剩余污泥基质生物滞留设施重金属环境风险评价

Environmental risk assessment of heavy metals in bioretention facility of excess sludge substrate

利用剩余污泥改良生物滞留设施基质可提升其雨水渗透及除污性能,但剩余污泥中重金属可能引发的潜在环境风险值得关注。分析了剩余污泥基质典型重金属的含量及赋存形态,采用3种评价方法分别对剩余污泥基质的重金属环境风险程度进行综合评价。结果表明,剩余污泥基质中Pb、Cr、As、Cu、Zn和Ni平均含量分别为16.11,85.36,13.06,24.65,218.69,17.78 mg/kg,Zn酸可提取态和可还原态含量较高,Pb、Cr、As、Cu和Ni残渣态含量较高;地累积指数法、内梅罗综合污染指数法和潜在生态风险指数法评价全部重金属均属安全水平或轻微生态危害。

The use of excess sludge modified bioretention facilities substrate can improve its performance of rainwater infiltration and pollutants removal,but the potential environmental risks of heavy metals in excess sludge are worthy of attention.The content and occurrence form of typical heavy metals in excess sludge substrate were analyzed,and three evaluation methods were used to comprehensively evaluate the heavy metal environmental risk of excess sludge substrate.The results showed that the average contents of Pb,Cr,As,Cu,Zn and Ni in the excess sludge substrate were 16.11,85.36,13.06,24.65,218.69,17.78 mg/kg respectively.The extractable and reducible contents of Zn acid were relatively high,and the residue contents of Pb,Cr,As,Cu and Ni were relatively high.All heavy metal elements were evaluated as safe level or slight ecological hazard by ground accumulation index method.Nemerow comprehensive pollution index method and potential ecological risk index method.