JPH0671290A - Sewage treatment equipment using packed layer - Google Patents

Abstract

PURPOSE:To provide sewage treatment equipment using a packed layer where sewage is highly treated without requiring a wide space and a pump of large capacity. CONSTITUTION:A tank body 1 is separated into the packed layer side and the waterway side by a vertical partition 2. In the packed layer side, an aerobic tank 7 and a anaerobic tank 3 are provided in the upper and lower stages respectively. Water to be treated passes through the packed layer in downward flow, turns at a flow part 3 at the lower end of the partition 2, enters a passage 4, is supplied with oxygen and is discharged. Or water to be treated enters the packed layer at the lower end of an inflow waterway and passes through the layer in upward flow, and then one part thereof is discharged and the other is returned to the inflow waterway.

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 The social demand for advanced treatment of sewage is increasing. The immediate targets of this advanced treatment are nitrogen and phosphorus for preventing eutrophication of water bodies, and also 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 23 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 apparatus of FIG. 4 has an advantage that the installation space is relatively small, but there is also a problem that a large capacity pump is required for circulating the nitrification solution.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and treats sewage using a packed bed capable of performing advanced treatment of sewage without requiring a large space or a large capacity pump. It has been completed to provide a device.

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a case where a tank having a support layer at the bottom is connected to the side of the packing layer by a vertical partition having a circulation section at the lower end. It is divided into the folded flow path side, and the upper part on the packed bed side is filled with particles having a relatively small specific gravity and an aeration pipe is provided to form an aerobic tank, and the lower part on the packed bed side has a specific gravity. It is characterized in that an anaerobic tank is formed by filling a relatively large particle and a methanol injection pipe, and further an ozone or air supply device is provided below the turn-back passage. A second invention for solving the same problem is to divide the inside of a tank having a support layer at the bottom into a packed bed side and an inflow channel side by vertical partition walls having circulation parts at the upper and lower ends to fill the inside. The upper part of the bed side is filled with particles with a relatively small specific gravity and an aeration pipe is provided to form an aerobic tank, and the lower part of the packed bed side is filled with particles with a relatively large specific gravity and is anaerobic. It is characterized in that a tank is formed and the height of the upper end of the vertical partition is variable.

[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 tank body, 2 is a vertical partition wall for partitioning the inside, and 3 is a circulation 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 the partition wall 2 into a packed bed side and a folded flow path 4 side.
A support layer 5 made of gravel or the like and having a thickness of about 50 cm is formed on the bottom of the tank body 1.

The upper part on the packed bed side is packed with particles such as PVA gel particles and anthracite particles having a relatively small specific gravity of 1 to 1.5 and a diameter of about 5 to 15 mm, and is scattered below the packed bed. An air pipe 6 is provided to serve as an aerobic tank 7. The lower part of the packed bed side is filled with particles such as lightweight aggregate having a specific gravity of 1.5 to 2.5 and a diameter of 2 to 10 mm, crushed stone, etc. to form the anaerobic tank 8. A methanol injection pipe 9 is provided above the packed bed of the anaerobic tank 8 so that the hydrogen donor necessary for denitrification is injected into the denitrifying bacteria adhering to the packed bed of the anaerobic tank 7.

An ozone or air supplier 10 is provided in the lower portion of the return passage 4. Therefore, the treated water that flows from the packed bed side through the support layer 5 and into the return flow path 4 is
Ozone or air will be diffused. At the bottom of the support layer 5, an air + water pipe 11 for cleaning the packed bed is provided.
Is provided. In addition, a trough 12 is provided at the upper end of the tank body 1 for collecting cleaning waste water.

In the sewage treatment apparatus using the packed bed of the first invention described above, the water to be treated, which is the supernatant water of the final settling basin, is supplied from the upper part of the tank 1, and the aerobic tank 7 and the anaerobic tank 8 are directed downward. It is made to flow as a flow, is made to flow into the folding flow path 4 through the support layer 5 and the circulation portion 3 at the lower end of the partition wall 2, and is made to flow out as highly treated water from the upper end thereof. In this way, while the water to be treated flows down in the aerobic tank 7, the Kjeldahl nitrogen in the water to be treated is nitrified into nitrate nitrogen. Further, BOD is aerobically decomposed, and SS is captured by the packed bed and removed. Next, the water to be treated flows down the anaerobic tank 8, during which the nitrate nitrogen is denitrified by the denitrifying bacteria adhering to the packed bed.
After that, the water to be treated passes through the support layer 5 and turns back to the flow path 4.
At this time, ozone or air is supplied from the ozone or air supplier 10, and sterilization of treated water, addition of dissolved oxygen, removal of COD, and removal of chromaticity are achieved. 1
The packed bed is backwashed by supplying cleaning water and air from the air + water pipe 11 at a rate of about once a day, but in the aerobic tank 7 and the anaerobic tank 8 Since they have different specific gravities, they spontaneously separate and settle after washing.

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.
Being able to remove 100%, aerobic tank 7 and anaerobic tank 8
The stability of the packed bed at the time of backwashing is high due to the difference in the specific gravity of the particles with, the SS capture capacity is large, and the continuous operation time can be long, unlike the conventional device shown in FIG. There are many advantages such as the reduction, the need for a complete set of air + water piping 11 for bed cleaning, and the need for a pump.

FIG. 2 is a diagram showing an embodiment of the second invention, in which the inside of the tank body 1 is divided into a packed bed side and an inflow water channel 13 side by a vertical partition wall 2. The vertical partition wall 2 has a flow section 3 at the lower end and a flow section 14 at the upper end. The height h of the flow portion 14 at the upper end of the vertical partition wall 2 is variable so that the amount of inflow from the packed bed side into the inflow water channel 13 can be controlled. A support layer 5 made of gravel or the like is formed at the bottom of the tank body 1, and the upper part of the packed bed side has a relatively small specific gravity of 1 to 1.5 and a diameter of 5 to 15
An aerobic tank 7 is prepared by filling particles such as PVA gel particles and anthracite particles having a size of about mm with an air diffusion pipe 6 below the packed bed. The lower part of the packed bed side is filled with particles such as lightweight aggregate having a specific gravity of 1.5 to 2.5 and a diameter of 2 to 10 mm, crushed stone, etc. to form the anaerobic tank 8. At the bottom of the support layer 5, an air + water pipe 11 for washing the packed layers 7 and 8 is provided.

In the sewage treatment apparatus using the packed bed according to the second aspect of the present invention constructed as above, the water in the aerobic tank 7 floats due to the air diffused from the air diffuser pipe 6, and this becomes the propulsive force. On the packed bed side, the water to be treated floats and a downward circulation occurs on the inflow channel 13 side. The circulation amount from the packed bed side to the inflow channel 13 side can be adjusted by changing the height h of the circulation portion 14 at the upper end of the partition wall 2. The upper limit of the upward flow velocity of the liquid in which the water to be treated and the nitrification treated water are mixed is 500 m / day.

The water to be treated is supplied with methanol, and then descends through the inflow channel 13 together with the water that has passed through the aerobic tank 7, passes through the circulation section 3 and the support layer 5, and first enters the anaerobic tank 8. . Here, nitrate nitrogen is denitrified by the denitrifying bacteria adhering to the packed bed and removed as nitrogen gas. At this time, BOD is used and removed as a part of the hydrogen donor for denitrification, and SS is captured and removed by the packed bed of the anaerobic tank 8. The water to be treated that has passed through the anaerobic tank 8 then enters the aerobic tank 7 and flows in the aerobic tank 4 as an upward flow. During this time, the Kjeldahl nitrogen in the water to be treated is nitrified to nitrate nitrogen, part of which is discharged to the outside as final treated water, and part of it is circulated from the inflow water channel 13 to the anaerobic tank 8 as nitrification treated water. In addition, although the cleaning water and air are supplied from the air + water pipe 11 once a day to backwash the packed bed, the aerobic tank 7 and the anaerobic tank 8 are not filled. Due to the different specific gravities of the existing particles, they naturally separate and settle after washing.

The sewage treatment apparatus using the packed bed of the second invention has the advantage that the installation space can be reduced, and
% Denitrification rate can be achieved, and unlike the devices shown in FIGS. 3 and 4, a pump for circulating the nitrifying solution is unnecessary,
Since the final treated water is aerobic, there is no need for a facility for adding oxygen to the treated water, and the air + water pipe 11 for layer washing is a complete set.

[0016]

As described in detail 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 conventional case is not required and the stability of the packed bed at the time of backwashing is high. Further, according to the first invention, it is possible in principle to remove 100% of nitrogen. Further, according to the second invention, there is an advantage that a denitrification rate of about 80% can be achieved and that equipment for applying oxygen to the treated water is unnecessary. 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]

 DESCRIPTION OF SYMBOLS 1 Tank body 2 Partition 3 Flow part 4 Folding flow path 5 Support layer 6 Diffusing pipe 7 Aerobic layer 8 Anaerobic layer 9 Methanol injection pipe 10 Ozone or air supply device 11 Air + water pipe 12 Trough 13 Inflow channel 14 Flow part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C02F 9/00 A 7446-4D

Claims (2)

[Claims] 1. The inside of a tank having a support layer at the bottom is divided into a packed bed side and a folded flow path side by a vertical partition having a circulation section at the lower end, and the specific gravity is relatively high at the packed bed side upper stage section. An aerobic tank is formed by filling small particles with an aeration pipe, and a anaerobic tank is formed by filling the lower part of the packed bed with particles having a relatively large specific gravity and a methanol injection pipe. Further, a sewage treatment apparatus using a packed bed, characterized in that an ozone or air supply device is provided below the folding flow path. 2. The inside of a tank having a support layer at the bottom is divided into a packed bed side and an inflow channel side by vertical partition walls having circulation parts at both upper and lower ends, and the specific gravities of the upper layers on the packed bed side are compared. A small amount of particles and an aeration pipe to form an aerobic tank, and the lower part of the packed bed side is filled with particles with a relatively large specific gravity to form an anaerobic tank. A sewage treatment apparatus using a packed bed, characterized in that the height of the circulation section at the upper end is variable.