Advanced oxidation treatment of composting leachate of municipal solid waste by ozone-hydrogen peroxide

Aims: This research was conducted to investigate the efficacy and feasibility of ozone-hydrogen peroxide advanced oxidation process as a post-treatment step of composting leachate treated by an anaerobic migrating blanket reactor biological treatment system. Materials and Methods: Leachate samples was collected from the effluent of the biological treatment system and used in an ozone reactor after dilution. The effectiveness of the pH values (4.5-11.5), H²O² concentrations (0.5-4 g/L), ozone doses (0.2-1 g/h) and reaction times (5-270 min) were evaluated to determine optimum operational conditions. Results: The highest removal efficiencies were achieved 72% and 79% for chemical oxygen demand (COD) and biochemical oxygen demand5 (BOD5), respectively, at pH 8.5, 2.5 g/L H ₂ O ₂ concentration, and 1 g/h ozone dose, during 270 min reaction time. Furthermore, results indicated that the BOD ₅ /COD ratio was decreased from 0.53 to 0.4 after 270 min reaction time. Conclusions: The O ₃ /H ₂ O ₂ was found to oxidize preferably COD and BOD ₅ of the leachate samples. In consequence, a decrease in the biodegradability of leachate was observed after oxidation treatment. The O ₃ /H ₂ O ₂ reaction proved to be a feasible technique for the oxidation of the leachate under study, and it can be considered a suitable treatment for this type of wastewater.