JPH10235388A - Air diffusion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge easily sludge permeated into an air diffusion pipe at the time of maintenance by disposing the air diffusion pipe with a plurality of air diffusion openings below a plurality of membrane units set on a membrane separating device to be immersed in an aeration tank. SOLUTION: A membrane separating device 8 is disposed on an aeration tank 2 to be immersed into a mixed solution 7 of active sludge with water to be treated. The membrane separating device 8 is provided with a casing 9 with its upper and lower open, and a plurality of plane membrane units 10 are disposed in parallel in the up and down direction in the casing 9. An air diffusion device 1 is set below the membrane units 10, and an air diffusion pipe 4 with air diffusion openings formed at proper intervals is formed on the air diffusion device 1, and an opening and closing cover 15 is provided to be opened and closed on the end of the air diffusion pipe 4. The opening and closing cover 15 is constituted not to be opened and closed by the air pressure at the time of aeration. Sludge permeated into the air diffusion pipe 4 can be discharged easily at the time of aeration to eliminate cloggings by the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air diffuser. More specifically, the present invention relates to an air diffuser that is particularly effective for a nitrogen removal type membrane separation device that can easily discharge sludge that has entered a diffuser tube during maintenance and can eliminate clogging. .

[0002]

2. Description of the Related Art An aeration tank of a septic tank is often provided with a membrane separation apparatus. In this membrane separation apparatus, for example, as shown schematically in FIG. It is installed at the bottom of (2). The air diffuser (1) includes an air diffusion tube (4) formed of a suitable material such as polyvinyl chloride and having a plurality of air diffusion holes (3) each having a diameter of several mm and formed to face downward. . An air supply pipe (5) is connected to the proximal end of the air diffuser (4), and the air diffuser (4) communicates with the blower (6). The air diffuser (1) supplies air sent from a blower (6) as an air supply means through an air supply pipe (5),
A mixed liquid (7) of activated sludge and water to be treated, which can be supplied from the air diffusion hole (4) of the air diffusion pipe (4) into the aeration tank (2) and stored in the aeration tank (2). Oxygen dissolves in the air, and at the same time, due to the air lift effect, a membrane surface scavenging flow capable of cleaning the membrane unit disposed above the diffuser pipe (4) and immersed in the mixed solution (7) is generated.

[0003]

However, in a so-called batch type membrane separation type purification system in which an anaerobic state and an aerobic state are realized in a single tank and nitrogen is removed, aeration is intermittent for removing nitrogen. When the air diffusion is stopped, the mixed liquid (7) of the activated sludge and the water to be treated is supplied to the air diffuser (4) through the air diffusion hole (3). And clogging easily occurs.
The clogging that occurs in the air diffuser (1) is remarkable due to the presence of the activated sludge, which causes a reduction in the life of the membrane unit and a reduction in the processing capacity.

[0004] When the air diffusion hole (3) is closed, the flow velocity of the membrane surface sweeping flow on the air diffusion hole (3) decreases, so that a cake layer due to sludge accumulates on the membrane surface of the membrane unit. The formation of the sludge cake layer causes a decrease in the permeation flow rate of the membrane unit and an increase in the membrane suction pressure, and also causes a partial blockage of the flow path of the air diffuser (1). As a measure to prevent clogging of the air diffusion hole (3), it is conceivable to increase the diameter of the air diffusion hole (3). This lowers the horizontal tolerance of the trachea (4), and eventually causes clogging, which does not completely eliminate the clogging.

[0005] This is because the air diffuser (1) not only blocks the air diffusion holes (4) with the sludge dried in the form of a skin, but also completely fills the air diffusion pipe (4) with the sludge. This is because clogging may occur even in the form of るWhen the diffuser pipe (4) is completely filled with the sludge in this way, for example, it is conceivable that tap water or the like is supplied into the pipe, and the sludge is discharged out of the pipe and washed by the water pressure at that time. But,
Since the sludge discharge part is limited to the diffuser hole (3), it is substantially difficult to discharge the intruded sludge.

After all, when clogging occurs in the air diffuser (1), it seems that the air diffuser (1) must be temporarily removed from the aeration tank (2) and the air diffuser (4) must be cleaned or replaced. There is, but this is not the case. That is, in the immersion type membrane separation device, the air diffuser (1) is disposed below the membrane unit, so that it is not easy to take out the air diffuser (1). In order to take out the air diffuser (1), some kind of guide mechanism is required, and since this guide mechanism is quite complicated, it is necessary to take out the air diffuser (1) in order to eliminate clogging. Is by no means a valid solution.

The present invention has been made in view of the above circumstances, and solves the drawbacks of the conventional air diffuser, easily discharges sludge that has entered the air diffuser at the time of maintenance, and reduces clogging. It is an object of the present invention to provide a diffuser that can be eliminated.

[0008]

The present invention solves the above-mentioned problems by disposing below a plurality of membrane units provided in a membrane separation device immersed in an aeration tank,
There is provided an air diffusion device comprising: an air diffusion tube having a plurality of air diffusion holes; and an opening / closing lid provided at the end of the air diffusion tube so as to be openable and closable and not opened by air pressure during aeration. .

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a diffuser according to the present invention. FIG. 1 is a cross-sectional view showing an outline of the air diffuser of the present invention. Water to be treated is supplied to the aeration tank (2) in which the air diffuser (1) is installed by a transfer pump from a flow rate adjustment tank. In this aeration tank (2), batch type membrane separation type purification is performed, and nitrogen contained in the water to be treated is also removed.

In such an aeration tank (2), a membrane separation device (8) is disposed so as to be immersed in a liquid mixture (7) of activated sludge and water to be treated. The membrane separation device (8) includes a casing (9) with an open top and bottom, and a plurality of flat membrane units (10) are arranged in the casing (9) in parallel with each other in the up-down direction. Membrane unit (10)
Are each formed by attaching an organic filtration membrane to both surfaces of a hollow structure, and also include a filtered water suction pipe (11). The filtered water suction pipe (11) has a treated water suction pipe (1) communicating with a treated water tank (12) such as a disinfection tank.
3) are connected. For example, a suction pump (14) which can be provided in the middle of the treated water suction pipe (13).
By making the suction unit such as a negative pressure, the membrane unit (1
The membrane treatment of the mixed solution (7) according to 0) is performed, and the treated water after filtration is transferred to the treated water tank (12).

[0011] The membrane separation device (8) also includes an air diffuser (1). The air diffuser (1) is installed below the plurality of membrane units (10) in the aeration tank (2). Similar to the air diffuser (1) shown in FIG. 7, the air diffuser (1) has an air diffuser tube (not shown) having a diameter of about 4-8 mm and formed at appropriate intervals. 4). The air diffuser (4) is supported by the casing (9) at both ends thereof, and is arranged below the plurality of membrane units (10). In addition, a diffuser (4)
Is a blower (6) serving as an air supply means via an air pipe (5).
Is in communication with The air sent from the blower (6)
It is sent into the air diffuser (4) through the air supply pipe (5), and flows out as air bubbles into the aeration tank (2) through the air diffuser hole. Part of the oxygen in the air is dissolved in the mixture (7) of the activated sludge and the water to be treated, and an aerobic state is formed.
In the aerobic state, adsorption and oxidation of organic matter by activated sludge and oxidation (nitrification) of nitrogen are performed. The air generates a circulating flow in the mixed liquid (7) in the aeration tank (2) by an air lift effect, and peels off and cleans the cake layer attached to the membrane unit (10) by the shearing force of the bubbles themselves.

The operation of the blower (6) is intermittent, and when stopped, the inside of the aeration tank (2) becomes anaerobic. In an anaerobic state, nitrified nitrogen is denitrified. These aerobic and anaerobic states are alternately and repeatedly formed, and the suction means such as the suction pump (14) is controlled so as to interlock with the operation of the blower (6) and perform the suction operation only during aeration. I have.

In the air diffuser of the present invention, an opening / closing lid (15) is provided at the tip of the air diffuser (4) so as to be openable and closable. The opening / closing lid (15) is configured not to be opened by air pressure during aeration. FIGS. 2A and 2B are a cross-sectional view and a front view, respectively, showing a main part of the air diffuser according to the first embodiment of the present invention.

In the air diffuser (1) shown in FIGS. 2A and 2B, the opening / closing lid (15) is supported by a rotating shaft (16) provided at the tip of the air diffuser (4). It is rotatable. The rotating shaft (16) is fixed to the tip of the air diffuser (4) by a shaft fixing part (17). Opening / closing lid (15)
Is also biased by a spring elastic body. The spring elastic body presses the opening / closing lid (15) against the tip of the diffuser tube (4) against the air pressure at the time of aeration, and generates a moment sufficient to close the tip of the diffuser tube (4). Has elastic properties. The discharge pressure of the blower (6) in the aeration is generally
It is about 16-18 kPa.

For example, the spring elastic body shown in FIG.
As shown in <b>, a torsion coil spring (18) is preferably employed. When the torsion coil spring (18) is provided, the shaft fixing portion (17) around the rotation shaft (16)
, One end of which can be fixed to the shaft fixing portion (17), and the other end can be brought into contact with the end face of the opening / closing lid (15). In this manner, the opening / closing lid (15) can be pressed against the tip of the diffuser (4) to generate a moment sufficient to close the tip of the diffuser (4).

The opening / closing lid (15) is provided by a spring elastic body such as a torsion coil spring (18) even when air is sent from the blower (6) through the air supply pipe (5) into the air diffusion pipe (4) during aeration. It is not opened by air pressure because it is biased as described above. For this reason, the tip of the air diffuser (4) is kept closed. Further, the air flows out into the aeration tank (2) only from the air diffusion holes formed in the air diffusion pipe (4).

On the other hand, at the time of maintenance set on the assumption that clogging occurs in the air diffuser (1), for example, a water supply pipe is connected to the air supply pipe (5) instead of the blower (6), and the air supply pipe is connected. When tap water (300 kPa) is supplied to the air diffuser (4) through (5), the water pressure at this time causes the opening / closing lid (1) to open.
5) rotates around the rotation axis (16) in the direction away from the tip of the air diffuser (4) and opens to open the tip of the air diffuser (4). The sludge that has entered the pipe through the diffuser hole is quickly discharged into the aeration tank (2) from the open end of the diffuser pipe (4) with the flow of water flowing through the diffuser pipe (4). The infiltrated sludge is completely discharged out of the pipe in about 1-2 minutes at a flow rate of 30 L / min.

In this way, clogging of the air diffuser (1) can be easily and easily eliminated without removing the air diffuser (1). At the time of maintenance, pressurized air having a higher pressure than the air sent from the blower (6) can be supplied to the air diffuser (4) in addition to tap water. In this case, a blower dedicated to eliminating clogging such as a compressor may be connected to the air supply pipe (5) instead of the blower (6) for aeration. In order to enable exchange connection of such a blower (6), a water supply pipe, a blower dedicated to clearing clogging, etc., a union (1) is provided at the end of the air supply pipe (5).
9) can be installed.

FIGS. 3A and 3B are a main part sectional view and a main part front view, respectively, showing a second embodiment of the air diffuser according to the present invention. The air diffuser (1) shown in FIGS. 3A and 3B has substantially the same configuration as the air diffuser (1) shown in FIGS. 2A and 2B except for a spring elastic body. doing. That is, the opening / closing lid (15) is supported by the rotating shaft (16) fixed to the tip of the air diffuser (4) by the shaft fixing portion (17) and is rotatable.

On the other hand, in the air diffusing device (1) shown in FIGS. 3A and 3B, the opening / closing lid (15) has a mass that cannot be opened by air pressure during aeration. doing. In the case of such an air diffuser (1), FIG.
The operation exactly the same as that of the air diffuser (1) shown in <b> is obtained. That is, the opening / closing lid (15) does not open during aeration, but closes the tip of the air diffuser (4) and holds this state. On the other hand, at the time of maintenance, for example, a water pipe is connected to the air supply pipe (5) instead of the blower (6), and tap water (300 kPa) is supplied to the air diffusion pipe (4) through the air supply pipe (5). ) Is rotated around the rotating shaft (16) in the direction away from the tip of the air diffuser (4) by the water pressure at this time, and opens to open the tip of the air diffuser (4). The sludge that has entered the pipe through the diffuser hole is quickly discharged into the aeration tank (2) from the open end of the diffuser pipe (4) with the flow of water flowing through the diffuser pipe (4). Infiltration sludge is
It is completely discharged out of the tube in about 1-2 minutes at a flow rate of 30 L / min. Clogging of the air diffuser (1) is easily and easily eliminated without removing the air diffuser (1).

FIGS. 4A and 4B are a main part sectional view and a main part front view, respectively, showing a third embodiment of the air diffuser of the present invention. In the air diffusing device (1) shown in FIGS. 4A and 4B, a rubber cap (20) is employed as the opening / closing lid (15), and is attached to the tip of the air diffusing pipe (4). . The rubber cap (20) is formed with a slit (21) having a large inner diameter of the air diffuser (4).
The slit (21) has such a thickness and a slit shape that the slit (21) cannot be opened by air pressure during aeration. The rubber hardness of the rubber cap (20) can be, for example, about 50 °, and the thickness of the slit (21) can be about 5 mm. As the slit shape, a cross shape as illustrated in FIG. 4 <b> is exemplified.

In the case of such an air diffuser (1), as in the previous embodiment, the opening / closing lid (15) does not open during aeration, but closes the tip of the air diffuser (4). This state is maintained. On the other hand, at the time of maintenance, for example, a water pipe is connected to the air supply pipe (5) instead of the blower (6), and tap water (300 kPa) is supplied to the air diffusion pipe (4) through the air supply pipe (5). ) Is rotated around the rotating shaft (16) in the direction away from the tip of the air diffuser (4) by the water pressure at this time, and opens to open the tip of the air diffuser (4). The sludge that has entered the pipe through the diffuser hole is quickly discharged into the aeration tank (2) from the open end of the diffuser pipe (4) with the flow of water flowing through the diffuser pipe (4). Infiltration sludge is 3
At a flow rate of 0 L / min, it is completely discharged out of the tube in about 1-2 minutes. Clogging of the air diffuser (1) is easily and easily eliminated without removing the air diffuser (1).

FIGS. 5A and 5B are a main part sectional view and a main part front view, respectively, showing a fourth embodiment of the air diffuser of the present invention. In the air diffusing device (1) shown in FIGS. 5A and 5B, the open / close lid (15) except for the spring elastic body has the air diffusing device (1) shown in FIGS. 2A and 2B. ).

That is, the opening / closing lid (15) is supported by a rotating shaft (16) fixed to the tip of the air diffuser (4) by a shaft fixing portion (17) so as to be rotatable. on the other hand,
In the air diffuser (1) shown in FIGS. 5A and 5B, a cable (22) is housed as a guide member in an air diffuser (4). The cable (22) is connected to the opening / closing lid (15) at one end, and the other end of the cable (22) is
As shown in (1), it is drawn out of the aeration tank through the air supply pipe (5). The guide member such as the cable (22) is fixed in a tensioned state when it is aerated. For this reason, the opening / closing lid (15) does not open due to the tension of the guide member such as the cable (22), but closes the tip of the air diffuser (4) and holds this state. On the other hand, during maintenance,
The tension of the guide member such as the cable (22) is released by hand, and the guide member such as the cable (22) is operated from the ground to move the opening / closing lid (15) away from the tip of the air diffuser (4). Extrude, open the opening / closing lid (15), and open the tip of the air diffuser (4). In this state, for example, a water supply pipe is connected to the air supply pipe (5), and tap water is supplied through the air supply pipe (5), as in the case of the air diffuser (1) shown in FIGS. I do. Then, the sludge that has entered the pipe through the diffuser hole is discharged into the aeration tank (2) promptly from the open end of the diffuser pipe (4) with the flow of water flowing through the diffuser pipe (4). . 30 L of infiltrated sludge
It is completely discharged out of the tube in about 1-2 minutes at a flow rate of / min. Clogging of the air diffuser (1) is easily and easily eliminated without removing the air diffuser (1).

Of course, the present invention is not limited by the above embodiments. Including the diffuser,
It goes without saying that various aspects are possible for details such as the shape, material and structure of the opening / closing lid, the spring elastic body and the guide member.

[0026]

As described above in detail, according to the present invention, the sludge that has entered the air diffuser can be easily discharged during maintenance. Clogging of the air diffuser is easily and easily eliminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an outline of an air diffuser according to the present invention.

FIGS. 2A and 2B are a main part cross-sectional view and a main part front view, respectively, showing a first embodiment of the air diffuser of the present invention.

FIGS. 3A and 3B are a main part cross-sectional view and a main part front view, respectively, showing a second embodiment of the air diffuser of the present invention.

FIGS. 4A and 4B are a main part sectional view and a main part front view, respectively, showing a third embodiment of the air diffuser of the present invention.

FIGS. 5A and 5B are a main part cross-sectional view and a main part front view, respectively, showing a fourth embodiment of the air diffuser of the present invention.

FIG. 6 is a cross-sectional view schematically showing a main part of the entire air diffusing device shown in FIG. 5;

FIG. 7 is a side view showing an outline of a conventional air diffuser.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 diffuser 2 aeration tank 3 diffuser hole 4 diffuser pipe 5 air supply pipe 6 blower 7 mixed liquid of activated sludge and water to be treated 8 membrane separator 9 casing 10 membrane unit 11 filtered water suction pipe 12 treated water tank 13 treatment Water suction pipe 14 Suction pump 15 Opening / closing lid 16 Rotating shaft 17 Shaft fixing part 18 Torsion coil spring 19 Union 20 Rubber cap 21 Slit 22 Cable

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shin Shin, 1048, Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd.

Claims (5)

[Claims] 1. An air diffusion tube which is arranged below a plurality of membrane units provided in a membrane separation device immersed in an aeration tank and has a plurality of air diffusion holes, and which can be opened and closed at a tip of the air diffusion tube. And an opening / closing lid that is not opened by air pressure during aeration. 2. The opening / closing lid is rotatably supported by a rotating shaft provided at the tip of the diffuser tube, and is urged by a spring elastic body. 2. The air diffuser according to claim 1, wherein the air diffuser has an elastic property that presses the opening / closing lid against the tip of the air diffuser against the pressure, and generates a moment sufficient to close the tip of the air diffuser. 3. The diffuser according to claim 1, wherein the opening / closing lid is rotatably supported by a rotating shaft provided at the tip of the diffuser tube, and has a mass that cannot be opened by air pressure during aeration. Qi device. 4. The opening / closing lid is a rubber cap attached to the tip of the air diffuser tube, a slit having a large inner diameter of the air diffuser tube is formed, and the slit portion of the rubber cap is slit when air pressure during aeration is reached. The air diffuser according to claim 1, wherein the air diffuser has a thickness and a slit shape that do not open. 5. The opening / closing lid is rotatably supported by a rotating shaft provided at the tip of the diffuser tube, and a guide member housed in the diffuser tube is connected to the opening / closing lid. By being fixed in tension, the opening / closing lid does not open with air pressure, and holds the diffuser tube tip in a closed state.On the other hand, the guide member pushes the opening / closing lid in a direction away from the diffuser pipe tip, thereby opening / closing the lid. The air diffuser according to claim 1, wherein the air diffuser can be opened to open a tip of the air diffuser tube.