Electro-oxidation of phenol in petroleum wastewater using a novel pilot-scale electrochemical cell with graphite and stainless-steel electrodes

This work investigated the removal of phenol from petroleum wastewater by the electro-oxidation process. The experimental design was developed on a pilot-scale electro-oxidation system equipped with a cylindrical shape of graphite electrodes as an anode and stainless-steel electrodes as a cathode. An initial study was performed based on operating variables such as current density and time on real petroleum wastewater. The optimum conditions were obtained as a current density of 3 mA/cm(2)and time 15 min. Under these applied optimum conditions, complete phenol removal from an initial concentration of about 6.8 mg/L was achieved. Also, 50-60% removal of organic matter in terms of chemical oxygen demand (COD) and biological oxygen demand (BOD). The removal of organic matter using electro-oxidation requires a long reaction time. Also, the economic study indicated that the energy consumption was determined to be 0.79 kWh/m(3)and the operating cost was 0.051 $/m(3)which is very economical compared with conventional methods.