采用ICP-MS分析法测定了我国3个典型沿海城市广州、上海和大连共13个污水处理厂污泥的7种重金属含量,并与2006年和2001年的数据进行了对比,以了解我国沿海城市污水处理厂重金属污染状况、变化趋势和处置方案.结果表明,我国沿海城市污泥中重金属污染分布存在较大差异,7种重金属平均含量大小顺序为Cr〉Zn〉Cu〉Pb〉As〉Hg〉Cd,Cr、Cu和As的含量超出了《城镇污水处理厂污染物排放标准》,污染严重.相对于以前,我国沿海城市污泥中Zn的含量明显减少,Pb、Hg和Cd的含量与没有明显变化,但Cr、Cu、As均明显增加.各区域各类型污水处理厂城市污泥重金属含量分析表明,来源于工业废水的城市污泥中Zn、Cu和Hg的平均含量较生活污水为主的污泥高;广州污水处理厂城市污泥中Cr、Pb、As、Hg和Cd的含量均高于上海和大连.沿海城市污水处理厂中超出《城镇污水处理厂污染物排放标准》中污泥农用标准限值的占总调查污水处理厂的23%,我国沿海城市污泥大部分仍可采用污泥农用的有益处置方式进行处置.同时,本次调查数据也为我国沿海城市开展污水污泥海洋倾倒相关技术标准的制定提供了基础数据.
Thirteen sludge samples from Guangzhou,Shanghai and Dalian were collected and analysed for heavy metals to investigate the distribution and variation trend of heavy metals in sludge from wastewater treatment plants in Chinese coastal areas.The results showed that contents of heavy metals in sludge varied significantly,and the average contents exhibited an order of CrZnCuPbAsHgCd.Additionally,contents of Cr,Cu and As exceeded their corresponding standard levels.Compared with contents of heavy metals in 2006 and 2001,content of Zn in sludge increased while contents of Cr,Cu and As decreased.Results also indicated that the industrial sludge was more seriously polluted than domestic sludge in terms of Zn,Cu and As.Only 23% sludge samples exceeded the standards for fertilization of sludge,suggesting that most of the sludge could be disposed by land application.These results also provide further information about the establishment of ocean disposal assessment for sludge.