Water treatment system and purified water production method

Abstract

The present invention has a tank in which water to be treated is stored and a filtration device which is installed in the tank, wherein: the filtration device has a structure having in the interior thereof a plurality of filtration cells that generate treated water by filtering the water to be treated and a water collection hole that collects the treated water produced by the plurality of filtration cells; and there is further a first supply unit that is installed below the filtration device in the tank and that can supply air to each of the plurality of filtration cells.

Description

Water treatment system and purified water production method

[0001] The present invention relates to a water treatment system and a method for producing purified water.

[0002] For example, in water purification plants, water treatment systems (hereinafter simply referred to as water treatment systems) including a filtration device that produces purified water (hereinafter also referred to as treated water) by filtering raw water such as river water or well water (hereinafter also referred to as water to be treated) are used. Specifically, in such water treatment systems, for example, the water to be treated to which a coagulant has been added is stirred to cause suspended matter contained in the water to coagulate and settle, and then the water to be treated is filtered using a filtration device (see Patent Document 1).

[0003] JP 2014-188491 A

[0004] In the water treatment system described above, it is desirable to suppress a decrease in the filtration efficiency of the filtration device, for example.

[0005] The water treatment system of the present invention comprises a tank for storing water to be treated, and a filtration device installed within the tank, wherein the filtration device has a structure having therein a plurality of filtration cells that produce treated water by filtering the water to be treated, and a water collection hole that collects the treated water produced by the plurality of filtration cells, and further comprises a first supply unit installed below the filtration device within the tank and capable of supplying air to each of the plurality of filtration cells.

[0006] According to the water treatment system and purified water producing method of the present invention, it is possible to suppress a decrease in filtration efficiency.

[0007] FIG. 1 is a diagram illustrating a configuration example of a water treatment system 100 according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of a filtration device 10 according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of the filtration device 10 according to the first embodiment. FIG. 4 is a diagram illustrating a configuration example of the filtration device 10 according to the first embodiment. FIG. 5 is a diagram illustrating a configuration example of the filtration device 10 according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of the filtration device 10 according to the first embodiment. FIG. 7 is a diagram illustrating a configuration example of the filtration device 10 according to the first embodiment. FIG. 8 is a diagram illustrating a specific example of purified water generation control. FIG. 9 is a diagram illustrating a specific example of purified water generation control. FIG. 10 is a diagram illustrating a specific example of purified water generation control. FIG. 11 is a diagram illustrating the function of a control device 20. FIG. 12 is a diagram illustrating the hardware configuration of the control device 20. FIG. 13 is a flowchart illustrating purified water generation control according to the first embodiment. FIG. 14 is a flowchart illustrating purified water generation control according to the first embodiment. Fig. 15 is a flowchart illustrating purified water generation control in the first embodiment. Fig. 16 is a flowchart illustrating purified water generation control in the first embodiment. Fig. 17 is a flowchart illustrating purified water generation control in the first embodiment. Fig. 18 is a flowchart illustrating purified water generation control in the first embodiment. Fig. 19 is a diagram illustrating a configuration example of the filtration device 10 in a first modified example.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, such descriptions should not be interpreted in a limiting sense, and do not limit the subject matter described in the claims. Furthermore, various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure. Furthermore, different embodiments can be combined as appropriate.

[0009] [Water treatment system 100 according to a first embodiment] First, a configuration example of water treatment system 100 according to a first embodiment will be described. Fig. 1 is a diagram illustrating a configuration example of water treatment system 100 according to the first embodiment. Note that the arrangement positions and numbers of lines, pumps, valves, etc. shown below are merely examples and are not limited to these.

[0010] The water treatment system 100 includes, for example, a filtration device 10. The water treatment system 100 also includes, for example, a settling basin 11, a receiving well 12, and a mixing basin 13 as upstream equipment of the filtration device 10. The water treatment system 100 also includes, for example, a clear water basin 15 and a sludge basin 16.

[0011] The settling basin 11 is a tank into which the water to be treated W first flows via a line L11 that connects the settling basin 11 to a river or the like, and is a tank that settles and removes sediment and the like contained in the water to be treated W. The line L11 is, for example, a pipe that connects the settling basin 11 to a river or the like.

[0012] The receiving well 12 is, for example, a tank that adjusts the supply amount of the water W to be treated supplied from the settling basin 11 via the line L12 and supplies the water to the mixing basin 13. The line L12 is, for example, a pipe that connects the settling basin 11 and the receiving well 12.

[0013] The mixing basin 13 is a tank that, for example, injects a coagulant into the water W supplied from the receiving well 12 via line L13 and stirs the water W to coagulate suspended solids contained in the water W and form flocs. The line L13 is, for example, a pipe connecting the receiving well 12 and the mixing basin 13. The mixing basin 13 separates the formed flocs from the water W by, for example, settling them.

[0014] The filtration device 10 is used, for example, while submerged in the water to be treated W supplied from the mixing basin 13 via line L14, and produces treated water (purified water) by filtering the water to be treated W supplied from the mixing basin 13. The line L14 is, for example, a pipe connecting the mixing basin 13 with a storage tank 14 (hereinafter also simply referred to as tank 14) in which the water to be treated W supplied from the mixing basin 13 is stored.

[0015] Specifically, the filtration device 10 sequentially filters the water to be treated W stored in the storage tank 14 while being submerged in the water to be treated W stored in the storage tank 14 .

[0016] In addition to the water W to be treated supplied from the mixing basin 13, air A from the blower B1 is supplied to the storage tank 14 via a line L2.

[0017] Specifically, the air A from the blower B1 is blown out from the line L2, for example, and then rises through the water to be treated W stored in the storage tank 14, and is then supplied to the filtration device 10.

[0018] Furthermore, the filtration device 10 performs backwashing (cleaning) at regular intervals, such as every hour, by using a portion of the treated water filtered by the filtration device 10. Hereinafter, the timing at which the filtration device 10 filters the water W to be treated is also referred to as the filtration timing, and the timing at which the filtration device 10 performs backwashing is also referred to as the backwash timing.

[0019] In the above example, the water treatment system 100 has been described as having the mixing basin 13, but the present invention is not limited to this. Specifically, instead of the mixing basin 13, the water treatment system 100 may have, for example, a tank (not shown) for injecting a coagulant into the water to be treated W, a tank (not shown) for forming flocs by stirring the water to be treated W into which the coagulant has been injected, and a tank (not shown) for separating the formed flocs from the water to be treated W by precipitating them.

[0020] In the above example, the water treatment system 100 has been described as having one filtration device 10, but the present invention is not limited to this. Specifically, the water treatment system 100 may have, for example, multiple filtration devices 10 that perform distributed filtration of the water W to be treated supplied from the mixing basin 13. Each of the multiple filtration devices 10 may perform backwashing at different time periods, for example.

[0021] The purified water reservoir 15 is, for example, a tank that stores treated water supplied from the filtration device 10 via a line L1. The line L1 is, for example, a pipe that connects the filtration device 10 and the purified water reservoir 15.

[0022] Specifically, the suction pump P1 (hereinafter simply referred to as pump P1) provided on the line L1, for example, sucks up the treated water after filtration in the filtration device 10, thereby supplying the treated water produced in the filtration device 10 to the purified water reservoir 15 via the line L1.

[0023] For example, if there is a water level difference between the purified water reservoir 15 and the filtration device 10 (hereinafter simply referred to as the water level difference), the filtration device 10 may filter the water to be treated by utilizing the water level difference. Specifically, in this case, the filtration device 10 may filter the water to be treated by utilizing the water level difference instead of suction by the suction pump P1. Furthermore, the filtration device 10 may filter the water to be treated by utilizing the water level difference in addition to suction by the suction pump P1.

[0024] This allows the filtration device 10 to filter the water to be treated without requiring any power source. Also, the filtration device 10 allows the water to be filtered while suppressing the power consumption of the suction pump P1.

[0025] The water treatment system 100 may further include, for example, another storage tank (not shown) for storing treated water sucked from the filtration device 10 by the suction pump P1, and another supply pump (not shown) for supplying the treated water stored in the other storage tank to the purified water reservoir 15.

[0026] The treated water stored in the purified water reservoir 15 is then supplied to a distributing reservoir (not shown) via, for example, a line L4. The line L4 is, for example, a pipe connecting the purified water reservoir 15 and the distributing reservoir.

[0027] In addition, a portion of the treated water stored in the purified water reservoir 15 is used, for example, as backwash water for backwashing the filtration device 10 .

[0028] Specifically, the supply pump P2 (hereinafter simply referred to as pump P2) provided on the line L5 supplies a portion of the treated water stored in the purified water reservoir 15 to the filtration device 10 via the line L5 and a portion of the line L1, for example, during backwashing. The line L5 is, for example, a pipe connecting the purified water reservoir 15 and the line L1.

[0029] The water treatment system 100 may further include a backwash water storage tank (not shown) for storing treated water (a portion of the treated water stored in the purified water reservoir 15) to be used as backwash water. The supply pump P2 may supply the treated water stored in the storage tank to the filtration device 10.

[0030] The waste sludge basin 16 is, for example, a tank that stores solid matter S (hereinafter also referred to as sludge S) discharged from the filtration device 10 via line L3. The line L3 is, for example, a pipe that connects the filtration device 10 (the bottom of the storage tank 14) and the waste sludge basin 16.

[0031] Specifically, the suction pump P3 (hereinafter simply referred to as pump P3) provided on the line L3 sucks up solids S (solids S deposited at the bottom of the storage tank 14) discharged from the filtration device 10 during the filtration of the treated water W, and thereby discharges the solids S from the storage tank 14 to the waste sludge tank 16 via the line L3.

[0032] The solids S supplied to the waste sludge basin 16 are then supplied to downstream equipment (not shown), such as wastewater treatment equipment, via a line L6. The line L6 is, for example, a pipe connecting the waste sludge basin 16 with downstream equipment.

[0033] Hereinafter, blower B1 and line L2 will be collectively referred to as first supply unit 21. Hereinafter, suction pump P1, line L1, line L5, valve V1, and valve V2 will be collectively referred to as second supply unit 22. Furthermore, suction pump P3 and line L3 will be collectively referred to as discharge unit 23.

[0034] Filtration Device 10 in First Embodiment Figures 2 to 7 are diagrams illustrating an example of the configuration of the filtration device 10 in the first embodiment. Specifically, Figure 2 is a perspective view of the filtration device 10. Figure 3 is a front view of the filtration device 10. Figure 4 is a top view of the filtration device 10. Figure 5 is a side view of the filtration device 10. Figure 6 is a perspective view of the element 1. Figure 7 is a top view of the element 1.

[0035] As shown in Figures 2 to 5, the filtration device 10 has, for example, a plurality of elements 1 (hereinafter also referred to as a plurality of structures 1) that filter the water to be treated W, a supply pipe 2 that supplies the treated water after filtering by the plurality of elements 1 to other equipment, and a housing 3 that houses the plurality of elements 1 inside.

[0036] As shown in FIG. 6, the element 1 is, for example, a cylindrical columnar structure, and is a porous body having an end face 1a (hereinafter also referred to as a first end face 1a), an end face 1b (hereinafter also referred to as a second end face 1b) located opposite the end face 1a, and a side face 1c connecting the end face 1a and the end face 1b.

[0037] As shown in Figure 7, the element 1 has, for example, a plurality of filtration cells 1d that produce treated water by filtering the water to be treated W stored in the storage tank 14, and a water collection hole 1e inside that collects the treated water produced by the plurality of filtration cells 1d.

[0038] The water collection hole 1e is, for example, a bottomed recess that is open on the end face 1a side and closed on the end face 1b side. The water collection hole 1e is provided, for example, at the center of the cross section of the element 1 in the longitudinal direction.

[0039] Each of the plurality of filtration cells 1d is, for example, a hole extending in the longitudinal direction of the element 1 and penetrating from the end face 1a to the end face 1b. Each of the plurality of filtration cells 1d is provided, for example, around the water collection hole 1e in the cross section of the element 1 in the longitudinal direction.

[0040] Specifically, when filtering the water W to be treated, the water W flows into each filtration cell 1d, for example, from the end face 1a side and the end face 1b side. The water W that has flowed into each filtration cell 1d is filtered (solid-liquid separation) as it passes through, for example, a filtration membrane (hereinafter simply referred to as a membrane) that forms the inner wall of each filtration cell 1d. The filtered treated water is then collected, for example, in a water collection hole 1e. Meanwhile, solids S separated by filtration remain, for example, in each filtration cell 1d.

[0041] The element 1 may further include, for example, a plurality of water collection cells (not shown) that temporarily collect the treated water produced by the plurality of filtration cells 1 d, and a plurality of slits (not shown) that supply the treated water collected by each of the plurality of water collection cells to the water collection hole 1 e. Each of the plurality of water collection cells is, for example, a hole provided inside the element 1 (around each of the filtration cells 1 d in the longitudinal cross section of the element 1) and extending in the longitudinal direction of the element 1. Furthermore, each of the plurality of slits is, for example, a slit provided inside the element 1 that connects the plurality of water collection cells to the water collection hole 1 e.

[0042] In this case, the treated water that has permeated the membrane of each filtration cell 1d may be collected in each collection cell, and the treated water collected in each collection cell may be collected in the collection hole 1e through each slit.

[0043] Returning to FIG. 2 to FIG. 5, the housing 3 has, for example, a housing main body 3a, a plurality of openings 3b, a plurality of openings 3c, and a connecting portion 3d.

[0044] The housing body 3 a accommodates, for example, a plurality of elements 1. Specifically, the housing body 3 a accommodates, for example, each element 1 in a state where the longitudinal direction of each element 1 (each of the plurality of filtration cells 1 d and the water collection holes 1 e included in each element 1) is arranged along the Z-axis direction.

[0045] In the following, a case will be described in which ten elements 1 are arranged along the X-axis direction and two elements 1 are arranged in the Y-axis direction within the housing main body 3a. That is, a case in which 20 elements 1 are housed in the housing main body 3a will be described below.

[0046] Each of the plurality of openings 3b is provided, for example, on the Z1 direction side (above) of the housing position of each element 1 in the housing body 3a, and opens toward the Z1 direction.

[0047] Each of the plurality of openings 3c is provided, for example, on the Z2 direction side (below) of the housing position of each element 1 in the housing body 3a, and opens toward the Z2 direction.

[0048] Specifically, when filtering the water W to be treated, the water W to be treated flows into the housing body 3a through, for example, each of the openings 3b and each of the openings 3c.

[0049] The connecting portion 3d is provided, for example, on the Z1 side (above) of the housing position of the housing body 3a where the element 1 is housed, and connects the housing body 3a to the supply pipe 2 located on the Z1 side of the housing body 3a.

[0050] For example, when the water to be treated W is filtered, the supply pipe 2 supplies the treated water filtered in the element 1 to the line L1, and when the filtration device 10 (element 1) is backwashed, the supply pipe 2 supplies the treated water (backwash water) used for backwashing to the element 1. Specifically, the supply pipe 2 has, for example, a pipe main body 2a and a plurality of branch pipes 2b.

[0051] The pipe main body 2a extends, for example, along the X-axis direction, with one end on the X2 direction side communicating with the line L1 and one end on the X1 direction side being closed.

[0052] Each of the branch pipes 2b has, for example, one end on the Z2 side communicating with the water collection hole 1e of each element 1 and one end on the Z1 side communicating with the pipe main body 2a. Each branch pipe 2b supplies, for example, treated water collected in the water collection hole 1e of each element 1 to the pipe main body 2a.

[0053] Specifically, the suction pump P1, for example, sucks the treated water collected in the water collection hole 1e of each element 1 through each branch pipe 2b, the pipe body 2a and the line L1, thereby supplying the treated water after filtration in the filtration device 10 to the purified water reservoir 15.

[0054] Here, the supply pipe 2 (pipe body 2a) is provided, for example, on the Z1 direction side (above) of each element 1 (water collection hole 1e of each element 1).

[0055] This allows the suction pump P1 to easily suck, for example, treated water from each element 1 (treated water collected in the water collection hole 1 e of each element 1). In other words, the suction pump P1 can reduce the load required to suck treated water from each element 1 and the costs, such as power consumption, etc.

[0056] [Specific example of purified water generation control] Next, a specific example of control for generating treated water from water to be treated W in the filtration device 10 (hereinafter also referred to as purified water generation control) will be described. Figures 8 to 10 are diagrams for explaining a specific example of purified water generation control. Specifically, Figures 8 to 10 are schematic diagrams showing the element 1 submerged in the water to be treated W stored in the storage tank 14. Furthermore, the solid arrows in Figure 8 indicate the flow of the water to be treated W. Furthermore, the solid arrows in Figure 9 indicate the flow of air A. Furthermore, the solid arrows in Figure 10 indicate the flow of backwash water.

[0057] First, a specific example of the purified water generation control (hereinafter also referred to as first control) for filtering the water to be treated W will be described. Figures 8 and 9 are diagrams for explaining a specific example of the first control.

[0058] The treated water W that flows into the housing body 3a from each of the openings 3b (Z1 direction side) and 3c (Z2 direction side) flows into each filtration cell 1d, for example, from each of the end face 1a side (Z1 direction side) and end face 1b side (Z2 direction side), as shown in Figure 8.

[0059] The water W to be treated that has flowed into each filtration cell 1 d then flows into the water collection hole 1 e, for example, by passing through the membrane of each filtration cell 1 d. That is, the membrane of each filtration cell 1 d filters the water W to be treated while the water W flows from each filtration cell 1 d into the water collection hole 1 e.

[0060] Thereafter, the treated water (treated water after being filtered) that has flowed into the water collection hole 1e is sucked through the branch pipe 2b by, for example, a suction pump P1.

[0061] That is, the suction pump P1 sucks the water to be treated W stored in the storage tank 14, for example, through the inside of the housing main body 3a, the filtration cell 1d, the water collection hole 1e, the branch pipe 2b, the pipe main body 2a, and the line L1.

[0062] This allows the filtration device 10 in this embodiment to filter, for example, the water to be treated W stored in the storage tank 14. The filtration device 10 can then supply the filtered treated water to downstream equipment (clean water reservoir 15), for example.

[0063] Furthermore, as shown in FIG. 9, each filtration cell 1d is further supplied with air A supplied from a blower B1 via a line L2, for example.

[0064] Specifically, for example, air A is intermittently supplied to each filtration cell 1d during execution of the first control. Then, the air A supplied from the blower B1 is, for example, ejected from a line L2 in the storage tank 14, and then rises within the water to be treated W stored in the storage tank 14. After that, the air A rises to the height of the end face 1b of each element 1, and flows into, for example, each filtration cell 1d.

[0065] That is, for example, when the water W to be treated flowing from the storage tank 14 is filtered in each filtration cell 1d, solids S separated from the water W to be treated remain in the form of adhering to the membrane of each filtration cell 1d. Therefore, in the filtration device 10, for example, by backwashing the filtration device 10, the solids S in each filtration cell 1d are peeled off from the membrane of each filtration cell 1d and discharged from each filtration cell 1d.

[0066] However, for example, when the interval between backwashing of the filtration device 10 is long, i.e., when the backwashing of the filtration device 10 is performed infrequently, the solids S may penetrate not only the surface of the membrane of each filtration cell 1d but also inside the membrane of each filtration cell 1d, making it difficult to sufficiently peel off and discharge the solids S by backwashing. Furthermore, in a situation where the solids S have penetrated inside the membrane of each filtration cell 1d, in order to sufficiently peel off and discharge the solids S, it may be necessary to perform backwashing using, for example, a huge amount of backwash water in the filtration device 10.

[0067] Therefore, in the filtration device 10 of this embodiment, for example, even when filtering the water to be treated W (when the first control is being performed), air A is supplied into each filtration cell 1 d to prevent solids S from adhering to the surface of the membrane in each filtration cell 1 d. In other words, the control device 20 prevents solids S from entering inside the membrane of each filtration cell 1 d by suppressing adhesion of solids S to the surface of the membrane in each filtration cell 1 d, for example, even when filtering the water to be treated W. Then, the control device 20 discharges the peeled solids S from the end face 1 a side (Z1 direction side) to the outside of each filtration cell 1 d by, for example, using an upward flow of air A in each filtration cell 1 d.

[0068] As a result, the filtration device 10 in this embodiment can sufficiently perform peeling and discharge of the solids S by backwashing the filtration device 10 without increasing the amount of backwash water, for example. Therefore, the filtration device 10 can suppress a decrease in the filtration efficiency of the water to be treated W without increasing the amount of backwash water, for example.

[0069] Next, a specific example of the purified water production control (hereinafter also referred to as second control) for backwashing the filtration device 10 will be described. Fig. 10 is a diagram for explaining a specific example of the second control.

[0070] The backwash water supplied from the clear water reservoir 15 via the line L5 and a part of the line L1 flows into the water collection hole 1e via the branch pipe 2b, for example, as shown in FIG.

[0071] The treated water that has flowed into the water collection hole 1e then flows into each filtration cell 1d by passing through the membrane, thereby peeling off solid matter S that has adhered to the membrane.

[0072] Thereafter, the backwash water that has flowed into each filtration cell 1d flows out into the housing body 3a, for example, from the end face 1a side (Z1 direction side) and the end face 1b side (Z2 direction side). That is, the backwash water flowing out from each filtration cell 1d into the housing body 3a discharges, for example, exfoliated solids S from each filtration cell 1d. Specifically, the backwash water flowing out from each filtration cell 1d into the housing body 3a discharges, for example, not only the solids S exfoliated in the second control but also the solids S exfoliated in the first control (solids S that were not discharged by the upward flow of air A) from each filtration cell 1d.

[0073] The backwash water flowing into the housing body 3a flows into the storage tank 14, for example, from the opening 3b (Z1 direction side) and the opening 3c (Z2 direction side). That is, the backwash water flowing from the housing body 3a into the storage tank 14 discharges, for example, the solids S discharged from each filtration cell 1d into the storage tank 14.

[0074] Thus, the water treatment system 100 in this embodiment includes, for example, a storage tank 14 that stores the water to be treated W, and a filtration device 10 installed in the storage tank 14. The filtration device 10 in this embodiment includes an element 1 that includes a plurality of filtration cells 1d that generate treated water by filtering the water to be treated W, and a water collection hole 1e that collects the treated water generated by the plurality of filtration cells 1d. The water treatment system 100 also includes, for example, a first supply unit 21 that is installed below the filtration device 10 in the storage tank 14 and is capable of supplying air to each of the plurality of filtration cells 1d.

[0075] Specifically, the element 1 is installed so that the water collecting holes 1e and the plurality of filtration cells 1d extend in the vertical direction, for example.

[0076] The water treatment system 100 also includes a second supply unit 22 that is installed, for example, above the filtration device 10 in the storage tank 14 and that can supply treated water collected by the water collection hole 1 e to other devices. Furthermore, the second supply unit 22 supplies backwash water to the water collection hole 1 e, for example, to be used for backwashing the multiple filtration cells 1 d.

[0077] The water treatment system 100 also has a discharge section 23 that is installed, for example, below the filtration device 10 in the storage tank 14 and is capable of discharging solids S that are discharged from the multiple filtration cells 1d as a result of backwashing the multiple filtration cells 1d and that have settled at the bottom of the storage tank 14 to another device.

[0078] That is, in the water treatment system 100 of this embodiment, for example, the solids S adhering to the membrane in each filtration cell 1d are peeled off and discharged by supplying air A into each filtration cell 1d, even during filtration of the water to be treated W. In other words, in the water treatment system 100, for example, the solids S adhering to the membrane in each filtration cell 1d are peeled off and discharged not only during backwashing of the filtration device 10, but also during filtration of the water to be treated W.

[0079] As a result, the filtration device 10 in this embodiment can sufficiently perform peeling and discharge of the solids S by backwashing the filtration device 10 without increasing the amount of backwash water, for example. Therefore, the filtration device 10 can suppress a decrease in the filtration efficiency of the water to be treated W without increasing the amount of backwash water, for example.

[0080] [Control device 20 in first embodiment] Fig. 11 is a diagram illustrating the functions of the control device 20. Fig. 12 is a diagram illustrating the hardware configuration of the control device 20.

[0081] As shown in FIG. 11, the water treatment system 100 has a control device 20 that performs purified water production control by controlling, for example, a suction pump P1, a supply pump P2, a suction pump P3, a blower B1, a valve V1 provided in line L1, and a valve V2 provided in line L5.

[0082] Specifically, when performing the first control, the control device 20 controls to open the valve V1 and activates the suction pump P1, thereby sucking treated water from the filtration device 10 via the line L1 and supplying it to the purified water reservoir 15. In this case, the control device 20 also activates the blower B1, for example, to supply air A to the filtration device 10 (each filtration cell 1d) via the line L2.

[0083] On the other hand, when the control device 20 performs the second control, for example, by controlling the valve V2 to open and starting the supply pump P2, backwash water is supplied from the purified water reservoir 15 to the filtration device 10 via line L5 and a part of line L1.

[0084] 12, the control device 20 is, for example, an electronic device having an electronic circuit. Specifically, the control device 20 is, for example, a computer device having a CPU 201 which is a processor, a memory 202, a communication device 203, and a storage medium 204. Each unit is connected to each other via, for example, a bus 205.

[0085] The storage medium 204 has, for example, a program storage area (not shown) for storing a program 210 for performing purified water generation control. The storage medium 204 also has, for example, an information storage area 230 for storing information used when performing purified water generation control. The storage medium 204 may be, for example, a hard disk drive (HDD) or a solid state drive (SSD).

[0086] The CPU 201 controls purified water production by executing a program 210 loaded from the storage medium 204 to the memory 202, for example.

[0087] The communication device 203 accesses an operation terminal (not shown) through which an operator inputs necessary information, for example, via a network (not shown) such as the Internet.

[0088] The control device 20 may include, for example, a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). The control device 20 may also include, for example, a peripheral interface controller (PIC). The purified water generation control may be performed by, for example, the FPGA or the ASIC.

[0089] [Details of Purified Water Generation Control] Next, details of purified water generation control in the first embodiment will be described. Figures 13 to 18 are flow charts illustrating purified water generation control in the first embodiment.

[0090] [Details of First Control] First, the details of the first control will be described. Fig. 13 is a flowchart illustrating the first control. Note that the following description will be given assuming that, as an initial state, the pumps P1, P2, P3, and the blower B1 are stopped, and the valves V1 and V2 are closed.

[0091] The control device 20 starts, for example, filtering of the water to be treated W stored in the storage tank 14 (step S1 in FIG. 13).

[0092] Specifically, the control device 20 starts filtering the water to be treated W stored in the storage tank 14, for example, by starting the pump P1 and opening the valve V1.

[0093] Then, for example, when a first condition is satisfied, the control device 20 starts supplying (hereinafter also referred to as bubbling) air A to the element 1 (each filtration cell 1d) while continuing to filter the water W to be treated stored in the storage tank 14 (steps S2 and S3 in FIG. 13). The first condition is, for example, that the elapsed time since step S1 was performed reaches a first time (for example, several minutes).

[0094] Specifically, the control device 20 starts the supply of air A to the storage tank 14 (element 1), for example, by starting the blower B1.

[0095] Thereafter, when, for example, a second condition is satisfied, the control device 20 stops the supply of air A to the element 1 while continuing to filter the water W stored in the storage tank 14 (steps S4 and S5 in FIG. 13 ). The second condition is, for example, that the elapsed time since step S3 has been performed has reached a second time (for example, several seconds).

[0096] Specifically, the control device 20 stops the supply of air A to the storage tank 14 (element 1), for example, by stopping the blower B1.

[0097] The control device 20 may, for example, repeatedly perform steps S2 to S5 while filtering is being performed on the water W to be treated stored in the storage tank 14. In this case, the first condition may, for example, be that the elapsed time since the previous step S5 was performed has reached a first time.

[0098] Furthermore, the control device 20 may, for example, constantly supply air A to the storage tank 14 (element 1) while the water to be treated W stored in the storage tank 14 is being filtered.

[0099] [Details of Second Control] Next, the details of the second control will be described with reference to Fig. 14, which is a flowchart illustrating the second control.

[0100] The control device 20 starts filtering the water to be treated W stored in the storage tank 14 (step S11 in FIG. 14), for example, in the same manner as in step S1 in FIG. 13.

[0101] Specifically, the control device 20 starts filtering the water to be treated W stored in the storage tank 14, for example, by starting the pump P1 and opening the valve V1.

[0102] Then, for example, when a third condition is satisfied, the control device 20 stops filtering the water W stored in the storage tank 14 (steps S12 and S13 in FIG. 14 ). The third condition is, for example, that the elapsed time since step S11 has been performed has reached a third time (e.g., several hours).

[0103] Specifically, the control device 20 stops the filtration of the water to be treated W stored in the storage tank 14, for example, by performing control to stop the pump P1 and close the valve V1.

[0104] Next, the control device 20 starts, for example, backwashing of the filtration device 10 (step S14 in FIG. 14).

[0105] Specifically, the control device 20 starts backwashing of the filtration device 10 by, for example, starting the pump P2 and opening the valve V2.

[0106] Thereafter, the control device 20 terminates the backwashing of the filtration device 10 when, for example, a fourth condition is satisfied (steps S15 and S16 in FIG. 14 ). The fourth condition is, for example, that the elapsed time since step S14 has been performed reaches a fourth time (for example, several tens of minutes).

[0107] Specifically, the control device 20 stops the pump P2 and closes the valve V2, for example, thereby ending the backwashing of the filtration device 10.

[0108] Then, the control device 20 resumes, for example, filtering of the water to be treated W stored in the storage tank 14 (step S17 in FIG. 14).

[0109] Specifically, the control device 20 restarts the filtration of the water to be treated W stored in the storage tank 14, for example, by starting the pump P1 and opening the valve V1.

[0110] The control device 20 may, for example, repeatedly perform steps S12 to S17 while filtering is being performed on the water W to be treated stored in the storage tank 14. In this case, the third condition may, for example, be that the elapsed time since the previous step S17 was performed reaches a third hour.

[0111] [Details of Third Control] Next, the control (hereinafter also referred to as third control) for the time period during which air A is continuously supplied in the first control (i.e., the second time period) will be described. Fig. 15 is a flowchart illustrating the third control.

[0112] The control device 20 acquires, for example, from a measuring device (not shown) installed in the storage tank 14, measurement values ​​for at least one of the water quality of the treated water W stored in the storage tank 14 and the differential pressure in the filtration device 10 (step S21 in Figure 15).

[0113] Specifically, the measuring device may be, for example, a measuring device that measures the turbidity concentration in the water to be treated W. In this case, the control device 20 may be, for example, a device that acquires the turbidity concentration in the water to be treated W stored in the storage tank 14.

[0114] The measuring device may be, for example, a measuring device that measures the concentration of suspended solids (SS) in the water to be treated W. In this case, the control device 20 may be, for example, a device that acquires the concentration of suspended solids in the water to be treated W stored in the storage tank 14.

[0115] Furthermore, the measuring device may be, for example, a measuring device that measures the differential pressure in the filtration device 10. Specifically, the measuring device may be, for example, a device that measures the pressure of the water W to be treated in the storage tank 14 (e.g., the pressure of the water W to be treated that has flowed between the housing main body 3a and the element 1) and the pressure of the water W to be treated in the branch pipe 2b, and calculates the difference between these pressures to calculate the differential pressure in the filtration device 10. In this case, the control device 20 may be, for example, a device that acquires the differential pressure in the filtration device 10.

[0116] Next, when, for example, a fifth condition is satisfied, the control device 20 controls the time (second time) for supplying air A in step S3, etc. (steps S22 and S23 in FIG. 15 ). The fifth condition is, for example, that the measurement value acquired in step S21 is outside a predetermined range.

[0117] Specifically, for example, if the measurement value obtained in step S21 exceeds a predetermined upper limit threshold (hereinafter simply referred to as the upper limit threshold), the control device 20 performs control to extend the time for which air A is supplied in step S3, etc.

[0118] As a result, the control device 20 in this embodiment can, for example, sufficiently prevent solid matter S from adhering within each filtration cell 1d, thereby preventing a decrease in filtration efficiency.

[0119] On the other hand, for example, if the measurement value obtained in step S21 is below a predetermined lower threshold value (hereinafter simply referred to as the lower threshold value), the control device 20 performs control to shorten the time for supplying air A in step S3, etc.

[0120] As a result, the control device 20 in this embodiment can reduce the load on the blower B1 required to supply the air A, the power consumption, and other costs, for example.

[0121] [Details of Fourth Control] Next, the control of the supply interval of air A (i.e., the first time) in the first control (hereinafter also referred to as the fourth control) will be described. Fig. 16 is a flowchart illustrating the fourth control.

[0122] The control device 20 acquires measurement values ​​for at least one of the water quality of the treated water W stored in the storage tank 14 and the differential pressure in the filtration device 10 from a measuring device installed in the storage tank 14, as in step S21 of Figure 15 (step S31 of Figure 16).

[0123] Next, when the fifth condition is satisfied, for example, the control device 20 controls the interval (first time) at which air A is supplied in step S3 or the like (steps S32 and S33 in FIG. 16).

[0124] Specifically, for example, if the measurement value acquired in step S31 exceeds the upper threshold, the control device 20 performs control to shorten the supply interval of air A (supply cycle of air A) in step S3, etc.

[0125] As a result, the control device 20 in this embodiment can sufficiently prevent solid matter S from adhering within each filtration cell 1d, as in the third control, for example, and can prevent a decrease in filtration efficiency.

[0126] On the other hand, for example, if the measurement value acquired in step S31 is below the lower threshold, the control device 20 performs control to lengthen the interval at which air A is supplied in step S3 or the like.

[0127] As a result, the control device 20 in this embodiment can reduce the load on the blower B1 required to supply air A, power consumption, and other costs, as in the case of the third control, for example.

[0128] Note that the control device 20 may perform, for example, the third control and the fourth control in parallel. Specifically, for example, when the measurement value acquired in step S21 (step S31) exceeds the upper threshold, the control device 20 may perform control in step S3, etc. to lengthen the time for which air A is supplied and control to shorten the interval between supplies of air A. Also, for example, when the measurement value acquired in step S21 (step S31) is below the lower threshold, the control device 20 may perform control in step S3, etc. to shorten the time for which air A is supplied and control to lengthen the interval between supplies of air A.

[0129] [Details of Fifth Control] Next, the control (hereinafter also referred to as fifth control) for the time during which the backwashing of the filtration device 10 is performed in the second control (i.e., the fourth time) will be described. Fig. 17 is a flowchart illustrating the fifth control.

[0130] The control device 20 acquires measurement values ​​for at least one of the water quality of the treated water W stored in the storage tank 14 and the differential pressure in the filtration device 10 from a measuring device installed in the storage tank 14, as in step S21 of Figure 15 (step S41 of Figure 17).

[0131] Next, when the fifth condition is satisfied, for example, the control device 20 controls the time (fourth time) for backwashing the filtration device 10 in step S14 or the like (steps S42 and S43 in FIG. 17 ). That is, in this case, the control device 20 controls the time for supplying backwash water in step S14 or the like.

[0132] Specifically, for example, when the measurement value acquired in step S41 exceeds the upper threshold, the control device 20 performs control to lengthen the time for backwashing the filtration device 10 in step S14 or the like.

[0133] As a result, the control device 20 in this embodiment can, for example, sufficiently prevent solid matter S from adhering within each filtration cell 1d, thereby preventing a decrease in filtration efficiency.

[0134] On the other hand, for example, if the measurement value acquired in step S41 is below the lower threshold, the control device 20 performs control to shorten the time for backwashing the filtration device 10 in step S14 or the like.

[0135] As a result, the control device 20 in this embodiment can reduce costs such as the load on the pump P2 required to supply backwash water to the filtration device 10 and power consumption.

[0136] [Details of Sixth Control] Next, the control (hereinafter also referred to as sixth control) for the interval (i.e., the third time) at which the backwashing of the filtration device 10 is performed in the second control will be described. Fig. 18 is a flowchart illustrating the sixth control.

[0137] The control device 20 acquires measurement values ​​for at least one of the water quality of the treated water W stored in the storage tank 14 and the differential pressure in the filtration device 10 from a measuring device installed in the storage tank 14, as in step S21 of Figure 15, for example (step S51 of Figure 18).

[0138] Next, for example, when the fifth condition is satisfied, the control device 20 controls the interval (third time) for backwashing the filtration device 10 in step S14 or the like (steps S52 and S53 in FIG. 18 ). That is, in this case, the control device 20 controls the interval for supplying backwash water in step S14 or the like.

[0139] Specifically, for example, when the measurement value acquired in step S51 exceeds the upper threshold, the control device 20 performs control to shorten the interval between backwashing of the filtration device 10 in step S14 or the like.

[0140] As a result, the control device 20 in this embodiment can sufficiently prevent solid matter S from adhering within each filtration cell 1d, as in the case of the fifth control, for example, and can prevent a decrease in filtration efficiency.

[0141] On the other hand, for example, if the measurement value acquired in step S51 is below the lower threshold, the control device 20 performs control to lengthen the interval between backwashing of the filtration device 10 in step S14 or the like.

[0142] As a result, the control device 20 in this embodiment can reduce costs such as the load on the pump P2 required to supply backwash water and power consumption, as in the case of the fifth control, for example.

[0143] The control device 20 may perform the fifth control and the sixth control in parallel, for example. Specifically, for example, when the measurement value acquired in step S41 (step S51) is above an upper threshold, the control device 20 may perform control to lengthen the time for backwashing the filtration device 10 and control to shorten the interval between backwashing the filtration device 10 in step S14, etc. Furthermore, for example, when the measurement value acquired in step S41 (step S51) is below a lower threshold, the control device 20 may perform control to shorten the time for backwashing the filtration device 10 and control to lengthen the interval between backwashing the filtration device 10 in step S14, etc.

[0144] Thus, the water treatment system 100 in this embodiment has, for example, a control device 20 that controls the supply of air A by the first supply unit 21. The control device 20 acquires, for example, a measurement value for at least one of the water quality of the water to be treated W and the differential pressure in the filtration device 10, and controls the supply of air A by the first supply unit 21 in accordance with the acquired measurement value.

[0145] As a result, the water treatment system 100 in this embodiment can, for example, reduce the cost required for filtering the water to be treated W while preventing solid matter S from adhering within each filtration cell 1d and preventing a decrease in filtration efficiency.

[0146] [Filtration Device 10 in First Modification] Next, a configuration example of the filtration device 10 in a modification of the first embodiment (hereinafter also referred to as the first modification) will be described. Fig. 19 is a diagram illustrating the configuration example of the filtration device 10 in the first modification.

[0147] As shown in FIG. 19, the housing 3 in this modification further includes, for example, a plurality of skirt portions 3e.

[0148] Each of the skirt portions 3e has, for example, a cylindrical shape extending in the Z-axis direction and is attached to the Z2-direction end of the housing body 3a on the Z2-direction side (downward) of the storage position of each element 1. Each skirt portion 3e is attached to, for example, the Z2-direction end of the housing body 3a, thereby forming a recess that opens toward the Z2-direction side (downward) together with the Z2-direction end of the housing body 3a. Note that each skirt portion 3e may have a shape other than a cylindrical shape, such as a hollow rectangular shape extending in the Z-axis direction.

[0149] Specifically, each skirt portion 3 e accommodates (captures) therein air A that has risen to approximately the height of the end surface 1 b (air A that has risen to approximately the height of the end surface 1 b in the water to be treated W stored in the storage tank 14). Then, the air A accommodated in each skirt portion 3 e sequentially flows into, for example, each filtration cell 1 d.

[0150] As described above, the filtration device 10 in this modification has, for example, a skirt portion 3e located below the filtration cell 1d and collecting the air A supplied from the first supply unit 21. The air A collected in the skirt portion 3e then flows into, for example, the filtration cell 1d.

[0151] That is, for example, if the skirt portions 3e are not attached to the housing 3, part of the air A that has risen to near the height of the end face 1b will continue to rise within the water to be treated W without flowing into the filtration cells 1d. Therefore, in this case, the filtration device 10 will not be able to efficiently allow the air A ejected from the line L2 to flow into the filtration cells 1d.

[0152] In contrast, the filtering device 10 of this modified example can temporarily hold the air A that has risen to near the height of the end face 1b at a position lower than the end face 1b (a position at which the air can flow into each filtering cell 1d) by attaching each skirt portion 3e to the housing 3. Therefore, the filtering device 10 can sequentially cause the air A that has risen to near the height of the end face 1b to flow into each filtering cell 1d without further raising the air A.

[0153] As a result, in the water treatment system 100 of this modified example, for example, it becomes possible to efficiently flow air A into each filtration cell 1d, and it becomes possible to reduce the amount of air A that needs to be supplied from the blower B1.

[0154] Therefore, in the water treatment system 100, for example, it is possible to suppress the occurrence of convection in the water W to be treated in the storage tank 14, and it is possible to promote the settling of the solids S (the solids S discharged from the filtration device 10) in the storage tank 14. Therefore, in the water treatment system 100, it is possible to efficiently suck the solids S using the suction pump P3, for example.

[0155] In addition, in the water treatment system 100, for example, by reducing the amount of air A that needs to be supplied from the blower B1, it is possible to reduce the load on the blower B1 and costs such as power consumption.

[0156] [Modification of Second Control] Next, a modification of the second control will be described.

[0157] The control device 20 may perform backwashing by selectively using a plurality of methods in step S14 of FIG. 14, for example.

[0158] Specifically, for example, when the first timing is reached, the control device 20 may start a backwash (hereinafter also referred to as an increased backwash) that is performed for a longer period of time than a normal backwash (hereinafter also referred to as a normal backwash). The first timing may be, for example, the timing when a predetermined number of normal backwashes have been performed, such as in step S14 of FIG. 14. The first timing may also be the timing when a predetermined time (e.g., several hours) has elapsed since the previous increased backwash. That is, the control device 20 may also perform an increased backwash that uses a larger amount of backwash water than a normal backwash, such as in step S14 of FIG. 14.

[0159] Furthermore, for example, when the second timing is reached, the control device 20 may start backwashing (hereinafter also referred to as low-level backwashing) performed with the water level of the water W to be treated in the storage tank 14 lowered. The second timing may be, for example, a timing when a predetermined time (e.g., several days or several weeks) has elapsed since the previous low-level backwashing. That is, the control device 20 may also perform low-level backwashing, which is performed in a state where each filtration cell 1d is not immersed, in step S14 of FIG. 14, for example.

[0160] Specifically, when performing low-level backwashing, for example, the control device 20 performs a process of discharging the water to be treated W from the storage tank 14 to a drainage pond (not shown) (hereinafter also referred to as a water draining process) to lower the water level of the water to be treated W in the storage tank 14, and then supplies backwash water to backwash the filtration device 10. Then, after performing backwashing on the filtration device 10, the control device 20 performs a process of supplying the water to be treated W to the storage tank 14 (hereinafter also referred to as a water filling process) to raise the water level of the water to be treated W in the storage tank 14 to the water level before the water draining process was performed.

[0161] Furthermore, the control device 20 may start backwashing using backwash water to which a chemical has been added (hereinafter also referred to as chemical-added backwashing) when, for example, a third timing is reached. The third timing may be, for example, a timing when a predetermined time (for example, several weeks or several months) has elapsed since the previous chemical-added backwashing was performed.

[0162] Specifically, for example, when chemical-addition backwashing is performed, the control device 20 performs a drainage process to lower the water level of the water W to be treated in the storage tank 14, then performs a process (hereinafter also referred to as a chemical addition process) in which a chemical (e.g., an acidic chemical) stored in a storage tank (not shown) is added to the backwash water, and then supplies the backwash water to which the chemical has been added to perform backwashing of the filtration device 10. Then, for example, after performing backwashing of the filtration device 10, the control device 20 adds another chemical (e.g., a basic chemical) stored in another storage tank (not shown) to the wastewater discharged from the storage tank 14 (hereinafter also referred to as backwash wastewater) to neutralize the backwash wastewater before discharging it into a wastewater pond (hereinafter also referred to as a neutralization reduction wastewater process), and then performs a water filling process to raise the water level of the water W to the level before the drainage process.

[0163] Furthermore, when the fourth timing is reached, the control device 20 may start backwashing (hereinafter also referred to as chemical backwashing) to clean the inner walls of the filtration device 10 and the storage tank 14 with chemicals. The fourth timing may be, for example, a timing when a predetermined time (e.g., several months or one year) has elapsed since the previous chemical backwashing.

[0164] Specifically, when performing chemical backwashing, the control device 20 performs a draining process to lower the water level of the water W to be treated in the storage tank 14, and then performs a process (hereinafter also referred to as a chemical supply process) to supply a chemical (e.g., an acidic chemical) stored in a storage tank (not shown) to the storage tank 14, thereby immersing the filtration device 10 in the chemical. Then, for example, the control device 20 returns the chemical stored in the storage tank 14 to the storage tank, and then performs backwash water to backwash the filtration device 10, and further performs a neutralization reduction wastewater treatment to discharge the backwash wastewater into a wastewater basin. In this case, the control device 20 may, for example, repeatedly perform the backwashing and neutralization reduction wastewater treatment on the filtration device 10 multiple times. Then, the control device 20 performs a water filling process to raise the water level of the water W to the level before the draining process.

[0165] This allows the control device 20 in this modification to more effectively remove and discharge the solid matter S adhering to the surface or inside of the membrane in each filtration cell 1 d, for example, and therefore the control device 20 can more effectively suppress the occurrence of blockages in each filtration cell 1 d.

[0166] 1: Element 1a: End face 1b: End face 1c: Side face 1d: Filtration cell 1e: Water collection hole 2: Supply pipe 2a: Pipe body 2b: Branch pipe 3: Housing 3a: Housing body 3b: Opening 3c: Opening 3d: Connection part 3e: Skirt part 10: Filtration device 11: Grit chamber 12: Receiving well 13: Mixing chamber 14: Storage tank 15: Clear water reservoir 16: Sludge reservoir 20: Control device 21: First supply unit 22: Second supply unit 23: Discharge unit 100: Water treatment system 201: CPU 202: Memory 203: Communication device 204: Storage medium 205: Bus 210: Program 230: Information storage area A: Air L1: Line L2: Line L3: Line L4: Line L5: Line L6: Line L11: Line L12: Line L13: Line L14: Line S: Solids V1: Valve V2: Valve W: Water to be treated

Claims

1. A water treatment system comprising: a tank for storing water to be treated; and a filtration device installed within the tank, wherein the filtration device has a structure having therein a plurality of filtration cells that produce treated water by filtering the water to be treated, and a collection hole for collecting the treated water produced by the plurality of filtration cells; and further comprising: a first supply unit installed within the tank below the filtration device and capable of supplying air to each of the plurality of filtration cells.

2. The water treatment system of claim 1, wherein the structure is installed so that the water collection hole and the plurality of filtration cells extend vertically.

3. The water treatment system described in claim 1, wherein the filtration device has a skirt portion located below the filtration cell and collecting the air supplied from the first supply portion, and the air collected in the skirt portion flows into the filtration cell.

4. The water treatment system according to claim 1, further comprising a second supply section installed above the filtration device in the tank and capable of supplying the treated water collected by the water collection hole to another device.

5. The water treatment system according to claim 4, wherein the second supply unit supplies backwash water used for backwashing the plurality of filtration cells to the water collection hole.

6. The water treatment system of claim 5, further comprising a discharge section installed below the filtration device within the tank and capable of discharging sludge discharged from the multiple filtration cells in conjunction with backwashing of the multiple filtration cells and settling to the bottom of the tank to another device.

7. The water treatment system of claim 1, further comprising a control device that controls the supply of air by the first supply unit, wherein the control device acquires measurement values ​​for at least one of the water quality of the water to be treated and the differential pressure in the filtration device, and controls the supply of air by the first supply unit in accordance with the acquired measurement values.

8. A method for producing purified water in a water treatment system comprising a tank for storing water to be treated and a filtration device installed within the tank, the filtration device having a structure having therein a plurality of filtration cells that produce treated water by filtering the water to be treated and a water collection hole for collecting the treated water produced by the plurality of filtration cells, and further comprising a first supply unit installed below the filtration device in the tank and capable of supplying air to each of the plurality of filtration cells, the method comprising: obtaining measured values ​​for at least one of the water quality of the water to be treated and the differential pressure in the filtration device; and controlling the supply of air by the first supply unit in accordance with the obtained measured values.

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