on-site treatment for domestic wastewater in thailand

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WEPA International Workshop | 2013 | Cambodia

On-site Treatment for Domestic Wastewater

in Thailand

Suwanna Kitpati Boontanon

Mahidol University

February 18, 2013

Assistant Professor, Faculty of Engineering

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

Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand 2

40 % of people access to sewerage system

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Background

Sewer service area30 % 70 %

70 % of collected night soil is disposed to environment

No sewer service area

21 %

Wastewater treatment facility

Night soil treat‐mentfacility

cultural field, w

aterw

ays


79 %

Landfills, agric

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


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Management and Institutional Aspect| Law | Regulation |

MOI MONRE MOPH

Building Control Act National Environmental Quality Act Public Health Act

Ministerial Regulation (2002)

Notification for Building Effluent

Notification for Building Effluent Standards (2005): Control building A

Notification for Building Effluent Standards (2005): Standards

Ministerial Regulation No. 51 (1998)

Ministerial Regulation No. 44 (1995)

Building Control Act

(1979)

National Environmental Quality Act

(1992)

Public Health Act

(1992)

•Classified building into

•Septage collection and charging system

Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand 5MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health

Construction Effluent quality control Septage control

gStandards (2011): Control building B

•Classified building into type A, B, C, D, E

•On-site treatment installation

Stakeholders and Responsibilities

MOI MONRE MOPH

Oversee by law 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 examinationy

Owner

D t f t ti O ti (b ) Effl t i t

Responsible for

Oversee by law


•Document for construction

•Construction / Installation

•Operation (by owner)

•Maintenance

•Effluent requirements

•Desludging

Related Stakeholders Related Stakeholders•Construction

company•Private company •Local government

•Private company

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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


Action Plans

| On-site Treatment |

Owners respond for the cost of installation, operation and maintenance Subsidy system may be needed for

upgrading on-site treatment system

Cost of Commercial Septic Tanks

| Septic – Anaerobic Filter |

Price (Baht) for 5 persons

| Aerobic biofilm / Activated sludge |

3,000 – 12,000


30,000 – 60,000

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Surveys of Willingness to Pay

Surveys in 2013 for 300 households

Pay for Upgrading the on‐site

t t t

Not willing to pay

Either choice is OK75 % of this answer :

illi t t

Pay for connecting to sewerage system

77 %

treatment 11 %

Either choice is OK6 %

6 %willing to pay at

<15,000 Baht


Subsidy system is really needed for upgrading on-site treatment system

Septage 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

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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

Government Support: Technical Guideline

| Manuals from Ministry of Natural Resources and Environment |


| Manuals from Ministry of Public Health |

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KEY ISSUES : Management and Institutional Aspect

Manufacturing of septic tank

Septic tank installation

Operation and maintenance

DesludgingWater quality examination

1 2 3 4 5No standard of products for commercial septic tanks

1Permitting control for construction are week.

2No regulation for operation and maintenance

3

Subsidy system

6

Lack of monitoring system

4Integrated management between MONRE and MOPH is needed

5


Subs dy systefor upgrading on-site treatment is needed

Technical AspectThailand | Black water and Grey water

Pollutant loads from grey water is much higher than black water


Daily amount of domestic wastewater Pollutant loads (BOD) of domestic wastewater

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Targeted Wastewater : Blackwater and Greywater

Bathing / showering

To sewerage system

ToiletSeptic tank Anaerobic filter

tankCesspool tank

Seep into ground


In PCD manual: Both black water and grey water are recommended to treat by on-site treatment system

Kitchen Screener Grease Trap Source: PCD, 2012

Existing Situation : only Blackwater

Grey water

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


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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.liquid waste to seep into surrounding soil.

Septic Tank

• Septage is collected in septic tank until full and then sucked 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 sewerage

and drainage system.

Percentage of On-site Treatment Systems

C i l

One cesspool

69 %

Two cesspools

23 %

Commercial

package

8 %


Source: Dulyakasem, S., et. al., 2013. Survey of Decentralized Wastewater Treatment System (DEWATs) in Thailand – Urban Areas

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Range Avg. Range Avg. Range Avg. Range Avg.

Once cesspool 705-4,520 2,289 123-3,000 946 68-11,685 2,998 8-2,115 470

BOD (mg/L)

Influent Effluent

SS (mg/L)

Influent Effluent

Water Quality : Influent and Effluent

Two cesspools 66-6,450 2,537 25-9,517 1,436 102-1,556 608 4-1,068 245

Commercial package 519-3,075 1,783 658-1,157 849 204-4,030 1,461 64-356 220


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

Septage Treatment: LGAs

| Best Practice in Treatment – Nonthaburi Municipality |


Anaerobic digestion Sludge drying beds Oxidation pond

Transforming septage to fertilizer

The use of treated sludge as fertilizer is widely accepted throughout 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 BODwastewater is only 43 – 59 % removal of BOD

Most of on-site treatment for domestic wastewater in

Thailand collect only “Black water”

“Grey water” management is the key need !!


Conclusions

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 !!

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Thank you

Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand

Building Effluent Standards

Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand 24Source: PCD

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Surface Water Quality

Suwanna. K. Boontanon | Mahidol Univ. |On-site Treatmentt for Domestic Wastewater in Thailand 25Source: PCD, 2012

Sewer System


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Sewer System

Storm sewerSanitary

Combined Sewer

Canal

Interceptor chambers

sewer

Pumping station

Wastewater treatment plant


station

Chao Phraya river

Source: BMA

On-site Treatment


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On-site Treatment


on-site treatment for domestic wastewater in thailand

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