The effect of NOM characteristics and membrane type on microfiltration performance

Gray, Stephen R, Ritchie, C. B, Tran, Thuy and Bolto, Brian (2007) The effect of NOM characteristics and membrane type on microfiltration performance. Water Research : a Journal of the International Water Association (IWA), 41 (17). 3833 -3841. ISSN 0043-1354


Efforts to understand and predict the role of different organic fractions in the fouling of low-pressure membranes are presented. Preliminary experiments with an experimental apparatus that incorporates automatic backwashing and filtration over several days has shown that microfiltration of the hydrophilic fractions leads to rapid flux decline and the formation of a cake or gel layer, while the hydrophobic fractions show a steady flux decline and no obvious formation of a gel or cake layer. The addition of calcium to the weakly hydrophobic acid (WHA) fraction led to the formation of a gel layer from associations between components of the WHA. The dominant foulants were found to be the neutral and charged hydrophilic compounds, with hydrophobic and small pore size membranes being the most readily fouled. The findings suggest that surface analyses such as FTIR will preferentially identify hydrophilic compounds as the main foulants, as these components form a gel layer on the surface while the hydrophobic compounds adsorb within the membrane pores. Furthermore, coagulation pre-treatment is also likely to reduce fouling by reducing pore constriction rather than the formation of a gel layer, as coagulants remove the hydrophobic compounds to a large extent and very little of the hydrophilic neutral components.

Item type Article
Subjects Historical > RFCD Classification > 300000 Agricultural, Veterinary and Environmental Sciences
Historical > Faculty/School/Research Centre/Department > Centre for Environmental Safety and Risk Engineering (CESARE)
Keywords microfiltration, membranes, natural organic matter, fouling, hydrophobic and hydrophilic membranes
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