Abstract
Dynamic filtration is promising for microalgae harvesting and mitigation of fouling and has been used for various purposes, such as yeast separation, soy milk protein concentration, whey protein microfiltration, etc. This contribution reviews different designs of dynamic filtration systems. It aims to investigate and highlight the potential of dynamic filtration for microalgae harvesting. The performances of individual systems are compared. Dynamic filtration systems can yield permeate flux almost twice higher than systems using cross-flow filtration. Considering the filtration flux and power consumption, the optimal recommended disks for dynamic filtration are those with a gap between the disk and the membrane of 3 mm and disks with two vanes with a cross-sectional area that decreased in the outward direction from the disk center. Disks with two vanes or perforated disks are recommended to achieve a uniform distribution of shear stress along the membrane. Fluid velocity is 2-fold and shear stress 7-fold higher than those obtained for an unperforated disk. Due to the energy demand during dynamic filtration, it is not recommended to use the frequency of disk revolution higher than 1,000 rpm. The shear rate used to mitigate fouling during harvesting of microalgae typically varies between 5,000 to 90,000 s-1 and the shear stress varies between 0.6 to 29 Pa, depending on the design of the dynamic filtration system. In case of vibrating systems, a vibrating frequency of 5 Hz is capable of significantly reducing fouling.
