Storage and drainage structure

Abstract

To provide a storage and drainage structure capable of reducing work related to maintenance such as cleaning and suppressing outflow of rainwater to a playground.SOLUTION: A storage and drainage structure 100 according to the present invention comprises: a side ditch 1 that is provided around a playground; a storage tank 2 in which rainwater flowing into the side ditch is collected; a detachable filter 3 for filtering rainwater that is provided on a lower side of the storage tank 2, and divides an internal space of the storage tank 2 into a storage space part 24 and a drainage space part 25 below the storage space part 24 on a horizontal plane perpendicular to a vertical direction; a first drainage part 4 that is provided in the drainage space part 25; and a second drainage part 5 that is provided below the side ditch 1 and above the storage space part 24.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a stored drainage structure. [Background Art]

[0002] Conventionally, in order to drain rainwater and the like falling on general outdoor artificial turf sports fields such as baseball fields, soccer fields, and rugby fields, side ditches are provided around the four periphery of the sports field, and rainwater is collected in these side ditches. The collected rainwater is further collected by one or more water tanks or catch basins, and is discharged out of the sports field through underdrain pipelines. The discharged rainwater may be fed into sewage in combined sewer system areas, but in areas with separate drainage systems, it is directly discharged into rivers and the like via rainwater pipes. In addition, urban sewers are generally designed to accommodate 50 mm of precipitation per hour. However, when local torrential rain caused by weather such as typhoons and torrential downbursts causes rainwater to exceed the treatment capacity of the sewer, it overflows onto the ground surface. The overflowed rainwater becomes overflow water in the form of untreated sewage and is discharged into rivers and sea areas.

[0003] By the way, various sports activities and the like are conducted on artificial turf sports fields. Such activities are not limited to simple walking, and large energy such as sliding may be applied in some cases. Artificial turf is manufactured by planting synthetic resin turf blades to withstand large energy, but when large energy exceeding design standards is applied, or aging occurs due to ultraviolet exposure and the like, the strength of the resin body decreases, and the resin body is cut into fine pieces. In addition, many recent artificial turfs, in order to reduce the burden on the knees of people using the sports field and absorb energy, often adopt a configuration in which fine resin chips are filled at the root of the artificial turf.

[0004] As mentioned above, small fragments of artificial turf, such as broken pieces and chips, flow into drainage ditches with rainwater. However, these ditches are only equipped with gratings (mesh trays) to prevent larger foreign objects from falling in, and are not designed to capture these small fragments. As a result, the generated fragments flow from rivers into the ocean along with other wastewater. In particular, tiny fragments smaller than 5 mm are called microplastics and have recently attracted attention as substances that cause water pollution and have environmental impacts on organisms living in the ocean and rivers. As a device to address such problems, there is a known configuration in which a perforated corrugated pipe is installed inside a drainage ditch, as shown in Patent Document 1, and small pieces of grass material are collected by this corrugated pipe. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-137354 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, conventional drainage structures installed in sports fields such as artificial turf, as shown in Patent Document 1, have the problem that corrugated pipe filtration mesh alone quickly becomes clogged, and when it becomes clogged, rainwater overflows onto the sports field. Furthermore, cleaning the gaps at the bottom of the corrugated pipes was difficult, and there was room for improvement in that respect.

[0007] This invention was made in consideration of these circumstances, and aims to provide a storage and drainage structure that can reduce maintenance work such as cleaning and can suppress the outflow of rainwater into the sports field. [Means for solving the problem]

[0008] To solve the above problems, this invention proposes the following means. A storage and drainage structure according to a first aspect of the present invention comprises: a gutter provided around a sports field; a storage tank from which rainwater flowing into the gutter is collected; a removable filter provided below the storage tank and on a horizontal plane perpendicular to the vertical direction, which divides the internal space of the storage tank into a storage space and a drainage space below the storage space, and filters the rainwater; a first drainage section provided in the drainage space; and a second drainage section provided below the gutter and above the storage space.

[0009] In this invention, when rainwater containing a large amount of small fragments such as resin fragments and chips generated from artificial turf in the early stages of rainfall (first flush) flows into a drainage ditch, it is temporarily stored in a storage space within the ditch, and then slowly filtered and discharged into the sewer system after the rainfall. At this time, the small fragments contained in the rainwater adhere to the filter as they pass through, so they can be easily recovered. Furthermore, there is no need to consider the filtration time, allowing for efficient rainwater treatment, and because the water is gradually discharged into the sewer system while being filtered, the risk of inland flooding can be reduced.

[0010] Furthermore, when recovering small debris that has flowed into the gutter, only the filter needs to be replaced. This reduces the amount of work required for maintenance such as cleaning. Moreover, in this invention, by providing a second drainage section below the gutter and above the storage space, even if rainwater can no longer be drained by the first drainage section of the storage tank, it can be discharged from the second drainage section, preventing rainwater from overflowing from the gutter onto the artificial turf.

[0011] Furthermore, the storage and drainage structure provided around the artificial turf according to the present invention may be configured such that the storage tank has a storage capacity such that, when the rainfall is 50 mm per hour, the water level of the rainwater formed in the storage space of the storage tank after one hour is vertically lower than that of the second drainage section.

[0012] In this case, rainwater can be temporarily stored in the storage area up to the typical drainage capacity of the city (50 mm per hour). Therefore, rainwater can be managed without directly draining the first flush at the beginning of rainfall.

[0013] Furthermore, the storage and drainage structure provided around the artificial turf according to the present invention may have a filter with a pore diameter of less than 5 mm.

[0014] In this case, setting the filter pore size to less than 5 mm allows for more reliable collection of microplastics contained in rainwater.

[0015] Furthermore, the storage and drainage structure provided around the artificial turf according to the present invention may also have a filter made of stainless steel.

[0016] In this case, since stainless steel filters are less prone to rusting, clogging of the filters can be reduced. Furthermore, the amount of maintenance work required, such as cleaning, can be reduced.

[0017] Furthermore, the storage and drainage structure provided around the artificial turf according to the present invention may include a separation unit that further centrifuges the rainwater drained from the first drainage unit and the second drainage unit.

[0018] In this case, by further centrifuging the rainwater discharged from the first and second drainage sections using a centrifugal separator or the like, small particles contained in the rainwater can be removed, thereby preventing water pollution.

[0019] Furthermore, the side ditches of the storage and drainage structure provided around the artificial turf according to the present invention are equipped with a filtration device for filtering the rainwater.

[0020] In this case, the storage and drainage structure can more effectively recover small particles contained in rainwater by using a filtration device installed in the side ditch.

[0021] Also, the side ditch of the storage and drainage structure provided around the artificial turf according to the present invention extends along the inflow and outflow direction in which rainwater flows, and has a bottom part and side parts projecting upward from both sides in the width direction of the bottom part, wherein the filtering device comprises: a cylindrical part with a bottom, which has an opening on the inflow side in the inflow and outflow direction, has a central axis in the inflow and outflow direction, and can arbitrarily change its shape according to the shapes of the bottom part of the side ditch and the inner side surfaces of the side parts; and an inflow-side inner net part, which has a tapered surface extending from the peripheral edge of the opening of the cylindrical part toward the outflow side in the inflow and outflow direction so as to approach the central axis and formed in the circumferential direction of the central axis, and a net opening provided at the end of the tapered surface on the outflow side.

[0022] In this case, the filtering device is provided with a cylindrical part that can arbitrarily deform its shape according to the shapes of the bottom part of the side ditch and the inner side surfaces of the side parts. Therefore, unlike the conventional art, there is no need to custom-make the filtering device according to the shape of the on-site side ditch, and the filtering device can be easily designed. In addition, since the filtering device is provided with a deformable cylindrical part, the number of parts can be reduced compared with conventional filtering devices, and the manufacturing cost can be lowered.

[0023] In addition, in this case, rainwater containing small particulate matters that has flowed into the filtering device from the inflow side in the inflow and outflow direction passes through the net opening, flows into the filtering device, and heads toward the outflow side. However, when rainwater flows backward, it flows to the inflow side instead of the outflow side of the filtering device. Nevertheless, since the inflow side of the filtering device is provided with the inflow-side inner net part having a tapered surface, the filtering device can still properly recover small particulate matters contained in rainwater even in this case.

[0024] Further, the side ditch of the storage and drainage structure provided around the artificial turf according to the present invention extends along the inflow and outflow direction in which rainwater flows, and has a bottom portion and side portions projecting upward from both sides of the bottom portion in the width direction. The filtering device comprises: an outer wall portion formed to match the shapes of the bottom portion of the side ditch and the inner side surfaces of the side portions, the outer wall portion forming a flow channel space inside; a first wall portion formed in the flow channel space, the first wall portion blocking the flow of rainwater within a predetermined range from the lowermost part of the flow channel space upward; and a second wall portion formed in the flow channel space, the second wall portion being located on the outflow side in the inflow and outflow direction relative to the first wall portion and blocking the flow of water within a predetermined range from the uppermost part of the flow channel space downward.

[0025] In this case, the filtering device comprises the first wall portion formed in the flow channel space that blocks the flow of rainwater within a predetermined range from the lowermost part of the flow channel space upward, whereby chips that are as heavy as water or heavier than water among the small piece materials can be suitably recovered.

[0026] Further, in this case, the filtering device further comprises the second wall portion formed in the flow channel space that blocks the flow of water within a predetermined range from the uppermost part of the flow channel space downward on the outflow side in the inflow and outflow direction relative to the first wall portion. Therefore, resin small pieces that are lighter than water among the small piece materials can be suitably recovered.

[0027] Further, a plurality of the first wall portions and the second wall portions of the filtering device according to the present invention are provided alternately.

[0028] In this case, by alternately providing the first wall portions and the second wall portions, the flow of rainwater is slowed down, and the small piece materials can be suitably recovered separately into the resin small pieces and the chips.

[0029] Further, a filter for filtering rainwater is provided at an end portion of the outer wall portion of the filtering device according to the present invention on the outflow side in the inflow and outflow direction.

[0030] In this case, even if small particles that have passed through all the walls are still contained in the rainwater, the filter can catch and stop them. Furthermore, because the filter can remove small particles contained in the rainwater flowing into the gutter, clogging of the filter in the storage tank located downstream of the gutter can be reduced. [Effects of the Invention]

[0031] The storage and drainage structure provided around the artificial turf according to the present invention can reduce maintenance work such as cleaning and suppress the outflow of rainwater onto the sports field. [Brief explanation of the drawing]

[0032] [Figure 1] This is a schematic plan view of a sports field illustrating a storage and drainage structure according to the first embodiment of the present invention. [Figure 2] This is a cross-sectional view along line AA, showing a portion of Figure 1. [Figure 3] This is a perspective view of the storage and drainage structure. [Figure 4] This diagram illustrates an example of the progression of rainwater storage in the storage and drainage structure, showing (a) the initial stage of rainfall, (b) when the storage tank is full, and (c) after rainfall. [Figure 5] This figure shows a modified example of the same storage and drainage structure. [Figure 6] This is a cross-sectional view of a storage and drainage structure according to a second embodiment of the present invention. [Figure 7] Figure 6 is a cross-sectional view along line BB. [Figure 8] (a) is a schematic perspective view of the filtration device. (b) is a schematic perspective view of the filtration device attached to the side ditch of the storage and drainage structure. [Figure 9] This is a perspective view showing the filtration device of the storage and drainage structure according to the third embodiment of the present invention attached to a side ditch. [Figure 10] This is a schematic plan view of the filtration device. [Figure 11] This is a schematic side view of the filtration device. [Figure 12] This diagram illustrates the operation of the filtration device. [Modes for carrying out the invention]

[0033] (First Embodiment) A first embodiment of the present invention will be described with reference to Figures 1 to 4.

[0034] The storage and drainage structure 100 in the first embodiment is installed in a sports field 200 used for sports such as soccer or rugby, as shown in Figure 1. The sports field 200 has a slope from the center outwards to facilitate the flow of rainwater into the side ditch 1, which will be described later. The sports field 200 has a structure in which artificial turf S filled with granular material such as a mixture of sand and rubber chips is laid. Here, small pieces of resin or chips generated from the artificial turf S will be referred to as small pieces F below.

[0035] As shown in Figures 2 and 3, the storage and drainage structure 100 includes a side ditch 1, a storage tank 2, a filter 3, a first drain pipe 4 (first drain section), and a second drain pipe 5 (second drain section).

[0036] The side ditch 1 is buried in the sports field 200, either along a portion or the entire perimeter of the sports field 200, and is made of concrete with a U-shaped cross-section. The side ditch 1 is equipped with a permeable cover 11 on top, such as a concrete or hot-dip galvanized grating. The side ditch 1 has a channel formed in its internal space to drain rainwater towards the storage tank 2, along the perimeter of the sports field 200. The downstream end 12 of the side ditch 1 is connected to the storage tank 2, which is located in one corner of the sports field 200, with a slight downward slope (water gradient) so that rainwater flows into the storage tank 2, as shown in Figure 1. Alternatively, the side ditch 1 may be laid horizontally and then a water gradient may be created within the channel using concrete or other materials. In addition, a manhole or similar structure may be installed between the side ditch 1 and the storage tank 2. In this case, rainwater flowing in from the side ditch 1 will first pass through the manhole or similar structure before flowing into the storage tank 2.

[0037] As shown in Figure 2, the storage tank 2 comprises a lid 21, a bottom 22, and side walls 23, and is buried in a corner of the sports field 200, for example, so that the downstream end 12 of the side ditch 1 is connected to it. The storage tank 2 stores and drains rainwater flowing in from the side ditch 1. The storage tank 2 is preferably made of synthetic resin molded from polypropylene or polyvinyl chloride resin, which has excellent durability and ease of construction, and is formed in a bottomed cylindrical shape with an open top and a closed bottom, as shown in Figures 2 and 3.

[0038] The cover 21 is provided at the upper opening of the storage tank 2 and is a permeable cover made of concrete or a hot-dip galvanized grating, similar to the cover 11 of the side ditch 1. The side wall 23 forms a primary drain hole 231 large enough for the first drain pipe 4 (described later) to pass through, a secondary drain hole 232 large enough for the second drain pipe 5 (described later) to pass through, and an inlet opening 233 above the secondary drain hole 232 through which the downstream end 12 of the side ditch 1 is connected. The primary drain hole 231 is located below the filter 3 (described later), and the secondary drain hole 232 is located above the filter 3. The penetration portions of the primary drain hole 231 and the first drain pipe 4, and the penetration portions of the secondary drain hole 232 and the second drain pipe 5 are fixed by predetermined fixing means, and leakage prevention measures are taken with sealing members made of elastically deformable material (e.g., resin or rubber) to prevent water leakage.

[0039] Furthermore, the side wall 23 has a projection 234 on part or all of the inside of the side wall 23 that protrudes toward the center of the storage tank 2 to a length that allows the outer edge 31 of the filter 3, which will be described later, to be hooked onto it.

[0040] The filter 3 is positioned in the internal space of the storage tank 2 on a horizontal plane perpendicular to the vertical direction, and is formed in a flat plate shape approximately the same size as the rectangular upper opening of the storage tank 2. The filter 3 is made of, for example, stainless steel, and is permeable to water while being able to block the passage of small pieces F containing microplastics of 5 mm or less contained in rainwater. The filter 3 also has numerous holes 32 spaced at equal intervals of less than 5 mm, except for the outer edge 31. Furthermore, the filter 3 is inserted from the upper opening of the storage tank 2 and is detachably attached by hooking onto a projection 234 formed on the side wall 23. The filter 3 divides the internal space of the storage tank 2 into an upper storage space 24 and a lower drainage space 25. Here, the height position of the filter 3 should be set so that the storage space 24 is larger than the drainage space 25 in order to increase the storage capacity of the storage tank 2.

[0041] As shown in Figure 2, the first drain pipe 4 (first drain section) has a base opening 4a at its base end and a tip opening 4b at its tip. The base opening 4a of the first drain pipe 4 communicates with the primary drain hole 231 of the drain space 25, allowing rainwater that has passed through the filter 3 in the storage tank 2 to be drained. A grating cover is also provided at the base opening 4a.

[0042] As shown in Figure 2, the second drain pipe 5 (second drain section) has a base opening 5a at its base end and a tip opening 5b at its tip. The base opening 5a of the second drain pipe 5 is connected to the secondary drain hole 232 of the storage space 24, allowing rainwater that does not pass through the filter 3 stored in the storage tank 2 to be drained. A grating cover is also provided at the base opening 5a.

[0043] As shown in Figure 2, the storage and drainage structure 100 is further equipped with a centrifugal separator 6 (centrifugal separator). The centrifugal separator 6 has the function of generating centrifugal force by, for example, rotating the rainwater, separating the small fragments F contained in the rainwater, and draining only the rainwater from which the separated small fragments F have been removed. The centrifugal separator 6 is installed at the tip opening 4b of the first drain pipe 4 and the tip opening 5b of the second drain pipe 5, respectively. Therefore, rainwater flowing through the tip opening 4b can be drained into the main sewer pipe (not shown) after the small fragments F that have passed through the filter 3 are centrifuged by the centrifugal separator 6. Rainwater flowing through the tip opening 5b is discharged without passing through the filter 3, but can be drained into the main sewer pipe (not shown) after the small fragments F have been separated by the centrifugal separator 6. Note that one centrifugal separator 6 may be used, provided that it has the processing capacity to handle rainwater drained from both the first drain pipe 4 and the second drain pipe 5. The number of centrifugal separators 6 is not limited and is selected appropriately according to the processing capacity.

[0044] In this embodiment, as shown in Figure 4, the storage space 24 of the storage and drainage structure 100 has a storage capacity that can store rainwater collected in the first hour of rainfall when the rainfall rate is 50 mm per hour. At that time, the storage tank 2 is assumed to be full, and the water level formed in the storage tank 2 is defined as QM. The lowest part 5k of the second drain pipe 5 is set at approximately the same height as the water level QM.

[0045] Next, the operation of the storage and drainage structure 100 according to the first embodiment will be explained with reference to Figure 4.

[0046] As shown in Figure 4(a) during the initial stages of rainfall, rainwater that falls on the sports field 200 (see Figure 1) flows into the gutter 1 due to the slope provided in the sports field 200, flows through the channel formed in the internal space of the gutter 1, and is collected in the storage tank 2. The sports field 200 has a slope from the center outwards to facilitate the flow of rainwater into the gutter 1. Therefore, the rainwater is reliably guided into the gutter 1. The rainwater collected in the gutter 1 flows down a slight slope to the storage tank 2 located in one corner of the sports field 200, and is stored in the storage space 24.

[0047] The storage and drainage structure 100 is equipped with a storage space 24, and does not directly drain rainwater containing a large amount of small materials such as resin fragments and chips, as well as microplastics (first flush) in the initial stages of rainfall from the side ditch 1, but temporarily stores it in the storage space 24. Subsequently, the stored rainwater in the initial stages of rainfall is filtered by a filter 3 installed in the storage tank 2 over time, and then drained from the base end opening 4a of the first drain pipe 4. Therefore, the storage and drainage structure 100 does not directly drain the first flush in the initial stages of rainfall. In addition, in this case, the storage and drainage structure 100 temporarily stores the collected rainwater in the storage tank 2 while filtering it with the filter 3, thus reducing the risk of small fragments F clogging the side ditch 1 and causing rainwater to overflow outside the sports field 200. Furthermore, the storage and drainage structure 100 can efficiently process rainwater without having to consider the time required for filtration by the filter 3.

[0048] Next, as shown in Figure 4(b), when the storage tank 2 is full, a water surface QM is formed inside the storage tank 2. Here, the storage tank 2 has the storage capacity to store rainwater collected in the first hour or so of rainfall when the rainfall rate is 50 mm per hour, and at that time the storage tank 2 is full. The rainwater stored in the storage tank 2 is filtered by the filter 3 over time and discharged from the base end opening 4a of the first drain pipe 4. Even in this case, the storage and drainage structure 100 can process the small fragments F contained in the rainwater without directly draining them, as the small fragments F are recovered by the filter 3 installed inside the storage tank 2. Subsequently, in Figure 4(b), if rain continues from the middle to the later stages of rainfall, the incoming rainwater will exceed the storage capacity of the storage space 24. However, when the water level formed by the stored rainwater exceeds the water level QM, the rainwater is drained into the second drainage pipe 5, so the rainwater can be drained without overflowing from the storage tank 2. Therefore, the storage and drainage structure 100 can drain rainwater without it flowing outside the sports field 200. Furthermore, even in the case of torrential rainfall exceeding 50 mm per hour in the initial stages of rainfall, the second drainage pipe 5 installed inside the storage tank 2 will similarly drain the rainwater that exceeds its storage capacity, so the rainwater will be stored and drained without overflowing outside the sports field 200.

[0049] As shown in Figure 4(c), after rainfall, the rainwater stored in the storage space 24 is gradually filtered by a filter 3 installed inside the storage tank 2. At this time, the filter 3 has numerous holes 32 spaced at equal intervals of less than 5 mm in the portion excluding the outer edge 31. Therefore, when the stored rainwater is filtered by the filter 3, it is possible to prevent the passage of small pieces F containing microplastics of 5 mm or less contained in the rainwater.

[0050] In this embodiment, as shown in Figure 4, centrifugal separators 6 are provided at the tip opening 4b of the first drain pipe 4 and at the tip opening 5b of the second drain pipe 5. By installing the centrifugal separator 6 at the tip opening 4b of the first drain pipe 4, rainwater containing small fragments F that have passed through the filter 3 is further centrifuged, allowing only the rainwater from which the small fragments F have been removed to be discharged into the main sewer pipe (not shown). Furthermore, by installing the centrifugal separator 6 at the tip opening 5b of the second drain pipe 5, even if rainwater exceeding the storage capacity of the storage tank 2 is discharged from the second drain pipe 5 without passing through the filter 3, the centrifugal separator 6 will centrifuge the rainwater into small fragments F, allowing only the rainwater from which the small fragments F have been removed to be discharged into the main sewer pipe (not shown).

[0051] In this embodiment, compared to filtering all wastewater from the beginning to the end of rainfall, it is possible to efficiently and reliably treat wastewater from the beginning of rainfall.

[0052] Furthermore, in this embodiment, since the filter 3 installed in the internal space of the storage tank 2 is removable, after the small fragments F that have flowed in can be recovered, the filter 3 can be easily removed and maintenance work such as cleaning can be performed.

[0053] As described above, the storage and drainage structure 100 according to this embodiment can reduce maintenance work such as cleaning and can suppress the outflow of rainwater into the sports field 200.

[0054] (modified version) A modified version of the first embodiment will now be described. For example, as shown in Figure 5, the storage and drainage structure 100A stores and drains water by equipping a storage tank 2A, which is a modified version of the storage tank 2, with a ball tap B, which is used in flush toilets and water receiving tanks. The ball tap B has a float ball B2 connected to one end of a support rod B1 and a shut-off valve B3 connected to the other end. The float ball B2 is located on the water surface QA in the storage tank 2A ​​and changes the angle of the support rod B1 according to the height of the water surface QA. As the angle of the support rod B1 changes, the opening degree of the shut-off valve B3 changes, and the shut-off valve B3 is configured to close when the water surface QA reaches a predetermined height, so that no more drainage flows into the storage tank 2A.

[0055] The storage and drainage structure 100A further includes a pipe 7 connecting the side ditch 1 and the storage tank 2A. The pipe 7 has a first main pipe 71 with one end connected to the side ditch 1 and extending vertically downward, a second main pipe 72 with one end connected to the other end of the first main pipe 71 and extending substantially horizontally vertically above the storage tank 2A, and a branch pipe 73 with one end connected to the middle of the second main pipe 72. The other end of the branch pipe 73 is connected to the storage tank 2A, forming a tank outlet 7a. The other end of the second main pipe 72 guides in the direction of the main sewer pipe (not shown), forming a sewer outlet 7b. The second main pipe 72 is bent upward on the sewer outlet 7b side of the connected branch pipe 73, and the sewer outlet 7b is provided above the tank outlet 7a and below the side ditch 1. This configuration ensures that rainwater in the initial stages of rainfall flows first to the tank outlet 7a. The second main pipe 72 does not necessarily have to be bent. The second main pipe 72 may be configured to flow to the tank outlet 7a by, for example, having a slope that is inclined toward the tank outlet 7a. Alternatively, the route of the pipe 7 may be arbitrarily changed to ensure that it flows to the tank outlet 7a. A shut-off valve B3 is provided at the tank outlet 7a. The shut-off valve B3 opens from a state where the float ball B2, supported by the support rod B1, is not floating on the water surface QA, until the water level rises below a predetermined height due to the inflow of rainwater, and then closes when the water level reaches the predetermined height.

[0056] Next, the operation of the storage and drainage structure 100A will be explained. In the early stages of rainfall, rainwater drained from the tank outlet 7a is stored in the storage tank 2A ​​and filtered by the filter 3. As rainfall progresses into the later stages, rainwater accumulates in the storage tank 2A, and when the float ball B2 rises to a predetermined height due to the water level rise, the shut-off valve B3 closes, stopping the inflow of rainwater into the storage tank 2A. When the shut-off valve B3 is closed, the rainwater flows along the flow path of the second main pipe 72 to the sewer outlet 7b at the other end and is drained into the main sewer pipe. When the rainwater stored in the storage tank 2A ​​is filtered and the water level in the storage tank 2A ​​drops, the shut-off valve B3 opens again, and rainwater flows into the storage tank 2A.

[0057] Even in this case, the storage and drainage structure 100A can store and reliably treat rainwater during normal rainfall and torrential downpours without directly draining the first flush at the beginning of the rainfall.

[0058] Furthermore, for example, the storage and drainage structure 100 of this embodiment may have a function to collect small fragments on the side of the gutter 1 into which rainwater flows, in addition to the filter 3 in the storage tank 2. For example, the gutter 1 may be further equipped with a small fragment collection material having a number of pore sizes, such as a mesh or filter, that can collect small fragments F. Alternatively, the gutter 1 may be laid with fine sand at the bottom and equipped with fine sand and a permeable drainage pipe that can drain only rainwater that has passed through the fine sand. In this case, small fragments F can be collected in the process of passing through the small fragment collection material or fine sand provided in the gutter 1 before the rainwater flowing in from the sports field 200 is collected in the storage tank 2, thereby preventing water pollution of the rainwater discharged into the sewer. In addition, the filtration treatment time in the storage tank 2 can be reduced.

[0059] For example, the storage and drainage structure 100 may have an infiltration function in the side ditch 1 or storage tank 2. By providing an infiltration function in the side ditch 1 or storage tank 2, the incoming rainwater can infiltrate into the ground within the storage and drainage structure 100 before being drained, thereby reducing the amount of rainwater that is discharged into the sewer system. Furthermore, even if small fragments F are mixed in with the rainwater that has infiltrated into the ground, the small fragments F will remain in the ground, preventing them from flowing out of the site.

[0060] For example, the side ditch 1 of the storage and drainage structure 100 in this embodiment is intended for a typical U-shaped ditch, but it is not limited to U-shaped ditches.

[0061] The first drain pipe in this embodiment does not necessarily have to be on the side. For example, it may be provided at the bottom 22 so as to allow rainwater accumulating in the drainage space to be drained.

[0062] Furthermore, in this embodiment, the filter 3 is placed inside the storage tank 2 by hooking it onto the protrusion 234 of the storage tank 2, but the means of placement are not limited to this. For example, it may be placed by tying it to the storage tank 2 with a string or the like. In either case, it is detachable, so the work involved in maintenance such as cleaning can be reduced. In addition, by providing multiple protrusions 234 in the vertical direction and changing the height of the filter 3, the size of the storage space 24 of the storage tank 2 can be changed. Therefore, the storage capacity can be easily changed in different environments without having to consider complex designs.

[0063] Furthermore, the storage and drainage structure 100 of this embodiment may also include a third drainage pipe in the drainage space 25 of the storage tank 2, a second storage section at approximately the same height as the underground storage tank 2 at the end of the flow path formed by the piping, and a pump and a fourth drainage pipe connecting the pump to the surface within the second storage section. Rainwater flowing into the drainage space 25 is filtered by a filter 3 installed above the drainage space 25. As a result, some of the rainwater flows from the storage tank 2 through the third drainage pipe into the second storage section, and the rainwater stored in the second storage section can be pumped up to the surface and effectively used for various purposes such as watering plants and washing cars.

[0064] Furthermore, filter 3 is not limited to being made of stainless steel; other materials such as metal or synthetic resin can also be used.

[0065] Furthermore, the shape, length, dimensions, and other configurations of the storage and drainage structure 100 can be appropriately set considering the applicable drainage capacity. In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of the present invention.

[0066] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 6 to 8. In the following description, components that are common to those already described will be denoted by the same reference numerals, and redundant descriptions will be omitted. Note that the following embodiments all differ from the first embodiment in their storage and drainage structure. Therefore, the following description will focus on the differences from the first embodiment.

[0067] Figure 6 is a cross-sectional view of the storage and drainage structure 100B according to the second embodiment of the present invention. Figure 7 is a cross-sectional view taken along line BB in Figure 6. As shown in Figure 6, the storage and drainage structure 100B includes a filtration device 8 in addition to the side ditch 1, storage tank 2, filter 3, first drain pipe 4, and second drain pipe 5 that are present in the storage and drainage structure 100 according to the first embodiment.

[0068] Here, we will explain the specific configuration of the drainage ditch 1. Rainwater flows through the gutter 1 from the side opposite the storage tank 2 towards the side facing the storage tank 2. In the following description, the direction in which rainwater flows will be referred to as the flow direction (inflow / outflow direction) R. In the flow direction R, the direction in which rainwater flows into the gutter 1 will be referred to as the inflow side R1. Also, the direction in which rainwater flows out of the gutter 1 toward the storage tank 2 will be referred to as the outflow side R2. Furthermore, the width direction of the gutter 1 perpendicular to the vertical direction and the flow direction R will be referred to as the width direction W. In the width direction W, one side will be referred to as the left side W1 and the other side as the right side W2. Although not particularly limited, in this embodiment, the plane formed by the flow direction R and the width direction W is a horizontal plane.

[0069] As shown in Figure 7, the side ditch 1 is formed in a U-shape with a recessed lower side when viewed from the water flow direction R, as described above. The side ditch 1 extends along the water flow direction R. The side ditch 1 comprises a bottom portion 1d and side portions 1b and 1c that protrude upward from both sides in the width direction W of the bottom portion 1d. The side ditch 1 has inner surfaces 1a on the bottom portion 1d and the side portions 1b and 1c.

[0070] [Filtering device 8] Figure 8(a) is a schematic perspective view of the filtration device 8. Figure 8(b) is a schematic perspective view of the filtration device 8 attached to the side ditch 1. As shown in Figure 6, the filtration device 8 is installed in a part of the side ditch 1. The filtration device 8 can be arbitrarily reshaped to match the shape of the side ditch 1 and filters rainwater flowing in the direction of flow R. The filtration device 8 comprises a cylindrical part 81 and an inlet-side inner mesh part 82.

[0071] As shown in Figure 8(a), the cylindrical portion 81 is formed as a bottomed cylindrical shape with a central axis O1 passing through the water flow direction R as its central axis. The cylindrical portion 81 is approximately circular when viewed from the water flow direction. The cylindrical portion 81 is formed, for example, from mesh, and collects small pieces F while allowing water to pass through. Specifically, the cylindrical portion 81 is formed as a bottomed cylindrical shape using stainless steel mesh and wire (framework). The cylindrical portion 81 can be arbitrarily deformed to match the shape of the bottom 1d and the inner surfaces 1a of the sides 1b and 1c of the side ditch 1. The cylindrical portion 81 has an opening 81a on the inflow side R1. The cylindrical portion 81 also includes a bottom plate portion 810 and a side plate portion 811.

[0072] The bottom plate portion 810 is the bottom of the side ditch 1. The side plate portion 811 extends from the periphery of the bottom plate portion 810 toward the inflow side R1 and is formed in the circumferential direction of the central axis O1. The side plate portion 811 has an inner surface 811a facing the central axis O1 of the cylindrical portion 81.

[0073] The inlet-side inner mesh section 82 is provided at the opening 81a of the cylindrical section 81. The inlet-side inner mesh section 82, like the cylindrical section 81, is formed of, for example, stainless steel mesh, and collects small pieces F while allowing water to pass through. The inlet-side inner mesh section 82 is formed in a bottomless cylindrical shape with a central axis O1 as its central axis. The inlet-side inner mesh section 82 has a tapered surface 820 that extends circumferentially from the periphery of the opening 81a toward the outlet side R2, approaching the central axis O1. The inlet-side inner mesh section 82 also has a mesh opening 82a at the outlet side R2 end of the tapered surface 820.

[0074] Next, the operation of the storage and drainage structure 100B according to the second embodiment will be explained with reference to Figure 8.

[0075] The filtration device 8 can be arbitrarily reshaped to match the shape of the gutter 1. As shown in Figures 8(a) and 8(b), the bottomed cylindrical shape of the cylindrical portion 81 of the filtration device 8 can be matched to the shape of the inner surface 1a of the gutter 1. For example, the filtration device 8 is formed in a roughly rectangular prism shape with the flow direction R as its longitudinal axis, so that it is roughly rectangular when viewed from the flow direction R (see Figure 7). Specifically, the filtration device 8 obtains the above shape by placing a heavy object J such as a brick from above at an arbitrary position on the inner surface 811a of the side plate portion 811 of the cylindrical portion 81, and bringing the side plate portion 811 into contact with the inner surface 1a of the gutter 1 to deform it. The inlet side inner mesh portion 82 of the filtration device 8 may be deformed to match the cylindrical portion 81, or it may maintain its original shape. Furthermore, the filtration device 8 may be adapted to the shape of the inner surface 1a of the gutter 1 by deforming the side plate portion 811 of the cylindrical portion 81 by the operator's hand, or it may be adapted to the shape of the inner surface 1a of the gutter 1 in any other direction.

[0076] Rainwater flowing into the filtration device 8, which is deformed to match the shape of the side ditch 1, enters through the opening 81a and passes through the mesh opening 82a. The rainwater then passes through the mesh of the bottom plate 810 and flows towards the storage tank 2. At this time, small fragments F contained in the rainwater get caught on the bottom plate 810 and accumulate. With this configuration, the filtration device 8 can filter the rainwater.

[0077] In this embodiment, the storage and drainage structure 100B is provided in the side ditch 1 and includes a filtration device 8 that filters rainwater flowing in the direction of water flow R. Therefore, the storage and drainage structure 100B can more effectively recover small fragments F contained in the rainwater by the filtration device 8.

[0078] Furthermore, in this embodiment, the filtration device 8 is equipped with a cylindrical portion whose shape can be arbitrarily changed to match the shape of the bottom 1d and the inner surfaces 1a of the sides 1b and 1c of the side ditch 1. Therefore, unlike in the past, there is no need to custom-make the filtration device 8 to match the shape of the side ditch on site, and the filtration device 8 can be easily designed. In addition, because the filtration device 8 is equipped with a deformable cylindrical portion, the number of parts can be reduced compared to conventional filtration devices, and manufacturing costs can be reduced.

[0079] Furthermore, in this embodiment, the inlet-side inner mesh portion 82 is provided with a tapered surface 820 extending circumferentially from the periphery of the opening 81a of the cylindrical portion 81 toward the outlet-side R2 so as to approach the central axis O1. Rainwater containing small pieces F that flows into the filtration device 8 from the inlet-side R1 in the flow direction R passes through the mesh portion opening 82a and flows into the interior of the filtration device 8, heading toward the bottom plate portion 810 on the outlet-side R2. However, if the rainwater flows backward, it will flow toward the inlet-side R1 of the filtration device 8 instead of the outlet-side R2. However, since the inlet-side inner mesh portion 82 with the tapered surface 820 is provided on the inlet-side R1 of the filtration device 8, the filtration device 8 can still effectively recover the small pieces F contained in the rainwater in this case as well.

[0080] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Figures 9 and 12. In the following description, components common to those already described will be denoted by the same reference numerals, and redundant descriptions will be omitted. Note that the following embodiments differ from the second embodiment in their filtration apparatus. Therefore, the following description will focus on the differences from the second embodiment.

[0081] Figure 9 is a perspective view showing the filtration device 8C of the storage and drainage structure 100C according to the third embodiment of the present invention attached to the side ditch 1. For the sake of explanation, the cover 11 provided on the side ditch 1 is omitted from the illustration in Figure 9. The storage and drainage structure 100C includes a filtration device 8C that is different from the filtration device 8 according to the second embodiment.

[0082] The filtration device 8C comprises a bottom plate 81C, a left side plate 82C, a right side plate 83C, a wall 84C, and a filter 85C. The bottom plate 81C, the left side plate 82C, and the right side plate 83C form the outer wall of the filtration device 8C. The filtration device 8C also forms a flow path through which rainwater flows from the opening 8Cp formed by the bottom plate 81C, the left side plate 82C, and the right side plate 83C toward the internal space (flow path space) 8Ca. The outer wall of the filtration device 8C is formed in a U-shape (or U-shape) in cross-section to match the shape of the side ditch 1.

[0083] The bottom plate portion 81C is the bottom of the filtration device 8C. The bottom plate portion 81C is formed in a rectangular shape with two sides facing each other in the water flow direction R and the width direction W. The bottom plate portion 81C is formed along the horizontal plane, in contact with the bottom 1d of the side ditch 1.

[0084] The left side plate portion 82C is the left side W1 in the width direction W of the filtration device 8C. The left side plate portion 82C is erected upward from one side of the left side W1 in the width direction W of the bottom plate portion 81C. The left side plate portion 82C is formed in a rectangular shape with two sides facing each other in the water flow direction R and the vertical direction, respectively. The left side plate portion 82C abuts against the side portion 1b of the side ditch 1. The vertical height of the left side plate portion 82C is not particularly limited, but is slightly lower than the height of the side portion 1b of the side ditch 1.

[0085] The right-side plate portion 83C is the right side W2 in the width direction W of the filtration device 8C. The right-side plate portion 83C is erected upward from one side of the right side W2 in the width direction W of the bottom plate portion 81C. The right-side plate portion 83C is formed in a rectangular shape with two sides facing each other in the water flow direction R and the vertical direction, respectively. The right-side plate portion 83C abuts against the side portion 1c of the side ditch 1. In this embodiment, the vertical height of the right-side plate portion 83C is about the same as that of the left-side plate portion 82C.

[0086] Figure 10 is a schematic plan view of the filtration device 8C. Figure 11 is a schematic side view of the filtration device 8C. As shown in Figures 10 and 11, the wall portion 84C is provided in the internal space 8Ca of the filtration device 8C. Multiple wall portions 84C are provided, and in this embodiment, they include a first wall portion 841C, a second wall portion 842C, a third wall portion 843C, and a fourth wall portion 844C.

[0087] The first wall portion 841C is formed in a rectangular shape with two sides facing each other in the width direction W and the vertical direction. The first wall portion 841C is located on the inflow side R1 of the center of the bottom plate portion 81C in the water flow direction R. The first wall portion 841C is erected above the bottom plate portion 81C, which is the lowest part of the internal space 8Ca. In this embodiment, the height of the first wall portion 841C is about half the height of the left plate portion 82C and the right plate portion 83C. The first wall portion 841C is in close contact with the bottom plate portion 81C, the left plate portion 82C and the right plate portion 83C. In the vertical direction, the first wall portion 841C restricts the flow of rainwater in a predetermined range from the bottom plate portion 81C upwards to half the height of the left plate portion 82C and the right plate portion 83C.

[0088] The second wall portion 842C is formed in a rectangular shape with two sides facing each other in the width direction W and the vertical direction, respectively. The second wall portion 842C is located on the outflow side R2 of the first wall portion 841C in the water flow direction R. Here, the surface connecting the uppermost part of the left plate portion 82C and the uppermost part of the right plate portion 83C is the uppermost part of the internal space 8Ca. The second wall portion 842C is in close contact with the left plate portion 82C and the right plate portion 83C and extends downward from the uppermost part of the internal space 8Ca. The second wall portion 842C provides a gap 842Cs between itself and the bottom plate portion 81C. In this embodiment, the height of the gap 842Cs is from the upper surface of the bottom plate portion 81C to half the height of the first wall portion 841C in the vertical direction. In other words, the upper half of the first wall portion 841C overlaps with the second wall portion 842C when viewed from the water flow direction R. Furthermore, the second wall section 842C restricts the flow of rainwater in a predetermined range in the vertical direction, from the top of the internal space 8Ca downwards to half the height of the first wall section 841C.

[0089] The third wall section (first wall section) 843C is formed in substantially the same shape as the first wall section 841C. The third wall section 843C is located on the outflow side R2 of the second wall section 842C in the water flow direction R. The third wall section 843C is erected upward from the bottom plate section 81C, which is the lowest part of the internal space 8Ca. In this embodiment, the height of the third wall section 843C is approximately the same as that of the first wall section 841C. The third wall section 843C is in close contact with the bottom plate section 81C, the left side plate section 82C, and the right side plate section 83C, and in the vertical direction, it restricts the flow of rainwater in a predetermined range from the bottom plate section 81C upwards to half the height of the left side plate section 82C and the right side plate section 83C.

[0090] The fourth wall (second wall) 844C is formed in substantially the same shape as the second wall 842C. The fourth wall 844C is located on the outflow side R2 of the third wall 843C in the water flow direction R. The fourth wall 844C is in close contact with the left plate 82C and the right plate 83C and extends downward from the top of the internal space 8Ca. The fourth wall 844C provides a gap 844Cs between itself and the bottom plate 81C. In this embodiment, the height of the gap 844Cs is from the top surface of the bottom plate 81C to half the height of the third wall 843C in the vertical direction. In other words, the upper half of the third wall 843C, as viewed from the water flow direction R, overlaps with the fourth wall 844C. Furthermore, the fourth wall section 844C restricts the flow of rainwater in a predetermined range in the vertical direction, from the top of the internal space 8Ca downwards to half the height of the third wall section 843C.

[0091] The third wall section 843C is the same size and shape as the first wall section 841C, and is therefore also called the first wall section. The fourth wall section 844C is the same size and shape as the second wall section 842C, and is therefore also called the second wall section. The first wall section 841C, the second wall section 842C, the third wall section 843C, and the fourth wall section 844C are arranged in this order in the internal space 8Ca, from the inflow side R1 to the outflow side R2 in the flow direction R. In other words, multiple first and second wall sections are provided alternately.

[0092] Here, in the direction of water flow R, the space from the opening 8Cp of the filtration device 8C to the first wall portion 841C within the internal space 8Ca is defined as the first space 8Caa. The space from the first wall portion 841C to the second wall portion 842C is defined as the second space 8Cab. The space from the second wall portion 842C to the third wall portion 843C is defined as the third space 8Cac. The space from the third wall portion 843C to the fourth wall portion 844C is defined as the fourth space 8Cad. Furthermore, the space from the fourth wall portion 844C to the filter 85C described later is defined as the fifth space 8Cae.

[0093] The filter 85C is provided to cover the outlet side R2 end of the filtration device 8C. Specifically, the periphery of the filter 85C is attached to the respective outlet side R2 ends of the bottom plate portion 81C, the left plate portion 82C, and the right plate portion 83C. The filter 85C is provided further out on the outlet side R2 than the wall portion 84C. The filter 85C is made of, for example, stainless steel and is permeable to water while preventing the passage of small pieces F containing microplastics of 5 mm or less contained in rainwater.

[0094] Next, the operation of the storage and drainage structure 100C according to the third embodiment will be explained with reference to Figure 12. Figure 12 is a diagram illustrating the operation of the filtration device 8C.

[0095] Here, the small fragments F are small pieces of material such as resin fragments and chips generated from the artificial turf S. In other words, the small fragments F are composed of resin fragments F1 and chips F2. The chips F2 are filled into the base of the artificial turf, and after the small fragments F are collected, the chips F2 are again filled into the base of the artificial turf as a filler. Therefore, after collecting the small fragments F, the worker needs to separate them into resin fragments F1 and chips F2.

[0096] Rainwater flowing into the filtration device 8C enters the filtration device 8C through the opening 8Cp. First, the rainwater flows into the first space 8Caa within the internal space 8Ca.

[0097] The rainwater contains small pieces F, which are resin pieces F1 and chips F2. The resin pieces F1 are small pieces of resin from the artificial turf, so they are lighter than water and float on the rainwater. The chips F2 are rubber chips or the like that filled into the base of the artificial turf, and are about the same weight as or heavier than water, so they sink easily. Therefore, the chips F2 sink in the rainwater and flow along with it. When the rainwater moves from the first space 8Caa to the second space 8Cab on the outflow side R2, the chips F2 that are submerged in the rainwater get caught on the first wall 841C and accumulate, as shown in Figure 12.

[0098] Since the resin fragments F1 float on the rainwater, if the amount of rainwater exceeds the first wall portion 841C, they move into the second space 8Cab along with the rainwater without getting caught on the first wall portion 841C.

[0099] Rainwater moves from the second space 8Cab to the third space 8Cac on the outflow side R2. At this time, the resin pieces F1, which float on the rainwater, get caught on the second wall 842C and accumulate as the rainwater moves from the second space 8Cab to the third space 8Cac on the outflow side R2. In addition, a gap 842Cs is formed in the second wall 842C that separates the second space 8Cab and the third space 8Cac. Therefore, rainwater moves to the third space 8Cac through the gap 842Cs.

[0100] Rainwater is gradually accumulated in the third space 8Cac. Chips F2 contained in the rainwater that do not get caught in the first wall 841C tend to accumulate at the bottom of the third space 8Cac. When the amount of rainwater exceeds the height of the third wall 843C, it overflows and moves into the fourth space 8Cad. At this time, the upper part of the rainwater always flows into the fourth space 8Cad, so the chips F2 that are submerged in the rainwater remain in the third wall 843C and accumulate.

[0101] Rainwater that flows into the fourth space 8Cad then moves through the gaps 844Cs in the fourth wall 844C to the fifth space 8Cae. At this time, the resin fragments F1 that float on the rainwater get caught on the fourth wall 844C and accumulate as the rainwater moves from the fourth space 8Cad to the fifth space 8Cae on the outflow side R2.

[0102] In the fifth space 8Cae, a filter 85C is provided on the outflow side R2. Therefore, even if small fragments F that have passed through all the wall sections 84C are still contained in the rainwater, the filter 85C will catch and stop the fragments F. With this configuration, the rainwater passing through the filtration device 8C is filtered and flows out into the storage tank 2.

[0103] In this embodiment, the filtration device 8C includes a first wall portion 841C that restricts the flow of rainwater in a predetermined range from the bottom plate portion 81C upwards to half the height of the left plate portion 82C and the right plate portion 83C, and a second wall portion 842C that restricts the flow of rainwater in a predetermined range from the top of the internal space 8Ca downwards to half the height of the first wall portion 841C. Therefore, the filtration device 8C can suitably recover chips F2, which are small pieces F that are filled at the base of the artificial turf and are about the same weight as or heavier than water, by the first wall portion 841C.

[0104] Furthermore, the filtration device 8C can suitably recover resin fragments F1 that are lighter than water from among the small fragments F, thanks to the second wall portion 842C.

[0105] Furthermore, in this embodiment, the first wall section 841C, the second wall section 842C, the third wall section 843C, and the fourth wall section 844C are arranged in this order in the internal space 8Ca from the inflow side R1 to the outflow side R2 in the water flow direction R, and multiple first and second wall sections are provided alternately. As a result, the filtration device 8C can smoothly slow down the flow of rainwater by alternating the first and second wall sections, and can suitably separate and recover small fragments F into resin fragments F1 and chips F2. In addition, by providing multiple sections, even if small fragments F pass through one wall section, they can be stopped by the next wall section, thereby reducing the probability that small fragments will be included in the rainwater.

[0106] Furthermore, in this embodiment, the resin fragments F1 and chips F2 can be easily separated. Therefore, the worker can reduce the work that was previously performed to extract the chips F2 from the fragments F in order to refill the base of the artificial turf. In addition, this allows the filtration device 8C to improve work efficiency.

[0107] Furthermore, in this embodiment, the filtration device 8 is equipped with a filter 85C for filtering rainwater. Specifically, the filter 85C has its periphery attached to the ends of the outflow side R2 of the bottom plate portion 81C, the left plate portion 82C, and the right plate portion 83C. Therefore, even if small pieces F that have passed through all the wall portions 84C are still contained in the rainwater, the filter 85C will catch and stop the small pieces F. In addition, since the filtration device 8 can remove small pieces F contained in the rainwater flowing into the gutter 1 by the wall portions 84C and the filter 85C, clogging of the filter 3 of the storage tank 2, which is located on the outflow side R2 downstream of the gutter 1, can be reduced.

[0108] The overall size and length of the filtration apparatus according to the second and third embodiments described above are not particularly limited. Furthermore, the shape of the filtration apparatus is not particularly limited, and only one example is shown in this embodiment.

[0109] Furthermore, the range in which the flow of rainwater is stopped in the first wall portion 841C, the second wall portion 842C, the third wall portion 843C, and the fourth wall portion 844C according to the above embodiment is not particularly limited, and any predetermined range can be set.

[0110] Furthermore, in the storage and drainage structure 100 of this embodiment, for example, if the weather forecast predicts only a small amount of rainfall, a means may be provided to store water in the sports field 200 in advance using a predetermined method.

[0111] Specifically, for example, in the case of light rainfall of about 10 mm per hour, surface flow does not usually occur on the sports field. To intentionally generate this surface flow, a means is provided to manually or automatically store water in the sports field 200 in advance. With this configuration, surface flow occurs when light rainfall occurs. At this time, the first flush flows into the drainage ditch, and microplastics can be suitably recovered by the filtration device installed in the drainage ditch. Furthermore, by setting the pore size of the stainless steel mesh used in the filtration device to, for example, less than 0.1 mm, it is also possible to recover fine microplastics of about 0.1 mm, which are particularly abundant in the first flush.

[0112] It should be noted that the present invention is not limited by the embodiments described above. Furthermore, the components in the embodiments described above include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the components disclosed in the embodiments described above can be combined as appropriate. [Explanation of Symbols]

[0113] 100, 100A Storage and Drainage Structure 1. Side ditch 2, 2A storage tank 24 Storage Space 25 Drainage space 3 filters 4 First drain pipe (first drain section) 5 Second drain pipe (second drain section) 6. Centrifugal separator (centrifugal section) 8, 8C filtration device 81 Cylindrical part 82 Inlet side mesh section 8Ca internal space 81C Bottom plate part 82C Left side plate 83C Right side plate 84C wall 841C First wall section 842C Second wall section 843C Third wall 844C Fourth wall 85C filter 200 playground S Artificial grass QM water surface F small piece F1 Resin Pieces F2 Chip

Claims

1. The drainage ditches provided around the sports field, A storage tank from which rainwater that flows into the aforementioned side ditch is collected, A removable filter is provided on the lower side of the storage tank, on a horizontal plane perpendicular to the vertical direction, which divides the internal space of the storage tank into a storage space and a drainage space below the storage space, for filtering rainwater. The first drainage section provided in the drainage space, A second drainage section is provided below the aforementioned side ditch and above the aforementioned storage space, Equipped with, The aforementioned drainage ditch is equipped with a filtration device for filtering rainwater. The aforementioned side ditch extends along the inflow and outflow direction of rainwater flow, and has a bottom portion and side portions that protrude upward from both sides of the bottom portion in the width direction. The aforementioned filtration device is A cylindrical part having an opening on the inflow side in the aforementioned inflow / outflow direction, a bottomed cylindrical shape with a central axis in the aforementioned inflow / outflow direction, and whose shape can be arbitrarily changed to match the shape of the inner surface of the bottom and side of the side ditch, An inlet-side inner mesh portion having a tapered surface that extends from the periphery of the opening of the cylindrical portion toward the outflow side in the inflow / outflow direction so as to approach the central axis and is formed in the circumferential direction of the central axis, and a mesh portion opening provided at the outflow-side end of the tapered surface, A storage and drainage structure equipped with [a specific feature].

2. The drainage ditches provided around the sports field, A storage tank from which rainwater that flows into the aforementioned side ditch is collected, A removable filter is provided on the lower side of the storage tank, on a horizontal plane perpendicular to the vertical direction, which divides the internal space of the storage tank into a storage space and a drainage space below the storage space, for filtering rainwater. The first drainage section provided in the drainage space, A second drainage section is provided below the aforementioned side ditch and above the aforementioned storage space, Equipped with, The second drainage section is, One end of the first main pipe is connected to the aforementioned side ditch and extends downward, One end of the first main pipe is connected to the other end of the second main pipe, and the second main pipe extends substantially horizontally above the storage tank, A branch pipe is connected at one end to the second main pipe and at the other end to the storage tank, Equipped with, The aforementioned second main pipe is a storage and drainage structure whose other end is guided toward the main sewer line.

3. The storage and drainage structure according to claim 1 or 2, wherein the storage tank has a storage capacity such that, when the rainwater precipitation is 50 mm per hour, the height of the water level of rainwater formed in the storage space of the storage tank after one hour is vertically lower than the height of the second drainage section.

4. The storage and drainage structure according to claim 1 or claim 2, wherein the pore diameter of the filter is less than 5 mm.

5. The storage and drainage structure according to claim 1 or claim 2, wherein the filter is made of stainless steel.

6. The storage and drainage structure according to claim 1 or claim 2, further comprising a separation unit for centrifuging rainwater drained from the first drainage unit or the second drainage unit.

7. The storage and drainage structure according to claim 2, wherein the side ditch is provided with a filtration device for filtering rainwater.

8. The aforementioned side ditch extends along the inflow and outflow direction of rainwater flow, and has a bottom portion and side portions that protrude upward from both sides of the bottom portion in the width direction. The aforementioned filtration device is A cylindrical part having an opening on the inflow side in the aforementioned inflow / outflow direction, a bottomed cylindrical shape with a central axis in the aforementioned inflow / outflow direction, and whose shape can be arbitrarily changed to match the shape of the inner surface of the bottom and side of the side ditch, An inlet-side inner mesh portion having a tapered surface that extends from the periphery of the opening of the cylindrical portion toward the outflow side in the inflow / outflow direction so as to approach the central axis and is formed in the circumferential direction of the central axis, and a mesh portion opening provided at the outflow-side end of the tapered surface, The storage and drainage structure according to claim 7, comprising:

9. The aforementioned side ditch extends along the inflow and outflow direction of rainwater flow, and has a bottom portion and side portions that protrude upward from both sides of the bottom portion in the width direction. The aforementioned filtration device is The outer wall portion is formed in the shape of the inner surface of the bottom and side of the side ditch, and forms a flow channel space inside, A first wall portion is formed in the channel space and restricts the flow of rainwater within a predetermined range from the lowest point of the channel space upwards, A second wall portion is formed in the flow path space and, on the outflow side in the inflow / outflow direction from the first wall portion, restricts the flow of water in a predetermined range from the top of the flow path space downwards, The storage and drainage structure according to claim 7, comprising:

10. The storage and drainage structure according to claim 9, wherein the first wall portion and the second wall portion are provided alternately in multiple locations.

11. The storage and drainage structure according to claim 9, wherein a filter for filtering rainwater is provided at the outflow end of the outer wall portion in the inflow / outflow direction.

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