Abstract:Response surface methodology(RSM) was applied for optimizing the enhanced coagulation process by preozonation for Taihu lake water.Based on single-factor experiments

three independent variables(ozone dosage

coagulant dosage and residence time) were selected as affecting factors and three dependent variables(chemical oxygen demand(CODMn) removal efficiency

turbidity removal efficiency and operating cost) as responses.An experimental design of three factors and three levels was arranged through Box-Benhnken design (BBD).According to the proposed quadratic models

maximal CODMnand turbidity removal efficiencies and minimal operating costs are obtained at following optimum condition:The ozone dosage

coagulant dosage and residence time are found to be 0.9 mg/L

35 mg/L and 17 min for aluminum sulfate(AS) and 0.9 mg/L

24 mg/L

and 17 min for polymerization aluminum chloride(PAC)

respectively.