AWWA MTC69699

This powerpoint presentation begins by providing a brief overview of typical foulants in water and wastewater. Research objectives were to: investigate the impact of different dissolved organic foulants on combined fouling; and, elucidate the mechanisms responsible for the enhanced flux decline during combined fouling of organic and colloidal foulants. The experimental approach included: characterizing organic-colloid and organic-membrane interactions by measuring adsorption of organic foulants on silica surface; characterizing the surface properties of the silica colloids and the membrane surface in the presence and absence of the organic foulants; and, cross-flow membrane filtration experiments. Presentation conclusions indicate the following: different dissolved organic compounds have very different effects on the fouling behavior of silica colloids; dissolved organic matter may affect colloidal deposition by modifying surface properties of the colloid and the membrane; hindered back diffusion can act as a combined fouling mechanism; and, cake layer structure may be an important factor in combined fouling. Includes figures.