Water treatment apparatus and water treatment method

Abstract

To provide a water treatment apparatus capable of stably obtaining treated water without increasing a load on particulate capture means such as a membrane separation apparatus.SOLUTION: A water treatment apparatus 1 includes: a supply line 2 for treated water W; a tank 3 for storing the treated water W; a pump 4; ion removal means 5; first particulate capture means 6; a particulate meter 7 arranged at a front stage of these; and three-way valves 8. One of the three-way valves 8 is a treatment flow path 9, which leads directly to a water treatment element in a latter stage. The other of the three-way valve 8 is a particulate removal channel 10. The particulate removal channel 10 is provided with second particulate capture means 11, and the treated water treated by the second particulate capture means 11 is merged with the treatment channel 9 through a confluence channel 12. The three-way valve 8 can be switched between the treatment channel 9 side and the particulate removal channel 10 side based on measured values of the particulate meter 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water treatment apparatus and a water treatment method for removing fine particles contained in liquid in a pure water or ultrapure water production process, or in an electronic component manufacturing process or a semiconductor cleaning process. [Background technology]

[0002] In ultrapure water production and supply systems used in semiconductor manufacturing processes, etc., a cross-flow type ultrafiltration membrane (UF membrane) device for removing fine particles is installed at the end of the subsystem, and nanometer-sized fine particles are removed by operating at a water recovery rate of 90-99%. Also, it is being considered to install a mini subsystem as a point-of-use polisher immediately before the cleaning machine for cleaning semiconductor and electronic materials, and to install a UF membrane device for removing fine particles at the final stage, or to install a UF membrane for removing fine particles immediately before the nozzle in the cleaning machine at the point-of-use, in order to highly remove even smaller fine particles.

[0003] Conventionally, in ultrapure water production apparatuses, the following techniques have been proposed as techniques for removing impurities such as fine particles from water to a high degree to increase the purity.

[0004] Patent Document 1 describes a water treatment method in which, for a particle measuring section and a switching line provided between a dissolving membrane module and a particle capture section, water is discharged without passing through the particle capture section depending on the particle count.

[0005] Furthermore, Patent Document 2 describes a water treatment method in which a particle removal device that removes particles from a liquid has a plurality of particle capture means with different characteristics or physical properties installed in parallel, and switches between the particle capture means through which the liquid passes depending on the water quality of the liquid. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2019 / 181339 publication [Patent Document 2] JP 2022-126354 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the water treatment method of Patent Document 1, if the fine particles in the water to be treated cannot be completely removed and leak, causing an abnormal value to be measured, the entire amount of the water is discharged, which stops the supply of the treated water. Furthermore, there is a problem that further energy and costs are required to reuse the discharged treated water as treated water again, which is not preferable from the viewpoint of energy conservation.

[0008] In addition, in the water treatment method described in Patent Document 2, the water to be treated is treated by passing it through in parallel, so if the particulate load is very large, there is a risk that the membrane's lifespan and performance will be reduced, and therefore there is a problem that this is not sufficient as a method to respond to abnormalities in the particulate count in the treated water.

[0009] The present invention has been made in consideration of the above problems, and aims to provide a water treatment device that can stably obtain treated water without increasing the load on a particle capture means such as a membrane separation device by adding a particle removal step according to the water quality of the particles in the water to be treated. Another aim of the present invention is to provide a water treatment method that can stably obtain treated water without increasing the load on a particle capture means such as a membrane separation device by adding a particle removal step according to the water quality of the particles in the water to be treated. [Means for solving the problem]

[0010] In view of the above-mentioned object, the present invention first provides a water treatment device having a tank, a particulate capture means or an ion removal means, and a particulate measurement means, the water treatment device having a flow path switching means upstream of the tank, the particulate capture means or the ion removal section, the flow path switching means being switchable between a treatment flow path communicating with the tank, the particulate capture means or the ion removal section, and a particulate removal flow path equipped with an auxiliary particulate capture means, the particulate removal flow path passing through the auxiliary particulate capture means and merging with the treatment flow path downstream of the flow path switching means (Invention 1).

[0011] According to this invention (Invention 1), depending on the water quality in terms of fine particles of the water to be treated passing through, it is possible to remove fine particles from the water to be treated using an auxiliary fine particle capture means in the upstream of the fine particle tank, fine particle capture means or ion removal means, and then pass the water through the downstream of the water treatment device. This reduces the fine particle load on the components of the water treatment device, such as the fine particle capture means and ion removal means, and makes it possible to stably produce treated water while maintaining their performance.

[0012] In the above invention (Invention 1), it is preferable that the particulate measuring means is provided upstream of the tank, the particulate capturing means or the ion removing means (Invention 2).

[0013] According to this invention (Invention 2), the fine particles in the water to be treated are measured upstream of the tank, fine particle capture means or ion removal means, and depending on the water quality at the fine particle level of the water to be treated passing through, the fine particles are removed using an auxiliary fine particle capture means before the water is passed through. This effectively reduces the fine particle load on the components of the water treatment device, such as the fine particle capture means and ion removal means, and makes it possible to stably produce treated water while maintaining their performance.

[0014] In the above invention (Invention 2), it is preferable that the flow path switching means is provided downstream of the particle measuring means (Invention 3).

[0015] According to this invention (Invention 3), by providing a flow path switching means downstream of the particle measuring means, switching can be made immediately after the particle measuring means depending on the water quality at the particle surface measured by the particle measuring means. This effectively reduces the particle load on components of the water treatment device such as the particle capture means and ion removal means, and enables stable production of treated water while maintaining their performance.

[0016] In the above inventions (Inventions 1 to 3), it is preferable to have a control means for switching the flow path switching means between the processing flow path and the particle removal flow path based on measurement information from the particle measuring means (Invention 4).

[0017] According to this invention (Invention 4), the treatment flow path and the particle removal flow path can be switched automatically based on the measurement value of the particle measurement means, so that water treatment with reduced particle load can be performed stably.

[0018] Secondly, the present invention provides a water treatment method for treating water to be treated in a water treatment device having a tank, a particulate capture means or an ion removal means, and a particle measurement means, and based on the measurement value of the particulate measurement means, the water to be treated is either supplied to the tank, the particulate capture means or the ion removal section, or passed through an auxiliary particulate capture means and then supplied to the tank, the particulate capture means or the ion removal section (Invention 5).

[0019] According to this invention (Invention 5), depending on the water quality in terms of fine particles of the water to be treated passing through, it is possible to switch between treating the water as is or removing fine particles using a fine particle tank for the water to be treated, a fine particle capture means, or an auxiliary fine particle capture means upstream of the ion removal means, and then passing the water through the water treatment device. This reduces the fine particle load on the components of the water treatment device, such as the fine particle capture means and ion removal means, and makes it possible to stably produce treated water while maintaining their performance.

[0020] In the above invention (Invention 5), it is preferable that the particulate measuring means is provided upstream of the tank, the particulate capturing means or the ion removing means (Invention 6).

[0021] According to this invention (Invention 6), the fine particles in the water to be treated are measured upstream of the fine particle capture means or the ion removal means, and depending on the water quality at the fine particle level of the water to be treated passing through, the fine particles are removed using an auxiliary fine particle capture means before the water is passed through. This effectively reduces the fine particle load on the components of the water treatment device, such as the fine particle capture means and the ion removal means, and enables the stable production of treated water while maintaining their performance. Effect of the Invention

[0022] According to the water treatment device of the present invention, in a water treatment device having a flow path switching means upstream of either the tank, the particulate capture means or the ion removal section, the flow path switching means can switch between a treatment flow path connected to the tank, the particulate capture means or the ion removal section, and a particulate removal flow path equipped with an auxiliary particulate capture means, and the particulate removal flow path merges with the treatment flow path downstream of the flow path switching means via the auxiliary particulate capture means, thereby reducing the particulate load on the components of the water treatment device such as the particulate capture means and ion removal means, and enabling stable production of treated water while maintaining their performance. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing a water treatment device according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a schematic diagram showing a water treatment device according to a second embodiment of the present invention. [Diagram 3] FIG. 4 is a schematic diagram showing a water treatment device according to a third embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram showing a water treatment device used in Examples 1 and 2 and Comparative Examples 1 and 2. [Diagram 5] 1 is a graph showing the change over time in the number of fine particles in treated water in Example 1 and Comparative Example 1. [Figure 6]1 is a graph showing the transition of the number of fine particles in treated water in Example 2 and Comparative Example 2. [Figure 7] FIG. 2 is a schematic diagram showing a water treatment device used in Examples 3 and 4 and Comparative Examples 3 and 4. [Figure 8] 1 is a graph showing the transition of the number of fine particles in treated water in Example 3 and Comparative Example 3. [Figure 9] 1 is a graph showing the transition of the number of fine particles in the treated water in Example 4 and Comparative Example 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The water treatment device of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] [First embodiment] <Water treatment equipment> FIG. 1 shows a water treatment device according to a first embodiment of the present invention. In FIG. 1, the water treatment device 1 has a supply line 2 for water W to be treated, a tank 3 for storing the water W to be treated, a pump 4, an ion removal means 5, a first fine particle capture means 6, a fine particle meter 7 as a fine particle measurement means arranged in the preceding stage, and a three-way valve 8 as a flow path switching means arranged in the subsequent stage of the fine particle meter 7. One side of the three-way valve 8 is a treatment flow path 9, which is directly connected to the tank 3. The other side of the three-way valve 8 is a fine particle removal flow path 10, and the fine particle removal flow path 10 is provided with a second fine particle capture means 11 as an auxiliary fine particle capture means. The water to be treated that has been treated by the second fine particle capture means 11 flows into the treatment flow path 9 from a junction flow path 12. In this embodiment, the measurement value of the fine particle meter 7 can be transmitted to a control means such as a personal computer (not shown), and the control means can switch the three-way valve 8 between the treatment flow path 9 side and the fine particle removal flow path 10 side based on the measurement value. In addition, 13 is a wastewater channel.

[0026] (Ion Removal Means) In this embodiment, the ion removing means 5 is not particularly limited, and an ion exchange resin, an ion exchange filter, an electric deionization device, or the like can be used, with the ion exchange resin being the most commonly used.

[0027] The ion exchange resin may be either a gel type or a porous type ion exchange resin (anion exchange resin, cation exchange resin). As the ion exchange resin, the UP series manufactured by Dow Chemical Company, the Diaion series manufactured by Mitsubishi Chemical Corporation, the KR series manufactured by Kurita Water Industries Ltd., etc. may be used. Such anion exchange resin and cation exchange resin may be used alone, or a mixture or laminate of both resins may be used. For example, it is preferable to use a mixture or laminate of anion exchange resin:cation exchange resin=30:70 to 70:30 (volume ratio).

[0028] (Particle capture means) There are no particular limitations on the fine particle capturing means 6, 11, and they may be selected according to the fine particles to be removed contained in the water to be treated W, and separation membranes such as porous membranes, size exclusion membranes, and charged membranes can be used.

[0029] As the porous membrane, any of a polymer membrane, an inorganic membrane, and a metal membrane can be used.

[0030] As the polymer membrane, materials such as polyolefins such as polyethylene and polypropylene, polyethers such as polyethylene oxide and polypropylene oxide, fluororesins such as PTFE, CTFE, PFA, and polyvinylidene fluoride (PVDF), halogenated polyolefins such as polyvinyl chloride, polyamides such as nylon-6 and nylon-66, urea resins, phenolic resins, melamine resins, polystyrene, cellulose, cellulose acetate, cellulose nitrate, polyether ketone, polyether ketone ketone, polyether ether ketone, polysulfone, polyether sulfone, polyimide, polyether imide, polyamide imide, polybenzimidazole, polycarbonate, polyethylene terephthalate, polyarylsulfone, polybutylene terephthalate, polyphenylene sulfide, polyacrylonitrile, polyether nitrile, polyvinyl alcohol, and copolymers thereof can be used, but are not limited to these. There is no particular limitation to one type of material, and multiple materials may be used in combination as necessary. Other polymers such as polyolefins and polyethers may be mixed with charged or conductive polymers. As the inorganic film, a metal oxide film such as alumina or zirconia can be used.

[0031] A size exclusion membrane is a polymer membrane in which functional groups have not been intentionally introduced or which has not been intentionally modified to make it electrically charged, and its purpose is to exclude fine particles larger than a certain particle size.

[0032] A charged membrane is a membrane in which functional groups are intentionally introduced into a polymer membrane, and is capable of favorably adsorbing charged particles. Examples of the functional groups to be introduced include, but are not limited to, sulfonic acid groups, phosphoric acid groups, phosphonic acid groups, phosphinic acid groups, carboxylic acid groups, hydroxyl groups, phenol groups, quaternary ammonium groups, primary to tertiary amine groups, pyridine groups, and amide groups. These functional groups may be not only H-type or OH-type, but also salt types such as Na.

[0033] There is no particular restriction on the form of the separation membrane as described above, and a suitable one may be used depending on the application, such as a hollow fiber membrane, a flat membrane, or a fiber. For example, a hollow fiber membrane is usually used as a terminal membrane module for removing fine particles in a unit of an ultrapure water system. On the other hand, a pleated flat membrane is often used as a filter to be installed in a process cleaner.

[0034] (Method of measuring fine particles) The particle counter 7 serving as the particle measuring means can be of a light scattering type, a nebulizer+CPC+light scattering type, an ultrasonic type, or the like.

[0035] Examples of light scattering type particle counters include Hslis M50e, Ultra DI50, Ultra Chem 40, Ultra DI20, Chem20, and KL19F manufactured by Spectris; KL-30AX, KL-30B, KL-30, KS-19F, KS-17B, KS-18F, KS-18FX, KS-16 / KS16F, KS-41A, KS-41B, KS-42A / 42F, KS-42B / 42BF, KS-42C, KS-42D, and XP-65 manufactured by Rion; and Nanocount 25, Nanocount 30, and Nanocount 50+ manufactured by Lighthouse. Examples of particle counters using a nebulizer, CPC, and light scattering method include Scanning TPC model 9010-03 and Scanning TPC model 9010 manufactured by Kanomax. Examples of ultrasonic particle counters include PS10 and PS20 manufactured by Uncopiers. These particle counters are merely examples and are not intended to be limiting.

[0036] <Treated water> In this embodiment, the water to be treated W to be treated can be any of wastewater, pure water, and ultrapure water, but is particularly suitable for treating ultrapure water.

[0037] Ultrapure water has the following properties: resistivity: 18.1 MΩ cm or more, fine particles: 1000 particles / L or less with a particle size of 50 nm or more, live bacteria: 1 particle / L or less, TOC (Total Organic Carbon): 1 μg / L or less, total silicon: 0.1 μg / L or less, metals: 1 ng / L or less, ions: 10 ng / L or less, hydrogen peroxide: 30 μg / L or less, and water temperature: 25 ± 2°C.

[0038] <Water treatment method> The water treatment method of this embodiment using the water treatment device 1 of this embodiment having the above-mentioned configuration will be described below.

[0039] While the water W to be treated is supplied to the tank 3 from the supply line 2 by a supply means (not shown), the number of particles per unit water volume in the water W to be treated is measured by the particle meter 7. At this time, a reference value for the number of particles per unit water volume is set in advance. If the measured value of the particle meter 7 is equal to or less than the reference value, the control means (not shown) opens the treatment flow path 9 side of the three-way valve 8 and closes the particle removal flow path 10 side, and the water W to be treated is stored in the tank 3 as it is. On the other hand, if the measured value of the particle meter 7 exceeds the reference value, the control means closes the treatment flow path 9 side of the three-way valve 8 and opens the particle removal flow path 10 side. As a result, the water W to be treated has particles auxiliary removed by the second particle capture means 11, and then merges with the treatment flow path 9 from the merge flow path 12 to store the water W to be treated in the tank 3.

[0040] In this way, the tank 3 always stores the treated water W with a reduced number of fine particles, so that by starting the pump 4 and treating the treated water W with the ion removal means 5 and the first fine particle capture means 6, treated water W1 with a reduced number of fine particles and from which ionic impurities have been removed can be produced.

[0041] According to the water treatment method of this embodiment, the ion removal means 5 and the first particle capture means 6 always treat the treated water W in which the number of particles is reduced, and since the load on the particle surface of the ion removal means 5 and the first particle capture means 6 is low, it is possible to produce treated water W1 stably for a long period of time.

[0042] Second Embodiment Next, a water treatment device according to a second embodiment of the present invention will be described with reference to Fig. 2. The water treatment device according to this embodiment basically has the same configuration as that of the first embodiment described above, so the same components are denoted by the same reference numerals and detailed description thereof will be omitted.

[0043] <Water treatment equipment> The water treatment device of the second embodiment has a particle meter 7 as particle measuring means and a three-way valve 8 as flow path switching means, upstream of the ion removal means 5, in the first embodiment described above, and one side of this three-way valve 8 is directly connected to the ion removal means 5. On the other hand, the other side of the three-way valve 8 serves as a particle removal flow path 10, and this particle removal flow path 10 is provided with a second particle capture means 11 as auxiliary particle capture means, and the water to be treated that has been treated by the second particle capture means 11 flows into the treatment flow path 9 from a junction flow path 12.

[0044] <Water treatment method> A water treatment method using the water treatment device 1 of this embodiment having the above-mentioned configuration will be described below.

[0045] The water W to be treated is stored in the tank 3 from the supply line 2 by a supply means (not shown). Next, the pump 4 is started to supply the water W to be treated to the ion removal means 5, while the number of particles per unit water volume in the water W to be treated is measured by the particle meter 7. If the measured value of the particle meter 7 is equal to or less than the reference value, the control means (not shown) opens the treatment flow path 9 side of the three-way valve 8 and closes the particle removal flow path 10 side, and the water W to be treated is directly treated by the ion removal means 5 and the first particle capture means 6. On the other hand, if the measured value of the particle meter 7 exceeds the reference value, the control means (not shown) closes the treatment flow path 9 side of the three-way valve 8 and opens the particle removal flow path 10 side. As a result, the water W to be treated is subjected to auxiliary particle removal by the second particle capture means 11, and then merges with the treatment flow path 9 side from the merge flow path 12, and is then treated by the ion removal means 5 and the first particle capture means 6.

[0046] In this way, the ion removal means 5 and the first microparticle capture means 6 can always treat the treated water W with a reduced number of microparticles, thereby producing treated water W1 with a reduced number of microparticles and from which ionic impurities have been removed.

[0047] According to the water treatment method of this embodiment, the ion removal means 5 and the first particle capture means 6 always treat the treated water W in which the number of particles is reduced, and since the load on the particle surface of the ion removal means 5 and the first particle capture means 6 is low, it is possible to produce treated water W1 stably for a long period of time.

[0048] Third Embodiment Next, a water treatment device according to a thirty-second embodiment of the present invention will be described with reference to Fig. 3. The water treatment device according to this embodiment basically has the same configuration as that of the first embodiment described above, and therefore the same components are designated by the same reference numerals and detailed description thereof will be omitted.

[0049] <Water treatment equipment> The water treatment device of the third embodiment has a particle meter 7 as particle measuring means, and a three-way valve 8 as flow path switching means, upstream of the first particle capture means 6 in the first embodiment described above, and one side of the three-way valve 8 is directly connected to the first particle capture means 6. The other side of the three-way valve 8 is a particle removal flow path 10, and this particle removal flow path 10 is provided with a second particle capture means 11 as auxiliary particle capture means, and the water to be treated that has been treated by the second particle capture means 11 flows into the treatment flow path 9 from a junction flow path 12.

[0050] <Water treatment method> A water treatment method using the water treatment device 1 of this embodiment having the above-mentioned configuration will be described below.

[0051] The water W to be treated is stored in the tank 3 from the supply line 2 by a supply means (not shown). Then, the pump 4 is started to treat the water W to be treated by the ion removal means 5. Next, the water W to be treated treated by the ion removal means 5 is supplied to the first fine particle capture means 6, while the fine particle meter 7 measures the number of fine particles per unit water volume in the water W to be treated. If the measured value of the fine particle meter 7 is equal to or less than the reference value, the control means (not shown) opens the treatment flow path 9 side of the three-way valve 8 and closes the fine particle removal flow path 10 side, and the water W to be treated is directly treated by the first fine particle capture means 6. On the other hand, if the measured value of the fine particle meter 7 exceeds the reference value, the control means (not shown) closes the treatment flow path 9 side of the three-way valve 8 and opens the fine particle removal flow path 10 side. As a result, the water W to be treated is subjected to auxiliary fine particle removal by the second fine particle capture means 11, and then merges with the treatment flow path 9 side from the merge flow path 12, and is then treated by the first fine particle capture means 6.

[0052] In this way, the first particle capture means 6 can always treat the treated water W with a reduced number of particles, thereby producing treated water W1 with a reduced number of particles and from which ionic impurities have been removed.

[0053] According to the water treatment method of this embodiment, the load on the particulate surface of the first particulate capturing means 6 is low, so that it is possible to stably produce treated water W1 for a long period of time.

[0054] The water treatment device of the present invention has been described above with reference to the attached drawings, but the present invention is not limited to the above-described embodiment and can be modified in various ways. For example, the configuration of the water treatment device 1 is not limited to the above-described embodiment, which is composed of the tank 3, the pump 4, and the ion removal means 5, but can be applied to water treatment devices of various configurations. In addition, the second particulate capture means 11 may be of a cartridge type, and the second particulate capture means 11 may be replaced based on the integrated treatment flow rate, etc. EXAMPLES

[0055] The present invention will now be described in further detail with reference to the following specific examples.

[0056] [Example 1 and Comparative Example 1] A test water treatment device shown in Fig. 4 was prepared. In Fig. 4, the test water treatment device 21 includes a supply line 22 for the water W to be treated and a first fine particle capture means 23. A fine particle meter 24 and a three-way valve 25 are provided upstream of the first fine particle capture means 23, and one side of the three-way valve 25 is the treatment flow path 22A, which is directly connected to the first fine particle capture means 23. The other side of the three-way valve 25 is a fine particle removal flow path 27, and a second fine particle capture means 26 is provided in the fine particle removal flow path 27, and the water W to be treated treated by the second fine particle capture means 26 merges with the treatment flow path 22A from the merge flow path 28. In this embodiment, the measurement value of the fine particle meter 24 is transmitted to a personal computer (not shown), and the three-way valve 25 can be switched between the treatment flow path 22A side and the fine particle removal flow path 27 side based on the measurement value. In the test water treatment device 21, the particulate liquid (PW) can be injected from the particulate liquid tank 29 to the supply line 22 via the pump 29A. Also, the particulate water quality of the treated water W1 can be measured by the particulate meter 30.

[0057] The first particle capturing means 23, the second particle capturing means 26, the particle counters 24, 30 and the injected particles were as follows. First particle trapping means 23: particle trapping membrane (ABD1UPWE3EH1 manufactured by Pall Corporation) Second particle trapping means 26: particle trapping membrane (ABD1UPWE3EH1 manufactured by Pall Corporation) Particle size meter 24,30: Online particle size monitor (UDI20 manufactured by PMS) Microparticles: 22 nm silica particles (Sigma-Aldrich)

[0058] In the test water treatment device 21 shown in FIG. 4, ultrapure water (resistivity: 18.1 MΩ·cm or more) was charged with a fine particle concentration of 10 6 The water to be treated W was constantly spiked with a fine particle liquid adjusted to particles / mL, and the water was passed through at a flow rate of 30 m / d.

[0059] The number of particles of Φ20 nm or more per unit volume of the water to be treated W was measured using particle meter 24, and a reference value of 1000 particles / mL of particles of Φ20 nm or more was used. If the reference value was below this reference value, the three-way valve 25 was switched to the treatment flow path 22A side, and if the reference value was exceeded, the three-way valve 25 was switched to the particle removal flow path 27 side to perform water treatment, and the number of particles of Φ20 nm or more in the treated water W1 was measured using particle meter 30. The results are shown in Figure 5. For comparison, the number of particles of Φ20 nm or more in the treated water W1 was measured using particle meter 30 when the water to be treated W was treated without switching using the three-way valve 25 (Comparative Example 1). The results are also shown in Figure 5.

[0060] 5, in Comparative Example 1, in which the three-way valve 25 was not switched regardless of the particulate load of the water to be treated W, the particulates increased rapidly in about 10 days, whereas in Example 1, in which the three-way valve 25 was switched according to the particulate load, the particulate count of the treated water W1 remained at a very low level and did not fluctuate, making it possible to stably supply treated water W1 with high cleanliness. These results demonstrate that the performance of the first particulate capture means 23 can be maintained for a long period of time by switching the three-way valve 25 to pass the water W through the second particulate capture means 26 when the particulate load of the water to be treated W is high.

[0061] [Example 2 and Comparative Example 2] In the first embodiment, the water W to be treated is fed with the fine particle liquid tank 29 at a fine particle injection concentration of 10 8 Water treatment was performed in the same manner, except that the fine particle liquid adjusted to have a concentration of 1000 particles / mL was temporarily spiked. At this time, the number of fine particles of Φ20 nm or more per unit water volume of the water to be treated W was measured by the fine particle meter 24, and the number of fine particles of Φ20 nm or more was set to 1000 particles / mL as a reference value. If the number of fine particles of Φ20 nm or more was below the reference value, the three-way valve 25 was switched to the treatment flow path 22A side, and if the number exceeded the reference value, the three-way valve 25 was switched to the fine particle removal flow path 27 side to perform water treatment, and the number of fine particles of Φ20 nm or more in the treated water W1 was measured by the fine particle meter 30. The results are shown in FIG. 6. For comparison, the number of fine particles of Φ20 nm or more in the treated water W1 was measured by the fine particle meter 30 when the water to be treated W was treated (Comparative Example 2) without switching by the three-way valve 25. The results are also shown in FIG. 6.

[0062] As is clear from Fig. 6, in Comparative Example 2 in which the three-way valve 25 was not switched regardless of the particulate load of the water W to be treated, the particulates in the treated water W1 increased in a timely manner when the particulates were injected at a high concentration, whereas in Example 2 in which the three-way valve 25 was switched according to the particulate load, the particulate value of the treated water W1 did not fluctuate, and treated water W1 with a low particulate count could always be supplied. From these results, it was shown that by switching the three-way valve to pass the water W through the second particulate capture means 26 when the particulate load of the water W to be treated is high, the water quality is not affected even if the water quality in terms of particulates suddenly deteriorates, and treated water W1 with high cleanliness can be stably supplied.

[0063] [Example 3 and Comparative Example 3] A test water treatment device shown in Fig. 7 was prepared. In Fig. 7, the test water treatment device 31 includes a supply line 32 for the water W to be treated and an ion removal means 33. A particle meter 34 and a three-way valve 35 are provided in front of the first particle capture means 33, and one side of the three-way valve 325 is the treatment flow path 32A, which is directly connected to the ion removal means 33. The other side of the three-way valve 35 is the particle removal flow path 37, and a second particle capture means 36 is provided in this particle removal flow path 37, and the water W to be treated treated by the second particle capture means 36 merges with the treatment flow path 22A from the junction flow path 28. In this embodiment, the measurement value of the particle meter 34 is transmitted to a personal computer (not shown), and the three-way valve 35 can be switched between the treatment flow path 32A side and the particle removal flow path 37 side based on this measurement value. In this test water treatment device 31, particulate liquid (PW) can be injected from a particulate liquid tank 39 via a pump 39A into the supply line 32. Also, the particulate water quality of the treated water W1 can be measured by a particulate meter 40.

[0064] The following were used as the ion removing means 33, the particle counters 34, 40, the second particle capturing means 36 and the injected particles. Ion removal means 33: Ion exchange resin column (a 1:1 mixture of gel-type cation resin and anion resin) Particle size monitor 34, 40: Online particle size monitor (UDI20 manufactured by PMS) Second particle trapping means 36: particle trapping membrane (ABD1UPWE3EH1 manufactured by Pall Corporation) Microparticles: 55nm polystyrene latex (Thermofisher)

[0065] In the test water treatment device 31 shown in FIG. 7, ultrapure water (resistivity: 18.1 MΩ·cm or more) was charged with a microparticle liquid having a microparticle concentration of 10 3 The water to be treated W was prepared by constantly spiking a particulate liquid adjusted to particles / mL. The water to be treated W was passed through the ion removal means 33 under the water passing condition of SV=50 / h.

[0066] The number of particles of Φ50 nm or more per unit volume of the water to be treated W was measured using particle meter 34, and a reference value of 100 particles / mL of particles of Φ50 nm or more was used. If the reference value was below this reference value, three-way valve 35 was switched to the treatment flow path 32A side, and if the reference value was exceeded, water treatment was performed by switching to the particle removal flow path 37 side, and the number of particles of Φ50 nm or more in the treated water W1 was measured using particle meter 40. The results are shown in Figure 8. For comparison, the number of particles of Φ50 nm or more in the treated water W1 was measured using particle meter 40 when the water to be treated W was treated without switching using three-way valve 35 (Comparative Example 3). The results are also shown in Figure 8.

[0067] As is clear from Fig. 8, in Comparative Example 3 in which the three-way valve 25 was not switched regardless of the particulate load of the water to be treated W, the particulates increased rapidly in about 10 days, whereas in Example 3 in which the three-way valve 25 was switched according to the particulate load, the particulate count of the treated water W1 did not fluctuate at a very low level, and it was possible to stably supply treated water W1 with high cleanliness. From these results, it was shown that by switching the three-way valve 35 to pass the water W through the second particulate capture means 36 when the particulate load of the water to be treated W is high, excessive load on the main ion removal means 33 can be suppressed and the ion removal means 33 can be operated stably.

[0068] [Example 4 and Comparative Example 4] In the third embodiment, the water W to be treated is treated with the fine particle liquid tank 39 at a fine particle injection concentration of 10 5 The treatment was carried out in the same manner, except that the fine particle liquid adjusted to have a concentration of 100 particles / mL was temporarily spiked. At this time, the number of fine particles of Φ50 nm or more per unit water volume of the water to be treated W was measured by the fine particle meter 34, and the number of fine particles of Φ50 nm or more was set to 100 particles / mL as a reference value. If the number of fine particles of Φ50 nm or more was below the reference value, the three-way valve 35 was switched to the treatment flow path 32A side, and if the number exceeded the reference value, the three-way valve 35 was switched to the fine particle removal flow path 37 side to perform water treatment, and the number of fine particles of Φ50 nm or more in the treated water W1 was measured by the fine particle meter 40. The results are shown in FIG. 9. For comparison, the number of fine particles of Φ50 nm or more in the treated water W1 was continuously measured when the water to be treated W was treated (Comparative Example 4) without switching by the three-way valve 35. The results are also shown in FIG. 9.

[0069] As is clear from Fig. 9, in Comparative Example 4, in which the three-way valve 35 was not switched regardless of the particulate load of the water W to be treated, the particulates in the treated water W1 increased in a timely manner when the particulates were injected at a high concentration, whereas in Example 4, in which the three-way valve 35 was switched according to the particulate load, the particulate value of the treated water W1 did not fluctuate, and treated water W1 with a low particulate count could always be supplied. From these results, it was shown that by switching the three-way valve 35 to pass the water W through the second particulate capture means 36 when the particulate load of the water W to be treated is high, the water quality is not affected even if the water quality in terms of particulates suddenly deteriorates, and treated water W1 with high cleanliness can be stably supplied. [Explanation of symbols]

[0070] 1 Water treatment equipment 2 Supply Line 3. Tank 4. Pump 5. Ion Removal Method 6. First particle capture means 7. Particle counter (means for measuring particles) 8 Three-way valve (flow path switching means) 9 Processing flow path 10. Particulate removal channel 11 Second particle capture means (auxiliary particle capture means) 12 Confluence 13 Drainage channel W Water to be treated W1 Treated water

Claims

1. A water treatment device having a tank, a particulate capture means or an ion removal means, and a particulate measurement means, A flow path switching means is provided in front of the tank, the particle capture means or the ion removal section, The flow path switching means is capable of switching between a treatment flow path connected to the tank, the particulate capture means or the ion removal section, and a particulate removal flow path equipped with an auxiliary particulate capture means, and the particulate removal flow path merges with the treatment flow path downstream of the flow path switching means after passing through the auxiliary particulate capture means.

2. The water treatment device according to claim 1 , wherein the particulate measuring means is provided in front of the tank, the particulate capturing means, or the ion removing means.

3. The water treatment device according to claim 2 , wherein the flow path switching means is provided downstream of the particulate matter measuring means.

4. 4. The water treatment device according to claim 1, further comprising a control means for switching the flow path switching means between the treatment flow path and the particle removal flow path based on measurement information from the particle measurement means.

5. A water treatment method for treating water to be treated in a water treatment device having a tank, a particulate capturing means or an ion removing means, and a particle measuring means, comprising: A water treatment method in which, based on the measurement value by the particulate measuring means, the treated water is either supplied to a tank, a particulate capture means or an ion removal section, or the treated water passes through an auxiliary particulate capture means and then is supplied to a tank, an auxiliary particulate capture means or an ion removal section.

6. 6. The water treatment method according to claim 5, wherein the particulate measuring means is provided upstream of the tank, the particulate capturing means, or the ion removing means.

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