BIOLOGICAL FLUIDIZED-BEDS CONTAINING WIDELY DIFFERENT BIOPARTICLES

Bioparticles of widely varying size and density were partially intermi xed and segregated according to size, along the length of a solid-liqu id biological fluidized bed. The biomass concentration was not very se nsitive to the growth of bioparticles up to about 100 mg of attached b iomass/g sand; then, it decreased rather rapidly as more biomass accum ulated on the bioparticles. Although bed expansion characteristics wit h respect to upflow velocity could be described by the classic Richard son and Zaki equation, the expansion index could not be correlated wit h the terminal Reynolds number of a characteristic bioparticle with th e Sauter-mean diameter. The total bioparticle volume in the reactor es timated from the Sauter-mean diameter was about 25% more than that cal culated from the actual bioparticle size distribution.