wastewater management in bangkok - water … management in bangkok suwanna. k. boontanon | mahidol...

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


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


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


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


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


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


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


6 883,219 48

No. of districts


22 2,840,781 151

Suburban

Inner city

Urban fringe


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.


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


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


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


Existing Situation : only Black Water

14

Grey water

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


Septage Disposal Results

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


More than 50% of households do not desludge within one year

54 %

Desludging Period Results


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


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


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


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


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


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.


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.


Thank you

wastewater management in bangkok - water … management in bangkok suwanna. k. boontanon | mahidol...

Documents