Study on Treating Dyeing and Finishing Wastewater with Combined Process of Anaerobic-PAC-SMBR

Submerged membrane bioreactor was used to investigate dyeing and finishing wastewater. Considering its unique characteristics, anaerobic process was carried out before membrane bioreactor, and powdered activated carbon was added to the reactor in order to change the property of the mixed liquor. Combination of the three processes above constituted combined process of Anaerobic-PAC-SMBR, by which the reduction of pollution indexes in wastewater during each treatment unit and the property of membrane fouling in the system were studied. The results showed that under the optimum conditions the COD_Cr content in effluent water was approximately 120 mg/g, removal rate of ammonia nitrogen was 93%, the chrominance was lower than 5 times, the turbidity was less than 30 FTU, and the suspended substance was zero. Addition of powdered activated carbon effectively altered the characteristic of the mixed liquor, and alleviated the membrane fouling, so it facilitated the cleaning of the membrane and the recover of the membrane flux. Combined process of Anaerobic- PAC-SMBR exhibited excellent treatment effect and stability to dyeing and finishing wastewater.