Pilot scale microalgae harvesting by a membrane: cross flow vs. submerged membrane

Harvesting microalgal biomass is a major challenge because of their small size, their density, and their low concentration in the culture medium. Thus, the energy inputs to the cultivation/harvesting processes are high, and often exceed the energy content of the microalgal biomass itself. In this study, the cross-flow membrane and submerged membrane systems were installed to raceway ponds, and the harvesting yields were compared. The highest algal concentration reached by submerged membrane system which was 10.44 g/L; and by cross-flow membrane system maximum biomass reached was 6.99 g/L, which corresponds to concentrate 6 and 4.2 fold, respectively.