A strategy for urban outdoor production of high-concentration algal biomass for green biorefining

► C. sorokiniana's adaptability in 12-h interchanging trophic conditions was studied. ► Cell productivity and C-N-P removals under various conditions were determined. ► Microalgae flocculation using chitosan is dependent on chitosan: cell (w/w) ratio. ► Achieved reproducible >99% flocculation and >20% solids algae broth.