Membrane fouling during microfiltration of milk into casein and whey fractionations

Milk protein fractionation using synthetic membranes is an attractive option for the dairy industry for both environmental and economic reasons. This study aims to understand the main factors that influence and promote membrane fouling when filtering skimmed milk using a 0.1 μm PVDF polymeric membrane. Separation of whey from casein was achieved using polymeric flat sheet microfiltration (MF) membranes, but the membranes were found to be subject to fouling that doubled the total resistance. The resistance of the clean membrane was 2.0 x 10+11m-1, and that of the fouled membrane was found to be 4.6 x 10+11 m-1. This led to a progressive decline in the permeate flux, and necessitated chemical cleaning. Following an established conditioning protocol did not result in an effective removal of all of the glycerol preservative present on the membrane surface. This represented an additional fouling challenge, affecting the first filtration and cleaning cycle of the membrane life cycle.