JP2007152185A - Method and apparatus for treating surfactant-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process and an apparatus for treating surfactant-containing water by which foaming by blowing-in of ozone-containing gas is suppressed and stable treatment can be carried out. <P>SOLUTION: The surfactant-containing water is introduced into a flow passage 5 and is made to flow in a direction from an entrance 51 to an exit 52 and ozone is added thereto at two or more positions along a stream of the surfactant-containing water. Addition amount of ozone is largest at a last stage ozone reaction facility 20 arranged at a position nearest the exit 52. When ozone is added at two places, for example at a preceding side ozone reaction facility 10 and the last stage ozone reaction facility 20, about 5 to 40 vol.% of total ozone addition amount is added at the preceding side ozone reaction facility 10 and residual ozone is added at the last stage ozone reaction facility 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for treating surfactant-containing water such as electronic component cleaning wastewater, and more particularly to a method and apparatus for treating surfactant-containing water with ozone gas.

  Conventionally, in semiconductor manufacturing factories and display device manufacturing factories such as liquid crystals, ultrapure water having an extremely low impurity concentration is used as cleaning water for cleaning wafers and the like in the manufacturing process of products. However, cleaning with only ultrapure water may make it difficult to clean fine portions such as wafers due to surface tension. Therefore, in recent years, a method of cleaning a wafer or the like by adding an organic substance such as a surfactant or alcohol to ultrapure water to lower the surface tension has been used.

  For this reason, the waste water discharged | emitted in a semiconductor manufacturing process etc. may contain the surfactant added to the ultrapure water. Known methods for treating surfactant-containing water such as electronic component washing wastewater include activated carbon adsorption, foam separation, chemical decomposition, and biological treatment. Examples of the chemical decomposition method include an ultraviolet irradiation method of irradiating surfactant-containing water with ultraviolet rays, an oxidant addition method of 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 surfactant-containing water to oxidatively decompose the surfactant. Next, an oxidizing agent such as ozone remaining in the treated water is reduced by adding hydrogen.
JP 2000-271577 A

  By the way, as a method for generating ozone, there are a discharge method in which ozone is generated by performing discharge using air or oxygen as a raw material, and an electrolysis method in which ozone is generated by electrolyzing pure water. In the electrolysis method, it is preferable to use ozone generated by the electrolysis method in Patent Document 1 because an ozone aqueous solution having an ozone concentration of about 20% by mass is obtained. However, the ozone that can be generated by the electrolysis method is less than about 1 g / h, and a large amount of ozone cannot be generated by the electrolysis method.

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

  Therefore, in order to oxidatively decompose organic substances such as surfactants contained in the surfactant-containing water, it is necessary to blow a large amount of ozone-containing gas into the surfactant-containing water. For example, when the amount of ozone required to decompose total organic carbon (TOC) contained in surfactant-containing water is 8 times (mass ratio) of TOC, it is necessary for wastewater treatment with a TOC concentration of 20 mg / L. The amount of ozone 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 performs oxidative decomposition with ozone exceeds 1.0, and a large amount of ozone-containing gas is blown into the reaction tank. Foaming occurs.

  In particular, when surfactant-containing water containing a nonionic surfactant as a TOC component is introduced into a reaction tank and ozone-containing gas is blown from an air diffuser provided at the bottom of the reaction tank, severe foaming occurs. As a result, the gas-liquid interface of the reaction tank cannot be stabilized, and troubles such as bubbles flowing out from the waste ozone pipe that discharges the waste ozone-containing gas occur.

  In the present invention, in the ozone treatment of highly foamable surfactant-containing water, the surfactant-containing water treatment method capable of suppressing foaming due to blowing of ozone-containing gas and performing stable treatment, and An object is to provide a processing apparatus.

  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 is allowed to flow through a flow path having an inlet and an outlet, and a plurality of the water is provided along the flow path. A method for treating surfactant-containing water, wherein the ozone is added to the surfactant-containing water at a position and the most ozone is added at a 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 alkali and hydrogen peroxide are added to the surfactant-containing water before adding the ozone.

  (4) A surfactant-containing water treatment apparatus including a flow path through which surfactant-containing water flows from an inlet toward an outlet, the surfactant provided along the flow path and flowing through the flow path It further includes a plurality of ozone reaction facilities that oxidatively decompose the surfactant by adding the ozone to the contained water, and among the plurality of ozone reaction facilities, the final stage ozone reaction facility provided at a position closest to the outlet is An apparatus for treating surfactant-containing water that adds more ozone to the surfactant-containing water than other ozone reaction equipment.

  (5) The final stage ozone reaction facility is a gas-liquid contact type reaction tank having an ozone supply means, and as the other ozone reaction facility, an in-flow path ozone supply means for supplying the ozone to the flow path; The surfactant-containing water treatment apparatus according to (4), further comprising a stirring reaction facility having stirring means for stirring the surfactant-containing water in the flow path.

  (6) The method according to (4) or (5), further including an alkali addition unit that is provided at a position closer to the inlet than at least one of the plurality of ozone reaction facilities and adds an alkali to the surfactant-containing water. Water treatment equipment for surfactants.

  (7) Alkali addition means for adding alkali to the surfactant-containing water and hydrogen peroxide addition for adding hydrogen peroxide, which is provided at a position closer to the inlet than at least one of the plurality of ozone reaction facilities And the surfactant-containing water treatment apparatus according to (4) or (5).

  The liquid to be treated to be treated according to the present invention contains at least a surfactant. The concentration of the surfactant is not particularly limited. For example, the surfactant concentration is 3 to 30 mg / L, and the surfactant contains an organic substance other than the surfactant and has a TOC concentration of about 5 to 50 mg / L. Can be used for water treatment. In particular, the present invention can be used for low TOC concentration wastewater such as electronic component manufacturing factory wastewater. Specifically, the interface has a surfactant concentration of about 1 to 5 mg / L and a TOC concentration of about 2 to 10 mg / L. It can also be applied to activator-containing water.

  In particular, the present invention can be suitably used for the treatment of surfactant-containing water containing a non-ionic surfactant having a strong foaming property, and includes a hardly decomposable surfactant having an ethylene oxide (EO) chain. Suitable for treatment of contained water. However, the type of surfactant is not particularly limited, and the use of the present invention for the treatment of surfactant-containing water containing an anionic surfactant and an ionic surfactant containing a cationic surfactant is not excluded. . Nonionic surfactants include polyoxyethylene alkyl ether (AE), polyoxyethylene alkyl phenyl ether (APE), fatty acid alkanolamide, and polyoxyethylene sorbitan fatty acid ester.

  Although ozone can be added to the surfactant-containing water as an ozone-containing gas produced using air or oxygen as a raw material, the use of ozone produced by an electrolytic method is not excluded. The amount of ozone added is preferably an amount necessary for completely decomposing the surfactant into carbon dioxide (hereinafter referred to as “complete decomposition required amount”). However, depending on the reaction efficiency, ozone exceeding the amount required for complete decomposition may be added. After performing the treatment according to the present invention, complete decomposition is required when performing biological treatment, adsorption treatment, deionization treatment, etc. The addition amount may be less than the amount.

  Specifically, when the surfactant is completely decomposed to carbon dioxide, the amount of ozone added is preferably 20 to 50 times (mass ratio) with respect to the surfactant. When biological treatment is performed after the treatment according to the present invention, the amount of ozone added is 2 to 10 times (mass ratio) with respect to the surfactant, so that the surfactant can be biodegraded, that is, organic acids or glycols. It is preferable to decompose to.

  In the present invention, ozone necessary for decomposing the surfactant is divided and added at a plurality of positions along the flow direction of the surfactant-containing water flowing in a certain direction, and particularly at the final stage, that is, at the outlet. Add the most ozone in the close position. The amount of ozone added in the final stage is preferably 60 to 95% of the total amount added. In the present invention, since the ozone addition position is divided into a plurality, depending on the reaction efficiency, etc., the amount of ozone added in the final stage may be larger than the preset amount, or conversely, Good.

  The ozone addition position may be two or more. When the ozone addition position is two, ozone is added at 5 to 40% of the total addition amount before the final stage, that is, at the first ozone addition position. To do. Moreover, when the ozone addition position is three or more, the ozone addition amounts at a plurality of ozone addition positions other than the final stage may be the same or different. While there are many ozone addition positions, the decomposition rate of the surfactant can be improved. On the other hand, equipment required for ozone addition increases, and therefore the ozone addition positions are preferably two to three.

  According to the present invention, if the ozone addition position necessary for the decomposition of the surfactant is divided into a plurality of locations along the flow of the surfactant-containing water, it is one location compared to the case where ozone is added at one location. Since the amount of ozone added per unit is reduced, foaming can be suppressed. In particular, in the present invention, most of the total addition amount is added at the final stage closest to the outlet of the surfactant-containing water flow path, and the ozone addition amount at the inlet side, that is, the front stage side is smaller than the final stage. By doing so, it is possible to obtain high ozonolysis efficiency while suppressing foaming.

  This is because a small amount of ozone added on the inlet side reacts easily and quickly with the surface activity of the surfactant (the boundary between the hydrophobic portion and the hydrophilic portion). It is assumed that it is denatured. That is, first, since the foaming property is reduced by modifying the surfactant with a small amount of ozone added at the inlet side, it is considered that foaming can be suppressed even if a large amount of ozone is added in the final stage. .

  At the ozone addition position, an ozone reaction facility for reacting ozone with the surfactant by adding ozone to the surfactant-containing water is provided. The ozone reaction equipment only needs to include an ozone supply means for adding ozone to the surfactant-containing water. However, in order to sufficiently react ozone with the surfactant, the surfactant-containing water can stay for a predetermined time. It is preferable to further comprise a reaction vessel. In particular, the ozone reaction facility (final stage ozone reaction facility) provided at the position closest to the outlet of the flow path through which the surfactant-containing water flows is used to secure the reaction time between the surfactant and ozone. It is preferable to provide a gas-liquid contact type reaction tank having ozone supply means.

  On the other hand, since the surface activity of the surfactant has a high reaction rate with ozone, the ozone reaction facility (hereinafter referred to as the “previous stage ozone reaction facility”) provided on the inlet side of the final stage ozone reaction facility The ozone supply means in the flow path for adding ozone to the surfactant flowing in the flow path may include at least an ozone supply pipe, an ejector, a perforated pipe, and a vortex with an air supply port. Pumps, etc. The former stage ozone reaction equipment, in particular, stirs 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. The stirring means preferably includes a vortex pump capable of aeration operation, a line mixer, etc. In this way, the front-stage ozone reaction equipment is not suitable. The apparatus by omitting the bath can be simplified.

  In the present invention, in order to promote the oxidation reaction by ozone, an alkali is added before adding ozone to the surfactant-containing water, and ozone is added to the surfactant-containing water in the presence of the alkali. Also good. The amount of alkali added is preferably an amount necessary to adjust the pH of the surfactant-containing water to 9-11. The kind of alkali to add is not specifically limited, Sodium hydroxide, potassium hydroxide, etc. can be used.

  In addition to alkali, hydrogen peroxide may also be added to the surfactant-containing water. When alkali and hydrogen peroxide are added to the surfactant-containing water before the addition of ozone, the order of addition of alkali and hydrogen peroxide is not particularly limited. Further, the amount of alkali added may be the same as in the case where hydrogen peroxide is not added, and the amount of hydrogen peroxide added is preferably about 0.1 to 1 by mass ratio with respect to the amount of ozone added.

  As described above, after adding alkali alone or together with hydrogen peroxide to the surfactant-containing water, by adding ozone, hydroxyl radicals can be generated to promote the oxidation reaction. Alkaline (and hydrogen peroxide) may be added prior to ozone addition at at least one of the ozone addition positions divided into a plurality of positions, but may be added before each ozone addition position. In particular, in order to improve the production efficiency of hydroxyl radicals, 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 tank is not limited, and it is preferable to have a configuration in which an ozone-containing gas is supplied to the surfactant-containing water from the lower part of the reaction tank and the waste ozone-containing gas is taken out from the upper part of the reaction tank. Further, the water to be treated may be supplied from the lower part of the reaction tank, or a watering means may be provided at the upper part of the reaction tank, and the water to be treated may be supplied from the watering means. Thus, if it sprays on a liquid level, it will be easier to suppress foaming.

  According to the present invention, it is possible to add a necessary amount of ozone to suppress foaming of surfactant-containing water and oxidatively decompose the surfactant. For this reason, according to this invention, surfactant can be decomposed | disassembled with a high decomposition rate, the trouble by foaming can be prevented, and surfactant-containing water can be processed stably.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Hereinafter, the same members are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 1 is a schematic view of a surfactant-containing water treatment apparatus (hereinafter simply referred to as “treatment apparatus”) 1 according to an embodiment of the present invention. The treatment apparatus 1 includes a flow path 5 through which a surfactant-containing water containing a surfactant to be treated flows, a front-stage ozone reaction facility 10 provided in the middle of the flow path 5, and a final-stage ozone reaction facility 20. And including. The flow path 5 includes an inlet 51 and an outlet 52, and the surfactant-containing water is introduced into the processing apparatus 1 from the inlet 51 so as to flow from the inlet 51 toward the outlet 52, and is discharged from the outlet 52.

  In the present embodiment, the first hydrogen peroxide addition means and the first alkali addition means are provided on the inlet 51 side from the front-stage ozone reaction facility 10. Further, a second hydrogen peroxide addition unit and a second alkali addition unit 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 can be omitted.

  The hydrogen peroxide addition means can be constituted by a member capable of adding hydrogen peroxide to the surfactant-containing water flowing in the flow path 5, for example, a pipe having one end connected to a storage tank storing hydrogen peroxide. . In the present embodiment, the first hydrogen peroxide addition means is constituted by the first hydrogen peroxide injection pipe 31, and the second hydrogen peroxide addition means is constituted by the second hydrogen peroxide injection pipe 32. Each of the first hydrogen peroxide injection pipe 31 and the second hydrogen peroxide injection pipe 32 has one end connected to the hydrogen peroxide storage tank 30 and the other end connected to a pipe constituting the flow path 5.

  The alkali addition means can be constituted by a member capable of adding alkali to the surfactant-containing water flowing in the flow path 5, and can be, for example, a pipe connected at one end to a storage tank storing the alkali. In the present embodiment, the first alkali addition means is constituted by a first alkali injection pipe 41, and the second alkali addition means is constituted by a second alkali injection pipe 42. One end of each of the first alkali injection pipe 41 and the second alkali injection pipe 42 is connected to the alkali storage tank 40, and the other end is connected to a pipe constituting the flow path 5.

  The front-stage ozone reaction facility 10 includes a vortex pump 11 as stirring means provided in the middle of the flow path 5 and an in-flow path ozone supply means connected to the flow path 5 on the inlet 51 side from the vortex pump 11. Has been. In the present embodiment, the ozone supply means in the flow path can be constituted by a member that blows ozone-containing gas into the flow path 5. For example, in this embodiment, the ozone supply means is constituted by an ozone injection pipe 12 having one end connected to the flow path 5. Yes. The other end of the ozone injection pipe 12 is connected to the ozone generator 25.

  The final stage ozone reaction facility 20 is a gas-liquid contact type reaction tank 22 having a sprinkling pipe 23 as supply water (treated water from the preceding ozone reaction equipment 10) supply means and a diffusion pipe 21 as ozone supply means. It is configured. One end of the air diffuser 21 is connected to the ozone generator 25, and the ozone-containing gas generated by the ozone generator 25 is added to the surfactant-containing water from the lower part of the reaction tank 22 through the air diffuser 21. Although the size of the reaction tank 22 is not particularly limited, it is preferable that the residence time of the surfactant-containing water is set to be a time necessary for the surfactant to be oxidatively decomposed by ozone. The residence time of the agent-containing water is preferably 5 to 10 minutes.

  In the present embodiment, the ozone-containing gas generated by the ozone generator 25 is supplied to the ozone injection pipe 12 and the diffuser pipe 21 via the ozone path 25A. Particularly in the present invention, most of the ozone-containing gas (about 60 to 95%) added to the surfactant-containing water is added to the surfactant-containing water from the final stage ozone reaction facility 20. For this reason, most of the ozone containing gas produced | generated with the ozone generator 25 is supplied to the diffuser pipe 21, and the ozone injection pipe 12 is comprised so that about 5-40% of the produced | generated ozone containing gas may be supplied. Has been.

  Next, a method for treating surfactant-containing water using the treatment apparatus 1 will be described. First, surfactant-containing water such as semiconductor manufacturing wastewater is introduced into the flow path 5 from the inlet 51 as a liquid to be treated. A pump or the like is provided in the middle of the channel 5 so that the surfactant-containing water can flow through the channel 5 at a flow rate of about 0.5 to 2 m / sec from the inlet 51 side toward the outlet 52 side. It is good to make it flow.

  In the processing apparatus 1 according to the present embodiment, the first hydrogen peroxide injection pipe 31, the first alkali injection pipe 41, the ozone injection pipe 12, and the vortex pump along the flow path 5 from the inlet 51 side toward the outlet 52 side. 11, a second hydrogen peroxide injection pipe 32, a second alkali injection pipe 42, and a reaction tank 22 are provided in this order. Then, in the surfactant-containing water flowing in the direction from the inlet 51 side toward the outlet 52 side, first, hydrogen peroxide from the first hydrogen peroxide injection pipe 31 and the first alkali injection pipe 41 along the flow direction. Then, alkali such as sodium hydroxide 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 whose pH has been raised. A vortex pump 11 is provided immediately after the ozone injection pipe 12, and the surfactant-containing water to which a small amount of ozone is added is stirred by the vortex pump 11. Since it is sufficient that a small amount of ozone can be added to the upstream ozone reaction facility 10, the vortex pump 11 may be omitted. Further, 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. In this way, the surfactant-containing water to which a small amount of ozone is added in the front-stage ozone reaction facility 10 is stirred with the vortex pump 11 to give a large shearing force, so that a small amount of ozone can be efficiently combined with the surfactant. Can be reacted.

  In the front-stage ozone reaction facility 10, the surfactant is denatured by adding a small amount of ozone, and foaming properties are reduced. This is presumably because ozone added in a small amount mainly reacts with the boundary portion between the hydrophobic portion and the hydrophilic portion of the surfactant, and the portion showing the surface activity of the surfactant is denatured. . For this reason, even if a large amount of ozone is added in the final stage ozone reaction facility 20, foaming of the liquid to be treated can be suppressed. Therefore, in the present invention, about 5 to 40% of the total ozone amount added to the surfactant-containing water in the processing apparatus 1 is added in the front stage ozone reaction facility 10, and the remaining amount in the final stage ozone reaction facility 20. Add ozone.

  Since the surfactant is denatured by the reaction between ozone and the surfactant and an organic acid or the like is generated, the second hydrogen peroxide injection pipe 32 and the second hydrogen peroxide injection pipe 32 are disposed in the processing apparatus 1 before the final stage ozone reaction facility 20. An alkali injection pipe 42 is provided. Thus, hydrogen peroxide and alkali are added to the surfactant-containing water that has passed through the front-stage 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 liquid to be treated (surfactant-containing water) is introduced into the reaction tank 22, and an ozone-containing gas is blown from a diffuser tube 21 connected to the lower part of the reaction tank 22, thereby supplying the liquid to be treated to a predetermined level. It stays in the reaction tank 22 for a time. In the final stage ozone reaction facility 20, most of the total ozone amount (about 60 to 95%) added to the surfactant-containing water in the treatment apparatus 1 is added to the liquid to be treated to decompose the surfactant. After the treatment in the final stage ozone reaction facility 20, the treated water in which the surfactant is decomposed is taken out from the outlet 52, and after-treatment such as biological treatment is performed as necessary, and can be used as raw water for producing ultrapure water. .

[Example]
Hereinafter, the present invention will be described in more detail based on examples. As an example, the treatment apparatus 1 shown in FIG. 1 was used, and a surfactant-containing water containing APE as a surfactant was used as a liquid to be treated. The surfactant-containing water is a synthetic wastewater prepared by dissolving APE in pure water so as 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 is used, and the surfactant-containing water flows in the flow path 5 from the inlet 51 to the outlet 52 at a flow rate of 350 L / h. Was introduced into the processing apparatus 1.

  In this example, hydrogen peroxide and alkali were added prior to the addition of ozone in each ozone reaction facility. Hydrogen peroxide having a concentration of 35% by mass was used, and 4% by mass of sodium hydroxide was used as the alkali. The amount of hydrogen peroxide added was 15 mg / L from the first hydrogen peroxide injection tube 31 and 250 mg / L from the second hydrogen peroxide injection tube 32. The second hydrogen peroxide injection pipe 32 is configured differently from the processing apparatus 1 of FIG. 1 in that it is connected to the lower part 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 first alkali injection pipe 41 and the second alkali injection pipe 42. The amount of sodium hydroxide added was such that the pH of the surfactant-containing water was 10.

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

  As the reaction tank 22, a cylindrical gas-liquid contact type ozone reaction tower having a diameter of 300 mm and a height of 2,700 mm was used. A diffuser pipe 21 is connected to the lower part of the reaction tank 22 and ozone-containing gas is blown into the surfactant-containing water, and water to be treated (previous-stage treated water) is sprinkled from the upper part of the reaction tank 22 through the sprinkler pipe 23. .

  The test was performed under the above conditions, and the surfactant-containing water treated in the front-stage ozone reaction facility 10 (the front-stage treated water) was collected at the outlet of the vortex pump 11 and the surfactant concentration of the front-stage treated water was measured. . Moreover, the surfactant containing water (henceforth the last stage treated water) processed by the last stage ozone reaction equipment 20 was extract | collected at the reaction tank 22 exit, and the surfactant density | concentration of the last stage treated water was also measured. The concentration of the surfactant was measured using a spectrofluorometer (manufactured by Hitachi High-Technologies Corporation, F-4500) at an excitation wavelength of 230 nm and a fluorescence wavelength of 305 nm. The measurement results showed that the surfactant concentration in the front-stage treated water was 3.3 mg / L, the surfactant concentration in the final-stage treated water was 0.37 mg / L, and the surfactant removal rate was 98.2%. It was. Moreover, the gas-liquid interface of the reaction tank 22 was stable, and continuous operation for 2 hours or more was possible.

[Comparative example]
As a comparative example, by closing a valve (not shown) provided in the ozone injection pipe 12, the total ozone amount was added in the reaction tank 22 without adding ozone in the front-stage ozone reaction facility 10. Specifically, the supply amount of the ozone-containing gas from the air diffuser 21 connected to the reaction tank 22 was set to 370 L / h. When the test was conducted under the same conditions as in the example, the gas-liquid interface of the reaction tank 22 was disturbed. As a result, the surfactant concentration in the final stage treated water was 2.4 mg / L, and the surfactant removal rate decreased to 88.5%. Further, since the reaction tank 22 was filled with bubbles and the gas-liquid interface was lowered, the treatment had to be stopped in about 30 minutes.

  Thus, according to the present invention, it is possible to prevent the operation trouble of the processing apparatus 1 due to foaming and to stably decompose the surfactant at a high decomposition rate.

  The present invention can be used for treatment of waste water containing a surfactant.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 5 Flow path 10 Previous stage ozone reaction equipment 11 Eddy current pump 12 Ozone injection pipe 20 Final stage ozone reaction equipment 21 Aeration pipe 22 Reaction tank 23 Sprinkling pipe 25 Ozone generator 25A Ozone path 31 1st hydrogen peroxide injection pipe 32 Second hydrogen peroxide injection pipe 41 First alkali injection pipe 42 Second alkali injection pipe 51 Inlet 52 Outlet

Claims (7)

A method for treating surfactant-containing water by adding ozone to the surfactant-containing water,
The surfactant-containing water is caused to flow through a flow path having an inlet and an outlet, and the ozone is added to the surfactant-containing water at a plurality of positions along the flow path. A method for treating surfactant-containing water to which ozone is added.   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. A surfactant-containing water treatment apparatus including a flow path through which surfactant-containing water flows from an inlet toward an outlet,
A plurality of ozone reaction facilities that are provided along the flow path and oxidatively decompose the surfactant by adding the ozone to the surfactant-containing water flowing through the flow path;
Of the plurality of ozone reaction facilities, the final stage ozone reaction facility provided at a position closest to the outlet includes a surfactant that adds more ozone to the surfactant-containing water than other ozone reaction facilities. Water treatment equipment. The final stage ozone reaction facility is a gas-liquid contact type reaction tank having ozone supply means,
The other ozone reaction facility includes an agitation reaction facility having an in-channel ozone supply unit that supplies the ozone to the channel and an agitation unit that agitates the surfactant-containing water in the channel. Item 5. A surfactant-containing water treatment apparatus according to Item 4.   The surfactant-containing composition according to claim 4 or 5, further comprising an alkali adding means that is provided at a position closer to the inlet than at least one of the plurality of ozone reaction facilities and adds an alkali to the surfactant-containing water. Water treatment equipment.   Provided at a position closer to the inlet than at least one of the plurality of ozone reaction facilities, an alkali adding means for adding alkali to the surfactant-containing water, and a hydrogen peroxide adding means for adding hydrogen peroxide, The surfactant-containing water treatment apparatus according to claim 4 or 5, further comprising:

Images