Treatment of copper wastewater using optimal current electrochemical–coagulation

Abstract

In this study, an automatic current controlling electrochemical-coagulation (EC) process was developed by testing laboratory-scale and pilot-scale reactors for removing copper (Cu) from printed circuit board (PCB) industrial wastewater with an economic use of energy. During tests of the laboratory-scale reactor, the influences of electrode material, electrode gap, current density, hydraulic retention time (HRT), wastewater pH and conductivity on removal performance were explored. The relational expression between conductivity and current density that optimizes Cu removal based on conductivity changes was established and applied to the optimal current EC process. During tests of the pilot-scale reactor, Cu removal from PCB industrial wastewater was investigated by applying an automatic current controlling system for the EC process. More than 90% of the Cu was removed when applying optimal current control for the EC process in both laboratory-scale and pilot-scale experiments, which demonstrated significant energy savings.