| The contaminated soil of enterprise moving in the city had been a challenge for engineering construction with the city development.The soil vapor extraction(SVE)is a common in-situ remediation technology for volatile organic compound(VOCs)in soil.However,the technology is affected by many geological environment variables,which lead SVE remediation effect is difficult to predict.The SVE remediation mechanism and effect can be studied and predicted by TMVOC model.However,the simulation by TMVOC needs a lot of geological and technological parameters,and it is difficult to predict the remediation effect.The accuracy of simulation results can be affected by lack of parameters.BTEX(Benzene,Toluene,Ethylbenzene,Xylene)was selected as the typical contaminations in the paper.The BTEX migration and transformation,and SVE remediation process in site scale was studied by laboratory test and numerical simulation.A quantitative evaluation model of SVE removal rate for BTEX contaminated site was established by comprehensively considered the site characteristic parameters and SVE process parameters.The model proposed a method for predicting SVE removal rate of BTEX contaminated sites,which provided technical guidance for SVE application.The research results were as follows:(1)The result of BTEX migration in vertical one-dimensional column was simulated by TMVOC model.The goodness of fit value of experiment and simulation results was 0.89 and 0.88,respectively.The model of BTEX migration and SVE remediation process of 15 sites was established by 15 typical petrochemical sites information.The BTEX distribution and SVE removal rates was predicted by the models.The effect of geological and SVE process parameters on BTEX migration and SVE removal rate was analyzed through pollution distribution and phase transformation.(2)Coupling with SVE removal rates simulation of 15 sites,laboratory test and correlation analysis results,11 influence factors of SVE removal rate was selected,include geological parameters of rainfall infiltration,groundwater depth,porosity,permeability,and pollution parameters of pollution depth,width,area,and SVE process parameters of extraction flow,influence radius,extraction well depth,number of extraction wells.The association degree((?))of SVE removal rate and 11 influence factors was analyzed by grey relational analysis method.6 influence factors,whose(?)greater than 0.75 was selected as main control factors.The 6 influence factors were unsaturated zone permeability(0.841),pollution area(0.838),groundwater depth(0.813),extraction flow(0.807),extraction well depth(0.796)and number of extraction wells(0.760).(3)The multiple linear regression equation of SVE removal rate and 6 main control factors was established.The equation considered the geological,contamination and SVE technological parameters.The SVE removal rate can be more quickly prediction with the equation than TMVOC.The established equation was satisfied the significance test and small error analysis,and it was verified by other representative sites.Therefore,the multiple linear regression equation of SVE removal rate and 6 main control factors can be used to predict SVE remediation effect. |
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