多级潮汐流人工湿地对污泥厌氧消化液中氨氮及有机物的去除特征

Characteristic of ammoniacal nitrogen and organic matter removal from supernatant of anaerobic digested sludge using a multi-stage tidal-flow constructed wetland

针对城市污水处理厂污泥厌氧消化液回流而引起城市污水处理厂处理系统内氨氮累积的问题,采用多级潮汐流人工湿地(MTF-CWs),研究MTF-CWs对污泥厌氧消化液中氨氮和有机物的去除特征及其主要去除途径。经过260 d的运行,结果表明,NH_4^+-N和COD平均进水浓度分别为859.55 mg·L^(-1)和446.52 mg·L^(-1),MTF-CWs对NH_4^+-N和COD均有较好的处理效果,平均去除率分别为66.50%和47.10%。在MTF-CWs中,转化为NO_2^--N和NO_3^--N占被去除NH_4^+-N的73.21%,硝化反应是NH_4^+-N去除的主要途径,MTF-CWs的平均硝化速率为0.3 kg·(m^3·d)^(-1)。TN的平均去除率为17.63%,去除效果较差,其原因在于原水中缺少反硝化所需要的碳源。

The supernatant of anaerobic digested sludge is currently returned back to the main wastewater treatment stream and results in the accumulation of ammoniacal nitrogen（ NH_4＋-N） in the municipal wastewater treatment plant（ WWTP）. To eliminate NH_4~＋-N accumulation in municipal WWTP,a lab-scale multi-stage tidal flow constructed wetlands（ MTF-CWs） was employed to investigate the efficiency and dominating pathway of NH_4＋-N and organic matter removal from the supernatant of anaerobic digested sludge. The results showed that MTF-CWs present excellent NH_4＋-N and chemical oxygen demand（ COD） removal performance during 260 days operation. The MTF-CWs achieved 66. 50% and 47. 10% removal efficiencies for NH_4＋-N and COD,respectively,at mean influent concentrations of 859. 55 mg · L-1and 446. 52 mg · L-1,respectively. The results also showed that 73. 21% of the removed NH_4＋-N can be converted to nitrite and nitrate,indicating that nitrification is the dominating pathway for NH_4＋-N removal in MTF-CWs. The average nitrification rate is 0. 3 kg·（ m3·d）-1.The average TN removal efficiency is 17. 63%,indicating that the TN removal performance of MTF-CWs is quite poor,because the lack of available carbon for denitrification.