Performance of electrocoagulation process for copper removal in simulated artisanal and small-scale mining wastewater

Abstract

Electrocoagulation treatment was applied in the simulated artisanal and small-scale mining wastewater for 60 minutes. Copper concentration of 625 mg.L−1 was used in the study which was based on the real artisanal and small-scale mining wastewater (conductivity = 13 mS.cm−1, initial pH = 10) collected from Paracale, Camarines Norte, Philippines. Batch experiments using a pair of iron electrodes with an interelectrode distance of 2 cm were used for this study and we have determined the optimized conditions such as conductivity, initial pH, and current density for the various electrocoagulation runs. Decreasing initial conductivity and pH of real mining wastewater while increasing current density favours higher removal efficiency. With the conductivity of 3.5 mS.cm−1, initial pH of 9, and current density of 33.5 mA.cm−2, copper removal efficiency was 93.5%. Based on these operating conditions, energy consumption was 36.82 kWhr.m−3 and electrodes consumption were 2.09 kg.m−3. This study revealed that electrocoagulation is feasible to treat higher concentrations of copper present in mining wastewater.