不同C/N下人工湿地的脱氮效果及其强化措施

Nitrogen removal and its amplifying test in constructed wetland under different C /N

以人工湿地为研究对象,分析了不同C/N下人工湿地的脱氮效果。结果表明,C/N为10时,TN、NO-2-N和COD平均去除率分别为(75.36±10.55)%、(86.34±9.23)%和(67.60±4.10)%,都显著高于其他2组系统(p=0.006、0.001、0<0.01);随着C/N的增加,NO-3-N去除率呈现出上升的趋势;NH+4-N刚好相反,C/N为1时,明显要高于其他2种情况(p=0<0.05),平均去除率为(65.42±14.31)%。针对C/N为1时人工湿地脱氮效率较低(51.29±14.48)%的情况,对系统进水采取了添加一定量好氧反硝化细菌固定化小球并曝气12 h的强化实验措施。结果发现,强化实验条件下TN、NO-2-N和NO-3-N去除率均提高了10%以上,且都要明显高于非强化实验条件(p=0.003、0、0<0.01),同时NH+4-N和COD去除率没有明显差异,研究结果表明,从微生物角度对系统进水进行前处理有助于提高人工湿地脱氮效率。

The aim of this study was to investigate the removal of nitrogen and the impact of different C/N in constructed wetland. Results indicated that the average removal competence of TN, NO2- -N, COD were （75.36 ± 10.55 ） %, （ 86.34 ± 9.23 ） % and （67.60 ± 4. l0 ） %, respectively, which were significantly higher than that of other two systems （p =0. 006,0. 001,0 〈0.01） when C/N was 10; with the increasing of C/N, the re- moval capability of NO3 -N presented a rising trends ; while at C/N = 1, the average removal amount of NH4 -N was （65.42 ± 14.31 ）% , showing the largest in those three different C/N （p = 0 〈 0.05）. Targeting at the de- fect of lower nitrogen removal quantity at C/N = 1, an amplifying test was adopted which was adding some aero- bic denitrification bacteria immobilized beads into influent and aerating for 12 h. And the experimental results showed that the removal capacity of TN, NO2- -N, NO3 -N increased by more than 10% and considerably higher than non-amplifying test （p =0. 003,0,0 〈0.01 ） , but there were no apparent differences on NH4＋ -N and COD. From the aspect of microorganisms, the pre-treatment of influent contributed to the improvement of nitrogen re- moval ability in constructed wetlands.