JP2005046658A - Soil purifying method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent soil purifying method for preventing ground water from flowing in polluted soil present in an aquifer to extend pollution and effectively purifying polluted soil without requiring much time and cost, and an apparatus therefor. <P>SOLUTION: Since the contact of ground water of the aquifer 14 with polluted soil 16 is cut off by a partition wall 20 in the soil purifying apparatus 50, the extension of pollution through ground water is effectively prevented. Since a chemical liquid is injected in the polluted oil 16 from the vicinity of the upper part thereof by a chemical liquid injection well 22, the time and cost required in purification can be reduced. Further, the ground water of the aquifer 14 is pumped up and injected using a water pumping-up well 38, an injection well 40 and connection piping 42, and the amount of water pumped-up and the amount of the chemical solution are adjusted by a control device 36 so that the chemical solution layer 30 always becomes higher than the water level of the aquifer 14 to certainly prevent the inflow of the polluted soil 16 due to the difference of a water level. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soil purification method and apparatus for purification by injecting a chemical solution into contaminated soil existing in an aquifer.
[0002]
[Prior art]
Conventionally, due to dumping of industrial waste and discharge of industrial wastewater, pollutants such as oils, heavy metals, and volatile organic compounds have entered the soil and contaminated the soil to form contaminated soil. When soil is contaminated, contaminants are leached into the groundwater flowing slowly through the aquifer, and the groundwater flow may cause widespread soil contamination and affect the living environment. For this reason, soil environment standards and groundwater purification standards are established by the Basic Environment Law and Water Pollution Control Law, and the concentrations of various substances contained in soil and groundwater are regulated.
[0003]
Various efforts have been made to purify the contaminated soil, and many purification methods have been adopted in which substances or microorganisms that promote decomposition are directly injected and treated upstream of the contaminated soil.
[0004]
In particular, in Patent Document 1, a grout zone of an impermeable layer is formed around a contaminated soil range, groundwater is taken from the inside of the grout zone, introduced into an aeration type processing apparatus, and then processed by the aeration type processing apparatus. A method for purifying contaminated soil is disclosed in which the purified water is returned again into the grout zone. By this method, expansion of the contaminated soil range due to water injection can be prevented.
[0005]
[Patent Document 1] JP-A-5-228463
[Problems to be solved by the invention]
However, in the conventional purification method and the purification method of contaminated soil of Patent Document 1, the chemical solution is injected into the contaminated soil from the horizontal direction. However, since groundwater in the aquifer flows extremely slowly, It takes a lot of time to infiltrate the chemical and purify it. Moreover, since chemical | medical solution will contact and contact with other soil before reaching | attaining contaminated soil, there exists a problem that the purification effect with respect to contaminated soil by chemical | medical solution will reduce.
[0007]
The present invention has been made in view of such circumstances, and while preventing groundwater from flowing into the contaminated soil existing in the aquifer and expanding the contamination, effective contamination without taking time and cost. An object of the present invention is to provide an excellent soil purification method and apparatus for purifying soil.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a soil purification method for treating a pollutant contained in the contaminated soil by injecting a chemical solution into the contaminated soil present in the aquifer. By blocking the upstream aquifer upstream of the contaminated soil from the flow of groundwater in the aquifer, the inflow of the groundwater into the contaminated soil is prevented, and the chemical solution is applied to the contaminated soil. Injecting and immersing the contaminated soil with the chemical solution to form a chemical solution layer, and maintaining the water level of the chemical solution layer higher than the water level of the upstream aquifer.
[0009]
Further, according to claim 2 of the present invention, when the aquifer and the contaminated soil of claim 1 are composed of loam layers having a high water permeability in the vertical direction, from above the contaminated soil, The chemical solution is injected in a vertical direction.
[0010]
The aquifer described here is a layer in which rock fractures and pores in the soil are saturated with groundwater, and the loam layer is a soil containing a small amount of organic matter and containing a suitable amount of sand, silt, and clay. It is a layer composed of In addition to soil itself, contaminated soil includes groundwater present in the soil.
[0011]
According to claims 1 and 2, when the contaminated soil existing in the aquifer is purified, the groundwater flows from the aquifer into the contaminated soil and comes into contact with the pollutants contained in the contaminated soil. Contamination and the contaminated groundwater can increase soil contamination. Therefore, by blocking the upstream side of the contaminated soil from the groundwater flow in the aquifer, the groundwater flowing through the aquifer can be prevented from flowing into the contaminated soil.
[0012]
After blocking the flow of groundwater in this manner, the chemical solution can be effectively injected into the contaminated soil in a short time by injecting the chemical solution from above the contaminated soil. This is because when the aquifer and the contaminated soil are loam layers composed of highly permeable soil in the vertical direction, it is shorter to inject vertically than to inject horizontally into the contaminated soil. This is because the chemical solution can be effectively permeated and a chemical solution layer immersed in a high water level can be formed without diffusing horizontally in the contaminated soil.
[0013]
In addition, by injecting the chemical from the vicinity of the contaminated soil, contact with the soil other than the contaminated soil is reduced, so that it is suppressed as much as possible from reacting with the components contained in the uncontaminated soil, The amount of the chemical used for purification can be reduced.
[0014]
The flow of groundwater in the aquifer tends to flow from higher to lower water levels and pressures. On the other hand, in the loam layer, the chemical solution permeates more easily in the vertical direction than in the horizontal direction. Therefore, the chemical solution layer can be formed at a high water level without spreading in the lateral direction. Therefore, by maintaining the water level of the chemical layer higher than the level of the aquifer, it is possible to prevent the groundwater of the aquifer from flowing into the chemical layer and reducing the concentration of the chemical in the chemical layer. On the other hand, the purification by injecting the chemical solution can be performed more effectively.
[0015]
Thus, the time and cost required for purification can be significantly reduced by purifying contaminated soil by combining the blocking of groundwater and the formation of a chemical solution layer.
[0016]
Claim 3 of the present invention draws out the groundwater of the upstream aquifer of claim 1 or 2 and injects it into the downstream aquifer downstream of the contaminated soil with respect to the flow of groundwater in the aquifer. It is characterized by doing.
[0017]
According to claim 3, when the aquifer is blocked and there is no other direction in which the groundwater flows, there is a possibility that the water level of the aquifer rises with time and becomes higher than the water level of the chemical liquid layer. . Since groundwater tends to flow from a higher water level to a lower water level, groundwater flows from the aquifer to the chemical solution layer and the contaminated soil by going around the blocked location or passing through the gap. If the groundwater flows into the chemical solution layer and the contaminated soil, not only the concentration of the chemical solution in the chemical solution layer is lowered, but also there is a possibility that the contaminants are eluted from the contaminated soil that has not been purified to contaminate the groundwater. Therefore, once the groundwater is withdrawn from the blocked aquifer and the groundwater is pumped into the contaminated soil at a position downstream of the flow of groundwater, the water level of the blocked aquifer increases. Can be effectively prevented.
[0018]
According to a fourth aspect of the present invention, there is provided a soil purification apparatus for treating a pollutant contained in the contaminated soil by injecting a chemical solution into the contaminated soil present in the aquifer to achieve the object. An impermeable partition that blocks the upstream aquifer upstream of the contaminated soil with respect to the flow of groundwater in the aquifer, and injects the chemical solution in the vicinity above the contaminated soil, A chemical solution injection well for immersing in the chemical solution to form a chemical layer, an aquifer water level sensor for measuring the water level of the aquifer, a chemical layer water level sensor for measuring the water level of the chemical layer, and Control means for controlling the injection amount of the chemical liquid so that the water level of the chemical liquid layer is maintained higher than the water level of the aquifer based on the measurement values of the aquifer water level sensor and the chemical liquid layer water level sensor And characterized by comprising
[0019]
According to claim 4, with respect to the contaminated soil existing in the aquifer, there is a height that reaches the lowest level of the aquifer upstream of the contaminated soil with respect to the groundwater flow in the aquifer. By providing a water-permeable partition, it is possible to prevent the groundwater of the aquifer from flowing into the contaminated soil.
[0020]
In addition, by providing a chemical solution injection well that injects chemical solution into the contaminated soil from above the contaminated soil, the loam layer easily penetrates vertically, so that the chemical solution penetrates the soil in a short time, Since the chemical solution layer immersed in the vertical direction without being diffused can be formed, the contaminated soil can be effectively purified in a short time. In addition, since it is possible to suppress the chemical solution from coming into contact with other soil and reacting with the components in the other soil as much as possible, the amount of the chemical solution used for the purification of the contaminated soil can be greatly reduced.
[0021]
Furthermore, by providing an aquifer water level sensor and a chemical liquid layer level sensor for measuring each water level in the aquifer and chemical liquid layer, the water levels of the aquifer and chemical liquid layer can always be measured. Then, based on the measured values in the aquifer water level sensor and the chemical liquid level sensor, the amount of the chemical to be injected is controlled by the control means so that the water level of the chemical liquid layer is always kept higher than the water level of the aquifer. Thus, since the inflow of groundwater from the aquifer to the chemical solution layer due to the difference in water level can be prevented, the contaminated soil can be stably purified by the chemical solution.
[0022]
A fifth aspect of the present invention is characterized in that, in the fourth aspect, the water supply well for pumping water upstream of the partition and a water injection well for pouring water downstream of the contaminated soil.
[0023]
According to claim 5, the groundwater in the upstream aquifer is pumped from the pumping well provided upstream from the partition wall, and the groundwater is injected into the water injection well provided downstream from the contaminated soil. Therefore, the groundwater in the aquifer can flow from the pumping well to the water injection well without passing through the contaminated soil. Can be reliably prevented from reaching the contaminated soil and being contaminated. Therefore, even if the water level of the upstream aquifer increases due to environmental changes such as heavy rain and groundwater flow, the relationship between the water level of the aquifer and the chemical layer can always be maintained stably, so it is more stable. It is possible to purify contaminated soil with chemicals.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a soil purification method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0025]
FIG. 1 is a cross-sectional view showing a schematic configuration of a soil purification apparatus 10 according to a first embodiment of the present invention, which is an example in which a partition wall and a chemical solution injection well are provided.
[0026]
As shown in FIG. 1, the loam layer 12 is formed mainly by depositing highly permeable soil such as weathered volcanic ash, and impermeable soil such as clay is deposited thereunder. Layer 18 is formed. Water such as rain enters the loam layer 12 and accumulates on top of the impermeable layer 18, thereby forming the aquifer 14. The contaminated soil 16 is formed at substantially the same depth as the aquifer 14 when the contaminants enter and remain in a part of the loam layer 12.
[0027]
The soil purification apparatus 10 mainly includes a partition wall 20, a chemical solution injection well 22, a chemical solution tank 24, a chemical solution injection pipe 26, a chemical solution injection pump 28, and a control device 36.
[0028]
The partition wall 20 is made of a water-impermeable material, is located upstream of the contaminated soil 16 with respect to the direction of groundwater flow in the aquifer 14, and has a height from the ground surface to the water-impermeable layer 18. Have. The width of the partition wall 20 is preferably a width that can prevent the groundwater of the aquifer 14 from flowing into the contaminated soil 16.
[0029]
The chemical injection well 22 is formed by excavating the loam layer 12 from the ground surface to the vicinity of the upper part of the contaminated soil 16. The ground surface is provided with a chemical tank 24 for storing a chemical liquid to be injected from the chemical injection well 22 into the contaminated soil 16. The chemical injection well 22 and the chemical tank 24 are connected by a chemical injection pipe 26. The chemical solution injection pipe 26 is provided with a chemical solution injection pump 28. By driving the chemical solution injection pump 28, the chemical solution stored in the chemical solution tank 24 is contaminated via the chemical solution injection pipe 26 and the chemical solution injection well 22. It is injected into. The chemical injection well 22 preferably has a structure capable of effectively immersing the chemical in the contaminated soil 16.
[0030]
As the chemical solution, a substance that can be chemically decomposed and purified, such as an oxidant and a reducing agent, that is, can be purified by chemical decomposition, and it is preferable to use a solution that is easy to inject. The chemical solution is not limited to a substance that chemically decomposes the pollutant in the contaminated soil 16, and the injected microorganism is injected with a solution containing microorganisms or nutrient salts having a resolution of the pollutant as the chemical solution. Alternatively, the pollutants in the contaminated soil 16 may be decomposed by increasing the activity of microorganisms present in the soil.
[0031]
Thus, the chemical solution layer 30 is formed by injecting the chemical solution from the chemical injection well 22 into the contaminated soil 16 and immersing it. The chemical liquid layer 30 is provided with a chemical liquid layer water level sensor 32 to measure the groundwater level in the chemical liquid layer 30. As the chemical water level sensor 32, it is preferable to use a throw-in type water level sensor capable of measuring the groundwater level by pressure, while the aquifer water level sensor 34 is provided in the aquifer 14 upstream of the partition wall 20. It is done. As the aquifer water level sensor 34, it is preferable to use a throwing water level sensor that can measure the groundwater level by pressure.
[0032]
The chemical water level sensor 32 and the aquifer water level sensor 34 are connected to a control device 36 that is a control means provided on the ground surface, and the water level measured by the chemical water level sensor 32 and the aquifer water level sensor 34 is measured. A value is sent. The control device 36 is also connected to the chemical solution injection pump 28, and the control device 36 controls the driving of the chemical solution injection pump 28 based on the measured value.
[0033]
Next, the effect | action in the soil purification apparatus 10 which is the 1st Embodiment of this invention mentioned above is demonstrated.
[0034]
By providing the partition wall 20 as the soil purification device 10, the groundwater in the aquifer 14 can be prevented from flowing into the contaminated soil 16. As a result, it is possible to prevent the contaminants from being eluted from the contaminated soil 16 and contaminating the groundwater, thereby effectively preventing the contamination of the soil by spreading the contaminants by the contaminated groundwater. can do.
[0035]
Further, by providing the chemical solution injection well 22 so that the chemical solution is injected from above the contaminated soil 16, the contaminated soil 16 can be reliably purified. This is because the loam layer 12 formed of loam or the like that is an aeolian layer has a characteristic that water permeability is higher in the vertical direction than in the horizontal direction, and it is easy to pass water. Therefore, by injecting the chemical solution from the vertical direction, the chemical solution can be permeated into the contaminated soil 16 in a shorter time, so that the time required for the purification of the contaminated soil 16 can be greatly reduced.
[0036]
In addition, when the chemical solution is injected, if the chemical solution comes into contact with uncontaminated soil, the chemical solution may react with the components of the uncontaminated soil. Then, since the effectiveness of the chemical solution decreases before reaching the contaminated soil 16, it is necessary to inject more than the amount necessary for decomposing the contaminant contained in the contaminated soil 16. Therefore, the chemical solution injection well 22 is extended to the vicinity of the upper part of the contaminated soil 16 and injected from the vicinity of the upper part of the contaminated soil 16 so that the injected chemical liquid is directly injected into the contaminated soil 16 and is not contaminated. The amount of chemicals consumed in contact with soil can be minimized. Therefore, since the amount of chemicals injected into the contaminated soil 16 can be reduced, the cost required for purification of the contaminated soil 16 can be reduced.
[0037]
By the way, when water exists in the soil, the water tends to flow from a higher water level and a lower water pressure to a lower water pressure. Therefore, when the water level of the chemical liquid layer 30 is lower than the water level of the aquifer 14 blocked by the partition wall 20, the flow of groundwater in the blocked aquifer 14 may be directed toward the chemical liquid layer 30. There is. If it does so, groundwater may flow in the direction which flows in the chemical | medical solution layer 30 around the partition 20, or groundwater may flow into the chemical solution layer 30 from the upper part of the partition 20, or a clearance gap. If groundwater flows into the chemical solution layer 30, the chemical solution is diluted, so that not only the contaminated soil 16 cannot be reliably purified, but also the contaminants of the contaminated soil 16 that could not be purified are eluted into the groundwater. In addition, the groundwater in the aquifer 14 is contaminated, and the contaminated groundwater flow may cause an increase in soil contamination.
[0038]
Therefore, the water levels of the chemical layer 30 and the aquifer 14 are always measured by the chemical layer water level sensor 32 and the aquifer water level sensor 34, and control is performed based on the measured values of the chemical layer water level sensor 32 and the aquifer water level sensor 34. By controlling the drive of the chemical solution injection pump 28 with the device 36 and adjusting the amount of the chemical solution to be injected so that the water level of the chemical solution layer 30 is always higher than the water level of the aquifer 14, the inflow of groundwater due to the water level difference is ensured. Can be prevented. Thereby, the contaminated soil 16 can be stably purified with the chemical solution. Since an appropriate amount of the chemical solution is injected into the contaminated soil 16 and the waste of the chemical solution can be reduced, the cost required for the purification of the contaminated soil 16 can be reduced.
[0039]
FIG. 2 is a cross-sectional view of a soil purification apparatus 50 according to the second embodiment of the present invention, in which an inverted L-shaped chemical solution injection well, a pumping well, and a water injection well are provided. It is.
[0040]
As shown in FIG. 2, the configuration of the soil purification apparatus 50 is the same as that of the soil purification apparatus 10 shown in FIG. 1, but a chemical injection well 22 having an inverted L shape and a pump for pumping up groundwater. A well 38 and a water injection well 40 for injecting the pumped ground water are provided.
[0041]
The chemical injection well 22 includes a vertical portion 22 a formed by excavating the contaminated soil 16 in the vertical direction, and a horizontal portion 22 b formed by excavating the upper vicinity of the contaminated soil 16 in the horizontal direction. Composed. The shape of the inverted L time shape is not particularly limited, and includes a vertical portion 22a that supplies the chemical solution from the ground surface to the upper vicinity of the contaminated soil 16 and a horizontal portion 22b that injects the chemical solution to the contaminated soil 16. What is necessary is just to be comprised, and L shape and reverse T-shape may be sufficient. By driving the chemical injection pump 28 provided on the ground surface, the chemical stored in the chemical tank 24 passes through the vertical portion 22a of the chemical injection well 22 through the chemical injection pipe 26 and passes through the chemical injection well 22. To the horizontal portion 22b. Then, a chemical | medical solution is inject | poured with respect to the upper vicinity of the contaminated soil 16 from many holes (not shown) provided in the horizontal part 22b.
[0042]
The pumping well 38 is provided upstream of the partition wall 20 with respect to the flow of groundwater in the aquifer 14, and is formed by excavating the loam layer 12 until reaching the aquifer 14.
[0043]
Further, the water injection well 40 is provided downstream of the contaminated soil 16 with respect to the groundwater flow in the aquifer 14, and the water injection well 40 is injected at a position lower than the chemical liquid layer 30. It is formed by excavating to a position deeper than 30.
[0044]
The pumping well 38 and the water injection well 40 are connected by a connecting pipe 42. A pumping pump 44 is provided at the pumping side of the connecting pipe 42, that is, at the bottom of the pumping well 38, and the groundwater in the aquifer 14 is pumped by driving the pumping pump 44, and the water injection well is connected via the connecting pipe 42. Water is sent to 40. By pumping the supplied groundwater to the bottom of the water injection well 40, the pumped groundwater merges with the downstream aquifer 46.
[0045]
The downstream aquifer 46 is provided with a downstream aquifer water level sensor 48. As the downstream aquifer water level sensor 48, it is preferable to use a throw-in water level sensor that can measure the groundwater level by pressure. The downstream aquifer water level sensor 48 is connected to the control device 36, and the measurement value of the downstream aquifer water level sensor 48 is transmitted to the control device 36.
[0046]
The pumping pump 44 is also connected to the control device 36, and the driving of the pumping pump 44 is controlled by the control device 36 based on each measured value.
[0047]
Next, the effect | action in the soil purification apparatus 50 which is the 2nd Embodiment of this invention mentioned above is demonstrated.
[0048]
The chemical injection well 22 is provided with a horizontal portion 22b that is horizontal with respect to the vicinity of the upper side of the contaminated soil 16, and the chemical solution is injected from a large number of holes arranged in the horizontal direction of the horizontal portion 22b. More efficient chemical injection can be performed on the soil 16. Thereby, while the time which purification | cleaning of the contaminated soil 16 can be shortened further, the chemical | medical solution layer 30 with the high water level which does not spread in a horizontal direction can be formed.
[0049]
Further, by forming a groundwater flow path in the aquifer 14 to be joined to the downstream aquifer 46 through the pumping well 38, the connecting pipe 42, and the water injection well 40, the groundwater gives priority to this flow path. Therefore, the inflow of groundwater into the chemical solution layer 30 and the contaminated soil 16 can be more reliably prevented. Therefore, even if the amount of groundwater in the aquifer 14 increases due to environmental changes such as heavy rain or groundwater confluence, the groundwater is pumped from the aquifer 14 and injected into the downstream aquifer 46. Therefore, the contaminated soil 16 can be purified with a chemical solution more stably.
[0050]
Further, the downstream aquifer 46 is provided with a downstream aquifer water level sensor 48 connected to the control device 36, and the pumping pump 44 is also connected to the control device 36. The water level of the layer 30 and the downstream aquifer 46 can be adjusted. That is, when the water level of the aquifer 14 rises, the control device is configured to lower the water level of the aquifer 14 and keep the water level of the chemical solution layer 30 higher than the water levels of the aquifer 14 and the downstream aquifer 46. What is necessary is just to drive the chemical | medical solution injection pump 26 and the pumping pump 44 by 36. Further, when the water level of the aquifer 14 is lowered, the control device 36 injects a chemical solution so that the water level of the chemical solution layer 30 can be maintained higher than that of the aquifer 14 and the downstream aquifer 46. What is necessary is just to drive the chemical injection pump 28 and stop the pumping pump 44 so as to reduce the amount of the chemical to be injected. Furthermore, when the water level of the aquifer 14 and the downstream aquifer 46 rises, the amount of the chemical solution that can maintain the water level of the chemical solution layer 30 higher than that of the aquifer 14 and the downstream aquifer 46 is injected. Further, the chemical liquid injection pump 28 is driven by the control device 36 so as to increase the amount of chemical liquid to be injected, and the pumping pump 44 is driven so that the water levels of the aquifer 14 and the downstream aquifer 46 are the same level. You can do it.
[0051]
From these things, in the soil purification apparatus 50, while being able to purify the contaminated soil 16 with a more stable chemical solution in any environment, and to purify the contaminated soil 16 by injecting an appropriate amount of the chemical solution, The cost required for purification can be further reduced.
[0052]
In addition, in the soil purification apparatuses 10 and 50 mentioned above, the number, shape, material, etc. of each member and apparatus are not specifically limited.
[0053]
Even if the chemical solution flows from the chemical solution layer 30 into the aquifer 14 and the downstream aquifer 46 due to the difference in the water level, there is no problem because it is groundwater after being purified by the chemical solution, and the diffusion of contamination due to the inflow of the chemical solution. Does not occur.
[0054]
Further, the groundwater pumped from the pumping well 38 is directly joined to the downstream aquifer 46 through the connecting pipe 42 and the water injection well 40, but is not particularly limited. The water may be discharged at another place that does not flow into the contaminated soil 16. Further, if a pipe for joining a part of the pumped water to the chemical liquid tank 24 is newly provided and mixed with the chemical in the chemical liquid tank 24 and used as a raw material for the chemical liquid, the cost required for the purification of the contaminated soil 16 is further reduced. can do.
[0055]
【The invention's effect】
As described above, in the soil purification method and apparatus according to the present invention, the groundwater flowing from the aquifer to the contaminated soil is shut off, and the chemical solution is injected into the contaminated soil from above to make it more than the aquifer. By forming a chemical layer with a high water level, groundwater in the aquifer can flow into the contaminated soil and effectively prevent the spread of pollutants through the groundwater. Can be effectively injected in time.
[0056]
In addition, by pumping groundwater from the blocked aquifer and pouring the pumped groundwater downstream from the contaminated soil, no groundwater flows from the aquifer to the chemical and contaminated soil in any environment. Therefore, it is possible to purify stable contaminated soil with a chemical solution.
[0057]
By these, the effective purification | cleaning which reduced the time and cost significantly can be performed with respect to the contaminated soil which exists in an aquifer.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a soil purification apparatus according to a first embodiment of the present invention. FIG. 2 illustrates a schematic configuration of a soil purification apparatus according to a second embodiment of the present invention. Sectional view [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10,50 ... Soil purification apparatus, 12 ... Loam layer, 14 ... Aquifer, 16 ... Contaminated soil, 18 ... Impervious layer, 20 ... Bulkhead, 22 ... Well for chemical injection, 22a ... Vertical part, 22b ... Horizontal part , 24 ... Chemical liquid tank, 26 ... Chemical liquid injection pipe, 28 ... Chemical liquid injection pump, 30 ... Chemical liquid layer, 32 ... Chemical liquid layer water level sensor, 34 ... Aquifer water level sensor, 36 ... Control device, 38 ... Well for pumping, 40 ... Wells for water injection, 42 ... Connection piping, 44 ... Pumping pump, 46 ... Downstream aquifer, 48 ... Downstream aquifer water level sensor

Claims (5)

In a soil purification method for treating a pollutant contained in the contaminated soil by injecting a chemical solution to the contaminated soil present in the aquifer,
By blocking the upstream aquifer upstream of the contaminated soil against the flow of groundwater in the aquifer, preventing the inflow of the groundwater into the contaminated soil,
Injecting the chemical solution to the contaminated soil, immersing the contaminated soil with the chemical solution to form a chemical layer,
The soil purification method characterized by maintaining the water level of the chemical solution layer higher than the water level of the upstream aquifer. When the aquifer and contaminated soil are composed of loam layers that are highly permeable to the vertical direction,
The soil purification method according to claim 1, wherein the chemical solution is injected in a vertical direction from above the contaminated soil. Drawing groundwater from the upstream aquifer,
3. The soil purification method according to claim 1 or 2, wherein the soil is purified by pouring into a downstream aquifer downstream from the contaminated soil with respect to a groundwater flow in the aquifer. In a soil purification apparatus for treating pollutants contained in the contaminated soil by injecting chemicals into the contaminated soil present in the aquifer,
An impermeable partition that blocks the upstream aquifer upstream of the contaminated soil with respect to the flow of groundwater in the aquifer,
Injecting the chemical solution near the upper part of the contaminated soil, and immersing the contaminated soil with the chemical solution to form a chemical solution layer,
An aquifer water level sensor for measuring the water level of the aquifer,
A chemical layer water level sensor for measuring the water level of the chemical layer;
Control for controlling the injection amount of the chemical liquid so that the water level of the chemical liquid layer is maintained higher than the water level of the aquifer based on the measurement values of the aquifer water level sensor and the chemical liquid layer water level sensor And a soil purification apparatus. A well for pumping water upstream from the partition;
The soil purification apparatus according to claim 4, further comprising: a water injection well that injects water downstream of the contaminated soil.

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