JP2017196600A - Hollow fiber membrane cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow fiber membrane cassette which can be compact and lightweight, and can be pulled up easily from a water tank.SOLUTION: A hollow fiber membrane cassette 10 includes a plurality of hollow fiber membrane elements 11, and a frame 21 for holding the hollow fiber membrane elements 11. The hollow fiber membrane element 11 includes a hollow fiber membrane bundle 14, a first housing on which a first end part in a length direction of the hollow fiber membrane 13 of the hollow fiber membrane bundle 14 is fixed, and a second housing 16 on which a second end part in the length direction of the hollow fiber membrane 13 of the hollow fiber membrane bundle 14 is fixed. The frame 21 includes a first vertical member 22 on which the first housing is fixed, a second vertical member 23 on which the second housing 16 is fixed, an aeration tube 24 which connects lower parts of the first vertical member 22 and the second vertical member 23, and an upper horizontal member 25 which connects upper parts of the first vertical member 22 and the second vertical member 23.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hollow fiber membrane cassette in which a hollow fiber membrane element and an air diffuser are integrated.

  As a method of treating various wastewater (industrial wastewater, domestic wastewater, etc.) containing organic matter, microorganisms (bacteria, etc.), their debris, etc. There is known a membrane separation activated sludge method in which sludge and treated water are separated into solid and liquid by a membrane unit immersed in the water. Further, in the process of producing drinking water from rivers, lakes, groundwater, etc., a membrane separation method that can reliably perform turbidity / sterilization of water to be treated by a membrane unit is known as advanced treatment.

  As a membrane unit, a device including a membrane module in which a plurality of membrane elements are arranged inside, and an air diffuser having a plurality of air diffusers arranged below the membrane module is known (for example, a patent) Reference 1).

  In the membrane unit, membrane clogging or membrane breakage, obstruction of the air diffuser, and the like may occur, and therefore maintenance needs to be performed regularly or temporarily. At the time of maintenance, it is necessary to pull up the entire membrane unit from the aquarium with heavy machinery and equipment such as cranes, so it costs money to prepare heavy machinery and equipment such as cranes.If the aquarium is indoors, There is a problem that the ceiling is high or the building needs to be open.

As a membrane unit that can take out and replace a defective membrane element, the following has been proposed.
(1) A hollow fiber membrane unit including a rack type hollow fiber membrane module in which a cassette type hollow fiber membrane element can be taken out in a horizontal direction and an air diffuser (Patent Document 2).

In addition, as a membrane module in which a membrane element and a diffuser tube (aeration unit) are integrated without providing an air diffuser separately from the membrane module, the following has been proposed.
(2) A flat membrane module including a flat membrane element provided with a diffuser at a lower portion of the flat membrane and a frame for holding the flat membrane element (Patent Document 3).
(3) A flat membrane module in which a flat membrane cassette having a flat membrane element provided with a flat membrane in a frame body and a diffuser tube connected to the frame body is accommodated in a casing so as to be freely removable in the vertical direction (Patent Document 4).

JP 2007-152179 A Special table 2003-513784 gazette JP-A-9-299951 JP-A-10-296253

  However, when the hollow fiber membrane element is maintained in the membrane unit (1), the hollow fiber membrane element cannot be taken out in the water tank when the water tank is narrow because the hollow fiber membrane element is taken out in the horizontal direction. Therefore, it is necessary to pull up the hollow fiber membrane unit from the water tank with a heavy machine such as a crane and equipment. Also, when performing maintenance of the air diffuser, it is necessary to pull up the hollow fiber membrane unit from the water tank with a heavy machine such as a crane, equipment or the like.

  The flat membrane element has a smaller membrane area per unit volume than the hollow fiber membrane element. Therefore, the flat membrane element needs to be larger than the hollow fiber membrane element in order to have the same membrane area as the hollow fiber membrane element. Therefore, the flat membrane module (2) is also large, and when performing maintenance, it is necessary to pull the flat membrane module out of the water tank with a heavy machine such as a crane or equipment. In addition, since the strength of the diffuser is weak, a member (lower part of the frame) for maintaining the strength of the lower part of the flat membrane element is required separately from the diffuser, and the flat membrane module becomes heavier and the cost of the member Also take extra.

  The flat membrane cassette in the flat membrane module (3) is also large for the same reason as the flat membrane module in (2). When performing maintenance, the flat membrane cassette needs to be lifted from the water tank by a heavy machine such as a crane or equipment. There is. Further, since the water collecting pipe of the flat membrane element is provided on the upper frame of the frame body, the upper frame becomes wide and sludge or the like is likely to accumulate on the upper frame. Therefore, sludge or the like accumulated on the upper frame closes the gaps between the flat membrane elements, making it difficult for air from the air diffuser to pass between the flat membrane elements, and membrane clogging easily occurs. In addition, sludge accumulated on the upper frame is entangled with the adjacent flat membrane element, making it difficult to remove the flat membrane cassette from the casing.

  The present invention provides a hollow fiber membrane cassette that can be made compact and lightweight and can be easily pulled up from a water tank.

The present invention has the following aspects.
<1> A hollow fiber membrane cassette including a plurality of hollow fiber membrane elements and a frame for holding the hollow fiber membrane element; the hollow fiber membrane element is formed by aligning a plurality of hollow fiber membranes in one direction. A hollow fiber membrane bundle, a first housing to which a first end of the hollow fiber membrane bundle in the length direction of the hollow fiber membrane is fixed, and a length of the hollow fiber membrane of the hollow fiber membrane bundle A second housing having a second end in the direction fixed; the frame has a first longitudinal member to which the first housing of the hollow fiber membrane element is fixed; and the hollow fiber membrane A second vertical member to which the second housing of the element is fixed, an air diffuser pipe connecting lower portions of the first vertical member and the second vertical member, the first vertical member and the first An upper horizontal member for connecting upper portions of two vertical members to each other, Fiber membrane cassette.
<2> The hollow fiber membrane element is a rectangular hollow fiber membrane element having a sheet-like hollow fiber membrane bundle and a tubular first housing and a second housing extending in the vertical direction; A vertical member is fixed to a first upper assembly block to which upper ends of the first housings of the plurality of hollow fiber membrane elements are fixed, and lower ends of the first housings of the plurality of hollow fiber membrane elements are fixed. A first lower assembly block; wherein the second longitudinal member has a second upper assembly block to which upper ends of the second housings of the plurality of hollow fiber membrane elements are fixed; and The hollow fiber membrane cassette according to <1>, further including a second lower assembly block to which lower ends of the second housings of a plurality of hollow fiber membrane elements are fixed.
<3> The hollow fiber membrane cassette according to <1> or <2>, wherein an interval between adjacent hollow fiber membrane elements is 1 mm or less at a closest position.
<4> The hollow fiber membrane cassette according to any one of <1> to <3>, wherein the length in the longitudinal direction is 1 m or less.
<5> The hollow fiber membrane cassette according to any one of <1> to <4>, wherein the mass in a wet state is 30 kg or less.

  The hollow fiber membrane cassette of the present invention can be made compact and lightweight, and can be easily pulled up from the water tank.

It is a perspective view which shows an example of a hollow fiber membrane cassette. It is sectional drawing of the hollow fiber membrane cassette of FIG. It is a front view which shows an example of a hollow fiber membrane element. It is a perspective view which shows the other example of a hollow fiber membrane cassette. It is a perspective view which shows the other example of a hollow fiber membrane cassette.

The following definitions of terms apply throughout this specification and the claims.
“Membrane element” refers to a membrane (hollow fiber membrane bundle, flat membrane, etc.) fixed to a support member (housing, etc.).
“Membrane module” refers to a unit in which a plurality of membrane elements are integrated.
“Membrane cassette” refers to an integral membrane element and diffuser.
“Membrane unit” refers to a combination of a membrane module and an air diffuser.

<Hollow fiber membrane cassette>
As shown in FIGS. 1 and 2, the hollow fiber membrane cassette 10 includes a plurality of rectangular hollow fiber membrane elements 11 aligned in parallel to each other, and surrounds the four sides of the hollow fiber membrane element 11, and partially includes hollow fibers. And a frame 21 that holds the membrane element 11.

  The distance between adjacent hollow fiber membrane elements 11 is preferably 1 mm or less, particularly preferably 0 mm, at the closest point. If the interval between adjacent hollow fiber membrane elements 11 is narrow (if in contact), the hollow fiber membrane cassette 10 can be made more compact and light.

  The number of the hollow fiber membrane elements 11 per one hollow fiber membrane cassette 10 is preferably 2 to 20, and more preferably 2 to 10. If the number of hollow fiber membrane elements 11 per hollow fiber membrane cassette 10 is equal to or greater than the lower limit of the above range, the membrane area per hollow fiber membrane cassette 10 will increase, and the hollow fiber immersed in the water tank The number of membrane cassettes 10 can be reduced. If the number of hollow fiber membrane elements 11 per hollow fiber membrane cassette 10 is less than or equal to the upper limit of the above range, the hollow fiber membrane cassette 10 does not become too heavy, and the hollow fiber membrane cassette 10 is manually removed from the water tank. It's easy to do.

The length in the longitudinal direction of the hollow fiber membrane cassette 10 is preferably 1 m or less, more preferably 0.5 to 1 m, and even more preferably 0.65 to 0.85 m.
If the length in the longitudinal direction of the hollow fiber membrane cassette 10 is equal to or greater than the lower limit of the above range, the membrane area per one hollow fiber membrane cassette 10 will increase, and the number of hollow fiber membrane cassettes 10 immersed in the water tank will be reduced. Can be reduced. If the length of the hollow fiber membrane cassette 10 in the vertical direction is not more than the upper limit of the above range, the hollow fiber membrane cassette 10 does not become too heavy, and the water tank does not become too deep, and the hollow fiber membrane cassette 10 is removed from the water tank. Easy to put in and out by human power.

The length of the horizontal direction of the hollow fiber membrane cassette 10 is preferably 0.5 to 2.2 m, and more preferably 1 to 1.2 m.
If the length of the hollow fiber membrane cassette 10 in the lateral direction is equal to or greater than the lower limit of the above range, the membrane area per one hollow fiber membrane cassette 10 is increased, and the number of hollow fiber membrane cassettes 10 immersed in the water tank is determined. Can be reduced. If the length in the horizontal direction of the hollow fiber membrane cassette 10 is equal to or less than the upper limit of the above range, the hollow fiber membrane cassette 10 does not become too heavy, and the hollow fiber membrane cassette 10 can be easily taken in and out of the water tank.

The thickness of the hollow fiber membrane cassette 10 is preferably 30 to 300 mm, and more preferably 80 to 120 mm.
If the thickness of the hollow fiber membrane cassette 10 is equal to or greater than the lower limit of the above range, the membrane area per one hollow fiber membrane cassette 10 increases, and the number of hollow fiber membrane cassettes 10 immersed in the water tank can be reduced. it can. If the thickness of the hollow fiber membrane cassette 10 is less than or equal to the upper limit of the above range, the hollow fiber membrane cassette 10 does not become too heavy, and the hollow fiber membrane cassette 10 can be easily taken in and out of the water tank.

The mass of the hollow fiber membrane cassette 10 in a wet state is preferably 30 kg or less, more preferably 5 to 30 kg, and further preferably 15 to 30 kg. If the mass of the hollow fiber membrane cassette 10 in the wet state is equal to or greater than the lower limit of the above range, the membrane area per one hollow fiber membrane cassette 10 is increased, and the number of hollow fiber membrane cassettes 10 immersed in the water tank is determined. Can be reduced. If the mass of the hollow fiber membrane cassette 10 in a wet state is less than or equal to the upper limit of the above range, the hollow fiber membrane cassette 10 can be easily taken in and out of the water tank.
The mass of the hollow fiber membrane cassette 10 in a wet state is the mass of the hollow fiber membrane cassette 10 immediately after the hollow fiber membrane cassette 10 is dipped in a water tank containing water to be treated for one day or more and then pulled up.

(Hollow fiber membrane element)
As shown in FIG. 3, the hollow fiber membrane element 11 includes a sheet-like hollow fiber membrane bundle 14 in which a plurality of hollow fiber membranes 13 are aligned in one direction; and the length of the hollow fiber membrane 13 of the hollow fiber membrane bundle 14. A first housing 15 in which the first end in the length direction is inserted; and a second housing 16 in which the second end in the length direction of the hollow fiber membrane 13 of the hollow fiber membrane bundle 14 is inserted. Have.

The first end of the hollow fiber membrane bundle 14 is inserted into the first housing 15 through a slit portion formed on the side wall of the rectangular tubular first housing 15, and the opening at the end of the hollow fiber membrane 13 is opened. In a maintained state, it is fixed liquid-tightly by a potting material (not shown).
The second end of the hollow fiber membrane bundle 14 is inserted into the second housing 16 through a slit formed in the side wall of the square tubular second housing 16, and the opening at the end of the hollow fiber membrane 13 is opened. In a maintained state, it is fixed liquid-tightly by a potting material (not shown).

The first housing 15 includes a first water intake port 17 that protrudes outward from the upper end of the hollow fiber membrane 13 in the length direction; a second water intake port 18 that protrudes downward from the lower end; Have
The second housing 16 includes a first water intake port 19 formed to protrude outward in the length direction of the hollow fiber membrane 13 from the upper end; a second water intake port 20 formed to protrude downward from the lower end; Have

The first water intake port 17 of the first housing 15 is used for taking out the liquid filtered by the hollow fiber membrane 13 and collected in the water collection space in the first housing 15 to the outside of the hollow fiber membrane element 11. It is. The first water intake 17 can take out the liquid to the first upper collective block 27 by fitting into the insertion hole 34 of the first upper collective block 27 in the first vertical member 22 of the frame 21 described later. In addition, the hollow fiber membrane element 11 is fixed to the frame 21.
The second water intake port 18 of the first housing 15 is fitted into the insertion hole 36 of the first lower assembly block 28 in the first vertical member 22 of the frame 21 described later, whereby the hollow fiber membrane element 11. Is fixed to the frame 21.

The first water intake port 19 of the second housing 16 is fitted into the insertion hole 37 of the second upper assembly block 30 in the second vertical member 23 of the frame 21 described later, whereby the hollow fiber membrane element 11. Is fixed to the frame 21.
The second water intake port 20 of the second housing 16 is fitted into the insertion hole 38 of the second lower assembly block 31 in the second vertical member 23 of the frame 21 described later, whereby the hollow fiber membrane element 11. Is fixed to the frame 21.

Examples of the material of the hollow fiber membrane 13 include polysulfone resin, polyacrylonitrile, cellulose derivatives, polyolefin (polyethylene, polypropylene, etc.), fluorine resin (polyvinylidene fluoride, polytetrafluoroethylene, etc.), polyamide, polyester, polymethacrylate. , Polyacrylate, polyvinyl alcohol, copolymers of these resins, and those obtained by introducing a substituent into a part of these resins. The hollow fiber membrane 13 preferably contains one or more of these resins.
The hollow fiber membrane 13 may have a support layer in the inner layer or the outer layer. Examples of the material for the support layer include liquid-permeable materials, and hollow fiber materials (hollow knitted fabrics, hollow braids, etc.) from the viewpoint of mechanical strength and flexibility.

  The material of the first housing 15 and the second housing 16 is preferably a material having mechanical strength and durability. For example, polycarbonate, polysulfone, polyolefin, polyvinyl chloride, acrylic resin, acrylonitrile-butadiene-styrene (ABS). ) Resin, modified polyphenylene ether and the like. It is preferable that the 1st housing 15 and the 2nd housing 16 contain 1 or more types of these resin.

  Examples of the potting material include cured products of thermosetting resins (epoxy resins, unsaturated polyester resins, etc.), polyurethane resins, silicone fillers, and various hot melt resins.

The length in the length direction of the hollow fiber membrane 13 of the hollow fiber membrane element 11 is preferably 0.4 to 2 m, and more preferably 0.8 to 1.2 m.
The length of the hollow fiber membrane element 11 in the length direction of the housing is preferably 0.8 m or less, more preferably 0.4 to 0.8 m, and even more preferably 0.5 to 0.7 m.
6-50 mm is preferable and, as for the thickness (thickness of a housing) of the hollow fiber membrane element 11, 10-30 mm is more preferable.
When the size of the hollow fiber membrane element 11 is equal to or greater than the lower limit of the above range, the membrane area per one hollow fiber membrane element 11 is sufficiently widened. Therefore, since the number of the hollow fiber membrane elements 11 per one hollow fiber membrane cassette 10 does not increase too much, the hollow fiber membrane cassette 10 does not become too heavy, and the hollow fiber membrane cassette 10 can be easily taken in and out of the water tank. . If the size of the hollow fiber membrane element 11 is less than or equal to the upper limit of the above range, the hollow fiber membrane element 11 does not become too heavy and the hollow fiber membrane cassette 10 can be easily taken in and out of the water tank.

(flame)
The frame 21 includes a first vertical member 22 to which the first housing 15 of the plurality of hollow fiber membrane elements 11 is fixed; a second vertical member to which the second housing 16 of the plurality of hollow fiber membrane elements 11 is fixed. A member 23; a diffuser tube 24 substantially parallel to the hollow fiber membrane 13 connecting the lower portions of the first longitudinal member 22 and the second longitudinal member 23; and the first longitudinal member 22 and the second longitudinal member 23 The upper cross member 25 which consists of a round pipe substantially parallel to the hollow fiber membrane 13 which connects upper part of each. By fixing the housings at both ends of the hollow fiber membrane element 11 in the length direction of the hollow fiber membrane element 11 to the longitudinal members of the frame 21, the hollow fiber membrane 13 has a lengthwise direction substantially parallel to the hollow fiber. The membrane element 11 is fixed.

(Vertical member)
The first longitudinal member 22 is located at the upper portion of the groove on the opposite side of the longitudinal member body 26 from the hollow fiber membrane element 11; A first upper assembly block 27 fixed to the vertical member body 26 with bolts; a first upper block 27 positioned below the groove on the hollow fiber membrane element 11 side of the vertical member body 26 and fixed to the vertical member body 26 with bolts And a lower assembly block 28.

  The second longitudinal member 23 is located at the upper part of the groove on the opposite side of the longitudinal member main body 29 from the hollow fiber membrane element 11; A second upper assembly block 30 fixed to the vertical member main body 29 with bolts; a second upper assembly block 30 positioned below the groove on the hollow fiber membrane element 11 side of the vertical member main body 29 and fixed to the vertical member main body 29 with bolts And a lower assembly block 31.

The first upper collecting block 27 in the first vertical member 22 is also a water collecting block for collecting liquid from the plurality of hollow fiber elements 11, and includes a block main body 32 and a water discharge nozzle 33 protruding upward from the block main body 32. And have. The block main body 32 has a plurality of insertion holes 34 opened to the hollow fiber membrane element 11 side through through holes (not shown) formed in the vertical member main body 26; A water collecting flow path 35 connected to the nozzle 33 is formed.
A plurality of insertion holes 36 opened upward are formed in the first lower assembly block 28 of the first vertical member 22.

The second upper assembly block 30 in the second longitudinal member 23 has a plurality of insertion holes 37 opened to the hollow fiber membrane element 11 side through through holes (not shown) formed in the longitudinal member main body 29. Is formed.
A plurality of insertion holes 38 opened upward are formed in the second lower assembly block 31 of the second vertical member 23.

The first upper assembly block 27 in the first longitudinal member 22 is inserted into the insertion hole 34 through the through hole (not shown) formed in the longitudinal member body 26, and the first housing 15 of the hollow fiber membrane element 11. After fitting the first water intake port 17, it is fixed to the longitudinal member body 26 with a bolt, so that the liquid can be taken out from the hollow fiber membrane element 11 to the first upper assembly block 27, and the first The hollow fiber membrane element 11 can be held by the vertical member 22. Further, the first upper collecting block 27 can take out the liquid from the collecting flow path 35 through the collecting hose to the collecting header (not shown) by connecting the collecting hose (not shown) to the water discharge nozzle 33. It is what you want to do.
The first lower assembly block 28 in the first vertical member 22 is fitted with the second water intake 18 of the first housing 15 of the hollow fiber membrane element 11 in the insertion hole 36, and then the vertical member main body with bolts. By being fixed to 26, the hollow fiber membrane element 11 can be held by the first longitudinal member 22.

The second upper assembly block 30 in the second vertical member 23 is inserted into the insertion hole 37 through the through hole (not shown) formed in the vertical member main body 29 and the second housing 16 of the hollow fiber membrane element 11. After the first water intake port 19 is fitted, the hollow fiber membrane element 11 can be held by the second vertical member 23 by being fixed to the vertical member body 29 with a bolt.
The second lower assembly block 31 in the second vertical member 23 is fitted with the second water intake port 20 of the second housing 16 of the hollow fiber membrane element 11 in the insertion hole 38, and then the main body of the vertical member with a bolt. By being fixed to 29, the hollow fiber membrane element 11 can be held by the second longitudinal member 23.

Examples of the material of the vertical member main body 26 and the vertical member main body 29 include metals (stainless steel, titanium, etc.) and resins (polyvinyl chloride, fluororesin, polyolefin, ABS resin, polycarbonate, etc.).
Examples of the material of the block main body 32 of the first upper assembly block 27 and other assembly blocks include polycarbonate, polysulfone, polyolefin, polyvinyl chloride, acrylic resin, ABS resin, and modified polyphenylene ether.

(Air diffuser)
The air diffuser 24 has a pipe shape in which the first end side penetrates the vertical member main body 26 of the first vertical member 22 and the second end side penetrates the vertical member main body 29 of the second vertical member 23. A cap 40 for sealing the first end of the diffuser tube main body 39; and an air supply nozzle 41 provided at the second end of the diffuser tube main body 39 bent upward. .
The air supply nozzle 41 connects an air supply hose (not shown) so that air can be supplied from the blower (not shown) to the air diffuser 24.

A plurality of diffuser holes 42 are formed in the diffuser tube main body 39.
For example, all of the air diffuser holes 42 may be opened directly below; those that are inclined 45 degrees forward along the circumferential direction from directly below, and 45 degrees rearward along the circumferential direction from directly below. What was inclined and opened may be formed alternately.

  1-8 mm is preferable and, as for the opening diameter of the diffuser hole 42, 2-6 mm is more preferable. If the opening diameter of the air diffuser hole 42 is equal to or larger than the lower limit of the above range, the air diffuser hole 42 is difficult to block. Further, the air diffusion holes 42 are easily formed. If the opening diameter of the air diffuser hole 42 is equal to or smaller than the upper limit of the above range, the air from the air diffuser tube 24 can be uniformly diffused.

  10-300 mm is preferable and, as for the pitch (distance between centers) of the diffuser hole 42, 40-150 mm is more preferable. If the pitch of the air holes 42 is equal to or greater than the lower limit of the above range, the number of air holes 42 does not increase too much and air can be uniformly diffused. If the pitch of the air diffusion holes 42 is equal to or less than the upper limit of the above range, the number of places where the air is not easily hit in the sheet-like hollow fiber membrane bundle 14 is reduced, and the cleaning efficiency of the hollow fiber membrane 13 is improved.

  Examples of the material of the air diffuser main body 39 include metals (stainless steel, titanium, etc.) and resins (polyvinyl chloride, fluororesin, polyolefin, ABS resin, polycarbonate, etc.).

(Upper horizontal member)
The upper transverse member 25 is a member that becomes a handle when the hollow fiber membrane cassette 10 is manually inserted into and removed from the water tank.
The upper horizontal member 25 has a first end fixed to the first vertical member 22 and a second end fixed to the second vertical member 23 by welding, adhesion, fitting, or the like.
Examples of the material of the upper lateral member 25 include metals (stainless steel, titanium, etc.) and resins (polyvinyl chloride, fluorine-based resins, polyolefins, ABS resins, polycarbonates, etc.). From the point of high mechanical strength, Metal is preferred.

(Installation of hollow fiber membrane cassette)
Hereinafter, installation of the hollow fiber membrane cassette 10 in the water tank will be described.
The hollow fiber membrane cassette 10 in which an air supply hose (not shown) is connected to the air supply nozzle 41 of the air diffuser 24 is inserted into the water tank and placed in the water tank. At this time, the operator may grasp the upper horizontal member 25 of the frame 21 to be a handle and manually insert the hollow fiber membrane cassette 10 into the water tank.

  After all the hollow fiber membrane cassettes 10 are inserted and arranged in the water tank, the water discharge nozzle 33 of the first vertical member 22 of the frame 21 of the hollow fiber membrane cassette 10 and the water collection by a water collection hose (not shown). A header (not shown) is connected.

  The hollow fiber membrane cassette 10 in the water tank is disposed in the water tank so that the length direction of the hollow fiber membrane 13 in the hollow fiber membrane element 11 is substantially horizontal. If the length direction of the hollow fiber membrane 13 is substantially horizontal, the hollow fiber membrane cassette 10 does not become too long in the vertical direction, so the water tank does not become too deep. Therefore, the hollow fiber membrane cassette 10 is easily taken in and out of the water tank.

The hollow fiber membrane cassette 10 in the water tank is disposed in the water tank so that the surface of the hollow fiber membrane element 11 is along the vertical direction. If the surface of the hollow fiber membrane element 11 is along the vertical direction, the air from the air diffusing tube 24 can be sufficiently supplied between the adjacent hollow fiber membrane elements 11 in the hollow fiber membrane cassette 10, and the cleaning efficiency of the hollow fiber membrane 13 is improved. Will improve.
A casing or the like into which the hollow fiber membrane cassette 10 can be inserted may be installed in the water tank, and the hollow fiber membrane cassette 10 may be accommodated in the casing or the like.

(Water treatment method)
The hollow fiber membrane 13 of the hollow fiber membrane element 11 is stored by operating the suction pump (not shown) connected to the water collection header (not shown) while storing the treated water in the water tank and supplying the treated water. The liquid collected in the water collecting space in the first housing 15 is taken out from the hollow fiber membrane element 11 to the first upper collecting block 27 in the first vertical member 22 of the frame 21, and the water discharge nozzle A water collecting hose (not shown) connected to 33 is taken out from the water collecting flow path 35 in the first upper collecting block 27 to the water collecting header.

  Simultaneously with the filtration or temporarily interrupting the filtration and operating the blower (not shown) connected to the air supply nozzle 41 of the air diffusion pipe 24 via the air supply hose (not shown), the air diffuser 24 from the blower To supply air. The air supplied to the diffuser tube 24 is diffused from the diffuser holes 42 of the diffuser tube main body 39, rises toward the hollow fiber membrane element 11, and cleans the surface of the hollow fiber membrane 13.

(maintenance)
When regular maintenance is performed, or when temporary maintenance occurs due to membrane blockage or membrane breakage, diffuser tube blockage, etc., the suction pump (not shown) and blower (not shown) are stopped, and the hollow fiber membrane cassette to be pulled up A water collection hose (not shown) is removed from the ten water discharge nozzles 33.

  The hollow fiber membrane cassette 10 to be lifted is lifted from the water tank, and the air supply hose (not shown) is removed from the air supply nozzle 41 of the air diffuser 24 to perform maintenance. At this time, the operator may hold the upper horizontal member 25 to be a handle and pull the hollow fiber membrane cassette 10 out of the water tank by human power.

(Mechanism of action)
The hollow fiber membrane cassette 10 described above can be made compact and lightweight for the following reasons (i) to (iv), and can be easily pulled up from the water tank. As a result, the maintenance of the hollow fiber membrane element 11 and the air diffuser 24 can be easily performed.
(I) By fixing the housings at both ends in the length direction of the hollow fiber membrane 13 of the hollow fiber membrane element 11 to the vertical members of the frame 21, the length direction of the hollow fiber membrane 13 is substantially horizontal. The hollow fiber membrane element 11 is fixed to the base. Therefore, the length of the hollow fiber membrane cassette 10 in the vertical direction can be shortened, and there is no need to deepen the water tank. Therefore, the hollow fiber membrane cassette 10 can be easily pulled up from the water tank.
(Ii) Since the hollow fiber membrane element 11 is fixed so that the length direction of the hollow fiber membrane 13 is substantially horizontal, the rise of air diffused from the air diffuser tube 24 is not hindered by the housing. Therefore, since the space | interval of the adjacent hollow fiber membrane element 11 can be narrowed, the hollow fiber membrane cassette 10 can be made compact and lightweight, and it can carry it by human power. Therefore, the hollow fiber membrane cassette 10 can be easily pulled up from the water tank.
(Iii) Of the members constituting the frame 21 of the hollow fiber membrane cassette 10, a member parallel to the hollow fiber membrane 13 on the lower side of the hollow fiber membrane element 11 also serves as the aeration tube 24, and the upper side of the hollow fiber membrane element 11. Since the member parallel to the hollow fiber membrane 13 is the upper lateral member 25 which also serves as a handle, the number of members constituting the hollow fiber membrane cassette 10 can be reduced. Therefore, the hollow fiber membrane cassette 10 can be made compact and lightweight, and can be carried by human power. Therefore, the hollow fiber membrane cassette 10 can be easily pulled up from the water tank.
(Iv) Since the membrane element is the hollow fiber membrane element 11, a membrane area per unit volume can be increased as compared with a flat membrane element. Therefore, the hollow fiber membrane cassette 10 can be made compact and lightweight, and can be carried by human power. Therefore, the hollow fiber membrane cassette 10 can be easily pulled up from the water tank.

(Other embodiments)
The hollow fiber membrane cassette of the present invention is a hollow fiber membrane cassette comprising a plurality of hollow fiber membrane elements and a frame for holding the hollow fiber membrane elements; the hollow fiber membrane element has a plurality of hollow fiber membranes in one direction. The aligned hollow fiber membrane bundle, the first housing in which the first end of the hollow fiber membrane bundle in the length direction of the hollow fiber membrane is fixed, and the length direction of the hollow fiber membrane of the hollow fiber membrane bundle A second housing having a second end fixed thereto; a frame having a first longitudinal member to which the first housing of the hollow fiber membrane element is fixed; and a second of the hollow fiber membrane element. The second vertical member to which the housing is fixed, the air diffuser pipe connecting the lower portions of the first vertical member and the second vertical member, and the upper portions of the first vertical member and the second vertical member are connected to each other. What is necessary is just to have an upper cross member, and the hollow fiber membrane cassette 1 in the illustrated example But it is not limited to.

For example, the hollow fiber membrane element is not limited to a rectangular hollow fiber membrane element, but is a cylindrical hollow fiber membrane element including a cylindrical hollow fiber membrane bundle in which a plurality of hollow fiber membranes are aligned in one direction. There may be. A rectangular hollow fiber membrane element is preferable from the viewpoint of high cleaning efficiency of the hollow fiber membrane by air diffused from the diffuser.
The number of hollow fiber membrane elements in the hollow fiber membrane cassette is not limited to 5 in the illustrated example, and may be 2 to 4 or 6 or more.
There may be a plurality of diffuser tubes in the hollow fiber membrane cassette. From the viewpoint of weight reduction of the hollow fiber membrane cassette, one is preferable.
There may be a plurality of upper transverse members that are handles in the hollow fiber membrane cassette. From the viewpoint of weight reduction of the hollow fiber membrane cassette, one is preferable.

In the hollow fiber membrane cassette, the longitudinal member body 26 of the first longitudinal member 22 and the longitudinal member body 29 of the second longitudinal member 23 in the frame 21 are U-shaped members as shown in FIG. As shown in FIG. 5, it may be a simple plate-like member. Further, the vertical member main body 26 and the vertical member main body 29 may be round bars, square bars, round pipes, square pipes, angles (L-shaped), or the like.
The fixing means of the hollow fiber membrane element in the hollow fiber membrane cassette is not limited to the assembly block in the illustrated example. The assembly block is preferable from the viewpoint that the fixing means can have a simple structure, and as a result, the hollow fiber membrane cassette can be made compact and lightweight.
In the illustrated hollow fiber membrane cassette 10, the second upper assembly block 30 does not have a water collection function, but, like the first upper assembly block 27, is a water collection block having a water collection function. Also good. By using the first upper assembly block 27 and the second upper assembly block 30 as water collection blocks, the mass of the hollow fiber membrane cassette 10 slightly increases, but the effect of suppressing energy required for membrane filtration is high.
The upper lateral member in the frame may be of a shape that can support the weight of the wet hollow fiber membrane cassette and can be grasped by hand. The upper horizontal member is not limited to the illustrated round pipe, and may be a flat plate, round bar, square bar, square pipe, angle (L-shaped), channel (U-shaped), H-shaped, or the like.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

Example 1
A hollow fiber membrane element 11 shown in FIG. 3 was produced. As for the size of the hollow fiber membrane element 11, the length in the length direction of the hollow fiber membrane 13 was about 1000 mm, the length in the length direction of the housing was about 600 mm, and the thickness was 18 mm at the maximum. The total membrane area on the surface of the hollow fiber membrane 13 was 5 m ² .

A rectangular shape in which the hollow fiber membrane element 11 is fixed to the frame 21 so that the length direction of the hollow fiber membrane 13 is substantially horizontal as shown in FIGS. The hollow fiber membrane cassette 10 was produced.
As the diffuser tube body 39, a 20A stainless steel pipe formed with a plurality of diffuser holes 42 was used.
As the upper transverse member 25, a flat plate made of stainless steel was used.
As the vertical member main body 26 and the vertical member main body 29, members having an H-shaped cross section made of stainless steel were used.
As the assembly block, an ABS resin block in which insertion holes were formed was used. A water collection channel 35 was further formed in the block body 32 of the first upper assembly block 27, and a water discharge nozzle 33 was attached.

  The interval between adjacent hollow fiber membrane elements 11 in the hollow fiber membrane cassette 10 was 0 mm at the closest point. The size of the hollow fiber membrane cassette 10 was 1128 mm in the lateral direction, 785 mm in the longitudinal direction, and 100 mm in thickness. The dry mass of the hollow fiber membrane cassette 10 was 17 kg.

Four hollow fiber membrane cassettes 10 in which the air supply hose 6 was connected to the air supply nozzle 41 of the air diffuser 24 were inserted into a stainless steel water tank and arranged.
The water discharge nozzle 33 of the first vertical member 22 of the frame 21 and the water collection header (not shown) were connected by a water collection hose (not shown).

Water to be treated containing 15 mg / L of kaolin as a turbid component was prepared. The water to be treated containing turbidity was put in the water tank.
A suction pump (not shown) was operated to perform a membrane filtration operation to obtain filtered water. The filtration flow rate was 140 L / min. At the same time, water to be treated containing turbidity at the same flow rate as the filtration flow rate was supplied from a water supply hose (not shown) into the water tank. The membrane filtration operation was performed for 30 minutes.
The suction pump (not shown) was stopped and the supply of water to be treated was stopped at the same time. The blower was operated for 60 seconds to perform aeration operation. The air volume of air supplied from the blower was 55 m ³ / hour.
The above membrane filtration operation and aeration operation were made into 1 cycle, and the operation was repeated until it became a total of 10 cycles.

  The concentrated water in the water tank was drained. An operation step was placed beside the water tank, and one of the hollow fiber membrane cassettes 10 was taken out standing on it. At this time, the hollow fiber membrane cassette 10 could be pulled up manually without using lifting equipment such as a hoist crane. The mass of the hollow fiber membrane cassette 10 in a wet state was 24.5 kg.

(Comparative Example 1)
As the hollow fiber membrane element 11, the same one as in Example 1 was prepared.
Using the five hollow fiber membrane elements 11, a rectangular hollow fiber membrane cassette in which the hollow fiber membrane elements 11 were fixed to the frame so that the length direction of the hollow fiber membrane 13 was substantially vertical was produced.

The size of the hollow fiber membrane cassette was 785 mm in the horizontal direction and 1228 mm in the vertical direction.
When the hollow fiber membrane element 11 is fixed to the frame so that the length direction of the hollow fiber membrane 13 is substantially vertical, the housing hinders the rise of air diffused from the air diffusion tube 24. In order to effectively clean the hollow fiber membrane 13 with the diffused air, the interval between the adjacent hollow fiber membrane elements 11 in the hollow fiber membrane cassette was set to 3 mm at the closest point. Therefore, the thickness of the hollow fiber membrane cassette was 120 mm, and the dry mass of the hollow fiber membrane cassette was 23 kg.

A hollow fiber membrane cassette was installed in the water tank in the same manner as in Example 1. The membrane filtration operation and the aeration operation were repeated under the same conditions as in Example 1.
The concentrated water in the water tank was drained. A working step was placed beside the water tank and one of the hollow fiber membrane cassettes was taken out standing on it. Since the hollow fiber membrane cassette is vertically long and heavy, the hollow fiber membrane cassette cannot be pulled up manually, and a hoist crane has to be used. The wet mass of the hollow fiber membrane cassette was 30.5 kg.

(Comparative Example 2)
The length direction of the hollow fiber membrane 13 is substantially vertical as in Comparative Example 1, except that the distance between adjacent hollow fiber membrane elements 11 in the hollow fiber membrane cassette is 0 mm at the closest point. A rectangular hollow fiber membrane cassette in which the hollow fiber membrane element 11 was fixed to a frame was produced.

  The distance between adjacent hollow fiber membrane elements 11 in the hollow fiber membrane cassette was 0 mm at the closest point. The hollow fiber membrane cassette 10 had a lateral length of 785 mm, a longitudinal length of 1075 mm, and a thickness of 100 mm. The dry mass of the hollow fiber membrane cassette 10 was 22 kg.

  A hollow fiber membrane cassette was installed in the water tank in the same manner as in Example 1. The membrane filtration operation and the aeration operation were repeated under the same conditions as in Example 1. Since the housings of the adjacent hollow fiber membrane elements 11 are in contact with each other, the rise of the air diffused from the diffuser tube 24 is hindered by the housing, and the hollow fiber membrane 13 is not washed with the diffused air. It was. Therefore, the transmembrane pressure difference increased early.

  The concentrated water in the water tank was drained. A working step was placed beside the water tank and one of the hollow fiber membrane cassettes was taken out standing on it. Since the hollow fiber membrane cassette is vertically long, the hollow fiber membrane cassette cannot be pulled up manually, and a hoist crane has to be used. The mass of the hollow fiber membrane cassette in a wet state was 30 kg.

  The hollow fiber membrane cassette of the present invention is useful for various wastewater treatment (industrial wastewater, domestic wastewater, etc.), groundwater and river water treatment, seawater desalination treatment, and the like.

  DESCRIPTION OF SYMBOLS 10 Hollow fiber membrane cassette, 11 Hollow fiber membrane element, 13 Hollow fiber membrane, 14 Hollow fiber membrane bundle, 15 1st housing, 16 2nd housing, 17 1st water intake port, 18 2nd water intake port, 19 1st water intake, 20 2nd water intake, 21 frame, 22 1st vertical member, 23 2nd vertical member, 24 diffuser pipe, 25 upper horizontal member, 26 vertical member main body, 27 1st upper assembly Block, 28 first lower collecting block, 29 vertical member main body, 30 second upper collecting block, 31 second lower collecting block, 32 block main body, 33 water discharge nozzle, 34 insertion hole, 35 water collecting flow path, 36 Insertion hole, 37 Insertion hole, 38 Insertion hole, 39 Air diffuser body, 40 Cap, 41 Air supply nozzle, 42 Air diffusion hole.

Claims (5)

A hollow fiber membrane cassette comprising a plurality of hollow fiber membrane elements and a frame for holding the hollow fiber membrane elements,
The hollow fiber membrane element includes a hollow fiber membrane bundle in which a plurality of hollow fiber membranes are aligned in one direction, and a first end portion of the hollow fiber membrane bundle in the length direction of the hollow fiber membrane is fixed. A first housing and a second housing to which a second end of the hollow fiber membrane bundle in the length direction of the hollow fiber membrane is fixed;
The frame includes a first vertical member to which the first housing of the hollow fiber membrane element is fixed, a second vertical member to which the second housing of the hollow fiber membrane element is fixed, and the first A hollow fiber membrane having a diffuser pipe connecting the lower parts of one vertical member and the second vertical member and an upper horizontal member connecting upper parts of the first vertical member and the second vertical member cassette. The hollow fiber membrane element is a rectangular hollow fiber membrane element having a sheet-like hollow fiber membrane bundle, and a tubular first housing and a second housing extending in the vertical direction,
The first vertical member includes a first upper assembly block to which upper ends of the first housings of the plurality of hollow fiber membrane elements are fixed, and the first housing of the plurality of hollow fiber membrane elements. A first lower assembly block having a lower end fixed thereto;
The second vertical member includes a second upper assembly block to which upper ends of the second housings of the plurality of hollow fiber membrane elements are fixed, and the second housing of the plurality of hollow fiber membrane elements. The hollow fiber membrane cassette according to claim 1, further comprising a second lower assembly block to which a lower end portion is fixed.   The hollow fiber membrane cassette according to claim 1 or 2, wherein an interval between the adjacent hollow fiber membrane elements is 1 mm or less at a closest position.   The hollow fiber membrane cassette according to any one of claims 1 to 3, wherein a length in a longitudinal direction is 1 m or less.   The hollow fiber membrane cassette according to any one of claims 1 to 4, wherein a mass in a wet state is 30 kg or less.

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