纳米银颗粒对膜生物反应器运行性能及硝化细菌丰度的影响

考察了0.10 mg/L纳米银对膜生物反应器(MBR)运行、氨氧化菌(AOB)和亚硝酸盐氧化细菌(NOB)丰度的影响。运行试验结果表明,在投放纳米银前后,处理系统对化学需氧量(COD)平均去除率为95.4%和94.1%,处理水中的总氮(TN)以硝态氮为主,硝态氮平均质量浓度前后分别为12.5 mg/L和13.2 mg/L,因此,在纳米银颗粒影响下,MBR仍能达到普通MBR的处理效果。实时定量聚合酶链反应(QPCR)结果表明:在整个运行周期内,AOB与NOB菌群的基因数量都处于107数量级,且硝化螺旋菌Nitrospira为优势NOB;结合银离子的变化规律可知,纳米银大部分富集到污泥中,但硝化菌群的丰度没有受到长期投放纳米银颗粒的影响。

Impact of Silver Nanoparticles on Performance of MBR Operation and Abundance of Nitrobacteria

The influences of low concentration of silver nanoparticles(0.10 mg/L)on the performance of membrane bioreactors(MBR),population structure and dynamics of ammonia-oxidizing bacteria(AOB)and nitrite-oxidizing bacteria(NOB)was investigated.The results indicated that before and after the addition of silver nanoparticles,removal efficiencies of the process for chemical oxygen demand(COD)had been reached 95.4%and 94.1%,respectively.Total nitrogen(TN)in the treated water were mainly in the form of nitrate nitrogen,while the concentration of NO-3-N before and after nano-sivler loading were 12.5 mg/L and 13.2 mg/L.MBR could achieve the same effect of common MBR on the influence of silver nanoparticles.Real-time QPCR results showed that the abundance of AOB and NOB were on the same order of 107,and Nitrospira was the dominant species of NOB.Results showed that combined with Ag+change rule,silver nanoparticles were concentrated in the sludge,but the abundance of nitrifying bacterial was not impacted by continuous long-term silver nanoparticles loading at the low concentration of silver.