Electrocoagulation treatment of oily wastewater using perforated electrodes: Process optimization via response surface methodology

Abstract

Oily wastewater poses a significant environmental concern due to its high chemical oxygen demand (COD) and complex composition, which limits the effectiveness of conventional treatment methods. In the present study, an electrocoagulation (EC) process employing perforated electrodes was investigated for the effective removal of COD from oily wastewater. A direct current (DC) power supply was used to operate the EC reactor, and process optimization was performed using response surface methodology (RSM) based on a box–behnken design (BBD). The influence of three key operational parameters, namely, initial pH, current density, and electrolysis time, on COD removal efficiency was systematically evaluated. The results revealed that electrolysis time was the most influential parameter, followed by current density and pH. At the central levels of pH and current density, a treatment duration of 25 minutes resulted in approximately 72% COD removal. The optimized operating conditions were identified as pH 5.42, current density of 5 mA/cm², and electrolysis time of 25 minutes, under which a maximum COD removal efficiency of 91.81% was achieved with a specific energy consumption of 1.835 kWh/m³. The findings demonstrate the effectiveness of the electrocoagulation process with perforated electrodes and highlight its potential application as a decentralized treatment option for complex oily wastewater streams.