JP4055076B2 - Contaminated soil purification equipment - Google Patents

Description

  The present invention relates to a contaminated soil purification method and apparatus for purifying contaminated soil at the same position with oils or volatile organic compounds.

  Conventionally, pollutants such as oils and volatile organic compounds infiltrate into the soil due to the dumping of industrial waste and the discharge of industrial wastewater, thereby contaminating the soil. When the soil is contaminated, the contaminants are eluted into the groundwater, so that the soil contamination and the groundwater contamination spread over a wide area, which may affect the living environment. Therefore, soil environment standards and groundwater purification standards are established by the Basic Environment Law and the Water Pollution Control Law, and various substances are regulated.

  Therefore, various efforts have been made for these contaminated soils. Conventionally, there is a purification method in which contaminated soil or groundwater is recovered by soil excavation, pumping, or soil gas extraction, and then the contaminant is separated and processed. Moreover, many purification methods in which a substance or microorganism that promotes decomposition directly into contaminated soil is injected and decomposed are employed, and a method that combines injection and pumping is also used.

  In particular, in the contaminated soil purification method disclosed in Patent Document 1, by forming an iron powder-containing layer filled with iron powder in the lateral direction in the soil, groundwater flowing through the iron powder-containing layer and the soil and / or Or it contacts with soil moisture and the organic halogen compound in soil and / or groundwater is decomposed. Thereby, contaminated soil and groundwater can be purified relatively cheaply and efficiently in a short period of time.

Moreover, in the groundwater purification structure and the groundwater purification method disclosed in Patent Document 2, a wall-like region (water-permeable wall) composed of a mixture of iron powder, iron oxide, and iron hydroxide is formed in the vertical direction in the ground. By providing in, groundwater contaminated with arsenic can be effectively purified.
JP 2002-28631 A JP 2003-39080 A

  However, with conventional soil excavation, purification methods using water pumping or extraction of soil gas, facilities for separating and treating the collected soil, groundwater, or gas must be provided and separated. Therefore, the equipment space and equipment cost for this increase. In addition, the method of purifying by injection has a problem that it takes a lot of time for purification. The method of purifying by combining water injection and pumping can reduce the time required for purification, but it is necessary to provide a facility for separating and processing after pumping, and the facility space and facility cost for separating and processing Will increase.

  Even in the purification methods of Patent Document 1 and Patent Document 2, since the groundwater flow existing in the soil is used, the contaminated soil purification method requires a lot of time, and the flow of groundwater is likely to fluctuate due to various factors. If it deviates from the groundwater flow, the problem arises that the contaminated soil cannot be purified.

  The present invention has been made in view of such circumstances, and it is possible to actively purify contaminated soil without groundwater veins without providing facilities necessary for separation and treatment of contaminants on the ground surface. An object of the present invention is to provide an excellent contaminated soil purification method and apparatus that can be effectively performed in a short time.

Pumping to claim 1 of the present invention to achieve the object, by injecting a chemical solution or water from water injection wells in the ground of the contaminated soil was treated with pollutants contained in the soil, the drug solution or water and the treatment In the contaminated soil purification apparatus for pumping water from the well, the pumping well has vertical holes excavated in the vertical direction from the ground surface to the contaminated soil, and a large number of the chemical liquid or water that is inserted into the vertical holes and flows downward into the vertical holes. A cylindrical member in which a hole is formed, a mesh member provided around the cylindrical member to prevent clogging of the hole, and a catalyst or an adsorbent between the wall of the vertical hole and the cylindrical member And a treatment layer that supports the cylindrical member and treats the contaminants by being filled with a sand material mixed with.

In the pumping well according to claim 1, a cylindrical member covered with a net member is loosely inserted into a vertical hole excavated in a vertical direction from the ground surface to the contaminated soil, and a catalyst or an adsorbent is interposed between the vertical hole and the net member. A treated layer is formed by filling the mixed sand material, and the cylindrical member is supported in the vertical hole by the treated layer.

  When pumping is started in the pumping well, the chemical solution or water injected into the contaminated soil is taken into the cylindrical member through the sand material layer and the net-like member, and pumped to the ground surface. Since the treatment layer is formed by mixing a catalyst or an adsorbent with sand material having good water permeability, the incorporated chemical solution or water can be passed efficiently. In addition, since the chemical liquid or water to be pumped always passes through the treatment layer until it is taken into the cylindrical member, when it passes, it comes into contact with the catalyst or adsorbent contained in the treatment layer and removes remaining contaminants. It can be decomposed or adsorbed efficiently. Therefore, since no pollutants already remain in the chemical solution or water in the cylindrical member, it is not necessary to separate and treat the pollutants with respect to the chemical solution or water after pumping. Time, facility space, facility cost, and running cost for separation and processing on the ground surface can be greatly reduced. In addition, by providing a highly water-permeable mesh member around the outer periphery of the cylindrical member, sand material of the sand material layer, catalyst or adsorbent flows into the numerous holes provided in the cylindrical member during pumping. Since clogging can be prevented, water can be pumped stably and efficiently.

  Thus, since the pumping well is configured with a simple structure by performing the treatment in the treatment layer, the contaminated soil can be purified efficiently in a short time, and the installation time and equipment cost can be further reduced. Can be reduced.

Claim 2 of this invention inject | pouring a chemical | medical solution or water from the well for water injection into the contaminated soil in the ground, processing the pollutant contained in soil, and the contaminated soil pumping up the processed chemical | medical solution or water from the well for pumping In the purification apparatus, the pumping well is a cylinder in which a vertical hole excavated in a vertical direction from the ground surface to the contaminated soil, and a plurality of holes that are loosely inserted into the vertical hole and from which the chemical solution or water flows out are formed below. A cylindrical member, a processing net provided around the cylindrical member to prevent clogging of the holes and containing a catalyst or adsorbent component for processing the contaminants, the wall of the vertical hole, and the cylinder And a sand material layer filled with sand material to support the cylindrical member.

The pumping well according to claim 2 is configured such that a cylindrical member covered with a catalyst net is loosely inserted into a vertical hole excavated in a vertical direction from the ground surface to the contaminated soil, and a sand material is interposed between the vertical hole and the cylindrical member. It is formed by providing a sand material layer filled with and supporting the cylindrical member and the processing member in the vertical hole.

  When pumping is started in the pumping well, the chemical solution or water injected into the contaminated soil passes through the sand material layer, the processing member, and the processing net, and then enters the cylindrical member from a number of holes provided in the cylindrical member. It is taken in and pumped to the surface.

  Since the sand material layer is composed of sand material having high water permeability, the incorporated chemical solution or water can be efficiently transmitted.

  In addition, by providing a treatment net on the outer periphery of the cylindrical member, it prevents clogging of the hole of the cylindrical member due to the inflow of sand during pumping, and the chemical solution or water that has treated or washed contaminated soil passes. In this case, the remaining contaminants can be decomposed or adsorbed for treatment by contacting with the catalyst or adsorbent contained in the treatment net.

  Since the chemical liquid or water to be pumped up always passes through the treatment net before being taken into the cylindrical member, the chemical liquid or water taken into the cylindrical member does not contain any contaminants. Therefore, since it is not necessary to separate and treat the pollutant on the ground surface after pumping the ground surface, the time, facility space, facility cost, and running cost for separation and treatment on the ground surface can be greatly reduced. In addition, since the pumping well has a relatively simple structure, it is possible to further reduce installation time and equipment cost, and to efficiently clean contaminated soil in a short time.

  As described above, in the contaminated soil purification method and apparatus according to the present invention, pumping water on the ground surface is provided by providing a well for injection and a well for pumping and a processing member for processing the pollutant in the pumping well. It is possible to efficiently purify contaminated soil without incurring equipment space for separation and treatment, equipment costs, and running costs for separation. In addition, since a catalyst or adsorbent having a high processing speed is used as a processing member and injection is performed in an injection well having a degassing means, it is possible to purify contaminated soil efficiently in a very short time.

  As a result, the contaminated soil can be purified reliably and inexpensively without taking time and effort for installation, and therefore, a wide range of contaminated soil can be purified in a short time.

  Hereinafter, preferred embodiments of a contaminated soil purification method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional perspective view showing a schematic configuration of a contaminated soil purification apparatus 10 according to a first embodiment of the present invention, which is an example in which a chemical solution is injected into a contaminated soil for purification. In this embodiment, an organic halogen compound and oil are described as contaminants contained in the contaminated soil, and an aqueous solution to which hydrogen peroxide is added is injected from a water injection well to oxidize and decompose the contaminants. An example in which contaminants remaining in a chemical solution are treated with catalyst titanium oxide in a pumping well will be described below.

  As shown in FIG. 1, the contaminated soil purification apparatus 10 is mainly configured such that a plurality of water injection wells 12, 12... And a plurality of pumping wells 14, 14.

  Each of the water injection wells 12, 12... And each of the pumping wells 14, 14... Is formed by excavating vertically from the surface 18 to a depth reaching the contaminated soil 16 contaminated by the pollutant.

  In addition, a water injection tank 20 for storing a chemical to be injected is provided around the surface of the water injection well 12 on the surface. The water injection tank 20 is connected to a water injection pump 22 for supplying a chemical solution for injection and a water injection pipe 24. The water injection tank 20 is always filled with water through each of the water injection wells 12, 12... The drug solution is filled and injected. On the other hand, a pumping tank 28 for storing the chemical liquid pumped to the ground surface is provided around the pumping well 14. The pumping tank 28 is provided with a pumping pump 30 for sucking the chemical solution in the contaminated soil 16, and pumped by being connected to the pumping wells 14, 14.

  The water injection well 12 includes a pipe 34 as a cylindrical member, a silica sand layer 36 as a sand material layer, and a net 38 as a net member. The pipe 34 is made of a water-resistant material such as vinyl chloride, and the length of the pipe 34 is preferably the same as the depth of the water injection well 12. A large number of holes are provided in the surface of the pipe 34 in the same range as the thickness of the contaminated soil 16. For the silica sand layer 36, silica sand, which is a sand material with good water permeability, is used. The silica sand layer 36 is formed by filling silica sand between the water injection well 12 and the pipe 34. The net 38 is made of a net-like material and is installed so as to cover the outer periphery of the pipe 34. It is preferable that the mesh of the net 38 is of a size that does not hinder water permeability and that the silica sand of the silica sand layer 36 can be prevented from flowing into the pipe 34.

  FIG. 2 is a sectional view of the pumping well 14 in the contaminated soil purification apparatus 10 according to the first embodiment of the present invention. As shown in FIG. 2, the structure of the pumping well 14 is substantially the same as that of the water injection well 12, but a treatment member 40 is provided between the silica sand layer 36 and the net 38. The treatment member 40 is formed by filling titanium oxide, which is a catalyst, with water.

  Next, the effect | action in the contaminated soil purification apparatus 10 which is the 1st Embodiment of this invention mentioned above is demonstrated.

  In the contaminated soil purification apparatus 10, when the chemical solution is constantly poured from the water injection tank 20 to the water injection pit 26 via the water injection pipe 24, the water injection wells 12, 12,... Are always filled. Since the top surface of the water injection pit 26 is open, even if a gas such as air exists or is generated in each of the water injection wells 12, 12..., The water injection pit 26 is deaerated as it is. For this reason, the fall of the water injection efficiency of water injection well 12,12 ... by the resistance of gas can be prevented.

  When the chemical solution is filled in the pipe 34 provided in the water injection well 12 in this way, the chemical solution is leached from a large number of holes provided in the pipe 34 and permeates into the contaminated soil 16 through the net 38 and the silica sand layer 36. . Since the net 38 and the silica sand layer 36 have water permeability, the chemical solution can be effectively permeated and diffused from the water injection well 12 to the contaminated soil 16 in a short time. Then, the injected chemical solution and the contaminant contained in the contaminated soil 16 come into contact with each other to cause an oxidation reaction, and the contaminant in the contaminated soil 16 can be decomposed.

  The chemical solution that decomposes the pollutant is pumped through the pumping well 14 by the suction force of the pump 30. Then, the chemical solution in the contaminated soil 16 passes through the silica sand layer 36 provided in the pumping well 14, the treatment member 40, and the net 38 and is taken into the pipe 34 provided in the pumping well 14. At this time, the chemical solution and the processing member 40 come into contact with each other, and hydrogen peroxide in the chemical solution reacts with titanium oxide in the processing member 40, thereby generating radicals having strong oxidizing power. Since the contaminants remaining in the chemical solution can be reliably decomposed by the radicals generated in this manner, the contaminants can be almost removed from the chemical solution taken into the pipe 34. Therefore, since there is no pollutant in the chemical liquid sucked up to the surface 18 through the pipe 34 as pumped water, it can be discharged as it is through the pumped tank 28, so that the water is pumped as in the conventional case. Later, facilities for separating and treating pollutants on the ground surface are no longer necessary, and the facility space and facility costs for that purpose can be greatly reduced. Furthermore, since water injection and pumping are performed in combination, the contaminated soil can be purified efficiently, and the time and running cost required for purification can be further reduced.

  In the contaminated soil purification apparatus 10 described above, titanium oxide is used as the treatment member 40, but there is no particular limitation, and iron or a mixture of iron and titanium oxide may be used as a catalyst. Alternatively, water may be used instead of the chemical solution, and an adsorbent such as activated carbon or ion exchange resin may be used as the processing member 40 instead of the catalyst. Thereby, the contaminated soil 16 is washed by injecting water from the water injection well 14 in the contaminated soil purification apparatus 10. Then, by sucking the washed water from the pumping well 14, it comes into contact with the adsorbent which is the processing member 40 provided in the pumping well 14. Then, since the contaminants in the water are adsorbed by the physical attraction of the adsorbent of the processing member 40 and removed from the water, the water treated by the processing member 40 is pumped up to the ground surface 18 through the pipe 34, and the pumping pipe 32, the pumping pump 30, and the pumping tank 28 can be discharged as they are.

  FIG. 3 is a cross-sectional view of a pumping well 50 in the soil contamination purification apparatus according to the second embodiment of the present invention, and is an example in which a treatment net is provided.

  The configuration of the soil contamination purification apparatus is the same as that of the contaminated soil purification apparatus 10 according to the first embodiment of the present invention. However, as shown in FIG. In addition, a catalyst net 52 made of titanium oxide is provided as a treatment net.

  According to the contaminated soil purification apparatus of the second embodiment of the present invention, the chemical solution in the contaminated soil 16 passes through the silica sand layer 36, the catalyst net 52, and the pipe 34 by a suction force from a pumping pump (not shown). The water is pumped from the pumping well 50. When passing through the catalyst net 52, radicals having a strong oxidizing power are generated in contact with the titanium oxide of the catalyst net 52, and the contaminants contained in the washed water are effectively decomposed and removed by the radicals. be able to. Accordingly, the contaminants can be decomposed and removed only by pumping, and the number of members provided in the pumping well 50 can be reduced, so that the equipment cost for the pumping well 50 can be further reduced. In addition, the labor required for installing the pumping well 50 can be saved.

  FIG. 4 is a cross-sectional view of the pumping well 60 in the contaminated soil purification apparatus according to the third embodiment of the present invention, and is an example in which a treatment layer is provided.

  The apparatus configuration of the contaminated soil purification apparatus is the same as that of the contaminated soil purification apparatus 10 according to the first embodiment of the present invention, but as shown in FIG. A catalyst layer 62 is provided as a treatment layer. The catalyst layer 62 is formed by filling between the pipe 34 and the pumping well 60 with silica sand mixed with an appropriate amount of titanium oxide as a catalyst.

  According to the contaminated soil purification apparatus of the third embodiment of the present invention, the washed water contained in the contaminated soil 16 is converted into the catalyst layer 62, the net 38, and the pipe by a suction force from a pump not shown. 34, the water is pumped from the pumping well 60. When passing through the catalyst layer 62, the hydrogen peroxide in the chemical solution comes into contact with the titanium oxide in the catalyst layer 62 to form radicals having a strong oxidizing power. Since the contaminants remaining in the chemical solution can be effectively decomposed by the radicals, the contaminants can be removed simply by pumping water. Moreover, since the catalyst layer formed by mixing titanium oxide with silica sand can serve both for supporting the pipe and treating the chemical solution, the facility cost in the pumping well 60 can be further reduced, and the contact area with the chemical solution Therefore, pollutants can be decomposed and removed more efficiently.

  In the contaminated soil purification apparatus 10 and the pumping wells 14, 50, 60 described above, the number, shape, material, and the like of each member and apparatus are not particularly limited.

  In the contaminated soil purification apparatus 10, water injection and pumping are performed in separate systems, but there is no particular limitation. Returning the pumped chemical to the water injection side as it is, adjusting the chemical to an appropriate concentration and using it, can reduce the amount of water used to purify the contaminated soil 16, greatly reducing the running cost of purification. can do.

  In addition, in the water injection to each of the water injection wells 12, 12..., The water injection pit 26 is used as a degassing means. If the pipes 34, 34... Of each of the water injection wells 12, 12... And the water injection pipe 24 are directly connected and a valve as a degassing means is provided in the water injection pipe 24, it exists in the water injection wells 12, 12,. Since gas can be extracted by a valve and the pressure of water injection can be adjusted, highly efficient water injection can be performed.

  Furthermore, although the silica sand layer 36 formed of silica sand is used as the sand material layer, it is not particularly limited. Any material that has good permeability to the chemical solution and / or water and can stably support and fix the pipe 34 may be used.

The cross-sectional perspective view which showed schematic structure of the contaminated soil purification apparatus which is the 1st Embodiment of this invention. Sectional drawing of the pumping-side well in the contaminated soil purification apparatus which is the 1st Embodiment of this invention Sectional drawing of the pumping-side well in the contaminated soil purification apparatus which is the 2nd Embodiment of this invention Sectional drawing of the pumping-side well in the contaminated soil purification apparatus which is the 3rd Embodiment of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Contaminated soil purification apparatus, 12 ... Water injection well, 14 ... Pumping well, 16 ... Contaminated soil, 18 ... Ground surface, 20 ... Water injection tank, 22 ... Water injection pump, 24 ... Water injection piping, 26 ... Water injection pit, 28 DESCRIPTION OF SYMBOLS ... Pumping tank, 30 ... Pumping pump, 32 ... Pumping piping, 34 ... Pipe, 36 ... Silica sand layer, 38 ... Net, 40 ... Treatment member, 50 ... Water well for pumping, 52 ... Catalyst net, 60 ... Water well, 62 ... Catalyst layer

Claims (2)

In the contaminated soil purification apparatus for injecting chemical liquid or water from the water injection well into the underground contaminated soil to treat the pollutant contained in the soil, and pumping the treated chemical liquid or water from the pumping well,
The pumping well is
A vertical hole excavated longitudinally from the ground surface to the contaminated soil;
A cylindrical member that is loosely inserted into the vertical hole and has a plurality of holes formed in the lower part thereof through which the chemical solution or water flows out.
A mesh member provided around the cylindrical member to prevent clogging of the hole;
A treatment layer that supports the tubular member and treats the contaminants by filling a sand material mixed with a catalyst or an adsorbent between the wall of the vertical hole and the tubular member. Contaminated soil purification device characterized by that. In the contaminated soil purification apparatus for injecting chemical liquid or water from the water injection well into the underground contaminated soil to treat the pollutant contained in the soil, and pumping the treated chemical liquid or water from the pumping well,
The pumping well is
A vertical hole excavated longitudinally from the ground surface to the contaminated soil;
A cylindrical member that is loosely inserted into the vertical hole and has a plurality of holes formed in the lower part thereof through which the chemical solution or water flows out.
A treatment net that is provided around the cylindrical member to prevent clogging of the holes and contains a catalyst or adsorbent component that treats the contaminants;
A contaminated soil purification apparatus comprising: a sand material layer filled with sand material between the wall of the vertical hole and the cylindrical member to support the cylindrical member.

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