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

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.