Hollow Fibers and Spiral Wound Modules for Ultrafiltration of Whey: Energy Consumption and Performance

Abstract

Performances and energy consumption of pilot-scale spiral wound and hollow fiber modules were compared. The feed was cottage cheese whey acidified to pH 3 and prefiltered. Exponential flux decay behavior was typical for both units. Flux was affected by pressure in the first 60 min of operation; for the spiral wound unit, flow rate had a beneficial effect only at pressures above 135 kPa. After 3 to 5 h of operation, however, flux became independent of pressure for both modules; flow rate affected the flux of the hollow fiber module but not of the spiral wound module. The average flux of the hollow fiber unit during concentration of whey was double that of the spiral unit, but energy required for recirculation within the hollow fiber unit was higher. Compared to tubular and plate-and-frame units, the spiral and hollow fiber units consumed 10 to 100 times less energy per unit volume of permeate removed.