JP2005161148A - Work and apparatus for cleaning contaminated soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work for cleaning contaminated soil by decontaminating it by using jet grouting. <P>SOLUTION: The work comprises setting a boring machine (1) on the ground above the scope of soil (D) to be cut off, subjecting the soil (D) to a plurality of times of cutting by jet grouting using functional water to soften the soil (D) and to extract the contaminants from the soil (D) with the functional water, inserting an air packer (8) into the area below the soil (D), inflating the air packer (8), and performing air sparging from the lower part of the packer (8) to carry and remove the extracted contaminants. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a contaminated soil purification method and apparatus for purifying contaminants in soil.

  Equipment for drilling boreholes in contaminated soil to purify pollutants in the soil and injecting high-pressure fluid jets, etc. (so-called “monitor”: attached to a supply rod for high-pressure fluid, etc. A member for jetting high-pressure fluid supplied from the ground side to the soil around the borehole (hereinafter the same in this specification)) A technique for purifying pollutants by injecting a high-pressure fluid or the like that increases the efficiency of substance recovery (to the soil around the borehole) has been proposed (see, for example, Patent Document 1).

  In addition, as a so-called jet grouting method, a technique of cutting a predetermined range in the ground by a cross jet of high-pressure liquid from a monitor has been conventionally known (see, for example, Patent Document 2).

For example, in the site of an industrial facility, pollutants are contained over a relatively wide area in the ground, so in order to excavate and purify contaminated soil, huge equipment is required, and as a result, The cost spent on the purification of pollutants becomes enormous.
Here, especially regarding the purification of pollutants contained in a predetermined depth region in the ground, it is desired to treat the contaminated soil in the ground without carrying it out to the ground.
However, a technology that can treat contaminated soil over a wide area without removing it to the ground, and can reliably and easily purify the contaminated soil. Is not proposed at this time.
Japanese Patent No. 3192020 JP-A-7-252823

  The present invention has been proposed to cope with the above-described demands, and can contaminate soil in the ground easily and reliably, and can contaminate soil within a predetermined range. The purpose is to propose a purification method.

According to the purification method of contaminated soil of the present invention, a liquid having a function of improving the efficiency of collecting contaminants is injected into the contaminated soil while controlling the cutting range of the soil to form a mixture with the contaminated soil. The pollutant is entrained by passing air through the mixture, and the air and the pollutant are collected on the ground (claim 1).
The “mixture with contaminated soil” means a mixture of the contaminated soil and the liquid cut by spraying the liquid.

  Further, the present invention controls the cutting range of the soil by injecting a liquid having a function of increasing the efficiency of collecting the pollutant into the soil with a predetermined angle of intersection (so-called cross jet) (Claim 2). ).

In the practice of the present invention, high-temperature water, electrolyzed water, pure water, ozone water, and microorganisms (aerobic microorganisms and / or anaerobic) are used as liquids (hereinafter referred to as functional water) having a function of improving the efficiency of collecting contaminants. Any one of water mixed with nutrients of the sexual microorganism) is used alone or in combination (claim 3).
Here, the high-temperature water has an effect of vaporizing and eluting the target pollutant. Electrolyzed water has the effect of neutralizing contaminants. Since pure water does not contain impurities, it easily dissolves pollutants. Therefore, it has an effect of cleaning and dissolving pollutants well. Ozone water works to oxidize pollutants. The nutrients act to activate microorganisms (aerobic microorganisms and / or anaerobic microorganisms) and decompose pollutants.
That is, the function water, that is, high-temperature water, electrolytic water, pure water, ozone water, and water mixed with aerobic microorganism nutrients, or a combination thereof, that is, decomposition, dissolution, oxidation of pollutants, By using the action of reduction and cleaning, it is possible to improve the efficiency of collecting pollutants. And what kind of functional water should be used should be appropriately selected and determined according to the type, state, construction site status, and other conditions of pollutants.

  In the present invention, air is supplied to the lower part of the mixture of the liquid (functional water described above) having the function of improving the recovery of the pollutant and the contaminated soil (Claim 4).

  The apparatus used in the contaminated soil purification method of the present invention is a double pipe comprising a guide pipe and a pressure feed pipe for pumping air, provided with a packer that expands under pressure near the lower end of the pressure feed pipe, The pipe is connected to a means for collecting air and contaminants (Claim 5).

  Alternatively, a double pipe composed of a guide pipe and a pressure feed pipe for pumping air, a nozzle for spraying liquid by controlling the cutting range of soil on the outer periphery near the tip of the pressure feed pipe, and a packer that expands by pressurization And the guide tube is connected to a means for collecting air and contaminants (Claim 6).

  And the nozzle which controls the cutting range of soil and injects a liquid is plural, and the injection direction of a nozzle intersects with a predetermined angle (Claim 7).

  According to the configuration described above, functional water is jetted from the nozzle as a high-pressure jet, and a predetermined range of cutting is performed, so that a mixture of contaminants and cutting soil is formed in a substantially cylindrical shape in the ground. The contaminants are extracted by functional water, for example, vaporized, precipitated, dissolved, and the like. For example, in the case of soil contaminated with volatile organic compounds (VOC), VOC is vaporized or eluted by high-temperature water.

  Next, a pressure feeding tube is inserted, and air is ejected from below the mixture (contaminant and cutting soil). At that time, air flows out upward in the form of bubbles. The air flowing upward tends to rise along the outer peripheral surface of the pipe, but in the configuration described above, a packer is provided above the air ejection hole, and the air passes through the packer. I can not. Therefore, the air that tends to flow out upward flows out radially outward. As a result, the entire mixture (contaminant and cutting soil) is sparged with air.

Because air flows out radially outward in this way, the mixture of contaminants and cutting soil is sparged by air over the entire area, and the extracted contaminants are entrained upward by bubbles and collected Collected by means.
In addition, for example, aerobic microorganisms can be activated by aeration of the contaminated soil with air ejection, and the pollutants can be decomposed in the long term by the biochemical reaction. In that case, it is preferable to inject a nutrient for microorganisms in advance.

The effect by this invention is shown below.
(1) Pollutants can be removed without excavating the soil. Therefore, huge facilities are not required, and transportation costs, disposal site space, backfill amount, etc. are not required, or much smaller (smaller) than before.
(2) In the short term, the contaminants are entrained and removed by air (sparging), and in the long term, the pollutants are purified by biochemical action by aerobic microorganisms.
(3) If an intersecting jet (described later) is used, the cutting range can be known in advance, and the minimum necessary work may be performed on the contamination range.
(4) Since the air is shut off by the packer, the cutting area can be reliably air sparged.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments for carrying out the invention will be described with reference to the accompanying drawings. Here, in the illustrated embodiment, a case where soil contaminated with VOC such as an organic chlorine-based solvent is purified with high-temperature water will be mainly described.

FIG. 1 shows a ground cutting process by a known jet grout method.
In FIG. 1, the code | symbol D shows the area | region of the contaminated ground of construction object, and the boring machine 1 is installed on the ground S above the construction area D of the contaminated ground. Then, the boring machine 1 drills the boring hole H into the cutting range D of the target ground, and the pipe 2 having the monitor M is inserted into the boring hole H. As described above, the monitor M includes a nozzle (not shown), and the high-pressure liquid jet J is ejected from the nozzle.

  In the illustrated embodiment, high-temperature water of about 80 ° C. is used as the functional water, and the high-temperature water is sent from the ultrahigh pressure pump 5 to the nozzle via the line L1. Further, as will be described later, the compressed air 6 communicates with the pipe 2 (a rod for supplying high-pressure fluid or the like) via a line L2.

  The cutting range L is cut into a cylindrical shape by pulling up the pipe 2 while jetting a jet of high-temperature water from the nozzle of the monitor M while rotating the pipe 2 inserted into the boring hole H. In the cutting range L, the contaminated soil and the functional water are sufficiently mixed to form a mixture (X).

FIG. 2 shows an embodiment using a known cross jet.
As shown in FIG. 3, the monitor M provided at the tip of the pipe 2 is provided with two nozzles N1 and N2 spaced apart from each other, and jets J1 and J2 ejected from the nozzles N1 and N2 have a radius r. Are arranged so as to intersect at a predetermined angle α.
Here, it is known that in a cross jet, the jet diverges in all directions at a point where the jets cross or collide with each other, and the kinetic energy is lost. For this reason, since the kinetic energy sufficient to excavate the soil does not exist in the jet stream outside the portion where the jets intersect each other, the excavation of the soil is not performed. Therefore, the reach distances of the high-pressure liquid jets J1 and J2 are controlled with high accuracy at the position in the radial direction that is the intersection position, that is, at the location of the radius r. Then, by moving the pipe 2 in the vertical direction while rotating, the cutting range L having a substantially cylindrical radius r about the pipe 2 is cut by the jets J1 and J2 constituting the high-difference jet. .

Next, a sparging process using air (air sparging process) will be described with reference to FIG.
First, the double pipes 3 and 4 are inserted into the cutting range L of the contaminated ground D cut in the cutting process. By inserting the double tubes 3 and 4, a bore hole for air injection is formed. Here, as shown in FIG. 4, the inner pipe (pneumatic feed pipe) 3 is inserted to below the cutting range L of the contaminated ground.
A packer 8 that expands and contracts by supplying and discharging compressed air is provided below the cutting range L of the contaminated ground on the outer periphery of the inner tube 3. When the packer 8 is inserted to a predetermined position, the compressed air is supplied (pressurized) to increase the diameter, and the gap with the inner wall surface of the boring hole H is blocked (closed or sealed). As a result, as will be described later, the entire cutting range is exposed to the bubbles from below by the jet.
A strainer 9 is provided in the air ejection hole on the outer periphery of the inner tube 3 below the packer 8 so that fine bubbles are discharged into the ground.
The lower end of the outer tube 4 is positioned above the cutting range L and is configured to collect air and contaminants therein.

  Air is supplied to the inner pipe 3 from a ground air supply source A via a line L3. A collecting means 10 for collecting air and contaminants is provided at the upper end of the outer tube 4, and gas is sucked by a suction device (not shown) through the line L4.

  When air is sent from the air supply source A to the inner tube 3, the air is ejected from the air ejection hole at the tip of the inner tube 3 and flows out upward as bubbles. At this time, the bubbles tend to rise and flow along the inner tube 3, but the gap between the inner tube 3 and the inner wall surface of the boring hole is blocked by the packer 8, and therefore rises along the inner tube 3. The flow of bubbles is blocked. As a result, the bubbles rise after flowing radially outward. Then, as the bubbles flow outward in the radial direction, the rising bubbles pass through substantially all the region of the cylindrical cutting range D. When the bubbles pass through the cylindrical cutting range D, the bubbles entrain the contaminants extracted by the functional water, so that both contaminants and air (bubbles) are formed between the inner tube 3 and the outer tube 4. Ascending, the suction is performed by the collecting means 10.

  The sucked gas is processed as necessary via the line L4 and released to the atmosphere. In this way, contaminants are removed.

Drawing A on the right side of FIG. 5 shows a cutting portion D after the cutting step described in FIG. 1, and this cutting portion D is filled with a mixture X of cut soil and functional water.
When the air purging is performed as described with reference to FIG. 4, a space portion Y is generated by breathing in the upper part of the mixture X of soil and functional water, as shown in the drawing B on the right side. This space portion Y is cleaned by injecting a cleaning agent, and further filled with a filler.

In the above embodiment, the pipe 2 provided with the monitor M is used in the cutting process, and then the pumping pipe 3 that pumps air in the air sparging process is used. However, in the embodiment shown in FIGS. In addition, a pressure feeding tube 3A for pumping liquid is used. In other words, the pressure feeding tube 3A is shared by the cutting process and the air sparging process.
As shown in FIG. 6, the double pipe inner pipe (pumping pipe) 3A is further extended from the tip of the monitor M provided with a nozzle, and is provided with a strainer 9, which is an air ejection hole. A packer 8 is provided above the packer 8.
As shown in the figure, the cutting range L of the contaminated area D is cut by the functional water jet J, and the tip of the pressure feed pipe 3A is inserted below the cutting range L as shown in FIG. The air is supplied from the air source A. The ejected air passes through the entire cutting area by the packer 8, entrains contaminants to the collecting means 10, and purifies the soil.

  Although the present invention can sufficiently purify even in the short term as described above, it is extremely preferable in the long term if the pollutants are decomposed by aerobic microorganisms. In that case, better results can be obtained by injecting nutrients or the like that activate the microorganisms.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

For example, in the above-described embodiment, an example in which contaminated soil due to VOC or the like is purified with high-temperature water has been described. However, the present invention is implemented by selectively using functional water that appropriately corresponds to other various pollutants. be able to.
That is, high-temperature water has an effect of vaporizing and eluting VOC as a target pollutant. For example, when electrolytic water is used as functional water, acidic pollutants can be neutralized and treated. Further, if pure water is selected as the functional water, the pure water does not contain impurities, so it is easy to dissolve the pollutant, and therefore the pollutant can be washed and dissolved well. Further, when the pollutant is alkaline, it is possible to neutralize the alkaline pollutant by rendering ozone water as the functional water. In addition to this, when water mixed with a nutrient is used as functional water, microorganisms in the soil (aerobic microorganisms and / or anaerobic microorganisms) can be activated to decompose the pollutants.

Sectional drawing explaining the ground cutting process in the purification method of the contaminated soil of this invention. Sectional drawing explaining embodiment which constructs the ground cutting process of this invention by a cross jet. The figure explaining the structure of the monitor part of the said FIG. Sectional drawing explaining the air sparging process of this invention. It is explanatory drawing of the state after construction in the cutting range, A is before air sparging, B shows after air sparging. Sectional drawing explaining the ground cutting process by another embodiment of the double-pipe apparatus of this invention. Sectional drawing explaining the air sparging process of the said FIG.

Explanation of symbols

1 ... Boring machine 2 ... Pipe (boring tube)
3 ... Inner pipe (pressure feed pipe)
4 ... Outer pipe (guide pipe)
5 ... High-pressure pump 8 ... Packer 9 ... Strainer 10 ... Air and contaminant collection means D ... Contaminated ground

Claims (7)

  Contamination by injecting liquid into the contaminated soil with a function to increase the efficiency of collecting the pollutant while controlling the cutting range of the soil, forming a mixture with the contaminated soil, and passing air through the mixture A method for purifying contaminated soil, characterized by entraining substances and collecting air and pollutants on the ground.   2. The purification of contaminated soil according to claim 1, wherein the cutting range of the soil is controlled by spraying the liquid having a function of improving the collection of the pollutant with a predetermined angle of intersection in the soil. Construction method.   As a liquid having a function of improving the efficiency of collecting pollutants, any one of hot water, electrolyzed water, pure water, ozone water, and water mixed with aerobic microorganism nutrients is used alone or in combination. The method for purifying contaminated soil according to claim 1 or 2.   The method for purifying contaminated soil according to any one of claims 1 to 3, wherein air is supplied to a lower portion of a mixture of a liquid and a contaminated soil having a function of improving the recovery of the pollutant.   A double tube comprising a guide tube and a pressure feed tube for pumping air, a packer that expands by pressurization is provided near the lower end of the pressure feed tube, and the guide tube is connected to a means for collecting air and contaminants. A double-pipe system used for the purification method of contaminated soil.   A double pipe consisting of a guide pipe and a pressure feed pipe for pumping air, and a nozzle for spraying liquid by controlling the cutting range of the soil and a packer that expands by pressurization are provided on the outer periphery near the tip of the pressure feed pipe A double-pipe apparatus used in a method for purifying contaminated soil, characterized in that a guide pipe is connected to air and contaminant collecting means.   The double-pipe apparatus used for the contaminated soil purification method according to claim 6, wherein there are a plurality of nozzles that spray the liquid by controlling the cutting range of the soil, and the spraying directions of the nozzles intersect at a predetermined angle.

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