Dewatering of Arthrospira platensis microalgae suspension by electrofiltration

Abstract

Harvesting microalgae has presented many challenges in the past, especially when taking into account the final dryness of the product and the energy requirements for the drying process. This study investigates the use of dead-end electrofiltration to dewater an Arthrospira platensis suspension under different pressures (1 to 4 bar) and electric current densities (30 to 80 A/m2). Filtration without an electric field helped reach a final cake dryness in the range of 13.3-15%. Electrofiltration was found to be a more effective dewatering method, reaching a final cake dryness of up to 20.8% with an energy consumption of 0.105 kWh/kg water removed, which is significantly lower than the energy consumption reported in literature. Increasing the electric current density helped increase the cake dryness, whereas increasing the operating pressure was not effective enough due to the high cake compressibility. Electrofiltration also modifies the filtrate and cake properties due to the electrolysis reactions.