Water treatment equipment, control device, operation method, and program

Abstract

The present invention comprises: an RO device (20) to which water being treated is supplied; a main path (30) for supplying treated water from the RO device (20) to a subsequent stage; a circulation path (40) for returning the treated water from the RO device (20) to a stage preceding the RO device (20); a three-way valve (70) for adjusting the flow rate of the treated water from the RO device (20) to the main path (30) and the flow rate of the treated water from the RO device (20) to the circulation path 40; and a control device (100) for controlling the three-way valve (70) so that the amount of change in the flow rate value to the main path (30) is equal to or less than a preset value for a first period when the flow rate of the treated water supplied to the stage subsequent to the RO device (20) is increased to a first supply flow rate, and controlling the three-way valve (70) so that the flow rate value to the main path (30) is equal to the first supply flow rate after the first period has elapsed.

Description

Water treatment equipment, control device, operation method and program

[0001] The present invention relates to a water treatment facility, a control device, an operation method, and a program.

[0002] In order to maintain the quality of treated water from a reverse osmosis membrane device (RO membrane device), a system has been devised in which, if the quality of the water at the outlet of the RO device exceeds a predetermined set value, the treated water from the RO device is returned via a circulation path to a water tank located upstream of the RO device (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2008-229506

[0004] In the above-described system, when the flow rate of treated water supplied from the system is increased, the water quality may deteriorate as the flow rate increases. When a deterioration in water quality is detected, the water to be treated with deteriorated quality is supplied to the subsequent stage. Therefore, when the flow rate of the treated water to be supplied is controlled, the quality of the supplied water may fluctuate.

[0005] An object of the present invention is to provide a water treatment facility, a control device, an operating method, and a program that can suppress fluctuations in water quality even when the flow rate of treated water being supplied is controlled.

[0006] The water treatment facility of the present invention comprises: a reverse osmosis membrane device to which water to be treated is supplied; a first main path for supplying treated water from the reverse osmosis membrane device to a subsequent stage; a first circulation path for returning treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; a first flow control device for adjusting the flow rate of treated water from the reverse osmosis membrane device to the first main path and the flow rate of treated water from the reverse osmosis membrane device to the first circulation path; and a control device for controlling the first flow control device so that, when the flow rate of treated water supplied to the subsequent stage of the reverse osmosis membrane device is increased to a first supply flow rate, the first flow control device is controlled so that the amount of change in the flow rate value to the first main path is equal to or less than a predetermined value for a first period of time, and so that the flow rate value to the first main path becomes the first supply flow rate after the first period has elapsed.

[0007] Furthermore, the control device of the present invention includes: a flow rate value acquisition unit that acquires a first flow rate value to a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, and a second flow rate value to a first circulation path for returning treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; and a flow rate adjustment unit that controls a first flow rate adjustment device that adjusts the flow rate of treated water from the reverse osmosis membrane device to the first main path and the flow rate of treated water from the reverse osmosis membrane device to the first circulation path, wherein when the flow rate of treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, the flow rate adjustment unit controls the first flow rate adjustment device so that the amount of change in the first flow rate value acquired by the flow rate value acquisition unit is equal to or less than a predetermined value for a first period, and after the first period has elapsed, controls the first flow rate adjustment device so that the flow rate value to the first main path becomes the first supply flow rate.

[0008] Furthermore, the operating method of the present invention includes the steps of: acquiring a first flow rate value for a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, the first flow rate value being supplied to the reverse osmosis membrane device; acquiring a second flow rate value for a first circulation path for returning the treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; controlling the flow rate of treated water into the first main path and the first circulation path so that, when the flow rate of treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, the amount of change in the acquired first flow rate value is equal to or less than a predetermined value for a first period of time; and controlling the flow rate of treated water into the first main path and the first circulation path so that, after the first period has elapsed, the flow rate value of treated water into the first main path becomes the first supply flow rate.

[0009] Furthermore, the program of the present invention causes a computer to execute the following steps: acquiring a first flow rate value to a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, the first flow rate value being used to return the treated water from the reverse osmosis membrane device to a subsequent stage of the reverse osmosis membrane device; acquiring a second flow rate value to a first circulation path for returning the treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; when the flow rate of the treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, controlling the flow rates of the treated water to the first main path and the first circulation path so that the amount of change in the acquired first flow rate value is equal to or less than a predetermined value for a first period of time; and controlling the flow rates of the treated water to the first main path and the first circulation path so that the flow rate value to the first main path becomes the first supply flow rate after the first period has elapsed.

[0010] In the present invention, fluctuations in water quality can be suppressed even when the flow rate of the treated water to be supplied is controlled.

[0011] FIG. 5 is a diagram showing an example of a water treatment system to which the water treatment equipment according to the present invention is applied. FIG. 6 is a diagram showing a first embodiment of water treatment equipment applied to the water treatment system shown in FIG. 1. FIG. 7 is a diagram showing an example of components equipped in the control device shown in FIG. 2. FIG. 8 is a flowchart for explaining an example of a method of operating the water treatment equipment shown in FIG. 2. FIG. 9 is a diagram showing a second embodiment of water treatment equipment applied to the water treatment system shown in FIG. 1. FIG. 10 is a diagram showing an example of components equipped in the control device shown in FIG. 11. FIG. 11 is a flowchart for explaining an example of a method of operating the water treatment equipment shown in FIG.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a diagram showing an example of a water treatment system to which the water treatment equipment according to the present invention is applied. The water treatment system shown in FIG. 1 includes a pretreatment system 1, a primary pure water production system 2, and a subsystem 3. The pretreatment system 1 may be a system used in a general water treatment system. The pretreatment system 1 is a water treatment equipment that removes impurities such as turbidity and TOC (total organic carbon) so that treated water of suitable quality can be supplied to downstream equipment. The primary pure water production system 2 is a water treatment equipment that performs a predetermined treatment on the treated water treated in the pretreatment system 1 and supplies the treated water to the subsystem 3. The subsystem 3 may be a secondary pure water production system used in a general water treatment system. The subsystem 3 is a water treatment equipment that removes trace amounts of ions and total organic carbon that could not be completely removed in the primary pure water production system 2. The water treatment equipment according to the present invention can be used for pure water production, ultrapure water production, wastewater recovery, sewage reuse, and seawater desalination. In particular, the water treatment facility according to the present invention is suitable for use in producing pure water and ultrapure water, which require high-purity water quality. (First embodiment)

[0014] Fig. 2 is a diagram showing a first embodiment of a water treatment facility that can be applied to the water treatment system shown in Fig. 1. The water treatment facility in this embodiment is provided in the primary pure water producing system 2 shown in Fig. 1. As shown in Fig. 2, the water treatment facility that can be applied to the water treatment system shown in Fig. 1 includes an RO water tank 10, an RO device 20, a main path 30, a circulation path 40, flow meters 50 and 60, a three-way valve 70, a water quality measuring device 80, and a control device 100.

[0015] The RO water tank 10 is a first water tank that stores the water to be treated that is to be supplied to the RO device 20. The water to be treated stored in the RO water tank 10 is a liquid (water to be treated) that has been treated in the pretreatment system 1. The water to be treated stored in the RO water tank 10 is pumped up using, for example, a pump (not shown) and supplied to the RO device 20.

[0016] The RO device 20 is, for example, a reverse osmosis membrane device that separates ions and TOC from the water to be treated supplied from the RO water tank 10 and divides the water to be treated into permeate and concentrated water. The RO device 20 may be a device in which multiple RO devices are arranged in series.

[0017] The three-way valve 70 is a first flow control device that adjusts the flow rate of treated water (permeate) from the RO device 20 to the main path 30 and the flow rate of treated water (permeate) from the RO device 20 to the circulation path 40. The three-way valve 70 adjusts the flow rate based on a control signal from the control device 100. Note that, in order to control the flow of treated water (permeate) from the RO device 20 to each of the main path 30 and the circulation path 40, an inverter-controlled pump may be used as the first flow control device instead of the three-way valve 70. The main path 30 is a first main path that passes treated water (permeate) from the RO device 20 to a downstream water treatment device or subsystem 3 provided in the primary pure water manufacturing system 2. The circulation path 40 is a first circulation path that returns treated water (permeate) from the RO device 20 to the RO water tank 10 located upstream of the RO device 20.

[0018] The flow meter 50 measures the flow rate of the treated water flowing from the three-way valve 70 to the main path 30. The flow meter 50 notifies the control device 100 of a flow rate value indicating the measured flow rate. The flow meter 60 measures the flow rate of the treated water flowing from the three-way valve 70 to the circulation path 40. The flow meter 60 notifies the control device 100 of a flow rate value indicating the measured flow rate.

[0019] The water quality measuring device 80 is a first water quality measuring device that measures the water quality of the treated water (permeate) from the RO device 20. The water quality measuring device 80 notifies the control device 100 of a water quality value indicating the measured water quality. Examples of the water quality measured by the water quality measuring device 80 include the ion (particularly boron) concentration, electrical conductivity, and particle count of the treated water.

[0020] The control device 100 controls the three-way valve 70 based on the flow rate values ​​notified from the flow meters 50 and 60. The control device 100 also controls the three-way valve 70 based on the water quality value notified from the water quality measuring device 80.

[0021] Fig. 3 is a diagram showing an example of components included in the control device 100 shown in Fig. 2. As shown in Fig. 3, the control device 100 shown in Fig. 2 has a flow value acquisition unit 110 and a flow rate adjustment unit 120. Note that Fig. 3 shows only the main components related to this embodiment among the components included in the control device 100 shown in Fig. 2.

[0022] The flow rate value acquiring unit 110 acquires the flow rate values ​​notified from the flow meters 50 and 60. The flow rate value acquiring unit 110 notifies the flow rate adjusting unit 120 of the acquired flow rate values.

[0023] The flow rate adjustment unit 120 controls the three-way valve 70 based on the flow rate value notified by the flow rate value acquisition unit 110 to adjust the flow rate of the treated water passed from the RO device 20 to the main path 30 and the flow rate of the treated water passed from the RO device 20 to the circulation path 40. Specifically, when the flow rate of the treated water supplied from the RO device 20 to the downstream stage via the main path 30 is increased to a first supply flow rate, the flow rate adjustment unit 120 controls the three-way valve 70 so that the amount of change in the flow rate value (first flow rate value) of the treated water passed from the RO device 20 to the main path 30 is equal to or less than a preset value for a predetermined period (first period). At this time, the flow rate value (first flow rate value) of the treated water passed from the RO device 20 to the main path 30 is the value notified by the flow rate value acquisition unit 110. Needless to say, at this time, the flow rate of the untreated water supplied to the RO device 20 is increased so as to increase the amount of treated water from the RO device 20. Therefore, the flow rate adjustment unit 120 increases the amount of treated water passed from the RO device 20 to the circulation path 40, and controls the three-way valve 70 so that the change in the flow rate of the treated water passed from the RO device 20 to the main path 30 is equal to or less than a preset value. After a predetermined period (first period) has elapsed, the flow rate adjustment unit 120 controls the three-way valve 70 so that the flow rate of the treated water passed from the RO device 20 to the main path 30, i.e., the flow rate value notified from the flow meter 50, becomes the first supply flow rate. To make the flow rate value notified from the flow meter 50 the first supply flow rate, the flow rate adjustment unit 120 controls the three-way valve 70 so that the amount of treated water passed from the RO device 20 to the circulation path 40 decreases, and the amount of treated water passed from the RO device 20 to the main path 30 increases. This predetermined period (first period) is set in advance. This predetermined period (first period) may be, for example, a time measured using a timer or the like, or may be the time until the water quality value notified from the water quality measuring instrument 80 satisfies the first condition. Here, the first condition may be, for example, a condition that the water quality value notified from the water quality measuring instrument 80 is equal to or less than a predetermined threshold, or a condition that the fluctuation range per unit time of the water quality value notified from the water quality measuring instrument 80 is equal to or less than a predetermined range.

[0024] The following describes a method for operating the water treatment facility shown in Fig. 2. Fig. 4 is a flowchart for explaining an example of a method for operating the water treatment facility shown in Fig. 2. As described above, this process is performed when the flow rate of treated water supplied from the RO device 20 to the subsequent stage via the main path 30 is increased to the first supply flow rate.

[0025] First, from the timing at which the flow rate of the untreated water supplied to the RO device 20 is increased, or from a timing before the timing at which the flow rate of the untreated water supplied to the RO device 20 is increased, the flow rate adjustment unit 120 controls the three-way valve 70 so that the amount of change in the flow rate value (first flow rate value) of the treated water passed from the RO device 20 to the main path 30, notified by the flow rate value acquisition unit 110, is equal to or less than a preset value for a predetermined period (first period) (step S1). In order to ensure that the amount of change in the flow rate value (first flow rate value) of the treated water passed from the RO device 20 to the main path 30 is equal to or less than a preset value for a predetermined period (first period), the flow rate adjustment unit 120 controls the three-way valve 70 to increase the flow rate of the treated water passed through the circulation path 40, as described above.

[0026] Thereafter, the flow rate adjusting unit 120 determines whether the water quality value notified by the water quality measuring device 80 is stable (step S2). Specifically, for example, the flow rate adjusting unit 120 determines whether the fluctuation range per unit time of the water quality value notified by the water quality measuring device 80 is equal to or less than a predetermined range.

[0027] If the flow rate adjuster 120 determines that the water quality value notified by the water quality measuring instrument 80 is stable, it controls the three-way valve 70 to decrease the amount of treated water passed from the RO device 20 to the circulation path 40 and increase the amount of treated water passed from the RO device 20 to the main path 30 (step S3). Then, the flow rate adjuster 120 controls the three-way valve 70 so that the flow rate value of the treated water passed from the RO device 20 to the main path 30, i.e., the flow rate value notified by the flow meter 50, finally becomes the first supply flow rate.

[0028] In this manner, in this embodiment, when the flow rate of treated water supplied from the RO device 20 to the subsequent stage via the main path 30 is increased, a portion of the treated water from the RO device 20 is returned to the previous stage of the RO device 20 via the circulation path 40. After a predetermined period of time has elapsed, the flow of treated water from the RO device 20 to the circulation path 40 is reduced, and the flow of water to the main path 30 is increased. Therefore, when the flow rate of treated water supplied from the RO device 20 to the subsequent stage is increased, by providing a process of circulating the water using the circulation path, the treated water can be supplied after its quality has stabilized, and fluctuations in water quality due to an increase in the flow rate of the treated water supplied can be suppressed. (Second Embodiment)

[0029] Fig. 5 is a diagram showing a second embodiment of a water treatment facility that can be applied to the water treatment system shown in Fig. 1. The water treatment facility in this embodiment is provided in the primary pure water producing system 2 shown in Fig. 1. As shown in Fig. 5, the water treatment facility that can be applied to the water treatment system shown in Fig. 1 includes an RO water tank 10, an RO device 20, main paths 30 and 31, circulation paths 40 and 41, flow meters 50, 51, 60 and 61, three-way valves 70 and 71, water quality measuring devices 80 and 81, an EDI water tank 11, an EDI device 21, and a control device 101. The RO water tank 10, the RO device 20, the main path 30, the circulation path 40, the flow meters 50 and 60, the three-way valve 70, and the water quality measuring device 80 are the same as those in the first embodiment.

[0030] The EDI water tank 11 is a second water tank that stores treated water (permeate of the RO device 20) that is treated in the RO device 20 and supplied to the EDI device 21. The treated water stored in the EDI water tank 11 is pumped up using, for example, a pump (not shown) and supplied to the EDI device 21.

[0031] The EDI device 21 is an electrodeionized water production apparatus (water treatment device) having a deionization compartment, a concentration compartment, and an electrode compartment, which are separated by a cation exchange membrane and an anion exchange membrane. A direct current is passed through the EDI device 21, and ions contained in the treated water supplied to the EDI device 21 are removed in the deionization compartment, while the ion exchange resin is continuously regenerated. The treated water from which ions have been removed in the EDI device 21 is discharged to a subsequent stage as deionized water. Meanwhile, a portion of the treated water supplied to the EDI device 21 is sent to the concentration compartment of the EDI device 21 and discharged from the EDI device 21 to the outside of the system as concentrated water with concentrated ions.

[0032] The three-way valve 71 is a second flow control device that adjusts the flow rate of treated water (desalinated water) from the EDI device 21 to the main path 31 and the flow rate of treated water (desalinated water) from the EDI device 21 to the circulation path 41. The three-way valve 71 adjusts the flow rate based on a control signal from the control device 101. Note that, in place of the three-way valve 71, an inverter-controlled pump may be used as the second flow control device to control the flow of treated water (desalinated water) from the EDI device 21 to the main path 31 and the circulation path 41. The main path 31 is a second main path that passes treated water (desalinated water) from the EDI device 21 to a downstream water treatment device or subsystem 3 provided in the primary pure water manufacturing system 2. The circulation path 41 is a second circulation path that returns treated water (desalinated water) from the EDI device 21 to the EDI water tank 11 provided downstream of the RO device 20 and upstream of the EDI device 21.

[0033] Flow meter 51 measures the flow rate of the treated water flowing from three-way valve 71 to main path 31. Flow meter 51 notifies control device 101 of a flow rate value indicating the measured flow rate. Flow meter 61 measures the flow rate of the treated water flowing from three-way valve 71 to circulation path 41. Flow meter 61 notifies control device 101 of a flow rate value indicating the measured flow rate.

[0034] The water quality measuring instrument 81 is a second water quality measuring instrument that measures the quality of the treated water (desalinated water) from the EDI device 21. The water quality measuring instrument 81 notifies the control device 101 of a water quality value indicating the measured water quality. Examples of the water quality measured by the water quality measuring instrument 81 include the ion (particularly boron) concentration, electrical conductivity, and particle count of the treated water.

[0035] The control device 101 controls the three-way valve 71 based on the flow rate values ​​notified from the flow meters 51 and 61. The control device 101 also controls the three-way valve 71 based on the water quality value notified from the water quality measuring device 81.

[0036] Fig. 6 is a diagram showing an example of components included in the control device 101 shown in Fig. 5. As shown in Fig. 6, the control device 101 shown in Fig. 5 has a flow rate value acquisition unit 111 and a flow rate adjustment unit 121. Note that Fig. 6 shows only the main components related to this embodiment among the components included in the control device 101 shown in Fig. 5.

[0037] The flow rate value acquisition unit 111 acquires the flow rate values ​​notified from the flow meters 50, 51, 60, and 61. The flow rate value acquisition unit 111 notifies the flow rate adjustment unit 121 of the acquired flow rate values.

[0038] Based on the flow rate value notified by the flow rate value acquisition unit 111, the flow rate adjustment unit 121 controls the three-way valve 71 to adjust the flow rate of the treated water passed from the EDI device 21 to the main path 31 and the flow rate of the treated water passed from the EDI device 21 to the circulation path 41. Specifically, when the flow rate of the treated water supplied from the RO device 20 to the downstream stage via the main path 30, the EDI device 21, and the main path 31 is increased to the first supply flow rate, the flow rate adjustment unit 121 controls the three-way valve 71 so that the amount of change in the flow rate value (second flow rate value) of the treated water passed from the EDI device 21 to the main path 31 is equal to or less than a preset value for a predetermined period (second period). The flow rate value (second flow rate value) of the treated water passed from the EDI device 21 to the main path 31 at this time is the value notified by the flow rate value acquisition unit 111. At this time, the flow rate adjustment unit 121 increases the amount of treated water passed from the EDI device 21 to the circulation path 41 and controls the three-way valve 71 so that the change in the flow rate of treated water passed from the EDI device 21 to the main path 31 is equal to or less than a preset value. After a predetermined period (second period) has elapsed, the flow rate adjustment unit 121 controls the three-way valve 71 so that the flow rate of treated water passed from the EDI device 21 to the main path 31, i.e., the flow rate value notified from the flow meter 51, becomes the first supply flow rate. To make the flow rate value notified from the flow meter 51 the first supply flow rate, the flow rate adjustment unit 121 controls the three-way valve 71 so that the amount of treated water passed from the EDI device 21 to the circulation path 41 decreases and the amount of treated water passed from the EDI device 21 to the main path 31 increases. This predetermined period (second period) is set in advance. This predetermined period (second period) may be, for example, a time measured using a timer or the like, or may be the time until the water quality value notified from the water quality measuring instrument 81 satisfies the second condition. Here, the second condition may be, for example, a condition that the water quality value notified from the water quality measuring instrument 81 is equal to or less than a predetermined threshold, or a condition that the fluctuation range per unit time of the water quality value notified from the water quality measuring instrument 81 is equal to or less than a predetermined range.

[0039] The following describes a method for operating the water treatment facility shown in Fig. 5. Fig. 7 is a flowchart for explaining an example of a method for operating the water treatment facility shown in Fig. 5. As described above, this process is performed when the flow rate of treated water supplied from the RO device 20 to the subsequent stage via the main path 30, the EDI device 21, and the main path 31 is increased to the second supply flow rate.

[0040] First, from the timing at which the flow rate of the treated water supplied to the RO device 20 is increased, or from a timing before the timing at which the flow rate of the treated water supplied to the RO device 20 is increased, the flow rate adjustment unit 121 controls the three-way valve 71 so that the amount of change in the flow rate value (second flow rate value) of the treated water passed from the EDI device 21 to the main path 31, notified by the flow rate value acquisition unit 111, is equal to or less than a preset value for a predetermined period (second period) (step S11). In order to ensure that the amount of change in the flow rate value (second flow rate value) of the treated water passed from the EDI device 21 to the main path 31 is equal to or less than a preset value for a predetermined period (second period), the flow rate adjustment unit 121 controls the three-way valve 71 to increase the flow rate of the treated water passed through the circulation path 41, as described above.

[0041] Thereafter, the flow rate adjuster 121 determines whether the water quality value notified from the water quality measuring instrument 81 is stable (step S12). Specifically, for example, the flow rate adjuster 121 determines whether the fluctuation range per unit time of the water quality value notified from the water quality measuring instrument 81 is equal to or less than a predetermined range.

[0042] If the flow rate adjuster 121 determines that the water quality value notified by the water quality measuring instrument 81 is stable, it controls the three-way valve 71 to decrease the amount of treated water passed from the EDI device 21 to the circulation path 41 and increase the amount of treated water passed from the EDI device 21 to the main path 31 (step S13). Then, the flow rate adjuster 121 controls the three-way valve 70 so that the flow rate value of the treated water passed from the EDI device 21 to the main path 31, i.e., the flow rate value notified by the flow meter 51, finally becomes the second supply flow rate.

[0043] Thus, in this embodiment, when the flow rate of treated water supplied from the RO device 20 to the subsequent stages via the main path 30, the EDI device 21, and the main path 31 is increased, a portion of the treated water from the EDI device 21 is returned to the stage upstream of the EDI device 21 via the circulation path 41. After a predetermined period of time has elapsed, the flow of treated water from the EDI device 21 to the circulation path 41 is reduced, and the flow of water to the main path 31 is increased. Therefore, when the flow rate of treated water supplied from the RO device 20 to the subsequent stages of the EDI device 21 is increased, by providing a process of circulating using the circulation path, the treated water can be supplied after the water quality has stabilized, and fluctuations in water quality due to an increase in the flow rate of the treated water supplied can be suppressed.

[0044] In this embodiment, as in the first embodiment, the control device 101 may control the three-way valve 70 based on the flow rate values ​​measured by the flow meters 50 and 60. The control device 101 may also control both the three-way valve 70 based on the flow rate values ​​measured by the flow meters 50 and 60 and the three-way valve 71 based on the flow rate values ​​measured by the flow meters 51 and 61. In addition, an RO device or an ultraviolet oxidation device (Uvox) may be provided instead of the EDI device 21.

[0045] Although the above description has been given by allocating each function (process) to each component, this allocation is not limited to the above. Furthermore, the configuration of the components is also not limited to the above-described form, which is merely an example.

[0046] The processes performed by the control devices 100 and 101 may be performed by logic circuits that are individually designed for each purpose. Alternatively, computer programs (hereinafter referred to as programs) that describe the process procedures may be recorded on recording media that can be read by the control devices 100 and 101, and the programs recorded on the recording media may be read and executed by the control devices 100 and 101. The recording media readable by each of the control devices 100 and 101 include removable recording media such as floppy (registered trademark) disks, magneto-optical disks, DVDs (Digital Versatile Discs), CDs (Compact Discs), Blu-ray (registered trademark) Discs, USB (Universal Serial Bus) memories, and SD cards, as well as memories such as ROMs (Read Only Memory) and RAMs (Random Access Memory) built into each of the control devices 100 and 101, and HDDs (Hard Disc Drives). The programs recorded on these recording media are read by a CPU (not shown) provided in each of the control devices 100 and 101, and the same processing as described above is performed under the control of the CPU. Here, the CPU operates as a computer that executes a program read from a recording medium on which the program is recorded.

[0047] This application claims priority based on Japanese Patent Application No. 2024-135696, filed August 15, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0048] REFERENCE SIGNS LIST 1 Pretreatment system 2 Primary pure water production system 3 Subsystem 10 RO water tank 11 EDI water tank 20 RO device 21 EDI device 30, 31 Main path 40, 41 Circulation path 50, 51, 60, 61 Flow meter 70, 71 Three-way valve 80, 81 Water quality measuring device 100, 101 Control device 110, 111 Flow value acquisition unit 120, 121 Flow rate adjustment unit

Claims

1. A water treatment facility comprising: a reverse osmosis membrane device to which water to be treated is supplied; a first main path for supplying treated water from said reverse osmosis membrane device to a subsequent stage; a first circulation path for returning treated water from said reverse osmosis membrane device to a previous stage of said reverse osmosis membrane device; a first flow control device for adjusting the flow rate of treated water from said reverse osmosis membrane device to said first main path and the flow rate of treated water from said reverse osmosis membrane device to said first circulation path; and a control device for controlling said first flow control device so that, when the flow rate of treated water supplied to the subsequent stage of the reverse osmosis membrane device is increased to a first supply flow rate, the amount of change in the flow rate value to said first main path is equal to or less than a predetermined value for a first period of time, and for controlling said first flow control device so that the flow rate value to said first main path becomes the first supply flow rate after the first period has elapsed.

2. A water treatment facility as described in claim 1, further comprising a first water quality measuring device that measures the quality of treated water from the reverse osmosis membrane device, and wherein the control device controls the first flow rate adjustment device so that the flow rate value to the first main path becomes the first supply flow rate when the measurement value measured by the first water quality measuring device satisfies a first condition.

3. The water treatment facility according to claim 1 or 2, wherein the first flow rate control device is a three-way valve.

4. A water treatment facility as claimed in claim 1 or 2, comprising: a water treatment device provided downstream of the reverse osmosis membrane device; a second main path for supplying treated water from the water treatment device to the downstream stage; a second circulation path for returning treated water from the water treatment device to the downstream stage of the reverse osmosis membrane device and the upstream stage of the water treatment device; and a second flow rate control device for adjusting the flow rate of treated water from the water treatment device to the second main path and the flow rate of treated water from the water treatment device to the second circulation path, wherein the control device, when increasing the flow rate of treated water supplied to the downstream stage of the water treatment device to a second supply flow rate, controls the second flow rate control device so that the amount of change in the flow rate value to the second main path is equal to or less than a preset value for a second period, and after the second period has elapsed, controls the second flow rate control device so that the flow rate value to the second main path becomes the second supply flow rate.

5. A water treatment facility as described in claim 4, further comprising a second water quality measuring device that measures the quality of treated water from the water treatment device, and wherein the control device controls the flow rate adjustment device so that the flow rate value to the second main path becomes the second supply flow rate when the measurement value measured by the second water quality measuring device satisfies a second condition.

6. The water treatment facility according to claim 4, wherein the second flow rate adjusting device is a three-way valve.

7. A control device comprising: a flow rate value acquisition unit that acquires a first flow rate value to a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, and a second flow rate value to a first circulation path for returning treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; and a flow rate adjustment unit that controls a first flow rate adjustment device that adjusts the flow rate of treated water from the reverse osmosis membrane device to the first main path and the flow rate of treated water from the reverse osmosis membrane device to the first circulation path, wherein when the flow rate of treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, the flow rate adjustment unit controls the first flow rate adjustment device so that the amount of change in the first flow rate value acquired by the flow rate value acquisition unit is equal to or less than a predetermined value for a first period, and after the first period has elapsed, controls the first flow rate adjustment device so that the flow rate value to the first main path becomes the first supply flow rate.

8. An operating method comprising the steps of: acquiring a first flow rate value for a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, the first flow rate value being supplied to the reverse osmosis membrane device; acquiring a second flow rate value for a first circulation path for returning the treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; controlling the flow rate of treated water into the first main path and the first circulation path so that, when the flow rate of treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, the amount of change in the acquired first flow rate value is equal to or less than a predetermined value for a first period of time; and controlling the flow rate of treated water into the first main path and the first circulation path so that, after the first period has elapsed, the flow rate value of the first main path becomes the first supply flow rate.

9. A program for causing a computer to execute the following steps: acquiring a first flow rate value to a first main path for supplying treated water from a reverse osmosis membrane device to a subsequent stage, to which water to be treated is supplied; acquiring a second flow rate value to a first circulation path for returning the treated water from the reverse osmosis membrane device to a previous stage of the reverse osmosis membrane device; controlling the flow rate of treated water to the first main path and the first circulation path so that, when the flow rate of treated water supplied from the reverse osmosis membrane device to the subsequent stage is increased to a first supply flow rate, the amount of change in the acquired first flow rate value is equal to or less than a predetermined value for a first period of time; and controlling the flow rate of treated water to the first main path and the first circulation path so that the flow rate value to the first main path becomes the first supply flow rate after the first period has elapsed.

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