Minimization of membrane organic fouling and haloacetic acids formation by controlling amino sugars and/or polysaccharide-like substances included in colloidal NOM

Abstract

The objective of this study was to evaluate the effect of colloidal natural organic matter (NOM) on the disinfection by-products (DBPs) formation potentials and membrane organic fouling. From various analyses of a NOM-fouled ultrafiltration membrane surface, large amounts of colloidal NOM were found in the analyzed foulants. From FTIR spectra and pyrolysis analyses, colloidal NOMs were found to include amino sugars and polysaccharides, as indicated by N-acetyl groups in the FTIR spectra and from pyrolysis GC-mass analyses. Colloidal NOMs have two problematic aspects for membrane applications, which may induce bio-fouling due to their low biostabilities, and relatively high DBPs reactivities. The amino sugars and polysaccharides can be utilized by heterotrophic bacteria, and are identified as colloidal NOM with high fractions of biodegradable dissolved organic carbon (approximately 39%), so, their removal is expected to involve some form of biological pre-treatment process. Colloidal NOM also exhibit relatively high formation potentials of DBPs, especially haloacetic acids