Fouling and cleaning of whey protein concentrate fouled ultrafiltration membranes

Ultrafiltration membranes are used extensively in dairy industry. The formation of fouling deposits during processing of dairy fluids has a significant impact on the performance of these membranes. In the current study, performance of a 30 kDa membrane has been investigated which is used to process reconstituted whey protein concentrate. The increase in solution concentration is observed to have a varying impact on the permeate flux. 0.2 wt% caustic solution gives the best performance for cleaning the fouled membranes.

The performance of 30 kDa ultrafiltration membranes was investigated during the process- ing of whey protein concentrate solution. The membranes suffered significant fouling and the permeate flux reduced by up to 85%. Increasing the solution concentration not only provided higher driving force for the deposit formation it also enhanced the deposit removal due to increased viscosity. Also there were changes in in- ter-molecular interactions. 2 wt% solution resulted in lower permeate flux compared with 1 wt% solution. However, increasing the concentration to 3 wt% enhanced the flux rate. This possibly could be attributed to comparatively larger increase in the removal rate compared with the deposit rate. Cleaning of the fouled membranes with caustic solution allowed the recovery of most of the membrane flux. 0.2 wt% caustic solution was observed to provide the best performance compared with 0.3 wt % and 0.5 wt% solutions. The higher concentration solutions probably enhanced the swelling of the deposits which consequently resulted in additional blockage of the pores and the permeate flux recovery was not as high.