JP5808663B2 - Method and apparatus for treating 1,4-dioxane in wastewater - Google Patents

Description

  The present invention particularly relates to a method and apparatus for treating 1,4-dioxane in wastewater containing 1,4-dioxane for treating 1,4-dioxane in wastewater by an accelerated oxidation method (AOP method) using ozone gas. About.

  1,4-dioxane is generally used as a solvent or the like, and in particular, is often used as a solvent for a paint or the like. It is also contained in detergents such as commercially available polyoxyalkyl ethers. For this reason, 1,4-dioxane is passed through the factory wastewater of the manufacturing factory which manufactures 1,4-dioxane or the manufacturing factory which manufactures polyoxyalkyl ether, and domestic wastewater using the detergent containing polyoxyalkyl ether. Is discharged into sewage.

However, since 1,4-dioxane is a water-soluble hardly decomposable substance, it can hardly be decomposed by biological treatment or solid-liquid separation treatment in a sewage treatment plant, and there is a concern about pollution to the water environment.
On the other hand, 1,4-dioxane has been detected in a wide range in environmental pollution surveys of designated chemical substances conducted by the Environment Agency, and pollution in water environments such as rivers and lakes has been reported. In addition, an example in which a high concentration of dioxane was detected from groundwater has been reported.

  From such a background, with the amendment of the Water Supply Law in April 2004, the content of setting the regulated value of 1,4-dioxane to 0.05 mg / L as a drinking water standard was introduced. Furthermore, an environmental standard value was established in November 2010, and a treatment technique for efficiently decomposing and removing 1,4-dioxane in wastewater is desired.

  Conventionally, as a method for decomposing and removing 1,4-dioxane in wastewater, for example, an accelerated oxidation method that promotes formation of OH radicals by mainly using ozone treatment in combination with hydrogen peroxide treatment and ultraviolet treatment has been proposed. (For example, Patent Documents 1 to 3).

JP 2001-29966 A JP 2001-121163 A JP 2000-202466 A

  However, since the ozone treatment of the accelerated oxidation method diffuses ozone gas from the lower part of the treatment tank and supplies it into the tank, a part of 1,4-dioxane in the wastewater is caused by gas (bubbles) containing ozone gas. , Will diffuse from liquid to gas.

  FIG. 7 is a graph showing the removal effect of 1,4-dioxane by weak aeration. The graph is a measurement of the concentration of 1,4-dioxane when a 12 L reactor was aerated at 2 l / min. In the figure, the horizontal axis indicates the aeration time (Hr), and the vertical axis indicates the 1,4-dioxane concentration (mg / L). In FIG. 7, only the aeration process is performed, and the decomposition process of 1,4-dioxane is not performed. As shown in the figure, 1,4-dioxane (235 mg / L) before the start of the aeration process is reduced to about 180 mg / L when the aeration process is performed for about 140 hours. Due to the aeration treatment, 1,4-dioxane in the aqueous solution is diffused and released into the atmosphere. 1,4-Dioxane is a substance harmful to the human body, and its release into the atmosphere needs to be reduced as much as possible.

  Further, in the accelerated oxidation method, not all ozone gas can be used, and ozone gas of about 3 to 20% of the injection amount is discharged as exhaust gas, although it depends on conditions such as water depth. Ozone gas is harmful to the human body, and it is necessary to decompose and remove this ozone gas, which 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 expensive.

  Therefore, in order to solve the above-mentioned problems of the prior art, the present invention reduces the release of 1,4-dioxane into the atmosphere when treating wastewater containing 1,4-dioxane by the accelerated oxidation method using ozone gas. It aims at providing the processing method and apparatus of 1, 4- dioxane in wastewater which can be reduced efficiently.

The treatment method of 1,4-dioxane in wastewater of the present invention decomposes 1,4-dioxane contained in wastewater by using one or more of ozone treatment and hydrogen peroxide treatment or ultraviolet treatment. The waste gas containing the 1,4-dioxane diffused together with the ozone gas generated in the accelerated oxidation step is dissolved in water to make the 1,4-dioxane into an aqueous solution.
Thereby, 1,4-dioxane contained in the waste gas discharged in the accelerated oxidation process using ozone gas can be efficiently recovered, and there is no possibility of being released to the atmosphere.

The aqueous solution is formed by spraying the waste gas flow path in the casing with the sprayer with a scrubber provided with the water sprayer in the casing to bring the waste gas and water into gas-liquid contact. It is said.
Thereby, the 1, 4- dioxane diffused with ozone gas can be made into an aqueous solution efficiently, and there is no possibility of corrosion of piping by ozone gas.

The water supplied to the scrubber is characterized by using treated water treated in the accelerated oxidation step.
Thereby, since it is not necessary to supply newly the water which melt | dissolves 1, 4- dioxane from the outside, the total amount of treated water is not increased and cost reduction of the whole decomposition process can be achieved.

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 aeration gas in a biological treatment process separate from the treatment line including the accelerated oxidation process. It is characterized by that.
Thereby, in order to make 1,4-dioxane into aqueous solution, it is not necessary to newly provide apparatuses, such as a scrubber. Therefore, the cost of the entire 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 aeration gas in the biological treatment process preceding the accelerated oxidation process. .
Thereby, in order to make 1,4-dioxane into aqueous solution, it is not necessary to newly provide apparatuses, such as a scrubber. By using the biological treatment tank on the same line as the accelerated oxidation process, the cost of the entire apparatus can be reduced.

The biological treatment process is performed in a plurality of biological treatment tanks arranged in series before the accelerated oxidation process.
Thereby, the ozone concentration of the biological treatment tank on the downstream side can be set lower than the ozone concentration of the biological treatment tank on the upstream side, and a biological treatment environment suitable for biological treatment can be formed.

The 1,4-dioxane discharged from the scrubber is introduced into a biological treatment process preceding the accelerated oxidation process.
Thereby, there is no possibility that ozone corrodes piping while introducing ozone gas into a biological treatment tank. Therefore, the discharge of 1,4-dioxane to the outside of the system can be reduced, and deterioration of the entire apparatus over time can be prevented.

The apparatus for treating 1,4-dioxane in wastewater according to the present invention is a 1,4-dioxane contained in wastewater by using any one or more of ultraviolet rays, hydrogen peroxide solution, alkaline solution, and ozone gas. Accelerated oxidizing means for decomposing dioxane, and 1,4-dioxane aqueous solution means for bringing waste gas containing 1,4-dioxane diffused together with the ozone gas generated in the accelerating oxidation step of the accelerating oxidizing means into contact with water It is characterized by having.
Thereby, 1,4-dioxane contained in the exhaust gas discharged in the accelerated oxidation step can be efficiently recovered, and there is no possibility of being released to the atmosphere.

The aqueous solution of 1,4-dioxane includes the water sprayer in a casing, and water is sprayed to the waste gas flow path in the casing by the sprayer to bring the waste gas and water into gas-liquid contact. It is characterized by being a scrubber.
Thereby, the 1, 4- dioxane diffused with ozone gas can be made into an aqueous solution efficiently, and there is no possibility of corrosion of piping by ozone gas.

The water supplied to the scrubber is characterized by using treated water treated by the accelerated oxidation means.
Thereby, since it is not necessary to supply the water which melt | dissolves 1, 4- dioxane from the outside newly, the total amount of process water is not increased and cost reduction of the whole process can be achieved.

The 1,4-dioxane aqueous solution means is a biological treatment means that uses the waste gas as an aeration gas to a biological treatment tank that is separate from the treatment line including the accelerated oxidation means.
Thereby, in order to make 1,4-dioxane into aqueous solution, it is not necessary to newly provide apparatuses, such as a scrubber. Therefore, the cost of the entire apparatus can be reduced.

The 1,4-dioxane aqueous solution means is a biological treatment means that uses the waste gas as an aeration gas in a biological treatment tank upstream of the accelerated oxidation means.
Thereby, in order to make 1,4-dioxane into aqueous solution, it is not necessary to newly provide apparatuses, such as a scrubber. By using a biological treatment tank on the same line as the accelerated oxidation process, the cost of the apparatus can be reduced.

The biological treatment means is performed in a plurality of biological treatment tanks arranged in series before the promoted oxidation means.
Thereby, the ozone concentration of the biological treatment tank on the downstream side can be set lower than the ozone concentration of the biological treatment tank on the upstream side, and a biological treatment environment suitable for biological treatment can be formed.

The 1,4-dioxane discharged from the scrubber is introduced into a biological treatment means preceding the accelerated oxidation means.
Thereby, there is no possibility that ozone corrodes piping while introducing ozone gas into a biological treatment tank. Therefore, the discharge of 1,4-dioxane to the outside of the system can be reduced, and deterioration of the entire apparatus over time can be prevented.

  According to the method and apparatus for treating 1,4-dioxane in wastewater of the present invention having the above-described configuration, 1,4-dioxane contained in the exhaust gas discharged in the accelerated oxidation step can be easily and efficiently recovered. Can be released to the atmosphere.

It is a block schematic diagram of the processing apparatus of 1, 4- dioxane in the wastewater of 1st Embodiment. It is the structure schematic of the processing apparatus of the 1, 4- dioxane in the wastewater of 2nd Embodiment. It is the structure schematic of the processing apparatus of the 1, 4- dioxane in the wastewater of 3rd Embodiment. It is the structure schematic of the processing apparatus of the 1, 4- dioxane in the wastewater of 4th Embodiment. It is the structure schematic of the processing apparatus of the 1, 4- dioxane in the wastewater of 5th Embodiment. It is a structure schematic of the processing apparatus of the 1, 4- dioxane in the wastewater of 6th Embodiment. It is a graph which shows the removal effect of 1, 4- dioxane by weak aeration.

Embodiments of the method for treating 1,4-dioxane in wastewater and the apparatus thereof according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of an apparatus for treating 1,4-dioxane in wastewater according to the first embodiment. As shown in the drawing, the treatment apparatus 10 for 1,4-dioxane in wastewater according to the first embodiment (hereinafter simply referred to as the treatment apparatus 10) uses one or more of ozone treatment and hydrogen peroxide treatment or ultraviolet treatment. Then, the accelerated oxidation treatment apparatus 20 serving as an accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater with OH radicals and 1,4-gas diffused together with ozone gas generated in the accelerated oxidation process of the accelerated oxidation means A scrubber device 50 serving as an aqueous solution of 1,4-dioxane for bringing waste gas containing dioxane into contact with water has a main basic configuration.

  A storage tank 12 is disposed in the front stage of the accelerated oxidation treatment apparatus 20 of the treatment apparatus 10. The storage tank 12 temporarily stores the raw water flowing from the upstream side in consideration of fluctuations in the raw water flow rate. And the stored raw | natural water passes the introductory pipe 22 with the pump 14 of the introductory pipe 22 arrange | positioned between the storage tank 12 and the accelerated oxidation processing apparatus 20, and is sent to the subsequent accelerated oxidation processing apparatus 20. FIG.

  In the accelerated oxidation treatment apparatus 20, the raw water introduction pipe 22 is connected to the bottom surface of the treatment tank, and the treated water outlet pipe 24 is connected to the side face of the treatment tank. The accelerated oxidation treatment device 20 is provided with an ozone treatment device 30 and an ultraviolet irradiation device 40.

  The ozone treatment device 30 includes an ozone generator 32, an ozone gas injection pipe 34, and an air diffusion pipe 36. The ozone generator 32 is attached in the vicinity of the accelerated oxidation treatment 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 diffusion pipe 36 disposed at the bottom of the accelerated oxidation treatment apparatus 20. The ozone gas diffused into the wastewater is exhausted from an exhaust pipe 26 provided at the upper part of the accelerated oxidation treatment apparatus 20. In addition, as for the acceleration | stimulation oxidation processing apparatus 20, it is preferable that the ozone gas amount which will be about 10 mg / L-300 mg / L is inject | poured from the ozone processing apparatus 30 as an example.

The ultraviolet irradiation device 40 is provided in an upright state at the center of the accelerated oxidation treatment apparatus 20, and the wastewater in the accelerated oxidation treatment apparatus 20 is irradiated with ultraviolet rays having a predetermined wavelength. In addition, it is preferable that the ultraviolet irradiation amount of the ultraviolet irradiation device 40 is irradiated at 0.2 to 4.0 kw / m ³ as lamp power per waste water amount.

  In the accelerated oxidation apparatus 20 having such a configuration, 1,4-dioxane in the inflowing wastewater is oxidatively decomposed by an accelerated oxidation method using ozone gas and ultraviolet rays in combination. In addition to the combination of ozone gas and ultraviolet irradiation, the accelerated oxidation method may be a combination of ozone gas and hydrogen peroxide or ozone gas, ultraviolet irradiation and hydrogen peroxide as long as ozone gas is diffused in the treatment tank. A combination of these can also be used. In addition, when hydrogen peroxide is applied, it is preferable that 0.01 to 0.5 times the ozone gas injection amount is injected as the inflow amount.

  The scrubber device 50 serving as the aqueous solution means of the first embodiment has a water supply pump 52, a sprayer 54, and an exhaust pump 58 as the main basic components. The scrubber device 50 has a filter medium 56 attached to the lower side in the casing 51. The filter medium 56 is disposed in a direction crossing the waste gas flow path. The sprayer 54 is attached above the filter medium 56 in the casing 51. The sprayer 54 is provided with a water supply pump 52, and in the first embodiment, tap water is sprayed. Above the casing 51, an ozone waste gas pipe 59 is connected. An exhaust pump 58 is attached to the ozone waste gas pipe 59, and ozone waste gas is introduced into the ozone treatment apparatus 60. A wastewater pipe of an aqueous solution of 1,4-dioxane is attached to the lower portion of the casing 51 so that the aqueous solution of 1,4-dioxane can be introduced into the storage tank 12.

  In the scrubber device 50, the water supplied from the water supply pump 52 in the casing 51 is sprayed onto the lower filter medium 56 by the sprayer 54. On the other hand, the waste gas supplied from the accelerated oxidation treatment apparatus 20 flows upward due to the suction force of the exhaust pump 58, comes into contact with the water sprayed through the filter medium 56, and is discharged from above. Water sprayed from the sprayer 54 is discharged from the bottom of the scrubber device 50 to the storage tank 12 as an aqueous solution of 1,4-dioxane via the waste water pipe 53.

The ozone treatment device 60 is a device that decomposes ozone gas contained in waste gas using a catalyst such as activated carbon.
The 1,4-dioxane processing method using the processing apparatus 10 according to the first embodiment having the above-described configuration is performed as follows.

  First, waste water containing 1,4-dioxane temporarily stored in the storage tank 12 is introduced into the accelerated oxidation treatment apparatus 20. In the accelerated oxidation treatment apparatus 20 in which a predetermined amount of waste water is stored, ozone gas is diffused from the bottom through the diffuser pipe 36 by the ozone generator 32, and ultraviolet rays are irradiated by the ultraviolet irradiation device 40. The decomposition of 1,4-dioxane is carried out by a reaction with OH radicals (hydroxy radicals) generated by the decomposition of ozone by ultraviolet rays. Accordingly, the waste water is subjected to accelerated oxidation treatment using both ozone treatment and ultraviolet irradiation by batch treatment, and 1,4-dioxane in the waste water is decomposed by the strong oxidative decomposition.

  In the accelerated oxidation treatment apparatus 20, 1,4-dioxane is diffused simultaneously with 1,4-dioxane decomposition treatment. 1,4-Dioxane is volatile at room temperature. In the 1,4-dioxane aeration process, a part of 1,4-dioxane is easily diffused from the waste water by the ozone gas diffused in the treatment tank, and becomes a waste gas in the treatment tank together with the ozone gas. Unreacted ozone gas and 1,4-dioxane waste gas generated in the accelerated oxidation treatment apparatus 20 are introduced into the scrubber device 50 through the exhaust pipe 26 by the waste gas pump 28 from the upper part of the treatment tank.

  In the scrubber device 50, the water supplied from the water supply pump 52 in the casing 51 is sprayed onto the lower filter medium 56 by the sprayer 54. Then, the unreacted ozone gas and 1,4-dioxane waste gas introduced from the accelerated oxidation treatment apparatus 20 are introduced into the casing 51 from below the filter medium 56. The waste gas flows upward by the suction force of the exhaust pump 58, comes into contact with the water sprayed through the filter medium 56, and is discharged from above. Since 1,4-dioxane is easily soluble in water, 1,4-dioxane contained in the waste gas is actively dissolved in the sprayed water to form an aqueous solution, that is, an aqueous solution of 1,4-dioxane. Become. The aqueous solution of 1,4-dioxane is introduced into the storage tank 12 through the wastewater pipe 53, and the accelerated oxidation treatment can be performed again by the accelerated oxidation treatment apparatus 20.

  On the other hand, 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 ozone gas is harmful and corrosive, first, the waste gas discharged from the accelerated oxidation treatment apparatus 20 may be subjected to ozone decomposition treatment using a catalyst such as activated carbon in the ozone treatment apparatus 60. Since the waste gas containing 1,4-dioxane cannot be decomposed by the catalyst, the waste gas may be introduced into the scrubber device 50 and the 1,4-dioxane may be decomposed thereafter.

  According to such a treatment method and apparatus of the first embodiment, 1,4-dioxane is easily dissolved in water, and 1,4-dioxane contained in the waste gas discharged in the accelerated oxidation treatment step is used. Dioxane can be efficiently recovered and there is no risk of being released to the atmosphere.

  FIG. 2 is a schematic configuration diagram of the apparatus for treating 1,4-dioxane in wastewater according to the second embodiment. 10 A of processing apparatuses of 2nd Embodiment use the treated water processed with the accelerated oxidation processing apparatus 20 to the water sprayed with the scrubber apparatus 50. FIG. The other configuration is the same as that of the processing apparatus 10 of the first embodiment, and the same reference numerals are given and detailed description is omitted. In the processing apparatus of 1st Embodiment, tap water is used for the water sprayed with a scrubber apparatus. As a medium for converting 1,4-dioxane into an aqueous solution, it can be easily obtained. However, considering the water treatment efficiency of the entire treatment system, using tap water outside the treatment system increases the amount of water that must be treated in the treatment system, which is not efficient. Therefore, as shown in the figure, a part of the treated water subjected to 1,4-dioxane decomposition treatment is used as the aeration water.

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

  FIG. 3 is a schematic configuration diagram of the apparatus for treating 1,4-dioxane in wastewater according to the third embodiment. The processing apparatus 10B of 3rd Embodiment is using the biological treatment apparatus which uses the said waste gas as an aeration gas to the biological treatment tank of another line as an aqueous solution means of 1, 4- dioxane. Other configurations are the same as those of the processing apparatus of the first embodiment, and the same reference numerals are given and detailed description thereof is omitted.

  The biological treatment apparatus 62 is a treatment tank in a separate line into which another raw water is introduced from the treatment process of the storage tank 12 and the accelerated oxidation treatment apparatus 20. The biological treatment device 62 includes an aeration tube 64 at the bottom. The aeration pipe 64 is connected to the exhaust pipe 26 of the accelerated oxidation processing apparatus 20. Thereby, the raw | natural water which flowed into the processing tank is aerated by air-aerobic. In addition, the treatment tank has organic matter-degrading bacteria that biologically degrade organic matter. As the organic matter-degrading bacterium, an aerobic bacterium usually used for oxidative degradation of BOD or COD can be used. As an example, activated sludge from a sewage treatment plant can be used. When the raw water is sewage, the organic matter-degrading bacteria are contained as floating sludge in the raw water supplied to the treatment tank, so that activated sludge does not have to be added. Alternatively, activated sludge may be introduced into the treatment tank as a carrier encapsulated or adhered to the immobilization material. Furthermore, a fixed bed may be provided in the treatment tank, and activated sludge may be attached to the fixed bed as a biofilm. In addition, 1,4-dioxane degrading bacteria can also be used as the organic matter degrading bacteria.

  In the treatment apparatus 10B according to the third embodiment having the above-described configuration, a predetermined amount of raw water flows into the treatment tank. Then, the unreacted ozone gas and 1,4-dioxane waste gas generated in the accelerated oxidation treatment apparatus 20 are introduced into the aeration pipe 64 by the waste gas pump 28 as 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 state by aeration of the waste gas through the aeration pipe 64. Thereby, the organic matter in the raw water is oxidatively decomposed. At the same time, the waste gas containing ozone gas and 1,4-dioxane is aerated, so that 1,4-dioxane can be easily dissolved in the raw water because it is easily soluble in water. Moreover, when ozone gas is contained simultaneously, ozone gas can also be dissolved in raw | natural water and 1, 4- dioxane and ozone gas can be processed simultaneously. The ozone gas dissolved in the raw water is decomposed and removed by reacting organic substances in the wastewater. As ozone gas is decomposed, organic substances are also decomposed, so that the biological treatment efficiency can be increased. Moreover, if 1, 4- dioxane decomposing bacteria are used for organic substance decomposing bacteria, 1, 4- dioxane can be decomposed | disassembled within a processing tank.

  According to such a processing apparatus of the third embodiment, since 1,4-dioxane is made into an aqueous solution, it is not necessary to newly provide an apparatus such as a scrubber, and the cost of the entire apparatus can be reduced.

  FIG. 4 is a schematic configuration diagram of the apparatus for treating 1,4-dioxane in wastewater according to the fourth embodiment. The treatment apparatus 10 </ b> C of the fourth embodiment uses a biological treatment apparatus provided in the preceding stage of the storage tank 12 and the accelerated oxidation treatment apparatus 20 as means for forming an aqueous solution of 1,4-dioxane. The other configuration is the same as that of the processing apparatus 10 of the first embodiment, and the same reference numerals are given and detailed description is omitted.

  The biological treatment device 62 </ b> A is disposed in the front stage of the storage tank 12. Similar to the biological treatment device 62 of the third embodiment, the biological treatment device 62A includes an aeration tube 64A in the treatment tank. The aeration pipe 64A is connected to the exhaust pipe 26 of the accelerated oxidation processing apparatus 20. The treatment tank has organic matter-degrading bacteria that biologically degrade organic matter. As the organic matter-degrading bacterium, an aerobic bacterium usually used for oxidative degradation of BOD or COD can be used.

  In the treatment apparatus 10C of the fourth embodiment having the above-described configuration, a predetermined amount of raw water flows into the treatment tank of the biological treatment apparatus 62A. Then, the unreacted ozone gas and 1,4-dioxane waste gas generated in the accelerated oxidation treatment apparatus 20 are introduced into the aeration pipe 64A as air aeration gas by the waste gas pump 28. In the treatment tank, the organic matter decomposing bacteria and the raw water come into contact with each other under an aerobic state by air aeration of the waste gas through the aeration pipe 64A. Thereby, the organic matter in the raw water is oxidatively decomposed. At the same time, the waste gas containing ozone gas and 1,4-dioxane is aerated, so that 1,4-dioxane can be easily dissolved in the raw water because it is easily soluble in water. Moreover, when ozone gas is contained simultaneously, ozone gas can also be dissolved in raw | natural water and 1, 4- dioxane and ozone gas can be processed simultaneously. The ozone gas dissolved in the raw water reacts with organic substances in the wastewater and is decomposed and removed. As ozone gas is decomposed, organic substances are also decomposed, so that the biological treatment efficiency can be increased. The first treated water that has been biologically treated by the biodegradation treatment apparatus is introduced into the subsequent storage tank 12. In the biological treatment apparatus 62A, 1,4-dioxane dissolved in water cannot be decomposed by biological treatment using a normal organic matter-degrading bacterium. For this reason, most of 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the first treated water. And like 1st Embodiment, the decomposition process of 1, 4- dioxane is performed with the accelerated oxidation processing apparatus 20, and it discharge | emits out of the system as 2nd treated water. On the other hand, waste gas containing unreacted ozone gas and 1,4-dioxane generated in the treatment tank is used as air aeration gas for the biological treatment apparatus in the previous stage.

In addition, if a 1, 4- dioxane decomposing bacterium is used for an organic substance decomposing bacterium, 1, 4- dioxane can also be decomposed | disassembled within the processing tank of the biodegradation processing apparatus 62A.
According to such a processing method and apparatus of the fourth embodiment, 1,4-dioxane is made into an aqueous solution, so that it is not necessary to newly provide an apparatus such as a scrubber. By using a biological treatment tank on the same line as the accelerated oxidation process, the cost of the apparatus can be reduced.

  FIG. 5 is a schematic configuration diagram of the apparatus for treating 1,4-dioxane in wastewater according to the fifth embodiment. The treatment apparatus 10 </ b> D of the fifth embodiment uses a plurality of biological treatment apparatuses provided in the preceding stage of the storage tank 12 and the accelerated oxidation treatment apparatus 20 as the aqueous solution of 1,4-dioxane. The other configuration is the same as that of the processing apparatus 10 of the first embodiment, and the same reference numerals are given and detailed description is omitted. The biological treatment apparatus of the fifth embodiment is specifically composed of a first biological treatment apparatus 70 and a second biological treatment apparatus 72. In addition to this, three or more biological treatment tanks may be arranged according to the biological treatment process. Similar to the biological treatment apparatus of the third embodiment, the first biological treatment apparatus 70 includes an aeration pipe 64B in the treatment tank. The aeration pipe 64B is connected to the exhaust pipe 26 of the accelerated oxidation processing apparatus 20. The treatment tank has organic matter-degrading bacteria that biologically degrade organic matter. As the organic matter-degrading bacterium, an aerobic bacterium usually used for oxidative degradation of BOD or COD can be used. The second biological treatment apparatus 72 includes an aeration pipe 64C in the treatment tank, and a blower 65 is connected to the aeration pipe 64C so that air aeration gas can be supplied. The treatment tank has organic matter-degrading bacteria that biologically degrade organic matter. As the organic matter-degrading bacterium, an aerobic bacterium usually used for oxidative degradation of BOD or COD can be used.

  In the treatment apparatus 10D of the fifth embodiment having the above-described configuration, a predetermined amount of raw water flows into the treatment tank of the first biological treatment apparatus 70. Then, unreacted ozone gas and 1,4-dioxane waste gas generated in the accelerated oxidation treatment apparatus 20 are introduced into the aeration pipe 64B by the waste gas pump 28 as 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 state by air aeration of the waste gas through the aeration pipe 64B. At the same time, the waste gas containing ozone gas and 1,4-dioxane is aerated, so that 1,4-dioxane can be easily dissolved in the raw water because it is easily soluble in water. Moreover, when ozone gas is contained simultaneously, ozone gas can also be dissolved in raw | natural water. However, when the amount of ozone gas in the waste gas is large, the biological activity is lowered, and therefore, an environment in which biological treatment is difficult to proceed. Therefore, in the first biological treatment apparatus 70, the ozone concentration is mainly reduced by causing ozone gas to react with an organic substance or the like in the wastewater to decompose and remove it. And the 1st treated water processed with the 1st biological treatment apparatus 70 is introduced into the 2nd biological treatment apparatus 72 of a back | latter stage. In the second biological treatment device 72, since the ozone concentration is lower than that in the first biological treatment device 70, the biological activity is high. Therefore, the organic matter-decomposing bacteria and the first treated water come into contact with each other in an aerobic state by air aeration through the aeration tube 64C, and the organic matter in the first treated water is oxidatively decomposed.

  The second treated water biologically treated by the second biological treatment device 72 is introduced into the subsequent storage tank 12. In the first biological treatment apparatus 70, 1,4-dioxane dissolved in water cannot be decomposed by biological treatment using a normal organic matter-degrading bacterium. For this reason, most of 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the second treated water. And like 1st Embodiment, the decomposition process of 1, 4- dioxane is performed with the accelerated oxidation processing apparatus 20, and it discharge | emits out of the system as 3rd treated water. On the other hand, the waste gas containing unreacted ozone gas and 1,4-dioxane generated in the treatment tank is used as the air aeration gas for the first biological treatment apparatus 70 in the previous stage.

In addition, if a 1, 4- dioxane decomposing bacterium is used for the organic substance decomposing bacterium of the 2nd biological treatment apparatus 72, a 1, 4- dioxane can also be decomposed | disassembled within a processing tank.
According to the processing method and apparatus of the fifth embodiment as described above, there is a risk that the biological activity of the biological treatment tank may decrease when the waste gas contains a large amount of unreacted ozone gas. The ozone concentration can be changed between them, and a biological treatment environment suitable for biological treatment can be formed. Therefore, the influence which ozone gas has on organic matter-decomposing bacteria can be suppressed.

  FIG. 6 is a schematic configuration diagram of a treatment apparatus for 1,4-dioxane in wastewater according to the sixth embodiment. The treatment apparatus 10E of the sixth embodiment is the same as the treatment apparatus 10C of the fourth embodiment in the raw water treatment process, but as a 1,4-dioxane aqueous solution means, the scrubber of the treatment apparatus 10 of the first embodiment. A device 50 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 includes an aeration pipe 64C in the treatment tank, and a blower 65 is connected to the aeration pipe 64C so that air aeration gas can be supplied. The treatment tank has organic matter-degrading bacteria that biologically degrade organic matter. The 1,4-dioxane aqueous solution in the scrubber device 50 is introduced into the biological treatment device 62B.

  In the treatment apparatus of the sixth embodiment having the above configuration, a predetermined amount of raw water flows into the treatment tank of the biological treatment apparatus 62B. In the biological treatment device 62B, the organic matter-decomposing bacteria and the first treated water come into contact with each other in an aerobic state by air aeration through the aeration tube 64C, and the organic matter in the raw water is oxidized and decomposed. In addition, an aqueous solution of 1,4-dioxane generated in the scrubber device 50 is introduced into the biological treatment device 62B.

  The first treated water that has been biologically treated by the biological treatment device 62B is introduced into the subsequent storage tank 12. In the biological treatment apparatus 62B, 1,4-dioxane dissolved in water cannot be decomposed by biological treatment using a normal organic substance-degrading bacterium. For this reason, most of 1,4-dioxane is introduced into the storage tank 12 while being dissolved in the first treated water. And like 1st Embodiment, the decomposition process of 1, 4- dioxane is performed with the accelerated oxidation processing apparatus 20, and it discharges | emits out of the system as 2nd treated water. On the other hand, the waste gas containing unreacted ozone gas and 1,4-dioxane generated in the treatment tank is introduced into the scrubber device 50 from the upper part of the accelerated oxidation treatment device 20 by the waste gas pump 28 through the exhaust pipe 26. The

  In the scrubber device 50, the water supplied from the water supply pump 52 in the casing 51 is sprayed onto the lower filter medium 56 by the sprayer 54. Then, the unreacted ozone gas and 1,4-dioxane waste gas introduced from the accelerated oxidation treatment apparatus 20 are introduced into the casing 51 from below the filter medium 56. The waste gas flows upward by the suction force of the exhaust pump 58, comes into contact with the water sprayed through the filter medium 56, and is discharged from above. Since 1,4-dioxane is easily soluble in water, 1,4-dioxane contained in the waste gas is actively dissolved in the sprayed water to form an aqueous solution, that is, an aqueous solution of 1,4-dioxane. Become. The aqueous solution of 1,4-dioxane is introduced into the biological treatment apparatus 62B at the previous stage. Then, the accelerated oxidation treatment can be performed again by the accelerated oxidation treatment apparatus 20. On the other hand, 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, ozone gas that may corrode the piping can be separated and removed from 1,4-dioxane by a scrubber device. Therefore, since ozone gas is not introduced into the biological treatment apparatus, there is no risk of corrosion of the piping connected to the treatment tank, and deterioration of the entire apparatus over time can be prevented.

[Example 1]
The Example which processed the 1, 4- dioxane in wastewater with the processing apparatus 10 of 1st Embodiment is demonstrated below. In the accelerated oxidation treatment apparatus 20, a low-pressure mercury lamp with a lamp power of 48 W serving as the ultraviolet irradiation apparatus 40 was placed in a cylindrical treatment tank having an inner volume of 12 L. The irradiation amount 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 from the lower part of the treatment tank at a gas flow rate of 5 L / min. The residence time in the treatment tank was 2 hours, and the raw water was caused to flow into the treatment tank by the pump 14 from the lower introduction pipe 22.

  As the wastewater of this example, treated water obtained by biologically treating the wastewater from factory A was used. This wastewater contained 200 mg / L of 1,4-dioxane and 498 mg / L as a COD component, and also contained organic substances other than 1,4-dioxane.

  The 1,4-dioxane in the accelerated oxidation treated water is 8 mg / L to 12 mg / L, and 95% of 1,4-dioxane is removed by oxidative decomposition or diffusing, and about 5 of 1,4-dioxane inflowing. % Outflowed from the treated water. At this time, as a result of measuring the 1,4-dioxane concentration in the waste gas and calculating the amount of 1,4-dioxane to be diffused, it was found that about 8% of 1,4-dioxane was diffused. . In addition, 15% of the ozone gas that flowed in was unreacted and contained in the waste gas.

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

  For these reasons, in the conventional accelerated oxidation treatment apparatus, about 8% of 1,4-dioxane is diffused and released into the atmosphere, but by using the treatment apparatus 10 of this embodiment, gas is released together with ozone gas. It was found that the amount of 1,4-dioxane that is scattered and released out of the system can be greatly reduced.

The material balance of the accelerated oxidation treatment apparatus is as follows.
In the conventional accelerated oxidation treatment apparatus, the treated water was 5 and the air diffusion was 8 with respect to the raw water 100. In the treatment apparatus of this embodiment, the treated water was 5 and the air scatter was 0.8 relative to the raw water 100.
Note that the concentration of ozone gas in the processing gas after the scrubber treatment was reduced to about ３ compared with that before the treatment, and it was possible to reduce the burden on the waste ozone gas treatment.

[Example 2]
The Example which processed the 1, 4- dioxane in waste water with the processing apparatus of 3rd Embodiment is demonstrated 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 in a residence time of 24 hours. In the reaction tank, a plastic contact material for maintaining a living thing is put.

  The operating conditions of the raw water and the accelerated oxidation treatment apparatus are the same as those in Example 1, and only the waste gas treatment method is different. The waste gas was connected to a line for supplying air aeration gas (air, oxygen) to the biological treatment device 62, and waste gas containing ozone gas and 1,4-dioxane was supplied. As a result, the 1,4-dioxane concentration discharged from the biological treatment device 62 by air diffusing could not be detected, and the air scatter could be prevented. Moreover, the waste ozone gas could be processed to 0.1 mg / L or less, and therefore an apparatus for treating the waste ozone gas became unnecessary.

[Example 3]
An example in which 1,4-dioxane in wastewater is treated with the treatment apparatus of the fifth embodiment will be described below. The COD of factory A wastewater is 2010 mg / L, and can be treated up to 498 mg / L by biological treatment with the first biological treatment apparatus 70, and the 1,4-dioxane concentration was 200 mg / L (the biological organism of Example 1). Same as treated water). Waste ozone gas could also be processed to 0.1 mg / L or less. For this reason, the apparatus for processing waste ozone gas became unnecessary.

  In the second biological treatment apparatus 72, since air scatter was originally caused by aeration, unlike the case of Example 2, the air scatter of 1,4-dioxane was confirmed. There was almost no increase in airflow. From these things, it has confirmed that it was effective in the process of 1, 4- dioxane diffused with the accelerated oxidation processing apparatus, and the process of waste ozone gas.

10, 10A, 10B, 10C, 10D, 10E ......... Processing device for 1,4-dioxane in wastewater, 12 ......... Storage tank, 14 ...... Pump, 20 ...... Accelerated oxidation processing device, 22 ... ...... Introducing pipe, 24 ....... outlet pipe, 26 .... exhaust pipe, 28 .... waste gas pump, 30 .... ozone treatment device, 32 .... ozone generator, 34 .... ozone gas injection pipe, 36 ......... Air diffuser, 40 ......... UV irradiation device, 50 ......... Scrubber device, 51 ......... casing, 52 ......... feed pump, 53 ......... waste water tube, 54 ...... sprayer, 56 ... ... Filter medium, 58 ... Exhaust pump, 59 ... ... Ozone waste gas pipe, 60 ... ... Ozone treatment equipment, 62, 62A ... ... Biological treatment equipment, 64, 64A, 64B, 64C ... ... Aeration pipe , 65 ......... Blower, 70 ......... First biological treatment device 72 ......... second biological treatment device.

Claims (8)

The 1,4- diffused together with ozone gas generated in the accelerated oxidation process for decomposing 1,4-dioxane contained in waste water by using one or more of ozone treatment and hydrogen peroxide treatment or ultraviolet treatment. Dissolving waste gas containing dioxane in water to make the 1,4-dioxane into an aqueous solution ,
The aqueous solution is formed by spraying the waste gas flow path in the casing with the sprayer with a scrubber provided with the water sprayer in the casing to bring the waste gas and water into gas-liquid contact. A method for treating 1,4-dioxane in wastewater. The method for treating 1,4-dioxane in wastewater according to claim 1 , wherein the water supplied to the scrubber uses treated water treated in the accelerated oxidation step. The 1,4- diffused together with ozone gas generated in the accelerated oxidation process for decomposing 1,4-dioxane contained in waste water by using one or more of ozone treatment and hydrogen peroxide treatment or ultraviolet treatment. Dissolving waste gas containing dioxane in water to make the 1,4-dioxane into an aqueous solution,
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 aeration gas in a biological treatment process separate from the treatment line including the accelerated oxidation process. A method for treating 1,4-dioxane in wastewater. The treatment of 1,4-dioxane in wastewater according to claim 1 or 2 , wherein the 1,4-dioxane discharged from the scrubber is introduced into a biological treatment step preceding the accelerated oxidation step. Method. Accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater using ultraviolet rays, hydrogen peroxide solution, any one or more of alkaline solutions, and ozone gas;
A means for forming an aqueous solution of 1,4-dioxane, wherein the waste gas containing 1,4-dioxane dispersed together with the ozone gas generated in the accelerated oxidation step of the accelerated oxidation means is brought into contact with water;
Equipped with a,
The aqueous solution of 1,4-dioxane includes the water sprayer in a casing, and water is sprayed to the waste gas flow path in the casing by the sprayer to bring the waste gas and water into gas-liquid contact. An apparatus for treating 1,4-dioxane in wastewater, characterized by being a scrubber to be used. The apparatus for treating 1,4-dioxane in wastewater according to claim 5 , wherein the water supplied to the scrubber is treated water treated by the accelerated oxidation means. Accelerated oxidation means for decomposing 1,4-dioxane contained in wastewater using ultraviolet rays, hydrogen peroxide solution, any one or more of alkaline solutions, and ozone gas;
A means for forming an aqueous solution of 1,4-dioxane, wherein the waste gas containing 1,4-dioxane dispersed together with the ozone gas generated in the accelerated oxidation step of the accelerated oxidation means is brought into contact with water;
The 1,4-dioxane aqueous solution means is a biological treatment means that uses the waste gas as an aeration gas to a biological treatment tank separate from the treatment line including the accelerated oxidation means. 4-dioxane processing apparatus. The treatment of 1,4-dioxane in waste water according to claim 5 or 6 , wherein the 1,4-dioxane discharged from the scrubber is introduced into a biological treatment means upstream of the accelerated oxidation means. apparatus.