Identification and control of fouling of low-pressure (MF and UF) membranes by drinking-water natural organic matter

Natural organic matter (NOM) is responsible for organic fouling during membrane filtration. Flux decline can be affected by the characteristics of the NOM and its interaction with membranes and their associated properties. The results showed that serious flux decline observed for MF membranes may be caused by pore blockage associated with large (macromolecular) hydrophilic molecules. In the case of UF membranes, flux decline may be caused by sequential or simultaneous processes such as cake/gel formation with large (macromolecular) molecules and pore blockage with relatively smaller molecules during filtration. The flux decline tests with representative macromolecules showed that fouling was affected more by the physical characteristics (e.g. size and structure (shape)) of foulants than the characteristics (e.g. hydrophilicity) of foulants.