The influence of bubble characteristics on the performance of submerged hollow fiber membrane module used in microfiltration

This study proposed a novel submerged hollow fiber membrane module to better control membrane fouling in gas bubbling enhanced microfiltration. Using yeast as model particle in water, the performance of this module was tested by measuring the transmembrane pressure under constant flux. It was found that the nozzle size greatly affected the size and shape of created bubbles, and with the increase of the nozzle size and after exceeding one threshold value, the gas flow pattern transformed from bubble flow to the single bullet-shaped slug flow. The observed membrane fouling performance coincided with the observed two-phase flow characteristics and the results of critical flux experiments. Nevertheless, the relative efficiency of membrane fouling control by gas sparging depended on not only the nozzle size, but also the suspension concentration and gas flowrate. By limiting rising bubble around the fibers or creating slug flow, the novel module presented in this study showed some advantage over conventional submerged module in membrane fouling control.