An Optimization Methodology Of Groundwater Remediation Technologies Of Contaminated Sites In The Desert Areas By Multi-Criteria Decision Analysis

Because of the appeared frequently problem of groundwater pollution in the desert which caused by polluting enterprises to underground drainage, the chemical plant pollution of groundwater in Tenggeli desert region as a case study, it put forward optimization method that is suitable for remediation technology of groundwater pollution in the desert area.The groundwater contamination risk zonation is determined from GIS graph characteristics and by evaluating the groundwater vulnerability and identifying the contamination source features of this region and the objectives and scope of groundwater restoration are then found for this region.On the basis of comprehensive consideration of economic, technological and social benefits of rehabilitation technology, using AHP establish the index system,and using the elimination and transformationmethod(ELECTREII) in MCDA to prioritize for combination of repair technologyto different schemes are obtained, so as to choose the optimal solution.The results show that:(1)According to the results of the groundwater pollution risk screening value of chlorinated benzene, benzene, p-dichlorobenzene, of nitrochlorobenzene, nitrophenol, neighbouring nitrophenol, p-nitrophenyl methyl ether and adjacent amino benzene methyl ether 8 kinds of pollutants to groundwater pollution risk zoning target pollutants.(2)The groundwater vulnerability index between 6.5 and 7.2, the overall trend in the southeast, northwest low.Regional groundwater aquifer vulnerability rating for the strong vulnerability, sensitivity was highly contaminated.Multi-index evaluation method is used to determine the groundwater pollution index in the study area, the southeast of chemical pollution pollutants highest risk index, pollution effect obviously, smaller risk index gradually from southeast to northwest of pollutants, pollution affects more and more low.(3)Composition characterized by GIS, the risk of groundwater partition I, II level is defined as the area defining area of high risk of contamination, III, IV-class district of pollution risk areas.(4)Analytic Hierarchy Process(AHP) to determine the index weight, where economic, technical indicators, social weight of the three factors were 0.1047,0.6370,0.2583. Experts generally indicate a chemical plant in the desert groundwater remediation technology screening technical factors of most concern, followed by social benefits, and finally economic benefits.(5) Through improved ELECTERII methods of Five groundwater remediation technology selection, to obtain the advantages of the net value:c 0.850、c2.106、c 1.158、c 1.278、c 2.863. PRBsis the best in five kinds of repair techniques.(6)Finally considering the chemical plant contaminated sitescharacteristics and groundwater management requirements, the best solution is: for high pollution area use P& T(Pump & Treat)+ Fenton advanced oxidation+ PRBs groundwater remediationtechnique for joint repair, for low pollution area use Enhanced Monitored Natural Attenuation technology.