三级绿狐尾藻表面流人工湿地对养殖废水处理效应研究

Performance of Three-stage Surface Flow Constructed Wetlands Planted with Myriophyllum aquaticum Gaudich for Swine Wastewater Treatment

提高人工湿地对养殖废水的处理效果是当前人工湿地需要解决的重要问题。本文以绿狐尾藻（Myriophyllum aquaticum Gaudich）为湿地植物，在野外构建三级表面流人工湿地，以高污染养猪废水为处理对象，分析废水中铵态氮（NH4＋-N）、总氮（TN）、总磷（TP）和化学需氧量（COD）在人工湿地中的去除效应，并解析它们与水体温度、溶解氧（DO）、pH和氧化还原电位（Eh）等指标的关联性。结果表明，绿狐尾藻人工湿地对NH4＋-N、TN、TP和COD平均去除率分别为88.3%、86.4%、76.3%和82.3%，出水平均浓度分别为45、86、14和188 mg/L。人工湿地进水负荷与人工湿地去除负荷呈显著的正相关关系（R2 ≥ 0.80，P〈 0.01），去除负荷随进水负荷增加而增加。根据Pearson相关分析，人工湿地对NH4＋-N、TN、TP的去除率与水体DO、Eh和温度有显著相关性（P〈0.01），而对COD的去除率仅与温度存在显著的相关关系（P 〈 0.05），说明人工湿地对不同污染物的去除机制存在差异。主成分分析发现水体温度是人工湿地对NH4＋-N、TN、COD去除的主要影响因素，水体Eh对人工湿地去除TP的关联性最大。这对改善人工湿地对污染物的去除效应至关重要。

Improving treatment efficiency of constructed wetlands （CWs） has been an important issue. In this present study, Myriophyllum aquaticum Gaudich was selected as a wetland plant to construct three-stage surface-flow CWs in the field condition. High strength swine wastewater was used as the treatment target. The CWs were used for removal of ammonia nitrogen （NH4＋-N）, total nitrogen （TN）, total phosphorus （TP） and chemical oxygen demand （COD） from swine wastewater, and effects of water temperature, dissolved oxygen （DO）, pH and oxidation-reduction potential （Eh） on removal of pollutants by CWs were analyzed. The results showed that the average removal efficiencies of NH4＋-N, TN, TP and COD in CWs were 88.3%, 86.4%, 76.3%, and 82.3%, respectively, and the average effluent concentrations were 45, 86, 14 and 188 mg/L. The significant positive correlations were observed between the influent loading rates of pollutants and removal rates by CWs （R2 ≥ 0.80, P〈0.01）, suggesting that the removal rates increased with the increasing loading rates of pollutants. The results of Pearson correlation analysis showed that the removal efficiencies of NH4＋-N, TN and TP by the CWs were significantly correlated with DO, Eh and temperature （P〈0.01）, while the COD removal efficiencies were only significantly correlated with temperature （P〈0.05）. This discrepancy indicated that there are different removal mechanisms of different pollutants by the CWs. The principal component analysis showed that temperature had the greatest effect on the NH4＋-N, TN and COD removal, whereas Eh had the greatest effect on TP removal in the CWs. The results are helpful for choosing the crucial engineering measures when improving the removal efficiency of pollutants in the CWs.