Development of a Combined Electrocoagulation and Electrochemical Oxidation Reactor for Treating Service Station Effluent

Abstract

Effluents generated from service stations contain several categories of pollutants such as detergents, oil and grease, organic materials, and heavy metals. Most of the literature suggests the electrochemical methods as effective and sustainable methods to treat such wastewater. This research focuses on removing total suspended solids (TSS), oil and grease (O&G), and chemical oxygen demand (COD) from both synthetic and actual service station wastewater samples by using an electrochemical cell carrying a novel anode. An aluminium anode was used to support electrocoagulation (EC), while a copper-plated graphite anode was used to support electrochemical oxidation (EO). Two separate batch reactors were tested initially for individual EC and EO efficiencies of treating the targeted pollutants for 40 min of reaction time under a current density of 30 mA/cm². The EO efficiencies of removing TSS, O&G, and COD were increased by 21%, 56.3%, and 29.2%, respectively, from the modification of graphite by copper-plating. The efficiency study of the combined reactor with both EC and EO anodes was carried out under two approaches, i.e., the constant current study and constant time study, in order to investigate the optimum operating conditions. TSS, O&G, and COD removal efficiencies of 100%, 100%, and 99.4% were achieved respectively under a reaction time of 60 min at a constant current density of 20 mA/cm² for synthetic wastewater. The efficiency study of the electrochemical cell carried out under the optimum operating conditions for actual service station effluent resulted in TSS and O&G removal of 100% and COD removal of > 99%. Therefore, the developed combined reactor carrying novel electrodes can be suggested as an efficient treatment method for the treatment of service station effluent.