Treatment of carwash wastewater by electrocoagulation using Ti electrode: optimization of the operating parameters

Abstract

Electrocoagulation process using Ti electrode was employed for carwash wastewater treatment. Taguchi experimental design method was applied to identify the optimized values of operating parameters for chemical oxygen demand, anionic surfactant and oil–grease removals. The effects of operating parameters on the removal of selected pollutants were investigated. The operating variables were selected as pH: 4–8; current density: 2.5–30 A/m2; stirring speed: 150–350 rpm. 84% chemical oxygen demand, 99.3% anionic surfactant and 82% oil–grease removal efficiencies were achieved under the optimized conditions. The operating cost was calculated as 9.67 $/m3 for these conditions. The analysis of variance results indicated that the current density had the greatest effect on the removals. EC sludge produced at the optimum conditions was analyzed using environmental scanning electron microscopy–energy-dispersive X–ray and Fourier transform infrared spectroscopy analyses. The results indicated that Taguchi design method was suitable to determine the optimum values of operating parameters for EC treatment of carwash effluents. High chemical oxygen demand, anionic surfactant and oil–grease removals showed that electrocoagulation process using Ti electrode can be used for the removal of organic matters from carwash effluents.