JPH11179398A - Activated sludge processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide activated sludge processing equipment which can make a position of a treated water outlet higher or lower than the level of sludge surface, and does not need special power for filtration. SOLUTION: In activated sludge processing equipment, a membrane module 2 and an air diffusion pipe 4 installed under the membrane module 2 are arranged in an aeration tank 1, a filtrate feed pipe 9 which supplies the purified filtrate to a blow chamber 6 is connected to the secondary side of the membrane module 2, a blow chamber 6 connected to one end of the filtrate feed pipe 9 is provided with a blow pipe 7 which blows gas or liquid into the filtrate supplied from the filtrate feed pipe 9, and a discharge pipe 8 is connected to the blow chamber 6. In this case, the filtrate feed pipe 9 is connected to the secondary side of the membrane module 2 and the blow chamber 6 so as to keep them liquid-tight, gas or liquid is blown from a spout hole 7a of the blow pipe 7 into the filtrate in the blow chamber 6, and the gas or liquid blown into the filtrate is discharged from the discharge pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an activated sludge treatment apparatus for performing solid-liquid separation using a separation membrane in water treatment or the like.

[0002]

2. Description of the Related Art Separation membranes have been used in recent years in the filtration process of purified water or urban wastewater such as human waste and sewage, and organic wastewater such as factories from the viewpoint of good treated water quality and volumetric efficiency. Have been used. The membrane separation devices used in these systems usually have a problem in that a running cost for operating the separation membrane is required because filtration is performed between a water tank and a membrane module through power such as a supply pump. In contrast, Japanese Patent Laid-Open No. 5-1
As disclosed in Japanese Patent No. 68864, there has been proposed a system in which a filtered water outlet is provided at a position lower than the water surface to form a siphon and perform filtration. In this case, in order to prevent the siphon from breaking, it is necessary to provide a vacuum pump or the like as a means for removing bubbles mixed in the filtrate, and there has been a problem that the apparatus becomes complicated. Also, JP-A-6-218237 and JP-A-7-132
As disclosed in Japanese Patent Publication No. 213, a method of performing filtration by a head difference without using mechanical power is also used. However, when filtration is performed using only the head difference, the filtrate outlet must be provided at a position lower than the liquid level of the liquid to be treated, and there is a problem in that the configuration and arrangement of the apparatus are restricted.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages, and does not require a vacuum pump or the like for filtration, has no restriction on the position of the filtrate outlet, and has an aeration tank. It is an object of the present invention to provide an activated sludge treatment apparatus which does not require special processing on a main body and can perform solid-liquid separation at low cost.

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a membrane module and an aeration tube disposed below the membrane module inside an aeration tank, and to supply a filtrate purified by the membrane module to a blowing chamber. A filtrate supply pipe for supplying the filtrate is connected to the secondary side of the membrane module, and a blowing chamber connected to one end of the filtrate supply pipe has a blow pipe for blowing gas or liquid into the filtrate supplied from the filtrate supply pipe, An activated sludge treatment device in which a discharge pipe is connected to the blowing chamber, wherein the filtrate supply pipe connects the secondary side of the membrane module and the blowing chamber in a state where the sludge is kept liquid-tight with the sludge. In the activated sludge treatment apparatus, gas or liquid is blown into a filtrate in a blowing chamber from a discharge hole of a blow pipe, and the blown gas or liquid and the filtrate are discharged from a discharge pipe.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but it should be understood that the present invention is not construed as being limited thereto. 1 to 4 are schematic diagrams showing an embodiment of the activated sludge treatment apparatus of the present invention, and FIG. 7 is a diagram showing an example of a hollow fiber membrane module as a membrane module. An example of the activated sludge treatment apparatus of the present invention includes a membrane module 2 and an aeration tube 4 disposed below the membrane module 2 inside the aeration tank 1, and blows the filtrate purified by the membrane module 2. A filtrate supply pipe 9 for supplying to the chamber 6 is connected to the secondary side of the membrane module 2, and a blowing chamber 6 connected to one end of the filtrate supply pipe 9 supplies gas or liquid to the filtrate supplied from the filtrate supply pipe 9. The activated sludge treatment apparatus includes a blowing pipe 7 for blowing, and a discharge pipe 8 is connected to the blowing chamber 7. The filtrate supply pipe 9 connects the secondary side of the membrane module 2 and the blowing chamber 6. In addition to connecting the sludge with the sludge in a liquid-tight manner, a gas or a liquid is blown into the filtrate in the blow-in chamber 6 from a discharge hole 7a at the tip of the blow-pipe 7, and the blown gas or liquid and the filtrate are discharged. 8 to be released It is those who are.

The aeration tank 1 is filled with sewage to be treated (liquid to be treated). The injected sewage is subjected to biological treatment in an aeration tank 1 by activated sludge to decompose water-soluble components such as BOD and COD. The sludge 1a subjected to the biological treatment is solid-liquid separated by the membrane module 2 immersed in the aeration tank 1. Further, an air diffuser 4 is disposed below the membrane module 2, air is supplied to the air diffuser 4 by a blower 5, bubbling is performed, and filtration is performed while cleaning the membrane surface of the separation membrane of the membrane module 2. Will be Examples of the diffuser tube 4 include a hollow tube having many diffuser holes having a diameter of about 0.5 to 20 mm.

[0007] The filtrate filtered by the membrane module 2 is supplied into the blowing chamber 6 from a filtrate supply pipe 9 connected to and connected to the secondary side of the membrane module 2. The filtrate supply pipe 9 is connected between the secondary side (filtrate side) of the membrane module 2 and the blowing chamber 6 while keeping the liquid tight and shut off from the outside air. Therefore, the sludge 1 a and the air are not supplied from the filtrate supply pipe 9 into the blowing chamber 6.

The blowing chamber 6 is for blowing gas or liquid into the filtrate supplied from the filtrate supply pipe 9. For this purpose, the blowing chamber 6 has a blowing pipe 7 for blowing gas or liquid into the filtrate. The shape of the blowing chamber 6 may be a box shape or a cylindrical shape as shown in FIGS. 1 to 5, a hollow disk shape as shown in FIG. 6, or a spherical or conical shape. May be used, and the shape is not particularly limited.

A gas or a liquid is blown toward the discharge pipe 8 in the filtrate in the blow chamber 6 from the discharge hole 7 a at the tip of the blow pipe 7. When a gas or a liquid is blown vigorously from the ejection hole 7a, the filtrate around the ejection hole 7a is discharged together with the discharge tube 8a.
, And the filtrate supply pipe 9 tightly connects the secondary side of the membrane module 2 to the blowing chamber 6, so that the pressure in the blowing chamber 6 decreases. For this reason, in the membrane module 2 connected to the blowing chamber 6, a pressure difference occurs between the primary side (the side where the sludge 1a is introduced into the membrane module for solid-liquid separation) and the secondary side. Then, the filtrate filtered by the membrane module 2 passes through the filtrate supply pipe 9 and moves into the blowing chamber 6 from the connection port 6 a with the filtrate supply pipe 9. Therefore, no power for filtration, such as a vacuum pump, is required.

The filtrate into which the gas or liquid has been blown is discharged together with the blown gas or liquid from the discharge pipe 8 connected to the blowing chamber 6 to the outside of the activated sludge treatment apparatus.
Thus, the filtration is performed in the membrane module 2, and the purified filtrate can be continuously taken out of the activated sludge treatment apparatus.

The hole area of the ejection hole 7a at the tip of the blowing pipe 7 is
As shown in FIG. 1, FIG. 3, FIG. 5, and FIG. 6, when the area is smaller than the hole area of the blow-pipe main body, the gas or liquid gushes vigorously from the blow-out hole 7a. It is preferred. If the hole area of the ejection hole 7a is smaller than the hole area of the main body of the blowing pipe 7, preferably １ ／ or less, the gas or liquid ejection speed increases, and the degree of pressure reduction in the blowing chamber 6 increases. . Further, when the hole area of the discharge pipe 8 into which the filtrate and the blown gas or liquid flows is equal to or smaller than the hole area of the ejection hole 7a, the resistance to the discharge of the gas or liquid becomes large, and the inside of the blow chamber 6 becomes large. It is difficult to increase the degree of decompression. For this reason, it is preferable that the hole area of the discharge tube 8 is larger than the hole area of the ejection hole 7a, and it is particularly preferable that the hole area be 1.5 times or more the ejection hole 7a. As shown in FIG. 3, FIG. 5, and FIG. 6, if the tip of the blowing pipe 7 is gradually reduced in diameter to form a nozzle, it is easy to blow out gas or liquid from the blowing hole 7a in a vigorous and stable manner. Further, there is an advantage that the pressure loss can be reduced as compared with the case where the diameter is sharply reduced.

In the present invention, the installation position of the blowing chamber 6 is not particularly limited, and may be inside the aeration tank 1 as shown in FIG. 1 or as shown in FIGS. It may be outside the tank 1.

The blowing chamber 6 can be installed at a position higher than the water surface of the aeration tank 1 as shown in FIG. 2 or at a lower position as shown in FIGS. But,
If the position of the connection port 6a between the filtrate supply pipe 9 and the blowing chamber 6 is lower than the water surface of the sludge in the aeration tank 1, a head difference from the water surface occurs, and the pressure in the blowing chamber 6 is more easily reduced. preferable. Therefore, it is preferable that the position of the connection port 6a be lower than the water surface of the aeration tank 1.

A liquid or a gas can be blown from the ejection hole 7a, and the type thereof is not limited, and any type can be used. When a liquid is used, for example, as shown in FIG. 4, a part of the filtrate in the filtrate storage tank 11 for storing the removed filtrate may be circulated using the filtrate circulation pump 10. Tap water may be spouted instead of the filtrate. When a gas is used, a gas cylinder or the like may be used, or air may be sent using a blower. However, in the case of activated sludge treatment, a blower for diffusing air from the diffuser pipe 4 disposed below the membrane module is indispensable.
As shown in Nos. 1 to 3, it is preferable to use a part of the air supplied from the blower 5 as the gas blown from the ejection holes, because it is the simplest in terms of equipment and the energy cost is low. That is, it is preferable that the gas supply source to the air diffuser 4 and the gas supply source to the blowing chamber 6 be the same.

In the present invention, the filtration flow rate of the separation membrane can be adjusted by changing the amount of liquid or gas blown into the blowing chamber 6. That is, as the blowing amount is increased and the force is increased, the degree of pressure reduction in the blowing chamber 6 increases, and the filtration flow rate increases.

As the separation membrane used for the membrane module 2, any one such as a flat membrane, a bag state, a tube state, and a hollow fiber membrane can be used, and the material is not limited at all. Cellulose, polyolefin, polysulfone, polyvinylidene fluoride (PVD
F), polytetrafluoroethylene (PTFE), ceramic and the like. The pore size of the membrane can be arbitrarily set as long as it does not hinder solid-liquid separation.

If a hollow fiber membrane module is used as the membrane module 2, solid-liquid separation can be performed with high precision and at a high flow rate. As a hollow fiber membrane module, as shown in FIG. 7, a hollow fiber membrane 18 made of a knitted fabric using hollow fibers as weft yarns.
Is preferably fixed with a synthetic resin such that the shape of the cross section perpendicular to the hollow fiber membrane 18 is elongated and substantially rectangular while keeping the ends in an open state. In the hollow fiber membrane module shown in FIG. 7, the end of the hollow fiber membrane 18 fixed with a synthetic resin so as to have a rectangular cross section is inserted into the rectangular slit of the tubular support 20, and fixed with the resin. I have.
In this case, the end of each hollow fiber opens into the internal flow path of the tubular support 20. The outer diameter of the hollow fiber is 20 to 2000 μm, and the pore diameter is. It is preferable that the porosity is 0.01 to 1 μm, the porosity is 20 to 90%, and the thickness of the hollow fiber membrane is 5 to 300 μm. The filtrate supply pipe 9 is connected to the tubular support 20 in communication with the internal flow path from which the purified filtrate is taken out.

Next, a preferred embodiment of the activated sludge treatment apparatus of the present invention will be described with reference to FIG. 3. A membrane module 2 and a diffuser 4 disposed below the membrane module 2 are provided in the aeration tank 1. At the same time, a filtrate supply pipe 9 for supplying the filtrate purified by the membrane module 2 to the blowing chamber 6 is connected to the secondary side of the membrane module 2, and the blowing chamber 6 connected to one end of the filtrate supply pipe 9 is connected to the filtrate supply pipe 9. A blowing pipe 7 for blowing gas into the filtrate supplied from the pipe 9 is provided.
Is connected to the activated sludge treatment apparatus, and the filtrate supply pipe 9 connects the secondary side of the membrane module 2 and the blowing chamber 6 to the sludge 1a.
And the liquid is kept in a liquid-tight state, and gas is blown into the filtrate in the blowing chamber 6 toward the discharge pipe from the discharge hole 7 a of the blow pipe 6, and the blown gas and the filtrate are discharged from the discharge pipe 8. This is an activated sludge treatment apparatus in which the inside of the blowing chamber 6 is depressurized with respect to the primary side of the membrane module 2 and the sludge 1 a is filtered by the membrane module 2. The connection port 6a is provided at a position lower than the water level of the sludge in the aeration tank 1, and the hole area of the ejection hole 7a is smaller than that of the main body of the blow-in pipe 7, and the hole area of the discharge pipe 8 is reduced to the hole area of the discharge hole 7a. This is an activated sludge treatment apparatus in which the gas supply source to the air diffuser 4 and the gas supply source to the blowing chamber 6 are the same 1.5 times or more.

Next, a sludge treatment method using the activated sludge treatment apparatus of the above embodiment will be described with reference to FIG. 3 and FIG. 7. Sewage is introduced into the aeration tank 1, and And air is blown into the sludge 1a to purify the sludge 1a by biological treatment and perform the membrane cleaning of the hollow fiber membrane module 2 with the diffused air. on the other hand,
The air whose flow rate has been adjusted by the flow rate controller 13 is supplied to the blowing pipe 7, and the air in the blowing chamber 6 is vigorously blown into the filtrate in the blowing chamber 6 from the ejection hole 7 a. As described above, the sludge 1a is separated into solid and liquid by the hollow fiber membrane 18 of the hollow fiber membrane module and purified to become a filtrate. The filtrate passes through the hollow of the hollow fiber to reach the internal channel, and the filtrate flows from the internal channel to the filtrate. Air is blown into the blowing chamber 6 through the supply pipe 9 and the connection port 6a, and air is blown in the blowing chamber 6, and the filtrate blown with the air passes through the discharge pipe 8 together with the blown air to the outside of the activated sludge treatment apparatus. To be released.

[0020]

As described above, the activated sludge treatment apparatus of the present invention is an activated sludge treatment apparatus for filtering sludge by reducing the pressure in the inlet chamber to the primary side of the membrane module. No special power, such as a vacuum pump, is required. In addition, the treated water outlet, that is, the position of the discharge pipe, can be installed at any position higher or lower than the aeration tank. No special processing is required for the aeration tank body, and the existing aeration tank is modified. It is also easy to obtain the activated sludge treatment apparatus of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an activated sludge treatment apparatus of the present invention.

FIG. 2 is a schematic diagram showing another example of the activated sludge treatment apparatus of the present invention.

FIG. 3 is a schematic diagram showing another example of the activated sludge treatment device of the present invention.

FIG. 4 is a schematic view showing another example of the activated sludge treatment apparatus of the present invention.

FIG. 5 is a schematic view showing an example of a blowing chamber.

FIG. 6 is a schematic view showing another example of the blowing chamber.

FIG. 7 is a partially cutaway perspective view showing an example of a membrane module.

[Explanation of symbols]

1. Aeration tank, 1a, sludge, 2, membrane module, 4
..Aspirator tube, 5.Blower, 6.Blow-in room, 6a
Connection port, 7 ··· Inlet pipe, 7a ··· Outlet, 8 ··· Discharge pipe, 9 ··· Filtrate supply pipe, 10 ··· Filtrate circulation pump, 11
..Filtrate storage tank, 13 flow regulator, 18 hollow fiber membrane, 20 tubular support

Claims (6)

[Claims] Claims: 1. An aeration tank having a membrane module and an air diffuser disposed below the membrane module,
A filtrate supply pipe for supplying a filtrate purified by the membrane module to a blowing chamber is connected to a secondary side of the membrane module,
The blowing chamber connected to one end of the filtrate supply pipe includes a blowing pipe for blowing gas or liquid into the filtrate supplied from the filtrate supply pipe, and the blowing chamber is connected to a discharge pipe. The filtrate supply pipe connects the secondary side of the membrane module and the blowing chamber in a state of maintaining liquid tightness with sludge, and gas or liquid is blown into the filtrate in the blowing chamber from the outlet of the blowing pipe. An activated sludge treatment apparatus in which the blown gas or liquid and the filtrate are discharged from a discharge pipe. 2. A connection port between the filtrate supply pipe and the blowing chamber is provided at a position lower than the water level of the sludge in the aeration tank.
The activated sludge treatment apparatus according to the above. 3. The activated sludge treatment apparatus according to claim 1, wherein a hole area of the ejection hole is set to be equal to or less than a half of a hole area of the blow-pipe main body. 4. The hole area of the discharge tube is defined as 1.
The activated sludge treatment apparatus according to any one of claims 1 to 3, wherein the treatment time is 5 times or more. 5. The gas supply source to the air diffuser and the gas supply source to the blowing chamber are the same.
An activated sludge treatment apparatus according to any one of claims 1 to 4. 6. A membrane module comprising a hollow fiber membrane made of a knitted woven fabric having hollow fibers as weft yarns, while maintaining an end of the hollow fiber membrane in an open state, wherein a cross section perpendicular to the hollow fiber membrane has an elongated substantially rectangular shape. The activated sludge treatment apparatus according to any one of claims 1 to 5, wherein the hollow fiber membrane module is fixed with a synthetic resin.