JP2003190746A - Film element and fresh water generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film element excellent in produceability by decreasing the number of parts constituting the element; and a fresh water generation method using the same. <P>SOLUTION: This film element has a support plate and a film arranged at both sides of the support plate to remove impurities from a liquid and is characterized in that the support plate comprises a flat base plate, frame bodies A which cover the two ends of the base plate facing each other, and frame bodies B which cover the other two ends of the base plate facing each other and are connected to the frame bodies A. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane element and a method for producing water, which are particularly suitable for use in wastewater treatment and water purification treatment.

[0002]

2. Description of the Related Art The membrane separation method is a technique that is widely used while expanding its fields of application because it has characteristics such as energy saving, space saving, labor saving, and product quality improvement.
Membrane separation methods include methods such as reverse osmosis, ultrafiltration, and microfiltration, and membranes in the form of hollow fiber membranes, flat membranes, tubular membranes, etc. are used. This field of application has been used for seawater desalination, water purification, gas separation, blood purification, etc., but recently, from the viewpoint of environmental protection, research has also been applied to apply membrane separation technology to wastewater treatment. It is being advanced.

When the membrane separation technology is applied to wastewater treatment, the membrane module is immersed in a treated water tank filled with wastewater such as activated sludge and the permeate side of the module is sucked by a pump or a water level difference such as a siphon is applied. There is known a technique using an immersion membrane, in which treated water is obtained. At this time,
In activated sludge treatment, aeration is usually performed in order to breed aerobic microorganisms in the aquarium.Therefore, when a membrane module constructed by inserting multiple membrane elements in the aquarium is used for immersion, Thus, solid-liquid separation can be performed while scraping the dirt on the membrane surface of the membrane by the swirling flow formed in the water tank, and operation at a very low cost is possible.

As a submerged type membrane element, a support plate is formed by installing a frame body at the edge of a permeate flow path spacer in JP-A-9-38471 and connecting each frame body with a joint member. However, a structure in which films are provided on both sides of the structure is disclosed. However, this support plate has many constituent parts, and it is necessary to connect each of these parts with an adhesive or the like. Therefore, there is a problem that the manufacturability is poor.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art. By reducing the number of parts constituting the element member, the number of operations for connecting the respective parts is reduced. It is an object of the present invention to provide a membrane element and a water production method capable of improving manufacturability.

[0006]

Means for Solving the Problems The present invention for achieving the above object is a membrane element in which a membrane for removing impurities in a liquid is arranged on both sides of a support plate, and the support plate is a flat substrate. A frame A that covers two opposite ends of the substrate;
It is characterized in that it has a frame body B which covers the other two opposite ends of the substrate and is connected to the frame body A.

Here, a supporting plate covers a plate-shaped substrate and two opposite end portions of the substrate, and a frame A having a permeated water extraction nozzle, the substrate and a frame B covering the frame A. It is preferable that the substrate has a concave-convex plate, and the substrate is a porous plate.

A water-making method in which any one of the above membrane elements is immersed in the liquid to be treated to obtain filtered water from the inside of the membrane element is also preferable, in which case the MLSS concentration is 100.
It is more preferable to obtain filtered water from the liquid to be treated that is 0 mg / liter or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail based on the embodiments shown in the drawings. 1 is a schematic diagram showing an embodiment of the membrane element of the present invention, FIG. 2 is a schematic diagram showing a support plate of the membrane element shown in FIG. 1, and FIG. It is a schematic diagram showing the components which comprise a board, and FIG. 4 is A- of the membrane element shown in FIG.
FIG. 5 is a sectional view taken along the line A ′, and FIG. 5 is a schematic perspective view showing a connecting portion of the support plate shown in FIG. 2.

As shown in FIGS. 1 to 3, the membrane element 1 of the present invention comprises a substrate 3, a frame A4 covering two opposing ends of the substrate 3, and another opposing two of the substrates. It is configured by disposing the membranes 2 on both surfaces of the support plate 11 configured by the frame body B5 that covers one end portion.

The frame body A4 and the frame body B5 are basically shaped so that the substrate 3 can be inserted therein, and are not particularly limited as long as they can be connected to each other. Absent. The frame A4 and the frame B5 can be exemplified by those having a U-shaped cross section as shown in FIGS. 4 and 5.

The frame A4 has such a shape that the frame 7 can be connected to the frame A4 so that the connecting portion 7 is fitted to the inner surface of the frame B5 in order to facilitate connection with the frame B5. For example, as shown in FIG. 5, when the frame body B5 has a U-shaped rail shape, it is preferable that the frame body A4 has a rectangular connecting portion 7 that fits the inner surface dimension of the U-shaped body.

The method of molding the frame A4 is not particularly limited, but in consideration of the fact that it has a U-shaped cross section and the connection portion 7 for connecting to the frame B5 is installed, it can be injection molded. It is preferable to mold because it is inexpensive.

The method for molding the frame B5 is not particularly limited, but a long component having a U-shaped cross section which is fitted at the connection portion 7 with the frame A4 is manufactured by extrusion molding. It is preferable because it is inexpensive.

The fixing method after fitting the frame body A4 and the frame body B5 is not particularly limited, and adhesion by an adhesive, welding by a solvent, welding by ultrasonic welding or the like may be exemplified. it can.

The frame A4 or the frame B5 is preferably provided with a nozzle 6 which communicates with the inside of the membrane element 1 and discharges the internal fluid to the outside of the membrane element 1, but the frame A4 is manufactured by injection molding. In this case, since the nozzle 6 can be manufactured integrally with the frame body A4, it can be preferably installed in the frame body A4. As shown in FIG. 1, the nozzle 6 is installed in a direction parallel to the membrane element 1,
It is possible to exemplify a mode in which each membrane element is installed in the vertical direction and connected by the nozzle 6.

Inside the frame A4 in which the nozzle 6 is installed, there is installed a water collecting passage 9 for collecting filtered water filtered by the membrane 2 around the nozzle 6 and facilitating discharge from the nozzle 6. Preferably (see FIG. 4).

The material of the frame body A4 and the frame body B5 is not particularly limited as long as it has rigidity enough to maintain the shape of the membrane element. For example, metals such as stainless steel, acrylonitrile butadiene styrene rubber (ABS resin), resins such as polyethylene, polypropylene, vinyl chloride and polystyrene, fiber reinforced resin (FR
Composite materials such as P) and other materials can be preferably used.

By arranging the frame A4 around the substrate 3 in this manner, it is possible to easily install the water collecting passage 9 for collecting the filtered water. In addition, by installing the frame B5,
When the membrane 2 is fixed on the support plate 11, the peripheral portion of the support plate, which is the fixed portion, can be made flat by the frame A4 and the frame B5 without a step, and therefore the fixation becomes easy.

After the frame A4 is installed on the substrate 3,
With the structure in which the frame body B5 that covers them is installed, the frame body B5 and the frame body A4 can be directly and strongly bonded.

In the present invention, the membrane 2 is not particularly limited as long as it is porous, but in the case of performing solid-liquid separation of activated sludge water, the pore diameter of the membrane surface is 0.01. It is preferably in the range of about 20 μm. Further, the composition is not particularly limited, polyethylene, polypropylene, polysulfone,
Polyether sulfone, polyvinyl alcohol, cellulose acetate, polyacrylonitrile, chlorinated polyethylene, polyvinylidene fluoride, polyvinyl fluoride, and other materials can be appropriately selected and used. When using in a continuous aeration environment,
Highly durable polyolefin-based and fluorine-based materials can be used particularly preferably, and MLSS (Mixed Liquor)
In the case of relatively clear raw water having a concentration of 1000 mg / liter or less, polyacrylonitrile, cellulose acetate, polysulfone and the like can be particularly preferably used.

The membrane 2 is not particularly limited as to the method of placing it, as long as it is placed on both sides of the support plate 11. For example, a method of fixing the surfaces of the frame A4 and the frame B5 by adhesion with an adhesive or welding by ultrasonic welding,
A method of interposing the film 2 between the inner surfaces of the frame A4 and the frame B5 and the substrate 3 and similarly fixing each material by adhesion by an adhesive or welding by ultrasonic welding can be exemplified.

The substrate 3 is not particularly limited as long as it has a plate shape, but is preferably a porous body because the filtered water filtered by the membrane 2 can be easily introduced to the water collecting passage 9. . As the substrate 3 shown in FIG. 5, a concavo-convex plate having a concavo-convex cross section, a porous plate formed by foaming, a net-like mesh structure plate, and the like can be exemplified.

When the substrate 3 is a concavo-convex plate, it is not particularly limited as long as it has a structure having a plurality of concavities and convexities 8 on both sides. It is preferable that the unevenness 8 is provided so as to form a plurality of grooves arranged in parallel at a constant interval so that the water flows evenly with respect to the film surface. At this time, the pitch of the concavities and convexities 8 is in the range of 1 to 20 mm in order to prevent the film 2 from falling under severe aeration conditions while keeping the amount of filtered water high, and 1.
It is preferably within the range of 5 to 10 mm. Further, the porosity of the substrate 3 due to the concavities and convexities 8 is within the range of 15 to 85% in order to secure a sufficient filtered water flow path and suppress the flow resistance when the filtered water flows while maintaining the strength of the substrate 3. It is preferable. This shows the volume ratio of voids formed by the concavities and convexities 8 when the solid rectangular parallelepiped substrate 3 is taken as 100%. If the void ratio is less than 15%, the flow resistance becomes large and the filtered water is efficiently supplied. If water cannot be taken and exceeds 85%, the strength of the support plate is significantly reduced.

Similarly, in the case of a porous plate, it is preferable that it has a large number of holes of 5 mm or less so that the film does not fall, and the porosity is also preferably in the range of 15 to 85%.

The material of the substrate 3 is not particularly limited as long as the material has a tensile strength of about 15 MPa or more in D638 according to the ASTM test method.
Metals such as stainless steel, acrylonitrile butadiene styrene rubber (ABS resin), polyethylene, polypropylene, vinyl chloride and other resins, fiber reinforced resin (FR
Composite materials such as P) and other materials can be preferably used.

Further, a non-woven fabric is provided between the substrate 3 and the film 2.
When a net, a porous film, or the like is installed, the fall of the film can be further suppressed, so that it can be preferably used.

In the membrane element 1 constructed as described above, the filtered water filtered by the membrane 2 flows to the irregularities 8 inside the substrate 3, and then is collected in the water collecting passage 9 and finally the nozzle. It is discharged from 6 to the outside of the membrane element 1.

A plurality of the membrane elements 1 are housed in a housing so that a plurality of the membrane elements 1 are parallel to each other and a space is formed between the membrane surfaces of the membrane 2 to form a membrane module. For example, as shown in FIG. 6, this membrane module is used by being provided so as to be immersed in water to be treated such as organic wastewater stored in the water tank 22 to be treated. Inside the membrane module 21, a plurality of membrane elements 1 loaded vertically are provided, and a blower 2 is provided below the membrane elements 1.
An air diffuser 23 that supplies the gas from the membrane 4 to the membrane surface of the membrane is provided, and a pump 25 that sucks filtered water is provided downstream of the membrane module 21.

In the filtration device thus constructed,
Water to be treated such as wastewater is generated by the suction force of the pump 25 from the membrane 2.
Pass through. At this time, suspended substances such as microbial particles and inorganic particles contained in the water to be treated are filtered. And
The water that has passed through the membrane 2 flows inside the substrate 3 and the water collecting channel 9
After being collected in the water, it is taken out of the treated water tank 22 through the nozzle 6. On the other hand, in parallel with filtration, the air diffuser 2
3 generates bubbles, and an ascending flow parallel to the membrane surface of the membrane element 1 caused by the air lift action of the bubbles causes the filtered material deposited on the membrane surface to separate.

The membrane module 21 of the present invention has a MLSS (Mixed Liquor and
When filtering the water to be treated having a Suspended Solids concentration of 1000 mg / liter or more, it has a high removability of the filtered material by bubbles and can be used particularly preferably.

[0032]

[Example] <Example 1> Height 1500 mm x width 480 m
In a rectangular parallelepiped having a thickness of 4 mm and a thickness of 4 mm, a concave portion having a depth of 2 mm and a width of 2 mm is provided at a pitch of 5 mm so that the porosity is 70%.
The non-woven fabric of No. 3 was welded and adhered on the upper surface of the substrate 3. After that, the frame body B4 (inside dimension of cross section 4 × 15 mm) having a U-shaped cross section at the left and right edges of the substrate 3 provided with the nonwoven fabric, and the U-shaped cross section at the upper and lower edges of the substrate 3, When the substrate is fitted to the part, a rectangular water collecting channel 9 as shown in FIG. 4 is formed,
Moreover, it has a nozzle 6 communicating with the water collection channel 9, and has a frame B5.
Connection part 7 (outer size 4 × 15 × 25m)
The support plate 11 was configured by fitting the frame A4 having the m) in the positional relationship shown in FIGS. 2 and 5. Next, the membrane 2 was adhered and fixed on the surfaces of the frame A4 and the frame B5 on both sides of the support plate 11 to manufacture the membrane element 1 having the dimensions of 1540 mm height × 500 mm width × 7 mm thickness shown in FIG. The membrane is
The average pore size of the surface that exhibits filtration performance is 0.1 μm,
A material having a water permeability of 40 × 10 ⁻⁹ m ³ / m ² / Pa / s was used.

The method of manufacturing the support plate 11 of the membrane element 1 is as follows. First, the frame body A4 is fitted into the U-shaped portion of the frame body A4 so as to cover the upper and lower edges of the substrate 3, and then the connecting portion of the frame body A4. Adhesive was applied to the whole 7 and the frame body B5 was fitted so as to cover the connection portion of the frame body A4 and the substrate 3. Frame B5
By fitting the outer surface of the connecting portion 7 and the inner surface of the frame body B5 when fitting, the frame body A4 and the frame body B5 could be easily positioned. Further, since the adhesive is applied only to the connecting portion 7, the support plate 11 can be manufactured in a short time, and the amount of the adhesive used can be suppressed to the necessary minimum.

[0034]

The membrane element 1 of the present invention comprises a frame A which covers two opposite ends of a substrate, and a frame A which covers the other two opposite ends of the substrate and is connected to the frame A. Since the membrane is installed on both sides of the support plate having B, the number of parts constituting the membrane element 1 can be reduced and each part can be easily positioned, so that the manufacturability of the membrane element 1 is improved. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the membrane element of the present invention.

FIG. 2 is a schematic diagram showing a support plate of the membrane element shown in FIG.

FIG. 3 is a schematic view showing components that form the support plate of FIG.

4 is a cross-sectional view taken along the line AA ′ of the membrane element shown in FIG.

5 is a schematic perspective view showing a connecting portion of the support plate shown in FIG.

FIG. 6 is a schematic flow chart showing one embodiment of the water production method of the present invention.

[Explanation of symbols]

1 ... Membrane element 2 ... Membrane 3 ... Board 4 ... Frame A 5: Frame B 6 ... Nozzle 7 ...... Connection part 8 ... unevenness 9 …… Catchment channel 11 ... Support plate 21 ... Membrane module 22 ... Treated water tank 23 ... Air diffuser 24 …… Blower 25 …… Pump

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D006 GA02 HA43 HA93 JA04A                       JA08A JA08C JA14A JA19A                       JA53A KA44 KB22 MA03                       MC18 MC22 MC23 MC26 MC27                       MC28 MC29 MC33 MC39 MC62                       PB08 PC62

Claims (6)

[Claims] 1. A membrane element in which a film for removing impurities in a liquid is provided on both surfaces of a support plate, wherein the support plate covers a flat plate-shaped substrate and two opposing end portions of the substrate. A membrane element comprising A and a frame body B which covers the other two opposite ends of the substrate and is connected to the frame body A. 2. The support plate, a plate-shaped substrate, a frame A that covers two opposite ends of the substrate and has a permeated water extraction nozzle, and a frame that covers the substrate and the frame A. The membrane element according to claim 1, which has a body B. 3. The membrane element according to claim 1, wherein the substrate is an uneven plate. 4. The membrane element according to claim 1, wherein the substrate is a porous plate. 5. A method for producing water, comprising immersing the membrane element according to claim 1 in a liquid to be treated to obtain permeated water from the inside of the membrane element. 6. The method for producing water according to claim 5, wherein the concentration of the liquid to be treated is 1000 mg / liter or more.