Investigation of the parameters affecting the treatment of mining waters by electrocoagulation

Recently electrochemical methods have been studied as an alternative to conventional methods to treat industrial and municipal waters. One such water, the mining water, has been mainly treated previously by electrocoagulation (EC) to remove metals. Few studies have been performed on the removal of sulfate, nitrate and cyanide from mining waters. In this paper, results from 39 lab-scale experiments on the elimination of sulfate by electrocoagulation with iron electrodes are presented. Significance of parameters affecting the removal of sulfate by EC was studied using response surface methodology (RSM). Also, results from kinetic studies and comparison of synthetic and real mining waters are reported. According to kinetics studies, it was suggested that both physical and chemical mechanisms are involved in sulfate removal. At the same test conditions, sulfate removal from both synthetic and real mining waters followed the same pattern. The study concludes that the most significant parameters in sulfate removal are initial sulfate concentration and applied current when initial pH was insignificant in batch operation. From a technology development perspective, this study enhances knowledge about the significance of process parameters and their interactions as well as allows further scale-up of the process