JPH09150177A - Waste water treating device sing fluidized bed type deep layer type aerating tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fluidize a deposition carrier with a little energy consumption by inclining a bottom part of an aerating tank toward a side wall and disposing an airlift pipe with a built-in air diffusing mechanism while opening a port near the lowest part. SOLUTION: The bottom part 1b of the aerating tank 1 is inclined downward from a downward stream (1) toward an upward stream (2). Moreover, the airlift pipe 5 is provided at an upward stream direction of an upper of the lowest part 1c. A slope of the bottom part 1b is decided by a capacity of the airlift pipe 5, and it is set in about 1-30degree, preferably in about 5-20degree. The bottom part 1b may be a plane or a curved surface. In this airlift pipe 5, an inlet 5a is formed near the lowest part 1c at which a deposited microorganism immobilizing carrier 4 is collected by a revolving water flow and the slope of the bottom part 1b of the aerating tank 1 and an outlet 5b is formed at an upper part than a jetting port 3a of the air diffusing mechanism 3. The carrier 4 is risen in the airlift pipe 5 by an airlift function and transported with the air diffusing mechanism 3 and discharged from the jetting port 3a by this constitution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to treatment of sewage and wastewater, and more particularly to an aeration tank used for biological treatment of sewage and wastewater.

[0002]

2. Description of the Related Art A deep-layer aeration tank is an aeration tank whose oxygen dissolution efficiency is improved by providing an effective water depth deeper than a normal aeration tank (effective water depth of 4 m to 6 m).

The deep-layer aeration tank is mainly used for sewage treatment with a high BOD volumetric load requiring high oxygen dissolution efficiency, and is space-saving and has a high BOD volumetric load as compared with the case of using an ordinary aeration tank. Can be processed.

The aeration and agitation methods include swirling aeration and aeration using an air diffuser installed in the middle of the water depth, swirling aeration and agitation using an underwater aerator installed at the bottom of the aeration tank, or installed in the aeration tank. Aeration and agitation utilizing the air lift action of the inner cylinder tube is used.

On the other hand, the microorganisms are immobilized at a high concentration on the microorganism-immobilized carrier filled in the aeration tank, and the microorganism concentration in the aeration tank is maintained at a high concentration to save space and achieve high BOD.
A treatment method that enables treatment with a volume load is also known.

A fixed bed system, a moving bed system, a fluidized bed system or the like is used as a carrier filling system. In particular, the fluidized bed system has a contact efficiency between the microorganisms immobilized on the carrier and the mixed liquid in the tank. Is excellent.

Further, it is known that the use of a microorganism-immobilized carrier is effective not only for removing BOD but also for increasing the concentration of useful bacteria having a small growth rate as compared with BOD-assimilating bacteria such as nitrifying bacteria. Has been.

Both the deep layer aeration tank and the fluidized bed aeration tank filled with the microorganism-immobilized carrier are space-saving and have a high BOD.
Although it is a wastewater treatment method that allows treatment under load, a fluidized bed type deep-layer aeration tank combining these two methods has also been disclosed as an invention.

FIG. 5 shows that, in a fluidized bed type deep layer aeration tank 1 having a water depth of about 8 m to 12 m, which is generally used in the past, aeration is performed by an aeration mechanism 3 with a partition wall 2 as a boundary.
The aeration mechanism 3 generates an upward swirling flow from the downward flow B, and aeration is performed while swirling the microorganism-immobilized carrier 4.

[0010]

However, in the swirling flow type fluidized bed type deep layer aeration tank 1 shown in FIG. 5, the swirling water flow generated along with the aeration causes stirring of the mixed liquid and microorganisms in the aeration tank 1. Although the immobilization carrier 4 is fluidized, when the microorganism immobilization carrier 4 having a specific gravity of 1 or more is used, the microorganism immobilization carrier 4 is used as the bottom part 1a of the aeration tank 1.
Therefore, the contact efficiency between the microorganisms immobilized on the immobilized microorganisms-immobilized carrier 4 and the mixed solution in the tank is reduced and the oxygen supply amount to the microorganisms is reduced, resulting in the anaerobicization of the immobilized microorganisms. Deterioration of treated water quality may occur.

This is because the microorganism-immobilized carrier 4 sediments due to the difference in specific gravity between the microorganism-immobilized carrier 4 and water, and the swirling flow at the bottom 1a of the aeration tank is sufficient to raise the microorganism-immobilized carrier 4. And a phenomenon that occurs when there is no direction.

As a method for coping with the deterioration of the fluidity of the microorganism-immobilized carrier 4, it is possible to increase the aeration amount. However, in order to improve the fluidity, an aeration amount more than the air amount required for the biological reaction is required. It is possible to do it. In this case, there is a problem that extra aeration power is consumed as compared with the case where the microorganism-immobilized carrier 4 is not filled.

Therefore, in the fluidized bed type deep layer aeration tank 1 of the swirling type, the aeration amount and the filling rate of the microorganism-immobilized carrier 4 must be set within a range in which sufficient fluidity can be obtained. There is.

The present invention solves the above-mentioned problems associated with the deposition of a microorganism-immobilized carrier in a fluidized bed type deep aeration tank filled with the microorganism-immobilized carrier, and the carrier deposited at the bottom with a small amount of energy consumption. Is intended to flow.

[0015]

[Means for Solving the Problems] The first means for solving the above-mentioned problems is a swirling flow-type deep-layer aeration tank using a microorganism-immobilized carrier, which is inclined toward the side of the aeration tank. A bottom portion, an air lift pipe having an inflow port near the bottom of the bottom portion, and an air diffusing mechanism provided in the air lift pipe,
It is an apparatus for treating wastewater using a fluidized bed type deep layer aeration tank having.

According to the above-mentioned first means, the microorganism-immobilized carrier swirls from a descending flow to an upward flow by an arbitrary swirling flow with the partition wall as a boundary, but the maximum of the corners along the inclined bottom part. Collected at the bottom. The collected microorganism-immobilized carrier is conveyed to the upper part by the air lift pipe, again becomes a downward flow, reaches the bottom part, and circulates in the aeration tank.

Further, by providing an air diffusing mechanism in the air lift pipe, the oxygen supply amount is added, and the air from the air diffusing mechanism enhances the air lift effect to promote the ascending action of the microorganism-immobilized carrier.

A second means for solving the above-mentioned problem is a swirling flow type deep-layer aeration tank using a microorganism-immobilized carrier, and a bottom portion inclined toward a side portion of the aeration tank, and a bottom portion of the bottom portion. A fluidized bed having an air lift pipe having an inflow port near the bottom and an outflow port at the top, an air diffusing mechanism provided in the air lift pipe, and an air diffusing mechanism separately provided at a side portion of the air lift pipe. Method This is a wastewater treatment device that uses a deep-layer aeration tank.

According to the above-mentioned second means, since the air diffusing mechanism is separately provided on the side portion of the air lift pipe, the airlift action is further increased, and the ascending action of the microorganism-immobilized carrier becomes remarkable, so that the swirling is performed. The flow of flow is promoted.

The third means for solving the above-mentioned problems is that the bottom of the aeration tank is inclined downward from the downward flow in the aeration tank in the upward flow direction. The wastewater treatment apparatus using the fluidized bed type deep layer aeration tank according to the means.

According to the above-mentioned third means, the microorganism-immobilized carrier at the bottom of the aeration tank flows along the bottom which is downwardly inclined from the downward flow toward the upward flow direction and reaches the air lift pipe, so that the accumulation action is achieved. Is promoted.

A fourth means for solving the above-mentioned problems is that the bottom of the aeration tank is provided at the corner of the aeration tank. Method This is a wastewater treatment device that uses a deep-layer aeration tank.

According to the above-mentioned fourth means, since the bottom of the aeration tank is provided at the corner of the aeration tank, the accumulation of the microorganism-immobilized carrier becomes close to one point, so that the raising action in the air lift pipe is achieved. Is done efficiently.

A fifth means for solving the above-mentioned problems is characterized in that the bottom of the aeration tank is formed in a V-shape, and the groove of the V-shape is inclined downward toward the side of the aeration tank. The waste water treatment apparatus using the fluidized bed type deep layer aeration tank according to the first or second means.

According to the above-mentioned fifth means, since the bottom has a V-shaped groove-like inclination, the microorganism-immobilized carrier flows to the bottom while accumulating in one place, so that it is accumulated in the air lift pipe. , Further promoted.

[0026]

FIG. 1 is a side sectional view according to an embodiment of the present invention, in which 1 is an aeration tank, 2 is a partition wall, and 3 is a partition wall.
3'is an aeration mechanism. Reference numeral 4 denotes a microorganism-immobilized carrier, and the microorganism-immobilized carrier 4 becomes a downward flow B and an upward flow B in the aeration tank 1 by a swirling flow generated by the air diffusers 3, 3'or a separate swirling means, thereby forming a partition wall 2 It turns around.

According to the present invention, the bottom portion 1b of the aeration tank 1 is inclined downward from the downward flow to the upward flow, and the air lift pipe 5 is provided in the upward flow direction above the bottommost portion 1c of the bottom portion 1b.

The inclination of the bottom 1b of the aeration tank 1 is determined by the speed of the swirling flow and the capacity of the air lift 5, but it is about 1 to 30 degrees, preferably about 5 to 20 degrees. The bottom portion 1b of the aeration tank 1 may be flat or curved.

The shape of the aeration tank 1 may be prismatic or cylindrical, and the depth of the aeration tank 1 may be 12 m or more.

In the air lift pipe 5, the vicinity of the bottommost portion 1 where the accumulated microorganisms-immobilized carrier 4 is collected by the swirling water flow and the inclination of the bottom portion 1b of the aeration tank 1 serves as an inlet port 5a and a jetting port 3a of the air diffusing mechanism 3 rather than the ejection port 3a. The upper part is installed so as to become the outflow port 5b.

Diameter and length of air lift pipe 5 and inflow port 5
The distance between a and the bottom 1c may be set in accordance with the size of the microorganism-immobilized carrier 4 so that the microorganism-immobilized carrier 4 can flow well.

The material of the air lift pipe 5 may be metal, concrete, reinforced plastic or the like having strength.

Fluidized bed type deep layer aeration tank 1 according to the present invention
Then, the deposited microorganism-immobilized carrier 4 is added to the swirling water flow,
The microorganisms-immobilized carriers 4 that flow along the slope of the bottom 1b of the aeration tank 1 and are collected at the bottom 1c are lifted in the airlift pipe 5 by the airlift action of the airlift pipe 5 having the inflow port 5a in the vicinity. , Is conveyed above the jet port 3a of the air diffusion mechanism 3 and is made into a downward flow by the swirling water flow from the outlet port 5b to be conveyed to the bottom part 1b of the aeration tank 1 and a part of the microorganism-immobilized carrier 4 is re-deposited. To do.

Further, if another air diffusion mechanism 3'is installed in the air lift pipe 5, the airlift action is further enhanced, and the raising action of the microorganism-immobilized carrier 4 becomes remarkable.

2 to 4 are perspective views showing various shapes of the bottom portion 1b of the aeration tank 1 according to the present invention.

FIG. 2 is substantially the same as the embodiment of FIG.
It has a structure in which the bottom portion 1b of the aeration tank 1 is inclined in one side direction.

FIG. 3 shows a structure in which the bottom portion 1b of the aeration tank 1 is inclined in the corner direction. According to this embodiment, since the microorganism-immobilized carrier 4 is accumulated at one place, there is an advantage that the raising efficiency in the air lift pipe 5 is improved.

FIG. 4 shows a structure in which the bottom of the aeration tank 1 forms V-shaped groove-shaped inclined surfaces 1b and 1b ', and the bottom of the V-shaped groove is inclined toward the side of the aeration tank 1. Is.

According to this embodiment, the microorganism-immobilized carrier 4 is accumulated in the V-shaped groove while the bottom portion is covered by the air lift pipe 5.
As it flows in the direction, the ascending effect is further promoted, as described above.

[0040]

As described above, according to the present invention, the bottom of the fluidized bed type deep aeration tank is inclined downward from the downward flow to the upward flow, so that the microorganism-immobilized carrier to be deposited can be collected. There is no need to use extra power for.

Since the collected microorganism-immobilized carriers are conveyed to the upper part of the aeration tank by the air lift pipe, the air-lift pipe is installed only for immobilizing the microorganisms deposited at the places where the upward-flowing microorganism-immobilized carriers accumulate. The carrier can easily turn into an upward flow and swirl, and even if the microorganism-immobilized carrier is deposited by repeating a series of flow actions, it is returned to the fluidized state again. It is possible to prevent deterioration of contact efficiency between the immobilized microorganisms and the mixed liquid in the aeration tank.

Further, the air diffusing mechanism in the air lift pipe and the air diffusing mechanism provided together with the air lift pipe promote the upward feeding action of the air lift pipe in addition to the oxygen supply.
Since there is no need for an extra blowing power for carrying the microorganism-immobilized carrier, there is an effect of energy saving.

[Brief description of the drawings]

FIG. 1 is a side sectional view according to an embodiment of the present invention.

FIG. 2 is a perspective sectional view of the present invention.

FIG. 3 is a perspective sectional view according to another embodiment of the present invention.

FIG. 4 is a perspective sectional view according to another embodiment of the present invention.

FIG. 5 is a side sectional view of an aeration tank according to a conventional technique.

[Explanation of symbols]

 1 aeration tank 1b bottom of aeration tank 1c bottom of aeration tank 2 partition wall 3 aeration mechanism 3'aeration mechanism 4 microbial immobilization carrier 5 airlift pipe a downward flow b upward flow

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Takechi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (5)

[Claims] 1. A swirling flow type deep layer aeration tank using a microorganism-immobilized carrier, an air lift pipe having a bottom inclined toward the side of the aeration tank and an inflow port near the bottom of the bottom. And an air diffusion mechanism provided in the air lift pipe,
Device for treating wastewater using a fluidized bed type deep-layer aeration tank. 2. A swirling flow type deep layer aeration tank using a microorganism-immobilized carrier, wherein a bottom portion inclined toward a side portion of the aeration tank and an inflow port near the bottom of the bottom portion have an upper portion. Waste water using a fluidized bed deep layer aeration tank having an air lift pipe having an outflow port, an air diffusing mechanism provided in the air lift pipe, and an air diffusing mechanism separately provided on a side portion of the air lift pipe. Processing equipment. 3. The fluidized bed system deep layer aeration according to claim 1, wherein the bottom of the aeration tank is inclined downward from the downward flow in the aeration tank toward the upward flow direction. Wastewater treatment equipment using a tank. 4. The treatment of wastewater using the fluidized bed type deep layer aeration tank according to claim 1 or 2, wherein the bottom of the aeration tank is provided at a corner of the aeration tank. apparatus. 5. The bottom of the aeration tank is formed in a V shape, and the V
The wastewater treatment apparatus using the fluidized bed type deep layer aeration tank according to claim 1 or 2, wherein the groove portion of the mold is inclined downward toward the side portion of the aeration tank.