Abstract: A submerged membrane separator includes: a plurality of membrane cartridges arranged at predetermined spaces; a flow generating device for generating flows in one direction along the membrane surfaces of the membrane cartridges; and wall members on both sides of a channel of the flow in the one direction formed between the membrane cartridges adjacent to each other. The membrane cartridges can be attached and detached from another direction substantially orthogonal to the flows in the one direction and substantially orthogonal to the arrangement direction of the membrane cartridges.

Abstract: A submerged membrane separator 31 includes: a casing 33 opened at the top; a plurality of flat membrane cartridges 34 arrayed at intervals in the casing 33; and an air diffuser 36 provided below the membrane cartridges 34. The membrane cartridges 34 are movably held in the up-down direction in the casing 33 while having a space ? in the up-down direction. Lifting suppressing members 63a and 63b for restricting a lifting amount of the membrane cartridges 34 during filtration operation to be smaller than the space ? in the up-down direction are provided in the casing 33.

Abstract: Disclosed is a membrane cartridge used in a submerged membrane separator. A peripheral portion of a filtration membrane is joined to the surface of a filtration plate. A portion higher than the surface of the filtration plate corresponding to the peripheral edge of the filtration membrane is formed on the surface of the filtration plate further on the outer side than the peripheral edge of the filtration membrane.

Abstract: A water treatment system having a biological treatment step (a secondary treatment step) and a membrane separation step (a tertiary treatment step), wherein a portion of the raw water to be treated and/or a portion of the primarily treated water in the pretreatment step are biologically treated and supplied into a reaction tank in the membrane separation step as the main channel system, while the remainder the raw water to be treated and/or the remainder of the primarily treated water in the pretreatment step are added together with a flocculating agent to the reaction tank in the membrane separation step, and then the membrane separation is conducted in the membrane separation step.

Abstract: A submerged membrane separator includes: a plurality of membrane cartridges arranged at predetermined spaces; a flow generating device for generating flows in one direction along the membrane surfaces of the membrane cartridges; and wall members on both sides of a channel of the flow in the one direction formed between the membrane cartridges adjacent to each other. The membrane cartridges can be attached and detached from another direction substantially orthogonal to the flows in the one direction and substantially orthogonal to the arrangement direction of the membrane cartridges.

Abstract: Disclosed is a membrane cartridge used in a submerged membrane separator. A peripheral portion of a filtration membrane is joined to the surface of a filtration plate. A portion higher than the surface of the filtration plate corresponding to the peripheral edge of the filtration membrane is formed on the surface of the filtration plate further on the outer side than the peripheral edge of the filtration membrane.

Abstract: A submerged membrane separator 31 includes: a casing 33 opened at the top; a plurality of flat membrane cartridges 34 arrayed at intervals in the casing 33; and an air diffuser 36 provided below the membrane cartridges 34. The membrane cartridges 34 are movably held in the up-down direction in the casing 33 while having a space ? in the up-down direction. Lifting suppressing members 63a and 63b for restricting a lifting amount of the membrane cartridges 34 during filtration operation to be smaller than the space ? in the up-down direction are provided in the casing 33.

Abstract: A water treatment system having a biological treatment step (a secondary treatment step) and a membrane separation step (a tertiary treatment step), wherein a portion of the raw water to be treated and/or a portion of the primarily treated water in the pretreatment step are biologically treated and supplied into a reaction tank in the membrane separation step as the main channel system, while the remainder the raw water to be treated and/or the remainder of the primarily treated water in the pretreatment step are added together with a flocculating agent to the reaction tank in the membrane separation step, and then the membrane separation is conducted in the membrane separation step.

Abstract: A large scale membrane separating installation wherein a cleaning chemical liquid flows to membrane units through a header and branch pipes. A cleaning chemical liquid distribution unit comprises the header and the branch pipes having a diameter smaller than that of the header. The cleaning chemical liquid distribution unit comprises a pipeline configuration uniformly distributing the cleaning chemical liquid supplied to the membrane units.

Abstract: A multistage immersion type membrane separator in which an air diffuser is disposed under a filtration part immersed in a treatment tank, characterized in that: the filtration part has plural plate-like membrane cartridges arranged in a vertically parallel multistage fashion at spaced intervals for forming a crossflow passage of a predetermined width; and that the air diffuser has a diffuser tube disposed sidewardly that is communicated at its basal end to an air supply source and has at its lower side part plural blowholes, a flushing pipe that is communicated at its basal end to the tip of the diffuser tube and has at its tip an opening serving as an outlet above the diffuser tube, and a flushing valve disposed in the flushing pipe.

Abstract: An air diffuser (2) having a diffuser tube (5) immersed sidewardly in a tank (1), a flushing pipe (9) opening at its tip an outlet (11) at an upper position of the diffuser tube, and a flushing valve (12) disposed in the flushing pipe (9). The diffuser tube (5) is made up of a main pipe (6) communicated at its basal end to an air supply source (8) and communicated at its tip to the flushing pipe (9), and a plurality of branch pipes (7) being communicated to the main pipe (6) and opening at their tip as a blowhole (10) at a lower position of the main pipe (6). During air diffusion, air is supplied from the air supply source (8) with tile flushing valve (12) closed, and the air is diffused from the blowholes (10). During flushing, air is supplied from the air supply source (8) with the flushing valve (12) opened and an intra-tank mixed liquor is sucked from the openings of the diffuser tube (5), thereby flushing the inside of the diffuser tube (5) with the sucked intra-tank mixed liquor.

Abstract: A multistage immersion type membrane separator (22) in which an air diffuser (24) is disposed under a filtration part (23) immersed in a treatment tank (21), characterized in that: the filtration part has plural plate-like membrane cartridges (26) arranged in a vertically parallel multistage fashion at spaced intervals for forming a crossflow passage of a predetermined width; and that the air diffuser (24) has a diffuser tube disposed sidewardly that is communicated at its basal end to an air supply source (34) and has at its lower side part plural blowholes, a flushing pipe (33) that is communicated at its basal end to the tip of the diffuser tube and has at its tip an opening serving as an outlet (33a) and locating at an upstream of the diffuser tube, and a flushing valve (35) disposed in the flushing pipe (33).

Abstract: An air diffuser (2) comprises a diffuser tube (5) immersed sidewardly in a tank (1), a flushing pipe (9) opening at its tip an outlet (11) at an upper position of the diffuser tube, and a flushing valve (12) disposed in the flushing pipe (9). The diffuser tube (5) is made up of a main pipe (6) communicated at its basal end to an air supply source (8) and communicated at its tip to the flushing pipe (9), and a plurality of branch pipes (7) being communicated to the main pipe (6) and opening at their tip as a blowhole (10) at a lower position of the main pipe (6). During air diffusion, air is supplied from the air supply source (8) with tile flushing valve (12) closed, and the air is diffused from the blowholes (10). During flushing, air is supplied from the air supply source (8) with the flushing valve (12) opened and an intra-tank mixed liquor is sucked from the openings of the diffuser tube (5), thereby flushing the inside of the diffuser tube (5) with the sucked intra-tank mixed liquor.

Abstract: Provided is a submerged membrane cartridge which comprises a supporting plate made of a resin, and a membrane disposed so as to cover the surface of the supporting plate, and is characterized in that the membrane is fused in a plurality of welding allowances formed in multiple, along the entire periphery of the supporting plate; an inner fixing portion that retains the membrane under tension is formed by an inner welding allowance; a water sealing portion that ensures a sealing function through the entire periphery of the membrane is formed by a central welding allowance; and an outer fixing portion that fixes the periphery of the membrane to the supporting plate is formed by an outer welding allowance.