title: Understanding the contribution of biofilm in an integrated fixed-film-activated sludge system (IFAS) designed for nitrogen removal.
abstract: The objective of this study is to improve knowledge on the integrated fixed-film-activated sludge (IFAS) system designed for nitrogen removal. Biofilm growth and its contribution to nitrification were monitored under various operating conditions in a semi-industrial pilot-scale plant. Nitrification rates were observed in biofilms developed on free-floating media and in activated sludge operated under a low sludge retention time (4 days) and at an ammonia loading rate of 45-70 gNH4-N/kgMLVSS/d. Operational conditions, i.e. oxygen concentration, redox potential, suspended solids concentration, ammonium and nitrates, were monitored continuously in the reactors. High removal efficiencies were observed for carbon and ammonium at high-loading rate. The contribution of biofilm to nitrification was determined as 40-70% of total NOx-N production under the operating conditions tested. Optimal conditions to optimize process compacity were determined. The tested configuration responds especially well to winter and summer nitrification conditions. These results help provide a deeper understanding of how autotrophic biomass evolves through environmental and operational conditions in IFAS systems.
authors.affiliation: Irstea, UR MALY, 5 rue de la Doua CS70077, 69626 Villeurbanne, France E-mail: jean-marc.choubert@irstea.fr.
authors.forename: P
authors.initials: P
authors.lastname: Moretti
authors.affiliation: Irstea, UR MALY, 5 rue de la Doua CS70077, 69626 Villeurbanne, France E-mail: jean-marc.choubert@irstea.fr.
authors.forename: J M
authors.initials: JM
authors.lastname: Choubert
authors.affiliation: Irstea, UR MALY, 5 rue de la Doua CS70077, 69626 Villeurbanne, France E-mail: jean-marc.choubert@irstea.fr.
authors.forename: J P
authors.initials: JP
authors.lastname: Canler
authors.affiliation: Vinci Environnement France SA, 89 Boulevard Franklin Roosevelt, 92506 Rueil-Malmaison Cedex, France.
authors.forename: O
authors.initials: O
authors.lastname: Petrimaux
authors.affiliation: Laboratoire de Génie Civil et d'Ingénierie Environnementale, Université de Lyon, INSA de Lyon, 69621 Villeurbanne, France.
authors.forename: P
authors.initials: P
authors.lastname: Buffiere
authors.affiliation: Département de Génie Civil et de Génie des Eaux, Pavillon Adrien-Pouliot, Université Laval Québec (Qc), Canada G1V0A6.
authors.forename: P
authors.initials: P
authors.lastname: Lessard
mesh_terms: D000641:Ammonia / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D018533:Biomass; D058440:Denitrification; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*
chemical_list: D064751:Ammonium Compounds; D012722:Sewage; D000641:Ammonia; D009584:Nitrogen