Water treatment management device and water quality monitoring method

Abstract

To make it possible to accurately measure a total organic carbon (TOC) concentration without being influenced by an inorganic carbon (IC) component contained in water of a monitoring target, in a water treatment control device monitoring and evaluating water supplied to a water treatment system for an operation control of the water treatment system.SOLUTION: A water treatment control device (20) is provided with equipment (31, 33, 34, 36) that performs treatment on the target water to which water to be supplied to the water treatment control system is supplied, an evaluation pure water production section (21) that executes unit operations for removing a TOC component, measurement means (22) that measures the TOC concentration of water to be measured obtained from measurement points in the evaluation pure water production section (21), and inorganic carbon removing means (32, 35, 37) for removing the inorganic carbon contained in the water to be measured that is supplied to the measuring means (22). An inorganic carbon concentration of the water to be measured supplied to the measuring means (22) is 10 times or less by weight the TOC concentration measured value by the measuring means (22).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water treatment management device and a water quality monitoring method used when performing water treatment such as ultrapure water production using a water treatment system. [Background technology]

[0002] For example, in water treatment systems such as ultrapure water production systems that produce ultrapure water from raw water, it is necessary to pay attention to the quality of the raw water supplied to the water treatment system. For example, ultrapure water production systems use reverse osmosis (RO) membrane treatment and ultraviolet (UV) oxidation treatment to remove organic substances (TOC (Total Organic Carbon) components) contained in the raw water. However, among organic components, there are components that are easy to remove by these treatments and components that are not.

[0003] Traditionally, tap water, municipal water, and industrial water have been used as raw water for ultrapure water production systems. In recent years, in order to efficiently utilize water resources, reclaimed water and recycled water, which are produced by first treating industrial wastewater and other sources, have begun to be used as raw water. Unlike industrial water, the quality of reclaimed and recycled water may be unstable, and they may suddenly contain unexpected organic matter. If organic matter that is difficult to remove is mixed into the raw water, it may affect the quality of the treated water at the output of the ultrapure water production system. In particular, for ultrapure water production systems with high treatment capacities, it takes time for changes in the quality of the raw water supplied to the system to reach the output. Therefore, it is not appropriate to detect changes in the quality of the treated water obtained at the output and then respond to the changes in the raw water quality. It is becoming increasingly important to monitor the quality of the raw water in ultrapure water production systems and appropriately manage the operation of the ultrapure water production system according to the water quality.

[0004] In order to monitor the quality of raw water and appropriately manage the operation of water treatment systems such as ultrapure water production systems, it has been proposed to use a device installed separately from the water treatment system. Here, these devices installed separately from the water treatment system are collectively referred to as a water treatment management device. A water treatment management device consists of equipment that performs the unit operations required to remove TOC (total organic carbon) components and a measuring means for measuring the TOC concentration. If the TOC concentration of treated water remains high after treatment to remove TOC components in the water treatment management device, it can be concluded that the raw water contains organic species that are difficult to remove using typical TOC removal operations.

[0005] Patent Document 1 discloses a method for monitoring and evaluating the quality of raw water supplied to a water treatment system using a water treatment management device having a pure water production unit for evaluation, which is configured by combining devices that perform unit operations required to remove TOC components, and a measuring means for measuring TOC concentrations at multiple measurement points in the pure water production unit for evaluation. The pure water production unit for evaluation is a pure water production system that is not equivalent to the water treatment system, and is equipped with devices such as a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchange device to remove TOC components. The water treatment management device of Patent Document 1 has a problem in that if a cartridge polisher, a non-regenerative mixed-bed ion exchange device, is used as the ion exchange device in the pure water production unit for evaluation, the ion exchange device must be replaced frequently when the concentration of ionic impurities in the raw water is high.

[0006] Patent Document 2 uses a sub-ultrapure water production system configured equivalent to a main ultrapure water production system, and detects the TOC concentration of the outlet water from the sub-ultrapure water production system to determine the quality of the raw water and manage the operation of the main ultrapure water production system. Because the sub-ultrapure water production system is equivalent to the main ultrapure water production system, if the main ultrapure water production system is equipped with a pretreatment device, such as an ion exchange device, upstream of a reverse osmosis membrane device, the sub-ultrapure water production system must also be equipped with a similar pretreatment device. This increases the size of the sub-ultrapure water production system and may limit the installation space for the sub-ultrapure water production system. Furthermore, if a pretreatment device is installed, maintenance processes required for the pretreatment device, such as a regeneration process for a regenerative ion exchange device, must be performed, which complicates the operation of the sub-ultrapure water production system and increases operating costs.

[0007] Patent Document 3 discloses a monitoring device that has an ultraviolet irradiation device and a deionization device installed downstream of the ultraviolet irradiation device, and that measures the TOC concentration in raw water supplied to the ultraviolet irradiation device and in the outlet water of the deionization device. In the ultraviolet oxidation treatment performed by the ultraviolet irradiation device, the efficiency of TOC decomposition and removal decreases if the water to be treated contains ions or impurities. However, the monitoring device described in Patent Document 3 does not have a device for removing ions and impurities installed upstream of the ultraviolet irradiation device, and depending on the quality of the raw water, the original TOC decomposition and removal performance of the ultraviolet irradiation device may not be fully achieved, making it impossible to properly evaluate the quality of the raw water. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2019-155275 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-107249 [Patent Document 3] Japanese Patent Application Publication No. 2020-159961 Summary of the Invention [Problem to be solved by the invention]

[0009] In order to monitor the quality of raw water supplied to a water treatment system and appropriately manage the operation of the water treatment system, a water treatment management device installed separately from the water treatment system is equipped with a means for measuring the TOC concentration in water, as described in Patent Documents 1 to 3 mentioned above. TOC measurement devices for measuring the TOC concentration in sample water typically oxidize the TOC components in the sample water to carbon dioxide (carbon dioxide) using some method, measure the concentration of the generated carbon dioxide using some method, and convert it into a TOC concentration. In recent years, measurement devices have been widely used that decompose the TOC components in the sample water using ultraviolet oxidation, quantify the amount of carbon dioxide generated by the TOC decomposition, and convert it into a TOC concentration. In this case, a commonly used method for quantifying the amount of carbon dioxide is to measure the conductivity of the sample water and the conductivity of the sample water after ultraviolet oxidation, and convert the difference in conductivity into a carbon dioxide concentration. However, with this method, if the sample water contains ions other than carbon dioxide that exhibit conductivity, these ions will affect the TOC concentration measurement. A TOC concentration measurement method that is not affected by the concentration of ions in the sample water involves measuring conductivity using a gas-permeable membrane. The gas-permeable membrane method In this method, carbon dioxide is generated by ultraviolet oxidation, and only the carbon dioxide is separated using a gas-permeable membrane and dissolved in deionized water. The conductivity of the deionized water with dissolved carbon dioxide is measured and converted into TOC concentration. The method using a gas-permeable membrane allows the TOC concentration of sample water to be measured without being affected by other ions.

[0010] The TOC concentration measurement method in sample water involves oxidizing TOC components in the sample water to generate carbon dioxide. Therefore, the amount of carbon dioxide actually measured includes that derived from inorganic carbon (IC). The inorganic carbon components in sample water or raw water are generally thought to be carbon dioxide, carbonate ions, bicarbonate ions, or their salts. In practical TOC concentration measurement devices, the total carbon (TC) concentration is calculated from the amount of carbon dioxide measured after UV oxidation. The inorganic carbon concentration is then calculated separately from the sample water before UV oxidation. The TOC concentration is then calculated by subtracting the inorganic carbon concentration from the total carbon concentration. When measuring trace TOC concentrations, e.g., on the order of μg / L, using such TOC measurement devices, the accuracy of the TOC measurement deteriorates if the sample water contains high levels of carbon dioxide. While some methods combine the device with a carbon dioxide removal device, the TOC components eluting from the carbon dioxide removal device may affect the TOC measurement value. None of the techniques described in Patent Documents 1 to 3 above take into consideration the influence of inorganic carbon components during TOC measurement, which can make it difficult to measure TOC concentration and manage water treatment systems based on TOC concentration.

[0011] An object of the present invention is to provide a water treatment management device and a water quality monitoring method that monitor and evaluate water supplied to a water treatment system for the purpose of managing the operation of the water treatment system, and that can accurately measure the total organic carbon (TOC) concentration without being affected by inorganic carbon (IC) components contained in the water being monitored. [Means for solving the problem]

[0012] The water treatment management device of the present invention is a water treatment management device used for managing the operation of a water treatment system, which is supplied with water to be supplied to a water treatment system as target water and performs treatment on the target water, and is equipped with an evaluation pure water production unit that performs unit operations to remove TOC components, and a measurement means for measuring the TOC concentration of the target water.The water treatment management device is characterized in that the evaluation pure water production unit is provided with inorganic carbon removal means that removes inorganic carbon contained in the target water, and the evaluation pure water production unit is equipped with at least a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchanger filling device filled with an ion exchanger containing at least an anion exchanger as equipment, and the target water is treated by passing it through the reverse osmosis membrane device, the ultraviolet irradiation device, and the ion exchanger filling device in that order, and the target water is at least one of the target water and treated water of at least one device, and the inorganic carbon removal means removes inorganic carbon contained in the target water, either alone or in cooperation with the reverse osmosis membrane device, and the inorganic carbon concentration of the target water supplied to the measurement means is 10 times or less by weight of the TOC concentration measured by the measurement means.

[0013] The water quality monitoring method of the present invention is a water quality monitoring method for monitoring the water quality of target water, with water to be supplied to a water treatment system as the target water, and includes the steps of: supplying the target water to an evaluation pure water production section that is provided separately from the water treatment system and performs unit operations for removing TOC components; measuring the TOC concentration of the target water at one or more measurement points in the evaluation pure water production section, which may include an inlet and outlet of the evaluation pure water production section, using a measurement means; and removing inorganic carbon so that the inorganic carbon concentration of the target water supplied to the measurement means is 10 times or less by weight of the TOC concentration measured by the measurement means. [Effects of the Invention]

[0014] According to the present invention, in a water treatment management device and a water quality monitoring method that monitor and evaluate water supplied to a water treatment system for the purpose of operational management of the water treatment system, it is possible to accurately measure the TOC concentration without being affected by inorganic carbon components contained in the water being monitored. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing a configuration of a water treatment management apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a water treatment management apparatus according to a second embodiment. [Figure 3] FIG. 10 is a diagram illustrating a configuration of a water treatment management apparatus according to a third embodiment. [Figure 4] FIG. 10 is a diagram illustrating a configuration of a water treatment management apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, embodiments of the present invention will be described with reference to the drawings.

[0017] [First embodiment] FIG. 1 shows a water treatment management system according to a first embodiment of the present invention. Given a water treatment system 10, such as an ultrapure water production system, a water treatment management system 20 according to the present invention is used for operational management of the water treatment system 10. It is connected to a pipe for raw water to be supplied to the water treatment system 10 and monitors and evaluates the quality of the raw water. While the raw water may be, for example, industrial water or recycled water, in the following description, the water to be supplied to the water treatment system 10 will be broadly referred to as raw water. The water treatment system 10 may be configured to switch between different supply sources and supply raw water. In the illustrated example, two systems of raw water can be switched (or mixed) and supplied to the water treatment system 10. To this end, valves 11 and 12 are provided on the two systems of raw water pipes, respectively. These pipes merge at the outlets of the valves 11 and 12, and an additional valve 15 is provided between the junction C and the water treatment system 10. A pipe 16 for supplying raw water to the water treatment management system 20 branches off between the junction C and the valve 15. Valve 15 is provided to enable monitoring and evaluation of the quality of raw water even when the supply of raw water to water treatment system 10 is cut off. For example, water treatment management device 20 confirms the presence of persistent TOC components in the raw water, which is the target water, and monitors their concentrations, and by controlling the opening and closing of valves 11, 12, and 15 based on the obtained results, it is possible to control the flow rate of raw water from which source to supply to water treatment system 10. Here, persistent TOC components refer to TOC components that are difficult to remove by reverse osmosis membrane treatment or ultraviolet oxidation treatment, and in particular, TOC components that are difficult to decompose and remove by general ultraviolet oxidation treatment.

[0018] The water treatment management system 20 broadly comprises a test pure water production unit 21 and a TOC (total organic carbon) measurement device 22. The test pure water production unit 21 is an apparatus that produces pure water from target water supplied via piping 16 and is composed of a combination of multiple types of equipment that treat the target water. These equipment include one that performs a unit operation for removing TOC components. The test pure water production unit 21 of the water treatment management system 20 according to the present invention is equipped with at least the following equipment for treating the target water: a reverse osmosis membrane device (RO) 31; an ultraviolet irradiation device (UV) 33 that receives the water treated by the reverse osmosis membrane device 31 and performs ultraviolet oxidation treatment; and a deionization device filled with ion exchangers and to which outlet water from the ultraviolet irradiation device 33 is supplied. The ion exchangers filled in the deionization device include at least anion exchangers. In the water treatment management system 20 of the first embodiment, the deionization device is a cartridge polisher (CP) 34 filled with a mixed bed of anion exchange resin and cation exchange resin.

[0019] The TOC measurement device 22 measures the TOC concentration of water at one or more measurement points within the evaluation pure water production unit 21. The measurement points may include the inlet and outlet of the evaluation pure water production unit 21. In this case, the TOC measurement device 22 measures the TOC concentration of the target water itself supplied to the evaluation pure water production unit 21 and the TOC concentration of the outlet water of the evaluation pure water production unit 21. A commercially available online TOC measurement device, TOC concentration meter, TOC meter, or the like can be used as the TOC measurement device 22. When managing the operation of the water treatment system 10, which is an ultrapure water production system, it is preferable to use the TOC measurement device 22 to measure at least one of the TOC concentration of the outlet water of the evaluation pure water production unit 21 (the treated water from the cartridge polisher 34 in the example shown in FIG. 1 ) and the TOC concentration of water treated by the reverse osmosis membrane device 31 but before treatment by the ultraviolet irradiation device 33. Incidentally, it has been found that when the TOC concentration in the water to be measured is low, for example, on the order of μg / L, and the IC (inorganic carbon) concentration contained therein is high, the accuracy of the TOC concentration measured by the TOC measuring device 22 decreases. The inventors have found that if the IC concentration of the water to be measured is 10 times or less by weight of the TOC concentration value obtained when that water is measured by the TOC measuring device 22, the error in the TOC concentration measurement by the TOC measuring device 22 is reduced, and operation and management of the water treatment system 10 can be performed stably. The IC concentration of the water to be measured is preferably 6 times or less by weight, and more preferably 3 times or less by weight, of the TOC concentration measured by the TOC measuring device 22.

[0020] In the water treatment management system 20 of the first embodiment, the pure water production unit 21 for evaluation includes at least a reverse osmosis membrane device 31 equipped with a reverse osmosis membrane and supplied with target water via a pipe 16; an electrodeionized water production unit (hereinafter also referred to as an EDI device) 32 connected to the outlet of the reverse osmosis membrane device 31 and supplied with permeated water from the reverse osmosis membrane; an ultraviolet irradiation device 33 connected to the outlet of the EDI device 32 and performing ultraviolet oxidation treatment on the treated water from the EDI device 32; and a deionization device filled with ion exchangers and supplied with treated water from the ultraviolet irradiation device 33. The ion exchangers filled in the deionization device include at least anion exchangers. In the water treatment management system 20 shown in FIG. 1, the deionization device is a cartridge polisher (CP) 34 filled with a mixed bed of anion exchange resin and cation exchange resin. A portion of the treated water from the EDI device 32 branches off and is supplied to the TOC measurement device 22 via a valve 52. A portion of the outlet water from the pure water production unit 21 for evaluation branches off and is supplied to the TOC measurement device 22 via a valve 54. By controlling the opening and closing of valves 52 and 54, the TOC measuring device 22 can alternately measure the TOC concentration of the treated water from the EDI device 32 and the TOC concentration of the outlet water from the evaluation pure water producing unit 21. The remaining portion of the outlet water from the evaluation pure water producing unit 21 is recovered or discharged. Since the reverse osmosis membrane device 31 in the evaluation pure water producing unit 21 is provided to remove TOC components, in the following description, of the two types of water discharged from the reverse osmosis membrane device 31, i.e., the water that has permeated the reverse osmosis membrane and the concentrated water, the water that has permeated the reverse osmosis membrane will be referred to as the treated water from the reverse osmosis membrane device 31.

[0021] In the water treatment management system 20 shown in Figure 1, the EDI device 32 is provided to remove inorganic carbon components contained in the treated water from the reverse osmosis membrane device 31. The EDI device 32 is equipped with a deionization compartment filled with an ion exchanger and produces deionized water by combining electrophoresis and electrodialysis. Water to be treated is supplied to the deionization compartment, and the deionization (demineralization) process of the water using the ion exchanger and the regeneration process of the ion exchanger are simultaneously performed. The water demineralized in the deionization compartment is discharged from the deionization compartment as treated water from the EDI device 32. Therefore, the EDI device 32 falls under the category of an ion exchanger-filled device.

[0022] While the EDI device 32 can efficiently remove inorganic carbon components, such as carbonate, it does not remove nonionic TOC components, or only to a limited extent. Therefore, the TOC concentration of the treated water from the EDI device 32 can be treated as the TOC concentration of the treated water from the reverse osmosis membrane device 31. Moreover, because the EDI device 32 removes inorganic carbon components, measuring the TOC concentration of the treated water from the EDI device 32 enables stable and more accurate measurement of the TOC concentration of the treated water from the reverse osmosis membrane device 31. While it is possible to remove inorganic carbon components using an ion exchanger-filled device, such as a general ion exchange resin tower simply filled with ion exchange resin, if the ionic load of the treated water is high, inorganic carbon components will leak out within a short period of time, necessitating frequent regeneration or replacement of the ion exchanger. On the other hand, the EDI device 32 is a continuous regeneration type device, and desalination and ion exchanger regeneration proceed simultaneously in the desalination compartment, eliminating the need for regeneration processes required for general ion exchange resin towers. By using the EDI device 32, it becomes possible to stably remove inorganic carbon components over a long period of time even when the inorganic carbon load is relatively high.

[0023] The installation location of the EDI device 32, which is used to remove inorganic carbon components that can cause errors in TOC concentration measurement, is not particularly limited, but is preferably located downstream of the reverse osmosis membrane device 31 and upstream of the ultraviolet irradiation device 33, as shown in FIG. 1. In the water treatment management system 20 shown in FIG. 1, the reverse osmosis membrane device 31 and the EDI device 32 can highly effectively remove ionic components from the water to be treated. This improves the TOC decomposition efficiency in the ultraviolet irradiation device 33 and reduces the ionic load on an ion exchanger filling device, such as a cartridge polisher 34, located downstream of the ultraviolet irradiation device 33, thereby eliminating the need for frequent regeneration or replacement of the ion exchanger filling device. In the first embodiment, an additional EDI device may be provided instead of the cartridge polisher 34.

[0024] [Second embodiment] Since the inorganic carbon components in the target water supplied to the water treatment management system 20 are usually carbonate components, a degassing device can be used to remove the inorganic carbon. Examples of the degassing device include a decarbonation membrane device. While there are no particular limitations on the location of the degassing device, it is preferable to install it upstream of the reverse osmosis membrane device 31. The degassing device may also be installed between the reverse osmosis membrane device 31 and the ultraviolet irradiation device 33. When a degassing device is installed, the EDI device 32 does not need to be installed downstream of the reverse osmosis membrane device 31 and upstream of the ultraviolet irradiation device 33. When a degassing device is installed upstream of the reverse osmosis membrane device 31, the water treatment management system preferably measures at least one of the TOC concentrations of the treated water from the degassing device, the treated water from the reverse osmosis membrane device 32, and the outlet water from the pure water production unit 21 for evaluation. To efficiently remove inorganic carbon in the form of carbonate and bicarbonate using the degassing device, a pH adjustment means can be installed upstream of the degassing device to adjust the pH of the water supplied to the degassing device to be more acidic.

[0025] 2 shows a water treatment control system 20 according to a second embodiment of the present invention, which includes a degassing device. The water treatment control system 20 shown in FIG. 2 is the same as the water treatment control system 20 shown in FIG. 1 except that the EDI device 32 has been removed and replaced with a membrane degassing device 35 upstream of the reverse osmosis membrane device 31, and an EDI device 36 has been installed instead of the cartridge polisher 34. Therefore, in the evaluation pure water production section 21 of the water treatment control system 20 shown in FIG. 2, the target water is supplied from the piping 16 to the reverse osmosis membrane device 31 via the membrane degassing device 35, the treated water from the reverse osmosis membrane device 31 is supplied directly to the ultraviolet irradiation device 33, the treated water from the ultraviolet irradiation device 33 is supplied to the EDI device 36, and the treated water from the EDI device 36 is the outlet water of the evaluation pure water production section 21. A portion of the treated water from the membrane degassing device 35 branches off and is supplied to the TOC measuring device 22 via valve 55, a portion of the treated water from the reverse osmosis membrane device 31 branches off and is supplied to the TOC measuring device 22 via valve 51, and a portion of the outlet water from the evaluation pure water producing unit 21 branches off and is supplied to the TOC measuring device 22 via valve 56. By controlling the opening and closing of valves 51, 55, and 56, the TOC measuring device 22 can switch between measuring the TOC concentration of the treated water from the membrane degassing device 35, the TOC concentration of the treated water from the reverse osmosis membrane device 31, and the TOC concentration of the outlet water from the evaluation pure water producing unit 21. Furthermore, the water treatment management system 20 shown in FIG. 2 uses an EDI device 36 instead of a cartridge polisher 34, which enables stable removal of TOC components even when the ion load is high.

[0026] [Third embodiment] Figure 3 shows a water treatment management system 20 according to a third embodiment of the present invention. The water treatment management system 20 shown in Figure 3 is equipped with a degassing device similar to that shown in Figure 2. Specifically, a membrane degassing device 35 is provided upstream of the reverse osmosis membrane device 31 in the water treatment management system 20 shown in Figure 1, and the test pure water production section 21 supplies the target water to the reverse osmosis membrane device 31 via the membrane degassing device 35. When the membrane degassing device 35 is provided in this manner, it is preferable to measure the TOC concentration of any one of the treated water from the membrane degassing device 35, the treated water from the reverse osmosis membrane device 31, the treated water from the EDI device 32, and the treated water from the cartridge polisher 34. In the system shown in FIG. 3, a portion of the treated water from the membrane degassing device 35 branches off and is supplied to the TOC measuring device 22 via valve 55. A portion of the treated water from the reverse osmosis membrane device 31 branches off and is supplied to the TOC measuring device 22 via valve 51. A portion of the treated water from the EDI device 32 branches off and is supplied to the TOC measuring device 22 via valve 52. A portion of the outlet water from the evaluation pure water production unit 21 branches off and is supplied to the TOC measuring device 22 via valve 54. By controlling the opening and closing of valves 51, 52, 54, and 55, the TOC measuring device 22 can selectively measure the TOC concentration of the treated water from the membrane degassing device 35, the TOC concentration of the treated water from the reverse osmosis membrane device 31, the TOC concentration of the treated water from the EDI device 32, and the TOC concentration of the outlet water from the evaluation pure water production unit 21. The water treatment management system 20 shown in FIG. 3 may also include a pH adjustment means upstream of the membrane degassing device 35. In this case, it is preferable to adjust the pH of the water supplied to the membrane degassing device 35 to be more acidic.

[0027] [Fourth embodiment] In the second and third embodiments described above, a pH adjusting means can be provided upstream of the degassing device, but by providing a pH adjusting means upstream of the reverse osmosis membrane device and supplying water whose pH has been adjusted by the pH adjusting means to the reverse osmosis membrane device, it is possible to promote the removal of inorganic carbon. The pH adjusting means works in conjunction with the reverse osmosis membrane device to remove inorganic carbon contained in the water to be measured. In this case, it is preferable to adjust the pH of the water supplied to the reverse osmosis membrane device to the alkaline side. Inorganic carbon contained in water is mainly carbon dioxide (CO2), carbonate ions (CO3 2- ) and bicarbonate ion (HCO3- ), and their relative abundance varies depending on the pH. On the alkaline side, the proportion of carbonate ions, which are polyvalent ions, increases, making them more easily removed by the reverse osmosis membrane. When a pH adjustment means is provided upstream of the reverse osmosis membrane device, it is preferable to connect an ultraviolet irradiation device and an EDI device in this order downstream of the reverse osmosis membrane device. In this connection, it is preferable to measure at least one of the TOC concentration of the treated water from the reverse osmosis membrane device and the TOC concentration of the treated water from the EDI device. Alternatively, it is also possible to connect an EDI device, an ultraviolet irradiation device, and a cartridge polisher in this order downstream of the reverse osmosis membrane device. In this connection, it is preferable to measure at least one of the TOC concentration of the treated water from the reverse osmosis membrane device, the TOC concentration of the treated water from the EDI device, and the TOC concentration of the treated water from the cartridge polisher.

[0028] FIG. 4 shows a water treatment management system 20 according to a fourth embodiment of the present invention. The water treatment management system 20 shown in FIG. 4 differs from the water treatment management system 20 shown in FIG. 2 in that, instead of providing the membrane degassing device 35, a pH adjustment device 37 serving as a pH adjustment means is provided upstream of the reverse osmosis membrane device 31, allowing the pH of the target water supplied to the reverse osmosis membrane device 31 to be adjusted by the pH adjustment device 37. A portion of the treated water from the reverse osmosis membrane device 31 is supplied to the TOC measurement device 22 via a valve 51, and a portion of the treated water from the EDI device 36 is supplied via a valve 56. By controlling the opening and closing of the valves 51 and 56, the TOC measurement device 22 can selectively measure the TOC concentration of the treated water from the reverse osmosis membrane device 31 and the TOC concentration of the outlet water from the evaluation pure water production unit 21.

[0029] An example of a water treatment management apparatus 20 according to the present invention has been described above. Once the TOC concentration is obtained in the water treatment management apparatus 20, the operating conditions of the reverse osmosis membrane device and the ultraviolet irradiation device included in the water treatment system 10 (e.g., the recovery rate in the reverse osmosis membrane device and the ultraviolet irradiation dose in the ultraviolet irradiation device) may be controlled based on the TOC concentration. A control mechanism for controlling the operating conditions of the water treatment system 10 may be provided within the water treatment management apparatus 20. If the water treatment system 10 can be supplied with raw water from multiple sources, the raw water actually supplied to the water treatment system 10 may be switched based on the TOC concentration measured by the water treatment management apparatus 20, as described in Patent Document 1. Furthermore, instead of the raw water supplied to the inlet of the water treatment system 10, water flowing through the water treatment system 10 during the process of producing ultrapure water from the raw water may be branched and supplied to the water treatment management apparatus 20 as target water. For example, if a filter, activated carbon device, primary pure water system, etc. is installed on the inlet side of the water treatment system 10, the outlet water of the filter, activated carbon device, or primary pure water system may be supplied to the water treatment management device 20 to manage the operation of the water treatment system 10.

[0030] In the water treatment management system 20 according to the present invention, it is preferable to provide an oxidant removal means upstream of the reverse osmosis membrane device 31 to prevent deterioration of the reverse osmosis membrane by oxidants. In the present invention, the inorganic carbon (IC) concentration in the water to be measured is set to 10 times or less by weight of the TOC concentration obtained by the TOC measurement device, and the operating conditions of each device constituting the water treatment management system 20 may be controlled to satisfy this condition. For example, the current value and water flow rate value (SV value) of the EDI device, and the recovery rate of the reverse osmosis membrane device may be controlled. [Example]

[0031] Next, the present invention will be described in more detail with reference to examples and comparative examples.

[0032] [Example 1 and Comparative Example 1] Water containing dissolved carbon dioxide as an inorganic carbon (IC) component and isopropyl alcohol as a TOC component was prepared as a sample water. The only TOC component in the sample water was isopropyl alcohol. The exact TOC concentration of the sample water was determined by quantifying the isopropyl alcohol content in the sample water using GC-MS (gas chromatography-mass spectrometry). The TOC concentration of the sample water was then adjusted to 10 μg / L and 100 μg / L. The TOC concentration of the sample water was measured using a TOC analyzer while varying the amount of added carbon dioxide to change the inorganic carbon concentration. The TOC measurement accuracy of the TOC analyzer was determined. A Sievers M500e TOC analyzer manufactured by SUEZ was used. This TOC analyzer can simultaneously measure the inorganic carbon (IC) concentration in the sample water, and thus the inorganic carbon concentration was determined simultaneously with the TOC concentration. The results are shown in Table 1. In Table 1, the "IC / TOC weight ratio" is the ratio of the inorganic carbon concentration to the TOC concentration based on the mass of carbon contained in the sample water. Furthermore, "measurement accuracy" represents the TOC concentration value obtained by the TOC meter, with the TOC concentration value based on GC-MS measurement taken as 100%.

[0033] [Table 1]

[0034] In Examples 1-1 to 1-12, where the IC / TOC weight ratio was 10 or less, the measurement accuracy was 70% or more, and it was found that the TOC concentration could be measured within an accuracy range of 30%. In particular, in Examples 1-1 to 1-4 and 1-7 to 1-10, where the IC / TOC weight ratio was 3 or less, the measurement accuracy was 90% or more, and the TOC concentration could be measured within an accuracy range of 10%. In contrast, in Comparative Examples 1-1 to 1-4, where the IC / TOC weight ratio was more than 10, the measurement accuracy was less than 70%. The measurement accuracy significantly deteriorated as the IC / TOC weight ratio increased.

[0035] [Example 2] The water treatment management apparatus 20 of the first embodiment shown in FIG. 1 was assembled as the water treatment management apparatus of Example 2. Sample water was passed through this water treatment management apparatus, and the TOC concentrations of the water treated by the EDI device 32 (EDI-treated water) and the water treated by the cartridge polisher 34 (CP-treated water) were measured using a TOC meter, which is the TOC measurement device 22. The sample water was prepared by adding isopropyl alcohol to a TOC concentration of 1000 μg / L, dissolving carbon dioxide to an inorganic carbon concentration of 10 mg / L, and adjusting the pH to 7. The inorganic carbon concentration in the sample water was 10 times the TOC concentration by weight. The isopropyl alcohol concentrations of the water treated by the reverse osmosis membrane device 31 (RO-treated water), the EDI-treated water, and the CP-treated water were each measured using GC-MS and converted to TOC concentrations. Based on the TOC meter measurement results and the GC-MS measurement results, the TOC concentration measurement accuracy of the TOC meter was determined in the same manner as in Example 1. The results are shown in Table 2.

[0036] In Example 2, the same TOC meter as used in Example 1 was used. ESPA2 manufactured by Nitto Denko Corporation was used as the reverse osmosis membrane constituting the reverse osmosis membrane device 31, and the reverse osmosis membrane device 31 was operated at a recovery rate of 50%. The EDI device 32 used had a deionization compartment divided into a first small deionization compartment on the anode side and a second small deionization compartment on the cathode side, with an intermediate ion exchange membrane sandwiched between them. The first small deionization compartment was filled with a cation exchange resin (CER), and the second small deionization compartment was filled with an anion exchange resin (AER). The concentration compartment and cathode compartment were filled with anion exchange resin, and the anode compartment was filled with cation exchange resin. The current value in the EDI device 32 was 0.6 A (current density 0.5 A / dm 2 As the ultraviolet irradiation device 33, a low-pressure ultraviolet oxidation device manufactured by Nippon Photo Science Co., Ltd. was used, and the irradiation amount was 0.4 kWh / m 3 It was decided.

[0037] Comparative Example 2 The EDI device 32 was removed from the water treatment management system of Example 2, and a water treatment management system for Comparative Example 2 was assembled in which the treated water from the reverse osmosis membrane device 31 was directly supplied to the ultraviolet irradiation device 33. The treated water from the reverse osmosis membrane device 31 (RO treated water) and the treated water from the cartridge polisher 34 (CP treated water) were measured in the same manner as in Example 2, and the measurement accuracy of the TOC concentration by the TOC meter was determined. The results are shown in Table 2.

[0038] [Table 2]

[0039] The results shown in Table 2 indicate that in Example 2, in which the EDI device 32 was located between the reverse osmosis membrane device 31 and the ultraviolet irradiation device 33, the TOC concentration measured by the TOC meter for both the EDI-treated water and the CP-treated water was more than 70% of the TOC concentration calculated from the quantitative value of isopropyl alcohol by GC-MS, and the TOC concentration could be measured accurately by the TOC meter. Furthermore, since the TOC concentration of the RO-treated water and the TOC concentration of the EDI-treated water measured by GC-MS were the same, it was found that the TOC concentration of the EDI-treated water could be treated as the TOC concentration of the RO-treated water. Meanwhile, in Comparative Example 2, the TOC meter was able to accurately measure the TOC concentration of the CP-treated water, but the measurement accuracy of the TOC concentration of the RO-treated water was poor, at 27%.

[0040] [Example 3] The water treatment management apparatus 20 of the third embodiment shown in FIG. 3 was assembled as the water treatment management apparatus of Example 3-1. Sample water was passed through this water treatment management apparatus, and the TOC concentrations of the water treated by the EDI device 32 (EDI-treated water) and the water treated by the cartridge polisher 34 (CP-treated water) were measured using a TOC meter, which is the TOC measurement device 22. The reverse osmosis membrane device 31 and ultraviolet irradiation device 33 were the same as those used in Example 2, and were operated under the same conditions. The EDI device 32 in Example 3-1 was the same as the EDI device 32 in Example 2, and was operated under the same conditions. The sample water was water to which isopropyl alcohol had been added to achieve a TOC concentration of 1000 μg / L and to which carbon dioxide had been dissolved to achieve an inorganic carbon concentration of 5 mg / L, and the pH had been adjusted to 7. The inorganic carbon concentration in the sample water was five times the TOC concentration by weight. The isopropyl alcohol concentrations of the EDI-treated water and the CP-treated water were measured by GC-MS and converted to TOC concentrations. The inorganic carbon concentrations of the EDI-treated water and the CP-treated water were also determined. Based on the TOC meter measurement results and the GC-MS measurement results, the accuracy of the TOC meter measurement was determined in the same manner as in Example 2. The results are shown in Table 3.

[0041] The water treatment management apparatus of Example 3-2 was assembled by removing the EDI device 32 from the water treatment management apparatus of Example 3-1 and adding an EDI device 36 instead of the cartridge polisher 34. The same sample water as used in Example 3-1 was passed through the water treatment management apparatus, and the TOC and inorganic carbon concentrations of the RO-treated water and the EDI-treated water were determined in the same manner as in Example 3-1, and the measurement accuracy of the TOC concentration using a TOC meter was determined. The results are shown in Table 3. Furthermore, the water treatment management apparatus of Example 3-2 from which the membrane degassing device 35 was removed is the water treatment management apparatus of Comparative Example 2 described above. Table 3 also lists the results of Comparative Example 2.

[0042] [Table 3]

[0043] As can be seen from Table 3, when the TOC concentration measured by the GC-MS method is taken as 100%, the TOC concentration measured by the TOC meter in Example 3-1 was over 99% for the EDI-treated water and over 99% for the CP-treated water, providing sufficient measurement accuracy. In Example 3-2, the TOC concentration was 88% for the RO-treated water and 95% for the EDI-treated water, providing sufficient measurement accuracy. Meanwhile, in Comparative Example 2, the TOC concentration was 27% for the RO-treated water and over 99% for the EDI-treated water, meaning that the TOC meter was unable to provide sufficient measurement accuracy for the RO-treated water.

[0044] [Example 4 and Comparative Example 3] A water treatment management system was assembled, comprising a reverse osmosis membrane device to which sample water was supplied, an ultraviolet irradiation device connected to the treated water outlet of the reverse osmosis membrane device, and an EDI device connected to the outlet of the ultraviolet irradiation device. The sample water was passed through the water treatment management system while changing its pH. The TOC concentrations of the treated water from the reverse osmosis membrane device (RO treated water) and the treated water from the EDI device (EDI treated water) were measured using a TOC meter, a TOC measuring device. In Example 4 and Comparative Example 4, the reverse osmosis membrane device, ultraviolet irradiation device, and EDI device were the same as the reverse osmosis membrane device 31, ultraviolet irradiation device 33, and EDI device 36 used in the water treatment management system 20 of Example 3, respectively, under the same operating conditions. The sample water used was water to which isopropyl alcohol was added to achieve a TOC concentration of 1000 μg / L, carbon dioxide was dissolved to achieve an inorganic carbon concentration of 3 mg / L, and the pH was adjusted to 8 (Example 4-1), 7 (Example 4-2), and 6 (Comparative Example 3). In all of Examples 4-1 and 4-2 and Comparative Example 3, the inorganic carbon concentration in the sample water was three times the TOC concentration by weight. Because pH adjustment was performed, the water treatment management system used in Examples 4-1 and 4-2 and Comparative Example 3 was equivalent to the water treatment management system 20 of the fourth embodiment shown in FIG. 4. Furthermore, the isopropyl alcohol concentration was measured for each of the RO-treated water and EDI-treated water by GC-MS and converted to TOC concentration. Based on the measurement results using the TOC meter and the GC-MS method, the measurement accuracy of the TOC concentration using the TOC meter was determined in the same manner as in Example 2. The results are shown in Table 4.

[0045] [Table 4]

[0046] As can be seen from Table 4, when the TOC concentration measured by the GC-MS method is taken as 100%, the TOC concentrations measured by the TOC meter in Examples 4-1 and 4-2 were 70% or more for both the RO-treated water and the EDI-treated water, and sufficient measurement accuracy was obtained. On the other hand, in Comparative Example 4, the measurement accuracy was less than 70% for both the RO-treated water and the EDI-treated water, and sufficient measurement accuracy could not be obtained with the TOC meter. [Explanation of symbols]

[0047] 10 Water Treatment Systems 20 Water treatment management equipment 21 Evaluation Purified Water Production Department 22 TOC measuring device 31 Reverse osmosis membrane device (RO) 32,36 Electrodeionized water generator (EDI) 33 Ultraviolet irradiation device (UV) 34 Cartridge Polisher (CP) 35 Membrane degassing device 37 pH adjustment device

Claims

1. A water treatment management device for use in managing the operation of a water treatment system, the device comprising: a test pure water production unit that performs a unit operation for removing TOC components; and a measuring means for measuring the TOC concentration of the target water. an inorganic carbon removal means provided in the pure water production unit for evaluation, the evaluation pure water producing section is provided with at least a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchanger packing device packed with an ion exchanger containing at least an anion exchanger as the equipment, and the subject water is passed through the reverse osmosis membrane device, the ultraviolet irradiation device, and the ion exchanger packing device in this order; the inorganic carbon removal means is provided at a position downstream of the reverse osmosis membrane device and upstream of the ultraviolet irradiation device in a water flow path of the subject water in the evaluation pure water production unit, The water to be measured is at least one of the target water and treated water of at least one of the devices, the inorganic carbon removal means, either alone or in cooperation with the reverse osmosis membrane device, removes inorganic carbon contained in the water to be measured; 1. A water treatment management device, wherein the inorganic carbon concentration of the water to be measured, which is supplied to the measuring means, is 10 times or less by weight of the TOC concentration measured by the measuring means.

2. 2. The water treatment management system according to claim 1, wherein the inorganic carbon removal means is an electrodeionization water production device.

3. 3. The water treatment management system according to claim 1, further comprising an additional inorganic carbon removal means to which the target water is supplied, and treated water from the additional inorganic carbon removal means is supplied to the reverse osmosis membrane device.

4. The water treatment management device according to claim 3 , wherein the additional inorganic carbon removal means is either a pH adjustment means for adjusting the pH of the target water or a degassing device.

5. A water treatment management device for use in managing the operation of a water treatment system, comprising: equipment for treating target water supplied as target water; a pure water production unit for evaluation that performs unit operations for removing TOC components; and a measuring means for measuring the TOC concentration of target water; an inorganic carbon removal means provided in the pure water production unit for evaluation, the evaluation pure water producing section is provided with at least a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchanger packing device packed with an ion exchanger containing at least an anion exchanger as the equipment, and the subject water is passed through the reverse osmosis membrane device, the ultraviolet irradiation device, and the ion exchanger packing device in this order; the inorganic carbon removal means is provided upstream of the reverse osmosis membrane device so that the target water is supplied thereto, and treated water from the inorganic carbon removal means is supplied to the reverse osmosis membrane device; The water to be measured is at least one of the target water and treated water of at least one of the devices, the inorganic carbon removal means is either a pH adjustment means for adjusting the pH of the target water or a degassing device; the inorganic carbon removal means, either alone or in cooperation with the reverse osmosis membrane device, removes inorganic carbon contained in the water to be measured; 1. A water treatment management device, wherein the inorganic carbon concentration of the water to be measured, which is supplied to the measuring means, is 10 times or less by weight of the TOC concentration measured by the measuring means.

6. 6. The water treatment management system according to claim 1, wherein the ion exchanger filling device is an electrodeionized water production device.

7. A water quality monitoring method for monitoring the water quality of target water, the target water being water to be supplied to a water treatment system, comprising: supplying the target water to a pure water production unit for evaluation that is provided separately from the water treatment system and that performs a unit operation for removing TOC components; a step of measuring the TOC concentration of the water to be measured at one or more measurement points in the pure water production unit for evaluation, which may include an inlet and an outlet of the pure water production unit for evaluation, using a measurement means; removing inorganic carbon so that the inorganic carbon concentration of the water to be measured supplied to the measuring means is 10 times or less by weight of the TOC concentration measured by the measuring means; and In the evaluation pure water producing unit, at least a reverse osmosis membrane treatment, an ultraviolet oxidation treatment, and an ion exchange treatment are performed on the subject water in this order as the unit operations; The water quality monitoring method further comprises carrying out a step of removing the inorganic carbon from the water discharged from the reverse osmosis membrane treatment and supplied to the ultraviolet oxidation treatment.

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