JPH07280712A - Soil gas extracting method - Google Patents

Abstract

PURPOSE:To provide a soil gas extracting method enabling the extraction of soil gas, containing a volatile organic compound and the like, efficiently at low cost. CONSTITUTION:Soil gas extraction wells 1 are installed in one or plural places to the specified depth from the ground surface to the underground water level or deeper, and combination veils 2 for both pumping and soil gas extraction are installed in one or plural places from the ground surface close to the underground water level. A volatile organic compound and the like existing underground are gasified and extracted along with soil gas by the extraction wells 1, and the pumping of underground water and the extraction of soil gas intermixed with gasified volatile organic compound and the like are performed by the combination wells 2. Soil aeration wells 3 are installed in one or plural places to the specified depth of the underground water level or deeper below the extraction wells 1 and combination wells 2. A volatile organic compound and the like existing at the underground water level or deeper are gasified by the aeration of the soil aeration wells 3 so as to ascend together with soil gas and to be extracted by the extraction wells 1 and combination wells 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extracting soil gas.

[0002]

2. Description of the Related Art In recent years, due to pollution of groundwater by volatile organic compounds (trichloroethylene, tetrachloroethylene, etc.), many wells that cannot be drunk as they are have become a problem all over the country. These substances are used as degreasing agents and the like in many places such as electronic devices, precision machine factories, cleaning stores and the like. Since these materials are harmful to the human body even in an extremely small amount, it has been pointed out that there is a suspicion of a disorder such as internal organs or carcinogenicity. Therefore, conventionally, as a method for purifying soil contaminated with volatile organic compounds and the like, a method has been performed in which volatile organic compounds and the like existing in the ground are made into a gas state and extracted and collected together with soil gas. In the conventional soil gas extraction method, as shown in FIG. 2, after the groundwater in the purification target area is lowered by the pumping well a, the soil gas is sucked from the expanded unsaturated soil layer by the separately provided extraction well b. It was purifying by that. Further, as shown in FIG. 3, a submersible pump may be put in the extraction well to use the well c for both pumping and extraction.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
There are the following problems. That is, the method of FIG. 2 requires a pumping well a dedicated to pumping in addition to the extraction well b.
High cost. In addition, since the gas cannot be extracted and removed by the extraction well b unless the groundwater is lowered by the pumping well a, the working time becomes long.

In the case of the method shown in FIG. 3, since it is necessary to put a pump in the combined well c, the well diameter becomes large and the cost becomes high. Further, the work of switching between pumping and gas extraction is required, which makes the work complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and provides a method for extracting soil gas at low cost and efficiently. To aim.

[0006]

[Means for Solving the Problems] That is, the present invention is to install wells for extracting soil gas at one or more locations from the surface to a predetermined depth above the water table, and to pump water and soil gas from the surface to near the water table. Dual wells for extraction are installed at one or more places, and volatile organic compounds existing in the ground are made into gas by the extraction wells and extracted with soil gas. A method for extracting soil gas, which comprises extracting soil gas mixed with a gaseous volatile organic compound or the like. In addition, up to a predetermined depth below the water table below the extraction well and combined well,
By installing soil aeration wells at one or more locations, by aeration of soil aeration wells, volatile organic compounds and the like existing below the water table are turned into gas, and they are raised together with soil gas. This is a method for extracting soil gas, which is characterized by extraction using a combined well.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. <a> Installation of extraction wells Soil gas extraction wells 1 will be installed at one or more locations to a specified depth above the water table in the area to be purified.
The extraction well 1 uses a tube body equipped with a cylindrical filter-11 at its tip, and is installed by being driven into the ground by a water jet or the like. A ground blower-4 is connected to the installed extraction well 1.

<B> Installation of dual purpose wells Up to near the water table of the area to be purified (at or below the water table), dual wells 2 for pumping water and extracting soil gas are installed at one location or at multiple locations. The dual well 2 is also installed by driving it into the ground with a water jet or the like, using a tubular body equipped with a cylindrical filter 21 at its tip.

When a plurality of extraction wells 1 and multiple wells 2 are installed, they may be installed alternately in the ground at a predetermined interval.
A vacuum pump 5 on the ground is connected to the dual-purpose well 2 installed in the ground, and in the case of a plurality of dual-purpose wells 2, the vacuum pump 5 is collectively connected.

<C> Installation of aeration wells Underground aeration wells 3 are installed at one or more locations up to a predetermined depth below the water table in the area to be purified. The soil aeration well 3 is also installed by being driven into the ground by a water jet or the like by using a tube body having a cylindrical filter 31 at its tip. A compressor 6 on the ground is connected to the aeration well 3.

<D> Soil gas extraction work above the groundwater level After the extraction well 1, the combined well 2 and the aeration well 3 are installed in a predetermined number and in a predetermined position, the blower-4, the vacuum pump 5, and the compressor-6 are installed. Operate. From the unsaturated soil above the water table, the volatile organic compounds and the like existing in the ground become gaseous through the extraction well 1 along with the operation of the blower-4, and are sucked together with the soil gas.

<E> Extraction work of soil gas near the water table and pumping work The operation of the vacuum pump 5 causes the ground water to be pumped through the combined well 2 to lower the ground water level. When the groundwater level drops to a predetermined level and the combined well 2 runs out of water, the soil gas is extracted continuously continuously. As described above, the extraction work of the soil gas by the extraction well 1 and the pumping work and the extraction work of the soil gas by the combined well 2 can be performed in parallel.

<F> Soil gas extraction work below the water table When the air is injected into the aeration well 3 by the compressor 6, the aeration in the soil is performed by the filter 31 at the tip. As a result, volatile organic compounds and the like existing below the water table become gaseous, rise with soil gas, and can be extracted by the extraction well 1 and the combined well 2.

[0014]

Since the present invention is as described above, the following effects can be obtained. <A> It is not necessary to use a well for pumping as in the conventional case, and the cost can be reduced.

<B> By installing the extraction well above the water table, the soil gas can be extracted and removed from the start of the work, and the work efficiency is improved.

<C> Since the pump is not inserted in the well for pumping and extracting water, the diameter of the combined well can be small and the cost can be reduced.

<D> Since the dual-purpose well does not require the conventional switching between pumping and extraction, it is possible to continuously extract and remove groundwater and soil gas containing pollutants.

<E> By using the underground aeration well, volatile organic compounds and the like existing below the water table can be extracted and removed.

<F> Since pumps are not inserted one by one in the combined well, but pumped on the ground all at once, the cost can be reduced.

<G> Since each well is installed by driving the tube body with a water jet or the like, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional technique.

FIG. 3 is an explanatory diagram of a conventional technique.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Imamura 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Corporation

Claims (14)

[Claims] 1. A soil gas extraction well is installed at one or more locations from the surface to a predetermined depth above the water table, and one or more wells for pumping water and soil gas from the surface to near the water table are provided. A method for extracting soil gas, which is characterized in that it is installed at a location, and soil gas is extracted by the extraction well, and groundwater is pumped and soil gas is extracted by the combined well. 2. Soil gas extraction wells are installed at one or more locations from the surface to a predetermined depth above the water table, and one or multiple wells for pumping water and soil gas from the surface to near the water table are provided. The aeration wells are installed at one location or at multiple locations from the surface to a predetermined depth below the water table, and soil gas is extracted by the extraction wells, and groundwater is pumped by the combined wells. A method for extracting soil gas, which comprises extracting soil gas, increasing the soil gas existing below the water table by aeration of the soil aeration well, and extracting the soil gas by the extraction well and the combined well. 3. The soil gas extraction method according to claim 1, wherein the extraction well and the combined well are alternately installed in the ground at a predetermined interval. Gas extraction method. 4. The method for extracting soil gas according to claim 1, wherein the extraction operation of soil gas by the extraction well and the pumping operation and extraction operation of soil gas by the combined well are performed in parallel. A method for extracting soil gas, which is characterized in that 5. The method for extracting soil gas according to any one of claims 1 to 4, characterized in that the extraction well is constituted by a tubular body equipped with a filter at its tip.
Soil gas extraction method. 6. The method for extracting soil gas according to claim 5, wherein the extraction well is driven into the ground by a water jet. 7. The method for extracting soil gas according to any one of claims 1 to 6, characterized in that the combined well is constituted by a pipe body having a filter at the tip thereof.
Soil gas extraction method. 8. The method for extracting soil gas according to claim 7, wherein the combined well is driven into the ground by a water jet. 9. The method of extracting soil gas according to claim 1, wherein the soil aeration well is aerated by injecting air into the soil aeration well by a compressor on the ground. A method for extracting soil gas, which is characterized by being performed. 10. The method for extracting soil gas according to any one of claims 1 to 9, wherein the soil aeration well is constituted by a tubular body equipped with a filter at a tip thereof. Gas extraction method. 11. The method for extracting soil gas according to claim 10, wherein the underground aeration well is driven into the ground by a water jet. 12. The method for extracting soil gas according to any one of claims 1 to 11, wherein the extraction well is configured to extract soil gas with a ground blower. Extraction method. 13. The method for extracting soil gas according to any one of claims 1 to 12, wherein the combined well is configured to continuously pump groundwater and extract soil gas by a vacuum pump on the ground. A method for extracting soil gas, comprising: 14. The method for extracting soil gas according to claim 1, wherein the plurality of combined wells are collectively connected to a ground vacuum pump, and the vacuum pump pumps groundwater and soil. A method for extracting soil gas, which is characterized in that the gas is continuously extracted.