SANITATION
for small islands
Guidelines for
Selection and
De
D r
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k D
e
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Development
Compiler
SOPAC Miscellaneous Report 250
September 1997
Bi
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Depledge, D. (Comp.) 1997: Sanitation for Small Islands: Guidelines for selection
and development. SOPAC Miscellaneous Report 250. SOPAC Secretariat. iv, 28 pages.
September 1997
ISBN: 9822070071
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SOPAC Secretariat
Private Mail Bag, GPO
Suva, Fiji
Phone: (679) 381377; Fax: (679) 370040
E-mail: postmaster@sopac.org.fj
SANITATION
for small islands
Guidelines for
Selection and
Development
Compiled by
Derrick Depledge
Published by the
South Pacific Applied Geoscience Commision (SOPAC)
in conjunction with the United Nations Development Programme
and in collaboration with the World Health Organisation
September 1997
A PROFILE
SOUTH PACIFIC APPLIED GEOSCIENCE COMMISSION
SOPAC is a Pacific, regional, intergovernmental organisation
Me
M m
e b
m e
b r
e
r C
o
C u
o n
u t
n r
t i
r e
i s
e
s a
n
a d
n
d N
a
N t
a i
t o
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o a
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e
R p
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p e
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e e
s n
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e :
s
with 17 member countries. SOPAC assists its island
Australia: Assistant Secretary, Office of Pacific Island Affairs, Department of Foreign
member countries with the sustainable development of
Affairs and Trade, Canberra ACT 2600
their physical environment and non-living resources
Cook Islands: Secretary, Ministry of Marine Resources, PO Box 85, Rarotonga
through the application of geoscience, giving members
Federated States of Micronesia: Minister, Department of Resources & Development,
access to modern equipment, an extensive database and
Box 12, Palikir, Pohnpei
experienced marine scientists.
Fiji: Director of Mineral Development, Mineral Resources Department, Private Mail
Ac
A t
c i
t v
i i
v t
i i
t e
i s
e :
s
: SOPAC's annual work program is dependent on
Bag, GPO, Suva
members' requests, funding and the expertise available to
French Polynesia, Special Advisor to the President, PO Box 2551, Papeete
the Secretariat at the time. The range of activities includes:
studies of geological processes and hazards; resource
Guam: Director, Bureau of Planning, PO Box 2950, Agana 96910
studies for environmental management and coastal
Kiribati: Secretary, Ministry of Natural Resources Development, PO Box 64, Bairiki,
development; assessment of indigenous energy and mineral
Tarawa
potential; coastal and seabed mapping; water resource and
Marshall Islands: Secretary for Foreign Affairs, Ministry of Foreign Affairs, PO Box 2,
sanitation and training in geosciences. These are
Majuro MI 96960
incorporated under SOPAC's four major programs:
New Caledonia: Service des Mines et de l'Energie, BP465, Noumea
Resource Development, Environmental Geoscience,
National Capacity Development and Corporate Services.
New Zealand: Ambassador to Fiji, New Zealand Embassy, PO Box 1378, Suva
Pu
P b
u l
b i
l c
i a
c t
a i
t o
i n
o s
n :
s SOPAC News (newsletter); range of technical
Niue: Assistant Head of External Affairs, Premier's Department, PO Box 67, Alofi
Pu
P b
u l
b i
l c
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a i
t o
i n
o s
n :
s
reports for member countries; proceedings of the annual
Papua New Guinea: Secretary, Department of Mining and Petroleum, Private Mail Bag,
meeting, SOPAC Projects (non technical summaries of
Port Moresby
work), and others. For more information contact
Solomon Islands: Permanent Secretary, Ministry of Energy, Water and Mineral
Resources, PO Box G37, Honiara
Tonga: Permanent Secretary, Ministry of Lands, Surveys and Natural Resources, PO Box
The Director
5, Nuku'alofa
Private Mail Bag, GPO, Suva, Fiji
Tel: (679) 381377, 381139, 381251
Tuvalu: Secretary to Government, Secretary of Foreign Affairs, Office of the Prime
Minister, Funafuti
Fax: (679) 370040, 384461
email: postmaster@sopac.org.fj
Vanuatu: Director, Department of Geology, Mines and Water Resources, Private Mail
World Wide Web site: http://www.sopac.org.fj
Bag 001, Port Vila
Western Samoa: Secretary for Foreign Affairs, GPO Box L1861, Apia
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TABLE OF CONTENTS
ACKNOWLEDGEMENTS ............................... i
v
3.5 Ventilated improved pit latrines ................... 11
3.6 Composting toilets ............................ 12
1. INTRODUCTION ................................... 1
3.7 Aqua privies ................................. 13
1.1 What is sanitation? ............................. 1
3.8 Pour flush latrines ............................. 14
1.2 Why do we need sanitation? ...................... 1
3.9 Septic tanks ................................. 14
1.3 What are the particular problems of small islands? ........ 3
3.10 Sewered systems ............................. 16
2. THE NEED TO COMMUNICATE
4. MAKING THE CHOICE .............................. 18
2.1 Involving the community ......................... 5
2.2 Health, hygiene and sanitation promotion ............. 6
5. TRIALS AND DEVELOPMENT .......................... 20
3. DESIGN OPTIONS
6. FINAL THOUGHTS ................................. 21
3.1 Open defecation .............................. 8
3.2 Overhung latrines .............................. 9
7. SOME SOURCES FOR FURTHER READING ................ 22
3.3 Bucket latrines ............................... 10
3.4 Simple pit latrines ............................. 10
8. TECHNICAL TERMS ................................ 23
(ii
( i
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ii
i
ACKNOWLEDGEMENTS
The contents of this booklet are based largely on the findings of the
rial panel appointed by the World Health Organisation (WHO) are grate-
SOPAC Workshop on "Appropriate and Affordable Sanitation for Small Is-
fully acknowledged for reviewing the manuscript and that of the compan-
lands" held in Tarawa, Kiribati from 6-8 August 1996. The Workshop was
ion report Design Examples of Waterless Composting Toilets (SOPAC Mis-
organised by SOPAC's Pacific Water and Sanitation Program. The contribu-
cellaneous Report 249). Special thanks go to Sara Wood and Roland
tions of all those who attended that workshop are gratefully acknowledged.
Schertenleib of WHO.
For constructive comments and the lending of their expertise, the edito-
(iv
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iv
i
1. INTRODUCTION
Although this paper was prepared for use in small islands, it provides a
In more practical terms sanitation has been defined as:-
useful introduction to issues and options applicable in many other situa-
The means of collecting and disposing of excreta and community liquid
tions.
waste in a hygienic way so as not to endanger the health of individuals or
One of the basic facts of life is that all people need to get rid of waste
the community as a whole (Franceys et al, 1992).
matter every day. The technical term for this waste is excreta, which con-
sists of faeces, (solid matter), and urine, (liquid matter). See page xx for
other technical terms used in this booklet.
This booklet has been prepared to give some background and provide
1.2 WHY DO WE NEED SANITATION?
some guidelines on sanitary ways of dealing with excreta in the small is-
lands of the Pacific. It is aimed at helping both those considering providing
and those considering upgrading their sanitation facilities.
He
H a
e l
a t
l h
t
h A
s
A p
s e
p c
e t
c s
t
As the dictionaries point out sanitation and health are closely intertwined.
A lack of good sanitation and hygienic behaviour puts all people at risk
of diseases and epidemics , and is a cost to all society, both rich and poor.
1.1 WHAT IS SANITATION?
Sanitation is the first barrier against diseases associated with human waste.
A sanitary environment is a human right and necessary for human dignity.
Dictionaries regard sanitation as a general word for the protection and
Good sanitation must, therefore provide a barrier to the transmission of
improvement of health.
disease, either by destroying pathogens, or effectively isolating them from
human contact.
For example:
If the disposal of human faeces and urine in a community is insanitary
and inadequate to protect health, then the sanitation facilities need to be
Protection of health by maintenance of sanitary conditions (We
W b
e s
b t
s e
t r
e ).
improved.
The improving of public health especially by efficient drainage and dis-
If the sanitation facilities are inadequate:-
posal of sewage (Ne
N l
e s
l o
s n
o
n C
o
C n
o t
n e
t m
e p
m o
p r
o a
r r
a y
r
y E
n
E g
n l
g i
l s
i h
s
h D
i
D c
i t
c i
t o
i n
o a
n r
a y
r ).
· humans, rodents and other animals can spread disease by spreading
Improvement of conditions aimed at helping, (or not impeding) the pro-
faeces
tection of health against dirt and infection (Ox
O f
x o
f r
o d
r
d P
o
P c
o k
c e
k t
e
t D
i
D c
i t
c i
t o
i n
o a
n r
a y
r ).
· flies can breed freely on the faeces and transmit diseases, and
· the ground and water supplies will be contaminated.
1
Pathogens
Viruses are transmitted as inert particles that are unable to replicate outside a living host. These
particles, or virons, have the ability to cause disease in people who ingest them with drinking water
Most diseases are caused by a PATHOGEN, a biological agent. There
or contaminated food. Over 100 types of viruses have been isolated from faecal material. Viral
are four types of pathogen:-
particles lose their infectivity with time. The length of time varies with viral types. Routes of viruses
include through the ground into the water table, and via contaminated food, fingers and flies. Ex-
creted viruses have low infectious doses (<100).
1.
1
. e
g
e g
g s
g
s o
f
o
f h
e
h l
e m
l i
m n
i t
n h
t s
h
s (
w
( o
w r
o m
r s
m )
s
Examples of worm infections
organisms
Faecal material can contain 1,000,000 viruses/gram in the excreta of an infected individual.
ascariasis, (roundworm)
Ascaris lumbricoides
trichuriasis, (whipworm)
Trichuris trichiura
Shigellosis, Hepatitis A and Typhoid are more likely to outbreak in un-
2.
2
. p
r
p o
r t
o o
t z
o o
z a
o
treated groundwater systems than surface water systems. Whereas giardia-
Examples of protozoal diseases
organisms
sis, viral gastroenteritis, salmonellosis and chemical poisoning are more likely
amoebic dysentery
Entamoeba histolytica
to occur in surface water systems, (Canter et al, 1988).
giardiasis
Giardia lamblia
Many of the climatic and lithological features of tropical sand and coral
islands, create conditions which favour the extended survival and subsur-
3.
3
. b
a
b c
a t
c e
t r
e i
r a
i
face transport of enteric bacteria and viruses. An exception is the preva-
Examples of bacterial diseases
organisms
lence of high temperatures which accelerate the attenuation of these mi-
Cholera
Vibrio cholerae
croorganisms in the subsurface, (Dillon, 1996).
Typhoid fever
Salmonella typhi
Paratyphoid fever
Salmonella paratyphi
Bacillary dysentery
Shigella
Diarrhoeal disease
E coli, Salmonella, Campylobacter spp
Nitrogen
The median infectious dose for bacteria is typically 10 000 or more. Bacteria are able to multiply
In addition to pathogens, excreta produces a number of chemical sub-
outside their host.
stances which can find their way into the natural environment. From a
health point of view the most serious of these is Nitrogen, N, which may
Faecal material can contain as many as 1 000 000 000 bacteria/gram in the excreta of an infected
cause a condition known as blue baby syndrome, if water with high Ni-
individual.
trate-content is ingested by young bottle fed babies.
4.
4
. v
i
v r
i u
r s
u e
s s
e
It has been estimated that each person produces about 8 kg of nitrogen
Examples of Viral Diseases
organism
each year in excreta, which can contribute significantly to high levels in
Infectious hepatitis
hepatitis A
natural water systems. The limit recommended by the World Health Or-
Poliomyelitis
poliovirus
ganisation, (WHO), is 10 mg/l nitrate-nitrogen for water used for drinking.
Diarrhoeal diseases
rotavirus and others
2
En
E v
n i
v r
i o
r n
o m
n e
m n
e t
n a
t l
a
l A
s
A p
s e
p c
e t
c s
t
fore potentially a product of value. Composting toilets, which are described
later in this booklet, provide a technology which converts human excreta
into a useful product, and at the same time eliminates any discharge into
Coastal Water Resources
the natural water system as well as the need of water to carry excreta away.
Globally, land-based pollutants contribute 75% or more of all pollutants
entering the oceans.
Sewage is one of the most significant source of marine pollution in the
1.3 WHAT ARE THE PARTICULAR
Pacific region. On the smaller islands, the source is raw or partially treated
sewerage flowing from latrines and privies, and water seal toilets.
PROBLEMS OF SMALL ISLANDS?
For the larger population areas the conventional approach to sanitation
is to install a "proper disposal system", that is to use water to carry excreta
Atolls and small island nations have unique needs in terms of sanitation.
out of sight. Even if the effluent is treated this simply results in the problem
Some of the specific problems relate to:-
shifting from one place to another, often to the ocean or lagoon.
· small land area
Critical environmental problems which can occur are the development
· fragile ground water systems
of algal blooms, eutrophication in lagoons and dying reefs.
· increasing population density
· lack of income to pay for improvements
It is necessary first of all to define "small" as applied to an island. Some
Freshwater Resources
very small islands, or cays, can be less than 200 m in diameter or width,
On coral and other small islands, and in coastal areas of larger islands
with little vegetation, probably no ground water, and generally without a
contamination by sewage can impair the beneficial uses of freshwater re-
population.
sources, including the ecosystems which are supported by such surface or
Small islands up to 2000 km2 may be of low elevation, with shallow
ground water.
ground water and population densities varying from very low to very high.
In particular, where population densities are high there is a risk to the
Where the population is small there may be no need for any upgrading
natural water systems of microbiological and nitrate and other nutrient con-
of sanitary arrangements. Traditional defecation practices such as using iden-
tamination, which can have a serious and recurrent effect on local com-
tified areas of bush or beach may be sufficient to ensure reasonable protec-
munities.
tion of health from communicable diseases. But populations are generally
increasing in the Pacific and with this increase, the risk to health from inad-
equate sanitation is also increasing. This is particularly noticeable in the
small atoll nations where urban drift has led to high population concentra-
The Resource Value of Human Excreta
tions in such places as Funafuti in Tuvalu, South Tarawa in Kiribati, and
Majuro and Ebeye in the Marshall Islands.
The idea of excreta as a resource rather than a waste needs to be pro-
moted in the Pacific region. Human excreta contains nutrients, and is there-
3
Where the groundwater table is shallow, bacteriological and chemical
Many small islands have enclosed or partly enclosed lagoons in which
quality quickly deteriorates as a result of poor excreta disposal in areas of
the residence time of the water is quite long. These lagoons receive efflu-
population concentration such as villages. Lifuka in the Ha'apai Group of
ent via runoff or from groundwater seepage and can deteriorate in quality
Tonga is an example of this contamination of ground water resources,
rapidly.
(Furness,1996).
Another major problem, particularly for the more remote islands, is that
On higher islands, perhaps raised atolls such as Niue, the ground water
many people exist at the subsistence level and can contribute little to fi-
is at less risk because of the filtration capacity of the soil through which
nancing sanitation.
effluent from sanitary facilities has to pass.
4
2. THE NEED TO COMMUNICATE
A successful, sustainable sanitation system needs to be :-
Health education workers, preferably selected from the local commu-
nity, should be carefully chosen for their humility, commitment, sensitivity
· acceptable to the users,
and self confidence. They will need appropriate training, not only the tech-
· affordable for most people, and
nical aspects of health and sanitation, but also in the various methods of
· technically adequate.
communication.
It requires an open di
d a
i l
a o
l g
o u
g e
u
e between those wanting or needing the
Community leaders have an important role to ensure successful com-
sanitation facility and those who are able to advise on and assist with the
munity participation by encouraging people to come to meetings, arrang-
provision of such facilities.
ing meeting places and interpreting information.
To get the right balance between what is affordable, acceptable and
A Project Management Committee needs to be established. It should be
adequate will need a lot of two-way communication. The better this co-
representative of all groups within the community, particularly women but
operative approach progresses the better the result will be in terms of a
also including youth, church, village elders, local council, and teachers etc.,
sustainable sanitation development.
Information should be obtained from the community on their priority
wants and needs.
Participatory learning processes using simple language and practical dem-
onstrations is necessary for people to understand the need for change.
2.1 INVOLVING THE COMMUNITY
Communities should be informed of the various sanitation options and
given the opportunity to choose for themselves.
If improved sanitation is to be acceptable, it is essential to involve the
Monitoring and evaluation of the project, including the effectiveness of
community.
health education training is essential. Monitoring and evaluation should be
The community should be involved in the choice, construction, opera-
done jointly with the community, the Project Management Committee and
tion and maintenance of any sanitation facility. People must be consulted
the agency promoting the programme. It may be desirable to establish indi-
about their preferences.
cators to measure effectiveness as the project progresses.
They might need to be persuaded that sanitation improvements are
Appropriate compensation or remuneration for community health work-
needed, (see section 2.2 Health, Hygiene and Sanitation Promotion).
ers and others involved in the project should be arranged where possible.
Assistance in strengthening local capabilities for financial control and
If improved sanitation is to be introduced it must be affordable.
project management may be required.
Affordability should result in the best option for the money available. The
agreed sanitation option must be affordable to the majority of the local
Training of health workers and community health education sessions is
population, to those who are the target beneficiaries, and should be based
best carried out in the village or town setting of the project where there are
on the income of the poorer section of a community. Payments should not
opportunities to relate to real life local situations.
exceed 1-3% of the annual household income.
5
All financial resources should be looked at - local, government and ex-
2.2 HEALTH, HYGIENE AND
ternal.
SANITATION PROMOTION
When
people
start
living
close
together
in
villages
or
urban
areas
the
Th
T i
h n
i g
n s
g
s t
o
t
o c
o
c n
o s
n i
s d
i e
d r
e
need
for
sanitation
increases
if
health
problems
are
to
be
avoided.
People
will
need
to
be
made
aware
of
the
potential
danger
of
improper
The ideal sanitary facility for a small island may be too expensive, there-
excreta
disposal.
fore there will be a need to compromise.
There
will
be
a
need
for
stimulation
of
demand
for
sanitation
from
indi-
Financial input, however small, by the house-owners or villagers, is es-
vidual
householders.
sential if the facility is to be maintained in good condition. The chosen
Education
is
fundamental
to
the
sustainability
of
programmes.
Begin
design must improve the present position, and must be reproducible on a
with
mothers,
extend
to
the
school
curriculum
and
continue
into
the
com-
large scale.
munity.
The chosen design should be able to be upgraded when more finance
Community
elders
and
church
leaders
are
crucial
to
community
educa-
becomes available.
tion.
Programmes
should
be
cohesive
and
comprehensive
A range of options may be necessary for people with varying needs and
Health
education
is
a
combination
of
activities
undertaken
to
achieve
financial resources.
voluntary
behavioural
change
with
respect
to
the
use
and
benefits
of
water
Promotional costs, educational costs should be incorporated in the total
and
sanitation
facilities.
project costs.
Public
health,
general
health
and
hygiene
education
are
major
factors
in
Projects should be flexible enough to allow households to invest in on-
the
changing
of
people's
attitude
towards
sanitation.
site sanitation when they feel motivated and when they have the financial
It
is
not
simply
a
question
of
transmitting
educational
messages,
but
a
resources.
more
complicated
effort
at
modifying
human
behaviour.
6
Changes can be brought about by threat, incentive or as the conse-
The ideal form of education is person to person, one to one oral com-
quence of an epidemic.
munication. Most learning in small communities is from family members,
nurses and teachers.
Some custom beliefs restrict people from adopting good sanitary alter-
natives.
Village based workshops are a good strategy for most projects.
Public awareness and effective health education programmes are
Develop teaching methods and materials which can be taken into the
needed.
field, such as flip charts.
The motivation of communities and individuals is required.
Keep messages and drawings as simple as possible, one message at a
time.
The issues of health and status should be addressed through the various
media.
Prototype promotional material should be thoroughly pilot tested be-
fore being made widely available.
The written or spoken local language should be used wherever possi-
ble.
Money and time are needed to transmit the message regarding health
and hygiene to the entire population.
Illustrations should always depict local people rather than foreign fig-
ures.
7
3. DESIGN OPTIONS
If sanitation is to be introduced choose the right technology. It must be
· Local or imported housing material? Superstructure can be designed to
adequate for the local situation and needs.
suit local preferences and locally available materials. Not of major con-
cern in the design, although it must be acceptable to recipients.
Get the design right.
A list of the basic designs is given in the table at the end of Section 3,
Low cost sanitary waste disposal on small islands requires sensitive and
page 17, which gives an indication of the level of technology, the health
creative adaptations of existing designs.
risks, pathogen removal or containment, resource reclamation, relative costs
and constraints and advantages of each.
These designs are described in more detail below.
Av
A a
v i
a l
i a
l b
a l
b e
l
e T
e
T c
e h
c n
h o
n l
o o
l g
o y
g
The facility must be easy to build and maintain, and should require a
3.1 OPEN DEFECATION
minimum of off-island expertise or equipment.
BEACH OR BUSH
Some questions which must be addressed at an early stage are given
below. The answers will affect cost, the effect on the environment and the
effectiveness of the facility in bringing about health improvements.
In some Pacific islands there are no sanitation facilities. From a health
and hygiene point of view the worst case is where defecation is indiscrimi-
nate. Uncovered faeces can result in transmission of disease by flies, ani-
mals and people.
Questions
Defecation in designated areas is more acceptable, particularly where
· Squat or sit?
population density is low. If open defecation occurs in the bush, the faeces
should be covered. Designated areas of mangrove or beach can be used
· Water sealed or open, (visible)?
as long as there is a strong tide or current to flush the waste. It should be
· Water for flushing or no water, pour flush or cistern flush?
noted that most mangrove swamps have little current movement.
· Single or double chambers, pit, bucket, vault, aqua privy or septic tank?
Where people live closely together in compact villages or small urban
areas open defecation can be a danger to health and the environment, and
· Effluent seeps into the ground or to an outflow pipe?
alternative sanitation should be considered.
· Outflow to ground, or to soakaway trenches or to septic tanks or to ET
trenches or to a piped sewage system?
8
Open Defecation
islands of Tokelau, for example, there are many public over-water latrines,
which fulfil a social function as a meeting place where local news and views
Where there are no latrines people resort to
are exchanged.
defecation in the open. This may be indiscriminate
or in special places for defecation generally accepted
In Papua New Guinea, the overhung or `drop' latrine remains popular
by the community, such as defecation fields, rubbish
for villages sited on rivers, inlets or the ocean front. They are particularly
and manure heaps, or under trees. Open defecation
common in the stilt villages around Port Moresby, where they are described
encourages flies, which spread faeces-related
as odourless and breezy.
diseases.In moist ground the larvae of intestinal
In Micronesia in the 1970's the over-water "benjo" represented the state
worms develop, and faeces and larvae may be carried
of the art sanitary facility. These were conspicuous and often desecrated an
by people and animals. Surface water run-off from
otherwise pristine beach. They were also found over rivers and in man-
places where people have defecated results in water
groves. Today, they no longer exist, replaced largely by water-seal toilets.
pollution. In view of the health hazards created and
the degradation of the environment, open defecation
should not be tolerated in villages and other built-
up areas. There are better options available that
confine excreta in such a way that the cycle of re-
Source: Tearo, 1997
infection from excreta-related diseases is broken.
Overhung Latrine
A latrine is hung over
the sea, a river or
other body of water
into which excreta
3.2 OVERHUNG LATRINES
drop directly, is
known as an
Where people live near the sea, a river or other body of water excreta
overhung latrine. If
may be dispersed into the water by constructing a raised superstructure
there is a strong
current in the water
with a squat hole in the floor. A walkway is provided to reach this `over-
the excreta are carried
hung' latrine. These sanitation facilities are adequate if:-
away. Local
· the water is sufficiently deep
communities should
Source: WHO, (1991)
· the water is not still and currents carry away solids
be warned of the
danger to health
· the water is not used for recreation or fishing
resulting from contact with or use of water into which excreta have been discharged.
· the walkways are structurally safe
Advantages are that it my be the only feasible system for communities
living over water and it is cheap. The disadvantage is that there are
They are a common feature in some countries of the Pacific. In the
serious health risks associated with it.
9
"DRY" LATRINES
Many latrines do not use water to flush away excreta. Waste material is
allowed to drop directly through an open hole.
It should be noted that whilst this is good for conserving water resources,
some water is always needed for hand washing. If there is sufficient rainfall
the roof of a latrine can be used for collecting water for this purpose.
3.3 BUCKET LATRINES - "NIGHT SOIL"
The simplest form of latrine consists of a structure in which excreta are
Source: WHO, (1991)
collected in a bucket or container, which is periodically removed for dis-
posal or treatment.
Reusing human waste from these containers has been common in many
parts of Asia, where the product is treated as a valuable resource and is sold
at a price.
The technology is low cost, but is unhygienic in that spillages can easily
3.
3 4
.
4
S
I
S M
I P
M L
P E
L
E P
I
P T
I
T L
A
L T
A R
T I
R N
I E
N S
E
S W
I
W T
I H
T
occur in the transfer of the `night soil' into large containers and transported
ONE OR TWO PITS
to the disposal or treatment site.
The excreta may be used directly in the fields, it may be composted,
buried or used to fertilise fish ponds.*
A simple pit latrine can be constructed by digging a pit and placing a
slab with a squat hole over it. The latrine may have a superstructure for
In the Pacific some small towns and urban areas of PNG still use a `night
privacy.
soil' or sanitary pan system, with the excreta emptied untreated into the
environment.
Single pits have a limited life depending on their size and on the number
of people who use the latrine. Some pits can last as long as 15 to 20 years.
Double pits, requiring two cover slabs have the advantage of allowing each
pit to be emptied after two years of anaerobic digestion, which is usually
sufficient to kill off all pathogens. There is however no controlled process
taking place in the pit. This also allows rotation of the pits, giving the latrine
an indefinite life span. With a single pit the superstructure has to be relo-
*
cated once the pit is full.
N.B. Where the excreta is used directly onto fields or into ponds, there is a serious health
risk due to the possible transmission of pathogenic organisms which might be present in
human waste.
1 0
3.
3 5
.
5 V
E
V N
E T
N I
T L
I A
L T
A E
T D
E
D I
M
I P
M R
P O
R V
O E
V D
E
D P
I
P T
I ,
T
, (
V
( I
V P
I )
P ,
)
Simple Pit Latrine
LATRINES
This consists of a slab over a pit which may
be 2 metres or more in depth. The slab
With the addition of a vertical ventilation pipe, extending from the pit to
should be firmly supported on all sides and
at least 0.5 metres above the superstructure, and capped with fly-proof
raised above the surrounding ground so that
netting, the simple pit latrine can be made odourless, and can reduce the
surface water cannot enter the pit. If the
problem of flies.
sides of the pit are liable to collapse they
should be lined. A squat hole in the slab or
a seat is provided so that the excreta fall
directly into the pit. Its advantages are
its low cost, that it can be built by the
householder and that it needs no
water for operation. Disadvantages
Source: Intermediate Technology, 1991
Ventilated Improved Pit Latrine
are the considerable fly nuisance (and
Fly and odour nuisance may
mosquito if the pit is wet) unless there
be substantially reduced if
is a cover over the squat hole when the latrine is not in use. They can
the pit is ventilated by a pipe
also be quite smelly.
extending above the latrine
roof, with fly-proof netting
across the top. The inside of
the superstructure is kept
dark. Such latrines are
known as ventilated
Dry pits can also be formed by drilling 200 mm to 500 mm diameter
improved put (VIP) latrines.
holes to depths of about 10 metres.
Advantages are low cost,
These sanitation facilities isolate excreta from human or animal con-
can be built by
tact, but are not always effective in isolating insects, particularly flies. They
householder, needs no
often have an unpleasant odour and attract flies.
water for operation,
easily understood,
Children fear the darkness of the hole in the ground and are often
control of flies and the
dissuaded from using this type of latrine.
absence of smell in the
The simple dry pit also can pollute underlying ground water resources
latrines. Disadvantages
by the seepage of liquid effluent. However, this risk is minimal if the
are that it does not
groundwater level stays always at least one metre below the bottom of the
control mosquitoes, the
pit.
extra cost of providing
vent pipe and the need to
keep the interior dark.
Source: ??????
1 1
To create the air flow the defecation hole must be left open, the pipe
painted matt black to induce convective flow up the pipe, and the top of
the pipe located in clear air, away from shelter by buildings and trees.
An inlet to the toilet should be provided in the form of a vent at least
three times the size of the vent pipe. Wind speeds of 2m/s around the
structure should lead to air flows in the ventilation pipe of about 1 m/s.
Double pits allow the rotation of the pits and the use of the contents as
a soil conditioner when dug out after decomposition.
Pits can be sealed to protect any ground water resources, or can be
Source: Rybczynski et al. 1982
unlined allowing drainage of liquid effluent to the surrounding soil, where
no environmental problems are anticipated.
Composting Latrine
In this latrine, excreta falls into a watertight tank to which ash or vegetable matter
is added. If the moisture content and chemical balance are controlled, the mixture
PI
P T
I
T L
A
L T
A R
T I
R N
I E
N S
E
S -
- W
E
W T
E
will decompose to form a good soil condition in about four months. Pathogens are
killed in the dry alkaline compost, which can be removed for application to the land
as a fertiliser. There are two types of composting latrine; in one, compost is
A simple way to eliminate access by flies and to prevent odours is to use
produced continuously, and in the other, two containers are used to produce it in
a water seal. This, of course, requires a supply of water and leads to the
batches. The advantages are that a valuable humus is produced, water is
conserved and groundwater is protected from pollution. Disadvantages
need to dispose of liquid effluent in varying quantities.
are that careful operation is essential, urine has to be collected
separately in the batch system, and ash and vegetable matter nust be
added regularly.
3.6 COMPOSTING TOILETS
The ancient practice of using human excreta as a fertiliser has been
Composting toilets aim primarily at aerobic decomposition, which can
used for many centuries, particularly in Asia. The excreta is taken from the
be achieved in a shorter period of time. It has been called the dry conserv-
bins or containers and applied either directly to the soil or decomposed in
ancy method because no water is used in the toilets and the material is not
specially made pits or heaps. This removal and use of raw sewage repre-
disposed of to waste, as in other methods.
sents a health hazard. To overcome the problem and to retain the value of
For on-site aerobic treatment the requirements are :-
human excreta, designs have been made of latrines which store and com-
post the material in-situ.
· one or more containers
Dry pit latrines described in previous sections can produce a safe
· provision of a bulking agent, (vegetation) and/or separation of urine, to
composted material providing the excreta pile is kept untouched for up to
maintain a suitable carbon to nitrogen ratio for the microorganisms
two years to allow complete decomposition and die-off of pathogens.
1 2
· ventilation to provide the necessary oxygen for oxidation and heating of
the pile
The solid material is broken down by aerobic bacteria and other organ-
isms and the small amount of liquid waste drained to horizontal sealed
trenches, where it is disposed of by evapotranspiration. Alternatively the
urine can be separated from the solids before entering the pit diluted and
used as a nitrogenous fertiliser, or disposed of.
The solid material can be broken down rapidly into a soil like or leafy
material which has a pleasant earthy odour, if composted correctly.
Composting toilets need a supply of vegetation material handy to add
to the container regularly and a ventilation system which maintains a through
flow through the compost pile. A range of designs are available from pre-
fabricated units to home made latrines aimed at reducing costs. A detailed
description of designs and options is given in SOPAC Miscellaneous Report
249.
Source: WHO (1991)
Aqua Privies
3.
3 7
.
7 A
Q
A U
Q A
U
A P
R
P I
R V
I I
V E
I S
E
An aqua privy has a water-tight tank immediately under the latrine floor. Excreta
drop directly into the tank through a pipe. The bottom of the pipe is submerged in
Where water is in short supply the aqua privy design can be used. This
the liquid in the tank, forming a water seal to prevent escape of flies, mosquitoes
consists of a 100-150mm diameter chute or drop pipe placed below the
and smell. The tank functions like a septic tank. Effluent usually infiltrates into the
squat plate or latrine seat. Excreta drops through this chute directly into a
ground through a soakpit. Accumulated solids (sludge) must be removed regularly.
water-filled, sealed container. Excess fluid is dealt with via an overflow pipe
Enough water must be added to compensate for evaporation and leakage losses.
to a soak pit, a drainage trench or a sewer. The bottom of the drop pipe
The advantages does not need piped water on site and is less expensive
extends to 75mm below the liquid level. This provides a seal against escap-
than a septic tank. The disadvantages are that water must be available
ing gasses, and limits access by flies and mosquitoes.
nearby, that it is more expensive than the VIP or the pour-flush latrine
A bucketful of water is needed daily to clean the chute and maintain
and the fly, mosquito and smell nuisance is very real if the seal is lost
the fluid level. Regular removal of the sludge is required, which can be a
because there is insufficient water added. Also, regular desludging is
health hazard if not done carefully.
required - the sludge requiring careful handling and permeable soil is
required to dispose of effluent.
1 3
3.8 POUR FLUSH LATRINES
water does not need to be of high quality. There may be one or two pits
which may be below the latrine or off-set.
Another way of creating a barrier with water is to install a water seal, or
These water-seal toilets are effective in preventing access by insects and
trap, in the disposal chute beneath the squat plate or latrine seat. These
in eliminating odours. They are, however, likely to block, especially if solid
traps can have various configurations but require a bend in the pipework
materials are used for anal cleaning. They can be installed inside a house if
in which water is permanently located. Faeces are cleared after each use
the pit is off-set. Care should be taken with the discharge pipes and pits
by flushing with a sufficient quantity of water to wash the solids through
should be located at a distance from the house not less than the depth of
into the pit or vault. A minimum of one litre is needed for each use and the
the pit to avoid any effect on the house foundations.
The volume of effluent produced from these latrines can pollute shallow
ground water resources, and on a small island may ultimately affect near-
shore, particularly lagoonal waters.
Pour Flush
Latrine
A latrine may be fitted
3.
3 9
.
9 S
E
S P
E T
P I
T C
I
C T
A
T N
A K
N S
K
with a trap providing a
water seal, which is cleared
If a higher amount of wastewater is being produced through flushing,
of faeces by pouring in
washing, cooking etc., a septic tank can be used to treat the waste water
sufficient quantities of
from a wet latrine to improve the quality of effluent which is discharged
water to wash the solids
into the environment
into the pit and replenish
the water seal. A water
Septic tanks are essentially an enclosed tank constructed of concrete,
seal prevents flies,
polyethylene or fibreglass, in which suspended solids settle and scum floats
mosquitoes and odours
Source: WHO (1991)
on the top, as shown in the diagram at the top of the page across. The
reaching the latrine from
waste water is partially treated in the 1-3 days it remains in the tank. 60-
the pit. The pit may be offset from the latrine by providing a
70% of the suspended solids (SS) and about 30% of the BOD are removed.
short length of pipe or covered channel from the pan to the
A continuous piped water supply is necessary to flush the solids through
pit. The pan of an offset pour-flush latrine is supported by
the system. Effluent from the septic tanks is disposed of to the surrounding
the ground and the latrine may be set within or attached to
ground via soakpits or tile drains laid out in trenches, or can be tied into a
a house. Advantages are low cost, control of flies and
piped sewer system.
mosquitoes, absence of smell, contents of pit not
visible, gives the users the convenience of a WC and can be upgraded by
The disposal to ground depends on available land area, the permeabil-
connection to sewer when sewerage system becomes available. Also, for the
ity of the ground and the depth to water table. In Tonga soakpits are used,
offset type of pour-flush latrines, the pan is supported by the ground and
2 metres in diameter and 2 metres deep, where the water table is below 4
the latrine can be inside the house. The disadvantages are that a reliable
metres below ground level. Septic tanks there are designed on a one day
(even if limited) water supply must be available and that it is unsuitable
hydraulic retention time with an allowance of 55 litres of sludge per capita
where solid anal cleaning material is used.
1 4
per year, (l/c/y). Desludging is assumed to be needed every seven years
with wastewater throughput of 80-100 l/c/day.
Desludging, that is the removal of the solids when they occupy half to
two thirds of the total depth between the liquid and the bottom of the
tank, is required on a regular basis. Depending on the size of the tanks and
the number of users this may be needed every 2 to 7 years.
Septic tanks are more expensive than the simpler forms of pit latrines
but can be used on small islands in low density urban areas, where in-
comes may be high enough to allow a higher water consumption and to
purchase and operate these systems and where environmental and ground
water pollution problems are not likely to occur.
Septic Tank
Main advantage is that it gives the users the convenience of a WC,
Source: Gunn, 1989
and the disadvantages are its high cost, the dependence on a relaible
and ample piped water required,
that it is only suitable for low-
density housing, that regular
desludging isrequired - sludge
needing careful handling, and
that permeable soil is required.
Source: Intermediate Technology, 1991
1 5
3.10 SEWERED SYSTEMS
In urban areas where it is possible to impose some form of charge for
waste water disposal a piped sewer system , taking the effluent to a treat-
ment plant or to a natural water body such as the sea or a river can be used.
They are expensive to construct and need efficient operation and main-
tenance to ensure blockages do not occur and that the outfall are kept in
good working condition.
Sewers of smaller diameter than usual (small-bore sewerage), sewers
built nearer to the surface than usual, and sewers with flatter gradient than
usual have been tried. Many of these systems require a chamber at each
house to retain solids, which have to be removed and disposed of from
time to time. Some of these systems have been found to be suitable for
providing sanitation simultaneously for a large number of high-density dwell-
Sewered System
ings (Mora, 199x)????
Discharge from WCs and other liquid
In some high density areas of Pacific Island countries, such as Tarawa in
wastes flow along a system of sewers to
Kiribati and Majuro in the Marshall Islands, there are sewer systems flushed
treatment works or directly into the sea or a river..
by a saltwater source. These require careful attention to operation and
The advantage is that the user has no concern with what happens after
maintenance because of the corrosive nature of sea water, and can be
the WC is flushed. Disadvantages are high construction costs, that it
expensive because of the need for non-corrosive pumps, pipes and fittings.
requires an efficient infrastructure is required for construction,
operation and maintenance, and that an ample and reliable piped
water supply is required for operation. A minimum of 70 litres per
person per day is recommended if discharge is to a water-course.
Adequate treatment is also required for excreta to avoid pollution.
1 6
AVAILABLE TECHNOLOGIES
CHOICE
RELATIVE COST
TECHNOLOGY
RISKS
RESOURCE
PATHOGEN
PATHOGEN
CONSTRAINTS
ADVANTAGES
RECLAMATION
CONTAINMENT
REMOVAL
beach/bush
zero
zero
direct F/O
no/yes
no
?
low population
easy
transmission
good tidal flush (beach)
designated defecation site (bush)
night soil
low
very low
F/O transmission
yes
yes
no
requires designated safe disposal
easy, private
at spills
good access to houses
social odium
vectors/vermin
at disposal site
pit latrines
low-moderate
low
vector breeding
yes/maybe
yes
yes
requires land
private
general
low-moderate
low
pollution potential
yes/maybe
yes
yes
deep soil/water table
low O and M
contains pathogens
wet pit
low-moderate
low
groundwater pollution
yes/maybe
yes
yes
requires permeable soils
slow to fill
dry pit
low-moderate
low
yes/maybe
yes
yes
ventilated
low-moderate
low
yes/maybe
yes
yes
requires exposed site for sunlight and wind
odourless
traps vectors
septic tanks
general-tank
moderate-high
medium
vector breeding
yes/maybe
yes
yes
requires water supply
proven technology
poor construction
requires desludging facility
absorption
moderate
low
groundwater pollution
yes/maybe
yes
yes
requires depth of soil/water table
simple
ET
moderate
low
plants may not tolerate
yes/maybe
yes
yes
requires land area
simple
wetlands
moderate-high
medium
overflow, vector breeding
yes/maybe
yes
yes
requires land area
minimal discharge
filters/aeration
high
high
breakdown problems
yes/maybe
yes
yes
expensive
high quality effluent
mix'n match
water-borne
small sewers
high
medium
pipe-damage pollution
maybe
yes
yes
requires pipeline routes
removes wastes
households may not connect
requires safe disposal areas
municipal sewers
very high
high
breakdowns
maybe
yes
yes
requires pipeline routes and pumps
clean, modern
requires treatment/disposal areas
high O and M costs
composting toilet
moderate
medium
very few
yes
yes
yes
requires dry organics
very clean
requires high set structure
1 7
4. MAKING THE CHOICE
After the important stage of communication and consultation, and as-
Ar
A e
r
e l
o
l c
o a
c l
a
l m
a
m t
a e
t r
e i
r a
i l
a s
l
s a
n
a d
n
d l
a
l b
a o
b u
o r
u
r a
v
a a
v i
a l
i a
l b
a l
b e
l ?
e
suming that all the facts and information on needs, health and technology
have been made available, comes the time to choose a design.
The cost of constructing a new sanitation facility can be greatly decreased
if local materials are used and if local labour can be employed to build the
The following criteria must all be considered in making the selection. It
latrines. Organisation of the work can assist the speed and efficiency with
should be noted that the initial choice is one for a trial installation to dem-
which the improvements can be made. Personnel for technical supervision,
onstrate the suitability and effectiveness of a particular design. Changes
if available, will also ensure good construction and later operation and
can be made if problems occur in this initial trial period, including small
maintenance of the structures.
and large design modifications.
Are there any social, religious or cultural constraints to the choice?
Some existing conditions or constraints may be compatible with good
Wh
W a
h t
a
t a
r
a e
r
e t
h
t e
h
e p
r
p i
r o
i r
o i
r t
i i
t e
i s
e ?
s
health and environmental needs. Others may have to be discussed as being
detrimental to the well being of the particular society. The choice, how-
Often the basic need is for improved sanitary conditions for health rea-
ever, must always be with the recipients of the sanitation.
sons. The chosen technology must be able to provide the improvement in
sanitation required. For this a programme of health and hygiene education
associated with the use of the sanitation facility is essential. The impor-
Ca
C n
a
n t
h
t e
h
e c
o
c m
o m
m u
m n
u i
n t
i y
t
y a
f
a f
f o
f r
o d
r
d t
h
t e
h
e c
h
c o
h s
o e
s n
e
n d
e
d s
e i
s g
i n
g ?
n
tance of handwashing, for example, is vital if transmission of enteric patho-
gens is to be totally eliminated.
To be affordable does not necessarily mean ready cash is needed. Credit
Associated with the provision of a barrier from direct or indirect contact
facilities may be available to the users which they can arrange themselves.
with excreta is the need to protect any water sources which can be an
Wherever possible private sector local builders should be used with local
additional health hazard if waste water from the latrines reaches these
assistance.
sources.
There should always be some financial input from the recipients to en-
sure there is a feeling of ownership. As a general rule, the users should
always pay fully for the operation and maintenance of the system. Wher-
Ho
H w
o
w i
m
i p
m o
p r
o t
r a
t n
a t
n
t i
s
i
s t
h
t e
h
e e
n
e v
n i
v r
i o
r n
o m
n e
m n
e t
n ?
t
ever possible latrines should belong to individual households. Community
toilets seldom are maintained adequately.
If effluent from latrines is produced in sufficient quantity the general
environment can deteriorate with the addition of nutrients and pathogens
to coastal, ground and inland water bodies. Economic activities such as
Wi
W l
i l
l
l t
h
t e
h
e u
s
u e
s r
e s
r
s l
i
l k
i e
k
e t
h
t e
h
e t
o
t i
o l
i e
l t
e s
t ?
s
fishing and tourism can be adversely affected by degradation of the envi-
ronment.
If the design is to be widely accepted it must be liked. This means that it
should be attractive, odourless, comfortable, easy to use, simple to clean,
suitable for adults and children, and not offend any social or cultural norms.
1 8
Even with all the above information and considerations it will not be
the water table is more than 3-4 metres below ground level, and
possible to provide or afford the ideal sanitation. Some compromise is
the soil is relatively permeable
always necessary. A suggested approach might be community based risk
management. For this the community sets objectives for their needs/wants
consider using one of the wet latrine technologies: 3.7 to 3.10.
in terms of improved sanitation facilities. Depending on finances, limits
may have to be set on the health and environment needs required at the
stage of development. Technology is then chosen to match the require-
If any of the above conditions are not met consider using one of the dry
ments. It should be noted that the facilities can be further upgraded at a
latrine technologies: 3.2 to 3.5.
later stage, particularly if appropriate designs are chosen to allow this.
Where dry latrine methods are chosen:
I
f
: it is not possible to dig a pit;
We
W t
e
t o
r
o
r D
r
D y
r ?
y
the water table is shallow, (<3metres); and
I
f
: water for flushing is available all the year round,
people do not object strongly to handling human excrement as a soil
conditioner consider usind a composting toilet: 3.6.
water is used for anal cleaning,
1 9
5. TRIALS AND DEVELOPMENT
To try out a particular type of sanitation takes time. There are no short
couraged and enabled to acquire satisfactory and adequate sanitation within
cuts in a pilot project. Planners of improved sanitation must conduct the
a certain period of time.
economic and social research outlined in previous sections of this booklet,
Finally comes a mobilisation or expansion phase when most of the facili-
build and demonstrate the chosen units, monitor and evaluate reactions
ties are constructed. This should be accompanied by monitoring and evalu-
before a truly appropriate and acceptable latrine can be found. In Lesotho
ation to determine how effective the improvements are.
in Africa, for example, a sanitation project stretched from the 1970s to the
1990s. The actual time scale will depend on the size of the population to
be served, the receptivity of the users and the financial resources available.
Such projects will cover years. Sanitation development cannot be done in
a hurry.
After the initial feasibility studies, surveys and community consultation,
comes the demonstration or experimental phase. This is a practical test of
the feasibility of the recommended or chosen options. This acts as a kind of
shop window to stimulate demand. It also acts to prove that the basic tech-
nology is feasible before widespread implementation of the design.
This is followed by a period of consolidation to organise the institutional
aspects of the project. In this period householders and institutions are en-
Source: WHO, (1991)
2 0
6. FINAL THOUGHTS
Co
C n
o t
n r
t o
r l
o
l M
e
M a
e s
a u
s r
u e
r s
e
it must be affordable to the majority of the community and it must be
adequate to bring about the improvements to health and environment which
There is much that can be done to avoid the need for expensive forms
have been identified as needed.
of sanitation on small islands. For example planning regulations can be in-
troduced to limit population densities becoming too high, generally requir-
But it does not stop there. Latrine construction is only the beginning of
ing sewered systems. Well-head protection zones can be introduced to
the real sanitation programme. Continuing health and hygiene education
maintain a minimum separation distance between drinking water wells and
are necessary if the recipients are to realise the benefits of their invest-
sanitation facilities. Monitoring procedures can be introduced to ensure
ment. Technical assistance is needed to ensure the new systems function
water supplies are not being affected by existing sanitation facilities.
properly. A great deal of time may be needed to try out and encourage the
use of new means of sanitation. It may take several years to stimulate de-
If there is a health or environmental problem in a small island situation it
mand in a community. There will follow a consolidation phase in which the
is necessary first to ask what the options are and how each will improve the
institutional arrangements will be worked out, that is who will organise
existing situation. A dialogue must form the first part of the investigation of
repayments, who will be responsible for maintenance, etc. Ultimately there
sanitation development. Wants and needs must be clearly identified both
will be an expansion phase when all households may see the need to ob-
by those receiving the sanitation and those able to provide the guidance
tain equal status with their neighbours in terms of available sanitation. A
and assistance.
mix of assistance, motivation and legislation may be necessary to produce
After this initial discussion, in which all information must be made avail-
the desired results of improved health and environment through sanita-
able, a choice has to be made. This may not always be the ideal sanitation
tion.
facility, but it still must be acceptable to those asking for the improvements,
2 1
7. SOME SOURCES FOR FURTHER READING
Bencke, B. 1996, The Advantages and Disadvantages of Septic Tanks in Proceedings of a
workshop on "Appropriate and Affordable Sanitation for Small Islands" Tarawa,
Lewis, W. J. et al 1986, The Risk of Groundwater Pollution by On-Site Sanitation in
Kiribati, 6-8 Aug 1996, SOPAC.
Developing Countries. A Literature review. IRCWD, Switzerland Report 01/82.
Blackett, I.C. 1994, Low-Cost Urban Sanitation in Lesotho. UNDP-World Bank Water and
Piekema, P.G. 1995, Review and development of Tokelau water supply, sanitation and
Sanitation DP No 10.
solid waste programme. WHO Mission
Report.
Canter, L. W. et al 1988, Ground Water Quality Protection. Lewis Publishers, Michigan,
Rapaport, D. 1996, The CCD Toilet. An Aerobic Double Vault Composting Toilet for
562 p.
Tropical Environment That Achieves Zero Discharge Sanitation with Low Maintenance
Requirements.
Chapman, P. D. 1995, Compost Toilets. The Much Maligned Faecal Waste Treatment
Option. Water and Wastes in N.Z. July 1995, p 30-31,44.
Rapaport, D. (ed) 1996, Sewage Pollution in the Pacific and How to Prevent it.
Greenpeace Pacific Ltd., Suva, Fiji.
Crennan, L. 1996, Composting Toilet Trial on Kiritimati, Kiribati. Case Study 4 in "Tech-
nologies for Augmenting Freshwater Resources in Small Island Developing States",
Santo, S. 1995, Knowledge, Attitudes and Practices Research on Diarrhoeal Diseases for
SOPAC/UNEP Joint Contribution 112.
the Kiribati Child Survival Project. Australian Centre for Tropical Health and Nutrition,
University of Queensland. F.S.P. Tarawa.
Depledge, D. 1996, Design Examples of Waterless Composting Toilets. SOPAC Miscel-
laneous Report 249.
Winblad, U. and Kilama, W. 1985, Sanitation Without Water Macmillan Education.
Swedish Int. Dev. Authority.
Dharmabalan, P. 1988, Small Waste Disposal Systems. Unitech, Lae, PNG, Dept of Civil
Engineering.
Winter, S.J. 1988, Construction Manual for a Water-sealed Toilet UNDP, Office for Project
Services, Integrated Atoll Development Project.
Dillon, P. 1996, Groundwater Pollution by Sanitation on Tropical Islands. A UNESCO/IHP
Study. CSIRO Centre for Groundwater Studies No 6x. July 1996.
Winter, S.J. 1996, Sanitary Facilities in the Remote Areas of Micronesia in proceedings of
SOPAC Workshop on Appropriate and Affordable Sanitation, Tarawa, Kiribati, 6- 8
Franceys, R. et al 1992, A guide to the development of on-site sanitation. WHO, Geneva,
August 1996.
1992.
World Bank 1986, Information and Training for Low-Cost Water Supply and Sanitation
Furness, L. 1996, Assessment of Spacing Between Sanitation Facilities and Wells on Lifuka
5.3 Sanitation Technology Selection IBRD/World Bank, Washington, D.C.
Island, Kingdom of Tonga.Groundwater Pollution Study. Report on the UNESCO IHP
Project 3.
N.
N B
. .
B
. M
o
M s
o t
s
t o
f
o
f t
h
t e
h s
e e
s
e p
u
p b
u l
b i
l c
i a
c t
a i
t o
i n
o s
n
s a
r
a e
r
e a
v
a a
v i
a l
i a
l b
a l
b e
l
e a
t
a
t t
h
t e
h
e S
O
S P
O A
P C
A
C L
i
L b
i r
b a
r r
a y
r
y i
n
i
n S
u
S v
u a
v .
a
Gunn, I. 1989, On-Site Wastewater Disposal from Households and Institutions. ARWB
Tech Publication No 58.
Fu
F r
u t
r h
t e
h r
e
r l
i
l t
i e
t r
e a
r t
a u
t r
u e
r
e c
a
c n
a
n b
e
b
e o
b
o t
b a
t i
a n
i e
n d
e
d f
r
f o
r m
o :
m
Isely, R. B. et al 1986, Framework and Guidelines for CARE Water and Sanitation
SO
S P
O A
P C
A
C S
e
S c
e r
c e
r t
e a
t r
a i
r a
i t
a ,
t
, P
r
P i
r v
i a
v t
a e
t
e M
a
M i
a l
i
l B
a
B g
a ,
g
, G
P
G O
P ,
O
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u
S v
u a
v
Projects, WASH Tech Report No 40.
an
a d
n
d t
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t e
h
Kolam, J. 1996, Sanitation Issues in Papua New Guinea in Proceedings of SOPAC
Workshop on "Appropriate and Affordable Sanitation for Small Islands", Tarawa,
Wo
W r
o l
r d
l
d H
e
H a
e l
a t
l h
t
h O
r
O g
r a
g n
a i
n s
i a
s t
a i
t o
i n
o
Kiribati, 6-8 Aug 1996.
2 2
8. TECHNICAL TERMS
ae
a r
e o
r b
o i
b c
i
pa
p t
a h
t o
h g
o e
g n
e
living or taking place in the presence of air or free oxygen
organism that causes disease
an
a a
n e
a r
e o
r b
o i
b c
i
scum
living or taking place in the absence of air or free oxygen
layer of suspended solids less dense than water and floating on top of liq-
uid waste
bi
b o
i c
o h
c e
h m
e i
m c
i a
c l
a
l o
x
o y
x g
y e
g n
e
n d
e
d m
e a
m n
a d
n
(BOD), the mass of oxygen consumed by organic matter during aerobic
so
s a
o k
a p
k i
p t
i
decomposition
hole dug in the ground serving to disperse liquid waste
co
c m
o p
m o
p s
o t
s i
t n
i g
n
sq
s u
q a
u t
a
t h
o
h l
o e
l
the controlled decomposition of organic solid waste in moist conditions to
hole in the floor of a latrine through which excreta falls directly to a pit
produce a humus
below
de
d s
e l
s u
l d
u g
d i
g n
i g
n
su
s p
u e
p r
e s
r t
s r
t u
r c
u t
c u
t r
u e
r
removal of settled solids from pits, vaults and tanks
screen or building of a latrine above floor level for privacy of users.
ef
e f
f l
f u
l e
u n
e t
n
ve
v n
e t
n
t p
i
p p
i e
p
liquid flowing out of a pit, tank or sewage works
pipe provided to facilitate the escape of gases from a latrine or tank
he
h l
e m
l i
m n
i t
n h
t
wa
w t
a e
t r
e
r c
l
c o
l s
o e
s t
e
a worm, which may be parasitic or free living
W C pan from which excreta is flushed by water into a drain
humus
decomposed organic matter
2 3
NOTES
2 4