Wastewater treatment using activated sludge entrapped in polyethylene glycol prepolymer

Immobilized activated sludge was applied to the treatment of organic wastew ater discharged from a semiconductor plant. To enhance the treatment effici ency, the growth characteristics of heterotrophic bacteria and the effect o f the BOD loading rate in continuous wastewater treatment by the immobilize d activated sludge were investigated. The activated sludge was entrapped in polyethylene glycol (PEG) prepolymer pellets. Wastewater with a BOD of 150 -200 mg/l was continuously treated in a 200-l capacity prototype reactor. T he effluent BOD concentration after treatment was 10 mg/l or less at a load ing rate of a 5.21 kg-BOD/m(3) d, representing BOD removal of 95-97%. The l ayer of heterotrophic bacteria in a pellet was 300 mu m in depth, which was thicker than that of immobilized nitrifying bacteria fed on domestic waste water.