Water treatment device, filtration method, and leak repair method

Abstract

Provided is a water treatment device which has fewer constituent elements than in the prior art, can reduce the time required for installation, and can save space. A water treatment device provided with one or more units comprising: a hollow fiber membrane module group (110) comprising three or more and ten or less hollow fiber membrane modules (100) each comprising a hollow fiber membrane bundle comprising a plurality of hollow fiber membranes; a pipe group (120) comprising a raw water feed pipe (121) connected to the hollow fiber membrane module (100) via a raw water inlet, a filtrate collection pipe (122) connected to the hollow fiber membrane module (100) via a filtrate outlet, and a discharged water recovery pipe (123) connected to the hollow fiber membrane module (100) via a cleaning outlet; and a support member group (130) comprising support members (131, 132) for supporting the hollow fiber membrane module (100), the raw water delivery pipe (121), the filtered water collection pipe (122), and the discharged water collection pipe (123), in which the mass per unit membrane area of the hollow fiber membrane is 1.0 kg / m2 or less.

Description

Technical Field

[0001] The present invention relates to a water treatment device, a filtering method and a leakage repair method. More specifically, the present invention relates to a hollow fiber membrane module water treatment device optimized as a prefabricated water treatment device, a filtering method and a leakage repair method. Background Art

[0002] In the water treatment for obtaining drinking water, industrial water, etc. from natural water sources such as river water, lake water, groundwater, etc. that are suspended water, a solid-liquid separation operation (de-turbidity operation) for removing suspended matter is necessary. In addition, in the sewage treatment for treating domestic drainage such as sewage to produce recycled water or to make it dischargeable clean water, a solid-liquid separation operation (de-turbidity operation) for removing suspended matter is also necessary. The necessary de-turbidity operation mainly includes: with respect to water treatment, removal of turbid matter (clay, colloid, bacteria, etc.) from natural water source water that is suspended water; with respect to sewage treatment, removal of suspended matter in sewage, and removal of suspended matter (sludge, etc.) in treated water after biological treatment (secondary treatment) using activated sludge, etc.

[0003] In the past, these turbidity removal operations were mainly performed by sedimentation, sand filtration, coagulation sedimentation sand filtration, etc. However, in recent years, membrane filtration has gradually become popular. The advantages of membrane filtration are (1) The turbidity removal level of the obtained water is high and stable, so the safety of the obtained water is high; (2) The installation space required for the filtration device is small; and (3) Easy to operate automatically wait.

[0004] For example, in water treatment, membrane filtration has been used as an alternative to coagulation sedimentation sand filtration or as a method for further improving the quality of treated water after coagulation sedimentation sand filtration in the later stage of coagulation sedimentation sand filtration. In sewage treatment, the use of membrane filtration to separate sludge from secondary sewage treatment water is being studied. In these turbidity removal operations based on membrane filtration, hollow fiber ultrafiltration membranes and microfiltration membranes (average pore diameters in the range of several nm to several hundred nm) are mainly used.

[0005] As mentioned above, turbidity removal by membrane filtration has many advantages that conventional sedimentation and sand filtration methods do not have. Therefore, it is becoming increasingly popular in water purification and sewage treatment as an alternative or supplementary technology to conventional methods.

[0006] Usually, the hollow fiber membrane module is connected to a pipeline through which the filtrate, which is the filtration target liquid, passes. In order to achieve the processing capacity required by the water treatment system, several filter modules are connected in series, and further, several rows of filter modules are connected in parallel. The filter modules of the water treatment system are arranged in a rack, and the ends of each filter module are connected to the pipes laid on the rack through joints.

[0007] The disadvantage of the known system is that the water treatment system requires a very large space and requires a plurality of components such as connecting parts associated with the connecting pipes and supporting members for supporting the weight. In addition, the construction of the water treatment device cannot start until the building for arranging the water treatment device at the water treatment site is completed, and a long time is required before the water treatment device is completed, which is a problem.

[0008] As a membrane module water treatment device, a water treatment device in which a special header or the like is prepared in the membrane module and the header is connected has been proposed. For example, Patent Document 1 discloses a water treatment system including a train composed of filter modules. Prior art literature Patent Literature

[0009] Patent Document 1: European Patent No. 1743690 Summary of the invention Problems to be Solved by the Invention

[0010] In the water treatment system described in Patent Document 1, each row of filter components is connected up and down by a horizontal liquid collecting pipe for filtrate and concentrate. Each filter component has a branch pipe for filtrate at the top, and these branch pipes are laid between adjacent components of adjacent rows. These branch pipes between the rows composed of filter components are connected to the filtrate collecting pipe shared by two adjacent rows and laid in parallel with these pipes above two adjacent upper liquid collecting pipes. Due to such a design, the distance between the rows is required for the connecting branch pipes between the rows.

[0011] In addition, the construction of the water treatment system takes a lot of time and a large area. There are also many parts, and sometimes a construction error can cause fatal defects.

[0012] In view of the above problems, an object of the present invention is to propose a water treatment device that has fewer components than conventional devices, can reduce the time required for installation, and can achieve space saving. Means for solving problems

[0013] The present inventors have conducted intensive studies to solve the above problems and have found that the above problems can be solved by selecting an appropriate hollow fiber membrane module and constructing a piping system with a weight and structure that can withstand transportation, thereby completing the present invention.

[0014] That is, the present invention is as follows. <<Method 1>> A water treatment device, the water treatment device comprising one or more units consisting of the following: a hollow fiber membrane module group, the hollow fiber membrane module group consisting of more than 3 and less than 10 hollow fiber membrane modules including a hollow fiber membrane bundle consisting of a plurality of hollow fiber membranes; a piping group, the piping group comprising a raw water delivery piping connected to each of the hollow fiber membrane modules via a raw water inlet connecting the outside of the hollow fiber membrane module with the space outside the hollow fiber membrane, a filtered water collection piping connected via a filtrate discharge outlet connecting the outside of the hollow fiber membrane module with the space inside the hollow fiber membrane, and a discharged water recovery piping connected via a cleaning discharge outlet connecting the outside of the hollow fiber membrane module with the space outside the hollow fiber membrane; and a supporting member group, the supporting member group consisting of supporting members for supporting the hollow fiber membrane module, the raw water delivery piping, the filtered water collection piping, and the discharged water recovery piping, The mass per unit membrane area of ​​the hollow fiber membrane is 1.0 kg / m 2 the following. <<Method 2>> The water treatment device according to embodiment 1, wherein the total membrane area per unit area of ​​the water treatment device is 1,000 m 2 / m 2 above. <<Method 3>> The water treatment device according to aspect 1 or 2, wherein the water treatment devices of one unit are configured to be connected to each other, and a maximum of five units can be connected. <<Method 4>> The water treatment device according to any one of aspects 1 to 3, wherein the hollow fiber membrane module group and the pipe group are connected via a flexible joint. <<Method 5>> The water treatment device according to any one of aspects 1 to 4, wherein the pipe group, the casing of the hollow fiber membrane module, and the support member are made of a material having a specific gravity of 1.3 g / cm 3 Made of the following resins. <<Method 6>> The water treatment device according to any one of Modes 1 to 5, wherein the hollow fiber membrane module comprises: The hollow fiber membrane bundle is composed of a plurality of hollow fiber membranes; a housing housing the hollow fiber membrane bundle; and A bonding and fixing part, wherein the bonding and fixing part is used to bond and fix the two ends of the hollow fiber membrane bundle to the shell, in, The hollow fiber membrane is a microfiltration (MF) membrane or an ultrafiltration (UF) membrane, The bonding and fixing portion comprises: A first bonding and fixing layer, wherein the first bonding and fixing layer is provided at one end of the hollow fiber membrane and uses a resin material to bond and fix the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the housing; and a second bonding and fixing layer, the second bonding and fixing layer being at the other end of the hollow fiber membrane and bonding and fixing the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the shell with a resin material; The hollow fiber membrane module satisfies all of the following conditions (A), (B) and (C): (A) the filling rate of the hollow fiber membranes, expressed as 100×(total cross-sectional area of ​​the hollow fiber membranes) / (internal cross-sectional area of ​​the housing), is 42% or less; (B) the outer diameter of the hollow fiber membrane is 1.3 mm or less; and (C) The total membrane area of ​​the hollow fiber membrane is 50m 2 above. <<Method 7>> The water treatment device according to any one of aspects 1 to 6, wherein the effective length of the hollow fiber membrane is 1.6 m or more. <<Method 8>> A water treatment device according to any one of methods 1 to 7, wherein the filtered water collecting pipe is located below the discharged water recovery pipe, the filtered water collecting pipe is surrounded by the discharged water recovery pipe and its connecting joint, and the opening portion that can be connected to the filtered water collecting pipe is less than 30 cm. <<Method 9>> A water treatment device, comprising: a hollow fiber membrane module group, the hollow fiber membrane module group being composed of a plurality of hollow fiber membrane modules including a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes; and A piping group includes a raw water delivery pipe, a filtered water collection pipe, and a discharged water recovery pipe respectively connected to each of the hollow fiber membrane modules. <<Method 10>> According to the water treatment device of aspect 9, the water treatment device further includes: a supporting member that supports the hollow fiber membrane module, the filtered water collecting pipe, and the discharged water recovery pipe. <<Method 11>> The water treatment device according to aspect 9 or 10, wherein the raw water conveying pipe, the filtered water collecting pipe, and the discharged water recovery pipe are laid along a laying direction of the plurality of hollow fiber membrane modules. <<Method 12>> The water treatment device according to aspect 9 or 10, wherein the support member integrally fixes the hollow fiber membrane module, the filtered water collecting pipe, and the discharged water recovery pipe. <<Method 13>> A water treatment device according to any one of methods 9 to 12, wherein the filtered water collecting pipe and the discharged water recovery pipe are located above the hollow fiber membrane module, and the discharged water recovery pipe and the filtered water collecting pipe are laid in sequence starting from the top of the water treatment device. <<Method 14>> A filtering method, comprising filtering a filtrate using the water treatment device described in any one of methods 1 to 13. The filtering method comprises: A filtering step of filtering the filtrate through the hollow fiber membrane by external pressure filtration to obtain a filtrate; a cleaning process performed after the filtering process; and The chemical cleaning step is performed after the filtering step and the cleaning step are repeated multiple times. in, The cleaning process comprises: Combining: backwashing in which the filtrate is passed from the inside to the outside of the hollow fiber membrane, or flushing in which the filtrate is introduced from the raw water inlet and discharged from the washing outlet; and The filtrate containing bubbles is introduced from the raw water inlet and discharged from the cleaning outlet, and the air washing of the hollow fiber membrane is performed by shaking the hollow fiber membrane with the bubbles. Backwashing-air washing or flushing-air washing to clean the outer surface of the hollow fiber membrane; and, The drug cleaning process includes: A chemical cleaning step of filling the hollow fiber membrane module with a chemical solution, introducing the chemical solution from the raw water inlet and discharging the chemical solution from the filtrate outlet and / or the cleaning outlet to circulate the chemical solution; a drug liquid discharging step of discharging the drug liquid from the hollow fiber membrane module after the drug liquid washing step; a rinsing step of rinsing the inside of the hollow fiber membrane module with filtered water or water after the chemical solution discharging step; and After the rinsing step, a rinsing liquid discharge step of discharging the filtered water or the water after rinsing is performed. <<Method 15>> A filtering method according to aspect 14, wherein in the cleaning step, backwashing or flushing is performed before the backwash-air washing simultaneous cleaning or flushing-air washing simultaneous cleaning. <<Method 16>> The filtration method according to aspect 14 or 15, further comprising: after the cleaning step, a discharge step of discharging cleaning drainage from the outside and the hollow portion of the hollow fiber membrane from the raw water inlet or the cleaning drainage port. <<Method 17>> The filtration method according to aspect 16, wherein the discharge step introduces compressed air into the interior of the hollow fiber membrane module from the raw water inlet or the cleaning outlet to discharge the cleaning drainage. <<Method 18>> The filtration method according to any one of aspects 14 to 17, wherein the chemical liquid discharge step is to introduce compressed air from the raw water inlet or the cleaning outlet into the interior of the hollow fiber membrane module to discharge the cleaning drainage liquid. <<Method 19>> The filtration method according to aspect 18, wherein the chemical solution discharge step and / or the rinse solution discharge step is to discharge the chemical solution, the filtered water or the water by introducing compressed air into the raw water inlet or the cleaning outlet. <<Method 20>> The filtration method according to any one of aspects 9 to 19, wherein the volume per unit membrane area of ​​the chemical solution and the rinse solution is 1.0 L / m 2 the following. <<Method 21>> A leak repair method, characterized in that the leak repair method comprises: a bubble inspection step of introducing compressed air from the filtered water collection pipe in the water treatment device of any one of methods 1 to 13 to each hollow fiber membrane module to inspect whether bubbles are generated from the hollow fiber membrane; In the case where the bubbles are detected, a step of identifying the hollow fiber membrane generating the bubbles by exposing the end surface of the hollow fiber membrane bundle on the filtrate collecting pipe side without removing the hollow fiber membrane module in which the bubbles are detected from the water treatment device; and A repairing step is performed on the determined hollow fiber membrane. Effects of the Invention

[0015] According to the present invention, the number of components is reduced compared with the related art, and the time required for installation can be reduced, thereby achieving space saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram showing an example of the water treatment device of the present invention. Figure 2 This is a schematic cross-sectional view showing an example of the structure of a hollow fiber membrane module constituting the water treatment device of the present invention. Figure 3 This is a diagram showing an example of a water treatment system using the water treatment device of the present invention. DETAILED DESCRIPTION

[0017] Hereinafter, a preferred embodiment of the present invention (hereinafter also referred to as the present embodiment) will be described in detail. It should be noted that the present invention is not limited to the present embodiment.

[0018] [Water treatment equipment] Figure 1 An example of a water treatment device according to this embodiment is shown. Figure 1 As shown, the water treatment device 1 includes one or more units consisting of the following: a hollow fiber membrane module group 110, the hollow fiber membrane module group consisting of more than 3 and less than 10 ( Figure 1 5 in the example) comprising a hollow fiber membrane module 100 including a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes; a piping group 120 including three main pipes, namely a raw water delivery pipe 121 connected to the hollow fiber membrane module 100 via a raw water inlet (not shown) of the hollow fiber membrane module 100, a filtrate collection pipe 122 connected via a filtrate outlet (not shown), and a discharge water recovery pipe 123 connected via a cleaning outlet (not shown); and a supporting member group 130 including supporting members 131 and 132 for supporting the hollow fiber membrane module group 110 and the piping group 120.

[0019] <<Hollow Fiber Membrane Module>> The water treatment device 1 of this embodiment includes: a hollow fiber membrane module group 110 composed of 3 or more and 10 or less hollow fiber membrane modules 100. If there are 3 or more and 10 or less hollow fiber membrane modules 100, they can be assembled in advance at a processing factory, then transported to a water treatment site, and assembled as a water treatment device at the water treatment site, thereby reducing the time required for setting up the water treatment device 1.

[0020] Figure 2 This is a schematic cross-sectional view showing an example of the structure of a hollow fiber membrane module constituting the water treatment device 1 of the present invention. Figure 2The hollow fiber membrane module 100 shown is a hollow fiber membrane module 100 including a hollow fiber membrane bundle 10 composed of a plurality of hollow fiber membranes 11, a shell 30 accommodating the hollow fiber membrane bundle 10, and a bonding and fixing portion 20 for bonding and fixing both ends of the hollow fiber membrane bundle 10 to the shell 30. The hollow fiber membrane module 100 has a raw water inlet 54 connecting the outside of the hollow fiber membrane module 100 with the space 42 outside the hollow fiber membrane 11, a filtrate outlet 52 connecting the outside of the hollow fiber membrane module 100 with the space 41 inside the hollow fiber membrane 11, and a cleaning outlet 53 connecting the outside of the hollow fiber membrane module 100 with the space 42 outside the hollow fiber membrane 11.

[0021] <Hollow fiber membrane bundle> The hollow fiber membrane bundle 10 in the hollow fiber membrane module 100 is composed of a plurality of hollow fiber membranes 11 and is housed in a housing 30 for use. The number of hollow fiber membranes 11 in the hollow fiber membrane bundle 10 is preferably appropriately set so as to satisfy a predetermined filling rate when housed in the housing 30. The number of hollow fiber membranes 11 in the hollow fiber membrane bundle 10 is, for example, 1,000 or more and 100,000 or less, or 2,000 or more and 50,000 or less, 3,000 or more and 40,000 or less, or 5,000 or more and 30,000 or less.

[0022] -Hollow fiber membrane- The hollow fiber membrane 11 in the hollow fiber membrane module 100 is a microfiltration (MF) membrane or an ultrafiltration (UF) membrane. Therefore, the average pore size of the hollow fiber membrane 11 is 1 nm (0.001 μm) or more and 10 μm or less, preferably 10 nm (0.01 μm) or more and 700 nm (0.7 μm) or less, and more preferably 20 nm (0.02 μm) or more and 600 nm (0.6 μm) or less. When the average pore size is 1 nm (0.001 μm) or more and 10 μm or less, the separation performance is sufficient and the connectivity of the pores can be ensured. The average pore size of the hollow fiber membrane 11 can be measured by the mean flow pore size measurement method specified in ASTM: F316-86 (also known as a semi-dry method).

[0023] The surface opening rate of the hollow fiber membrane 11 is preferably 25% or more and 60% or less, more preferably 25% or more and 50% or less, and further preferably 25% or more and 45% or less. The surface opening rate is the surface opening rate of the side of the hollow fiber membrane 11 that contacts the filtered liquid (raw water) (preferably the outer side of the hollow fiber membrane 11). In the hollow fiber membrane 11, if the surface opening rate of the side in contact with the filtered liquid is 25% or more, the clogging of the membrane and the deterioration of the water permeability due to the surface of the membrane being rubbed can be suppressed, thereby improving the filtration stability. On the other hand, if the surface opening rate of the side in contact with the filtered liquid is 60% or less, the required separation performance can be exerted.

[0024] The surface opening ratio of the hollow fiber membrane 11 can be obtained from an electron microscope photograph of the outer surface of the hollow fiber membrane 11. Specifically, the area of ​​each part can be obtained by performing black-and-white binary processing on the electron microscope photograph of the surface of the hollow fiber membrane 11 for the hole part and the non-hole part of the surface opening, and substituting the obtained area of ​​each part into the following mathematical formula to obtain the surface opening ratio of the hollow fiber membrane 11. Opening ratio [%] = 100 × (hole area) / {(hole area) + (non-hole area)}

[0025] The magnification of the electron microscope photograph used in the calculation of the surface opening ratio is preferably increased to such an extent that the shapes of the holes opened on the outer surface of the hollow fiber membrane 11 can be clearly identified. On the other hand, from the viewpoint of increasing the viewing area as much as possible and knowing the averaged surface opening ratio as much as possible, an excessively large magnification is not suitable. From these viewpoints, the magnification of the electron microscope photograph can be set, for example, as follows based on the cumulative median diameter of the pores opening on the outer surface of the hollow fiber membrane 11 (the pore diameter corresponding to 50% of the cumulative area value): When the cumulative median diameter is about 1 to 10 μm, the magnification is 1000 to 5000 times When the cumulative median diameter is about 0.1 to 1 μm, 5000 to 20000 times When the cumulative median diameter is around 0.03 to 0.1 μm, it is 10,000 to 50,000 times. The black-and-white binarization process can also be performed using an electron microscope photograph or a copy thereof with a commercially available image analysis system.

[0026] The porosity of the hollow fiber membrane 11 is preferably 50% to 80%, more preferably 55% to 65%. When the porosity is 50% or more, water permeability is high, while when the porosity is 80% or less, mechanical strength can be improved.

[0027] The inner diameter of the hollow fiber membrane 11 is preferably 0.10% to 1.00 mm, more preferably 0.30% to 0.80 mm. The outer diameter of the hollow fiber membrane 11 is preferably 1.30 mm, more preferably 0.3% to 1.3 mm, further preferably 0.5 mm to 1.00 mm.

[0028] The hollow fiber membrane 11 preferably has a thickness of 80 μm to 1000 μm, more preferably 100 μm to 300 μm. If the membrane thickness is 80 μm or more, the membrane strength can be ensured, while if it is 1000 μm or less, the pressure loss due to the membrane resistance can be suppressed.

[0029] (Raw materials of hollow fiber membrane) The hollow fiber membrane 11 in the hollow fiber membrane module 100 is preferably composed of a porous membrane made of synthetic resin. The resin constituting the hollow fiber membrane 11 in the present embodiment is preferably a thermoplastic resin, and more preferably a polyolefin resin or a fluorine-based polyolefin resin.

[0030] Examples of the polyolefin include polyethylene, polypropylene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and mixtures thereof. Examples of the fluorine-based polyolefin resin include polyvinylidene fluoride resin (PVDF), chlorotrifluoroethylene resin, tetrafluoroethylene resin, ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-monochlorotrifluoroethylene copolymer (ECTFE), ethylene-chlorotrifluoroethylene copolymer, polyvinylidene fluoride (which may also contain a hexafluoropropylene domain) and hexafluoropropylene resin, and substances selected from the group consisting of mixtures of these resins.

[0031] Since these resins are excellent in operability and toughness, they are excellent as raw materials for hollow fiber membrane 11. Among them, a homopolymer selected from the group consisting of vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, ethylene, tetrafluoroethylene and trichlorofluoroethylene, or a copolymer selected from two or more of the above groups, or a mixture of the above homopolymer and the above copolymer, is preferred due to its excellent mechanical strength, chemical strength (chemical resistance) and good formability. More specifically, fluororesins such as polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, and ethylene-chlorotrifluoroethylene copolymer are preferred.

[0032] In addition, the thermoplastic resin constituting the hollow fiber membrane 11 in this embodiment preferably has a three-dimensional network structure rather than a spherulite structure. By constituting the hollow fiber membrane 11 with a thermoplastic resin having a three-dimensional network structure, the connectivity of the pores from the inner surface to the outer surface of the hollow fiber membrane 11 can be improved.

[0033] (Physical properties of hollow fiber membranes) The initial value of the tensile elongation at break of the hollow fiber membrane 11 is preferably 60% or more, more preferably 80% or more, further preferably 100% or more, and particularly preferably 120% or more. The compressive strength of the hollow fiber membrane 11 is preferably 0.2 MPa or more, more preferably 0.3 MPa or more and 1.0 MPa or less, and further preferably 0.4 MPa or more and 1.0 MPa or less.

[0034] (Method for producing hollow fiber membrane) The hollow fiber membrane 11 in the present embodiment can be produced by a known method or a method to which a person skilled in the art has appropriately modified the known method. The hollow fiber membrane 11 in the present embodiment can be produced, for example, by extrusion molding of a melt-kneaded product containing a thermoplastic resin as a raw material.

[0035] <Housing> The shell 30 in the hollow fiber membrane module 100 is a container for accommodating the hollow fiber membrane bundle 10. The shell 30 and the hollow fiber membrane bundle 10 are fixed by the adhesive fixing part 20 described later. After the hollow fiber membrane module 100 is formed, the inside of the module 100 is divided into an outer space 42 of the hollow fiber membrane 11 and an inner space 41 of the hollow fiber membrane 11, and these spaces 41 and 42 have a structure connected with the hollow fiber membrane 11 in between.

[0036] The shell 30 in this embodiment has a raw water inlet 54, a filtrate outlet 52, and a cleaning outlet 53. After the shell 30 and the hollow fiber membrane bundle 10 are fixed by the adhesive fixing part 20 described later, these raw water inlet 54, filtrate outlet 52, and cleaning outlet 53 serve as the raw water inlet 54, filtrate outlet 52, and cleaning outlet 53 of the hollow fiber membrane module 100, and have the following functions respectively. Raw water inlet 54: has the function of connecting the outside of the module 100 and the outer space 42 of the hollow fiber membrane 11 Filtrate outlet 52: has the function of connecting the outside of the module 100 and the inner space 41 of the hollow fiber membrane 11 Cleaning outlet 53: has the function of connecting the outside of the module 100 and the outer space 42 of the hollow fiber membrane 11

[0037] The housing 30 may include a first cylindrical member 31 for housing the hollow fiber membrane bundle 10 and a second cylindrical member 32 for arranging the adhesive fixing portion 20. The second cylindrical member 32 is preferably arranged at both ends of the first cylindrical member 31.

[0038] The second cylindrical member 32 may have the above-mentioned raw water inlet 54, filtrate outlet 52, and cleaning outlet 53. In addition, the second cylindrical member 32 is preferably composed of a second cylindrical member 32a and a second cylindrical member 32b, wherein the second cylindrical member 32a is arranged on the side of the hollow fiber membrane module 100 where the filtrate is taken out, and has the filtrate outlet 52 and the cleaning outlet 53; the second cylindrical member 32b is arranged on the side of the hollow fiber membrane module 100 where the filtrate is introduced, and has the raw water inlet 54.

[0039] The inner diameter of the first cylindrical member 31 of the housing 30 is preferably 170 mm or more, more preferably 190 mm or more; and preferably 250 mm or less, more preferably 230 mm or less. The outer diameter of the first cylindrical member 31 can be, for example, 170 mm or more and 300 mm or less. The length of the first cylindrical member 31 can be appropriately set according to the required effective length of the hollow fiber membrane 11, for example, 1.0 m or more and 3.0 m or less, preferably 1.5 m or more and 2.0 m or less. The inner diameter of the second cylindrical member 32 of the housing 30 can be greater than the inner diameter of the first cylindrical member 31, preferably more than 180 mm, more preferably more than 200 mm; and preferably less than 280 mm, more preferably less than 250 mm. The outer diameter of the second cylindrical member 32 can be, for example, more than 180 mm and less than 330 mm. The length of the second cylindrical member 32 can be appropriately set, for example, it can be more than 0.2 m and less than 1.0 m. It should be noted that the second cylindrical member 32 must be composed of two members (the second cylindrical member 32a and the second cylindrical member 32b) as a group.

[0040] The material of the housing 30 is preferably set from the viewpoints of moldability, cost, mechanical durability, chemical durability, and specific gravity. The housing 30 is preferably made of a material having a specific gravity of 1.3 g / cm 3 The housing 30 is preferably made of the above-mentioned lightweight resin selected from, for example, ABS, nylon, PE, PP, PPE, and the like.

[0041] It is preferable that the housing 30 further includes a fairing cylinder 50 as an optional member inside the second cylindrical member 32 . It should be noted that in Figure 2 In the figure, the distance between the first adhesive fixing layer 21 and the second adhesive fixing layer 22 which defines the effective length of the hollow fiber membrane 11 is represented by the symbol "L".

[0042] <Fixation of hollow fiber membrane bundle and shell> In the hollow fiber membrane module 100 , the hollow fiber membrane bundle 10 and the housing 30 are fixed by the adhesive fixing part 20 .

[0043] <Adhesive fixing part> The bonding and fixing part 20 in the hollow fiber membrane assembly 100 has the function of bonding and fixing the two ends of the hollow fiber membrane bundle 10 to the shell 30. The bonding and fixing part 20 has: a first bonding and fixing layer 21, which is used to bond and fix the hollow fiber membranes 11 to each other and the hollow fiber membrane bundle 10 to the inner wall of the shell 30 at one end of the hollow fiber membrane 11 with a resin material; and a second bonding and fixing layer 22, which is used to bond and fix the hollow fiber membranes 11 to each other and the hollow fiber membrane bundle 10 to the inner wall of the shell 30 at the other end of the hollow fiber membrane 11 with a resin material.

[0044] The first adhesive fixing layer 21 and the second adhesive fixing layer 22 constituting the adhesive fixing portion 20 are made of a resin material. Examples of the resin material include polyurethane resin, epoxy resin, acrylic resin, and silicone resin.

[0045] (Necessary conditions for hollow fiber membrane modules) The hollow fiber membrane module 100 preferably satisfies all of the following conditions (A), (B) and (C), namely (A) the filling rate of the hollow fiber membrane is 42% or less, preferably 38% or less; (B) the outer diameter of the hollow fiber membrane is 1.3 mm or less, preferably 1.1 mm or less; and (C) The total membrane area of ​​the hollow fiber membrane is 50 m 2 Above, preferably 70m 2 The hollow fiber membrane module 100 described above.

[0046] In the above, the "filling rate of the hollow fiber membrane" is calculated based on "100×(total cross-sectional area of ​​the hollow fiber membrane) / (internal cross-sectional area of ​​the shell)". In addition, when the shell 30 is composed of a first cylindrical member 31 and a second cylindrical member 32, the "internal cross-sectional area of ​​the shell" refers to the cross-sectional area of ​​the inner side of the first cylindrical member 31 that accommodates the hollow fiber membrane bundle 10.

[0047] The hollow fiber membrane module 100 in this embodiment is preferably composed of a relatively thin hollow fiber membrane 11 having an outer diameter of 1.3 mm or less. Thus, even if the filling rate of the hollow fiber membrane 11 is reduced to 42%, the membrane area of ​​the hollow fiber membrane 11 can be increased. In addition, by reducing the filling rate of the hollow fiber membrane 11 to 42% or less, it is advantageous in terms of improving the discharge of turbid matter and ensuring a large membrane area.

[0048] From the viewpoint of turbidity discharge performance, the filling rate of the hollow fiber membrane is 42% or less, preferably 38% or less, and preferably 30% or more, more preferably 35% or more.

[0049] From the viewpoint of filtration efficiency, the effective length L of the hollow fiber membrane 11 is preferably 1.5 m or more, more preferably 1.6 m or more, further preferably 1.7 m or more, and particularly preferably 1.8 m or more. The "effective length L of the hollow fiber membrane" refers to the length of the hollow fiber membrane 11 that contributes to filtration, such as Figure 2 As shown, it means the average value of the length of the hollow fiber membrane 11 exposed between the first adhesive fixing layer 21 and the second adhesive fixing layer 22.

[0050] The total membrane area of ​​the hollow fiber membrane 11 is 50 m 2 Above, preferably 70m 2 More than 80m 2 The hollow fiber membrane module 100 in this embodiment has a total membrane area of ​​50 m 2 The “total membrane area of ​​the hollow fiber membranes” refers to the total membrane area of ​​the hollow fiber membranes 11 that contribute to filtration, and refers to the total outer area of ​​the portion of the hollow fiber membranes 11 exposed between the first adhesive fixing layer 21 and the second adhesive fixing layer 22 .

[0051] <<Piping Group>> The piping group 120 is composed of three main pipes, namely a raw water delivery pipe 121, a filtered water collection pipe 122, and a discharged water recovery pipe 123, which are respectively connected to the raw water inlet 54, the filtrate outlet 52, and the cleaning outlet 53 of the hollow fiber membrane module 100. The thickness of each main pipe is not particularly limited, but it is preferably designed within the range where the linear velocity of the water flowing through the main pipe does not exceed 3m / s. The flow rate of water flowing through the main pipe is calculated based on the filtration capacity of the hollow fiber membrane module 100 to be installed, and the linear velocity is calculated accordingly. For example, the diameter of the main pipe is preferably in the range of 100 mm to 250 mm, and more preferably 120 mm to 200 mm. In addition, the length of each main pipe is not particularly limited, but is preferably 2000 mm or less.

[0052] A branch pipe for connecting the hollow fiber membrane assembly 100 to the main pipe is connected to the main pipe. The diameter of the branch pipe is preferably designed within the range where the linear velocity of the flowing water does not exceed 3m / s. For example, it is preferably 40A or more and 80A or less, and more preferably 50A or more and 65A or less. The method for connecting the branch pipe to the main pipe is not particularly limited, and there are methods such as welding with a welding rod and bonding with an adhesive, but the method of melting and connecting the main pipe and the branch pipe is strong in strength and stable in size, so it is preferred. In addition, the length of each branch pipe is not particularly limited, but considering the ease of operation of the joint, it is preferably 100mm or more and 200mm or less.

[0053] The pipe group 120 preferably uses a specific gravity of 1.3 g / cm 3 The following resins are used to make the pipes 121 to 123 of the pipe group 120. In addition, the material of the pipes 121 to 123 is preferably set from the viewpoints of moldability, cost, mechanical durability, chemical durability, and specific gravity. The pipes 121 to 123 are preferably made of a material selected from ABS, nylon, PE, PP, PPE, etc. Among them, PE and PP are particularly good in cost, durability, and moldability, and are therefore preferred.

[0054] like Figure 1 As shown, it is preferred to lay a raw water delivery pipe 121, a filtered water collection pipe 122, and a discharged water recovery pipe 123 along the laying direction of the plurality of hollow fiber membrane modules 100 (ie, the direction in which the hollow fiber membrane modules are arranged).

[0055] <<Supporting member group>> The support member group 130 is composed of a support member 131 that directly supports the hollow fiber membrane module 100 and the raw water delivery pipe 121, and a support member 132 that directly supports the filtered water collection pipe 122 and the discharged water recovery pipe 123. The support members 131 and 132 need to have strength to bear the weight of the hollow fiber membrane module 100 and the pipes 121 to 123 containing water, but need to be designed to achieve a balance between firmness and overall weight in consideration of assembly performance and overall weight.

[0056] Although not limited to the following examples, the support member group 130 may, for example, have the following structure. That is, the support member 131 for carrying the hollow fiber membrane module 100 is arranged at the lower part of the hollow fiber membrane module 100 while fixing the raw water delivery pipe 121 connected to the raw water inlet 54. The support member 131 is composed of two support members 131a and 131b having semicircular openings, and the raw water delivery pipe 121 can be fixed by, for example, clamping the raw water delivery pipe 121 from the top and bottom by these two support members 131a and 131b. According to this fixing method, the support member 131 for supporting the hollow fiber membrane module 100 is fixed to the raw water delivery pipe 121, and further, the nut N (refer to Figure 1 and Figure 2 ) is placed on the supporting member 131, and the raw water inlet 54 and the raw water delivery pipe 121 are connected by a connecting joint 124 such as a flexible joint.

[0057] Secondly, considering that the connection joint 124 becomes shorter, it is preferable to arrange the filtered water collection pipe 122 and the discharged water recovery pipe 123 above the hollow fiber membrane module 100. The filtered water collection pipe 122 and the discharged water recovery pipe 123 can be fixed by the same method as the raw water delivery pipe 121, using, for example, a support member 132 composed of three support members 132a, 132b, and 132c. That is, first, the support member 132a having a semicircular opening is placed on the nut N on the filtered water side with the opening facing upward (see Figure 1 and Figure 2 ) and place the filtered water collecting pipe 122 on the semicircular opening. Next, the filtered water collecting pipe 122 is clamped by a supporting member 132b having two semicircular openings in the up and down directions, and the drain water recovery pipe 123 is placed on the other semicircular opening of the supporting member 132b, and then the supporting member 132c is placed thereon and the drain water recovery pipe is clamped. Then, the filtrate discharge port 52 and the cleaning discharge port 53 can be connected to the filtered water collecting pipe 122 and the drain water recovery pipe 123 respectively by using a connecting joint 124 such as a flexible joint, so that the pipe group 120 and the hollow fiber membrane module 110 become one. In this way, the supporting member 132 can fix the hollow fiber membrane module 100, the filtered water collecting pipe 122, and the drain water recovery pipe 123 as a whole. Furthermore, the supporting member 132 can integrally fix the hollow fiber membrane module 100 , the raw water transport pipe 121 , the filtered water collecting pipe 122 , and the discharged water recovery pipe 123 .

[0058] In this configuration, the raw water delivery pipe 121, the hollow fiber membrane module 100, the filtered water collection pipe 122, and the drain water recovery pipe 123 can be assembled in order from bottom to top, and the respective pipes can be connected to the hollow fiber membrane module 100 using the connection joint 124. In this way, the filtered water collection pipe 122 can be surrounded by the support member group 130, the drain water recovery pipe (lateral pipe) 123, and the connection joint (longitudinal pipe) 124 connecting the drain water recovery pipe 123 and the hollow fiber membrane module 100, thereby protecting it from falling objects and collapsed objects. At this time, the size of the opening portion (the gap between the pipe group 120 and the support member group 130) that can be connected to the filtered water collection pipe 122 is preferably 30 cm or less. Here, the "size of the opening portion" means the length of the longest part of the opening portion when viewed from the direction in which the opening portion appears to be the widest (largest) (for example, the front direction (the direction perpendicular to the direction in which the hollow fiber membrane module 100 is arranged)). The opening may be rectangular, in which case the "size of the opening" is the length of the long side of the rectangle. If the opening is not rectangular, the "size of the opening" is the length of the long side of the rectangle of the maximum area that the opening can contain.

[0059] The supporting members 131 and 132 constituting the supporting member group 130 are preferably made of resin by injection molding. In addition, the material of the supporting members 131 and 132 is preferably set from the viewpoints of moldability, cost, mechanical durability, chemical durability, etc. and specific gravity. The supporting members 131 and 132 are preferably made of a material with a specific gravity of 1.3 g / cm 3 The supporting members 131 and 132 are preferably made of a material selected from ABS, nylon, PE, PP, PPE, etc., and more preferably made of a material reinforced with glass fiber. ABS, nylon, and PP with glass fiber are excellent in cost, durability, and formability, and are therefore particularly preferred. The glass fiber content is preferably 20% to 40%, and more preferably 30% to 40%. In addition, among glass fibers, long fibers are better entangled with each other than short fibers, and are more likely to generate strength, and are therefore preferred.

[0060] <<Connection Joint>> When the shell 30, piping group 120, and supporting member group 130 of the hollow fiber membrane module 100 are made by injection molding using resin, there are some dimensional deviations. Here, by setting the connection joint 124 that connects the above-mentioned components to each other or the components and the piping as a flexible joint, it is possible to absorb their dimensional deviations, thereby well connecting the above-mentioned components to each other or the components and the piping. In addition, by setting the connection joint 124 as a flexible joint, even if there is vibration during transportation, it can be absorbed, and the water treatment device 1 can be prevented from being damaged during transportation. Furthermore, in the case of connecting multiple water treatment devices 1 of one unit, by setting the connection joint 124 as a flexible joint, some dimensional deviations between the water treatment devices 1 of one unit can be absorbed.

[0061] As the flexible joint, it is not limited to the following, in addition to the method of connecting one connection port and the other connection port with a flexible tube such as rubber, and fixing the tube from the outside with a rigid material so that the tube does not fall off, expansion joints or rubber anti-vibration joints can also be mentioned. For example, it is preferable to use a Victam joint manufactured by Victam Co., Ltd., a pipe joint fastened with a cap nut manufactured by Maezawa Chemical Co., Ltd., a pipe joint fastened with a bolt, etc.

[0062] Furthermore, by making a portion of the filtered water collection pipe 122 or the discharged water recovery pipe 123 transparent, after confirming the presence of bubbles during the compressed air leakage inspection of the hollow fiber membrane module 100, the leakage detection becomes easy. Figure 1 As shown, a connection joint 124 for connecting the drain water recovery pipe 123 and the cleaning drain port 53 of the hollow fiber membrane module 100 with a partially transparent flexible joint 124 a may be considered.

[0063] The material of the flexible joint is preferably selected from the viewpoints of moldability, cost, mechanical durability, chemical durability, etc. The flexible joint is preferably made of a material selected from, for example, ABS, nylon, PE, PP, PPE, PVC, etc. The above-mentioned transparent flexible joint 124a can be realized by selecting transparent ABS or transparent PVC as a transparent material to make a part of the flexible joint. For example, a transparent expansion joint of a pipe joint fastened with a cap nut can be used.

[0064] In the present invention, the mass per unit area of ​​the hollow fiber membrane 11 of the water treatment device 1 having the above-mentioned structure is set to 1.0 kg / m 2 As a result, the area of ​​the hollow fiber membrane 11 that can be transported at one time becomes larger, and the transportation becomes more efficient.

[0065] In the present invention, it is preferred that the total membrane area of ​​the hollow fiber membrane 11 per unit area of ​​the water treatment device 1, that is, the footprint, is 1000 m 2 / m 2 As a result, the membrane area that can be transported at one time becomes larger, and transportation becomes more efficient.

[0066] Furthermore, it is preferred that the hollow fiber membrane assembly group 110, the piping group 120, and the supporting member group 130 are interconnected as a unit, and a maximum of five units can be connected. Thus, it is possible to suppress the situation where the linear velocity of the liquid flowing in the piping becomes too large and causes an increase in the piping pressure loss. For example, in the case where 5 hollow fiber membrane assemblies 100 are provided in one unit, by setting the connected units to less than five units (i.e., a total of 25 hollow fiber membrane assemblies), the linear velocity of the liquid in the piping can be set to less than 3m / s, thereby suppressing the increase in the piping pressure loss.

[0067] <<Operation method of water treatment device>> Figure 3 1 shows a flow chart of an example of a filtration system for performing a filtration step and a cleaning step, and preferably a discharge step, and further a chemical cleaning step using the water treatment device 1 of the present embodiment.

[0068] Figure 3 The filtration system 1000 shown has a structure in which the water treatment device 1 of the present invention, the filtered liquid tank 200, the coarse filter 210, the filtrate tank 300, and the compressor 400 are connected by pipes with valves appropriately arranged. Figure 3 In the figure, the pump for delivering liquid, the drainage pipes usually installed in each tank, the liquid tank and the accompanying pipes for liquid cleaning, and the sensors for checking the operating status are omitted.

[0069] use Figure 3The filtration system 1000 can perform the filtration method of the present invention including a predetermined filtration step and a cleaning step, for example, as follows.

[0070] <<Filtration process (F)>> In the filtration step, the filtrate is filtered through the hollow fiber membranes in the hollow fiber membrane module 100 in the water treatment device 1 to obtain a filtrate. exist Figure 3 In the filtration system 1000, after the raw liquid such as suspended water and process liquid is temporarily stored in a raw liquid tank (not shown), the filtrate after coarse filtration by the coarse filter 210 is used as the filtrate in the filtration method of the present invention. The filtrate is stored in the filtrate tank 200. The filtrate in the filtrate tank 200 is introduced into the water treatment device 1 from the raw water inlet 54 via the filtrate feed valve V1 , filtered from the outside of the hollow fiber membrane through the thick wall portion of the hollow fiber membrane, and stored in the filtrate tank 300 .

[0071] <<Cleaning process>> The washing process includes simultaneous backwashing-air washing (ASBW) or simultaneous flushing-air washing (ASFL) which is performed by combining backwashing (BW) or flushing (FL) with air washing (AS). BW or FL can be performed before ASBW or ASFL, or FL can be performed after ASBW or ASFL. Furthermore, a discharge step may be performed after the cleaning step. In use Figure 3 In the case of the filtration system 1000, BW, FL and AS, and ASBW and ASFL, and the discharge process can be performed as follows.

[0072] In this specification, backwashing is sometimes referred to as "BW", flushing is referred to as "FL", air washing is referred to as "AS", backwashing and air washing performed simultaneously (backwash-air washing simultaneous cleaning) is referred to as "ASBW", and flushing and air washing performed simultaneously (flushing-air washing simultaneous cleaning) is referred to as "ASFL".

[0073] <Backwash (BW)> In BW, the filtrate is passed from the inside to the outside of the hollow fiber membrane in the hollow fiber membrane module. In this case, the filtrate in the filtrate tank 300 is introduced into the water treatment device 1 from the filtrate outlet 52 via the backwash valve V3, and leaches from the inner side of the hollow membrane through the thick wall portion of the hollow fiber membrane to the outer space of the hollow fiber membrane. In this process, the suspended matter accumulated in the pores of the thick wall portion of the hollow fiber membrane is squeezed out to the outer side of the hollow fiber membrane, thereby cleaning the hollow fiber membrane. The filtrate leached into the outer space of the hollow fiber membrane is discharged to the outside of the system through the washing discharge port 53 and the washing waste discharge valve V5.

[0074] <Flushing (FL)> In FL, the filtrate is passed to the outside of the hollow fiber membranes to wash away the suspended matter adhering to the outer surface of the hollow fiber membranes. In FL, the filtrate in the filtrate tank 200 is introduced into the water treatment device 1 from the raw water inlet 54 via the filtrate feed valve V1, passes through the outer space of the hollow fiber membrane, and is discharged to the outside of the system via the cleaning outlet 53 and the cleaning drain valve V5.

[0075] <Air Scrubber (AS)> In AS, compressed air is introduced from the air inlet 51 and discharged from the cleaning outlet 53, and the hollow fiber membrane is shaken by the air (bubbles) passing through the outside of the hollow fiber membrane. In AS, air compressed by the compressor 400 is introduced into the water treatment device 1 from the air inlet 51 via the AS valve V6, passes through the outer space of the hollow fiber membrane, and is discharged to the outside of the system via the cleaning outlet 53 and the cleaning waste liquid discharge valve V5.

[0076] <Backwash-Air Scrubber Simultaneous Cleaning (ASBW)> In ASBW, the above-mentioned BW and AS are performed simultaneously. That is, the filtrate in the filtrate tank 300 is introduced into the hollow fiber membrane module 100 in the water treatment device 1 from the filtrate discharge port 52 via the backwash valve V3, and is discharged to the outside of the system via the cleaning discharge port 53 and the cleaning drain discharge valve V5. At the same time, the compressed air of the compressor 400 is introduced into the water treatment device 1 from the air inlet 51 via the AS valve V6, and is discharged to the outside of the system via the cleaning discharge port 53 and the cleaning drain discharge valve V5.

[0077] <Simultaneous flushing-air scrubbing (ASFL)> In ASFL, the above-mentioned FL and AS are performed simultaneously. That is, after the treated liquid in the filtered liquid tank 200 is introduced into the hollow fiber membrane module 100 in the water treatment device 1 from the raw water inlet 54 via the filtered liquid delivery valve V1, it is discharged to the outside of the system via the cleaning outlet 53 and the cleaning drain valve V5. At the same time, the compressed air of the compressor 400 is introduced into the water treatment device 1 from the air inlet 51 via the AS valve V6, and is discharged to the outside of the system via the cleaning outlet 53 and the cleaning drain valve V5.

[0078] <Discharging process> In the discharge step, the cleaning waste liquid remaining in the hollow fiber membrane module 100 is discharged. The discharge process can be carried out by discharging the compressed air introduced from the cleaning discharge port 53 of the hollow fiber membrane module 100 in the water treatment device 1 through the compressed air valve V7 for the discharge process, the drug return valve V8, and the bypass valve V9 together with the cleaning drainage liquid remaining inside the hollow fiber membrane module 100 to the outside of the system through the raw water inlet 54 and the cleaning drainage valve V4.

[0079] [Filtering method] The filtering method of the present invention is a filtering method for filtering a filtrate using the water treatment device 1 of the present invention described above. The aforementioned filtering methods include: A filtration step of filtering the filtrate through the hollow fiber membrane 11 by external pressure filtration to obtain a filtrate; a washing step performed after the filtration step; and After repeating the above-mentioned filtering process and cleaning process for many times, the chemical cleaning process is performed. in, The aforementioned cleaning process includes: Combination of: backwashing in which the filtrate is passed from the inside to the outside of the hollow fiber membrane 11 or flushing in which the filtrate is introduced from the raw water inlet 54 and discharged from the washing outlet 13; and Air washing by introducing a filtrate containing bubbles from the raw water inlet 54 and discharging it from the cleaning outlet 53, and shaking the hollow fiber membrane 11 with the bubbles; and Performing backwashing-air washing or flushing-air washing to clean the outer surface of the hollow fiber membrane 11; and, The aforementioned drug cleaning process includes: A chemical cleaning step of filling the hollow fiber membrane module 100 with a chemical solution, introducing the chemical solution from the raw water inlet 54 and discharging the chemical solution from the filtrate outlet 52 and / or the cleaning outlet 53 to circulate the chemical solution; a liquid discharge step of discharging the liquid medicine from the hollow fiber membrane module 100 after the liquid medicine washing step; a rinsing step of rinsing the inside of the hollow fiber membrane module 100 with filtered water or water after the liquid medicine discharge step; and After the rinsing step, a rinsing liquid discharge step of discharging the filtered water or the water after rinsing is performed.

[0080] <Filtration process> The filtration process in the filtration method of the present embodiment is external pressure filtration. That is, it is a filtration process in which a filtrate containing a filtrate is supplied to the outer surface of the hollow fiber membrane 11, the filtrate is passed through the membrane thickness (thick wall) portion of the hollow fiber membrane 11, and the liquid seeping from the inner surface of the hollow fiber membrane 11 is taken out as a filtrate. In the hollow fiber membrane assembly 100 of the present embodiment, the method of introducing the filtrate from the lower side of the assembly 100 for external pressure filtration is more likely to discharge turbid matter, so it is preferred. It should be noted that in this specification, "filtrate" means a substance contained in the treated water supplied to the hollow fiber membrane 11 in the filtration process, which should be removed by filtration and separated from the filtrate.

[0081] The filtrate in the filtration step is not particularly limited, but is typically water containing suspended matter that can be removed by the filtration step, and examples thereof include suspended water and process liquid. In this specification, the term "suspended water" refers to natural water, domestic drainage (wastewater), their treated water, etc. As natural water, river water, lake water, groundwater, and seawater can be cited as examples. Treated water that has been subjected to sedimentation treatment, sand filtration treatment, coagulation sedimentation sand filtration treatment, ozone treatment, activated carbon treatment, etc. on these natural waters is also included in the "suspended water" in this specification. A typical example of domestic drainage is sewage. Primary sewage treatment water that has been subjected to screening, sedimentation treatment, etc., secondary sewage treatment water that has been subjected to biological treatment, and tertiary treatment (highly treated) water that has been subjected to coagulation sedimentation sand filtration, activated carbon treatment, ozone treatment, etc. are also included in the "suspended water" in this specification. These suspended waters may also contain turbidity (humus colloids, organic colloids, clay, bacteria, etc.) composed of microscopic organic and inorganic substances at or below the μm level, and one or more of organic-inorganic mixtures, high-molecular substances from bacteria / algae, etc.

[0082] The quality of suspended water can be specified by turbidity and / or organic matter concentration. Both turbidity and organic matter concentration are evaluated using average values ​​rather than instantaneous values. Based on the turbidity according to JIS K0101 (Kaolin Turbidity Standard), suspended water is classified into low turbidity water with a turbidity of less than 1, medium turbidity water with a turbidity of 1 or more and less than 10, high turbidity water with a turbidity of 10 or more and less than 50, and ultra-high turbidity water with a turbidity of 50 or more. In addition, the above turbidity: 1 degree = 0.7 NTU (Nephelometric Turbidity Unit). Based on the organic matter concentration (Total Organic Carbon (TOC) concentration: mg / L), suspended water is divided into low TOC water less than 1, medium TOC water greater than or equal to 1 and less than 4, high TOC water greater than or equal to 4 and less than 8, and ultra-high TOC water greater than 8. Generally speaking, water with higher turbidity and / or TOC is more likely to clog a porous filtration membrane. Therefore, it is preferred that the average turbidity of the filtrate supplied to the filtration step in this embodiment is 10 degrees or more because the performance of the hollow fiber membrane module 100 can be appropriately exerted.

[0083] Process liquid refers to the liquid to be separated (i.e., the mixed liquid before separation) when separating valuable substances from non-valuable substances in the fields of food, pharmaceuticals, semiconductor manufacturing, etc. The suspended water, process liquid, etc. as described above, which have been coarsely filtered by an appropriate coarse filter 210 or the like, may be used as the filtrate in the present invention.

[0084] The filtration process in this embodiment is carried out, for example, by introducing the filtered liquid from the raw water inlet 54 of the hollow fiber membrane module 100 into the outer space 42 of the hollow fiber membrane 11, and the filtrate that has passed through the thick wall portion of the hollow fiber membrane 11 seeps out from the inner surface of the hollow fiber membrane 11, and the filtrate in the inner space 41 of the hollow fiber membrane 11 is taken out from the filtrate discharge port 52 of the hollow fiber membrane module 100.

[0085] The flow rate of the filtrate is per 1m 2 The permeation flow rate (LMH or L / [m 2 ·h]), it is preferably 10LMH or more and 500LMH or less, more preferably 50LMH or more and 200LMH or less, and further preferably 75LMH or more and 150LMH or less.

[0086] <Cleaning process> The cleaning step in the filtering method of the present invention comprises: Combination of backwashing (BW) in which the filtrate is passed from the inside to the outside of the hollow fiber membrane 11 or flushing (FL) in which the filtrate is introduced from the raw water inlet 54 and discharged from the washing outlet 53; and Air washing (AS) in which a filtrate containing bubbles is introduced from the raw water inlet 54 and discharged from the cleaning outlet 53 to shake the hollow fiber membrane 11 with bubbles; and Backwashing-air washing (ASBW) or flushing-air washing (ASFL) is performed to clean the outer surface of the hollow fiber membrane 11 . Here, the air for AS can be introduced by providing a connection joint 124 for introducing air to a branch pipe provided in the raw water transport pipe 121 .

[0087] According to the filtration method of this embodiment, the filtration step and the washing step can be repeated, and the hollow fiber membrane module 100 can be operated for a long time and the filtration treatment can be continued. The timing of stopping the filtration process and starting the cleaning process can be appropriately set. For example, the filtration process can be stopped and the cleaning process can be started when a predetermined time has passed after the filtration process is started or restarted. Alternatively, the filtration process can be stopped and the cleaning process can be started when the water permeability of the filtration process reaches a predetermined value. In this case, it is preferred to start the cleaning process when the water permeability of the filtration flux divided by the filtration pressure decreases to 70% of the initial value, and more preferably when it decreases to 50%. The method of managing the start of the cleaning process based on time has the advantage of being able to always keep the hollow fiber membrane 11 clean because regular membrane cleaning is ensured. The method of managing the start of the cleaning process based on water permeability has the advantage of being able to perform efficient cleaning.

[0088] In the cleaning step of this embodiment, Backwashing (BW) or flushing (FL) can be performed before ASBW or ASFL. A flush (FL) can also be performed after ASBW or ASFL. In the cleaning process of this embodiment, it is preferable to perform ASBW or ASFL after performing BW or FL alone, because it is possible to more effectively discharge turbid matter brought into the hollow fiber membrane module 100. In addition, if BW or FL is performed before ASBW or ASFL, since suspended matter attached to the outer surface of the hollow fiber membrane 11 is peeled off and the close contact of the hollow fiber membrane bundle 10 is relaxed, it is possible to suppress the deterioration of the hollow fiber membrane 11 caused by the friction caused by the subsequent ASBW or ASFL.

[0089] - Backwash (BW) - Backwashing (BW) is a cleaning method that allows filtrate to pass into the inner side of the hollow fiber membrane 11. By BW, suspended matter accumulated in the pores of the thick wall portion of the hollow fiber membrane 11 can be squeezed out of the hollow fiber membrane 11. The flow rate of the filtrate during BW is preferably 0.5 to 3 times, and more preferably 0.7 to 3 times, the permeation flow rate X of the filtration step as a permeation flow rate. When BW is performed before ASBW or ASFL, the implementation time is, for example, 10 times or more and 120 seconds or less, preferably 15 seconds or more and 60 seconds or less.

[0090] - Flushing (FL) - Flushing (FL) is a cleaning method in which the filtrate is introduced from the raw water inlet 54 and discharged from the cleaning outlet 53 to allow the filtrate to pass to the outside of the hollow fiber membrane 11. The suspended matter attached to the outer surface of the hollow fiber membrane 11 can be washed away by the FL. The flow rate of the filtrate in the FL is preferably 50 LMH or more and 150 LMH or less, and more preferably 60 LMH or more and 100 LMH or less. When FL is performed before ASBW or ASFL, the implementation time is, for example, 10 seconds to 120 seconds, preferably 15 seconds to 60 seconds. When FL is performed after ASBW or ASFL, the implementation time is, for example, 10 seconds to 120 seconds, preferably 15 seconds to 60 seconds.

[0091] - Air Scrubber (AS) - Air washing (AS) is a cleaning method in which compressed air is introduced from the air inlet 51 and discharged from the cleaning outlet 53 while the hollow fiber membrane module 100 is filled with water, thereby shaking the hollow fiber membrane 11 with air (bubbles). At AS, the amount of the introduced compressed air is 1m2 relative to the cross-sectional area of ​​the casing 30 of the hollow fiber membrane module 100. 2 , preferably 170Nm 3 / h and above and 400Nm 3 / h or less, more preferably 200Nm 3 / h and above and 350Nm 3 / h or less, more preferably 200Nm 3 / h and above and 300Nm 3 / h or less.

[0092] - Backwash-Air Scrubber Simultaneous Cleaning (ASBW) - In ASBW, the above-mentioned backwashing (BW) and air scrubbing (AS) are performed simultaneously. The implementation time of ASBW is, for example, 10 seconds to 120 seconds, preferably 15 seconds to 60 seconds.

[0093] - Simultaneous flushing and air washing (ASFL) - In ASFL, the above-mentioned flushing (FL) and air scrubbing (AS) are carried out simultaneously. The implementation time of ASFL is, for example, 10 seconds to 120 seconds, preferably 15 seconds to 60 seconds.

[0094] <Discharging process> In the filtering method of the embodiment, after the cleaning process, a discharge process may be performed to discharge the cleaning drainage remaining inside the hollow fiber membrane module 100, specifically, the outside and hollow part of the hollow fiber membrane 11, from the raw water inlet 54 or the cleaning outlet 53. This is preferred. By performing the discharge process after the cleaning process, the suspended matter in the hollow fiber membrane module 100 can be discharged more effectively.

[0095] The discharge step can be performed, for example, by allowing the water to flow naturally downward due to gravity and be discharged from the raw water inlet 54 of the hollow fiber membrane module 100 , or by forcibly introducing compressed air into the hollow fiber membrane module 100 from the cleaning outlet 53 .

[0096] After the discharge step, the weight of the hollow fiber membrane module 100 is preferably 1.70 times or less, more preferably 1.60 times or less, and further preferably 1.55 times or less, the initial dry weight of the hollow fiber membrane module 100 .

[0097] <Chemical cleaning process> The drug cleaning step in the filtering method of the present invention comprises: A chemical cleaning step of filling the hollow fiber membrane module 100 with a chemical solution, introducing the chemical solution from the raw water inlet 54 and discharging the chemical solution from the filtrate outlet 52 and / or the cleaning outlet 53 to circulate the chemical solution; a liquid discharge step of discharging the liquid medicine from the hollow fiber membrane module 100 after the liquid medicine washing step; a rinsing step of rinsing the inside of the hollow fiber membrane module 100 with filtered water or water after the liquid medicine discharge step; and After the rinsing step, a rinsing liquid discharge step of discharging the filtered water or the water after rinsing is performed.

[0098] In the filtering method of this embodiment, after a series of filtering steps are repeatedly implemented, chemical cleaning is performed at a frequency of several times a day to several times a year. The chemicals used are preferably chlorine-based oxidants such as sodium hypochlorite, oxygen-based oxidants such as hydrogen peroxide, alkalis such as sodium hydroxide, inorganic acids such as hydrochloric acid, organic acids such as citric acid, reducing agents such as sodium sulfite, etc., but are not limited thereto.

[0099] For example, it is possible to first use a mixed liquid of 0.5% sodium hypochlorite and 1% sodium hydroxide to perform immersion cleaning for about 8 hours to clean organic pollutants, and then use a 1% citric acid aqueous solution to perform immersion cleaning for about 8 hours to clean inorganic pollutants. After that, the inside of the hollow fiber membrane module 100 is rinsed with raw water, filtered water, and water to make it neutral, and then the filtration process is restarted.

[0100] Here, the liquid medicines such as sodium hypochlorite, sodium hydroxide, citric acid used in cleaning cannot be discharged directly, and are generally disposed of as sewage or industrial waste after being harmlessly treated by neutralization or reduction operations. At this time, if a water treatment device with a small installation area and a large membrane area is used as in the present embodiment, since the dead zone of the pipe is small, not only the amount of liquid medicine used is small, but also the amount of liquid medicine used for neutralization or reduction can be reduced.

[0101] In the chemical solution discharge step, it is preferred that the cleaning drain liquid naturally flows down due to gravity, or compressed air is introduced into the hollow fiber membrane module 100 from the cleaning drain port 53 to forcibly discharge the cleaning drain liquid from the raw water inlet 54 .

[0102] In the chemical solution discharge step and / or the rinse solution discharge step, it is preferred that the cleaning waste liquid naturally flows down due to gravity, or compressed air is introduced into the cleaning discharge port 53 to forcibly discharge the cleaning waste liquid from the raw water inlet 54 .

[0103] Preferably, the volume per unit membrane area of ​​the above-mentioned chemical solution and rinse solution is 1.0 L / m 2 More preferably, it is 0.8 L / m 2 If the volume per unit membrane area is 1.0L / m 2 The following can reduce the amount of cleaning liquid and waste liquid to be treated.

[0104] [Leak repair method] The leakage repair method according to the present invention includes: a bubble inspection process of introducing compressed air from the filtered water collecting pipe in the water treatment device according to the present invention to each hollow fiber membrane assembly to check whether bubbles are generated from the hollow fiber membrane; a determination process of exposing the end face of the filtered water collecting pipe side of the hollow fiber membrane bundle to determine the hollow fiber membrane that has generated bubbles without removing the hollow fiber membrane assembly where the bubbles are detected from the water treatment device when bubbles are detected; and a repair process of repairing the determined hollow fiber membrane.

[0105] <Bubble Inspection Process> In the bubble inspection process, compressed air is introduced from the filtered water collection pipe 122 in the water treatment device 1 to each hollow fiber membrane module 100 through the valve V7, and the presence or absence of bubbles generated from the hollow fiber membrane is inspected. If the hollow fiber membrane 11 is broken, bubbles can be detected from the transparent pipe connected to the cleaning outlet 53.

[0106] <Confirmation of process> When bubbles are detected, the hollow fiber membrane assembly 100 in which the bubbles are detected is not removed from the water treatment device 1 but the end face on the filtrate discharge port 52 side of the hollow fiber membrane bundle 10 is exposed, and pressurized air is delivered to the hollow fiber membrane assembly 100 via V6. If there is a broken hollow fiber membrane 11, bubbles are generated, thereby identifying the broken hollow fiber membrane 11.

[0107] <Repair process> In the repairing process, the identified hollow fiber membrane is repaired. Specifically, the hollow portion of the identified hollow fiber membrane at the upper end of the assembly is plugged with a nail or the like to be sealed. Thus, the leaking hollow fiber membrane assembly 100 can be repaired without removing it from the water treatment device 1. Example

[0108] Hereinafter, the present invention will be described in more detail by way of examples. Evaluations in the following Examples and Comparative Examples were performed by the following methods.

[0109] (Example 1) <<Piping Group>> Five holes with a diameter of 42 mm were opened in a row with a center-to-center distance of 320 mm on a polyethylene pipe with an inner diameter of 148 mm and an outer diameter of 168 mm (the distance from the end surface of the main pipe to the center of the nozzle was 160 mm on both sides), and a polyethylene nozzle with an inner diameter of 42 mm and an outer diameter of 60 mm was welded in each hole so that the height from the bottom surface of the main pipe was 106 mm. Three main pipes with nozzles were prepared as the raw water delivery pipe 121, the filtered water collection pipe 122, and the discharged water recovery pipe 123. All the nozzles were grooved in accordance with the construction instructions of VICTAULIC Co., Ltd. so as to fit with the 50A VICTAULIC joint made by VICTAULIC Co., Ltd. In addition, both ends of all the main pipes were grooved in accordance with the construction instructions of VICTAULIC Co., Ltd. so as to fit with the 150A VICTAULIC joint. In addition, five sets of pipes were prepared to connect the later-described drain port 53 of the hollow fiber membrane module 100 for cleaning to the drain water recovery pipe 123. A 50A super-clear expansion joint manufactured by Maezawa Chemicals Co., Ltd. was used in the connection pipe between the drain port and the drain water recovery pipe 123.

[0110] <<Supporting member group>> As Figure 1 The supporting members 131b and 132a shown in the figure are provided with a semicircle with a diameter of 168mm on the wide side of a rectangular parallelepiped with a length of 254mm, a width of 260mm and a height of 36mm. In addition, as the supporting member 132b, a semicircle with a diameter of 168mm is provided on both wide sides of a rectangular parallelepiped with a length of 232.5mm, a width of 260mm and a height of 36mm. Furthermore, as the supporting members 131a and 132c, a semicircle with a diameter of 168mm is provided on the wide side of a rectangular parallelepiped with a length of 123.5mm, a width of 260mm and a height of 36mm. The above-mentioned supporting members 131a, 131b, 132a, 132b and 132c are all manufactured by injection molding using polypropylene to which long-fiber glass fibers are added. Glue reduction and ribs are provided as required. A total of 10 supporting members 131b and 132a, 5 supporting members 132b, and a total of 10 supporting members 131a and 132c were prepared.

[0111] <<Hollow fiber membrane module group>> 16,500 PVDF (polyvinylidene fluoride) hollow fiber membranes 11 (manufactured by Asahi Kasei Corporation) were bundled in a length of 2.3 m, suspended vertically, the lower end faces were cut to align the faces, and the hollow portion was sealed. The hollow fiber membrane bundle 10 formed in this way was inserted into a housing 30, which had a first cylindrical member (tube inner diameter 204 mm) 31 for accommodating the hollow fiber membrane bundle 10, and a second cylindrical member (tube inner diameter 204 mm) 32 with a rectifier tube 50 of an inner diameter of 196 mm installed inside. It should be noted that the hollow fiber membrane 11 used here has an average pore diameter of 0.1 μm, an inner diameter of 0.6 mm, and an outer diameter of 0.95 mm.

[0112] Next, 40 columnar members (diameter 11 mm) were inserted into the end portion (first adhesive fixing layer 21 ) of the hollow fiber membrane bundle 10 on the first cylindrical member 31 side at positions where through holes were to be formed.

[0113] Next, while the bonding and fixing portion forming container with the potting material introduction tube installed is fixed to both ends of the housing 30, the potting material is injected into the first cylindrical member 31 and the second cylindrical member 32 of the housing 30 while rotating. As the potting material, a two-component thermosetting polyurethane resin (SANYU REC (Strain): SA-6330A2 / SA-6330B5 (trade name)) is used. When the potting material undergoes a curing reaction and stops fluidization, the centrifuge is stopped, the housing 30 is taken out, and heated to 50°C in an oven to cure the polyurethane resin.

[0114] Then, the membrane bundle end on the second cylindrical member 32 side of the housing 30 is cut off to open the hollow portion of the hollow fiber membrane 11 on one side sealed in the stage before bonding. On the other hand, the columnar member is removed from the first adhesive fixing layer 21 on the first cylindrical member 31 side to form a plurality of through holes. It should be noted that the membrane effective length of the present hollow fiber membrane module 100 is 2.0 m.

[0115] The filling rate of the manufactured hollow fiber membrane module 100 was 37.2%.

[0116] Conical caps having 50A VICTAULIC joint grooves are fastened and fixed to both ends of the hollow fiber membrane module 100 with nuts N.

[0117] <<Assembly>> The water treatment device 1 is assembled in the following order. 1. Arrange 10 supporting members 131a in a row on a horizontal ground in such a way that the semicircular part becomes the vertical upper side, and fix them to the ground with anchor bolts or the like. Here, the supporting member 131a can be fixed to a metal frame, and the metal frame is fixed to the ground. Here, the supporting member 131a is fixed at a position opposite to each other with a distance of 90 mm from both sides with the installation position of the hollow fiber membrane module 100 as the center. 2. The raw water transport pipe 121 is placed on the semicircular portion of the support member 131 a. 3. The support member 131b is placed on the support member 131a so that the semicircular portion thereof fits into the raw water transport pipe 121. Here, the support members 131a and 131b may be fixed by adhesive, clamps, bolts or the like. 4. Five hollow fiber membrane modules 100 are placed on each of the two support members 131 b / 131 a so that the raw water inlet 54 is located vertically downward and all the outlets are oriented at 90 degrees to the axial direction of the raw water transport pipe 121 . 5. The raw water inlet 54 of all hollow fiber membrane modules 100 and the nozzle of the raw water delivery pipe 121 are fixed via a 50A VICTAULIC joint. A 10A joint is provided on the nozzle of the raw water delivery pipe 121, and an air inlet for AS is provided. 6. For each hollow fiber membrane module, one support member 132 a is placed on the nut N of the filtrate discharge port 52 in the same orientation as the support member 131 b of the raw water transport pipe 121 with the semicircular opening facing upward. 7. The filtered water collecting pipe 122 is placed on the semicircular opening of the supporting member 132a with the nozzle facing vertically downward. 8. The filtrate outlets 52 of all hollow fiber membrane modules 100 are connected to the filtrate collection pipe 122 using a 50A VICTAULIC joint. 9. The support member 132b is placed on the support member 132a so as to sandwich the filtered water collecting pipe 122. Here, the support member a and the support member b may be fixed by adhesive, clamps, bolts, etc. 10. The drain water recovery pipe 123 is placed so that the nozzle of the drain water recovery pipe 123 and the drain port 53 for cleaning of the hollow fiber membrane module 100 face in the same direction. 11. The support member 132c is placed on the support member 132b so as to sandwich the drain water recovery pipe 123. Here, the support member 132b and the support member 132c may be fixed by adhesive, clamps, bolts or the like. 12. An L-shaped pipe is connected downwardly to the nozzle of the discharge water recovery pipe 123, and an L-shaped pipe is also connected upwardly to the cleaning discharge port 53 of the hollow fiber membrane module 100, and these two L-shaped pipes are connected to each other into a "concave"-shaped pipe using a transparent expansion joint. In this way, a unit of the water treatment device 1 is assembled.

[0118] For a water treatment device 1 manufactured in this way, the installation area is 0.42m 2 , membrane area is 495m 2 The unit footprint of the hollow fiber membrane 11 is 1179 m 2 / m 2 Furthermore, by selecting polyethylene and polypropylene as the piping material and using lightweight materials such as ABS as the shell 30 of the hollow fiber membrane module 100, the weight is about 400 kg. Therefore, the weight per unit area of ​​the hollow fiber membrane 11 is 0.8 kg / m 2 Furthermore, the amount of chemical and neutralization / rinsing wastewater during chemical cleaning is 0.75 L / m 2 , which can reduce workload and environmental load.

[0119] The above steps can be assembled at a factory dedicated to assembling water treatment equipment, and can be transported directly to the installation site. In addition, the assembly can be carried out smoothly at the installation site, and there is no risk of pipe damage, etc., which can greatly shorten the construction period compared to the construction of normal water treatment equipment. In the water treatment device 1 of the present embodiment, it is preferable to arrange the hollow fiber membrane modules back to back in a group of five, because this further limits the access to the filtered water collecting pipe 122 . Furthermore, by connecting the raw water delivery pipe 121, the filtered water collection pipe 122, and the discharged water recovery pipe 123 to the water treatment device 1 of each unit using a 150A VICTAULIC joint, two or three units can be connected in series to improve the water treatment capacity.

[0120] Next, the two units Figure 1 The water treatment devices shown (5 hollow fiber membrane modules×2 units) were arranged in parallel, and valve units and pumps were connected to conduct a long-term operation test of the water treatment system obtained above.

[0121] The test was investigated by running the following settings. Operation sequence: F (28.5 minutes), ASBW (1 minute), and FL (0.5 minutes) Set the turbidity of the filtered liquid: 10NTU Filter FLUX: 100LMH Backwash FLUX: 80LMH FL flow: 3m 3 / hr As a result, the system has been operating stably with no water leaks in the pipes for more than a year.

[0122] After one year of operation, as a leak check, the outlet valve of the raw water delivery pipe 121 was closed, and 0.1 MPa compressed air was introduced from the AS pipe of the raw water delivery pipe 121. Bubbles were detected from the transparent expansion joint connected to the drain water recovery pipe 123 of one of the 10 hollow fiber membrane modules 100 installed. Therefore, all water is discharged from the water treatment device 1, the support member 132a for supporting the filtered water collection pipe 122 placed on the hollow fiber membrane module 100 is removed, and the VICTAULIC joint of the filtrate outlet 52 is removed. Furthermore, the nut N and the cover of the hollow fiber membrane module 100 are removed to expose the end face of the filtered water side. Compressed air is introduced again from the pipe for AS, the leaking hollow fiber membrane 11 is identified, and nailing is performed to implement the leak repair. In this way, the leak repair can be completed without removing the hollow fiber membrane module 100 from the water treatment device 1. Industrial Applicability

[0123] The water treatment device of the present invention can be used, for example, in a water purification method including a step of filtering suspended water to obtain a filtrate. In addition, in food manufacturing, for example, when separating liquors such as sake and wine from yeast, the filtration method of the present invention can be used. In the manufacture of pharmaceuticals, for example, when sterilizing when purifying proteins, the filtration method of the present invention can be used. Furthermore, in semiconductor manufacturing, for example, when separating grinding wastewater into abrasives and water, the water treatment device of the present invention can be used. Description of symbols

[0124] 1 Water treatment device 10 Hollow fiber membrane bundle 11 Hollow fiber membrane 20 Bonding and fixing part 21. First bonding and fixing layer 22 Second bonding and fixing layer 30 Shell 31 first cylindrical member 32 second cylindrical member 41 The inner space of the hollow fiber 42 The outer space of the hollow fiber 50 rectifier tube 51 Air inlet 52 Filtrate outlet 53 Drain port for cleaning 54 Raw water inlet 100 Hollow fiber membrane module 110 Hollow fiber membrane module group 120 Pipe group 121 Raw water delivery piping 122 Filter water collection pipe 123 Discharge water recovery piping 124 Connector 130 Supporting member group 131, 131a, 131b, 132, 132a, 132b, 132c support member 200 Filtered liquid tank 210 Coarse filter 300 Filtrate Tank 400 Compressor 1000 Filtration System L is the distance between the first adhesive fixing layer and the second adhesive fixing layer. V1 Filtered liquid delivery valve V3 backwash valve V4 cleaning drain valve V5 cleaning drain valve V6 AS valve V7 Compressed air valve for discharge process V8 Drug Return Valve V9 Bypass Valve

Claims

1. A water treatment device, the water treatment device comprising one or more units consisting of: a hollow fiber membrane module group, the hollow fiber membrane module group consisting of more than 3 and less than 10 hollow fiber membrane modules including a hollow fiber membrane bundle consisting of a plurality of hollow fiber membranes; a piping group, the piping group comprising a raw water delivery piping connected to each of the hollow fiber membrane modules via a raw water inlet connecting the outside of the hollow fiber membrane module with the space outside the hollow fiber membrane, a filtered water collection piping connected via a filtrate discharge outlet connecting the outside of the hollow fiber membrane module with the space inside the hollow fiber membrane, and a discharged water recovery piping connected via a cleaning discharge outlet connecting the outside of the hollow fiber membrane module with the space outside the hollow fiber membrane; and a supporting member group, the supporting member group consisting of a supporting member for supporting the hollow fiber membrane module, the raw water delivery piping, the filtered water collection piping, and the discharged water recovery piping, in, The mass per unit membrane area of ​​the hollow fiber membrane is 1.0 kg / m 2 the following.

2. The water treatment device according to claim 1, wherein: The total membrane area per unit area of ​​the water treatment device is 1,000m 2 / m 2 above.

3. The water treatment device according to claim 1 or 2, wherein: The water treatment devices of the one unit are configured to be connected to each other, and a maximum of five units can be connected.

4. The water treatment device according to any one of claims 1 to 3, wherein: The hollow fiber membrane module group and the pipe group are connected via a flexible joint.

5. The water treatment device according to any one of claims 1 to 4, wherein: The pipe group, the casing of the hollow fiber membrane module, and the supporting member are made of a material having a specific gravity of 1.3 g / cm 3 Made of the following resins.

6. The water treatment device according to any one of claims 1 to 5, wherein: The hollow fiber membrane assembly comprises: The hollow fiber membrane bundle is composed of a plurality of hollow fiber membranes; a housing housing the hollow fiber membrane bundle; and A bonding and fixing part, wherein the bonding and fixing part is used to bond and fix the two ends of the hollow fiber membrane bundle to the shell, in, The hollow fiber membrane is a microfiltration (MF) membrane or an ultrafiltration (UF) membrane, The bonding and fixing portion comprises: A first bonding and fixing layer, wherein the first bonding and fixing layer is provided at one end of the hollow fiber membrane and uses a resin material to bond and fix the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the housing; and a second bonding and fixing layer, the second bonding and fixing layer being at the other end of the hollow fiber membrane and bonding and fixing the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the shell with a resin material; The hollow fiber membrane module satisfies all of the following conditions (A), (B) and (C): (A) the filling rate of the hollow fiber membranes, expressed as 100×(total cross-sectional area of ​​the hollow fiber membranes) / (internal cross-sectional area of ​​the housing), is 42% or less; (B) the outer diameter of the hollow fiber membrane is 1.3 mm or less; and (C) The total membrane area of ​​the hollow fiber membrane is 50m 2 above.

7. The water treatment device according to any one of claims 1 to 6, wherein: The effective length of the hollow fiber membrane is greater than 1.6 m.

8. The water treatment device according to any one of claims 1 to 7, wherein: The filtered water collecting pipe is located below the drain water recovery pipe, and is surrounded by the drain water recovery pipe and its connecting joint. The opening that can be connected to the filtered water collecting pipe is less than 30 cm.

9. A water treatment device, comprising: A hollow fiber membrane module group, wherein the hollow fiber membrane module group is composed of a plurality of hollow fiber membrane modules including a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes; as well as A piping group includes a raw water delivery pipe, a filtered water collection pipe, and a discharged water recovery pipe respectively connected to each of the hollow fiber membrane modules.

10. The water treatment device according to claim 9, further comprising: A supporting member supports the hollow fiber membrane module, the filtered water collecting pipe, and the discharged water recovery pipe.

11. The water treatment device according to claim 9 or 10, wherein: The raw water delivery pipe, the filtered water collection pipe, and the discharged water recovery pipe are laid along the laying direction of the plurality of hollow fiber membrane modules.

12. The water treatment device according to claim 9 or 10, wherein: The supporting member integrally fixes the hollow fiber membrane module, the filtered water collecting pipe, and the discharged water recovery pipe.

13. The water treatment device according to any one of claims 9 to 12, wherein: The filtered water collecting pipe and the discharged water recovery pipe are located above the hollow fiber membrane module, and the discharged water recovery pipe and the filtered water collecting pipe are laid in sequence starting from the top of the water treatment device.

14. A filtration method, comprising filtering a filtrate using the water treatment device according to any one of claims 1 to 13, The filtering method comprises: A filtering step of filtering the filtrate through the hollow fiber membrane by external pressure filtration to obtain a filtrate; A cleaning process performed after the filtering process; as well as The chemical cleaning step is performed after the filtering step and the cleaning step are repeated multiple times. in, The cleaning process comprises: Combining: backwashing in which the filtrate is passed from the inside to the outside of the hollow fiber membrane, or flushing in which the filtrate is introduced from the raw water inlet and discharged from the washing outlet; and The filtrate containing bubbles is introduced from the raw water inlet and discharged from the cleaning outlet, and the air washing of the hollow fiber membrane is performed by shaking the hollow fiber membrane with the bubbles. Backwashing-air washing or flushing-air washing to clean the outer surface of the hollow fiber membrane; and, The drug cleaning process includes: A chemical cleaning step of filling the hollow fiber membrane module with a chemical solution, introducing the chemical solution from the raw water inlet and discharging the chemical solution from the filtrate outlet and / or the cleaning outlet to circulate the chemical solution; a drug liquid discharging step of discharging the drug liquid from the hollow fiber membrane module after the drug liquid washing step; a rinsing step of rinsing the inside of the hollow fiber membrane module with filtered water or water after the chemical solution discharging step; and After the rinsing step, a rinsing liquid discharge step of discharging the filtered water or the water after rinsing is performed.

15. The filtering method according to claim 14, wherein: In the cleaning process, backwashing or flushing is performed before the simultaneous backwashing-air washing or flushing-air washing.

16. The filtering method according to claim 14 or 15, further comprising: After the cleaning step, a discharge step is performed to discharge the cleaning drainage from the outside and the hollow portion of the hollow fiber membrane from the raw water inlet or the cleaning drainage port.

17. The filtering method according to claim 16, wherein: The discharge step introduces compressed air into the hollow fiber membrane module from the raw water inlet or the cleaning outlet to discharge the cleaning waste liquid.

18. The filtering method according to any one of claims 14 to 17, wherein: The chemical liquid discharge step is to introduce compressed air from the raw water inlet or the cleaning outlet into the hollow fiber membrane module to discharge the cleaning drainage liquid.

19. The filtering method according to claim 18, wherein: The chemical liquid discharge step and / or the rinse liquid discharge step is to introduce compressed air into the raw water inlet or the cleaning discharge port to discharge the chemical liquid, the filtered water or the water.

20. The filtering method according to any one of claims 9 to 19, wherein: The volume of the drug solution and rinse solution per unit membrane area is 1.0 L / m 2 the following.

21. A leak repair method, characterized in that: The leakage repair method comprises: a bubble inspection step of introducing compressed air from the filtered water collection pipe in the water treatment device according to any one of claims 1 to 13 to each hollow fiber membrane module to inspect whether bubbles are generated from the hollow fiber membrane; In the case where the bubbles are detected, a step of identifying the hollow fiber membrane generating the bubbles by exposing the end surface of the hollow fiber membrane bundle on the filtrate collecting pipe side without removing the hollow fiber membrane module in which the bubbles are detected from the water treatment device; and A repairing step is performed on the determined hollow fiber membrane.

Images