title: Bacterial community involved in the nitrogen cycle in a down-flow sponge-based trickling filter treating UASB effluent.
abstract: The bacterial community composition of a down-flow sponge-based trickling filter treating upflow anaerobic sludge blanket (UASB) effluent was investigated by pyrosequencing. Bacterial community composition considerably changed along the reactor and over the operational period. The dominant phyla detected were Proteobacteria, Verrucomicrobia, and Planctomycetes. The abundance of denitrifiers decreased from the top to the bottom and it was consistent with the organic matter concentration gradients. At lower loadings (organic and nitrogen loading rates), the abundance of anammox bacteria was higher than that of the ammonium-oxidizing bacteria in the upper portion of the reactor, suggesting that aerobic and anaerobic ammonium oxidation occurred. Nitrification occurred in all the compartments, while anammox bacteria prominently appeared even in the presence of high organic carbon to ammonia ratios (around 1.0-2.0 gCOD gN(-1)). The results suggest that denitrifiers, nitrifiers, and anammox bacteria coexisted in the reactor; thus, different metabolic pathways were involved in ammonium removal in the post-UASB reactor sponge-based.
authors.affiliation: Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, Minas Gerais, Brazil E-mail: erikafabreu@yahoo.com.br.
authors.forename: E F A
authors.initials: EF
authors.lastname: Mac Conell
authors.affiliation: Environmental Engineering and Water Technology Department, UNESCO-IHE, Westvest 7, 2611 AX, Delft, The Netherlands.
authors.forename: P G S
authors.initials: PG
authors.lastname: Almeida
authors.affiliation: Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, Minas Gerais, Brazil E-mail: erikafabreu@yahoo.com.br.
authors.forename: K E L
authors.initials: KE
authors.lastname: Martins
authors.affiliation: Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, Minas Gerais, Brazil E-mail: erikafabreu@yahoo.com.br.
authors.forename: J C
authors.initials: JC
authors.lastname: Araújo
authors.affiliation: Department of Sanitary and Environmental Engineering, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, Minas Gerais, Brazil E-mail: erikafabreu@yahoo.com.br.
authors.forename: C A L
authors.initials: CA
authors.lastname: Chernicharo
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D019149:Bioreactors / Q000382:microbiology; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D058458:Nitrogen Cycle; D011161:Porifera / Q000382:microbiology*; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods
chemical_list: D012722:Sewage; D000641:Ammonia; D009584:Nitrogen