IMPACT OF CHLOROPHENOLS AND CHLOROANILINES ON THE KINETICS OF ACETOCLASTIC METHANOGENESIS

Bench-scale tests were conducted to assess the impact of monochlorophenols and monochloroanilines on the kinetics of acetoclastic methanogenesis. The procedure involved adding toxicant at two to three concentrations to cultures transferred from an acetate-enriched seed culture reactor. A control without toxicant was included as a basis for comparison. Unacclimated cultures were used to minimize the biodegradation of the toxic organic chemicals during the test. A finite-difference, nonlinear, least-squares algorithm was used to estimate kinetic parameters by obtaining a best fit of the experimental data to the classical Monod growth and substrate utilization model. Resulting kinetic coefficients revealed substantial changes in both the maximum rate of acetate conversion, k, and the half-velocity coefficient, K(s), when both chlorophenols and chloroanilines were used. Therefore, mixed inhibition was occurring.