Sand Column Experiment And Sand Tough Simulation Of Remediation Of Trichloroethylene Contaminated Groundwater By Micro Zero Valent Iron

Trichloroethylene(TCE)pollution is a kind of groundwater pollutant which is more common and difficult to degrade.Relevant research and practice have proved that nano zero valent iron(NZVI)has a good remediation effect on TCE.However,NZVI is not the best remediation material in practical engineering application.The removal efficiency of micro zero valent iron(MZVI)is slightly lower than that of NZVI,but it has no agglomeration effect and low price,so MZVI can be used as a substitute material.In this study,through the construction of TCE contaminated sand column and sandtough simulation remediation experiments,combined with MZVI migration experiment,the remediation effect of MZVI particles on TCE pollution and its migration law in sand body were comprehensively discussed.The main research results are as follows:(1)As a TCE pollution remediation material,MZVI is economical and practical,the unit price is only one fifth of NZVI,and the removal rate of TCE pollution in pore water of sand column is faster and the effect is better,in about 60 days,the pore water of sand column can be recovered to 10~2μg/L of TCE,which is close to the third grade of groundwater quality standard.The results show that TCE can be affected by changing the mesh number and dosage of MZVI and the particle size of experimental medium.The exponential function statistical model can describe the change of TCE concentration in the remediation process.The change of water environment caused by reduction remediation process is mainly reflected in the rapid change of redox potential from oxidation state to reduction state and the increase of the total number of colonies in water.(2)The migration of the iron in the MZVI system shows that the number of iron and the amount of the added iron are positively related to their vertical migration ability.The high head difference and large diameter can show a strong horizontal migration ability.The vertical and horizontal migration ability can be improved by increasing the particle size of sand.(3)The results of sandbox restoration experiments show that the removal efficiency of sandbox at different points is significantly different.The reduction of hydraulic gradient will lead to the increase of upstream reaction rate and the decrease of downstream reaction rate.The change of hydrochemical environment caused by the remediation process is mainly reflected in the slow decline of sand from oxidation environment to reduction environment,and the overall p H value shows a slight upward trend.In this paper,the prospect of MZVI in the remediation of soil and groundwater pollution is revealed,which can be used for reference in the treatment of soil and groundwater TCE pollution.There are fouty pictures,seventeen tables and fifty-two references in this thesis.