Modeling of immobilized cell columns for bioconversion and wastewater treatment.

Immobilized cells are widely used in bioconversions to produce biological products as well as in wastewater treatment such as solvent removal from wastewater streams. In this work, a rate model is proposed to simulate this kind of process in an axial-flow fixed-bed column packed with porous particles containing immobilized cells. The transient model considered various mass transfer mechanisms including axial dispersion, interfacial film mass transfer, and intraparticle diffusion. Cell death in the immobilized cell system was also considered. Effects of various parameters such as kinetic constants and mass transfer parameters were studied. Operational situations such as feed fluctuation flow rate increase and two columns in series were also investigated. The model can be used to study the behavior and characteristics of immobilized cell columns in order to perform scale-up predictions of effluent profiles and for the purpose of process optimization.