Concentration of skim milk by means of dynamic filtration using overlapping rotating ceramic membrane disks

This paper focuses on the microfiltration (0.06 μm pore size) of pasteurised skim milk (3.4%, w/w, protein) using a pilot-plant scale dynamic filtration system with overlapping membrane and metal blind disks (DCF system). Concentration tests at a rotational speed of 1000 min−1 and transmembrane pressures (TMP) between 64 and 282 kPa resulted in initial fluxes between 57.8 ± 2.1 and 74.7 ± 2.8 L m−2 h−1, respectively. The highest maximum volume reduction ratio (VRR), calculated by logarithmic extrapolation to zero flux, was found to be 9.0 ± 0.3; a value comparable with a dynamic filtration system with non-overlapping membrane disks (MSD separator system). The average shear stress over the membrane surface was calculated to be 512 Pa, to compare the MSD separator and the DCF system. The DCF system could preferably be applied in small scale manufacture of milk retentates for protein contents of ≥14.8% (w/w).