低温季大型表流湿地对微污染水体脱氮效果及优化运行

低温季表流湿地脱氮效果下降是业内公认的难题,长期以来备受人们的关注,但针对大型表流湿地处理微污染水体的相应研究开展较少。综述了表流湿地脱氮机理及低温季限制因素,同时以盐龙湖工程的表流湿地单元为实例,分析了其在低温季对微污染水体中各形态氮素的净化效果,从优化湿地运行角度出发开展研究。结果表明,在低温季表流湿地进水的TN平均值为1.16~3.35 mg/L条件下,TN、NH3-N、硝态氮、Org-N的平均去除率为13%、35%、15%、-14%;显著影响表流湿地出水TN浓度的因素为湿地运行面积、进水负荷、温度以及进水浓度(p 湿地运行面积(负相关)> 进水负荷(负相关)> 温度(负相关)。显著影响表流湿地NH3-N出水浓度的因素为温度与进水浓度(p温度(负相关);当HRT从3-N的平均去除率分别由6%、26%提升到17%与41%。

Effect of nitrogen removal of a large surface-flow constructed wetland treating micro-polluted water under low temperature seasons and operation optimization

The declining of nitrogen removal efficiency of constructed wetland under low temperature seasons is a recognized confusion in the line, but less research was conducted on large SFW treating micro-polluted water by far. On the basis of filed data of SFW unit, Yanlong Lake, the nitrogen removal mechanism and the affecting factors of SFW under low temperature seasons were summarized, and the nitrogen removal efficiency was analyzed from the angle of operation optimization. Results showed that under low temperature seasons, the average removal rates of TN, NH3-N, nitric nitrogen, Org-N by the SFW were 13%, 35%, 15% and -14%, respectively. Wetland area, water load, temperature and TN inflow concentration had significant effect on TN outflow concentration (p wetland area> water load> temperature. Nevertheless, temperature and NH3-N inflow concentration had significant effect on NH3-N outflow concentration (p3-N inflow concentration>temperature. As HRT extended from3-N increased from 6%, 26% to 17% and 41%, respectively.