大型溞-沉水植物组合系统去除北京沙河水库水与底泥污染物效果研究

针对北京市沙河水库目前水体自净能力弱、水质较差等问题，研究以大型溞-沉水植物组合系统为核心的库区水体与底泥净化方法.通过前期投放大型溞提高水体透明度为沉水植物生长提供先决条件，然后利用3种沉水植物（即金鱼藻、狐尾藻和黑藻=1：1：1）去除湖库污染水体中污染物，本文重点考察在不同种植密度下组合系统对沙河水库水体、底泥污染物的去除效果.研究结果表明：在种植密度分别为30%和50%时，3种植物均长势良好，而在种植密度为80%时，金鱼藻和狐尾藻生长受到胁迫，但黑藻仍能继续增长，表现出较好的耐受性；当沉水植物种植密度为50%时，各污染物去除效果较好，系统稳定后COD、TN、NH₄⁺-N、NO₃^--N和TP的去除率分别可达45.4%、42.8%、66.0%、46.4%和85.9%.底泥有机质、总氮和总磷的去除率分别达到15.8%、33.3%和19.6%.

Study on the efficiencies of removing pollutants from water and sediment of Shahe Reservoir in Beijing by Daphnia magna-submerged macrophytes system

To solve the problems of weak self-purification capacity and poor water quality of Shahe Reservoir in Beijing, Daphnia magna-submerged macrophytes combination system has been developed for purification of water body and sediment in the reservoir area. In the developed system, the added Daphnia Magna enhanced the transparency of water body, providing the precondition for the growth of submerged macrophytes. Then three submerged macrophytes (Ceratophyllum Demersum, Myriophyllum verticillatum and Hydrilla Verticillata=1:1:1) were planted at different planting densities with proportion of 1:1:1. This paper studied the effect of planting density of submerged plants on the removal efficiencies of water and sediment pollutants in Shahe reservoir by the combined system. The results showed that when the planting density was 30% and 50%, the three plants grew well, while when the planting density was 80%, the growth of Ceratophyllum Demersum, and Myriophyllum verticillatum were stressed, but the Hydrilla verticillata could continue to grow, showing good tolerance. When the coverage of submerged macrophytes was 50%, the combined system had the best removal efficiency of COD, TN, NH₄⁺-N, NO₃^--N and TP, which were 45.4%, 42.8%, 66.0%, 46.4% and 85.9%, respectively. The removal efficiencies of organic content, total nitrogen and total phosphorus in the sediment were 15.8%, 33.3% and 19.6%, respectively.