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Algal fouling control in a hollow fiber module during ultrafiltration by angular vibrations

Zhang, Yan, Li, Xiaolei, Xu, Rongwei, Ma, Chengwu, Wang, Xinyi, Fu, Qiang
Journal of membrane science 2019 v.569 pp. 200-208
algae, artificial membranes, energy, fouling, organic matter, quantitative analysis, ultrafiltration
In this work, a lab-scale membrane system was developed to accommodate angular vibrations with a hollow fiber module. A series of filtration experiments were designed and implemented to investigate the effects of angular vibrations on fouling by various algae-derived foulants, including algal cells, debris, extracellular organic matter (EOM), and intracellular organic matter (IOM). The experimental results indicated the effects of angular vibrations on fouling mitigation at the frequency of 2 Hz in the following order: algal cells (~ 97.4%) > debris (~ 93.6%) > IOM (~ 81.8%) > EOM (~ 52.3%). The vibrations mainly targeted the cake layer formed by these foulants, but was ineffective for pore blocking which constituted a large portion of EOM fouling. Although the fouling rates were accelerated during the normal ultrafiltration of the combined foulants, the effects of angular vibrations continued to be impressive (67.8–92.6%). This was because the cake layer formation was the dominant fouling mechanism. Furthermore, the vibrations were found to improve the organic removal by alleviating concentration polarization. In this paper, quantitative analysis is presented to demonstrate the potential of angular vibrations to control algal fouling with the relatively low energy consumption of 0.034 mW.