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

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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 m

3 _{/d of wastewater generated}

3 million m

3 _{/d of treatment capacity}

21 %

of people access to sewerage system

 Bangkok : 2.6 million m

3 _{/d of wastewater generated}

1 million m

3 _{/d of treatment capacity}

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Background

Sewer service area

30 %

70 %

70 % of collected night soil is

disposed to environment

No sewer service area

21 %

Wastewater treatment

facility Night _soil treat‐ ment facility

cultur

al

field,

wa

te

rw

ay

s

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

3 79 %

Landfills,

agri

c

Key Contents of Presentation

 Management and Institutional Aspect of On-site Treatment

 Technical Aspect of On-site Treatment

 Black water and Grey water

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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

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

5

MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health

Construction

Effluent quality control

Septage control

g

Standards (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 examination

y

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

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

7 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

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Surveys of Willingness to Pay

Surveys in 2013 for 300 households

Pay for Upgrading the on‐site

t

Not willing to pay

Either choice is OK

75 % of this answer :

illi

t

Pay for connecting to sewerage system

77 %

treatment

11 %

Either choice is OK

6 %

willing to pay at

<15,000 Baht

9 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/ m

3  8 USD/ m

3  Subsequent cubic meter (less than half)  150 Baht/ m

3

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Surveys of Desludging Period

Surveys in 2013 for 300 households

54 %

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

Government Support: Technical Guideline

| Manuals from Ministry of Natural Resources and Environment |

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KEY ISSUES :

Management and Institutional Aspect

Manufacturing

of septic tank

Septic tank

installation

Operation and

maintenance

Desludging

Water quality

examination

1

2

3

4

5 No standard of

products for

commercial

septic tanks

1 Permitting

control for

construction

are week.

2 No regulation

for operation

and

maintenance

3 Subsidy system

6 Lack of

monitoring

system

4 Integrated

management

between

MONRE and

MOPH is

needed

5

13 Subs dy syste

for upgrading

on-site

treatment is

needed

Technical Aspect

Thailand | Black water and Grey water

Pollutant loads from grey water is

much higher than black water

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Targeted Wastewater :

Blackwater and Greywater

Bathing / showering

To sewerage system

Toilet

Septic tank Anaerobic filter

tank Cesspool tank

Seep into ground

15  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 water

Only 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.

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

17 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

19

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 |

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 BOD

 Most of on-site treatment for domestic wastewater in

Thailand collect only “Black water”

 “Grey water” management is the key need !!

21 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

(12)

Thank you

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Surface Water Quality

25

Source: PCD, 2012

Sewer System

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Sewer System

Storm sewer Sanitary

Combined Sewer

Canal Interceptor chambers sewer Pumping station Wastewater treatment plant

27

station

Chao Phraya river

Source: BMA

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On-site Treatment

29