A comparison between advanced O3/UV and H2O2/UV oxidation processes for the treatment of municipal solid waste leachate

The solid-waste leachate is a type of wastewater with high concentration of mineral and organic compounds. There is little information about the effect of the advanced oxidation processes for the treatment of municipal solid-waste leachate. Thus, this study aimed to evaluate the effectiveness of processing advanced oxidation method as a biological pre-treatment for municipal solid waste. This bench-scale experimental study was conducted in a closed batch system on leachate samples of Kahrizak landfill (Tehran). After obtaining the optimal conditions for the O3/UV and H2O2/UV processes, the effect of each process on 20 leachate samples was assessed and for each sample, 4 different reaction times were studied for the removal of BOD5, COD, TS and color. The results were compared using the mixed-design ANOVA model. The BOD5, COD and TS in raw leachate were 2500, 21910 and 29347 mg/l, respectively. The O3/UV and H2O2/UV processes removed 87% and 73% of COD, respectively. The BOD5/COD ratio in the O3/UV and H2O2/UV processes increased from 0.11 to 0.33 and 0.11 to 0.12, respectively. Moreover, the color in the O3/UV and H2O2/UV processes decreased from 82 to 67.25% and 81.65%, respectively. The O3/UV process can be used as a biological pre-treatment. The optimum pH for this process is 8.5, the optimum ozone concentration is 60.1 g/kg of decreased COD and the best reaction time which increases the BOD5/COD ratio more than 0.25 and less expensive than other reaction times, is 10 minutes.