title: Fluidized-bed denitrification of mining water tolerates high nickel concentrations.
abstract: This study revealed that fluidized-bed denitrifying cultures tolerated soluble Ni concentrations up to 500 mg/L at 7-8 and 22°C. From 10 to 40 mg/L of feed Ni, denitrification resulted in complete nitrate and nitrite removal. The concomitant reduction of 30 mg/L of sulfate produced 10 mg/L of sulfide that precipitated nickel, resulting in soluble effluent Ni below 22 mg/L. At this stage, Dechloromonas species were the dominant denitrifying bacteria. From 60 to 500 mg/L of feed Ni, nickel remained in solution due to the inhibition of sulfate reduction. At soluble 60 mg/L of Ni, denitrification was partially inhibited prior to recover after 34 days of enrichment by other Ni-tolerant species (including Delftia, Zoogloea and Azospira) that supported Dechloromonas. Subsequently, the FBR cultures completely removed nitrate even at 500 mg/L of Ni. Visual Minteq speciation model predicted the formation of NiS, NiCO3 and Ni3(PO4)2, whilst only Ni3(PO4)2 was detected by XRD.
authors.affiliation: Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland. Electronic address: gang.zou@tut.fi.
authors.forename: G
authors.initials: G
authors.lastname: Zou
authors.affiliation: Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Papirio
authors.affiliation: Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454 Marne-la-Vallée, France.
authors.forename: E D
authors.initials: ED
authors.lastname: van Hullebusch
authors.affiliation: Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland.
authors.forename: J A
authors.initials: JA
authors.lastname: Puhakka
mesh_terms: D001419:Bacteria / Q000378:metabolism; D018533:Biomass; D019149:Bioreactors; D002606:Charcoal / Q000737:chemistry; D011232:Chemical Precipitation; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D008903:Minerals / Q000032:analysis; D008906:Mining; D008962:Models, Theoretical; D009532:Nickel / Q000032:analysis*; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013054:Spectrophotometry, Atomic; D014865:Waste Disposal, Fluid; D014867:Water / Q000737:chemistry*; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D008903:Minerals; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; D014867:Water; D002606:Charcoal; D009532:Nickel
keywords: Denitrification; Denitrifying communities; Fluidized-bed reactor; Nickel; X-ray diffraction