Harvesting of microalgae using flocculation combined with dissolved air flotation

This study explored efficient methods of harvesting the Tetraselmis sp. KCTC12236BP using flocculation and dissolved air flotation. Concentration ranges of flocculation agents were optimized using jar tests (batch flocculation experiments) using inorganic (aluminum sulfate, ferric sulfate) and organic (chitosan) flocculants in a pH range of 4 ～ 10. The optimal dosage and pH level were 1.2 g/L and pH 5 ～ 6 for aluminum sulfate, 0.7 g/L and pH 4 ～ 8 for ferric sulfate, and 5.0 mg/mL and pH 7 ～ 8 for chitosan. The highest harvesting efficiency achieved with each of the four compounds was 85.6, 92.6, 93, and 91.3%, respectively.