Effect of pore size and process temperature on flux, microbial reduction and fouling mechanisms during sweet whey cross-flow microfiltration by ceramic membranes

In this study, operating conditions for the cross flow microfiltration (CFMF) of sweet whey were optimised. Filtrations were performed for 65 min at 20, 40 and 50 degrees C using ceramic membranes with different nominal pore sizes (0.1, 0.5 and 0.8 mu m). Periodically, samples of whey retentate and permeate were taken and analysed for microbiological quality and physical and chemical properties. The best microbial reduction rates were achieved during filtration using a 0.1 mm membrane at 50 degrees C. The highest flux rates were achieved during filtration at 50 degrees C with all tested membranes. Fouling intensity was the lowest after filtration using a 0.5 mu m membrane at 20 degrees C. According to all results obtained, the membrane with the nominal pore size of 0.5 mu m appeared to be optimal for purposes of preserving the nutritional value, minimising membrane fouling and achieving appropriate microbiological quality of sweet whey. (C) 2014 Elsevier Ltd. All rights reserved.