JP4627716B2 - Construction method of sand filtration sedimentation basin and sand filtration sedimentation basin - Google Patents

Description

  The present invention relates to a sand filtration sedimentation basin configured to filter water to be treated by being built on the ground and passing through a sand layer, and a construction method thereof.

  Wastewater containing a large amount of earth and sand is generated at sites such as excavation work for tunnels and pile holes, and dredging work for rivers and lakes. Conventionally, such wastewater is transported to treatment plants by tank lorries. There are many cases. However, if the generated wastewater is transported as it is, the amount of wastewater is large, and thus transporting it takes a lot of cost and labor. For this reason, it is preferable to filter wastewater at a construction site before transportation to separate earth and sand to reduce the amount of wastewater, and a relatively small filtration device that can be used at a construction site is desired. As a general filtration device, for example, it has a sealed tank and a sand layer filled in the tank, the water to be treated introduced from above the tank is filtered through the sand layer, and the filtered water is stored in the tank. A filtration device configured to discharge from below is known (see Patent Document 1).

JP-A-5-154309

  However, the filtration device described in Patent Document 1 has a configuration in which a sand layer or the like is disposed in a sealed tank. Therefore, in order to use this filtration device in the field, a comparison that has been assembled in advance. Therefore, there is a problem that it is necessary to transport a large-sized filtration device, and the transport work is difficult. And since the sand layer is the structure in which the tank is filled and the to-be-processed water inlet is provided in the upper side of the sand layer, the height of the whole apparatus will become high and the workability | operativity will fall. There is a fear. Further, since the water to be treated is introduced from above the sand layer, there is a problem that deposits such as sludge are likely to be deposited on the surface of the sand layer and the filtration function of the sand layer is likely to be lowered. In addition, from the viewpoint of enabling easy assembly at the site, it can be considered to reduce the size of the apparatus. However, as the amount of wastewater increases, the processing capacity of small devices is limited, and sand filtration devices that are built simply from the standpoint of improving assembly at the site can be treated at large sites where a large amount of wastewater is generated. It is possible that this would cause a delay.

  The object of the present invention is to facilitate the transportation work of the constituent members, can be easily constructed on site, and can also suppress the deterioration of workability, and suppress the decrease of the sand layer filtration function. It is also possible to realize wastewater treatment by sand filtration that can suppress the delay of treatment even at a site where a large amount of wastewater is generated.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a method for constructing a sand filtration sedimentation basin according to the present invention includes a drilling hole forming step of forming a drilling hole in the ground, and a partition wall and a water permeable filter disposed in the drilling hole. By dividing the inside of the excavation hole, a filtration chamber for filtering the water to be treated and a water tank chamber that is adjacent to the filtration chamber through the filter in the horizontal direction and in which the water to be treated is stored are disposed in the excavation hole. A horizontal filtration region forming step to be formed, a water collection material disposing step of disposing a water collecting material formed as a cylindrical body having self-retaining properties and water permeability in the filtration chamber; A sand layer forming step of forming a sand layer by filling the filtration chamber with sand so as to cover the water collecting material, and constructing a sand filtration sedimentation basin for filtering water to be treated by passing the sand layer It is characterized by that.

  Moreover, the sand filtration sedimentation basin according to the first aspect of the present invention for achieving the above object includes a drilling hole formed in the ground, a partition wall disposed in the drilling hole, and a filter having water permeability. A filtration chamber that is formed in the excavation hole by being partitioned by the partition wall and the filter and performs filtration of water to be treated, and is adjacent to the filtration chamber in the horizontal direction via the filter and water to be treated. A water tank chamber in which water is stored, a water collecting material which is disposed in the filtration chamber and has a self-holding property and a water-permeable cylindrical body, and sand in the filtration chamber so as to cover the water collection material And a sand layer formed by being filled, and the water to be treated is filtered by passing through the sand layer.

  Moreover, the sand filtration sedimentation basin according to the second aspect of the present invention for achieving the above object includes a drilling hole forming step of forming a drilling hole in the ground, a partition wall and a water permeable filter in the drilling hole. By separating the inside of the excavation hole, a filtration chamber for filtering the water to be treated and a water tank chamber adjacent to the filtration chamber through the filter in the horizontal direction and storing the water to be treated are provided. A horizontal filtration region forming step formed in the excavation hole, and a water collection material arrangement for arranging a water collection material formed as a cylindrical body having self-shape retaining property and water permeability in the filtration chamber. It is constructed through a step and a sand layer forming step of forming a sand layer by filling the filtration chamber with sand so as to cover the water collecting material, and the water to be treated is filtered by passing the sand layer. It is characterized by performing.

  According to the construction method of the sand filtration sedimentation basin of the present invention and the sand filtration sedimentation basin, the partition wall, the filter, and the water collecting material are transported to the site, the excavation hole is formed at the site, and the partition material is formed therein. It is only necessary to arrange a filter and a water collecting material, and it is possible to obtain a sand filtration sedimentation basin that is easy to carry and can be easily constructed on site. In addition, since the filtration chamber and aquarium chamber are formed in the excavation hole excavated in the ground, the height of the sand filtration sedimentation basin does not exceed the height of the ground, making it easy to throw in wastewater and improving workability. Can be improved. Moreover, the magnitude | size of a sand filtration sedimentation basin can be arbitrarily set by setting the magnitude | size of the excavation hole formed in the ground of a spot arbitrarily. For this reason, the processing capacity of the sand filtration sedimentation basin can be set as appropriate according to the amount of wastewater generated at the site, and even when a large amount of wastewater is generated, processing delay can be suppressed.

  In addition, in the sand filtration sedimentation basin of the present invention and the sand filtration sedimentation basin constructed by the construction method of the present invention, the water to be treated (waste water) to be filtered is introduced into the water tank chamber and stored in it. Then, it passes through a filter having water permeability and flows into a filtration chamber arranged adjacent to the water tank chamber. At this time, the earth and sand contained in the water to be treated stored in the aquarium chamber sinks in the aquarium chamber by gravity while moving in the horizontal direction. And the to-be-processed water which flowed into the filtration chamber will be filtered by passing a sand layer, and further, the filtered water will flow into the water collecting material covered with the sand layer, and through the water collecting material It is discharged outside the partition wall. Thus, in this sand filtration sedimentation basin, the water to be treated flows into the sand layer from the horizontal direction and is filtered, so that the water to be treated is introduced from above the sand layer as in the prior art. Moreover, it can suppress that the sand filtration function of a sand layer falls because deposits, such as sludge, accumulate on the surface of a sand layer.

  Therefore, according to the structure of this invention, it can suppress that a conveyance work is easy and can construct | assemble easily on-site, and also causes a fall of workability | operativity, and can suppress that the filtration function of a sand layer falls. In addition, it is possible to realize wastewater treatment by sand filtration that can suppress the delay of treatment even at a site where a large amount of wastewater is generated.

  Further, the construction method of the sand filtration sedimentation basin according to the present invention is a cylindrical woven fabric having a self-retaining property by using a yarn having bending resilience in at least a part of the weft in the water collecting material disposing step. It is desirable to dispose the cylindrical body formed as a water collecting material.

  Further, in the sand filtration sedimentation basin according to the present invention, the cylindrical body is formed of a cylindrical woven fabric having a self-retaining property using a yarn having a bending resilience for at least a part of the weft. Is desirable.

  According to this configuration, the water collecting material is formed as a cylindrical woven fabric having self-retaining properties and has water permeability, so it is necessary to bother to form a plurality of holes in order to make the water collecting material water permeable. There is no. And it is lightweight compared with the synthetic resin and metal water collecting material which have a some hole, and the handling at the time of conveyance and construction of a sand filtration sedimentation basin is easy. Moreover, it is also possible to arrange | position in the state bent in the filtration chamber. Furthermore, a conventional sand filtration device does not require a highly water-permeable layer such as a gravel layer that is generally provided, which makes it easier to disassemble and construct in the field. Furthermore, by appropriately adjusting the weave structure of the water collecting material, it is possible to change the water permeability of the water collecting material according to the type of water to be treated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The sand filtration sedimentation basin according to the embodiment of the present invention can be widely used as a filter for water to be treated by passing a sand layer. For example, the sand filtration sedimentation basin according to the present embodiment can be used when filtering wastewater generated during excavation work for tunnels and pile holes, dredging work for mud in rivers and lakes, and the like.

  FIG. 1 is a cross-sectional view illustrating a sand filtration sedimentation basin 1 according to an embodiment of the present invention, and FIG. 2 is a plan view of the sand filtration sedimentation basin 1. FIG. 1 is a cross-sectional view corresponding to the position taken along line I-I in FIG. As shown in FIGS. 1 and 2, the sand filtration sedimentation basin 1 includes an excavation hole 11, a partition wall 12, a filter 13, a filtration chamber 15, a water tank chamber 16, a sand layer 17, a water collecting material 18, and the like. Yes.

  As shown in FIGS. 1 and 2, the excavation hole 11 is formed by excavation at a site where wastewater is generated or at the ground 10 near the site. For example, the excavation hole 11 is provided so as to partition a rectangular parallelepiped space therein, but can be set in various shapes according to the situation at the site.

  As shown well in FIG. 2, the partition wall 12 is formed by, for example, a plurality of blocks 12 a standing in the vertical direction in the excavation hole 11 and arranged in a plane. The partition wall 12 is disposed as a wall extending between both side surfaces on the long side of the excavation hole 11, and is disposed so as to partition the excavation hole 11.

  The filter 13 is erected in the vertical direction in the excavation hole 11 and is disposed in parallel with the partition wall 12 as illustrated in FIG. The filter 13 is composed of a water-permeable mesh sheet and expanded metal. For example, the mesh sheet is formed as a sheet having an opening of 2.5 mm in length × 2.5 mm in width, and the expanded metal is formed as a net having a diamond-shaped opening having a diagonal length of 36 mm × 101.6 mm. Has been.

  The filtration chamber 15 and the water tank chamber 16 are formed in the excavation hole 11 by being partitioned by the partition wall 12 and the filter 13, and are arranged side by side in the horizontal direction. The filtration chamber 15 is disposed between the partition wall 12 and the filter 13, and the water tank chamber 16 is disposed adjacent to the filtration chamber 15 via the filter 13 in the horizontal direction. As shown in FIG. 1, the water tank chamber 16 is formed as a compartment in which waste water that is to-be-treated water is introduced from above and stored. Further, the filtration chamber 15 is formed as a section for performing filtration by allowing the water to be treated 20 stored in the water tank chamber 16 to pass through the sand layer 17.

  As shown by dotted lines in FIGS. 1 and 2, the water collecting material 18 is disposed in the filtration chamber 15 and is formed as a cylindrical body having self-holding properties and water permeability. In the filtration chamber 15, the water collection material 18 is assembled and arranged in a spiral shape in the vertical direction, for example.

  As shown in FIG. 3, the water collecting material 18 is composed of a tubular woven fabric 21 woven in an annular shape using warps 22 and wefts 23, and has water permeability. Here, a yarn having a bending resilience is used for at least a part of the weft 23, and the tubular woven fabric 21 constituting the water collecting material 18 has a self-retaining property as described above. And the water permeability of the water collecting material 18 can be changed according to the kind of waste water etc. by adjusting the weave structure of the water collecting material 18 suitably. An example of such a water collecting material 18 is an annularly woven fabric composed of warp yarn 22 made of polyester fiber having a thickness of 6600 dtex and SUS wire having a thickness of φ1.6 mm, and a weft yarn 23 having a density of 40 P / 10 cm. The cylindrical woven fabric 21 having a diameter of 51 mm can be used. One end of the water collecting material 18 is in a closed state, and the other end of the water collecting material 18 is fitted into a hole (not shown) provided in the partition wall 12 as shown in FIGS. 1 and 2. Thus, the pipe 19 is connected to the outside of the filtration chamber 15.

  As shown in FIGS. 1 and 2, the sand layer 17 is formed by filling the filtration chamber 15 with sand so as to cover the water collecting material 18. In addition, the sand filtration sedimentation basin 1 of this embodiment is intended to remove suspended substances such as sand contained in the wastewater by the sand layer 17, and to remove harmful substances dissolved in the wastewater. is not. Therefore, the sand layer 17 is not limited to a specific type.

  In the sand filtration sedimentation basin 1 having the above-described configuration, as shown in FIG. 1, when the water to be treated 20 is stored in the water tank chamber 16, the earth and sand contained in the water to be treated 20 settles by gravity, and the water tank chamber 16. As shown by arrow A in the figure, the treated water 20 flows in the horizontal direction into the filtration chamber 15 through the filter 13 having water permeability, and is formed into the sand layer 17. It penetrates. At this time, the water 20 to be treated is filtered by the sand layer 17. The water filtered by the sand layer 17 flows into the water collecting material 18 and is discharged to the outside of the filtration chamber 15 through the pipe 19 as indicated by an arrow B in the figure.

  In this sand filtration sedimentation basin 1, since the earth and sand contained in the water 20 to be treated stored in the water tank chamber 16 gradually settles by gravity to form sedimentary earth and sand, the filter surface 13a in the filter 13 (FIG. 2). It takes a considerable amount of time to cover a large portion of (see) with earth and sand, and the processing capacity in the sand filtration sedimentation basin 1 does not decrease immediately. Therefore, this sand filtration sedimentation basin 1 is particularly suitable for filtering water to be treated containing very fine particles such as red soil. Moreover, in the sand filtration sedimentation basin 1, since the filter surface 13a is provided along the vertical direction, even if earth and sand are deposited on the filter surface 13a, it can be easily knocked down, and good maintainability is obtained. be able to. Moreover, in the sand filtration sedimentation basin 1, since the flow of the to-be-processed water 18 is horizontal, even if the opening of the water collecting material 18 is enlarged and the thickness of the sand layer 17 is increased, it is only thick in the horizontal direction. It can suppress that the depth of the sand filtration sedimentation basin 1 becomes deep. For this reason, the degree of freedom of the design range regarding the degree of opening of the water collecting material 18 and the thickness of the sand layer 17 can be increased in accordance with the conditions at the site.

  Next, the construction method of the sand filtration sedimentation basin 1 described above will be described. The sand filtration sedimentation basin 1 is constructed through an excavation hole forming step, a horizontal filtration region forming step, and a water collecting material disposing step. That is, the construction method of the sand filtration sedimentation basin 1 includes an excavation hole forming step, a horizontal filtration region forming step, and a water collecting material disposing step.

  When constructing the sand filtration sedimentation basin 1, as shown in the cross-sectional view of FIG. 4, first, an excavation hole forming step of excavating the ground 10 to form the excavation hole 11 is performed. Next, as shown in FIG. 6, which is a view taken along the line VI of FIGS. 5 and 5, a plurality of blocks 14 are stacked in the excavation hole 11 at positions adjacent to the inner wall of the excavation hole 11. Then, as shown in FIG. 7 which is a view taken along the line VII in FIGS. 5 and 5, the partition wall 12 is formed by arranging the plurality of blocks 12 a so as to be separated from the block 14 and stacked in a plane. Next, as shown in FIG. 9 which is a view taken along line IX in FIG. 8 and FIG. 8, the mesh is vertically arranged so as to close the opening formed between the standing blocks 14. The sheet 13 and the expanded metal are arranged, and are erected and fixed to one side of the block 14 by an appropriate means to form the filter 13. In this way, the partition wall 12 and the filter 13 are arranged in the excavation hole 11 to partition the excavation hole 11, thereby excavating the filtration chamber 15 and the aquarium chamber 16 arranged horizontally through the filter 13. A horizontal filtration region forming step formed in the hole 11 is performed.

  When the filtration chamber 15 is formed, a water collection material disposing step of disposing the water collection material 18 formed of the tubular fabric 21 having the above-described configuration in the filtration chamber 15 is performed. In the water collecting material arranging step, as shown in FIG. 10, the water collecting material 18 is arranged in a shape that is spirally wound and stacked in the vertical direction. In the present embodiment, a state in which three water collecting members 18 are disposed is illustrated, but the number of the water collecting members 18 is appropriately set according to the volume of the excavation hole 11. The pipe 19 is inserted into a hole provided in the partition wall 12 so as to be fitted therein, and the pipe 19 and the end of the water collecting material 18 are connected.

  When the water collecting material 18 is disposed in the filtration chamber 15, the sand layer 17 is then formed by filling the filtration chamber 15 with sand so as to cover the water collecting material 18 as shown in FIG. 11. A sand layer forming step is performed. Thereby, the sand filtration sedimentation basin 1 is constructed. When the sand filtration sedimentation basin 1 is constructed, the water to be treated can be introduced into the water tank chamber 16 and filtered in the filtration chamber 15 as described above.

  Moreover, FIG. 12 is sectional drawing which shows the sand filtration sedimentation basin 2 which concerns on a modification. In addition, about the element similar to the sand filtration settling tank 1, the same code | symbol is attached | subjected and description is omitted. The sand filtration sedimentation basin 2 is different from the sand filtration sedimentation basin 1 in that it is further provided with a preliminary water tank chamber 24. The preliminary water tank chamber 24 is formed as an excavation hole arranged side by side with respect to the excavation hole 11 via the bank portion 27. In the bank portion 27, a pipe or the like is embedded to form a communication path 25 that allows the water tank chamber 16 and the reserve water tank chamber 24 to communicate with each other.

  In the sand filtration sedimentation basin 2, the water to be treated 20 is first put into the preliminary water tank chamber 24. When the water to be treated 20 is stored in the preliminary water tank chamber 24, the earth and sand contained in the water to be treated 20 is settled by gravity, and a layer of sedimentary earth and sand 26 is formed on the bottom of the preliminary water tank chamber 24. As shown, the treated water 20 passes through the communication passage 25 and flows into the water tank chamber 16. After flowing into the water tank chamber 16, the water to be treated 20 is filtered in the same manner as the sand filtration sedimentation basin 1. According to the sand filtration sedimentation basin 2, by providing the preliminary water tank chamber 24 as a pretreatment process for the water tank chamber 16, the water to be treated can be treated in multiple stages.

Next, the result of the filtration experiment of the to-be-processed water using the sand filtration sedimentation basin 2 mentioned above is demonstrated. In sand filtration sedimentation tank 2, both the depth of about 1.2 m (depth at full capacity is about 1m) provided a preliminary water tank chamber 24 of the water tank chamber 16 and about 25 m ³ of volume at approximately 10 m ^3, collecting As the water material 18, one having a diameter of 30 mm and a length of 80 m was used. The volume of the filtration chamber 15 was 3 m ³ , the drainage capacity was about 40 liters per minute, and the design was made so that the filtrate was drained in about 4 hours in the case of full water.

  When a filtration experiment of water to be treated (muddy water) was performed in the sand filtration sedimentation basin 2 described above, a drainage capacity of 60 liters per minute was exhibited when the water level was full, although it varied depending on the water level of the preliminary water tank chamber 24 and the water tank chamber 16. It was confirmed that the drainage capacity of 30 liters per minute was exhibited when the water level was 50 cm. When the turbidity unit SS (mg / liter), which is a unit indicating the amount of suspended solids, was evaluated, the turbidity of muddy water before filtration was 760 mg / liter, and the treated water after 1 hour from the start of the filtration treatment. The turbidity of (filtered water) was 137 mg / liter, the turbidity of treated water after 2 hours was 45 mg / liter, and the turbidity of the treated water thereafter was less than 45 mg / liter, which was the target. It was confirmed that 200 mg / liter or less can be sufficiently achieved. Immediately after the start of filtration, water with high turbidity is drained by the outflow of fine silt contained in the sand, but the turbidity is stable after the sand is washed. It was confirmed that low-grade water could be discharged reliably.

  As explained above, according to the construction method of the sand filtration sedimentation basin and the sand filtration sedimentation basin (1, 2) of this embodiment, members such as the partition wall 12, the filter 13, and the water collecting material 18 that are easy to transport are installed on the site. It is only necessary to form the excavation hole 11 at the site, and to arrange the partitioning material 12, the filter 13 and the water collecting material 18 therein, and the transportation work is easy and the construction is simple at the site. A sand filtration sedimentation basin can be obtained. Moreover, since the filtration chamber 15 and the water tank chamber 16 are formed in the excavation hole 11 excavated in the ground 10, the height of the sand filtration sedimentation basin (1, 2) does not exceed the height of the ground 10. Waste water charging operation is easy and workability can be improved. Moreover, the magnitude | size of the sand filtration sedimentation basin (1, 2) can be arbitrarily set by setting the magnitude | size of the excavation hole 11 formed in the ground 10 of a spot arbitrarily. For this reason, the processing capacity of the sand filtration sedimentation basin (1, 2) can be appropriately set according to the amount of wastewater generated at the site, and even when a large amount of wastewater is generated, the processing delay is suppressed. A large scale sand filtration sedimentation basin can be easily constructed.

  Moreover, in the sand filtration sedimentation basin (1, 2) of the present embodiment and the sand filtration sedimentation basin (1, 2) constructed by the construction method of the present embodiment, the treated water (waste water) to be filtered is When the water tank chamber 16 is charged and stored in the water tank chamber 16, it passes through the water-permeable filter 13 and flows into the filtration chamber 15 disposed adjacent to the water tank chamber 16. At this time, the earth and sand contained in the water to be treated stored in the water tank chamber 16 settles in the water tank chamber 16 by gravity while moving in the horizontal direction. And the to-be-processed water which flowed into the filtration chamber 15 will be filtered by passing the sand layer 17, and also the filtered water will flow into the water collection material 18 covered with the sand layer 17, and water collection will be carried out. It is discharged outside the partition wall 12 through the material 18. Thus, in this sand filtration sedimentation basin (1, 2), since the water to be treated flows into the sand layer 17 from the horizontal direction and is filtered, the water to be treated from above the sand layer as in the prior art. It is possible to suppress the sand filtration function of the sand layer from being deteriorated due to the accumulation of deposits such as sludge on the surface of the sand layer, compared with the case of introducing.

  Therefore, according to the construction method of the sand filtration sedimentation basin and the sand filtration sedimentation basin (1, 2) of the present embodiment, the transportation work is easy and can be easily constructed on site, and the workability may be reduced. In addition, it is possible to suppress wastewater filtration by sand filtration that can be suppressed, and that the filtration function of the sand layer can be prevented from being reduced, and that delay of treatment can be suppressed even at a site where a large amount of wastewater is generated.

  Moreover, according to the construction method of the sand filtration sedimentation basin and the sand filtration sedimentation basin (1, 2) of the present embodiment, the water collecting material 18 is formed as a tubular woven fabric 21 having self-retaining properties and is permeable to water. Therefore, it is not necessary to bother to form a plurality of holes in order to give the water collecting material 18 water permeability. And it is lightweight compared with the synthetic resin and metal water collecting material which have a some hole, and the handling at the time of conveyance and construction of a sand filtration sedimentation basin is easy. Moreover, it is also possible to arrange | position in the state bent in the filtration chamber. Further, a conventional sand filtration device does not require a layer having high water permeability such as a gravel layer that is generally provided, and the number of members to be used is small, and disassembly and construction on the site are further facilitated. Furthermore, by appropriately adjusting the weave structure of the water collecting material, it is possible to change the water permeability of the water collecting material according to the type of water to be treated.

  Further, in the sand filtration sedimentation basin (1, 2), the filter 13 is provided upright in the vertical direction, so that the filter surface 13a is hardly clogged, and a continuous filtration process for a long time is possible. Since the filter 13 is erected in the vertical direction, it can be knocked down even if sediment is accumulated, and maintenance is facilitated. Further, since the water to be treated flows in the horizontal direction, even if the opening of the water collecting material 18 is increased and the thickness of the sand layer 17 is increased, the sand filtration sedimentation basin (1, Since it can suppress that the depth of 2) becomes deep, the design range of the opening of the water collection material 18 and the thickness of the sand layer 17 will spread. In addition, since it is constructed on site, a preliminary water tank chamber 24 for pretreatment and the like can be appropriately formed as in the sand filtration sedimentation basin 2 in accordance with the situation on site and the required filtration performance. it can.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. . For example, the following modifications may be made.

(1) The sand filtration sedimentation basin formed so that a filter may become cross-sectional shape in which various unevenness | corrugations, such as a waveform shape, were provided in the horizontal direction may be sufficient. By using a filter with a cross-sectional shape with unevenness in the horizontal direction, it is possible to secure a large passage area of the water to be treated when the water to be treated passes from the water tank chamber to the filtration chamber and improve the filtration efficiency Can be made.

(2) A sand filtration sedimentation basin arranged so as to stand a coarse mesh filter for removing solid matter in the water tank chamber may be used. In this case, the aquarium chamber is partitioned by the coarse mesh filter into a first aquarium chamber on the filtration chamber side and a second aquarium chamber on the opposite side through the coarse filter. To-be-treated water is introduced from above.

It is sectional drawing of the sand filtration sedimentation basin which concerns on embodiment of this invention. It is a top view of the sand filtration sedimentation basin shown in FIG. It is a partially cutaway perspective view of the cylindrical woven fabric which comprises the water collecting material shown in FIG. It is sectional drawing explaining the construction method of the sand filtration sedimentation basin shown in FIG. It is sectional drawing explaining the construction method of the sand filtration sedimentation basin shown in FIG. FIG. 6 is a view taken in the direction of arrows VI in FIG. 5. It is a VII line arrow directional view of FIG. It is sectional drawing explaining the construction method of the sand filtration sedimentation basin shown in FIG. It is the IX arrow directional view of FIG. It is sectional drawing explaining the construction method of the sand filtration sedimentation basin shown in FIG. It is sectional drawing explaining the construction method of the sand filtration sedimentation basin shown in FIG. It is sectional drawing of the sand filtration sedimentation basin which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sand filtration sedimentation basin 10 Ground 11 Excavation hole 12 Partition material 13 Filter 15 Filtration room 16 Water tank room 17 Sand layer 18 Water collecting material 20 Water to be treated

Claims (5)

A drilling hole forming process for forming a drilling hole in the ground;
By arranging a partition wall and a water permeable filter in the excavation hole and partitioning the excavation hole, a filtration chamber for filtering water to be treated and the filtration chamber in the horizontal direction through the filter A horizontal filtration region forming step for forming a water tank chamber in the excavation hole that is adjacent and in which treated water is stored;
In the filtration chamber, a water collecting material disposing step of disposing a water collecting material that is formed as a cylindrical body having self-shape retaining property and water permeability,
A sand layer forming step of forming a sand layer by filling the filtration chamber with sand so as to cover the water collecting material;
With
A method for constructing a sand filtration sedimentation basin, comprising constructing a sand filtration sedimentation basin for filtering water to be treated by passing the sand layer.   In the water collecting material disposing step, the tubular body formed of a cylindrical woven fabric having a self-retaining property by using a yarn having a bending resilience for at least a part of the weft is disposed as the water collecting material. The sand filtration sedimentation basin construction method according to claim 1, wherein the sand filtration sedimentation basin is constructed. Excavation holes formed in the ground,
A partition wall disposed in the borehole and a filter having water permeability;
It is formed in the excavation hole by being partitioned by the partition wall and the filter, and a filtration chamber for filtering the water to be treated and the filtration chamber are adjacent to the filtration chamber through the filter in the horizontal direction and the water to be treated is A tank room,
A water collecting material which is disposed in the filtration chamber and has a self-holding property and is formed as a cylindrical body having water permeability;
A sand layer formed by filling the filtration chamber with sand so as to cover the water collecting material;
With
A sand filtration sedimentation basin characterized in that the water to be treated is filtered by passing through the sand layer.   The sand filter according to claim 3, wherein the cylindrical body is formed of a cylindrical woven fabric having a self-retaining property using a yarn having a bending resilience for at least a part of the weft. Settling pond. A drilling hole forming process for forming a drilling hole in the ground;
By arranging a partition wall and a water permeable filter in the excavation hole and partitioning the excavation hole, a filtration chamber for filtering water to be treated and the filtration chamber in the horizontal direction through the filter A horizontal filtration region forming step for forming a water tank chamber in the excavation hole that is adjacent and in which treated water is stored;
In the filtration chamber, a water collecting material disposing step of disposing a water collecting material that is formed as a cylindrical body having self-shape retaining property and water permeability,
A sand layer forming step of forming a sand layer by filling the filtration chamber with sand so as to cover the water collecting material;
Built through
A sand filtration sedimentation basin characterized in that the water to be treated is filtered by passing through the sand layer.

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