Sulfate Reduction at pH 4 During the Thermophilic (55 degrees C) Acidification of Sucrose in UASB Reactors

S.I.C. Lopes, M.I. Capela, S.A. Dar, G. Muyzer, P.N.L. Lens

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)

Abstract

Continuous sulfate reduction at pH 4.0 was demonstrated in a pH controlled thermophilic (55 degrees C) upflow anaerobic sludge bed reactor fed with sucrose at a COD/SO42- ratio of 0.9 and an organic loading rate of 0.8 and 1.9 gCOD (l(reactor) d)(-1) for a period of 78 days. A near v complete sulfate reduction efficiency was achieved throughout the reactor run, corresponding to sulfate removal rates of 0.91 and 1.92 g (l(reactor) d)(-1) at sulfate loading rates of 0.94 and 2 g (l(reactor) d)(-1), respectively, by keeping the sulfide concentration below 20 mg l(-1) due to stripping with nitrogen gas. Acidification was always complete and acetate was the only, degradation intermediate left in the effluent, which did not exceed 180 mgCOD l(-1) in pseudo-stationary states. The sludge was well retained ill the reactor and kept its granular form. A, Cu, Se, and Mo accumulated in the sludge, whereas Co, Ni, Fe, and Mn leached from the sludge, despite their continuous supply to the reactor via the influent. The bacterial diversity in the reactor sludge at the end of the reactor run was low and the culture was dominated by one acidifying species, resembling Thermoanaerobacterium sp., and one sulfate reducing species, resembling Desulfotomaculum sp.
Original languageEnglish
Pages (from-to)1278-1289
JournalBiotechnology Progress
Volume24
Issue number6
DOIs
Publication statusPublished - 2008

Keywords

  • acid-mine drainage
  • gradient gel-electrophoresis
  • anaerobic granular sludge
  • in-situ hybridization
  • mill waste-water
  • sp-nov
  • reducing bacterium
  • metal fractionation
  • bioreactor
  • sulfur

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