JP2002292379A - Method and device for accelerated oxidation treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for accelerated oxidation treatment, by which a high removal rate of organic substances can be obtained with a reduced amount of ozone and by which ozone can be used efficiently even when the organic substance content in water varies. SOLUTION: This accelerated oxidation treatment device is provided with an oxidation reaction means for oxidizing the organic substances having a reactor filled with the water and a fine bubble generating means for dissolving ozone in the water, a dissolved gas removing means, a TOC concentration measuring part, an ozone concentration measuring part, and an oxidation reaction control means which controls the ozone concentration measuring part and/or the TOC concentration measuring part, and at the same time, controls the circulation of the water based on the inputted measurement results so that untreated water is mixed with the water from the reactor or the dissolved gas removing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accelerated oxidation reaction method and apparatus using ozone, and more particularly, to an efficient method of reducing the amount of ozone used in wastewater containing organic substances generated in a semiconductor or liquid crystal manufacturing process. The present invention relates to an accelerated oxidation treatment method and apparatus capable of performing an oxidation treatment.

[0002]

2. Description of the Related Art Today, global demands for effective use of resources have been increasing from the standpoint of environmental protection of the earth, and there has been an increasing movement to reuse water in semiconductors and liquid crystal factories that have consumed large amounts of water. is there.

[0003] In the production process of semiconductors and liquid crystals, a large amount of organic solvents are used for removing photoresists and the like.
Examples of the organic substance to be used include IPA (isopropyl alcohol), DMSO (dimethyl sulfoxide), TMAH (tetramethylammonium hydroxide), and acetone, and it is necessary to remove these organic substances from the wastewater.

In recent years, a method using ozone has been widely used as one of means for removing organic substances. However, the use of ozone alone alone is often inefficient, and studies have been made in various fields using the accelerated oxidation technology described below.

[0005] The accelerated oxidation treatment is defined as a technique for powerful purification of water including generation of OH radicals (hydroxyl radicals). Among the advanced oxidation treatment techniques, the simplest and most practical method used in actual plants is a method using ozone and hydrogen peroxide in combination (ozone + H ₂ O ₂ method) or a high pH value of ozone and alkaline. This is an adjustment method (ozone + high pH adjustment method). The difference between the two is whether hydrogen peroxide is injected or not, which is the same in that the pH is adjusted to each appropriate value.

[0006] When the purpose of reusing semiconductor wastewater is to evaluate the ability to reduce organic substances by the ozone oxidation treatment, the ozone oxidation treatment is not used alone, but the ozone oxidation treatment and the ion exchange removal treatment (MB: And mixed-bed type ion exchange resin) to evaluate the ability to reduce organic matter. T
Using an OC (total organic carbon) meter or the like, the concentration of organic substances before and after the treatment is compared, and the degree of reduction of the organic substances is expressed as a removal rate. In the ozone oxidation reaction, organic acids that could not be decomposed to inorganic carbon (inorganic carbonic acid) remain,
Since these organic acids are ions, they can be easily removed by a device installed at a later stage such as an ion exchange resin.
Therefore, as a method for evaluating the decomposition of organic substances due to the oxidation reaction, an ion exchange removal treatment is performed after the ozone oxidation treatment to remove the organic acid generated after the reaction, thereby decomposing the organic matter in the reaction tank. It is a reasonable method that fits the actual purpose.

As a reaction tank, a method of generating air bubbles of an ozone-containing gas from the lower part of the reaction tank is generally used. 2000-167366). As means for generating air bubbles, an aerator system that introduces gas by a diffuser or rotating blades, an ejector system that uses a venturi, or a swirl system that swirls a liquid like a cyclone and introduces gas from the center Fine bubble generation method (Japanese Patent Publication No. 8-154531,
000-47), or a U-tube method using a diffuser tube bent in a U-shape.

As the ozone generator, a device that generates ozone by silent discharge is usually used. In this silent discharge, ozone is generated by passing a source gas through an ozone generator and applying an AC voltage to perform discharge. Other examples of the ozone generator include an electrolysis system, a photochemical system, a chemical reaction system, an ultraviolet irradiation system, and a high-frequency electric field system. Further, since the ozone generator generates heat by electric discharge, an apparatus having a cooler is usually used.

In order to remove the ozone remaining in the exhaust gas, an exhausted ozone gas treatment device decomposes and removes ozone with a catalyst resin or the like and discharges it into the atmosphere. As raw material gas, in addition to pure oxygen, those using liquid oxygen,
A gas in which air is used as a raw material to generate a gas having an oxygen concentration of 80% or more by a raw material gas pretreatment device is used.

As shown in the following graph 1, the optimum pH based on the removal rate of organic substances in the accelerated oxidation reaction is pH 10 and ozone + H ₂ in the ozone + high pH adjustment method.
The O ₂ system is pH7. The optimum pH is almost constant without being affected by the amount of the ozone-containing gas supplied to the reaction tank. Therefore, in the case of the ozone + high pH adjustment method, the pH is adjusted to 10 to 10 at the outlet of the reaction tank.
It is adjusted to maintain about 11. Also, ozone +
In the case of the H ₂ O ₂ method, the pressure is adjusted so as to be maintained at around 7 to 8 at the outlet of the reaction tank. When the organic matter is oxidized, an organic acid and carbonic acid are produced as reaction products, and as a result, the pH becomes acidic. Therefore, pH adjustment is performed by injecting an alkali such as NaOH into the inlet of the reaction tank or the reaction tank.

[Graph 1]

In many cases, an oxidizing agent removing device is installed downstream of the reaction tank. The remaining ozone or H ₂ O ₂ is removed by the oxidizing agent removing device. As the oxidizing agent removing means, there are a method of using a catalytic resin carrying activated carbon or a metal, ultraviolet irradiation, or a reducing agent. The ozone ₊ H 2 _{O 2} method, the _H 2 _{O 2} in the reaction vessel outlet at least 5~10ppm
To the extent that the oxidizing agent remains to a certain extent, an oxidizing agent removing device or a device equivalent thereto is provided for protection of a device that is vulnerable to an oxidizing agent, such as an ion exchange resin or a reverse osmosis membrane, which is installed at a later stage.

However, in the case of the ozone + high pH adjustment method,
Depending on the processing conditions, the residual
Dzon concentration is reduced. Therefore, it is not always necessary to remove the oxidizing agent
No equipment is required, and even if installed, ozone + H
₂O₂Oxidant load to be removed compared to the method
Is less. This is because high alkali conditions in the reaction vessel
It can be considered that it plays the role of an oxidizer removal device.
You. Also, ozone + H ₂O₂In the system, H₂O₂
Reduce the amount of addition and adjust the pH to a high alkaline range.
The reaction efficiency is slightly reduced, but oxidizing agent removal means is installed.
There is also a method to carry out without. These things apply
Since this is a problem related to the design of the entire water treatment facility,
The best one has been selected.

[0013]

In a conventional accelerated oxidation reactor utilizing ozone, the efficiency of use of ozone in a reaction tank is poor, and a large amount of ozone is consumed. Therefore, the ozone generator is relatively expensive, which is not economically preferable. Further, the higher the removal rate is expected, the more the ozone utilization rate tends to be significantly deteriorated. In this case, there is a problem that most of the ozone is not used for the reaction and remains as exhaust gas.

On the other hand, with the recent miniaturization of LSIs and ULSIs, the demand for the purity of pure water used in the production thereof has been increasing. However, it has been difficult to achieve an improvement in ozone utilization efficiency while achieving both a reduction in the amount of ozone used and a high removal rate.

Further, as means for improving the ozone utilization efficiency, there is provided a circulation channel for circulating the liquid to be treated oxidized in the reaction tank for oxidizing treatment so as to be mixed with the untreated water to be treated. Recirculation of treated water, or
2. Description of the Related Art There is a multistage reaction tank type apparatus having a plurality of oxidation treatment reaction tanks, and continuously transferring water to be treated from one reaction tank to another reaction tank to react in multiple stages. In the treated water circulation system,
By providing the circulation channel, the chance of contact between the liquid to be treated and the liquid gas is increased, so that the efficiency of the ozone oxidation reaction can be improved.

In the case of the multi-stage reaction tank system, there is a drawback that the scale of the apparatus becomes large and the equipment cost increases, but the greatest advantage is that it is easy to reuse the ozone remaining in the exhaust gas. . For example, if the ozone gas used in the previous reaction tank still has enough ozone,
It can be reused in the subsequent reaction tank.

However, simply using these methods may have some effects, but at present it does not lead to a large reduction in ozone consumption. Further, the accelerated oxidation treatment apparatus is usually designed so as to conform to the maximum possible concentration of the organic matter contained in the raw water to be treated. When the concentration of organic substances in the water to be treated fluctuates in the treatment using such an apparatus, particularly when the concentration fluctuates to a low concentration, exhaust gas containing high-concentration ozone is generated, and it becomes difficult to efficiently use ozone. Not only that, there is a problem that a high load is imposed on the exhaust ozone gas treatment means in the subsequent stage.

Accordingly, the present invention has been made in view of the above-described problems, and it is possible to obtain a high organic matter removal rate by minimizing a necessary amount of ozone, and to obtain an organic matter-containing material in the water to be treated. An object of the present invention is to provide a method and an apparatus for promoting oxidation treatment using ozone, which can be controlled to use ozone efficiently even when the amount fluctuates.

[0019]

In order to achieve the above-mentioned object, the present inventor has proposed a method for reducing organic matter in an accelerated oxidation reaction using ozone in combination with a carbon dioxide removal treatment (such as a deaerator for retaining water to be treated). The ability was examined repeatedly. As a result, it has been found that, first, the setting of the removal rate for nonionic organic matters has a great significance for the utilization efficiency of ozone in the accelerated oxidation treatment. In other words, by providing a reaction tank for oxidizing treatment in the circulation path of the water to be treated or in multiple stages, and appropriately arranging and using dissolved gas removing means for removing carbon dioxide in the water to be treated, the nonionic The reason is that the removal rate of organic substances is set to be low, and a high removal rate can be achieved in the entire apparatus.

The oxidation reaction process in the accelerated oxidation treatment of organic substances will be described using IPA as an example. IPA is a substance that is often used in a semiconductor cleaning process and the like, and is largely contained in wastewater that is raw water to be treated. The reaction until IPA is oxidized and decomposed to carbonic acid is generally considered to be as follows. _{C 3 H 8 O (IPA)} + [O] ⇒ C 3 H 6 O ( _{acetone) + H 2 O C 3 H} 6 O ( _{acetone) +3 [O] ⇒ CH 3} COOH
(Acetic acid) + CH ₂ O ₂ (formic acid) CH ₃ COOH + CH ₂ O ₂ (formic acid) +3 [O] ⇒
3CO ₂ + 3H ₂ O

[0021] Actual wastewater contains various kinds of organic substances, and the oxidation reaction process in the accelerated oxidation treatment of organic substances is considerably complicated. Here, the following simple division is given to this complicated reaction system. Introduce. That is, nonionic organic substances (IPA and acetone in the IPA reaction), organic acids (acetic acid and formic acid in the IPA reaction), inorganic carbonic acid (CO2)
₂ , HCO ₃ ⁻ , CO ₃ ²⁻ ), and the reaction is classified into two types: organic acids from nonionic organic substances, and carbonic acids from organic acids. These two kinds of reactions proceed by the ozone oxidation reaction, but it is generally known that the progress from the organic acid to the inorganic carbon is difficult to proceed.

In the accelerated oxidation treatment, the results of Test Example 1 showing the progress of the oxidation reaction with respect to the ozone supply amount, which is the product of the supply flow rate of the ozone-containing gas supplied to the reaction tank and the ozone concentration, are shown in graph 2. Here, ozone-containing gas having an ozone concentration of 120 g / Nm ³ is supplied at different supply flow rates to supply ozone using raw water to be treated containing IPA having a carbon concentration of 20 ppm, and the latter stage of the ozone oxidation reaction in the reaction tank. The ion exchange removal treatment was performed. At the outlet of the reaction vessel, the proportions of nonionic organic substances, organic acids, and inorganic carbons are shown by carbon (carbon: C) concentrations. The C concentrations at the reaction tank inlet, the reaction tank outlet and the MB outlet were measured with a TOC meter, and [reaction tank inlet-reaction tank outlet] was inorganic carbonic acid, [reaction tank outlet-MB outlet] was organic acid, and [reaction tank inlet]. -MB outlet] as nonionic organic matter.

[Graph 2]

Similarly, the carbon concentration is about 20 ppm
Using the raw water containing IPA, the concentration of IPA at the outlet of the reaction tank was about 2 ppm, 4 ppm, and 7 pp, respectively.
An accelerated oxidation treatment was carried out so as to obtain an m and 14 ppm. The results in Test Example 2 were evaluated based on the ozone concentration, the ozone input amount (ΔO ₃ / ΔTOC), and the ozone consumption amount (ΔO ₃ /) in the exhaust gas discharged through the water to be treated and discharged on the liquid surface in the reaction tank.
It is shown in Table 1 as (ΔTOC).

[Table 1]

Test Example 1 shows that even if sufficient ozone is supplied, many IPAs remain in the form of organic acids. Briefly, the oxidation reaction by ozone proceeds efficiently from nonionic organic substances to organic acids.
One reason that the reaction from the organic acid to the inorganic carbon is difficult to proceed is that the carbonate ion as a reaction product becomes a scavenger in the ozone oxidation reaction. That is, the carbonate ion is a factor that inhibits the oxidation reaction of the organic substance by ozone. When a large amount of carbonate ions are present in the raw water to be treated, a method of reducing the concentration of carbonate ions may be adopted, such as adjusting the pH before the accelerated oxidation reaction and degassing as CO ₂ . However, when a relatively high concentration of organic matter is oxidized and decomposed by an ozone oxidation reaction to a low concentration level, a carbonate ion as a reaction product greatly delays the progress of the reaction, and the more the oxidation reaction by ozone proceeds, the more the oxidation proceeds. As a result, the carbonate ion concentration increases, and the amount of ozone required to process the organic matter concentration per unit increases.

As shown in Table 1, at the inlet of the reactor, about 2
When IPA having a TOC concentration of 0 ppm is reduced to 6.8 ppm, ozone supplied to the reactor at a concentration of 120 g / N · m ³ is 1 g / N · m ^{3 in the} exhaust gas.
Has decreased to However, 3.9 ppm, 2p
When it is reduced to pm, the ozone concentration in the exhaust gas is increasing. On the other hand, the ozone amount required for removing the unit IPA hardly changes between 6.8 ppm and 3.9 ppm. In other words, the more the IPA concentration is reduced to a lower concentration, the more ozone not involved in the reaction is present, resulting in a significant decrease in ozone utilization efficiency from the viewpoint of the input ozone amount.

Carbonic acid and hydrogen carbonate ions produced in the water to be treated in the oxidation reaction of the accelerated oxidation treatment with ozone and serving as scavengers can be removed by ion exchange together with the organic acid, but the pH of the water to be treated is adjusted. By doing so, it can be removed as carbon dioxide (CO ₂ ). Inorganic carbonic acid in water is present in three types: carbon dioxide (CO ₂ ), bicarbonate ion (HCO ₃ ⁻ ), and carbonate ion (CO ₃ ²⁻ ), and the abundance ratio of each is as shown in the following graph 3. PH. Therefore, the water to be treated can be removed as CO ₂ by adjusting the pH of the water to be treated to 5.5 or less and degassing without performing the ion exchange removal. An oxidation reaction can be performed.

[Graph 3]

In order to achieve the above-mentioned object based on such findings, the present invention provides a water-containing organic substance to which a pH adjuster or a pH adjuster and hydrogen peroxide are added, and an accelerated oxidation reaction using ozone. In an accelerated oxidation treatment method for treating water to be treated by supplying an ozone-containing gas to a reaction tank filled with the water to be treated, generating fine bubbles of the supplied ozone-containing gas to dissolve ozone in the water to be treated. At least one oxidation reaction step of oxidizing organic substances in the water to be treated by the method, and one or more dissolved gas removing steps of removing inorganic carbonic acid in the water to be treated as carbon dioxide gas by degassing the water to be treated; The TOC concentration of the untreated water and / or the water to be treated that has passed at least the oxidation reaction step and / or the ozone concentration of the ozone-containing gas discharged onto the liquid surface of the water to be treated in the reaction tank are determined as follows. Constant and, based on the measurement results, and controlling the flow of the water to be treated via at least the oxidation reaction step with the water to be treated untreated.

In the above-mentioned accelerated oxidation treatment method, in the dissolved gas removing step, the water to be treated whose pH has been adjusted to 5.5 or less is retained in a retention tank for a predetermined time and degassed, thereby removing inorganic carbonic acid in the water to be treated. It is preferable to remove the water as a carbon dioxide gas. The water to be treated, whose pH has been adjusted to 5.5 or less, is dropped from the top and dropped, and is sent to a degassing tower that blows from the bottom to be degassed. The inorganic carbonic acid in the treated water may be removed as carbon dioxide. Further, in the dissolved gas removing step, the water to be treated, whose pH has been adjusted to 5.5 or less, is dropped from the top and lowered, and is sent to a vacuum degassing tower for degassing the inside of the tower from the top and degassing. In this way, it is possible to remove inorganic carbonic acid in the water to be treated as carbon dioxide gas. Further, the water to be treated, whose pH has been adjusted to 5.5 or less, is removed by a gas-permeable and water-impermeable membrane. The inorganic carbonic acid in the water to be treated may be removed as carbon dioxide gas by sending the water to a membrane deaerator for liquid separation and degassing.

In such a dissolved gas removing step, it is preferable to remove, at a later stage of the oxidation reaction step, at least the inorganic carbonic acid in the water to be treated that has undergone the oxidation reaction step as carbon dioxide gas. Of the treated water that has passed, the inorganic carbonic acid in the treated water circulating so as to be mixed with the untreated water may be removed as carbon dioxide gas, and the untreated treated water may be removed before the oxidation reaction step. The inorganic carbonic acid in the water to be treated or a mixture of the water to be treated and the water to be treated which has undergone at least the oxidation reaction step may be removed as carbon dioxide.

In the above-mentioned accelerated oxidation treatment method,
The control of the flow of the water to be treated is performed by measuring the untreated water to be treated and / or at least the T of the water to be treated after the oxidation reaction step.
TOC concentration for determining the TOC concentration level of untreated water to be treated and / or at least water to be treated which has undergone an oxidation reaction step by comparing the magnitude of the measured OC concentration value with a plurality of TOC concentration reference values arbitrarily set in advance. Exhaust gas for determining the exhaust gas ozone concentration level by comparing the measured ozone concentration value in the discharged ozone-containing gas and / or a plurality of arbitrarily preset exhaust gas ozone concentration reference values in a level determination step and / or An ozone concentration level judging step; an untreated water that has been subjected to at least an oxidation reaction step with respect to a flow rate of the untreated water that is arbitrarily set in advance according to the TOC concentration level and / or the exhaust gas ozone concentration level; It is preferable to control the circulation of the water to be treated based on a circulation ratio which is a ratio of a circulation flow rate circulating so as to be mixed with the water to be treated.

Here, the circulation ratio is preferably set so as to decrease as the TOC concentration level determined in the TOC concentration level determination step goes from the high concentration level side to the low concentration level side. The circulation ratio may be set to increase as the exhaust gas ozone concentration level determined in the ozone concentration level determination step goes from the high concentration level side to the low concentration level side.

Further, in order to achieve the above object, the present invention has a pH adjusting means or a pH adjusting means and a hydrogen peroxide adding means, and the water to be treated containing an organic substance is treated by an accelerated oxidation reaction using ozone. A reaction vessel filled with water to be treated and fine bubble generating means for generating fine bubbles of an ozone-containing gas in the reaction vessel to dissolve ozone in the water to be treated; One or more oxidation reaction means for oxidizing organic matter in water; one or more dissolved gas removing means for degassing and removing dissolved gas in the water to be treated; and from untreated water to be treated and / or from a reaction tank. One or more TOC concentration measuring units for measuring the TOC concentration of the water to be treated from the dissolved gas removing means; and ozone for measuring the ozone concentration in the ozone-containing gas discharged onto the surface of the water to be treated in the reaction tank. concentration And tough; ozone concentration measuring unit and /
Alternatively, while controlling the measurement conditions and the output conditions in the TOC concentration measurement unit, the untreated water to be treated and the water to be treated from the reaction tank or the water to be treated from the dissolved gas removing means are controlled based on the input measurement results. And an oxidation reaction control means for controlling the circulation of the water to be treated so as to circulate the water to be mixed.

In this accelerated oxidation treatment apparatus, the oxidation reaction control means is provided in the treated water circulation channel for circulating the treated water from the reaction tank of the oxidation reaction means or the treated water from the dissolved gas removing means. It is preferable to control a treated water circulation flow rate adjustment unit that adjusts the water circulation flow rate.

In the accelerated oxidation treatment apparatus as described above, the dissolved gas removing means comprises: a retention tank having a volume capable of retaining the water to be treated whose pH has been adjusted to 5.5 or less for a predetermined time; At the top of the storage tank is connected to the pipe through which the water to be treated is fed, and the inlet of the storage tank allows the water to flow into the storage tank. A degassing gas outlet pipe, which is connected to a pipe through which the water to be treated is fed, at the lower part of the retention tank to discharge the treated water from which the dissolved gas has been degassed and removed to the outside of the retention tank. It is preferable that a tank outlet is provided. The dissolved gas removing means comprises a degassing tower for separating and degassing dissolved gas in the water to be treated whose pH has been adjusted to 5.5 or less; Is connected to the pipe through which water is supplied, and the deaeration tower inlet for flowing the water to be treated into the deaeration tower; and the water to be treated flowing from the deaeration tower inlet is formed into droplets downward to the deaeration tower. A spouting section for sprinkling water and a degassing gas outlet pipe for guiding gas degassed from the water to be treated to the outside of the degassing tower; The gas blower that blows toward the top of the gas tower, and the water to be treated that is located below the gas blower and from which the dissolved gas has been degassed and removed, is collected, and the water to be treated is sent near the bottom. A treated water collection tank having a degassing tower outlet connected to the piping that flows the treated water to the outside of the degassing tower,
May be provided.

In the present specification, the water to be treated refers to untreated water (raw water to be treated, a raw water to which a pH adjuster and / or hydrogen peroxide is added), oxidized water, etc., unless otherwise specified. The water to be treated in the treatment step of any of the reaction step or the dissolved gas removal step or the oxidant removal step or in the treatment after the treatment step, the treatment water in the circulation where the flow is switched to the circulation flow path, etc. It refers to any or all of a plurality of combinations or all of the water to be treated. In addition, the treated water is a treated water that has been subjected to at least one oxidation reaction step, the flow is not switched to the circulation flow path, and is not subjected to any of the treatment steps as an accelerated oxidation treatment. Indicates treated water.

According to the accelerated oxidation treatment method and apparatus of the present invention, the water to be treated, which is fed from the reaction tank through the oxidation reaction step, removes hydrogen carbonate ions and carbonate ions serving as scavengers in the ozone oxidation reaction. Then, a part of the water to be treated whose organic matter concentration has been reduced is treated again in the reaction tank. Since the water to be treated having a reduced organic substance concentration is mixed with the untreated water to be treated, it is sent to the reaction tank in a form diluted with the organic substance concentration in the untreated water to be treated. Therefore, the organic matter removal rate in each oxidation reaction step in the reaction tank can be set low, and the organic matter removal rate in the accelerated oxidation treatment method and the entire processing apparatus is maintained high. Further, since the organic matter removal rate in the reaction tank can be set low, the supply amount of the ozone-containing gas supplied to the reaction tank can be reduced, and the ozone utilization rate with respect to the ozone input amount is high. Furthermore, even when the concentration of organic matter in the raw water to be treated fluctuates, the conditions for the accelerated oxidation treatment are controlled according to the concentration fluctuation, so that a treatment with a high ozone utilization efficiency is always possible.

[0037]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a preferred embodiment of an accelerated oxidation treatment method and apparatus according to the present invention.

FIG. 1 is a schematic diagram showing a first embodiment of the accelerated oxidation treatment apparatus according to the present invention. The accelerated oxidation treatment apparatus according to the present embodiment includes an oxidation reaction unit 10 having a reaction tank 11 and a microbubble generating unit 12, an ozone generator 20, and a dissolved gas removing unit 40.
The reaction tank 11 is filled with the water to be treated 30. The microbubble generating means 12 is disposed near the bottom of the reaction tank 11 in the reaction tank 11 so as to be immersed in the water 30 to be treated, and is connected to the ozone generator 20 by a gas supply pipe 21. As a result, the ozone-containing gas containing ozone generated by the ozone generator 20 is supplied through the gas supply pipe 21 to the fine bubble generating means 1.
2.

In the reaction tank 11, a treated water supply pipe 3 is connected from a drainage source (not shown) to a treated water inlet 11 of the reaction tank 11.
a, a hydrogen peroxide addition unit 1 and a pH adjustment unit 2 are connected to the water supply pipe 3 at a position near the water inlet 11 a of the reaction tank 11. Also,
Hydrogen peroxide addition means 1, pH
The TOC concentration measuring unit 31 is located at a position (drainage source side) of the reaction tank 11 farther from the treated water inlet 11a than the adjusting means 2.
Is provided. A treated water feed pump (not shown) is provided at an appropriate position of the treated water supply pipe 3, for example, between the TOC concentration measuring unit 31 and the hydrogen peroxide adding means 1.

With the above configuration, the TO in the untreated water supplied from the drainage source via the treated water supply pipe 3 is determined.
The C concentration is measured by the TOC concentration measuring unit 31. Hydrogen peroxide and a pH adjuster such as sodium hydroxide and potassium hydroxide are added to the untreated water to be treated by hydrogen peroxide adding means 1 and pH adjusting means 2, and the pH of the water to be treated is increased.
H is adjusted to 7-8. The water to be treated, to which hydrogen peroxide has been added and the pH of which has been adjusted, is charged into the reaction tank 11 from the treated water inlet 11 a via the treated water supply pipe 3. The ozone-containing gas supplied from the gas supply pipe 21 is ejected as fine bubbles from the microbubble generating means 12 into the water 30 to be treated placed in the reaction tank 11 of the oxidation reaction means 10, so that Organic substances are subjected to accelerated oxidation treatment.

The reaction tank 11 has a treated water outlet 11b in addition to the treated water inlet 11a. The treated water outlet 11b is connected to the treated water supply pipe 4, and is provided at the top of the reaction tank 11 and the retention tank 41 forming the dissolved gas removing means 40 via the treated water supply pipe 4. The residence tank inlet 41a is connected. The retention tank 41 forming the dissolved gas removing means 40 is supplied with water 30 from the reaction tank 11 and flows into the retention tank 41 from the retention tank inlet 41 a.
And an acid addition section (not shown) for adding an acid to the mixture. The acid addition section adjusts the pH of the water to be treated to an acidic side of 5.5 or less.
As long as it can be adjusted, it may be provided at any position of the retention tank 41 in any form. Further, the acid addition section may be installed in the water supply pipe 4 for treated water between the treated water outlet section 11b of the reaction tank 11 and the retention tank inlet section 41a. In this case, the acid addition section may be, for example, a tank. It may be installed as a form. The retention tank 41 has a volume capable of retaining the water to be treated 30 continuously flowing from the retention tank inlet 41a for 10 minutes or more. As a result, carbonate ions including hydrogen carbonate ions in the water to be treated 30 are present as carbon dioxide (CO ₂ ), and the carbon dioxide dissolved in the water to be treated 30 is removed by being retained in the retention tank 41. I'm bothered. Further, ozone remaining dissolved in the water 30 to be treated is degassed as ozone gas together with carbon dioxide gas.

A degassing gas outlet pipe 42 is provided at the top of the storage tank 41 so as to communicate with the inside of the storage tank 41 and extend upward from the outside of the storage tank 41. Is connected to a waste gas processor (not shown) filled with. As a result, the carbon dioxide gas and ozone gas degassed from the water to be treated are led out of the retention tank 41, and the led ozone gas flows into the waste gas treatment device and is decomposed and removed by passing through the waste gas treatment device, and is decomposed and removed in the atmosphere. Will be discharged. In the lower part of the retention tank 41, near the bottom,
A stagnation tank outlet 41b is provided which communicates the inner and outer surfaces of the stagnation tank 41 and is connected to the treated water supply pipe 4.
In 1, the water to be treated 30, which has been retained for a predetermined time and from which carbonate ions have been removed, is supplied to the treated water supply pipe 4.

Retention tank 41 as dissolved gas removing means 40
From the residence tank outlet 41b to the treated water supply pipe 4
Is connected to the water supply pipe branching section 5 via the. A TOC concentration measuring unit 32 is provided in the treated water supply pipe 4 between the dissolved gas removing means 40 and the water supply pipe branching unit 5.
The to-be-processed water circulation pipe 6 and the to-be-processed water non-circulation pipe 7 are connected to the water supply pipe branch part 5. Treated water circulation pipe 6
From the water supply pipe branch section 5 to the TO
It is connected to a supply pipe branching section 8 located between the C concentration measuring section 31 and the hydrogen peroxide adding means 1.

A circulating flow rate adjusting section 33 for adjusting the circulating flow rate of the to-be-processed water 30 is provided in the to-be-processed water circulating pipe 6.
Is equipped. With the above configuration, the TOC concentration in the water to be treated 30 from which the carbonate ions have been removed by the dissolved gas removing means 40 is measured by the TOC concentration measuring unit 32, and the water to be treated 30 is passed through the treated water supply pipe 4. The water is supplied to the water supply pipe branching section 5. The to-be-processed water 30 sent to the water supply pipe branching section 5 is subjected to the to-be-processed water circulation pipe 6 and the to-be-processed water non-circulation pipe 7 according to the setting of the to-be-processed water circulation flow rate adjusting section 33.
Branched to The to-be-processed water 30 branched into the to-be-processed water circulation pipe 6 is sent to the supply pipe branch part 8, and is mixed with untreated to-be-processed water.

The TOC concentration in the to-be-treated water 30 branched into the to-be-treated water circulation pipe 6 is greatly reduced as compared with the TOC concentration in the untreated to-be-treated water.
The TOC concentration in the water to be treated 30 sent to 1 is also reduced. Therefore, the supply amount of the ozone-containing gas supplied from the gas supply pipe 21 to the microbubble generating means 12 can be set low, and the utilization efficiency of ozone is improved. The water 30 to be treated branched into the treated water circulation pipe 6 has a pH of 5.
5 or less, but after being mixed with untreated water to be treated in the supply pipe branch 8, the water to be treated is supplied to the treated water inlet 11 a of the reaction tank 11.
A pH adjuster is added by the pH adjuster 2 to adjust the pH to 7-8.
Therefore, an appropriate oxidation reaction in the oxidation reaction means 10 is possible. The non-circulation pipe 7 may be provided with an ion removing unit 50 made of, for example, a mixed bed type ion exchange resin.

An ozone concentration measuring section 22 is provided at the top of the reaction tank 11. A gas discharge pipe 23 is connected to the ozone concentration measuring section 22, and the gas discharge pipe 23 is a waste gas processor (not shown) further filled with a catalyst resin or the like.
It is connected to the. As a result, the ozone concentration in the ozone-containing gas near the top of the reaction tank 11 is measured by the ozone concentration measurement unit 22 after passing through the water 30 to be treated placed in the reaction tank 11 and discharged onto the surface of the water 30 to be treated. Is done.
The ozone-containing gas that has passed through the ozone concentration measurement unit 22 is discharged from the reaction tank 11 by the gas discharge pipe 23 and introduced into the waste gas treatment device, and the ozone in the introduced ozone-containing gas passes through the waste gas treatment device. Decomposed and removed into the atmosphere. Since the supply amount of the ozone-containing gas supplied to the oxidation reaction means 10 can be set low and the organic matter removal rate in the water to be treated 30 is set low, the ozone-containing gas is discharged onto the liquid surface of the water 30 to be treated with the ozone oxidation reaction. The ozone concentration in the ozone-containing gas is kept at a low level. Therefore, no extra load is applied to the waste gas treatment device.

Further, the accelerated oxidation treatment apparatus in the present embodiment includes an oxidation reaction control means (not shown), and the oxidation reaction control means includes a TOC concentration measuring unit 31
It has a TOC measurement control unit that controls the C concentration measurement time and the output condition of the measured value, and an ozone concentration measurement control unit that controls the ozone concentration measurement time of the ozone concentration measurement unit 22 and the output condition of the measured value. On the other hand, the TOC concentration measuring units 31 and 32 and the ozone concentration measuring unit 22 are respectively provided by the T
It has a measurement data output unit that receives a measurement control signal from the OC measurement control unit or the ozone concentration measurement control unit and outputs measurement data including a measurement time and a measurement value to the oxidation reaction control unit. The oxidation reaction control means includes a reference value recording unit that records / updates a TOC concentration reference value and an exhaust gas ozone concentration reference value that are input as a plurality of stepwise values before controlling the flow of the water to be treated. The circulation ratio of the water to be treated 30 arbitrarily set and input for each of the TOC concentration levels and each of the exhaust gas ozone concentration levels, that is, the set flow rate of the untreated water and the treated water branched to the treated water circulation pipe. A circulation ratio recording unit that records / updates the set flow rate of the water 30.

The circulating flow rate control section 33 receives the circulating flow rate control signal output from the oxidation reaction control means, and switches the circulating flow rate of the to-be-processed water 30 from 0 to a stepwise higher value. A flow control valve having a section is used. The to-be-treated water feed pump is configured to receive the circulating flow control signal output from the oxidation reaction control means, adjust the frequency of the inverter, and change the flow rate of the fed water. The oxidation reaction control means includes the TOC concentration measurement units 31 and 32
And the ozone concentration measurement unit 22 detects the TOC concentration measurement value or the ozone concentration measurement value output from the measurement data output unit, and records the TOC concentration recorded in the reference value recording unit.
A concentration level judging section for judging a TOC concentration level or an exhaust gas ozone concentration level by comparing the magnitude with a concentration reference value or an ozone concentration reference value; and a TOC concentration level or an exhaust gas ozone concentration level judged by the concentration level judging section. And a circulating flow control signal output unit that outputs a circulating flow control signal to the to-be-treated water feed pump and the to-be-treated water circulating flow adjusting unit 33 so as to circulate according to the circulating ratio of the to-be-treated water recorded in the circulating ratio recording unit. ; With such a configuration, even when the TOC concentration of the water to be treated fluctuates, the supply amount of the ozone-containing gas to the microbubble generating means 12 of the oxidation reaction means 10 can be set low according to the fluctuation. In addition, accelerated oxidation treatment can be performed under optimal ozone oxidation reaction conditions with improved ozone utilization efficiency.

In the first embodiment described above, when the pH adjusting means 2 is connected to the water supply pipe 3 without installing the hydrogen peroxide adding means 1, the water The pH of the water to be treated to be supplied to the inlet 11a is 10 to
It is adjusted to 11. The TOC concentration of the water to be treated 30 in the reaction tank 11 is determined by the oxidation of the oxidation reaction means 10 because the untreated water to be treated is diluted with the water to be treated circulated through the treated water circulation pipe 6 to reduce the TOC concentration. The supply amount of the ozone-containing gas supplied to the microbubble generating means 12 can be set low, the amount of the oxidizing agent remaining in the water to be treated 30 becomes very small, and the accelerated oxidizing treatment can be performed sufficiently without providing the oxidizing agent removing means. .

In this embodiment, the oxidation reaction means 10
A gas discharge pipe 23 is provided at the top of the
The ozone-containing gas discharged on the liquid level of 0 was discharged from the reaction tank 11 and introduced into the waste gas treatment device. However, the gas discharge pipe 23 was not provided, and the ozone-containing gas was once passed through the treated water supply pipe 4. Water may be sent to the dissolved gas removing means 40 without gas-liquid separation, and the gas may be removed from the degassing gas outlet pipe 42 of the dissolved gas removing means 40 in a lump.

Also, the oxidation reaction control means can be modified. For example, the ozone generator 20 may be changed stepwise at each TOC concentration level and at each exhaust gas ozone concentration level.
An ozone-containing gas supply set flow rate recording unit that records / updates an ozone-containing gas supply flow rate set value so that the supply amount of the ozone-containing gas supplied to the microbubble generating means 12 through the gas supply pipe 21 can be adjusted; A gas supply flow rate control signal output section for outputting a gas supply rate control signal so as to control the supply rate according to the ozone-containing gas supply flow rate recorded in the ozone-containing gas supply set flow rate recording section. good. In this case, the supply flow rate of the ozone-containing gas can be switched stepwise from 0 to 0 between the ozone generator 20 and the fine bubble generation means 12 by receiving the gas supply flow rate control signal output from the oxidation reaction control means. It is sufficient to install a gas supply flow rate adjustment unit composed of a flow rate adjustment valve configured as described above.
Thereby, accelerated oxidation treatment can be achieved with more appropriate ozone oxidation reaction conditions.

FIG. 2 is a schematic diagram showing a second embodiment of the accelerated oxidation treatment apparatus according to the present invention. Here, the same or equivalent parts as those of the first embodiment are denoted by the same reference numerals, and the detailed description is omitted. The accelerated oxidation treatment apparatus according to the present embodiment is different from the first embodiment in that the dissolved gas removing means 40 provided in the treated water supply pipe 4 is connected to the treated water circulation flow rate adjusting unit 33 of the treated water circulation pipe 6 and the supply pipe. This is an accelerated oxidation treatment device installed between the branch portion 8.
Thereby, the organic matter removal rate in the reaction tank 11 is low,
After setting the organic matter removal rate to be substantially the same as that of the first embodiment, the processing flow rate of the water to be treated 30 can be set higher. Note that the present embodiment can also be modified in the same manner as the first embodiment, such as the arrangement and form of the acid addition section and the modification of the oxidation reaction control means.

FIG. 3 is a schematic diagram showing a third embodiment of the accelerated oxidation treatment apparatus according to the present invention. In the apparatus of FIG. 3, the same or equivalent parts as those of the first embodiment are denoted by the same reference numerals, and the detailed description is omitted. In the accelerated oxidation treatment apparatus according to this embodiment, in the first embodiment, the dissolved gas removing means 40 provided in the treated water supply pipe 4 is replaced with the dissolved gas removing means 40 between the supply pipe branch portion 8 and the pH adjusting means 2. This is an example of installation in a treated water supply pipe 3. here,
Although the hydrogen peroxide addition means 1 is not provided, if the hydrogen peroxide addition means 1 is installed, the dissolved gas removal means 40
It is desirable to dispose it in the treated water supply pipe 3 between the treated water inlet portion 11a of the reaction tank 11.

Further, the dissolved gas removing means 40 in this embodiment comprises a degassing tower 45, and the top of the degassing tower 45 is connected to the degassing tower inlet 4 so as to communicate the inside and the outside of the degassing tower 45.
5 a is provided and connected to the water supply pipe 3.
The degassing tower 45 includes an acid adding section (not shown) for adding an acid to the water to be treated fed through the treated water supply pipe 3 at the degassing tower inlet 45a. Deaeration tower entrance 45a
Is installed on the top inside the degassing tower 45,
Is connected to a water sprinkling section 46 for forming the liquid to be treated, which has been fed through the hopper, into water droplets and spraying water downward. A gas blowing unit 48 such as a blower is provided below the degassing tower 45 to blow the introduced gas toward the top inside the degassing tower 45. A treated water collecting tank 49 having a height from the bottom portion of the degassing tower 45 to a position lower than the height position of the lower end of the gas blower 48 by a predetermined distance is provided. Further, at the top of the deaeration tower 45, a deaeration tower entrance 45
In addition to a, a degassing gas outlet pipe 47 is provided so as to communicate with the inside of the degassing tower 45 and to extend upward outside the degassing tower 45. The tip of the degassing gas outlet pipe 47 is connected to a waste gas processor (shown in FIG. None)
It is connected to the.

The gas introduced into the gas blowing section 48 includes
It may be air and can be sufficiently degassed. However, by using a gas having a lower CO ₂ concentration than air, the degassing efficiency can be further improved.
0, an ozone-containing gas discharged from the gas discharge pipe 23 of the reaction tank 11 can be suitably used. When the discharged ozone-containing gas is used, the end of the gas discharge pipe 23 may be connected to a gas inlet (not shown) of the gas blower 48. In addition, the pretreated raw material gas supplied to the ozone generator 20 also has a lower CO ₂ concentration than air and can be suitably used. By the dissolved gas deaeration means 40 configured as described above, the pH of the water to be treated sent through the water supply pipe 3 is adjusted to an acidity of 5.5 or less, and the water sprinkling section 46 of the degassing tower 45 is adjusted. Sprinkled from. The CO ₂ dissolved and present in the water to be treated is formed into droplets, and the gas is blown from the gas blower 48 toward the top of the degassing tower 45 while descending to the treated water collecting tank 49, thereby generating carbonic acid. Degassed as gas. The degassed carbon dioxide gas and ozone gas are supplied to a degassing gas outlet pipe 4.
The waste gas flows into the waste gas treatment device outside the degassing tower 45 through 7 and is decomposed and released into the atmosphere.

In the vicinity of the bottom of the treated water collecting tank 49, there is provided a deaeration tower outlet 45b communicating between the inside and the outside of the treated water collecting tank 49. The pipe 3 is connected, and the tip of the water supply pipe 3 is connected to the water inlet 11 a of the reaction tank 11. The pH adjusting means 2 is connected to the treated water supply pipe 3 between the deaeration tower outlet 45b and the treated water inlet 11a. As a result, the water to be treated, from which the inorganic carbonic acid has been removed and which has been collected in the treated water collecting tank 49, is discharged from the degassing tower 45 via the treated water supply pipe 3, and the pH is adjusted to 10 to 10 by the pH adjusting means 2.
After the pH is adjusted to 11, the water is sent to the reaction tank 11. Therefore, the oxidation reaction by the oxidation reaction means 10 is possible under appropriate conditions.

With such a configuration, the organic matter removal rate in the reaction tank 11 is relatively low, and can be set similarly to the first embodiment. Furthermore, when inorganic carbonic acid is contained in untreated water to be treated, it can be removed in advance before filling the reaction tank 11. Therefore, the organic matter removal rate of the entire accelerated oxidation treatment apparatus is further improved as compared with the apparatus of the first embodiment. Note that the present embodiment can also be modified in the same manner as the first embodiment, such as the arrangement and form of the acid addition section and the modification of the oxidation reaction control means.

The ozone generator 20 commonly used in the accelerated oxidation treatment apparatuses of the first to third embodiments includes a silent discharge system, an electrolysis system, a photochemical reaction system, a radiation irradiation system, a high-frequency electric field system, and the like. Although any type of apparatus can be used, a silent discharge type ozone generator having a cooler and applying an AC voltage is more preferable.

As the dissolved gas removing means 40, the first and second embodiments show an example in which the retention tank 41 is used.
This retention tank method is the simplest natural degassing, and the installation, operation, maintenance, and the like of the device are easy. On the other hand, although depending on the treatment flow rate of the water to be treated, the water to be treated is retained for a predetermined time, so that the equipment of the retention tank becomes large. In the third embodiment, an example in which the degassing tower 45 is used has been described. However, this degassing tower system has a higher degassing efficiency for dissolved gas than the residence tank system, and requires a particularly large installation area. And not. As the dissolved gas removing means 40, in addition to the above-described residence tank method and deaeration tower method, a vacuum deaeration tower method and a membrane deaeration method can be suitably used. The apparatus of the vacuum deaeration tower system includes a deaeration tower inlet part 45a and an outlet part 45b in the deaeration tower 45, a sprinkler part 46,
In addition to the same parts as the to-be-treated water collecting tank 49, etc., a vacuum device such as a vacuum pump is provided so that the inside of the degassing tower can be vacuum degassed. The operation and maintenance management is troublesome, but the degassing efficiency of dissolved gas is extremely high. The device of the membrane deaeration system is composed of a membrane deaerator having a gas-permeable and impermeable membrane, configured to be capable of gas-liquid separation of dissolved gas in the water to be treated to be sent, and the equipment becomes large. Operation and maintenance are troublesome, but the efficiency of degassing and removing dissolved gases is high. In either method,
Either an acid addition unit for adjusting the water to be treated to an acidity of pH 5.5 or less is provided, or an acid is added to a pipe for supplying and supplying the water to be treated upstream of an inlet of each device as the dissolved gas removing means 40. It is necessary that an addition section be provided.

The fine bubble generating means 12 includes an aerator type, an ejector type, a revolving type fine bubble generating type,
Any device may be used as long as it can be installed near the bottom of the reaction tank 11 and generates fine bubbles of the ozone-containing gas supplied from the ozone generator 20, such as a U-tube system. The ozone concentration measurement unit 22 is not particularly limited as long as it can measure the ozone concentration in the gas with a detection sensitivity of at least 1 g / Nm ^3. The TOC concentration measurement units 31 and 32 have at least 0.01 ppm. T that has detection sensitivity and can measure total organic carbon concentration in liquid
Any TOC meter may be used as long as it is an OC meter.

Next, the accelerated oxidation treatment method of the present invention for treating water to be treated containing an organic substance using the above-described accelerated oxidation treatment apparatus will be described.

In the accelerated oxidation treatment method using the treatment apparatus shown as the first embodiment, first, the treated water sent from the wastewater source via the treated water supply pipe 3 is treated by the hydrogen peroxide adding means 1. Hydrogen peroxide is added, and a pH adjusting agent is added by the pH adjusting means 2. The to-be-treated water whose pH has been adjusted to 7 to 8 is introduced into the reaction tank 11 from the to-be-treated water inlet 11 a of the reaction tank 11.

A microbubble generating means 12 is immersed in the water to be treated 30 in the vicinity of the bottom in the reaction tank 11, and an ozone-containing gas is supplied from the ozone generator 20 through the gas supply pipe 21 to the microbubble in the reaction tank 11. The microbubble generating means 12 is supplied to the generating means 12 and generates microbubbles of the ozone-containing gas to dissolve ozone in the water to be treated 30 so that the water to be treated 3
An oxidation reaction step of oxidizing the organic substances in O is performed. Here, the supply amount of the ozone-containing gas supplied to the microbubble generating means 12 is set low. In this oxidation reaction step, most of the oxidation reaction products are organic acids such as acetic acid and formic acid. The water to be treated 30 that has undergone the step contains carbonate ions that have been further oxidized from organic acids.

The treated water 30 having undergone the oxidation reaction step is supplied from the treated water outlet 11 b of the reaction tank 11 to the treated water supply pipe 4.
The water is supplied to the retention tank inlet 41a of the retention tank 41 that forms the dissolved gas removing means 40 through. An acid such as hydrochloric acid is added to the water to be treated 30 flowing into the stagnant tank 41 from the stagnant tank inlet 41a by the acid adding section, so that the pH is adjusted to an acidity of 5.5 or less. The pH of inorganic carbonic acid such as carbonate ions in the water to be treated is pH
When the pH is 5.5 or less, most of the water is present as CO _{2. By} keeping the water 30 adjusted to pH 5.5 or less in the retention tank 41 for a predetermined time, carbon dioxide dissolved in the water to be treated is degassed. You. The residence time of the water to be treated 30 is preferably 10 minutes or more, and the carbon dioxide gas is sufficiently degassed, and the ozone gas remaining in the water to be treated and dissolved in the water to be treated 30 is degassed (dissolved gas removal). Process). The degassed carbon dioxide gas and ozone gas are led out of the retention tank 41 through a degassing gas lead-out pipe 42 at the top of the retention tank 41. It comes into contact with the catalyst resin filled in the waste gas treatment device, is decomposed and removed, and is discharged to the atmosphere. The TOC concentration of the treated water 30 that has passed through the dissolved gas removal step is measured by a TOC concentration measuring unit 32 connected to the treated water supply pipe 4. The to-be-treated water 30 that has passed through the dissolved gas removal step contains nonionic organic substances and organic acids, but is reduced in comparison with the TOC concentration in the untreated to-be-treated water.

Subsequently, the water 30 to be treated is supplied to the water supply pipe branch 5
Thus, the water is distributed to the treated water circulation pipe 6 and the treated water non-circulation pipe 7 and sent. The treated water 30 sent to the treated water circulation pipe 6 has a flow rate of 0 through the treated water circulation flow rate control unit 33 controlled by the oxidation reaction control means.
The water is adjusted and fed stepwise, and mixed with the untreated water in the supply pipe branching section 8. When the water 30 to be circulated through at least the oxidation reaction step is mixed with the untreated water, the TOC concentration in the mixed treated water is lower than that of the untreated water. In the oxidation reaction step, carbonate ions that inhibit the oxidation reaction have been removed. Therefore, since the mixed water to be treated is sent to the reaction tank 11 again and undergoes the oxidation reaction step, the supply amount of the ozone-containing gas can be reduced.

The control of the flow of untreated water to be treated and the treated water having undergone at least the oxidation reaction step by the oxidation reaction control means is a semi-automatic control of the accelerated oxidation treatment. A plurality of TOs are stored in the reference value
Each reference value is recorded or updated by inputting the C concentration reference value and / or a plurality of exhaust gas ozone concentration reference values. Further, the input value is recorded or updated by inputting the circulation ratio of the water to be treated 30 into the circulation ratio recording unit of the oxidation reaction control means for each stepwise TOC concentration level and / or for each exhaust gas ozone concentration level.

Here, a case will be described in which the water to be treated containing an organic substance having a TOC concentration of about 30 ppm at the upper limit is controlled using an apparatus designed to perform the accelerated oxidation treatment. As the TOC concentration reference value, for example, 17 pp
m, 7 ppm, input to the reference value recording unit and recorded / updated, the TOC concentration level becomes three steps, that is, 17 p.
A high concentration level of pm or more, a medium concentration level of 7 ppm or more and less than 17 ppm, and a low concentration level of 7 ppm or less are set. Further, as the exhaust gas ozone concentration reference value, for example, 3
When 0 g / Nm ³ and 15 g / Nm ³ are set and input to the reference value recording unit and recorded / updated, the exhaust gas ozone concentration level becomes 30 g / Nm ³ or higher, 15 g / Nm ³ or higher.
Nm ³ or more 30 g / Nm ³ below the concentration level in the, 15 g
/ Nm ³ is set at three low density levels.

As the circulation ratio of the water to be treated for each TOC concentration level, for example, a high concentration level: 1.25 / 0.
25, medium density level: 1.25 / 0.5, low density level: 1.25, and input to the circulating ratio recording unit to record / update. In the case of the high concentration level, the circulation ratio of the water to be treated is set to 0.25 m ³ / hour with respect to the flow rate of the untreated water to be treated by the treated water feed pump (the treatment flow rate): 0.25 m ³ / hour. The circulation flow rate adjusted by the treated water circulation flow rate adjusting unit 33 and sent through the treated water circulation pipe 6 is 1.0 m ³ / hour and the untreated treated water supply flow rate is 0.25 m ³ / hour. The added flow rate of the treated water inlet 11a of the reaction tank 11: 1.25 m ³ /
It is time and the circulation ratio is equal to 5.

The circulation ratio for each exhaust gas ozone concentration level may be set and input in the same manner, but the reference circulation ratio is finely adjusted based on the circulation ratio input for each TOC concentration level. Is also good. For example, it is also possible to set the exhaust gas ozone concentration as follows: high concentration level: reference circulation ratio-1, medium concentration level: reference circulation ratio ± 0, low concentration level: reference circulation ratio + 1. As described above, when the type of the organic substance contained in the untreated water to be treated changes and the reactivity in the oxidation reaction step greatly changes after being set in advance, the respective set values are re-entered and each record is input. What is necessary is just to update the set value recorded in the section. By setting in this way, it is possible to more appropriately control the circulation of the water to be treated in accordance with the change in the concentration of the organic substance contained in the water to be treated.

In the above setting, two TOC concentration reference values and two exhaust gas ozone concentration reference values are set. However, the number of reference values is increased, for example, four are set, and each is set as five concentration levels. You may. Thereby, it is possible to respond to a more appropriate change in the concentration of the organic substance. Here, the supply flow rate of the ozone-containing gas supplied to the microbubble generating means 12 and the ozone-containing gas discharged onto the surface of the water to be treated 30 are converted into the ozone-containing gas from the ozone generator 20. Although an example in which the control of the mixing ratio to be mixed is not performed is described, when performing these controls in combination, the reference value, the gas supply flow rate set value for each concentration level, the mixing ratio, and the like are set in advance. Are required, and may be set in the same manner as in the case of the flow of the water to be treated. In such a case, as the TOC concentration level determined by the concentration level determination unit of the oxidation reaction control means moves from the high concentration level side to the low concentration level side, the reaction tank of the ozone-containing gas from the ozone gas generator 20. It is preferable to set the supply flow rate to 11 so as to decrease. Also, as the exhaust gas ozone concentration level determined by the concentration level determination section of the oxidation reaction control means goes from the high concentration level side to the low concentration level side, the ozone gas generator 20 supplies the ozone-containing gas to the reaction tank 11. Preferably, the flow rate is set to increase. This enables a more advanced control of the accelerated oxidation reaction.

The TOC measurement control section and the ozone concentration measurement control section of the oxidation reaction control means send measurement control signals to the respective measurement data output sections of the TOC concentration measurement sections 31 and 32 and the ozone concentration measurement section 22 at predetermined time intervals. Output. The measurement data output units of the TOC concentration measurement units 31 and 32 and the ozone concentration measurement unit 22 receive the measurement control signal and output measurement data including the measurement time and the measurement result to the oxidation reaction control unit. The concentration level determination unit of the oxidation reaction control unit detects the TOC concentration measurement data output from the measurement data output units of the TOC concentration measurement units 31 and 32, and detects each TOC concentration measurement value included in each TOC concentration measurement data. Is compared with a plurality of TOC concentration reference values recorded in a reference value recording section of the oxidation reaction control means, and the TOC concentration level of untreated water and / or at least water to be treated which has undergone an oxidation reaction step is compared. (TOC concentration level determination step).

The concentration level judgment section of the oxidation reaction control means detects the ozone concentration measurement data output from the measurement data output section of the ozone concentration measurement section 22 and detects the ozone concentration measurement value included in the ozone concentration measurement data. Is compared with a plurality of exhaust gas ozone concentration reference values recorded in a reference value recording unit of the oxidation reaction control means, and the ozone-containing gas discharged into the reaction tank 11 and on the liquid surface of the water to be treated 30 is compared. Is determined (exhaust gas ozone concentration level determining step).

Subsequently, the oxidation reaction control means is recorded in the circulation ratio recording section according to the TOC concentration level and / or the exhaust gas ozone concentration level determined in the TOC concentration level determination step and / or the exhaust gas ozone concentration level determination step. A circulating flow control signal for changing the circulating flow rate based on the circulating water ratio for each of the TOC concentration levels and / or the exhaust gas ozone concentration levels is output from the circulating flow rate control signal output section to the effluent water supply pump. It outputs to the to-be-processed water circulation flow rate adjustment part 33. In response to the circulating flow control signal,
The to-be-processed water feed pump changes the water supply flow rate by adjusting the frequency of the inverter so as to match the flow rate change value of the untreated to-be-processed water included in the circulation flow rate control signal. In addition, in response to the circulating flow control signal, the to-be-processed water circulating flow rate adjusting unit 33 changes the circulating flow rate in which the to-be-processed water that has been passed through at least the oxidation reaction step contained in the circulating flow control signal is fed through the to-be-processed water circulating pipe 6. To match the value,
The water supply flow rate is changed by activating the valve drive unit of the to-be-processed water circulation flow rate control unit 33 and switching the flow rate control valve.

By controlling the accelerated oxidation treatment apparatus as described above, even in the case where the type and concentration of organic matter in the water to be treated from the wastewater source fluctuate, an efficient reaction according to the situation in the oxidation reaction step is always performed. Ozone can be used, and an accelerated oxidation treatment with a minimum amount of ozone used can be realized. In addition,
A modified device other than the device of the first embodiment and second,
Regarding the accelerated oxidation treatment method in the case of using the device of the third embodiment, the treatment operation including the circulation control of the water to be treated is performed according to the configuration of each device. The same effect as when used is obtained. A detailed description of the accelerated oxidation treatment method using these devices is omitted, but the main differences are as follows.

When the apparatus according to the second embodiment is used, in the dissolved gas removing step, the water to be treated 30
Among them, inorganic carbonic acid such as carbonate ions in the water to be treated 30 distributed and circulated to the water to be treated circulation 6 in the water supply pipe branching section 5 is degassed and removed by the dissolved gas removing means 40 as carbon dioxide gas. In this case, the circulation flow rate of the water to be treated can be set higher, and the treatment can be completed within a shorter time.

In the case of using the apparatus of the third embodiment, in the dissolved gas removing step, before the oxidation reaction step, the untreated water to be treated and the inner water supply of the water to be treated 30 having undergone at least the oxidation reaction step. The purpose of the present invention is to remove the inorganic carbonic acid such as carbonate ions in the water to be treated mixed with the water to be treated 30 circulated and circulated to the water to be treated circulation 6 at the pipe branching section 5 by means of the dissolved gas removing means 40. Thereby, in the case where the untreated water to be treated contains inorganic carbonic acid, it can be removed in advance before the oxidation reaction step, and the organic matter removal rate as a whole of the accelerated oxidation treatment method is the same as that of the apparatus of the first embodiment. It is even better than in the case of.

As the dissolved gas removing means 40 in the apparatus of the third embodiment, a degassing tower system is adopted unlike the residence tank system of the first and second embodiments. The dissolved gas removing step in the case of the apparatus according to the third embodiment is as follows. That is, the untreated water or the untreated water mixed with the untreated water and the treated water circulated through the treated water circulation pipe in the supply pipe branch section 8 is supplied to the treated water supply. Water is fed from the degassing tower inlet 45a through the pipe 3, and an acid such as hydrochloric acid is added by an acid adding section to adjust the pH to 5.5 or less.
Flows into. By adjusting the pH to 5.5 or less, the inorganic carbonic acid in the water to be treated is present as CO ₂ . The water to be treated that has flowed into the degassing tower 45 is formed into droplets and sprinkled by a sprinkling unit 46 provided at the top of the degassing tower 45, and descends in the degassing tower 45. Air or an ozone-containing gas discharged from the gas discharge pipe 23 of the reaction tank 11 is supplied from a gas blower 48 provided at a lower portion of the degassing tower 45.
5 It is blown toward the top. As a result, CO ₂ dissolved in the water to be treated, which is formed into droplets and descends in the degassing tower 45, is degassed as carbon dioxide gas. At the same time, ozone remaining and dissolved in the water to be treated is degassed. The water degassed in this manner is supplied to the water collecting tank 49.
Descends and is collected. Retention tank 4 of the first and second embodiments
1, the degassing tower system using the degassing tower 45 has a higher degassing efficiency, and inorganic carbon dioxide in the water to be collected collected in the water collecting tank 49 is more highly removed. Have been.

In the dissolved gas removing step in the apparatus provided with the dissolved gas removing means 40 of the vacuum degassing tower type, an acid such as hydrochloric acid is added by an acid adding section to adjust the pH to 5.5 or less and then flow into the vacuum degassing tower. The part where the water to be treated is converted into droplets by the water spraying part provided at the top of the vacuum degassing tower and descends in the vacuum degassing tower is the same as the case using the device using the degassing tower 45. Here, the inside of the vacuum degassing tower is evacuated by a vacuum pump connected to the top, and the process part in which CO ₂ dissolved in the water to be treated that is dropped and falls is degassed as carbon dioxide is different. . The degassing efficiency by such a vacuum degassing tower method is higher than that of the degassing tower method, and a high degree of removal of inorganic carbonic acid in the dissolved gas removing step is possible. Further, in the dissolved gas removing step in the apparatus including the membrane deaerator, the water to be treated, which is adjusted to a pH of 5.5 or less by adding an acid such as hydrochloric acid by the acid addition unit, is sent to the membrane deaerator. The supplied water to be treated is separated into gas and liquid by a gas-permeable and non-permeable membrane inside the membrane deaerator, whereby CO _{2 in the} water to be treated is degassed as carbon dioxide. Deaeration by such a membrane deaeration method depends on the water supply conditions of the water to be treated and the deaeration performance of the membrane used,
High degassing efficiency can be obtained, and inorganic carbonic acid in the water to be treated can be highly removed in the dissolved gas removing step.

Hereinafter, the accelerated oxidation treatment method and apparatus of the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0080]

[Examples 1 to 3] Example 1 is the accelerated oxidation treatment apparatus of the first embodiment shown in FIG. 1, and Example 2 is the apparatus of the second embodiment shown in FIG. In Example 3, FIG.
In the apparatus according to the third embodiment shown in FIG. 1, the apparatus provided with an additional hydrogen peroxide addition means 1 in the treated water supply pipe 3 between the dissolved gas removal means 40 and the pH adjustment means 2 was used, and the following conditions were used. IPA of about 20 ppm as TOC concentration
To be treated was treated. The dissolved gas removing means 40 provided in the apparatus of the third embodiment is of the same retention tank type as the apparatus of the first embodiment, and the fine bubble generating means 12 is of a rotary blade aerator type.

The treatment flow rate (treatment water feed pump flow rate) was fixed at 0.25 m ³ / hour, the circulation flow rate was fixed at 1.0 m ³ / hour (circulation ratio: 5), and the ozone concentration was about 120 g / Nm ³ . The gas was supplied at a supply flow rate of 0.35 m ³ / hour. The concentration of hydrogen peroxide added was 20 ppm, sodium hydroxide was used as a pH adjuster, and the pH at the inlet of the reactor was 7
Adjusted to ~ 8.

Table 2 shows the treatment results when the treated water was treated to a concentration of about 4 ppm according to Examples 1 to 3.

[Table 2]

Table 2 shows the amount of ozone required when the raw water having a TOC concentration of about 20 ppm is treated to a TOC concentration of about 4 ppm, by ΔO ₃ / ΔTOC (g / g).
Are shown as ozone input and consumption, respectively. The results correspond to the results shown in Table 1 as Test Example 2 by an apparatus / method for performing accelerated oxidation treatment without circulating the water to be treated. As is clear from Tables 1 and 2, the ozone input amount was 10.2 to 10.3 compared to 14.8 in Test Example 2.
6, which indicates that in all of Examples 1 to 3, it can be suppressed to about 70%. The ozone consumption was about 70% of the case where the treatment was performed up to the TOC concentration of 3.9 ppm in Test Example 2, and the TOC concentration was 1 in Test Example 2.
20% below the consumption level when treated to 3.6 ppm
Although moderately high, a TOC concentration of about 4 ppm is achieved at this level of consumption. Here, the dissolved gas removing means 4
In the case where the water to be treated is circulated without the removal of carbon dioxide by the method of Example 0, the ozone consumption per unit TOC concentration is somewhat reduced as compared with the case of Test Example 2. Since carbonate ions that inhibit the accelerated oxidation reaction of ionic organic substances are accumulated, it is clear that the remarkable effects as in Examples 1 to 3 cannot be expected, and the test was not performed.

Example 4 Using the accelerated oxidation treatment apparatus of the first embodiment shown in FIG. 1, the TOC concentration of the raw water to be treated (untreated water) was changed to include the control of the circulation ratio. Under the following conditions. Prior to the start of the treatment, the TOC concentration reference values preset and input to the oxidation reaction control means were 17 ppm and 7 ppm, and were set at three levels of concentration. The circulation ratio setting for each TOC concentration level is
High density level: 1.25 / 0.25, medium density level:
1.25 / 0.5, low concentration level: 1.25 / 1.25
Entered as The exhaust gas ozone concentration reference value was not set and the input to the oxidation reaction control means was not performed. In addition,
The microbubble generating means 12 provided in the accelerated oxidation treatment apparatus is of a rotary blade aerator type.

Raw water to be treated having three different IPA contents is sequentially fed to the treated water supply pipe 3, and an ozone-containing gas having an ozone concentration of about 120 g / Nm ³ is supplied at a supply flow rate of 0.35 m ³ / hour. Supplied fixed. The concentration of hydrogen peroxide added was 20 ppm, and the pH at the inlet of the reaction tank was adjusted to 7 to 8 using sodium hydroxide as a pH adjuster.

[Comparative Example 1] With the fixed initial setting conditions corresponding to the high-concentration level circulation control conditions in the fourth embodiment, the recording of the TOC concentration reference value in the oxidation reaction control means is canceled and the circulation ratio is reduced. Without performing the control, the raw water to be treated containing the IPA having a TOC concentration of about 4 ppm was supplied to the treated water supply pipe 3 to perform the treatment. Other processing conditions were the same as in Example 4.

Comparative Example 2 Using the apparatus of the first embodiment shown in FIG. 1, without controlling the circulation of the water to be treated by the oxidation reaction control means, a TOC concentration of about 20 ppm was obtained.
The raw water to be treated containing PA was supplied to the treated water supply pipe 3 for treatment. Other processing conditions were the same as in Example 4.

Table 3 shows the processing results of Example 4 and Comparative Examples 1 and 2.

[Table 3]

As is clear from Table 3, in the fourth embodiment, the exhaust gas ozone concentration is controlled to 18 to 18 regardless of the TOC concentration of the raw water to be treated by controlling the circulation ratio of the water to be treated.
It is kept at 22 g / Nm ³ and the treated water has a TOC concentration of 4 ppm or less. On the other hand, in Comparative Example 1, the TOC concentration of the treated water was 2 ppm or less, but the exhaust gas ozone concentration was 59 g / Nm ³ , and about 50% of the ozone supply amount was discharged without being consumed. Comparative Example 2
Although the exhaust gas ozone concentration is as low as 1 g / Nm ³ , the ozone consumption per unit TOC concentration is increased by 40% as compared with the high concentration control example of Example 4, and the TOC concentration of the treated water is about 4 ppm. Was not achieved and remained at 6.8 ppm.

[0090]

As described above, according to the accelerated oxidation treatment method and apparatus of the present invention, the amount of ozone used is minimized, and high organic substances can be obtained without using an ion removing apparatus by ion exchange. A removal rate is obtained. In addition, even when the organic matter content in the raw water to be treated fluctuates,
Processing with high ozone utilization efficiency is always possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a first embodiment of a promoted oxidation treatment apparatus according to the present invention.

FIG. 2 is a configuration diagram schematically showing a second embodiment of the accelerated oxidation treatment apparatus according to the present invention.

FIG. 3 is a configuration diagram schematically showing a third embodiment of the accelerated oxidation treatment apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydrogen peroxide addition means 2 pH adjustment means 3 Treated water supply pipe 4 Treated water supply pipe 5 Water supply pipe branch 6 Treated water circulation pipe 7 Treated water non-circulation pipe 8 Supply pipe branch 10 Oxidation reaction means 11 Reaction Vessel 11a Treated water inlet 11b Treated water outlet 12 Fine bubble generating means 20 Ozone generator 21 Gas supply pipe 22 Ozone concentration measuring section 23 Gas exhaust pipe 30 Treated water 31, 32 TOC concentration measuring section 33 Treated water circulation Flow rate adjusting unit 40 Dissolved gas removing means 41 Reservoir 41a Reservoir inlet 41b Reservoir outlet 42, 47 Degassing gas outlet pipe 45 Degassing tower 45a Degassing tower inlet 45b Degassing tower outlet 46 Sprinkler 48 Gas Blower 49 Treated water collection tank

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D037 AA13 AB11 BA23 BB05 CA11 CA12 CA14 CA15 4D050 AA13 AB11 BB02 BB09 BC10 BD03 BD06 BD08 CA03 CA08 CA13

Claims (15)

[Claims] 1. A method for promoting oxidation treatment, comprising adding a pH adjuster or a pH adjuster and hydrogen peroxide to water to be treated containing an organic substance and treating the water to be treated by an accelerated oxidation reaction using ozone. An ozone-containing gas is supplied to a reaction tank filled with treated water, and one or more oxidation reactions for oxidizing organic substances in the treated water by generating fine bubbles of the supplied ozone-containing gas and dissolving ozone in the treated water. And at least one dissolved gas removal step of removing inorganic carbonic acid in the water to be treated as carbon dioxide gas by degassing the water to be treated, wherein the untreated water to be treated and / or at least an oxidation reaction The TOC concentration of the water to be treated that has passed through the process and / or the ozone concentration of the ozone-containing gas discharged onto the surface of the water to be treated in the reaction tank is measured. Promoting oxidation method characterized by controlling the flow of the water to be treated via at least the oxidation reaction step with physical water. 2. The method according to claim 1, wherein the step of removing the dissolved gas has a pH of 5.5.
The accelerated oxidation treatment method according to claim 1, wherein the water to be treated adjusted as described below is retained in a retention tank for a predetermined time and degassed to remove inorganic carbonic acid in the water to be treated as carbon dioxide gas. 3. The method according to claim 1, wherein the step of removing the dissolved gas comprises adjusting the pH to 5.5.
It is characterized by removing the inorganic carbonic acid in the water to be treated as carbon dioxide by subjecting the water to be treated adjusted below to droplets from the top and dropping the water and sending it to a degassing tower that blows from the bottom and degassed. The accelerated oxidation treatment method according to claim 1. 4. The method according to claim 1, wherein the step of removing dissolved gas has a pH of 5.5.
Inorganic carbonic acid in the water to be treated is removed as carbon dioxide by sending it to a vacuum degassing tower where the water to be treated adjusted below is converted to droplets from the top and lowered, and the inside of the tower is vacuum degassed from the top and degassed. The accelerated oxidation treatment method according to claim 1, wherein: 5. The method according to claim 1, wherein the step of removing the dissolved gas has a pH of 5.5.
Removal of the inorganic carbonic acid in the water to be treated as carbon dioxide by feeding the water to be treated adjusted as follows to a membrane deaerator for gas-liquid separation by a gas-permeable and impermeable membrane and degassing the water. The accelerated oxidation treatment method according to claim 1, wherein: 6. The method according to claim 1, wherein the dissolved gas removing step removes, as a carbon dioxide gas, inorganic carbonic acid in the water to be treated that has undergone at least the oxidation reaction step at a stage subsequent to the oxidation reaction step. 3. The accelerated oxidation treatment method described in 1. above. 7. The dissolved gas removal step removes, as carbon dioxide gas, inorganic carbonic acid in the water to be treated circulating so as to be mixed with the untreated water to be treated, at least among the water to be treated after the oxidation reaction step. The accelerated oxidation treatment method according to any one of claims 1 to 5, wherein: 8. The dissolved gas removal step is a step prior to the oxidation reaction step, in which the untreated water or the untreated water mixed with the at least water subjected to the oxidation reaction step is treated water. The accelerated oxidation treatment method according to any one of claims 1 to 5, wherein the inorganic carbonic acid is removed as carbon dioxide. 9. The control of the flow of the water to be treated is performed by measuring the measured TOC concentration of the untreated water to be treated and / or at least the TOC concentration of the water to be treated that has undergone at least an oxidation reaction step, and TOC for determining the TOC concentration level of untreated water to be treated and / or at least water to be treated that has undergone an oxidation reaction step by comparing the magnitude with the TOC concentration reference value
The exhaust gas ozone concentration level is determined by comparing the measured ozone concentration value in the exhausted ozone-containing gas and / or a plurality of arbitrarily preset exhaust gas ozone concentration reference values in a concentration level determination step. An exhaust gas ozone concentration level judging step, wherein the water to be treated that has passed through at least the oxidation reaction step with respect to the flow rate of the untreated water to be treated, which is arbitrarily set in advance according to the TOC concentration level and / or the exhaust gas ozone concentration level, The accelerated oxidation treatment according to any one of claims 1 to 8, wherein the circulation of the water to be treated is controlled based on a circulation ratio that is a ratio of a circulation flow rate circulating so as to be mixed with the water to be treated. Method. 10. The circulation ratio is set to decrease as the TOC concentration level determined in the TOC concentration level determination step goes from the high concentration level side to the low concentration level side. Item 10. The accelerated oxidation treatment method according to Item 9. 11. The recirculation ratio is set to increase as the exhaust gas ozone concentration level determined in the exhaust gas ozone concentration level determination step goes from a high concentration level side to a low concentration level side. Claim 9
Or the accelerated oxidation treatment method according to 10. 12. An accelerated oxidation treatment apparatus comprising a pH adjusting means or a pH adjusting means and a hydrogen peroxide adding means, wherein treated water containing an organic substance is treated by an accelerated oxidation reaction using ozone. And a microbubble generating means for generating microbubbles of an ozone-containing gas in the reactor to dissolve ozone in the water to be treated, and oxidizing one or more organic substances in the water to be treated. Reaction means, one or more dissolved gas removing means for degassing and removing dissolved gas in the water to be treated, and removing from the untreated water to be treated and / or the reaction tank or from the dissolved gas removing means. One or more TOC concentration measuring units for measuring the TOC concentration of the treated water; an ozone concentration measuring unit for measuring the ozone concentration of the ozone-containing gas discharged onto the surface of the water to be treated in the reaction tank; Controlling measurement conditions and output conditions in the zone concentration measurement unit and / or the TOC concentration measurement unit, and removing the untreated water and the treated water or dissolved gas from the reaction tank based on the input measurement results. An oxidation reaction control means for controlling the circulation of the water to be treated so that the water to be treated is mixed with the water to be treated from the means. 13. The treatment water circulation passage for circulating the treatment water from the reaction tank of the oxidation reaction device or the treatment water from the dissolved gas removing unit, wherein the oxidation reaction control means is provided in the treatment water circulation channel. 13. The circulating flow rate control section for controlling the circulating flow rate of the treated water is controlled.
2. The accelerated oxidation treatment apparatus according to 1. 14. The dissolved gas removing means comprises a retention tank having a volume capable of retaining the water to be treated, the pH of which has been adjusted to 5.5 or less, for a predetermined time. A stagnant tank inlet portion connected to a pipe through which water is supplied and allowing the water to be treated to flow into the stagnant tank, and a degassing gas outlet pipe for guiding gas degassed from the stagnated water to be treated to the outside of the stagnating tank, In the lower part of the retention tank, a retention tank outlet portion is provided, which is connected to a pipe through which the water to be treated is supplied, and which discharges the treated water from which the dissolved gas has been degassed and removed to the outside of the retention tank. The accelerated oxidation treatment apparatus according to claim 12 or 13, wherein: 15. The degassing means comprises a degassing tower for gas-liquid separation and degassing of a dissolved gas in the water to be treated whose pH has been adjusted to 5.5 or less. Is a degassing tower inlet connected to a pipe through which the water to be treated is fed, and allows the water to flow into the degassing tower; A water sprinkling section for forming a droplet toward the water sprinkler, and a degassing gas outlet pipe for guiding gas degassed from the water to be treated to the outside of the degassing tower are provided. A gas blower that blows the introduced gas toward the top of the degassing tower, and a water-collecting treatment water that is located below the gas blower and from which the dissolved gas has been degassed and removed. A treated water collection tank having a degassing tower outlet that is connected to a pipe through which the treated water is fed and flows the treated water outside the degassing tower, Promote oxidation processing apparatus according to claim 12 or 13, characterized in that provided.