四种不同植物湿地对不同C/N比生活污水的净化效果与季节动态

进水浓度、C/N比、植物种类是影响垂直流型人工湿地对生活污水净化效果的重要因素.本文主要研究了菖蒲(Acorus calamus)、香蒲(Typha orientalis)、千屈菜(Lythrum salicaria)和水葱(Scirpus Validus)等4种植物湿地在不同碳添加及C/N比处理条件下对模拟生活污水的净化效果和季节动态.结果表明,4种湿地植物在不同C/N比(2.5∶1、5∶1和10∶1)进水条件下均能正常生长.在一个生长季内4种湿地植物对主要污染物的平均去除效率为:COD 63.41%~78.02%,TN 33.19%~52.86%,TP 52.64%~73.16%.当C/N为5∶1时,香蒲湿地的COD和TP去除效果最佳,而当C/N为2.5∶1时,菖蒲湿地的TN去除率最高.夏末秋初(7—9月)人工湿地的净化效果较好,而冬季(11月—翌年1月)去除效果明显下降.总体而言,合理地调控进水浓度、C/N比,选择最佳的湿地植物,可显著提高垂直流型人工湿地对生活污水的净化效果.

The seasonal variation performance of vertical subsurface flow constructed wetlands with four plants under different influent C/N ratios

The influent water quality, C/N ratios and wetland plants could affect the treatment performance of vertical-subsurface flow constructed wetlands (VSFW). In this study, four kinds of wetland plants, named Acorus calamus, Typha orientalis, Lythrum salicaria and Scirpus Validus, were cultivated in the VSFW under different C/N ratios of influent to test the nutrient removal efficiencies and determine the seasonal variation. The results showed that all species grew well under the C/N ratios of 2.5:1, 5:1 and 10:1. The average removal rates of chemical oxygen demand(COD), total nitrogen(TN) and total phosphorous(TP) were 63.41%~78.02%, 33.19%~52.86% and 52.64%~73.16%, respectively. When the C/N ratio was 5:1, COD and TP were effectively removed in VSFW planted with Typha orientalis and Scirpus Validus. VSFW planted with Acorus calamus demonstrated higher N removal efficiency under the C/N ratio of 2.5:1. During the experimental period, the relatively higher nutrient removal efficiency (RE) was achieved from July to September. While RE decreased significantly from November to January. In general, the appropriate C/N ratio of influent water and wetland plant were beneficial to achieve the optimal effect of nutrients removal.