Microalgal dewatering with focus on filtration and antifouling strategies: A review

Dewatering constitutes a major drawback in terms of cost and energy required to concentrate a highly diluted microalgal culture. This has hampered the economic viability of microalgal products. To this end, several technologies have been developed for harvesting microalgal biomass. Membrane technology emerges as one of the preferred harvesting and dewatering technologies in terms of low cost, simplicity of operation, energy demand and biomass recovery rate and efficiency. However, membrane fouling impedes the development and large-scale application of membrane technology. Here, we systematically reviewed and discussed the fouling phenomenon in the microalgal membrane filtration, considering the types and characteristics of foulants, the mechanism of fouling and the factors influencing membrane fouling. The state-of-the art strategies for mitigating membrane fouling are discussed, including cleaning of the fouled membrane, pretreatment of feed solution, optimization of membrane configuration and membrane surface modification. Since membrane fouling is the ultimate barrier in membrane filtration process, enhancing the fouling resistance characteristics of the membrane surface is identified and highlighted as the most promising fouling control strategy. However, more research is needed to develop durable fouling resistant membranes with enhanced stability over a long period of operation