title: Ammonia oxidizing bacteria community dynamics in a pilot-scale wastewater treatment plant.
abstract: BACKGROUND
  Chemoautotrophic ammonia oxidizing bacteria (AOB) have the metabolic ability to oxidize ammonia to nitrite aerobically. This metabolic feature has been widely used, in combination with denitrification, to remove nitrogen from wastewater in wastewater treatment plants (WWTPs). However, the relative influence of specific deterministic environmental factors to AOB community dynamics in WWTP is uncertain. The ecological principles underlying AOB community dynamics and nitrification stability and how they are related are also poorly understood.
  
  
  RESULTS
  The community dynamics of ammonia oxidizing bacteria (AOB) in a pilot-scale WWTP were monitored over a one-year period by Terminal Restriction Fragment Length Polymorphism (T-RFLP). During the study period, the effluent ammonia concentrations were almost below 2 mg/L, except for the first 60 days, indicting stable nitrification. T-RFLP results showed that, during the test period with stable nitrification, the AOB community structures were not stable, and the average change rate (every 15 days) of AOB community structures was 10% ± 8%. The correlations between T-RFLP profiles and 10 operational and environmental parameters were tested by Canonical Correlation Analysis (CCA) and Mantel test. The results indicated that the dynamics of AOB community correlated most strongly with Dissolved Oxygen (DO), effluent ammonia, effluent Biochemical Oxygen Demand (BOD) and temperature.
  
  
  CONCLUSIONS
  This study suggests that nitrification stability is not necessarily accompanied by a stable AOB community, and provides insight into parameters controlling the AOB community dynamics within bioreactors with stable nitrification.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.forename: Xianghua
authors.initials: X
authors.lastname: Wen
authors.forename: Yu
authors.initials: Y
authors.lastname: Xia
authors.forename: Ma
authors.initials: M
authors.lastname: Hu
authors.forename: Fang
authors.initials: F
authors.lastname: Zhao
authors.forename: Kun
authors.initials: K
authors.lastname: Ding
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D058465:Nitrification; D010084:Oxidation-Reduction; D010865:Pilot Projects; D012150:Polymorphism, Restriction Fragment Length; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D000641:Ammonia