Interaction of Mass Transfer and Inhibition in Biofilms

Abstract

Two kinetic inhibition models were considered in concert with mass transport equations in biofilm to demonstrate how these phenomena interact, and explain, in principle, why fixed‐film processes may be more stable than their dispersed growth counterparts. For substrate inhibition, the reaction rate in the biofilm, at reduced concentration, can be up to 250% greater than in the bulk solution under strong inhibition. Regions of multiple solutions of the model equations were observed. In cases where product inhibition occurs, the biofilm reaction rate is always less than in the bulk solution, but the mass transfer effect is small under strong inhibition. These calculations offer a strong foundation for the enhanced stability often seen with fixed‐film wastewater treatment processes.