@article {735,
	title = {Biological perchlorate reduction in packed bed reactors using elemental sulfur.},
	journal = {Environ Sci Technol},
	volume = {43},
	year = {2009},
	month = {2009 Jun 15},
	pages = {4466-71},
	abstract = {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.},
	keywords = {Bacteria, Bioreactors, Environmental Pollutants, Medical Waste Disposal, Oxidation-Reduction, Perchloric Acid, Sulfur},
	issn = {0013-936X},
	author = {Sahu, Ashish K and Conneely, Teresa and N{\"u}sslein, Klaus R and Ergas, Sarina J}
}
@article {736,
	title = {Hydrogenotrophic denitrification and perchlorate reduction in ion exchange brines using membrane biofilm reactors.},
	journal = {Biotechnol Bioeng},
	volume = {104},
	year = {2009},
	month = {2009 Oct 15},
	pages = {483-91},
	abstract = {Halophilic (salt loving), hydrogenotrophic (H(2) oxidizing) denitrifying bacteria were investigated for treatment of nitrate (NO3-) and perchlorate (ClO4-) contaminated groundwater and ion exchange (IX) brines. Hydrogenotrophic denitrifying bacteria were enriched from a denitrifying wastewater seed under both halophilc and non-halophilc conditions. The cultures were inoculated into bench-scale membrane biofilm reactors (MBfRs) with an "outside in" configuration, with contaminated water supplied to the lumen of the membranes and H(2) supplied to the shell. Abiotic mass transfer tests showed that H(2) mass transfer coefficients were lower in brines than in tap water at highest Reynolds number, possibly due to increased transport of salts and decreased H(2) solubility at the membrane/liquid interface. An average NO3- removal efficiency of 93\% was observed for the MBfR operated in continuous flow mode with synthetic contaminated groundwater. Removal efficiencies of 30\% for NO3- and 42\% for ClO4- were observed for the MBfR operated with synthetic IX brine in batch operating mode with a reaction time of 53 h. Phylogenetic analysis focused on the active microbial community and revealed that halotolerant, NO3- -reducing bacteria of the bacterial classes Gamma-Proteobacteria and Sphingobacteria were the metabolically dominant members within the stabilized biofilm. This study shows that, despite decreased H(2) transfer under high salt conditions, hydrogenotrophic biological reduction may be successfully used for the treatment of NO3- and ClO- in a MBfR.},
	keywords = {Bacteroidetes, Biofilms, Cluster Analysis, DNA, Bacterial, DNA, Ribosomal, Gammaproteobacteria, Hydrogen, Ion Exchange, Membranes, Molecular Sequence Data, Nitrites, Oxidation-Reduction, Perchloric Acid, Phylogeny, RNA, Ribosomal, 16S, Sequence Analysis, DNA, Water Pollutants, Chemical, Water Purification},
	issn = {1097-0290},
	doi = {10.1002/bit.22414},
	author = {Sahu, Ashish K and Conneely, Teresa and N{\"u}sslein, Klaus and Ergas, Sarina J}
}
