title: Removal of ammonium via simultaneous nitrification-denitrification nitrite-shortcut in a single packed-bed batch reactor.
abstract: A polyurethane packed-bed-biofilm sequential batch reactor was fed with synthetic substrate simulating the composition of UASB reactor effluents. Two distinct ammonia nitrogen concentrations (125 and 250 mg l(-1)) were supplied during two sequential long-term experiments of 160 days each (320 total). Cycles of 24h under intermittent aeration for periods of 1h were applied, and ethanol was added as a carbon source at the beginning of each anoxic period. Nitrite was the main oxidized nitrogen compound which accumulated only during the aerated phases of the batch cycle. A consistent decrease of nitrite concentration started always immediately after the interruption of oxygen supply and addition of the electron donor. Removal to below detection limits of all nitrogen soluble forms was always observed at the end of the 24h cycles for both initial concentrations. Polyurethane packed-bed matrices and ethanol amendments conferred high process stability. Microbial investigation by cloning suggested that nitrification was carried out by Nitrosomonas-like species whereas denitrification was mediated by unclassified species commonly observed in denitrifying environments. The packed-bed batch bioreactor favored the simultaneous colonization of distinct microbial groups within the immobilized microbial biomass. The biofilm was capable of actively oxidizing ammonium and denitrification at high ratios in intermittent intervals within 24h cycles.
authors.affiliation: Departmento of Hidráulica e Saneamento, Escola de Engenharia e São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
authors.forename: Leonidia Maria Castro
authors.initials: LM
authors.lastname: Daniel
authors.forename: Eloísa
authors.initials: E
authors.lastname: Pozzi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Foresti
authors.forename: Fabio Alexandre
authors.initials: FA
authors.lastname: Chinalia
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D009566:Nitrates / Q000302:isolation & purification / Q000378:metabolism*; D009573:Nitrites / Q000302:isolation & purification / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000302:isolation & purification / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D009566:Nitrates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical