title: Separation efficiency of a vacuum gas lift for microalgae harvesting.
abstract: 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). Reduced bubble size multiplied HE and CF 10 times when specific microbubble diffusers were used or when the salinity of the water was increased from 0‰ to 40‰. The reduction in harvest volume from 100 to 1L increased the CF from 10 to 130. An optimized vacuum gas lift could allow partial microalgae harvesting using less than 0.2 kWh kg(-1) DW, thus reducing energy costs 10-100 times compared to complete harvesting processes, albeit at the expense of a less concentrated biomass harvest.
authors.affiliation: ARDA, Station Marine du Port, Port Ouest, Hangar 10, 97420 Le Port, Reunion Island, France. bertrandbarrut@yahoo.fr
authors.forename: Bertrand
authors.initials: B
authors.lastname: Barrut
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Blancheton
authors.forename: Arnaud
authors.initials: A
authors.lastname: Muller-Feuga
authors.forename: François
authors.initials: F
authors.lastname: René
authors.forename: César
authors.initials: C
authors.lastname: Narváez
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Champagne
authors.forename: Alain
authors.initials: A
authors.lastname: Grasmick
mesh_terms: D061249:Batch Cell Culture Techniques / Q000295:instrumentation*; D019149:Bioreactors / Q000382:microbiology*; D002469:Cell Separation / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005740:Gases / Q000737:chemistry*; D058086:Microalgae / Q000302:isolation & purification*; D012212:Rheology / Q000295:instrumentation*; D013396:Suction / Q000295:instrumentation*
chemical_list: D005740:Gases