HARVESTING MARINE MICROALGAE (TETRASELMIS SP.) USING DIELECTROPHORETIC FORCE-ASSISTED ELECTROCOAGULATION

Abstract

The attention towards algal based products has been increasing drastically in recent years. The high energy requirement for harvesting microalgae stands as the main challenge of the production stream of the biomass. The presented study examined the performance of using interdigitated electrodes for harvesting marine microalgae (Tetraselmis sp.) in electrocoagulation. It was found that the new electrode array exerted a dielectrophoretic (DEP) force that improved the performance of the process compared to using a parallel of flat sheet electrodes. This phenomenon was confirmed through numerical simulation and analysis. Through experimental validation, harvesting efficiency of 82.4% was achieved with 10 mins electrolysis time when applying 50 mA/cm2 current density at an inter-electrode spacing of 1 cm. Moreover, the maximum harvesting efficiency achieved was 96,18% at an inter-electrode spacing of 0.5 cm of the new electrode array. The specific energy consumption of the new electrode shows 38% enhancement than using a pair of parallel flat sheet electrode. The aluminum analysis confirmed better coagulant attachment when using the interdigitated electrode array than using the conventional flat sheet electrode. The enhanced performance of the electrocoagulation process was confirmed in terms of dielectrophoretic induction, electrode passivation, and improved current efficiency in the proposed electrode array.