Modeling of the fate and effect of chlorinated phenols in anaerobic treatment processes

Studies were conducted to assess the biotransformation kinetics and inhibitory effects of mono-, di-, and trichlorophenol on acetogenic and methanogenic reactions using a standardized anaerobic protocol (Young and Tabak, 1993). Intrinsic kinetic parameters were estimated for each reaction using the Monod model. Reductive dechlorination of the toxicants was investigated using acclimated mixed cultures under methanogenic conditions. The studies indicated that inhibition of acetogenesis and methanogenesis was best described using exponential rather than linear inhibition terms. A second significant observation was that acclimated test cultures had a finite biodegradation capacity for each chemical that was related to the mass of microorganism present. A unique feature of the test program was that inhibition and biodegradation were modeled using the specific biomass responsible for acetogenesis and methanogenesis rather than the total anaerobic biomass. (C) 1997 IAWQ. Published by Elsevier Science Ltd.