E1288
Environmental Management Plan
v10
PROJECT 7 SEWAGE AND SEPTAGE TREATMENT PLANT
Public Disclosure Authorized
PROJECT DESCRIPTION
MWSS received Technical Assistance (TA) financing from the World Bank
in 2005 to partially update their Water Supply Master Plan and to prepare a
comprehensive Master Plan for Sewerage and Sanitation for its service area to the
year 2025. The 2005 Master Plan proposed a decentralized small-bore sewerage
approach and 16 new regional combined STP-SpTP's, utilizing anaerobic biological
treatment.
Combination sewage-septage treatment plants are common in the US (25%
of the US population have septic tank) and Australia, with septage to sewage
Public Disclosure Authorized
portions usually less than 5%. One combined plant in Greece treats up to 40%
septage with sewage. The advantages of combined sewage-septage treatment
plants include I) Possible revenue for the treatment plant from independent haulers,
ii) Use of excess treatment plant capacity maximum utilization of vacuum trucks, iii)
Availability of a legitimate septage disposal site for independent haulers, and iv)
Regional centralization of waste treatment facilities to name a few.
The MWSI Project 7 Communal Septic Tank is conceived for a proposed
protoype Sewage-Septage Treatment Plant (STP-SpTP) in 11 Road A, St Anthony
Village, Quezon City which drains 45.6 ha. Of sewerage reticulation. It was
selected due to a number of advantages, including a) site is in MWSI's area b)
Public Disclosure Authorized
Project 7 currently has a poorly operating treatment system the pollutes Culiat
Creek c) The site area consists of about 1300 sq.m. d) There are no informal
settlers on the site e) The site is government owned f) there are significant numbers
of septic tanks in adjacent areas to draw septage g) access road is reasonable and
trucks regularly come and go from the site h) the site is close to MWSI offices in
Balara for monitoring, and I) sewage flow is something less than about 2 MLD.
The process design consist of an anaerobic (UASB) aerobic (SBR)
biological treatment plant. Other process components would include possible reuse
of the imhoff tanks for balancing, new sewage inlet works, a septage acceptance
area, biosolids dewatering building and equipment, new chlorination disinfection
system and contact tank, and odor control. The process will used 10% septage
(240 m3/d), anaerobic-aerobic biotreatment. Theoretically, effluent from the
Public Disclosure Authorized
proposed STP/SpTP not only meets the required standard specified in DENR AO
35, but should surpass the prescribed effluent water quality at all times. BOD5,
COD and TSS concentrations are expected to decrease to 22 mg/l, 72 mg/l and 30
mg/l, respectively, after treatment. Applying mass balance analysis for all systems
Maynilad Water Services, Inc. Page 1
Environmental Management Plan
shows that processing 2,400cmd of sewage + 240cmd of septage will result to
about 2,393cmd of treated wastewater, 103cmd biosolids, and 144cmd screened
and degrited wastes. Biomass produced daily for possible reuse as soil conditioner
contains about 99kg of BOD5 and 660kg TSS. Figure 1-1 presents the mass
balance flow diagram for the proposed prototype STP/SpTP.
In SpTP, the estimated overall removal efficiency in terms of BOD, COD and
TSS are 93%, 94% and 97%, respectively. However, treatment efficiency in STP is
lower with approximately 80% for BOD, 80% for COD, and 85% for TSS. Dilution of
primary effluent with screened sewage and absence of pre-aeration in the system
results to further decrease in concentration of pollution loads causing lesser amount
of micro-organism in the reactor. Table 1-1 summarizes the theoretical
performance of the STP-SpTP.
Project 7 would help MWSI better utilize their current fleet of 32 septic tank
pump out trucks ( includes 7 Mobile Dewatering Units). MWSI estimated that the
current average for truck trips to Dagat-Dagatan STP-SpTP is about 1.2 or 257 m3
septage/day. At that frequency, the number of 5 m3 septic tanks desludged
annually (300days/year) is about 15,700.
Project 7 could potentially increase the number of trips per day per truck to a
treatment facility to 1.5 (estimate by MWSI). At that frequency, the number of 5 m3
septic tanks desludged annually (300 days/year) would be about 19,500 (24%
increase), with the septage delivered being about 321m3/day (25% increase). A
more detailed traffic/septic tank pumpout study would be required to fully verify the
effect of adding Project 7.
Another point worthy of note is that West Quezon City (QC) has a high
sanitation target for MWSI by the year 2021. A STP-SpTP in West Quezon City
would be well placed to help deliver on this target.
The Manila Third Sewerage Project (MTSP) Global Environmental Facility
(GEF) proposed prototype STP-SpTP will likely be the first of many similar
decentralized sewerage and treatment plants if the 2005 Master Plan is
implemented. Sixteen regional STP-SpTP's were proposed to be operating by 2025
to address the most serious of the pollution hot spots in the MWSS service area.
The fact that the proposed Project 7 site, one of about 1,300m2 , can support both
2.4 MLD of sewage, plus up to 15% septage (or 360 m3/d) also contributes to the
replication concept around land-scarce Metro Manila
Maynilad Water Services, Inc. Page 2
Environmental Management Plan
Figure 1.1 Mass Balance Flow Diagram
Ra
R w Se
w S wage
g
Q, c
Q, md
m
24
2 0
4 0
0
BOD
BO , mg
, m /l
g
10
1 6
0
5
Screeni
n ng
n
COD,
CO m
D, g
m /
g l/
24
2 6
4
Q, c
Q, md
m
22
2 8
2 0
8
TSS
TS ,
S m
, g
m /
g l/
88
8
BOD
BO , mg
, m /l
g
95
BOD
BO , kg
, k /
g d
/
25
2 4
5
54
5
TSS
TS ,
S k
, g
k /
g d
/
21
2 1
1
Od
O our
COD,
CO m
D, g
m /
g l/
20
2 9
our
0
Cont
Con rol
TSS
TS ,
S m
, g
m /
g l/
75
ol
o
7
BAR
BOD
BO , kg
, k /
g d
21
2 8
1
5
SCREEN
TSS
TS ,
S k
, g
k /
g d
17
1 1
SCREEN
SCREE
7
Raw Se
S pt
p age
g
Odour
O
Q, c
Q, md
m
24
2 0
4
Contr
Cont ol
Ef
E fflfuent DA
D O
A 3
O 5
3
BOD
BO , mg
, m /l
g
2,7
2 5
,7 2
5
5
Q,
Q cmd
m
2393.0
393. 6
-
CO
C D
O ,
D m
, g
m /l
g
20,2
20 63
,2
BOD
BO , mg
, m /l
g
22
2
50
5
5
TSS, mg/l
35,650
2658.96
2658.9
CO
C D
O ,
D mg/
m l
g/
72
100
ST
Equalization
109
BO E
SS,
SE
SD , kg/d
660
5
P
mg
Equalization
10
, kg/ T
/l
d
P
TSS, mg/l
30
75
AG
A E
G
TSS, mg/l
30
75
A35,650
BOD
660
5
Q, cmd
Q, cm
361
36
TS
T S
S ,
S k
, g
k /d
g
8,55
8, 6
55
,
mg/l
mg/
BOD
BO , kg
k /d
52
5
-
201
20
5
BOD5
BOD
291
Od
O our
TSS, kg/d
72
-
COD, mg/l
291
Od
TSS, kg/d
72
-
COD, mg/l
TSS, mg/l
TSS, mg/d
535
53
Cont
Con rolo
Odo
Od ur
ZA OkNg/
T, I,kg/d
r
ALIZATION
EQUALIZATIO
BOD5
BOD
D
Control
TSS, kg/d
D
TSS, kg/
M ass Balance
Value
ISC
AR
TANK
N
M ass Balance
Value
I
Control
S
TA
C
BAR
H
Influent,cmd
2640.00
AR
EEN
Influent,cmd
2640.00
ARG
SCREE
E
SBR
SB
2658.96
2658.922
Effluent,cmd
2393.06
E
2
Effluent,cmd
2393.06
E TO
Q, cmd
Biosolid,cmd
102.93
C
SBR
Q, cm
Biosolid,cmd
102.93
C
SBR
UL
72
L
7
, mg/l
Screen&Grit,cmd
144.00
I
Screen&Grit,cmd
144.00
AT
,
mg/
BOD5
30
Biomass
HLORINE
BOD5
3
C
Biomass
RE
COD, mg/l
BOD,kg/d
99.14
E
CHLORINE
EK
CONTACT
ACT
COD, mg/
BOD,kg/d
99.14
E
CHLORINE
K
CONTACT
58
5
TS
T S
S ,
S k
, g/
k d
660.
6
4
60. 9
4
TANK
TSS, mg/l
TSS, mg/
80
8
,
,kg/d
kg/
R
Cl2
BOD5
2
BOD
(
R
(
E
S
U
O
S
TSS, kg/d
TSS, kg/
IL
S
L
E
CONDITION
Od
O our
NER)
GRIT
Cont
Con rol
)
o
)
BER
CHAMBE
Odo
Od ur
Odo
Od ur
Control
Contr
Cont ol
SBR
SB
D
Q,
Q cmd
m
541.37
E
E
BOD , mg/l
193
5
A S T E S L U D G E
BOD , mg/l
193
T
W A S T E S L U D G
5
T
W A S T E S L U D
I
CO
C D
O ,
D m
, g/
m l
1,277
Ce
C ntr
nt ifiuge
f
G
R
TS
T S
S ,
S m
, g/
m l
1,283
Q,
Q c
, md
m
158.
158 3
. 5
3
G
CENT
N RI
R FUGE
E
E
BOD
BO , kg
k /d
g
10
1 4
0
5
5
BOD
BO , kg
, k /d
g
15
1 3
5
D
SBR
E
R
BOD , kg/d
153
D
SB
G
5
TSS, kg/d
695
5
U
TSS, kg/d
695
TSS,
T
k
SS, g
k /
g d
/
1,
1 0
, 1
0 6
1
D
A
TSS, kg/d
1,016
D
L
Sc
S reening &
n
De
D griting
&
it
T
Od
O our
&
S
Odour
D
P
Q, c
Q, md
m
21
2 6
1
E
E
Cont
Con rolo
Cont
Con rol
N
BOD
BO , mg
, m /l
g
1,9
1 2
,9 6
2
S
5
E
E
ion
CO
C D
O ,
D m
, g/
m l
g/
14,18
14, 4
18
Eq
E u
q a
u lizatiton
E
Di
Dgegster
T
TS
T S
S ,
S m
, g/
m l
g/
21,39
21, 0
39
Q,
Q cmd
m
54
5 1
4 .
1 37
3
R
963
C
BOD
BO , kg
, k /d
g
41
4 6
1
5
Q,
Q cmd
m
16
1 26.2414
S
C
BO
B D
O , mg
m /
g l
963
BOD , kg/d
4
5
5
S
A
TSS,
T
k
SS, g
k /
g d
/
4,
4 6
, 2
6 0
2
CO
C D
O ,
D mg
m /
g l
6,
6 38
3 3
8
AERBO
OD
ERO B , kg/gd
1565
TSS, mg/l
8,556
5
OB
O IC
C
W
EQUALT
EQ
IS
UAL ZS,A
Z T
mg
A I/l
T ON
O 8,55
BO
B D
O , kg
k /
g d
52
5 1
2
DI
D GE
GTST
SS
S ,S Ek
STgR
1,042
TANK 5
/dR
1,042
NKTSTSS,S kgk/gd
4,
4 63
6 2
3
F
F I L
L T
T R
R A
A T
T E
Table 1.1 Theoretical Performance of Proposed STP-SpTP
Maynilad Water Services, Inc. Page 3
Environmental Management Plan
Septage Treatment Plant
Sew age Treatment Plant
Parameter
Unit
Raw
Equalization After SBR
Mixed
After SBR
DAO 35
Equalization
Septage
(Pre-aeration) Treatment
Sew age
Treatment
BOD
mg/l
2,752
963
193
109
109
22
50
5
COD
mg/l
20,263
6,383
1,277
361
361
72
100
TSS
mg/l
35,650
6,417
963
201
201
30
70
2.0
MAJOR IMPACTS AND MITIGATING MEASURES
Impacts have been identified during construction and operation as shown
below:
2.1 During Construction
a)
Increased noise level in the vicinity. The noise level will increase
temporarily during the construction due to piling activity. Noise level from
piling activity is estimated at 75-110 dBa measured at 5 to 40 m distance.
Close supervision of the construction will be undertaken to minimize
indiscriminate noise production from construction activities. In addition,
temporary wall barriers will be placed to reduce noise level. Nighttime pile
driving will not be allowed unless necessary.
b)
Increased air (dust) pollution. Air pollutants such as dust, Sox, Nox
and particulates can be prevented and minimized by regular
watering/sprinkling of roadway during dry and windy season.
c)
Open excavation may cause accidents. To prevent accidents
during construction, barricades and steel plates cover will be provided to
open excavations during non-working time.
d)
Volume of spoils or excavated materials. Excess excavated
materials must be immediately removed from the site and dumped in
designated disposal site in a manner that would not obstruct the flow of traffic
or jeopardize the safety of motorists.
2.2 During Operation
Maynilad Water Services, Inc. Page 4
Environmental Management Plan
a)
Increased noise level in the vicinity. During plant operation, noise
generated from the equipment is minimal since the equipment are housed in
concrete buildings. Concrete walls of building will serve as sound barriers.
b) Deterioration
of
surrounding air quality due to odor. Odor
generated during the transfer of septage from the hauling trucks to the
sludge holding tanks of the treatment plant will be mitigated by the odor
treatment facility installed in the treatment plant. The odor treatment facility
will be designed composing of air suction fans, activated carbon absorption
towers and forced ventilation systems. All equipment are also housed inside
the buildings with double walls and provided with ventilation. Air emission
quality within the vicinity will be monitored.
c)
Traffic congestion along the main and access roads. Road traffic
due to incoming and outgoing trucks will be mitigated with close observance
of traffic rules and regulations within the STP complex. Traffic rules, such as
prohibiting septage trucks from parking on major roads leading to the
treatment plant and delivery of septage during off-peak hours must be
observed. Traffic officers must be assigned to handle traffic on all access
roads in the vicinity of the treatment plant.
e)
Deterioration of public health. Public health of residents in the
vicinity might be affected by the change in the air quality. The chances of
adverse changes in air quality would be very slim, since mitigating measures
have been provided such as odor control and regular monitoring. In addition,
MWSI shall keep the plant site clean and orderly to prevent malodor and
flies. A regular health check will be conducted on nearby residents. A
medical station is provided within the complex to safeguard the health of the
residents and the workers as well.
f) Flooding during high monsoon rains or typhoon
The flooding problem due to its low elevation will be mitigated with the
provision of sufficient drainage system in the plant area.
3.
ENVIRONMENTAL ENHANCEMENT PROGRAM
Maynilad Water Services, Inc. Page 5
Environmental Management Plan
MWSI will implement the following environmental enhancement program in
order to ensure the protection of the receiving water and the atmosphere.
3.1 Supervision and Monitoring.
During construction, MWSI will ensure that the construction is carried out
according to the detailed design and Bid Documents/Contract Documents (BD/CD)
and contractors will follow the MWSI Safety Code (Chapter 5, see attachment).
Contractors will also post an All Risk Performance Bond.
3.2 Environmental Monitoring Activities
3.2.1 Air Quality and Noise Level Monitoring
MWSS will monitor the air pollutants level such as total
suspended particulates (TSP), sulfur dioxide (SO2), and nitrogen
oxides (NOx) and noise level once a month. Three (3) stations as
identified in Figure 3.2.1 located at 10 m, 30 m and 50 m are the
designated sampling site. When the level of air and noise fall above
the limits, immediate action will be undertaken by MWSI. Noise level
should not be allowed to exceed 65 decibel at 10 m distance from the
plant.
3.2.2 Water Quality Monitoring
A plant operation manual will be made by the winning
contractor that details the operation and maintenance of each facility
in the STP. In addition, MWSI shall also conduct routinary and
periodic water quality monitoring of septic tanks and at the STP. Table
II.1 shows the parameters to be tested, frequency of sampling and
location.
Receiving water shall also be monitored and sampling stations
shall be selected.
3.2.3 Odor
Monitoring
MWSI shall conduct weekly monitoring at 10 m, 30 m and 50
m from the source of odor as shown in Figure 3.2.3. The sample
collected shall be analyzed for the level of hydrogen sulfide and
ammonia compounds.
3.3
Public Education and Information Campaign
Maynilad Water Services, Inc. Page 6
Environmental Management Plan
During the construction and operation, a comprehensive public
information campaign shall be conducted within the vicinity of Dagat-Dagatan
area. Main objective is to educate and inform the people about the
significance of a septage treatment plant to the environment. Public
education will also tackle the roles of each individual in the protection of our
environment, the safeguard of health and the risk involved.
Figure 3.2.1 Noise Monitoring Stations in Project 7 proposed SSpT Plant
10 m
30 m
50 m
Figure 3.2.3 Odor Monitoring Stations in Project 7 proposed SSpT Plant
Maynilad Water Services, Inc. Page 7
Environmental Management Plan
30 m
10 m
50 m
Table I.
Monitoring Parameter and Frequency for Project 7 Sewage
and Septage Treatment Plant
Test Items
Influent
Effluent
Excess
Dewatered
Sludge
Sludge
Maynilad Water Services, Inc. Page 8
Environmental Management Plan
Routine Test
Temperature Daily Daily
Color/Odor Daily
Daily
Transparency Daily
Daily
pH Daily
Daily
Daily
DO Daily
SV
Periodical Test
COD Once/Week
Once/Week
BOD Once/Week
Once/Week
SS Once/Week
Once/Week
Once/Week
VSS Once/Week
Once/Week
TS Once/Week
Once/Week
Once/Week
Once/Week
TVS Once/Week
Once/Week
Once/Week
Once/Week
TDS
Once/Week
Once/Week
SM
Once/Week
Oil and Grease
Once/Week
Once/Week
Alkalinity Once/Month
K-N Once/Month
Once/Month
Once/Month
NH4-N Once/Month
NO4-N Once/Month
T-P Once/Month
Once/Month
Once/Month
PO4-P Once/Month
Detergent/Surfactant
Once/Week
Phenol Once/Month
Once/Month
Heavy Metals
Once/Month
Total/Fecal Coliforms Once/Week
Once/Week
Maynilad Water Services, Inc. Page 9
Environmental Management Plan
ENVIRONMENTAL MONITORING PLAN
Project Activities
Parameters
Location
Frequency Responsibilit
y
During Construction
Dust Construction
Site
Daily
MWSI
Noise Construction
Site
Daily
MWSI
Air Pollutants
Construction Site
Daily
MWSI
Spoil Materials
Construction Site
Daily
MWSI
Traffic Construction
Site
Daily
MWSI
Open
Construction Site
Daily
MWSI
Excavation
Erosion/Siltation Construction Site
Daily
MWSI
Operational Phase
Dust Treatment
Plant
Monthly
MWSI
Noise Treatment
Plant
Monthly MWSI
Air Pollution
Treatment Plant
Monthly MWSI
Odor Treatment
Plant
Daily MWSI
Wastewater
Treatment Plant
Weekly MWSI
Effluent Quality
Health and
Treatment Plant
Daily MWSI
Sanitation
Maynilad Water Services, Inc. Page 10
Environmental Management Plan
Public information campaign shall be in the form of organized
lectures, distribution of materials and site visits. In this way, the public will be
have an in-depth understanding of the treatment plant.
4. CONTINGENCY
PLAN
Contingency plan covers the different measures to be undertaken by
MWSI in case of the following incidents:
4.1
Accidental Septage Spill
Vacuum truck containing 0.5% hypochlorite solution shall be used to
flush septage to the drainage system. The area shall also be inspected for
any occurrence of septage related diseases for a period of one month. The
disinfectant, 0.5% hypochlorite solution, shall be prepared at the SSTP site
using powder chemical mixed in the cleaned vacuum cars.
4.2
Foul Odor Emission at the STP
MWSI shall immediately investigate. The sewage and septage
treatment operation shall also be stopped until the source of odor has been
identified and controlled.
4.3
Occurrence of Septage Related Epidemic in the Vicinity
The STP-SpTP operations shall be immediately stopped when related
health epidemics are reported. MWSI shall then conduct a complete
examination of the receiving water, as well as, the adjacent deepwells for
any contamination. Medical doctors and health workers shall be brought to
the site to investigate the occurrence of disease. It must also be reported to
the Department of Health.
In case of deterioration of effluent water quality discharged to
waterways, MWSI shall conduct a complete assessment of the viability and
functionability of all the unit processes or equipment immediately. Any
damaged parts shall be repaired or replaced immediately.
Maynilad Water Services, Inc. Page 11
Environmental Management Plan
5. ENVIRONMENTAL MANAGEMENT PLAN
Impact
Mitigation/Enhancement Institutional
Schedule
Description
Commitment
During Construction
1. Increased
Close supervision of the
MWSI
During
noise level
construction will be
construction
undertaken to minimized
indiscriminate noise
production from
construction activities
Temporary wall barriers will
be placed to reduce noise
MWSI
During
level
construction
Nightime pile driving will not
be allowed unless
MWSI
During
necessary
construction
2. Increased air
Air pollutants such as dust, MWS During
(dust) pollution
TSP,NOx, Sox can be
construction
prevented and minimized
by regular
watering/sprinkling of
roadway during dry and
windy season
3. Open
To prevent accidents
MWS During
excavation may
during construction,
construction
cause accidents
barricades and steel plates
cover will be provided to
open excavations during
non-working time/hours
4. Excess
Excess excavated
MWSI During
spoils/excavated
materials must be
construction
materials
immediately removed from
the site and dumped in
designated disposal site in
a manner that would not
obstruct the flow of traffic or
jeopardize the safety of
motorists
Maynilad Water Services, Inc. Page 12
Environmental Management Plan
Impact
Mitigation/Enhancement Institutional
Schedule
Description
Commitment
During Operation Phase
1. Air and Noise
MWSI will monitor the air
MWSI Once/Month
Pollution
pollutants level such as
TSP, Sox, NOx, and noise
level once a week. Three
designated stations will be
identified, 10, 30 and 50
meters
2. Increased
Noise generated from the
MWSI During
operation
noise level in the
plant equipment is minimal
vicinity
since the equipment are
housed in concrete
buildings
Concrete wall of building
will serve as sound barriers
3. Generation of
Odor treatment facility will
MWSI
During operation
odor
be installed in the treatment
plant to mitigate odor
generated during transfer
of septage from the hauling
trucks to the sludge holding
tanks
All equipments are housed MWSI
During operation
inside the building with
double walls and provided
with ventilation
Air emission quality within
MWSI
During operation
the vicinity will be
monitored
4. Deterioration
Effluent wastewater from
MWSI During
operation
of water quality
the treatment plant will be
monitoreddaily and should
meet the effluent standards
set by the DENR
5. Deterioration
MWSI shall keep the plant
MWSI
During operation
of public health
site clean and orderly to
prevent malodor and flies
Regular health check will
MWSI
During operation
Maynilad Water Services, Inc. Page 13
Environmental Management Plan
be conducted on nearby
residents. A medical
station will be provided
within the complex to
safeguard the health of the
residents and workers as
well
6. Flooding
The flooding problem due
MWSI During
operation
during high rains
to its low elevation will be
or typhoon
mitigated with the provision
of sufficient drainage
system in the plant area
Maynilad Water Services, Inc. Page 14
Document Outline