Groundwater Environmental Impact Simulation And Evaluation Of Hazardous Waste Landfill

With the development of the national economy,resulting in increasing the amount of hazardous waste,hazardous waste are toxic,flammable,explosive,corrosive,chemically reactive or infectious,not only pollute the air,water and soil,but also through various channels,destroying the environment and harm to human health.The current use of disposal technology for its is security landfill.However,hazardous waste landfill leachate generated in the landfill stage,and once its occurrence leakage,the leachate pass through the barrier layer and the unsaturated zone into groundwater,solute transport in groundwater with the surrounding groundwater environment pollution will risk.Taking Hexi area hazardous waste disposal center project as an example,through the study area to carry out environmental and hydrogeological investigations of groundwater monitoring and evaluation of the water quality situation,access to basic geological data Area of the proposed project to determine the potential of the project on groundwater environment influences.For the protection of groundwater resources and the environment,prevention of groundwater contamination,the paper carried out the appropriate work and conclusions are as follows:In this paper,maximum,minimum,over standard rate,the maximum over standard multiples of different types of groundwater were alysised.by standard index method,the environmental quality of different types of groundwater in the evaluation area was evaluated comprehensively.The results showed that the groundwater quality does not meet the standard requirements of Ⅲ water quality in "groundwater quality standards"(GB / T14848-93).The total hardness,total dissolved solids,ammonia and chloride of phreatic water were over the standars;pH,total dissolved solids,ammonia and chloride of confined water were over the standars.Excessive ammonia and about the life of local residents,chloride,total dissolved solids,total hardness,pH and excessive local native geological environment.Based on geological conditions of the proposed project,establishing a one-dimensional vertical vadose zone saturated-unsaturated soil water movement equation(Richards equation),using the no-lag effect Van Genuchten-Mualem model to simulate the flow of water transport in the vadose zone.According to the porous media solute transport theory,given the saturation of the soil to absorb-mathematical model of solute transport in unsaturated soil,modeling the pollutant migration law in the vadose zone,the results showed that the occurrence of various pollutants in seepage at 23,300 days(63 years)after reaching confined aquifer,the maximum concentration of pollutants at 29,000 days(79 years).Establishing the evaluation hydrogeological conceptual model and solute transport model and using simulation software GMS to predict migration and transformation of pollutants in confined water aquifer.In the simulation period,the hazardous waste site in the leakage of leachate confined aquifer pollution,and the emergence of the phenomenon of excessive,the migration of contaminants into the confined aquifer 100 years later,the maximum contaminant migration distance of about 2.8km,the front end of the plume from the nearest point of the sensitive tiansheng spring about 12 km,not downstream born spring duck pond and reservoir affected.