JP2002136993A - Water area cleaning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep good water quality environment by improving the pollution of water back water area extending between an artificial island and a coast area. SOLUTION: In the water area cleaning system, underwater structures 6, 6 are constructed along the boundary of the back water area 4 extending between the artificial island 2 and the coast area 3 and the outer water area 5 connected to the back water area, and a water channel 7 allowing the back water area 4 to communicate with the outer water area 5 is provided to the artificial island. A gate 8 constituted so as to be opened only when the water level of the outer water area 5 is less than that of the back water area 4 is disposed on the side of the back water area 4 of the water channel 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification system mainly installed in a water area extending between an artificial island and a coast.

[0002]

2. Description of the Related Art It has been a practice to construct an artificial island by reclaiming offshore and use the artificial island as a factory site, but recently it has been increasingly used as a marine airport.

[0003] When an artificial island is constructed offshore in this way,
Naturally, in the water area extending between the artificial island and the coastal area, that is, in the backwater area, seawater exchange becomes difficult to be performed as compared with the case where there is no artificial island, and the seawater stagnates.

As a result, pollutants in the water settle down, the organic matter content in the sediment increases, the elution of nutrients into the seawater and the internal load increase, and eutrophication produces a large amount of phytoplankton. This causes the dead body to settle, which also causes an increase in the organic matter content in the sediment.

[0005] A vicious cycle in which water pollution is further promoted due to such an increase in internal load is repeated, and a large amount of oxygen is consumed due to decomposition of organic substances near the bottom layer, thereby causing death of aquatic organisms. Connect.

[0006]

As described above, the stagnation of seawater in the water area behind causes water pollution in the water area. For this reason, technology development that can preserve the water quality environment has been awaited, but it is difficult to carry out water quality conservation in the above-mentioned situation, and no effective measures can be taken at present.

[0007] The present invention has been made in view of the above-mentioned circumstances, and provides a water purification system capable of improving water pollution in a backwater area extending between an artificial island and a coastal area and maintaining a favorable water quality environment. The purpose is to provide.

[0008]

In order to achieve the above object, a water purification system according to the present invention is characterized in that a back water area extending between an artificial island and a coastal area and a back water area extending between the artificial island and the coastal area are provided. Along with the boundary between the continuous outer waters, an underwater structure is set up so that the crown height is set lower than the high tide water level and higher than the low tide water level, and the back water area is set outside the water area. A waterway communicating with a water area is provided on the artificial island or the underwater structure, and a gate configured to open only when a water level of the outer water area falls below a water level of the rear water area is provided in the waterway.

Further, the water purification system according to the present invention comprises:
The gate is configured such that the gate is opened when a difference between the water level in the back water area and the water level in the outside water area exceeds a certain value.

Further, the water purification system according to the present invention comprises:
The gate is provided near a water bottom.

In the water purification system according to the present invention, the height of the top is set at the high tide water level along the boundary between the backwater area extending between the artificial island and the coastal area and the external water area connected to the backwater area. In addition to constructing an underwater structure that is set lower and higher than the low tide water level, a water channel that connects the backwater area to the outside water area is provided on the artificial island or underwater structure, and the water level of the outside water area is the backwater area. There is a gate in the channel that opens only when the water level falls below.

For this reason, at the time of high tide, water in the outer water area flows into the backwater area so as to pass over the top of the underwater structure. At this stage, the water level in the backwater area is lower than the water level in the outer water area, and therefore, the water pressure in the backwater area at the place where the gate is installed is lower than the water pressure in the outer water area. It is in a closed state, and the inflow from the external water area continues until the water level in the backwater area becomes the same as the high water level.

On the other hand, when the water level in the outer water area falls below the top of the underwater structure after the high tide, the backwater area becomes a closed water area surrounded by the artificial island, the underwater structure, and the coastal area. Therefore, while the water level in the water area behind does not drop below the height of the top of the underwater structure, the water level in the external water area falls toward low tide. In other words, after the water level of the outer water area becomes equal to or lower than the height of the top of the underwater structure, the water level of the outer water area falls below the water level of the backwater area. Therefore, the water pressure in the backwater area at the gate exceeds the water pressure in the outside water area, the gate is operated to expose the waterway, and the water in the backwater area is discharged to the outside water area via the waterway.

As described above, the inflow from the outside water area to the backwater area and the outflow from the backwater area to the outside water area are repeatedly and reliably performed according to the ebb and flow, so that the water in the backwater area is prevented from being retained.

In particular, since the water flowing from the outer water area is surface water of the outer water area and contains a large amount of oxygen, the oxygen contributes to the decomposition of organic substances in the back water area to promote water purification.

[0016] Further, since the natural force utilizing the ebb and flow of the tide serves as the power for water exchange in the back water area, the water exchange in the back water area can be performed without particularly requiring artificial power.

The boundary between the backwater area and the outside water area connected to the backwater area is an artificial or virtual boundary to the last, and it is required that the backwater area has a special feature in topography. is not. That is, how to set the boundary between the backwater area and the outside water area connected to the backwater area is arbitrary irrespective of the topography.

The underwater structure has a water-stopping property such that a difference in water level between the backwater area and the outer water area can be realized, and the height of the top is set to be lower than the high tide water level and higher than the low tide water level. Any configuration may be used, but for example, a submerged bank may be used.

The relative positional relationship between the artificial island and the coast is arbitrary, and a part of the artificial island may be located in parallel with the rectangular planar artificial island facing the straight coast. This includes cases where people are connected to the coast.

Incidentally, when the rectangular planar artificial islands are located in parallel so as to face the linear coastal area, the underwater structures are arranged in parallel at opposite positions. It is conceivable that the underwater structure is linearly arranged from one end of the artificial island to the coast, and the other underwater structure is linearly arranged from the other end of the artificial island to the coast.

In the case where a part of the artificial island is connected to the coast, the underwater structure is installed on the side opposite to the side connected to the coast.

As described above, artificial islands are not limited to islands in a narrow sense that are completely separated from the coastal area, but include peninsulas that are partially connected to the coastal area. It shall be interpreted in a broad sense including.

The gate may be configured in any manner as long as the gate is opened only when the water level in the outer water area falls below the water level in the back water area, and adopts a structure similar to a check valve. Various configurations are conceivable, such as manual operation by workers while monitoring fluctuations in the tide level, and automatic opening / closing by detecting a difference in water pressure. When the gate is configured to open when the gate is open, even if the tide level of the outer water area falls after the high tide, the water level of the backwater area is maintained for a while, for example, the outer water area has become low tide Only when will the gate open.

In such a case, the water discharged from the backwater area to the outside water area flows out at a stretch, and the improvement of the water exchange efficiency can be expected.

The gate may be configured so that the gate is opened when the difference between the water level in the back water area and the water level in the outside water area exceeds a certain value. It is possible to use a locking mechanism including a claw that locks the gear.

The water channel may be of any configuration as long as the water area behind it can communicate with the external water area, and it does not matter whether it is installed on an artificial island or an underwater structure.
Incidentally, in the case of installation on an artificial island, it is conceivable that the artificial island is configured as a culvert-like underwater tunnel that penetrates the ground of the artificial island.

Here, the depth of the water channel is arbitrary. However, when the gate is provided near the bottom of the water, it is possible to preferentially discharge the bottom water, which tends to become deoxygenated, to the outside water area. Therefore, it is possible to reliably improve the water quality of the backwater area, in combination with the inflow action from the outer water area mainly composed of oxygen-rich surface water.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water purification system according to the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

FIGS. 1 and 2 show a water purification system 1 according to this embodiment. FIG. 1 is a plan view and FIG.
2A is a cross-sectional view taken along line AA of FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB of FIG. As shown in these drawings, the water purification system 1 according to the present embodiment includes an artificial island 2
Along the boundary between the backwater body 4 extending between the seawater and the coastal part 3 and the outer water body 5 connected to the backwater body, the underwater structures 6, 6
And a water channel 7 that connects the back water area 4 to the outside water area 5 is provided on the artificial island 2, and a gate 8 configured to open only when the water level of the outside water area 5 is lower than the water level of the back water area 4 is provided. 7 is provided on the water area 4 side.

The rectangular planar artificial island 2 is located parallel to the straight coast 3 so as to face the same, and one underwater structure 6 is linearly arranged from one end of the artificial island 2 to the coast 3. At the same time, the other underwater structure 6 is linearly arranged from the other end of the artificial island 2 to the shore 3.

The underwater structure 6, as best seen in FIG. 2 (a), the Yes constituted by latent bank consisting of concrete trapezoidal cross-section, Tentan height H is lower ebb than tide when the water level H ₁ It is constructed so as to be higher than when the water level H _2.

As can be seen clearly in FIG.
A culvert-like underwater tunnel penetrating the ground of the artificial island 2 is provided on the water bottom 9 so that the back water area 4 can communicate with the outside water area 5.

The gate 8 is installed at the entrance opening of the water channel 7 on the side of the back water area 4, and the water level of the outer water area 5 is set to the back water area 4.
It is configured to open only when the water level falls below the water level.

FIG. 3 is a detailed view showing the gate 8.
(a) is a front view, (b) is a horizontal sectional view along CC line.
As shown in the figure, the gate 8 includes a pair of hinged doors 11,
The hinge portions 13 of the hinged door are fixed to a pair of steel plates 12 attached to the side wall of the artificial island 2 by welding or the like. Note that a return spring (not shown) is built in the hinge portion 13 of the hinge door 11, and the hinge doors 11 and 11 are closed by the action of the return spring when the water pressure acting from both sides is the same. Has become.

Therefore, the water area 4 behind the gate 8
When the water pressure exceeds the water pressure of the external water area 5, that is, the water pressure of the water channel 7 communicating with the external water area, the hinged doors 11, 11
As shown in FIG. 3B, the gates 8 are opened by rotating toward the water channel 7 respectively. On the other hand, when the water pressure of the waterway 7 exceeds the water pressure of the backwater area 4, the hinge doors 11, 11 rotate toward the backwater area 4, but the steel plates 12,
12 and the rotation is restricted. Therefore, gate 8
Does not open to the backwater area 4 side.

In the water purification system 1 according to the present embodiment, as shown in FIG.
When the water level exceeds the top height H of the underwater structure 6, the water in the external water area 5 flows over the top end of the underwater structure 6 and flows into the rear water area 4. At this stage, the water level of the back water area 4 is lower than the water level of the outer water area 5 and, therefore, the water pressure of the back water area 4 at the place where the gate 8 is installed is lower than the water pressure of the outer water area 5. Does not work,
The waterway 7 is in a closed state, and water does not flow from the waterway 7 into the rear water area 4. Therefore, until the water level behind water 4 is the same as the water level H ₁ at high tide, followed by flow of water from the outer water 5.

On the other hand, at the time of ebb tide, as shown in FIG. 4B, the water level of the outer water area 5 is set to the top height H of the underwater structure 6.
When the water level falls below the upper limit, the water level in the back water area 4 is a closed water area surrounded by the artificial island 2, the underwater structures 6, 6 and the coastal part 3, so that the water level in the back water area is higher than the top of the underwater structure 6. H
While the water level does not drop below, the water level of the outer water area 5 falls toward low tide. That is, after the water level of the outer water area 5 becomes equal to or lower than the top height H of the underwater structure 6, the water level of the outer water area 5 becomes lower than the water level of the back water area 4. Therefore, the water pressure in the back water area 4 at the gate 8 is reduced
5 (a), the gate 8 is operated to expose the water channel 7, and the water in the rear water area 4 is discharged to the outside water area 5 through the water channel 7. As shown in FIG.

This discharge continues until the water levels of the backwater area 4 and the outer water area 5 become equal. At low tide, as shown in FIG. 5B, the water level of the backwater area 4 becomes the water level H of the outer water area 5 at low tide.
Same as ₂ . Therefore, there is no difference between the water pressure in the back water area 4 and the water pressure in the outside water area 5, so that the gate 8 is closed and the waterway 7 is closed, and in such a state, the tide changes again to full tide.

As described above, according to the water area purification system 1 according to the present embodiment, the inflow from the outside water area 5 to the back water area 4 and the outflow from the back water area 4 to the outside water area 5 repeatedly and reliably in response to the ebb and flow. Therefore, stagnation of water in the back water area 4 can be prevented beforehand.

In particular, since the water flowing from the outer water area 5 is surface water of the outer water area 5 and contains a large amount of oxygen, such oxygen contributes to decomposition of organic substances in the back water area 4 to promote water purification. be able to.

Since the natural force utilizing the ebb and flow of the tide serves as the power for water exchange in the back water area 4, the water exchange in the back water area 4 can be performed without any need for artificial power.

In the water purification system 1 according to the present embodiment, since the gate 8 is provided near the water bottom 9, the bottom water in the back water 4, which tends to become deoxygenated, is preferentially discharged to the outside water 5. can do. Therefore, the water quality of the back water area 4 can be reliably improved in combination with the inflow action from the outer water area 5 mainly composed of oxygen-rich surface water.

In the present embodiment, the artificial island 2 is an island-like structure completely separated from the coastal part 3, but the artificial island 2 is not limited to an island in a narrow sense. As shown in FIG. 6, an artificial island 22 similar to a peninsula partially connected to the coastal part 3 may be used. In the case where a part of the artificial island is connected to the coast 3, the underwater structure 6 is to be installed on the side opposite to the side connected to the coast 3, as shown in FIG. Becomes

In this embodiment, the waterway 7 is connected to the artificial island 2.
The waterway 7 is located at the bottom of the
Any structure may be used as long as the artificial island 2 and the underwater structure 6, 6 can be connected to the bottom of the underwater structures 6, 6, respectively. 6 may be installed in both.

In the present embodiment, the gate 8 is a double-opening automatic opening / closing door comprising a pair of hinged doors 11 with built-in return springs. However, the configuration of the gate is not limited to this. Alternatively, the door may be a one-sided door composed of a single door, or may be a door manually opened and closed by an operator while monitoring a change in tide level.

In the present embodiment, the gate 8 is configured to be opened only when the water level of the outer water area 5 is lower than the water level of the back water area 4. However, the gate 8 is replaced with the water level of the back water area 4 and the water level of the outer water area 5. A gate configured to open when the difference from the water level exceeds a certain value may be adopted. In this way, even if the tide level of the outer water area 5 drops below the top height H of the underwater structure 6 after the high tide, the gate does not open, and the water level of the back water area 4 is maintained for a while.
For example, the gate will be opened only when the outside water area 5 becomes low tide.

In such a case, from the back water area 4 to the outside water area 5
The water discharged into the basin flows out at once, and the improvement of the effectiveness of water exchange can be expected.

The gate may be configured so that the gate is opened when the difference between the water level in the back water area 4 and the water level in the outside water area 5 exceeds a certain value.
It is possible to use a locking mechanism including a gear and a claw that locks the gear.

[0049]

As described above, according to the water area purification system of the present invention, the inflow from the outside water area to the backwater area and the outflow from the backwater area to the outside water area are repeatedly and reliably performed in response to the ebb and flow. In addition, stagnation of water in the backwater area is prevented beforehand, water pollution in the backwater area is improved, and a favorable water quality environment can be maintained.

[0050]

[Brief description of the drawings]

FIG. 1 is a plan view showing a water purification system according to an embodiment.

FIGS. 2A and 2B are views showing a water purification system according to the embodiment, in which FIG. 2A is a cross-sectional view along line AA, and FIG. 2B is a cross-sectional view along line BB.

FIG. 3 is a detailed view showing a gate of the water purification system according to the embodiment, (a) is a front view, and (b) is a horizontal cross-sectional view along the line CC.

FIG. 4 is a view showing the operation of the water purification system according to the embodiment;

FIG. 5 is a view showing an operation of the water area purification system according to the embodiment.

FIG. 6 is a plan view showing a water purification system according to a modification of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water purification system 2,22 Artificial island 3 Coastal area 4 Backwater area 5 Outer water area 6 Underwater structure 7 Waterway 8 Gate 9 Water bottom

Continuation of the front page (72) Inventor Tomohiro Shishikura 2-15-2 Konan, Minato-ku, Tokyo Obayashi Corporation Tokyo head office F term (reference) 4D029 AA03 BB11

Claims (3)

[Claims] Along a boundary between a backwater area extending between an artificial island and a coastal area and an outer water area connected to the backwater area, a height of the crown is lower than a high tide water level and a lower tide water level. Along with constructing an underwater structure that is set to be high, a waterway that connects the backwater area to the outside water area is provided on the artificial island or the underwater structure, and the water level of the outside water area is the water level of the backwater area. A water area purification system, wherein a gate configured to open only when the water flow falls below the threshold is provided in the waterway. 2. The water area purification system according to claim 1, wherein the gate is configured to open when the difference between the water level in the back water area and the water level in the outside water area exceeds a predetermined value. 3. The gate according to claim 1, wherein the gate is provided near the bottom of the water.
Water purification system as described.