JP2000246018A - Flat membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the water collecting properties and the reverse cleaning properties of permeating water and maintain stable filter capability over a long period of time by arranging a passage material consisting of a tubular material with perforations which allow passage of liquid below the membrane face of a nonwoven fabric. SOLUTION: The flat membrane element 10 is constituted of plural nonwoven fabrics 12, 13 and plural passage materials 15 arranged below the membrane face of the nonwoven fabrics 12, 13. In this case, the rest of this constitution is not particularly defined and the plural passage materials 15 can be structurally fitted to a support frame 20 consisting of plural long-size members 21-24. Each of the passage materials 15 is formed of a hollow tubular material through which permeating water and reverse cleaning water pass. In addition, the passage materials 15 are arranged at an interval so that each passage material is perpendicular with the flow direction of liquid to be treated. Further, each of the passage materials 15 has perforations 16 for allowing passage of the liquid such as the permeating water or the reverse cleaning water. The end part of each passage material 15 is connected, in a comb-tooth fashion, to a water collecting passage 30 formed in the long-size member 21, and one of the ends of the water collecting passage 30 is made to protrude, as a permeating water nozzle 31 to the outside of the flat membrane element 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat membrane element having excellent water collection and backwashing performance of permeated water.

[0002]

2. Description of the Related Art As a membrane module used for solid-liquid separation of activated sludge liquid or the like, a module in which a plurality of flat membrane elements are housed in a housing is used. As the flat membrane element, an element in which a spacer serving as a permeate flow path material is sandwiched inside a flat membrane made of two nonwoven fabrics, a permeate nozzle is attached, and the periphery of the flat membrane is adhered is used. .

When the operation of the membrane module is continued, sludge or the like excessively adheres to the nonwoven fabric membrane surface of the flat membrane element to reduce the filtration capacity. It is necessary to send in and backwash the nonwoven fabric membrane surface. However, since many nonwoven fabric membranes have a large pore size, the pressure loss during back washing is large, and it is difficult to uniformly wash the entire membrane surface. Therefore, since the recovery of the filtration ability by the backwashing is not sufficient, in order to maintain the filtration ability, the flat membrane element must be taken out from the housing and washed. In addition, a mesh member for collecting permeated water is inserted between the two flat membranes. However, in this method, the permeated water is not sufficiently collected, and when the membrane area becomes large, The tendency becomes stronger.

[0004] It is an object of the present invention to provide a flat membrane element which is excellent in water collection and backwashing performance of permeated water and can maintain a stable filtration ability for a long period of time.

[0005]

SUMMARY OF THE INVENTION The present invention provides a flat membrane element in which a passage member made of a tube having a hole through which a liquid can enter and exit is arranged below the surface of the nonwoven fabric membrane. The present invention also provides a flat membrane element in which a support frame and a passage member formed integrally with the support frame and formed of a tube material having a hole through which liquid can enter and exit are arranged below a nonwoven fabric membrane surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flat membrane element according to the present invention will be described below with reference to FIGS. FIG. 1 is a front view of one embodiment of the flat membrane element of the present invention, FIG. 2 is a front view of another embodiment of the flat membrane element of the present invention, and FIG. FIG. 3 is a view corresponding to a cross-sectional view in the width direction of the flat membrane element in FIG. 1 or a view corresponding to a cross-sectional view in the length direction of the flat membrane element in FIG. 2 (however, a membrane portion is omitted). 1 and 2, the nonwoven fabric film on one side is partially cut out for convenience of explanation.

The flat membrane element 10 comprises a nonwoven fabric membrane 12, 1
The other configuration is not particularly limited as long as a required number of passage members 15 made of a tube material are arranged below the membrane surface of No. 3, and as shown in FIG. 1, the long members 21, 22, 23 and A structure in which a plurality of passage members 15 are attached to a support frame 20 composed of 24 can be employed.

The passage member 15 is formed of a hollow tube so that permeated water and backwash water can pass through the inside thereof. The thickness, length, and cross-sectional shape (circular, various polygons, etc.) of the tube are as follows. It is set as appropriate according to the size of the flat membrane element 10 and the filtering ability.

A plurality of passage members 15 are disposed at intervals so as to be perpendicular to the flow direction of the liquid to be treated (the direction of the arrow in FIG. 1) when the housing member is loaded into the housing and the filtration operation is performed. This arrangement interval is preferably from 5 to 100 mm, and more preferably from 20 to 50 mm.

The passage member 15 has a hole 16 through which liquid such as permeated water and backwash water can enter and exit. These holes 1
6 adjusts the size, the formation part and the number so that the permeated water can be sucked in and the backwash water can be jetted. At the time of washing,
A gas such as air may be used instead of the washing water. Hole 1
Considering the absorption of permeated water and the injection pressure of back washing, the size of 6 is preferably 0.1 to 3 mm, more preferably 0.5 to 1.5 mm when the shape of the hole is circular. When the hole has another shape, the size is adjusted to be substantially the same as the case of a circular shape.

One end of each passage member 15 is connected to one of the water collecting passages 30 formed inside the long member 21 at right angles in a comb-teeth shape. Nozzle 3
1 protrudes outside the flat membrane element 10.
Here, it is preferable that at least a portion where the water collecting passage 30 is formed is made of a transparent material so that the flow of the permeated water can be confirmed in the long member 21. When the flat membrane element 10 is loaded in the housing, the permeated water discharge pipe formed of a plastic tube or the like is connected to the permeated water nozzle 31.

The flat membrane element 10 has a flat membrane 1
The periphery of each of 2 and 13 is a long member 21 of the support frame 20.
24 to 24 are fixed by an adhesive or the like. However, when the long member 21 having the water collecting passage 30 is made transparent, the nonwoven fabric membranes 12 and 13 are formed as shown in FIG. It is preferable not to cover up. Therefore, in such a case, as shown in FIG. 1, it is preferable that the long member 21 be wider than the other long members 22 to 24.

The nonwoven fabrics constituting the flat membranes 12 and 13 include, for example, natural fibers such as cotton, hemp and wool, polyester, polystyrene, polyvinyl chloride, polyvinylidene chloride, poly (meth) acrylate, viscose rayon. , Cellulose acetate, cellulose derivatives such as methylcellulose, polyolefins such as polyethylene and polypropylene, polycarbonates, polyamides, polyesteramides, polyethers, polyimides, polyamideimides, polyetherimides and mixtures or copolymers of two or more thereof. Those obtained from fibers by a conventional method can be used. Examples of such a nonwoven fabric are MF180 (trade name: polyester fiber nonwoven fabric having a fiber diameter of 10 μm; manufactured by Japan Vilene Co., Ltd.), trade name: SB-3
5 (a polyester fiber non-woven fabric having a fiber diameter of 10 μm; manufactured by Unitika), trade name FC3105 (a polyester fiber non-woven fabric having a fiber diameter of 10 μm; manufactured by Japan Vilene), NF felt (a polyester fiber non-woven cloth having a fiber diameter of 10 μm; Japan) Felt), trade name FC302 (non-woven fabric made of polyester fiber having a fiber diameter of 10 μm; manufactured by Japan Vilene), trade name S-030 (woven fabric made of polypropylene fiber having a fiber diameter of 10 μm; manufactured by Japan Vilene), trade name H8007 (fiber Polyester fiber nonwoven fabric having a diameter of 10 μm; manufactured by Nippon Vilene Co., Ltd.).

The flat membrane element 10 comprises a nonwoven fabric membrane 12, 1
A spacer made of a mesh-like member serving as a flow path holding material may be interposed between 3 and the passage member 15.

The flat membrane element 10 comprises a nonwoven fabric membrane 12, 1
3 may be attached to the support frame 20 so as to be detachable. As a method of making it detachable, the periphery of each of the nonwoven fabric films 12 and 13 is pressed with a pressing plate,
In addition to a method in which the holding plate and the support frame 20 are fastened with a fastener such as a clamp or a bolt and a nut, a method in which the nonwoven fabric films 12 and 13 are sandwiched around the support frame 20 and a groove that can be pressed is formed. (For example, groove 3 in FIG. 3
2 is formed around the support frame 20). The material of the support frame 20 is not particularly limited. However, in order to form a groove having the above-described action, the whole or the groove can be made of an elastic material such as rubber, a plastic plate, or a sheet metal. When the groove is formed of an inelastic body,
The nonwoven fabric and the holding member may be inserted into the groove together and fixed.

As described above, in the flat membrane element 10, the nonwoven fabric membranes 12 and 13 are detachably attached,
Compared to the case where an adhesive is used, the support frame 20, the passage material 1
5 makes it easy to remove the nonwoven fabric films 12 and 13 from the
It is preferable because the support frame 20 and the passage member 15 can be easily reused.

The basic structure of the flat membrane element 10 shown in FIG. 2 is the same as that of the flat membrane element 10 shown in FIG. 1, and the passage member 15 is loaded in the housing and the flow direction of the liquid to be treated when the filtration operation is performed. (The direction of the arrow in FIG. 2) is different only in that a plurality of them are arranged at intervals so as to be parallel with each other.

Further, as another embodiment, as a passage material 15
May be arranged in a lattice shape, the arrangement direction of the passage material 15 may be inclined, or the arrangement direction of some may be different.

Next, the operation when the flat membrane element 10 shown in FIG. 1 is loaded in a housing as a membrane module and a filtration operation is performed will be described. Non-woven fabric membrane 12, 1 by filtration operation
The permeated water filtered by the filter 3 is sucked through the hole 16 of the passage member 15, collected in the water collecting passage 30, and the permeated water nozzle 31
It is discharged from the discharge pipe connected to. On the other hand, at the time of back washing, washing water or air sent from the permeated water nozzle 31 and sent to the passage member 15 through the water collecting passage 30 is jetted from the hole 16 at an appropriate pressure. Due to such back washing, pressure is applied uniformly over the entire nonwoven fabric films 12 and 13, so that the entire film surface is uniformly and reliably washed.

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Embodiment 1 In a flat membrane element 10 having a front shape as shown in FIG. 1 in which passage members 15 are arranged at intervals of 30 mm, a nonwoven fabric membrane H
Using 8007 (manufactured by Japan Vilene Co., Ltd.), a 1.4 mm thick polyethylene net (manufactured by Dainippon Plastics Co., Ltd., Netron D6) is inserted between the passage material 15 and the nonwoven fabric membrane 12 to form an end around the nonwoven fabric membrane 12. Was sealed with a urethane adhesive (manufactured by Nippon Polyurethane Co., Ltd., main agent Coronate 4403, curing agent Nipporan 4235). The effective area of the membrane was 0.05 m ² . This flat membrane element 10 is ML
Soak in activated sludge liquid of SS10000mg / L, 1m
The filtration operation was performed at a water permeation rate of / day. The filtration pressure at the start of filtration was 0.5 kPa, but after 30 minutes, the filtration pressure was 5 kPa.
Pa. Here, 14 ml for 10 seconds from the permeated water nozzle 31 through the passage material 15 into the nonwoven fabric membrane 12.
The permeated water was sent at a rate of / sec to wash the nonwoven fabric membrane 12.
When the operation was started again, the filtration pressure was restored to 0.5 kPa. The same reverse washing was repeated every 30 minutes of the filtration operation, and the filtration operation was performed for a total of 24 hours. After the elapse of 24 hours, the filtration pressure after back washing was 1 kPa.

Embodiment 2 In the flat membrane element 10 having the front shape as shown in FIG. 1 and the cross-sectional shape as shown in FIG. 3 in which the passage members 15 are arranged at intervals of 30 mm, the thickness is set so as to sandwich the passage members 15 from both sides. 1.4mm polyethylene net (Netron D
6) and the nonwoven fabric film H8007 are arranged in this order,
The periphery of the net and the membrane 12 was inserted into the groove 32 together with a long plate material (pressing material) and fixed. The effective area of the membrane is 0.
05 m ² . This flat membrane element 10 is MLSS
Immerse in 10000mg / L activated sludge solution, 1m / d
The filtration operation was performed at the water permeation rate of ay. The filtration pressure at the start of filtration was 0.5 kPa, but after 30 minutes, the filtration pressure was 5 kPa.
Rose. Here, the passage material 15 is moved from the permeated water nozzle 31 to the passage material 15.
14 ml / s for 10 seconds through the nonwoven fabric membrane 12
At ec, permeated water was sent to wash the nonwoven fabric membrane 12. When the operation was started again, the filtration pressure was restored to 0.5 kPa.
The same back washing was repeated every 30 minutes of the filtration operation, and a total of 24
Time filtration operation was performed. After the elapse of 24 hours, the filtration pressure after back washing was 0.5 kPa. Further, the suspended solid (SS) of the permeated water immediately after the start of the filtration was 40 mg / L, but it became 10 mg / L or less after 3 minutes, and there was no problem in the fixed state of the nonwoven fabric membrane 12.

COMPARATIVE EXAMPLE 1 A nonwoven fabric membrane H8007 having no passage material 15 and a flat membrane element consisting of only a 1.4 mm thick polyethylene net (Netron D6) serving as a flow channel holding material (the effective area of the membrane is 0.1 mm). 05M ²⁾ using, example 1 and was subjected to filtration operation under the same conditions, the filtration pressure at the start of filtration is was 1 kPa, filtration pressure immediately after backwash after 2 hours 15k
Pa.

[0024]

According to the flat membrane element of the present invention, since a plurality of passage members having holes are arranged between the nonwoven fabric membranes, the permeated water can be smoothly collected and discharged regardless of the size of the flat membrane element. You. Further, at the time of back washing, since washing water or the like is sprayed from the holes of the passage material, the entire nonwoven fabric surface can be uniformly and reliably washed. Therefore, stable filtration ability can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a front view of one embodiment of a flat membrane element of the present invention.

FIG. 2 is a front view of another embodiment of the flat membrane element of the present invention.

3 corresponds to a cross-sectional view in a width direction of the flat membrane element in FIG. 1 or a cross-sectional view in a length direction of the flat membrane element in FIG. 2 in another embodiment of the flat membrane element of the present invention. It is a figure (however, a film part is omitted).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flat membrane element 12, 13 Nonwoven fabric membrane 15 Passage material 16 Hole 20 Support frame 21-24 Long member 30 Water collecting passage 31 Permeated water nozzle 32 Groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toyozo Hamada 2-5-45-201, Rikyumae-cho, Suma-ku, Kobe-shi, Hyogo Prefecture (72) Inventor Osamu Nakatsuka 79-11- 306

Claims (7)

[Claims] 1. A flat membrane element in which a passage member made of a tube having a hole through which a liquid can enter and exit is arranged below the nonwoven fabric membrane surface. 2. A flat membrane element in which a support frame and a passage member formed integrally with the support frame and formed of a tube material having a hole through which liquid can enter and exit are arranged below a nonwoven fabric membrane surface. 3. A plurality of passage members are arranged at intervals so as to be perpendicular or parallel to the flow of the liquid to be treated.
Or the flat membrane element according to 2. 4. The flat membrane element according to claim 1, wherein the diameter of the hole of the passage material through which liquid can enter and exit is 0.1 to 3 mm. 5. The water collecting passage according to claim 1, wherein ends of the plurality of passage materials are connected to one water collecting passage, and a part of the water collecting passage protrudes outside the flat membrane element. Flat membrane element. 6. The flat membrane element according to claim 1, further comprising a spacer formed of a mesh member between the nonwoven fabric membrane and the passage material. 7. The flat membrane element according to claim 2, wherein the nonwoven fabric is detachably attached to the support frame.