开封县污水处理厂污泥资源化利用的潜在生态风险分析

摘要

In the present work ,the physico‐chemical properties and the contents of heavy metal elements ,such as Cu , Pb , Cr , As , Ni , Zn and Mn , etc ., in the sewage sludge from wastewater treatment plants in Kaifeng County were analyzed .The chemical states of these metals were investigated using BCR′s method ,and potential ecological risk index (RI) was used to evaluate the potential risk of these metals in sludge for agricultural use .The results showed that the physico‐chemical properties of sewage sludge met the requirement of Standards for Agricultural Use(CJ /T309‐2009) .All the heavy metals concentrations reached the require‐ment of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918‐2002) .However ,like Zn、Cu、Cr、As and Mn ,their contents were much higher than the background values of Kaifeng soils .In the sludge ,M n existed in mainly acid soluble and re‐duced forms ,Zn was in reduced states ,and Ni was distributed in five chemical forms ,Cu and Pb existed in metallo‐organic forms .The research assessed the sludge by single factor index , nemerow index method and index of geo‐accumulation belonged to serious contamination ,and the potential environmental comprehensive risk index of sludge is 48 9.2 ,w hich belonged to a low risk w hen applied in agriculture .%以开封县污水处理厂污泥为实验材料，分析了污泥基本理化性质和Cu、Pb、Cr、As、Ni、Zn、Mn等元素的含量，利用BCR提取法研究其存在形态特征，并利用潜在生态危害指数法（RI），对污泥中重金属农用可能带来的潜在风险进行了综合性评价．结果表明，污泥的基本理化性质满足C J／T 309‐2009农用泥质标准，污泥中所测元素含量均符合国家农用控制标准（GB 18918‐2002），但Zn、Cu、Cr、As、Mn含量高于开封市潮土背景值．污泥中M n主要以酸溶态和可还原态形式存在，Zn主要以可还原态形式存在，Ni在5种形态的分布差异不大，Cu、Pb主要以有机物结合态形式存在．单因子指数、内梅罗综合污染指数、地累积指数法对供试污泥样品的评价结果均为重污染水平，潜在生态危害指数489．2，属低风险水平．