JPH0938671A - Water treatment and water treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment method capable of greatly enhancing the efficiency of use of ozone gas and also surely and inexpensively dissolving a desired concentration of ozone with a smaller capacity of centrifugal pump or smaller numbers of centrifugal pumps than heretofore, and attaining space saving. SOLUTION: In this water treatment method, a part of water to be treated is taken out from a main piping 19 in which the water to be treated flows, and is branched to a bypass piping 21, and ozone is dissolved into the water to be treated flowing in this bypass piping 21 by using the centrifugal pump 23, and then, the ozone water is joined with a main stream of the water to be treated flowing from the bypass piping 2 in the main piping 19.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water treatment method and a water treatment apparatus for efficiently dissolving ozone in water to be treated in order to treat impurities existing in the water to be treated.

[0002]

2. Description of the Related Art Ozone is used for water treatment such as sterilization of waterworks and wastewater treatment because it is excellent in oxidizing ability and sterilizing ability, and is also used for water treatment during ultrapure water production in the electronics industry. There is. In the former case, ozone is used for sterilizing treatment of microorganisms or for oxidizing and decomposing organic substances. Also, in the latter case, ozone is used for the same purpose as in the former case. As for ozone, it is general that ozone gas produced by an ozone generator is dissolved in water to be treated and reacted with impurities in the water to be treated. As a conventional method of dissolving ozone in the water to be treated, bubbling ozone gas generated in the ozone generator into the water to be treated from the diffuser pipe in the reaction tower containing the water to be treated to dissolve the ozone in the water to be treated. An aeration tank system and an ejector system in which a jet water flow of water to be treated is created by using an ejector, ozone gas is sucked by the jet water flow, and ozone gas is dissolved in the jet water flow are being studied.

On the other hand, for example, Japanese Patent Application Laid-Open No. 3-146123 (Japanese Patent Publication No. 4-74049) proposes an ozone water producing apparatus for efficiently dissolving ozone in water. This device is equipped with a vortex pump in the middle of water circulation,
High concentration ozone water is produced by introducing ozone into the suction side of the vortex pump and pressurizing and stirring the water mixed with the ozone gas by the impeller in the vortex pump.

[0004]

However, in the case of the former ozone dissolution method in the conventional water treatment method and water treatment apparatus, the ozone dissolution efficiency due to bubbling and the ejector is poor, and a large amount of ozone gas is scattered. There is a problem that the use efficiency of ozone is poor and the cost becomes high, and that a separate device for decomposing and processing the scattered ozone gas to render it harmless is required. Further, in the case of the latter dissolution method using a vortex pump, the former problem can be solved and the use efficiency of ozone gas can be increased, and a high concentration of ozone water can be obtained. When the volume of treated water increases, the size of the eddy current pump must be increased in order to secure that capacity, and multiple eddy current pumps must be used, which makes the cost of the eddy current pump much higher. In addition, there is a problem that the space dedicated to the vortex pump needs to be secured widely, which is against the trend of space saving.

The present invention has been made in order to solve the above problems, and it is possible to remarkably improve the use efficiency of ozone gas, and to reliably and reduce ozone of a desired concentration to a large flow rate of water to be treated. Can be dissolved at cost,
Moreover, it is an object of the present invention to provide a water treatment method and a water treatment apparatus that can achieve space saving.

[0006]

As a result of various studies on the method of efficiently dissolving ozone in the water to be treated in the water treatment step, the present inventors have found that even if the amount of treated water per unit time becomes large. , It was found that a water treatment method and a water treatment apparatus capable of dissolving ozone to a desired concentration can be obtained by using a vortex pump under specific conditions.

That is, in the water treatment method according to the first aspect of the present invention, a part of the main flow path through which the water to be treated flows is withdrawn and split into a branch flow channel, and the water to be treated flowing through the branch flow channel is treated. After the ozone is dissolved by using the vortex pump, the ozone-dissolved water to be treated is merged with the main stream of the water to be treated flowing from the branch channel to the main channel.

Further, in the water treatment apparatus according to the second aspect of the present invention, the main flow path through which the water to be treated flows and a part of the water to be treated flowing through the main flow channel are diverted and then the main stream of the water to be treated is main stream. And a vortex pump which is disposed in the branch channel and dissolves ozone into the water to be treated flowing in the branch channel.

Further, in the water treatment method according to the third aspect of the present invention, a part of the main flow path in which pure water produced by ion exchange and / or membrane treatment flows as the water to be treated is withdrawn to form a branch flow path. The ozone is dissolved in the water to be treated flowing through the branch channel by using a vortex pump, and then the ozone-dissolved water is joined with the main stream of the water to be treated flowing through the main channel from the branch channel. It is characterized by that.

The water treatment apparatus according to a fourth aspect of the present invention is a water treatment apparatus in which pure water produced by ion exchange and / or membrane treatment flows as water to be treated, and water to be treated flowing in the main passage. And a vortex pump which is disposed in the branch flow channel and dissolves ozone in the water to be treated flowing in the branch flow channel. It is characterized by that.

The water treatment method according to a fifth aspect of the present invention is a method for treating water from a main flow path in which waste water after washing objects to be washed such as semiconductor wafers, semiconductor devices, and other electronic parts flows as the water to be treated. After extracting a part of the water and branching it to the branch flow path, ozone is dissolved in the water to be processed flowing through the branch flow path by using a vortex pump, and then the ozone-dissolved water is discharged from the branch flow path to the main flow path. It is characterized in that it merges with the main stream of the water to be treated.

A water treatment apparatus according to a sixth aspect of the present invention is a main flow path, in which wastewater after washing objects to be washed such as semiconductor wafers, semiconductor devices, and other electronic parts flows as treated water. A branch flow path that divides a part of the water to be processed flowing through the main flow path and then joins with the main stream of the water to be processed, and the water to be processed that is disposed in the branch flow path and flows ozone through the branch flow path. And a vortex pump that dissolves in the water.

[0013]

According to the first and second aspects of the present invention, a portion of the water to be treated, which is commensurate with the water supply capacity of the vortex pump, is withdrawn from the main channel and is branched into the branch channel. After that, this swirl pump is used to dissolve ozone in the water to be treated that flows through the branch flow path to create high-concentration ozone-dissolved water (ozone water). By joining the main stream of the water to be treated, ozone having a desired concentration can be dissolved in the water to be treated.

According to the third and fourth aspects of the present invention, for example, in the case of producing ultrapure water, pure water produced by ion exchange and / or membrane treatment is treated water. After extracting a part of it from the main flow path that flows as a flow rate suitable for the water supply capacity of the vortex flow pump and dividing it into a branch flow path, ozone is dissolved in the water to be treated flowing through the branch flow path using this vortex flow pump. It is possible to dissolve ozone of a desired concentration into the water to be treated by making high-concentration ozone-dissolved water to be treated (ozone water) and joining this ozone water with the main stream of the water to be treated flowing from the branch channel to the main channel. it can.

According to the fifth and sixth aspects of the present invention, the drainage after cleaning the object to be cleaned such as the semiconductor wafer and the semiconductor device flows from the main flow path as the water to be treated. Part of the water is extracted at a flow rate that matches the water supply capacity of the vortex pump, and is branched into the branch flow path, and then ozone is dissolved in the water to be processed flowing through this branch flow path using a vortex flow pump to dissolve ozone at a high concentration. By making water (ozone water) and merging this ozone water with the main stream of the water to be treated which flows through the main channel from the branch channel, ozone of a desired concentration can be dissolved in the water to be treated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. In each figure, FIG. 1 is a flow chart showing an example of an ultrapure water production system to which an embodiment of the water treatment apparatus of the present invention is applied, and FIG. 2 is a primary pure water system of the ultrapure water production system shown in FIG. FIG. 3 is a flow chart showing the main part of FIG. 3 and FIG. 3 is a flow chart of the waste water recovery system of the ultrapure water production system shown in FIG.

As shown in FIG. 1, an ultrapure water production system to which the water treatment system of the present embodiment is applied includes a pretreatment system 1 for pretreating raw water such as industrial water, river water or groundwater as treated water. , A tank 2 for storing the treated water treated in the pretreatment system 1, a primary pure water system 3 for treating the water in the tank 2 to produce pure water, and a primary pure water system 3 surrounded by a dashed line And a secondary pure water system (subsystem) 4 for further purifying the pure water from 3 to produce ultrapure water. The ultrapure water produced by this ultrapure water production system is
A part of the ultrapure water supplied to the use points U for cleaning semiconductor wafers or semiconductor devices in the semiconductor manufacturing process and used as respective cleaning water and supplied to the use points U is constantly supplied to the tank 12 by the circulation pipe 50. It circulates. In recent years,
Since the drainage from the use point U is reused as much as possible due to the limitation of use of industrial water, the limitation of pumping of river water, and the ground water, the drainage from the use point U is used in the ultrapure water production system of this embodiment. Wastewater collection system 5 to collect
Is attached. In this waste water recovery system 5, 60 to 70% of waste water is recovered and used as raw water of ultrapure water.

Next, each of the above systems will be described in more detail. The pretreatment system 1 is usually equipped with a coagulation-sedimentation device, a filter, and the like, and these constituent devices are used to remove turbid components and organic colloid substances contained in the raw water. It is designed to reduce the load caused by pollutants in. The water treated by the pretreatment system 1 is temporarily stored in the tank 2. Further, the primary pure water system 3 has a configuration described later and is designed to remove ions, fine particles, microorganisms, organic substances and dissolved gas. Subsequent subsystem 4 further removes a small amount of ions in the treated water of primary pure water system 3 for polishing and also removes fine particles, organic matter, etc., in order to remove fine particles, organic substances, etc., by an ultraviolet oxidation device, a non-regenerative cartridge polisher, and an ultrafiltration. And the like (none of which are shown).

By the way, the primary pure water system 3 is used in the tank 2
A carbon filter (CF) 6 that removes organic substances and residual chlorine in the water to be treated supplied from the water, and cation exchange that removes cations such as sodium ions, calcium ions, and magnesium ions from the treated water flowing out of the carbon filter 6. Tower (CER) 7 and cation exchange tower 7
Decarbonation tower (D) 8 for degassing the dissolved carbon dioxide gas of the treated water flowing out of the water, and an anion exchange tower (AER) for removing anions such as sulfate ions and chlorine ions from the treated water flowing out of the decarbonation tower 8 9 and a tank 14 that stores water after these treatments.

Further, the primary pure water system 3 is an oxidizer (O ₃ -U) for ionizing a small amount of silica component remaining in the water to be treated or oxidizing an organic component by using ozone and ultraviolet rays.
V) 15 and a vacuum degassing tower (VD) 1 for degassing dissolved gas such as dissolved oxygen in the treated water flowing out of the oxidizer 15 in a vacuum.
6 and a mixed bed type ion exchange column (M) for further removing cations and anions from the treated water flowing out of the vacuum degassing column 16.
A BP) 17, a reverse osmosis device (RO) 18, and a tank 12 for storing the primary pure water after these treatments.
Each device constituting the ultrapure water production system is connected by a main pipe 19, and a water supply pump is arranged at a main part of the pipe.

Here, the oxidizer 15 which constitutes the main part of this embodiment will be described in detail. As shown in FIG. 2, the oxidizing device 15 is a device for ionizing, oxidizing, or decomposing silica, organic matter, and the like remaining in the water to be treated supplied from the tank 14 by dissolving ozone and irradiation of ultraviolet rays. A main pipe 19 as a passage, a water supply pump 20 for flowing water to be treated in the main pipe 19, and A on the downstream side of the water supply pump 20.
Detour as a branch flow path that branches at a point, part of the water to be treated flowing through the main pipe 19 is branched and diverted, and then merges with the main stream of the water to be treated in the main pipe 19 at the point B on the downstream side of the point A. The pipe 21 and the ozone gas generated in the ozone generator 22 which is disposed in the bypass pipe 21 are dissolved in the water to be treated flowing in the bypass pipe 21 and the water to be treated in which ozone is dissolved is transferred to point B of the main pipe 19. Swirl pump 23
And In this embodiment, the main pipe 19 shown in FIG.
The main stream of the water to be treated flows inside, and a part of the main stream, for example, 1/10 of the water to be treated is diverted in the bypass pipe 21, and the ozone gas is dissolved in the water to be treated by the vortex pump 23 to obtain a high concentration (for example, about 10 ppm). The ozone water of (1) is produced and the produced ozone water is caused to flow to the downstream side of the bypass pipe 21. Further, this ozone water merges with the main stream at point B on the downstream side of the vortex pump 23, and after the merge point, returns to the original flow rate and the ozone water has a concentration of 1/10, that is, a concentration of 1 ppm due to the treated water in the main stream. It is diluted so that, in other words, 1 ppm of ozone is added to the water to be treated and the ozone is allowed to flow to the next step.

The vortex pump 23 has a casing and an impeller rotatably supported in the casing, and a pressurizing passage is formed between the inner peripheral surface of the casing and the outer periphery of the impeller. . Then, when the ozone gas is sucked together with the water to be treated from the suction port (the side connected to the point A of the main pipe 19 in FIG. 2) of the swirl pump, the impeller is agitated while these both pass through the pressurizing passage. The action and the action of the pressurizing passage combine to form ozone water having a high concentration (for example, about 10 ppm) by dissolving ozone gas in the water to be treated and connecting the discharge port (point B of the main pipe 19 in FIG. 2). The ozone water is discharged from the side where

Further, the oxidizing device 15 is a gas-liquid separating device 24 for removing the residual gas in the water to be treated after the addition of ozone.
And a circulation type ultraviolet irradiation device 25 for irradiating the treated water containing ozone flowing out of the gas-liquid separation device 24 with ultraviolet rays, so that the mixed bed type ion exchange tower 17 in the subsequent step can be polished, that is, ultraviolet rays. By the action of ozone, the silica remaining in the water to be treated is ionized, and organic substances and the like are oxidized and decomposed. It should be noted that hydrogen peroxide is generated in the water to be treated due to the dissolution of ozone gas and the irradiation of ultraviolet rays, which may deteriorate the ion exchange resin and the like in the subsequent process. Therefore, the oxidation device 15 includes a carbon filter (CF) 26. Is provided, and hydrogen peroxide is decomposed and removed by the carbon filter 26.

The waste water recovery system 5 connected to the point of use U removes acids such as hydrofluoric acid and sulfuric acid contained in the cleaning waste water mainly discharged from the point of use U by ion exchange and silica, A system that ionizes or oxidizes and decomposes organic matter and the like by irradiating dissolved ozone and ultraviolet rays, and removes the treated water purified here as raw water of ultrapure water, as shown in FIG. It is adapted to be returned to the tank 14 via a pipe 51. As shown in FIG. 3, the wastewater recovery system 5 includes a main pipe 19 as a main flow path through which wastewater flows as treated water, and a water feed pump 2 for sending the treated water in the main pipe 19.
7 and a point C on the downstream side of the water supply pump 27, a part of the water to be treated flowing through the main pipe 19 is branched off, and then the main stream of the water to be treated and the upstream side from the point C and above A return pipe 28 serving as a branch flow passage that joins in the main pipe 19 on the downstream side of the water supply pump 27, and ozone gas generated in the ozone generator 22 which is arranged in the return pipe 28 is introduced into the water to be treated flowing in the return pipe 28. The ozone water produced is dissolved and the produced ozone water is returned through the return pipe 28 to C
And a vortex pump 29 that moves the point up to the point D. Therefore, in the vortex pump 29 in FIG. 3, the directions of the suction port and the discharge port are opposite to those in the case of FIG.

Further, this waste water recovery system 5 is disposed upstream of the ozone addition position (point D) and is a weakly basic anion exchange tower (for removing anions such as fluorine ions contained in the waste water ( WAER) 30 and also
Oxidizing organic matter, which is disposed downstream of point D and cannot be removed by the weakly basic anion exchange column 30, in cooperation with ozone,
An ultraviolet irradiation device 31 for decomposing, a carbon filter (CF) 32 for removing a minute amount of hydrogen peroxide generated in the ultraviolet irradiation device 31, and a mixed bed type ion exchange tower (MBP) 33 for removing residual impurity ions are provided. ing. The weakly basic anion exchange tower 30 is an ultraviolet irradiation device 31.
It is installed mainly for removing the hydrofluoric acid that corrodes the quartz glass tube of the ultraviolet irradiation lamp 35 inside. The ultraviolet irradiation device 31 shown in FIG. 3 is an immersion type in which the ultraviolet irradiation lamp 35 is immersed in the water to be treated in the closed reaction tank 36, and the top of the reaction tank 36 is degassed. A pipe 37 is attached.

Next, the operation will be described. When raw water such as industrial water is taken to produce ultrapure water and sent to the pretreatment system 1, the pretreatment system 1 removes turbid components and organic colloid substances contained in the raw water. The treated water is temporarily stored in the tank 2 as treated water in the next step. When the water to be treated in the tank 2 is sent to the primary pure water system 3, the primary pure water system 3 uses a two-bed, three-column type ion exchange device (reference numeral 7 in FIG. 1).
~ 9), vacuum degassing tower 16, mixed bed type ion exchange tower 17, reverse osmosis device 18, etc. are used to remove ions, fine particles, microorganisms, organic substances, dissolved oxygen, etc. from the water to be treated to make pure water. Water is temporarily stored in the tank 12. Next, in the subsystem 4, the pure water from the primary pure water system 3 is finally polished as the water to be treated to remove a minute amount of ions, fine particles, viable bacteria and the like contained in the pure water to obtain ultrapure water. The ultrapure water is supplied to the use point U and used as cleaning water for semiconductor wafers, semiconductor devices and the like.

By the way, in the oxidizing device 15 of the primary pure water system 3, the following water treatment is performed. That is, while the water to be treated in the tank 14 is sent to the downstream side by the water pump 20 through the main pipe 19 at a flow rate of, for example, 10 m ³ / h,
A part of the water to be treated is extracted from the point A of the main pipe 19 by the vortex pump 23, and is branched into the bypass pipe 21 at a flow rate of 1 m ³ / h and branched. The swirl pump 23 pressurizes and agitates the extracted water to be treated and the ozone gas supplied from the ozone generator 22 to produce high-concentration (for example, about 10 ppm) ozone water, and the ozone water is supplied from the bypass pipe 21 to the main pipe. 19
1p of ozone water by merging with the main stream of the water to be treated inside at point B
After being diluted to pm, it is allowed to flow into the gas-liquid separation device 24 from the confluence point through the main pipe 19 together with the action of the water pump 20.

The gas-liquid separator 24 removes the residual gas in the ozone water. When the ozone water after gas-liquid separation is made to flow into the ultraviolet irradiation device 25, the silica remaining in the ozone water is ionized or the organic matter is oxidized and decomposed by the action of ozone and ultraviolet rays, and then the carbon filter 26 is used.
Flow into. The carbon filter 26 decomposes and removes hydrogen peroxide remaining in the treated water, and prevents damage to the ion exchange resin and the like filled in the mixed bed type ion exchange tower in the subsequent step.

In addition, metal ions generated by cleaning semiconductor wafers and semiconductor devices, acids such as hydrofluoric acid and sulfuric acid used for cleaning, or organic substances such as low molecular weight alcohol are mixed in the wastewater from the use point U. are doing. Therefore, the wastewater recovery system 5 is used to purify the wastewater. In this waste water recovery system 5, the waste water is first passed through the weakly basic anion exchange column 30 by the water pump 27 to remove hydrofluoric acid, sulfuric acid and other acids in the waste water. Then, the treated water is passed through the main pipe 19 and the ultraviolet irradiation device 31 on the further downstream side.
To the return pipe 28A at the point D on the way.
High concentration (eg 10pp
(about m) of ozone water is injected and diluted in the main pipe 19 to, for example, about 1 ppm (however, the flow rate of the high-concentration ozone water injected from the return pipe 28A is equal to that of the water to be treated flowing through the main pipe 19). 1/10).

At the point D, the water to be treated added with ozone is sent further downstream, but at a point C on the way, a part of this water to be treated is extracted by the action of the vortex pump 29 and branched to the return pipe 28A. In the vortex pump 29, as described above, ozone gas from the ozone generator 22 is dissolved in the waste water to produce ozone water, and this ozone water is supplied from the return pipe 28A to the main flow of the waste water in the main pipe 19 and the point D as described above. At the same time, they are combined to dilute ozone water to a concentration of about 1/10.

After that, the water to be treated in which ozone water is dissolved by about 1 ppm is sent to the ultraviolet irradiation device 31, and the ultraviolet irradiation device 31 irradiates the water to be treated with ultraviolet rays in the reaction tank 36 to mix it into the water to be treated. After oxidizing, decomposing or sterilizing the organic substances and bacteria etc. that have been made by the action of ozone and ultraviolet rays,
It flows into the carbon filter 32. In the reaction tank 36, the residual gas in the water to be treated is discharged from the gas vent pipe 37, so that the gas-liquid separation device shown in FIG. 2 is unnecessary. After decomposing and removing the hydrogen peroxide remaining in the wastewater after the oxidation and decomposition treatment in the carbon filter 32, the treated water is passed through the mixed bed type ion exchange tower 33 and the ions generated during the oxidative decomposition treatment and originally Impurity ions such as metal ions contained therein are removed to obtain pure water, and the pure water thus obtained is returned to the tank 14 of the primary treatment system. In the oxidation device shown in FIG. 3, the immersion type ultraviolet irradiation device 3 is used.
It is also possible to use a circulation type ultraviolet irradiation device similar to that shown in FIG. 2 in place of 1. In that case, the gas-liquid separation device is arranged between points D and C in FIG. May be.

As described above, according to the present embodiment, for example, as a method of dissolving ozone gas in water to be treated in the process of producing primary pure water of ultrapure water, the water to be treated after ions are removed flows. One-tenth of the main pipe 19 was extracted and branched to the bypass pipe 21, and ozone gas was dissolved in the water to be treated flowing through the bypass pipe 21 by using the vortex pump 23 to produce high-concentration (10 ppm) ozone water. After that, this ozone water is combined with the main stream of the water to be treated flowing from the bypass pipe 21 through the main pipe 19 to dilute the high-concentration ozone water to obtain a desired ozone concentration (1 ppm). Therefore, even if the water to be treated has a large flow rate, it is possible to surely dissolve the ozone of a desired concentration at a low cost by using a small number or a small number of swirl pumps 23.

Although the water treatment method and apparatus for producing ultrapure water have been described in the above embodiments, the water treatment method and apparatus of the present invention are not limited to the above embodiments, and ozone gas is not limited thereto. The present invention can be applied to all of the water treatments (for example, deodorization and sterilization of water supply, COD removal treatment of sewage, etc.).

[0034]

According to the invention described in claims 1 to 6 of the present invention, the use efficiency of ozone gas can be remarkably increased, and the conventional method can be used even when a large amount of water to be treated is treated. (EN) Provided are a water treatment method and a water treatment apparatus which can surely dissolve ozone of a desired concentration at a low cost with a smaller capacity or a smaller number of swirl pumps and can achieve space saving. be able to.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of an ultrapure water production system to which an embodiment of the water treatment system of the present invention is applied.

FIG. 2 is a flow chart showing an essential part of a primary pure water system of the ultrapure water production system shown in FIG.

FIG. 3 is a flow chart of a wastewater recovery system of the ultrapure water production system shown in FIG.

[Explanation of symbols]

 7 Cation Exchange Tower 8 Decarbonation Tower 9 Anion Exchange Tower 18 Reverse Osmosis Device (Membrane Treatment) 19 Main Pipe (Main Flow Path) 21 Detour Pipe (Branch Flow Path) 23 Vortex Pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01L 21/304 341 H01L 21/304 341L

Claims (6)

[Claims] 1. A part of the main flow path through which the water to be treated flows is extracted and split into a branch flow channel, and ozone is dissolved in the water to be treated flowing through the branch flow channel by using a vortex pump, and then this ozone is discharged. A water treatment method, characterized in that the dissolved water to be treated is merged with the main stream of the water to be treated flowing from the branch channel to the main channel. 2. A main flow passage through which the water to be treated flows, a branch flow passage for dividing a part of the water to be treated flowing through the main flow passage and then joining the main flow of the water to be treated, and a branch flow passage arranged in the branch flow passage. And a swirl pump that dissolves ozone in the water to be treated flowing through the branch flow path. 3. Pure water produced by ion exchange and / or membrane treatment is withdrawn from a main flow path that flows as water to be treated, and a part of the water is branched off into a branch flow path. A method for treating water, characterized in that ozone is dissolved by using a vortex pump, and then this ozone-dissolved water to be treated is merged with the main stream of the water to be treated flowing from the branch channel to the main channel. 4. A main flow path in which pure water produced by ion exchange and / or membrane treatment flows as water to be treated, and a part of the water to be treated flowing in the main flow channel is diverted, and then the main stream of the water to be treated is divided. And a vortex pump disposed in the branch channel and dissolving ozone in the water to be treated flowing in the branch channel. 5. A part of a main flow path, from which waste water after cleaning an object to be cleaned such as a semiconductor wafer, a semiconductor device, and other electronic parts flows as water to be treated, is branched off into a branch flow path, and this branch is performed. The method is characterized in that after ozone is dissolved in the water to be treated flowing through the flow path using a vortex pump, the ozone-dissolved water to be treated is merged with the main stream of the water to be treated flowing through the main channel from the branch channel. Water treatment method. 6. A main flow path through which wastewater after cleaning an object to be cleaned such as a semiconductor wafer, a semiconductor device, and other electronic components flows as water to be treated, and a part of the water to be treated flowing through this main channel is divided. And a vortex pump disposed in the branch flow path and dissolving ozone in the water to be processed flowing in the branch flow path. Water treatment equipment.