JP2011240344A - Water treatment apparatus for manufacturing ultrapure water - Google Patents

Abstract

A gas component addition means for adding gas or gas-dissolved water to water to be treated and an ultraviolet irradiation device for irradiating water from the gas component addition means with ultraviolet rays to decompose the material to be treated. In the water treatment apparatus for pure water production, the gas addition amount is made appropriate.
The raw water of ultrapure water is stored in a storage tank 2, supplied through a supply pipe 3 and a supply pump 4, and added with oxygen by an oxygen supply device 5. Processing is performed by the gas device 7, the ion exchange device 8, and the ultrafiltration device 9, respectively, and ultrapure water is supplied to the use point. The amount of oxygen from the oxygen supply device 5 is controlled based on the signal from the dissolved oxygen meter 13 according to the TOC concentration behavior on the primary side of the UV irradiation device 6.
[Selection] Figure 1

Description

  The present invention relates to a water treatment apparatus for producing ultrapure water provided with an ultraviolet irradiation device, and a water treatment system for producing ultrapure water comprising this water treatment apparatus for producing ultrapure water.

  In general, an apparatus for producing ultrapure water used for cleaning silicon wafers or the like is generally used in a primary pure water system into which treated water of a pretreatment system is introduced and a secondary in which treated water of a primary pure water system is introduced. And a pure water system (subsystem). The primary pure water system is composed of an ion exchange device, reverse osmosis membrane device, deaeration device, ultraviolet sterilization device, etc., and most of impurities such as fine particles, ionic components, organic substances, colloidal components contained in the water to be treated. To be removed. The secondary pure water system includes a treated water introduction tank, an ultraviolet oxidizer, a cartridge polisher (non-regenerative mixed bed ion exchanger), an ultrafiltration membrane device, and the like of the primary pure water system. It removes a trace amount of impurities remaining in the treated water of the system (for example, JP-A-9-253639).

  In JP-A-9-253639, after removing dissolved nitrogen from pure water from a primary pure water system by a degassing device, oxygen or ozone is added, and then supplied to an ultraviolet irradiation device to oxidize TOC. It is described that the decomposition efficiency is improved. In paragraph 0015 of the same publication, if dissolved oxygen is present in the water treated by the ultraviolet irradiation apparatus, it is described that hydroxyl radicals and hydrogen peroxide are generated by the ultraviolet irradiation, and the TOC decomposition efficiency is improved. .

JP-A-9-253639

  The present invention has a gas component addition means for adding gas or gas-dissolved water to the water to be treated, and an ultraviolet irradiation device for irradiating the water from the gas component addition means with ultraviolet rays to decompose the material to be treated. An object of the present invention is to make an appropriate amount of gas component addition in a water treatment apparatus for producing ultrapure water.

  In one aspect of the present invention, an object of the present invention is to provide a water treatment device for producing ultrapure water and a water treatment system for producing ultrapure water that can sufficiently decompose an organic substance (TOC component) with an appropriate oxygen addition amount. And

  In another aspect, the present invention provides an ultrapure water production water treatment device and an ultrapure water production water treatment system capable of sufficiently decomposing hydrogen peroxide with an appropriate hydrogen addition amount. Objective.

  The water treatment apparatus for producing ultrapure water according to the present invention (Claim 1) includes a gas component addition means for adding gas or gas-dissolved water to the water to be treated, and water from the gas component addition means by irradiating the water with ultraviolet rays. In an ultrapure water production water treatment device having an ultraviolet irradiation device for decomposing the material to be treated, the concentration of the material to be treated, the gas component concentration or the product concentration in the water provided in the preceding stage or the subsequent stage of the ultraviolet irradiation device. Measuring means for measuring, and control means for controlling the amount of gas or gas dissolved water added by the gas component adding means based on the measurement result of the measuring means.

  A water treatment apparatus for producing ultrapure water according to a second aspect is the water treatment apparatus according to the first aspect, wherein the material to be treated is an organic substance, the gas is oxygen, and the measuring means sets the dissolved oxygen concentration to the upstream of the gas component addition means. And it measures by at least one of the back | latter stage of the said ultraviolet irradiation device, It is characterized by the above-mentioned.

  The water treatment apparatus for producing ultrapure water according to claim 3 is the water treatment apparatus according to claim 1, wherein the material to be treated is an organic substance, the gas is oxygen, and the measuring means is a means for adding dissolved oxygen concentration and dissolved organic substance concentration to the adding means. , And at least one of the subsequent stage of the ultraviolet irradiation device.

  According to a fourth aspect of the present invention, there is provided a water treatment apparatus for producing ultrapure water according to the first aspect, wherein the gas is hydrogen, the substance to be treated in the water to be treated is hydrogen peroxide, and the measuring means is from the ultraviolet irradiation apparatus. It measures the dissolved hydrogen concentration in water.

  The ultrapure water production water treatment device according to claim 5 is the water treatment device according to claim 1, wherein the gas is hydrogen, the material to be treated in the water to be treated is hydrogen peroxide, and the measuring means is from the ultraviolet irradiation device. It measures the dissolved hydrogen peroxide concentration in water.

  The water treatment system for producing ultrapure water according to claim 6 is a first ultrapure water production water treatment device and a second ultrapure water production for treating treated water from the first ultrapure water production water treatment device. A water treatment system for producing ultrapure water comprising a water treatment device, wherein the first ultrapure water production water treatment device is the water treatment device for ultrapure water production according to claim 2, wherein the second The ultrapure water production water treatment device is the ultrapure water production water treatment device according to claim 4 or 5.

  According to the water treatment apparatus for producing ultrapure water according to claim 1, gas or gas-dissolved water is added to water according to the concentration of the substance to be treated, gas component concentration or product concentration. An appropriate amount can be obtained.

  According to the water treatment apparatus for producing ultrapure water according to claims 2 and 3, the amount of oxygen added can be set to an appropriate amount.

  According to the water treatment apparatus for producing ultrapure water according to claims 4 and 5, the amount of hydrogen to be added can be set to an appropriate amount.

  According to the water treatment system for producing ultrapure water according to the sixth aspect, the organic substances and hydrogen peroxide can be sufficiently removed by adding appropriate amounts of oxygen and hydrogen.

1 is a system diagram of a water treatment apparatus for producing ultrapure water and a water treatment system for producing ultrapure water according to an embodiment. It is a systematic diagram of a water treatment apparatus for producing ultrapure water and a water treatment system for producing ultrapure water according to another embodiment.

  Hereinafter, the present invention will be described in more detail. Hereinafter, ultraviolet rays may be described as UV.

First, the TOC component decomposition mechanism by UV irradiation and the H ₂ O ₂ generation suppression mechanism will be described.

  Usually, water is excited by UV irradiation energy, dissociates into H radicals and OH radicals as shown in the following formula, and repeats the reaction of returning to water instantly.

  A part of the dissociated OH radical reacts with the TOC component and contributes to the TOC component oxidative decomposition, but most recombines and returns to water. In order to increase the amount of TOC component decomposition, it is necessary to increase the amount of OH radicals that react with the TOC component.

  When oxygen gas or oxygen-dissolved water is injected on the primary side of UV irradiation as in claims 2 and 3 of the present invention, the dissociated part of the H radicals and the injected oxygen source are combined as follows: A reaction to return to water occurs. At this time, a part of the OH radical generated by the dissociation of water remains, and this OH radical contributes to the oxidative decomposition of the TOC component, and is considered to increase the TOC component decomposition efficiency.

The mechanism of generating H ₂ O ₂ by UV irradiation is considered as follows.

That is, H radicals and OH radicals are generated by UV irradiation, and most of them are recombined to return to water, but H ₂ O ₂ is generated by binding of some OH radicals. At this time, it is considered that H radicals are also bonded to form H ₂ .

  At this time, the reaction formula when a hydrogen source is injected on the primary side of UV irradiation is shown below.

In this reaction, a part of the OH radicals generated by the dissociation of water is combined with the injected H ₂ and returns to water, so that the amount of H ₂ O ₂ produced is thought to decrease.

  FIG. 1 is an explanatory view of a water treatment apparatus for producing ultrapure water according to embodiments of claims 2 and 3 in which the TOC component removal effect is enhanced by oxygen injection.

  Raw water for the production of ultrapure water is stored in the storage tank 2, supplied through a supply pipe 3 and a supply pump 4, and after oxygen is added by an oxygen supply device 5, a UV irradiation device 6 and a membrane deaeration device 7. Each of the ion exchange device 8 and the ultrafiltration device 9 is treated to form ultrapure water, which is supplied to the use point. Then, the ultrapure water not used at the use point is returned to the storage tank 2 via the ultrapure water return pipe 10. Pure water is supplied to the storage tank 2 through the supply pipe 1 for the amount of water used at the use point.

  The oxygen supply device 5 may be one that injects oxygen gas or one that injects oxygen water, but the oxygen injection amount is easier to control in the type in which oxygen water is injected. Yes, it is preferable.

  A part of the water on the primary side of the UV irradiation device 6 before oxygen is added by the oxygen supply device 5 is adjusted in flow rate by the sampling valve 12 from the sampling pipe 11 and sent to the dissolved oxygen meter 13 and the TOC meter 14. . There are no particular restrictions on the dissolved oxygen meter 13 and the TOC meter 14.

  In this embodiment, a part of the treated water from the UV irradiation apparatus 6 is introduced into the dissolved oxygen meter 13 and the TOC meter 14 via the sampling pipe 15 and the flow rate adjusting valve 16, and the dissolved oxygen concentration in the UV treated water and Measure TOC concentration. Further, a part of the ultrapure water that has passed through the ultrafiltration device 9 is introduced into the dissolved oxygen meter 13 and the TOC meter 14 via the sampling pipe 17 and the flow rate adjusting valve 18, and the oxygen concentration and the TOC concentration in the ultrapure water. Measure.

  In this embodiment, the amount of oxygen from the oxygen supply device 5 is controlled based on the signal from the dissolved oxygen meter 13 in accordance with the TOC concentration behavior on the primary side of the UV irradiation device 6. Specifically, for example, the oxygen supply device 5 is controlled so that the dissolved oxygen concentration in the effluent from the UV irradiation device 6 is about 0.5 to 50 ppb.

The amount of oxygen injection is not general because it depends on the system configuration or the like, but unreacted oxygen or oxygen generated by the decomposition of the increased amount of H ₂ O ₂ by injecting oxygen is used as the membrane deaerator 18 in the subsequent stage. However, it is limited to the range that does not affect the dissolved oxygen concentration at the system outlet. The injection amount is preferably such that the dissolved oxygen concentration in the effluent from the UV irradiation apparatus 6 is about 0.5 to 50 ppb, for example, about 10 ppb, but the effect is expected even at about 1 ppb.

  FIG. 2 is a system diagram of the water treatment apparatus for producing ultrapure water according to claims 4 and 5, wherein hydrogen peroxide is removed by hydrogen injection.

  In this embodiment, hydrogen is added from the hydrogen supply device 20 to the pure water sent from the pump 4 to the UV irradiation device 6. The hydrogen may be a gas or hydrogen-dissolved water, but hydrogen-dissolved water is preferable because the injection amount can be easily controlled.

  In this embodiment, a part of the effluent water from the UV irradiation device 6 is sent to the dissolved hydrogen meter 21 and the dissolved hydrogen peroxide meter 22 through the sampling pipe 15 and the flow rate adjusting valve 16, and the dissolved hydrogen concentration and dissolved peroxidation. The hydrogen concentration is measured.

  Based on the measured values of the dissolved hydrogen meter 21 and the dissolved hydrogen peroxide meter 22, the amount of hydrogen injected from the hydrogen supply device 20 is controlled. This control is preferably performed so that the hydrogen concentration in the dissolved hydrogen meter 21 is 1 to 50 ppb, particularly 2 to 10 ppb.

  Other configurations and operations in FIG. 2 are the same as those in FIG. 1, and the same reference numerals denote the same parts.

  In the present invention, the effluent water from the ultrafiltration device 9 of the water treatment device for producing ultrapure water shown in FIG. 1 is supplied to the device shown in FIG. 2, and hydrogenated UV irradiation treatment is performed to produce ultrapure water. You may do it.

  Hereinafter, examples and comparative examples will be described.

Example 1
The system shown in FIG. 1 was operated under the following conditions.

TOC concentration in make-up water ... 9ppb
Dissolved oxygen concentration in make-up water ... 1.5ppb
Low pressure UV lamp ... Nippon Photo Science Co., Ltd. Low pressure UV lamp Oxygen supply device ... Kurita Kogyo Co., Ltd. oxygen water supply device TOC meter ... Seaverse Seaverse 500RL
Dissolved oxygen meter ... Hack Ultra Analytics Japan's dissolved oxygen meter model 3610
Amount of water supplied from the pump 4 ... 6 m ³ / h
Ultrapure water required oxygen concentration: 5 ppb or less Ultrapure water required TOC concentration: 3 ppb or less In this Example 1, the dissolved oxygen meter 13 measured the dissolved oxygen concentration in the pump 4 discharge water, and based on this measured value, The injection amount from the oxygen supply device 5 was controlled, and the dissolved oxygen concentration on the primary side of the UV irradiation device was increased by 1 ppb. The dissolved oxygen concentration on the primary side of the UV irradiation apparatus was 1 ppb.

  As a result of oxygen injection, when the TOC concentration on the primary side of the UV irradiation apparatus was 5 ppb, the TOC concentration in the ultrapure water fed to the use point was 1 ppb, and the dissolved oxygen concentration was 1 ppb or less.

Comparative Example 1
After the operation of Example 1 was continued, the oxygen injection was stopped from the oxygen supply device 5 and the operation of the comparative example was performed. From the time when the oxygen injection was stopped, the TOC concentration in the ultrapure water supplied to the use point began to increase, and finally the TOC concentration in the ultrapure water increased to 4 ppb.

Example 2
The system shown in FIG. 2 was operated under the following conditions. Other conditions are the same as those in the first embodiment.

Hydrogen supply device ... Hydrogen water supply device manufactured by Kurita Kogyo Co., Ltd. Dissolved hydrogen meter ... Dissolved hydrogen meter model 3600 manufactured by Hack Ultra Analytics Japan
Dissolved hydrogen peroxide meter ... Hydrogen peroxide monitor manufactured by Kurita Kogyo Co., Ltd. Dissolved hydrogen concentration in pure water from storage tank 2 ... 0 ppb
Dissolved hydrogen peroxide concentration in pure water from storage tank 2 ... 0 ppb
Hydrogen-dissolved water was added from the hydrogen supply device 20 so that the detected value of the dissolved hydrogen meter 21 was 10 ppb. As a result, the hydrogen peroxide concentration detected by the hydrogen peroxide meter 22 was 5 ppb.

Comparative Example 2
After the operation of Example 2 was continued, the hydrogen addition from the hydrogen supply device 20 was stopped. As a result, the detection value of the hydrogen peroxide meter 22 increased to 20 ppb.

As is clear from the above examples and comparative examples, when the TOC is decomposed to a low concentration (5 ppb or less) by a UV irradiation apparatus in a low dissolved oxygen (5 ppb or less) state, according to the present invention, the UV irradiation is performed more than the conventional technique. The output can be lowered. In addition, the H ₂ O ₂ concentration generated with UV irradiation can be reduced.

5 Oxygen supply device 6 Ultraviolet irradiation device 7 Membrane degassing device 8 Ion exchange device 9 Ultrafiltration device 20 Hydrogen supply device

The present invention relates to the ultrapure water production water treatment equipment provided with a ultraviolet irradiation device.

  In general, an apparatus for producing ultrapure water used for cleaning silicon wafers or the like is generally used in a primary pure water system into which treated water of a pretreatment system is introduced and a secondary in which treated water of a primary pure water system is introduced. And a pure water system (subsystem). The primary pure water system is composed of an ion exchange device, reverse osmosis membrane device, deaeration device, ultraviolet sterilization device, etc., and most of impurities such as fine particles, ionic components, organic substances, colloidal components contained in the water to be treated. To be removed. The secondary pure water system includes a treated water introduction tank, an ultraviolet oxidizer, a cartridge polisher (non-regenerative mixed bed ion exchanger), an ultrafiltration membrane device, and the like of the primary pure water system. It removes a trace amount of impurities remaining in the treated water of the system (for example, JP-A-9-253639).

  In JP-A-9-253639, after removing dissolved nitrogen from pure water from a primary pure water system by a degassing device, oxygen or ozone is added, and then supplied to an ultraviolet irradiation device to oxidize TOC. It is described that the decomposition efficiency is improved. In paragraph 0015 of the same publication, if dissolved oxygen is present in the water treated by the ultraviolet irradiation apparatus, it is described that hydroxyl radicals and hydrogen peroxide are generated by the ultraviolet irradiation, and the TOC decomposition efficiency is improved. .

JP-A-9-253639

  The present invention has a gas component addition means for adding gas or gas-dissolved water to the water to be treated, and an ultraviolet irradiation device for irradiating the water from the gas component addition means with ultraviolet rays to decompose the material to be treated. An object of the present invention is to make an appropriate amount of gas component addition in a water treatment apparatus for producing ultrapure water.

The present invention, in one aspect thereof, and to provide ultrapure water production water treatment equipment which can sufficiently decompose the organic matter (TOC component) in proper oxygenation.

The water treatment apparatus for producing ultrapure water according to the present invention (Claim 1) includes a gas component addition means for adding gas or gas-dissolved water to the water to be treated, and water from the gas component addition means by irradiating with ultraviolet rays to In the water treatment apparatus for producing ultrapure water having an ultraviolet irradiation device for decomposing the material to be treated, the material to be treated is an organic substance, and the gas is oxygen, provided at the front and rear stages of the ultraviolet irradiation device. and the dissolved oxygen concentration Dohaka constant means, is characterized in that and a control means for controlling the amount of gas or gas-dissolved water by the gas component addition means based on the measurement result of the measuring means .

It ultrapure water production water treatment apparatus according to claim 2, in claim 1, before Symbol measuring means is for measuring the dissolved oxygen concentration in the stage after the preceding stage and the ultraviolet irradiation apparatus of the gas component addition means It is characterized by.

The water treatment apparatus for producing ultrapure water according to claim 3 is the water treatment apparatus according to claim 1 or 2 , further comprising means for measuring the concentration of dissolved organic matter in water at least one of the front stage of the gas component addition means and the rear stage of the ultraviolet irradiation device. It is characterized by having .

According to an ultrapure water production water treatment apparatus of claim 1, the gas or gas dissolved water so added to water, it can be an appropriate amount of the amount of oxygen in response to dissolved oxygen concentration.

1 is a system diagram of a water treatment apparatus for producing ultrapure water and a water treatment system for producing ultrapure water according to an embodiment. It is a systematic diagram of a water treatment device for ultrapure water production and a water treatment system for ultrapure water production according to a reference example .

  Hereinafter, the present invention will be described in more detail. Hereinafter, ultraviolet rays may be described as UV.

First, the TOC component decomposition mechanism by UV irradiation and the H ₂ O ₂ generation suppression mechanism will be described.

  Usually, water is excited by UV irradiation energy, dissociates into H radicals and OH radicals as shown in the following formula, and repeats the reaction of returning to water instantly.

  A part of the dissociated OH radical reacts with the TOC component and contributes to the TOC component oxidative decomposition, but most recombines and returns to water. In order to increase the amount of TOC component decomposition, it is necessary to increase the amount of OH radicals that react with the TOC component.

If this onset bright oxygen gas or oxygen-dissolved water in the primary side of the UV irradiation as has been injected, as follows, source of oxygen injected as part of H radicals dissociated binds returns to the water reaction Happens. At this time, a part of the OH radical generated by the dissociation of water remains, and this OH radical contributes to the oxidative decomposition of the TOC component, and is considered to increase the TOC component decomposition efficiency.

The mechanism of generating H ₂ O ₂ by UV irradiation is considered as follows.

That is, H radicals and OH radicals are generated by UV irradiation, and most of them are recombined to return to water, but H ₂ O ₂ is generated by binding of some OH radicals. At this time, it is considered that H radicals are also bonded to form H ₂ .

  At this time, the reaction formula when a hydrogen source is injected on the primary side of UV irradiation is shown below.

In this reaction, a part of the OH radicals generated by the dissociation of water is combined with the injected H ₂ and returns to water, so that the amount of H ₂ O ₂ produced is thought to decrease.

Figure 1 is an illustration of the ultrapure water production water treatment apparatus according to implementation in a form so as to increase the TOC component removing effect by oxygen implantation.

  Raw water for the production of ultrapure water is stored in the storage tank 2, supplied through a supply pipe 3 and a supply pump 4, and after oxygen is added by an oxygen supply device 5, a UV irradiation device 6 and a membrane deaeration device 7. Each of the ion exchange device 8 and the ultrafiltration device 9 is treated to form ultrapure water, which is supplied to the use point. Then, the ultrapure water not used at the use point is returned to the storage tank 2 via the ultrapure water return pipe 10. Pure water is supplied to the storage tank 2 through the supply pipe 1 for the amount of water used at the use point.

  The oxygen supply device 5 may be one that injects oxygen gas or one that injects oxygen water, but the oxygen injection amount is easier to control in the type in which oxygen water is injected. Yes, it is preferable.

  A part of the water on the primary side of the UV irradiation device 6 before oxygen is added by the oxygen supply device 5 is adjusted in flow rate by the sampling valve 12 from the sampling pipe 11 and sent to the dissolved oxygen meter 13 and the TOC meter 14. . There are no particular restrictions on the dissolved oxygen meter 13 and the TOC meter 14.

  In this embodiment, a part of the treated water from the UV irradiation apparatus 6 is introduced into the dissolved oxygen meter 13 and the TOC meter 14 via the sampling pipe 15 and the flow rate adjusting valve 16, and the dissolved oxygen concentration in the UV treated water and Measure TOC concentration. Further, a part of the ultrapure water that has passed through the ultrafiltration device 9 is introduced into the dissolved oxygen meter 13 and the TOC meter 14 via the sampling pipe 17 and the flow rate adjusting valve 18, and the oxygen concentration and the TOC concentration in the ultrapure water. Measure.

  In this embodiment, the amount of oxygen from the oxygen supply device 5 is controlled based on the signal from the dissolved oxygen meter 13 in accordance with the TOC concentration behavior on the primary side of the UV irradiation device 6. Specifically, for example, the oxygen supply device 5 is controlled so that the dissolved oxygen concentration in the effluent from the UV irradiation device 6 is about 0.5 to 50 ppb.

The amount of oxygen injection is not general because it depends on the system configuration or the like, but unreacted oxygen or oxygen generated by the decomposition of the increased amount of H ₂ O ₂ by injecting oxygen is used as the membrane deaerator 18 in the subsequent stage. However, it is limited to the range that does not affect the dissolved oxygen concentration at the system outlet. The injection amount is preferably such that the dissolved oxygen concentration in the effluent from the UV irradiation apparatus 6 is about 0.5 to 50 ppb, for example, about 10 ppb, but the effect is expected even at about 1 ppb.

FIG. 2 is a system diagram of a water treatment apparatus for producing ultrapure water in which hydrogen peroxide is removed by hydrogen injection.

In this reference example , hydrogen is added from the hydrogen supply device 20 to the pure water sent from the pump 4 to the UV irradiation device 6. The hydrogen may be a gas or hydrogen-dissolved water, but hydrogen-dissolved water is preferable because the injection amount can be easily controlled.

In this reference example , a part of the effluent from the UV irradiation device 6 is sent to the dissolved hydrogen meter 21 and the dissolved hydrogen peroxide meter 22 via the sampling pipe 15 and the flow rate adjusting valve 16, and the dissolved hydrogen concentration and dissolved hydrogen peroxide are measured. The concentration is measured.

  Based on the measured values of the dissolved hydrogen meter 21 and the dissolved hydrogen peroxide meter 22, the amount of hydrogen injected from the hydrogen supply device 20 is controlled. This control is preferably performed so that the hydrogen concentration in the dissolved hydrogen meter 21 is 1 to 50 ppb, particularly 2 to 10 ppb.

  Other configurations and operations in FIG. 2 are the same as those in FIG. 1, and the same reference numerals denote the same parts.

  In the present invention, the effluent water from the ultrafiltration device 9 of the water treatment device for producing ultrapure water shown in FIG. 1 is supplied to the device shown in FIG. 2, and hydrogenated UV irradiation treatment is performed to produce ultrapure water. You may do it.

  Hereinafter, examples and comparative examples will be described.

Example 1
The system shown in FIG. 1 was operated under the following conditions.

TOC concentration in make-up water ... 9ppb
Dissolved oxygen concentration in make-up water ... 1.5ppb
Low pressure UV lamp ... Nippon Photo Science Co., Ltd. Low pressure UV lamp Oxygen supply device ... Kurita Kogyo Co., Ltd. oxygen water supply device TOC meter ... Seaverse Seaverse 500RL
Dissolved oxygen meter ... Hack Ultra Analytics Japan's dissolved oxygen meter model 3610
Amount of water supplied from the pump 4 ... 6 m ³ / h
Ultrapure water required oxygen concentration: 5 ppb or less Ultrapure water required TOC concentration: 3 ppb or less In this Example 1, the dissolved oxygen meter 13 measured the dissolved oxygen concentration in the pump 4 discharge water, and based on this measured value, The injection amount from the oxygen supply device 5 was controlled, and the dissolved oxygen concentration on the primary side of the UV irradiation device was increased by 1 ppb. The dissolved oxygen concentration on the primary side of the UV irradiation apparatus was 1 ppb.

  As a result of oxygen injection, when the TOC concentration on the primary side of the UV irradiation apparatus was 5 ppb, the TOC concentration in the ultrapure water fed to the use point was 1 ppb, and the dissolved oxygen concentration was 1 ppb or less.

Comparative Example 1
After the operation of Example 1 was continued, the oxygen injection was stopped from the oxygen supply device 5 and the operation of the comparative example was performed. From the time when the oxygen injection was stopped, the TOC concentration in the ultrapure water supplied to the use point began to increase, and finally the TOC concentration in the ultrapure water increased to 4 ppb.

Reference example 1
The system shown in FIG. 2 was operated under the following conditions. Other conditions are the same as those in the first embodiment.

Hydrogen supply device ... Hydrogen water supply device manufactured by Kurita Kogyo Co., Ltd. Dissolved hydrogen meter ... Dissolved hydrogen meter model 3600 manufactured by Hack Ultra Analytics Japan
Dissolved hydrogen peroxide meter ... Hydrogen peroxide monitor manufactured by Kurita Kogyo Co., Ltd. Dissolved hydrogen concentration in pure water from storage tank 2 ... 0 ppb
Dissolved hydrogen peroxide concentration in pure water from storage tank 2 ... 0 ppb
Hydrogen-dissolved water was added from the hydrogen supply device 20 so that the detected value of the dissolved hydrogen meter 21 was 10 ppb. As a result, the hydrogen peroxide concentration detected by the hydrogen peroxide meter 22 was 5 ppb.

Comparative Example 2
After the operation of Reference Example 1 was continued, hydrogen addition from the hydrogen supply device 20 was stopped. As a result, the detection value of the hydrogen peroxide meter 22 increased to 20 ppb.

As is clear from the above examples and comparative examples, when the TOC is decomposed to a low concentration (5 ppb or less) by a UV irradiation apparatus in a low dissolved oxygen (5 ppb or less) state, according to the present invention, the UV irradiation is performed more than the conventional technique. The output can be lowered. In addition, the H ₂ O ₂ concentration generated with UV irradiation can be reduced.

5 Oxygen supply device 6 Ultraviolet irradiation device 7 Membrane degassing device 8 Ion exchange device 9 Ultrafiltration device 20 Hydrogen supply device

Claims (6)

Gas component addition means for adding gas or gas-dissolved water to the water to be treated;
In a water treatment apparatus for producing ultrapure water having an ultraviolet irradiation apparatus for irradiating water from the gas component addition means with ultraviolet rays to decompose a substance to be treated in water,
A measuring means for measuring the concentration of the substance to be treated, the gas component concentration or the product concentration in the water provided in the front stage or the rear stage of the ultraviolet irradiation device;
Control means for controlling the amount of gas or gas dissolved water added by the gas component addition means based on the measurement result of the measurement means;
A water treatment apparatus for producing ultrapure water, comprising: In claim 1,
The substance to be treated is an organic substance,
The gas is oxygen;
The water treatment apparatus for producing ultrapure water, wherein the measurement means measures the dissolved oxygen concentration at least one of a front stage of the gas component addition means and a rear stage of the ultraviolet irradiation device. In claim 1,
The substance to be treated is an organic substance,
The gas is oxygen;
The water treatment apparatus for producing ultrapure water, wherein the measuring means measures dissolved oxygen concentration and dissolved organic substance concentration at least one of the former stage of the adding means and the latter stage of the ultraviolet irradiation device. In claim 1,
The gas is hydrogen;
The substance to be treated in the treated water is hydrogen peroxide,
The said measurement means measures the dissolved hydrogen concentration in the water from the said ultraviolet irradiation apparatus, The water treatment apparatus for ultrapure water manufacture characterized by the above-mentioned. In claim 1,
The gas is hydrogen;
The substance to be treated in the treated water is hydrogen peroxide,
The said measurement means measures the dissolved hydrogen peroxide density | concentration in the water from the said ultraviolet irradiation apparatus, The water treatment apparatus for ultrapure water manufacture characterized by the above-mentioned. Ultrapure water production water comprising a first ultrapure water production water treatment device and a second ultrapure water production water treatment device for treating treated water from the first ultrapure water production water treatment device In the processing system,
The first water treatment apparatus for producing ultrapure water is the water treatment apparatus for producing ultrapure water according to claim 2 or 3,
The water treatment apparatus for producing ultrapure water according to claim 4 or 5, wherein the second water treatment apparatus for producing ultrapure water is the water treatment apparatus for producing ultrapure water.

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