JP5062579B1 - Contaminated soil treatment system containing radioactive material. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a treatment system for contaminated soil containing a radioactive substance capable of completely removing the radioactive substance from the contaminated soil containing a harmful radioactive substance.
SOLUTION: Using alkaline warm water as washing water for contaminated soil containing radioactive substances, adding a radioactive element adsorbent to a part of the washing process of contaminated soil, solidification from soil washing water containing solids adsorbing radioactive elements. through the liquid separation device to separate the sludge is a solid comprising a completely harmless water purification and hazardous radioactive materials, solids containing hazardous radioactive substances are completely radiation by enclosing the radiation shielding capsule A contaminated soil treatment system that contains radioactive substances that prevent leakage and the recycled water that is completely detoxified constitutes a circulation block circuit as wash water for contaminated soil.
[Selection] Figure 1

Description

The present invention relates to treatment of contaminated soil treatment containing radioactive substances, and solidified by solid-liquid separation of only soil containing harmful radioactive substances from washing water using a high-performance washing apparatus and radioactive element absorbent. solids containing hazardous radioactive materials, recycled together to prevent leakage to the outside and sealed in radiation shielding capsule, the cleaning process of contaminated soil containing radioactive materials as wash water of the separated wash water again contaminated soil The present invention relates to a contaminated soil treatment system containing radioactive substances that can be used.

Conventionally, measures for detoxifying soil contaminated with oil and heavy metals in a contaminated area safely and reliably, quickly and in large quantities at low cost have been studied .
It is estimated that 500 million tons of contaminated soil from the scattering of a large amount of radioactive pollutants in the Great East Japan Earthquake that occurred on March 11, 2011.
In general, as a method of treating contaminated soil, there is a method of excavating contaminated soil, removing it out of the contaminated area, and carrying in another fresh soil to replace it. Contamination can be removed with certainty, but when the contaminated soil contains contaminated soil containing radioactive substances, there are problems in the prevention of radioactive leaks during transportation of the removed soil, as well as acceptance and safety issues.

In addition, as a countermeasure method for the soil contamination problem, there is a method (for example, see Patent Document 1) in which the soil is washed with chemicals or water, the contaminants are extracted and removed, and the washed soil is backfilled in the site. is, in order to increase the removal rate of pollutants, must be large-scale cleaning equipment, costly to the control equipment, the contaminated soil containing radioactive material would not be corresponds.

  Moreover, with the above-described cleaning equipment, not only a sufficient effect cannot be obtained, but it is difficult to reuse the contaminated soil after cleaning, and it has been forced to treat it as industrial waste that has been cleaned. In addition, since chemicals used as cleaning liquids and cleaning agents are generally expensive, using them for the treatment of heavy metal-containing soils that must be treated in large quantities can be costly and economically problematic. It was. Further, in the conventional technique such as the cleaning technique in the above-mentioned Patent Document 1, the cleaning water used for cleaning cannot be “reused”. On the other hand, the effect is not expected so much, and the response to contaminated soil containing radioactive materials is not expected at all.

  Therefore, the present inventor uses a separate, high-performance, small-space soil washing facility to wash soil contaminated with harmful substances using peridotite, and to wash and adsorb heavy metals to solidify by insolubilization. Invented and applied for a pollutant insolubilizing / purifying agent that can be completely detoxified and reused (see Patent Documents 2 and 3). Further, a treatment method for purifying and detoxifying water after use for washing and removing harmful substances in contaminated soil and washing it has been invented (see Patent Document 3). Furthermore, an adsorbent using seaweed has been invented and has already been filed. This has the effect of coagulating and precipitating 90% or more of heavy metals by mixing certain baked seaweed charcoal and shell coagulating precipitants.

  JP 2004-57953 A   JP 2007-283279 A   JP 2011-111617 A

Therefore, the present invention utilizes the above-described prior art, further improves, and cleans only soil containing harmful radioactive substances using a high-performance washing device and radioactive element absorbent for contaminated soil containing radioactive substances. from water to solid-liquid separation, solids containing hazardous radioactive substances are solidified serves to prevent leakage to the outside and sealed in radiation shielding capsule, separated wash water as wash water again contaminated soil providing contaminated soil processing system including a radioactive substance that can be reused in the cleaning process of contaminated soil containing radioactive materials is an object.

The invention described in claim 1 uses alkaline warm water for cleaning contaminated soil, and continuously cleans and grinds the contaminated soil. Contamination by the first step of using a gravity-type cleaning device that peels off objects from the surface of soil particles, or a forced-polishing type cleaning device that forcibly separates harmful contaminants from the surface of soil particles by friction, and contamination by a waste classifier A second step of removing waste wood, dust, pumice, etc. in the soil, and classifying and discharging the soil particles from which harmful substances have been separated in the first step to a second grade grain soil group;

  Continuous silt that separates the residual water containing contaminated components from the second step (hereinafter simply referred to as “polluted residual water”) into a solid and contaminated residual water by causing a high-speed tornado-like rotating water stream to wash away high-concentration contaminated soil The third step of discharging into the classification device and discharging the settled fine grained soil and the contaminated residual water separated by the third step are charged into the stirring and cleaning device and further washed to obtain solids and contaminated residues as precipitates. A fourth step of separating into water and returning the precipitate to the third step for reprocessing, and sending the contaminated residual water to the next agglomeration solid-liquid separation device;

The radioactive element adsorbent ( see Japanese Patent Application No. 2011-106698) is forcibly added to the contaminated residual water separated in the fourth step, and the mixed agitation solid / liquid separation apparatus continuously performs the stirring from the contaminated residual water. The 5th step of adsorbing radioactive material, and the radioactive element adsorbent that has adsorbed the radioactive material in the 5th step and the centrifuge that separates residual water, remove the sludge containing harmful radioactive material and completely remove the harmful material. Including a sixth step of separating into detoxified purified water, and the cleaning water completely detoxified by the sixth step is returned as cleaning water in the first step and the third step to form a cleaning circuit and the sixth step the sludge containing hazardous radioactive material separated by further drying and solidifying KatachiSei to solid dosage having a radiation shielding function mainly containing peridotite (e.g., "earth protection Tar is a contaminated soil processing system including a radioactive substance, characterized in that by coating the surface by (registered trademark) "performing radiation shielding process.

Then, The invention described in 2 claims a shall be used to hold the temperature of the alkaline hot water to be used in the first step to 20 ° C. to 60 ° C., the invention described in claim 3 The temperature of the washing water used in the fifth step is maintained at 20 ° C. to 50 ° C. for use.

The invention described in claim 4, solid with radiation shielding function mainly further drying and solidifying KatachiSei to peridotite sludge containing hazardous radioactive material separated in the sixth step A harmful radioactive substance dried and solidified is sealed in a capsule composed of an agent to prevent leakage and release of radiation to the outside.

According to the present invention, by using alkaline warm water for cleaning contaminated soil, the ability to peel off radioactive substances attached to the contaminated soil is dramatically improved. Further , by forcibly introducing the radioactive element absorbent invented by the inventor into the agitation / aggregation solid-liquid separation apparatus in the fifth step, the washing water centrifuged in the sixth step of the treatment step is almost contaminated with radioactive substances. It can be reused as normal washing water.

The sludge containing hazardous radioactive material separated as solids, separately, further dried and solidified KatachiSei has been outside of the radiation by enclosing the process placed on the configured capsules in solid agent having a radiation shielding function It is possible to prevent leakage to the
Thus, massive radioactive contaminated soil that has been turned in the first step does not require a huge area also place to store capsule for shielding to be concentrated to the number percent of solids, prior to the disaster recovery work It has an excellent effect that can quickly remove soil containing harmful radioactive substances.

Also, since polluted soil treatment system of the present invention, Runode can be continuously processed to ensure a large amount of contaminated soil in a small space, the in addition to the effects of the present invention, it is possible to process low cost contaminated soil This can greatly contribute to the reduction of processing costs.

Furthermore, in the continuous treatment method using the adsorptive coagulant of the present invention, off-site drainage treatment is unnecessary, and the radioactive material is hardly attached to the soil discharged from the classification device during the treatment, and the backfilling soil also cut with reduced off-site emissions and hazardous waste.

  It is explanatory drawing of the contaminated soil processing system containing the radioactive substance of this invention.

  Hereinafter, although the contaminated soil processing system containing the radioactive substance of this invention is demonstrated, this invention is not limited to these Examples. Moreover, in the following description, about the member, site | part, and structure which have the same function, the same code | symbol may be attached | subjected and description may be abbreviate | omitted.

Hereinafter, an embodiment of a contaminated soil treatment system containing a radioactive substance of the present invention will be described based on the system explanatory diagram of FIG.
Contaminated soil containing radioactive material in the contaminated area (hereinafter simply referred to as “contaminated soil”) A is excavated from the contaminated area with a mechanical force such as a shovel car to separate concrigala, wood pieces, plastic, iron pieces, etc. 20 [deg.] C. supplied to the soil treatment plant by a transporting device, etc., put into the forced cleaning device 1 as the first processing step (hereinafter simply referred to as "the first step"), and supplied from the alkaline hot water manufacturing machine B Mixing with alkaline washing water b of -60 ° C., preferably 50 ° C., continuously crushing and crushing to remove harmful pollutants from the surface of the contaminated soil particles. As the alkaline aqueous solution, for example, a sodium hydroxide (caustic soda) aqueous solution having a pH of about 8 to 12 is used. However, if alkaline warm water is used, the cleaning effect is improved.

The alkaline concentration is adjusted according to the soil quality of the contaminated soil. Then, the forced-polishing washing apparatus 1, the cleaning grinding unit and for performing the sliding crushed and crumpling crush continuously, gravity cleaning apparatus used for separating the toxic contaminants by gravity impact action from the surface of the contaminated soil particles However, in this embodiment, a known cleaning device is used as a hurricane cleaning and grinding device.

Here, the soil 1a from which harmful pollutants have been peeled off from the surface of the contaminated soil particles is supplied to the waste collection and classification device 2 which is the second step to remove wood chips, garbage, pumice, etc. in the contaminated soil. Dispose as Waste C. The soil particles which harmful substances are peeled off in the first step the grain soil groups plurality classes, for example 40mm~20mm and two groups 20Mm～5mm D, is discharged is classified into E. A commercially available product is also used for the dust collection and classification device 2 used in the second step.

Residual water containing pollutants and pollutants in the second step (hereinafter simply referred to as “polluted residual water”) 2a causes a high-speed tornado-like rotating water stream to wash highly contaminated soil, To the third step of separation. In the third step, for example, the continuous silt classifier 3 is used, and the precipitated particles (5 mm to 7 μm) are classified and discharged as fine grain soil F. Then, this contaminated residual water 3a is sent to the stirring and washing device 4 in the fourth process, which is the next processing step, and further washed and separated into a solid substance as the precipitate R and the contaminated residual water 4a. R is returned to the above-described continuous silt classifier 3 in the third step and is reprocessed. A commercially available modified thickener microbubble stirrer is used for the stirring and washing apparatus 4 used in the fourth step.

The contaminated residual water 4a separated in the fourth step is sent to the stirring coagulation solid-liquid separation device 5 which is the fifth step in which mixing and stirring are continuously performed. As this stirring coagulation solid-liquid separation device 5, a commercially available hydromixer coagulation solid-liquid separation device is used, and Earth Protector (registered trademark) P, which is a radioactive element adsorbent separately developed by the present inventor in this fifth step. By forcibly supplying, the radioactive material can be absorbed from the contaminated residual water and adsorbed and retained.

  The earth protector P is a contaminant adsorbent mainly composed of peridotite, and adsorbs and holds fine contaminants from contaminated residual water. Therefore, in order to separate the earth protector that adsorbs and retains fine contaminants and the residual water, the solid matter containing both and the residual water 5a are sent to the centrifuge 6 which is the next sixth step, and the radioactive material is removed. It is separated into the dewatered sludge G contained and the purified water W that has been detoxified by removing radioactive substances. As the centrifuge used in the sixth step, a commercially available screw decanter type centrifuge is used.

The detoxified purified water W can be returned to the alkaline hot water washing machine B for the first step or stored in the purified water tank T and reused as washing water for the continuous silt classifier 3. I can do it. The dewatered sludge G is further dried and solidified KatachiSei coated with earth protector is a solid agent has a radioactivity shielding 蔽 function mainly of peridotite, or constitute a capsule enclosed therein By doing so, it is possible to perform the encapsulation process 7 that completely prevents radiation leakage.

  In addition, since the particle | grain soil discharged | emitted by classification in the 2nd process and the 3rd process has almost peeled off the particle | grain surface contaminant, it can be utilized also as soil for backfilling according to an environment.

DESCRIPTION OF SYMBOLS 1 ... Forced polishing type washing | cleaning apparatus 2 ... Dust collection classification apparatus 3 ... Continuous silt classification apparatus 4 ... Stirring washing apparatus 5 ... Stirring aggregation solid-liquid separation apparatus 6 ... Centrifugal separator 7・ ・ ・ Radioactive substance encapsulation treatment A ・ ・ ・ Contaminated soil B ・ ・ ・ Alkaline hot water production machine C ・ ・ ・ Industrial waste D ・ ・ ・ Coarse grain E ・ ・ ・ Medium grain soil F ・ ・ ・ Fine grain soil P ... Radioactive material adsorbent R ... Precipitate T ... Water purification tank (harmless)
G ... Dehydrated sludge W ... Purified water (harmless)

Claims (4)

Using an alkaline hot water for cleaning contaminated soil, peeling the harmful contaminants from the surface of soil particles by gravity impact action to crush kneading contaminated soil and ground crushed from the cleaning grinding unit and polluted soil particles continuously performed gravity A first step of using a water-based cleaning device or a forced-polishing cleaning device that forcibly separates harmful pollutants from the surface of soil particles by friction;
A second step of removing waste wood, garbage, pumice, and the like in the contaminated soil by the dust collection classifier, and classifying and discharging the soil particles from which harmful substances have been separated in the first step to a plurality of grades of soil groups;
Continuous silt that separates the residual water containing contaminated components from the second step (hereinafter simply referred to as “polluted residual water”) into a solid and contaminated residual water by causing a high-speed tornado-like rotating water stream to wash away high-concentration contaminated soil A third step of putting into a classifier and classifying and discharging the settled fine-grained soil;
The contaminated residual water separated in the third step is put into a stirring and washing apparatus, further washed and separated into a solid matter as a precipitate and contaminated residual water, and the precipitate is returned to the third step again. A fourth step of reprocessing and sending the contaminated residual water to the next agglomeration solid-liquid separator;
Separated by the fourth step, the fed contaminant residual force the radioactive element adsorbent was added to water, stirred flocculation solid-liquid separator for performing mixing and stirring continuously, the radioactive materials from contaminated residual water adsorption And a fifth step
The centrifugal separator for separating radioactive element adsorbent residual water adsorbed radioactive material by the fifth step, separated into a is sludge harmless removed completely harmful substances containing harmful radioactive material purified water Including the sixth step,
Contaminated soil treatment system including a radioactive substance purified water that is completely harmless by the sixth step is characterized by configuring the cleaning circulation path is fed back as washing water of the first step or the third step.   The contaminated soil treatment system containing a radioactive substance according to claim 1, wherein the temperature of the alkaline hot water used in the first step is kept at 20 to 60 ° C. Pollution containing radioactive substances according to claim 1, wherein the use maintains the temperature of the washing water used for the fifth step of performing by introducing radioactive elements adsorbent 20 ° C. to 50 ° C. Soil treatment system. Sludge containing hazardous radioactive material separated by said sixth step is encapsulated in further dried and solidified KatachiSei to constituted by a solid material having a radiation shielding function mainly containing peridotite capsule contaminated soil treatment system including a radioactive substance according to claim 1, 2 or 3, wherein the.

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