Study On Groundwater Environmental Impact Of A Thermal Power Plant Construction In Xinjiang

ZhunDong region in Xinjiang is very rich in coal resources, and is also one of the four major national planning coal bases in Xinjiang. Data collection and field ground investigation were used to identify hydrogeology and environmental geology conditions of the study area based on Tianchi Energy Zhundong Wucaiwan Coal-Electricity Integrated Complex Projects. Vadose zone contaminant transport numerical simulation model was established on the basis of development of hydrogeology and environmental geology investigation, geophysical prospecting, pitting, drilling, water seepage test, indoor dispersion experiment, soil and water sample collection and analysis, groundwater monitoring and indoor data analysis. Non-normal conditions were simulated to predict and evaluate possible impact on groundwater environment in periods of construction, operation and after the expiration of operation and service.Real and accurate first-hand original field data were obtained through the field investigation. HYDRUS software was used to simulate the groundwater pollutant migration law and characteristics of the thermal power plant and its ash field. The following conclusions are obtained:(1) Hydrogeological parameters of vadose zone of the power plant and ash area had been determined by environmental hydrogeology surveying and maping, filed geophysical prospecting, pitting, drilling and water seepage test.(2) Indoor hydrodynamic dispersion experiment results show that the dispersion coefficients of different kinds of soils in Wucaiwan area FMH, SH6 and SH1 is 936.9 cm2 ? h-1, 443.8 cm2 ?h-1, 119.1 cm2?h-1, respectively. The soil permeability of ash pile(FMH) and thermal power plant(SH6) are very poor, and both of them are good medium to pollution preventions. Ash field(SH1) is poorer in water permeability of soil, and is medium to pollution prevention, too.(3) Unsaturated water flow simulation software(HYDRUS-1D) was applied to simulate the leachate contaminant transport conditions of ash site area under these situations of precipitation once in a decade, hundred years and thousand years. The results showed that leaching filtrate of the ash field would have no impact on groundwater environment of ash field.(4) Unsaturated water flow simulation software(HYDRUS-1D) was used to simulate the contaminant transport conditions of the thermal power plant under the situations of wastewater continuous leaking. The results showed that after continuous sewage leakage for one day, ten days and 30 days, the maximum infiltration depth is 3.6, 8.7 and 14.2 meters, respectively, all pollutants of which didn’t reach the destination aquifer(confined aquifer)). After continuous sewage leakage for 100 days and 365 days, both pollutants of which can reach the confined aquifer, while the maximum concentration of the pollutants leakage is only 0.033 g/L and 1.7 g/ L, respectively(far less than salinity 102.9 g/ L of confined water in ZK4 well of the region).