title: Microbial activity balance in size fractionated suspended growth biomass from full-scale sidestream combined nitritation-anammox reactors.
abstract: The purpose of this study was to determine the abundance, distribution and activity of aerobic ammonia-oxidizing bacteria (AOB) and anammox in size fractionated aggregates from full-scale suspended growth combined nitritation-anammox sidestream reactors. Plants with or without a cyclone device were also studied to assess a purported enrichment of anammox granules. Specific aerobic ammonium oxidation rates (p=0.01) and specific oxygen uptake rates (p=0.02) were significantly greater in flocs than in granules. AOB abundance measured using quantitative FISH was significantly higher in flocs than in granules (p=0.01). Conversely, anammox abundance was significantly greater in granules (p=0.03). The average ratio of anammox/AOB in systems employing hydrocyclone separation devices was 2.4, significantly higher (p=0.02) than the average ratio (0.5) in a system without a hydrocyclone. Our results demonstrate substantial functional and population-level segregation between floccular and granular fractions, and provide a key corroboration that cyclone separation devices can increase anammox levels in such systems.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Yijing
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; Northwestern University, Department of Civil and Environmental Engineering, Evanston, IL, USA. Electronic address: george.wells@northwestern.edu.
authors.forename: George
authors.initials: G
authors.lastname: Wells
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; ETH Zurich, Institute of Environmental Engineering, 8093 Zurich, Switzerland.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Morgenroth
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry / Q000378:metabolism*; D020562:Betaproteobacteria / Q000254:growth & development / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D011232:Chemical Precipitation; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*
chemical_list: D064751:Ammonium Compounds; D009573:Nitrites; D012722:Sewage
keywords: AOB; Anammox; Flocs; Granular sludge; Hydrocyclone