title: Selection of denitrifying phosphorous accumulating organisms in IFAS systems: comparison of nitrite with nitrate as an electron acceptor.
abstract: Nitrite and nitrate were compared as electron acceptors to select for denitrifying phosphorous accumulating organisms (DPAO) in two integrated fixed film activated sludge (IFAS 1 and IFAS 2) systems operated as sequencing batch reactors. The bench-scale experiment lasted one year and synthetic wastewater was used as feed. During anoxic conditions 20mgNO3(-)-NL(-1) were dosed into IFAS-1 and 20mgNO2(-)-NL(-1) were dosed into IFAS-2. Long term phosphorous and ammonia removal via nitritation were achieved in both systems and both attached and suspended biomass contributed to phosphorous and ammonia removal. DPAO showed no specific adaptation to the electron acceptor as evidenced by short term switch of feeding with nitrate or nitrite. Anoxic phosphorus uptake rate was significantly higher with nitrite than with nitrate. Results showed that DPAO activity with nitrite could be integrated into attached and suspended biomass of IFAS systems in long term operation.
authors.affiliation: Department of Civil Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada. Electronic address: umjabari@cc.umanitoba.ca.
authors.forename: Pouria
authors.initials: P
authors.lastname: Jabari
authors.affiliation: Department of Civil Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada; Department of Civil and Environmental Engineering, University of Florence, Via S. Marta 3, 50139 Florence, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Munz
authors.affiliation: Department of Civil Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Oleszkiewicz
mesh_terms: D000641:Ammonia / Q000737:chemistry / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D018533:Biomass; D019149:Bioreactors; D058440:Denitrification; D004583:Electrons; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism*; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D010758:Phosphorus / Q000737:chemistry / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D010758:Phosphorus; D000641:Ammonia
keywords: Attached biomass; Denitrifying phosphorous accumulating organisms (DPAO); Integrated fixed-film activated sludge systems (IFAS); Nitrite