Continuous foam flotation harvesting with enhanced drainage: Overcoming the recovery-enrichment paradox

Microalgae are promising sources of sustainable biofuels, however high harvesting and enriching costs hamper economic competitiveness. Foam flotation––a low-cost, low-energy adsorptive bubble separation technique––may bridge this gap, yet its efficiency adoption is compromised by a perceived trade-off (based on batch operation) between two key performance indicators: recovery percentage (R%) concentration factor (biomass enrichment ratio; CF). Previously, we challenged ‘recovery-enrichment paradox’ under continuous operation (R% 95, CF 173), but fell short expectation. Here, present redesign based the concepts process intensification, incorporating drainage riser, delivering concomitantly R% (91) (722), retaining low power consumption (0.052 kWh m−3 algae culture) with total suspended solids yield (14.6%). This compares very favorably other dewatering/harvesting techniques, overcoming paradox’. Our significant intensification foam flotation will accelerate advent economically microalgae derived biofuels.