JP3819149B2 - Aerobic sewage treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a treatment apparatus for high-concentration organic sewage discharged from the livestock industry or food processing industry.
[0002]
[Prior art]
For purification treatment of organic sewage, a method using activated sludge has been conventionally used. In this method, activated sludge, which is an aggregate of useful microorganisms that contribute to the decomposition of organic matter contained in organic wastewater, is aerated with an aeration device for supplying oxygen necessary for the activity of useful microorganisms in the activated sludge. It is stored in a tank, sewage is added to the aeration tank, and organic matter in the sewage is aerobically (oxidized) decomposed by useful microorganisms in the activated sludge. The water to be treated is discharged out of the aeration tank due to overflow, and the supernatant obtained by settling and separating activated sludge in the settling tank is discharged out of the system. A part of the activated sludge separated and separated is returned to the aeration tank for the purpose of increasing the sludge concentration in the aeration tank.
[0003]
When a relatively high concentration of sewage is aerobically treated, such as a human waste treatment plant, bubbles generated by aeration often become a problem. In general, aeration tanks have vents for releasing aerated air and drainage outlets for purified water to be discharged out of the system due to overflow. Bubbles overflow from the vents and drains and cause secondary pollution. Furthermore, when this phenomenon becomes remarkable, most of the treated sewage in the aeration tank overflows out of the tank as bubbles, and normal treatment operation may become impossible.
[0004]
Conventionally, foam generated on the surface of the aeration tank is destroyed by a mechanical defoaming device or spray defoaming device installed on the water surface, and at the same time a drooping wall is provided in front of the drain port to prevent foam overflow. Yes.
[0005]
[Problems to be solved by the invention]
However, the following problems remain in the hanging wall. In the conventional aerobic sewage treatment apparatus shown in FIG. 1, an aeration blower 6 and an aeration apparatus 7 are installed in an aeration tank 1, and bubbles 12 generated by aeration are defoamed by an antifoaming apparatus 5. Prevents outflow. At the same time, a hanging wall 8 is installed in front of the overflow port 4 to prevent the overflow of bubbles. When the raw sewage water 10 is injected, the water to be treated 11 naturally flows out from the overflow port 4 as the water level in the aeration tank rises.
[0006]
When bubbles are generated on the surface of the aeration tank, a water level drop 9 corresponding to the generated bubbles occurs at the aeration tank water level. The water level drop varies depending on the density of the foam, and becomes larger in the case of a creamy dense foam. When processing very high concentrations of sewage with an organic matter concentration of several percent, the required amount of aeration also increases, especially when the quality of the treated sewage in the aeration tank deteriorates due to any change in operating conditions. As shown in Fig. 2, the entire aeration tank is filled with cream-like foam with a density close to that of water, and the foam under the dripping wall overflows and flows out of the system. Resulting in. If the sewage raw water 10 is further injected in such a state where the normal operation is not performed, the quality of the treated sewage 13 is further deteriorated, the generation of bubbles is increased, and the operation is finally impossible.
[0007]
The object of the present invention is to maintain a stable treatment operation by preventing the outflow of foam even in the case of significant foam generation due to some change in operating conditions in a sewage treatment apparatus for treating high-concentration organic sewage. An object is to provide a possible aerobic sewage treatment apparatus.
[0008]
[Means for Solving the Problems]
That is, in order to solve the above-mentioned problem, the aerobic sewage treatment apparatus of the present invention forms a treated water intake that allows the upper portion of the side wall to function as a hanging wall on the aeration tank side wall, and is located higher than the intake. A drainage facility that has a substantially U-shaped channel that has an overflow port at the drain side end and applies an internal pressure to the water intake due to a difference in water level is connected to the water intake .
[0009]
In addition, as organic sewage to be treated according to the present invention, particularly high-concentration sewage in which the generation of bubbles is remarkable, the concentration of organic matter discharged from the livestock industry and food processing industry is several percent, It is not limited to this, It can use also with respect to organic waste water whose organic substance density | concentration is 1% or less.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the apparatus of FIG. 3 which shows 1st Embodiment is provided with the water intake 2 in the side wall of the box-type aeration tank 1, and this water intake 2 has the substantially U shape which has the overflow port 4 in the drain side edge part. The drainage equipment 3 provided with the shape flow path 3a is connected. The overflow port 4 of the drainage facility 3 is positioned higher than the water intake port 2. Further, the aeration tank 1 is provided with an aeration blower 6 and an air diffuser 7, and bubbles 12 generated by aeration are defoamed by the defoaming apparatus 5 to prevent outflow from the tank. The side wall of the aeration tank 1 above the intake port 2 functions as a drooping wall 8 to prevent foam overflow. When the raw sewage water 10 is injected, the water to be treated 11 naturally flows out from the overflow port 4 as the water level in the aeration tank rises.
[0011]
As shown in FIG. 4, when processing very high concentration sewage with an organic substance concentration of several percent, especially when the quality of the sewage in the aeration tank deteriorates due to some change in operating conditions. The entire aeration tank 1 is filled with cream-like foam 12 having a density close to that of water. At this time, since aeration is not performed in the drainage facility 3, the water to be treated 14 is present in the U-shaped flow path 3a. The internal pressure is applied to the water intake port 2 due to the difference in water level between the water intake port 2 side and the overflow port 4 side of the sealed water 14 to be treated, and the foam 12 can be prevented from flowing out by water sealing. Normal operation is maintained. Furthermore, even if the raw sewage water 10 is injected in this state, the treated sewage that has flowed into the drainage facility 3 accompanied with bubbles is separated from the bubbles when moving through the treated water 14 that has been sealed, and is overflowed. Normal operation is maintained by flowing out as treated water 11 from 4.
[0012]
In actual implementation, in the drainage facility 3, by setting the height difference between the bottom of the drainage facility 3 and the intake port 2 and the difference in height between the intake port 2 and the overflow port 4, it is aerobic suitable for the sewage to be treated. It becomes possible to constitute a sewage treatment apparatus.
[0013]
Next, the apparatus of FIG. 5 which shows 2nd Embodiment is provided with the water intake 2 in the side wall of the vertical cylindrical aeration tank 20, and has the overflow port 4 in this water intake 2 and the drain side edge part. The U-shaped pipe 21 is connected as a drainage facility, and the other configuration is the same as that of the first embodiment.
[0014]
Incidentally, when the waste sewage (BOD 40,000ppm) generated from the garbage treatment plant was processed using this device, a lot of cream-like foam was generated, but the bottom of the substantially U-shaped pipe 21 and the water intake port. By setting the height difference L1 of No. 2 to 40 cm and the height difference L2 of the intake port 2 and the overflow port 4 to 10 cm, the loss of bubbles was prevented and a favorable treatment operation could be performed.
[0015]
Furthermore, the apparatus of FIG. 6 showing the third embodiment is one in which a large flow path area is given to the bottom of the drainage facility 3 so that the drainage facility 3 functions as the sludge settling tank 22. Is configured in the same manner as in the first embodiment.
[0016]
Incidentally, when the same raw garbage sewage as above was treated using this apparatus, the sludge 23 did not block the drainage equipment 3 and only the clear supernatant flowed out from the overflow port 4 as the treated water 11. .
[0017]
【The invention's effect】
According to the aerobic sewage treatment apparatus of the present invention, the foaming of the aeration tank is filled with creamy foam by the water sealing action of the water to be treated enclosed in the drainage facility having a substantially U shape. Outflow can be prevented and normal operation can be continued. At the same time, even if the raw sewage water is continuously injected in the above operation state, the treated sewage accompanied by bubbles is separated from the bubbles when moving through the water to be treated enclosed in the drainage facility having a substantially U shape. Since it flows out of the system, normal operation can be continued.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional explanatory diagram of a conventional aerobic sewage treatment apparatus.
FIG. 2 is a schematic cross-sectional explanatory view showing a treatment state by a conventional aerobic sewage treatment apparatus.
FIG. 3 is a schematic cross-sectional explanatory view showing a first embodiment of the aerobic sewage treatment apparatus of the present invention.
FIG. 4 is a schematic cross-sectional explanatory view showing a treatment state by the aerobic sewage treatment apparatus of the present invention according to the first embodiment.
FIG. 5 is a schematic cross-sectional explanatory view showing a second embodiment of the aerobic sewage treatment apparatus of the present invention.
FIG. 6 is a schematic cross-sectional explanatory view showing a third embodiment of the aerobic sewage treatment apparatus of the present invention.
[Explanation of symbols]
1: Aeration tank 2: Water intake 3: Drainage equipment
3a: substantially U-shaped channel 4: overflow port 5: defoaming device 6: aeration blower 7: aeration device 8: dripping wall 9: water level drop
10: Raw sewage
11: treated water
12: Bubble
13: Treated sewage
14: Sealed water to be treated
20: Vertical cylindrical aeration tank
21: U-shaped pipe
22: Sludge settling tank
23: Sludge
L1: Height difference between the approximately U-shaped pipe and the water intake
L2: Height difference between intake and overflow

Claims (1)

Pressure in the aeration tank side wall, while Katachi設the treated water intake that allowed to function as a wall hanging the upper portion of the side wall, have a overflow port to the drainage end portion of the higher the intake position, the intake by the water level difference An aerobic sewage treatment apparatus, wherein a drainage facility having a substantially U-shaped flow path for applying aeration is connected to the intake port.

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