(575d) Enhanced Separation of Algal Biomass By Vibratory Shear Microfiltration for the Sustainable Production of Biofuels

The dewatering step in the production of algal biofuels is energy intensive resulting in a significant carbon footprint.  Membrane separations are one of the processes being investigated to increase efficiency of the operation, but have limitations due to concentration polarization and fouling.  This is a concern that limits the scale-up potential of this process for commercial biorefineries.  To overcome issues with flux degradation, we have investigated shear-enhanced cross-flow membrane filtration processes.  High membrane shear rates were achieved by high-frequency torsional oscillations of the membrane unit.  Operated at the resonant frequency, these systems can provide enhanced separation performance at minimal power inputs.  Several microfiltration membranes have been evaluated for the separation of dissolved Chlorella Vulgaris, a potential feedstock for biodiesel production.  This process provides a greener alternative to conventional systems, as high values of flux and separation efficiency can be maintained and the biomass can be effectively concentrated.  Studies to evaluate the effect of algae feed concentration, membrane pore size, trans-membrane pressure, and vibrational amplitude on permeate flux were performed.  The integration of vibratory field membrane separation into an overall design for the dewatering of algal biomass can result in a more sustainable, greener system.