JPH04222695A - Biological treating tank - Google Patents

Abstract

PURPOSE:To improve the efficiency of sludge sedimentation through the provision of a waste liquid upward passage defined by a first partition formed inside a biological treating part, a waste liquid downward passage separated from the waste liquid upward passage by a second partition and a sludge settling part defined by a third partition at the lower part of the biological treating part in communication with the lower part of the waste liquid downward passage. CONSTITUTION:Organic matter in a waste liquid is biologically treated at a biological treating part 10 and introduced through a waste liquid upward passage 11 and a waste liquid downward passage 12 into a sludge settling part 13. Since the treating part 10 and the settling part 13 are separated from each other by a third partition 9 and thus a direct mixing of the waste liquids therebetween is hindered, the sludge deposited in the settling part 13 is not driven up into the treating part 10 to improve the efficiency of sludge sedimentation. Since an extension 5 from the lower end of a second partition 5 is also provided, the waste liquid can be sent into the deep areas of the settling part 13, whereby the separation of the liquid being treated from the sludge can be accelerated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological treatment tank used for treating organic wastewater such as sewage.

0002

BACKGROUND OF THE INVENTION The so-called activated sludge method is known as a method of separating and removing pollutant components in sewage and converting the sewage into clear and safe water. In this system, activated sludge mainly composed of microorganisms is mixed with sewage flowing into an aeration tank, and compressed air is injected from the bottom in the form of bubbles. In this way, the sewage and activated sludge are mixed and stirred, and the activity of aerobic microorganisms in the activated sludge is increased by oxygen in the air, resulting in floating,
Aggregates, adsorbs, and oxidizes soluble microorganisms.

[0003] As an aeration tank used for such purposes,
For example, an aeration tank schematically shown in FIG. 3 is known. That is, for example, a substantially cylindrical partition wall 22 is provided inside the tank 21, and the inside of the tank 21 is generally divided into a biological treatment section 10, a sludge settling section 13, and a treated water ascending passage 15 by this partition wall 22. Then, the wastewater such as sewage is transferred to the biological treatment section 10 as shown by arrow A.
This wastewater is mixed with activated sludge and
Air is supplied from an aeration device 8 installed at the bottom of the biological treatment section 10. The wastewater after the biological treatment is sent to the sludge settling section 13, where the sludge in the wastewater is deposited, and the treated water separated from the sludge rises in the treated water ascending path 15 as shown by arrow G. After that, the treated water that has reached the water level 7 is transferred to the treated water receiving part 21.
a, and is discharged outside the device as shown by arrow H. Sludge is removed from the bottom of the tank 21 at any time as indicated by arrow F. In addition, in the figure, 6 is a sludge scraper.

0004

[Problems to be Solved by the Invention] However, in the apparatus shown in FIG.
The sludge sedimentation efficiency decreases. Furthermore, it is necessary to return the activated sludge to the biological treatment section 10.

[0005] An object of the present invention is to improve the sludge settling efficiency by preventing the sludge deposited in the sludge settling section from being rolled up, and to eliminate the need for returning activated sludge to the biological treatment tank or to minimize the need for returning activated sludge to the biological treatment tank. The objective is to provide a wastewater treatment device that can

[0006]

[Means for Solving the Problems] The present invention provides a biological treatment section that mixes activated sludge containing aerobic microorganisms with wastewater flowing into the biological treatment section, and biologically treats organic matter in this wastewater; an air diffuser disposed within the biological treatment section for blowing air into the biological treatment section; a wastewater rise path separated from the biological treatment section by a first partition wall, which raises the wastewater after the biological treatment; a wastewater descending path separated from the wastewater ascending path by a second partition wall for lowering the wastewater that has risen to the upper end of the wastewater ascending path; a sludge settling section formed below the biological treatment section, the sludge settling section being isolated from the biological treatment section by a third partition and communicating with the lower end of the wastewater descending path; The present invention relates to a biological treatment tank having a treated water rising path for raising the treated water after passing through the biological treatment section, the treated water rising path being isolated from the biological treatment section by a fourth partition.

[0007]

Embodiment FIG. 1 is a schematic diagram showing a biological treatment tank according to an embodiment of the present invention. This device will be explained below mainly according to the flow of wastewater.

Inside the tank 1, there are generally a biological treatment section 10, a wastewater ascending passage 11, a wastewater descending passage 12, and a sludge settling section 1.
3 and a treated water rising path 15. First, on the upper side of the tank 1, there is a biological treatment section 1 having a cylindrical shape, for example.
0 is provided, and wastewater is injected into this biological treatment section 10 as shown by arrow A. In the biological treatment section 10, activated sludge containing aerobic microorganisms is mixed with wastewater, and organic matter in the wastewater is subjected to biological treatment. At the bottom of the biological treatment section 10,
An air diffuser 8 is installed to blow air into the wastewater.

[0009] The wastewater flowing in the biological treatment section 10 as shown by arrow B then rises in the wastewater ascending path 11. This wastewater ascending path 11 is provided inside the biological treatment section 10 and is separated from this by the first partition wall 4.

Next, when the wastewater rising in the wastewater ascending passage 11 reaches the upper end of the wastewater ascending passage 11, it flows over the second partition wall 5 as shown by arrow C and descends within the wastewater descending passage 12. The wastewater ascending passage 11 and the wastewater descending passage 12 are separated by a second partition wall 5.

A sludge settling section 13 is formed below the biological treatment section 10, the wastewater ascending passage 11, and the wastewater descending passage 12. The biological treatment section 10, the wastewater ascending path 11, and the sludge settling section 13 are separated from each other by a third partition wall 9,
Direct wastewater flow is blocked. Further, the lower end of the wastewater descending passage 12 communicates with the sludge settling section 13 , and the wastewater flowing down the wastewater descending passage 12 flows into the sludge settling section 13 . Furthermore, an extending portion 5 a is formed at the lower end of the second partition 5 so as to extend beyond the third partition 9 .

A sludge scraper 6 is installed in the sludge settling section 13, and sludge is removed from the bottom of the tank 1 as indicated by arrow F.

A fourth partition wall 2 is provided on the outside of the biological treatment section 10.
A treated water rising path 15 is provided across the sludge settling section 13, and the lower end of the treated water rising path 15 communicates with the outer peripheral portion of the sludge settling section 13. Therefore, the wastewater flowing down inside the wastewater descending path 12 is
The treated water passes through the sludge settling part 13 as shown by arrow D, and is finally separated from the sludge. The treated water rises in the treated water rising path 15, and then overflows as shown by arrow E and enters the treated water receiving part 1a. , from which it is discharged, for example, discharged as shown by arrow H.

A skirt 2a is formed at the lower end of the fourth partition wall 2 and extends further downward from the joining position with the third partition wall 9. The third partition wall 9 is provided with one or more gas vents 3 with check valves. In addition, 7 in the figure
is the water level.

According to the biological treatment tank according to this embodiment, the biological treatment section 10 and the sludge settling section 13 are separated by the third partition wall 9, thereby preventing direct exchange of wastewater between them. Therefore, the sludge deposited in the sludge settling section 13 is not rolled up to the biological treatment section 10, and therefore, the sludge settling efficiency can be improved.

[0016] Furthermore, a first partition wall 4 is provided to separate the wastewater ascending path 1.
1 and wastewater descending path 12 are formed, and the wastewater after biological treatment is raised and lowered and sent to the pollution sedimentation tank, so the return of sludge to the biological treatment section 10 can be abolished or the amount of this return can be minimized. Wastewater can be treated even in small quantities.

Furthermore, a skirt 2a is provided at the lower end of the fourth partition wall 2.
, various gases such as sludge putrefaction gas gather in the upper space 20 of the sludge settling section 13. Therefore, by removing the gas collected in the upper space 20 from the gas vent 3 equipped with a check valve, the gas in the sludge settling section 13 can be effectively vented, and this gas causes the sludge to float into the treated water ascending path 15. You can prevent this from happening.

Moreover, an extending portion 5a is provided at the lower end of the second partition wall 5.
is provided, the wastewater can be sent into a deeper region of the sludge settling section 13 compared to the case where the extension section 5a is not provided. The passage distance through the sludge to reach the lower end, that is, the filtration distance is long, so separation of the treated water from the sludge can be further promoted. Also, for the same reason, tank 1
Even if the entire device is downsized, the filtration distance can be increased to some extent.

[0019] From the above results, it is possible to obtain treated water that is cleaner than before, and the treatment efficiency is improved compared to conventional treatment equipment, and the installation area of the wastewater treatment equipment is thereby reduced. It also becomes possible.

[0020] Below, wastewater treatment experiments were conducted using the wastewater treatment apparatuses shown in FIGS. 1 and 2, respectively. The properties of the raw wastewater are BOD 100~150mg/l, SS 150~
It was 200mg/l. Figure 1 shows the same scale of this raw wastewater.
and supplied to the wastewater treatment equipment shown in Figure 2 and operated. As a result, the properties of the treated water were as follows.

[0021]

[Effects of the Invention] According to the biological treatment tank according to the present invention, the biological treatment section and the sludge settling section are separated by the third partition wall,
Since this prevents direct exchange of wastewater between the two, the sludge deposited in the sludge settling section is not rolled up to the biological treatment section, and therefore the sludge settling efficiency can be improved.

[0022] Furthermore, a wastewater ascending passage separated from the biological treatment section by the first partition wall is provided, and the wastewater after biological treatment is allowed to rise within this wastewater ascending passage, and then the wastewater that has risen to the upper end of the wastewater ascending passage is discharged. Since the sludge is lowered and sent to the sludge settling section, biological treatment of wastewater can be performed even if the sludge is not returned to the biological treatment section or the amount of sludge returned is reduced to a very small amount.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a biological treatment tank according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a biological treatment tank according to a conventional example.

[Explanation of symbols]

1, 21 Tanks 1a, 21a Treated water receiving section 2 Fourth partition 2a Skirt extending to the lower end of the fourth partition 3 Gas vent with check valve 4 First partition 5 Second partition 5a Second partition Extended portion at the lower end 6 Sludge scraper 7 Water level 8 Aeration device 9 Third partition wall 10 separating the biological treatment section and sludge settling section Biological treatment section 11 Wastewater ascending passage 12 Wastewater descending passage 13 Sludge settling section 15 Treated water rising path 20 Upper space of sludge settling section A, B, C, D Wastewater flow E, G, H Treated water flow separated from sludge F
Sludge removal

Claims (1)

[Claims] [Claim 1] Activated sludge containing aerobic microorganisms;
A biological treatment unit that mixes wastewater flowing into the biological treatment unit and biologically treats organic matter in the wastewater; an aeration device disposed within the biological treatment unit to blow air into the wastewater; the biological treatment unit; a wastewater riseway for raising the wastewater after the biological treatment, the wastewater riseway being separated by a first partition wall from the wastewater riseway; A descending path for lowering the wastewater that has risen to the upper end of the wastewater ascending path; a sludge settling section formed below the biological treatment section; a sludge settling section separated by a third partition wall and communicating with the lower end of the wastewater descending channel; and a treated water rising channel for raising the treated water after passing through the sludge settling section, the biological treatment section A biological treatment tank having a treated water rising path separated from the water by a fourth partition wall.