PARAMETRIC SENSITIVITY OF COMPREHENSIVE MODEL OF AEROBIC FLUIDIZED-BED BIOFILM PROCESS

A theoretical model describing the various kinetic reactions occurring in a biological fluidized-bed reactor is presented. It covers both th e unsteady and steady conditions of the process, taking into account t he bulk liquid biomass activity and adopting Rittmann's (1982) shearin g 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 suspe nded microorganisms in the bulk Liquid medium; and (4) the microorgani sms attached to the solid media. The sensitivity of each of the four s tate variables to various biological parameters, and system design var iables were investigated at steady-state conditions. The sensitivity a nalysis showed that the main factors affecting the process state varia bles were fluidization velocity, size of the solid media, initial bed porosity, specific yield, and a maximum rate of substrate utilization.