Pollution Migration Law Of Aeration Zone And Groundwater In The Eastern Part Of Zhengzhou Airport Area

The rapid development of urban construction brought different degree of urban waterlogging problems,has seriously affected the economic development of zhengzhou airport is the design of the first national airport experimental zone,sponge urban construction will be sent to you by rainwater collection and make a rainwater to use more reasonable,but the sponge in the process of urban construction,collection rain in all parts of the pollutant concentration,can be directly affect the location of the soil and groundwater quality,this paper mainly combines the sponge city construction projects,airports are filled soil characteristics and pollutant migration regularity in vadose zone and underground water.In this paper,the characteristics of soil and adsorption law of the study area were first studied,and on this basis,indoor soil column experiment was designed to analyze the transport law of soil pollutants in the aerated zone.Finally,a numerical simulation model of groundwater is established to analyze and predict the transport law and trend of groundwater pollutants in the region of cavernous body.The results of soil sample adsorption kinetics and isothermal adsorption experiments showed that the dynamic adsorption of ammonia nitrogen in soil sample points was completed instantaneously,and the instantaneous adsorption amount reached more than 85% of the total amount,and then slowed down.Isothermal adsorption curve to show the solution concentration and adsorption capacity of nonlinear soil particles changes,changes in the early stage of the adsorption quantity quickly,late slow,adsorption rate and adsorption from early to late slow iron ion adsorption process and similarity to ammonia nitrogen adsorption dynamic adsorption results shows that the ammonia nitrogen adsorption from the soil sample was a stable in 240ug/g,soil samples were 300ug/g;The adsorption capacity of iron ion in soil sample 1 was stable at 220ug/g,and that in soil sample 2 was 140ug/g.The relevant isothermal fitting adsorption parameters R2 obtained in the adsorption thermodynamics experiments of the two soil samples were all above 0.98.The adsorption capacity of ammonia nitrogen in soil sample 1 was 714.29ug/g,and that in soil sample 2 was 833.33ug/g.The analysis and calculation results of soil column tracer experiment data show that the dispersion of soil sample 1 is 1.057 cm and that of soil sample 2 is 0.845 cm.According to the experimental data of ammonia nitrogen and iron ion,the migration process can be divided into two parts.The second part is the region tending to stability,during which the increase rate of solution concentration gradually slows down and gradually reaches a stable state in the later period.The vadose zone thickness in the study area are between 20-30 m,20 m vadose zone thickness,because of the ammonia nitrogen migration and iron ion migration are approximate to linear migration instantaneous adsorption,without considering the lateral migration under the condition of adsorption,by experiment,20 cm soil column adsorption saturation to 400 h,completely is 20 m vadose zone thickness adsorption saturation is about 40000 h,or about five years.Through the generalization of aquifer,boundary conditions and main parameters of aquifer in the research area,the hydrogeological model of the research area was constructed.Visual MODFLOW software was used as the research platform,and finite difference method was adopted to solve the problem.The design of a total of two programs,1 year,5 years of infiltration.According to the test of existing surface water quality,ammonia nitrogen concentration is 4.6mg/L and iron ion concentration is 0.546mg/L.According to the simulation results,with the extension of simulation time,the diffusion area of ammonia nitrogen is further expanded,and the diffusion area and distance in the east and south are larger,while the diffusion distance and area in other directions are smaller.The diffusion distance is about 500 m,the diffusion distance in the south is about 400-500 m,and the diffusion distance in the north and west ranges from 300-350 m.The water level in the vicinity of the central park reached 120 m,the water level in other places rose faster,and the change area of underground water level further increased,the affected area reached 1500 m transverse distance and 1400 m longitudinal distance,and the affected area increased.