Response surface modeling of COD removal from metal cutting wastewaters via electrooxidation process: Effect of direct photovoltaic solar panel on energy consumption

Today, water and wastewaters are effectively treated with many treatment technologies. However, there are deficiencies in the integration of treatment technologies with renewable energy sources. In this study, the integration of solar energy, one of the renewable energy sources, into electrooxidation (EO) process, which is one of the new generation advanced wastewater treatment techniques, is provided. Parameters affecting the EO process such as pH, current density (C.D.) and electrolysis time (E.T.) was optimized by Box Behnken Design (BBD) on elimination of soluble Chemical Oxygen Demand (sCOD) from metal processing wastewater. The study also tried to determine the optimum conditions for the treatment of metal processing wastewater with EO process by developing different scenarios. The scenario in which the energy requirement was 18.33 kWh/m3 3 and the COD removal efficiency was 75.23%, i.e. the scenario that maximizes the COD removal efficiency and minimizes the energy consumption (E.C.), is considered to be appropriate. In this case, the optimum pH for the EO process was 5, C.D. was 80 A/m(2), E.T. was 22.15 minutes with a desirability of 1. At the optimum conditions (for the 2 nd scenario), the E.C. of the EO process was fulfilled from solar panel in a ratio of 15% and 318% in overcast and sunny weather, respectively. Thus, it has been determined that the solar panel integrated EO process is an approach that reduces E.C. and accordingly operating cost, and also has the potential to obtain enough energy to be stored especially in sunny weather.