JPH08192137A - Soil purification method and apparatus - Google Patents

Abstract

PURPOSE: To provide a soil purification method and apparatus which can purify soil effectively at an original position. CONSTITUTION: An excavation hole is dug so as to over the depth from the ground surfaces to a polluted area CA in which soil G containing pollutants exists, and a purifying agent J for decomposing the pollutants is injected into the soil G, CA containing the pollutants through an injection monitor M placed in the hole, and the depth of the monitor M is changed while being rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus capable of purifying a region of soil contaminated with petroleum hydrocarbons or the like without displacing its position.

[0002]

2. Description of the Related Art Contamination of soil with heavy metals such as cadmium, lead and zinc has been a major problem in Japan (soil contamination with heavy metals is treated by a physical method). , Petroleum pollutants,
Contamination with tar-based pollutants and other organic matter has become a problem.

Such soil pollution directly causes growth inhibition of plants and growth inhibition of organisms (including microorganisms) in soil. In addition, when pollutants are dissolved in water (including groundwater), water is polluted, and when pollutants are volatilized and diffused into the atmosphere, they cause air pollution, which adversely affects the human body (health). . Further, by being absorbed by the agricultural products, pollutants are accumulated in the agricultural products and the livestock that ate the agricultural products, thereby contaminating the environment in a complex manner. In particular, pollutants existing deep in the ground may be gradually leached into the groundwater and moved over a wide range, and the above-described damage may occur over a wide range.

For such soil pollution, conventionally, an incineration method in which pollutants are taken out together with soil and incinerated in an incinerator, a contaminated area is enclosed by a wall such as concrete, and confined, or pollution Immobilization / stabilization method of pouring solidified material into the area to solidify and stabilize the area, soil washing method of excavating and removing contaminated soil and washing with water, chemicals, etc. Bioremediation, in which pollutants in the soil are decomposed by microorganisms, or by directly injecting microorganisms into the contaminated soil,
It was treated by digging a well at the polluted site and extracting it from the volatile harmful organic substances by a soil air extraction method.

[0005]

However, in the case of the incineration method, it is possible to generate more harmful compounds as a result of incineration of organic pollutants, as in the case of incineration of organic chlorine compounds to generate dioxins. is there. In the case of the immobilization / stabilization method, it is necessary to monitor the contaminants over time so that the contaminants do not leak or leak after the treatment. In addition, since the pollutants remain as they are, they are not applicable to the treatment for which safety is permanent. In the case of the soil cleaning method, there is a problem that wastewater treatment after cleaning must be performed and it is unsuitable for treating a large amount of contaminated soil. In the case of bioremediation, there are problems that the ecosystem is changed due to the dominant breeding of organisms or microorganisms that selectively decompose pollutants, and that the repair period is long. The soil air extraction method can only be applied to volatile pollutants. Moreover, there is a possibility that secondary contamination may occur because the contaminants are not separated but decomposed.

Further, when the ground or soil is contaminated by harmful substances or pollutants, the locations are as follows: on the premises of a cleaning plant, on the premises of a semiconductor or other manufacturing plant, on the premises of an energy plant using fossil fuels, petrochemicals. Most are directly under the building, such as on the factory grounds, or on the premises of operating equipment such as a waste treatment plant, or in the surrounding area. Therefore, it is impossible to adopt a treatment method such as an incineration method or a soil cleaning method that involves a step of excavating and removing contaminated soil. For the same reason, a treatment method that requires a step of blocking the region to be treated from the surroundings, such as the immobilization / stabilization method, cannot be applied.

In other words, the treatment of the contaminated soil directly under the building, in the premises of the facility under operation, or in the surrounding area is carried out without moving the contaminated soil from the subterranean region in which it is present. There is a request to perform a purification process in the “in-situ” (hereinafter, referred to as “in-situ process”). However, the techniques that enable such in-situ treatment have only bioremediation and immobilization / stabilization methods in the past, and these methods have the problems as described above. That is, no technique has been conventionally provided that enables in-situ processing without the above-mentioned various problems.

The present invention has been proposed in view of the various problems of the prior art as described above, and it is possible to safely and effectively purify contaminated soil without adversely affecting the environment and others. Moreover, it is an object of the present invention to provide a soil purification method and apparatus capable of in-situ purification treatment.

[0009]

As a result of various researches, the inventors have found that hydrogen peroxide (H ₂ O ₂ ) is used as a ferrous ion (F 2
We paid attention to the fact that if the hydroxyl radical (OH.) generated when it is catalytically decomposed by e ²⁺ ) and the pollutant chemically react, it becomes a harmless substance. At the same time, since iron is present in the soil, if hydrogen peroxide is sprayed or injected into the soil to be purified, hydroxyl radicals and pollutants will chemically react, and there is a shortage of iron in the soil to be treated. In the case of spraying hydrogen peroxide and ferrous salt,
We paid attention to what should be injected.

The soil remediation method of the present invention is a soil remediation method for purifying underground soil containing pollutants, in which a drilling hole is drilled from the ground surface to a contaminated region where soil containing pollutants is present. And a step of injecting a purifying agent that decomposes pollutants into the soil containing the pollutants through an injection monitor located inside the drill hole,
Changing the depth of the injection monitor while rotating the injection monitor.

Here, the cleaning agent is preferably hydrogen peroxide. In this case, it is preferable to perform the step of injecting the pH adjusting agent in addition to the step of injecting the cleaning agent. Similarly, it is preferred to inject ferrous salts with hydrogen peroxide. In practicing the present invention, it is preferable that the contaminated region is drilled to the lowermost portion in the drilling step, and the monitor is stepped up in the step of changing the depth of the monitor. However, it is also possible to step down from above the contaminated area to below.

Examples of the pH adjuster here include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and sulfamic acid,
Organic acids such as citric acid, tartaric acid, malic acid, oxalic acid, acetic acid, formic acid, maleic acid, sodium hydrogen sulfate, potassium hydrogen sulfate, sodium dihydrogen phosphate, potassium dihydrogen phosphate,
Acidic sodium pyrophosphate, acidic potassium pyrophosphate,
It is preferable to add an acidic salt such as sodium acid metaphosphate or potassium acid metaphosphate. From the viewpoint of residual substances, sodium hydrogensulfate and potassium hydrogensulfate are particularly desirable as pH adjusters. The injection amount or injection amount of the pH adjusting agent is such that the soil after injection or injection has a pH of 2 to 5
It is preferable that the amount is such that an acidic atmosphere is obtained.
Further, the pH adjusting agent may be injected prior to injecting a purifying agent such as hydrogen peroxide into the soil, or may be injected into the soil after injecting the purifying agent.

Further, it is preferable to inject the solidifying agent after injecting the cleaning agent.

Further, the soil purifying apparatus of the present invention is a soil purifying apparatus for purifying underground soil containing pollutants, by boring a drill hole from the ground surface to a contaminated region where soil containing pollutants is present. Excavating means, an injection monitor located inside the drill hole for injecting a purifying agent for decomposing the pollutant into the soil containing the pollutant, and the depth of the injection monitor while rotating the implant monitor. And an injecting monitor moving means for changing.

Here, the injection monitor preferably injects hydrogen peroxide as a cleaning agent, but it is preferable to inject not only hydrogen peroxide but also a ferrous salt. And
When hydrogen peroxide is used as the cleaning agent, it is preferable to inject the pH adjusting agent from the injection monitor before injecting the hydrogen peroxide and the ferrous salt. Further, the injection monitor preferably injects the solidifying agent after injecting the cleaning agent.

In carrying out the present invention, when the area where contaminated soil exists is large, it is preferable to repeat the above-mentioned method a plurality of times using the above-mentioned apparatus.

Further, when hydrogen peroxide is used as the cleaning agent, among the constituent elements of the soil cleaning apparatus of the present invention, the member that comes into contact with the cleaning agent is made of a material having an oxidant resistance. preferable.

Further, when hydrogen peroxide is used as a cleaning agent, it is preferable to add a stabilizer for hydrogen peroxide. Here, examples of stabilizers for hydrogen peroxide include phosphoric acid and salts thereof, ethylenediaminetetraacetic acid salt, DTPA, gluconic acid, oxine, 0-phenanthroline, thiourea, chelating agents such as organic phosphonic acids, methyl alcohol, ethyl alcohol, Alcohols such as n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and isobutyl alcohol, glycols such as ethylene glycol, propylene glycol and trimethylene glycol, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalene sulfone. Acids, sulfonic acids such as dodecylbenzene sulfonic acid, aminobenzene sulfonic acid, dimethylbenzene sulfonic acid and the like can be mentioned.
This stabilizer may be added before the hydrogen peroxide is injected into the soil or after the hydrogen peroxide is injected. The addition amount is not particularly limited, but is preferably 0.01% to 1.0% as a solution.

In carrying out the present invention, pollutants include petroleum hydrocarbons (TPH) and pentachlorophenol (PC).
P), perchlorethylene (PCE), polycyclic aromatic hydrocarbons (PAH), mercaptans, hexadecane,
Trifluralin (herbicide), dieldrin (insecticide),
Dynasab (herbicide), octachlorodibenzoparadioxin (OCDD), organic chlorine solvent (TCE, etc.),
Otherwise, hydrogen peroxide can be used as a cleaning agent.

In addition to the above, in the present invention, hydrogen chloride (H
When Cl) is generated, it is preferable to add sodium hydroxide for neutralization.

[0021]

According to the present invention having the above-mentioned structure,
A decontaminating agent, such as hydrogen peroxide (H ₂ O ₂ ), is sprayed onto the (contaminated) soil containing pollutants. This hydrogen peroxide reacts with iron in the soil (Fe ²⁺ : ferrous ion injected together with hydrogen peroxide when iron in the area to be treated is insufficient), according to the following formula, It produces hydroxyl radicals (OH.). H ₂ O ₂ + Fe ²⁺ → OH. + OH ⁻ + Fe ³⁺ Then, this hydroxyl radical (OH.) Causes a chemical reaction with various pollutants to become a harmless substance.

For example, octane (C ₈ H ₁₈ ) which is one type of petroleum hydrocarbon (TPH) and hydroxyl radical (OH.) React as shown in the following formula. The decomposition process of C ₈ H ₁₈ + 50OH · → 8CO ₂ + 34H ₂ O will be described in more detail. C ₈ H ₁₈ + OH · → C ₈ H ₁₇ + H ₂ O C ₈ H ₁₇ + OH · → C ₈ H ₁₇ OH C ₈ H ₁₇ OH + 2OH · → C ₇ H ₁₅ CHO + 2H ₂ O C ₇ H ₁₅ CHO + 2OH · → C ₇ H ₁₅ COOH + H ₂ O C ₇ H ₁₅ COOH + 44OH · → 8CO ₂ + 30H ₂ O, octane becomes carbon dioxide and water. It decomposes.

[0023]. Before hydroxyl radical (OH ·) decomposes the naphthalene is a polycyclic aromatic performed by a chemical reaction represented by _{C 10 H 8 + 48OH · →} 10CO 2 + 28H 2 O becomes Formula.

The decomposition of trichlorethylene (TCE) is
Chemical formula C ₂ HCl ₃ + 6OH · → 2CO ₂ + 3HCl + 2H ₂
Done by O 2.

The process of decomposing pesticide dieldrin by hydroxyl radical (OH.) Is represented by the chemical formula C ₁₄ H ₈ OCl ₆ + 56OH. → 14CO ₂ + 6HCl.
Expressed as + 29H ₂ O.

Propyl mercaptan which is a mercaptan is decomposed by CH ₃ (CH ₂ ) ₂ SH + 6OH. → CH ₃ (CH ₂ )
_The chemical formula is ₂ SO ₃ H + 3H ₂ O.

The chemical reaction for decomposing octachlorodibenzoparadioxin, which is a type of dioxin, with hydroxyl radicals is C ₁₂ O ₂ Cl ₈ + 36OH · → 12CO ₂ + 8HCl +
The chemical formula is 14H ₂ O.

As described above, according to the present invention, various pollutants are decomposed, so that various inconveniences caused by their existence are prevented. Then, it is possible to perform a purification process on a plurality of types of pollutants.

According to the present invention, the injecting monitor is injected while injecting the purifying agent through the injecting monitor housed in the drill hole drilled up to the contaminated region in the soil containing the pollutant. Since it is rotated and pulled up to the top of the polluted area, the pollutant in the soil is processed on the spot (in-situ processing) without moving from the area where it exists.
Since this in-situ processing is possible, even if soil contamination occurs in various operating facilities as described above, it does not affect the operation of the facility (using a small construction machine). It can be rapidly purified. That is, because the place polluted by harmful substances or pollutants is directly under the building, or on the premises of operating equipment or in the surrounding area, excavation such as incineration method, soil cleaning method, bioremediation, etc. Even if the treatment method involving the step of removing the soil cannot be carried out, the present invention by the in-situ treatment can be carried out. Further, unlike the immobilization / stabilization method, it is not necessary to shield the region to be treated from the surroundings, so that the present invention can be implemented even if the immobilization / stabilization method cannot be performed. In other words, the request for "soil purification by in-situ treatment", which was impossible to meet with the conventional technology,
The present invention can be implemented for the first time.

More specifically, according to the present invention capable of in-situ treatment, it is not necessary to take the contaminated soil to the ground and treat it. Therefore, evaporation of volatile pollutants into the atmosphere due to excavation of contaminated soil, scattering of pollutants due to transportation of contaminated soil, and secondary pollution due to other reasons are prevented.

Further, according to the present invention, since the harmful substances are decomposed by the above-mentioned chemical reaction, there is no inconvenience that further harmful compounds are generated as in the case of carrying out the incineration method. In addition, since harmful substances are decomposed, safety is permanent once the treatment is performed. Therefore, it is not necessary to monitor the outflow or leakage of pollutants with time after the treatment as in the immobilization / stabilization method. In the present invention, it is not necessary to excavate and remove the contaminated soil, and since the substance generated by the chemical reaction is harmless, it is not necessary to perform wastewater treatment after washing as in the soil washing method. And by devising the mode of the injection or injection work of the purifying agent,
A large amount of contaminated soil can be treated. Moreover, since the substance generated by the chemical reaction is also harmless, the problem of the change of the ecosystem does not occur unlike the case of bioremediation. Further, since harmful substances are decomposed by a chemical reaction, the repair period is much shorter than in the case of decomposition by organisms or microorganisms. Also, as mentioned above,
The present invention, which makes a harmless substance by chemically reacting with various pollutants, can treat other than volatile pollutants, unlike the soil air extraction method. Moreover, since the pollutants are not separated but decomposed by a chemical reaction, there is no concern about secondary pollution.

Here, the hydroxyl radical (OH.)
The chemical reaction for decomposing various pollutants by using is effective when carried out in an acidic atmosphere (a range of pH 2 to pH 5 is particularly preferable). In the present invention, if a pH adjusting agent is injected prior to the step of injecting the purifying agent to make the soil to be treated in an acidic atmosphere (particularly preferably in the range of pH 2 to pH 5), such a request can be met. It is possible. In particular,
Sodium bisulfate and potassium bisulfate are preferable because they have a buffer in an acidic region and do not leave a problematic substance in soil, groundwater, etc.

When hydrogen peroxide is added to the soil, not only hydroxyl radicals are generated by the reaction of H ₂ O ₂ + Fe ²⁺ → OH. + OH ⁻ + Fe ³⁺ , but H ₂ O is added in the presence of Fe ^3+. _An ineffective decomposition reaction of ₂ O ₂ → 1 / 2O ₂ + H ₂ O occurs. In the present invention, when hydrogen peroxide is used as a purifying agent, it is convenient to add a stabilizer of hydrogen peroxide because the above-mentioned ineffective decomposition reaction can be suppressed.

In the present invention, hydrogen chloride (HCl) may be generated when the pollutant is decomposed by the chemical reaction by the purifying agent. In such a case, if sodium hydroxide is added in the present invention, hydrogen chloride is neutralized to become sodium chloride and water. None of these substances are harmless.

In addition to this, the purifying agent or the like is injected or injected into the ground in the present invention as described above, but since a large amount of liquid is injected into the soil, there is a problem that the geology is disturbed. . On the other hand, in the present invention, if the purifying agent and the pH adjusting agent are injected, and the solidifying agent is injected after the injection,
It is convenient because the solidification action of the solidifying agent prevents the disturbance of the geology.

[0036]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1-3 are explanatory views of the first embodiment of the present invention. FIG. 1 shows the ground or soil on which the first embodiment is to be implemented. In FIG. 1, the symbol G indicates the soil to be purified, and the hatched area CA in the soil G is the contaminated area. In addition, the code | symbol WL has shown the water level of groundwater, and the code | symbol S has shown the ground surface.

In soil purification, first, as shown in FIG.
A drilling hole H is drilled in the soil G to be treated, and the tip of the drilling hole H (the portion where the drilling monitor M is located) is made to reach the lowermost part of the contaminated area CA. In FIG. 2, reference symbol A is a device for performing a cleaning process such as drilling work, and reference symbol R is a rod used for drilling a drill hole H.

As shown in FIG. 3, a jet M of hydrogen peroxide is jetted from the monitor M as a purifying agent. Here, when the content of iron in the ground is small, the ferrous iron salt is also jetted by the jet J. This hydrogen peroxide reacts with iron in soil (a ferrous salt sprayed with hydrogen peroxide when iron in the region to be treated is insufficient), and as described above, hydroxyl radicals (OH .) Is generated, and this hydroxyl radical (OH.) Causes a chemical reaction with various pollutants to become a harmless substance. In FIG. 3, the jet J is sprayed or injected into the soil at the bottom of the contaminated area CA. If the rod R is pulled up in this state, hydrogen peroxide and ferrous salt are injected into the entire contaminated area CA. The pollutants are decomposed or purified by hydroxyl radicals.

Here, when injecting the purifying agent, the rod for excavation is pulled up and the rod for injecting is inserted into the excavating hole H after completion of the boring operation, or the monitor M has the excavating function and the purifying agent ejecting function. It is configured to have both. As an example having both the excavation function and the purifying agent injection function, for example, as shown in a monitor M1 in FIG. 4, a high-pressure water flow path R1 for excavation and hydrogen peroxide (hydrogen peroxide and An annular flow path R2 for ferrous salt) is provided, and when the drilling of the excavation hole H is completed, the ball (flow path conversion ball valve) B is dropped through the flow path R1 and A type that closes the nozzle NH from which the high-pressure water jet HJ for jetting can be used. 4 shows the nozzle N
It shows the moment when H is closed, and expresses the moment when the high-pressure water jet HJ for excavation cannot be ejected.

FIG. 5 shows an apparatus A for carrying out the purification treatment shown in FIGS. The apparatus A is roughly configured by a hydrogen peroxide supply system 10 and a ferrous salt supply system 12. The hydrogen peroxide supply system 10 mixes hydrogen peroxide with the hydrogen peroxide tank 14, the hydrogen peroxide pump 32, the flow meter 34, and the water pumped from the water tank 16 via the pump 17. Mixer 40, ferrous iron supply system 1
It has a proportional blending type infusion pump 20 and a flow meter 44 which are also used in FIG. On the other hand, the ferrous salt supply system 12 includes a ferrous salt tank 22, a ferrous salt pump 36, a flow meter 38, and water and hydrogen peroxide that are pumped from the water tank 16 via the pump 17. It has a mixing mixer 42 for mixing, a hydrogen peroxide supply system 10 and a proportional mixing injection pump 20, and a flow meter 46. Then, the hydrogen peroxide supply system and the ferrous salt supply system meet at the swivel joint 28 of the rod R, and pass through the flow path (not shown in FIG. 5) in the rod R and the monitor M to form soil as a jet J. Is injected into.

Here, the storage tanks 14, 16, 22
Is preferably made of dilite (polyethylene).
Further, although only the swivel joint 28 is shown in FIG. 5, various hose joints which are present in the apparatus A in large numbers are
A hard stainless steel is used in consideration of resistance to hydrogen peroxide and damage resistance to a liquid containing a ferrous salt. Further, the injection pump, particularly the pump 20 provided in the hydrogen peroxide supply system 10, is made of a special material having an oxidant resistance (hydrogen peroxide resistance) (hereinafter referred to as “oxidant resistance special material”).
That is). Similarly, it is preferable that the portion from the swivel joint 28 to the portion where the hydrogen peroxide flows to the rod R and the monitor M are made of an oxidation resistant special material and stainless steel. Here, the antioxidant-resistant special material has a composition as shown in FIG. The packings are made of polyethylene or vinyl chloride-based material, ideally Teflon, and the hoses are made of polyethylene or vinyl chloride-based material.

Next, referring to FIG. 7, the construction procedure of the embodiment shown in FIGS. 1-3 will be described in more detail. First,
Regarding the soil for which purification treatment is planned, the area of the contaminated area, the depth of the contaminated area, the direction and flow velocity of the groundwater flow, etc. are identified, the pollutants are identified, and the amount of the identified pollutants is identified. The pH of the soil and water in the layer and water level is confirmed, and other so-called preliminary investigation is performed (step S1). And
It is determined whether or not each numerical value obtained in the preliminary investigation in step S1 conforms to the environmental standard (step S2).
If each numerical value obtained in the preliminary survey conforms to the environmental standard (YES in step S2), the soil is not contaminated, or even if it is contaminated, there is no problem in the environmental standard, and the treatment is performed. End (END). If it does not meet the environmental standard (NO in step S2), it is determined that the purification process is necessary, and it is examined whether or not the construction method of the present invention is applicable (step S3).

When the construction method of the present invention is inconvenient for the soil purification treatment (NO in step S3), the construction method described in this specification is abandoned and the adoption of another technique is examined (step S4). On the other hand, if the construction method of the present invention is applicable (YES in step S3), specific conditions necessary for the construction of the present invention, such as pH treatment amount of soil, required amount of hydrogen peroxide, first The necessary amount of iron salt, the necessity of repetition (repeating method will be described later), and others are examined (step S5).

After examining various concrete conditions, the construction cost of the present invention is roughly estimated, and whether or not the cost is appropriate, in other words, reasonable compared with the cost when other techniques are adopted. Whether or not (step S
6). When the cost performance in the case of adopting the construction method of the present invention is inferior to the cost performance in the case of adopting another technique, (step S6
No), consider using another construction method (step S).
4).

If there is no problem in terms of cost (step S
6 is YES), the necessity of pH adjustment is examined (step S7). If pH adjustment is required (YES in step S7)
S) Perform construction with pH adjustment (step S8) according to another embodiment described later, and if not necessary (step S
7 is NO) Construction is carried out according to the embodiment of FIGS. 1-3 or another embodiment (step S9).

After each processing (step S8 or step S9) is completed, it is examined whether or not the construction result is desired (step S10). If the desired result is not obtained (NO in step S10),
If the desired result is obtained by repeating the process of step S3 and subsequent steps (YES in step S10), the necessity of injecting the solidifying agent is considered (step S11). If it is not necessary to inject the solidifying agent (NO in step S11), the cleaning process is ended, and if the solidifying agent is required to be injected (Y in step S11).
(ES) A solidifying agent is injected in a manner described later (step S12), and the purification process is completed.

Note that FIGS. 8, 9 and 10 show an example of the case where the perforation shown in FIG. The concrete core boring machine A1 (FIG. 8) has a core tube 54 having a diamond bit 52 mounted on the tip thereof. Note that reference numeral 5
Reference numeral 6 indicates a crushed stone under the floor board 50. After the circular through hole 60 (FIG. 9) is formed in the flooring floor lining 50 by the concrete core boring machine A1, the drill hole is drilled by the boring machine A2 (FIG. 9). The drilling operation is shown in FIG. Note that the symbol SM in FIG.
Indicates a drilled slime.

FIG. 11 shows the step-up of the monitor M during the injection of the cleaning agent (hydrogen peroxide). Note that the order of steps 1, 2, and 3 shown in FIG.
A so-called “step down” in which step 3, step 2 and step 1 descend is also possible.

Although not clearly shown in the embodiment of FIGS. 1-11, when the purification by hydrogen peroxide injection has progressed to a certain degree, a coagulant is injected and a large amount of the purification agent or the like is added to the soil. It is also possible to compensate for the fact that the geology is disturbed due to the injection (FIG. 7: loop of YES in step S11 and step S12).

FIG. 12 shows a second embodiment of the present invention. In this embodiment, in addition to drilling the drill hole H,
A plurality of pumping wells W1 ... and purified water condensing wells W2 ... Are drilled. This is because the pumping well W1 and the purified water condensing well W2 are used together with the injection of hydrogen peroxide as a purifying agent, thereby providing a hydraulic gradient to increase the flow rate of groundwater and measure the improvement of the purification rate. It is a thing. Other functions are similar to those of the above-described embodiment. It should be noted that also in this embodiment, it is possible to inject the solidifying agent after the purification has progressed to a certain degree.

FIGS. 13, 14 and 15 show a third embodiment of the present invention. The third embodiment is step S in FIG.
7 corresponds to a YES loop and step S8, and is different from the first and second embodiments in that it has a step of injecting or injecting a pH adjusting agent. Note that FIG.
15 and FIG. 15, a plurality of steps are shown and described in the same drawing for simplification of description.

FIG. 13 shows a pH adjusting agent injecting operation which is an operation (advancing operation) in advance in the third embodiment. First, in FIG. 13, in the piercing work indicated by reference numeral (1), the drilling rod R is used to drill the drilling water DW to the lowermost part of the contaminated area CA.

Next, a pH adjusting agent (indicated by jet J11 in the figure) is injected or injected from the monitor M (FIG. 14) at the tip of the rod R by the injection process indicated by reference numeral (2). Then, when a predetermined amount of the pH adjusting agent is injected, as shown in FIG. 14, the step is increased by about 250 mm to 500 mm, and the pH adjusting agent is injected at another depth level of the contaminated area CA. However, not only step up,
The implantation level may be changed by so-called step-down. Also, the number of steps changes depending on the range of the contaminated area. Here, as described above, the pH adjusting agent is effective when the chemical reaction of decomposing various pollutants using hydroxyl radicals (OH.) Is performed in an acidic atmosphere (a range of pH 2 to pH 5 is particularly preferable). Due to the above, the pH adjusting agent is injected prior to the step of injecting the purifying agent, and the soil to be treated is treated in an acidic atmosphere (particularly preferably pH2-pH5).
Range)) to respond to requests to keep.

When the injection process is completed, the drawing process indicated by reference numeral (3) in FIG. 13 is performed. Reference numeral H is a drilled hole.

Next, the following construction (subsequent construction) shown in FIG. 15 will be described. This construction is basically the same as in the first embodiment. However, as apparent from the drawing process indicated by reference numeral (3) in FIG. 13, since the excavation hole H has already been drilled (see the step indicated by reference numeral (1) in FIG. 15), the drilling step is necessary. do not do.

In the first step of the injection process indicated by reference numeral (2), the rod R having the injection monitor M mounted therein is inserted into the excavation hole H, and purification is performed at the lowermost part of the contaminated area CA into which the pH adjusting agent has been injected. Hydrogen peroxide as an agent (Jet J in Fig. 15)
Injected or injected). When the iron content in the soil is insufficient, ferrous salt is also injected. When a predetermined amount of hydrogen peroxide has been injected, the process is stepped up, and the second injection step shown by reference numeral (3) is performed. The number of steps changes depending on the range of the contaminated region, as in the case of the pH adjuster injection process.

When the injection of hydrogen peroxide is completed, the drawing work indicated by reference numerals (4) and (5) is performed, and the construction is completed. If necessary, the solidifying agent can be injected according to the progress of injection of the cleaning agent.

FIG. 16 shows a fourth embodiment of the present invention. The fourth embodiment is similar to the above-mentioned third embodiment in that it has a step of injecting a pH adjuster. However, in the third embodiment, the pH adjuster injection process and the hydrogen peroxide (purifying agent) injection process are performed using separate rods and monitors, whereas in the fourth embodiment, the same rod is used. It is different in that it is done by.

In the construction of the fourth embodiment, in the drilling step shown by the reference numeral (1) in FIG. 16, a drilling hole H reaching the lowermost part of the contaminated area (see the drawing work of the reference numeral (5)) is drilled, and the reference numeral (2) is given. ) Jet J11 by the pH adjuster injection process
The pH adjusting agent indicated by is injected or injected, and hydrogen peroxide (jet J) is injected at the hydrogen peroxide (purifying agent) injecting step indicated by reference numeral (3) to decompose the contaminants. here,
Since the pH of the contaminated area CA is adjusted in an acidic atmosphere (particularly preferably in the range of pH2 to pH5) by injecting a pH adjuster, it depends on hydroxyl radicals (OH.) Generated as a result of hydrogen peroxide injection. The decomposition reaction of the pollutants preferably proceeds.

Then, step up is performed a number of times corresponding to the contaminated region (step shown by reference numeral (4)), and when injection of the pH adjusting agent and the purifying agent is completed, the rod R is pulled up (shown by reference numeral (5)). Pulling work).

In the fourth embodiment shown in FIG. 16, there was a time lag between the injection of the pH adjuster and the injection of hydrogen peroxide (purifying agent), but the fifth embodiment of the present invention shown in FIG. Then, the injection of the pH adjusting agent and the injection of hydrogen peroxide are simultaneously performed. In the fifth embodiment of FIG. 17, in the drilling work indicated by reference numeral (1), the monitor M at the tip of the rod R jets high-pressure water HJ for drilling to drill a drilling hole in the ground G. Here, excavation may be performed by spraying a pH adjuster instead of the high-pressure water HJ.

Then, the implantation process shown by the reference numeral (2) is performed at the lowermost part of the contaminated area CA. In this case, FIG.
8, the pH adjusting agent (jet J11) is injected or injected from the upper nozzle NP, and hydrogen peroxide (jet J) is injected or injected from the lower nozzle NL. That is, the pH adjuster and hydrogen peroxide are simultaneously injected. This implanter is stepped up or down as necessary.

After the injection process is completed, reference numeral (3) in FIG.
Perform the drawing work shown in. In the pouring process, a solidifying agent for stabilizing the ground may be injected if necessary. Here, FIG. 19 shows the cross-sectional shape of the rod R used in the fifth embodiment. The rod R has a concentric circular shape, and the central circular conduit R3 is a supply conduit for hydrogen peroxide and high-pressure water for excavation, and is switchable. The annular pipe line R4 on the outer side is a supply line for the ferrous salt, and the annular pipe line R5 on the outer side is a supply line for the pH adjusting agent.

In the above-mentioned fifth embodiment, hydrogen peroxide and pH are used.
The adjusting agent is pumped by a separate route until it is injected, but it is possible to mix the hydrogen peroxide and the pH adjusting agent before reaching the rod R. The construction plant shown in FIG. 20 is used in such a sixth embodiment of the present invention. The apparatus of FIG. 20 is similar to the apparatus shown in FIG. 5, but differs in having a pH adjusting agent supply system. In FIG. 20, reference numeral 70 indicates a tank for pH adjusting agent. The pH adjusting agent is a mixing tank (or mixer) 4
At 0A, it is mixed with water from the water tank 16 and hydrogen peroxide from the hydrogen peroxide tank 14. The supply system 12 of the ferrous salt and the supply system 10A of the mixture of hydrogen peroxide and the pH adjusting agent are respectively pumps 20 for pressure feeding.
A and 20B are interposed. Other configurations and operations are
Since it is the same as the case of the above-mentioned third to fifth embodiments, duplicated explanation is omitted.

Although not clearly shown in the drawings, in the above-mentioned various embodiments, if the one-time cleaning process is not sufficient because the contaminated area CA covers a wide range, perforation, injection, step It is sufficient to repeat up (or step down) and pull out. Step S5 of FIG.
The wording "repetition specification" in this means this.

[0067]

The effects of the present invention are listed below.

(1) In-situ treatment of pollutants in soil is possible. (2) Even if soil pollution occurs in various operating facilities as described above, it can be rapidly purified without affecting the operation of the facilities. (3) It is not necessary to take out the contaminated soil to the ground and treat it. Excavation of the contaminated soil evaporates volatile pollutants into the atmosphere, transport of the contaminated soil disperses pollutants, and other secondary causes. Contamination is prevented. (4) No more harmful compounds are generated during the treatment. (5) Since the security will last once processed,
There is no need to monitor spills or leaks of pollutants over time. (6) There is no need to perform wastewater treatment after cleaning. (7) A large amount of various pollutants can be treated. (8) The problem of ecosystem change is prevented. (9) The repair period is short.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state of contaminated soil before the construction of the present invention.

FIG. 2 is a diagram showing a perforation step in the first embodiment of the present invention.

FIG. 3 is a diagram showing an injection or injection process in the first embodiment.

FIG. 4 is a vertical sectional view showing an example of a nozzle used in the first embodiment.

FIG. 5 is a block diagram showing a purification processing apparatus used in the first embodiment.

FIG. 6 is a table showing the composition of an oxidizing agent-resistant special material that is a part of the apparatus of FIG.

FIG. 7 is a flowchart showing a construction procedure of the present invention.

FIG. 8 is a diagram showing details of an example of a punching step shown in FIG.

FIG. 9 is a diagram showing a punching process in a step different from that of FIG. 8;

FIG. 10 is a diagram showing a punching step in a stage different from those in FIGS. 8 and 9;

FIG. 11 is a diagram showing step-up / step-down of the injection step in the first embodiment.

FIG. 12 is a diagram showing a second embodiment of the present invention.

FIG. 13 is a diagram showing a preceding process in the third embodiment of the present invention.

FIG. 14 is a diagram showing step-up / step-down of the preceding process of FIG.

FIG. 15 is a view showing the trailing process of the third embodiment.

FIG. 16 is a diagram showing a fourth embodiment of the present invention.

FIG. 17 is a diagram showing a fifth embodiment of the present invention.

FIG. 18 is a diagram schematically showing a monitor used in the fifth embodiment.

FIG. 19 is a cross sectional view schematically showing a rod used in the fifth embodiment.

FIG. 20 is a block diagram showing a purification processing device used in a sixth embodiment of the present invention.

[Explanation of symbols]

G ... Soil CA ... Contaminated area WL ... Groundwater level S ... Ground surface H ... Drilling hole M, M1 ... Monitor A ... Purification treatment device R ... Rod J. .. Jet of purifying agent (hydrogen peroxide) R1 ... High-pressure water flow path for excavation R2 ... Annular flow path for hydrogen peroxide (hydrogen peroxide and ferrous salt if necessary) B. ..Ball (ball valve for flow path conversion) HJ ... High-pressure water jet for excavation NH, NP, NL ... Nozzle 10 ... Hydrogen peroxide supply system 12 ... Ferrous salt supply system 14. ..Hydrogen peroxide tank 32 ... Hydrogen peroxide pump 34, 38, 44, 46 ... Flow meter 16 ... Water tank 17, 20, 20A, 20B, 32, 36 ... Pump 40 , 40A, 42 ... Mixing mixer (mixing tank) 22 ... Ferrous salt tank 28.・ Swivel joint 50 ・ ・ ・ Floor floor concrete A1 ・ ・ ・ Concrete core boring machine 52 ・ ・ ・ Diamond bit 54 ・ ・ ・ Core tube 56 ・ ・ ・ Crushed stone 60 ・ ・ ・ Circular through hole formed in floor floor concrete A2・ ・ ・ Boring machine SM ・ ・ ・ Drilling slime

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area B09B 3/00 ZAB

Claims (10)

[Claims] 1. A method of soil purification for purifying underground soil containing pollutants, the method comprising: drilling a drill hole from a ground surface to a polluted region where soil containing pollutants is present; and the drill hole. Spraying a purifying agent that decomposes pollutants into the soil containing the pollutant through an injecting monitor located inside, and changing the depth of the injecting monitor while rotating the injecting monitor. A soil purification method comprising: 2. The purifying agent is hydrogen peroxide.
Soil purification method. 3. The soil purification method according to claim 2, wherein the step of injecting a pH adjuster is performed. 4. The soil purification method according to claim 2, wherein the ferrous salt is injected together with hydrogen peroxide. 5. The soil purification method according to claim 1, wherein the solidifying agent is sprayed after the cleaning agent is sprayed. 6. A soil purifying apparatus for purifying underground soil containing pollutants, and a drilling means for drilling a drill hole from a ground surface to a polluted region where soil containing pollutants is present, and the drilling hole. An injection monitor for injecting a cleaning agent which decomposes the pollutant into the soil containing the pollutant inside the injection monitor, and an injection monitor moving means for changing the depth while rotating the injection monitor. A soil purification device comprising: 7. The soil purifying apparatus according to claim 5, wherein the injection monitor injects hydrogen peroxide as a purifying agent. 8. The soil purification apparatus according to claim 5, wherein the injection monitor injects hydrogen peroxide and ferrous salt. 9. The soil purifying apparatus according to claim 6, wherein the injection monitor injects a pH adjusting agent. 10. The soil purifying apparatus according to claim 6, wherein the injection monitor injects the solidifying agent after injecting the cleaning agent.