Analysis for Gas Behaviors of the Groundwater Pollutant (Volatile Chlorinated Organic Compound) in Unsaturated Zone-for the Design of the Remediation Method by the Vacuum Extraction Technique-

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1.Characteristic of gaseous polluted material in porous medium : (1) In case of 1D column experiment, the characteristic of the vertical movement is depend on the diffusion in the porous medium. It is explained by using the diffusion coefficient in the air multiplied by the coefficient related to the porosity. (2) In case of 2D tank experiment, the expansion of the trichloroethylene gas in unsaturated zone is explained. The behavior in case of the solution is similar to one in case of the undiluted solution. And the proportional relation between concentration of the solution and one of the gas is made certain. (3) The 2D behavior of the volatile gas, when the vacuum extraction is carried out, is made clear. It depends on the value of the vacuum, and also on the surface boundary condition.2.Research of contaminated area : (1) The surface soil-gas survey in polluted area is effective for a soil and groundwater research in a shallow zone. (2) The remedial operation in the contaminated site is carried out. The removed rate of the pollutant at the initial stage of the operation is high. According to progress of the operation, its rate is decreased and the recovery rate by groundwater extraction is over the one by soil-gas extraction. (3) It is important to select the suitable remediational technique, according to the existing form of contaminant and to the progress of the recovery. The suitable standard to finish the operation and the method to evaluate the effect of the remedial operation are required.