Bangkok Wastewater Project, Stage IV

The scheme included a wastewater treatment plant with sludge treatment facilities to treat a dry weather flow of 150,000 m³/d and serve an existing population of ca. 550,000, plus industrial wastewater and infiltration summing up to a PE of 1 million at an average flow of 150 l/h/d. The project also included the construction of 28 km of sewers with up to 2,500 mm diameter, together with pumping stations and associated rising mains totalling a further 10 km.

The wastewater treatment plant, which, due to severe space restrictions, was built as a 4 storey plant over a Klong, includes inlet pumping station, preliminary and secondary treatment using sequencing batch reactors, sludge thickening, digestion and dewatering. The wastewater is treated to a high standard with nitrogen and phosphorus removal. Sequencing batch reactors were designed to accommodate higher flows by changing the cycle time and providing additional mechanical plant. The plant is fully automated and includes SCADA.