市政污泥中重金属赋存状态及生物有效性

Study on occurrence state and bioavailability of heavy metals in municipal sludge

在分析污泥理化性质的基础上,采用Tessier连续提取法对污泥中的Cu、Zn、Pb、Ni、Cd、Cr进行形态及生物有效性分析.结果表明,该污泥中有机质含量达到45.62%,N、P、K含量分别为1.55%、4.26%、1.01%,重金属含量均低于污泥农用控制标准值.污泥中Cu的生物有效态占2.65%,潜在有效态占36.52%,不可利用态占60.83%;Zn的生物有效态占1.24%,潜在有效态占10.71%,不可利用态占88.05%;Pb全部以残渣态存在于污泥中,不可利用态占100%;Ni的生物有效态占46.01%,不可利用态占53.99%;该污泥中未检测出Cd和Cr.污泥中重金属主要以非交换态形式存在,生物可利用程度低,对污泥堆肥农用非常有利.

On the basis of analyzing the physical and chemical properties of sludge, the selective sequential extraction procedures developed by Tessier was used to study the chemical forms and the bioavailability of heavy metals （ Cu, Zn, Pb, Ni, Cd and Cr） in municipal sludge. The experimental result indicated that the content of organic matter in the sludge reached 45.62 % ,the contents of N, P and K were 1.55 % , 4.26 % and 1.01 %, respectively, and the contents of heavy metals were lower than those of the control standard of sludge. The proportions of effective forms of Cu, Zn and Ni were 2.65 %, 1.24 % and 46.01 % respectively. The potential effective forms of Cu and Zn were 36.52 % and 10.71%, respectively, and theunavailable forms of Cu, Zn, Pb and Ni were 60.83 %, 88.05 %, 100 % and 53.99 %, respectively.Metals Cd and Cr were not detected in the sludge. The heavy metals mainly exist in the forms of non-exchange state, and the bioavailability is low, which is very beneficial to the use of composting processin agriculture.