Exploiting flocculation and membrane filtration synergies for highly energy-efficient, high-yield microalgae harvesting

High energy consumption during harvesting is one of the main bottlenecks for sustainable microalgae production. Membranes can efficiently separate from liquids with low consumption, but membrane fouling remains an important issue. Flocculation prior to filtration increase fluxes and decrease fouling, thus offering a low-cost efficient solution harvest microalgae. Biobased cationic cellulose nanocrystals were successfully used as flocculants effective over wide pH-range both freshwater marine Such flocculation was first time combined vibration-assisted using charged, surface patterned membrane, enabling operation at very high flux (95 L/m2 h) vibration frequency only 1 Hz, even under sub-optimal conditions. Intermittent decreased further while keeping excellent performance finally achieve record-low 6.7 Wh/m3, which >25-times lower than that normal filtration. Interaction forces revealed increasing particle size through significantly prevent attachment on vibrating surface. This work opens new direction ultra-low recovery, reduced use chemicals, investment cost.