WEPA | SEAWE11 | 2014 | Thailand

Wastewater Managementin Bangkok
Suwanna Kitpati Boontanon
Assistant Professor
Faculty of Engineering, Mahidol University
November 28, 2014

Types of Centralized Wastewater Treatment
system in Thailand

Background

Wetland (2%)
Activated Sludge(36%)

Aerated Lagoon(16%)

Rotating Biologicalcontactor (1%)

Stabilization Pond
(45%)

Source: Saktaywin, W., 2013. WEPA workshop, Cambodia
Wastewater Management in Bangkok

Suwanna. K. Boontanon | Mahidol Univ. |Background Thailand : 14 million m3/d of wastewater generated
3 million m3/d of treatment capacity
21 %of people access to sewerage system

 Bangkok : 2.6 million m3/d of wastewater generated
1 million m3/d of treatment capacity
40 %Wastewater Management in Bangkok

of people access to sewerage system

Suwanna. K. Boontanon | Mahidol Univ. |3

Background

70 % of collected night soil is
disposed to environment

Sewer service area
21 %
On‐
site

No sewer service area

79 %
On‐
site

Wastewater Management in Bangkok

Wastewater
treatment
facility
Centralized& Cluster
WWTPs

Nightsoil
treat‐
ment
facility

70 %Landfills, agricultural field, waterways

30 %Suwanna. K. Boontanon | Mahidol Univ. |4

Coverage of Wastewater Treatment Plants
in BangkokBackground
1)
2)
3)
4)

Si Phraya Wastewater Treatment Plant
Rattanakosin Wastewater Treatment
plant
Din daeng Wastewater Treatment Plant
Chongnonsi Wastewater Treatment
Plant

5)
6)
7)
8)

Nong Khaem Wastewater Treatment
Plant
Thungkru Wastewater Treatment Plant
Chatujack Wastewater Treatment Plant
Bang Sue Environmental Conservationand Learning Center•Thasai•Thung Songhong I•Thung Songhong II•Bangbua•Raminthra•Huamark•Klong Chan

•Huay Khang

87321•Bonkai

54•Rom Klao

6•Klongtoey

Inner city
•Bangna

Urban fringe
SuburbanCentralized WWTP
Cluster WWTP

Wastewater Management in Bangkok

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Background

On-Site Water Quality: Influent and Effluent

Source: Dulyakasem, S., et. al., 2013. Determinations of Blackwater characteristics and sludge accumulation rates in
Decentralized Wastewater Treatment Systems (DEWATs) in Thailand
Wastewater Management in Bangkok

Suwanna. K. Boontanon | Mahidol Univ. |6Objectives To identify the current situation of on-site treatment
methodology of black water, grey water and septage
 To confirm whether the current septic tank are constructedbased on the national guideline or not.
 To identify the attitude of residents on “Willingness to Pay”
to upgrade the domestic wastewater treatment system.

Wastewater Management in Bangkok

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Methodology
 Questionnaire surveys (301 households in Bangkok) In-depth interviews and observation with stakeholders(Pollution Control Department (PCD), Department ofDrainage and Sewerage, Bangkok Metropolitan
Administration (BMA)) Secondary data from books, published documents, online
information

Wastewater Management in Bangkok

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Suburban

Methodology: Surveys
 50 districts
 3 zones

No. ofdistricts

Population

No. ofsamples

6883,219

48

Inner city
No. ofdistricts

Population

No. ofsamples22

1,950,843

102

Inner city

Urban fringe
No. ofdistricts
22

Wastewater Management in Bangkok

Population
2,840,781

No. ofsamples151

Urban fringe
Suburban

Suwanna. K. Boontanon | Mahidol Univ. |9Grey Water Discharge

Results

 The main pathway: 77% of grey water  discharging to sewerage system.
 However most collected wastewater is mainly diverted to the water
environment nearby such as canals as they are not covered with theservice of treatment system.
Wastewater Management in Bangkok

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Black Water Discharge

Results

Commercial
septic tank

Cesspool Cesspool and septic tank is the main on-site treatment facility Commercial septic tank is installed for new households
Wastewater Management in Bangkok

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Black Water and Grey Water Pollutant Loading

Pollutant loads from grey water ismuch higher than black water

Daily amount of domestic wastewater
Wastewater Management in Bangkok

Pollutant loads (BOD) of domestic wastewater
Suwanna. K. Boontanon | Mahidol Univ. | 12

National Guideline of Targeted Wastewater| Both black water and grey water
To sewerage system
Bathing / showering

Seep intogroundToiletKitchen

Septic tank

Screener

Anaerobic filtertank

Cesspool tank

Grease Trap
Source: PCD, 2012

 In PCD manual: Both black water and grey water are recommended totreat by on-site treatment system
Wastewater Management in Bangkok

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Existing Situation : only Black Water
Grey water

Only black water is collected to treat.
Grey water management is the key issue

Wastewater Management in Bangkok

Black water

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Septage DisposalResults

 Most household interviewees at 83% used the service from Bangkok
Metropolitan Administration (BMA) for septage collection
Wastewater Management in Bangkok

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Desludging Period

Results54 % More than 50% of households do not desludge within one year
Wastewater Management in Bangkok

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Willingness to Pay

Results

75 % of this answer :willing to pay at<15,000 THB[Aerobic biofilm /Activated sludge]
30,000 – 60,000 THB

Subsidy system is really needed for
upgrading on-site treatment system
Wastewater Management in Bangkok

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Willingness to Pay:
Tariff for Wastewater Collection and Treatment

Results

 This study: range of average wastewater fee is 39-197 THB/month-house Most households (118): willingness to pay at about 89 THB/month-house
 JICA study in 2011: willingness to pay at 73.7 THB/month-house
Wastewater Management in Bangkok

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Challenges
MOI

Oversee by law

Stakeholders and Responsibilities

We do not have “law or standards” for
MONRE
MOPH
• Manufacture of septic tank
• Installation of septic tank
• Operation and maintenance• Annual water quality examination
Oversee by lawOwner

Responsible for•Document for construction•Operation (by owner)•Effluent requirements•Construction / Installation•Maintenance•Desludging

Related•Construction
Stakeholders company•Private company

government
Related Stakeholders •Local•Private company

MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health
Wastewater Management in Bangkok

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Challenges

Management and Institutional Aspect

Construction Phase

Operational Phase

Manufacturingof septic tank

Septic tankinstallation

Operation andmaintenance

Water quality
examination

Desludging

12345No standard ofproducts forcommercial
septic tanks

Permitting
control forconstruction
are week.

No regulationfor operationandmaintenanceLack ofmonitoringsystem

Integratedmanagement
between
MONRE andMOPH isneeded

6Subsidy system
for upgrading
on-sitetreatment isneededWastewater Management in Bangkok

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Conclusions
 Coverage of centralized and cluster WWTPs are low.
 No regulation especially for on-site treatment.
 Cesspool and septic tank is the main on-site treatment facility with low
treatment capability.
 Subsidy system for upgraded on-site treatment installation must beconsidered.  Proper on-site treatment system will spread rapidly insuburban areas and rural areas.
 Grey water management is the key issue for improving the situation ofwater environment.
 Surveys of “Willingness to pay” show acceptable attitude of people

Wastewater Management in Bangkok

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Recommendations
 Maintaining for the well functioning system of cluster and on-site
treatment is one of the key success  The treatment systems areexisted but the operation and maintenance are week.
 Knowledge transfer and activities to create public awareness forresidents should be implemented.
 At first, people need to involve or understand the current situation ofwater pollution and improvement measures.
 Thereafter, any implemented options either upgraded on-site
treatment or sewerage service charge will be easy to convince.

Wastewater Management in Bangkok

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Acknowledgements
 Institute for Global Environmental Strategies (IGES) for the funding
support on the project : Study on Management Framework ofDecentralized Domestic Wastewater Treatment System in Thailand Mr. Tetsuo Kuyama, IGES, who provided the great support and chance
to involve with WEPA Dr. Wilasinee Saktaywin, Environmentalist, Pollution Control Department(PCD), Ministry of Natural Resource and Environment, Thailand, whoprovided valuable comments and suggestion on this study.

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Thank you

Wastewater Management in Bangkok

Suwanna. K. Boontanon | Mahidol Univ. |