Abstract: Operation of a membrane filter includes the step of selectively supplying gas into the compartments of a membrane unit 50 composed of an array of membrane elements 51 disposed within a treatment tank 31. A skirt element 71 is disposed at a bottom portion of the membrane unit and an aerator 61 is disposed under the skirt. A partition is also disposed at the bottom of the membrane unit forming compartments within the shirt element. The gas bubbles discharged from the aerator increase their rising force upon entry into gaps between the membranes. Because of the arrangement of the partition within the skirt element the flow rate of bubbles along the opposite side edge portions of the membrane unit can be increased having the advantage of cleaning the entire surface of each membrane, thereby preveting clogging by sludge, SS, colloid, etc. within the gaps between the membranes.

Abstract: A membrane filter apparatus includes a treatment tank; a membrane unit disposed within the treatment tank and composed of an array of membrane elements; a tubular (rectangular-tube-like) skirt element disposed at a bottom portion of the membrane unit, an aerator disposed under the skirt element for the purpose of discharging gas; a partition disposed at a bottom portion of the membrane unit and defining, together with the skirt element, a compartment within the skirt element; and a gas supply unit for supplying gas to the compartment. The gas discharged from the aerator becomes bubbles. The bubbles are supplied into and rise within the compartment, thereby increasing their rising force upon entry into gaps between membranes. Since the gas is supplied into the compartment by the gas supply unit, the flow rate of bubbles along the opposite side edge portions of the membrane unit can be increased.

Abstract: A membrane filter apparatus includes a membrane unit 50 composed of an array of membrane elements 51 disposed within a treatment tank 31. A skirt element 71 is disposed at a bottom portion of the membrane unit and an aerator 61 is disposed under the skirt. A partition is also disposed at the bottom of the membrane unit forming compartments within the skirt element. The gas bubbles discharged from the aerator increase their rising force upon entry into gaps between the membranes. Because of the arrangement of the partition within the skirt element the flow rate of bubbles along the opposite side edge portions of the membrane unit can be increased having the advantage of cleaning the entire surface of each membrane, thereby preventing clogging by sludge, SS, colloid, etc. within the gaps between the membranes. Therefore, filtration can be maintained over a longer period of time and the power required for filtration can be reduced, as well as, the frequency of manual periodic cleaning, chemical cleaning, etc.