Maximizing the impact of air bubbles for membrane fouling control in microalgae harvesting

Abstract

Harvesting microalgae using membrane is challenging due to the nature of microalgae having very high membrane fouling potential. Numerous techniques have been proposed for membrane fouling control, including optimizing operational cycles, imposing shear-rates via air bubbles and dosing chemicals for feed conditioning and membrane cleaning. As an established method, the eficacy of air bubbles for membrane fouling control can be improved by maximizing the impact of shear-rates in scouring foulant from the membrane surface. In this study, we investigate the effect of tilting angles, switching periods as well as aeration rates in a lab-scale submerged iltration system by iltering microalgae solution. Results showed that higher tilting angles improve the cleaning eficiency by offering higher lux of up to 2.7 times at an angle of 20◦ as opposed to the vertical one. It was also found that operating a one-sided panel (without switching) was about 20% better than a two-sided panel, in which the latter involved switching mode to offer aeration of both panel sides. This technique is effective in controlling fouling and can lead to energy saving for full-scale modules.