Insert tool and well management method

Abstract

To provide an insertion tool and a well management method capable of reducing the amount of purging performed before sampling groundwater.SOLUTION: An insertion tool 2 inserted inside a water quality observation well 9 for monitoring groundwater 10 has a structure that prevents the penetration of the groundwater 10 into the insertion tool 2. A lower end portion thereof does not touch a bottom of the water quality observation well 9 when installed in the water quality observation well 9. The insertion tool 2 may have, for example, a structure in which a rod body or a hollow tubular portion 4 is closed. The insertion tool 2 is in a state of floating on the groundwater 10, for example, and an upper end portion of the insertion tool 2 is in contact with a lid portion 8 of the water quality observation well 9 to restrict upward movement due to buoyancy.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inserter and a well management method.

Background Art

[0002] In order to monitor the situation of groundwater contaminated with harmful substances, water quality observation wells are installed. The water quality observation well has a screen (opening) on the pipe wall and can collect groundwater inside the pipe. The construction method of the water quality observation well is described in, for example, Patent Documents 1 and 2, and a method of collecting a sample from the groundwater accumulated in the water quality observation well to confirm the contamination situation is common.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The groundwater sampling method is detailed in "Appendix-7. Groundwater Sample Collection Method" of the "Guidelines on Investigations and Measures Based on the Soil Pollution Countermeasures Law (https: / / www.env.go.jp / water / dojo / gl_ex-me / index.html)". This guideline states that when collecting groundwater samples, the groundwater samples should be collected after performing "purging before sampling". The pumping volume for purging is described as "using 3 to 5 times the amount of stagnant water in the well as a reference". For example, in the case of the most common "VP50" PVC pipe (inner diameter 51 mm), if the stagnant depth of groundwater is "10 m", the purging volume per water quality observation well is "60 L to 100 L". Since the surplus water after purging needs to be properly treated, basically it is treated at the on-site water treatment facility, etc. However, in places where such equipment is not available, it is necessary to move the collected contaminated groundwater to a place where it can be treated, which is time-consuming and costly. Therefore, it is desirable to minimize the purging volume as much as possible. From such a perspective, the present invention provides an insert and a well management method capable of reducing the purging volume performed before collecting groundwater.

Means for Solving the Problem

[0005] The insert according to the present invention is an insert inserted into the interior of a water quality observation well for monitoring groundwater. This insert has a structure that does not allow the groundwater to penetrate, and in a state where it is installed in the water quality observation well floating on the groundwater, The lower end does not contact the bottom of the water quality observation well. the upper end of the insert tool contacts the lid of the water quality observation well, thereby restricting upward movement due to buoyancy. The insert may have a structure in which a rod body or a hollow tubular portion is closed. By inserting the insert according to the present invention into the water quality observation well, the purging volume performed before collecting groundwater can be reduced. As a result, the labor and cost for treating the surplus water after purging can be reduced. Also, since the lower end of the insert does not contact the bottom of the water quality observation well, it becomes difficult to stir up the mud accumulated at the bottom of the water quality observation well when pulling out the insert, and it does not affect the collection of groundwater. Also, the insert tool can be kept in an appropriate position. In addition, the well management method according to the present invention is a method for managing a water quality observation well for monitoring groundwater. This well management method includes a well installation step of installing the water quality observation well and an inner insert installation step of installing an inner insert in the water quality observation well. This inner insert has a structure that prevents the groundwater from entering, and when installed in the water quality observation well floating on the groundwater, the lower end does not contact the bottom of the water quality observation well. the upper end of the insert tool contacts the lid of the water quality observation well, thereby restricting upward movement due to buoyancy. In the well management method according to the present invention, the purge volume performed before groundwater extraction can be reduced. As a result, the labor and cost of treating the surplus water after purging can be reduced. In addition, when pulling out the inner insert, it becomes difficult to stir up the mud accumulated at the bottom of the water quality observation well, so it does not affect the groundwater extraction. Also, the insert tool can be kept in an appropriate position.

Effect of the Invention

[0006] According to the present invention, the purge volume performed before groundwater extraction can be reduced.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments for carrying out the present invention will be described in detail with appropriate reference to the drawings. Each drawing only schematically shows the present invention to such an extent that it can be sufficiently understood. Therefore, the present invention is not limited only to the illustrated examples. In each drawing, common components and similar components are denoted by the same reference numerals, and redundant descriptions thereof are omitted. <Regarding the insert tool according to the embodiment> With reference to FIG. 1, the configuration of the insert tool 2 according to the embodiment will be described. FIG. 1 is a diagram for explaining the insert tool according to the embodiment of the present invention. (a) is a cross-sectional view of the water quality observation well, (b) is a cross-sectional view in a state where the insert tool is inserted into the water quality observation well, (c) is a plan view in a state where the lid is attached to the water quality observation well, and (d) is a plan view in a state where the insert tool is inserted into the water quality observation well (with the lid removed). The insert tool 2 shown in FIG. 1(b) is a tool to be inserted into the water quality observation well 9. As shown in FIG. 1(a), the water quality observation well 9 is for checking the purification status of the aquifer and enables monitoring of the groundwater 10 by collecting the groundwater 10 inside. The structure of the water quality observation well 9 is not limited. For example, it may be a tubular member (well pipe) with a screen (opening) formed and embedded in a boring hole. At the bottom of the water quality observation well 9, for example, a sedimentation part 9a is provided, and sediment 9b is deposited.

[0009] As shown in FIG. 1(b), the insert tool 2 includes a hollow tubular part 4 and a closing part 5 that closes the tubular part 4 so that the groundwater 10 does not enter the inside of the tubular part 4. In the present embodiment, the closing part 5 closes one end of the tubular part 4 (the side facing the bottom of the water quality observation well 9 when the insert tool 2 is arranged in the water quality observation well 9). The side facing the bottom of the water quality observation well 9 when the insert tool 2 is arranged in the water quality observation well 9 is referred to as the "lower end", and the opposite side of the lower end (the side corresponding to the ground) is referred to as the "upper end". The closing part 5 is, for example, a cap or the like that fits the size of the tubular part 4, and is closed by being attached to the tubular part 4 so that the groundwater 10 does not enter the tubular part 4. Note that the closing part 5 may be integrated with the tubular part 4, and the shape is not particularly limited. The closing part 5 may have, for example, a rounded shape or a shape with a tapered tip. By adopting such a structure that closes the tubular part 4, groundwater does not enter the insert tool 2, and the amount of groundwater 10 corresponding to the volume of the insert tool 2 can be reduced. Note that the position of the closing part 5 is not limited to the lower end part of the tubular part 4. The tubular part 4 is cylindrical as shown in Fig. 1(d) (assuming a cylinder in this embodiment), and has a length approximately the same as the depth of the water quality observation well 9 (the length of the well pipe). Note that the inserter 2 may be a rod without a hollow interior. The materials of the tubular part 4 and the closing part 5 are preferably materials that can be used as well pipes (for example, made of vinyl chloride, polyvinyl chloride (PVC), and stainless steel (SUS)). Regarding the materials that can be used as well pipes, there is a description in, for example, "Soil Pollution Countermeasures Law Guidelines, Part 1: Guidelines on Investigations and Measures Based on the Soil Pollution Countermeasures Law (Revised 3rd Edition), Appendix (Appendix - 7. Groundwater Sampling Method)".

[0010] The material of the tubular part 4 is preferably a material that floats on the groundwater 10. Materials such as vinyl chloride and polyvinyl chloride, which generate buoyancy when the inserter 2 is inserted into the water quality observation well 9, are suitable. That is, in the state where the inserter 2 is inserted into the water quality observation well 9, it is preferable that the lower end of the inserter 2 does not contact the bottom of the water quality observation well 9. The reason for not contacting the bottom of the water quality observation well 9 with the inserter 2 is to prevent stirring up mud when pulling out the inserter 2. If mud is stirred up, it will affect the subsequent groundwater 10 sampling. However, if the configuration is such that the inserter 2 does not contact the bottom of the water quality observation well 9, it becomes difficult to stir up the mud accumulated at the bottom. For example, the length of the tubular part 4 is adjusted so that "the length of the tubular part 4 = the total length of the well pipe - the height of the mud accumulation part 9a", and in the aquifer 11, the inserter 2 is always in a state of receiving buoyancy so that the tubular part 4 does not reach the bottom of the water quality observation well 9. In this embodiment, by closing the lower end of the tubular part 4 with the closing part 5, the maximum buoyancy can be obtained. Also, in order to prevent the lower end of the inserter 2 from contacting the bottom of the water quality observation well 9, the inserter 2 may be suspended from above by a suspension means (not shown) or the inserter 2 may be fixed to the water quality observation well 9 by a fixing means (not shown).

[0011] As shown in Fig. 1(d), the outer diameter of the tubular portion 4 is smaller than the inner diameter of the water quality observation well 9 (the inner diameter of the well pipe), and it can be inserted into the water quality observation well 9. By making the space between the tubular portion 4 and the water quality observation well 9 as small as possible, the purging amount can be reduced. Fig. 2 shows the specifications of a vinyl chloride pipe (which may be abbreviated as a "PVC pipe" in some cases). For example, when using a PVC pipe of "VP50" as the well pipe, using a PVC pipe of "VP40" as the tubular portion 4 is preferable because the space between the tubular portion 4 and the water quality observation well 9 can be minimized. However, in this case, there is only a margin of 3 mm, so if the well length of the water quality observation well 9 increases, there is a risk that the insertion and removal of the internal insert 2 cannot be smoothly performed within the water quality observation well 9. In such a case, depending on the length of the water quality observation well 9, instead of "VP40", it is better to use a PVC pipe of "VP30" for the tubular portion 4, although the purging amount will be larger, but the insertion and removal of the tubular portion 4 are easier. The tubular portion 4 may be composed of a single long tubular member (e.g., a PVC pipe), or may be composed of a plurality of tubular members connected together. For example, when the water quality observation well 9 is deep and the axial dimension of the tubular portion 4 becomes long, it is necessary to connect a plurality of tubular members. It is advisable to perform adhesion or the like at the connection portion of the tubular members so that groundwater 10 does not infiltrate as in the lower end portion. In this case, a socket may be used, or a straight pipe with an adhesive receiving port may be used. Also, the both ends of the tubular members may be threaded and the individual tubular members may be connected by screw joints. When the both ends of the tubular members are threaded, the connection can be released as needed. Therefore, for example, when there is an obstacle to the insertion or extraction of the internal insert 2, it is possible to perform the operation with the connection released. In addition, a device may be provided so that the internal insert 2 does not float too much due to buoyancy. For example, after inserting the internal insert 2, a lid portion 8 (see Fig. 1(b)) is provided at the pipe head portion of the well pipe (the entrance of the water quality observation well 9) so that the upper end portion of the internal insert 2 does not protrude above the entrance of the water quality observation well 9. By doing so, the movement of the internal insert 2 that attempts to move upward due to buoyancy is restricted by the presence of the lid portion 8, and the internal insert 2 is kept in an appropriate position.

[0012] <Regarding the well management method using the internal insert according to the embodiment> Referring to FIG. 1, a well management method using the inserter 2 according to the embodiment will be described. First, a water quality observation well 9 is installed in the ground (well installation step). Next, an inserter 2 is manufactured by connecting a tubular member (for example, a PVC pipe) in accordance with the depth of the water quality observation well 9, and the manufactured inserter 2 is inserted into the water quality observation well 9 and installed (inserter installation step). Since the material of the inserter 2 is a material that floats on the groundwater 10, the inserter 2 inserted into the water quality observation well 9 floats without contacting the bottom of the water quality observation well 9. When removing the inserter 2 from the water quality observation well 9, it may be removed sequentially while disassembling the tubular member (releasing the connection of the tubular member). When collecting the groundwater 10, it is good because the work is easy when the inserter 2 is removed from the water quality observation well 9. Note that it is also possible to collect water with the inserter 2 installed. For example, if a difference is provided between the inner diameter of the water quality observation well 9 and the outer diameter of the inserter 2, a tube or the like can be inserted into the gap between the water quality observation well 9 and the inserter 2, and groundwater can be collected using a pump or the like.

[0013] When assuming the water quality observation well 9 shown in FIG. 1(a), for example, before collecting groundwater, purging (discharging contaminated groundwater) about three times the amount of water in the region marked with the symbol V is required. The water volume V is "V = (π(D / 2) 2 )×H". Here, "D" is the inner diameter of the water quality observation well 9, and "H" is the depth dimension of the aquifer 11. On the other hand, as shown in FIG. 1(b), assume purging when the inserter 2 is inserted into the water quality observation well 9. In this case, due to the presence of the inserter 2, the water volume in the space serving as the purging reference is reduced by "(π(d / 2) 2 )×H". Here, "d" is the outer diameter of the inserter 2, and "H" is the depth dimension of the aquifer 11. As a result, the amount of water finally requiring purging also decreases. As described above, by inserting the inserter 2 into the water quality observation well 9, the amount of purging performed before collecting groundwater can be reduced. As a result, the labor and cost of treating the surplus water after purging can be reduced. Further, since the lower end portion of the inserter 2 does not contact the bottom of the water quality observation well 9, it becomes difficult to stir up the mud accumulated at the bottom of the water quality observation well 9 when pulling out the inserter 2, and it does not affect the collection of the groundwater 10. Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented without changing the gist of the claims.

[0014] 2 Insert 4 Tubular part 5 Closing part 8 Cover part 9 Water quality observation well 10 Groundwater 11 Aquifer

Claims

1. An insert to be inserted inside a water quality observation well for monitoring groundwater, which has a structure that prevents the groundwater from entering the insert, floats in the groundwater when installed in the water quality observation well, and its lower end does not contact the bottom of the water quality observation well, wherein upward movement due to buoyancy is restricted by the upper end of the insert contacting the lid of the water quality observation well. An insert characterized by the above.

2. The insert has a structure in which a rod body or a hollow tubular part is closed. The insert according to claim 1, characterized by the above.

3. A well management method for a water quality observation well for monitoring groundwater, comprising a well installation step of installing the water quality observation well, and an insert installation step of installing an insert inside the water quality observation well, wherein the insert has a structure that prevents the groundwater from entering, floats in the groundwater when installed in the water quality observation well, its lower end does not contact the bottom of the water quality observation well, and upward movement due to buoyancy is restricted by the upper end of the insert contacting the lid of the water quality observation well. A well management method characterized by the above. ​

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