KR100378292B1 - Hollow fiber membrane module for treating waste water containing highly concentrated suspended solids - Google Patents

Abstract

The present invention relates to a hollow fiber membrane module for treating wastewater containing high concentration suspended solids, comprising: (a) two or more hollow fiber membranes in which bundles of hollow fiber membranes (1) arranged vertically side by side on a plane are fixed by fixing members (2) Unit; (b) an H-shaped union located between the hollow fiber membrane units, comprising a pair of connecting portions 3 and a pair of sealing portions 4, and forming a permeate recovery portion 5; ; And (c) a U-shape located at the end of the hollow fiber membrane unit at both ends of the module, consisting of one connecting portion 3 'and one sealing portion 4', forming a permeate recovery portion 5 '. By using the hollow fiber membrane module according to the present invention including a form union, it is possible to maintain excellent filtration efficiency over a long period of time by minimizing membrane fouling and clogging phenomenon during the treatment of wastewater containing a high concentration of suspended solids.

Description

HOLLOW FIBER MEMBRANE MODULE FOR TREATING WASTE WATER CONTAINING HIGHLY CONCENTRATED SUSPENDED SOLIDS}

The present invention relates to a hollow fiber membrane module for treating wastewater containing a high concentration of suspended solids. Specifically, the hollow fiber membrane bundles are unfolded at regular intervals so that two or more hollow fiber membrane units fixed vertically are arranged so that suspended solids (SS) The present invention relates to a hollow fiber membrane module that can maintain excellent filtration efficiency over a long period of time by minimizing membrane fouling and clogging that may occur when treating wastewater having high concentration of Suspended Solid.

"Hollow fiber membrane module" means the use of a hollow fiber membrane, which is a thin fiber with a myriad of small pores on its surface and a hollow space in the middle, to exclude substances larger than the pore size from multicomponent liquids mixed with various substances, It refers to a device that can effectively recover only a small specific substance through it.

Traditionally, hollow fiber membrane modules have been widely used in the fields of ultrafiltration and precision filtration, such as sterile water, drinking water production, etc., and recently, advanced treatment in sewage terminal treatment, advanced treatment in small scale septic tanks, suspended solids in industrial wastewater. It is actively applied to various fields such as removal, treatment of heavy and high concentration organic wastewater, treatment of industrial water and swimming pool water, as well as recovery of process materials in production processes of food, automobile and steel industries.

In relation to the various uses of the module as described above, the degree of microbial sedimentation when the hollow fiber membrane module is immersed in an aeration tank of a biological wastewater treatment process in which the concentration of suspended solids and microorganisms is maintained at 3000 mg / l or more is related. Because the quality of treated water can be maintained at all times without any waste, the chemicals and maintenance costs required for microbial management are consumed less, and the microorganisms in the aeration tank can be maintained at a high concentration. As the sedimentation tank for separating solid / liquid is not required, it has been found to have significant advantages such as less land area required for installation of the facility. Therefore, research on hollow fiber membrane modules for treating high concentration wastewater has been conducted in Japan, Canada, etc. It was actively performed in some developed countries.

On the other hand, in general, when the hollow fiber membrane module is directly immersed and filtered in wastewater having a high concentration of suspended solids, suspended solids accumulate on the membrane surface or between the membranes of the hollow fiber membrane, resulting in a blockage between the membranes in which the amount of permeate is reduced due to the passage of the membrane. The phenomenon that the filtration life is shortened occurs. Therefore, in order to filter wastewater with a high concentration of suspended solids over a long period of time, the hollow fiber membrane module must have a structure capable of suppressing intermembrane blockage, and aeration or turbulent flow at the bottom of the membrane module. ) Or shake the hollow fiber membrane with ultrasonication or vibration to keep the suspended solids accumulated on the surface or between the membranes.

Various hollow fiber membrane modules have already been proposed using this principle.

US Patent No. 5,922,201 (inventive name: hollow fiber membrane module) by Yamamori et al. Is a hollow fiber membrane EHF270T (pore size of 0.1 µm, porosity of 60% or more, inner diameter of 270) manufactured by Mitsubishi Rayon, Japan from polyethylene Screen Filter Type Hollow Fiber Membrane Module (Total Effective Filtration Membrane), made of 4 pieces of Knitted Fabric (300mm wide, 760mm long) using a micrometer and an outer diameter of 380㎛) and inserted into a 10mm × 300mm housing gap Area of 5 m 2), and in this embodiment, the hollow fiber membrane module was used to perform suction filtration for 9 minutes at a suction pressure of 0.2 kgf / cm 2 in a reactor having a suspended solid concentration of 5,000 mg / l and 1 Repeated experiments with a pause of 1 minute showed that the filtration flow of 1 L / min module could be maintained for 30 days.

However, according to the experimental results of the effective hollow fiber membrane length calculation performed by the present inventors (see reference examples and FIGS. 5 and 6), in the case of the hollow fiber membrane having an inner diameter of 340 µm and an outer diameter of 500 µm, the optimum effective hollow fiber membrane length to which suction pressure is applied is As it is shown to be 10 to 15 cm, the effective length of the hollow fiber membranes of 270 μm and 380 μm used by Yamamori et al. Will be shorter. Therefore, suction pressure does not work evenly on the surface of the hollow fiber membranes. As the phenomenon occurs, the filtration efficiency will be greatly reduced as time passes. In addition, Yamamori et al. Attempted to achieve the purpose by spreading the hollow fiber membranes into a plate-like knitted fabric in which the hollow fiber membranes were knitted in order to suppress the intercalation phenomenon, but overlapping four sheets to increase the filling rate of the hollow fiber membranes per unit area. As a result, when the MLSS concentration increases or the operation period becomes longer, there is a possibility that the operating pressure may increase due to the intermembrane blockage of the hollow fiber membrane in the sheet-like knitted fabric overlapped with four sheets, and the decrease in the amount of permeated water may occur.

Mahendran et al. Disclose a multicomponent liquid in Korean Patent No. 177,263 (name of invention: a skeletal framework consisting of hollow fiber filtration membranes and a method of filtering the substrate to keep the surface of the hollow fiber membranes clean while recovering permeate). Disclosed is a system comprising a gas dispersion device with a skeletal arrangement of hollow fiber filtration membranes for recovering permeate.

However, the hollow fiber membrane disclosed by Mahendran et al. Forms an arch shape (parabolic shape) which is curved upward in the multicomponent liquid, and when the multicomponent liquid contains a large amount of fibrous solids such as hair, the hollow fiber membrane is intertwined. There is a drawback that the intercalation phenomenon may proceed rapidly, and such a module type is not easy to be stacked, so it is not suitable to be applied to a large capacity facility.

In addition, the inventors of the Korean Patent No. 236,921 (name of the invention: immersion type hollow fiber membrane module and wastewater treatment method using the same) and Korean Patent Publication No. 99-45939 (name of the invention: improved hollow fiber membrane module and using the same Wastewater treatment method) In each case, the cylindrical hollow fiber membrane module for supplying air from the central air supply line and the cylindrical hollow fiber membrane module for optimizing the filling form of the hollow fiber membrane and supplying air through the diffuser installed at the bottom were proposed. .

This type of hollow fiber membrane module can exert an excellent function in the direct filtration process of wastewater containing a high concentration of suspended solids, but it is difficult to stack and extend the length of the module has a disadvantage that it is not suitable for large capacity facilities.

Accordingly, the present inventors have conducted a thorough study, as a result of using the hollow fiber membrane module in which the hollow fiber membrane bundles are unfolded at regular intervals and the fixed hollow fiber membrane unit has two or more vertically arranged hollow fiber membrane modules. The present invention has been accomplished by discovering that the intermembrane blockage can be minimized to maintain excellent filtration efficiency over a long period of time.

It is an object of the present invention to provide a hollow fiber membrane module that can maintain excellent filtration efficiency over a long period of time by minimizing membrane contamination and intermembrane blockage when treating wastewater containing suspended solids with a high concentration.

1 is a view showing the structure of a hollow fiber membrane module according to an embodiment of the present invention,

Figure 2 is a side view of the hollow fiber membrane module shown in Figure 1,

3 is a three-dimensional view showing a hollow fiber membrane unit (Unit) used in the hollow fiber membrane module of the present invention,

4A and 4B are longitudinal cross-sectional views of H-shaped unions and U-shaped unions respectively used in the hollow fiber membrane module of the present invention;

5 is a schematic diagram of an apparatus designed for measuring the length of an effective hollow fiber membrane,

6 is a graph showing the change in suction pressure acting on the surface of the hollow fiber membrane according to the length of the hollow fiber membrane, performed in the apparatus of FIG. 5 according to the flux;

7 is a schematic diagram of a wastewater treatment process using a hollow fiber membrane module according to an embodiment of the present invention,

8 is a graph showing the amount of permeated water according to the concentration of MLSS (Mixed Liquor Suspended Solid) of each of the hollow fiber membrane module and the conventional hollow fiber membrane module according to the present invention during wastewater treatment by the wastewater treatment process of FIG.

<Brief Description of Drawings>

1: Hollow Fiber Membrane Module

b: H-type union

c: U-type union

2: Fixing Part

3: Connection Part

4: Potting Part

5: Permeate Collection Part

6: Raw Water

7: Raw Water Storage Tank

8: Transfer Pump

9: Membrane Bioreactor

10: Blower

11: diffuser

12: Treated Water

13: Treated Water Storage Tank

14: Mini Hollow Fiber Membrane Module

15: Vacuum Gauge

16: Peristaltic Pump

In order to achieve the above object, in the present invention, (a) two or more hollow fiber membrane units, in which bundles of hollow fiber membranes 1 arranged vertically side by side on a plane are fixed in a state in which both ends are opened by fixing members 2 (unit); (b) a pair of connecting portions 3 for connecting the ends of the different hollow fiber membrane units in a vertical arrangement, and the pair of connecting portions 3 from the outside of the fixing member 2; H-shaped which consists of a pair of sealing part 4 which seals a hollow fiber membrane, and communicates in a central axis direction between a pair of connection part, and forms the permeate recovery part 5 which communicates with the open end of a hollow fiber membrane. Form union; And (c) one connecting portion 3 'surrounding the ends of the hollow fiber membrane unit at both ends, and the hollow fiber membrane is sealed while joining the connecting portion 3' and the hollow fiber membrane unit at the outside of the fixing member 2; It provides a hollow fiber membrane module comprising a U-shaped union consisting of one sealing portion (4 '), and a permeate recovery portion (5') communicating in the central axis direction and communicating with the open end of the hollow fiber membrane. do.

Hereinafter, the present invention will be described in more detail.

The hollow fiber membrane module according to an embodiment of the present invention shown in FIG. 1 includes (a) three hollow fiber membrane units, (b) two H-shaped unions, and (c) two U-shaped unions in three stages. And a side view thereof is shown in FIG. 2.

(A) The hollow fiber membrane unit according to the present invention consists of a hollow fiber membrane (1) bundle and the fixing member (2). The hollow fiber membrane bundles arranged vertically side by side on the plane are fixed by the fixing member 2 with both ends open, wherein the hollow fiber membrane bundles are arranged at intervals of 0.4 to 0.6 mm so as not to be entangled with each other by aeration air. Preferably, each bundle of hollow fiber membranes consists of 10 to 15 strands of hollow fiber membranes. Figure 3 shows a three-dimensional hollow fiber membrane unit used in the hollow fiber membrane module of the present invention.

The hollow fiber membrane used in the present invention has a material selected from polysulfone, polyacrylonitrile, polymethyl methacrylate, cellulose acetate, and polyolefin, and among them, mechanical strength is required to withstand the aeration strength in order to meet the treatment process. Polyolefin-based polymers with good strength and flexibility are suitable.

In general, however, polyolefin-based polymers are hydrophobic polymers, which are not soaked in water well and do not penetrate water unless high pressure is applied, as well as solute adsorption or pore blocking. Since the permeability is significantly reduced due to the membrane contamination due to the phenomenon, the surface should be modified to be used hydrophilicly.

Surface modification methods include physical and chemical methods. Physical surface modification methods include a method of physically adhering a hydrophilic polymer such as polyvinyl alcohol on a hollow fiber membrane support made of a hydrophobic polymer, and a chemical surface modification method of hollow fiber membrane made of a hydrophobic polymer. And a method of chemically polymerizing a hydrophilic monomer such as acrylamide, acrylic ester, and the like on a support. Representative methods for polymerizing the double polymer include graft polymerization, plasma treatment, electron beam or γ-ray irradiation, UV irradiation, flame treatment and chemical etching. In the present invention, a method of permanently hydrophilizing the hollow fiber membrane is not particularly limited, but the hydrophilic surface modification method of the hollow fiber membrane using plasma is a very thin coating of the hydrophilic polymer on the hydrophobic membrane support to minimize loss of filtration resistance. It is possible to maintain a strong bonding force between the support and the coating layer is preferred as a permanent surface modification method.

Hollow fiber membranes used in the present invention can be prepared by a combination of thermally induced phase separation (TIPS) and stretching (stretching). Since the hollow fiber membrane produced by this combination process can maintain a high porosity (porosity), the filtration resistance is very small.

The hollow fiber membrane according to the present invention thus prepared has a pore size of 0.01 to 0.5 μm, a porosity of 60% or more, a wall thickness of 20 to 200 μm and an outer diameter of 200 to 2,000 μm. In this case, the pore size may be adjusted according to the material to be filtered, the porosity and the wall thickness may be adjusted according to the characteristics of the filtration process, and the outer diameter may be adjusted according to the ratio of the membrane area per unit area in the module manufacturing.

According to the present invention, the length of the hollow fiber membrane may vary depending on the inner diameter and the outer diameter of the hollow fiber membrane, and the adjustment of the length is very important in order to allow the suction pressure induced by the water head difference or the pump to work evenly on the surface of the hollow fiber membrane. That is, by appropriately adjusting the length of the hollow fiber membrane, it is possible to suppress the filtration phenomenon in which only the portion to which suction pressure is applied is filtered and ultimately increase the filtration efficiency of the hollow fiber membrane to increase the washing cycle and thus to maintain the lifetime of the hollow fiber membrane module. . According to the invention, the effective length of the hollow fiber membrane having a wall thickness of 20 to 200 mu m and an outer diameter of 200 to 2,000 mu m is in the range of 0.1 to 2 m, preferably in the range of 0.1 to 0.5 m. For example, the effective length of the hollow fiber membrane having an inner diameter of 340 µm and an outer diameter of 500 µm is 10 to 15 cm.

The fixing member 2 used in the present invention may have a material selected from polycarbonate, polysulfone, acrylic resin and acrylonitrile-butadiene-styrene (ABS) resin, and the fixing liquid may be epoxy resin, polyurethane resin, or the like. Any resin having an adhesive property can be used and is not restricted by physical properties such as viscosity.

According to the present invention (b) the H-shaped union shown in FIG. 4A in its longitudinal section is composed of a pair of connecting portions 3 and a pair of sealing portions 4 and forms a permeate recovery portion 5. It is located between the hollow fiber membrane units.

In the H-shaped union, the pair of connecting portions 3 serves to connect the ends of the different hollow fiber membrane units in vertical vertical arrangement. The stacking in the vertical direction has an effect of fundamentally preventing the intermembrane blockage that may occur when the hollow fiber membrane units are overlapped to increase the filling rate of the hollow fiber membranes. In addition, the pair of seals 4 seals the hollow fiber membranes while engaging the pair of connecting portions 3 from the outside of the fixing member 2, so that the multicomponent liquid (waste water) is not interposed between the hollow fiber membrane pores but the hollow fiber membranes. It serves to prevent passage. The H-shaped union composed of the connecting portion 3 and the sealing portion 4 forms a permeate recovery portion 5 which communicates in the central axis direction between the pair of connecting portions and communicates with the open end of the hollow fiber membrane. This permeate recovery part 5 serves to collect permeate generated by suction pressure induced by water head or pump.

According to the present invention (c) the U-shaped union shown in side view in FIG. 4B is composed of one connecting portion 3 'and one sealing portion 4' and forms a permeate recovery portion 5 '. It is located at the end of the hollow fiber membrane unit at both ends of the module.

In the U-shaped union, the connecting portion 3 'serves to close the end of the hollow fiber membrane unit to close the end, and the sealing portion 4' and the permeate recovery portion 5 'are H-shaped. It has the same position and function as the seal portion 4 and the permeate recovery portion 5 of the union.

The H-shaped union according to the present invention is a type capable of fixing both the upper and lower sides of the hollow fiber membrane unit, the U-shaped union is a streamlined pointed end to minimize the disturbance of the air flow for membrane cleaning, both of them are hollow It has a thickness of 5 to 10 mm so as not to slow down the flow rate of the hollow fiber membrane cleaning air supplied from the bottom of the desert module or prevent the cleaning air from being evenly delivered to the hollow fiber membrane surface.

In addition, polycarbonate, polysulfone, acrylic resin, acrylonitrile-butadiene-styrene (ABS) resin, etc. can be used as the material of these hollow fiber membrane unions, and epoxy resin, unsaturated ester resin, poly Liquid resins such as urethane resins can be used and the viscosity is suitably less than 1,000 centipoise.

According to the present invention, as shown in Figure 7, after immersing the hollow fiber membrane module according to the present invention in the membrane-bioreactor 8 of the biological wastewater treatment process for membrane cleaning from the diffuser 11 located at the bottom of the module The feed water 12 can be obtained from the raw water 6 through the permeate recovery portion of the H-shaped union and the U-shaped union by supplying air and performing suction filtration using a water head difference (for example, 2 m) or a pump.

By using the hollow fiber membrane module erected vertically in the wastewater treatment method of the present invention, it is possible to fundamentally block the intermembrane blockage caused by the fibrous solid material such as hair, and a considerable amount of air required for cleaning the hollow fiber membrane Not only can it be reduced, but the module is installed at a narrow interval of 5 to 10 mm in the membrane-bioreactor, so that no deterioration in filtration performance occurs.

As such, the hollow fiber membrane module according to the present invention has a structure capable of minimizing membrane contamination and intermembrane blockage that may occur when directly filtering wastewater having a high concentration of suspended solids. Not only can it be kept long, but also the water quality of the treated water passed can be used economically and efficiently for the treatment of high concentration waste water.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are not intended to limit the present invention.

Reference Example: Estimation of Effective Hollow Fiber Membrane Length Under Suction Pressure

A membrane area of 0.05 m 2 and a length of 0.5 m, a porosity of 60% or more, a wall thickness of 80 m, and an outer diameter of 500 m, and a permanently hydrophilized polypropylene (PP) hollow fiber membrane (1) Cylindrical small hollow fiber membrane modules 14 of 5, 10, 15 and 20 cm, respectively, were produced. One end of the small hollow fiber membrane module 14 was sealed with epoxy resin and the other end was kept open to collect the filtrate. FIG. 5 is a schematic view showing an experimental apparatus for measuring the length of an effective hollow fiber membrane, wherein a small hollow fiber membrane module 14 having vacuum gauges 15 installed at both ends in a raw water storage tank 7 filled with R / O permeate water is provided. Filtration was performed by immersing and changing the permeate amount to 30, 40 and 55 LH (L / module · hour) using the metering pump 16. The effective hollow fiber membrane length was determined as the effective hollow fiber membrane length by observing the pressure difference between the vacuum gauges provided at both ends of the small hollow fiber membrane.

As a result, the graph which shows the change of the suction pressure which acts on the surface of a hollow fiber membrane with the length of a hollow fiber membrane by the permeate amount is shown in FIG. It can be seen from FIG. 6 that the effective length for the hollow fiber membranes having an inner diameter of 340 µm and an outer diameter of 500 µm is 10 to 15 cm.

Example: High concentration sewage treatment experiment using hollow fiber membrane module according to the present invention

Two 60cm (30cm) units using a hollow fiber membrane (1) made of polypropylene (PP), permanently hydrophilized, with a pore size of 0.5 µm, a porosity of 60% or more, a wall thickness of 80 µm, and an outer diameter of 500 µm. ), Four two-stage hollow fiber membrane modules (total effective filtration membrane area: 2 m 2) were fabricated and mounted on the frame at intervals of 10 mm and applied to the wastewater treatment process shown in FIG. 7. The raw water 6 used sewage generated in a restaurant, and the raw water 6 was stored in the raw water storage tank 7 and the hollow fiber membrane module was immersed at a flow rate of about 10 LPM (L / min) by the transfer pump 8. The membrane-bioreactor 9 was transported relatively constantly. At this time, the water temperature of the reaction tank (9) was maintained at 17 ℃, pH 6 to 8, while supplying 150LPM (l / min) film cleaning air through the acid pipe 11 using the blower 10, The suction pressure induced by the head difference (2 m) was continuously filtered while acting on the surface of the hollow fiber membrane. The filtered treated water 12 was transferred to the treated water storage tank 13, and the permeate amount and water quality were measured every day during the experiment. In addition, the change of permeate amount was observed while the MLSS concentration was artificially changed to 5,000, 10,000 and 15,000 mg / l in order to examine the intercalation phenomenon caused by the microbial concentration of the reactor.

Table 1 shows the detailed operating conditions of the embodiment, and a graph showing the amount of permeated water according to the operating time according to the MLSS concentration is shown in FIG. 8. 8, it can be seen that using the hollow fiber membrane module of the present invention, it is possible to smoothly treat wastewater having high suspended solids without deterioration of filtration efficiency due to membrane contamination or intermembrane blockage. In addition, the average value of analyzing the water quality while driving the above embodiment is shown in Table 2, it can be seen that the COD, BOD and SS is treated more than 98% water quality of the treated water is also very good.

division Condition Air Aeration (LPM; l / min) 150 Operating conditions 5 minutes driving 1 minute stop Head difference (m) 2 Membrane area (㎡) 8 Temperature and pH 17 ° C., 6 to 8

division Before treatment After treatment Average efficiency (%) CODcr (mg / l) 700 15 97.9 BOD (mg / l) 500 3 99.4 SS (mg / l) 50 0.5 99

Comparative Example: High concentration sewage treatment experiment using conventional screen filter type module

Based on the screen filter type module disclosed in U.S. Patent No. 5,922,201 to Yamamori et al., The polypropylene is permanently hydrophilized with a pore size of 0.5 μm, a porosity of at least 60%, a wall thickness of 80 μm, and an outer diameter of 500 μm. Two hollow fiber membrane modules (total effective hollow fiber membrane area: 4 m2), in which four plate-shaped sheets of 76 cm long and 30 cm wide, were laminated using a hollow fiber membrane (PP) made of PP), and the hollow fiber membrane Filtration experiment was performed by applying to the wastewater treatment process shown in FIG. The operating conditions were the same as in the above embodiment.

A graph showing the permeated water amount according to the MLSS concentration according to the operation time is shown in FIG. 8. In FIG. 8, it is shown that the use of the conventional screen filter type module has a larger decrease in the amount of permeated water than in the case of using the module of the present invention. The decrease in the amount of permeated water is due to the conventional screen filter module having a length of 76 cm, so that the suction pressure is not evenly distributed on the surface of the hollow fiber membrane, so that the filtration phenomenon occurs, and the modules are laminated with four hollow fiber membrane plate sheets. As a result, it was determined that intercalation occurred as the MLSS concentration increased.

The hollow fiber membrane module according to the present invention has a structure that can minimize membrane contamination and intercalation blockage that may occur when directly filtration of wastewater having a high concentration of suspended solids, so that the filtration efficiency is excellent and the membrane cleaning cycle can be maintained for a long time. In addition, the quality of the treated water passed through is also excellent and can be used economically and efficiently for the treatment of high concentration suspended solids-containing waste water.

Claims (7)

(a) two or more hollow fiber membrane units in which bundles of hollow fiber membranes 1 arranged vertically side by side on a plane are fixed with both ends open by a fixing member 2; (b) a pair of connecting portions 3 for connecting the ends of the different hollow fiber membrane units in a vertical arrangement, and the pair of connecting portions 3 from the outside of the fixing member 2; H-shaped which consists of a pair of sealing part 4 which seals a hollow fiber membrane, and communicates in a central axis direction between a pair of connection part, and forms the permeate recovery part 5 which communicates with the open end of a hollow fiber membrane. Form union; And (c) one connecting portion 3 'surrounding the ends of the hollow fiber membrane unit at both ends, and sealing the hollow fiber membrane while combining the connecting portion 3' and the hollow fiber membrane unit from the outside of the fixing member 2; Consists of one sealing portion 4 'and includes a U-shaped union which communicates in the central axis direction and forms a permeate recovery portion 5' communicating with the open end of the hollow fiber membrane, The hollow fiber membrane has a wall thickness of 20 to 200 μm and an outer diameter of 200 to 2,000 μm, 2. A submerged hollow fiber membrane module for treating wastewater containing a high concentration of suspended solids having a length of 0.1 to 0.5 m as the length of each of two or more vertically arranged hollow fiber membrane units minimizing filtration. The method of claim 1, The hollow fiber membrane bundles are arranged at intervals of 0.4 to 0.6 mm, wherein each hollow fiber membrane bundle comprises 10 to 15 strands of hollow fiber membranes. delete delete delete The method of claim 1, A hollow fiber membrane module, characterized in that the H-shaped union and the U-shaped union has a thickness of 5 to 10mm. delete