Hollow fiber membrane element, hollow fiber membrane module, water treatment device, and water treatment method

Abstract

The present application provides a hollow fiber membrane element having excellent pressure resistance, a hollow fiber membrane module, a water treatment device, and a water treatment method. The hollow fiber membrane element has a hollow fiber membrane, a water collecting pipe, and a water outlet for taking out treated water from the water collecting pipe, the hollow fiber membrane and the water collecting pipe are fixed by a pouring portion, the water collecting pipe has a water collecting path inside the water collecting pipe using the pouring portion and the water collecting pipe as wall surfaces, an end portion of the hollow fiber membrane communicates with the water collecting pipe, and a cross-sectional area of any water collecting path cross section of the water collecting pipe perpendicular to a long side direction is 100 to 350 mm 2 .

Description

Technical Field

[0001] This invention relates to a hollow fiber membrane element, a hollow fiber membrane assembly, a water treatment device, and a water treatment method. Background Technology

[0002] Hollow fiber membrane elements are widely used in the production of sterile water, beverage water, and highly pure water. One known hollow fiber membrane element (Patent Document 1) has water collection pipes at both ends along its length and tubular support columns that are connected to the water collection pipes.

[0003] In a hollow fiber membrane element like that described in Patent Document 1, tubular protrusions communicating with a water collection section are provided at both ends of the water collection pipe. These protrusions are used to embed into the ends of a tubular support column. In the manufacture of this hollow fiber membrane element, for example, resin is injected around the protrusions with the water collection pipe facing upwards. The end of the tubular support column is then inserted into the end of the water collection pipe such that the protrusions are inserted into the end of the tubular support column, and then the resin is allowed to harden. By inserting the tubular support column into the end of the water collection pipe with resin injected around the protrusions, the gap between the protrusion inserted into the end of the tubular support column and the tubular support column is also filled with resin. Therefore, a hollow fiber membrane element with excellent water tightness at the connection between the water collection pipe and the tubular support column can be obtained.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Chinese Utility Model No. 202006088 Specification

[0007] Hollow fiber membrane elements with low pressure loss are preferred in terms of requiring less energy during operation.

[0008] Therefore, in hollow fiber membrane elements where water is collected from the end of the hollow fiber membrane via a water collection pipe, hollow fiber membrane elements with a large cross-sectional area of ​​the water passage inside the water collection pipe have low pressure loss and are therefore preferred.

[0009] Hollow fiber membrane elements are typically used in a hollow fiber membrane module, often employing multiple elements. Thinner hollow fiber membrane elements tend to improve membrane cleanability and increase the throughput per unit volume. Therefore, thinner hollow fiber membrane elements may be used when location constraints exist.

[0010] When using thin hollow fiber membrane elements, in order not to increase pressure loss, the cross-sectional area of ​​the water passage inside the water collection pipe is increased by extending the maximum length (height) between the bottom of the water collection pipe and the portion of the casting part that is furthest from the bottom of the water collection pipe in contact with the wall of the water collection pipe.

[0011] As a cleaning method for hollow fiber membrane elements, there are known methods, such as reverse cleaning, in which cleaning water flows from the water collection pipe side to the hollow fiber membrane in order to remove dirt.

[0012] When the height of the water channel inside the water collection pipe of the thinner hollow fiber membrane element is increased, it is found that leakage can occur due to damage when studying reverse cleaning under high pressure (e.g., above 1 MPa), so there is still room for improvement in pressure resistance. Summary of the Invention

[0013] The present invention aims to provide a hollow fiber membrane element and a hollow fiber membrane assembly with excellent pressure resistance.

[0014] Technical means for solving problems

[0015] The present invention has the following structure.

[0016] [1] A hollow fiber membrane element comprising: a hollow fiber membrane, a water collection pipe, and an outlet for extracting treated water from the water collection pipe.

[0017] The hollow fiber membrane is fixed to the water collection pipe via a casting section.

[0018] The water collection pipe has a water collection channel inside, with the pouring section and the water collection pipe serving as walls.

[0019] The end of the hollow fiber membrane is connected to the water collection pipe.

[0020] The cross-sectional area of ​​any water collection path perpendicular to the long side of the water collection pipe is 100–350 mm². 2 .

[0021] [2] In the hollow fiber membrane element described in [1], the length of the long side of the hollow fiber membrane in the water collection channel section is 20 mm or less.

[0022] [3] In the hollow fiber membrane element described in [1] or [2], at least one of a deformation suppression member that is in contact with the wall of the water collection pipe and a deformation suppression member that is integrated with the water collection pipe is provided.

[0023] [4] In the hollow fiber membrane element described in [3], the deformation suppression component is a rib.

[0024] [5] In any of the hollow fiber membrane elements described in [1] to [4], the water collection pipe has a step and the step is engaged with the lower part of the casting portion.

[0025] [6] In the hollow fiber membrane element described in [5], the step is 0.5 mm or more.

[0026] [7] Among the hollow fiber membrane elements described in any of [1] to [6],

[0027] The water collection pipe consists of a first water collection pipe and a second water collection pipe.

[0028] The second water collection pipe is located on the opposite side of the long side of the hollow fiber membrane of the first water collection pipe, and the first water collection pipe and the second water collection pipe are connected by a support.

[0029] [8] In the hollow fiber membrane element described in [7], the water passage inside the support is connected to the first water passage of the first water collection pipe and the second water passage of the second water collection pipe.

[0030] [9] In the hollow fiber membrane element described in [8], when the cross-sectional area of ​​any face of the water collection path of the water collection pipe perpendicular to the long side direction is set as b, and the cross-sectional area of ​​any face of the water passage of the support column perpendicular to the long side direction is set as a, the relationship 0.5×a≤b is satisfied.

[0031]

[10] In the hollow fiber membrane element described in [9], the following formulas (1) and (2) are satisfied:

[0032] a / b1≥0.9···(1)

[0033] a / b²≥0.9···(2)

[0034] Where 'a' is any cross-sectional area of ​​the water passage of the support pillar.

[0035] b1 is the cross-sectional area of ​​any face perpendicular to the long side of the first water collection channel of the first water collection pipe.

[0036] b2 is the cross-sectional area of ​​any surface of the second water collection channel of the second water collection pipe that is perpendicular to the direction of the long side.

[0037]

[11] In the hollow fiber membrane elements described in [9] or

[10] , the following formulas (3) and (4) are satisfied:

[0038] 0.5×a≤b1···(3)

[0039] 0.5×a≤b2···(4)

[0040] Where 'a' is any cross-sectional area of ​​the water passage of the support pillar.

[0041] b1 is the cross-sectional area of ​​any face perpendicular to the long side of the first water collection channel of the first water collection pipe.

[0042] b2 is the cross-sectional area of ​​any surface of the second water collection channel of the second water collection pipe that is perpendicular to the direction of the long side.

[0043]

[12] A hollow fiber membrane module comprising a plurality of hollow fiber membrane elements described in any one of [1] to

[11] .

[0044]

[13] A water treatment apparatus comprising a hollow fiber membrane module as described in

[12] and an air dissipation device disposed below the hollow fiber membrane module.

[0045]

[14] A water treatment method using the water treatment apparatus described in

[13] .

[0046] The present invention may also have the following other structures.

[0047] [A1] A hollow fiber membrane element having:

[0048] Hollow fiber membrane;

[0049] A water collection pipe is used to collect the treated water recovered by the hollow fiber membrane; and

[0050] The outlet is used to extract treated water from the collection pipe, wherein...

[0051] The hollow fiber membrane is fixed to the water collection pipe via a casting section.

[0052] The water collection pipe has a water collection channel inside, with the pouring section and the water collection pipe serving as walls.

[0053] The water collection pipe has supports extending parallel to the hollow fiber membrane.

[0054] The support column has an internal water passage that communicates with the water collection channel.

[0055] The cross-sectional area of ​​the water collection path on the plane perpendicular to the long side of the water collection pipe is less than the cross-sectional area of ​​the water passage.

[0056] [A2] In the hollow fiber membrane element described in [A1], when the cross-sectional area of ​​the water collection channel is set as b and the cross-sectional area of ​​the water passage is set as a, the following relationship is satisfied.

[0057] 0.5×a≤b.

[0058] [A3] In the hollow fiber membrane element described in [A1] or [A2], the maximum length between the walls of the water collection pipe that are spaced apart in the short side direction of the water collection pipe is defined as W.

[0059] When H is defined as the maximum length of the hollow fiber membrane in the direction perpendicular to the long side of the water collection pipe, extending from the portion furthest from the bottom surface of the casting section in contact with the wall to the bottom surface, the following relationship is satisfied:

[0060] H≤1.2×W.

[0061] [A4] In any of the hollow fiber membrane elements described in [A1] to [A3], the water collection pipe comprises: a first water collection pipe disposed on one side of the hollow fiber membrane in the long side direction and having a first water collection path; and a second water collection pipe disposed on the other side of the hollow fiber membrane in the long side direction and having a second water collection path.

[0062] The first water collection pipe and the second water collection pipe are connected by the support pillar, and the first water collection path and the second water collection path are connected to the water passage.

[0063] [A5] In any of the hollow fiber membrane elements described in [A1] to [A4], ribs are provided at the lower part of the water collection pipe.

[0064] [A6] In the hollow fiber membrane element described in [A5], the ribs are configured to extend for more than 70% of the length of the long side of the water collection path.

[0065] [A7] A hollow fiber membrane element having:

[0066] Hollow fiber membrane;

[0067] A water collection pipe is used to collect the treated water recovered by the hollow fiber membrane; and

[0068] The outlet is used to extract treated water from the collection pipe, wherein...

[0069] The hollow fiber membrane is fixed to the water collection pipe via a casting section.

[0070] The water collection pipe has a water collection channel inside, with the pouring section and the water collection pipe serving as walls.

[0071] The end of the hollow fiber membrane is connected to the water collection pipe, and

[0072] The cross-sectional area of ​​the water collection path on the plane perpendicular to the long side of the water collection pipe is 100-350 mm². 2 ,

[0073] The length of the water collection path in the long side direction of the hollow fiber membrane on the surface of the water collection pipe perpendicular to the long side direction is less than 20 mm.

[0074] [A8] A hollow fiber membrane element, comprising:

[0075] Hollow fiber membrane;

[0076] A water collection pipe is used to collect the treated water recovered by the hollow fiber membrane; and

[0077] The outlet is used to extract treated water from the collection pipe, wherein...

[0078] The hollow fiber membrane is fixed to the water collection pipe via a casting section.

[0079] The water collection pipe has a water collection channel inside, with the pouring section and the water collection pipe serving as walls.

[0080] The end of the hollow fiber membrane is connected to the water collection pipe, and

[0081] The cross-sectional area of ​​the water collection passage perpendicular to the long side of the water collection pipe is 100-350 mm². 2 ,

[0082] The hollow fiber membrane element has a component that is in contact with and / or integrated with the wall of the water collection pipe to inhibit deformation of the wall.

[0083] [A9] In the hollow fiber membrane element described in [A7] or [A8], the water collection pipe has a first water collection pipe and a second water collection pipe.

[0084] The second water collection pipe is located on the opposite side of the long side of the hollow fiber membrane of the first water collection pipe, and the first water collection pipe and the second water collection pipe are connected by a support.

[0085] [A10] In the hollow fiber membrane element described in [A9], the water collection section located inside the support and the first water collection pipe is connected to the second water collection section located inside the second water collection pipe.

[0086] [A11] In the hollow fiber membrane element described in [A10], the ratio a / b1 of the cross-sectional area a of the water supply portion of the support column to the cross-sectional area b1 of the water supply portion of the first water collection pipe and the ratio a / b2 of the cross-sectional area a of the water supply portion of the support column to the cross-sectional area b2 of the water supply portion of the second water collection pipe simultaneously satisfy formulas (1) and (2):

[0087] a / b1≥0.9···(1)

[0088] a / b2≥0.9···(2).

[0089] [A12] In any of the hollow fiber membrane elements described in [A1] to [A11], the surface roughness of the interface between the water collection pipe and the casting part is Ra6.3 to 25.

[0090] [A13] In any of the hollow fiber membrane elements described in [A1] to [A12], the interface between the water collection pipe and the casting portion has irregularities.

[0091] [A14] In any of the hollow fiber membrane elements described in [A1] to [A13], a step is provided at the lower part of the interface between the water collection pipe and the casting part.

[0092] [A15] In the hollow fiber membrane element described in [A14], the step is 0.5 mm or more.

[0093] [A16] A hollow fiber membrane module comprising a plurality of hollow fiber membrane elements as described in any one of [A1] to [A15].

[0094] The effects of the invention

[0095] According to the present invention, hollow fiber membrane elements and hollow fiber membrane assemblies with excellent pressure resistance can be provided. Attached Figure Description

[0096] Figure 1 This is a perspective view showing an example of the hollow fiber membrane element of the present invention.

[0097] Figure 2 yes Figure 1 Front view of a hollow fiber membrane element.

[0098] Figure 3 yes Figure 2 A cross-sectional view of a hollow fiber membrane element (AA).

[0099] Figure 3A This is a modified example of the hollow fiber membrane element of the present invention.

[0100] Figure 3B This is a modified example of the hollow fiber membrane element of the present invention.

[0101] Figure 3C This is a modified example of the hollow fiber membrane element of the present invention.

[0102] Figure 3D This is a modified example of the hollow fiber membrane element of the present invention.

[0103] Figure 3E This is a modified example of the hollow fiber membrane element of the present invention.

[0104] Figure 3F This is a modified example of the hollow fiber membrane element of the present invention.

[0105] Figure 3G This is a modified example of the hollow fiber membrane element of the present invention.

[0106] Figure 3H This is a modified example of the hollow fiber membrane element of the present invention.

[0107] Figure 4 yes Figure 1 BB cross-sectional view of a hollow fiber membrane element.

[0108] Figure 5 yes Figure 4 CC cross-sectional view of a hollow fiber membrane element.

[0109] Figure 6 This is a modified example of the hollow fiber membrane element of the present invention.

[0110] Symbol Explanation

[0111] 1…Hollow fiber membrane element, 10…Hollow fiber membrane sheet, …10a First opening end, 10b…Second opening end, 11…Hollow fiber membrane, 12…First water collection pipe (water collection pipe), 13a…First end, 13b…Second end, 14…Second water collection pipe (water collection pipe), 15a…First end, 15b…Second end, 16…First tubular support (support), 17a…First end, 17b…Second end, 18…Second tubular support (support), 19a…First end, 19b…Second end, 20a…Sidewall portion, 20b…Sidewall portion, 20c…Bottom, 20d…Opening Mouth, 20e… First water collection channel (water collection channel), 20f… Second water collection channel (water collection channel), 20g… Step, 21… Component, 21a… Deformation suppression component, 22a… Casting part, 23… Casting shell, 23a… Casting part, 23b… Casting part, 23c… Interface, 24a… Cylindrical part, 24b… Protrusion, 24c… Peripheral wall part, 24d… Opening, 25… Cover component, 26… Tubular sleeve, 28… Insertion part, 30… Resin, 32… Block, 33… Protective layer, 34… Block, 36… First sealing part, 38… Second sealing part, 40a, 40b… Outlet, 61… Water passage. Detailed Implementation

[0112] When “~” is used to indicate a range of values, the values ​​recorded before and after “~” are the lower limit and upper limit values, respectively.

[0113] In addition, in this invention, "any" and "at least a portion" have the same meaning.

[0114] 1. Hollow fiber membrane element

[0115] Hereinafter, an example of the hollow fiber membrane element of the present invention will be described with reference to the accompanying drawings. Furthermore, the dimensions and other dimensions shown in the illustrative figures in the following description are merely examples, and the present invention is not limited thereto, but can be implemented with appropriate modifications without altering its spirit.

[0116] 1.1 Structure of Hollow Fiber Membrane Elements

[0117] like Figure 1 and Figure 2 As shown, the hollow fiber membrane element 1 of this embodiment includes: a hollow fiber membrane 11, a water collection pipe, and outlets 40a and 40b for taking out treated water from the water collection pipe.

[0118] exist Figure 1 and Figure 2 In the hollow fiber membrane element 1 shown, the water collection pipe is composed of a first water collection pipe 12 having a first water collection channel 20e inside and a second water collection pipe 14 having a second water collection channel 20f inside. The first water collection pipe 12 and the second water collection pipe 14 are respectively arranged on opposite sides of the hollow fiber membrane 11 in the length direction of the hollow fiber membrane sheet 10 to which multiple hollow fiber membranes 11 are bundled. The ends of the first water collection pipe 12 and the second water collection pipe 14 are respectively connected to each other by a first tubular support 16 and a second tubular support 18.

[0119] In the hollow fiber membrane element 1, outlets 40a and 40b are formed at both ends along the long side of the second water collection pipe 14. The outlets can be located anywhere as long as they can remove the treated water collected in the water collection pipe via the hollow fiber membrane, and can also be located on a support column.

[0120] 1.2 Hollow Fiber Membrane

[0121] Hollow fiber membrane 11 is typically used as a hollow fiber membrane sheet 10 for bundling multiple hollow fiber membranes 11 into a sheet-like structure. A first water collection pipe 12 is disposed on the side of the first open end 10a of the hollow fiber membrane 11 in the longitudinal direction of the hollow fiber membrane sheet 10. A second water collection pipe 14 is disposed on the side of the second open end 10b of the hollow fiber membrane sheet 10 in the longitudinal direction, opposite to the first open end 10a.

[0122] A first tubular support 16 is disposed on one side of the hollow fiber membrane sheet 10 in the width direction. The first end 17a of the first tubular support 16 is connected to the first end 13a of the first water collection pipe 12, and the second end 17b of the first tubular support 16 is connected to the first end 15a of the second water collection pipe 14. A second tubular support 18 is disposed on the other side of the hollow fiber membrane sheet 10 in the width direction. The first end 19a of the second tubular support 18 is connected to the second end 13b of the first water collection pipe 12, and the second end 19b of the second tubular support 18 is connected to the second end 15b of the second water collection pipe 14.

[0123] The hollow fiber membrane element 1 can be configured such that the first water collection pipe 12 is the lower side and the second water collection pipe 14 is the upper side, and the length direction of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 is the vertical direction.

[0124] The hollow fiber membrane sheet 10 is formed by bundling multiple hollow fiber membranes 11 together in parallel. The number of hollow fiber membranes 11 in the hollow fiber membrane sheet 10 is not particularly limited, for example, 1000 to 6000, 2000 to 5000, etc., and can be appropriately set according to the membrane area.

[0125] In this example, the hollow fiber membrane sheet 10 is a laminate composed of multiple sheets arranged as a plurality of hollow fiber membranes 11. In this invention, the hollow fiber membrane sheet can be a laminate of multiple sheets or it can be composed of a single sheet.

[0126] Examples of materials that can be used for hollow fiber membranes include polysulfone resins, polyacrylonitrile, cellulose derivatives, polyethylene, polypropylene and other polyolefins, polyvinylidene fluoride (PVDF), polytetrafluoroethylene and other fluorinated resins, polyamides, polyesters, polymethacrylates, and polyacrylates. Additionally, materials in which substituents have been introduced into a portion of these resins can also be used. Hollow fiber membranes can be made from one or more materials.

[0127] For example, a hollow fiber membrane sheet can be formed and used by using multiple hollow fiber membranes 11 and the hollow fiber membrane sheet manufacturing method described in Japanese Patent No. 5919672.

[0128] 1.3 Water collection pipe

[0129] like Figure 3 As shown, the first water collecting pipe 12 includes: a pair of relatively long sidewall portions 20a and 20b whose surfaces face each other in the short side direction of the first water collecting pipe 12 and extend in the long side direction of the first water collecting pipe 12; and the ends of one of these sidewall portions 20a and 20b facing each other (in... Figure 3The bottom 20c of the first water collection pipe 12 has a semi-circular cross-section (with the lower ends connected to each other). The cross-section of the first water collection pipe 12, orthogonal to its long side, is U-shaped. A slit-like opening 20d is formed on the side of the first water collection pipe 12 opposite to the bottom 20c, and this opening 20d extends along the long side between the first end 13a and the second end 13b. The first open end 10a of the hollow fiber membrane sheet 10 is inserted into the opening 20d of the first water collection pipe 12.

[0130] On the inner side of the bottom 20c, there are a pair of wall surfaces 50a and 50b, spaced apart and extending opposite each other in the short side direction of the first water collection pipe 12, and a bottom surface 50c connecting the lower ends of the pair of wall surfaces 50a and 50b. The wall surfaces 50a and 50b are arranged with a maximum length W between them in the short side direction of the first water collection pipe 12. The cross-sectional shape of the bottom surface 50c, perpendicular to the long side direction of the first water collection pipe 12, is a semicircle with a radius of W / 2.

[0131] like Figure 3 As shown, the first open end 10a of the hollow fiber membrane sheet 10 is inserted into the opening 20d of the first water collection pipe 12 while it is housed in the casting housing 23 and fixed to the casting housing 23 by a casting portion 23b made of a hardened casting resin. The casting housing 23 is fixed to the first water collection pipe 12 by a casting portion 22a made of a hardened casting resin. Furthermore, the portion of the first open end 10a of the hollow fiber membrane sheet 10 on the opening 20d side compared to the casting housing 23 is fixed to the first water collection pipe 12 by a casting portion 23a made of a hardened casting resin.

[0132] In this way, the hollow fiber membrane 11 and the first water collection pipe 12 are fixed by the casting portions 22a, 23a, and 23b. Furthermore, the bottom 20c side of the first water collection pipe 12, compared to the casting portions 22a and 23b, forms the first water collection path 20e (water collection path). That is, the first water collection pipe 12 has a first water collection path 20e inside, with the casting portions 22a and 23b and the first water collection pipe 12 as its walls.

[0133] In the first open end 10a of the hollow fiber membrane sheet 10, the interior of each hollow fiber membrane 11 is connected to the first water collection channel 20e of the first water collection pipe 12.

[0134] The cross-sectional area of ​​any first water collection channel 20e perpendicular to the long side of the first water collection pipe 12 is 100 mm². 2 ~350mm 2 Preferably 150mm 2 ~300mm 2 More preferably 250mm 2 ~280mm2 By controlling the cross-sectional area within this range, the increase in flow resistance can be kept within an acceptable range, while ensuring excellent pressure resistance.

[0135] As the first water collection pipe 12, it is preferable that the cross-sectional area of ​​the first water collection path 20e is within the aforementioned range at any position along the long side of the first water collection pipe 12. However, this is not a limitation; the first water collection pipe 12 may also have only a portion of the cross-sectional area along the long side of the first water collection path 20e within the aforementioned range.

[0136] The length H (also called the height H of the water collection path) of the hollow fiber membrane 11 in the longitudinal direction of the water collection path section perpendicular to the long side of the first water collection pipe 12 is preferably 20 mm or less, more preferably 15 to 20 mm, even more preferably 16 to 20 mm, and particularly preferably 17 to 19 mm. Furthermore, as... Figure 3 As shown, the aforementioned length H is the distance along the length of the hollow fiber membrane 11 of the first water collection pipe 12, perpendicular to the long side, from the end face of the casting portion 23b in contact with the wall surfaces 50a and 50b on the side of the bottom surface 50c to the bottom surface 50c.

[0137] When the height H of the water collection channel is less than 20mm, the pressure resistance can be further improved, so that even if backwashing is carried out under high pressure, it is difficult for water to leak.

[0138] The maximum length W of the short-side spacing in walls 50a and 50b preferably satisfies the relationship H ≤ 1.2 × W with respect to the height H of the water collection channel. Within this range, it becomes easier to suppress water retention.

[0139] Furthermore, when the maximum length W of the water collection channel increases, more membranes can be placed in the water collection pipe, thereby increasing the amount of water that can be processed per unit time. Moreover, it facilitates the renewal of the water inside the water collection pipe, allowing water accumulated at the bottom of the water collection channel to flow out and improving water quality.

[0140] like Figures 3A to 3H As shown, as another means to improve the pressure resistance of the first water collection pipe 12, a deformation suppression member 21a can be provided to suppress the deformation of the wall of the first water collection pipe 12. Furthermore, a member 21 supporting the deformation suppression member 21a can be further provided. With the deformation suppression member 21a, even under high-pressure backwashing, deformation of the water collection path expanding outwards can be suppressed, thereby further improving pressure resistance and making leakage even more difficult. In addition, by providing the deformation suppression member 21a, even if the hollow fiber membrane element 1 is impacted, only the deformation suppression member 21a will break, while the water collection path is less likely to be damaged.

[0141] The deformation suppression component 21a is preferably configured to extend for more than 70% of the length along the long side of the first water collection pipe 12.

[0142] As a deformation suppression component 21a, a reinforcing rib is preferred, but any reinforcing component other than a rib may be used as long as it can suppress the deformation of the wall of the first water collection pipe 12.

[0143] like Figure 3A , Figure 3B , Figures 3F to 3H As shown, the deformation suppression component 21a can be disposed on the outside of the first water collection pipe 12, such as... Figures 3C to 3E As shown, the deformation suppression component 21a can also be disposed on the inner side of the first water collection pipe 12, that is, on the side of the first water collection channel 20e.

[0144] In addition, the deformation suppression component 21a can be provided as a component that is different from the first water collection pipe 12 and is connected to the wall of the water collection pipe, or it can be connected to the first water collection pipe 12 and integrated into it.

[0145] like Figures 3A to 3H As shown, in the cross-section of the first water collection pipe 12 perpendicular to its long side, the deformation suppression member 21a is formed with a width not exceeding the maximum width defined by the distance between the outer sides of the pair of sidewall portions 20a, 20b. Therefore, the first water collection pipe 12 with the deformation suppression member 21a does not increase the overall size. For example, even if it is impacted during maintenance work, damage can be suppressed due to structural reinforcement, and the deformation suppression member 21a absorbs the impact during the collision, thereby allowing the damaged part to be replaced by the deformation suppression member 21a instead of the water collection pipe.

[0146] like Figure 3 As shown, the first water collection pipe 12 preferably has a step 20g on the inner surface of a pair of sidewall portions 20a, 20b, and the surface of the step 20g facing the opening 20d joins the lower part of the casting portion 22a. When such a step 20g is present, the shear direction of the joint range increases relative to the force that the wall of the water collection channel wants to expand outward under pressure, which is therefore preferred. In addition, since the joint area is increased, the joint force is improved, and thus the joint strength between the water collection pipe and the casting portion is increased, thereby easily suppressing the joint from peeling off due to impact during collision.

[0147] The width of the step 20g on the short side of the first water collection pipe 12 is preferably 0.5 mm or more, more preferably 1.5 mm or more, and even more preferably 2.0 mm to 3.0 mm.

[0148] The surface roughness of the mating surface between the first water collecting pipe 12 and the casting part 22a is preferably Ra 6.3 to 25, as defined by JIS B 0601:2001, using the arithmetic mean roughness Ra. When the surface roughness is within this range, the bonding strength between the first water collecting pipe 12 and the casting part 22a is further increased, and the durability of the hollow fiber membrane element 1 is further improved, thereby easily withstanding multiple high-pressure backwashings. In addition, the increased bonding strength between the water collecting pipe and the casting part makes it easier to suppress the peeling of the joint due to impact during collisions.

[0149] Surface roughening can be divided into two types: roughening of the main body of the water collection pipe and roughening of the forming mold of the water collection pipe. Examples of roughening methods for the main body of the water collection pipe include sandblasting and filing, while examples of roughing methods for the forming mold include shot peening and chemical etching.

[0150] The mating surface between the first water collecting pipe 12 and the casting portion 22a preferably has unevenness. When the mating surface has unevenness, the bonding strength between the first water collecting pipe 12 and the casting portion 22a is further increased, and the durability of the hollow fiber membrane element 1 is further improved, thereby making it easier to withstand multiple high-pressure backwashings. In addition, the increased bonding strength between the water collecting pipe and the casting portion makes it easier to prevent the joint from peeling off due to impact during collisions.

[0151] The unevenness of the mating surface can be square, wavy, or other shapes. Furthermore, the height (difference between high and low points) of the unevenness is preferably 0.3 mm to 1.0 mm, more preferably 0.4 mm to 0.6 mm. When the unevenness is within this range, the bonding force of the casting liquid applied to the mating surface can be improved, and it is easier to prevent the casting liquid from flowing into the water collection channel during injection, therefore this is preferred.

[0152] The above description of the first water collection pipe 12 in "1.3 Water Collection Pipe" includes the shape of inserting the open end of the hollow fiber membrane sheet into the water collection pipe, the cross-sectional area of ​​the water collection path, etc., which also correspond to the second water collection pipe 14. Furthermore, in the hollow fiber membrane element 1, the second water collection pipe 14 is arranged on the side of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 opposite to the side of the first water collection pipe 12 in the longitudinal direction, i.e., with the opening facing downwards. The second open end 10b of the hollow fiber membrane sheet 10 is fixed by the casting section with the end face of each hollow fiber membrane 11 open, inserted into the slit-like opening of the second water collection pipe 14.

[0153] The first water pipe 12 and the second water pipe 14 can be of the same form or different forms, but it is preferred that they are of the same form.

[0154] For the material of the water collection pipe, materials with excellent mechanical strength and durability are preferred, such as polycarbonate, polysulfone, polyolefin, PVC (polyvinyl chloride), acrylic resin, ABS resin, modified PPE (polyphenylene oxide), etc. The water collection pipe can be made of one material or two or more materials.

[0155] Examples of casting resins used to form the casting portion include epoxy resin, unsaturated polyester resin, polyurethane resin, silicone-based filler materials, and various hot-melt resins. The casting resin used to form the casting portion can be one type or two or more types.

[0156] 1.4 pillars

[0157] Figure 4 yes Figure 1 BB cross-sectional view of a hollow fiber membrane element.

[0158] like Figure 4 As shown, the first tubular support 16 has an internal water passage 61 for water supply. The water passage 61 inside the first tubular support 16, the first water collection passage 20e inside the first water collection pipe 12, and the second water collection passage 20f inside the second water collection pipe 14 are connected. Similarly, the second tubular support 18 has an internal water passage for water supply. The water passage inside the second tubular support 18, the first water collection passage 20e inside the first water collection pipe 12, and the second water collection passage 20f inside the second water collection pipe 14 are connected.

[0159] The cross-sectional area of ​​the water collection passage of the water collection pipe is preferably less than or equal to the cross-sectional area of ​​the water passage of the support column. If the cross-sectional area of ​​the water collection passage of the water collection pipe is larger than that of the water passage of the support column (in other words, if the cross-sectional area of ​​the water passage of the support column is smaller than that of the water collection passage of the water collection pipe), the suction pressure when the treated water recovered from the hollow fiber membrane is concentrated into the water collection passage via the water passage by the operation of a suction pump or the like may be lost in the water passage and not be sufficiently applied to the water collection passage, resulting in reduced permeability. On the other hand, when the cross-sectional area of ​​the water collection passage of the water collection pipe is less than or equal to that of the water passage of the support column, pressure loss in the water passage is easily suppressed, and permeability is maintained.

[0160] In this way, by making the cross-sectional area of ​​the water collection channel in the plane perpendicular to the long side of the water collection pipe less than the cross-sectional area of ​​the water passage, pressure loss in the water passage can be easily suppressed, thus maintaining permeability. In addition, the cross-sectional area of ​​the water collection channel can be ensured without changing the size of the hollow fiber membrane element, and there is dimensional leeway in the height direction. Therefore, it is easy to install deformation suppression components at the lower part of the water collection channel or water collection pipe.

[0161] Let 'a' be the cross-sectional area of ​​any face perpendicular to the long side of the water passage of the support column, and let 'b' be the cross-sectional area of ​​any face perpendicular to the long side of the water collection pipe. Preferably, the relationship 0.5 × a ≤ b is satisfied. If the cross-sectional area b of the water collection path is smaller than 0.5 × a, there is a possibility of significant pressure loss in the water collection path, leading to reduced permeability. Therefore, by satisfying the relationship 0.5 × a ≤ b, it is easier to maintain the permeability of each hollow fiber membrane 11.

[0162] The ratio of the cross-sectional area a of the water passage 61 of the first tubular support 16 to the cross-sectional area b1 of the first water collection passage 20e of the first water collection pipe 12, and the ratio a / b2 of the cross-sectional area a of the water passage 61 of the first tubular support 16 to the cross-sectional area b2 of the second water collection passage 20f of the second water collection pipe 14, are preferably 0.7 or more, more preferably 0.9 or more, and preferably satisfy both formula (1) and formula (2).

[0163] a / b1≥0.9···(1)

[0164] a / b²≥0.9···(2)

[0165] By making the ratios a / b1 and a / b2 both 0.7 or higher, the pressure loss of the water passage 61 of the first tubular support 16 in the hollow fiber membrane element 1 is more easily reduced, which is therefore preferred.

[0166] The ratio of the cross-sectional area of ​​the water passage of the second tubular support 18 to the cross-sectional area of ​​the first water collection passage 20e of the first water collection pipe 12, and the ratio of the cross-sectional area of ​​the water passage of the second tubular support 18 to the cross-sectional area of ​​the second water collection passage 20f of the second water collection pipe are also the same.

[0167] The cross-sectional area a of the water passage 61 of the first tubular support 16, the cross-sectional area b1 of the first water collection passage 20e of the first water collection pipe 12, and the cross-sectional area b2 of the second water collection passage 20f of the second water collection pipe 14 are further preferably satisfied simultaneously by formulas (3) and (4). As a result, it is easier to maintain the water permeability of each hollow fiber membrane 11.

[0168] 0.5×a≤b1···(3)

[0169] 0.5×a≤b2···(4)

[0170] The cross-sectional area of ​​the water passage, which serves as a support, can be set to, for example, 150mm². 2 ~400mm 2 .

[0171] There are no particular limitations on the shape of a pillar; examples include quadrilateral cylinders and cylindrical shapes.

[0172] There are no particular restrictions on the material used for the support pillars; examples include stainless steel (SUS).

[0173] 1.5 protrusion

[0174] like Figure 4 and Figure 5 As shown, the first end 13a of the first water collecting pipe 12 includes: a cylindrical portion 24a communicating with the first water collecting passage 20e; a tubular protrusion 24b protruding towards the opening 20d of the cylindrical portion 24a; and a peripheral wall portion 24c surrounding the protrusion 24b. Two of the four peripheral wall portions 24c, which are protrusions 24b on the cylindrical portion 24a, are separated from the protrusions 24b on both sides of the first water collecting pipe 12 along the long side and face each other. The remaining two of the four peripheral wall portions 24c, which are protrusions 24b on the cylindrical portion 24a, are separated from the protrusions 24b on both sides of the first water collecting pipe 12 along the short side and face each other, respectively forming a continuous wall integral with the side wall portions 20a and 20b.

[0175] The upper end of the peripheral wall portion 24c of the first water collecting pipe 12, located on the central side along the long side of the four peripheral wall portions 24c surrounding the protrusion 24b, that is, on the side near the first opening end 10a of the hollow fiber membrane sheet 10, is slightly lower than the upper ends of the side wall portions 20a and 20b. Furthermore, the upper ends of the remaining three peripheral wall portions 24c, namely the peripheral wall portion 24c on the end face side of the first water collecting pipe 12 and the opposing pair of peripheral wall portions 24c along the short side, are at the same height as the upper ends of the side wall portions 20a and 20b.

[0176] The tubular protrusion 24b located at the first end 13a of the first water collection pipe 12 is for connecting to the first tubular support 16. The interior of the protrusion 24b communicates with the interior of the cylindrical portion 24a. The shape of the protrusion 24b is not particularly limited, and examples include, for example, a quadrilateral cylindrical shape or a cylindrical shape.

[0177] The height of the protrusion 24b is preferably 5 to 30 mm, more preferably 10 to 20 mm. If the height of the protrusion 24b is above the lower limit of the above range, it is easier to improve the connection strength between the protrusion 24b and the first tubular support 16. If the height of the protrusion 24b is below the upper limit of the above range, it is beneficial to the formability.

[0178] The second end 13b of the first water collection pipe 12 has the same shape as the first end 13a, and has a tubular protrusion for connecting to the second tubular support 18. The preferred shape is also the same.

[0179] The shapes of the first end 15a and the second end 15b of the second water collection pipe 14 can also be listed as the same as those of the second end 13b of the first water collection pipe 12, and the preferred shapes are also the same.

[0180] 1.6 Outlet

[0181] An outlet for discharging treated water is formed on the end face of at least one of the first water collection pipe 12 and the second water collection pipe 14. In this example, the opening 24d of the cylindrical portion 24a on the end face of the first end 13a side of the first water collection pipe 12 is closed by the cover member 25. The opening on the end face of the water collection pipe can also be used as an outlet for discharging treated water without being closed by the cover member.

[0182] 1.7 Tubular sleeve

[0183] exist Figure 4 and Figure 5 In this configuration, the protrusion 24b of the first end 13a of the first water collection pipe 12 is inserted into the first end 17a of the first tubular support 16 while the tubular sleeve 26 is installed. However, the tubular sleeve 26 can also be omitted. Alternatively, the tubular sleeve 26 can be integrally formed with the first water collection pipe.

[0184] With the tubular sleeve 26 installed, the first end 17a of the first tubular support 16 and the first water collection passage 20e of the first water collection pipe 12 are connected via the protrusion 24b and the tubular sleeve 26, and the first end 13a of the first water collection pipe 12 are connected.

[0185] Similarly, the protrusion of the second end 13b of the first water collection pipe 12 can be inserted into the first end 19a of the second tubular support 18 while a tubular sleeve is installed. With the first water collection passage 20e inside the second tubular support 18 connected to the first water collection pipe 12 via the protrusion and the tubular sleeve, the first end 19a of the second tubular support 18 is connected to the second end 13b of the first water collection pipe 12. The tubular sleeve can be omitted. Alternatively, the tubular sleeve 26 can be integrally formed with the second water collection pipe.

[0186] Alternatively, the protrusion of the first end 15a of the second water collection pipe 14 can be inserted into the second end 17b of the first tubular support 16 while a tubular sleeve is installed. In the state where the second water collection passage 20f inside the first tubular support 16 and the second water collection pipe 14 is connected through the protrusion and the tubular sleeve, the second end 17b of the first tubular support 16 is connected to the first end 15a of the second water collection pipe 14.

[0187] Alternatively, the protrusion of the second end 15b of the second water collection pipe 14 can be inserted into the second end 19b of the second tubular support 18 while a tubular sleeve is installed. With the second water collection passage 20f inside the second tubular support 18 and the second water collection pipe 14 connected through the protrusion and the tubular sleeve, the second end 19b of the second tubular support 18 and the second end 15b of the second water collection pipe 14 are connected.

[0188] 1.8 resin

[0189] Resin 30 is filled around the first end 17a of the first tubular support 16 on the inner side of the peripheral wall 24c of the first end 13a of the first water collection pipe 12. Thus, the insertion portion 28 of the first tubular support 16 is fixed in a watertight state by the resin 30 in such a way that its interior and exterior are isolated.

[0190] Preferably, the gap between the first tubular support 16 in the insertion portion 28 and the protrusion 24b is watertightly sealed with resin 30.

[0191] There are no particular limitations on resin 30, and any known curing resin can be used without particular restriction. From the viewpoint of higher bonding strength with tubular supports and excellent water tightness, a hard resin with a Shore A hardness of 80 or higher as measured by JIS C 2105 is preferred as resin 30. When resin 30 is used as a hard resin, from the viewpoint of minimizing the risk of partial breakage, a Shore A hardness of 99 or lower is preferred. Furthermore, a soft resin with a Shore A hardness less than 80 can also be used as resin 30.

[0192] Examples of rigid resins include epoxy resins, unsaturated polyester resins, polyurethane resins, silicone-based fillers, and various hot-melt resins.

[0193] Examples of soft resins include polyurethane resins, silicone-based fillers, and various hot-melt resins.

[0194] The protrusion 24b preferably tapers towards its tip. This facilitates the insertion of the first tubular support 16 and prevents the resin 30 injected around the protrusion 24b from peeling off during insertion of the first tubular support 16. Furthermore, demolding during injection molding of the first water collection pipe 12 becomes easier.

[0195] The outer surface of the first end 17a of the first tubular support 16 is preferably sandblasted. In this invention, the outer surfaces of the ends of the first and second tubular supports are preferably sandblasted. The protrusions on the outer surfaces of the ends of the first and second tubular supports are inserted into the insertion portions within their ends, which are in contact with resin that watertightly seals and fixes the insertion portions in a manner that isolates the communicating interior and exterior of the insertion portions. By sandblasting the outer surfaces of the ends of the first and second tubular supports, the adhesion between the tubular supports and the resin can be improved, thereby increasing the strength of the hollow fiber membrane element.

[0196] There are no particular limitations on the methods of sandblasting.

[0197] 1.9 yuan

[0198] Furthermore, in this example, blocks 32 and 34 are provided on both sides of the long side of the first end 17a of the first tubular support 16, inside the peripheral wall portion 24c of the first water collection pipe 12. Blocks 32 and 34 are installed with resin 30 embedded and filled inside the peripheral wall portion 24c. Therefore, even when a load is applied to the support, it is possible to prevent the support from collapsing and breaking.

[0199] As a block, there are no particular limitations; examples include cylindrical and columnar shapes.

[0200] There are no particular limitations on the material of the block; for example, the same material as that listed as the material of the water pipe can be used.

[0201] Alternatively, a portion of the water collection pipe can be formed into a cuboid component through integral molding, thus having the same function as a block.

[0202] Furthermore, in this invention, it is preferable that a first blocking portion is provided on the long side of the first water collection pipe, closer to the first end of the hollow fiber membrane than the first open end of the hollow fiber membrane. This first blocking portion cuts off the flow of treated water flowing into the water collection path of the first water collection pipe through the first open end of the hollow fiber membrane towards the first tubular support. Similarly, a second blocking portion is provided on the long side of the second water collection pipe, closer to the second end of the hollow fiber membrane than the second open end of the hollow fiber membrane. This second blocking portion cuts off the flow of treated water flowing into the water collection path of the second water collection pipe through the second open end of the hollow fiber membrane towards the second tubular support. This prevents deviation of the treatment portion of the hollow fiber membrane, enabling efficient use of the hollow fiber membrane as a whole for treatment.

[0203] For example, in this case, such as Figure 2As shown, a first sealing portion 36 and a second sealing portion 38 are respectively provided on the side of the first water collection pipe 12 relative to the first opening end 10a of the hollow fiber membrane 10, and on the side of the second water collection pipe 14 relative to the second opening end 10b of the hollow fiber membrane 10, respectively. Furthermore, outlets 40a and 40b for extracting treated water are formed on the end faces of the first end 15a and the second end 15b of the second water collection pipe 14.

[0204] The first blocking section 36 cuts off the flow of treated water into the first water collection channel 20e through the first opening end 10a of the hollow fiber membrane 10 and towards the first tubular support 16. The second blocking section 38 cuts off the flow of treated water into the second water collection channel 20f through the second opening end 10b of the hollow fiber membrane 10 and towards the second tubular support 18.

[0205] The form of the first sealing section 36 and the second sealing section 38 is not particularly limited as long as it can cut off the flow of the treated water.

[0206] like Figure 2 As shown, in this manner, treated water collected from the lower portions of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 into the first water collection path 20e of the lower first water collection pipe 12 is sent through the second tubular support 18 to the second end 15b of the upper second water collection pipe 14, and is then removed from the outlet 40b. Conversely, treated water collected from the upper portions of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 into the second water collection path 20f of the upper second water collection pipe 14 is sent to the first end 15a of the second water collection pipe 14, and is then removed from the outlet 40a. Thus, the hollow fiber membrane sheet 10 as a whole can be used efficiently for treatment.

[0207] Additionally, for example, such as Figure 6 As shown, it can also be configured such that a first sealing part 36 is provided at the center of the long side of the first water collection pipe 12, a second sealing part 38 is provided at the center of the long side of the second water collection pipe 14, and outlets 40a and 40b for taking out treated water are formed at the end faces of the first end 15a and the second end 15b of the second water collection pipe 14.

[0208] In this structure, the first blocking part 36 cuts off the flow of treated water into the first water collection channel 20e through the first open end 10a of the hollow fiber membrane 10 at the first end 13a side towards the second end 13b side, and also cuts off the flow of treated water into the first water collection channel 20e through the first open end 10a of the hollow fiber membrane 10 at the second end 13b side towards the first end 13a side. The second blocking part 38 cuts off the flow of treated water into the second water collection channel 20f through the second open end 10b of the hollow fiber membrane 10 at the first end 15a side towards the second end 15b side, and also cuts off the flow of treated water into the second water collection channel 20f through the second open end 10b of the hollow fiber membrane 10 at the second end 15b side towards the first end 15a side.

[0209] In this way, such as Figure 6 As shown, treated water collected from the lower portions of the hollow fiber membranes 11 of the hollow fiber membrane sheets 10 at the first end 13a side, flowing into the first water collection path 20e of the lower first water collection pipe 12, is sent through the first tubular support 16 to the first end 15a of the upper second water collection pipe 14, and is then removed from the outlet 40a. Conversely, treated water collected from the upper portions of the hollow fiber membranes 11 of the hollow fiber membrane sheets 10 at the first end 13a side, flowing into the second water collection path 20f of the upper second water collection pipe 14, is sent to the first end 15a of the second water collection pipe 14, and is then removed from the outlet 40a.

[0210] Furthermore, treated water collected from the lower portions of the hollow fiber membranes 11 of the hollow fiber membrane sheets 10 at the second end 13b side into the first water collection path 20e of the lower first water collection pipe 12 is sent through the second tubular support 18 to the second end 15b of the upper second water collection pipe 14, and is then removed from the outlet 40b. Similarly, treated water collected from the upper portions of the hollow fiber membranes 11 of the hollow fiber membrane sheets 10 at the second end 13b side into the second water collection path 20f of the upper second water collection pipe 14 is sent to the second end 15b of the second water collection pipe 14, and is then removed from the outlet 40b. Thus, the hollow fiber membrane sheets 10 can be used efficiently for treatment as a whole.

[0211] Furthermore, the hollow fiber membrane element of the present invention is not limited to the hollow fiber membrane element 1 described above.

[0212] For example, the number and location of the exits are not limited to the above-mentioned numbers and locations, and can be set appropriately.

[0213] Hollow fiber membrane elements can also be used with each hollow fiber membrane configured as a hollow fiber membrane sheet having its length direction in the horizontal direction.

[0214] 2. Manufacturing method of hollow fiber membrane elements

[0215] The manufacturing method of the hollow fiber membrane element of the present invention is not particularly limited. Hereinafter, the manufacturing method of the hollow fiber membrane element 1 described above will be described as an example of the manufacturing method of the hollow fiber membrane element of the present invention.

[0216] As a method for manufacturing hollow fiber membrane element 1, a method having the following steps (a) to (e) can be listed.

[0217] Step (a): Insert the first and second ends of the multiple hollow fiber membranes 11 bundled into sheet form into the casting shell, inject casting resin and harden it, thereby fixing the hollow fiber membrane sheet to the casting shell.

[0218] Step (b): Cut off the top part of the casting shell that fixes the hollow fiber membrane 11 to obtain the hollow fiber membrane sheet 10.

[0219] Process (c): Connect the first tubular support 16 and the second tubular support 18 to the protrusions at the first end 13a and the second end 13b of the first water collection pipe 12.

[0220] Process (d): Connect the first tubular support 16 and the second tubular support 18 to the protrusions at the first end 15a and the second end 15b of the second water collection pipe 14.

[0221] Step (e): Insert the first open end 10a of the hollow fiber membrane 10 into the first water collection pipe 12 and fix it by the casting part; insert the second open end 10b of the hollow fiber membrane 10 into the second water collection pipe 14 and fix it by the casting part.

[0222] Deformation suppression components may be installed in the water collection pipe as needed.

[0223] 3. Hollow fiber membrane module

[0224] The hollow fiber membrane module of the present invention comprises a plurality of hollow fiber membrane elements of the present invention. In addition to comprising a plurality of hollow fiber membrane elements of the present invention, the hollow fiber membrane module of the present invention can be employed in a known manner.

[0225] In the hollow fiber membrane assembly of the present invention, for example, multiple hollow fiber membrane elements can be arranged such that their hollow fiber membrane sheet faces each other and are spaced apart in a direction perpendicular to the surface of the hollow fiber membrane sheet. Alternatively, multiple units in which multiple hollow fiber membrane elements are arranged in this manner can be formed and these multiple units can be stacked one on top of the other.

[0226] 4. Effects

[0227] The hollow fiber membrane element of the present invention has a water collection path cross-sectional area of ​​100-350 mm² on the plane perpendicular to the long side of the water collection pipe. 2 This gives it excellent pressure resistance. Therefore, even when pressure is applied to the water collection pipe during high-pressure backwashing, it can prevent water leakage caused by pipe rupture.

[0228] The hollow fiber membrane element and hollow fiber membrane module of the present invention are not particularly limited in their applications; they can be used for wastewater treatment, as well as for the production of sterile water, drinking water, highly pure water, and other purified water. The hollow fiber membrane element of the present invention has excellent pressure resistance capable of withstanding backwashing, and is therefore particularly suitable for the production of purified water.

[0229] 5. Water treatment equipment

[0230] The water treatment apparatus of the present invention includes the hollow fiber membrane module of the present invention and an air dissipation device disposed below the hollow fiber membrane module.

[0231] There are no particular limitations on the gas dissipation device; any known gas dissipation device for membrane cleaning can be used without restriction.

[0232] As examples of the water treatment apparatus of the present invention, apparatuses for membrane separation activated sludge (MBR) and water purification apparatuses for treating river water can be exemplified.

[0233] 6. Water treatment methods

[0234] The water treatment method of the present invention is a method of treating water using the water treatment apparatus of the present invention. There are no particular limitations to the water treatment method of the present invention; examples include, for instance, membrane sludge reprocessing (MBR) and river water purification.

[0235] Example

[0236] The present invention will be specifically described below through examples, but the present invention is not limited to the following description.

[0237] [Example 1]

[0238] Made with Figures 1-3 The hollow fiber membrane element is of the same morphology as the hollow fiber membrane element 1 in the example.

[0239] The cross-sectional area b1 of the first water collection channel of the first water collection pipe and the cross-sectional area b2 of the second water collection channel of the second water collection pipe are both set to 300mm. 2 Set the height H of the first and second water collection channels to 18mm respectively, and set the ratios a / b1 and a / b2 to 1.28 respectively.

[0240] [Example 2]

[0241] The production process involved changing the shape of the first and second water collection pipes to have... Figure 3A The deformation suppression component in the example is a hollow fiber membrane element with the same shape as in Example 1, except for the cross-sectional area, height H, ratio a / b1, and ratio a / b2 of the first and second water collection channels, as shown in Table 1.

[0242] [Example 3]

[0243] The production process involved changing the shape of the first and second water collection pipes to have... Figure 3A The deformation suppression component in the example is a hollow fiber membrane element with the same shape as in Example 1, except for the cross-sectional area, height H, ratio a / b1, and ratio a / b2 of the first and second water collection channels, as shown in Table 1.

[0244] [Comparative Example 1]

[0245] The production process involved changing the shape of the first and second water collection pipes to have... Figure 3A The hollow fiber membrane element in the example is a hollow fiber membrane element with the same shape as in Example 1, except that the cross-sectional area and height H of the first and second water collection channels are changed as shown in Table 1 without the support pillar.

[0246] [Comparative Example 2]

[0247] Hollow fiber membrane elements with the same shape as in Example 1 were fabricated, except that the cross-sectional area, height H, ratio a / b1, and ratio a / b2 of the first and second water collection channels were changed as shown in Table 1.

[0248] [Pressure Resistance Test]

[0249] In each example of the hollow fiber membrane element, the hollow fiber membrane is cut at the opening of the first and second water collection pipes, and these cut portions are sealed by resin injection. Next, water is supplied to each water collection pipe, causing the water pressure to gradually increase until the water collection pipe ruptures and leakage occurs. Table 1 shows the water pressure at the moment leakage occurs in each example of the hollow fiber membrane element.

[0250] Table 1

[0251]

[0252] As shown in Table 1, the hollow fiber membrane elements of Examples 1-3, whose cross-sectional area of ​​the water collection pipe is within an appropriate range, exhibit higher water pressure at the time of leakage and better pressure resistance compared to the hollow fiber membrane elements of Comparative Example 1 (with a smaller cross-sectional area of ​​the water collection pipe) and Comparative Example 2 (with a larger cross-sectional area of ​​the water collection pipe). Furthermore, the hollow fiber membrane elements of Examples 2 and 3, which have deformation-inhibiting components, exhibit better pressure resistance compared to the hollow fiber membrane element of Example 1 (which does not have deformation-inhibiting components).

Claims

1. A hollow fiber membrane element having a hollow fiber membrane, a header, and a take-out port for taking out treated water from the header, characterized in that, the hollow fiber membrane and the header are fixed by a cast portion, an internal portion of the header has a header passage that uses the cast portion and the header as a wall surface, an end portion of the hollow fiber membrane communicates with the header, the header is composed of a first header and a second header, the second header is located on the opposite side of the first header in the longitudinal direction of the hollow fiber membrane, and the first header and the second header are connected by a support, a water passage in the internal portion of the support communicates with a first header passage of the first header and a second header passage of the second header, respectively, when the cross-sectional area of any surface of the header passage perpendicular to the longitudinal direction is set as b, and the cross-sectional area of any surface of the water passage of the support perpendicular to the longitudinal direction is set as a, the relationship of 0.5 x a < b is satisfied, and the following formulas (1) and (2) are satisfied: a / b1 > 0.9 (1) a / b2 > 0.9 (2) wherein b1 is the cross-sectional area of any surface of the first header passage perpendicular to the longitudinal direction, b2 is the cross-sectional area of any surface of the second header passage perpendicular to the longitudinal direction, the maximum length between the wall surfaces of the header opposite each other in the short direction of the header is set as W, the maximum length of the longitudinal direction of the hollow fiber membrane perpendicular to the longitudinal direction of the header from the portion of the cast portion in contact with the wall surface farthest from the bottom surface of the header passage to the bottom surface is set as H, the following relationship is satisfied: H < 1.2 x W, and the length of the longitudinal direction of the hollow fiber membrane in the header passage cross-section is 15 to 20 mm.

2. The hollow fiber membrane element according to claim 1, characterized in that, the length of the longitudinal direction of the hollow fiber membrane in the header passage cross-section is 16 to 20 mm.

3. The hollow fiber membrane element according to claim 1, characterized in that, at least one of a deformation suppression member in contact with the wall of the header and a deformation suppression member integrated with the header is provided.

4. The hollow fiber membrane element according to claim 3, characterized in that, the deformation suppression member is a rib. The cross-sectional area of any water collecting path cross section of the water collecting pipe perpendicular to the long side direction is 100 to 350 mm 2 , 5. The hollow fiber membrane element according to any one of claims 1 to 4, characterized in that, the header has a step, and the step is engaged with the lower portion of the cast portion.

6. The hollow fiber membrane element according to claim 5, characterized in that, the step is 0.5 to 3 mm.

7. The hollow fiber membrane element according to claim 1, characterized in that, the following formulas (3) and (4) are satisfied: 0.5 x a < b1 (3) 0.5 x a < b2 (4).

8. The hollow fiber membrane element according to claim 1, characterized in that, the length of the longitudinal direction of the hollow fiber membrane in the header passage cross-section is 17 to 19 mm. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 9. A hollow fiber membrane module characterized by comprising: a plurality of the hollow fiber membrane elements according to any one of claims 1 to 8.

10. A water treatment apparatus characterized by comprising: the hollow fiber membrane module according to claim 9 and a diffuser disposed below the hollow fiber membrane module.

11. A water treatment method characterized by comprising: using the water treatment apparatus according to claim 10.

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