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

Bioresour Technol. 2024 Nov 25:131892. doi: 10.1016/j.biortech.2024.131892. Online ahead of print.

Abstract

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.

Keywords: Biomass recovery; Dewatering; Flocculation; Flotation; Large-scale harvesting; Microalgae harvest.