JP2001113262A - Method, apparatus and system for treating organic chlorine compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove organic chlorine compounds from every kind of polluted soil surely in a short period without affecting treated soil. SOLUTION: An apparatus 1 for treating organic chlorine compounds is constituted of a storage tank 2 for storing polluted water 5 as a polluted medium containing the organic chlorine compounds, a pair of an anode 3a and cathode 3b arranged in the storage tank 2, and a power source 4 connected with the anode 3a and the cathode 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method, apparatus and system for detoxifying an organic chlorine compound such as trichloroethylene.

[0002]

2. Description of the Related Art Soil in a factory site may contain organochlorine compounds such as trichloroethylene and tetrachloroethylene which are carcinogenic substances. Chlorine compounds may diffuse into the environment. Therefore, a predetermined purification treatment must be performed on such contaminated soil.

On the other hand, recently, a technique for decomposing and detoxifying pollutants in the environment by utilizing the activity of microorganisms, that is, research on bioremediation has been advanced, and application to contaminated soil as described above has also been studied. It has become.

[0004]

The method of treating contaminants using such microorganisms has been confirmed to have achieved satisfactory results at least at the laboratory level, and a realistic response is expected to be greatly enhanced in the future. .

[0005] However, depending on the soil condition, the activity of the decomposing bacteria cannot be sufficiently increased, and it takes a long time to decompose the contaminants in the contaminated soil. There is a concern that this will be impossible.

Also, by mixing and agitating quicklime in the contaminated soil, heat of hydration is generated due to a chemical reaction between moisture contained in the contaminated soil and quicklime, and the heat of hydration is used by utilizing the heat of hydration. A method of vaporizing an organic chlorine compound, which is described in Japanese Patent Application Laid-Open No. 7-275837, has also been studied and developed.
However, in such a method, there is a concern that the contaminated soil becomes strongly alkaline due to quicklime, and after the backfill, the alkaline component diffuses into groundwater or the like or adversely affects the ecosystem.

Further, there are a method of sucking air in the soil from the contaminated soil and a method of pumping groundwater in the soil, a method of heating the contaminated soil to a high temperature, a method using a reducing action of iron powder, and the like. Groundwater pumping takes a long time and costs to maintain the facilities during that time, high-temperature heating methods have a negative effect on the ecosystem of soil, and reduction methods using iron powder have great limitations on the applicable situations. Had occurred.

[0008] The present invention has been made in view of the above-mentioned circumstances, and it is possible to remove organic chlorine compounds reliably and in a short period of time without any adverse effect on treated soil and on any contaminated soil. An object of the present invention is to provide a method, an apparatus, and a system for treating an organic chlorine compound.

[0009]

According to the present invention, there is provided a method for treating an organic chlorine compound according to the present invention.
As described in, place a pair of electrodes on a contaminated medium such as contaminated soil containing organic chlorine compounds, contaminated water, contaminated waste,
Next, the organic chlorine compound is electrolyzed by applying a current between the electrodes.

[0010] The apparatus for treating an organochlorine compound according to the present invention comprises a storage tank for storing a contaminated medium such as contaminated soil, contaminated water and contaminated waste containing the organochlorine compound. A pair of electrodes disposed in the storage tank,
And a power source electrically connected to the electrodes.

In the apparatus for treating an organochlorine compound according to the present invention, a water collecting hole is formed in a storage body such as a side plate and a bottom plate of the storage tank, and the storage tank is formed in the contaminated soil or the contaminated waste. It is constructed so that it can be buried.

Further, the system for treating an organic chlorine compound according to the present invention, as described in claim 4, is a water collecting means buried in contaminated soil containing an organic chlorine compound, and water is collected by the water collecting means. A pump for pumping groundwater, a storage tank for storing the pumped groundwater, a pair of electrodes provided in the storage tank, and a power supply electrically connected to the pair of electrodes. .

According to a fifth aspect of the present invention, there is provided a system for treating an organochlorine compound, wherein the pair of electrodes is embedded in contaminated soil containing the organochlorine compound, and is electrically connected to the pair of electrodes. Power supply.

Further, the system for treating an organic chlorine compound according to the present invention includes a water supply means for supplying water to the contaminated soil.

Further, in the system for treating an organic chlorine compound according to the present invention, a predetermined water blocking wall is provided in the contaminated soil near the water collecting means or the electrode.

In the method for treating an organochlorine compound according to the present invention, a pair of electrodes is disposed on a contaminated medium such as contaminated soil, contaminated water, and contaminated waste containing the organochlorine compound. Also,
In the apparatus for treating an organic chlorine compound according to the present invention, the above-described contaminated medium is stored in the storage tank so that the pair of electrodes is disposed in the storage tank. In the system for treating an organochlorine compound according to the present invention, the groundwater in the contaminated soil containing the organochlorine compound is collected by a water collecting means, and the collected water is pumped by a water pump to form a storage provided with a pair of electrodes. Either store in a tank or bury a pair of electrodes directly in contaminated soil.

Next, a current is applied between the above-mentioned electrodes. In this way, harmful organic chlorine compounds such as trichlorethylene and tetrachloroethylene are electrolyzed mainly to chlorides such as chloride ions and hydrocarbons such as ethylene and ethane by a reduction reaction on the cathode surface. And
Since all of these chlorides and hydrocarbons are harmless substances, harmful organic chlorine compounds are eventually rendered harmless.

In the apparatus for treating an organochlorine compound according to the present invention, a storage tank as a component thereof may be installed on the ground, and a contaminated medium may be charged or flow into the storage tank. In the case where a water collecting hole is formed in a storage body such as a side plate and a bottom plate, and the storage tank is configured to be buried in the contaminated soil or the contaminated waste, groundwater or contaminated waste in the contaminated soil is used. Exudate is collected and stored in a storage tank through a water collection hole, and groundwater and exudate are electrolyzed in the storage tank. Therefore, it is not necessary to separately pump the groundwater of the contaminated soil and the seepage water of the contaminated waste with a pump.

In the system for treating an organic chlorine compound according to the present invention, if a water supply means for supplying water to the contaminated soil is provided, the system can be applied even when the level of groundwater is low. Further, if a predetermined water blocking wall is provided near the water collecting means or the electrode in the contaminated soil, the ground water can be efficiently collected by the water collecting means and the electrode even when there is a flow in the ground water. In addition, it is possible to prevent the groundwater from diffusing into the surroundings.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method, apparatus and system for treating an organic chlorine compound according to the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

(First Embodiment)

FIG. 1 is a conceptual diagram showing an apparatus for treating an organic chlorine compound according to this embodiment. As can be seen from the figure, the treatment apparatus 1 for an organochlorine compound according to the present embodiment comprises:
A storage tank 2 in which contaminated water 5 as a contaminant containing an organic chlorine compound is stored, an anode 3a and a cathode 3b serving as a pair of electrodes disposed in the storage tank, and an anode 3a and a cathode 3b And a power supply 4 which is electrically connected.

The anode 3a and the cathode 3b are, for example,
The power supply 4 is disposed at a distance of several tens of cm, for example, 10 to 30
It is preferable that a DC voltage of about volts be applied.

Here, the storage tank 2 is arranged inside the cooling tank 6, and the contaminated water 5 is cooled by cooling water circulated and supplied from the cooling device 7.

In order to carry out the method for treating an organic chlorine compound according to the present embodiment using the apparatus 1 for treating an organic chlorine compound according to the present embodiment, first, a pair of anode 3a and cathode 3b is used.
The contaminated water 5 containing the organic chlorine compound is stored in the storage tank 2 in which the storage tank 2 is disposed.

In order to store the contaminated water 5, for example, water pumped from contaminated soil may be pumped and supplied to the storage tank 2.

Next, 10 to 3 is applied between the anode 3a and the cathode 3b.
A direct current is applied by applying a direct voltage of about 0 volt.

Thus, trichloroethylene,
Harmful organic chlorine compounds such as tetrachloroethylene are mainly electrolyzed into chlorides such as chloride ions and hydrocarbons such as ethylene and ethane by a reduction reaction on the cathode surface. And, since these chlorides and hydrocarbons are all harmless substances, harmful organic chlorine compounds are eventually rendered harmless. It should be noted that any reaction products such as chlorides and hydrocarbons are harmless and need not be particularly recovered. However, if necessary, the storage tank 2 is covered, and the gas in the storage tank is sucked. You may make it collect | recover.

Here, when the amount of electricity is increased, the processing speed of the organic chlorine compound by electrolysis is increased, but on the other hand, energy efficiency is reduced due to generation of Joule heat, and the organic chlorine compound is converted into electric power by a rise in water temperature due to the generated heat. Equipment for treating the vaporized gas without being decomposed is required separately.

Therefore, when performing the above-described energizing operation, the magnitude of the voltage and current, the energizing time, and the cooling bath 6 are set so that the processing speed by electrolysis is improved as much as possible within a range in which the vaporization of the organic chlorine compound is suppressed. It is desirable to appropriately adjust the degree of cooling by the cooling device 7.

Incidentally, when the contaminated water 5 is groundwater pumped from contaminated soil, the electric conductivity of the groundwater is about 0.1 to 0.3 mS / cm. The value is small and therefore the power consumption is also small.

Next, the effects of the apparatus and method for treating an organic chlorine compound according to the present embodiment have been confirmed by experiments, and the outline thereof will be described below.

First, contaminated water containing 100 mg / L of trichlorethylene (hereinafter referred to as TCE), which is an organic chlorine compound, is placed in a container, electrodes are installed in the container, and a direct current is passed (current value 0.05 A, The voltage value was 30 V), and the amount of chlorine gas generated at that time and the remaining amount of TCE were measured. Note that T
To minimize the loss due to volatilization of CE, the vessel was cooled by placing it in cooling water as described above.

In the measurement, the case where the energization time is different is performed four times, and after completion of the energization, a sample solution is sampled, and the TCE concentration, chloride ion (Cl ⁻ ) concentration and chlorine (Cl ⁻ )
₂ ) The concentration was measured.

FIG. 2 is a graph showing the results of the experiment. As can be seen from the figure, when current is applied, the TCE concentration (expressed as TCE residual rate) decreases with the energization time, and the chloride ion concentration (expressed as TCE chlorination rate) increases. . This is probably because chlorine, which is one of the constituent components of TCE, is eliminated from TCE by the reduction reaction mainly on the cathode surface, that is, a dechlorination reaction occurs, and TCE is reduced. The chlorine concentration was almost zero in each case.

From the above experimental results, it was found that the TCE in the contaminated water could be reliably decomposed and made harmless in proportion to the energization time, and the power required for it was very small. In addition,
When left unpowered, the TCE concentration remained almost unchanged and no chloride ions were detected. In addition, it has been confirmed that other organic chlorine compounds such as trichloroethylene, dichloroethylene, and tetrachloroethylene exhibit the same treatment effect.

As described above, according to the method and the apparatus 1 for treating an organochlorine compound according to the present embodiment, the contaminated water 5 containing the organochlorine compound stored in the storage tank 2 is converted into the anode 3a and the cathode 3b. The organic chlorine compound is electrolyzed into chlorides and hydrocarbons,
Thus, the organic chlorine compound can be rendered harmless. Moreover, since the organic chlorine compound can be detoxified with a small amount of power and in proportion to the energizing time,
It is possible to easily construct a processing device with low running cost and easy control.

In the storage water 2, not only contaminated water but also contaminated media such as contaminated soil and contaminated waste can be stored. Even so, the organic chlorine compound in the contaminated medium can be reliably treated.

Further, according to the method and apparatus 1 for treating an organic chlorine compound according to the present embodiment, since the storage tank 2 is cooled by the cooling tank 6, the degree of cooling by the cooling tank 6 is appropriately set. This makes it possible to secure a large amount of electricity without substantially vaporizing the organic chlorine compound, and thus it is possible to quickly detoxify the organic chlorine compound.

In the present embodiment, the pair of electrodes 3a and 3b are arranged in the storage tank 2. However, the storage tank 2 itself may be formed of a conductor and used as the electrode 3a or the electrode 3b.

In the present embodiment, the storage tank 2 is cooled by the cooling tank 6 in order to suppress the vaporization of the organic chlorine compound. However, the energizing conditions such as the voltage value, the current value, the energizing time, and the energizing cycle are controlled. The cooling tank 6 and the cooling device 7 may be omitted as long as the vaporization of the organic chlorine compound can be suppressed by appropriately setting.

In this embodiment, the contaminated water is used as a contaminated medium, and the contaminated water is stored in the storage tank 2 provided with the anode 3a and the cathode 3b. In the case of waste, these contaminated media are first charged into the storage tank 2, and then the anode 3a and the cathode 3b
May be arranged so as to be embedded in the contaminated medium.

In this embodiment, it is assumed that the storage tank 2 is installed on the ground, and the contaminated medium is charged or flows into the storage tank. Thus, the configuration shown in FIG.

An apparatus 1 for treating an organic chlorine compound shown in FIG.
1 is a contaminated water 5 as a contaminated medium containing an organochlorine compound.
A storage tank 12 also serving as an electrode, an electrode 13 disposed in the storage tank, and a power supply 4 electrically connected to the electrode and the storage tank 12. The electrode 13 and the storage tank Reference numeral 12 functions as a pair of electrodes. Note that one is a cathode and the other is an anode, but either may be selected.

Here, the storage tank 12 has a structure in which a large number of water collecting holes 14 are formed in the side plate 17 and the bottom plate 16 which are the storage main body, and can be buried in the contaminated soil 15 which is the contaminated medium.

In such a configuration, the groundwater in the contaminated soil 15 is collected and stored in the storage tank 12 through the water collection hole 14, and is electrolyzed by the electrode 13 and the storage tank 12 in the storage tank. Needless to say, the treated water in the storage tank 12 may be pumped by a water pump or buried in contaminated waste instead of the contaminated soil 15 as necessary.

Further, the method for treating an organic chlorine compound according to the present embodiment is applied to the treatment apparatus 1 in which the anode 3a and the cathode 3b are disposed in the storage tank 11 as described with reference to FIG. The method for treating an organochlorine compound according to the present invention is not necessarily limited to application to such a treatment apparatus 1, that is, contaminated media such as contaminated soil, contaminated water, and contaminated waste containing an organochlorine compound. The anode 3a and the cathode 3b may be disposed in this state, and the current may be supplied in this state in the same manner as described above.

(Second Embodiment)

Next, a second embodiment will be described. In addition, the same reference numerals are given to components and the like that are substantially the same as those in the above-described embodiment, and description thereof is omitted.

FIG. 4 is a conceptual diagram showing a system for treating an organic chlorine compound according to this embodiment. As can be seen from the figure, an organic chlorine compound treatment system 21 according to the present embodiment includes a water collecting pipe 22 as water collecting means buried in a contaminated soil 15 containing an organic chlorine compound, and water collecting in the water collecting pipe. Pump 23 for pumping the pumped ground water 25, a storage tank 2 for storing the pumped ground water, an anode 3a and a cathode 3b as a pair of electrodes provided in the storage tank, and these anodes 3a and 3b. It comprises a power source 4 electrically connected to the cathode 3b. The water collecting pipe 22 has a large number of water collecting holes 24 for collecting groundwater in the contaminated soil 15.

To treat an organic chlorine compound using the organic chlorine compound treatment system 21 according to the present embodiment, first, groundwater 25 in the contaminated soil 15 containing the organic chlorine compound is used.
Is collected by a water collecting pipe 22 and pumped up by a water pump 23 to be stored in the storage tank 2.

Next, 10 to 3 is set between the anode 3a and the cathode 3b.
A direct current is applied by applying a direct voltage of about 0 volt.

By doing so, as in the first embodiment,
Harmful organic chlorine compounds such as trichlorethylene and tetrachlorethylene contained in the groundwater 25 are mainly electrolyzed into chlorides such as chloride ions and hydrocarbons such as ethylene and ethane by a reduction reaction on the cathode surface. And, since these chlorides and hydrocarbons are all harmless substances, harmful organic chlorine compounds are eventually rendered harmless. The other operation and effects are substantially the same as those of the first embodiment, and the description thereof is omitted here.

As described above, according to the organochlorine compound treatment system 21 according to the present embodiment, the groundwater 25 containing the organochlorine compound stored in the storage tank 2 is supplied to the anode 3
Since the electrolysis is carried out at a and the cathode 3b, the organic chlorine compound is electrolyzed to chlorides and hydrocarbons, thus making the organic chlorine compound harmless. Moreover, since the organic chlorine compound can be detoxified with a small amount of electric power and in proportion to the energizing time, it is possible to easily construct a processing system with low running cost and easy control.

Although not specifically mentioned in the present embodiment, as shown in FIG. 5, a water supply pump 31 and a water supply pipe 32 are provided as water supply means for supplying water to the contaminated soil 15 and the water is pumped by the water supply pump. If the waste water is supplied into the contaminated soil 15 via the water supply pipe 32, the present system can be applied even when the groundwater level is low.

Although not particularly mentioned in the present embodiment, as shown in FIG. 6, a water stop wall 41 is constructed near the water collecting pipe 22 as a water collecting means by, for example, a continuous underground wall construction method. Is also good. In this configuration, the groundwater flow is blocked by the water blocking wall 41 in the contaminated soil 15, so that even if there is a flow in the groundwater, the groundwater can be efficiently collected in the collecting pipe 22 and the groundwater can be collected. It is also possible to prevent diffusion to the surroundings.

(Third Embodiment)

Next, a third embodiment will be described. In addition, the same reference numerals are given to components and the like that are substantially the same as those in the above-described embodiment, and description thereof is omitted.

FIG. 7 is a conceptual diagram showing a system for treating an organic chlorine compound according to the present embodiment. As can be seen from the figure, an organic chlorine compound treatment system 51 according to the present embodiment includes an anode 3a and a cathode 3b as a pair of electrodes buried in a contaminated soil 15 containing an organic chlorine compound, and the anode 3a And a power supply 4 electrically connected to the cathode 3b.

To treat an organochlorine compound using the organochlorine compound treatment system 51 according to the present embodiment, as in each of the above-described embodiments, one anode electrode 3a and one cathode 3b are disposed.
A direct current is applied by applying a direct voltage of about 0 to 30 volts.

In this way, as in the first and second embodiments, the harmful organic chlorine compounds such as trichlorethylene and tetrachloroethylene are mainly converted into chlorides such as chloride ions by the reduction reaction of the cathode surface and carbonized gases such as ethylene and ethane. Electrolyzed to hydrogen. And, since these chlorides and hydrocarbons are all harmless substances, harmful organic chlorine compounds are eventually rendered harmless.

The above embodiment is substantially the same as the above embodiment except that the electrolysis reaction proceeds not in the storage tank 2 or the storage tank 12 but in the contaminated soil 15 around the anode 3a and the cathode 3b. Yes, other effects are omitted here, but the present embodiment is particularly suitable for gravel ground with few colloid particles, and efficiently removes organochlorine compounds contained in the gravel ground in situ. It has a remarkable function and effect that it can be rendered harmless, and a remarkable function and effect that it does not have any adverse effect on contaminated soil unlike the conventional method using quick lime.

In this embodiment, the water supply pump 31 and the water supply pipe 32 as the water supply means as described in the second embodiment are provided to supply water to the contaminated soil 15 and raise the level of groundwater. It may be.

Similarly, by constructing a water blocking wall 41 near the anode 3a and the cathode 3b by, for example, a continuous underground wall construction method, the flow of the groundwater is blocked in the contaminated soil 15 by the water blocking wall 41. Is also good. According to this configuration, even when there is a flow in the groundwater, the groundwater can be efficiently collected around the anode 3a and the cathode 3b, and the diffusion to the surroundings of the groundwater can be prevented.

[0065]

As described above, according to the method, apparatus and system for treating an organic chlorine compound according to the present invention,
The organic chlorine compound can be removed reliably and in a short time without any adverse effect on the treated soil and on any contaminated soil.

[0066]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an apparatus for treating an organic chlorine compound according to a first embodiment.

FIG. 2 is a graph showing an operation of the apparatus for treating an organic chlorine compound according to the first embodiment.

FIG. 3 is a conceptual diagram showing an apparatus for treating an organic chlorine compound according to a modification.

FIG. 4 is a conceptual diagram showing an organic chlorine compound treatment system according to a second embodiment.

FIG. 5 is a conceptual diagram showing an organic chlorine compound treatment system according to a modification.

FIG. 6 is a conceptual diagram showing an organic chlorine compound treatment system according to another modification.

FIG. 7 is a conceptual diagram showing a system for treating an organic chlorine compound according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 11 Organochlorine compound processing apparatus 2 Storage tank 3a, 3b electrode 4 Power supply 5 Contaminated water (contaminated medium) 12 Storage tank, electrode 13 Electrode 14 Water collecting hole 15 Contaminated soil (contaminated medium) 16 Bottom plate (storage main body) 17 Side plate (storage body) 21, 51 Organochlorine compound treatment system 22 Water collecting pipe (water collecting means) 23 Pumping pump 31 Water supplying pump (water supplying means) 32 Water supplying pipe (water supplying means) 41 Water stop wall

Continued on the front page (72) Inventor Toshihiko Miura 4-640 Shimoseito, Kiyose-shi, Tokyo F-term in Obayashi Corporation Technical Research Institute Co., Ltd. 4D004 AA41 AB06 CA40 CA44 CB01 CC03 4D061 DA08 DB19 DC09 EA04 EB19

Claims (7)

[Claims] 1. A method comprising: disposing a pair of electrodes on a contaminated medium such as contaminated soil, contaminated water, and contaminated waste containing an organochlorine compound, and then electrolyzing the organochlorine compound by applying a current between the electrodes. A method for treating an organic chlorine compound. 2. A storage tank for storing a contaminated medium such as contaminated soil, contaminated water, and contaminated waste containing an organochlorine compound, a pair of electrodes disposed in the storage tank, and an electrical connection to the electrodes. An organic chlorine compound processing apparatus, comprising: a power supply; 3. A water collecting hole is formed in a storage body such as a side plate and a bottom plate of the storage tank, and the storage tank can be embedded in the contaminated soil or the contaminated waste.
An apparatus for treating an organic chlorine compound as described in the above. 4. A water collecting means buried in contaminated soil containing an organochlorine compound, a pump for pumping groundwater collected by the water collecting means, and a storage tank for storing the pumped groundwater. An organic chlorine compound treatment system, comprising: a pair of electrodes provided in the storage tank; and a power supply electrically connected to the pair of electrodes. 5. A system for treating an organochlorine compound, comprising: a pair of electrodes buried in contaminated soil containing an organochlorine compound; and a power supply electrically connected to the pair of electrodes. 6. The organic chlorine compound treatment system according to claim 4, further comprising a water supply means for supplying water to the contaminated soil. 7. The organic chlorine compound treatment system according to claim 4, wherein a predetermined water stop wall is provided in the contaminated soil near the water collecting means or the electrode.