河道底泥重金属浸出毒性分析及其固化/稳定化效果

城市内河由于长期承纳污染物导致其底泥受到污染,特别是其中重金属污染严重。选取某城市纳污河淤泥为试验对象,发现底泥Cr、Cu、Ni和Zn含量和浸出浓度均较高。为使其达到资源再利用要求,研究了一种污泥改性剂对其固化/稳定化的效果。结果显示,当改性剂掺量为10%时,已能够显著提高淤泥各个龄期强度。固化淤泥重金属浸出浓度在7 d时已明显降低,且随养护时间增长进一步降低。改性剂掺量为13%时,固化淤泥Cu、Ni和Zn浸出浓度可降低90%以上,而Cr浸出浓度也可降低80%左右。实验表明,污泥改性剂处理后淤泥抗压强度提高,同时有害物质得到有效的稳定。

Heavy metal leaching concentration and solidification/stabilization of river sediment

The river has received pollutants for a long time,especially for heavy metals.It is expected to result in sediment pollution.Three samples of sediment from an urban river were studied to investigate the heavy metals pollution.The results demonstrate that the content and leaching concentration of Cr、Cu、Ni、Zn in the sediment are high.Thus,in order to meet the requirement of contaminated sediment reutilization,a sludge modification agent was used for treating the sediment.Results show that the unconfined compressive strength of materials is able to significantly improve at each curing period,when the modifier ratio is 10%.Meanwhile,leaching concentrations of heavy metals decrease obviously after 7 days curing,and reduce further with the increase of curing time.After addition of 13% modifier,the concentrations of Cu,Ni,Zn are reduced by more than 90%,and the concentration of Cr is reduced by about 80%.Experiment indicates that the treated sediment has more compressive strength,and harmful substances are stabilized effectively.