JPH08224566A - Environment repair and soil treatment using bacteria - Google Patents

Abstract

PURPOSE: To efficiently repair polluted soil by bacteria. 8W CONSTITUTION: This method for repairing soil polluted with a contaminant by introducing at least one of bacteria decomposing the contaminant, a nutritive substance for bacteria decomposing the contaminant and an inducing substance developing the decomposition capacity of bacteria decomposing the contaminant into the polluted soil has a process controlling the coefficient of water permeation of soil so as to uniformly distribute the substance introduced into polluted soil throughout the soil region to be repaired. Further, a soil treatment method has a process preparing the soil region to be repaired having the soil polluted with the contaminant so that the distribution of the coefficient of water permeability has a plurality of the max. values and a process controlling the coefficient of water permeability of the soil so that the max. value having the substantially min. coefficient of water permeability shows the max. ratio.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for repairing contaminated soil with microorganisms and a method for treating soil.

[0002]

2. Description of the Related Art With the rapid progress of science and technology, human beings have enjoyed a blessed living environment in a wide variety of fields such as clothing, food and shelter as well as transportation and communication means. On the other hand, exhaust gas from fossil fuels, artificial chemical raw materials, and chemical products have gradually eroded the global-level natural environment that extends to the air-water terrestrial sphere.
Among them, the land area is the place where human beings live, and is therefore most affected by pollution. Considering that water circulates in the air-water terrestrial area, environmental pollution in the terrestrial area is a serious problem that spreads to the global level. Examples of well-known soil (land) pollutants include hydrocarbons such as gasoline, halogenated hydrocarbons such as PCB, teratogenic pesticides such as dioxins, and radioactive compounds. In particular, organic compounds are used in large quantities as automobile fuels, cleaning solvents for precision parts, solvents for dry cleaning, and chemicals for insecticidal and weeding purposes, and soil contamination by these compounds is still in progress. Furthermore, it was pointed out that some of the polluted organic compounds had strong carcinogenicity, and it was revealed that they exert a very serious influence on the living world. Therefore, soil contamination by organic compounds has become an issue to be solved immediately.

As a method of repairing soil contaminated with organic compounds, a method of excavating the contaminated soil and heat treatment, a method of vacuum extraction in the contaminated soil, or a method of utilizing microorganisms capable of decomposing pollutants And so on. Heat treatment methods can almost completely remove pollutants from soil. However, since soil excavation is required, it is difficult to perform purification treatment under a building, and because the cost required for excavation and heat treatment is relatively high, it is also difficult to apply to the purification of a wide range of contaminated soil. The vacuum extraction method is an inexpensive and simple purification method. However, since it takes a long time to remove low-concentration pollution, it is mainly effective for cleaning high-concentration pollution. The microbial purification method has the feature that it is easy to clean under a building because it is not necessary to excavate contaminated soil, and low-concentration organic compounds can be purified in a short time by using microorganisms with high decomposition activity. Therefore, it is currently attracting attention as an environmentally friendly purification method.

Conventionally, methods for purifying soil contamination by microorganisms are divided into methods that utilize indigenous bacteria that originally inhabit the soil and methods that utilize alien bacteria that do not inhabit the soil. In the former case, nutrients, inducers, oxygen, or other chemicals to enhance decomposition activity are injected into the soil,
Purify. In the latter case, the foreign bacteria are injected into the soil, and the step of injecting nutrients and the like to enhance the decomposition activity is performed. In such a method for purifying contaminated soil using microorganisms, it is desired to maintain high decomposition activity by microorganisms in a wide range of soil areas for a long time, but at least with the current microbial control technology, this can be achieved. Have difficulty. Rather, the method of limiting the soil area to be rehabilitated and controlling the degrading activity of microorganisms in this area can be an overall efficient soil remediation method including rehabilitation cost, rehabilitation period and safety.

US as a prior art relating to the above-mentioned technology
P 5,133,625 describes a method of controlling an injection pressure by measuring an injection pressure, a flow rate and a temperature using an extendable injection pipe. This method controls the concentration of microorganisms, the concentration of nutrients and the like by the injection pressure to maintain the degrading activity of the microorganisms optimally, and is mainly aimed at controlling the purification process by the microorganisms.

USP 4,442,895 and US
P5,032,042 is for injecting gas or liquid into the soil under pressure from the injection well to crack the soil (crush the soil), and at that time, it can also supply oxygen and nutrients necessary for microbial purification. Is stated. However, this method is intended to crack as extensively as possible and is not intended to limit the repair area.

US Pat. No. 5,111,883 describes a method of injecting a chemical solution into a predetermined region in the horizontal and vertical directions of soil depending on the relative positions of the injection well and the extraction well. This is aimed at injecting a chemical solution to a predetermined position in the soil by a geometric method, and it is considered to be an extremely effective method for limiting the repair area even in microbial purification, but the equipment configuration is complicated. It has the drawback that

In order to inject a microorganism or a substance for maintaining degrading activity into a limited area from an injection well, an impermeable layer is formed at a soil position at a predetermined distance from the injection well, and this is used as a barrier wall for the injection area. A method of limiting
Conventionally, as a method of forming such an impermeable layer, a plastic sheet is laid in the ground, a method of providing an asphalt layer, or cement, water glass, urethane,
A method of injecting a treatment agent such as acrylamide or acrylate into the soil is known. Japanese Patent (Japanese Patent Publication 2-2
6662 and 5-27676) describe a method of forming an impermeable layer at a predetermined position in soil by using a water-soluble polymer which is insolubilized by ions in soil.
This method limits the mass transfer by using the impermeable layer as a barrier, and can be a technique for limiting the injection area even in the step of injecting microorganisms and nutrients into the soil.
However, burial of plastic sheets and formation of asphalt layers require excavation and backfilling of soil, which is incompatible with the intention of soil restoration by microorganisms. In addition, in the method of injecting a treatment agent such as cement or a water-soluble polymer,
A large number of treatment agent injection wells are required to form a complete barrier wall, which is difficult to apply to economical soil remediation by microorganisms.

When microorganisms or the like are injected into the soil from the outside, it is difficult to evenly distribute the injected microorganisms or the like in the soil to be repaired even if the above technique is used.

Therefore, in order to sufficiently repair the contaminated soil, it is necessary to inject an excessive amount of microorganisms or the like so that the pollutant in the portion where the injected substance is most difficult to be distributed is decomposed in the soil region to be repaired, This will increase the cost of soil remediation.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the microorganisms and substances injected into the soil region to be repaired are evenly distributed in the soil region to efficiently and sufficiently soil. It is an object of the present invention to provide a soil restoration method capable of performing restoration.

Another object of the present invention is to provide a soil treatment method capable of evenly distributing a substance in the soil region when the substance is injected into the soil region.

[0013]

The method for repairing contaminated soil according to the present invention comprises a microorganism that decomposes the pollutant in soil polluted by the pollutant, a nutrient for the microorganism that decomposes the pollutant, In a method of repairing the soil with a microorganism by introducing at least one of an inducer capable of expressing the ability of a microorganism to decompose the pollutant, the material introduced into the soil is uniformly distributed in a soil region to be repaired. To control the hydraulic conductivity of the soil.

The method for repairing contaminated soil according to the present invention is a method for repairing contaminated soil by using microorganisms, and the distribution of hydraulic conductivity has a plurality of maximum values and is contaminated with pollutants. A step of preparing a soil region to be repaired having an existing soil; a step of controlling the hydraulic conductivity of the soil so that a maximum value having a substantially minimum hydraulic conductivity shows a maximum ratio in the hydraulic conductivity distribution of the soil And at least one of a microorganism that decomposes the pollutant in a soil having a controlled hydraulic conductivity, a nutrient substance of the microorganism that decomposes the pollutant, and an inducer for expressing the pollutant decomposition ability of the microorganism that decomposes the pollutant. It is characterized in that it comprises a step of supplying one to remediate the contaminated soil.

Further, the method for treating soil according to the present invention comprises the step of preparing a soil region to be repaired, which has a soil having a plurality of maximum values of hydraulic conductivity and is contaminated with pollutants;
And in the distribution of hydraulic conductivity of the soil, the method has a step of controlling the hydraulic conductivity of the soil so that a maximum value having a substantially minimum hydraulic conductivity exhibits a maximum ratio.

That is, as a result of various examinations by the applicant regarding the above problems, the distribution of the substance injected into the soil in the soil depends on the liquid permeability of the soil, that is, the hydraulic conductivity, and The present invention is based on the finding that the uneven distribution of the substance injected into the soil in the soil is based on various hydraulic conductivity of the soil.

According to the invention, the contaminated soil can be repaired extremely efficiently.

Further, according to the present invention, since the degree of diffusion of the injected substance can be controlled, it is possible to prevent the injected substance from diffusing to the soil region where repair is not necessary and disturbing the ecosystem there.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

First, when a solution of microorganisms and nutrients is injected into the soil under pressure, the injection range is generally determined by the hydraulic conductivity of the soil. However, since the hydraulic conductivity of soil usually has a very large anisotropy, the injected solution is not evenly distributed, but is actively distributed in the direction of large hydraulic conductivity in soil. Therefore, the hydraulic conductivity of the repaired soil is made uniform in advance, and then a solution containing microorganisms and nutrients is injected. As the soil hydraulic conductivity, the saturated hydraulic conductivity obtained by the constant water level method or the variable water level method, the Piezometer method, the Tube method, and the Auger
-Hole method, or Dry Auger-hole
On-site hydraulic conductivity or unsaturated hydraulic conductivity obtained by the method can be used.

The following two methods are mainly considered for adjusting the hydraulic conductivity of the restored soil.

The first is a method of increasing the hydraulic conductivity of a soil portion having a small hydraulic conductivity in the soil area to be restored, and the second is a reduction of the hydraulic conductivity of a soil portion having a large hydraulic conductivity in the soil area to be restored. It is a method to let.

In the present invention, it is preferable to use the second method described above. This is because it is easy to control the diffusion of the substance injected into the soil in the soil, and it is possible to suppress the diffusion into an unpredictable region, for example.

Specifically, for example, when the hydraulic conductivity distribution of the soil in the soil region to be repaired has a plurality of maximum values as shown in FIG. 1, it is substantially minimum in FIG. Permeability coefficient (in Fig. 1, the center value is about 3.0 x 10 ^-3 cm /
It is preferable to control the hydraulic conductivity of the soil so that the maximum value having s) has the maximum ratio as shown in FIG. 2 in the hydraulic conductivity distribution.

That is, the injected substance can be uniformly distributed in the soil region by adjusting the hydraulic conductivity of the soil portion in which the injected substance is most difficult to diffuse in the soil region to be repaired.

The above-mentioned "maximum value having substantially the minimum hydraulic conductivity" means, for example, a plurality of maximum values having a significant ratio obtained when the hydraulic conductivity distribution of the soil in the soil region to be restored is taken. Refers to the maximum value with the smallest hydraulic conductivity.

For example, even if a soil part having a very low hydraulic conductivity exists in the contaminated soil region to be repaired, and even if it is detected as the maximum value in the hydraulic conductivity distribution measurement, the ratio of the soil part to the entire soil region is very small. If so, contamination of such soil parts is virtually non-issue. That is, it cannot be said that the hydraulic conductivity of such a soil portion has a significant ratio in the hydraulic conductivity distribution of the soil region.

[0028] Specifically, what proportion has a significant proportion depends on the degree of restoration required, but for example, when the hydraulic conductivity distribution is taken, the total proportion is 10
% Or more, especially 8% or more, or even 5% or more, the maximum value having the minimum hydraulic conductivity is treated as "the maximum value having the substantially minimum hydraulic conductivity" and repaired. It is preferable since the injected substance can be more uniformly distributed in the soil region to be filled.

As a concrete method for controlling the hydraulic conductivity, when a dispersion in which particles are suspended is injected into the soil, these fluids are inevitably introduced into a soil portion having a high hydraulic conductivity. At this time, the voids in the soil are filled with the injected particles, and the hydraulic conductivity decreases. Therefore, the permeability of the soil part with a large permeability before injection decreases after injection,
The soil has a uniform hydraulic conductivity as a whole. Microbial soil restoration is efficient after this step. That is, when a microorganism or a substance for maintaining degrading activity is injected into this soil, the injected substance is evenly distributed from the injection well because the hydraulic conductivity of the soil is almost uniform. Further, since the injection distance (arrival distance) from the injection well is substantially determined by the total injection volume of the injection material, the injection time, the injection pressure, the injection flow rate, etc., it becomes possible to inject into a limited region.

When the suspended particles are injected from the injection well to make the hydraulic conductivity uniform, particles having a uniform particle diameter or particles having different particle diameters can be used. When particles with the same particle size are suspended and injected, the optimum particle size is determined by the hydraulic conductivity of the soil to which the injection process is applied. Usually, the particle size of the injected particles is selected from the range of 1 μm to ³ mm. For example, in soil having a water permeability of 1 × 10 ⁻³ cms ⁻¹ , 10 μm to 1 mm.
Particles of about 100 μm are preferably used. Furthermore, for soils with a low hydraulic conductivity, it is effective to use particles with a smaller particle size, because the average pore size will also be smaller. On the other hand, since soil is extremely heterogeneous and has a wide distribution of pore diameters, a method of injecting particles having different particle diameters simultaneously or sequentially is also useful. That is, filling large voids in the soil with mainly large particles,
The resulting small voids and the small voids originally present in the soil are filled with smaller particles to achieve a soil with a uniform hydraulic conductivity as a whole. The particle size of the particles injected at this time is in the range of 1 μm to 3 mm,
For example, in soil having a water permeability of 1 × 10 ⁻³ cms ⁻¹ , particles having a particle size of about 10 μm to 1 mm are distributed, and preferably particles having a particle size of about 100 μm or less are used. Furthermore, for soils with a low hydraulic conductivity, the average pore size is also small, so it is effective to use particles with a smaller particle size distribution.

As the particles to be injected, various solids and gels which have been used up to now in the chemical industry, pharmaceutical industry, food industry or wastewater treatment system can be used.
For example, sized sand or soil, porous glass, ceramics, metal oxides, activated carbon, kaolinite, bentonite, zeolite, silica gel, alumina, anthracite, particles such as cement, starch, agar, chitin, chitosan, polyvinyl alcohol. , Algin, gel particles such as polyacrylamide, carrageenan, agarose, gelatin, water glass, cellulose, glutaraldehyde, polyacrylic acid, polyurethane, polyester,
Natural or synthetic polymers such as polyvinylpyrrolidone and N-vinyl-2-pyrrolidone are used. These particles have an appropriate particle size distribution and are mainly suspended in water or an aqueous polymer solution and then injected. Furthermore, it is possible to inject mixtures of the abovementioned particles.

After the soil water permeability is made uniform by the above steps, the soil can be efficiently restored by injecting microorganisms or nutrients necessary for maintaining the decomposition activity thereof. That is, when the injected substance is injected into the pretreated soil, the permeability coefficient of the soil is almost uniform, so the injected substance is evenly distributed from the injection well, and at this time, the total injection volume, injection time, injection pressure, or injection flow rate, etc. It can be injected into a limited area by adjusting.

As the substance to be injected here, for example, when an indigenous microorganism is used for decomposing a pollutant, the nutrient required for growth and reproduction of the microorganism and the ability of the microorganism to decompose the pollutant are expressed. At least one of the inducers is included.

When an exogenous microorganism is used for decomposing the pollutant, at least one of the microorganism or the nutrient and the inducer of the microorganism and the microorganism may be added to the soil.

The present invention will be described below with reference to examples, but these do not limit the scope of the present invention.

In each of the following examples and comparative examples, the hydraulic conductivity is a constant head perm based on the German Industrial Society Standard JSF T311-1990.
This is due to miability.

Example 1 A dispersion in which particles having the same particle size are suspended is poured into soil.
Method to make uniform water permeability Coarse sand with an average particle size of 1 mm, fine sand with an average particle size of 0.5 mm,
And fine sand with silt having an average particle diameter of 0.1 mm was roughly mixed and filled in an acrylic container having a length of 1 m, a width of 1 m, and a height of 1 m. Next, the hydraulic conductivity at five soil positions around the inlet in this container was measured.

Then, a stainless steel injection pipe having an outer diameter of 10 mm and an inner diameter of 8 mm was inserted into the soil from the center of the surface of the container so that one end thereof was located at a depth of 50 cm from the soil surface. The other end of this injection pipe is connected to a liquid feeding pump via a valve, and the injection solution in the tank can be pressure-fed to the inlet by this liquid feeding pump.

Fine sand was sized to select particles having an average particle size of about 0.1 mm. Next, 250 g of these particles were suspended in 5 liters of water, and were pressure-fed at a flow rate of 1 liter / min by a liquid-sending pump while stirring so that the particles would not settle. After the injection, the soil around the inlet was sampled (5 points) and the hydraulic conductivity thereof was determined.

Table 1 shows the average and standard deviation of soil hydraulic conductivity before and after the injection treatment. From this, it was found that by injecting a dispersion in which particles having the same particle size were suspended into the soil, the hydraulic conductivity of the soil having a wide distribution can be reduced and uniformized (the standard deviation can be reduced).

(Example 2) A dispersion prepared by suspending particles having different particle sizes was poured into soil.
Method for making the water permeability uniform As in Example 1, the test soil was filled in an acrylic container, and an injection pipe and a liquid feed pump were provided.

Fine sand was sized to select particles having an average particle size of about 10 μm, about 20 μm, about 50 μm, and about 100 μm. Next, 60 g of these particles were suspended in 1.25 liters of water, respectively, and the particles were sequentially fed at a flow rate of 1 liter / min by a liquid-sending pump in descending order of average particle size while stirring so that the particles would not settle. After the injection, the soil around the inlet was sampled (5 points) and the hydraulic conductivity thereof was determined.

Table 1 shows the average value and the standard deviation of the soil hydraulic conductivity before and after the injection treatment. From this, it was found that by sequentially injecting the dispersions in which the particles having different particle diameters are suspended into the soil, the wide permeability coefficient of the soil can be reduced as a whole and the soil can be made uniform (the standard deviation can be reduced).

In addition, the effect of equalizing the water permeability is the same as in Example 1.
I also found it to be better.

[0045]

[Table 1]

(Example 3) A dispersion in which particles having the same particle size are suspended is poured into soil.
Method to make uniform water permeability Coarse sand (average particle size 1 mm) is laid in a thickness of 30 cm in an acrylic container 1 m long, 1 m wide, and 1 m high, and then fine sand (average particle size 0.5 mm) of 40 cm It was spread to a thickness, and finally, fine sand (average particle size 0.1 mm) was spread to a thickness of 30 cm to prepare a model test soil similar to an actual soil having various hydraulic conductivity. Next, the hydraulic conductivity distribution of the soil was obtained. Figure 1 shows the hydraulic conductivity distribution in the soil region of this example.

Next, the stainless steel injection pipe having an outer diameter of 10 mm and an inner diameter of 8 mm was inserted into the soil in the acrylic container so that the tip of the injection pipe was 50 cm deep from the top soil. The other side of the injection pipe is connected to a liquid feed pump via a valve, and the liquid injected in the tank can be pressure-fed to the inlet by this liquid feed pump.

Next, fine sand is sized so that the average particle size is about 0.1 m.
Particles of m were selected, 250 g of the particles were suspended in 5 liters of water, and the suspension was pressure-fed at a flow rate of 1 liter per minute with a liquid-sending pump while stirring so that the particles would not settle. After the injection, the permeability distribution of the soil region was obtained again. The result is shown in Figure 2.
Shown in

In FIG. 1, the maximum having the minimum hydraulic conductivity (the value at the center of the peak is about 3.0 × 10 ⁻³ cm / s) has the maximum ratio of the hydraulic conductivity distribution in FIG. 2. The hydraulic conductivity was controlled as shown.

(Example 4) A dispersion prepared by suspending particles having different particle sizes was poured into soil.
Method for homogenizing water permeability The acrylic test container was filled with the model test soil in the same manner as in Example 3, and then the container was provided with an injection pipe and a liquid feeding pump in the same manner as in Example 3.

Fine sand was sized to select particles having an average particle size of about 10 μm, about 20 μm, about 50 μm, and about 100 μm. Next, 60 g of these particles were suspended in 1.25 liters of water, respectively, and the particles were sequentially fed at a flow rate of 1 liter / min by a liquid-sending pump in descending order of average particle size while stirring so that the particles would not settle. The permeability distribution was measured again. The result is shown in FIG.

As is clear from FIGS. 1 and 3, the minimum hydraulic conductivity (the value at the center of the peak is about 3.5 × 10 ⁻³ cm / s).
The hydraulic conductivity was controlled so that the maximum value having the value of ## EQU1 ## shows the maximum ratio of the hydraulic conductivity distribution after the injection treatment.

(Example 5) Efficiency by microorganisms in a uniform and limited soil area
To create various soil in the same manner as specific soil remediation Example 3 was filled in an acrylic container.

Next, an aqueous trichlorethylene solution was sprayed from the soil surface to prepare a contaminated soil in which the concentration of trichlorethylene was about 10 ppm per 1 g of soil. Next, an injection pipe and a liquid feed pump were provided as in the case of Example 3.

Then, in the same manner as in Example 3, 250 g of particles having an average particle size of about 0.1 mm were suspended in 5 liters of water,
The water permeability was controlled by pressure feeding with a liquid feed pump at a flow rate of 1 liter per minute while stirring so that the particles would not settle. Then, when the permeability distribution was obtained again, as shown in FIG. 2, the permeability was controlled so that the maximum value having substantially the minimum permeability occupies about 40% of the permeability distribution of the soil. .

On the other hand, as a microorganism for decomposing trichlorethylene, Corynebacterium species J1 (Bitechnotechnical Laboratory) deposit number: FERM P-14332)
Were cultured and grown to 10 ⁸ cells / ml. Further, a solution containing 0.1% yeast extract, 0.2% sodium lactate, and 100 ppm phenol was prepared, and oxygen gas was passed through this solution to saturate the oxygen concentration of the solution to prepare an injection substance. Next, the microorganism and the injected substance were mixed at a volume ratio of 1: 1000, and the mixture was injected into the contaminated soil having the controlled water permeability through an injection pipe at a flow rate of 1 liter per minute for 5 minutes to conduct a repair experiment. As a result, after 2 days, the concentration of trichlorethylene in the soil within about 50 cm from the tip of the injection pipe decreased to about 1 ppm. On the other hand, it was found that the trichlorethylene concentration at the soil position about 80 cm from the tip of the injection pipe hardly changed to about 10 ppm, and only the uniform and limited area from the injection position was efficiently purified.

(Comparative Example 1) Soil restoration was carried out in substantially the same manner as in Example 3 except that the permeability coefficient was not controlled.

As a result, the concentration of trichlorethylene within about 50 cm from the tip of the injection pipe inserted into the soil was about 1 to 10 ppm depending on the soil position, and the place where trichlorethylene was decomposed was decomposed. Not where there was in the soil area. That is, the distribution of microorganisms was uneven.

[0059]

As described above, according to one embodiment of the present invention, effective repair of contaminated soil can be achieved by adjusting the hydraulic conductivity of the target region to be uniform prior to the repair of contaminated soil. It will be possible.

According to one embodiment of the present invention, the hydraulic conductivity of the soil in the contaminated soil area to be rehabilitated is maximized in the hydraulic conductivity distribution of the soil in the soil area having a substantially minimum hydraulic conductivity. By adjusting the value to show the maximum ratio in the hydraulic conductivity distribution, it is possible to efficiently repair the contaminated soil without the need to inject an excessive amount of microorganisms, nutrients and inducers.

Further, according to this embodiment, since the diffusion of the injected substance from the injection pipe into the soil can be controlled, the leakage of the injected substance to the outside of the soil region to be repaired can be suppressed.

[Brief description of drawings]

FIG. 1 Permeability coefficient distribution map of soil treated in Example 3 before permeability control

FIG. 2 Permeability coefficient distribution map of soil treated in Example 3 after permeability control

FIG. 3 is a hydraulic conductivity distribution map of soil treated in Example 4 before the hydraulic conductivity control.

Claims (9)

[Claims] 1. A microorganism that decomposes a pollutant in soil polluted by the pollutant, a nutrient for the microorganism that decomposes the pollutant, and an inducer that expresses the degradability of the microorganism that decomposes the pollutant. In a method of repairing the soil with a microorganism by introducing at least one of them, the hydraulic conductivity of the soil is controlled so that the substance introduced into the soil is uniformly distributed in the soil region to be repaired. To repair contaminated soil. 2. The method of claim 1, wherein the step of controlling the hydraulic conductivity is the injection of a dispersion of particles in suspension. 3. The method of claim 2, wherein the particles consist of particles of substantially uniform size. 4. The method of claim 2, wherein the particles are of different particle size. 5. The method of claim 4, wherein the implanting is done with large particles before small particles. 6. The method according to claim 2, wherein the particles are solid or gel. 7. The method according to claim 2, wherein the dispersion medium of the dispersion is water. 8. A method for repairing an environment containing contaminated soil by using a microorganism, wherein the repair has soil having a plurality of maximum distributions of hydraulic conductivity and polluted soil. To prepare a proper environment; in the hydraulic conductivity distribution of the soil, controlling the hydraulic conductivity of the soil so that the maximum value having substantially the smallest hydraulic conductivity exhibits the maximum ratio;
And at least one of a microorganism that decomposes the pollutant in soil having a controlled water permeability, a nutrient substance of the microorganism that decomposes the pollutant, and an inducer for expressing the pollutant decomposing ability of the microorganism that decomposes the pollutant. And a method for repairing the contaminated soil, the method comprising repairing the environment. 9. The distribution of hydraulic conductivity has a plurality of maximum values,
And preparing a soil region to be rehabilitated having soil contaminated with pollutants; and in the hydraulic conductivity distribution of the soil such that the maximum with substantially the smallest hydraulic conductivity exhibits the maximum ratio. A method for treating soil, comprising the step of controlling the hydraulic conductivity of the soil.