Modeling Formation of Natural Organic Matter Fouling Layers on Ultrafiltration Membranes

Abstract

Three simple mathematical models to describe fouling of an ultrafiltration membrane by natural organic matter (NOM) are developed and compared. These models attribute the fouling to: (1) an increase of the effective pore length by an amount equal to the thickness of the NOM gel layer that forms on the membrane surface; (2) formation of a uniform, microporous NOM gel layer on the membrane surface, made of primary particles comprising tens to hundreds of NOM molecules; or (3) narrowing of the membrane pores by sorption of a monolayer of NOM molecules along the full length of each pore. The key parameters characterizing each model are identified and estimated based on data for flux and film growth gathered in the same system. In each case, the estimated parameter values are plausible in light of the known physical properties of the membrane and NOM molecules.