title: Membrane-based energy efficient dewatering of microalgae in biofuels production and recovery of value added co-products.
abstract: The objective of this paper is to describe the use of membranes for energy efficient biomass harvesting and dewatering. The dewatering of Nannochloropsis sp. was evaluated with polymeric hollow fiber and tubular inorganic membranes to demonstrate the capabilities of a membrane-based system to achieve microalgal biomass of >150 g/L (dry wt.) and ∼99% volume reduction through dewatering. The particle free filtrate containing the growth media is suitable for recycle and reuse. For cost-effective processing, hollow fiber membranes can be utilized to recover 90-95% media for recycle. Tubular membranes can provide additional media and water recovery to achieve target final concentrations. Based on the operating conditions used in this study and taking into scale-up considerations, an integrated hollow fiber-tubular membrane system can process microalgal biomass with at least 80% lower energy requirement compared to traditional processes. Backpulsing was found to be an effective flux maintenance strategy to minimize flux decline at high biomass concentration. An effective chemical cleaning protocol was developed for regeneration of fouled membranes.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States. bhaverr@ornl.gov
authors.forename: Ramesh
authors.initials: R
authors.lastname: Bhave
authors.forename: Tanya
authors.initials: T
authors.lastname: Kuritz
authors.forename: Lawrence
authors.initials: L
authors.lastname: Powell
authors.forename: Dale
authors.initials: D
authors.lastname: Adcock
mesh_terms: D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D003246:Conservation of Energy Resources / Q000379:methods*; D005427:Flocculation; D008567:Membranes, Artificial; D058086:Microalgae / Q000254:growth & development / Q000378:metabolism*; D010539:Permeability; D016062:Porosity; D011312:Pressure; D012212:Rheology; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D056804:Biofuels; D008567:Membranes, Artificial; D014867:Water