Biological perchlorate reduction in packed bed reactors using elemental sulfur

Environ Sci Technol. 2009 Jun 15;43(12):4466-71. doi: 10.1021/es900563f.


Sulfur-utilizing perchlorate (ClO4-)-reducing bacteria were enriched from a denitrifying wastewater seed with elemental sulfur (S0) as an electron donor. The enrichment was composed of a diverse microbial community, with the majority identified as members of the phylum Proteobacteria. Cultures were inoculated into bench-scale packed bed reactors (PBR) with S0 and crushed oyster shell packing media. High ClO4-concentrations (5-8 mg/L) were reduced to < 0.5 mg/L at an empty bed contact time (EBCT) of 13 h. Low C1O4- concentrations (60-120 microg/L), more typical of contaminated groundwater sites, were reduced to < 4 microg/L at an EBCT of 7.5 h. PBR performance decreased when effluent recirculation was applied or when smaller S0 particle sizes were used, indicating that mass transfer of ClO4- to the attached biofilm was not the limiting mechanism in this process, and that biofilm acclimation and growth were key factors in overall reactor performance. The presence of nitrate (6.5 mg N/L) inhibited ClO4- reduction. The microbial community composition was found to change with ClO4- availability from a majority of Beta-Proteobacteria near the influent end of the reactor to primarily sulfur-oxidizing bacteria near the effluent end of the reactor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria / metabolism*
  • Bioreactors
  • Environmental Pollutants / chemistry
  • Environmental Pollutants / metabolism
  • Medical Waste Disposal
  • Oxidation-Reduction
  • Perchlorates / chemistry
  • Perchlorates / metabolism*
  • Sulfur / chemistry*


  • Environmental Pollutants
  • Medical Waste Disposal
  • Perchlorates
  • Sulfur
  • perchlorate