人工湿地不同植被净化污水效果及其氮磷累积研究

Research on Domestic Sewage Purification Efficiencies of Plants and N,P Accumulation in Biomass in Constructed Wetland

通过模拟垂直流人工湿地污水系统,研究了湿地植被鸢尾(Iris pseudacorus)、香蒲(Typha orientalis)、茭白(Zizania aquatica)和芦苇(Phragmites australis)对生活污水总氮(TN)、总磷(TP)、氨氮(NH_4^+-N)、生物耗氧量(BOD5)和化学耗氧量(CODCr)的去除效果及其植被对氮磷累积效应。结果发现:(1)人工湿地4种植被对生活污水的净化效果存在一定的差异,对污水各个指标的去除率随人工湿地的运营期均呈"V"型变化,基本表现为反弹期>稳定期>恢复期>启动期;(2)综合比较可知,通过人工湿地整个运营期来看,人工湿地植被能有效促进湿地对污水的去除效果,其中以茭白和鸢尾的去除效果较好,而4种湿地植被对TP的去除率最高,对TP,NH_4^+-N和CODCr的去除率差异不显著(p>0.05);(3)4种湿地植被地上和地下生物量表现出一致的变化规律,基本表现为鸢尾和茭白高于芦苇和香蒲,除了鸢尾以外,其他植被地上、地下生物量比(A/U)均大于1,4种植被地下生物量占总生物量的40%以上,并且地上部分N,P浓度高于地下部分N,P浓度,地上平均N,P积累量高于地下部分N,P积累量;鸢尾和茭白地上部分和地下部分N,P浓度和N,P积累高于芦苇和香蒲;(4)相关性分析表明人工湿地不同植被N,P积累量分别与生物量、N含量、P含量均呈显著的线性关系(p<0.01),生物量与N,P积累量的相关系数高于N含量和P含量的相关系数,表明人工湿地植被生物量对N,P积累量的影响大于植被体内N,P含量的影响,因此可以通过生物量来评价人工湿地植被对N,P的去除效果。

Four kinds of wetland plants, including Iris pseudacorus, Typha orientalis, Zizania aquatica and Phragmites australis were selected to study the removal efficiency of total nitrogen （TN）, total phosphorus （TP）, ammonia nitrogen （NH4^＋-N）, biological oxygen consumption （BOD5） and chemical oxygen consumption （CODcr） from domestic sewage by plants and the N, P accumulation in biomass in the constructed wetland. The results showed that： （1） the purification efficiencies of four kinds of wetland plants were different in a ＇V＇ type with the seasons which showed rebound period 〉 stabilization period 〉 recovery period 〉 period start; （2） the four kind of plants in constructed wetland could effectively promote the removal efficiency, which showed that Iris pseudacorus and Zizania aquatica were higher than rypha orientalis and Phragmites australis, while the removal efficiencies of TP, NH^＋-N and CODCr had no significant difference （p 〉 0. 05）; （3） the aboveground and the underground biomass showed Iris pseudacorus and Zizania aquatica were higher than Typha orientalis and Phragmites australis, and the ratios of most plants biomass aboveground （A/U） varied between 1 and 2 except for Iris pseudacorus, the underground hiomass accounted for more than 40% to total biomass, and the concentrations of nitrogen and phosphorus of aboveground biomass were higher than those in the underground biomass, which showed that Iris pseudacorus and Zizania aquatica were higher than Typha orientalis and Phragmites australis ; （4） correlation analysis showed that plant accumulations of nitrogen and phosphorus displayed significantly positive linear correlation with plant biomass and concentrations of nitrogen and phosphorus （p〈0.01）, and biomass could be used as an indicator to screen the appropriate artificial wetland plants.