Water purifying device

Abstract

[Problem] To provide a water purifying device capable of obtaining clean purified water without using a filter medium that reduces the amount of impurities. [Solution] A water purifying device comprises: a biological purifying device including a water storage tank, a biological filtration tank for biologically filtering water, a speed adjusting tank for adjusting the speed of water supplied to the biological filtration tank, and a clean water tank for storing the water supplied from the biological filtration tank and returning the biologically filtered water to the water storage tank; and a liquid feeding pump for feeding the water stored in the water storage tank to the speed adjusting tank, wherein water is circulated between the water storage tank and the biological purifying device.

Description

Water purification equipment

[0001] The present invention relates to a water purification device.

[0002] For example, in emergencies such as disasters or in emerging countries where water infrastructure is not well developed, it can be difficult to secure purified water that can be used for daily life, drinking water, etc. To address this problem, water purification devices have conventionally been used to purify raw water such as rainwater, river water, or pool water to obtain purified water. For example, Patent Document 1 discloses a water purification device that converts river or pool water into drinking water in emergencies such as earthquakes or fires.

[0003] Japanese Patent Application Laid-Open No. 2018-176088

[0004] However, the water purification device described in Patent Document 1 uses a reverse osmosis membrane water purifier to reduce impurities (hereinafter simply referred to as "impurities") such as bacteria and heavy metals contained in the raw water in order to purify the raw water to a quality level suitable for drinking water, domestic use, etc. In this case, for example, if the reverse osmosis membrane becomes clogged, the reverse osmosis membrane needs to be replaced. To replace the reverse osmosis membrane, for example, the reverse osmosis membrane water purifier must be transported to the manufacturer or a maintenance company, and the reverse osmosis membrane replacement must be performed at the manufacturer's factory, or a maintenance technician from the manufacturer must visit the site to replace the reverse osmosis membrane. This not only incurs high costs for transporting the reverse osmosis membrane water purifier and traveling costs for the maintenance technician, but also creates problems such as the water purification device being unable to operate during the maintenance period.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water purification device that can obtain clean purified water without using a filter material that reduces impurities.

[0006] In order to solve the above problems, according to one aspect of the present invention, there is provided a water purification system comprising a biological purification device having a water storage tank, a biological filtration tank for biologically filtering water, a speed adjustment tank for adjusting the speed of water supplied to the biological filtration tank, and a fresh water tank for storing water supplied from the biological filtration tank and returning the biologically filtered water to the water storage tank, and a liquid transfer pump for transferring water stored in the water storage tank to the speed adjustment tank, in which water is circulated between the water storage tank and the biological purification device.

[0007] In the following embodiments of this specification, "impurities" include, for example, general bacteria (bacteria, etc.), Escherichia coli, lead and its compounds, nitrite nitrogen, cyanide ions and cyanogen chloride, nitrate nitrogen, chloric acid, chloroacetic acid, chloroform, dichloroacetic acid, dibromochloromethane, bromic acid, total trihalomethanes, trichloroacetic acid, bromodichloromethane, bromoform, formaldehyde, zinc and its compounds, iron and its compounds, copper and its compounds, manganese and its compounds, chloride ions, aluminum and its compounds, sodium and its compounds, calcium, magnesium, cadmium and its compounds, mercury and its compounds, selenium and its compounds, lead and its compounds, arsenic and its compounds, hexavalent chromium compounds, fluorine and its compounds, boron and its compounds, carbon tetrachloride, anionic surfactants, nonionic surfactants, 1,4-dioxane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 2-methylisoborneol, dichloromethane, tetrachloroethylene. This includes, but is not limited to, trichloroethylene, geosmin, phenols, and benzene.

[0008] As described above, the water purifier of the present invention can obtain clean purified water without using a filter material that reduces impurities.

[0009] 2A and 2B are diagrams illustrating an example of the configuration of a water purification device according to a first embodiment; a cross-sectional view illustrating an example of the configuration of a biological purification device according to the first embodiment; a plan view illustrating an example of the configuration of a biological purification device according to the first embodiment; an enlarged cross-sectional view illustrating an enlarged region E of FIG. 2; a flowchart illustrating an example of a water purification method for the water purification device according to the first embodiment; a diagram illustrating an example of the configuration of a water purification device according to a second embodiment; a cross-sectional view illustrating an example of the configuration of a biological purification device according to the second embodiment; a cross-sectional view illustrating an example of the configuration of a UV irradiation device; a plan view of a UV irradiation device; a flowchart illustrating an example of a water purification method for the water purification device according to the second embodiment; a front view illustrating an example of the configuration of another water purification device according to the second embodiment; a side cross-sectional view illustrating an example of the configuration of another water purification device according to the second embodiment; a flowchart illustrating an example of a water purification method for the water purification device according to the second embodiment; a diagram illustrating an example of the configuration of a water purification device according to a third embodiment; a cross-sectional view illustrating an example of the configuration of a biological purification device according to the third embodiment; a flowchart illustrating an example of a water purification method for the water purification device according to the third embodiment; a table illustrating the results of testing the quality of rainwater stored in a water storage tank before purification; a table illustrating the results of testing the quality of purified water that was finally stored in the fresh water tank after circulating water multiple times between a water storage tank containing rainwater and a biological purification device.

[0010] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions. The drawings may be shown schematically to facilitate understanding. Furthermore, the scope of the present invention is not limited to the following exemplary embodiments unless otherwise specified to limit the present invention.

[0011] 1. Embodiments <First embodiment> [Configuration of water purification device] Fig. 1 is a diagram showing an example of the configuration of a water purification device 100 according to this embodiment. The water purification device 100 has a water storage tank 10, a liquid delivery pump 20, a renewable energy power source 30, and an biological purification device 40.

[0012] (Water Storage Tank) The water storage tank 10 is connected to a pipe p3 and hoses H2 and H3. The pipe p3 is connected to a rough filtration tank F. The rough filtration tank F is connected to a pipe p2. The pipe p2 is connected to a diverter S. The diverter S diverts rainwater flowing through the vertical rain barrel pipe p1 to the rough filtration tank F via the pipe p2. The rough filtration tank F removes foreign matter such as gravel and vegetation from the rainwater, and supplies the rainwater from which the foreign matter has been removed to the water storage tank 10 via the pipe p3.

[0013] The water storage tank 10 has an overflow pipe 11, an air intake 12, and a strainer 13. The overflow pipe 11 discharges water from the water storage tank 10 when the water level in the water storage tank 10 reaches a predetermined level or higher.

[0014] When water is supplied to the water storage tank 10, the pressure inside the water storage tank 10 rises, making it difficult for water to enter the water storage tank 10, but the air intake 12 releases the pressure, allowing water to flow smoothly into the water storage tank 10.

[0015] The strainer 13 is connected to a pipe p4 provided with a valve V1. The strainer 13 removes solid components such as garbage contained in the water supplied from the water storage tank 10, and supplies the water from which the solid components have been removed to the liquid feed pump 20 via the pipe p4. The valve V1 is a normal valve that switches the pipe p4 between open and closed.

[0016] (Liquid feed pump) The liquid feed pump 20 is connected to the pipe p4 and the hose H1. The liquid feed pump 20 feeds water supplied from the water storage tank 10 to the biological purification device 40 via the hose H1. The liquid feed pump 20 may be, for example, a positive displacement or non-positive displacement liquid feed pump, and the type thereof is not particularly limited.

[0017] (Renewable Energy Power Source) The renewable energy power source 30 has a solar panel 31 and a battery 32. The solar panel 31 is connected to the battery 32 via a cord C2 and is a power generation device that generates electric power using solar energy. The battery 32 stores the electric power generated by the solar panel 31 and supplies the electric power to the liquid feed pump 20 via a cord C1. Note that in the renewable energy power source 30 according to this embodiment, a power generation device that uses renewable energy other than solar energy may be used instead of the solar panel 31. Examples of such renewable energy include wind power, geothermal power, hydroelectric power, and biomass.

[0018] (Biological Purification Device) The biological purification device 40 has a water inlet P1, an overflow port P2, a drain port P3, and a water faucet V3. The water inlet P1 is provided with a speed control valve V2. The speed control valve V2 is connected to a hose H1. The overflow port P2 is connected to a hose H2. The drain port P3 is connected to a hose H3.

[0019] Fig. 2 is a cross-sectional view showing an example of the configuration of the biological purification device 40, and Fig. 3 is a plan view showing an example of the configuration of the biological purification device 40. As shown in Fig. 2, the biological purification device 40 has a biological filtration tank 41, a speed adjustment tank 42, and a fresh water tank 43. The biological filtration tank 41, the speed adjustment tank 42, and the fresh water tank 43 are made of, for example, colorless or black acrylic plates.

[0020] In the following description, mutually orthogonal X-axis, Y-axis, and Z-axis are defined. The X-axis, Y-axis, and Z-axis are three mutually orthogonal axial directions, and are common to Figures 2 to 4, 7 to 9, 11, 12, and 15 of this specification. As illustrated in Figure 2, one direction along the X-axis as viewed from an arbitrary point is referred to as the X1 direction, and the direction opposite to the X1 direction is referred to as the X2 direction. The X-axis direction is a direction that includes both the X1 direction and the X2 direction. Similarly, mutually opposite directions along the Y-axis from an arbitrary point are referred to as the Y1 direction and the Y2 direction. The Y-axis direction is a direction that includes both the Y1 direction and the Y2 direction. Furthermore, mutually opposite directions along the Z-axis from an arbitrary point are referred to as the Z1 direction and the Z2 direction. The Z-axis direction is a direction that includes both the Z1 direction and the Z2 direction. Furthermore, the X-Y plane including the X-axis and Y-axis corresponds to a horizontal plane. The Z-axis is an axis that extends vertically.

[0021] The biological filtration tank 41 is a septic tank that purifies water through slow filtration and includes a biological septic tank 411 and a water storage tank 412. A biological filtration material is deposited in the biological septic tank 411. The biological filtration material includes, for example, a gravel layer 411a, a sand layer 411b, and a biological filtration membrane 411c. The biological filtration membrane 411c is a natural filtration membrane formed spontaneously on the sand layer 411b by organisms such as algae and microorganisms. Examples of such organisms include merocrypha, cyclodactyla, cyclodactyla, cyclodactyla, paramecium, and earthworms. The particle size of the sand constituting the sand layer 411b is preferably 0.30 mm to 0.45 mm, and more preferably 0.35 mm, in order to achieve good filtration performance.

[0022] Purified water produced by biological filtration of water in the biological purification tank 411 is supplied to the water storage tank 412 via through-holes 41H provided in the bottom of the biological purification tank 411. The water storage tank 412 stores the purified water supplied from the biological purification tank 411. When the water level of the purified water reaches or exceeds the position of the inlet 50a in the Z-axis direction, the purified water is supplied to the fresh water tank 43 through the downcomer 50.

[0023] Figure 4 is an enlarged cross-sectional view of region E in Figure 2. The speed adjustment tank 42 is a tank for storing water supplied from the liquid supply pump 20 and adjusting the speed of the water supplied to the biological purification tank 411. The speed adjustment tank 42 has a speed adjustment unit 421.

[0024] As shown in Fig. 4, the speed adjustment unit 421 has an orifice plate 421a and a fixing portion 421b. The orifice plate 421a is provided on the partition wall W that separates the biological purification tank 411 and the speed adjustment tank 42. The fixing portion 421b is a plate material for fixing the orifice plate 421a to the partition wall W. For example, as shown in Fig. 4, a screw B penetrates the fixing portion 421b and the orifice plate 421a, and the portion of the screw B that protrudes from the orifice plate 421a screws into the partition wall W, thereby fixing the orifice plate 421a to the partition wall W.

[0025] When the water level supplied from the liquid feed pump 20 to the speed adjustment tank 42 reaches or exceeds the position of the orifice hole h2 of the orifice plate 421a in the Z-axis direction, the water is supplied to the biological septic tank 411 through the through-hole h1 of the fixing portion 421b, the orifice hole h2, and the opening h3 of the partition wall W. In this embodiment, the position of the orifice hole h2 in the Z-axis direction is set to an appropriate position between the surface of the biological filtration membrane 411c and the overflow port P2 so that the speed of the water passing through the biological filtration membrane 411c, or the gravel layer 411a, the sand layer 411b, and the biological filtration membrane 411c, is, for example, 5 m / day or more and 15 m / day or less. In this embodiment, the water speed is multiplied by the planar area of ​​the biological septic tank 411 (the surface area of ​​the surface facing the Z2 direction of the biological filtration membrane 411) to calculate the amount of purified water passing through the biological filtration material per day.

[0026] The clean water tank 43 is a water tank that stores the purified water supplied from the water storage tank 412. When the water level of the purified water reaches or exceeds the position of the drain outlet P3 in the Z-axis direction, the purified water is returned to the water storage tank 10 via the hose H3.

[0027] [Operation of the Water Purification Device] The water purification device 100 according to this embodiment circulates water between the water storage tank 10 and the biological purification device 40. Specifically, as shown in the flowchart of FIG. 5 , the water purification device 100 executes steps St1 and St2 described below, and then repeatedly executes steps St3 to St6 described below. As a result, as described in the "Example" section below, the water finally stored in the fresh water tank 43 after circulation can be purified to a quality level suitable for drinking water, domestic use, and the like. Therefore, according to the present invention, clean purified water can be obtained from rainwater without using a filter material such as a reverse osmosis membrane. Therefore, compared to conventional water purification devices that require filter material such as a reverse osmosis membrane or hollow fiber membrane to reduce impurities, the water purification device 100 does not require processing such as replacing the filter material, making it easier to maintain and manage than the water purification device. Furthermore, the water purification device 100 can be maintained and managed without requiring more advanced skills and knowledge than the conventional water purification device (Advantage 1).

[0028] In addition, previous water purification devices that required filter media such as reverse osmosis membranes or hollow fiber membranes have a filter media lifespan that corresponds to the amount of water to be physically filtered, and there is a limit to the amount of water that can be physically filtered.However, the water purification device 100 of this embodiment does not have such a filter media lifespan, so there is also the advantage (advantage 2) that the water can be purified along with the water storage tank.

[0029] Furthermore, by installing the water purification device 100 of this embodiment in each household, there is no need to install the water purification plant itself or lay water supply pipes from the water purification plant to each household, which has the advantage (advantage 3) of eliminating the need to develop a large-scale water supply infrastructure.

[0030] Additionally, in the water purification device 100 according to this embodiment, the power source that supplies power to the liquid feed pump 20 is a renewable energy power source 30. As a result, the installation location of the water purification device 100 is not limited to being near a power supply source such as a power supply facility. Therefore, the water purification device 100 has the advantage (advantage 4) that the purified water can be obtained at any desired location without being limited to a specific location.

[0031] Furthermore, as described above, the water purification device 100 of this embodiment has the advantage (advantage 5) that water is constantly circulated between the water storage tank 10 and the biological purification device 40, thereby preventing the biological filtration membrane 411c from drying up during the process of purifying rainwater into purified water.

[0032] Furthermore, with the water purification device 100 according to this embodiment, by sufficiently circulating water between the water storage tank 10 and the biological purification device 40, not only the water in the fresh water tank 43 but also the water that ultimately accumulates in the water storage tank 10 after circulation can be purified to a quality level suitable for drinking water, domestic use, etc. This also has the advantage (advantage 6) of being able to secure purified water from the water storage tank 10 even if the purified water accumulated in the fresh water tank 43 dries up.

[0033] The multiple advantages (advantages 1 to 6) described above are particularly useful, for example, in cases where water infrastructure is not functioning due to a disaster or in emerging countries where water infrastructure is not well developed.

[0034] (Step St1: Storing rainwater in the water storage tank) The rainwater from which foreign matter has been removed by the coarse filtration tank F is stored in the water storage tank 10 until the water storage tank 10 is full or the water level is low enough not to overflow from the overflow pipe 11. In step St1, the valve V1 is closed and the liquid feed pump 20 is stopped.

[0035] (Step St2: Starting up the liquid feed pump) The supply of rainwater to the water storage tank 10 is stopped, and the valve V1 is opened. Next, the liquid feed pump 20 is started up.

[0036] (Step St3: Sending Liquid to Speed ​​Adjustment Tank) The liquid feed pump 20 sends the water from which solid components have been removed by the strainer 13 to the speed adjustment tank 42. At this time, the speed of the water flowing into the speed adjustment tank 42 is controlled by the speed adjustment valve V2 to, for example, 5 m / day or more and 30 m / day or less. The water supplied to the speed adjustment tank 42 is supplied to the biological purification tank 411 when its water level reaches or exceeds the position of the orifice hole h2 in the Z-axis direction, and is returned to the water storage tank 10 via the hose H2 when its water level reaches or exceeds the position of the overflow port P2 in the Z-axis direction. This maintains the water level in the speed adjustment tank 42 at or below a predetermined level.

[0037] (Step St4: Biological Filtration) The water supplied to the biological purification tank 411 is biologically filtered by the biological filtering material deposited in the biological purification tank 411. Purified water produced by the biological filtration of the water is supplied to the water storage tank 412 via the through-hole 41H.

[0038] (Step St5: Supplying purified water to the clean water tank) When the water level supplied to the water storage tank 412 reaches or exceeds the position in the Z-axis direction of the inlet 50a of the downcomer pipe 50, the purified water passes through the downcomer pipe 50 and is supplied to the clean water tank 43.

[0039] (Step St6: Returning purified water to the water storage tank) The clean water tank 43 stores the purified water supplied from the water storage tank 412. When the water level of the purified water reaches or exceeds the position of the drain outlet P3 in the Z-axis direction, the purified water is returned to the water storage tank 10 via the hose H3.

[0040] Second Embodiment Next, a second embodiment of the present invention will be described. In the following description of the second embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0041] 6 is a diagram showing an example of the configuration of a water purification device 200 according to the second embodiment. The water purification device 200 includes a water storage tank 10, a liquid delivery pump 20, a renewable energy power supply 310, an biological purification device 410, and a UV irradiation device 80.

[0042] (Renewable Energy Power Source) The renewable energy power source 310 has a solar panel 31 and a battery 32. The battery 32 stores the power generated by the solar panel 31 and supplies the power to the liquid feed pump 20 via a cord C1 and to a UV lamp 83 (described later) via a cord C3.

[0043] (Biological Purification Device) The biological purification device 410 has water inlets P1 and P5, an overflow outlet P2, drain outlets P3 and P4, and a water faucet V3. The drain outlet P3 is connected to a hose H3. The hose H3 is connected to the water storage tank 10. The drain outlet P4 is connected to a hose H4. The hose H4 is connected to the water inlet P5.

[0044] Fig. 7 is a cross-sectional view showing an example configuration of a biological purification device 410 according to the second embodiment. As shown in Fig. 7, the biological purification device 410 has a biological filtration tank 41, a speed adjustment tank 42, a fresh water tank 43, and a secondary filtration tank 44. The secondary filtration tank 44 is made of, for example, a colorless or black acrylic plate.

[0045] The secondary filtration tank 44 has an activated carbon filtration tank 441 and a sand filtration tank 442. The activated carbon filtration tank 441 contains activated carbon Ab. The activated carbon filtration tank 441 is a water tank that filters purified water supplied from the water storage tank 412 through activated carbon and stores secondary purified water produced by the activated carbon filtration of the purified water. When the water level of the secondary purified water reaches or exceeds the height of the activated carbon filtration tank 441 in the Z-axis direction, the secondary purified water exceeds the activated carbon filtration tank 441 and is supplied to the sand filtration tank 442.

[0046] The sand filtration tank 442 includes a sedimentation tank 4421 and a water storage tank 4422. Sand filter material 442a is deposited in the sedimentation tank 4421. The sand filter material 442a is a sand reservoir. Tertiary purified water produced by sand filtering the secondary purified water in the sedimentation tank 4421 is supplied to the water storage tank 4422 through a through-hole 45H provided at the bottom of the sedimentation tank 4421. The water storage tank 4422 stores the tertiary purified water supplied from the sedimentation tank 4421. When the water level of the tertiary purified water reaches or exceeds the position of the drain outlet P4 in the Z-axis direction, the tertiary purified water is supplied to the UV irradiation device 80 via the hose H4 and the water supply port P5. Note that the particle size of the sand constituting the sand filtration material 442a is preferably 0.30 mm or more and 0.45 mm or less, and more preferably 0.35 mm, from the viewpoint of exhibiting good filtering ability.

[0047] (UV irradiation device) Fig. 8 is a cross-sectional view showing an example of the configuration of a UV irradiation device 80, and Fig. 9 is a plan view of the UV irradiation device 80. The UV irradiation device 80 is disposed in the fresh water tank 43 and has a rubber tube 81, a supply pipe 82, and a UV lamp 83. As shown in Fig. 9, the water supply port P5 according to the second embodiment is a pipe that passes through the fresh water tank 43 and bends in the X2 direction, and is supported by the fresh water tank 43.

[0048] The supply pipe 82 is a pipe extending in the X-axis direction and contains a UV lamp 83. The supply pipe 82 is connected to the water supply port P5 via a rubber tube 81. A gap 82S is formed between the inner circumferential surface of the supply pipe 82 and a portion of the UV lamp 83 other than the end located in the X2 direction. As shown in Figures 8 and 9, this end is supported by the inner circumferential surface of the supply pipe 82. The supply pipe 82 is not particularly limited, but may be, for example, a stainless steel pipe.

[0049] The tertiary purified water supplied from the water storage tank 4422 to the UV irradiation device 80 is irradiated with UV while flowing through the gap 82S in the X2 direction, and is then supplied into the clean water tank 43 through the outlet 82H. As a result, quaternary purified water, which is tertiary purified water that has been UV-sterilized, is stored in the clean water tank 43. When the water level of the quaternary purified water reaches or exceeds the position of the drain outlet P3 in the Z-axis direction, the quaternary purified water is returned to the water storage tank 10 through the hose H3.

[0050] [Operation of the Water Purification Device] The water purification device 200 according to the second embodiment circulates water between the water storage tank 10 and the biological purification device 40. Specifically, as shown in the flowchart of FIG. 10 , the water purification device 200 executes the following steps St21 and St22, and then repeatedly executes the following steps St23 to St28. As a result, as described in the "Example" section below, the water finally stored in the fresh water tank 43 after circulation can be purified to a water quality level suitable for drinking water, domestic use, and the like. Therefore, the water purification device 200 according to the second embodiment achieves advantages 1 to 6 described in the first embodiment. In particular, the water purification device 200 according to the second embodiment filters the purified water through activated carbon and sand filtration, and then further sterilizes it with UV light. Therefore, there is an advantage (advantage 7) that the water finally stored in the fresh water tank 43 after circulation can be purified to a level suitable for drinking water, domestic use, and the like.

[0051] (Step St21: Storing rainwater in the water storage tank) The rainwater from which foreign matter has been removed by the coarse filtration tank F is stored in the water storage tank 10 until the water storage tank 10 is full or the water level is low enough not to overflow from the overflow pipe 11. In step St21, the valve V1 is closed and the liquid feed pump 20 is stopped.

[0052] (Step St22: Start of Liquid Feed Pump) The supply of rainwater to the water storage tank 10 is stopped, and the valve V1 is opened. Next, the liquid feed pump 20 is started.

[0053] (Step St23: Sending Liquid to Speed ​​Adjustment Tank) The liquid feed pump 20 sends the water, from which solid components have been removed by the strainer 13, from the water storage tank 10 to the speed adjustment tank 42. At this time, the speed of the water supplied to the speed adjustment tank 42 is controlled by the speed adjustment valve V2 to, for example, 5 m / day or more and 30 m / day or less. The water supplied to the speed adjustment tank 42 is supplied to the biological purification tank 411 when its water level reaches or exceeds the position of the orifice hole h2 in the Z-axis direction, and is returned to the water storage tank 10 via the hose H2 when its water level reaches or exceeds the position of the overflow port P2 in the Z-axis direction.

[0054] (Step S24: Biological filtration) The water supplied to the biological purification tank 411 is biologically filtered by the biological filtering material deposited in the biological purification tank 411. Purified water produced by the biological filtration of the water is supplied to the water storage tank 412 via the through-hole 41H.

[0055] (Step S25: Activated carbon filtration) When the water level of the purified water supplied to the water storage tank 412 reaches or exceeds the position in the Z-axis direction of the inlet 50a of the downcomer pipe 50, it passes through the downcomer pipe 50 and is supplied to the activated carbon filtration tank 441. The activated carbon filtration tank 441 performs activated carbon filtration of the purified water supplied from the water storage tank 412. When the water level of the secondary purified water generated by the activated carbon filtration of the purified water reaches or exceeds the height of the activated carbon filtration tank 441 in the Z-axis direction, it passes over the activated carbon filtration tank 441 and is supplied to the sedimentation tank 4421.

[0056] (Step St26: Sand Filtration) The secondary purified water supplied to the sedimentation tank 4421 is sand filtered by the sand filter material 442a deposited in the sedimentation tank 4421. Tertiary purified water produced by sand filtration of the secondary purified water is supplied to the water storage tank 4422 via the through-hole 45H.

[0057] (Step St27: UV Sterilization) When the water level of the tertiary purified water supplied to the water tank 4422 reaches or exceeds the position of the drain outlet P4 in the Z-axis direction, it is supplied to the UV irradiation device 80 via the hose H4. The tertiary purified water supplied to the UV irradiation device 80 is UV sterilized by being irradiated with UV while flowing through the gap 82S in the X2 direction, and becomes quaternary purified water. The quaternary purified water is supplied into the fresh water tank 43 via the outlet 82H.

[0058] (Step St28: Returning the fourth purified water to the water storage tank) The clean water tank 43 stores the fourth purified water supplied from the UV irradiation device 80. When the water level of the fourth purified water reaches or exceeds the position of the drain outlet P3 in the Z-axis direction, the fourth purified water is returned to the water storage tank 10 via the hose H3.

[0059] Next, the configuration and operation of another water purification device according to a second embodiment of the present invention will be described. In this description, the same components as those of the water purification devices 100 and 200 according to the first and second embodiments are denoted by the same reference numerals, and their description and illustration may be omitted or simplified.

[0060] [Configuration of Water Purification Device] Another water purification device according to the second embodiment includes a water storage tank 10 , a liquid feed pump 20 , a renewable energy power supply 310 that supplies power to the liquid feed pump 20 , and an biological purification device 610 .

[0061] (Biological purification device) Fig. 11 is a front view showing an example of the configuration of another biological purification device 610 according to the second embodiment, and Fig. 12 is a side cross-sectional view showing the example of the configuration of the biological purification device 610. The biological purification device 610 has a biological filtration tank 61, a speed adjustment tank 62, a fresh water tank 63, and a secondary filtration tank 64.

[0062] The biological filtration tank 61 is a septic tank that purifies water through slow filtration and includes a biological septic tank 611 and a water storage tank 612. A biological filtration material is deposited in the biological septic tank 611. The biological filtration material includes, for example, a gravel layer 611a, a sand layer 611b, and a biological filtration membrane 611c. The biological filtration membrane 611c is a natural filtration membrane formed spontaneously on the sand layer 611b by organisms such as algae and microorganisms. Examples of such organisms include merocrypha, cyclodactyla, cephalopoda, cylindrica, paramecium, and earthworms. The particle size of the sand constituting the sand layer 611b is preferably 0.30 mm to 0.45 mm, and more preferably 0.35 mm, from the viewpoint of achieving good filtration performance.

[0063] Purified water produced by biological filtration of water in the biological purification tank 611 is supplied to a water storage tank 612. The water storage tank 612 stores the purified water supplied from the biological purification tank 611. As shown in FIG. 12 , the water storage tank 612 is connected to a guide pipe p5 formed by connecting multiple pipes, and supplies the purified water to a secondary filtration tank 64 (activated carbon filtration tank 641) via the guide pipe p5. The biological filtration tank 61 is a container formed by, for example, injection molding. Therefore, the biological filtration tank 61 is made of, for example, synthetic resin.

[0064] The speed adjustment tank 62 is connected to the biological purification tank 611 and has a water supply port P8 and an overflow port P9. The water supply port P8 is connected to a hose h2 via a speed adjustment valve V5. The hose h2 is connected to the liquid feed pump 20. The overflow port P9 is connected to a hose h1. The hose h1 is connected to the water storage tank 10.

[0065] The speed adjustment tank 62 is a tank for storing water supplied from the liquid supply pump 20 and adjusting the speed of the water supplied to the biological purification tank 611. Specifically, the speed adjustment tank 62 adjusts the speed of the water passing through the biological filtration membrane 611c, or the gravel layer 611a, the sand layer 611b, and the biological filtration membrane 611c, to be 5 m / day or more and 15 m / day or less.

[0066] The speed adjustment tank 62 is a container that is constructed separately from the biological purification tank 611 and is disposed in the Y1 direction from the biological purification tank 611. The speed adjustment tank 62 is obtained by, for example, injection molding, and is therefore made of, for example, synthetic resin.

[0067] The secondary filtration tank 64 has an activated carbon filtration tank 641 and a sand filtration tank 642. The activated carbon filtration tank 641 is connected to the sand filtration tank 642 (sediment layer 6421) and the guide pipe p5, and has an overflow port P10. The overflow port P10 is connected to a hose h4. The hose h4 is connected to a Y-type joint y (a three-way joint). The Y-type joint y is connected to a hose h5 and a hose h6. The hose h6 is connected to the water storage tank 10.

[0068] The activated carbon filtration tank 641 contains activated carbon Ab. The activated carbon filtration tank 641 is a water tank that filters purified water supplied from the water storage tank 612 through activated carbon and stores secondary purified water produced by the activated carbon filtration of the purified water. When the secondary purified water reaches a predetermined water level in the activated carbon filtration tank 641, it is supplied to the sand filtration tank 642 (sedimentation tank 6421).

[0069] The activated carbon filtration tank 641 is a container that is configured separately from the sand filtration tank 642 and is disposed in the Y1 direction relative to the sand filtration tank 642. The activated carbon filtration tank 641 is obtained by, for example, injection molding, and is therefore made of, for example, synthetic resin.

[0070] The sand filtration tank 642 has a deposition tank 6421 and a water storage tank 6422. Sand filter material 642a is deposited in the deposition tank 6421. The sand filter material 642a is a sand reservoir. Tertiary purified water produced by sand filtration of the secondary purified water in the deposition tank 6421 is supplied from the deposition tank 6421 to the water storage tank 6422. From the viewpoint of achieving good filtering ability, the particle size of the sand constituting the sand filter material 642a is preferably, for example, 0.30 mm or more and 0.45 mm or less, and more preferably 0.35 mm.

[0071] The water storage tank 6422 stores the tertiary purified water supplied from the sedimentation tank 6421. As shown in FIG. 11 , the water storage tank 6422 is connected to a guide pipe p6. The guide pipe p6 is connected to a hose h3. The hose h3 is connected to the fresh water tank 63. When the level of the tertiary purified water in the water storage tank 6422 reaches a predetermined level, the tertiary purified water is supplied to the fresh water tank 63 via the guide pipe p6 and the hose h3. The sand filter tank 642 is a container formed, for example, by injection molding. Therefore, the sand filter tank 642 is made of, for example, synthetic resin.

[0072] The clean water tank 63 is a water tank that stores the tertiary purified water supplied from the water storage tank 6422. As shown in FIG. 12 , the clean water tank 63 is connected to the water supply valve V7 and the guide pipe p7, and has an overflow port P11. The guide pipe p7 is connected to a hose h7. The hose h7 is connected to a UV irradiation device 80. The UV irradiation device 80 according to another water purification device of the second embodiment is connected to the water supply valve V6 via an outlet 62H. The overflow port P11 is connected to a hose h5.

[0073] When the level of the tertiary purified water reaches a predetermined level in the fresh water tank 63, the tertiary purified water is supplied to the UV irradiation device 80 via the guide pipe p7 and the hose h7. Furthermore, when the level of the tertiary purified water reaches or exceeds the position of the overflow port P11 in the Z-axis direction, the tertiary purified water is returned to the water storage tank 10 via the hose H5, the Y-type joint y, and the hose h6. The fresh water tank 63 is a container formed, for example, by injection molding. Therefore, the fresh water tank 63 is made of, for example, synthetic resin.

[0074] [Operation of the Water Purifier] The water purification device according to the second embodiment circulates water between the water storage tank 10 and the biological purification device 610. Specifically, as shown in the flowchart of FIG. 13 , when the water supply valve V6 is closed, the water purification device executes steps St41 and St42 below, and then repeatedly executes steps St43 to St47 and St50 below. As a result, as described in the "Example" section below, the water finally stored in the fresh water tank 63 after circulation can be purified to a quality level suitable for drinking water, domestic use, and the like. Therefore, the water purification device according to the second embodiment achieves advantages 1 to 6 described in the first embodiment. In particular, the water purification device can perform activated carbon filtration and sand filtration of purified water, followed by UV sterilization. Therefore, advantage 7 described above can also be achieved. Note that the flowchart shown in FIG. 13 is merely an example, and the operation of the water purification device according to the second embodiment is not limited to the operations shown in the flowchart.

[0075] (Step St41: Storing rainwater in the water storage tank) The rainwater from which foreign matter has been removed by the coarse filtration tank F is stored in the water storage tank 10 until the water storage tank 10 is full or the water level is low enough not to overflow from the overflow pipe 11. In step St41, the valve V1 is closed and the liquid feed pump 20 is stopped.

[0076] (Step St42: Start the liquid feed pump) The supply of rainwater to the water storage tank 10 is stopped, and the valve V1 is opened. Next, the liquid feed pump 20 is started.

[0077] (Step St43: Sending Liquid to Speed ​​Adjustment Tank) The liquid feed pump 20 sends water, from which solid components have been removed by the strainer 13, from the water storage tank 10 to the speed adjustment tank 62. At this time, the speed of the water flowing into the speed adjustment tank 62 is controlled by the speed adjustment valve V5 to, for example, between 5 m / day and 30 m / day. The water supplied to the speed adjustment tank 62 is supplied to the biological purification tank 611, and when it reaches or exceeds the position of the overflow port P9 in the Z-axis direction, it is returned to the water storage tank 10 via the hose h1.

[0078] (Step S44: Biological filtration) The water supplied to the biological purification tank 611 is biologically filtered by the biological filtering material deposited in the biological purification tank 611. Purified water produced by the biological filtration of the water is supplied to the water storage tank 612.

[0079] (Step S45: Activated carbon filtration) The purified water supplied to the water storage tank 612 is supplied to the activated carbon filtration tank 641 via the guide pipe p5. The activated carbon filtration tank 641 performs activated carbon filtration on the purified water supplied from the water storage tank 612. Secondary purified water generated by the activated carbon filtration of the purified water is supplied to the sedimentation tank 6421.

[0080] (Step St46: Sand Filtration) The secondary purified water supplied to the sedimentation tank 6421 is sand filtered by the sand filter material 642a deposited in the sedimentation tank 6421. Tertiary purified water produced by sand filtration of the secondary purified water is supplied to the water storage tank 6422.

[0081] (Step St47: UV Sterilization) The tertiary purified water supplied to the water tank 6422 is supplied to the clean water tank 63 via the guide pipe p6 and the hose h3. The tertiary purified water supplied to the clean water tank 63 is supplied to the UV irradiation device 80 via the guide pipe p7 and the hose H4. The tertiary purified water supplied to the UV irradiation device 80 is UV sterilized by being irradiated with UV while flowing through the gap 82S in the X2 direction, and becomes quaternary purified water.

[0082] (Step St49: Discharge of Quaternary Purified Water) If the water supply valve V6 is in an open state (YES in step St48), the quaternary purified water is discharged from the UV irradiation device 80 to the outside of the biological purification device 610.

[0083] (Step St50: Returning tertiary purified water to the water storage tank) When the water supply valve V6 is in a closed state (NO in step St48), if the water level of the tertiary purified water reaches or exceeds the position in the Z-axis direction of the overflow port P11 due to the water supply valve V6 being closed, the tertiary purified water is returned to the water storage tank 10 via hoses H5 and H6.

[0084] Third Embodiment Next, a third embodiment of the present invention will be described. In the following description of the third embodiment, the same components as those in the first and second embodiments will be denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0085] 14 is a diagram showing an example of the configuration of a water purification device 300 according to the third embodiment. The water purification device 300 includes a water storage tank 10, a liquid delivery pump 20, a renewable energy power supply 320, an biological purification device 510, and a UV irradiation device 80.

[0086] (Renewable Energy Power Source) The renewable energy power source 320 has a solar panel 31 and a battery 32. The battery 32 stores the power generated by the solar panel 31 and supplies the power to the liquid feed pump 20 via cord C1, to the UV lamp 83 via cord C3, and to the return pump 511 via cord C4.

[0087] (Biological Purification Device) The biological purification device 510 has water inlets P1 and P7, an overflow port P2, drain outlets P4 and P6, a water supply valve V3, and a return pump 511. The drain outlet P4 is connected to a hose H4. The hose H4 is connected to the water storage tank 10. The drain outlet P6 is connected to the return pump 511. The return pump 511 is connected to a hose H5. The hose H5 is connected to a T-joint t. The T-joint t is connected to the UV irradiation device 80 in the clean water tank 43 and to the hose H6. A valve v is provided at the connection between the T-joint t and the UV irradiation device 80 (see FIG. 15 ). The valve v controls the speed of the tertiary purified water flowing from the T-joint t to the UV irradiation device 80. The hose H6 is connected to the water inlet P7 via a speed adjustment valve V4.

[0088] The return pump 511 sends the tertiary purified water to the T-joint t via the hose H5. The tertiary purified water branches at the T-joint t, with a portion of the tertiary purified water being sent to the UV irradiation device 80 in the clean water tank 43 and another portion being returned to the biological purification tank 411. The return pump 511 may be, for example, a positive displacement or non-positive displacement liquid pump, and the type thereof is not particularly limited.

[0089] Figure 15 is a cross-sectional view showing an example configuration of a biological purification device 510 according to the third embodiment. The biological purification device 510 has a biological filtration tank 41, a speed adjustment tank 42, a fresh water tank 43, and a secondary filtration tank 44. As shown in Figure 15, the biological purification device 510 according to the third embodiment has the fresh water tank 43 provided between the biological filtration tank 41 and the secondary filtration tank 44.

[0090] The clean water tank 43 according to the third embodiment houses a UV irradiation device 80 and has a guide pipe 70. The guide pipe 70 extends in the X-axis direction and is cylindrical. The guide pipe 70 guides the purified water supplied from the downcomer 50 to the activated carbon filtration tank 441.

[0091] The activated carbon filtration tank 441 according to the third embodiment is a water tank that filters purified water supplied from the water tank 412 using activated carbon and stores secondary purified water produced by filtering the purified water using activated carbon.

[0092] The deposition layer 4421 according to the third embodiment has a liquid level detection sensor 451S. The liquid level detection sensor 451S is electrically connected to the liquid feed pump 20. The liquid level detection sensor 451S is, for example, a float switch, but is not limited to this and other types may be adopted.

[0093] The liquid level detection sensor 451S detects the liquid level of the secondary purified water supplied to the deposition tank 4421 and outputs a stop signal to the liquid feed pump 20 to stop the liquid feed pump 20. When the liquid feed pump 20 stops, the water purification device 300 performs only the second circulation out of the first circulation and second circulation described below. On the other hand, the liquid level detection sensor 451S restarts the liquid feed pump 20 when the liquid level of the secondary purified water in the deposition tank 4421 falls below a predetermined water level.

[0094] (UV Irradiation Device) The UV irradiation device 80 according to the third embodiment is disposed in the clean water tank 43 and is supported on the inner surface of the clean water tank 43 facing the Y2 direction. The tertiary purified water supplied from the return pump 511 to the UV irradiation device 80 is sterilized by UV irradiation while flowing through the gap 82S, and becomes quaternary purified water. The quaternary purified water is supplied into the clean water tank 43 via the outlet 82H.

[0095] [Operation of the Water Purification Device] The water purification device 300 according to the third embodiment executes a first circulation (indicated by the solid arrows in FIG. 15 ) in which water circulates between the water storage tank 10 and the biological purification device 40, and a second circulation (indicated by the dotted arrows in FIG. 15 ) in which water circulates within the biological purification device 40. Specifically, as shown in the flowchart in FIG. 16 , the water purification device 300 executes the following steps St31 and St32, followed by the first circulation in which the following steps St33 to St36 are repeated, and the second circulation in which the following steps St34, St35, and St37 to St40 are repeated. As a result, as described in the "Example" section below, the water finally stored in the fresh water tank 43 after circulation can be purified to a quality level suitable for drinking water, domestic use, and the like. The water purification device 300 according to the third embodiment achieves advantages 1 to 7 described in the first and second embodiments. In particular, the water purification device 300 of the third embodiment continues to perform the second circulation even if the first circulation stops due to some reason causing the liquid feed pump 20 to malfunction. This ensures that water is constantly circulating within the biological purification device 510, thereby preventing deterioration of water quality.

[0096] (Step St31: Storing rainwater in the water storage tank) The rainwater from which foreign matter has been removed by the coarse filtration tank F is stored in the water storage tank 10 until the water storage tank 10 is full or the water level is low enough not to overflow from the overflow pipe 11. In step St31, the valve V1 is closed and the liquid feed pump 20 is stopped.

[0097] (Step St32: Start the Liquid Feed Pump) The supply of rainwater to the water storage tank 10 is stopped, and the valve V1 is opened. Next, the liquid feed pump 20 is started.

[0098] (Step St33: Sending Liquid to Speed ​​Adjustment Tank) The liquid feed pump 20 sends the water, from which solid components have been removed by the strainer 13, from the water storage tank 10 to the speed adjustment tank 42. At this time, the speed of the water supplied to the speed adjustment tank 42 is controlled by the speed adjustment valve V2 to, for example, 5 m / day or more and 30 m / day or less. The water supplied to the speed adjustment tank 42 is supplied to the biological purification tank 411 when its water level reaches or exceeds the position of the orifice hole h2 in the Z-axis direction, and is returned to the water storage tank 10 via the hose H2 when its water level reaches or exceeds the position of the overflow port P2 in the Z-axis direction.

[0099] (Step St34: Biological Filtration) The water supplied to the biological purification tank 411 is biologically filtered by the biological filtering material deposited in the biological purification tank 411. Purified water produced by the biological filtration of the water is supplied to the water storage tank 412 via the through-hole 41H.

[0100] (Step St35: Activated carbon filtration) When the water level of the purified water supplied to the water tank 412 reaches or exceeds the position in the Z-axis direction of the inlet 50a of the downcomer pipe 50, the purified water passes through the downcomer pipe 50 and the guide pipe 70 and is supplied to the activated carbon filtration tank 441. The activated carbon filtration tank 441 filters the purified water supplied from the water tank 412 using activated carbon.

[0101] (Step St36: Returning secondary purified water to the water storage tank) When the level of the secondary purified water generated by filtering the purified water through activated carbon reaches or exceeds the position of the drain outlet P4 in the Z-axis direction, the secondary purified water is returned to the water storage tank 10 via the hose H4. This keeps the level of the secondary purified water in the activated carbon filtration tank 441 at or below a predetermined level.

[0102] (Step St37: Sand Filtration) The secondary purified water produced by filtering the purified water through activated carbon is supplied to the sedimentation tank 4421. The secondary purified water supplied to the sedimentation tank 4421 is sand filtered by the sand filter material 442a deposited in the sedimentation tank 4421. The tertiary purified water produced by sand filtering the secondary purified water is supplied to the water storage tank 4422 via the through-hole 45H. When the water level of the tertiary purified water supplied to the water storage tank 4422 reaches or exceeds the position of the drain outlet P6 in the Z-axis direction, the tertiary purified water is supplied to the return pump 511.

[0103] (Step St38: Returning the tertiary purified water to the biological filtration tank) The return pump 511 sends the tertiary purified water to the T-joint t via the hose H5. The tertiary purified water branches at the T-joint t, and another portion of the tertiary purified water is returned to the biological purification tank 411 by the return pump 511. At this time, the speed of the tertiary purified water flowing into the biological purification tank 411 is controlled by the speed control valve V4 to, for example, between 5 m / day and 30 m / day.

[0104] (Step St39: UV Sterilization of Tertiary Purified Water) The return pump 511 sends the tertiary purified water to the T-joint t via the hose H5. The tertiary purified water branches at the T-joint t, and a portion of the tertiary purified water is supplied to the UV irradiation device 80. This portion is UV sterilized by being irradiated with UV light while flowing through the gap 82S, and becomes quaternary purified water.

[0105] (Step St40: Supplying Quaternary Purified Water to the Clean Water Tank) The quaternary purified water is supplied into the clean water tank 43 via the outlet 82H. When the water level of the quaternary purified water supplied to the clean water tank 43 reaches or exceeds the height of the guide pipe 70 in the Z-axis direction, the quaternary purified water passes through the guide pipe 70 and is returned to the activated carbon filtration tank 441.

[0106] 2. Supplementary Note: While the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0107] For example, the water purification device exemplified in the above embodiment is a device for purifying rainwater, but is not limited to this. The water purification device of the above embodiment may be a device for purifying water other than rainwater, such as seawater, river water, lake water, dam water, reservoir water, pool water, or groundwater, and the use of the present invention is not particularly limited.

[0108] Furthermore, the effects described in this specification are not limiting. In other words, the present invention may exhibit other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0109] The quality of rainwater stored in a water storage tank was tested before it was purified by the water purification device of the above embodiment. The results are shown in items 1 to 50 below and summarized in the table shown in Figure 17. Note that for the following test items, items for which water quality standards have been established are marked with an asterisk (*) to indicate non-compliance. The test method used was "the method established by the Minister of Health, Labour and Welfare based on the provisions of the Ministerial Ordinance on Water Quality Standards (Ministry of Health, Labour and Welfare Notification No. 261 of 2003)."

[0110] 1. Test item: Escherichia coli, Standard value: Not detected, Test result: Not detected 2. Test item: Cadmium and its compounds, Standard value: 0.003 mg / L or less, Test result: Less than 0.0003 mg / L 3. Test item: Mercury and its compounds, Standard value: 0.0005 mg / L or less, Test result: Less than 0.00005 mg / L 4. Test item: Selenium and its compounds, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L 5. Test item: Lead and its compounds, Standard value: 0.01 mg / L or less, Test result: 0.024 mg / L 6. Test item: Arsenic and its compounds, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L 7. 7. Test and inspection items: Hexavalent chromium compounds, Standard value: 0.02 mg / L or less, Test result: Less than 0.002 mg / L 8. Test and inspection items: Nitrite nitrogen, Standard value: 0.04 mg / L or less, Test result: Less than 0.004 mg / L 9. Test and inspection items: Cyanide ion and cyanogen chloride, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L 10. Test and inspection items: Nitrate nitrogen and nitrite nitrogen, Standard value: 10 mg / L or less, Test result: 0.27 mg / L 11. Test and inspection items: Fluorine and its compounds, Standard value: 0.8 mg / L or less, Test result: Less than 0.05 mg / L 12. Test and inspection items: Boron and its compounds, Standard value: 1.0 mg / L or less, Test result: Less than 0.05 mg / L 13. 13. Test and Inspection Item: Carbon Tetrachloride, Standard Value: 0.002 mg / L or Less, Test Result: Less than 0.0002 mg / L 14. Test and Inspection Item: 1,4-Dioxane, Standard Value: 0.05 mg / L or Less, Test Result: Less than 0.005 mg / L 15. Test and Inspection Item: cis-1,2-Dichloroethylene and trans-1,2-Dichloroethylene, Standard Value: 0.04 mg / L or Less, Test Result: Less than 0.0004 mg / L 16. Test and Inspection Item: Dichloromethane, Standard Value: 0.02 mg / L or Less, Test Result: Less than 0.001 mg / L 17. Test and Inspection Item: Tetrachloroethylene, Standard Value: 0.01 mg / L or Less, Test Result: Less than 0.001 mg / L 18. Test item: Trichloroethylene, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L19. Test item: Benzene, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L 20. Test item: Chloric acid, Standard value: 0.6 mg / L or less, Test result: Less than 0.06 mg / L 21. Test item: Chloroacetic acid, Standard value: 0.02 mg / L or less, Test result: Less than 0.002 mg / L 22. Test item: Chloroform, Standard value: 0.06 mg / L or less, Test result: Less than 0.001 mg / L 23. Test item: Dichloroacetic acid, Standard value: 0.03 mg / L or less, Test result: Less than 0.002 mg / L 24. Test item: Dibromochloromethane, Standard value: 0.1 mg / L or less, Test result: Less than 0.001 mg / L 25. 25. Test item: Bromate, Standard value: 0.01 mg / L or less, Test result: Less than 0.001 mg / L 26. Test item: Total trihalomethanes, Standard value: 0.1 mg / L or less, Test result: Less than 0.001 mg / L 27. Test item: Trichloroacetic acid, Standard value: 0.03 mg / L or less, Test result: Less than 0.002 mg / L 28. Test item: Bromodichloromethane, Standard value: 0.03 mg / L or less, Test result: Less than 0.001 mg / L 29. Test item: Bromoform, Standard value: 0.09 mg / L or less, Test result: Less than 0.001 mg / L 30. Test item: Formaldehyde, Standard value: 0.08 mg / L or less, Test result: Less than 0.008 mg / L 31. 31. Test item: Zinc and its compounds, Standard value: 1.0 mg / L or less, Test result: 0.017 mg / L 32. Test item: Aluminum and its compounds, Standard value: 0.2 mg / L or less, Test result: 0.03 mg / L 33. Test item: Iron and its compounds, Standard value: 0.3 mg / L or less, Test result: Less than 0.02 mg / L 34. Test item: Copper and its compounds, Standard value: 1.0 mg / L or less, Test result: Less than 0.005 mg / L 35. Test item: Sodium and its compounds, Standard value: 200 mg / L or less, Test result: 0.5 mg / L 36. Test item: Manganese and its compounds, Standard value: 0.05 mg / L or less, Test result: 0.008 mg / L 37. Test item: Chloride ion, Standard value: 200 mg / L or less, Test result: 1.9 mg / L38. Test items: calcium, magnesium, etc. (hardness), standard value: 300 CaCO ３ mg / L or less, test result: 2 CaCO ３ mg / L 39. Test item: Evaporation residue, Standard value: 500 mg / L or less, Test result: 21 mg / L 40. Test item: Anionic surfactant, Standard value: 0.2 mg / L or less, Test result: Less than 0.02 mg / L 41. Test item: Geosmin, Standard value: 0.00001 mg / L or less, Test result: Less than 0.000001 mg / L 42. Test item: 2-methylisoborneol, Standard value: 0.00001 mg / L or less, Test result: Less than 0.000001 mg / L 43. Test item: Nonionic surfactant, Standard value: 0.02 mg / L or less, Test result: 0.039 mg / L 44. Test item: Phenols, Standard value: 0.005 mg / L or less, Test result: Less than 0.0005 mg / L 45. 46. ​​Test item: Organic matter (total organic carbon (TOC) amount), standard value: 3 mg / L or less, test result: 2.2 mg / L 47. Test item: pH value, standard value: 5.8-8.6, test result: 5.6 (21°C) * 48. Test item: Odor, standard value: 3 mg / L, test result: 49. Test item: Color, standard value: 5 degrees or less, test result: 23 degrees * 50. Test item: Turbidity, standard value: 2 degrees or less, test result: 2.0 degrees

[0111] Using the water purification device of the above embodiment, water was circulated multiple times between the rainwater storage tank and the ecological purification device, as described in the above embodiment, and the quality of the purified water finally stored in the fresh water tank after circulation was tested. The results are shown in 51 to 77 below and summarized in the table shown in Figure 18. Note that for the following test items, items for which water quality standards have been established are marked with an asterisk (*) indicating non-compliance. The test method used was "the method prescribed by the Minister of Health, Labour and Welfare based on the provisions of the Ministerial Ordinance on Water Quality Standards (Ministry of Health, Labour and Welfare Notification No. 261 of 2003)."

[0112] 51. Test and Inspection Item: Escherichia coli, Standard Value: Not Detected, Test and Inspection Result: Not Detected 52. Test and Inspection Item: Lead and Its Compounds, Standard Value: 0.01 mg / L or Less, Test and Inspection Result: Less than 0.001 mg / L 53. Test and Inspection Item: Nitrite Nitrogen, Standard Value: 0.04 mg / L or Less, Test and Inspection Result: Less than 0.004 mg / L 54. Test and Inspection Item: Cyanide Ion and Cyanogen Chloride, Standard Value: 0.01 mg / L or Less, Test and Inspection Result: Less than 0.001 mg / L 55. Test and Inspection Item: Nitrate Nitrogen and Nitrite Nitrogen, Standard Value: 10 mg / L or Less, Test and Inspection Result: 0.04 mg / L 56. Test and Inspection Item: Chlorate, Standard Value: 0.6 mg / L or Less, Test and Inspection Result: Less than 0.06 mg / L 57. 57. Test item: Chloroacetic acid, standard value: 0.02 mg / L or less, test result: less than 0.002 mg / L 58. Test item: Chloroform, standard value: 0.06 mg / L or less, test result: less than 0.001 mg / L 59. Test item: Dichloroacetic acid, standard value: 0.03 mg / L or less, test result: less than 0.002 mg / L 60. Test item: Dibromochloromethane, standard value: 0.1 mg / L or less, test result: less than 0.001 mg / L 61. Test item: Bromic acid, standard value: 0.01 mg / L or less, test result: less than 0.001 mg / L 62. Test item: Total trihalomethanes, standard value: 0.1 mg / L or less, test result: less than 0.001 mg / L 63. 63. Test item: Trichloroacetic acid, Standard value: 0.03 mg / L or less, Test result: Less than 0.002 mg / L 64. Test item: Bromodichloromethane, Standard value: 0.03 mg / L or less, Test result: Less than 0.001 mg / L 65. Test item: Bromoform, Standard value: 0.09 mg / L or less, Test result: Less than 0.001 mg / L 66. Test item: Formaldehyde, Standard value: 0.08 mg / L or less, Test result: Less than 0.008 mg / L 67. Test item: Zinc and its compounds, Standard value: 1.0 mg / L or less, Test result: 0.33 mg / L 68. Test item: Iron and its compounds, Standard value: 0.3 mg / L or less, Test result: Less than 0.02 mg / L 69. Test item: Copper and its compounds, Standard value: 1.0 mg / L or less, Test result: Less than 0.005 mg / L70. Test item: Chloride ion, Standard value: 200 mg / L or less, Test result: 13 mg / L 71. Test item: Evaporation residue, Standard value: 500 mg / L or less, Test result: 55 mg / L 72. Test item: Organic matter (total organic carbon (TOC) amount), Standard value: 3 mg / L or less, Test result: 0.6 mg / L 73. Test item: pH value, Standard value: 5.8-8.6, Test result: 7.0 (17°C) 74. Test item: Taste, Standard value: No abnormalities, Test result: No abnormalities 75. Test item: Odor, Standard value: No abnormalities, Test result: No abnormalities 76. Test item: Color, Standard value: 5 degrees or less, Test result: 3.2 degrees 77. Test item: Turbidity, Standard value: 2 degrees or less, Test result: 0.2 degrees

[0113] Comparing the water quality test results shown in Figure 17 with those shown in Figure 18, it was found that the levels of "lead and its compounds," "nitrate nitrogen and nitrite nitrogen," and "organic matter" contained in the rainwater before purification were significantly reduced. In particular, "lead and its compounds" were significantly reduced, and the concentration of "lead and its compounds" contained in the purified water after purification was lower than the standard value. Furthermore, the pH value, odor, and color were also improved. As can be seen from the water quality test results shown in Figure 18, it was confirmed that the water stored in the fresh water tank after circulation was purified to a quality level suitable for drinking water, domestic use, etc. Therefore, it was found that according to the present invention, clean purified water can be obtained directly from rainwater without using a filter material such as a reverse osmosis membrane.

[0114] 10... Water storage tank 20... Liquid transfer pump 30, 310, 320... Renewable energy power source 40, 410, 510, 610... Biological purification device 41, 61... Biological filtration tank 42, 62... Speed ​​adjustment tank 43, 63... Clean water tank 44, 64... Secondary filtration tank 80... UV irradiation device 82... Supply pipe 83... UV lamp 100, 200, 300... Water purification device 411, 611... Biological purification tank 441, 641... Activated carbon filtration tank 442, 642... Sand filtration tank

Claims

1. A water purification device comprising: a water storage tank; a biological filtration tank for biologically filtering water; a speed adjustment tank for adjusting the speed of water supplied to the biological filtration tank; and a fresh water tank for storing water supplied from the biological filtration tank and returning the biologically filtered water to the water storage tank; and a liquid transfer pump for transferring water stored in the water storage tank to the speed adjustment tank, wherein water is circulated between the water storage tank and the biological purification device.

2. The water purification device according to claim 1, further comprising a renewable energy power source that supplies power to the liquid feed pump.

3. A water purification system comprising: a water storage tank; a biological filtration tank for biologically filtering water; a speed adjustment tank for adjusting the speed of water supplied to the biological filtration tank; a secondary filtration tank for secondarily filtering water supplied from the biological filtration tank; and a fresh water tank for storing water supplied from the secondary filtration tank and returning the secondarily filtered water to the water storage tank; and a liquid transfer pump for sending water stored in the water storage tank to the speed adjustment tank, wherein water is circulated between the water storage tank and the biological purification system.

4. The water purification device according to claim 3, further comprising a renewable energy power source that supplies power to the liquid feed pump.

5. A water purification device comprising: a water storage tank; a biological filtration tank for biologically filtering water; a speed adjustment tank for adjusting the speed of water supplied to the biological filtration tank; a secondary filtration tank for secondarily filtering water supplied from the biological filtration tank; a clear water tank for storing water supplied from the secondary filtration tank; and a return pump for returning the secondarily filtered water to the clear water tank and the biological filtration tank, wherein water is circulated between the biological filtration tank, the secondary filtration tank, and the clear water tank; and a liquid delivery pump for delivering water stored in the water storage tank to the speed adjustment tank.

6. The water purification device according to claim 5, further comprising a renewable energy power source that supplies power to the liquid delivery pump and the return pump.

7. The water purification device according to claim 4 or 6, wherein the secondary filtration tank comprises: an activated carbon filtration tank that uses activated carbon to filter the water supplied from the biological filtration tank; and a sand filtration tank that uses sand to filter the water that has been activated carbon filtered by the activated carbon filtration tank.

8. The water purification device according to claim 7, further comprising a UV irradiation device having a UV lamp and a supply pipe containing the UV lamp, wherein the UV lamp irradiates UV light onto the water that has been filtered through the activated carbon and sand in the secondary filtration tank.

9. The water purification device according to claim 8, wherein the renewable energy power source further supplies power to the UV lamp.

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