JP2007077693A - Closed water purification fence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the increase of phytoplankton so that streams of water in an upper layer and a lower layer can be almost and completely separated from each other in the closed water. <P>SOLUTION: River water abundant in inorganic nutritive collides with a fence 2 suspended from a float 1 to become a downward flow, and it becomes a stream going to further the bottom of a lake by a lower separate flow plate 4. The river water containing nutritive salts of nitrogen and phosphorus, etc. induced to the bottom of the lake drifts away an aphotic zone of the bottom of the lake, and probability returning it to the upper layer becomes very low. Since the phytoplankton can not perform photosynthesis in the aphotic layer, its increase is suppressed. Since the nutritive salts are absorbed in sediment in the bottom of the lake or are solidified to precipitate while drifting away the bottom of the lake, it is prevented that the nutritive salts are supplied to the upper layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water quality improvement fence for the purpose of improving water quality in closed water areas such as dams and lakes, and the flow quality is improved by generating a flow in the upper and lower portions of the inflow water from a river by a fence installed in the water. Is.

  As shown in Fig. 2, when the river water containing nutrients flows in the upstream part of the reservoir formed by the dam, the upstream return flow is in the upper part of the reservoir and the downstream part is in the lower part. A flow occurs, and the upstream return flow joins the downstream flow at the inflow of the river water.

  Because phytoplankton has phototaxis, it moves to the upper layer in search of light, so phytoplankton is likely to accumulate in the upstream of the reservoir, and river water contains inorganic nutrients such as nitrogen and phosphorus Therefore, a large amount of phytoplankton is likely to occur.

  As a measure for preventing a large amount of phytoplankton, a water quality improvement device is known in which a fence is installed at the inflow portion of a river reservoir as shown in FIG. In this water quality improvement device, a float is installed in the transverse direction of the river inflow part of the reservoir, and a canvas fence is suspended from the float in the water of the reservoir. The fence extends in the vertical direction to a depth at which sunlight does not reach, and a weight is attached to the lower end of the fence so that it can be maintained almost vertically in the water even when there is a water flow.

The upper layer portion of the reservoir is separated into an upstream side and a downstream side by this fence, and the river water is directed to the lower layer along the fence, so that the upper layer water on the downstream side is less likely to contact the river water. Since river water descends along the fence, it flows into deep water layers where sunlight does not reach, and nutrients contained in river water are no longer supplied to the upper water, preventing the mass production of phytoplankton. The
Japanese Patent Laid-Open No. 10-60874 JP 2005-36453 A

  However, as with conventional closed water purification systems, simply installing a fence does not provide sufficient control of the flow in the reservoir, and the nutrient-rich lower-layer water sourced from river water is transported to the upper layer. Under the light, phytoplankton and blue-green algae grow in large quantities near the water surface, resulting in a problem that the water purification function is lowered.

  Therefore, in the present invention, in the closed water area, the upper and lower water flows are almost completely separated, the lower water rises and reaches the light layer near the water surface, and the phytoplankton and the blue water. It is to prevent the development from occurring.

  A fence is suspended from a float floated on the water surface, and two shunt plates for controlling two water flows are provided at the lower end of the fence. The upper partial flow plate is disposed horizontally among the flow dividing plates, and the lower partial flow plate is inclined downward to prevent mixing of the upper layer water and the lower layer water.

  Further, by making the inclination angle of the lower partial flow plate variable, the lower partial flow plate can be set to the optimum inclination angle according to the installation environment.

  The present invention suspends a fence on a float that floats on the water surface, and provides two shunt plates at the lower end of the fence in the direction of water flow. Since the flow plate is installed in a slanted downward direction, water separation between the lower layer and the upper layer is almost complete, the flow of water in the closed water area can be controlled, and water quality purification in the closed water area can be achieved. Can be achieved.

  In addition, by changing the angle of the lower partial flow plate, it can be set to an optimum state according to the shape of the lake that is a closed water area, the flow velocity of the river, etc., and the upper and lower water of the lake is mixed. Can be prevented.

  Furthermore, since the present invention has a simple structure and simple installation work, it can be installed at a low cost, and the maintenance cost is not so increased as compared with a conventional fence.

  Next, an embodiment of a closed water purification apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of a fence for improving water quality according to the present invention, and shows a state in which river water containing nutrients flows into a closed water area such as a lake formed by a dam. In general, the depth of the inflow of the closed water area is relatively shallow and becomes deeper as the distance from the river inflow increases. FIG. 1 illustrates only the vicinity of an inflow portion such as a reservoir into which a river flows, and an actual lake extends to the right side of the figure.

  The fence for improving water quality according to the present invention is installed in the upstream portion of the reservoir. That is, the float 1 is floated on the water surface upstream of the reservoir, and the fence 2 is suspended from the float 1 in the water of the reservoir. A fence 2 or the like is used as the fence 2. Although not shown, a weight is provided at the lower end of the fence 2 to stabilize the fence.

  Two shunt plates 3 and 4 are attached to the lower end of the fence 2. The flow dividing plates are an upper partial flow plate 3 and a lower partial flow plate 4, and the upper partial flow plate 3 is horizontally fixed to the lower end of the fence 2. The lower partial flow plate 4 is disposed obliquely to guide the flowing river water to the bottom of the lake, and is attached so as to be rotatable around an axis provided at the lower end of the fence 2. The inclination angle of the lower partial flow plate 4 can be changed.

  The inclination angle of the lower partial flow plate 4 is appropriately changed according to factors such as the topography such as the inclination angle of the lake bottom, the flow velocity of the flowing river water, and the depth of the fence.

  Similarly, the size of the flow dividing plate is appropriately determined based on the above factors. The material of the flow dividing plate is preferably lightweight and corrosion resistant, and is selected from plastic, metal, canvas or other cloth.

  River water rich in nutrients flowing in from the river collides with the fence 2 and descends along the fence 2 and flows into the closed water area from the lower side of the fence. At that time, the lower partial flow plate 4 generates a flow that guides the flowing river water toward the bottom of the lake. And the river water containing nutrients such as nitrogen and phosphorus induced toward the bottom of the lake drifts in the lightless layer on the bottom of the lake, and the probability of returning to the upper layer becomes very low. In the non-light layer, plankton cannot perform activities such as photosynthesis, so that even if nutrients are present, growth is suppressed. And while drifting in the bottom of the lake, the nutrients are adsorbed by the sediment at the bottom of the lake or solidify and settle.

  In the upper layer, a return flow from the downstream side toward the upstream side is generated. And this return flow collides with the fence 2 and descends along the fence 2, but since the flow to the lower layer is prevented by the horizontal upper partial flow plate 3 at the lower end of the fence 2, it becomes a flow circulating in the upper layer. The possibility of mixing with the river water led to the lower layer by the lower partial flow plate 4 is almost eliminated. Therefore, no nutrient salt is supplied to the luminescent layer, resulting in an oligotrophic state, and the possibility that phytoplankton will grow is very low.

  By adjusting the inclination angle of the lower partial flow plate 4 to control the flow of water in the upper layer of the lake and the nutrient-rich water in the lower layer, it is possible to more effectively prevent the two from mixing.

  Selection of the installation location of the fence 2 with a diversion board of this invention, and determination of the inclination angle of a lower partial flow board analyze the circulation of the water in a lake by simulation, and select an optimal position and angle.

It is sectional drawing of the installation state of the fence of the Example of this invention. It is explanatory drawing of the flow of the river water which flows in into a closed water area. It is sectional drawing of the installation state of the conventional fence.

Explanation of symbols

1 Float 2 Fence 3 Upper partial flow plate 4 Lower partial flow plate

Claims (2)

A closed water purification fence consisting of a float and a fence suspended on the float, and provided with a horizontal upper partial flow plate and a lower partial flow plate inclined downward at the lower end of the fence. The closed water purification fence according to claim 1, wherein the inclination angle of the lower partial flow plate is variable.

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