JP3758099B2 - Water purification levee - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water purification bank constructed so as to surround a desired purification water area.
[0002]
[Prior art]
In order to secure a hydrophilic space rich in amenities at the waterfront, it is essential to purify the water quality and form a good water environment.
[0003]
As such a water purification means, a so-called water purification bank is drawing attention.
[0004]
As shown in FIG. 4, the water purification dam 1 is a structure in which levee body materials 2 made of gravel and crushed stone are stacked in a trapezoidal shape from the sea bottom 3 and covered with a predetermined covering stone 4. If it is constructed so as to surround a predetermined water area, the seawater in the outer water area 5 is purified by the water purification dam 1 and flows into the inner water area 6.
[0005]
That is, when the seawater in the outer water area moves to the inner water area 6 due to the tides and the action of waves, the seawater passes through the gap between the dam body materials 2 of the water purification dam 1 and is included in the seawater at that time. Contaminated components such as plankton are attached or captured by a biofilm composed of a microorganism group attached to the surface of the levee body material 2, and are further ingested and removed by shellfish and crustaceans living between gravel.
[0006]
Thus, it has been found that the water purification bank 1 is a coastal structure that can create an inner water area with a clean water quality by the water purification function of the natural ecosystem.
[0007]
[Problems to be solved by the invention]
However, in water areas where water purification is required, eutrophication of the water quality is progressing, and dissolved oxygen is consumed by the elution load from sediment sludge in the vicinity of the sea bottom, and is often hypoxic. This tendency is particularly noticeable in summer when the water temperature rises and the amount of solar radiation increases.
[0008]
Therefore, if the oxygen-poor water near the seabed 3 passes through the water purification levee 1 and flows into the internal water area 6, the dissolved oxygen concentration in the internal water area 6 decreases, adversely affecting the survival of benthic organisms, and water purification. When passing through the bank 1, there was a problem that the seawater purification function of the bank was also reduced.
[0009]
Such a problem can be solved by installing a breaker structure in the water purification dam 1 and opening and closing the breaker structure according to the season, etc. Cause problems.
[0010]
The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a water purification levee that can prevent the inflow of poor oxygen water in an outside water area at a relatively low cost.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a water purification levee according to the present invention is a water purification levee obtained by stacking a predetermined levee body material in a substantially trapezoidal shape, as defined in claim 1. The permeable wall material is composed of a hardly permeable body material up to the height, and the permeable dam body material is formed upward from the height to form a permeable layer. A water-permeable wall material is stacked from the bottom to form an inflow blocking layer.
[0014]
In the water purification levee according to the present invention, the water near the bottom of the water is blocked by the impermeable layer built on the bottom of the water and hardly flows into the inner water area, but the water near the water surface is constructed on the impermeable layer. It flows into the inner water area through the permeable layer. That is, the poor oxygen water with a low dissolved oxygen concentration hardly flows into the inner water area, and only the water with a high dissolved oxygen concentration flows into the inner water area after being purified by the levee material of the permeable layer.
[0015]
Here, when the poorly permeable embankment material is piled up from the bottom of the water at the position adjacent to the hardly permeable layer to form an inflow blocking layer, the inflow of the poor oxygen water into the inner water area can be almost completely blocked.
[0016]
Further, in the water purification levee according to the present invention, the water near the bottom of the water is blocked by the impermeable layer built at the bottom of the water and blocked from flowing into the inner water area, and the water near the water surface is above the impermeable layer. It flows into the inner waters through the permeable layer constructed in That is, the poor oxygen water with a low dissolved oxygen concentration does not flow into the inner water area, and only the water with a high dissolved oxygen concentration flows into the inner water area after being purified by the levee material of the permeable layer.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a water purification bank according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.
[0018]
(First embodiment)
FIG. 1 is a cross-sectional view illustrating a water purification bank 11 according to the present embodiment. As can be seen from the figure, the water purification dam 11 of the present embodiment is configured by stacking predetermined levee body materials in a substantially trapezoidal shape, similar to the conventional water purification dam 1, but in this embodiment, The range up to a predetermined height (the range indicated by the arrow in the figure) is composed of a non-permeable levee body material 12 to form a non-permeable layer, and the upper portion from the height is configured with a permeable levee body material 13 to transmit water. Layers are formed and coated with a covering stone 4.
[0019]
As the poorly permeable bank body material 12, it is preferable to use crushed stone or gravel having a particle size of several centimeters. Moreover, as the water-permeable bank body material 13, it is good to use the thing with which a biological film adheres and organisms, such as a shellfish, can inhabit, for example, gravel and crushed stones with a particle size of about 20 cm to 30 cm.
[0020]
In addition, about the height of the poorly permeable layer comprised with the bank body material 12, what is necessary is just to determine how the dissolved oxygen concentration of seawater changes to an orthogonal | vertical direction in an external water area, and to determine suitably according to this investigation. However, for example, as shown in the figure, if it is set around 1 m below the water level 14 at low tide, the seawater in the outer water area 5 is purified by the permeable layer even at low tide. It can flow into the water area 6.
[0021]
If the water purification dam 11 is arranged so as to surround a predetermined sea area, the seawater in the outer water area 5 passes through the gap between the dam body members 13 constituting the permeable layer when tides and waves occur. Then, the seawater moves to the inner water area 6, and the contaminated components are removed by the biofilm composed of a microorganism group attached to the surface of the levee body material 13 while moving through the gap, so that the seawater becomes clean seawater.
[0022]
On the other hand, the water in the vicinity of the sea bottom 3 in the outer water area 5 is blocked by the hardly permeable layer formed of the dam body material 12 and hardly flows into the inner water area 6. That is, the poor oxygen water having a low dissolved oxygen concentration hardly flows into the inner water region 6, and only the water having a higher dissolved oxygen concentration is purified by the levee body material 13 constituting the permeable layer and then enters the inner water region 6. Inflow.
[0023]
As described above, according to the water purification levee according to the present embodiment, the poorly permeable layer is installed on the seabed, and the permeable layer is constructed thereon. Almost no water is allowed to flow into the water area, and only water having a high dissolved oxygen concentration can be purified by the levee material of the permeable layer and then flowed into the inner water area.
[0024]
Therefore, even in a water area where the eutrophication of water quality is progressing, there is no possibility that the anoxic water in which dissolved oxygen is consumed flows into the inner water area and adversely affects the ecology of the water area. Moreover, such a water purification levee can be constructed at a much lower cost than constructing a barrier structure with a concrete plate or the like because it only stacks two kinds of levee body materials having different particle sizes.
[0025]
In the present embodiment, crushed stones and gravel having a particle diameter of several centimeters are used as the hardly permeable embankment material. However, instead of these, construction by-products such as concrete waste and earth and sand may be used. Moreover, although the gravel and the crushed stone with a particle size of about 20 cm were used as a water-permeable embankment material, it may replace with these and a concrete waste material etc. may be utilized.
[0026]
(Second Embodiment)
Next, a second embodiment will be described. Note that components that are substantially the same as those of the conventional technology or the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0027]
Fig.2 (a) is sectional drawing which showed the water quality purification bank 21 based on this embodiment. As can be seen in the figure, the water purification dam 21 of the present embodiment is also composed of a non-permeable levee body material 12 in the range from the sea bottom to a predetermined height (range of the arrow in the figure), like the water purification dam 11 described above. In this embodiment, the permeable body is made of a hardly permeable layer, and the permeable wall member 13 is formed from the above-mentioned height to form a permeable body material 13 and is covered with the covering stone 4. An inflow blocking layer is constructed in which a hardly permeable bank body material 24 is piled up from the seabed and covered with sand 22 at a position adjacent to the outer water region 5 side of the hardly permeable layer made of the material 12.
[0028]
The dam body material 24 is preferably made of crushed stone or gravel having a particle diameter of about several centimeters, like the dam body material 12. A dike 23 constructed of crushed stone or the like is installed at the tip of the inflow blocking layer composed of the dam body material 24 so as to prevent the levee body material 24 and the sand 22 from flowing out. .
[0029]
In the water purification levee of the present embodiment, as in the first embodiment, the poor oxygen water having a low dissolved oxygen concentration does not flow into the inner water region 6 due to the action of the poorly permeable layer composed of the dam body material 12, Only water with a high dissolved oxygen concentration is purified by the permeable body material 13 of the permeable layer and flows into the inner water region 6. In the present embodiment, an inflow blocking layer composed of the hardly permeable dam body material 24 is further provided. Since it is installed, it becomes possible to almost completely prevent the inflow of the oxygen-poor water.
[0030]
In the present embodiment, the non-permeable levee body material 24 is covered with sand 22 to form an inflow prevention layer. However, if a sufficient inflow prevention effect can be expected only by the dam body material 24, it is necessary to cover the sand. Absent.
[0031]
Moreover, in this embodiment, although the inflow prevention layer was constructed | assembled in the outer water area 5 side, you may make it construct in the inner water area side instead of this or in addition to this.
[0032]
FIG. 2 (b) shows a modification in which such an inflow blocking layer is constructed on the inner water area side. That is, similarly to the water purification dam 11, the water purification dam 31 according to the figure is composed of a non-permeable levee body material 12 in the range from the sea bottom 3 to a predetermined height (the range of the arrow in the figure). In addition, the permeable body material 13 is formed upward from the height to form a water permeable layer, and these are covered with the covering stone 4, but in the present embodiment, the levee body material 12 is further formed. An inflow blocking layer in which the hardly permeable bank body material 25 is piled up from the sea bottom is constructed at an adjacent position on the inner water area 6 side of the hardly permeable layer.
[0033]
The dam body material 25 is also preferably made of crushed stone or gravel having a particle size of about several centimeters, like the dam body material 12 and the dam body material 24.
[0034]
Also in the water purification dam 31 according to this modification, as in the above-described embodiment, the inner water area 6 is brought about by the action of the poorly permeable layer constituted by the levee body material 12 and the inflow blocking layer also constituted by the dam body material 25. It is possible to allow only the water having a high dissolved oxygen concentration to be purified by the levee body material 13 of the permeable layer and then flow into the inner water area 6 while almost completely preventing the inflow of the poor oxygen water.
[0035]
(Third embodiment)
Next, a third embodiment will be described. Note that components that are substantially the same as those of the conventional technology or the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0036]
FIG. 3 is a cross-sectional view showing the water purification bank 41 according to the present embodiment. As can be seen from the figure, the water purification dam 41 of the present embodiment has a concrete box 42 as a water shielding layer installed on the seabed 3, and the water-permeable dam member 13 is substantially placed on the concrete box 42. The trapezoidal shape is used to form a water permeable layer, which is covered with a covering stone 4.
[0037]
The height of the concrete box 42 (arrow in the figure) may be determined as appropriate by investigating how the dissolved oxygen concentration of seawater changes in the vertical direction in the outside water area. As shown in the figure, if it is set near 1m lower than the water level 14 at low tide, it will flow into the inner water area 6 after purifying the seawater in the outer water area 5 with a permeable layer even at low tide. Can be made.
[0038]
Also in the water purification levee 41, water near the sea surface with a high dissolved oxygen concentration receives the water purification action of the dam body material 13 and flows from the outer water area 5 into the inner water area 6, while the water near the sea bottom with a low dissolved oxygen concentration. The water is almost completely blocked by the concrete box 42 and does not flow into the inner water area 6.
[0039]
Therefore, even in a water area where eutrophication of the water quality is progressing, there is almost no possibility that the anoxic water in which dissolved oxygen is consumed flows into the inner water area and adversely affects the ecology of the water area.
[0040]
【The invention's effect】
As described above, the water purification levee according to the present invention can prevent the inflow of poor oxygen water in the outside water area at a relatively low cost as described in claim 1, and has a hardly permeable levee body material. Since the inflow prevention layer constituted by is installed, the inflow of the poor oxygen water can be almost completely prevented.
[0042]
[Brief description of the drawings]
FIG. 1 is a sectional view of a water purification bank according to a first embodiment.
FIG. 2 is a cross-sectional view of a water purification bank according to another embodiment, (a) is a diagram according to the second embodiment, and (b) is a diagram according to a modification thereof.
FIG. 3 is a sectional view of a water purification bank according to a third embodiment.
FIG. 4 is a cross-sectional view of a water purification bank according to the prior art.
[Explanation of symbols]
11, 21, 31, 41 Water purification levee 12, 24, 25 Water-permeable embankment material 13 Water-permeable embankment material 42 Concrete box (water-impervious layer)

Claims (1)

In the water purification levee where a given levee body material is stacked in a trapezoidal shape,
Among the levee body materials, the water from the bottom to a predetermined height is made of a non-permeable levee body material to form a hardly permeable layer, and the upper part from the height is made of a permeable levee body material to make a permeable layer. A water purification levee characterized in that a non-permeable levee body material is stacked from the bottom of the water at a position adjacent to the non-permeable layer to form an inflow blocking layer.

Images