title: Kinetics and stoichiometry of sulfide oxidation by sewer biofilms.
abstract: Oxidation of sulfide under aerobic conditions by biofilms grown on municipal wastewater in 6 identical pipe reactors was investigated. The biofilms were grown at pH 7.6 and temperatures of 20 and 25 degrees C under aerobic-anaerobic transient conditions with pulse dosing of sulfide in the bulk water. The pulse dosing of sulfide served to simulate conditions in a gravity sewer located downstream of a pressure main. During growth of the biofilms, sulfide was pulse dosed in concentrations of 0, 0.5, 2.0 and 5.0 g Sm(-3) with a frequency of 1h(-1). Based on a series of batch experiments, kinetics and stoichiometry of sulfide oxidation by the sewer biofilms was investigated and a rate equation and a stoichiometric constant proposed. Sulfide oxidation kinetics was significantly faster for biofilms grown at sulfide loadings of 0.5, 2.0 and 5.0 g Sm(-3)h(-1) than for biofilms grown in the absence of sulfide. However, the kinetics of sulfide oxidation was relatively constant for biofilms grown at sulfide loadings above 0.5 g Sm(-3)h(-1). Mass balance calculations of dissolved oxygen and sulfur compounds suggested the oxidation product to be elemental sulfur. Further oxidation of elemental sulfur could not be documented.
authors.affiliation: Section of Environmental Engineering, Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark. ahn@bio.aau.dk
authors.forename: Asbjørn Haaning
authors.initials: AH
authors.lastname: Nielsen
authors.forename: Thorkild
authors.initials: T
authors.lastname: Hvitved-Jacobsen
authors.forename: Jes
authors.initials: J
authors.lastname: Vollertsen
mesh_terms: D018441:Biofilms; D007700:Kinetics; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry*
chemical_list: D013440:Sulfides