Reduction of long-term irreversible membrane fouling: A comparison of integrated and separated processes of MIEX and UF

Abstract

In this study, the reductions of long-term irreversible membrane fouling in integrated and separated MIEX-UF processes were explored over a prolonged experimental period. The mechanism leading to the significant difference in membrane fouling behaviors of the two processes was systematically analyzed. The results show that the chemical cleaning frequency and the rate of chemically irreversible membrane fouling formation were decreased by 50% and 49%, respectively, in the integrated process compared to the separated process. Further analysis suggested that MIEX adsorption was unrelated to the different membrane fouling behaviors between the two processes. The effect of the resin layer on filtration and backwashing was the dominate mechanism leading to the more excellent anti-fouling performance of the integrated process. The stronger adhesion force of pollutants-MIEX enable the mixed cake layer formed in the integrated process to maintain good water permeability and easy to be removed by backwashing. The adhesion force of pollutants-MIEX was significantly affected by the saturation level of resin particles and less affected by resin regeneration. During the early period of long-term filtration experiment and the initial stage after every resin replacement, the low saturation degree of resin particles guaranteed the improved effect of the resin layer always existed.