Explaining the enhanced performance of pulsed bioreactors by mechanistic modeling

Abstract

in Wiley InterScience (www.interscience.wiley.com).In this work, steady-state mass balance based models were applied to two UASB reactors and three UAF for a better understanding of the role of pulsation on the efficacy improvement. Models were defined taking into account the hydraulic behavior of each digester and the limiting mechanism of the overall process kinetics (mass transfer or biochemical reaction rate). The application of the model allows to identify that mass transfer was the controlling step in all the reactors, except for the nonpulsed UASB, where methanogenic activity controlled the reactor performance in the last operation steady states. Mass transfer coefficients were higher for pulsed reactors and, in general, a good agreement between those estimated by an empirical correlation and from the model was obtained. Damko¨hler number values supported that the external mass transfer resistance was not negligible with respect to the process kinetic and in addition, in most cases, it controls the overall process in the reactors. The relative importance of external and internal mass transfer rate was calculated through the Biot number. The values of this dimensionless module indicated that external transport was the main contributor to overall mass transfer resistance.

Model-based experimental analysis of enzyme kinetics in aqueous–organic biphasic systems

“…For example, Franco et al (2008) have demonstrated that mechanistic kinetic modeling can explain the enhanced performance of pulsed bioreactors. However, the mechanistic modeling of (bio-)chemical reactions in homogeneous and heterogeneous systems is still one of the most relevant and yet not satisfactorily solved tasks in process engineering (Berger et al, 2001).…”

Biofilm Fixed Film Systems

“…In another study, a steady state mechanistic model was applied to explain the role of pulsation on the performance enhancement for UASB and UAF (Franco et al, 2008). The model revealed that mass transfer was higher in pulsed reactors and thus mass transfer was a controlling step in all reactors.…”