JPH05146796A - Device for purifying closed natural water area - Google Patents

Abstract

PURPOSE:To improve water purification efficiency in the device for lakes and marshes by arranging a rotary aerator formed with a cylinder having an internal fixed spiral plate and the gas inlets arranged at the lower opening of the cylinder at intervals in a closed natural water area. CONSTITUTION:A rotary aerator 6 is formed with a tapered cylinder 60 wherein plural spiral plates 61 with the lead angle controlled to 0.7 to 1.3 and the air inlets 66 are arranged at the lower opening of the cylinder at regular interval and the aerator is set in a closed natural water area such as a lake 1. Air supplied from an air feed pipe 65 is supplied into the cylinder 60 from the air inlet 66. At this time, the air entraining the water in the lake is spiraled upward along the spiral plate 61. The air is micronized by the shearing force between the air and water to from fine bubbles which are discharged into the water in the lake from the upper part of the cylinder 60. The pressure drop is reduced, the bubble is micronized, and the purification efficiency is improved in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purification device for a closed natural water area such as a lake, a reservoir, a regulating pond or a dam, and more particularly to a closed natural water area which supplies fine bubbles of oxidizing gas to the water. The present invention relates to a closed natural water purification device equipped with an aerator capable of forming a strong and stable circulating flow in water.

[0002]

2. Description of the Related Art With the advancement of modern human lifestyles, eutrophication of natural waters such as lakes and marshes is contaminated and deteriorated. Therefore, various aeration methods have been adopted to purify such closed natural waters, and air bubbles are subdivided by pressurizing and ejecting air into the water from annular or plate-shaped aerator pores installed in water such as lakes and marshes. Supply method, a method in which air is introduced into a water flow in which a shearing force is formed by a rotating blade or a water discharge pipe to subdivide it, or a fountain method in which lake water or the like is pumped up and ejected upward on the spot, Furthermore, there is a method of generating convection in a water area such as a lake by intermittently ejecting air from an air pumping cylinder that is immersed in the lake water and hung vertically.

In these types of aeration, necessary adjustments are basically made depending on the amount of air fed and the number of aerators installed. However, in order to develop a highly functional closed natural water purification device for the purpose of energy-saving advanced lake water treatment, a large amount of fine oxidizing gas bubbles are generated, and further It is necessary to control the formation of the circulating flow containing it.

However, in the aeration of the above system, even if fine pores are provided in the diffuser pipe or the diffuser cylinder, for example, most of them eventually result from the surface tension of the bubbles when they are ejected from the pores. There are various drawbacks as described below, because the method is an air diffusion method by jetting or a method of generating bubbles by shearing the rotating blades and the projections. For example, in the method of ejecting air from a diffuser tube, diffuser plate, or cylinder, no matter how fine pores are provided, the surface tension of the bubbles when they eject from the pores results in about several millimeters. However, there is a drawback that large bubbles having a diameter of 10 are generated, and it is impossible to generate bubbles smaller than that. Further, there have been problems such as an increase in power cost and the occurrence of clogging due to the long-time operation.

Further, in the method utilizing the shearing force between the rotary blade and the projection, there is a problem that aquatic animals, microscopic organisms and the like are destroyed by the contact with the blade and the projection. In the aerator in the conventional closed natural water purification apparatus having the above-mentioned drawbacks and problems, the amount of fine bubbles generated is small, and it has been impossible to expect an increase in the amount of dissolved oxygen in lake water or the like. Further, since it is not possible to easily control the diameter and the generation amount of the fine bubbles and to form a strong and stable circulation flow, there is a problem that the purification treatment of lake water cannot be efficiently performed.

[0006]

Means and Actions for Solving the Problems As a result of intensive studies conducted by the present inventors to solve the above-mentioned problems of the prior art, it is possible to easily supply fine air bubbles to lake water or the like, and We have developed a closed natural water purification system equipped with an aerator that can generate a suitable circulating flow. That is, the present invention is a closed natural water purification apparatus as described below. The first invention is
A swirl type aerator composed of a cylindrical body having a spiral plate fixed to the inner wall and an air supply port arranged at a slight distance immediately below the lower opening of the cylindrical body is arranged at the bottom of the closed natural water area. A closed natural water purification apparatus according to a second aspect of the present invention, wherein the whole or upper portion of the cylindrical body is a gradually contracting cylindrical body. A third aspect of the present invention is the closed natural water purification device according to the first or second aspect, characterized in that the spiral plate is a multi-row spiral plate. A fourth invention is the wastewater treatment apparatus according to any one of the first to third inventions, wherein a swivel plate support column is provided on the central axis of the cylindrical body, and the fifth invention is the cylindrical body. The closed natural water purification apparatus according to any one of the first to fourth inventions, characterized in that the lower opening is reduced.
The invention of No. 1 is the closure according to any one of the first to fifth inventions, wherein the spiral plate fixed to the inner wall of the cylindrical body is a plurality of spiral plates, and the lead angle is 0.7 to 1.3. It is a natural water purification device.

In the above invention, firstly, according to the aerator of the present invention, the pressure loss is considerably smaller than that of the conventional jet type aerator, and the efficiency of bubble generation in the flowing drainage is dramatically improved. .. Secondly, according to the swirl type aerator of the present invention, the average diameter of the generated fine bubbles can be reduced to several hundreds of microns or less. Therefore, the contact area between the lake water and the like and the oxidizing gas bubbles is 10 to 100 times that of the conventional method, and the residence time is 10 to 10 times.
It can be increased to 0 times, and the amount of dissolved oxygen can be dramatically increased.

Thirdly, the adoption of the tapered cylinder increases the flow velocity of the ascending gas-liquid two-phase flow, so that a strong and stable circulating flow can be formed in the closed natural water area. Moreover, since there is no particular protrusion in the tapered cylinder, there is almost no pressure loss. Fourth, although the conventional method of performing aeration by the collision with the high-speed rotating blades or the protrusions has a problem of destroying microscopic organisms, such a problem hardly occurs according to the present invention. Fifth, since the opening in the lower part of the cylindrical body is reduced, the airlift effect due to the rise of gas is further improved, and the formation of a circulating flow in lakes and marshes prevents the sedimentation of medleys etc. Then, the purification process by aeration can be performed. Sixth, since the air mass blown out from the air supply pipe arranged below is atomized in the ascending and entraining process in the cylindrical body, the aerator is hardly clogged.

[0009]

EXAMPLES Some examples of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration explanatory diagram of an example in which a closed natural water purification apparatus including a swirl type aerator according to the present invention is applied to a lake. In the figure, 65 is a gas transfer pipe,
6 is a swivel aerator according to the present invention, 1 is lake water, 3
Is a blower or compressor. In the figure, the purifying gas is supplied into the closed natural water 1 water from the end of the gas transfer pipe 65 to the closed natural water via the swirl aerator 6. In the swirl type aerator 6, bubbles are subdivided in the ascending process of ascending gas and water in the closed natural water region due to the air lift effect accompanied by the ascending gas, and gas-liquid renewal is instantaneously performed. Furthermore, the gas-liquid mixed flow flows through the cylindrical body with the spiral plate inside to form a strong circulation flow in the water area.As a result, fine bubbles are transported to the deep part of the closed natural water area. The part can reach the lower opening of the swivel aerator. By repeating the above process repeatedly, the dissolved oxygen content of lake water etc. 1 is increased, and further the oxygen-free mass at the bottom is diffused to close lake water etc. contaminated by eutrophication etc. Purification and regeneration of natural waters will be achieved.

In the above-mentioned closed natural water purification apparatus, since the cylindrical body having a spiral plate fixed inside is used as an aerator as shown in FIG. 2 and subsequent figures, first of all, a large pressure loss as in the conventional method using an air diffuser is required. Due to the method that requires less energy and uses the shearing force to subdivide gas-liquid, rather than generating large-diameter bubbles as in the case of diffuser tubes, it is possible to compare bubbles with extremely small diameters. Two types of large diameter bubbles are generated. Therefore, the contact surface area between the bubbles and the lake water or the like increases, and the dissolution efficiency of the gas into the water is greatly improved. As a result, COD and BOD of the lake water and the like can be reduced with high efficiency.

FIG. 2 is a plan view showing the overall construction of an example in which the closed natural water purification apparatus of the present invention is applied to a water purification plant mixing pond. FIG. 2 shows a part of the water treatment plant mixing pond. In the pond, first, activated carbon powder or the like is mixed into the closed natural body water entering the purification water channel 2 from the water channel inlet 2'to obtain clean water. However, these settle down in the waterways and cause the increase in the required amount of activated carbon and the like. This is represented by a situation in which, for example, when closed natural water at a flow rate of 7 m / sec passes through a purification channel, almost all of the activated carbon mixed with a channel length of 70 m settles in the channel. At this time, the swing type aerator 6 according to the present invention
.. are installed in various places in the waterway 2 with an upward inclination, and if a purifying gas is supplied to this from the blower or the compressor 3 via the valve 4 .. The activated carbon powder can be transported up to and at the same time the activated carbon powder can be prevented from settling at the bottom of the corner of the waterway.

FIG. 3 is a partially cutaway perspective view of the cylindrical body portion of the swirl type aerator according to the closed natural water purification apparatus of the embodiment of the present invention. In FIG. 3, 60 is a (resin) cylindrical body,
61 ... Is a spiral plate, 62 is a spiral plate supporting column, and 63 is a gas-liquid introducing part with a lower opening reduced.

FIG. 4 is a partially cutaway perspective view of a swirl type aerator relating to a closed natural water purification apparatus according to an embodiment of the present invention, and FIGS. 5 (a) and 5 (b) are a plan view and a vertical sectional view. ..
Here, the gas (usually air) is supplied from the gas supply pipe 65, and is supplied from the air supply port 66 to the cylindrical body 60 of the swivel aerator attached to the support 64. The support 64, the gas introduction part 63, and the gas supply pipe 65 are
They are fixed by adhesion or welding with a strong adhesive or the like, and they are fixed and attached to the aerator attachment base 67 by the attachment U band 68. In the figure, when gas flows in the gas supply pipe 65 from the direction of the arrow, it becomes an air mass at the air supply port 66 and is discharged into the closed natural water body water. This air mass is introduced into the gas-liquid introducing portion 63 in the process of rising due to its buoyancy, and in the process of increasing the swirl while rising toward the spiral plate 61, ... It is refined by the shearing force that is formed. In this example, four spiral plates 61 ... Are attached at 90 ° intervals, and the lead angle β is 1.0. Usually, the lead angle β is preferably about 0.7 to 1.3. Then, the gas-liquid two-phase flow containing the generated fine bubbles further increases its rising speed in the gradually contracting cylindrical body 60 ′, continuously forming a strong and stable circulating flow in the closed natural water area, and its deep layer. Fine bubbles will be transported to the part.

FIG. 6 is a distribution diagram of bubble diameters, bubble generation rates, etc. of bubbles generated by the conventional single tube aeration type aerator and bubbles generated by the aerator of the embodiment. The measurement conditions in this case are as follows.

When the aerator according to the present invention is installed in a closed natural water area, it is preferable to dispose a large number of pieces in the water area. Particularly, for example, a group of 3 to 5 pieces is arranged at appropriate distance intervals. It is also preferable to arrange them at the bottom center and the right side of a lake or the like so as to generate a stable and strong circulating flow in the lake or the like.

[0016]

As described above in detail in the embodiments and the like, according to the present invention, many excellent effects as described below are exhibited. (1) According to the aerator of the present invention, the pressure loss is considerably smaller than that of the conventional jet aerator, and the bubble generation efficiency in the closed natural water body water is dramatically improved. (2) In the conventional ejection method, even if the diameter of the pores of the irregular porous tube made of ceramics or the like is reduced to about micron, the diameter of the bubbles generated therefrom is about several millimeters on average. According to the swirl type aerator of the present invention, the average diameter of the fine bubbles generated is from several 100 μm to several 10 μm.
Can be miniaturized. Therefore, the contact area between the lake water etc. and the bubbles of the oxidizing gas etc. can be extremely increased,
As a result, the amount of dissolved oxygen in lake water or the like can be dramatically increased. (3) By adopting the taper cylinder, the swirl rising velocity of the rising gas-liquid two-phase flow is increased, and a strong and stable circulating flow can be formed in the closed natural water area. At this time, there is almost no pressure loss in the tapered cylinder.

(4) In particular, in the case where the opening at the lower part of the cylindrical body is narrowed and reduced, in order to further improve the airlift effect due to the rise of gas, the sludge and the like that settle near the water bottom in the naturally closed water area are rolled up. , It is possible to prevent decay near the bottom of the water. (5) The conventional method of performing aeration by colliding with a high-speed rotating blade or a protrusion has a problem of destroying microscopic organisms, but according to the present invention, such a problem does not occur at all. (6) Since the air mass ejected from the air supply port of the swirl type aerator according to the present invention is atomized in the ascending and entraining process, there is almost no clogging in the aerator.

[Brief description of drawings]

FIG. 1 is an overall configuration explanatory diagram of an example in which a closed natural water purification device including a swirl aerator according to an embodiment of the present invention is applied to a lake.

FIG. 2 is an overall configuration explanatory plan view of an example in which a closed natural water area purification device including a swirl aerator according to the present invention is applied to a water purification plant mixing basin.

FIG. 3 is a partially cutaway perspective view of a cylindrical body portion of the swivel aerator of the embodiment.

FIG. 4 is a partially cut-away schematic mounting perspective view of the swivel aerator of the embodiment.

5 (a) and 5 (b) are a plan view and a vertical sectional view of a swivel aerator of an embodiment.

FIG. 6 is a distribution diagram of bubble diameters and bubble generation rates of bubbles generated by a conventional single tube aeration type aerator and a swirl type aerator according to an embodiment of the present invention.

[Explanation of symbols]

 1: Lake water etc. 2: Closed natural water purification channel 2 ': Channel inlet 3: Blower 4: Valve 6 ...: Swirling aerator 60: Cylindrical body 60': Reduced cylindrical body 61 ... Plate support column 63: Gas-liquid introduction part 64: Support 65: Gas supply pipe 66: Air supply port 67: Aerator mounting stand 68: U band for mounting

Claims (6)

[Claims] 1. A swirl type aerator comprising a cylindrical body having a spiral plate fixed to an inner wall thereof and a gas supply port arranged at a slight distance immediately below the lower opening of the cylindrical body to close a natural water area. A closed natural water area purification device characterized by being arranged at the bottom. 2. The closed natural water purification apparatus according to claim 1, wherein the whole or upper part of the cylindrical body is a gradually contracting cylindrical body. 3. The closed natural water purification apparatus according to claim 1, wherein the spiral plate has a multi-row structure. 4. The closed natural water purification apparatus according to claim 1, wherein a swivel plate support column is provided on a central axis of the cylindrical body. 5. The closed natural water purification apparatus according to claim 1, wherein the lower opening of the cylindrical body is reduced. 6. The closure according to claim 1, wherein there are a plurality of spiral plates fixed to the inner wall of the cylindrical body, and the lead angle is 0.7 to 1.3. Natural water purification equipment.