某地块铅、砷污染土壤固化/稳定化、异位淋洗修复技术研究

Study on Solidification/Stabilization and Ex-situ Soil Washing Remediation Technology of Lead and Arsenic Contaminated Soil in A Certain Plot

以广州市某地块铅、砷污染土壤为对象,通过小试或中试探讨污染物浓度、土壤粒径等因素对固化/稳定化和异位淋洗效果的影响。研究结果表明,1%磷酸三钠+2%水泥异位、原位固化/稳定化效果更好,均可使不同浓度铅、砷污染土壤浸出浓度达到地下水IV类标准;对于中低浓度的铅、砷污染土壤,采用水作为淋洗剂,异位淋洗可使粒径≥0.15 mm土壤达到第二类建设用地筛选值的目标,土壤减量化约60%。因此,异位和原位固化/稳定化、异位淋洗对本地块铅、砷污染土壤修复均具有良好的适用性,对典型铅、砷污染场地的修复工作具有一定的指导意义。

Taking the lead and arsenic contaminated soil in a plot of land in Guangzhou as the object,the effects of pollutant concentration and soil particle size on solidification/stabilization and ex-situ soil washing were investigated through small-scale or pilot tests.The results show that 1%trisodium phosphate+2%cement has better ex-situ and in-situ solidification/stabilization effects,which can make the leaching concentration of different concentrations of lead and arsenic contaminated soil reach the standard of groundwater class IV,and for medium and low concentration of lead and arsenic contaminated soil,using water as the eluent,ex-situ soil washing can make the soil with a particle size≥0.15 mm meet the target of the risk screening values for soil contamination of development land,and the soil reduction is about 60%.Therefore,ex-situ and in-situ solidification/stabilization and ex-situ soil washing have good applicability to the remediation of lead and arsenic contaminated soils,and have certain guiding significance for the remediation of typical lead and arsenic-contaminated sites.