| With the rapid development of urbanization in China,the total amount of urban sewage discharge remains high,environmental protection funds have been pouring into the construction of sewage treatment facilities,and the number of urban sewage treatment plants in China has increased year by year.However,how to evaluate the comprehensive use of the technology used in these sewage treatment plants,how to guide the selection of new sewage treatment plants and how to give full play to the effectiveness of investment funds are still the key and difficult points to be faced.Based on the project of"evaluation and demonstration of key technology of sewage treatment in river basin"in the national water pollution prevention and control science and technology major project,and based on the report data of urban sewage treatment plant operation obtained from the relevant departments of the Ministry of Ecological Environment,this paper sorts out the main types of urban sewage treatment technology in China,determines the comprehensive evaluation index system of urban sewage treatment technology,and constructs the comprehensive evaluation index system,stablished the comprehensive evaluation model of urban sewage treatment technology,and the main urban sewage treatment technology in China are comprehensively evaluated from three dimensions of environment,economy and operation management.The main research results are as follows:(1)The comprehensive evaluation index system of urban sewage treatment technology is established.The paper establishes a comprehensive evaluation index framework of urban sewage treatment technology:one evaluation objective,three criteria of"environment-economy-operation management",six elements of"environmental effect-secondary pollution-use cost-economic benefit-operational reliability-operational applicability".Through the frequency analysis,importance judgment,availability judgment and independence test of comprehensive evaluation index system of urban sewage treatment technology,the index layer index screening method was used to screen54 alternative indexes.The indexes of COD removal rate,ammonia nitrogen removal rate,TN removal rate,TP removal rate,sludge production per ton of water,investment cost per ton of water,operation cost per ton of water,operation income per ton of water,operation stability and load rate are obtained.The comprehensive evaluation index system of urban sewage treatment technology is obtained by combining the comprehensive evaluation index framework of urban sewage treatment process with the 10 index layer indexes selected.(2)The weight of the evaluation index is determined and the comprehensive evaluation model of the urban sewage treatment technology is established.The paper uses AHP and entropy weight method to calculate the index weight in the form of subjective and objective combination.By calculating the comprehensive weight of indicators in the indicator layer,it is found that the influence of each indicator on the evaluation results from large to small is:TN removal rate,sludge production per ton of water,operation stability,operation cost per ton of water,investment cost per ton of water,load rate,TP removal rate,operation income per ton of water,ammonia nitrogen removal rate and COD removal rate.Based on the weight of each index at each level,the comprehensive evaluation model of urban sewage treatment technology is constructed by using the comprehensive index method.(3)The comprehensive evaluation of the main urban sewage treatment technology in China is carried out.The results show that the comprehensive performance of the sewage treatment technology in China from high to low is A~2/O,SBR,Biological Aeration Filter,Oxidation Ditch,MBR,Rotating Biological Contactor,A/O,Biological Contact Oxidation and Constructed Wetland technology;in which A~2/O,SBR,Biological Aeration Filter and Oxidation Ditch technology have better comprehensive performance in environmental,economic and operation management dimensions,there are shortcomings and no outstanding characteristics in Constructed Wetland,Rotating Biological Contactor,Biological Contact Oxidation and A/O treatment technology;MBR technology has distinct characteristics,with obvious advantages in environmental dimension and obvious disadvantages in economic dimension.(4)The comprehensive evaluation of the main sewage treatment technology in China is carried out by region and year.The results show that:the comprehensive utilization of the main urban sewage treatment technology in China is obviously different in different regions,according to the comprehensive evaluation results,the recommended technology in Northeast China is Oxidation Ditch technology,the recommended technology in North China is Biological Aeration Filter technology,the recommended technology in Northwest China,East China and Central China is A~2/O technology,and SBR technology is recommended in South China and Southwest China;the comprehensive use effect of the main sewage treatment technology in China is better year by year. |
PDF Full Text Request