Study On Groundwater Environmental Impact Assessment And Prediction For Datang Cogeneration Project In Binzhou Based On MODFLOW

Groundwater environmental impact assessment and prediction paly an important role in the conservation of groundwater environment during the establishment and operation of construction projects.Numerical simulations were conducted in this study to predict the influence to groundwater flow and solute transport from a thermal power plant refered to as Datang Cogeneration Project in Binzhou.The evaluation work for groundwater environmental impact was carried out by Shandong Monitoring Center of Geo-Environment.The groundwater quality in the area where the project is located is poor and low in development and utilization.Normally,the the wastewater and domestic sewage of the project is recycled and reused,and the circulating cooling water is discharged from the sewage pipe network of the factory to the north city wastewater treatment plant of Binzhou.The groundwater would not be polluted unless under an abnormal condition such as leaking of the oil tank and sewage treatment station,the firing and exposing of the liquid ammonia tank and the leaking of the ash field.This study was carried out on the basis of several field hydrogeological investigations including plant hydrogeological survey,hydrogeological drilling,seepage test and etc.By analyzing the plant hydrogeological conditions and the characteristics of the project,a hydrogeological conceptual model and the corresponding numerical simulation model of groundwater flow were established.The simulation of groundwater flow was implemented by the software MODFLOW.The validated numerical model can reflect the groundwater flow system.A solute transport model was established with the potential pollutants as the simulation factors.The migration of pollutants wss predicted in different simulation conditions in the study area by the solute transport model,and the prediction analysis of the pollution risk was carried out.The main conclusions were:1)the influence circle of oil as one category of pollutions will expand to 3096m~2 and the maximum migration distance is 63m after30 years under the condition of turbine oil pool leakage accident.The oil consistency is not exceeding the standard udring the simulation period.2)The influence circle of COD beyond the range of standard as well as COD which below the standard but can be detected as a category of pollutions will insde the edge of the grid of the pollution source within 30 years in the case of the sewage treatment station leaking.3)the influence circle of Fluorine as a category of pollutions will be 348,437m~2 and the circle of Fluorine beyond the range of standard will be195,090m~2 under the ash field leakage condition without impermeable layer.The maximum migration distance is 69m which is inside the plant edge.4)There will not have poluution be detected and beyond the standard in concentration under the scenario that leakage in the impermeable layer of the ash field.5)The influence circle of liquid nitrogen as a category of pollutions will reach up to 116,874m~2 with a 84,182m~2 area of beyond standard concentration in 30 years if there is an accident leakage of the liquid ammonia tank.The maximum migration distance of the pollution plume will be 87m but insde the plant edge.