人工湿地净化尾水效果的研究

Study on the tail water purification effect by constructed wetlands

采用种有美人蕉(Canna indica)的水平流和垂直流人工湿地对污水处理厂尾水进行处理,通过检测COD、TN、NO 3--N、NH 4+-N、TP等指标分析探讨温度、pH和进水指标等因素对湿地系统净化能力的影响.COD、NH 4+-N、NO 3--N、和TN去除率可分别高达66%、98%、62%和79%,其中NH 4+-N经湿地系统处理后可达到《地表水环境质量标准》(GB 18918-2002)I类标准.TN、NH 4+-N、TP在垂直流湿地系统中的去除率均高于水平流湿地系统,COD在水平流湿地系统中的平均去除率(53.5%)却高于垂直流湿地系统(47.3%).通过对水平流和垂直流湿地净化尾水效果的分析比较,表明垂直流湿地系统比水平流湿地系统在净化尾水方面更具优势.此外,Pearson相关性分析表明人工湿地系统中进水NH 4+-N浓度和气温对TN、NO 3--N和NH 4+-N的去除有显著影响.上述研究结果能为高效运用人工湿地处理污水处理厂尾水提供科学依据和技术指导.

The horizontal-flow and vertical-flow constructed wetlands with Canna indica were used to treat the tail water of sewage treatment plants,and the influences of temperature,pH and inlet water indexes on the purification capacity of wetland systems were analyzed and discussed by detecting COD,TN,NO 3--N,NH 4+-N and TP.The removal rates of COD,NH 4+-N,NO 3--N and TN could be up to 66%,98%,62%and 79%respectively,and NH 4+-N could reach the I standard of Surface Water Environmental Quality Standard after being treated by constructed wetland systems.The removal rates of TN,NH 4+-N and TP in the vertical-flow wetland systems were higher than those in the horizontal-flow wetland systems,while the removal rate of COD in the horizontal-flow wetland systems(53.5%)was higher than that in the vertical-flow wetland systems(47.3%).The analysis and comparison of the purification efficiencies of horizontal-flow and vertical-flow wetland systems show that the vertical-flow wetland systems have more advantages in tail water purification than the horizontal-flow systems.In addition,Pearson correlation analysis indicates that the influent NH 4+concentration and temperature have significant effects on the removal of TN,NO 3--N and NH 4+-N.The above results can provide scientific basis and technical guidance for the efficient use of constructed wetlands to treat the tail water from sewage treatment plants.