ComGIS-based Simulation And Prediction Of Groundwater Pollution In Landfill Site

A landfill in Fengtai District of Beijing was taken as the research object,based on the collection,collation and analysis of hydrogeology and water quality monitoring data in the study area,a conceptual model of hydrogeology was constructed,and a numerical simulation model of shallow underground aquifer water and solute transport simulation model were established.Under the premise of ideal identification and verification of the flow numerical model,the migration rule of ammonia nitrogen and nitrate nitrogen in groundwater was simulated and predicted.Using Visual Studio 2010 and C#language based on the.NET Framework 3.5 to modularize the groundwater flow and water quality simulation model.The components were divided into map control component,aquifer system component,spatiotemporal dissection component,source and sink component,mathematical model component,definite solution component and visual component.The components were integrate with ArcEngine seamlessly,a groundwater pollution simulation and forecasting system framework was developed,and the environmental impact analysis and visual display of groundwater pollution in landfills were performed.Analysis of the pollution situation in the study area from 2008 to 2020 shows:1.The water quality continued to deteriorate,and the proportion of monitoring sites with poor water quality levels increased from 25%in 2008 to 62.5%in 2020.2.Ammonia nitrogen and nitrate nitrogen pollution plume migrated to the southeast as a whole and their maximum lateral distance,maximum longitudinal distance and contaminated area continued to increase.The average diffusion rate of ammonia nitrogen and nitrate nitrogen in the maximum lateral distance is 7.83m/a and 25.75m/a,the average diffusion rate of the maximum longitudinal distance is 121.67m/a and 192.17m/a,and the average diffusion rate of the contaminated area is 0.06 km~2/a and 0.22km~2/a.3.Pollution of ammonia nitrogen plumes cause pollution to residential areas from 2012 onwards.A total of 2 residential areas will be affected by 2020.The affected residential area will be 0.1km~2.Contaminated plumes of nitrate nitrogen will affect residential areas from 2011 onwards.Water pollution causes a total of 4 residential areas to be affected by 2020.The affected residential area is 0.37 km~2.The research results provide a reference for the treatment of leachate leakage and protection of groundwater resources in the landfill.