ABSTRACT
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
ABSTRACT
Solid waste management is considered to be one of the most immediate and serious environmental problems confronting urban governments in developing countries. Qualitative and quantitative variety of waste composition, uncontrolled urban development and the lack of appropriate waste management technology cause particular problems that solving them needs a careful study and the coordination of science and experience in the form of a proper management. This descriptive study was carried out on solid wastes generated in Kashan over a limited timeframe of 12 months during 2009-10. One sample was randomly taken per month according to the standard instruction and subsequently the physical analysis of it was performed. The average daily waste generation rate in Kashan is 185 tons, of which 75.5% are putrescible materials. The average daily waste generation is tantamount to 638 g/capita while the average density of the waste 194 kg/m[3] at transfer station. The most frequent metal measured in the leachate solid waste was iron. According to the results high percentages of solid wastes in Kashan were allocated to plastic and corruptible materials, and then the paper and cardboard. Considering that the prevention of adverse environmental effects of solid waste is a priority and applying proper management techniques can help to achieve this, public education for the waste separation at the source, waste reduction and subsequently reduction of the leachate volume as well as the proper manner of recycling, collection and disposal of the waste are recommended