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WEPA International Workshop | 2013 | Cambodia

On-site Treatment forDomestic Wastewaterin Thailand
Suwanna Kitpati Boontanon
Assistant Professor, Faculty of Engineering
Mahidol University
February 18, 2013

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 %of people access to sewerage system

On-site Treatmentt for Domestic Wastewater in Thailand

Suwanna. K. Boontanon | Mahidol Univ. |21

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70 % of collected night soil is
disposed to environment

30 %Sewer service area
21 %Wastewater
treatment
facility

No sewer service area

79 %On-site Treatmentt for Domestic Wastewater in ThailandNightsoil
treat‐
ment
facility

70 %Landfills, agriccultural field, waterways

BackgroundSuwanna. K. Boontanon | Mahidol Univ. |3

Key Contents of Presentation
 Management and Institutional Aspect of On-site Treatment
 Technical Aspect of On-site Treatment
 Black water and Grey water Septage Collection and Treatment

On-site Treatmentt for Domestic Wastewater in Thailand

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Management and Institutional Aspect| Law | Regulation |MOIMONRE

MOPH

Building Control Act

National Environmental Quality Act

Public Health Act(1979)(1992)(1992)

Ministerial Regulation
No. 44 (1995)

Notification for Building Effluent
Standards (2005): Standards

Ministerial Regulation
No. 51 (1998)

Notification for Building Effluent
Standards (2005): Control building A•Classified building into
type A, B, C, D, E
•On-site treatment
installation

Notification for Building
g Effluent
Standards (2011): Control building BConstruction

Effluent quality control

Ministerial Regulation(2002)•Septage collectionand charging system

Septage control

MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health
Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand

5Stakeholders and Responsibilities
MOI

Oversee byy law

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

MOPH

Oversee by lawOwner

Responsible for•Document
Dt ffor constructiont ti•Operation
Oti (by(b owner))•EffluentEfflt requirements
it•Construction / Installation•Maintenance•Desludging

Related•Construction
Stakeholders company•Private company

government
Related Stakeholders •Local•Private company

On-site Treatmentt for Domestic Wastewater in Thailand

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Funding Mechanism| Centralized and Cluster Treatment | National Funding Sources
 > 1 billion US for wastewater infrastructure in Bangkok
since 1990s
 > 500 million US for wastewater treatment plants
outside of Bangkok from 1985 to 2000
 Local Funding Sources Funding supported through Provincial Environmental
Action Plans| On-site Treatment | Owners respond for the cost of installation, operationand maintenance
Subsidy system may be needed for
upgrading on-site treatment system
On-site Treatmentt for Domestic Wastewater in Thailand

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Cost of Commercial Septic Tanks
Price (Baht) for 5 persons| Septic – Anaerobic Filter |3,000 – 12,000| Aerobic biofilm / Activated sludge |30,000 – 60,000On-site Treatmentt for Domestic Wastewater in Thailand

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Surveys of Willingness to Pay
Surveys in 2013 for 300 households
Not willing to pay
Either choice is OK
6%
6%

Pay for Upgrading the on‐sitet ttreatmentt
11 %75 % of this answer :willing
illi tto pay att<15,000 Baht

Pay for connecting to sewerage system
77 %Subsidy system is really needed for
upgrading on-site treatment system
On-site Treatmentt for Domestic Wastewater in Thailand

Suwanna. K. Boontanon | Mahidol Univ. |9Septage Collection and Charging System| Septage collection by Local Government Authorities (LGAs) | First cubic meter desludging : Charging  250 Baht/ m3
 8 USD/ m3
 Subsequent cubic meter (less than half)  150 Baht/ m3(more than half)  250 Baht/ m3
On-site Treatmentt for Domestic Wastewater in Thailand

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Surveys of Desludging Period
Surveys in 2013 for 300 households
54 % More than 50% of households do not desludge within one year
On-site Treatmentt for Domestic Wastewater in Thailand

Suwanna. K. Boontanon | Mahidol Univ. | 11Government Support: Technical Guideline| Manuals from Ministry of Natural Resources and Environment || Manuals from Ministry of Public Health |On-site Treatmentt for Domestic Wastewater in Thailand

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KEY ISSUES : Management and Institutional Aspect
Manufacturingof septic tank

Septic tankinstallation

Operation andmaintenance

Water quality
examination

Desludging

12345

No standard ofproducts forcommercial
septic tanks

Permitting
control forconstruction
are week.

No regulationfor operation
andmaintenanceLack ofmonitoring
systemIntegrated
management
between
MONRE andMOPH isneeded6
Subs dy system
Subsidysyste
for upgrading
on-sitetreatment isneededOn-site Treatmentt for Domestic Wastewater in Thailand

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Technical Aspect
Thailand | Black water and Grey water
Pollutant loads from grey water ismuch higher than black water

Daily amount of domestic wastewater
On-site Treatmentt for Domestic Wastewater in Thailand

Pollutant loads (BOD) of domestic wastewater
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Targeted Wastewater : Blackwater and Greywater
To sewerage system
Bathing / showering

Seep intogroundToilet

Kitchen

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
On-site Treatmentt for Domestic Wastewater in Thailand

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Existing Situation : only Blackwater
Grey water

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

On-site Treatmentt for Domestic Wastewater in Thailand

Black water

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On-site Treatment Systems Adopted
Cesspool (one unit or two units)• Septage is collected in cesspool.
• Liquid waste is drained into soakage pit which allow
liquid waste to seep into surrounding soil.
Septic Tank
• Septage is collected in septic tank until full and thensucked by suction truck.
• Liquid waste flows out to sewerage and drainage system
Activated Sludge• Activated sludge is used mostly in big buildings.
• Liquid waste flows out from activated sludge to sewerageand drainage system.
Suwanna. K. Boontanon | Mahidol Univ. | 17

On-site Treatmentt for Domestic Wastewater in Thailand

Percentage of On-site Treatment Systems

CommercialCi lpackage
8%
Two cesspools
23 %One cesspool
69 %Source: Dulyakasem, S., et. al., 2013. Survey of Decentralized Wastewater Treatment System (DEWATs) in Thailand – Urban
Areas
On-site Treatmentt for Domestic Wastewater in Thailand

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Water Quality : Influent and Effluent
BOD (mg/L)
Influent
Range

SS (mg/L)

Effluent

Influent

Avg.

Range

Avg.

Once cesspool

705-4,520 2,289

123-3,000

946

Two cesspools

66-6,450 2,537

25-9,517

1,436

Commercial package 519-3,075 1,783

658-1,157

849

Range

Effluent
Avg.

Range

Avg.

68-11,685 2,998 8-2,115

470

102-1,556

245

608 4-1,068

204-4,030 1,461

64-356220

Source: Dulyakasem, S., et. al., 2013. Determinations of Blackwater characteristics and sludge accumulation rates in
Decentralized Wastewater Treatment Systems (DEWATs) in Thailand
On-site Treatmentt for Domestic Wastewater in Thailand

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Septage Treatment: LGAs
| Best Practice in Treatment – Nonthaburi Municipality |The use of treated sludge as fertilizer iswidely accepted throughout Thailand Anaerobic digestion  Sludge drying beds Oxidation pond
 Transforming septage to fertilizer
On-site Treatmentt for Domestic Wastewater in Thailand

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KEY ISSUES: Technical Aspect
 Efficiency of adopted on-site treatment systems for domestic
wastewater is only 43 – 59 % removal of BOD
 Most of on-site treatment for domestic wastewater inThailand collect only “Black water”
 “Grey water” management is the key need !!

On-site Treatmentt for Domestic Wastewater in Thailand

Suwanna. K. Boontanon | Mahidol Univ. | 21Conclusions
 No standard of products for commercial septic tanks.
 Permitting control for construction and installation of septic tanks
are week.
 No regulation for operation and maintenance of on-site treatment
 Lack of monitoring system and water quality examination
 Integrated management among institutions is needed Subsidy system for upgrading on-site treatment is needed Grey water management is the key need !!

On-site Treatmentt for Domestic Wastewater in Thailand

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Thank youOn-site Treatmentt for Domestic Wastewater in Thailand

Suwanna. K. Boontanon | Mahidol Univ. |Building Effluent Standards

Source: PCD
On-site Treatmentt for Domestic Wastewater in Thailand

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Surface Water Quality

Source: PCD, 2012
On-site Treatmentt for Domestic Wastewater in Thailand

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Sewer System

Source: PCD, 2012
On-site Treatmentt for Domestic Wastewater in Thailand

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Sewer System
Combined Sewer

Sanitary
sewer

Storm sewer

Canal
Interceptor
chambers
Wastewater treatment plant

Pumping
stationChao Phraya river

Source: BMA
On-site Treatmentt for Domestic Wastewater in Thailand

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On-site Treatment

Source: PCD, 2012
On-site Treatmentt for Domestic Wastewater in Thailand

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On-site Treatment

Source: PCD, 2012
On-site Treatmentt for Domestic Wastewater in Thailand

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