JP4856801B2 - Method for reducing or suppressing the growth of algae in eutrophied lakes and the like, and apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for reducing algae grown by eutrophication of the water in the lake to improve the water quality of the lake, or an apparatus used for carrying out this method. It is.
[0002]
[Prior art]
Recently, in lakes and marshes (in this specification, lakes include lakes, marshes, ponds, pools, etc.), floating algae such as epiphytic algae and blue-green algae breed and their water quality deteriorates. , Tourism, recreation, etc. are widely known, and in particular, water pollution due to the occurrence of blue sea urchin is a problem. The cause is that domestic wastewater containing a large amount of N and P flows into the lake and the water in the lake becomes eutrophic, and this eutrophication causes a dramatic increase in epiphytic algae such as filamentous algae and floating algae such as blue-green algae. This is because the lake ecosystem changes.
[0003]
Thus, as a method for improving the water quality of lakes and marshes, various methods have been proposed and put into practical use, but there are still few methods that have sufficiently satisfactory effects. .
[0004]
Therefore, the inventor of the present invention first suppresses the growth of algae due to eutrophication of lakes by shielding a part of the water surface of lakes and the like having a depth of 5 m or less to improve the water quality with a required shading rate. The present inventors have invented a method for improving water quality, and the patent application is pending by the present applicant. This prior invention is based on the viewpoint that the lake surface is shielded with a light-shielding member, thereby suppressing the photosynthesis of algae under the light-shielding member to suppress its growth, and the water depth is relatively shallow with a depth of 5 m or less. It was intended to apply to lakes.
[0005]
However, as a result of repeated research, floating algae such as sea cucumbers have propagated and floated up to a depth of about 5 to 6 m on the surface of the lake, regardless of the scale of the lake and its depth. Mixing with the lower layer water does not occur, the sunlight does not reach the lower layer water, so that the floating algae do not breed, and further, the surface layer water at a depth of 5 to 6 m moves by wind, Water hardly moves, and floating algae and plankton such as blue sea cucumber located under the light-shielding member lose their fertility due to their inhibition of activation, and they do not reproduce even if exposed to sunlight again and die. I knew that. Depending on the transparency of the water in the lake and the geographical environment of the place where the lake is located, floating algae such as blue seaweed may be prosperous even at a depth of 5 to 6 m or more, for example, about 10 m. Of course, it can be effectively applied even in such a place.
[0006]
[Problems to be solved by the invention]
Based on the above knowledge, the present invention provides a method for reducing or suppressing the growth of algae in eutrophied lakes and the like, regardless of the depth and size of the lakes, and an apparatus therefor, It is to be an issue.
[0007]
[Means for Solving the Problems]
Configuration of the present invention a method has been made for the purpose of solving the above problems, the water surface of the lake to be suppressed proliferation or algae reduce luxuriant algal eutrophication, in the center with the front and rear when viewed from the side The buoyant light-shielding member formed in the middle and high with a mountain-shaped inclined surface is lifted, and the water surface in the lake is shielded so as to have a required light-shielding rate, thereby inhibiting the photosynthesis of algae and reducing the algae. In addition, the structure of the apparatus for carrying out the above-described method is a buoyancy formed in a medium-high height having a mountain-shaped inclined surface toward the center from the front and back as viewed from the side. Multiple light shielding members individually or loosely connected to each other, or housed in a frame member to form an area where the required light shielding rate can be obtained, and floated on the surface of the lake Partial water surface of the lake It is characterized in that so as to shield the.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. Figure 1 is plan view of an example of a buoyancy-shielding member, FIG. 2 is a sectional view of the member of Figure 1, Figure 3 is a first example plan view of a light-shielding member used in the method of the invention, FIG 4 is 3 5 and 6 are plan views of a second example and a third example of the light shielding member, and FIGS. 7, 8, and 9 are plan views and examples of usage examples of the light shielding member of FIG. 10 is a view taken along the line AA in FIG. 9, FIG. 11 is a plan view of an example of using the light shielding member, FIG. 12 is a view taken along the arrow BB in FIG. 11, and FIG. FIG. 14 is a cross-sectional view of FIG. 13, FIG. 15 is a perspective view of a fourth example of the light shielding member used in the method of the present invention, and FIG. 16 is a hook-shaped light shielding member unit. FIG. 17 is a plan view showing a first example of the arrangement of the light shielding members in FIG. 16, FIG. 18 is a plan view showing a second example of the arrangement of the light shielding members in FIG. 16, and FIG. FIG. 20 is a diagram of the arrangement of the light shielding members in FIG. Plan view showing an example, FIG. 21 is a D-D sectional view taken along line of FIG 20.
[0009]
First, in FIGS. 1 to 6, 1 a to 1 d are buoyant light-shielding members formed into squares, rectangles, and hexagons as viewed from above, and here, as an example, by polyolefin-based plastics such as polyethylene and polypropylene, It is shaped to float on the water surface with hollow or air bubbles. The specific gravity in this case is desirably such that when the light shielding members 1a to 1d are floated on the water surface, the water line is approximately in the vicinity of the center of the height (thickness) of the float. This is because even if the light shielding members 1a to 1d are blown by a wave or wind, the light shielding members 1a to 1d are stably floated on the water surface without being inverted. The light shielding member 1b~1d used in the present invention method shown in FIGS. 3-6, by forming a center with its front and back convex h, naturally even when overlap of members mutually by ruffling and wind In addition to being able to recover, rainwater and sand are not accumulated on the top surface. For this reason, the hole 2 may be provided in the center of the member. The light-shielding members 1b to 1d in the present invention are formed of the same material as the light-shielding member, such as a wooden material and other fibers, or a hollow body, in addition to plastic molded products, and the material thereof is Is optional.
[0010]
As illustrated in FIG. 7, the light-shielding members 1b to 1d formed in this way are placed in an appropriate number on the left half side of the whole water surface WL in the lake L so that the left half side has a required light-shielding rate. And place them floating without connecting them individually. In the example of FIG. 7, the light shielding members 1b are floated on the water surface in a free state without being connected or constrained to each other. The light shielding member group moves in a generally assembled state, and the water on the surface layer where the aquatic floats also moves in the same direction as the light shielding member group due to the wind and water flow. Experiments have confirmed that the light blocking effect of surface water in which the sea urchins floating in the group 1b are floating is not substantially impaired.
[0011]
In the present invention, by arranging the light shielding member 1b in the manner shown in FIGS. 7 to 9, a part of the lake is shielded as illustrated in FIG. In the surface water Hw that is shielded from light in such a form, floating algae such as blue sea urchins are floating, but these algae decrease or die without being propagated by the light shielding, and the water quality of this part Can be improved. Then, the surface layer water Hw including the water under the light shielding member 1b is moved by wind and waves, and when the water and the like are floating in the water that has entered under the light shielding member 1b due to this movement, Similarly, the blue sea bream and the like are not able to photosynthesis and have reduced activity, and even when exposed to sunlight again, they are not activated and do not proliferate.
[0012]
FIGS. 8 to 10 show other examples in which the light shielding member 1b is arranged on the surface of the lake water. In FIGS. 8 to 10, numerals 3 and 4 indicate that the light shielding member 1b is on the lake water by wind or waves. It is an oil fence-like partition fence that restrains floating freely. In FIG. 8, it is arranged so as to divide the surface of the lake roughly in half, and in FIG. In addition, the partition fences 3 and 4 are anchored to the lake shore in order to maintain a substantially fixed position on the lake water, or anchors or weights are provided via a cable 5 having a sufficient length. Moored at 6.
[0013]
In the above example, the buoyant light-shielding member 1b or 1c , 1d can be covered on the surface of the lake, covering a part of the entire surface, and can float relatively freely within a certain range. The algae floating between 5 and 6m in depth from the surface of the surface water shielded by the light-shielding member is cut off, and the growth of the algae is thereby prevented. Can be significantly reduced and suppressed.
[0014]
The arrangement of the light-shielding members 1b to 1d capable of inhibiting the activation of the algae as described above and suppressing the proliferation action thereof is not limited to the arrangement as illustrated in FIGS. Since the arrangement form illustrated in FIG. 14 may be used, this will be described. In the example of FIGS. 11 to 14, the use of the previous example as well as the light shielding member 1b, which is the same when using the light-shielding member 1c, and 1d. Here, a large number of light shielding members 1b, that is, 64 sheets as shown in FIG. 13, are arranged and arranged inside the light shielding float frame F in which the float tube 7 is formed in a square shape. FIG. 11 shows an example in which 25 units of light shielding float frames F are arranged in a square shape.
[0015]
Since the arrangement example of FIG. 11 is suitable for forming a light-shielding portion on a part of the surface layer of a large-scale lake, it is useful when applied to the surface water shielding of a large lake with a large surface area. 11 to 14 , the same reference numerals as those in FIGS. 1 to 10 denote the same members or the same parts.
[0016]
In the present invention, as illustrated in FIGS. 11 to 14, as a particularly preferable light shielding member used to form a light shielding portion on a wide range of surface layers, although it is a part of the water surface in the lake, FIG. A large light shielding member 1e as exemplified in FIG. 16 is used. That is, the light-shielding member 1e has a cross-sectional outer shape that is a medium-high shape h like the light-shielding member 1b in FIG. 4, but the light-shielding member 1e is formed to be long in its cross-sectional shape.
[0017]
The long-type light shielding members 1e are arranged in parallel, and the adjacent light shielding members 1e are loosely coupled to each other by a coupling member 8 such as a coupling cord to form a bowl-shaped light shielding body Fp. However (see FIG. 16), with this light shield Fp as a unit, a plurality of light shields Fp are arranged on the surface of the lake in the form illustrated in FIGS. If the light shielding body Fp is provided in such an arrangement, the water surface of the lake can be shielded on a large scale, which is very efficient. 17 to 21, the same reference numerals as those in FIGS. 1 to 12 denote the same members or the same parts.
[0018]
In the above explanation, the surface of the surface layer where floating algae such as blue-green algae are floating and proliferating in the lake by using the light-shielding member 1b to 1e, or by mixing them together is optimal. Shading rate, that is, abnormalities due to eutrophication of lake algae such as sea cucumbers by shading so as to leave only the level necessary for the habitat of fish etc. without killing 100% of sea cucumbers A method for effectively suppressing proliferation is described.
[0019]
As described above, the present invention is about 5 to 6 m from the surface where floating algae such as sea lions float in the lake, or about 10 m in depth depending on the transparency of water and the geographical environment of the lake. By covering the surface of the surface of the depth with a light shielding member, the lake can be purified regardless of the depth and scale of the lake.
[0020]
【Effect of the invention】
The present invention is as described above, and a required number of buoyant light shielding members are floated on the surface of a lake where algae are abnormally breeding due to eutrophication, and a part of the water surface of the lake is appropriately shielded by a light shielding rate. As a result, the activity of floating algae such as blue-green algae floating in the shaded surface water is reduced or killed, so abnormal occurrence of floating algae such as blue-green algae due to lake eutrophication Can be effectively and efficiently suppressed without using any artificial energy, and the lake can be purified.
[Brief description of the drawings]
[1] One example plan view of the buoyancy-shielding member.
FIG. 2 is a cross-sectional view of the member of FIG.
FIG. 3 is a plan view of a first example of a light shielding member used in the method of the present invention .
4 is a cross-sectional view of the member of FIG.
FIG. 5 is a plan view of a second example of the light shielding member.
FIG. 6 is a plan view of a third example of the light shielding member.
7 is a plan view showing an example of use of the light shielding member of FIG. 3. FIG.
8 is a plan view showing an example of use of the light shielding member of FIG. 3. FIG.
9 is a plan view showing an example of use of the light shielding member of FIG. 3. FIG.
10 is a view taken along the line AA in FIG. 9;
[11] Rights elevational view of a usage example of the light shielding member.
12 is a view taken along the line BB in FIG.
13 is a plan view of the light shielding member unit of FIG. 11.
14 is a cross-sectional view of FIG.
FIG. 15 is a perspective view of a fourth example of a light shielding member used in the method of the present invention.
16 is a plan view of an example in which the light shielding member of FIG. 15 is formed in a bowl-shaped light shielding member unit.
17 is a plan view showing a first example of the arrangement of the light shielding members in FIG.
18 is a plan view showing a second example of the arrangement of the light shielding members in FIG. 16. FIG.
FIG. 19 is a view taken along the line CC in FIG.
FIG. 20 is a plan view showing a third example of the arrangement of the light shielding members in FIG.
FIG. 21 is a view taken along line DD in FIG.
[Explanation of symbols]
Lake L
1a to 1e Buoyant light-shielding member h Middle-high section 2 Hole 5 Rope 6 Anchor or weight 7 Frame

Claims (4)

A buoyant light-shielding member formed on the water surface of a lake that should reduce algae grown by eutrophication or to suppress the growth of algae, with a mountain-shaped inclined surface facing both sides from the side toward the center. Algae in a eutrophic lake characterized by floating and shielding the water surface in the lake to the required light shielding rate, thereby inhibiting photosynthesis of the algae and suppressing the reduction or growth of the algae To reduce or inhibit its growth. A plurality of buoyant light-shielding members formed in a mid-to-high shape having angled surfaces that are angled toward the center when viewed from the side are individually or loosely connected to each other, or housed in a frame member. Formed in an area where the required shading rate can be obtained, and floated on the water surface of the lake to partially shield the water surface of the lake. A device that suppresses proliferation.   The apparatus according to claim 2, wherein the light shielding member is a quadrangle or a hexagon when viewed from a plane.   The apparatus according to claim 2, wherein the light shielding member is formed to be long by extrusion molding of plastic.

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