INFLUENCE OF FILTRATION FLUX ON FOULING LAYER FORMATION IN GRAVITY-DRIVEN MEMBRANE FILTRATION

Abstract

 To develop the point-of-use water treatment by gravity-driven low-pressure membrane filtration in developing countries, we investigated the influence of membrane materials on fouling layer formation. We performed ultrafiltration experiments under the constant low-pressure using PES and PAN membranes. The resistance of fouling layers on PES membranes was one-third of that on PAN membranes. Application of the blocking model showed that cake filtration was predominant on PES membranes after second day, but the blocking model was not applicable to PAN membranes because the resistance of membrane was much higher than fouling resistance. CLSM observation and quantitative analysis of fouling layer structure showed that the fouling layer on the PES membranes had larger surface-to-volume ratio and porosity than those of the PAN membranes. These results suggested that it is preferable to utilize the high-flux membranes to mitigate membrane fouling in gravity-driven membrane filtration systems.