RESPIROMETRIC TECHNIQUE FOR DETERMINATION OF EXTANT KINETIC-PARAMETERS DESCRIBING BIODEGRADATION

A batch respirometric test was developed to measure the response of ac tivated sludge communities degrading low concentrations of organic che micals. The low substrate concentrations used in the assay ensure that minimal changes occur in the physiological state of the degrading com munity. The estimated kinetic parameters are, therefore, extant, that is, representative of the existing condition of the biomass in the con tinuous bioreactor. Monte Carlo and sensitivity analyses were performe d to verify the robustness of the technique for determining unique and accurate estimates of the parameters describing Monod and Andrews kin etics. Application of the technique to a laboratory-scale activated sl udge system showed that kinetic parameter estimates were reproducible and independent of the substrate concentration within the range tested (0.2-4.0 mg/L as chemical oxygen demand [COD]). Low K-S values (< 0.1 mg/L as COD) were measured by the assay for the biodegradation of phe nol and 4-chlorophenol, both of which exhibited an inhibitory response (Andrews kinetics). The biodegradation of ethylene glycol, acrylamide , and acetate exhibited Monod kinetics.