Response of phenol-acclimated activated sludge process to quantitative shock loading

Research in the biological treatment of toxic wastes is of great importance to water pollution control efforts, as it is becoming clear that biological treatment will be expected to provide the bulk of wastewater purification. Furthermore, biological treatment will be called on to remove an increasing variety of toxic components. Phenol and phenolic compounds can be expected to constitute an increasingly larger part of these toxic organic loadings as the use of coal for energy and chemical feed stock increases. Previous reports have described research which led to the conclusion that a model embodying the Haldane relationship between specific growth rate, p., and substrate concentration, S, should be used to describe the kinetics of phenol removal in biological treatment systems.1'2 Average values and ranges for the biokinetic constants \imax, Ks, and K? were determined using data from more than 100 growth studies.2 These values and the kinetic model predicted performance for both a once through chemostat2 and an activated sludge system operated with constant recycle sludge concentration (XR)1 better than did a model which did not include an inhibition term. A problem that affects both design and operation of activated sludge systems treating toxic substrates is readily apparent when the effect of a toxic substrate on growth rate is considered. The relationships between n and S for nontoxic substrates (the