JP2002254062A - In situ restoration method and restoration equipment for organic contaminated soil - Google Patents

Abstract

[PROBLEMS] To purify organic soil contaminated by reducing the molecular weight of organic substances such as heavy oil containing oil with a high molecular weight when applying the air sparging method to facilitate the application of the air sparging method. In addition, the present invention provides an in-situ purification method and a remediation device for organic-contaminated soil that can be purified in situ at low cost without excavating and transporting the contaminated soil. SOLUTION: The in-situ restoration method and the restoration apparatus of the organic matter-contaminated soil according to the present invention are characterized in that in the in-situ restoration method of the organic matter-contaminated soil for biologically treating organic matter, air sparging is performed after injecting an oxidizing agent. Biodegradation is facilitated by reducing the molecular weight of organic substances containing oils having a large molecular weight, such as heavy oil. At this time, the oxidizing agent is made liquid or gaseous so that the injection zone is distinguished for efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-situ restoration method and a restoration apparatus for organic-contaminated soil, and more particularly to an in-situ restoration method and an restoration apparatus for organic-contaminated soil, which treats hardly decomposable organic matter so as to easily perform air sparging. About.

[0002]

2. Description of the Related Art In recent years, in soil surveys on a site of a factory due to redevelopment of an urban area, etc., contaminated soil contaminated with organic substances has been exposed in various places, and treatment of the contaminated soil is a social problem. Has become a point.

[0003] In the case of contaminated soil, it is usually repaired by physicochemical methods such as washing / separation and heat treatment and biological methods such as land farming after excavation and removal.

[0004] Further, the contaminated groundwater is recovered by pumping, volatilization and separation by aeration, biological treatment, or adsorption treatment with activated carbon or the like.

[0005] Excavation and unloading of contaminated soil involves not only environmental problems but also a high cost. Therefore, it is also considered to treat the soil in situ without excavating the soil or pumping groundwater. Have been.

As a method of repairing organic matter in situ,
There are methods such as vacuum extraction and bioventing for the unsaturated zone, and for the saturated zone, air is blown into the saturated zone to evaporate contaminants and vacuum extraction in the unsaturated zone. The air sparging method is also common.

[0007] The air sparging method is expected as a restoration method capable of removing and decomposing contaminants in situ without excavating soil. However, an oil component having a large molecular weight has a low volatilization effect and is very biodegradable. slow.

For this reason, when repairing soil contaminated with organic matter containing a high molecular weight oil such as heavy oil, it takes a very long time to complete the restoration completely. In some cases, it cannot be completely disassembled.

However, in order to treat such contaminated soil at an early stage, cleaning or incineration must be performed after excavation and unloading, resulting in very costly purification.

[0010] Therefore, in reality, there has not been proposed an appropriate remediation method capable of in-situ treatment of soil contaminated with a hardly soluble or hardly decomposable organic substance having a large molecular weight.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been proposed in order to solve the problems.
Excavation and removal of contaminated soil by purifying organic matter-contaminated soil by reducing the molecular weight of organic matter containing heavy oil and other high molecular weight oils when applying the air sparging method to facilitate the application of the air sparging method. The present invention provides an in-situ purification method and a remediation device for organic-contaminated soil that can be purified in situ at a low cost.

[0012]

According to a first aspect of the present invention, there is provided an in-situ repair method for an organic substance-contaminated soil in which an organic substance is biologically treated. It is characterized by sparging and facilitates biodegradation by reducing the molecular weight of organic substances such as heavy oils containing oils having a large molecular weight.

According to a second aspect of the present invention, there is provided an in-situ restoration method for organic-contaminated soil, wherein the oxidizing agent is liquidized and injected into an unsaturated zone. It is characterized by the fact that, in addition to the above functions,
The oxidant is lowered to permeate the contaminated soil.

According to a third aspect of the present invention, there is provided an in-situ method for repairing an organic substance-contaminated soil according to the first or second aspect, wherein the oxidizing agent is converted into a gaseous state to a saturated zone. It is characterized by being injected, and in addition to the above functions, raises the oxidizing agent to permeate the contaminated soil.

According to a fourth aspect of the present invention, there is provided an in-situ method for repairing an organic matter-contaminated soil according to any one of the first to third aspects, wherein the in-situ indigenous microorganisms are removed by air. It is characterized by being mixed during sparging, and enhances the activation of microorganisms in contaminated soil.

The in-situ repair apparatus for soil contaminated with organic matter according to the present invention is a repair apparatus for soil contaminated with organic matter, in which an in-situ repair apparatus using an air sparging method is arranged, and the in-situ repair apparatus uses an oxidizing agent. With the injection machine juxtaposed,
The oxidizer injector is divided into a plurality of parts, and at least one oxidizer injector is connected to the sparge well of the in-situ restoration apparatus, thereby facilitating in-situ purification of organic substances in contaminated soil and reducing cost. Purification processing has been achieved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The in-situ purification method and repair apparatus for organic-contaminated soil according to the present invention are basically used in an in-situ repair method for organic-contaminated soil for biologically treating organic matter, after injecting an oxidizing agent and air sparging. It is characterized by reducing the molecular weight of organic matter containing a high molecular weight oil such as heavy oil, thereby facilitating biodegradation and enabling in situ purification. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a repair apparatus for carrying out the present invention for soil contaminated with organic matter.

The repair apparatus 1 according to the present invention is used to purify organic contaminants such as benzene, toluene, xylene, polynuclear aromatics, and machine oils caused by production of petroleum and coal gas. It is based on the application of the air sparging method.

In the present embodiment, contamination from the compressor 2 for injecting air, the sparge well 3 connected to the compressor 2 and reaching the saturated zone 9 and the extraction well 4 arranged in the unsaturated zone is described. The restoration device 1 is composed of a water treatment device 5 for purifying water and a gas treatment device 6.

In the purification process of the restoration apparatus of the present embodiment, basically, air is blown into the saturated zone 9 of the contaminated soil and an oxidizing agent is injected into the unsaturated zone 10, so that oil, which is an organic pollutant, is reduced. Unsaturated zone 10 with molecular contaminated water
Vacuum extraction from the extraction well 4
In addition, by passing through the intake blower 16, respective purification treatments are performed while separating them into contaminated water and contaminated air, thereby purifying them.

The in-situ purification method according to the present invention is shown in FIGS.
In this embodiment, the soil contaminated with organic matter is purified by the following steps.

FIG. 2 shows a process for treating organic contaminated soil before performing air sparging.

In carrying out the treatment step for the organic-contaminated soil, a cover 14 is laid on the surface of the soil to prevent the contaminated air from escaping into the air, and while opening the valve 11 of the injector 7, Valve 1 of compressor 2
3 is closed.

Since the oxidizing agent such as ozone gas and liquid oxidizing agent is stored in the injector 7, the oxidizing agent passes through the sparge well 3 before the air from the compressor 2 is injected into the contaminated soil. It will be injected into the saturation zone 9.

As a result, the oxidizing agent such as ozone gas or liquid oxidizing agent is removed from the saturated zone 9 where oil exists as shown in FIG.
And, by diffusing into the unsaturated zone 10, it decomposes into a low-molecular substance state in which oil having a large molecular weight existing in soil or groundwater can be extracted.

The injection of the oxidizing agent is intermittently performed a plurality of times according to the condition of the contaminated soil, so that the oil content can be reduced to a low molecular weight before the air is injected. In some cases, it is intended to shorten the construction period by performing the injection simultaneously with the air injection.

In the above steps, the processing steps before the air sparging are shown. FIG. 3 shows the organic matter after the oil content is reduced to a low molecular weight and the air sparging is efficiently applied. 3 shows a treatment process for contaminated soil.

In this processing step, the valve 11 of the injector 7 is closed and the valve 13 of the compressor 2 is opened, and the processing by air sparging is performed.

The air from the compressor 2 is blown into the saturated zone 9 of the contaminated soil from the sparge well 3 and the oxidizing agent is injected into the unsaturated zone 10, so that the oil is volatilized while being reduced in molecular weight. It is vacuum-extracted from the extraction well 4 of the unsaturated zone 10 together with water, and is passed through the gas-liquid separator 15 and the intake blower 16 to be subjected to respective purification treatments while being separated into contaminated water and contaminated air. It is trying to make it.

Therefore, in the present embodiment, the air sparging treatment is efficiently performed by reducing the molecular weight of the hardly soluble oil having a large molecular weight to a state capable of biodegradation, and then the organic matter is extracted from the soil. The soil that has been contaminated with organic matter is surely cleaned at the current location.

The type and concentration of the oxidizing agent injected from the injector and the timing of the injection are selected before or simultaneously with the treatment by air sparging, and the injection is performed once or intermittently. The decision as to whether or not to recycle is appropriately adjusted in accordance with the pollutants, concentration level, range of contamination, etc. of the contaminated soil. Can handle a wide range of position processing.

FIG. 4 shows another embodiment of the present invention. In the repairing apparatus 20 shown in the present embodiment, an injector 8 that faces the unsaturated zone 10 is arranged in addition to the repairing apparatus 1 in the above-described embodiment.

The injector 7 is connected to the sparge well 3 via a valve 11, and the injector 8 faces the unsaturated zone 10 via a valve 12, and is located between the compressor 2 and the sparge well 3. The injection extraction operation is performed by opening and closing the valve 13 provided.

In the purification treatment in the repairing apparatus of the present embodiment, an oxidizing agent is injected into the saturated zone 9 and the unsaturated zone 10 before air is blown into the saturated zone 9 of the contaminated soil, so that oil having a large molecular weight can be reduced. The air is sparged efficiently to carry out air sparging, and the oil is vacuum extracted from the extraction well 4 of the unsaturated zone 10 and passed through the gas-liquid separator 15 and the intake blower 16 to remove contaminated water and contaminated air. Each purification process is performed while separating them to achieve purification.

The in-situ purification method of this embodiment is shown in FIG.
6 and the purification of the organic-contaminated soil is performed by the following steps.

FIG. 5 shows a process for treating organic contaminated soil before air sparging is performed.

In carrying out the treatment step for the organic-contaminated soil, a cover 14 is laid on the surface of the soil to prevent contaminated air from escaping into the air.
Compressor 2 while opening valves 11 and 12
Valve 13 is closed.

The injector 7 stores a gaseous oxidant such as ozone gas, and the injector 8 stores a liquid oxidant such as hydrogen peroxide. Before the air is injected into the contaminated soil, a gaseous oxidant is injected into the saturated zone 9 through the sparge well 3 and a liquid oxidant is injected into the unsaturated zone 10 through the valve 12. Become.

As a result, the gaseous oxidizing agent is
From the unsaturated zone 10
As a result, the organic contaminants having a high molecular weight in the soil and groundwater are reduced to a low molecular weight state.

The injection of the oxidizing agent is carried out intermittently a plurality of times according to the condition of the contaminated soil as in the above-described embodiment, so that the low-molecular organic contaminants are injected before the air is injected. However, depending on the situation, it may be intended to shorten the construction period by performing the injection simultaneously with the air injection.

In the above steps, the processing steps before the air sparging is performed are shown. FIG. 6 shows the processing steps for the organic contaminated soil after the air sparging is processed so as to be effective. Is shown.

In this processing step, the valves 1 of the injectors 7 and 8 are used.
The valves 1 and 12 are closed, the valve 13 of the compressor 2 is opened, and a purification process by air sparging is performed.

The air from the compressor 2 is blown from the sparge well 3 into the saturated zone 9 of the contaminated soil,
Since the oxidizing agent is injected into the saturated zone 9 and the unsaturated zone 10, the biologically treated organic matter is mixed with the contaminated water in the unsaturated zone 1.
0 is extracted in vacuum from the extraction well 4 and is passed through the gas-liquid separation device 15 and the intake blower 16 so as to be separated into contaminated water and contaminated air while being subjected to respective purification treatments to achieve purification. .

Therefore, in the present embodiment, the oxidizing agent is separately stored as a gaseous oxidizing agent and a liquid oxidizing agent, so that the saturated zone 9 and the unsaturated zone 1 are stored in accordance with the characteristics.
Since it is injected at zero, soil contaminated with organic matter is reliably cleaned at the current position.

Another embodiment shown in FIG. 7 shows an example of a case where it is determined that the activity of microorganisms indigenous to soil is significantly impaired due to the concentration of the oxidizing agent used or the like.

In the repairing apparatus 30 shown in this embodiment, an extraction well 17 is installed in a place not affected by oxidation in the repairing apparatus 1 of the embodiment shown in FIG. 1, and groundwater is pumped from soil. I have.

Since the pumped groundwater contains active microorganisms, it is mixed with the air injected into the sparge well to supply decomposed microorganisms to the soil which has been recognized as having significantly impaired the activity of the microorganisms.

As a result, the efficiency of biological treatment of the organic matter in the contaminated soil is improved, and the construction period can be shortened.

The in-situ purification method and the remediation device for organic-contaminated soil according to the present invention are configured as described above.
Organic contaminated soil contaminated with organic matter, cyanide and heavy metals can also be reduced by reducing the amount of all contaminants by immobilizing cyanide and heavy metals by insolubilization and increasing the efficiency of air sparging by decomposing cyanide. It is possible to repair the position.

Although the in-situ method and apparatus for repairing soil contaminated with organic matter according to the present invention have been described in detail based on the embodiments, the present invention is not limited to the above-described embodiments. Naturally, various changes can be made within a range not inconsistent with the gist of the invention, that is, air sparging is performed after injecting the oxidizing agent for the kind of the organic substance and the oxidizing agent.

[0052]

According to the first aspect of the present invention, the in-situ restoration method for organic-contaminated soil, which is the invention for in-situ restoration of organic-substance-contaminated soil for biological treatment of organic matter, comprises injecting an oxidizing agent and then performing air sparging. Since it is a feature, the organic matter containing a high molecular weight oil such as heavy oil is reduced in molecular weight to facilitate biodegradation and exhibit the following effects.

Organic contaminated soils that are difficult to volatilize and biodegrade can be repaired in situ. Costs can be reduced compared to work / treatment methods such as excavation, cleaning, and incineration. Since the improvement of the air sparging device is sufficient, the device can be made compact. The maintenance and management of the restoration device is easy and the occurrence of troubles can be reduced.

According to the in-situ restoration method for organic-contaminated soil according to the second aspect of the present invention, in the in-situ restoration method for organic-contaminated soil according to the first aspect, the oxidizing agent is liquefied and injected into the unsaturated zone. Therefore, in addition to the above-mentioned effects, an effect of lowering the oxidizing agent and permeating the contaminated soil is exhibited.

In the in-situ repair method for organic-contaminated soil according to the third aspect of the present invention, in the in-situ repair method for organic-contaminated soil according to the first or second aspect, the oxidizing agent is gasified to form a saturated zone. Since it is characterized by being injected, in addition to the above effects, it has the effect of increasing the oxidizing agent and permeating the contaminated soil.

According to a fourth aspect of the present invention, there is provided an in-situ method for repairing an organic matter-contaminated soil according to any one of the first to third aspects. Since it is characterized by being mixed at the time of sparging, in addition to the above effects, it has the effect of enhancing the activation of microorganisms in contaminated soil.

The in-situ repairing apparatus for soil contaminated with organic matter according to the present invention is a repairing apparatus for soil contaminated with organic matter, wherein the in-situ repairing apparatus is disposed by an air sparging method, and the in-situ repairing apparatus is provided with an oxidizing agent. With the injection machine juxtaposed,
Since the oxidizer injector is divided into a plurality of parts and at least one oxidizer injector is connected to the sparge well of the in-situ restoration apparatus, in-situ purification of organic substances in contaminated soil is facilitated and inexpensive. It has the effect of achieving an effective purification treatment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an in-situ purification method and a remediation device for organic contaminated soil according to the present invention.

FIG. 2 is a process diagram before an air sparging in an in-situ purification method and a restoration apparatus for organic contaminated soil according to the present invention.

FIG. 3 is a diagram showing an air sparging process in an in-situ purification method and a remediation apparatus for organic-contaminated soil according to the present invention.

FIG. 4 is a schematic view of another embodiment of an in-situ purification method and a remediation device for organic-contaminated soil according to the present invention.

FIG. 5 is a process diagram before air sparging in another embodiment of the in-situ cleaning method and the repair apparatus.

FIG. 6 is an air sparging process diagram in another embodiment of the in-situ cleaning method and the repair apparatus.

FIG. 7 is an embodiment diagram showing activation of indigenous microorganisms in the in-situ purification method and the restoration apparatus.

[Explanation of symbols]

1, 20, 30 Restoration device, 2 Compressor,
3 sparge well, 4, 17 extraction well, 5 water treatment device, 6 gas treatment device, 7, 8 injector, 9 saturated zone, 10 unsaturated zone, 11, 12, 13 valve,
14 cover, 15 gas-liquid separator, 16 intake blower,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaharu Tazaki 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation F-term (reference) 2D043 CA20 DA01 EA10 4D004 AA41 AB02 AC07 CA19 CA36 CC01 CC02 CC11

Claims (7)

[Claims] 1. An in situ restoration method for an organic substance-contaminated soil in which an organic substance is biologically treated, the method comprising injecting an oxidizing agent and then performing air sparging. 2. The method according to claim 1, wherein the oxidizing agent is in a liquid state and injected into the unsaturated zone. 3. The method according to claim 1, wherein the oxidizing agent is gaseous and injected into a saturated zone. 4. The method according to claim 1, wherein in situ indigenous microorganisms are mixed during air sparging. 5. An apparatus for repairing soil contaminated with organic matter, comprising: an in-situ repair apparatus by an air sparging method; and an injecting machine for an oxidant in the in-situ repair apparatus by the air sparging method. An in-situ restoration apparatus for organic-contaminated soil, characterized in that the soil is repaired. 6. The in-situ repair apparatus for organic-contaminated soil according to claim 5, wherein the oxidant injector is divided into a plurality of parts and arranged. 7. The in-situ remediation apparatus for organically contaminated soil according to claim 6, wherein at least one oxidizer injector is coupled to the sparge well of the in-situ remediation apparatus.