title: Characterization and kinetics of sulfide-oxidizing autotrophic denitrification in batch reactors containing suspended and immobilized cells.
abstract: Sulfide-oxidizing autotrophic denitrification is an advantageous alternative over heterotrophic denitrification, and may have potential for nitrogen removal of low-strength wastewaters, such as anaerobically pre-treated domestic sewage. This study evaluated the fundamentals and kinetics of this process in batch reactors containing suspended and immobilized cells. Batch tests were performed for different NOx-/S2- ratios and using nitrate and nitrite as electron acceptors. Autotrophic denitrification was observed for both electron acceptors, and NOx-/S2- ratios defined whether sulfide oxidation was complete or not. Kinetic parameter values obtained for nitrate were higher than for nitrite as electron acceptor. Zero-order models were better adjusted to profiles obtained for suspended cell reactors, whereas first-order models were more adequate for immobilized cell reactors. However, in the latter, mass transfer physical phenomena had a significant effect on kinetics based on biochemical reactions. Results showed that sulfide-oxidizing autotrophic denitrification can be successfully established for low-strength wastewaters and have potential for nitrogen removal from anaerobically pre-treated domestic sewage.
authors.affiliation: Departamento de Hidráulica e Saneamento, Escola de Engenharia de São Carlos, Universidade de São Paulo, AV. Trabalhador São-Carlense, 400, Centro, 13566-590, Sāo Carlos, SP, Brazil. bs_moraes@yahoo.com.br
authors.forename: B S
authors.initials: BS
authors.lastname: Moraes
authors.forename: T S O
authors.initials: TS
authors.lastname: Souza
authors.forename: E
authors.initials: E
authors.lastname: Foresti
mesh_terms: D019149:Bioreactors; D058440:Denitrification; D007700:Kinetics; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry*
chemical_list: D013440:Sulfides