Biomass separation sedimentation

Biomass separation of insoluble from soluble material, with either phase being retained depending on the location of the product as intracellular or extracellular material. Examples of unit operations commonly used include centrifugation, filtration, and sedimentation. 

Common anaerobic bioreactor configurations are designed to obtain good mixing and biomass separation. This can be achieved by filtration, sedimentation and digestion before returning the clarified or treated liquid to the bioreactor use of anaerobic filters or upflow clarification or the use sequential reactors systems (Stephenson et al., 2002). Some of the most utilized anaerobic reactor configurations are briefly described below. 

Membrane bioreactors combine the activated sludge process for wastewater treatment with biomass separation from the mixed liquor by ultra- or microfiltration membranes. Advantages are the superior effluent quality characterized by complete solids removal and disinfection, the small footprint of the plant resulting from more compact aeration tanks, the absence of a secondary sedimentation tank, and the modular construction. 

Yeast separation and concentration. Extraction of ethanol from biomass requires several separation steps, traditionally by centrifuging, sedimentation and cake filtration. First, after the fermentation, the yeast is removed from the fermentation broth and may be recycled. Additionally, after ethanol is stripped from the fermentation broth by steam followed by the removal of solid fractions, the remaining material called the thin stillage can be clarified for reuse upstream as the process water. 

Downstream processing constitutes a key part of the entire PHA production process. After biosynthesis of the polyester and separation of the bacterial biomass (normally by well-established techniques like centrifugation, sedimentation, flocculation or filtration), the process required for PHA recovery from the microbial cell mass must be considered as an important cost factor, especially considering large scale production. Choosing the adequate method for separating PHAs from residual biomass is dependent on several factors the production strain, the required product purity that is determined by the final application of the biopolymer, the... 

The separation of biomass from growth media is a difficult operation, as cells have almost the same density as their surrounding medium, are small, are able to form stable colloids and are cohesive. Sedimentation of cell debris presents an even more difficult problem for biotechnologists and the choice of separation technique is limited. Solid bowl and tubular bowl centrifuges are relatively inexpensive and have in the past been chosen for... 

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