Use of pulsating and alternating flow in cleaning-in-place (CIP) of membranes

The removal of proteinaceous deposits during membrane cleaning in the food processing industry is a time-, chemical- and energy-intensive process. The top layers formed during filtration are the result of mass transfer directed towards the membrane and the concentration polarization of retained substances, such as proteins. Depending on the filtration conditions, the membrane properties and the composition of the concentrate, protein denaturation, gelation, aggregation and protein-protein or protein-membrane interactions occur. The immediate consequence of cover-layer formation is a decrease in flux as filtration resistance increases, requiring more frequent cleaning to remove debris from the membranes. Also in the subsequent cleaning, which is a multi-step process, the capping layer leads to losses in efficiency.