污水污泥中重金属污染物的溶出过程研究

污水污泥中污染物尤其是重金属的水体浸出作为重要的二次污染途径备受关注。为了探讨污水污泥中重金属的溶出规律,对上海7个污水处理厂的污水污泥进行了重金属总量分析,并采用水平振荡法对上述污水污泥中重金属进行了溶出动力学研究。结果表明,污水污泥中Cu、Cr和Zn的含量均较高,之后依次是Pb、As、Cd和Hg;污水污泥中重金属溶出动力学过程分为快速反应和慢速反应两个过程,可以用Elovich方程进行模拟;污水污泥中各重金属的溶出负荷差异较大,Cu、Cr和Zn的溶出负荷较大,其他较小,但各重金属相对于污水污泥中重金属总量的溶出百分比差异不大,基本处于10%以下。

Study on dissolution processes of heavy metals from sewage sludge

As one of the important secondary pollution pathway, the leaching process of heavy metals from sewage sludge has gained increasing attention. To explore the heavy metals dissolution from sewage sludge, the total amount of heavy metals in 7 sludge samples from Shanghai were analyzed, and the dissolution kinetics of heavy metals from sewage sludge were also conducted using horizontal vibration procedure to explore the leaching characteristics. The result indicated that the contents of Cu, Cr and Zn were relatively high in sewage sludge, followed by Pb, As, Cd and Hg. The dissolution kinetics of heavy metals from sewage sludge was a biphasic process-the quick phase and the later slow phase, and can be described with Elovich equation. The difference of dissolution load of heavy metals in different sewage sludge was significant. Cu, Cr and Zn were relatively high, and the others were low, however, the difference of dissolution percentage, that was the ratio of dissolution load and total amount of heavy metals in sewage sludge, was small and normally less than 10%.