JP3192078B2 - Soil purification method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can purify an area contaminated with volatile contaminants having a relatively low boiling point, such as petroleum hydrocarbons in soil, without displacing its position. Method and apparatus.

[0002]

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

[0003] Such soil contamination directly causes plant growth inhibition and growth inhibition of organisms (including microorganisms) in the soil. In addition, when pollutants are dissolved in water (including groundwater), the water is polluted. When the pollutants are volatilized and diffused into the atmosphere, they cause air pollution and adversely affect the human body (health). . Furthermore, by being absorbed by crops, pollutants accumulate in the crops and livestock that have eaten the crops, thus contaminating the environment. In particular, contaminants that exist deep underground may gradually elute into groundwater and move over a wide area, and there is a possibility that the above-mentioned damage may occur over a wide area.

Conventionally, for such soil contamination, an incineration method in which contaminants are taken out together with the soil and incinerated in an incinerator or the like, a contaminated area is enclosed with a wall of concrete or the like, or contaminated, An immobilization / stabilization method for pouring solidified material into an area to solidify and stabilize the area, a soil washing method for excavating and removing contaminated soil and washing it with water, chemicals, etc. Or bioremediation that injects microorganisms directly into contaminated soil and decomposes contaminants in soil by microorganisms.
A well was dug at the site of contamination, and the soil was extracted by suction to remove volatile harmful organic substances.

[0005]

However, when the ground or soil is contaminated by harmful substances or pollutants,
It can be located on the premises of a cleaning factory, on the premises of a manufacturing plant for semiconductors, etc., on the premises of an energy plant using fossil fuels, directly under a building such as the premises of a petrochemical factory, or on an operating site such as a waste treatment plant. Most of the facilities are located on or around the premises. For this reason, it is impossible to employ a treatment method that involves a step of removing contaminated soil by excavation, such as an incineration method or a soil washing method. For similar reasons, immobilization /
As in the case of the stabilization method, a processing method that requires a step of blocking an area to be processed from the surroundings cannot be performed.

[0006] In other words, the treatment of contaminated soil immediately below a building, on the premises of operating equipment, and in the surrounding area, is a treatment that does not move the contaminated soil from the underground area where it exists, which is a so-called treatment. There is a request to perform a purification process in the “in-situ” (hereinafter, referred to as “in-situ process”).

[0007] Here, the only techniques that enable such in-situ treatment are bioremediation and immobilization / stabilization methods. However, in the case of the immobilization / stabilization method, it is necessary to monitor over time so that the contaminants do not leak or leak after the treatment. In addition, since the contaminants remain, the safety is not permanent. On the other hand, in the case of bioremediation, there is a problem that an ecosystem is changed in order to breed dominant organisms or microorganisms that selectively degrade pollutants,
There is a problem that the repair period is long.

[0008] In other words, a technique that enables in situ processing without having various problems as in the bioremediation and immobilization / stabilization methods has not been provided so far.

[0009] Still other conventional techniques include a method of injecting steam into soil and evaporating and removing contaminants by the heat, and a method of injecting quicklime into soil to mix with the soil and generate at that time. There is a method of vaporizing and removing contaminants by heat. However, these techniques cannot solve the above-mentioned problems of the related art.

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

[0011]

As a result of various studies, the inventors have found that, for example, hydrogen peroxide (H ₂ O ₂ ) is converted to ferrous ion (F
It was noted that a chemical reaction between a hydroxyl radical (OH.) generated when catalytically decomposed by e ²⁺ ) and a contaminant results in a harmless substance. At the same time, iron is present in the soil, so if hydrogen peroxide is injected or injected into the soil to be purified, hydroxyl radicals and contaminants react chemically, and the soil to be treated is short of iron In the case, spray hydrogen peroxide and ferrous salt,
We focused on what should be injected. At the same time, attention should be paid to the fact that if the reaction heat generated by such a reaction is used, volatile contaminants having a relatively low boiling point (eg, organic chlorine-based contaminants) can be vaporized to promote soil purification. did.

According to the present invention, in a soil purification method for purifying underground soil containing a pollutant, the area and depth of a polluted area and the amount of the pollutant are investigated for soil to be treated for purification. Drilling the injection hole and aeration well from the ground surface to the bottom of the contaminated area where the soil containing the contaminant exists, inserting the monitor into the injection hole, rotating the depth while changing the contaminant from the monitor Injecting a purifying agent containing hydrogen peroxide to decompose, vaporizing the pollutant by the purifying agent, discharging the vaporized pollutant from the aeration well, and adsorbing the discharged vaporized pollutant in the adsorption tower. At the same time, contaminants that cannot be adsorbed and removed are burned.

In practicing the present invention, it is preferable to perform a step of injecting a pH adjuster in addition to the step of injecting the purifying agent. Similarly, it is preferred to inject the ferrous salt with hydrogen peroxide. In practicing the present invention, it is preferable to excavate to the bottom of the contaminated area in the excavation step, and to step up the monitor in the step of changing the depth of the monitor. However, it may be stepped down from above the contaminated area.

Here, as the pH adjuster, for example, 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 phosphorus dihydrogen,
Sodium acid pyrophosphate, potassium acid pyrophosphate,
It is preferable to add an acid salt such as sodium acid metaphosphate and potassium metaphosphate. From the viewpoint of residual substances, sodium hydrogen sulfate and potassium hydrogen sulfate are particularly desirable as pH adjusters. The injection amount or injection amount of the pH adjuster is such that the soil after the injection or injection has pH 2 to pH 5
It is preferable that the amount is such that an acidic atmosphere is obtained.
Further, the pH adjuster may be injected before 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 consolidating agent after injecting the purifying agent.

[0016]

Further, according to the present invention, in a soil purification apparatus for purifying underground soil containing a pollutant, an injection hole and an aeration well extending from the ground surface to a contaminated area where the soil containing the pollutant is present are excavated. Digging means, an injection monitor for injecting a purifying agent that decomposes the pollutant into soil containing the contaminant located inside the injection hole, and a depth of the injection monitor while rotating the injection monitor. Injection monitor moving means for changing the, and suction means for discharging from the aeration well the contaminants vaporized by the purifying agent and discharged from the aeration well, and an adsorption tower for adsorbing the sucked contaminants, A high-temperature incinerator for incinerating contaminants not adsorbed and removed by the adsorption tower, a cooling tower for cooling the substance generated in the high-temperature incinerator, and a purifying agent injection device comprising a hydrogen peroxide supply system and a first And a supply system of the salt.

[0018]

Prior to injecting hydrogen peroxide and ferrous salt, it is preferable to inject a pH adjuster from the injection monitor. Further, it is preferable that the injection monitor injects the solidifying agent after injecting the purifying agent.

In practicing the present invention, if the area where contaminated soil is present is large, a plurality of injection holes and aeration wells are excavated, and the above-described method is repeated a plurality of times using the above-described apparatus. Is preferred.

When hydrogen peroxide is used as a purifying agent, members of the soil purifying apparatus of the present invention that come into contact with the purifying agent are made of an oxidant-resistant material. preferable.

Further, when using hydrogen peroxide as a purifying agent, it is preferable to add a stabilizer for hydrogen peroxide. Here, as a stabilizer of hydrogen peroxide, phosphoric acid and salts thereof, ethylenediamine tetraacetic 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, and naphthalene sulfone And sulfonic acids such as acid, dodecylbenzenesulfonic acid, aminobenzenesulfonic acid, and dimethylbenzenesulfonic acid.
The stabilizer may be added before the injection of hydrogen peroxide into the soil, or may be added after the injection of hydrogen peroxide. The amount of addition is not particularly limited, but is preferably about 0.01% to 1.0% as a solution.

In practicing the present invention, the pollutants are petroleum hydrocarbons (TPH), pentachlorophenol (PC
P), perchlorethylene (PCE), polycyclic aromatic hydrocarbons (PAH), mercaptans, hexadecane,
Trifluralin (herbicide), dieldrin (pesticide),
Dynasub (herbicide), octachlordibenzoparadioxin (OCDD), organic chlorinated solvents (TCE, etc.),
Otherwise, hydrogen peroxide can be used as a purifying agent.

In addition to the above, according to the present invention, as a result of decomposition of contaminants by a purifying agent by a chemical reaction, hydrogen chloride (H
When Cl) is generated, sodium hydroxide is preferably added for neutralization.

According to the present invention having the above-described structure, a purifying agent, for example, hydrogen peroxide (H ₂ O ₂ ) is sprayed on (contaminated) soil containing pollutants. This hydrogen peroxide reacts with iron in the soil (Fe ²⁺ : ferrous ions injected together with hydrogen peroxide when iron is not enough in the soil in the area to be treated) according to the following formula,
Generates hydroxyl radical (OH.). H ₂ O ₂ + Fe ²⁺ → OH. + OH ⁻ + Fe ³⁺ The hydroxyl radical (OH.) Causes a chemical reaction with various contaminants to form a harmless substance.

For example, octane (C8 H18), a kind of petroleum hydrocarbon (TPH), reacts with a hydroxyl radical (OH.) As follows. C ₈ H ₁₈ + If _{50OH · → 8CO 2 + 34H 2} O decomposition process in more detail be described by the following chemical formula _{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 + 2 OH → C ₇ H ₁₅ CHO + 2H ₂ O C ₇ H ₁₅ CHO + ₂ OH → C ₇ H ₁₅ COOH + H ₂ O C ₇ H ₁₅ COOH + 44 OH →→ 8 CO ₂ +30 H ₂ O According to the formula, octane is converted into carbon dioxide and water. It breaks down.

When the hydroxyl radical (OH.) Decomposes the polycyclic aromatic naphthalene, a chemical reaction represented by the chemical formula of C ₁₀ H ₈ +48 OH → 10CO ₂ + 28H ₂ O is carried out.

The decomposition of trichloroethylene (TCE)
Chemical formula C ₂ HCl ₃ + 6OH. → 2CO ₂ + 3HCl + 2H ₂
O 2.

The process of degrading dieldrin, which is an agricultural chemical, by hydroxyl radical (OH.) Is performed by the chemical formula C ₁₄ H ₈ OCl ₆ + 56OH.fwdarw.14CO ₂ + 6HCl.
It is expressed by + 29H ₂ O.

The decomposition of propyl mercaptan, which is a mercaptan, is carried out by CH ₃ (CH ₂ ) ₂ SH + 6OHＯＨ → CH ₃ (CH ₂ )
_{It is represented by the} chemical formula ₂ SO ₃ H + 3H ₂ O.

The chemical reaction when decomposing octachlorodibenzoparadioxin, which is a kind of dioxin, by hydroxyl radical is C ₁₂ O ₂ Cl ₈ + 36OH. → 12CO ₂ + 8HCl +
It is represented by a chemical formula of 14H ₂ O.

The decomposition reaction of tetrachloroethylene (PCE) is performed as follows: CCl ₂ CCl ₂ + OH. → Cl ₂ CHCOCl + Cl
・ Cl ₂ CHCOCl + H ₂ O → Cl ₂ CHCOOH + H
Cl Cl ₂ CHCOOH + 2OH. → 2HCl + CO ₂ + H
COOH HCOOH + 2.OH → 2H ₂ O + CO ₂

As described above, according to the present invention, various contaminants are decomposed, so that various inconveniences caused by their presence are prevented. Then, purification treatment can be performed on a plurality of types of pollutants.

Here, the heat of decomposition of hydrogen peroxide (H ₂ O ₂ ) is expressed as H ₂ O ₂ → H ₂ O + (１ ／) O ₂ +23.45 Kcal (1 mol) in the ground. 23.45 / mol
Kcal. In the present invention, volatile contaminants having a low boiling point, such as mercaptans (methyl mercaptan) and trichloroethylene, are vaporized by utilizing such decomposition heat. Then, the soil is purified by extracting the vaporized pollutant through the aeration well, that is, removing the vaporized pollutant from the soil to be purified.

In this manner, the purification is performed by the decomposition of the contaminants by the chemical reaction between the purifying agent and the contaminants and the vaporization of the contaminants (the volatile contaminants having a relatively low boiling point and a relatively low boiling point) by the heat generated by the decomposition. The rate at which contaminants are removed from the soil of interest is dramatically increased. That is, the so-called “purification repair time” can be greatly reduced. In other words, according to the soil purification method and apparatus of the present invention, the contaminants are decomposed by the chemical reaction, and at the same time, the contaminants are vaporized by the generated reaction heat, thereby promoting the purification of the soil. .

Here, if the aeration well communicates with the adsorption means, the contaminants vaporized by the adsorbent provided in the adsorption means are removed, and the vaporized contaminants are prevented from diffusing into the atmosphere. It is possible to do. In addition, as shown in the above formula, hydrogen peroxide is decomposed in the ground to generate oxygen. Therefore, by introducing the vaporized pollutant and the oxygen into the incineration means and causing the combustion reaction to proceed, it is possible to prevent the harmful vaporized pollutant from diffusing into the atmosphere.

According to the present invention, the injection monitor is rotated while injecting the purifying agent through the injection monitor accommodated in the excavated injection hole up to the contaminated area in the soil containing the pollutant. And consequently, the contaminants in the soil are processed (in-situ processing) without moving from the area where they exist. Since this in-situ treatment is possible, even when soil contamination occurs in the various facilities in operation as described above, it does not affect the operation of the facilities (using a small construction machine). It can be purified quickly. In other words, since the place contaminated with harmful or contaminants is directly under the building, or on the premises of operating equipment or in the surrounding area, it can be contaminated by excavation, soil cleaning, bioremediation, etc. Even if a treatment method involving a step of removing soil is not feasible, the present invention by in-situ treatment can be carried out. Further, since there is no need to block the region to be treated from the surroundings as in the fixing / stabilizing method, the present invention can be implemented even if the fixing / stabilizing method cannot be performed. In other words, the request for "soil purification by in-situ treatment," which was impossible in the prior art,
The present invention has become possible for the first time.

More specifically, according to the present invention, which enables in-situ treatment, it is not necessary to take out contaminated soil to the ground and treat it. Therefore, secondary pollution due to evaporation of volatile pollutants into the atmosphere due to excavation of contaminated soil, scattering of pollutants due to transport of contaminated soil, and the like is prevented.

Further, according to the present invention, the harmful substances are decomposed by the chemical reaction as described above, and the vaporized harmful substances are also adsorbed or incinerated. Absent. In addition, because harmful substances are removed by decomposition or incineration, etc.
Once processed, security is permanent. for that reason,
There is no need to monitor the outflow or leakage of contaminants over time after treatment as in the immobilization / stabilization method. In the present invention, there is no need to excavate and remove contaminated soil, substances generated by chemical reactions are also harmless, and pollutants having a low boiling point are vaporized and discharged from the soil. There is no need for subsequent wastewater treatment. A large amount of contaminated soil can be treated by devising the mode of injection or injection of the purifying agent and the treatment form of the vaporized pollutant. The substances produced by the chemical reaction are harmless, and the vaporized pollutants are adsorbed by the adsorbent or incinerated by a large amount of oxygen. The problem does not arise. In addition, the harmful substances are decomposed by the chemical reaction and are vaporized by the heat of the chemical reaction and are discharged from the soil, so that the repair period is much shorter than that in the case of the decomposition by living organisms or microorganisms. Also, as mentioned above,
The present invention, which causes chemical reactions with various contaminants to be harmless and vaporizes volatile contaminants having a low boiling point and discharges them from the soil, does not separate the contaminants from the soil, but uses a chemical reaction. Since decomposition, adsorption, and incineration are performed, there is no need to worry about secondary contamination.

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

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

In the present invention, there is a case where hydrogen chloride (HCl) is generated when the contaminant is decomposed by the purifying agent through a chemical reaction. In such a case, if sodium hydroxide is added in the present invention, hydrogen chloride is neutralized into sodium chloride and water. All of these substances are harmless.

In addition to the above, in the present invention as described above, the purifying agent or the like is injected or injected into the ground. However, 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 consolidating agent is injected after the injection of the purifying agent or the pH adjusting agent, the injection,
This is convenient because geological disturbance is prevented by the solidifying action of the binder.

[0044]

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

FIG. 1-7 is a diagram for explaining the first embodiment of the present invention. In FIG. 1-3, reference numeral G denotes a soil to be purified, and a hatched area CA in the soil G is a contaminated area. Note that the symbol W
L indicates the level of groundwater, and S indicates the surface of the earth.

At the time of soil purification, an injection hole H and an aeration well E are excavated in the soil G to be treated. FIG. 2 shows a state in which the injection hole H and the aeration well E are excavated, and more specifically, shows a positional relationship on a plane with the contaminated area CA of the soil G. Tip of injection hole H (portion where drilling monitor M is located)
And the deepest part of the aeration well E is made to reach the lowest part of the contaminated area CA. Here, in FIG. 1, the injection hole H is shown in a state where the injection tube is inserted. Reference symbol A in FIG. 3 is an apparatus for performing excavation work and injection work,
Reference symbol R is a rod used for piercing the injection hole H.

As shown in FIG. 3, a jet J of hydrogen peroxide is injected from the monitor M as a purifying agent. Here, when the iron content in the ground is small, the ferrous salt is also jetted by the jet J. This hydrogen peroxide reacts with the iron content in the soil (in the case where the iron content is insufficient in the soil in the area to be treated, ferrous salt injected with the hydrogen peroxide), and as described above, the hydroxyl radical (OH .), And this hydroxyl radical (OH.) Causes a chemical reaction with various contaminants to make it a harmless substance. In FIG. 3, the jet J is injected or injected into the lowermost soil 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 decomposition or purification of contaminants by hydroxyl radicals is performed.

Here, when the purifying agent is injected, the drilling rod is pulled up after the drilling operation is completed, and the injection rod is inserted into the drilling hole H, or the monitor M performs the excavating function and the purifying agent injection function. It is configured to have both. As an example having both the excavating function and the purifying agent injection function, for example, as shown in a monitor indicated by reference numeral M1 in FIG. 4, a flow path R1 for high-pressure excavating water, a hydrogen peroxide (if necessary, hydrogen peroxide and An annular flow path R2 for ferrous salt is provided, and when the drilling of the excavation hole H is completed, a ball (flow path conversion ball valve) B is dropped via the flow path R1. A type that closes the nozzle NH from which the high-pressure water jet HJ for excavation jets can be used. FIG. 4 shows the nozzle N
H indicates the moment when it is closed, and expresses the moment when the high-pressure water jet HJ for excavation becomes impossible to jet.

When hydrogen peroxide and ferrous salt are injected into the entire contaminated area CA and the contaminants are decomposed or purified by hydroxyl radicals, the heat of chemical reaction causes volatile contaminants having a low boiling point. (For example, mercaptans and trichloroethylene) are vaporized. And FIG.
The vaporized pollutant indicated by the arrow V is discharged from the contaminated area CA or the ground G through the aeration well E (see the arrow VO in FIG. 1). As shown in FIG. 5, the vaporized contaminants are sent from the aeration well E to the adsorption tower 20 via the flow path L1. The adsorption tower 20 is filled with activated carbon and adsorbs vaporized pollutants. The contaminants that have not been adsorbed and removed in the adsorption tower 20 are sent to the high-temperature incinerator 22 via the flow path L2. Here, hydrogen peroxide decomposes at _{2H 2 O 2 → 2H 2 O} + O 2 becomes a chemical reaction to generate oxygen gas O _2. Then, since about 24 liters of oxygen gas is generated from 68 g of hydrogen peroxide, hydrogen peroxide is added to one cubic meter of soil.
When 0 kg is added, about 7 cubic meters of oxygen gas is generated. Such a large amount of oxygen gas is also discharged from the soil through the aeration well E together with the vaporized pollutants, and the high-temperature incinerator 2
2. As a result, in the high temperature incinerator 22,
The vaporized pollutant causes a combustion reaction with a large amount of oxygen.

The substance produced by the combustion reaction is sent to the cooling tower 24 via the line L3. And cooling tower 2
The analysis is performed before reaching 4, and when the products of the combustion reaction are harmless even if released to the atmosphere, they are released to the atmosphere via the line L4. On the other hand, as a result of analysis, if there are substances that cannot be released into the atmosphere,
The oxygen is supplied to the high-temperature incinerator 22 via the line L5 and supplied from the aeration well E, and the combustion reaction is performed again. During the combustion in the high-temperature combustion path 22, fuel is supplied from the auxiliary fuel supply means 26.

FIG. 6 shows an injection device indicated by reference numeral A in FIG. Note that FIG. 3 does not show the mechanism for treating the vaporized contaminants shown in FIG. Apparatus A shown in FIG. 6 is schematically composed of a hydrogen peroxide supply system 10 and a ferrous salt supply system 12. The hydrogen peroxide supply system 10 includes a hydrogen peroxide tank 14, a hydrogen peroxide pump 32, a flow meter 34, and a water tank 16.
A mixing mixer 40 for mixing the water and hydrogen peroxide pumped through 7, a proportional mixing injection pump 20 shared with the ferrous salt supply system 12, and a flow meter 44. 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 a water tank 16.
A mixing mixer 42 for mixing water and hydrogen peroxide pumped through 7, a proportional mixing injection pump 20 shared with the hydrogen peroxide supply system 10, and a flow meter 46 are provided. And
The hydrogen peroxide supply system and the ferrous salt supply system join at the swivel joint 28 of the rod R, and pass through the rod R and a flow path (not shown in FIG. 6) in the monitor M as a jet J into the soil. It is injected.

Here, storage tanks 14, 16, 22
Is preferably made of dielite (polyethylene).
Although only the swivel joint 28 is shown in FIG. 6, various hose joints existing in the apparatus A are:
Hard stainless steel is used in consideration of the resistance to hydrogen peroxide and the damage resistance to liquids containing ferrous salts. Further, the injection pump, particularly the pump 20 interposed in the hydrogen peroxide supply system 10, is made of a special material having oxidation resistance (hydrogen peroxide resistance) (hereinafter referred to as "oxidation resistance special material").
). Similarly, the portion from the swivel joint 28 to the rod R where the hydrogen peroxide flows and the monitor M are preferably made of an oxidant-resistant special material and stainless steel. Here, the oxidizing agent-resistant special material has a composition as shown in FIG. The packings are made of polyethylene or vinyl chloride material, ideally Teflon, and the hoses are made of polyethylene or vinyl chloride material.

Next, with reference to FIG. 8, the construction procedure of the embodiment shown in FIGS. 1-7 will be described in more detail. First,
For soil scheduled for purification treatment, grasp the area of the contaminated area, the depth of the contaminated area, the direction and velocity of the groundwater flow, identify the pollutants, identify the amount of the specified pollutants, The soil and water pH at the layer and the water level are confirmed, and other so-called preliminary investigations are performed (step S1). And
It is determined whether 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 (step S2: YES), the processing is determined as not contaminating the soil, or even if it is contaminated, there is no problem in the environmental standard. It ends (END). When it does not conform to the environmental standards (NO in step S2), it is determined that the purification process is necessary, and it is determined whether the method of the present invention is applicable (step S3).

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

After examining various specific conditions, the construction cost of the present invention is estimated, and whether or not the cost is appropriate, in other words, is more appropriate than the cost when other technologies are employed. Is examined (step S
6). If the cost performance when the method of the present invention is adopted is inferior to the cost performance when other technologies are adopted (step S6).
NO), consider adopting another 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 necessary (Step S7 is YE
S) Perform construction with pH adjustment (step S8) according to another embodiment described later, and if not necessary (step S8)
7 is NO). Construction is performed according to the embodiment of FIG. 1-3 or still another embodiment (step S9).

After completing each process (Step S8 or Step S9), it is examined whether or not the construction result is as desired (Step S10). If the desired result is not obtained (step S10 is NO),
Steps S3 and subsequent steps are repeated, and if a desired result is obtained (YES in Step S10), the necessity of injecting a consolidating agent is considered (Step S11). If it is not necessary to inject the consolidating agent (NO in step S11), the purifying process is ended. If it is necessary to inject the consolidating agent (Y in step S11).
ES) A consolidating agent is injected in a manner described later (step S12), and the purification process ends.

FIGS. 9, 10 and 11 show an example of excavation (perforation) of the injection hole H or the aeration well E shown in FIG. 1-3 in the place where the floor concrete 50 is present. . The concrete core boring machine A1 (FIG. 9) has a core tube 54 to which a diamond bit 52 is attached at the tip. Reference numeral 56 indicates crushed stone below the floor concrete 50. After the circular through hole 60 (FIG. 10) is formed in the floor concrete 50 by the concrete core boring machine A1, the injection hole H or the aeration well E is excavated by the boring machine A2 (FIG. 10). The excavation operation is shown in FIG. Note that FIG.
Denotes a drilling slime.

FIG. 12 shows how the monitor M during the injection of the purifying agent (hydrogen peroxide) is stepped up. In addition, contrary to the order of steps 1, 2, and 3 shown in FIG.
A so-called “step-down” in which steps 3, 2, and 1 descend is also possible.

Although not clearly shown in the embodiment of FIG. 1-12, when the purification by hydrogen peroxide injection has progressed to a certain extent, a consolidating agent is injected, and a large amount of the cleaning agent is applied to the soil. It may be arranged to compensate for the geological disturbance caused by the injection (FIG. 8: loop in which step S11 is YES and step S12).

The chemical reaction for decomposing various contaminants using hydroxyl radicals (OH.) Is effective when performed in an acidic atmosphere (particularly in the range of pH 2 to pH 5). Therefore, in the embodiment of FIGS. 1-12, when the soil G is not in an acidic atmosphere, a pH adjuster (for example, sodium hydrogen sulfate or potassium hydrogen sulfate) is injected before the step of injecting the purifying agent. Then, the soil to be treated may be an acidic atmosphere of pH2 to pH5 (step S7 in FIG. 8 is a loop in which YES is performed and step S8).

[0062]

The effects of the present invention are listed below.

(1) Pollutants in soil can be treated in situ. (2) Even when soil contamination occurs in the various facilities in operation as described above, the soil can be rapidly purified without affecting the operation of the facility. (3) There is no need to remove contaminated soil to the ground and dispose of it. There is no need to excavate contaminated soil, evaporate volatile pollutants into the atmosphere, transport contaminated soil, and disperse pollutants. Pollution is prevented. (4) No harmful compounds are generated during treatment. (5) Once the process is performed, the security is permanent,
There is no need to monitor outflows or leaks of contaminants over time. (6) There is no need to perform wastewater treatment after washing. (7) Many types of pollutants can be treated in large quantities. (8) The problem of ecosystem change is prevented. (9) The restoration period is short.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a construction state of one embodiment of the present invention.

FIG. 2 is a plan view showing an example of an arrangement of an injection hole and an aeration well when the embodiment of FIG. 1 is installed.

FIG. 3 is a view showing an injection or injection step in the embodiment of FIGS.

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

FIG. 5 is a block diagram of a mechanism for treating vaporized contaminants used in the embodiment of FIGS. 1-4.

FIG. 6 is a block diagram showing a purification processing apparatus used in the embodiment of FIGS. 1-5.

FIG. 7 is a table showing a composition of an antioxidant-resistant special material which is a part of the material of the apparatus of FIG. 6;

FIG. 8 is a flowchart showing a construction procedure of the present invention.

FIG. 9 is a diagram showing details of an example of a punching step shown in FIG. 3;

FIG. 10 is a view showing a perforation step at a different stage from FIG. 9;

FIG. 11 is a view showing a perforation step at a different stage from FIGS. 9 and 10;

FIG. 12 is a view showing a step-up / step-down of an implantation step in the embodiment of FIGS. 1-8.

[Explanation of symbols]

 G ・ ・ ・ Soil CA ・ ・ ・ Pollution area WL ・ ・ ・ Groundwater level S ・ ・ ・ Surface H ・ ・ ・ Injection hole E ・ ・ ・ Aeration well M ・ ・ ・ Monitor A ・ ・ ・ Purification equipment R ・ ・・ Rod J ・ ・ ・ Jet of purifying agent (hydrogen peroxide) B ・ ・ ・ Ball (ball valve for channel conversion) HJ ・ ・ ・ High pressure water jet for excavation NH ・ ・ ・ Nozzle 10 ・ ・ ・ Supply hydrogen peroxide System 12 ... Ferrous salt supply system 14 ... Tank for hydrogen peroxide 32 ... Pump for hydrogen peroxide 22 ... Tank for ferrous salt 28 ... Swivel joint A2 ... Boring Machine SM: drilling slime

Continued on the front page (72) Inventor Michio Tsuchi 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Inventor Junichi Kawabata 1-2-7 Moto-Akasaka, Minato-ku, Tokyo No. Kashima Construction Co., Ltd. (72) Inventor Yasushi Machida 1-2-8 Toranomon, Minato-ku, Tokyo Japan Peroxide Co., Ltd. (56) References JP-A-61-114794 (JP, A) 7-75772 (JP, A) JP-A-7-275837 (JP, A) JP-A-6-315675 (JP, A) JP-A-7-185252 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B09C 1/00-1/10 E02D 3/11 A62D 3/00

Claims (2)

(57) [Claims] In a soil purification method for purifying underground soil containing pollutants, the area and depth of a polluted area and the amount of pollutants are investigated for soil to be treated for purification, and the soil is contaminated from the ground surface. In order to decompose pollutants from the monitor while drilling the injection hole and aeration well reaching the bottom of the contaminated area where the soil containing the substance exists and inserting the monitor into the injection hole and changing the depth while rotating Injecting a purifying agent containing hydrogen peroxide, the contaminants are vaporized by the purifying agent, the vaporized contaminants are discharged from the aeration well, and the discharged vaporized contaminants are adsorbed by the adsorption tower and adsorbed. A soil purification method characterized by burning contaminants that could not be removed. 2. A soil purification apparatus for purifying underground soil containing a pollutant, a drilling means for drilling an injection hole and an aeration well from a ground surface to a contaminated area where the soil containing the pollutant exists; An injection monitor for injecting a purifying agent that decomposes the pollutant toward the soil containing the contaminant located inside the injection hole; and an injection monitor for changing the depth of the injection monitor while rotating the injection monitor. A monitor moving means, and a suction means for discharging contaminants vaporized by the purifying agent and discharged from the aeration well from the aeration well, and an adsorption tower for adsorbing the contaminated substances sucked, and adsorbing by the adsorption tower. A high-temperature incinerator that incinerates contaminants that are not removed, and a cooling tower that cools substances generated in the high-temperature incinerator,
The soil purifier further comprises a hydrogen peroxide supply system and a ferrous salt supply system.