汞污染土壤淋洗修复工程应用分析

Analysis on the Application of Heavy Metal Mercury Contaminated Soil Leaching Remediation Engineering

以上海市某汞污染土壤淋洗修复项目工程实例为研究对象,根据前期环境调查评估及方案,确认地块土壤中Hg的最高质量分数为37.9mg/kg,修复目标值为8mg/kg,最大超标倍数为3.74倍,修复方量为776.52m^(3)。通过修复技术选择、粒径实验分析、现场中试等过程确定淋洗修复的工艺参数:淋洗固液比为1:5,泥浆停留总时间为30min,淋洗剂采用EDTA(乙二胺四乙酸二钠)和柠檬酸复配药剂,淋洗剂质量分数为0.02%。结合修复工程的实施过程,重点介绍了污染土壤预处理、淋洗修复、淋洗废水处理、土壤修复效果评估等关键过程,综合分析淋洗修复存在的问题和建议,以期为其它重金属污染壤修复提供参考。

Taking an example of a heavy metal mercury contaminated soil leaching and restoration project in Shanghai as the research object,based on the preliminary environmental investigation assessment and plan,it was confirmed that the maximum pollution concentration of mercury in the soil of the plot is 37.9 mg/kg,and the restoration target value is 8 mg/kg,the maximum exceedance multiple is 3.74 times,and the repair volume is 776.52 m^(3).The process parameters of leaching repair were determined through repair technology selection,particle size experimental analysis,on-site pilot testing and other processes.The leaching solid-liquid ratio was 1:5,the total mud residence time was 30 minutes,and EDTA(ethylenediamine)was used as the eluent.Disodium tetraacetate and citric acid compound agent,the mass ratio of eluent is 0.02%.Combined with the implementation process of the remediation project,the key processes such as contaminated soil pretreatment,leaching remediation,leaching wastewater treatment,and soil remediation effect assessment are highlighted,and the existing problems and suggestions for leaching remediation are comprehensively analyzed,with a view to providing information for the remediation of other heavy metal-contaminated soils.