JPH07988A - Wastewater treatment equipment - Google Patents

Abstract

PURPOSE:To increase the amt. of a microorganism to be retained by increasing the amt. of dissolved oxygen and decreasing the lifting speed of a carrier. CONSTITUTION:A reaction tank 1 is filled with waste water and a carrier, a bubble is formed by an air blowing device 10, a microorganism is immobilized on the carrier entrained by the bubble and circulated, org. compds. are decomposed by the biological membrane, and the microorganism is released from the carrier in this waste water treating device. The air blowing device 10 consists of a rotary cylinder 11 supported freely rotatably by an air feed pipe 13, a motor 16 for rotaing the cylinder 11, plural nozzles 17 furnished to the cylinder 11 and a air impingment baffle plate 18 opposed to the nozzle 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment apparatus for biologically treating industrial wastewater, sewage and domestic wastewater containing various organic compounds.

[0002]

2. Description of the Related Art Conventionally, as a method for treating wastewater by utilizing microorganisms, an activated sludge method in which a mixed solution of wastewater and activated sludge is aerated in a biological reaction tank and then activated sludge and supernatant water are separated in a sedimentation tank For the purpose of performing highly efficient wastewater treatment,
A biofilm method has been developed in which a microorganism is attached to a carrier that is circulated along with air bubbles, an organic compound is decomposed by the microbial film, and then the microorganism is separated from the carrier.

FIG. 3 shows a conventional wastewater treatment apparatus using the biofilm method.
Will be described. An air lift pipe 2 is provided in the reaction tank 1, a stirring blade 4 rotated by a motor 3 is arranged so as to face the upper part of the air lift pipe 2, and an air lift pipe is arranged so as to face the lower part of the air lift pipe 2. A blowing device 5 is provided. Further, an inverted cone-shaped air separating member 6 is provided above the reaction tank 1, and a precipitation tank 7 is formed on the outer periphery of the air separating member 6.

The reaction tank 1 is filled with waste water to be treated and a carrier, and when air is blown by the air blowing device 5, bubbles due to the air adhere to the carrier, and the carrier has an air lift pipe 2 due to the buoyancy of the bubbles. Rises to the upper part of the reaction tank 1 through the inside of the chamber and collides with the air separation member 6, air bubbles are separated from the carrier, the carrier descends in the reaction tank 1 through the outer periphery of the air lift pipe 2, and in this order. The carrier is circulated. When the microorganisms gradually adhere to the carrier with the lapse of time and the microbial membrane expands while decomposing the organic compounds, the apparent specific gravity becomes lighter and the microorganisms are more likely to float. At this time,
When the stirring blade 4 is rotated, the microorganisms are separated from the carrier,
Microorganisms are accumulated in the settling tank 7, and the treated water is discharged from the drainage port 8.

[0005]

By the way, in the above-mentioned wastewater treatment apparatus, it is necessary to increase the amount of dissolved oxygen in the reaction tank 1 in order to increase the amount of microorganisms retained, and for that purpose, the air blowing device 5 is used. It is conceivable to increase the amount of air blown by the air, or to blow in a gas with a high oxygen content, but the use of high-concentration oxygen is problematic in terms of cost. There is a problem that stable operation cannot be performed because the rising speed becomes faster and the amount of microorganisms retained decreases, the interface between the carrier and air separation part rises, and the carrier flows out into the treated water. There is.

[0006] On the other hand, as a technique for refining bubbles with a constant amount of air to increase the amount of dissolved oxygen, Japanese Patent Laid-Open No. 3-2296
According to Japanese Patent No. 96, the bubbles generated by the bubble generator are
A method of miniaturizing by the shearing action of a rotating impeller is known, but when this is adopted in the above-mentioned wastewater treatment device, since the drive part is immersed in the liquid, the volume loss in the reaction tank is reduced. With the problem of being big,
Since the shearing action of the bubbles is weak and the fine effect of the bubbles is small, there is a problem that the buoyancy of the bubbles is large and the ascending speed of the carrier attached to the bubbles is high, and the amount of microorganisms retained is reduced.

The present invention is intended to solve the above problems, and enables bubbles to be efficiently miniaturized with a simple structure,
An object of the present invention is to provide a wastewater treatment apparatus capable of increasing the amount of microorganisms retained by increasing the dissolved oxygen amount and slowing the carrier rising speed.

[0008]

To that end, in the wastewater treatment apparatus of the present invention, the wastewater and the carrier are filled in the reaction tank 1, bubbles are formed by the air blowing device 10, and the bubbles are circulated along with the bubbles. In a wastewater treatment device in which microorganisms are attached to a carrier, an organic compound is decomposed by the biofilm, and the microorganisms are separated from the carrier, the air blowing device 10 includes an air supply pipe 13
And a rotary cylinder 11 rotatably supported by the rotary cylinder 11.
It is characterized by comprising a drive motor 16 for rotating the rotary cylinder 11, a plurality of nozzles 17 formed in the rotary cylinder 11, and air collision members 18 and 19 arranged so as to face each nozzle 17. It should be noted that the numbers added to the above-mentioned configurations are for comparison with the drawings in order to facilitate the understanding of the present invention, and the configurations of the present invention are not limited thereby.

[0009]

In the present invention, when the rotary cylinder is rotated during the blowing of air, the air blows out as bubbles while being imparted with a rotational force from each nozzle, and then collides with the air collision member and is disturbed. A flow is formed, and the bubbles are successively sheared by the rotating air impingement member, so atomization of the bubbles is efficiently promoted.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 shows an embodiment of a wastewater treatment apparatus of the present invention, FIG. 1 (A) is a partial vertical sectional view, and FIG. 1 (B) is FIG.
It is a top view of (A). It should be noted that this embodiment is applied to the air blowing device of the wastewater treatment device described in FIG.

An air blowing device 10 according to the present invention is arranged below the reaction tank 1. The air blowing device 10 includes a rotating cylinder 11 and a bearing 12 that rotatably supports the rotating cylinder 11.
An air supply pipe 13 connected to the bearing 12 for supplying air into the rotary cylinder 11, a driven gear 14 fixed to the rotary cylinder 11, and a drive gear 15 meshing with the driven gear 14.
And a drive motor 16 for rotating the drive gear 15. A plurality of nozzles 17 are formed on the upper part of the rotary cylinder 11, and the air collision members 18, 18, ... Composed of L-shaped plate members facing the nozzles 17, 17 ,. Is arranged on the outer periphery of the.

The operation of the present invention having the above structure will be described. Waste water to be treated and a carrier are filled in the reaction tank 1, and when air is blown by the air blowing device 10, bubbles due to the air adhere to the carrier, and the carrier rises to the upper part of the reaction tank 1 due to the buoyancy of the bubbles. To do. Subsequent operations are the same as those described with reference to FIG. In the present invention,
At the time of blowing air, the rotary cylinder 11 is rotated. The air blows out as bubbles while being given a rotational force from the nozzle 17, and then collides with the air collision member 18 to form a turbulent flow, and the bubbles are sheared one after another by the rotating air collision member 18. The atomization of bubbles is efficiently promoted.
Therefore, the amount of microorganisms retained can be increased by increasing the dissolved oxygen amount and decreasing the carrier rising speed.

FIG. 2 is a partial vertical sectional view showing another embodiment of the wastewater treatment apparatus of the present invention. The same components as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, the air collision member 19 is composed of a tubular mesh member. The air is ejected while being given a rotational force from the nozzle 17, and then the air collision member 19
Since the bubbles collide with each other and are successively sheared by the rotating mesh member, atomization of the bubbles is efficiently promoted.

The present invention is not limited to the above embodiments, and various modifications can be made by those having ordinary knowledge in the technical field to which the present invention belongs. For example, as a method of rotating the rotary cylinder 11, a well-known method other than gear transmission can be adopted, and various methods can be adopted as a method of connecting the rotary cylinder 11 and the air supply pipe 13.

[0015]

As is apparent from the above description, according to the present invention, it is possible to efficiently miniaturize bubbles with a simple structure, increase the amount of dissolved oxygen, and slow the rising speed of the carrier. The amount of microorganisms retained can be increased.

[Brief description of drawings]

1 shows an embodiment of a wastewater treatment apparatus of the present invention, and FIG.
1A is a partially vertical cross-sectional view, and FIG. 1B is a plan view of FIG.

FIG. 2 is a partial vertical sectional view showing another embodiment of the wastewater treatment apparatus of the present invention.

FIG. 3 is a schematic cross-sectional view showing a conventional wastewater treatment device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reaction tank, 10 ... Air blowing device, 11 ... Rotating cylinder, 1
2 ... Bearing 13 ... Air supply pipe, 16 ... Drive motor, 17 ... Nozzle 18, 19 ... Air collision member

Claims (1)

[Claims] 1. A reaction tank is filled with waste water and a carrier, bubbles are formed by an air blowing device, microorganisms are attached to the carrier circulated along with the bubbles, and organic compounds are decomposed by the biofilm. In the wastewater treatment device for separating microorganisms from a carrier, the air blowing device is formed in the rotary cylinder, a rotary cylinder rotatably supported by an air supply pipe, a drive motor for rotating the rotary cylinder, and the rotary cylinder. Multiple nozzles,
A wastewater treatment device comprising an air collision member arranged so as to face each nozzle.