| With the continuous development of our economy and the continuous improvement of people’s living quality, city life garbage accumulation is increasing, and the cumulative heap amount of garbage is more than 60 hundred million tons one year, which has seriously affected the people’s living environment and lead to garbage leachate in the process of landfill of garbage.Garbage leachate is one kind of organic wastewater of high concentration and difficult to handle. Its composition is complicated and imbalance between microbial nutrition elements ratio is serious.The change of water quality of water is big,and it has strong toxic hazardous,and these characteristics make the leachate treatment is one worldwide problem.Therefore, according to the characteristics of leachate and specific water quality characteristics, exploring the optimal treatment scheme is to accelerate the leachate treatment effect in the field of shortcut, which has important research significance.In view of the research object- one city garbage leachate treatment plant,in this paper,the formation mechanism and source of leachate are expounded, and on the basis, the characteristics of leachate and the water quality evaluation are studied.The factors that affect leachate composition and properties are explored,then research status of leachate at home and abroad are analyzed, and the leachate biological, chemical and natural ecological treatment are introduced.According to the research results of leachate forecast methods at home and abroad,on the basis of the principle of profit and loss and the principle of water balance,the paper enumerat three kinds of methods of leachate: water balance method, empirical statistical method and empirical formula method.Generally,the project recommend the annual average daily rainfall referencing empirical statistical method for leachate production prediction.Applying this method to the research object-one municipal waste leachate treatment plant, the output is forecasted,and the result is 74m3/d,so leachate design production is 80m3/d. This paper introduces the basic principle of analytic hierarchy process and basic steps, and its application in the leachate treatment plant is introduced in detail, for later leachate scheme provides theory basis for comparison.Based on the water quality characteristics of municipal garbage leachate, the traditional simple combination of physical and chemical and biological technology is very difficult to achieve discharge standard,and according to existing domestic and foreign multiple combination of film processing technology of leachate treatment plant, water quality has reached the emission standards, by the leachate of actual engineering case study and experience at home and abroad, puttingforward two alternatives: A2/O-MBR + RO and Two levels A/O-MBR + DTRO.Through to the mentioned rule of 11 factors and analysis of two given scheme,using the Analytic Hierarchy Process(AHP) in economic and technical aspects of the two alternatives comparison,and considering its works in leachate quality and technique feasibility of the comparison result,and the optimal scheme is concluded:Two levels A/O-MBR +DTRO.Based on Huang Kai Jian’s pilot experiment study of waste leachate, and the two levels of A/O-MBR for COD and NH3-N and BOD5 grading removal effect of the contrast analysis, finally, we confirm the two levels of A/O pool allocation removal rate of organic matter is: the first level of A/O: COD is 82%,BOD is 95%,and NH3-N is 94%; the second level A/O: COD is 50%,BOD is 75%, and NH3-N is 76%.Through the study of nitrifying bacteria survive temperature and the local temperature climate factors of project, the leachate design temperature is 20 ℃.Finally, on the basis of considering the consumption, fully considering the rationality, economy and feasibility of the project, for the Two levels A/O-MBR+DTRO,we determine the parameters of the regulation pool, two levels A/OMBR biochemical pool,ultrafiltration system,and DTRO system. |
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