河流泥沙对污染河水中污染物的吸附特性研究

Adsorption properties of sediment to pollutants of contaminated river water

泥沙是河流水体的重要组成部分,在迁移过程中吸附一定的氮、磷进入底层或下游,从而改变水中污染物的分布。通过模拟试验,选择粒径76μm以下泥沙研究不同泥沙含量、不同污染程度等条件下,河流泥沙对污染河水中氮、磷等污染物的吸附特性。结果表明:河流泥沙对污染河水的氮、磷及高锰酸盐指数均有一定的吸附效果,特别是对氮、磷的等温吸附比较明显;与对照相比,含泥沙的试验组水体磷质量浓度最大降低值达0.53mg·L-1;水体溶解性总氮随时间延长,含量逐渐下降。污染物含量、泥沙含量、粒径等均会影响泥沙对污染物的吸附,污染物含量越高、泥沙含量越大、粒径越小吸附效果相对越好。泥沙吸附和富集污染物后沉降进入水体底层,离开水相,因而可以降低水中污染物含量,达到净化水质的作用。

Sediment is the important component of river water. It can absorb pollutants from water and deposit to the water bottom or move to the lower reaches of river. Some simulated experiments were conducted to study the influence of sediment characteristic and pollutant concentration on pollutant absorption properties by sediment of below 76 μm from contaminated fiver water. The results indicate that the sediment could adsorb nitrogen, phosphorus and CODMn contamination quite well. Comparing with control test, no additional sediment, total phosphorus concentration of contaminated river water decreased furthest by 0.53 mg·L^-1 in the experimental system with additional sediment. The concentration of DTN was decreased gradually. Some factors, such as concentrations of pollutants and sediment, particle size of sediment, had great influence on adsorption properties. The higher the concentrations of pollutants and sediment were, the higher the absorption efficiency would be. The particle size of sediment had active influence on the absorption efficiency. Sediment absorbed and accumulated pollutants from water then deposited into the water bottom. This would be an important process of self-purification in the water with sediment.