JP2006198478A - Aerator and method for operating aeration tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To diffuse sludge sediment on the bottom part of a tank by cheap means in an overall aeration method. <P>SOLUTION: An air diffuser 10 in the aeration tank 1 is divided into one diffusion part 10b and another diffusion part 10a, and a flexible pipe joint 17 having an on-off valve function is provided through a lateral pipe 11 on the border of both the diffusion parts. Normally, as shown by a solid line, both the diffusing parts 10a and 10b are made into a horizontal state, air is supplied to all diffusion parts to be diffused over the whole area of the tank 1, and the overall aeration is carried out. When the sludge is settled on the bottom part of the tank, one diffusion part 10b is elected as shown by a chain line, air distribution to the diffusion part 10b is cut off by the on-off valve function of the flexible pipe joint 17 due to the election. Thus, air is introduced only into another diffusion part 10a, swirling flow is generated to agitate the sludge settled on the bottom part of the aeration tank. If there is no sludge sediment on the bottom part of the aeration tank 1 (diffuse), one diffusion part 10b is laid down and returned to a horizontal state to transfer to the overall aeration. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the aeration tank in the sewage treatment plant, the aeration tank for the activated sludge method, the aeration tank for the livestock manure storage tank, etc., the aeration is made to be the entire aeration, and the sludge accumulated at the bottom of the tank is stirred smoothly. The present invention relates to an aeration apparatus that diffuses throughout the tank and a method for operating the aeration tank.

An aeration tank in a sewage treatment plant is generally provided with an air diffuser in the tank, diffused from the air diffuser of the air diffuser, and aerated using an aerobic microorganism in the tank. .
As an aeration method in the aeration tank for performing the aerobic treatment, various methods such as a swirling flow method, a full aeration method, and an underwater agitation method are adopted. It has become mainstream.

The above-described swirling flow type aeration method is provided with a diffuser on one side of the aeration tank, diffuses from the diffuser pipe of the diffuser, and creates a swirling flow in the tank by the upward flow caused by the diffused air. The entire area in the tank is stirred and aerated by the swirling flow (see Patent Document 1).
In the aeration method of the entire surface aeration method, an aeration device is installed at the bottom of the aeration tank, and the entire surface of the tank is diffused and aerated from the aeration pipe of the aeration device (see Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 9-276891 JP-A-9-174066

  In addition, some aeration tanks have a higher concentration of manure compared to an aeration tank in a sewage treatment plant and treat the manure by an activated sludge method. In this aeration tank, various types such as the swirling flow method, the entire surface aeration method, and the underwater agitation method are adopted, but similarly, the swirling flow method and the entire surface aeration method become mainstream in the degree of spread. ing.

  Furthermore, by storing livestock manure such as dairy cow urine, the number of coliforms decreases, and further aeration reduces the hydrogen sulfide odor and only the ammonia odor. Similarly, various types of aeration tanks such as the swirling flow type, the entire aeration type, and the underwater agitation type are employed.

The whole surface aeration type has an advantage of high aeration efficiency (treatment efficiency) because it is smoothly diffused throughout the tank, but sludge (sediment such as SS) settles and accumulates at the bottom of the tank. This sludge accumulation needs to be dredged and pulled out because it rots and produces a bad odor (hydrogen sulfide). However, in order to reduce such work, conventionally, the accumulated sludge is stirred and diffused in the tank. Conventionally, the diffusion is performed by mechanical means such as a stirring blade.
In the swirling flow method, the sludge at the bottom of the tank is also agitated by the swirling flow. However, the aeration efficiency is inferior compared to the full aeration type.

For this reason, there is a technique that selectively switches between the whole surface aeration type and the swirling flow type, and diffuses the sludge accumulated at the bottom of the tank by the swirling flow (see Patent Document 1, paragraph 0012, FIG. 3, paragraph 0013, FIG. 4). .
However, in this technique, a plurality of air diffusers are provided, and a control device is attached to each of the air diffusers, and each air diffuser is controlled individually by the control device to diffuse air. Yes. For this reason, it is expensive as an aeration apparatus.

  In addition, an air diffuser is provided at the bottom of the tank, and the entire surface is aerated by aeration from the entire air diffuser of the air diffuser. There is also a technique that prevents the stagnation (Patent Document 2, paragraphs 0009 to 0010).

  This invention makes it a subject to diffuse (stir) the sludge deposit of a tank bottom part by an inexpensive means in a whole surface aeration type.

In order to achieve the above-mentioned problem, the present invention adopts the stirring action by the swirling flow of the above-mentioned Patent Document 2 and generates a swirling flow by diffusing from a part of the diffusing tube that performs aeration on the entire surface. The sediment sludge at the bottom of the tank was diffused.
In this way, if the swirl flow is generated by aeration from a part of the diffuser tube that performs aeration of the entire surface, the swirl flow is separated from the aeration device for the entire surface aeration as in the technique described in Patent Document 1. Compared to the case where an air diffuser is provided to cause the problem, the cost is low.

Next, according to the present invention, for example, a riser pipe branched from the air supply pipe for aeration is used to switch between the generation of the entire aeration and the swirling flow by switching the valve. The air supply is performed, and the switching is performed by a valve provided between the air supply pipe and both branch riser pipes.
In this way, if the air supply during the entire aeration and the air supply during the swirling flow are performed by one air supply pipe and the switching is performed by a valve, the structure can be simplified and the cost can be reduced. .

  Since the present invention is configured as described above, it is possible to perform aeration with high efficiency by aeration over the entire surface while reducing the cost and eliminating the accumulation of sludge at the bottom of the tank.

  The operation method of the aeration tank according to the present invention that achieves the above object can be employed in an aeration tank in an sewage treatment plant, an aeration tank for an activated sludge method, an aeration tank for livestock manure storage tanks, etc. In the method of aeration by aeration from the inside of the aeration device, normally, the entire aeration is performed by sending air to all the aeration tubes of the aeration device, and when sludge is accumulated at the bottom of the aeration tank, It is possible to adopt a configuration in which the sludge accumulated in the bottom of the aeration tank is agitated by sending air to only a part of the air diffuser of the air diffuser.

At this time, if a vertical partition wall is provided between some of the diffuser pipes and the other diffuser pipes, the inside of the tank is divided into an upflow area and a downflow area by the partition walls. Since the swirl flow is easily generated, the stirring action is also smoothed.
In addition, the other air diffuser can be raised and lowered on one side thereof, and when the swirl flow is generated, if the other air diffuser is raised, the other air diffuser can serve as the partition wall. At the same time, the swirl flow is smoothly generated without disturbing the swirl flow.

  As an embodiment of the present invention relating to an aeration tank that achieves the above-mentioned problems, an air diffuser is provided in the aeration tank, and air can be selectively supplied to all or only some of the air diffusers of the air diffuser. Ordinarily, the entire surface is aerated by sending air to all the diffuser pipes of the diffuser, and if sludge accumulates at the bottom of the aeration tank, only a part of the diffuser pipes of the diffuser It is possible to employ a configuration in which the sludge accumulated in the bottom of the aeration tank is stirred by generating a swirling flow by feeding air.

  As an air supply structure to the diffuser in this configuration, a riser pipe branched from the air supply pipe is provided in the above-mentioned part of the diffuser pipes and other diffuser pipes, and air is supplied to both diffuser pipes by the riser pipes. It is possible to employ a configuration in which air can be supplied and air can be selectively supplied only to both the diffuser pipes or only a part of the diffuser pipes by a valve provided between the air supply pipe and both branch riser pipes.

  In these configurations, the other air diffuser can be raised and lowered on one side thereof, and when the swirl flow is formed, the other air diffuser can be erected. Since the diffusing pipe is standing, it does not interfere with the swirling flow, and the flow is made smooth, and the other diffusing pipe that stands up performs the action of the partition wall.

In this configuration where the other diffusing pipes can be raised and lowered, the above-mentioned part of the diffusing pipes and other diffusing pipes are provided with riser pipes branched from the air supply pipes, and air is supplied to both of the diffusing pipes by the riser pipes In addition, a universal pipe joint is interposed in a riser pipe that reaches another diffuser pipe so that the other diffuser pipe can be raised and lowered, and the universal pipe joint can have an on-off valve function.
In addition, it is possible to supply air continuously from some diffuser pipes to other diffuser pipes by the riser pipes and lateral pipes from the above air supply pipes, and a universal pipe joint is provided in the lateral pipes at the boundary between both diffuser pipes. In addition, the universal pipe joint may have an on-off valve function.
With these configurations, when the above-mentioned swirling flow is generated, when the other air diffuser is raised via the universal pipe joint, the air supply to the other air diffuser is cut off by the opening / closing valve function. can do.

  As means for raising and lowering the other diffuser pipe, an air bag is provided on the other side of the diffuser pipe by a wire led from the diffuser pipe to the upper surface of the aeration tank, and air is supplied to the airbag. For example, it is possible to employ inflating and performing the buoyancy of the airbag. At this time, it is possible to provide a weight for returning to the fallen state on the other side of the other air diffusing tubes so that the entire surface can be smoothly returned to the state during aeration.

  These aeration tanks can perform smooth aeration by the above operation method, and similarly, a partition wall in the vertical direction is provided between a part of the air diffuser and another air diffuser, and stirring is performed. The action can be made smooth.

  One embodiment is shown in FIGS. 1 and 2, and in this embodiment, the diffuser 10 is provided in a horizontal state along the bottom surface length direction of the aeration tank 1 having a rectangular shape in plan view. Each air diffuser 10 is divided into two air diffusers 10a and 10b at substantially the center, and each air diffuser is on the same surface provided with the ultrafine bubble diffuser 12 on both sides of the lateral tube 11. Each of them is supported on the bottom of the tank 1 by a support base 13 with a gap of about 50 cm.

A riser pipe 15 branched from one air supply pipe 14 is connected to the lateral pipe 11 of each of the air diffusers 10a and 10b, and air is supplied from the air supply pipe 14 to each lateral pipe 11 via the riser pipe 15. Is supplied, and ultrafine bubbles are discharged from each diffuser tube 12 and diffused over the entire area of the tank 1, and the inside of the tank 1 is aerated by the diffused air.
Each riser pipe 15 is provided with an open / close valve 16, and air is selectively supplied to the air diffusers 10 a and 10 b by opening and closing the open / close valve 16.

This embodiment has the above-described configuration. Normally, each on-off valve 16 is opened and air is supplied to all the air diffusers 10a and 10b (all air diffusers 10) to diffuse the entire area in the tank 1. Aeration.
When sludge is accumulated at the bottom of the tank 1, the open / close valve 16 of the riser pipe 15 connected to one of the air diffusers (air diffuser pipes) 10a or 10b of each air diffuser 10 is closed, and the other air diffuser 10b or By sending air only to the diffuser pipe 12 of 10a, the sludge accumulated in the bottom part of the aeration tank 1 by a swirling flow is stirred.

  The sludge agitation by the swirl flow is performed by operating the on-off valve 16 or automatically operating the on-off valve 16 every predetermined time each time the sludge accumulation is visually confirmed. The fixed time is set appropriately based on experiments and actual operations. Moreover, the amount of sludge accumulation can be detected by a sensor, and the operation can be performed based on the detection signal. The operation time of the swirling flow is also set appropriately according to the amount of accumulation based on the experiment and actual operation.

In the embodiment shown in FIG. 3 and FIG. 4, one air diffuser 10 b of each air diffuser 10 (“other air diffuser” referred to in “Claims”) can be raised and lowered on one side. There is a single riser pipe 15 and lateral pipe 11 from the air supply pipe 14 to the other air diffuser 10a ("part of air diffuser" in the "claims") to one air diffuser 10b. Air can be supplied continuously.
It is assumed that a universal pipe joint 17 such as a swivel joint is interposed in the lateral pipe 11 at the boundary between the diffusers 10a and 10b, and the universal pipe joint 17 has an on-off valve function.

In the embodiment of FIG. 3, a wire 18 and a weight 19 are provided on one side edge of one air diffuser 10 b, and the wire 18 is led to the upper surface of the aeration tank 1, and by pulling the wire 18, As shown by the chain line in the figure, one air diffuser 10b stands up.
If the wire 18 is loosened, the one air diffuser 10b falls down due to the weight 19 and its own weight and returns to the horizontal state (solid line state).

In the embodiment of FIG. 4, an air bag 20 is provided on the other side of one air diffuser 10 b, an air supply hose 21 is connected to the air bag 20, and a valve 22 interposed in the hose 21 is appropriately set. When air is supplied to the airbag 20 via the hose 21 and expanded by opening and closing, the one air diffuser 10b stands up due to the buoyancy of the airbag 20 as shown by the chain line in the figure.
On the other hand, if the air in the airbag 20 is removed through the hose 21 by appropriately opening and closing the valve 22, the one air diffuser 10b falls down due to the weight 19 and its own weight and returns to the horizontal state (solid line state).

In both of these embodiments, normally, as shown in the solid lines in the figure, all the air diffusers 10a and 10b (all air diffusers 10) are placed with the air diffusers 10a and 10b of each air diffuser 10 in a horizontal state. Air is supplied and diffused over the entire area of the tank 1 to perform aeration on the entire surface.
When sludge is accumulated at the bottom of the tank 1, one air diffuser 10b is erected as shown by a chain line, and the air flow to the air diffuser 10b is blocked by the open / close valve function of the universal pipe joint 17 by the erection. Thereby, air will be sent only into the other aeration part 10a, and a swirl flow will arise and the sludge accumulated in the bottom part of the aeration tank 1 will be stirred.
This air supply may be continued during the standing action of the air diffuser 10b. However, the air supply may be temporarily stopped and the air supplied after the air diffuser 10b is raised.

When the swirl flow eliminates sludge accumulation at the bottom of the aeration tank 1 (if it diffuses), one of the air diffusers 10b is laid down and returned to the horizontal state, and the entire surface is aerated.
The sludge agitation by the swirl flow is performed by standing up one of the air diffusers 10b every time the sludge accumulation is confirmed by visual observation, or by automatically operating the standing up at regular intervals. The fixed time is appropriately set based on experiments and actual operations. Moreover, the amount of sludge accumulation can be detected by a sensor, and the operation can be performed based on the detection signal. The operation time of the swirling flow is also set appropriately according to the amount of accumulation based on the experiment and actual operation.

  In each of the above embodiments, the partition wall 30 in the vertical direction is provided between the one air diffuser 10b and the other air diffuser 10a of the air diffuser 10 as shown by the chain line in FIG. Can be provided. If it does in this way, the inside of the tank 1 can be divided into an upflow area and a downflow area by the partition wall 30, it becomes easy to produce the said turning flow, and the said stirring action also becomes smooth. The partition wall 30 may be only upward or downward.

In each of the above embodiments, since air is supplied to each diffuser 10 by one air supply pipe 14, the equipment is also cheaper, and the control thereof, for example, air supply during full aeration and swirl flow It is easy to change the amount appropriately.
Further, since the accumulated sludge at the bottom of the tank 1 is agitated by the swirling flow, the position of each air diffuser 10 can also be set to a relatively high position from the bottom of the tank 1, and if it becomes higher, the pressure loss is also increased. Since the air supply pressure can be reduced while decreasing, it is advantageous in relation to the supply air capacity. For this reason, even in the deep aeration tank 1 having a water depth of about 8 to 10 m, by adopting the present invention, a smooth aeration action can be obtained. For example, the air diffuser 10 can be installed in the middle of the water depth of the tank 1.

In each embodiment, each of the valves 16 and 22 uses a three-way valve or the like, and performs selective air supply / exhaust to both the air diffusers 10a and 10b by using one valve. You can also.
Also in the embodiment of FIGS. 1 to 2, the universal pipe joint 17 is interposed in the middle of the riser pipe 15 parallel to the bottom of the tank 1, and the air diffuser 10 b is raised by standing the other air diffuser 10 b. It is also possible to cut off the air supply to the.

  Incidentally, in each of the above embodiments, when the aeration action by the swirl flow is performed, the stirring action of the accumulated sludge at the bottom of the tank, for example, in one embodiment of FIG. (Aeration tube) The on-off valve 16 of the riser pipe 15 connected to the air diffuser 10a or 10b is closed, and air is sent only to the other air diffuser 10b or 10a to generate a swirling flow. The aeration by the swirling flow can be employed when suppressing nitrification in winter, but is not limited to the winter and is optional and can be appropriately switched to full-surface aeration.

  Further, when the swirl flow is generated, the valves 16 and the like are appropriately opened and closed, and the air supply to the one air diffuser 10b and the other air diffuser 10a of the air diffuser 10 is alternately repeated, and the direction of the swirl flow The clogging of the air diffuser 12 can be eliminated and prevented by the air blowing effect by repeating the above change and the air diffused from the air diffuser 12 and the stop thereof.

  The above example was the case of an aeration tank in a sewage treatment plant, but an aeration tank in which high-concentration manure was introduced and the manure was treated by the activated sludge method, and the hydrogen sulfide odor decreased by aeration. Of course, the present invention can be applied to an aeration tank for a livestock excrement storage tank that has only an ammonia odor, and in this case, each aspect of the above embodiment can be used.

1 shows an embodiment, (a) is a plan view of the embodiment, (b) is a right side view of the same cut, (c) is a right side view of the main cutting section of (b). Schematic perspective view of the embodiment Schematic cut side view of another embodiment Schematic cut side view of another embodiment

Explanation of symbols

1 Aeration tank 10 Air diffuser 10a The other air diffuser (part of the air diffuser)
10b One air diffuser (other air diffuser)
11 Lateral pipe 12 Air diffuser pipe 14 Air supply pipe 15 Riser pipe 16, 22 Open / close valve 17 Universal pipe joint 18 Wire 19 Weight 20 Air bag 21 Air supply hose 30 Partition wall

Claims (14)

A method of providing an aeration device 10 in an aeration tank 1 in a sewage treatment plant, and aeration by aeration from the aeration device 10,
Usually, when aeration is performed on the entire surface by sending air to all of the air diffusers 12 of the air diffuser 10, and sludge accumulates on the bottom of the air tank 1, a part of the air diffuser 10 of the air diffuser 10 is used. 12. A method of operating an aeration tank, characterized in that a swirl flow is generated by feeding air only to 12 and the sludge accumulated at the bottom of the aeration tank 1 is agitated. A method in which an aeration device 10 is provided in the activated sludge method aeration tank 1, and aeration is performed by the aeration from the aeration device 10.
In general, when aeration is performed on the entire surface by sending air to all of the air diffusers 12 of the air diffuser 10, and sludge accumulates on the bottom of the aeration tank 1, a part of the air diffuser 10 of the air diffuser 10 is used. 12. A method of operating an aeration tank, characterized in that a swirl flow is generated by feeding air only to 12 and the sludge accumulated at the bottom of the aeration tank 1 is agitated. The aeration apparatus 10 is provided in the aeration tank 1 for aeration of the livestock manure storage tank to reduce the hydrogen sulfide odor, and the aeration is performed by the aeration from the aeration apparatus 10.
Usually, when aeration is performed on the entire surface by sending air to all of the air diffusers 12 of the air diffuser 10, and sludge accumulates on the bottom of the air tank 1, a part of the air diffuser 10 of the air diffuser 10 is used. 12. A method of operating an aeration tank, characterized in that a swirl flow is generated by feeding air only to 12 and the sludge accumulated at the bottom of the aeration tank 1 is agitated.   4. A vertical partition wall 30 is provided between a part of the air diffuser and another air diffuser to facilitate the swirling flow. How to operate the aeration tank.   4. The air diffuser according to claim 1, wherein the other air diffuser can be raised and lowered on one side thereof, and when the swirl flow is generated, the other air diffuser is erected. How to operate the aeration tank. An aeration apparatus for performing the operation method of the aeration tank according to claim 1,
The air diffuser 10 is provided in the aeration tank 1 so that air can be selectively supplied to all or only a part of the air diffuser of the air diffuser. When the entire surface is aerated by sending air into the aeration tube, and sludge accumulates in the aeration tank 1, a swirl flow is generated by sending air only to some of the aeration tubes of the aeration device 10. The aeration apparatus characterized by stirring the sludge accumulated in the aeration tank 1.   A riser pipe 15 branched from the air supply pipe 14 is provided in the part of the diffuser pipes and the other diffuser pipes so that air can be supplied to both of the diffuser pipes by the riser pipe 15. The aeration apparatus according to claim 6, wherein air can be selectively supplied to both of the diffuser pipes or only a part of the diffuser pipes by a valve 16 provided between the first and second branch riser pipes 15.   The aeration apparatus according to claim 6 or 7, wherein other aeration tubes other than the part of the aeration tubes are allowed to be raised and lowered, and the other aeration tubes are erected when the swirling flow is generated.   A riser pipe 15 branched from the air supply pipe 14 is provided in the part of the diffuser pipes and the other diffuser pipes so that air can be supplied to both of the diffuser pipes by the riser pipe 15 and the other diffuser pipes. A riser pipe 15 is provided with a universal pipe joint 17 so that other diffuser pipes can be raised and lowered. The universal pipe joint 17 has an on-off valve function, and when the above-mentioned swirl flow is generated, the other The aeration apparatus according to claim 6, wherein the air diffusion pipe is erected through the universal pipe joint 17 and the air supply to the other air diffusion pipes is shut off by the open / close valve function.   The riser pipe 15 and the lateral pipe 11 from the air supply pipe 14 can continuously supply air from a part of the diffuser pipes 10a to the other diffuser pipes 10b, and the lateral pipe 11 at the boundary between the diffuser pipes 10a and 10b. The other diffuser pipe 10b can be raised and lowered with a universal pipe joint 17 interposed therebetween, and the universal pipe joint 17 has an open / close valve function. When the swirl flow is generated, the other diffuser pipe 10b is provided. The aeration apparatus according to claim 6, wherein the aeration apparatus is erected through the universal pipe joint 17, and the air supply to the other air diffuser pipe 10 b is shut off by the open / close valve function.   The aeration apparatus according to any one of claims 8 to 10, wherein the other aeration pipe 10b is erected by a wire 18 led from the aeration pipe 10b to the upper surface of the aeration tank 1.   An air bag 20 is provided on the other side of the other air diffuser 10b, and the air diffuser 10b is inflated by supplying air to the air bag 20, and the other air diffuser 10b is erected by the buoyancy of the air bag 20. The aeration apparatus according to any one of claims 8 to 10, wherein   The aeration apparatus according to any one of claims 8 to 12, wherein a weight 19 for returning to a lying state is provided on the other side of the other diffuser tube 10b.   The aeration apparatus according to any one of claims 6 to 13, wherein a partition wall 30 in the vertical direction is provided between a part of the air diffuser and another air diffuser.

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