Continuous treatment of biologically treated textile effluent using a multi-cell electrochemical reactor

The refractory components of textile wastewater usually cannot be effectively removed using biological methods. In this paper, the electrochemical treatment of biologically treated textile effluent was investigated using a continuous multi-cell reactor. The operational variable effects were firstly examined using the wastewater which was obtained by diluting the raw textile wastewater to a chemical oxygen demand (COD) level close to the biologically treated effluent. The proper current density and retention time were found to be about 12 mA cm−2 and 30 min, respectively. The biologically treated effluent was then treated under the proper conditions above. The reactor performed quite well. The COD of the wastewater could be reduced from 238-249 mg L−1 to 43-54 mg L−1; the effluent pH ranged from 6.37 to 6.48; the color of the wastewater turned from brown to transparent; the current efficiency and energy consumption were 42.5-43.6% and 16.2-16.6 kWh m−3, respectively. In addition, it was demonstrated that the electrode dissolution was not significant. The effluent Pb content was below the permissible value of the discharge standard of China, 0.1 mg L−1. The experimental results clearly indicate that the multi-cell electrochemical reactor is a good alternative for the treatment of biologically treated effluent.