Flocculant Screening Method at Lab Scale for Application in Disc Stack Centrifuges with Hermetic Design.

Chemicals produced using biotechnological methods like fermentation processes are obtained as complex diluted aqueous mixture, which still contains the production organism. Centrifugation is a commonly used technology for biomass separation. By flocculation, the settling velocity of microorganisms can be increased. Here, a laboratory flocculant screening method tailored for the separation of flocculated biomass in a fully hermetic disc stack centrifuge is described. The specific requirements of this process, namely, floc formation, floc stability, sliding behavior in the disc stack, and flowability of the sludge, were transferred to lab scale and validated in pilot tests. The qualitative results of the laboratory screening were in agreement with the processes at industrial scale.