JP2003053370A - Dynamic filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological treating reaction tank in which a separation membrane is hardly clogged. SOLUTION: The biological treating reaction tank 2 is provided with a supply pipe 3 to supply raw water 6 to the reaction tank 2. An air distributing device 4 for the biological treatment is disposed in one end side of the reaction tank 2 in the raw water 6. A blower 5 disposed outside the reaction tank 2 is connected to the air distributing device 4 and air is sent by the blower 5 via the air distributing device 4 into the reaction tank 2. A membrane separator 7 is immersed in the raw water 6 in the other end of the reaction tank 2 and a discharge pipe 8 is connected to the upper part of the membrane separator 7. A water suction pump 9 is connected to the discharge pipe 8. An air distributing device 10 for cleaning is connected to the lower part of the membrane separator 7 and is provided with a blower 11. As for the membrane separator 7, a metal mesh having openings in a mesh state is used for the separation membrane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic filtration device which allows water in a biological treatment reaction tank to permeate using a dynamic filter.

[0002]

2. Description of the Related Art In the treatment of activated sludge such as sewage, night soil and industrial wastewater, there is dynamic filtration using a separation membrane having permeation holes of several tens to several hundreds of μm as a solid-liquid separation technique for sludge and the like. In the present technology, a dynamic layer (cake layer) is formed on the surface of a filtration membrane material by activated sludge, and this is used as a filtration layer. FIG. 6 shows a conventional dynamic filtration device 50 using the same. The biological treatment reaction tank 51 of this filtration device 50 is provided with a supply pipe 53 for supplying the raw water 52 accumulated in this tank, and inside the reaction tank 51, an air diffuser 54 is arranged at one end side thereof. is doing. A blower 55 arranged outside the reaction tank 51 is connected to the air diffuser 54. A membrane separator 57 is disposed on the other end side inside the reaction tank 51.
A discharge pipe 58 is connected to the lower part of the. FIG. 7 is an enlarged schematic view of the membrane separator 57 shown in FIG. Membrane separator 5
7 is a plurality of filters 59 arranged at a predetermined interval.
The filter 59 comprises an element frame 60 as a frame material.
A non-woven fabric 61 is attached to the bottom of which the discharge ports 62 of the filter 59 are gathered and connected to the discharge pipe 58.

The biological treatment reaction tank 51 diffuses the aerated air supplied by the blower into the raw water 52 of the air diffuser, and supplies the oxygen necessary for the activated sludge treatment by the aeration. The raw water 52 that is about to flow into the membrane separator 57 passes through the nonwoven fabric 61 of the membrane separator 57 due to the water pressure difference caused by the difference in height between the water surface and the discharge pipe 58, and the permeated water is
It is discharged to the outside of the reaction tank 51 through the discharge port 62 and the discharge pipe 58. In addition, a stable filtration performance of the membrane separator 57 is obtained by forming a dynamic layer of activated sludge particles on the surface of the non-woven fabric 61 to a thickness necessary for filtration in a stable manner.

[0004]

The above-mentioned membrane separator of the dynamic filtration device uses a non-woven fabric (non-woven fabric) as a membrane material, and the non-woven fabric has a pore size with a variation of several tens to several hundreds of μm. It plays a role of stably maintaining the dynamic layer on the surface of the non-woven fabric. Further, the non-woven fabric has a laminated structure in which fibers are three-dimensionally and intricately entangled. Therefore, solid matters such as sludge enter not only the surface of the cloth but also the spaces between the fibers inside the cloth. Usually, during filtration, solid substances such as sludge gradually accumulate on the surface of the membrane due to filtration, and clogging occurs. Therefore, it is necessary to periodically pour water from the permeate side to the raw water side (backwashing) with respect to the membrane separator. However, in the case of a non-woven fabric in which solids have entered the inside of the cloth, the clogged solid substance cannot be discharged to the outside of the cloth system even if it is backwashed, and the filtration performance cannot be recovered by washing, and the non-woven fabric must be replaced. There is a problem that the number of times increases and the membrane replacement cost increases.

The present invention has been made in view of the above circumstances, and it is difficult for a filtration membrane used in a membrane separator to be clogged, and even if it is clogged, it is possible to easily remove the clogged solid matter. An object of the present invention is to provide a dynamic filtration device equipped with a membrane separator that can be used for a long period of time.

[0006]

In order to achieve the above object, a dynamic filtration device of the present invention comprises a biological treatment reaction tank and a membrane separator which allows treated water in the reaction tank to permeate through a membrane material. In the provided dynamic filtration device, a mesh-shaped and single-layer wire mesh is adopted as the membrane material of the membrane separator. Further, in order to achieve the above object, the dynamic filtration device of the present invention is a dynamic filtration device comprising a biological treatment reaction tank and a membrane separator that allows treated water in the reaction tank to permeate through a membrane material. The reason is that the wire mesh is adopted as the membrane material of the membrane separator and the air diffuser for aerating the gas is provided directly below the membrane separator. In this dynamic filtration device, an air diffuser for biological treatment can be provided in a place other than directly below the membrane separator in the biological reaction tank, and each aspirator can be independently aerated. Further, in the above-mentioned invention, in the cleaning step of the membrane separator, in addition to cleaning by air bubbling from an air diffuser installed immediately below the membrane separator, backwashing using treated water, etc., backwashing with air is also performed. be able to. Furthermore, the above invention, the treated water that has passed through the membrane separator,
It is possible to provide a means for sucking from the upper part of the membrane separator using a suction pump and controlling the permeation flow rate of the permeate to be constant. Furthermore, a cleaning remover can be installed on the wire mesh of the membrane separator, and the cake tank adhered to the surface of the wire mesh can be scraped off by the cleaning remover for cleaning.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a dynamic filtration device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a dynamic filtration device 1 according to the invention. The dynamic filtration device 1 includes a biological treatment reaction tank 2 and a membrane separator 7 inside thereof. The biological treatment reaction tank 2 is provided with a supply pipe 3 for supplying raw water 6 such as sewage, night soil and industrial wastewater into the reaction tank 2. Inside the reaction tank 2, an air diffuser for biological treatment is provided at one end side. 4 are arranged.
The air diffuser 4 has a blower 5 arranged outside the reaction tank 2.
Is connected, and the blower 5 can send air to the raw water 6 in the reaction tank 2 through the air diffuser 4.

A membrane separator 7 is immersed in the raw water 6 at the other end of the reaction tank 2, and a discharge pipe 8 is connected to the upper portion of the membrane separator 7. A water absorption pump 9 is connected to the discharge pipe 8 so that the permeated water can be discharged from the membrane separator 7 to the outside of the reaction tank 2. Below the membrane separator 7, a cleaning air diffuser 1 is provided.
0 is arranged at a distance from the membrane separator 7, a blower 11 is arranged in the air diffuser 10, and the blower 11 can send air to the raw water 6 in the reaction tank 2.

2 and 3 are enlarged views of the membrane separator 7. A plurality of filters 12a to 12e (these filters are collectively referred to as 12) are arranged side by side in parallel with each other in the longitudinal direction at intervals in the horizontal direction. The filter 12 is a movable shaft 1 as a connecting member.
The movable side filters 12a, 12c and 12e of the first, third and fifth rows are integrally attached from above in the figure through 6, and the fixed side filters 12b and 12d of the second and fourth rows are integrally mounted. , But they are integrally attached separately. A scraping spatula 18 is provided at the right end of one of the filters 12a, 12c, 12e, and a scraping spatula 19 is also provided at the left end of the other filter 12b, 12d. The parts are the separation membranes 1 of the filters 12 that face (adjacent) each.
It comes in contact with 5.

The movable filters 12a, 12c, 12e are connected to a drive unit 17 via a movable shaft 16, and when the drive unit 17 is driven, the filters 12a, 12c, 1e.
2e moves horizontally via the movable shaft 16 and slides the tips of the scrapers 18 and 19 on the surface of the separation membrane 15 of the filter 12. Movable filter 12a, 12c, 12e
Is connected to the drainage passage 20a on one side, and the fixed side filter 1
2b and 12d are connected to the drainage passage 20b on the other side, and the drainage passages 20a and 20b are connected to the drain pipe 8. The arrow in the figure indicates the flow of the raw water 6 permeating into the filter 12.

FIG. 4 is an enlarged view of the filter 12 used in the membrane separator 7, and FIG. 5 is a horizontal sectional view thereof. In the filter 12 having a rectangular parallelepiped outer shape, a stainless wire mesh 15 as a permeable membrane material is attached around the element frame 14 as a frame material by welding or interlocking. The wire net 15 has substantially uniform mesh holes each having a side of several tens to several hundreds of μm, and is arranged in a single layer (one sheet) on the surface of the rectangular element frame 14. Filter 1
In the production of No. 2, since the wire mesh 15 is hard, a supporting plate for supporting the non-woven fabric is not required, and the membrane separator 7
The connection port of the exhaust pipe 8 can also be directly attached to the wire net 15 without the need for a support plate or the like. Further, since the element frame 14 can be made small (or omitted), it has an effect of increasing the surface area of the separation membrane.

Next, the operation of the dynamic filtration device 1 according to this embodiment will be described. The filter device 1 aerates the aerated air supplied into the reaction tank 2 by the blowers 5 and 11 into the raw water 6 through the air diffuser, and supplies oxygen necessary for the activated sludge treatment. The wire mesh 15 of the filter 12 stably maintains a dynamic layer composed of suspended particles of activated sludge at a sufficient thickness necessary for filtration. Then, the inside of the membrane separator 7 is decompressed by the operation of the water absorption pump 9, and the raw water 6
While separating the solid matter contained in the wire mesh 15 as a separation membrane, the raw raw water 6 is treated inside the wire mesh 15, that is, the filter 1
2. Since the wire net 15 has a mesh-like two-dimensional planar shape, it is difficult for floating molecules to enter the mesh of the wire net 15. This is different in that the non-woven fabric has a three-dimensional structure and is held in a three-dimensional mesh and permanently fixed to the part. The treated raw water 6 that has passed through the wire net 15 of the filter 12 is discharged to the outside of the reaction tank 2 by the water suction pump 9. The water suction pump 9 discharges the treated raw water 6 discharged using a pressure gauge or the like with a constant amount of permeated water. Since the discharge pipe 8 is provided above the membrane separator 7 (filter 12), in the filter 12, the raw treated water 6 flows out from the lower side to the upper side.

In the case of backwashing, the blower 11 is driven at the same time when water is flown backward from the discharge pipe 8 and the air diffuser 10 for washing is used.
As a result, the lower part of the membrane separator 7 is aerated, so that when the adhesion layer on the surface of the wire netting 15 is peeled off, bubbling due to aeration plays a role of promoting the peeling. Since the non-woven fabric has a mesh of three-dimensional shape in a complicated direction as described above, it is difficult to remove the solid matter only by backwashing in one direction. On the other hand, in the wire mesh 15 structure of the present filter 12, when backwashing, since it is a single layer structure of the wire mesh, the fluid is unidirectionally flowed from the inside to the outside of the wire mesh to remove the clogged solid matter. It can be peeled off and the deposit can be removed more easily than that.

When the dynamic layer is thickened by using the membrane separator 7 for a long period of time or when the wire net 15 is washed when other deposits are attached, the membrane separator 7 is driven. The device 17 is operated to bring the filters 12a, 12c, 12e located in the normal state shown in FIG. 4 into the movable state shown in FIG. 5, and the tip portions of the scrapers 18, 19 slide on the surface of the wire mesh 15. By doing so, the deposit can be scraped off.

As described above, in the present embodiment, since the one-layer metal net 15 having the mesh-like uniform holes is used as the membrane separating material of the membrane separator 7, it is difficult for the suspended matter to enter the holes of the metal mesh 15. Further, even if the mesh of the wire netting 15 is closed, since it is a single layer, it is possible to easily remove the adhered solid matter by backwashing. Further, in the present embodiment, since stainless steel which is not easily corroded is used as the material of the wire net 15, the wire net 15 has excellent durability, and the film quality of the wire net 15 can be kept high for a long period of time, and the replacement cost is reduced. be able to.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications and changes can be made based on the technical idea of the present invention. For example, in the above-described embodiment, the metal wire mesh 15 made of stainless steel is used for the membrane separator 7, but any other material may be used as long as it is a single-layer material that is resistant to corrosion. In addition, in order to remove deposits on the surface of the wire net 15, a scraper 18,
Although 19 is used, other removing tools such as a brush may be used instead of the scraper. The length of the mesh of the wire net 15 is uniform or substantially uniform.
Two or more different mesh sizes may be used within the range of 00 μm.

[0017]

As described above, according to the dynamic filtration device of the present invention, the dynamic filtration provided with the biological treatment reaction tank and the membrane separator for allowing the treated water in the reaction tank to permeate through the membrane material. In the device, a mesh-shaped and single-layer wire mesh was adopted as the membrane material of the membrane separator. Therefore, by using a wire net having a single-layer structure as the dynamic filtration device, the sludge adhered during backwashing can be easily peeled off, and the recovery of filtration performance by washing becomes better than that when a non-woven fabric or the like is used. Furthermore, the non-woven fabric is weak in strength,
Although the frequency of replacement is high, the wire mesh has excellent durability and the number of times of replacement is reduced, resulting in cost reduction.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a dynamic filtration device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a static (normal) state of a membrane separator arranged in the dynamic filtration device of FIG.

3 is a schematic plan view of a movable state of a membrane separator arranged in the dynamic filtration device of FIG. 1. FIG.

FIG. 4 is an enlarged view of a filter of the dynamic filtration device of FIG.

5 is an enlarged cross-sectional view of a filter of the dynamic filtration device of FIG.

FIG. 6 is a schematic sectional view of a conventional dynamic filtration device.

FIG. 7 is a schematic side view of the membrane separator of the dynamic filtration device of FIG.

[Explanation of symbols]

1 Dynamic filtration device 2 Biological treatment reaction tank 3 supply pipes 4 Air diffuser for biological treatment 5,11 blower 7 Membrane separator 8 discharge pipe 9 Water absorption pump 10 Air diffuser for cleaning 12, 12a-12e Filter 14 element frame 15 Wire mesh (separation membrane) 16 movable axes 17 Drive 18,19 Scratch spatula 20a, 20b drainage path

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 37/02 B01D 29/38 520E 39/12 530E 550C 580F (72) Inventor Katsumi Nagami, Kanagawa Prefecture 12 Nishiki-cho, Yokohama Mitsubishi Heavy Industries Co., Ltd.Yokohama Works (72) Inventor Kazuhiko Fujise 12 Nishiki-cho, Naka-ku, Yokohama-shi Kanagawa Mitsubishi Heavy Industries, Ltd. Yokohama Works F-term (reference) 4D019 AA03 BA02 BB02 4D028 AB00 BC17 CA00 4D066 BA01 BB02 CA13 FA03 FA06

Claims (6)

[Claims] 1. A dynamic filtration device comprising a biological treatment reaction tank and a membrane separator that allows treated water in the reaction tank to permeate through the membrane material, wherein the membrane material of the membrane separator is mesh-shaped and A dynamic filtration device featuring a single-layer wire mesh. 2. In a dynamic filtration device equipped with a biological treatment reaction tank and a membrane separator that allows treated water in the reaction tank to pass through the membrane material, a wire mesh is used as the membrane material of the membrane separator. A dynamic filtration device characterized in that an air diffuser for aeration of gas is provided directly below the membrane separator. 3. In the biological reaction tank, an air diffuser for biological treatment is provided in a place other than directly below the membrane separator, and each air diffuser can be independently aerated. The dynamic filtration device according to claim 2. 4. In the step of cleaning the membrane separator, in addition to cleaning by air bubbling from an air diffuser installed immediately below the membrane separator and backwashing with treated water, backwashing with air is also performed. The dynamic filtration device according to any one of claims 1 to 3. 5. A means for sucking the treated water that has permeated the inside of the membrane separator from the upper part of the membrane separator by using a suction pump and controlling the permeation flow rate of the permeated liquid to be constant is provided. The dynamic filtration device according to any one of claims 1 to 4. 6. A cleaning remover is installed on the wire mesh of the membrane separator, and the cake tank attached to the surface of the wire mesh is scraped off by the cleaning remover for cleaning. The dynamic filtration device according to any one of 1.