title: Analysis of nitrification efficiency and microbial community in a membrane bioreactor fed with low COD/N-ratio wastewater.
abstract: In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR). Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress. The enrichment of nitrifiers in an MBR with a low COD/N-ratio demonstrated that this condition stimulated nitrification, and that the community distribution of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) resulted in faster nitrite uptake rates. Further, ammonia oxidation was the rate-limiting step during the full nitrification.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, PR China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Ma
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Wang
authors.forename: Chaowei
authors.initials: C
authors.lastname: Zhu
authors.forename: Shumeng
authors.initials: S
authors.lastname: Liu
authors.forename: Qiaoying
authors.initials: Q
authors.lastname: Wang
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D001483:Base Sequence; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D016000:Cluster Analysis; D052836:Heterotrophic Processes; D008567:Membranes, Artificial; D064307:Microbiota; D058465:Nitrification; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis*; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification
chemical_list: D000641:Ammonia; D008567:Membranes, Artificial; D009573:Nitrites; D009584:Nitrogen; D062065:Wastewater