Effect of operating parameters and modes in the filtration of acid whey using ultra- and microfiltration ceramic membranes

Whey is a liquid by-product obtained by cheese elaboration, which is not completely used due to the large quantities produced. As a result, the whey is poured into rivers and soils and becomes a pollutant agent. The valorization of acid whey using membrane clarification was evaluated, where the effect of temperature and membrane cut-off were studied using acid whey. Permeability was three times higher at 70 degrees C than 50 degrees C (163.2 +/- 11.1 y 62.4 +/- 9.2 L/m2.h, respectively) for membranes with a cut-off of 0.2 mu m. Furthermore, the permeate flux for this cut-off was three, six and ten times higher compared with the cut-off of 300, 150 y 50 kDa at 70 degrees C, respectively. The clarification stage was scaled-up with 0.2 mu m membranes, achieving about 22 L of whey filtered for Batch mode until a volume reduction factor (VRF) of 5 with protein retention of 68%. In Fed-Batch mode, the retention of protein was 61%, but the filtration could be carried out for longer, reducing fouling and filtering almost the double of the quantity of whey compared with Batch mode. In all cases, the turbidity of permeates was lower than 12 NTU (reduction >99%), regardless of whey turbidity whose values might be superior to 12,000 NTU.