Tran Thi Hong Nhien creator Visvanathan, C. Chairperson Chongrak Polprasert Examination Committee Fujii, Shigeo Examination committee Swedish International Development Agency (SIDA) Scholarship donor text series technical report th Bangkok Asian Institute of Technology 1993 continuing eng 107 leaves + 1 online resource A biological aerated filter combines bacterial degradation of pollutant by fixed biomass with physical filtration in a single reactor. An organic removal process has been operated on an experimental basis at a pilot plant over five months at the AIT - Environmental Engineering Division Laboratory. The wastewater feed was modified AIT domestic wastewater. The process consists of a granular media bed, particularly of polystyrene (thus, named biostyr process) with a specific gravity of approximately 0.06. The cylindial reactor was 4 m high and 0.2 m diameter. Headloss measurement was studied as a function of wastewater temperature, velocity and time. Experiments were conducted at 30°C, 38°C, 45°C and 55°C with velocities of 2 m/h, 4 m/h, 6 m/h and 8 m/h respectively. At 38°C, filtration time range was 5.5-10 hours and over 84% of the soluble COD was removed at all velocities investigated. At 30°C, 75.8- 89.4% COD removal was noticed, 89.4% COD removal with the exception of 6 m/h velocity and 8.5 hour filtration time. At 45 °C, 77.1-87.9% of soluble COD was removed, in which 87.9% COD removal could be obtained at 2 m/h velocity with a filtration time of 40 hours. A decreasing gradient of biomass from bottom to top of the reactor was observed. 2- 5.8% of purified water was consumed for backwashing operation. The optimal suspended solids removal occurred at 30°C with 6 m/h velocity. At lower temperature, maximum suspended solid removal could be obtained. The results indicated that effluent SS could be less than 30 mg/L, that is secondary treatment effluent standard in Thailand. A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering Thesis (M.Eng.) - Asian Institute of Technology, 1993 Sewage Purification Biological treatment Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B16681 http://203.159.5.9/ait-thesis/detail.php?q=B16681 230399 20260817162952.0