Vinyl chloride and cis-dichloroethene dechlorination kinetics and microorganism growth under substrate limiting conditions.

TitleVinyl chloride and cis-dichloroethene dechlorination kinetics and microorganism growth under substrate limiting conditions.
Publication TypeJournal Article
Year of Publication2004
AuthorsCupples, AM, Spormann AM, McCarty PL
JournalEnvironmental science & technology
Volume38
Issue4
Pagination1102-7
Date Published2004 Feb 15
ISSN0013-936X
KeywordsBacteria, Biodegradation, Environmental, Carcinogens, Dichloroethylenes, Kinetics, Models, Theoretical, Population Dynamics, Soil Microbiology, Soil Pollutants, Vinyl Chloride
AbstractThe reductive dechlorination of tetrachloroethene (PCE) and trichloroethene (TCE) at contaminated sites often results in the accumulation of cis-1,2-dichloroethene (DCE) and vinyl chloride (VC), rather than the nonhazardous end product ethene. This accumulation may be caused by the absence of appropriate microorganisms, insufficient supply of donor substrate, or reaction kinetic limitations. Here, we address the issue of reaction kinetic limitations by investigating the effect of limiting substrate concentrations (electron donor and acceptor) on DCE and VC dechlorination kinetics and microorganism growth by bacterium VS. For this, a model based on Monod kinetics, but also accounting for competition between electron acceptors and the effect of low electron donor and acceptor concentrations (dual-substrate kinetics), was examined. Competitive coefficients for VC (7.8 +/- 1.5 microM) and DCE (3.6 +/- 1.1 microM) were obtained and included in the model. The half velocity coefficient for hydrogen, the electron donor, was experimentally determined (7 +/- 2 nM) through investigating dechlorination over different substrate concentrations. This complete model was then used, along with experimental data, to determine substrate concentrations at which the dechlorinating microorganisms would be in net decay. Notably, the model indicates net decay will result if the total electron acceptor concentration (DCE plus VC) is below 0.7 microM, regardless of electron donor levels. The ability to achieve sustainable bioremediation to acceptable levels can be greatly influenced by this threshold level.
Alternate JournalEnviron. Sci. Technol.
0 November 24, 2010