Water Volume- and BOD- based Flow Analysis for Domestic Wastewater Treatment Using Wastewater Inventories of Bangkok, Thailand

Urban population, it is predicted that, will reach at 5 billion by 2030 and 95% of urban expansion in the next decades will take place in developing countries. In addition, it is indicated that rapid urbanization brings pressures on freshwater supply and sewage treatment. Then sustainable development goal 6 shows 8 targets to ensure availability and sustainable management of water and sanitation for all, and intends to increase proportion of population using safely managed sanitation services, wastewater safely treated and bodies of water with good ambient water quality. Bangkok, which is the capital of Thailand, has 8 centralized sewage treatment plants (CSTP) designed to treat domestic wastewater of approximately a half of residents. However, water quality of some canals in the area provided with sewage works (APSW) has not been improved well, and the cause is not found out due to uncertainty of flows of domestic wastewater. Thus, this study has identified flows of domestic wastewater by an inventory approach to estimate volume of wastewater and biochemical oxygen demand (BOD) discharge based on population distribution in Bangkok. As the results, it is estimated that 75% of BOD discharged in APSW does not reach CSTP.