KR20070057671A - Method and apparatus for treating water containing surfactant - Google Patents

Abstract

A method and an apparatus for treating water containing the surfactant are provided to stably treat the water containing surfactant by suppressing foaming of the water containing the surfactant due to injection of ozone-containing gas when treating water containing a surfactant having a high foamability with ozone. An apparatus(1) for treating water containing a surfactant comprises: a flow path(5) through which surfactant-containing water as a liquid to be treated flows; and a front side ozone reaction equipment(10) and an end side ozone reaction equipment(20). The flow path has an entrance(51) and an exit(52). The apparatus further comprises: a first hydrogen peroxide injection pipe(31) and a second hydrogen peroxide injection pipe(32) of which one ends are connected to a hydrogen peroxide storage tank(30), and of which the other ends are connected to the flow path; and a first alkali injection pipe(41) and a second alkali injection pipe(42) of which one ends are connected to an alkali storage tank(40), and of which the other ends are connected to the flow path. The front side ozone reaction equipment comprises a vortex flow pump(11) and an ozone injection pipe(12) of which one end is connected to the flow path. The end side ozone reaction equipment comprises a gas-liquid contact type reactor(22) having a water spraying pipe(23) and an air diffuser(21).

Description

Method and apparatus for treating water containing surfactant

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the processing apparatus of surfactant containing water which concerns on one Embodiment of this invention.

<Description of main parts of drawing>

1: processing unit

5: euro

10: front side ozone reaction equipment

11: vortex pump

12: ozone injection tube

20: final stage ozone reaction equipment

21: diffuser

22: reactor

23: water pipe

25: ozone generator

25A: with ozone

31: first hydrogen peroxide injection tube

32: second hydrogen peroxide injection tube

41: first alkali injection tube

42: second alkali injection tube

51: entrance

52: exit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment method and treatment apparatus for surfactant-containing water such as electronic component cleaning wastewater, and more particularly, to a treatment method and treatment apparatus for surfactant-containing water by ozone gas.

BACKGROUND ART Conventionally, ultrapure water having extremely low impurity concentrations is used as cleaning water for cleaning wafers and the like in a semiconductor manufacturing plant and a display device manufacturing plant such as a liquid crystal. However, cleaning with only ultrapure water may make it difficult to clean minute parts such as wafers due to surface tension. Therefore, recently, a method of cleaning a wafer or the like by adding organic substances such as surfactant or alcohol to ultrapure water to lower the surface tension is used.

For this reason, the wastewater discharged from a semiconductor manufacturing process etc. may contain surfactant added to ultrapure water. As a method for treating surfactant-containing water such as electronic component cleaning wastewater, activated carbon adsorption, foam separation, chemical decomposition, and biological treatment are known. Examples of the chemical decomposition method include an ultraviolet irradiation method for irradiating ultraviolet rays to water containing surfactant, an oxidizer addition method for adding an oxidizing agent such as ozone, and the like.

For example, Patent Document 1 discloses a method for treating surfactant-containing water in which hydrogen is added after ozone is added to the surfactant-containing water. In the method disclosed in Patent Document 1, ozone is added to the surfactant-containing water to oxidatively decompose the surfactant. Next, oxidizing agents such as ozone remaining in the treated water are reduced by adding hydrogen.

<Patent Document 1> Publication No. 2000-271577

As ozone generation methods, there are a discharge method for generating ozone by discharging air or oxygen as a raw material and an electrolysis method for generating ozone by electrolysis of pure water. In the electrolytic method, it is preferable to use ozone generated by the electrolytic method in Patent Literature 1, for example, in order to obtain an ozone aqueous solution having an ozone concentration of about 20% by mass. However, since ozone that can be generated by the electrolytic method is less than about 1 g / h, the electrolytic method cannot generate a large amount of ozone.

On the other hand, according to the discharge system, ozone of about 300 kg / h can be generated. For this reason, when ozone is processed with a large amount of surfactant containing water conventionally, the ozone containing gas produced | generated by the discharge system is used. However, the ozone concentration of ozone-containing gas containing ozone generated by the discharge system is low. For example, the ozone concentration of an ozone-containing gas generated by using air as a raw material is about 40 g / Nm ³ (2.7 mass%), and the ozone-containing gas generated by using oxygen as a raw material has an ozone concentration of 150 to 200 g /. It stays at about Nm ³ (10 ~ 13 mass%).

Therefore, in order to oxidatively decompose organic substances, such as surfactant contained in surfactant containing water, it is necessary to inject a large amount of ozone containing gas into surfactant containing water. For example, if the amount of ozone required to decompose total organic carbon (TOC) contained in surfactant-containing water is 8 times the mass ratio (TOC) of TOC, the amount of ozone required for wastewater treatment with a TOC concentration of 20 mg / L is 160 mg. / L In this case, even if an ozone-containing gas having a concentration of 150 mg / L is used, the gas-liquid ratio of the reaction tank that oxidizes and decomposes by ozone exceeds 1.0. Viii) occurs.

In particular, intense foaming occurs when a surfactant-containing water containing a nonionic surfactant as a TOC component is introduced into a reaction tank and an ozone-containing gas is injected from an acid pipe provided in the lower part of the reaction tank. As a result, trouble arises that bubbles cannot flow out of the waste ozone tube which cannot stabilize the gas-liquid interface of the reaction tank and discharge the waste ozone-containing gas.

The present invention provides a treatment method and a treatment apparatus for a surfactant-containing water capable of suppressing foaming caused by the injection of an ozone-containing gas during ozone treatment of surfactant-containing water having high foamability and performing stable treatment. For the purpose of

Specifically, the present invention provides the following.

(1) A method for treating surfactant-containing water in which ozone is added to surfactant-containing water, wherein the surfactant-containing water flows in a flow path having an inlet and an outlet, and the ozone is introduced at a plurality of positions along the flow path. A method for treating surfactant-containing water, which is added to the surfactant-containing water and adds the most ozone at the position closest to the outlet.

(2) The method for treating surfactant-containing water according to (1), wherein an alkali is added to the surfactant-containing water before the ozone is added.

(3) The method for treating surfactant-containing water according to (1), wherein an alkali and hydrogen peroxide are added to the surfactant-containing water before adding the ozone.

(4) An apparatus for treating surfactant-containing water, comprising a flow passage through which the surfactant-containing water flows from the inlet to the outlet, wherein the ozone is added to the surfactant-containing water flowing along the flow passage and adding a surfactant. And a plurality of ozone reaction facilities for oxidatively decomposing the same, wherein the final stage ozone reaction facility provided at a position closest to the outlet among the plurality of ozone reaction facilities contains more ozone than other ozone reaction facilities. Treatment apparatus of surfactant containing water added to containing water.

(5) The final stage ozone reaction facility is a gas-liquid contact type reaction tank having an ozone supply means, and the ozone supply means in the flow path for supplying the ozone to the flow path as the other ozone reaction facility and the surface-active water in the flow path. The treatment apparatus of surfactant containing water as described in (4) containing the stirring reaction installation which has a stirring means for stirring.

(6) The interface according to (4) or (5), which is provided at a position close to the inlet from at least one of the plurality of ozone reaction facilities and further includes alkali addition means for adding alkali to the surfactant-containing water. Treatment apparatus for active agent-containing water.

(7) an alkali addition means for adding alkali to the surfactant-containing water and a hydrogen peroxide addition means for adding hydrogen peroxide, provided at a position close to the inlet from at least one of the plurality of ozone reaction facilities (4) Or the apparatus for treating surfactant-containing water according to (5).

The liquid to be treated according to the present invention contains at least a surfactant. The concentration of the surfactant is not particularly limited, and, for example, the concentration of the surfactant is 3 to 30 mg / L, and the TOC concentration of the surfactant-containing water having an organic matter other than the surfactant is about 5 to 50 mg / L. It can be used for processing. In particular, the present invention can be used in low-TOC concentration wastewater, such as wastewater from an electronic component manufacturing plant, specifically, a surfactant having a concentration of 1 to 5 mg / L and a TOC concentration of 2 to 10 mg / L. It can also be applied to water containing.

In particular, the present invention can be suitably used for the treatment of surfactant-containing water containing a highly foamable nonionic surfactant. Suitable. However, the kind of surfactant is not specifically limited, Use of this invention for the treatment of surfactant containing water containing an ionic surfactant containing anionic surfactant and cationic surfactant is not excluded. Examples of nonionic surfactants include polyoxyethylene alkyl ethers (AE), polyoxyethylene alkyl phenyl ethers (APE), fatty acid alkanolamides, and polyoxyethylene sorbitan fatty acid esters.

Ozone can be added to surfactant-containing water as an ozone-containing gas produced by using air or oxygen as a raw material, and it is not excluded to use ozone produced by an electrolytic method. The amount of ozone added is preferably an amount necessary for completely decomposing the surfactant to the carbon dioxide gas (hereinafter referred to as 'complete decomposition' amount). However, depending on the reaction efficiency, ozone exceeding the required amount of complete decomposition may be added, and in the case of performing biological treatment, adsorption treatment, or deionization after the treatment according to the present invention, the addition amount below the required amount of complete decomposition You may make it.

Specifically, when the surfactant is completely decomposed to carbon dioxide gas, the amount of ozone added is preferably 20 to 50 times (mass ratio) relative to the surfactant. In the case of biological treatment after the treatment according to the present invention, it is preferable that the amount of ozone is 2 to 10 times (mass ratio) relative to the surfactant to decompose the surfactant into a biodegradable form, that is, an organic acid or glycols. .

In the present invention, the ozone required to decompose the surfactant is added in a plurality of positions in a plurality of positions according to the flow direction of the surfactant-containing water flowing in a certain direction, and in particular, the most ozone is added at the final stage, i. . The amount of ozone added in the final stage is preferably 60 to 95% of the total amount added. In the present invention, by dividing the addition position of ozone into a plurality, depending on the reaction efficiency, the amount of ozone added at the final stage may be more than the preset addition amount, or vice versa.

The addition position of ozone should just be 2 or more places, and when the ozone addition position is made into 2 places, 5-40% of the total amount of ozone is added before a final stage and eventually the first ozone addition position. In addition, when making three or more places of ozone addition, the amount of ozone addition in several ozone addition positions other than a final stage may be mutually the same, and may differ. When there are many ozone addition sites, the decomposition rate of surfactant can be improved, and since there are many instruments required for ozone addition, it is preferable to set it as 2-3 places.

According to the present invention, when the ozone addition position necessary for the decomposition of the surfactant is divided into a plurality of places along the flow of the surfactant-containing water, the amount of ozone added per place is reduced as compared to the case where ozone is added at one place, thereby suppressing foaming. can do. In particular, in the present invention, high ozone decomposition efficiency can be obtained while suppressing foaming by adding most of the total amount at the final stage closest to the outlet of the surfactant-containing water flow path and reducing the amount of ozone added at the inlet side and the front end side than the final stage. Can be.

This is presumably because the surfactant is denatured by a small amount of ozone added at the inlet side reacting easily and quickly with a portion (the interface between the hydrophobic portion and the hydrophilic portion) showing the surfactant activity. That is, it is considered that foaming can be reduced by first modifying the surfactant by a small amount of ozone added at the inlet side, so that foaming can be suppressed even if a large amount of ozone is added at the final stage.

At the ozone addition position, an ozone reaction facility is installed in which ozone is reacted with the surfactant by adding ozone to the surfactant-containing water. The ozone reaction facility may be provided with an ozone supply means for adding ozone to the surfactant-containing water. However, in order to sufficiently react the ozone and the surfactant, it is preferable to further include a reaction tank in which the surfactant-containing water can remain for a predetermined time. Do. In particular, the ozone reaction facility (final-end ozone reaction facility) installed at the position closest to the outlet of the flow path containing the surfactant-containing water has a gas-liquid contact having an ozone supply means such as an acid engine to secure a reaction time between the surfactant and ozone. It is preferable to have a reactor of the type.

On the other hand, since the portion showing the surfactant activity of the surfactant has a high reaction rate with ozone, the ozone reaction facility (hereinafter, referred to as the shear shear ozone reaction facility) installed at the inlet side of the final stage ozone reaction facility is called the inside of the flow path. What is necessary is just to provide at least the ozone supply means in the flow path which adds ozone to a flowing surfactant. Examples of the ozone supply means in the flow passage include an ozone injection pipe, an ejector, a porous pipe, and a vortex pump with an air supply port. In particular, the front-side ozone reaction facility preferably includes stirring means having an action of stirring the surfactant-containing water in the flow path in addition to the ozone supply means in the flow path in order to increase the contact efficiency between ozone and the surfactant-containing water. As a stirring means, a vortex pump and a line mixer which can be operated with air are mentioned. In this way, the apparatus can be simplified by omitting the reaction tank in the front-side ozone reaction facility.

In the present invention, in order to promote the oxidation reaction by ozone, alkali may be added before adding ozone to the surfactant-containing water, and ozone may be added to the surfactant-containing water in the presence of alkali. It is preferable to make the addition amount of alkali into the quantity required in order to make pH of surfactant containing water into 9-11. The kind of alkali to add is not specifically limited, Sodium hydroxide, potassium hydroxide, etc. can be used.

In addition to the alkali, hydrogen peroxide may also be added to the surfactant-containing water. When alkali and hydrogen peroxide are added to surfactant containing water before ozone addition, the order of addition of alkali and hydrogen peroxide is not specifically limited. The amount of alkali added may be the same as in the case of not adding hydrogen peroxide, and the amount of hydrogen peroxide added is preferably about 0.1 to 1 in mass ratio relative to the amount of ozone added.

As described above, by adding alkali alone or with hydrogen peroxide to the surfactant-containing water and then adding ozone, hydroxyl radicals can be generated to promote the oxidation reaction. Alkali (and hydrogen peroxide) may be added prior to the addition of ozone at at least one of the divided ozone addition positions, but may be added before each ozone addition position. In particular, in order to improve the hydroxyl radical generation efficiency, it is preferable to add alkali (and hydrogen peroxide) in front of the ozone addition position closest to the outlet.

The shape of the reaction vessel is not limited, and it is preferable to have a configuration in which ozone-containing gas is supplied to the surfactant-containing water from the lower portion of the reaction vessel and the waste ozone-containing gas is discharged from the upper portion of the reaction vessel. Further, the water to be treated may be supplied from the lower part of the reaction tank, or an arithmetic means may be provided in the upper part of the reaction tank, and the treated water may be supplied from the arithmetic means. In this way, when water is splashed on the liquid surface, it is easier to suppress foaming.

According to the present invention, it is possible to add an amount of ozone necessary to suppress the foaming of the surfactant-containing water and to oxidatively decompose the surfactant. Therefore, according to the present invention, it is possible to treat the surfactant-containing water by decomposing the surfactant with high decomposition efficiency and at the same time preventing trouble caused by foaming.

To practice the invention  Best form for

Hereinafter, the present invention will be described in detail with reference to the drawings. The same reference numerals will be given to the same members, and descriptions thereof will be omitted or simplified. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the processing apparatus (henceforth simply a "processing apparatus") 1 of surfactant containing water which concerns on one Embodiment of this invention. The treatment apparatus 1 includes a flow passage 5 through which a surfactant-containing water containing a surfactant as a liquid to be treated flows, and a front-side ozone reaction facility 10 and a final stage ozone reaction facility 20 installed in the middle of the flow path 5. Include. The flow path 5 has an inlet 51 and an outlet 52, and the surfactant-containing water is introduced into the processing apparatus 1 into the inlet 51 so as to flow from the inlet 51 toward the outlet 52 and the outlet ( 52).

In this embodiment, the first hydrogen peroxide addition means and the first alkali addition means are provided on the inlet 51 side from the front-side ozone reaction facility 10. In addition, a second hydrogen peroxide addition means and a second alkali addition means are provided on the inlet 51 side from the final stage ozone reaction facility 20. As described above, these hydrogen peroxide addition means and alkali addition means may be omitted.

The hydrogen peroxide addition means may be constituted by a member capable of adding hydrogen peroxide to the surfactant-containing water flowing in the flow path 5, for example, connected to a reservoir where one end stores hydrogen peroxide. It is possible to make the piping. In the present embodiment, the first hydrogen peroxide addition means is constituted by the first hydrogen peroxide injection tube 31, and the second hydrogen peroxide addition means is constituted by the second hydrogen peroxide injection tube 32. Both ends of the first hydrogen peroxide injection tube 31 and the second hydrogen peroxide injection tube 32 are connected to the hydrogen peroxide reservoir 30, and the other end thereof is connected to a pipe forming the flow path 5. have.

The alkali addition means may be constituted by a member capable of adding alkali to the surfactant-containing water flowing in the flow passage 5, for example, connected to a reservoir where one end stores alkali. It is possible to make the piping. In this embodiment, the 1st alkali addition means is comprised by the 1st alkali injection tube 41, and the 2nd alkali addition means is comprised by the 2nd alkali injection tube 42. As shown in FIG. Both of the first alkali injection pipe 41 and the second alkali injection pipe 42 are connected to the alkali reservoir 40 at one end, and the other end is connected to the pipe forming the flow path 5. Connected.

The front-side ozone reaction facility 10 uses the vortex pump 11 as the stirring means provided in the middle of the flow path 5 and the ozone supply means in the flow path connected to the flow path 5 on the inlet 51 side from the vortex pump 11. It is configured to include. In the present embodiment, the ozone supply means in the flow passage may be constituted by a member for injecting the ozone-containing gas into the flow passage 5. For example, in this embodiment, an ozone injection pipe having one end connected to the flow passage 5. It consists of 12. The other end of the ozone injection tube 12 is connected to the ozone generator 25.

The final stage ozone reaction facility 20 has an arithmetic pipe 23 as a supply means to be treated water (treated water from the shear side ozone reaction facility 10) and an acid pipe 21 as an ozone supply means. It consists of the reaction tank 22 of a gas-liquid contact type. One end of the diffuser tube 21 is connected to the ozone generator 25, and the ozone-containing gas generated by the ozone generator 25 passes through the diffuser tube 21. 22) It is added to the surfactant containing water from the bottom. The size of the reaction tank 22 is not particularly limited, but it is preferable that the residence time of the surfactant-containing water is such that the time required for the surfactant to be oxidatively decomposed by ozone, for example, the residence time of the surfactant-containing water is 5 This should be ~ 10 minutes.

In the present embodiment, the ozone-containing gas generated in the ozone generator 25 is supplied to the ozone injection pipe 12 and the acid pipe 21 through the ozone furnace 25A. In the present invention, most of the ozone-containing gas (about 60 to 95%) added to the surfactant-containing water, in particular, is added to the surfactant-containing water from the final stage ozone reaction facility 20. For this reason, most of the ozone-containing gas generated in the ozone generator 25 is supplied to the diffuser 21, and about 5 to 40% of the generated ozone-containing gas is supplied to the ozone injection pipe 12. It is.

Next, the method of processing surfactant containing water using the said processing apparatus 1 is demonstrated. First, surfactant-containing water, such as semiconductor manufacturing wastewater, is introduced into the flow passage 5 from the inlet 51 as a liquid to be treated. If a pump or the like is installed in the middle of the flow path 5 and the surfactant-containing water flows from the inlet 51 side to the outlet 52 side so as to flow inside the flow path 5 at a speed of about 0.5 to 2 m / sec. good.

In the processing apparatus 1 according to the present embodiment, the first hydrogen peroxide injection tube 31, the first alkali injection tube 41, and the ozone injection tube are directed from the inlet 51 side to the outlet 52 side along the flow path 5. 12, the vortex pump 11, the 2nd hydrogen peroxide injection pipe 32, the 2nd alkali injection pipe 42, and the reaction tank 22 are provided in this order. The surfactant-containing water flowing in the direction from the inlet 51 side to the outlet 52 side is first flowed from the first hydrogen peroxide injection tube 31 from the first hydrogen peroxide injection tube 31 and the sodium hydroxide from the first alkali injection tube 41. Alkali, such as these, is added to adjust the pH to about 9-11.

Next, a small amount of ozone-containing gas is added from the ozone injection tube 12 to the surfactant having a raised pH. Immediately after the ozone injection pipe 12, a vortex pump 11 is provided, and the surfactant-containing water to which a small amount of ozone is added is stirred by the vortex pump 11. Since a small amount of ozone can be added to the front-side ozone reaction facility 10, the vortex pump 11 may be omitted. In addition, instead of providing the ozone injection pipe 12 and the vortex pump 11, an ejector and a line mixer may be provided in the middle of the flow path 5. As described above, the surfactant-containing water to which a small amount of ozone is added in the shear-side ozone reaction facility 10 is stirred with a vortex pump 11 or the like to impart a large shear force, so that a small amount of ozone can be efficiently reacted with the surfactant. .

In the front-side ozone reaction facility 10, the surfactant is modified by the addition of a small amount of ozone, thereby reducing the foamability. This is presumed to be due to the modification of the portion showing the surfactant activity of the surfactant by reacting mainly with the boundary portion between the hydrophobic portion and the hydrophilic portion of the surfactant. For this reason, even if a large amount of ozone is added in the final stage ozone reaction facility 20, foaming of a to-be-processed liquid can be suppressed. Therefore, in the present invention, about 5 to 40% of the total amount of ozone added to the surfactant-containing water in the treatment apparatus 1 in the front-side ozone reaction facility 10 is added, and the remaining stage ozone reaction facility 20 is added. Add positive ozone.

In addition, since the surfactant is denatured by the reaction of ozone with the surfactant to generate organic acid, the treatment apparatus 1 includes the second hydrogen peroxide injection tube 32 and the second alkali injection tube before the final stage ozone reaction facility 20. Install (42). As a result, hydrogen peroxide and alkali are added to the surfactant-containing water that has passed through the front-side ozone reaction facility 20, and the treatment in the final stage ozone reaction facility 20 is performed in a state where the oxidation reaction by ozone is promoted.

In the final stage ozone reaction facility 20, a treatment liquid (surfactant-containing water) is introduced into the reaction tank 22, and ozone-containing gas is injected from an acid pipe 21 connected to the lower portion of the reaction tank 22. The liquid to be processed is held in the reaction tank 22 for a predetermined time. In the final stage ozone reaction facility 20, most of the total amount of ozone (about 60 to 95%) added to the surfactant-containing water in the treatment apparatus 1 is added to the processing liquid to decompose the surfactant. The treated water in which the surfactant is decomposed after the treatment in the final stage ozone reaction facility 20 is discharged from the outlet 52, and, if necessary, subjected to post-treatment such as biotreatment to produce raw water for ultrapure water production. ) And the like.

<Example>

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on an Example. As an example, the treatment apparatus 1 shown in FIG. 1 was used, and surfactant containing water containing APE as surfactant was used as the to-be-processed liquid. Surfactant-containing water is synthetic wastewater prepared by dissolving APE in pure water to have a TOC concentration of 21 mg / L.

As the vortex pump 11, a vortex pump (manufactured by Nikuni Co., Ltd.) having an outlet pressure of 0.3 Mpa was used, and the surfactant-containing water flows inside the flow passage 5 from the inlet 51 toward the outlet 52 at a flow rate of 350 L / h. It was introduced into the processing apparatus 1 so that.

In this embodiment, hydrogen peroxide and alkali were added prior to the addition of ozone in each ozone reaction facility. As the hydrogen peroxide, one having a concentration of 35% by mass was used, and as the alkali, 4% by mass of sodium hydroxide was used. The amount of hydrogen peroxide added was 15 mg / L from the first hydrogen peroxide injection tube 31, and the amount of addition from the second hydrogen peroxide injection tube 32 was 250 mg / L. In addition, the second hydrogen peroxide injection pipe 32 was configured to be different from the processing apparatus 1 in FIG. 1 in that it was connected to the lower portion of the reaction tank 22 without being connected to the flow path 5.

On the other hand, sodium hydroxide was injected into the flow path 5 from each of the 1st alkali injection tube 41 and the 2nd alkali injection tube 42. As shown in FIG. The addition amount of sodium hydroxide was taken as the quantity which makes pH of surfactant containing water 10.

As the ozone generator 25, an apparatus for generating an ozone-containing gas having an ozone concentration of 150 g / Nm 3 using an oxygen as a raw material by a discharge method was used. The ozone-containing gas generated in the ozone generator 25 is injected into the flow path 5 from the ozone injection tube 12 at a feed rate of 20 L / h, and the diffuser tube 21 attached to the reaction tank 22 is provided. ), The feed rate was 350 L / h.

As the reaction tank 22, a cylindrical gas-liquid contact ozone reaction tower having a diameter of 300 mm and a height of 2,700 mm was used. An acid pipe 21 is connected to the lower part of the reaction tank 22 to inject ozone-containing gas into the surfactant-containing water, and the treated water (shear) from the upper part of the reaction tank 22 through the water pipe 23. Side treated water).

The test was conducted under the above conditions, and the surfactant-containing water (shear-side treated water) treated in the shear-side ozone reaction facility 10 was collected at the outlet of the vortex pump 11, and the surfactant concentration of the shear-side treated water was measured. . In addition, the surfactant-containing water (hereinafter, referred to as the final stage treated water) treated in the final stage ozone reaction facility 20 was collected at the outlet of the reactor 22, and the surfactant concentration of the final stage treated water was also measured. The concentration of the surfactant was measured using a spectrophotometer (manufactured by Hitachi Technologies, Inc., F-4500) at an excitation wavelength of 230 nm and a fluorescence wavelength of 305 nm. As a result of the measurement, the surfactant concentration in the front-side treated water was 3.3 mg / L, and the surfactant concentration in the final stage treated water was 0.37 mg / L, and the removal rate of the surfactant was 98.2%. In addition, the gas-liquid interface of the reaction tank 22 was stable and the continuous operation of 2 hours or more was possible.

Comparative Example

As a comparative example, by closing the valve (not shown) provided in the ozone injection tube 12, ozone was not added in the front-side ozone reaction facility 10, and the total amount of ozone was added in the reaction tank 22. As shown in FIG. Specifically, the supply amount of the ozone-containing gas from the acid pipe 21 connected to the reaction tank 22 was 370 L / h. Other conditions were tested similarly to the Example, but the gas-liquid interface of the reactor 22 was disturbed. As a result, the surfactant concentration of the final stage treated water was 2.4 mg / L, and the removal rate of the surfactant decreased to 88.5%. In addition, since the bubble filled in the reaction tank 22 and the gas-liquid interface fell, it was forced to stop a process in about 30 minutes.

As described above, according to the present invention, it is possible to prevent operation troubles of the processing apparatus 1 by foaming and to stably decompose the surfactant at a high decomposition rate.

The present invention can be used for wastewater treatment containing a surfactant.

Claims (7)

A method for treating surfactant-containing water in which ozone is added to surfactant-containing water, wherein the surfactant-containing water flows in a flow path having an inlet and an outlet, and the ozone is contained at a plurality of positions along the flow path. A method of treating surfactant-containing water, which is added to water and adds the most ozone at the position closest to the outlet. The method for treating surfactant-containing water according to claim 1, wherein an alkali is added to the surfactant-containing water before the ozone is added. The method for treating surfactant-containing water according to claim 1, wherein an alkali and hydrogen peroxide are added to the surfactant-containing water before the ozone is added. An apparatus for treating surfactant-containing water, comprising: a passage through which a surfactant-containing water flows from an inlet to an outlet, wherein the ozone is added to the surfactant-containing water flowing along the passage to oxidatively decompose a surfactant. And a plurality of ozone reaction facilities, wherein the final stage ozone reaction facility provided at the position closest to the outlet among the plurality of ozone reaction facilities adds more ozone to the surfactant-containing water than other ozone reaction facilities. Treatment of surfactant-containing water to 5. The final stage ozone reaction facility is a gas-liquid contact reactor having an ozone supply means, and the ozone supply means in the flow path for supplying the ozone to the flow path as the other ozone reaction facility and the surface active in the flow path. An apparatus for treating surfactant-containing water, comprising a stirring reaction facility, which has stirring means for stirring the water. 6. The surfactant-containing surfactant according to claim 4 or 5, further comprising an alkali addition means which is provided at a position close to the inlet from at least one of the plurality of ozone reaction facilities and adds alkali to the surfactant-containing water. Veterinary treatment device. The hydrogen peroxide addition means according to claim 4 or 5, which is provided at a position close to the inlet from at least one of the plurality of ozone reaction facilities, and adds alkali addition means for adding alkali to the surfactant-containing water and hydrogen peroxide addition means for adding hydrogen peroxide. Apparatus for treating surfactant-containing water further comprising.

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