JP3166553B2 - How to clean contaminated soil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Various types of wastes have been landfilled on landfill sites and factory sites.
Or by such disposal after use leakage or which in solvents to be used in the factory, there are cases where the ground is generating contaminated soil in the ground is contaminated. These contaminated soils may adversely affect the surrounding environment, and the ground containing such contaminated soils lacks reliability as the foundation ground for various structures. When planning the redevelopment of the site of a factory or the like, if it is discovered that such contaminated soil exists in the ground, it is desirable to immediately purify this and detoxify it. And, the method of purifying such contaminated soil can be generally classified into a method of treating volatile harmful substances or the like in situ and a method of excavating and treating contaminated soil. However, as a method of digging and treating contaminated soil, conventionally, for example, dig out contaminated soil in a sunny place, perform aeration treatment by solar drying or stirring, or use a heating device. There are known methods for volatilizing pollutants.

[0003]

However, according to the above-mentioned conventional method of digging and treating contaminated soil,
Efficient treatment work, such as requiring a large shed to accumulate and purify a large amount of gas containing pollutants that emanates from a large amount of excavated contaminated soil without diffusing into the surroundings In addition, there is a problem that during the treatment operation, the worker must perform the operation for a long time while contacting the contaminated soil.

Accordingly, the present invention has been made in view of such a conventional problem, and it has been proposed that a large amount of excavated contaminated soil be diffused into contaminants volatilized from the contaminated soil to the surroundings.
It is another object of the present invention to provide a method for purifying contaminated soil that can efficiently purify while avoiding contact between the worker and the contaminated soil as much as possible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and the gist of the invention is to provide an air-permeable intake filter member and an air supply filter section.
The contaminated soil stood prime with make prime embedded while contaminated soil timber inside wrapped by the sheet, said sheet
One end of contaminated soil wrapped in heat
Interposed filter chamber filled with filter material
In this filter chamber, connect the air supply pipe
In one, facing one end of the air supply filter member, the
Fresh air supplied from the air pipe is filtered through the filter chamber.
And distributed to each air supply filter member through the contaminated soil
Intake pipe communicating with the intake filter member while feeding
Through the air suction, volatilization from contaminated soil to the air
Transported pollutants to a purification facility
And purifying the contaminated soil by treating the contaminated material.

[0006] It should be noted that the above-described breathable air- absorbing material.
The air filter element, for example, ease passage of air, the perforated pipe, various drain material for drainage, except that it is possible to use a nonwoven fabric or a woven fabric, the porosity large kina crushed stone or gravel or the like Can be laid with a constant width or thickness to form an intake filter member. Here, as the filter material filled in the filter chamber, for example, a perforated pipe, various drainage materials, a nonwoven fabric, a woven fabric, crushed stone, gravel and the like can be used.

Further, in the method for purifying contaminated soil according to the present invention, heated air may be fed into the contaminated soil via the air supply pipe.

[0008]

[Action] Then, according to the method of purifying contaminated soil of the present invention, prime erected contaminated soil after raised digging, together encased by sheets, the air inside the suction by the intake pipe through the intake filter member As a result, the contaminated soil flows air to the intake filter element.
This can prevent the spread of contaminants that evaporate from contaminated soil to the outside of the sheet.
, The volatilized contaminants are carried in the air flow towards the intake pipe through the intake filter member from contaminated soil, while being readily integrated towards the intake pipe, integrated contaminants, to a processing facility It will be immediately fed and will be purified.

The sheet surrounding the contaminated soil may be made of a highly airtight sheet such as a water-blocking sheet which can completely shut off the ventilation between the inside and the outside of the sheet.
At least, in a state in which the flow of air toward the intake filter member is generated by the intake air, if the airtightness is sufficient to prevent the diffusion of the contaminant passing through the sheet to the outside, the fineness is fine. It may have a certain degree of air permeability with holes and gaps.In such a case, fresh air for carrying contaminants is conveyed to the contaminated soil from outside through a sheet by suction by suction. You can also capture.

Further, pollution and intake filter <br/> over member which communicates with the intake pipe, buried respectively and air filter member that communicates the flue inside the contaminated soil, the fresh air through the air feed pipe since the while feeding into the soil via the suction pipe from the contaminated soil so as to suck the air, by placing them appropriately, within the contaminated soil, to carry it contaminants and stripped The air flow is generated at a position and a size suitable for the cleaning, and thereby the contaminated soil can be purified more efficiently.

Furthermore, the one end of the encased contaminated soil by sheet, the filter chamber filled with filter material having air permeability is interposed, with connecting pipe feeding into the filter chamber, feed embedded in contaminated soil With one end of the air filter member facing, fresh air supplied from the air supply pipe is distributed to each air supply filter member via the filter chamber . Therefore , a uniform air flow can be generated over the entire contaminated soil wrapped by the sheet, whereby the contaminated soil can be more efficiently purified . Then, if the heated air is fed into the contaminated soil through the air supply pipe and the air supply filter member, the volatilization of the contaminants from the contaminated soil is promoted, and the contaminated soil can be quickly purified. Will be possible.

[0012]

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2, the contaminated soil 2, which is dug up from such plants the site such as standing prime grounds in the vicinity of the treatment facility 30 contaminants, is covered by the sheet 1, buried within the contaminated soil 2 A situation in which contaminants that volatilize are taken out of the contaminated soil 2 by sucking the internal air through a suction pipe 3 (intake filter member) and fed to the treatment facility 30 for purification treatment is shown. I have.

[0013] That is, contaminated soil 2, for example, various organic chlorine compounds, benzene, those containing contaminants having volatility, such volatile mercury compounds, to the entire circumference of this covered by the sheet 1, first land A water-blocking sheet 1 'on the bottom is laid on the surface, and the contaminated soil 2 is sequentially transported and deposited on the water-blocking sheet 1' using heavy equipment such as a bulldozer or a back hood. Along with this, a plurality of suction pipes 3 each composed of a perforated pipe as an intake filter member are buried at appropriate positions inside the contaminated soil 2, and the ends thereof are projected from the slope of the contaminated soil 2 with the raised portions. It is arranged. Note that the impermeable sheet 1 'laid on the bottom surface is not always necessary when the ground on the bottom surface is low in air permeability and rich in geology.

After a predetermined amount of contaminated soil 2 suitable for one cycle of purification work is laid and its surroundings are shaped, the surroundings are covered with a sheet 1 and wrapped. Here, in the first embodiment, for example, a sheet 1 made of a synthetic resin having micropores is used, and it is difficult to cover the entire contaminated soil 2 with a single sheet at a time. Therefore, a large number of unit sheets divided into a size suitable for construction and transportation are added appropriately at the laying site to wrap the contaminated soil 2. Note that the replenished portions of the sheets do not necessarily need to be in a state in which they are completely in close contact with each other, and may be in a state where a certain gap is formed in the replenished portion.

When the work of wrapping the contaminated soil 2 with the sheet 1 is completed, the suction pipe 5 is connected and connected to one end 3a protruding from the slope of the suction pipe 3 embedded in the contaminated soil 2. The suction pipe 5 is connected to a purification treatment facility 30 including a gas-liquid separation tank 6, a vacuum pump 7, a pollutant absorption tower 8, and the like.
Of the contaminated soil 2 by the operation of the suction pipe 3,
In addition to the integrated suction via the suction pipe 5, the gas is passed through the gas-liquid separation tank 6 and then fed to the pollutant adsorption tower 8. The contaminant adsorption tower 8 is filled with a substance having an action of adsorbing activated carbon and other contaminants, and the contaminants passing therethrough are adsorbed by the adsorbent.

Then, as described above, the contaminated soil 2 is wrapped in the sheet 1, the suction pipe 5 is connected to the suction pipe 3, and the vacuum pump 7 is operated. In the meantime, air from the outside taken in from the fine holes and gaps of the sheet 1 covering the sheet 1 causes a flow of air flowing toward the suction pipe 3, and this flow flows between particles of the contaminated soil 2. When flowing down, volatile contaminants in the contaminated soil 2 are taken in, and the air carrying the contaminants is accumulated in the suction pipe 3 and the suction pipe 5 and is immediately sent to the purification treatment facility 3. become.

In the air carrying the pollutant sent to the purification treatment facility 3, the liquid contained therein is separated by the gas-liquid separation tank 6, and the air passing through the gas-liquid separation tank 6 is evacuated. After absorbing and removing the contaminants introduced into the absorption tower 8 via the pump 7, only purified air is discharged to the outside from the outlet 8 a of the absorption tower 8.

If the purification operation by suctioning air from the contaminated soil 2 is continued for a predetermined time, the concentration of the volatile contaminants in the contaminated soil 2 will gradually decrease. When air is sampled as appropriate and it is confirmed that the concentration of pollutants is below the reference value,
Thereafter, the vacuum pump 7 is stopped, the intake pipe 5 is removed, the sheet 1 is removed, and one cycle of the cleaning operation is completed. It is to be noted that the remaining soil after the completion of the purification work can be backfilled to the original excavation site or left as an embankment.
In addition, the removed equipment can be sequentially diverted to the cleaning operation of the contaminated soil in the next cycle.

According to the example of FIG. 3, when the contaminated soil 2 is to be raised, in addition to the suction pipe 3 serving as a filter member communicating with the suction pipe 5, a porous member serving as a filter member communicating with the air supply pipe 14 is provided. air supply pipe 10 (feed consisting of a tube
The filter member) for the gas, is buried plurality contaminated soil 1, contaminated soil 2 stood prime is covered by water shield sheet 4 rich around the this tightness.

That is, the air supply pipe 10 is connected to the contaminated soil 2.
Is alternately buried between the suction pipes 3, and one end 10 a of the suction pipe 3 projects from the slope opposite to the slope from which the suction pipe 3 projects, and the air supply pipe 14.
The fresh air sent from the air pressure pump 16 can be fed into the contaminated soil 2. The air supply pipe 14 has an adjustment valve 1
2 are provided, whereby the pneumatic pump 1
The amount of air supplied from 6 can be adjusted.

Further, water barrier sheet 4 used in the example of this, for example flexibility made of rubber or a synthetic resin sheet member rich, it is possible to easily cut off the airflow to be passed through it Things. In addition, this water-blocking sheet 4 also wraps the entire contaminated soil 2 in a substantially sealed state by tightly joining a large number of unit sheets having a size suitable for construction and transportation by heat welding or the like at the installation site. It is laid as one.

[0022] Then, according to the example of this, as well as feeding fresh air into contaminated soil 2 by operating the air feeding pump 16, if the suction air from the contaminated soil 2 by operating the vacuum pump 7, pollution Inside the soil 2, an air supply pipe 10
Resulting in airflow toward the suction pipe 3, by going to carry the contaminants that volatile in the contaminated soil 2 in the flow of the air, it is possible to easily purify the contaminated soil 2.

[0023] Incidentally, according to the example of this, the air supply pipe 10 and the suction pipe 3 in the contaminated soil 2, as the flow of air towards the desired direction within the contaminated soil 2 occurs, designing appropriately arranged This enables more efficient purification of contaminated soil, and the adjustment valve 1
By adjusting the supply amount of air to be slightly lower than the suction amount of air by the suction pipe 5, the inside surrounded by the impermeable sheet 4 is always kept in a negative pressure state so that the pollutant is volatilized. , And more efficient purification treatment of contaminated soil can be achieved.

FIG. 4 shows the actual施例of the present invention. In addition, the same reference numerals are given to the same portions as those in each of the above-described examples, and description will be made by using different reference numerals only for newly added portions.

[0025] That is, according to the actual施例this, one end of the water shield sheet 4 ', and contaminated soil 2 encased by water shield sheet 4 for covering the exposed portion on the ground to cover the bottom surface portion, shielding A filter chamber 22 filled with a nonwoven fabric as a filter material is provided between the filter chamber 22 and the water sheet 4. Further, inside the contaminated soil 2, a suction drain 20 made of various drain materials as a filter member is provided.
And the air supply drain 21 are alternately stacked, and one end 20a of the suction drain 20 protrudes from the slope of the contaminated soil 2 and communicates with the air supply pipe 14, while the air supply drain 21 has one end thereof. 21 a is disposed so as to face the filter chamber 22.

[0026] Then, according to the actual施例this, the air becomes that fresh air is supplied to the air drain 21 from the air pipe 14 connected to the filter chamber 22, fed from feed pipe 14 , Flows into each air supply drain 21 through the filter chamber 22, so that the air is substantially evenly distributed to each air supply drain 21, thereby generating a uniform air flow over the entire contaminated soil 2, and further improving the efficiency. It is possible to purify contaminated soil with good quality.

[0027] Note that in the above you施例, feed air from the trachea 14 is supplied to the contaminated soil 2, if feed with heated state, to promote the volatilization of contaminants from contaminated soil 2 Thus, it becomes possible to purify the contaminated soil 2 more quickly.

[0028]

As described above in detail, according to the method for purifying contaminated soil of the present invention, the contaminated soil is raised while embedding a ventilation filter member having air permeability therein. the prime upright contaminated soil wrapped by the sheet, the air sucked through an intake pipe communicating with the intake filter member Thereafter, purification by carrying the volatilized contaminants from the contaminated soil to the flow of air suction Since it is fed to the facility, a large amount of excavated contaminated soil is
It is possible to carry out the purification treatment efficiently while avoiding the diffusion of the pollutants volatilized from the contaminated soil to the surroundings and the contact between the worker and the contaminated soil as much as possible.

An intake filter member communicating with the intake pipe and an air filter member communicating with the air supply pipe are respectively embedded in the contaminated soil, and fresh air is supplied into the contaminated soil. Air is sucked from the contaminated soil while the air is flowing, so that the contaminant is volatilized inside the contaminated soil to create a flow of air suitable for carrying the contaminated material, thereby increasing the efficiency. Contaminated soil can be purified well.

Further, a filter chamber is interposed at one end of the contaminated soil wrapped by the sheet, and fresh air supplied from the air supply pipe is distributed to each filter member through the filter chamber . In addition, a uniform air flow is generated in the entire contaminated soil wrapped by the sheet, so that the contaminated soil can be more efficiently purified.

Further, if the heated air is fed into the contaminated soil through an air pipe and a filter member, the volatilization of the contaminants from the contaminated soil is promoted, and the contaminated soil is purified more quickly. be able to.

[Brief description of the drawings]

1 is a perspective view showing the implementation status of the present invention.

FIG. 2 is a sectional view of the same.

3 is a perspective view showing the implementation status of the present invention.

4 is a sectional view showing the implementation of the real施例of the present invention.

[Explanation of symbols]

 1, 1 ', 4, 4' impermeable sheet 2 contaminated soil 3 suction pipe (intake filter member) 5 intake pipe 7 vacuum pump 10 air supply pipe 14 air supply pipe (intake filter member) 16 air pressure pump 20 suction drain (Intake filter member) 21 Air supply drain (Air supply filter member) 21a One end (Air supply filter member) 22 Filter chamber 30 Purification facility

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-225887 (JP, A) JP-A-5-212366 (JP, A) US Patent 5067852 (US, A) US Patent 5416772 (US, A) U.S. Pat. No. 5,648,62 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B09C 1/04

Claims (2)

(57) [Claims] 1. An air intake filter member and a gas permeable member .
And contaminated soil is buried in a sheet while the filter member for air supply is buried therein, and the buried contaminated soil is wrapped in a sheet , and the contaminated soil is wrapped in the sheet.
One end of the soil is filled with air-permeable filter material
Interposed filter chamber, and in this filter chamber,
Connecting the air supply pipe and the air supply filter member
Facing one end of the fresh air supplied from the air pipe
Filter air through the filter chamber
To the intake soil filter
Air is sucked in through the intake pipe communicating with the
To carry the pollutants volatilized from the contaminated soil.
A method for purifying contaminated soil, comprising treating contaminants by purifying the contaminated soil by feeding the contaminated soil. 2. The humidified air is contaminated through the air supply pipe.
The method for purifying contaminated soil according to claim 1, wherein the contaminated soil is fed into a dye soil .