Design of an integrated membrane system to produce dairy by‐product from waste processing

Abstract

SummaryMembrane technology is used in different applications. In this work, a whey‐based product with a final protein content of 16% has been formulated from Scotta – the last waste of the dairy industry – by cross‐flow ultrafiltration (UF) membrane followed by vacuum evaporation (EV). Until now, Scotta was only revalorized in conjunction with whey and into the biogas production process. It was never revalorized as food in the food supply chain. UF and EV processes led to an overall water amount removed from the whey of 84.9%. A vertical configuration of the polyethersulfone (PES) hollow‐fibre membrane was used in the OUT‐to‐IN structure. At 1.50 bar of pressure with 120 min of time interval, higher permeate flow decay has been obtained with a further reduction of the microbiological environments. A combination of intermediate and standard blocking seems to happen in all membranes, but concentration polarisation (CP) may be neglected for membranes with high fibres. The best EV operating conditions have been obtained at ten bars, with 37°C of the heating bath and 2.5 h of time, further preventing microorganism formation and protein denaturation. For future applications of Scotta revalorized in a food, it would be interesting to investigate the use of the multistage methods of membrane and evaporators to obtain a low specific energy consumption and to reduce costs further.