原位水平阻隔风险管控技术在某退役工业污染场地治理中的应用

Application of in-situ horizontal barrier risk control technology in the treatment of a decommissioned industrial contaminated site

为满足人体健康风险管控目标,结合某退役工业污染场地后期开发工作情景,分别针对室内外区域设计了针对性的风险管控方案。室内区域建筑物地基下方−2 m污染土采用土壤气阻隔控制工程,在建筑物地基底板与导气层之间喷涂隔气膜对土壤气进行阻隔,控制建筑物下方导气层负压为−5~−2 Pa,利用抽提系统对土壤气进行集中收集,经尾气处理系统处理达标排放;室外区域原始地面标高−3 m以下污染土采用HDPE膜(两布一膜)进行水平阻隔,阻隔层上方采用清洁黏土覆盖压实。工程设施完工1年内开展的风险管控效果评估结果表明,室内外区域风险管控工程的工程性能指标及污染物指标均符合评估标准要求,达到预期效果,工程已于2021年12月通过生态环境主管部门验收,进入后期环境监管。

In order to meet the goal of human health risk control,targeted risk control schemes were designed for indoor and outdoor areas in combination with the working situation of later site development scenarios of a decommissioned industrial contaminated site.For the−2 m contaminated soil under the foundation of indoor regional buildings,the soil gas barrier control project was adopted.The soil gas was blocked by spraying a film between the foundation and the air guide layer of the building,and the negative pressure of the air guide layer below the building was controlled to be−5-−2 Pa.The soil gas was collected by the extraction system,which was treated by the tail gas treatment system to reach the standard before discharge.HDPE film(two cloth and one film)was used as a horizontal barrier for contaminated soil with an original ground elevation below−3 m in outdoor areas,and clean clay was used for cover and compaction above the barrier layer.The results of the risk control effectiveness evaluation carried out within one year after project completion showed that the engineering performance indicators and pollutant indicators of the indoor and outdoor areas met the evaluation standards and achieved the expected effect.The project passed the acceptance of the ecological environment department in December 2021 and entered the later stage of environmental supervision.