JPH034982A - Membrane module for activated sludge treating apparatus - Google Patents

Abstract

PURPOSE:To contrive the improvement of filtering efficiency by a method wherein filter membranes are provided covering each side of a membrane supporting net, filtrate passageways are defined between the filter membranes by the membrane supporting net and the membrane supporting net is engaged at one end into a slit provided in a filtrate suction pipe. CONSTITUTION:The sludge in a digesting water 39 is captured by filter membranes 29, while a clean filtrate 41 separated by the filter membranes 29 is sucked through passageways defined on a membrane supporting net 28 between the filter membrane 29 into a filtrate suction pipe 30 in communication with the passageways and stored in a filtrate tank 35 through a filtrate collecting pipe 33. When membrane modules 23 effect solid-liquid separation of the digesting water 39, the filter membrane 29 on each side of the net 28 are sucked inwardly by the sucking force but held by the net 28 and, therefore, the passageways are always maintained by the net 28 between both the filter membranes 29 over the entire surfaces of the filter membranes. For this reason, the sucking force is exerted over the entire surface of the filter membrane 29, thereby preventing the decrease of the effective filter area of the filter membrane 29 with an improved filtering efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a membrane module for an activated sludge treatment apparatus for organic wastewater.

Conventional technology Conventionally, in activated sludge treatment equipment for organic wastewater,
For example, as shown in FIG. 4, a rectangular box frame 2 with open top and bottom surfaces is provided in an aeration tank 1, and a plurality of membrane modules 3 are arranged vertically within the box frame 2 at regular intervals a. , a diffuser pipe 4 is arranged below the membrane module 3. 5 is a raw water supply pipe opening into 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 constructed by covering both sides of a membrane support 7 curved in an uneven shape with a filtration membrane 8, and a permeate collection pipe is connected to the permeate suction pipe 9 connected to the upper end of the membrane support 7. There are 9 connected to 10. The permeated liquid collection pipe 10 is provided with a suction pump 11 in the middle and opens into a permeated liquid tank 12 . The air diffuser 4 is connected to a blower 14 via an air supply pipe 13.

The raw water 15 supplied into the aeration tank 1 from the raw water supply pipe 5 is
The water is digested with activated sludge in the tank and becomes digested water 16. At that time, the aeration pipe 4 blows an aeration gas 17 containing oxygen, such as air supplied from the blower 14, between the membrane modules 3 to supply oxygen to the microorganisms in the activated sludge. is sucked by the suction pump 11 through the membrane module 3, and is separated into solid and liquid by the membrane module 3.

That is, the sludge in the digested water 16 is captured by the filtration membrane 8, while the clean permeate 18 that has passed through the filtration membrane 8 is passed from the permeate suction pipe 9 to the permeate collection pipe IO to the permeate tank. It is stored in 12. At this time, an upward flow of the digested water 16 is generated between the membrane modules 3 due to the air lift effect of the bubbles of the aeration gas 17, and this upward flow makes it difficult for sludge to adhere to the filtration membrane 8. 8 was prevented from clogging.

Problems that the invention aims to solve However, in the conventional membrane module 3 described above.

In the suction state, a part of the filtration membrane 8 comes into close contact with the convex part of the membrane support 7, and there is no flow path for the permeated liquid 18 between the two, and the suction force no longer acts effectively on that part, which prevents filtration. Function deteriorates. Therefore, there was a problem that the effective filtration area of the filtration membrane 8 was reduced and the filtration efficiency was lowered. Furthermore, since the structure is complicated and the membrane module 3 is thick, there are problems in that the membrane module 3 is large and expensive, and is not easy to handle.

The present invention aims to solve these problems by improving conventional membrane modules.

Means for Solving the Problems In order to achieve the above objects, the membrane module of the activated sludge treatment apparatus of the present invention is provided with filtration membranes covering both the front and back sides of a membrane support net, and a membrane support between the front and back filtration membranes. The net forms a flow path gap for the permeate.

One end edge of the membrane support net is inserted into a slit provided in the permeate suction tube, so that the flow path gap is communicated with the permeate suction tube.

Function In the above structure of the present invention, when a suction force is applied to the permeate suction tube, the digested water is suctioned through the filtration membrane and separated into solid and liquid. That is, the sludge in the digestion water is captured by the filtration membrane, while the clean permeate that has passed through the filtration membrane passes through the channel gap formed by the membrane support net between the filtration membranes. The permeate is sucked into the permeate suction tube that communicates with the permeate.

At this time, the filtration membranes on both sides of the membrane support net are sucked inward by the suction force, but because they are held by the membrane support net,
Between the surface filtration membranes, a flow path gap is always maintained over the entire surface of the filtration membranes by a membrane support net. Therefore, the suction force acts on the entire surface of the filtration membrane, preventing a decrease in the effective filtration area of the filtration membrane, and improving filtration efficiency. Furthermore, since the filtration membrane is directly supported by the membrane support net, the structure is simple and the thickness of the membrane module is reduced.

Therefore, the membrane module becomes smaller, cheaper, and easier to handle.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

In the activated sludge treatment apparatus of this embodiment, as shown in FIG. A diffuser pipe 24 is arranged below the membrane module 23. A raw water supply pipe 25 opens upward to the aeration tank 21, and a sludge drawing pipe 27 equipped with a sludge drawing pump 26 is connected to the bottom. The box frame 22 is rectangular and both upper and lower sides are open. As shown in FIGS. 2 and 3, the membrane module 23 has a rectangular plate-shaped plastic membrane support net 28 covered with filtration membranes 29 on both sides, and the upper edge of the membrane support net 28 connected to a permeate suction tube. 30 into a slit 31 provided in the tube axis direction, the lower end of the membrane support net 28 is overlapped with the filtration membrane 29 and wrapped around the support rod 32,
It is fixed. The membrane support net 28 forms a flow path gap for the permeate between the filtration membranes 29, and this flow path gap is connected to the permeate suction tube 30 via the upper edge of the membrane support net 28 inserted into the slit 31. It goes through. The filtration membrane 29 is formed in the shape of a bag, and the upper opening periphery is bonded to the permeate suction tube 30 with an adhesive. Both ends of the permeate suction tube 30 protrude outward from both side edges of the membrane support net 28, one end being open and the other end being closed. Both ends of the support rod 32 are also connected to the membrane support net 28.
It protrudes outward from both side edges. The membrane module 23 is fixed to the box frame 22 via the protruding ends of the permeate suction tube 30 and the support rod 32, and the six permeate tubes are connected to the open end of the permeate suction tube 30 to the permeate collection tube 33. Liquid collection pipe 33
is equipped with a suction pump 34 in the middle and opens above the permeate tank 35.

The air diffuser pipe 24 is connected to a blower 37 via an air supply pipe 36.

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

When raw water 38 is supplied into the aeration tank 21 from the raw water supply pipe 25, the raw water 38 is digested with activated sludge in the tank and becomes digested water 39. At that time, the diffuser pipe 24
Aeration gas 40 containing oxygen such as air supplied from 37 is blown between the membrane modules 23 to supply oxygen to microorganisms in the activated sludge. The digested water 39 is sucked through the membrane module 23 by the suction pump 34, and is separated into solid and liquid by the membrane module 23. That is, the sludge in the digested water 39 is captured by the filtration membrane 29, and on the other hand, the clean permeate 41 that has passed through the filtration membrane 29 flows through the channel gap formed by the membrane support member 28 between the filtration membranes 29. The permeate is sucked into the permeate suction pipe 30 communicating with the flow path gap, and stored in the permeate tank 35 via the permeate collection pipe 33 . At that time, between the membrane modules 23, the digested water 3
9 is generated, and this upward flow causes the sludge adhering to the filtration membrane 29 to separate from the filtration membrane 29, thereby preventing the filtration membrane 29 from clogging.

When the membrane module 23 performs solid-liquid separation of the digested water 39, the filtration membranes 29 on both sides of the membrane support net 28
Although it is sucked inward by the suction force, it is held by the membrane support net 28, so the membrane support net 2 is placed between the two male membranes 29.
8, the flow path gap is always maintained over the entire surface of the filtration membrane 29. Therefore, the suction force acts on the entire surface of the filtration membrane 29, and ilJ! A decrease in the effective filtration area of the filtration membrane 29 is prevented, and the filtration efficiency is improved. In addition, filtration [
29 is directly held by the membrane support net 28, which not only simplifies the structure but also reduces the thickness of the membrane module 23. Therefore, the membrane module 23 is small, inexpensive, and easy to handle.

Effects of the Invention As explained above, in the present invention, both sides of the membrane support net are covered with the filtration membrane, and a flow path gap for the permeated liquid is formed between the filtration membranes by the membrane support net. A channel gap is formed, and suction force acts on the entire surface of the filtration membrane. Therefore, the effective filtration area of the filtration membrane is prevented from decreasing, and the filtration efficiency can be improved. In addition, since the filtration membrane is directly held by the membrane support net,
In addition to simplifying the structure, the thickness of the membrane module can also be reduced. Therefore, the membrane module becomes smaller and cheaper;
It also becomes easier to handle.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an activated sludge treatment apparatus showing an embodiment of the present invention, FIG. 2 is a front view of the membrane module in FIG. 1, and FIG. 3 is a sectional view taken along the line ■-■ in FIG. FIG. 4 is an overall configuration diagram showing an example of a conventional activated sludge treatment apparatus. 23... Membrane module, 28... Membrane support net, 2
9...filtration membrane, 30...permeate suction tube, 31...
Slit, 41... Permeated liquid.

Claims (1)

[Claims] 1. A filtration membrane is provided covering both the front and back sides of the membrane support net, a flow path gap for the permeate is formed by the membrane support net between the front and back filtration membranes, and one end edge of the membrane support net is provided on the permeate suction tube. 1. A membrane module for an activated sludge treatment apparatus, characterized in that the membrane module is inserted into a slit in which the flow path is in communication with a permeate suction pipe.