Respirometric technique for determination of extant kinetic parameters describing biodegradation

Abstract

A batch respirometric test was developed to measure the response of activated sludge communities degrading low concentrations of organic chemicals. The low substrate concentrations used in the assay ensure that minimal changes occur in the physiological state of the degrading community. The estimated kinetic parameters are, therefore, extant, that is, representative of the existing condition of the biomass in the continuous bioreactor. Monte Carlo and sensitivity analyses were performed to verify the robustness of the technique for determining unique and accurate estimates of the parameters describing Monod and Andrews kinetics. Application of the technique to a laboratory‐scale activated sludge 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 Ks values (<0.1 mg/L as COD) were measured by the assay for the biodegradation of phenol and 4‐chlorophenol, both of which exhibited an inhibitory response (Andrews kinetics). The biodegradation of ethylene glycol, acrylamide, and acetate exhibited Monod kinetics.

In situ rapid measures of total respiration rate capture the super labile DOC bacterial substrates of freshwater

“…This is in stark contrast to the wastewater industry; over the same period, this industry has relied totally on estimates of heterotrophic bacterial respiration to predict the removal rate of DOC from domestic wastewater streams. For over 25 years, they have been using DO decay curves (oxygen uptake rates; OUR) in bench scale reactors (a small chamber style incubation) to successfully mathematically model heterotrophic bacterial community respiration rates for the design and control of biological wastewater treatment processes (Ekama et al 1986: Ellis et al 1996.…”

Investigating the kinetics of autotrophic denitrification with thiosulfate: Modeling the denitritation mechanisms and the effect of the acclimation of SO-NR cultures to nitrite

“…In particular, respirometry has been demonstrated as a powerful technique to gain insight on kinetics and stoichiometrics of biological processes [3][4][5] since biomass growth and substrate removal are directly associated with the electron acceptor consumption. Moreover, this technique allows obtaining biokinetic characteristics by modeling the respirometric profiles [6] as well as evaluating the inhibitory and/or toxic effects that a particular microbial population may suffer [7][8].…”

Biomass and microbial activity in a biofilter during backwashing

“…Aerobic microbes and the oxygen demand of icroorganisms which can cause removal of contamination complete in biofilter degradation (Ellis et al, 2000) complete in biofilter degradation. The units of biomass and microbial activity are nmol P/(cm 3 me- ceased when microbial activity increased.…”