JPH08332358A - Membrane separation device - Google Patents

Abstract

(57) [Summary] [Purpose] In a membrane separation device in which a membrane module is provided inside a treatment tank and an air diffusing means is arranged below the membrane module, even when the distance from the upper end of the membrane module to the water surface is large. The aeration air forms a smooth circulating flow so that the membrane surface of the membrane element can be effectively cleaned. [Structure] A rectifying plate 19 that guides the flow of the water 16 to be treated is provided on the upper part of the membrane module 2 along the upper edge of the membrane module 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane separation device used in water treatment such as water purification / sewage treatment and sludge concentration treatment.

[0002]

2. Description of the Related Art As a membrane separation device used in water treatment such as water purification / sewage treatment and sludge concentration treatment, there is a ceramic membrane separation device as shown in FIG.

In the ceramic membrane separation device, a plurality of immersion type membrane modules 2 are provided inside the treatment tank 1, a membrane permeated water extraction means 3 is connected to each membrane module 2, and an air diffuser 4 is provided below the membrane module 2. Is provided.

The membrane module 2 is, as shown in FIG.
Both ends of the plurality of tubular ceramic membrane elements 5 are respectively supported by headers 6 and 7, the membrane elements 5 are arranged in parallel at appropriate intervals, and the headers 6 and 7 are connected to the outer peripheral side of the plurality of membrane elements 5 to form a pair. Guide plates 8, 8 are provided in parallel. One header 6 is formed with a suction chamber 6a communicating with the permeated water channel 5a inside each membrane element 5, and a suction port 6b communicating with the suction chamber 6a and the outside of the header 6.

The membrane permeated water extraction means 3 has a suction pipe 9 communicating with the suction port 6b of the membrane module 2, a water collecting pipe 10 communicating with each suction pipe 9, and a permeate water pipe 11 communicating with the water collecting pipe 10.
And a suction pump 12 interposed in the permeated water pipe 11, and the permeated water pipe 11 is led to a treated water tank 13 outside the treatment tank 1.

The air diffuser 4 is a blower 1 outside the processing tank 1.
4 and the like, and aeration air 15 sent from the blower 14 is supplied to the water 16 to be treated in the treatment tank 1. Reference numeral 17 is a treated water supply pipe.

In the above-mentioned structure, the suction pump 12 is driven to apply suction pressure to the membrane element 5 while introducing the treatment water 16 into the treatment tank 1 through the treatment water supply pipe 17. (Or, due to the natural head of the water 16 to be treated in the treatment tank 1), a differential pressure is generated inside and outside the membrane element 5, and the water 16 to be treated is filtered by the membrane element 5. Then, the suspended substance in the water 16 to be treated is left in the tank 1, and the permeated water 18 permeating the membrane surface of the membrane element 5 and flowing into the permeate flow channel 5a is sucked into the suction pipe 9, the water collecting pipe 10, It is sent to the treated water tank 13 through the permeated water pipe 11.

At this time, aeration air 15 is supplied to the water 16 to be treated from the blower 14 through the air diffuser 4, and
The gas-liquid mixing upward flow generated by the aerated air 15 passes through the inside of the membrane module 2, that is, from one opening formed by the headers 6, 7 and the guide plates 8, 8 toward the other opening. By doing so, the membrane surface of the membrane element 5 is always washed.

The gas-liquid mixing upward flow that has passed through the inside of the membrane module 2 is made a downward flow outside the membrane module 2 to form a circulating flow inside and outside the membrane module 2 inside the treatment tank 1. By this circulating flow, the water 16 to be treated and the aerated air 15 (with activated sludge in the case of activated sludge treatment) are stirred and mixed, and an upward flow of gas-liquid mixing is promoted,
The cleaning of the membrane surface of the membrane element 5 is made effective.

[0010]

However, in the above-mentioned conventional membrane separation device, when the distance from the upper end of the membrane module 2 to the water surface is large, the upward flow rises to near the water surface as indicated by the arrow. Without moving, it moves horizontally and turns to downward flow. Therefore, near the water surface, the head difference caused by the upflow of gas-liquid mixture becomes small, and the water to be treated near the water surface is not supplied to the downflow side, so the circulation condition in the entire tank deteriorates, which causes the upflow. As a result of the decrease in the flow velocity of the film, there is a problem that the cleaning power of the film surface is decreased and fouling (contamination) easily progresses.

The present invention solves the above problem. Even when the distance from the upper end of the membrane module to the water surface is large, it is possible to form a circulating flow that circulates in the entire tank by the aerated air. An object of the present invention is to provide a membrane separation device capable of effectively cleaning the membrane surface of a membrane element.

[0012]

In order to solve the above-mentioned problems, the membrane separation apparatus of the present invention is provided with an immersion type membrane module having a plurality of membrane elements arranged inside a treatment tank, and the immersion type membrane module is provided below the membrane module. In the membrane separation device in which the diffusing means is provided, a rectifying plate for guiding the flow of the water to be treated is erected on the upper part of the membrane module along the upper peripheral edge of the membrane module.

Further, the membrane separation device of the present invention is provided with a straightening plate such that the upper end portion thereof is located in the range from the center position between the upper end portion of the membrane module and the water surface to the water surface.

[0014]

According to the above construction, the straightening vane divides the space between the upward flow side and the downward flow side formed inside and outside the membrane module, and the gas-liquid mixing upward direction generated by the aerated air is divided. The flow is guided above the membrane module by the straightening vanes,
Rise without moving horizontally. As a result, the head difference between the upflow side and the downflow side becomes large, and the treated water on the upflow side is forcibly supplied to the downflow side, and As a result of the smooth circulation flow, the membrane element is effectively cleaned on the membrane surface.

Further, the gas-liquid mixing upward flow generated by the aerated air is guided by the flow straightening plate and rises at least to the center between the upper end portion of the membrane module and the water surface, so that the upward flow side and the downward flow direction. An appropriate head difference is generated between the water and the side, and the water to be treated near the water surface circulates smoothly.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a membrane separation apparatus according to an embodiment of the present invention. Since this membrane separation apparatus has substantially the same structure as the conventional one described with reference to FIG. 2, it has the same operation as the conventional one. The members that have the same reference numerals as those in FIG.

The solid-liquid separation device of this embodiment is different from the conventional one in that a vertical rectifying plate 19 for guiding the flow of the water 16 to be treated is provided above the plurality of membrane modules 2. . The straightening vane 19 is provided so that the lower end 19a extends along the upper end peripheral portion of the membrane module 2 and the upper end 19b almost reaches the water surface.

According to the above construction, the flow straightening plate 19 is provided between the upflow side and the downflow side formed inside and outside the membrane module 19.
The upward flow of gas-liquid mixture generated by the aerated air is guided by the flow straightening plate 19 above the membrane module 2 and rises to almost the water surface without moving in the horizontal direction.

As a result, the head difference between the upflow side and the downflow side across the straightening plate 19 becomes large, and the treated water on the upstream side including the treated water near the water surface is treated. Since it is forcibly supplied to the downflow side, a smooth circulating flow is formed in the tank. As a result, a large membrane surface flow velocity is stably supplied, and the membrane element is effectively cleaned.

In this embodiment, the membrane module 2 which occupies almost half of the cross-sectional area of the treatment tank 1 is provided near the tank wall for the convenience of disposing the suction pipe 9. A rectifying plate 19 is provided on one side of the module 2,
A rectifying plate may be provided so as to surround the membrane module depending on the position of the membrane module in the treatment tank.

The rectifying plate 19 is preferably provided so that its upper end portion 19b is located in the range from the center between the upper end portion of the membrane module 2 and the water surface to the water surface. As a result, the gas-liquid mixing upward flow generated by the aerated air rises at least up to the center between the upper end of the membrane module 2 and the water surface, and an appropriate head difference between the upward flow side and the downward flow side. Occurs, and the water to be treated near the water surface is also circulated smoothly.

[0022]

As described above, according to the present invention, the upflow side and the downflow side are formed by partitioning the space between the upflow side and the downflow side formed inside and outside the membrane module with the flow straightening plate. Since the head difference between the upstream side and the upstream side is increased and the treated water on the upstream side is forcibly supplied to the downstream side, a smooth circulating flow can be formed in the tank. A large membrane surface flow velocity can be stably obtained. As a result, the progress of fouling in the membrane element can be suppressed and a high filtration capacity can be maintained for a long time.

Further, the straightening plate is provided so that the upper end thereof is located in the range from the center of the upper end of the membrane module and the water surface to the water surface, so that the straightening plate is provided between the upflow side and the downflow side. An appropriate head difference is generated, and the water to be treated near the water surface can be smoothly circulated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a solid-liquid separation device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an overall configuration of a conventional solid-liquid separation device.

FIG. 3 is a partially cutaway perspective view of a membrane module constituting the solid-liquid separation device shown in FIG.

[Explanation of symbols]

 1 treatment tank 2 membrane module 4 air diffuser 19 straightening plate 19a lower end 19b upper end

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiya Ozaki 2-6, Nishijima, Nishiyodogawa-ku, Osaka-shi, Osaka Kubota Shin-Yodogawa factory

Claims (2)

[Claims] 1. A membrane separation apparatus in which an immersion type membrane module having a plurality of membrane elements arranged therein is provided inside a treatment tank, and an air diffusing means is arranged below the membrane module, above the membrane module. A membrane separation device, characterized in that a rectifying plate for guiding the flow of water to be treated is erected upright along the upper edge of the membrane module. 2. The membrane separation apparatus according to claim 1, wherein the current plate is provided so that its upper end is located in the range from the center position between the upper end of the membrane module and the water surface to the water surface.