Evaluation and optimization of electrocoagulation process parameters for the treatment of oil industry drilling site wastewater

Abstract The effluent from the oil drilling site is a complex mixture of hazardous chemicals that causes environmental impacts on its disposal. The treatment of oil drill-site wastewater has not been explored much and requires understanding its characteristics and optimizing the treatment process. In the present study, we have optimized the electrocoagulation process with aluminum electrodes for drill-site wastewater treatment. A multi-level factorial center composite design using response surface methodology (RSM) is applied to optimize the effect of current density, pH, and inter-electrode distance (IED) on COD removal. The increasing current density shows a significant increase in COD removal, and a similar trend was observed with a decrease in pH. It was found that with current density and inter-electrode distance, the maximum COD removal achieved was 70% at the CD of 19.04 mA cm⁻²and IED 2.6 cm. By varying pH and current density, the COD removal reached up to 90% at pH 6 and CD 19.04 mA cm⁻². The study shows that the current density is the dominant factor for the process's energy consumption and operating cost, followed by pH. This study's findings could be effectively used for developing large-scale treatment processes through the electrocoagulation process.