title: Effect of process parameters and operational mode on nitrous oxide emissions from a nitritation reactor treating reject wastewater.
abstract: Nitrous oxide (N2O) and methane emissions were monitored in a continuous granular airlift nitritation reactor from ammonium-rich wastewater (reject wastewater). N2O emissions were found to be dependent on dissolved oxygen (DO) concentration in the range of 1-4.5 mg O2/L, increasing within this range when reducing the DO values. At higher DO concentrations, N2O emissions remained constant at 2.2% of the N oxidized to nitrite, suggesting two different mechanisms behind N2O production, one dependent and one independent of DO concentration. Changes on ammonium, nitrite, free ammonia and free nitrous acid concentrations did not have an effect on N2O emissions within the concentration range tested. When operating the reactor in a sequencing batch mode under high DO concentration (>5 mg O2/L), N2O emissions increased one order of magnitude reaching values of 19.3 ± 7.5% of the N oxidized. Moreover, CH4 emissions detected were due to the stripping of the soluble CH4 that remained dissolved in the reject wastewater after anaerobic digestion. Finally, an economical and carbon footprint assessment of a theoretical scaled up of the pilot plant was conducted.
authors: Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, 17003 Girona, Spain. Electronic address: mpijuan@icra.cat.
authors: Maite
authors: M
authors: Pijuan
authors: Department of Chemical Engineering, School of Engineering, Universitat Autònoma de Barcelona, Spain.
authors: Josep
authors: J
authors: Torà
authors: Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, 17003 Girona, Spain.
authors: Adrián
authors: A
authors: Rodríguez-Caballero
authors: Depuración de Aguas del Mediterráneo (DAM), Guglielmo Marconi, 11 piso 2°, despacho 19, Parque Tecnológico, 46980 Paterna, Valencia, Spain.
authors: Elvira
authors: E
authors: César
authors: Department of Chemical Engineering, School of Engineering, Universitat Autònoma de Barcelona, Spain.
authors: Julián
authors: J
authors: Carrera
authors: Department of Chemical Engineering, School of Engineering, Universitat Autònoma de Barcelona, Spain.
authors: Julio
authors: J
authors: Pérez
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000191:economics; D000397:Air Pollution / Q000191:economics / Q000517:prevention & control; D064751:Ammonium Compounds / Q000032:analysis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002244:Carbon / Q000032:analysis; D008697:Methane / Q000032:analysis; D058465:Nitrification; D009573:Nitrites / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D009609:Nitrous Oxide / Q000032:analysis*; D010100:Oxygen / Q000032:analysis; D010865:Pilot Projects; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000191:economics / Q000379:methods*
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D002244:Carbon; D008697:Methane; D009573:Nitrites; D009584:Nitrogen; D009609:Nitrous Oxide; D010100:Oxygen; D062065:Wastewater
keywords: Continuous vs discontinuous operation; Economical analysis; Nitrous oxide emissions; Partial nitrification; Reject wastewater