JP3336326B2 - Aeration method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for spraying fine air bubbles for aeration into a downward circulating water basin near a water surface.
The present invention relates to an aeration method in which uniform aeration is performed in the entire tank to improve the oxygen dissolution rate.

[0002]

2. Description of the Related Art An aeration tank is generally used as a method for aerobically treating sewage and sewage. By the way, in the conventional aeration tank, as shown in FIG. 3, a diffuser tube 21 is installed at the bottom of the aeration tank 1, and high-pressure air is supplied from the ground side by a blower 22 or the like through a duct 23, and is introduced into the water. The buoyancy of the released bubbles generates a swirling flow (circulating water flow) in the tank, and aeration by the bubbles is performed.

[0003]

However, in the method of diffusing and aerating from the diffuser tube 21 installed at the bottom of the aeration tank 1, the air bubbles released into the water from the diffuser tube 21 have a floating force and circulation. Since the water floats on the upward flow in a relatively short time, the contact time with the sewage is short, and the oxygen dissolution rate is poor. In this case, it is well known that the smaller the bubble diameter released into water, the higher the oxygen dissolution rate. However, if the aeration amount is reduced or the diameter of the released air bubbles is reduced, the supply air pressure is reduced and clogging of the air diffusion holes of the air diffuser is likely to occur. There were inconveniences such as the difficulty of circulating water flow.

[0004] The present invention is, by ejecting fine bubbles for aeration in a downward circulating water basin water near performs uniform aeration throughout a tank, provides aeration method to improve the oxygen dissolution rate The purpose is to do.

[0005]

In order to achieve the above object, an aeration method according to the present invention uses a rough air provided at the bottom of an aeration tank.
A predetermined angle with respect to the water surface in the circulating water basin generated over the entire aeration tank by the bubble generation diffuser
By screw-type aerator installed as
The fine bubbles for aeration are jetted into the downward circulating water basin near the water surface, and are screwed by the screw of the screw type aerator.
The generated water flow was generated by a diffuser for generating coarse bubbles
The method is characterized in that the microbubbles are placed on the downward circulating water flow so as to merge with the circulating water flow and stay in the circulating water flow .

[0006]

[Operation] In the circulating water basin generated over the entire aeration tank, fine bubbles for aeration are jetted into a downward circulating water basin near the water surface, and the fine bubbles are put on the downward circulating water flow. By staying in the circulating water flow, uniform aeration can be performed throughout the tank, and the contact time between the fine bubbles and water can be maintained for a long time, and the oxygen dissolution rate can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The aeration method of the present invention will be described below based on an embodiment shown in the drawings. First, a reference example is shown in FIG. In the figure, reference numeral 1 denotes an aeration tank having a required volume, which is arranged in parallel as shown in the figure or independently.
A diffuser 2 for generating a swirling flow is installed on one side wall of the aeration tank 1 at the bottom of the tank. The air diffuser 2 includes an air diffuser 21 installed at the bottom of the tank, a pressure air source 22 such as a blower installed above the water surface, and a duct 23 connecting the blower and the air diffuser.

The air diffuser 21 is installed at a position where a swirling flow (circulating water flow) is generated throughout the tank by the buoyancy of bubbles released into the water, and sufficient air is supplied from the blower to generate the swirling flow. The diameter of the diffuser hole is determined so that air is blown out without clogging of the diffuser holes of the diffuser tube 21, and the diffuser hole diameter is generally coarse. Further, the air supply amount of the blower 22 has a capacity and a pressure so as to be large, and is supplied to the air diffuser tube 21 through the duct 23.

Due to the air diffuser 2, fine air bubbles are generated in the water flow area of the circulating water flow generated in the entire tank, for example, along the inner wall surface opposite to the air diffusion tube 21 side and near the water surface. The generator 3 is provided. The microbubbles supplied into the circulating water stream by the microbubble generator 3 are carried to the bottom of the tank by the water area, preferably near the water surface, riding on the circulating water stream, and further circulated in the tank to make contact with water. Keep the time long and try to dissolve the oxygen in the air along the way.

Therefore, the direction of the fine bubbles ejected into the water by the fine bubble generating device 3 is determined so that the fine bubbles can easily get on the downward flow of the circulating water flow.

The microbubble generator 3 is constructed by connecting a microbubble diffuser 31 via a suction pipe 33 to a blower 32 provided above the water surface as shown in FIG. 1 or a book shown in FIG. As in the embodiment of the invention, the screw type aeration device 4 which self-absorbs the atmosphere by the negative pressure generated in the water area of the screw tip by the rotation of the screw, is crushed by the vortex of the screw, and is jetted into the water. Etc. are adopted.

In the case of a blower / diffuser tube type,
1 is provided with a rotatable joint 34 at a part of the diffuser pipe 33 so that it cannot be cleaned or inspected when clogging occurs. As shown on the right, the air diffuser 31 can be moved above the water surface. The amount of air bubbles blown out into the water by the air diffuser 31 determines the capacity and the like of the blower 31 so that aeration suitable for sewage can be performed, and the air supply amount can be adjusted.

In the case of the screw type aerator 4 as shown in FIG. 2, a pedestal 5 is provided above the aeration tank 1, and the screw type aerator 4 is mounted on the pedestal 5 at a predetermined angle with respect to the water surface. When installed, the rotation of the screw 41
The generated water flow merges with the circulating water flow generated in the air diffuser 2 to improve the swirling flow velocity.

In the aeration apparatus configured as described above,
When the air diffuser 2 diffuses air into the tank bottom water, the bubbles rise by buoyancy. By performing this aeration continuously, the upward flow becomes a circulating water flow throughout the tank,
Aeration is performed to some extent even if the air bubbles are large. Since fine bubbles are ejected in the circulating water flow area, the fine bubbles are diffused throughout the tank on the circulating water flow, and the residence time of the bubbles in the water becomes longer, thereby increasing the contact time with the water. Thus, the dissolution rate of oxygen is improved.

[0015]

According to the present invention, at was generated throughout aeration tank circulating water in the basin, is ejected fine bubbles for aeration in a downward circulating water basin water near particular, screw
The water flow generated by the rotation of the
So that it merges with the circulating water flow to improve the swirl velocity
The fine bubbles into the downward circulating water flow and circulate
By staying in the ring water flow , uniform aeration can be performed throughout the tank, the contact time between the fine bubbles and water can be maintained for a long time, and the oxygen dissolution rate can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a reference example of an aeration apparatus.

FIG. 2 shows an example of an aeration apparatus for implementing the aeration method of the present invention .
FIG.

FIG. 3 is an explanatory diagram of a conventional aeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aeration tank 2 Air diffuser 21 Air diffuser 22 Blower 3 Fine bubble generator 31 Air diffuser 32 Blower 4 Screw type aerator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-91298 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C02F 3/14-3/26

Claims (1)

(57) [Claims] 1. A dispersion for generating coarse air bubbles disposed at the bottom of an aeration tank.
In the circulating water basin generated over the entire aeration tank by the aeration device , at a predetermined angle with respect to the water surface
By the attached screw type aeration device, fine bubbles for aeration are jetted into the downward circulating water basin near the water surface,
Water generated by screw of screw type aerator
The circulating water flow generated by the diffuser for generating coarse bubbles
An aeration method characterized in that fine air bubbles are placed in a downward circulating water flow and retained in the circulating water flow so as to be merged .