Study On Numerical Simulation Of Groundwater Pollution In A Coal-fired Power Plant

China is a country with abundant high quality coal resources,because of its low required geographical conditions,short construction period,the mature technology,and advantages of small investment,coal is the main power source of electric industry in China,accounting for over 60% of the total output.Coal-fired power plants would inevitably discharge wastewater during operation time,and abnormal condition of sewage leakage would pose a threat to the groundwater environment,so before power plant set up,the prediction and evaluation for pollution factor,pollution range,and the concentration of the pollutants with the change rule of space and time is very necessary to provide reasonable advice.This paper take a coal-fired power plant as research object,collect information of meteorology,geology,hydrogeology and so on,analysis of the hydrogeological conditions and the present situation of development and utilization of groundwater,the hydrogeological conceptual model is set up,study area was divided into Yalu River alluvial plains,tributary intermontane valley area and hilly region;According to the characteristics of aquifer and the water content,it is divided into three aquifers: shallow unconfined aquifer,weak permeable layer and deep confined aquifer;According to the hydrogeological test,hydrodynamic conditions boundary conditions,the hydrogeological parameters of the model and the calculated source sink items,finally generalize the model into heterogeneity and anisotropic of three dimensional unsteady flow.The finite difference method is selected to solve the problem.By using application of GMS software MODFLOW(water)module and MT3D(solute)module,set up corresponding mathematical model of groundwater flow and solute transport respectively,and by using the observation period measured water level data to identify and verify the model,calibration period is 86 days,verification period is 60 days,finally adjust parameter to get a better simulation effect,calculated and analysis water balance.Set up solute transport model based on water flow model,select ammonia nitrogen,chloride ion,petroleum,fluoride,arsenic,COD as predict factors,predicted 100 days,1000 days,7300 days pollute situation.According to different degree of pollution it can be divided into safety area,influence area,sensitive area and,to analyze the results of evaluation: with longer time,the effects of pollutants on the groundwater environment will gradually expand,but in the case of without taking anti-seepage measures,the entire area did not excessive area during the running,only a few pollution factor appear small sensitive area,but under seepage control measures,sensitive area were getting smaller.Therefore,the pollutants leakage under abnormal working conditions will not cause damage to the groundwater environment,but it's also important to pay attention to the effects of COD and oil leakage on the adjacent supply well.In the end,the prevention and control suggestions are put forward for the potential accidents of power plant.