BIODEGRADATION OF PHENOLIC-COMPOUNDS BY AN ACCLIMATED ACTIVATED-SLUDGE AND ISOLATED-BACTERIA

The degradation of a mixture of phenol, 4-chlorophenol (4CP), 2, 1-dic hlorophenol (24DCP) and 2,4,6-trichlorophenol (246TCP) by acclimated a ctivated sludge and by isolated bacteria was studied. Activated sludge was acclimated for 70 days to 40 mg phenols/l then the microorganisms responsible for the CP degradation were isolated and identified. Four types of Gram-negative bacteria (Aeromonas sp., Pseudomonas sp. Flavo monas oryzihabitans, and Chryseomonas lateola) were identified. Also, two acid-fast bacilli with distinct glycolipid patterns were isolated. From their chemical composition and their growth characteristics, bot h isolates appeared to be mycobacteria closely related to Mycobacteriu m peregrinum. The degradation kinetics of each phenol by Aeromonas sp. , Pseudomonas sp. Flavomonas oryzihabitans. Chryseomonas luteola and a ctivated sludge were determined. The acclimated activated sludge degra dation rates were from one to two orders of magnitude higher than thos e of pure strains when uptake rates were calculated in terms of the vi able biomass (CFU). The specific substrate uptake rate for acclimated activated sludge varied between 8.2 and 15.8 x 10(-7) mg/CFU.d (407-78 4 mg/gVSS.d). Aeromonas sp. had the highest specific substrate uptake rate of the pure strains, based on a VSS basis (33-57 mg/gVSS.d) but, in terms of viable biomass (5.0-15.6 x 10(-8) mg/CFU.d). the Pseudomon as sp. rate was the highest. Specific substrate uptake rates were 1.8 mg chlorinated phenols/g VSS.d for unacclimated activated sludge. (C) 1998 IAWQ. Published by Elsevier Science Ltd.