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Volume 80, Number 1, January-February 2000
New applications of membrane technology in the dairy industry
Page(s) 165 - 174
DOI: 10.1051/lait:2000116

Lait 80 (2000) 165-174

Hydrodynamic factors affecting flux and fouling during ultrafiltration of skimmed milk

Alistair S. Grandison, Wirote Youravong, Michael J. Lewis

Department of Food Science and Technology, The University of Reading, Whiteknights, Reading RG6 6AP, UK


The effects of independently varying both wall shear stress ($\tau_w$) and transmembrane pressure (TMP) on permeate flux and fouling during ultrafiltration of reconstituted skimmed milk in total recycle mode have been investigated. Irreversible fouling resistance (Rif) increased as TMP increased. Increasing $\tau_w$ at constant TMP led to an increase in both the initial flux, and subsequent flux decline, and to a decrease in Rif. At the highest $\tau_w$, increasing TMP resulted in greater initial flux accompanied by increasing rates of flux decline and more irreversible fouling. Increasing and then decreasing TMP in a controlled, stepwise manner at constant $\tau_w$ suggested that flux is governed by both a reversible, and an irreversible fouling layer which forms at higher TMP; this also controlled the transmission of protein. Critical operating conditions producing the least fouling were evaluated during this procedure.

ultrafiltration / fouling / critical flux / wall shear stress

Correspondence and reprints: A.-S. Grandison

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