Biofiltration represents a novel strategy for controlling VOC emissions from a variety of industrial processes. A modeling approach for a trickle bed biofilter was developed in this work that incorporates several accepted idealizations about biofilm systems. The biofilter model proposed quantifies the treatment of a single component VOC waste stream in a system operating at steady state. Affects of biological growth on the hydrodynamics of the flow are accounted for, and the full Monod kinetic rate expression is used in describing VOC consumption in the biofilms. A relationship between the flux into a biofilm and the corresponding thickness is also incorporated into the model. This leads to a prediction of a biofilm profile through the bed depth with thicker films at the inlet of the filter where concentrations are higher.