JP2009112933A - Soil purifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a method of purifying soil contaminated with organic substances such as heavy oils in a short time while preventing a decrease in cleanup efficiency. <P>SOLUTION: The soil purifying method comprises a process of providing a plurality of injection wells and pumping wells arranged among them in contaminated areas containing the soil contaminated by the organic substances so as to reach respectively a lower part than a groundwater level, a process of injecting a soil decontaminating agent from the injection well and pumping up water from the pumping well, and a process of maintaining and improving water passing properties of the soil. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for purifying soil contaminated with organic matter, particularly oil, in situ. In the present invention, the “method for purifying in situ” means a method for purifying the soil without digging up contaminated soil in the ground.

Soil pollution caused by various pollutants caused by industrial activities has become a problem, and the Soil Contamination Countermeasures Law was enacted in February 2003 due to concerns about health effects.
However, the Soil Contamination Countermeasures Law regulates benzene, but not soil contamination by other petroleum. Soil with an oil film or oily odor caused by petroleum is often recognized as contaminated soil for the preservation of the living environment, and in this case, purification is indispensable. In addition, the “Oil Pollution Countermeasure Guidelines” was issued in April 2006 by the Ministry of the Environment regarding countermeasures against oil-contaminated soil originating from oil slicks and oily odors.

  As a technique for purifying soil contaminated with organic substances such as petroleum, for example, there is a method of purifying contaminated soil with a soil purifier containing a surfactant (see, for example, Patent Documents 1 to 3 below). A soil purification agent containing a surfactant has high diffusibility when injected into the ground, and can effectively purify pollutants over a wide range even with a small amount of use.

JP 2003-164844 A JP 2005-279423 A JP 2007-83169 A

  By the way, in the methods described in Patent Documents 1 to 3, the present inventors peel and separate organic substances adhering to soil particles of contaminated soil by a soil purifier containing a surfactant, but they are targeted for purification. In the case where the organic matter is petroleum such as C heavy oil, it has been found that there is a problem that the separated and separated organic matter is clogged in the gaps between the soil particles, making further purification difficult.

  An object of the present invention is to improve the above-mentioned problems, and in particular, while effectively preventing the reduction of the purification efficiency that occurs as the work progresses in-situ purification of contaminated soil using a soil purification agent. It is to provide a way to do.

  The present invention provides a step of providing a plurality of injection wells and pumping wells disposed between them in a contaminated area including soil contaminated with organic matter so as to reach below the groundwater surface, and injecting a soil purification agent from the injection wells And a soil purification method characterized by having a step of pumping water from a pumping well and a step of maintaining and improving the water permeability of the soil. According to the method of the present invention, even when the organic substance peeled and separated from the soil particles by the soil purifier is a petroleum having a high viscosity such as C heavy oil, it has a water permeability maintenance improving process, so that the water permeability of the soil is secured. It is possible to easily recover groundwater containing separated and separated organic substances.

  The step of maintaining and improving the water permeability of the soil used in the soil purification method of the present invention prevents a decrease in the water permeability of the soil due to the organic matter separated (including separation accompanied by decomposition) by the used soil purification agent. The following means are preferably used.

  A first example of the water permeability maintenance improving process suitable for use in the present invention is a process of applying vibration to a contaminated area by a vibrating body. According to this step, vibration is imparted to the organic matter adhering to the soil particles, so that the separation and separation of the organic matter and the mobility of the separated and separated organic matter are maintained and improved, and the recovery efficiency of the organic matter is improved. .

  A second example of the water permeability maintenance improving process suitable for use in the present invention is a process of applying a constant or intermittent pressure to the soil cleaning agent when the soil cleaning agent is injected into the injection well. According to this step, by applying a constant or intermittent pressure to the organic matter adhering to the soil particles, the separation and separation of the organic matter and the mobility of the separated and separated organic matter are maintained and improved. Recovery efficiency is improved.

  A third example of the water permeability maintenance improving step suitable for use in the present invention is a step of stirring and mixing the soil purifier and the soil with a stirring and mixing device. According to this process, the soil contaminated with the organic matter can be reliably purified by the stirring and mixing device, and the organic matter peeled and separated from the soil particles does not cause clogging.

  A fourth example of the water permeability maintenance and improvement process suitable for use in the present invention is to excavate soil in a contaminated area to a position above the groundwater surface, and after covering the excavated surface with a plate-like member or an airtight sheet, It is a step of constructing embankment on the member or sheet. According to this process, since the upper part of the groundwater surface is covered with a plate-like member or an airtight sheet, groundwater and gas are unlikely to leak from the contaminated area, and loss of water head pressure in the injection well can be prevented. The pressure can reach far.

  A fifth example of the water permeability maintenance improving process suitable for use in the present invention is a process of spraying a soil purifier from a position above the groundwater surface. According to this step, the soil purification agent is supplied from the side and the upper direction with respect to the contaminated area, so that the soil purification agent is reliably supplied to the contaminated area and the purification efficiency is good.

  A sixth example of the water permeability maintenance and improvement step suitable for use in the present invention is a step of stirring the soil in the center of the contaminated area before injecting the soil purification agent from the injection well. According to this step, even when the organic substance separated and separated is petroleum having a high viscosity, water permeability is ensured and the organic substance can be easily and reliably recovered.

  A seventh example of the water permeability maintenance improving process suitable for use in the present invention is a process of providing a horizontal hole with a rod-shaped member in soil in a contaminated area. According to this step, since the soil density is reduced and the water permeability is improved, the organic substance separated and separated can be easily collected.

  The eighth example of the water permeability maintenance improving process suitable for use in the present invention is a process of heating the soil in the contaminated area by a heating means such as steam. According to this step, the organic material peeled and separated from the soil particles is heated to lower the viscosity, so that the organic material can be easily recovered without causing clogging.

  A ninth example of the water permeability maintenance improving process suitable for use in the present invention is a process of injecting a soil purification agent having a concentration lower than that of water or previously injected after injecting the soil purification agent. According to this step, the organic matter peeled and separated from the soil particles by the relatively high concentration soil purifier injected earlier is swept away by the water injected later or the relatively low concentration soil purifier. Organic matter can be easily recovered without clogging

  A tenth example of the water permeability maintenance and improvement process suitable for use in the present invention is a process of excavating soil in a contaminated area to remove organic matter that has risen to the vicinity of the excavated surface by capillary action. According to this process, even when the organic matter separated and separated from the soil particles is clogged in the gap between the soil particles, the organic matter can be removed from above the contaminated area, so that the influence of the clogging is minimized. Can be suppressed

  An eleventh example of the water permeability maintenance and improvement process suitable for use in the present invention is that a water shielding layer is provided above and below the contaminated area, and a Fenton agent, a surfactant, etc. are provided in the area sandwiched by the water shielding layer. This is a step of injecting water or a soil purification agent after injecting the chemical. According to this process, since the chemicals injected into the contaminated area are concentratedly supplied to the contaminated area without flowing into the surrounding soil, the purification efficiency of the contaminated soil is improved, and the organic substances separated from the soil particles are separated. The risk of clogging in the gaps between the soil particles is also reduced.

  A twelfth example of the water permeability maintenance improving process suitable for use in the present invention is a process of injecting a soil purification agent at a high pressure from the tip of the injection pipe penetrating into the contaminated area toward the contaminated area. According to this process, since the contaminated area is agitated and mixed with the high-pressure soil cleansing agent, there is sufficient space in the soil, and organic substances that are separated from the soil particles may clog in the soil particle gaps. Less is.

  A thirteenth example of the water permeability maintenance improving process suitable for use in the present invention is a process of recovering organic matter from a vertical drain provided between an injection well and a pumping well. According to this process, the organic matter separated and separated from the soil particles is recovered sequentially from the vertical drain by appropriately adjusting the number of vertical drains, and therefore the risk of the organic matter becoming clogged in the gaps between the soil particles is reduced. The

  A fourteenth example of the water permeability maintenance and improvement process suitable for use in the present invention removes organic matter that has risen to the ground surface of the contaminated area after a large-scale vibration is applied to the contaminated area to cause liquefaction. It is a process. According to this step, separation and separation of the organic matter from the soil particles are promoted, and the organic matter is recovered using a liquefaction phenomenon, so that the organic matter is less likely to be clogged in the soil.

  A fifteenth example of the water permeability maintenance and improvement process suitable for use in the present invention is a process of injecting a soil purification agent at a high pressure obliquely upward toward the contaminated area from the tip of the injection pipe inserted to the lower end of the injection well. . According to this step, since the contact area between the soil purification agent and the contaminated area is increased, the contaminated soil can be purified efficiently, and the risk of clogging the separated and separated organic matter is reduced.

  A sixteenth example of the water flow maintenance and improvement process suitable for use in the present invention is that a sparging well is provided between the injection well and the pumping well so that its tip reaches below the contaminated area, and the tip of the sparging well This is a step of injecting high-pressure air from. According to this step, the separation and separation of the organic matter adhering to the soil particles is promoted by the action of the high-pressure air, and the separated and separated organic matter can be easily moved along with the air. Is less likely to cause clogging.

  A seventeenth example of the water permeability maintenance and improvement process suitable for use in the present invention is that an alkaline solution is used as the soil purification agent or a Fenton agent such as hydrogen peroxide is injected before the soil purification agent is injected. This is a step of reducing the viscosity of the organic matter. According to this process, even when the organic matter is petroleum having high viscosity such as C heavy oil, the viscosity is reduced by the action of the alkaline solution or the concentration is reduced by the action of the Fenton agent. There is little risk of clogging of the separated organic matter in the gaps between the soil particles.

  An eighteenth example of the water permeability maintenance and improvement process suitable for use in the present invention is a process in which a positively charged soil cleaning agent is used as a soil cleaning agent, an anode is disposed in the injection well, and a cathode is disposed in the pumping well to energize. It is. According to this step, the separated and separated organic matter can be easily moved along with the positively charged soil purification agent (cation), and therefore the organic matter is less likely to be clogged in the soil.

  A nineteenth example of the water permeability maintenance improving process suitable for use in the present invention is a process of vacuuming organic matter through a suction pipe reaching the contaminated area from the ground surface. According to this step, even when the organic matter peeled and separated from the soil particles is clogged between the soil particles, the organic matter is directly sucked by the suction pipe, so that the organic matter is not clogged in the soil.

  A twentieth example of the water permeability maintenance and improvement process suitable for use in the present invention is provided with a horizontal well having an opening in the peripheral surface so as to penetrate the contaminated area in the horizontal direction, and the soil purifier is introduced from the inlet of the horizontal well. And pumping water from the pumping well of the pumping well or horizontal well. According to this step, the distance that the separated and separated organic matter moves through the soil is reduced, so that the possibility that the organic matter is clogged in the gap between the soil particles is reduced.

  A twenty-first example of the water permeability maintenance and improvement process suitable for use in the present invention is a process of providing a cylindrical member so as to penetrate the contaminated area in the vertical direction and injecting a soil purification agent at a high pressure from the lower end of the cylindrical member. is there. According to this process, since water pressure is applied to the soil restricted in the surrounding area, the organic matter separated and separated is pushed upward together with the groundwater, and the possibility that the organic matter is clogged in the gap between the soil particles is reduced. The

The above-described first to twenty-first process examples can be combined in two or more as necessary.
In the present invention, an aqueous solution containing a surfactant is preferably used as the soil purification agent, and in particular, a composition containing a polyoxyalkylene alkyl ether and an amine compound, or di-2-ethylhexyl sulfosuccinate sodium as the surfactant. A composition containing (AOT) and an antali earth metal salt is preferably used. By carrying out the method of the present invention using these, even if the object to be purified is petroleum oil with high viscosity such as C heavy oil, these oils adhering to the soil particles are easily separated and separated and contaminated. The soil can be purified.

  According to the soil purification method of the present invention, even when the pollutant is mainly oil with a high viscosity such as C heavy oil, the entire purification operation can be efficiently performed in a shorter time without reducing the purification efficiency in the course of the purification operation. Can be performed automatically.

  The present invention provides a plurality of injection wells and a pumping well arranged between them so as to reach below the groundwater surface of a contaminated area including soil contaminated with organic matter such as heavy oil, and a surfactant is provided from each injection well. This is an in-situ purification method for injecting a soil purification agent having a contained aqueous solution as a typical example, pumping water from a pumping well, and performing an operation for maintaining and maintaining the water permeability of the soil.

Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing a preferred example of a soil purification system used in the soil purification method of the present invention. A soil purification system 100 shown in FIG. 1 includes a contaminated region (organic matter) existing in a saturated layer 2 in a contaminated region where an unsaturated layer (non-aquifer) 1 and a saturated layer (aquifer) 2 are present in order from the ground surface. This is a system for purifying the layer 3 in-situ.

  The organic matter that causes soil contamination is not particularly limited, but the present invention is suitable as a method for purifying soil contaminated with oil such as mineral oil, synthetic oil and animal and vegetable oil, and waste oil thereof. Among the oils, examples of the mineral oil include fuel oils such as gasoline, kerosene, light oil and heavy oil, and lubricating oils.

  In the soil purification system 100, a plurality of injection wells 10 and a pumping well 11 located in the middle of them are provided separately in the contaminated area. The injection well 10 and the pumping well 11 are provided so as to reach below the groundwater surface L, that is, their lower ends are located below the groundwater surface L. In the saturated layer 2, the injection well 10 A dynamic gradient of groundwater from the water to the pumping well 11 is formed. A plurality of, for example, 3 to 15, injection wells 10 are installed so as to surround the organic material layer 3, and the pumping well 11 is installed almost at the center of the installed water injection well 10 (the central part of the contaminated area).

  A drug mixture supply device 31 is connected to the upper end of the injection well 10 via a pipe 32. As a result, the soil purification agent (medicine) is injected into the saturated layer 2 from the drug mixing and supplying device 31 through the injection well 10. Examples of the soil purification agent that can be used in the present invention include organic stripping agents, chemical oxidizing agents, and oil softening agents.

  Examples of the organic release agent include alkali agents such as sodium carbonate and sodium silicate, anionic or nonionic surfactants, and these are injected in the form of an aqueous solution. As the chemical oxidizing agent, there are agents for the Fenton reaction such as citric acid, ferrous sulfate, hydrogen peroxide and the like. As the oil softener, there are hydrocarbon solvents mainly composed of vegetable solvents, light mineral oils, alkanes, and cycloalkanes.

  In the present invention, among these soil purification agents, it is preferable to use an aqueous solution of a surfactant. Specifically, a composition containing a polyoxyalkylene alkyl ether and an amine compound, or a composition containing di-2-ethylhexyl sulfosuccinate sodium (AOT) and an alkaline earth metal salt such as magnesium sulfate or calcium chloride. Use is particularly preferred. The surfactant is used in the form of an aqueous solution.

  The soil purifier injected into the saturated layer 2 from the injection well 10 moves in the saturated layer 2 along the groundwater flow A and reaches the organic layer 3. And the organic substance adhering to the soil particle contained in the organic substance layer 3 is decomposed | disassembled and separated by the soil purification agent, and contaminated soil is purified. At this time, when the organic matter to be purified is petroleum having a high viscosity such as C heavy oil, the separated and separated organic matter is clogged in the gaps between the soil particles, and the water permeability of the soil is reduced. It can be difficult. Therefore, in the present invention, it is possible to prevent the soil permeability from being lowered due to the organic matter by the water permeability maintenance improving step, or to improve the soil permeability lowered due to the organic matter, and to separate the soil. The groundwater containing the separated organic matter can be easily collected.

A pumping pump 20 is connected to the upper end of the pumping well 11 through a pipe 23, and pumped water (mixed liquid of medicine, water, and organic matter) is pumped up by the pumping pump 20. The collected pumped water is sent from the pumping pump 20 to the oil / water separation tank 21 and the fractionator 22, and the pumped water is separated into a mixed solution A of the drug and organic matter and a mixed solution B of the drug and water. The separated mixed solution A is recovered from the pipe 27. On the other hand, the separated mixed solution B is sent to the drug mixture supply device 31 through the pipe 28 and is reused after adjusting the concentration of the drug.
Examples of the water permeability maintenance and improvement means used in the present invention include the following. 2-13 is explanatory drawing of these.

(1) Applying vibration When the soil purifier injected into the saturated layer 2 from the injection well 10 reaches the organic matter layer 3, the organic matter adhering to the soil particles of the organic matter layer 3 is decomposed and separated by the soil purifier. At this time, the organic layer 3 is vibrated by a vibrating body such as the vibrating roller 41, a flat vibrator (not shown), and a rod-like vibrator 42. The application of vibration to the organic layer 3 is preferably performed simultaneously with the injection of the soil purification agent from the injection well 10 so that the separated and separated organic matter is not clogged in the gaps between the soil particles. After completion of the injection, the vibration can be applied to eliminate the clogging of the organic matter, and the injection of the soil purification agent and the application of the vibration can be alternately repeated. This facilitates the separation and separation of the organic matter adhering to the soil particles, and the organic matter separated and separated does not clog in the gap between the soil particles, and the organic matter is saturated along the groundwater flow A. 2 and smoothly recovered (FIG. 2).

(2) Pressurized injection When injecting the soil purification agent from the injection well 10, a constant or intermittent pressure is applied to the soil purification agent by the pressure pump 51 connected to the upper end of the injection well 10. The pressurization to the soil purification agent is preferably performed simultaneously with the injection of the soil purification agent from the injection well 10 so that the separated and separated organic matter is not clogged in the gaps between the soil particles. After completion of the injection of water, pressurization can be performed to eliminate clogging of organic matter, and injection and pressurization of the soil purification agent can be alternately repeated. As a method for pressurizing the soil purification agent, a method in which the upper end of the injection well 10 is covered and then pressurized by the pressurizing pump 51 is preferable. However, the pressure is obtained by the head difference between the injection well 10 and the pumping well 11. It may be. At this time, the pressure applied to the soil purification agent is about 1 kPa to 100 kPa, although it depends on the soil quality. More specifically, the amount of soil purification agent injected from the injection well 10 is increased to increase the water level of the injection well 10, and the amount of pumping from the pumping well 11 is decreased to decrease the level of the pumping well 11. Therefore, there is a method of increasing the dynamic water gradient from the injection well 10 to the pumping well 11. In addition, after a well is provided between the injection well 10 and the pumping well 11, the organic matter separated from the soil particles is first recovered by pumping from the well, and after the soil purification upstream of the well is completed, An operation of injecting a soil purification agent from the well, pumping water from a well provided on the downstream side, and recovering organic matter separated and separated from the soil particles may be sequentially performed. In this case, it is effective to obtain a larger hydrodynamic gradient by narrowing the interval between the wells. As a result, the flow A of groundwater from the injection well 10 to the pumping well 11 is strengthened, so that the organic matter separated and separated from the soil particles is not clogged in the gaps between the soil particles, and the organic matter flows into the groundwater flow A. Along the saturated layer 2 and smoothly recovered (FIG. 3).

(3) Stirring and mixing When the soil purifier injected into the saturated layer 2 from the injection well 10 reaches the organic matter layer 3, the organic matter adhering to the soil particles in the organic matter layer 3 is decomposed and separated by the soil purifier. At this time, a stirrer / mixer 61 such as a trencher is inserted into the organic layer 3 to stir and mix the soil purifier and the soil of the organic layer 3. The stirring and mixing of the soil is preferably performed for the purpose of eliminating the clogging of the organic matter after the injection of the soil purification agent from the injection well 10 is completed. It can be carried out so as not to be clogged with the gaps between the soil particles, and the soil purifying agent can be injected and stirred and mixed alternately. As a result, the organic layer 3 is reliably purified and the organic material peeled and separated from the soil particles is not clogged in the gaps between the soil particles (FIG. 4).

(4) Purification site sealing Excavate the soil in the contaminated area to a position above the groundwater surface, cover the excavated surface with a plate-like member or air-tight sheet 71, and then apply embankment on the member or sheet 71 Backfill. Then, an injection well 10 and a pumping well 11 are provided in the contaminated area, and a soil purification agent is injected from the injection well 10 and pumped up from the pumping well 11 to purify the contaminated soil. As a result, the outflow of groundwater and gas from the contaminated area covered with the plate-like member or the airtight sheet is suppressed and loss of the head pressure in the injection well 10 is prevented, so that the pressure applied from the injection well 10 is far away. In addition, the flow A of groundwater is strengthened and the purification efficiency of the organic layer 3 is improved (FIG. 5).

(5) Surface spraying The injection well 10 and the pumping well 11 are provided in the contaminated area, the soil purification agent is injected from the pouring well 10 and pumped from the pumping well 11, and the spraying device (spraying nozzle) from a position above the groundwater surface. ) 81 to clean up the contaminated soil by spraying a soil cleaner. Thereby, since the soil purifier is supplied from the side and the upper direction with respect to the contaminated area, the purification efficiency of the organic substance layer 3 is improved (FIG. 6).

(6) Unraveling the central part of the contaminated area First, the soil above the central part of the contaminated area (excavated place) is excavated by a drilling device such as a backhoe to expose the upper surface of the contaminated area (organic matter layer 3). Next, after stirring the soil in the central portion (stirring location) of the contaminated area (organic matter layer 3) by the stirring and mixing device 61 such as a trencher, the excavated soil is backfilled. Finally, an injection well 10 is provided outside the contaminated area, a pumping well 11 is provided in the center of the contaminated area, and a soil purification agent is injected from the injection well 10, and groundwater is pumped by the pump 20 in the center of the contaminated area. Suction and pump from pumping well 11. As a result, the water permeability of the groundwater containing the organic matter separated and separated from the soil particles is improved, so that the organic matter is reliably recovered without causing clogging in the gaps between the soil particles (FIG. 7).

(7) Formation of water flow path An injection well 10 and a pumping well 11 are provided in the contaminated area, a soil purification agent is injected from the pouring well 10 and pumped up from the pumping well 11, and the soil in the contaminated area is horizontal by a rod-shaped member. The contaminated soil is purified by making holes 91 in the direction. As a result, a water path is formed in the soil in the contaminated area, and the organic matter peeled and separated from the soil particles is reliably recovered without causing clogging in the gaps between the soil particles (FIG. 8).

(8) Heating of the contaminated region In the organic layer 3 by injecting steam from the steam injection well 46 into the organic material layer 3 using the steam injection device 45 or by injecting a preheated soil purification agent from the injection well 10. The temperature of the groundwater is heated in the range of 30 to 80 ° C. Note that a heated fluid such as warm water can be used instead of steam. In addition, since the reactivity at high temperature may be low depending on the type of the soil purification agent, in such a case, the soil purification agent is injected after appropriately cooling the groundwater heated with steam or the like. As a result, the organic substance peeled and separated from the soil particles is heated and its viscosity is lowered, so that the organic substance is easily recovered without causing clogging in the gaps between the soil particles (FIG. 9).

(9) Method of Injecting Drug First, a relatively high concentration soil purifier supplied from the drug mixture supply device 31 is injected from the injection well 10, and water supplied from the liquid supply device 47 after a predetermined time or relatively low Contaminated soil is purified by injecting a soil cleaner at a concentration. Then, this process is repeated as necessary. As a result, the organic matter exfoliated and separated from the soil particles by the relatively high concentration soil purification agent injected earlier is swept away by the water or the relatively low concentration soil purification agent injected later. It can be easily recovered without causing clogging (FIG. 10).

(10) Stripping of covered soil When the soil purifier injected into the saturated layer 2 from the injection well 10 reaches the organic matter layer 3, the organic matter adhering to the soil particles of the organic matter layer 3 is separated and separated by the soil purifier, At this time, a phenomenon is observed in which the mixed liquid of the soil purifier and the organic matter rises in the soil above the organic matter layer 3 by capillary action. Therefore, the soil above the organic layer 3 is excavated to a certain depth, and the excavated soil is temporarily placed in the vicinity of the contaminated area 3, and the mixed liquid that has risen on the excavated surface is removed by suction with a vacuum pump or the like. Then, the excavated soil that has been temporarily placed is backfilled on the purified soil. At this time, the soil may be excavated to the groundwater surface to remove the mixed solution floating on the groundwater surface. The removed treatment liquid is sent to the oil / water separation tank and subjected to purification treatment. As a result, even when the organic matter peeled and separated from the soil particles is clogged in the gaps between the soil particles, the organic matter can be removed from above the organic matter layer 3, thereby minimizing the influence of clogging. (FIG. 11).

(11) Upper and lower water-impervious layers Water-impervious materials such as cement mortar and bentonite are press-fitted above and below the organic material layer 3 to provide a water-impervious layer 48, and an injection pipe 49 is inserted in the region sandwiched between the upper and lower layers Inject a drug such as a Fenton agent or surfactant, and leave it for a while. Thereafter, water or a soil purification agent is injected from the injection well 10 and pumped up from the pumping well 11, thereby recovering the organic matter peeled and separated by the chemical. Thereby, since the chemical | medical agent inject | poured into the organic substance layer 3 is intensively supplied to the organic substance layer 3 without flowing out into the surrounding soil, the purification efficiency of contaminated soil is improved and the organic substance exfoliated and separated from the soil particles is soiled. The risk of clogging in the interstices between particles is also reduced (FIG. 12).

(12) Free-propulsion high-pressure water injection When the injection pipe 55 penetrates into the soil from the pumping well 11 in the vicinity of the injection well 10 and the tip of the injection pipe 55 reaches the organic substance layer 3, the tip is moved to the pumping well 11 The soil purifier is sprayed at a high pressure (water jet) from a high pressure spray nozzle that is bent toward the horizontal direction toward the top and provided at the tip. Then, when the soil purification agent and the organic matter adhering to the soil particles of the organic matter layer 3 are stirred and mixed to become a slurry-like mixed liquid, water is poured from the injection well 10 and pumped from the pumping well 11. Collect the mixed solution to purify contaminated soil. Further, when the tip of the injection pipe 55 is bent in the horizontal direction and reaches the uncontaminated contaminated area of the organic material layer 3, the soil purifier is sprayed from the high pressure spray nozzle at a high pressure. The contaminated soil is purified in the same way. Thereafter, the same operation is repeated to purify the entire organic material layer 3. As a result, the contaminated area is agitated and mixed with a high-pressure soil cleansing agent, so that there are sufficient voids in the soil, and there is little risk of clogging of organic matter separated and separated from the soil particles in the gaps between the soil particles ( FIG. 13).

(13) Vertical drain After providing vertical drains 56, such as a paper drain, a gravel drain, and a sand drain, between the injection well 10 and the pumping well 11, the soil purifier is injected from the injection well 10. The injected soil purifying agent penetrates into the organic substance layer 3, and the organic substances adhering to the soil particles are separated and separated by the action, and flows out to the vertical drain 56 together with the groundwater. The mixed liquid of the organic matter and the ground water is pumped up from the vertical drain 56 and collected, and then subjected to purification treatment. As a result, by appropriately adjusting the number of the vertical drains 56, the organic matter separated and separated from the soil particles is sequentially collected from the vertical drains 56, so that the risk of the organic matter becoming clogged in the gaps between the soil particles is reduced. (FIG. 14).

(14) Forced liquefaction By injecting the soil purification agent from the injection well 10 and pumping it from the pumping well 11, the organic matter layer 3 is allowed to stand for a while in the state in which the soil purification agent is infiltrated. After a predetermined time has elapsed, a large-scale vibration is applied to the soil including the organic material layer 3 by the vibration generator 57. This vibration causes the soil containing the organic matter layer 3 to liquefy, and the organic matter separated and separated from the soil particles by the action of the soil purifier rises to the ground surface together with the groundwater. Clean up the contaminated soil by removing with suction. As a result, the separation and separation of the organic matter from the soil particles are promoted, and the organic matter is recovered by utilizing the liquefaction phenomenon, so that the organic matter is less likely to be clogged in the soil (FIG. 15).

(15) High-pressure water oblique upward injection When the injection pipe 58 is inserted into the injection well 10 and its tip reaches the lower end of the injection well 10, the soil purifier is applied from the high-pressure injection nozzle provided at the tip of the injection pipe 58. Injected with high pressure (water jet). At this time, the spraying direction of the soil purifier sprayed from the high pressure spray nozzle is set obliquely upward as shown in FIG. An opening is provided at the lower end of the injection well 10 so that the soil purifier can be sprayed. The soil purifier sprayed into the soil penetrates the soil, reaches the lower surface of the organic material layer 3 and separates and separates the organic material adhering to the soil particles. Thereby, since the contact area of a soil purification agent and the organic substance layer 3 becomes large, the contaminated soil can be purified efficiently, and the possibility that the separated and separated organic substances are clogged is reduced. In place of the method using the water jet described above, a ground water flow B as shown in FIG. 16 is generated by causing the soil purifier to flow from the lower end of the injection well 10 to the saturated layer 2 and pumping it from the pumping well 11. Then, the soil purification agent may be put on the groundwater flow B to reach the lower surface of the organic material layer 3. (FIG. 16).

(16) Air sparging A sparging well 59 is provided in the middle of the injection well 10 and the pumping well 11 so that the tip thereof is sufficiently below the organic material layer 3, and high pressure air is supplied from the tip of the sparging well 59. Spray. The air rises in the soil and reaches the organic substance layer 3, and the organic substances attached to the soil particles are separated and separated by the action of the air. And the organic substance which peeled and isolate | separated is collect | recovered by pouring water from the injection well 10 and pumping it from the pumping well 11. This facilitates the separation and separation of the organic matter adhering to the soil particles by the action of high-pressure air, and the organic matter separated and separated can easily move along with the air, so that the organic matter is clogged in the soil. Is less likely to occur (FIG. 17).

(17) Soil alkalinization / pre-fenton treatment An alkaline soil cleaner having a pH of about 9 to 10 is injected from the chemical mixture supply device 31 into the injection well 10 and left for a while in a state where an alkaline solution is infiltrated into the organic layer 3. . And if the viscosity of the organic substance exfoliated and separated from the soil particles is sufficiently lowered by the alkaline solution, the organic substance separated and separated is recovered by pumping water from the pumping well 11, and the contaminated soil is purified. In this case, a neutralizing agent is added to the alkalinized soil after the purification treatment to complete the neutralization treatment. In addition, a Fenton agent such as hydrogen peroxide solution may be used in place of the alkaline solution. In this case, after the organic matter is decomposed by the action of the Fenton agent and its concentration is reduced, the soil purification agent is injected to contaminate. Purify the soil. As a result, even when the organic matter is petroleum such as C heavy oil, the viscosity is reduced by the action of the alkaline solution or the concentration is reduced by the action of the Fenton agent. There is little risk of organic matter clogging in the gaps between soil particles (FIG. 18).

(18) Electrophoresis Method A positively charged soil purification agent such as a cationic surfactant is injected from the injection well 10 so that the organic layer 3 is infiltrated with cations. Then, a positive electrode (anode) 75 is arranged in the injection well 10 and a negative electrode (cathode) 76 is arranged in the pumping well 11 and energized, so that it is separated from the soil particles by the action of the soil purifier. A positively charged soil purifier (cation) holding organic matter is moved from the injection well 10 to the pumping well 11, and the organic matter separated and separated is recovered by pumping water from the pumping well 11. As a result, the separated and separated organic matter can be easily moved along with the positively charged soil purification agent (cation), so that the organic matter is less likely to be clogged in the soil (FIG. 19).

(19) Vacuum suction A soil purification agent is injected from the injection well 10 and pumped up from the pumping well 11 to generate a groundwater flow A and permeate the soil purification agent 3 into the organic material layer 3. Then, the suction pipe 77 reaching the organic substance layer 3 from the ground surface is penetrated and vacuum suction is performed by the vacuum pump 78, whereby the organic matter separated from the soil particles by the action of the soil purification agent is recovered. As a result, even when the organic matter peeled and separated from the soil particles is clogged between the soil particles, the organic matter is directly sucked by the suction pipe 77, so that the organic matter is not clogged in the soil (FIG. 20). ).

A mode (second mode) in which the stirring and mixing (3) and the unraveling (6) at the center of the contaminated area are performed without using an injection well or the like will be described below.
FIG. 11 shows a second aspect. In this figure, 61 is an excavating machine (backhoe) and 62 is a mixing machine (stabilizer). First, the soil above the contaminated area 3 is excavated by the backhoe 61 to expose the contaminated area 3. At this time, the excavated soil is temporarily placed in the vicinity of the contaminated area 3. Next, the drug and the contaminated soil are stirred and mixed by the mixing device provided in the stabilizer 62 while the drug is uniformly distributed on the exposed surface of the contaminated region 3 by the drug spraying device provided in the stabilizer 62. When the stirring and mixing is completed, the treatment liquid mixed with the chemical and the organic substance is removed by suction with a vacuum pump or the like, and then the temporarily placed excavated soil is backfilled above the purified soil. The removed treatment liquid is sent to an oil-water separation tank and separated into a mixed liquid A of chemical and organic substance and a mixed liquid B of chemical and water. The mixed liquid A is discarded, and the mixed liquid B is added with the chemical and then It is sent to a chemical spraying device and reused as a soil purification agent (medicine). In addition, a trencher type mixing machine etc. can also be used as a mixing machine used for this construction method.

  FIG. 12 shows another example of the second mode. In this figure, 63 is a ground improvement machine (mud stabilizer), 65 is a purification fluid production plant, 66 is a chemical supply device, 67 is an air compressor, 68 is a generator, and 69 is a processing pile.

  The center of the rotating rod 64 attached to the electric motor of the ground improvement machine 63 is set at the excavation position on the ground above the contaminated area 3, and the rotating rod 64 is lowered while being rotated by the electric motor, and the tip of the rotating rod 64 is moved. The soil in the unsaturated layer is excavated by spraying high pressure water from. The diameter of the excavation hole at this time is usually about 30 cm. On the other hand, in the purification fluid manufacturing plant 65 provided in the vicinity of the ground improvement machine 63 on the ground, the purification fluid (medicine) is manufactured using the soil purification agent supplied from the chemical supply device 66. When the tip of the rotating rod 64 reaches the upper end of the contaminated area 3 (saturated layer), the medicine is pumped by a pump and sent through the inside of the rotating rod 64 to a nozzle hole provided slightly above the tip of the rotating rod 64. Then, while discharging the medicine and air in a horizontal direction at a high pressure, the rotating rod 64 is further spirally rotated to penetrate and mix the soil and the medicine in the contaminated area 3 with stirring. The stirring and mixing range at this time is about 1 m in radius with the rotating rod 64 as the center, and in this range, the drug, organic matter, and water (ground water) are mixed to form a slurry. In addition, the stirring and mixing is performed so that adjacent stirring and mixing ranges are overlapped with each other so that no purification leakage occurs. When the tip of the rotating rod 64 reaches the lower end of the contaminated area 3, the discharge of the medicine is stopped and the rotating rod 64 is pulled out. When the stirring and mixing is completed, the mixed solution of the chemical, the organic matter and the water (ground water) is collected by the well point well that has been previously driven. Then, the contaminated area is purified by repeating the above operation.

  In this example, the medicine is discharged at the time of penetration, but it may be stirred and mixed both at the time of penetration and at the time of withdrawal. In addition, here, an example is shown in which a medicine is jetted from the tip of the rotating rod 64 by a water jet, and the contaminated soil and the medicine are stirred and mixed by the jet pressure. However, the contaminated soil is replaced by a stirring blade instead of the water jet. A method of stirring and mixing the drug and the drug can also be used.

  FIG. 13 is an explanatory view showing a third embodiment of the soil purification method of the present invention. First, a soil purifier is sprayed from the ground surface above the contaminated area 3 using a spraying device (spraying nozzle) 81. Next, the pumping well 11 is provided in the central part of the contaminated area 3, and pumping is performed from the pumping well to collect a mixed liquid of the medicine and the organic matter.

  FIG. 24 is explanatory drawing which shows 4th Embodiment of the soil purification method of this invention. In this figure, 85 is a horizontal well. A horizontal well 85 is provided so as to penetrate the organic material layer 3 in the horizontal direction, and a soil purification agent is injected from an inlet 86 of the horizontal well 85. A portion of the horizontal well 85 that is present in the organic layer 3 is provided with a large number of openings on the entire peripheral surface, and the soil purifier injected into the horizontal well 85 flows into the soil through the openings. The organic substance adhering to the particles is separated and separated. The separated and separated organic matter is taken into the horizontal well 85 from the opening and collected by pumping from the pumping port 87 of the pumping well 11 or the horizontal well 12. As a result, the distance that the separated and separated organic matter moves through the soil is reduced, so that the possibility of the organic matter becoming clogged in the gap between the soil particles is reduced.

  FIG. 25 is an explanatory view showing a fifth embodiment of the soil purification method of the present invention. In this figure, 88 is a cylindrical member and 89 is an injection tube. A cylindrical member 88 is provided so as to penetrate the organic material layer 3 in the vertical direction, and pressure water containing a soil purification agent is injected from the lower end portion of the cylindrical member 88 through the injection pipe 89. Then, when the pressure water rises in the soil inside the cylindrical member 88 and passes through the organic substance layer 3, the organic substance attached to the soil particles is separated and separated, and the organic substance is entrained to further remove the cylindrical substance 88. Ascend in the soil inside. Finally, the organic matter floating on the surface of the soil located at the upper end of the cylindrical member 88 is collected by a vacuum pump or the like to purify the contaminated soil. As a result, water pressure is applied to the soil restricted in the surroundings, so that the organic matter separated and separated is pushed upward together with the groundwater, and the possibility that the organic matter is clogged in the gap between the soil particles is reduced.

〔Example〕
In order to confirm the effect of the present invention, the following tests were conducted.
A laboratory test water tank (width 20 cm × height 18 cm × length 70 cm) shown in FIG. 14 is filled with No. 4 silica sand containing 5% C heavy oil to a height of 18 cm, and the agent a (interface) is used as a soil purification agent from the upper surface. Activating agent aqueous solution: polyoxyalkylene alkyl ether and amine compound, surfactant concentration 1%), drug b (surfactant aqueous solution: AOT and ant earth metal salt, surfactant concentration 1%) at a flow rate of 20 ml / min. I passed water. At this time, the height of the water flow surface was about 14 cm, the dynamic water gradient was 0.5 cm, and the water flow time was 49 hours. Moreover, operation shown in Table 1 was performed together with the water flow of each chemical | medical agent. Table 2 shows the results of confirming water permeability and heavy oil removability for each example and comparative example.

  From this test result, according to Examples 1 to 7 related to the soil purification method of the present invention, even when the purification target is C heavy oil having a high viscosity, the water permeability of the soil can be kept good, and the C heavy oil can be recovered. It was confirmed that this could be done sufficiently. On the other hand, in the comparative example in which no operation was performed, the C heavy oil peeled and separated by the soil purifier clogged in the gaps between the soil particles, and the water hardly passed and the C heavy oil could not be recovered. It was.

  According to the method of the present invention, the organic substances separated and separated by the soil purification agent are not clogged in the soil by performing the operations A to I together with the purification of the contaminated soil by the soil purification agent. Since it is easily recovered, the performance of the soil purification agent can be sufficiently exhibited as compared with the prior art, and the purification efficiency is improved.

  The soil purification method of the present invention is useful as an in-situ purification method for a contaminated area including soil contaminated with oil such as a refinery site.

Explanatory drawing which shows an example of the soil purification system used with the method of this invention. Explanatory drawing of a vibration provision system. Explanatory drawing of a pressure injection system. Explanatory drawing of a stirring mixing system. Explanatory drawing of a purification location sealing system. Explanatory drawing of a surface spraying system. Explanatory drawing of the loosening method of the contamination area center part. Explanatory drawing of a water flow path formation system. Explanatory drawing of a contamination area | region heating system. Explanatory drawing of a chemical injection system. Explanatory drawing of a covering soil peeling method. Explanatory drawing of an up-and-down impermeable layer system. Explanatory drawing of a free propulsion high pressure water injection system. Explanatory drawing of a vertical drain system. Explanatory drawing of a forced liquefaction system. Explanatory drawing of a high-pressure water diagonal upward injection system. Explanatory drawing of an air sparging system. Explanatory drawing of soil alkalinization / prior Fenton processing system. Explanatory drawing of an electrophoresis method system. Explanatory drawing of a vacuum suction system. Explanatory drawing which shows the 2nd aspect of this invention. Explanatory drawing which shows another example of the 2nd aspect of this invention. Explanatory drawing which shows the 3rd aspect of this invention. Explanatory drawing which shows the 4th aspect of this invention. Explanatory drawing which shows the 5th aspect of this invention. The top view and side view which show the water tank for an indoor test in the Example of this invention.

Explanation of symbols

100 Soil purification system 1 Unsaturated layer (non-aquifer)
2 Saturation layer (aquifer)
3 Pollution area (organic matter layer)
DESCRIPTION OF SYMBOLS 10 Injection well 11 Pumping well 20 Pumping pump 21 Oil-water separation tank 22 Fractionation device 23, 24, 25, 26, 27, 28, 32 Piping 30 Injection pump 31 Drug mixing supply device 41 Vibrating roller 42 Bar-shaped vibrator 45 Steam injection device 46 Steam injection well 47 Liquid supply device 48 Impermeable layer 49, 55, 58, 89 Injection pipe 51 Pressure pump 56 Vertical drain 57 Vibrator 59 Sparging well 61 Stirring mixing device 71 Plate member or airtight sheet 75 Positive electrode (anode)
76 Negative electrode (cathode)
77 Suction tube 78 Vacuum pump 81 Spraying device (spraying nozzle)
85 Horizontal well 86 Inlet 87 Pumping port 88 Cylindrical member 91 Hole G Soil L Groundwater level

Claims (27)

  A step of providing a plurality of injection wells and a pumping well disposed between them in a contaminated area including soil contaminated with organic matter so as to reach below the groundwater surface, injecting a soil purification agent from the injection well, and A soil purification method comprising a step of pumping water from a pumping well and a step of maintaining and improving soil water permeability.   The soil purification method according to claim 1, wherein the organic substance is made of oil.   The soil purification method according to claim 1 or 2, wherein the soil purification agent is an aqueous solution containing a surfactant.   The soil purification method according to any one of claims 1 to 3, wherein the water permeability maintenance improving step is a step of applying vibration to the contaminated area by a vibrating body.   The said water permeability maintenance improving process is a process of providing a constant or intermittent pressure with respect to the said soil cleaning agent, when inject | pouring the said soil cleaning agent into the said injection well. The soil remediation method as described in.   The soil purification method according to any one of claims 1 to 5, wherein the water permeability maintenance improving step is a step of stirring and mixing the soil purification agent and the soil by a stirring and mixing device.   In the step of maintaining and improving water permeability, the soil in the contaminated area is excavated to a position above the groundwater surface, and a plate member or an airtight sheet is coated on the excavated surface, and then embankment is formed on the member or sheet. It is a process to construct, The soil purification method of any one of Claims 1-5.   The soil purification method according to any one of claims 1 to 6, wherein the water permeability maintenance improvement step is a step of spraying the soil purification agent from a position above the groundwater surface.   The soil according to any one of claims 1 to 8, wherein the water permeability maintenance improving step is a step of stirring the soil in the center of the contaminated area before injecting the soil purification agent from the injection well. Purification method.   The soil purification method according to any one of claims 1 to 9, wherein the water permeability maintenance improving step is a step of providing a horizontal hole with a rod-shaped member in the soil of the contaminated area.   The soil purification method according to any one of claims 1 to 10, wherein the water permeability maintenance improving step is a step of heating the soil in the contaminated area by a heating means such as steam.   The said water permeability maintenance improvement process is a process of inject | pouring the said soil purification agent of a low density | concentration from what was inject | poured after water or the previously injected | pouring of the soil purification agent. Soil purification method.   The soil according to any one of claims 1 to 12, wherein the water permeability maintenance improving step is a step of excavating the soil in the contaminated area to remove the organic matter that has risen to the vicinity of the excavated surface by capillary action. Purification method.   In the water permeability maintenance improving step, a water shielding layer is provided above and below the contaminated area, and a drug such as a Fenton agent or a surfactant is injected into an area sandwiched between the water shielding layer and then water or The soil purification method according to any one of claims 1 to 13, which is a step of injecting a soil purification agent.   The water permeability maintenance improving step is a step of injecting a soil purification agent at a high pressure from a tip portion of an injection pipe penetrating into the contaminated region toward the contaminated region. Soil purification method.   The soil purification method according to any one of claims 1 to 15, wherein the water permeability maintenance improving step is a step of collecting the organic matter from a vertical drain provided between the injection well and the pumping well.   17. The water permeability maintenance improving step is a step of removing the organic matter that has risen up to the ground surface of the contaminated area after applying large-scale vibration to the contaminated area to generate liquefaction. The soil purification method according to any one of the above.   The water permeability maintenance improving step is a step of injecting a soil purification agent at a high pressure obliquely upward toward the contaminated region from a tip portion of an injection pipe inserted to a lower end portion of the injection well. The soil purification method according to item 1.   In the water flow maintenance and improvement step, a sparging well is provided between the injection well and the pumped well so that the tip thereof reaches below the contaminated area, and high pressure air is injected from the tip of the sparging well. It is a process, The soil purification method of any one of Claims 1-18.   The step of reducing the viscosity of the organic matter by using an alkaline solution as the soil purification agent or injecting a Fenton agent such as hydrogen peroxide before injecting the soil purification agent in the water permeability maintenance improving step. The soil purification method according to any one of claims 1 to 19.   21. The step of maintaining and improving water permeability is a step of applying electricity by using a positively charged soil cleaner as the soil cleaner, arranging an anode in the injection well and a cathode in the pumping well. The soil purification method according to any one of the above.   The soil purification method according to any one of claims 1 to 21, wherein the water permeability maintenance improving step is a step of vacuum suction of the organic matter through a suction pipe reaching the contaminated area from the ground surface.   The water permeability maintenance improving step provides a horizontal well having an opening on a peripheral surface so as to penetrate the contaminated area in the horizontal direction, and injects the soil purification agent from an inlet of the horizontal well, The soil purification method according to any one of claims 1 to 22, which is a step of pumping water from a pumping port of the horizontal well.   The water permeability maintenance improving step is a step of providing a cylindrical member so as to penetrate the contaminated region in the vertical direction and injecting the soil purification agent at a high pressure from a lower end portion of the cylindrical member. The soil purification method according to claim 1.   25. The composition according to claim 3 to 24, wherein the surfactant comprises a composition comprising a polyoxyalkylene alkyl ether and an amine compound, or a composition comprising di-2-ethylhexyl sulfosuccinate sodium (AOT) and an alkaline earth metal salt. The soil purification method according to any one of the above.   The method according to claim 6 or 24, which is carried out without a well.   24. A method according to claim 8 or 23 carried out without an injection well.