Study On The Contaminant Migration In The Layered Heterogeneous Aquifers During The Pollution And Hydrodynamics Remediation Process

The heterogeneous formation of underground environment plays a decisive role in solute transport process.Low permeability media have greatly reduced the effectiveness of pump and treat and air sparging,in situ chemical oxidation and in situ biodegradation,resulting in poor repair result,even the smearing effect and rebound effect.Therefore,low permeability formation,non pollutant migration rules in homogeneous formation has become the focus and key research.In this paper,the image simulation of tank flow field by the method of nondestructive analysis,using layered heterogeneous aquifer as the research object,selects an inert tracer edible blue represents a miscible,non reactive pollutants in heterogeneous aquifer pollution and water power repair related simulation experiment.The experiment set different groundwater velocity and permeability difference,to explore the different conditions of low permeability medium pollutant migration and distribution,and Matlab programming based on quantitative calculation of enrichment and removal process of simulated pollutants pollution and water quality in the tank power repair process,in order to understand the pollutants in heterogeneous water Provide the basis for the migration process in the layer.This paper constructs the analysis method based on the Matlab image extraction precision and accuracy of the pollution plume depict two aspects compared with the traditional sampling method from the concentration information,verify the accuracy of the image analysis method,and the simulation of pollutants on the tank storage quality is quantitatively calculated by using the relevant procedures.The results show that the monitoring precision and plume accuracy can be raised by one order of magnitude and 2.9%respectively when we use the image processing method rather than the sampling method.If the porous media is non-honogeneous like this study,plume accuracy can be raised by 17.4%significantly.We can get the storage mass exactly using the Matlab program.When the grid number is 3700~2,the minimum error is 0.6%.Generally,image processing method provides a high-accuracy and high-resolution way to acquire and dispose the picture which can describe the migration process in the heterogeneous media more subtly.In the experiment of layered pollution in heterogeneous aquifers,groundwater flow velocity increases with penetration to pollutant high permeability,but will reduce the peak value of the breakthrough curve.The migration process of pollutants molecules are not in low permeability formation caused only by the concentration gradient diffusion caused by the change of high permeability zone hydrodynamic conditions have important effects on solute transport in low permeability formation.Increase the high permeability velocity of groundwater in formation will not only make the pollutant migration distance in low permeability formation in growth,will lead to accumulation of pollutants in the quality of the increase in the low permeability formation.From the perspective of differential permeability permeability,the greater the difference,is not conducive to pollutant migration to low permeability formation in.In the hydrodynamic experiment of layered restoration in heterogeneous aquifers,there are obvious smearing effect of high permeability strata penetration curve.The greater the difference of permeability,the smearing effect is more obvious.The pollutant removal in low permeability formation may also be affected by high permeability zone water power,a simple molecular reverse diffusion mechanism is not suitable for layered aquifer pollutants release process.The mass transfer in the upper and lower porous media show asymmetry.The mass transfer in upper media are faster than the one ower porous media during the pollution and repair process.