Impact of electrodes' configuration in an electrokinetic cell for oil-water separation

Abstract The discharge of large volumes of oily wastewaters without sufficient treatment poses a huge risk on the environment. The main objective of this study was to investigate the capability of electro-coagulation/flotation (ECF) process for the removal of oil from industrial oily wastewater via different electrodes' configuration. These included anode-cathode-anode-cathode (ACAC), anode-cathode-cathode-anode (ACCA), and cathode-anode-anode-cathode (CAAC) electrode configurations. The impact of other operational conditions such as treatment time (30, 60, and 90 min), current density (50, 100 and 200 A/m2), and initial pH (4, 7, 10) was also investigated. Results showed that the up to 30.3% increase in oil removal can be achieved by optimizing the treatment time in the ACCA configuration. Similarly, it was found that operating at higher CD higher than 100 A/m2 resulted in a minor increase in oil removal in the same configuration. Optimal oil removal efficiency of 82% was achieved when the ECF system operated at a current density 100 A/m2, a treatment time of 90 min, an initial wastewater pH of 7, and using ACAC electrodes' configuration. An operational electrical energy consumption of 3.4 kWh/m3 and a treatment cost of USD 0.26/m3 were also reported for this configuration. It was concluded that oil removal using ECF process are very sensitive to changes in the electrode configuration, and an optimum configuration can be chosen by considering the time and cost of treatment.