JP2562397B2 - Batch processing tank scum and supernatant discharge device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scum for a batch type processing tank and a scum for a batch type processing tank, wherein scum floating on the liquid surface in the batch type processing tank and discharge of the supernatant can be selectively performed. The present invention relates to a clear liquid discharge device.

[0002]

2. Description of the Related Art It is already known to equip a treatment tank for carrying out batch type activated sludge treatment of inflowing sewage with a supernatant liquid discharging device or a scum discharging device. However, none of the latter scum discharging devices has a practically satisfactory type.
In particular, most conventional scum discharging devices are of a type that scrapes off and eliminates floating scum on the liquid surface only at a constant water level in the processing tank.

[0003]

However, if the processing tank is equipped with the supernatant discharge device and the scum discharge device as described above, the following problems occur. B) If both the supernatant liquid discharging device and the scum discharging device are provided in the treatment tank, not only will the cost increase, but in the case of the scraping type scum discharging device, the floating scum can be removed only at a certain water level in the treatment tank. Since it cannot be scraped and collected, an effective scum scraping function cannot actually be obtained in a batch type activated sludge treatment tank in which the water level changes frequently. B) Therefore, it is possible to use a scum discharge device with a structure that can cope with frequent fluctuations in the water level in the tank.
As a result, the structure of the scum discharging device becomes very complicated, resulting in further cost increase. Due to the reasons (1) and (2) above, the actual means for removing scum is to make the scum flow out together with the overflow water from the treatment tank due to heavy rainfall (heavy rain), or The actual situation is that the floating scum is collected and eliminated by an artificial operation when the water level is reached. However, in the case of the former method of scum elimination by the overflow method due to heavy rainfall, heavy rain rarely falls, and scum cannot be eliminated without a large amount of rainfall, and in the latter scum elimination method by artificial work, considerable labor is required. In addition to the above, there is a problem that the floating scum in the central part of the tank cannot be eliminated and there is a risk.

The present invention has been made in order to solve the above problems and does not require any artificial removal work of floating scum diffused on the liquid surface in the processing tank, and
To efficiently, smoothly, and reliably exhibit the scum discharge function and the supernatant discharge function according to the fluctuation of the water level in the tank with a movable overflow weir that can move up and down along the outlet of the processing tank. It is an object of the present invention to provide a scum for a batch type processing tank and a supernatant liquid discharging device capable of significantly reducing the equipment cost and the running cost.

[0005]

A scum for a batch type treatment tank and a supernatant discharge device according to the present invention include a scum floating on the liquid surface of a treatment tank for receiving inflowing wastewater and performing batch type activated sludge treatment. An outlet part for letting out the supernatant liquid,
A movable overflow weir arranged so as to be able to move up and down along the outlet portion, a weir raising and lowering drive means for raising and lowering the movable overflow weir, an outflow water channel communicating with the outflow port portion, and a downstream of the outflow water channel. A bifurcated drainage channel formed on one side, and one of the bifurcated drainage channels is opened and the other drainage channel is closed, or vice versa, one drainage channel is closed and the other drainage channel is opened. In the treatment tank, there is provided a water channel switching means for switching to the treatment tank, and a wind inflow means for injecting wind from the outside into the treatment tank and directing the wind toward the movable overflow weir side along the liquid level in the tank. is there.

[0006]

In the scum and the supernatant liquid discharging device of the batch type processing tank according to the present invention, the height of the movable overflow weir is adjusted according to the fluctuation of the liquid level in the tank by elevating the movable overflow weir of the processing tank. The height is adjusted so that the floating scum and the supernatant liquid on the liquid level in the tank are selectively discharged by adjusting the height. That is, when scum is discharged from the treatment tank, first, the water channel switching means switches the forked drainage channel on the downstream side of the outflow water channel so that one drainage channel is opened and the other drainage channel is closed. During the precipitation step in this state, the wind inflow means draws in external air toward the movable overflow weir into the processing tank, and the incoming air diffuses the liquid over the liquid surface in the processing tank. The floating scum flows and moves toward the movable overflow weir, and accumulates in the vicinity of the movable overflow weir. When the floating scum on the liquid level in the tank accumulates near the movable overflow weir in this way, the movable overflow weir is lowered to the position where the top of the weir is slightly submerged so that the floating overflow near the movable overflow weir. The accumulated floating scum is discharged from the outlet of the processing tank to the outflow channel. Then, the scum released to the outflow water channel is discharged to the outside of the system from the drainage channel opened by the water channel switching means as described above.
Therefore, in this case, the one drainage channel serves as a scum-only drainage channel and the other drainage channel serves as a supernatant-only drainage channel. When the removal of the floating scum is completed in this way, the supernatant liquid is then discharged (discharge step). At this time, one of the bifurcated drainage channels is closed and the other drainage channel is opened. As a result, the supernatant liquid discharged from the outlet of the processing tank to the outflow water channel is discharged from the other discharge path that is a supernatant liquid exclusive discharge path on the downstream side of the outflow water channel. As described above, even with one movable overflow weir, the floating scum on the liquid level in the tank and the supernatant can be discharged smoothly with a time lag.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a cross-sectional plan view of a batch-type processing tank according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the same, and FIG. 3 is a sectional view taken along line AA of FIG. In these figures, 1 is a single treatment tank for performing batch activated sludge treatment (repeating of aeration process, sedimentation process and discharge process), 2 is this treatment tank 1
Is provided in the front wall of the processing tank 1, 3 is provided in the rear wall of the processing tank 1, and the floating scum S on the liquid surface in the tank and the outlet for discharging the supernatant liquid are 4 It is an outflow water channel which is formed integrally with the processing tank 1 and communicates with the outflow port section 3. Downstream of this outflow water channel 4, the forked drainage channels 4A and 4B are provided.
Are branched. These forked drainage channels 4A, 4B
, One of the drainage channels 4A is a scum-only drainage channel,
The other drainage channel 4B serves as a discharge channel dedicated to the supernatant. An opening / closing lid 5 is attached to the upper opening of the processing tank 1 as shown in FIG. This open / close lid 5
As a wind inflow means for introducing a summer seasonal wind into the treatment tank 1 to blow up and accumulate the floating scum S on the liquid level in the tank toward the outflow port 3 side (the movable overflow weir 6 side described later). Function.

In the processing tank 1, the outlet 3
A movable overflow weir 6 that can be moved up and down along the outlet 3 is disposed inside the. The movable overflow weir 6 has height adjustment and floating scum S according to the water level fluctuation in the processing tank 1.
In order to adjust the height at the time of discharging, the weir opening / closing device (weir raising / lowering driving means) 7 is driven to move up and down.

Further, a blower 9 is provided on the upper part of the movable overflow weir 6 via a support frame 8, and the blower 9 is operated with the opening / closing lid 5 closed in winter. As a result, the external air is sucked into the processing tank 1 from the ventilation port 2, and the floating scum S on the liquid level in the tank functions as a wind inflow means for directionally collecting the floating scum S toward the movable overflow weir 6.

[0010] Here, generally, the summer monsoon is a wind from the south, and scum in the treatment tank 1 for performing batch type activated sludge treatment is large in summer and small in winter. Therefore, the treatment tank 1 is installed in a direction in which the seasonal wind of summer can be efficiently introduced toward the movable overflow weir 6 side by opening the opening / closing lid 5 in summer.

Each of the bifurcated drainage channels 4A, 4B is provided with a gate (water channel switching means) 10A, 10B for individually opening and closing the drainage channels 4A, 4B. In these gates 10A and 10B, one gate 10A is one drainage channel 4A of the forked drainage channels 4A and 4B.
When the gate is opened, the other gate 10B closes the other drainage channel 4B, and conversely, one gate 10A closes the other drainage channel 4A.
When the gate is closed, the other gate 10B is opened and closed by the gate switches 11A and 11B (only one switch 11A is shown in FIG. 3) so as to open the other drainage channel 4B.

An overflow pipe 12 (see FIG. 3) which opens at the water level upper limit position of the water passage communicates with the outflow water passage 4. In addition, reference numeral 1A in FIG. 1 denotes a concentrating tank portion partitioned and formed in the processing tank 1.

Next, the operation will be described. The treatment tank 1 repeats the aeration process, the precipitation process, and the discharge process while receiving the sewage. In the precipitation process, the movable overflow weir 6 is set at the height of the liquid surface by observing when the sludge interface is sufficiently settled. And the gate 10A of the scum discharge system of the bifurcated drainage channels 4A and 4B is opened, and the gate 10B of the supernatant discharge system is closed. In this state, in summer, when the opening / closing lid 5 is opened, the air flows from the outside into the space above the liquid surface in the processing tank 1. Since this wind flows from the facing surface side of the movable overflow weir 6 toward the movable overflow weir 6, the wind scatters the floating scum S on the liquid level in the tank toward the movable overflow weir 6. . As a result, the floating scum S accumulates near the movable overflow weir 6.

The above is the case in the summer, but in the winter, when the opening / closing lid 5 is closed and the blower 9 is operated, the treatment tank 1 is operated.
The outside air is sucked from the vent portion 2 provided in the wall portion facing the suction side of the blower 9 in, and the sucked air flows to the movable overflow weir 6 side along the liquid level in the tank. As a result, the floating scum S that has diffused to the liquid level in the tank flows and moves toward the movable overflow weir 6, and accumulates in the vicinity of the movable overflow weir 6.

In this way, by using the seasonal wind in the summer and operating the blower 9 in the winter, the floating scum S diffused on the liquid surface in the processing tank 1 can be moved. When the floating scum S accumulates in the vicinity of the movable overflow weir 6, it is possible to make a flow transition toward the overflow overflow weir 6, and when the floating scum S accumulates near the movable overflow weir 6, the weir top of the movable overflow weir 6 is slightly reduced. The movable overflow weir 6 is lowered so as to be submerged in water. Then, the floating scum S accumulated as described above flows out from the outflow port portion 3 into the outflow water channel 4, and then the outflow scum S is discharged to the outside of the system through one drainage channel 4A of the forked drainage channels 4A and 4B. It The blower 9 may be operated in the summer, and in this case, the inflow of the seasonal air may be used together to minimize the operating time of the blower 9 and enhance the efficiency of collecting the floating scum S. it can.

When the removal of the floating scum is completed in this way, the supernatant liquid is then discharged (discharge step). At this time, the gate 10A of the scum discharge system is closed and the gate 10B of the supernatant discharge system is opened, and the movable overflow weir 6 is lowered so that the weir top is submerged near the in-layer liquid surface, The supernatant liquid is discharged from the outlet portion 3 of the treatment tank 1 into the outflow water channel 4, and the supernatant liquid is then discharged from the forked drainage channels 4A and 4B.
On the other hand, it is discharged to a predetermined supernatant liquid recovery destination through the drainage channel 4B.

In the above embodiments, the forked drainage channels 4A and 4B are used.
Switching of two gates 10A, 1 of each system
Since it was done individually at 0B, by any chance the movable overflow weir 6
If there is any failure or operation mistake in the
When A and 10B are closed, the sludge in the treatment tank 1 will not be discharged to the outside. However, it goes without saying that the switching of the bifurcated drainage channels 4A and 4B may be performed by one gate valve. Further, it may be an ascending / descending driving means for the movable overflow weir 6, or may be an artificial or automatic means.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the upper end of the rotating submerged weir 60 is freely rotatable up and down via the pin P above the movable overflow weir 6. The rotating submerged weir 60 is suspended in water along the movable overflow weir 6 with a weight 61. In the case of this embodiment, when the scum is discharged in the precipitation step, the rotating submerged weir 60 is pulled up above the liquid level in the tank, so that the same scum discharge as in the case of the previous embodiment can be smoothly performed. it can. Further, when the supernatant liquid is discharged, the rotating submerged weir 60 is suspended in the water along the movable overflow weir 6, so that the floating scum still remaining on the liquid surface in the tank at the time of discharging the supernatant liquid. The floating scum S can be blocked so that S does not drain with the supernatant. In addition,
The operation of pulling up and down the rotating submerged weir 60 may be performed by either manual work or automatic driving means. In FIG. 4, reference numeral 62 is a packing attached to the end of the rotary submergence weir 60 on the movable overflow weir 6 side.

[0018]

As described above, according to the present invention, the height of the movable overflow weir is increased by moving the movable overflow weir up and down along the outlet of the treatment tank for performing batch activated sludge treatment. Can be adjusted to a height according to the fluctuation of the liquid level in the tank, and by adjusting the height, the floating scum on the liquid level in the tank and the discharge of the supernatant liquid can be selectively performed with a time lag. . That is, when discharging the scum from the treatment tank, first, the water channel switching means switches the forked drainage channel on the downstream side of the outflow water channel so that one drainage channel is opened and the other drainage channel is closed, and in this state. During the settling step, the wind inflow means draws in external air toward the movable overflow weir into the treatment tank, so that the incoming wind diffuses and floats on the liquid surface in the processing tank. The scum can be flow-transferred toward the movable overflow weir, and efficiently accumulated in the vicinity of the movable overflow weir. When the floating scum on the liquid level in the tank accumulates near the movable overflow weir in this way, the movable overflow weir is lowered to the position where the top of the weir is slightly submerged so that the floating overflow near the movable overflow weir. The accumulated floating scum can be discharged from the outlet of the treatment tank to the outflow water channel, and the discharged scum can be discharged out of the system only from one drainage channel of the scum discharge system opened by the water channel switching means as described above. Can be discharged. After the elimination of such floating scum, the supernatant liquid is discharged (a discharge step). At this time, by closing one drainage channel of the bifurcated drainage channel and opening the other drainage channel, The supernatant liquid discharged from the outlet of the treatment tank to the outflow water channel can be discharged from the other discharge channel that is a supernatant liquid-dedicated discharge channel on the downstream side of the outflow water channel. Therefore, according to the present invention, the scum discharge and the supernatant liquid discharge according to the fluctuation of the water level in the tank can be efficiently and smoothly performed with a time lag only by the movable overflow weir that can be moved up and down along the outlet of the processing tank. Therefore, it is not necessary to provide a scum discharging device separate from the supernatant discharging device, and the facility cost can be significantly reduced. Also, as the wind inflow means in the treatment tank at the time of scum discharge, it is possible to use natural wind, so the running cost can be reduced, and furthermore, the floating scum on the liquid level in the tank can be blown off by wind force. It is also possible to reduce the discharge amount of the supernatant liquid discharged together with the scum.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of a batch type processing tank according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a sectional configuration explanatory diagram of a main part according to another embodiment of the present invention.

[Explanation of symbols]

 1 Treatment Tank 3 Outlet Port 4 Outflow Channel 4A One-way Drain Channel 4B Another Drain Channel of Two-way Drain Channel 5 Air Inflow Means 6 Movable Overflow Weir 7 Weir Elevating Drive Means 9 Blower (Air Inflow Means) 10A Gate (Waterway switching means) 10B Gate (waterway switching means)

Claims (1)

(57) [Claims] 1. A scum and a supernatant discharge device of a treatment tank which receives inflowing wastewater and performs batch type activated sludge treatment,
The treatment tank comprises an outlet part capable of flowing out the floating scum and the supernatant liquid on the liquid level in the tank, a movable overflow weir arranged so as to be vertically movable along the outlet part, and the movable overflow weir. A weir elevating drive means for moving up and down, an outflow water channel communicating with the outflow port, a bifurcated drainage channel branched on the downstream side of the outflow water channel, and a bifurcated drainage channel of which one drainage channel is open and On the other hand, the drainage channel is closed, or conversely, the one drainage channel is closed so that the other drainage channel is opened, and a channel switching means for allowing the wind to flow into the treatment vessel from the outside and the wind in the vessel. A scum and a supernatant liquid discharging device for a batch type processing tank, comprising: an air inflow means directed toward the movable overflow weir side along a liquid surface.