Separation efficiency of a vacuum gas lift for microalgae harvesting.

Low-energy and low-cost separation of microalgae from water is important to the economics of microalgae harvesting and processing. Flotation under vacuum using a vacuum gas lift for microalgae harvesting was investigated for different airflow rates, bubble sizes, salinities and harvest volumes. Harvesting efficiency (HE) and concentration factor (CF) of the vacuum gas lift increased by around 50% when the airflow rate was reduced from 20 to 10 L min(-1).