Abstract: A membrane separation type activated sludge treatment method according to an aspect of the present invention includes a step of performing biological treatment on waste water and a step of performing membrane separation on water having been treated in the biological treatment step. The membrane separation step employs a plurality of filtration modules including a plurality of hollow fiber membranes arranged adjacent to one another and oriented in one direction and a pair of holding members fixing both ends of the plurality of hollow fiber membranes, and a plurality of cleaning modules supplying air bubbles from beneath the filtration modules. An amount of treated water sucked by the filtration modules and an amount of air bubbles supplied by the cleaning modules are varied in response to variations in an inflow rate of the waste water in the biological treatment step.

Abstract: An object of the present invention is to provide a filter unit in which hollow fiber membranes can be effectively cleaned. A filter unit of the present invention includes a plurality of filtration modules and one or more air bubble generation modules that supply bubbles to the filtration modules from below. Each filtration modules includes a plurality of hollow fiber membranes extending in an up-down direction and arranged side by side in a curtain shape and which are arranged at intervals. The one or more air bubble generation modules supply coarse bubbles to the filtration modules.

Abstract: The present invention provides intermittent-bubbling equipment used while being immersed in a liquid. The intermittent-bubbling equipment includes a tubular casing vertically disposed; and a plurality of partition walls disposed substantially parallel to an axial direction in the casing, and configured to define a gas introducing chamber, a gas inducing chamber, and a gas discharging chamber. The gas introducing chamber and the gas inducing chamber communicate with each other at a top of the casing, and the gas inducing chamber and the gas discharging chamber communicate with each other at a bottom of the casing. An upper side of the gas introducing chamber and an upper side of the gas inducing chamber are closed by a lid plate, and a lower side of the gas inducing chamber and a lower side of the gas discharging chamber are closed by a bottom plate. A cross-sectional area of the gag introducing chamber may be greater than a cross-sectional area of the gas discharging chamber.

Abstract: A method for operating a filtration apparatus according to an aspect of the present invention is a method for operating a filtration apparatus including three or more filtration modules, the method including a filtration step in which a filtration treatment is performed using the filtration modules and a cleaning step in which some of the filtration modules are stopped from performing the filtration treatment and the filtration modules stopped from performing the filtration treatment are cleaned simultaneously. A filtration apparatus according to another aspect of the present invention is a filtration apparatus including three or more filtration modules, a collection system that collects a filtrate from the filtration modules, and a cleaning system that cleans some of the filtration modules simultaneously.

Abstract: An aeration tube according to the present invention, which is configured to supply a cleaning gas for a filtration unit, includes a straight tubular aeration portion, into one end of which the cleaning gas is force-fed and which has a plurality of aeration holes, and a tubular solid content discharge portion which extends from another end of the aeration portion. In a vertical cross section including a central axis of the aeration portion, a central axis of a discharge side of the solid content discharge portion is inclined downward with respect to the central axis of the aeration portion, and an angle of inclination of the central axis of the discharge side with respect to the central axis of the aeration portion is 20° to 80°. Preferably, the aeration holes are arranged on an upper side of the aeration portion, and centers of the aeration holes coincide with the vertical cross section including the central axis of the aeration portion.

Abstract: A membrane separation type activated sludge treatment method according to an aspect of the present invention includes a step of performing biological treatment on waste water and a step of performing membrane separation on water having been treated in the biological treatment step. The membrane separation step employs a plurality of filtration modules including a plurality of hollow fiber membranes arranged adjacent to one another and oriented in one direction and a pair of holding members fixing both ends of the plurality of hollow fiber membranes, and a plurality of cleaning modules supplying air bubbles from beneath the filtration modules. An amount of treated water sucked by the filtration modules and an amount of air bubbles supplied by the cleaning modules are varied in response to variations in an inflow rate of the waste water in the biological treatment step.

Abstract: A filter unit according to the present invention includes a plurality of filtration modules and a plurality of air bubble generation modules. Each filtration module includes a plurality of hollow fiber membranes extending in an up-down direction and arranged side by side in a curtain shape and a pair of holding members to which top and bottom ends of the hollow fiber membranes are fixed. The air bubble generation modules discharge bubbles toward the hollow fiber membranes. The filtration modules are arranged in parallel at intervals. each air bubble generation module has a discharge port that is disposed between lower holding members of a pair of adjacent filtration modules and above bottom ends of the lower holding members.

Abstract: A method of operating a filtration apparatus according to the present invention is a method of operating a filtration apparatus which includes one or more filtration modules provided with a plurality of hollow-fiber membranes arranged in parallel in one direction and a pair of holding members configured to fix both ends of the plurality of hollow-fiber membranes, and one or more cleaning modules configured to supply bubbles from below the filtration modules, the method including an operation step of carrying out a filtration treatment with the filtration modules, and a cleaning step of cleaning the filtration modules while stopping the filtration treatment with the filtration modules for 0.25 to 3 hours. The cleaning step is performed at intervals of 12 to 72 hours.

Abstract: A membrane separation type activated sludge treatment method according to an embodiment of the present invention includes a step of performing biological treatment on waste water; and a step of performing membrane separation after the biological treatment step, wherein the membrane separation step is performed with a plurality of filtration modules including a plurality of hollow fiber membranes arranged adjacent to one another and oriented in one direction and a pair of holding members fixing both ends of the plurality of hollow fiber membranes, and a number of the filtration modules operated is changed in accordance with variations in an inflow rate of waste water in the biological treatment step.

Abstract: A filtration apparatus according to an embodiment of the present invention includes at least one filtration module including a plurality of hollow-fiber membranes arranged by being pulled in one direction and a pair of holding members that fix both ends of the plurality of hollow-fiber membranes, and at least one cleaning module that supplies air bubbles from below the filtration module. In the filtration apparatus, the filtration module has a structure in which the plurality of hollow-fiber membranes are arranged to form a curtain-like shape on the holding members each having a shape of a bar, and the holding members each have a plurality of regions in which the plurality of hollow-fiber membranes are densely arranged and which are disposed at intervals in a longitudinal direction.

Abstract: A filtration unit includes a plurality of filtration modules and a piping unit. Each filtration module includes a plurality of hollow fiber membranes extending in a vertical direction and arranged side by side in a form of a plate, and a first water collector having a linear shape that is connected to upper openings of the hollow fiber membranes and through which filtered liquid that has permeated into each hollow fiber membrane flows. The piping unit is connected to the first water collectors of the filtration modules. The filtration modules are arranged in two rows and in a striped pattern in each row. The piping unit includes two combining pipes that are arranged parallel to each other and that are connected to outer end portions of the first water collectors of the filtration modules in each row by first connection pipes.

Abstract: A filtration module according to one embodiment of the present invention includes plural hollow fiber membranes held while being aligned in one direction and a pair of holding members that fix both ends of the hollow fiber membranes. In the holding members, an existence region where the hollow fiber membranes exist has a rectangular shape in a direction perpendicular to the direction in which the hollow fiber membranes are aligned. The hollow fiber membranes are arranged in a matrix in a long side direction and a short side direction of the existence region. In the existence region, a ratio of an average pitch of the hollow fiber membranes in the long side direction to an average pitch of the hollow fiber membranes in the short side direction is 1.2 or more and 2.5 or less.

Abstract: A filtration module according to an embodiment of the present invention includes a plurality of hollow fiber membranes held while being aligned in one direction and a pair of holding members that fix both ends of the hollow fiber membranes. In the holding members, an existence region where the hollow fiber membranes exist has a rectangular shape in a direction perpendicular to the direction in which the hollow fiber membranes are aligned; a ratio of an average length of the existence region in a long side direction to an average length of the existence region in a short side direction is 10 or more and 50 or less; an average outer diameter of the hollow fiber membranes is 1 mm or more and 6 mm or less; and a ratio of an average effective length of the hollow fiber membranes between the holding members to the average length of the existence region in the short side direction is 40 or more and 200 or less.

Abstract: A filtration apparatus and an immersion-type filtration method using the same having excellent treatment efficiency and cost performance are provided. The filtration apparatus of the present invention is an immersion-type filtration apparatus that purifies a liquid to be treated by using a filtration membrane, and includes a plurality of filtration units each including a filtration vessel and at least one filtration membrane module immersed in the filtration vessel, the filtration units being arranged in series. The liquid to be treated is preferably supplied from an upstream filtration unit to a downstream filtration unit of the filtration apparatus by causing the liquid to be treated to overflow. An air bubble supplying unit that supplies air bubbles from under the filtration membrane module is preferably provided.

Abstract: An object is to provide a filtration apparatus which can be reduced in size by relatively densely arranging a plurality of filtration modules and in which the efficiency of cleaning the hollow-fiber membranes can be increased. A filtration apparatus according to the present invention includes a plurality of filtration modules, each including a plurality of hollow-fiber membranes, which are arranged in parallel in a vertical direction so as to form a substantially curtain-like shape, and a pair of rod-shaped holding members that secure top and bottom ends of the hollow-fiber membranes; one or more cleaning modules that supply bubbles to the filtration modules from below; and a frame that holds the filtration modules and the one or more cleaning modules. The filtration modules are arranged in parallel and with substantially constant intervals therebetween.

Abstract: An object is to provide an intermittent-bubbling device that can generate a bubble having a large diameter and that can be suitably used for, for example, claiming a filtration module. The present invention provides an intermittent-bubbling device used while being immersed in a liquid, and formed from a series of tubes, the intermittent-bubbling device including a gas storage path, one end of which opens downward, which stores a predetermined amount of gas, and which has a substantially inverted U-shape, and a gas-guiding path that communicates with the other end of the gas storage path, and that guides the gas upward from the other end. Preferably, a highest point at a lowest position of the gas-guiding path is not lower than the other end of the gas storage path. A cross-sectional area on the one end side of the gas storage path at a horizontal level position horizontal to the other end of the gas storage path is preferably larger than a cross-sectional area of the gas-guiding path.

Abstract: The present invention provides intermittent-bubbling equipment used while being immersed in a liquid. The intermittent-bubbling equipment includes a tubular casing vertically disposed; and a plurality of partition walls disposed substantially parallel to an axial direction in the casing, and configured to define a gas introducing chamber, a gas inducing chamber, and a gas discharging chamber. The gas introducing chamber and the gas inducing chamber communicate with each other at a top of the casing, and the gas inducing chamber and the gas discharging chamber communicate with each other at a bottom of the casing. An upper side of the gas introducing chamber and an upper side of the gas inducing chamber are closed by a lid plate, and a lower side of the gas inducing chamber and a lower side of the gas discharging chamber are closed by a bottom plate. A cross-sectional area of the gag introducing chamber may be greater than a cross-sectional area of the gas discharging chamber.

Abstract: The invention offers a filtration apparatus having excellent capability to clean the surface of hollow-fiber membranes and being able to maintain high filtration capability and an immersion-type filtration method using the filtration apparatus. The invention is a filtration apparatus that is an immersion type and that is provided with both a filtration module having multiple hollow-fiber membranes held in a state in which they are arranged by being pulled unidirectionally and a gas supplier that supplies gas bubbles from under the filtration module. In the filtration apparatus, each of the gas bubbles supplied by the gas supplier is divided into a plurality of gas bubbles after colliding against the filtration module. It is desirable that the gas bubbles supplied by the gas supplier have an average horizontal diameter larger than the maximum spacing of holding portions in the multiple hollow-fiber membranes in the filtration module.

Abstract: The present invention provides a filtration device comprising a filtration tank that stores a liquid to be treated, the liquid containing a microorganism; an immersion-type filtration module that is disposed in the filtration tank and that includes a plurality of separation membranes; and a first gas supply unit that generates bubbles for cleaning the separation membranes from below the immersion-type filtration module. The filtration device further includes a second gas supply unit that is arranged in a lower portion of the filtration tank so as to be spaced apart from the first gas supply unit and that generates bubbles for supplying oxygen. A bubble-rising prevention zone is formed above the second gas supply unit by the generation of the bubbles from the first gas supply unit. A downflow of the liquid to be treated is preferably present in the bubble-rising prevention zone. A turbulence flow of the liquid to be treated may be present in the bubble-rising prevention zone.

Abstract: A filtration device includes a tubular body having an inlet and an outlet for a solution to be treated, and a plurality of hollow fiber membranes aligned in the tubular body. By creating a difference in pressure between the outside and inside of the hollow fiber membranes, water in the solution to be treated is passed from the outside to the inside. The filtration device further includes a gas supply unit configured to supply a bubble from below the plurality of hollow fiber membranes. The tubular body has a gas discharge port above the inlet and the outlet. The gas discharge port is provided for discharging the bubble supplied from the gas supply unit to the outside.