Study On Numerical Simulation And Control Measures Of Groundwater Pollution In Petrochemical Industry

With the development of the integration of Beijing-Tianjin-Hebei region,the industrial structure of Beijing has transferred and Tianjin Binhai New Zone which is abound of petroleum geologic reserves has become a petrochemical industrial base of North China.And it is also an important base for petroleum exploitation and utilization.In the process of petroleum exploitation and utilization,“Leakage”of the fuel has posed a serious threat to the groundwater.In this dissertation,the indoor and outdoor experiments were carried out for the process of groundwater pollution,and the laws and important parameters of the groundwater pollution were mastered.Based on the result,the model of the groundwater flow and the solute migration model of the groundwater in the study area were established,and the study of numerical simulation and prediction of the groundwater petroleum pollution and groundwater environmental capacity was carried out.At last,according to the results of the process of groundwater pollution and numerical simulation,the prevention measures were put forward.The vulnerability of silty clay and silty soil in the vadose zone were studied by static and dynamic experiments.In the static experiment,the adsorption isotherm model showed that the adsorption law of petroleum pollutants by silty clay and silty soil was more consistent with the Freundlich adsorption model.The adsorption kinetics test showed that the adsorption equilibrium time of petroleum pollutants by silty clay and silty soil was 24hours,and the saturated adsorption capacity was 10.8mg/kg and 4.7mg/kg,respectively.In dynamic experiment,the influence of rainfall leaching rate on adsorption performance through indoor soil column simulation.The results showed that the faster the leaching rate was,the less petroleum vadose zone soil would adsorb.The important parameters of the underground aquifer in the study were determined by the field pumping experiment and the determination of the porosity.The permeability coefficient of phreatic aquifer was from0.05 to 0.14m/d,and the porosity of muddy clay,silty clay and silty soil was 0.12,0.18,0.21,respectively.Based on the experimental research,the conceptual model of the groundwater system,the numerical model of the groundwater flow and the groundwater solute migration model were established,and the numerical simulation of the groundwater petroleum pollution in the study area was carried out,The results showed that the maximum exceeding standard distance of petroleum pollutants was 35.72m and the pollution range was 1678.15m² in the horizontal direction;the maximum pollution depth of petroleum pollutants was 11.25m in the vertical direction.The study on petroleum environmental capacity of groundwater showed that the maximum value was 10.9g/d,the minimum value was 1.2g/d.which provided scientific basis for the prevention of the groundwater petroleum pollutionBased on the simulation and prediction of the groundwater petroleum pollution and the results of the groundwater environmental capacity in the petroleum exploitation area,the permeability coefficient threshold of anti-seepage layer was 1.09×10^-12cm/s by inverse calculation in the petroleum exploitation area.Based on this,the anti-seepage layer structure of mud pool was determined,which was composed of filament non-woven geotextile,HDPE geomembrane,natural grit protective layer and surface pouring concrete.The main anti-seepage layer was HDPE geomembrane,its permeability coefficient was1.0×10^-13cm/s.And the rationality of economy and technology of the anti-seepage layer structure was analyzed.