Performance evaluation of biofilm reactors using graphical techniques

The dimensionless steady-state flux, J^*, of substrate into a biofilm can be expressed as a function of the concentration of substrate in the bulk, S_b^*, the thickness of the stagnant liquid layer surrounding the biofilm, L^*, and the minimum concentration of substrate capable of sustaining growth, S_min^*. Using a simplified algebraic expression that relates J^* to S_b^*, L^* and S_min^*, a series of nomograms were developed that give the performance of completely mixed (fluidized-bed) and plug-flow (packed-bed) biofilm reactors as a function of process parameters such as hydraulic retention time, kinetic constants and hydrodynamic conditions. The nomograms are simple to use and provide a tool for analyzing the performance of such reactors based in fundamental principles.