title: Continuous flocculation-sedimentation for harvesting Nannochloropsis salina biomass.
abstract: A continuous flow process is developed for recovery of the biomass of the marine microalga Nannochloropsis salina. Flocculation-sedimentation is used to recover the biomass from an algal suspension with an initial dry biomass concentration of 0.5 g L(-1), as would be typical of a raceway-based biomass production system. More than 85% of the biomass initially in suspension could be settled by gravity in a flocculation-sedimentation device with a total residence time of ∼148 min. Aluminum sulfate was used as an inexpensive, readily available and safe flocculant. The optimal flocculant dosage (as Al2(SO4)3) was 229 mg L(-1). Relative to a highly effective 62-min batch flocculation-sedimentation process for the same alga and flocculant, the continuous flow operation took longer and required nearly double the flocculant dose. The design of the flocculation-sedimentation system is explained.
authors.affiliation: School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
authors.forename: Tawan
authors.initials: T
authors.lastname: Chatsungnoen
authors.affiliation: School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand. Electronic address: Y.Chisti@massey.ac.nz.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Chisti
mesh_terms: D056804:Biofuels; D018533:Biomass; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D005427:Flocculation; D058009:Stramenopiles / Q000166:cytology / Q000502:physiology
chemical_list: D056804:Biofuels
keywords: Biofuels; Flocculation–sedimentation; Nannochloropsis salina; microalgae