JP3241236B2 - How to clean contaminated soil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying contaminated soil by decomposing contaminants such as various organic solvents existing in the soil or flowing out of the soil from a production plant or the like.

[0002]

2. Description of the Related Art With the advancement of industry, various organic solvents such as aromatic hydrocarbons, organic chlorinated compounds such as dichloroethylene, trichloroethylene and tetrachloroethylene are used in a production process, and these organic solvents are erroneously used. May escape into soil.

[0003] Some of these organic solvents have little or no effect on the biological environment including the human body. In particular, in the case of the latter organochlorine compound, when it is mixed with groundwater,
It becomes a big social problem.

[0004] A fundamental solution to this situation has not yet been found, (1) a method of removing and replacing contaminated soil, (2) a blockage surrounding the contaminated area to prevent the outflow of organic solvents from the contaminated area. At present, it is dealt with by a simple method such as a method of forming a wall.

[0005] However, in the former method, it is necessary to finally dispose of the contaminated soil, which causes a new environmental problem for the disposal site. On the other hand, in the latter method,
Not only is construction of the barrier wall expensive, but it is not reliable enough to ensure permanent barrier properties.
Moreover, it is not preferable that the contamination state continues in the area.

[0006]

Therefore, in recent years, a biochemical treatment method of decomposing an organic solvent by a microorganism has been studied. In other words, microorganisms having the ability to decompose organic solvents are directly sprayed on the area contaminated by the organic solvent, or a purified solution containing these microorganisms is sprayed from the soil surface, or a supply pipe is buried in the soil, The purification liquid is supplied into the soil through a supply pipe. According to these methods, since the organic solvent in the soil can be directly decomposed in the soil, it is not necessary to remove the contaminated area or to form a barrier.

However, the movement of microorganisms in the soil is extremely slow or the movement range is limited to a very narrow area. Therefore, when the microorganisms or the purified liquid containing the microorganisms is sprayed, the microorganisms may not penetrate deep into the soil or into the target area. Microorganisms disappear. In addition, when the supply pipe is inserted into the soil to supply the purified liquid containing microorganisms, even if the inlet of the supply pipe is positioned so as to match the contaminated area, the injected purified liquid is in the depth direction of the ground. There is a phenomenon in which only a portion where the is loosened is selected, and this is used as a water path, and only that portion penetrates and escapes in a pulsating manner. Therefore, it is extremely difficult to supply microorganisms with a directivity to a target contaminated area, and it is not possible to satisfactorily repair contaminated soil.

Therefore, for example, Japanese Patent Laid-Open No. Hei 6-21215
No. 5 and U.S. Pat.
As shown in the figure, the purified liquid containing microorganisms is supplied from the supply pipe, and the purified liquid is supplied from the supply pipe to the recovery pipe while applying a negative pressure to the collection pipe inserted into the ground parallel to the supply pipe. Although there is a technology to provide directivity by moving it toward, it is necessary to insert both the supply pipe and the recovery pipe into a certain contaminated area, which is not only inefficient in terms of workability, but also Since a pressure difference cannot be ensured unless the interval between the collecting pipe and the collecting pipe is shortened, it is necessary to insert the supplying pipe and the collecting pipe at a number of points in the unit contamination area, which is a factor of reducing workability.

Further, even if the flow of the purified liquid can be generated, it is practically impossible to supply microorganisms to the entire soil volume around the supply pipe because the flow direction is linear.

[0010] Accordingly, a main object of the present invention is to make it possible to reliably inject a purifying liquid containing microorganisms into a target contaminated area and to obtain a substance excellent in workability.

[0011]

According to a method of purifying contaminated soil according to the present invention, which solves the above-mentioned problems, a supply pipe is inserted into a contaminated area of a soil with an inlet facing the inlet, and a main flow path of the supply pipe is inserted. A purification solution containing a microorganism that decomposes the contaminant and a growth condition material that ensures the growth of the purification material, and injecting the purification solution into the contaminated region from an inlet of the supply pipe, The liquid is a liquid having a gel time of 60 seconds or more or exhibiting self-hardening property. As the injection conditions, the injection gauge pressure of the main flow path is more than 1 kg / cm ² and 50 kg / cm ² or less, and the purifying liquid is The injection amount of
The injection rate is 50 liter / min, and the liquid is injected into the contaminated area of the soil from the injection port.

[0012] Here, a guide path projecting 3 to 50 cm in the radial direction with respect to the axis of the supply pipe is formed by sandwiching or surrounding the injection port of the supply pipe in the front-rear direction. Communicate with the main flow path in the pipe,
It has a regulating wall extending in the radial direction with a separation distance of 50 mm, and this guideway space is opened to the ground,
Supplying the purifying liquid to the main flow path, changing the flow direction of the purifying liquid through the inlet and the guide path, and causing the purified liquid to flow out,
It is desirable to inject directionally into the contaminated area of the soil. Further, it is preferable that the guide path is constituted by two guide plates which sandwich the inlet of the supply pipe in the longitudinal direction and are fixed substantially parallel to the supply pipe at the interval.

[0013]

According to the present invention, a supply pipe is inserted into an area of soil contaminated with an organic solvent, and microorganisms that decompose contaminants such as an organic solvent into the supply pipe (hereinafter also referred to as degrading microorganisms).
And a purifying liquid containing a growth condition material for ensuring the growth, and the purifying liquid is supplied to the contaminated region from the inlet of the supply pipe.

When a non-gelling (no gel time) or non-curing liquid is used as the purifying liquid, it is highly likely that the liquid will escape outside the target area during the injection process.
Alternatively, it may be diluted by groundwater after injection, and eventually the degraded microorganisms may escape the contaminated area by riding the flow. Therefore, in the present invention, a liquid having a gel time of 60 seconds or more or having self-hardening properties is used as the purifying liquid. Further, as the injection conditions, the injection gauge pressure of the main flow path is set to more than 1 kg / cm ² and 50 kg / cm ² or less, and the injection amount of the purifying liquid is set to 1 to 50 liter / min. Thus, the purifying liquid can be injected reliably and without escape.

A supply device including a supply pipe having a structure according to the embodiment of the present invention is used, and injection conditions are set within a certain range. As a result, it is possible to inject the purifying liquid with excellent directivity, and thus to inject the purifying liquid only into the target contaminated region without fail. It is not clear why the supply with directivity can be performed, but it is considered as follows. 1 and 2
As shown in (1), the purified liquid PL sent into the main flow path inside the supply pipe 10 is discharged from the inlet 1. At this time, since the purified liquid PL is regulated as a flow in the guide plates 2 and 2 in the vertical direction, it flows out from the open end of the guide plates 2 and 2. In addition, the distance D between the guide plates 2 and 2 is short between the inlet 1 and the open ends of the guide plates 2 and 2, and the purified liquid PL is discharged from the inlet 1 at the stage of discharge.
It is considered that the purified liquid PL flows laminarly, flows out like a plate from the open end of the guide plates 2 and 2 and is supplied to the contaminated area in the ground as it is.

According to the findings of the present inventors, for example, when the contaminant is an organic solvent, a rough portion of soil,
Alternatively, as shown in FIG. 3, at the boundary of the stratum or at the end of the groundwater flow, it often stays as a disc-shaped layer at a certain depth.

As described above, when the supply pipe is inserted into the contaminated soil and the purified liquid containing microorganisms is supplied, even if the injection port of the supply pipe is positioned so as to match the contaminated area, the injected purified liquid is supplied. In this method, only a portion where the ground is loosened in the depth direction is selected, and this is used as a water channel, and only the portion is penetrated and escaped at that portion, and there is a phenomenon that it is difficult to inject the target contaminated area.

Although it is conceivable to inject a surplus of the purifying liquid with respect to the escaped amount, it is not sufficient to inject the purifying liquid into a portion other than the target contaminated area by supplying an excessive purifying liquid. It is necessary to avoid as much as possible because it may disturb the ecosystem in the natural soil. From this aspect, it is desired to inject the purifying solution only at the location where the layered organic solvent stays.

Therefore, it is necessary to supply the purifying liquid with directivity only to the target contaminated area while preventing runaway to different places in the depth direction. Also,
Forming a linear flow of the purifying liquid as described in the above publication is extremely poor in workability for the above-described reason, and therefore it is desirable to inject the purifying liquid in a disk shape at the injection pressure of the purifying liquid itself.

However, according to the embodiment of the present invention, by devising the structure of the supply pipe itself, it is possible to inject the whole of the supply pipe with directivity without installing a separate recovery pipe or the like. In addition, it is possible to reliably inject a purifying liquid containing microorganisms into a target contaminated area, and to achieve excellent workability.

The microorganisms applied to the present invention can be appropriately selected depending on the soil contamination status, especially the type of contaminants, and the growth condition material can also be appropriately selected depending on the microorganism used.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In the present invention, for example, the supply device shown in FIG. 1 can be used. At the tip of the supply pipe 10 or at a position slightly higher than the tip, the outlet of the main flow path of the purified liquid PL of the supply pipe 10, that is, the inlet 1 is connected. The two guide plates 2, 2 are integrated with the supply pipe 10 with the guide plate 2,
A guideway is formed between the two. In this integration, in addition to welding, it can be mechanically fixed with an appropriate structure.

As shown in FIG. 3, for example, as shown in FIG. 3, the supply device 10 connects the supply pipe 10 to the inlet 1 of the soil E containing the contaminated area Z0 which is spread horizontally in a plate shape. Into the contaminated area Z0. Thereafter, as shown in FIG. 5, the purified liquid PL is supplied from a supply port communicating with the main flow path of the supply pipe 10, and is injected from the injection port 1 into the contaminated region Z0 through the main flow path. Purified liquid PL injected into soil
Penetrates through the permeation injection region Z including the contaminated region Z0. Thus, pollutant-decomposing microorganisms can be efficiently supplied to the entire contaminated area Z0, and contaminated soil can be reliably purified.

On the other hand, even when the cleaning solution is simultaneously injected at a plurality of points because the contaminated region covers a wide area, as shown in FIG. Even if the purifying liquid is simultaneously injected into the different positions in the depth direction from the supply pipes 10 and 10,
In order to show the directivity of the injection mode from the ground, that is, since the injection mode does not escape to other places in the depth direction, the penetration injection zones Z and Z do not interfere with each other. Injection experiments were carried out with a mold experiment facility filled with porous soil, and a phenolic colorant was added to the cleaning solution in advance,
It has been confirmed from the result of disassembling the mold after the injection and visually observing the injection state in the filling body. This is, on the contrary, a proof that according to the present invention, it is possible to perform osmotic injection with directivity of the purified liquid.

The supply device of the present invention can be inserted into a hole drilled by another drilling device, and can also have its own drilling function. For this reason, as shown in FIG. A drilling blade 11 having drilling bits 11a, 11a,.

At the time of pouring, first, as shown in FIG. 7, while supplying the drilling water W through the swivel 12, the drilling device is drilled to a predetermined depth by the supply device having the drilling function as shown in FIG. Make a hole.

Next, as shown in FIG. 8, a quick-setting grout Gf having a gel time of 30 seconds or less, a main agent A ₁ made of, for example, water glass and an appropriate curing agent B ₁ are supplied through a swivel 12, and the inlet 1 It is injected into the surrounding ground without being merged in the vicinity to fill the space inside the drill hole H.

Thereafter, as shown in FIG.
More preferably, a purifying solution composed of a gellable material (gel time is preferably 2 minutes or more),
The main agent A ₂ and the hardener B ₂ are supplied through the swivel 12 and the main channel independent of each other, and are injected into the surrounding ground without being merged near the inlet 1. As a result, as described above, the purified liquid PL is injected into the ground with directivity, and does not escape to another depth position. At this time, since the solidified compact of the instantaneous setting grout Gf previously filled is in the borehole H, it is prevented from flowing to the ground side, which is more preferable. Since the solidified body of the instantaneous grout Gf between the guide plates 2 and 2 is broken or extruded, there is no problem in the injection of the cleaning liquid PL.

Then, as shown in FIG. 10, after the supply device is pulled up to another upper contaminated region Z0, the purified liquid PL is injected on the upper stage. Such operations are sequentially repeated.

On the other hand, it is also possible to perform directional permeation injection according to another embodiment shown in FIGS. In this example, as shown in FIG. 16, a guide plate 20 made of a flexible material, for example, rubber, is fixed to a lower portion of the supply pipe 10. In the guide panel 20, the inner ends of the upper and lower regulating walls 20A and 20B are fixed at positions sandwiching the inlet 10E, and a bulged portion 20C is formed inward from the outer end in a U-shaped vertical section. At the same time, the opening 20D is formed continuously or intermittently in the circumferential direction in the bulging portion 20C.

As shown in FIG. 17, the supply pipe 10 is composed of an outer pipe 10A and an inner pipe 10B, and supplies air, water, etc. from above and below the discharge port 10C of the inner pipe 10B. Packer 10D, 1 that expands and contracts due to fluid pressure
0D is provided, the inner tube 10B can be moved up and down in the outer tube 10A, and the inner tube 10B is formed at a position corresponding to a certain inlet 10E among the plurality of inlets 10E, 10E,. With the packers 10D, 10D expanded, the grout material is discharged from the discharge port 10C, and the guide board 2 is discharged from the injection port 10E.
The one that is sent out within 0 can be adopted.

At the time of concrete construction, first, as shown in FIG. Thereafter, as shown in FIG.
For example, a cement bentonite-based sleeve grout SG is injected through the supply pipe 10 in the process of lifting the casing 13 or in the same manner as the injection of the purifying liquid described later.

Next, as shown in FIG.
The supply pipe 10 in which 0, 20,... Are fixed at a predetermined pitch is erected in the borehole H and the sleeve grout SG.

Next, as shown in FIG.
In a state where D and 10D are contracted, for example, water is supplied to the inner pipe 10.
B and is discharged from the discharge port 10C. The discharged water flows out of each inlet 10E, 10E,.
Are injected into the ground through 0,20. At this time, the swelling portion 20C of the guide panel 20 serves as a barrier for water flow due to the outflow pressure of the water as shown in FIG. Thus, the state shown by the virtual line in FIG.

In this state, for example, as shown in FIGS. 15 to 17, the inner pipe 10B is placed at the position of the guide board 20 at the lowermost end.
And the packers 10D, 10D
After swelling, the purifying liquid PL is discharged from the discharge port 10C, sent out from the injection port 10E to the guide path in the guide panel 20, and permeated and injected into the surrounding ground through the opening 20D.

After the injection at that stage is completed, the supply pipe 10 is moved to a target stage corresponding to the contaminated area Z0, and the injection is performed there. In this example and the above-described example, the injection stage is changed by a so-called step-up method, but the stage can be moved by an appropriate method such as a descending method.

FIG. 18 shows a case where directivity is given in the vertical direction. As the guide body 200 used here, in addition to the above-mentioned guide plates 2 and 2, a guide board 20 or the like can be used.

In the present invention, a guide path is formed which projects radially from the outlet of the main flow path of the supply pipe by 3 to 50 cm.
However, it is not necessary to always protrude, and this guideway
When the feed pipe is not protruding from the feed pipe upon insertion into the ground, or as shown representatively in FIG.
The projecting distance may be short, and the guiding path may be projected by an external operation from the ground (in the example of FIG. 16, press-fitting of water) at the time of injection or during the injection preparation process, and the projection distance may be maintained.

As an example of the former, as shown in FIG.
A concave portion 40 is formed on the outer surface of the supply pipe 10, and open / close plates 41A and 41B are provided in the concave portion 40 with the inlet 1 interposed therebetween. The open / close plates 41A and 41B are connected to an operation rod 42 having a rack at the lower end from the ground. Is moved up and down to rotate the pinion 43 meshing with it, and by this rotation, the driven gears 44A and 44B are rotated to open and close the open / close plates 41A and 41A.
When B is expanded and contracted, it is accommodated in the concave portion 40 when it is expanded, and when it is contracted, it can be made to project outward.

In the present invention, there are several injection conditions for penetrating and injecting the purified liquid with directivity. The first is
The guide path protrudes from the outlet of the main flow path in a radial direction by a distance L of 3 to 50 cm. When the distance is less than 3 cm, it has been found that the directivity effect of the present invention is small.
When the distance exceeds cm, there is a limit in terms of workability in which insertion into the ground becomes difficult.

Second, the guideway is set to have a separation distance D of 2 mm to 50 mm.
mm. If the interval is shorter than 2 mm, the flow rate will be high, and it will be difficult to inject slowly. 50
If it exceeds mm, the effect of restricting the flow will be reduced, and the flow will be easily diffused.

Thirdly, a liquid which does not gel (has no gel time) or does not harden may be used as a purifying liquid. In this case, although it is related to the target ground, it does not escape to the target area during the injection process. It is likely to disperse, or may be diluted by groundwater after injection and eventually get on the stream and escape degrading microorganisms outside the contaminated area.

Therefore, those having a gel time of 60 seconds or more, particularly 2 minutes or more, or exhibiting self-hardening property are preferred. Shorter gel times or shorter cure times increase the likelihood. As a purifying solution with a gel time of 2 minutes or more,
Water glass is used as a main component, and an acid-based curing agent or the like can be used for this. Even a suspension type injection material using ultrafine particles other than the water glass type, for example, a material using fine particle cement or blast furnace slag fine powder can be permeated and injected, which solidifies without causing a gelling phenomenon. In any case, depending on the gelling material or hardening material to be used, the decomposed microorganism and the growth condition material are appropriately selected depending on the gelling material or the hardened material to be used, based on the viability of the decomposed microorganism, whether to be added to the main agent or the hardener. can do. In addition, since the gelation or curing time is long, the base material and the curing agent can be independently supplied from the storage tank and merged inside the supply pipe, or can be merged before entering the supply pipe.

Fourth, the purified liquid is supplied at a pressure of ² to 50 kg / cm ² (more preferably, 4 to 25 kg / cm ² ) at the injection gauge pressure of the main flow path.
m ² ), and the injection rate is 2 to 50 liters / minute (more preferably, 5 to 25 liters / minute). If the injection pressure is low, injection into the ground itself is difficult. If it exceeds 50 kg / cm ² , the ground will be disturbed, and it will not be possible to perform permeation injection. This is also true for the implant dose.

[0045] In the present invention, the decomposed microorganisms added to the cleaning solution to repair the contaminated soil can be appropriately selected depending on the contaminants present in the contaminated soil. These are not particularly limited, for example, Pseudomona
s, Methylosinus, Methylomonas, Methylobacterium,
Alcaligenes, Mycobacterium, Nitrosomonas, Xantho
monas, Spirillum, Vibrio, Bacterium, Achromobac
ter, Acinetobacter, Flavobacterium, Chromobacteri
um, Desulfovibrio, Desulfotomaculum, Micrococcus
, Sarcina, Bacillus, Streptomyces, Nocardia, Cor
ynebacterium, Pseudobacterium, Arthrobacter, Brev
ibacterium, Saccharomyces, Lactobacillus, Escher
ichia Coli, Methylocystis, Staphylococcus, Nitoro
A microorganism belonging to each genus of sonomas, or a known organic solvent-degrading microorganism such as an acid-producing bacterium or a methane-producing bacterium can be used. These may be used in combination of two or more.

In particular, Pseudomonas puti belonging to the genus Pseudomonas
The da SH-2992 bacterium has the resolving power for toluene, an organic solvent that has been conventionally considered difficult to decompose, and has excellent resistance to benzene.

As these degrading microorganisms, those which have already been isolated, those which have been newly screened from soil or the like depending on the purpose, can be used, and a mixture of a plurality of strains may be used. In the case of separation by screening, it may be unidentified.

The growth conditions for these microorganisms can be appropriately selected depending on the decomposing microorganism used. Examples include inorganic substances such as carbon, nitrogen, and phosphorus, cellulose, lignin, starch, agarose, dextran, albumin, chitin, chitosan, filter paper, wood chips, and a culture solution suitable for the growth of each microorganism. Specific examples of the carbon source include monosaccharides such as glucose and fructose, disaccharides such as sucrose and maltose, organic acids such as citric acid and lactic acid, and alcohols.
In addition, carbon dioxide can be used as a carbon source. Also,
As the nitrogen source, inorganic nitrogen such as ammonia, nitrate and nitrite, or organic nitrogen such as amino acid can be used. These may function not only as a carrier for carrying microorganisms but also as a nutrient source.

The growth condition material is 0.1 to 0.1% in the purified solution.
About 5.0% can be added. In the case where other inorganic substances are required, in order of increasing required ratio, F
e, Ca, Mg, K, Na, Cl, Mn, Zn, B, M
o, I, and Sr. In addition, some microorganisms may require trace elements such as vitamin B group as growth factors.

Further, as a nutrient source, there may be mentioned a mixture of a vegetable protein obtained from soybeans, corn, etc., a degradation product of an animal protein obtained from milk, meat, etc., a mixture of peptides and amino acids, and a nitrogen source. In addition, extracts from animals and plants or microorganisms such as meat extracts, malt extracts, and yeast extracts are used as extracts. These may contain amino acids, peptides, vitamins, organic acids, salts, and the like. In addition, as other additives, body fluids such as blood and serum, plant exudates, antibacterial agents, pigments, and the like can be used. These enhance the selectivity for a specific bacterium or have a growth promoting effect. Naturally, it is also possible to use a mixture of these at an appropriate mixing ratio according to the type of microorganism added to the purification solution.

Other nutrients such as microorganisms obtained by drying and consolidating microorganisms obtained in nature or by cultivation to remove water in the intercellular space and to fix and combine the microorganisms, thinning materials, waste materials and other chips And natural polymers such as lignocellulosic agricultural and forestry wastes such as bagasse and straw, shrimp and crab shell shells and squid spine and other chitin-based marine wastes, and their explosion-treated products. .

As an example of these, Table 1 shows specific combinations of some of the organic solvent-degrading microorganisms and their growth condition materials depending on the case where the organic solvent is an organic chlorine compound. This is shown for reference.

[0053]

[Table 1]

Since the present invention is directed to injecting into the soil or the ground, as described above, the main agent is water glass from the viewpoint of excellent gelation in the ground and safety to the soil. desired.

The present invention can be applied to the case where the cause of the contamination is caused not only by the organic solvent but also by other contamination factors.

[0056]

As described above, according to the present invention, a purified solution containing microorganisms can be reliably injected into a target contaminated area, and the workability is excellent.

[Brief description of the drawings]

FIG. 1 is a perspective view of a supply pipe according to the present invention.

FIG. 2 is a front view thereof.

FIG. 3 is a conceptual diagram showing a contaminated region of an organic solvent in soil.

FIG. 4 is a diagram showing a state where a supply pipe is inserted into soil.

FIG. 5 is a diagram showing a state in which a cleaning liquid is supplied from a supply pipe.

FIG. 6 is a schematic diagram showing an injection state at two locations.

FIG. 7 is a schematic diagram of a first stage of a first construction example.

FIG. 8 is a schematic diagram of a second stage.

FIG. 9 is a schematic diagram of a third stage.

FIG. 10 is a schematic view of an injection state in another stage.

FIG. 11 is a schematic diagram of a first stage of a second construction example.

FIG. 12 is a schematic diagram of a second stage.

FIG. 13 is a schematic diagram of a third stage.

FIG. 14 is a schematic diagram of a fourth stage.

FIG. 15 is a schematic diagram of a fifth stage.

FIG. 16 is a schematic perspective view of another example of the supply device.

FIG. 17 is an explanatory diagram of the inside thereof.

FIG. 18 is a schematic perspective view of another supply device.

FIG. 19 is a schematic front view of still another supply device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Injection port, 2 ... Guide plate, 10 ... Supply pipe, 200 ... Guide body, D ... Separation distance, L ... Projection length, E ... Soil, Z0 ... Contaminated area, Z ... Purified liquid supply area, PL ... Supply liquid .

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B09C 1/00-1/10 E02D 3/12-3/12 103

Claims (3)

(57) [Claims] 1. A supply pipe is inserted with an inlet facing a contaminated area in soil, and a microorganism that decomposes the contaminant is provided in a main flow path of the supply pipe, and a growth condition material that ensures the growth of the microorganism. And supplying the purification liquid containing the purification liquid to the contaminated region from the inlet of the supply pipe, the purification liquid is a liquid having a gel time of 60 seconds or more or exhibiting self-hardening, As the injection conditions, the injection gauge pressure in the main flow path is set to more than 1 kg / cm ² and 50 kg / cm ²
A method for purifying contaminated soil, comprising: injecting the purifying liquid into a contaminated region of the soil through the inlet at a rate of 1 to 50 L / min. 2. An injection port of the supply pipe is sandwiched or surrounded by the front and rear, and is radially 3 to 50 with respect to the axis of the supply pipe.
a guide path protruding from the supply pipe and communicating the guide path with a main flow path in the supply pipe, the guide path having a regulating wall extending in a radial direction at a distance of 2 to 50 mm, and The guideway space is opened to the ground, the purified liquid is supplied to the main flow path, the flow direction of the purified liquid is changed through the inlet and the guideway, and the clarified liquid flows out to the soil contaminated area with directivity. The method for purifying contaminated soil according to claim 1, wherein the soil is injected. 3. The contaminated soil according to claim 2, wherein the guide path is constituted by two guide plates which sandwich the inlet of the supply pipe in the longitudinal direction and are fixed substantially in parallel with the supply pipe at the interval. Purification method.