我国重点流域城市污泥重金属含量与溯源研究

Heavy metals concentrations and their traceability in municipal sludge in major river basins of China

调研了我国重点流域106座典型污水处理厂污泥的重金属含量,并分析了重金属的可能来源。结果表明,污泥中不同重金属按照含量平均值大小排序依次为:总锌>总铜>总铬>总镍>总铅>总砷>总镉>总汞,其中总铬、总镍、总锌、总铜含量超过各项泥质标准限值的频率较高,总镉和总汞超过农用(A级)和土地改良/园林绿化(酸性土壤)标准限值的频率较高,总砷超标频率相对较低,所有样品中铅含量均满足标准要求。采矿、冶金和电镀行业是含重金属废水的主要来源,染料、制革、催化剂、电池、农药、机械加工等行业也会产生含重金属废水;此外,由工业废酸和废弃金属制备的混凝剂在工业废水预处理以及污泥脱水中应用较为普遍,是污泥中重金属的重要来源之一。

Heavy metals concentrations in the sludge of 106typical wastewater treatmentplants in China’s major river basins were investigated and their possible sources were analyzed.Theresults indicated that the average concentrations of heavy metals exhibited an order of Zn>Cu>Cr>Ni>Pb>As>Cd>Hg,while Cr,Ni,Zn,Cu showed high frequency of exceeding the limit setby each sludge standard,and Cd,Hg showed high frequency of exceeding the limits set by agricultural(class A)and land reclamation/landscaping(acidic soil)standards;the frequency that As exceeds sludge standard was relatively low,and Pb concentrations in all the samples were below thestandardlimits.Mining,metallurgy,electroplating industries were the main sources of thewastewater that content heavy metals,and dye,leather,catalyst,battery,pesticide,machineryprocessing and other industries also produced wastewater that content heavy metals.In addition,coagulants produced by industrial waste acid and waste metal were widely used in industrialwastewater pretreatment and sludge dewatering,which was one of the important sources of heavymetals in sludge.