Suwanna Kitpati Boontanon
Faculty of Engineering, Mahidol UniversityNovember 28, 2014
Wastewater Managementin Bangkok
WEPA | SEAWE11 | 2014 | Thailand
Assistant Professor
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Stabilization Pond
(45%)
Aerated Lagoon
(16%)
Activated Sludge
(36%)
Wetland (2%) Rotating Biological
contactor (1%)
Types of Centralized Wastewater Treatment system in ThailandBackground
Source: Saktaywin, W., 2013. WEPA workshop, Cambodia
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Background
Thailand : 14 million m3/d of wastewater generated
3 million m3/d of treatment capacity
3
21 % of people access to sewerage system
Bangkok : 2.6 million m3/d of wastewater generated
1 million m3/d of treatment capacity
40 % of people access to sewerage system
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Background
4
Sewer service area
No sewer service area
21 %
79 %
Wastewater treatment facility
Centralized & Cluster WWTPs
Night soil treat‐mentfacility
Land
fills, agricultural field, w
aterways
On‐site
30 % 70 %
On‐site
70 % of collected night soil is disposed to environment
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 5
Background Coverage of Wastewater Treatment Plants in Bangkok
•Huamark•Klong Chan
•Rom Klao
•Bangna•Klongtoey
•Raminthra
•Thasai•Thung Songhong I•Thung Songhong II•Bangbua
•Bonkai
•Huay Khang
Inner city Urban fringe Suburban Centralized WWTPCluster WWTP
1
2 3
45
6
78
1) Si Phraya Wastewater Treatment Plant
2) Rattanakosin Wastewater Treatment
plant
3) Din daeng Wastewater Treatment Plant
4) Chongnonsi Wastewater Treatment
Plant
5) Nong Khaem Wastewater Treatment
Plant
6) Thungkru Wastewater Treatment Plant
7) Chatujack Wastewater Treatment Plant
8) Bang Sue Environmental Conservation
and Learning Center
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 6
Source: Dulyakasem, S., et. al., 2013. Determinations of Blackwater characteristics and sludge accumulation rates in Decentralized Wastewater Treatment Systems (DEWATs) in Thailand
Background On-Site Water Quality: Influent and Effluent
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
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 constructed based on the national guideline or not.
To identify the attitude of residents on “Willingness to Pay” to upgrade the domestic wastewater treatment system.
7
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Methodology
Questionnaire surveys (301 households in Bangkok)
In-depth interviews and observation with stakeholders (Pollution Control Department (PCD), Department of Drainage and Sewerage, Bangkok Metropolitan Administration (BMA))
Secondary data from books, published documents, online information
8
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Methodology: Surveys
9
50 districts
3 zones
Inner city
Urban fringe
Suburban
No. of districts
Population No. of samples
22 1,950,843 102
No. of districts
Population No. of samples
6 883,219 48
No. of districts
Population No. of samples
22 2,840,781 151
Suburban
Inner city
Urban fringe
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 10
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 the service of treatment system.
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 11
Black Water Discharge Results
Cesspool and septic tank is the main on-site treatment facility Commercial septic tank is installed for new households
Commercial septic tank
Cesspool
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 12
Daily amount of domestic wastewater Pollutant loads (BOD) of domestic wastewater
Pollutant loads from grey water is much higher than black water
Black Water and Grey Water Pollutant Loading
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
National Guideline of Targeted Wastewater
13
In PCD manual: Both black water and grey water are recommended to treat by on-site treatment system
Bathing / showering
Kitchen
ToiletSeptic tank Anaerobic filter
tank Cesspool tank
Screener Grease Trap
To sewerage system
Seep into ground
Source: PCD, 2012
| Both black water and grey water
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Existing Situation : only Black Water
14
Grey water
Black waterOnly black water is collected to treat.Grey water management is the key issue
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 15
Septage Disposal Results
Most household interviewees at 83% used the service from Bangkok Metropolitan Administration (BMA) for septage collection
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 16
More than 50% of households do not desludge within one year
54 %
Desludging Period Results
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 17
Subsidy system is really needed for upgrading on-site treatment system
75 % of this answer : willing to pay at <15,000 THB
30,000 – 60,000 THB
[Aerobic biofilm / Activated sludge]
Willingness to Pay Results
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 18
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
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Challenges
19
MOI MONRE MOPH
Oversee by lawOwner
•Document for construction
•Construction / Installation
•Operation (by owner)
•Maintenance
•Effluent requirements
•Desludging
Responsible for
Oversee by law
We do not have “law or standards” for • Manufacture of septic tank• Installation of septic tank• Operation and maintenance• Annual water quality examination
Related Stakeholders Related Stakeholders•Construction
company•Private company •Local government
•Private company
Stakeholders and Responsibilities
MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok 20
No standard of products for commercial septic tanks
Manufacturing of septic tank
Septic tank installation
Operation and maintenance DesludgingWater quality
examination
1Permitting control for construction are week.
2No regulation for operation and maintenance
3
Subsidy system for upgrading on-site treatment is needed
6
Lack of monitoring system
4Integrated management between MONRE and MOPH is needed
5
Construction Phase Operational Phase
Challenges Management and Institutional Aspect
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Conclusions
21
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 be considered. Proper on-site treatment system will spread rapidly in suburban areas and rural areas.
Grey water management is the key issue for improving the situation of water environment.
Surveys of “Willingness to pay” show acceptable attitude of people
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Recommendations
22
Maintaining for the well functioning system of cluster and on-site
treatment is one of the key success The treatment systems are
existed but the operation and maintenance are week.
Knowledge transfer and activities to create public awareness for
residents should be implemented.
At first, people need to involve or understand the current situation of
water pollution and improvement measures.
Thereafter, any implemented options either upgraded on-site
treatment or sewerage service charge will be easy to convince.
Suwanna. K. Boontanon | Mahidol Univ. |Wastewater Management in Bangkok
Acknowledgements
23
Institute for Global Environmental Strategies (IGES) for the funding
support on the project : Study on Management Framework of
Decentralized 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, who
provided valuable comments and suggestion on this study.