Experimental Validation Of The 1,1,1-TCA Vapor Intrusion And The Recommended Vapor Model With A Scale Model

In the view of widely existed contaminated sites of chlorinated hydrocarbon,selecting the typical volatile chlorinated hydrocarbon(1,1,1-trichloroethane)as the main contaminate,a conceptual model of contaminated sites was established,and a physical model was built up to simulate the 1,1,1-trichlorothane vapor intrusion in vadose zone.Among the seven sensitive parameters analyzed by OAT method,the ratios of soil porosity and surface area gap were the highest,and the contents of soil organic carbon and soil moisture were relative least sensitive parameters.Through the collection,measurement and analysis of 1,1,1-trichlorothane gas,among the three factors of simulation analysis,the migration rate of 1,1,1-TCA vapor was the most affected by the soil porosity,and the initial pollution concentration was the second,and the contaminated source depth affected the migration rate of 1,1,1-TCA vapor invasion weak;when the depth of contaminate source was increased from 10 cm to 30 cm,the VF of the three porosity soils decreased by 15%,21%and 26%,when the soil porosity increased from 54.5%to 61.3%,the VF of the three different contaminate sources decreased by 22%,27%and 34%?The accuracy of numerical model is high,when the contaminated source was shallow and the soil porosity was large,and the inaccuracy of model results in the difference between the predicted result and the actual site,the calculated values of the three-phase equilibrium process and the model of migration and diffusion process were larger than the actual contaminated site.The ?sg actual values of A,B and C were 0.867,0.894 and 0.912,the larger the porosity was,the less accurate the model was,and the ratio of migration and attenuation coefficient ? were between 0.785 and 0.995,the deeper the contaminate source,the smaller the soil porosity,the lower the accuracy of the migration process model.