冬季强化水平潜流人工湿地微污染水体脱氮研究

Study on Denitrification of Micro-polluted Water by Enhanced Horizontal Subsurface Wetland in Winter

为微生物的硝化反硝化作用是湿地除氮的主要途径,针对人工湿地易受冬季低温、植物枯萎的影响,其脱氮能力显著降低的现象,重点研究了DO,pH值,温度和有机碳源对潜流湿地脱氮效果的影响。研究结果表明,通过在潜流湿地表面覆盖植物残体和薄膜,可提升湿地床内水温3~7℃,对TN的去除率维持在32%~42%;通过布设导气管和周期性调节湿地床内水位,可维持湿地基质床内DO质量浓度不低于1.0mg/L,硝化率维持在19%~26%;试验期间,进水pH值6.8~8.1稳定且适宜硝化反硝化进行;玉米芯可持续为反硝化菌提供纤维素碳源,释放的碳源能很好的被反硝化菌利用,从而促进氮的去除,冬季对微污染水体中氮的去除率可以达到64%。

The rate of denitrification was decreased remarkably by constructed wetland in winter because the system was affected by low temperature and plant dormancy. Nitrification and denitrification is the principal pathway of removal TN in wetland, this paper studied the influence factor temperature, DO, pH and organic carbon source on the removal of TN in subsurface constructed wetland. The result showed that covering plant remnants and plastic film on the subsurface constructed wetland could raise temperature of wastewater in the wetland 3 ~ 7 ℃, The removal rate of TN remained at 32% to 42%;Setting airway and adjusting the height of water periodically could raise the concentration of DO in subsurface constructed wetland no less than 1.0 mg/L, The nitrification rate remained at 19%~ 26%;The pH of inflow(6.8 ~ 8.1) was stable and suitable for microorganisms in experimental stage;Corncob can provide cellulose carbon source for denitrifying bacteria persistently, so as to promote denitrification effect, the removal rate of TN could reach 64% for micro-polluted water in winter.