ABSTRACT
The treatment of synthetic oily wastewater having the characteristics of a typical petroleum refinery wastewater (PRW) by electrocoagulation (EC) using iron and aluminum electrodes was conducted in an electrolytic reactor equipped with fluid recirculation. During the treatment, the emulsion stability was followed by the measurement of Zeta potential and particle sizes. Effects of some operating conditions such as electrodes material, current density and electrolysis time on removal efficiencies of turbidity, and chemical oxygen demand (COD) were investigated in detail. The PRW purification by the EC process was found to be the most effective using aluminum as the anode and cathode, current density of 60â A/m(2) and 30â min of electrolysis time. Under these conditions, the process efficiencies were 83.52% and 99.94%, respectively, for COD and turbidity removals which correspond to final values of 96â mg O2/L and 0.5 NTU. A moderate energy consumption (0.341â kWh) was needed to treat 1â m(3) of PRW. Besides, the ecotoxicity test proved that toxic substances presented in the PRW, and those inhibiting the germination growth of whet, were eliminated by the EC technique.