Water treatment system and method for operating the water treatment system

Abstract

To easily shorten the operation stop time of a system associated with the regeneration of a device.SOLUTION: A water treatment system for treating water of interest, equipped with a membrane separator and an ion exchanger, has first piping for simultaneously supplying a chemical solution to the membrane separator and the ion exchanger in parallel, first valve groups 510, 530 provided in the first piping, and a controller 600 for controlling the opening and closing of the first valve groups 510, 530.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a water treatment system and a method for operating a water treatment system. [Background technology]

[0002] In water treatment systems, degassing devices equipped with degassing membranes are used to remove dissolved gases (CO2 and O2) from the water being treated. Water treatment devices such as ion exchange resins, reverse osmosis membranes, and ultrafiltration membranes are also used to remove ions and total organic carbon (TOC) from the water being treated. A water treatment system is constructed by combining multiple degassing devices and water treatment devices.

[0003] As degassing membranes are used, clogging, or so-called fouling, occurs due to the adhesion and accumulation of organic and inorganic matter on the membrane surface. Once fouling occurs, the degassing performance and water permeability of the degassing device decline. To remove the attached and accumulated organic and inorganic matter, the degassing membranes must be periodically cleaned. Chemicals such as acids and alkalis are used to clean the degassing membranes (see, for example, Patent Document 1).

[0004] Water treatment devices also require periodic cleaning and regeneration. For example, ion exchange resins require periodic regeneration using chemical solutions. Furthermore, membranes such as reverse osmosis membranes and ultrafiltration membranes are cleaned using chemical solutions to restore membrane performance that has been reduced by fouling. A technology has also been proposed in which the chemical solutions used to clean one water treatment device are used to clean another water treatment device (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-90249 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-22447 Summary of the Invention [Problem to be solved by the invention]

[0006] The cleaning and regeneration of the above-mentioned equipment is performed for each degassing device and water treatment device. When cleaning or regenerating a degassing device or water treatment device, the operation of the degassing device or water treatment device or a system incorporating these devices is often stopped, and the device to be cleaned or regenerated is isolated from the main line. Therefore, frequent cleaning and regeneration can significantly reduce the system's operating rate. Furthermore, the technology described in Patent Document 2 requires a large number of ancillary facilities, making the system configuration complex.

[0007] An object of the present invention is to provide a water treatment system and a method for operating a water treatment system that can easily shorten the shutdown time of the system due to the regeneration of the equipment. [Means for solving the problem]

[0008] The water treatment system of the present invention comprises: A water treatment system including a membrane separation device and an ion exchange device, a first pipe for simultaneously supplying the chemical solution to the membrane separation device and the ion exchange device in parallel; a first valve group provided in the first pipe; and a control device that controls the opening and closing of the first valve group.

[0009] In addition, the water treatment system of the present invention includes: A water treatment system including a membrane separation device and an ion exchange device, a first pipe for supplying a chemical solution to the membrane separation device; a second pipe for supplying the chemical solution passed through the membrane separation device to the ion exchange device; a first valve group provided in the first pipe; a second valve group provided in the second pipe; a control device that controls opening and closing of the first valve group and the second valve group, The control device controls the opening and closing of the second valve group so that the chemical solution passed through the membrane separation device is supplied to the ion exchange device.

[0010] Further, the method for operating a water treatment system of the present invention includes the steps of: A method for operating a water treatment system including a membrane separation device and an ion exchange device, comprising: a water passing step of passing the water to be treated through the membrane separation device and the ion exchange device by controlling the opening and closing of valves arranged in piping; A chemical supplying step is carried out in which the opening and closing of the valve is controlled based on a predetermined timing to simultaneously supply the chemical solution to the membrane separation device and the ion exchange device in parallel. [Effects of the Invention]

[0011] In the present invention, the system downtime associated with device regeneration can be easily reduced. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a general water treatment system. [Figure 2] 1 is a diagram showing a first embodiment of a water treatment system of the present invention. [Figure 3] 3 is a flowchart illustrating a first example of an operating method for the water treatment system shown in FIG. 2. [Figure 4] 10 is a flowchart illustrating a second example of the operating method for the water treatment system shown in FIG. [Figure 5] FIG. 2 is a diagram showing a second embodiment of the water treatment system of the present invention. [Figure 6] 6 is a flowchart illustrating an example of an operating method for the water treatment system shown in FIG. 5. [Figure 7] FIG. 10 is a diagram showing a third embodiment of the water treatment system of the present invention. [Figure 8]8 is a flowchart illustrating an example of an operating method for the water treatment system shown in FIG. 7. [Figure 9] FIG. 10 is a diagram showing a fourth embodiment of the water treatment system of the present invention. [Figure 10] 10 is a flowchart illustrating an example of an operating method for the water treatment system shown in FIG. [Figure 11] 1 is a table showing the results of Examples 1 and 2 and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an example of the configuration of a typical water treatment system. The water treatment system illustrated in FIG. 1 includes a raw water tank 100, a degassing device 200, and a water treatment device 300. The raw water tank 100 is a tank in which raw water, which is the liquid to be treated, is stored. The liquid stored in the raw water tank 100 is supplied from the raw water tank 100 to the degassing device 200 using, for example, a pump during a water passing step in which the raw water is passed through. The degassing device 200 removes dissolved gases contained in the liquid supplied from the raw water tank 100. For example, the degassing device 200 is a membrane degassing device that uses a polymer membrane to remove dissolved gases such as dissolved oxygen and free carbon dioxide by passing them through the membrane. Note that a membrane degassing device that removes free carbon dioxide is sometimes called a decarbonation membrane device. The type of dissolved gas removed by the membrane degassing device of the present invention is not particularly limited. For example, the membrane degassing apparatus of the present invention may be one that removes dissolved gases regardless of their type, or one that removes specific types of dissolved gases. The liquid from which dissolved gases have been removed by the degassing apparatus 200 is supplied to the water treatment device 300 in the water passing step. The water treatment device 300 is connected in series with the degassing apparatus 200 and removes impurities contained in the liquid supplied from the degassing apparatus 200. The water treatment device 300 may be, for example, an ion exchange device filled with ion exchange resin. As the ion exchange resin, a cation exchange resin that removes cation components in water or an anion exchange resin that removes anion components in water can be used. The water treatment device 300 may be a UF (ultrafiltration) device or an RO (reverse osmosis) device. The liquid (treated water) treated in the water treatment device 300 may be stored in a treated water tank or treated by another unit operation, as necessary, in the water passing step. Depending on the quality of the raw water and the purity of the treated water, such water can be used as pure water or ultrapure water for manufacturing electronic components such as semiconductors, or as general-purpose water within the factory. Note that other water treatment devices (for example, a cation exchange resin device filled with a cation exchange resin) may be disposed between the raw water tank 100 and the degassing device 200.

[0014] The present invention described below relates to the regeneration and cleaning of components used in a water treatment system that performs a water passing step as shown in FIG. (First embodiment)

[0015] FIG. 2 is a diagram showing a first embodiment of a water treatment system according to the present invention. As shown in FIG. 2, the water treatment system according to this embodiment includes a raw water tank 100, a degassing device 200 (membrane separation device), and a water treatment device 300 (ion exchange device). These components are the same as those shown in FIG. 1. The membrane separation device uses a separation membrane to remove ions, TOC, suspended solids (SS), gas components, and the like from raw water. Examples of separation membranes include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and degassing membranes (decarbonation membranes). Furthermore, as shown in FIG. 2, the water treatment system according to this embodiment includes a chemical tank 400, multiple on-off valves (valves 510, 520, 530, and 540), and a control device 600. Valve 510 and valve 530 constitute a first valve group. These components are connected to each other via piping. In this embodiment, the piping from the chemical tank 400 to the degassing device 200 and the water treatment device 300 constitutes the first piping. The piping from the deaerator 200 to the water treatment device 300 via the valve 520 and the valve 530 is the second piping.

[0016] The chemical tank 400 is a tank that stores a chemical solution for regenerating the degassing device 200 and the water treatment device 300. When the water treatment device 300 is filled with an anion exchange resin, the chemical solution stored in the chemical tank 400 is, for example, an alkaline chemical solution such as a sodium hydroxide solution or a potassium hydroxide solution. When the water treatment device 300 is filled with a cation exchange resin, the chemical solution stored in the chemical tank 400 is, for example, an acidic chemical solution such as hydrochloric acid or sulfuric acid. The chemical solution stored in the chemical tank 400 is supplied from the chemical tank 400 to the valves 510 and 530 using, for example, a pump in a chemical supplying step. Instead of supplying the chemical solution stored in the chemical tank 400 to the valves 510 and 530, a chemical solution such as sodium hydroxide may be mixed and adjusted in a line with clear water such as RO-treated water, ion-exchanged water, or pure water, and then supplied to the valves 510 and 530. The chemical from the chemical tank 400 is supplied simultaneously in parallel to the degassing device 200 and the water treatment device 300 via the first pipe. The meaning of "simultaneously" here is not limited to being supplied at exactly the same time, but also includes being supplied at a time difference of less than a predetermined time, as long as the effects of the present invention can be achieved. The same applies to the embodiments described below.

[0017] The control device 600 controls the opening and closing of valves 510, 520, 530, and 540 arranged in paths through which the liquid to be treated, the treated liquid, the chemical solution, and the like flow. During the chemical supplying process, the control device 600 controls the opening and closing of valves 510 and 530 so that the chemical solution supplied from the chemical solution tank 400 is supplied to the degassing device 200 and the water treatment device 300 in parallel. Specifically, the control device 600 controls the opening and closing of valve 510 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical solution from the chemical solution tank 400 is supplied to the degassing device 200. The control device 600 also controls the opening and closing of valve 530 so that the liquid from valve 520 is not supplied to the water treatment device 300 and so that the chemical solution from the chemical solution tank 400 is supplied to the water treatment device 300. Furthermore, the control device 600 controls the opening and closing of valve 520 so that the liquid flowing out from the degassing device 200 flows into a waste path. Furthermore, the control unit 500 controls the opening and closing of the valve 540 so that the liquid flowing out of the water treatment device 300 flows into a waste path.

[0018] The timing of the transition from the water passing process to the chemical passing process may be according to a preset schedule. Alternatively, the timing of the transition from the water passing process to the chemical passing process may be based on the difference between the pressure upstream of the degassing device 200, i.e., the raw water side (the raw water tank 100 side), and the pressure downstream of the degassing device 200, i.e., the treated water side (the water treatment device 300 side). Specifically, when the difference between the pressure on the raw water side of the degassing device 200 and the pressure on the permeation side of the degassing device 200 exceeds a predetermined threshold, the control device 600 controls the opening and closing of the valves 510, 520, 530, and 540 to transition from the water passing process to the chemical passing process.

[0019] The following describes a method for operating the water treatment system shown in Fig. 2. Fig. 3 is a flowchart for explaining a first example of a method for operating the water treatment system shown in Fig. 2.

[0020] First, to perform the water passing step, the control device 600 controls the opening and closing of the valves 510, 520, 530, and 540 so that water is passed from the raw water tank 100 (step S1). Specifically, the control device 600 controls the opening and closing of the valve 510 so that the liquid from the raw water tank 100 is supplied to the degassing device 200. The control device 600 also controls the opening and closing of the valves 520 and 530 so that the liquid from the degassing device 200 is supplied to the water treatment device 300. The control device 600 also controls the opening and closing of the valve 540 so that the liquid from the water treatment device 300 is supplied to the treated water tank.

[0021] The control device 600 controls the opening and closing of the valves 510, 520, 530, and 540 to allow water to pass from the raw water tank 100, and after the water passing step is performed, the control device 600 determines whether it is time to pass the chemical liquid based on a preset schedule (step S2). The timing to pass the chemical liquid is the timing to transition from the water passing step to the chemical passing step.

[0022] When the control device 600 determines that it is time to pass the chemical liquid, it controls the opening and closing of valves 510, 520, 530, and 540 so that the chemical liquid from the chemical liquid tank 400 is supplied in parallel to the degassing device 200 and the water treatment device 300 (step S3). Specifically, the control device 600 controls the opening and closing of valve 510 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical liquid from the chemical liquid tank 400 is supplied to the degassing device 200. The control device 600 also controls the opening and closing of valve 520 so that the chemical liquid from the degassing device 200 flows to a waste path. The control device 600 also controls the opening and closing of valve 530 so that the chemical liquid from the chemical liquid tank 400 is supplied to the water treatment device 300. The control device 600 also controls the opening and closing of valve 540 so that the chemical liquid from the water treatment device 300 flows to a waste path.

[0023] FIG. 4 is a flowchart illustrating a second example of the operating method for the water treatment system shown in FIG.

[0024] First, to perform the water passing step, the control device 600 controls the opening and closing of the valves 510, 520, 530, and 540 so that water is passed from the raw water tank 100 (step S11). Specifically, the control device 600 controls the opening and closing of the valve 510 so that the liquid from the raw water tank 100 is supplied to the degassing device 200. The control device 600 also controls the opening and closing of the valves 520 and 530 so that the liquid from the degassing device 200 is supplied to the water treatment device 300. The control device 600 also controls the opening and closing of the valve 540 so that the liquid from the water treatment device 300 is supplied to the treated water tank.

[0025] The control device 600 controls the opening and closing of the valves 510, 520, 530, and 540 so that water is passed from the raw water tank 100, and after the water passing process is performed, the control device 600 determines whether the difference (differential pressure) between the pressure on the raw water side of the degassing device 200 and the pressure on the permeation side of the degassing device 200 exceeds a predetermined threshold (step S12).

[0026] When the control device 600 determines that the difference (differential pressure) between the pressure on the raw water side of the degassing device 200 and the pressure on the permeate side of the degassing device 200 exceeds a predetermined threshold, the control device 600 controls the opening and closing of valves 510, 520, 530, and 540 so that the chemical from the chemical tank 400 is supplied in parallel to the degassing device 200 and the water treatment device 300 (step S13). Specifically, the control device 600 controls the opening and closing of valve 510 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical from the chemical tank 400 is supplied to the degassing device 200. The control device 600 also controls the opening and closing of valve 520 so that the chemical from the degassing device 200 flows to a waste path. The control device 600 also controls the opening and closing of valve 530 so that the chemical from the chemical tank 400 is supplied to the water treatment device 300. Furthermore, the control device 600 controls the opening and closing of the valve 540 so that the chemical liquid from the water treatment device 300 flows into a path for disposal.

[0027] In addition, when a water treatment system has a redundant configuration with multiple operating systems, it goes without saying that when a system operating in the water flow process shifts from the water flow process to the chemical flow process, the other systems also shift to the water flow process. This also applies to the following embodiments.

[0028] In this manner, in the present embodiment, in the process of passing a chemical solution through the degassing device and the water treatment device that constitute the water treatment system to regenerate the device, the chemical solution is supplied to the degassing device and the water treatment device in parallel, which makes it possible to easily shorten the system downtime associated with the device regeneration.

[0029] 2, a valve may be provided at a position where the chemical tank 400 branches off to the valves 510 and 530, or the path from the chemical tank 400 to the valve 530 may be blocked or eliminated, so that the chemical from the chemical tank 400 is not directly supplied to the valve 530. In this case, in the step of passing the chemical, the chemical from the chemical tank 400 may be supplied to the degassing device 200, and the chemical that has passed through the degassing device 200 may be supplied to the water treatment device 300. This makes it possible to reduce the amount of chemical used in the step of passing the chemical and the amount of chemical discharged. (Second embodiment)

[0030] FIG. 5 is a diagram showing a second embodiment of the water treatment system of the present invention. As shown in FIG. 5, the water treatment system of this embodiment includes raw water tank 100, degassing device 200, and water treatment device 300. These are the same as those in the first embodiment. Furthermore, as shown in FIG. 5, the water treatment system of this embodiment includes chemical tank 400, multiple on-off valves (valves 510, 530, and 540), and control device 601. Valves 510 and 530 form a first valve group. Note that valve 520 of the first embodiment may also be included. Valves 520 and 530 form a second valve group. Valve 530 belongs to both the first valve group and the second valve group. In other words, valve 530 fulfills the role of both the first valve group and the second valve group. When the valve 520 is provided, immediately after the start of the drug passing step, the control device 601 can control the valve 520 to discharge the drug solution passed through the degassing device 200 to the outside of the system. After that, at a predetermined timing, the control device 601 controls the valve 520 to supply the drug solution passed through the degassing device 200 to the valve 530. The predetermined timing can be, for example, When a preset time has elapsed When the TOC value contained in the chemical solution from the degassing device 200 becomes lower than a predetermined threshold value. When the pH value of the chemical solution from the degassing device 200 becomes higher than a predetermined threshold value. When the conductivity of the chemical solution from the degassing device 200 becomes higher than a predetermined threshold value. The reason for this is that in the early stages of the chemical passing process, the chemical passed through the degassing device 200 contains a large amount of the removed contaminants, which may re-contaminate the water treatment device 300. Another reason for this is to prevent the chemical diluted with water contained in the degassing device 200 from flowing into the water treatment device 300.

[0031] Valves 510, 530, and 540 and chemical tank 400 are the same as those in the first embodiment. In this embodiment, the piping from chemical tank 400 to degassing device 200 and water treatment device 300 is the first piping. The piping from degassing device 200 to water treatment device 300 via valve 530 is the second piping.

[0032] The control device 601 controls the opening and closing of valves 510, 530, and 540 provided in paths through which the liquid to be treated, the treated liquid, the chemical solution, and the like flow. During the chemical supplying step, the control device 601 controls the opening and closing of valves 510 and 530 so that the chemical solution supplied from the chemical solution tank 400 is supplied in parallel to the degassing device 200 and the water treatment device 300. Specifically, the control device 601 controls the opening and closing of valve 510 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical solution from the chemical solution tank 400 is supplied to the degassing device 200. The control device 601 also controls the opening and closing of valve 530 so that the chemical solution from the degassing device 200 and the chemical solution from the chemical solution tank 400 are supplied to the water treatment device 300. Furthermore, the control device 601 controls the opening and closing of valve 540 so that the liquid flowing out from the water treatment device 300 flows into a waste path. In this embodiment, when the valve 520 of the first embodiment is provided, the control device 601 controls the opening and closing of the valve 520 so that the chemical liquid flowing out from the degassing device 200 is supplied to the water treatment device 300 (valve 530). At this time, the control device 601 controls the opening and closing of the valves 520 and 530 to either continue the supply of the chemical liquid directly from the chemical liquid tank 400 to the water treatment device 300 via the valve 530, or to cut off the supply of the chemical liquid passed through the degassing device 200 to the water treatment device 300 if the amount of the chemical liquid supplied to the water treatment device 300 is sufficient.

[0033] The timing of transition from the water passing step to the chemical passing step is the same as in the first embodiment.

[0034] The following describes a method for operating the water treatment system shown in Fig. 5. Fig. 6 is a flowchart for explaining an example of a method for operating the water treatment system shown in Fig. 5.

[0035] First, to perform the water passing step, the control device 601 controls the opening and closing of the valves 510, 530, and 540 so that water is passed from the raw water tank 100 (step S21). Specifically, the control device 601 controls the opening and closing of the valve 510 so that the liquid from the raw water tank 100 is supplied to the degassing device 200. The control device 601 also controls the opening and closing of the valve 530 so that the liquid from the degassing device 200 is supplied to the water treatment device 300. The control device 601 also controls the opening and closing of the valve 540 so that the liquid from the water treatment device 300 is supplied to equipment such as a treated water tank provided downstream.

[0036] After the control device 601 controls the opening and closing of the valves 510, 530, and 540 to allow water to pass from the raw water tank 100 and the water passing step is performed, the control device 601 determines whether it is time to pass the chemical liquid based on a preset schedule (step S22). The timing to pass the chemical liquid is the timing to transition from the water passing step to the chemical passing step.

[0037] When the control device 601 determines that it is time to pass the chemical liquid, it controls the opening and closing of valves 510, 530, and 540 so that the chemical liquid from the chemical liquid tank 400 is supplied in parallel to the degassing device 200 and the water treatment device 300 (step S23). Specifically, the control device 601 controls the opening and closing of valve 510 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical liquid from the chemical liquid tank 400 is supplied to the degassing device 200. The control device 601 also controls the opening and closing of valve 530 so that the chemical liquid from the degassing device 200 and the chemical liquid from the chemical liquid tank 400 are supplied to the water treatment device 300. The control device 601 also controls the opening and closing of valve 540 so that the chemical liquid from the water treatment device 300 flows to a waste path. Furthermore, when the valve 520 of the first embodiment is provided, the control device 601 controls the opening and closing of the valve 520 so that the chemical liquid flowing out from the degassing device 200 is also supplied to the water treatment device 300 (valve 530).

[0038] Thus, in this embodiment, in the process of passing a chemical liquid through the degassing device and the water treatment device that constitute the water treatment system to regenerate the device, the chemical liquid is supplied in parallel to the degassing device and the water treatment device. This makes it easy to shorten the system's downtime associated with device regeneration. Furthermore, the chemical liquid passed through the degassing device is supplied to the water treatment device. This reduces the amount of chemical liquid used in the chemical passing process and the amount of chemical liquid discharged. Supplying the chemical liquid passed through the degassing device to the water treatment device also makes it possible to reduce the amount of chemical liquid supplied from the chemical tank to the water treatment device. (Third embodiment)

[0039] FIG. 7 is a diagram showing a third embodiment of the water treatment system of the present invention. As shown in FIG. 7, the water treatment system of this embodiment includes raw water tank 100, degassing device 200, and water treatment device 300. These components are the same as those in the first embodiment. Furthermore, as shown in FIG. 7, the water treatment system of this embodiment includes chemical tank 400, multiple on-off valves (valves 520, 530, 550, and 560), and control device 602. Valves 530 and 550 constitute a first valve group. Valves 550 and 560 constitute a third valve group. Valve 550 belongs to both the first and third valve groups. In other words, valve 550 fulfills the roles of both the first and third valve groups. Immediately after the start of the chemical supply process, control device 602 can control valve 560 to discharge the chemical solution passed through water treatment device 300 to the outside of the system. Thereafter, at a predetermined timing, the control device 602 controls the valve 560 to supply the chemical solution passed through the water treatment device 300 to the valve 550. The predetermined timing may be, for example, When a preset time has elapsed When the TOC value contained in the chemical solution from the water treatment device 300 becomes lower than a predetermined threshold value. When the pH value of the chemical solution from the water treatment device 300 becomes higher than a predetermined threshold value. When the conductivity of the chemical solution from the water treatment device 300 becomes higher than a predetermined threshold value. The reason for this is that in the early stages of the chemical passing process, the chemical passed through the water treatment device 300 contains a large amount of the removed contaminants, which may re-contaminate the degassing device 200. Another reason for this is to prevent the chemical diluted with water contained in the degassing device 200 from flowing into the water treatment device 300.

[0040] Valves 520 and 530 and chemical tank 400 are the same as those in the first embodiment. In this embodiment, the piping from chemical tank 400 to degassing device 200 and water treatment device 300 is the first piping. The piping from degassing device 200 to water treatment device 300 via valves 520 and 530 is the second piping. The piping from water treatment device 300 to degassing device 200 via valves 560 and 550 is the third piping.

[0041] The control device 602 controls the opening and closing of valves 520, 530, 550, and 560 provided in paths through which the liquid to be treated, the treated liquid, the chemical, and the like flow. During the chemical supplying step, the control device 602 controls the opening and closing of valves 520, 530, 550, and 560 so that the chemical supplied from the chemical tank 400 is supplied to the degassing device 200 and the water treatment device 300 in parallel. Specifically, the control device 602 controls the opening and closing of valve 550 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200 and so that the chemical from the chemical tank 400 is supplied to the degassing device 200. At this time, the control device 602 controls valve 550 so that the chemical from the water treatment device 300 via valve 560 is also supplied to the degassing device 200. The control device 602 also controls the opening and closing of valve 530 so that the chemical from the chemical tank 400 is supplied to the water treatment device 300. Furthermore, control device 602 controls the opening and closing of valve 560 so as to supply the chemical liquid flowing out from water treatment device 300 to valve 550. Control device 602 also controls the opening and closing of valve 520 so as to allow the liquid flowing out from degassing device 200 to flow to a waste path. At this time, control device 602 controls the opening and closing of valves 550 and 560 to either continue the supply of the chemical liquid from chemical tank 400 directly to degassing device 200 via valve 550, or to cut off the supply if the amount of chemical liquid passed through water treatment device 300 supplied to degassing device 200 is sufficient.

[0042] The timing of transition from the water passing step to the chemical passing step is the same as in the first embodiment.

[0043] The following describes a method for operating the water treatment system shown in Fig. 7. Fig. 8 is a flowchart for explaining an example of a method for operating the water treatment system shown in Fig. 7.

[0044] First, to perform the water passing step, the control device 602 controls the opening and closing of the valves 520, 530, 550, and 560 so that water is passed from the raw water tank 100 (step S31). Specifically, the control device 602 controls the opening and closing of the valve 550 so that the liquid from the raw water tank 100 is supplied to the degassing device 200. The control device 602 also controls the opening and closing of the valves 520 and 530 so that the liquid from the degassing device 200 is supplied to the water treatment device 300. The control device 602 also controls the opening and closing of the valve 560 so that the liquid from the water treatment device 300 is supplied to the treated water tank.

[0045] The control device 602 controls the opening and closing of the valves 520, 530, 550, and 560 to allow water to pass from the raw water tank 100. After the water passing step is completed, the control device 602 determines whether it is time to pass the chemical liquid based on a preset schedule (step S32). The timing to pass the chemical liquid corresponds to the timing of transition from the water passing step to the chemical passing step.

[0046] When the control device 602 determines that it is time to pass the chemical liquid, it controls the opening and closing of valves 520, 530, 550, and 560 so that the chemical liquid from the chemical liquid tank 400 is supplied to the degassing device 200 and the water treatment device 300 in parallel, and so that the chemical liquid from the water treatment device 300 is supplied to the degassing device 200 via valves 550 and 560 (step S33). Specifically, the control device 602 controls the opening and closing of valve 530 so that the chemical liquid from the chemical liquid tank 400 is supplied to the water treatment device 300. The control device 602 also controls the opening and closing of valve 560 so that the chemical liquid from the water treatment device 300 is supplied to valve 550. The control device 602 also controls the opening and closing of valve 550 so that the liquid from the raw water tank 100 is not supplied to the degassing device 200, and so that the chemical liquid from the chemical liquid tank 400 and the chemical liquid from the water treatment device 300 via valve 560 are supplied to the degassing device 200. Furthermore, the control device 602 controls the opening and closing of the valve 520 so that the chemical liquid from the degassing device 200 flows into a waste path.

[0047] In this manner, in this embodiment, in the process of passing a chemical liquid through the degassing device and the water treatment device that constitute the water treatment system to regenerate the device, the chemical liquid is supplied in parallel to the degassing device and the water treatment device. This makes it easy to shorten the system's downtime associated with device regeneration. Furthermore, the chemical liquid passed through the water treatment device is supplied to the degassing device. This reduces the amount of chemical liquid used in the chemical passing process and the amount of chemical liquid discharged. (Fourth embodiment)

[0048] FIG. 9 is a diagram showing a fourth embodiment of the water treatment system of the present invention. In this embodiment, the operation when transitioning from the chemical feeding process to the cleaning process will be described. As shown in FIG. 9, the water treatment system in this embodiment has raw water tank 100, degassing device 200, and water treatment device 300. These are the same as those in the first embodiment. Furthermore, as shown in FIG. 9, the water treatment system in this embodiment has chemical tank 400, multiple on-off valves (valves 530, 540, 570, and 580), control device 603, and cleaning water tank 700. In this embodiment, valve 530, valve 570, and valve 580 constitute a fourth valve group.

[0049] Valves 530 and 540 and chemical tank 400 are the same as those in the first embodiment. Chemical tank 400 is used in the chemical supplying step performed before the cleaning step, but is not used in the cleaning step. In this embodiment, the cleaning step performed after the chemical supplying step is described as an example, and therefore chemical tank 400 is shown in FIG. 9. In this embodiment, the piping from chemical tank 400 to degassing device 200 and water treatment device 300 is the first piping. Furthermore, the piping from degassing device 200 to water treatment device 300 via valve 530 is the second piping. Furthermore, the piping from cleaning water tank 700 to water treatment device 300 via degassing device 200 is the fourth piping. The piping from valve 570 to degassing device 200 via valve 580 serves as both the first piping and the fourth piping. The pipe from the deaerator 200 to the water treatment device 300 via the valve 530 serves as both the second pipe and the fourth pipe.

[0050] The cleaning water tank 700 is a tank that stores a liquid (cleaning water) used in the cleaning process to clean the degassing device 200 and the water treatment device 300 through which the chemical solution has been passed. As the cleaning water, raw water, RO-treated water, ion-exchanged water, pure water, etc. can be used. When the cleaning water is raw water, the cleaning water tank can also serve as a raw water tank.

[0051] Control device 603 controls the opening and closing of valves 530, 540, 570, and 580 provided in paths through which the liquid to be treated, the treated liquid, the chemical solution, cleaning water, etc. flow. Control device 602 controls the opening and closing of valves 530, 540, 570, and 580 so that, in the cleaning process following the chemical passing process, cleaning water supplied from cleaning water tank 700 is supplied to degassing device 200 and cleaning water passed through degassing device 200 is supplied to water treatment device 300. Specifically, when the chemical passing process ends and the cleaning process starts, control device 603 controls the opening and closing of valve 570 so that the chemical solution from chemical solution tank 400 is not supplied to degassing device 200 via valve 580 and so that cleaning water from cleaning water tank 700 is supplied to degassing device 200 via valve 580. Furthermore, the control device 603 controls the opening and closing of valve 580 so that liquid from raw water tank 100 is not supplied to degassing device 200 and so that cleaning water from valve 570 is supplied to degassing device 200. Furthermore, the control device 603 controls the opening and closing of valve 530 so that chemical liquid from chemical liquid tank 400 is not supplied to water treatment device 300 and so that cleaning water from degassing device 200 is supplied to water treatment device 300. Furthermore, the control device 603 controls the opening and closing of valve 540 so that cleaning water from water treatment device 300 flows to a waste path.

[0052] The timing of transition from the drug supplying process to the cleaning process may be according to a preset schedule, or may be when the amount of drug supplied from the drug supplying process tank 400 reaches a preset amount.

[0053] The following describes a method for operating the water treatment system shown in Fig. 9. Fig. 10 is a flowchart for explaining an example of a method for operating the water treatment system shown in Fig. 9.

[0054] When the chemical passing process is completed (step S41), valves 530, 540, 570, and 580 are controlled to open and close so that cleaning water from cleaning water tank 700 is supplied to degassing device 200 and the cleaning water passed through degassing device 200 is supplied to water treatment device 300 (step S42). Specifically, control device 603 controls the opening and closing of valve 570 so that the chemical from chemical tank 400 is not supplied to valve 580 and so that cleaning water from cleaning water tank 700 is supplied to degassing device 200 via valve 580. Control device 603 also controls the opening and closing of valve 580 so that liquid from raw water tank 100 is not supplied to degassing device 200 and so that cleaning water from valve 570 is supplied to degassing device 200. Furthermore, the control device 603 controls the opening and closing of the valve 530 so that the chemical liquid from the chemical liquid tank 400 is not supplied to the water treatment device 300 and so that the cleaning water from the degassing device 200 is supplied to the water treatment device 300. Furthermore, the control device 603 controls the opening and closing of the valve 540 so that the cleaning water from the water treatment device 300 flows into a waste path.

[0055] In addition, the liquid medicine passage path for the drug passage process in this embodiment has been described as being the same as that in the second embodiment, but this is not limited to this. For example, the liquid medicine passage path in the first embodiment or the liquid medicine passage path in the third embodiment may also be used.

[0056] In this manner, in the present embodiment, in the cleaning process that is performed after the process of passing a chemical solution through the degassing device and water treatment device that constitute the water treatment system to regenerate them, cleaning water is supplied to the degassing device, and the cleaning water that has passed through the degassing device is supplied to the water treatment device, thereby reducing the amount of cleaning water used in the cleaning process and the amount of cleaning water discharged.

[0057] In addition, the water treatment device 300 may be located upstream of the degassing device 200 during the water flow process. In a cleaning process using this configuration, the water treatment device 300 may be cleaned and then the cleaning water discharged from the water treatment device 300 may be supplied to the degassing device 200 to clean the degassing device 200. Furthermore, separate processes may be performed on the degassing device 200 and the water treatment device 300 before or after the water flow process, chemical flow process, and cleaning process. For example, a flushing process using raw water to replace the liquid inside the degassing device or water treatment device, a process of circulating a chemical solution through the degassing membrane or separation membrane, a pushing process supplying water to the ion exchange resin to push out the chemical solution, a circulation standby process in which water is circulated within the device in preparation for water collection, and a soaking process may be performed. Regardless of which process is performed, the present invention contributes to reducing the downtime of the entire system, reducing the amount of chemicals used in the chemical water flow process, and reducing water consumption. Furthermore, the direction of raw water flow and the direction of chemical flow through the degassing device 200 and the water treatment device 300 are not particularly limited. For example, in Fig. 2, the direction in which raw water and the chemical solution are passed through the degassing device 200 and the water treatment device 300 is shown as being from bottom to top, but they may be from top to bottom. Furthermore, the direction in which raw water is passed and the direction in which the chemical solution is passed may be opposite directions. These directions may be externally settable.

[0058] [Example 1] Water flow process: The raw water was pretreated to remove turbidity and chlorine, and then treated with a degassing membrane and an anion exchange resin device to obtain treated water. A 3M separation membrane module was used as the degassing membrane. The water treatment device used was an anion exchanger filled with anion exchange resins AMBERJET 4200 (manufactured by DuPont) and IRA 96RF (manufactured by DuPont) in a 2:1 ratio. Medication process: Sodium hydroxide was added to the treated water obtained in the water passing process, and a 1.5% sodium hydroxide solution was prepared as a cleaning solution. The cleaning solution was passed through the degassing membrane and the anion exchange resin device, respectively, and regeneration was carried out. After regeneration was carried out for a predetermined time, the raw water was passed through the anion exchange resin device to wash the anion exchange resin. Thereafter, the raw water was passed through the degassing membrane to wash the degassing membrane. After the cleaning of the degassing membrane and the anion exchange resin device was completed, the process moved on to the water passing process. [Example 2] In the washing step, the raw water was passed through an anion exchange resin, and the degassing membrane was washed with the water that had passed through the anion exchange resin. [Comparative Example] The degassing membrane and the anion exchange resin were regenerated and washed separately.

[0059] FIG. 11 is a table showing the results of Examples 1 and 2 and the Comparative Example. As shown in FIG. 11, in the Comparative Example, the degassing membrane and the anion exchange resin device were regenerated and cleaned separately, which took a long time due to the separate treatments. On the other hand, in Example 1, the degassing membrane and the anion exchange resin were regenerated simultaneously, which shortened the time for the chemical passage process. Furthermore, in Example 2, the water used to wash the anion exchange resin was passed through the degassing membrane (reused), thereby shortening the cleaning time and reducing the amount of cleaning water used.

[0060] Although the above description has been given with each component assigned a respective function (process), this allocation is not limited to the above. Furthermore, the configuration of the components is also not limited to the above, and the above-described embodiments are merely examples. Furthermore, the above-described valves 510, 520, 530, 540, 550, 560, 570, and 580 are not limited to three-way valves, and may be a combination of independent valves that open and close their respective inputs and outputs. [Explanation of symbols]

[0061] 100 raw water tank 200 Degassing device 300 Water Treatment Equipment 400 Chemical Tank 510,520,530,540,550,560,570,580 Valves 600~603 Control device 700 cleaning water tank

Claims

1. A water treatment system including a membrane separation device and an ion exchange device, a first pipe for simultaneously supplying a chemical solution to the membrane separation device and the ion exchange device in parallel; a first valve group provided in the first pipe; a control device that controls the opening and closing of the first valve group.

2. 2. The water treatment system according to claim 1, The control device controls the opening and closing of the first valve group so that chemical solution is supplied to the membrane separation device and the ion exchange device when the difference between the pressure upstream of the membrane separation device and the pressure downstream of the membrane separation device exceeds a predetermined threshold.

3. The water treatment system according to claim 1 or 2, a second pipe for supplying the chemical solution passed through the membrane separation device to the ion exchange device; a second valve group provided in the second pipe, The control device controls opening and closing of the second valve group so that the chemical solution passed through the membrane separation device is supplied to the ion exchange device.

4. 4. The water treatment system according to claim 3, The control device controls the opening and closing of the second valve group based on at least one of the TOC value, pH value, and conductivity of the chemical solution passed through the membrane separation device so that the chemical solution passed through the membrane separation device is supplied to the ion exchange device.

5. The water treatment system according to claim 1 or 2, a third pipe for supplying the chemical solution passed through the ion exchange device to the membrane separation device; a third valve group provided in the third pipe, The control device controls opening and closing of the third valve group so that the chemical solution passed through the ion exchange device is supplied to the membrane separation device.

6. The water treatment system according to claim 1 or 2, The water treatment system, wherein the ion exchange device is filled with an anion exchange resin, and the chemical solution is an alkaline liquid.

7. The water treatment system according to claim 1 or 2, The water treatment system, wherein the ion exchange device is filled with a cation exchange resin, and the chemical solution is an acidic liquid.

8. The water treatment system according to claim 1 or 2, a fourth pipe for supplying wash water to the membrane separation device and the ion exchange device; a fourth valve group provided in the fourth pipe, The control device controls the opening and closing of the fourth valve group so that the cleaning water is supplied to the membrane separation device and the ion exchange device after the chemical solution has been passed through the membrane separation device and the ion exchange device.

9. A water treatment system including a membrane separation device and an ion exchange device, a first pipe for supplying a chemical solution to the membrane separation device; a second pipe for supplying the chemical solution passed through the membrane separation device to the ion exchange device; a first valve group provided in the first pipe; a second valve group provided in the second pipe; a control device that controls opening and closing of the first valve group and the second valve group, The control device controls opening and closing of the second valve group so that the chemical solution passed through the membrane separation device is supplied to the ion exchange device.

10. A method for operating a water treatment system including a membrane separation device and an ion exchange device, comprising: a water passing step of passing the water to be treated through the membrane separation device and the ion exchange device by controlling the opening and closing of valves arranged in piping; A method for operating a water treatment system, comprising: controlling the opening and closing of the valve based on predetermined timing; and carrying out a chemical supplying step of simultaneously supplying chemicals to the membrane separation device and the ion exchange device in parallel.

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