JPH11290658A - Membrane module and concentration device with membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane module for recovering a concentrate quickly without waste. SOLUTION: A membrane module is provided with a plane membrane 9, a raw water side housing 2 introducing raw water onto the surface of the plane membrane and a permeated water side housing 3' for clamping the peripheral edge of the plane membrane 9 together with the raw water side housing 2 while keeping the liquid-tightness in the facial direction of the plane membrane and collecting permeated water permeating the plane membrane, and a mating surface of the permeated water side housing to be mated with the raw water side housing through the peripheral edge of the plane membrane forms one same plane surface inside and outside of liquid-tightness keeping sections 7 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a membrane module, and more particularly to a membrane module for filtering and concentrating raw water containing microorganisms such as cryptosporidium.
Further, the present invention relates to a concentrator provided with the membrane module.

[Prior art]

[0002] Some microorganisms such as protozoa and fungi are difficult to detect because there is no means for culturing. For example,
Cryptosporidium, a pathogenic protozoan parasite in the digestive tract of mammals. The protozoa can be parasitized using drinking water as a medium, and inhabit oocysts in rivers, lakes, and the like that serve as water sources for water purification plants. Cryptosporidium oocysts are present in only a few individuals in 10 L of water and do not grow outside the host organism. Therefore, when Cryptosporidium is detected from raw water such as river water, it is necessary to concentrate 20 L or more of raw water to several tens to several hundred mL.

[0003] Conventionally, a membrane module utilizing filtration by a membrane has been used for concentrating raw water containing microorganisms. Above all, a general purpose is a flat membrane module called a membrane filter, and there are a total filtration type and a type provided with a stirrer (blade).

FIG. 6 shows an example of a membrane module of the total filtration type.
FIG. The housing of the membrane module 26 shown in FIG. 6 includes a raw water side housing 27 having a raw water inlet 29 and a permeated water side housing 28 having a permeated water outlet 30. Both housings are fixed to each other by screws 34 via the O-ring 31 while sandwiching the periphery of the flat membrane 32. The raw water is guided from the raw water inlet 29 to the membrane surface of the flat membrane 32 and concentrated. When the raw water is concentrated, the concentrate accumulates on the membrane surface of the flat membrane 32, and the permeated water is collected by the flow path member 33 in the permeated water side housing 28 and discharged from the permeated water outlet 30. The concentrate is recovered by disassembling the membrane module 26 and scraping it off with a scraper. Since the filtration rate decreases as the amount of concentrate accumulated on the surface of the flat membrane 32 increases, the concentrate must be collected as needed.

[0005]

However, in the conventional total filtration type membrane module 26 shown in FIG. 6, since the flat membrane area is as small as 530 cm ^{2 at the} maximum, the flat membrane surface is immediately covered with the concentrate. I will. Therefore, decomposition of the membrane module and recovery of the concentrate must be performed frequently, and it takes a long time to concentrate the entire amount. If the filtration rate is significantly reduced, the flat membrane must be replaced. Further, in the conventional membrane module 26, since the flat membrane 32 is stuck in the concave portion of the permeated water side housing 28, it is not easy to collect the concentrate by the scraper, and it takes time, and the concentrate is lost. Likely to be. Therefore, it is difficult to perform an accurate microbial test.

[0006] In the type of membrane module provided with a stirrer, although the flat membrane can be prevented from being covered with the concentrate to some extent, the membrane area is smaller than that of the total filtration type, so that it takes time to concentrate. . Also,
Since the concentrate easily adheres to the dead space, the recovery of the concentrate is not as easy as in the case of the whole filtration type. In addition, there is a type in which a tank and a stirrer are integrated with a total filtration type membrane module, but not only the above-mentioned problem is not solved, but also it is very expensive.

[0007] Therefore, an object of the present invention is to provide a membrane module that can rapidly recover a concentrate without waste. Further, another object of the present invention is to provide a concentrator provided with the membrane module.

[0008]

A membrane module according to the present invention comprises a flat membrane, a raw water side housing for guiding raw water to the membrane surface of the flat membrane, and a raw water side housing while maintaining liquid tightness in the plane direction of the flat membrane. A permeate-side housing for holding the perimeter of the flat membrane together and collecting permeate permeating through the flat membrane, wherein the permeate-side housing is combined with the raw water-side housing via the perimeter of the flat membrane. Are characterized in that the mating surfaces are flush with each other inside and outside the liquid-tight holding portion.

[0009] The concentrating apparatus of the present invention is characterized by comprising this membrane module and a differential pressure generating means serving as a driving source for passing raw water through the flat membrane. The differential pressure generating means includes a vacuum pump connected to the permeated water side housing and a pressurized tank connected to the raw water side housing.
When a suction pipe having a trap is connected to the vacuum pump, the concentrate can be recovered by sucking the concentrate with the pipe. When a vacuum pump is used as the differential pressure generating means, it is preferable that the vacuum pump can be selectively opened to either the permeated water side housing or the suction pipe.

The operation of the present invention is as follows. Raw water is guided to the flat membrane surface by the raw water side housing. Since the flat membrane is sandwiched between the two housings while maintaining the liquid tightness at the periphery thereof, the raw water guided to the membrane surface spreads within an area surrounded by the liquid tight holding portion, and is filtered by the permeated water side housing. At the same time, the concentrate accumulates in the above-mentioned area of the film surface on the raw water side. The concentrate is collected by an appropriate means such as scraping or sucking. In the present invention, since the mating surface of the permeated water side housing forms the same plane inside and outside the liquid-tight holding portion, the outer surface of the liquid-tight holding portion can be a relief when the concentrate is collected. Therefore, regardless of whether scraping is performed with a tool such as a scraper or suctioning with a suction pipe, the tip of the tool or the pipe spreads to every corner reaching the liquid-tight holding portion. As a result, the concentrate can be quickly recovered without waste.

Further, when a projection penetrating the flat membrane is provided on the mating surface of the permeated water side housing outside the liquid tight holding portion, the flat membrane is fixed to the permeated water side housing, and the condensate is removed with a tool such as a scraper. Concentrate recovery is easier since there is no movement when scraping.

[0012]

FIG. 1 is a sectional view and FIG. 2 is a plan view of an embodiment of the present invention. In the membrane module 1 shown in FIGS. 1 and 2, the housing includes a lid 2 as a raw water-side housing and a support plate 3 as a permeate-side housing. Lid 2
The support plate 3 and the support plate 3 are both square in plan view, and the cover 2
Has a water inlet 4 and an air port 5, and the support board 3 has a permeated water outlet 6.
Are provided respectively. The lid 2 and the support plate 3 are flat membranes 9
Are fixed to each other by a snap lock 11 while sandwiching the peripheral edge of. A 0-ring 7 is provided on the lid 2 side,
On the side, a flat packing 8 is sandwiched, where it is kept liquid-tight. The mating surface of the support plate 3 with respect to the lid 2 forms the same plane inside and outside the liquid-tight holding portion. The flow path material 10 is laid on the mating surface inside the liquid-tight holding portion of the support board 3 so as to be the same as the mating surface, and the projection 12 is provided at each corner on the outer mating surface. I have. The projection 12 penetrates the flat membrane 9 and fits into a recess provided on the mating surface of the lid 2.

When recovering the concentrate, the membrane module 1 is disassembled. Since the lid 2 and the support board 3 are fixed to each other by the snap lock 11, they are easily disassembled unlike fixing with screws. FIG. 3 shows the disassembled membrane module 1 in a sectional view. When the concentrate 14 is collected, for example, the scraper 13 may be used to scrape the concentrate 14. At this time, since the mating surface of the support plate 3 forms the same plane inside and outside the flat packing 8, the outer surface of the flat packing 8 serves as the escape of the scraper 13. Therefore, the concentrate 14 deposited near the flat packing 8 can be easily scraped by the scraper 13. The flat membrane 9 is firmly fixed to the support board 3 by the projections 12. Therefore, the flat film 9 is scraped by the scraper 13.
The concentrate 14 can be easily collected in the test tube T or the like without being worried.

The type of the flat membrane 9 is not particularly limited. However, when the oocysts of Cryptosporidium are concentrated, M
Use F film or UF film. Preferably, an MF membrane having a pore size of 1 μm or less or a UF membrane having a cut-off molecular weight of 100,000 or more is used. The material of the flat membrane 9 may be cellulose acetate, P
There are TFE, polypropylene, polyolefin, polysulfone and the like. The flow path member 10 is made of a porous or net-like material, and functions to collect permeated water and guide the permeated water to the permeated water outlet 6 while supporting the flat membrane 9 against the liquid pressure on the raw water side. Materials that can be used for the flow path member 10 include polyester, polypropylene, and polyethylene.

FIG. 4 is a flow chart showing the concentration apparatus of the present invention. This concentrating device includes the membrane module 1 shown in FIGS. A raw water tank 16 is provided at the raw water inlet 4 of the membrane module 1, a valve 18 is provided at the air port 5, and a permeated water outlet 6 is provided.
Is connected to a vacuum pump 20 via a three-way valve 19. A suction pipe 21 is also connected to the three-way valve 19. By operating the three-way valve 19, it is possible to select whether the vacuum pump 20 is opened to the permeated water outlet 6 or to the suction pipe 21. FIG. 5 shows a sectional view of the suction pipe 21. The suction pipe 21 is connected to the trap 15
And a tube 25, which are connected to the vacuum pump 20 by a suction line 24.

In order to concentrate raw water with the concentrating device shown in FIG. 4, the following procedure may be used. A specified amount of raw water is put into the raw water tank 16, and the valve 17 is opened. Then, raw water is supplied from the raw water line 22 into the membrane module 1 from the raw water inlet 4. At this time, the valve 18 for opening and closing the air port 5 is opened for a while after the supply is started. This is for eliminating air in the membrane module 1. Next, when the valve 18 is closed and the vacuum pump 20 opened to the permeated water outlet 6 is started,
Raw water is sucked and filtration starts. As the vacuum pump 20, a water ring type is preferably used. Raw water is filtered by the flat membrane 9 and concentrated in the membrane module 1. The permeated water is discharged from the permeated water outlet 6 through the permeation line 23.

After concentrating the specified amount of raw water, the vacuum pump 20 is stopped, all the snap locks 11 are opened, and the lid 2 is removed. The concentrate 14 deposited on the membrane surface of the flat membrane 9 is collected at one place using a scraper 13, and a suction pipe 21 and a vacuum pump 20
After switching the three-way valve 19 so that the opening is established, the vacuum pump 20 is started and the tube 25 of the suction pipe 21 is turned on.
The concentrate is further sucked and collected in the trap 15. The recovered concentrate is directly transferred to the next purification step. In addition, without using the suction pipe 21, as shown in FIG.
By scraping the concentrate with a scraper 13,
It may be transferred to a test tube T. At this time, the scraper 13
The concentrate adhering to is recovered by co-washing with a small amount of sterile water.

The concentrating device shown in FIG. 4 is a device for connecting a vacuum pump 20 to a permeated water line 23 and concentrating it while sucking. A pressurized tank containing raw water is connected to a raw water line 22 and compressed water or the like is used. It may be concentrated while applying pressure.

[0019]

EXAMPLE An attempt was made to concentrate river water using the membrane module 1 shown in FIGS. Then, the time required for concentrating the entire 20 L of raw water and the recoverability of the concentrate were evaluated. The conditions relating to the flat membrane, pressure and the like are as follows. Raw water sample: Tokyo, Arakawa river water (water temperature 12 ℃, turbidity 1
0), 20L flat membrane: UF membrane NTU-3175M (size 300 x 300 mm, effective area 780 cm ² ) manufactured by Nitto Denko Corporation Pressure: 100 Torr (reduced pressure)

As a result, the time required to concentrate 20 L of the raw water was 89 minutes. After the concentration, the concentrate scraped in one place by the scraper and the concentrate attached to the scraper were sucked by the suction pipe 21 in FIG. 5, and the entire amount was collected in a short time.

As a comparative example, a similar evaluation was performed using a commercially available membrane module. The conditions are as follows. Membrane module: Stainless steel filter holder manufactured by Toyo Roshi Co., Ltd. Raw water sample: Arakawa river water, Tokyo (water temperature 18 ° C, turbidity 1
0), 20L flat membrane: UF membrane NTU-3175M (size diameter 293 mm, effective area 530 cm ² ) manufactured by Nitto Denko Corporation Pressure: 100 Torr (reduced pressure)

In the comparative example, the time required to concentrate 20 L of the raw water was 145 minutes. After the concentration, the concentrate was scraped with a scraper. As a result, it was difficult to collect the concentrate attached to the 0-ring and its surroundings, and it was not possible to collect all of the concentrate. Furthermore, when transferring the collected concentrate to a test tube, it was necessary to remove the flat membrane from the membrane module, which was troublesome.

[0023]

According to the membrane module of the present invention and the concentrating apparatus provided with the same, the recovery of the concentrate can be performed quickly without waste, and as a result, the concentration time can be shortened.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a membrane module of the present invention.

FIG. 2 is a plan view showing a membrane module of the present invention.

FIG. 3 is a sectional view showing a disassembled membrane module of the present invention.

FIG. 4 is a flowchart showing a concentrator according to the present invention.

FIG. 5 is a sectional view showing a suction pipe.

FIG. 6 is a cross-sectional view showing a conventional total filtration type membrane module.

[Explanation of symbols]

 1, 26 membrane module 2, 27 lid (raw water side housing) 3, 28 support board (permeate water side housing) 4, 29 raw water inlet 5 air port 6, 30 permeate water outlet 7, 31 O-ring 8 flat packing 9, Reference Signs List 32 flat membrane 10, 33 channel material 11 snap lock 12 projection 13 scraper 14 concentrate 15 trap 16 raw water tank 17 valve 18 valve 19 three-way valve 20 vacuum pump 21 suction pipe 22 raw water line 23 permeated water line 24 suction line 25 tube 34 Screw T test tube

Claims (7)

[Claims] A flat membrane, a raw water-side housing for guiding raw water to the membrane surface of the flat membrane, and a raw membrane-side housing in combination with the raw water-side housing while maintaining liquid tightness in the surface direction of the flat membrane, and holding the periphery of the flat membrane, A permeate-side housing that collects permeate that permeates through the flat membrane, and is fitted with the raw water-side housing through the periphery of the flat membrane.
The membrane module wherein the mating surfaces of the permeate-side housing are flush with each other inside and outside the liquid-tight holding portion. 2. The membrane module according to claim 1, wherein a projection penetrating the flat membrane is provided on a mating surface of the permeated water side housing outside the liquid-tight holding portion. 3. The membrane module according to claim 1, wherein the flat membrane is an MF membrane having a pore size of 1 μm or less. 4. The membrane module according to claim 1, wherein the flat membrane is a UF membrane having a molecular weight cut off of 100000 or more. 5. A concentration apparatus comprising: the membrane module according to claim 1; and a pressure difference generating means serving as a driving source for passing raw water through the flat membrane. 6. The concentrator according to claim 5, wherein said differential pressure generating means is a vacuum pump connected to the permeate-side housing. 7. The vacuum pump is connected to a suction pipe having a trap together with the permeated water side housing,
7. The concentrator according to claim 6, which can be selectively opened.