The effects of varying the levels of cell disruption achieved by high-pressure homogenization upon subsequent centrifugal separation of cell debris have been defined by measuring sedimentation velocity distributions of the cell debris. Using this data together with particle size distributions, a computer-based model of a disk stack centrifuge has been used to predict the efficiency of centrifugal separation. These predictions have been compared with both laboratory scale and pilot plant scale experimental results. A similar sedimentation velocity technique has been used to characterize the properties of the flocs formed by addition of poly(ethylene imine) to a borax-clarified homogenate supernatant. The variations of floc settling properties with respect to polymer concentration are defined.