Laboratory-scale bioreactors for soluble selenium removal from selenium refinery wastewater using anaerobic sludge

Satoshi Soda, Masami Kashiwa, Tsubasa Kagami, Masashi Kuroda, Mitsuo Yamashita, Michihiko Ike

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Laboratory-scale bioreactors were constructed to investigate their applicability for recovery of soluble selenium from industrial wastewater. Microbial reduction of soluble selenium into elemental selenium is the key reaction because, as a result of its insoluble characteristics, it can be removed easily from the aqueous phase. Wastewater of a selenium refinery plant showed extremely low pH (<1.0), high salinity (6-7%), and various selenium concentrations (mainly selenite, 13.2-74.0mgl-1). As preconditioning for microbial reduction, the wastewater pH and salinity were adjusted, respectively, to about 7.5 and 1.1%. Granular sludge of an up-flow anaerobic sludge blanket (UASB) reactor and suspended sludge of a sewage sludge digester were seeded respectively to a UASB-type reactor and a suspended sludge bed reactor. The 2.2-l bioreactors were operated at 30°C and hydraulic retention time of about 24h for preconditioned wastewater supplemented with ethanol as a carbon source. The removal of 1.5-3.5mgl-1 soluble selenium was only 60% in the swim-bed reactor. The selenium concentration in effluent of the UASB-type reactor dropped to less than the regulated amount of the effluent concentration of selenium of 0.1mgl-1 by day 15.

Original languageEnglish
Pages (from-to)433-438
Number of pages6
JournalDesalination
Volume279
Issue number1-3
DOIs
Publication statusPublished - 2011 Sep 15

Keywords

  • Anaerobic sludge
  • Metal refinery wastewater
  • Selenium
  • UASB reactor

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Water Science and Technology
  • Mechanical Engineering

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