Study On The Migration And Transformation Of Oil-contaminants In Vadose Zone

With the development of modern industry, oil as an important energy and Industrial raw materials are widely used, but Oil will cause serious soil and groundwater pollution in mining, transportation, processing.Based on caofeidian region, This article select for petroleum contaminants as the research object, Through static adsorption experiments and microbial degradation experiments in data collection, analysis and study theory basis, which get natural related parameters, there are simulate the distribution characteristics of oil in vadose zone by mathematical model, and study transportation and transformation of oil in the vadose.By laboratory experiments and numerical simulation studies, research results are the following:(1) By batch adsorption test, the adsorption equilibrium time of four typical soil samples(Silt, sand silt, silt, silty clay) in 20℃in caofeidian is about 1h, the dynamic adsorption found Lagergren pseudo second order kinetic equation.(2) Oil adsorption isotherms of silt, silt and sand silt were fit to Langmuir adsorption model, The maximum adsorption capacity was 0.337mg/g,12.94mg/g,4.606mg/g. Because Silty clay has large adsorption capacity, resulting in a smaller range of equilibrium concentration, its adsorption isotherms were fit to linear models.(3) In this dissertation, According to the regional distribution of soil, as a typical silty sand medium, and a software HYDRUS-1D is utilized to simulate and forecast transportation and transformation of oil pollutants in the vadose.①In the case of Continuous pollution of vertical infiltration, oil Penetrate Vadose zone into groundwater in about 200d, that the Concentration reach Initial concentration.Pulse of pollution in the fixed head case, because contaminants are adsorbed and degradation, its concentration and decreases with depth.②Evaporation of rainfall conditions, Oil remaining in the surface of soil depth of 20～30cm through 10a, for the soil retards petroleum pollutants.The above study results, in the case of the high concentration of oil waste water infiltration in pressure situations, the greatest threat to groundwater in a short time to reach the ground, while in natural conditions, the oil is difficult to groundwater pollution.The research in this dissertation provides scientific support towards protection and utilization of Soil and underground water resources in delta of caofeidian.