多级表面流人工湿地在鄱阳湖区农村面源污染控制中的应用

Application of Multi-Surface Flow Constructed Wetland to Rural Non-point Source Pollution Control in Poyang Lake Region

通过构建多级表面流人工湿地探讨了鄱阳湖区农村面源污染的控制机制,并对湿地系统污水处理工艺进行了研究。研究表明,系统污染物COD,TP,NO3-—N和NO2-—N负荷年消减量为608.46,3.22,8.14和0.62kg/a,单位面积年消减量分别为3976.83,21.04,53.21和4.05kg/(hm2.a)。系统对污染物COD,TP,NO3-—N和NO2-—N的去除率分别为48.9%,73.5%,58.7%和54.7%,且污染物COD和TP去除主要集中在第一级芦苇湿地。表面流人工湿地因具有较强的复氧功能,但限制NO3-—N反硝化作用。为提高NO3-—N的去除率,对湿地系统硝化与反硝化机理进行了探讨,并提出引流部分污水直接进入第3级湿地与改第3级湿地为潜流型湿地相结合的有效措施。该系统不仅对鄱阳湖区农村面源污染控制提供了技术依据而且为其它湖滨提供了示范。

By constructing multi-surface flow wetland,the effects of wetland system were examined and the control of rural non-point source pollution around Poyang Lake was discussed.Results showed that the total reductions of COD,TP,NO-_3—N,and NO-_2—N in the wetland system were 608.46,3.22,8.14,and 0.62 kg/a and the reductions of COD,TP,NO-_3—N,and NO-_2—N per hectare were 3976.83,21.04,53.21,and 4.05 kg/（hm2·a）,respectively.The removal rates of COD,TP,NO-_3—N,and NO-_2—N in the wetland system were 48.9%,73.5%,58.7%,and 54.7%,respectively,and the COD and TP removal mainly occurred in the first reed wetland.Because the constructed wetland had a strong function of recovering oxygen,denitrification of NO-_3—N was limited.In order to enhance NO-_3—N removal rate,we discussed the mechanisms of nitrification and denitrification in wetland system and put forward the effective measure that part of the wastewater drained directly into the end of three wetlands and the end of three wetlands changed into subsurface flow wetland.In short,the wetland system not only provided a technical foundation for the control of rural non-point source pollution around Poyang Lake,but also afforded a demonstration for other lakefronts.