利用充氧和回流强化波形潜流人工湿地的脱氮效果

为提高人工湿地对氨氮的去除能力,在本实验中将传统波形潜流人工湿地进行改造,于第2个波形区间内安装曝气管,改善湿地内氧气分布状况,提高湿地的硝化效果,并与传统波形潜流人工湿地进行对照试验.结果表明,由于大部分COD在第2波形区间充氧过程中得到去除,因此在第3波形区间硝化菌成为优势菌种,使湿地中硝化程度达到90%以上,出水中COD值大幅下降,耐进水冲击负荷的能力明显加强.在第2阶段将湿地出水按50%的回流比回流湿地起端,原污水在湿地起端和1/3处分别进水,证明1/3处进水总氮去除率最高,达到50%左右,水力负荷在0.8 m³/(m²·d)时,COD有机负荷达到56～112 g/(m²·d),氨氮负荷达到20～28 g/(m²·d).

Removal Nitrogen in Wavy Subsurface-flow Constructed Wetland Utilizing Aeration and Recirculation

To improve the removal rates of ammonium nitrogen in the constructed wetlands, the traditional wavy subsurface-flow constructed wetland (W-SFCW) was modified to install the aeration tube in the second wave interval to improve the DO and the nitrification rates within the constructed wetlands. It was found that as most of COD had been removed in the second wave interval, nitrifying bacteria become dominant in the third wave interval, which led to the nitrification extent reaching more than 90%, and the ability to endure the impact of hydraulic loading was enhanced. Recirculation rates of 50% were adopted to evaluate the effect on TN removal. It showed that with effluent recirculation the average removal efficiencies of TN obviously increased to 50% when the wastewater entered 1/3 of the wetland not infall. The hydraulic loading of wetland reached 0.8 m3/(m2 x d), and COD organic loading was 56-112 g/(m2 x d), and the ammonium loading rate was 20-28 g/(m2 x d).