Study On The Evaluation Of Comprehensive Performance Of Rural Domestic Sewage Treatment Process Based On The Grey Correlation-TOPSIS Model

With the promotion of urban infrastructure and the promotion use of wastewater treatment technologies, urban domestic sewage treatment rate continues to increase. However, in rural areas, due to the limitation of its geographical conditions and economic factors, domestic sewage treatment rate is far below the urban domestic sewage treatment rate, rural domestic sewage issue has become an important part of rural sewage treatment.2005release of "Chongming Master Plan (2005-2020)" clearly states want to build a modern ecological island in Chongming, which will bring endless opportunities and economic development in future, but at the same time, the environment is also proposed to a higher demand. Rural sewage treatment is an important part of water environmental governance, but rural domestic sewage treatment rate in Chongming is less than20%.Chongming carry out the pilot project of rural domestic sewage treatment since2008, then gradually expand the scope.In this study, set the rural domestic sewage treatment project in Chongming as the research object. After introduce the overall progress of rural domestic sewage treatment project and the application of treatment process in Chongming, filter out fourteen indicators from economic benefits, technical performance, environmental benefits, and management efficiency, consisting of evaluation indicator system. Coupled entropy weight, gray correlation analysis, TOPSIS method, establish a comprehensive evaluation model of Gray Correlation-TOPSIS to evaluate the effectiveness of rural sewage domestic treatment process in Chongming, provide the basis for future options.The main conclusions of the paper are summarized as follows:(1) Summarize the overall progress of rural domestic sewage treatment projects, comb the application of rural domestic sewage treatment process in Chongming. Concluded as follows:①At the end of2012, totally completed rural domestic sewage treatment of27,639farmers, established treatment systems373, totally carried out10rural domestic treatment processes.②The technology applicability of biotypes and biotypes+ecotypes treatment process are relatively good, the economic applicability of biotypes+ecotypes treatment process is general, the technical applicability of ecotypes treatment process is general, but has better economic applicability.(2) Based on the evaluation result of rural domestic sewage treatment process by Grey Correlation-TOPSIS model in Chongming, get the following conclusions:①Use Grey Euclid-TOPSIS model to evaluate the relatively close between the three kinds of rural domestic sewage treatment process with the ideal solution, the order is C3>C2>C1. That is the Integrated Membrane Bioreactor performance optimization, followed by the New Composite Biofilter+High Load wetland, and finally Comprehensive Artesian Oxygen Increasing Artificial Ecosystem Bed. Use Grey Minkowski-TOPSIS model to evaluate the relatively close between the three kinds of rural domestic sewage treatment process with the ideal solution, the order is C2>C3>Ci. That is the New Composite Biofilter+High Load wetland performance optimization, followed by the Integrated Membrane Bioreactor, and finally Comprehensive Artesian Oxygen Increasing Artificial Ecosystem Bed.②According to the Gray-Euclid and Gray-Minkowski formula indicates, since Euclid distance expanded the influence of weights to the results, use grey Minkowski-TOPSIS model to evaluate the relative merits of the extent of the gap between the three kinds of rural domestic sewage treatment process is smaller than gray Euclid-TOPSIS model evaluation, to make the results more comparable, so the application of gray Minkowski-TOPSIS model better evaluate the merits of treatment process. According to Grey Minkowski-TOPSIS model to evaluate the relatively close between the three kinds of rural domestic sewage treatment process with the ideal solution, the order is C2>C3>C1.So the comprehensive performance of the New Composite Biofilter+High Load_wetland (biotypes+ecotypes) is higher than the Integrated Membrane Bioreactor (biotypes) and the Comprehensive Artesian Oxygen Increasing Artificial Ecosystem Bed (ecotypes). The comprehensive performance of the Integrated Membrane Bioreactor (biotypes) is higher than the Comprehensive Artesian Oxygen Increasing Artificial Ecosystem Bed (ecotypes).③Gray Correlation-TOPSIS model can elaborate the difference between the change trends of internal factors of sample and the ideal sample, can effectively avoid the data to be compared with reference data located sequences to be compared with the above data sequence located below have the same or similar correlation(3) When selecting rural domestic sewage treatment process in the future, the following points should be paid attention to:①Water source protection areas has higher environmental requirements, large scale rural domestic sewage treatment in this regional, recommend the use of bio type+ecotype treatment process, and the treatment of small scale in this regional, recommended biotype treatment process;②Large scale rural domestic sewage treatment in non-water source protection areas, when meet the requirements of economy and technology, recommend to use biotype treatment process, also recommend combined treatment process. The treatment of small scale in this regional, recommended ecotype treatment process, but should be added a preprocessor facilities.