多元组合系统净化富营养化水体的示范工程

杭州西湖上游龙泓涧受到周边茶园面源污染，水体出现严重的富营养化，为解决此问题，基于生物净化技术与工程措施相结合的思想，开展景观水体的净化处理示范工程研究。该工程根据河道特点，将生态廊道，生物沸石和生态浮床3种技术组合，对水体进行多重净化作用，水质得到了明显的改善。多级生态廊道可相对延长水流的流程，尽量减少死水区和短流。生物沸石本身具有物理截留和吸附作用，表面形成的生物膜对富营养化水体中的污染物能保持长效和稳定的去除作用。以陶粒为载体，悬挂立体弹性填料的多层次立体生态浮床通过植物和微生物的共同作用对水体进行生态修复。结果表明，该工程净化效果良好，对水体中的COD、TP、TN、NH4+-N、NO3--N的平均去除率分别为24%、46.24%、31%、24.43%、13.42%，达到示范工程的预期目标，并且夏季的处理效果高于冬季，该技术具有一定的应用前景。

Demonstration project of eutrophic water purification by a multicomponent system

Non-point source pollution from tea plantations in the upstream of West Lake caused severe eutrophication in the Longhong stream. Therefore, an in-stream treatment system combining biological purification technologies and engineering measures was devised to treat the water and to serve as a demonstration project for the purification of eutrophic landscape water bodies. Considering the characteristics of the stream channel, a treatment system combining an ecological corridor, bio-zeolite, and ecological floating beds, was used, which significantly improved the water quality. On the one hand, the multi-stage ecological corridor prolonged the flow path and prevented the formation of dead water zones and hydraulic short-circuiting. On the other hand, the bio-zeolite showed a physical interception effect, which also maintained long-term and stable removal of pollutants from the eutrophic waters by the biofilm formed on its surface. Moreover, the multi-layered three-dimensional ecological floating bed, which served as the carrier of ceramic particles and suspended elastic packing, ensured ecological restoration of the water body through the joint action of plants and microorganisms. Overall, the demonstration project exhibited good pollutants removal efficiencies of COD of 24%, TP of 46%, TN of 31%, NH4+-N of 24%, and NO3--N of 31%. Furthermore, a higher treatment efficiency was achieved in the summer than the winter. So, the project has a good application prospect.