Mixed dye wastewater treatment in a bioelectrochemical system-centered process.

The feasibility of mixed dye wastewater treatment was evaluated with a novel integrated bioprocess that consisted of a hybrid anaerobic reactor (HAR) with a built-in bioelectrochemical system, an aerobic biofilm reactor (ABFR) and a denitrification reactor (DR). The position of the DR significantly affected chemical oxygen demand (COD) and colority in effluent, and placing the DR after the ABFR improved effluent quality probably due to minimization of the undesired autoxidation of aromatic amine in dye wastewater. The optimal integrated process of HAR + ABFR + DR efficiently treated mixed dye wastewater, and concentrations of COD and TN were decreased down to 75 ± 18 mg/L and 12.91 ± 0.31 mg/L, respectively, along with colority 48 ± 4 times. Total phosphorus reduced to below 0.5 mg/L with coagulation using poly aluminum chloride, and the effluent quality fully met the discharge standard. This comprehensive study suggests the feasibility of the BES based process for practical application to mixed dye wastewater treatment.