JP2000079329A - Filter membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter membrane module wherein microorganisms such as pathogenic protozoa represented by cryptosporidium are hardly mixed into a filtrated water even when a hollow fiber membrane is broken. SOLUTION: A filter membrane module is provided with a treating container, a partition plate 4 for dividing this treating container into a stock soln. room and a filtrate room, at least one follow fiber membrane element 6 provided by being mounted on the partition plate 4 and using a hollow fiber membrane in this stock soln. room and a filter member 7 provided on the furthermore downstream side to the follow fiber membrane element 6 in relation to the flow direction of the stock soln. and contg. a filter medium with a larger pore diameter than the fine pore diameter of the hollow fiber membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration membrane module which can be suitably used for purifying industrial water or tap water.

[0002]

2. Description of the Related Art Membrane separation is a technique that is used in various fields because it is easy to save energy, space, and labor. This membrane separation method includes reverse osmosis, ultrafiltration, microfiltration, pervaporation, etc.
Various types of membranes, such as hollow fiber membranes, flat membranes, and tubular membranes, are used and applied depending on the characteristics of the object to be separated.

[0003] Among them, in the field using the microfiltration method,
2. Description of the Related Art Small disk filters and flat membrane pleated cartridge filters are used for the purpose of filtering a relatively clear liquid with a small amount of processing. In the field of using the ultrafiltration method, a flat membrane filter and a hollow fiber membrane filter are used for the purpose of producing ultrapure water, producing food, producing soft drinks, and the like.

However, in recent years, studies have been made to apply hollow fiber membranes used for such ultrafiltration to purification treatment for producing industrial water or tap water by treating river water or groundwater, Technologies have been developed that can be used for a long time on raw water having a relatively high turbidity.

The hollow fiber membrane or the hollow fiber membrane module using the same can have a very large filtration area per unit volume and a simple sealing mechanism for separating the stock solution to be treated and the filtrate. It has various advantages such as excellent water quality of the filtrate and easy operation management. In particular, in the purification treatment of raw water to obtain tap water, it is possible to obtain water of excellent quality compared to conventionally used coagulation sedimentation and sand filtration,
Since it is easy to achieve automation and labor saving, it is being actively introduced. Further, even if the raw water is contaminated with pathogenic protozoa such as Cryptosporidium, which have strong resistance to chlorine sterilization, attention has been paid to a technique capable of reliably removing these protozoa.

However, when a hollow fiber membrane module is used for the purpose of removing such protozoa, if the hollow fiber membrane breaks, the protozoa may be mixed into the filtered water. For normal water quality evaluation items such as turbidity, even if some of the hollow fiber membrane breaks, it is rarely a problem, but if there is a strong infectious protozoa such as Cryptosporidium in the raw water, However, a slight breakage of the hollow fiber membrane may cause a problem.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and even if a hollow fiber membrane breaks, microorganisms such as pathogenic protozoa represented by cryptosporidium are mixed into filtered water. An object of the present invention is to provide a filtration membrane module which is difficult to perform and a fresh water producing method using the same.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a processing container, a partition plate for partitioning the processing container into a stock solution chamber and a filtrate chamber, and the partition plate mounted in the stock solution chamber. Provided at least one using a hollow fiber membrane
A filter membrane comprising: a hollow fiber membrane element of the present invention; and a filter member provided on the downstream side of the hollow fiber membrane element with respect to the flow direction of the undiluted solution, the filter member including a filter medium having a pore diameter larger than the pore diameter of the hollow fiber membrane. It features a module.

Here, it is preferable that the filter member is disposed in the filtrate chamber.

[0010] It is also preferable that the filter member includes a support member that supports the filter medium, and it is also preferable that the filter member includes a microfiltration membrane.

Further, it is preferable that the filter member includes at least one porous body selected from the group consisting of a polymer sintered body having a communication hole, a sintered metal, ceramics and glass.

Further, the pore size of the filter material is 0.03 to 4 μm.
Is also preferably within the range.

Further, it is preferable that a space is provided between the hollow fiber membrane element and the filter member, and that a pressure measuring means for measuring the pressure in this space is provided.

It is also preferable to produce water using the above-mentioned filtration membrane module.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a filtration membrane module 1 according to one embodiment of the present invention is made of stainless steel (SU).
S304) a processing vessel constituted by a member including a stock solution chamber member 2 and a filtrate solution chamber member 3, a partition plate 4 made of stainless steel (SUS304) for dividing the processing vessel into a stock solution chamber and a filtrate chamber, It has a hollow fiber membrane element 6 mounted on the partition plate 4 in the stock solution chamber and a pore diameter larger than the pore diameter of the hollow fiber membrane 5 provided downstream of the hollow fiber membrane element 6 with respect to the flow direction of the stock solution. A filter member 7 including a stainless sintered filter (filter material). The hollow fiber membrane element 6 is placed in an acrylic outer cylinder,
It has a structure in which U-shaped 3,500 hollow fiber membranes 5 are accommodated, and a sealing and fixing portion 14 is sealed near the opening end. The raw liquid chamber member 2 is provided with a raw water inlet 8 for introducing raw water and nozzles 9 to 11.
Is provided with a filtered water port 12. The nozzle 9 opens and functions as a vent when introducing or discharging the raw water into the raw liquid chamber, and the nozzle 10 serves as a discharge port when discharging the raw water from the raw liquid chamber. The nozzle 11 is an air inlet for performing air scrubbing such as cleaning of a hollow fiber membrane. These nozzles 9-11
Can be isolated from the undiluted solution chamber when the filtration membrane module 1 is operated. The filter member 7 is fixed in the filtrate chamber via a packing 13 made of NBR, and forms a space 15.

In the state where the nozzles 9 to 11 are isolated from the raw liquid chamber, the raw water introduced from the raw water inlet 8 flows from the outside of the hollow fiber membrane 5 in the hollow fiber membrane element 6 to the inside of the hollow fiber membrane. Then, after reaching the space 15 between the hollow fiber membrane element 6 and the filter member 7, it is further filtered by the filter member 7 and flows out from the filtered water port 12 through the filtrate chamber.

In the present invention, the filter member is provided downstream of the hollow fiber membrane element in the flow direction of the stock solution. Thereby, even when the hollow fiber membrane is damaged or broken, the filtration is performed again with the filter member, so that microorganisms such as pathogenic protozoa do not easily enter the filtrate.

[0018] The filter member is preferably installed so as to filter again the entire amount of the filtrate passed through the hollow fiber membrane. For this purpose, for example, as shown in FIG. 1, the filtrate passing through the hollow fiber membrane leaks out of the filter membrane module or flows from the filtrate port by bypassing the filter member by using packing or the like. It is preferred that it is not.
As the material of the packing, NBR, silicon, or the like can be conveniently used.

Further, it is preferable that the filter member be disposed inside the filtrate chamber, because an extra space is not required as compared with the case where the filter member is installed outside the filtrate chamber.

The filter member used in the present invention contains a filter having a pore size larger than the pore size of the hollow fiber membrane.
As a filter material, for example, use of a microfiltration membrane is preferable because microorganisms such as pathogenic protozoa are less likely to be mixed into filtered water. As the material, for example, a polymer material can be used. In addition, it is preferable to include at least one kind of porous body selected from the group consisting of a polymer sintered body having a communication hole, a sintered metal, ceramics, and glass. As the polymer material, polyethylene, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl Vinyl ether copolymer, and chlorotrifluoroethylene-ethylene copolymer,
Polyvinylidene fluoride, polysulfone, polyether sulfone, and the like can be used, and it is preferable to use an ultrafiltration membrane or a microfiltration membrane using these. Further, a filtering material containing a sintered body of these polymers can also be used.

As the sintered metal, SUS304 or SUS304 is used.
Sintered fine particles such as 316 can be used. It is also preferable to use a sintered metal fiber microfiltration membrane using a fibrous material thereof.

The pore size of the filter is preferably in the range of 0.03 to 4 μm. Further, it is more preferably in the range of 0.05 to 2 μm, and still more preferably in the range of 0.1 to 1 μm. When the pore diameter is less than 0.03 μm, the pressure loss tends to increase, and clogging occurs due to foreign matter and the like, which tends to shorten the life. On the other hand, when it exceeds 4 μm, microorganisms such as pathogenic protozoa easily pass through the filter. The pore size of the filter media is 0.03 ~ 4μ
By being within the range of m, pathogenic protozoa such as Cryptosporidium can be efficiently removed.

Here, the pore size and the pore size refer to values calculated by measuring the water permeability (Lp) and the water permeation speed (Jv) of the sample and using the following equations (1) and (2). .

Jv = Lp · ΔP (1) Lp = (H / L) · (Rp ² / 8η) (2) ΔP: pressure difference between primary side and secondary side of sample H: moisture content of sample L : Sample thickness Rp: Pore size (pore size) η: Viscosity of water The water permeability of the filter material is 100 to 500,000 L / (m
² · h) / (kg / cm ² ), preferably 1,000 to 100,000 L / (m ² · h) /
(Kg / cm ² ), more preferably
10,000-100,000 L / (m ² · h) / (k
g / cm ² ). When the water permeability is less than 100 L / (m ² · h) / (kg / cm ² ), the pressure loss tends to be large, and 500,000
If it exceeds L / (m ² · h) / (kg / cm ² ), the filtration accuracy tends to decrease.

The filter member may be made of only a filtering material as shown in FIG. 1, but it is preferable to adopt a structure as shown in FIGS. That is, FIG.
The filter member 18 is covered with a support member 30 so that the filter member 18 is not deformed as shown in FIG. 12, the filter member 18 having the outer peripheral portion fixed by the fixing member 19b and the supporting member 30a having the outer peripheral portion fixed by the fixing member 19c as shown in FIG. Can be used. These shapes can be conveniently selected depending on the size, rigidity, sealability, etc. of the filter medium, but the use of a support member is preferable because deformation of the filter medium is easily prevented.

In FIGS. 10 to 12, the filter medium 1
8 is described as a flat plate, but in order to increase the effective area of the filter member, the cross-sectional shape is changed to a shape in which the bottom of the cylinder is opened as shown in FIG. 13 or a pleated shape as shown in FIG. It can also be shaped.

As the material of the fixing member, any material can be used as long as it can suppress the deformation of the filter medium to a certain extent and does not allow passage of microorganisms such as pathogenic protozoa, and can be conveniently selected from metals and plastics. .

The fixing member preferably has a structure in which the fixing member is in liquid-tight contact with the filter medium and the support member. For example, it is preferable that the fixing member is bonded to the filter medium or pressure-bonded through packing.

When a support member is used, it is preferable that the support member is formed in a mesh shape, a porous shape, or a slit shape so that the flow of the liquid is not hindered by the support member.

Next, a method of installing a filter member other than the method shown in FIG. 1 will be described with reference to FIGS. The filter member is provided on the downstream side of the hollow fiber membrane element with respect to the flow direction of the undiluted solution. Depending on the shape of the processing container or the module, the method of installing the filter member may be variously selected as described below.

First, in FIG. 2, a filter member 7a is arranged via a packing 13b on the open end side of each hollow fiber membrane element 6 mounted on the partition plate 4, and each is further fixed by a pressing plate 20. Have been. Packing 1
3b is arranged at the peripheral edge of the hollow fiber membrane element so as not to obstruct the flow of the filtrate, and the holding plate 20 also has a cross-sectional shape of the hollow fiber membrane element 6 so as not to obstruct the flow of the filtrate. It has a shape that is open at the same time, and has a structure for holding down the packing 13b. This holding plate is
It has a function of preventing the hollow fiber membrane element from rising or falling into the filtrate chamber.

FIGS. 3 and 4 show AA cross section and BB cross section of FIG. 2, respectively. The holding plate 20 has an opening formed in accordance with the arrangement state of the hollow fiber membrane elements 6, and has a structure that does not hinder the flow of the filtrate.

FIG. 2 shows a structure in which the holding plate 20 is arranged as a separate member to prevent the holding member 20 from floating into the filtrate chamber by the filtrate chamber member 3a. Also, it can be formed integrally with the filtrate chamber member. As the material of the pressing plate, the same material as that of the filtrate chamber member may be used, and metal, FRP, or the like is preferable.

FIG. 5 shows an example in which the filter member 7b is fixed to the filtrate chamber member 3a via the packing 13c. A space 15a is formed between the hollow fiber membrane element 6 and the filter member 7b. In this case, the filter member can also have a function of preventing the hollow fiber membrane element from rising or falling out of the filtration chamber, as in the holding plate shown in FIG.

FIG. 6 shows an example in which the filter member 7c is fixed to the partition plate 4 via a packing 13d.
A space 15b is formed between the hollow fiber membrane element 6 and the filter member 7c.

FIG. 7 shows an example in which a filter member 7d is fixed to the outlet end face of the filtered water port 12 via a packing 13e. A space 15c is formed between the hollow fiber membrane filter 6 and the filter member 7d.

FIG. 8 shows an example in which a cylindrical cartridge filter is used as the filter member 7f and is fixed to the filtration chamber member 3c and the partition plate 4 via a fixing plate 17. A space 15e is formed between the hollow fiber membrane element 6 and the filter member 7f.

FIG. 9 shows an example in which a plurality of disk-shaped filter members 7e are fixed to the filtrate chamber member 3b. In this example, a space 15d is formed between the hollow fiber membrane element and the filter member, and a pressure measuring means 16 for measuring the pressure in the space 15d is provided.

In the present invention, for example, as shown in FIG. 9, a space is provided between the hollow fiber membrane element and the filter member, and pressure measuring means for measuring the pressure in this space is provided. Is preferred. By providing this pressure measuring means, the hollow fiber membrane may be damaged,
It is possible to confirm a pressure increase in the case of breakage. Conventionally, as a method of detecting the breakage of the hollow fiber membrane and the like, it has been performed to measure the turbidity of the filtrate, but with this, it is difficult to detect the breakage of a very small number of hollow fiber membranes,
In addition, there is an inconvenience that turbid substances and microorganisms in the undiluted solution are mixed into the filtrate until the detection. In the present invention,
By providing the above-described filter member and providing the pressure measuring means, it is possible to check the damage or breakage of the hollow fiber membrane from the initial stage while suppressing the contamination of the filtrate with turbid substances and microorganisms, and to confirm the hollow fiber. Exchange of the membrane element and the like can be performed with good timing.

Further, by providing a pressure measuring means in the above space, the filtration pressure of the hollow fiber membrane and the filtration pressure of the filter member can be measured separately, and the state of the hollow fiber membrane and the filter member can be checked. It can be used for maintenance, for example, by knowing exactly when to replace them.

It is preferable to use a pressure gauge or a pressure sensor as the pressure measuring means. Further, the pressure measuring means may be provided fixed to the partition plate as shown in FIG.
It may be provided fixed to the filtrate chamber member.

A stock solution chamber member of the filtration membrane module of the present invention,
The material of the filtrate chamber member and the partition plate can be conveniently used such as metal or plastic, but it is preferable to use stainless steel, FRP, or the like having excellent pressure resistance and corrosiveness.

As the hollow fiber membrane element, one having a shape in which the inside of the hollow fiber membrane is open at the end of the partition plate can be used. In particular, it is preferable to use a hollow fiber membrane element having a structure in which a hollow fiber membrane bundle is U-shaped and housed in a case, and the vicinity of an opening end thereof is sealed with a resin or the like. Also, if the part to be mounted on the partition plate of the hollow fiber membrane element is formed hard using metal or resin,
It is preferable because the mounting is easy.

The portion of the hollow fiber membrane element in the stock solution chamber may have a structure in which the hollow fiber membrane is covered with a case. However, any structure may be used as long as the liquid in the stock solution chamber easily reaches the hollow fiber membrane. The hollow fiber membrane bundle may be disposed in the undiluted solution chamber without being covered with a case or the like.
Further, a structure in which a part or all of the outer periphery of the hollow fiber membrane bundle is wrapped with a protective sheet or a protective cylinder may be adopted.

As the material of the hollow fiber membrane, for example, polyethylene, polypropylene, polysulfone, polyether sulfone, polyvinyl alcohol, cellulose acetate, and polyacrylonitrile can be used.

In the above description, the external pressure type in which the liquid is supplied from the outside of the hollow fiber membrane and flows out to the inside has been described. However, the internal pressure type in which the liquid is supplied from the inside of the hollow fiber membrane and flows out to the outside. Good. In the case of the internal pressure type, a hollow fiber membrane having a shape in which the inside of the hollow fiber membrane is open is used on the stock solution chamber side of the hollow fiber membrane element. preferable.

By producing tap water or the like using the filtration membrane module of the present invention, even if the hollow fiber membrane is damaged or broken, pathogenic protozoa or microorganisms such as cryptosporidium in the filtered water can be obtained. It is possible to obtain water with a low possibility of contamination.

[0048]

EXAMPLES In order to confirm the effect of removing pathogenic protozoa such as Cryptosporidium, evaluation was performed using raw water containing fine particles having a diameter of 4 μm or more. In addition, in the conventional coagulated sedimentation sand filtration method, as a provisional guideline for controlling turbidity to 0.1 or less as a control standard for Cryptosporidium, this was also evaluated. (Example) A hollow fiber membrane bundle consisting of 3,500 polyacrylonitrile porous hollow fiber membranes having an outer diameter of 680 µm, an inner diameter of 400 µm, and an average pore diameter of 0.01 µm is bundled in a U-shape, and has a hard outer diameter of 110 mm and an inner diameter of 100 mm. A hollow fiber membrane element is manufactured by inserting it into a vinyl chloride pipe housing, sealing and fixing one end with an adhesive, then cutting a part of the sealing and fixing part to open the inside of the hollow fiber membrane. did. At this time, the other end of the housing is open. Next, this hollow fiber membrane element was used for an outer diameter of 510 mm and an inner diameter of 500 m.
7 pieces were inserted into a SUS304 processing container having a total length of 1,500 mm. The filter member is made of SUS304 sintered stainless steel fiber with a diameter of 450 mm and a height of 40 mm.
A filter member (filtration accuracy: 0.7 μm) molded into a disk shape and processed into a filter member having a shape as shown in FIG. 11 was used. As the supporting member, a mesh-shaped metal net having a spacing of 5 mm was used. This filter member was set in the above-mentioned processing container, and a filtration membrane module as shown in FIG. 1 was manufactured.

Further, 300 hollow fiber membranes of each of the seven hollow fiber membrane elements were cut in the vicinity of the adhesive fixing portion so that some raw water was not filtered by the hollow fiber membrane.

The filtration membrane module has a turbidity of 7.1.
Then, the whole amount of raw water containing 8.9 × 10 ⁸ particles / ml having a diameter of 4 μm or more was filtered at a flow rate of 8.3 l / min to measure turbidity and residual fine particles in the permeated water. As a result, the turbidity of the filtered water was 0.02, and the number of particles having a diameter of 4 μm or more was reduced to 10 particles / ml. The filtration pressure difference is 35 kP
a, which is small and substantially equal to the case of a comparative example in which no filter member is provided. (Comparative Example) A filtration membrane module was manufactured in the same manner as in Example except that no filter member was provided. When the same raw water as in the example was supplied to the filtration membrane module under the same conditions, the turbidity of the filtered water was 1.8, and particles having a diameter of 4 μm or more were 2.2 × 10 ⁸ particles / ml in the filtered water. Was included. The filtration pressure difference was 26 kPa.

[0051]

According to the present invention, a filtration membrane module comprises:
A processing vessel, a partition plate that partitions the processing container into a stock solution chamber and a filtrate chamber, and at least one hollow fiber membrane element using a hollow fiber membrane, which is provided in the stock solution chamber by being attached to the partition plate. And a filter member including a filter medium having a pore diameter larger than the pore diameter of the hollow fiber membrane provided on the downstream side of the hollow fiber membrane element with respect to the flow direction of the undiluted solution. However, since filtration can be performed again by the filter member, it is possible to make it difficult for microorganisms such as pathogenic protozoa to be mixed into the filtrate.

When the filter member is disposed in the filtrate chamber, no extra space is required as compared with the case where the filter member is disposed outside the filtrate chamber, and the filtrate module can be made compact.

Further, when the filter member includes a support member for supporting the filter medium, the filter medium is less likely to be deformed, and the filter medium is cracked or cracked to cause a pathogenic parasite in the filtrate. Such microorganisms can be prevented from entering.

When the filter member includes a microfiltration membrane, microorganisms such as pathogenic protozoa can be more effectively prevented from entering the filtrate.

Further, when the filter member contains at least one kind of porous body selected from the group consisting of a polymer sintered body having a communicating hole, a sintered metal, ceramics and glass, it is more effective. It is possible to prevent the above microorganisms and the like from being mixed into the filtrate.

The filter medium has a pore size of 0.03 to 4 μm.
When it is within the range, the above microorganisms and the like can be prevented from being mixed into the filtrate, the pressure loss can be reduced, and the life of the filter member can be prolonged.

Further, when a space is provided between the hollow fiber membrane element and the filter member and a pressure measuring means for measuring the pressure in this space is provided, the breakage of the hollow fiber membrane can be prevented at an early stage. And the replacement of the hollow fiber membrane element can be performed with good timing.

Further, by producing water using the above-mentioned filtration membrane module, it is possible to obtain water having a low possibility that pathogenic protozoa such as Cryptosporidium or microorganisms are mixed in the filtered water.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a filtration membrane module according to one embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to another embodiment.

FIG. 3 is a schematic sectional view taken along line AA in FIG. 2;

FIG. 4 is a schematic sectional view taken along line BB in FIG. 2;

FIG. 5 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to another embodiment.

FIG. 6 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to still another embodiment.

FIG. 7 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to another embodiment.

FIG. 8 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to still another embodiment.

FIG. 9 is a schematic longitudinal sectional view showing the vicinity of a filtrate chamber of a filtration membrane module according to another embodiment.

FIG. 10 is a schematic longitudinal sectional view showing a configuration of a filter member according to an embodiment of the present invention.

FIG. 11 is a schematic longitudinal sectional view showing a configuration of a filter member according to another embodiment.

FIG. 12 is a schematic longitudinal sectional view showing a configuration of a filter member according to another embodiment.

FIG. 13 is a schematic longitudinal sectional view of a filter medium according to an embodiment of the present invention.

FIG. 14 is a schematic longitudinal sectional view of a filter medium according to another embodiment.

[Explanation of symbols]

 1: Filtration membrane module 2: Stock solution chamber member 3: Filtration chamber member 3a: Filtration chamber member 3b: Filtration chamber member 3c: Filtration chamber member 4: Partition wall 5: Hollow fiber membrane 6: Hollow fiber membrane element 7 : Filter member 7a: Filter member 7b: Filter member 7c: Filter member 7d: Filter member 7e: Filter member 7f: Filter member 8: Raw water port 9: Nozzle (vent) 10: Nozzle (drain port) 11: Nozzle (air introduction) Mouth) 12: Filtration water port 13: Packing 13 a: Packing 13 b: Packing 13 c: Packing 13 d: Packing 13 e: Packing 13 f: Packing 14: Sealing fixing part 15: Space 15 a: Space 15 b: Space 15 c: Space 15 d: Space 15 e: Space 16: Pressure measuring means 17: Fixed plate 18: Filter material 18 a: Filter material 18 b: Filter Material 19: fixing member 19a: fixing member 19b: fixing member 19c: fixing member 20: pressing plate 30: support member 30a: support member

Claims (8)

[Claims] 1. A processing container, a partition plate for partitioning the processing container into a stock solution chamber and a filtrate chamber, and at least one of a hollow fiber membrane provided in the stock solution chamber and attached to the partition plate.
A hollow fiber membrane element, and a filter member provided on the downstream side of the hollow fiber membrane element with respect to the flow direction of the undiluted solution, including a filter member having a pore size larger than the pore size of the hollow fiber membrane. Characteristic filtration membrane module. 2. The filtration membrane module according to claim 1, wherein the filter member is disposed in the filtrate chamber. 3. The filtration membrane module according to claim 1, wherein the filter member includes a support member that supports the filter medium. 4. The filter member includes a microfiltration membrane.
The filtration membrane module according to claim 1. 5. The filter member according to claim 1, wherein the filter member includes at least one porous body selected from the group consisting of a polymer sintered body having a communication hole, a sintered metal, ceramics, and glass. A filtration membrane module according to any one of the above. 6. The filtration membrane module according to claim 1, wherein the pore size of the filtration material is in the range of 0.03 to 4 μm. 7. The filtration membrane according to claim 1, wherein a space is provided between the hollow fiber membrane element and the filter member, and pressure measurement means for measuring a pressure in the space is provided. module. 8. A fresh water producing method using the filtration membrane module according to claim 1.