Abstract

Progress made in Commercializing the use of Membranes in Algal BioMass Processing

Pall Corporation is commercializing Algal Separation & Concentration Filter (ASCF) systems using membranes operating in crossflow mode to harvest and concentrate micro algae from growth mediums. Integrating the ASCF into the process requires the consideration of downstream algae biomass processing requirements. The optimal system design will depend on the biomass consistency and degree of dewatering required.

The effectiveness of the separation method used to dewater the biomass depends on properties specific to the algae suspension. Filtration works by separating materials of different sizes. In Crossflow filtration, the flow is parallel to the filter medium allowing 100 % separation and concentration of the algae while the growth medium passes through the filter medium. This provides the opportunity for optimal water/growth medium and nutrient management. With 100% of the algal biomass harvested with the membrane system, the effluent is free of solids that may otherwise require treatment for discharge. More important, the growth medium, free of biomass may be recycled back within the process. This enables water and nutrient management while achieving maximum biomass harvesting yields.

The effectiveness of cross-flow filtration to separate algae depends on the size of the algae in the nutrient broth, the membrane pore size and the system design. Costs for the equipment will depend on feed stream sizes and the final biomass concentration desired. Crossflow filtration is a low energy means for concentrating algae biomass. Determining the energy consumption at scale is one of the variables that Pall will be presenting from the data collected during its six plus years working on optimizing the use of membranes for commercial scale algae production.

Multiple membrane based integration strategies for algae processes will be presented along with the current status of commercialization and topics under further refinement.