JP4250980B2 - Contaminated soil recycling system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, persistent organic pollutants (POPs) and POPs are
(1) It is difficult to decompose in the environment (hard decomposition)
(2) Easy to concentrate in living organisms through food chains (high accumulation)
(3) Easy to move over long distances and accumulate in polar regions (long-distance mobility)
(4) Harmful to human health and ecosystem (toxicity)
Since it is a chemical substance with the above properties and pollution on a global scale has been reported, it is necessary to deal with an international framework.
There are 12 types of target substances, including aldrin, dieldrin, endrin, chlordane, heptachlor, toxaphene, mirex, hexachlorobenzene, PCB, DDT, dioxins and furans.
Any one of these 12 kinds of substances or a plurality of substances are contained in the soil, and soil contamination has become a problem.
The present invention relates to soil containing POPs. After the solvent is immersed in the soil and left for a predetermined time, the used solvent is removed, and in particular, POPs such as PCB and dioxins are eluted in the solvent. Legal standard value that accepts the concentration of POPs remaining in the soil as a cement raw material (for example, in the case of PCB, graduation of treatment specified in “Special Measures Law for Promotion of Proper Treatment of Polychlorinated Biphenyl Waste”) The standard is 0.003 ppm or less, or less than 0.0005 ppm described as an environmental standard), and the soil remaining in the solvent-containing soil is further removed by a soil drying device to obtain regenerated soil. Recycling system for reusing purified soil for the purpose of using this reclaimed soil as a cement raw material It is intended.
[0002]
[Prior art]
Conventionally, soil containing POPs, such as soil containing PCB, which is one of POPs, is used by replacing part of clay constituting the raw material for producing cement clinker, and soil containing PCB is used as another clinker. There is a method in which PCB is completely decomposed by heating and detoxified by firing at 1300 ° C. to 1450 ° C. where clinker is produced in a cement kiln together with raw materials. (Patent Document 1)
[0003]
[Patent Document 1]
JP 2000-247696 A (pages 1 and 2)
[0004]
[Problems to be solved by the invention]
However, in the above conventional method, soil containing PCB, which is one of POPs, is used as an alternative component of clay constituting cement clinker without being treated. Problems with the characteristics of POPs remain,
(1) It is difficult to decompose in the environment (hard decomposition)
(2) Easy to concentrate in living organisms through food chains (high accumulation)
(3) Easy to move over long distances and accumulate in polar regions (long-distance mobility)
(4) Harmful to human health and ecosystems (toxicity)
In fact, there is a problem of handling soil containing PCB, which is one of POPs, and the soil containing PCB, which is one of POPs, directly contacts the kiln for cement, and is contaminated. To do.
[0005]
In general, the contaminated soil is temporarily stored and transported in a storage device that can be sealed, for example, before being transported to the treatment facility. At that time, the inner wall of the storage device is in direct contact with the contaminated soil to contaminate POPs. This makes it difficult to reuse the storage device.
[0006]
Moreover, PCB, which is one of POPs, is difficult to decompose as shown in (1), so the internal temperature of the kiln is also high (1450 ° C or higher), and decomposition is not complete unless incinerated. There is a high possibility that some dioxins are generated, and careful treatment such as installing a secondary combustion device is required.
In other words, when incinerating PCB, which is one of the POPs, it is necessary to thoroughly investigate and confirm the PCB decomposition capacity, PCB emission concentration, ambient environment concentration, etc. of the PCB combustion facility (kiln) in advance. It is sung in the notice of the Conservation Director (Environmental Regulation No. 141 December 22, 1972).
Also, in terms of energy, since the kiln internal temperature is high, the amount of energy used is high and the running cost is high when compared with a normal cement manufacturing process.
[0007]
Even in the kiln configuration, PCBs, which are one of POPs that are harmful to human health and ecosystems, cannot be treated with ordinary kilns, and are toxic to the treatment of exhaust gases, etc. It is necessary to deal with a detoxifying configuration.
[0008]
  An object of the present invention is to provide a recycling system in which a predetermined amount of POPs is removed from soil contaminated with POPs to obtain reclaimed soil and reused as a cement raw material. Temporary storage and transportation of contaminated soilTimeIn, POPs do not contaminate storage equipment and can suppress diffusion to the atmosphereOf contaminated soilRecycling systemThe purpose is to provide.
[0009]
[Means for Solving the Problems]
  In order to solve the above-mentioned conventional problems, the present invention is directed to a soil containing persistent organic pollutants (POPs), a solvent for dissolving POPs, a treatment tank for holding a solvent for dissolving POPs, and soil drying. Equipment and a concentration observation device capable of measuring or estimating the amount of residual organic pollutants contained in the soil, first transferring the soil containing POPs to the treatment tank, and then dissolving the POPs in the treatment tank And after leaving for a predetermined time, a part or all of the solvent that dissolves POPs in the treatment tank is withdrawn from the treatment tank and is eluted and separated into the solvent that dissolves POPs. After confirming that the concentration of the persistent organic pollutants contained in the soil of the soil is lower than the standard acceptable as a cement raw material by the concentration observation device, the soil is dried by a soil drying device. Shimete, and playback soil by removing solvent which dissolves the POPs remaining in soil containing POPs, to reuse this reproduction soil cement materialAlong with holding the soil containing the residual organic pollutant in a biodegradable packaging made of a biodegradable sheet or biodegradable film, and using a storage device for storing the biodegradable packaging, The soil containing the residual organic pollutant is taken out from the storage device and contained in the biodegradable packaging, and transferred to a treatment tank.It is characterized by this.
With this configuration, soil containing POPs can be purified simply by immersing it in a solvent, so that it can be carried out at low cost without the need for special equipment, and industrial reuse is promoted as a cement raw material, and purification processing is promoted.In addition, it is possible to prevent the work environment from being greatly contaminated by POPs together with the dust generated when the soil is transferred to the treatment tank, and the treatment proceeds more safely.
[0010]
Furthermore, it is equipped with a solvent regeneration device that separates and removes at least a part other than the solvent from the mixed solution and regenerates it as a solvent for extracting residual organic pollutants. The solvent is separated from the solvent by a solvent regeneration device, and at least a part of the separated water is mixed with the regenerated soil and used as a cement raw material. With this additional configuration, it is possible to reduce the burden on the water treatment facility necessary for discharging the water separated from the soil.
[0011]
Further, when the reclaimed soil is lacking the constituent components as the cement raw material, the lacking components are mixed to make the cement raw material. With this additional configuration, the quality when used as a cement raw material can be stabilized, and the amount employed as the raw material can be increased.
[0013]
  Also,Biodegradable packagingIncluded and retainedBy storing the persistent organic pollutants without direct contact with the storage deviceIt is characterized by being able to. With this configuration, the inner wall of the storage device is not contaminated with POPs, the storage device can be easily reused, and storage costs can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of a processing process flow. First, the soil containing persistent organic pollutants (POPs) is transferred into a treatment tank that can hold the soil and solvent. Thereafter, a solvent for dissolving POPs contained in the soil is put into the treatment tank from the solvent supply device until the soil is sufficiently immersed. This is left for a predetermined time (for example, 2 to 24 hours), and at least a part of the residual organic pollutants (POPs) dissolves in the solvent. Thereafter, the solvent is removed from the treatment tank, and the residual concentration of residual organic pollutants (POPs) contained in the soil in the treatment tank is measured or estimated. If this concentration is higher than the target reference value, the solvent is again put into the treatment tank, and the standing and the confirmation of the concentration are repeated. If the concentration is lower than the reference value, the soil in the treatment tank is dried to obtain regenerated soil. In this process, the component of this regenerated soil is confirmed, and if it is not enough, the component is added and used as a raw material for cement.
[0015]
In this treatment process, when the residual organic pollutants (POPs) -containing soil is washed with a solvent and used as a cement raw material, the constituent components (for example, silica, alumina, etc.) as the cement raw material are insufficient. The missing components are mixed and provided as a high-quality cement raw material. However, it has already been carried out while adjusting the components at the cement factory, and it can of course be delivered to the cement factory as a cement raw material when it is dried and regenerated.
[0016]
Solvents include alcoholic solvents such as ethyl alcohol, methyl alcohol, isopropyl alcohol, ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol, paraffinic solvents such as hexane, aromatic solvents such as xylene and toluene, kerosene, and Cosmo Petrotech. Petrosol, New Clean P-IS, Shal Japan's Loose, Nikko Petrochemical Co., Ltd., Nikko White, and other petroleum solvents, as well as plant extraction solvents such as soybean oil and limonene, can be used singly or in combination. . However, in order to elute the residual organic pollutants (POPs) dissolved in the water when the soil containing the residual organic pollutants (POPs) is immersed, alcohol-based solvents or plants having high compatibility with water Select the washing process so that the extraction solvent remains in the soil. For example, it is preferable to always wash with at least one of an alcohol solvent and a plant extraction solvent.
[0017]
The immersion time with the solvent depends on the elution concentration of persistent organic pollutants (POPs), but can be determined by confirming the elution characteristics using sampling of the target soil. In order to shorten the dipping time as much as possible to shorten the cleaning time, it is of course possible to stir continuously or intermittently in the treatment tank and / or slightly increase the solvent temperature in the treatment tank. However, in order to suppress heating costs and volatilization from the inside of the treatment tank and to avoid a fire, it is preferable that the solvent has a vapor pressure of 100 mmHg or less or an ignition temperature that is lower. In order to avoid ignition by static electricity, it is preferable to humidify in an environment (household) where a solvent is used.
[0018]
The immersion treatment of the contaminated soil with this solvent is not only carried out with the same solvent, but also a solvent having high solubility with respect to POPs contained in the soil among the above-mentioned solvents, such as petroleum solvents and aromatic solvents. Is used to improve the effect of separating and extracting POPs, considering the solvent remaining in the regenerated soil, and finally using an alcohol-based solvent with little residual problems, or a plant-extracting solvent such as soybean oil or limonene, etc. Of course, it can be washed once or more. At this time, for example, when washing with only an alcohol solvent or a plant extraction solvent, since the solubility is low, the number of washing is increased and the treatment cost is increased. it can.
[0019]
In addition, the moisture from the soil containing the solvent and persistent organic pollutants (POPs) is supplied and held from the solvent supply device and left for a predetermined time (for example, 2 to 24 hours). Pull out and temporarily store in the storage tank. Then, solid content and water | moisture content are isolate | separated with a distillation means and it can reproduce | regenerate as a solvent.
[0020]
On the other hand, the concentration of persistent organic pollutants (POPs) in the treatment tank is lower than the standard accepted as a cement raw material (for example, in the case of PCB, “Special Measures Law on Promotion of Proper Treatment of Polychlorinated Biphenyl Waste” However, there is no solvent in the soil containing residual organic pollutants (POPs), which is less than 0.003 ppm or less than 0.0005 ppm as the environmental standard. In order to dry the soil, the solvent is removed by using a soil drying device (for example, a boiler, a drying furnace, a hot air generator, etc.) to regenerate the soil. The reclaimed soil can be used as a cement raw material, and can be recycled as a safe cement raw material without being buried in a managed landfill for the treatment of soil containing residual organic pollutants (POPs) as industrial waste.
[0021]
Also, when considering landfill use as reclaimed soil, even if it is below the standard value, it cannot be easily reused as landfill for places close to ordinary residential areas, and must be purified to a lower concentration. It is required to be a level 1/2 to 1/10 lower than the reference value, and the purification cost tends to be high.
However, according to the present invention, by making it lower than the legal standard value accepted as a cement raw material (described above), it is safely reused efficiently in cement, and the purification of contaminated soil is promoted. This is because in the cement manufacturing process, heat treatment is performed at a high temperature of 1000 ° C. or higher, so that contamination of residual organic pollutants (POPs) at a very low concentration can be safely treated.
[0022]
In addition, the water contained in the soil is recovered at the same time as the solvent used for the extraction and separation of POPs. The extracted solvent is preferably reused as an extraction solvent after the solid content, POPs, and water are separated by a solvent regenerating apparatus such as distillation. Furthermore, it is more preferable to recycle and recycle the solvent residing in the reclaimed soil by liquefying the solvent recovered by the soil drying device through the condenser. In addition, some POPs may remain in the separated water, and after being subjected to drainage treatment there, it is discharged into sewage and natural rivers.
[0023]
In addition, it is possible to regenerate as a solvent by this solvent regeneration device, to separate and recover water originally contained in the soil, and to mix at least a part of the separated water with the regenerated soil and use it as a cement raw material. it can. At this time, the facilities relating to the wastewater treatment for the discharge of sewage and natural rivers as described above are unnecessary or can be performed with a small treatment capacity. In addition, it is assumed that the concentration of residual organic pollutants (POPs) in the reclaimed soil is slightly increased by returning water, but of course it is mixed to the extent that it is lower than the standard accepted as a cement raw material. For example, the residual organic pollutant (POPs) concentration in the separated and recovered water is measured from the concentration of residual organic pollutants (POPs) in the regenerated soil measured by the concentration observation device (for example, measured by this concentration observation device). ) Is measured and the mixing amount is determined so that it is less than the reference value.
[0024]
Persistent organic pollutants (POPs) -containing soil can also be contained in a biodegradable sheet or biodegradable film and stored in a storage device. At this time, it is possible to minimize the diffusion of the soil into the atmosphere accompanying the transfer by taking it out of the storage device and transporting it to the treatment tank while containing the soil. It is also preferable to break the biodegradable sheet or biodegradable film as finely as possible to transfer the soil containing residual organic pollutants (POPs) so that the sheet or film does not interfere with the penetration of the solvent into the soil.
[0025]
  For soil containing persistent organic pollutants (POPs), a storage device for temporarily storing the soil is provided, and the soil containing persistent organic pollutants (POPs) is biodegradable sheet or biodegradable film, etc.Biodegradable packaging consisting ofInInclusionAs a result, it is possible to prevent the persistent organic pollutants (POPs) and the inner wall of the storage device (for example, drums) from coming into direct contact with the soil containing the persistent organic pollutants (POPs). It is not contaminated by organic organic pollutants (POPs) and can be easily reused.
[0026]
In addition, as described above, by purifying the biodegradable sheet or biodegradable film together with the soil, when leaving the regenerated soil before using it as a cement raw material, the sheet or film used for the biodegradable packaging is used. Decomposition progresses, making it easier to transport regenerated soil. In addition, even when a part of the soil is used as a landfill, natural decomposition proceeds even after it is buried. It does not remain as industrial waste, and the soil tightness is improved.
[0027]
Example 1
A first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flow diagram of the contaminated soil recycling system.
[0028]
Persistent organic pollutant (POPs) -containing soil 1 is contained in a biodegradable packaging bag (biodegradable sheet or biodegradable film) 2 and stored with a storage device (for example, a drum can) 3 and a sealing lid 4. A biodegradable packaging bag (biodegradable sheet or biodegradable film) 2 is included in a storage device (for example, drum can) 3, and residual organic pollutant (POPs) -containing soil 1 is put into the storage device (for example, drum can) 3. Even if the lid is sealed, the soil 1 containing residual organic pollutants (POPs) does not adhere directly to the storage device (eg, drum can) 3.
[0029]
Residual organic pollutant (POPs) -containing soil 1 contained in a biodegradable packaging bag (biodegradable sheet or biodegradable film) 2 stored in a storage device (for example, a drum can) 3 is put into a treatment tank 5. To do.
At this time, the biodegradable wrapping bag (biodegradable sheet or biodegradable film) 2 is broken so that the soil 1 containing residual organic pollutants (POPs) is not scattered to the outside, and the treatment tank 5 is made of POPs-compatible material. Has been.
At this time, the broken biodegradable packaging bag (biodegradable sheet or biodegradable film) 2 can also be placed in the treatment tank 5. In addition, since only the surface of the biodegradable wrapping bag (biodegradable sheet or biodegradable film) 2 is in contact, it can be broken more finely and mixed with the regenerated soil 18 during the cement manufacturing process.
[0030]
By breaking the biodegradable wrapping bag (biodegradable sheet or biodegradable film) 2 into the treatment tank 5, the residual organic pollutant (POPs) -containing soil 1 is introduced and the capacity of the treatment tank 5 is increased to about 85%. Residual organic pollutants (POPs) -containing soil 1 is introduced, the top lid 6 of the treatment tank 5 is closed, and the upper sealing handle 7 is closed, and then the solvent 9 is injected into the treatment tank 5 from the solvent supply device 8 and remains. Soak soil 1 containing organic organic pollutants (POPs).
Although the injection amount of the solvent 9 is not shown, it is injected by a liquid level gauge to a position where the soil 1 containing residual organic pollutants (POPs) is completely immersed and left for a predetermined time (2 to 24 hours in the experiment by the present inventor). Experiments in the mini plant by the present inventor that the residual organic pollutants (POPs) from the soil 1 containing the residual organic pollutants (POPs) are eluted by the solvent 9 and the POPs contained in the soil can be reduced. I was able to prove it.
[0031]
After the soil 1 containing persistent organic pollutants (POPs) immersed in the solvent 9 is left for a predetermined time, the valve 14 below the treatment tank 5 is opened, and the solvent 9 and the residual organic contaminants eluted by the solvent 9 ( POPs), and further, a mixed liquid 15 composed of water or the like contained in the soil 1 containing residual organic pollutants (POPs) is drawn into the storage tank 10.
Measure the residual organic pollutants (POPs) contained in the residual organic pollutant (POPs) -containing soil 1 from the mixed solution 15 using the concentration observation device 11 to determine the concentration of the residual organic pollutants (POPs). To determine whether or not the graduation standard is acceptable as a raw material for cement.
In the present embodiment, the concentration observation device 11 is configured by a process of sampling the mixed solution 15 and replacing it with normal hexane and measuring it with a gas chromatogram. At this time, by preparing a calibration curve between the concentration of the residual organic pollutants (POPs) contained in the soil and the concentration of the mixed solution, the residual organic pollutants (POPs) remaining in the soil from the mixed solution are prepared. ) Can be estimated.
[0032]
Graduation standards for treatment specified in the Law on Special Measures for Promotion of Proper Treatment of Polychlorinated Biphenyl Waste in the case of PCB (for example, in the case of PCB) In addition, the soil 1 containing residual organic pollutants (POPs) after washing is transferred to a drying furnace (rotary kiln or the like) 19 and dried to produce reclaimed soil 18 as a raw material for cement. At this time, it is preferable to control the concentration of persistent organic pollutants (POPs) in the kiln exhaust gas.
[0033]
If the numerical value of the concentration observation device 11 is not accepted as a cement raw material, the valve 14 below the treatment tank 5 is opened, and the residual from the soil 9 containing the residual organic pollutants (POPs) eluted by the solvent 9 and the solvent 9 Water contained in the organic organic pollutant (POPs) -containing soil 1 and the residual organic pollutant (POPs) -containing soil 1 is drawn into the storage tank 10, the valve 14 below the treatment tank 5 is closed, and the solvent supply device 8 The solvent 9 is newly injected into the treatment tank 5 and the residual organic pollutant (POPs) -containing soil 1 is immersed.
Although the injection amount of the solvent 9 is not shown, it is injected by a liquid level gauge to a position where the soil 1 containing residual organic pollutants (POPs) is completely immersed and left for a predetermined time (2 to 24 hours in the experiment by the present inventor). And the process of elution of persistent organic pollutants (POPs) from the soil 1 containing the residual organic pollutants (POPs) by the solvent 9 and dissolution in the solvent 9 is repeated. Residual organic pollutants (POPs) in soil 1 containing residual organic pollutants (POPs) until they are lower than acceptable standards (for example, in the case of PCB, 0.003 ppm or 0.0005 ppm as described above) Elute into solvent 9.
[0034]
Of course, the number of elutions depends on the initial POPs concentration. In this experiment, on the basis of residual organic pollutant (POPs) content 1 of PCB (Kanechlor KC400) content of 100 mg / kg, when alcohols, especially ethanol, was used as the solvent 9, an average of 3 times There were 4 washes.
In addition, the PCB residual concentration of the residual organic pollutant (POPs) -containing soil 1 is determined by sampling the soil 1 containing the residual organic pollutant (POPs) after washing and measuring the concentration by ECD gas chromatography according to the PCB measurement method. It was measured.
[0035]
Further, the mixed liquid 15 in the storage tank 10 is sent to the distillation tower 12A, where alcohols having a low boiling point are first vaporized and liquefied by the condenser (condenser) 13A via the upper part of the distillation tower 12A, and stored in the solvent. It is stored in the tank 16A. When a certain amount of the alcohol in the distilled solvent storage tank 16A is stored, it is transported by a pump, passes through the activated carbon tower 17, and is reused.
[0036]
Next, water having a low boiling point is vaporized in the distillation column 12B, liquefied in the condenser (condenser) 13B through the upper portion of the distillation column 12B, and stored in the water storage tank 16B. When a certain amount of the distilled water in the water storage tank 16B is stored, it is transported by a pump and connected to a sewage treatment process system or mixed with the regenerated soil 18 and put into the drying furnace 19 and steam. The liquefied material is again liquefied through a condenser (condenser) 13C, then passed through the activated carbon tower 17, and then transported together with the regenerated soil 18 dried in the drying furnace 19, and transported as a cement raw material to the cement manufacturing process. Is done.
[0037]
The concentrated residual organic pollutants (POPs) separated by the distillation tower 12B are stored and managed in the residual organic pollutant storage tank 16C together with other solid contents such as minerals such as sand, calcium and magnesium.
[0038]
The solvent 9 is injected into the treatment tank 5 at least once until the numerical value of the concentration observation device 11 is lower than a standard acceptable as a cement raw material (for example, 0.003 ppm in the case of PCB). Can be repeatedly used after being distilled and purified in the distillation column 12A.
[0039]
On the other hand, the residual organic pollutant (POPs) -containing soil 1 after washing whose numerical value of the concentration observation device 11 is lower than the standard accepted as a cement raw material by the solvent 9 (for example, 0.003 ppm in the case of PCB). The solvent 9 and water slightly remain, and soil 1 containing residual organic pollutants (POPs) after washing in a drying furnace (rotary kiln or the like) 19 as a soil drying device for volatilizing the solvent 9 remaining in the soil And dried to produce reclaimed soil 18 as a raw material for cement.
[0040]
(Example 2)
A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a flowchart 2 of the contaminated soil recycling system, and the configuration of the treatment tank of FIG. 2 is different from that of FIG.
[0041]
In the soil 1 containing residual organic pollutants (POPs) after washing, the value of the concentration observation device 11 is lower than the standard accepted as a cement raw material by the solvent 9 (for example, 0.003 ppm in the case of PCB). Residual organic pollutants (POPs) -containing soil after washing by a hot air generator 20 (for example, a boiler, a chiller, etc.) provided in the treatment tank 5 via a pipe line, with some residual solvent 9 and water 1 is dried in the treatment tank 5 without moving to the outside, and the regenerated soil 18 which is a raw material of cement is manufactured.
In this embodiment, the concentration observation apparatus 11 is implemented by sampling the regenerated soil 18 and extracting it with normal hexane and measuring it with a gas chromatogram.
[0042]
(Example 3)
Example 3 relates to a solvent regenerating apparatus. Although not shown, in FIGS. 2 and 3, the solvent regenerating apparatus, that is, a distillation column 12A for purifying the solvent 9, a condenser (condenser) 13A, a solvent storage tank 16A, and transported by a pump. It is possible to lower the boiling point by making the pipes that pass through the activated carbon tower 17 and reused, the distillation tower 12B for purifying water, the condenser (condenser) 13B, and the pump at the rear stage of the water storage tank 16B to be in a vacuum state. is there.
[0043]
Since the boiling point can be lowered and the temperature in the distillation column can be lowered by making the vacuum state, it goes without saying that the running cost of the heat source can be reduced and the similar solvent 9 can be reused.
[0044]
In this example, the case where an alcohol solvent was used was shown. However, when normal hexane was used, for example, as shown in Example 1, it was not necessary to re-extract the mixed solution 15 with hexane, and sampling was performed. Gas chromatographic measurement can be carried out only by removing the solid content from the liquid mixture 15. In addition, when a plurality of solvents are used, it goes without saying that a plurality of distillation columns 12A for regeneration are arranged to facilitate maintenance. Moreover, in each Example, it is not necessary to complete completely for regenerated soil, and it may be naturally dried by leaving it alone.
[0045]
【The invention's effect】
  As described above, according to the present invention, the soil containing residual organic pollutants (POPs) is soaked in a solvent, and the standard of accepting the value of the concentration observation device as a cement raw material (for example, 0.003 ppm or less in the case of PCB) After that, it can be dried to obtain a safe reclaimed soil, which can be used as a raw material for cement, and can be handed over to a cement manufacturing company without the need for landfill of management type as industrial waste. .
Further, since the solvent can be repeatedly used in a solvent regenerating apparatus (distillation / purification), the cost of the solvent can be kept low.
Furthermore, since the storage device includes the soil containing persistent organic pollutants (POPs) in the biodegradable sheet or biodegradable film, the soil containing the residual organic pollutants (POPs) does not contact the storage device directly. InAccordingContamination can be prevented.
[Brief description of the drawings]
FIG. 1 is a processing flow diagram of a contaminated soil according to an embodiment of the present invention.
[Fig. 2] Flow chart of the contaminated soil recycling system 1
[Fig. 3] Flow diagram of the contaminated soil recycling system 2
[Explanation of symbols]
  1. Soil containing persistent organic pollutants (POPs)
  2 ... Biodegradable packaging (biodegradable sheet or biodegradable film)
  3 ... Storage device
  4 ... Lid
  5 ... Processing tank
  6 ... Upper lid
  7 ... Sealing handle
  8 ... Solvent supply device
  9 ... Solvent
  10 ... Reservoir
  11 ... Concentration observation device
  12A ... Distillation tower
  12B ... Distillation tower
  13A ... Condenser (condenser)
  13B ... Condenser
  13C ... Condenser
  14 ... Valve
  15 ... mixed liquid
  16A ... Solvent storage tank
  16B ... Water storage tank
  16C ... Persistent organic pollutant storage tank
  17 ... Activated carbon tower
  18 ... Regenerated soil
  19 ... drying oven
  20 ... Hot air generator

Claims (4)

A solvent that dissolves the persistent organic pollutant with respect to the soil containing the persistent organic pollutant, a treatment tank that holds the soil and the solvent, and a soil drying device that volatilizes the solvent contained in the soil. , Equipped with a concentration observation device that can measure or estimate the amount of persistent organic pollutants contained in the soil,
First, the soil is transferred to the treatment tank, and then the solvent is poured into the treatment tank and left for a predetermined time. Then, at least a part of the solvent in the treatment tank is extracted, and together with the solvent, the solvent At least one cleaning step for leaching and separating residual organic pollutants was performed, and the concentration of the residual organic pollutants contained in the soil was confirmed to be lower than the standard accepted as a cement raw material by the concentration monitoring device. Thereafter, the solvent remaining in the soil is further removed by the soil drying device to regenerate the soil, and the regenerated soil is used as a cement raw material, and the soil containing the residual organic pollutant is produced. It is contained and held in a biodegradable packaging made of a degradable sheet or biodegradable film, and a storage device for storing the biodegradable packaging is used. From the tube device while still included in the biodegradable packaging, the persistent organic pollutants recycling system contaminated soil is characterized by taking out the soil containing transferred to the processing tank.   It further comprises a solvent regenerator that regenerates as a solvent that separates and removes at least a part other than the solvent from the mixed solution to extract residual organic pollutants, and after the soil is immersed, the water separated and recovered from the soil together with the solvent 2. The contaminated soil recycling system according to claim 1, wherein the solvent regeneration apparatus separates the solvent from the solvent and mixes at least a part of the separated water with the regenerated soil to be used as a cement raw material.   3. The contaminated soil recycling system according to claim 1, wherein when the regenerated soil is lacking in constituent components as a cement raw material, the lacking components are mixed into a cement raw material. By maintaining encompass the soil containing the persistent organic pollutants to the biodegradable packaging, wherein said persistent organic pollutants, characterized in that can be stored without contacting the storage device directly Item 1. A contaminated soil recycling system according to item 1 .

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