JP2001137837A - Treating device for water containing volatile organic material, and non-polluting treating device for groundwater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating device for water which is capable of cost effectively and efficiently subjecting the volatile organic materials in water to a non-polluting treatment. SOLUTION: The water containing the volatile organic materials is treated by a means for migrating the volatile organic material in the water to a gaseous phase, such as a membrane deaeration means 10, by which the water is subjected to the separation of gas from the liquid to the gas containing the volatile organic material and the water removed of the volatile organic material. The gas containing the volatile organic material is transferred to an atmospheric pressure low-temperature plasma device like an atmospheric pressure low- temperature microwave device 20 and is subjected to a cracking treatment by the plasma in this device 20, by which the gas is made non-polluting. The water removed of the volatile organic material is discharged as treated water from the means 10, by which the non-polluting treatment of the water containing the volatile organic material is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating water containing volatile organic substances, and more particularly to an apparatus utilizing a low-pressure plasma apparatus under normal pressure. In addition, the present invention relates to a detoxification apparatus for groundwater that applies the above-described processing apparatus and detoxifies organic halogenated substances contained in groundwater using a normal-pressure low-temperature plasma apparatus.

[0002]

2. Description of the Related Art In recent years, with the increase in the concentration of organic substances in river water, a large amount of chlorine for sterilization or purification has tended to be used, and carcinogenic substances or mutagens generated by the reaction of these organic substances with chlorine. There is a problem that the concentration of trihalomethane, which is a toxic substance, is increased, and the trihalomethane is slightly dissolved in tap water.

In various industries such as the machinery industry, the electronics industry, and the cleaning industry, trichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, carbon tetrachloride, 1,1,1,1-trichloroethane used for the purpose of degreasing and cleaning.
It is also a problem that factory effluents containing organic halogenated substances such as 2-trichloroethane and 1,2-dichloroethane and volatile organic substances such as benzene permeate underground and contaminate groundwater. Groundwater has special characteristics such as extremely slow flow velocity and no dilution / diffusion.It is difficult to recover once it is contaminated. The demand is great. Further, a technique for purifying not only groundwater but also river water, lake water and the like contaminated by volatile organic substances including these organic halogenated substances is desired. Furthermore, it is very dangerous that even small amounts of these organic halogenated substances are present in industrial water for food and medicine, and the industry in this field removes trace organic halogenated substances dissolved in water. Technology is long-awaited.

Conventionally, various methods have been known for treating volatile organic substances dissolved in water. Japanese Patent Application Laid-Open No. 9-276850 discloses that wastewater containing a volatile organic substance is introduced into a packed aeration tower for treatment, the volatile organic substance dissolved in water is transferred to a gas phase, and the solvent is circulated through the gas. A solvent extraction method in which a volatile organic substance is absorbed into a solvent by introducing the solvent into an absorption tower is disclosed. Also, Japanese Patent Application Laid-Open No. 6-47
No. 370 discloses a method in which drainage in which a volatile organic substance is dissolved is flowed into the hollow portion of a hollow fiber membrane to exhaust the membrane surface, or a wastewater in which a volatile organic substance is dissolved is flown to the outer surface of the hollow fiber membrane to form a hollow fiber. An apparatus is disclosed in which a volatile organic substance is transferred to a gas phase by exhausting a hollow portion of a yarn membrane and a gas containing the volatile organic substance is adsorbed by an adsorbent such as activated carbon to perform an adsorption treatment. Further, Japanese Patent Application Laid-Open No. 7-308660 discloses that an organochlorine compound in groundwater is treated in an aeration tank, the organochlorine compound in the water is transferred to a gaseous phase, and the obtained gas is heated to contain a reaction containing a solid catalyst. A groundwater purification treatment facility is disclosed which is supplied to a tank and used in a catalytic decomposition method for thermally decomposing an organic chlorine compound. In addition, the actual opening 4-701
No. 26 discloses an ultraviolet ray decomposition method of decomposing a volatile organic chlorine compound by irradiating a volatile organic substance in a gas discharged by aerating a wastewater containing the volatile organic chlorine compound with ultraviolet rays. I have.

[0005]

However, in the above-mentioned conventional methods, the following problems exist in the treatment after the volatile organic substance in the water is transferred to the gas phase. The solvent extraction method only separates the volatile organic substances, and this method cannot decompose the volatile organic substances.Therefore, it is necessary to perform a separate treatment such as incineration of the solvent containing the separated volatile organic substances. Requires effort. In addition, the adsorption treatment method of adsorbing volatile organic substances on activated carbon or the like does not decompose the volatile organic substances but merely separates them.Finally, the volatile organic substances adsorbed on the activated carbon are subjected to heat treatment or the like. Further equipment is required to separate volatile organic substances by desorbing them from activated carbon, and to separately treat the collected volatile organic substances to be harmless. In addition, deterioration of the performance of the adsorbent due to long-term use is unavoidable, and it becomes necessary to exchange and regenerate the adsorbent at regular intervals, which is costly and complicated. In addition, in the catalytic decomposition method, the decomposition efficiency of volatile organic substances under low concentration conditions is poor, and the concentration of volatile organic substances in the gas can be reduced only by transferring the volatile organic substances from the water to the gas phase by aeration treatment. , The concentration means may be required. In addition, since the catalytic reaction is inhibited by the coexisting substance, a means for pretreating the gas before the reaction may be required in some cases. Furthermore, since the catalytic reaction tower itself is relatively large, the installation area of the entire apparatus from the gas phase transfer to the decomposition reaction is large. Further, the UV decomposition method also has a problem of poor decomposition efficiency.

The present invention has been made in view of such circumstances, and a water treatment apparatus containing a volatile organic substance according to the first aspect of the present invention is capable of economically and efficiently processing a volatile organic substance in water. It is an object of the present invention to efficiently perform detoxification processing, and a water treatment apparatus containing a volatile organic substance according to the invention of claim 2 is capable of detoxifying volatile organic substances in water more economically and efficiently. The treatment apparatus for water containing a volatile organic substance according to the third aspect of the present invention is intended to be capable of treating the volatile organic substance in water so as to be able to detoxify the volatile organic substance in water even more economically and efficiently. The purpose is to. Further, the detoxification apparatus for groundwater containing an organic halogenated substance according to the invention according to claim 4 aims to economically and efficiently detoxify an organic halogenated substance in groundwater, and The detoxification apparatus for groundwater containing an organic halogenated substance according to the fifth aspect of the present invention is capable of economically and efficiently detoxifying an organic halogenated substance in groundwater, and is capable of detoxifying an organic halogenated substance by hydrogen halide generated during the treatment. The detoxification apparatus for groundwater containing an organic halogenated substance according to the invention according to claim 6 is intended to prevent secondary pollution, and the detoxification processing apparatus according to the invention according to claims 4 and 5 It is intended to be able to more economically and efficiently.

[0007]

According to the present invention, there is provided a means for transferring a volatile organic substance from water containing a volatile organic substance to a gaseous phase, and a volatile organic substance in a gas obtained by the means. And a normal-pressure low-temperature plasma device for decomposing water. According to a second aspect of the present invention, there is provided the water treatment apparatus according to the first aspect, wherein the means for transferring the volatile organic substance from water containing the volatile organic substance to the gaseous phase is an aeration means or a film deaeration. There is provided an apparatus for treating water containing volatile organic substances, the apparatus comprising means. According to a third aspect of the present invention, there is provided the water treatment apparatus according to the first or second aspect, wherein the normal-pressure low-temperature plasma apparatus is a normal-pressure low-temperature microwave plasma apparatus or a normal-pressure low-temperature discharge plasma apparatus. An apparatus for treating water containing volatile organic substances is provided.
According to the present invention, a well buried in soil containing groundwater containing an organic halide, a pump for sucking groundwater containing an organic halide through the well, and suction by the pump An aeration tank for transferring the organic halide substance from the groundwater containing the organic halide substance to the gas phase, and a normal-pressure low-temperature plasma apparatus for decomposing the organic halide substance in the gas generated from the aeration tank. Provided is a detoxification treatment device for groundwater containing a characteristic organic halogenated substance. According to a fifth aspect of the present invention, there is provided the detoxification apparatus for groundwater according to the fourth aspect, further comprising means for contacting the exhaust gas after the treatment with the normal-pressure low-temperature plasma apparatus with an alkali solution. To provide a detoxification apparatus for groundwater containing organic halogenated substances. According to a sixth aspect of the present invention, there is provided the detoxification apparatus for groundwater according to the fourth or fifth aspect, wherein the normal-pressure low-temperature plasma apparatus is a normal-pressure low-temperature microwave plasma apparatus or a normal-pressure low-temperature discharge plasma apparatus. The present invention provides a detoxification apparatus for groundwater containing an organic halogenated substance.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The volatile organic substances in the present invention include, but are not limited to, the following, including organic halogenated substances and odorous substances. (Hydrocarbons) benzene, toluene, xylene, methane, ethane, butane, hexane, cyclohexane, hexene; (alcohols) isopropyl alcohol, methanol; (ketones) acetone, methyl ethyl ketone; (organic acids) formic acid, acetic acid; (aldehyde (Formers) formaldehyde, acetaldehyde; (esters) ethyl acetate, butyl acetate; (organic halogenated substances) trichloroethylene, 1,
1,1-trichloroethane, tetrachloroethylene, carbon tetrachloride, 1,1,2-trichloroethane, 1,2-dichloroethane, Freon-12 (CFC-12), Freon-113 (CFC-113), methyl bromide; Substances) dimethyl sulfide, mercaptan, ammonia;

The water in the present invention may be water of any origin, and includes, for example, tap water, industrial water, groundwater, well water, river water, lake water, sewage, industrial wastewater, and the like. . In addition, groundwater refers to water existing in the aquifer below the underground soil.

Next, FIG. 1 shows a flow sheet of an apparatus for treating water containing a volatile organic substance according to an embodiment of the present invention, which will be described below. In the embodiment shown in FIG. 1, a film degassing means 10 is used as a means for transferring a volatile organic substance in water to a gas phase, and a normal-pressure low-temperature microwave plasma device 20 is used as a normal-pressure low-temperature plasma device. In the membrane deaerator 10, the volatile organic substance in the water is transferred to the gas phase, and is separated into a gas containing the volatile organic substance and water from which the volatile organic substance has been removed. The water from which the volatile substances have been removed is discharged from the membrane deaerator 10 as treated water. The treated water can be used for any purpose if possible, and is used for industrial water such as cooling water and washing water or agricultural water, and also used for drinking water after disinfection. it can. As means for transferring volatile organic substances in water to the gaseous phase, in addition to the membrane deaerator 10, an aeration unit or a boiling unit can be applied, but a process such as heating is not required and the viewpoint is simple. Therefore, aeration means or membrane deaeration means is preferred. Here, examples of the apparatus provided with the aeration means include, but are not limited to, an aeration treatment tank as shown in FIG.

A container 11 of the membrane deaerator 10 shown in FIG. 1 is a container having an air inlet 12 for sucking in outside air and an outlet 13 for a gas containing volatile organic substances and water vapor.
A large number of hollow fiber membranes 14 are arranged in the inside 1 at predetermined intervals so that both ends thereof are supported and fixed by a potting agent 15. Further, at one end of the container 11, the hollow fiber membrane 1 supported and fixed by the potting agent 15 is provided.
An inlet 16 for water containing a volatile organic substance is provided which communicates with a space formed by the inner wall of the container 4 and the inner wall of the container 11. An outlet 17 is provided. By the potting agent 15, a partition wall that blocks a space formed between the plurality of hollow fiber membranes 14, 14,..., And the inlet 16 and the outlet 17 of the water containing the volatile organic substance is formed. It is formed. Further, an exhaust port 13 is provided on a part of the peripheral surface of the container 11, and a decompressor (intake blower) 1 is provided in the middle of the exhaust port 13.
8 are installed. When the gas in the container 11 is sucked by the decompressor 18, external air is taken into the container 11 from an air inlet 12 provided in the container 11, and further, volatile organic substances flowing inside the hollow fiber membrane 14. The volatile organic substance is transferred from the water containing to the gas phase through the hollow fiber membrane 14. With this configuration, the gas containing the volatile organic substance is discharged from the exhaust port 13 provided in the container 11.

The hollow fiber membrane 14 has a pore diameter of 0.05 μm.
m or less can be used, but if used for a long time, water vapor leaks, and as a result, water may leak from the porous membrane.
A multilayer composite hollow fiber membrane comprising a homogeneous membrane having the following film thickness and a porous membrane having a reinforcing function, wherein a homogeneous membrane and a porous membrane are alternately laminated, and a side of the multilayer composite hollow fiber membrane which comes into contact with an aqueous solution. Is a homogeneous membrane or a porous membrane, the layer not in contact with the aqueous solution is a porous membrane, and the composite hollow fiber membrane has a chloroform permeation rate of 1 × 10 ⁻³ (c
It is preferable that the hollow fiber membrane has a permeability of at least m ³ (STP) / cm ² / sec / cmHg. Chloroform transmission rate is 1 × 10 ⁻³ (cm ³ (STP) / c
If the pressure is less than m ² / sec / cmHg), the permeation rate of the volatile organic substance contained in water through the composite membrane is low, and the volatile organic substance cannot be efficiently transferred to the gas phase.

Materials for forming the porous layer of such a composite membrane include polyethylene, polypropylene, poly-3-
Polyolefins such as methylbutene-1, poly-4-methylpentene-1 and the like, vinylidene fluoride, fluorinated polymers such as polytetrafluoroethylene, and polymers such as polysulfone, polyetherketone, and polyetheretherketone can be used. Is preferably a polyolefin which is a crystalline polymer capable of easily forming a porous material. Materials used for the homogeneous layer of the composite film include segmented polyurethane, silicon-based polymer, low-density polyethylene, and poly-4-methylpentene-1.
And polyacrylamide, etc., and a polymer having high affinity for volatile organic substances is preferable.

The means for transferring the volatile organic substance in the water into the gas phase is connected to the low-pressure plasma apparatus at normal pressure, and the gas containing the volatile organic substance discharged from the exhaust port 13 is supplied to the low-temperature plasma apparatus at normal pressure. Be transported. In a normal-pressure low-temperature plasma device, volatile organic substances in the transferred gas react with plasma generated by the device to be decomposed, and the gas after the decomposition reaction is discharged from the normal-pressure low-temperature plasma device. The normal-pressure low-temperature plasma device is a plasma device that generates plasma in which only the electron temperature is extremely high under normal pressure, as long as it can decompose volatile organic substances, and is preferably An ordinary-pressure low-temperature microwave plasma apparatus or an ordinary-pressure low-temperature discharge plasma apparatus can be used, and FIG. 1 shows an ordinary-pressure low-temperature microwave plasma apparatus 20.

Normal pressure low-temperature microwave plasma apparatus 2 shown in FIG.
0 has a microwave source 21 which is connected by a waveguide 22 to a microwave cavity 23 in which a container 24 is placed. When the microwave source 21 is turned on, a microwave field is generated in the microwave cavity 23, and a microwave field is also generated in the container 24 installed therein. The container 24 is provided with a gas inlet 27, and a gas containing the volatile organic substance discharged from the exhaust port 13 of the means for transferring the volatile organic substance in the water to the gas phase passes through the gas inlet 27 into the container 24. And becomes fuel of the plasma 26. The microwave power typically required to generate the plasma 26 is 0.3-5 kW. In view of the high temperature of the plasma 26 in the container 24, the container wall is made of a heat-resistant material such as quartz.

The container 24 is also provided with an ignition port 28, and an electrode 29 is inserted through the ignition port 28 when generating plasma. The presence of the electrode 29 in the container 24 increases the intensity of the microwave field at a portion adjacent to the tip of the electrode 29, and discharge starts when the intensity of the microwave field in this region becomes sufficiently large. As a result, the gas around the electrode 29 is ionized, and the plasma 26 is formed and floats on the upper part in the container 24. After the plasma 26 is generated in the container 24, the electrode 29 is pulled out of the container 24. The electrode 29 is an elongated member having a pointed tip, and may be made of a conductive material. From the viewpoint of not affecting the microwave field, the electrode material is preferably carbon fiber. The size of the plasma 26 in the container 24 is adjusted by changing the output level of the microwave source 21. An exhaust port 25 is provided at a lower portion of the container 24, and a gas after the volatile organic substance has reacted with the plasma is exhausted from the exhaust port 25.

FIG. 2 shows another embodiment of a normal-pressure low-temperature plasma apparatus that can be used in the water treatment apparatus of the present invention.
It is a longitudinal cross-sectional view of a normal-pressure low-temperature discharge plasma device. The cylindrical normal-pressure low-temperature discharge plasma apparatus shown in FIG. 2 is of a packed-bed discharge type, has an internal electrode 31 and an external electrode 32, and is located in a plasma processing chamber 39 between the two electrodes. The porous adsorbent 33 and the granular ferroelectric substance 34 are physically mixed and filled. Internal electrode 31 and external electrode 3
During the period 2, a high voltage is applied by the power supply 35. At both ends of the plasma processing chamber 39, a Teflon cap 36 and a holding plate 37 are provided. The apparatus also has a gas inlet 38 through which gas containing volatile organic substances is introduced. The introduced gas containing the volatile organic substance is mixed with the porous adsorbent 33 into the ferroelectric substance 34 through the through-hole of the Teflon pressing plate 37 at one end in the flow path indicated by the arrow a to fill the plasma. After being introduced into the processing chamber 39 and the volatile organic substance is decomposed by the plasma, the gas after the processing is exhausted from the exhaust port 40 as a flow indicated by an arrow b from the through hole of the holding plate 37 at the other end. .

As the porous adsorbent 33, a non-conductive substance is used from the viewpoint of generating plasma, and an inorganic porous substance is preferable. For example, Al ₂ O ₃ , Si
O ₂ , zeolite (A type, X type, Y type, etc.), TiO ₂
And the like. The ferroelectric substance 34 and the porous adsorbent 33 are preferably in a granular form so that a gas passage can be formed in the packed bed. As for the size of the granule, the diameter of the bottom surface of the cylindrical body, the ellipse or the spherical body is 1 to 3 mm, and more preferably 1 to 2 mm. The voltage applied between the internal electrode 31 and the external electrode 32 by the power supply 35 changes depending on the concentration of the volatile organic substance in the gas to be processed,
Usually 1 to 10 kV / cm, preferably 1 to 5 kV / cm
It is.

FIG. 2 shows an ordinary-pressure low-temperature discharge plasma apparatus.
In addition to those shown in, for example, surface discharge, barrier discharge,
Examples include, but are not limited to, a plasma device using a discharge method such as pulse discharge or capillary tube discharge.

FIG. 3 shows a flow sheet of a detoxification apparatus for groundwater containing an organic halogenated substance according to another embodiment of the present invention, which will be described below. The detoxification apparatus for groundwater containing an organic halogenated substance according to the present invention has a well 41 excavated so as to reach an aquifer having groundwater contaminated with an organic halogenated substance such as trichlorethylene. In the groundwater detoxification apparatus according to the present invention, the wells 41 can be excavated and used in a required number according to the amount of groundwater to be collected and the area. In order to collect groundwater containing an organic halogenated substance from the well 41, a pump 42 as a pump for pumping groundwater is installed. The groundwater pumped by the pump 42 is transferred to an aeration tank 43 which is a means for transferring the organic halogenated substance in the water to the gas phase. In FIG. 3, the pump is installed on the ground and pumps water through pipes. However, the pump is not limited to the type installed on the ground, and is a type that is pumped into groundwater of a well to pump groundwater. Various pumps, such as the above pump, can be used.

A pipe 44 for introducing contaminated water is installed in the upper part of the aeration tank 43, and groundwater containing an organic halogenated substance transferred from the pump 42 is aerated through the pipe 44. It is put into the upper part of the processing tank 43. The aeration tank 43 is filled with a filler 45 such as Raschig ring or teralet packing, and a drainage pipe 46 for treated water and a blower 47 for suction are connected to the lower part of the aeration tank to aerate contaminated groundwater. The organic halide material is converted into a gaseous phase by the treatment, and gas-liquid separation is performed between a gas containing the organic halide material and groundwater from which the organic halide material has been removed. The treated water after the organic halogenated substance is separated by aeration treatment is discharged from the drain pipe 46, and is used for industrial water such as cooling water, washing water or agricultural water, and is also disinfected and sterilized into drinking water. Is also used. In places where there is a risk of land subsidence, it may be returned underground.

A pipe 48 for discharging a gas containing an organic halogenated substance is provided above the aeration tank 43, and the pipe 48 is connected to the gas inlet 2 of the normal-pressure low-temperature plasma apparatus.
The gas containing the organic halogenated substance which has been transferred to the gas phase in the aeration tank 43 is connected to the pipe 48.
Is transferred to the normal pressure low temperature plasma apparatus through The organic halogenated substance introduced into the atmospheric pressure low-temperature plasma apparatus is decomposed by reacting with the plasma, and the decomposed gas is supplied to the exhaust port 2 of the container.
5 is exhausted. The normal-pressure low-temperature plasma apparatus constituting the detoxification apparatus for groundwater of the present invention is a plasma apparatus that generates plasma in which only the electron temperature is extremely high under normal pressure, and decomposes organic halogenated substances. Any normal pressure low-temperature microwave plasma apparatus shown in FIG. 3 may be used, as well as a normal pressure low-temperature discharge plasma apparatus as shown in FIG.

As another embodiment of the detoxification apparatus for groundwater containing an organic halogenated substance according to the present invention, a means for contacting an exhaust gas treated by an ordinary-pressure low-temperature plasma apparatus with an alkali liquid after an ordinary-pressure low-temperature plasma apparatus. Can be connected. With this configuration, when an organic halogenated substance is decomposed in a normal-pressure low-temperature plasma apparatus, an acid gas of hydrogen halides such as hydrogen chloride produced as a by-product is absorbed in the alkaline liquid, and the gas is treated in the exhaust gas after the treatment. It is possible to prevent secondary contamination due to the contained harmful acidic gas. As a means for bringing the exhaust gas into contact with the alkaline liquid, any means can be used as long as the hydrogen halide gas by-produced in the normal-pressure low-temperature plasma apparatus can be brought into contact with the alkaline liquid to neutralize the exhaust gas. For example, an alkali scrubber having a means for spraying and supplying an aqueous alkali solution to a treated exhaust gas containing hydrogen halides to make gas-liquid contact, or a special porous plate having an extremely fine air passage hole may be used. A packed tower or the like having a means for passing the treated exhaust gas containing hydrogen hydride to form fine bubbles and contact the alkaline solution on the porous plate is exemplified. Means for bringing the exhaust gas into contact with the alkaline liquid include economy,
From the viewpoint of efficiency, an alkaline scrubber 50 as shown in FIG. 3 is preferable.

The alkaline scrubber 50 has a lower water tank 54 of a packed tower 53 filled with a contact material 52 such as Raschig ring or teralet packing, and a spray nozzle 55 provided above the contact material 52 with a circulation pump 56 interposed therebetween. The lower water tank 54 is connected via a circulation pipe, and is connected to a storage tank 58 for an alkaline solution having a relatively high concentration and a supply pipe 59 via a supply pump 57. The circulation pipe is provided with a pH meter for measuring the pH of the alkaline aqueous solution, and the supply pump 57 is controlled to be on-off so that the pH of the alkaline aqueous solution measured by the pH meter is maintained at a constant value. Can be configured. Further, a gas inlet 51 for introducing a gas containing hydrogen halide exhausted from the normal-pressure low-temperature plasma apparatus into the tower is provided at a lower part of the packed tower 53, and a gas inlet 51 is provided at an upper part of the packed tower 53 after treatment. An exhaust port 60 for exhausting the gas is provided. With this configuration, the acidic gas of hydrogen halides generated by the decomposition of the organic halogenated substance in the normal-pressure low-temperature plasma apparatus is supplied from the gas inlet 51 into the packed tower 53, so that the liquid spray nozzle of the packed tower 53 It comes into contact with the aqueous alkali solution that has been sprinkled from 55. As a result, the acidic gas component is absorbed and removed in the alkaline aqueous solution, and the treated gas is exhausted from the exhaust port 60.

As the alkaline liquid used in the means for bringing the exhaust gas into contact with the aqueous alkaline solution, any alkaline liquid can be used as long as it can neutralize hydrogen halides, but from the viewpoint of economy and easy handling. From
An aqueous sodium hydroxide solution or an aqueous sodium carbonate solution is preferred. As the alkaline solution, any pH solution can be used as long as it is alkaline. However, the pH is 8.0 in consideration of the durability of the apparatus, the neutralization efficiency, the ease of handling, and the like.
The range of ~ 12.0 is preferred.

[0026]

As described above, according to the water treatment apparatus containing a volatile organic substance according to the first to third aspects of the present invention, the volatile organic substance contained in the water is transferred to the gas phase. Since the volatile organic substance in the generated gas is decomposed by the low-pressure plasma apparatus at normal pressure, it is possible to not only isolate the volatile organic substance present in the water but also directly decompose it. In addition, even if the volatile organic substance contained in the water has a low concentration, it can be efficiently decomposed at low cost because an operation such as concentration is unnecessary. Furthermore, it is advantageous in terms of equipment and space as compared with the treatment of volatile organic substances by conventional means.

According to the apparatus for detoxifying groundwater containing an organic halogenated substance of the invention according to claims 4 and 6, the groundwater containing an organic halogenated substance is pumped and treated in an aeration tank. The organic halogenated substances are transferred to the gas phase, and the organic halogenated substances in the gas are decomposed by the low-pressure plasma apparatus at normal pressure. Becomes possible. Further, even if the organic halogenated substance contained in the groundwater has a low concentration, it can be efficiently decomposed at low cost because an operation such as concentration is unnecessary. Further, it is advantageous in terms of equipment and space as compared with the treatment of organic halogenated substances by conventional means.

According to the detoxification apparatus for groundwater containing an organic halogenated substance according to the fifth and sixth aspects of the present invention, groundwater containing an organic halogenated substance is pumped and treated in an aeration tank. Since the organic halide substance is transferred to the gaseous phase, the organic halide substance in the gas is decomposed by a normal-pressure low-temperature plasma apparatus, and further, a means for neutralizing and removing hydrogen halide generated by the decomposition processing is provided. In addition to the effects of the device of the invention according to claim 4, it is possible to prevent secondary contamination by hydrogen halide as an acidic substance,
As a whole, the organic halogenated substance can be economically and efficiently detoxified.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing one embodiment of a water treatment apparatus according to the present invention.

FIG. 2 is an embodiment of a normal-pressure low-temperature discharge plasma processing apparatus that can be used in the water processing apparatus according to the present invention.

FIG. 3 is a flow sheet showing one embodiment of a detoxification apparatus for groundwater according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Membrane deaeration means 20 Normal pressure low-temperature microwave plasma apparatus 41 Well 42 Pumping pump 43 Aeration tank 50 Alkaline scrubber

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C02F 1/58 B01D 53/34 134E F-term (Reference) 4D002 AA21 AC10 BA02 BA05 BA09 CA07 CA11 DA02 DA12 DA16 EA02 GA03 GB09 4D011 AA15 AA17 AB01 AD03 4D037 AA01 AB14 BA23 BB05 CA03 CA12 CA14 4D038 AA02 AB14 BA02 BA04 BB03 BB07 BB09 BB13 BB16

Claims (6)

[Claims] 1. A means for transferring a volatile organic substance from water containing a volatile organic substance to a gaseous phase, and a normal-pressure low-temperature plasma apparatus for decomposing a volatile organic substance in a gas obtained by the means. An apparatus for treating water containing volatile organic substances. 2. The water treatment apparatus according to claim 1, wherein the means for transferring the volatile organic substance from water containing the volatile organic substance to the gas phase comprises aeration means or film deaeration means. Water treatment apparatus containing volatile organic substances. 3. The water treatment apparatus according to claim 1, wherein the normal-pressure low-temperature plasma apparatus is a normal-pressure low-temperature microwave plasma apparatus or a normal-pressure low-temperature discharge plasma apparatus. Including water treatment equipment. 4. A well buried in soil containing groundwater containing an organic halide, a pump for sucking groundwater containing the organic halide through the well, and an organic halide sucked by the pump. Organic halogen, comprising: an aeration tank for transferring an organic halide substance from a groundwater containing gas into a gaseous phase; and a normal-pressure low-temperature plasma apparatus for decomposing an organic halide substance in a gas generated from the aeration tank. Detoxification equipment for groundwater containing chemical substances. 5. The apparatus for detoxifying underground water according to claim 4, further comprising means for contacting the exhaust gas after the treatment with a normal-pressure low-temperature plasma apparatus with an alkali solution. Detoxification equipment for underground water. 6. The organic halogenation treatment apparatus according to claim 4, wherein the atmospheric pressure low-temperature plasma apparatus is an ordinary pressure low-temperature microwave plasma apparatus or an ordinary pressure low-temperature discharge plasma apparatus. Detoxification equipment for groundwater containing substances.