Two Artificial Wetland Treatment Comparison Of Low Concentrations Of Sewage

Lake Eutrophication has been become a serious problem in our country. As an effective way to solve this problem, Nonpoint pollution control was attach importance to people increasingly. Constructed wetlands is a new sewage technolygy with low cost and less energy for N,P removal, less requirement of technique and management, compared to conventional wastewater treatment processes, can be used to control the city's nonpoint pollution. As an important part of system, macrophyte plays an important role in the constructed wetland.This paper introduced the concept, decontamianat mechanism, the status of research both in and outside the nation, the application of wetland treatment technology in china. Meanwhile, emphasize the advantage of constructed wetland ,the selection of plants and it's role in the constructed wetland .Consulting the sewage of Da-Ming lake in Jinan, vertical flow constructed wetland and subsurface constructed wetland were used to treat low strength wastewater. The removal efficiency of constructed wetland was investigated for COD, TN, TP at different hydraulic retention time and different concentration wastewater. Meanwhile, study the function of aquatic macrophyte to the removal efficiency of pollution. The result showed:Different water flows have different remove efficiency. At hydrolic retention time is 24h,the remove rate of COD, TN, TP was 75.2%, 66.3% ,82.8% in the subsurface wetland and 70.2%, 76.2%, 93.3% in the vertical flow wetland, the removal efficiency of TN, TP was higher and COD was lower in the vertical flow wetland compared with subsurface wetland;The change of hydraulic loading in constructed wetland has the effect on remove efficiency between two types of water flow. When the concentration of inflow water was 120mg/L, 2mg/L, 20mg/L, the removal rate of two systems was higher. In the subsurface flow constructed wetland, the change of hydraulic loading has higher TN removal efficiency. While in the vertical flow constructed wetland, the change of hydraulic loading has higher TP and COD removal efficiency.Aquatic macrophyte influence the remove rate of wetland system, macrophyte have the ability of N, P removal , it played an important role in the constructed wetland.