JP2002102661A - Solid-liquid separation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-liquid separation apparatus capable of stably carrying out solid-liquid separation by a separation membrane for a long duration while preventing clogging of an aeration apparatus. SOLUTION: The solid-liquid separation apparatus (11) is provided with a membrane separation apparatus (2) installed in the inside of a membrane separation tank (1) and an aeration apparatus (3) installed under the membrane separation apparatus (2) in approximately horizontal direction. The aeration apparatus (3) is provided with aeration pipes (5) each having a tip end opening part 7 at the tip end part and a slit-like opening part (8) extended in the side part in the longitudinal direction. The aeration pipes (5) and an aeration header pipe (10) are connected through a gas supply pipe (9) having a higher ventilation resistance than that of the aeration pipes (5). The aeration header pipe (10) has a larger cross-section than that of the aeration pipes (5) and is positioned higher than the liquid level of the object liquid to be treated in the membrane separation tank (1). The aeration is kept well and even and the pressure balance among the aeration pipes (5) is kept constant by the aeration apparatus (3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-liquid separation apparatus for performing solid-liquid separation using a separation membrane in water treatment and the like. The present invention relates to a solid-liquid separation device capable of performing the following.

[0002]

2. Description of the Related Art Conventionally, sand filtration, gravity sedimentation, and the like have been used as methods for performing solid-liquid separation of water to be treated having high turbidity, such as water purification treatment, sewage treatment, and industrial wastewater treatment.
However, the solid-liquid separation by these methods has the disadvantage that the quality of the treated water to be obtained may be insufficient, and that a large site is required for the solid-liquid separation.

[0003] As a method of solving such inconvenience,
In recent years, various methods for performing solid-liquid separation of water to be treated using a membrane module provided with a separation membrane such as a microfiltration membrane or an ultrafiltration membrane have been studied. When the treatment of the water to be treated is performed using the separation membrane, treated water having high water quality can be obtained.

When the solid-liquid separation of the water to be treated is performed using this separation membrane, suspended solids (SS
(1), the clogging of the separation membrane proceeds, so that the filtration flow rate decreases or the transmembrane pressure increases. In order to recover from such a state, an air diffuser is provided below the membrane module, and air is diffused during execution of filtration or while filtration is stopped. Solid-liquid separation is performed while preventing deposition on the film surface. The air diffuser generally uses a tube body provided with a gas discharge hole in an air diffuser made of metal, resin, or the like, and is often formed of members having the same diameter because of easy production.

[0005] However, the gas discharge holes of the air diffuser are clogged due to long-term use, making it difficult to uniformly apply air bubbles to the separation membrane of the membrane module. Occurs. For this reason, there has been a problem that stable solid-liquid separation processing cannot be performed.

An example of the air diffuser for solving such a problem is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-108549. The air diffuser disclosed in this publication has a large-diameter tubular body formed by bending an intermediate portion to have a long length, and an inner diameter of 6-1.
A plurality of air diffusion tubes each having a small diameter of 5 mm and having different lengths are arranged in parallel inside the large diameter tube, and a filler is filled between the large diameter tube and the air diffusion tube. And are integrally formed. The distal end of each diffuser tube is protruded from the large-diameter pipe, and the inside of the diffuser tube forms a pipe-shaped ventilation path.

[0007] The air diffuser is disposed inside a box-shaped air diffuser case that is open at the top and bottom, and is immersed in a liquid to be processed in a processing tank and is arranged below the membrane cartridge. In the membrane cartridge, a plurality of flat membrane cartridges are arranged in parallel in a box-shaped membrane case also opened at the top and bottom. The air diffuser is connected to a blower disposed above the water surface in the treatment tank, the base end side of the air diffuser, the tip of the air diffuser at the same water depth position in the membrane case, the membrane The openings are opened at an equal distance from each other in a direction intersecting with the film surface of the cartridge.

According to this conventional air diffuser, the air supplied from the blower is ejected at substantially the same speed from the gas discharge holes formed at the distal end of each air diffuser, and rises substantially at the same distance. It is stated that the membrane cartridges are supplied to a plurality of rows of membrane cartridges at an appropriate speed without bias, and the membrane surface is evenly washed by a gas-liquid mixed ascending flow containing bubbles.

[0009]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 9-108.
The air diffuser disclosed in Japanese Patent No. 549 does not provide a small-diameter gas discharge hole in the middle of the air diffuser as described above.
A plurality of diffuser pipes of different lengths are juxtaposed, and the opening at the distal end of the pipe-shaped ventilation passage in the diffuser pipe is used as a gas discharge hole. However, when trying to arrange the gas discharge holes uniformly over the entire separation membrane of the membrane cartridge, the length of the air passage changes, so that it is difficult to balance the pressure between the air diffusers, and the air diffuses unevenly. There is a problem that it is easy to become.

One of the causes of the clogging of the gas discharge holes is that the pressure balance between the gas discharge holes is lost due to a slight inclination or the like at the time of installation of the device, and the gas discharge holes are diffused from the gas discharge holes. The liquid to be treated that has entered inside is dried by air,
The dry matter is to close the gas discharge holes. This phenomenon is particularly noticeable when the air diffuser is stopped due to a failure of the air diffuser or when the air diffuser is not required, for example, because the liquid to be treated flows back into the air diffuser.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to prevent the air diffuser from being closed and to perform a solid-liquid separation process using a separation membrane stably for a long period of time. It is intended to provide a device.

[0012]

The invention according to claim 1 of the present invention is directed to a membrane separation device provided inside a membrane separation tank, and an air diffuser provided below the membrane separation device. A solid-liquid separation device comprising: a diffuser, which is provided with a diffuser tube extending in a substantially horizontal direction and having a gas discharge unit;
The solid-liquid separation device is characterized by being connected to an air supply source through an air supply pipe having a larger ventilation resistance than the air diffusion pipe.

According to the present invention, an air diffuser arranged substantially horizontally below the membrane separation device is connected to an air supply source via an air supply tube having a larger airflow resistance than the air diffuser. The air from the air supply source is pressure-fed to the air diffuser by the air supply tube, and is diffused at a high pressure from the gas discharge portion of the air diffuser. The diffused air bubbles pass through the liquid to be treated, reach the membrane separation device, pass through the vicinity of the membrane surface of the membrane separation device, and are discharged onto the water surface. When the bubbles rise to the surface of the water through the liquid to be treated, an upward gas-liquid mixed flow of the liquid to be treated and the bubbles is generated. The gas-liquid mixed flow and the bubbles scrub the membrane surface of the membrane separation device to prevent the suspended substance from adhering to the membrane surface and prevent the membrane surface from being clogged.

[0014] The invention according to claim 2 specifies that the air diffusion tube is connected to the air diffusion header tube via the air supply tube. According to the present invention, the air from the air supply source is stored and filled in the air diffusion header tube. For example, when air from the air supply source is supplied to the plurality of air diffusers in parallel via a branched air supply tube, the air becomes a high flow rate through each air supply tube branched from the air diffusion header tube. The gas is discharged to each diffuser at a high pressure, and is uniformly diffused from the gas discharge portion of each diffuser. The pressure balance between each diffuser tube is kept constant, and the uniformity of the diffuser is ensured.

According to a third aspect of the present invention, as a preferred embodiment of the air diffusion device, the air diffusion tube has an opening at a tip end thereof and is 30 ° above a horizontal plane passing through a center line of the air diffusion tube. Stipulates that a slit-shaped opening is provided in a lower portion that does not exceed the angle.

The air diffuser has an opening at the tip,
A slit-shaped opening is also provided in a lower portion that does not exceed an angle of 30 ° above a horizontal plane passing through the center line, and is disposed substantially horizontally below the membrane separation device. Since the slit-shaped opening is not arranged at the upper part of the air diffuser, the gas supplied to the inside is discharged from the entire slit and rises inside the liquid, while always being present up to the tip inside the air diffuser. When the slit-shaped opening is provided above the horizontal plane passing through the center line of the air diffuser and at an angle exceeding 30 °, gas is supplied to the slit-shaped opening near the connection between the air supply pipe and the air diffuser. Since it is discharged from the part, it does not spread to the entire diffuser tube, and uniformity of diffuser cannot be maintained.

For this reason, it is necessary to provide the air diffusion tube below a horizontal plane passing through the center line of the air diffusion tube. In particular, it is preferable that the slit-shaped opening is provided in a horizontal plane portion which does not exceed 30 ° above a horizontal plane passing through the center line and passes through the center line.

According to the present invention, in addition to the uniform gas diffusion performed by the gas discharge portion including the front end opening and the slit-shaped opening, the liquid to be treated that has flowed back into the diffuser tube and entered the inside of the diffuser tube Is easily pushed out of the opening at the tip. Suspended solids dried in the air diffuser can stably diffuse air for a long period of time without blocking the gas discharge unit.

According to the present invention, the width of the slit-shaped opening is 1 to 10 mm and the length thereof is 30 to 20 mm.
0 mm. If the width of the slit-shaped opening is too short, the liquid to be treated that has entered the air diffuser from the slit-shaped opening may be dried by air and clogged by the solid content. On the other hand, if the width is too wide, it is difficult to diffuse air uniformly over the whole.
For this reason, the width of the slit-shaped opening is 1 to 10
mm.

On the other hand, if the length of the slit-shaped opening is too short, the range in which air can diffuse is narrowed, and it is difficult to ensure uniformity of air diffusion. On the other hand, if the length of the slit-shaped opening is too long. It is difficult to diffuse air uniformly throughout.
For this reason, the length of the slit-shaped opening is 30 to 200.
mm.

The slit-shaped opening may be provided so as to intersect with the longitudinal direction of the air diffuser or may be provided obliquely. Satisfactorily can be maintained. Also,
The number of the slits is not particularly limited, but it is most preferable that only one slit is provided along the longitudinal direction of the air diffuser. Similarly, the slit shape is not particularly limited, and may be an arbitrary shape such as a linear shape or a waveform.

The invention according to claim 5 stipulates that the cross-sectional area of the air diffuser is 7 to 2000 mm ² . If the thickness of the air diffuser is too small, the pressure loss increases, and it becomes difficult to supply a required flow of gas. In addition, there is a possibility that the gas discharge unit may be closed. On the other hand, if the air diffuser is too thick, the pressure balance at the gas discharge portion is likely to be lost, and there is a possibility that air cannot be diffused uniformly. The cross-sectional shape of the air diffuser may be circular, elliptical, polygonal, or the like, and its cross-sectional area is preferably 7 to 2000 mm ² ,
More preferably, it is ²⁰ to 500 mm ² .

According to a sixth aspect of the present invention, the diffuser header tube has a sectional area larger than a sectional area of the diffuser tube. The cross-sectional area of the trachea is 60 times the cross-sectional area of the diffuser header tube.
% Or less.

In order to maintain a constant pressure balance between the respective diffuser tubes, it is necessary to connect the diffuser header tube and the diffuser tube via an air supply tube having a larger ventilation resistance than the diffuser tube. preferable. At this time, the cross-sectional area of the diffuser header tube is preferably larger than the cross-sectional area of the diffuser tube in order to keep the pressure balance constant, and the cross-sectional area of the diffuser header tube is smaller than the cross-sectional area of the diffuser header tube. More preferably, it is 60% or less. The cross-sectional shape of the diffuser header tube can be any shape such as a circle, an ellipse, and a polygon.

In the invention according to claim 8, the diffuser header tube is arranged at a position higher than the liquid level of the liquid to be treated in the membrane separation tank. According to the present invention, by providing the diffuser header tube at a position higher than the water level of the liquid to be treated, it is possible to prevent the liquid to be treated from entering the diffuser header tube when the supply of air is stopped. be able to.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a solid-liquid separation device showing an example of a typical embodiment of the present invention. In FIG. 1, a solid-liquid separation device 11 according to an example of the present embodiment is disposed substantially horizontally below a membrane separation device 2 disposed inside a membrane separation tank 1 and the same. And an air diffuser 3.

The membrane separation device 2 has a plurality of membrane modules (not shown) disposed inside a substantially rectangular casing having at least an open top and bottom. The air diffuser 3 includes an air diffuser 5 having a gas discharge port 6 at a lower portion of a pipe made of metal, resin, or the like. A blower 4 serving as an air supply source disposed outside the apparatus of the membrane separation tank 1 through an air supply pipe 9 having a larger airflow resistance than the air diffusion pipe 5 is provided at one end of the air diffusion pipe 5.
Is connected.

As the membrane module used in the present invention,
A conventionally well-known separation membrane having a shape such as a flat membrane type, a hollow fiber membrane type, a tubular membrane type, and a bag-like membrane type can be applied. Various materials such as cellulose, polyolefin, polysulfone, polyvinyl alcohol, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, and ceramics can be used as the material. In particular, a polyolefin-based material such as polyethylene or polypropylene having high strength and elongation, which is excellent in workability and responsiveness to shaking during aeration, is preferred.

The pore size of the membrane used in the present invention is not particularly limited, and the pore size is generally 0.001 to 0.1 μm generally called an ultrafiltration membrane, or the pore size generally called a microfiltration membrane. It is possible to use a material having a fine pore size of 0.1 to 1 μm or more, which is selected according to the particle size of the substance to be subjected to solid-liquid separation. For example, if it is used for solid-liquid separation of activated sludge, the pore size is preferably 0.5 μm or less, and if sterilization is required as in the filtration of purified water, the pore size is 0.1 μm or less. Is preferred.

As a method of operating the membrane separation device 2, a well-known immersion suction filtration method, a gravity filtration method using a head difference and the like, which have been widely known, are used. Now, blower 4
When air is supplied into the air diffuser 5 of the air diffuser 3,
The air from the blower 4 is sent under pressure to the air diffuser 5 via the air supply pipe 9 and is uniformly diffused from the gas discharge port 6 of the air diffuser 5. The gas bubbles diffused from the gas discharge port 6 reach the membrane separation device 2 through the water to be treated, and further pass near the membrane surface of the membrane module and are discharged onto the water surface.

At this time, since the bubbles move above the water surface through the liquid to be treated, an upward gas-liquid mixed flow composed of the liquid to be treated and the bubbles is generated. The bubbles and the gas-liquid mixed flow scrub the membrane surface of the membrane module, thereby preventing the suspended solids from adhering to the membrane surface and preventing rapid clogging of the membrane surface.

Since the membrane separation device 2 has a conventionally well-known structure, a detailed description thereof will be omitted here, and the structure of the air diffusion device 3 which is a feature of the present invention will be specifically described. I do.

FIGS. 2 and 3 show the air diffuser 3 according to the present invention.
FIG. 2 is a perspective view showing a main part of the air diffusing device 3, and FIG. 3 is a schematic view showing an example of the air diffusing device 3.

In these figures, the air diffuser 3
The gas diffuser 5 has an open end at both ends, and the gas diffuser 5 has a distal end opening 7 at its distal end and a gas discharge portion having a slit-shaped opening 8 over its longitudinal direction. I have. The slit-like opening 8 is disposed below a horizontal plane passing through the center line of the air diffuser 5. The diffuser tube 5 is disposed below the membrane separation device 2 and is arranged substantially horizontally, and is connected to the diffuser header tube 10 via an air supply tube 9 having a larger airflow resistance than the diffuser tube 5.

By providing such a structure, in addition to the uniform air diffusion by the front end opening 7 and the slit-shaped opening 8, the front end is opened.
The liquid to be treated that has entered the inside of the air diffuser 5 is easily pushed out. For this reason, it is possible to perform stable air diffusion over a long period of time without closing the gas discharge unit with the solid content dried inside the air diffusion tube 5.

The air diffusion header tube 10 and the air diffusion tube 5 are
In particular, when the air diffusion pipe 5 is not connected through the air supply pipe 9 having a larger airflow resistance than the air diffusion pipe 5, a sufficient pressure to be discharged to the air diffusion pipe 5 cannot be obtained. Since it is known in the length direction of the diffuser tube 5 and the hydraulic pressure is different, it is difficult to uniformly diffuse air from the slit-shaped opening portion 8, and it is necessary to arrange the diffuser tube 5 substantially horizontally. .

According to the present embodiment, the supply of air from the single diffuser header tube 10 to the several diffuser tubes 5,..., 5 is performed by the individual supply tubes 9 having high ventilation resistance. . The air supply pipe 9 preferably has a ventilation resistance of about 1.2 to 3 times that of the air diffusion pipe 5. The inner diameter and length of the air supply pipe 9 may be determined according to the positions and distances at which the air diffusion header pipe 10 and the air diffusion pipe 5 are disposed.

The cross-sectional shape of the air diffuser 5 is circular, elliptical,
Alternatively, the shape may be a polygon or the like. The thickness is not particularly limited. However, if the thickness is too small, the pressure loss increases, and it becomes difficult to send a gas at a required flow rate, and the gas discharge portion may be blocked. On the other hand, if the air diffuser 5 is too thick, gas at the required pressure cannot be obtained in the air diffuser 5, and the pressure balance of the gas discharge portion of the air diffuser 5 is likely to be lost, and uniform air diffusion cannot be achieved. There is. Therefore, it is preferable that the cross-sectional area of the diffuser tube 5 to about 7～2000Mm ² mm, more preferably in a further about 20 to 500 mm ² approximately.

The slit-shaped opening 8 is provided in the air diffuser 5
In order to accumulate gas inside and generate gas from the entire slit, it is necessary to provide the gas below the angle not exceeding 30 ° above the horizontal plane passing through the center line of the air diffuser 5. More preferably, it is provided on a horizontal plane passing through the center line. When the slit-shaped opening 8 is provided at an angle of 30 ° above a horizontal plane passing through the center line, a portion near the discharge port of the air supply pipe 9 of the slit-shaped opening 8 near the gas supply unit such as the blower 4 or the like. , Air bubbles are ejected preferentially, and uniformity of air diffusion cannot be maintained.

The slit-shaped opening 8 may be provided so as to intersect with the longitudinal direction of the diffuser tube 5 or may be provided at an angle, but by forming it in parallel along the longitudinal direction. This is more preferable because the uniformity of air diffusion can be sufficiently ensured. The number of slits in the slit-shaped opening 8 is not particularly limited, but it is most preferable that only one slit is provided along the longitudinal direction of the air diffuser 5. Similarly, the slit shape is not particularly limited, and any shape such as a linear shape and a wavy shape can be adopted.

If the width of the slit-shaped opening 8 is too short, it may be blocked by dried solids. On the other hand, if the width is too wide, it is difficult to uniformly diffuse air throughout. For this reason, it is preferable that the width of the slit-shaped opening 8 is in a range of about 1 to 10 mm.

The length of the slit opening 8 is also
If the length is too short, the range in which air can diffuse is narrow, and it may be difficult to ensure uniformity. On the other hand, if the slit-shaped opening 8 is too long, it is difficult to uniformly diffuse air throughout. Therefore, the length of the slit-shaped opening 8 is about 30 to 200.
It is preferable to set the range to about mm. In the present invention, when a plurality of slit-shaped openings 8 are provided for one air diffuser 5, the length of the slit-shaped openings 8 is defined as a plurality of slit-shaped openings 8. Means the total length of

The air supply to the air diffuser 5 may be branched from an air supply source such as the blower 4 and connected via an air supply pipe 9 having a larger airflow resistance than the air diffuser 5.
In order to keep the pressure balance between the diffuser tubes 5 as constant as possible, a diffuser header tube 10 is provided as shown in FIG. 3, and the diffuser tube 5 is connected via an air supply tube 9 having a larger airflow resistance than the diffuser tube 5. Preferably, they are connected.

At this time, it is preferable that the sectional area of the diffuser header tube 10 is larger than the sectional area of the diffuser tube 5 in order to keep the pressure balance constant. The cross-sectional area of the diffuser header tube 10 is 60
% Is more preferable. The cross-sectional shape of the diffuser header tube 10 is not particularly limited, and may be any shape such as a circle, an ellipse, and a polygon.

The position of the diffuser header tube 10 is as follows:
Although not particularly limited, when the supply of air is stopped, it is preferably provided at a position higher than the water level of the liquid to be treated in order to prevent the liquid to be treated from entering the inside of the diffuser header tube 10.

The case where the air diffuser 3 of the present invention is used and the case where the air diffuser is not used are compared below. (Specific Example 1) Three hollow fiber membrane modules (trade name: Stellapore L, manufactured by Mitsubishi Rayon Co., Ltd.) in which a polyethylene hollow fiber membrane for microfiltration having an average pore diameter of 0.1 μm is developed and fixed in a screen shape, are hollow fibers. The length of the membrane in the fiber axis direction is 75cm
The screen faces in the vertical direction, and the screen modules are arranged side by side so that the center interval between the adjacent membrane modules is 6 cm, and the length is 80 cm, the width is 20 cm, and the height is 50 c.
The membrane separation device 2 housed in a casing having a vertical opening of m was immersed in the activated sludge tank 1.

Below the membrane module, an air diffuser 3 was provided at a distance of 45 cm from the lower end. The air diffusing device 3 is composed of six air diffusing tubes 5 each formed of a vinyl chloride pipe having an inner diameter of 1.3 cm arranged at a distance of 15 cm from each other so as to be perpendicular to the longitudinal direction of the hollow fiber membrane. Was placed. The horizontal portion of the air diffuser 5 has a length of 15 cm, and a slit-shaped opening 8 having a length of 100 mm and a width of 4 mm from the end thereof is provided on a horizontal plane passing through the center line of the air diffuser 5. The part 7 was opened. The diffuser pipe 5 is formed of a vinyl chloride pipe having an inner diameter of 5 cm and a length of 80 cm above the water surface of the activated sludge tank 1 through an air supply pipe 9 made of a nylon tube having an inner diameter of 8 mm and a length of 1 m. It was connected to the diffuser header tube 10.

Using a suction pump, the membrane filtration flow rate LV = 0.
Suction filtration was performed for 6 months by intermittent operation of ² m ³ / m ² / d and a suction / stop interval of 13 minutes / 2 minutes. The SS concentration in the activated sludge tank 1 during the operation period is 8000 to 12000 mg
/ L, and air was supplied using the blower 4 at an intensity of 100 Nm ³ / m ² / hr per horizontal cross-sectional area of the casing of the membrane separation device 2.

In Example 1, when the gas discharge portions of the air diffuser 3 were confirmed after the operation for six months, no blockage was observed in all the six air diffusers 5, and the uniformity of the air diffuser was not confirmed. Good, and the differential pressure of the membrane was +8 kPa from the start of operation.
And the vehicle was able to operate satisfactorily and stably.

(Specific Example 2) Except for the following points, a filtration test was performed under the same conditions as those of Specific Example 1 above. That is, without using the air diffusion header tube 10, the six air diffusion tubes 5 were connected to an air supply source via individual air supply tubes 9 formed of nylon tubes having an inner diameter of 8 mm and a length of 1 m.

In Example 2, when the gas discharge portion of the air diffuser 3 was confirmed after the operation for six months, the slit-shaped opening 8 of one of the six air diffusers 5 was observed. Although the adhering of the dried sludge was observed only in a part, the uniformity of the air diffusion was good. Further, the differential pressure of the membrane was only increased by +14 kPa from the start of the operation, and the operation was successfully and stably performed.

Comparative Example 1 A filtration test was performed under the same conditions as in Example 1 except for the following points. That is, the air diffuser 5 is an air supply pipe 9 having the same diameter as the air diffuser 5, and is connected to the air diffuser header 10 disposed in the activated sludge 1. The diffuser header tube 10 was disposed above the diffuser tube 5 at an interval of 50 cm.

In Comparative Example 1, when the gas discharge portion of the air diffuser 3 was confirmed after the operation for six months, the dry sludge was partially inserted into the four slit-shaped openings 8 of the six air diffusers 5. Was observed, and the diffused state also had a problem in uniformity. In addition, the membrane showed an increase in the differential pressure, which was +42 kPa after 6 months from the start of operation, exceeding the practical range. +55 kPa from the start of operation
And it was beyond the practical range.

As described above, according to the air diffuser 3 of the present embodiment, the air diffuser 3 is not blocked for a long period of time, and stable solid-liquid separation can be performed. In addition,
The present invention is not limited to the above-described embodiments, but naturally includes a technical range that can be easily changed by those skilled in the art from those embodiments.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a solid-liquid separation device 11 showing an example of a typical embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of an air diffuser in the solid-liquid separator 11;

FIG. 3 is a schematic view showing an example of the air diffuser 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Membrane separation tank 2 Membrane separation device 3 Air diffusion device 4 Blower 5 Air diffusion tube 6 Gas discharge hole 7 Tip opening 8 Slit opening 9 Air supply tube 10 Air diffusion header tube 11 Solid-liquid separation device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Honjo 4-160 Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture Inside Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Katsuyuki Yone Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture 4-160 No. 1-60 Mitsubishi Rayon Co., Ltd. Product Development Laboratory F-term (reference) 4D006 GA06 GA07 HA01 HA21 HA41 HA93 JA31A JA31B KA12 KA43 KA44 MA01 MA02 MA03 MC03 MC16 MC22 MC29 MC33 MC37 MC62 PA02 PB08 PB24 PC64 4D028 BC17 BC24 BD17 4D0 AA01 AB05 DD01

Claims (8)

[Claims] 1. A solid-liquid separation device comprising: a membrane separation device provided inside a membrane separation tank; and an air diffusion device provided below the membrane separation device. Is provided with an air diffuser having a gas discharge portion and extending in a substantially horizontal direction, and an air supply tube that is a supply path of air to the air diffuser, and an air supply tube having a larger airflow resistance than the air diffuser. A solid-liquid separation device connected to an air supply source via 2. The solid-liquid separation device according to claim 1, wherein the air diffuser is connected to the air diffuser header via the air supply pipe. 3. The air diffuser tube has an opening at its tip end and is 30 ° above a horizontal plane passing through the center line of the air diffuser tube.
The solid-liquid separation device according to claim 1 or 2, wherein a slit-like opening is provided in a lower portion that does not exceed the angle. 4. The width of the slit-shaped opening is 1 to 10 m.
The solid-liquid separation device according to any one of claims 1 to 3, wherein m and the length are 30 to 200 mm. 5. The cross-sectional area of the air diffuser is 7 to 2000 mm.
The solid-liquid separation device according to any one of claims 1 to 3, which is ( ² ). 6. The solid-liquid separator according to claim 2, wherein the diffuser header tube has a cross-sectional area larger than a cross-sectional area of the diffuser tube. 7. The solid-liquid separation device according to claim 6, wherein a cross-sectional area of the diffuser pipe is 60% or less of a cross-sectional area of the diffuser header pipe. 8. The air diffusion header tube is arranged at a position higher than a liquid level of a liquid to be treated in the membrane separation tank.
8. The solid-liquid separation device according to any one of 6 and 7.