JP4574241B2 - Pollution control methods - Google Patents

Description

The present invention is, for example, relates such heavy oil, gasoline or the like in petroleum oils (petroleum hydrocarbons) Pollution Control how soil containing contaminants comprising a.

  On the site of a factory or the site of a gas station, the soil may contain contaminants composed of petroleum oils such as heavy oil and gasoline. If such soil is left as it is, there is a risk that pollutants will diffuse into the surrounding environment through groundwater or the like. Therefore, it is necessary to take some countermeasures against soil contaminated with pollutants.

  There are several ways to deal with this type of pollution, but in order to remove the pollutants by the decomposition of microorganisms, an excavator with a stirring blade is inserted at the location of the pollutants on the ground. There is a method in which microorganisms are injected into soil, and the contaminants are decomposed and removed by a purification column formed in the soil by mixing the soil with microorganisms using an excavator (see, for example, Patent Document 1).

JP 2001-219157 A

  However, since the above prior art is a local treatment for forming a purification column in the intrusion range of the excavator at the position where the contaminant is present, the purification column is formed so as to completely cover the existing range of the underground contaminant. This is not always easy, and in some cases, there is a risk of leaving a source of pollution in the ground without taking any countermeasures. In addition, since a period of time is usually required for a contaminant to be decomposed by microorganisms, even if a high concentration of contaminant is locally treated, such as when there is a flow in groundwater, Over time, the contaminants may move out of the purification column and diffuse the contaminated area.

The present invention has been made in consideration of these circumstances, and its object is to purify without leaving underground pollutants, provides a pollution abatement how that can prevent the diffusion of contaminants is there.

In order to achieve the above-mentioned object, the first invention provides a procedure for preliminarily investigating the distribution of pollutants on the site to be treated , the soil quality, the geological gradient, and the groundwater level gradient, and the results of this preliminary survey. Based on the procedure for identifying the movement direction of the substance and the identified movement direction of the pollutant, the site along the boundary with the adjacent land adjacent to the site downstream of the movement direction of the contaminant. Polluted earth and sand material mixed with at least one of microorganisms that decompose pollutants or nutrients that activate microorganisms is backfilled in the excavated area and contamination enters the earth There is provided a pollution control method characterized by performing a procedure for forming a pollutant decomposition zone for selectively collecting, decomposing and removing substances.

According to a second invention, in the first invention, the pollutant is purified by excavating the high-concentration distribution region of the investigated pollutant and mixing the excavated sediment with lime or an improvement material containing a lime-based chemical. Provided is a soil contamination countermeasure method characterized in that after the treatment, the treated soil is backfilled in an excavation site.

A third invention is the first or second inventions in Oite, the sediment material constituting the pollutant destruction zone, characterized by mixing an adsorbent for adsorbing contaminants.

A fourth invention is characterized in that, in any one of the first to third inventions, the pollutant decomposition zone is formed so as to cover a height range of an existing area of the pollutant remaining in the ground. Provide soil pollution control methods.

A fifth invention provides a soil contamination countermeasure method according to any one of the first to fourth inventions, wherein a pipe for injecting air or a nutrient is inserted into or near the pollutant decomposition zone. provide.

A sixth invention is the soil according to any one of the first to fifth inventions, wherein a pipe for injecting a nutrient or a microorganism is inserted at a position upstream of the pollutant decomposition zone in the moving direction. Provide pollution control methods.

As for the seventh invention, in the first invention, as a result of investigating in advance the distribution of pollutants, soil quality, geological gradient, and groundwater level gradient, a part of the pollutants have invaded from their own site to the adjacent land, In the case where the geological gradient is a downward slope from the adjacent land toward the own site, the pollutant is purified by excavating the contaminated soil of the own site and mixing with lime or a chemical based on lime, After the pollutant has been excavated, the pollutant decomposition zone is formed on the adjacent land side of the site where the pollutant has been excavated, and then mixed with the drug in the remaining portion of the site where the pollutant has been excavated. Provided is a pollution control method characterized by backfilling treated soil.

  According to the present invention, the pollutant remaining in the ground can be decomposed and removed by the pollutant decomposition zone formed on the downstream side in the moving direction of the pollutant, so that the target pollutant is purified without leaving, for example, It is possible to reliably prevent the diffusion of pollutants to the adjacent land.

Hereinafter, embodiments of the pollution control method of the present invention and the pollutant decomposition zone used therefor will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a construction example of the first embodiment of the pollution control method of the present invention, and FIG. 2 is a horizontal sectional view taken along the line II-II in FIG.

  In FIG. 1, for example, a pollutant b (in this case, petroleum-based oil (petroleum hydrocarbon) such as gasoline or kerosene) leaks from a gas station (or an oil tank station, etc.), and the soil in the site c of the gas station a The case where it is diffused is shown as a model.

  At present, there are about 50,000 petrol stations throughout Japan, but many have opened in the old days, and many have been in operation for about 20 to 40 years. There is also such a background. In FIG. 1, when construction work of the building e in the adjacent land d, expansion / renovation of the gas station a itself, etc. are performed or an earthquake hits, the site c where the gas station a was built The ground is stressed. In such a state, for example, if a tank or pipe (not shown) buried due to aging cracks, a pressure is applied to the crack to generate a pinhole, and petroleum oil (pollutant b) is generated through the pinhole. Leakage may occur as shown.

  The pipes and tanks of the gas station a are often buried with sandy soil. When the contaminant b leaks, the contaminant b flows down through the sandy soil to the groundwater level f as shown in FIG. . And since the specific substance b which consists of petroleum oil has a specific gravity smaller than water, it diffuses along the flow of groundwater. In this process, the pollutant b permeates into the soil to cause soil contamination, or is mixed with groundwater to cause groundwater contamination.

  Pollutant b leaking from petrol station a usually includes benzene (regulated value: elution amount 0.01 mg / L), which is a designated hazardous substance in the Soil Contamination Countermeasures Law, and toluene, which is an important monitoring item in the Groundwater Pollution Control Law. (Reference value: 0.6 mg / L), xylene (reference value: 0.4 mg / L) and the like are included. Such pollutants b are distributed at a high concentration in the vicinity of the soil of the leakage path and the groundwater level f, but have a specific gravity smaller than that of water and easily volatilize. The range is also distributed at a low concentration as a gaseous body. And the pollutant b of the high concentration distribution area | region g moves with the flow of groundwater, transfers to the low concentration distribution area | region h, and is spread | diffused with progress of time.

  The movement speed of groundwater varies depending on the soil quality (permeability coefficient), water head difference (water level gradient), stratum gradient, etc. of the surrounding soil. For example, sandy soil may move several tens of meters per year. For this reason, if the groundwater moves toward the adjacent land d as shown in FIG. 1, the risk that the pollutant b may enter the adjacent land d if the pollution measures after the pollutant b leaks are delayed. There is sex. In this case, if the pollutant b is diffused to the adjacent land d, it is difficult for the owner of the site c to take measures against the contamination at the adjacent land d, and places a great burden on the owner of the adjacent land d. Before the pollutant b diffuses, it is necessary to take measures against pollution within the site c.

  Therefore, in the pollution control method of the present embodiment, the procedure for investigating the distribution of the pollutant b, the soil, the formation gradient, the groundwater level gradient, etc. in advance, and the movement direction of the pollutant b are examined from the result of the advance investigation. And a sediment material mixed with at least one of microorganisms that decompose pollutants b or nutrients that activate microorganisms based on the moving direction of the pollutants b studied and downstream of the existence range of the pollutants b. And a procedure for forming a pollutant decomposition zone i for selectively collecting, decomposing and removing the pollutant b entering (moving) there.

  The pollutant decomposition zone i may be arranged on the downstream side of the pollutant b. However, as shown in FIG. 1, the pollutant decomposition zone i is provided in the vicinity of the boundary j with the adjacent land d adjacent to the downstream side in the groundwater flow direction on the site c. It is preferable. The shape of the pollutant decomposition zone i is not strictly limited. However, when the pollutant b is awaited and decomposed on the downstream side in the moving direction of the pollutant b as in the present embodiment, for example, the pollutant It is preferable to provide a band along the boundary j with the adjacent land d so as to be substantially orthogonal to the moving direction of b, and it may be formed in a U-shape when viewed in a horizontal section as shown in FIG.

  However, the diffusion range of the pollutant b that can be expanded before reaching the pollutant decomposition zone i takes into account the result of the preliminary investigation and the distance from the pollutant source to the pollutant decomposition zone i, Therefore, it is necessary to sufficiently examine the length and depth of the pollutant decomposition zone i so as not to generate the pollutant b that enters the adjacent land d without being guided to the ground. As a specific example of the depth, for example, the height range of the existing region of the contaminant b remaining in the ground (in this embodiment, the height range above and below the groundwater level f, for example, about 1 m above and below the groundwater level f). It is preferable to form the pollutant decomposition product i so as to cover the surface.

  If the moving direction of the pollutant b cannot be specified, the pollutant decomposition zone i may be formed in a circumferential shape so as to surround the periphery of the pollution source. In short, the pollutant decomposition zone i may be formed so that all the pollutants b are guided to the pollutant decomposition zone i at a position downstream of the moving direction of the pollutant b moving with time.

  The pollutant decomposition zone i is made of earth and sand material mixed with at least one of microorganisms (bacteria) that decompose the pollutant b or nutrients that activate the microorganisms, in other words, earth and sand with an increased content of microorganisms having oil-degrading ability. Or soil activated by microorganisms present there. Therefore, even if the pollutant decomposition zone i is arranged in a positional relationship that interferes with the groundwater, the groundwater is not actually blocked and passes through the pollutant decomposition zone i. That is, only the pollutant b transferred by the ground water is selectively collected and decomposed and removed by the microorganisms when passing through the pollutant decomposition zone i. In addition, the earth and sand material which backfills underground and comprises the pollutant decomposition zone i is mixed with microbial material, a nutrient, etc. as needed, and after a predetermined period (for example, about 1 day), it is refilled.

  In addition, although it depends on the contamination level, as a result of the investigation, it was confirmed that a part of the contaminant b would not pass through the contaminant decomposition zone i without being completely decomposed and removed in the contaminant decomposition zone i. When the contamination level of the substance (contamination source) is too high, it is preferable to excavate the high concentration distribution region g separately. The excavated soil in the high-concentration distribution region g is mixed with, for example, lime or an improving material containing a chemical mainly composed of lime, volatilizes and removes the pollutant b by hydration reaction heat, and then backfilled at the excavation site. Further, the excavated soil in the high concentration distribution region g may be taken out of the field and treated at the final disposal site, and the clean soil may be newly refilled in the excavation site.

  In addition, the microorganisms that inhabit the pollutant decomposition zone i may be those that have oil-degrading ability that originally inhabited the soil or other newly mixed microbial materials as described above, but preferably aerobic microorganisms. Used. In addition, it is preferable to inhabit a plurality of types of microorganisms having different functions in the pollutant decomposition zone i, rather than inhabiting one type of microorganisms, because a synergistic effect is expected.

  By inhabiting multiple types of microorganisms in this way, pollutants that are mixed with heavy tar-like hydrocarbons such as petroleum, coal tar, and organic sludge, and refined hydrocarbon substances such as gasoline and light oil are mixed. Accelerating metabolic capacity is demonstrated when targeting. Examples of the function of the microorganism include decomposition of phenolic hydrocarbons, decomposition of proteins / starch / cellulose, decomposition of high fat / grease, production of oil-degrading enzymes, and the like.

As an example of a microbial material currently on the market, “Bacteria GT1000-HC (trade name) / manufactured by Biogenesis” and the like can be mentioned. It is preferable that the blending ratio of “GT1000-HC” in the pollutant decomposition zone i is higher as the concentration of the pollutant b in the soil of the site c is higher if it is within an allowable range. If the mixing ratio of the microorganisms in the pollutant decomposition zone i is too low, the purification of the soil does not proceed sufficiently, and if more than necessary, the purification proceeds sufficiently, but it is uneconomical. Although depending on the content of the pollutant b in the soil, it is usually preferable to consider so that about 50 to 200 g of microorganisms can inhabit 1 m ^{3 of} the soil.

  In addition, when a nutrient is added to the soil in the pollutant decomposition zone i in order to enhance the decomposition action of the contaminant b by microorganisms, a commercially available one may be used as the nutrient to be added. -It is desirable to use a mixture of potassium. As the nitrogen source, for example, ammonium chloride, ammonium sulfate, ammonium nitrate and the like are preferably used. As the phosphoric acid source, for example, phosphate, superphosphate, metaphosphate, polyphosphate, and the like are preferably used. Moreover, as a potassium source, what mix | blended potassium chloride, potassium carbonate etc., for example is used preferably.

In addition, when adding a nutrient to the pollutant decomposition zone of the present invention, an example of the ratio of nitrogen, phosphate, and potassium of the nutrient is approximately 10:10:10 to 25:15:15, It is preferable to mix a relatively large nitrogen component ratio. Further, it is preferable that the amount of the nutrient added in the pollutant decomposition zone i is within an allowable range. Specifically, although it depends on the soil contamination level of the site c, a preferable value is about 50 to 200 g / m ³ .

Further, when it is desired to enhance the trapping ability of the pollutant b compared to the case where only the above-mentioned microorganisms and nutrients are mixed depending on the pollution level, the adsorbent that selectively adsorbs the target pollutant is set in the pollutant decomposition zone i. It is still more effective when mixed with the earth and sand material. As this adsorbent, any adsorbent capable of adsorbing petroleum oil can be used. For example, “Oil Sponge (trade name) / manufactured by Biogenesis Technology Co., Ltd.” can be used. In the case of this “oil sponge”, for example, it is preferable to mix about ^{3 to} 13.5 kg per 1 m ^{3 of} earth and sand. In addition, since there are some adsorbents that contain microorganisms having oil-degrading ability and nutrients thereof, it is more preferable to use this type of adsorbent. In addition, for example, humus soil, compost, etc. can be used as the adsorbent and are easily available. In addition to the above microbial materials, nutrients, and adsorbents, it is also possible to mix a release agent into the pollutant decomposition zone i as necessary.

  According to the pollution control method of the present embodiment as described above, the soil in the high-concentration pollution distribution region is separately purified by some method, for example, mixed with an improving material, if necessary. The low-concentration pollutant can be subsequently decomposed and removed by the pollutant decomposition zone formed on the downstream side in the moving direction. Thereby, it can purify | clean without leaving the target pollutant, and can prevent the spreading | diffusion of the pollutant to an adjacent land etc. reliably.

  Depending on the contamination level, adsorbent can be mixed in the pollutant decomposition zone and the adsorbent can adsorb and retain the contaminant, so that the retained contaminant can be decomposed into microorganisms over a sufficient amount of time. It is possible to more reliably prevent some pollutants from passing through the pollutant decomposition zone and further prevent the pollutants from spreading.

Heretofore, as a countermeasure against such contamination, generally, processing has been performed in which excavated contaminated soil is carried to a waste disposal site, a cement plant, etc., and uncontaminated material (for example, mountain sand) is backfilled in an excavation site. It was. However, it is expensive to carry out and dispose of the contaminated soil outside the contaminated site (for example, 40,000 to 100,000 yen / m ³ ). It was limited to. As a result, low-concentration sources remain at the contaminated site, and in some situations, contamination may remain in groundwater. Conventionally, such a case has been generally dealt with by boring the contaminated site to pump up the contaminated groundwater and treating it with water.
However, this method requires that groundwater pumping equipment with residual pollutants be installed for a long period of time, which is expensive, and the land is planned to be reused or sold for immediate use. Etc. could not be adopted.

  On the other hand, in this embodiment, even if it is necessary to take measures against contamination in advance for a high-concentration contamination distribution region with a high contamination level, the above-described improved material is of course used when excavated and taken to the final disposal site. Even if it is mixed with transpiration to remove the pollutants, the construction period is short, and it is possible to immediately shift to land reuse. In this embodiment, even if the level of contamination that can be handled in the pollutant decomposition zone remains in the soil, there is no need to perform any construction continuously and if it is left as it is after construction, The remaining pollutant moves and is decomposed and removed when it reaches the pollutant decomposition zone. Since the pollutant decomposition zone itself is also earth and sand, it can be handled as part of the site immediately after construction. In other words, there is no need to remove the pollutant decomposition zone after the remaining pollutants have been decomposed and removed, so once the pollutant decomposition zone is formed, a building can be quickly built on the pollutant decomposition zone. There is no problem. Therefore, it is possible to quickly finish the construction of pollution measures and to reuse or sell the land immediately.

  In addition, this contaminated soil countermeasure method simply enhances the oil resolution by adding nutrients to activate microorganisms that originally lived, adding microorganisms themselves, or adding microorganisms and nutrients. The construction cost is extremely low because it forms a pollutant decomposition zone composed of soil and sand.

  Moreover, instead of the pollutant decomposition zone in this embodiment, a sheet pile or an impermeable substance is embedded in a fence shape in the soil downstream in the movement direction of the pollutant, thereby blocking the pollutant trying to flow out to the adjacent land. One measure is to decompose the damped pollutants with microorganisms.

  However, in this case, the flow of groundwater is also dammed, and there is a risk that contaminants may flow out of the fence as the dammed groundwater overflows over the fence. Even if the fence is formed in a circumferential shape and is disposed so as to surround the periphery of the pollution source, the contaminant may leak from the lower side of the fence together with the groundwater.

  On the other hand, in this embodiment, since the pollutant decomposition zone is formed of earth and sand, only the contaminants that have entered the pollutant decomposition zone are collected and decomposed and removed without hindering the flow of groundwater. It is possible to take measures against pollution without getting over the material decomposition zone and leaking the pollutants.

  In addition to the above, in the present embodiment, a pollutant decomposition zone is simply formed by mixing at least one of microorganisms or nutrients thereof in the soil downstream in the movement direction of the pollutants. Construction is possible with a heavy excavator such as a hydraulic excavator. Even when it is necessary to excavate a high-concentration contamination distribution area depending on the contamination level, it is only necessary to excavate heavy machinery, and the excavated heavy soil can be mixed and backfilled with the improved material. When mixing microorganisms, nutrients, adsorbents, improvers, etc. with earth and sand, it is desirable to use a mixing device when a more uniform mixing process is required. It is enough if you prepare it.

As described above, it is a great merit of the present embodiment that the construction can be performed with a general facility such as a heavy excavator and a mixing device without requiring a special device or a large-scale device.
In addition, the equipment used for constructing the contamination countermeasure method of this embodiment will be described later with reference to the drawings.

  FIG. 3 is a longitudinal sectional view showing a construction example of the second embodiment of the pollution control method of the present invention, and FIG. 4 is a horizontal sectional view taken along the line IV-IV in FIG. In these drawings, parts similar to those in FIGS. 1 and 2 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 3 and 4, the present embodiment is different from the first embodiment of the present invention described above in that the pipe k for injecting air or nutrient (or both) is connected to the pollutant decomposition zone i. Or it is the point inserted in the vicinity, About other construction methods, it is the same as that of 1st Embodiment of this invention.

  A plurality of holes are provided in the side surface of the pipe k, and the pollutant decomposition zone i or the earth and sand in the vicinity thereof comes into contact with the space in the pipe k through these holes. When supplying air to microorganisms living in the pollutant decomposition zone i, for example, an air supply source (not shown) such as a compressor is connected to the pipe k, and a plurality of holes provided on the side surface of the pipe k are connected. The air is blown out. The length and shape of the pipe k are not particularly limited. For example, it is sufficient to use a general straight steel pipe having the same length as the depth of the contaminant decomposition zone i. Of course, a curved pipe may be used.

  However, even if the air supply source is not connected and air is not actively blown out from the pipe k in this way, the pipe k is simply inserted in the vertical direction, and the pollutant decomposition zone i or the soil in the vicinity thereof is in the pipe k. The effect of oxygen supply to microorganisms can be expected just by contacting with air.

  Further, the pipe k may be used not only for supplying air to microorganisms but also for supplying nutrients to microorganisms living in the pollutant decomposition zone i. In this case, the nutrient solution may simply be poured into the pipe k so that the nutrient solution oozes out from the hole on the side surface of the pipe k into the pollutant decomposition zone i, or a tank (not shown) storing the nutrient solution. May be connected to the pipe k so that the nutrient in the tank is appropriately leached into the soil of the pollutant decomposition zone i through the pipe k.

  In addition to air and nutrients, for example, microbial material may be injected from the pipe k into the pollutant decomposition zone i, and the pollutant decomposition zone i may be supplemented with microorganisms. In this case, a fluid carrying microorganisms may be supplied to the pipe k, or a solid microorganism carrier may be injected in some cases.

  According to this embodiment, the same effects as those of the first embodiment of the present invention shown in FIGS. 1 and 2 can be obtained, and air and nutrients can be introduced into the soil of the pollutant decomposition zone i through the pipe k. By supplying the agent, the microorganisms living in the pollutant decomposition zone i are further activated, and the degradation of the pollutant b can be promoted. Even when the microbial material is supplemented by the pipe k, the decomposition action of the pollutant b can be improved by increasing the number of microorganisms in the pollutant decomposition zone i.

  FIG. 5 is a longitudinal sectional view showing a construction example of the third embodiment of the pollution control method of the present invention, and FIG. 6 is a horizontal sectional view taken along the VI-VI section in FIG. In these figures, the same parts as those in the previous figures are denoted by the same reference numerals and description thereof is omitted.

  The difference between the present embodiment and the second embodiment of the present invention described above with reference to FIGS. 3 and 4 is that the nutrient solution or the nutrient solution is located at the upstream side of the pollutant decomposition zone i in the moving direction of the pollutant b. The pipe l for injecting the microbial material (or both) is provided, and other construction methods are the same as in the second embodiment of the present invention.

  The pipe l is the same as the pipe k inserted in the pollutant decomposition zone i, but the length, arrangement, and number of installations are taken into account in advance investigation results such as the concentration and direction of movement of the pollutant b and soil quality. decide. 5 and 6 show an example in which a plurality of pipes l are arranged so as to cover the inlet portion of the pollutant decomposition zone i formed in a U-shape when viewed from above.

  In this embodiment, if the nutrient is injected from the pipe l, the nutrient spreads to the microorganisms that live in the soil on the downstream side from the vicinity of the pipe l, and the microorganisms that live in the range can be activated. Before reaching the decomposition zone i, the pollutant b can be actively decomposed to reduce its concentration in advance. In addition, by injecting microbial material from the pipe l, the number of microorganisms near the pipe l can be increased, so that the pollutant b is actively decomposed before reaching the pollutant decomposition zone i in the same manner. The concentration can be reduced in advance. Of course, in addition to the pretreatment effect until reaching the pollutant decomposition zone i, according to the present embodiment, the same as the second embodiment of the present invention described above with reference to FIGS. The effect of can also be obtained.

  In addition, it is not limited to a nutrient or a microbial material, For example, even if it supplies air from the pipe l, it will lead to activation of microorganisms and can anticipate the effect similar to the above. Further, the effect can be obtained by using only the pipe l alone without using the pipe k together.

  FIG. 7 is a longitudinal sectional view of an example of a site to be constructed in the fourth embodiment of the pollution control method of the present invention. In FIG. 7, the same parts as those in the previous drawings are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 7 shows an example in which a pollutant b (heavy oil-based oil) leaks from a buried pipe p in a site c where the formation is formed in the order of the surface layer, the loam layer m, the clay layer n, and the sandy layer o. ing. Each layer m, n, o has a geological gradient that slopes downward from the adjacent site d to the site c at least near the boundary between the site c and its adjacent site d, and the groundwater level is located below the sandy layer o. Suppose you are.

  In such a site c, the leaked pollutant b flows down from the pipe p almost directly under the loam layer m, and when it reaches the clay layer n, it is horizontal along the boundary between the loam layer m and the clay layer n. Has spread. The pollutant b exists as a liquid near the leakage path and the boundary between the loam layer m and the clay layer n and forms a high concentration distribution region g. Further, around the high concentration distribution region g, a pollutant b diffused in the loam layer m as a gaseous body forms a low concentration distribution region h in a wide range, and a part of the contaminant b penetrates to the adjacent land d. is doing.

  FIG. 8 is a longitudinal sectional view showing an example of construction of the fourth embodiment of the pollution control method of the present invention for the site c shown in FIG. In FIG. 8, the same parts as those in the previous drawings are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 8, the entire loam layer m infiltrated with the pollutant b in the site c and the upper layer portion of the clay layer n are excavated and mixed with lime or a lime-based improvement material to evaporate the pollutant b. Then, the treated soil is backfilled to form a treated soil layer q, thereby removing the pollutant b in its own site c.

  At this time, as described above, since the low concentration distribution area h of the pollutant b is diffused to the adjacent ground d, if the contaminated area is simply replaced with the treated soil layer q, then the site c is changed from the adjacent land d to the site c by the geological gradient. There is a possibility that the pollutant b in the low concentration distribution region h is returned. That is, when the pollutant b in the site c is removed, there is a possibility that the moving direction of the pollutant b is directed from the adjacent site d to the site c due to the geological gradient.

  In such a case, there is a possibility that the pollutant b diffused in the adjacent land d can be decomposed and removed in its own site c, and therefore, preferably on the downstream side in the moving direction of the pollutant b in the site c. Forms a pollutant decomposition zone i in a band shape along the boundary j with the adjacent land d in the site c. At that time, in the topography illustrated in FIGS. 7 and 8, the contaminant b is highly likely to move near the boundary between the loam layer m and the clay layer n, in other words, on the clay layer n. Therefore, it is preferable to form the pollutant decomposition zone i so as to increase the thickness in the moving direction of the pollutant b as it approaches the clay layer n as shown in FIG. Therefore, in actual construction, the pollutant decomposition zone i as shown in FIG. 8 is formed before the treated soil is refilled in the excavation site, and after the pollutant decomposition zone i is formed, the remaining space portion is formed. The treated soil layer q is formed.

  As described above, in this embodiment, the pollutant decomposition zone i is formed on the downstream side in the moving direction of the pollutant b, so that the pollutant b can be collected and reliably decomposed and prevented from being diffused. Although there is no change, especially in the case of this embodiment, it is possible to decompose and remove the pollutant diffused in the adjacent land d and to prevent re-contamination of the site c.

  Also, not only when there is contamination on your own site, but if there is a suspicion of contamination in the adjacent land, if a pollutant decomposition zone is formed near the boundary with the adjacent land, intrusion of pollutants from the adjacent land will occur in advance. Can be prevented. For example, if there is a history of use and leakage of VOC (volatile organic compounds) such as tetrachlorethylene and trichlorethylene in a neighboring plant, no matter how much the site is cleaned, contaminants may enter the site from the adjacent site. There is. In such a case, forming a pollutant decomposition zone at the boundary with the adjacent land in advance is extremely effective from the viewpoint of preventing pollution. Needless to say, when the site is not contaminated as described above, the process of forming the treated soil layer is not necessary as described with reference to FIG. 8, and it is sufficient to form the pollutant decomposition zone.

  Also in this embodiment, if an adsorbent is mixed in the pollutant decomposition zone, or if pipes k, l, etc. are used as described in the second and third embodiments of the present invention, it will be more effective. Is.

  FIG. 9 is a longitudinal sectional view of an example of a site to be constructed in the fifth embodiment of the pollution control method of the present invention. In FIG. 9, the same parts as those in the previous drawings are denoted by the same reference numerals, and description thereof is omitted.

  As described above, when the pollutant b leaks from the gas station (or an oil tank station or the like) a, the pollutant b concentrates around the groundwater level f. In the example shown in FIG. 9, the model is a case where not much time has passed since the leakage, and the leakage range of the pollutant b is relatively narrow.

  In such a case, in the present embodiment, in the present embodiment, the procedure for investigating the distribution of the pollutant b in the site c to be treated in advance and the high concentration of the pollutant b based on the investigated pollutant b distribution. Excavate the distribution area g, mix at least one of microorganisms that decompose the pollutant b or nutrients that activate the microorganisms, backfill the area where the high concentration distribution area g existed, and invade (move) Contaminating soil treated with a procedure to form a pollutant decomposition zone i that selectively collects, decomposes and removes incoming contaminants b, and excavated soil mixed with lime or lime-based chemicals And backfilling the upper part of the material decomposition zone i.

Hereinafter, the construction procedure of the pollution control method of this embodiment will be described with reference to FIGS. 10 to 12.
When the distribution of the pollutant b in the site c is preliminarily investigated and the contamination distribution as shown in FIG. 9 is confirmed, first, the site c is excavated around the high concentration distribution region g as shown in FIG. At this time, if excavation is performed so as to cover the entire low concentration distribution region h, the amount of excavation becomes large, and therefore excavation is performed to such an extent that the entire high concentration distribution region g is covered. Of the excavated soil, clean soil that does not contain the pollutant b (soil near the surface, topsoil) is temporarily placed in a predetermined location, and contaminated soil that contains the pollutant b (high concentration distribution region). g and soil in the low concentration distribution region h) are mixed with lime or an improved material mainly composed of lime, and purified by transpiration of the pollutant b by hydration reaction heat. This treated soil is temporarily placed separately from the clean soil, and is cured for a predetermined period as necessary.

  In addition, exudate water from the surrounding soil to the excavation area r is pumped up by pumping means (not shown), for example, if necessary, and then the analysis result of the content of pollutant b is environmental regulations. Release after confirming that the value is satisfied.

  Next, an earth and sand material that constitutes a pollutant decomposition zone by adding and mixing adsorbent as needed together with at least one of microorganisms having oil-degrading ability or nutrients thereof to a part of the clean soil that has been temporarily placed As shown in FIG. 11, the soil material is backfilled at the location where the high concentration distribution region g existed before excavation, in other words, in the vicinity of the remaining low concentration distribution region h. The material decomposition zone i is formed.

  When the pollutant decomposition zone i is formed as shown in FIG. 11, as shown in FIG. 12, the treated soil that has been temporarily placed is backfilled on top of the pollutant decomposition zone i to form a treated soil layer q, Subsequently, the remaining clean soil is backfilled on top of the treated soil layer q to form a cover soil layer s, and the excavation region r is buried in layers with each layer i, q, s to complete the construction.

  In this embodiment, since the excavation is performed around the high concentration distribution region g of the pollutant b, the contaminated water from the low concentration distribution region h that has not been excavated and remains around the excavation region r after excavation is excavated. It enters the region r. Therefore, by forming the pollutant decomposition zone i in the excavation region r so as to be located at the place where the remaining pollutant b enters, the remaining pollutant b remaining in the ground can be decomposed and removed. , Can prevent the diffusion of contamination.

  That is, in each of the above-described embodiments, the moving direction of the pollutant b formed by the soil quality, the geological gradient, the water level gradient, etc. is analyzed, and the pollutant decomposition zone i is arranged downstream of the moving direction of the pollutant b. In this example, by excavating the high concentration distribution region g that forms the center of the contamination range, the pollutant b flows positively so that the contaminant b that remains without being excavated around it enters the excavation region r. It is made to form automatically. This is an example in which each of the above-described embodiments waits for the pollutant b that naturally moves to be decomposed and removed by the pollutant decomposition zone i, but in this example, the flow of the pollutant b is intended. It can be said that this is an example of forming and calling into the pollutant decomposition zone i.

  Of course, in this embodiment, it is more effective to use the pipes k, l, etc. as described in the second and FIG. 3 embodiments of the present invention.

  Further, in this embodiment, when the contamination level of the high-concentration contaminated area g is high, as described above, the contaminated soil is mixed with lime or an improving material containing a lime-based chemical as a main component, and the contaminant b is roughly mixed. After removing the transpiration, a microbial material or the like carrying microorganisms having oil resolution may be mixed with the treated soil, cured for a while, and then backfilled in the treated soil layer q. By doing in this way, contaminant b can be removed more reliably. In this case, the contaminant b entering the excavation region r can be decomposed and removed also in the treated soil layer q. Furthermore, since the pH of the treated soil is increased by mixing the lime-based improving material, it is actually harmless to the environment, but it may cause bad feelings to the land owners. However, by providing the treated soil with the function of decomposing the pollutants in this way, the mental surface is improved and it becomes easy to backfill.

  FIG. 13 (a) is a longitudinal sectional view of an example of a site to be constructed in the sixth embodiment of the pollution control method of the present invention, and FIG. 13 (b) is a construction of the sixth embodiment of the pollution control method of the present invention. It is a longitudinal cross-sectional view of an example. In FIGS. 13 (a) and 13 (b), portions similar to those in the previous drawings are given the same reference numerals and description thereof is omitted.

  In the fifth embodiment of the present invention described above with reference to FIGS. 9 to 12, the entire excavation region r that forms the pollutant decomposition zone i, the treated soil layer q, and the cover soil layer s is excavated on the ground. Although temporarily placed, in this embodiment, without temporarily placing a part of the soil that forms the pollutant decomposition zone i, it is mixed with microorganisms, nutrients, etc. in situ to form the pollutant degradation zone i An example of construction is described.

  That is, in FIG. 13 (a), first, the surface soil t without contamination in the excavation region r, the low-concentration soil u partially including the low-concentration distribution region h below it, and the high-concentration distribution below it. The high-concentration contaminated soil v composed of the entire region g and the low-concentration distribution region h is excavated and temporarily placed separately.

  Next, the excavated low-concentration soil u is put into the excavation area r together with microorganisms and nutrients, and mixed with the low-concentration contaminated soil w at the bottom of the excavation area r by, for example, a ground excavator or the like. As shown in FIG. 13B, the pollutant decomposition zone i is formed in situ. Subsequent construction is the same as that in the fifth embodiment, and the high-concentration contaminated soil v temporarily placed before or after (or in parallel with) the step of forming the pollutant decomposition zone i is mixed with the improving material to generate the pollutant b. Then, the treated soil is introduced into the upper part of the pollutant decomposition zone i to form a treated soil layer q. Finally, the top soil layer t is covered with the top of the treated soil layer q to form a soil covering layer s to complete the construction.

  According to the present embodiment, the same effect as that of the fifth embodiment can be obtained, but the temporary placing step of the soil constituting the pollutant decomposition zone i can be omitted, so the construction time is shortened. In addition, the processing space can be reduced. This embodiment is effective when the high concentration distribution region g exists at a high position, for example, when the groundwater level f is relatively high.

  In this embodiment, the pollutant decomposition zone i is formed with the low-concentration contaminated soils u and w. Of course, the pollutant decomposition zone i may be formed with clean soil. Depending on the presence of the contaminant b, the excavated soil may be treated differently. Needless to say, also in this embodiment, an adsorbent is mixed into the pollutant decomposition zone i, or pipes k, l, etc. are used as described in the second and FIG. 3 embodiments of the present invention. Is more effective.

  Next, several examples of apparatuses and systems suitable for implementing each embodiment of the soil contamination countermeasure method of the present invention described above will be described with reference to the drawings.

  FIG. 14 is a perspective view showing the overall structure of a heavy excavator as an example of an apparatus suitable for implementing each embodiment of the soil contamination countermeasure method of the present invention.

  FIG. 14 shows a hydraulic excavator as a typical example of heavy excavator. A hydraulic excavator 100 shown in FIG. 14 includes a traveling device 102 provided with an endless track crawler belt 101, a revolving body 103 that is turnable on the upper portion of the traveling device 102, and a revolving body 103 that is rotatably connected to the revolving body 103. And an articulated working device. The working device includes a boom 104 whose base end is pivotally supported by the swing body 103, an arm 105 rotatably connected to the boom 104, and a bucket 106 rotatably connected to the arm 105. Has been.

  With such a configuration, the excavator 100 runs on its own as needed, while scooping earth and sand into the bucket 106 and accumulating it at a predetermined location or supplying it to other devices. Further, it is also used when the work apparatus is appropriately operated to stir earth and sand with the bucket 106.

  An example of work in each embodiment of the soil contamination countermeasure of the present invention described above will be described. For example, in the first to third embodiments described above, the excavator 100 has a belt-like groove X at a place where a pollutant decomposition zone is formed. It is possible to perform an operation of excavating and forming a pollutant decomposition zone by backfilling the groove X with soil material of the pollutant decomposition zone in which microorganisms or nutrients are mixed with the excavated sediment. Of course, in other embodiments, it is also used for forming a pollutant decomposition zone. Needless to say, in each embodiment, the work of excavating a high concentration distribution area of the pollutant, the work of mixing the excavated contaminated soil with the improving material to generate the treated soil, the work of refilling the treated soil into the excavation site, the covering soil It can also be used for work to be performed.

  That is, although depending on the scale of the contamination site, as described above, the above-described embodiments of the soil contamination countermeasure method of the present invention can be implemented with a hydraulic excavator 100 as a minimum. When each embodiment is constructed with only 100, the number of devices required for soil contamination countermeasures can be extremely small and compact. In addition, since the traveling device 102 is provided, it is possible to travel freely in the field, and it is a great merit that loading and unloading with respect to a trailer or the like can be performed by itself without using a crane or the like. In addition, since it does not take up space and can move freely, it is extremely excellent in layout, and is particularly convenient in a narrow work site.

  FIG. 15 is a block diagram showing an extracted main part of an example of a system suitable for implementing each embodiment of the soil contamination countermeasure method of the present invention, and FIG. 16 is a side view showing the entire structure.

This system mixes excavated soil with microorganisms, nutrients, and adsorbents as appropriate, to generate sediment material in the pollutant decomposition zone, and mixes improved materials with excavated contaminated soil to volatilize and remove contaminants. It is applied to purification work.
In the following description, additives that are added to the earth and sand according to operations such as microorganisms (microorganism materials), nutrients, adsorbents, and improving materials may be collectively referred to as additives as appropriate.

  The system shown in FIGS. 15 and 16 includes the hydraulic excavator 100 used as earth and sand supply means for introducing excavated earth and sand, and a soil conditioner 200 for mixing the earth and sand introduced by the hydraulic excavator 100 with an additive. Has been.

  The hydraulic excavator 100 is the same as that shown in FIG. In this example, the hydraulic excavator 100 is used as means for supplying earth and sand to the soil improvement machine 200. However, for example, a belt conveyor or a screw conveyor may be used instead. In this case, it is more preferable to provide a storage means such as a hopper, to store a predetermined amount of earth and sand, and to transport the earth and sand continuously.

As shown in FIG. 16, the soil conditioner 200 includes a traveling device 45, a main body frame 10 on the traveling device 45, a sieving device 3, a hopper 4, a conveyor 5, a nutrient supply device 6 (see FIG. 15), mixing The traveling device 45 including the device 7, the additive supply device 39, the discharge conveyor 8, and the power device 9 includes a track frame 46 that is continuously provided at the lower part of the main body frame 10, and slaves that are provided at both ends of the track frame 46. A driving wheel (idler) 47 and a driving wheel 48, an endless track crawler belt 49 wound around the driven wheel 47 and the driving wheel 48, and a driving device 50 directly connected to the driving wheel 48 are configured.

FIG. 17 is a side view showing a detailed structure in the vicinity of the sieve device 3 and the hopper 4.
The sieving device 3 serves as a pulverizing and classifying means for receiving processing target soil excavated by, for example, a hydraulic excavator and the like and classifying (selecting) it according to the particle size while pulverizing it. Reference numeral 11 denotes a frame constituting the main body of the sieving device 3, and this frame 11 is elastically supported via a spring 14 by a support member 13 provided on the main body frame 10 via a support post 12. ing. Reference numeral 15 denotes a lattice member mounted in the frame 11, and 16 denotes a rotary drum inserted through a vibration shaft (not shown) of the lattice member 15. The rotary drum 16 is driven to rotate by a driving device (not shown). To do. Reference numeral 17 denotes a so-called tilt provided in the upper part of the sieve device 3.

  The hopper 4 is a frame-like member provided as receiving means for receiving earth and sand, and its upper end is fixed to the support member 13 so that its lower end is inclined according to the inclination angle of the conveyor 5. Moreover, in order to receive the earth and sand which passed the sieving apparatus 3 reliably, and to guide on the conveyance belt 24 (after-mentioned, refer FIG. 18) of the conveyance conveyor 5, it is an upward expansion shape. The size of the upper opening of the hopper 4 is larger than the frame 11 of the sieving device 3 in both the longitudinal direction and the width direction, and the width of the lower end is smaller than the width of the conveyor belt 24.

  Reference numeral 18 denotes an arch breaker provided in the hopper 4. The arch breaker 18 includes a rotating shaft 19 that is rotatably supported at both ends with respect to the hopper 4, a plurality of stirring rods 20 attached to the rotating shaft 19, and And a drive device 21 directly connected to the end of the rotary shaft 19 (the right end in FIG. 17).

  The transport conveyor 5 serves as a transport means for transporting the earth and sand received by the hopper 4 to the mixing device 7. As shown in FIGS. 15 and 16, the front side of the main body frame 10 (the left side in FIG. 16). ) Mounted at the end. The conveyor 5 extends slightly upward (preferably substantially horizontal) from the lower side of the hopper 4 toward the downstream side (right side in FIG. 16).

  FIG. 18 is a diagram showing a detailed structure in the vicinity of the downstream side of the conveyor 5. In FIG. 18, 22 is a conveyor frame of the conveyor 5, and 23 is a drive wheel supported at the downstream end (right side in FIG. 18) of the conveyor frame 22. A conveyor belt 24 is wound around a driven wheel (not shown) supported at the upstream end (left end in FIG. 18). With this configuration, the conveyor 5 rotates the driving wheels 23 with a driving device (not shown) to drive the conveyor belt 24 in a circulating manner. At this time, as shown in FIG. 18, an opening 4 a having a predetermined opening area is provided on the downstream side wall surface of the hopper 4, and the earth and sand conveyed by the conveying conveyor 5 are outside the hopper 4 through the opening 4 a. A certain amount is cut out. Although not particularly shown, it is preferable to project a so-called lug on the conveying surface of the conveying belt 24 in order to prevent earth and sand from slipping. Reference numeral 25 denotes a regulating plate that prevents earth and sand cut out of the hopper 4 from spilling out from the conveyor 5.

  The aforementioned nutrient supply device 6 supplies a liquid nutrient, and is provided with a supply pipe 27 (details will be described later) having a plurality of holes for spreading the nutrient on the side surface. The supply pipe 27 is supported by a frame 26 that spans the regulating plate 25 of the conveyor 5 and the inlet 35 of the mixing device 7. Although not shown in FIG. 16, as shown in FIG. 15, the present system includes a pump unit 28 that supplies nutrients to the supply pipe 27.

  The pump unit 28 includes a storage tank 29 that stores the nutrient, a pump 30 that discharges the nutrient stored in the storage tank 29, a connection line 32 that connects the storage tank 29 and the supply pipe 27, and the connection pipe. And an on-off valve 33 provided in the passage 32. The pump unit 28 may be configured separately or integrally with the soil improvement machine 200.

  15 and 16, the additive supply device 39 includes a storage tank 40 that stores powdered additives such as microbial materials, adsorbents, and improving materials, and an additive in the storage tank 40 downward. It is composed of a feeder 41 to be derived.

  The storage tank 40 includes a bottomed cylindrical lower tank part 42, a bellows-like upper tank part 43 connected to the upper part thereof, and an upper cover 44 of the upper tank part 43. By configuring the upper tank portion 43 in a bellows shape in this way, the storage tank 40 can be expanded and contracted vertically. For example, when the soil improvement machine 200 is transported, the storage tank 40 is contracted and the total height is reduced. Consideration is given to ensure that the height is sufficient to meet transportation restrictions.

  The feeder 41 is a so-called rotary feeder, and is not particularly shown for preventing congestion, but has a built-in rotor in which a plurality of partition walls project radially on the rotating shaft, and is introduced into the space between the partition walls from the storage tank 40. The additives are sequentially added to the earth and sand on the conveyor 5. However, in the present embodiment, the feeder 41 is a rotary feeder, but the present invention is not limited to this and may be a screw feeder.

  The mixing device 7 is mounted approximately on the center in the longitudinal direction (left and right direction in FIG. 16) of the main body frame 10, and an inlet 35 (see FIG. 18) of earth and sand and additive on the upper side of one side (left side in FIG. 16). ) Is provided at the lower part of the other side (right side in FIG. 16) with an outlet (not shown) of the treated soil. Although not shown for preventing congestion, the mixing device 7 has at least one paddle mixer provided substantially in parallel, and the introduced earth and sand and the additive are uniformly stirred and mixed by the paddle mixer. While processing, it is transferred to the outlet side, and the treated soil is led out from the outlet. A drive device 36 drives the paddle mixer.

  The discharge conveyor 8 is a discharge unit that conveys the treated soil discharged from the mixing device 7 and discharges it to the outside of the machine. The discharge conveyor 8 is a predetermined distance from below the outlet (not shown) of the mixing device 7 toward the other side (right side in FIG. 16). After extending substantially horizontally, the driving device 36 of the mixing device 7 extends upward from below. Reference numeral 37 denotes a frame of the discharge conveyor 8. The conveyor frame 37 is supported from the power unit 9, the main body frame 10, and the like by a support member (not shown).

  Although not specifically shown, the power unit 9 is an engine as a power source of the drive device of each device described above, a hydraulic pump driven by the engine, and pressure oil supplied from the hydraulic pump to the drive device of each device. A plurality of control valves and the like to be controlled are built in, and supported by a support member 38 at the other end (right side in FIG. 16) in the longitudinal direction of the main body frame 10.

Next, the operation of this system will be described.
First, when the earth and sand excavated by the hydraulic excavator 100 is put into the sieve device 3 of the soil improvement machine 200, large stones and rubble are removed by the lattice member 15, and the earth and sand components that have passed through the lattice member 15 are introduced into the hopper 4. The By this classification, the particle size distribution of the earth and sand is made uniform and the size is easily mixed with the additive. Further, when the lattice member 15 vibrates, the soil block larger than the eyes of the lattice member 15 is jumped up and falls again on the lattice member 15. By repeating such an operation, the earth lump is crushed by the impact at that time and the edge effect of the mesh (or blade) of the lattice member 15, and the one smaller than the mesh of the lattice 15 is introduced into the hopper 4. .

  The earth and sand in the hopper 4 is placed on the conveyor 5 while being stirred and crushed by the arch breaker 18 to prevent crosslinking. Thus, the earth and sand placed on the conveyor 5 are cut out by a fixed amount outside the hopper 4 through the opening 4a of the hopper 4 (see FIG. 18). Additives are supplied to the earth and sand conveyed to the mixing device 7 by the conveyor 5 by the nutrient supply device 6 and the additive supply device 39.

  At this time, when the system is used to mix microorganisms, nutrients, adsorbents, and the like with the excavated soil to generate sediment material in the pollutant decomposition zone, the nutrient supply device 6 supplies the nutrients. Then, the microorganisms and the adsorbent are supplied by the additive supply device 39. When no nutrient is added, only the additive supply device 39 needs to be operated. The microbial material is stored in the storage tank 40, and if necessary, the adsorbent is mixed with the microbial material. Further, if a liquid microbial carrier is used, the microorganisms can be supplied by the nutrient supply device 6. Conversely, when only the nutrient is added, only the nutrient supply device 6 needs to be operated, and when the adsorbent is added, the adsorbent is stored in the storage tank 40, and the nutrient supply device 6, The additive supply device 39 supplies nutrients and adsorbents, respectively.

  On the other hand, when this system is used for the purification process of mixing the improved material into the excavated contaminated soil to volatilize and remove the contaminated material, the nutrient supply device 6 is stopped and the improved material is supplied by the additive supply device 39. Just do it. In this case, the nutrient supply device 6 may be omitted.

  The earth and sand introduced into the mixing device 7 as described above are uniformly stirred and mixed in the mixing device 7 together with the additive. The treated soil (or soil material in the pollutant decomposition zone) mixed by the mixing device 7 is led out onto the discharge conveyor 8, transported by the transport conveyor 8, and discharged outside the machine. Then, the treated soil (or the soil material in the pollutant decomposition zone) discharged from the soil improvement machine 200 is backfilled at a predetermined location by the excavator 100.

  If this system is used, the sand is uniformly stirred by the mixing device 7, so that the excavated earth and sand are mixed with microorganisms, nutrients, adsorbents, etc., to generate sediment material for the pollutant decomposition zone, The workability of the purification process of mixing the improved material with the excavated contaminated soil to volatilize and remove the pollutant to produce treated soil is improved as compared with the case of mixing with the hydraulic excavator 100, and the earth and sand and additives are sufficient. And can be mixed.

  Also in this system, since the soil improvement machine 200 has a self-propelled function, it is easy to change the layout of the system, move within the site, transport, and the like. Further, since the system is configured only by the hydraulic excavator 100 and the soil improvement machine 200, the system itself is also compact. Therefore, it is possible to construct a system by effectively using the space at the contamination site, and it does not take time to carry in, carry out, disassemble and assemble the system, ensuring high workability and shortening the construction period.

  Further, in the present system, the soil improvement machine 200 is arranged at the rear stage of the excavator 100, but even if a simple stationary mixing device is used instead of the soil improvement machine 200, the mixing state of the earth and sand is uniform. Sexual effects can be secured. In this case, the system can be further downsized.

  FIG. 19 is a side view showing the overall structure of another example of a system suitable for constructing each embodiment of the soil contamination countermeasure method of the present invention. In FIG. 19, the same parts as those in the previous drawings are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 19, the present system is composed of a hydraulic excavator 100 for loading earth and sand, and two soil improvement machines 200 and 300 for mixing additives into the received earth and sand. Also in this example, as means for supplying earth and sand to the soil improvement machine 200, the excavator 100 may be replaced with, for example, a belt conveyor or a screw conveyor.

  This system is mainly used to produce sediment materials in the pollutant decomposition zone, for example, adding multiple additives, ie nutrients, microbial materials, adsorbents, and other release agents as needed. In this case, it is suitable for the case where the types of additives mixed by the two soil conditioners 200, 300 are separated. The types of additives mixed by the two soil improvement machines 200 and 300 are not limited, and the additives may be divided into any combination.

  Moreover, the main structure of the soil improvement machine 300 is the same as that of the soil improvement machine 200, and in FIG. 19, the same code | symbol is attached | subjected to the part similar to the soil improvement machine 200, and description is abbreviate | omitted. However, since the gravel and the like are removed by the sieve device 3 in the former soil conditioner 200 in the latter soil conditioner 300, the sieve device 3 of the soil modifier 300 is omitted in this system. Moreover, in the soil improvement machines 200 and 300, when any one of the nutrient supply device 6 and the additive supply device 39 is not used, a configuration in which they are omitted may be employed.

  Hereinafter, as an example, after mixing the nutrient and microbial material into the earth and sand in the former soil conditioner 200, the adsorbent is further mixed in the latter soil conditioner 300, thereby the soil material constituting the pollutant decomposition zone. The operation of this system when it is generated will be described.

  In this case, first, the earth and sand excavated by the hydraulic excavator 100 is put into the sieve device 3 of the soil improvement machine 200. The earth and sand thrown into the sieving device 3 is guided to the hopper 4, stirred by the arch breaker 18, and conveyed via the conveyor 5. On the way, the nutrient solution and the microorganism material are added by the nutrient supply device 6 and the additive supply device 39, respectively, and introduced into the mixing device 7. And the earth and sand are uniformly mixed in the mixing device 7 together with the nutrient and the microbial material, and supplied to the soil improvement machine 300 via the discharge conveyor 8.

  The mixed soil from the soil improver 200 received by the hopper 4 of the soil improver 300 is transported by the transport conveyor 5 and introduced into the mixer 7 together with the adsorbent from the additive supply device 39. The mixed soil introduced into the mixing device 7 is uniformly stirred and mixed together with the adsorbent by the paddle mixer, and is discharged onto the discharge conveyor 8 as a sediment material constituting a pollutant decomposition zone. Then, the earth and sand material is carried out of the apparatus on the discharge conveyor 8 and backfilled at a predetermined position by the hydraulic excavator 100 to form a pollutant decomposition zone.

  Also in this embodiment, the same effect as that of the system shown in FIG. 16 is obtained, and the earth and sand are mixed with the additive in two steps using the two soil improvement machines 200 and 300, so that a more uniform condition is obtained. A mixed soil material can be created. Of course, in this example, as long as the earth and sand are uniformly stirred, even if the soil improvement machines 200 and 300 are not necessarily used, only two mixing devices are used, and the target earth and sand are added to the additives together with the additives. You may make it perform a mixing process.

  FIG. 20 is a side view showing the overall structure of still another example of a system suitable for implementing each embodiment of the soil contamination countermeasure method of the present invention. In FIG. 20, the same parts as those in the previous drawings are denoted by the same reference numerals, and description thereof is omitted.

The system shown in FIG. 20 is different from the system shown in FIG. 19 in that a mixed soil supply device 250 is disposed between the soil conditioners 200 and 300, and the other points are the same as those in the system of FIG. It is the same.
Also in this system, as means for supplying earth and sand to the soil improvement machine 200, instead of the hydraulic excavator 100, for example, a belt conveyor or a screw conveyor may be substituted. Further, the soil improvement machines 200 and 300 may be replaced with a simple mixing device.

  In FIG. 20, the mixed soil supply device 250 is a hopper 251 as a storage container that receives the mixed soil from the soil improvement machine 200 and temporarily stores the mixed soil, and a supply unit that supplies the mixed soil in the hopper 251 to the soil improvement machine 300. And a conveyor 252. The hopper 251 has an arch breaker 253 with substantially the same configuration as the hopper 4 of the soil improvement machines 200 and 300. Reference numeral 254 denotes a support member that supports the conveyor 252. In this system, the mixed soil supply device 250 is a stationary facility, but the lower portion of the conveyor 252 is supported by a vehicle body (travel device) instead of the support member 254. A self-propelled conveyor may include a hopper 251 with an arch breaker 253.

  In this system, the same effect as the system shown in FIGS. 16 and 19 can be obtained, and by adding the mixed soil supply device 250, the mixed soil from the soil improvement machine 200 can be further stirred, It is possible to further uniformly stir and mix the additive.

  In addition, in the three systems described in FIGS. 15 to 20, the case where the earth and sand are mixed by the mixing device having the paddle mixer has been described, but the configuration and type of the mixing device are not particularly limited, and the mixing device is not necessarily limited. For example, other types of mixing devices such as a screw mixer may be used, and mixing means such as a stabilizer may be applied. Furthermore, it is not necessarily limited to mixing by a machine, and depending on the amount of treated soil, soil may be mixed manually.

  Furthermore, in the above description, the traveling devices 45 and 102 of the excavator 100 and the soil improvement machines 200 and 300 are crawler type equipped with the endless track crawler belts 49 and 101. The traveling device may be used. Further, if not particularly necessary, the traveling device 45 of the soil improvement machines 200 and 300 may be omitted. Furthermore, the sieve device 3 and the tilt 17 of the soil improvement machine 200 can be omitted if not necessary, and conversely, the sieve device 3 and the tilt 17 may be provided in the soil improvement machine 300 if necessary. In these cases, the same effect is obtained.

It is a longitudinal cross-sectional view showing one construction example of 1st Embodiment of the pollution countermeasures of this invention. It is a horizontal sectional view by the II-II section in FIG. It is a longitudinal cross-sectional view showing the construction example of 2nd Embodiment of the pollution countermeasures of this invention. It is a horizontal sectional view by the IV-IV section in FIG. It is a longitudinal cross-sectional view showing the construction example of 3rd Embodiment of the contamination countermeasure method of this invention. It is a horizontal sectional view by the VI-VI cross section in FIG. It is a longitudinal cross-sectional view of an example of the site used as construction object of 4th Embodiment of the pollution control method of this invention. It is a longitudinal cross-sectional view showing the construction example of 4th Embodiment of the pollution countermeasures of this invention. It is a longitudinal cross-sectional view of an example of the site used as construction object of 5th Embodiment of the pollution countermeasure method of this invention. It is explanatory drawing of the construction procedure of the pollution countermeasure method of 5th Embodiment of the pollution countermeasure method of this invention. It is explanatory drawing of the construction procedure of the pollution countermeasure method of 5th Embodiment of the pollution countermeasure method of this invention. It is explanatory drawing of the construction procedure of the pollution countermeasure method of 5th Embodiment of the pollution countermeasure method of this invention. It is a longitudinal cross-sectional view of an example of the site used as construction object of 6th Embodiment of the pollution countermeasure method of this invention, and a longitudinal cross-sectional view of 1 construction example of 6th Embodiment of the pollution countermeasure method of this invention. It is a perspective view showing the whole structure of the excavation heavy machine which is an example of an apparatus suitable for constructing the soil contamination countermeasure method of this invention. It is the block diagram which extracted and represented the principal part of an example of the system suitable for constructing the soil contamination countermeasure method of this invention. It is a side view showing the whole structure of an example of a system suitable for constructing the soil pollution countermeasure method of this invention. It is a side view showing the detailed structure of the sieve apparatus with which the soil improvement machine which comprises an example of a suitable system for constructing the soil pollution countermeasure method of this invention, and the hopper vicinity. It is a figure showing the detailed structure of the downstream vicinity of the conveyance conveyor with which the soil improvement machine which comprises an example of the system suitable for constructing the soil contamination countermeasure method of this invention was equipped. It is a side view showing the whole structure of the other example of the system suitable for constructing each embodiment of the soil pollution countermeasure method of this invention. It is a side view showing the whole structure of the further another example of the system suitable for constructing each embodiment of the soil pollution countermeasure method of this invention.

Explanation of symbols

b Pollutant i Pollutant decomposition zone j Boundary g High concentration distribution region k, l Pipe q Treated soil layer

Claims (7)

A procedure to investigate in advance the distribution of pollutants, soil quality, geological gradient, and groundwater level gradient in the site to be treated ;
The procedure to identify the direction of movement of pollutants from the results of this preliminary survey,
Sediment obtained by excavating the site along the boundary with the adjacent land adjacent to the site on the downstream side of the moving direction of the pollutant based on the specified direction of movement of the contaminant. The earth and sand material mixed with at least one of microorganisms that decompose pollutants or nutrients that activate microorganisms is backfilled in the excavated area, and pollutants that enter the area are selectively collected and decomposed and removed. And a procedure for forming a pollutant decomposition zone.   After excavating the high-concentration distribution area of the pollutant investigated above, the excavated soil is mixed with lime or an improved material containing lime-based chemicals to purify the pollutant, and then the treated soil is buried in the excavation site. The pollution control method according to claim 1, wherein the pollution control method is returned.   The pollution control method according to claim 1, wherein an adsorbent that adsorbs the pollutant is mixed with the earth and sand material constituting the pollutant decomposition zone.   The pollution control method according to any one of claims 1 to 3, wherein the pollutant decomposition zone is formed so as to cover a height range of an existing region of the pollutant remaining in the ground.   The pollution control method according to any one of claims 1 to 4, wherein a pipe for injecting air or a nutrient is inserted in or near the pollutant decomposition zone.   6. The pollution control method according to claim 1, wherein a pipe for injecting nutrients or microorganisms is inserted at a position upstream of the pollutant decomposition zone in the moving direction. The pollutant distribution, soil quality, stratum gradient, and groundwater level gradient have been investigated in advance. In case of inclination,
The pollutant is purified by excavating contaminated soil on its own site and mixing it with lime or lime-based chemicals.
After forming the pollutant decomposition zone in the part of the adjacent land side in the location where the pollutant is excavated, the pollutant of the adjacent land as a decomposition target,
The pollution control method according to claim 1, wherein the processing soil mixed with the chemical is backfilled in a remaining part of the site where the pollutant is excavated.

Images