JPH0131957B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides an underwater stirring device that can be used for both aerobic treatment using stirring aeration and anaerobic treatment using low-speed stirring in sewage treatment facilities, with the performance switched. It is related to.

(Prior Art) In recent years, a batch activated sludge treatment method has been attracting attention as one of the small-scale sewage treatment methods. This processing method includes the following four steps as one cycle.

In aerobic treatment using high-speed stirring aeration
BOD removal, nitrification treatment and excessive phosphorus incorporation into activated sludge.

Denitrification process in anaerobic treatment using low-speed stirring.

Sedimentation process of activated mud by standing still.

Discharge of supernatant water and extraction of excess sludge.

By the way, mechanical type and aeration type have been conventionally used as stirring aeration devices for performing the above-mentioned aerobic treatment. Mechanical devices include those that rotate a stirring blade near the water surface to draw in air to create a water flow, or an ejector that connects an air pipe to the pump's discharge injection hole to mix air into the jet of the pump. There are some that cause water flow while doing so. An air diffuser type device is one in which a bubble generator such as an air diffuser pipe or plate is installed at the bottom of the aquarium and communicates with an air source, and a large amount of air is supplied from the air source to cause water flow as the air bubbles rise. etc.

Although these stirring aeration devices are suitable for performing aerobic treatment, they are not suitable for performing anaerobic treatment using only low-speed stirring by cutting off contact with air as much as possible. For this reason, a low-speed stirring device for anaerobic treatment is provided separately from the stirring and aeration device for performing aerobic treatment.

(Problems to be Solved by the Invention) As mentioned above, in the batch activated sludge treatment method, the conventional stirring aeration equipment is unsuitable for the anaerobic treatment process, and a separate There was a problem in that a low-speed stirring device was required, which made the equipment that much more expensive. In addition, conventional stirring aeration devices using mechanical stirring blades have problems in that the moving parts generate noise above the water surface and it is difficult to aerate the bottom of the sewage tank. In addition, the discharge jet of a mechanical pump has the disadvantage that the discharge flow rate is extremely high and strong turbulence occurs, resulting in large energy loss and easy destruction of microbial flocs. Furthermore, the aeration type requires a bubble generator over a wide area at the bottom of the tank to achieve sufficient agitation, requires a large amount of air, and the equipment including the air source is expensive.
There is a problem in that the aeration holes tend to become clogged due to sedimentation of sludge when stirring aeration is stopped.

The object of the present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an underwater stirring device that can be used for both stirring aeration and low-speed stirring by switching its performance.

(Means for Solving the Problems) In order to achieve the above object, the underwater agitation device of the present invention has a vertical shaft axial flow pump that is housed in an outer casing, and on the discharge side of the vertical shaft axial flow pump, a A truncated cone-shaped discharge cone forming a flow path is provided, and a circumferential discharge port is formed between the discharge cone and the end of the outer casing, and the opening/closing and opening degree of the discharge port is controlled. An annular slide gate slidable in the axial direction is provided in the outer body casing so as to be adjustable, and an air diffuser hole is provided in the discharge cone facing the flow path, and an opening/closing valve is interposed in the air diffuser hole. Communicating with an air source through a pipe, increasing the opening of the discharge port and opening the on-off valve to perform aerobic treatment by stirring aeration, reducing the opening of the discharge port and closing the on-off valve. The structure is such that anaerobic treatment can be performed using low-speed stirring.

(Function) A truncated cone-shaped discharge cone is provided on the discharge side of the vertical shaft axial flow pump, the flow path is widened at the end and radial in the axial direction, and the circumferential discharge opening of this flow path is connected with a slide gate. Since opening/closing and the opening degree can be adjusted, by adjusting the opening degree of the slide gate, the fluid resistance of the discharge port can be adjusted and the discharge flow rate can be adjusted. Then, by adjusting the discharge flow rate, the discharge flow rate is increased or decreased, and the amount of intake air taken in from the air diffuser holes provided facing the flow path is increased or decreased. Furthermore, if the on-off valve is closed to shut off the air diffuser hole and the air source, air bubbles will not be mixed into the water from the air diffuser hole. Therefore, by increasing the opening of the discharge port using a slide gate and opening the on-off valve, a large amount of air bubbles are mixed into the large discharge flow rate, and aerobic treatment is performed by stirring aeration, which increases the opening of the discharge port. By setting the flow rate to be small and closing the on-off valve, anaerobic treatment can be performed by low-speed stirring without mixing air bubbles with a small discharge flow rate.

(Example) Hereinafter, Figures 1 to 3 will be described for examples of the present invention.
This will be explained with reference to the figures. FIG. 1 is a sectional view of an embodiment of the underwater stirring device of the present invention, and FIG.
FIG. 3 is an explanatory diagram of an example of a mechanism for adjusting the opening degree of the slide gate shown in FIG. 1, and FIG. 3 is a characteristic diagram of the discharge flow rate by adjusting the opening degree of the slide gate.

In FIG. 1, an axial flow impeller 2 rotationally driven by a submersible motor 1 is installed inside an outer body casing 3 supported by ribs 4, and a vertical shaft axial flow pump 5 is installed.
is configured. The end of the outer body casing 3 on the suction side of the vertical shaft axial flow pump 5 is opened in a bell shape to form a suction port 6. Further, the end of the outer body casing 3 on the discharge side is formed with a truncated cone-shaped discharge cone 7 at intervals which deflects the discharge flow diagonally outward and widens at the end to form a flow path radial with respect to the axial direction. A circumferential discharge port 9 is formed between the discharge cone 7 and the end of the outer casing 3. A mirror plate 10 is provided at the bottom of the discharge cone 7, and a hollow chamber 11 is formed inside the discharge cone 7. From this hollow chamber 11, facing the discharge port 9, a large number of small aeration holes 12, 1 are formed.
2... are arranged and drilled in a circumferential manner. One end of an air pipe 13 opens into the hollow chamber 11 and communicates with an air source (not shown) or the outside air via an on-off valve 22 . Further, an annular slide gate 14 is provided on the outer periphery of the outer casing 3 so as to be slidable in the axial direction.
The opening/closing and opening degree adjustment of the discharge port 9 is performed by this. When the discharge port 9 is closed by the slide gate 14, the slide gate 14 comes into contact with the opening of the air diffuser holes 12, 12...
...is blocked. A plurality of legs 15, 15, .

The mechanism for adjusting the opening degree of the slide gate 14 is the second one.
As shown in the figure, a fulcrum 16 provided on the outer casing 3
An operating arm 17 is swingably provided at the aquarium, and one end of the operating arm 17 is connected to the slide gate 14 via an operating rod 18, and the other end of the operating arm 17 is connected via a driving rod 19 to a pedestal, etc. at the top of the aquarium. It is connected to the installed electric device 20 and manual device 21. The electric device 20 uses a limit switch or the like, and the manual device 21 uses a stopper or the like to appropriately limit the sliding range of the slide gate 14, and within that range, the slide gate 14 can arbitrarily set the opening degree of the discharge port 9. .

In this configuration, if the slide gate 14 opens the discharge port 9 widely, the fluid resistance of the discharge port 9 is small, and a large discharge flow rate is radially outward from the vertical axial flow pump 5, as shown by the solid line in FIG. It can be spewed out and create water currents over a wide area.
Furthermore, if the slide gate 14 opens the discharge port 9 to a small extent, a small discharge flow rate is discharged and the water flow is generated only in a narrow range, as shown by the broken line in FIG. In addition, if the on-off valve 22 is opened and the hollow chamber 11 is in communication with the air source or the outside air, when the flow velocity is high, the ejector effect will increase the air diffusion hole 1.
2, 12...A larger amount of air can be sucked in and a larger amount of bubbles can be drawn into the water, and when the flow rate is slow, a smaller amount of air bubbles can be drawn into the water. moreover,
If the on-off valve 22 is closed to isolate the hollow chamber 11 from the air source or the outside air, air bubbles from the air diffusion holes 12, 12, . . . will not be trapped.

Therefore, by adjusting the slide gate 14 to widen the discharge port 9 and opening the on-off valve 22 to communicate the hollow chamber 11 with the air source or the outside air, a large amount of discharge flow rate containing a large amount of air bubbles is sufficient. Aerobic treatment by stirring and aeration can be performed. Further, by reducing the opening of the discharge port 9 and closing the on-off valve 22, anaerobic treatment can be performed by low-speed stirring with a small discharge flow rate and no air bubbles mixed in. Note that if the discharge port 9 is closed by the slide gate 14, the air diffusion holes 12, 12, .

FIG. 4 is a partial diagram of another embodiment of the underwater stirring device of the present invention. In FIG. 4, an air bubble storage chamber 3 that stores some of the air bubbles drawn into the water from the air diffuser holes 12, 12, etc. is placed in a slide gate 30 that is slidably provided in the outer body casing 3 in the axial direction.
1 is provided, and this bubble storage chamber 31 is provided with an exhaust valve 32. This exhaust valve 32 is configured so that when the slide gate 30 rises to a predetermined height, it comes into contact with a stopper 33 provided on the outer body casing 3 and is opened, so that the air in the bubble storage chamber 31 is discharged. . Furthermore, packing 34 is provided at the portion of the slide gate 30 that comes into contact with the air diffuser holes 12, 12, . . . .

With this configuration, when air accumulates in the bubble storage chamber 31 and the buoyancy becomes strong, the slide gate 30
increases, the discharge flow rate increases, and strong stirring and aeration is performed. Then, when it rises to a predetermined height, the exhaust valve 32 is opened, the air in the bubble storage chamber 31 is exhausted, and the slide gate 30 is lowered.
The discharge flow rate decreases, resulting in weak stirring aeration. In this way, strong and weak stirring aeration is automatically performed alternately at a constant period. In addition, when the slide gate 30 is stopped, the air diffusion holes 12 and 1 are closed by the packing 34.
2... is reliably closed to prevent clogging due to backflow, etc.

FIG. 5 is a partial diagram of still another embodiment of the underwater stirring device of the present invention. In FIG. 5, a packing 35 is provided with one end fixed so as to cover the air diffuser holes 12, 12, . This packing 35 acts as a reed valve, and opens when air is taken in from the air diffuser holes 12, 12, depending on the discharge flow rate, and when stopped, the abutting part of the slide gate 14 opens through this packing 35. A reliable closure is achieved by contacting the

When a plurality of the underwater stirring devices of the present invention described above are installed in a relatively large water tank, as shown in FIG.
1, 41 is converted into linear vertical movement by converters 42, 42..., and the slide gates 14, 30 are adjusted by simultaneously adjusting the drive rods 19 in FIG. 2 of each underwater stirring device. Can be configured. Then, adjustments may be made such as making the stirring aeration of each underwater stirring device stronger on the raw water inflow side and weaker on the downstream side.

In addition, in the above embodiment, the discharge cone 7
Although the air diffuser holes 12, 12... are provided facing the discharge port 9, the invention is not limited to this, and if air bubbles are drawn into the water due to the ejector effect, any position of the discharge cone 7 facing the flow path is provided. Diffusion hole 12,1
2... may be provided. Furthermore, it goes without saying that the underwater stirring device of the present invention can be used not only for the batch activated sludge method but also for stirring and aeration in various water tanks.

(Effects of the Invention) As explained above, according to the underwater agitation device according to the present invention, by increasing the opening degree of the discharge port and opening the on-off valve, a large discharge flow rate containing a large amount of air bubbles can be produced. , aerobic treatment with stirring and aeration can be performed. Furthermore, by reducing the opening degree of the discharge port and closing the on-off valve, anaerobic treatment with low-speed stirring can be performed with a small discharge flow rate that does not introduce air bubbles. Therefore, since the performance of one device can be switched between stirring aeration and low-speed stirring, one device can perform two processes, aerobic treatment and anaerobic treatment, and the equipment is inexpensive. It has the excellent effect of becoming something.

[Brief explanation of drawings]

1 is a sectional view of one embodiment of the underwater stirring device of the present invention, FIG. 2 is an explanatory diagram of an example of the mechanism for adjusting the opening degree of the slide gate in FIG.
The figure is a characteristic diagram of the discharge flow rate by adjusting the opening degree of the slide gate, FIG. 4 is a partial diagram of another embodiment of the underwater stirring device of the present invention, and FIG. FIG. 6 is a partial view of still another embodiment of the stirring device, and FIG. 6 is a diagram showing an example of a mechanism for adjusting the opening degree of the slide gate when a plurality of underwater stirring devices of the present invention are installed in an aquarium. 3: Outer casing, 5: Vertical axial flow pump,
7: Discharge cone, 9: Discharge port, 12: Diffusion hole,
13: Air pipe, 14, 30: Slide gate, 2
2: Open/close valve, 31: Air storage chamber, 32: Exhaust valve, 34, 35: Packing.

Claims (1)

[Claims] 1. A truncated cone-shaped discharge cone forming a flow path radially in the axial direction is provided on the discharge side of a vertical shaft axial flow pump housed in an outer casing. A circumferential discharge port is formed between the cone and the end of the outer casing, and an annular slide is slidable in the axial direction on the outer casing so that the discharge port can be opened/closed and the degree of opening can be adjusted. A gate is provided, an air diffuser hole is provided in the discharge cone facing the flow path, and the air diffuser hole is communicated with an air source through an air pipe with an opening/closing valve interposed therebetween, and the opening degree of the discharge port is increased. The underwater system is characterized in that the opening/closing valve is opened to perform aerobic treatment by stirring and aeration, and the opening degree of the discharge port is reduced and the opening/closing valve is closed to perform anaerobic treatment by low-speed stirring. Stirring device. 2. The underwater stirring device according to claim 1, wherein the discharge cone is provided with aeration holes facing the discharge port. 3. The underwater agitation according to claim 2, wherein when the discharge port is closed by the slide gate, the slide gate contacts and closes the opening of the air diffuser hole. Device. 4. The underwater agitation device according to claim 3, wherein the slide gate is configured to abut against the opening of the air diffusion hole through packing. 5. A bubble storage chamber is provided in the slide gate to collect some of the bubbles from the air diffuser hole, and when the slide gate rises to a predetermined height due to the buoyancy of the bubble storage chamber, the air in the bubble storage chamber is discharged. An underwater stirring device according to any one of claims 1 to 4, characterized in that an exhaust valve is provided.