Inhibiting action of chlorophenols on biodegradation of phenol and its correlation with structural properties of inhibitors.

An activated sludge conditioned to a low concentration of phenol was used for the biodegradation of phenol in the presence of Chlorophenols, measuring the inhibiting action of all the latter compounds and expressing it as p/(50.) As a structural property to be correlated with the measured values, the lipophilicity (log P) of the Chlorophenols was reevaluated with a new apparatus. Values of p/(50)p are better correlated with the number of chloro substituents in the inhibitor, provided a specific effect of substituents ortho to the phenolic function is considered. New results are compared with previous measurements effected on a different activated sludge.