Combined multi-level ecological unit system for deeply treating secondary effluent of sewage plant

The invention discloses a combined multi-level ecological unit system for deeply treating secondary effluent of a sewage plant. The system sequentially consists of a water distribution tank, an ecological pond, a secondary constructed wetland and a submerged plant pond. When the system runs, tail water of a sewage treatment plant sequentially passes through the ecological pond, a subsurface flow wetland, a surface flow wetland and the submerged plant pond, and is purified under the joint action of a filler-microorganism-plant system, and effluent is high in water quality and stable. The system has the advantages of capability of efficiently removing nitrogen and phosphorus, low capital construction cost, no power consumption, convenience for subsequent maintenance and operation and the like, and has a landscaping value, and the aim of deeply treating the effluent can be fulfilled. 本发明公开了种深度处理污水厂二级出水的多级生态单元组合系统，该系统依次由配水槽、生态塘、二级人工湿地和沉水植物塘组成。系统运行时，污水处理厂尾水依次经过生态塘、潜流湿地、表流湿地和沉水植物塘，在填料-微生物-植物系统联合作用下进行净化处理，其出水水质好且稳定。