Comparison of aeration effect between pressure-driven and thermal membrane processes.

Microporous membranes have been widely used in various water treatment systems, including pressure-driven separation processes such as microfiltration (MF) and ultrafiltration (UF) and thermally-driven separation processes such as membrane distillation (MD). However, control of membrane fouling is key to the successful design and operation of these processes. In this study, the effect of aeration on the fouling control was investigated in MF and MD processes, which have different driving forces. Experiments were carried out using the same microporous membranes in MF and MD processes to compare the difference in fouling propensity and the antifouling effect by the aeration. The reversibility of the foulants deposited on the membrane was also compared. Hermia’s fouling models were applied to analyze the aeration effect in both MF and MD but failed to fit the experimental data in most cases. Accordingly, a novel fouling model was suggested and used to interpret the experimental results. The specific fouling potential (φ) was introduced to show how the fouling potential changes during the operation of the membrane processes. It was confirmed from this analysis that the aeration effect was different between MF and MD, which is attributed to the inherent difference in the driving forces. [ABSTRACT FROM AUTHOR]