磷对混养反硝化污泥活性和微生物群落结构的影响

生物反硝化脱氮是现在最广泛使用的去除水中NO-3-N的方法之一,混养反硝化因其综合了异养和自养反硝化的共同特性而引人关注.本实验探究添加一定量无机磷前后反硝化污泥活性及其微生物群落结构的变化.结果表明,混养反硝化污泥在无磷供给时也能进行反硝化反应,但磷的添加可显著提高其生物量和反硝化活性,反硝化污泥的异养反硝化活性明显高于自养部分,添加无机磷之后,自养和异养反硝化速率(以N/VSS计)分别可达0.056 mg·(L·min·g)-1和0.232mg·(L·min·g)-1,分别为加磷前的2.9和3.9倍.此外,微生物群落分析表明,投加磷之后混养污泥中反硝化菌占比显著增加,从13.47%增加到44.82%;优势菌属发生显著变化,添加无机磷使自养、异养以及兼性反硝化菌的生长均得到有效促进.

Effects of Phosphorus on the Activity and Bacterial Community in Mixotrophic Denitrification Sludge

Biological denitrification is now one of the most widely applied techniques to remove nitrogen from the aquatic environment, and mixotrophic denitrification has gained attention as it takes the characteristics of both heterotrophic and autotrophic denitrification. This study investigated the biological denitrification efficiency and the bacterial community structure of sludge sampled from a mixotrophic denitrification reactor, before and after adding a certain amount of phosphate. The results showed that the bacteria have the capability of denitrification even without phosphorus, but the addition of phosphorus could significantly improve the biomass and the denitrification activity. After phosphate was added, the autotrophic and heterotrophic denitrification activity increased to 0.056 mg·(L·min·g)^-1 and 0.232 mg·(L·min·g)^-1 on N/VSS, which was 2.9 and 3.9 times that of the sludge activity before phosphorus addition, respectively. The bacterial community structure illustrated that the denitrifiers increased remarkably from 13.47% to 44.82% and that the dominate bacteria have also changed. Meanwhile, the growth of autotrophic, heterotrophic, and mixtrophic bacteria were all improved significantly after phosphorus was added.