JP2008093499A - Polluted soil purifying method and soil pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a homogenous and sufficiently strong soil pile embedded in polluted soil, and a method for certainly purifying polluted soil using the soil pipe. <P>SOLUTION: The soil panel 1 is constituted by connecting pile units 10, each of which is constituted by filling a nonwoven fabric bag 11 having a definite length and a doughnut cross section with a filler 12 such as sand, sawdust, etc. mixed with pollutant decomposing microorganisms and by compacting the same by a perforated tube 13 arranged in the hole parts of the nonwoven fabric bag 11 and provided with a large number of through holes 13h, and embedded in the soil (polluted area) K present in the ground just under a site where a building is constructed and the polluted soil of the polluted area is purified by the pollutant decomposing action of microorganisms. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for purifying a contamination source such as soil or groundwater containing a contaminant, and a soil pile used for the method.

Conventionally, as a method for purifying contaminated soil containing pollutants such as heavy oil and organic solvents, purified water containing microorganisms that decompose the pollutants is supplied to an area where the contaminated soil is present, and decomposed by the microorganisms. A method for purifying the contaminated soil by decomposing the pollutant has been proposed (for example, see Patent Documents 1 and 2).
4 (a) and 4 (b) are diagrams showing an example of a conventional contaminated soil purification system 50. Here, the contaminated soil purification system 50 is contaminated with a volatile organic chlorine compound existing at a position lower than the groundwater level W1 in a natural state. Soil (hereinafter referred to as a contaminated area) M is purified. Specifically, purified water containing pollutant-decomposing microorganisms stored in the decomposition liquid tank 51 is supplied to the contaminated area M through the injection pipe 52, and a pumping facility is provided below the contaminated area M. 53 is installed and a negative pressure is given using the suction pump 55 via the pipe 54 connected to the nozzle hole of this pumping equipment 53, and thereby groundwater is sucked from the nozzle hole. As a result, the groundwater level W1 can be lowered to a position W2 that is lower than the contaminated area M to be purified, and the decomposition area N into which the purified water is injected can be expanded, so that the contaminated area M is efficiently purified. be able to.
At this time, while supplying the fungus active liquid containing the microorganism activating substance housed in the fungus active liquid tank 56 to the contaminated area M together with the purified water containing the pollutant-decomposing microorganisms, If an air supply pipe 59 connected to a pump 58 is attached to a sand column 57 made of gravel that covers the injection pipe 52 and the pumping equipment 53, fresh air is sent to the decomposition region N. Since the microorganisms in the decomposition region N can be activated, the contaminated region M can be purified more efficiently.
Japanese Patent Laid-Open No. 9-276837 JP-A-9-276840

However, in the above conventional purification system, only the injection pipe 52 supplies purified water containing pollutant-decomposing microorganisms to the contaminated area M. Therefore, depending on the distribution state of the groundwater flow, the decomposed area N can be sufficiently widened. There is a problem that it is not possible.
Further, since the injection pipe 52 and the pumping equipment 53 need to be constructed immediately above the contaminated area M, it is difficult to apply the purification system when there is a building or the like above the contaminated area M. .
On the other hand, when there is a building at the upper part of the contaminated area M, a casing is drilled from, for example, an induction horizontal boring machine from a position away from the building, and pollutant decomposing microorganisms are contained in the casing. Although a method of constructing a soil pile in the contaminated area M by pulling out the casing after pushing the filler is considered, this method not only makes it difficult to construct a homogeneous pile, but also the density of the soil pile is reduced. There was a risk of attracting land subsidence due to the low and soft pile.

  The present invention has been made in view of the conventional problems, and provides a soil pile having a uniform and sufficient strength embedded in contaminated soil and a method for reliably purifying the contaminated soil using the soil pile. With the goal.

The invention according to claim 1 of the present application is to produce a pile unit containing a filler mixed with microorganisms that decompose pollutants in a non-woven bag of a predetermined length, and these pile units are connected to each other by the pile. After connecting using a perforated tube inserted into the filler of the unit and having a large number of holes on its side, the connected pile unit is pre-embedded in soil containing contaminants After inserting into the area where the contaminated soil exists through the inside of the guided pipe, pull out the guide pipe to build a soil pile in the contaminated soil, and the contamination due to the decomposing action of microorganisms in the filler It is intended to purify the soil.
The invention according to claim 2 is the method for purifying contaminated soil according to claim 1, wherein the non-woven bag is a non-woven bag having an annular cross section, and the perforated tube is passed through the hole of the non-woven bag. The pile units are connected to each other.
According to a third aspect of the present invention, in the method for purifying contaminated soil according to the first or second aspect, when the guide pipe is pulled out, the soil pile and the excavation hole wall in which the guide pipe is embedded are provided. This space is filled with a filler.
According to a fourth aspect of the present invention, in the method for purifying contaminated soil according to the third aspect, the guide pipe is a guide pipe formed by connecting a plurality of steel pipes, and the length of the pile unit is the length of the steel pipe. It is the same length as the length.
The invention according to claim 5 is a soil pile comprising a filler mixed with microorganisms for decomposing the pollutant, which is constructed in soil containing the pollutant, and has a predetermined length for storing the filler. And a perforated tube that is inserted into each of the above-mentioned cloth bags for connecting the plurality of non-woven bags.

According to the present invention, when purifying soil containing pollutants using microorganisms that decompose pollutants, a pile unit is prepared that contains a filler mixed with the microorganisms in a non-woven bag of a predetermined length. In addition, after connecting the pile units to each other through a perforated tube for supplying purified water containing air or the microorganisms to the pile units, the connected pile units are placed in the contaminated soil in advance. Inserted into the area where the contaminated soil exists through a guide pipe formed by connecting a plurality of buried steel pipes, then pulls out the guide pipe to construct a soil pile in the contaminated soil, Since the contaminated soil is purified by the decomposing action of the microorganisms, the contaminated soil can be purified efficiently and reliably.
In the present invention, the pile unit and the connected unit are prepared in advance at the site or factory, so that not only a uniform pile unit can be produced, but also compaction is possible. So you can build a strong soil pile.
In addition, since the soil pile of the present invention is a pile unit connected, if the perforated tube is made of a flexible material, the connecting portion of the tube is made bellows, or a joint whose angle can be adjusted is used, Even a long object can be bent or folded, so that it is not only easy to handle but also easy to insert into a guide tube.
Furthermore, when the guide pipe is pulled out, if the space between the soil pile and the excavation hole wall in which the guide pipe is embedded is filled with a filler such as sand, ground subsidence can be reliably prevented. be able to. At this time, if the length of the pile unit is the same as the length of the steel pipe, the filling material can be filled simultaneously with the drawing of the steel pipe, so that the filling material can be reliably filled. .

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
FIGS. 1A and 1B are diagrams showing a configuration of a soil pile 1 according to the best mode. This soil pile 1 is embedded in the contaminated area K to purify the contaminated soil. A fixed length nonwoven fabric bag 11 is filled with a filler 12 such as sand or sawdust mixed with pollutant-degrading microorganisms. It is obtained by connecting a plurality of compacted pile units 10. In this example, the nonwoven fabric bag 11 is a bag having a donut-shaped cross section, and the pile units 10 are connected to each other through a perforated tube 13 provided with a large number of through holes 13h on the side surface. At this time, if the connecting portion of the perforated tube 13 is made of a flexible material or is made bellows, it can be bent or folded even if the length of the soil pile 1 is increased. Easy to handle. The entire perforated tube 13 may be made of a flexible material, or a joint whose angle can be adjusted may be used for the connecting portion of the perforated tube 13.
The pile unit 10 and the pile pile 1 connecting the pile units 10 can be prepared in advance at the site or factory, so that not only the uniform pile unit 10 can be prepared, but also each pile unit 10 is compacted. Therefore, it has sufficient strength to withstand earth pressure.

Moreover, FIG. 2 is a figure which shows schematic structure of the purification system 20 of the contaminated soil using the said soil pile 1, In this example, contamination of the heavy oil etc. which exist in the ground directly under the site | part with the buildings T, such as a factory, is shown. A case where the soil (hereinafter referred to as a contaminated area) K containing a substance is purified will be described.
The contaminated soil purification system 20 in this example supplies air to a plurality of rows of soil piles 1 embedded in a contaminated region K and the pollutant-decomposing microorganisms mixed in the filler 12 through the perforated tube 13. A blower device 21, a microorganism storage tank 22 that stores purified water containing pollutant-decomposing microorganisms, a supply pipe 23 that connects the blower device 21, the microorganism storage tank 22, and the perforated tube 13, And a water blocking wall 24 constructed around the contaminated area K, and purifies the contaminated soil in the contaminated area K by the pollutant decomposing action of the pollutant-decomposing microorganisms mixed in the filler 12. At the same time, the microorganisms are activated by air from the blower 21. Further, if necessary, the purified water is sent from the microorganism storage tank 22 to the soil pile 1 to replenish the pollutant-decomposing microorganisms and promote the purification of the contaminated area K.
In this example, the supply of air and the supply of purified water are performed together by a single supply pipe 23, but they may be provided separately.

Next, the construction method of the soil pile 1 will be described.
First, as shown in FIG. 3A, a guide tube 30 for disposing the soil pile 1 is embedded in the contaminated area K. The guide tube 30 is formed by connecting a plurality of steel pipes 31 having a predetermined length. As an embedding method, an inner tube in which a drilling device is attached to a buried outer tube and a tip inserted into the outer tube is used. A well-known curved boring in which the outer pipe and the inner pipe are simultaneously pushed and buried while excavating a natural ground using a double pipe made of a pipe is preferably used.
After the drilling, the inner pipe and the excavator are collected, and then the soil pile 1 is inserted into a guide pipe 30 as an outer pipe and sent to a predetermined position as shown in FIG. In this example, the perforated tube 13 for connecting the pile units 10 of the soil pile 1 is made of a flexible material as described above, so that it can be easily inserted into the guide tube 30. It is.
By the way, it is necessary to pull out the guide tube 30 after the soil pile 1 is arranged. However, after the pulling out, a gap is formed between the soil pile 1 and the hole wall 40.
Therefore, in this example, when the soil pile 1 is fed, a plurality of filling pipes 42 each having a jet nozzle 42n at the tip, which pumps a gap filling material 41 such as gap filling sand, are simultaneously introduced into the guide pipe 30. I try to send it in. At this time, when the filling pipe 42 is disposed on the frame 43 and the frame 43 is used as a support member of the pile unit 10, each pile unit 10 can be fed while being held at the center of the guide tube 30.
In this example, as shown in FIG. 3C, when the guide tube 30 is pulled out, the gap filler 41 is ejected from the ejection nozzle 42n of the filling pipe 42, and the soil pile 1 and the hole wall 40 are The gap filler 41 is filled in the gap between the two. At this time, if the length of the pile unit 10 is the same as the length of the steel pipe 31 constituting the guide pipe 30, the gap filler 41 is filled each time one steel pipe 31 is pulled out. The filler 41 can be uniformly filled around the pile unit 10. The filling pipe 42 may be returned to the ground side simultaneously with the steel pipe 31.
Thereby, as shown in FIG.3 (d), since the space | gap filler 41 is uniformly filled into the space | gap between the soil pile 1 and the drilling wall 40, ground subsidence can be prevented reliably.
In addition, when arranging multiple rows of soil piles 1, as shown in FIG. 2, for example, when one of the soil piles 1 adjacent in the depth direction extends in the east-west direction, It is desirable to arrange the pile units 10 evenly in the contaminated area K, for example, by arranging the other so as to extend in the north-south direction.

The nonwoven fabric 11 and the gap filler 41 between the buried filler 12 of the soil pile 1 and the contaminated soil in the contaminated area K are both materials in which the contaminant-decomposing microorganisms in the filler 12 can freely move. Therefore, since the microorganisms easily enter the contaminated area K and decompose the contaminants in the contaminated soil, the contaminated area K can be easily purified.
At this time, if air is supplied from the blower device 21 to the pollutant-decomposing microorganisms mixed in the filler 12 through the perforated tube 13, the microorganisms can be further activated. The purification of the region K can be further promoted.
Further, since the microorganisms diffuse into the contaminated area K, if necessary, the purified water is sent from the microorganism storage tank 22 to the soil pile 1 to replenish the pollutant-decomposing microorganisms. The purification of K can be further promoted.
The water blocking wall 24 constructed around the contaminated area K is a necessary facility for preventing the contaminated area K from spreading.

Thus, in this best mode, the non-woven bag having a donut-shaped cross section having a certain length in the soil (contaminated area) K containing the contaminant present in the ground immediately below the site where the building T is built. 11 is filled with a filler 12 such as sand or sawdust mixed with pollutant-decomposing microorganisms, and a pile unit 10 in which the filler is compacted is disposed in the hole of the nonwoven fabric bag 11, and a large number of through holes 13 h are provided. The soil pile 1 connected by using the perforated tube 13 is buried, and the contaminated soil in the contaminated area K is purified by the above-described microbial contaminant decomposing action, so that the contaminated area K is reliably and easily purified. be able to.
Moreover, since the pile unit 10 is compacted, it not only has sufficient strength, but when the soil pile 1 is embedded, a gap filling material 41 is filled in the gap between the soil pile 1 and the hole wall 40. Since it did in this way, the ground subsidence after the soil pile 1 construction can be prevented reliably.
Moreover, since the purified water containing air and pollutant-decomposing microorganisms can be sent through the perforated tube 13 so that the microorganisms can be activated and supplemented, the contaminated area K can be quickly purified. it can.

  In the above-described best mode, sand or sawdust is used as the filler 12 for mixing the pollutant-decomposing microorganisms. However, although it is expensive, the contaminated area K can be purified more quickly by using microorganism culture soil. can do.

  As described above, according to the present invention, a pile unit having a high strength in which a filler mixed with the above microorganisms is stored in a nonwoven fabric bag is manufactured, and these pile units are connected using a perforated tube. Since this is buried in the contaminated soil and the contaminated soil is purified by the action of decomposing the pollutants of the microorganisms in the filler, the contaminated soil can be purified efficiently and reliably. .

It is a figure which shows the structure of the soil pile which concerns on this best form. It is a figure which shows schematic structure of the purification system of the contaminated soil which concerns on this best form. It is a figure which shows the construction method of a soil pile. It is a figure which shows the purification method of the conventional contaminated soil.

Explanation of symbols

1 soil pile, 10 pile unit, 11 non-woven bag, 12 filler,
13 perforated tube, 13h through hole, 20 contaminated soil purification system, 21 blower, 22 microorganism storage tank, 23 supply pipe, 24 water blocking wall, 30 guide pipe,
31 steel pipe, 40 drilling wall, 41 void filler, 42 filling pipe,
42n jet nozzle, 43 frames, K contaminated area, T building.

Claims (5)

  While producing a pile unit containing a filler mixed with microorganisms that decompose contaminants in a non-woven bag of a predetermined length, these pile units are inserted into the filler of the pile unit, After connecting using a perforated tube having a large number of holes formed on its side surface, the connected pile unit is connected to the contaminated soil via a guide tube embedded in the soil containing the contaminant. After inserting into the existing area, pulling out the guide tube to construct a soil pile in the contaminated soil, and purifying the contaminated soil by the action of decomposing the microorganisms in the filler. To clean up contaminated soil.   2. The contaminated soil according to claim 1, wherein the nonwoven fabric bag is a nonwoven fabric bag having an annular cross section, and the pile units are connected to the holes of the nonwoven fabric bag through the perforated tube. Purification method.   The filling material is filled in a space between the soil pile and the excavation hole wall in which the guide pipe is embedded when the guide pipe is pulled out. To clean up contaminated soil.   4. The method for purifying contaminated soil according to claim 3, wherein the guide pipe is a guide pipe formed by connecting a plurality of steel pipes, and the length of the pile unit is the same as the length of the steel pipe. .   A soil pile having a filler mixed with microorganisms for decomposing the pollutant, which is constructed in a soil containing the pollutant, and comprising a plurality of non-woven bags of a predetermined length for storing the filler A soil pile comprising a main body and a perforated tube inserted into each of the cloth bags for connecting a plurality of non-woven bags.

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