摘要:本文通过现场采集及室内分析,研究了长三角洲地区南京、苏州、上海、杭州等7个城市的污水处理厂16份污泥样品中的四种重金属(Pb、Cd、 Cr、 Ni)。结果表明,不同污水处理厂的污泥样品中重金属元素的总量存在较大的差异,重金属Cd含量在0.3-11.1mg·kg-1之间,重金属Cr含量在468-6505mg·kg-1之间,重金属Ni含量在346-4309mg·kg-1之间,重金属Pb含量在1.9-9.9mg·kg-1之间,4种重金属元素平均含量的大小顺序为Cr(2771 mg·kg-1)> Ni(1846 mg·kg-1)> Cd(5.2 mg·kg-1)> Pb(5.1 mg·kg-1)。对各类污泥重金属污染指数比较表明,混流污水污泥为主的城市污泥中重金属污染程度明显高于生活污水为主污泥。为了保护生态环境和人类健康,防止二次污染,污泥土地利用时需考虑重金属含量,采取相应的控制措施。
关键词:重金属;城市污水污泥;资源化利用;长三角洲地区
Abstract:The heavy metal pollution became the biggest barrier to limit its large-scale land utilization. Sixteen sludge samples were collected from 7 cities such as Nanjing, Suzhou, Shanghai, Hangzhou and etc. Within Yangtze River Delta region, and the total contents of heavy metals (Pb, Cd, Cr, Ni) were investigated. The results showed that the contents of heavy metals in sludge samples varied significantly, the content of heavy metal Cr between 0.3and 11.1mg·kg-1, the content of heavy metal Cd between 468 and 6505mg·kg-1, the content of heavy metal Ni between 346 and 4309mg·kg-1, the content of heavy metal Pb between 1.9 and 9.9mg·kg-1, and the average contents of heavy metals exhibited an order of Cr(2771 mg·kg-1)>Ni(1846 mg·kg-1)>Cd(5.2 mg·kg-1)>Pb(5.1 mg·kg-1). Mixed flow sludge was more seriously polluted than domestic sludge according to pollutant indexes. Heavy metals content and measures should be considered to reduce potential risk to eco-environmental safety and public health upon land application of sewage sludge.
Key words: heavy metal ; city sewage sludge; resource utilization; Yangtze River Delta