Optimization of membrane batch processes by means of the critical flux theory

This work studies the best method for operating batch membrane processes in the presence of fouling. The case was the purification of olive washing wastewater. First, experimental work in a pilot plant consisting of a ultrafiltration and a nanofiltration process in series is reported. The critical fluxes for both operations were determined with reference to different pollutant concentrations, and the prediction equations were derived from the best fitting of the experimental results. Then the best strategy to fix the operating permeate flux rate is discussed. Adopting a permeate flux around the predicted value of the critical flux at the end of the specific membrane batch process seems to be the best procedure to assure the recovery target and extend the membrane's life.