Advanced, Low-Cost, System for Algae Dewatering

Development of liquid transportation fuels from biomass is an essential part of diversifying the U.S. energy portfolio. Algae represents a promising next generation bioenergy source for producing energy from renewable sources because of the fast growth and high oil content of certain algae strains. However, because of very dilute concentrations of algae in the feed and consequently very large volumes of water that must be processed, harvesting algae contributes significantly to the cost of algal biofuel production. Cost effective algae dewatering technology is needed to reduce cost of algal biofuels. Membrane filtration technology has several advantages over other solid-liquid separation technologies such as simple modular operation, compact units and lower energy requirement compared to centrifuge. However membrane technology is not widely used because of membrane fouling and module blockage issues as the algae solids content is increased. The proposed effort will address these issues by using open channel module design. The Phase I effort will develop a two-stage membrane filtration-based algae dewatering system and demonstrate >20% w/w algae paste production with >25% reduction in costs and >20% reduction in energy demand using algae produced in differing production platforms: open ponds, closed photobioreactors, and hybrid open/closed algae growth system. A low-cost, high volume spiral wound module will be used for stage 1 to remove bulk of water and a high-performance SmartFlow membrane module will be used to produce thick algae paste. The proposed Phase I effort will develop a cost-effective algae dewatering system which will help reduce the cost of biofuel production from algae. Several other applications are also sought for algae such as in nutraceutical and food industries and for bioplastics. The proposed development will help to make algal products affordable.