AWWA MTC57582

Membrane fouling is regarded as a major obstacle in the use of membrane separation for water treatment. Constant transmembrane pressure experiments were evaluated in dead-end membrane filtration. The hydrodynamics of two filter cleaning methods, backwashing and air-scrubbing, were studied at a transmembrane pressure (TMP) of 1.0 kgf/cm2 since its flux was not proportional to high TMP. The method of air-scrubbing proved more effective than the method of water backwashing, which had little effect once membrane fouling occurred. It also should be noted that the shortening of intermittent physical cleaning time prevented the membranes from fouling in the case of high turbidity. On the other hand, not much flux difference was observed in the 4 ranges of constant TMP (0.15, 0.30, 0.45 and 1.0 kgf/cm2) using artificial raw water (controlled to 20 degrees Celsius). The flux declined from the initial flux of 0.529 m/hr when the transmembrane pressure was 1.0 kgf/cm2 compared with 0.30 and 0.45 kgf/cm2 TMP. As a result, during steady state performance the same flux (0.095 m/hr) was obtained in the range of 0.30 to 1.0 kgf/cm2. It is noted that flux declined quickly in the initial filtration time. Thus, 0.30 kgf/cm2 was an optimal TMP for controlling fouling under constant pressure. Includes 25 references, tables, figures.