JP2005040776A - Technique for purifying contaminated soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for purifying contaminated soil simply, effectively and cheaply in situ even the contaminated soil having a large area. <P>SOLUTION: A technique for purifying the contaminated soil includes an excavation process for excavating a required depth from the surface of the contaminated soil based on the investigation of soil and making coarse massive excavated soil; a purification adjustment material mixing process for spraying a purification adjustment material by a required weight ratio to the amount of excavated soil, crushing fine-granularly and mixing, and making purification adjustment soil; and a sprinkling preparation process for sprinkling and penetrating the purification adjustment material including an artificial zeolite powder having an average particle size of 100 μm or smaller, a specific surface area of 100 m<SP>2</SP>/g or more and a base exchange capacity (meq/100g) of 200 mg or more, and purified water mixed and dispersed in the ratio of the artificial zeolite powder to water of 5 to 15% by weight ratio over the whole surface of the purification adjustment soil, and preparing the soil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Detailed Description of the Invention

Industrial application fields

  The present invention relates to a method for purifying contaminated soil in which the contaminated soil is maintained at a current position easily and inexpensively, and the effect of preventing contamination is maintained over a long period of time.

Conventional technology

  In Japan, along with economic development and the expansion of the scale of industry, wastewater or waste, including large amounts of smoke, has been discharged and discarded. As a result, the entire environment, including air, water, and soil, is extremely polluted, and in particular, chemical substances, organic compounds, or volatile organic compounds are discharged and disposed of with the development of the chemical industry. There is a high risk of hindering the active function, which has already caused many health hazards, and countermeasures for this have become socially urgent issues.

  And the important thing is that air and water pollution has a relatively natural purification action, but in the case of soil, there is no room for self-cleaning action, so once pollution starts, it continues to accumulate indefinitely, As a result, groundwater contamination accidents have been invited in various locations.

As a means for purifying such contaminated soil, there has conventionally been known a land substituting purification means and an in-situ purification means for excavating and discharging the contaminated soil, and then carrying back to the land. In addition, the contaminated soil is excavated and carried out, removed from the pollutant by high-temperature firing or chemical agents, purified, and then re-imported and backfilled.
In addition, as a means for purifying the current position, a suction well is installed in the unsaturated zone above the groundwater surface by boring, and the pressure is reduced by a vacuum pump, blower, etc., and the vapor of the pollutant is sucked and removed by adsorption with activated carbon or oxidative decomposition with ultraviolet rays. Soil gas suction method, and after drilling into multiple circular shapes, solidified / insolubilized method of insolubilizing and insolubilizing special cement, etc. into the soil, contaminated soil by heavy fuel oil A flowing into sodium silicate aqueous solution Soil washing method to be washed, reduction treatment of hexavalent chromium with iron powder or reduction insolubilization treatment of hexavalent chromium with ferrous sulfate, etc. For example, an electrical separation method is known in which an electrode is inserted into the electrode and an ionic contaminant is transferred and then decomposed.

  However, even in these soil remediation methods, the soil-based method is extremely difficult because the contamination of the entire environment has already progressed, and securing of clean soil itself is extremely limited and the supply amount is restricted. Furthermore, even in the method of excavating and purifying contaminated soil, as the urbanization progresses in recent years, the place where the purification treatment of these contaminated soil is limited to remote areas, the removal, purification treatment, In addition to enormous costs for re-loading, purification by high-temperature baking or chemical treatment significantly changes the soil composition, resulting in many restrictions on reuse.

  In addition, the known in-situ purification means are not only very large in the scale of the purification work, but also require highly specialized technology together with special equipment for their implementation, so the cost of the purification process is extremely expensive. Even if the specified contaminated soil area is purified at the original location, groundwater containing pollutants in the adjacent contaminated soil freely penetrates and moves into the soil basement. The problem of being recontaminated by groundwater is inherent.

  As a result of conducting extensive research in view of such problems, the inventor has recently achieved physical adsorptivity, moisture absorption and water absorption by a large amount of fine pores in a wide range of particle sizes by alkali pretreatment and high pressure and high temperature treatment using coal ash as a raw material. As well as moisture retention or moisture retention in the micropores, and maintaining moisture conditioning to release and release water according to the degree of dryness, and to maintain basic catalytic action and strong base substitution to the catalytic action The present invention has been clarified that it is possible to adsorb, fix, or decompose the ionized heavy metals, inorganic compounds, organic compounds and other pollutants by imparting water and to exert a purification action over a long period of time. It came to.

Problems to be solved by the invention

  It is an object of the present invention to provide a method for purifying contaminated soil, which can purify contaminated soil over a wide area in a simple, efficient and inexpensive manner, and can exhibit a purification effect over a long period of time.

Means for solving the problem

The technical means used by the present invention in order to solve the above-mentioned problem is that the appropriate position of the contaminated soil is bored, a soil survey is performed to determine the contamination state, the contamination distribution and the soil porosity, and the Based on the soil survey, the contaminated soil solidified over the required depth range from the contaminated soil surface is excavated to form a rough lump excavated soil, and the required weight for the amount of excavated soil Applying the purification adjustment material at a ratio and crushing and mixing into fine particles to give the purification adjustment soil, the purification adjustment material mixing process is performed, and the contact surface area ratio to the contaminant is extremely large, and the contamination is positive In order to adsorb or absorb moisture, absorb water, and to penetrate and mix sufficiently in the contaminated soil gap, the average particle size is 100 μm or less, and the contaminants are adsorbed, absorbed or absorbed efficiently. Ku is hygroscopic, with a large so-called the ratio surface of the water capacity of at least 100 m 2 / ^g or more,且Ya chucking its inherently addition to catalysis of holding by applying a strong base substitution contaminants by Shimuru An artificial zeolite powder having a base substitution capacity (meq / 100 g) of 200 mg or more is used as a purification adjusting material so that the adsorption decomposition is performed.

  Thus, the contact between the contaminants in the contaminated soil and the purification adjustment material is enhanced over the entire surface of the purification adjustment soil thus formed to promote adsorption fixation or adsorption decomposition, and the penetration of the purification adjustment material into the soil deeper than the bottom of the excavated soil. In order to prevent contamination from spreading deeply into the soil, a water spray leveling step is performed in which purified water mixed with 5 to 15% by weight of artificial zeolite powder is sprinkled and permeated to form water. Exist.

In addition, the pollutants that contaminate contaminated soils are diverse, including heavy metals, inorganic compounds, and organic compounds. The ionization modes of these pollutants in the contaminated soil are also different, and the state of contamination varies depending on the contaminated soil composition. On the other hand, a large amount of pollutants tend to adhere to fine granular soils such as clay and humus.
Therefore, in order to improve the contact between the pollutant and the purification control material for the purification of the pollution, the purification adjustment water is made to permeate the entire surface of the purification adjustment soil to purify the pollutant adhering to the fine soil using a cohesive discrete action. In order to promote adsorption fixation or adsorption decomposition with the adjusting material, a structure in which calcium sulfate is mixed and dispersed at a ratio of 0.5 to 5.0% by weight, and reduction of heavy metals or inorganic compounds to achieve adsorption fixation or In order to enhance the adsorptive decomposability, ferrous sulfate is mixed and dispersed in the purified water at a ratio of 0.5 to 5.0% by weight.

Action

Since the present invention has the above-described configuration and the soil survey is performed prior to the implementation of the present invention, it is possible to determine the type and concentration of the pollutant and the contamination distribution or the porosity of the soil. Excavation from the soil surface to the depth of the contaminated soil to be purified to form a rough lump excavated soil, so even relatively solid, contaminated soil such as backhoes and excavators, etc. Drilling can be done efficiently with agricultural machinery, etc., and the weight ratio to the amount of excavated soil, the average particle size is 100 μm or less, the specific surface area is 100 m ² / g or more, and the base substitution capacity (meq / 100 g) Since the purification adjustment material consisting of 200 mg or more of artificial zeolite powder is sprayed, and it is crushed and mixed into fine granules to form the purification adjustment soil, the excavated soil and the purification adjustment material are easy and homogeneous. In addition, the soil can be continuously processed by a civil engineering machine such as a stabilizer or an agricultural machine such as a drive harrow or a rotary sower.

Since the artificial zeolite powder as a purification adjustment material mixed in the purification adjustment soil is a fine particle having an average particle size of 100 μm or less, the contact surface area ratio relating to adsorption, moisture absorption and water absorption of pollutants is extremely large and active. Adsorption, moisture absorption and water absorption, as well as adsorption, moisture absorption and water absorption capacity associated with a huge amount of fine pores are so large that the so-called specific surface area is 100 m ² / g or more, so adsorption, moisture absorption and water absorption are efficiently performed. Since the artificial zeolite powder essentially retains catalytic action and has a strong base substitution capacity (meq / 100 g) of 200 mg or more, heavy metals and inorganic compounds are strongly adsorbed and fixed. The compounds are adsorbed and decomposed for purification.

Furthermore, since the purified water in which artificial zeolite powder is mixed and dispersed at 5 to 15% by weight with respect to water is sprinkled and infiltrated at a required weight ratio over the entire surface of the purified adjustment soil, the leveling is performed. In addition, the contact between the pollutant in the purification-adjusted soil and the artificial zeolite powder is remarkably increased, and the adsorbing and fixing of the pollutant is further promoted, and the purification-adjusted soil is compacted.
In addition, by making permeation promotion holes with the required pore diameter and depth at equal intervals in the soil deeper than the bottom of the excavated soil, the purified water that permeates and permeates the surface of the purification adjusted soil It penetrates and diffuses deeper into uncontaminated soil or slightly contaminated soil, thereby preventing increase of contamination and contamination diffusion. In addition, since the purification regulator mixed or osmotically diffused with contaminated soil retains its shape retention and adsorption function for a long period of time, it can also be adsorbed or adsorbed and decomposed during infiltration of contaminated groundwater. It is done.

  In addition, by mixing and dispersing calcium sulfate in the purified water in a proportion of 0.5 to 5.0%, it is possible to improve the ion exchange by lowering the pH value and to coagulate and contaminate finely polluted soil due to the cohesive discrete action. The pollutants are easily adsorbed and fixed or decomposed, and ferrous sulfate is mixed and dispersed in the purified water at a weight ratio of 0.5 to 5.0%, so that the pollutants are reduced and adsorbed and fixed. Or since it is adsorbed and decomposed, the purification is remarkably improved.

  In the following, the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of the excavation process, and the excavation process 1 is a contamination concentration and distribution in a soil survey prior to the implementation of the present invention. The soil depth of the contaminated soil 1A is generally a volcanic ash clay or sandy clay layer in the lower layer of the top soil, and further in the lower layer There are sandy gravel mixed with clay, and the lower layer is composed of sandy clay. Concerning the pollution distribution, the topsoil has the highest pollution concentration, and gradually decreases toward the lower layer, and the contamination level increases again in the lower layer, and the topsoil is contaminated at a high concentration but gradually decreases toward the lower layer. It is roughly divided into a case where only the topsoil is contaminated, and the like. Therefore, the depth to be excavated is determined based on the pollution distribution and the environmental standards for soil contamination.

And this excavation process 1 is excavated soil 1B which excavated contaminated soil 1A from purification adjustment material 2A by excavating once solidified and polluted contaminated soil 1A into a rough lump and excavating soil 1B. To facilitate homogeneous mixing.
In the excavation process 1, when the excavation depth is sufficiently deep, it is preferable to use a civil engineering machine such as a backhoe or an excavator. However, when excavation is relatively shallow within about 50 cm, a deep tillage rotary or the like is used. The use of agricultural machinery is advantageous.

Thus, after the contaminated soil 1A is excavated to the required depth to become the excavated soil 1B, the purification adjusting material mixing step 2 is performed as shown in FIG. This purification adjustment material mixing step 2 is a weight required for the amount of excavated soil of the excavated soil 1B for the admixture 2A for purifying the contaminated soil 1A by adsorbing and fixing or decomposing the contaminants of the contaminated soil 1A. To spread and mix evenly in proportions.
In this purification adjustment material mixing step 2, the purification adjustment material 2A to be sprinkled and mixed on the excavated soil 1B has a very large contact surface area ratio so that it can come into contact with the contamination of the contaminated soil 1A with a large contact area. In order to adsorb or absorb moisture, absorb water and efficiently adsorb, absorb, or absorb pollutants, it is desirable to have a large adsorption capacity, moisture absorption, or water absorption capacity. In order to firmly adsorb and fix or decompose, it has a catalytic action and a strong base substitution property. It can be assimilated with soil and can exhibit the function of adsorbing and fixing pollutants for a long time. Material is required. Artificial zeolite powder having an average particle size of 100 μm or less, a specific surface area of at least 100 m ² / g or more, and a base substitution capacity (meq / 100 g) of 200 mg or more is used as a material that meets such requirements.

Furthermore, the mixing ratio of the purification adjusting material 2A to the excavated soil amount varies depending on the contamination concentration and contamination distribution of the contaminated soil 1A and the base substitution capacity (meq / 100 g) of the artificial zeolite powder used for the purification adjusting material 2A. If the total amount of pollutants in the contaminated soil 1A is 20 mg / kg, then the base substitution capacity (meq / 100 g) of the artificial zeolite powder used in the present invention is 200 mg or more. Therefore, 100 g of artificial zeolite powder with an ion exchange capacity of 200 mg per 100 g of artificial zeolite powder corresponds to the ion exchange capacity of 10 kg of pollutant in the contaminated soil 1A. It has been clarified that an ion exchange capacity of about 3.0 to 3.5 times or more is suitable for the adsorption decomposition from the purification test.
Then, the dispersion mixing ratio of the purification adjusting material 2A to the excavated soil 1B obtained by excavating the contaminated soil 1A is 10 per 1000 kg of excavated soil when the total amount of pollutants in the contaminated soil 1A is 20 mg / kg. About 35kg or more is a standard.

Then, the purification adjustment material 2A in a required ratio with respect to the amount of excavated soil is sprinkled and the excavation soil 1B excavated into a coarse lump is crushed into fine particles and then mixed with the purification adjustment material 2A homogeneously for purification adjustment. There are no particular restrictions on the method of spraying the necessary amount of the purification adjusting material 2A and crushing and mixing the excavated soil 1B into a fine granule, although the work is continuous and efficient. In this case, as shown in FIG. 2, a storage tank 20A capable of storing a required amount of the purification adjustment material 2A at the front portion of the cart 20 capable of traveling on the surface of the excavated soil 1B, and the purification adjustment material 2A below the storage tank 20A. Dispersing and spraying spout 20B is provided and sprayed on the surface of excavated soil 1B at the required rate, and then the excavated soil 1B is crushed into fine particles and mixed with the sprayed purification regulator 2A. Plan Therefore, it is convenient to use a machine equipped with a rotary rotor 20C in which a large number of crushing and mixing blades 22C are formed on the outer peripheral surface of the rotary shaft 21C, and an optimum machine equipped with such a function is used as a civil engineering machine. Examples include stabilizers and drive harrows and rotary sowers used as agricultural machines.
In this case, when the excavated soil 1B reaches a depth of several meters or more, the deep tillage length of the crushing and mixing blade 22C and the like for crushing the coarse lump excavated soil 1B into fine particles and mixing with the purification adjusting material 2A is self-explanatory. Therefore, it is desirable to form the purification-adjusted soil 2B by stacking several layers in the required area range.

Thus, the pollutant deposited and accumulated in the contaminated soil 1A is eluted or washed over the entire surface of the purified soil 2B formed by spraying and mixing the soil 2B with the required weight ratio on the excavated soil 1B. In order to remove it and to recycle the soil that has been subjected to purification treatment, it is necessary to compact the soil, and the water spray leveling step 3 is performed in which the purified water 4 is sprinkled and infiltrated at the required weight ratio and the ground is leveled. .
In the sprinkling leveling step 3, as shown in FIG. 3, the purified water 4 to be sprinkled is eluted or washed away from the contaminated soil 1A of the purification-adjusted soil 2B, and the purification-adjusting material 2A 5 to 15% by weight of artificial zeolite powder with respect to water in order to promote adsorption fixation and adsorption decomposition to water, and to further increase adsorption fixation and adsorption decomposition of eluted or washed-out contaminants What was mixed and dispersed by the ratio is used.

Further, the water permeation amount of the purified water 4 is specifically determined by the contamination concentration and the contamination distribution or the contaminated soil porosity, etc. Generally, when the contamination concentration is high, the artificial zeolite powder When the purified water 4 mixed and dispersed at a weight ratio of about 10 to 15% is permeated into the soil gap at a penetration rate of about 30 to 50% and the contamination concentration is relatively low, the artificial zeolite powder From the results of numerous purification tests, the amount of sprinkling water that permeates the purified water 4 in which the body is mixed and dispersed at about 5 to 10% by weight into the soil gap with an infiltration filling rate of about 15 to 30%. Is preferred.
That is, in more detail explanation of the amount of water penetration, the artificial zeolite powder is 5.0% by weight when the total amount of pollutants has a relatively low contamination concentration of 20 mg / kg and the soil porosity is 50%. is calculated mixed dispersed in purified water ^{4 1m 3 × 0.5 × (0.15~0.3} ) = and 0.075 m ³ to 0.15 m ³ at a rate, 1 m ³ per approximately 7.5 to a 15l It becomes the amount of water spray penetration.

  Although there is no particular restriction in the construction method of the water spray leveling process 3, the water spray leveling process 3 is also of course continuous efficiency because the present invention aims to purify contaminated soil over a relatively large area. Therefore, as shown in FIG. 3, a water spray port is provided at a front portion of a carriage 40 that can travel on the surface of the purification-adjusted soil 2B from a storage tank 40A that stores purified water 4 via a water spray pump 40B. 40C is provided, and a leveling plate 40D or leveling roller 40E is provided at the rear portion of the carriage 40, so that the use of the machine is convenient. In this way, purification in the original position of the contaminated soil in the present invention is performed.

FIG. 4 is a construction explanatory diagram in which a permeation promoting hole 5 is drilled below the bottom of the excavated soil. Even in the soil survey prior to the purification of the contaminated soil, the contamination distribution of the contaminated soil is less than the soil concentration compared to the soil concentration. Accordingly, since the contamination concentration is rapidly reduced, the excavation depth in the practice of the present invention is usually made in a depth range that is equal to or greater than the environmental standard value for soil contamination.
However, the self-cleaning action does not work for soil contamination, and it accumulates and accumulates successively due to the scattering and falling pollutants and underground polluted water penetration. Therefore, even if the soil is below the environmental standard value, there is a risk that it will become contaminated soil over time, but further increasing the excavation depth will cause a significant increase in labor, time and cost.

Therefore, when excavating the excavated soil 1B, water is sprinkled on the surface of the purification-adjusted soil 2B by drilling the permeation promoting holes 5 of the purified water 4 with the required hole diameter and depth at equal intervals in the soil deeper than the bottom of the excavated soil. Purified water 4 is permeated into the purification-adjusted soil 2B, and further dispersed and collected in the permeation promoting holes 5 while permeating and diffusing deeply into the soil with a slight contamination concentration.
In such a case, the hole diameter, depth, and interval of the permeation promoting holes 5 are specifically determined by the contamination concentration, the contamination distribution, and the amount of sprinkled water of the purified water 4. It is desirable that the clarified adjusted soil 2B be embedded easily and be clogged. The depth is preferably about 1 to 2 cm, and the depth below the bottom of the excavated soil 1B is relatively permeable such as volcanic clay or sandy clay. In the case of a good soil quality, it may be formed to be approximately 0.3 to 1.0 m.

In addition, since pollutants tend to adhere and accumulate in large amounts and firmly on fine-grained soils such as clay and humus soil, such pollutants are also adsorbed and effectively adsorbed to the purification regulator 2A for adsorption fixation or adsorption decomposition. In order to achieve this, it is desirable that the contaminants deposited and accumulated on the clay or humus soil are separated and eluted or removed and washed.
In order to achieve this, it is advantageous to separate using a cohesive discrete force due to the coagulation action, so that calcium sulfate is mixed and dispersed in a proportion of 0.5 to 5.0% by weight as a coagulant that is strong against the purified water 4. In addition, it is preferable to permeate with water.
Furthermore, although there are a wide variety of pollutants, in the case of inorganic compounds such as heavy metals and arsenic, sufficient purification cannot be achieved only by the catalytic action of the purification regulator 2A and strong base substitution. Therefore, it is desirable to promote the adsorption and fixation after reducing the concentration of pollutants such as heavy metals and inorganic compounds. For this purpose, 0.5 to 5.0% of the purified water 4 is required. It is proposed to mix and disperse the reducing agent consisting of ferrous sulfate in a weight ratio.
In such a case, the reason why calcium sulfate or ferrous sulfate is mixed and dispersed in the range of 0.5 to 5.0% by weight with respect to the purified water 4 is 0.5% by weight or less in any case. In this case, the aggregation dispersibility and the reducibility are not sufficiently exhibited. On the other hand, even if it exceeds 5.0% by weight, there is no significant difference in adsorbability and adsorbability. As another means, the same purification effect can be expected even when the calcium sulfate or ferrous sulfate is mixed with the purification adjustment material 2A in the purification adjustment material mixing step.

Experimental example

An example of soil purification experiment according to the present invention will be described below. The experimental zone was conducted in an open space of 330 m ² adjacent to the Kawawa-machi pre-industrial industrial waste collection site in Tsuzuki-ku, Yokohama.
As a soil survey prior to the experiment, 5m underground drilling was conducted, soil samples of the surface layer and 2.5m underground and 5m underground were collected, and pollutants, contamination concentration and contamination distribution were measured by the Kyoritsu Institute of Physical and Chemical Research simple pack test method. The results are as shown in Table 1, and the soil porosity was about 55% on the surface layer and about 50% inside the soil.

The experimental method upon serving without excavation soil excavated by backhoe over the entire according experimental sections depth 3m, at a rate of該掘cutting soil 1 m ³ per 15% volumetric weight with stabilizer, an average particle diameter of 30μm Then, a purification adjustment material composed of artificial zeolite powder having a specific surface area of 110 m ² / g and a base substitution capacity (meq / 100 g) of 255 mg was sprayed, and pulverized into fine particles and mixed to obtain a purification adjustment soil.
The range of 1/3 of Thus to take cleaning adjust the soil surface, with the purified water that artificial zeolite powder were mixed and dispersed in a 10% weight ratio relative to water is sprinkled penetration at a rate of 1 m ² per 150l experiments 1 m of purified water in which artificial zeolite powder is mixed and dispersed at a rate of 10% by weight and ferrous sulfate at a rate of 3% by weight in the range of 1/3 of the surface of the soil to be purified and adjusted. Water is infiltrated at a rate of 150 liters per ² to make experimental zone B, and in the range of 1/3 of the surface of the clarified soil, the artificial zeolite powder is 10% by weight and calcium sulfate is 3% by weight. The purified water mixed and dispersed in (1) was infiltrated with water at a rate of 150 liters per 1 m ² to obtain experimental group C.

  Soil purification is determined using the simple pack test method of Kyoritsu Riken, and soil samples are taken for each elapsed time after the purification treatment from the surface of Experiment Zone A, Experiment Zone B, and Experiment Zone C, and at a depth of 3 m, respectively. The results obtained are shown in Table 2.

The invention's effect

As described above, according to the present invention, the depth of excavation can be determined because the contamination state, the contamination distribution, and the soil porosity are grasped by the soil survey prior to the purification of the contaminated soil, and the solidified area has a high contamination concentration and is solidified. Contaminated soil can be easily and efficiently excavated by civil engineering and agricultural machinery such as backhoes and deep-plow rotarys, and can be used as excavated soil. Because the mixing is performed while sprinkling the purification conditioner at the required important ratio with respect to the volume and crushing the coarse lump excavated soil into fine granules, the purification adjustment soil is mixed with the purification conditioner extremely efficiently and evenly The purification-adjusting material, which is formed by spraying and mixing, is made of artificial zeolite powder, has a particle size of 100 μm or less, a specific surface area of 100 m ² / g or more, and a base substitution capacity ( Since a meq / 100g) of 200 mg or more is used, the pollutant that comes into contact is actively and efficiently adsorbed, absorbed or absorbed by its very large contact surface area ratio and large adsorption, moisture absorption, or water absorption capacity. Adsorbed, moisture-absorbed and water-absorbed pollutants are adsorbed, fixed or adsorbed, decomposed and purified by their inherently retained catalytic action and strong base substitution, especially with a large amount of accumulated contaminants. Organic compounds and the like are not adsorbed and saturated with adsorption decomposition and exhibit a purification effect over a long period of time, so that even when permeation and diffusion of contaminated groundwater is performed, the purification effect is sufficiently exhibited.

And since the purified water in which artificial zeolite powder is mixed and dispersed at a ratio of 5 to 15% by weight with respect to water is infiltrated into the entire surface of the purification-adjusted soil at a required weight ratio, the pollutants in the contaminated soil Because it is eluted or washed away, adsorption, moisture absorption and water absorption to the purification regulator made of artificial zeolite powder are further promoted, and a high purification effect can be expected. In addition, since the flat leveling is performed, the contaminated soil over a wide area can be purified in a very simple and efficient manner at a low cost.
Furthermore, even when a large amount of contaminants such as clay and humus soil adhere and accumulate, heavy metals and inorganic materials that are easily separated and eluted and separated and washed away by the cohesive discrete force of calcium sulfate, or that are difficult to adsorb and fix and adsorb. This is a contaminated soil remediation method that has many features such as the reduction of pollutants such as compounds themselves with ferrous sulfate to enhance safety and also promotes adsorption fixation or adsorption decomposition, thereby significantly improving purification.

  It is construction explanatory drawing of an excavation process.   It is construction explanatory drawing of the purification adjustment material mixing process.   It is construction explanatory drawing of a watering leveling process.   It is sectional explanatory drawing by which the penetration promotion hole was drilled by the excavation soil bottom face.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excavation process 1A Contaminated soil 1B Excavated soil 2 Purification adjustment material mixing process 2A Purification adjustment material 2B Purification adjustment soil 20 Cart 20A for purification adjustment soil construction Purification adjustment material storage tank 20B Sprinkling port 20C Rotating rotor 21C Rotating shaft 22C Crushing and mixing blade 3 Water sprinkling leveling process 4 Purified water 40 Carriage 40A for water sprinkling leveling construction Storage tank 40B Water sprinkling pump 40C Water sprinkling port 40D Leveling plate 40E Leveling roller 5 Penetration promotion hole

Claims (4)

Boring the appropriate position of the contaminated soil, soil survey to determine the soil contamination status, contamination distribution and porosity, and excavating the contaminated soil solidified from the contaminated soil surface to the required depth based on the soil survey is rough Excavation process to make a lump of excavated soil, purification adjustment material mixing process to disperse purification adjustment material at a required weight ratio with respect to the amount of excavated soil and crushing and mixing into fine granules to make purification adjustment soil, and the average A purification regulator composed of artificial zeolite powder having a particle size of 100 μm or less, a specific surface area of at least 100 m ² / g or more and a base substitution capacity (meq / 100 g) of 200 mg or more, and spraying purified water throughout the purification regulation soil surface A contaminated soil remediation process comprising a sprinkling leveling process that dampens and levels and purified water in which artificial zeolite powder is mixed and dispersed at a ratio of 5 to 15% by weight with respect to water. Law.   2. The method for purifying contaminated soil according to claim 1, wherein permeation promoting holes for purified water are drilled in the soil deeper than the bottom surface of the excavated excavated soil with a required hole diameter and depth at equal intervals.   The method for purifying contaminated soil according to claim 1 or 2, wherein calcium sulfate is mixed and dispersed in the purified water at a weight ratio of 0.5 to 5.0%.   The method for purifying contaminated soil according to claim 1 or 2, wherein ferrous sulfate is mixed and dispersed in the purified water at a weight ratio of 0.5 to 5.0%.

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