Biological perchlorate reduction in packed bed reactors using elemental sulfur.

TitleBiological perchlorate reduction in packed bed reactors using elemental sulfur.
Publication TypeJournal Article
Year of Publication2009
AuthorsSahu AK, Conneely T, Nüsslein KR, Ergas SJ
JournalEnviron Sci Technol
Date Published2009 Jun 15
KeywordsBacteria, Bioreactors, Environmental Pollutants, Medical Waste Disposal, Oxidation-Reduction, Perchloric Acid, Sulfur

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.

Alternate JournalEnviron. Sci. Technol.
PubMed ID19603663