title: The behavior of nitrifying sludge in presence of sulfur compounds using a floating biofilm reactor.
abstract: The tolerance, kinetic and oxidizing capability of a nitrifying sludge exposed to different initial concentrations of sulfide (1.7 to 18mg/L) was evaluated in batch experiments. A nitrifying sludge fed with ammonium and thiosulfate and produced in steady state conditions was used as inoculum. Sulfide induced a significant effect either on ammonium consumption rates or nitrite accumulation. In spite of the nitrifying kinetic was affected, the ammonium consumption efficiencies were close to 100%, with nitrate production yields around 1.0. The IC(50) value for ammonium oxidizing-process was 13mg/L of sulfide. Sulfide was oxidized in two steps: first sulfide was oxidized to elemental sulfur and afterward into sulfate. FISH oligonucleotide probes for Thiobacillusdenitrificans, Nitrosomonas spp., and Nitrobacter spp. were used in order to know if these bacteria were part of the microbial ecology. The obtained results showed that under nitrifying conditions are possible to carry out simultaneously two biological processes, nitrification and sulfur oxidation.
authors.affiliation: University of Santiago de Compostela, Department of Chemical Engineering, Rua Lope Gómez de Marzoa, Santiago de Compostela, Spain. beristain_3@yahoo.com.mx
authors.forename: Ricardo
authors.initials: R
authors.lastname: Beristain-Cardoso
authors.forename: Jorge
authors.initials: J
authors.lastname: Gómez
authors.forename: Ramón
authors.initials: R
authors.lastname: Méndez-Pampín
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013457:Sulfur Compounds / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000644:Quaternary Ammonium Compounds; D012722:Sewage; D013457:Sulfur Compounds