美人蕉、梭鱼草和黄菖蒲人工湿地系统对养猪废水的脱氮特征研究

Study on Nitrogen Removal Characteristics of Swine Wastewater in the Constructed Wetland Systems of Canna indica,Pontederia cordata and Iris pseudacorus

湿地植物是人工湿地系统的重要组成部分之一,不同植物构建的湿地系统有不同的脱氮特征。通过野外小区试验,以3种常见挺水植物——美人蕉(Canna indica)、梭鱼草(Pontederia cordata)、黄菖蒲(Iris pseudacorus)为研究对象,在水力停留时间为7 d时探究其对养猪废水(沼液)的脱氮特征。结果表明:3种植物湿地系统对TN、NH 4+-N和NO 3--N的去除效果均为梭鱼草>黄菖蒲>美人蕉,脱氮量分别为3.93、3.74和2.96 g·m^-2·d^-1,其中微生物转化脱氮居主导地位,分别占去除总量的66%、73%和64%,底泥吸附(13%、10%和22%)和植物吸收(21%、17%和14%)途径占比均较低。3种挺水植物在养猪废水(沼液)中均可存活,其中梭鱼草生物量较大,湿地脱氮效果最好,适合作为养猪废水(沼液)处理的先锋植物;黄菖蒲根系相对发达,低温阶段生长良好,与梭鱼草存在季节方面的互补性;美人蕉耐受能力较强,但净化能力较弱。

Wetland plants are one of the critical components of the constructed wetland,and wetland systems constructed by different plants have different nitrogen removal characteristics.In this study,three emerged plants,Canna indica,Pontederia cordata and Iris pseudacorus,were selected for the field control experiment under the hydraulic retention time of 7 days.The nitrogen removal characteristics of the three plants on treating swine wastewater were investigated.The results show that the removal rates of TN,NH 4^+-N,and NO 3^--N were P.cordata>I.pseudacorus>C.indica,and the nitrogen removal loads were 3.93,3.74 and 2.96 g·m^-2·d^-1,respectively.Among the wetland systems of the three emergent plants,microbial transformation was the most important way to the removing of nitrogen,accounting for 66%,73%,and 64%of the total nitrogen removal amount,respectively,and the amount of sediment adsorption(13%,10%,and 22%)and plant uptake(21%,17%,and 14%)were lower.P.cordata had the largest biomass,the best growth and nitrogen removal rate and was suitable to be the pioneer plant for swine wastewater treatment.The root system of I.pseudacorus was the most developed,and it grew well under low temperature conditions,which can be a seasonal complement to P.cordata.C.indica can grow well in the swine wastewater,but its purification capacity was weak.