The distributive properties of a fluidized bed with biomass

Abstract

This paper deals with the problem of an appropriate support particle size and its distribution in a fluidized bed bioreactor used for the denitrification of potable water. The derivation of the settling velocity ratio of particles with and without biomass has been presented and also an estimate for the change in drag coefficient due to the quality of the biomass has been attempted. The relations of the velocity ratio to the particle diameter ratio are shown graphically, with particular regard to the probable change in the drag coefficient. The settling velocities of support particles of two different diameters have been calculated both with and without the biofilm and the example displays the necessity of a monodisperse bed construction in order to secure the correct continuous function of the bioreactor. In cases where the diameters differ substantially, the larger particles will always stay below the smaller ones, and will not be carried up nor separated from the overgrown biofilm. © 1994.