JP2000237551A - Immersion type flat membrane separation device and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an immersion type flat membrane separation device capable of continuing filtering over a long period of time while efficiently removing a cake on the membrane surface without damage to the membrane. SOLUTION: A separation body unit A is constituted by fitting a filter membrane 12 on the both surfaces of a water permeable material 16 by interposing a spacer 14, fitting membrane end fixing materials 20 and 22 in the parallel direction of its upper and lower ends respectively and also forming a hollow part at the upper part membrane end fixing materials 20, and a water collecting part is constituted by fixing the left and right end parts of a plurality of these separation body units with each other at membrane joining and fixing parts 24 and 26 and fixing a water collecting pipe 24a allowing the hollow part of the upper part membrane end fixing material to communicate with the upper part of the joining and fixing part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an immersion type flat membrane separation apparatus and a control method thereof, and more particularly to an immersion type membrane separation apparatus capable of efficiently separating suspended matter in wastewater by a microfiltration membrane or an ultrafiltration membrane. The present invention relates to an apparatus and a control method thereof.

[0002]

2. Description of the Related Art Recently, with the development of technology, not only solid-liquid separation of pharmaceutical and food production lines, but also water production,
It is widely applied to the recovery of organic matter from wastewater, solid-liquid separation of clean water, sewage and human waste, and even to sewage and industrial wastewater treatment. As an inexpensive running cost method applicable to wastewater treatment, an immersion method has been developed in which a filtration membrane is immersed in a stock solution tank and the total amount is filtered. In this method, instead of not providing the flow of the undiluted solution on the membrane surface, filtration is performed with a lower transmembrane pressure than in the liquid circulation system, thereby suppressing the accumulation of cake on the membrane surface and performing filtration. There is an advantage that it can be driven by power and its maintenance is easy because of its simple structure. In this immersion method, in order to generate a pressure difference between the membranes for filtration, a suction method is often used because there is less clogging than in the pressure method, and it is only necessary to immerse the filtration membrane in a stock solution tank. I have. In this suction method, the cake adhering to the film surface is separated and removed by bubbling while supplying air from a diffuser tube or a diffuser plate provided below the film.

[0003] The shape of the membrane used includes a tubular membrane, a hollow fiber membrane and a flat membrane. Of these, the tubular membrane is not suitable for large-scale processing because a large membrane area cannot be secured. Further, the hollow fiber membrane has a high volumetric efficiency,
As shown in Japanese Patent Publication No. 128 and the like, filtration resistance increases due to suspension adhered or fixed inside the bundle of hollow fiber membranes, and it is difficult to remove these suspensions by air bubbling. It is.

[0004] On the other hand, a flat membrane does not adhere locally to a suspension unlike a hollow fiber membrane, so that the membrane surface can be easily cleaned by air bubbling and has a higher volumetric efficiency than a tubular membrane. From such a viewpoint, it is desirable to apply a flat membrane to the immersion-type filtration system for filtering a liquid having a high suspension concentration.

[0005]

However, when a flat membrane is used, there is a case where the removal or peeling of the cake on the membrane surface by air bubbling from below the filtration membrane is not sufficient. There is a problem that a film area is required, which leads to an increase in cost. As a method for coping with this, a plurality of filtration membranes are immersed in a separation tank and erected, as disclosed in JP-A-6-327949.
In some cases, a string-shaped flexible cleaning body is provided between the membranes. In this method, the flexible cleaning body comes into contact with the membrane surface to peel off extraneous matter by air bubbling from below.
Inefficient due to uneven contact. In addition, when the filtration is stopped and the air bubbling is continued, air accumulation occurs at the upper part of the membrane, the filtration membrane swells, and the adjacent filtration membranes may rub against each other to damage the membrane surface. Thus, cleaning by air bubbling still has a problem to be improved.

[0006] The present invention has been made in view of such circumstances, and solves the problems of the prior art, while efficiently removing the cake on the membrane surface, without long-term filtration without damage to the filtration membrane. It is an object of the present invention to provide an immersion type flat membrane separation apparatus that can be continued and a control method thereof.

[0007]

According to the present invention, in order to achieve the above object, in the immersion type flat membrane separation apparatus according to claim 1 of the present invention, filtration membranes are provided on both surfaces of a water-permeable material, Separator units are constructed by attaching the membrane end fixing materials horizontally at the upper and lower ends, and a plurality of these separator units are arranged side by side at intervals, and the left and right ends of these separator units are fixed by membrane bonding. In addition to the fixing with a material, a suction pipe is provided in the membrane bonding fixing material, and the suction pipe is communicated with a water passage of the water-permeable material.

According to the immersion type flat membrane separation device of the present invention,
The wastewater in the stock solution tank is sucked from the entire filtration membrane into the water-permeable material,
The treated water is purified by the filtration membrane, and the treated water is discharged to the outside through the water passage of the water-permeable material and the suction pipe. The air is also discharged to the outside together with the treated water. The contact between the filtration membranes due to the swelling of the upper part is eliminated, and damage to the filtration membranes can be prevented.

Further, in the immersion type flat membrane separation apparatus according to claim 2 of the present invention, in the first aspect, each of the upper and lower membrane end fixing members is provided with one inter-membrane holding member for maintaining a distance between the respective separator units. More than one. ADVANTAGE OF THE INVENTION According to the immersion type flat membrane separation apparatus of this invention, since the space | interval between membranes is maintained, there is no contact between filtration membranes and damage of filtration membranes can be prevented.

Further, in the immersion type flat membrane separation device according to claim 3 of the present invention, in claim 1 or 2, a drain pipe communicating with a water passage of the separator unit is provided. ADVANTAGE OF THE INVENTION According to the immersion type flat membrane separation apparatus of this invention, when raising an apparatus on a water surface, the swelling of the lower part of a membrane by the treatment water staying in a water-permeable material is prevented, and thereby contact between filtration membranes is prevented. And damage to the filtration membrane can be prevented.

According to a fourth aspect of the present invention, there is provided the immersion type flat membrane separation device according to the first, second or third aspect, further comprising an air diffuser disposed below the separator unit and communicating with the air diffuser. The air introduction pipe thus set is installed along the membrane bonding fixing material. According to the immersion type flat membrane separation device of the present invention, when the separator unit is taken out of the raw water tank, the diffuser tube and the air introduction tube can also be taken out integrally, and workability is improved.

According to a fifth aspect of the present invention, there is provided the method for controlling a submerged flat membrane separation device according to the first, second, third, or fourth aspect, wherein the filtration is temporarily stopped within a predetermined time when the filtration is stopped. It is characterized by filtering over time. ADVANTAGE OF THE INVENTION According to the immersion type flat membrane separation apparatus of this invention, even if filtration is stopped for a long time, there is no possibility that the upper part of a membrane may swell. Therefore, there is no contact between filtration membranes, and damage to the filtration membrane can be prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a submerged flat membrane separation apparatus and a control method thereof according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a submerged flat membrane separation apparatus according to the present invention. In the immersion type flat membrane separation device 10, the filtration membrane 12 covers the water-permeable material 16 via the spacer 14. The spacer 14 is formed of a breathable material such as a nonwoven fabric. in this case,
The filtration membrane 12 and the spacer 14 may have an integral structure. As shown in FIG. 2, the water-permeable material 16 is a base material 1 having a corrugated cross section.
6a, a perforated plate 16b is attached to both sides of the base material 16a.
a and the perforated plate 16b define a plurality of independent water passages 18 extending in the height direction. Further, the water-permeable material 16 may be a porous body. At the upper and lower ends of the filtration membrane 12, membrane end fixing materials 20 and 22 are provided in the horizontal direction, respectively, and the upper membrane end fixing material 20 is hollow as shown in FIG. The hollow portion 20a of the upper membrane end fixing member 20 is communicated with a suction tube described later. In this embodiment, the lower end fixing member 22 is not hollow.

A plurality of sets of the separation unit A composed of the filtration membrane 12, the spacer 14, the water-permeable material 16, the membrane end fixing materials 20, 22 and the like thus formed are juxtaposed with each other, and the left and right sides thereof are arranged. Membrane bonding fixing materials 24 and 26 are provided at the ends. The membrane bonding fixing members 24, 26
a, 26a, and the water collecting pipes 24a, 26a communicate with the hollow portion 20a of the upper membrane end fixing material 20. Suction pipes 28 and 30 are formed at the upper ends of the water collecting pipes 24a and 26a. The upper and lower membrane edge fixing members 20 and 22 of each of the separator units A are provided with a comb-shaped inter-membrane holding member 3.
2 and 34 are provided at least one each, and the teeth of the inter-membrane holding members 32 and 34 are interposed between the separator units A and A, and the inter-membrane spacing is uniformly maintained. In the membrane separation device 10, the device 10 is immersed in a stock solution tank, and the suction pipes 28 and 30 are connected to a suction hose such as a vacuum pump to suck the fluid of the water collection pipes 24a and 26a, and the separation unit A Filter while aerating air from underneath. Then, a pressure difference is generated between both surfaces of the filtration membrane 12, and the pressure difference causes the drainage in the stock solution tank to flow through the filtration membrane 1.
2, the water is sucked into the water passage 18 through the spacer 14 and the through hole 16c of the perforated plate 16b, and from the water passage 18 through the hollow portion 20a of the upper membrane end fixing material 20, the water collecting pipe 24a of the membrane bonding fixing material 24, 26; It is sucked by 26a and discharged to the outside via suction pipes 28 and 30.

Therefore, in the above-mentioned immersion type flat membrane separation apparatus, since the drainage is sucked from the entire surface of the filtration membrane 12 and the air can be uniformly supplied between the membranes, the membrane performance can be maintained for a long period of time. When air accumulates in the hollow portion 20a of the upper membrane end fixing material 20, the air is transferred to the membrane bonding fixing material 2
Since the suction is performed by the water collecting pipes 24a and 26a of the fourth and fourth water collection tubes 24, the upper portion of the filtration membrane 12 does not swell, and the filtration membrane 12 is not damaged due to the rubbing between the filtration membranes 12. However, if you stop filtration, along with the downtime,
Air accumulates in the upper part of the filtration membrane 12. If the filtration is stopped for a predetermined time, for example, 6 hours or more, the amount of air accumulation increases, and the filtration membrane 12 may swell. Therefore, suction filtration is temporarily performed within 6 hours for a short time, for example, 1 minute or more. Thus, the swelling of the filtration membrane 12 can be prevented, and damage to the filtration membrane 12 can be prevented.

FIG. 3 shows another embodiment of the present invention, in which a hollow membrane end fixing member 22 is provided at a lower portion, and water collecting pipes 24b, 26b are provided on membrane bonding fixing members 24, 26, respectively. A, drain pipes 36, 38 are provided in the water collecting pipes 24b, 26b, and the hollow portion of the membrane end fixing member 22 communicates with the water collecting pipes 24b, 26b. Caps 40 and 42 are attached to the drain pipes 36 and 38, respectively, and the drain pipes 36 and 38 are closed.
Then, when the apparatus 10 is lifted above the water surface, the caps 40 and 42 are removed, the drain pipes 36 and 38 are opened, and the treated water is discharged from the separator unit A to prevent the swelling of the filtration membrane 12 due to the treated water. To prevent. It should be noted that, in place of the caps 40 and 42, a check valve (not shown) is interposed between the drain pipes 36 and 38, and when the pressure inside the separator unit A is lower than the pressure of the stock solution tank, the drain pipes 36 and 38 When the pressure in the separator unit A becomes higher than the pressure of the stock solution tank, the drain pipes 36 and 38 may be opened. In this case, the caps 40, 42
The drain pipes 36 and 38 are automatically opened when the apparatus is pulled up from the stock solution tank, without the need for removing the device.

In this embodiment, the water-permeable material 16 and the filtration membrane 12 are integrated by point bonding, so that the filtration membrane 1
2, the stress concentration is dispersed and the reliability is improved. FIG. 4 shows still another embodiment of the present invention, in which a diffuser 44 is provided along each filtration membrane 12 below each separator unit A, and a membrane bonding fixing material 24, The air introduction pipes 46 and 48 are provided in the water collection pipe 24.
a, 26a are installed independently of the suction pipes 28, 30. The air introduction pipes 46 and 48 are provided at their lower ends with branch pipes 46a and 48a installed over the respective separator units A, and communicate the branch pipes 46a and 48a to the respective diffuser pipes 44. Thereby, air can be reliably supplied to the filtration membrane 12 of each separation unit A.

FIG. 5 shows still another embodiment of the present invention, in which the separator units A, A shown in FIG. While connecting the suction pipes 28, 28, 30, 30 to each other,
A diffuser 44 is provided below the lower separator unit A,
Air introduction pipes 46 and 48 communicated with the end of the air diffusion pipe 44.
Are disposed in the membrane bonding fixing members 24 and 26, and they are extended outward from the upper surface of the upper separation unit A.

In the separator unit A in each of the above embodiments, the water passage 18 is formed in the vertical direction (see FIG. 2). However, as shown in FIG. 6, the water passage 18 may be formed in the horizontal direction. Good. In this case, the drainage in the stock solution tank is
2. The suction pipes 28, 30 provided through the holes of the perforated plate 16b of the water passage material 16 into the horizontally disposed water passages 18 and disposed in the membrane bonding fixing members 24, 26 from the water passages 18 are removed. Is discharged to the outside. In this case, the membrane bonding fixing members 24 and 26 can be directly used as suction tubes without providing the suction tubes 28 and 30. At that time, as shown in FIG.
The portion of the upper part of the perforated plate 16b where the through holes are not opened is the resin 50
To keep it sealed.

[0020]

As described above, in the immersion type flat membrane separation apparatus according to the first aspect of the present invention, filtration membranes are provided on both surfaces of the water-permeable material, and the membrane ends are fixed horizontally at the upper and lower ends. Each of the materials is attached to form a separation unit, the plurality of separation units are juxtaposed at intervals, and the left and right ends of the separation units are fixed with a membrane bonding fixing material,
A suction pipe is provided on the membrane-bonded fixing material, and the suction pipe is connected to a water passage of the water-permeable material. Therefore, the wastewater in the undiluted solution tank is sucked into the water-permeable material from the entire filtration membrane, purified by the filtration membrane, and the treated water is discharged to the outside through the water-flow passage of the water-permeable material and the suction pipe. At this time, since the air is also discharged to the outside together with the treated water, the air does not accumulate at the upper part of the membrane, and the filtration membranes do not come into contact with each other due to the swelling of the upper part of the membrane, thereby preventing damage to the filtration membrane.

Further, in the immersion type flat membrane separation apparatus according to claim 2 of the present invention, in the first aspect, each of the upper and lower membrane edge fixing members is provided with one inter-membrane holding member for maintaining a distance between the respective separator units. More than one. Therefore, since the interval between the membranes is maintained, the contact between the filtration membranes is eliminated, and damage to the filtration membranes can be prevented. Further, in the immersion type flat membrane separation device of claim 3 according to the present invention, in claim 1 or 2, a drain pipe communicating with a water passage of the separator unit is provided. Therefore, when the apparatus is raised above the water surface, the swelling of the lower part of the membrane due to the treated water staying in the water-permeable material is prevented, thereby eliminating the contact between the filtration membranes,
Damage to the filtration membrane can be prevented.

Further, in the immersion type flat membrane separation device according to claim 4 of the present invention, in claim 1, 2, or 3, an air diffuser is provided below the separator unit and communicates with the air diffuser. The air introduction pipe thus set is installed along the membrane bonding fixing material. Therefore, when the separator unit is taken out of the raw water tank, the diffuser tube and the air introduction tube can also be taken out integrally, and workability is improved.

According to a fifth aspect of the present invention, in the control method of the immersion type flat membrane separation apparatus, the apparatus according to any one of the first, second, third, and fourth aspects is characterized in that the filtration is temporarily stopped within a predetermined time when the filtration is stopped. It is characterized by filtering over time. Therefore, even when the filtration is stopped for a long time, there is no possibility that the upper portion of the membrane will swell, so that there is no contact between the filtration membranes, and damage to the filtration membrane can be prevented.

[Brief description of the drawings]

FIG. 1 is a conceptual partially cutaway perspective view showing an embodiment of an immersion type flat membrane separation device according to the present invention.

FIG. 2 is a cutaway perspective view showing a part of the structure of a submerged flat membrane separation device according to the present invention.

FIG. 3 is a conceptual partially cutaway perspective view showing another embodiment of the immersion type flat membrane separation device according to the present invention.

FIG. 4 is a conceptual partially cutaway perspective view showing still another embodiment of the immersion type flat membrane separation device according to the present invention.

FIG. 5 is a conceptual perspective view showing still another embodiment of the immersion type flat membrane separation device according to the present invention.

FIG. 6 is a cutaway perspective view showing a part of the structure of still another embodiment of the immersion type flat membrane separation device according to the present invention.

FIG. 7 shows still another embodiment of the immersion type flat membrane separation device according to the present invention, in which a part of a structure in which a membrane bonding fixing material is directly used as a suction tube without providing a suction tube. Notched perspective view shown

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Immersion type flat membrane separation apparatus 12 ... Filtration membrane 14 ... Spacer 16 ... Water-permeable material 16a ... Substrate 16b ... Perforated plate 16c ... Through-hole 18 ... Water-passage 20, 22 ... Membrane end fixing material 20a ... Hollow part 24, 26: membrane bonding and fixing material 24a, 26a: water collecting pipe 28, 30 ... suction pipe 32, 34 ... intermembrane holding material 36, 38 ... drain part 40, 42 ... cap 44 ... diffuser pipe 46, 48 ... air introduction pipe 46a, 48a ... Branch pipe

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masato Onishi 1-1-1 Uchikanda, Chiyoda-ku, Tokyo Inside Hitachi Plant Construction Co., Ltd. (72) Toshio Yamadera 1-1-1 Uchikanda, Chiyoda-ku, Tokyo No. 14 Hitachi Plant Construction Co., Ltd. (72) Inventor Hiroshi Okuno 1-1-14 Uchikanda, Chiyoda-ku, Tokyo (72) Inside Hitachi Plant Construction Co., Ltd. (72) Inventor Yukio Murai 1 Uchikanda, Chiyoda-ku, Tokyo No. 1-114 Hitachi Plant Construction Co., Ltd. (72) Inventor Hiroki Ando 1-11-1 Uchikanda, Chiyoda-ku, Tokyo Inside Hitachi Plant Construction Co., Ltd. (72) Inventor Shirou Tanso Takatsuki-shi, Osaka 6-6 Josai-cho Inside Your Sako Corporation (72) Inventor Nobuo Hayashi 6-6 Josai-cho, Takatsuki-shi, Osaka F term (reference) 4D006 GA06 GA07 HA48 HA93 JA03A JA06A JA08A JA19A JA20A JA22A JA27A JA31A JA71 KA44 KC14 KE24Q MA03 PB08 PB15

Claims (5)

[Claims] 1. Separation units are constructed by attaching filtration membranes to both sides of a water-permeable material, and attaching a membrane end fixing material horizontally at upper and lower ends thereof to form a separation unit. The left and right ends of these separator units are fixed with a membrane bonding fixing material, and a suction pipe is arranged in the membrane bonding fixing material, and the suction pipe communicates with the water passage of the water flow material. An immersion type flat membrane separation device characterized by having been performed. 2. The immersion-type flat membrane separation apparatus according to claim 1, wherein one or more intermembrane holding members for maintaining an interval between the respective separator units are provided on the upper and lower membrane edge fixing members. . 3. A drain pipe communicating with a water passage of the separator unit.
2. The immersion type flat membrane separation device according to 1.). 4. An air diffusion tube is provided below the separator unit, and an air introduction tube communicating with the air diffusion tube is installed along the membrane bonding fixing material. 4. The immersion type flat membrane separation device according to 2 or 3. 5. A control method for an immersion type flat membrane separation apparatus according to claim 1, wherein the filtration is temporarily carried out for a short time within a predetermined time when the filtration is stopped.