Economic and demonstrative pilot-scale harvesting of microalgae biomass via novel combined process of dissolved air flotation and screw-press filtration

• Published in: Bioresource technology 2024-11, Vol.418, p.131892, Article 131892
• Main Authors: Yoon, Hyo Jik, Lee, Jeong Seop, Min, Ki Ha, Kim, Dong Hyun, Sim, Sang Jun, Pack, Seung Pil
• Format: Article
• Language: English
• Subjects: Biomass recovery; Dewatering; Flocculation; Flotation; Large-scale harvesting; Microalgae harvest
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131892

[Display omitted] •The first report on pilot-scale microalgae harvest using floatation and filtration process.•Innovative combined-method reduces energy use in pilot-scale microalgae recovery.•Achieved 93 % harvesting efficiency with 1.7 kWh/m3 average energy consumption.•Energy consumption in pilot-scale process was lower by 60.5% than centrifugation. Microalgae, a promising sustainable biomass resource, lacks sufficient research for pilot-scale processes despite available technologies. Harvesting methods also pose challenges for large-scale applications. To address this, the economically viable large-scale microalgae harvesting system is here presented. The design integrates dissolved air flotation (5 m3/h) and screw-press filtration (10 kg/h), minimizing energy consumption suitable for industrial processes. This system efficiently harvests chlorella sp. (up to 4.1 m3) with a biomass harvest efficiency of 93 % and a dewatering rate of 11.9 %. Compared to centrifugation, the multi-stage system improves energy efficiency by 60.5 % with 1.7 kWh/m3 of energy consumption. This innovative approach demonstrates the potential for large-scale microalgae biomass harvesting.