Study Of Migration Behavior Of Chlorinated Hydrocarbons In Unsaturated Zone From Leachate

Chlorinated Hydrocarbon is very harmful organic pollutants that is bad for human health and the environment. With the accelerated process of industrialization, waste contains Chlorinated Hydrocarbon is increasing, so the leachate have more chlorinated hydrocarbon in it. In some Garbage Heap which anti-seepage measure is crude or lacks anti-seepage measure, the Garbage Heap in rural area specially. the seeping of leachate in this area will cause the environment of soil and groundwater be polluted by Chlorinated Hydrocarbons which is in leachate.In this paper we made a simply equipped Garbage Heap in Chengdu as the research object, selected Pentachlorobibenzene and Hexachlorobenzene as the characteristic pollutants in leachate through the study of the characteristics of the soil in regional Unsaturated Zone and leachate in this Garbage Heap. Ascertained Kd the distribution coefficients and DZZ the vertical diffusion coefficients of the two characteristic pollutants through soil column experiment based on leaching by leachate and Dispersion experiment. Established the migration model in the Unsaturated Zone of Pentachlorobibenzene and Hexachlorobenzene. Predicted the time that the two characteristic pollutants penetrate through the Unsaturated Zone into groundwater.The isothermal adsorption of Pentachlorobibenzene and Hexachlorobenzene conform to Linear equilibrium isothermal adsorption; The distribution coefficients of Pentachlorobibenzene Kd1=0.097L/g, The distribution coefficients of Hexachlorobenzene Kd2=0.137L/g; Kd1< Kd2,so Hexachlorobenzene stay in the regional Unsaturated Zone more easily than Pentachlorobibenzene and Pentachlorobibenzene penetrate through the Unsaturated Zone into groundwater more easily than Hexachlorobenzene. So Pentachlorobibenzene pollutants the groundwater more easily than Hexachlorobenzene in the regional Unsaturated Zone; The maximum adsorption capacity of the soil in regional Unsaturated Zone to Pentachlorobibenzene and Hexachlorobenzene are Sm1=6319mg/g, Sm2=17182mg/g, so when the adsorption capacity of the soil in regional Unsaturated Zone run up to maximum, the adsorption capacity to Hexachlorobenzene is nearly three times the adsorption capacity to Pentachlorobibenzene.The adsorption capacity of Hexachlorobenzene is better than that of Pentachlorobibenzene in regional Unsaturated Zone.Under the condition of the same time, concentration of Hexachlorobenzene and Pentachlorobibenzene in the leachate decreases with increasing depth of the Unsaturated Zone, that indicating the Unsaturated Zone can adsorpt and delay the vertical migration process of the two kinds of Typicalchlorinated Hydrocarbons,more thicker the Unsaturated Zone is more longer time the two kinds of Typicalchlorinated Hydrocarbons penetration the Unsaturated Zone into groundwater need; Under the same depth, with the increase of time, concentration of Hexachlorobenzene and Pentachlorobibenzene in the leachate are increasing and gradually reached its initial concentration, the Unsaturated Zone is to be saturated; The time of Hexachlorobenzene and Pentachlorobibenzene penetration the Unsaturated Zone are 1670d、2505d, and when in 10000d the the adsorption capacity of the soil in regional Unsaturated Zone to Hexachlorobenzene and Pentachlorobibenzene reach to Saturation, the vertical migration of the two characteristic pollutants do not be effected by the Unsaturated Zone, They will enter the groundwater with initial concentration, then pollution of groundwater environment.This research is good for ascertaining the concentration of pollutant which is from land surface going through the Unsaturated Zone into groundwater, it can provide the theoretical basis for prevention and treatment pollution of the soil and groundwater in the Garbage Heap area.