title: Effect of HCO3- concentration on anammox nitrogen removal rate in a moving bed biofilm reactor.
abstract: Anammox biomass enriched in a moving bed biofilm reactor (MBBR) fed by actual sewage sludge reject water and synthetically added NO2- was used to study the total nitrogen (TN) removal rate of the anammox process depending on bicarbonate (HCO3-) concentration. MBBR performance resulted in the maximum TN removal rate of 1100 g N m(-3) d(-1) when the optimum HCO3- concentration (910 mg L(-1)) was used. The average reaction ratio of NO2- removal, NO3- production and NH4+ removal were 1.18/0.20/1. When the HCO3- concentration was increased to 1760mg L(-1) the TN removal rate diminished to 270 g N m(-3) d(-1). The process recovered from bicarbonate inhibition within 1 week. The batch tests performed with biomass taken from the MBBR showed that for the HCO3- concentration of 615 mg L(-1) the TN removal rate was 3.3 mg N L(-1) h(-1), whereas for both lower (120 mg L(-1)) and higher (5750 mg L(-1)) HCO3- concentrations the TN removal rates were 2.3 (+/- 0.15) and 1.6 (+/- 0.12) mg N L(-1) d(-1), respectively. PCR and DGGE analyses resulted in the detection of uncultured Planctomycetales bacterium clone P4 and, surprisingly, low-oxygen-tolerant aerobic ammonia oxidizers. The ability of anammox bacteria for mixotrophy was established by diminished amounts of nitrate produced when comparing the experiments with an organic carbon source and an inorganic carbon source.
authors: Institute of Chemistry, University of Tartu, Tartu, Estonia. ivar.zekker@ut.ee
authors: Ivar
authors: I
authors: Zekker
authors: Ergo
authors: E
authors: Rikmann
authors: Toomas
authors: T
authors: Tenno
authors: Priit
authors: P
authors: Vabamäe
authors: Kristel
authors: K
authors: Kroon
authors: Liis
authors: L
authors: Loorits
authors: Alar
authors: A
authors: Saluste
authors: Taavo
authors: T
authors: Tenno
mesh_terms: D000693:Anaerobiosis; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology; D002255:Carbonic Acid / Q000737:chemistry*; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification; D009584:Nitrogen / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D018508:Water Purification
chemical_list: D000644:Quaternary Ammonium Compounds; D002255:Carbonic Acid; D009584:Nitrogen