ACCLIMATION OF A METHANOGENIC CONSORTIUM TO A MIXTURE OF HYDROXYLATEDAROMATIC-COMPOUNDS

Using an anaerobic model-soil column, a non acclimated methanogenic mi xed culture was exposed to increasing loading rates of a mixture of hy droxylated aromatic compounds in the presence of citrate as growth sub strate. The toxic mixture consisted of 2,4,6-trichlorophenol (TCP), l- naphthol and 2-nitrophenol (2NP). The results showed that the period o f methanogenic adaptation to this mixture of chemicals, as reflected b y durable methane production, was relatively long (more than 200 days) . TCP was transformed to 4-chlorophenol (4CP). The biotransformation o f 2NP resulted in the formation of 2-aminophenol (2AP). The maximum de gradation rates observed were 25 mg/l. d, 18 mg/l. d, 22 mg/l. d and 7 mg/l. d for 2NP, l-naphthol, TCP and 4CP respectively. l-Naphthol, TC P and 2NP degradations do not seem to be directly related to methane p roduction. (C) 1998 Elsevier Science Ltd.