Supercritical Water Oxidation of Sewage Sludge: Effect of Temperature and Pressure on Organic Destruction

Abstract

The disposal and treatment of sewage sludge generated from municipal wastewater treatment plants present significant environmental and operational challenges due to the high concentration of organic pollutants, pathogens, and hazardous compounds. The present study investigates the application of supercritical water oxidation for the effective destruction of organic matter in sewage sludge, with particular emphasis on the influence of temperature and pressure on oxidation efficiency and process performance. Experimental analysis was conducted under varying supercritical conditions to evaluate organic degradation, chemical oxygen demand reduction, reaction kinetics, and thermal conversion characteristics. Results indicate that elevated temperature and pressure conditions substantially enhance oxidation reactions by improving mass transfer, oxygen solubility, and free radical formation within the supercritical water medium. The study demonstrates that higher operating temperatures accelerate the decomposition of refractory organic compounds, leading to significant reductions in sludge volume and pollutant concentration. Pressure optimization further contributes to stable reaction conditions and improved oxidation efficiency, minimizing incomplete combustion byproducts and secondary waste generation. In addition, the process exhibits rapid reaction rates and effective pathogen destruction, supporting its suitability for advanced sludge treatment applications. Comparative assessment with conventional sludge disposal and thermal treatment technologies reveals superior organic destruction efficiency, reduced environmental emissions, and enhanced energy recovery potential. The findings highlight the capability of supercritical water oxidation as a sustainable and environmentally efficient technology for sewage sludge management and resource recovery. The study contributes to the advancement of high-performance wastewater treatment systems and supports the development of cleaner environmental engineering practices for modern urban sanitation infrastructure.