JP2002307048A - Soil cleaning method and soil cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil cleaning method capable of efficiently cleaning polluted soil positioned under an unpolluted soil layer, and a soil cleaning apparatus used therein. SOLUTION: The soil cleaning method consists of a process for forming an excavated hole 4 having depth allowing the nozzle provided to the rotary shaft 22c, which constitutes the excavation part of the soil cleaning apparatus 20, to reach polluted soil by rotating the rotary shafts 22c, a process for excavating the polluted soil by ejecting an extraction solution having extraction action and air from the nozzle while rotating the rotary shaft 22c under high pressure to form a space 5, and discharging the polluted soil as cut earth and sand 1c along with the extraction solution through the excavated hole 4, a solid-liquid separation process for separating cut earth and sand 1c into a liquid containing the pollutant and the extraction solution and cleaned soil and a process for ejecting cleaned soil from the nozzle to fill the space 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil purification method and a soil purification apparatus, and more particularly, to a soil purification method and a soil purification method capable of efficiently purifying contaminated soil located below uncontaminated soil. The present invention relates to a soil purification device suitably used in a purification method.

[0002]

2. Description of the Related Art In recent years, purifying soil contaminated with heavy metals such as cadmium and organic compounds such as trichloroethylene has become an important issue. As a general method of purifying contaminated soil, there is a method of excavating contaminated soil and removing contaminants in the excavated contaminated soil.

[0003]

However, according to the above-mentioned method for purifying contaminated soil, if uncontaminated soil is present in the upper layer of contaminated soil, the uncontaminated soil must be moved before being moved to the lower layer of the uncontaminated soil. Can not purify contaminated soil. For this reason, it is necessary to provide a process for moving uncontaminated soil, such as a process for excavating uncontaminated soil that does not need to be purified and a process for backfilling the space formed by excavating uncontaminated soil. And it takes a lot of trouble.

[0004] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a soil purification method capable of efficiently purifying contaminated soil located below uncontaminated soil. Another object of the present invention is to provide a soil purification apparatus suitably used in the above soil purification method.

[0005]

In order to solve the above-mentioned problems, a soil purification method according to the present invention is a soil purification method for purifying contaminated soil located below uncontaminated soil using a soil purification device. Rotating a rotary shaft that constitutes an excavation section of the soil purification device to form a drilling hole having a depth at which a nozzle provided on the rotary shaft reaches the contaminated soil; and rotating the rotary shaft. By injecting the extraction solution and air having an extraction action and air at a high pressure from the nozzle while excavating, the contaminated soil is excavated to form a space, and the contaminated soil is extracted with the extraction solution as cutting earth and sand through the excavation hole. Discharging step, the step of solid-liquid separation of the cut soil and the liquid containing the contaminant and the extraction solution, and purified soil, and jetting the purified soil from the nozzle to discharge the inside of the space. Characterized in that it comprises a step of performing back fit.

According to such a soil purification method, it is possible to purify the contaminated soil located below the uncontaminated soil without moving the uncontaminated soil. There is no need to provide a process for moving uncontaminated soil, which has been a problem because it takes much time and effort. Therefore, the contaminated soil located below the uncontaminated soil can be efficiently purified. Moreover,
In this soil purification method, by extracting the contaminated soil by excavating the contaminated soil and forming a space by injecting an extraction solution having an extraction action and air at a high pressure from the nozzle while rotating the rotation shaft, the nozzle is operated at a high pressure from the nozzle. The injected extraction solution excavates the contaminated soil and simultaneously extracts the contaminants contained in the contaminated soil. Therefore, in order to extract contaminants, there is no need to prepare a device for crushing the contaminated soil, a device for stirring and mixing the contaminated soil with the extraction solution, or to provide a separate process for extracting the contaminants. No need to extract pollutants. Furthermore, in the above-mentioned soil purification method, when excavating contaminated soil, the contaminated soil is finely crushed and dispersed in the extraction solution, so that the contaminants contained in the contaminated soil can easily come into contact with the extraction solution. Thus, the pollutants contained in the contaminated soil can be easily and surely brought into contact with the extraction solution, and the pollutants contained in the contaminated soil can be extracted very effectively.

In the above-mentioned soil purification method, the nozzle comprises two sets of nozzles provided at intervals in the longitudinal direction of the rotating shaft, and one of the two sets of nozzles is provided. It is desirable to perform the backfill in the space by injecting the purified solution from the other set of nozzles while forming the space by injecting the extraction solution and air at a high pressure from the nozzles.

According to such a soil purification method, since the space can be backfilled while the space is formed, the contaminated soil located below the uncontaminated soil can be more efficiently purified. be able to.

In the above soil purification method, it is preferable that the extraction solution is an aqueous solution containing at least one selected from a chelating agent, an acid, an alkali, and a salt. By adopting such a soil purification method, contaminants contained in contaminated soil can be effectively and easily extracted.

[0010] In order to solve the above-mentioned problems, a soil purification apparatus of the present invention has a rotating shaft and a nozzle provided on the rotating shaft. Excavating part which is capable of being locally excavated by injecting with high pressure, and capable of being locally backfilled by injecting soil from the nozzle while rotating the rotating shaft, A drive unit that drives the excavation unit, a supply unit that supplies the extraction solution, the air, and the soil that are ejected from the nozzle,
Discharging means for discharging the cutting sand excavated in the excavating section,
And a solid-liquid separating means for separating the cut soil into liquid and purified soil.

The above-mentioned soil purification apparatus can excavate locally by injecting the extraction solution and air at a high pressure from the nozzle while rotating the rotating shaft. It is equipped with an excavated part that can be backfilled locally by injecting soil from, so that the contaminated soil located below the uncontaminated soil is purified without moving the uncontaminated soil Therefore, it is not necessary to provide a step for moving uncontaminated soil unlike the conventional soil purification method. Therefore, if the above-mentioned soil purification device is used, it is possible to efficiently purify the contaminated soil located below the uncontaminated soil.

In the above soil purification apparatus, the nozzles are two sets of nozzles provided at intervals in the longitudinal direction of the rotating shaft, and of the two sets of nozzles,
Desirably, one set of nozzles performs excavation and the other set of nozzles performs backfill.

[0013] Since such a soil purification apparatus is capable of backfilling the space while forming the space, the soil purification device located below the uncontaminated soil is more efficiently purified. It is possible to

In the above-mentioned soil purification apparatus, each of the two sets of nozzles may be composed of one nozzle or a plurality of nozzles. Determined according to conditions.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
However, the embodiments described below are specifically described for easy understanding of the purpose of the present invention, and do not limit the present invention unless otherwise limited. 1 to 6 are diagrams for explaining an example of the soil purification method of the present invention, and FIGS. 1 to 5 are schematic diagrams showing the purification status of contaminated soil. It is a flow chart for explaining a process after having discharged as cutting earth and sand.

1 to 5, reference numeral 20 denotes a soil purification apparatus of the present invention. This soil purification device 20
Is a drive unit 21, a digging unit 22, a supply unit 23, a pump 3 serving as a discharging means for discharging the cut sand excavated in the digging unit 22, and a not shown for separating the cut sand into liquid and purified soil. And solid-liquid separation means.

The excavating section 22 includes a rotating shaft 22c and a rotating shaft 2c.
2c. The nozzles are composed of two sets of nozzles, an upper nozzle 22a and a lower nozzle 22b, which are provided at intervals in the length direction of the rotating shaft 22c. Of the two sets of nozzles, the upper nozzle 22a is excavated. The lower nozzle 22b performs backfilling. The drive unit 21 is provided with a motor and the like, and drives the excavation unit 22. The supply unit 23 supplies an extraction solution, air, and purified soil injected from the upper nozzle 22a or the lower nozzle 22b.

Next, a method for purifying the contaminated soil 1 located below the uncontaminated soil 6 by using the soil purifying apparatus 20 will be described in detail. First, the soil purification device 20
Is set on the uncontaminated soil 6 located in the upper layer of the contaminated soil 1. Then, as shown in FIG. 1, the rotary shaft 22 c of the soil purification device 20 is rotated to form the excavation hole 4 having a depth at which the upper nozzle 22 a reaches the lower end 1 b of the contaminated soil 1.

Subsequently, an extraction solution having an extraction action and air are supplied from the supply section 23 into the excavation section 22 and
, And as shown in FIG.
c while rotating the extraction solution and air
The space 5 is formed by locally excavating the contaminated soil 1 located in the lower layer of the uncontaminated soil 6 by injecting the high pressure from a. Simultaneously with the excavation of the contaminated soil 1, contaminants contained in the contaminated soil 1 are extracted by the extraction solution. The contaminated soil 1 is finely crushed when the contaminated soil 1 is excavated and dispersed in the extraction solution, so that the contaminants contained in the contaminated soil 1 can easily come into contact with the extraction solution. . And the excavated contaminated soil 1 is
It is discharged onto the uncontaminated soil 6 through the borehole 4 together with the extraction solution, and is discharged as the cut soil 1 c using the pump 3.

The extraction solution used here is contaminated soil 1
Extract that has the function of extracting pollutants contained in
Any liquid can be used, but chelating agents, acids,
Aqueous solution containing at least one selected from alkali and salt
And the contamination contained in the contaminated soil 1
Determined according to the substance. For example, contained in contaminated soil
Pollutant is Cd²⁺, Pd²⁺, Zn²⁺, Cu ²⁺Such
Complex with an acid having a pH of about 3 to 5
Salt (Cl^-, EDTA, citric acid)
It is desirable. In addition, pollutants contained in contaminated soil
Quality is chromic acid, arsenous acid, arsenic acid, selenic acid, selenious acid
If it is a heavy metal anion, such as an acid of about pH 1 or
Is preferably an alkaline solution having a pH of 11 or more.
Also, the contaminant contained in the contaminated soil is mercury
Then I_TwoAnd I^-And a mixed solution of

Then, the excavation of the contaminated soil 1 is advanced, and the excavation part 22 is gradually raised at a speed according to the excavation condition of the contaminated soil 1 so that the lower nozzle 22b reaches the lower end 1b of the contaminated soil 1 ( When the depth reaches the bottom of the space 5), backfilling in the space 5 is started as shown in FIG.

For backfilling in the space 5, purified soil obtained by purifying the contaminated soil 1 is used. As shown in FIG. 6, the purified soil is obtained by solid-liquid separation (S3) of the cut soil 1c (S1) to be separated from the liquid (S6) containing the pollutant and the extraction solution. . The solid-liquid separation here is performed, for example, by a method using a filter press or the like. The purified soil (S4) thus obtained is supplied from the supply unit 23 to the excavation unit 22.
And is injected from the lower nozzle 22b as shown in FIG. 3, and is locally backfilled in the space 5 (S
5), forming body 10 is formed.

Then, as shown in FIG.
While the excavation of the contaminated soil 1 is proceeding by 2a, the backfilling of the space 5 by the lower nozzle 22b is promoted, and the excavation part 22 is further raised at a speed according to the excavation condition of the contaminated soil 1, and the upper nozzle 22a When the depth reaches the upper end 1a of the soil 1, the excavation of the contaminated soil 1 is completed. Thereafter, only the backfilling in the space 5 by the lower nozzle 22b is advanced, and the excavation part 22 is further raised at a speed according to the backfilling situation, and as shown in FIG. When the depth reaches the upper end 1a (the depth reaches the ceiling of the space 5), the backfilling in the space 5 ends.

Thereafter, the excavating part 22 is further raised,
By performing backfilling in the excavation hole 4, purification of the contaminated soil 1 is completed.

According to such a soil purification method, the contaminated soil 1 located below the uncontaminated soil 6 can be purified without moving the uncontaminated soil 6. The located contaminated soil 1 can be efficiently purified. Moreover, in this soil purification method, the rotating shaft 2
2c while rotating the extraction solution and air with the upper nozzle 2
2a, the space 5 is formed by excavating the contaminated soil 1 by injecting it with high pressure.
Since the contaminated soil 1 is excavated and the contaminants contained in the contaminated soil 1 are extracted at the same time as the contaminated soil 1 is excavated by the extraction solution injected from 2a at high pressure, there is no need to extract the contaminants.

Further, in the above-mentioned soil purification method, when excavating the contaminated soil 1, the contaminated soil 1 is finely crushed and dispersed in the extraction solution, and the contaminants contained in the contaminated soil 1 easily come into contact with the extraction solution. Soil 1
And the extraction solution can be easily and surely brought into contact with the contaminants contained in the contaminated soil 1, and the contaminants contained in the contaminated soil 1 can be extracted very effectively.

The nozzles are composed of two sets of nozzles, an upper nozzle 22a and a lower nozzle 22b, provided at intervals in the length direction of the rotating shaft 22c.
a, while the space 5 is formed by injecting the extraction solution and air at a high pressure, the purified soil can be injected from the lower nozzle 22b to backfill the space. The contaminated soil 1 located in the lower layer can be more efficiently purified.

In addition, the above-mentioned soil purification apparatus has a rotating shaft 22.
It is possible to excavate locally by injecting the extraction solution and air from the upper nozzle 22a at high pressure while rotating c, and by injecting the soil from the lower nozzle 22b while rotating the rotation shaft 22c. Since it is provided with the excavated portion 22 that can be backfilled locally, the contaminated soil 1 located below the uncontaminated soil 6 can be purified without moving the uncontaminated soil 6. Thus, the contaminated soil 1 located below the uncontaminated soil 6 can be efficiently purified.

In the above soil purification method, while the space 5 is formed by injecting the extraction solution and air from the upper nozzle 22a at a high pressure, the purified soil is ejected from the lower nozzle 22b while the space 5 is formed. Backfilled,
After forming the space 5 by injecting the extraction solution and air at high pressure from the upper nozzle 22a, the lower nozzle 22b
The space may be backfilled by injecting more purified soil. In this case, the jetting of water and air at high pressure and the jetting of the purified soil may be performed by one nozzle, and the rotary shaft 22c may be provided with one nozzle.

[0030]

As described above in detail, according to the soil purification apparatus and the soil purification method using the same of the present invention, the contaminated soil located below the uncontaminated soil without moving the uncontaminated soil. , It is possible to efficiently purify contaminated soil located below the uncontaminated soil. In addition, this soil purification method is a method of excavating the contaminated soil to form a space by injecting an extraction solution having an extraction action and air at a high pressure from the nozzle while rotating the rotating shaft. In addition, the contaminated soil is excavated by the extraction solution injected from the nozzle at a high pressure, and at the same time, the contaminants contained in the contaminated soil are extracted. Therefore, it is not necessary to extract the contaminants.

Furthermore, in the above-mentioned soil purification method, when excavating contaminated soil, the contaminated soil is finely crushed and dispersed in the extraction solution, so that the contaminants contained in the contaminated soil can easily come into contact with the extraction solution. Therefore, the contaminants contained in the contaminated soil can be easily and reliably brought into contact with the extraction solution, and the contaminants contained in the contaminated soil can be extracted very effectively.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the purification status of contaminated soil,
It is the figure which showed the state which forms an excavation hole.

FIG. 2 is a schematic diagram showing the purification status of contaminated soil,
It is the figure which showed the state which excavates contaminated soil.

FIG. 3 is a schematic diagram showing the purification status of contaminated soil;
It is a figure showing the state where excavation of contaminated soil and backfilling in space are performed simultaneously.

FIGS. 1 to 5 are schematic diagrams showing a purification state of contaminated soil, and are diagrams showing a state in which backfilling in a space is performed.

FIGS. 1 to 5 are schematic diagrams showing a purification state of contaminated soil, and are diagrams showing a state in which backfilling in a space is completed.

FIG. 6 is a flowchart for explaining a process after discharging contaminated soil as cutting soil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contaminated soil 1a Upper end 1b Lower end 1c Cutting sand 3 Pump 4 Drilling hole 5 Space 6 Uncontaminated soil 10 Created body 20 Soil purification device 21 Drive unit 22 Drilling unit 22a Upper nozzle 22b Lower nozzle 22c Rotating shaft 23 Supply unit

Continuation of the front page F term (reference) 4D004 AA41 AB03 AB06 CA34 CA47 CB42 CB43 CB44 CC02 CC03 CC06

Claims (5)

[Claims] 1. A soil purification method for purifying contaminated soil located below an uncontaminated soil using a soil purification device, the method comprising: rotating a rotary shaft constituting an excavation part of the soil purification device; Forming a drilling hole having a depth at which the nozzle provided in the contaminated soil reaches the contaminated soil, by injecting an extraction solution and air having an extraction action and air from the nozzle at a high pressure while rotating the rotating shaft. Excavating the contaminated soil to form a space, and discharging the contaminated soil as cutting earth and sand through the drilling hole together with the extraction solution; and a liquid containing the cutting soil and the contaminant and the extraction solution. And a step of performing solid-liquid separation on purified soil; and a step of injecting the purified soil from the nozzle to backfill the space. 2. The nozzle comprises two sets of nozzles spaced from each other in the length direction of the rotating shaft, and one of the two sets of nozzles receives the extracted solution and air from one set of nozzles. 2. The soil purification according to claim 1, wherein the cleaning soil is injected from the other set of nozzles to backfill the space while the space is formed by injecting the purified soil at a high pressure. Method. 3. The soil purification method according to claim 1, wherein the extraction solution is an aqueous solution containing at least one selected from a chelating agent, an acid, an alkali, and a salt. 4. It has a rotating shaft and a nozzle provided on the rotating shaft, and it is possible to excavate locally by injecting an extraction solution and air at a high pressure from the nozzle while rotating the rotating shaft. A digging part capable of being locally backfilled by injecting soil from the nozzle while rotating the rotating shaft, a driving part for driving the digging part, and injecting from the nozzle A supply unit that supplies the extraction solution, the air, and the soil; a discharge unit configured to discharge the cut soil excavated in the excavation unit; and a solid-liquid separation unit configured to separate the cut soil into a liquid and purified soil. A soil purification device. 5. The nozzles are two sets of nozzles provided at intervals in the length direction of the rotating shaft, and one of the two sets of nozzles excavates. The soil purification apparatus according to claim 4, wherein the other set of nozzles performs backfilling.