JPH07251197A - Method for preventing propagation of suspended algae of inlet water basin - Google Patents

Abstract

PURPOSE:To increase an influential range by circulation of water and to improve the efficiency of preventing propagation of suspended algae by installing an air diffusing member between the inlet water basin and main water basin of a lake or pond and exchanging the water mass in the inlet water basin with the water mass in the main water basin by the air diffused from the air diffusing member. CONSTITUTION:The air diffusing member 4 is installed at the bottom between the inlet water basin 2 and main water basin 3 of the lake or pond 1 to exchange the inlet water mass 6 of the inlet water basin 2 with the main water mass 7 of the main water basin 3 by the air diffused from the air diffusing member 4. The air is diffused between the inlet water mass 6 deteriorated in water quality and the main water mass 7 having good water quality fed from the air diffusing member 4 installed at the bottom of the lake or pond 1 to generate a first circulating flow 20 and second circulating flows 21, 22 respectively on the inlet water basin 2 side and the main water basin 3 side. The surface water 23 of the inlet water basin 2 is attracted by the second circulating flow 21 a the surface layer water 24 and lower layer water 25 of the main water basin 3 are attracted by the second circulating flow 22, by which both water are mixed in the first circulating flow 20. The mixed water 26 spreads successively in the form of the middle layer flow of the second circulating flow 21, 22. The inlet water mass 6 and the main water mass 7 are thus mixed and exchanged and the abnormal propagation of the algae is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the growth of floating algae that prevents abnormal growth of floating algae in the inlet waters of lakes and marshes.

[0002]

2. Description of the Related Art The inlet waters of lakes and marshes have to have good scenery because they are the bases for hydrophilic activities, but they tend to retain water more easily than the main waters, and the amount of nutrients flowing in from rivers can be reduced. When the amount is large, there is a problem that abnormal growth of floating algae occurs and water pollution is likely to occur. Therefore, in order to solve such problems, conventionally, (1) a method of circulating water by full-layer aeration in a shallow water area, or (2)
A method of circulating water by a plurality of pumps continuously arranged in water is used.

[0003]

However, in the method of (1), since the depth of water is shallow and no density flow occurs, the range of influence of water circulation is small, and the efficiency of preventing the growth of floating algae is poor. The method (1) has a problem that the cost is remarkably high because a continuous circulating flow of water is generated by a pump.

Therefore, an object of the present invention is to solve the problems of the conventional methods for preventing the growth of floating algae as described above, and to generate a density flow, which has a large influence range due to the circulation of water, and thus has an efficiency of preventing the growth of floating algae. It is an object of the present invention to provide a method for preventing the growth of floating algae that is good and at a significantly low cost.

[0005]

In order to achieve the above-mentioned object, the present invention provides a diffuser member between the inlet water area and the main water area of a lake. It is characterized in that the water mass in the inlet water area and the water mass in the main water area are exchanged by the air diffusion from the air diffusion member. According to the invention of claim 2, in the invention of claim 1, between the main water area and the diffuser member, a fence is provided in the upper part near the boundary between the water mass of the inlet water area and the water mass of the main water area. It is characterized by mixing surface water in the water area and lower water in the main water area. According to the invention of claim 3, in the invention of claim 1 or 2, the automatic water quality measuring device is installed in the inlet water area and the main water area, and the air diffusion control device is installed on the ground, and the water quality automatic measuring device is used for measurement. It is characterized in that water quality information is input to the air diffusion control device, and the air diffusion control device controls the air diffusion operation by the air diffusion member based on this water quality information.

[0006]

In the invention of claim 1 as described above, air is diffused from the diffusing member provided at the bottom of the lake to between the inlet water mass with poor water quality and the main water mass with good water quality The generated circulating flow draws the surface water of the Irie water area, the surface water of the main water area and the lower layer water, and mixes them, and then the mixed water becomes a middle layer flow of the circulation flow, and becomes the inlet water area and the main water area. Each of them spreads, whereby the inlet water mass with poor water quality and the main water mass with good water quality are mixed and exchanged. In the invention of claim 2, when the air is diffused by the diffusing member by the fence provided in the upper part near the boundary between the inlet water area and the main water area, the main circulation flow is generated by the invention of claim 1. The surface water in the water area is blocked by the fence, and only the surface water in the inlet water area and the lower surface water in the main water area are attracted to the circulation flow.The surface water in the inlet water area to be diluted is the lower surface water in the main water area. Efficiently mixed with. Further, in the invention of claim 3, when the automatic water quality measuring device in the inlet water region detects abnormal growth of floating algae, this growth information is input to the aeration control device and is output from the aeration control device based on this input information. Depending on the management information, the air diffuser diffuses air between the inlet water mass and the main water mass to generate a circulation flow, and this circulation flow causes surface water in the inlet water area and surface water in the main water area and lower water When the automatic water quality measurement device detects that the water quality of the inlet water mass in the inlet water area has been improved, the information is input to the air diffusion control device and the air diffusion member The aeration is stopped.

[0007]

In the first embodiment of the present invention shown in FIGS. 1 and 2, an aeration member 4 is installed at the bottom of the lake 1 including the dam lake, between the inlet water area 2 and the main water area 3, and By the air diffusion from the air member 4, the inlet water mass 6 in the inlet water area 2 and the main water mass 7 in the main water area 3 are exchanged. 8 and 9 are air supply control devices installed on the ground and air supply sources to the air diffusing member 4, and 11 and 12 are installed in the inlet water area 2 and the main water area 3 to automatically measure the first and second water quality. Each device is shown. And the first
2 Inlet water mass 6 and main water mass 7 from automatic water quality measuring devices 11 and 12
Water quality information is continuously input to the air diffusion control device 8 by the first and second lines 13 and 14 indicated by chain lines, and the management information output from the air diffusion control device 8 based on this input information is indicated by the dotted line. By the third line 16 shown, the air is supplied to the air supply source 9 to control its operation.
The water quality observation sensors of the water layers of different heights of the automatic water quality measuring devices 11 and 12 are shown.

In the above-mentioned structure, air is diffused from the diffusing member 4 provided at the bottom of the lake 1 between the inlet water mass 6 with poor water quality and the main water mass 7 with good water quality, and bubbles are generated by the air bubbles. The first circulation 20 and the second on the inlet side and the main side
Circulating flows 21 and 22 are generated. The second circulation flow 21 draws the surface water 23 of the inlet water area 2, and the second circulation flow 22 draws the surface water 24 and the lower water 25 of the main water area 3 to draw the first water.
After being mixed in the circulating stream 20, this mixed water 26 is the second circulating stream.
It becomes a midstream flow of 21 and 22 and spreads to the inlet water area 2 and the main water area 3, respectively, and as a result, the inlet water mass 6 with deteriorated water quality and the main water mass 7 with good water quality are mixed and exchanged. Abnormal growth of algae is prevented.

Further, in the above-mentioned one, when the first automatic water quality measuring device 11 in the inlet water area 2 senses an abnormal growth of floating algae, this growth information is inputted to the aeration control device 8 by the first line 13, The management information output from the air diffusion control device 8 based on this input information is input to the air supply source 9 by the third line 16 and, as described above, the inlet water mass 6 and the main water mass from the air diffusion member 4. Aeration between 7 and 1st and 2nd circulation flow
20, 21, 22 occur, and the second circulation flow 21 causes the inlet 2
Surface water 23 of the main water area 3 and the lower surface water 25 of the main water area 3 are attracted by the second circulation flow 22 and mixed in the first circulation flow 20. In this way, the first automatic water quality measuring device 11 When it detects that the water quality of the inlet water mass 6 in the inlet water area 2 has been improved, the information is input to the aeration control device 8 and the air supply source 9
The air supply to the air diffusing member 4 from is stopped.

FIG. 3 is a view of the Yabakei Dam in Kyushu using the above-mentioned device, which is an inlet with a length of about 300 m and the air diffuser 4 is supplied with an air supply source 9 consisting of a compressor with an air discharge rate of 500 l / min. The experimental results are shown, showing the changes with time of each chlorophyll concentration in the surface layer of the inlet water area after the operation of this device. In this figure, chlorophyll a, b, and c are the types of chlorophyll due to the pigment, T is the total amount thereof, the lower column of them is the change over time in their concentrations, and the double circles are the most effective in this experiment. The data are shown respectively. Looking at the chlorophyll concentration T in this drawing, for example,
The concentration was 6.5 μg / l just before the operation of the device, but after 4 hours it decreased to about half of that, 3.2 μg / l, but after that the concentration was slightly higher than this, which is The chlorophyll concentration 4 hours after the start of the experiment shows that the second circulating flow 21 generated by this device attracted floating algae in the surface layer of the inlet water area and lowered the concentration. The subsequent increase in chlorophyll concentration was the result of the floating algae once pushed into the deep layer returning to the surface layer as the agitation in the inlet water area progressed, and the concentration of floating algae in the inlet water area becoming uniform in the depth direction. Can be said to be
From these facts, it can be seen that, depending on the size of the inlet water area, this device can eliminate the high density of algae in the inlet water area at the level of several hours.

The second embodiment of the present invention shown in FIGS.
Since there are the same parts as those in the first embodiment, such parts are designated by the same reference numerals and the description thereof will be omitted, and different parts will be mainly described. In this embodiment, a fence 30 is provided near the boundary between the inlet water area 2 and the main water area 3 at a position about 40 m away from the diffuser member 4 in the second circulation flow 22. 6 has a frame body 32 on the bottom surface of which the float 31 is attached.
A sheet-shaped fence main body 33 is hung from the bottom, and an anchor 34 is attached to the lower end of the fence main body 33. With this configuration, when air is diffused by the air diffuser 4, the fence 30 blocks the recirculation of the surface water 24 in the main water area 3 of the second circulation flow 22 that occurs in the first embodiment. Only the surface water 23 of the second circulation flow 21 of the inlet water area 2 and the lower layer water 25 of the main water area 3 are attracted to the first circulation flow 20. Therefore, the surface water 23 of the inlet water area 2 to be diluted is the first circulation flow.
It will be efficiently mixed with the lower layer water 25 of the main water area 3 via 20. The fence main body 33 is preferably a vinyl sheet, but may be another one as long as it is not deteriorated by ultraviolet rays.

[0012]

The present invention is as described above. According to the invention of claim 1, an air diffuser is installed in the middle of the inlet water area and the main water area of the lake, and the air is diffused from the air diffuser member. Since the water mass in the inlet water area and the water mass in the main water area are exchanged, the effect of density flow is large and the influence range of the water circulation is large, the growth algae growth prevention efficiency is good, and the cost is significantly cheap. There is. According to the invention of claim 2, in the invention of claim 1, between the main water area and the diffuser member, a fence is provided in the upper part near the boundary between the water mass of the inlet water area and the water mass of the main water area. Since the surface water of the water area and the lower water of the main water area are mixed, there is an effect that the surface water of the inlet water area to be diluted and the lower water of the main water area are efficiently mixed. Claim 3
In the invention of claim 1 or 2, the automatic water quality measuring device is installed in the inlet water area and the main water area, and the air diffusion control device is installed on the ground to display the water quality information measured by the automatic water quality measuring device. Input to the air diffusion control device, the air diffusion control device controls the air diffusion amount by the air diffusion member based on this water quality information, so that it is not necessary to manually operate the air diffusion member,
Disperses the required amount of air to the planned position automatically all the time,
There is an effect that it is possible to reliably and efficiently prevent the growth of floating algae.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the same.

FIG. 3 is a drawing showing the result of an experiment according to the above.

FIG. 4 is a plan view of the second embodiment.

FIG. 5 is a vertical sectional front view of the same.

FIG. 6 is a perspective view of the above fence.

[Explanation of symbols]

 1 Lake 2 Inlet water area 3 Main water area 4 Aeration member 6 Inlet water mass 7 Main water mass 8 Aeration control device 9 Air supply source 11 1st water quality automatic measurement device 12 2nd water quality automatic measurement device 20 1st circulation flow 21st 2 Circulating flow 22 Second circulating flow 23 Surface water in the inlet water area 24 Surface water in the main water area 25 Lower water in the main water area 30 Fence

Claims (3)

[Claims] 1. A diffusing member is installed between the inlet water area and the main water area of a lake, and the water mass of the inlet water area and the water mass of the main water area are exchanged by the air diffusion from this diffusing member. And a method for preventing the growth of floating algae in an inlet water area. 2. A fence is provided between the main water area and the aeration member near the boundary between the water mass of the inlet water area and the water mass of the main water area, and the surface water of the inlet water area and the lower layer of the main water area are provided. The method for preventing the growth of floating algae in an inlet water area according to claim 1, wherein the method is mixed with water. 3. An automatic water quality measuring device is installed in an inlet water area and a main water area, an air diffusion control device is installed on the ground, and water quality information measured by the automatic water quality measurement device is input to the air diffusion control device, The method for preventing proliferation of floating algae in an inlet water area according to claim 1 or 2, wherein the air diffusion control device controls the air diffusion operation by the air diffusion member based on the water quality information.