JP2003080222A - Method of removing contaminant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient method of completely removing contaminants included in soil and, in particular, of removing heavy metals hardly movable in the soil. SOLUTION: Contaminant catching bodies are disposed in the contaminated soil and fluid injection pipes are partly or wholly inserted into the contaminated soil. The fluid is injected into the contaminated soil through the fluid injection pipes and the contaminant catching bodies catch the contaminants moving near to the contaminant catching bodies under a reduced pressure vacuum sucked. A plurality of the fluid injection pipe are installed at a prescribed interval and the fluid injection pipes have a plurality of holes on their peripheral surfaces. The one-side of edges is coupled to a compressor which injects pressured fluid into the fluid injection pipe. The fluid is an acidic liquid and makes the pH of the contaminated soil to 3 to 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for promoting purification of polluted soil containing pollutants, polluted soil deposits, waste deposits, etc., in the technical field of removing harmful substances and purifying pollutants. .

[0002]

2. Description of the Related Art Various methods have been proposed and implemented as methods for cleaning contaminated soil. For example, JP-A-11
No. 169836 discloses a process of constructing a culvert by drilling a plurality of horizontal wells at predetermined intervals below a contaminated zone existing in an unsaturated zone, and a contaminant penetrating from the ground surface into the contaminated zone The method includes the steps of forcibly collecting the dissolved gravity water from the screen formed in each horizontal well, and the step of discharging the collected gravity water. Techniques for preventing migration to layers are disclosed.

Further, in Japanese Patent Laid-Open No. 11-156351, cylinders containing a metal-based reducing agent or an adsorbent capable of obtaining higher water permeability than an aquifer are arranged in rows in the ground. Process for injecting a metal-based reducing agent into a contaminated area of groundwater and a contaminated area of groundwater, or a stirring and mixing step of agitating and mixing the metal-based reducing agent or adsorbent with soil located in the contaminated area of groundwater A purification method including is disclosed.

As a technique relating to the removal of heavy metals, Japanese Patent Application Laid-Open No.
Japanese Patent Publication No. 000-102776 discloses a technique of using a treating agent prepared by mixing an appropriate amount of a specific type of inorganic reducing agent with cement and applying heat treatment. In addition, JP 20
In Japanese Patent Publication No. 00-51835, water, an iron powder, and a chemical that promotes the movement of heavy metals are added to soil contaminated with heavy metals, and the mixture is stirred, and the heavy metals in the soil are adsorbed on the iron powder. A technique for separating from soil using a wet magnetic separator is disclosed. Further, in JP-A-11-165147, a heavy metal-containing waste treatment agent containing granulated blast furnace slag and a pozzolanic active substance, a heavy metal-containing waste, and stabilization of a heavy metal-containing waste obtained by mixing and kneading water A treatment method is disclosed. Further, Japanese Patent Laid-Open No. 10-146577 discloses a method for stabilizing a heavy metal-containing waste using a pozzolanic active substance. Further, Japanese Patent Application Laid-Open No. 10-71386 discloses an in-situ reduction method of soluble and insoluble heavy metals and organic halogen compounds by pneumatic fracturing with iron powder injection to purify contaminated soil and groundwater. ing.

As a technique for removing organic chlorine compounds, a vacuum suction technique (soil gas suction method) for soil gas (air in the gaps between soils) is generally used. In this method, pollutants existing in the stratum above the groundwater level are forcibly removed by suction to clean the contaminated soil. Specifically, by installing a suction well in the soil by boring,
A vacuum pump depressurizes the suction well to guide the vaporized pollutants to the ground and remove them by adsorption with activated carbon. If the pollution extends to the aquifer, a submersible pump will be installed inside the suction well and the double suction method will also be used to pump groundwater. For soils with a relatively shallow groundwater level, a method of sucking both soil gas and groundwater pollution together is also used. Besides this,
A large number of auxiliary construction methods have been developed, such as the method of using a horizontal well as the suction well and the air sparging method of injecting air into the saturated zone to promote volatilization from groundwater.

As a technique for removing volatile organic compounds (VOCs), volatile organic compounds (VOCs) have a high material mobility and are easily separated and decomposed.
The containment technology that is often used for heavy metals is not applied, and purification technology that removes pollutants is common.

Further, as a technology for removing hydrocarbon-based pollution such as benzene, there is a biodegradation technology. In particular, light oils such as benzene are easily decomposed, so simple methods such as excavating contaminated soil, spreading it thinly on a flat land, and plowing it in (land farming, etc.) are being used. In addition, recently, a microorganism that efficiently decomposes volatile organic chlorine compounds such as trichlorethylene has been found, and is being studied for practical use.

In addition to the above, Japanese Patent Laid-Open No. 11-77019 discloses a soil purification method in which microorganisms are added to soil contaminated with an organic halogen compound.
A method is disclosed in which the pH of soil is adjusted to a specific range so that soil purification can always be performed efficiently regardless of the type of soil.

In addition to the above, as a method utilizing chemical decomposition, a method of dechlorinating contaminated groundwater with volatile organic chlorine compounds using iron powder has been put into practical use.
In addition, a method (groundwater pumping method) of treating groundwater and soil pollution by pumping contaminated groundwater and removing / recovering pollutants has been proposed. Aeration treatment, activated carbon adsorption treatment and chemical decomposition can be applied as a treatment method of the pumped-up contaminated groundwater, but aeration treatment has been widely used. In addition, for the polluted soil excavated,
There are also methods such as wind-drying and heating to remove and recover pollutants, and techniques to oxidize organic chlorine compounds with potassium permanganate in situ. In addition to the method of mechanically cleaning soil to remove contaminants as described above, a method of injecting a solvent in situ to clean soil (called soil flushing) has also been proposed.

[0010]

Here, since heavy metals have relatively low mobility in the environment, a method of solidifying and insolubilizing heavy metals and enclosing them in a water-impervious structure is generally used. However, the method of confining heavy metals in the soil does not completely clean the contaminated soil. In addition, there is a risk that the contained pollutants will leak into the soil after a long time.

Further, in the conventional method for removing contaminated soil containing heavy metals, it is necessary to excavate the soil and stir and mix chemicals and iron powder, which requires enormous cost and time for construction. .

Therefore, the method for removing pollutants according to the present invention can remove pollutants, such as heavy metals, which are difficult to move in the polluted soil, from the polluted soil, and can efficiently remove the pollutants. It is an object of the present invention to provide a technique capable of removing the.

[0013]

In order to solve the above-mentioned problems, a method for removing pollutants according to the present invention provides a pollutant trap in polluted soil containing pollutants, and a liquid or gas in polluted soil. Insert part or all of the fluid injection pipe for injecting into the contaminated soil, inject the liquid or gas into the contaminated soil via the fluid injection pipe, and remove the contaminants that have moved to the vicinity of the contaminant trap. A method for removing a pollutant captured by a pollutant trap, wherein the fluid injection pipe has one insertion part inserted into the contaminated soil, or a plurality of insertion parts having a predetermined interval. Is characterized by.

Further, it is characterized in that the contaminant capturing body is decompressed to capture the contaminants.

Further, the fluid injection pipe is characterized in that it has a plurality of holes on its peripheral surface.

Further, the fluid injection pipe is characterized in that it has a connecting means at its peripheral portion.

Further, one edge of the fluid injection pipe is connected to a compression device, and the compression device injects a pressurized fluid into the fluid injection pipe.

Further, the fluid injection pipe is provided with a mechanism for preventing backflow dissipation of liquid or gas.

Further, the present invention is characterized in that a water-swellable resin coating film is formed on a part or all of the outer peripheral surface of the fluid injection pipe.

Further, the water-swellable coating film is characterized in that it is one of a mixture of an acrylic binder resin, a polyacrylic acid water absorbing resin, and an organic solvent.

The liquid injected into the contaminated soil via the fluid injection pipe is an acidic liquid.

Further, the present invention is characterized in that an acidic liquid is injected into the contaminated soil through a fluid injection pipe to adjust the pH of the contaminated soil to 3 to 6.

The gas injected into the contaminated soil through the fluid injection pipe is oxygen-enriched air.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for removing contaminants according to the present invention will be described with reference to the drawings. 1 and 2 are explanatory views illustrating a method for removing contaminants according to the present invention. Fig. 1 shows that when the fluid injection pipe 2 is inserted vertically into the soil,
FIG. 2 shows a case where the fluid injection pipe 2 is inserted horizontally with respect to the soil. In the method for removing pollutants according to the present invention, a pollutant trap 16 is provided in a polluted soil 18 containing pollutants, and a part or all of a fluid injection pipe 2 for injecting a liquid or gas into the polluted soil 18. Inserted into the contaminated soil 18,
A liquid or gas is injected into the contaminated soil 18 through the fluid injection pipe 2, and the pollutant that has moved to the vicinity of the pollutant trap 16 is trapped by the pollutant trap 16. Further, the insertion portion of the fluid injection pipe 2 inserted into the contaminated soil 18 has a plurality of insertion portions at a predetermined interval.

Here, the soil referred to in the present invention is not limited to the soil in a narrow sense, but the waste that is dumped and accumulated,
It also includes a contaminated soil product in which the contaminated soil 18 is deposited. Also,
Containing pollutants means that when pollutants adhere to soil particles or waste, when water present in the gaps between soil particles and waste contains pollutants, groundwater contains pollutants. In this case, it means that the pollutant is present in the soil (ground) in some form, such as when the pollutant remains as it is in the gaps between soil particles and waste. Further, the soil referred to in the present invention refers to either or both of an unsaturated zone above the water table and an aquifer below the water table.

Next, the pollutant trap 16 according to the present invention
Consists of a pollutant trapping material and a container containing the pollutant trapping material. As this container, a bag-shaped container, a substantially cylindrical wall body 14 having a plurality of holes, or the like can be used. In the case of a bag-shaped container, it is preferable to use a material having good durability, air permeability, and water permeability, and fibers such as cloth and hemp, a vinyl net, and a wire net can also be used. As the shape, it is easy to use a substantially mat shape or a substantially ball shape, but it may be set appropriately.

FIG. 10 is an explanatory view showing the wall body 14 according to the present invention. The wall 14 has a plurality of holes on its peripheral surface. The wall body 14 is made of a material such as steel, other metal, or resin, and has a plurality of holes on the wall surface. The wall 14 may not have a bottom. The pollutant trapping material may be directly loaded inside the wall body 14, or the pollutant trapping body 16 in which the pollutant trapping material is put in a bag-shaped container may be loaded.

As the pollutant trapping material, a wide range of materials such as activated carbon, charcoal, mineral trapping materials such as zeolite (having adsorption and ion exchange functions) can be selected. The pollutant trapping material may be either powdery or granular, but granular is often easier to handle. The granular shape is not necessarily spherical but may be cylindrical or the like. In the case of a cylindrical shape, the voids are large when randomly arranged, the mass transfer in the trapping material layer is facilitated, and the trapping of the pollutant is effectively performed. As the charcoal, carbonized wood waste can also be used.

To install the pollutant trap 16
A well in the horizontal or vertical direction is formed in the soil, and the pollutant trap 16 is installed in this well.

For example, when using a vertical well,
A method of removing a pollutant in which a wall having a plurality of holes is installed on the peripheral surface of the well and the pollutant trapping material is directly charged into the well can be used. That is, after the pollutant trapping material charged into this well traps the pollutant, the pollutant trapping material is recovered from the well, and the pollutant trapping material is newly charged into the well, thereby It is intended to remove pollutants. This wall may be the same as that shown in FIG.

When a horizontal well is used,
A method in which a wall having a plurality of holes is installed in the well and the pollutant trapping material is directly charged into the well can also be used. At this time, the pollutant can be collected by depressurizing the pollutant trapping material. Further, a method of using the pollutant trap 16 in which the pollutant trapping material is put in a bag-shaped container in the horizontal well can also be used. At this time, the contaminant trap may be collected and a new contaminant trap may be inserted. This wall may be the same as that shown in FIG.

Further, in the removal of the pollutant according to the present invention, the pollutant trap 16 is depressurized to remove the pollutant. By reducing the pressure of the pollutant trap 16, the pollutant that has moved to the vicinity of the pollutant trap 16 can be easily trapped, and the pollutant trapped by the pollutant trap 16 can be stored in the pollutant trap 16. It can be moved and pollutants can be recovered. Here, the contaminant trap 16
If the suction force of the is larger than the suction force of the vacuum suction, the contaminant capturing body 16 is still trapping the contaminant, but if the suction force is larger than the capturing force, the contaminant moves to the vacuum suction side. To do. Therefore, it is necessary to reduce the pressure of the contaminant trap 16 while paying attention to the balance between the trapping force of the contaminant trap 16 and the suction force for vacuum suction. As a method of reducing the pressure, it is preferable to suck the pollutant trap 16 by vacuum with a fan, a blower, a compressor, or the like.

Next, the fluid injection pipe 2 according to the present invention will be described with reference to FIG. The fluid injection pipe 2 according to the present invention is a part or all of which is inserted into soil to inject a liquid or gas into the soil. The insertion direction of the fluid injection pipe 2 does not matter whether it is the vertical direction or the horizontal direction with respect to the ground.

The fluid injection pipe 2 is used in one or a plurality, and as shown in the drawing, a plurality of holes 4 are formed in the peripheral surface. The formation position and the number of the holes 4 may be set appropriately. The material of the fluid injection pipe 2 is preferably a stainless steel pipe, but other materials can also be used.

The peripheral portion of the fluid injection pipe 2 has a connecting means and can be connected to another fluid injection pipe 2 or another pipe. As the connecting means, screw connection is preferable, but a fitting member may be provided, or another connecting tool may be used and may be set appropriately.

If the direction of insertion of the fluid injection pipe 2 is vertical to the soil, the tip of the insertion portion of the fluid injection pipe 2 to be inserted into the soil may have a pointed shape for easy insertion. good.

Further, as shown in FIG. 4, it is also possible to connect the fluid injection pipes 2 provided with appropriate intervals with a branch pipe 8 and use them as one unit 6. At this time, the number of fluid injection pipes 2 may be set as appropriate,
^It is easy to use by installing 9 to 16 in ² . By arranging the units 6 at equal intervals, it is possible to uniformly inject the liquid or gas into the soil and remove the contaminants evenly.

The end of the fluid injection pipe 2 or the end of the branch pipe 8 of the unit 6 is connected to a compression device.
This compression device pumps a liquid or gas and injects the liquid or gas into the soil. A compressor, a general pump, or the like can be used as the compression device, but it may be set as appropriate.

Further, the fluid injection pipe 2 may be provided with a backflow dissipation prevention mechanism 10 for liquid or gas. 6 and 8 are views showing an embodiment of the backflow dissipation prevention mechanism 10 according to the present invention. 7 and 9 are explanatory views showing a state in which the backflow dissipation prevention mechanism 10 is to be used. When the liquid or gas is injected into the soil, it is pumped from the compression device as described above, and therefore flows backward from the gap between the soil and the fluid injection pipe 2. Therefore, a backflow dissipation prevention mechanism 10 is provided to prevent backflow of liquid or gas. Moreover, since the pressurized liquid or gas is injected from the fluid injection pipe 2 into the soil, the fluid injection pipe 2 becomes unstable. Therefore, another purpose is to provide the backflow dissipation prevention mechanism 10 and fix the fluid injection pipe 2 to stabilize it.

The backflow dissipation preventing mechanism 10 is preferably of the generally tubular brim type shown in FIG. 6 or the mat type shown in FIG. 8, but may be set as appropriate. The backflow dissipation prevention mechanism 10 may be integrally formed with the fluid injection pipe 2 or may be removable. If detachable, the depth at which the fluid injection pipe 2 can be inserted can be freely adjusted. However, the fluid injection pipe 2 and the backflow dissipation prevention mechanism 10 can be adjusted.
It is necessary to be careful so that there is no gap in.

The backflow dissipation prevention mechanism 10 of the generally tubular brim type shown in FIG. 6 is preferably made of metal such as stainless steel or steel, but other materials may be used. Further, the mat-like backflow dissipation preventing mechanism 10 shown in FIG. 7 is preferably made of a material such as rubber or resin, but other materials may be used.

The fluid injection pipe 2 can be installed substantially horizontally in the soil by excavation or excavation of a horizontal hole by horizontal boring. The method of excavating a horizontal hole is to dig two pits in the intrusion pit and the arrival pit, and use a drill head attached to the rod to dig diagonally from the intrusion pit at a predetermined ground angle, then make a horizontal excavation, and finally a horizontal Dig from the ground to the ground. When the excavation is completed, a reamer connected to the fluid injection pipe 2 is attached to the tip of the rod to expand the diameter, and at the same time, the fluid injection pipe 2 is drawn into the horizontal hole. Fluid injection pipe 2
If it can be installed in a substantially horizontal direction, the contaminants according to the present invention can be removed even on a land where obstacles such as buildings already exist.

When the fluid injection pipe 2 is installed substantially horizontally,
It is also possible to connect the fluid injection pipes 2 provided with appropriate intervals with a branch pipe 8 to be used as one unit 6. The number of fluid injection tubes 2 of this unit 6 may be set appropriately.
Also at this time, the end of the fluid injection pipe 2 or the end of the branch pipe 8 of the unit 6 is connected to the compression device.

A water-swellable resin coating film may be formed on a part or all of the outer peripheral surface of the fluid injection pipe 2. This water-swellable resin coating film swells and gels with water in the soil, the liquid to be injected, or groundwater, so that a lubricous layer can be formed around the fluid injection pipe 2. This lubricating layer not only facilitates the insertion and removal of the fluid injection pipe 2, but also
Since the gap around the fluid injection pipe 2 can be closed with a lubricating layer, it is possible to prevent the backflow of the liquid or gas injected into the soil.

As the water-swellable resin coating film, it is preferable to use any of a mixture of an acrylic binder resin, a polyacrylic acid water absorbing resin and an organic solvent.
Other than this, it may be appropriately set and used.

As the liquid to be injected into the soil, water or other solution can be used, but an acidic liquid may be used. For example, when arsenic or the like is contained in the contaminated soil 18, the pollutant can be washed off with water or the like, but since heavy metals or the like are adsorbed on the soil particles, it is almost impossible to wash off with water or the like. Heavy metals generally exist in the aqueous solution in the form of hydroxides, ions, or salt molecules, but the lower the pH, the more likely they remain in the form of salt molecules. Therefore, an acidic liquid is injected into the soil, heavy metals and the like adhering to the soil particles are separated from the soil particles, and the contaminants are removed from the contaminated soil 18 by flowing out with the liquid. The acidic liquid may be appropriately set in consideration of various conditions. Carbonated water is not so strong in acidity but easy to use.

When the acidic liquid is injected, the pH of the contaminated soil is preferably about 3-6. Heavy metals such as Cd and Zn contained in the soil, which are in a loosely bound state, are released and activated along with other substances in the soil as the hydrogen ion concentration in the soil increases, and move to the liquid side. . Further, it is known that when the soil pH is in the range of 4 to 5.5, the soil moves favorably to the liquid side. It is also known that Hg and Pb also move to the liquid side in acidic soil. Therefore, by injecting an acidic liquid into the contaminated soil 18 containing pollutants, the pH of the soil is adjusted to 3 to 6
Then, the heavy metal adsorbed on the soil particles is to be separated from the soil by the liquid.

As the gas to be injected into the soil, air, other gas or gas can be used, but it is also preferable to inject oxygen-enriched air.
This is to make the polluted soil 18 aerobic,
Not only can the purification be expected to be promoted, but if the chemical state of the pollutant can be changed, it can be expected that the pollutant, which is usually difficult to remove, can be easily removed. Further, if contaminants that can be decomposed by microorganisms are removed, microorganisms can be further activated by mixing microorganisms into the contaminated soil 18 and injecting oxygen-enriched air. .

[0049]

In order to solve the above-mentioned problems, the method for removing pollutants according to the present invention is a method for removing pollutants, in which a pollutant trap is provided in a polluted soil containing pollutants, A part or all of a fluid injection pipe for injecting a liquid or gas into the contaminated soil is inserted into the contaminated soil, and the liquid or gas is injected into the contaminated soil through the fluid injection pipe, in the vicinity of the pollutant trap Since the pollutant that has moved to (1) is captured by the pollutant trap, it is possible to wash away the contaminant that is hard to move and that is contained in the contaminated soil with the liquid.

In addition, the contaminant trap is decompressed (vacuum suction).
Since the pollutants are captured in this manner, the pollutants that have moved to the vicinity of the pollutant trap can be captured efficiently, and the pollutants can be removed from the polluted soil in a short period of time.

Further, since the fluid injection pipe according to the present invention has a plurality of holes on the peripheral surface, it is possible to evenly inject a liquid or gas into the soil and remove contaminants evenly. it can.

Further, since the fluid injection pipe is provided with the liquid or gas backflow dissipation prevention mechanism, not only the backflow of the liquid or gas injected into the soil can be prevented but also the fluid injection pipe can be stably fixed. it can.

Furthermore, since a water-swellable resin coating film of a mixture of an acrylic binder resin, a polyacrylic acid water absorbent resin, and an organic solvent is formed on a part or all of the outer peripheral surface of the fluid injection pipe, the fluid injection is performed. In addition to facilitating the insertion and removal of the pipe, a lubricating layer is formed in the gap between the soil and the fluid injection pipe to prevent the backflow of the liquid or gas injected into the soil.

Further, in the method of removing pollutants according to the present invention, since the liquid to be injected into the contaminated soil is an acidic liquid, it is possible to mainly remove heavy metals adsorbed on the soil particles and the like. It is possible to remove pollutants from contaminated soil containing.

Further, in order to adjust the pH of the contaminated soil to 3 to 6 by injecting an acidic liquid into the contaminated soil, Cd, Zn,
Heavy metals such as Hg and Pb that cannot be removed with water can be separated from the soil particles, and contaminants can be removed from the contaminated soil.

In addition, in the method for removing pollutants according to the present invention, since the gas injected into the contaminated soil is air enriched with oxygen, the aerobic microorganisms that survive in the soil are activated, It can accelerate the decomposition of pollutants.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a method for removing contaminants according to the present invention.

FIG. 2 is an explanatory view showing an embodiment of a method for removing contaminants according to the present invention.

FIG. 3 is an explanatory view showing a fluid injection pipe according to the present invention.

FIG. 4 is an explanatory view showing a unit of a fluid injection pipe according to the present invention.

FIG. 5 is an explanatory view showing a unit of a fluid injection pipe according to the present invention.

FIG. 6 is an explanatory view showing an embodiment of a backflow dissipation prevention mechanism according to the present invention.

FIG. 7 is an explanatory view showing a state in which the backflow dissipation prevention mechanism according to the present invention is used.

FIG. 8 is an explanatory view showing an embodiment of a backflow dissipation prevention mechanism according to the present invention.

FIG. 9 is an explanatory view showing a state in which the backflow dissipation prevention mechanism according to the present invention is used.

FIG. 10 is an explanatory view showing a wall body according to the present invention.

[Explanation of symbols]

2 Fluid injection pipe 4 holes 6 units 8 branched tubes 10 Backflow dissipation prevention mechanism 14 walls 16 Pollutant trap 18 contaminated soil

Claims (11)

[Claims] 1. A pollutant trap is provided in polluted soil containing pollutants, and a part or all of a fluid injection pipe for injecting a liquid or gas into the polluted soil is inserted into the polluted soil, A method of removing a contaminant by injecting a liquid or a gas into the contaminated soil through the fluid injection pipe, wherein the contaminant that has moved to the vicinity of the contaminant trap is trapped by the contaminant trap, The method for removing contaminants is characterized in that the fluid injection pipe is inserted into the contaminated soil in one or a plurality of insertion portions having a predetermined interval. 2. The method for removing contaminants according to claim 1, wherein the contaminant capturing body is decompressed to capture the contaminants. 3. The method for removing contaminants according to claim 1, wherein the fluid injection pipe has a plurality of holes on its peripheral surface. 4. The method for removing contaminants according to claim 1, wherein the fluid injection pipe has a connecting means at a peripheral portion thereof. 5. One of the edges of the fluid injection pipe is connected to a compression device, and the compression device injects a pressurized liquid or a pressurized gas into the fluid injection pipe. The method for removing a contaminant according to any one of 1. 6. The method for removing contaminants according to claim 1, wherein the fluid injection pipe is provided with a mechanism for preventing backflow dissipation of liquid or gas. 7. A water-swellable resin coating film is formed on a part or all of the outer peripheral surface of the fluid injection pipe.
7. The method for removing contaminants according to any one of 6 to 6. 8. The contaminant according to claim 7, wherein the water-swellable coating film is any one of a mixture of an acrylic binder resin, a polyacrylic acid water absorbent resin, and an organic solvent. Removal method. 9. The method for removing a pollutant according to claim 1, wherein the liquid injected into the contaminated soil through the fluid injection pipe is an acidic liquid. 10. The contaminant removal according to claim 9, wherein an acidic liquid is injected into the contaminated soil through the fluid injection pipe to adjust the pH of the contaminated soil to 3 to 6. Method. 11. Removal of pollutants according to claim 1, wherein the gas injected into the contaminated soil through the fluid injection pipe is oxygen-enriched air. Method.