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

The effluent from the oil drilling site is a complex mixture of harmful chemicals that causes environmental impacts on its disposal. The treatment of oil drilling site wastewater has not been explored in-depth in the available literature and requires understanding about its characteristics and optimization of the treatment process. In the present study, we have optimized the electrocoagulation process with aluminum electrodes for the drill site wastewater treatment. A multi-level factorial center composite design using response surface methodology (RSM) is applied to quantify the individual and combined effect of the current density, pH and inter-electrode distance (IED) on the COD removal from the drill site wastewater and the energy consumption of the electrocoagulation process. The increasing current density shows significant increase in COD removal. A similar trend was observed with decrease in pH on COD removal. The model obtained from RSM study predicted the optimum current density, pH, and IED within the experimental range of the study. It was found that the optimum condition for DSW-1 samples for 78% COD removal is at 4.76 mA/cm2 and 4 pH, and for DSW-2, we get the COD removal of 64% at 19.04 mA/cm2 and 1.2 cm IED. The study shows that the current density is the dominant factor for the process's energy consumption and operating cost as compared to the pH and IED. The study demonstrated optimization of the electrocoagulation process in drill site wastewater treatment and could be effectively used for large-scale treatment through the electrocoagulation process.