Parametric Sensitivity of Comprehensive Model of Aerobic Fluidized-Bed Biofilm Process

Abstract

A theoretical model describing the various kinetic reactions occurring in a biological fluidized-bed reactor is presented. It covers both the unsteady and steady conditions of the process, taking into account the bulk liquid biomass activity and adopting Rittmann's (1982) shearing model. It is the result of four mass balance equations dealing with the state of the process. The state was defined by: (1) the substrate in bulk liquid medium; (2) the substrate in the biofilm; (3) the suspended microorganisms in the bulk liquid medium; and (4) the microorganisms attached to the solid media. The sensitivity of each of the four state variables to various biological parameters, and system design variables were investigated at steady-state conditions. The sensitivity analysis showed that the main factors affecting the process state variables were fluidization velocity, size of the solid media, initial bed porosity, specific yield, and a maximum rate of substrate utilization.