Biological Fluidized Beds Containing Widely Different Bioparticles

Abstract

Bioparticles of widely varying size and density were partially intermixed and segregated according to size, along the length of a solid‐liquid biological fluidized bed. The biomass concentration was not very sensitive to the growth of bioparticles up to about 100 mg of attached biomass/g sand; then, it decreased rather rapidly as more biomass accumulated on the bioparticles. Although bed expansion characteristics with respect to upflow velocity could be described by the classic Richardson and Zaki equation, the expansion index could not be correlated with the terminal Reynolds number of a characteristic bioparticle with the Sauter‐mean diameter. The total bioparticle volume in the reactor estimated from the Sauter‐mean diameter was about 25% more than that calculated from the actual bioparticle size distribution.