JPH0871585A - Aeration tank - Google Patents

Abstract

PURPOSE: To provide an aeration tank unnecessary for taking out an air diffusion pipe to the outside when the excessive biological sludge bonded to the air diffusion orifices of the air diffusion pipe is removed. CONSTITUTION: The blow pipe 34 draining the water in an aeration tank is connected to the air supply pipe 30 sending air to an air diffusion pipe 33 at an arbitrary place where the head pressure of the water in an aeration tank main body 20 is applied and a valve 35 is provided in the pipeline of the blow pipe 34. The water in the aeration tank main body 30 is allowed to flow backward through the air diffusion pipe 33 and the blow pipe 34 by opening the valve 35 and the deposited matter in the periphery of air diffusion orifices 36 is removed by the back flow water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aeration tank for biologically treating water to be treated containing organic substances and / or nitrogen components such as ammonia nitrogen and organic nitrogen, and particularly to oxygen such as air in the tank. The present invention relates to an aeration tank capable of efficiently eliminating clogging of a diffuser for supplying a contained gas.

[0002]

2. Description of the Related Art As one of the means for removing organic substances (BOD components) contained in general industrial wastewater and domestic wastewater or nitrifying ammonia nitrogen, organisms such as an activated sludge method and a fixed bed catalytic oxidation method are used. Aeration tanks based on biological treatment are widely used. FIG. 2 shows an example of a conventional fixed bed catalytic oxidation type aeration tank. In the figure, 1 is an aeration tank main body, 2 is an eye plate attached to a lower portion in the aeration tank main body 1, and 3 is the eye plate. 2 is a filler filled on the upper surface of the filler 2, and aerobic microorganisms are allowed to grow on the surface or inside of the filler 3.

Reference numeral 4 denotes a treated water supply pipe for supplying industrial wastewater containing domestic substances or domestic wastewater (hereinafter referred to as treated water) into the aeration tank main body 1 by a pump 5. Reference numeral 6 denotes a treated water header pipe forming a part of the treated water supply pipe 4, and the treated water is distributed to the plurality of treated water supply branch pipes 4A, 4A ... Through the header pipe 6. Then, the gas is evenly supplied to the lower part of the eye plate 2 attached inside the aeration tank body 1.

Reference numeral 7 is an air supply pipe for sending air as an oxygen-containing gas by a blower 8 to a lower portion in the aeration tank body 1. Reference numeral 9 denotes an air header pipe forming a part of the air supply pipe 7, and the air is distributed to the plurality of air supply branch pipes 7A, 7A ... Through the header pipe 9 and each air supply branch pipe 7A. , 7A ... Evenly distributed in the lower part of the aeration tank main body 1 through a large number of air diffusers 11 having a diameter of about 2 to 10 mm formed in the air diffusers 10, 10 ... Supplied.

Reference numeral 12 is a trough formed on the upper peripheral edge of the aeration tank main body 1. The treated water that has risen in the layer of the filling material 3 is collected by this trough 12 and is passed through the treated water discharge pipe 13 to the aeration tank main body. 1 is discharged to the outside. Further, 14 is a blow pipe for the in-tank water connected to the treated water header pipe 6 forming a part of the treated water supply pipe 4, and 15 is the blow pipe 1
It is a valve attached in the conduit of No. 4.

In the operation of the above-described conventional aeration tank, first, the pump 5 is driven to supply the treated water through the treated water supply pipe 4, the treated water header pipe 6 and the treated water supply branch pipe 4A. Supply to the lower part in the aeration tank body 1. On the other hand, at the same time, the blower 8 is operated to supply air through the air supply pipe 7, the air header pipe 9, and the air supply branch pipe 7A to the aeration tank from the aeration pipe 10 which is piped in the lower portion of the aeration tank main body 1. Supply into the main body 1. Then, the water to be treated passes through the eye plate 2 while being mixed with air, and while the layer of the packing material 3 is rising, the aerobic microorganisms that have grown on the packing material 3 biologically oxidize the BOD component, for example. The treated water from which the BOD component has been removed is discharged to the outside of the aeration tank main body 1 through the trough 12 and the treated water discharge pipe 13.

If the above-mentioned treatment operation is continued, excess biological sludge and suspended substances will gradually adhere between the gaps between the fillers 1 and the treatment efficiency will decrease. To periodically backwash the layer of filler 3,
Remove suspended solids and excess biological sludge. In addition to the above backwash, the following operation may be performed depending on the case. That is, the operation of the pump 5 is stopped, the valve 15 is opened, and the water in the tank is made to flow back through the treated water supply pipe 4 by the action of the head pressure of the water in the aeration tank main body 1, and the blow pipe It blows to the outside of the aeration tank body 1 together with the surplus biological sludge existing near the bottom in the tank body 1 through 14.

In this way, in the layer of the filler 1 and the tank body 1
The surplus biological sludge accumulated on the bottom of the aeration tank is discharged to the outside of the aeration tank main body 1. However, as the above-described processing operation and backwash operation are continued, the peripheral portion of the air diffusion pipe 10, particularly the air diffusion port 11 Excess biological sludge and scale components such as calcium carbonate also adhere to the surroundings, gradually closing the air diffuser 11. Excess biological sludge, calcium carbonate, etc. adhering to the periphery of the air diffuser 11 formed in the air diffuser 10 can be removed even by performing the above-mentioned backwashing or blowing operation of water in the tank through the treated water supply pipe 4. I can't. Therefore, conventionally, the water in the aeration tank main body 1 is once extracted through the treated water supply pipe 4 and the blow pipe 14, and then the air supply branch pipe 7A and the air diffuser pipe 10 are used.
Remove the flange 16 that connects the
0 was pulled out, the deposits around the air diffuser 11 were cleaned and removed, and then the air diffuser 10 was set in the tank body 1 again and connected to the air supply branch pipe 7 via the flange 16.

[0009]

As described above, in the conventional aeration tank, the air diffuser is taken out from the inside of the tank body in order to prevent clogging of the air diffuser for supplying air into the aeration tank. . Therefore, the operation of the apparatus must be stopped during this work, and there is a big problem that it takes a lot of time and labor to take out and reset the air diffuser. Therefore, the present invention eliminates the disadvantages of the conventional aeration tank described above, it is not necessary to take out any air diffuser pipe out of the tank in removing excess biological sludge attached to the air diffuser,
By effectively utilizing the head pressure of the water in the tank to backflow the water in the tank into the diffuser pipe, it became possible to smoothly discharge the excess biological sludge attached to the vicinity of the diffuser outside the tank. It is intended to provide an aeration tank.

[0010]

The structure of the present invention for achieving the above object will be described in detail. An air diffuser having a plurality of air diffusers formed of small holes or slits is provided in the lower portion of the tank. At the same time as supplying oxygen-containing gas such as air from the air diffuser into the tank through pipes, water to be treated containing organic substances and / or nitrogen components is put into the tank, and biological treatment is performed in the presence of aerobic microorganisms. In an aeration tank adapted to oxidatively decompose organic substances and / or nitrogen components in the water to be treated, the inside of the tank may be located at any location where the head pressure of the water in the tank is applied to the gas supply pipe for sending the oxygen-containing gas to the diffuser pipe. The aeration tank is characterized in that a blow pipe for draining water is connected and a valve is provided in the pipeline of the blow pipe.

[0011]

The function of the aeration tank of the present invention is as follows.
It is characterized in that a blow pipe for draining water from the tank is connected to a gas supply pipe that sends oxygen-containing gas such as oxygen-enriched air and pure oxygen.The blower is stopped and attached to the blow pipe. When the valve provided is opened, the water in the tank flows back through the diffuser port due to the head pressure of the water in the aeration tank, and further through the diffuser pipe and the blow pipe. The deposits on the periphery are peeled off and discharged together with the backflow water to the outside of the tank. Therefore, according to the aeration tank of the present invention, in order to remove the clogging of the air diffuser,
It is possible to eliminate the conventional problem that the operation of the entire aeration tank has to be stopped for a long time as it is not necessary to take out the air diffuser from the inside of the tank as in the conventional case.

In order to satisfactorily remove the adhering substances around the diffuser port, the head pressure of the water in the tank should be concentrated at the diffuser port of the diffuser pipe, and for that purpose, it should be connected to the treated water supply pipe. It is only necessary to close the valve of the blow tube that is installed, and calcium carbonate and surplus biological sludge adhered to the periphery of the diffuser will be separated by the water in the tank flowing into the diffuser due to the head pressure of the water in the tank, and will flow backward. It becomes water and is discharged well outside the tank. Further, the operation of draining water in the tank through the gas supply pipe as described above may be performed after the air diffuser has been clogged to some extent, but in the sense of preventing clogging, the above operation is performed. It is desirable to do it regularly.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete construction of the aeration tank of the present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a schematic explanatory view showing an embodiment of the aeration tank of the present invention, and 20 in the figure shows an aeration tank main body. Reference numeral 21 is a perforated plate made of a perforated plate provided inside the aeration tank body 20, and 22 is a filler layer filled on the upper surface of the perforated plate 21. Although not particularly shown, the filler layer 22 forms a support material layer made of relatively coarse gravel or crushed stone that does not pass through the eye plate 21 in the lower stage, and fine gravel or crushed stone, spherical particles are formed on the support material layer. It is usually formed by filling a filling material such as ceramics, a honeycomb tube, and a net-like body to a height of 3 to 5 m. Needless to say, the filler forming the filler layer 22 has aerobic microorganisms grown thereon.

Next, 23 is a treated water supply pipe, 24 is a pump for pumping the treated water into the aeration tank main body 20 through the treated water supply pipe 23, and 25 is connected to the treated water supply pipe 23. A treated water header pipe forming a part of the supply pipe 23, 26
Is a blow pipe connected to the treated water header pipe 25, 2
Reference numeral 7 is a valve attached in the conduit of the blow pipe 26. The treated water is evenly supplied to the lower part in the aeration tank body 20 through the plurality of treated water supply branch pipes 28, 28 ... Connected to the treated water header pipe 25. Has become. The plurality of treated water supply branch pipes 28, 28
Needless to say, ... Form a part of the treated water supply pipe 23.

On the other hand, the system for supplying the air as the oxygen-containing gas into the aeration tank main body 20 is a blower 29, an air supply pipe 30 connected to the blower 29, and the air supply connected to the air supply pipe 30. An air header pipe 31 forming a part of the pipe 30, a plurality of air supply branch pipes 32, 32 ... Connected to the air header pipe 31, and tips of the air supply branch pipes 32, 32. And a plurality of air diffusers 33, 33 ... The air supply pipe 30 is temporarily raised above the upper surface of the treated water of the aeration tank body 20 in order to prevent the water to be treated in the aeration tank body 20 from flowing backward toward the blower 29 when the operation of the blower 29 is stopped.

Next, 34 is a blow pipe for draining water in the tank, which is connected to the air header pipe 31 forming a part of the air supply pipe 30, and 35 is attached in the conduit of the blow pipe 34. It is a valve. In the illustrated embodiment, the blow pipe 34 is connected to the air header pipe 31 in this manner, but the connection position of the blow pipe 34 is not limited to this embodiment, and the point is that the water inside the aeration tank main body 20 It can be connected to any position of the air supply pipe 30 as long as the head pressure is applied to the air supply pipe.

In addition, in the figure, 36 is a large number of diffuser ports having a diameter of about 2 to 10 mm formed on the lower side of the diffuser pipe 33, 37 is a drain groove provided below the blow pipes 26 and 34, and 38 is a drainage groove. A treated water discharge trough formed on the upper peripheral edge of the aeration tank main body 20, and a treated water discharge pipe 39 for discharging the treated water in the trough 38 to the outside of the tank main body 20.

Next, an operation example of the aeration tank of the present invention will be described. Supply of the treated water into the aeration tank main body 20 through the treated water supply pipe 23 and air aeration tank main body through the air supply pipe 30. Since the supply to the inside of 20 is almost the same as the case of the above-mentioned conventional example, detailed description will be omitted.

As the biological treatment of the water to be treated in the aeration tank body 20 continues, calcium carbonate, surplus biological sludge and the like gradually adhere to the periphery of the diffuser 36 of the diffuser pipe 33. When the air diffuser 36 becomes clogged, the discharge pressure of the blower 29 that supplies air to the aerobic microorganisms that have grown on the filler layer 22 increases. Therefore, in order to remove this clogging, first, the operation of the blower 29 is stopped, and then the valve 35 attached in the conduit of the blow pipe 34 is opened. At that time, the valve 27 attached to the blow pipe 26 on the treated water supply pipe side is closed.

Then, the head pressure of the in-tank water in the aeration tank main body 20 is applied to the diffuser pipe 33, and the in-tank water enters the diffuser pipe 33 from the narrowed diffuser port 36 to supply the air supply branch pipe. 32,
32, the header pipe 31, and the blow pipe 34 are backflowed and blown into the drain groove 37 from the tip of the blow pipe 34. At that time, the deposits around the air diffuser 36 are gradually separated by the flow of water in the tank that flows back into the air diffuser 33 through the air diffuser 36, and is blown together with the water in the tank.

After backflowing the water in the tank through the blow pipe 34 for a predetermined time, the valve 35 is closed and the blower 29 is operated to operate the air supply header pipe 31 and the air supply branch pipe 32.
The water accumulated inside is pushed back into the aeration tank main body 20.
Then, during normal operation, the discharge pressure of the blower 29 decreases, so that it can be confirmed that the clogging of the air diffuser 36 has been eliminated. In the above-mentioned embodiment, the aeration tank of the fixed bed catalytic oxidation method in which the aeration tank main body is filled with the filler for adhering microorganisms has been described.
The present invention is not limited to this, and can be applied to, for example, an aeration tank for so-called activated sludge treatment in which a filler does not exist in the aeration tank main body.

[0022]

As described above, the aeration tank of the present invention is characterized in that the blow pipe for draining water in the tank is connected to the gas supply pipe for sending the oxygen-containing gas such as air to the diffuser pipe. Yes, there is no need to take the diffuser pipe out of the tank to remove excess biological sludge attached around the diffuser port, and the head water pressure in the tank is effectively used to backflow the tank water into the diffuser pipe. Let
Excessive biological sludge attached around the diffuser can be discharged smoothly outside the tank, eliminating the conventional problem of having to stop the operation of the entire aeration tank for a long time. Is what you can do. In addition, since the water in the tank is made to flow backward by a simple operation of opening the valve attached to the blow pipe to remove the deposits around the diffuser port, it is economically very advantageous.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the aeration tank of the present invention.

FIG. 2 is a schematic explanatory view showing an example of a conventional aeration tank.

[Explanation of symbols]

20: Aeration tank main body 21: Eye plate 22: Filler layer 23: Treated water supply pipe 24: Pump 25: Treated water header pipe 26: Blow pipe 27: Valve 28: Treated water supply branch pipe 29: Blower 30 : Air supply pipe 31: Air header pipe 32: Air supply branch pipe 33: Air diffuser pipe 34: Blow pipe 35: Valve 36: Air diffuser 37: Drain groove

Claims (1)

[Claims] 1. A diffusing pipe having a large number of diffusing ports consisting of small holes or slits is provided in the lower part of the tank, and at the same time oxygen-containing gas such as air is supplied from the diffusing pipe into the tank. In an aeration tank in which water to be treated containing organic matter and / or nitrogen component is placed in the tank and the organic matter and / or nitrogen component in the water to be treated is oxidized and decomposed by biological treatment in the presence of aerobic microorganisms. , A blow pipe for draining the water in the tank is connected to an arbitrary position where the head pressure of the water in the tank is applied to the gas supply pipe for sending the oxygen-containing gas to the air diffuser, and in the conduit of the blow pipe. An aeration tank with a valve attached.