Rainwater treatment system

Abstract

The rainwater treatment system 1 includes an initial rainwater separation tank 10, a first filtration tank 20, a rainwater channel 30, an adjustment storage tank 40, a second filtration tank 50, and a water storage tank 60. The initial rainwater separation tank 10 communicates with an upper rain gutter 7 and a lower rain gutter 8 for draining rainwater accumulated on the roof of a building to a roadside ditch or a river. The first filtration tank 20 filters the rainwater supplied from the initial rainwater separation tank 10 to generate filtered water. The rainwater channel 30 introduces rainwater from the initial rainwater separation tank 10 to the first filtration tank 20. The adjustment storage tank 40 stores the filtered water supplied from the first filtration tank 20. The second filtration tank 50 further filters the filtered water supplied from the first filtration tank 20 and the adjustment storage tank 40 to generate pure water. The water storage tank 60 stores the pure water obtained by further filtering the filtered water.

Description

Technical Field

[0001] The present invention relates to a rainwater treatment system. More specifically, it relates to a rainwater treatment system for treating rainwater for use, for example.

Background Art

[0002] Rainwater is used for various purposes, such as watering plants, flushing toilets, washing cars, and as domestic water in emergencies such as disasters. In order to achieve such "rainwater utilization", rainwater is collected, stored, and further purified.

[0003] In recent years, "rainwater utilization" has been emphasized from the perspective of disaster prevention. For example, during heavy rain, rainwater is stored in a storage tank, and the stored rainwater is gently discharged on sunny days to maintain the drainage function in urban areas and prevent floods on roads.

[0004] Conventionally, various technologies for realizing rainwater utilization have been proposed. For example, Patent Document 1 describes a rainwater storage device that can suitably cope not only with initial rainwater but also with heavy rain without being accompanied by enlargement or complexity.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the control unit provided in the rainwater storage device described in Patent Document 1 requires an external power source, and there is a problem that the device does not operate when a power failure occurs due to a disaster such as an earthquake.

[0007] In addition, the rainwater storage device described in Patent Document 1 allows a part of the collected rainwater to overflow through an overflow pipe and be discharged to a sewer, but rainwater is a precious resource that can be used for various purposes, and it has been desired to process and utilize rainwater efficiently while minimizing waste as much as possible.

[0008] The present invention was devised in view of the above points, and an object thereof is to provide a rainwater treatment system that does not require external power and can efficiently treat rainwater.

Means for Solving the Problems

[0009] In order to achieve the above object, the rainwater treatment system of the present invention includes a first filtration tank having a first filter capable of filtering introduced rainwater to generate filtered water, a conditioning storage tank communicating with the first filtration tank and capable of storing the filtered water generated by the first filtration tank, and a water storage tank communicating with the first filtration tank and the conditioning storage tank, capable of storing the filtered water, and having a maximum water level at which the filtered water can be stored lower than the maximum water level that can be stored in the conditioning storage tank.

[0010] Here, the first filtration tank having the first filter capable of filtering the introduced rainwater to generate filtered water can capture impurities contained in the rainwater introduced into the first filtration tank.

[0011] In addition, the conditioning storage tank communicating with the first filtration tank and capable of storing the filtered water generated by the first filtration tank increases the storage capacity of the filtered water and enables efficient treatment of rainwater.

[0012] That is, it is necessary to ensure the head pressure with respect to "the water level of the rainwater introduced into the first filtration tank", and since "the maximum water level of the filtered water that can be stored in the water storage tank" is limited (in other words, since the height of the water storage tank is limited), when the conditioning storage tank is not provided, when the water storage tank is full, the first filtration tank has no choice but to drain the rainwater without filtering it.

[0013] On the other hand, when an adjustment storage tank is provided, even when the water storage tank is full, filtered water can be stored until the adjustment storage tank is full, and it is difficult for a situation to occur where the first filtration tank has to drain rainwater without filtering it (for example, even in the case of heavy rainstorms, the drainage of rainwater is reduced), and as described above, rainwater can be efficiently treated.

[0014] Although it is possible to increase the water storage capacity of filtered water by increasing the capacity of the water storage tank or the number of water storage tanks, considering that the height of the water storage tank is restricted to ensure the water head pressure, the installation area of the rainwater treatment system will become large.

[0015] On the other hand, for the "maximum water level of filtered water that can be stored in the adjustment storage tank", there is no need to ensure the water head pressure between it and the "water level of rainwater introduced into the first filtration tank", and there are no particular restrictions (in other words, since the height of the adjustment storage tank is not restricted), the water storage capacity of filtered water can be increased in the height direction (vertical direction), and the installation area of the rainwater treatment system will not become excessively large.

[0016] Furthermore, when the "maximum water level that can be stored in the water storage tank" is located below the "maximum water level that can be stored in the adjustment storage tank" (below in the vertical direction), when the water level of the filtered water stored in the water storage tank drops, it is possible to supply the filtered water stored in the adjustment storage tank to the water storage tank without the need for external power.

[0017] In addition, when an initial rainwater separation tank having a first water channel communicating with a predetermined rain gutter, a second water channel communicating with the first water channel at a first height position and into which rainwater exceeding the first height position is introduced, and a third water channel communicating with the second water channel at a second height position and communicating with the first filtration tank at a third height position above the second height position and introducing rainwater exceeding the third height position into the first filtration tank is provided, impurities contained in the rainwater can be reduced at a stage prior to being introduced into the first filtration tank.

[0018] That is, rainwater can be stored in the "area below the first height of the first water channel", the "area below the second height of the second water channel", and the "area below the third height of the third water channel" in the initial rainwater separation tank. Since dust, dirt, sand, etc. in the atmosphere can be precipitated and separated in these areas, as described above, the impurities contained in the rainwater can be reduced.

[0019] Furthermore, when the communication height position between the first filtration tank and the water storage tank in the adjustment storage tank is below the maximum water level that can be stored in the water storage tank, until the "water level of the filtered water stored in the water storage tank" reaches the "communication height position (vertical position) between the first filtration tank and the water storage tank in the adjustment storage tank", no external power is required, and the filtered water stored in the adjustment storage tank can be supplied to the water storage tank.

[0020] In addition, when a second filtration tank having a second filter for further filtering the introduced filtered water is provided, impurities contained in the rainwater can be captured more sufficiently by two-stage filtration of the first filter and the second filter.

[0021] For example, in the case where impurities that could not be captured by the first filter due to deterioration of the first filter or the like are captured by the second filter. Also, by using different materials for the first filter and the second filter, various impurities contained in the rainwater can be efficiently captured.

[0022] Furthermore, when the water storage tank communicates with the first filtration tank and the adjustment storage tank via the second filtration tank, the filtered water that has undergone two-stage filtration of the first filter and the second filter can be stored in the water storage tank.

[0023] In addition, when the communication height position between the first filtration tank and the second filtration tank in the adjustment storage tank is below the maximum water level that can be introduced into the second filtration tank, until the "water level of the filtered water introduced into the second filtration tank" reaches the "communication height position (vertical position) between the first filtration tank and the second filtration tank in the adjustment storage tank", no external power is required, and the filtered water stored in the adjustment storage tank can be supplied to the second filtration tank.

[0024] Also, when the maximum water level that can be stored in the adjustment storage tank is the same as the maximum water level that can be introduced into the first filtration tank, the filtered water can be stored in the adjustment storage tank most efficiently.

[0025] That is, since the "water level of the filtered water stored in the adjustment storage tank" is the same height (vertical height) as the "water level of the rainwater introduced into the first filtration tank", by configuring the adjustment storage tank so that the "maximum water level that can be stored in the adjustment storage tank" is the same as the "maximum water level that can be introduced into the first filtration tank", the storage capacity of the filtered water in the height direction (vertical direction) can be increased to the maximum, and the total capacity of the adjustment storage tank can be utilized without waste.

[0026] Also, when provided with a valve that restricts the introduction of filtered water from the first filtration tank to the adjustment storage tank, for example, in a period of little rain, it is possible to respond to a mode such as storing water only in the water storage tank without storing the filtered water in the adjustment storage tank.

Advantages of the Invention

[0027] The rainwater treatment system according to the present invention does not require external power and can efficiently treat rainwater.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0029] Hereinafter, embodiments for carrying out the invention (hereinafter referred to as "embodiments") will be described with reference to the drawings for the purpose of providing an understanding of the present invention.

[0030] The rainwater treatment system 1 of the present invention shown in FIGS. 1 and 2 includes an initial rainwater separation tank 10 communicating with an upper rain gutter 7 and a lower rain gutter 8 for draining rainwater accumulated on the roof of a building, for example, into a roadside ditch or a river.

[0031] The rainwater treatment system 1 of the present invention also includes a first filtration tank 20 that filters rainwater supplied from the initial rainwater separation tank 10 to generate filtered water. Furthermore, the rainwater treatment system 1 of the present invention includes a rainwater channel 30 for introducing rainwater into the first filtration tank 20.

[0032] The rainwater treatment system 1 of the present invention also includes an adjustment storage tank 40 that stores the filtered water supplied from the first filtration tank 20. Furthermore, the rainwater treatment system 1 of the present invention includes a second filtration tank 50 that further filters the filtered water supplied from the first filtration tank 20 and the adjustment storage tank 40 to generate pure water.

[0033] The rainwater treatment system 1 of the present invention also includes a water storage tank 60 that stores pure water (here, "pure water" is a kind of "filtered water" because it is obtained by further filtering the filtered water).

[0034] The initial rainwater separation tank 10, the first filtration tank 20, the adjustment storage tank 40, the second filtration tank 50, and the water storage tank 60 are arranged on the same ground surface 6. Note that the first filtration tank 20 is installed on a foundation pedestal 24 installed on the ground surface 6, and the adjustment storage tank 40 is also installed on a foundation pedestal 43 installed on the ground surface 6.

[0035] Hereinafter, the detailed structures of each component will be described. Specifically, the "initial rainwater separation tank", "first filtration tank", "rainwater channel", "adjustment storage tank", "second filtration tank", "water storage tank", "filtered water channel", and "overflow water channel" will be described.

[0036] (Initial rainwater separation tank) The initial rainwater separation tank 10 has a first vertical water channel 11. The first vertical water channel 11 extends in the vertical direction. The upper end of the first vertical water channel 11 is connected in a communicating state to the upper rain gutter 7, and the lower end of the first vertical water channel 11 is connected in a communicating state to the lower rain gutter 8.

[0037] Also, the upper rain gutter 7 is connected in a communicating state to the roof of a building or the like, and the lower rain gutter 8 is connected in a communicating state to a roadside ditch of a road or the like. Further, a first vertical water channel valve 14 for controlling the drainage volume is attached to the lower part of the first vertical water channel 11.

[0038] Thereby, the rainwater accumulated on the roof of a building or the like flows into the upper rain gutter 7. When the first vertical water channel valve 14 is closed, the rainwater accumulates in the first vertical water channel 11. On the other hand, when the first vertical water channel valve 14 is open, the rainwater is drained from the lower rain gutter 8 to a roadside ditch of a road or the like.

[0039] Also, the initial rainwater separation tank 10 has a second vertical water channel 12. The second vertical water channel 12 is arranged at a position closer to the first filtration tank 20 than the first vertical water channel 11 and extends in the vertical direction. Furthermore, the upper part in the vertical direction of the second vertical water channel 12 is connected in a communicating state to the upper part in the vertical direction of the first vertical water channel 11.

[0040] In addition, the initial rainwater separation tank 10 has a third vertical water channel 13. The third vertical water channel 13 is arranged at a position closer to the first filtration tank 20 than the second vertical water channel 12 and extends in the vertical direction. Also, the lower part in the vertical direction of the third vertical water channel 13 communicates with the lower part in the vertical direction of the second vertical water channel 12, and the upper part in the vertical direction of the third vertical water channel 13 is connected in a state of communicating with the rainwater channel 30.

[0041] As shown in FIG. 3 in which a part of the outer wall of the third vertical water channel 13 is omitted, an impurity removal screen 15 is attached inside the third vertical water channel 13. When rainwater passes through the impurity removal screen 15, large impurities such as leaves contained in the rainwater are removed from the rainwater.

[0042] Furthermore, a backflow prevention valve 16 for preventing "backflow" of rainwater flowing from the rainwater channel 30 to the third vertical water channel 13 is provided at the connection part (horizontal part) between the third vertical water channel 13 and the rainwater channel 30. The arrows in FIG. 3 indicate the direction of the flow of rainwater.

[0043] Also, openings for communicating the inside and the outside are formed at the upper and lower ends of the third vertical water channel 13, and maintenance covers 17 that can close the respective openings in an openable and closable manner are attached.

[0044] Here, in a configuration where the backflow prevention valve 16 is not provided, when the maintenance cover 17 at the lower end of the third vertical water channel 13 is opened, the rainwater in the first filtration tank 20 will flow back and be drained (the rainwater in the first filtration tank 20 will flow back and be drained until the water level of the rainwater in the first filtration tank 20 falls below the position of the rainwater channel 30). Therefore, the rainwater treatment system 1 of the present invention adopts a configuration in which, by providing the backflow prevention valve 16, the rainwater in the first filtration tank 20 does not flow back during maintenance and no extra drainage is performed.

[0045] Although it is possible to perform maintenance on the impurity removal screen 15 using only the opening at the lower end of the third vertical water channel 13, in the rainwater treatment system 1 of the present invention, an opening is also provided at the upper end of the third vertical water channel 13 so that maintenance can be easily performed.

[0046] (First filtration tank) The first filtration tank 20 has an inner wall made of a resin material and an outer wall made of a heat insulating material, and extends in the vertical direction. Further, the first filtration tank 20 has a cavity formed inside and is formed in a substantially cylindrical shape.

[0047] An opening communicating the inside and the outside is formed at the upper end of the first filtration tank 20, and the lower end of the first filtration tank 20 is closed. Furthermore, an inspection lid 25 that can open and close the upper end opening is provided at the upper end of the first filtration tank 20.

[0048] The first filtration tank 20 also has a first filter 21. The first filter 21 can filter rainwater to generate filtered water, and a cavity for the filtered water to pass through is formed inside along the length direction.

[0049] Openings communicating the internal cavity and the outside are formed at the upper and lower ends of the first filter 21, and it is formed in a vertically long substantially cylindrical shape as a whole. Furthermore, as shown in FIG. 4, the first filter 21 is disposed inside the first filtration tank 20 in a state of extending in the vertical direction.

[0050] The first filter 21 also has a filter cloth made of a non-woven fabric or a woven fabric, and is configured, for example, in a two-layer structure including an inner layer and an outer layer. Furthermore, "the size of the mesh of the inner layer filter cloth" and "the size of the mesh of the outer layer filter cloth" are different from each other. As a result, fine gaps are formed on the surface of the first filter 21, which can capture impurities of various sizes and suppress clogging.

[0051] Here, the first filter 21 does not necessarily have to be configured with a two-layer structure and may not have fine gaps formed therein, and may be configured with a known filter medium. However, as in the present embodiment, by forming a large number of fine gaps on the surface of the first filter 21, it is possible to secure a filtration area, disperse the differential pressure of the head pressure, and prevent clogging due to the captured impurities, which is preferable.

[0052] Further, the first filtration tank 20 has an internal pipe 22 having a substantially T-shaped configuration. Here, the connecting end portion 22A of the internal pipe 22 is connected to communicate with the lower end of the first filter 21.

[0053] That is, an opening for communicating the inside and the outside of the internal pipe 22 is formed in the connecting end portion 22A, and a part of the internal pipe 22 extends in the direction in which the first filter 21 extends. Further, the connecting end portion 22A of the internal pipe 22 is detachably connected to the lower end of the first filter 21 by the first filter insertion portion 26.

[0054] Further, the end portion of the internal pipe 22 on the side opposite to the connecting end portion 22A is attached to the bottom of the first filtration tank 20.

[0055] Furthermore, the end portion of the branched and extending portion of the internal pipe 22 is an "external communication end portion 22B", and the external communication end portion 22B protrudes outside the first filtration tank 20 and communicates with the outside of the first filtration tank 20. That is, an opening for communicating the inside and the outside of the internal pipe 22 is formed in the external communication end portion 22B.

[0056] In addition, the external communication end portion 22B of the internal pipe 22 included in the first filtration tank 20 is a location where the first filtration tank 20 communicates with the adjustment storage tank 40.

[0057] Further, the upper end of the first filter 21 is detachably connected to an inspection lid 25 provided at the upper end of the first filtration tank 20. Thus, during maintenance, the operator can open the inspection cover 25 to check the internal condition and replace the first filter 21.

[0058] Also, with the inspection cover 25 open, by supplying filtered water from the opening at the upper end of the first filter 21, the impurities adhering to the first filter 21 can be washed off by backwashing.

[0059] In addition, a drain faucet 23 is provided on the side near the bottom of the first filtration tank 20 so that the impurities accumulated at the bottom of the first filtration tank 20 can be discharged together with rainwater.

[0060] (Rainwater channel) The rainwater treatment system 1 of the present invention includes a rainwater channel 30, and one end of the rainwater channel 30 is blocked. An ejection hole 31 that communicates the inside and outside of the rainwater channel 30 is formed on the side near the blocked end of the rainwater channel 30.

[0061] Also, the rainwater channel 30 protrudes into the cavity inside the first filtration tank 20 and is connected to the side of the first filtration tank 20 in a communicating state.

[0062] Also, as shown in FIG. 5, one end of the rainwater channel 30 is blocked in the radial direction of the first filtration tank 20, and the ejection hole 31 opens in a direction substantially orthogonal to the radial direction of the first filtration tank 20.

[0063] Also, as shown in FIG. 4, the rainwater channel 30 is located vertically below the connection point between the internal pipe 22 and the first filter 21 (i.e., the first filter insertion part 26). Furthermore, the connection point between the internal pipe 22 and the first filter 21 is located vertically below the approximate center of the first filtration tank 20. As a result, the rainwater channel 30 is located vertically below the approximate center of the first filtration tank 20.

[0064] As a result, in the first filtration tank 20, rainwater accumulates at least from the bottom of the first filtration tank 20 to the connection point between the internal pipe 22 and the first filter 21 (i.e., the position of the first filter insertion part 26). Consequently, the rainwater channel 30 will be located below the water surface of the rainwater.

[0065] Then, rainwater jets from the jet holes 31 of the rainwater channel 30 located below the water surface toward the curved inner wall of the first filtration tank 20, generating a swirling water flow. By the centrifugal separation effect of the swirling water flow, impurities in the rainwater can be separated.

[0066] Also, since the upper part in the vertical direction of the third vertical water channel 13 is connected to the rainwater channel 30 in a communicating state and is located vertically below the approximate center part of the first filtration tank 20, the third vertical water channel 13 is also located vertically below the approximate center part of the first filtration tank 20.

[0067] As a result, the third vertical water channel 13 is at a relatively low position, and the cleaning work of the impurity removal screen 15 inside the third vertical water channel 13 does not require working at heights, thus improving the safety and workability of maintenance.

[0068] Also, rainwater is introduced from the rainwater channel 30 into the first filtration tank 20. When the water level of the rainwater in the first filtration tank 20 exceeds the connection point between the internal pipe 22 and the first filter 21 (i.e., the position of the first filter insertion part 26), the rainwater is filtered through the first filter 21, becomes filtered water, and flows into the inside of the internal pipe 22, and then flows out from the external communication end part 22B to the outside of the first filtration tank 20 by gravity. Note that the arrows in FIGS. 4 and 5 indicate the flow directions of the rainwater and the filtered water.

[0069] Also, since the rainwater channel 30 is located "below the water surface of the rainwater", there is no "drop between the lowest water level (the position of the connection point between the internal pipe 22 and the first filter 21) and the rainwater introduction position" that occurs when the rainwater channel 30 is located above the water surface. As a result, the impurities accumulated at the bottom of the first filtration tank 20 are not lifted up, and it is difficult for the first filter 21 to be clogged by the lifted-up impurities.

[0070] Furthermore, since the stormwater drain 30 is located "vertically below the connection point between the internal pipe 22 and the first filter 21", it is easier to safely perform regular maintenance on the stormwater drain 30 than when it is located vertically above (for example, near the upper end of the first filtration tank 20).

[0071] (Adjustment storage tank) The adjustment storage tank 40 communicates with the first filtration tank 20. The upper end position of the adjustment storage tank 40 in the vertical direction (where the "upper end position" here means the highest water level of the filtered water that can be stored in the adjustment storage tank 40) is substantially the same as the upper end position of the first filtration tank 20 (where the "upper end position" here means the highest water level of the rainwater that can be introduced into the first filtration tank 20).

[0072] Also, the volume of the adjustment storage tank 40 is larger than the volume of the first filtration tank 20. Furthermore, a filtered water inlet / outlet 41 is provided in the adjustment storage tank 40, and the filtered water is introduced into or discharged from the adjustment storage tank 40 through the filtered water inlet / outlet 41.

[0073] Also, the filtered water inlet / outlet 41 of the adjustment storage tank 40 is the location where it "communicates with the first filtration tank 20 and the second filtration tank 50" in the adjustment storage tank 40. Note that the filtered water inlet / outlet 41 is provided vertically below the upper end position line (the position indicated by reference numeral 58 in FIG. 1, which is the same as the "upper end position of the water storage tank 60") indicating the "upper end position of the second filtration tank 50" to be described later.

[0074] Also, a drain faucet 42 is provided on the side surface near the bottom of the adjustment storage tank 40 so as to be able to discharge the filtered water remaining at the bottom.

[0075] (Second filtration tank) As shown in FIG. 6, the second filtration tank 50 extends in the vertical direction, and the cross-sectional shape of the second filtration tank 50 in a direction substantially orthogonal to the extending direction is substantially circular. In addition, an opening is formed at the upper end of the second filtration tank 50 for introducing filtered water into the interior or discharging pure water from the interior, and the lower end of the second filtration tank 50 is closed.

[0076] Moreover, the upper end position of the second filtration tank 50 (here, the "upper end position" means the highest water level of the filtered water that can be introduced into the second filtration tank 50) is located vertically below the upper end position of the first filtration tank 20 and the upper end position of the adjustment storage tank 40.

[0077] In addition, the second filtration tank 50 has a second filter 51. The second filter 51 can further filter the filtered water to generate pure water, and is formed in a substantially cylindrical shape with a cavity 53 provided inside.

[0078] Moreover, the second filter 51 is disposed inside the second filtration tank 50 in a state of extending in the direction in which the second filtration tank 50 extends. Furthermore, a gap 52 is formed between the inner wall of the second filtration tank 50 and the second filter 51.

[0079] In addition, the second filter 51 is filled with an ion exchange resin, and can adsorb "salt components such as calcium, sodium, and chloride" and metal ions contained in the filtered water sent from the first filtration tank 20 and the adjustment storage tank 40. Thereby, the second filter 51 can remove impurities that cannot be removed by the first filter 21 and generate high-purity pure water.

[0080] In addition, at the upper end of the second filtration tank 50, a filtered water inlet 54 is formed that opens in a direction substantially orthogonal to the direction in which the second filtration tank 50 extends. Furthermore, the filtered water inlet 54 communicates with the gap 52.

[0081] On the side opposite to the filtered water inlet 54 at the upper end of the second filtration tank 50, a pure water outlet 55 is formed that opens in a direction substantially orthogonal to the direction in which the second filtration tank 50 extends. Furthermore, the pure water outlet 55 communicates with the cavity 53 inside the second filter 51. On the other hand, the filtered water inlet 54 and the pure water outlet 55 do not communicate directly with each other.

[0082] Also, at the upper end of the second filtration tank 50, a drain plug 56 on the filtered water inlet side and a drain plug 57 on the pure water outlet side, which are plugs for venting air, are attached.

[0083] As a result, the filtered water introduced into the second filtration tank 50 from the filtered water inlet 54 flows into the gap 52, then passes through the second filter 51 and is filtered, becoming pure water and flowing into the cavity 53 inside the second filter 51.

[0084] Here, since the pure water does not flow from the cavity 53 inside the second filter 51 through the second filter 51 again and into the gap 52, it accumulates in the cavity 53 of the second filter 51, and the water level of the pure water in the cavity 53 rises.

[0085] And when the water level of the pure water in the cavity 53 reaches the upper end of the second filtration tank 50, the pure water flows out of the second filtration tank 50 from the pure water outlet 55. Note that the arrows in Fig. 6(a) indicate the flow directions of the filtered water and the pure water.

[0086] (Water storage tank) The water storage tank 60 communicates with the first filtration tank 20 and the adjustment storage tank 40 via the second filtration tank 50. Also, the upper end position of the water storage tank 60 (here, the "upper end position" means the highest water level of the pure water that can be stored in the water storage tank 60) is located vertically below the upper end positions of the first filtration tank 20 and the adjustment storage tank 40.

[0087] Moreover, the upper end position of the water storage tank 60 in the vertical direction is approximately the same as the upper end position of the second filtration tank 50.

[0088] Furthermore, the upper end of the water storage tank 60 and the upper end of the second filtration tank 50 communicate with each other. Here, the water storage tank 60 communicates with two second filtration tanks 50 arranged in parallel with respect to the water storage tank 60.

[0089] Also, a water intake passage 61 formed in a substantially T shape is connected to the side surface near the bottom of the water storage tank 60 in a state of communicating with the inside of the water storage tank 60. Furthermore, a water intake faucet 62 is provided at the end of the water intake passage 61, and the pure water in the water storage tank 60 can be taken out from the water storage tank 60 by the water intake faucet 62.

[0090] (Filtration water passage) Also, the first filtration tank 20, the adjustment storage tank 40, the second filtration tank 50, and the water storage tank 60 communicate with each other via a filtration water passage 2 through which the filtered water can flow.

[0091] The filtration water passage 2 has a "first horizontal part 2A", a "first branch part 2B", a "second horizontal part 2C", a "vertical part 2D", a "third horizontal part 2E", a "fourth horizontal part 2F", a "drain vertical part 2G", a "second branch part 2H", a "fifth horizontal part 2I", a "sixth horizontal part 2J", and a "drain faucet 2K".

[0092] One end of the first horizontal part 2A is connected in a state of communicating with the external communication end 22B of the internal pipe 22 of the first filtration tank 20. Also, the other end of the first horizontal part 2A is connected in a state of communicating with the first branch part 2B.

[0093] Also, the first branch part 2B branches in three directions and is connected to the "first horizontal part 2A" communicating with the first filtration tank 20, the "second horizontal part 2C" directed to the adjustment storage tank 40, and the "fourth horizontal part 2F" directed to the second filtration tank 50.

[0094] Also, one end of the second horizontal part 2C is connected in a state of communicating with the first branch part 2B. Furthermore, the other end of the second horizontal part 2C is connected in a state of communicating with the lower end of the vertical part 2D.

[0095] Moreover, the upper end of the vertical portion 2D is connected in a state of communicating with one end of the third horizontal portion 2E. Further, the other end of the third horizontal portion 2E is connected in a state of communicating with the filtered water inlet / outlet 41 of the adjustment storage tank 40.

[0096] Note that an adjustment storage tank valve 3 is attached to the second horizontal portion 2C, and the amount of filtered water introduced into the adjustment storage tank 40 or the amount of filtered water discharged from the adjustment storage tank 40 to the second filtration tank 50 can be controlled by the adjustment storage tank valve 3.

[0097] One end of the fourth horizontal portion 2F is connected in a state of communicating with the first branch portion 2B. Further, the other end of the fourth horizontal portion 2F is connected in a state of communicating with the substantially central portion (central portion in the vertical direction) of the drainage vertical portion 2G.

[0098] Note that a second filtration tank valve 4 is attached to the fourth horizontal portion 2F, and the amount of filtered water introduced into the second filtration tank 50 can be controlled by the second filtration tank valve 4.

[0099] Moreover, the upper end of the drainage vertical portion 2G is connected in a state of communicating with the second branch portion 2H. The second branch portion 2H branches in three directions and is connected to the "drainage vertical portion 2G" communicating with the first filtration tank 20 and the adjustment storage tank 40, and a pair of "fifth horizontal portions 2I" directed toward each of the pair of second filtration tanks 50.

[0100] One end of the pair of "fifth horizontal portions 2I" is connected in a state of communicating with the second branch portion 2H. Further, the other end of the pair of "fifth horizontal portions 2I" is connected in a state of communicating with the filtered water inlets 54 of each of the pair of "second filtration tanks 50".

[0101] One end of the pair of "sixth horizontal portions 2J" is connected in a state of communicating with the pure water outlets 55 of each of the pair of "second filtration tanks 50". Further, the other end of the pair of "sixth horizontal portions 2J" is connected in a state of communicating with a pair of pure water inlets 63 formed at the upper end of the water storage tank 60.

[0102] In addition, valves 5 for the water storage tank are respectively attached to a pair of "sixth horizontal parts 2J", and the amount of pure water introduced into the water storage tank 60 can be controlled by the valves 5 for the water storage tank.

[0103] Further, a drain faucet 2K, which is an openable and closable opening, is provided at the lower end of the drain vertical part 2G. Through such a drain faucet 2K, the filtered water can be drained.

[0104] By the way, as a countermeasure against the problem that fine air bubbles stay in the upper inner part (upper part inside) of the "horizontal part" such as the first horizontal part 2A of the filtration water channel 2 and the flow of the filtered water deteriorates, a drain vertical part 2G of the filtration water channel 2 is provided. That is, by providing the drain vertical part 2G, the air bubbles are not retained in the horizontal part in the filtration water channel 2, but are guided through the fifth horizontal part 2I to the drain plug 56 on the filtered water inlet side of the second filtration tank 50, and the air is removed from the drain plug 56 on the filtered water inlet side, thereby suppressing the deterioration of the flow of the filtered water.

[0105] (Overflow water channel) The overflow water channel 70 is connected to the side surface near the upper end of the first filtration tank 20 in a state of communicating with the cavity inside the first filtration tank 20. The overflow water channel 70 is a water channel for draining rainwater to the outside of the first filtration tank 20 when the water level of the rainwater in the first filtration tank 20 reaches a level close to full water.

[0106] The rainwater treatment system 1 of the present invention includes a circulation path 71 extending in the horizontal direction below the filtration water channel 2 in the vertical direction. In addition, the lower part of the first vertical water channel 11, the lower part of the second vertical water channel 12, and the lower part of the overflow water channel 70 communicate with the circulation path 71.

[0107] Thereby, the rainwater flows into the circulation path 71 through the first vertical water channel 11, the second vertical water channel 12, and the overflow water channel 70, and is discharged to the lower rain gutter 8 communicating with the lower part of the first vertical water channel 11 through the circulation path 71.

[0108] Also, a first circulation path valve 71A is attached to a water path that connects the lower part of the second vertical water path 12 and the circulation path 71. The first circulation path valve 71A can control the drainage volume of rainwater accumulated in the second vertical water path 12, the third vertical water path 13, and the first filtration tank 20.

[0109] Also, the circulation path 71 is connected in a state of being in communication with the water intake path 61 of the water storage tank 60. Specifically, it is connected in a state of being in communication with the "end of the water intake path 61" on the side opposite to the end where the water intake faucet 62 is provided.

[0110] Also, a second circulation path valve 71B is attached to the circulation path 71. The second circulation path valve 71B can prevent unfiltered rainwater from mixing with the pure water in the water intake path 61 of the water storage tank 60 as it passes through the circulation path 71.

[0111] (Modification Example 1) The rainwater treatment system 1 of the present invention may be configured not to include the initial rainwater separation tank 10. However, by providing the initial rainwater separation tank 10, dust, dirt, sand, etc. in the atmosphere contained in the initial rainwater can be sufficiently separated, and then the rainwater can be introduced into the first filtration tank 20.

[0112] (Modification Example 2) Also, the rainwater treatment system 1 of the present invention may be configured not to include the second filtration tank 50. However, by providing the second filtration tank 50, the filtered water obtained by filtration in the first filtration tank 20 can be further filtered to generate pure water.

[0113] (Modification Example 3) Also, in the example shown in FIG. 1, an example of a configuration in which filtered water can be directly supplied from the first filtration tank 20 to the second filtration tank 50 is given, but it is of course not limited to this configuration. For example, the first filtration tank 20 and the adjustment storage tank 40 can be arranged in series so that the filtered water derived from the first filtration tank 20 is always supplied to the second filtration tank 50 through the adjustment storage tank 40.

[0114] Next, the flow of rainwater treatment using the rainwater treatment system 1 of the present invention will be described.

[0115] When it rains, the rainwater accumulated on the roof of the building or the like flows into the upper rain gutter 7, and the rainwater flows from the upper rain gutter 7 into the first vertical water passage 11 of the initial rainwater separation tank 10.

[0116] Next, when the first vertical water passage 11 is filled with rainwater, the rainwater overflowing from the first vertical water passage 11 flows into the second vertical water passage 12. Also, as the inflow of rainwater into the second vertical water passage 12 progresses and the water level in the second vertical water passage 12 rises to the position of the communication point with the third vertical water passage 13, rainwater also flows into the third vertical water passage 13.

[0117] After rainwater flows into the third vertical water passage 13, the water levels in the second vertical water passage 12 and the third vertical water passage 13 rise at the same water level. And when the water levels in the second vertical water passage 12 and the third vertical water passage 13 rise to the position of the rainwater passage 30, the rainwater flows into the first filtration tank 20 through the rainwater passage 30.

[0118] When the water level of the rainwater in the first filtration tank 20 exceeds the position of the connection point between the internal pipe 22 and the first filter 21 (that is, the first filter insertion part 26), the rainwater is filtered through the first filter 21 and becomes filtered water. The filtered water flows into the inside of the internal pipe 22 through the cavity inside the first filter 21 and flows out of the first filtration tank 20 from the external communication end part 22B by gravity.

[0119] Note that when rainwater flows into the first filtration tank 20 and the water level rises and the water head pressure increases, the amount passing through the first filter 21 (that is, the water passing amount) also increases accordingly.

[0120] When the water level in the first filtration tank 20 reaches the position of the overflow water channel 70, the water head pressure becomes maximum, and rainwater is filtered across the entire surface of the first filter 21. As a result, the filtration area increases and the resistance of the first filter 21 decreases, further increasing the water flow rate and maximizing the treatment capacity.

[0121] Also, when the water level of the rainwater in the first filtration tank 20 exceeds the position of the connection point between the internal pipe 22 and the first filter 21 (i.e., the first filter insertion part 26), the rainwater channel 30 is positioned below the water surface of the rainwater. Rainwater is ejected from the ejection holes 31 of the rainwater channel 30 positioned below the water surface toward the curved inner wall of the first filtration tank 20, generating a swirling water flow. Due to the centrifugal separation action of the swirling water flow, among the impurities contained in the rainwater, those with a specific gravity heavier than that of the rainwater flow along the inner wall of the first filtration tank 20 and accumulate at the bottom of the first filtration tank 20.

[0122] On the other hand, impurities with the same specific gravity as or lighter than that of the rainwater are induced toward the center side of the first filtration tank 20 together with the rainwater.

[0123] The rainwater induced toward the center side of the first filtration tank 20 comes into contact with the first filter 21. When the rainwater passes through the filter cloth of the first filter 21, the impurities contained in the rainwater are captured, and the filtered water that has passed through the filter cloth flows into the interior of the internal pipe 22 through the cavity inside the first filter 21 and flows out from the external communication end portion 22B to the outside of the first filtration tank 20.

[0124] Here, the filtered water flowing out from the external communication end portion 22B of the first filtration tank 20 fills the filtration water channel 2. When the water level of the filtered water reaches the filtered water introduction and outlet 41, the filtered water flows into the adjustment storage tank 40. Specifically, the filtered water flows into the adjustment storage tank 40 through the first horizontal portion 2A, the first branch portion 2B, the second horizontal portion 2C, the vertical portion 2D, and the third horizontal portion 2E of the filtration water channel 2.

[0125] Then, as the water level of the filtered water flowing into the adjustment storage tank 40 rises and reaches the "upper end position line (which is the upper end position of the second filtration tank 50 and the upper end position of the water storage tank 60)" indicated by reference numeral 58, the filtered water flows into the second filtration tank 50. Specifically, the filtered water flows into the second filtration tank 50 through the first horizontal portion 2A, the first branch portion 2B, the fourth horizontal portion 2F, the drain vertical portion 2G, the second branch portion 2H, and the fifth horizontal portion 2I of the filtration water channel 2.

[0126] The filtered water introduced into the second filtration tank 50 from the filtered water inlet 54 of the second filtration tank 50 flows into the gap 52 in the second filtration tank 50, passes through the second filter 51, is further filtered, becomes pure water, and flows into the cavity 53 inside the second filter 51.

[0127] As the pure water flowing into the cavity 53 accumulates and the water level of the pure water rises and reaches the upper end of the second filtration tank 50, the pure water flows out of the second filtration tank 50 from the pure water outlet 55.

[0128] The pure water flowing out of the two second filtration tanks 50 flows into the water storage tank 60 through a pair of sixth horizontal portions 2J of the filtration water channel 2.

[0129] In this way, when the water storage tank 60, the sixth horizontal portion 2J of the filtration water channel 2, and the second filtration tank 50 are filled with pure water, thereafter, the filtered water will flow into the adjustment storage tank 40 again, and the water level of the filtered water flowing into the adjustment storage tank 40 will rise (the water level will rise beyond the "upper end position line (which is the upper end position of the second filtration tank 50 and the upper end position of the water storage tank 60)" indicated by reference numeral 58).

[0130] Here, when the filtered water flows into the adjustment storage tank 40, the water level of the filtered water in the adjustment storage tank 40 will rise, but the "water level of the filtered water flowing into the adjustment storage tank 40" and the "water level of the rainwater flowing into the first filtration tank 20" maintain the same height.

[0131] Then, until the inflow of rainwater into the first filtration tank 20 stops, the filtered water continues to flow into the adjustment storage tank 40, and the water level of the filtered water in the adjustment storage tank 40 continues to rise.

[0132] However, if the water level of the filtered water in the adjustment storage tank 40 continues to rise (in other words, the water level of the rainwater that has flowed into the first filtration tank 20 continues to rise) and exceeds the height of the overflow water channel 70, the rainwater in the first filtration tank 20 will be drained to the outside, and thus the rise in the water level will stop.

[0133] After that, the water intake faucet 62 is opened to take pure water from the water storage tank 60.

[0134] Then, simultaneously with the intake of pure water, the pure water in the second filtration tank 50 naturally flows into the water storage tank 60. At the same time, the "filtered water in the adjustment storage tank 40" and the "filtered water flowing out of the first filtration tank 20" naturally flow into the second filtration tank 50. That is, when pure water is taken, according to the amount of water taken, pure water is introduced from the second filtration tank 50 to the water storage tank 60, and at the same time, filtered water is introduced from the adjustment storage tank 40 and the first filtration tank 20 to the second filtration tank 50.

[0135] In addition, during a period of low rainfall, in order to introduce all of the filtered water generated in the first filtration tank 20 only into the second filtration tank 50, the valve 3 for the adjustment storage tank may be closed so that the filtered water does not flow into the adjustment storage tank 40.

[0136] (Effect) Since the rainwater treatment system 1 of the present invention is provided with the adjustment storage tank 40, the storage capacity of the filtered water increases. That is, even if the water storage tank 60, which cannot be increased in height because it is necessary to ensure the water head pressure with the first filtration tank 20, becomes full, as long as the filtered water can be stored in the adjustment storage tank 40, the first filtration tank 20 does not need to discharge rainwater and can generate filtered water.

[0137] In addition, when pure water is taken from the water storage tank 60 of the rainwater treatment system 1 of the present invention, pure water is naturally supplied to the water storage tank 60 without the need for external power, and rainwater can be efficiently treated.

[0138] In addition, since the adjustment storage tank 40 does not need to consider the head pressure and can be enlarged in the height direction, it is possible to prevent the installation area of the rainwater treatment system 1 from becoming excessively large.

Explanation of Reference Numerals

[0139] 1 Rainwater treatment system 2 Filtration water channel 2A First horizontal part 2B First branch part 2C Second horizontal part 2D Vertical part 2E Third horizontal part 2F Fourth horizontal part 2G Drain vertical part 2H Second branch part 2I Fifth horizontal part 2J Sixth horizontal part 2K Drain faucet 3 Valve for adjustment storage tank 4 Valve for second filtration tank 5 Valve for water storage tank 6 Ground surface 7 Upper rain gutter 8 Lower rain gutter 10 Initial rainwater separation tank 11 First vertical water channel 12 Second vertical water channel 13 Third vertical water channel 14 Valve for first vertical water channel 15 Entrapped matter removal screen 16 Backflow prevention valve 17 Maintenance cover 20 First filtration tank 21 First filter 22 Internal piping 22A Connecting end 22B External communication end 23 Drain faucet 24 Foundation pedestal 25 Inspection cover 26 First filter insertion part 30 Stormwater drain 31 Ejection hole 40 Adjustment storage tank 41 Filtered water inlet / outlet 42 Drain faucet 43 Foundation pedestal 50 Second filtration tank 51 Second filter 52 Gap 53 Cavity 54 Filtered water inlet 55 Pure water outlet 56 Filtered water inlet side drain plug 57 Pure water outlet side drain plug 58 Upper end position line 60 Storage tank 61 Water intake path 62 Water intake faucet 63 Pure water inlet 70 Overflow water path 71 Circulation path 71A Valve for the first circulation path 71B Valve for the second circulation path

Claims

1. a first filtration tank having a first filter capable of filtering introduced rainwater to produce filtered water; an adjustment storage tank that is in communication with the first filtration tank and is capable of storing the filtrate generated by the first filtration tank; a water tank that is in communication with the first filtration tank and the adjustment storage tank, is capable of storing the filtered water, and has a maximum water level at which the filtered water can be stored that is lower than a maximum water level at which the filtered water can be stored in the adjustment storage tank. Stormwater treatment system.

2. A first waterway communicating with a predetermined gutter; a second waterway communicating with the first waterway at a first elevation and into which rainwater exceeding the first elevation is introduced; and a third waterway that communicates with the second waterway at a second height position and with the first filtration tank at a third height position that is higher than the second height position, and that introduces rainwater that exceeds the third height position into the first filtration tank. The storm water treatment system according to claim 1.

3. The height position of the adjustment tank at which the first filtration tank and the water tank communicate with each other is lower than the maximum water level that can be stored in the water tank. The storm water treatment system according to claim 1.

4. A second filtration tank having a second filter for further filtering the introduced filtrate water, The water tank is in communication with the first filtration tank and the adjustment tank via the second filtration tank. The storm water treatment system according to claim 1.

5. The height position of the adjustment storage tank at which the first filtration tank and the second filtration tank communicate with each other is lower than the maximum water level that can be introduced into the second filtration tank. The storm water treatment system according to claim 4.

6. The maximum water level that can be stored in the adjustment tank is the same as the maximum water level that can be introduced into the first filtration tank. The storm water treatment system according to claim 1.

7. A valve is provided to limit the introduction of the filtered water from the first filtration tank to the adjustment storage tank. The storm water treatment system according to claim 1.

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