TW202110528A - Hollow fiber membrane module and method for cleansing same - Google Patents

Abstract

This hollow fiber membrane module has: a container 1 having a treated-water outlet 5 and an upper discharge outlet 8; a plurality of hollow fiber membranes 2 for performing solid-liquid separation of raw water, the hollow fiber membranes 2 being arranged in the vertical direction within the container 1; an upper-end-securing part 3 that secures the upper ends of the hollow fiber membranes 2 and is arranged in an upper part within the container 1; a permeable-water chamber 7 formed above the upper-end-securing part 3, the permeable-water chamber 7 being communicated with the interiors of the hollow fiber membranes 2; piping L1 that supplies raw water into the container 1; and a central pipe 4 for carrying out bubbling cleansing. The central pipe 4 extends vertically below the upper-end-securing part 3 and is provided with a plurality of ejection holes 4a that eject air toward a peripheral side surface.

Description

Hollow fiber membrane module and its cleaning method

The present invention relates to a hollow fiber membrane module and a cleaning method thereof, in particular to a hollow fiber membrane module and a cleaning method thereof that can sufficiently clean and remove the turbidity attached to the membrane.

Hollow fiber membrane modules are widely used in the fields of pure water production or wastewater recycling as a unit for removing turbid components or organic matter. In the membrane of the hollow fiber membrane module, a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) is used according to the separation object. The former is usually pores of about 0.1 μm, and the latter is The pores are 0.005 μm to 0.5 μm.

When the suspended water supplied to the hollow fiber membrane module contains a large amount of turbidity or organic matter, not only the clogging of the membrane will occur, the frequency of backwashing and chemical cleaning will increase, and the frequency of membrane replacement will also increase. In order to prevent the clogging of the membrane, the usual method is to reduce the water flow per unit area of the membrane, but this method has a problem that the number of membranes installed increases.

Patent Document 1 proposes a backwashing method using air and water in order to improve the turbidity removal of the membrane. However, in this method, depending on the type and amount of turbidity, the removal of turbidity may not improve much, and a higher-performance backwashing method is required.

In general air cleaning, air is made to flow from the lower part of the membrane module to the upper part, but the strength of the air varies from top to bottom, so the air cannot spread over the entire membrane module, resulting in insufficient cleaning. In addition, if the lower drain is performed during air cleaning, the air does not penetrate into the membrane module but is discharged. Therefore, the drain can only be drained from the upper part of the module, such as the circulation part. Therefore, the turbidity of the entire membrane module peeled off by air washing may adhere to the upper part of the membrane.

Patent Document 2 discloses a method for cleaning a hollow fiber membrane module. The hollow fiber membrane module includes: a container with a treated water outlet and a concentrated water outlet; a central pipe for supplying raw water into the container; and a plurality of hollows The silk membrane is a hollow fiber membrane used to separate raw water into permeated water and concentrated water, and is arranged in the vertical direction in the container; the upper end fixing part fixes the upper end of the hollow fiber membrane and is arranged in the container And the permeated water chamber is formed on the upper side of the upper end fixing part, and the inside of each hollow fiber membrane is communicated; and the central tube extends in the up and down direction on the lower side of the upper end fixing part, on the side peripheral surface A plurality of spout holes for spouting raw water are provided, and a drain port is provided in the lower part of the container, and the drain port will perform washing at the time of bubbling washing by blowing gas from the plurality of spout holes Waste water is discharged; the cleaning method of the hollow fiber membrane module performs bubbling cleaning in which gas is blown in from the plurality of ejection holes, and the cleaning wastewater is discharged from the drain.

In Patent Document 2, the central pipe including the unit for introducing raw water and gas is installed in the center of the module, and air is blown into the module from the central pipe, so that the strength of the clean air generated from the upper and lower sides of the module can be poor. Ease. In Patent Document 2, since the raw water is transported from the central tube, the membrane on the central side close to the central tube has a higher raw water pressure than the membrane on the outer peripheral side close to the housing. The amount of filtration is more than that of the membrane on the outer peripheral side. Therefore, the film contamination in the module is uneven. In other words, a high load is applied to the hollow fiber membrane on the center side of the module, and membrane fouling is likely to occur, or the effective membrane area decreases due to the progress of membrane fouling. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2005-88008 Patent Document 2: Japanese Patent Laid-Open No. 2017-176966

[The problem to be solved by the invention] The present invention is formed in view of the above-mentioned existing actual situation, and its object is to provide a hollow fiber membrane module and a cleaning method thereof that can completely and sufficiently remove the turbidity attached to the hollow fiber membrane.

[Means to solve the problem] The hollow fiber membrane module of the present invention includes: a container with a treated water outlet at the upper part; a raw water supply unit for supplying raw water to the lower part of the container; a plurality of hollow fiber membranes are hollow fiber membranes for solid-liquid separation of raw water , And arranged in the container in the up-and-down direction; the upper end fixing part fixes the upper end part of the hollow fiber membrane and is arranged at the upper part of the container; the permeable water chamber is formed on the upper side of the upper end fixing part, and each hollow The inner part of the silk membrane is communicated; a central tube extends in the up and down direction on the lower side of the upper end fixing part, and is provided with a plurality of ejection holes for ejecting gas on the side peripheral surface; and a discharge unit that discharges the gas from the container And washing wastewater.

In one aspect of the present invention, the lower end of the central tube faces the opening of the bottom surface of the container.

In one aspect of the present invention, a unit for supplying gas is provided at the lower part of the container.

In the cleaning method of the hollow fiber membrane module of the present invention, the first bubbling cleaning in which gas is blown in from the plurality of ejection holes of the center pipe is performed, and exhaust gas and cleaning wastewater are discharged from the discharge unit.

In one aspect of the present invention, at least one of the following foaming cleaning is performed: a first foaming cleaning, blowing gas from a plurality of ejection holes of the center tube; and a second foaming cleaning , Gas is blown in from a gas supply unit installed at the lower part of the container, and exhaust gas and washing wastewater are discharged from the discharge unit.

In one aspect of the present invention, before or after the first foaming washing, the second foaming washing is performed, and the washing wastewater is discharged from the container.

In one aspect of the present invention, the backwashing in which backwashing water is supplied from the treated water outlet is performed simultaneously with the first foaming washing and/or the second foaming washing.

In one aspect of the present invention, a chemical liquid is added to the backwash water.

In one aspect of the present invention, the flow rate of the gas passing through the central tube is 50 NL/min to 300 NL/min.

[Effects of the invention] In the hollow fiber membrane module of the present invention, since the center tube extends in the vertical direction in the container, and air is blown in from a plurality of ejection holes provided in the center tube to perform bubbling and cleaning, the air spreads over the entire membrane module, which can be The turbidity adhering to the hollow fiber membrane is completely and fully removed.

In addition, by introducing the raw water from the lower part of the module, the drift in the filtration step can be reduced, and the membrane can be used uniformly, thus preventing (including suppressing) the progress of local membrane fouling or the decrease in membrane area caused by this.

By installing a dispersing plate with small holes, the raw water is dispersed and the drift of the raw water is further reduced.

Hereinafter, the embodiment will be described with reference to FIGS. 1 to 3.

Fig. 1 is a cross-sectional view showing the structure of the hollow fiber membrane module of the present embodiment. As shown in FIG. 1, the hollow fiber membrane module includes a container 1 arranged with the axis of the cylinder in the vertical direction (vertical direction in this embodiment). A plurality of hollow fiber membranes 2 are arranged in the container 1.

The hollow fiber membrane 2 is fixed to the upper side of the container 1 by a potting part 3 made of synthetic resin as a fixing part, and is not fixed to the lower side of the container 1. As the synthetic resin of the potting part 3, epoxy resin (epoxy resin) can be used, for example.

For example, the hollow fiber membrane 2 is incorporated into a U-shape, and the potting part 3 is used to fix both ends of the hollow fiber membrane. In this case, the middle part of the hollow fiber membrane 2 is located at the lower part of the container 1.

In addition, in the case of using the hollow fiber membrane 2 with one end opened and the other end sealed, one end of the opened hollow fiber membrane 2 is fixed by the potting part 3, and the sealed other end is arranged in the container 1 Lower part.

The hollow fiber membrane 2 may be any of a UF membrane, an MF membrane, or the like. The hollow fiber membrane 2 is not particularly limited, and a hollow fiber membrane having an inner diameter of 0.2 mm to 1.0 mm, an outer diameter of 0.5 mm to 2.0 mm, and an effective length of about 300 mm to 2500 mm is generally used. Preferably, 500 to 70,000 such hollow fiber membranes 2 are filled in the container 1 with a total membrane area of about 5 m ² to 100 m ² . There is no particular limitation on the membrane material of the hollow fiber membrane 2, and polyvinylidene fluoride (PVDF), polyethylene (polyethylene), polypropylene (polypropylene), etc. can be used.

A treated water chamber (permeated water chamber) 7 and a raw water chamber 10 are respectively formed on the upper side and the lower side of the potting part 3. The upper end side of the hollow fiber membrane 2 penetrates the potting part 3, the opening at the upper end faces the treatment water chamber 7, and the inside of the hollow fiber membrane 2 communicates with the treatment water chamber 7. When the hollow fiber membrane 2 is incorporated into a U-shape, both ends of the hollow fiber membrane 2 penetrate the potting part 3.

The potting part 3 has a disk shape, for example, and the outer peripheral surface or the outer peripheral edge part contacts the inner surface of the container 1 in a watertight manner.

Inside the container 1 (raw water chamber 10), the center pipe 4 extends in a substantially vertical direction (the axial direction of the container 1). The center tube 4 is arranged along the center axis of the container 1, for example. The center pipe 4 is a round pipe with a closed front end (upper end), and a plurality of ejection holes 4a are integrally provided on the side peripheral surface, spanning up and down and at intervals in the circumferential direction. The number of ejection holes 4a is not particularly limited, and is, for example, about 5 to 50. The size or shape of the ejection hole 4a is not particularly limited, and is, for example, a circular shape with a diameter of 5 mm to 500 mm. The inner diameter of the center tube 4 is, for example, about 10 mm to 20 mm.

The height (length in the vertical direction) of the center tube 4 is not particularly limited, and it is preferable that the upper end of the center tube 4 is located near the lower surface of the potting part 3. In addition, the upper end of the center tube 4 can also be buried in the potting part 3.

The lower end of the center tube 4 faces the opening 11 of the bottom surface of the container 1. A raw water piping L1 is connected to the opening 11, and a pump P1 and a valve V1 are provided in the raw water piping L1. Compared with the valve V1 of the raw water pipe L1, the air introduction pipe L2 is branched from the container 1 side, and the air introduction pipe L2 is provided with a valve V2.

Compared with the valve V1 of the pipe L1, a pipe L7 for discharging washing wastewater is connected to the container 1 side, and a valve V7 is provided in the pipe L7.

By opening and closing the switching valve V1 and the valve V2, the supply of raw water/air to the container 1 can be switched. By opening the valve V1 and closing the valve V2 and the valve V7, the raw water can be supplied from the lower portion of the raw water chamber 10 by pumping the raw water through the raw water piping L1 by the pump P1.

By closing the valve V1 and the valve V7, and opening the valve V2, air is supplied from the air introduction pipe L2, and air bubbles can be supplied from the opening 11, and the central filament membrane 2 can be foamed and washed. The valve V1 and the valve V2 may be opened, and a gas-liquid mixed flow may be ejected from the opening 11.

An air pipe L8 is connected to the lower part of the center pipe 4, and a valve V8 is provided in the pipe L8. By supplying air from the pipe L8, air bubbles can be ejected in the radial direction from the ejection hole 4a of the center pipe 4, and the hollow fiber membrane 2 can be bubbled and cleaned.

An outlet 5 for treated water (membrane permeable water) is provided on the top of the container 1. In addition, an upper discharge port 8 is provided on the upper part of the side surface of the container 1. The upper discharge port 8 is provided near the lower surface of the potting part 3. The distance from the potting part 3 to the upper edge of the upper discharge port 8 is preferably 0 mm to 30 mm, particularly preferably about 0 mm to 10 mm. A pipe L5 is connected to the upper discharge port 8, and a valve V5 is provided in the pipe L5.

The treated water outlet 5 is connected with a treated water take-out pipe L3, and treated water (membrane permeated water) is taken out through the treated water take-out pipe L3. The treated water is stored in the treated water tank 9.

One end of the backwash water pipe L4 is connected to the treated water take-out pipe L3 at a position between the valve V3 provided in the treated water take-out pipe L3 and the treated water outlet 5. The other end of the backwash water pipe L4 is connected to the treated water tank 9. The backwash water pipe L4 is provided with a valve V4 and a pump P2. By closing the valve V3 and opening the valve V4, the treated water flows from the treated water outlet 5 to the raw water chamber 10 via the backwash water pipe L4 by the pump P2, and the hollow fiber membrane 2 can be backwashed. . FIG. 1 shows a configuration in which the backwash water pipe L4 is connected to the treated water tank 9 and the treated water is used for the backwash water, but the backwash water may be raw water.

The waste water accompanying the backwash may be discharged from the opening 11 through the pipe L7, or may be discharged from the upper discharge port 8 through the pipe L5. The discharge from the opening 11 and the discharge from the upper discharge port 8 may be simultaneously performed, or may be performed sequentially (alternately). By performing the discharge of the backwash water from the pipe L7 and the discharge of the backwash water from the upper discharge port 8 at the same time or alternately, the turbidity peeled from the hollow fiber membrane 2 can be discharged efficiently.

A chemical liquid addition unit (not shown in the figure) for adding chemical liquid to the backwash water flowing in the backwash water piping L4 may also be provided. The chemical solution to be added is sodium hypochlorite, strong alkaline agent, strong acid agent, etc., which are selected according to the film attachment. For example, in the case where the organic film is a deposit containing organic turbid or the like, preferably sodium hypochlorite 0.05 mgCl ₂ L of residual embodiment _{2 /L~0.3 mgCl} / add.

In the filtration process using the hollow fiber membrane module, the valve V1 and the valve V3 are set to open, and the valve V2, valve V4, valve V5, valve V7, and valve V8 are set to close, so that the pump P1 is operated from the opening 11 Raw water is supplied to the raw water chamber 10. This embodiment is a dead end flow, and the permeated water that has passed through the hollow fiber membrane 2 is taken out from the treated water outlet 5 as treated water, and is stored in the treated water tank 9 through the treated water take-out pipe L3.

However, it is also possible to perform filtration treatment using an external pressure type in which raw water is circulated in a cross flow method on the outside of the hollow fiber membrane 2. In this case, the concentrated water that has not passed through the hollow fiber membrane 2 is discharged from the upper discharge port 8 through the pipe L5. The discharged concentrated water and raw water may be mixed and supplied to the container 1 for circulation.

If this filtration treatment is continued, turbidity is accumulated in the hollow fiber membrane 2. Therefore, after the filtration process is performed for a predetermined period of time, or when the amount of treated water is reduced, a cleaning process for cleaning the turbidity captured by the hollow fiber membrane 2 is performed.

In the first aspect of the method of cleaning the hollow fiber membrane module, the valve V8 is opened, the valves V1 and V2 are closed, and the multiple ejection holes 4a of the center tube 4 are directed to the hollow fiber. The film 2 is cleaned by blowing air into the first bubbling.

At this time, one or both of the valve V5 and the valve V7 are opened, and exhaust gas and washing wastewater are discharged. The valve V5 and the valve V7 may be opened alternately.

In the second aspect of the method of cleaning the hollow fiber membrane module, at least one of the following foaming cleaning is performed: the first foaming cleaning, the valve V8 is set to open, and the valve V1 is set to open. , The valve V2 is set to be closed, and air is blown into the hollow fiber membrane 2 from the multiple ejection holes 4a of the central pipe 4; and the second foaming cleaning, the valve V2 is set to open, and the valves V1 and V8 are set to closed , Air is blown into the hollow fiber membrane 2 from the opening 11. At this time, one or both of the valve V5 and the valve V7 are opened, and exhaust gas and washing wastewater are discharged. The valve V5 and the valve V7 may be opened alternately.

In one aspect of the second aspect, before or after the first foaming washing, the second foaming washing is performed, and the washing wastewater is discharged from the container.

In either of the first form and the second form of the cleaning method, the backwash water can be supplied from the treated water outlet 5 at the same time as the first foaming cleaning and/or the second foaming cleaning To the backwashing of the treatment water chamber 7.

In order to perform foaming washing and backwashing at the same time as described above, specifically, for example, valve V1, valve V3, and valve V7 are closed, and valve V2, valve V4, valve V5, and valve V8 are opened. The opening 11 and the center tube 4 blow air into the container 1 to foam, and the pump P2 is operated, and the treated water is sent to the hollow fiber membrane 2 as backwashing water through the treated water chamber 7 for backwashing . It is also possible to add chemical liquids to the backwash water. The washing wastewater and waste air are discharged from the upper discharge port 8 to the outside of the system through the pipe L5. After foaming, the washing waste water may be discharged from the pipe L7 by opening the valve V7.

In either of the first form and the second form, the amount of air supplied from the central pipe 4 is preferably about 30 NL/min to 500 NL/min, particularly preferably 50 NL/min to 300 NL/min .

The center tube 4 is provided with a plurality of ejection holes 4a throughout the entire vertical direction. Therefore, the hollow fiber membrane 2 is also sprayed with air bubbles, including the vicinity of the upper end fixing portion of the hollow fiber membrane 2 (near the potting part 3) , Can thoroughly wash and remove the turbidity. In addition, even if the air volume during foaming and washing is increased, the hollow fiber membrane 2 can be prevented from being twisted or bent compared to a method in which air flows only from the lower part of the module to the upper part.

Backwashing can also be air backwashing instead of water backwashing. In the foaming and washing, air may only be ejected from the center pipe 4. In addition, a gas-liquid mixed flow may be supplied from the central pipe 4 instead of air.

In the present invention, as shown in FIG. 2, a dispersing plate 12 having a plurality of small holes 12 a may be provided in the lower part of the container 1 to disperse the raw water from the opening 11 in the container 1. In FIG. 2, the dispersion plate 12 is arranged at a lower position than the lower end of the hollow fiber membrane 2.

In the present invention, the dispersion plate 12 is constituted by a potting material. As shown in FIG. 3, the lower end of the hollow fiber membrane 2 may be embedded in the dispersion plate 12. In FIG. 3, only a part of the small holes 12 a is shown in the figure, but in reality, they are provided over the entire surface of the dispersion plate 12.

The above-mentioned embodiment is an example of the present invention, and the present invention may also be adopted in forms other than those shown. [Example]

[Example 1] In the hollow fiber membrane module including the hollow fiber membrane module shown in FIG. 3, raw water was circulated through the pipe L1 for 30 minutes to perform filtration treatment. After storing tap water in the original water tank, adding 10 mg/L of bentonite and sodium bicarbonate manufactured by Kishida Chemical, adjust the pH to 8.0 using sulfuric acid manufactured by Kishida Chemical. A pump was used to send water from a raw water tank to a flocculation tank, and the residence time was set to 10 minutes. In front of the flocculation tank, water containing 100 mg/L of industrial ferric chloride (concentration of 38%) is used as raw water. The structure of the hollow fiber membrane module is as follows.

Container 1: The inner diameter is 200 mm and the height is 1500 mm. Hollow filament: Polyvinylidene fluoride UF membrane with an outer diameter of 1.4 mm. The membrane area is 32 m ² Central tube 4: The length extending in the container 1 is 1300 mm, the inner diameter is 13 mm, and the outer diameter is 18 mm. Ejection hole 4a: diameter of 10 mm, 48 small holes of dispersing plate 12 12a: diameter of 8 mm, 44

After the filtration process, air is supplied from the center pipe 4 to perform foaming washing, and back washing is performed. The washing treatment is performed for 1 minute. The backwash water is discharged from the upper discharge port 8. The supply amount of air for foaming was set to 80 NL/min. The feed water amount for backwashing is set to 80 L/min, and the feedwater for backwashing uses filtered water.

The filtration treatment and the washing treatment were alternately performed 5 times, respectively. Collect the backwash water discharged in each cycle and measure the turbidity quality of the backwash water. Table 1 shows the mass of turbidity discharged in the backwash (turbidity removal rate) relative to the total mass of turbidity supplied in the 5 cycles.

[Example 2] Except that the backwash water was discharged from the pipe L7 through the opening 11, the same treatment as in Example 1 was performed. The measurement results are shown in Table 1.

[Example 3] The same process as in Example 2 was performed except that before air was supplied from the center pipe 4, a step of performing backwashing for 30 seconds and draining the backwash water from the upper discharge port 8 was added. The measurement results are shown in Table 1.

[Example 4] The same treatment as in Example 3 was performed except that the supply amount of air for foaming was set to 150 NL/min. The measurement results are shown in Table 1.

[Example 5] The same treatment as in Example 4 was performed except that _{300 mgCl 2} /L of sodium hypochlorite was added to the backwash water. The measurement results are shown in Table 1.

[Example 6] In addition to supplying air from the center pipe 4, the foaming cleaning is additionally performed by supplying air from the lower opening 11 of the container 1 at 150 NL/min for 30 seconds, and the waste water and waste air are discharged from the upper discharge port 8. Except for the steps, the same processing as in Example 4 was performed. The measurement results are shown in Table 1.

[Comparative Example 1] The same treatment as in Example 1 was performed except that the hollow fiber membrane module without the center tube 4 was used, and the bubbling washing using the center tube 4 was omitted. The measurement results are shown in Table 1.

[Comparative Example 2] Except for the following conditions, the same treatment as in Comparative Example 1 was performed, that is, the hollow fiber membrane module without the center tube 4 was used, and the air cleaning using the center tube 4 was omitted, instead of using the hollow fiber membrane for backwashing. The lower opening 11 of the container of the module supplies 80 NL/min of foaming air, and the backwash water and waste air are discharged from the upper discharge port 8. The measurement results are shown in Table 1.

[Table 1] Turbidity elimination rate% Example 1 32 Example 2 37 Example 3 45 Example 4 70 Example 5 76 Example 6 91 Comparative example 1 0.9 Comparative example 2 28

As shown in Table 1, the turbidity of Example 1 by washing is compared with washing with only backwashing (Comparative Example 1) and washing with bubbling air from the lower part of the container (Comparative Example 2) The elimination rate is high.

In Example 2, by draining the washing waste water from the drain port at the lower part of the container, a higher turbidity removal rate than washing (Example 1) in which the washing waste water was discharged from the upper drain port was obtained.

In Example 3, by adding back washing before washing in Example 2, a turbidity elimination rate higher than that in Example 2 was obtained.

In Example 4, by increasing the amount of bubbling air from 80 NL/min to 150 NL/min, a higher turbidity removal rate than Example 3 was obtained.

In Example 5, by adding an oxidizing agent to the backwash water, a turbidity elimination rate higher than the non-addition condition (Example 4) was obtained.

In Example 6, prior to the washing in Example 4, air washing with bubbling air supplied from the lower part of the container was introduced to obtain a turbidity removal rate higher than that in Example 4.

[Example 7] The hollow fiber membrane module used in Example 1 circulated well water, and the time-dependent change of the differential pressure between the membranes was measured. The results are shown in Figure 5.

[Comparative Example 3] Using the hollow fiber membrane module shown in FIG. 4, the same test as in Example 7 was performed. The results are shown in Figure 5.

In addition, in FIG. 4, the opening 11 and the waste water pipe L7 are omitted, and instead, the drain port 6 is provided in the lower part of the side surface of the container 1. The drain port 6 is provided near the bottom surface of the container 1. A pipe L6 is connected to the drain port 6, and a valve V6 is provided in the pipe L6. In addition, the air pipe L8 is omitted, and the pipe L1 is connected to the lower part of the center pipe 4 instead. The structure of the hollow fiber membrane module of FIG. 4 is as follows.

Container 1: The inner diameter is 200 mm and the height is 1300 mm. Hollow filament: UF membrane made of polyvinylidene fluoride with an outer diameter of 1.25 mm. The membrane area is 30 m ² Central tube 4: The length extending in the container 1 is 1000 mm, the inner diameter is 20 mm, and the outer diameter is 25 mm. Ejection hole 4a: 10 mm diameter, 10

As shown in FIG. 5, compared with Comparative Example 3 in which raw water was supplied from the central pipe, Example 7 in which raw water was supplied from the lower portion of the raw water chamber was stabilized while suppressing the increase in the differential pressure between the membranes. The reason is that because the structure of the present invention is difficult to generate the bias flow of the raw water in the module, the entire membrane can be used for filtration completely, so there is no local acceleration of membrane fouling, and the resulting effective membrane area will not be affected. decline.

Although the present invention has been described in detail using specific aspects, those skilled in the art will understand that various changes can be made without departing from the intent and scope of the present invention. This application is based on Japanese Patent Application 2019-060929 filed on March 27, 2019, and the entire content is incorporated by reference.

1: container 2: Hollow fiber membrane 3: potting department 4: Central tube 4a: Ejection hole 5: Treated water outlet 6: Drain 7: Treatment water chamber (permeate water chamber) 8: Upper discharge port 9: Treatment sink 10: Raw water room 11: opening 12: Dispersion plate 12a: small hole L1: Raw water piping L2: Piping for air introduction L3: Processed water removal piping L4: Backwash water piping L5, L6: Piping L7: Piping (piping for wastewater) L8: Piping (piping for air) P1, P2: pump V1, V2, V3, V4, V5, V6, V7, V8: Valve

Fig. 1 is a cross-sectional view of the hollow fiber membrane module of the embodiment. Fig. 2 is a cross-sectional view of a hollow fiber membrane module according to another embodiment. Fig. 3 is a cross-sectional view of a hollow fiber membrane module according to another embodiment. Fig. 4 is a cross-sectional view of a conventional hollow fiber membrane module. FIG. 5 is a graph showing the results of Example 7 and Comparative Example 3. FIG.

1: container

2: Hollow fiber membrane

3: potting department

4: Central tube

4a: Ejection hole

5: Treated water outlet

7: Treatment water chamber (permeate water chamber)

8: Upper discharge port

9: Treatment sink

10: Raw water room

11: opening

L1: Raw water piping

L2: Piping for air introduction

L3: Processed water removal piping

L4: Backwash water piping

L5: Piping

L7: Piping (piping for wastewater)

L8: Piping (piping for air)

P1, P2: pump

V1, V2, V3, V4, V5, V7, V8: Valve

Claims (9)

A hollow fiber membrane module includes: The container has a treated water outlet on the upper part; The raw water supply unit supplies raw water to the lower part of the container; A plurality of hollow fiber membranes are hollow fiber membranes used for solid-liquid separation of raw water, and are arranged in the vertical direction in the container; The upper end fixing part fixes the upper end part of the hollow fiber membrane and is arranged at the upper part of the container; The permeable water chamber is formed on the upper side of the upper end fixing part, and the inside of each hollow fiber membrane is connected; A central tube, which extends in the up-down direction on the lower side of the upper end fixing part, and is provided with a plurality of ejection holes for ejecting gas on the side peripheral surface; and The discharge unit discharges gas and wash waste water from the container. The hollow fiber membrane module as described in item 1 of the scope of patent application, wherein The lower end of the central tube faces the opening of the bottom surface of the container. Such as the hollow fiber membrane module described in item 1 or item 2 of the scope of patent application, wherein A unit for supplying gas is provided in the lower part of the container. A method for cleaning hollow fiber membrane modules is a method for cleaning the hollow fiber membrane modules as described in any one of items 1 to 3 in the scope of patent application, characterized in that: A first bubbling cleaning in which gas is blown in from the plurality of ejection holes of the center pipe is performed, and exhaust gas and cleaning wastewater are discharged from the discharge unit. A method for cleaning hollow fiber membrane modules is a method for cleaning the hollow fiber membrane modules as described in item 3 of the scope of patent application, characterized in that: Perform at least one of the following bubbling cleaning: first bubbling cleaning, in which gas is blown from the plurality of ejection holes of the center tube; and second bubbling cleaning, from the first bubbling cleaning provided in the container The lower gas supply unit blows in gas; and The exhaust gas and washing wastewater are discharged from the discharge unit. The cleaning method of hollow fiber membrane module as described in item 5 of the scope of patent application, wherein Before or after the first foaming and washing, the second foaming and washing is performed, and the washing wastewater is discharged from the container. Such as the cleaning method of hollow fiber membrane module described in any one of item 4 to item 6 of the scope of patent application, wherein Simultaneously with the first foaming washing and/or the second foaming washing, backwashing in which backwashing water is supplied from the treated water outlet is performed. The cleaning method of hollow fiber membrane module as described in item 7 of the scope of patent application, wherein A chemical liquid is added to the backwash water. The method for cleaning hollow fiber membrane modules as described in any one of items 4 to 8 of the scope of patent application, wherein The flow rate of the gas passing through the central tube is 50 NL/min to 300 NL/min.

Images