Microalgae dewatering using forward osmosis membrane: a review

Abstract

Microalgae have attracted a considerable interest recently due to its potential in various applications, especially in renewable energy and material production industries. Microalgae harvesting technique is featured to be a valuable separation technique within the massive scale generation of bio-products derived from microalgae. Large energy consumption and cost yet poor efficacy are the major limitations of the currently available dewatering operations. Therefore, the energy efficiency and cost involved in microalgae harvesting must be improved to increase the sustainability of microalgae utilization. The use of forward osmosis (FO), an emerging membrane separation technique based on osmotic pressure, for microalgae dewatering demonstrates various benefits, for instance minimal energy consumption and high efficiency. However, FO is also challenged by several limitations, including membrane fouling, reverse draw solutes, and concentration polarization. Considerable studies have focused on providing solutions to these problems, and this paper aims to review the most important studies that have been conducted to date on microalgae dewatering. Particular attention has been made on the challenges related to the application of forward osmosis including the membrane fouling during microalgae dewatering. Several strategies have been proposed, including membrane materials, optimized module design, microalgae species and its culture environment, as well as the selection of draw solution.