title: A strategy for urban outdoor production of high-concentration algal biomass for green biorefining.
abstract: The present study was to investigate the feasibility of carrying out effective microalgae cultivation and high-rate tertiary wastewater treatment simultaneously in a vertical sequencing batch photobioreactor with small areal footprint, suitable for sustainable urban microalgae production. For 15 consecutive days, Chlorella sorokiniana was cultivated in synthetic wastewater under various trophic conditions. A cycle of 12-h heterotrophic: 12-h mixotrophic condition produced 0.98 g l(-1) d(-1) of algal biomass in tandem with a 94.7% removal of 254.4 mg l(-1) C-acetate, a 100% removal of 84.7 mg l(-1) N-NH4 and a removal of 15.0 mg l(-1) P-PO4. The cells were harvested via cost-effective chitosan flocculation with multiple dosing (3 times) applying established chitosan:cell ratio (1:300 w/w) and pH control (6.3-6.8). Reproducible flocculation efficiencies of greater than 99% and high-concentration algal broths (>20% solids) were achieved.
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore. limc0146@ntu.edu.sg
authors.forename: Chun Yong
authors.initials: CY
authors.lastname: Lim
authors.forename: Chia-Lung
authors.initials: CL
authors.lastname: Chen
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000085:Acetates / Q000302:isolation & purification; D052818:Autotrophic Processes; D001673:Biodegradation, Environmental; D018533:Biomass; D001709:Biotechnology / Q000191:economics / Q000379:methods*; D048271:Chitosan / Q000737:chemistry; D002947:Cities; D003362:Cost-Benefit Analysis; D005427:Flocculation; D055772:Green Chemistry Technology / Q000191:economics / Q000379:methods*; D052836:Heterotrophic Processes; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000254:growth & development*; D009584:Nitrogen / Q000302:isolation & purification; D010710:Phosphates / Q000302:isolation & purification; D010758:Phosphorus / Q000302:isolation & purification; D000644:Quaternary Ammonium Compounds / Q000302:isolation & purification
chemical_list: D000085:Acetates; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D010758:Phosphorus; D048271:Chitosan; D009584:Nitrogen