Back-pulsing as an energy-saving method in the microfiltration of milk

Extended shelf-life milk can be produced by a combination of microfiltration and pasteurisation. However, due to the need for high cross-flow velocity during microfiltration, the energy consumption is high. One way of decreasing the energy demand during microfiltration is to use back-pulsing for fouling control. Microfiltration was performed in constant flux mode on skim milk to measure the fouling rate. Different frequencies and durations of back-pulsing were investigated to determine the optimal conditions. The most promising conditions were used to evaluate the degree to which the cross-flow velocity could be decreased without significantly affecting the performance of the membrane. It was found that short pulses (0.2 s) at a frequency of 1 min−1 were most efficient, and the membrane performance was only slightly affected by reducing the cross-flow velocity from 5.8 m s−1 to 4.5 m s−1 with back-pulsing. This corresponds to a reduction in the energy requirement of 50%.