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Influences of cellular characteristics and media properties on membrane microalgal harvesting: a comparative study using Scenedesmus acuminatus cultivated at a pilot scale

Liu, Rui, Chen, Yong, Wang, Lan, Gong, Yingchun, Zhang, Xuezhi, Park, Min Sung, Hu, Qiang
Journal of chemical technology and biotechnology 2019 v.94 no.5 pp. 1679-1689
Scenedesmus, adhesion, carbohydrates, cell aggregates, fouling, fractionation, harvesting, microalgae, organic matter, zooplankton
BACKGROUND: In order to reveal the influence of cellular characteristics and media properties on membrane microalgal harvesting, changes in the cellular characteristics and media properties of Scenedesmus acuminatus culture contaminated by microzooplankton were characterized, and their influences on membrane harvesting were compared with the control culture. Cells and algogenic organic matter (AOM) in the contaminated and control cultures were fractionated to evaluate the membrane fouling potential. RESULTS: The contaminated culture had a 32% lower average flux than control culture. Both the fractionated cells and AOM in the contaminated culture with or without concentration adjustment had higher membrane fouling potentials. Microzooplankton contamination caused more cell aggregates and transparent exopolymer particles, which formed less permeable cake layer. Increased AOM in contaminated culture contained more carbohydrates and humic/fulvic acid‐like substances, which caused a 15.5‐fold higher adhesion force between AOM and the membrane surface, and thus resulted in higher flux declining rates and lower backwashing recovery rates. CONCLUSION: Microzooplankton contamination caused the formation of cell aggregates and high concentration of AOM in S. acuminatus culture. AOM played a more important role than microalgal cells in flux declining and backwashing recovery. It is necessary to develop cultivation practice and culture pretreatment techniques to improve membrane harvesting efficiency. © 2019 Society of Chemical Industry