JPH0671291A - Sewage treatment equipment using packed layer - Google Patents

Abstract

PURPOSE:To provide sewage treatment equipment where sewage is highly treated with high denitrification efficiency without requiring a wide space and a pump of large capacity. CONSTITUTION:A tank body 1 is halved for an aerobic tank 4 and an anaerobic tank 5 with a vertical partition 2. A support layer 6 is installed in the bottom part to support each of the packed layers 7, 8. The aerobic tank 4 uses the inflow side of water to be treated and a U-shaped passage 12 is provided adjacent to the anaerobic tank 5 and an ozone feeder 13 is installed in the lower part of the passage 12. The anaerobic tank 5 uses the outflow side of water to be treated and digestion liquid is circulated to the aerobic tank 4 side through a flow part 14 at the upper end of the partition 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment apparatus using a packed bed capable of performing advanced treatment of sewage using a limited space.

[0002]

2. Description of the Related Art In recent years, social demands for advanced treatment of sewage have been increasing. Immediate targets for advanced treatment of sewage are nitrogen and phosphorus for preventing eutrophication of water bodies, and in addition, BOD, COD, SS and the like. Of these, BOD and SS can be removed to a large extent by "biofilm filtration" in which the water to be treated flows downward from the top of the aerobic packed bed. It is preferable to use an anaerobic packed bed and an aerobic packed bed for performing nitrification denitrification, and the process for this is also researched.

FIG. 3 shows a typical example of an apparatus studied for performing such nitrification denitrification. An aerobic tank 21 and an anaerobic tank 22 filled with particles having a specific gravity of more than 1. Is provided independently, and first, the water to be treated is allowed to flow downward in the aerobic tank 21.
The anaerobic tank 22 is used to remove the water to be treated from below the aerobic tank 21 by the pump 23.
Is a system in which the anaerobic tank 22 is allowed to flow downward in addition to being transferred to the upper part of the. However, the conventional sewage treatment equipment as shown in FIG. 3 requires a large area as a site, and it becomes very difficult to secure an extra space for advanced treatment at the existing sewage treatment plant in the urban area. Therefore, there is a problem that it cannot be easily adopted. Further, this sewage treatment device also has a problem that a large capacity pump is required.

As shown in FIG. 4, the tank 24 is filled with particles having a specific gravity of less than 1 to form an anaerobic layer 25 in the lower part and an aerobic layer 26 in the upper part, and the water to be treated as an upward flow. A part of the treated water that flows out from the upper part of the tank 24 is pumped 27
The so-called “nitrifying solution circulation system” for circulating the anaerobic layer 25 has also been studied. The device of Fig. 4 has the advantage that the installation space is relatively small, but a part of the nitrification liquid in the aerobic layer 26 flows out as it is as treated water, so 100% denitrification is theoretically possible. In addition, there is a problem that a large-capacity pump is required for circulating the nitrifying solution.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, does not require a wide space or a large capacity pump, and can perform advanced treatment of sewage with a high denitrification rate. It has been completed to provide a sewage treatment apparatus using the.

[0006]

A first aspect of the present invention, which has been made to solve the above-mentioned problems, divides the inside of the tank body into two parts by a vertical partition wall having a circulation portion at the lower end, and divides the inside of the treated water inflow side. An aerobic tank and an anaerobic tank on the outflow side are provided, and a support layer is provided at the bottom of the tank body to support the packed layers on the aerobic tank side and the anaerobic tank side, respectively, and in a position directly above the support layer of the aerobic tank. An air supply pipe is provided, a methanol injection pipe is provided directly above the support layer of the anaerobic tank, a U-shaped flow path is provided adjacent to the anaerobic tank, and an ozone supplier is provided below the U-shaped flow path. It is a thing. A second invention for solving the same problem divides the inside of the tank body into two by a vertical partition having a circulation portion at the lower end and the upper end, and divides the anaerobic tank on the inflow side of the treated water and the aerobic tank on the outflow side. As a tank, a supporting layer is provided at the bottom of the tank to support the filling layers on the aerobic tank side and the anaerobic tank side respectively, and an aeration pipe is installed directly above the supporting layer of the aerobic tank to the anaerobic tank. A methanol injection pipe is provided at the inflow portion of the untreated water.

[0007]

EXAMPLES Each invention will be described in more detail below with reference to examples. FIG. 1 is a diagram showing an embodiment of the first invention.
Is a vertical partition wall that divides the inside of the tank body, 2 is a vertical partition wall, and 3 is a distribution portion formed at the lower end of the tank body having a height of about 20 to 30 cm and a width of the entire tank body 1. The inside of the tank body 1 is divided by a partition wall 2 into an aerobic tank 4 on the inflow side of the water to be treated and an anaerobic tank 5 on the outflow side. A support layer 6 of about 50 cm is formed. The water to be treated flows in the aerobic tank 4 as a downward flow, flows horizontally in the support layer 6 into the anaerobic tank 5, and then flows in the anaerobic tank 5 as an upward flow.

In both the aerobic tank 4 and the anaerobic tank 5, packing layers 7 and 8 are supported on a supporting layer 6. Packing layers 7, 8
Is a granular filler, and a biofilm is formed on the surface of the filler. An aeration pipe 9 is provided directly above the support layer 6 of the aerobic tank 4 to diffuse oxygen into the aerobic tank 4 to supply oxygen. On the other hand, a methanol injection pipe 10 is provided immediately above the support layer 6 of the anaerobic tank 5 so that the denitrifying bacteria adhering to the packed layer 8 of the anaerobic tank 5 are supplied with a hydrogen donor necessary for denitrification. It has become. Further, at the bottom of the support layer 6, an air + water pipe 11 for cleaning the filling layers 7 and 8 is provided all over.

A U-shaped flow path 12 is provided at a position adjacent to the anaerobic tank 5.
Is provided, and an ozone supplier 13 is provided below it. Therefore, the treated water flowing out from the upper end of the anaerobic tank 5 receives the diffused ozonized air while flowing through the U-shaped channel 12.

In the sewage treatment apparatus using the packed bed of the first aspect of the invention constructed as described above, first, the water to be treated is made to flow in the aerobic tank 4 as a downward flow, and while it is made to flow down the packed bed 7, Kjeldahl. Nitric acid is nitrified into nitrate nitrogen. Further, BOD is aerobically decomposed, and SS is captured by the packed bed 7 and removed. Next, the water to be treated flows horizontally in the support layer 6, enters the anaerobic tank 5, and flows as an upward flow between the packed layers 8 of the anaerobic tank 5. During this period, the nitrate nitrogen is denitrified by the denitrifying bacteria adhering to the packed bed 8. Thereafter, the water to be treated is supplied with ozone from the ozone supplier 13 while flowing through the U-shaped channel 12, sterilizes the treated water, imparts dissolved oxygen, removes COD,
Chromaticity removal is achieved.

In the sewage treatment apparatus using the packed bed of the first aspect of the present invention, nitrification and denitrification are sequentially carried out, and therefore, in principle, nitrogen is removed.
There is an advantage that 100% can be removed, and aerobic tank 4
Is advantageous because the packed bed 7 is highly stable. Further, unlike the conventional device shown in FIG. 3, there is an advantage that the installation space can be reduced and a pump is not required.

FIG. 2 is a view showing an embodiment of the second invention, in which the inside of the tank body 1 is divided into two by a vertical partition wall 2, and a support layer 6 made of gravel or the like is provided at the bottom of the tank. It is the same as that of the first aspect of the invention, but the circulation part 3 is formed at the lower end of the partition wall 2 and the circulation part is also formed at the upper end thereof.
14 are formed. Further, in the second invention, contrary to the first invention, the treated water inflow side is the anaerobic tank 5, and the outflow side is the aerobic tank 4. It should be noted that an air diffuser pipe 9 is provided directly above the support layer 6 of the aerobic tank 4, and an air + water pipe 11 for washing the filling layers 7 and 8 is provided at the bottom of the support layer 6. That is also the same as the first invention.

In the sewage treatment apparatus using the packed bed according to the second aspect of the present invention constructed as above, a difference in density is generated between the anaerobic tank 5 and the anaerobic tank 5 due to air diffusion in the aerobic tank 4, and this becomes a driving force. In the aerobic tank 4, the water to be treated floats and in the anaerobic tank 5, a downward circulation occurs. The circulation amount from the aerobic tank 4 to the anaerobic tank 5 can be adjusted by changing the height of the upper end of the partition wall 2. In this case, the circulation rate, which is expressed as circulating water volume / inflow water volume, is about 400% due to equipment restrictions.

After the water to be treated is supplied with methanol, it flows downward in the anaerobic tank 5 together with the nitrifying solution from the aerobic tank 4 by the denitrifying bacteria adhering to the packed bed 8 to produce nitrate nitrogen. Is denitrified. At this time, BOD in the water to be treated
If present, BOD is used as part of the hydrogen donor for denitrification and removed, and SS is packed bed 8 of anaerobic tank 5.
Are captured and removed by. The water to be treated that has passed through the anaerobic tank 5 flows horizontally through the support layer 6 into the aerobic tank 4, and flows in the aerobic tank 4 as an upward flow. During this period, the remaining BOD and methanol are aerobically decomposed, a part is discharged as final treated water, and a part is circulated to the anaerobic tank 5.

The sewage treatment apparatus using the packed bed according to the second aspect of the present invention can achieve a denitrification rate of about 80% and can use BOD in the water to be treated as a hydrogen donor during denitrification, so that methanol can be used. 2) Contamination of treated water due to the fact that a pump for circulating the nitrifying solution is not necessary unlike the equipment of Fig. 3 and Fig. 4 and that the final treated water is aerobic and decomposes excess methanol. There is an advantage that there is no fear of this, and that there is no need for equipment for adding oxygen to the treated water. Further, compared with the conventional device shown in FIG. 3, there is an advantage that the installation space can be reduced.

[0016]

As described above, the sewage treatment apparatus using the packed bed of the present invention can be installed in a limited space because the installation space can be reduced as compared with the conventional apparatus. Further, there is an advantage that a large-capacity pump as in the past is not required. Further, according to the first invention, in principle, 100% of nitrogen can be removed, and the advantage that the filling layer 7 is highly stable can be obtained. According to the second invention, a denitrification rate of about 80% can be achieved, BOD in the water to be treated can be used as a hydrogen donor at the time of denitrification, so that the amount of methanol can be reduced. There are advantages such as no possibility of contamination and the fact that no facility is required to add oxygen to the treated water. Therefore, the present invention has an extremely large contribution to the industrial development as a sewage treatment apparatus using a packed bed that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the first invention.

FIG. 2 is a sectional view showing an embodiment of the second invention.

FIG. 3 is a cross-sectional view showing a conventional example.

FIG. 4 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 1 Tank Body 2 Partition 3 Flow Section 4 Aerobic Tank 5 Anaerobic Tank 6 Support Layer 7 Packing Layer 8 Packing Layer 9 Diffusing Pipe 10 Methanol Injection Pipe 11 Air + Water Pipe 12 U-Shaped Channel 13 Ozone Supplyer 14 Flowing Portion

Claims (2)

[Claims] 1. The inside of the tank is divided into two parts by a vertical partition having a circulation part at the lower end to form an aerobic tank on the inflow side of the treated water and an anaerobic tank on the outflow side, and a support layer is provided on the bottom of the tank body. Provided to support the packed layers on the aerobic tank side and the anaerobic tank side respectively, an air diffusion pipe is provided directly above the supporting layer of the aerobic tank, and a methanol injection pipe is provided directly above the supporting layer of the anaerobic tank. At the same time, a U-shaped flow path is provided adjacent to the anaerobic tank, and an ozone supplier is provided below the U-shaped flow path. 2. The inside of the tank is divided into two parts by a vertical partition having a circulation portion at the lower end and the upper end to form an anaerobic tank on the inflow side of the water to be treated and an aerobic tank on the outflow side, which is supported on the bottom of the tank body. A layer is provided to support the packed layers on the aerobic tank side and the anaerobic tank side, respectively, and an aeration pipe is provided directly above the supporting layer of the aerobic tank. A sewage treatment apparatus using a packed bed, which is provided with an injection pipe.