JP4001798B2 - Purification method and apparatus for contaminated soil - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a purification treatment method and a purification treatment apparatus for regenerating soil contaminated with heavy metals and the like, and in particular, one or more kinds of chemicals (chemical purification) that are chemical countermeasures in situ in contaminated soil. Primary treatment to promote purification or insolubilization by stirring and mixing with chemicals and chemical insolubilizers), and mixing and mixing the contaminated soil after the primary treatment with cement-based or lime-based solidified materials in the same place The present invention relates to a contaminated soil purification treatment method and a purification treatment apparatus that are used in combination with a secondary treatment for containing contaminants.
[0002]
[Prior art]
As a purification treatment method for the regeneration of soil contaminated with heavy metals such as hexavalent chromium, it can be mixed with chemical purification agents or chemical insolubilizers so that heavy metals are not easily dissolved in water. Means have been taken such as limiting the influence, or containing contaminants contained in the soil by stirring and mixing with a cement-based or lime-based solidified material (see, for example, Patent Document 1). On the other hand, for the reason that long-term stability after insolubilization treatment of pollutants cannot be guaranteed, recently chemical insolubilization treatment etc. as a primary treatment and further containment treatment with cement-based solidifying material etc. as a secondary treatment There is a tendency to use both chemical purification treatment or insolubilization treatment and containment treatment.
[0003]
More specifically, as shown in FIGS. 8 and 9 , for example, two backhoes 101A and 101B, which are working construction machines, are used as base machines (base machines), and a stirring and mixing head 103 is attached to the tip of each arm 102. The chemical treatment or insolubilization process, which is the primary process, is performed in advance on one backhoe 101B, and then the secondary process is performed in the primary processed area so that the other backhoe 101A follows the preceding backhoe 101B. As a containment process. Reference numeral 104 denotes a chemical mixing plant for mixing a chemical cleaning agent or insolubilizing agent, which is a chemical countermeasure, as an aqueous solution, and 105 is also a solidifying material mixing plant for mixing, for example, a cement-based solidifying material as a slurry. . Further, as shown in FIG. 13, the stirring and mixing head 103 has a structure in which a plurality of stirring blades are provided on the outer periphery of a chain 106 that orbits in the vertical direction.
[0004]
[Patent Document 1]
JP 2002-206090 A (second page)
[0005]
[Problems to be solved by the invention]
However, if the contaminated soil that is the primary treatment and the chemical purifier or insolubilizer are mixed separately, and the mixed treatment that is the secondary treatment of the contaminated soil and the solidifying material are performed separately, Since the construction work is performed twice, the number of man-hours is large and uneconomical, and the facilities become large.In addition, the degree of agitation and mixing of contaminated soil, chemicals, and solidifying materials is likely to vary. It may not be fully achieved. In particular, if the variation in the degree of stirring and mixing deviates from the allowable range as a result of the follow-up investigation, reprocessing is unavoidable, which leads to an unnecessary increase in work man-hours.
[0006]
The present invention has been made paying attention to such a problem, and intends to provide a purification method and a purification treatment apparatus for contaminated soil, which can perform uniform stirring and mixing substantially once. Is.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, an endless chain that is driven to rotate in the vertical direction is wound between an upper drive wheel provided on the frame and a lower driven wheel provided on the frame, and the outer periphery of the chain is wound around the chain. Primary treatment for purification or insolubilization by stirring and mixing the soil contaminated with pollutants with one or more chemicals that are chemical countermeasures in situ by the stirring and mixing head equipped with multiple stirring blades In addition, the soil after the primary treatment is agitated and mixed with the solidified material at the same position, and the contaminated soil is treated as a secondary treatment, and the contaminated soil is purified. is moved by a predetermined distance in the longitudinal direction agitation mixing head mounted on the arm tip of the machine with a processing width of itself on that penetrates into the soil, contaminated soil and drugs Or Upon performing stirring and mixing with the solidifying material, the parts involved in the actual stirring and mixing process of the stirring mixing head, dividing partition its own processing width at least primary treatment area and the second process area by plate Dividing into multiple areas, the chemical treatment means from the primary treatment area of the agitation and mixing head, and the solidified material from the secondary treatment area are simultaneously discharged into the contaminated soil. Are performed in parallel, and the stirring and mixing process is repeatedly performed so that the processed areas are continuous with each other in the process width direction .
[0008]
That is, the stirring and mixing head is divided into two or more regions in the direction of its own processing width, and a part of these regions is divided into primary processing regions and the remaining regions are divided into secondary processing regions. If it is, it is enough. Moreover, the chemical | medical agent used as a chemical countermeasure at the time of a primary process is a chemical purification agent or a chemical insolubilizer, and you may use what mixed both as needed.
[0009]
In this case, as described in claim 2, after the stirring and mixing head penetrates into the ground to a predetermined depth, the stirring and mixing head is moved by a predetermined distance in the front-rear direction with its own processing width, and the stirring and mixing head is moved at the movement completion position. the operation on the raised back to penetrate position as one cycle, repeating the stirring and mixing treatment is desirable in the efficiency of construction.
[0010]
More specifically, as described in claim 3, the stirring and mixing head is divided into two in the processing width direction so that one region serves as a primary processing region and the other region serves as a secondary processing region, and the stirring is performed. In repeatedly performing the stirring and mixing process by the mixing head, it is desirable to perform the process so that the secondary processing area of the stirring and mixing head overlaps the processed area of the primary process before one cycle.
[0012]
In addition, as a more specific structure of the stirring and mixing head used for each stirring and mixing process, as described in claim 4, a drug discharge port connected to a drug pumping tube is provided in a primary processing region of the stirring and mixing head, The secondary treatment region has a solidified material discharge port connected to the solidified material pressure feed pipe, respectively, and among these chemical pressure feed tube and solidified material pressure feed tube, a compression directed to the respective pressure feed direction is provided in the vicinity of each discharge port. It is desirable that air is introduced in order to increase the uniformity of stirring and mixing with the contaminated soil by increasing the flow rate of the drug and the solidifying material and by the aeration effect.
[0013]
Therefore, in the inventions according to claims 1 to 3, particularly, as described in claims 2 and 3, the stirring and mixing head is divided into two, and one region is set as a primary processing region, and the other region is set as a secondary processing region. In such a case, the chemical mixing means and the contaminated soil are mixed and mixed as the primary treatment for purification or insolubilization of the contaminated soil in the half of the stirring and mixing head. In the remaining half of the area, the contaminated soil contained in the contaminated soil is contained by agitation and mixing of the contaminated soil and the solidified material after the primary treatment as the secondary treatment.
[0014]
【The invention's effect】
According to the first to third aspects of the present invention, the chemical purification or chemical insolubilization treatment that is the primary treatment and the physical containment treatment that is the secondary treatment are performed in parallel based on the movement of the single stirring and mixing head. As a result, it is possible to achieve the intended purpose with a single construction, which can dramatically improve the work efficiency in addition to simplifying the equipment, as well as the primary and secondary treatments. Is carried out continuously, there is an effect that the degree of agitation and mixing of the contaminated soil, the drug and the solidifying material is made uniform, and the variation can be eliminated.
[0015]
Also, the involved part of the actual stirring and mixing treatment of 撹拌mixing head, due to the structure that is divided into primary treatment area and the second processing region in the processing width direction with a splitting partition plate, existing For example There is an advantage that the intended purpose can be achieved simply by adding a dividing partition plate to the stirring and mixing head.
[0016]
According to the invention described in claim 4, since the compressed air is introduced immediately before the medicine and the solidifying material are discharged, the medicine and the solidifying material are discharged from the discharge port for acceleration by the compressed air. Is carried out stably and there is an advantage that the uniformity of stirring and mixing of the drug or solidifying material and the contaminated soil is further improved due to the so-called aeration effect.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 show a first preferred embodiment of the present invention. In particular, FIG. 1 is an overall plan view thereof, FIG. 2 is a left side view of the main part of FIG. 1, and FIGS. The details of the stirring and mixing heads 1 and 2 are shown respectively.
[0018]
As shown in FIG. 1, for example, a part of soil contaminated with heavy metal such as hexavalent chromium is partitioned as a purification (regeneration) target region Q, and a temporary steel plate 1 serving as a scaffold is adjacent to the region Q. It is laid.
[0019]
The purification processing apparatus for construction is configured with a backhoe 2 as a work system construction machine as a base machine (base machine), and a so-called trencher type stirring and mixing head 4 is mounted at the tip of the arm 3.
[0020]
As shown in FIGS. 3 and 4, the stirring and mixing head 4 is provided between a driving wheel 6 such as a chain sprocket provided on the upper part of a substantially prismatic frame 5 extending in the vertical direction and a driven wheel 7 provided on the lower part. An endless drive chain 8 is wound and a plurality of wide stirring blades 9 are mounted on the outer periphery of the drive chain 8 at a predetermined pitch. The drive wheel is driven by a hydraulic motor 10 provided on the same axis as the drive wheel 6. The agitating blades 9 are rotated together with the drive chain 8 by rotating the drive 6. A predetermined tension is applied to the drive chain 8 by a chain tensioner 11 provided on the frame 5 side.
[0021]
Also, the frame 5 is provided with a plurality of partition plates 12 so as to be symmetrical in FIGS. 3B and 4, and as shown in FIG. The width of the stirring blade 9 that is the processing width is equally divided into left and right with the partition plate 12. Thereby, the part which manages the actual stirring and mixing process in the stirring and mixing head 4 is divided into a left and right primary processing area F1 and a secondary processing area F2 with the partition plate 12 in FIG. 3A as the center.
[0022]
Furthermore, an independent drug discharge port 13 and solidifying material discharge port 14 are provided in the lower part of the frame 5 for each of the primary processing region F1 and the secondary processing region F2. The drug discharge port 13 is connected to the drug mixing plant 16 of FIG. 1 via a drug pressure feeding tube 15, and the solidification material discharge port 14 is connected to the solidification material mixing plant 18 of FIG. ing. The prismatic frame 5 has a sealed inner space that also serves as an air tank, and compressed air is introduced from a pressure source (not shown) through an air pipe 20 connected to a port 19 at the top of the frame 5. ing. Further, the air pipe 22 connected to the port 21 at the lower part of the frame 5 is located at the ends of the drug pressure feed pipe 15 and the solidifying material pressure feed pipe 17, that is, slightly upstream of the drug discharge port 13 and the solidification material discharge port 14, respectively. The compressed air in the frame 5 is introduced into the drug pressure feeding pipe 15 and the solidified material pressure feeding pipe 17 so as to be connected and directed in the pressure feeding direction or the discharge direction.
[0023]
The drug mixing plant 16 and the solidifying material mixing plant 18 shown in FIG. 1 basically have the same configuration, and are a silo 23, a water tank 24, a mixer 25, a grout pump 26, a generator 27, a flow meter 28, and the like. It has. In the chemical mixing plant 16, a chemical purifying agent or chemical insolubilizer and water are mixed to form an aqueous solution and pumped to the stirring and mixing head 4 side. On the stirring and mixing head 4 side, FIG. As shown in FIG. 5, the medicine is ejected from the medicine ejection port 13 in a diffusion state downward, for example, under the ejection pattern P1. In the chemical mixing plant 16, a chemical purifying agent or a chemical insolubilizing agent may be used alone and then mixed with water to form an aqueous solution. However, if necessary, the chemical purifying agent and the chemical insolubilizing agent are used in combination. It may be mixed with water to form an aqueous solution. Similarly, in the solidifying material mixing plant 18, a cement-based solidifying material or lime-based solidifying material and water are mixed to form a slurry-like aqueous solution and then pumped to the stirring and mixing head 4 side, while the solidifying material mixing plant 18 is solidified. For example, the material is discharged in a diffused state downward from the material discharge port 14 under the discharge pattern P2.
[0024]
Here, as described above, the compressed air is introduced so as to be directed in the discharge direction immediately before the predetermined drug or solidification material is discharged from the drug discharge port 13 and the solidification material discharge port 14. The medicine or solidifying material immediately before the discharge is further accelerated.
[0025]
In the contaminated soil purification equipment configured as described above, each stirring blade 9 of the stirring and mixing head 4 is moved around together with the drive chain 8 as shown in FIGS. In a state where the chemical insolubilizer is simultaneously discharged from the solidifying material discharge port 14, the stirring and mixing head 4 itself is placed in the contaminated soil in a vertical posture along the virtual partition line a 1 of the purification target region Q. After penetrating to a predetermined depth, the width of the stirring blade 9 is set as the processing width while maintaining the penetration depth, and the reach of the back hoe 2 is used to move in the front-rear direction to the other virtual marking line a2, and at the movement completion position After the stirring and mixing head 4 is pulled up, the operation of returning to the penetration position again is set as one cycle, and the backhoe 2 itself is intermittently traversed, and the construction is carried out once, and further, the process is performed once. (F1 + F2) processed region of assumed repeating construction continuously to continuously together with the processing width direction.
[0026]
In this case, in the portion corresponding to the primary processing region F1 of the stirring and mixing head 4, the chemical purifier or chemical insolubilizer discharged as the primary processing and the contaminated soil are stirred and mixed, while the secondary of the stirring and mixing head 4 is mixed. In the portion corresponding to the processing region F2, the solidified material discharged as the secondary processing and the contaminated soil are mixed with stirring. In this stirring and mixing process, since the compressed air is mixed immediately before the medicine or the solidified material discharged from the medicine discharge port 13 and the solidifying material discharge port 14, the drug or the solidified material is used for the so-called aeration effect. Uniformity of stirring and mixing of the solidified material and the contaminated soil will be improved.
[0027]
That is, as shown in FIG. 1, the chemical purifier or chemical insolubilizer and the contaminated soil are stirred and mixed in the treated region for each cycle in which the width (F1 + F2) of the stirring blade 9 is the treatment width. Since the primary treatment area and the secondary treatment area where the solidified material and the contaminated soil are mixed with stirring are arranged side by side, the n-th treatment area and the n + 1-th treatment area in the process of continuous construction. It is assumed that the processing is performed so that the processed region overlaps each other by a half of the processing width dimension (F1 + F2). By doing so, in the construction process of one cycle by the stirring and mixing head 4, the secondary treatment for the primary treated region (the region where the stirring and mixing treatment of the chemical purifying agent or chemical insolubilizer and the contaminated soil has already been completed) is performed. Treatment (stirred mixing treatment of contaminated soil and solidified material that has already undergone primary treatment) and primary treatment in a region adjacent to it (stirring mixing treatment of chemical purifier or chemical insolubilizer and contaminated soil) Will be performed in parallel in the form of simultaneous progress.
[0028]
For example, in the example of FIG. 1, the area b is an area where both the primary process and the secondary process have already been completed, and the areas b1 and b2 are the areas currently being constructed, but the area b1 has already been completed with the primary process. In addition, the secondary process is an area in which the primary process is currently in progress, and the area b2 is an area in which the primary process is currently in progress.
[0029]
As described above, according to the present embodiment, the primary treatment and the secondary treatment are performed in parallel in the process of performing the construction substantially once by the single stirring and mixing head 4 having the backhoe 2 as a base. In addition, the primary treatment and the secondary treatment are continuously performed, so that the work efficiency can be improved and the degree of stirring and mixing can be made uniform.
[0030]
Here, as a quality evaluation system after the purification treatment of the contaminated soil, the discharge amount of the chemical or the solidifying material for chemical purification or chemical insolubilization, the rotation speed and processing speed of the drive unit in the stirring and mixing head 4, and the contamination soil It is desirable that the improvement depth (depth of penetration of the stirring and mixing head 4) and the like are measured and recorded in real time or periodically so that it can always be confirmed whether or not the actual purification processing quality satisfies the target processing quality.
[0031]
5 to 7 show another example of the stirring and mixing head according to the second embodiment of the present invention.
[0032]
In the second embodiment, two drive chains 37 having stirring blades 36 on the outer periphery are provided on a common frame 35 of the stirring and mixing head 34, respectively, and an upper drive wheel 38 and a lower driven wheel. 39 are arranged in parallel so as to be wound around the drive shaft 37, and simultaneously driven by a single hydraulic motor 40 sharing the two drive chains 37. The frame 35 is provided with a partition plate 41, whereby one drive chain 37 side is partitioned as a primary processing region F1, and the other drive chain 37 side is partitioned as a secondary processing region F2. A pair of left and right drug discharge ports 43 branched from the drug pressure feeding tube 42 are provided on the F1 side, and a pair of left and right solidification material discharge ports 45 similarly branched from the solidification material pressure feeding tube 44 are provided on the secondary processing region F2 side. ing. Similarly to the first embodiment, the frame 35 also serves as an air tank, and the compressed air once introduced into the frame 35 via the air pipe 20 is also connected to the medicine discharge port via the air pipe 22. 43 and the solidified material discharge port 45 are supplied to the upstream side. Each drive chain 37 is individually given a predetermined tension by a chain tensioner 46.
[0033]
According to the second embodiment, the processing width dimension in the stirring and mixing head 34 (the width dimension of the stirring blade 36 as a whole of the stirring and mixing head 34) and the processing width dimension in the primary processing region F1 and the secondary processing region F2 are as follows. Since (the width dimension of the stirring blade 36 for each drive chain 37) can be secured larger than that of the first embodiment, there is an advantage that the processing efficiency is further improved.
[0039]
Assuming that a chemical purification agent and a chemical insolubilizer are used in addition to the solidifying material , the stirring and mixing head is divided into three equal parts in the direction of its own treatment width by two partition plates, and chemical purification is performed. Mixing of the solidified material with the contaminated soil after the primary and secondary treatments, with the mixing of the chemical and the contaminated soil as the primary treatment, and the mixing of the chemical insolubilizer with the contaminated soil after the primary treatment as the secondary treatment was assumed to be performed in parallel each processing as tertiary treatment, secondary treatment area of stirring and mixing heads side to the primary processed area in the processing target area Q of the contaminated soil per cycle operation is overlapped and two it is also possible to tertiary treatment area for the next processed area to a stirred mixture Head side performs construction by moving the stirring mixture heads so as to overlap.
[Brief description of the drawings]
FIG. 1 is an explanatory plan view showing a first embodiment of a contaminated soil purification system according to the present invention.
FIG. 2 is a left side view of the main part of FIG.
FIGS. 3A and 3B are diagrams showing details of the stirring and mixing head shown in FIGS. 1 and 2, wherein FIG. 3A is a front view thereof, and FIG. 3B is a left side view of FIG.
4 is a right side view of FIG.
FIG. 5 is a front view showing another type of agitation head according to a second embodiment of the present invention.
6 is a left side view of FIG.
7 is a right side view of FIG.
FIG. 8 is an explanatory plan view showing an example of a conventional contaminated soil purification system.
FIG. 9 is a left side view of a main part of Figure 8.
[Explanation of symbols]
2 ... Backhoe (working construction machine)
DESCRIPTION OF SYMBOLS 3 ... Arm 4 ... Agitation mixing head 5 ... Frame 6 ... Drive wheel 7 ... Driven wheel 8 ... Drive chain 9 ... Agitation blade 12 ... Partition plate 13 ... Drug discharge port 14 ... Solidification material discharge port 15 ... Drug pressure feed tube 17 ... Solidification Material pressure feed pipe 20, 22 ... Air pipe 34 ... Stirring mixing head 35 ... Frame 36 ... Stirring blade 37 ... Drive chain 38 ... Drive wheel 39 ... Driven wheel 41 ... Partition plate 42 ... Drug pressure feed pipe 43 ... Drug discharge port 44 ... Solidification Material feed pipe 45 ... Solidified material discharge port
F1 ... Primary processing area F2 ... Secondary processing area

Claims (4)

An endless chain that is driven in a vertical direction is wound between the upper drive wheel provided on the frame and the lower driven wheel provided on the frame, and agitation mixing is performed by attaching a plurality of agitation blades to the outer periphery of the chain. The head is subjected to primary treatment for purification or insolubilization by stirring and mixing the soil contaminated with pollutants in situ with one or more chemicals as chemical countermeasures, and after the primary treatment A method for purifying contaminated soil in which a contaminant is contained as a secondary treatment by stirring and mixing with a solidifying material in the same place,
After agitating and mixing head attached to the tip of the arm of the work system construction machine penetrates into the soil , it is moved by a predetermined distance in the front-rear direction with its own treatment width to agitate and mix the contaminated soil and the drug or solidifying material. In giving
The part involved in the actual stirring and mixing process of the stirring and mixing head is divided into a plurality of regions of at least a primary processing region and a secondary processing region in the processing width direction of itself by a dividing partition plate ,
From the primary treatment area of the stirring and mixing head, the chemical countermeasure means, and from the secondary treatment area, the solidified material is simultaneously discharged into the contaminated soil, and the primary treatment and the secondary treatment are performed in parallel .
A method for purifying contaminated soil, characterized in that the agitation and mixing treatment is repeatedly performed so that the treated regions are continuous in the treatment width direction . One cycle of the stirring and mixing head penetrating into the ground up to a predetermined depth, moving it by a predetermined distance in the front-rear direction with its own processing width , raising the stirring and mixing head at the movement completion position, and returning it to the penetration position and to, purification treatment method contaminated soil according to claim 1, characterized in that repeating the stirring and mixing process. The stirring and mixing head is divided into two in the processing width direction, and one region is a primary processing region and the other region is a secondary processing region,
When repeatedly performing the stirring and mixing process by the stirring and mixing head, the secondary processing region of the stirring and mixing head is overlapped with the processed region of the primary process before one cycle. The method for purifying contaminated soil according to claim 2. It is an apparatus used for the purification processing method of the contaminated soil of Claim 1, Comprising:
In the primary processing area of the agitation and mixing head, the medicine discharge port connected to the drug pressure feeding pipe is faced, and in the secondary processing area, the solidification material discharge port connected to the solidification material pressure feeding pipe is faced.
Purifying apparatus of contaminated soil you characterized in that compressed air is adapted to be introduced in the vicinity of each discharge port for directing each of the pumping direction of the drug pumping tube and the solidifying material pumping pipe.

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