KR101585143B1 - Method and apparatus for treating 1,4-dioxane in waste water - Google Patents

Abstract

Treatment of 1,4-dioxane in wastewater that can effectively reduce the release of 1,4-dioxane into the atmosphere when treating wastewater containing 1,4-dioxane by accelerated oxidation using ozone gas Method and apparatus therefor.
The method of treating 1,4-dioxane in the wastewater of the present invention occurs in an accelerated oxidation process for decomposing 1,4-dioxane contained in wastewater by using at least one of ozone treatment, hydrogen peroxide treatment and ultraviolet ray treatment together And the 1,4-dioxane-containing waste gas calculated together with the ozone gas is dissolved in water to make the 1,4-dioxane aqueous solution.

Description

METHOD AND APPARATUS FOR TREATING 1,4-DIOXANE IN WASTE WATER FIELD OF THE INVENTION [0001]

The present invention relates to a method for treating 1,4-dioxane in wastewater containing 1,4-dioxane, in which 1,4-dioxane in wastewater is treated by an accelerated oxidation method (AOP method) ≪ / RTI >

1,4-dioxane is generally used as a solvent or the like, and is often used in particular as a solvent for paints and the like. It is also contained in detergents such as commercially available polyoxyalkyl ethers. For this reason, it is possible to produce 1,4-dioxane through factory wastewater from a manufacturing plant for producing 1,4-dioxane or a polyoxyalkyl ether, and domestic wastewater using polyoxyalkyl ether- Is discharged through sewage or the like.

However, since 1,4-dioxane is a water-soluble refractory substance, it can hardly be decomposed by biological treatment or solid-liquid separation treatment in a sewage treatment plant, and there is concern about contamination of the water environment .

On the other hand, 1,4-dioxane is detected in a wide range in the environmental pollution survey of the designated chemical substance performed by the EPA, and contamination particularly in a water environment such as a river or a lake has been reported. It is also reported that a high concentration of dioxane is detected from groundwater.

From this background, with the revision of the water supply law of April 16, 2004, the content of 1,4-dioxane as a drinking water standard was regulated to 0.05 mg / L. In addition, environmental standard values were established in November 22, 2010, and a treatment technique for efficiently decomposing and removing 1,4-dioxane in wastewater is desired.

Conventionally, as a method for decomposing 1,4-dioxane in wastewater, there has been proposed a promoted oxidation method for promoting the formation of OH radicals, for example, by mainly using ozone treatment and using hydrogen peroxide treatment and ultraviolet ray treatment For example, Patent Documents 1 to 3).

Japanese Patent Application Laid-Open No. 2001-29966 Japanese Patent Laid-Open No. 2001-121163 Japanese Patent Laid-Open No. 2000-202466

However, in the ozone treatment of the accelerated oxidation method, since ozone gas is diffused from the bottom of the treatment tank and supplied into the tank, a part of the 1,4-dioxane in the wastewater flows into the gas containing ozone gas Air bubbles) from the liquid to the gas.

7 is a graph showing the effect of removing 1,4-dioxane by weak aeration. The graph is obtained by measuring the concentration of 1,4-dioxane when a 12 L reactor was aeration at 2 l / min. The abscissa in the figure represents the aeration time (Hr), and the ordinate represents the 1,4-dioxane concentration (mg / L). In addition, Fig. 7 shows only the aeration treatment and no decomposition treatment of 1,4-dioxane. As shown in the figure, the 1,4-dioxane (235 mg / L) before the start of the aeration treatment is reduced to about 180 mg / L by the aeration treatment for about 140 hours. By aerobic treatment, 1,4-dioxane in the aqueous solution is formed and released into the atmosphere. 1,4-dioxane is a substance harmful to human body, and emission into the atmosphere needs to be reduced as much as possible.

In the accelerated oxidation method, not all of the ozone gas can be used, but ozone gas of about 3 to 20% of the amount of the implantation is discharged as the exhaust gas, depending on conditions such as the depth of water. The ozone gas is harmful to the human body, and it is necessary to decompose and remove the ozone gas, and it is usually decomposed into oxygen by a catalyst such as activated carbon. This catalyst needs to be replaced periodically, and it is preferable that the exhaust gas treatment is not costly.

DISCLOSURE OF THE INVENTION Accordingly, the present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a process for the production of 1,4-dioxane, which releases 1,4-dioxane into the atmosphere when treating wastewater containing 1,4-dioxane by accelerated oxidation using ozone gas And a method for treating 1,4-dioxane in wastewater that can be efficiently reduced.

The method of treating 1,4-dioxane in the wastewater of the present invention occurs in an accelerated oxidation process for decomposing 1,4-dioxane contained in wastewater by using at least one of ozone treatment, hydrogen peroxide treatment and ultraviolet ray treatment together And the 1,4-dioxane-containing waste gas calculated together with the ozone gas is dissolved in water to make the 1,4-dioxane aqueous solution.

Thereby, it is possible to efficiently recover 1,4-dioxane contained in the waste gas discharged from the accelerated oxidation process using ozone gas, and there is no possibility of release to the atmosphere.

The aqueous solution is sprayed to the flow path of the waste gas in the casing by a scrubber equipped with a sprayer of the water in the casing to bring the waste gas and the water into gas-liquid contact.

Thereby, 1,4-dioxane calculated together with the ozone gas can be efficiently made into an aqueous solution, and there is no fear of corrosion of the pipe due to ozone gas.

The water to be supplied to the scrubber is characterized in that treated water treated in the accelerated oxidation process is used.

Thereby, it is not necessary to newly supply water for dissolving 1,4-dioxane from the outside, so that the total amount of treated water is not increased, and the cost of the whole decomposition treatment can be reduced.

Wherein the aqueous solution is obtained by dissolving the 1,4-dioxane in the treated water of the biological treatment process using the waste gas as an acid gas for an acid treatment in a biological treatment process in a different line from the treatment line including the accelerated oxidation process .

Thereby, it is not necessary to newly install an apparatus such as a scrubber in order to make 1,4-dioxane aqueous solution. Therefore, the overall cost of the apparatus can be reduced.

The aqueous solution is characterized in that the 1,4-dioxane is dissolved in the treated water of the biological treatment process by using the waste gas as an acid gas in the biological treatment process in the preceding stage of the facilitated oxidation process .

Thereby, it is not necessary to newly install an apparatus such as a scrubber in order to make 1,4-dioxane aqueous solution. By using a biological treatment tank on the same line as the accelerated oxidation process, it is possible to reduce the cost of the entire apparatus.

Wherein the biological treatment step is performed in a plurality of biological treatment tanks arranged in series in the preceding stage of the facilitated oxidation step.

This makes it possible to set the ozone concentration of the biological treatment tank on the downstream side to be lower than the ozone concentration of the upstream biological treatment tank, and to form a biological treatment environment suitable for biological treatment.

And the 1,4-dioxane discharged from the scrubber is introduced into the biological treatment process at the upstream end of the accelerated oxidation process.

Thereby, there is no fear that the ozone will corrode the pipe while the ozone gas is introduced into the biological treatment tank. Therefore, it is possible to reduce the amount of 1,4-dioxane discharged out of the system, and to prevent aging deterioration of the entire apparatus.

The apparatus for treating 1,4-dioxane in wastewater according to the present invention is a device for decomposing 1,4-dioxane contained in wastewater using at least one of ultraviolet rays, hydrogen peroxide water, and an alkaline solution and ozone gas An oxidizing means for oxidizing the 1,4-dioxane to bring the waste gas containing the 1,4-dioxane arised together with the ozone gas generated in the accelerated oxidation process of the promoting oxidation means into contact with water, And the like.

Thereby, the 1,4-dioxane contained in the exhaust gas discharged in the accelerated oxidation process can be efficiently recovered, and there is no possibility of release to the atmosphere.

The aqueous solution of 1,4-dioxane is a scrubber which has an atomizer for water in the casing and sprays the waste gas through the atomizer in the flow path of the waste gas in the casing to vapor-liquid contact the waste gas and the water. .

Thereby, 1,4-dioxane calculated together with the ozone gas can be efficiently made into an aqueous solution, and there is no fear of corrosion of piping due to ozone gas.

Characterized in that the water to be supplied to the scrubber is treated water treated by the accelerated oxidation means.

Thereby, it is not necessary to newly supply water for dissolving 1,4-dioxane from outside, so that the total amount of treated water is not increased, and the cost of the entire treatment can be reduced.

The aqueous solution of 1,4-dioxane is characterized by being a biological treatment means using the waste gas as an acid gas for a biological treatment tank in a different line from the treatment line including the accelerated oxidation means.

Thereby, it is not necessary to newly install an apparatus such as a scrubber in order to make 1,4-dioxane aqueous solution. Therefore, the overall cost of the apparatus can be reduced.

The aqueous solution of 1,4-dioxane is characterized by being a biological treatment means using the waste gas as an acid gas for the biological treatment tank at the upstream of the accelerated oxidation means.

Thereby, it is not necessary to newly install an apparatus such as a scrubber in order to make 1,4-dioxane aqueous solution. By using a biological treatment tank on the same line as the accelerated oxidation process, the cost of the apparatus can be reduced.

Characterized in that the biological treatment means is performed in a plurality of biological treatment tanks arranged in series in front of the accelerated oxidation means.

This makes it possible to set the ozone concentration of the biological treatment tank on the downstream side to be lower than the ozone concentration of the upstream biological treatment tank, and to form a biological treatment environment suitable for biological treatment.

And the 1,4-dioxane discharged from the scrubber is introduced into the biological treatment means at the upstream side of the accelerated oxidation means.

Thereby, there is no fear that the ozone will corrode the pipe while the ozone gas is introduced into the biological treatment tank. Therefore, it is possible to reduce the amount of 1,4-dioxane discharged out of the system, and to prevent aged deterioration of the entire apparatus.

According to the method and apparatus for treating 1,4-dioxane in the wastewater of the present invention having the above structure, 1,4-dioxane contained in the exhaust gas discharged in the accelerated oxidation process can be recovered easily and efficiently , There is no danger of being released into the atmosphere.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the first embodiment; FIG.
2 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the second embodiment.
3 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the third embodiment.
4 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the fourth embodiment.
5 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the fifth embodiment.
6 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the sixth embodiment.
7 is a graph showing the effect of removing 1,4-dioxane by weak aeration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of treating 1,4-dioxane in waste water of the present invention and embodiments of the apparatus will be described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the first embodiment; FIG. As shown in the figure, the apparatus 10 for treating 1,4-dioxane in wastewater according to the first embodiment (hereinafter, simply referred to as a treatment apparatus 10) is a device for treating at least one of ozone treatment, hydrogen peroxide treatment, (20) which is an accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater into OH radicals in combination with the ozone gas generated in the accelerated oxidation process of the promoted oxidation means And a scrubber device 50 as a means for aqueous solution of 1,4-dioxane for contacting waste gas containing 1,4-dioxane with water.

A storage tank 12 is disposed at the front end of the promotional oxidation apparatus 20 of the processing apparatus 10. [ The storage tank 12 temporarily stores the raw water flowing from the upstream side while considering the fluctuation of the raw water flow rate. The raw water that has been stored is passed through the introduction pipe 22 by the pump 14 of the introduction pipe 22 disposed between the storage tank 12 and the facilitation oxidation processing device 20, And sent to the oxidation processing apparatus 20.

In the facilitated oxidation treatment apparatus 20, a raw water introduction pipe 22 is connected to the bottom surface of the treatment tank, and a treatment water lead-out pipe 24 is connected to the side surface of the treatment tank. An ozone treatment device 30 and an ultraviolet irradiating device 40 are provided in the accelerated oxidation treatment device 20.

The ozone treatment device 30 is composed of an ozone generator 32, an ozone gas injection pipe 34 and an air diffuser 36. The ozone generator 32 is mounted in the vicinity of the promotional oxidation apparatus 20 and generates ozone gas. The generated ozone gas passes through the ozone gas injection pipe 34 and is diffused into the wastewater by the air diffuser 36 disposed at the bottom of the promotional oxidation apparatus 20. The ozone gas generated in the wastewater is exhausted from the exhaust pipe 26 provided in the upper part of the promotional oxidation apparatus 20. As an example, it is preferable that the amount of ozone gas of about 10 mg / L to 300 mg / L is injected from the ozone treatment device 30 in the accelerated oxidation treatment device 20.

The ultraviolet ray irradiating device 40 is installed upright at the center of the promotional oxidation processing device 20 and ultraviolet rays of a predetermined wavelength are irradiated to wastewater in the promotional oxidation processing device 20. [ The ultraviolet irradiation amount of the ultraviolet irradiation device 40 is preferably 0.2 to 4.0 kw / m 3 as the lamp power per waste water amount.

In the facilitated oxidation apparatus 20 having such a constitution, 1,4-dioxane in the influent wastewater is oxidatively decomposed by the accelerated oxidation method using ozone gas and ultraviolet rays in combination. In addition to the combination of ozone gas and ultraviolet ray irradiation, the accelerated oxidation method may use a combination of ozone gas and hydrogen peroxide, or a combination of ozone gas, ultraviolet ray irradiation, and hydrogen peroxide as long as ozone gas is generated in the treatment tank. When hydrogen peroxide is applied, it is preferable to inject 0.01 to 0.5 times the amount of the ozone gas as the inflow amount.

The scrubber apparatus 50 serving as the aqueous solution means of the first embodiment mainly has a feed pump 52, a sprayer 54, and an exhaust pump 58 as main components. The scrubber device (50) has a filter element (56) mounted below the casing (51). The filter medium 56 is disposed in a direction crossing the flow path of the waste gas. The atomizer 54 is mounted above the filter medium 56 in the casing 51. The sprayer 54 is provided with a water feed pump 52, and in the first embodiment, water is sprayed. An ozone waste gas pipe 59 is connected to the upper portion of the casing 51. An exhaust pump 58 is mounted on the ozone waste gas pipe 59 and waste gas of ozone is introduced into the ozone treatment device 60. A waste water pipe of an aqueous solution of 1,4-dioxane is installed in the lower part of the casing 51 so that an aqueous solution of 1,4-dioxane can be introduced into the storage tank 12.

The water supplied from the water feed pump 52 in the casing 51 is sprayed to the lower filter member 56 by the sprayer 54. In the scrubber device 50, On the other hand, the waste gas supplied from the accelerated oxidation processing apparatus 20 flows upward in the direction of the suction force of the exhaust pump 58, is discharged from above by contacting the sprayed water through the filter medium 56. The water sprayed from the sprayer 54 is discharged through the waste water pipe 53 from the bottom of the scrubber device 50 to the storage tank 12 as an aqueous solution of 1,4-dioxane.

The ozone treatment device 60 is an apparatus for decomposing ozone gas contained in waste gas using a catalyst such as activated carbon.

A method of treating 1,4-dioxane using the treatment apparatus 10 of the first embodiment with the above-described configuration is performed as follows.

First, wastewater containing 1,4-dioxane temporarily stored in the storage tank 12 is introduced into the promoted oxidation processing apparatus 20. Ozone gas is generated from the bottom portion through the diffuser 36 by the ozone generator 32 and the ultraviolet rays are radiated by the ultraviolet irradiator 40 in the accelerated oxidation apparatus 20 in which a predetermined amount of wastewater is stored . The decomposition of 1,4-dioxane is carried out by reaction with an OH radical (hydroxy radical) generated by the decomposition of ozone by ultraviolet rays. As a result, the wastewater is subjected to a pretreatment oxidation treatment using ozone treatment and ultraviolet irradiation in combination with a batch treatment, and the strong oxidative decomposition decomposes the 1,4-dioxane in the wastewater.

In the accelerated oxidation treatment apparatus 20, 1,4-dioxane is subjected to a treatment with sulfuric acid at the same time as the decomposition treatment with 1,4-dioxane. 1,4-dioxane is volatile at room temperature. In the acid treatment of 1,4-dioxane, a part of 1,4-dioxane is easily formed from wastewater by the ozone gas generated in the treatment tank and becomes waste gas in the treatment tank together with ozone gas. The unreacted ozone gas and the 1,4-dioxane waste gas generated in the accelerated oxidation processing apparatus 20 are discharged from the upper portion of the treatment tank by the waste gas pump 28 through the exhaust pipe 26 to the scrubber apparatus 50 .

In the scrubber device 50, the water supplied from the water supply pump 52 in the casing 5 is sprayed by the sprayer 54 to the lower filter member 56. The unreacted ozone gas and the waste gas of 1,4-dioxane introduced from the accelerated oxidation treatment device 20 are introduced into the casing 51 from below the filter material 56. The waste gas flows upward in accordance with the suction force of the exhaust pump 58 and is discharged from the upper side in contact with the water sprayed through the filter material 56. Since 1,4-dioxane is apt to dissolve in water, 1,4-dioxane contained in the waste gas is positively dissolved in the sprayed water to become an aqueous solution, that is, an aqueous solution of 1,4-dioxane. The aqueous solution of 1,4-dioxane is introduced into the storage tank 12 through the waste water pipe 53 and can be subjected to the facilitated oxidation treatment again in the promoted oxidation treatment apparatus 20.

On the other hand, the waste gas containing ozone gas is sent to the ozone treatment device 60 by the exhaust pump 58, and decomposed by a catalyst such as activated carbon. Since the ozone gas is harmful and corrosive, the ozone decomposition treatment may be first performed on the waste gas discharged from the promotional oxidation apparatus 20 by a catalyst such as activated carbon in the ozone treatment apparatus 60. Since the waste gas containing 1,4-dioxane can not be decomposed by the catalyst, waste gas may be introduced into the scrubber device 50 to decompose 1,4-dioxane .

According to the treatment method and apparatus of the first embodiment, 1,4-dioxane contained in the waste gas discharged in the accelerated oxidation process can be efficiently recovered And there is no possibility of being released into the atmosphere.

2 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the second embodiment. The treatment apparatus 10A of the second embodiment uses treated water treated by the accelerated oxidation treatment apparatus 20 with water sprayed from the scrubber apparatus 50. [ The rest of the configuration is the same as that of the processing apparatus 10 of the first embodiment, and the same reference numerals are given thereto, and detailed description thereof is omitted. In the treatment apparatus of the first embodiment, water used as water to be sprayed in the scrubber apparatus is used. As a medium for aqueous solution of 1,4-dioxane, it is readily available. However, in consideration of the water treatment efficiency of the entire treatment system, the use of water outside the treatment system is not efficient because water to be treated in the treatment system is increased. Therefore, as shown in the figure, a part of the treated water subjected to the decomposition treatment of 1,4-dioxane is used as the acid water.

According to the treatment method and apparatus of the second embodiment, since 1,4-dioxane and water to be dissolved are not newly used, the total amount of treated water is not increased and the cost can be reduced.

3 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the third embodiment. The treatment apparatus 10B of the third embodiment uses a biological treatment apparatus that uses the waste gas as an acid gas in a biological treatment tank of another line as an aqueous solution of 1,4-dioxane. The other structures are the same as those of the processing apparatus of the first embodiment, and are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The biological treatment device 62 is a treatment tank of another line into which raw water different from the treatment process of the storage tank 12 and the facilitated oxidation treatment device 20 is introduced. The biological treatment apparatus 62 is provided with a wing organ 64 at the bottom. The exhaust pipe (64) is connected to the exhaust pipe (26) of the accelerated oxidation processing device (20). As a result, the raw water flowing into the treatment tank is aerated to be in an aerobic state. In the treatment tank, there is an organic decomposing bacteria which decomposes the organic matter biologically. As the organic decomposing bacteria, aerobic bacteria commonly used for oxidative decomposition of BOD or COD can be used. As an example, activated sludge of a sewage treatment plant can be used. When the raw water is sewage, the organic matter-decomposing bacteria are not particularly required to be supplied with activated sludge because they are contained in the raw water supplied to the treatment tank as floating sludge. Alternatively, the activated sludge may be introduced into the treatment tank as a carrier which is covered or attached to the immobilizing material. Furthermore, a fixed bed may be provided in the treatment tank, and the activated sludge may be attached to the fixed bed as a biofilm. In addition to this, 1,4-dioxane-degrading bacteria may also be used as the organic substance-degrading bacteria.

In the treatment apparatus 10B of the third embodiment with the above configuration, a predetermined amount of raw water flows into the treatment tank. The unreacted ozone gas and the waste gas of 1,4-dioxane generated in the promoting oxidation apparatus 20 are introduced into the exhaust pipe 64 as an air-aeration gas by the waste gas pump 28. In the treatment tank, the organic matter-decomposing bacteria and the raw water are brought into contact with each other under the aerobic condition by the air aeration of the waste gas by the waste tube (64). As a result, the organic matter in the raw water is oxidatively decomposed. At the same time, the waste gas containing ozone gas and 1,4-dioxane aeration causes 1,4-dioxane to be easily dissolved in raw water because of its property of being soluble in water. When ozone gas is simultaneously contained, ozone gas can also be dissolved in the raw water, and 1,4-dioxane and ozone gas can be simultaneously treated. The dissolved ozone gas in the raw water is decomposed and removed by reacting with organic substances and the like in the wastewater. As the ozone gas is decomposed and the organic material is decomposed, the biological treatment efficiency can also be increased. In addition, when 1,4-dioxane-degrading bacteria are used as organic-decomposing bacteria, 1,4-dioxane can be decomposed and treated in the treatment tank.

According to the treatment apparatus of the third embodiment, it is not necessary to newly install an apparatus such as a scrubber in order to make 1,4-dioxane aqueous solution, and the cost of the entire apparatus can be reduced.

4 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the fourth embodiment. The treatment apparatus 10C of the fourth embodiment uses a biological treatment apparatus provided at the front end of the storage tank 12 and the accelerated oxidation treatment apparatus 20 as means for aqueous solution of 1,4-dioxane. The other structures are the same as those of the processing apparatus 10 of the first embodiment, and are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The biological treatment apparatus 62A is disposed at the front end of the storage tank 12. [ The biological treatment apparatus 62A, similarly to the biological treatment apparatus 62 of the third embodiment, is provided with a wick organ 64A in the treatment tank. The exhaust pipe 64A is connected to the exhaust pipe 26 of the accelerated oxidation processing apparatus 20. [ Inside the treatment tank, there are organic decomposing bacteria that decompose organic matter biologically. As the organic decomposing bacteria, aerobic bacteria commonly used for oxidative decomposition of BOD or COD can be used.

In the treatment apparatus 10C of the fourth embodiment according to the above configuration, a predetermined amount of raw water flows into the treatment tank of the biological treatment apparatus 62A. The unreacted ozone gas and the waste gas of 1,4-dioxane generated in the accelerated oxidation processing apparatus 20 are introduced into the exhaust pipe 64A by the waste gas pump 28 as an air-aeration gas. In the treatment tank, the organic matter-decomposing bacteria and the raw water come into contact with each other under an aerobic condition by the air aeration of the waste gas by the waste tube 64A. As a result, the organic matter in the raw water is oxidatively decomposed. At the same time, the waste gas containing ozone gas and 1,4-dioxane aeration causes 1,4-dioxane to be easily dissolved in raw water because of its property of being soluble in water. When ozone gas is simultaneously contained, ozone gas can also be dissolved in the raw water, and 1,4-dioxane and ozone gas can be simultaneously treated. The dissolved ozone gas in the raw water is decomposed and removed by reacting with organic substances and the like in the wastewater. As the ozone gas is decomposed and the organic material is decomposed, the biological treatment efficiency can also be increased. The first treated water subjected to the biological treatment in the biodegradation treatment device is introduced into the next storage tank 12. In the biological treatment apparatus 62A, 1,4-dioxane dissolved in water can not be decomposed by biological treatment using conventional organic decomposing bacteria. Therefore, most of the 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the first treatment water. Then, in the same manner as in the first embodiment, the promoted oxidation treatment apparatus 20 performs the decomposition treatment of 1,4-dioxane, and is discharged to the outside of the system as the second treated water. On the other hand, the unreacted ozone gas generated in the treatment tank and the waste gas containing 1,4-dioxane are used as a gas for air-aeration in the biological treatment apparatus in the front end.

When 1,4-dioxane-degrading bacteria are used as the organic-decomposing bacteria, 1,4-dioxane can also be decomposed in the treatment tank of the biological decomposition apparatus 62A.

According to the treatment method and apparatus of the fourth embodiment, there is no need to newly install a device such as a scrubber in order to make 1,4-dioxane aqueous solution. By using a biological treatment tank on the same line as the accelerated oxidation process, the cost of the apparatus can be reduced.

5 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the fifth embodiment. The treatment apparatus 10D of the fifth embodiment uses a plurality of biological treatment apparatuses provided at the front end of the storage tank 12 and the facilitated oxidation treatment apparatus 20 as a means for aqueous solution of 1,4-dioxane . The rest of the configuration is the same as that of the processing apparatus 10 of the first embodiment, and the same reference numerals are given thereto, and detailed description thereof is omitted. The biological treatment apparatus of the fifth embodiment is composed of a first biological treatment apparatus 70 and a second biological treatment apparatus 72 in detail. In addition, the biological treatment tank may be configured to have three or more biological treatment units arranged according to the biological treatment process. The first biological treatment apparatus 70, like the biological treatment apparatus according to the third embodiment, is provided with a wing organ 64B in the treatment tank. The exhaust pipe 64B is connected to the exhaust pipe 26 of the promotional oxidation apparatus 20. Inside the treatment tank, there are organic decomposing bacteria that decompose organic matter biologically. As the organic decomposing bacteria, aerobic bacteria commonly used for oxidative decomposition of BOD or COD can be used. The second biological treatment apparatus 72 is provided with a breather 64C in the treatment tank. A blower 65 is connected to the blowing unit 64C, and is configured to be capable of supplying an air-aeration gas. Inside the treatment tank, there are organic decomposing bacteria that decompose organic matter biologically. As the organic decomposing bacteria, aerobic bacteria commonly used for oxidative decomposition of BOD or COD can be used.

In the treatment apparatus 10D of the fifth embodiment with the above-described configuration, a predetermined amount of raw water flows into the treatment tank of the first biological treatment apparatus 70. [ The unreacted ozone gas and the off gas of 1,4-dioxane generated in the promoting oxidation apparatus 20 are introduced into the exhaust pipe 64B by the waste gas pump 28 as an air-aeration gas. In the treatment tank, the organic-decomposing bacteria and the raw water come into contact with each other under the aerobic condition by the air aeration of the waste gas by the waste tube 64B. At the same time, the waste gas containing ozone gas and 1,4-dioxane aeration causes 1,4-dioxane to be easily dissolved in raw water because of its property of being soluble in water. Also, when ozone gas is contained at the same time, ozone gas can also be dissolved in the raw water. However, when the amount of ozone gas in the waste gas is large, the biological activity is lowered, and thus the environment becomes difficult to proceed with biological treatment. Therefore, in the first biological treatment apparatus 70, mainly, the ozone gas is decomposed and removed by reacting with organic substances and the like in the wastewater, thereby lowering the ozone concentration. The first treated water treated in the first biological treatment apparatus 70 is introduced into the second biological treatment apparatus 72 in the subsequent stage. In the second biological treatment apparatus 72, since the ozone concentration is lower than that of the first biological treatment apparatus 70, the biological activity becomes high. Thus, the organic-decomposing bacteria and the first process water are brought into contact with each other under the aerobic condition by the air vent by the blowing device 64C, and the organic matter in the first process water is oxidatively decomposed.

The second treated water subjected to the biological treatment in the second biological treatment apparatus 72 is introduced into the later-stage storage tank 12. In the first biological treatment apparatus 70, 1,4-dioxane dissolved in water can not be decomposed by biological treatment using conventional organic decomposing bacteria. For this reason, most of the 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the second treatment water. Then, in the same manner as in the first embodiment, the decomposition treatment of 1,4-dioxane is carried out in the accelerated oxidation treatment apparatus 20, and is discharged to the outside of the system as third treated water. On the other hand, the unreacted ozone gas generated in the treatment tank and the waste gas containing 1,4-dioxane are used as the gas for the air-aeration of the first biological treatment apparatus 70 at the front end.

Further, when 1,4-dioxane-degrading bacteria are used as the organic decomposing bacteria of the second biological treatment apparatus 72, 1,4-dioxane can be decomposed and treated in the treatment tank.

According to the treatment method and apparatus of the fifth embodiment, when unreacted ozone gas is abundant in the waste gas, the biological activity of the biological treatment tank may be lowered, but the concentration of ozone in the plurality of biological treatment tanks So that a biological treatment environment suitable for biological treatment can be formed. Therefore, the influence of the ozone gas on the organic-decomposing bacteria can be suppressed.

6 is a schematic view of the configuration of an apparatus for treating 1,4-dioxane in wastewater according to the sixth embodiment. The treatment apparatus 10E of the sixth embodiment is similar to the treatment apparatus 10C of the fourth embodiment except that the raw water treatment process is the same as that of the treatment apparatus 10C of the first embodiment, The scrubber device 50 of the scrubber 10 is used.

Specifically, in the treatment apparatus 10E of the sixth embodiment, raw water is introduced into the biological treatment apparatus 62B. The biological treatment apparatus 62B has a wick organ 64C in the treatment tank. A blower 65 is connected to the blowing unit 64C, and is configured to be capable of supplying an air-aeration gas. Inside the treatment tank, there are organic decomposing bacteria that decompose organic matter biologically. The aqueous solution of 1,4-dioxane in the scrubber device 50 is introduced into the biological treatment device 62B.

In the treatment apparatus of the sixth embodiment with the above configuration, a predetermined amount of raw water flows into the treatment tank of the biological treatment apparatus 62B. In the biological treatment apparatus 62B, the organic matter-decomposing bacteria and the first treatment water are brought into contact with each other under the aerobic condition by the air aeration by the wick 64C, and the organic matter in the raw water is oxidatively decomposed. An aqueous solution of 1,4-dioxane formed in the scrubber apparatus 50 is introduced into the biological treatment apparatus 62B.

The first treated water subjected to the biological treatment in the biological treatment apparatus 62B is introduced into the later-stage storage tank 12. In the biological treatment apparatus 62B, 1,4-dioxane dissolved in water can not be decomposed by biological treatment using conventional organic decomposing bacteria. Therefore, most of the 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the first treatment water. Then, in the same manner as in the first embodiment, the promoted oxidation treatment apparatus 20 performs the decomposition treatment of 1,4-dioxane, and is discharged to the outside of the system as the second treated water. On the other hand, waste gas containing unreacted ozone gas and 1,4-dioxane generated in the treatment tank is discharged from the upper part of the promotional oxidation apparatus 20 by the waste gas pump 28 through the exhaust pipe 26, And introduced into the scrubber device 50.

In the scrubber device 50, the water supplied from the water supply pump 52 in the casing 51 is sprayed to the lower filter material 56 by the sprayer 54. The unreacted ozone gas and the waste gas of 1,4-dioxane introduced from the accelerated oxidation treatment device 20 are introduced into the casing 51 from below the filter material 56. The waste gas flows upward in accordance with the suction force of the exhaust pump 58 and is discharged from above by contacting the sprayed water through the filter material 56. Since 1,4-dioxane is apt to dissolve in water, 1,4-dioxane contained in the waste gas is positively dissolved in the sprayed water to become an aqueous solution, that is, an aqueous solution of 1,4-dioxane. An aqueous solution of 1,4-dioxane is introduced into the front end biological treatment apparatus 62B. Then, the accelerated oxidation treatment can be performed again in the accelerated oxidation treatment apparatus 20. [ On the other hand, the waste gas containing ozone gas is sent to the ozone treatment device 60 by the exhaust pump 58 and decomposed by a catalyst such as activated carbon.

According to the processing method and apparatus of the sixth embodiment, the ozone gas which may corrode the pipe can be separated and removed from the 1,4-dioxane in the scrubber apparatus. Therefore, ozone gas is not introduced into the biological treatment apparatus, so there is no fear of corrosion of the piping connected to the treatment tank, and deterioration of the entire apparatus over the aged can be prevented.

[Example 1]

In the treatment apparatus 10 of the first embodiment, an example in which 1,4-dioxane in wastewater is treated will be described below. In the accelerated oxidation processing apparatus 20, a low-pressure mercury lamp with a lamp power of 48 W which is to be the ultraviolet irradiating device 40 was charged into a treatment vessel of 12 L having a cylindrical inner volume. The irradiation dose of the ultraviolet lamp at this time is 4 kw / m 3. The ozone treatment device 30 passed ozone gas having a gas concentration of 20 mg / L at the gas flow rate of 5 L / min from the lower part of the treatment tank. The retention time in the treatment tank was set to 2 hours, and the raw water was introduced into the treatment tank from the lower introduction pipe 22 with the pump 14.

In the wastewater of this example, treated water obtained by biological treatment of A factory wastewater was used. The wastewater contained 200 mg / L of 1,4-dioxane and 498 mg / L of COD, and contained organic substances other than 1,4-dioxane.

The amount of 1,4-dioxane in the promoted oxidation-treated water is 8 mg / L to 12 mg / L, 95% of the 1,4-dioxane is removed by oxidative decomposition or acid, About 5% of the oxalic acid was flowing out of the treated water. At this time, the concentration of 1,4-dioxane in the waste gas was measured and the amount of 1,4-dioxane formed was calculated. As a result, it was found that about 8% of 1,4-dioxane was produced. In addition, 15% of the incoming ozone gas remained unreacted and contained in the waste gas.

As a result of treating the waste gas containing 1,4-dioxane with the scrubber apparatus 50, it was found that the amount of 1,4-dioxane discharged from the treated gas after the scrubber treatment can be reduced to less than 0.8%.

In this regard, in the conventional accelerated oxidation treatment apparatus, about 8% of 1,4-dioxane is produced and released to the atmosphere. However, by using the treatment apparatus 10 of the present embodiment, The amount of 1,4-dioxane emitted to the outside can be greatly reduced.

The mass balance of the accelerated oxidation treatment apparatus is as follows.

In the conventional facilitated oxidation treatment apparatus, the treated water was 5 and the calculated acid was 8 for the raw water 100. In the treatment apparatus of the present embodiment, the number of treatments was 5 and the ratio of acids was 0.8 for raw water 100.

In addition, the concentration of ozone gas in the treated gas after the scrubber treatment is reduced to about 1/3 of that before the treatment, thereby making it possible to reduce the burden on the waste ozone gas treatment.

[Example 2]

In the treatment apparatus of the third embodiment, an example in which 1,4-dioxane in wastewater is treated will be described below. The biological treatment device 62 is a BOD treatment device that does not contain 1,4-dioxane and treats wastewater having a BOD concentration of about 1200 mg / L as a retention time of 24 hours. In the reaction tank, a contact material made of plastic for holding the organism is charged.

As in the first embodiment, the operating conditions of the raw water and the promoted oxidation treatment apparatus are different only in the treatment method of the waste gas. The waste gas was connected to a line for supplying an air-venting gas (air, oxygen) to the biological treatment device 62 to supply waste gas containing ozone gas and 1,4-dioxane. As a result, the concentration of 1,4-dioxane calculated and discharged from the biological treatment apparatus 62 can be detected, and thus it is possible to prevent the generation of acid. In addition, waste ozone gas could be treated up to 0.1 mg / L or less. Therefore, an apparatus for treating waste ozone gas becomes unnecessary.

[Example 3]

In the treatment apparatus of the fifth embodiment, an example in which 1,4-dioxane in wastewater is treated will be described below. The COD of the A factory wastewater was 2010 mg / L, and it was able to treat up to 498 mg / L by biological treatment in the first biological treatment apparatus 70, and the concentration of 1,4-dioxane was 200 mg / L 1). The waste ozone gas could be treated up to 0.1 mg / L or less. Therefore, an apparatus for treating waste ozone gas becomes unnecessary.

In the second biological treatment apparatus 72, a base acid of 1,4-dioxane was confirmed, unlike the case of Example 2, because the base acid was originally generated by aeration. There was almost no increase in the amount of production. In this respect, it was confirmed that the present invention is effective for the treatment of 1,4-dioxane calculated by the accelerated oxidation treatment apparatus and the treatment of waste ozone gas.

10, 10A, 10B, 10C, 10D, 10E: Apparatus for treating 1,4-dioxane in wastewater
12: Storage tank
14: Pump
20: Facilitated oxidation treatment device
22: introduction pipe
24: Derivative tube
26: Exhaust pipe
28: Waste gas pump
30: Ozone treatment device
32: ozone generator
34: ozone gas injection tube
36: live organ
40: ultraviolet irradiator
50: scrubber device
51: casing
52: Feed pump
53: Wastewater pipe
54: atomizer
56: Filter medium
58: Exhaust pump
59: ozone waste gas pipe
60: ozone treatment device
62, 62A: biological treatment device
64, 64A, 64B, 64C:
65: Blower
70: First biological treatment device
72: Second biological treatment device

Claims (14)

Containing at least one of 1,4-dioxane calculated together with ozone gas generated in an accelerated oxidation process for decomposing 1,4-dioxane contained in wastewater by using at least one of ozone treatment, hydrogen peroxide treatment and ultraviolet ray treatment Is dissolved in water to make the 1,4-dioxane aqueous solution,
Wherein the aqueous solution is sprayed to the flow path of the waste gas in the casing by a scrubber equipped with the sprayer of water in the casing so that the waste gas and the water are brought into gas-liquid contact with each other. Dioxane. delete The method according to claim 1,
Wherein the water supplied to the scrubber uses treated water treated in the accelerated oxidation step. Containing at least one of 1,4-dioxane calculated together with ozone gas generated in an accelerated oxidation process for decomposing 1,4-dioxane contained in wastewater by using at least one of ozone treatment, hydrogen peroxide treatment and ultraviolet ray treatment Is dissolved in water to make the 1,4-dioxane aqueous solution,
The aqueous solution may be prepared by using the waste gas as an acid gas for an acid treatment in a biological treatment process in a different line from the treatment line including the accelerated oxidation process and dissolving the 1,4- Lt; RTI ID = 0.0 > 1,4-dioxane < / RTI > in wastewater. Containing at least one of 1,4-dioxane calculated together with ozone gas generated in an accelerated oxidation process for decomposing 1,4-dioxane contained in wastewater by using at least one of ozone treatment, hydrogen peroxide treatment and ultraviolet ray treatment Is dissolved in water to make the 1,4-dioxane aqueous solution,
The aqueous solution is characterized in that the waste gas is used as an acid gas for the biological treatment step in the preceding stage of the facilitated oxidation step and the 1,4-dioxane is dissolved in the treated water of the biological treatment step Lt; RTI ID = 0.0 > 1,4-dioxane < / RTI > 6. The method of claim 5,
Wherein the biological treatment step is carried out in a plurality of biological treatment tanks arranged in series in front of the accelerated oxidation step. The method of claim 3,
Wherein the 1,4-dioxane discharged from the scrubber is introduced into a biotreatment step in the upstream of the accelerated oxidation process. Accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater by using at least one of ultraviolet rays, hydrogen peroxide water and an alkaline solution and ozone gas,
And an aqueous solution of 1,4-dioxane for contacting the waste gas containing 1,4-dioxane, which is generated together with the ozone gas, in the accelerated oxidation process of the accelerated oxidation means with water,
The aqueous solution of 1,4-dioxane is a scrubber which has an atomizer for water in the casing and sprays the waste gas through the atomizer in the flow path of the waste gas in the casing to vapor-liquid contact the waste gas and the water. Gt; of 1,4-dioxane in wastewater. delete 9. The method of claim 8,
Wherein the water supplied to the scrubber uses treated water treated with the accelerated oxidation means. Accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater by using at least one of ultraviolet rays, hydrogen peroxide water and an alkaline solution and ozone gas,
And an aqueous solution of 1,4-dioxane for contacting the waste gas containing 1,4-dioxane, which is generated together with the ozone gas, in the accelerated oxidation process of the accelerated oxidation means with water,
Wherein the means for aqueous solution of 1,4-dioxane is a biological treatment means using the waste gas as an oxidizing gas in a biological treatment tank of a different line from the treatment line including the accelerated oxidation means. 4-dioxane treatment apparatus. Accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater by using at least one of ultraviolet rays, hydrogen peroxide water and an alkaline solution and ozone gas,
And an aqueous solution of 1,4-dioxane for contacting the waste gas containing 1,4-dioxane, which is generated together with the ozone gas, in the accelerated oxidation process of the accelerated oxidation means with water,
Wherein the means for aqueous solution of 1,4-dioxane is a biological treatment means using the waste gas as an oxidizing gas in the biological treatment tank at the upstream side of the accelerated oxidation means. Device. 13. The method of claim 12,
Wherein the biological treatment means is performed in a plurality of biological treatment tanks arranged in series in front of the accelerated oxidation means. 9. The method of claim 8,
Wherein the 1,4-dioxane discharged from the scrubber is introduced into the biological treatment means at the upstream side of the accelerated oxidation means.

Images