Experimental study on optimization of chemical oxygen demand reduction through advanced oxidation process for refinery-based oily sludge in Barmer Rajasthan, India

Abstract

This study investigates the optimization of chemical oxygen demand (COD) reduction in oil refinery sludge using advanced oxidation processes (AOPs), addressing the pressing need for effective and sustainable wastewater treatment technologies. AOPs, known for their capacity to degrade complex organic pollutants, are explored under varying operational parameters, including pH, hydrogen peroxide (H₂O₂) dosage, ferrous sulfate (FeSO₄) concentration, and stirring time. The methodology involves controlled batch experiments to evaluate the individual and combined effects of these parameters on COD reduction efficiency.  The study demonstrates that acidic conditions (pH 1.5) and an optimized H₂O₂ dosage of 100 ml/L achieves a maximum COD reduction of 57%. Stirring time is found to significantly influence the treatment process, with 90 minutes of stirring under optimal conditions yielding the best results. The inclusion of FeSO₄ as a catalyst provides limited enhancement, highlighting the need for further exploration of its role. The research identifies diminishing returns at higher reagent concentrations, emphasizing the importance of parameter optimization to balance efficacy and cost. The study is perhaps the first one of its kinds carried out in the western Rajasthan where a new petroleum refinery in Barmer district is getting ready for its operation very soon.  The findings reveal that AOPs can effectively reduce COD in wastewater when operated under specific conditions, offering a sustainable approach for pollution control. Future work should focus on scaling the process for industrial applications, understanding the by-products formed, and investigating synergistic effects of catalysts to enhance performance. This research contributes to advancing wastewater treatment practices in line with global sustainability goals.