Simulation for migration and treatment of groundwater contamination in coal mining subsidence area: A case study of Datong dump, Huainan, China

Abstract

The liquid that seeps into the earth from landfills and removes garbage is called landfill leachate. Pollutants like organic and inorganic chemicals, xenobiotic substances, etc. are found in landfill leachate which contaminates groundwater. To study the contamination and treatment of landfill leachate to groundwater, Datong landfill was selected as a target zone. Samples of monitoring wells in the landfill site, the eastern collapse pond, and wells in groundwater from the goaf were tested and analyzed for TDS, conductivity, and dissolved oxygen (DO). To simulate all processes, various modules were built under different conditions. It was found that the leachate not only had polluted surface water but also groundwater. The simulation results showed that the pollution plume expanded spatially and temporally, mainly flowing from west to east and spreading to the north-south direction and reverse flow direction due to the low water level between the east and west sides. Anti-seepage walls and pumping-injection methods were used to control the migration and diffusion of pollution from landfill leachate. The simulation results also showed that both methods were effective in reducing the concentration and range of pollution plumes which would provide a theoretical basis for the treatment of pollutants in the Datong landfill site.