title: Degradation of 2,4,5-trichlorophenol and 2,3,5,6-tetrachlorophenol by combining pulse electric discharge with bioremediation.
abstract: Degradation of 2,4,5-trichlorophenol (2,4,5-TCP) and 2,3,5,6-tetrachlorophenol (TeCP) was studied using a two-stage approach that utilized efficient pulse electric discharge (PED) followed by biological degradation with a consortium from acclimated return activated sludge. The chlorinated phenols were treated in the PED reactor as an aerosol at a voltage of 55-60 kV, a frequency of 385 Hz, a current of 50-60, and with a 200-ns pulse. As determined by gas chromatography and mass spectrometry (GC/MS), the first stage converted 500 ppm 2,4,5-TCP to 163 ppm 2,4,5-TCP and dimethyldecene, dichloronaphthalenol, octyl acetate, and silyl esters. The total carbon content of 2,4,5-TCP after PED treatment was determined to be 228 +/- 35 ppm. The remaining 2,4,5-TCP and the products formed were then mineralized by the acclimated activated sludge in shake flasks; the initial rate of degradation of 2,4,5-TCP was calculated to be 5 nmol min-1 mg protein-1 at 163 ppm initial concentration (three orders of magnitude higher than the only rate found in the literature). By combining the two techniques, a synergistic effect (2.3-fold increase in the concentration of 2,4,5-TCP degraded and 3.3-fold increase in total carbon degraded) was observed, in that bacteria without any treatment degraded a maximum of 70 ppm, 2,4,5-TCP but after PED treatment 163 ppm 2,4,5-TCP was degraded. TeCP was also mineralized by the acclimated activated sludge after treatment with PED. This two-stage approach was also evaluated using a continuous 1-l fluidized-bed reactor.
authors.affiliation: Department of Chemical Engineering, University of Connecticut, Storrs 06269-3222, USA.
authors.forename: S
authors.initials: S
authors.lastname: Chauhan
authors.forename: E
authors.initials: E
authors.lastname: Yankelevich
authors.forename: V M
authors.initials: VM
authors.lastname: Bystritskii
authors.forename: T K
authors.initials: TK
authors.lastname: Wood
mesh_terms: D002733:Chlorophenols / Q000737:chemistry / Q000378:metabolism*; D004560:Electricity; D004566:Electrodes; D004785:Environmental Pollutants / Q000378:metabolism*; D007477:Ions; D010084:Oxidation-Reduction; D012722:Sewage
chemical_list: D002733:Chlorophenols; D004785:Environmental Pollutants; D007477:Ions; D012722:Sewage; C009534:2,4,5-trichlorophenol; C039673:2,3,5,6-tetrachlorophenate