Abstract：Response surface methodology (RSM) was employed to optimize the treatment processes of kaolin suspension and digested swine wastewater by the complex of broth produced by Rhodococcus erythropolis and either PAC or modified zeolite. Flocculating rate, floc size, COD and ammonium removal rates were settled as the target responses. As the determination coefficients (R2) of 0.8933, 0.8353, 0.7819 and 0.8343, the quadratic models could agree with experimental data well. Results showed that the optimal flocculating conditions for kaolin suspension were broth dosage of 3.7mL/L, PAC dosage of 49mg/L, CaCl2 dosage of 24 mg/L, pH=8.7 and contact time of 15 min, and the corresponding flocculating rate and floc size were 96.3% and 0.67mm. The optimal conditions for digested swine wastewater treatment were broth dosage of 4.5mL/L, modified zeolite dosage of 12 g/L, CaCl2 dosage of 16 mg/L, pH=8.3 and contact time of 55 min, and the corresponding removal rates of COD and ammonium were 87.9% and 86.9%.
