JP4671073B2 - In-situ repair method for soil contaminated with organic matter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the original position restoration method of the organic matter contaminated soil, particularly relates to the original position restoration method of the organic matter contaminated soil treating hardly decomposable organic matter so as to facilitate air sparging.
[0002]
[Prior art]
In recent years, in ground surveys at factory sites, etc., due to redevelopment of urban areas, etc., there have been situations in which contaminated soil contaminated with organic matter is exposed in various places, and disposal of contaminated soil has become a social problem. .
[0003]
In the case of contaminated soil, after excavation and removal, the soil is usually restored by a physicochemical method such as cleaning / separation or heat treatment, or a biological method such as land farming.
[0004]
In addition, the contaminated groundwater is volatilized and separated by aeration after pumping, or is repaired by biological treatment, adsorption treatment with activated carbon, or the like.
[0005]
And, since excavation and removal of contaminated soil includes environmental problems and costs are also high, it is also considered that excavation of soil and pumping of groundwater are performed in situ, without processing the soil. .
[0006]
In-situ organic restoration methods include vacuum extraction and bioventing for the unsaturated zone. When the saturated zone is targeted, pollutants can be obtained by blowing air into the saturated zone. while volatilize, air sparging method for vacuum extraction with unsaturated zone is also common.
[0007]
The air sparging method is expected as a restoration method that can remove and decompose pollutants in situ without excavating the soil, but oil components with large molecular weight have low volatilization effect and biodegradation is very slow.
[0008]
Therefore, when repairing soil contaminated with organic matter containing heavy oil such as heavy oil, it takes a lot of time to complete the repair, or depending on the case Sometimes it cannot be disassembled at all.
[0009]
Therefore, in order to treat such contaminated soil at an early stage, after excavating and carrying out, there is no choice but to wash or incinerate, which is very costly purification.
[0010]
Therefore, the actual situation is that no suitable repairing method that can perform in-situ treatment has been proposed for soil contaminated with hardly soluble or hardly decomposable organic matter having a large molecular weight.
[0011]
[Problems to be solved by the invention]
The present invention is proposed in order to solve the above problems in view of the above problems, and when purifying organic matter-contaminated soil, the organic matter containing a high molecular weight oil such as heavy oil is reduced when the air sparging method is applied. and molecular weight, to facilitate the application of air sparging method, providing situ cleanup how the organic contaminated soil which can be inexpensively purified in situ without digging out contaminated soil.
[0012]
[Means for Solving the Problems]
The in-situ restoration method for organic matter-contaminated soil according to claim 1 is the in-situ restoration method for organic matter-contaminated soil in which organic matter is biologically treated. After injecting a liquid oxidant into the unsaturated zone , air is saturated. It is characterized by air sparging by being blown into a belt, and biodegradation is facilitated by reducing the molecular weight of organic substances such as heavy oil containing oil having a large molecular weight.
[0013]
The in-situ restoration method for organic matter-contaminated soil according to claim 2 is the in-situ restoration method for organic matter-contaminated soil according to claim 1, wherein indigenous microorganisms in the in- situ region are mixed during air sparging. It is characterized, and enhance the activity of microorganisms in the contaminated soil.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Situ remediation how the organic contaminated soil according to the present invention basically in organics biological treatment situ repair method for organic contamination soil, the liquid oxidant was injected into the unsaturated zone, saturated zone air It is characterized in that it is blown into air and air sparged, and organic substances containing a large molecular weight oil such as heavy oil are reduced in molecular weight to facilitate biodegradation and enable in-situ purification.
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0018]
FIG. 1 is a schematic view showing a repair device for carrying out the present invention on soil contaminated with organic matter.
[0019]
In order to purify organic pollutants such as oil such as benzene, toluene, xylene, polynuclear aromatics, machine oil, etc. resulting from oil and coal gas production, the repair device 1 for carrying out the present invention is air sparging. Based on the application of the law.
[0020]
In the present embodiment, the contaminated water from the compressor 2 for injecting air, the sparge well 3 connected to the compressor 2 and reaching the saturation zone 9 and the extraction well 4 arranged in the unsaturated zone is purified. from a water treatment device 5 for gas treatment device 6 which constitute the repair apparatus 1.
[0021]
The purification process in the repair device of the present embodiment basically reduces the oil content of organic pollutants by blowing air into the saturated zone 9 of the contaminated soil and injecting an oxidant into the unsaturated zone 10. It is vacuum-extracted from the extraction well 4 in the unsaturated zone 10 together with the contaminated water, and through the gas-liquid separation device 15 and the intake blower 16, the respective purification processes are performed while separating the contaminated water and the contaminated air. We are trying to clean.
[0022]
The in-situ purification method according to the present invention is carried out according to the embodiment shown in FIGS. 2 and 3 and purifies organic-contaminated soil by the following steps.
[0023]
Figure 2 shows the process steps for organic contamination soil before performing the air sparging.
[0024]
When carrying out a treatment process for organic matter-contaminated soil, a cover 14 is laid on the surface of the soil to prevent the contaminated air from escaping into the air, while the valve 11 of the injector 7 is opened and the compressor 2 The valve 13 is closed.
[0025]
Thus, since the oxidizer such as ozone gas and liquid oxidizer is stored in the injector 7, the oxidizer is saturated through the sparge well 3 before the air from the compressor 2 is injected into the contaminated soil 9. Will be injected.
[0026]
By diffusing oxidizers such as ozone gas and liquid oxidizer into the saturated zone 9 and the unsaturated zone 10 where oil is present as shown in the figure, oil having a large molecular weight in soil and groundwater is obtained. It breaks down into a state of extractable low molecular weight material.
[0027]
And, the injection of the oxidant is carried out intermittently over a plurality of times according to the situation of the contaminated soil, so that the low molecular weight of the oil is surely performed before the injection of air, but depending on the situation, It is also intended to shorten the construction period by carrying out it simultaneously with the air injection.
[0028]
In the above step, the treatment step before air sparging was shown, but FIG. 3 shows the organic matter-contaminated soil after being treated so that the oil content is reduced and the application of air sparging becomes efficient. The processing steps are shown.
[0029]
In this processing step, the valve 11 of the injector 7 is closed, the valve 13 of the compressor 2 is opened, and processing by air sparging is performed.
[0030]
The air from the compressor 2 is blown from the sparge well 3 into the saturated zone 9 of the contaminated soil and the oxidant is injected into the unsaturated zone 10. Vacuum extraction is performed from the extraction well 4 in the saturation zone 10, and through the gas-liquid separation device 15 and the intake blower 16, the respective purification processes are performed while separating the contaminated water and the contaminated air to achieve purification. ing.
[0031]
Therefore, in the present embodiment, the air sparging process is efficiently performed by reducing the low-solubility oil with a large molecular weight to a low molecular weight and processing it into a biodegradable state, and then the organic matter is extracted from the soil and purified. and it has been, a soil that is organic contaminants are reliably cleaned at the current position.
[0032]
Then, the type and concentration of the oxidant injected from the injector, the choice of whether to inject before or simultaneously with the process by air sparging, and further, the injection is performed once or intermittently multiple times As to whether or not the soil is contaminated with organic matter, it can be adjusted appropriately according to the pollutant, concentration level, and extent of contamination of the contaminated soil, and can be flexibly handled according to the situation. Can handle a wide range.
[0033]
Another embodiment of the present invention is shown in FIG.
In the repairing device 20 shown in the present embodiment, an injector 8 is arranged to face the unsaturated zone 10 in addition to the repairing device 1 in the above-described embodiment.
[0034]
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 provided between the compressor 2 and the sparge well 3. The injection and extraction operation is performed by opening and closing the valve 13.
[0035]
The purification process in the repair device of the present embodiment reduces the molecular weight of oil having a large molecular weight by injecting oxidant into the saturated zone 9 and the unsaturated zone 10 before blowing air into the saturated zone 9 of the contaminated soil. Implementation of air sparging is efficient, and oil is vacuum-extracted from the extraction well 4 in the unsaturated zone 10 and is separated into polluted water and polluted air via the gas-liquid separator 15 and the intake blower 16. However, each purification process is applied to achieve purification.
[0036]
The in-situ purification method of the present embodiment is implemented by the embodiment shown in FIGS. 5 and 6, and purifies organic matter-contaminated soil by the following steps.
[0037]
Figure 5 shows the processing steps for the organic matter contaminated soil before carrying out the air sparging.
[0038]
When carrying out the treatment process for organic matter contaminated soil, a cover 14 is laid on the surface of the soil to prevent the contaminated air from escaping into the air, while opening the valves 11 and 12 of the injectors 7 and 8. The valve 13 of the compressor 2 is closed.
[0039]
The injector 7 stores a gaseous oxidizer such as ozone gas, and the injector 8 stores a liquid oxidizer such as hydrogen peroxide. Before being injected into the contaminated soil, a gaseous oxidant is injected into the saturation zone 9 through the sparge well 3 and a liquid oxidant is injected into the unsaturated zone 10 through the valve 12.
[0040]
As a result, the gaseous oxidant ascends and diffuses from the saturation zone 9 and the liquid oxidant descends from the unsaturated zone 10 so that organic pollutants having a large molecular weight in soil and groundwater can be extracted. Processed into a low molecular state.
[0041]
Then, the injection of the oxidizing agent is intermittently carried out a plurality of times according to the state of the contaminated soil as in the above embodiment, so that the organic pollutants can be reduced in molecular weight before the air injection. However, depending on the situation, it is also intended to shorten the construction period by carrying out the integration simultaneously with the air injection.
[0042]
In the above steps, the processing steps before the air sparging are shown, but FIG. 6 shows the processing steps for the organic polluted soil after being processed so that the application of the air sparging becomes efficient. .
[0043]
In this processing step, the valves 11 and 12 of the injectors 7 and 8 are closed, the valve 13 of the compressor 2 is opened, and a purification process by air sparging is performed.
[0044]
The air from the compressor 2 is blown from the sparge well 3 into the saturated zone 9 of the contaminated soil, and the oxidant is injected into the saturated zone 9 and the unsaturated zone 10, so that the biologically treated organic matter is mixed with the contaminated water. It is vacuum-extracted from the extraction well 4 in the unsaturated zone 10 and is purified by passing through the gas-liquid separator 15 and the intake blower 16 to separate the contaminated water and the contaminated air, respectively. I am trying.
[0045]
Therefore, in the present embodiment, the oxidant is separately classified into the gaseous oxidant and the liquid oxidant and stored separately, and injected into the saturated zone 9 and the unsaturated zone 10 while matching the characteristics. since, the soil that is organic contaminants are reliably cleaned at the current position.
[0046]
Another embodiment shown in FIG. 7 shows a countermeasure example in the case where it is determined that the activity of microorganisms indigenous in the soil is significantly impaired due to the concentration of the oxidant used.
[0047]
In the repair device 30 shown in the present embodiment, the extraction well 17 is installed at a location not affected by oxidation in the repair device 1 of the embodiment shown in FIG. 1 to pump groundwater from the soil.
[0048]
Since pumped groundwater contains active microorganisms, it is mixed with the air injected into the sparge well to supply decomposing microorganisms to the soil where the activity of the microorganisms is recognized to be significantly impaired.
[0049]
Thereby, the efficiency of biological treatment of organic matter in the contaminated soil is improved, and the construction period can be shortened.
[0050]
Situ remediation how the organic contaminated soil according to the present invention, which is configured as described above, organic, even for organic contaminated soil that is contaminated with cyanide and heavy metals, by insolubilization of cyanide and heavy metals By improving the efficiency of the air sparging process by immobilizing and decomposing cyanide compounds, it is possible to restore all contaminants in place.
[0051]
As mentioned above, the in-situ restoration method for organic matter-contaminated soil according to the present invention has been described in detail based on the embodiment thereof, but the present invention is not limited to the above embodiment, and the organic matter and the oxidizing agent are not limited. It is a matter of course that various modifications can be made within the range that does not contradict the spirit of the invention, that is, after injecting a liquid oxidant into the unsaturated zone for the type, etc. , air is sparged into the saturated zone. .
[0052]
【The invention's effect】
The in-situ restoration method for organic matter-contaminated soil according to claim 1 is the in-situ restoration method for organic matter-contaminated soil in which organic matter is biologically treated. After injecting a liquid oxidant into the unsaturated zone , air is saturated. Since it is characterized by air sparging by blowing into a belt, biodegradation is facilitated by reducing the molecular weight of an organic substance containing a large molecular weight oil such as heavy oil, and the following effects are exhibited.
[0053]
(1) volatilization and biodegradation can be repaired in situ difficult organic matter contaminated soil.
(2) Cost can be saved compared to work / treatment methods such as excavation, cleaning, and incineration.
(3) it can be configured the device compact because it requires an improvement of the air sparging unit.
(4) Maintenance of the repair device is easy and trouble can be reduced.
(5) lowering the oxidant attained penetration into contaminated soil soil.
[0054]
The in-situ restoration method for organic matter-contaminated soil according to claim 2 is the in-situ restoration method for organic matter-contaminated soil according to claim 1, wherein indigenous microorganisms in the in- situ region are mixed during air sparging. Since it is a characteristic, in addition to the above-described effects, it exerts an effect of enhancing the activation of microorganisms in the contaminated soil .
[Brief description of the drawings]
FIG. 1 is a schematic view of an in-situ purification method and a repair device for organic matter-contaminated soil according to the present invention. FIG. 2 is a process diagram before air sparging in an in-situ purification method and a repair device for organic matter-contaminated soil according to the present invention. FIG. 4 is a schematic diagram of another embodiment of the organic matter-contaminated soil in-situ purification method and repair apparatus according to the present invention. FIG. 6 is a process diagram before air sparging in another embodiment of the position purifying method and the repairing apparatus. FIG. 6 is an air sparging process diagram in another embodiment of the in situ cleaning method and the repairing apparatus. Diagram showing activation of indigenous microorganisms in Japan 【Explanation of symbols】
1, 20, 30 Repair device, 2 Compressor, 3 Sparge well,
4, 17 Extraction well, 5 Water treatment device, 6 Gas treatment device,
7, 8 injector, 9 saturation zone, 10 unsaturated zone,
11, 12, 13 valve, 14 cover, 15 gas-liquid separator,
16 Intake blower,

Claims (2)

An in-situ restoration method for organic-contaminated soil that biologically treats organic matter, in which liquid oxidant is injected into the unsaturated zone and then air is sparged by blowing air into the saturated zone. Position repair method. 2. The in-situ restoration method for organic-contaminated soil according to claim 1, wherein the indigenous microorganisms are mixed at the time of air sparging .

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