原位钝化处理对污染底泥氮磷释放的影响

Study on In-situ Chemical Stability Restoration Technology of Contaminated Sediments

选取深圳茅洲河污染底泥为研究对象,以普通硅酸盐水泥作为钝化剂,研究原位钝化处理底泥释放厚度、钝化剂掺比及钝化层厚度等参数条件对污染底泥N,P释放规律的影响作用,并分析了原位钝化处理对污染底泥N,P释放的控制作用机理。结果表明:底泥中的污染层厚度会对上覆水中N,P水平产生持续影响,原位钝化处理是阻隔内源N,P污染物释放较为可行的有效途径;选择10%钝化剂掺入量和1 cm钝化层覆盖厚度对上覆水中N,P污染物削减较为经济有效;NH_(3)-N污染物的控制机理是以钝化层致密物理结构形成的物理屏障层阻隔了下层初始底泥中NH_(3)-N污染物向上覆水中的持续快速扩散,TP污染物的控制机理还包括了磷元素的赋存形态向磷酸氢盐或钙磷形态的转变。

The polluted sediment of the Maozhou River in Shenzhen was selected as the research object,and ordinary Portland cement was used as the passivating agent to study the effects of in-situ passivation treatment on the release thickness of the sediment,the ratio of passivation agent and the thickness of the passivation layer.The influence of the law of phosphorus release,and the control mechanism of the in-situ passivation treatment on the release of nitrogen and phosphorus from polluted sediments was analyzed.The results show that the thickness of the polluted layer in the bottom sludge will have a continuous effect on the level of nitrogen and phosphorus in the overlying water.In-situ passivation is a feasible and effective way to block the release of endogenous nitrogen and phosphorus pollutants;10%passivation agent is selected for mixing The amount of passivation layer and the thickness of 1 cm passivation layer are more economical and effective in reducing nitrogen and phosphorus pollutants in the overlying water;the control mechanism of ammonia nitrogen pollutants is that the physical barrier layer formed by the dense physical structure of the passivation layer blocks the ammonia nitrogen pollution in the lower initial sediment The continuous and rapid diffusion of substances in the overlying water,the control mechanism of total phosphorus pollutants also includes the conversion of the occurrence form of phosphorus to the form of hydrogen phosphate or calcium phosphorus.