title: Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors.
abstract: The present paper reports the results of a nitrous oxide (N2O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N2O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N2O was, however, also found in the anaerobic reactor, thus indicating a probable occurrence of the denitrifying phosphate accumulating organism activity. The highest N2O fluxes were emitted from the aerated reactors (3.09 g N2ON m-2h-1and 9.87 g N2ON m-2h-1, aerobic and MBR tank, respectively). The emission factor highlighted that only 1% of the total treated nitrogen was emitted from the pilot plant. Furthermore, the measured N2O concentrations in the permeate flow were comparable with other reactors. Nitrous oxide mass balances outlined a moderate production also in the MBR reactor despite the low hydraulic retention time. On the other hand, the mass balance showed that in the aerobic reactor a constant consumption of nitrous oxide (up to almost 15 mg N2O h-1) took place, due to the high amount of stripped gas.
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, Ed. 8, 90100, Palermo, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Mannina
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, Ed. 8, 90100, Palermo, Italy. Electronic address: marco.capodici@unipa.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Capodici
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, Ed. 8, 90100, Palermo, Italy.
authors.forename: Alida
authors.initials: A
authors.lastname: Cosenza
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, Ed. 8, 90100, Palermo, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Di Trapani
authors.affiliation: Dipartimento di Scienze Agrarie e Forestali, Università di Palermo, Viale delle Scienze, Ed. 4, 90128, Palermo, Italy.
authors.forename: Vito Armando
authors.initials: VA
authors.lastname: Laudicina
authors.affiliation: Norwegian University of Science and Technology, Department of Hydraulic and Environmental Engineering, 7491 Trondheim, Norway.
authors.forename: Hallvard
authors.initials: H
authors.lastname: Ødegaard
mesh_terms: D019149:Bioreactors; D058440:Denitrification; D005740:Gases / Q000032:analysis; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism; D009609:Nitrous Oxide / Q000032:analysis* / Q000378:metabolism; D010758:Phosphorus / Q000302:isolation & purification; D010865:Pilot Projects; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods
chemical_list: D005740:Gases; D012722:Sewage; D010758:Phosphorus; D009609:Nitrous Oxide; D009584:Nitrogen
keywords: Emission factor; IFAS; MBR; Nitrous oxide; UCT