Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

Denys Kristalia Villa-Gómez, Anne Marie Enright, Eki Listya Rini, Audrey L. Buttice, Herman J M Kramer, Piet Nl L Lens

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


BACKGROUND: Metal sulfide recovery in sulfate reducing bioreactors is a challenge due to the formation of small precipitates with poor settling properties. The size of the metal sulfide precipitates with the change in operational parameters such as pH, sulfide concentration and reactor configuration has been previously studied. The effect of the hydraulic retention time (HRT) on the metal precipitate characteristics such as particle size for settling has not yet been addressed. RESULTS: The change in size of the metal (Cu, Zn, Pb and Cd) sulfide precipitates as a function of the HRT was studied in two sulfate reducing inversed fluidized bed (IFB) reactors operating at different chemical oxygen demand concentrations to produce high and low sulfide concentrations. The decrease of the HRT from 24 to 9h in both IFB reactors affected the contact time of the precipitates formed, thus making differences in aggregation and particle growth regardless of the differences in sulfide concentration. Further HRT decrease to 4.5h affected the sulfate reducing activity for sulfide production and hence, the supersaturation level and solid phase speciation. Metal sulfide precipitates affected the sulfate reducing activity and community in the biofilm, probably because of the stronger local supersaturation causing metal sulfides accumulation in the biofilm. CONCLUSIONS: This study shows that the HRT is an important factor determining the size and thus the settling rate of the metal sulfides formed in bioreactors.
Original languageEnglish (US)
Pages (from-to)120-129
Number of pages10
JournalJournal of Chemical Technology & Biotechnology
Issue number1
StatePublished - Feb 13 2014

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research was supported financially by the National Council for Science and Technology, Mexico (CONACYT-192635). The authors would like to thank the laboratory staff (UNESCO-IHE), the Microbial Ecology Laboratory (National University of Ireland) and the Laboratory of Process and Energy (TU Delft) for the analytical support.

ASJC Scopus subject areas

  • Organic Chemistry
  • General Chemical Engineering
  • Pollution
  • Biotechnology
  • Inorganic Chemistry
  • Waste Management and Disposal
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment


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