Treatment of metal coating industry wastewater by electrocoagulation and electro-fenton methods

In this study, COD removal from metal plating industry wastewater was studied using electrocoagulation and electro-Fenton methods. The effects of pH, current density, conductivity, and distance between electrodes were investigated by the electrocoagulation method and optimum experimental conditions were determined. In the optimum conditions determined in this context (pH: 6,01, current density: 200 A/m2, distance between electrodes: 0,9 cm, conductivity: 5000 μS/cm, stirring speed: 250 rpm, reaction time: 80 min.), maximum of 46,5% COD removal was achieved with electrical energy consumption of 7,6 kWh/m3. The final treatment cost, calculated from the sum of the anode and electrical energy consumption for COD removal, was calculated as 69,57 TL/m3 of wastewater and 210,81 TL/ kg of COD per kg of COD. The effects of pH, H2O2 concentration, current density and distance between electrodes were investigated by the electro-Fenton method. Optimum conditions (pH: 3, H2O2: 1500 mg/L, current density: 150 A/m2, distance between electrodes: 1,25 cm, conductivity: 5000 μS/cm, stirring speed: 250 rpm, reaction time: 40 min.) were determined. A maximum of 82,16% COD removal was achieved with an electrical energy consumption of 3,24 kWh/m3. The total treatment cost for COD removal was 631,83 TL/m3 of wastewater and 1116,30 TL/ kg of COD per kg of COD. It was found that the COD removal efficiency was higher with the electro-Fenton method.