Fouling behaviour during the nanofiltration of dairy ultrafiltration permeate Original Research Article

The effects of temperature and pH on the fouling behaviour of dairy ultrafiltration (UF) permeate through a nanofiltration (NF) membrane have been investigated. This has been achieved by monitoring flux curves, measuring sample mineral concentrations and via imaging of the fouled membrane surface. It has been observed that calcium phosphate is the predominant foulant leading to flux decline at various high fouling conditions, with other components including whey protein and lactose playing a lesser role. This is evidenced by the trends in bulk and soluble calcium concentration during filtration. pH has been shown to have a greater influence on flux decline than temperature, with high fouling observed for conditions of high pH.