JP2023138432A - Structure, and structure construction method - Google Patents

Abstract

To provide a structure 10 or the like that can purify soil without installing a well again.SOLUTION: A structure comprises: a microorganism carrier material 17 capable of carrying microorganisms; a first tube (outer tube 11) which has the microorganism carrier material 17, is embedded underground, and into which ground water can flow from a side face; and a second tube (ground water monitoring pipe 12) for monitoring ground water in the first tube, where a microbial preparation input hole 14 is formed at a position where microorganisms can be supplied to the microorganism carrier material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structure and a structure construction method.

When soil at a construction site or the like is contaminated with pollutants, soil purification work is carried out. For example, Patent Document 1 describes a contaminated soil purification system applying a soil purification method, which includes an injection process in which a solution of iron powder and organic matter mixed with hot water is injected into underground soil from an injection well, and A soil purification method is disclosed that includes a recovery step of recovering a solution to the ground together with groundwater.

JP2021-090927A

Typically, pairs of injection wells and collection wells for purification are moved at predetermined intervals to sequentially purify the soil. However, in monitoring wells, high-concentration contamination such as a contamination plume (pool of contaminated undiluted solution) may unexpectedly appear during the purification process. If injection wells and recovery wells were reinstalled near monitoring wells where high concentrations of contamination appeared, there were problems that would lead to delays in construction and increased costs.

Therefore, the present invention has been made in view of the above-mentioned problems, etc., and one example of the problem is a structure that can purify soil without installing a well again even if a high concentration of contamination occurs. The purpose is to provide

In order to solve the above problems, the invention according to claim 1 has a microorganism supporting material capable of supporting microorganisms, and the microorganism supporting material is embedded in the ground so that groundwater in the ground can be internalized from the side. a first pipe into which the groundwater can flow, a second pipe for monitoring the groundwater within the first pipe, and a microbial preparation inlet hole into which the microbial preparation containing the microorganism is introduced; The microorganism is characterized in that the hole is formed at a position where the microorganism can be supplied to the microorganism supporting material.

Moreover, the invention according to claim 2 is characterized in that the microbial preparation inlet hole is formed outside the first tube.

Further, the invention according to claim 3 is characterized in that the first pipe and the microbial preparation input hole are surrounded by a screen material having a diameter larger than the diameter of the microorganism carrier material. .

Further, the invention according to claim 4 is characterized in that a protection tube is provided, which has the first tube and the microbial preparation injection hole therein, and surrounds and protects the screen material from surrounding soil.

Further, the invention according to claim 5 is characterized in that the microbial preparation inlet hole is formed inside the first tube.

Moreover, the invention according to claim 6 is characterized in that a part of the side surface of the microbial preparation injection hole is formed by the inner surface of the first tube.

Moreover, the invention according to claim 7 is characterized in that the microorganism supporting material is silica having fine voids.

Further, the invention according to claim 8 is characterized in that the first tube includes a third tube for feeding air.

Further, the invention according to claim 9 is the structure according to claim 1 or 5, characterized in that the second pipe has a fourth pipe for recovering the substance to be treated in the groundwater.

The invention according to claim 10 also provides a first pipe installation step of installing a first pipe in the dug hole through which underground water can flow into the inside from the side, and an inner part of the first pipe. a second pipe installation step of installing a second pipe for monitoring the groundwater; a microbial preparation injection hole forming step of forming a microbial preparation injection hole at a position where microorganisms can be supplied to the microorganism carrier material; The method is characterized by including a step of filling the microorganism carrier material inside the tube and outside the second tube with the microorganism carrier material.

According to the present invention, there is provided a microorganism-carrying material capable of carrying microorganisms, a first pipe having the microorganism-carrying material, which is embedded in the ground and allows underground water to flow into the inside from the side, and an inner part of the first pipe. and a second pipe for monitoring groundwater in the groundwater, and the microbial preparation injection hole is formed in a position where microorganisms can be supplied to the microorganism carrier material, so that when the concentration of contamination increases due to monitoring of the groundwater, Again, it is possible to provide a structure or the like that can purify soil without installing a well.

FIG. 1 is a front view showing an example of a schematic configuration of a structure according to a first embodiment. 2 is a plan view showing an example of a schematic configuration of the structure shown in FIG. 1. FIG. FIG. 2 is a perspective view showing an example of a schematic configuration of the structure shown in FIG. 1. FIG. 2 is a schematic diagram showing an example of installation of the structure shown in FIG. 1. FIG. 7 is a flowchart illustrating an example of a structure construction operation according to the first embodiment. It is a flowchart which shows an example of operation|movement of soil purification in a structure. It is a schematic diagram which shows the modification of the installation of a structure. It is a schematic diagram which shows the modification of the installation of a structure. FIG. 7 is a front view showing an example of a schematic configuration of a structure according to a second embodiment. 10 is a plan view showing an example of a schematic configuration of the structure shown in FIG. 9. FIG. 7 is a flowchart illustrating an example of a structure construction operation according to the second embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are embodiments in which the present invention is applied to a structure.

(First embodiment)
[1. Configuration and functional overview of structure according to first embodiment]

First, the configuration and general functions of a structure according to a first embodiment of the present invention will be explained using FIGS. 1 to 3.

FIG. 1 is a schematic diagram showing an example of a schematic configuration of a structure according to a first embodiment. FIG. 2 is a plan view showing an example of a schematic configuration of the structure. FIG. 3 is a perspective view showing an example of the general configuration of the structure.

As shown in FIGS. 1 and 2, the structure 10 according to the first embodiment includes an outer pipe 11 embedded in the ground below the ground G, a groundwater monitoring pipe 12 for monitoring groundwater w, and an outer pipe 11 embedded in the ground below the ground G. A bubbling pipe 13 for supplying air into the inside of the pipe 11, a microbial preparation injection hole 14 for introducing a microbial preparation containing microorganisms, a collection pipe 15 for collecting a liquid to be removed such as oil, and a collection pipe 15 for supplying air to the collection pipe 15. It includes an air supply pipe 16 for supplying air lift, and a microorganism support material 17 capable of supporting microorganisms.

A screen material 18 such as cobblestones or crushed stones is filled between the inner wall of the well WL dug from the ground G and the outside of the outer pipe 11. The outer pipe 11 has the function of a protection pipe that protects the inside of the outer pipe 11 from the earth and sand of the well WL.

FIG. 1 schematically shows a case of complex contamination between a treatment object o1 whose specific gravity is lighter than water and a treatment object o2 whose specific gravity is heavier than water. The object to be processed o1 is, for example, mineral oil such as petroleum. The object to be treated o2 is, for example, volatile organic compounds (VOCs), such as trichlorethylene, which have a higher specific gravity than water. Note that the groundwater w itself may be contaminated with organic phosphorus, organic nitrogen, and the like.

The outer tube 11 is an example of a first tube that has a microorganism support material 17 and is buried underground so that underground water w can flow into the inside from the side. As shown in FIG. 3, the outer tube 11 has, for example, a plurality of holes 11a on the side surface. Underground water (W), etc. flows into the hole 11a. A nonwoven fabric 14b is installed inside the outer tube 11 to prevent the screen material 18 and dirt from entering the outer tube 11 through the hole 11a. A metal or resin net may be used instead of the nonwoven fabric 14b. The size of the gravel that is the screen material 18 is preferably larger than the hole 11a. A mesh material is wrapped around the outside of the outer tube 11. The mesh material is, for example, a metal or resin net, and the mesh is about 2 mm. This mesh material prevents the microorganism support material 17 inside the outer tube 11 and the screen material 18 outside the outer tube 11 from entering.

The diameter of the outer tube 11 is about 100 [mm]. For example, the inner diameter of the outer tube 11 is 107 [mm] and the outer diameter is 114 [mm]. The length of the outer pipe 11 is long enough to reach the water-blocking layer underground. Note that the diameter of the well W in the boring survey is about 150 [mm]. The inner diameter of the outer tube 11 may be large enough to accommodate the groundwater monitoring pipe 12, bubbling pipe 13, and microbial preparation injection hole 14, and to accommodate a predetermined amount of microbial support material 17 necessary for purification. The thickness of the outer tube 11 depends on the material of the outer tube 11, but may be any thickness that will not be damaged by pressure from the outside or the inside of the outer tube 11.

The material of the outer tube 11 may be metal or concrete, but resin such as vinyl chloride is preferable.

The groundwater monitoring pipe 12 is an example of a second pipe for monitoring groundwater w within the outer pipe 11. The groundwater monitoring pipe 12, which is the inner pipe of the outer pipe 11, has a plurality of holes 12a on the side surface. The shape of the hole 12a is, for example, slit-like or circular. Groundwater w and the like flow into the interior through these holes 11a. The shape and size of the hole 12a should be such that the microorganism carrier material 17 does not enter from around the groundwater monitoring pipe 12.

The outer diameter of the groundwater monitoring pipe 12 is about 50 [mm], which is smaller than the inner diameter of the outer tube 11 and is sufficient as long as it is large enough to form the bubbling pipe 13 and the microbial preparation injection hole 14 inside the outer tube 11. The inner diameter of the groundwater monitoring pipe 12 may be large enough to allow the collection pipe 15 and the air lift pipe 16 to be inserted into the groundwater monitoring pipe 12 .

The length of the groundwater monitoring pipe 12 is approximately the same as the length of the outer pipe 11. Further, the bottom surface of the groundwater monitoring pipe 12 is closed with a cap 12b to prevent the mud pool md from entering from the bottom.

The material of the groundwater monitoring pipe 12 is preferably resin such as vinyl chloride.

The bubbling pipe 13 is an example of a third pipe for sending air into the outer tube 11. The diameter of the bubbling pipe 13 is about 20 [mm]. The length of the bubbling pipe 13 is long enough to reach the layer of groundwater w. Air is supplied from the tip 13a of the bubbling pipe 13 to the microorganism supporting material 17 within the outer tube 11. The bubbling pipe 13 is preferably made of resin such as vinyl chloride.

As shown in FIGS. 2 and 3, the microbial preparation inlet hole 14 is formed by the partition member 14a and the inner surface of the outer tube 11. In this way, a part of the side surface of the microbial preparation injection hole 14 is formed by the inner surface of the outer tube 11. This is an example in which the microbial preparation injection hole is formed at a position where microorganisms can be supplied to the microorganism carrier material.

The partition member 14a is formed, for example, by dividing a pipe smaller in diameter than the outer tube 11 in half in the longitudinal direction. The partition member 14a prevents the microorganism carrier material 17 from entering the microorganism preparation injection hole 14. The partition member 14a may have a diffusion hole so that the microorganisms introduced into the microbial preparation injection hole 14 can diffuse into the outer tube 11. Note that the partition member 14a is not limited to a semicircular shape, but may be U-shaped. Note that the microbial preparation injection hole 14 may be a perforated pipe having a diameter that allows the introduction of a drug containing microorganisms. It is sufficient if microorganisms can be additionally introduced through the microbial preparation injection hole 14.

As shown in FIG. 3, a nonwoven fabric 14b is installed on the inner surface of the outer tube 11. The nonwoven fabric 14b prevents dirt from entering through the holes 11a of the outer tube 11. The microorganisms introduced into the microbial preparation injection hole 14 are diffused into the soil around the outer tube 11 through the holes 11a of the outer tube 11 through the nonwoven fabric 14b.

The depth of the microbial preparation injection hole 14 is, for example, up to the vicinity of the water level of the groundwater w. Since the water level of groundwater w changes, the position of the water level of groundwater w is only a guide. The bottom of the microbial preparation inlet hole 14 may be closed. If the bottom of the microbial preparation inlet hole 14 is blocked, microorganisms will easily spread from the sides of the microbial preparation inlet hole 14.

The recovery pipe 15 is an example of a fourth pipe that recovers the object to be treated from the groundwater w in the groundwater monitoring pipe 12. The diameter of the recovery pipe 15 is about 20 [mm], which is smaller than the inner diameter of the groundwater monitoring pipe 12 and can be inserted into the groundwater monitoring pipe 12. The tip of the collection tube 15 is cut diagonally so that the object to be processed can be easily collected.

The air lift pipe 16 supplies air from near the tip of the recovery pipe 15. The recovery pipe 15 and the air supply pipe 16 can be moved up and down within the groundwater monitoring pipe 12.

Since the collection pipe 15 and the air supply pipe 16 move up and down within the groundwater monitoring pipe 12, the material of the collection pipe 15 and the air supply pipe 16 may be flexible resin except for the tip portions.

The microorganism supporting material 17 is a material having fine voids, such as silica having fine cracks such as joints or porous silica. Microorganisms are supported in the fine voids of minerals such as silica. The particle size of the microorganism-carrying material 17 may be a size that allows the underground water w to pass through the outer pipe 11 smoothly. The shape of the microorganism supporting material 17 may be sand-like or pebble-like.

Here, the supported microorganisms include bacteria that can decompose oil such as petroleum, such as Psuedomonas, Acinetobacter, and Rhodococcus. Examples of microorganisms for degrading chloroethylene include bacteria of the genus Dehalobacter, Dehalococcoides, and Desulfitobacterium. The supported microorganisms may be aerobic or anaerobic microorganisms.

These microorganisms are injected from the microbial preparation inlet 14 as a microbial preparation, which is a mixed solution of nutrients, minerals, and the like. The microbial preparation, which is a purification agent, may contain bentonite or the like to give it viscosity.
[2. Operation example regarding the structure according to the first embodiment]
(2.1 Operation example of constructing a structure according to the first embodiment)
Next, an example of the operation of constructing the structure 10 will be explained using the drawings.

FIG. 4 is a schematic diagram showing an example of installation of the structure 10. FIG. 5 is a flowchart illustrating an example of the construction operation of the structure 10 according to the embodiment.

First, in a site as shown in FIG. 4, a plurality of investigation wells 20 for boring investigation are dug. The depth of the investigation well 20 is, for example, up to the impermeable layer b. If there is a building 21, an investigation well 20 is also dug around it.

Groundwater from each investigation well 20 is sampled and the state of contamination is examined. Based on the inspection results, the investigation well 20 in which the structure 10 is to be set is specified. In particular, the structure 10 is installed in a research well 20 near a location where the concentration of pollutants is high or a location where the impermeable layer is depressed. Furthermore, a water stop plate 22 may be installed around the area where the soil is to be purified to prevent the substances to be treated from spreading.

The diameter of the investigation well 20 in which the structure 10 is constructed is, for example, about 150 [mm].
The diameter of the investigation well 20 may be about 150 [mm] from the beginning, or after the investigation well 20 for constructing the structure 10 is identified, the diameter of the hole may be expanded to about 150 [mm]. .

As shown in FIG. 5, the outer tube 11 is installed in the investigation well 20 (step S1). Specifically, it is inserted into the hole of the investigation well 20. Note that the hole 11a inside the outer tube 11 at the portion where the microbial preparation injection hole 14 is formed is closed with a nonwoven fabric 14b.

Next, the screen material 18 is filled (step S2). Specifically, a screen material 18 such as cobblestones is placed around the outer tube 11, and the screen material 18 is packed to fix the position of the outer tube 11.

Next, the groundwater monitoring pipe 12 and bubbling pipe 13 are installed (step S3). Specifically, a groundwater monitoring pipe 12 and a bubbling pipe 13 are inserted into the hole of the outer pipe 11 and set up.

Next, the microorganism support material 17 is added (step S4). Specifically, the microorganism supporting material 17 is placed inside the outer pipe 11 around the groundwater monitoring pipe 12 and the bubbling pipe 13. The microorganism supporting material 17 is introduced to a level above the groundwater w or to a depth corresponding to the length of the partition member 14a. Microorganism carrier material 17 is packed inside the outer pipe 11, outside the groundwater monitoring pipe 12, and outside the bubbling pipe 13.

Next, the partition member 14a is installed (step S5). Specifically, the partition member 14a is installed on the side of the outer tube 11 on which the nonwoven fabric 14b is stretched. A microbial preparation inlet hole 14 is formed by the partition member 14a and a part of the inside of the outer tube 11.

Next, the remaining microorganism-carrying material 17 is added (step S6). Specifically, inside the outer pipe 11, the microorganism-carrying material 17 is placed around the groundwater monitoring pipe 12, bubbling pipe 13, and partition member 14a. The microorganism carrier material 17 is introduced up to the ground surface. A microorganism carrier material 17 is filled inside the outer tube 11 , outside the groundwater monitoring pipe 12 , outside the bubbling pipe 13 , and outside the microorganism preparation injection hole 14 .

As shown in FIG. 3, the outer tube 11 may be covered with clay or bentonite so as to hide the screen material 18. By covering with clay or bentonite, earth and sand can flow into the screen material 18 and prevent clogging between the screen materials 18.

(2.2 Example of soil purification operation)
Next, an example of soil purification operation will be explained using diagrams.
FIG. 6 is a flowchart showing an example of the soil purification operation in the structure 10.

First, after the structure 10 is installed in each predetermined investigation well 20, an injection well and a recovery well are installed on the site within the water stop plate 22, and the soil is purified in order at approximately 2 m intervals. . Specifically, a bubbling device or the like is connected to the bubbling pipe 13 in the structure 10 . Air is supplied to the microorganisms on the microorganism support material 17 through the bubbling pipe 13 . Further, to purify the soil, the objects to be treated o1 and o2 are collected, and a microbial preparation containing microorganisms is introduced.

As shown in FIG. 6, a water quality test is performed in the structure 10 (step S10). Specifically, groundwater w near the water level, near the bottom of the outer pipe 11, etc. is extracted from the groundwater monitoring pipe 12 of the structure 10, and a water quality test is performed. The condition of the microorganism support material 17 is confirmed from the number of microorganisms, underground water temperature, amount of dissolved oxygen, etc. Water quality testing may also be performed in the investigation well 20 where the structure 10 is not installed.

Next, according to the results of the water quality test, the objects to be treated are collected and the microbial preparation is introduced (step S11). Specifically, in the case of a structure 10 in which a predetermined amount or more of the substance to be treated such as o1 is found as a result of a water quality test, the collection pipe 15 and the air lift pipe 16 are connected to the groundwater monitoring pipe 12 of the structure 10, Insert until you see w. Air is sent into the recovery pipe 15 from the air supply pipe 16 connected to a bubbling device or the like, and the underground water w and the object to be treated o1 are pumped up by the bubbles. In addition, when the object to be treated o2 is more than a predetermined value, the collection pipe 15 and the air lift pipe 16 are inserted into the groundwater monitoring pipe 12 to the vicinity where the object to be treated o2 is located. By operating the structure 10, the objects to be treated o1 and o2 are collected through the collection pipe 15 and the air supply pipe 16.

If the condition of the microbial support material 17, such as the number of microorganisms and the degree of bioactivity, is confirmed as a result of the water quality test and it becomes necessary to introduce microorganisms, a microbial preparation containing microorganisms is poured into the microbial preparation injection hole 14. It will be done.

When the microbial preparation is introduced, the microorganisms diffuse into the outer tube 11 through the partition member 14a of the microbial preparation injection hole 14, and the microorganisms diffuse into the soil outside through the hole 11a of the outer tube 11.

As described above, water quality will be purified by monitoring the water quality and repeating the collection of harmful substances and the injection of microbial preparations.

According to the structure 10 according to the first embodiment, the structure 10 includes a microorganism supporting material 17 that can support microorganisms, and is embedded in the ground so that underground water w can flow into the inside from the side. It includes an outer pipe 11, a groundwater monitoring pipe 12 for monitoring groundwater in the outer pipe 11, and a microbial preparation injection hole 14 formed in the outer pipe 11 into which a microbial preparation containing microorganisms is introduced. By doing this, when the concentration of contamination increases as a result of monitoring groundwater, the soil can be purified without having to install a well again.

When a part of the side surface of the microbial preparation injection hole 14 is formed by the inner surface of the outer tube 11, microorganisms are more likely to diffuse into the ground from the side surface of the outer tube 11, and water quality purification is promoted.

When the microorganism-carrying material 17 is silica having fine voids, the microorganisms are retained in the voids and the effect of the microorganisms lasts longer.

When the outer tube 11 includes a bubbling pipe 13 for feeding air, aerobic microorganisms are more activated.

When the groundwater monitoring pipe 12 includes a recovery pipe 15 for recovering the objects o1 and o2 to be treated in the groundwater w, the objects o1 and o2 to be treated can be recovered to promote soil purification.

(Modified example)
Next, a modification of the installation of the structure 10 will be explained using the drawings. Note that the same reference numerals are used for the same or corresponding parts as in the above embodiment, and only different configurations and operations will be explained. FIGS. 7 and 8 are schematic diagrams showing modifications of the installation of the structure 10.

As shown in FIG. 7, when it is desired to purify the soil under the embankment 30, the structure 10 may be constructed by digging a tunnel 31 horizontally and digging a vertical hole at the back of the tunnel 31 up to the impermeable layer b. .

As shown in FIG. 8, the structure 10 may be constructed by digging a hole diagonally from the side of the embankment 30 to the bottom of the embankment 30. Note that the inclination of the recovery tube 15 is preferably as close to vertical as possible, and the outer tube 11 and the recovery tube 15 do not necessarily have to be parallel.

(Second embodiment)
[3. Configuration, functional overview, and operation of structure according to second embodiment]
(3.1 Structure and functional overview of structure according to second embodiment)
Next, a second embodiment will be described using FIGS. 9 to 11. Note that the same reference numerals are used for the same or corresponding parts as in the first embodiment, and only different configurations and operations will be described. The same applies to other embodiments and modifications.

FIG. 9 is a front view showing an example of a schematic configuration of a structure according to the second embodiment. FIG. 10 is a plan view showing an example of the general configuration of the structure.

As shown in FIGS. 9 and 10, the structure 10A according to the second embodiment includes a perforated pipe 11A buried in the ground below the ground G, and protection that protects the structure 10A from the soil around the hole. Pipe 11B, groundwater monitoring pipe 12, bubbling pipe 13, microbial preparation input pipe 14A for introducing microbial preparation, recovery pipe 15, air supply pipe 16, microorganism support material 17 capable of supporting microorganisms, and microorganism support material 17. A screen material 18 which is crushed stone or the like having an average diameter larger than the average diameter of the material 17 is provided.

The perforated pipe 11A, which is an example of the first pipe, is almost the same as the outer pipe 11 except that it does not have the microbial preparation inlet hole 14 inside the perforated pipe 11A.

The dimensions of the perforated pipe 11A may be the same as the outer pipe 11, and the diameter of the perforated pipe 11A is about 100 [mm], and the length of the perforated pipe 11A is long enough to reach the underground water barrier layer. be.

As shown in FIG. 9, the perforated tube 11A has a plurality of holes on the side surface, similarly to the outer tube 11 of the first embodiment. Similar to the outer tube 11, a mesh is provided on the outside of the perforated pipe 11A to prevent the microorganism-carrying material 17 from leaking from the hole 11a and to prevent the screen material 18 and soil from entering into the perforated pipe 11A. The material is wrapped.

The perforated tube 11A has a microorganism support material 17. The inside of the perforated pipe 11A around the groundwater monitoring pipe 12 and the bubbling pipe 13 installed in the perforated pipe 11A is filled with a microorganism supporting material 17.

A microbial preparation input pipe 14A, which is an example of a microbial preparation injection hole, is installed surrounded by a screen material 18 on the outside of the perforated pipe 11A. This is an example in which the microbial preparation injection hole is formed at a position where microorganisms can be supplied to the microorganism carrier material. Furthermore, this is an example in which the microbial preparation inlet hole is formed outside the first tube. Further, this is an example in which the first pipe and the microbial preparation injection hole are surrounded by a screen material having a diameter larger than the diameter of the microorganism carrier material.

The material of the microbial preparation input pipe 14A, which is an example of the microbial preparation injection hole, is a pipe made of resin such as vinyl chloride. The microbial preparation input tube 14A has a diameter of about 30 [mm] and a length of about 500 [mm]. The microbial preparation input tube 14A may have a perforated side surface so that microorganisms can easily penetrate therein.

The microbial preparation input pipe 14A is installed surrounded by a screen material 18 on the outside of the perforated pipe 11A.

The protection tube 11B has a perforated tube 11A and a microbial preparation input tube 14A inside, and surrounds the screen material to protect it from surrounding soil. The protection tube 11B has a diameter of about 200 [mm].

The length of the protection tube 11B is somewhat longer than the length of the microbial preparation input tube 14A. When a predetermined amount or more of a liquid microbial preparation is injected from the proximal port of the microbial preparation input pipe 14A coming out from the ground G, it disturbs the surrounding soil, moves the soil toward the screen material 18, and causes the surrounding ground to disturb. To avoid the possibility of subsidence, as shown in FIG. 9, the length of the protective tube 11B is made longer than the length of the microbial preparation input tube 14A, and it is installed so that it is deeper than the tip of the microbial preparation input tube 14A. It is preferable.

As with the outer tube 11, the material of the protective tube 11B may be metal or concrete, but resin such as vinyl chloride is preferable.

The protection tube 11B protects the perforated pipe 11A and the microbial preparation input pipe 14A so that surrounding soil does not flow between the perforated pipe 11A and the microbial preparation input pipe 14A and reduce water permeability due to heavy rain. do. Further, as shown in FIG. 9, the protection tube 11B is installed a little higher than the ground G with the proximal end of the protection tube 11B protruding so that the structure 10A will not be submerged in water. The protruding length of the protective tube 11B is changed depending on the surrounding environment.

A screen material 18 is filled around the perforated tube 11A and the microbial preparation input tube 14A. A screen material 18 is also installed around the protective tube 11B so as to fill the gap between it and the inner surface of the excavated hole. The screen material 18 packed around the protection tube 11B may be different in particle size, material, etc. from the screen material 18 filled in the protection tube 11B.

(3.2 Operation example regarding structure according to second embodiment)
Next, an example of the operation of constructing the structure 10A will be explained using the drawings.

FIG. 11 is a flowchart illustrating an example of the construction operation of the structure 10A according to the second embodiment.

Similar to the structure 10 according to the first embodiment, as shown in FIG. 11, the shaft of the investigation well 20 for boring investigation is bored by a boring machine to a depth that reaches the impermeable layer b (S20). If the outer diameter of the protection tube 11B is 200 [mm], the diameter of the hole required to construct the structure 10A is, for example, 250 to 300 [mm] because the outside is filled with crushed stone, soil, etc. after the protection tube 11B is inserted. ] That's about it. The diameter of the investigation well 20 may be approximately 250 to 300 [mm] from the beginning, or after the investigation well 20 for constructing the structure 10A is identified, the diameter of the hole may be expanded to 250 to 300 [mm]. It's okay.

Next, while pulling out the boring rod, the protection tube 11B is built into the soil (S21).

Next, the perforated pipe 11A is built into the hole of the investigation well 20 and inside the protection pipe 11B, and the process of pulling out the protection pipe 11B to a predetermined depth while filling it with screen material 18 such as crushed stone is repeated (S22).

Next, the above operations are repeated, and when a predetermined depth is reached, the microbial preparation input tube 14A is inserted and the screen material 18 is filled (S23).

Next, the groundwater monitoring pipe 12 and the bubbling pipe 13 are built to a predetermined depth inside the perforated pipe 11A, and the microorganism supporting material 17 is filled with care for the arrangement (S24).

Next, a synthetic pipe in which the air supply pipe 16 is fixed to the recovery pipe 15 is inserted inside the groundwater monitoring pipe 12 to a predetermined depth (S25). Note that the predetermined depth varies depending on the type of contaminant.

Next, the designed filling amounts of the screen material 18 and the microorganism-carrying material 17 are checked, and it is confirmed that there are no remaining high amounts (S26). Specifically, the remaining screen material 18 is introduced and filled into the inside of the protective tube 11B outside the perforated tube 11A and the microbial preparation input tube 14A. The microorganism supporting material 17 is introduced into the perforated pipe 11A outside the groundwater monitoring pipe 12 and the bubbling pipe 13 to fill it. Here, "staying at a high level" means that some kind of filling failure occurs when filling the microorganism support material 17 or screen material 18 from the top of the tube, creating a large void, and the pre-calculated amount cannot be filled. It's about the situation.

Note that the operation example of soil purification is the same as that in the first embodiment. If the results of the water quality test indicate that it is necessary to introduce microorganisms, a predetermined amount of a microbial preparation containing microorganisms is poured into the microbial preparation injection pipe 14A.

When the microbial preparation is introduced, the microbial preparation flows down from the microbial preparation injection pipe 14A and spreads onto the screen material 18 around the microbial preparation injection pipe 14A. The microorganisms spread on the screen material 18 enter the inside of the perforated pipe 11A through the holes 11a of the perforated pipe 11A, and are supplied to the microorganism supporting material 17. Furthermore, microorganisms diffuse from the screen material 18 into the surrounding soil.

According to the structure 10A according to the second embodiment, the structure includes a microorganism supporting material 17 that can support microorganisms, and a microorganism supporting material 17 that is embedded in the ground and allows underground water to flow into the inside from the side. It includes a perforated pipe 11A and a groundwater monitoring pipe 12 for monitoring groundwater within the perforated pipe 11A, and a microbial preparation input pipe 14A is formed at a position where microorganisms can be supplied to the microorganism carrier material 17. This makes it possible to provide a structure that can purify soil when the concentration of contamination increases through groundwater monitoring, without having to install a well again.

When the microbial preparation input tube 14A is formed outside the perforated tube 11A, the microorganism support material 17 that can be filled inside the perforated tube 11A is inserted into the perforated tube 11A. It becomes more than . Moreover, since the microbial preparation injection tube 14A is used as is, rather than forming the microbial preparation injection hole 14 using a part of the inner wall surface of the outer tube 11, the formation of the microbial preparation injection hole is easier and the cost is reduced.

When the perforated tube 11A and the microbial preparation input tube 14A are surrounded by a screen material 18 having a diameter larger than the diameter of the microorganism support material 17, microorganisms with some solid matter in the microbial preparation input tube 14A When the preparation is injected, the microbial preparation input tube 14A is less likely to be clogged, and more microbial preparation can be supplied. In addition, microorganisms easily diffuse through the screen material 18 having a larger particle size than the microorganism supporting material 17 into the microorganism supporting material 17 inside the perforated pipe 11A and the soil around the structure 10A.

When a protective tube 11B is provided, which has a perforated tube 11A and a microbial preparation input tube 14A therein, and surrounds the screen material 18 to protect it from surrounding soil, it is possible to prevent earth and sand from flowing in due to rain or the like. When constructing the structure 10A, the soil on the side walls of the drilled hole is less likely to collapse during the work, making the construction work easier.

10, 10A: Structure 11: Outer tube (first tube)
11A: Perforated pipe (first pipe)
12: Groundwater monitoring pipe (second pipe)
14: Microbial preparation inlet hole 14A: Microbial preparation inlet pipe (microbial preparation inlet hole)
17: Microorganism support material 18: Screen material

Claims (10)

a microorganism-supporting material capable of supporting microorganisms;
a first pipe having the microorganism-carrying material and being buried underground so that the groundwater underground can flow into the inside from the side;
a second pipe for monitoring the groundwater within the first pipe;
a microbial preparation injection hole into which a microbial preparation containing the microorganism is introduced;
Equipped with
A structure characterized in that the microbial preparation injection hole is formed at a position where the microorganism can be supplied to the microorganism support material. The structure according to claim 1, wherein the microbial preparation inlet hole is formed outside the first tube. 3. The structure according to claim 2, wherein the first tube and the microbial preparation input hole are surrounded by a screen material having a diameter larger than the diameter of the microorganism support material. 4. The structure according to claim 3, further comprising a protection tube that has the first tube and the microbial preparation inlet hole therein, and that surrounds and protects the screen material from surrounding soil. The structure according to claim 1, wherein the microbial preparation inlet hole is formed in the first tube. 6. The structure according to claim 5, wherein a part of the side surface of the microbial preparation injection hole is formed by the inner surface of the first tube. 7. The structure according to claim 1, wherein the microorganism supporting material is silica having fine voids. 6. The structure according to claim 1, further comprising a third pipe for feeding air into the first pipe. 6. The structure according to claim 1, further comprising a fourth pipe within the second pipe that collects the substance to be treated from the groundwater. a first pipe installation step of installing a first pipe in the dug hole so that underground groundwater can flow into the inside from the side;
a second pipe installation step of installing a second pipe for monitoring the groundwater within the first pipe;
a microbial preparation injection hole forming step of forming a microbial preparation injection hole at a position where microorganisms can be supplied to the microorganism support material;
a microorganism carrier filling step of filling the inside of the first tube and the outside of the second tube with the microorganism carrier;
A structure construction method characterized by comprising:

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