Continuous‐flow microwave enhanced oxidation process for treating sewage sludge

Abstract

AbstractThe microwave‐enhanced advanced oxidation (MW/H2O2‐AOP) treatment of sewage sludge in a continuous‐flow 915 MHz microwave system was studied. A higher H2O2 dosage at the same flow rate resulted in better solids disintegration in terms of higher soluble chemical oxygen demand. The highest soluble chemical oxygen demand concentration of 5174 mg/L was obtained at a dosage of 0.005 L/L (0.5 % v/v). A higher soluble chemical oxygen demand was obtained at a higher flow rate with the same H2O2 dosage. A substantial amount of soluble phosphorus (over 60 % of total phosphorus content) was produced for all treatments, regardless of H2O2 dosage. A first‐order reaction kinetics of soluble chemical oxygen demand was proposed in this study. Real‐time energy consumption corresponding to performance efficacy, which provides a realistic assessment of the process efficiency, was calculated. Energy consumption was found to vary between 0.22–0.29 kWh/L of sludge treated. The results demonstrated that a continuous‐flow 915 MHz microwave system resulted in high treatment efficiency in terms of nutrient release, solids disintegration, and low energy consumption, which is suitable for real‐time industrial applications.