透水坝原位净化山溪性污染河流

In-situ remediation of polluted hilly river with permeable dams

针对苕溪流域山溪性河流锦溪水质污染的现状,结合河流水文特征在河道内建设了三级透水坝,考察其对河流水质原位净化的效果。结果表明,透水坝有利于减缓山溪性河流的水速,对水流所携带的悬浮颗粒进行拦截、沉降,对河水浊度的平均去除率约为25%,并可将河水溶解氧(DO)提高1 mg/L以上。透水坝对河流水质的净化效果呈现明显的季节波动,夏季对COD、NH3-N、TN和TP的去除率最高,可维持在20%以上。秋季污染物去除效果有所下降,可能是由于水体中硝化-反硝化菌活性降低、水生植物同化吸收能力有限造成。将来可在透水坝壅水区内优化搭配种植挺水与沉水植物,改善其对氮磷的去除效果。

Concerning the current pollution status of the hilly Jinxi River located in Tiaoxi Basin,this study constructed tri-level permeable dams in the riverway based on the hydrological characteristics and evaluated their in-situ remediation performance. The results show that the permeable dams could reduce the water velocity so as to intercept and precipitate the suspended solids carried by water flow. On average,the turbidity removal reached about 25% and the dissolved oxygen concentration increased by 1 mg /L. The remediation performance exhibited significant seasonal variations,with the maximum removals of COD,NH3-N,TN and TP obtained in summer( i. e.> 20%). Probably due to the lower activities of bacterial nitrification-denitrification and aquatic plant assimilation,the removal of pollutants decreased in autumn. To improve the removal of nitrogen and phosphorus,it is suggested that emerged and submerged macrophytes be grown through optimal collocation in the backwater area of the permeable dams.