JP2023150986A - Water treatment control apparatus and water quality monitoring method - Google Patents

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

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.

For example, in water treatment systems such as ultrapure water production systems that generate 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, in ultrapure water production systems, reverse osmosis (RO) treatment and ultraviolet (UV) oxidation treatment are performed to remove organic substances (TOC (Total Organic Carbon) components) contained in raw water. . However, among the organic components, there are components that are easily removed by these treatments and components that are not.

Until now, tap water, local water, industrial water, etc. have been used as the raw water supplied to ultrapure water production systems. In recent years, in order to use water resources more effectively, reclaimed water or recovered water, which is obtained by first treating and reusing industrial wastewater, has been used as raw water. Unlike industrial water, the quality of reclaimed water or recovered water may not be stable, and reclaimed or recovered water may suddenly contain unexpected organic matter. In the unlikely event that organic substances that are difficult to remove are mixed into the raw water, the quality of the treated water at the outlet of the ultrapure water production system may be affected. In particular, in the case of ultrapure water production systems with large processing capacity, it takes time for the effects of changes in water quality in the raw water supplied to the system to reach the outlet, so changes in the quality of the treated water obtained from the outlet are It is not appropriate to respond to changes in raw water quality after detection. It is becoming increasingly important to monitor the quality of raw water in an ultrapure water production system and to appropriately manage the operation of the ultrapure water production system depending on the water quality.

In order to monitor the quality of raw water and appropriately manage the operation of a water treatment system such as an ultrapure water production system, it has been proposed to use a device that is provided separately from the water treatment system. This device provided separately from the water treatment system will be collectively referred to as a water treatment management device herein. The water treatment management device consists of equipment that performs the unit operations necessary to remove TOC (total organic carbon) components, and measurement means that measure the TOC concentration. If the TOC concentration in the treated water is still high after treatment to remove TOC components in the water treatment management equipment, it is determined that the raw water contains organic species that are difficult to remove using standard TOC removal operations. be able to.

Patent Document 1 discloses an evaluation pure water production section configured by combining equipment that performs unit operations necessary to remove TOC components, and measures TOC concentration at a plurality of measurement points in the evaluation pure water production section. The present disclosure discloses monitoring and evaluating the quality of raw water supplied to a water treatment system using a water treatment management device having a measuring means. The evaluation pure water production department is a pure water production system that is not equivalent to a water treatment system, and is equipped with equipment such as a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchange device in order to remove TOC components. ing. In the water treatment management device of Patent Document 1, when a cartridge polisher, which is a non-regenerative mixed bed ion exchange device, is used as the ion exchange device installed in the evaluation pure water production section, the concentration of ionic impurities in the raw water is There is a problem in that the frequency of replacement increases when the

Patent Document 2 uses a sub ultrapure water production system configured equivalently to the main ultrapure water production system, detects the TOC concentration of the outlet water of the sub ultrapure water production system, and determines the quality of the raw water. The company makes decisions and manages the operation of the main ultrapure water production system. Since the sub ultrapure water production system is equivalent to the main ultrapure water production system, a pretreatment device such as an ion exchange device is installed in the main ultrapure water production system, for example, before the reverse osmosis membrane device. If the sub-ultra-pure water production system has a similar pre-treatment device, the scale of the sub-ultra-pure water production system becomes large and the installation space of the sub-ultra-pure water production system is restricted. This may occur. In addition, when a pre-treatment device is installed, the maintenance process required for the pre-treatment device, such as the regeneration process of a regenerative ion exchange device, will be performed, so the operation method of the sub-ultra pure water production system will be changed. This increases complexity and operational costs.

Patent Document 3 discloses a monitoring device that includes an ultraviolet irradiation device and a deionization device provided after the ultraviolet irradiation device, and measures the TOC concentration of raw water supplied to the ultraviolet irradiation device and outlet water of the deionization device. is disclosed. In ultraviolet oxidation treatment carried out with an ultraviolet irradiation device, if the water to be treated contains ions or impurities, the decomposition and removal efficiency of TOC decreases, but in the monitoring device described in Patent Document 3, the ultraviolet irradiation device is There is no equipment installed to remove ions and impurities, and depending on the quality of the raw water, the UV irradiation equipment may not be able to adequately decompose and remove TOC, making it impossible to properly evaluate the quality of the raw water. There is.

Japanese Patent Application Publication No. 2019-155275 Japanese Patent Application Publication No. 2016-107249 Japanese Patent Application Publication No. 2020-159961

In order to appropriately manage the operation of the water treatment system by monitoring the quality of raw water supplied to the water treatment device, water treatment management devices provided separately from the water treatment system are described in Patent Documents 1 to 3 mentioned above. as also described, includes means for measuring TOC concentration in water. A TOC measurement device that measures the TOC concentration in sample water uses some method to oxidize the TOC component in sample water to carbonic acid (carbon dioxide), then measures the concentration of the generated carbonic acid in some way and converts it to TOC concentration. Things are common. In recent years, measurement devices that decompose TOC components in sample water by ultraviolet oxidation treatment, quantify the amount of carbon dioxide generated by the decomposition of TOC, and convert it into TOC concentration have been widely used. In this case, the method for quantifying the amount of carbonic acid is to measure the electrical conductivity of the sample water and the electrical conductivity after UV oxidation treatment of the sample water, and convert the difference in electrical conductivity into the carbonic acid concentration. Commonly used. However, in this method, if the sample water contains conductive ions other than carbonic acid, these ions will affect the TOC concentration measurement. As a TOC concentration measurement method that is not affected by the concentration of ions contained in sample water, there is a method of measuring conductivity using a gas permeable membrane. The method using a gas-permeable membrane involves generating carbonic acid through ultraviolet oxidation treatment, separating only the carbonic acid using a gas-permeable membrane, dissolving it in deionized water, and measuring the conductivity of the deionized water in which carbonic acid has been dissolved. This is converted into TOC concentration. A method using a gas permeable membrane is a method that allows the TOC concentration of sample water to be measured without being affected by other ions.

The TOC concentration measurement method in sample water oxidizes the TOC component in the sample water to generate carbonic acid, so it is affected by the inorganic carbon (IC) component in the sample water, and the amount of carbon dioxide generated due to oxidative decomposition of the TOC component is affected by the inorganic carbon (IC) component in the sample water. The amount of carbonic acid actually measured when measuring the amount of carbonic acid includes that derived from inorganic carbon components. Inorganic carbon components contained in sample water or raw water are basically considered to be carbon dioxide, carbonate ions, bicarbonate ions, or salts thereof. In an actual TOC concentration device, the total carbon (TC) concentration is determined from the amount of carbon dioxide measured after ultraviolet oxidation treatment, and the inorganic carbon concentration is also determined from the sample water before ultraviolet oxidation. The TOC concentration is often obtained by subtracting the inorganic carbon concentration from the concentration. When measuring a minute amount of TOC concentration, for example, a TOC concentration on the order of μg/L, using such a TOC measurement device, if the carbonate concentration in the sample water is high, the accuracy of TOC concentration measurement deteriorates. There is also a method in which the method is combined with a device that removes carbonic acid components from the sample water, but in that case, there is a possibility that TOC components eluted from the carbonic acid removing device may affect the TOC measurement value. None of the techniques described in Patent Documents 1 to 3 mentioned above take into consideration the influence of inorganic carbon components during TOC measurement, and as a result, it is difficult to measure TOC concentration or to develop a water treatment system based on TOC concentration. Management can be difficult.

An object of the present invention is to provide a water treatment management device and a water quality monitoring method for monitoring and evaluating water supplied to a water treatment system for the purpose of operational management of the water treatment system. An object of the present invention is to provide a water treatment management device and a water quality monitoring method that can accurately measure total organic carbon (TOC) concentration without being affected by IC) components.

The water treatment management device of the present invention is equipped with a device that performs treatment on the target water when water to be supplied to the water treatment system is supplied as target water, and is for evaluation that executes a unit operation for removing TOC components. In a water treatment management device used for operational management of a water treatment system, which includes a pure water production section and a measuring means for measuring the TOC concentration of the water to be measured, the water treatment management device is provided in the evaluation pure water production section to measure the TOC concentration of the water to be measured. Equipped with an inorganic carbon removal means for removing inorganic carbon contained in water, the evaluation pure water production department is equipped with equipment such as a reverse osmosis membrane device, an ultraviolet irradiation device, and an ion exchanger containing at least an anion exchanger. The target water is passed through the reverse osmosis membrane device, the ultraviolet irradiation device, and the ion exchanger filling device in this order, and the water to be measured is provided with at least the target water and at least one ion exchanger filling device. The inorganic carbon removal means, which is at least one of the treated water of the equipment, removes inorganic carbon contained in the water to be measured, either alone or in cooperation with a reverse osmosis membrane device, and removes the inorganic carbon contained in the water to be measured, which is supplied to the measurement means. The inorganic carbon concentration of the water is 10 times or less by weight the TOC concentration measured by the measuring means.

The water quality monitoring method of the present invention is a water quality monitoring method for monitoring the water quality of target water using water to be supplied to a water treatment system as target water, and is provided separately from the water treatment system to remove TOC components. a step of supplying target water to a pure water production section for evaluation that performs a unit operation for the purpose of the test, and measurement at one or more measurement points in the pure water production section for evaluation, which may include an inlet and an outlet of the pure water production section for evaluation. A step of measuring the TOC concentration of the target water by a measuring means, and a step of measuring the TOC concentration of the target water by measuring the inorganic carbon concentration so that the inorganic carbon concentration of the target water supplied to the measuring means is 10 times by weight or less the TOC concentration measured value by the measuring means. and a step of removing.

According to the present invention, in a water treatment management device and a water quality monitoring method for monitoring and evaluating water supplied to a water treatment system for operation management of the water treatment system, an influence on inorganic carbon components contained in water to be monitored is provided. It becomes possible to accurately measure TOC concentration without being affected.

1 is a diagram showing the configuration of a water treatment management device according to a first embodiment of the present invention. It is a figure showing the composition of the water treatment management device of a 2nd embodiment. It is a figure showing the composition of the water treatment management device of a 3rd embodiment. It is a figure showing the composition of the water treatment management device of a 4th embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings.

[First embodiment]
FIG. 1 shows a water treatment management device according to a first embodiment of the present invention. For example, assuming that there is a water treatment system 10 such as an ultrapure water production system, the water treatment management device 20 based on the present invention is used for operational management of the water treatment system 10 and supplies water to the water treatment system 10. The water quality of the target water is monitored and evaluated using this raw water as the target water. Raw water may be, for example, industrial water or recovered water, but in the following explanation, 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 be able to switch and supply raw water from different sources. In the illustrated example, two systems of raw water can be switched (or mixed) and supplied to the water treatment system 10. Therefore, valves 11 and 12 are provided in the two systems of raw water pipes, and these pipes merge on the outlet sides of valves 11 and 12, and a valve 15 is further provided between the confluence point C and the water treatment system 10. It is being A pipe 16 for supplying raw water to the water treatment management device 20 branches from a position between the confluence C and the valve 15. The valve 15 is provided to enable monitoring and evaluation of the quality of raw water even when the supply of raw water to the water treatment system 10 is cut off. For example, the water treatment management device 20 confirms the presence of persistent TOC components in raw water, which is the target water, and monitors its concentration, and controls the opening and closing of the valves 11, 12, and 15 based on the obtained results. By doing so, it is possible to control which supply source and at what flow rate raw water is supplied to the water treatment system 10. Here, the persistent TOC component refers to a TOC component that is difficult to remove by reverse osmosis membrane treatment or ultraviolet oxidation treatment, particularly a TOC component that is difficult to decompose and remove by general ultraviolet oxidation treatment.

Roughly divided, the water treatment management device 20 includes an evaluation pure water production section 21 and a TOC (total organic carbon) measuring device 22. The evaluation pure water production unit 21 is a device that is supplied with target water through the piping 16 and produces pure water from the target water, and is configured by combining multiple types of equipment that process the target water. There is. Some of these devices include those that perform unit operations to remove TOC components. The evaluation pure water production unit 21 of the water treatment management device 20 based on the present invention includes a reverse osmosis membrane device (RO) 31 as a device for treating target water, and water treated by the reverse osmosis membrane device 31 is supplied. It is equipped with at least an ultraviolet irradiation device (UV) 33 that performs ultraviolet oxidation treatment, and a deionization device filled with an ion exchanger and supplied with water from the outlet of the ultraviolet irradiation device 33. The ion exchanger filled in the deionization device contains at least an anion exchanger. In the water treatment management device 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.

The TOC measurement device 22 is a device that measures the TOC concentration of water at one or more measurement points within the evaluation pure water production section 21. The measurement points may include the inlet and outlet of the pure water production section 21 for evaluation, and in that case, the TOC measurement device 22 measures the TOC concentration of the target water itself supplied to the pure water production section 21 for evaluation. Also, the TOC concentration of the outlet water of the evaluation pure water production section 21 is measured. As the TOC measuring device 22, a commercially available online TOC measuring device, a TOC concentration meter, a TOC meter, or the like can be used. When managing the operation of the water treatment system 10, which is an ultrapure water production system, the TOC concentration of the outlet water of the evaluation pure water production section 21 (in the example shown in FIG. 1, the treated water of the cartridge polisher 34) and the reverse osmosis membrane It is preferable that the TOC measuring device 22 measure at least one of the TOC concentration of the water treated by the device 31 and before being treated by the ultraviolet irradiation device 33. By the way, when the TOC concentration in the water to be measured is low, for example about μg/L, and when the IC (inorganic carbon) concentration contained therein is high, the accuracy of the TOC concentration measured by the TOC measuring device 22 decreases. I know that. The present inventors believe that if the IC concentration of the water to be measured is 10 times or less by weight compared to the TOC concentration value obtained when the water is measured with the TOC measuring device 22, the TOC concentration measured by the TOC measuring device 22 is It has been found that measurement errors are reduced and the operation of the water treatment system 10 can be managed stably. The IC concentration of the water to be measured is preferably 6 times or less, more preferably 3 times or less by weight, the TOC concentration measured by the TOC measuring device 22.

Therefore, in the water treatment management device 20 of the first embodiment, the evaluation pure water production section 21 includes a reverse osmosis membrane device 31 equipped with a reverse osmosis membrane and to which target water is supplied via the piping 16, and a reverse osmosis membrane device An electrodeionized water production device (hereinafter also referred to as an EDI device) 32 is connected to the outlet of the EDI device 31 and is supplied with permeated water from the reverse osmosis membrane; It includes at least an ultraviolet irradiation device 33 that performs ultraviolet oxidation treatment on water, and a deionization device filled with an ion exchanger and to which treated water of the ultraviolet irradiation device 33 is supplied. The ion exchanger filled in the deionization device contains at least an anion exchanger. In the water treatment management device 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 is branched off and supplied to the TOC measuring device 22 via the valve 52 . Further, a part of the outlet water of the evaluation pure water production section 21 is branched and supplied to the TOC measuring device 22 via the valve 54. By controlling the opening and closing of the valves 52 and 54, the TOC measurement device 22 can switch and measure the TOC concentration of the treated water of the EDI device 32 and the TOC concentration of the outlet water of the evaluation pure water production section 21. . The remaining portion of the outlet water of the pure water production section 21 for evaluation is collected or discharged. Since the reverse osmosis membrane device 31 is provided in the evaluation pure water production section 21 to remove TOC components, in the following explanation, two types of water discharged from the reverse osmosis membrane device 31, namely the reverse osmosis membrane Of the water that has passed through and the concentrated water, the water that has passed through the reverse osmosis membrane is used as the treated water of the reverse osmosis membrane device 31.

In the water treatment management device 20 shown in FIG. 1, the EDI device 32 is provided to remove inorganic carbon components contained in the water treated by the reverse osmosis membrane device 31. The EDI device 32 is a device that includes a desalination chamber filled with an ion exchanger and generates deionized water by combining electrophoresis and electrodialysis, and water to be treated is supplied to the desalination chamber. This device simultaneously deionizes (desalts) the water using an ion exchanger and regenerates the ion exchanger. The water that has been desalinated in the desalination chamber is discharged from the desalination chamber as treated water of the EDI device 32. Therefore, the EDI device 32 is included in the category of an ion exchanger filling device.

While the EDI device 32 can efficiently remove inorganic carbon components represented by carbonic acid, it does not remove nonionic TOC components, or even if it removes them, it does so only to a limited extent. Therefore, the TOC concentration of the water treated by the EDI device 32 can be treated as the TOC concentration of the water treated by the reverse osmosis membrane device 31, and since inorganic carbon components are removed by the EDI device 32, the By measuring the TOC concentration of water, it becomes possible to stably and more accurately measure the TOC concentration in the water treated by the reverse osmosis membrane device 31. It is also possible to use an ion exchanger packing device such as a general ion exchange resin tower that is simply filled with ion exchange resin to remove inorganic carbon components, but if the ion load in the water to be treated is high. Inorganic carbon components begin to leak in a short period of time, requiring 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 regeneration of the ion exchanger proceed simultaneously in the demineralization chamber, which is necessary in a general ion exchange resin column. Does not require regeneration processing. By using the EDI device 32, it is possible to stably remove inorganic carbon components over a long period of time even when the inorganic carbon load is relatively high.

The installation position of the EDI device 32, which is used to remove inorganic carbon components that cause errors in TOC concentration measurement, is not particularly limited, but as shown in FIG. It is preferable that the ultraviolet ray irradiation device 33 be provided before the ultraviolet irradiation device 33. In the water treatment management device 20 shown in FIG. 1, since the reverse osmosis membrane device 31 and the EDI device 32 can highly remove ionic components in the water to be treated, the TOC decomposition efficiency in the ultraviolet irradiation device 33 can be improved. At the same time, it is possible to reduce the ion load on the ion exchanger filling device such as the cartridge polisher 34 placed after the ultraviolet irradiation device 33, and it becomes unnecessary to frequently regenerate or replace the ion exchanger filling device. . In the first embodiment, the cartridge polisher 34 may be replaced by a further EDI device.

[Second embodiment]
Since the inorganic carbon component in the target water supplied to the water treatment management device 20 is usually a carbonic acid component, a deaerator can be used to remove the inorganic carbon. As the degassing device, for example, a decarbonation membrane device can be used. Although there is no particular restriction on the installation location of the deaeration device, it is preferable to install it in the front stage of the reverse osmosis membrane device 31. A degassing device may be provided at a position between the reverse osmosis membrane device 31 and the ultraviolet irradiation device 33. When a deaeration device is provided, it is not necessary to provide the EDI device 32 at a position downstream of the reverse osmosis membrane device 31 and upstream of the ultraviolet irradiation device 33. When a deaeration device is provided upstream of the reverse osmosis membrane device 31, the water treatment management device measures the TOC concentration of the treated water of the deaeration device, the TOC concentration of the treated water of the reverse osmosis membrane device 32, and the pure water production section for evaluation. Preferably, the TOC concentration of at least one of the 21 outlet water TOC concentrations is measured. In order to efficiently remove inorganic carbon in the form of carbonate and hydrogen carbonate using the deaerator, a pH adjustment means is provided upstream of the deaerator to adjust the liquid properties of the water supplied to the deaerator. It can also be adjusted to the acidic side.

FIG. 2 shows a water treatment management device 20 according to a second embodiment of the invention, including a deaerator. The water treatment management device 20 shown in FIG. 2 is the same as the water treatment management device 20 shown in FIG. An EDI device 36 is provided in place of the polisher 34. Therefore, in the evaluation pure water production section 21 of the water treatment management device 20 shown in FIG. The treated water is supplied as it is to the ultraviolet irradiation device 33, the treated water of the ultraviolet irradiation device 33 is supplied to the EDI device 36, and the treated water of the EDI device 36 serves as the outlet water of the pure water production section 21 for evaluation. A portion of the treated water from the membrane deaerator 35 is branched off and supplied to the TOC measurement device 22 via the valve 55, and a portion of the treated water from the reverse osmosis membrane device 31 is branched off and supplied via the valve 51. A part of the outlet water of the pure water production section 21 for evaluation is branched and supplied to the TOC measurement device 22 via a valve 56 . By controlling the opening and closing of the valves 51, 55, and 56, the TOC measurement device 22 measures the TOC concentration of the treated water from the membrane deaerator 35, the TOC concentration of the treated water from the reverse osmosis membrane device 31, and the pure water production unit for evaluation. The TOC concentration of the outlet water of No. 21 can be switched and measured. Further, in the water treatment management device 20 shown in FIG. 2, since the EDI device 36 is used instead of the cartridge polisher 34, it is possible to stably remove TOC components even when the ion load is high.

[Third embodiment]
FIG. 3 shows a water treatment management device 20 according to a third embodiment of the present invention. The water treatment management device 20 shown in FIG. 3 is equipped with a degassing device like the one shown in FIG. 2, and specifically, in the water treatment management device 20 shown in FIG. A membrane deaerator 35 is provided at the front stage, and target water is supplied to the reverse osmosis membrane device 31 via the membrane deaerator 35 in the evaluation pure water production section 21. When the membrane deaerator 35 is provided in this way, any one of the treated water of the membrane deaerator 35, the treated water of the reverse osmosis membrane device 31, the treated water of the EDI device 32, and the treated water of the cartridge polisher 34 is used. Preferably, TOC concentration is measured. In the system shown in FIG. 3, a portion of the treated water from the membrane deaerator 35 is branched off and supplied to the TOC measuring device 22 via the valve 55, and a portion of the treated water from the reverse osmosis membrane device 31 is branched off. A part of the treated water of the EDI device 32 is branched and supplied to the TOC measuring device 22 via the valve 52, and the outlet water of the pure water production section 21 for evaluation is supplied to the TOC measuring device 22 via the valve 51. A portion thereof is branched and supplied to the TOC measuring device 22 via a valve 54. By controlling the opening and closing of the valves 51, 52, 54, and 55, the TOC measuring device 22 can measure the TOC concentration of the treated water from the membrane deaerator 35, the TOC concentration of the treated water from the reverse osmosis membrane device 31, and the TOC concentration of the EDI device 32. The TOC concentration of the treated water and the TOC concentration of the outlet water of the evaluation pure water production section 21 can be switched and measured. In the water treatment management device 20 shown in FIG. 3 as well, a pH adjusting means may be provided upstream of the membrane deaerator 35, and in that case, the liquidity of the water supplied to the membrane deaerator 35 is adjusted to the acidic side. It is preferable to do so.

[Fourth embodiment]
In the second and third embodiments described above, the pH adjustment means can be provided upstream of the deaeration device, but the pH adjustment device is provided upstream of the reverse osmosis membrane device, and the pH is adjusted by the pH adjustment device. Water can be supplied to the reverse osmosis membrane device to facilitate the removal of inorganic carbon. The pH adjusting means cooperates with a reverse osmosis membrane device to remove inorganic carbon contained in the water to be measured. In that case, it is preferable to adjust the liquidity of the water supplied to the reverse osmosis membrane device to be alkaline. Inorganic carbon contained in water mainly exists in the form of carbon dioxide (CO ₂ ), carbonate ion (CO ₃ ²⁻ ), and hydrogen carbonate ion (HCO ₃ ⁻ ), and the abundance ratio among them varies depending on the pH. different. On the alkaline side, the proportion of carbonate ions, which are polyvalent ions, increases, making them easier to remove by the reverse osmosis membrane. When a pH adjustment means is provided before the reverse osmosis membrane device, it is preferable to connect an ultraviolet irradiation device and an EDI device after the reverse osmosis membrane device in this order. It is preferable to measure at least one of the TOC concentration of water and the TOC concentration of water treated by the EDI device. Alternatively, an EDI device, an ultraviolet irradiation device, and a cartridge polisher may be connected in this order after the reverse osmosis membrane device, and when connected in this way, the TOC concentration of the treated water of the reverse osmosis membrane device, the treatment of the EDI device It is preferable to measure at least one of the TOC concentration of water and the TOC concentration of water treated by a cartridge polisher.

FIG. 4 shows a water treatment management device 20 according to a fourth embodiment of the present invention. The water treatment management device 20 shown in FIG. 4 is the same as the water treatment management device 20 shown in FIG. , the pH of the target water supplied to the reverse osmosis membrane device 31 can be adjusted by a pH adjustment device 37. A portion of the treated water from the reverse osmosis membrane device 31 is supplied to the TOC measuring 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 switches and measures the TOC concentration of the treated water of the reverse osmosis membrane device 31 and the TOC concentration of the outlet water of the evaluation pure water production section 21. I can do it.

The example of the water treatment management device 20 based on the present invention has been described above. Once the TOC concentration is obtained in the water treatment management device 20, based on the TOC concentration, the operating conditions of the reverse osmosis membrane device and the ultraviolet irradiation device included in the water treatment system 10 (for example, the recovery rate in the reverse osmosis membrane device, the The amount of ultraviolet irradiation in the irradiation device) may also be controlled. A control mechanism for controlling the operating conditions of the water treatment system 10 in this manner may be provided within the water treatment management device 20. When it is possible to supply raw water to the water treatment system 10 from a plurality of supply sources, as described in Patent Document 1, water is The raw water actually supplied to the treatment system 10 may be switched. Furthermore, instead of the raw water supplied to the inlet of the water treatment system 10, the water flowing inside the water treatment system 10 during the process of generating ultrapure water from raw water is branched and this water is used as target water for the water treatment management system. 20 may be supplied. For example, when a filter, an activated carbon device, a primary pure water system, etc. are provided on the inlet side of the water treatment system 10, the outlet water of these filters, activated carbon device, or primary pure water system is supplied to the water treatment management device 20, The operation of the water treatment system 10 may also be managed.

In the water treatment management device 20 according to the present invention, in order to prevent the reverse osmosis membrane from deteriorating due to the oxidizing agent, it is more preferable to provide an oxidizing agent removal means on the upstream side of the reverse osmosis membrane device 31. In the present invention, the inorganic carbon (IC) concentration contained in the water to be measured is set to be 10 times or less by weight the TOC concentration value obtained by the TOC measurement device, and the water treatment management device 20 is configured to satisfy this condition. The operating conditions of each device may be controlled. For example, the current value and water flow rate value (SV value) in the EDI device, and the recovery rate in the reverse osmosis membrane device may be controlled.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

[Example 1 and Comparative Example 1]
Water in which carbon dioxide was dissolved as an inorganic carbon (IC) component and isopropyl alcohol was added as a TOC component was prepared and used as sample water. The only TOC component contained in the sample water is isopropyl alcohol, and by quantifying isopropyl alcohol in the sample water using the GC-MS (gas chromatography-mass spectrometry) method, the accurate TOC concentration in the sample water can be determined. TOC concentration was adjusted to 10 μg/L and 100 μg/L. The TOC concentration of the sample water was measured using a TOC meter while changing the inorganic carbon concentration by changing the amount of carbon dioxide added, and the measurement accuracy of the TOC concentration with the TOC meter was determined. As the TOC meter, Sievers M500e manufactured by SUEZ was used. This TOC meter is capable of measuring the inorganic carbon (IC) concentration in the sample water at the same time as measuring the TOC concentration, and the inorganic carbon concentration was also determined at the same time as the TOC concentration. The results are shown in Table 1. In Table 1, "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 the measurement by GC-MS being taken as 100%.

It was found that in Examples 1-1 to 1-12 in which the IC/TOC weight ratio was 10 or less, the measurement accuracy was 70% or more, and the TOC concentration could be measured within an accuracy range of 30% or less. In particular, in Examples 1-1 to 1-4 and 1-7 to 1-10, in which the IC/TOC weight ratio is 3 or less, the measurement accuracy is 90% or more, and the TOC concentration can be determined within an accuracy range of 10%. I was able to measure it. On the other hand, in Comparative Examples 1-1 to 1-4 in which the IC/TOC weight ratio exceeds 10, the measurement accuracy was less than 70%. As the IC/TOC weight ratio increased, the measurement accuracy deteriorated significantly.

[Example 2]
The water treatment management device 20 of the first embodiment shown in FIG. The TOC concentration of water) and the TOC concentration of treated water (CP treated water) of the cartridge polisher 34 were measured using a TOC meter which is the TOC measuring device 22. As sample water, water was used in which isopropyl alcohol was added so that the TOC concentration was 1000 μg/L, carbon dioxide was dissolved so that the inorganic carbon concentration was 10 mg/L, and the pH was adjusted to 7. At this time, the inorganic carbon concentration in the sample water is 10 times the TOC concentration by weight. In addition, the isopropyl alcohol concentration was measured by the GC-MS method for each of the treated water (RO treated water), EDI treated water, and CP treated water of the reverse osmosis membrane device 31, and was converted into a TOC concentration. Based on the measurement results with the TOC meter and the measurement results with the GC-MS method, the measurement accuracy of TOC concentration with the TOC meter was determined in the same manner as in Example 1. The results are shown in Table 2.

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 was one in which the demineralization chamber was divided into a first small demineralization chamber on the anode side and a second small demineralization chamber on the cathode side with an intermediate ion exchange membrane in between. The first small demineralization chamber was filled with a cation exchange resin (CER), and the second small demineralization chamber was filled with an anion exchange resin (AER). The concentration chamber and the cathode chamber were filled with an anion exchange resin, and the anode chamber was filled with a 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 set to 0.4 kWh/m ³ .

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

From the results shown in Table 2, in Example 2 in which the EDI device 32 is placed between the reverse osmosis membrane device 31 and the ultraviolet irradiation device 33, the TOC concentration measured by the TOC meter was was 70% or more of the TOC concentration calculated from the quantitative value of isopropyl alcohol by GC-MS method, and the TOC concentration could be measured with high accuracy by the TOC meter. Furthermore, since the TOC concentration of RO treated water and EDI treated water are the same as determined by the GC-MS method, it was found that the TOC concentration of EDI treated water can be treated as the TOC concentration of RO treated water. . On the other hand, in Comparative Example 2, the TOC meter was able to accurately measure the TOC concentration of CP-treated water, but the TOC concentration of RO-treated water had a poor measurement accuracy of 27%.

[Example 3]
The water treatment management device 20 of the third embodiment shown in FIG. The TOC concentration of the EDI treated water) and the TOC concentration of the treated water of the cartridge polisher 34 (CP treated water) were measured using a TOC meter which is the TOC measuring device 22. As the reverse osmosis membrane device 31 and the ultraviolet irradiation device 33, the same ones used in Example 2 were used under the same operating conditions. The EDI device 32 in Example 3-1 was the same as the EDI device 32 in Example 2, and was used under the same operating conditions. As sample water, water was used in which isopropyl alcohol was added so that the TOC concentration was 1000 μg/L, carbon dioxide was dissolved therein so that the inorganic carbon concentration was 5 mg/L, and the pH was adjusted to 7. At this time, the inorganic carbon concentration in the sample water is 5 times the TOC concentration by weight. In addition, the isopropyl alcohol concentration was measured using the GC-MS method for each of the EDI-treated water and the CP-treated water and converted to the TOC concentration. Inorganic carbon concentrations were also determined for EDI-treated water and CP-treated water. Based on the measurement results with the TOC meter and the measurement results with the GC-MS method, the measurement accuracy of TOC concentration with the TOC meter was determined in the same manner as in Example 2. The results are shown in Table 3.

The EDI device 32 was removed from the water treatment management device of Example 3-1, and an EDI device 36 was installed in place of the cartridge polisher 34, which was assembled as the water treatment management device of Example 3-2. The same sample water used in was passed through the water treatment management device, and the TOC concentration and inorganic carbon concentration of the RO treated water and the TOC concentration and inorganic carbon concentration of the EDI treated water were measured in the same manner as in Example 3-1. The measurement accuracy of TOC concentration using a TOC meter was determined. The results are shown in Table 3. Furthermore, the water treatment management device of Example 3-2 from which the membrane deaerator 35 was removed is the water treatment management device of Comparative Example 2 described above. Table 3 also shows the results of Comparative Example 2.

From Table 3, when the TOC concentration determined by the GC-MS method is taken as 100%, the TOC concentration determined by the TOC meter exceeds 99% for EDI treated water and 99% for CP treated water in Example 3-1. was obtained, and sufficient measurement accuracy was obtained. In Example 3-2, sufficient measurement accuracy was also obtained, with the measurement accuracy being 88% for RO treated water and 95% for EDI treated water. On the other hand, in Comparative Example 2, it was 27% for RO-treated water and more than 99% for EDI-treated water, and it was not possible to obtain sufficient measurement accuracy with the TOC meter for RO-treated water.

[Example 4 and Comparative Example 3]
Assemble a water treatment management device consisting of a reverse osmosis membrane device to which sample water is 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 is passed through this water treatment management device while changing the pH of the water, and the TOC concentration of the water treated by the reverse osmosis membrane device (RO treated water) and the TOC concentration of the treated water of the EDI device (EDI treated water) are measured. It was measured using a TOC meter. In Example 4 and Comparative Example 4, the reverse osmosis membrane device 31, ultraviolet irradiation device 33, and EDI device used in the water treatment management device 20 of Example 3 were used as the reverse osmosis membrane device, ultraviolet irradiation device, and EDI device, respectively. The same device as apparatus 36 was used under the same operating conditions. As sample water, isopropyl alcohol was added so that the TOC concentration was 1000 μg/L, carbon dioxide was dissolved so that the inorganic carbon concentration was 3 mg/L, and the pH was adjusted to 8 (Example 4-1), 7 (Example 4-2) and water adjusted to 6 (Comparative Example 3) were used. In both Examples 4-1 and 4-2 and Comparative Example 3, the inorganic carbon concentration in the sample water was 3 times the TOC concentration by weight. Since the pH is adjusted, the water treatment management device used in Examples 4-1, 4-2 and Comparative Example 3 is equivalent to the water treatment management device 20 of the fourth embodiment shown in FIG. It is. In addition, the isopropyl alcohol concentration was measured using the GC-MS method for each of the RO-treated water and the EDI-treated water and converted into the TOC concentration. Based on the measurement results with the TOC meter and the measurement results with the GC-MS method, the measurement accuracy of TOC concentration with the TOC meter was determined in the same manner as in Example 2. The results are shown in Table 4.

From Table 4, when the TOC concentration determined by the GC-MS method is taken as 100%, the TOC concentration determined by the TOC meter was 70% for both the RO treated water and the EDI treated water in Examples 4-1 and 4-2. % or more, 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 the TOC meter was unable to obtain sufficient measurement accuracy.

10 Water treatment system 20 Water treatment management device 21 Pure water production department for evaluation 22 TOC measurement device 31 Reverse osmosis membrane device (RO)
32,36 Electrodeionized water production equipment (EDI)
33 Ultraviolet irradiation device (UV)
34 Cartridge polisher (CP)
35 Membrane deaerator 37 pH adjustment device

Claims (10)

Water to be supplied to the water treatment system is supplied as target water and includes equipment for processing the target water, and an evaluation pure water production unit that performs unit operations for removing TOC components, and a measurement target A water treatment management device used for operational management of the water treatment system, comprising: a measuring means for measuring the TOC concentration of the water;
An inorganic carbon removal means provided in the evaluation pure water production section,
In the pure water production department for evaluation, 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 are provided as the equipment, and the target Water is passed through the reverse osmosis membrane device, the ultraviolet irradiation device, and the ion exchanger filling device in this order,
The water to be measured is at least one of the target water and the treated water of at least one of the devices,
The inorganic carbon removing means removes inorganic carbon contained in the water to be measured, either alone or in cooperation with the reverse osmosis membrane device,
A water treatment management device characterized in that the inorganic carbon concentration of the water to be measured that is supplied to the measuring means is 10 times or less by weight the TOC concentration measured by the measuring means. Claim: 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 the water flow path of the target water in the evaluation pure water production section. 1. The water treatment management device according to 1. The water treatment management device according to claim 2, wherein the inorganic carbon removal means is an electrodeionized water production device. Water treatment management according to claim 2 or 3, wherein the additional inorganic carbon removal means to which the target water is supplied is provided, and the treated water of the additional inorganic carbon removal means is supplied to the reverse osmosis membrane device. Device. The water treatment management device according to claim 4, wherein the additional inorganic carbon removal means is either a pH adjustment means for adjusting the pH of the target water or a deaerator. 2. The method according to claim 1, wherein the inorganic carbon removing means is provided upstream of the reverse osmosis membrane device so that the target water is supplied, and the treated water of the inorganic carbon removing means is supplied to the reverse osmosis membrane device. The water treatment management device described. The water treatment management device according to claim 6, wherein the inorganic carbon removing means is either a pH adjusting means for adjusting the pH of the target water or a deaerator. The water treatment management device according to any one of claims 1 to 7, wherein the ion exchanger filling device is an electrodeionized water production device. A water quality monitoring method for monitoring the water quality of target water using water to be supplied to a water treatment system as target water, the method comprising:
supplying the target water to an evaluation pure water production unit that is provided separately from the water treatment system and executes a unit operation for removing TOC components;
Measuring the TOC concentration of water to be measured at one or more measurement points in the pure water production section for evaluation, which may include an inlet and an outlet of the pure water production section for evaluation, using a measuring 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 the TOC concentration measured by the measuring means;
A method for monitoring water quality. The water quality management method according to claim 9, wherein in the evaluation pure water production unit, at least a reverse osmosis membrane treatment, an ultraviolet oxidation treatment, and an ion exchange treatment are performed in this order on the target water as the unit operations. .

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