title: Biodegradation of chlorinated aliphatic hydrocarbon mixtures in a single-pass packed-bed reactor.
abstract: Aliphatic chlorinated compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), are major contaminants of ground water. A single-pass packed-bed bioreactor was utilized to study the biodegradation of organic waste mixtures consisting of PCE, TCE, and other short-chain chlorinated organics. The bioreactor consisted of two 1960-mL glass columns joined in a series. One column was packed with sand containing a microbial consortia enriched from a contaminated site. The other column provided a reservoir for oxygen and a carbon source of methane/propane that was recirculated through the reactor. Sampling was accomplished by both direct headspace and liquid effluent concentration analyses. The reactor was operated in a single-pass mode. Greater than 99% degradation of trichloroethylene, approaching drinking water standards, was observed when the bioreactor residence time ranged from 1.9 to 3.2 d. Typically, when the reactor was pulse-fed with methane, propane, and air, 1 mol of TCE was degraded/110 mol of substrate utilized. Perturbation studies were performed to characterize reactor behavior. The system's degradation behavior was affected by providing different carbon sources, a pulse feeding regime, supplementing microbial biomass, and by altering flow rates.
authors.affiliation: Center for the Environmental Biotechnology, University of Tennessee-Knoxville 37996-2200.
authors.forename: L W
authors.initials: LW
authors.lastname: Lackey
authors.forename: T J
authors.initials: TJ
authors.lastname: Phelps
authors.forename: P R
authors.initials: PR
authors.lastname: Bienkowski
authors.forename: D C
authors.initials: DC
authors.lastname: White
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002849:Chromatography, Gas; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D008956:Models, Chemical; D013750:Tetrachloroethylene / Q000378:metabolism; D014241:Trichloroethylene / Q000378:metabolism
chemical_list: D006843:Hydrocarbons, Chlorinated; D014241:Trichloroethylene; D013750:Tetrachloroethylene