JP4912932B2 - Purification system for contaminated soil - Google Patents

Description

  The present invention relates to a contaminated soil purification system in which a chemical solution for purification is injected into a contaminated soil layer in the ground.

  Conventionally, there is a known method for purifying contaminated soil by cutting a boring hole so that it crosses the contaminated soil layer in the ground by a curved boring method and spraying a cleaning chemical from a nozzle provided at the tip of the drilling tool. (For example, refer to Patent Document 1). This construction method is applied when the pollutant is an organochlorine compound, and the purification chemical for purifying the contaminated soil is water mixed with iron powder. Organochlorine compounds in the contaminated soil layer are reduced and decomposed by iron powder to make them harmless.

  A soil purification method is also known in which contaminants such as heavy oil are decomposed by microorganisms. In this case, a liquid containing a nutrient salt for activating microorganisms is injected into the contaminated soil layer as a chemical solution for purification. Here, in the purification method using microorganisms, it is necessary to continuously inject a chemical solution containing a nutrient salt into the contaminated soil layer for a long period of time. Conventionally, a vertical hole reaching the contaminated soil layer from the ground surface is drilled, and a chemical solution is injected into the contaminated soil layer through the vertical hole. However, this method cannot be used when facilities exist on the ground surface above the contaminated soil layer. Therefore, a chemical injection pipe is inserted into the borehole drilled so as to cross the contaminated soil layer, the chemical solution is supplied into this pipe, and the chemical solution is supplied to the contaminated soil layer from the injection holes formed in the axial direction of the pipe. It is desirable to keep injecting.

By the way, the contaminated soil layer is not homogeneous, and there are places where the chemical solution is difficult to enter and places where the contamination concentration is high. Therefore, if the chemical solution is simply injected into the contaminated soil layer from the chemical solution injection pipe inserted into the borehole, the chemical solution cannot be appropriately injected into each part of the contaminated soil layer.
JP 2000-135483 A

  In view of the above points, it is an object of the present invention to provide a contaminated soil purification system that can efficiently purify contaminated soil by appropriately injecting a chemical solution for purification into each part of the contaminated soil layer. Yes.

In order to solve the above-described problems, the present invention provides a purification system for contaminated soil in which a chemical solution for purification is injected into a contaminated soil layer in the ground, and the chemical solution is provided in a borehole drilled so as to cross the contaminated soil layer. An injection pipe is inserted, and the internal space of the chemical injection pipe is partitioned into a plurality of rooms by a plurality of partition members arranged at intervals in the pipe axis direction, and the chemical liquid is supplied to each room via a separate liquid supply hose. The chemical solution is supplied to the contaminated soil layer through a plurality of injection holes formed on the pipe wall on the outer periphery of each room, and the chemical solution for purification is supplied to each supply hose from each different supply source. It is characterized by being.

  According to the present invention, since the chemical liquid is supplied from each separate liquid supply source to each room in the chemical liquid injection pipe, the chemical liquid supply pressure and the type of the chemical liquid can be individually managed for each room. Therefore, even if there is a location where the chemical solution is difficult to enter in the contaminated soil layer, the chemical solution supply pressure to the corresponding room can be increased and the chemical solution can be reliably injected into the location. Further, it is possible to inject a high-performance chemical into a portion where the contamination concentration of the contaminated soil layer is high. Thus, since a chemical | medical solution can be appropriately inject | poured into each location of a contaminated soil layer according to the condition, contaminated soil can be purified efficiently.

  Further, in the present invention, each liquid supply source is constituted by each liquid tank installed on the ground surface, and the chemical liquid in each liquid tank is supplied to each room by gravity through each liquid supply hose. desirable. This is advantageous in reducing the running cost by injecting the chemical liquid over a long period of time, unlike the case where the chemical liquid is pumped to each liquid supply hose with a pump or the like, and does not consume power.

  In addition, in this case, the descending speed of the liquid level of the chemical solution in the liquid tank connected to the room located in the place where the chemical solution of the contaminated soil layer is easy to enter increases, and the chemical solution of the contaminated soil layer is difficult to enter. The descending speed of the liquid level of the chemical solution in the liquid tank connected to the located room becomes slow. Therefore, the situation of each part of the contaminated soil layer can be grasped based on the descending speed of the liquid level of the chemical solution in each liquid tank. And the chemical | medical solution can be appropriately inject | poured into each location of a contaminated soil layer by managing individually the supply pressure of the chemical | medical solution to each room by adjusting the liquid level of the chemical | medical solution in each liquid tank. That is, by increasing the liquid level of the liquid tank connected to the room located in the place where the chemical solution is difficult to enter and increasing the chemical solution supply pressure to this room, the chemical solution is also applied to the place where the chemical solution is difficult to enter. Can be injected reliably.

  Referring to FIG. 1, reference numeral 1 denotes a contaminated soil layer in the ground. In order to purify the contaminated soil layer 1 using microorganisms, a chemical solution injection pipe 2 is embedded so as to cross the contaminated soil layer 1, and a chemical solution containing microorganisms and nutrient salts for activating microorganisms is stored in the chemical solution injection pipe 2. To the contaminated soil layer 1.

  With reference to FIG. 2, the embedding construction method of the chemical injection pipe 2 will be described. First, as shown in FIG. 2A, the excavation tool 4 attached to the tip of the flexible casing pipe 3 finishes traversing the contaminated soil layer 1 from the ground located on one side of the contaminated soil layer 1. The boring hole 5 is drilled by the bending boring method. Here, the tip of the excavation tool 4 is formed on an inclined surface. When the excavation tool 4 is rotated through the casing pipe 3, the excavation is straight, but when the excavation tool 4 is not rotated, the excavation direction is bent by a radial reaction force component acting on the inclined surface at the tip of the excavation tool 4. Then, after drilling straight up to a predetermined depth obliquely downward from the ground surface, the drilling direction is bent and leveled, and the boring hole 5 is drilled so as to cross the contaminated soil layer 1.

  After drilling the boring hole 5, as shown in FIG. 2 (b), the chemical solution injection pipe 2 is inserted into the casing pipe 3 so that the tip thereof reaches the excavation tool 4. Next, the casing pipe 3 is pulled out from the boring hole 5. Here, if the excavation tool 4 is fixedly attached to the tip of the casing pipe 2, when the casing pipe 2 is pulled out, it is pushed by the excavation tool 4 that moves together with the casing pipe 2, and the chemical injection pipe 2 is removed from the boring hole 5. It will be pushed out. Therefore, in this embodiment, the excavation tool 4 is attached to the tip of the casing pipe 3 so as to be freely inserted and removed. Therefore, when the casing pipe 3 is pulled in the axial direction, the excavation tool 4 and the casing pipe 3 are separated, and the casing pipe 3 can be pulled out from the boring hole 5 while leaving the excavation tool 4 in the ground. As a result, the chemical injection pipe 2 stays in the borehole 5 as shown in FIG. 1 and is buried so as to cross the contaminated soil layer 1.

  In addition, you may provide the joint with the operation part which connects the excavation tool 4 to the casing pipe 3 removably. In this case, when the tip of the chemical injection pipe 2 reaches the excavation tool 4, the operation portion of the joint is pushed by the chemical injection pipe 2, and the connection between the excavation tool 4 and the casing pipe 3 by the joint is released. To do.

  Next, the chemical solution injection pipe 2 will be described. As shown in FIG. 3, the internal space of the chemical liquid injection pipe 2 is partitioned into a plurality of chambers 22 by a plurality of partition members 21 arranged at intervals in the pipe axis direction. The chemical solution is supplied individually through the control unit 23. And a chemical | medical solution is inject | poured into the contaminated soil layer 1 from the injection hole 24 formed in the pipe wall of the outer periphery of each room | chamber 22. FIG. The injection hole 24 is covered with a nonwoven fabric 25 wound around the outer peripheral surface of the pipe in order to prevent earth and sand from entering the injection hole 24.

  In addition, when the chemical solution injection pipe 2 is inserted into the boring hole 5 without the casing pipe 3, the chemical solution injection pipe 2 rubs the inner surface (natural ground) of the boring hole 5. Then, the earth and sand of the natural ground is pushed into the nonwoven fabric 25 and the nonwoven fabric 25 is clogged. Further, the nonwoven fabric 25 is peeled off and the earth and sand is pushed into the injection hole 24, and the injection hole 24 may be clogged. Thereby, poor injection of the chemical solution occurs. However, in the present embodiment, since the chemical liquid injection pipe 2 is inserted into the casing pipe 3 as described above, the chemical liquid injection pipe 2 does not rub the inner surface of the boring hole 5, and the above-described problems do not occur.

  Further, when the casing pipe 3 is pulled out from the boring hole 5, a gap is formed between the inner surface of the boring hole 5 and the outer peripheral surface of the chemical solution injection pipe 2. And if each room | chamber 22 of the chemical | medical solution injection pipe 2 connected via the space | gap on the outer side, the meaning which supplies a chemical | medical solution separately for every room 22 will be lost. Therefore, in the present embodiment, a plurality of gaps between the inner surface of the boring hole 5 and the outer peripheral surface of the chemical solution injection pipe 2 are divided into a plurality of regions in the pipe axis direction corresponding to the plurality of chambers 22 of the chemical solution injection pipe 2. The partition member 26 is attached to the outer peripheral surface of the chemical solution injection pipe 2. The partition member 26 is configured by laminating two annular plates made of an elastic material such as rubber, and the outer peripheral portion thereof is elastically pressed against the inner surface of the boring hole 5 to ensure the sealing performance between the regions. I am doing so. The partition member may be of a balloon type that expands and contracts, and after the casing pipe 3 is pulled out, the partition member may be expanded by supplying fluid such as air thereto.

  By the way, when the chemical solution injection pipe 2 is constituted by a single continuous pipe, the insertion distance of the partition member 21 from the end portion of the pipe becomes considerably long depending on the partition member 21. In order to insert the partition member 21 at such a long distance, the partition member 21 needs to be inserted into the chemical solution injection pipe 2 without receiving frictional resistance so much. As a result, the partition member 21 cannot be tightly fitted inside the chemical solution injection pipe 2, and it becomes difficult to ensure liquid tightness between the partition member 21 and the chemical solution injection pipe 2.

  Therefore, in the present embodiment, a plurality of short pipes 2a divided corresponding to the plurality of chambers 22 are connected to each other through joints 27 in a state in which each partition wall member 21 is fitted to the end of each short pipe 2a. The chemical solution injection pipe 2 is configured by being connected. According to this, since the partition member 21 is inserted at the end of the short pipe and the insertion distance becomes extremely short, there is no problem even if the insertion frictional resistance of the partition member 21 with respect to the short pipe 2a is large. Therefore, the partition member 21 can be tightly fitted in the short pipe 2a, and the liquid tightness between the short pipe 2a and the partition member 21 can be secured.

  Furthermore, the chemical solution injection pipe 2 has a certain degree of flexibility by connecting the plurality of short pipes 2a in a daisy chain to form the chemical solution injection pipe 2. Therefore, the chemical injection pipe 2 can be easily inserted even when the boring hole 5 has a bent portion. A cap 2b is attached to the tip of the leading short pipe 2a. Moreover, the two short pipes 2a 'on the tail end side in FIG. 1 are provided to push the short pipe 2a for injecting the chemical solution into the contaminated soil layer 1, and no chemical solution is supplied to the inside thereof.

  In the present embodiment, each partition member 21 is made of an elastic material such as rubber. Then, as shown in FIG. 4, each partition member 21 has a collection hole 21 a through which all the liquid supply hoses 23 corresponding to all the chambers 22 located in the pipe axial direction ahead of the partition member 21 are inserted. A split portion 21b that is located at one location around the hole 21a and that divides the partition wall member 21 in the circumferential direction is formed. According to this, the liquid supply pipe 23 can be accommodated in the collecting hole 21 a from the outside in the radial direction with the split portion 21 b opened, and the liquid supply hose 23 can be inserted into the partition wall member 21. Therefore, the liquid supply hose 23 can be inserted through the partition wall member 21 in the vicinity of the short pipe 2a, and the partition wall member 21 can be fitted into the end of the short pipe 2a. Therefore, it is not necessary to slide the partition member 21 with respect to the liquid supply hose 23 from the terminal for a long distance, and the assembling work is facilitated.

  The gap between the liquid supply hoses 23 in the collecting hole 21a is closed with a caulking agent 21c. In addition, the partition wall member 21 fitted in the leading short pipe 2a has a small number of liquid supply hoses 23 inserted therethrough and a short distance from the tip of the liquid supply hose 23. You may form the hole penetrated separately.

  After the chemical liquid injection pipe 2 is buried, the chemical liquid is supplied to the respective liquid supply hoses 23 from the different liquid supply sources. In this embodiment, each liquid supply source is composed of each liquid tank 6 installed on the ground surface as shown in FIG. Each liquid supply hose 23 is connected to a valve 6 a provided at the bottom of each liquid tank 6. Thereby, the chemical | medical solution in each liquid tank 6 is supplied to each room | chamber 22 of the chemical | medical solution injection | pouring pipe 2 via each liquid supply hose 23 by gravity.

  By the way, it is also possible to pump the chemical liquid to each liquid supply hose 23 by each pump as a liquid supply source. However, this consumes electric power, and the running cost increases when the chemical solution is continuously injected over a long period of time, such as half a year. On the other hand, this embodiment is advantageous in reducing running cost without consuming electric power.

  The injection of the chemical liquid is started in a state where the liquid levels of the chemical liquids in all the liquid tanks 6 are aligned at a predetermined level. Here, the contaminated soil layer 1 is not homogeneous, and a place where a chemical solution is easy to enter and a place where it is difficult to enter are mixed. A room located in a place where the chemical solution in the contaminated soil layer 1 is difficult to enter because the descending speed of the liquid level of the chemical solution in the liquid tank 6 connected to the room 22 located in the place where the chemical solution in the contaminated soil layer 1 is easy to enter is increased. The descending speed of the liquid level of the chemical solution in the liquid tank 6 connected to 22 is slow. Therefore, the situation of each location of the contaminated soil layer 1 can be grasped based on the descending speed of the liquid level of the chemical solution in each liquid tank 6.

  After grasping the situation of each part of the contaminated soil layer 1 in this way, the supply pressure of the chemical liquid to each room 22 is individually managed by adjusting the liquid level of the chemical liquid in each liquid tank 6. Thereby, a chemical | medical solution can be appropriately inject | poured into each location of the contaminated soil layer 1. FIG. That is, by making the liquid level of the liquid tank 6 connected to the room 22 located in the place where the chemical solution is difficult to enter relatively high and increasing the chemical solution supply pressure to the room 22, the chemical solution is difficult to enter. Can reliably inject the drug solution.

  Moreover, it is also possible to inject | pour a high performance chemical | medical solution into the location where the contamination density | concentration of the contaminated soil layer 1 is high there. Thus, the contaminated soil can be efficiently purified by individually managing the supply pressure of the chemical solution and the type of the chemical solution according to the situation of each location of the contaminated soil layer 1.

  In addition, adjustment of the liquid level of the chemical solution in each liquid tank 6 may be performed manually or automatically using a float valve or the like.

Explanatory drawing which shows the soil purification system of embodiment of this invention. Explanatory drawing which shows the embedding construction method of the chemical | medical solution injection pipe used with the soil purification system of embodiment. The longitudinal cross-sectional view of the principal part of the chemical injection pipe of the chemical injection pipe used with the soil purification system of embodiment. The cross-sectional view of the partition member arrange | positioned in the chemical | medical solution injection pipe of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Contaminated soil layer, 2 ... Chemical solution injection pipe, 21 ... Partition member, 22 ... Room, 23 ... Liquid supply hose, 24 ... Injection hole, 5 ... Boring hole, 6 ... Liquid tank.

Claims (3)

A contaminated soil purification system in which a chemical solution for purification is injected into a contaminated soil layer in the ground,
A chemical injection pipe is inserted into the borehole drilled to cross the contaminated soil layer,
The internal space of the chemical liquid injection pipe is partitioned into a plurality of rooms by a plurality of partition members arranged at intervals in the pipe axis direction, and the chemical liquid is supplied to each room via a separate liquid supply hose. The chemical solution is injected into the contaminated soil layer from a plurality of injection holes formed on the outer pipe wall of the
A contaminated soil purification system, wherein a chemical solution for purification is supplied to each liquid supply hose from a separate liquid supply source.   2. Each liquid supply source is constituted by each liquid tank installed on the ground surface, and a chemical solution in each liquid tank is supplied to each room by gravity through the respective liquid supply hoses. Contamination soil purification system.   The system for purifying contaminated soil according to claim 2, wherein the supply pressure of the chemical liquid to each room is individually managed by adjusting the liquid level of the chemical liquid in each liquid tank.

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