JP5697415B2 - Purification method for contaminated soil - Google Patents

Description

The present invention relates to method of purifying polluted soil.

  Conventionally, as a method of removing soil contaminated with volatile or non-volatile pollutants in situ, (1) an injection well and a suction well are provided in the ground, and steam is injected from the injection well, while a suction well There is a method of taking out the pollutant by performing suction (for example, see Patent Document 1).

  In addition, (2) there was a method of injecting a purification liquid into the ground and vacuuming groundwater. In the method of (2), for example, an injection well and a drain pipe are provided on the ground, a purification liquid is injected into the injection well, and groundwater is sucked through the drain pipe (see, for example, Patent Document 2). .

Japanese Patent No. 4042969 JP 2007-260610 A

  However, when removing pollutants held on the ground with low water permeability such as clayey soil, the method (1) has a problem that groundwater suction speed is slow and it takes time to remove pollutants. . The method (2) solves this problem, but it takes a lot of time and money to form a plurality of wells when the area containing the contaminant is extensive.

The present invention has been made in view of the above problems, it is an object of the present invention, readily switch the the pumping position and the injection position depending on the situation, efficiently polluted soil which contaminants can be removed it is to provide a method of purifying.

To achieve the above object, the present invention provides a method of purifying contaminated soil in situ, the contaminated soil, the contamination of the switchable plurality of drain material alone and for water injection and for pumping and step (a) to embed the entire soil, the the plurality of drain material, set each of the number of drain material for water injection and for pumping as the pumping amount and the injection amount becomes appropriate balance, A step (b) of setting the positions of the drainage materials for pumping and pouring so as to form a flow in which the unpurified portion is treated , and dividing the materials into pumping and pouring water; A cap having a hose is provided at the upper end of the drain material used for pumping at least among the plurality of drain materials, and a negative pressure is applied using a vacuum pump connected to the drain material for pumping through the cap. Previous While pumping groundwater from the contaminated soil through the pumping drain material, a predetermined fluid is injected into the contaminated soil through the water pouring drain material to form a water circulation flow in the contaminated soil. A step (c) and a step (d) of treating the pumped groundwater in a water treatment facility having a predetermined performance, wherein the drain material is a paper drain or a plastic drain, After the concentration reaches a predetermined standard, the pumping and the water injection are temporarily stopped, and the step (b) to the step (d) are repeated to purify the remaining unpurified portion. This is a soil purification method.

  In the present invention, since the pumping and pouring are performed using the drain material that can be easily placed using a dedicated casting machine, the construction period required for the preparation before the pumping / pouring operation is compared with the case of installing the well. Shortening and cost savings are possible. In addition, since the drainage material can be easily set in the placement depth, it is easy to cope even when the geological structure is complicated. In the present invention, since a negative pressure is generated in the ground due to pumping, a predetermined fluid can be easily injected at a low pressure. In the present invention, if necessary, the drain material is divided again into pumping and pouring water, and step (b) and subsequent steps are repeated a plurality of times.

  In the present invention, for example, caps having hoses are provided at the upper ends of all the plurality of drain members, and each drain member is connected to a valve connected to a vacuum pump and a water supply tank via the caps. Each drain material can be switched between pumping and water injection by switching the flow of a predetermined fluid by a valve.

  In this invention, the cap which has a hose is provided only in the upper end of the drain material used for pumping out of a plurality of drain materials, and the water tank may be provided in the upper end of the drain material used for water injection. In this case, after removing the cap and the water tank, the multiple drainage materials can be switched between pumping and water injection by re-dividing into the water injection and water pumping and providing the cap and water tank. is there.

  By independently switching each drain material between pumping and pouring water, it is possible to easily switch between the pumping position and the pouring position according to the situation of the contaminated soil / groundwater area. By switching between the pumping position and water injection position of the drain material according to the status of the treatment of the pollutant, forming an appropriate water circulation flow and repeating the purification process, the entire contaminated soil and groundwater area can be purified efficiently and reliably. it can. In the present invention, since the water flow can be reversed by switching each drain material between pumping and water injection, clogging of the drain material can be prevented.

  In the step (c), the amount of pumped water and the amount of water injected are monitored by monitoring the amount of groundwater pumped, the amount of water injected into the predetermined fluid, the pressure of the predetermined fluid, the concentration of the pollutant, and the pore water pressure in the contaminated soil / groundwater region. Keep it in proper balance. By maintaining an appropriate balance between the amount of pumped water and the amount of water injected, circulation of groundwater in the contaminated area can be promoted and efficient purification of groundwater can be achieved. Moreover, by performing water injection at the same time as pumping, consolidation of the ground due to negative pressure during pumping can be suppressed.

Drain material, and Bae over par drain or plastic drain. By using a paper drain or a plastic drain, the drain material can be arranged at an arbitrary position in a dense state.

  The drain material is made of, for example, a biodegradable material. By using a biodegradable material, it can be left without draining after draining the soil. Desirably, the predetermined fluid includes at least one cleaning agent of water or an oxidizing agent, a microbial activator, and a reducing agent. By containing these purification agents, groundwater can be efficiently purified.

  In the case of using a fluid containing water or a purifying agent as the predetermined fluid, in step (d), the concentration of the pollutant immediately after pumping of the pumped ground water and the concentration of the pollutant after the water treatment are measured. Manage. By performing such purification management, it is possible to reliably determine the purification effect.

According to the present invention, can be provided easily switch between pumping position and injection position depending on the situation, a method of purifying polluted soil which can efficiently remove contaminants.

Vertical sectional view of groundwater purification system 1 Plan view of groundwater purification system 1 Horizontal sectional view of groundwater purification system 1 The figure which shows other arrangement | positioning of the drain material 7 Vertical sectional view of groundwater purification system 1a The figure which shows the example in case the permeable layer 39 exists in the intermediate part of the contamination area | region 37

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a vertical sectional view of the groundwater purification system 1, and FIG. 2 is a plan view of the groundwater purification system 1. 1 is a cross-sectional view taken along arrow AA shown in FIG.

  As shown in FIG. 1, the groundwater purification system 1 is installed near the contaminated soil / groundwater region 5 of the ground 3. The groundwater purification system 1 includes a seal layer 4, a plurality of drain materials 7, a valve 25, a water injection pipe 23a, a drain pipe 23b, a water supply tank 9, a vacuum pump 27, a water treatment facility 29, and the like.

  As shown in FIG. 2, the drain material 7 is arranged in a staggered pattern in the contaminated soil / groundwater region 5 as viewed in plan. As shown in FIG. 1, the drain material 7 is embedded in the contaminated soil / groundwater region 5 so that the upper end 11 is located on the lower surface of the seal layer 4 provided on the surface of the ground 3. The drain material 7 is, for example, a paper drain or a plastic drain. The drain material 7 is made of, for example, a biodegradable material.

  A cap 17 having a hose 20 is provided at the upper end 11 of all the drain members 7. The cap 17 is assumed to be airtight. The hose 20 is connected to the valve 25.

  A water injection hose 21a and a drain hose 21b are connected to all the valves 25. The water injection hose 21a is a branch pipe of the water injection pipe 23a. The drain hose 21b is a branch pipe of the drain pipe 23b. The water injection pipe 23 a is connected to the water supply tank 9. The drain pipe 23 b is connected to the vacuum pump 27 and the water treatment facility 29.

  Each drain material 7 can be switched for pumping and water injection independently by switching the fluid flow in and out by a valve 25 connected thereto. When the drain material 7 is used as the draining drain material 7a, the flow on the drainage hose 21b side is blocked by the valve 25. When the drain material 7 is used as the drainage drain material 7b, the flow on the water injection hose 21a side is blocked by the valve 25.

  Next, a method for purifying the contaminated soil / groundwater region 5 using the groundwater purification system 1 will be described. In order to purify the contaminated soil / groundwater region 5, first, a plurality of drain materials 7 are buried in the contaminated soil / groundwater region 5 to construct the groundwater purification system 1. And the several drain material 7 is divided into the drain material 7a for water injection, and the drain material 7b for pumping. The water draining material 7a and the pumping water draining material 7b are alternately arranged in a line as shown in FIG.

  Next, negative pressure is applied to the contaminated soil / groundwater region 5 by pumping using the vacuum pump 27, and groundwater is discharged from the contaminated soil / groundwater region 5 through the drainage drain material 7b, the drainage hose 21b, and the drainage pipe 23b. Pump up the water. At the same time, a predetermined fluid is poured into the contaminated soil / groundwater region 5 from the water tank 9 through the water injection pipe 23a, the water injection hose 21b, and the water injection drain material 7a, and a plurality of water circulation flows into the contaminated soil / groundwater region 5 Form. The flow of water circulation can be confirmed, for example, by collecting a tracer mixed with a predetermined fluid on the injection side on the pumping side.

  In the groundwater purification system 1, the amount of groundwater pumped, the concentration of contaminants, the amount of water injected into a predetermined fluid, the pressure of the predetermined fluid, and the pore water pressure in the contaminated soil / groundwater region 5 are monitored. Thereby, the amount of pumped water from the drainage drain material 7b and the amount of water poured from the drainage drain material 7a in the contaminated soil / groundwater region 5 are kept in an appropriate balance. The monitoring is performed using, for example, a predetermined sensor (not shown) provided at the tip 13 of the drain material 7.

  The pumped ground water is treated in a water treatment facility 29 having a predetermined performance. The predetermined fluid includes at least one cleaning agent among water or an oxidizing agent, a microbial activator, and a reducing agent. In the groundwater purification system 1, the purification is managed by measuring the concentration of pollutants immediately after pumping up the groundwater and the concentration of contaminants after water treatment.

  In the groundwater purification system 1, for example, after the concentration of the pollutant after pumping satisfies a predetermined standard, pumping using the vacuum pump 27 and water injection from the water supply tank 9 are temporarily stopped. Then, according to the situation of the contaminated soil / groundwater region 5, the plurality of drain materials 7 are again divided into the water injection drain material 7a and the pumping drain material 7b, and the valve 25 of the drain material 7 whose classification is changed is switched. Thereafter, pumping using the vacuum pump 27 and water injection from the water supply tank 9 are performed again, and the pumped ground water is treated in the water treatment facility 29.

  When purifying the contaminated soil / groundwater region 5, the drain material 7 is divided, pumped using the vacuum pump 27, injected from the water tank 9, and the pumped groundwater treatment is repeated as necessary.

  When the drain material 7 is divided, the numbers of the water injection drain material 7a and the pumping water drain material 7b are set so that the pumped water amount and the water injection amount are in an appropriate balance. Further, the positions of the water injection drain material 7a and the pumping water drain material 7b are such that the flow of the water circulation is appropriately formed according to the progress of the processing of the pollutant, that is, the unpurified portion is processed. Set so that a flow is formed. As described above, each drain member 7 can be switched for pumping and water injection independently by switching the valve 25 connected thereto. In the groundwater purification system 1, the drain material 7 can be locally switched between pumping and water injection.

  Thus, according to the first embodiment, in order to perform pumping and water injection using the drain material 7 that can be easily placed using a dedicated placing machine, compared to the case of installing a well, It is possible to shorten the construction period and cost required for preparation before pumping and water injection work. Moreover, since the drainage material 7 can easily set the placement depth, it is easy to cope with a complicated structure of the contaminated soil / groundwater region 5.

  In the first embodiment, since negative pressure is generated in the contaminated soil / groundwater region 5 by pumping, a predetermined fluid can be easily injected at a low pressure. In addition, by switching each drain member 7 between pumping and pouring by the valve 25, the pumping position and the pouring position can be easily switched according to the situation of the contaminated soil / groundwater region 5. Purify efficiently over the entire contaminated soil / groundwater area 5 by switching the pumping position and water injection position of the drain material 7 according to the processing status of the pollutant, forming an appropriate water circulation flow and repeating the purification process. it can. For example, even if there is a part with poor water permeability between the pumping position and the water injection position during the first purification process and there remains an unpurified part, the running water will proceed so that the unpurified part will proceed during the next process. Since purification can be performed by changing the direction, purification can be performed reliably. In the first embodiment, since the water flow can be reversed by switching each drain material 7 between pumping and water injection, clogging of the drain material 7 can be prevented.

  In the first embodiment, the amount of groundwater pumped, the amount of water injected into the predetermined fluid, the pressure of the predetermined fluid, the concentration of pollutants, the pore water pressure in the contaminated soil / groundwater region 5 are monitored, and the amount of pumped water and the amount of water injected are Maintain proper balance. Thereby, circulation of groundwater in a pollution field can be promoted and groundwater can be efficiently purified. In addition, by performing water injection simultaneously with pumping, unnecessary compaction of the soil layer due to negative pressure during pumping can be suppressed.

  In the first embodiment, the drain material 7 is a paper drain or a plastic drain, so that the drain material 7 can be arranged at an arbitrary position in a dense state. By arranging the drain material 7 finely in a plane, groundwater can be purified efficiently even when the hydraulic conductivity of the contaminated soil / groundwater region 5 is small. Further, by using a biodegradable material for the drain material 7, it can be left without removing the drain material 7 after the soil is purified.

  In the first embodiment, groundwater can be efficiently purified by pouring a fluid containing at least one purification agent among water or an oxidizing agent, a microbial activator, and a reducing agent into the contaminated soil / groundwater region 5. Further, by measuring the concentration of the pollutant immediately after pumping up the groundwater and the concentration of the pollutant after water treatment, and managing the purification, the effect of the purification can be determined reliably.

  In the first embodiment, when the purification of the contaminated soil / groundwater region 5 is started, as shown in FIG. 2, the drainage material 7a and the drainage material 7b are alternately arranged in a line. However, the arrangement of the water injection drain material 7a and the pumping water drain material 7b at the start of purification is not limited to this. In the groundwater purification system 1, the drainage material 7a and the drainage material 7b are locally arranged or switched so that the amount of pumped water and the amount of water injected are in an appropriate balance and the flow of water circulation is properly formed. It is possible to

  FIG. 3 shows a horizontal sectional view of the groundwater purification system 1. As shown in FIG. 3, in the groundwater purification system 1, for example, one drain member 7 is used as a pumping drain member 7b, and the rest is used as a water injection drain member 7a, while sequentially changing the position of the pumping drain material 7b, You may repeat the pumping using the vacuum pump 27, the water injection from the water supply tank 9, and the processing of the pumped-up groundwater.

  In the first embodiment, the plurality of drain members 7 are arranged in a staggered manner, but the arrangement of the drain members 7 is not limited to this. FIG. 4 is a diagram showing another arrangement of the drain material 7. As shown in FIG. 4, a plurality of drain materials 7 may be arranged in a lattice shape. What is necessary is just to determine the arrangement | positioning of the drain material 7 according to the condition of the contamination of the contaminated soil and groundwater area 5. In the first embodiment, water is supplied to the drain material 7 using the water supply tank 9, but a water supply pump or a water injection pump may be used in addition to the water supply tank.

  Next, a second embodiment will be described. FIG. 5 shows a vertical sectional view of the groundwater purification system 1a. 5A is a vertical cross-sectional view at a position including the water injection drain material 7a, and FIG. 5B is a vertical cross-sectional view at a position including the pumping drain material 7b.

  As shown in FIG. 5, the groundwater purification system 1 a is installed in the vicinity of the contaminated soil / groundwater region 5 of the ground 3 in the same manner as the groundwater purification system 1 of the first embodiment. The groundwater purification system 1a includes a seal layer 4, a plurality of drain materials 7, a drain pipe 19, a submerged tank 15, a vacuum pump 27, a water treatment facility 29, and the like. In the groundwater purification system 1a, for example, a plurality of drain materials 7 are arranged in a staggered pattern in a contaminated soil / groundwater region 5 when viewed in plan.

  As shown in FIG. 5, the drain material 7 is embedded in the contaminated soil / groundwater region 5 so that the upper end 11 is located on the upper surface of the contaminated region below the seal layer 4 provided on the surface of the ground 3. The drain material 7 is, for example, a paper drain or a plastic drain. The drain material 7 is made of, for example, a biodegradable material.

  As shown in FIG. 5 (a), a water tank 15 is installed at the upper end 11 of the water injection drain member 7a via a water injection hose 22a and a valve 24. The valve 24 switches between start and stop of water injection from the submerged tank 15 to the water injection hose 22a. As shown in FIG. 5B, a cap 17 having a drain hose 22b is provided at the upper end 11 of the drainage drain material 7b. The cap 17 is assumed to be airtight. The drain hose 22 b is connected to the drain pipe 19. The drain pipe 19 is connected to the vacuum pump 27 and the water treatment facility 29.

  Each drain material 7 can be switched between pumping and water injection independently by removing the water tank 15 and the cap 17 and moving them.

  Next, a method for purifying the contaminated soil / groundwater region 5 using the groundwater purification system 1a will be described. In order to purify the contaminated soil / groundwater region 5, first, a plurality of drain materials 7 are buried in the contaminated soil / groundwater region 5 to construct the groundwater purification system 1a. And the several drain material 7 is divided into the drain material 7a for water injection, and the drain material 7b for pumping. The water injection drain material 7a and the pumping water drain material 7b are alternately arranged, for example, one row at a time.

  Next, negative pressure is applied to the contaminated soil / groundwater region 5 by pumping using the vacuum pump 27, and groundwater is discharged from the contaminated soil / groundwater region 5 through the drainage drain material 7 b, the drainage hose 22 b, and the drainage pipe 19. Pump up the water. At the same time, a predetermined fluid is poured into the contaminated soil / groundwater region 5 from the water tank 15 through the valve 24, the water injection hose 22a, and the water draining material 7a, and a plurality of water circulation flows are introduced into the contaminated soil / groundwater region 5. Form. The flow of water circulation can be confirmed, for example, by collecting a tracer mixed with a predetermined fluid on the injection side on the pumping side.

  In the groundwater purification system 1a, the amount of groundwater pumped, the amount of water injected into the predetermined fluid, the pressure of the predetermined fluid, the concentration of contaminants, and the pore water pressure in the contaminated soil / groundwater region 5 are monitored. Thereby, the amount of pumping from the draining material 7b for pumping and the amount of pouring from the draining material 7a for pouring are kept in an appropriate balance. The monitoring is performed using, for example, a predetermined sensor (not shown) provided at the tip 13 of the drain material 7.

  The pumped ground water is treated in a water treatment facility 29 having a predetermined performance. The predetermined fluid includes at least one cleaning agent among water or an oxidizing agent, a microbial activator, and a reducing agent. In the groundwater purification system 1a, purification is managed by measuring the concentration of pollutants immediately after pumping up the groundwater and the concentration of contaminants after water treatment.

  In the groundwater purification system 1a, for example, after the water quality after water treatment and the concentration of contaminants satisfy predetermined standards, the pumping using the vacuum pump 27 and the water injection from the submerged tank 15 are temporarily stopped. Then, after removing the water tank 15 and the cap 17 from the drain material 7 and re-dividing the drain material 7 into the water injection drain material 7a and the pumping drain material 7b according to the situation of the contaminated soil / groundwater region 5, The submerged tank 15 and the cap 17 are moved as appropriate. Thereafter, pumping using the vacuum pump 27 and water injection from the submerged tank 15 are performed again, and the groundwater thus pumped is treated in the water treatment facility 29.

  When the contaminated soil / groundwater region 5 is purified, the drain material 7 is divided, pumped using the vacuum pump 27, injected from the submerged tank 15, and the pumped groundwater is repeated as necessary.

  When the drain material 7 is divided, the numbers of the water injection drain material 7a and the pumping water drain material 7b are set so that the pumped water amount and the water injection amount are in an appropriate balance. Further, the positions of the water injection drain material 7a and the pumping water drain material 7b are such that the flow of the water circulation is appropriately formed according to the progress of the processing of the pollutant, that is, the unpurified portion is processed. Set so that a flow is formed. As described above, each drain member 7 can be switched between pumping and pouring independently by removing and transferring the submerged tank 15, the cap 17, and the like. In the groundwater purification system 1a, the drain material 7 can be locally switched between pumping and water injection.

  Thus, in the second embodiment as well, in the same way as in the first embodiment, water is pumped and poured using the drain material 7 that can be easily placed using a dedicated placement machine. Compared to the case of installing, it is possible to shorten the construction period and cost required for preparation before pumping and water injection work. Moreover, since the drainage material 7 can easily set the placement depth, it is easy to cope with a complicated structure of the contaminated soil / groundwater region 5.

  Also in the second embodiment, since a negative pressure is generated in the contaminated soil / groundwater region 5 by pumping, a predetermined fluid can be easily injected at a low pressure. In addition, the water tank 9 and the cap 17 are removed and moved, and each drain material 7 is switched between pumping and pouring water, so that the pumping position and pouring position can be easily set according to the situation of the contaminated soil / groundwater region 5. You can switch to Purify efficiently over the entire contaminated soil / groundwater area 5 by switching the pumping position and water injection position of the drain material 7 according to the processing status of the pollutant, forming an appropriate water circulation flow and repeating the purification process. it can. For example, even if there is a part with poor water permeability between the pumping position and the water injection position during the first purification process and there remains an unpurified part, the running water will proceed so that the unpurified part will proceed during the next process. Since purification can be performed by changing the direction, purification can be performed reliably. In the second embodiment, since the water flow can be reversed by switching each drain material 7 between pumping and water injection, clogging of the drain material 7 can be prevented.

  Also in the second embodiment, the amount of groundwater pumped, the amount of water injected into the predetermined fluid, the pressure of the predetermined fluid, the concentration of the pollutant, the pore water pressure in the contaminated soil / groundwater region 5 are monitored, and the amount of water pumped and injected And keep it in proper balance. Thereby, circulation of groundwater in a pollution field can be promoted and groundwater can be efficiently purified. In addition, by performing water injection simultaneously with pumping, unnecessary compaction of the soil layer due to negative pressure during pumping can be suppressed.

  Also in the second embodiment, by using the drain material 7 as a paper drain or a plastic drain, the drain material 7 can be arranged at an arbitrary position in a dense state. By arranging the drain material 7 finely in a plane, groundwater can be purified efficiently even when the hydraulic conductivity of the contaminated soil / groundwater region 5 is small. Further, by using a biodegradable material for the drain material 7, it can be left without removing the drain material 7 after the soil is purified.

  Also in the second embodiment, groundwater can be efficiently purified by pouring water containing at least one purification agent among water or an oxidizing agent, a microbial activator, and a reducing agent into the contaminated soil / groundwater region 5. . Further, by measuring the concentration of the pollutant immediately after pumping up the groundwater and the concentration of the pollutant after water treatment, and managing the purification, the effect of the purification can be determined reliably.

  In the second embodiment, when the purification of the contaminated soil / groundwater region 5 is started, the water injection drain material 7a and the pumping drain material 7b are alternately arranged one by one. Similarly to the embodiment, the arrangement of the water injection drain material 7a and the pumping water drain material 7b at the start of purification is not limited to this. In the groundwater purification system 1a, the drainage material 7a and the drainage material 7b are locally arranged or switched so that the amount of pumped water and the amount of water injected are in an appropriate balance and the flow of water circulation is appropriately formed. It is possible to

  In the groundwater purification system 1a, for example, one drain member 7 is used as a pumping drain member 7b, the rest is used as a water injection drain member 7a, and pumping is performed using the vacuum pump 27 while sequentially changing the position of the pumping drain material 7b. The pumping of the water tank 15 and the injected groundwater may be repeated. Further, the planar arrangement of the drain material 7 is not limited to a staggered pattern, and may be determined according to the state of contamination of the contaminated soil / groundwater region 5.

  The first and second embodiments can also be applied to the case where there is a water permeable layer in the upper part or middle part of the contaminated soil / groundwater area 5. FIG. 6 is a diagram illustrating an example in the case where there is a water permeable layer 39 in the middle part of the contaminated region 37. As shown in FIG. 6, when there is a water permeable layer 39 in the contaminated soil / groundwater region 5, a water impermeable process 43 is applied to the outer peripheral surface 41 of the drain material 7. Thereby, a negative pressure can be applied efficiently.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs.

1 ......... Groundwater purification system 5 ......... Contaminated soil / groundwater area 7 ......... Drain material 7a ...... Drain material for water injection 7b ......... Drain material for pumping water 9 ......... Water tank 11 ......... Top 15 ……… Water tank 17 ……… Cap 19, 23b ……… Drain pipe 20 ……… Hose 23a ……… Water injection pipe 25 ……… Valve 27 ……… Vacuum pump 29 ……… Water treatment facility 41 …… ... Outer peripheral surface 43 ...... Impermeable processing

Claims (5)

A method for purifying contaminated soil in situ,
A step (a) of burying a plurality of drain materials that can be switched independently for pumping and water injection in the contaminated soil ;
For the plurality of drainage materials, the number of drainage materials for pumping and watering is set so that the amount of pumped water and the amount of water injected are in an appropriate balance, and the unpurified portion is processed. A step (b) for setting the positions of the drainage materials for pumping and pouring so as to form water and dividing the materials into pumping and pouring water,
A cap having a hose is provided at the upper end of the drain material used for pumping at least among the plurality of drain materials, and a negative pressure is applied using a vacuum pump connected to the drain material for pumping through the cap. While pumping groundwater from the contaminated soil through the drainage drain material, a predetermined fluid is injected into the contaminated soil through the drainage drain material to form a water circulation flow in the contaminated soil. Step (c) to perform,
A step (d) of treating the pumped groundwater in a water treatment facility having a predetermined performance;
Comprising
The drain material is a paper drain or a plastic drain;
After the concentration of the pollutant after pumping meets a predetermined standard, the pumping and water injection are temporarily stopped, and the steps (b) to (d) are repeated to purify the remaining unpurified portion. A method for purifying contaminated soil, characterized in that All the plurality of drain materials are connected to the valve connected to the vacuum pump and the water tank through the cap provided on the drain material upper end,
2. The method for purifying contaminated soil according to claim 1, wherein the plurality of drain materials can be switched between pumping and water injection by switching the predetermined fluid in and out by the valve.   The plurality of drain materials are pumped after removing the cap provided at the upper end of the drain material used for pumping and the flood tank installed at the upper end of the drain material used for water injection. 2. The method for purifying contaminated soil according to claim 1, wherein it is possible to switch between pumping and water injection by re-dividing the water supply and water injection and relocating the cap and the water tank.   By monitoring the pumping amount of the groundwater, the water injection amount of the predetermined fluid, the pressure of the predetermined fluid, the concentration of the pollutant, and the pore water pressure of the contaminated soil, the pumped water amount and the water injection amount are balanced appropriately. The method for purifying contaminated soil according to any one of claims 1 to 3, wherein the method is maintained.   The method for purifying contaminated soil according to any one of claims 1 to 4, wherein the predetermined fluid includes at least one purification agent among water or an oxidizing agent, a microbial activator, and a reducing agent.

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