JPH0768105A - Scum discharging method and device therefor - Google Patents

Abstract

PURPOSE:To discharge the scum on the entire water surface in a single tank in which an org. sewage is treated. CONSTITUTION:A scum discharge device 10 is set in a batch tank 20, and a scum discharge pipe 12 and a supernatant water discharge pipe 14 are connected to the bottom to discharge the scum S and supernatant water in the tank 20. A scum discharge valve 16 to control the discharge of the scum S is provided to the part of the scum discharge pipe 12 projecting outside the tank 20, and two aerating and agitating devices 18 are set at the bottom of the tank 20. The aerating and agitating device 18 is connected to a blower 24 through an air pipe 22 to introduce air into the tank 20 and to aerate and agitate the water. The supernatant water flows out into the discharge pipe 14 through the scum discharge device 10. The upper parts of the scum discharge pipe 12 and supernatant discharge pipe 14 are formed with a bellows pipe and made expansible in accordance with the water level of the tank 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scum discharging device and method thereof, and more particularly to a scum discharging device installed in a batch type activated sludge treatment tank and discharging scum and a method thereof.

[0002]

2. Description of the Related Art As a supernatant water discharge device for discharging supernatant water when a drainage port is submerged, for example, Japanese Utility Model Laid-Open No. 61-91399.
There is one shown in Japanese Patent Publication. In this device, a discharge pipe is arranged in the tank, and the lower end thereof is rotatably supported on a wall surface in the tank. A trough is attached to the upper portion of the discharge pipe, and a lower float is fixed to the lower portion of the trough. Further, an exhaust port is formed in the lower float and communicates with an air source via a ventilation pipe and a valve.

According to this device, by exhausting the air in the lower float, the device loses its buoyancy and is submerged by its own weight, the tip of the trough is located below the water surface, and the clear water flows into the trough and is discharged. It is discharged from the pipe to the outside of the tank.

When air is supplied from the air source into the lower float, the device floats due to buoyancy, the tip of the trough is located above the water surface, and the discharge of the supernatant water is stopped.

[0005]

In the above supernatant water discharge device, the supernatant water is drained from the tip of the trough, and even if scum is collected by the water flow at the time of stirring, the precipitation step is completed and the waste water is discharged. Is separated into supernatant water and activated sludge, then the drainage process is started and scum is discharged.

However, at the end of the precipitation step, the scum collected with great effort diffuses, and even if the scum in the vicinity of the discharge port peripheral area can be discharged, the scum diffused widely throughout the tank is discharged. You cannot do it.
Further, since the above-mentioned supernatant water discharge device is not configured to discharge scum through another discharge pipe, scum discharge and supernatant water discharge are not performed in separate systems, and scum discharge efficiency is poor.

In view of the above facts, it is an object of the present invention to provide a scum discharging device and method for discharging scum on the entire water surface of a batch type activated sludge treatment tank.

[0008]

A scum discharging device according to claim 1 is installed in a single tank in which organic wastewater is treated, and is connected to water intake means for collecting supernatant water and the water intake means. And a supernatant water discharging means for discharging the supernatant water to the outside of the tank, and a water stopping means arranged on the water surface of the tank to prevent the scum floating on the water surface from entering the water intake means,
An agitating means for scraping the scum to the vicinity of the water stopping means by a water flow generated by stirring the organic wastewater, and a scum provided in the water stopping means and discharged by the agitating means to the outside of the tank. And a scum discharging means for doing so.

The scum discharging method according to a second aspect of the present invention is a scum discharging method performed in a single tank in which the organic wastewater is treated, wherein a water flow generated by stirring the organic wastewater is used. It is characterized by including a stirring step of continuously collecting scum in the vicinity of the scum discharging means, and a scum discharging step of discharging scum to the outside of the tank during the stirring step.

[0010]

According to the scum discharging device and the method therefor of the present invention, the organic wastewater flows into a single tank in which the organic wastewater is treated. Next, the sewage in the tank is agitated by the agitating means while the inflow of sewage is continued. At this time, the scum floating on the water surface is scraped by the water flow generated by the stirring means in the vicinity of the water stopping means, and then the scum is sequentially discharged out of the tank by the scum discharging means. Finally, when activated sludge is precipitated from the organic wastewater, the supernatant water is separated. Finally, in the draining step, the supernatant water is discharged from the inside of the tank by the supernatant water discharging means.

As a result, the scum is discharged before the precipitation step, and the scum discharging step and the draining step are separated, so that the scum can be discharged efficiently.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a scum discharging device 10 according to the present invention.
A cross-sectional view of the batch tank 20 in which is used is shown. A disc-shaped scum discharging device 10 is installed at the center of the batch tank 20 (see FIG. 2). This scum discharge device 10
A scum discharge pipe 12 and a supernatant water discharge pipe 14 are connected to the bottom of the scum S, and the scum S and the supernatant water are discharged to the outside of the batch tank 20, respectively. This scum discharge pipe 1
A scum discharge valve 16 for adjusting the discharge amount of the scum S is provided at the portion of the second batch tank 20 projecting outside.

On the other hand, two aeration stirring devices 18 are installed at the bottom of the batch tank 20. This aeration stirring device 18
Is connected to a blower 24 via an air pipe 22, and is configured to send air into the batch tank 20 to aerate and agitate.

As shown in FIGS. 2 and 3, a guide support portion 26 is arranged above the scum discharging device 10.
A pair of guides 28 extending downward and a guide pipe 32 inserted into the clear water drainage pipe 14 are fixed. In addition, in the center of the scum discharge device 10, the clear water drainage weir 3
0 is provided. The supernatant water drainage dam 30 is formed with an intake port 30A for collecting the supernatant water.
A drain port 30B for draining the supernatant water taken from the intake port 30A is formed, and an inclined portion 30C having a downward slope is formed from the drain port 30B side to the supernatant water drain pipe 14 side. As a result, the supernatant water drainage pipe 30 is configured so that the supernatant water overflowing from the drain port 30B can flow out to the supernatant water drain pipe 14, and functions as a supernatant water intake means.

An upper float 36 is installed around the clear water drainage dam 30. Also, a lower float 38 is installed below the supernatant water drainage dam 30.
The upper float 36 and the lower float 38 are filled with air, and are configured to lift the supernatant drainage dam 30 by buoyancy. As a result, the side wall 36A of the upper float 36 can protrude beyond the water surface, and thus the side wall 36A functions as a water stop means for preventing the scum S floating on the water surface from entering the clear water drainage dam 30. The upper float 36 and the clear water drainage dam 30 are connected by a wing nut 42 and a bolt 44 via a support plate 40.

A scum discharge dam 46 is provided on the outer circumference of the upper float 36. This scum discharge weir 46
Is arranged below the water surface so that scum floating on the water surface can flow in and be discharged to the scum discharge pipe 12. Further, the upper portions of the scum discharge pipe 12 and the supernatant water discharge pipe 14 are formed of bellows type pipes and can be expanded and contracted according to the water level of the batch tank 20. As a result, the scum discharging device 10 can be moved up and down depending on the water level, and is guided by the guide 28 and the guide pipe 32 at that time (from the position shown by the imaginary line to the position shown by the solid line in FIG. 3). It can be expanded and contracted.)

The scum discharging device 10 having the above structure operates as follows. Note that FIG. 4 shows an example of a time schedule of the wastewater treatment process of the batch tank 20.

First, sewage is made to flow into the batch tank 20 (sewage inflow process). Next, while continuing the inflow of the sewage, the aeration stirring device 18 stirs the sewage in the batch tank 20, and air is supplied from the blower 24 to aerate the sewage (aeration stirring step). Next, the air supply from the blower 24 is stopped and the aeration stirring device 18 stirs the waste water in the batch tank 20 (stirring step). As a result, a water flow is generated on the water surface in the direction of the scum discharging device 10, and the scum S floating on the water surface is washed away near the scum discharging device 10.

When the scum discharge valve 16 is opened, the scum S flows into the scum discharge pipe 12 from the scum discharge dam 46 and is sequentially discharged to the outside of the batch tank 20 (scum discharge step). At this time, as shown in FIG. 2, the tip of the supernatant water discharge weir 26 is arranged to be higher than the water surface.

After the discharge of the scum S is completed, the scum discharge valve 16 is closed. The sewage inflow process, the aeration and agitation process, the agitation process, and the scum discharge process are repeated four times, and then the sewage inflow is stopped. Next, sewage is precipitated and separated into supernatant water and activated sludge (precipitation step). Next, when the supernatant water is taken from the intake port 30A, the supernatant water overflowing from the drain port 30B flows into the supernatant water drain pipe 14 through the inclined portion 30C and is discharged to the outside of the batch tank 20 (the supernatant water drainage). Process). These sewage treatment steps are configured so that one cycle is completed in about 6 hours, and after the completion of one cycle, the same sewage treatment step is repeated.

As described above, in this embodiment, the batch tank 2
The waste water in 0 is aerated and agitated by the aeration and agitation device 18, and the scum S floating on the water surface of the batch tank 20 is scraped near the scum discharge weir 46.
The scum S in the entire area can be discharged. Moreover, since the scum S does not flow into the supernatant water drain pipe 14, the discharge of the scum S and the discharge of the supernatant water are performed separately, and the scum S can be discharged efficiently, and at the same time, the scum S can be discharged.
Can be easily transferred to the subsequent process such as further processing.

[0022]

As described above, according to the present invention, scum floating on the water surface is continuously collected by the water flow generated by operating the stirring means, and then the scum is discharged out of the tank. The scum can be discharged over the entire area of the batch tank, and the scum can be discharged and the supernatant water can be discharged separately, so that the scum can be discharged efficiently.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a batch tank in which a scum discharging device according to the present invention is used.

2 is a view of the scum discharging device according to the present invention shown in FIG.
It is a top view of 2 line.

3 is a view of the scum discharging device according to the present invention shown in FIG.
It is sectional drawing of 3 line.

FIG. 4 is a process diagram showing a time schedule of a sewage treatment process of a batch tank in which the scum discharging device according to the present invention is used.

[Explanation of symbols] S scum 10 scum discharge device 12 scum discharge pipe (scum discharge means) 14 supernatant drainage pipe (clear water discharge means) 16 scum discharge valve (scum discharge means) 18 aeration stirring device (stirring means) 20 times Tank (single tank) 30 Clear water drainage (water intake means) 30A Drain port (water intake means) 30B Water intake (water intake means) 30C Inclined part (water intake means) 36 Upper float (water stop means) 36A Side wall (water stop) Means) 46 scum discharge weir (scum discharge means)

Claims (2)

[Claims] 1. A water intake means installed in a single tank in which organic wastewater is treated, for taking supernatant water, and a supernatant water discharge communicating with the water intake means for discharging the supernatant water to the outside of the tank. Means, a water stop means arranged on the water surface of the tank to prevent invasion of scum floating on the water surface into the water intake means, and a water flow generated by stirring the organic wastewater to stop the scum water Scum discharge means for discharging the scum scraped up by the stirring means to the outside of the tank, the scum discharge means being provided for the water stopping means apparatus. 2. A scum discharging method carried out in a single tank in which organic wastewater is treated, wherein scum is continuously provided in the vicinity of the scum discharging means by utilizing a water flow generated by stirring the organic wastewater. And a scum discharging step of discharging scum to the outside of the tank during the stirring step.