JPH11309473A - Septic tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to use a common aeration tank even if the number of persons using the tank is different and a sewage quantity is different by providing a water quantity controlling means controlling the sewage quantity in the aeration tank and a height controlling means keeping the distance between a sewage surface and an upper end of a membrane module almost constant. SOLUTION: In the septic tank, a membrane holding part 5 is provided in the aeration tank 1, to which the sewage 2 is made to flow and plural membrane modules 3 immersed in the sewage 2 and filter the sewage 2 are held side by side. An air diffusing pipe 4 supplying a gas for aeration between the membrane modules 3 is disposed under the membrane modules 3. Then, the water quantity controlling means controlling the sewage quantity in the aeration tank 1 and the height controlling means keeping the distance between the sewage surface and the upper end of the membrane module 3 almost constant are provided. The water quantity controlling means based on a water level sensor it used preferably. The height controlling means is constituted with a spacer member 6 inserted in a vertical groove and interposed between a holding plate 7 and the membrane modules 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a septic tank such as a small-sized combined septic tank for home use, and more particularly to a septic tank for separating suspended sludge substances and water by a membrane module disposed in a diffused aeration tank.

[0002]

2. Description of the Related Art Septic tanks such as small-sized combined septic tanks using a membrane separation activated sludge method have been proposed.

In this septic tank, a membrane holding section is provided in an aeration tank into which sewage flows, and a plurality of membrane modules for immersing the sewage in the sewage and filtering the sewage are held in parallel with the membrane holding section. A diffuser tube for supplying aeration gas is provided below the membrane module.

[0004] The membrane module is formed in a substantially flat shape having a filtration membrane on the surface, and a drain port communicating with a drain pipe is formed at an upper end portion. The membrane holding part is formed in the shape of a rectangular tube with upper and lower openings, and is placed on the bottom surface of the aeration tank. A plurality of vertical grooves are formed on the opposing inner surface of the membrane holding unit, and the membrane modules are fitted in the opposing vertical grooves and are disposed vertically at substantially constant intervals, and float on the bottom of the aeration tank. Held in state. In addition, a diffuser pipe that blows out and supplies aeration gas between the membrane modules is provided below the membrane module.

[0005] In such a purification tank, sewage in the aeration tank is aerated by an aeration gas blown out from a diffuser pipe to be purified. Further, the sewage is finely filtered by a filtration membrane of the membrane module to become purified water, and the purified water is discharged from a drain port of the membrane module to a drain pipe. The sludge in the sewage and the purified water can be precisely separated at high speed using the membrane module, and the adhering sludge on the membrane surface of the membrane module is appropriately removed by the aeration gas from the air diffuser.

[0006]

However, in the above-mentioned conventional septic tank, it is necessary to increase the amount of sewage in the aeration tank and set the amount of activated sludge appropriately as the amount of sewage to be treated increases. Therefore, there is a problem that the size of the aeration tank must be distinguished, and a number of aeration tanks having different sizes must be prepared.

Further, even if a large aeration tank is used and the amount of sewage in the aeration tank is increased so that the number of occupants is different, if the number of occupants is small, the amount of sewage flowing into the aeration tank is small. The activity of the wastewater is low, and the wastewater cannot be treated efficiently.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a septic tank that can use a common aeration tank even when the number of users is different and the amount of sewage is different. .

[0009]

In order to achieve the above object, the invention according to claim 1 is directed to an aeration tank 1 into which sewage 2 flows.
A plurality of membrane modules 3 that are immersed in the sewage 2 and filter the sewage 2 are provided side by side in the membrane holding section 5, and an aeration gas 11 is supplied between the membrane modules 3. In a septic tank in which the air diffuser 4 is disposed below the membrane module 3, a water amount adjusting means for adjusting the amount of sewage in the aeration tank 1, and a height adjustment for making the distance between the sewage surface and the upper end of the membrane module 3 substantially constant. And means are provided.

In such a septic tank, the amount of sewage varies depending on the number of users. As the amount of sewage increases, the amount of sewage in the aeration tank 1 is increased by the water amount adjusting means, and activated sludge suitable for sewage treatment is increased. While maintaining the amount, the membrane module 3 is positioned at a high position in the sewage 2 by the height adjustment means, and the aeration gas 1 rising between the membrane modules 3
1 is generated from the bottom in the sewage 2 to the water surface above the membrane module 3 and the aeration gas 11
The wastewater 2 is distributed throughout the entire area of the wastewater 2 to efficiently perform the decomposition treatment of the wastewater 2 by the activated sludge.

According to a second aspect of the present invention, in the first aspect of the present invention, a spacer member 6 for supporting the membrane module 3 is detachably provided on the membrane holding portion 5, and the spacer member 6 is provided with a height adjusting means. The feature is that it becomes.

In such a septic tank, a spacer member 6 having a height that increases as the amount of sewage increases is used.
By supporting the membrane module 3 on the membrane holding unit 5 through the, the distance between the water surface of the sewage 2 and the upper end of the membrane module 3 is made substantially constant.

The invention according to claim 3 is characterized in that, in the invention according to claim 2, a spacer member 6 is detachably provided at the lower end of the membrane module 3.

In such a septic tank, by taking out the membrane module 3 held by the membrane holding section 5, the spacer member 6 provided at the lower end of the membrane module 3 can be taken out at the same time.

According to a fourth aspect of the present invention, in the second aspect, the spacer member 6 is formed in a pin shape.
A pin hole 1 for detachably inserting and holding the spacer member 6
4 is provided in the film holding unit 5.

In such a septic tank, even if the membrane module 3 is not completely removed from the membrane holder 5, the pin-shaped spacer member 6 inserted into the pin hole 14 is pulled out from the pin hole 14, and the pins having different heights are removed. The height of the membrane module 3 can be adjusted by inserting the spacer member 6 into the hole 14.

The invention according to claim 5 is characterized in that, in the inventions according to claims 2 to 4, a standing wall piece is detachably provided at the upper end of the film holding portion 5.

In such a septic tank, the circulating flow rising between the membrane modules 3 by the aeration gas 11 rises along the vertical wall piece without being disturbed at the upper end of the membrane module 3, and smoothly rotates at the upper end of the vertical wall piece.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a septic tank according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a longitudinal sectional view showing a septic tank according to an embodiment of the present invention. FIG.
(B) shows when the amount of sewage is large. FIG.
FIG. 2 is a perspective view showing a main part of the septic tank according to the first embodiment. FIG. 3 is an explanatory diagram showing the entire configuration of the septic tank according to the first embodiment.

As shown in FIGS. 1 to 3, this septic tank is provided with a membrane holding section 5 in an aeration tank 1 into which sewage 2 flows.
A plurality of membrane modules 3 that are immersed in the sewage 2 and filter the sewage 2 are juxtaposed and held in the membrane holding unit 5.
A diffuser pipe 4 for supplying an aeration gas 11 therebetween is disposed below the membrane module 3. Further, there are provided a water amount adjusting means for adjusting the amount of sewage in the aeration tank 1 and a height adjusting means for making the distance between the sewage surface and the upper end of the membrane module 3 substantially constant.

In the purification tank, the outer tank 20 is divided into three tanks by a partition plate.
And the remaining one tank is an aeration tank 1. The sedimentation / separation tank 21 roughly separates the sludge from the supernatant by causing the sludge contained in the sewage 2 flowing from the inlet 23 to settle on the bottom surface of the sedimentation / separation tank 21. The tank 21 is used continuously, and the precipitation separation treatment is performed in two stages. Then, the supernatant containing the sludge roughly separated in the sedimentation separation tank 21 is sent into the aeration tank 1, and the supernatant is precision-separated into sludge and water as the wastewater 2 in the aeration tank 1. The transfer of the supernatant liquid between each tank is performed by a transfer pump 2 installed in each tank.
5 and a transfer pipe 26 connected to the transfer pump 25. An opening is provided above each tank, and a removable septic tank lid is provided at the opening.

The membrane holding section 5 is formed in a substantially rectangular cylindrical shape having openings on the upper and lower sides, and is supported on the bottom surface of the main body of the aeration tank 1 via legs. A plurality of vertical grooves 8 on the opposite surface of the film holding unit 5;
The holding plate 7 for closing the lower opening of the lower end of the vertical groove 8 is formed. The longitudinal grooves 8 removably fit both ends of the plurality of membrane modules 3 so that the membrane modules 3 are vertically arranged at regular intervals, and the holding plate 7 contacts the lower end of the membrane module 3. As a result, the membrane module 3 is held in a state of floating above the bottom surface of the main body of the aeration tank 1.

The membrane module 3 is formed by attaching a filtration membrane 3a having a myriad of fine holes on both sides of a substantially rectangular frame material. The space between the filtration membrane 3a and the frame member is communicated with the external space by a drain passage, and a drain port 29 communicating with the drain pipe 28 is provided at an opening of the drain passage on the outside space side. Then, only water from the sewage 2 around the membrane module 3 passes through the micropores to be purified water by the drain pump 27 provided in the drain pipe 28, and the purified water is drained through the drain passage and the discharge port 24. The water is introduced into the pipe 28 and sent out from the outlet.

Further, a plurality of openings are arranged in a horizontal direction at the lower end of the facing surface of the membrane holding portion 5 where the vertical groove 8 is not formed, and a diffuser pipe for sending gas between the membrane modules 3 outside this opening. 4 are fixedly connected to each other. Each branch pipe communicates with one diffuser pipe 4 below the membrane holding unit 5 and is further connected to a diffuser pump 30. The gas is blown out from the opening of the membrane holding part 5 into the sewage 2 in the lower part of the membrane holding part 5 through the air diffusion pipe 4 and the branch pipe by the air diffuser pump 30.

The means for adjusting the amount of water is preferably a means based on a water level sensor. The water level sensor (not shown) detects the water level of the sewage 2 in the main body of the aeration tank 1, that is, the amount of sewage, and is disposed inside the main body of the aeration tank 1. The detection signal of the water level sensor is sent to a pump control device (not shown) that controls the operations of the transfer pump 25 and the drain pump 27 for flowing the sewage 2 into the aeration tank 1 body. The pump control device receives the detection signal of the water level sensor and controls the transfer pump 25 so as to maintain the sewage 2 in the aeration tank 1 at a predetermined amount.
And the operation of the drainage pump 27 is controlled.

The height adjusting means includes a spacer member 6 inserted in the vertical groove and interposed between the holding plate 7 and the membrane module 3.
Is formed by The spacer member 6 is formed in a rectangular plate shape having substantially the same shape as the planar view membrane module 3 and different heights. Then, a plurality of spacer members 6 having different heights are prepared, and the spacer members 6 having a height such that the distance between the sewage surface and the upper end of the membrane module 3 is substantially constant.
Is inserted into the longitudinal groove.

This septic tank is installed as follows.
First, the membrane holding unit 5 is put into the aeration tank 1 main body from the upper end opening thereof, and is placed on the bottom of the aeration tank 1 main body via a leg. Next, the ends of the membrane modules 3 are fitted into the vertical grooves 8 of the membrane holding section 5 from above, and are held by the holding plate 7. further,
The air diffuser 4 is inserted into the gap between the inner surface of the aeration tank 1 main body and the outer surface of the membrane holder 5 from above, and the end of the branch pipe of the air diffuser 4 is fixed to the outer opening at the lower end of the membrane holder 5.

In such a purification tank, the sewage 2 in the aeration tank 1 is aerated by the aeration gas blown out from the air diffuser 4 between the membrane modules 3 and purified. Also, by operating the drain pump 27 connected to the drain pipe 28,
The purified sewage 2 is finely filtered by the filtration membrane 3 a of the membrane module 3, and discharged from a drain port 29 of the membrane module 3 to a drain pipe 28. On the other hand, the sludge adhering to the membrane surface of the filtration membrane 3a by the filtration is desorbed from the membrane surface by the upward flow generated by the air lift action of the bubbles of the aeration gas 11 rising between the membrane modules 3. In addition, the sewage 2 is partitioned by the membrane holding unit 5, and causes a circulating flow to rise the gas around the membrane holding unit 5.

Further, the amount of sewage is varied depending on the number of users. As the amount of sewage increases, the amount of sewage in the aeration tank 1 is increased by the water amount adjusting means to secure an appropriate amount of activated sludge for sewage treatment. At the same time, the membrane module 3 is positioned at a high position in the sewage 2 by the height adjusting means, and the circulation by the aeration gas 11 rising between the membrane modules 3 causes the water surface from the bottom in the sewage 2 to above the membrane module 3. Thus, the aeration gas 11 spreads over the entire area of the sewage 2 to efficiently perform the decomposition treatment of the sewage 2 by activated sludge.

Table 1 illustrates a specific example using the same septic tank.

[0032]

[Table 1]

As shown in Table 1, depending on the number of employees, B
The amount of treated sewage in the aeration tank 1 and the number of membranes of the membrane module 3 are set so that the OD sludge load is substantially constant. In this case, the amount of treated sewage is set in proportion to the number of users.
Further, as the amount of treated sewage is larger, the number of membranes of the membrane module 3 is increased to make the filtration amount per membrane module 3 substantially constant.

FIG. 4 is a side view showing height adjusting means different from that used in the septic tank according to the embodiment of the present invention.

As shown in FIG. 4, the height adjusting means
The spacer member 6 is detachably provided at the lower end of the membrane module 3. The spacer member 6 is formed in a rectangular plate shape having substantially the same shape as the planar view membrane module 3 and different heights. Further, a dovetail 13 is formed at the lower end of the membrane module 3, and a convex portion 12 fitted and held in the dovetail 13 is provided at the upper end of the spacer member 6. Then, the dovetail groove 1 is formed until the side surfaces of the membrane module 3 and the spacer member 6 are substantially flush.
The spacer member 6 is held at the lower end of the membrane module 3 by fitting the protrusion 12 into the side of the module 3 from the side.

In such a septic tank, by taking out the membrane module 3 held by the membrane holding section 5, the spacer member 6 provided at the lower end of the membrane module 3 can be taken out at the same time, and the spacer member 6 can be easily replaced.

FIG. 5 is a side view showing height adjusting means different from that used in the septic tank according to the embodiment of the present invention.

As shown in FIG. 5, the height adjusting means
The spacer member 6 is formed as a pin member 15, and a pin hole 14 for detachably inserting and holding the pin member 15 is provided in the film holding section 5. The pin hole 14 is formed in a substantially circular shape, and is formed at an appropriate interval in the vertical direction on the inner surface of the vertical groove. The pin member 15 is formed of a disk-shaped head 15a having a diameter longer than the diameter of the pin hole 14 and a columnar leg 15b having a diameter smaller than the diameter of the pin hole 14. Then, the leg 15b is inserted into the pin hole 14 from the outside of the film holding unit 5 until the head 15a is engaged with the pin hole 14, whereby the pin member 15 is inserted and held in the pin hole 14. In this state, the leg portion 15b is in contact with and supported by the lower end of the membrane module 3, and holds the membrane module 3 in a state of being floated on the holding plate 7. By selecting the pin holes 14 into which the pin members 15 are inserted, the height of the membrane module 3 can be adjusted freely, and the distance between the water surface of the sewage 2 and the upper end of the membrane module 3 can be adjusted to be substantially constant.

In such a septic tank, the pin member 15 inserted into the pin hole 14 is pulled out from the pin hole 14 without completely removing the membrane module 3 from the membrane holding unit 5, and the pin module 14 having a different height is inserted into the pin hole 14. The height of the membrane module 3 can be adjusted by inserting the pin member 15.

It is to be noted that a standing wall piece may be detachably provided at the upper end of the film holding section 5. By adjusting the height of the standing wall piece to the height of the upper end of the membrane module 3, the turbulence of the circulation at the upper end of the membrane module 3 is prevented, and the circulation flows more smoothly.

[0041]

According to the first aspect of the present invention, the amount of sewage varies depending on the number of employees. The greater the amount of sewage, the more the amount of sewage in the aeration tank is increased by the water amount adjusting means, and the more appropriate the sewage treatment is. In addition to ensuring a high amount of activated sludge, the height adjustment means positions the membrane module at a high position in the sewage, and the circulating flow of aeration gas rising between the membrane modules causes the water surface from the bottom in the sewage to above the membrane module. The aeration gas is distributed over the entire area of the sewage, and the sewage decomposition treatment by activated sludge is efficiently performed. Therefore, a common aeration tank can be used even if the number of users is different and the amount of sewage is different.

According to the second aspect of the present invention, the water surface of the sewage and the membrane can be increased by using a spacer member having a height that increases as the amount of sewage increases, and supporting the membrane module on the membrane holding portion via the spacer member. The distance from the upper end of the module is easily made substantially constant.

According to the third aspect of the present invention, by taking out the membrane module held by the membrane holding portion, the spacer member provided at the lower end of the membrane module can be taken out at the same time, and the replacement of the spacer member is easy.

According to the fourth aspect of the present invention, the pin-shaped spacer member inserted into the pin hole is pulled out from the pin hole without completely removing the membrane module from the film holding portion.
The height of the membrane module can be adjusted by inserting spacer members into pin holes of different heights.

According to the fifth aspect of the present invention, the circulating flow rising between the membrane modules by the aeration gas rises along the standing wall piece without being disturbed at the upper end of the membrane module, and smoothly turns around the upper end of the standing wall piece. Therefore, the activated sludge can be used more efficiently.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a septic tank according to an embodiment of the present invention, wherein (a) shows a case where the amount of sewage is small, and (b) shows a case where the amount of sewage is large.

FIG. 2 is a perspective view showing a main part of the septic tank according to the first embodiment.

FIG. 3 is an explanatory view showing the entire configuration of the septic tank according to the first embodiment.

FIG. 4 is a side view showing height adjusting means different from that used in the septic tank according to the embodiment of the present invention.

FIG. 5 is a side view showing a height adjusting means different from that used in the septic tank according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aeration tank 2 Sewage 3 Membrane module 3a Filtration membrane 4 Air diffuser 5 Membrane holding part 6 Spacer member 7 Holding plate 8 Vertical groove part 9 Side wall 11 Aeration gas 12 Convex part 13 Dovetail groove 14 Pin hole 15 Pin member 15a Head 15b Leg Part 20 Outer tank 21 Sedimentation separation tank 23 Inlet 24 Outlet 25 Transfer pump 26 Transfer pipe 27 Drain pump 28 Drain pipe 29 Drain port 30 Aeration pipe pump

Continuing on the front page (72) Inventor Shin Shin, 1048, Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. (72) Inventor Hiroshi Kano 1048, Oji, Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Invention Person Keiyoshi Nakaoka 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Shigeyuki Yamaguchi 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd.

Claims (5)

[Claims] A membrane holding section is provided in an aeration tank into which sewage flows, and a plurality of membrane modules for immersing the sewage in the sewage and filtering the sewage are held in parallel with the membrane holding section. In a septic tank provided with a diffuser pipe for supplying gas below the membrane module, a water amount adjusting means for adjusting the amount of sewage in the aeration tank, and a height adjustment for making the distance between the sewage surface and the upper end of the membrane module substantially constant. And a means for providing a septic tank. 2. The septic tank according to claim 1, wherein a spacer member for supporting the membrane module is detachably provided on the membrane holding portion, and the spacer member serves as height adjusting means. 3. The septic tank according to claim 2, wherein a spacer member is detachably provided at a lower end of the membrane module. 4. The septic tank according to claim 2, wherein the spacer member is formed in a pin shape, and a pin hole for detachably inserting and holding the spacer member is provided in the membrane holding portion. 5. The septic tank according to claim 2, wherein a standing wall piece is detachably provided at an upper end of the membrane holding unit.