JPS6339317B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a purification device for closed water bodies that efficiently supplies and purifies air to closed water bodies such as lakes, reservoirs, and inner bays where eutrophication is progressing. .

[Conventional technology]

In recent years, eutrophication has progressed in closed water bodies such as lakes and inner bays due to the influx and accumulation of nutrients such as nitrogen and phosphorus from surrounding basins, which has become a social problem. For this reason, currently the method of regulating organic matter, nitrogen, and phosphorus in the inflow water of closed water bodies is being implemented as an effective means of preventing eutrophication.

[Problem that the invention seeks to solve]

However, because the full details of the eutrophication mechanism have not yet been elucidated and efficient purification methods have not been established, few attempts have been made to actively purify and regenerate closed water bodies such as lakes and marshes. The current situation is that there is no such thing.

The present invention was made in view of the current situation, and is an attempt to elucidate the entire mechanism of eutrophication, and from there, create a device for purifying and regenerating closed water bodies.

[Means for solving problems]

The present inventors first considered that the underlying mechanism of eutrophication proceeds as follows.

Lakes and marshes in Japan are classified as temperate lakes, and have two circulation periods throughout the year, in autumn and spring, and two stagnation periods in winter and summer. During the stagnation period, the lake is divided into a surface layer a, a thermocline layer b, and a lower layer c, as shown in Figure 2, and the state of the lake water changes vertically.

In other words, in the surface layer A, phytoplankton proliferates through photosynthesis using sunlight, and dissolved oxygen
DO becomes supersaturated. On the other hand, in the lower layer C, plankton that died in the surface layer A fall down and are oxidized and decomposed, so DO is consumed and the atmosphere often becomes anoxic. When this oxygen deficiency occurs, H ₂ S begins to be generated and iron, manganese, nitrogen, and phosphorus are eluted at the same time. When it becomes the next circulating group, the eluted nutrients will diffuse throughout the closed water area, promoting the progress of eutrophication.

Therefore, in order to break this vicious cycle of eutrophication, it is necessary to supply oxygen to the lake bed 101 and prevent the elution of nutrients and the like. Regarding the method of supplying oxygen to lakes, etc., the water depth of the lake, etc.
Depending on the progress of eutrophication, etc., the following two methods can be considered depending on the purpose and function.

Circulating aeration method destroys the stratification, so it is suitable for lakes and marshes where the water depth is relatively shallow and there is an extreme lack of dissolved oxygen. It is also effective in improving the water quality of water source ponds that are suffering from water with strange smells and tastes.

Deep aeration is a method that provides sufficient oxygen to deep water without destroying the stratification, and is effective in preventing the temperature of surface water from dropping in the summer and preventing the outflow of turbid water.

Among these, the present invention further improves the circulating aeration method and proposes an apparatus that performs two-stage aeration of the surface layer a and the lower layer c without destroying the thermocline layer b.

FIG. 1 shows the configuration of the present invention, which comprises an outer tube 1, an inner tube 2, an air chamber 3, a water seal tube 4,
It has a water supply device 5. Note that 100 indicates the water surface and 101 indicates the lake bottom.

The outer tube 1 is composed of the outer tube of a double tube, and the upper and lower ends are open, and the upper end side is floated on the water surface 100 side by a floating body etc., and the lower end side is moored to the lake bottom 100 side. It is installed vertically in the water.
This outer tube 1 serves as a passage for sending air bubbles and low layer water rising therein toward the surface layer a side. However, a water supply/drainage port 1a is provided in the middle, and if this is located below the cline b, part of the low-level water can be discharged from there, and on the other hand, water below the cline b can be sucked in. can.

The inner tube 2 is a tube inserted into the outer tube 1 of the double tube structure, and when inserted, a space for low water rise is formed between the inner tube 2 and the outer tube 1. The inner pipe 2 is closed at its upper end and opened at its lower end within an air chamber 3, which will be described later, and serves as a passageway for transporting surface water to the lower layer c side.

The air chamber 3 has its upper end fixed to the outer circumference of the outer tube 1,
It is provided so as to cover the lower side of the outer tube 1. This air chamber 3 is provided to store air between it and the lower part of the outer tube 1.

The water seal tube 4 is provided in the air chamber 3 so as to surround the lower end of the outer tube 1 by expanding the diameter of the lower end wall of the inner tube 2 and surrounding it upward. This water seal tube 4
has a structure in which the air chamber 3 and the outer circumference of the lower part of the outer tube 1 are partitioned while only the upper part communicates with each other, and an inverted U-shaped water seal path 4a is formed so that water can be easily sealed to prevent water from entering the outer tube 1. .

The water supply device 5 mixes surface water and air, sends the mixed water into the inner pipe 2, and blows it upward into the air chamber 3.

[Effect]

In the surface layer a of lakes and marshes, natural aeration occurs at the lake water surface 100 due to the influence of wind, etc., and there is also the influence of photosynthesis by algae, etc., so that dissolved oxygen in the surface layer water reaches nearly the saturation value. However, due to the heat from the sun, the temperature of the lake's water surface has risen to almost the same temperature as the average temperature.

This high-temperature dissolved oxygen-rich surface water is pumped up by the water supply device 5 (arrow A), air is sucked in (arrow B), mixed, and the mixed water is guided into the inner tube 2. At this time, some of the air dissolves due to the increase in water pressure, and the dissolved oxygen concentration in the mixed water further increases. The mixed water that has descended in the inner tube 2 as shown by the arrow C flows downward into the water seal tube 4 as shown by the arrow D. At this time, the mixed water rich in dissolved oxygen is mixed with the low layer water as shown by the arrow H, aerating the low layer water and raising the water temperature. On the other hand, since the flow rate of the mixed water flowing down the water seal tube 4 decreases as described above, the air that has not been completely dissolved in the mixed water and has become bubble-like is separated from the water flow. Then, as shown by the arrow, go up the inverted U-shaped water seal road 4a,
It accumulates in the upper part of the air chamber 3. When the air accumulated in the upper part of the air chamber 3 is conducted into the outer tube 1 through the inverted U-shaped water seal path 4a, the water seal is broken and becomes an inverted siphon shape, causing the air accumulated in The air becomes bullet-shaped bubbles and rises inside the outer tube 1 all at once. At this time, the water supply and drainage port 1a in the middle of the outer pipe 1 is connected to the cline b.
If it is installed so that it opens at the bottom, low-lying water is first sucked in as shown by the arrow ri by the rise of the cannonball-shaped air bubbles, and then passes through the same path as the air flow path mentioned above. As shown in Fig. 2, a part of the water is discharged from the water supply/drainage port 1a to the lower part of the cline b, and stirs the low water.

On the other hand, if the bullet-shaped air further rises as shown by arrow 1, it will suck in the water below the cline B as shown by arrow wo and discharge it to the surface layer a through arrow 1 (arrow wa). The bubble bullet that has reached the water surface 100 is destroyed on the water surface 100, causing ripples on the water surface 100 and spreading. At this time, the pumped up low-level water and the water below the cline b spreads along the water surface 100 along with ripples and mixes with the surface water while being aerated and diffuses. At the same time, a rise in water temperature can be suppressed by mixing low-temperature low-level water and water below the cline b.

In this way, the present invention provides water supply and drainage ports 1a to prevent destruction of the surface layer a and lower layer c without destroying the cline layer b.
The system is designed to simultaneously stir and aerate each of the two parts individually. That is, first, the lower layer C is aerated with surface water containing a large amount of dissolved oxygen, and the air sent to the lower layer C side along with the surface water is used to discharge part of the lower layer water to the lower part of the cline layer B, and then the remaining The water in the lower layer of the water and the water in the lower part of the cline B is pumped up to the surface layer a, and aeration is carried out.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

FIG. 3 shows an embodiment of the present invention, which is comprised of an outer tube 10, an inner tube 20, an air chamber 30, a water seal tube 40, and a water supply device 50.

The outer tube 10 is equipped with a float 12 at its upper portion, and its lower portion is engaged with an anchor 14 on a lake bed 101 by a chain 13 via an air chamber 30, which will be described later, so that the outer tube 10 is suspended vertically in the water. Further, the upper and lower ends of the outer tube 10 are open, and a water supply and drainage port 11 is further provided in the middle thereof, and by adjusting the length of the chain 13, the water supply and drainage port 11 is opened at the bottom of the cline b. There is. It should be noted that the above-mentioned method of vertically installing the outer tube 10 is only an example, and it goes without saying that other methods may be used for vertically installing the outer tube 10.

The inner tube 20 is inserted into the outer tube 10 and has its upper and lower ends protruding from the outer tube 10, with the upper end being closed and the lower end being open.

The air chamber 30 is open at the bottom and has an outer tube 1 on the bottom surface.
It is formed of a box-like body with a through hole 31,
The outer tube 10 is passed through the through hole 31, and the outer tube 1
The peripheral edge of the through hole 31 is fixed to the outer periphery of the through hole 31. By installing it in this way, the air chamber 30 is connected to the outer tube 1.
0 will cover the bottom side. Incidentally, as described above, the chain 13 is moored to the lower open periphery of the air chamber 30 and connected to the anchor 14.
In addition, in this embodiment, a bottom plate 32 is provided in the center below the inner tube 20 of the air chamber 30 in a direction perpendicular to the inner tube 20, and the bottom plate 32 is provided in the direction perpendicular to the inner tube 20 to direct the direction of the mixed water of surface water and bubbles flowing out from the inner tube 20. and at the same time assist in the separation of air bubbles. Furthermore, a water inlet/outlet 33 is opened between the lower open peripheral edge of the air chamber 30 and the peripheral edge of the bottom plate 32, allowing communication between the inside of the air chamber 30 and the lower layer c side.

The water seal tube 40 is inserted into the bottom plate 32 within the air chamber 30.
While expanding the diameter of the lower end wall of the inner tube 20 in parallel with the inner tube 20, the inner tube 20 is bent in the middle to extend upward between the inner wall of the air chamber 30 and the outer peripheral wall of the outer tube 10, and is provided so as to surround the lower end of the outer tube 10. It is something that was given. By installing in this manner, an inverted U-shaped water seal passage 41 is formed by partitioning between the inner wall of the air chamber 30 and the lower outer circumferential wall of the outer tube 10, resulting in a water seal structure.

The water supply device 50 includes a water suction pipe 51 having one end immersed in water on the surface layer a side, a low water head pump 52 communicating with the water suction pipe 51, and an ejector 53 communicating with the water suction pipe 51.
and a water supply pipe 54 that communicates with the inner pipe 20.The surface water pumped from the water suction pipe 51 by a pump 52 as shown by arrow A is passed through an ejector 5.
3, it has a function of sucking and mixing air as shown by arrow B, guiding this mixed water into the inner pipe 20 through the water pipe 54, and making it descend therein. The inventors investigated the bubble rising speed and obtained a measured value of 0.3 m/S. Therefore, the descending flow velocity in the inner pipe 20 is 0.3
I tried to keep it above m/S. In addition, energy saving is possible by using a low head pump for the pump 52, but in addition, instead of the pump 52 and the diector 53, (compressed) air is blown into the water pipe 54 by a blower or compressor. Also good.

According to the device as described above, surface water rich in dissolved oxygen can be sent to the lower layer c and aerated. Further, the air that has not been completely dissolved is separated from the water by the bottom plate 32 and becomes bubbles, which accumulate in the inverted U-shaped water seal passage 41. When a certain amount or more accumulates and conducts into the outer tube 10, the water seal breaks, forming an inverted siphon shape, and blows out into the outer tube 10 all at once in the form of bullet-shaped bubbles. As it rises, low-level water is sucked into the outer pipe 10, and part of it is sucked into the lower part of the cline b through the water supply and drainage port 11, and the remaining low-level water and the cline b, which is sucked in from the water supply and drainage port 11, is absorbed into the outer pipe 10.
Water from the lower part can be pumped up to the surface layer a.
Therefore, the lower layer C and the surface layer A can be simultaneously and individually stirred and aerated without destroying the cline layer B.

〔Effect of the invention〕

According to the purification device of the present invention as described above, surface water rich in dissolved oxygen is sent to the lower layer and mixed with the lower layer water and aerated by increasing the amount of dissolved oxygen due to the air supply by the water supply device and the increase in water pressure. In addition to eliminating the shortage, by providing an inverted U-shaped water seal that intermittently raises bullet-shaped bubbles, a portion of the low-level water rises to the lower part of the cline, and the remaining low-level water and the lower part of the cline are released. The sucked water can be made to rise to the surface layer and aerated above the water surface, so the lower layer and surface layer can be stirred and aerated separately at the same time without destroying the cline, which has the excellent effect of making it possible to maintain the ecology. have.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the configuration of the present invention, FIG. 2 is a schematic diagram showing the situation of a closed water area during the stagnation period, and FIG. 3 is an explanatory diagram showing an embodiment of the present invention. In the figure, 1 and 10 are outer tubes, 2 and 20 are inner tubes, 3,
30 is an air chamber, 4 and 40 are water seal tubes, 5 and 50 are water supply devices, 1a and 11 are water supply and drainage ports, 4a and 41 are inverted U-shaped water seals, 100 is a water surface, and 101 is a lake bottom.

Claims (1)

[Claims] 1. An outer pipe that is vertically placed underwater with its upper and lower ends open and has a water supply and drainage port in the middle, an inner pipe that is inserted into the outer pipe and has its upper end closed and its lower end open, and the lower side of the outer pipe. an air chamber that is provided to cover the outer tube and has its upper end fixed to the outer periphery of the outer tube, and a lower end wall of the inner tube is provided in the air chamber so as to enclose the lower end of the outer tube while increasing its diameter, It has a water seal pipe that forms an inverted U-shaped water seal path by partitioning between the air chamber and the outer periphery of the lower part of the outer pipe, and a water supply device that mixes surface water and air and transports the mixed water from above inside the inner pipe. A closed water purification device featuring: