点击次数：
论文类型：期刊论文
发表时间：2009-12-01
发表刊物：JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
收录刊物：SCIE、PubMed、Scopus
卷号：19
期号：12
页面范围：1656-1664
ISSN号：1017-7825
关键字：Partial nitrification; bioaugmented MBR; ammonia-oxidizing bacteria; microbial community
摘要：Bioaugmentation of bioreactors focuses on the removal of numerous organics, with little attention typically paid to the maintenance of high and stable nitrite accumulation in partial nitrification. In this study, a bioaugmented membrane bioreactor (MBR) inoculated with enriched ammonia-oxidizing bacteria (AOB) was developed, and the effects of dissolved oxygen (DO) and temperature on the stability of partial nitrification and microbial community structure, in particular on the nitrifying community, were evaluated. The results showed that DO and temperature played the most important roles in the stability of partial nitrification in the bioaugmented MBR. The optimal operation conditions were found at 2-3 mgDO/l and 30 degrees C, achieving 95% ammonia oxidization efficiency and nitrite ratio (NO(2)(-)/NO(x)(-)) of 0.95. High DO (5-6 mg/l) and low temperature (20 degrees C) had negative impacts on nitrite accumulation, leading to nitrite ratio drop to 0.6. However, the nitrite ratio achieved in the bioaugmented MBR was higher than that in most previous literatures. Denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) were used to provide an insight into the microbial community. It showed that Nitrosomonas-like species as the only detected AOB remained predominant in the bioaugmented MBR all the time, and coexisted with numerous heterotrophic bacteria. The heterotrophic bacteria responsible for mineralizing soluble microbial products (SMP) produced by nitrifiers belonged to the Cytophaga-Flavobacterium-Bacteroides (CFB) group, and alpha-, beta-, and gamma- Proteobacteria. The fraction of AOB ranging from 77% to 54% was much higher than that of nitrite-oxidizing bacteria (0.4-0.9%), which might be the primary cause for the high and stable nitrite accumulation in the bioaugmented MBR.