WEPA International Workshop 2013 Cambodia On-site Treatment for Domestic Wastewater in Thailand Suwanna Kitpati Boontanon Assistant Professor, Faculty of Engineering Mahidol University February 18, 2013 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 40 % of people access to sewerage system On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 2 1
Background Sewer service area 70 % of collected night soil is disposed to environment 30 % 70 % 21 % No sewer service area 79 % Wastewater treatment facility Night soil treatment facility Landfills, agric cultural field, waterways On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. 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 Suwanna. K. Boontanon Mahidol Univ. 4 2
Management and Institutional Aspect Law Regulation MOI MONRE MOPH Building Control Act National Environmental Quality Act Public Health Act (1979) (1992) (1992) Ministerial Regulation No. 44 (1995) Ministerial Regulation No. 51 (1998) Classified building into type A, B, C, D, E On-site treatment installation Notification for Building Effluent Standards (2005): Standards Notification for Building Effluent Standards (2005): Control building A Notification for Building Effluent Standards (2011): Control building B Ministerial Regulation (2002) Septage collection and charging system Construction Effluent quality control Septage control MOI: Ministry of Interior; MONRE: Ministry of Natural Resources and Environment; MOPH: Ministry of Public Health On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 5 Stakeholders and Responsibilities Oversee by law We do not have law or standards for MOI Manufacture of septic tank MONRE MOPH Installation of septic tank Operation and maintenance Annual water quality examination Oversee by law Owner Responsible for Document for construction ti Operation (by owner) Effluent requirements Construction / Installation Maintenance Desludging Related Stakeholders Construction company Private company Related Stakeholders Local government Private company On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 6 3
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, operation and maintenance Subsidy system may be needed for upgrading on-site treatment system On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 7 Cost of Commercial Septic Tanks Septic Anaerobic Filter Price (Baht) for 5 persons 3,000 12,000 Aerobic biofilm / Activated sludge 30,000 60,000 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 8 4
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 site treatment t t 11 % 75 % of this answer : willing to pay at <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. 9 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 (more than half) 250 Baht/ m 3 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 10 5
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. 11 Government 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 Suwanna. K. Boontanon Mahidol Univ. 12 6
KEY ISSUES : Management and Institutional Aspect Manufacturing of septic tank Septic tank installation Operation and maintenance Water quality examination 1 2 3 4 5 No standard of products for commercial septic tanks Permitting control for construction are week. 6 Subsidy system for upgrading on-site treatment is needed No regulation for operation and maintenance Lack of monitoring system Desludging Integrated management between MONRE and MOPH is needed On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 13 Technical Aspect Pollutant loads from grey water is much higher than black water Thailand Black water and Grey water Daily amount of domestic wastewater Pollutant loads (BOD) of domestic wastewater On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 14 7
Targeted Wastewater : Blackwater and Greywater Bathing / showering To sewerage system Toilet Septic tank Anaerobic filter tank Cesspool tank Seep into ground Kitchen Screener Grease Trap Source: PCD, 2012 In PCD manual: Both black water and grey water are recommended to treat by on-site treatment system On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 15 Existing Situation : only Blackwater Grey water Only black water is collected to treat. Grey water management is the key issue Black water On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 16 8
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 Activated Sludge Activated sludge is used mostly in big buildings. Liquid waste flows out from activated sludge to sewerage and drainage system. On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 17 Percentage of On-site Treatment Systems Commercial package 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 Suwanna. K. Boontanon Mahidol Univ. 18 9
Water Quality : Influent and Effluent BOD (mg/l) SS (mg/l) Influent Effluent Influent Effluent 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 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 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 19 Septage Treatment: LGAs Best Practice in Treatment Nonthaburi Municipality The use of treated sludge as fertilizer is widely accepted throughout Thailand Anaerobic digestion Sludge drying beds Oxidation pond Transforming septage to fertilizer On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 20 10
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!! On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 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 Grey water management is the key need!! On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 22 11
Thank you On-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 Suwanna. K. Boontanon Mahidol Univ. 24 12
Surface Water Quality Source: PCD, 2012 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 25 Sewer System Source: PCD, 2012 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 26 13
Sewer System Combined Sewer Sanitary sewer Storm sewer Canal Interceptor chambers Wastewater treatment plant Pumping station Chao Phraya river Source: BMA On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 27 On-site Treatment Source: PCD, 2012 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 28 14
On-site Treatment Source: PCD, 2012 On-site Treatmentt for Domestic Wastewater in Thailand Suwanna. K. Boontanon Mahidol Univ. 29 15