Study On The Evaluation Method Of Wastewater Treatment Process In Small Towns Based On AHP And BP

At present,the sewage treatment system of small towns in China is imperfect,and its construction speed has lagged behind the demand of economic development.It causes serious pollution of water around small towns,resulting environmental deterioration.Therefore,there is an urgent need to speed up the construction of sewage treatment plants in small towns.The key to the construction and operation of sewage treatment plants is the sewage treatment technology.This paper will focus on the evaluation methods of sewage treatment technology in order to improve the evaluation system in this field.Firstly,based on the analysis of the development status of sewage treatment plants,sewage treatment technology and their evaluation methods in small towns in China,this paper introduces the problems existing in the application of sewage treatment technology,and expounds the importance of comprehensive evaluation of sewage treatment technology.Secondly,after determining the factors that may affect the selection of sewage treatment technology in small towns,this paper establishes a comprehensive system of three layers and fourteen indicators of sewage treatment technology by using analytic hierarchy process.The specific indicators are:BOD removal rate,COD removal rate,NH₃-N removal rate,TN removal rate,TP removal rate,SS removal rate,shock load resistance capacity,project investment,operation cost,land area,excess sludge,noise,difficulty in reconstruction and expansion,difficulty in operation and management,etc.Also,the weight relationship of each index in the comprehensive system was analyzed.Finally,using MATLAB as the data analysis platform,this paper establishes a BP neural network model to analyze the sewage treatment technology in small towns comprehensively,and forms a set of relatively perfect comprehensive evaluation index system.Taking 17 small town sewage treatment processes as examples,it uses the above evaluation methods to evaluate these processes comprehensively.The comprehensive evaluation system based on analytic hierarchy process?AHP?and BP neural network?BP neural network?overcomes the subjective factors to a certain extent.It can deal with complex problems hierarchically,logically,systematically and mathematically.On the basis of using the characteristics of biological nervous system,it can carry out self-learning and self-correcting.This comprehensive evaluation method can provide a certain basis for the optimal election of the small-scale sewage treatment process.