JP3982245B2 - Purification method of contaminated soil by microorganisms - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for purifying contaminated soil by microorganisms, and more particularly, to a method for microbial purification of contaminated soil contaminated with organic substances such as oil and organic chlorine compounds.
[0002]
[Prior art]
Recently, when a factory site is redeveloped, for example, when trying to reuse it for residential land, the soil of the site may be contaminated with organic substances such as oil and organic chlorine compounds. In the case where there is such soil contamination, the reuse of the contaminated soil is hindered.
[0003]
FIG. 4 shows an example of a contaminated soil purification method conventionally employed. The purification method shown in the figure shows the purification of the original contaminated soil S0 containing oil. 1. Excavation and transportation process 2. Selection process of gravel and contaminated soil S1 A step of mixing the improved material into the contaminated soil S1 and mixing them to produce the contaminated mixed soil S2, and 4,5. 5. transporting the contaminated mixed soil S2 to the bioyard and performing natural purification promotion work in the bioyard; And a step of backfilling the purification treated soil S3 to the original place.
[0004]
In the excavation and transport process, the raw contaminated soil S0 found by the survey is excavated by the backhoe 1 and transported to a predetermined place by the dump truck 2. In the sorting step, the contaminated soil S1 lowered from the dump truck 2 is supplied to the sorter 4 by the power shovel 3, and is separated into gravel and contaminated soil S1 by the sieve type sorter 4, and the gravel is removed.
[0005]
The contaminated soil S1 from which the gravel has been removed is transported to the material mixing yard, where the power shovel 3 spreads out and spreads out the improved materials such as sawdust and fertilizer, and these are kneaded by the cultivator 6. Thus, the contaminated mixed soil S2 is produced.
[0006]
The contaminated mixed soil S2 is transported to the bioyard by the dump truck 2, where natural purification promotion work is performed. In this operation, sprinkling by the sprinkler 6 and agitation of the backhoe 1 are performed at predetermined intervals, and the oil is decomposed by the power of microorganisms originally contained in the soil, so that the purification treated soil S3 is produced. The prepared purification soil S3 is then backfilled to the original location.
[0007]
However, such conventional purification methods have the following technical problems.
[0008]
[Problems to be solved by the invention]
That is, in the conventional purification method shown in FIG. 4, the sieving separator 4 separates the gravel from the contaminated soil S1, removes the gravel, and then mixes the improved material. As a result, a large work area is required, and when these operations are performed individually, the work takes time and the purification treatment period is prolonged.
[0009]
The present invention has been made in view of such conventional problems, and the object of the present invention is to reduce the required work area and shorten the purification treatment period. It is providing the purification method of the contaminated soil by the microorganisms.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention mixes an improved material such as sawdust and fertilizer into contaminated soil mixed with organic substances such as oil and organic chlorine compounds, and the organic matter is introduced by microorganisms in the soil. In the method for purifying contaminated soil, which decomposes and removes substances, a step of excavating the contaminated soil and transporting it to a material mixing yard, and measuring the degree of contamination of the contaminated soil during the transportation, and treating microorganisms In the material mixing yard, the improved material is supplied to the contaminated soil, the gravel in the contaminated soil is removed, and the contaminated soil and the improved material are mixed. A step of producing a contaminated mixed soil, a step of classifying the contaminated mixed soil into a plurality of concentrations according to the degree of contamination, and a contamination classified in the bioyard after transporting the contaminated mixed soil to the bioyard. and curing every mixed soil, regular A process of preparing a treated soil by decomposing the organic substance by microorganisms in the ground, and a step of refilling the treated soil Preparation , mixing of the contaminated soil and the improved material in the step of preparing the contaminated mixed soil, stirring, classification work of the gravel and contaminated soil, and oxygen replenishment operation in the step of preparing the treated soil to, and to use the screen bucket.
[0011]
According to the purification method of contaminated soil by microorganisms thus configured, after supplying the improved soil to the contaminated soil, the contaminated soil and the improved material are mixed to remove the contaminated mixed soil while removing the gravel in the contaminated soil. Because it is manufactured, separate locations are not required for gravel sorting and material mixing, and purification processing can be performed with a small work area, and by simultaneously performing gravel sorting and material mixing, work time can be shortened. I can plan.
[0013]
According to the present invention, before the step of producing the purification treated soil, the contaminated mixed soil is classified into a plurality according to the degree of contamination, and when the soil is cured in the bioyard, each classified mixed soil is classified. Since curing is performed, the interval between oxygen supplementation and water supplementation can be set according to the degree of contamination, and curing management can be performed easily and appropriately.
[0015]
In addition, the present invention mixes improved materials such as sawdust and fertilizer into contaminated soil mixed with organic substances such as oil and organic chlorine compounds, and decomposes and removes the organic substances by soil microorganisms. In the method for purifying contaminated soil, a step of excavating the contaminated soil and transporting it to a material mixing yard, and measuring the degree of contamination of the contaminated soil during the transportation, it is determined that microbial treatment is possible Then, in the material mixing yard, the improved material is supplied to the contaminated soil, and the contaminated soil and the improved material are mixed and mixed while being crushed without removing gravel in the contaminated soil. A step of preparing soil, a step of classifying the contaminated mixed soil into a plurality of concentrations according to the degree of contamination, and after transporting the contaminated mixed soil to a bioyard, the contaminated mixed soil classified in the bioyard and cured in each, regular acid Perform the hydration by replenishment with water spray, and a period of time curing, comprising the steps of preparing a purification treatment soil by decomposing the organic substance with underground microorganisms, and a step of backfilling said purification treated soil, In the step of preparing the contaminated mixed soil, the mixing of the contaminated soil and the improved material, stirring and crushing of the gravel, and the oxygen supply operation in the step of preparing the purification treated soil, for soft rock excavation A twin header was used .
[0016]
According to the method for purifying contaminated soil by microorganisms configured in this way, after supplying the improved material to the contaminated soil in the material mixing yard, the contaminated soil and the improved material are crushed without removing the gravel in the contaminated soil. To create contaminated mixed soil, so there is no need for separate locations for gravel sorting and material mixing, purification can be done in a small work area, and gravel crushing and material mixing are performed simultaneously. As a result, the working time can be shortened.
[0018]
According to the present invention, before the step of producing the purification treated soil, the contaminated mixed soil is classified into a plurality according to the degree of contamination, and when the soil is cured in the bioyard, each classified mixed soil is classified. Since curing is performed, the interval between oxygen supplementation and water supplementation can be set according to the degree of contamination, and curing management can be performed easily and appropriately.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of the method for purifying contaminated soil by microorganisms according to the present invention.
[0021]
In the purification method shown in the figure, the raw material contaminated soil A0 mixed with oil as an organic substance is mixed with improved material B such as sawdust and fertilizer, and the oil is decomposed and removed by microorganisms in the soil. Is the basic configuration. The organic substance to be purified by microorganisms is not limited to oil, and may be, for example, an organic chlorine compound.
[0022]
In the purification method of the present embodiment, as shown in FIG. 1, when the purification processing procedure is started, first, in step 1, as in the conventional method of this type, the original contaminated soil A0 that has been found by the investigation is back-hauled or the like. Excavate and transport to a material mixing yard with a dump truck.
[0023]
At the time of transportation, in step 2, the degree of contamination of the oil of the original contaminated soil A0 is measured, and it is determined whether or not purification by microbial treatment is possible. If it is determined in step 2 that the degree of contamination cannot be purified, another purification method is performed in step 3. In this case, the measurement of the degree of contamination of oil may be performed every predetermined m ³ in accordance with the degree of contamination that has been found in a survey conducted in advance.
[0024]
In step 2, the original contaminated soil A0 determined to be capable of being purified is transported to the material mixing yard, where the improved material B is supplied and then kneaded to prepare the contaminated mixed soil A1. Produced (step 4).
[0025]
In the case of the present embodiment, the screen bucket 10 shown in FIG. 2 is used for spreading and kneading in this case. The screen bucket 10 shown in the figure has a structure that can be attached to the tip of a hydraulic heavy machine such as a backhoe, and has a function of performing mixing, stirring, and classification at the same time. 10a and a bottom plate 10c having both ends fixed to the lower portions of the side plates 10a and 10a, and an opening 10d is provided on the back side.
[0026]
A cover 10f having a rotation drive shaft 10e provided therein is provided on the upper side of the side plates 10a and 10a. Further, between the opposing side plates 10a, 10a, a predetermined interval is provided in the vertical direction, and four stirring shafts 10g are rotatably supported.
[0027]
Each stirring shaft 10g has a plurality of stirring blades 10h protruding from the outer peripheral surface. The stirring blades 10h are disposed at a predetermined interval along the longitudinal axis direction of the stirring shaft 10g and at equal angular intervals along the circumferential direction. When the rotary drive shaft 10e is rotated by the hydraulic pressure supplied from the heavy machinery side, the stirring shaft 10g rotates in a predetermined direction.
[0028]
According to the screen bucket 10 configured in this manner, when the stirring shaft 10g is rotated while scooping up and swinging the original contaminated soil A0 in the material mixing yard, the gravel contained in the original contaminated soil A0 is stirred. The passage of the shaft 10g or the stirring blade 10h is prevented from passing and remains in the bucket 10 so that the gravel can be removed (classified).
[0029]
On the other hand, the earth and sand particles of the raw contaminated soil A0 not containing gravel pass through the setting interval portion of the stirring shaft 10g or the stirring blade 10h, pass through the opening 10d, accumulate on the material mixing yard, and are spread and leveled. .
[0030]
In this case, since the raw contaminated soil A0 scooped up in the bucket 10 is stirred as the stirring shaft 10g rotates, if the improved material B is supplied in advance, the raw contaminated soil A0 from which the gravel has been removed Mixing and stirring with the improved material B can be performed simultaneously.
[0031]
Further, when the contaminated soil is contained in the original contaminated soil A0, it can be finely crushed by the stirring blade 10h of the screen bucket 10 and crushed. Can be mixed. Further, the screen Baketsuto 10 of the present embodiment, since used as hydraulic and body heavy equipment with such existing backhoe, is advantageous in economical viewpoint.
[0032]
Thus, when producing contaminated mixed soil A1, the improvement material B mixed with sandy soil and viscous soil can be properly used. The improvement material B can use compost, inorganic fertilizers such as nitrogen and phosphoric acid, and sawdust.
[0033]
When the raw contaminated mixed soil A0 is sandy soil, inorganic fertilizer is suitable, and when it is viscous soil, okagus can be suitably used. Next, in step 5, classification of the produced contaminated mixed soil A1 is performed according to concentration.
[0034]
This classification by concentration is performed when the contaminated mixed soil A1 is classified into a plurality of, for example, about five levels according to the degree of contamination and cured in the bioyard before the process of preparing the purification treated soil A2 described later. Cured for each contaminated mixed soil.
[0035]
When such concentration classification is performed , the interval between oxygen supply and water supply can be set according to the degree of contamination, and curing management can be performed easily and appropriately.
[0036]
In the subsequent step 6, the contaminated mixed soil A1 is transported to the bioyard by a dump truck or the like, and the purification treated soil A2 is produced in the bioyard. The purification soil A2 is produced in a bioyard with regular oxygen supplementation and water replenishment by watering, curing for a certain period of time (for example, about 3 months to half a year), and oil (organic) by microorganisms in the ground. To be produced by decomposing the active substance).
[0037]
The microorganism used at this time is an indigenous microorganism, and actively propagates microorganisms originally present in the earth and sand.
[0038]
In order to increase the activity of such microorganisms, oxygen supplementation and water supplementation are periodically performed at a frequency of about two to three times a week. In this case, oxygen supplementation is shown in FIG. The screen bucket 10 is attached to a hydraulic heavy machine such as a backhoe, the contaminated mixed soil A1 is scooped up, stirred and mixed, and aerated. In this case, the clay can be crushed together.
[0039]
When the purification soil A2 is produced by the above processing, the purification soil A2 is subjected to final confirmation of the degree of contamination in the subsequent step 7, and if it passes, it is transported by a dump truck or the like to the original location. After that, if necessary, spreading and rolling are performed, and purification is completed (step 8).
[0040]
Now, according to the purification method configured as described above, after supplying the improved material B to the original contaminated soil A0, the original contaminated soil A0 and the improved material B are mixed while removing the gravel in the original contaminated soil A0. Since the contaminated mixed soil A1 is produced, separate locations are not required for gravel sorting and material mixing, purification can be performed in a small work area, and gravel sorting and material mixing are performed simultaneously. The working time can be shortened.
[0041]
FIG. 3 shows a twin header for soft rock excavation used in another embodiment of the purification treatment method according to the present invention. The twin header 12 shown in the figure is attached to a heavy machine by hydraulic pressure such as a backhoe similarly to the screen bucket 10 described above.
[0042]
The twin header 12 includes a mounting bracket 12a, a pair of hydraulically driven rotating drums 12b, and a plurality of excavation bits 12c projecting from the outer periphery of the rotating drum 12b.
[0043]
In the twin header 12 configured as described above, by rotating the rotary drum 12b, the excavation bit 12c can crush the gravel and can also crush the clay.
[0044]
In the purification method using such a twin header 12, as in the above-described embodiment, the improved material B such as sawdust and fertilizer is mixed in the raw contaminated soil A0 mixed with organic substances such as oil and organic chlorine compounds. The basic structure is to decompose and remove organic substances by microorganisms in the soil.
[0045]
The specific processing procedure is almost the same as the procedure shown in FIG. 1, and the process of excavating the original contaminated soil A0 and transporting it to the material mixing yard (step 1) and investigating the degree of contamination are performed. A step (Step 2) for determining whether or not it is possible, a step (Step 3) for producing the contaminated mixed soil A1 by mixing the original contaminated soil A0 and the improved material B in the material mixing yard, and Depending on the concentration classification process (step 5) of contaminated mixed soil A1 adopted according to the situation, after transporting the contaminated mixed soil A1 to the bioyard, regular oxygen supplementation and water replenishment by watering are carried out for a certain period of time. Then, a process of producing organic soil A2 by decomposing organic substances by underground microorganisms (step 6), and a step of refilling the soil after confirming the degree of contamination of the environmental soil A2 (steps 7 and 8). ).
[0046]
In such a processing procedure, in the case of the present embodiment, the twin header 12 is used in place of the screen bucket 10 of the above embodiment in steps 4 and 6.
[0047]
That is, since the twin header 12 can crush gravel, if this is adopted in the step of mixing the raw contaminated soil A0 and the improved material B performed in step 4 to produce the contaminated mixed soil A1, the original contaminated soil A0. The contaminated mixed soil A1 can be produced while crushing without removing the gravel inside.
[0048]
In addition, when the twin header 12 is used in the oxygen replenishment work in the process of preparing the purification treated soil A2 in Step 6, the contaminated mixed soil A1 is stirred and mixed, aerated, and the clay is also crushed. Can do.
[0049]
In the embodiment configured as described above, the same effects as those in the above embodiment can be obtained.
[0050]
【The invention's effect】
As described above in detail, according to the method for purifying contaminated soil by microorganisms according to the present invention, the required work area can be reduced and the purification treatment period can be shortened.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a processing procedure of an embodiment of a method for purifying contaminated soil by microorganisms according to the present invention.
FIGS. 2A and 2B are a front view and a side view of a screen bucket used in the embodiment shown in FIG.
FIG. 3 is a top view and a side view of a twin header used in another embodiment of the method for purifying contaminated soil by microorganisms according to the present invention.
FIG. 4 is a process explanatory diagram of a conventional method for purifying contaminated soil.
[Explanation of symbols]
A0 Original contaminated soil A1 Contaminated mixed soil A2 Purification soil B Improved material 10 Screen bucket 12 Twin header

Claims (2)

A method for purifying contaminated soil in which contaminated soil mixed with organic substances such as oil and organic chlorine compounds is mixed with improved materials such as sawdust and fertilizer, and the organic substances are decomposed and removed by microorganisms in the soil. In
Excavating the contaminated soil and transporting it to a material mixing yard;
During the transportation, after measuring the degree of contamination of the contaminated soil and determining that microbial treatment is possible, the improved material is supplied to the contaminated soil in the material mixing yard, A step of mixing the contaminated soil and the improved material to produce a contaminated mixed soil while removing gravel of
A step of classifying the contaminated mixed soil into a plurality of concentrations according to the degree of contamination;
After transporting the contaminated mixed soil to the bioyard, the bioyard is cured for each classified contaminated mixed soil, regularly replenished with oxygen and watered by watering, and cured for a certain period of time. A step of decomposing the organic substance by microorganisms to produce a purified soil;
And refilling the purification treated soil ,
In the step of preparing the contaminated mixed soil, the mixing of the contaminated soil and the improved material, stirring and classification work of the gravel and the contaminated soil, and the oxygen supply operation in the step of preparing the purification treated soil, A method for purifying contaminated soil by microorganisms, characterized by using a screen bucket . A method for purifying contaminated soil in which contaminated soil mixed with organic substances such as oil and organic chlorine compounds is mixed with improved materials such as sawdust and fertilizer, and the organic substances are decomposed and removed by microorganisms in the soil. In
  Excavating the contaminated soil and transporting it to a material mixing yard;
  During the transportation, after measuring the degree of contamination of the contaminated soil and determining that microbial treatment is possible, in the material mixing yard, supplying the improved material to the contaminated soil, Crushing without removing the gravel, mixing the contaminated soil and the improved material to produce a contaminated mixed soil,
  A step of classifying the contaminated mixed soil into a plurality of concentrations according to the degree of contamination;
  After transporting the contaminated mixed soil to the bioyard, the bioyard is cured for each classified contaminated mixed soil, periodically replenished with oxygen and watered by watering, and cured for a certain period of time. A step of decomposing the organic substance by microorganisms to produce a purified soil;
  And refilling the purification treated soil,
  In the step of producing the contaminated mixed soil, the mixing of the contaminated soil and the improved material, stirring and crushing of the gravel, and the oxygen supply operation in the step of producing the purified treated soil are for soft rock excavation. A method for purifying contaminated soil by microorganisms, characterized by using a twin header.

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