Determination of effectiveness factor for immobilized cells on solid supports

A combination of Monod kinetics and diffusion equation was used for evaluating the effectiveness factor for immobilized cells on solid supports. This has revealed that there is an optimal value of biofilm thickness which results in a maximum for the effectiveness factor. The optimal value of biofilm thickness becomes smaller with increasing values for the Thiele modulus. The effectiveness factor increases as the saturation constant increases for a given value of the Thiele modulus. Furthermore, optimal range of biofilm thickness becomes broader with increasing values for the saturation constant. At large Thiele moduli, an analytical solution based on approximate kinetics is sufficiently accurate to permit a useful estimation of the effectiveness factor.