Nanofiltration Operating Conditions and Fouling Challenges in Drinking Water Treatment

Two types of Nanofiltration membranes had been used to study the influence of cross flow velocity on biofouling. Filtration had been conducted at constant transmembrane pressure of 5 bars and variable cross flow velocity (0.02, 0.06, 0.15 and 0.39 ms-1). The higher cross flow velocity had decreased the rate of fouling in the order of 1.3, 1.5 and 1,6 for NF90 membrane and 1.8, 2 and 4.33 for NF270, while the achieved reduction in the concentration of the active biomass on the membrane surface had reached the order of 1.4, 1.68 and 1.65 for NF90 and 2.2, 1.64, and 1.98 respectively for NF270. The impact of the particles load was more severe in the last section of the membranes due to the reduction in the particles size and the increase in the particles count, while the cross flow velocity higher than 0,06 ms-1 had minor influence on the bioparticles removal rate comparatively to non bioparticles.