title: Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.
abstract: The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product.
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CCT - La Plata - CONICET, Facultad de Ciencias Exactas, UNLP, 47 y 116, B1900AJJ La Plata, Argentina. Electronic address: ing.juankal@yahoo.es.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Alzate Marin
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CCT - La Plata - CONICET, Facultad de Ciencias Exactas, UNLP, 47 y 116, B1900AJJ La Plata, Argentina.
authors.forename: Alejandro H
authors.initials: AH
authors.lastname: Caravelli
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CCT - La Plata - CONICET, Facultad de Ciencias Exactas, UNLP, 47 y 116, B1900AJJ La Plata, Argentina; Facultad de Ingeniería, UNLP, 48 y 115, B1900AJJ La Plata, Argentina.
authors.forename: Noemí E
authors.initials: NE
authors.lastname: Zaritzky
mesh_terms: D019149:Bioreactors; D058440:Denitrification; D004867:Equipment Design; D005740:Gases; D006003:Glycogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D058465:Nitrification; D009584:Nitrogen / Q000737:chemistry; D009609:Nitrous Oxide / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010641:Phenotype; D010758:Phosphorus / Q000737:chemistry; D062065:Wastewater
chemical_list: D005740:Gases; D006003:Glycogen; D009584:Nitrogen; D009609:Nitrous Oxide; D010100:Oxygen; D010758:Phosphorus; D062065:Wastewater
keywords: Activated sludge; Denitrification; Nitrification; Nitrogen; Sequencing batch reactor