title: [Microbial ecology analysis of the biofilm from two biological contact oxidation processes with different performance].
abstract: This study investigated the performance of one-step aerobic biological oxidation process and anoxic/aerobic two-step biological oxidation process treating modeled river water containing low carbon and rich ammonia. Biofilm microbial ecology was analyzed with multiple molecular technologies including PCR-DGGE, FISH/CLSM and FISH/FCM to investigate the succession of bacteria community and space distribution along with abundance of the main functional bacteria, and to research the micro-influential factors and the mechanism of different biological contact oxidation processes for their performance. Results showed that two-step contact oxidation process achieved higher removal percentage than that of the one-step process, with COD and NH4(+) -N removal enhanced about 10% and 32%-59%, respectively. A much thicker biofilm was obtained by the one-step process compared to the two-step process, and nitrobacterium was mainly distributed in the depth of 180-200 microm and 105-125 microm, respectively. PCR-DGGE results found that the two-step process demonstrated less microbial diversity than that of the one-step process, FISH/FCM results showed that ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) abundance increased in the two-step process with the increase of operation time, while that of the one-step process declined. Experiment results demonstrate that functional partitioning of the anoxic-aerobic two-step biological contact oxidation process could be in favor for harvesting nitrobacteria and other special bacteria in different reactor spaces, which can improve removal efficiency for organics and ammonia finally.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control/Key Laboratory of Water and Sediment Sciences of Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China. bnuqian@163.com
authors.forename: Yin
authors.initials: Y
authors.lastname: Qian
authors.forename: Xiang-Chun
authors.initials: XC
authors.lastname: Quan
authors.forename: Yuan-Sheng
authors.initials: YS
authors.lastname: Pei
authors.forename: Jing-Yun
authors.initials: JY
authors.lastname: Ma
authors.forename: Kun
authors.initials: K
authors.lastname: Tao
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D017753:Ecosystem; D009576:Nitrobacter / Q000378:metabolism*; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000302:isolation & purification / Q000378:metabolism; D045483:Rivers; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000644:Quaternary Ammonium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen