JP2004025158A - Cleaning method of polluted stratum and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of cleaning a stratum (a stratum including a soil layer and/or a rock body and ground water) polluted with a harmful chemical substance at the original position, especially a polluted layer cleaning method effective for (bio-augumentation) for introducing bacteria having a high pollutant decomposition capacity, and an apparatus therefor. <P>SOLUTION: Injection wells (3) for injecting a fluid (2) having a cleaning function by either one of physical action, chemical reaction, the metabolism of microorganisms and acceleration thereof and high pressure washing, and recovery wells (4) for recovering the fluid (2) are formed in the polluted stratum (1) at a predetermined interval by drilling. The fluid (2) is introduced into the injection wells (3) under an ultra-high pressure. The fluid (2) is penetrated in the stratum (1) to stir and wash the stratum (1) to separate the pollutant (6). The pollutant (6) is removed by recovering the fluid containing the pollutant (6) or the like. In the stratum (1), the cleaning function due to physical action and chemical reaction or the metabolism of microorganisms is supported by the ultra-high pressure injection of the fluid. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for purifying in situ a stratum (a stratum and / or a rock body including a soil layer and groundwater) contaminated with harmful chemical substances.
[0002]
[Prior art]
In addition to conventionally known heavy metals, contamination of the formation with volatile organic chlorine-based chemical substances (hereinafter also referred to as “VOCs”), for example, organic solvents such as trichloroethylene and tetrachloroethylene has become a serious social problem in recent years. In order to effectively and efficiently remove and detoxify these heavy metals and VOCs (hereinafter also referred to as “contaminants”), the biodegradation reaction of microorganisms as well as chemical methods is used to contaminate the contaminated stratum. Contaminated formation purification methods that are to be purified at locations are being put to practical use.
[0003]
Attention has also been paid to a method of treating an organic chlorine compound more simply in a shorter time by combining a physicochemical reaction with a biological reaction. These in-situ contaminated formation remediation methods are not expected to require large-scale excavation, migration, and backfilling of pollutant-containing soil, and are thus expected to be a technology that enables low-cost purification treatment.
[0004]
In other words, as a purification treatment using physical / chemical methods or microbiological methods (bioremediation), focusing on groundwater veins and installing a water intake facility downstream in the flow direction of pollutants to collect contaminated water and prevent its diffusion For treating contaminated water that has been collected, also for providing a contaminated water treatment area on the downstream side in the flow direction, for treating contaminants that permeate (pass), and inject microorganisms and nutrients upstream of the VOCs contamination source and diffuse it to the contamination area Methods for treating pollutants are known.
[0005]
In addition, when purifying the contaminated soil and / or contaminated groundwater in situ, the biomass is grown under anaerobic conditions using a carbon source and an inorganic reducing agent necessary for the growth and survival of microorganisms (mainly anaerobic bacteria) in the soil. The purpose of this method is to maintain the environment for chemical and physicochemical purification treatment for a certain period of time at low cost completely and without using large-scale dedicated equipment. For example, see Patent Document 1).
[0006]
However, in the case of the above-mentioned method of purifying a contaminated geological formation that depends on the groundwater flow, it is rather reluctant and a method of entrusting the results to the flow of the groundwater. That is, it takes only a long time to treat the pollutants eluted in the groundwater, and elute and purify the pollutants from the entire contaminated stratum which is difficult to purify. Also, the flow of polluted groundwater is not uniform, making it difficult to collect and treat all pollutants. It is also very unlikely that the injected chemicals or microorganisms or nutrients will spread throughout the contaminated formation.
And because of the particularly complex stratum structure, there are many cases in which the pollution is increased with the chemical substances used for purification.
[0007]
Among the bioremediation methods, the technique of introducing bacteria having a high contaminant decomposability (bioaugmentation) may cause the injected microorganisms to diffuse into the surrounding stratum and cause adverse effects. In other words, there was concern about secondary contamination as a side effect, and it was difficult to obtain public acceptance.
[0008]
In the conventional vacuum extraction method, the groundwater level rises to reduce the pressure in the contaminated formation, and when the contaminant is the VOCs or the like, the zone where the contaminant can be vacuum extracted from the contaminated formation is narrow. And purification efficiency is poor. That is, it is difficult to volatilize the VOCs in the saturated water below the groundwater level in the saturated zone below the groundwater surface, and only the contaminated layer above the groundwater surface is purified because the VOCs are hard to volatilize. However, there is a waste that the deepest part of the vacuum extraction well cannot be used effectively.
[0009]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-262751 (Abstract, FIG. 1)
[0010]
[Problems to be solved by the invention]
At present, the tasks required to treat geological formations contaminated by harmful chemicals are as follows.
[0011]
As a first problem, a purification method capable of completely purifying a contaminated stratum in situ and reducing the diffusion of secondary environmental pollution. That is, when using a method of injecting a fluid having a purification function by any of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing from a well, the purification effect spreads to a deeply contaminated stratum, and There is a need for a technique that can prevent the side effects of chemicals and / or microorganisms.
[0012]
As a second problem, even when a method of injecting the fluid from one well and recovering the fluid from the other well is used, even in a wide range of contaminated layers including heavy metal contamination, purification treatment is performed at a high level without unevenness. You need to be able to do it.
[0013]
As a third problem, there is a need for a method of exhibiting a high fixed purification function for all pollutants including heavy metals.
[0014]
As a fourth problem, it is necessary to establish the optimal conditions for improving the destruction effect of the contaminated stratum by minimizing the cost of enhancing special facilities and the like in a plant constructed with consideration for economic effects. .
[0015]
A fifth problem is a method for efficiently collecting volatile pollutants. That is, in order to achieve a certain level of purification or more, it is necessary to remove volatile contaminants remaining in the stratum by forcibly purifying them.
In particular, regarding the purification of VOCs, when contaminants are volatilized from the contaminated stratum and air containing the contaminants is extracted by a vacuum pump, the groundwater level in the saturated zone rises due to the decompression of the contaminated stratum by the vacuum pump. I do. Then, it is difficult to volatilize the VOCs in the contaminated stratum below the groundwater table in the saturated zone, so that the VOCs are not easily volatilized, and only the contaminated stratum shallower than the groundwater table is purified, and the purification is performed. There is a waste that the efficiency of the process is remarkably reduced.
Therefore, with regard to VOCs purification, it is necessary to lower the groundwater table, which is a ninth problem described below.
[0016]
As a sixth problem, if water is used as a purification medium even if water is used without limitation, not only waste of water supply and drainage occurs but also secondary environmental pollution may be diffused. In addition, additives to the purification medium are also wasted. Therefore, by reducing the total amount of the fluid that is the purification medium, it is possible to reduce the amount of additives and thereby save costs, and to establish a method capable of preventing unnecessary diffusion of the fluid and preventing secondary environmental pollution. There is a need.
[0017]
As a seventh problem, in order to reduce the cost of excavating wells, it is necessary to arrange the minimum number of wells so that they can be purified more efficiently.
[0018]
Eighth, ninth, and tenth issues require that existing purification equipment and technologies be used together to increase efficiency. That is, the eighth problem is to utilize the existing fluid cleaning method, the ninth problem is to utilize the high-pressure jet cleaning method, and the tenth problem is to increase the efficiency by using the existing fluid cleaning device together. .
[0019]
In particular, as a ninth problem, VOCs in the contaminated formation below the groundwater table do not volatilize.
Therefore, only the contaminated stratum higher than the groundwater table is purified, and there is a waste that the deepest part of the recovery well cannot be used effectively.
[0020]
As an eleventh problem, similarly to the sixth problem, it is necessary to establish a plant configuration that can prevent secondary environmental pollution by preventing unnecessary diffusion of the fluid.
[0021]
A twelfth task is to inject microorganisms of a single or limited type into the ground at an unusually high density that is not possible in a normal ecosystem, in order to purify the contaminated strata. Conducting bioaugmentation may have adverse effects on ecosystems, and require security measures to gain public acceptance.
[0022]
As a thirteenth problem, a bioaugmentation that obtains public acceptance within a range or an extension of technology and equipment related to an in-situ contaminated formation purification method and apparatus using ultra-high pressure injection is performed, Achieve the goal.
[Means for Solving the Problems]
[0023]
The present invention provides a method of purifying a contaminated geological formation that can be completely carried out in situ, and that has a small diffusion of secondary environmental pollution. That is, even when a method of injecting a fluid having a purifying function by one of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing from one well and recovering the fluid from the other well is used. And / or a method and an apparatus for purifying a contaminated formation that can prevent side effects caused by microorganisms.
[0024]
In the invention according to claim 1, in the contaminated stratum, a pressurized well for pressurizing a fluid having a purifying function by physical action and chemical reaction, and metabolism of microorganisms and promotion or high-pressure washing thereof is formed, Injecting the fluid at a pressure that controls one of the functions of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing from an injection port provided on the wall surface or the bottom of the injection well, and the injected fluid is The contaminants are removed by stirring and washing the formation, separating or decomposing the contaminants, and collecting a fluid containing the undecomposed contaminants in the formation from the recovery well.
[0025]
Because of this, contaminants that remain entangled with the fine particles of the clay or silt or mudstone, which are the constituent particles of the stratum, are controlled to a suitable state for any of the functions of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing. While harmless.
[0026]
In the invention according to claim 2, a recovery well for recovering the fluid having the purifying function and the press-fit wells capable of vertically moving the injection port are formed by drilling at appropriate intervals, and the press-fit well is formed. The role of press-fitting and collecting is exchanged with the collecting well by appropriate rotation, and the wells determined to have contaminants due to heavy metals and / or wells in the vicinity thereof are filled with an ion-exchange substance and an adsorbing substance. . Specific examples of ion exchange substances and adsorption substances include zeolite, allophane, imogolite and activated carbon. Since these ion-exchange substances and adsorbents have a function of adsorbing harmful substances such as heavy metals, contaminants such as heavy metals are taken into the ion-exchange substances and adsorbents and have the effect of sealing off heavy metal poisons.
[0027]
With this configuration, even when a method of injecting the fluid from one well and recovering the fluid from the other well is used, it is possible to purify the contaminated formation in a wide range at a high level without unevenness. In addition, heavy metals can be fixed and purified in the contaminated formation.
[0028]
In the invention according to claim 3, by mixing at least one of the ion-exchange substance and the adsorption substance and the heavy metal mineral forming solution into the fluid, the contaminant due to the heavy metal can be fixed and purified in the contaminated formation.
[0029]
In the invention according to claim 4, a liquid pressurized to a range of 20 to 500 MPa and / or a gas pressurized to a range of 0.1 to 1.0 MPa is injected into the injection well as the fluid.
[0030]
As a result, the clay, silt, or mudstone layer is broken into flakes by a liquid pressurized in the range of 20 to 500 MPa even in a clay or silt or mudstone contaminated layer where the fluid hardly penetrates. Since uniform fine particles are formed, fluid can be permeated, stirred, and washed.
[0031]
In the case of a VOCs-contaminated stratum, if the gas is pressurized in the range of 0.1 to 1.0 MPa, the gas mixes with the groundwater in the stratum to form bubbles, which are accompanied by sparsing, and are impregnated and stirred. The cleaning effect is enhanced, and the air bubbles lift untreated contaminants together with the liquid toward the ground, thereby facilitating detoxification.
A gas is mixed to promote any of the physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing.
[0032]
In the invention according to claim 5, the fluid is sucked from the recovery well by a negative pressure pump. In this case, the pressure in the contaminated stratum around the recovery well is reduced to reduce the volatility of VOCs and the like. Since the contaminant is volatilized from the contaminated stratum, it is easy to perform the detoxification treatment.
[0033]
In the invention according to claim 6 and claim 11, the fluid recovered from the recovery well is detoxified, and a part or all of the detoxified fluid is circulated and used. The total amount of used can be saved. Then, the amount of use of the chemical substance or the microorganism for maintaining any of the functions of the physical action, the chemical reaction, the metabolism of the microorganism and the high-pressure washing is reduced, so that the cost can be reduced. Further, if the fluid is circulated in a closed loop, it is difficult to diffuse secondary environmental pollution.
[0034]
In the invention according to claim 7, the distance from the absorption port provided on the wall surface or the bottom of the recovery well to the injection port via the contaminated formation is set in a range of 0.5 to 5.0 m. This setting discloses the embodiment since the inventor has obtained the most effective result as a result of earnest research.
[0035]
In the invention according to claim 8 and claim 10, in order to detoxify the fluid recovered from the recovery well, contaminant adsorption means and / or aeration means using activated carbon are used in combination, so that existing management resources can be efficiently used. Efficiency can be increased by applying existing technologies that work well. Accordingly, the burden on those who pursue environmental purification is reduced.
[0036]
In the invention according to claim 12, a first step of injecting the fluid from the injection well under conditions that maintain metabolic activity of microorganisms, a second step of purifying a contaminated formation by metabolism of the microorganisms, After the purification of the contaminated formation is completed in step 2, a third step of switching the conditions to kill the microorganism and injecting the fluid from the injection well is provided.
[0037]
In doing so, injecting microorganisms of a single or limited type into the ground at an unusually high density that would not be possible in a normal ecosystem, in order to purify the contaminated strata Conducting bioaugmentation does not cause any adverse effects on the ecosystem, so it can gain public acceptance.
[0038]
In the invention according to claim 13, since the conditions for killing the microorganisms are realized by ultra-high pressure injection exceeding the survival conditions of the microorganisms, the in-situ contaminated formation purification method using ultra-high pressure injection and its method Objectives can be achieved within or on the extension of the technology or equipment associated with the device.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0040]
FIG. 1 is a schematic cross-sectional view of a contaminated stratum illustrating a basic embodiment of the present invention. At a predetermined interval (see FIG. 3), in the contaminated formation 1, a press-in well 3 for injecting a fluid 2 having a purifying function by a physical action, a chemical reaction and metabolism of microorganisms described below and a recovery well 4 for recovering the fluid 2 are provided. And formed by drilling. The fluid 2 is mainly two phases of water and air, and the contaminated formation 1 is formed by adding a third cleaning medium in addition to water as the first cleaning medium and air as the second cleaning medium. Purification methods and devices have been developed.
[0041]
The fluid 2 is ejected from an injection port 5 provided on a wall surface of the press-in well 3 at a pressure for controlling a physical action, a chemical reaction, and a metabolic function of microorganisms, and penetrates into the contaminated formation 1 to penetrate the contaminated formation 1. After stirring and washing, the contaminants 6 are separated from the contaminated formation 1. 60-210 L (liter) / min water pressurized to 20-200 MPa by the ultra-high pressure pump 7 and 300 m pressurized to 0.5-0.5 MPa ³ / H of air constitutes the fluid 2 and the fluid 2 is injected into the injection well 3 by the pressure, thereby achieving the purpose even if the contaminated formation 1 is clay, silt or mudstone. The pressure and amount of the fluid 2 are appropriately set according to the physical properties of the contaminated formation 1, that is, the constituent particles / consolidation degree, the groundwater, and the type of the pollutant 6.
[0042]
In addition, with respect to formation contamination by heavy metals, the contaminants due to heavy metals can be removed by mixing at least one of an ion-exchange substance and an adsorption substance and a solution containing a heavy metal mineral into the fluid as defined in claim 3. A fixed purification treatment can be performed in the contaminated formation. Specifically, at least one of zeolite, allophane, imogolite, activated carbon, and a silicate alumina solution known as a heavy metal mineral forming solution is mixed into the fluid 2 and used. Since these ion-exchange substances and adsorbents have a function of adsorbing harmful substances such as heavy metals, contaminants such as heavy metals are taken into the ion-exchange substances and adsorbents and have the effect of sealing off heavy metal poisons.
[0043]
That is, even in a clay, silt, or mudstone layer which cannot normally penetrate the fluid 2, the fluid 2 is introduced into the contaminated formation 1 in which the tissue is destroyed and loosened by the action of stirring and washing by the ultra-high pressure jet water 20. Can be infiltrated. Further, in the case of VOCs formation contamination, etc., purifying the fluid 2 is promoted by controlling the physical action and the chemical reaction or the metabolic function of microorganisms, or by injecting the fluid 2 at a pressure at which the above-mentioned air sparsing effect is exhibited.
The term “solution containing a heavy metal mineral” defined in claim 3 refers to an alumina silicate solution or the like.
[0044]
A high-pressure delivery pipe of the ultrahigh-pressure pump 7 is hermetically connected to the injection hole 30 located in the above-ground portion of the injection well 3. The pressure of the ultrahigh-pressure pump 7 and the components contained in the fluid 2 can be appropriately adjusted by a control panel (not shown) or the like. In addition, the rod 31 of the metal pipe inside the press-fit well 3 is well-known for boring, and the injection port 5 is rotated with the drilling rotation of the rod 31 with the injection port 5, and the sprinkler action causes The effect of stirring and washing the high-pressure jet water 20 is enhanced.
[0045]
Then, the contaminant 6 is removed by collecting the fluid 2 containing a component that has not been detoxified from the contaminant 6 from the collection well 4. Ultra-high pressure jet water 20 is injected from the injection port 5 opened in the underground side wall of the rod 31 of the injection well 3 to stir and wash the contaminated geological formation 1, thereby purifying and cleaning by physical action and chemical reaction and metabolism of microorganisms. Support and control functions. Here, the contaminants 6 are removed from the contaminated stratum 1 by collecting the fluid 2 containing the components that have not been detoxified out of the contaminants 6 from the collection well 4, and the harmful substances are removed by ground equipment (FIG. 4) described later. And harmless substances can be separated.
[0046]
In addition, since VOCs are hard to volatilize with respect to VOCs existing in water in the contaminated formation 1 under the groundwater table, only the shallower area of the contaminated formation 1 than the groundwater table is purified. There was a waste that everything could not be used effectively. Therefore, there is contaminated groundwater 22 in the contaminated geological formation 1, there is no air in the saturated region below the normal groundwater level 22a, and when the two-phase fluid 2 is injected from the injection well 3, the pressure of the gas injects the well. The purification function can be exerted on the unsaturated region centered at 3 and down to the depressed groundwater level 22b. In other words, by injecting the fluid into the contaminated formation and the contaminated groundwater at a high pressure and washing the water, the water level of the contaminated groundwater is pushed down to a deeper level, so that the VOCs contaminated formation that has been submerged before purification is also exposed to air. In other words, purification can be performed more efficiently at a lower level, over a wider area.
[0047]
FIG. 2 is a schematic sectional view of a contaminated formation 1 suitable for the present embodiment. A well-known methane-utilizing bacterium 21 inhabits the formation containing methane gas, and the metabolism of the methane-utilizing bacterium 21 renders the harmful substances 6 present in the contaminated formation 1 including the contaminated soil 10 on the surface layer harmless. Not only the methane assimilating bacteria 21 but also certain microorganisms are known to detoxify the harmful substances 6 by metabolism. For example, a method of purifying breeding water by adding a certain microorganism to the breeding water of an aquarium (not shown) for breeding tropical fish, etc. A method of detoxifying the pollutant 6 is well known, and the principle of purification is the same.
[0048]
In addition, it is obvious that human beings can live in good health because the global-scale natural purification system including methane-utilizing bacteria 21 and other microorganisms and animal and plant ecosystems is functioning normally. The gist of the present invention is that the natural purification system on a large scale is limited to the local contaminated geological formation 1 and the purification is efficiently performed.
[0049]
Here, the fluid 2 is pressurized by the ultrahigh pressure pump 7 (see FIG. 1) to a pressure that appropriately controls the metabolic function of the methane assimilating bacteria 21, and penetrates the contaminated stratum 1 from the injection well 3 as ultrahigh pressure jet water 20. The contaminated formation 1 is agitated, sprayed and permeated to support the growth and metabolism of the methane assimilating bacteria 21 to increase the purification efficiency. The pressure of the ultra-high pressure jet water 20 means "the pressure which controls any function of the physical action and chemical reaction of the fluid, and the metabolism and promotion of microorganisms and the function of high-pressure washing" as defined in claim 1.
[0050]
In FIG. 2, the contaminated groundwater 22 contained in the contaminated geological formation 1 is recovered by the recovery well 4 and circulated as it is in the fluid 2 as the cleaning medium. Although the fact that the contaminated groundwater 22 contains the natural methane-utilizing bacteria 21 is used as it is, if the natural methane-utilizing bacteria 21 are insufficient, the methane-utilizing bacteria 21 are artificially added to the fluid 2. May be added. Further, a gas or nutrient that promotes the growth of the methane assimilating bacteria 21 to promote metabolism may be added to the fluid 2. FIG. 2 shows a configuration in which the natural purification system already provided in the natural state is limited to the local contaminated stratum 1, and the purification is accelerated and efficiently carried out. A known means for promoting the above is added for practical use.
[0051]
Hereinafter, an embodiment related to bioaugmentation that can obtain public acceptance will be described.
Here, the "first step of injecting the fluid from the injection well under the condition of maintaining the metabolic activity of the microorganism and the second step of purifying the contaminated stratum by the metabolism of the microorganism" defined in claim 12 are described. The grounds for execution are as follows.
For methane assimilating bacteria, the high pressure injection of 100 MPa or more reduced the growth ability and the activity of the enzyme responsible for the decomposition of pollutants and the activity of methane oxidase, indicating that the condition for maintaining metabolic activity was 40 MPa. . At a high-pressure injection of 350 MPa or more and a hydrostatic pressure of 400 MPa or more, a remarkable decrease in the growth ability of methane assimilating bacteria and a remarkable decrease in the activities of the enzymes responsible for the decomposition of pollutants and methane oxidase were observed.
Therefore, if high pressure injection of methane assimilating bacteria is performed at a pressure of 40 MPa or less, the conditions for maintaining the metabolic activity of the microorganisms are satisfied, and the first and second stages of injecting the fluid from the injection well are performed. Can be executed.
[0052]
Next, after the purification of the contaminated geological formation is completed in the second step, in the “third step of injecting the fluid from the injection well by switching to conditions for killing the microorganisms”, Is the condition for killing. If the high pressure injection is performed at a pressure of 400 MPa or more, the third stage can be performed because most of the methane assimilating bacteria are killed. It should be noted that other methods that have not been established at present may be used as long as they are “conditions that kill the microorganism without causing secondary contamination”.
[0053]
Further, the fluid recovered from the recovery well is included therein, as defined in claim 13, "the condition for killing the microorganism is realized by ultra-high pressure injection exceeding the living condition of the microorganism." After switching to the ultra-high pressure injection setting of a pressure of 400 MPa or more at which the methane assimilating bacteria are killed, re-injection is performed from the injection well.
[0054]
By conducting bioaugmentation in this way, there is no concern about adverse effects on ecosystems, and public acceptance is obtained.
In addition, the object can be achieved within the range of an extension of the technique and equipment related to the in-situ contaminated formation cleaning method and the apparatus using the ultra-high pressure injection.
[0055]
It is difficult to volatilize VOCs with respect to VOCs existing in the water in the contaminated formation 1 deeper than the water surface of the groundwater, but cleaning is performed by injecting ultra-high pressure water 20 containing air around the injection well 3. By doing so, the contaminated geological formation 1 is stirred into flakes, and the water level of the contaminated groundwater 22 is lowered to a deeper level as shown by the groundwater level 22b which has been pressed down at high pressure.
Therefore, VOCs that could not be volatilized by being submerged in groundwater before being purified are also exposed to the air, and can be more efficiently purified to a deeper depth and in a wider area.
[0056]
FIG. 3 is a schematic diagram showing the arrangement of the injection well 3 and the recovery well 4. The press-fit well 3 and the recovery well 4 are formed from the ground 100 by drilling (boring, etc.) at appropriate intervals. The injection well 30 and the recovery well 4 have respective injection holes 30 and extraction holes 40 connected to the ground, and are connected to ground equipment (not shown) (see FIG. 4). Further, the distance from the injection port 5 provided on the wall surface or the bottom of the rod 31 (see FIGS. 1 and 4) of the metal tube constituting the press-fit well 3 to the absorption port 8 provided on the wall surface or the bottom of the recovery well 4. D is set in the range of 0.5 to 5.0 m. The distance D is appropriately adjusted depending on the permeability of the fluid 2 to the contaminated formation 1. That is, the distance D is long and the pressure of the fluid 2 is relatively low in a sand layer having good permeability. Conversely, in the case of a low-permeability clay, silt or mudstone stratum, the distance D is short and the pressure of the fluid 2 is set to be considerably high.
[0057]
If the fluid 2 is water and air, each of them is supplied to the injection port 5 in a pressurized state, and is formed into a nozzle shape (not shown) that is appropriately mixed at the injection port 5 to include bubbles. Since the super-high-pressure jet water 20 (FIGS. 1 and 2) is generated, there is a stratum destruction effect accompanied by a sparging phenomenon, and a high cleaning effect is exerted even on a clay, silt or mudstone stratum with poor permeability.
[0058]
The absorption port 8 provided on the wall surface of the metal tube constituting the recovery well 4 forms a screen (filter shown in FIG. 8) 47 by a large number of slit holes having a width of 2 mm and a length of 150 mm as an example. If the pressure difference before and after the screen 47, that is, if the outside of the metal tube is at a high pressure and the inside is at a low pressure, the fluid 2 can pass through, and the clogging prevention sand 44 (see FIG. 8) prevents unnecessary earth and sand from entering the recovery well 4. Therefore, the well does not become unusable by filling up the inside of the well. It is desirable that the form of the screen be appropriately selected depending on the state of the stratum.
[0059]
FIG. 4 is a schematic diagram showing a plant configuration. The plant is configured at the location of the contaminated stratum 1, and when the purpose of purification is achieved, the plant is removed, moved to another site, and repeatedly used by the plant. It is a plant. Hereinafter, the configuration, operation, and effect will be described together.
[0060]
The press-in well 3 and the recovery well 4 are drilled by a boring device 50 using a metal tube. As described with reference to FIG. 1, the rod 31 that forms the press-fit well 3 by a metal pipe rotates in the ground under the ground, and is sprinkled by the ultra-high-pressure water 20 injected from the injection hole 5 in the ground. 1 to give the effect of stirring and washing.
Although the boring device 50 is connected only to the injection well 3, the boring device 50 is also connected to the recovery well 4 in the same manner so that it can be used for observation, recovery, and injection. Drilled. The rod 31 is required to be rotated only when it is used as the press-fitting well 3 so that the boring device 50 is connected and driven. The boring device 50 is removed from the well.
[0061]
The collection well 4 is connected to a collection mother pipe 41 via a valve 42 which can be switched and connected without opening the extraction hole 40 on the ground. If a measuring instrument (not shown) is connected, the degree of contamination can be measured. You can also. The collection mother pipe 41 is sucked by the vacuum pump 51 to pump the fluid 2 collected from the plurality of collection wells 4 without leakage into a notch tank 52 with a lid (not shown in FIG. 4). Among the contaminated water into which the contaminant 6 (FIG. 1) is taken in by the cleaning action and the fluid 2 containing the contaminant gas such as VOCs, the contaminant 6 is settled in the two-tank notch tank 52 for the contaminated water. Can also be removed. After the contaminant 6 is roughly settled in the first tank, the supernatant flowing from the first tank through the V-shaped notch is collected in the second tank and settled similarly, and the supernatant of the second tank is aerated. It may be sent to the device 53. In that case, it is more effective to add an appropriate precipitant to the notch tank 52. In the notch tank 52, the flow rate of the liquid passing through the V-shaped notch is measured at the water level of the notch, and the aqueous solution containing harmful substances such as VOCs is continuously sent to the aeration device 53, and is rendered harmless by the aeration device 53. It is processed. The harmful gas containing VOCs and the like separated by the aeration device 53 at the time of the detoxification treatment is released to the atmosphere after being detoxified by the activated carbon adsorption tower 55. In the case of VOCs contamination or the like, the water detoxified by the aeration device 53 is temporarily stored in a two-tank water tank 54 and is used for circulation.
The sedimentation treatment in which the contaminant 6 is settled and removed in the two-tank notch tank 52 or a sedimentation treatment having a higher purification action can be performed in the two-tank water tank 54.
[0062]
The water temporarily accumulated in the water tank 54 and secured in an amount necessary for continuing the continuous work was pressurized to about 200 Mpa by the ultra-high pressure pump 7 and simultaneously pressurized to about 0.5 Mpa by the ultra-high pressure pump 7. Fluid 2 mixed with air and having a high level of potential energy is injected through an injection hole 30 located above the injection well 3 via a boring device 50. Then, the fuel is injected into the contaminated formation 1 from the injection port 5 opened in the underground side wall of the injection well 3. At the injection port 5, water and air are supplied to the injection port 5 in a pressurized state, and are appropriately mixed by a nozzle (not shown) of the injection port 5, thereby producing a high-pressure cleaning effect. Here, the first washing medium is water, the second washing medium is air, and the third washing medium is at least one of an ion exchange substance and an adsorbing substance and a heavy metal mineral forming solution. It may be mixed.
[0063]
The ultrahigh-pressure water jet 20 containing air bubbles generated in this way exerts a considerable stratum destruction action and a cleaning effect on the contaminated formation 1 by a combination of the sparging phenomenon and the sprinkler action. Therefore, a high cleaning effect is exerted even on the contaminated formation layer 1 of clay, silt or mudstone having poor permeability. In particular, the injected ultrahigh-pressure jet water 20 and the sparged compressed air come into contact with the contaminants 6 dissolved in the water or the contaminants 6 adsorbed on the soil particles. It has been confirmed that it has the effect of vaporizing from soil and soil particles to separate and escape.
[0064]
Furthermore, because of the high-pressure condition, the unsaturated zone expands due to the drop in the groundwater level in the saturated zone, and the range in which the pollution can be purified increases. That is, since VOCs and the like cannot be volatilized in a state of being immersed in the groundwater, the VOCs and the like are exposed to air and vaporized by depressing the groundwater in the contaminated geological formation 1 under high-pressure conditions, and thus can be efficiently purified. .
[0065]
Next, the operation will be described.
FIG. 5 is a flowchart showing the order of execution of the method for purifying the contaminated formation 1. First, in step S1 for destroying the stratum, the stratum organization is destroyed even for the contaminated stratum 1 of clay, silt or mudstone by the ultra-high pressure water jet 20 injected from the injection port 5 of the injection well 3, and the permeability is reduced. And the fluid 2 is permeated in the state of the ultra-high pressure jet water 20. Here, the water pressure is 20 to 200 MPa, and the air 300 m pressurized to about 0.5 to 0.7 Mpa ³ / H is effective. However, even if it is possible to inject a water pressure exceeding 400 MPa in a plant that has been put into practical use in consideration of economic effects, even if it requires a large amount of cost to forcibly reinforce special equipment, it is necessary to use the contaminated stratum 1 At this stage, it has been confirmed that the destruction effect of the steel does not increase.
[0066]
As an example of obtaining a good result, when the ultrahigh-pressure jet water 20 is injected into the contaminated formation 1 from the jet port 5 at a flow rate of 20 to 30 L (liter) / min, a saturated zone is artificially formed (S2). . The fluid 2 saturated in the unsaturated zone is removed from the saturated zone artificially by securing an escape route by the amount additionally injected. If the absorption port 8 of the recovery well 4 is open in the formed saturated zone, the fluid 2 in the saturation zone seeks an outlet at the absorption port 8 and from there passes through the recovery well 4 to contaminate the pollutants. 6 and is discharged to the surface of the earth, so that it is recovered from the formed saturated zone. There is a distance D of about 2 m from the injection port 5 to the absorption port 8, and the contaminated formation 1 is purified before the fluid 2 passes this distance D. The distance D is adjusted depending on the physical properties of the contaminated formation 1 and the type of the contaminant 6, and is appropriately set in the range of 0.5 to 5.0 m.
[0067]
The fluid 2 that has moved from the absorption port 8 to the recovery well 4 is pumped (S3) in the recovery well 4 that extends vertically to the ground as bubbles rise. Further, the collection mother pipe 41 connecting the plurality of collection wells 4 on the ground is sucked by the vacuum pump 51 (FIG. 4). Under ultra-high pressure purification, there is also an operation of pumping (S3) the high-pressure fluid 2 formed in the unsaturated zone in the contaminated formation 1 from the recovery well 4. The pressure difference between the negative pressure and the ultra-high pressure of the vacuum pump 51 promotes the volatilization of volatile substances in the contaminated formation 1, so that there is an effect of collecting all residual VOCs and the like from the contaminated formation 1.
[0068]
The fluid 2 containing VOCs collected from the fluid suction port of the vacuum pump 51 is aerated (S4) in the aeration tank 53, and separated into a gas containing VOCs and water from which VOCs has been removed. Here, since the pollutants are only VOCs, if it is determined that the fluid 2 has been completely detoxified, the fluid 2 may be released and drained (S7). If it is determined that the use of the fluid 2 is more advantageous, the fluid 2 is circulated and reused as the cleaning medium (S8). For example, the detoxified water is temporarily stored in the water tank 54, and is re-injected into the injection well 3 by the ultra-high pressure pump 7.
[0069]
If heavy water is contained in the water from which VOCs have been removed, detoxification processing is performed in accordance with the type of heavy metal (S5). The detoxification process (S5) is a technique that has already been established, and further description will be omitted.
[0070]
On the other hand, when the fluid 2 containing VOCs is aerated (S4) by the aeration device 53, the toxic gas containing VOCs separated from the fluid 2 is toxic in the activated carbon adsorption tower 55 so as not to cause air pollution. The components are adsorbed and removed, detoxified (S6), and then released into the atmosphere (S7).
[0071]
In the construction order shown in the flow chart of FIG. 5, it is not specified to inject a fluid having a purification function by any of physical action and chemical reaction, and metabolism and promotion of microorganisms and high-pressure washing. This assumes the case of the contaminated formation 1 previously containing methane assimilating bacteria shown in FIG. 2, and it is assumed that the fluid 2 already has a purification function by metabolism of microorganisms.
[0072]
Here, specific examples of substances that constitute the “physical action and chemical reaction, and the purification function by any of metabolism and promotion of microorganisms and high-pressure washing” defined in claim 1 will be specifically exemplified. The nutrient sources of anaerobic methanogens different from the methane-utilizing bacteria mentioned above are the growth nutrients of methanogens represented by lactic acid, methanol, ethanol, acetic acid, citric acid, pyruvate, polypeptone, etc. Any nutrient commonly known as
[0073]
In addition, as a growth nutrient of sulfate-reducing microorganisms, nutrients generally known as growth nutrients of sulfate-reducing microorganisms represented by lactic acid, methanol, ethanol, acetic acid, citric acid, pyruvic acid, polypeptone, sugar-containing organic substances, and the like. Is fine. Furthermore, organic wastewater / waste that is the subject of methane fermentation is effective as a growth nutrient for heterotrophic anaerobic microorganisms, such as brewery wastewater, starch wastewater, dairy wastewater, and sugarmaking wastewater. And beer lees, okara, and sludge.
[0074]
As the inorganic reducing agent to be added to the fluid 2, for example, from the group consisting of reduced iron, cast iron, iron-silicon alloy, titanium alloy, zinc alloy, manganese alloy, aluminum alloy, magnesium alloy, calcium alloy and their water-soluble compounds It is good to choose at least one. In the presence of such a reducing agent, reductive halogenation by a combination of physical action, chemical reaction and microorganism can be promoted.
[0075]
The reducing agent preferably contains a large amount of reduced iron or cast iron. Alternatively, the reducing agent is an iron-silicon alloy, a titanium-silicon alloy, a titanium-aluminum alloy, a zinc-aluminum alloy, a manganese-magnesium alloy, an aluminum-zinc-calcium alloy, an aluminum-tin alloy, an aluminum-silicon alloy, magnesium It is preferably at least one selected from the group consisting of a manganese alloy and a calcium-silicon alloy.
[0076]
The reducing agent may be a salt composed of an organic acid or hypophosphorous acid and iron, titanium, zinc, manganese, aluminum or magnesium.
Further, the reducing agent is preferably a water-soluble compound since the main component of the fluid 2 as the purification medium is often water.
[0077]
In order to appropriately adjust the amount of the reducing agent depending on the state of the pollutant 6, a preliminary test should be performed on site to determine the additive concentration individually in accordance with the site conditions.
Further, the substance mixed into the fluid 2 does not need to be limited to the reducing agent, and an oxidizing agent is also effective, but a specific description thereof will be omitted.
[0078]
FIG. 6 is a plan view showing the arrangement of a plurality of wells and the rotation thereof. FIG. 7 is a flowchart showing a construction order taking into account the rotation of the well.
With reference to FIGS. 6 and 7, a brief description will be given of a rotation in which the press-fit well 3 and the recovery well 4 are appropriately exchanged roles.
[0079]
First, wells are drilled in a grid pattern in the order of A, B, C to W, X, and Y at intervals of 2 m on the ground which is assumed to be the contaminated formation 1 (S11). At this stage, by performing sampling survey of the contaminated formation 1 using each of the wells A to Y as observation wells, formation contamination diagnosis can be performed. After drilling up to the well Y in the center of the contaminated area, the well Y is used as the injection well 3 (S12). At this time, in the boring device 50, the high pressure jet water 20 is replaced with a rod 31 capable of press-fitting from a drilling rod (not shown) and connected to the delivery pipe of the ultrahigh pressure pump 7.
[0080]
In FIG. 6, wells A to X other than Y are used as recovery wells 4 (S13). The details will be described later with reference to FIG. A measuring device is connected to the extraction hole 40 of the recovery well 4, and the components, concentration, distribution, and the like of the pollutant 6 are measured by the extracted fluid 2 in each of the wells A to X (S14). The purification method can be optimally set according to the measurement results.
[0081]
The wells Q, R, S, T, U, V, W, and X in the immediate vicinity of the press-fit well Y are used as the recovery well 4 (S15). However, a typical method is merely illustrated for explaining the rotation.
[0082]
Next, the injection well 3 is rotated from Y to X (S16). Then, the wells P, Q, R, Y, V, W, N, and O in the immediate vicinity of the injection well X are used as the recovery well 4 (S17).
[0083]
Further, the injection well 3 is rotated to X, W, V, U, T, S, R, and Q (S18). If the predetermined function is executed in the injection well Q and the recovery wells A, B, C, R, Y, X, O, and P corresponding to the injection well Q, the incomplete purification is performed according to the above-described measurement result. The recovery well at the point is used as a press-in well, and purification is proceeded in the same manner (S19). Further, the degree of achievement of purification can be confirmed based on the above-described measurement results (S20). If not achieved, complete purification can be achieved by repeating the rotation and confirmation of S12 to S20.
[0084]
FIG. 8 is a diagram mainly showing the details of the recovery well pipe, in which (a) an estimated columnar schematic diagram, (b) a cross-sectional view, (c) an enlarged view of a screen, and (d) an arrangement diagram of slits constituting the screen. is there.
[0085]
As shown in the columnar estimation schematic diagram of FIG. 8A, when the range of 14 to 42 m underground is the contaminated stratum 1 and the geological condition is different from that of the non-contaminated stratum 9, as shown in FIG. A metal tube 43 is inserted vertically into the well. On the outer periphery of the metal tube 43, fine holes formed by slits 48 shown in FIGS. 8C and 8D constitute an absorption port 8 having a function of a screen 47 (FIG. 3). The screen 47 is set on a metal tube 43 extending from 42 to 11 m below the ground. A gap between the outer periphery of the metal tube 43 and the inner wall of the well is filled with silica sand 2 as clogging prevention sand 44. Then, the contaminated stratum 1 and the surface of the ground are kept airtight by filling the water-impervious seal 45 under the ground 11 to 10 m. Backfill from 1m underground to the surface with backfill soil 46.
[0086]
When the ground surface is covered with an air packer (airtight lid) (not shown) or a leveling concrete having a thickness of about 30 cm for the same purpose as the water-blocking seal 45, the fluid 2 does not leak. So effective.
[0087]
The metal tube 43 inserted vertically into the well shown in FIG. 8B can be pulled up as needed. Therefore, in order to realize the rotation of the well shown in FIG. 6, the recovery well 4 is switched to the injection well 3, and vice versa. At that time, the degree of purification achievement was observed in each well, and if it was determined that purification of heavy metal contamination had not been achieved, the wells and / or the wells where it was determined that contaminants due to heavy metal remained. A nearby well is filled with an ion exchange material and an adsorbent.
Although omitted in FIGS. 7 and 8, the ion-exchange substance and the adsorbed substance are obtained by pouring a powder or a granular substance into the metal tube 43 from the ground and filling the lower part of the well. The metal tube 43 may be removed from the ground, or another method may be used.
[0088]
As specific ion exchange substances and adsorption substances, zeolite, allophane, imogolite and activated carbon are used. Since these ion-exchange substances and adsorbents have a function of adsorbing harmful substances such as heavy metals, contaminants such as heavy metals are taken into the ion-exchange substances and adsorbents and have the effect of sealing off heavy metal poisons. With this configuration, even when a method of injecting the fluid from one well and recovering the fluid from the other well is used, it is possible to purify the contaminated formation in a wide range at a high level without unevenness. In addition, heavy metals can be fixed and purified in the contaminated formation.
[0089]
Then, the equipment arrangement on the ground shown in FIG. 4 also corresponds to the procedure shown in FIG. 5 to FIG. After the contaminated geological formation 1 is completely purified in this way, all the plants are removed and the wells are backfilled to complete the process.
The contaminants due to heavy metals are taken into the ion exchange material and the adsorbed material, and seal off the poisons of heavy metals. That is, in the case of a heavy metal or the like, it is not eluted by fixing the mineral.
[0090]
【The invention's effect】
As described above, according to the invention of claim 1, the pollutant entangled in fine-grained clay, silt or mudstone can be separated from any of the functions of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing. Detoxification can be achieved while controlling to a suitable state.
[0091]
According to the second aspect of the present invention, a wide range of contaminated geological formations can be purified at a high level without unevenness. In addition, heavy metals can be fixed and purified in the contaminated formation.
[0092]
According to the third aspect of the present invention, it is possible to fix and purify pollutants caused by heavy metals in the contaminated formation.
[0093]
According to the invention according to claim 4, the liquid pressurized in the range of 20 to 500 MPa heats the clay or silt or mudstone even in the clay or silt or mudstone contaminated formation where the fluid hardly penetrates. It can be broken, penetrated, stirred, and washed. Further, if the gas is pressurized in the range of 0.1 to 1.0 MPa, the gas is mixed with the groundwater in the formation and becomes fine bubbles by sparging, and the effect of stirring and washing is enhanced, and the bubbles are not dispersed. Since the treatment contaminants are lifted toward the ground together with the liquid, it is easy to perform the detoxification treatment.
[0094]
According to the fifth aspect of the present invention, by decompressing the contaminated stratum around the recovery well, volatile contaminants are volatilized from the contaminated stratum, thereby facilitating detoxification.
[0095]
According to the invention according to claim 6, when the total amount of the fluid used is reduced, the chemical substance or the microorganism for maintaining any of the physical action, the chemical reaction, the metabolism of the microorganism, and the high-pressure washing is used. Costs can be saved because the amount used is also reduced. Further, if the fluid is circulated in a closed loop, it is difficult to diffuse secondary environmental pollution.
[0096]
According to the invention of claim 7, purification can be performed efficiently with a small number of wells.
[0097]
According to the eighth, ninth, and tenth aspects of the present invention, the efficiency can be increased by using existing purification equipment and technologies. In other words, by using existing purification equipment and technologies together, limited management resources can be efficiently used so that the burden on those who pursue the polluted environment, which is positioned as a global social emergency, can be reduced. It can operate, purify contaminated strata, and protect the global environment.
[0098]
In particular, according to the ninth aspect of the present invention, by injecting the fluid at a high pressure into the contaminated formation, the water level of the contaminated groundwater is pushed down to a deeper level. In this case, the air is exposed to the air, so that the water can be purified to a deeper depth, in a wider area, and more efficiently.
[0099]
According to the eleventh aspect, costs can be reduced. In addition, if the fluid is circulated in a closed loop, secondary environmental pollution is not easily diffused.
[0100]
According to the invention of claim 12, microorganisms selected from a single type or a limited type are ground at an unusually high concentration that is impossible in a normal ecosystem so as to meet the purpose of purifying the contaminated stratum. Even if the bioaugmentation injecting into is carried out, there is no secondary contamination in which the microorganisms grow abnormally and there is no fear of adversely affecting the ecosystem, so that public acceptance is obtained.
[0101]
According to the invention of claim 13, since the condition for killing the microorganism is realized by the ultra-high pressure injection exceeding the survival condition of the microorganism, the in-situ contaminated stratum purification method using the ultra-high pressure injection is used. The purpose can be achieved within the range of the technology or equipment related to the device or on an extension thereof.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a contaminated stratum illustrating a basic embodiment of the present invention.
FIG. 2 is a schematic sectional view of a contaminated formation suitable for the present embodiment.
FIG. 3 is a schematic diagram showing an arrangement of a press-in well and a recovery well.
FIG. 4 is a schematic diagram showing a plant configuration.
FIG. 5 is a flowchart showing an execution order of a method of purifying the contaminated formation 1;
FIG. 6 is a plan view showing the arrangement of a plurality of wells and their rotation.
FIG. 7 is a flowchart showing a construction order in consideration of well rotation.
FIGS. 8A and 8B are diagrams mainly showing details of a recovery well tube, in which FIG. 8A is a schematic diagram of an estimated column shape, FIG. 8B is a sectional view, FIG. 8C is an enlarged view of a screen, and FIG.
[Sign]
1 Contaminated stratum
2 fluid
3 injection well
4 Collection well
5 injection port
6 pollutants
7 Ultra high pressure pump
8 Absorption port
10 Contaminated soil
11 clay layer
20 Super high pressure water injection
21 Methane-utilizing bacteria
22 Contaminated groundwater
22a Normal groundwater level
22b Depressed groundwater level
30 Injection hole
31 rod
40 extraction holes
42 valve
43 metal tube
44 Sand for preventing clogging
45 impermeable seal
46 Backfill soil
47 screen
48 slit
49 Bottom lid
50 boring equipment
51 vacuum pump
52 Notch tank
53 Aeration device
54 aquarium
55 activated carbon adsorption tower
100 ground
D Distance from injection port 5 to absorption port 8

Claims (13)

In the contaminated formation, forming a press-in well for injecting a fluid having a purification function by either physical action and chemical reaction, and metabolism and promotion of microorganisms and high-pressure washing,
Injecting the fluid at a pressure that controls one of the functions of physical action, chemical reaction, metabolism of microorganisms, and high-pressure washing from an injection port provided on the wall surface or the bottom of the injection well, and the injected fluid is Stirring and washing in the stratum, separating or decomposing contaminants,
A method for purifying a contaminated formation, wherein the contaminant is removed by collecting a fluid containing undecomposed contaminants in the formation from a collection well. The press-fitting wells for recovering the fluid having the purification function and the injection wells capable of vertically moving the injection port are formed by drilling at appropriate intervals,
The injection well and the recovery well exchange the roles of injection and recovery by appropriate rotation,
The method according to claim 1, wherein the wells determined to have the contaminants due to heavy metals and / or the wells near the wells are filled with an ion exchange material and an adsorbent material. The method according to claim 1 or 2, wherein at least one of an ion exchange material, an adsorbent, and a heavy metal mineral forming solution is mixed into the fluid. A liquid pressurized to a range of 20 to 500 MPa and / or a gas pressurized to a range of 0.1 to 1.0 MPa as the fluid is injected into the injection well. Item 4. The method for purifying a contaminated geological formation according to any one of Items 3. The method according to any one of claims 1 to 4, wherein the fluid is sucked from the recovery well by a negative pressure pump. The detoxification treatment of the fluid collected from the collection well, and a part or all of the detoxification-processed fluid is circulated and used. 3. A method for purifying a contaminated stratum according to item 1. The distance from the absorption port provided on the wall surface or the bottom of the recovery well to the injection port through the contaminated formation is set in a range of 0.5 to 5.0 m. Item 7. The method for purifying a contaminated formation according to any one of Items 6. The step of detoxifying the fluid recovered from the recovery well includes a contaminant adsorption step and / or an aeration step using activated carbon, any one of claims 1 to 7. The method for cleaning a contaminated geological formation according to item 1. The method according to any one of claims 1 to 8, wherein the fluid is sprayed onto the contaminated formation and the contaminated groundwater at a high pressure for cleaning. An apparatus used for the method for purifying a contaminated formation according to any one of claims 1 to 9,
A contaminated formation purifying apparatus, comprising: means for detoxifying the fluid, the means for adsorbing contaminants with activated carbon and / or the means for aeration. The apparatus for purifying a contaminated formation according to claim 10, further comprising a fluid storage tank for circulating and using part or all of the fluid. A first step of injecting the fluid from the injection well under conditions that maintain metabolic activity of the microorganism;
A second step of purifying the contaminated stratum by metabolism of the microorganism;
3. The method according to claim 1, further comprising: after the purification of the contaminated geological formation is completed in the second step, switching to a condition for killing the microorganisms and injecting the fluid from the injection well. The method of purifying a contaminated formation according to any one of claims 9 to 9. The method for purifying a contaminated formation according to any one of claims 1 to 9, wherein the condition for killing the microorganism is realized by an ultra-high pressure injection that exceeds the survival condition of the microorganism.

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