Synergy between membrane filtration and flocculation for harvesting microalgae

Harvesting microalgal biomass using negatively charged polysulfone patterned membranes: Influence of pattern shapes and mechanism of fouling mitigation

“…For further commercialization purposes, technologies are required to reach high microalgal biomass concentrations at low cost and high efficiency. However, harvesting microalgae still remains a problem, because of the small size of the microalgal cells, the high dilution of cells in the broth and the high energy required for conventional harvesting via centrifugation (Zhao et al, 2020c;Zhao et al, 2020d). Membrane filtration processes have been seen as an alternative to harvest microalgae, due to their high microalgae retention, high harvesting efficiency, ease of upscaling and low energy input (Bilad et al, 2012b;Zhao et al, 2020d).…”

Membrane-Based Harvesting Processes for Microalgae and Their Valuable-Related Molecules: A Review

“…Thus, efficient fouling control not only requires the synthesis of enhanced tailor-made membrane materials but also of the design, operation, control and optimization of the overall process considering both the microalgal cultivation and harvesting stages. In this regard, different fouling mitigation technologies have been extensively proposed and studied in the last few years, including air-assisted backwashing technology [28,44], dynamic filtration with rotating disks [45] and vibrating systems [31,46,47], flocculation-assisted filtration [48,49], the fabrication of membranes with enhanced antifouling properties by using suitable materials, additives and synthesis methods [32,39,[50][51][52], and specific adaptations to the membrane systems, such as electric-assisted forward osmosis [53] jet-assisted MF [54], tilted panel system [55,56].…”

“…In flocculation-assisted membrane systems, the flocculation step needs to be optimized as it can affect membrane permeance and harvesting efficiency; optimized flocculant type and dossing will result in an improved filterability by giving bigger flocs and less extracellular organic matter content [48,71]. Previous studies suggested that the coagulant/flocculant type and dossing are species and membrane specific [33,48,49]. Chitosan is one of the most used flocculants, but its price significantly contributes to the total harvesting cost [70].…”

Combining patterned membrane filtration and flocculation for economical microalgae harvesting

“…Flocculation combined membrane filtration (Discart et al, 2015;Zhao et al, 2020b) can cope with the disadvantage of floccula tion (i.e. relatively low harvesting efficiency and long sedimen tation time), while flocculation can facilitate membrane separa tion by increasing particle size (i.e.…”

“…Chitosan flocculation combined with microfiltration proved highly efficient for C. sorokiniana harvesting, achieving 20-50 fold concentration (Xu et al, 2013 ). Besides, membrane fluxes and harvesting efficien cies increased with increasing chitosan dosage for C. vulgaris and Dictyosphaerium sp., indicating that the synergy between mem brane filtration and flocculation not only exists under optimal chi tosan condition, but also under sub-optimal condition (Lee et al, 2012a;Zhao et al, 2020b ). Patterned membranes have not been used yet in flocculation-assisted filtration.…”