Characterization and kinetics of sulfide-oxidizing autotrophic denitrification in batch reactors containing suspended and immobilized cells

摘要

Sulfide-oxidizing autotrophic denitrification is an advantageous alternative over heterotrophicndenitrification, and may have potential for nitrogen removal of low-strength wastewaters, such asnanaerobically pre-treated domestic sewage. This study evaluated the fundamentals and kinetics ofnthis process in batch reactors containing suspended and immobilized cells. Batch tests werenperformed for different NOxnu0001/S2u0001 ratios and using nitrate and nitrite as electron acceptors.nAutotrophic denitrification was observed for both electron acceptors, and NOxnu0001/S2u0001 ratios definednwhether sulfide oxidation was complete or not. Kinetic parameter values obtained for nitrate werenhigher than for nitrite as electron acceptor. Zero-order models were better adjusted to profilesnobtained for suspended cell reactors, whereas first-order models were more adequate fornimmobilized cell reactors. However, in the latter, mass transfer physical phenomena had a significantneffect on kinetics based on biochemical reactions. Results showed that sulfide-oxidizing autotrophicndenitrification can be successfully established for low-strength wastewaters and have potential fornnitrogen removal from anaerobically pre-treated domestic sewage.