JP2659475B2 - Solid-liquid separator - Google Patents

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 separating a liquid to be treated by a membrane filtration apparatus.

[0002]

2. Description of the Related Art Conventionally, a suction pump is connected to a membrane filtration device installed in a liquid to be treated, as a solid-liquid separation device for separating a liquid to be treated such as sewage or the like into a solid-liquid mixture by a membrane filtration device. Suction filtration of the liquid to be treated is widely used, and during continuous operation, solid substances adhere to the filtration membrane of the membrane filtration device and increase the filtration resistance. After stopping, air was sent in at any time by a blower to perform backwashing.

[0003]

However, such a configuration requires both a pump for filtering the liquid to be treated in the membrane filtration device and a blower for backwashing.
Equipment costs are high and space for installation is also large. SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-liquid separation device that can be installed at a low cost, save installation space, and is easy to maintain.

[0004]

In order to achieve this object, a solid-liquid separation device according to the present invention is characterized in that a suction portion of the air lift pump is connected to the membrane filtration device through a connection path, The discharge part of the air lift pump is formed at the discharge part of the filtrate, and a blower for supplying suction force of the air lift pump and supplying backwash air for the membrane filtration device is provided. The membrane filtration device is provided with a switching valve for selectively switching the supply of air from the blower.

[0005]

With this configuration, when the switching valve is switched to one side and the air from the blower is sent to the air lift pump, the liquid to be treated is filtered through the connection path by the suction force generated by the air. By suction-filtering through the device, the filtrate can be discharged from the discharge part, and when the switching valve is switched to the other side and air is directly supplied to the membrane filtration device, the membrane filtration device can be backwashed.

[0006]

Therefore, unlike the prior art, there is no need for both a pump for filtering the liquid to be treated in the membrane filtration device and a blower for backwashing, and the switching valve is provided simply by providing one blower. By switching, it can be used for both the purpose of suction-filtrating the liquid to be treated through the membrane filtration device and the purpose of backwashing the membrane filtration device. In addition, an air lift pump is used instead of the conventional pump. However, since this can be a simple structure in which a single pipe is placed vertically, for example, the equipment cost or the space occupied by the pump is the same as that of the conventional pump. The maintenance and management are extremely easy because there are no moving parts as in conventional pumps, and there is no possibility of failure due to overload or idling. Further, by using an air lift pump, even with a simple operation such as supplying air at a constant flow rate, if the water level of the water to be treated rises, the suction force increases and the filtration of the membrane filtration device increases. As the speed increases and the water level decreases, the suction force decreases and the filtration speed decreases. Therefore, even if there is a change in the amount of water to be treated, etc., the filtration speed automatically changes in a proportional control manner following the change, so that the water level is easily maintained substantially constant. It is easy to control the water level even for high-concentration slurry-like liquid to be processed, for which it is difficult to use a float or a pressure sensor for surface control.

[0007] As a result, a solid-liquid separation device can be provided which can save installation space at a low cost of equipment and operation, and can be easily maintained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show an example in which the solid-liquid separation device according to the present invention is used for solid-liquid separation of a liquid to be treated in a contact aeration tank second chamber E2 of a septic tank. This septic tank is the first anaerobic filter tank from upstream.
Room N1, Anaerobic filter bed second room N2, Contact aeration tank first room E
1. The contact aeration tank second chamber E2 is provided in this order. In the figure, F1 and F2 are filter beds for growing and fixing anaerobic microorganisms that decompose and solubilize and gasify organic substances in the water to be treated. C1 and C2 are contact materials for growing and fixing aerobic microorganisms that oxidize and decompose organic substances. As shown in the side sectional view and the front sectional view in FIGS. 1 and 2, the air lift pump 4 is provided in the second chamber E2 of the contact aeration tank.
And a blower 5 for sending air through the air lift air supply passage 1, and a suction portion 4 s of the air lift pump 4 is connected to the membrane filtration device 3 via a connection line 8, and the air is blown. A discharge part 4d is formed in the upper part of the lift pump 4 in the filtrate discharge part 7, and a backwash air supply path 2 for supplying air from the blower 5 to the membrane filtration device 3 is provided. A switching valve 6 for selectively supplying the discharge air from the air supply line to the air lift supply passage 1 and the backwash supply passage 2 is provided to constitute a solid-liquid separation device.

The air lift pump 4 is a hollow PV.
Using a C pipe, the upper end is an air vent opening 4c.
The height of the opening 4c is sufficiently high so that the filtrate does not blow out from the opening 4c. The air lift air supply passage 1 is provided so that the air lift air is supplied only to the air lift pump 4, that is, does not go to the membrane filtration device 3 via the connection passage 8. Is connected to the air lift pump 4 at a position slightly higher than the suction section 4s. Drainage from the discharge section 3 is discharged through a disinfection tank 10.

The membrane filtration device 3 is provided at a lower limit water level for controlling the secondary treatment tank. For this reason, when the water level falls to the lower limit water level, air is sucked in. As a result, filtration is not performed until the water level recovers.

[0011] The suction force of the air lift pump 4 is increased so that the suction force of the air lift pump 4 is increased and the backwash air is supplied only to the membrane filter device 3 when the membrane filter device 3 is backwashed. Is provided at a position lower than the membrane filtration device 3.

In the figure, D1 and D2 are air diffusers for supplying air to the aerobic microorganisms growing on the contact materials C1 and C2 and circulating the water to be treated containing organic matter to make good contact therewith. The filtration device 3 is provided at a suitable distance directly above the air diffusion device D2, and is located between the membrane filtration device 3 and the air diffusion device D2 and at a position close to the membrane filtration device 3 from the air diffusion device D2. Air is collected and this air is passed through a membrane filtration device 3
A convergence guide 12 is provided so that the convergence guide 12 can be used to prevent surface clogging. 14 and 15 in the figure
Is a valve for adjusting the air flow rate to the air diffusers D1 and D2, which is always open during sewage treatment.

With the above configuration, one blower 5
Normally, air is sent to the air lift pump 4 via the air lift air supply passage 1 to filter the sewage through the membrane filtration device 3 by the suction force generated by the air, and the sludge is added to the filtration membrane of the membrane filtration device 3. When the filtration resistance increases due to the adhesion of the like, the switching valve 6 is switched to send air to the membrane filtration device 3 through the backwash air supply path 2 to perform the backwash, thereby reducing the equipment cost. The solid-liquid separation device which can save the space for installation at the operating cost, and is easy to maintain can be provided. In addition, always using the air for aeration from the air diffuser D2, the rising foam powder and the water flow are collected by the convergence guide 12 and collided with the membrane surface, whereby clogging of the surface can be prevented. Even if the number of backwashing is greatly reduced, sewage treatment will not be affected. Therefore, maintenance is particularly easy.

[Another Embodiment] The operation of switching the air supply destination of the contact aeration tank second chamber E2 to the air lift pump 4 and the membrane filtration device 3 described in the above embodiment is described in, for example, FIG.
As shown in (2), a configuration in which a stop valve that performs only an opening / closing operation is used as the switching valve 6 may be adopted. The suction part 4s of the air lift pump 4 is connected to the membrane filtration device 3
To the disinfecting tank 10 as a discharge part 7 of the filtrate, and to apply the suction force of the air lift pump 4 and the reverse of the membrane filtration device 3. A blower 5 for supplying washing air is provided, and a switching valve 6 for selectively switching the supply of air from the blower 5 to the air lift pump 4 and the membrane filtration device 3.
Is provided. In the figure, reference numerals 13, 14, and 15 denote valves for adjusting the air flow rate, which are always open during sewage treatment. With the solid-liquid separation device having the above configuration, with one blower 5,
Normally, air is sent to the air lift pump 4 via the air supply path 1 by keeping the switching valve 6 open while constantly sending air for aeration to the air diffusers D1 and D2, and suction caused by the air is supplied. Membrane filtration device 3 by force
The sewage can be filtered through. Further, when sludge or the like adheres to the filtration membrane of the membrane filtration device 3 and the filtration resistance increases, if the switching valve 6 is closed, the membrane filtration device 3 is connected to the membrane filtration device 3 via the air supply passage 1 and the connection passage 8. Since the air is sent, the membrane filter 3 can be backwashed. Further, by installing the automatic valve 16 and closing it at the time of membrane backwashing, backwashing is more completely performed.

The present invention can also be used for membrane separation of activated sludge and the like.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an outline of an embodiment.

FIG. 2 is a front sectional view showing an outline of an embodiment.

FIG. 3 is a side sectional view showing an outline of another embodiment.

[Explanation of symbols]

 Reference Signs List 3 membrane filtration device 4 air lift pump 4s suction unit 4d discharge unit 5 blower 6 switching valve 7 discharge unit 8 connection path

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Dai Harada 2 at Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Kubota Shiga Plant (72) Inventor Kazuyuki Honda Kazuyuki, Koga-cho, Koga-gun, Shiga (1) Inside the Kubota Shiga Plant (72) Inventor Katsuro Ishihara 2 at Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Kubota Shiga Plant (72) Inventor, Mikiharu Tokushima, 2 Takamatsu, Kosai-cho, Koga-gun, Shiga 1 Kubota Corporation Shiga Plant (56) References JP-A-4-215893 (JP, A)

Claims (1)

(57) [Claims] An apparatus for solid-liquid separation of a liquid to be treated by a membrane filtration device (3), comprising an air lift pump (4), and a suction part (4s) of the air lift pump (4). Is connected to the membrane filtration device (3) via a connection path (8), and a discharge part (4d) of the air lift pump (4) is formed in a filtrate discharge part (7). A blower (5) for applying suction force of a lift pump (4) and supplying backwashing air for the membrane filtration device (3) is provided, and the air lift pump (4) and the membrane filtration device (3) are selected. A solid-liquid separation device provided with a switching valve (6) for selectively switching the supply of air from the blower (5).