worms (Dowmus, 1993). There is no heating
element and the system is not intended to operate above 350C, to protect the worms. The process
depends more on soil organisms and worms rather than on the thermophilic microorganisms for
composting. It can also take other household organic matters provided they are cut into small
pieces. A family of five people can use this system for a few years without having to remove the
compost.

Vermi-processing Toilet
BERI (Bhawalkar Earthworm Research Institute) vermi-processing toilet (BVT) has been field
tested for 8 years in India and found to be a novel low water-use toilet for safe processing of
human excreta without odour and fly problem. The toilet pan is directly connected to a tank of
1m x 1m x 1m which has a removable cover slab with ventilation holes. This can serve a family
for about three years. BVT is started off by putting 5 kg of vermicastings in the pit (Bhawalkar
and Bhawalkar, 1991). The operation of the toilet employing the pit is very simple and hygienic
as the human excreta will be completely converted to vermi castings - a resource much needed
for soil.

Aerobic Treatment Units
The common practice is to treat black and grey water together. Even when the black water is
treated separately the grey water has to be treated by a system which satisfies the selection
criteria described above. A number of such systems now available are listed in Table 1.
TABLE 1: Approved Household Aerobic Treatment Units in various States in Australia

NSW
SA
VIC
QLD
TAS
NT
WA
Envirocycle �
� � � �
�
Supertreat
�
�

Biocycle
�
� � �

�
Clearwater
�
� � �

�
Biomax K
�

Biotreat
�

Garden Master
�

Model D10
�

Parco Beaver
�

�

Aerotor

�
Pending

Biorotor

�
�

Turbojet

�
�

Aquarius

�
Ecomax

�
Envirotech

�

NSW = New South Wale ; S
s
A = South Australia; VIC = Victoria; QLD = Queensland; TAS = Tasmania, NT = Northern Territory;
WA = Western Australia.
These systems have a pre-treatment module similar to a septic tank which is for primary
sedimentation and anaerobic decomposition. The recommended volume of 3 days storage for a
septic tank (HCV, 1979) is followed by most of the systems. Domestic on-site systems receive
wastewater usually as slug flows rather than as a constant flow. So the volume of the septic tank
should be large enough to prevent the displacement of settled solids to the next chamber.
The most significant unit is the aerobic treatment chamber where the biological treatment
process takes place to provide water quality to the secondary effluent standard. This is due to the
effective contact between the incoming waste and bacteria in the aeration tank. Due to the slug
flow in the small treatment units it is possible that the inflow may not achieve sufficient contact
with treatment bacteria. So most of the systems operate with bacteria growing on fixed media

which provide a longer contact time and less chance of bacteria washout, thus providing greater
opportunity for removal of organic materials from the liquid. In a trickling filter or biofilter
especially with new types of filter media with high availability of oxygen high removal rate is
achieved within a shorter time. On the other hand in activated sludge system to achieve
satisfactory level of treatment the wastewater has to be kept in the tank for several hours. Both
processes are applied in different aerobic treatment units.
A secondary settling tank removes the suspended matter producing effluent with a secondary
effluent water quality. The wastewater at this stage will normally have over a hundred thousand
coliform bacteria per 100 ml which should be reduced to 10 per 100 ml. Most aerobic treatment
units use chorination for disinfection.
The sludge produced in the secondary sedimentation tank is recycled to the septic tank for
further treatment and storage. Desludging of the tank is required regularly, either small amounts
quarterly or substantially every 3 to 4 years.
Nutrient removal is optional for aerobic treatment units at present. There are units available
which remove the nutrients with many organisations being involved in further research in this
area in Australia.
Five treatment systems approved by the Health Department of Western Australia are described
here as representatives of the available systems. These systems incorporate state of the art
treatment techniques available at present.

Envirocycle
Envirocycle in an aerobic treatment unit designed to treat sewage produced in a household of
five people. This system has multiple treatment chambers based on the activated sludge process
(Envirocycle, 1993). This is a circular unit with two primary settling chambers, two aerobic
chambers, a clarification chamber, a chamber for chlorination and storage to provide enough
contact time, and a chamber for storage and pumping for final disposal. The final effluent after
secondary clarification and chlorination is used for spray or trickle irrigation.

Biocycle
Biocycle is an aerobic treatment system which provides a secondary level of treatment to
produce an effluent which meets the 20 mg/L BOD and 30 mg/L SS effluent quality standard.
This is available in two sizes. The domestic model is designed for 10 people and the commercial
model is for offices, restaurants or other public institutions (Biocycle, 1990). The Biocycle
treatment system consists of a circular tank which is divided into four compartments (1) primary
settling and anaerobic digestion chamber, (2) aerobic chamber with fixed media and bubble
aeration facility, (3) secondary sedimentation chamber with the settled sludge pumped back to
the septic chamber, (4) chlorination and storage chambers. Chlorination is by tablet chlorinator

and the final effluent is pumped for irrigation when the volume reaches a pre-set level. The soil
at the irrigation area can be amended with neutralised bauxite residue for phophate removal.

Clearwater System
This is an aerobic treatment system which has two separate tanks. The first one is a circular tank
of 1.7 m dia and 1.6 m height which functions as a sedimentation and septic tank. The second
tank is a rectangular tank with three compartments, an aeration tank of 3.5 m3, a final clarifier of
1.0 m3 and a chlorination and storage tank of 1.7 m3 (Clearwater, 1990). The aeration tank has
panels for attached bacterial growth. The irrigation system is very similar to other systems such
as Biocycle.

Aquarius
Aquarius has five chambers (1) primary sedimentation and anaerobic digestion (2) anoxic
chamber for denitrification and chemical phosphorus removal (3) aerobic biological oxidation
including nitrification in subsurface biofilter and dentrification in submerged filter (4) secondary
clarifier and sludge recycle to the anoxic chamber (5) chlorination and storage for irrigation. In
addition to the required effluent standard Aquarius claims to achieve nitrogen and phosphorus
removal to below 1 mg/l. Aquarius is available in a variety of sizes starting from a domestic unit
for 10 people to units for industrial use or for small communities of up to 120 population
equivalent (Aquarius, 1993).

Ecomax
Ecomax consists of a conventional septic tank and dual leach drain or soakwell modified by the
addition of a filter bed of amended soil with a plastic lining. The filter bed contains neutralised
bauxite residue which has the capacity to adsorb phosphate, ammonium and heavy metals. The
filter bed is also a good bacterial filter. The treated effluent can be disposed of by soil percolation
or surface irrigation (Bowman and Bishaw, 1991). The system is designed to serve 4 - 6 people
for approximately 20 years, after which the filter bed needs to be replaced. It is possible to
increase the capacity of the system to serve more people or for an extended life span. This is a
passive system with no requirement for power, chemicals or periodical servicing, except for the
normal desludging requirements of the septic tank.

Comparison of Systems
Only systems approved by the Health Department of Western Australia are compared. As they
all meet the requirements for effluent and public health standards, only special features will be
discussed. All systems use a septic tank or equivalent and hence desludging will be necessary. A
septic tank and leach drain requires desludging on the average approximately every 3 years. If
the final effluent is used for irrigation no leach drain and its desludging is necessary. Table 2

summarizes similarities and differences amongst the systems, including initial costs and
maintenance requirements.

Conclusion
Municipal reticulated sewerage and treatment systems are generally the most desirable treatment
option because of the high degree of control which can be achieved and maintained over the
quality and disposal of treated effluent and sludge. But when the population density is not high
and if on-site disposal is possible it will be cheaper and allow better reuse options. At present
more and more on-site systems are becoming available which offer similar facilities to the larger
municipal treatment systems. On-site treatment systems can provide a higher degree of
protection for the aquatic environment due to the use of land disposal techniques which provide
additional level of treatment due to soil percolation before the treated wastewater entering the
water bodies. On-site irrigation allows use of the water for evaporation and plant
evapotranspiration and should not cause any pollution.
For a remote and isolated place a VIP toilet will be ideal. Composting toilets provide the ultimate
answer for water conservation and complete reuse of toilet waste if maintained properly. The
larger capacity of Clivus Multrum makes this system more suitable for large families or
industrial application. Rota-Loo being smaller with lesser maintenance demand will be more
suitable for small families. Dowmus produces a compost containing worm castings with a higher
fertilizer value. It is cheaper to install and cheaper to operate as it does not require heating.
Most of the treatment units are similar and produce effluent of similar quality. Clearwater system
has a separate septic tank and it is claimed that it needs to be desludged only every 10 - 15 years
against a normal period of 3 - 4 years. Aquarius produces a low nutrient effluent but installation
cost is higher; chemical use and yearly desludging operation also means higher operating cost.
But this is available in a variety of sizes serving up to 120 people. Ecomax is a passive system
which produces a low nutrient effluent but the filter media needs replacing every 15 to 20 years.
Where municipal systems are not available or costly due to low density of population on-site
systems provide a variety of options. A composting system for black water and an aerobic
system for grey water will assure complete reuse, conservation of water, desludging only
infrequently and reduction in potential nutrient pollution.

TABLE 2: Comparison of Systems Approved by the Health
Department of Western Australia
Treatment
Initial Cost ($#)
Maintenance
Comments
System
Requirements
1 Clivus

3000 - 5000 plus cost - Maintenance by the user
- Recycle of toilet waste as
for greywater
compost
Multrum
treatment system
- Cost of heating in cold areas
- A space of 2.5 m deep and
- Power cost of fan
1.5 m wide, 2.7 m long is
needed below the toilet
- Saves 30% on water use
2 Rota-Loo
3000 + cost for grey - Maintenance by the user
- Recycle of toilet waste as
water treatment
compost
system
- Cost of heating in cold areas
- A space of 1.5 x 1.5 x 1.5
- Power cost of fan
m3 is needed below the
toilet
- Save 30% on water use
3 Dowmus
2500 + cost for grey - Maintenance by the user
- Recycle toilet waste as
water treatment
worm compost
system
- Power cost of fan
- Circular area of 1.7 m
diameter with a depth of 2
m is needed below the toilet
- Saves 30% on water use
4 Envirocycle 5000 + installation
- Quarterly inspection
- Available in domestic and
commercial sizes
- Desludging every 3-4 years
- Power cost for pumps and
aerators
- Tablet chlorination required
5 Biocycle
5500 + installation
- Quarterly inspection
- Available in concrete and
fibreglass in domestic and
- Desludging every 3-4 years
commercial sizes
- Power cost for pumps and
aerators
- Tablet chlorination required

6 Clearwater
5500 + installation
- Quarterly inspection
- Available in concrete
- Desludging every 10-15 years
- Power cost for pumps and
aerators
- Tablet chlorination required
7 Aquarius
8000 + installation
- Quarterly inspection
- Available in fibreglass and
stainless steel in many sizes
- Desludging every year
- Removes nutrients
- Power cost of pumps
- Tablet chlorination and
chemical for phosphorus removal
8 Ecomax
5500
- Desludging every 3-4 years
- Removes nutrients
- Replacement of redmud filter
every 15-20 years
# Cost figures are in 1993 Australian $; 1 Australian $ is approximately 0.75 US $; Use of local
materials may reduce costs.

References
Aquarius (1993). "The Aquarius Micro Purifyer 600 SA Series". Western Wastewater Treatments
Pty. Ltd., 10 Rollings Crescent, Kwinana, WA 6167, Australia.
Australian and New Zealand Environment and Conservation Council (ANZECC) (1992).
"Australian Water Quality Guidelines for Fresh and Marine Waters" in National Water Quality
Management Strategy, Melbourne, Victoria, Australia.
Bhawalkar, V. and Bhawalkar U. (1991). "Vermiculture Biotechnology for Environmental
Protection, Sustainable Agriculture Wasteland Development" Bhawalkar Earthworm Research
Institute, A/3 Kalyani, Pune-satara Road, Pune, 411037, India.
Biocycle (1990). The Biocycle Systems. "General Information and Operation's Manual",
Biocycle Pty. Ltd., Suite 1/231 Balcatta Road, Balcatta, WA 6021, Australia.
Bowman, M. and Bishaw, M. (1991). "Ecomax Septic System. Explanatory Information. Ecomax
Waste Management Systems", Bowman, Bishaw Gorham Pty. Ltd., Subiaco, WA 6008,
Australia.

Clearwater (1990). "Clearwater 90 The Ultimate in Reclaimed Water" Clearwater Pty. Ltd., Unit
2/56 Carney Rd., Welshpool, WA 6106, Australia.
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Manual, Clivus Multrum Pty. Ltd., 31 Mandalay St., Fig Tree Pocket QLD 4069, Australia.
Dowmus (1993). "Common Questions Regarding the Dowmus Composting Toilet" Dowmus Pty.
Ltd., PO Box 51, Mapleton, QLD 4560, Australia.
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Tramore Place, Killarney Heights, NSW 2087, Australia.
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Collins St, Melbourne, VIC 3000.
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Area Developments Group, Institute of Environmental Science, Murdoch University, Murdoch,
WA 6150, Australia..
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Association Victorian Branch Conference on Wastewater Reduction and Recycling, Deakin
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(UWRAA/AWRC, 1992). "Affordable Water Supply and Sewerage for Small Communities
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Alice Springs, Australia, October 1985, paper 3 - 1.8.

Secondary Treatment Systems for On-site and
Decentralized Wastewater Management
Ted L. Loudon
Agricultural Engineering Department, Farrall Hall, Michigan State University, Farrall Hall,
E. Lansing, MI 48824, USA
Tel: (517) 353-3741, Fax: (517) 353-8982, Email: loudon@egr.msu.edu

Wastewater treatment processes are generally classified as either primary, secondary or tertiary.
Primary treatment typically involves settlement and floatation. Secondary treatment involves
aeration to promote the growth of aerobic organisms and treatment through the metabolic
processes of these aerobic organisms. Tertiary treatment implies advanced polishing including
more complete nutrient removal. In conventional onsite wastewater systems the septic tank
serves as the primary treatment chamber, and the soil system is expected to accomplish both the
secondary and tertiary treatment processes. In soils of fine particle size and low permeability, air
transfer rates are limited and effective secondary treatment may occur very slowly.
The introduction of a secondary treatment device between the septic tank and the soil absorption
system can greatly reduce the organic load to the soil and thus reduce the amount of treatment
required in the soil system. In addition, secondary treatment generally results in effluent that is
already somewhat aerobic, reducing the need for the oxygen transfer into the soil system.
Therefore, adding a secondary treatment system allows utilization of soils that are normally not
acceptable for onsite wastewater treatment. Secondary treatment will produce the following
results:
1. Reduce or eliminate clogging at the infiltrative surface of the soil
2. Reduce the pathogen content of the effluent applied to the soil
3. Reduce the total nitrogen content of the effluent going to the soil
4.
Prepare the effluent for additional treatment systems
5. Provide an effluent that is acceptable for surface discharge
following disinfection
6. Provide for recycling and reuse of the effluent.
The ability of secondary treatment systems to accomplish the first three of the above results is
generally recognized, but the validity and importance of the last three remain to be proven and
accepted widely. In some environmentally sensitive areas, i.e., high water table soils near surface
waters, phosphorous removal may be necessary beyond the level achieved with most secondary
treatment systems. Concern for phosphorous removal varies from one region to another.
However, once the secondary treatment system has removed most of the organic material in the
effluent, it may be possible to subject the effluent to adsorptive and/or a precipitative process to

further reduce the phosphorous concentration. Research is underway to test both laboratory and
field performance of low management methods designed to accomplish phosphorus removal by
these processes.
Some regulatory jurisdictions allow surface discharge of aerobically treated effluent following
disinfection where soil properties do not provide for reliable performance of soil absorption
systems. Secondary treated effluent from some treatment processes may be suitable for reuse in
irrigation and/or recycling through separate plumbing back to the house for flushing. With some
additional filtration and chlorination it may also be suitable for other uses.
Several recent papers have documented that secondary treatment reduces the organic loading on
soils sufficiently to virtually eliminate soil clogging, allowing the use of soils of much lower
permeability than would be acceptable for septic effluent (Siegrist, 1987; Tyler and Converse,
1995; Loudon and Bernie, 1995). It also allows higher loading rates and thus smaller soil
absorption systems. Effective secondary treatment will greatly extend the life of a soil absorption
system. Theory and experience accumulated over the past 15 years suggest that soil absorption
systems may last virtually indefinitely if consistently loaded with high-quality secondary
effluent. Secondary treatment may also be added where soil absorption systems are failing to
renovate and give additional life (Converse and Tyler, 1994). Another advantage of secondary
treatment is that various designs have been shown to provide high levels of nitrogen removal
ranging to over 90 percent total nitrogen removal.
Secondary treatment systems which are in use for onsite and small decentralized wastewater
treatment systems in North America include sand filters, artificial media filters, mini-trickling
filters, upflow filters, and package aerobic treatment units. Sand filters and aerobic treatment
units are in more common and widespread usage than the other concepts and will be discussed in
more detail.

Sand Filters
Sand filters of various designs have been used for wastewater treatment for many years.
Research and development over the past two decades have resulted in increased understanding of
the treatment process involved and provided improved pumps, controls, distribution systems and
other hardware to improve the performance and reliability of the technology.
Sand filters can be divided into several categories:
Intermittent (single pass)
Stratified
Bottomless (in trench)
Recirculating
Single pass sand filters: Single pass sand filters have been used increasingly for single family
homes in the northwestern United States for over 15 years. The sand filter is an added secondary
treatment device between the septic tank and the soil absorption system and requires a pump for

uniform distribution of septic tank effluent over the entire area of the sand filter. A typical cross
section for a sand filter includes a 24-30" deep layer of sand as the media that provides the
environment for the physical, chemical, and biological transformations necessary to achieve the
desired treatment level.
Suspended solids in the septic tank effluent that is pumped to the sand filter are removed by
filtration and sedimentation. Bacteria which live on the surfaces of the sand particles decompose
the filtered solids and, through a process known as autofiltration enhance the removal of
suspended material. Reduction in BOD5 and the conversion of ammonia to nitrate occur under
aerobic conditions through the action of the microorganisms in the sand bed. Some conversion
from nitrate to nitrogen gas (denitrification) routinely occurs resulting in up to 50 percent loss of
nitrogen in the process. The denitrification is probably the result of anaerobic bacteria coexisting
in micro anaerobic environments within the sand (Metcalf and Eddy, Inc, 1991).
To maintain a high level of treatment, aerobic conditions must be maintained within the upper
portion of the sand at all times. This is achieved by utilizing only shallow, sandy soil covers or
leaving the distribution stone open to the atmosphere. The pea stone layer in the bottom of the
sand filter is also thought to enhance air movement from the drain up through the sand filter to
further assist in maintaining aerobic conditions. Small, frequent doses of the effluent pumped
uniformly over the sand is important to avoid complete saturation (i.e., pores never filled) and to
maintain air within the pore space to support aerobic organisms.
In typical practice the distribution system is a small-diameter (3/4" - 1 1/4") pipe network
containing 1/8" orifices spaced on a 2'x2' or 2'x3' grid. Some designers include vent pipes
adjacent to the distribution pipes to assist aeration. Others cover the distribution pipes with a
chamber and utilize splash plates or spray nozzles to enhance distribution over the entire surface
area and enhance air transfer into the effluent.
Since small orifices are used in the distribution system (typically 1/8"), the use of an effluent
filter in the septic tank preceding the sand filter is highly recommendable. The filter will help
prevent things like hair and particulate material from washing out of the septic tank and thus help
protect the orifices from clogging.
The choice of the sand media is crucial to the performance of the sand filter. Sands are typically
specified by effective size and uniformity coefficient. The effective size (D10) is the grain size for
which no more than 10 percent of the particles are smaller, and the uniformity coefficient is the
ratio of the size for which 60 percent are smaller to the size for which 10 percent are smaller. For
single pass sand filters, an effective size in the range of 0.3 mm and a uniformity coefficient of
approximately 4 are recommended. Table 1 shows a recommended grain size distribution range.
Sand filter media must be free of any fines, particularly silt and clay size particles, which could
contribute to possible clogging of the sand pores.

Table 1. Recommended Sand Grain Size Distribution for Single-
Pass Sand Filters.
Sieve Size or Number
Grain Size (mm)
Perculent Finer
3/8" 9.5
100
#4 4.7
95-100
8 2.4
80-100
16 1.2
45-85
30 0.6
15-60
50 0.3
3-15
100 0.15
0-4
Single pass sand filters are sized based upon an assumed loading rate of approximately 1 -
1.25 gpd/sq ft. Thus a sand filter of approximately 360 sq ft would be needed for a three to four
bedroom house. The dimensions in Figure 1 show that the overall depth of the sand filter is 3.5 -
4' depending on whether a soil cover is utilized.
The sand filter should be dosed frequently with small amounts of effluent to provide the desired
treatment conditions. Dose amounts of less than 0.5 gal per orifice per cycle are recommended
for single pass sand filters. Operating the dose pump using a timer is preferred over operating on
a float switch or demand basis. Timer systems need float overrides to either run the pump more
to compensate for high water use periods or keep the pump from continuing to run periodically if
there is low or no water use.
Table 2 illustrates the expected performance of a sand filter compared to septic tank effluent
quality. A properly designed and managed sand filter should result in essentially clear water
effluent as indicated by the BOD5 and suspended solids data. In addition, nearly complete
nitrification should be achieved resulting in almost all of the nitrogen in the effluent being in the
nitrate form.
The stone in the top of the sand filter around the distribution piping is there to provide a very
porous matrix so that the water will move away from the distribution pipe rapidly. Typically the
stone is whatever the local code requires in sewage trenches. The most important characteristic is
that it be free of fines such as silts and clays that might wash down onto the sand surface and
contribute to sand clogging.

Table 2. Normal Ranges of Selected Wastewater Parameters in
Septic Tank and Sand Filter Effluents from Home Systems, mg/L.

Septic Tank
ISF
RSF
BOD5
130-250 2-10 2-15
TSS 30-150
5-12
5-20
NO3
0-2 15-30 15-30
NH3
25-60 0-2 0-5
Total
N
25-70 15-30 15-30
Total P2
5-15 2-15 2-15
Fecal Coliform
105-106
10-103
10-103
MPN/100ml
1 Lower values of BOD5 and TSS in the range are from tanks with effluent
screens.
2 Range is for locations with low phosphate detergent laws. Otherwise P
concentrations may range up to
30 mg/L.
Construction of sand filters may involve plywood walls to support the required waterproof liner
or, in cases where the soil is cohesive enough to stand as approximately vertical walls, the liner
can be directly installed in an excavation of the appropriate size. The earth walls must be fully
prepared to prevent puncture of the liner by roots or stones. In either form of construction, a 2-3"
layer of sand underneath the liner to protect its integrity is recommended.
Sand filter maintenance: Regular maintenance is important to assure long-term sand filter
performance. In construction, observation ports should be provided so that the infiltrative surface
at the base of the stone or the top of the sand layer can be viewed to determine whether ponding
is occurring at this level. It is recommended that at least one (possibly two or three) 4" inspection
ports be located around the sand filter, preferably near orifices, so that the sand surface can be
viewed periodically immediately following a dose of wastewater. If there is any tendency for
water to pond at the sand surface for more than a minute or two, either the dose is too large, the
sand too fine or the sand is beginning to clog. Sand clogging can also be an indication that the
wastewater characteristics are resulting in excessive organic loading to the sand filter.
An inspection port should also be extended to the bottom of the sand filter near the outside edge,
away from the drain. If the level of water ponded at the outside edge of the sand filter is more
than 2-3", the drain is beginning to slow down, probably due to clogging at the entry to the drain.
Any indication of clogging at either the sand surface or the drain indicates the need for
maintenance. If the clog is organic, it can probably be removed by decomposition through

aeration to enhance biological activity. When sand filters are constructed, it is a good idea to
provide a means for introducing air into the lower portion of the filter, either through the drain or
by a buried pipe loop, typically drip irrigation tubing located at the base of the sand. It has been
found that if a sand filter starts to clog, a few hours to a few days of aeration with a small
compressor will provide the added bacterial activity necessary to decompose the clog and bring
the sand filter back to near original performance. Clogging should always be investigated to
determine the reason for the clogging and steps should be taken to eliminate the cause.
Distribution laterals should be installed with access to the end of every lateral so that laterals can
be opened for flushing. Solids tend to accumulate at the ends of distribution lines, and if they are
allowed to remain for long periods of time, the accumulated solids will build at the end of the
pipe and eventually begin to plug the end orifices of the system. Periodic flushing at
approximately six-month to one-year intervals will prevent this occurrence. Normally a provision
is made to flush the accumulated solids into the stone around the distribution system where it
will dry and decompose.
Maintenance should also include obtaining a sample of the sand filter effluent and having it
analyzed for BOD5, suspended solids, ammonia, nitrate, and any other constituents of concern at
the particular location. BOD5 or suspended solid levels greater than 10 mg/L or ammonia levels
greater than 2 mg/L would be an indication of less than nominal performance. With experience, a
maintenance person can often look at and smell a sample to determine if the sand filter is
performing in a normal fashion. Therefore with experience, it is not always necessary to analyze
samples in the lab after every inspection visit if all aspects of the system look normal.
Inspections should also include checking on the current draw of pumps, the performance of
floats and timers in the control system, and the condition of the effluent filter. Sand filter
maintenance should be performed by someone thoroughly familiar with sand filters and their
operation. This will normally be someone other than the health department or the local regulator,
and homeowners should anticipate a nominal fee for this service to be part of the ongoing
operating cost of owning a sand filter. The area over the top of the sand filter should be always
left undisturbed and untrafficked. There should not be normal walking paths over the sand filter
or any use of the area over the filter for storage, construction, or any use or covering that would
prevent free air movement into the sand filter.
Stratified sand filters: Stratified sand filters are generally single pass sand filters that contain at
least two layers of sand media having different grain size characteristics. A layer of coarser sand
is usually placed over a layer of finer sand. With this configuration, somewhat higher loading
rates, either hydraulic or organic, are possible. The coarser sand will filter most of the solids and
provide good air penetration for decomposition while the finer media, like that typically used in a
single pass sand filter, will finish the treatment process.
Bottomless sand filters: A bottomless sand filter is an extra deep (and usually extra wide) trench
that is backfilled with a layer of sand before placing the pressure distribution pipe in a stone
layer under the soil surface. Bottomless sand filters or in-trench sand filters are utilized where
suitable soils for wastewater disposal underlay a slowly permeable soil that is considered
unsuitable for wastewater disposal.

Recirculating sand filters: Recirculating sand filters (RSFs) are typically used for wastewater
flows larger than an individual home. They may also be applicable where space limits the size of
the filter that can be installed for a home or where enhanced nitrogen removal is desired.
Recirculating sand filters get their name from the fact that septic tank effluent is mixed with
water that has been through the sand filter and is cycled back through several times prior to
discharge, either to a soil absorption system or to disinfection and surface discharge.
Recirculating sand filters require a recirculation tank which contains a blend of water that has
been through the sand filter and septic tank effluent. Contained in the recirculation tank is a
pump operated by a timer which is set to run the pump enough time each day to pump over the
sand filter several times the quantity of wastewater which is being generated. The drainage from
the sand filter is then split so that a portion of it is directed back to the recirculation tank and a
portion, to final disposal. Several methods are available for splitting the RSF drainage. First, a
simple float valve can be used within the recirculation tank on a pipe carrying drainage from the
sand filter. If the water level in the tank is high, the valve closes and all the drainage goes
directly to the soil absorption system. When the water level has dropped in the recirculation tank,
the water draining back from the sand filter will flow back into the tank to mix with septic tank
effluent. The mix ratio in the tank is controlled by the amount of time each day that the pump
runs to deliver water over the sand filter, thus determining the amount of time the valve will be
open and drainage from the sand filter recycled. Other flow splitting mechanisms may be used
including a flow division in the bottom of the sand filter so that a fixed portion of the drainage
goes to final disposal and a fixed portion back to the recirculation tank. Flow dividing weirs or
other commercially available flow splitting devices can also be used.
The sand media recommended for recirculating sand filters should have an effective size of 1.2-
2.5 mm and uniformity coefficient of 1.5 - 2.5. Recommended loading rates on a forward flow
basis are 3 - 5gpd/sq ft for domestic strength effluent. Typically a recirculating sand filter for a
three- to four-bedroom home would have a surface area of 100 � 150 sq ft. Smaller recirculating
sand filters have been used successfully in very small yards with careful choice of media and
wastewater application techniques (Pilak, 1994). Because of higher loading rates, recirculating
sand filters must be open to the atmosphere so that good air penetration into the media can be
achieved to assure aerobic treatment. They may have an exposed stone surface with the
distribution pipe embedded just a few inches into the stone, be in a covered container with vents
underneath a wooden cover, or be constructed above grade.
Some designs include a stone layer across the bottom of the recirculating sand filter underneath
the treatment media in the vicinity of the drain just as in a single pass filter. It has been this
author's experience that, with the coarser media of an RSF and a drain that is vented, the
treatment media can be extended to the base of the sand filter without complications.
The wastewater distribution system for the recirculating sand filter may be the same as for a
single pass sand filter. However, spraying the effluent in a cavity or chamber so that the effluent
is more completely distributed over the surface of the sand is a recommended practice
particularly for actual loading rates of 4-5gpd/sq ft.

Table 2 shows typical performance expected for recirculating sand filters for a single family
home.
Recirculating sand filters can be modified to provide enhanced nitrogen removal. One option for
modification was presented by Sandy, et al. (1987) where a stone-filled cavity was provided
underneath the sand filter to serve both as a mix tank and an anaerobic reactor, replacing the
recirculation tank. Septic tank effluent is directed into one end of this zone under the sand filter
and mixes with water that is coming down through the sand filter as it flows across to the other
side where it is pumped either back over the filter or, periodically, to final disposal. The water
coming through the sand filter will have the nitrogen mostly converted to nitrate; and, as the
nitrate mixes with the septic tank effluent, an adequate carbon source is provided to assist in
denitrification. Total nitrogen removal rates as high as 90 percent were reported by Sandy, et al.
(1987).
Another option to enhance nitrogen removal is to simply direct a portion of the nitrified affluent
from the sand filter back to the septic tank to mix with the organic source there to promote
denitrification. Adequate capacity must be provided in the septic tank to prevent the added flow
through the tank from reducing solids removal efficiency. An effluent filter on the septic tank is
highly recommended for this application.
A third option would be to add a separate denitrification tank where either grey water or a
separate carbon source such as ethanol could be mixed with the nitrified sand filter effluent to
promote denitrification. However, unless the denitrified effluent is then passed through another
sand filter or other process to remove BOD5 added by the carbon source, it may cause more soil
absorption system clogging than RSF effluent.
Maintenance of recirculating sand filters: Maintaining recirculating sand filters is about the
same as maintaining single pass filters except that the sand surface and distribution piping of the
system are much more accessible to monitor and/or maintain. Small diameter distribution laterals
need to be flushed to remove solids and prevent orifices from plugging. Monitoring tubes need to
be provided to check for clogging at the surface of the sand treatment media and to check for
possible increases in the saturated zone depth in the bottom of the filter that might indicate
clogging at the drain. Provision for aeration from the bottom up is recommended. This is just a
precaution so that air can be induced if the system does at some time begin to clog or slow down
hydraulically. Leaves and other litter need to be kept off the stone surface so that soil does not
start to build and provide a receptive surface for weed seed germination. Occasionally a weed
seed may germinate and start to grow even on the stone surface and should be removed as soon
as noticed.
The stone surface over a recirculating sand filter can be a landscaping asset. It can be a base for
decorative objects, flower boxes around the edge and shrubs just off the edge. However, most of
the surface area must be left sufficiently open for air penetration into the treatment zone.

Aerobic Treatment Units
Package aerobic treatment units have been used for many years to provide enhanced treatment
and overcome soil and environmental conditions which are not suitable for the use of
conventional septic systems. These units continue to improve, and a number of very reliable
systems are available. The aerobic treatment unit (ATU) industry has worked with the National
Sanitation Foundation in Ann Arbor, MI to develop a testing protocol whereby aerobic treatment
units can be tested and certified to meet a certain level of performance. The testing protocol, NSF
Standard 40 (1996), requires that for a unit to be NSF certified, it must be operated and
monitored by NSF for a period of six months at a facility that they maintain and must meet
established minimum treatment standards.
Aerobic treatment units include pretreatment in a primary settlement chamber which is either a
part of the unit or required as a separate tank. Following the primary treatment chamber,
wastewater flows into the main treatment chamber where aerobic organisms decompose
suspended and dissolved organic substances. The objective of the hardware and tank geometry of
an ATU is to create an environment where microorganisms which are naturally present in the
wastewater will grow and treat the wastewater by consuming the organic matter. This
environment is created by a process of continuously adding air to replenish dissolved oxygen in
the wastewater as it is consumed by the organisms and mixing to provide contact between the
organisms and the wastewater contained substances that are to be consumed. ATUs are also
designed to provide for settling and removal of solids remaining after the aerobic treatment
process. This occurs either in a separate clarifer following the aeration chamber or as a part of
the specific geometry of the aeration chamber itself. Some include a filter to assist the solids
removal process.
For purposes of this paper, data generated during the standardized testings of the National
Sanitation Foundation certified aerobic treatment units are presented to provide a reliable
indication of the potential wastewater treatment results which are achieved when systems are
operating according to the manufacturers' specifications and under a standardized loading
criteria and wastewater strength. The National Sanitation Foundation Standard 40 under which
ATUs are tested requires that the wastewater influent to the test unit have a carbonaceous BOD5
concentration between 100 and 300 mg/L and a total suspended solids concentration between
100 and 350 mg/L. ATUs are tested for a period of 26 consecutive weeks. During the testing and
evaluation period, the system is subjected to 16 weeks of design loading followed by 7.5 weeks
of stress loading simulating four different stress conditions and then a second phase of design
loading for 2.5 weeks. Stress conditions simulated include a wash day stress, working parent
stress, power outage or equipment failure stress and a vacation stress. The inflow regime for the
16 weeks of design loading requires 35 percent of the rated daily hydraulic capacity be added to
the system between 6 and 9 a.m., approximately 25 percent added between 11 a.m. and 2 p.m.
and the remaining 40 percent added between 5 and 8 p.m. to simulate a typical daily loading
from normal activities of a contemporary active family. No routine service or maintenance is
allowed on the system during the data collection time. Additional details regarding the testing
protocol are available from NSF (1996).

Ten manufacturers who are marketing ATUs with NSF certification were contacted for
information on their NSF test results. Seven manufacturers responded and provided their NSF
Standard 40 test results reports. The reports provide detailed data on system performance on a
day to day basis over the approximately 28-week testing period.
Table 3 presents a summary of average values obtained for BOD5, suspended solids,
temperature, dissolved oxygen and, where available, nitrogen removal results. Data from eight
different units representing seven different manufacturers are included in the summary table.
Four of the units are systems which depend upon extended aeration and activated sludge
processes as the treatment mechanism. Each of the other four units reviewed involve a somewhat
different process. They are described respectively as 1) extended aeration activated sludge with
filtration, 2) mechanical aeration with filtration, 3) attached growth aerobic-fixed film anaerobic,
and 4) attached and suspended growth.
Testing for nitrogen removal is an optional extra. None of the extended aeration activated sludge
plants included nitrogen removal data in the report. Of the other four units in the table three were
tested for nitrogen removal. In the activated sludge process, microorganisms remove soluble
contaminants from the wastewater utilizing them as a source of energy for growth and
production of new microbes. The organisms tend to be flocculent in nature and form settleable
clumps that also entrap particulent organic matter. The organic matter are attacked by
extracellular enzymes that solubilize the solids to make them available to the microorganisms as
a food source. The conversion of the organic matter from soluble to biological solids allows for
removal of the organic matter by settling of the biological cells in the treatment process (Grady
and Lim, 1980).
Extended aeration is a modification of the activated sludge process in which microorganisms are
allowed to remain in the treatment process for long periods of time. The large amount of
biological solids in the process provides a buffer for shock loading of organic matter. The long
aeration period allows for the organisms in the system to consume themselves, reducing the total
amount of solids produced by the treatment process (NSF, 1996). The activated sludge process is
referred to as a suspended growth system. Interruption of the aeration process for a long period
of time can have serious impact on the process.
Some of the units are designed to provide an environment for denitrification following the
aerobic treatment system. This process requires the aerated effluent to be subjected to anaerobic
conditions containing an energy source (carbon source) and denitrifying bacteria. These
processes are accomplished in various ways in the various proprietary systems. Table 3 shows
that some systems were able to achieve a high level of total nitrogen reduction.
The day to day data in the test reports generally show very consistent performance with BOD5
and suspended solids usually less than 10 mg/L in the final effluent and often less than 5 mg/L.
Some units showed more response to the stress loadings than others in terms of the occurrence of
elevated BOD5 and suspended solids concentration in the effluent. For a plant to achieve
certification as a product producing class 1 effluent, it must produce an effluent that meets the
EPA guidelines for secondary effluent discharge. The 30-day average BOD5 concentration of
effluent samples must be below 25 mg/L. The seven-day average carbonaceous BOD5

concentration must be less than 40 mg/L. The criteria for total suspended solids are that the 30-
day average must be less than 30 mg/L; and the seven-day average, less than 45 mg/L. The data
for all the plants reviewed showed performance results well below these maximum criteria levels
for class 1 status.
Table 3. Aerobic Treatment Unit Performance Data Obtained During
NSF Testing; Values are Averages over the 28-week Test (all values
mg/L except temperature).
Treatment Extended Aeration Activated Sludge Extended Attached
Film
Growth
Type
air
Mechanical Annaer.
activated
Aeration
sludge
Filtration
w/filter
BOD5

Influent 173 184 148
176
146 143 159
144
Effluent 6 10 141
7 6 13 5 9
Susp.

Solids
Influent 189 209 193
213
195 215 182
197
Effluent 7 9 481
14 6 17 5 7
Avg.

Temp. (�
C)
Influent 17 18 12 17 12

13 12
Chamber 16 17 10 18 13 16
Effluent 16 17 10 14 11

11 11
Dissolved

O2
Chamber 1.4 5.0 5.7 8.0

8.9
2.1
Effluent 3.1 2.2 3.0 7.1

6.4

3.7
Nitrogen

Ammonia
Influent

22

Effluent

1.8

Treatment Extended Aeration Activated Sludge Extended Attached
Film
Growth
Type
air
Mechanical Annaer.
activated
Aeration
sludge
Filtration
w/filter
Nitrate

Influent

0.5

Effluent

15

Total N

Influent

33.5

Effluent

19.9

1High effluent BOD5 and S.S. values were caused by 4 consecutive days of high output values. If these 4 days are
omitted, avg. BOD5 is 6 mg/L and avg. S.S. is 8 mg/L.
The test data show ATU effluent quality in the same range as sand filter effluent. Converse and
Tyler (1994) showed that ATU effluent discharged to a failing septic soil absorption system has
the capacity to result in renovation of the clogging and subsequent reliable performance.
Maintaining Aerobic Treatment Units: Just as with other secondary treatment processes,
regular monitoring and maintenance of ATUs is required to assure that the units continue to
provide a high level of treatment and good effluent quality. Manufacturers literature provides
recommendations on service intervals and components to be checked. Recommendation are
provided to help users understand what is and is not appropriate to be flushed into the system.
Owners are cautioned to be alert for change in the sound of system operation or system odor that
may be early indications of a need for service. Service intervals are specified for checkups by a
qualified service provider.

Waterloo Biofilter
Jowett (1995), reported on the development of the Waterloo Biofilter which is a device using
open cell urethane foam similar to the material used in the trickling filter in a configuration very
much like a recirculating sand filter. For a home this system can be housed in an above grade
structure of about 32 - 36 sq. ft in floor area or below grade in a septic tank. Septic tank effluent
is pumped over the synthetic media in small bursts and the effluent from the media is partially
circulated back to the septic tank or a pump chamber and partially discharged to a soil absorption
system or other final discharge receptor. Mechanical air circulation within the biofilter container
is required in order to achieve nitrification levels similar to those achieved with a sand filter. The
Waterloo biofilter is a proprietary system that is being marketed in Ontario having been
approved by the Ontario Ministry of Environment (Jowett, 1996).

Other Systems: Numerous other systems are being utilized to provide secondary treatment in
onsite and small decentralized wastewater treatment settings. Most have not yet been a subject of
detailed published information. Technologies such as upflow filters, peat filters, geotextile
filters, expanded aggregate sand filters, and other systems are being utilized and have been
reported to provide treatment results comparable to the secondary treatment concepts discussed
here. These also appear to be very promising technologies for the future.

Expectations and Needs
The potential for enhanced use of existing secondary treatment technologies and development of
other similar technologies for onsite and small decentralized wastewater treatment systems is
promising. With reliable equipment readily available--including pumps, controls, automatic
valves and various plumbing schemes easily fabricated with plastic pipe--the options are many.
Small-scale secondary treatment processes have proven that final effluent quality rivaling that of
large municipal wastewater treatment plants is achievable. These systems provide the
opportunity to utilize slowly permeable soils for completing the wastewater treatment process or
may be approved for surface discharge following disinfection where appropriate. Many soil
conditions not currently approved for septic effluent disposal have the capability of reliably
removing nutrients and completing the pathogen removal process so that protection of public
health can be assured and environmental degradation virtually eliminated.
One issue remains to be solved for certain sites adjacent to sensitive inland waters where
phosphorous is the major issue of concern. None of these systems have been shown to reliably
remove phosphorous to levels required for discharge around sensitive inland lakes and streams.
However, this issue is currently being addressed by researchers in several parts of the world.
Reliable secondary treatment with regular maintenance programs will provide very long term
continuing high quality treatment and environmental protection without the need to expand
expensive central collection and treatment facilities. Proper use of this technology also can
provide a tool for local zoning administrators to plan and control development rather than letting
it sprawl over the countryside with allowable development sites dictated only by the most
permeable soil conditions. Utilizing secondary treatment to remove the potential for wastewater
to clog soils provides the opportunity to utilize soils that have long been passed over as
undevelopable until the sewers arrive. It is important for practitioners in all sectors of the
wastewater treatment community to become familiar with these technologies and trained on their
proper use. It is imperative that maintenance organizations develop to take care of these systems
so that they can provide long- term, effective treatment for the owners.

References
Converse, J. C. and E. J. Tyler. 1994. Renovating failing septic tanks--soil absorption systems
using aerated pretreated effluent. In: Onsite Wastewater Treatment Proceedings of the 7th
International Symposium on Individual and Small Community Systems, pp. 416-423. American
Society of Agricultural Engineers, St Joseph MI 49085.

Grady, Jr., C. P. and H. C. Lim. 1980. Biological wastewater treatment: theory and applications.
Marcel Decker publishers, New York.
Jowett, E. C. and M. L. McMaster. 1995. Onsite wastewater treatment using unsaturated
absorbent biofilters. Journal of Environmental Quality. 24:86-95.
Jowett, E.C. 1996. Personal communication.
Loudon, T. L. and G. L. Bernie. 1991. Performance of trenches receiving sand filter effluent in
slowly permeable soils. In: Onsite Wastewater Treatment, Proceedings of the 6th National
Symposium on Individual and Small Community Systems, pp. 313-323. American Society of
Agricultural Engineers, St Joseph, MI 49085.
Metcalf and Eddy, Inc. 1991. Wastewater engineering: treatment disposal and reuse. Revised by
G. Tchodanoglous and F. C. Burton, pp. 1035-1037.
NSF International Standards 40. 1996. Residential wastewater treatment systems. NSF
International, Ann Arbor MI 48113.
Sandy, A. T., W. A. Sack and S. P. Dix. 1987. Enhanced nitrogen removal using a modified
recirculating sand filter (RSF2), In: Onsite Wastewater Treatment, Proceedings of the 5th
National Symposium on Individual and Small Community Systems, pp. 161-170. American
Society of Agricultural Engineers, St Joseph MI 49085.
Siegrist, R. L. 1987. Soil clogging during soil surface wastewater infiltration as affected by
effluent composition and loading rate. Journal of Environment Quality, 16: 181-87.
Tyler, E. J .and J. C. Converse. 1995. Soil acceptance of wastewater affected by wastewater
quality. In: 8th Northwest Onsite Wastewater Treatment short course, pp. 96-109. Seattle.
ATU manufacturers who provided data:
Aquarobic International
Bio-Microbics, Inc.
Clearstream Wastewater Systems, Inc.
Clearwater Ecological Systems, Inc.
Delta Environmental Products, Inc.
Hydro-Action, Inc.
Norweco, Inc.
1 Professor and Extension Agricultural Engineer, Michigan State University; President-elect, National Onsite Wastewater Recycling
Association (NOWRA)

Affordable Household Systems for Community Sanitation
Stephen Hodges
Construction Resource and Development Centre, 11 Lady Musgrave Avenue, Kingston 10, Jamaica
Tel: (876) 978-4061, Fax: (876) 978-4062, Email: crdc@jol.com.jm

I would like to speak about my experiences with Community Sanitation in two squatter
upgrading sites in Montego Bay, Roseheights and Norwood over the period 1995 until the end of
last year. Before that time, neither myself nor Construction Resource and Development Centre,
the NGO I worked with, had particular experience with community sanitation and its attributes.
Nearly three years later, I hope to be able to point to where, given our circumstances, we feel we
should go next. Along the way, I will try to draw out the issues to do with the household systems
I felt we, myself and the Sanitation Support Unit of CRDC learnt about.
The site was all limestone hills, where several pre-project activities had occurred. Bore holes had
been done, an assessment of the environmental impact of the proposed upgrading works,
particularly the putting in of roads and water, and a survey of all the lots to see what types of
disposal facilities they had, and some measure of the household's preferences.
A mix of latrines and water bourne solutions were in place, many not discharging into an
acceptable place, and 19% had no sanitation solution whatever. The use of "Lada bags" as a
disposal technique gets less and less acceptable for neighbors as the density of a settlement rises.
There had also been an attempt to set design standards for sanitation systems for the site, which
had built six demonstrations VIDP's along with a greywater disposal system. As a follow up to
this attempt, the SSU had as one of its first tasks the countering of the rumour that they had come
to impose VIDP's on the community. The resistance to the VIDP's was surprising, as the
demonstration units had been well received. We can only presume that this was because of a
particular attribute of a VIDP in Jamaica, that they are free. We do not know of one VIDP that
has been paid for by its user, and this rather skews how they are accepted. Indeed, communities
from all over the island who need help with sanitation now ask funders for VIDP's, even where
this is not the optimum solution. The fact that the SSU was not offering anything free, but had a
credit programme to allow the householders to acquire a facility if they needed one, gave, we
feel, a much more accurate measure of the acceptability of the menu available.
SSU set out to develop a menu of solutions that would fit the site conditions as well as the ability
to repay the loans available. This included single ventilated latrines, composting toilets, VIDP's,
absorption pits as well as septic tanks and tile fields or soakaways, and discussions were held
about the possibility of condominial septic tank systems for groups of houses on difficult sites.
The menu rapidly shrunk to a single item, the absorption pit, providing for a flush toilet (a supply
of low cost, low flush WC's was brokered through a hardware store). The community was
obviously looking up, they were likely to own the lot they were living on after the upgrade, and
they knew what they wanted. There has never been much of a niche for intermediate technology
in Jamaica, probably because it is too easy to set ones standards by relatives up north, or at least

from "Days of Our Lives". Practically, one can hardly blame them, as water was coming into the
community, and a pit would cost around the same as a VIDP.
From other experience, VIDP's come with a second drawback in Jamaica, in that they are new
technology, and there is no culture of emptying latrines. Three years after building VIDP's one
has the task of education of the owners on how to deal with the waste, as one cannot effectively
teach this when they are new and empty.
Somewhat to the amazement of our technical backup from the Environmental Health Project, as
well as some of the officials from the Ministry of Health, we found soil or marl or fine granular
material on almost all of the lots we worked with. As we knew of the number of sinkholes that
were in use for sewage disposal, we had assumed that we would not be able to dig a hole without
finding solution hollows. In reality, the holes, where we did find them, were obvious, and could
be sealed up. It became one of the tasks of the SSU technical officers to inspect the pits that were
dug to look for any evidence of solution hollows. Technical advice was sought from several of
the government agencies to set the standards for the pits, ending up with simple rules for distance
to solid rock. Percolation tests were organised in the bottom of pits in new areas, to stay within
code. Despite an approach that sought agreement from wide ranging technical expertise and
officialdom, the SSU gets criticized to this day for not "sealing the pits", which in a water bourne
system, would not have helped anyone.
The rest of the SSU approach drew less criticism, and indeed a lot of praise. The team set up a
service oriented unit which saw the householders somewhat as clients, and charged up to 7.5% of
the loan amount for a range of services, including inspection, design, siting, arrangement of a
contractor, site inspections, payment services connected to the loan, acquiring a list of materials
from the hardware to assist in completion of a bathroom structure and final inspection by the
Public Health Inspector. In addition, the unit ran a public education programme, working with
the community on their problems, trained and supported a team of community animators who
continued in the community when SSU moved on, and monitored several indicators of public
health significance. Because of some disposal problems, the SSU is now working on greywater
disposal issues in the community, and trying to produce some training materials.
Having more than satisfied the numbers targeted, achieved near full cost recovery and put aside a
useful amount as a sustainability fund, CRDC has kept the SSU open to look for work in
community sanitation.
I should at this point make a plea for credit to be available for sanitation purposes. The SSU
proved that a unit can make good use of credit in doing sanitation work, particularly in achieving
cost recovery while producing substantial numbers of acceptable solutions.
CRDC is hoping to interest some of the government agencies in assisting with credit so that the
collaboration that was achieved in the Montego Bay project can be continued to the many other
communities needing help. We have started a project, ACES (Advancing Cooperation in
Environment and Sanitation) to assist with the training, information, designs, advocacy and

persuasion needed to get other agencies active in the sanitation field, and to bring in some
organisations who should be active.
That leaves me to deal with some left over technical questions. Can anyone give a judgement on
how much nutrient load comes from VIDP's when they are emptied and spread on plants, vs.
absorption pits and septic tanks. Is the only solution to collect and treat, apart from no one living
on the land? We felt particularly exposed having to make compromises, take decisions with the
community as a partner, with little data to back us up. Is it really impossible to have a water seal
and be environmentally friendly?

PART 2

COUNTRY REPORTS

Regional Workshop on Application of Environmentally Sound
Technologies for Domestic and Industrial Waste Water Treatment
David A. Matthery DPH, CPA, BSc (UWA)
Senior Public Health Inspector, Ministry of Health and Civil Service Affairs, Antigua, 1998

Introduction
The disposal of raw sewerage into freshwater and the marine environment will inevitably
threaten the public health of any country. The growing standard of living and increased
industrialization, including tourism, has resulted in more and more wastewater to be disposed of.
Antigua and Barbuda have no central sewer system. However, several types of individual
systems are used. Notably, the Bucket system (night soil system) Pit Privy, the Septic Tank
and Soak-a-way and the new Sewerage Packaging Plants.
The twin island state of Antigua/Barbuda suffers severely from droughts. Within the last ten
years the annual rainfall was some meager 36-42 inches per year. With a thriving and expanding
tourism industry and a daily water consumption rate of 3.8 million gallons per day, means that an
alternative source of water is needed to supplement the scarcity of rainfall. Thus, to meet the
daily demand rate seawater is desalinized. Wastewater in Antigua/Barbuda is mainly generated
form septic tanks systems, sewage plants and to a lesser extent some small industries such as
paint production, distillery and brewery. The potential threat of marine pollution from sewage
contamination has far reaching implications for public health.

Sources of Pollution
Bucket System � The Central Board of Health a division in the Ministry of Health presently
operates this system for a very small percentage of the population. Human excrements are stored
in pails/buckets and are collected from the residents during the period of 10.00 p.m. to 5.00 a.m.
The waste is transported to the dumpsite where it is buried in shallow trenches two feet deep.
There are 220 residents using this system, which from time to time experience some difficulties
in its regular and efficient management. Thus, illegal collection and disposal methods, result in
raw excrement being disposed on in the marine environment and open drainage.
Septic Tanks � This system is used by approximately 65% of the resident and commercial sector
in the country. Within the city of St. John's the predominant soil structure is clay and land space
for building construction (residential and commercial) is very limited. This situation has caused
the average septic tank to be undersized in relation to the number of bedrooms/bathrooms. Also,
very little attention is being paid to the permeability of the soil. As a result of this action there
has been a proliferation of effluent flowing from one building to the next, creating several
wastewater nuisances in the country. To alleviate some of these nuisances the wastewater is
channeled to the street drains en route to the sea.

Packaging Plants � The result of a survey conducted by the Caribbean Environmental Institute
(CEHI) and the Pan American Health Organisation (PAHO) in 1992 revealed that 88% of the
sewage packaging plants operate below standard. Further, the result notes that 12% of the plants
operate good. 35% operate moderately, 24% operate poor and 24% of the remaining plants are
not operational.
The effluent at 12 of the plants are chlorinated before disposal. At few of the plants chlorine
tablets are placed in the clarifier overflow to disinfect the effluent, this is a very ineffective
means of disinfection. The effluent from these plants are disposed of directly into the marine
environment, salt water lagoons, and into street drains. In some instances it is recycled for
irrigation.

Implications for Public Health
There are several bacterial, viral, rickettsial and helminthis communicable diseases that are
transmittably by environmental agents and vectors, which has the potential to sustained in
humans by the pathogens that live in the excreta of an infected person, and find their way by
water, food or soil to another human being. "The continued careless handling of human excreta
maintain these diseases". Septic tank system has the potential to achieve hygenic objectives
admirably, and it is easier to keep clean and free of odour, when compared to the pit privy. The
controversy with the septic tank system in Antigua/Barbuda is not their hygienic failure, but their
failure as a disposal process, squeezed into small lots in soil of limited permeability.
In St. John's effluent from septic tanks are discharged either directly, or through a seepage pit, to
street gutters and other open drainage. This effluent at best, has only received primary treatment.
Gray water from bathing, laundry, sink etc., usually is piped directly into the gutters and open
drainage en route to the bay.
Typhoid and infant gastroenteritis are two disease indicators of unsanitary sewage/excreta
disposal problems. According to a 1985 PAHO workshop report, 60% of the annual
gastroenteritis cases are reported from the St. John's population, where unsanitary sewage
systems are found.

Institutional Framework
The Central Board of Health (CBH) in conjunction with the Development Control Authority
(DCA) have been reviewing all plans for new developments in the island. With the past five
years a total of 4,194 plans have been reviewed and pass. The following percolation rates (table
1) are being used based on the soil type.

Table 1. Percolation rates for Antigua/Barbuda
Type of soil
Rate per minute/inch
Clay Over
60
min/in
Volcanic 25
min/in
Topsoil 20
min/in
Marl 18
min/in
Loam 14
min/in
Limestone 13
min/in
Topsoil/Clay 35
min/in
Topsoil/loam 34
min/in
Topsoil/Marl 10
min/in
The size of the septic tank is calculated based on the number of bedrooms and an average of 30
gal./per person/per day usage of water, when only wastewater from the toilet is going to the
septic tank. When all wastewater are to be disposed of into the septic tank then the criteria is
calculated using a minimum of 60 gal/per person/per day (Table 2).

Table 2.
Toilet water only All waste water combined
30 gal./per
person/per day
60 gal./per son/per day
# of Bedrooms
Vol.gal Liq. D Ext. L
Ext.
Vol.gal Liq. D Ext. L
Ext. W
W
*2
720
4'
10'�0" 3'-10"
720
4'
10'-0"
3'-10"
*3
720
4'
10'�0" 3'-10"
1080
4'-6"
12'-0"
4'-0"
*4
720
4'
10'�0" 3'-10"
1440
5'-0"
12'-3"
4'-6"
5
900
4'
11'-0"
4'-2"
1800
5'-0"
13'-6"
5'-0"
6
1080
4'-6"
12'-0"
4'-0"
2160
5'-0"
14'-7"
5'-4"
7
1260
4'-6"
12'-6"
4'-6"
2520
5'-0"
15'-8"
5'-8"
8
1440
5'-0"
12'-3"
4'-6"
2880
5'-0"
16'-7"
6'-0"
* the minimum capacity for any septic tank in Antigua/Barbuda is seven hundred and twenty gallons.

Monitoring of the environment
The CBH department of the ministry of Health has been monitoring the near shore environment
to ascertain its status from since 1989 in conjunction with the Caribbean environmental Heath
Institute. The feacal coliform, feacal streptococcus ratio is been used as indicators of the level of
pollution. Four categories are used;
(1) FC:FS>4
- Pollution from human wastes
(2) FC:FS<0.7
- Pollution from livestock or poultry
(3) FC:FS 2 to 4 - Mixed pollution but mainly human
(4) FC:FS 0.7 to 1 - Mixed pollution but mainly livestock or poultry
The samples generally falls into category 2 which denotes that the pollution present are of
livestock or poultry. The areas mainly monitored are recreational beaches.
The majority of the hotels and some business places employ the use of sewage packaging plants
on the islands to date there are 34 such plants. A survey in 1994 by PAHO revealed that 88% of
these plants are not functioning properly, that is effluent with a BOD of 30 mg/l and SS of 30
mg/l.

Environmentally Sound Technology
When one focuses on a new technology and seek to determine whether or not such technology is
appropriate or environmentally sound for their situation a number of variables must be taken into
consideration, such as;
Functionality and process performance
Sustainability
Cost and affordability
Functionality and process performance relates to the ability of the technology to improve public
health and environmental conditions under the existing conditions. The technology must have the
ability to remove the present pollutants and assuring safe disposal of the liquid and solid output.
The sustainability criteria of the new technology must ensure the potential exist for continuous
operation of the facility in the future.
The final point I want to mention here is the notion of cost and affordability, before the
implementation of any new technology we must ascertain whether or not it is cost effective when
compared to another technology.

References
Caribbean Conservation Association
The Island Resources Foundation, Environmental Agenda for the 1990's, Sept. 1991.

Antigua and Barbuda Environmental Profile, April 1991.

CIBA-GEIGY Corporation
Caribbean Desalination, A technical operational seminar, Aruba 1991

CEHI/PAHO
Assessment of Operational Status of WasteWater Treatment plants in the Caribbean, December
1992

Chanlett, Emil T., Environmental Protection, McGraw-Hill Book Company, 2nd edition, 1979

Chemistry and Food Technology
Dunbar Scientifica, Ministry of Agriculture, Fisheries, Lands and Housing., Dunbars, Antigua,
Vol 2, No 1, 1991.
Davis, Mackenzie L./David A. Cornwell, Introduction to Environmental Engineering, McGraw-
Hill series, 2nd edition, 1991
1. Freedman, Ben., Sanitarian Handbook, Theory and Administrative Practice for
Environmental Health, Peerless Publishing Co., 4th edition, 1977.
2. PAHO/WHO, Workshop on the Operation and Maintenance Waste Water Treatment
Plants, Antigua., Aerobic Biological Systems, 15-18 November 1994.
3. Salvato, Joseph A., Environmental Engineering and Sanitation, Wiley-Interscience
Publication, 1982.
4. Wagner, E.G. and J.N. Lanoix, Exreta Disposal for Rural Areas and Small Communities,
WHO Geneva, 1958.

An Integral Approach to Wastewater Management is a Necessity Than a
Choice For Small Islands
(A View From a Policy Maker)
Dr. Ing. Elton L. Lioe-A-Tjam
Directorate VROM, Government of Aruba, Wayaca 31-C, Oranjestad, ARUBA
Tel: 297-832345, Fax: 297-832342, Email: vromaua.dir@setarnet.aw

Paper prepared for UNEP-CAR/RCU workshop on
Adopting, applying and operating environmentally sound technologies for domestic and industrial
wastewater, November 1998, Montego Bay, Jamaica.

Drs. Ing. Elton L. Lioe-A-Tjam
Director of the directorate of VROM,
Ministry of Justice and Public Works
Adjunct professor of MAPTS,
University of Anchorage Alaska.

Introduction
The concerns for untreated wastewater dates back to the Roman empire were sewer lines to some
extent were separated from drinking water. Much later in Paris the need of sewer lines was
severely felt as a result of urbanization. The increased population brought along more unhygienic
events and sicknesses. Paris was forced to implement the first `modern' sewer line system in the
world. Many other cities followed. The implementation of sewer lines meant the direct solution
to the hygienic aspects in the direct surroundings of the cities, but it didn't solve the problem as
the wastewater was discharged `further down the line'.
The discharge of raw water is in fact not a problem if the receiving waterbody is `capable'
enough to handle the discharge. This means that the natural biological purifying capacity
(buffering capacity) is capable of dealing with the `foreign substance that is been put in the
waterbody.
Wastewater treatment has evolved in three phases.
Phase 1: Hygienic aspects. In this phase the accent was laid on the removal and treatment of
rough, floating fecali that poses a threat to human health. Treatment plants were
designed to treat raw water;

Phase 2: Environmental aspects. In this phase environmental concerns were added. An example
is the measures to reduce nutrification of waterbodies as a result of treatment plants
effluent discharges;

Phase 3: Effects aspects. The accent shifted in this phase to the toxicity of effluent discharges
(enriched or not with precipitation chemicals) on organisms.

The objective of this paper is not to discuss the technical aspects of wastewater treatment, but it
deals with the management aspects that are often considered as a separate process. This paper
will discuss the issues that small islands have with wastewater management and the necessity of
an integral approach.

Urbanization
The last two decades the economies of most Caribbean islands have grown primarily because of
the shift or introduction of tourism. This however didn't change the overall economic structure.
Most of the islands remain a `single economic pillar' economy with little diversification. This
simple economic structure has given many of these islands a higher standard of living.
Associated with economic growth comes also:
� an increase in population;
� an increase of foreign visitors;
� an increase of land use;
� an increase of waste (solid as liquid).
Caribbean islands economic developments can be divided in:
1. `classical';
2. `modern'.

Ad 1. These types of developments has an historical background i.e. `cities' were formed
around the economic center's.
Ad 2. These types of developments are been established `scattered' over the landscape e.g.
tourism developments.
Both developments have the function of `pull-factor's, which means that settlements (residential
and/or commercial) will be developed in the vicinity of these developments. The result of this is
the forming of a wider area network of settlements. Besides this `network effect', developments
also induce a stronger income stratification. This stratification is translated in `urban sprawl'.

Water
The majority of the Caribbean islands use ground or surface water as potable water. Surface
water also has other functions in the rural area e.g. the washing of clothes in rivers and streams
transport. The replenishing of these waterbodies is solely dependent on rainfall.

An ever increasing amount of users (resident or alien) means:
� higher land claims;
� conflicting functions;
� higher water usage;
� depletion of waterbodies.
Many of the new developments can be located above an aquifer or alongside a river or stagnant
waterbody, with the possibilities that the waterbody can be contaminated or depleted.
The use of water will eventually result in the discharge of raw water. This discharge can be done
by surface run-off, infiltration or direct discharge in the waterbody. Water will always seek the
lowest point of energy and will accumulate at this level. If raw water is discharged by the first
two ways, the travelling time and filtration through these mediums will reduce the `load' to the
receiving waterbody. However these types of discharges has hygienically implications attached
depending on the load and the method used. Time, purifying capacity and `loads' determines the
function of the waterbody.
Many waterbodies on some islands have multiple functions. Water management is required.

Infrastructure
Wastewater treatment is a very costly business giving the fact that sewer lines and plants has to
be installed to reduce environmental problems. The costs varies depending on:
� the type, method of and amount of lines;
� the treatment plant design.
Urban sprawl and scattered planning have led to large surface areas in which sewer lines and
plants has to be developed. This aspect is one of the major factors in the costs in implementing
waste management policies.
In addition depending on the landuse policy, often the required land is not owned by
government, which will lead to higher cost.
The aspect of plant design is crucial. The design of the plant not only determines the amount of
land that is required, but also the maintenance and skilled labor. A complex plant requires high
maintenance and qualified labor to operate the plant. A lack of any of these to components will
eventually lead to a not optimum functioning plant (technology management).

Case: Wastewater treatment in Aruba
Island description
� Population: ca. 93.000 inh.;
� Visitors: ca. 750.000/a;
� Households: ca. 26.000;
� Hotel rooms: ca. 7000
� Surface: 181 km2.
Current wastewater situation
� Desalinated water is used for all uses e.g. washing etc. Water consumption is 170 l per
person per day;
� Most of the produced wastewater is been discharged into septic tanks (decentralized
collection). A part of this is being used for irrigation purposes, the rest infiltrates into the
ground;
� 26% is collected and transported to the treatment plant;
� 6% of the household wastewater is discharged untreated directly into the sea;
� by heavy rainfall the surplus is discharged into the sea;
� thermal process cooling water is discharged daily into the sea by the utility company
(36.000 m3) and the oil refinery (60.000 m3);
� two treatment plants (35.000 i.e. and 15.000 i.e.). Plant types are activated sludge with
UV-treatment and compactor system.
Current bottlenecks
� the majority of the existing sewerlines has exceeded its technical lifespan. It can be
assumed that all of these lines must be replaced.
� insufficient pumping capacity;
� limestone underground;
� mixed sewer line system i.e. rain and raw wastewater in one sewer line system.
Initiated activities
� Inventarisation of current system;
� Master plan design `Afvalwaterstructuurplan Aruba 1997-2010';
� Drafting of the necessary legislation;
� Integration of various policy plans e.g. National Environmental Policy Plan 2000-2005
(draft);
� Designing of automated monitoring systems and parameters.

Proposed Effluent Quality Standards
Parameter
Unit
Nature site
Irrigation site
Sea
BOD
mg/l
<20
<20
<20
Ntot
mg/l
10
--
--
Ptot
mg/l
<3,0
--
--
TSS
mg/l
15
<50
<15
E.coli
n/100 ml
103- 105
<102
103- 105

An Integral Approach
Implementing wastewater management policies implies a `total chain management'. This means
looking at issues at the source and at the discharge, integrating other disciplines than only
looking at the technological side. Examples of the other disciplines that directly is related to
wastewater management are:
1. planning;
2. legal;
3. social.
Ad 1. the location of the treatment plant is dependent on landuse, the zoning functions and
regulations and the existing facilities e.g. landfills. Here is where physical planning plays
a crucial role.
Ad 2. proper and adequate legislation is necessary to provide the legal framework that is
required.
Ad 3. involvement of the community is essential to prevent `myth's' and to stimulate other
related programs associated with the treatment facility e.g. water consumption reduction
programs.
In basic the procedures that must be followed in implementing an integral management system
are:
1. typifying sources i.e. diffuse or point;
2. designing policies i.e. master planning;
3. drafting legislation;
4. development of support decision tools;
5. implementing and monitoring.

Conclusions
� Most islands depend on tourism. The dilemma is that many of the related issues is a result
of the development of the industry on the islands, but the bottom line is that a bad or
faulty wastewater management will also be the end of this economic activity.
� The involvement of the different stakeholders is essentials given the fact that the costs are
very high and must be shared, as most Governments don't have the required resources.
An approach to the latter is that solutions should be sought in technologies that can be
managed by local authorities that meet the environmental standards.
� Integration with physical planning is crucial and must be synchronized.

Wastewater Treatment and Disposal in the Bahamas
Christal Francis
Water & Sewerage Corporation, PO Box N-3905, Nassau, BAHAMAS
Tel: 242-323-7474 ext. 5738, Fax: 242-322-5080

Introduction
The Water and Sewerage Corporation is a quasi government organisation established under the
Water and Sewerage Corporation Act (1976) with responsible for the provision of water and
sewerage services in the Bahamas. The present scope of it activities encompasses water and
sewerage service in New Providence and water services in several of the more populated Family
Islands.
Throughout the country, the principal method of wastewater collection and disposal systems are
septic tanks and pit latrines systems (90%) and the remaining ten percent (10%) are on a
centralised sewerage collection systems, which including the islands of Grand Bahama and
Abaco.
In New Providence approximately sixty-five percent (65%) of the total population resides on the
island and only fifteen percent (15%) of the households are on a centralised collection system
and the remainder on septic tank and pit latrines. The table below gives a summary of the
number of service connections and the rate of growth in the sector.
DESCRIPTION
ANNUAL COMPARISON OF TOTAL WATER AND SEWAGE
CONNECTIONS FOR KEY YEARS IN NEW PROVIDENCE

Units
1977
1980
1985
1990
1996
Sewage Connections
no. 2,720 2,842 3,131 5,008 n.a.
Water Connections
no. 22,300 23,188 26,430 28,645 n.a.
Generally, sewerage installations are conventional gravity sewer conduits in bedded trenches
which run through the centre of roadways with manholes at intervals not exceeding four hundred
feet (400 ft.). The sewer lines are constructed of concrete, vitrified clay and PVC pipes ranging
in size from 4" to 21" in diameter. All pumping or lift stations are standardised with Flygt
submersible pumps and equipment.

Plant Operations
There are six (6) main independent drainage areas in which treatment processes range from
primary to secondary treatment. The six areas and the type of treatment are listed below.

Malcom Park
-

Primary
treatment
Yellow Elder Gardens

-
Secondary
Eastern District � Fox Hill
-
Secondary
Pinewood Gardens

-
Secondary but not operational
Flamingo Gardens

-
Secondary but not operational
Nassau International Airport
-
Secondary but privately owned
All centralised wastewater collected is predominantly domestic in nature with an average
influent concentration of 200 mg/l BOD5 and suspended solids. The efficiency of the treatment
process is to conform to the national standard of 35 mg/l BOD5 and 30 mg/l suspended solids for
disposal. Also, the final effluent is to be chlorinated to a minimum of 0.5 ppm. Final effluent
disposal embraces deep well injection into wells cased to salt water (which range in depth from
250 ft. to 740ft.), or controlled recharge/recycling via drain field, lagoon or sand filter
techniques. While there is no practice of wastewater disposal into surface water bodies, provision
for the employment of tertiary treatment against any water contamination can be permitted on a
case and facility design/performance certification basis.
All sludge from a treatment process is dried via sludge drying beds and later land filled. There is
a centralised septage receiving site with both anaerobic and facultative lagoons from which the
final effluent is discharged into a 250 feet deep disposal well. This lagoon system is fairly new to
the Bahamas having been commissioned in June 1996. Since that time, the lagoons have not
been desludged to-date.
From the perspective of wastewater fate and ultimate environmental implications, the
Department of Environmental Health Services (DEHS) is the foremost regulatory agency
governing the provision and performance of treatment facilities within the country. The
Department has responsibility and authority to spontaneously monitor all facilities, and to act as
an enforcement agent for the Water and Sewerage Corporation.

National Sewerage Development
To efficiently accomplish the task of sewage development, the government's policy for
infrastructure development is enunciated in its Manifesto, which advocates environmental
conservation and preservation through adequate wastes management, including expanded
sewerage collection and treatment facilities. The specific requirements governing the need for
sewerage collection and treatment facilities are outlined in the Bahamas Building Code and
emanating policy for subdivisions. The Building Code requires a treatment plant installation at
developments with a wastewater flow greater than 6,00 US gallons per day, which prompted the
twenty-four (24) lot subdivision policy requiring developers to install a sewerage collection and
treatment plant system.

All engineering designs of the systems, including lift stations, and material selection, are to be
approved by the Water and Sewerage Corporation. All designs in part are based on an average
daily flor of 50/gal/person/day. The subdivision and design policies are to foster and facilitate the
provision of water and sewerage facilities to new subdivisions and private developments, which
will be standardised and compatible with the public collection, treatment and disposal system
both present and in future.
When private developer's complete the installation of the infrastructure, the WSC ensures that
sewers are lamp tested to ensure alignment and infiltration to confirm the existence of proper
gradient and pipe jointing of all individual property connection risers. It should also be noted that
where there is an existing collection system, properties under new construction within 600 feet of
the system are legally bound to connect to the system.
The above named practices and requirements are expected to ensure that as the rate of
developments progress there would be a significant reduction of septic tanks which would also
retard the rate of groundwater pollution.

Sewage Treatment and Residual Management
Despite the method of wastewater treatment utilised, the management of its residual is of utmost
importance. The most common method of treatment employed in the country is secondary
treatment utilising the extended aeration process with sludge treatment via sludges drying beds.
Dried sludge has many beneficial uses, however, the absence of a viable market continues to
preclude public orientation, promotion and acceptance.
Malcom Park is the oldest and largest drainage area which comprises the downtown commercial
area with approximately 2,500 � 3,000 customer properties. Most of the sewers were replaced
with vitrified clay and PVC pipes. The final collection point is at the Malcolm Park Primary
Treatment Facility which was upgraded and commissioned in August 1993. The sewage is
screened before lifted to the primary settling tanks and the sludge is drawn off and carried to a
septage receiving site, which the effluent is discharged down a deep disposal well with a depth of
740 feet. The plant receives on average 3.0 million imperial gallons/day (MIGD).
The original sewers in the Yellow Elder Gardens/Oakes Field area were a part of the Royal Air
Force Housing Development (1940). This system unfortunately was unable to be fully utilised
after the subdividing and redevelopment of the properties as most of collection system were now
of private properties and access to it was limited. To accommodate a governmental low cost
housing project, a vacuum system was implemented in 1960 which was later converted to the
conventional gravity sewers in 1989. This area encompasses approximately 10 miles of sewers
with the final collection site being the Yellow Elder Gardens Treatment Facility. The plant
receives approximately 0.45MIGD.
The south-eastern district is comprised of several private subdivision developments with
approximately 10 miles of sewers. They have all been constructed within the past 12 years, but

the system is not fully utilised due to the moderate rate of development. The flows final
collection point is the Fox Hill Treatment Facility which averages about 0.4 MIGD.
Both the Pinewood and Flamingo Gardens drainage areas comprise of approximately five (5)
miles of sewers each. The wastewater collected is disposed into deep wells without treatment
pending the completion of the wastewater treatment facilities. The facilities treatment capacities
are both 0.5 MIGD.

National Plans for Sewerage Works
Nationally, it is envisioned that subdivision development will help propagate the elimination of
septic tank systems. This orientation is manifested by the on-going practice of septic tank
installations at property roadside frontages to readily accommodate connection to a future
centralise sewerage system on becoming available.

Conclusion
In the Bahamas, the adequate operation and maintenance of the secondary treatment plants play
an integral part in the effectiveness wastewater collection, treatment and disposal. As a
developing country, the interest and inclination are in the most appropriate technology for the
climate and the environment, and which would especially protect the groundwater resources.
Through application of the most appropriate technology, the country is committed to protecting
and promoting a pristine environment so vital to the people's health and the community's
economy.

Domestic and Industrial Wastewater Treatment Techniques in Barbados
Anthony S. Headley
Deputy Chief Environmental Engineer (ag), Environmental Engineering Division
Ministry of Health and the Environment, Culloden Farm, Culloden Road, St. Michael, Barbados
Tel: 246-436-4820/6, Fax: 246-228-7103, Email: msquared@surf.com

1.0 Introduction
At present, Barbados can be defined as a small island state whose economy is in transition. The
country has sustained economic growth for the last four years, life expectancy is increasing for
the population while conversely, more chronic diseases are treated in the health care system. In
the environmental management field, recent studies are indicating that the ground water
resources are showing signs of stress from human activity both in terms of quality and quantity.
The marine water quality is deteriorating which corresponds to a reduction in the diversity and
abundance of coral reef systems and fisheries resources. Generally, Barbados is experiencing the
problems associated with commercial, residential, economic and political development, which
mirrors previous development trends displayed by the now developed world.
Since 1992, policy makers have been engaged in constant discussions on sustainable
development with a systematic, controlled approach to sustainable development policy
implementation. One of the main questions asked at discussions, which is relevant to all
concerned stakeholders and Barbadians is, how can we preserve the quality of our environment
for our enjoyment and the enjoyment of generations after us ?
Right now, you are probably wondering what does this have to do with domestic and industrial
wastewater treatment. However, before one can appreciate the state and urgency of wastewater
treatment and the management of treatment systems, one must appreciate the historical, existing
and future perspective, the relationships between social and economic trends and the impacts
these activities have on environmental quality. My presentation will provide an overview on
domestic and industrial wastewater treatment in Barbados, but I will try to connect this to the
sustainability development concept being advocated.

2.0 Present Wastewater Treatment Methods
2.1 History of Wastewater Treatment
Barbados is a unique geological marvel of the Caribbean. Eight-five (85%) of the land mass is
Pleistocene Coral Limestone underlain by oceanic or impermeable clays. The other fifteen (15%)
is composed of mainly clays, shales and sandstone and is situated in an area known as the
Scotland District on the north east coastline in the parishes of St. Andrew and St. Joseph. When
evaluating disposal options, the geology and hydrogeological characteristic of the soils are key
factors in determining the appropriate method(s) for final disposal of wastewater. Nine soil
classifications have been identified and are presented in Figure 1.

Like most other countries, pit latrines were utilised for centuries as the appropriate means for the
final disposal of human faeces, gray (kitchen and bath) water and storm water. In the late fifties
and early sixties, studies done by Senn and Tullstrom made certain recommendations, which are
still utilised to this day.
As a result of these studies, a national zoning policy for the protection of the island's ground
water reserves and the control of domestic and industrial wastewater was instituted in 1963.
Table 1: The Principal Features of the Development Control Zones provides the development
restrictions for domestic and industrial wastewater control. Figure 2 provides a pictorial
representation of these control zones. As you can see, the entire coastal strip is designated as
control zone 5 and ironically, most tourist related developments and activities occur in this zone.
Table 1: The Principal Features of the Development Control Zones
ZONE
DEFINITION MAXIMUM
DOMESTIC CONTROLS
INDUSTRIAL CONTROLS
OF OUTER DEPTH OF
BOUNDARY
SOAKAWAY
PIT
1
300 day travel None allowed
No new housing or water No new Industrial
time
connections
development

No changes to existing

wastewater disposal except

when water authority secures

improvements

2
600 day travel 6.5 m
Septic tank of approved All Liquid Industrial wastes to
time
design, discharged to soak be dealt with as specified by
away pits

the Water Authority

Separate soak away pits for

toilet effluent and other
domestic waste water

3
5-6 year travel 13 m

time
New premises or alterations to
new existing systems must be

certified by the Environmental

Engineering Division

(Ministry of Health and the

Environment)

4
Extended to all No Limit
No storm runoff to sewage Maximum Soak away pit for
high lands
soak away pit
domestic waste

No new petrol or fuel oil tanks

5
No Limit

Coastline
As above for domestic
wastewater disposal
Petrol or fuel oil tanks of
approved leak proof design
No restrictions on domestic
wastewater disposal
Petrol or fuel oil tanks of
approved leak proof design
No restrictions on domestic
waste water disposal
Siting of new fuel storage
tanks subject to approval of
water authority

2.2 Package Treatment Facilities
The Public Health Engineering Division (now the Environmental Engineering Division)
originally approved most private wastewater treatment facilities approximately twenty years ago
in the 1970's. These facilities were traditionally installed at tourist related establishments
(hotels). Today, twenty tourist related establishments have package wastewater treatment
systems, while only one known agricultural and industrial establishment have installed systems
to improve the quality of their wastewater prior to sub-surface discharge.
Table 2 also indicates that based on the limited monitoring efforts (quarterly sampling) by the
EED, effluent discharges are consistently of a poor to average quality. Few treatment facilities
meet their BOD5 design specification, which range between 20 mg/L to 30 mg/L or comply with
adopted standards for BOD5 of 25 mg/L by the EED. Of the twenty three (23) operating
treatment plants, 8.7 % produce a good quality effluent while 43.5% and 26.1 % discharge
effluents of average and poor quality respectively to the environment. The effluent from twenty-
one percent (21.7%) of the operating plants is not monitored. These plants will be included in the
sampling scheduled for 1999.
There are several reasons why effluent quality does not meet the required design specifications
and discharge standards adopted by the Ministry. The main ones include:
1. there is a high probability that operators are not fully trained to operate existing sewage
treatment systems;
2. operators are not totally aware of the discharge guidelines and proposed discharge
requirements;

3. wastewater treatment is not viewed as a priority by most hoteliers and hence, maintenance of
most plants are secondary; and
4. the employee turn over rate is suspected to be a contributing factor. Persons originally
trained to operate the plant after it was installed are no longer employed by the
establishment.

2.3 Central Treatment Schemes
Currently, Barbados is constructing a 44 km sewer system capturing wastewater flows (11,300
m3/day) within the 6 m contour on the south coast for treatment at the recently completed
Graeme Hall primary treatment plant. The Master Plan for the West Coast Sewerage Treatment
Facility was presented to Government in September 1998 for final review and comments prior to
submission the Inter-American Development Bank for funding. The Bridgetown Sewerage
System has been in operation since 1982 and serves Bridgetown the capital. Sewer lines
extending from the Bridgetown Port Authority to Lower Bay Street however, connections to the
sewers were not mandatory so some communities in Bridgetown are not connected to the system.
This system discharges approximately two million gallons per day of treated wastewater to the
marine environment through a long ocean outfall.

2.4 Wastewater Reuse
Wastewater recycling is a practice which is becoming increasingly popular amongst hoteliers.
The water is mainly used for irrigation purposes in drip irrigation systems on golf courses and
flower garden. No standards have been adopted for wastewater reuse but standards were
developed and proposed for the West Coast Sewerage Treatment scheme.

3.0 Environmental Problems
Several problems can result from the lack of, or inadequate treatment of domestic and industrial
wastewater. Of main concern is the deterioration in the quality of recreational marine water.
Typical repercussions that are observed are: occasional fish kills at various surface water
locations on the island, algae blooms, reduction and diversity of coral reef systems and reduction
in the safety of the recreational marine water. Plans to perform epidemiological studies to further
evaluate the risk factors associated with recreational water are being develop.
When considering the practice of wastewater reuse, what springs to mind is the increase potential
for the transmission of water borne diseases and infections. The consequences are health and
economic based being closely related to the sustainability of the tourism sector. It should be
recognised that wastewater reuse increases the exposure pathways for human contact with
infectious agents and micro-organisms. If not managed properly, represents a danger to the
tourism sector and the fabric of the Barbadian economy.

4.0 Legislation
One of the legislative instruments C Barbados Water Authority Act C which governs wastewater
treatment, treatment facilities and effluent disposal was drafted with the understanding that the
enforcement agency would have been the Barbados Water Authority (BWA). However, the
Environmental Engineering Division has adopted the regulatory role for private and public
wastewater treatment systems.
The Division operates on the basis of limited legislative authority embodied in the Health
Service Act, 1969. There are two main legislative tools, the Disposal of Offensive Matter 1969
and the Nuisance Regulation, 1969, which are generally used by the EED to regulate private and
public wastewater treatment facilities.
A more focused legislation instrument C the Marine Pollution Control Act C which makes
provisions for the establishment of standards and guidelines has been drafted. It is expected that
this Act should be ratified by Parliament prior to year's end.

5.0 Plans for Wastewater Treatment Plants
These include:
1. implementation of the Marine Pollution Bill;
2. formation of an Environmental Standards Review and Assessment Committee
(ESRAC);
3. development of environmental guidelines and standards for water pollution
control;
4. operator will be required to perform mandatory analyses for key performance
indicators and report to the Ministry of Health and the Environment on plant's
performance; and
5. operators will require certification from a recognised academic institution
accredited by the Ministry of Health and the Environment to operate a
wastewater plant.
Table 3: Recommended Maximum Values For Treated Sewerage Effluent
Parameter
Maximum Value
BOD - 5
25 mg/ L
SS
30 mg/ L
Faecal Coliform
400/ 100 ml at point of discharge
Residual Chlorine
0.2 mg/ L

Table 4: Proposed Wastewater Reuse Criteria
Parameter
Value
Cane and Pasture Lands

Treatment Criteria (mg/L)
Secondary,<20 BOD5,<20 TSS
Disinfection Criteria (faecal Coliform/100 ml)
<2,500
Application rate (mm/yr)
<800
Location
Outside Zone 1
Golf Courses

Treatment Criteria (mg/L)
Tertiary < 10 BOD5,<10 TSS + N
Disinfection Criteria (faecal Coliform/100 mL)
Removal
Application rate (mm/yr)
<2
<800
High Rate Irrigation

Treatment Criteria (mg/L)
Tertiary <10 BOD5,<10 TSS, <5 T
Disinfection Criteria (faecal Coliform/100 mL)
N,<5 TP
Application rate (mm/yr)
<2
<2 to 3
Cash Crops
Tertiary <10 BOD5,<10 TSS + N
Removal

Table 5: Proposed Wastewater Reuse Criteria
Parameter
Value
Suckwells to non-potable aquifers

Treatment Criteria (mg/L)
Secondary,<20 BOD5,<20 TSS + N
Disinfection Criteria (faecal Coliform/100mL)
Removal
Application rate (m3 effluent/m2 suckwell)
<2,500
80
Irrigation Basins

Treatment Criteria (mg/L)
Secondary,<20 BOD5,<20 TSS
Disinfection Criteria (faecal Coliform/100mL)
<2,500
Application rate (mm/yr)
20 to 300
Suckwell configuration (L:W:D)
2:2:10
West Coast Sewerage Project
Technical Memorandum No. 11 Design Criteria/Parameters
by: Standley International Group Inc.
in association with Klohn-Crippen Consultants Ltd.
and Consulting Engineers Partnership

6.0 Conclusion
Wastewater treatment has an integral role to play in the protection and preservation of
environmental resources and the general health of the population. We must all play our part in
ensuring the environment is safe for our generation and generations after us. However, this role
doesn't stop at the installation of a wastewater treatment system. Owners, operators and
responsible government agencies must recognise that this is just the first step in a process of
continuous improvement. The development planning cycle for t he installation and operation of a
wastewater treatment system must make provisions to include long term operational and
maintenance cost and the cost to train and retain plant operators. When these vital elements are
neglected for large facilities, they become significant point pollution sources. A poorly
maintained and operated treatment plant is as effective as no treatment.

References
Barbados Water Resources Study Vol. I 1978
Bridgetown Sewage Re-use
Standley Associates Engineering Ltd.
Consulting Engineering Partnership Ltd.
Barbados Water Resources Study Vol. II 1978
Introduction, Summary and Master Plan
Standley Associates Engineering Ltd.
Consulting Engineering Partnership Ltd.
Feasibility Studies on Coastal Conservation
Nearshore Benthic Communities of the West and South Coast of Barbados: Importance, Impacts,
Present Status and Management Recommendations
Delcan 1993
Feasibility Studies on Coastal Conservation
Terrestrial Water Quality Report
Delcan 1995
Providing A Sustainable Water Supply for Barbados
Barbados Water Authority
Groundwater Pollution Risk Assessment for the Belle Public Water Supply Catchment, Barbados
Ministry of Health-Environmental Engineering Division, Bridgetown, Barbados
PAHO/WHO, Office of the Caribbean Program Coordinator (CPC), Bridgetown, Barbados
PAHO/WHO, Pan American Center for Sanitary Engineering and Environmental Sciences
(CEPIS), Lima, Peru,
British Geological Survey, Hydrogeological Group (BGS), Wallingford, Great Britain
June, 1989

Groundwater Pollution Risk Assessment for the Hampton Catchment, Barbados
Ministry of Health-Environmental Engineering Division, Bridgetown, Barbados
British Geological Survey, Hydrogeology Group (BGS), Wallingford, U.K.
Caribbean Environmental Institute (CEHI), Castries, St. Lucia
May 1991
Groundwater Pollution Risk Assessment for the Hampton Catchment, Barbados
Results of Monitoring in the Belle and Hampton catchment, 1987-1991
Ministry of Health-Environmental Engineering Division, Bridgetown, Barbados
British Geological Survey, Hydrogeology Group (BGS), Wallingford, U.K.
West Coast Sewerage Project Master Plan Report
Government of Barbados, Ministry of Public Works, Transport and Housing
Standley International Group Inc.
Klohn-Crippen Consultants Ltd.
Consulting Engineers Partnership Ltd.
May 1998

Domestic & Industrial Wastewater Treatment in Belize
Jose Mendoza
Environmental Officer, Ministry of Natural Resources & the Environment, Department of the Environment
10/12 Ambergris Avenue, Gelmopan, Cayo District, BELIZE
Tel: 501-8 22816/22542, Fax: 501-8 22862, Email: envirodept@btl.net

General Description and Overview
The land mass of Belize comprises 23,000 Km2 (8867 m2), located in Central America and
bordered to the north by Mexico, west and south by Guatemala and east by the Caribbean Sea.
Belize land mass includes 450 tiny islands known as cayes, totaling about 690 km2 (266 m2).
Belize has the second longest barrier reef in the world and the longest in the western hemisphere,
extending 200 km (132 miles). Belize has a total population of approximately 240,000 people of
various ethnic backgrounds of which a great proportion live in coastal areas. The Belize
economy is highly dependent on industries based on environmental resources: tourism,
agriculture, and fisheries.
Approximately 57% of Belize�s territory is still under closed cover forest and some 38% of
which are under some form of protected status. Most water resources, with the exception of some
important marine habitats and spawning grounds such as mangrove habitats, remain in relatively
pristine condition. The relative healthy condition of our environment can be attributed to several
reasons: i. perhaps due to the relative low population density and therefore the reduced pressures
on the exploitation of our resources and ii. the fact that the country has pursued an aggressive
environmental resource management policy.
Despite all our efforts, however, the country is presently faced with threats to its water resources,
these include: i. an increasing (solid and liquid) waste problem; ii. point and non-point source of
marine pollution from land-base sources and transboundary movement of wastes that degrade the
coastal zone; iii. development pressures on coastal areas and cayes due to the demand for tourism
and other recreational activities.

Sources of Contamination:
Water bodies are the major receptacles for the disposal of liquid wastes. Pollution of rivers from
domestic, industrial and agricultural sources is by far the largest tributary of pollutants to the
marine environment. With the increase in tourism, the problem associated with wastewater
disposal has become more acute. Fragile ecosystems particularly small islands are exposed to
heavy pollution from sewage waste. In consideration of the fact that most communities depend
on surface water for potable water makes water pollution the principal contamination problem
facing Belize. Fragile ecosystems, particularly small islands, are more vulnerable to heavy
pollution from sewage waste. Belize City and San Pedro and to a lesser extent the capital,
Belmopan, are the only urban areas that are fully served by a sewerage system. In addition to

these municipal sewerage systems, several industries have their own wastewater treatment
facilities.
In Belize, the major agricultural export crops are sugar, citrus, banana and aquaculture. These
agricultural crops all require the input of agrochemicals and as such contribute to some of the
main non-point source of pollution. However, this paper will deal solely with domestic and
industrial point sources of pollution.

1. Domestic Source:
The domestic sources of pollution are a combination of wastes from residential areas, hotels and
commercial establishments. These wastes include; water from the laundry, kitchen, bathroom,
etc. In the case of Belize City, about 40% of the residents are serviced by a sewer system with
the facultative lagoons for treatment and final disposal before discharging the treated effluent
into the sea. The mangrove buffer between the sea and the facultative lagoons serve as further
treatment of the water.
The other households and other sectors that are not serviced by the sewer system use the
individual septic tank system with a soak-a-way or leach field for their wastewater treatment
facility. Many people live along the flood plain and during the rainy season several rivers over
flow their banks and the septic system or pit latrine becomes inundated with the wastes entering
the rivers causing serious contamination affecting both the public's health and the environment.

2. Industrial Effluent:
Industrial effluent is primarily generated by the food processing industries since Belize has no
heavy industry. The issue of primary concern with respect to these industries are those associated
with organic loading. Some of these industries include the soft drink industry, brewery, distillery,
citrus processing, sugar processing, aquaculture, poultry, dairy, meat processing among others.
Effluents from these industries have contributed to the contamination of some of our water
bodies as they dispose there effluent in similar ways, either directly or indirectly into rivers and
streams with little or no treatment. Some small factories utilized special designed septic tanks
with leach filed to dispose there effluent. A few of the larger industries such as the sugar
industry, the shrimp processing industry among others utilize facultative lagoons for primary and
secondary treatment of their effluent. Several other industries are at the stage where they are
currently designing and constructing adequate treatment facilities to meet the Effluent Limitation
Standards since the implementation of the Department of the Environment's effluent discharge
licencing programme. The establishment of new industries or factories are dealt with through the
Environmental Impact Assessment (EIA) process where utmost consideration is given to ensure
that clean technologies are implemented for the processing of their products and the treatment of
their effluent.

Existing Water & Sewerage Systems:
1. Septic System:
The most common type of subsurface disposal system includes a septic system and a seepage pit
or leaching field. The tank serves to store settled and floating solids and the leaching field serves
to distribute the effluent so that it can percolate through the soil. Decomposition of organics
takes place under anaerobic condition. A buried septic tank is used to provide the necessary
primary treatment step, as well as to act as a sludge storage tank. To ensure proper operation and
a long service life, septic tanks should be pumped clean on a regular basis every few years. Only
sealed septic tanks to prevent leakage are currently being approved. The use of septic tanks is
recommended primarily in those areas outside the sewerage system service area and where the
permeability of the soil allows for the proper functioning of the tanks and leach field. In addition,
housing projects are being required to install low flush toilets to minimize the volume of water.

2. Facultative Lagoons:
The Belize City Water System currently includes a 3.0 million U.S. gallons per day (USGD)
water treatment plant on the Belize river. The sewerage system in Belize City serves about 40%
of the population of Belize City. It consists of conventional gravity sewers in 15 zones where
sewage is collected at a central pumping station and pumped to a neighbouring zone towards the
treatment works. Treatment is provided by a 2 two-cell facultative sewage lagoons located on the
south side of Belize City. The lagoon cells operate in parallel and each is designed to provide 10
days hydraulic retention time. Currently, plans are underway to expand this facility with two
additional cells. Treated effluent is discharged into Sibun Bight through a canal that runs through
the mangrove wetland in which the lagoons are located. San Pedro Ambergris Caye sewage
treatment system consists of three facultative lagoons with impermeable layers at the bottom
(unlike Belize City�s system). It has a capacity of 600,000 g.p.d. After treatment, the
unchlorinated effluent is discharged into the surrounding mangroves for polishing before
entering the surrounding water. There are plans to expand the service area and treatment
capacity, in the near future, in areas that are not serviced by the sewer system.

3. Biogas:
The technology currently being advocated for sewage management for small islands is toilets
fitted with composting or biogas tanks. There is considerable experience with biogas tanks which
are being tested and promoted by the Biogas Unit of the Ministry of Agriculture. In 1993 a 5m3
digester to treat human waste was constructed at Central Farm quarters. The result obtained have
been very promising as shown by water tests conducted by the Health Department at the Belize
City Lab. The results have shown that the Biogas plant works better in preventing contamination
than a septic tank. Construction costs were also lower for the biogas plant than the traditional
septic tanks. Biogas plants have also been used successfully in Belize to treat pig and cattle

manure. Advantages which have been observed with the use of these plants for human waste
treatment compared to latrines are:
- construction can be done in any soil type clay soils as well as sandy soils;
- This plant can be constructed even in areas where water is scarce since these
do not need much water;
- improved sanitation control, compared to pit latrines, and can be built for
communities as well as for individuals to prevent nightsoil dumping into the
sea or nearby streams and rivers;
- end product can be used as fertilizer for ornamental and fruit trees;
- a soak away or a fertilizer pit may be constructed at the over flow;
- biogas may by used instead of compressed gas in remote areas;
- use of organic and inexpensive fertilizer could be used to landscape areas for
prevention of erosion;
- the anaerobic process kill and/or controls pathogens by fermentation inside
the digester.
Currently, there are a total of 31 biogas plants in Belize. However, these plants have all been
constructed on the mainland where the watertable is high. The success on the islands has not
been tested. However, there are plans to test the effectiveness in preventing pollution on the
islands. Permission has been granted, through the EIA process, to establish the biogas system to
be used at a resort in Nicholas Caye, a small island in southern Belize.

Alternating Intermittent Recirculating Reactor (AIRR System):
The AIRR system is an innovative alternative for the conventional drain field. It is designed to
treat effluent in areas where percolation is limited or non-existent so the land can still be used for
homes or business. Its biological process is natures way of clearing up waste water. This system
creates colonies of different types of bacteria, they are cannibalistic in nature, and eat or destroy
each other, the results is clear water. This clear water is ready for reuse in above ground
irrigation discharge into waterways or to drain underground.
This system is presently being used in Hunting Caye, the largest of the six cayes of the Sapodilla
Cayes located in the south and has approximate area of six hectares. This system is also
recommended for other islands especially those with high tourism potential.

Fiberglass Septic Tanks:
Apart from the traditional two or three chamber concrete septic tanks, the use of fiberglass tanks
is becoming more widely used in the country. The fiberglass septic tanks consists of multiple
layers of glass fiber material that has been saturated with a corrosion resistant resin. This results
in a fiberglass laminate that is much stronger and more rigid than non-laminated plastics. The
strength, pound for pound, is even greater than steel. It is believed to be 100% water tight,
corrosion resistant, lightweight and excellent for high ground water application. These tanks are
currently being encouraged for karst topography areas such as the northern areas and low lying
area of Belize where the water table is high.

Wetland System:
Only one resort, located on the southern coastal area of Belize is using the Wetland Wastewater
Treatment facility. This system is considered to be an ecological wastewater treatment system. It
is believed to be a 100% ecological system, anaerobic - aerobic with two components;
1. a watertight, underground tank for settling out solids and
commencing microbial decomposition (anaerobic); and
2. a cement-lined surfaced flow, created wetland with both
floating and emergent (soil rooted) wetland vegetation.
The basic principle is the biological mechanism of contaminants removal, including;
- Physical
sedimentation: anaerobic process in septic tank. It removes -
coliform, nitrates, organic phosphates, bacteria and virus.
- Filtration: particles are filtered by passing through water substrates and the
roots of the plants. It removes - sedimented solids and colloidal solids.
- Absorption: absorption though substrates, plant roots and by force of particle
attraction. It removes - colloidal solids, phosphates, heavy metals, nitrogen
and refractory organism.
- Chemical Precipitation: formation of coprecipitation of products with
insoluble components. It Removes - phosphates and heavy metals.

Some of the benefits using this system include:
- low cost, low energy or no energy process requiring minimal operation
attention;
- reliable and cost effective treatment;
- high level of effective treatment and contaminant removal;

- lack of odours, mosquitoes and other insect vectors;
- minimal cost of operation and maintenance system;
- ornamental function by the addition of flowers and plants, green areas and
integration in the landscape.
Currently, the above mentioned wastewater treatment systems are presently being utilized in
Belize for a variety of domestic, commercial and industrial effluent treatment. With the
enactment of the Environmental Protection Act (EPA) and its subsequent regulations - the
Effluent Limitation Regulations and the EIA Regulations all new and existing industries must
employ environmentally sound systems to treat their waste water in order to protect the public's
health and to ensure a safer, cleaner and healthier environment.
Good wastewater and sewage disposal and treatment is important for the protection of the
environment, to promote good public health and to protect the tourism industry itself. Whatever
system a household, community or industry utilizes it must be designed and maintained properly
to ensure that it works the way it was intended and to maintained its integrity to ensure the
protection of the environment and the public's health. As time goes by, new and improved
environmentally friendly systems must be developed and promoted at reasonable cost to all
sectors.

References:
Alterating Intermittent Recirculating Reactor (AIRR System). SPEC Industries, Inc.
Arthur B. Archer, Consultant, Land-based Sources of Marine Pollution Inventories. UNEP
Regional Coordinating Unit. Countries: Belize, Cayman Islands. May 1994
Cross E. William. Environmental Assessment of the Proposed Water & Sewerage Expansion,
Belize City, Belize. June 1995
Ecological Subsurface Flow Constructed Wetlands Systems for Wastewater Treatment. Planetary
Coral Reef Foundation.
Fiberglass Tanks for Water and Waste Water Collection and Process Systems, Submittal
Documentation. Fiberglass Solutions International.
Health and Environment, A National Plan for Health and Environment in Sustainable Human
Development. Belize, August 1997

Adopting, Applying and Operating Environmentally Sound Technologies
for Domestic and Industrial Wastewater Treatment in the British Virgin
Islands
Mr. Mukesh Ganesh
Engineer, Water & Sewage Department, Min. of Communications & Works
PO Box 130, Roadtown, Tortola, BRITISH VIRGIN ISLANDS
Tel: 284-494-3416/7 ext. 5797, Fax: 284-494-6746, Email: water@caribsurf.com

1 Introduction
The British Virgin Islands (BVI) is made up of about fifty small islands located in the Lesser
Antilles in the Caribbean Sea. The largest island, Tortola, is only twenty-four square miles in
area with it's capital Road Town. Other islands that have some significant population includes
Virgin Gorda, Jost Van Dyke and Anegada. Public water supply is only available in Tortola and
Virgin Gorda and two separate sewerage systems are in Tortola. The BVI has a current
population of 19,482.
Sewage disposal in the British Virgin Islands has classically been by either direct dumping in the
ocean or by the use of septic tanks and soak away or field beds. The direct discharge of raw
sewage to the ocean is practiced in the BVI by residences and businesses along shorefronts and
by yachts anchoring in the many harbours and bays. In these areas where swimming, snorkelling
and scuba diving are tourist pastimes, direct discharge of raw sewage to the sea is not entirely
appropriate. In the capital, Road Town, sewage is collected by gravity sewers and channelled to
wells from where it is pumped into the ocean. Intermittent disinfection of the wells is carried out.
In many other areas, there have been ongoing complaints of flows of septic tank effluent across
public thoroughfares and into neighbouring properties. In the BVI, there are few, if any, areas
where simple land disposal of sewage would be practical, in part due to the shallow depth of
topsoil throughout the islands. Recently the first public sewage treatment plant with capacity of
treating 45,000 gallons per day has been commissioned to serve Cane Garden Bay in Tortola.
This plant is a sequencing batch reactor (SBR) with three parallel tanks. In Anegada pit latrines
are used in addition to water closet facilities and these are now contaminating the few water
wells the residents are using to obtain their fresh water supplies. Anegada is a flat island made up
of coral limestone and it is difficult to construct septic tanks and pits for latrines.
The nature of the sewage generated in the BVI is mostly of a domestic nature. Laundromats
produce most of the industrial waste. There is no major manufacturing industry in the territory.

2 Options of Technologies Available
Sewage can be treated to various extents and by a variety of different methods prior to disposal.
These range from a total lack of treatment to full biological treatment with tertiary treatment for
disinfection. Some options of technologies available are:-

- disposal of untreated sewage,
- septic tank and on site disposal,
- chlorination and disposal of sewage,
- primary treatment mainly by settling in clarifiers or sedimentation basins,
- secondary treatment. Some of the more commonly used biological processes
are:-

- activated sludge process including the sequencing batchreactor,
- attached growth biological processes (e.g. biodisccontactors and
trickling filters),
- aerated
lagoons,
- stabilisation
/ oxidation ponds.
- tertiary
treatment,
- combinations of the above, i.e., primary plus tertiary.
Other high tech systems for complete treatment of the effluent and sludge may be available but
may not be affordable in the circumstances.

3 Proposed
Treatment
The economy of the BVI is very dependent on tourism and it is the duty of the Government to
ensure that the environment is kept clean so that more tourists can be attracted.
In the BVI the sewage will have to be treated to some extent to ensure that the disposal of
effluent into the surface waters or the ocean does not adversely affect the ecosystem. Suitable
available land space is limited so any treatment proposed would eliminate treatment processes
such as stabilisation ponds, which take up a relatively large surface area.

4 Monitoring
Fecal colifor bacteria, an indicator of pollution caused by the presence of human waste, have
been monitored. Currently the Department of Conservation and Fisheries monitors the coastal
waters of the BVI. A 1988 report by Dillon Consulting Engineers of Canada referred to a
monitoring programme that identified Road Town and Cane Garden Bay as being the most
polluted areas in the territory. Government has since installed the treatment plant at Cane Garden
Bay and is formulating plans for treating sewage in the Road Town area. Since the installation of
the sequencing batch reactor at Cane Garden Bay, no results have been released from that area.
At the present time, yachts in the BVI do not require holding tanks for sanitary waste. The
practice which always has been followed is to permit direct dumping of sewage from yachts
whether at anchor or at sea. At Cane Garden Bay a yacht pump out facility has been constructed
and requires constant monitoring for it's effective operation.

5 Future
Directions
The Government of the British Virgin Islands has an extensive plan to improve sewage
collection and disposal in the territory. Besides the new system that was commissioned in Cane
Garden Bay in August 1998, the following new works are planned:-
- design and construction of a new sewage collection and treatment system for the eastern end
of Tortola. Here the treated effluent would be available for use as irrigation at the nearby
Agricultural Station, which uses expensive potable water for irrigation presently. Also the
treatment plant will help to eliminate the evidence of contamination arising from sewage
discharge into the ocean along the total length of the East End settlement. The sewage
generated from the planned expansion of the airport at Beef Island will be treated at this
plant.

- design a construction of a new sewage treatment plant in the vicinity of Road Town to treat
the sewage before disposing the effluent to sea. Minimal modifications will be needed on the
existing sewer system and secondary treatment would eliminate problems of contamination.
The possibility of water conservation and reuse hinges on the existence of an adequate
treatment system.

- design and construction of a new sewage collection and treatment system for the Valley,
Virgin Gorda.
Any system that is designed to operate in the BVI has to take into consideration that the islands
lying in the hurricane belt. Recent experience has shown that the SBR at Cane Garden Bay
operated well during hurricane Georges.

6 Conclusions
The following have to be taken into account to adopt, apply and operate environmentally sound
technologies for domestic and industrial wastewater treatment in the BVI.
- the primary concern is to produce an effluent that will not adversely affect the environment
especially in the contamination of the many beaches and harbours around the territory. The
technology selected may need to cater for tertiary treatment, thus a high quality of effluent.
- desalinated water is supplied for public's use and is quite expensive and with tertiary
treatment of the effluent there is the possibility of recycling the water for domestic
consumption or at least used for irrigation purposes.
- the disposal of sludge is also of paramount importance and the Government is now making
initial preparations to have a suitable area designated for the construction of a drying bed.
Septage from septic tanks and sludge from waste water treatment plants should be dried and
can be used as a soil conditioner in agriculture.

- that septic tanks with soak away are not an effective means of wastewater treatment and
disposal in the BVI because the top soil is too thin for effective biological breakdown of the
effluent.
- the importance of monitoring cannot be over emphasised. More detailed tests for coliforms
and nutrients should be carried out at more locations. The Ministry of Natural Resources and
Labour, Department of Conservation and Fisheries are doing these tests.
- legislation should be enacted to force yachts to be retro fitted with holding tanks for waste
which should be discharged at approved locations where the sewage can be conveyed to a
waste water treatment plant. In addition, steps should be taken immediately to limit overnight
mooring of yachts to those that have holding tanks.

Domestic Wastewater Treatment in Colombia
Dr Cruz Fierro
Direccion Tecnica de Desarrollo Sostenible. Ministerio del Medio Ambiente, Calle 37 No. 8-40
Santafe de Bogota, COLOMBIA
Tel: 47-1 338-4900 ext. 430-429, Fax: 47-1 288-9725, Email: cruzser@hotmail.com

Introduction
This document presents a partial vision on the state of the treatment of residual waters in
Colombia. This paper will focus on the municipal wastewater treatment, due mainly to the fact
that the information on the treatment systems used by industry is dispersed in different regional
entities (34 regional environmental authorities - CAR�s) which have the competence and
attribution to determine the characteristics of the wastewaters to be disposed and the type of
treatment technology that it must install by industry, this is done depending on the environmental
characteristics on each zone where it is located each type of industry.
Opposite to the information about treatment systems used by industry, the information on the
treatments of the domestic wastewaters is more aggregated and centralised, due to the fact that
the treatment of these waters is in charge by Pubic and/or Private Own Treatment Work Systems
(POTWS) under the control by Governmental Entity.

State of Wastewater Treatment
The promulgation of the decree 1594 in 1984 mandates that any company that disposes any
effluent into any water body, it has to treat these waters to meet certain legal environmental
quality requirements before to be disposed.
This legislation led the industrial companies to the implementation of some type of waste water
treatment, so this caused that up to now the majority of formal industry of the country haven
treatment systems. With respect to type of installed technology exists a high variety that
fundamentally depends on aspects as the type of industry, its size and the obligations imposed by
the CAR.
With respect to the urban centres, the above decree requests that their wastewaters to be treated,
this has not been accomplished and today the most used method for the disposal of the municipal
wastewaters in the rivers does not include any previous treatment.
Only during the last 5 years, the four more important urban centres of the country (with more
than one million of people) have begun to construct wastewater treatment systems. For example,
the city of Bogota with almost 6 million of people will have and the end of 1999 a primary
wastewater treatment system that will treat the water generated by approximately two million of
inhabitants and it is foreseen to have a water treatment for all the population by the year 2020,
though it exists uncertainty on the future financing of this project .

The current situation of Colombia related to its domestic wastewater treatment is that 10% of the
municipalities make some type of treatment of their waters, with an extent of the 16% of the
population of country. Now it exists a series of projects underway to provide treatment plants to
other 112 municipalities so about 3.5 million of persons will be benefited through this service.
To this it is expected that 20% of municipalities have their own treatment systems.
The most majority of these municipalities have adopted the type of treatment called
estabilization ponds, and in a low proportion systems as trickling filters and activated sludge.
Though in the country had been installed technologies a long time ago as the UASB
(Bucaramanga), the open economic model established in the country in the years 90, permitted
the existence in the market of a great variety of technological offers that cover the great majority
technological options offered all over the world today.
The market trends indicate that the technological options are the following:
For the urban centres segment with population until of 20000 inhabitants, it is offered compact
plants generally based on some type of aerobic system.
For cities with more inhabitants it is offered the construction of treatment systems using
generally technologies as trickling filters or activated sludge, using stabilisation ponds as final
treatment.
The problem of the way of providing this type of technologies is that small cities have acquired
or they can acquire them that have a high operation and maintenance cost and with the limited
budget of these cities cause that these plants work at very low efficiency levels and in some cases
they are not operated or they are abandoned.
With respect to technologies for domestic and industrial wastewaters treatment, it is a policy of
the Ministry of the Environment not to recommend any treatment technology, since it considers
that its responsibility is to establish the parameters of quality of the water bodies and the
characteristics that it must fulfil a wastewater to be disposed and to the enforcement of its
compliance, in this way each company is free of choosing between the existing technological
offers that most fit its necessity and the work of the environmental authorities is to check that
with the technological option acquired meets the existing law requirements for disposing and
monitoring its compliance.
With respect to the future of the wastewaters treatment in Colombia, it presents the following
two features:
Related to industrial residual waters, the government issued the production cleaner policy in
which it is established between other objectives, the prevention and to minimisation the
generation of polluted charges ,from this point of view, it is pursued to go from the treatment
vision end of the pipe to the control in the source, because it is considered that with this strategy
can be achieved in a better way the decrease goals of the pollution generated by industry and the
reduction of dangers of the substances disposed.

With respect to the domestic wastewaters of urban centres which represent in many places a
great source of pollution of rivers, the government has designed a plan that includes; a) Priority
zones to construct treatment systems; b) an assessment of the efficiency of the existing systems;
and; c) the creation of regional financial funds for of the construction of these systems.
Additionally, with the implementation of the pollution charges, as an economic instrument to
improve conscious to invest in pollution control. It is expected that the CARs play an important
role for the technical and financial assistance in the construction of treatment plant for the cities.

Updated Inventory of Localized and Non-Localized Pollution Sources,
Including Industrial, Domestic, Human Development and Port Wastes,
Furnishing Specific Alternatives as to How to Deal With Them.
Jos� Miguel Ram�rez Corrales
Costa Rica

Introduction
In the frame of GEF RLA/93/G41 Regional Project, the present study, which includes "Updated
inventory of localized and non-localized pollution sources, including industrial, domestic, human
development and port wastes, furnishing specific alternatives as to how to deal with them" is
thus established as integrating part of it at the short, middle and long terms and it is about this
issue that this paper has been developed.
In Costa Rica, the marine environment of Port Limon and adjoining coastline has been affected
by both natural and man-caused polluting mechanisms. For instance, both deforestation and
natural disasters have caused severe soil erosion and the dragging by streams of enormous
amounts of different sediments which have been deposited at the Caribbean shorelines.
Additionally, poor disposal of solid waste, the dumping of untreated waste water outlets from the
city, as well as industrial waste water and litter coming from boats and ships, are all factors that
affect the marine ecosystem and debase the natural coastline beauty. The pollution at this
shoreline has grown due to the weakness of enforcing mechanisms and administrative systems
that have to do with urban planning, industrial growth and proper soil use (soil-use capacity).
The specific objective of this study was to carry out updated inventories of localized and diffuse
pollution sources of the marine and coastal environment of Port Lim�n, Costa Rica, and
adjoining areas, including industrial and agricultural discharges, domestic waste water outlets,
port and urban development waste, along with specific alternatives as to how to deal with them
in the short, intermediate and long terms. The present study is focused on the area located
between Moin and Limon's airport. This is the area where both pollution and different human
activities are most concentrated along Costa Rica's Caribbean coastline which is 212 k. (133
miles) long. The area of influence in this inventory comprises Lim�n centre which has 84125
inhabitants (as of 1988). The total area of this province is of 9188 km2 (3590 miles2). The area in
the inventory has 1766 km2.
The following have been identified as the main pollution sources that add to the negative
environmental effect upon Port Limon's sea water:
� Domestic waste water from urban areas which are dumped with no previous treatment
directly to the shoreline or through receiving streams (or creeks) in the area.
� Solid waste from urban areas and the Hospital .
� Only about half of the garbage is collected to be delivered to the municipal dumping
ground, due to the fact that local municipal and port authorities lack ability to enforce
existing laws.

� Agrochemicals (fertilizers and pesticides) coming from the agricultural area found North
of the study area.
� Hydrocarbons from National Petroleum Refinery, RECOPE, fishing boats and cargo
ships.
� The polluting load coming from the middle and upper basins of the rivers that flow into
the ocean along this shoreline, as well as sediments from agricultural and urban areas.
� Industrial dumpings and outlets.
� Port facilities and their activity.

Main Results
It has been possible with this consultorship, during the time span between August 1996 and June
1997, to identify and set priorities as to the main pollution problems to be found at the region of
study, based on the reviewing of the existing information about the inventory of localized and
non - localized pollution sources, which are herewith detailed.
The lack of an adequate landfill and proper management of different types of solid waste, as well
as the pressing need for an efficient disposal system of hospital waste, constitute the region's
main environmental problem, a short-term solution to which must be provided.
As far as untreated sewage waters which are dumped along the shoreline, I.C.A.A. (National
Institute of Aqueducts and Sewage Systems) has undertaken the refurbishing of 40% of the
sewage system network. Additionally, initial studies are being carried out as to the laying out of
an underwater discharge outlet of domestic waste water 700 m. (2300 ft.) away from the coast.
The main sewage discharge of the Vargas Park main sewer shows typical levels of raw waters
with B.O.D. over 200 mg./L, oils and greases at 306 mg./L, phosphorus at 2.7 mg./L and total
nitrogen at 25 mg./L.
The discharge of untreated sewage waters off the shoreline which have been detected in the
study, has forced to declare certain beach areas as forbidden for public use, as for instance the
Municipal Swimming area of Port Limon, showing levels of 35100 bacteria per 100 ml.
In the area of the lower basin of the Limoncito river, there are certain industrial plants such as
ENVACO (Industrial Packagings of Costa Rica) and DECAR (Cardboard Dept. of Standard
Fruit Co.), which have low-efficiency waste treatment systems that are not able to furnish proper
discharge quality of the final effluent. Thus, for instance, ENVACO's discharge outlet #2 in the
first monitoring campaign showed a pH of 9.47, B.O.D. of 4980 and C.O.D. of 12680 mg./L. At
the second stage, the monitored levels were 10.45 for pH, B.O.D. of 51000 mg./L and C.O.D. of
76400 mg./L.
ENVACO's discharge outlet #2, represents the outlet of a wastewater treatment plant and shows
a pH of 10.1 and 10.45 in both monitoring campaigns. In DECAR's case, the treated effluent's
discharge has a pH of 5.45, a B.O.D. level between 588 and 690 mg./L and a C.O.D. level
between 918 and 1129 mg./L. These levels do not comply with the quality standards required by
local legislation.

Other industrial plants such as Coca Cola discharge wastewaters directly to the environment onto
receiving streams, showing pH levels of 11.77 and 11.85, B.O.D. between 1707 and 8770 mg./L
in outlet #1 and between 590 and 3055 mg./L in outlet #2, as well as C.O.D. levels from 3640 to
12850 mg./L for outlet #1 and 1055 to 4500 mg./L for outlet #2.
The banana plantation activity basically furnishes organic solid waste such as the pinzote
(banana rackies), fruits that have been rejected for market and plastic bags used to envelop the
banana bunches. To a certain degree, this activity also adds to the sedimentation produced
downstream caused by some drainage systems that don't consider soil - protection measures.
Despite that, there are certain plantations such as DOLE's La Paz, which set an example as far as
the management of banana rackies, plastic waste and leftover bananas. Wastewaters from
DOLE's La Paz processing plant showed B.O.D. levels from 18 to 22 mg/L and C.O.D. from 40
to 82 mg/L.
The concentration of hydrocarbons in coastal waters show very low pollution levels, from 1.00 to
1.85 ug/L in 3 samples that were analyzed, which is much lower than UNESCO standard of 10
ug/L of crisene. This fact reflects the excellent treatment conditions of RECOPE's (National
Petroleum Refinery) facilities.
The diffuse or non-localized pollution, due to the seaport activity of large ships and small boats
along the shoreline is mainly caused by the latter, since the larger ships follow the International
Maritime Organization's recommendations and discharge beyond 10 nautical miles from shore.
The dragging of sediments caused by deforestation and other natural phenomenae in the region,
is the main source of pollution of coastal waters on coral reefs. It is believed that along with the
sediments, the pesticides used in agricultural activities in the region, are also dragged along.
From a hydrographic and oceanographic point of view, the information consulted as to the
dispersion of pollutants in the coastal environment is scarce, incomplete and is not up-to-date, so
that it doesn't allow a proper quantitative nor qualitative analysis about the possible pathways of
pollutants along Limon's shoreline and adjoining areas, nor as to which would be their probable
direction followed once moving away from the port.
It is important to point out that besides the above-mentioned pollution problems, the region of
Limon was affected by an (7.4 Richter scale) earthquake in 1991 which destroyed previously
existing city's drainage system, additionally affecting the sea bottom level (which rose 1.5 m. or
5 ft.), thus making it necessary to dredge the port facilities area. April 1991's earthquake, caused
an uplifting of the sea bottom, leaving coral reefs and domestic waste water outlets totally
exposed. This caused Portete beach to disappear and the death of 5% of the region's coral reefs.

Main Priorities to Control and Minimize the Pollution
This study identifies the following priorities so as to control and minimize the pollution of
shoreline waters at the short and intermediate term:

� The need to carry out technical and economical studies for the placement and functioning
of a proper landfill for domestic and hospital waste. The possibility of using the region's
railway infrastructure is recommended.
� The implementation of gathering sites for the recycling and reusing of waste materials,
including used lubricant oils.
� To initiate hydrographic and oceanographic studies which would support the adequacy of
the underwater outlet's discharge site. Necessary studies for this purpose would be: a)
Measurements of marine currents with the aid of a network of current-measuring devices.
Updating of region's climatology. Tide measurements with the aid of a tide-measuring
device. Batimetrical map lay-out at a 1:2000 scale of the shoreline zone, especially of
proposed area for placing waste water discharge outlet.
� To carry out technical and economical studies regarding the possibility of building a joint
industrial waste water treatment plant that would look after the needs of the industrial
plants found at Limoncito river's lower basin.
� To propose implementing an environmental assessment so as to study occupational health
hazards at banana plantations.
� Information about pesticides in water suggests that forthcoming studies should focus on
the sediments dragged by streams and their effects on living organisms and not
necessarily on the water itself.
� To speed up environmental impact study, design and construction of underwater waste
water discharge outlet, with the purpose of diminishing fecal pollution of beach waters.
� To inform potential swimmers of danger involved in bathing at Piuta and Municipal
Swimming beaches.
It is crucial for marine and coastal resources to be sustainable in order for the region's
biodiversity and human health to be protected while enhancing its economic development. At a
regional level, the part to be put into practice with this work, along with the rest of the major
study's sections and selected areas, will contribute to the protection of international ocean waters
and will allow the minimization of forthcoming environmental impact cases that would hinder
development and economical activities, through institutional strenghthening and the
enhancement of international cooperation.

Cuba: Technologies For Wastewater Treatment and Disposal -
Current Status and Performance
Eng. Carmen C. Terry Berro
Senior Specialist, Environmental Agency, Ministry of Science, Technology and Environment
Calle 20 Esquina 18A, No. 4110, Playa, Ciudad de la Habana, CUBA
Tel: 537-229351/296014, Fax: 537-249031, Email: cterry@cigea.unepnet.inf.cu

Introduction
Among the highest priorities established in Cuba's Environmental Strategy, the application of
environmentally sound technologies for wastewater treatment and disposal is receiving special
attention, taking into consideration that the inadequate liquid waste management has been
identified as one of the most significant shortcomings in the country's environmental work
during the present decade.
The National Inventory of Point Sources of Pollution reveals that 42% of the identified sources
are human settlements and social facilities, while 33% and 25% are industries and livestock
facilities, respectively. Only 54% of these polluting sources have some wastewater treatment
system; the remaining percentage discharges their untreated wastewaters to inland and marine
waters.
To achieve the goal of gradual decrease of the polluting loadings disposed of to the environment,
a diagnosis of the situation of wastewater treatment and disposal has been made, including basic
information on the current status of the technologies used for this purpose and the perspectives of
improving their choice, application and performance.

Municipal Wastewater Treatment and Disposal Systems
In 1997, 90.4% of the Cuban population had access to sanitation services, provided by sewerage
systems (34.2%), septic tanks and latrines (56.2%). It has been estimated that only 17% of
wastewater collected by urban sewerage received some treatment last year.
A narrow range of technologies is being used in our country to treat domestic wastewaters and
dispose of the effluents. These technologies can be grouped as follows:
� Five conventional trickling filter (rock-filled filter) plants in critical situation due to
equipment failures, the lack of maintenance and spare parts and operating problems. Only
one is functioning, providing primary treatment. The remaining plants are out of
operation.
� Around 1 250 stabilization ponds distributed throughout the national territory. Most of
the systems consist of one facultative cell. Although this type of technology is considered
an appropriate option for our country's conditions, many existing systems don't have an

efficient functioning because of design problems, hydraulic and organic overloading,
starting up problems and the lack of maintenance.
� On-site treatment and disposal systems for wastewaters coming from small communities,
individual dwellings and other facilities. The most typical system consists of a grease
interceptor tank as pretreatment and a septic tank followed by a soil absorption field for
final treatment and disposal. When soil disposal can't be used, the most common
alternative is septic tank in conjunction with granular-medium filters (downflow or
upflow type) and effluent discharge to surface waters.
� Improper design and the limited capacity of the operating companies to meet the cleaning
schedules of septic tanks, are factors that have influence in the poor performance of these
technologies. In many settlements, latrine seepage percolates down and reaches
groundwater used for human consumption.
� A few package plants in tourist zones based on activated sludge processes, that provide
treatment to wastewaters from hotels. Some of these plants treat wastewater to tertiary
level to reuse effluents for irrigation of lawns and gardens. They were recently built and
in general, their performance is satisfactory.

Industrial and Livestock Wastewater Treatment and Disposal
Industries located in cities with sewerage coverage, usually discharge their liquid wastes with no
pretreatment into municipal collection systems. Others, only provide partial treatment prior to
discharge into receiving waters.
Facultative and anaerobic ponds with aerobic cells as a final process to polish the effluent before
discharge, are widely used to treat livestock wastewater, as well as those industrial wastewaters
in which organic matter predominates. Around 500 ponds have been constructed in Cuba for this
purpose.
Our main economic activity, the cane sugar industry, requires special attention because of the
magnitude of the environmental damage that its facilities can cause. At present, wastewaters
coming from sugar mills are being used for the fertilized irrigation of the sugar cane plantations.
A great effort is being made to extend this practice to the totality of these facilities with proper
conditions to assimilate this technology.
Positive results have been achieved by using it; in addition to the substantial mitigation of
environmental pollution and the decrease of the cost of wastewater treatment facilities,
agriculture yield and sugar production have increased in the irrigated areas.
To avoid long-term affectations to the soils, internal measures are taken in the production
process, mainly the segregation, recollection and reutilization of the acids and alkalis used in the
cleaning of the technological equipment and the poured petroleum products.

The most common wastewater treatment technologies used in the major productive activities are
summarized in the following table.
SECTOR
MOST COMMON TECHNOLOGIES
Sugar industry
Grease and oil interceptor tanks
Stabilization ponds in series
Fertilized irrigation
Cannery
Stabilization ponds in series
Fishing industry
Oxidation ditch process
Food and beverage industry
Stabilization ponds in series
Biotechnology Anaerobic
digestion
+sterilization
Stabilization ponds
Coffee production
Stabilization ponds
Chemical and metallurgical industries
Physical-chemical process (equalization, neutralization,
precipitation, flocculation, sedimentation, etc.).
Oil production
Oil -water separation
Deep well injection
Pesticide factories
Evaporation lagoons
Livestock facilities
Anaerobic digestion
Stabilization ponds in series
In general, the situation of the industrial and livestock wastewater treatment systems, regarding
technical conditions, operation, maintenance and performance is similar to that one of the
treatment facilities for domestic wastewater.

Future Directions
Taking into account the country's peculiarities and economic reality, the characteristics of the
major sources of pollution and the current status of technology for wastewater treatment and
disposal, emphasis will be placed on the following actions:
� Adoption of technology suitable for local people and local conditions, specially low-cost
technology.
� Introduction of technologies that provide effluents that meet the quality requirements for
reuse in irrigation, unicellular protein production, aquaculture and other non-potable uses,
particularly in sugar industry and livestock sector.
� Introduction of dry collection methods of solid and semisolid wastes in livestock facilities
and some industries, to avoid or decrease their presence in wastewater discharges.

� Introduction of anaerobic treatment technology followed by a polishing process in some
types of industries and livestock sector, as an appropriate way to reach acceptable
pollutant removal efficiency and obtain biogas to generate energy.
� Gradual introduction of constructed wetlands and aquatic plant treatment systems in
small communities, to assess their performance in Cuba's conditions.
� Achievement of a more efficient and effective functioning and maintenance of the
existing wastewater treatment facilities and progressive rehabilitation of those in
defficient technical and physical conditions.
� Systematic control over the operation and maintenance of the installations.
� Training of personnel in charge of the facilities' management and operation.

Conclusions
The application of environmentally sound technologies for wastewater treatment and disposal is
essential to halt and reverse the effects of the environmental pollution caused by the inadequate
management of domestic, industrial and livestock wastewaters.
At present, the Cuban economy can't by itself cope with the demand for material and financial
resources to maintain and repair the existing infrastructure and significantly increase wastewater
treatment coverage. Consequently, the country requires international cooperation.
Although our country has the potential technical capacity and the social infrastructure to generate
and receive environmentally sound technologies for wastewater treatment and disposal,
organizational and management efforts must be made to overcome the existing shortcomings in
waste management, including the effective implementation of instruments such as the
environmental legislation and standardization, the Environmental Impact Assessment as a tool
for evaluating the technologies to be used in the new development projects, the Environmental
Licensing Process, the State Environmental Inspection and the Scientific and Technological
Innovation.

References
Ministry of Science, Technology and Environment. National Environmental Strategy, 1997.
PHO/WHO. Sectoral Analysis in Water Supply and Sanitation in Cuba. Sectoral Analysis Series
No. 3, 1994.
Center for Environmental Information, Management and Education. National Inventory of Point
Sources of Pollution, 1998.
Acosta R. Clean Technologies: Cuban Experiences. Industry and Environment/UNEP, Vol. 12,
No.1, 1989.

Adopting, Applying and Operating Environmentally Sound
Technologies for Domestic and Industrial Wastewater Treatment
Wastewater Disposal in Haiti
Prof. Carlo Lafond
Directeur General, Ministere de L'Environnenment, 181 Haut Turgeau, P-AU-P, HAITI
Tel: 509-45 0645/45 7585/45 7572, Fax: 509-45 7360/45 1022,
Email: deg.mde@rehred.haiti.net, Email: deg.mde@palaishaiti.net

As way of introducing this topic of Wastewater Disposal in Haiti, we should emphasize that, in
order to choose the appropriate system in a country like Haiti, technical, social as well as
economic or political considerations have to be made:
� Public health considerations have to take into account not only the individual systems of
the private houses, but the public places, like market places, schools.
� Public participation in all phases of the project, design construction and maintenance.
Once the collective contribution of a community is guaranteed, institutional arrangements
have to be setup for the sustainability of the project.
� Environmental quality criteria, taking into consideration the viability and all the possible
impacts of the project on the groundwater and on the air.
� In Haiti, the economic considerations involve the lowest dependence on imported
products like sinks and W.C. toilet bowls, and even the maintenance tools of cleaning
trucks equipped with vacuum pumps.

Wastewater Disposal Systems in Haiti
Basically two possibilities exist as wastewater disposal in Haiti:
� Either the collective disposal through small sewer systems including a primary treatment
plant.
� Or the private disposal system through individual holding tanks, cesspools and septic
tanks.
� Technically speaking, sanitary sewer system by gravity or under pressure would represent
the best available technology for Haiti, and such a system could be used in the brand new
rich suburban neighborhoods.

Two historical cases come to mind:
i. In 1972, a complete system of sanitary sewers, separate from stormwater
sewers, was designed by the American firm called Engineering Science Inc.,
but finally the idea of a separate sanitary sewer system was abandoned.
ii. And, as a matter of fact, a recent upper - middle class community named
BELVIL, meaning PRETTY TOWN -was originally conceived with a
separate sanitary sewer and a small primary treatment plant. Political troubles
of 1991-1994 had forced a change of course, and all the houses were finally
built with Septic Tanks.
But so far, no sanitary sewers had been built in the country because of unreliable water supply or
a practical problem of maintenance cost, the socio-cultural habits of the population that would
require an appropriate environmental education program, the investment costs related to the
construction of such sanitary sewer and treatment systems. The country has a very low water
consumption ratio.
Due to the unavailability or the inadequacy of piped water supply in Haiti, the household
wastewater collection systems are the common practices: which is in accordance UNEP-
CREP'S with Decision Tree for Appropriate Sewage Collection.
However, in the long run, small public or private sanitary sewer systems could be constructed.

Individual Wastewater Disposal Systems in Haiti
PIT Latrines
Construction of latrines with drywalls had been the most used in Haiti. Even in the richest
private houses, it exists latrines in the backyard for the servants. The local technology is well
established. The maintenance process is also well established. Good ventilation exists all year
long. The lifespan of such a holding tank is more than five years for a family of ten people.
These latrines can have the following shapes:
� The simplest kind is one holding tank which is a temporary structure, and could be
ventilated or not. It has a prefabricated cover with a piece of pipe for ventilation. Once it
is full to a height of two-third (2/3), it is generally filled and covered up. The slab is then
removed and transferred to a new location.
� The most advanced type is a double tank, well ventilated. It requires no real maintenance.
It avoids contamination problems and is really affordable by the populations. The major
disadvantage of this system lies in getting the proper sizing of the tank.

� A regular maintenance schedule is necessary with proper dumping of the resulting solid
waste.

Aqua-Privy or Pit Latrine with Impervious Walls
In Haiti, this PIT latrine is used when the groundwater is relatively high: this is what is called in
English aqua-privy.
Even though it functions as a latrine, it is not relying on ground infiltration of liquid wastewater.
The aqua-privy has a performance lower than the septic tank, but it could be integrated later in a
sewer system.

Septic Tank
In Haiti, the septic tanks represent in the towns what the latrines constitute in the rural areas. The
sinks, the toilets and the W.C. are connected into the septic tank.
The tank, with one or two compartments, separates the wastewaster from the sludge. The sludge
compartment can be cleaned every two-year. The liquid is directed in an infiltration well, and
could also be connected eventually to another system for infiltration in the surrounding ground.
In Haiti, many institutions had developed their own septic tank system. An effort is being made
by a public enterprise dealing with social housing. The adopted system had been well tested so
far. Developed into modules called "sanitary blocks", they had been used by housing projects in
Haitian slums. The problems faced by the system are related to sanitary education, ignorance and
maintenance cost for the community.

Construction of Community Sanitary Facilities
� Some Public toilets have been constructed in some areas like the public places, market
places, hospitals and churches.
� Public sanitary facilities are necessary in HAITI, in the neighborhoods with very high
population density like the slum areas of the biggest towns.
� In two slums of Port-au-Prince, namely Cit� Soleil and Drouillard, public showers are
added to the public toilet facilities.

Considerations About Industrial Wastewaters
In Haiti, where the industrial sector is not big, and mostly concentrated in Port-au-Prince, we are
dealing mostly with manufactures, and factories concentrated in industrial parks. Those factories
use regular septic tanks for their waste.

However, some industries, like soap factories, pharmaceutical industries use their own treatment
processes for neutralizing their wastes, before dumping them in the street stormwaters.

Role of the Ministry of Environment (MOE)
� The Ministry of Environment is not yet involved in monitoring the treatment of the
sanitary wastewaters, from private or industrial sources.
� The MOE is considering the introduction and the common use of the W.C. watersavers
using only 1.5 gallons of water instead of the classic 5.0 gallons.
� The MOE is working on specific norms for wastewater pretreatment and treatment, for
domestic and for industrial communities.
� The Environmental Impacts of community housing projects as well as industrial projects
have to be studied, particularly for the groundwater pollution of their liquid wastes.

General Prospects
1. Settling or sedimentation tanks similar to the Imhoff tanks could be used sooner or later in
Haiti.
2. Small separate sanitary sewers with facilities could be tried in some suburban areas with
good water supplies and modern toilet facilities like water closets (W.C.).
3. In Port-au-Prince, portable toilets hare been introduced, whenever there is a big crowd for a
special event, like the yearly Carnival, or a public concert or church event.
4. In some rural areas, aerated lagoons could be tried out.
5. Concerning the industrial wastes, they should be considered on a case-by-case basis.
6. Any new industrial park will take into account the sanitary facilities for the workers as well
as the disposal of any industrial wastes.
7. The role of the Ministry of the Environment will be important as the official institution
dealing with monitoring and establishing norms for groundwater pollution prevention.
8. The MOE should lobby for the future ratification of international convention dealing with
industrial wastewater or with any persistent or non-biodegradable products.
9. In the fight against pollution by wastewater in Haiti, the MOE is studying an interconnection
or symbiosis between some Conventions ratified by Haiti. And, as a National Focal Point, we

are considering an interface of such Conventions, in their relations with wastewater disposal
and treatment.
� Pollution of water resources, by way of the groundwater pollution which is
an objective of the CCD or Convention to Counter Desertification.
� Coastal pollution of the sea, of the coral reef, and the marine species
(Convention upon Biodiversity)
� Pollution by dangerous wastes (covered under the Basel Convention)
� Considering the precarious situation of Wastewater disposal and
Management in Haiti, the Ministry of Environment has been working for
the official signing and ratifying of the Carthagen Convention. In the
meantime, the MOE will participate in the future proceedings of the Wider
Caribbean Region on that subject. The MOE is also showing a strong
interest in the Protocol to Marine Pollution from Land Bused Sources and
Activities (or LBSMP protocol). As a follow-up to the CEP Technical
Report #40 we have improved on the table 2-3 of the report.

Conclusion
As a final word to this presentation, I would like to emphasize that the topic of wastewater
disposal and treatment in Haiti, is part of an overall focus by the Ministry of Environment, on its
way to preparing a National Environmental Action Plan, or NEAP for Haiti.
In fact, one of the themes already covered by a consultant concerns this matter.
Finally a specific Service of the MOE is the Service of Waste Management and Pollution
Control which will be drafting criteria and impact statements norms to prevent and fight against
groundwater pollution by domestic and industrial wastes.
Thank you very much for your patience and your understanding of my deep French accent.
God bless you.

References
USAID: "Manuel Pratique de l'Equipement Rural" (III) INSTALLATIONS SANITAIRES,
Serie Techniques Am�ricaines #104 Centre R�gional d'Editions Techniques (CRET).
"Assainissement des villes de Province: Cap-Ha�tien, Gona�ves, Saint-Marc Rapport B:
Faisabilit�", MSPPP, GKW Consult, Juillet 1990.

Appropriate Technology Sourcebook, Ken Dumond Danaman, 1993, Volunteers in Asia.
Parc Industriel SONAPI, Intermarketing Union Inc., Ig., N.Y., 1996.
MPCE, "Conf�rence Environnement et D�veloppement dans la Cara�be Francophone", 1990.
Texte pr�sent� par le MSPP.
"Appropriate Technology for Sewage Pollution Control in the Wider Caribbean Region, CEP
Technical #40, 1998, UNEP.
Projet de Loi Organique, Minist�re de l'Environnement (MDE), 1998.
"Preliminary Design Study of Sewerage and Stormwater Drainage, for Port-au-Prince and its
environs" Engineering-Science, Inc., October 1972.
"Modules Sanitaires" Entreprise Publique de Promotion des Logements Sociaux, EPPLS, 1998.
Appropriate Technology for Portable Disposable Waste System, Firme JEDCO, Port-au-Prince,
1998.

Wastewater Management In Jamaica
Mrs Ianthe Smith
Senior Director, Pollution Control, Natural Resources Conservation Authority
531/2 Molynes Road, Kingston 10, JAMAICA
Tel: 876-923 5125, Fax: 876-923 5070

1.0 Introduction
This paper will look at the wastewater management systems in Jamaica, the regulatory
framework, the current status of the treatment facilities and the areas in which improvements are
necessary.
Wastewater for the purposes of this paper will refer to sewage and wastewater generated from
industrial activities. The latter will be referred to as trade effluent.

2.0 Main operators of wastewater treatment facilities
There are a number of entities that operate wastewater treatment facilities in Jamaica. Sewage
treatment facilities comprise the largest network of wastewater treatment facilities on the island.
The following table shows a list of the major sewage treatment plant owners and operators. The
National Water Commission (NWC) operates the largest number of plants and has a fairly large
network of sewerage systems in major Cities and towns.
Table 2.1
Owner/operator
Percentage owned
National Water Commission
36
Ministry of Housing
14
Ministry of Education
4
Private developpers
5
Hotels & Resorts
16
Industries
8
Varied owners
17
Source of data: Environmental Control Division Annual Report 1997
Approximately 20% of the population island wide is connected to sewage treatment facilities.
Major urban centres such as Kingston and St. Andrew, St. James and St. Catherine account for
approximately 90% of the waste handled by the NWC.
The NWC will soon commission three new sewage treatment facilities in Ocho Rios, Montego
Bay and Negril. These are tourist locales that have seen rapid growth in population resulting
from migration into the areas. Consequently the infrastructure needs to be upgraded.

The Ministry of Environment and Housing usually operates sewage treatment plants associated
with government housing projects but eventually hands these plants over to the NWC.
Increasingly the NWC has indicated that they must agree to the proposed sewage treatment
facility that they are eventually expected to take over. The NWC has also indicated that they are
discouraging the use of package plants and promoting the use of sewage treatment ponds where
applicable. There is a preference for low technology facilities so that the maintenance costs can
be reduced.
The Ministry of Health operates the sewage treatment plants associated with their hospitals and
health care facilities.
The Urban Development Corporation (UDC) operates a number of small sewage treatment plants
across the island. The areas served by the Negril and Ocho Rios plants are to be covered by the
new sewage treatment facilities being built by the NWC.
Hotels and resorts oftentimes have their own sewage treatment plants but it is expected that
many will tie into the new NWC plants located in Negril, Ocho Rios and Montego Bay.

3.0 The Regulatory Framework
The Natural Resources Conservation Authority (NRCA) has the mandate for environmental
management in Jamaica. The NRCA Act 1991, Section 12, indicates that a licence is needed for
the discharge of wastewater into the environment and also for the alteration, reconstruction and
construction of wastewater treatment facilities.
Effective January 1, 1997, the Permit and Licence regulations were promulgated and required
that a Permit be obtained from the NRCA for the construction and operation of a new wastewater
treatment facility and that a licence be obtained for the discharge of trade and sewage effluent.
The NRCA has been processing permit applications for new wastewater treatment facilities and
licence applications for the discharge of effluent. The following table gives a breakdown of the
number of permits granted for sewage and industrial wastewater treatment facilities and the
number of licences granted for sewage and trade effluent discharge since the start of the permit
and licence system in January 1997.
Table 3.1
Type of permit/licence granted
Number
Wastewater plant - permit
3
Sewage plant - permit
12
Trade effluent licence
9
Sewage effluent licence
14

The NRCA has established standards for sewage and trade effluent quality and meeting the
standards is a condition of every licence granted. (See Appendix 1 for the trade and sewage
effluent standards). It should be noted that there are two standards for sewage effluent, standards
for existing facilities and those for new facilities. Currently permits and licences are only being
granted for new facilities, existing being defined as those facilities that had all their statutory
approvals in place prior to January 1, 1997.
The conditions of the licence usually require that there is self monitoring on a specified
frequency to ensure that standards are being met. An Environmental Monitoring and
Management Plan is usually requested of the entity that has been granted the Licence. The
NRCA conducts post approval compliance monitoring to ensure that conditions are being met.
Samples of effluent are also analysed by the NRCA laboratory.
Standard conditions included in sewage treatment facility permits and licences include the need
for standby generators and standby pumps where there are mechanical plants. Also contingency
plans in the case of malfunction of the plant must be lodged with the NRCA.
The regulations for the trade and sewage effluent standards are currently being prepared and it is
expected that they will be finalised by March 1999. The NRCA will then be in a position to
licence existing wastewater treatment facilities. There will also be regulations for waste
discharge fees, which in principle will require the entity discharging effluent to pay a flat rate fee
for that discharge once the effluent is in compliance with the NRCAs effluent standards.
However if the effluent is out of compliance, an additional punitive fee will be imposed
increasing geometrically for each day the effluent remains out of compliance. The aim is to
encourage the polluter to fix the problem rather than to pay the penalty.

4.0 Current status of Wastewater Treatment Facilities
4.1 Section 17 Programme
The NRCA has already been working with some of the existing major generators of effluent
through the Section 17 Programme. The Programme initially targeted those entities that
discharged wastewater into the Kingston Harbour but has since expanded to include all sugar
factories and distilleries, the bauxite/alumina plants, the coffee pulperies as well as other
establishments known to generate sewage and trade effluent.
Under the Programme the NRCA gets information by way of a questionnaire every four months
on the pollution control and waste management practices of the entity. Effluent quality is one of
the areas reported on. Verification monitoring is done by the NRCA to ensure that the data
provided is indeed accurate. It is expected that these entities will eventually be incorporated into
the licencing system for existing entities that is expected to start in the 1999/2000 fiscal year.
Since the inception of the Section 17 programme in 1993, the NRCA has issued 213 notices to
industries and has conducted verification monitoring visits to approximately 70 % of the

industries. Based on the reports submitted and the visits done, it is clear that there is still a lot of
work to be done. More than 90% of the entities with an effluent discharge do not consistently
meet the standards. There has been some improvement in the quality of the effluent and about
30% are making serious efforts to achieve compliance.

4.2 Trade and Sewage Effluent Quality
The sewage effluent quality from the NWC sewage treatment facilities are inconsistent and more
than 85% of the 48 plants do not meet the sewage effluent standards. The NWC is still to present
the NRCA with a strategic plan on how they intend to bring their existing plants into compliance
with the standards.
The NWC is about to commission three new sewage treatment plants in Negril, Ocho Rios and
Montego Bay. These plants have been plagued with a number of problems during the
construction phase that has resulted in lengthy delays. It is expected that the plants will be
commissioned by December 1998.
However there still exists the problem of interconnection to the sewerage system by those
entities that generate wastewater. This presents a challenge to the NWC as there is no legislation
binding the wastewater generator to interconnect to the sewerage system. The sewage treatment
plants will not realise their true purpose if there are insufficient connections to the sewerage
system.
Industrial wastewater treatment facilities in the agro-industrial sector have been plagued with
poor trade effluent discharge quality. This is of particular concern in the sugar industry, coffee
industry, distilleries, and abattoirs. Wastewater tends to have high Biochemical Oxygen Demand
(BOD), Total suspended and dissolved solids. End of pipe treatment options tend to be looked at
as the first solution to the problems, however the NRCA has been encouraging waste generators
to look at waste minimization and cleaner production as alternative solutions which usually end
up saving scarce financial resources as water and energy consumption are reduced.
The bauxite industry has been known to have problems with trade effluent that has a high sodium
content. The power generation sector has problems with the temperature of their effluent
discharge and the management of oily wastes.
It is expected that many industries will wait until the legislation to licence the effluent discharge
from existing entities is in place before they get their house in order. Those that have responded
to the NRCA's advice to get started with their plan to achieve compliance will be ahead of the
game.
Where there are genuine cases of difficulty in achieving compliance, the NRCA will deal with
these on a case by case basis. We realise that changes cannot take place overnight but we expect
a plan of action to be submitted to the NRCA so that we can monitor the progress being made.

4.3 The CWIP Project
There is the Coastal Water Quality Improvement Project (CWIP) a USAID funded project
undertaken in collaboration with the NRCA, that has been working with the NWC to help them
define their plans on how they will address Operation and Maintenance issues pertaining to their
sewage treatment plants.
The CWIP project has been assisting the NWC to explore the options of Public/Private
partnerships for operating the plants and has conducted a Training Needs Assessment for the
operators of the plants. It is expected that the assistance provided by this project will help the
NWC tackle some of the long-standing problems associated with the operation and maintenance
of their plants.

5.0 The
Future
The NRCA will continue to work with waste generators to address the problem of poor quality
effluent discharge so that the rivers, marine environment and the land will not be degraded. This
can only be achieved through a partnership arrangement between the waste generators and the
NRCA.
The licencing system for new and existing entities and the waste discharge fees will provide the
regulatory regime for wastewater management. The NRCA realises that incentives need to be
provided as well and is actively looking at ways in which we can also provide the carrot and not
just use the stick.

Mexico
Dr Felipe Arreguin Cortes
Tratamiento y Calidad de Agua, Instituto Mexicano de Techologia del Agua (IMTA)
Paseo Cuauhuahuac 8532, Jiutepec, Morelos, C.P. 62550, MEXICO
Tel: 52-73-194381, Tel: 52-73-194000 ext. 543, Fax: 52-73-194381, Email: arreguin@tlaloc.imta.mx

1.0 Water in Mexico
The almost two million square kilometer surface area comprised by Mexico has an average
annual rainfall of 777 millimeters, equivalent to 1522 cubic kilometers. However, the spatial
distribution is quite irregular. Approximately 42% of the country, mainly to the north, receives
an average annual rainfall of less than 500 millimeters and in some cases, near the Colorado
River, less than 50 millimeters. On the other extreme, 7% of the nation has an average annual
rainfall above 2000 millimeters, with localized regions where more than 5000 millimeters of rain
reach the ground. In general, 80% of the rain occurs during the summer months.
Of the water that falls on Mexico, 27% is transformed into surface runoff that is 410 cubic
kilometers is concentrated in 314 basins. The distribution here is irregular as well. One half of
the runoff is localized to the southeast, area that geographically is 20% of the nation, while only
4% is found in the northern region, which is about 30% of the territorial extension.
The storage capacity of Mexican lakes and lagoons, some 14 cubic kilometers, and dams,
another 189 cubic kilometers, account for 47% of the average annual runoff.
Of the rain that infiltrates, 48 cubic kilometers renews the aquifers. In the irrigated areas,
aquifers receive an artificial recharge of an additional 15 cubic kilometers. Finally, there are
estimates that 110 cubic kilometers of the water in aquifers can be used only once.
The availability of water per person is also extremely variable across the nation. There are
regions with 200 cubic meters available for each person, and others with 33 000. On the average,
each inhabitant can use 5 200 cubic meters each year.

2.0 Water
Use
In 1997, the population in Mexico reached 94.3 million of which 13.4 million did not have
drinking water in their homes and 26 million did not have access to sewerage service. This
deficiency was more marked in rural areas. It has been estimated that 8.5 cubic kilometers of
water are extracted to cover the domestic demand. Some 95% of the water supplied to the
communities is disinfected and 2.2 cubic kilometers is potabilized each year.
Mexicans crop 20 million hectares of which 6.2 receive irrigation water. The remainder use dry
farming alone or with technological improvements. In 1994, 61.2 cubic kilometers of water was
extracted for this purpose: 41.1 from surface sites and 20.1 from groundwater sources.

Industries located in suburban and rural areas used 2.5 cubic kilometres of water, while thermo-
and hydroelectric plants required 113.5 in 1997.

3.0 Water Pollution In Mexico
Based on quality assessment studies carried out in 218 basins that cover 77% of the nation and
that account for some 93% of the population, 72% of the industrial production and 98% of the
irrigated land, 20 of the basins were responsible for 89% of the total pollutant load, as measured
by the biochemical oxygen demand (BOD). Four basins receive 50% of all wastewater
discharged.
The most polluted aquifers are underlying great cities and the agricultural areas. These last are
affected by the leaching of the agrochemicals in use.
Deforestation has also contributed to the degradation of the water quality in the nation's basins.
Of the 315 municipal drinking water treatment plants, the 260 on line treated 74,423 lps. From
the inflow of water and community activities, 184,000 lps of wastewater were generated. The
installed capacity for the treatment of these municipal wastewater discharges is 61,653 lps in 821
plants; in fact, only 639 (77%) of the plants were operating and treated 39,389 lps. The nation's
industries generate 82,000 lps of wastewater with varied compositions and characteristics. Most
of the wastes are highly polluting if left untreated. The largest sources of wastewater are in the
areas of sugar refining, chemistry, cellulose and paper, petroleum, soft drinks, textiles, iron
works and food preparation.

4.0 National
Water
Commission
The National Water Commission (CNA), is the water authority in Mexico, was created in 1989.
As a promoter of change, the CNA must become fully involved in the evolution of an
administration capable of fulfilling the demands made on it through the decentralization of
routine processes, the delegation of authority and responsibility to local officials, the creation of
a realistic rate scale for water services and the development of regulations and a new water
culture.
To face these challenges in Mexico, the CNA developed its Hydraulic Program 1995-2000, with
a view to reducing the underdevelopment and limitations in water availability, advancing the
integral reclamation of basins, assuring equality of usage under the law, contributing to the
sustainable development of the nation and expanding society's participation in the planning and
use of water. Outstanding within the Mexican Hydraulic Program is the Water Management
Modernization Plan designed to provide cutting-edge technology to the water sector.

5.0 The Mexican Institute Of Water Technology (IMTA)
The Institute was created in 1986, and its mission is:
"Carrying out research, development, adaptation and transfer of technology, rendering of
technological services and preparing qualified human resources, to administer, conserve and
rehabilitate water to contribute to the sustainable development of the country."

5.1 Water Treatment and Quality
The IMTA has six Divisions, one of them is the Water Treatment and Quality Division. This
Division comprises four areas that specialize in the conservation of water quality, environmental
impact assessments, drinking water treatment and wastewater treatment and recycling with
research in analytical chemistry, microbiology, environmental impact, hydrobiology, industrial
wastewater treatment, municipal wastewater treatment, drinking water treatment and quality
control.

5.2V Mission
Carry out research to adapt, develop and transfer technology for the improvement and
conservation of water quality and the related natural resources, to achieve sustainable
environmental development.
This Division has four areas, that will be described:
Drinking water treatment area
It studies of the characteristics of drinking water sources in Mexico, and the feasibility, operating
conditions and efficiency of technology applied to drinking water treatment plants. The projects
are proposed in accordance with the needs of the nation. Most research is centered on the
application of feasible and economical methods to treat water from natural sources.
Water Quality Area
It makes diagnosis, evaluation and propose solutions of water-related problems in the field of
analytical chemistry, environmental microbiology and hydrogeochemistry.
Hydrobiology and environmental assessment area
It studies the aquatic ecology of fish, invertebrates, plants and weeds in streams and lakes. These
streams are also used to evaluate the impact of industrial discharges and pesticides, and the
effects of impoundments and modifications in the natural flow regimens on invertebrates and
fish. The biological response is also used to assess the impact of environmental stresses on river

biota. The studies are carried out by multidisciplinary teams of hydrologists, chemists, botanists
and zoologists.
Wastewater treatment area
This area develop computer programs for the design of wastewater treatment plants and
sewerage networks. Mathematical modeling of treatment systems and simulations of unitary
processes. Laboratory-scale conventional and advanced treatment tests and large-scale
sedimentation, jar, chemical oxidation, adsorption, microorganism adaptation, biochemical
behavior and specific sludge resistance tests. Evaluation of unitary process efficiency in the
removal of pollutants from wastewater and other specific methods. Definition of adequate
treatment sequences and design parameters, depending on the required effluent quality for reuse
or discharge to a receiving body.

6.0 Cutting Edge Technology or Adequate Technology
Basic treatment methods and technology can be divided in two large groups: simple or
appropriate, and innovative or sophisticated. The title simple does not imply a low efficiency but
that may require plants with reduced energy consumption and uncomplicated technology for
construction and operation, and that may use systems based on natural transformations, such as
stabilization ponds and soil infiltration systems or, finally, the use of aquatic plants and systems,
commonly known as wetlands.
The concept of innovation is the opposite of this, in the sense that the treatment systems are
complicated in the construction materials required, the equipment used and the controls needed,
and much more costly. There are several classes of innovative technological concepts, based on
mechanical and biological schemes, mechanical and chemical schemes, and mechanical,
biological and chemical schemes. These systems usually require highly trained operators and
large investments in operation and construction.
The concept of the Best Available Technology Economically Available (BATEA) should be
adopted in our countries. It is a made-to-order measure that satisfies the specific needs for each
case, each site and each type of wastewater.
Conceptually, BATEA means:
� Prevent the discharge of priority pollutants to the environment or when this was not
possible, reduce their discharge to a minimum and transform them to innocuous
compounds.
� Transform pollutants that may be harmful when discharged in the environment, such as
oxygen consuming products that, as such, are non-toxic.
� Reduce environmental pollution as a whole, by adopting the Best Available Technology
Economically Available for the substances to be discharged.

In practical terms, BATEA for the treatment of wastewater implies
� Elimination of priority pollutants when possible through the selection of raw materials,
modifications in the processes or use and adoption of clean technology.
� Prevention of the dilution of polluting discharges.
� Measurement and constant monitoring of effluents and pollutants.
� Separation of discharges containing priority pollutants for individual treatment.
� Recovery of materials for reuse, when possible.

7.0 Final
Considerations
Sustainable development is understood as the administration and conservation of natural
resources and the focussing of technological and institutional change to assure the continued
satisfaction of human needs for current and future generations. This sustainable development
conserves land, water, plant and animal genetic reserves, does not degrade the environment and
is technically appropriate, economically feasible and socially acceptable (FAO).
In this context, human beings and the capacity of the ecosystems to maintain life are at the
center. In the area of ecologically sustainable development, the existence of extreme poverty and
the degradation and pollution of the ecosystems are basic concerns that should be surmounted.
For most industries, the production, control and disposal of wastewater has become an integral
part of the production strategy and costs. As the cost of treating and disposing of wastes
increases, more sophisticated treatment becomes feasible. However, the basic, simple methods
should not be forgotten - policies to minimize the generation of wastewater, reduce water
consumption and decrease the requirements of treatment processes. Minimization should be a
prime consideration in any pollution control strategy and treatment philosophy.
All human beings, institutions, organizations and countries that seek to live in harmony with
their environment should have, as environmental and ecological goals:
� Reduce and, ideally, eliminate, pollution at its source,
� prevent the accumulation of non-degradable toxic substances,
� reuse water and other materials,
� prevent the transport of pollutants,
� avoid the exhaustion of natural resources,
� administer energy consumption,
� develop and use non-polluting energy sources,
� minimize desertification, and
� prevent water-bourne diseases.

The ecological perspective starts with a global vision and an understanding of how the different
components of nature (including the human being) interact through patterns that tend toward
equilibrium and that persist through time. The need to move toward sustainable development
requires a change in the general paradigm towards an ecological focus, a dynamic environmental
education based on these concepts, and sustained support of the research activities, basic and
applied, that will give forth the technological development activities needed by humanity.

Wastewater Collection and Treatment Technologies in the Netherlands
Antilles
Rodriguez, Arthur A. B.Sc., Ing. Oleana, Patricio D., Department of Public Works
Cura�ao, Netherlands Antilles
Department of Public Works (DOW), Subdivision Sanitary Engineering, Head Process Engineering
Landhuis Parera, PO 3227, CURACAO, N. A.
Tel/Fax: (599-9) 868-6866, Tel: (599-9) 433-4444 (Head Office)
Fax: (599-9) 461-7969 (Head Office), E-mail: curzuiv@cura.net

The Netherlands Antilles is part of the Kingdom of the Netherlands and consists of five islands:

Island Population
(inhabitants)
Windward Islands
Saba 1.300

Saint Eustatius
2.300

Saint Maarten
35.000
Leeward Islands
Bonaire 15.000

Curacao
150.000

Saba and Saint Eustatius
Because of their scale, wastewater management has not been an issue as yet.

Saint Maarten
The infrastructure did not keep track with the rapid increase of the population and tourism. In
Sint Maarten a small "Trickling filter" filled with synthetic material, primary sedimentation and a
settling tank is in use. An expansion of the sewerage and an upgrade/expansion of the treatment
plant are now been planned.

Bonaire
Bonaire's main income derives from the diving tourism. The nutrient pollution originating from
direct or indirect sewage discharges is the main threat for this natural resource. Bonaire has an
attractive marine environment, especially for divers. They support some of the best remaining
coral reefs in the Caribbean. The reefs are internationally acclaimed for their outstanding natural

beauty and their high diversity as well as the richness of fishes and other species that live near
the reefs. Bonaire is now in the stage of developing a plan to collect, transport and treat sewage.
In the first phase of the project the coastal areas have the highest priority. The effluent will be re-
used for agricultural, horticultural and landscaping purposes. The European Union and the
Netherlands will finance the project.

Curacao
In Curacao the Department of Public Works (DOW) is in charge of wastewater management.
The environmental management system is in accordance with international standards. DOW is in
charge of the planning by developing mid and long-term plans, as well as recommendations on
investment plans and financial requirements. A Wastewater Master Plan has been developed.
The objective of the Wastewater Policy is:
In order to prevent nuisance, health and environmental hazards, sewage collection and treatment
is recommended, taking into account the social, economic and financial limitations. The effluents
of the treatment plants should be qualitatively adequate for reuse in agriculture, horticulture and
landscaping.
The technical, legal, institutional and financial aspects of wastewater management have been
outline in this document. The planning period is 1990 � 2005.

Sewerage:
The sewerage is a combination of gravity (263 km � 82%) and pressurized (54 km � 18%)
sewers and pump stations.
In the inner city, public-housing areas, highly populated areas, and areas with a high
groundwater level, sewerage has been constructed.
Department of Public Works is now working on standardization of sewers, and (under ground)
pump stations in order to keep the maintenance simple and the stock of spare parts limited.

Components:
� Control vale (for automatic control of a bi-directional sewer managing)
� Buffer stock (to avoid dumping by a calamity)
� Bar screen of 10 cm
� One mixer (to homogenize the wastewater, which prevents sedimentation and floating
material)
� Tow wet submersible pumps
� Dry arrangement of the moving parts (check valve, valve, pressure gauge, pH and EC)
� Compost filter (to prevent unpleasant odor)

� Soft start / stop (in order to prevent broken pipelines by increase of the sudden pressure)
� Telemetric system (so the pump station can also be managed by remote control and to get
management information at any time
� Telephone communication

Four Sewage Treatment Plants (STP):
In Curacao we have four treatment plants.

STP � Tera Cora (1984):
This is a small STP in an urban area; with a load capacity of 4000 population equivalents (p.e.)
and a daily flow of 300 m3/d; trickling filter filled with synthetic material, combined with an
Imhoff tank and maturation ponds.

The Slaughterhouse STP (1988):
The load capacity is 2700 p.e. and a flow of 65 m3/d; trickling filter with forced air down stream,
combined with an Imhoff tank, and a settling tank; discharges into a bay.
The main Sewer Treatment Plants of Curacao are Klein Hofje and Klein Kwartier. The influent
of Klein Hofje and Klein Kwartier consists of domestic and some industrial sewage and storm
water of the inner city. Household sewage that has been collected by trucks (septic tanks or
cesspits) can be discharged at the STP, unless the pH and conductivity (EC) are between limits.
In general, industrial sewage will not be accepted, because of possible presence of toxic
components. Exceptions are possible.
The control of the water and sludge quality is being executed in a laboratory.
The effluent should be of a certain quality in order to prevent health hazards or damage of crops
and landscaping. The re-use of the effluent is restricted.

STP � Klein Hofje (1986):
Type: Trickling filter with 950m3 synthetic material and 3000m3/h forced air down stream.

Design Parameters:
Pollutions Load
(p.e.)
40.000

Daily Flow Rate
(m3/d) 2.300 (3500)
Hydraulic Peak (m3/h) 230

Flow
Maximum Peak (m3/h) 350

Flow
BOD (g/p.e./d)
50
(7)
TKN
(g N/p.e./d)
10

Suspended Solids
(g/p.e./d)
60

BOD Load
(kg/d)
200

TKN Load
(kg/d)
400

Suspended Solids
(kg/d)
2400

The trickling filter has been designed for a hydraulic flow of 2300 m3/d and a pollution load of
50g BPD/p.e./d. The ratio between load and flow is not as designed. The STP receives a
pollution load of only 7g BOD/p.e./d. Part of the pollution stays in the sewers or pumping
houses. The hygienic efficiency of the maturation ponds is the limited factor, while the hydraulic
flow can be increased till 3500 m3/d without further expansion.
Components:
Water Line: Gully Emptier discharge pit
Bar rack (mechanically cleaned rake) 15 mm
Screening press
Influent pump station (2 x 200 m3/h)
Primary sedimentation, Dortmundtank (4 x 12.5 m3/h)
Trickling filter (synthetic material)
Forced air (ventilator with extractor fan, 3000 m3/h)
Settling tank, Miedertank (2 x 20 m3/h)
Effluent quantity measurement, ultra sonic
Maturation ponds (7 x pc. � 19.000m2 & 28.500m3)
Effluent pump station in combination with buffer capacity (2 x 250 m3/h)
Fully automatic effluent back flushing filters, slot type candles, pore 75 pm
Effluent storage tank (4071m3)
Effluent distribution system (pump station � 3 to 4 bar)

Sludge Line: Grit chamber/washer (10 � 20 m3/m2 h)
Gravity sludge thickener (20 m3 /h)
Anaerobic sludge digestion (1040m3 � 32 C � circulation by pumping 20m3/h)
Electrical heating element (10 x 1.8 kW) in thermal oil
Gas compressor (220 m3 /h for mixing the contents of the digester)
Gas holder (100 m3)
Final sludge thickener (20 m3 /h)
Drying beds with drain system (1600 m2)
Sludge storage (280 m2)
Gas engine and generator (electricity 80 kW � 900 m3 CH4/d)
Treatment Results:

Effluent
Efficiency
BOD (mg/l)
31
80% after
polishing
COD (mg/l)
117
68

COD/BOD
2.19

NH4
(mg/l) 19

TKN (mg/l)
28
56

Ptot
(mg/l) 32
11

NO2
(mg/l) 2.6

NO3
(mg/l) 4.3

Suspended
(kg/d) n.d.

Solids
Fecal
(cfu/100ml) 1012

Coliforms

STP � Klein Kwartier (1983):
Type: Oxidation ditch activated sludge (a small oxidation ditch, 4000 p.e. / 160 m3/d, is being
expanded with 31.000 p.e.; this is that first phase expansion).

Design Parameters:
Pollutions Load
(p.e.)
31.000
Daily Flow
(m3/d) 2.500
Hydraulic Flow
(m3/h) 250
BOD (g/p.e./d)
35
Sludge Load
(kg BOD/ kg SS/d)
0.07
Sludge
(kg SS/m3) 4
Concentration
OC/Load (kg
02/kg
BOD) 3.0
Sludge Volume
(ml/g) 100
Index
Oxygen Demand
(kg 02/h)
136
Components:
Water Line: Gully Emptier Discharge Pit (which is automatically controlled)
Step Screen (automatic on level control 340 m3/h) 5 mm
Screening press (automatically controlled)
Grit chamber (349 m3/h)
Grit washer (15 m3/h)
Grease separator (17 m3 � t+5 min.)
Oxidation ditch Activated-Sludge (3875 m3 � 390 m3/h)
Mechanical aerator (horizontal axis type) 4 x (5.5 * 0.87m) 34 kg 02/h
Settling tank (418 m3 � 209 m3/h)
Return sludge 105 m3/h
Effluent quantity measurement (ultra sonic � max. 334 m3/h)
Ground infiltration (3 x infiltration pounds � 265 m3/h)
Effluent distribution (deep well pumps 5 x 10 m3/h � effluent 50 m3/h)

Sludge line: Sludge thickener (20 m3/h)
Drying fields / drainage system (1600 m2)
Management:
The following aspects are part of the management:
Development plans � institutional development � quality assurance systems � research and
inspection.

All our personnel should have electrical, mechanical and process control backgrounds (EMP-
man). To achieve this they will be trained in the Netherlands.
� The sewerage Treatment Plant Klein Kwartier will be fully automated and can be
managed by remote control. In case of calamities automatically alternative sewage routes
or discharges are being activated.
� The daily management will be based on: Suspended Solids (ss = 4 gl) � Sludge Volume �
Sludge Volume Index (SV1 = 100 ml/g) � BOD load (kg BOD/m3d) � Hydraulic load
(m3/m3d) � Aerated time (V/Qd = 2.5/3 d) � Oxygen concentration (mg/l) � Sludge age
(20/30 d) � Denitrification � Effluent quality (10 mg BOD/l � Fecal coli)

The Problems and the Solutions
You are welcome to share any alternative or additional solution you may have.
1. Gravity and Pressurized Sewers:
� Because the landscape is very hilly, frequently broken pressurized
pipelines occur due to hammer stroke.
To resolve this problem we have decided to introduce a soft starter with option soft stop at the
pump stations.
� As a result of overdue maintenance of the gravity sewers, the pipelines
became overloaded by sedimentation.
We have acquired a gully emptier/sewer cleaner to do the preventive maintenance. For the
pressurized sewer we keep the velocity as designed 1.6 m/sec.
� Public awareness is very important for depositing their garbage in the
sewers or pits.
The government is working on a structural plan of awareness.
2. Pump Stations (36) with Wet Submersible Pump:
� Different wet compartments of the pump stations are heavily corroded by
the high concentration of H2S produced by putrefaction.
First action is to prevent the sedimentation, which means elimination of the anaerobic process.
The pipelines are covered with fiberglass, and all moving parts are arranged in a dry
compartment.
To prevent sedimentation we have installed a mixer (submersible pump without pump-house) to
homogenize the sewage before transport.

� To prevent unpleasant odor in highly populated areas all pump stations are
provided with:
A compost filter which works with forced air.
3. Sewage Treatment Plants:
The treatment efficiency of the STP-Klein Hofje is insufficient due to:
� The total Suspended Solids (TSS) of the influent which is very low;
� Algae growth in the maturation ponds which means BOD increase;
� Limited absorption of UV-radiation (algae), which has a negative effect on
the hygienic quality.
� To get a higher pollution load at Klein Hofje, all pump stations will be
provided with a mixer.
� Enzyme will be dosed in the trickling filter to get a better purification
efficiency.
� Propeller aerator to reduce or eliminate the algae growth in the maturation
ponds will be installed.
� The bacterial quality is insufficient, because the retention time in the
maturation ponds is too short. The use of an activated carbon filter and
UV-disinfecting as tertiary treatment is being studied at this moment.
� To eliminate (stripping) the H2S production in the anaerobic digester,
FeCl3 is dosed into the sludge digester.
� We use a computerized maintenance system, which gives monthly
information.
All parts must be imported, so stock management is very important.

Waste Water Management � St Kitts
Errol A Rawlins
Deputy Chief Environmental Health Officer

St Kitts is a relatively small island approximately 164 square kilometres with a population of
estimated as of June 1997 � 33,500.
The island is approximately 37 km long and 5 km wide at its widest point and is dominated by a
mountain range with tropical forests. Cultivated fertile valleys closer to the coast support
agricultural production.
The water supply of St Kitts consists of surface and sub-surface or ground water.
Despite the comparatively small area and population, the island has a comparatively large and
diverse quantity of industrial activities such as sugar, distillery, brewery, textile, electronics,
fabrication and food processing to name a few.
Like other Caribbean countries the increased supply of potable water, the growing standard of
living and increased industrialization including tourism has resulted in an increase of waste water
to be disposed of.
The most widely used system of sewage disposal is the septic tank and soakaway. The island has
no central sewage collection, treatment and disposal facilities.
There are at least six (6) package treatment plants on the island. There are three (3) Extended
Aeration Plants, one (1) Rotating Biological Contactor, one (1) Leach Field System and one (1)
Activated Sludge Process.
Two of the extended aeration plants are situated at hotels while one is situated at the main
hospital. The Rotating Biological Contactor is situated at a housing project in the capital city.
Approximately eighty-two (82) percent of occupied premises utilizes the septic tank and
soakaway system. The pit privy is also being utilized by a cross section of the general
population.
Sources of wastewater include domestic, industrial, and commercial.
Domestic wastewater is either disposed of into septic tanks, soakaways or channeled to public
drains which ends into the marine coastline.
Liquid waste produce from some industries either enter into soakaways or drains which enter the
coastline.
Wastewater entering the marine coastline is likely to impact on the marine ecosystems.

The operational status of most of the package treatment plants are questionable due to the lack of
proper maintenance and trained personnel. Effluent from some of these plants enters the marine
environment.
The coastal waters of the Basseterre Harbour, Lime Kiln Bay and Frigate Bay are monitored on a
monthly basis for faecal coliform and other physical parameters. There are eight (8) sampling
points in the Basseterre Harbour, two (2) sampling points in Lime Kiln Bay and five (5)
sampling points in Frigate Bay.
The installation of a central sewage collection system for Basseterre is the only practical solution
to the liquid waste problems being experienced.
The connection between poor liquid waste disposal practices and adverse effects on health is
well known, but there is lack of data specific to St Kitts linking current public health impacts.
The Environmental Health Department continues to collect data on the coastal pollution
monitoring programme.
The Public Health Act #20 of 1969 gives the Minister of Health the authority to make regulations
with respect to waste water and its disposal.
The National Conservation and Environment Protection Act #5 of 1987, gives some measure of
protection to the marine environment.

Wastewater Treatment in St. Vincent & The Grenadines
Brian George
Central Water and Sewerage Authority

Introduction
St. Vincent and the Grenadines (SVG) presently has a population of approximately 120,000
persons with the capital, Kingstown, having a resident population of about 15,000 to 16,000
people. Environmental issues affecting health and preventing further degradation of the
environment are becoming focal points of attention, as illustrated by the implementation of the
OECS Solid Waste project, and the studies for the sewerage treatment project.
Predominantly throughout St. Vincent and the Grenadines, sewage treatment consists of septic
tanks for collection and treatment and soakaway systems for disposal of effluent. This applies to
both domestic households and commercial premises such as hotels, etc. As such, sewered areas
are basically areas of central Kingstown and a small area in Arnos Vale, not too far from the
capital.
The two major areas of focus in SVG as related to sewage treatment is the area of central
Kingstown and its surrounding environs, and the South Coast area of the island which is an
extremely densely populated area with several hotels and beaches all in the same locality. The
latter is of great concern due to the political and economic thrust to greater developed tourism.
The Kingstown area has quantities of waste generated from the several restaurants and other food
establishments as would be expected with any other capital city, however, the majority is
domestic sewage. Hence, industrial waste is not a concern eliminating the threat of heavy metals.
With these factors in mind the Central Water and Sewerage Authority of SVG under took to
create a project to address wastewater treatment. As a result, extensive feasibility studies were
done to ascertain and focus on key issues of such a project. The justification for the project was
derived from the fact that reduced pollution and improved health conditions can be achieved
from the implementation of a sewage treatment project. As well as protecting health internally
the outward affects of pollution on tourism are eliminated thus helping the economic
development of the country.
The focus of this paper is the sewerage and treatment systems for the Kingstown and South
Coast areas, the technologies presently implemented and proposed for future development, and
the environmental implications and rational behind certain decisions.

Present Methods of Wastewater Treatment and Disposal
Kingstown
As discussed previously, only the central Kingstown area is sewered. The system consists of 5.8
km of PVC sewers ranging in size from 150 mm (6") to 600 mm (24"). The system was
constructed in the early 1970's with provision for future extension to serve an expanded area and
other parts at a later date. All sewers feed to a collection tank on the sea front, having a capacity
of 54,000 gals. The collection facility is in fair to poor condition and requires extensive
refurbishment.
Collected sewage is disposed via marine disposal, with sewage being pumped out to sea through
a 400 mm PVC outfall. This outfall is approximately 1500m (4800 ft) long and is supposed to
discharge sewage outside of the Kingstown bay locality and into the sea currents where it does
not pose a threat to marine coastal life and man. However, the outfall is in very poor condition
and has several cracks and breaks along its length. Hence, sewage is pumped into the sea much
closer to the coastline than originally intended, only 300m (100 ft) off the nearest bay.
Collection and disposal aside, collected sewage is not treated in any manner. Even the
comminutor which was at the inlet of the collection tank has not functioned for a long time now
and the by-pass arrangement has had to be utilized permanently. This consists of a large grill that
is difficult to clean and regularly blocks.
Recent studies have shown that due to the depth of the outfall at the location of the break and the
quantity and duration of the sewage pumping regime, environmental impacts to date have been
minimal. This is due mainly to the high dilution factor which is achieved on discharge of the
sewage, and the distance of the break from the shoreline is luckily adequate. Usual signs of
negative environmental impacts are minimal, e.g. there are very few signs of non biodegradable
deposits on Edinboro beach (nearest coastline) and bathing water standards are marginally
acceptable as compared to European and EPA standards. Marine life also still appears to be
thriving in this area.

South Coast
The south coast is separated from the capital Kingstown by the highlands of Cane Garden,
having an elevation of approximately 330 ft. Along this coastline, there are a number of beaches
bounded by hotels, and the area is also densely populated. Many of these hotels make an attempt
to have some form of septic tank and soakaway system but this is problematic due to the
proximity to the coastline and resultant high water table level. Instances arise whereby sewage
from seepage discharges straight to sea and, in all cases, sullage (grey water) from kitchens and
bathrooms is discharged straight to sea through stormwater drains. The result is an extremely
heavily stressed environment in this area. Practically all corals have died and bathing water
standards are of critical concern. It should also be remembered that the absence of corals negates
from nature the ability to regenerate its beaches with sand, which is a concern when one
considers tourism.

Options of Technologies/Design Proposals
It is vividly obvious that the present state of affairs must be corrected. In Kingstown it is
imperative that collected sewage undergoes some form of treatment prior to discharge as marine
disposal is still considered to be the most feasible practical option, as re-use needs are limited
and conveyance to the point of reuse is an issue.
The present Kingstown site combined with the reclaimed lands immediately next to it is still a
relatively small parcel of land. Hence, land space is an issue, odour nuisances from treatment is
also a key issue as the site is centrally located in an extremely commercialised area. It is also
evident that the South Coast area must be sewered, resulting in a need to treat the sewage which
is collected in this area.
The recent study findings recommend that presently and for several years to come, preliminary
treatment only shall be required for sewage treatment. The rationale behind such a
recommendation derives its basis from the fact that many treatment processes were developed to
produce safe effluent discharges to rivers and enclosed water courses. It is also considered safe
practice to give little if any treatment to discharge made to the open sea. Once discharges are not
excessively large, the sea is considered to have sufficient self-purifying capacity especially when
combined with suitably favorable sea currents. The latter has been proven by extensive recent
investigations such as drogue tracking and dye tests. However, due to public awareness and
political reasons, this thinking has changed in recent years and there has been increasing
legislation to mitigate against sewage discharge to sea without minimal treatment whether
justified or otherwise on a scientific or biological basis.
It has then been decided to adopt only preliminary treatment for the next 10 years or so, and then
at some later date necessitated by possible implemented legislation and environmental conditions
further treatment shall be constructed. However, with limited land space available, it is difficult
to incorporate and hold secondary treatment at the Kingstown site. As an alternative, there is a
parcel of land on the South Coast at Arnos Vale which is presently a dump site, but is soon due
to be closed. It is therefore proposed to construct a treatment plant at that location. Not only is
more (?) land available but odour would not be such a nuisance.
Bearing these factors in mind, it is proposed to make provision for preliminary treatment for both
Kingstown and South Coast flows in Kingstown for a period of the next 10 years. In this
scenario, a force main would be installed to take the flows from the South Coast over and
through the highland area of Cane Garden and into Kingstown. The proposal is to refurbish the
Kingstown sewage collection facility by installing self- cleaning screens with provisions for
washing screenings making them suitable for transportation. The facility shall be enclosed for
odour control utilizing a biological filter formed from local coconut fiber.
In the future when it may become necessary to have further treatment, it is proposed to construct
a treatment plant on the lands at Arnos Vale. In this scenario all sewage shall be pumped to
Arnos Vale. The recommended treatment process shall then be the Extended Aeration Process
which is low in capital cost, robust, easy to maintain and operate, odour free and produces a

sludge which is well oxidized and stable compared with sludge produced by other processes. It is
important to note that due to lack of available land space in Kingstown, Lamella Plate Separators
would be required, which are high in capital and operational cost, and have a high maintenance
requirement, which would be a problem in St. Vincent.
The proposal is also to simply produce cake sludge by mechanical dewatering and dispose to
landfills and use on land to improve soil fertility. In this proposal, a new outfall for marine
disposal will have to be constructed at Arnos Vale.

Future Direction
It is proposed to have a phased approach for implementation of the project. Under stage 1,
several items shall be completed.
i.
New connections of premises not yet connected to the existing system.
ii.
Inclusion and necessary changes to have sullage discharged into sewers
iii. Extension of Kingstown sewage catchment to include nearby surrounding areas of
Kingstown
iv. Refurbishment of sewage collection facility i.e. construction of screens, enclosing of
facility
v.
Construction of a new out-fall in Kingstown.
vi.
Construct sewers in South Coast area.
vii.
Construct pumping stations and mains to transmit sewage to Kingstown.
This phase is estimated to cost approximately EC$23,000,000.
Stage 2 shall basically consist of construction of the treatment plant at Arnos Vale, and
construction of a new outfall at Arnos Vale. This, however, shall not take place for another 10
years at least. This phase should cost an additional EC$17,000,000.

Conclusions
In developing the project further more investigation and thought needs to be put into the type of
treatment adopted, and ensure that the process adopted works under our local conditions. Work is
still yet to be done on costing and design of the outfall at Arnos Vale. Also, it must be considered
how phasing impacts on the design and construction, e.g. can pumping simply be reversed when
the treatment plant is at Arnos Vale. However, there is now a firm grasp of what is required to
address the wastewater treatment needs in SVG.

List of References
Howard Humphreys & Partners Ltd.
Study to review the treatment and disposal of Kingstown's Sewerage, St. Vincent, 1997.
Metcalf & Eddy
Wastewater Engineering � Treatment, Disposal & Reuse, 3rd Edition, McGraw Hill.
Persons Consulted
Brian DaSilva � Engineering Manager, CWSA, St. Vincent and the Grenadines.

Regional Workshop for the Wider Caribbean Region on Adopting,
Applying and Operating Environmentally Sound Technologies for
Domestic and Industrial Wastewater Treatment
Khansham Kanhai
Technical Adviser to the Minister of Public Utilities, Government of the Republic of Trinidad and Tobago

Introduction
In the modern world, the development of any country can be measured based on infrastructure,
facilities and prevailing sanitary conditions. The standard of living of a country can be judged by
the prevailing hygienic conditions, which in turn, are assessed on the level and quality of water
supply and collection, treatment and disposal of liquid and solid wastes.
In Trinidad and Tobago, under the Water & Sewerage Act, 1965, the Water and Sewerage
Authority (WASA) is responsible for both water supply and public sewerage systems. From
1965 to the present, the focus was mainly on expanding the potable water supply to meet the
increasing demands of both domestic and industrial consumers, as attested to by the fact that
approximately 95% of the country has access to a potable water supply, but less than 25%
of the country has access to centralized sewerage systems.

Initiatives In Water Sector Development
As opposed to the sewage sector, much progress has recently been made in the development of
potable water supply systems. The large Industrial base in Trinidad and Tobago has perennially
presented stressful demands on the existing water resources, and with the recent initiatives by
Government to further encourage the expansion of the country's Industrial base, especially at the
Point Lisas Industrial Estate, the water supply situation is expected to reach critical proportions
by the year 2000.
In fact, there is a present water supply deficit of approximately 18 mgd in Trinidad and Tobago,
and within the next 5 years or so, it is expected that this deficit will increase to approximately 39
mgd if no additional sources are developed. It is in this scenario that the Government, in
consideration of the limited funding available, has embarked on a number of priority projects to
concentrate on water supply rather than on the sewage sector. Some of these projects include the
provision of some 20 mgd of additional potable water into the transmission and distribution
system together with the installation of a desalination plant at the Point Lisas Industrial Estate
dedicated to the Industrial consumers who are presently being charged a higher tariff than other
consumers. All these initiative are targeted to be completed during the year 2000.
However, it has been recognized that the provision of water generates the production of sewage.
With this in mind, the Government has also been actively preparing for the next stage in the
development of the Water and Sewerage Sector to deal with issues relating to the maintenance
and expansion of the existing sewerage system, constructing and developing new sewage works,

adopting and rationalizing private sewage systems, and establishing the legal framework for
control and monitoring of all wastewater systems in the future. The Environmental Management
Authority (EMA) has been appointed by Government to establish and implement a Pollution
Control and Monitoring Programme to ensure compliance by all owners and operators of
wastewater treatment facilities.

History of Wastewater Sector
The first sewerage system in Trinidad was constructed in Port of Spain in 1861, and was
progressively upgraded to serve areas immediately west of the capital city, i.e. Mucurapo and
environs, until 1937. In 1965 however, the Government of Trinidad and Tobago undertook the
largest single sewerage project in the country's history when the Port of Spain system was
upgraded and extended to serve as far as Point Cumana in the west and San Juan in the east. This
project also incorporated the construction of centralized sewerage systems within the then
Boroughs of San Fernando and Arima.
In the last 30 years, the development of the sewerage sector has been virtually at a standstill.
Besides the provision of sewerage services to the city of Scarborough in Tobago, no major
development has taken place in the sewerage sector since 1965. This situation has generated
major concern by the present Government and a Task Force has been appointed to develop a
National Policy for the Wastewater Sector Development.

Existing Public Systems
Since the Authority was incorporated in 1965, growth within the public sewerage sector has been
realized primarily through the adoption of seven (7) small private systems. Currently the
Authority owns and operates 12 wastewater systems - comprising 12 treatment plants and
22 pumping stations. These systems serve a population of approximately 250,000.
The four urban centres at Port of Spain, San Fernando, Arima and Scarborough account
for the majority (95%) of the wastewater generated within the public systems, while the
remaining eight smaller systems account for a mere 5% of the total wastewater treated.
Over the years the collection systems, pumping stations and treatment plants have deteriorated to
such levels that major refurbishment works are required to restore satisfactory
performance and reliability to these systems. Current budget allocations do not support
improvement works in the sewage sector since the concentration of efforts has traditionally been
in the production of potable water to meet consumer demands.

Existing Private Systems
Considerable housing and industrial development has taken place over the last two decades and
is continuing to take place in many areas of the country irrespective of the fact that the expansion

of the existing network of centralized sewerage systems has not kept pace with this development.
Developers therefore have been required to construct, operate and maintain their own private
wastewater systems and this has resulted in the proliferation of numerous small private
wastewater systems all over the country. This is clearly evidenced by the fact that the estimated
150-odd private systems (including those operated by state agencies such as the National
Housing Authority) serve a mere 10% of the population of the country.
The operation and maintenance of these private systems has remained the responsibility of the
respective owners and the recently concluded Adoption Strategy Study, occasioned by the
Government and conducted by a joint GORTT/WASA/TTWS Team, is targeted to address the
rationalization, adoption, maintenance and expansion of these systems.
Until this Strategy is implemented, the private owner/operator remains responsible for the
operation and maintenance of the private wastewater system within the constraints of the Public
Health Ordinance, Water and Sewerage Act, Environmental Management Act, and other relevant
legislation.

Legal Aspects
It is noted that:
i. Under Section 62 of the Water and Sewerage Act, Chapter 54:40, WASA is
responsible for:
a. Maintaining and developing the existing sewerage system, and all
sewerage works vested onto it,
b. Constructing and developing such further sewerage works as it
considers necessary or expedient, and,
c. Administering the sewerage services, thereby establishing and
providing sewerage facilities in Trinidad and Tobago.
ii. Under Section 65 of the same Act, the Water and Sewerage Authority, by
Order may divide Trinidad and Tobago into sewerage areas for inter alia:
� Vesting in itself any sewerage works constructed in such
areas as well as the existing sewerage system
iii. By Legal Notice No. 97 of 1987, the entire country of Trinidad and Tobago
has been divided into five (5) distinct sewerage areas:
� The Port of Spain Sewerage Area
� The San Fernando Sewerage Area
� The Arima Sewerage Area
� The Trincity Sewerage Area

� The entire country of Trinidad and Tobago excluding the
Port of Spain, San Fernando, Arima and Trincity Sewerage
Areas

Trade Effluent Discharges
The discharge of high-strength waste into the public sewers is a matter of concern to the
Government and one which is to be addressed by the development of appropriate
regulatory procedures, wastewater tariffs for trade effluent, as well as monitoring and
control systems to manage this aspect of the Authority's operations.

Wastewater Tariff
Sewerage tariffs in Trinidad and Tobago are low both in absolute terms and relative to water
supply charges. The rates charged for sewerage services are a poor reflection of the cost of
providing those services.
In England and Wales, the tariff reflects the cost of provision of sewerage services and the
average sewerage tariff (US$1.78/m_) is more than the water supply tariff (US$1.54/m_). In
Trinidad and Tobago, the reverse holds, as the sewerage tariff is only 50% or _ of the
water supply tariff.
The necessary funds will have to be provided to finance the development of Sewerage Sector.
Such finance will have two (2) separate and distinct elements, namely:-
� Initial costs to provide infrastructure for new sewerage systems or expand/up-grade the
existing sewerage systems and treatment plants
� Continuing funding (revenue) for the operation and maintenance of the various sewerage
systems.
This requires the preparation of a new and comprehensive wastewater tariff which is directly
related to the true costs of sewerage and sewage disposal services.
A recent study by the Government, engaging the services of the international firm of London
Economics, has produced several recommendations for tariff increases and this is currently being
reviewed prior to implementation.

Current Projects/Studies
A number of initiatives are currently being pursued by the Authority in an attempt to improve
system performance, as briefly discussed below.
� Water Supply and Sewerage Rehabilitation Projects (WSSRP)
Works funded jointly by the World Bank (WB) and the European Investment Bank (EIB)
totaling $21.3m have been proposed under this program for the complete refurbishment of 9
treatment plants and 21 pumping stations operated by the Authority. Actual construction work on
this project is expected to start in early 1999, in accordance with current schedules.
� Greater Port of Spain Sewerage System Study (GPOSSSS)
A study funded by the Caribbean Development Bank valued at $7m to evaluate the Greater Port
of Spain Sewerage System has been completed in September 1998 and is also under review prior
to implementation. Due to the lack of funding and in consideration of the urgent need to improve
the quality of effluent discharge from the main sewer treatment plant serving the area,
Government is presently looking at the possibility of encouraging private sector participation for
the development of the sector in the Greater Port of Spain Area.
� Minor Projects/Studies
� A study funded by the Tobago House of Assembly and valued at $0.5m,
aimed at developing proposals for the integration of the Signal Hill
sewerage system into the existing Scarborough sewerage system, is
currently underway.
� Proposals to improve the existing wastewater systems within the South-
West region of Tobago have been submitted by the Trinidad and Tobago
Water Services (TTWS) on behalf WASA. Preservation of coastal
environment in Tobago as is relates to and affects recreation and the
marine ecology with special reference to the Buccoo Reef reinforces
the urgent need for the implementation of this project.
� Emergency works have been planned and capital funding has been
requested against the following system components at Beetham:
1. Force Main: to repair badly deteriorated 48" diameter
pipes,
2. Pumping Station: to upgrade mechanical, electrical and
instrumentation equipment.
�

Adoption of Private Systems
As mentioned before, a strategy for the adoption of privately-owned wastewater systems has
been prepared by the Trinidad and Tobago Water Services on behalf of the Government of
Trinidad and Tobago and the Water and Sewerage Authority, and is currently engaging the
attention of the Government.

Key Issues

1. Need for a national wastewater policy.

2. Institutional strengthening of the Sewerage Sector in WASA.

3. Development of a Wastewater Master Plan for Trinidad and Tobago.

4. Policy on private wastewater systems in Trinidad and Tobago
� for existing systems
� for new systems

5. Development of regulatory and monitoring mechanisms to control the discharge
of trade effluents in to the public sewers.

6. Implementation of appropriate wastewater/sewerage tariff for Public (WASA) &
Private Wastewater Systems.

7. Provision of centralized sewerage systems at all urban centres and industrial
estates.

8. Strategy to integrate smaller wastewater systems.
9.
Funding.

Major Policy Framework to Address Key Issues
The following actions have recently been instituted by Government to address the key issues
discussed in the preceding section:
1. Appointment of a task force in May 1998 to develop a national policy for the wastewater
(sewerage) sector development.
2. Institutional strengthening of the Sewerage Sector, funding for which is being pursued
with the World Bank and the EIB.
3. Wastewater master plan for Trinidad and Tobago based on the recommendation of the
Government appointed Task Force.

4. Review of wastewater/sewerage tariffs to appropriate levels with respect to:
o Domestic wastewater discharges (tariffs should be at least equal to that of water),
and
o Trade effluent discharges.
5. Development of trade effluent discharge regulatory procedures and monitoring system to
control trade effluent discharged into public sewerage systems being done by the EMA.
The EMA to establish and implement a Pollution Control and Monitoring Programme to
ensure the compliance by the private owner/developer of the wastewater system until
such time that they are adopted by the Water and Sewerage Authority based on their
technical and economical viability.
6. Establish a joint focus team of stake-holders to develop and agree on the action plan
based on the TTWS final report on the adoption of private sewage treatment works
(November 1997) on adoption of private wastewater systems.
7. Interim provision for private owner of wastewater systems to charge sewerage rates from
the residents/users of these facilities once the owner efficiently operate and maintain the
wastewater system and meet the effluent discharge conditions set by the EMA. This
measure must be of a temporary nature and after a defined period, the Water and
Sewerage Authority must accept the eventual responsibility for operating and maintaining
these systems. The defined period will be determined by:
� WASA's adoption strategy and action plan, and
� EMA's advice based on the compliance of the discharge permit condition over
a period.

Future Vision
The future vision in the wastewater sector in Trinidad and Tobago is to have centralized
sewerage systems at all urban centres, industrial estates, suburban developments and village
communities (representing approximately 90% of the population of 1.3M) efficiently operated,
managed and maintained to satisfy environmentally-friendly effluent discharge standards,
financially supported by sustainable tariff levels.
Deterrents to this vision have been principally identified as the shortage of funding and the
urgent need to fast-track the legislative monitoring and control mechanisms.
However, the number of initiatives presently being undertaken by Government are geared
towards surmounting these hurdles and achieving this vision, and have most certainly involved
the adoption and application of environmentally-sound technologies for wastewater treatment.

Acknowledgements
1. Policy Paper for Wastewater/Sewerage Sector Development (May 1998) - M. Kerof
2. Status Report on Sewerage Sector in Trinidad and Tobago (June 1989) - D. Sharma, M.
Kerof, A.S. Tota.
3. WASA Tariff Study Report (March 1998) - London Economics/Castalia
4. Adoption of Private Sewerage Treatment Works (1997) - GORTT/WASA/TTWS
5. Greater Port of Spain Sewerage System Study Report (September 1998) - Reid
Crowther/Alpha Engineering.

Treatment of Wastewater Discharges to the Greater Caribbean Area
Louis Salguero
UNITED STATES OF AMERICA

Improving the water quality in the greater Caribbean area is a vision which can be made a reality
through cooperation. The communities of the greater Caribbean area are connected physically to
each other by water. This fluid of water provides for the economic, ecological, and spiritual
benefit of all men. The Gulf of Mexico which embraces the Caribbean Sea is bordered by five
North American states (Florida, Alabama, Mississippi, Louisiana, and Texas). The habitats and
ecosystems along this American coastline are diverse and critical for helping to maintain the rich
abundance of marine wildlife in the Gulf. Fresh water from the United States flows into the Gulf
bringing nutrients and sediment to help feed these activities. The Mississippi River alone brings
to Gulf 1.06 trillion cubic metres of fresh water. The Loop circulates the waters of the Gulf
starting from the Yucatan Strait and existing through the Straits of Florida. To protect this fragile
environment in 1988 the Federal Government, the Gulf States, business, industries, non-profit
organizations, educational institutions, and other interested stakeholders joined forces to form the
Gulf of Mexico Program. This program raised environmental protection to a new level of multi-
involvement and cooperation in the United States. As members of the Greater Caribbean
community the United States also wants to participate in making the vision of improving water
quality in the Caribbean Sea a reality.
The first step in protecting these waters has been made possible as a result of technological
breakthroughs in communication. And that step is awareness. Awareness that the environment is
a living global entity that can only be protected through the cooperation of all people and all
governments. Vast amounts of environmental information can now be accessed on the Internet to
drive this awareness.
I would like to talk about the wastewater problems of the Central American region and
appropriate wastewater technologies needed to solve them. Through an interagency agreement
US-AID and the US-EPA are providing technical assistance tot he Central American countries in
addressing their environmental problems. I have traveled to several Central American countries
to view the wastewater problems of the region. The wastewater problems faced by these
countries are great but not insurmountable. The developing countries most find appropriate
solutions that are low in cost and that use technologies that are simple to operate. Low in cost not
only in initial installation but in operation. Activated sludge wastewater treatment plants are high
in energy consumption and thus invite high energy cost. There may be situations where an
activated sludge system is necessary but other appropriate and alternative wastewater treatment
systems should be evaluated.
Presently, wastewater from most industries and municipalities in the region are not receiving any
wastewater treatment. Municipal discharges to receiving streams are high in BOD, TSS, fecal
coliform, and nutrients. These receiving streams eventually flow into either the Pacific Ocean or
the Caribbean Sea. In addition, there are direct discharges to the Caribbean Sea from port towns.
One of these towns that I am working with is Puerto Barrios in Guatemala.

Slide Presentation Starts:
The people of Puerto Barrios have asked for help in solving their wastewater problem. The
problems are septic discharges to rivers that flow through the town into the Gulf of Honduras.
There is no sewer collection system in the town and open ditches are used to collect wastewater.
The ditches are flushed only during storm events. To complicate the situation the ground water
table in some cases is only centimetres from ground level. Traditional collection systems would
be very expensive to install.
A pilot project is being proposed where a small diameter collection system will be used to
transport the filtrate from septic tanks in a one block area to a main collection tank for pumping.
The pumped wastewater will be treated in an recirculating sand filter. Treated effluent from the
sand filter will then be discharged to the Rio Escondido.

Slides of Appropriate Technologies:
At this point, I would like to show slides of some appropriate technologies for developing
countries:
� Rich Lagoon System
� Sand Filters
� Alternative Collection Systems
� Sand Filters used in the State of Tennessee
� Water Tight Septic Tanks
� Slow-rate Trickling Filters

Adopting, Applying and Operating Environmentally Sound Technologies
for Domestic and Industrial Wastewater Regional workshop for the
Wider Caribbean Region
Fanny Rodr�guez
VENEZUELA

Introduction
The Ministry of Environment and Natural Renewable Resources is uncharged for deciding rules
about defense, conservation and improvement of the area that includes Lake Valencia Basin, of
executing researches, Studies and projects and building sanitary infrastructure needed for giving
a solution to the environmental problem in this basin, one the most populous area in the country.
The increase of population till 2.5 millions people ( 13% of all the country ) joined by the fast
expansion of industry (30% of all the country) and agriculture has provocated a very high
degradation in this basin and for this reason the Venezuelan Government, conscious of this
problem has been working during the last years, through the Ministry of Environment and
Natural Renewable Resources, in various studies about the Lake Valencia with the purpose of
identifying the problems in the Lake Basin, for obtaining necessary knowledge that will bring
concrete information for action policy formulas to correct or control pollution situations that
appears in this important water reserve and his basin, preventing actually any kind of use.
Results of this work is the basic purpose of obtaining the Lake Valencia Sanitation as well as his
affluents, with the actual construction of the following waste water treatment systems:
La Mariposa and Los Guayos on the Valencia - Guacara Zone.
Taiguaiguay on the Maracay Zone.
Lake Valencia is one the greatest water bodies in the northern part of South America, it covers an
approximate area of 350 square kilometers and receives water from several rivers.
The most pollution levels are present in areas under direct influence of rivers that drain the
principle urban and industrial zones.
Sources and type of pollution:
The wastewater effluent can be categorized according to their sources:
-Domestic Effluents
-Industrial Effluents
-Livestock activities
-Agriculture activities

Industries in the Catchment Area
Primary Industry: Sugar cane, fruits, vegetables, cattle rising.
Secondary Industry: Metallurgy, oil and deviates, paper and cellulose, chemical and
agrochemical, nourishing, alcoholic and non alcoholic beverages.
Tertiary industry: Financial activities, government's activities, and commercial activities.
For regulation this activities was established Decree N� 883. The present Decree establish the
norms for the control of the quality of the bodies of water and poured liquids, published in
official Newspaper N� 5021, dated 1985.

Project of the System for the Treatment of Residual Waters in the Basin of the
Lake Valencia
Having concerned with such environmental problem of the Lake ,the Government has been
undertaking several series of investment, studies and projects related with water quality
improvement, flood control and water transfer- supply under the Integral Program for
Environmental Improvement of the Basin of Valencia Lake. Above all, the lake basin sewage
system with there wastewater treatment plants has been developing, supported financially by
IDB (Inter American Development Bank). This sewage system is expected to be operated within
few years and contributed to improve water quality of the lake, eliminating more than 90% of
organic pollutants flowing into the lake.

Conceptualization of the Project
The execution of the project will eliminate 90% of the contamination of the waters of the lake
caused by:
� Intensive industrialization in the basin.
� The rivers flow toward a closed valley.
� Natural drainage transport waste, which end up in the lake.
� A floweret of 6,7 m3 /s from municipal waters not treated are discharged directly into the
lake.
� The lake behave like a biological reactor ,where biodegradable residues are consumed
and the non biodegradable are transformed in solutions or silt.
The program contemplates specific projects in the following stages:
� Project. Supply of drinkable water for the population in the basin.
� Project Treatment System for served water from domestic and industrial use.
� Project Control the level of lake and contraction of pluvial drainage and special
financement studies.

Complementary Activities:
� Program to control industrial effluents, Ordinances 883 and environmental Penal Law.
� Fare Study and Methods of Controlling Industries Effluents.
� Training Program for professional personnel for the maintenance and operation of the
treatment plants.
� Study the project for 3rd, stage which will allow to determined the factibility and
convenience of doing this work and control it, like :
Factibility study and the design of treatment system of residual water for la Victoria and Guigue
cities.
a. Factibility study and the design of works for an intensive development of la Cienaga del
Paito area.
b. A non punctual contamination study due to agricultural activities.
c. Contamination study and over exploitation of under ground waters of basin.
Additional gain:
� The recollection work and treatment proposal, will reduce the volumes of water dump
into the lake, reusing about 3.8m3/s for irrigation in the East side and 2.4 m3/s for
irrigation in the West side.
� The project will contribute to diminish the average ascend of the lake, from 43 cm to 11
cm per years and the progressive recuperation of the aquifers that are overuse at the
present.
� Concerning irrigation, it is estimated that in the Taiguaiguay area, 5400 hectares will be
irrigated with treated water from the city of Maracay.
� Depending on the degree of recuperation of the lake Valencia, we hope to be able to use
the water as a source for human consumption from the Central Region and Metropolitan
Area of Caracas.
Socio-Economical Justification of the Project:
� The project provides primary collectors and treatment plant to the present local sewage
system in urban areas of Maracay and Valencia cities.
� The project allows the use of treaties effluents for irrigation.
� It will contributed to diminish the rate of ascend of the level of the lake.
� The recommended solution and presented in this proposition is MINIMUM
ECONOMICAL COST, TECHNICALLY POSSIBLE.
Additional Benefits:
� Reduction of use of under ground water for irrigation in the basin.
� Reduction of possibilities of infrastructure loss due to subsidence of the land, and over
exploitation of aquifers.
� The lake could be used for urban supply, mix with other sourcer.

� The possibility of introduce commercial fish farming.
� The use of treated serve water, which are rich in phosphorus and nitrogen, will save in the
in use of fertilizers .
Payment Capacity:
Only 1% of the families living in the area will compromise 3% of their earnings, for the payment
of potable water and sewage system combined.

Maracay System
Near Maracay, there is reservoir feeding an extensive irrigation system which is underused due
to lack of water. To remedy the water shortage, the city is intercepting sewer will terminate in a
central pumping station from which screened and degraded sewage will be pumped through a
1.80 rising main 17 Km to lagoon system with a stage 1 mean design flow of 5 m3/s built on
public land on the Northern edge of the reservoir.
Sewage from the towns of Cagua and Turmero will join the inlet channel of the lagoon system.
The lagoon system will consist of four anaerobic reactors of one day retention time followed by a
facultative lagoon of 5 days detention time before discharge into the irrigation reservoir. The
reservoir will store the effluent during the rainy season for release for irrigation during the dry
season (December-May). In this way, effluent discharge to the lake from the Maracay area will
be reduce practically to zero until the peripheral aquifer recuperate. Recycle from the facultative
lagoon will be used to raise the pH and reduce odors from the anaerobic reactors.

Valencia System
The sewage from the Eastern, predominantly industrial, areas of Valencia will be carried to the
Los Guayos lagoon system, described previously of 2 m3/s mean design flow and used for
irrigation during the dry season. During the wet season the effluent will discharge to the lake.
The sewage from the central and Western, primarily domestic and commercial areas of Valencia
will be conveyed to the Mariposa treatment plant used for irrigation in the dry season. In the wet
season, the effluent will be discharged to the Pao river system as planned indirect reuse. The Pao
dam is eutrophic due to diffuse nutrient sources from agriculture and uncontrolled sewage
recycle. This make its water odorous and difficult to treat for potable use because of large
numbers of Naviculas which reduce filter runs to as little as 6 hours at times.
The Mariposa plant will therefore be more advanced than the other treatment system and will
employ biological nutrient removal, tertiary filtration and polishing in a natural wetland.
The plant will consist of four treatment modules each for 200.000 population equivalents and
600 l/s mean design flow each, based on modification of the activated sludge process, followed

by rapid gravity filtration to remove residual solids bound phosphorus and also to act as barrier
to helminthes and protozoa cysts. Waste sludge will be thickened by gravity and dried in
lagoons, stored for one year and them, subject to heavy metal content, be used in agriculture.
Artificial disaffection such as chlorination has not been envisaged in order to permit maximum
natural biodegradation and removal of pathogens in the 20 Km marsh and natural river course
between the plant out fall and the Pao dam.
A number of details of plant have been simplified in line with prevailing human resource
limitations. The screens will be manually raked; the aerator will be high speed direct drive bridge
mounted and sophisticated control system will be kept to a minimum. The filters will be of the
declining rate, declining level self backwashing type, reducing the number of valves to only two
per filter.

Environmental Education
Concerted efforts are carried out by both Government and the citizen in a necessity for proper
Lake Valencia Basin development. It is therefore very important educate the citizen on the Lake
Environmental Problems.
Lake Valencia has a great natural beauty, but it is not well know. Implementation of
environmental education programs in the formal education is necessary, because the Lake
Valencia is still considered by most of community like an enormous open sewer.
Is of big importance the diffusion in the Regional television, campaigns of environmental
preservation altogether with education, participation and relation with usurious management of
Lake Valencia Basin.

Conclusion and Recommendations
The big problem in the Central Region of country is the Lake Valencia Eutrophication, by
pollution of water of its tributaries rivers.
The Project of System for the Treatment of Residual Water in the Basin of Lake Valencia is the
key for to improve water quality of the lake but it is only the beginning, in consequence,
according to the current state of the Lake, it is necessary to make a more exhaustive study for
what is recommended:
� To continue the studies of physical � chemical parameters in integral and systematic form
of the water of the lake.
� To carry out a fish study, as for changes of diversity and content of accumulative
substances

� To determine the concentration and distribution of toxic organic substances and heavy
metals in the water and sediments.
� To carry out measurements of the speed and direction of the movement (current) of
water, to understand the diffusion process that affects the distribution of polluting
substances in the lake.
� To continue with the study of identification of phitoplancton and zooplancton .
� To continue with the study of bentic organism in sediment of the lake, due to being
indicator of quality of the water.
� To make a study of punctual and non punctual sources of the basin that discharge into the
lake and they have not been studied.
� To determine the concentration of atmospheric pollutant in the rain water and their
influence in the lake.
We must to have in consideration that when the project is completed, Lake Valencia water will
only be used for irrigation subject to improvement over the years. Constant monitoring of the
water quality, sediments and biota will be carried out to assess when it will become suitable for
domestic use. This can occur in 10,20 or 30 years time.

PART 3

GROUP DISCUSSION

Table of Issues, Existing Technologies and Future Possible Options
The final session was a Group Discussion to develop action plans for the future. Four groups
separately listed the issues, existing technologies and future possible options in their countries.
Each group was given three (3) stickers for three (3) former categories. Each group then rated
each entry for its priority or prevalence by placing three (3) stickers on their chosen entries. The
numbers after each line item represents the summation for the group (i.e. the higher the number
the higher the priority or prevalence). The following tables document the results of these group
discussions.

GROUP 1
PARTICIPANTS:
Anguilla:
Mr. Stephenson Rogers
St Kitts & Nevis:
Mr. Errol Rawlins
Antigua & Barbuda:
Mr. David Mattery
St Lucia:
Ms Francine Clouden
Barbados:
Mr. Anthony S Headley
St Lucia:
Mr. Errol Frederick
France:
Mr. Eric Muller
Trinidad & Tobago: Mr. Kansham Kanhai
Facilitator: Assoc. Prof. Goen Ho, Australia
ISSUES
EXISTING TECHNOLOGIES
FUTURE
Marine pollution (7)
COLLECTION
COLLECTION
Lack of legislation and standards (4)
Pit latrine (6)
More central sewerage (with
treatment) (6)
Training of personnel (4)
Night soil (1)
Training and public education (4)
Lack of maintenance (3)
Rationalisation of existing system
Lack of enforcement/ management (3)
(2)
Small bore sewerage (1)

Lack of funding (2)
TREATMENT
TREATMENT
Lack of education (public) (2)
Septic tank (10)
Improved on-site system (9)
High level of nitrates (aquifer) (1)
Packaged treatment plant (6)
Management of night soil (1)
Activated sludge (2)
Lack of institutional frameworks
Grease trap (1)
Limited land space
Ponds (1)
High water table
Filter bed
Appropriate tarn-f structure
DISPOSAL
DISPOSAL
Lack of monitoring/data
Aquatic
Reuse and recycle (5)
Improper effluent disposal (st)
No treatment
Sewage management outside sewered
Marine outfall (no treatment)
areas
Lack of regional policy
Laboratory accreditation
Water scarcity/regular supply

GROUP 2

PARTICIPANTS:
Aruba
Mr. Elton Lioe-A-Tjam
Jamaica
Mr. Donald McDowell
Bahamas
Ms Christal Francis
Jamaica
Mr. Errol Motley
British Virgin Island
Mr. Mukesh Ganesh
Jamaica
Mr. David Steen
Haiti
Pierre Carlo Lafond
Netherlands Antilles
Mr. Patricio D Oleana
Jamaica
Mr. Bruce Excell
Netherlands Antilles
Mr. Arthur Rodriguez
Jamaica
Ms Stephanie Fletcher
Trinidad and Tobago
Mr. Kansham Kanhai

Facilitator: Dr Kuruvilla Mathew, Australia
ISSUES
EXISTING
FUTURE
TECHNOLOGIES
Maintenance (5)
COLLECTION
COLLECTION
Enforcement of legislation (5)
Pit Latrines (2)
Sewer system (4)
Finance (5)
Community pit latrines (1)
Small diameter systems with effluent
reclamation (2)
Upgrade and improvement (5)
Aqua � privy
Pit Latrines (sanitary VIDP) (1)
Planning for future (4)
TREATMENT
TREATMENT
Pollution of coastal waters (3)
Septic tanks (8)
Activated sludge (8)
Lack of resources (1)
Lagoons (5)
Septic tanks (5)
Integration of management policies
(1)
Oxidation ditch (4)
Wet lands (4)
Land availability (1)
Activated sludge system (4)
UV Disinfection (3)
Training of operators
Trickling filter (2)
Lagoons (3)
High water consumption
Package plants (2)
Oxidation Ditches
(conservation)
Sludge digestion
Sand filters
Botanic (aquatic)
DISPOSAL
DISPOSAL
Sea outfall (1)
Small diameter systems with effluent
reclamation (2)
Bag disposal method (1)
Ground infiltration

GOALS ACTION
1 Conventional pit latrines should be
Set goal for improvement of systems/areas to be covered
discouraged
in timeframe.
2
Rehabilitation
Community Awareness � incorporate social and cultural
3
activities.
Awareness � Education of policy marers as
4 well as decision marers
Associate with NOWRA

Sectoral approach � master plan
Training and education:
5 Achievable goals � time limits
- user friendly; communication to owners; should be able
to adopt as own system.
6 Monitoring
- maESTro � to be encouraged

Enforcements of international treaties:
Regional coordination program
- facilities need to be in place for ships to
7 discharge in harbour
Vessels should have holding tanks

GROUP 3
PARTICIPANTS:
Cabo Verde
Mr. Antunio Barbosa Jamaica
Mr. Matthew Krachon
Canada
Mr. Jean-Pierre Dube Jamaica
Mr. Cliff Reynolds
Canada
Mr. John A McKee Jamaica
Mr. Roger Surtees
Canada
Ms Christiane Roy USA
Mr. Ted Loudon
Jamaica
Mr. Peter Collins USA
Mr. David Pask
Jamaica
Ms Ining Hsu

Facilitator: Ms Christiane Roy, Canada
ISSUES
EXISTING TECHNOLOGIES
FUTURE
Political Will (10)
COLLECTION
COLLECTION
Education (5)
None (6)
Rehabilitation (3)
Money � Capital (4)
Septic tank effluent (3)
Easily upgradable (3)
- O & M (4)
Municipal gravity sewer
STEP and STEG (3)
Cultural values (4)
Septage haulind
Assistance in connection (2)
Legal framework (3)
Surface/Gulleys
Water segregation (1)
Management (2)
Gravity
On-site
Public health (2)
No dig
Training (1)
Cluster
Motivation (1)
Extension of existing system
Enforcement (1)
Standard gravity
Standards
TREATMENT
TREATMENT
Monitoring
Lagoons (4)
Low Tech (RSF, ISF, reed beds,
Lagoons) (8)
Technology perceptions
None/Honey bags (3)
Upgrading (1)
Public awareness
St & Absorption pits (1)
VIDP and others (1)
Natural resources
VIDP
Tertiary (N.P. Disinfection) (1)
Subdivision practices
VIP
Standardization
Social issues
Package plants
Community
Affordability
Activated sludge
Maintenance
Reed beds
Rehabilitation
Sand filters
On-site
Recir. Filter

DISPOSAL
DISPOSAL
Sea outfall (8)
Reuse water (7)
Reuse (3)
Irrigation (1)
Soak away pits (2)
Offshore disposal (1)
Deep well injection
Reuse sludge
Inland rivers
Groundwater recharge
Surface disposal
Soil conditioning

EDUCATION PHASE
PLANNING PHASE
GOALS
Involve private sector early
Must continually assess
effectiveness of education phase
Academics involved in R.B.A. and
continuing education
Technically part of planning phase
must follow education phase and
Money:
utilize its results
-perhaps funding from
private/commercial (make it a
Plan for O & M -- training
business)
-- funding
- creative financing
Accountability
Emphasize the cultural values/issues
Creative financing
Simultaneous action at political and
community level
Project management beginning to
end
Focus on practical action
(deliverables)
Not a handout � system controlled
by people

ACTION
Risk based assessment
Some assessment of R.B.A
initial solutions:
Initial survey (person to person)
- current situation (1)
- eliminate infeasible solutions
- public opinion (3)
- leadership development
- community leaders
Develop education strategy (based
on survey
(and therefore continuous feedback)
Technical workshops:
Arise from Technical Workshops:
- Government
- Professionals
- goals
- Consultants
- priorities
- Social works
- means
- Industry
- action
- NHO's
Critical Path Diagram
Educate Public � Political Action

GROUP 4
PARTICIPANTS:
Belize
Mr. Jose Medoza
Mexico
Dr Felipe Cortes
Colombia
Dr Serigo Cruz Fierro
USA
Mr. Louis Salguero
Cuba
Ms Carmen C Berro
Venezuela
Ms Fanny Rodriquez
Guatemala
Mr. Adan Collazos

Facilitator: Dr Martin Anda, Australia
ISSUES
EXISTING TECHNOLOGIES
FUTURE
Operation of management (4)
COLLECTION
COLLECTION
Lack of financial resources (8)
Latrines (2)
Simplified collection systems (1)
Capacity building (3)
Dry toilets
Collection systems w/minimal leakage (1)
Political will (3)
Small diameter pipes

Lack of plan (development) (2)
TREATMENT
TREATMENT
Inappropriate technology (1)
Stabilization pond (10)
Environmentally friendly systems of
reasonable cost to all sectors (4)
Multisectoralism
Trickling filters (4)
Appropriate legislation � monitoring and
Training
Septic tanks (3)
enforcement (4)
Sensitive ecosystem
Imhoff tank (1)
Technology to remove industrial
pollutants (pre-treatments) (3)
Tertiary treatment (1)
Research and development of possible
Wetlands
treatment options (2)
UASB � Unit Anaerobic Sludge
Rehabilitation of existing systems (1)
Blanket
Aerobic/Anaerobic ponds
DISPOSAL
DISPOSAL
Ocean outfall
Recycle and reuse of wastes (5)

GOALS
ACTIONS
ISSUES

Lack of Financial Resources
Obtain Financial Resources
Debt Relief for Environment Protection.
Charge consumer for wastewater:

- Training
Operation and Management
Institute an Action Plan for a
- Networking of other Institutions
proper implementable Operation

and Management System
Training
Capacity Building
Institutional Strengthening
Meetings/Conferences for Politicians
Political Will
Public Awareness
EXISTING SYSTEMS

Stabilization of Ponds
Improve on Existing Systems
- Rehabilitation and Monitoring
Trickling Systems
- Pilot Projects
Septic Tanks

FUTURE
Increase the amount and quality
Education of Public and Cost
of available H2O supply
Watershed Protection
Develop appropriate laws and
regulations to protect water
Workshop/Seminars with relevant
bodies
organizations, etc
Network with other organizations
of acquisition of appropriate
technology

APPENDIX 1

PROGRAM

PROGRAM

Monday 16 November
8:30 a.m.

Registration
9:00 a.m.

Welcome

UNEP-CAR/RCU

Introduction

Mr. Vicente Santiago Fandino, IETC and Tim Kasten, CAR/RCU

Introduction of Participants and Presenters
10:30 a.m.

Coffee Break
11:00 a.m.
Session 1: Technology Choice and Sustainable Development

Mr. Martin Anda, Murdoch University
12:00 a.m.
Session 2: Development of a Protocol to Control Land-based Sources of Marine
Pollution

Mr. Tim Kasten, CAR/RCU
12:30 p.m.

Lunch
1:30 p.m.
Session 3: Principles of Wastewater Treatment

Associate Professor Goen Ho, Murdoch University
2:30 p.m.

Coffee Break
3:00 p.m.
Session 4: Field Trip to Montego Bay Wastewater Collection and Treatment System
5:00 p.m.

Return to Hotel and Adjourn
7:00 p.m.

Cocktail Reception at Hotel

Tuesday 17 November
9:00 a.m.
Session 5.1: Country Presentations from Delegates

Moderator: Murdoch University

Status of Wastewater Treatment Needs and Existing Technologies for
Large Communities: Technology Barriers and Recommendations

Summary of Existing Technologies and Future Options

Dr Arreguin Cortes, Mexico

Mr. Louis Salguero, USA

Mr. Carlo Lafond, Haiti
10:30 a.m.

Coffee Break
11:00 a.m.
Session 5.2: Country Presentations from Delegates

Moderator: Murdoch University

Status of Wastewater Treatment Needs and Existing Technologies for
Large Communities: Technology Barriers and Recommendations

Summary of Existing Technologies and Future Options

Mrs. Ianthe Smith, Jamaica

Mr. Kancham Kanhai, Trinidad & Tobago

Mr. Brian George, St Vincent & The Grenadines
12:30 p.m.

Lunch
1:30 p.m.
Session 6: Impacts of Organic Waste on the Marine Environment

Ms Christine Gault, National Estuarine Research Reserve, Waquoit Bay,
Massachusetts, USA
3:00 p.m.

Coffee Break

3:30 p.m.
Session 7: Wastewater Collection and Treatment Systems for Large Communities in
the Wider Caribbean

Mr. Mark Lansdell, Mark Lansdell & Associates, Caracas

Mr. Adan Pocasangre Collazos, CONAMA, Guatemala
5:00 p.m.

Adjourn

Wednesday 18 November
9:00 a.m.
Session 8: Country Presentations from Delegates

Moderator: Murdoch University

Status of Wastewater Treatment Needs and Existing Technologies for Medium and
Small Communities: Technology Barriers and Recommendations

Summary of Existing Technologies and Future Options

Mrs. Carmen Terry Berro, Cuba

Ms Christal Francis, Bahamas

Mr. Arthur Rodriguez & Mr. Patricio Oleana, Netherlands Antilles
10:30 a.m.

Coffee Break
11:00 a.m.
Session 9: Small Community Wastewater Treatment Systems

Ms Christiane Roy, Options Environment Inc., Montreal, Canada

Ms Francine Clouden, Caribbean Inst. of Environmental Health, St Lucia
12:30 p.m.

Lunch
1:30 p.m.
Session 10: Decision-making Software and Information Systems

"maESTro"

Mr. Vicente Santiago Fandino, IETC

"WAWTARR"

Mr. Chris McGahey, Vermont, USA
3:00 p.m.

Coffee Break
3.30 p.m.
Session 11: Field Trip � On-site Wastewater Treatment System
5:00 p.m.

Return to Hotel and Adjourn

Thursday 19 November
9:00 a.m.
Session 12: Treatment of Organic Waste from Industrial Facilities

Ms Julia Brown, Integrated Waste Water, Kingston, Jamaica

Mr. John A McKee, OMM Trow Consulting Engineers, Ontario, Canada
10:30 a.m.

Coffee Break
11:00 a.m.
Session 13: Country Presentations from Delegates

Moderator: Murdoch University

Status of Wastewater Treatment Needs and Existing Technologies for On-
site and Household Systems: Technology Barriers and Recommendations

Summary of Existing Technologies and Future Options

Mr. Errol Frederick, St Lucia

Mr. Mukesh Ganesh, British Virgin Islands

Mr. Anthony Headley, Barbados
12:30 p.m.

Lunch
1:30 p.m.
Session 14: On-site Systems

Mr. David Pask, Small Flows Clearinghouse, USA

Mr. Antunio de Cassia Sousa Babosa, Director of Ports and Marinas, Cape Verde
3:00 p.m.

Coffee Break
3:30 p.m.
Session 15: Household Systems for Wastewater Treatment

Dr Kuruvilla Mathew, Murdoch University

Professor Ted Loudon, Michigan State University, USA

Mr. Stephen Hodges, Construction Resource and Development Centre, Jamaica
5:00 p.m.

Adjourn

Friday 20 November
9:00 a.m.
Session 16: Group Discussion on Environmentally Sound Technologies

Moderators: Murdoch University and CAR/RCU
10:30 a.m.

Coffee Break
11:00 a.m.
Session 17: Evaluation, Feedback, and Future Direction

Moderators: ITEC, CAR/RCU and Murdoch University
12:30 p.m.

Group Lunch

Presentation of Certificates

Closing Remarks: IETC and CAR/RCU
2:00 p.m.

End of Workshop

APPENDIX 2

LIST OF RESOURCE TEAM

1

AUSTRALIA
CANADA

Mr. Martin Anda
Mr. John A McKee
Murdoch University
Oliver, Mangione McCalla
Environmental Science
154 Colonmade Road South
Murdoch WA 6150
Nepean, Ontario
Australia
Canada K2E7J5

Tel: (61-8) 9360-6123
Tel: (613) 225-9940 ext. 241
Fax: (61-8) 9310-4997
Fax: (613) 225-7337
Email: anda@essun1.murdoch.edu.au
Email: omm@trow.com

Mr. Goen Ho
Ms Christiane Roy
Murdoch University
Option Environment Inc
Murdoch WA 6150
2360 Avenue de La Salle
Australia
Bureau 202

Montreal, Quebec H1V 2L1
Tel: (61-8) 9360-2167
Canada
Fax: (61-8) 9310-4997

E-mail: ho@essun1.murdoch.edu.au
Tel: (514) 257-6380

Fax: (514) 257-6382
Dr Kuruvilla Mathew
Email: croy@opt-env.qc.ca
Environmental Science

Murdoch University

Murdoch WA 6150
GUATEMALA
Australia

Adan Ernesto Pocasangre Collazos
Tel: (61-8) 9360-2896
Executive Director of the Liquid and Solid Wastes
Fax: (61-8) 9310 4997
Council
Email: mathew@essun1.murdoch.edu.au
Conama

7a Ave. 7-13 Zona 13

Guatemala, Guatemala
CABO VERDE

Tel: (502) 440-7916/17
Antunio de Cassia Sousa Barbosa
Fax: (502) 440-7938
Director
Home Tel/Fax: (502) 474-3601
Directorate General of Marine Affairs

PO Box 7

S. Vicente
JAMAICA
Cabo Verde

Ms Julia Brown
Tel: (238) 324-342
Integrated Wastewater
Fax: (238) 324-343
Management Project
Email: dgmp@milton.cvtelecom.cv
Scientific Research Council

Hope Gardens

PO Box 350

Kingston 6, Jamaica

Tel: (876) 927-1771 to 4 ext. 3102

Fax: (876) 977-2194

Email: icomppm@cwjamaica.com

2

Mr. Stephen Hodges
UNITED STATES OF AMERICA
Construction Resource and Development Centre

11 Lady Musgrave Avenue
Ms Christine Gault
Kingston 10
Waquoit Bay National Estuarine
JAMAICA
Research Reserve

PO Box 3092
Tel: (876) 978-4061
Waquoit, MA 02536
Fax: (876) 978-4062

Email: crdc@jol.com.jm
Tel: (508) 457-0495 ext. 101

Fax: (617) 727-5537
Mr. Tim Kasten
Email: cgault@capecod.net
Programme Officer

UNEP-CAR/RCU
Mr. Ted Loudon
14-20 Port Royal Street
Agricultural Engineering Department
Kingston
Farrall Hall
Jamaica
Michigan State University

Farrall Hall
Tel: (876) 922-9267-9
E. Lansing, MI 48824
Fax: (876) 922-9292
USA
Email: tjk.uneprcuja@cwjamaica.com

Tel: (517) 353-3741

Fax: (517) 353-8982
JAPAN
Email: loudon@egr.msu.edu

Vicente Santiago Fandino
Mr. Chris McGahey
Programme Officer
Associates in Rural development Burlington,
Shiga Office
Vermont
1091 Oroshimo-cho, Kusatsu City
USA
Shiga 525-0001

Japan
Fax: 802-658-3890

Fax: 802-658-4247
Tel: (81-77) 568-4585
Email: cmgahey@ardinc.com
Fax: (81-77) 568-4587

Email: vstiago@unep.or.jp
AND

ST LUCIA
USAID CWIP

5 Oxford Park Avenue
Ms Francine Clouden
Kingston
Caribbean Environmental Health Institute (CEHI)
Jamaica
PO Box 1111

The Morne
Tel: (876) 754-3910/2
Castries

St Lucia
Mr. David Pask

National Small Flows Clearing House
Tel: (758) 452-2501
PO Box 6064
Fax: (758) 453-2721
West Virginia State University
Email: fclouden.cehi@candw.lc
Morgantown, WV 26506-6064

USA

Tel: (304) 293 4191 ext. 5516

Fax: (304) 293 3161

Email: dpask@wvu.edu

3

FIELD TRIP/TOUR GUIDES

Session 4

Mr. Andrew JJ Burrow
DHV International

Tel: (876) 940-3423/4447
Fax: (876) 940-2619
Email: burrow@cwjamaica.com

Session 11

Ms Heather McFarlane
Construction Resource and Development Centre

Tel: (876) 940-2933-4
Fax: (876) 940-2935
Email: crde@jol.com.jm

Session 11

Ms Karen Michell
Sanitation Support Unit
Paradise Norwood
PO Box 417
Montego Bay
St James

Tel: (876) 940-2933-4
Fax: (876) 940-2935
Email: crde@jol.com.jm

5

APPENDIX 3

LIST OF
COUNTRY REPRESENTATIVES

6

ARUBA
BELIZE

Dr Ing. Elton L. Lioe-A-Tjam
Mr. Jose Mendoza
Director
Environmental Officer
Directorate VROM
Ministry of Natural Resources and the
Government of Aruba
Environment
Wayaca 31-C
Department of the Environment
Oranjestad
10/12 Ambergis Avenue
Aruba
Belmopan, Cayo District

Belize
Tel: 297-832345

Fax: 297-832342

Email: vromaua.dir@setarnet.aw
Tel: 501-8 22816/22542

Fax: 242-322-5080

Email: envirodept@btl.net
BAHAMAS

Ms Christal Francis
BRITISH VIRGIN IS LANDS
Water & Sewerage Corporation

PO Box N-3905
Mr. Mukesh Ganesh
Nassau
Engineer
Bahamas
Water & Sewage Department

Min. of Communications & Works
Tel: 242-323-7474 ext. 5738
PO Box 130
Fax: 242-322-5080
Roadtown, Tortola

British Virgin Islands

BARBADOS
Tel: 284-494-3416/7 ext. 5797

Fax: 284-494-6746
Mr. Anthony S. Headley
Email: water@caribsurf.com
Acting Deputy Chief

Environmental Engineer

Environmental Engineering Division
COLOMBIA
Ministry of Health & Environment

Culloden Farm, Culloden Road
Dr Serigo Alberto Cruz Fierro
St Michael
Funcionario
Barbados
Direccion Tecnica de Desarrollo Sostenible

Ministerio del Medio Ambiente
Tel: 246-436-4820/6
Calle 37 No. 8-40
Fax: 246-228-7103
Santafe de Bogota
E-mail: msquared@surf.com
Colombia

Tel: 57-1 338-3900 ext. 430-429

Fax: 57-1 288-9725

Email: cruzser@hotmail.com

7

CUBA
MEXICO

Ms Carmen C Terry Berro
Dr Felipe Arreguin Cortes
Specialist
Coordinador
Environmental Agency
Tratamiento y Calidad de Agua
Ministry of Science, Technology and Environment
Instituto Mexicano de Tecnologia del Agua
Calle 20 Esquina 18A
(IMTA)
No. 4110, Playa
Paseo Cuauhuahuac 8532
Ciudad de la Habana
Jiutepec, Morelos, C.P. 62550
Cuba
Mexico
Tel: 537-229351/296014

Fax: 537-249031
Tel: 52-73-194381
Email: cterry@cigea.unepnet.inf.cu
Tel: 52-73-194000 ext. 543

Fax: 52-73-194381

Email: areguin@tlaloc.imta.mx
HAITI

Pierre Daniel Carlo Lafond
NETHERLANDS ANTILLES
Directeur General

Ministere de L'Environnenment
Mr. Patricio D Oleana
181 Haut Turgeau
Department of Public Works (DOW)
P-AU-P
Subdivision Sanitary Engineering
Haiti
Head Mechanical and Electrical Engineering

Punta Mateo K3 Jankock
Tel: 509-45 0635/45 7585/45 7572
Curacao
Fax: 509-45 7360/45 1022
Netherlands Antilles
Email: dg.mde@rehred.haiti.net

Email: dg.mde@palaishaiti.net
Tel: (599-9) 868-6866

Fax: (599-9) 868-6866

Email: curzuiv@cura.net
JAMAICA

Mrs Ianthe Smith
Mr. Arthur Rodriguez
Senior Director
Depart. of Public Works (DOW)
Pollution Control
Subdivision Sanitary Engineering
Natural Resources Conservation Authority
Head Process Engineering
531/2 Molynes Road
Landhuis Parera
Kingston 10
PO 3227
Jamaica
Curacao, N.A.

Tel: 876-923 5125
Tel/Fax: (599-9) 868 6866
Fax: 876-923 5070
Tel: (599-9) 433-4444 (Head Office)

Fax: (599-9) 461-7969 (Head Office)

Email: curzuiv@cura.net

8

ST KITTS AND NEVIS
TRINIDAD AND TOBAGO

Mr. Errol Rawlins
Mr. Khansham Kanhai
Deputy Chief Environmental Health Officer
Technical Advisor
Ministry of Health
Ministry of Public Utilities
Environmental Health Department
Government of Trinidad & Tobago
Church Street
16-18 Sackville Street
Basseterre
Port-of-Spain
St Kitts
Trinidad

Tel: (868) 624-9068
Tel: (869) 465-2521 ext. 1271
Fax: (868) 625-7003
Fax: (869) 465-1316
Email: kkanhai@tstt.net.tt

Email: kappa@cariblink.net

ST LUCIA

UNITED STATES OF AMERICA
Mr. Errol Frederick

Sewerage Operations Manager
Mr. Louis Salguero
Water and Sewerage Authority
United States Environmental Protection Agency
Lanse Road
(U.S. EPA)
Castries
980 College Station Road
St Lucia
Athens

Georgia 30605
Tel: 758-452-5344 ext. 102

Fax: 758-452-6844
Tel: (706) 355-8732

Fax: (706) 355-8744

Email: salguero.louis@email.epa.gov
ST VINCENT & THE GRENADINES

Mr. Brian George
VENEZUELA
Engineer

Central Water and Sewerage Authority
Ing. Fanny Rodriquez
New Montrose
Jefe, Division de Calidad Ambiental
PO Box 363
Ministerio del Ambiente
Kingston
Av. Carlos Sanda c/c Delicias
St Vincent & the Grenadines
Edif. Capri Apto. 501

Valencia, Venezuela
Tel: 784-4562946 ext. 212

Fax: 784-4562552
Tel: 5841-315748
Email: cwsa@caribsurf.com
Fax: 5841-674376

Email: Lansdell@telcel.net.ve

9

APPENDIX 4

LIST OF OTHER PARTICIPANTS

11

ANGUILLA
FRANCE (GUADELOUPE)

Mr. Stephenson Roger
Mr. Eric Muller
Principal Environmental Health Officer
Direction Regionale de l'Environement de
Primary Health Care Department
Guadeloup
Ministry of Health
Alle des Louriers, Circunvallation
The Valley
PO Box 105
Anguilla
97100 Basse-Terre

Guadeloupe
Tel: 264-497-2631/3763

Fax: 264-467-5486
Tel: (590) 99 35 60

Fax: (590) 99 35 65

Email: diren971@outremer.com
ANTIGUA AND BARBUDA

Mr. David Matthery
JAMAICA
Senior Public Health Inspector

Central Board of Health
Mr. Howard Batson
C/- Ministry of health
U.S. AID
All Saits Road, St John's
2 Haining Road
Antigua & Barbuda
Kingston 5

Jamaica
Tel: (268) 462-2936/1891

Fax: (268) 460-5992
Tel: (876) 926-3781

Fax: (876) 929-9944

CANADA
Mr. Bruce Excell

Waste Technology
Mr. Jean-Pierre Dube
1 Riverbay Road
Option Environment
Montego Bay
2360 Ave. Lasalle, bwuau 202
Jamaica
Montreal (Quebec) HIV 241

Canada
Tel: (876) 979-5756

Fax: (876) 940-4265
Tel: (514) 257-6380

Fax: (514) 257-6382
Ms Stephanie M Fletcher
Email: jpdube@opt.env.qc.ca
Ministry of Health

St Mary Health Department

Port Maria P.O.

St Mary
COMMISSION OF THE EUROPEAN

UNION
Tel: (876) 994-2358

Fax: (876) 994-2643
Mr. Peter Collins

Water Expert
Ms Grace Foster-Reid
European Commission
Alcan Jamaica Company
EC Delegation
Kirkvine PO
8 Oliver Road
Manchester
PO Box 463
Jamaica
Kingston 8

Jamaica
Tel: (876) 961-7144

Fax: (876) 961-7822
Tel: (876) 924-6333
Email: grace@cwjamaica.com
Fax: (876) 924-6339
Email: grace-foster-reid@alcan.com
Email: eudeljam@wtjam.net

12

Ms Ining Hsu
Mr. Rinav Mehta
St Mary health Dept/U.S. Peace Corps
Environmental Control Division � MOH & U.S.
1A Holborn Road
Peace Corps
Kingston 10
1A Holborn Road
Jamaica
Kingston 10

Jamaica
Tel: (876) 929-0495 (Peace Corps)

Tel: (876) 994-2358 (Office)
Tel: (876) 967-1100-7 ext. 2220
Fax: (876) 994-2643 (Office)
Fax: (876) 967-1280

Email: reendog@kasnet.com
Mr. Maurice Jones

Fluid Systems Engineering Ltd
Mr. Malden Miller
27 Harbour Street
Montego Bay Marine Park Trust
Kingston
Pier 1, Howard Cooke Blvd.
Jamaica
Montego Bay PO #1

St James
Tel: (876) 922-6670
Jamaica
Fax: (876) 922-7512

Email: mojoe@cwjamaica
Tel: (876) 952-5619

Fax: (876) 940-0659
Mr. Matthew Krachon
Email: mbmp@n5.com.jm
St Thomas Health Dept/U.S. Peace Corps

1A Holborn Road
Mr. Errol Mortley
Kingston 10
Urban Development Corporation
Jamaica
17 Ocean Boulevard

Kingston Mall
Tel: (876) 982-1619
Kingston

Jamaica

Mr. Desmond Malcolm
Tel: (876) 922-8310-4 ext. 2937
National Water Commission
Fax: (876) 929-9944
4 Marescaux Road
Email: hsaddler@usaid.gov
Kingston 5

Jamaica

Tel: (876) 906-9020
Mr. Cliff Reynolds
Fax: (876) 906-9019
Negril Chamber of Commerce

Box 31 Negril P.O.

Westmoreland
Mr. Donald D McDowell
Jamaica W.I.
Ministry of Environment and Housing

2 Hagley Park Road
Tel: (876) 957-4067
Kingston
Fax: (876) 957-4591
Jamaica
Email: negrilchamber@cw.jamaica.com

Tel: (876) 926-1590-9 ext. 2126

Fax: (876) 926-8535
Mr. Herrol Sadler

U.S. AID

2 Haining Road

Kingston 5

Tel: (876) 926-3645-9

Fax: (876) 929-9944

Email: hsaddler@usaid.gov

13

Mr. Gangolf Schmidt
Mr. Brad Walker
GTZ
U.S. Peace Corps
C/- SRC
1A Holburn Road
PO Box 350
Kingston 10
Kingston 6
Jamaica
Jamaica

Tel: (876) 906-4186
Tel: (876) 919-4117/927-1771
Email: bawalker@ns.com.jm
Fax: (876) 977-2194

Email: srcgtz@cwjamaica.com

Mr. Dean S Williamson

National Water Commission
Mr. David Steen
PO Box 474
U.S. Peace Corps
Bodue Industrial Estate
1A Holburn Road
Montego Bay
Kingston 10
St James
Jamaica
Jamaica

Tel: (876) 978-4061
Tel: (876) 952-1640/952-8344
Fax: (876) 978-4062
Fax: (876) 979-6090
Email: crdc@jol.com.jm
Email:dwllnson@nwc.com.jm

Ms Heather Storrud
Ministry of Health/ECD and U.S. Peace Corps
1A Holborn Road
Kingston 10
Jamaica

Tel: (876) 967-1100 ext. 2229
Email: ecd@epi.org.jm

Roger Surtees
International Consultant
Thames Water Int. Consultancy
NWC Bogue Ind. Estate
Montego Bay
Jamaica

Tel: (876) 952-1640
Fax: (876) 971-6204

Mr. Winston Thomas
Pan American Health Organization (PAHO)
Oceana Building
2-4 King Street
Kingston
Jamaica

Tel: (876) 967-4626/4691
Fax: (876) 967-4187
Email: wthomas@jam.paho.org

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Appendice 5
Institutional Profiles

THE CARIBBEAN ENVIRONMENT PROGRAMME
Established by the nations and territories of the Wider Caribbean Region in 1981, the Caribbean
Environment Programme (CEP) promotes regional cooperation in the protection of the marine
and coastal environment. The CEP is an integral part of the Regional Seas Programme of the
United Nations Environment Programme (UNEP), and is administrated by its Regional
Coordinating Unit (CAR/RCU) in Kingston, Jamaica.
The legal framework for the CEP is provided by the Cartagena Convention that was adopted in
1983. This Convention, the only region-wide environment treaty, is a framework agreement
setting out the political and legal foundations for environmental actions to be developed. These
actions are directed by a series of operational Protocols, addressing oil spills, protected areas and
wildlife (SPAW Protocol), and land-based activities and sources of marine pollution (LBSMP).
The CEP helps to protect the marine and coastal environments of the Wider Caribbean Region
through its catalytic and facilitating role. This is accomplished through programmes that
strengthen national and subregional institutions, stimulate technical co-operation among
countries and by the creation of networks of information and people. The various programmes
and activities of the UNEP-CAR/RCU assist the nations of the Wider Caribbean Region to chart
a course for sustainable development and environmentally sound practices. The CEP assists in
the co-ordination of International Year of the Ocean and has established co-operation with global
agreements such as the Convention on Biological Diversity.
The Programme co-ordinates the collection, production, reviews and dissemination of studies,
publications and the results of work performed under its aegis. From technical reports, to
newsletter, to educational and awareness-raising materials, to technical protocols and
agreements, the CEP organizes and hosts many seminars and workshops. These events bring
together non-governmental organisations, environmental specialists, scientists, policy makers
and others, including representatives of CEP member governments.
The activities of the CEP have been developed to support the implementation of the Cartagena
Convention and its Protocols. In this capacity, the CEP has been co-ordinating activities
regarding the conservation and management of endangered species and habitats of regional
concern, the establishment and management of the protected areas, and the assessment,
management and monitoring of land-based sources of marine pollution. The Programme has
developed guidelines for best available technologies and practices for sewage and agricultural
waste management, as well as oil spills contingency plans. Systematic assistance is also provided
on integrated coastal area management through the promotion and application of regional
guidelines. Other major activities are the promotion of best environmental management practices

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in the vital tourism industry of the Wider Caribbean and the creation of a network of marine
protected areas.
The CEP is also assisting with the development of a regional network of marine and coastal
information and data through the Internet. Databases on government and regional contracts,
experts, and projects are maintained. Additionally, the programme develops geographic
databases on relevant subjects, such as marine protected areas and endangered species.
The public is kept informed of the environmental activities in the Wider Caribbean through the
publication of the CEP newsletter, CEP news, and its dynamic Internet Web site. The
Programme is an important instrument for increasing public awareness, environmental education
and capacity building through training and the publication of documents and materials.
The members of the CEP are the countries and territories bordering the Caribbean Sea, the Gulf
of Mexico and adjacent portions of the Atlantic Ocean, south of 30� North latitude and within
200 nautical miles of the Atlantic Coast. This area, known as the Wider Caribbean Region,
includes all the islands of the Caribbean, the North and Central American countries bordering the
Gulf of Mexico and the Caribbean Sea, and the northern South American countries as far east as
French Guiana. This region is a complex mix of peoples, languages and societies in one of the
most culturally and ecologically diverse areas of the world.
The CEP also works closely with numerous organizations in protecting the Wider Caribbean
marine and coastal environments. The Programme is primarily funded by the Governments of the
region through the Caribbean Trust Fund. Additionally funds are provided by other governments,
donor agencies and UNEP.
As an office of UNEP, the CAR/RCU co-operates with Regional Seas Programme and other
UNEP initiatives, as well as many organizations of the UN system. International, regional and
local non-governmental organizations, as well as academic and research institutions, participate
in the many projects of the CEP and assist with their implementation.
More accessible and comprehensive information is available on the CEP web site,
http://www.cep.unep.org/. This site provides further detailed information about CEP activities,
office and staff. More importantly, the site also makes available to the world our library of
technical reports, our quarterly newsletter, project update pages, environmental databases and
directories, and links to other Internet resources.

THE ENVIRONMENTAL TECHNOLOGY CENTRE AT MURDOCH UNVERSITY IN
WESTERN AUSTRALIA
The environmental Technology Centre (ETC) at Murdoch University was established in 1992,
and officially inaugurated in 1994 during the National Conference on Technology Transfer in
Remote Communities. The ETC was established by the Remote Area Developments Group of
the Institute for Environmental Sciences at Murdoch. The aim of the ETC is to research, develop

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and demonstrate environmental technologies, conduct education and training, provide
consultancy services to industry, and raise community awareness of environmental technologies.
Its facilities are open to local industries wishing to test and monitor products within the
university infrastructure.
The ETC occupies a 1.7 hectare site on the Murdoch University campus at which thirty-two
environmental technologies have been combined to form an integrated operating demonstration
system. The technologies used and researched at the site include climate-sensible buildings,
renewable energy systems for power supply and water pumping, aquaculture systems, organic
waste management, and permaculture. The integrated approach allows research to be carried out
on the important interactions between different technologies, rather than just the effect of a
single technology. This gives the ETC a considerable advantage over other research institutions
which focus on single technologies in relative isolation. The ETC is able to offer holistic and
flexible solutions to human needs.
The ETC's focus is on small-scale environmental technologies, which are cheap to produce and
establish, robust, efficient, and easy to operate and maintain. The aim of this is to maximise the
opportunities for user communities to "own" the technology, resulting in greater and more
sustained uptake of the technology, higher levels of community awareness and involvement, and
ultimately a more successful operation. This approach has been successful in remote areas in
Australia, and is highly applicable to communities in developing countries, as well as to urban
communities worldwide, particularly when applied in collaboration with industry and
government.
The ETC has a strong track record of research collaboration and consultancy work with industry
and government organisations. It has also established connections with the international
environmental research community through its association with the United Nations
Environmental Program. The growth and development of the ETC, and the increased value it can
thereby offer to local industry, depend upon consolidating and extending these international
links.
The ETC at Murdoch University is affiliated with UNEP-IETC as an international centre for the
Asia-Pacific Region.

Remote Area Developments Group (RADG)
The RADG was established in the Institute for Environmental Science at Murdoch University in
1985. Its aims are to investigate the problems of small communities in remote areas of Australia,
and to develop appropriate technologies to solve those problems and improve the living
conditions for people in those communities. Some keyareas of research and development include
appropriate technology for water supply and sanitation, revegetation, bush food and
communications. The RADG Advisory Committee consists of industry and community
representatives.

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The RADG established the ETC in order to provide an appropriate research and teaching
location for integrated environmental technologies, and to educate and inform the public about
environmental issues facing remote communities in Australia. The ETC's activities have
expanded since its establishment to include research into application of environmental
technologies to developing countries and urban communities as well as remote areas. The RADG
is the specific research group associated with the ETC, but the Centre's staff also develop and
work on projects not directly linked to the RADG.

Institute for Environmental Science
The RADG and the ETC are key components of the Murdoch University-based Institute for
Environmental Science, which was set up in 1977 to foster links between university research and
industry. The Institute is based in the Division of Science at Murdoch University alongside the
School of Environmental Science, one of the few schools nationally to focus specifically on
teaching and research in environmental science. The aim of the Institute is to draw staff from the
School into industry-focussed research. Its expertise in marine environments, land-based studies
and air pollution has been used to solve industries' environmental problems, and to provide
specialist training for government and industry agencies.

Australian Sustainable Development Centre
The ETC will be part of the proposed new Australian Sustainable Development Centre (ASDC)
to be established on the Murdoch University campus. This new initiative will link a range of
institutions in Western Australia with complementary interests in sustainable development,
including the applications of renewable energy, energy efficiency, water and wastewater
systems, ecological health, indoor environments, solid waste recycling, transport, city planning,
land care and the social aspects of sustainability. Participants in the ASDC will include:
� Environmental Technology Centre (ETC), through the Remote Area Developments
Group (RADG);
� Waste Management;
� Australian Cooperative Research Centre for Renewable Energy (ACRE);
� Institute for Science and Technology Policy (ISTP);
� International Centre for Application of Solar Energy (CASE); and
� Murdoch University Energy Research Institute (MUERI).

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By integrating and acting as a shop front for these organisations, the ASDC will provide
opportunities for increasing research, teaching/training and consulting, with a focus on the
international market and the WA regions, as well as across Australia. It is also seen to be an
incubator for further industry co-location opportunities at Murdoch. The ETC will bring
considerable value to the ASDC through its link with the UNEP and its established track record
in integrated environmental technology research. In turn, it will benefit from the synergy
provided by the interaction of a range of institutions engaged in environmental research and
development.

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