污染场地固化/稳定化修复的评价方法与标准

摘要

固化/稳定化技术是一项在欧美等国家的污染场地修复中广泛应用的技术.在分析固化/稳定化修复效果常用的浸出试验方法和物理评价方法以及相对应的评价标准的基础上,发现我国固化/稳定化修复效果的评价方法仅有少量振荡浸出试验的方法,还缺少动态浸出试验的评价方法;浸出毒性测试普遍采用硫酸硝酸法浸出评估,忽略了As、Cr(Ⅵ)等含氧阴离子在中性至弱碱性pH下溶解度达到最大的情况;固化/稳定化修复效果的评价标准则主要借鉴固废毒性鉴别与管理方法,但该方法未规定污染土壤资源化再利用时的评价依据;另外,污染土壤和固体废物的自身特性也有一定的差异.提出了基于我国国情的污染土壤固化/稳定化浸出测试和评价标准体系:当污染土壤固化/稳定化后采用卫生填埋或一般工业固体废物贮存、处置场处置时,可参考固体废物填埋处置时的评价方法与标准;当污染土壤固化/稳定化后原址填埋时,则应增加绕流浸出方法或穿透浸出试验方法,其评价标准可参考GB/T 14848-1993《地下水质量标准》或根据关注点浓度的要求进行风险评估推算确定;当污染土壤固化/稳定化后再利用时,需根据再利用的具体情景选择相应的评价方法与标准.%Solidification/stabilization (S/S) is a widely used treatment technique to remediate contaminated sites in the EU and the United States.Test methods for the assessment of S/S materials,including leachability and physical tests,were reviewed.The performance criteria for the assessment of S/S materials was also summarized.In China,only a few agitated extraction tests and no dynamic tests are used for evaluating the effectiveness of S/S.Among these tests,the sulphuric acid & nitric acid method is the most frequently used,without considering that the leachability of oxyanions,such as As and Cr(Ⅵ),is higher at neutral or weak basic pH.The performance criteria for the assessment of S/S materials is mainly based on identification and management method for solid waste;however,the method doesn't include the strategy of reuse of contaminated soils.Besides,the characteristics of contaminated soils are different with solid wastes.The system of testing and performance criteria for the assessment of S/S materials was developed based on China's national conditions.Related standards of waste solid can be used as a reference,when S/S materials are sanitary landfilled or stored and disposed as general industrial solid wastes.Flow-around tests or flow-through tests should be considered when S/S materials are buried on site;the performance criteria can refer to Quality Standard for Ground Water GB/T 14848-1993 or requirement specified at the point of compliance.When S/S materials are reused,testing and performance criteria should be determined based on site-specific requirements.