高浓度Mg2+对厌氧氨氧化菌的影响

采用序批式和连续流反应器,考察Mg^2+浓度对厌氧氨氧化菌脱氮性能和微生物形态的影响。结果表明,厌氧氨氧化菌的最适Mg^2+投量为0.4 mmol/L,抑制投加量为2.4 mmol/L。在相同的条件下,设置对照试验,控制进水Mg^2+浓度分别为0.4和2.4 mmol/L,经过119 d的运行,后者的TN去除负荷降至1.33 g/(gVSS·d),为0.4 mmol/L时的63.6%;NO3^-N生成量与氨氮去除量之比从0.2降至0.13 ,表明高浓度Mg^2+对厌氧氨氧化菌活性产生抑制,导致其脱氮效率和生长速率降低。扫描电镜图像表明,Mg^2+浓度为2.4 mmol/L环境中的厌氧氨氧化菌更容易发生团聚并形成团簇结构。FISH分析显示,当Mg^2+浓度过高时,一部分厌氧氨氧化菌因没有适应环境而死亡,导致DOC升高,厌氧氨氧化菌在总菌中的比例下降。另外,Mg^2+浓度从2.4 mmoL/L降至0.4 mmol/L后的25d内,厌氧氨氧化菌活性得到恢复。

Influence of Mg2+ on Anammox Bacteria: Adaptability and Activity Recovery Strategy

The effect of Mg^2+ concentration on the nitrogen removal perfonnance and microbial morphology of anaerobic ammonium oxidation ( Anammox) process was investigated by using sequencing batch reactor and continuous flow reactor. It was demonstrated that 0.4 mmol/L was the optimal condition , whereas the reaction was inhibited at 2. 4 mmol/L. Under the same experiment condition, the influent concentration of Mg^2+ was controlled at 0. 4 mmol/L and 2.4 mmol/L, respectively. During the long-term operation of 119 days, TN ( total nitrogen) removal load decreased by 36. 4% to 1. 33 g/(gVSS·d ) when adding 2.4 mmol/L of Mg^2+, which compared with 0.4 mmol/L of Mg^2+. Furthermore, the decrease of reaction ratio of NO3^--N production to NH;- N consumption from 0.2 to 0.13 indicated that high concentration of Mg^2+ caused the inhibition on Anammox bacteria, and resulted in the reduction of TN removal load and growth velocity. SEM images and FISH analysis showed that it was more likely to form Anammox cluster since the proportion of Anammox bacteria decreased with the increasing of DOC when the concentration of Mg^2+ was 2.4 mmol/L. In addition, the nitrogen removal load recovered within 25 days after the concentration of Mg^2+ decreased from 2.4 mmol/L to 0.4 mmol/L.