JPH0722750B2 - Membrane module of activated sludge treatment equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a membrane module of an activated sludge treatment device for organic wastewater.

Conventional technology Conventionally, in the activated sludge treatment device of organic wastewater,
For example, as shown in FIG. 4, a rectangular box frame 2 whose upper and lower surfaces are open is provided in the aeration tank 1, and a plurality of membrane modules 3 are vertically arranged in the box frame 2 at regular intervals a. An air diffuser 4 is arranged below the membrane module 3. Reference numeral 5 is a raw water supply pipe opening to the aeration tank 1, and 6 is a sludge drawing pump connected to the bottom of the aeration tank 1. The membrane module 3 is formed by coating both sides of a membrane support 7 curved in an uneven shape with a filtration membrane 8, and a permeate collection pipe via a permeate suction pipe 9 connected to the upper end of the membrane support 7. Connected to 10. The permeated liquid collecting pipe 10 is provided with a suction pump 11 on the way and opens into a permeated liquid tank 12. The air diffuser 4 is a blower via the air supply pipe 13.
Connected to 14.

The raw water 15 supplied from the raw water supply pipe 5 into the aeration tank 1 is digested by activated sludge in the tank to become digested water 16. At that time, the air diffuser 4 supplies the aeration gas 17 containing oxygen such as air supplied from the blower 14 to the membrane module 3
It is blown in between to supply oxygen to the microorganisms in the activated sludge. The digested water 16 is sucked by the suction pump 11 through the membrane module 3 and is solid-liquid separated by the membrane module 3. That is, the sludge in the digested water 16 is captured by the filter membrane 8, while the clean permeable membrane 18 that has permeated the filter membrane 8.
Is stored in the permeate tank 12 from the permeate suction pipe 9 through the permeate water collecting pipe 10. At that time, an ascending flow of the digestion-treated water 16 is generated between the membrane modules 3 due to the air lift action of the bubbles of the aeration gas 17, and this ascending flow makes it difficult to attach the sludge to the filtration film 8 No. 8 clogging was prevented.

However, in the above-mentioned conventional membrane module 3, in the suction state, a part of the filtration membrane 8 is brought into close contact with the convex portion of the membrane support 7 and the flow of the permeated liquid 18 between them. When the passage is eliminated, the suction force does not act effectively on that portion, and the filtration function is deteriorated. Therefore, there is a problem that the effective filtration area of the filtration membrane 8 is reduced and the filtration efficiency is reduced. Furthermore, since the structure is complicated and the thickness is large, the membrane module 3 becomes large and expensive, and it is not easy to handle.

It is an object of the present invention to improve the conventional membrane module and eliminate such problems.

Means for Solving the Problems In order to achieve the above object, the membrane module of the activated sludge treatment device of the present invention is immersed in an aeration tank to vertically and parallelly arrange a plurality of membrane modules, and adjacent to each other. A membrane module in an activated sludge treatment device in which a uniform gap is formed between the membrane modules to be provided, and an air diffusing means is provided below the membrane module, and the both sides of a rigid plate-shaped membrane support net are covered. A filtration membrane is provided, and a permeate flow path gap is formed by a membrane support net between the front and back filtration membranes, and the upper edge of the membrane support net is placed in a slit provided in the permeate suction pipe along the tube axial direction. The upper end opening of the bag-shaped filter membrane is fixed by adhering it to the suction tube, and the lower end of the membrane support net is superposed on the filter membrane and wound around the support rod to be fixed. It is configured to communicate with the permeate suction tube It is a thing.

Action In the above configuration of the present invention, when a suction force is applied to the permeated liquid suction tube, the digested water is sucked through the filtration membrane and solid-liquid separated. That is, the sludge in the digested water is captured by the filtration membrane, while the clean permeate that has permeated the filtration membrane passes through the flow passage gap formed by the membrane support net between the filtration membranes, The liquid is sucked into the permeated liquid suction pipe communicating with. At this time, the filtration membranes on both sides of the membrane support net are sucked inward by the suction force, but since they are held by the membrane support net, a flow path gap is always provided between the filtration membranes by the membrane support net. Maintained over the entire surface of. Therefore, the suction force acts on the entire surface of the filtration membrane, the reduction of the effective filtration area of the filtration membrane is prevented, and the filtration efficiency is improved. Further, since the filtration membrane is directly held by the membrane supporting net, the structure is simple and the thickness of the membrane module is thin. Therefore, the membrane module is small and inexpensive, and is easy to handle.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the activated sludge treatment device of this embodiment, as shown in FIG. 1, a box frame 22 is provided in the aeration tank 21, and a plurality of membrane modules 23 are vertically arranged at a constant interval A in the box frame 22. Array
An air diffuser 24 is arranged below the membrane module 23. To the aeration tank 21, a raw water supply pipe 25 is opened at the upper side, and a sludge drawing pipe 27 having a sludge drawing pump 26 at the bottom is connected. The box frame 22 has a rectangular shape and both upper and lower sides are open. The membrane module 23, as shown in FIG. 2 and FIG. 3, has both sides of a rectangular plate-shaped plastic membrane supporting net 28 for filtering membranes.
29, the upper edge of the membrane support net 28 is inserted into a slit 31 provided in the permeate suction tube 30 in the tube axial direction, and the lower end of the membrane support net 28 is superposed on the filtration membrane 29 to form a support rod. It is wrapped around 32 and fixed. The membrane support net 28 forms a permeate flow passage gap between the filtration membranes 29, and this flow passage gap communicates with the permeate suction pipe 30 via the upper end edge of the membrane support net 28 inserted in the slit 31. To do. The filtration membrane 29 is formed in a bag shape, and the periphery of the opening at the upper end is adhered to the permeated liquid suction tube 30 with an adhesive. Both ends of the permeated liquid suction tube 30 project outward from both side edges of the membrane support net 28, one end is open, and the other end is closed. Both ends of the support rod 32 also project outward from both side edges of the membrane support net 28. The membrane module 23 is a permeate suction tube.
The support 30 is fixed to the box frame 22 via the projecting ends of the support rod 32, and the end of the permeate suction pipe 30 on the opening side is connected to the permeate collecting pipe 33. The permeated liquid collecting pipe 33 is provided with a suction pump 34 in the middle thereof and opens above the permeated liquid tank 35. The air diffuser 24 is connected to the blower 37 via the air supply pipe 36.

Next, the operation of the above configuration will be described.

When the raw water 38 is supplied into the aeration tank 21 from the raw water supply pipe 25, the raw water 38 is digested by the activated sludge in the tank and the digested water is obtained.
39. At that time, the air diffuser 24 blows an aeration gas 40 containing oxygen such as air supplied from the blower 37 between the membrane modules 23 to supply oxygen to the microorganisms in the activated sludge. The digested water 39 is sucked by the suction pump 34 through the membrane module 23, and is solid-liquid separated by the membrane module 23. That is, the sludge in the digested water 39 is filtered by the filtration membrane 29.
On the other hand, the clean permeated liquid 41 that has been captured by the filter membrane 29 and has permeated through the filtration membrane 29 passes through the flow passage gap formed by the membrane support net 28 between the filtration membranes 29, and the permeated liquid suction that communicates with the flow passage gap The permeate tank is sucked into the pipe 30 and passes through the permeate collection pipe 33.
Stored in 35. At that time, the digested water 39 is provided between the membrane modules 23 by the air lift action of the bubbles of the aeration gas 40.
Is generated, the sludge attached to the filtration membrane 29 is separated from the filtration membrane 29, and the clogging of the filtration membrane 29 is prevented.

When the membrane module 23 performs solid-liquid separation of the digested water 39, the filtration membranes 29 on both sides of the membrane supporting net 28 are sucked inward by the suction force, but are retained by the membrane supporting net 28. Between the two filtration membranes 29, the membrane support net 28 always maintains a flow path gap over the entire surface of the filtration membrane 29. Therefore, the suction force acts on the entire surface of the filtration membrane 29, the reduction of the effective filtration area of the filtration membrane 29 is prevented, and the filtration efficiency is improved. Further, since the filtration membrane 29 is directly held by the membrane support net 28, the structure is simplified and the thickness of the membrane module 23 is reduced. Therefore, the membrane module 23
Is smaller, cheaper, and easier to handle.

As described above, according to the present invention, both sides of the membrane supporting net are covered with the filtration membrane, and the permeate passage gap is formed between the filtration membranes by the membrane supporting net. A flow path gap is formed, and the suction force acts on the entire surface of the filtration membrane. Therefore, it is possible to prevent the effective filtration area of the filtration membrane from decreasing and improve the filtration efficiency. Also, since the filtration membrane is directly held by the membrane support net,
In addition to the simple structure, the thickness of the membrane module is reduced. Therefore, the membrane module is small and inexpensive, and is easy to handle.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an activated sludge treatment device showing an embodiment of the present invention, FIG. 2 is a front view of the membrane module in FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is an overall configuration diagram showing an example of a conventional activated sludge treatment device. 23 …… Membrane module, 28 …… Membrane support net, 29 …… Filtration membrane, 30 …… Permeate suction tube, 31 …… Slit, 41 …… Permeate.

Claims (1)

[Claims] 1. A plurality of membrane modules are vertically and parallelly arranged by immersing the membrane modules in an aeration tank, and a constant gap is formed between adjacent membrane modules, and an air diffusing means is provided below the membrane module. A membrane module in an activated sludge treatment device, in which a filtration membrane is provided by covering both front and back sides of a rigid plate-shaped membrane support net, and a permeate flow path gap is provided between the front and back filtration membranes by the membrane support net. The upper end edge of the membrane support net is inserted into the slit provided in the permeate suction tube along the axial direction of the permeate, and the upper end opening of the bag-shaped filter membrane is fixed by adhering to the suction tube. A membrane module for an activated sludge treatment device, characterized in that the lower end of the membrane supporting net is superposed on a filtration membrane, wound around a supporting rod and fixed, and the channel gap is communicated with a permeate suction pipe.