Investigation into the electrocoagulation treatment of wastewater from a zinc plating plant in Kastamonu province

The aim of this study was to remove chemical oxygen demand (COD) and zinc from metal plating wastewater using electrocoagulation technique. For this purpose, a reactor with two anodes and cathodes made of iron was used. The results showed that the removal efficiency of COD and zinc increased with increasing electrocoagulation (EC) experiment duration and current density. The optimum conditions for experiment 7 were determined as initial pH value 3, current density 1.5 A, experiment duration 56.32 minutes and power consumption 7.1 kWh/m3. Under these conditions, the maximum COD and zinc removal rates were found to be 63.38% and 99.99%, respectively. In order to examine the effects of initial pH, current and time in the EC process, a statistical model was developed with three-level factors using a central composite design. The R2 values of the developed model were 0.9900 for power consumption, 0.9714 for COD removal and 0.8896 for zinc removal, which were well fitted to polynomial mathematical second order equations. Analysis of variance (ANOVA) revealed that pH, current and time had significant effects and these parameters were significant because the p-value was less than 0.05. In general, it was concluded that electrocoagulation process can be used for pollutant removal of metal plating wastewater.