title: Influence of COD/N ratio and carbon source on nitrogen removal in a structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA).
abstract: This study aimed to evaluate the influence of COD/N ratio and carbon source on simultaneous nitrogen and carbon removal processes. A continuous up-flow structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) was operated with hydraulic retention time (HRT) of 11.2 ± 0.6 h. The carbon sources were meat peptone and sucrose. The COD/N ratio varied by maintaining the organic loading rate fixed at 1.07 kg COD m(-3) d(-1) and changing the total-N concentration. The COD/N ratios tested were 9.7 ± 1 (sucrose); 7.6 ± 1 (meat peptone); 2.9 ± 1 (meat peptone) and 2.9 ± 0.4 (sucrose). COD removal efficiencies remained above 90% in all experimental phases. At lower COD/N ratios, NH4(+)-N oxidation efficiencies were higher than 90%. An autotrophic metabolism by anammox process was observed in Phases III and IV, which was responsible for 35% and 27% of total-N loading removal rates, respectively. Therefore, the system achieved total nitrogen removal efficiencies of 84.6 ± 10.1 and 81.5 ± 5.3%, under low availability of organic electron donors.
authors.affiliation: Laboratory of Biological Processes, Center for Research, Development and Innovations in Environmental Engineering, School of Engineering of São Carlos, University of São Paulo, Av. João Dagnone 1100, São Carlos, SP, 13563-120, Brazil. Electronic address: c.diniz@ymail.com.
authors.forename: Carla E D
authors.initials: CE
authors.lastname: Santos
authors.affiliation: Institute of Science and Technology, Federal University of Alfenas, Rod. José Aurélio Vilela, Cidade Universitária, 37715-400, Poços de Caldas, MG, Brazil. Electronic address: rafael.moura@unifal-mg.edu.br.
authors.forename: Rafael B
authors.initials: RB
authors.lastname: Moura
authors.affiliation: Laboratory of Biological Processes, Center for Research, Development and Innovations in Environmental Engineering, School of Engineering of São Carlos, University of São Paulo, Av. João Dagnone 1100, São Carlos, SP, 13563-120, Brazil. Electronic address: mdamianovic@sc.usp.br.
authors.forename: Márcia H R Z
authors.initials: MH
authors.lastname: Damianovic
authors.affiliation: Laboratory of Biological Processes, Center for Research, Development and Innovations in Environmental Engineering, School of Engineering of São Carlos, University of São Paulo, Av. João Dagnone 1100, São Carlos, SP, 13563-120, Brazil. Electronic address: eforesti@sc.usp.br.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Foresti
mesh_terms: D052818:Autotrophic Processes; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D058440:Denitrification; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D010084:Oxidation-Reduction; D018508:Water Purification / Q000379:methods
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Anammox; COD/N ratio; Simultaneous nitrification denitrification (SND); Structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA)