JP3776378B2 - Contaminated soil treatment system and contaminated soil treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a purification treatment of soil contaminated with lead, and more particularly to a contaminated soil treatment system and a contaminated soil treatment method that can reliably purify contaminated soil containing lead ammunition as a contamination source.
[0002]
[Prior art]
The site of various factories may contain heavy metal substances such as hexavalent chromium and cadmium. These heavy metal substances such as hexavalent chromium and cadmium are designated as soil pollutants in the environmental standards related to soil contamination (Environmental Agency Notification No. 46). When the amount of elution exceeds the value specified in the environmental standards, it is determined as contaminated soil. A so-called insolubilization process is generally used as a method for treating soil contaminated with such heavy metal substances. This insolubilization treatment suppresses elution of heavy metals by adding a chemical (insolubilizing agent) according to the type of heavy metal to the contaminated soil and changing the heavy metal into a hardly soluble compound.
[0003]
As a method for insolubilizing such contaminated soil, for example, a contaminated soil treatment apparatus described in JP-A-9-253620 has already been proposed. This contaminated soil treatment device mixes contaminated soil, chemicals (insolubilizer), water, and cement in a mixing device (mixer), and pollutants in the contaminated soil are hardly soluble by chemicals. (Solubilized) and chemically stabilized by hardening with cement. Usually, the denatured soil thus detoxified is used as backfill soil, or is transported to a final disposal site or the like for landfill disposal.
[0004]
[Problems to be solved by the invention]
Here, research has recently revealed that lead, which is a harmful pollutant, has melted from lead bombs scattered on the surface of the ground at a shooting range, etc., and may cause contamination of the surrounding soil. It is a problem.
[0005]
When contaminated soil containing lead ammunition, which is the source of such contamination, is treated, the conventional technology described above is simply configured to mix excavated contaminated soil together with chemicals, cement, etc. The bullet will remain. That is, even if the pollutant (lead) in the contaminated soil is insolubilized, the contamination source remains in the treated soil. For this reason, if this treated soil is backfilled as it is, lead will eventually be eluted from the remaining lead bullets and will be contaminated again, and this will not be a fundamental purification measure. For this reason, the above-described conventional technology cannot be applied when contaminated soil mixed with lead ammunition as a contamination source is treated.
[0006]
The present invention has been made on the basis of the above matters, and the purpose thereof is a contaminated soil treatment system and a contaminated soil that can reliably purify even contaminated soil mixed with lead ammunition as a contamination source. It is to provide a processing method.
[0007]
[Means for Solving the Problems]
(1) In order to achieve the above object, the contaminated soil treatment system of the present invention supplies and mixes an insolubilizer that insolubilizes lead and water into contaminated soil mixed with lead ammunition, which is a pollution source, and insolubilizes it. Self-propelled insolubilization processing machine that generates soil, and self-propelled type that generates modified soil by supplying and mixing exothermic additive to the insolubilized soil generated by this self-propelled insolubilization processing machine A reforming processing machine; and a sorting machine that classifies the modified earth generated by the self-propelled reforming processing machine and separates the lead bullets from the modified earth.
[0008]
Usually, lead bullets sometimes contain shots and the like, and there are many small particles having a particle diameter of about 2 to 4 mm. When separating such a small lead bullet from contaminated soil, it is conceivable to use a sieve device. However, since the lead bullets to be selected have a small particle size, it is necessary to use a fine sieve. In this case, even if the contaminated soil is passed through a sieve, the viscous soil contained in the contaminated soil adheres to the eyes of the sieve and causes clogging. In practice, it is difficult to separate the lead bullets.
[0009]
Therefore, in the present invention, first, the contaminated soil is insolubilized in a state containing lead bullets, and this insolubilized soil is mixed with an additive to form a modified soil and classified. As the additive, for example, lime (or lime-based solidifying material) or the like that generates heat by reacting with moisture in the soil, or powder of iron (or iron oxide, aluminum, etc.) is used. By reducing the water content of the insolubilized soil by evaporating moisture, it is possible to produce modified soil with low plasticity. Moreover, when lime (or lime-based solidification material) is added, the particles of the insolubilized soil are aggregated by an ion exchange reaction, and modified soil that is easier to handle in the subsequent classification step can be generated.
[0010]
Thereby, the modified earth is not easily attached to the eyes of the sieve member of the sorting machine, and the soil is easily separated from each other, and the lead ammunition can be separated from the modified earth. Therefore, it is possible to insolubilize lead in contaminated soil and remove the lead bullets that are the source of contamination to prevent future contamination. Can be purified. Another advantage is that lead bullets can be removed by dry classification.
[0011]
(2) In order to achieve the above object, the contaminated soil treatment system of the present invention supplies and mixes an insolubilizer for insolubilizing lead and water into the contaminated soil mixed with lead ammunition, which is the source of contamination, and insolubilizes it. Contamination equipped with an insolubilization treatment device for producing treated soil, and a reforming treatment device for producing an improved soil by supplying and mixing an additive having an exothermic action to the insolubilized treatment soil produced by the insolubilization treatment device A soil treatment machine; and a sorting machine that classifies the modified soil generated by the contaminated soil treatment machine and separates the lead bullets from the modified soil.
[0012]
(3) In order to achieve the above-mentioned object, the present invention supplies an insolubilizing agent for insolubilizing lead and water to the contaminated soil mixed with lead ammunition, which is a contamination source, and mixes them to produce an insolubilized treated soil. A self-propelled insolubilizing machine, a sorting machine for classifying the insolubilized soil generated by the self-propelled insolubilizing machine, and separating the lead bullets from the insolubilized treated soil, and removing the lead bullets with the sorting machine A self-propelled reforming processing machine that supplies and mixes an additive having a solidifying action to the insolubilized treated soil to generate modified soil is provided.
[0013]
In the present invention, first, contaminated soil is insolubilized in a state containing lead bullets, and the insolubilized treated soil is supplied to a sorting machine to separate lead bullets. In the self-propelled insolubilizing machine, water is supplied together with the insolubilizing agent to the contaminated soil so that the insolubilizing agent is uniformly mixed. That is, the insolubilized soil discharged from the self-propelled insolubilizing machine is in a slurry state with a very high water content at this point, so it easily passes through the sieve member of the sorting machine and easily separates lead bullets. can do. Then, the insolubilized soil from which lead bullets have been removed is finally supplied to a self-propelled reforming processing machine, and is mixed and reformed together with an additive. However, in the present invention, since lead bullets have already been removed when supplied to the self-propelled reforming processing machine, the additive does not necessarily have an exothermic action but has a solidifying action. What is necessary is just to have. Therefore, for example, various cements are also considered as additives.
[0014]
Therefore, in the present invention, the lead in the contaminated soil can be insolubilized and the lead bullets that are the source of contamination can be removed to prevent future contamination. Even if it exists, it can be reliably purified. Another advantage is that lead bullets can be removed by dry classification.
[0015]
(4) In the above (1) or (2), preferably, a refining means for receiving and refining the modified soil generated by the self-propelled reforming processing machine or the contaminated soil processing machine, It arrange | positions ahead of the said sorting machine.
[0016]
(5) In any one of the above (1) to (4), preferably, the self-propelled reforming processing machine or the reforming processing apparatus stores lime or a lime-based solidified material as the additive. A storage tank is provided.
[0017]
(6) In the above (3), preferably, the self-propelled reforming processing machine includes a storage tank that stores cement as the additive.
[0018]
(7) In any one of the above (1) to (6), more preferably, the sorting machine has a plurality of rod-shaped members arranged at intervals equal to or smaller than the particle diameter of the lead bullet. A sieve member is provided and configured.
[0019]
(8) In any one of the above (1) to (7), preferably, the fine particles for accepting and refining the contaminated soil before the self-propelled insolubilization processing machine or the contaminated soil processing machine Arranging means.
[0020]
(9) In any one of the above (1) to (8), more preferably, mixing means for mixing the modified earth and sand with a property of adsorbing heavy metal ions is further provided.
[0021]
(10) In order to achieve the above object, the contaminated soil treatment method of the present invention insolubilizes by supplying and mixing an insolubilizer for insolubilizing lead and water into contaminated soil mixed with lead ammunition as a contamination source. The treated soil is generated, and the modified soil is generated by supplying and mixing an additive having an exothermic effect to the insolubilized treated soil. Then, the modified soil is classified, and the lead bullet is extracted from the modified soil. Isolate.
[0022]
(11) In order to achieve the above object, the contaminated soil treatment method of the present invention supplies and mixes an insolubilizer for insolubilizing lead and water into contaminated soil mixed with lead ammunition as a contamination source. Generate insolubilized soil, classify the insolubilized soil, separate the lead bullets from the insolubilized treated soil, and then supply the solidified additive to the insolubilized soil separated from the lead bullets To produce modified soil.
[0023]
(12) In the above (10) or (11), preferably, the modified earth and sand are mixed with earth and sand having a property of adsorbing heavy metal ions.
[0024]
(13) In the above (12), preferably, clay is used as the earth and sand.
[0025]
(14) In any one of the above (10) to (13), more preferably, after the modified soil is accommodated in a hole whose inner wall surface is covered with viscous soil, the water is shielded and covered with the covered soil. .
[0026]
DETAILED DESCRIPTION OF THE INVENTION
In the embodiment of the contaminated soil treatment system of the present invention described below, for example, in a site where lead bullets are scattered, such as an outdoor shooting practice field, purification treatment of lead-contaminated soil containing lead bullets as a contamination source, or metal resources It is a system that functions effectively for the recovery of lead bullets. In addition, since it is assumed that the soil in a vast site is treated, the contamination distribution of lead contamination should be investigated in advance to identify the contamination range. However, the following embodiment is not limited to the shooting ground soil, and the same treatment is applied to soil in a similar environment (specifically, lead-contaminated soil containing lead as a solid content). Is something that can be done. Of course, simple lead-contaminated soil that does not contain lead solids can also be treated. Further, the present invention is not necessarily limited to the aspects of the following embodiments, and can be appropriately changed in design without departing from the technical idea thereof.
[0027]
FIG. 1 is a conceptual diagram schematically showing the steps of the embodiment of the contaminated soil treatment system of the present invention. In FIG. 1, the indispensable steps of the contaminated soil treatment system of the present invention are the step of insolubilizing the excavated lead-contaminated soil and the reforming (aggregation or solidification) of the insolubilized contaminated soil to generate modified soil. And a classification process for separating lead bullets (the order is not necessarily limited to this). For convenience, in the following description, these three processes will be collectively referred to as a “basic process”. The essential effects of the present invention can be obtained at least by performing this basic process.
[0028]
In the following embodiment, in addition to the above basic steps, other steps capable of obtaining a synergistic effect by selectively combining with the basic steps as necessary will be described together. . The “other processes” will be described in detail later, for example, a crushing process of contaminated soil, a second reforming process in which the modified soil is further mixed with an additive such as lime, or finally lead. A second insolubilization treatment step in which the modified earth and sand separated from the ammunition are mixed with viscous earth, and a water shielding treatment that completely prevents the elution of lead from the modified earth and sand. As long as an effect is obtained, it is not always necessary.
First, an embodiment of the contaminated soil treatment system of the present invention will be described below in order.
[0029]
[1] One embodiment
(1.1) Configuration
1.1-1: Basic process
Here, the system of the purification process part which consists of the insolubilization process and the modification process of lead contaminated soil among the basic processes in one Embodiment of the contaminated soil treatment system of this invention is demonstrated first using FIG. In FIG. 2, 100 is a hydraulic excavator that excavates contaminated soil and supplies it to the system, 200 is a self-propelled insolubilization processing machine that insolubilizes the contaminated soil introduced by the hydraulic excavator 100, and 300 is a self-propelled insolubilization processing machine 200. This is a self-propelled reforming machine that solidifies (aggregates) the treated soil that has been insolubilized.
[0030]
The hydraulic excavator 100 is a self-propelled type known as this type, and includes a traveling device 102 provided with an endless track crawler belt 101, a revolving structure 103 provided on the upper portion of the traveling device 102 so as to be capable of swiveling, And an articulated work device that is pivotally connected to the revolving structure 103. The working device 103 includes a boom 104 whose base end is pivotally supported by the swing body 103, an arm 105 rotatably connected to the boom 104, and a pivotally connected to the arm 105. The bucket 106 is configured. With this configuration, the excavator 100 scoops contaminated soil into the bucket 106 and supplies it to the self-propelled insolubilizing machine 200. The hydraulic excavator 100 is used as a contaminated soil supply means for supplying lead-contaminated soil to the self-propelled insolubilizing machine 200 as described above. In this case, other equipment such as a conveyor is used instead. You may arrange in.
[0031]
The self-propelled insolubilization processing machine 200 includes a sieving device 3, a hopper 4, a transport conveyor 5, an additive supply device 39, an insolubilizing agent supply device 6 (see FIG. 4 described later), a mixing device 7, a discharge conveyor 8, a power The apparatus 9 is mainly configured by a main body frame 10 that supports these devices, and a traveling device 45 provided at the lower portion of the main body frame (details of each device will be described later).
[0032]
FIG. 3 is a side view showing a detailed structure in the vicinity of the sieve device 3 and the hopper 4. The sieving device 3 shown in FIG. 3 is a pulverizing / classifying means for pulverizing the processing target contaminated soil (lead-contaminated soil) introduced by the hydraulic excavator 100 and the like according to the particle size. . As will be described later, in the present embodiment, the sieve device 3 is configured by a so-called vibrating sieve, but is not limited thereto, and may be a simple fixed sieve, and it is not always necessary to provide it. However, it can be changed and omitted as appropriate according to the properties of the contaminated soil.
[0033]
In this sieving device 3, reference numeral 11 denotes a frame constituting the main body of the sieving device 3, and this frame 11 is attached to a support member 13 provided on the main body frame 10 via a support post 12 via a spring 14. Elastically supported. Reference numeral 15 denotes a lattice member mounted in the frame 11, and 16 denotes a rotary drum inserted through a vibration shaft (not shown) of the lattice member 15. The rotary drum 16 is driven to rotate by a driving device (not shown). It is supposed to be.
[0034]
As a result, the vibration shaft (not shown) rotates and the sieve device 3 is vibrated, so that a large mass or the like contained in the input contaminated soil is crushed by the edge effect of the lattice member 15. At this time, since the frame body 11 is arranged such that the front side (left side in FIG. 3) is lower than the rear side (right side in FIG. 3), it is larger than the eyes of the lattice members 15 included in the input contaminated soil. A foreign substance such as a stone moves forward on the lattice member 15 and is discharged to the outside (in this case, the left side in FIG. 3). That is, components smaller than the eyes of the lattice member 15 are selected and introduced into the lower hopper 4. Reference numeral 17 denotes a so-called punch provided on the upper part of the sieve device 3.
[0035]
The hopper 4 is a frame-shaped member that receives the contaminated soil introduced from the above sieve device 3, and the upper end portion of the hopper 4 is inclined to the support member 13 so that the lower end portion thereof is inclined according to the inclination angle of the conveyor 5. It is fixed. Further, the hopper 4 has an upwardly expanded shape in order to reliably receive the contaminated soil from the sieve device 3. The dimension of the upper opening of the hopper 4 is slightly larger than the frame 11 of the sieving device 3 in both the longitudinal direction and the width direction, and the width of the lower end is the conveying belt 24 (described later) of the conveying conveyor 5. 4) is slightly smaller than the width. Thereby, the contaminated soil introduced from the sieving device 3 is guided onto the conveyor 5 without leaking. Although not shown in FIG. 2, the hopper 4 of the self-propelled insolubilization processing machine 200 is charged with contamination to improve the familiarity with the insolubilizing agent added later and facilitate the subsequent processing. A water supply channel 32aa (see FIG. 5 described later) for adding water to the soil is provided.
[0036]
An arch breaker 18 is provided in the hopper 4. The arch breaker 18 agitates and crushes the received contaminated soil, and breaks the bridge when a crosslinking phenomenon occurs. Reference numeral 19 denotes a rotation shaft of the arch breaker 18, and this rotation shaft 19 passes through the hopper 4 in the longitudinal direction (left-right direction in FIG. 3), and both ends of the hopper 4 have bearings (not shown). It is rotatably supported via. Reference numeral 20 denotes a stirring rod (blade). The stirring rod 20 is inclined in the hopper 4 by a predetermined angle with respect to a direction orthogonal to the axial direction of the rotating shaft 19, and at a predetermined pitch with respect to the rotating shaft 19. Is provided. Reference numeral 21 denotes a drive device for the arch breaker 18, and this drive device 21 is directly connected to an end portion (right end in FIG. 3) of the rotating shaft 19.
[0037]
That is, the arch breaker 18 is rotationally driven by the drive device 21 and agitates the contaminated soil introduced into the hopper 4 by the agitating rod 20 to prevent the occurrence of bridging in the lower part of the hopper 4 and promote the crushing of the contaminated soil. It is like that. However, this arch breaker 18 is not necessarily required, and may be omitted as appropriate depending on the properties of the contaminated soil.
[0038]
Returning to FIG. 2, the conveyor 5 is mounted on the front side (left side in FIG. 2) end of the main body frame 10. Further, the transport conveyor 5 extends upward from the lower side of the hopper 4 toward the downstream side (right side in FIG. 2).
[0039]
FIG. 4 is a diagram showing a detailed structure in the vicinity of the downstream side of the conveyor 5. In FIG. 4, 22 is a conveyor frame of the conveyor 5, and 23 is a drive wheel supported at the downstream end (right side in FIG. 4) of the conveyor frame 22. A conveyor belt 24 is wound around a driven wheel (not shown) supported at the upstream end (left end in FIG. 3). Then, the drive wheel 23 is rotationally driven by a drive device (not shown), whereby the transport belt 24 is driven to circulate and transport the contaminated soil in the hopper 4 to the downstream side.
[0040]
At this time, as shown in FIG. 4, an opening 4 a for cutting out contaminated soil having a predetermined opening area (predetermined height × width) is provided on the downstream side wall surface of the hopper 4 and is transported by the transport conveyor 5. The contaminated soil is cut out of the hopper 4 through the opening 4 a and guided to the mixing device 7. Reference numeral 25 denotes a restriction plate that prevents contaminated soil cut out of the hopper 4 from spilling out from the conveyor 5.
[0041]
Although not particularly illustrated, it is preferable to project a so-called lug on the conveying surface of the conveying belt 24 in order to prevent the contaminated soil from slipping. Further, the conveyor 5 is not limited to the belt conveyor as shown in FIG. 2, and a screw conveyor or the like may be adopted.
[0042]
Returning to FIG. 2 again, the additive supply device 39 is not necessarily used in the self-propelled insolubilizing machine 200 (that is, the insolubilizing process). However, the additive supply device 39 is also provided in the self-propelled reforming processing machine 300, and will be described later in the description of the self-propelled reforming processing machine 300.
[0043]
FIG. 5 is a diagram illustrating an extracted main part related to a series of processes in the process illustrated in FIG. As shown in FIG. 5, the insolubilizing agent supply device 6 includes supply pipes 27a and 27b (details will be described later), connection pipes 32a and 32b connected to the supply pipes 27a and 27b, and connection pipes 32a and 32a, respectively. The flow rate adjustment valves 33a and 33b are provided in 32b, respectively. As shown in FIG. 4, the supply pipes 27 a and 27 b are supported by a frame 26 that spans the regulation plate 25 of the transport conveyor 5 and the inlet 35 of the mixing device 7.
[0044]
Although not particularly shown in the present embodiment, the system shown in FIG. 2 is provided with a pump unit 28 (see FIG. 15) for storing an insolubilizing agent used in the self-propelled insolubilizing machine 200. It has been. The pump unit 28 includes storage tanks 29a and 29b shown in FIG. 5, pumps 30a and 30b for discharging the insolubilizing agents in the storage tanks 29a and 29b, and a base frame 31 (see FIG. 15) on which these are mounted. It consists of In the present embodiment, the storage tanks 29a and 29b store water and an aqueous solution of an insolubilizing agent (for example, sodium sulfide or sodium hydrosulfide). Further, it is considered that the insolubilizing agent is supplied in a state dissolved in water in advance, not in powder form, so that the insolubilizing agent quickly penetrates into the contaminated soil and efficiently reacts with lead in the contaminated soil. Further, by supplying water here, the insolubilizing agent and the contaminated soil are uniformly mixed. As shown in FIG. 5, the supply pipes 27a and 27b are connected to the storage tanks 29a and 29b, respectively.
[0045]
In this embodiment, the pump unit 28 is separately installed. However, when the pump unit 28 is operated at a site where the amount of processing is relatively small and a large amount of insolubilizer is not required, the pump unit 28 is small. If sufficient, it may be configured to be incorporated into the self-propelled insolubilizing machine 200 as appropriate. In the present embodiment, water and an aqueous solution of an insolubilizing agent are separately supplied from the supply pipes 27a and 27b, respectively, but the present invention is not limited thereto. That is, as long as water and an insolubilizing agent are supplied to the contaminated soil, for example, both may be stored in the same tank in advance, mixed and supplied from a common supply pipe by stirring.
[0046]
FIGS. 6A and 6B are diagrams showing the structure of the supply pipes 27a and 27b. First, as shown in FIG. 6 (a), the supply pipe 27a (FIG. 6 (a) shows the supply pipe 27a as an example, but the supply pipe 27b is also the same). It is the character shape. The supply pipe 27a has a central part 27aa to which the connection pipe 32a (see also FIG. 5) is connected and an end part 27ab bent from the central part 27aa. The central part 27aa and the end part 27ab A large number of holes 34 are provided inside. Further, the interval between the end portions 27ab (that is, the length of the substantially central portion 27aa) is substantially equal to the width dimension of the inlet 35 (see FIG. 4) of the mixing device 7, and the hole 34 of the central portion 27aa is formed in the transport conveyor 5. The frame 26 (see FIG. 4) is attached to the frame 26 (see FIG. 4), for example, by welding or the like so as to face each other and to be positioned almost directly above the inlet 35.
[0047]
Thereby, the insolubilizing agent supply device 6 flows out the water pumped from the pump unit 28 and the aqueous solution of the insolubilizing agent through the holes 34 of the supply pipes 27a and 27b, respectively. Thereby, the insolubilizing agent is added to the contaminated soil discharged from the downstream end of the conveyor 5 by the insolubilizing agent supply device 6 from the periphery during the discharge. These contaminated soil and insolubilizing agent are supplied to the mixing device 7.
[0048]
The supply pipes 27a and 27b may have a substantially “one” character shape as shown in FIG. 6B. In this case, the holes 34 are opposed to the conveyor 5 (strictly, the conveyance What is necessary is just to attach to the said frame 26 so that the contaminated soil discharged | emitted from the conveyor 5 may be countered.
[0049]
Returning to FIG. 2 again, the mixing device 7 uniformly agitates the received contaminated soil and the insolubilizing agent and derives it as insolubilized treated soil. The longitudinal direction (left and right direction in FIG. 2) of the main body frame 10 is substantially above the center. Installed on. The mixing device 7 has an inlet 35 (see FIG. 4) for contaminated soil and an insolubilizing agent on the upper side of one side (left side in FIG. 2), and an outlet (not shown) for the insolubilized soil in the lower side on the other side (right side in FIG. 2). )). The mixing device 7 includes a plurality of paddle mixers (not shown) provided substantially in parallel as stirring means, although not particularly shown for preventing congestion, and is introduced through the inlet 35 by the paddle mixer. The contaminated soil and the insolubilizing agent are mixed, and the generated insolubilized soil is led out from the outlet. A drive device 36 drives the paddle mixer.
[0050]
The discharge conveyor 8 discharges the insolubilized soil derived from the mixing device 7 out of the self-propelled insolubilizing machine 200 and conveys it toward the self-propelled reforming processing machine 300. The discharge conveyor 8 extends substantially horizontally for a predetermined distance from the lower side of the outlet (not shown) of the mixing device 7 toward the other side (the right side in FIG. 2), and then inclines upward from below the driving device 36 of the mixing device 7. It is extended. Reference numeral 37 denotes a conveyor frame of the discharge conveyor 8. The conveyor frame 37 is supported from the power unit 9, the main body frame 10 and the like by a support member (not shown).
[0051]
In addition, although the discharge conveyor 8 was illustrated as a belt conveyor, it is not restricted to this. In the mixing device 7, since the insolubilized soil and the water are mixed with the contaminated soil, the insolubilized soil is in a slurry state. Therefore, the discharge conveyor 8 that transports the insolubilized soil may be a screw conveyor, for example. good. Alternatively, a pressure pump or the like may be employed instead.
[0052]
Although not specifically shown, the power unit 9 is supplied to an engine as a power source of the driving device of each device described above, a hydraulic pump driven by the engine, and a driving device of each device from the hydraulic pump. A plurality of control valves for controlling pressure oil are provided. The power unit 9 is supported by a support member 38 at the other end (right side in FIG. 2) in the longitudinal direction of the main body frame 10.
[0053]
The traveling device 45 includes a track frame 46 provided continuously below the main body frame 10, driven wheels (idlers) 47 and drive wheels 48 provided at both ends of the track frame 46, and the driven wheels 47 and drive wheels 48. An endless track crawler belt 49 and a drive device 50 directly connected to the drive wheel 48 are configured. Thereby, self-propelled insolubilization processing machine 200 can be run on its own.
[0054]
The insolubilized soil that has been insolubilized by the self-propelled insolubilizing machine 200 configured as described above is then supplied to the self-propelled reforming processing machine 300.
[0055]
The self-propelled reforming processing machine 300 has substantially the same configuration as the self-propelled insolubilization processing machine 200 except that the sieving device 3 and the insolubilizing agent supply device 6 are omitted. Portions that are the same as or similar to those of the processing machine 200 are denoted by the same reference numerals in FIG.
[0056]
Here, the configuration of the additive supply apparatus 39, the description of which is omitted in the configuration of the self-propelled insolubilization processing machine 200, will be described. However, as described above, the additive supply device 39 is also provided in the self-propelled insolubilization processing machine 200 and has the same configuration as that of the self-propelled reforming processing machine 300. The additive material supply device 39 includes a substantially cylindrical additive material storage tank 40 and a feeder 41 (see also FIG. 4) for leading the additive material in the storage tank 40 downward.
[0057]
The storage tank 40 includes a bottomed cylindrical lower tank portion 42, a bellows-like upper tank portion 43 connected to the upper portion thereof, and a top plate portion 44 that covers the upper portion of the upper tank portion 43. Yes. Thus, for example, during operation, the internal volume of the storage tank 40 is sufficiently secured by extending the bellows-like upper tank portion 43 (state shown in FIG. 2). Conversely, when transporting, etc., by fully contracting the upper tank portion 43, when transporting the self-propelled insolubilization processing machine 200 with a trailer or the like, the total height can be reduced to a height that clears the transport restrictions. Yes. Further, a cutting means (not shown) is provided at the bottom of the lower tank portion 42, and the additive material in the storage tank 40 is smoothly cut out to the feeder 41 by the cutting means.
[0058]
The feeder 41 (see also FIG. 4) is a so-called rotary feeder, and has a rotor with a plurality of partition walls projecting radially on a rotating shaft, although not particularly shown for preventing congestion. Then, the additive introduced from the storage tank 40 into the space between the partition walls of the rotating rotor is sequentially added to the processing soil conveyed on the conveyor 5. In the present embodiment, the feeder 41 is a rotary feeder. However, the feeder 41 is not limited to this, and may be a screw feeder, for example.
[0059]
In addition, as an additive added here, what has a heat_generation | fever action is preferable, for example, powders, such as a lime, a lime type solidification material, iron, iron oxide, aluminum, etc. are mentioned typically. However, iron, iron oxide, and aluminum powders that are not too small in particle size need to be used for safety considerations. On the other hand, if the particle size is too large, even if it is mixed with the contaminated soil, it will be scattered in the contaminated soil. It is better to use
[0060]
With the above configuration, in the system shown in FIG. 2, when lead-contaminated soil is introduced into the self-propelled insolubilizing machine 200 by the hydraulic excavator 100, the insolubilized soil that has been insolubilized here is self-propelled reforming treatment. It is introduced into the machine 300, mixed with the additive, and discharged in the form of agglomerated. This modified earth and sand is cured for a predetermined time in an accumulation place (not shown), and the reaction proceeds sufficiently.
[0061]
Next, of the basic steps in one embodiment of the contaminated soil treatment system of the present invention, a sorting machine used for the step of classifying the modified soil treated by the system of FIG. 2 will be described with reference to FIG. In FIG. 7, reference numeral 400 denotes the sorting machine, and the sorting machine 400 is constituted by a so-called vibrating sieve as in the above-described sieve device 3. Reference numeral 401 denotes a sieve device that receives the cured modified earth and sand and removes foreign matters such as lead bullets and gravel, and 402 is a substantially frame-shaped sieve device body. The sieving device 402 is elastically supported on a support base 402 via a spring 403, and can be vibrated by a vibration device (not shown).
[0062]
Reference numeral 404 denotes a sieving member for sorting and moving lead. The sieving member 404 is formed of a so-called harp screen as shown in FIG. This sieve member 404 is formed by arranging rod-like members 404a extending in the moving direction of lead bullets (left direction in FIG. 7) at narrow intervals (equal to or less than the particle diameter of lead bullets). A slit-like gap is formed between 404a. As a result, the modified soil put on the sieve member 404 is classified by the vibrating sieve member 404, and a soil component smaller than the gap on the slit is introduced downward. On the other hand, lead bullets, gravel and the like having a particle size larger than the gap move on the sieve member 404 and are separated and removed.
[0063]
As shown in FIG. 7, the sieve member 404 is inclined downward on the left side in the figure, and the separated lead bullets etc. move on the sieve member 404 to the left side in FIG. 7 and through the chute 405. It is supposed to be discharged. In FIG. 8, reference numeral 404b denotes a reinforcing member for the rod-shaped member 404a, which is supported from the lower side so as to be orthogonal to each rod-shaped member 404a, and is arranged in a relatively large interval.
[0064]
Reference numeral 406 denotes a ring for smooth introduction of the modified earth and sand into the sieve device 401, and this ring 406 is supported on the main body frame 402 via a support post 407 so as to come above the sieve device 401. . Reference numeral 408 denotes a discharge conveyor that conveys the modified soil having a predetermined particle size or less classified by the sieving device 401 toward the right side in FIG. 7, and this conveying conveyor 408 is arranged from below the sieving device main body 402. The conveyor frame 409 is supported by the support members 410 and 411 so as to rise upward toward the downstream side in the transport direction (right side in FIG. 7).
[0065]
With such a configuration, the sorting machine 400 classifies the supplied modified earth and sand with the sieve device 401, and discharges the modified earth and sand from which lead bullets have been removed while discharging lead bullets and the like through the chute 405. It is carried out via the conveyor 408. And the modified earth and sand from which the lead bullets have been removed is used as, for example, backfilling soil, and the separated lead bullets are reused as metal resources.
[0066]
Note that the sorting machine 400 in FIG. 7 simply separates the lead bullets and the modified earth and sand, but the sieve member 404 is provided in multiple stages, for example, the sorting object is less than 2 mm, 2-5 mm, 5-5 It is good also as a structure sorted according to a particle size like 10 mm, 10 mm or more. The particle size of the lead bullets scattered in the shooting range is usually about 2 to 4 mm. With such a configuration, most of the lead bullets are collected in a range selected with a particle size of 2 to 5 mm. Become. In addition, what is collected in the particle size range of 2 to 5 mm (or its peripheral range) may contain gravel or earth clumps mixed with lead bullets. There is also a method of separating lead bullets by inertia using the difference in specific gravity.
[0067]
Although the basic process in one embodiment of the contaminated soil treatment system of the present invention is as described above, there are various other additional processes as a process for performing a more reliable purification process of lead-contaminated soil. Conceivable.
Hereinafter, in order to more reliably perform the purification treatment of the contaminated soil, processes considered as combinations with the basic processes are sequentially exemplified as other processes (selective processes).
[0068]
1.1-2: Other processes
i) Disintegration process
Since the contaminated soil to be treated is excavated soil by the hydraulic excavator 100, in many cases, the contaminated soil is in a state containing a lot of soil blocks. If the soil contains a large amount of soil, the insolubilizing agent is hardly mixed uniformly, and sufficient processing efficiency may not be obtained.
[0069]
The crushing process described here is insolubilized with lead dissolved in the soil by refining the contaminated soil when the crushing process is placed in the previous stage of the self-propelled insolubilizing machine 200 shown in FIG. The agent can be mixed evenly and contributes to the improvement of the processing efficiency.
Moreover, when a crushing process is put in the latter stage process of the self-propelled reforming processing machine 300, the modified soil is further refined and contributes to the improvement of classification by the sorting machine 400. In addition, after curing the modified earth from the self-propelled reforming processing machine 300, if the state of the modified earth is not yet sufficient to be sent to the classification process by the sorting machine 400, it is revised again. In some cases, a quality treatment (second modification step described later) is performed. Even if the following crushing step is provided before or after the second reforming treatment step, of course, the modified earth and sand can be refined to contribute to further efficiency of separation of lead bullets. is there.
[0070]
FIG. 9 is a side view showing the entire structure of a crushing conveyor device that crushes contaminated soil or treated soil as an example of an apparatus used in this crushing step. In FIG. 9, reference numeral 501 denotes a crushing conveyor apparatus body that performs the basic functions of the crushing conveyor apparatus 500, and this crushing conveyor apparatus body 501 is supported by a support member 505. The crushing conveyor device body 501 includes a hopper 502 that receives the supplied contaminated soil and treated soil, a conveyor 503 that conveys the contaminated soil and treated soil received by the hopper 502 in the right direction in FIG. It is composed of at least one (two in this example) crushing device 504 that crushes contaminated soil and treated soil conveyed by the conveyor 503. The crushing apparatus 504 has a rotating body provided so that the rotation trajectory of the crushing blade is close to the conveying surface of the conveying conveyor 501.
[0071]
With the above configuration, the crushing conveyor device 500 conveys the contaminated soil and the treated soil received in the hopper 501 by the conveying conveyor 501, and crushes and fines the particles by the crushing device 504 during the conveyance.
[0072]
In the state shown in FIG. 9, the crushing conveyor device 500 does not have a self-propelling function. However, the traveling device may be provided with a self-propelling function. Moreover, it is good also as a structure which provides an additive supply apparatus in this crushing conveyor apparatus 500, and crushes contaminated soil and treated soil with an additive. Furthermore, as long as the contaminated soil and the treated soil are crushed, the apparatus is not limited to the pulverizing conveyor device 500 of FIG. 9, for example, a mixing device using a paddle mixer, a mixing device using a rotary hammer, or a vibration feeder. Arrangement is also possible.
[0073]
ii) Second modification process
In this process, in FIG. 2, after the treated soil from the self-propelled reforming processing machine 300 is cured, the treated soil is still in a state sufficient to be sent to the classification process by the sorting machine 400. If not, the reforming process is performed again. As a result, the plasticity of the modified soil is sufficiently lowered and sent to the classification process, which contributes to securing the classification property.
[0074]
As an apparatus used for the second reforming process, the above-described self-propelled reforming processing machine 300 may be used. In this case, the self-propelled reforming processing machine 300 of FIG. It may be prepared separately. That is, if the plasticity is not sufficiently lowered even after curing the modified soil from the self-propelled reforming processing machine 300 of FIG. 2, the modified soil is removed from the hydraulic excavator 100 (also shown in FIG. 2). Can be used together or prepared separately) and then added to the hopper 4 of the self-propelled reforming processing machine 300, and further added and mixed to sufficiently plasticize the modified soil. Lower the value and send it to the classification process.
[0075]
As long as the additive and the modified earth and sand are mixed, it is not necessarily limited to the self-propelled reforming processing machine 300, and the self-propelled insolubilizing processing machine 200 may be used. A self-propelled soil improvement machine may be used. Furthermore, a method of stirring the modified earth and additive with the front device of the excavator 100 is also conceivable.
[0076]
iii) Second insolubilization process
In this step, the modified earth and sand treated in the series of steps described above are mixed with the earth and sand having the property of adsorbing heavy metal ions. Specifically, clay soil is used as the earth and sand, and for example, clay components (but not contaminated) of the soil of the land where the contaminated soil to be treated is present are sufficient. That is, in the modified soil treated through the above basic steps, even if lead was not sufficiently insolubilized, and then lead may be eluted by acid rain, By mixing with cohesive soil or the like, lead ions are adsorbed to completely prevent elution.
[0077]
The mixing means for mixing the modified soil and the viscous soil is not particularly limited. For example, a known self-propelled soil conditioner or the like is used, and the modified soil and the viscous soil are automatically separated by a hydraulic excavator or the like. What is necessary is just to throw into a traveling type soil conditioner and to mix with the mixing apparatus. Of course, as long as this is the case, the self-propelled insolubilization processing machine 200 and the self-propelled reforming processing machine 300 of FIG. 2 can be similarly applied, and a general mixing device (mixer) or the like may be used. Furthermore, a method of stirring viscous soil and modified soil with a front device of a hydraulic excavator or the like is also conceivable.
[0078]
iv) Water shielding treatment
FIG. 10 is a diagram schematically illustrating an example of a state in which the modified earth and sand is subjected to a water shielding treatment and backfilled on the ground surface. As shown in FIG. 10, the modified soil is backfilled in a hole whose inner wall is covered with a clay layer 601. In this way, the clay layer 601 covers the periphery of the modified earth and sand, and here again, the above-described adsorption effect is used to further improve the shielding structure with the surrounding soil.
[0079]
Further, the upper surface of the modified earth and sand is covered with an impermeable sheet 602 to prevent rainwater and the like from entering the modified earth and sand. The water-impermeable sheet 602 is further covered with a cover soil 603, and a groove 604 is provided around the cover soil 603. The upper surface of the covering soil 603 is formed so as to be inclined downward toward the groove 604, and rainwater is guided to the groove 604 through the covering soil 603 and drained. Invasion of rainwater is further prevented. In this way, the possibility of lead elution can be almost completely eliminated by blocking rainwater and backfilling it with the surrounding area covered with viscous soil.
[0080]
By combining the steps as exemplified above as appropriate with respect to the basic steps as described above, the contaminated soil purification treatment and lead bullet separation in the present embodiment can be performed more effectively. (Details will be described later).
[0081]
(1-2) Operation
Here, the operation of the basic process of the contaminated soil treatment system of the present embodiment having the above configuration will be described. First, in FIG. 2, when contaminated soil contaminated with lead is introduced into the sieve device 3 of the self-propelled insolubilization processing machine 200 using a hydraulic excavator 100 or the like, large stones, rubble, and the like are formed in the lattice member 15 (see FIG. 3). The contaminated soil component that has been removed and passed through the grid member 15 is introduced into the lower hopper 4. By this classification, the particle size distribution is made uniform and becomes a size suitable for later mixing with the insolubilizing agent. At this time, when the lattice member 15 vibrates, a mass of soil larger than the eyes of the lattice member 15 is spun up and falls again on the lattice member 15. By repeating such an operation, when the earth lump is crushed by the impact at that time and the edge effect of the mesh (or may be a blade) of the lattice member 15 and becomes smaller than the eyes of the lattice 15, it is introduced into the hopper 4. The
[0082]
Also, the contaminated soil received by the hopper 4 is placed on the conveyor 5 below the crushed soil mass by the arch breaker 18 (see FIG. 3) provided in the hopper 4 while being crushed. . At this time, the water in the storage tank 29a is sprinkled into the hopper 4 through the above-described hydration conduit 32aa so that the subsequent oxidation-reduction reaction is promoted, and moisture is contained in the contaminated soil. This moisture is uniformly stirred and mixed with the contaminated soil in the hopper 4 by the arch breaker 18.
[0083]
The contaminated soil placed on the transport conveyor 5 is transported to the rear side and cut out of the hopper 4 through the opening 4a (see FIG. 4). In this case, the contaminated soil cut out from the hopper 4 is stirred by the arch breaker 18 and even if a relatively large soil block remains at the stage of cutting, the soil soil is crushed here. When this contaminated soil is discharged from the conveyor 5 toward the mixing device 7, the insolubilizing agent is supplied from the insolubilizing agent supply device 6.
[0084]
The contaminated soil introduced into the mixing device 7 is uniformly stirred and mixed together with the insolubilizer introduced together. At this time, if the residence time is secured by adjusting the operating state of the mixing device 7, the insolubilization treatment can be promoted by sufficiently stirring. In this case, the drive speed of the paddle mixer of the mixing device 7 may be simply slowed down, or the paddle mixer may be rotated forward and backward as appropriate, and the processing soil may be fed back as appropriate. Further, structurally, an appropriate number of paddles provided in the paddle mixer may be inclined so that the treated soil is fed back, or a weir may be provided near the outlet of the mixing device 7. The outlet opening area may be made small.
[0085]
By uniformly mixing with the insolubilizing agent in this way, lead contained in the contaminated soil is insolubilized by the reaction shown below.
Pb ²⁺ + S ^2- → 2PbS ↓
However, this formula can be applied to lead contaminated soil with sodium sulfide (Na ₂ When S) is mixed. As the lead insolubilizer, sodium hydrosulfide (NaHS) or the like may be used, or a chelating agent may be mixed with an aqueous solution to adsorb lead ions.
[0086]
Then, the insolubilized soil generated by the self-propelled insolubilizing machine 200 is led out of the mixing device 7 and supplied to the self-propelled reforming processing machine 300 by the discharge conveyor 8.
[0087]
The treated soil supplied from the self-propelled insolubilization processing machine 200 is received by the hopper 4 of the self-propelled reforming processing machine 300, and is stirred therein by the arch breaker, where it is further uniformly mixed with the insolubilizing agent. . The treated soil in the hopper 4 is cut out of the hopper 4 by the conveyor 5. Then, in the vicinity of the downstream end of the transport conveyor 5 in the transport direction, the additive in the storage tank 40 is supplied via the feeder 41 by the additive supply device 39 to the processing soil being transported. Thus, the treated soil on the conveyor 5 is uniformly stirred and mixed in the mixing device 7 together with the additive supplied together, and solidified (aggregated) by an ion exchange reaction with the additive to form a treated plastic having low plasticity. Reformed.
[0088]
The treated soil discharged from the self-propelled reforming processing machine 300 is cured for a predetermined period and supplied to the sorting machine 400 by the excavator 100 or the like. The sorting machine 400 removes lead bullets and discharges them. Finally, the separated lead bullets are reused as metal resources, while the treated soil is used as backfill soil or the like.
[0089]
Although the operation of the basic process is as described above, as described above, various processes are selectively combined according to the processing state if necessary.
[0090]
For example, when the state of the contaminated soil to be treated is poor (for example, when it is highly viscous or contains a large amount of soil mass), the above-described crushing process is performed before the self-propelled insolubilizing machine 200. The contaminated soil that has been provided and finely divided may be supplied to the self-propelled insolubilizing machine 200. The crushed contaminated soil may be stocked and supplied to the self-propelled insolubilization processing machine 200 by the hydraulic excavator 100, or the crushing conveyor device 500 or the like may be arranged in tandem on the self-propelled insolubilization processing machine 200 and crushed. You may supply directly to the self-propelled insolubilization processing machine 200 from the conveyor apparatus 500. FIG.
[0091]
Further, in the above basic process, after the treated soil from the self-propelled reforming processing machine 300 is cured, the state of the treated soil is not yet sufficient to be sent to the classification process by the sorting machine 400. Then, the second reforming process described above is performed, and the plasticity of the treated soil is sufficiently lowered and sent to the classification process. In this case, the self-propelled reforming processing machine 300 is arranged in tandem in the preceding stage of the sorting machine 400 so that the treated soil further mixed with the additive in the self-propelled reforming processing machine 300 is supplied to the sorting machine 400 directly. Alternatively, it may be cured before being supplied to the sorting machine 400. Moreover, you may perform said crushing process in the front | former stage or back | latter stage of this 2nd modification | reformation process process.
[0092]
Moreover, when it is desired to perform a more thorough insolubilization treatment, the second insolubilization treatment step described above may be performed after the basic step, and the treated soil may be mixed with the viscous soil. Further, when the treated soil is finally backfilled, the water shielding treatment as described with reference to FIG. 10 is performed to shield the treated soil and backfill with the surroundings covered with the viscous soil. good.
[0093]
(1-3) Action
Below, the effect acquired by the above-mentioned contaminated soil processing system of this Embodiment is demonstrated sequentially.
[0094]
i) Response to contaminated soil mixed with lead bullets
In conventional heavy metal-based contaminated soil treatment, the contaminated soil is simply insolubilized and solidified, and when contaminated soil containing a lead source called lead bullet is treated, the pollution source (lead bullet) cannot be removed. It was not possible to cope with it. Moreover, even if the lead bullets are removed, the lead bullets scattered in the shooting range or the like usually contain shots, and since there are many small particles with a particle diameter of about 2 to 4 mm, they are fine. It is necessary to use a sieve.
[0095]
However, the shooting range is often located in the middle of the mountain, and the contaminated soil to be treated is often a mountain soil (for example, weathered granite masa soil, loam clay soil, etc.). Therefore, if a fine sieve is used, the clay in the contaminated soil will adhere to the sieve and clogging will occur, so it was difficult to separate lead bullets by simply passing the contaminated soil over the sieve. .
[0096]
Therefore, in the present embodiment, first, the self-propelled insolubilization processing machine 200 insolubilizes the contaminated soil in a state including lead bullets, and the insolubilized processing soil is converted into the self-propelled reforming processing machine 300. Then, it is mixed with the additive and classified as a modified soil. By mixing such additives in the reforming step, moisture can be vaporized by the exothermic action of the additive to reduce the water content ratio of the insolubilized treated soil, thereby producing modified soil with low plasticity. Moreover, when lime (or lime-based solidification material) is added as an additive, particles of insolubilized soil are aggregated by an ion exchange reaction, and a modified soil that is easier to handle in a subsequent classification step may be generated. it can. In addition, such modified earth and sand reacts during the curing period and becomes more easily handled.
[0097]
As a result, the modified earth is not easily attached to the eyes of the sieve member 404 of the sorting machine 400 in the lead bullet separation step, and the soil is easily separated from each other, and the lead bullet can be separated from the modified earth and sand. Become. Therefore, it is possible to insolubilize lead in contaminated soil and remove the lead bullets that are the source of contamination to prevent future contamination. Can be purified.
[0098]
FIG. 11 is a diagram showing the weight ratio of each particle size range of the contaminated soil and the modified soil subjected to the above treatment. As shown in FIG. 11, the untreated contaminated soil has the highest ratio of particles having a particle size exceeding 4.75 mm. This is because contaminated soils adhere to each other on a sieve and a mass of soil is formed. On the other hand, the ratio of those having a particle diameter of less than 2 mm becomes the highest when the above-mentioned treatment is performed by adding an additive (in this case, quick lime).
[0099]
This is because when mixed with quicklime, the water content is reduced due to the exothermic effect, and the water content ratio is reduced, and the agglomeration occurs to prevent adsorption between viscous soils by the ion exchange reaction, resulting in a very low clay. It is because. As can be seen from FIG. 11, the larger the amount of the additive (quick lime) added, the more remarkable the action, and the desired property can be obtained by adjusting the addition rate of the additive according to the state of the contaminated soil to be treated. Can be produced. As described above, according to the present embodiment, it is possible to generate modified earth and sand that is very easy to handle in the classification process, so that separation of lead bullets is facilitated.
[0100]
ii) Lead bullet separation by dry classification
By the way, as a method for treating contaminated soil containing lead bullets, the following three methods may be mentioned.
The first method is to shield the soil contaminated area with a sheet pile, etc., and pump up the groundwater to purify the groundwater.
The second method is a method of excavating contaminated soil and taking it outside, and backfilling clean soil instead.
The third method is a purification method after removing the contamination source (lead bullet).
[0101]
The first method is not a fundamental measure because it only prevents the spread of contaminated water to the surrounding environment and the contamination remains. In the second method, the taken-out contaminated soil is processed at the final disposal site, which is not desirable because of the limit of the capacity of the final disposal site. On the other hand, in the third method, the pollution source is removed, and the pollutant in the contaminated soil from which the pollution source has been removed is insolubilized, and it is possible to perform on-site treatment without taking the contaminated soil to the outside. By removing the contamination source, subsequent contamination can also be prevented. Therefore, it can be said that the third method is the most preferable among the above.
Although the present embodiment belongs to the third method, the following technical problems exist in the separation of lead ammunition from contaminated soil.
[0102]
Conventionally, when a relatively small substance such as about 2 to 4 mm is separated from the earth and sand, it is common to employ a wet classification in which classification is performed while sprinkling water on the sieve surface in the form of a shower. However, if the earth and sand is sandy, it is easy to pass through the sieve, so lead bullets can be separated even with dry classification. In the case of the target, it was still difficult with dry classification.
[0103]
Here, a contaminated soil treatment system in the case where the lead ammunition is previously separated by wet classification and the contaminated soil from which the lead ammunition has been removed is insolubilized is shown in FIG. 12 as a comparative example with the present embodiment. As shown in FIG. 12, in this comparative example, first, foreign matters such as large gravel are removed from excavated contaminated soil, and lead bullets are removed by wet classification. In this example, by this wet classification, sieves are provided in a multistage manner and sieved to those having a particle size of less than 2 mm, 2 to 5 mm, and 5 mm or more. As described above, since the lead bullet is about 2 to 5 mm, the lead bullet is recovered as a metal resource from the sorted particle size of 2 to 5 mm. At this time, small gravel or the like may be mixed in a particle having a particle diameter of 2 to 5 mm. For example, the lead ammunition is separated using inertia from the difference in specific gravity between lead and gravel. Thereafter, those having a particle diameter of 2 mm or less (contaminated soil) are dehydrated by a thickener and a press so that they can be processed as a so-called dehydrated cake. Then, the contaminated soil that becomes the dehydrated cake is purified, cured, and then backfilled.
[0104]
However, in the above comparative example, when removing large gravel and lead bullets, the contaminated soil is classified by wet classification, so the water sprinkled here is newly contaminated, and this water treatment system Also contaminated. That is, the contamination range is expanded. In addition, thickeners and presses to make dehydrated cake from contaminated soil that has undergone wet classification are required, and the system becomes very expensive and large-scale, which may make it difficult to introduce it on site. .
[0105]
On the other hand, in the present embodiment, as described above, the contaminated soil is insolubilized and further modified to be easy to handle, and then the lead bullet classification process is performed without using so-called wet classification. The lead bullets can be separated by dry classification. Further, no water treatment system for washing is required, and the occurrence of new contamination as described above can be prevented. Furthermore, the minimum necessary machines (machines necessary for the basic process) are only the self-propelled insolubilization processing machine 200, the self-propelled reforming processing machine 300, and the sorting machine 400, which are comparative examples that require thickeners, presses, and the like. On the other hand, a simple, low-cost and further compact system can be configured, and the processing cost can be reduced accordingly.
[0106]
iii) Improved processing efficiency
Since the contaminated soil to be treated is excavated soil, it is often in a state containing a lot of soil blocks as it is. If the soil contains a large amount of soil, the insolubilizing agent is hardly mixed uniformly, and sufficient processing efficiency may not be obtained.
[0107]
Therefore, for example, the contaminated soil to be treated is preliminarily refined by a finer means for refining the contaminated soil, such as the crushing conveyor device 500 shown in FIG. And the insolubilizing agent can be mixed uniformly, and the insolubilization reaction can proceed more effectively. In addition, by preliminarily contaminating the contaminated soil, the passability of the sieving device 3 of the self-propelled insolubilization processing machine 200 is improved, and the working efficiency is improved. As a result, the processing efficiency of contaminated soil can be improved.
[0108]
In addition, when the fine granulating means is arranged in the subsequent stage of the self-propelled reforming processing machine 300 (the preceding stage of the sorting machine 400), the modified soil is further refined so that the classification by the sorting machine 400 is improved. This can also improve the treatment efficiency of contaminated soil. In addition, as long as the classification by the sorting device 400 is improved as described above, in short, it is only necessary to arrange the finer means in the preceding stage of the sorting device 400. For example, the reforming process is performed again depending on the state of the modified soil. In some cases, it is needless to say that the same effect can be obtained by disposing the finer means before or after the reforming process.
[0109]
iv) Improved classification
In the basic process of this embodiment, such as insolubilization → solidification (aggregation) → classification, when the modified soil after the modification treatment is still cured, the plasticity has not decreased to a level sufficient for classification As described with reference to FIG. 11, the plasticity can be sufficiently lowered by subjecting the modified soil after curing to the second modification step described above and further mixing with the additive. By increasing the mixing ratio of the additive as described above, the plasticity of the modified earth and sand is lowered, the earth and sand are easily separated from each other, and the modified earth and sand can be further modified to be easily classified. As a result, the classification property in the classification process can be improved.
[0110]
v) Improved certainty of insolubilization treatment
The modified earth from which lead bullets have been removed and subjected to purification treatment through the above basic process is in a state where lead contained therein is sufficiently insolubilized, and thus can be used as backfill soil. As described above, as the second insolubilization process step, a more thorough insolubilization process can be performed by mixing the modified earth and sand with a property of adsorbing heavy metal ions (viscous soil). That is, even if lead is eluted from the modified earth for some reason, the eluted lead can be adsorbed by the viscous soil, and lead elution can be completely prevented.
[0111]
FIG. 13 is a diagram comparing the amount of pollutant elution between contaminated soil and a mixture of contaminated soil with viscous soil. In FIG. 13, the result of the elution test on the test soil produced by mixing hexavalent chromium and arsenic into the earth and sand in addition to lead as a pollutant is shown as a comparison target. In the figure, for each item of lead, hexavalent chromium, and arsenic, the amount of contaminants mixed with the test soil is shown on the left side, and the amount of contaminants extracted from the test solution by the dissolution test on the right side (elution amount). ). However, this elution amount is an elution ratio when the added amount of the mixed contaminant is 100%.
[0112]
As shown in FIG. 13, the effect of insolubilizing contaminants is observed in each of lead, hexavalent chromium, and arsenic. In particular, a high insolubilizing effect was observed for lead and arsenic, and the results of almost completely suppressing the elution of pollutants were obtained only for lead. As can be seen from the result, lead is eluted from the modified soil by mixing the modified soil already insolubilized with the viscous soil in the second insolubilization process. However, it will be adsorbed by cohesive soil and can be thoroughly insolubilized.
[0113]
Moreover, the effect of adjusting the moisture content ratio of the modified soil and the effect of bringing the modified soil having a high pH due to the insolubilization process back to neutrality and a stable state can be obtained by mixing the viscous soil.
[0114]
vi) Improved certainty of lead elution prevention
As described above with reference to FIG. 10, the modified earth and sand are filled in the hole whose inner wall surface is covered and solidified by the clay layer 601, covered with the water-impervious sheet 602, and further, the covering soil 603 causes rainwater to flow around the surrounding groove 604. By refilling the modified earth and sand with a structure that can be guided to, elution of lead can be almost completely prevented.
[0115]
That is, by covering the modified soil with viscous soil that has an effect of adsorbing lead, the clay layer 601 blocks outflow of contamination to the surrounding soil even if lead is eluted from the modified soil. Is done. Moreover, since water, such as rain water, is blocked by the water shielding sheet 602, moisture to the modified earth and sand can be blocked and a factor of lead elution can be prevented beforehand. Moreover, since the top of the water-impervious sheet 602 is further covered with the cover soil 603 that leads to the groove 604 for draining rainwater, this makes it possible to prevent water from entering the modified soil. As a result, an almost complete effect of preventing lead elution can be obtained.
[0116]
vii) Shortening the construction period
Since reforming of contaminated soil requires a plurality of processes, it is common to arrange various stationary equipment such as a conveyor, a mixing device, and a supply device of contaminated soil and chemicals. Therefore, there is a tendency that the construction period for carrying out the system carrying-in work, the contaminated soil purification processing work, and the system carrying-out work is prolonged.
[0117]
Therefore, in the present embodiment, if a machine capable of performing each process independently such as a self-propelled insolubilization processing machine 200, a self-propelled reforming processing machine 300, and a sorting machine 400 is arranged, it is at least necessary. A basic process system can be configured. This makes it easier to carry in and out the work site compared to a case where each stationary apparatus is carried into the operation site and configured as a system. In addition, work such as assembly and disassembly is greatly reduced, so it is possible to quickly configure and remove the system, and each work such as system loading, processing, and system unloading can be performed quickly. Can be shortened.
[0118]
Further, even when the work position is moved in the field, the system can be easily transported by, for example, a crane or a trailer, and the installation position can be changed as appropriate. Moreover, since the self-propelled insolubilization processing machine 200, the self-propelled solidification processing machine 300, and the like can travel on their own, when carrying in and out, for example, they can get on and off the transportation means of the trailer by themselves. Further, although the sorting machine 400 has been described as a stationary type in the present embodiment, it uses a self-propelled sieving device having a known configuration equipped with a traveling device, and the lattice member shown in FIG. The same can be said for 404. These also contribute to shortening the construction period.
[0119]
viii) Prevention of contamination
In the purification treatment of contaminated soil, if untreated contaminated soil is scattered, there is a risk of lead diffusion to the surrounding environment. Therefore, prevention of scattering of contaminated soil is an important issue. If a contaminated soil treatment system is configured by combining stationary devices, for example, the contaminated soil may spill out a little during transportation from a belt conveyor to a mixing device (such as a mixer). On the other hand, in the present embodiment, the contaminated soil put into the self-propelled insolubilization processing machine 200 is mixed with the insolubilizing agent in the self-propelled insolubilization processing machine 200. The possibility of splashing can be reduced, and the spread of contamination can be prevented.
[0120]
ix) Space saving
In the present embodiment, the system of the minimum necessary basic process can be configured by a self-propelled insolubilization processing machine 200, a self-propelled reforming processing machine 300, and a sorting machine 400. It is possible to purify contaminated soil containing, and to remove lead bullets that are the source of contamination. Thus, in this Embodiment, the contaminated soil processing system can be comprised compactly by making the contaminated soil containing a lead bullet into a process target. Therefore, even if the installation location of the system is in the mountains, for example, the exclusive area of the entire system can be reduced, so that an effective space can be used effectively.
[0121]
Note that the self-propelled insolubilizing machine 200 can perform not only the insolubilizing process but also the reforming process. Conversely, if the insolubilizing agent supply device 6 is additionally provided in the self-propelled reforming processing machine 300, the self-propelled reforming processing machine 300 can also perform the insolubilization process. From this, the self-propelled insolubilization processing machine 200 or the self-propelled reforming processing machine 300 alone serves as a self-propelled insolubilization processing machine and a self-propelled insolubilization processing machine. Of the basic system of the system, it is also possible to carry out the purification treatment part of the contaminated soil.
[0122]
[2] Modification
The purification treatment process in the basic process of the contaminated soil treatment system of the present invention is not necessarily limited to the configuration shown in FIG. 2 and can be variously modified without departing from the technical idea thereof. Here, such modified examples are sequentially illustrated with reference to FIGS. 14 and 15.
[0123]
(2-1) One modification
FIG. 14 is a side view showing the arrangement of the system of the purification treatment process portion in the basic process of a modified example of the contaminated soil treatment system of the present invention, and corresponds to FIG. In FIG. 14, for the purpose of preventing congestion, the same reference numerals are given to the same parts as those in the previous drawings, and the description thereof is omitted. The difference between this modification and the system shown in FIG. 2 is that a treated soil supply device 250 is provided between the self-propelled insolubilizing processing machine 200 and the self-propelled reforming processing machine 300. Except for this point, the other configuration is the same as that of the above-described embodiment.
[0124]
The treated soil supply device 250 receives the insolubilized treated soil from the self-propelled insolubilized processing machine 200 and supplies the insolubilized treated soil in the hopper 251 to the self-propelled reformed processing machine 300 as a storage container that temporarily stores the insolubilized treated soil. And a conveyer 252 as supply means. The hopper 251 includes an arch breaker 253. Reference numeral 254 denotes a support member that supports the transport conveyor 252. In this modification, the processing soil supply device 250 is a stationary facility, but the lower portion of the transport conveyor 252 is replaced by a vehicle body (travel device) instead of the support member 254. It is good also as what provided the hopper 251 with the arch breaker 253 in the well-known self-propelled conveyor supported by (4).
[0125]
In this modified example, in addition to the above-described one embodiment, by adding the treated soil supply device 250, the insolubilized treated soil from the self-propelled insolubilized processing machine 200 is further stirred, and the contaminated soil is made more uniform with the insolubilizing agent. It is possible to further promote the insolubilization reaction of lead. Furthermore, the movement time of the treated soil from the self-propelled insolubilized treatment machine 200 to the self-propelled reforming treatment machine 300 is secured by temporarily storing the insolubilized treated soil in the hopper 251 and securing the residence time thereof. Can do. Also by this, the effect of promoting the insolubilization reaction can be obtained.
[0126]
In the present modification, the transport conveyor 252 is a belt conveyor, but may be a screw conveyor or the like. Moreover, although the treated soil supply apparatus 250 shall be provided with the arch breaker 253 in the hopper 251, the arch breaker 253 may be omitted as long as the residence time is secured. In addition, from this point, even if the processing soil supply device 250 is not a conveyor device with the hopper 251, a simple storage container (for example, the hopper 251 may be installed alone) is used as the self-propelled insolubilization processing machine 200 and A hydraulic excavator (which may be shared with the hydraulic excavator 100 or prepared separately) is disposed as a means for supplying the processing soil to the self-propelled reforming processing machine 300, provided between the traveling reforming processing machines 300. You may do it.
[0127]
(2-2) Other modifications
FIG. 15 is a side view showing the arrangement of the system of the purification treatment process portion in the basic process of another modified example of the contaminated soil treatment system of the present invention, and is a view corresponding to FIG. In FIG. 15, the same parts as those in the previous drawings are denoted by the same reference numerals in order to prevent congestion, and the description thereof is omitted. The difference between this modification and the system shown in FIG. 2 is that the contaminated soil purification process comprising the insolubilization process and the modification process is performed by a single contaminated soil treatment machine. Except for this point, the other configuration is the same as that of the above-described embodiment.
[0128]
The contaminated soil treatment machine shown in FIG. 15 includes the main parts of the above-described self-propelled insolubilization treatment machine 200 and self-propelled reforming treatment machine 300, and the insolubilization treatment apparatus 1A and the modification treatment apparatus 1B having substantially the same configuration. Is fixed on the base frames 2A and 2B. Specifically, the insolubilization treatment apparatus 1A and the reforming treatment apparatus 1B omit the traveling device 45, and are above the main body frame 10 in the self-propelled insolubilization treatment machine 200 and the self-propelled reforming treatment machine 300 (discharge conveyor). 37).
[0129]
The base frame 2B is made of, for example, H-shaped steel or the like, and is arranged in the width direction (in the direction orthogonal to the paper surface in FIG. 15) so as to be substantially parallel to each other. It is mounted on the end portion (right end in FIG. 15) of the base frame 2B and fixed by, for example, bolts (may be welded). The base frame 2A is also made of, for example, H-shaped steel and is fastened with bolts or the like (may be welded) on the opposite end (left end in FIG. 15) of the base frame 2B. The main body frame 10 of the insolubilization processing apparatus 1A is mounted on the base frame 2A, and is fixed by, for example, bolts (may be welded).
[0130]
As in this modification, the insolubilization processing device 1A and the reforming processing device 1B that perform the insolubilization processing step and the reforming processing step, respectively, are unitized and fixed by the base frames 2A and 2B. Even if it exists, like the system of FIG. 2, a contaminated soil can be insolubilized and solidified, and the same effect can be acquired.
In FIG. 15, reference numeral 28 denotes the pump unit described in the above-described embodiment, and this pump unit 28 is omitted in the above-described embodiment and modification.
[0131]
[3] Other embodiments
Here, another embodiment of the contaminated soil treatment system of the present embodiment will be described.
FIG. 16 is a side view showing the arrangement of the system in the basic process portion of the contaminated soil treatment system of the present embodiment. However, in FIG. 16, parts that are the same as or similar to those in the previous drawings are given the same reference numerals, and descriptions thereof are omitted.
[0132]
The basic steps in the present embodiment are configured in the order of insolubilization of contaminated soil, separation of lead bullets, modification of insolubilized soil. That is, first, the insolubilized soil from the above-described self-propelled insolubilizing machine 200 is introduced into the sorting machine 400, and lead bullets are separated before the reforming process. Then, the insolubilized soil from which the lead bullets have been removed is reformed by the self-propelled reforming processing machine 300. Except for this point, the other configuration is the same as that of the above-described embodiment.
[0133]
In the self-propelled insolubilizing machine 200, as described in the embodiment, water is supplied to the contaminated soil so that the insolubilizing agent is uniformly mixed with the insolubilizing agent. That is, since the insolubilized soil discharged from the self-propelled insolubilizing machine 200 is in a slurry state with a very high water content at this point, it is easy to pass through the sieve member 404 of the sorting machine 400, and lead bullets are discharged. It can be easily separated.
[0134]
In other words, paying attention to the fact that the contaminated soil becomes slurry insolubilized soil during the insolubilization treatment, the lead bullets are separated at this point, and the insolubilized soil from which the lead bullets have been removed is reformed. However, it is possible to purify the contaminated soil and remove the contamination source. However, in this embodiment, since the lead bullets have already been removed when supplied to the self-propelled reforming processing machine 300, the additive is not necessarily as in the above-described embodiment. Even if it does not have an exothermic action, it is sufficient if it has a solidifying action. Therefore, for example, various cement-based solidifying materials such as blast furnace cement, neutral solidifying materials, gypsum-based solidifying materials, composite-based solidifying materials, bentonite, zeolite, and the like may be used. Of course, it may be a lime-based solidified material, or a material in which a powder of iron, iron oxide, aluminum or the like is mixed.
[0135]
Also in this embodiment, the same effect as that of the above-described one embodiment can be obtained. Also in the present embodiment, by appropriately combining the above-described basic treatment step with the above-described second insolubilization treatment step, the second modification treatment step, the crushing step, the water shielding treatment, etc. Needless to say, more reliable processing can be performed.
[0136]
In each of the embodiments and modifications described above, the traveling device 45 such as the self-propelled insolubilization processing machine 200 and the self-propelled reforming processing machine 300 and the traveling device 102 of the hydraulic excavator 200 are connected to an endless track crawler. Although what is called a crawler type provided with 49,101 is not necessarily restricted to this, It is good also as what is called a wheel type traveling apparatus. Moreover, although the insolubilization processing apparatus 1A, the self-propelled insolubilization processing machine 200, and the like are provided with the sieving device 3 and the turner 17, they are not necessarily required. Conversely, the sieving device 3 or the screen 17 may be provided in the reforming processing apparatus 1B, the self-propelled reforming processing machine 300, or the like. In addition, the mixing device 7 is of a paddle type, but is not limited thereto, and a mixing device having another configuration such as a device for mixing by a screw may be applied. In these cases, the same effect is obtained.
[0137]
【The invention's effect】
According to the present invention, the contaminated soil is insolubilized in a state containing lead bullets, the insolubilized treated soil is mixed with an additive having a heat generating action, and classified as a modified soil, whereby the modified soil is It becomes difficult to adhere to the eyes of the sieving member of the sorting machine and the soil is easily separated from each other, and the lead ammunition can be separated from the modified soil. Therefore, the lead in the contaminated soil can be insolubilized and lead bullets as the contamination source can be removed, and even the contaminated soil mixed with lead bullets as the contamination source can be reliably purified.
[0138]
In addition, it is also possible to insolubilize contaminated soil in a state containing lead bullets, classify the insolubilized soil, separate lead bullets, remove the lead bullets, and then modify the insolubilized soil. An effect can be obtained. In the present invention, in the insolubilization treatment step, water is supplied to the contaminated soil together with the insolubilizing agent, so that the insolubilization treatment soil becomes a slurry. In this state, the passability of the insolubilized soil through the sieve member is good, and lead bullets can be easily separated. Therefore, after removing the lead ammunition in this way, the insolubilized soil is mixed with the additive and reformed, so that even the contaminated soil mixed with the lead ammunition that is a contamination source can be reliably purified. .
[Brief description of the drawings]
FIG. 1 is a conceptual diagram schematically showing an example of a treatment process of an embodiment of a contaminated soil treatment system of the present invention.
FIG. 2 is a side view showing an arrangement of a system in a purification treatment process part composed of insolubilization treatment and reforming treatment of lead-contaminated soil in one embodiment of the contaminated soil treatment system of the present invention.
FIG. 3 is a side view showing a detailed structure in the vicinity of a sieving device and a hopper provided in a self-propelled insolubilizing machine constituting an embodiment of a contaminated soil treatment system of the present invention.
FIG. 4 is a diagram showing a detailed structure in the vicinity of the downstream side of the transport conveyor provided in the self-propelled insolubilizing machine constituting one embodiment of the contaminated soil treatment system of the present invention.
FIG. 5 is a diagram showing an example of extracting a main part related to a series of treatments in a system of a purification treatment process part consisting of insolubilization treatment and reforming treatment of lead-contaminated soil in one embodiment of a contaminated soil treatment system of the present invention. FIG.
FIG. 6 is a diagram showing a structure of a supply pipe of an insolubilizing agent supply device provided in a self-propelled insolubilization processing machine constituting an embodiment of a contaminated soil treatment system of the present invention.
FIG. 7 is a side view showing the entire structure of the sorting machine used in the classification process of the modified soil in one embodiment of the contaminated soil treatment system of the present invention.
FIG. 8 is a perspective view showing the structure of a sieving member provided in a sorting machine used in the classification process of modified soil in one embodiment of the contaminated soil treatment system of the present invention.
FIG. 9 is a side view showing the entire structure of a crushing conveyor device used in a crushing process appropriately combined with an embodiment of the contaminated soil treatment system of the present invention.
FIG. 10 is a diagram schematically illustrating an example of a state in which modified earth and sand are subjected to a water shielding treatment and are backfilled on the ground surface.
FIG. 11 is a diagram showing the weight ratio of each particle size range between contaminated soil and modified soil subjected to purification treatment.
FIG. 12 is a conceptual diagram showing a contaminated soil treatment system in a case where lead bullets are separated in advance by wet classification and the contaminated soil from which lead bullets have been removed is insolubilized as a comparative example with the present embodiment.
FIG. 13 is a diagram showing a comparison of the amount of contaminants eluted between contaminated soil and a mixture of contaminated soil with viscous soil.
FIG. 14 is a side view showing the arrangement of the system in the purification treatment process portion in a variation of the embodiment of the contaminated soil treatment system of the present invention, and corresponds to FIG.
FIG. 15 is a side view showing a system arrangement of a purification treatment process portion in another modification of the embodiment of the contaminated soil treatment system of the present invention, and is a view corresponding to FIG.
FIG. 16 is a side view showing the overall arrangement of another embodiment of the contaminated soil treatment system of the present embodiment.
[Explanation of symbols]
1A Insolubilizer
1B reformer
40 storage tank
100 Hydraulic excavator (mixing means)
200 Self-propelled insolubilizing machine (mixing means)
300 Self-propelled reforming machine (mixing means)
400 sorting machine
404 Sieve member
404a Rod-shaped member
500 Crushing conveyor device (fine graining means)

Claims (14)

A self-propelled insolubilization machine that produces insolubilized soil by supplying and mixing insolubilizers that insolubilize lead and water to contaminated soil contaminated with lead ammunition,
A self-propelled reforming treatment machine for supplying and mixing an additive material having an exothermic action to the insolubilized treatment soil generated by the self-propelled insolubilization processing machine to generate modified soil,
A contaminated soil treatment system, comprising: a sorting machine that classifies the modified soil generated by the self-propelled reforming processing machine and separates the lead bullets from the modified soil. An insolubilization treatment device for producing an insolubilization treatment soil by supplying and mixing an insolubilization agent for insolubilizing lead and water to contaminated soil mixed with lead ammunition as a contamination source, and the insolubilization treatment soil generated by the insolubilization treatment device In addition, a contaminated soil treatment machine equipped with a reforming treatment device that supplies and mixes an additive having an exothermic action to generate modified soil,
A contaminated soil treatment system, comprising: a classification machine that classifies the modified soil generated by the contaminated soil treatment machine and separates the lead bullets from the modified soil. A self-propelled insolubilization machine that produces insolubilized soil by supplying and mixing insolubilizers that insolubilize lead and water to contaminated soil contaminated with lead ammunition,
A classifying machine for classifying the insolubilized soil produced by the self-propelled insolubilizing machine and separating the lead bullets from the insolubilized soil;
The insolubilized soil from which the lead bullets have been removed by the sorting machine is provided with a self-propelled reforming machine that supplies and mixes an additive having a solidifying action to generate modified soil. Contaminated soil treatment system. 3. The contaminated soil treatment system according to claim 1 or 2, wherein the sorting machine is configured to receive fine particles by receiving the refined soil generated by the self-propelled reforming treatment machine or the contaminated soil treatment machine. Contaminated soil treatment system, characterized by being arranged in the front stage. The contaminated soil treatment system according to any one of claims 1 to 4, wherein the self-propelled reforming processing machine or the reforming processing device stores lime or a lime-based solidified material as the additive. A contaminated soil treatment system comprising: 4. The contaminated soil treatment system according to claim 3, wherein the self-propelled reforming processing machine includes a storage tank that stores cement as the additive. The contaminated soil treatment system according to any one of claims 1 to 6, wherein the sorting machine is configured by arranging a plurality of rod-like members at intervals equal to or smaller than the particle diameter of the lead bullets. A contaminated soil treatment system comprising a sieve member. The contaminated soil treatment system according to any one of claims 1 to 7, further comprising: a refining unit that receives and contaminates the contaminated soil before the self-propelled insolubilizing machine or the contaminated soil treatment machine. Contaminated soil treatment system characterized by the arrangement. The contaminated soil treatment system according to any one of claims 1 to 8, further comprising mixing means for mixing the modified earth and sand with a property of adsorbing heavy metal ions. system. Producing insolubilized soil by supplying and mixing insolubilizing agent that insolubilizes lead and water into contaminated soil mixed with lead bullets that are the source of contamination,
After generating the modified soil by supplying and mixing the additive material with exothermic action to this insolubilized treated soil,
A method for treating contaminated soil, comprising classifying the modified soil and separating the lead bullets from the modified soil. Producing insolubilized soil by supplying and mixing insolubilizing agent that insolubilizes lead and water into contaminated soil mixed with lead bullets that are the source of contamination,
After classifying the insolubilized soil, and separating the lead bullets from the insolubilized soil,
A method for treating contaminated soil, comprising: adding an additive having a solidifying action to the insolubilized treated soil separated from the lead bullets and mixing them to produce modified soil. 12. The contaminated soil treatment method according to claim 10 or 11, wherein the modified soil is mixed with earth and sand having a property of adsorbing heavy metal ions. The contaminated soil treatment method according to claim 12, wherein viscous soil is used as the earth and sand. The contaminated soil treatment method according to any one of claims 10 to 13, wherein the modified treated soil is accommodated in a hole whose inner wall surface is covered with cohesive soil, and is then shielded and covered with the covered soil. Contaminated soil treatment method.

Images