JP2011177603A - Electrode well constituting pipe and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an electrode well constituting pipe which can be easily formed to have the length corresponding to the depth of the soil to be cleaned, is excellent in construction property and is used for in-situ cleaning. <P>SOLUTION: A porous synthetic resin pipe 22 is forcibly inserted into a hard synthetic resin pipe 21 having a plurality of through-holes 21a formed on the peripheral surface thereof. The outer peripheral surface of the porous synthetic resin pipe 22 is adhered/joined to the inner peripheral surface of the hard synthetic resin pipe 21 to integrate both pipes into one body so that the electrode well constituting pipe 2 is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pipe material constituting an electrode well installed on the ground in a method for purifying contaminated soil in situ.

  As countermeasures when soil contamination by heavy metals or organic compounds is discovered, methods such as excavating the ground containing contaminated soil and taking it out of the field, solidifying it with a solidifying agent to insolubilize it in situ, and preventing contamination from spreading There are known methods of driving steel plates into the ground and confining them in place, but large-scale construction is required to excavate the ground and drive steel plates. It does not remove the pollution itself, and even if it is taken out of the field, the contaminated soil remains and is not a fundamental solution to purify the soil.

  Therefore, as a method of fundamentally removing soil contamination and purifying it in situ, as shown in FIG. 3, an electrode called an electrode well is buried in the ground containing the contaminated soil, By adjusting the pH of the soil by flowing a direct current through the electrolyte injected into the soil, it ionizes the contaminants with the charge contained in the ground, and collects the contaminant ions dissolved in the electrolyte. In-situ purification technology (electric remediation method) for contaminated soil is being put into practical use.

  Electrode wells buried in the ground by this in-situ purification technology have an electrode placed inside a cylindrical tube with water permeability, take in pollutant ions in the soil moving toward the electrode into the cylindrical tube, It is constructed so that it can be dissolved in and recovered from the tube opening, and the cylindrical tube has a synthetic resin tube provided with a large number of holes in its peripheral surface, a ceramic tube having a porous tube wall, The thing formed in the mesh shape, the structure which covered the inner peripheral surface of the said synthetic resin pipe | tube with the semipermeable membrane, etc. are utilized (for example, refer patent documents 1-4).

JP 7-48827 A JP 2006-346519 A JP 2006-346567 A JP 2005-279399 A

When a synthetic resin tube with a large number of through holes is used as the cylindrical tube of the electrode well, the electrolyte injected into the cylindrical tube is likely to leak into the ground from the through hole, so that the charged liquid is always replenished into the cylindrical tube. In addition, the soil and dust components enter the cylindrical tube together with the contaminant ions and dissolve in the electrolyte, and when collecting the contaminants, the contaminant ions in the electrolyte and others A separate process step is required.
If a tube with a porous or meshed tube wall is used as the cylindrical tube, it is possible to collect only contaminant ions through the tube wall with little leakage of the electrolyte solution. Molding is difficult and the molding cost must be high. It is necessary to bury the electrode well at a depth corresponding to the depth of the soil to be purified, but it is difficult to form a long length of several meters with the above-mentioned pipe material. Since it cannot be constructed, the purifiable depth is limited. Porous pipes and mesh pipes are vulnerable to intensive loads, their ends are easily chipped and cracked, and may be crushed by earth pressure. Careful handling is required, and there is a problem that workability is poor.
The structure with the inner peripheral surface of the synthetic resin tube covered with a semipermeable membrane is better in workability than a porous tube, etc., but is difficult to mold and expensive, and the semipermeable membrane is easy to peel off. There is also a problem in terms of durability and lacks practicality.

  In view of such a problem of the prior art, the present invention can be recovered by allowing only contaminant ions to permeate from the soil without leaking the electrolyte, and according to the depth of the soil to be purified. It is an object of the present invention to obtain an electrode well constituent tube that can be easily configured to have a long length and is excellent in workability.

  The present invention for solving the above-mentioned problems is a porous synthetic resin tube on the inner peripheral surface of a hard synthetic resin tube in which a plurality of through holes are formed on the peripheral surface in an electrode well constituting tube used for in-situ purification of contaminated soil. It is characterized in that the outer peripheral surfaces of the two are joined and brought into close contact with each other.

In the above configuration, the rigid synthetic resin pipe is preferably a cylindrical pipe made of polyvinyl chloride or other resin material formed in accordance with JIS standards.
By using pipes of JIS standard products, electrode wells can be constructed at low cost using accessories such as general-purpose joints and caps, and the lengths of pipes can be adjusted by connecting the pipes with the joints. Processing can be performed easily and flexibly at the construction site according to the soil to be purified.
The plurality of through holes formed in the peripheral surface of the hard synthetic resin tube can efficiently take in the contaminant ions directed to the electrode into the tube and do not cause a decrease in the rigidity of the tube material. An appropriate number can be formed in an appropriate shape at an appropriate position.

A porous synthetic resin tube is a porous cylindrical tube whose tube wall is formed in a pore diameter that minimizes water permeation and allows ion permeation, and is a sintered molded product made of ultrahigh molecular weight polyethylene, such as this It is preferable to use a porous plastic molded product “Fildas” (registered trademark) which is the product of the applicant.
If the pore size is as described above, the electrolyte injected into the tube will not leak to the outside. On the other hand, contaminant ions in the soil can be taken into the tube through the tube wall and dissolved in the electrolyte. . Moreover, the porous synthetic resin tube can change the hole diameter of a tube wall by setting a raw material and molding conditions suitably, and can set the transmittance | permeability which is filtration performance suitably.

  The electrode well structure pipe having the above-described structure is composed of a hard synthetic resin pipe having a through hole formed in the peripheral surface and a porous synthetic resin pipe having an outer diameter that can be compactly fitted inside the hard synthetic resin pipe. Prepare and insert the porous synthetic resin tube into one end of the hard synthetic resin tube with the tube axes aligned and press-fitted into the inner surface of the hard synthetic resin tube. It can be manufactured by joining the outer peripheral surfaces of the tubes and bringing them into close contact with each other.

Such an electrode well constituting tube is inserted with the bottom closed by the bottom lid in a pothole formed by excavating the soil to be purified, with the bottom end covered with a bottom lid and closed. Then, a rod-like electrode is installed in the buried tube to constitute an electrode well.
Electrode wells are arranged in parallel on the ground of the soil to be cleaned, with a pair of positive and negative electrodes spaced apart from each other at appropriate intervals.Each electrode is connected to the control device of the purification treatment plant with an electric cable and connected to the pipe port. Is connected to an electrolyte treatment tank for pouring and collecting the electrolyte.

According to the electrode well constituting pipe of the present invention, a porous synthetic resin pipe is press-fitted into a hard synthetic resin pipe having a through-hole formed in the peripheral surface, and the peripheral surfaces of the inner and outer pipes are tightly joined. Therefore, the electrolytic solution is stored inside the porous synthetic resin tube and does not leak to the outside. On the other hand, the contaminant ions in the soil pass through the through hole of the hard synthetic resin tube, and the tube of the porous synthetic resin tube. It is possible to penetrate the wall and enter the constituent tube, dissolve in the stored electrolyte, and be reliably recovered together with the electrolyte.
Since the entire porous synthetic resin pipe is covered with the hard synthetic resin pipe and held in the pipe, it is subject to impact and pressure during handling such as transferring to the construction site or burying it. However, it does not cause any damage such as deformation or cracking, and can be handled in the same way as handling a hard synthetic resin tube alone, so that the construction of the electrode well becomes simple.
In addition, since pipes of JIS standard products are used, electrode wells can be processed easily and flexibly at the construction site, such as adjusting the length by connecting the electrode well constituent tubes using general-purpose joints. It becomes possible.

It is the schematic block diagram which fractured | ruptured and showed the electrode well comprised using the electrode well structure pipe | tube of this invention. It is an external view of the hard synthetic resin pipe | tube and porous synthetic resin pipe | tube which comprise the electrode well structure pipe | tube of FIG. It is a figure for demonstrating the structure of the soil in-situ purification process technique.

A preferred embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an electrode well constructed by using an electrode well constituting tube according to an embodiment of the present invention. In the figure, reference numeral 1 is an electrode well, 2 is an electrode well constituting tube, 3 is an electrode, Each bottom lid is shown.

  As shown in the drawing, the electrode well constituting pipe 2 has a porous synthetic resin pipe 22 coaxially arranged inside a hard synthetic resin pipe 21 having a large number of through holes 21a formed on the peripheral surface thereof, and the hard synthetic resin pipe 21 is arranged. The outer peripheral surface of the porous synthetic resin tube 22 is tightly joined and integrated with the inner peripheral surface.

  Specifically, the hard synthetic resin tube 21 is a cylindrical tube having an appropriate thickness, and a plurality of rows of circular through holes 21a are provided at predetermined intervals along the circumferential direction and the longitudinal direction over the entire circumferential surface. Formed. The porous synthetic resin tube 22 is a cylindrical tube having an outer diameter that can be tightly fitted inside the hard synthetic resin tube 21, and its outer peripheral surface is the entire inner peripheral surface of the hard synthetic resin tube 21. It is tightly bonded over and is integrally installed inside the hard synthetic resin tube 21.

  As shown in FIG. 2, the electrode well constituting tube 2 configured as described above is a state in which the tube axis O of the hard synthetic resin tube 21 and the porous synthetic resin tube 22 aligned with the through hole 21 a on the peripheral surface is aligned. Thus, the porous synthetic resin tube 22 can be pushed into the inside from one end of the hard synthetic resin tube 21 and press-fitted, and the inner and outer peripheral surfaces of both tubes can be tightly joined and integrated. A plurality of short porous synthetic resin tubes 22 may be press-fitted into the long hard synthetic resin tube 21 and the inner and outer peripheral surfaces may be tightly bonded.

Further, the use of a JIS standard resin pipe as the hard synthetic resin pipe 21 has the following effects.
In this case, for example, a JIS standard hard synthetic resin tube 2 having a nominal diameter (inner diameter) of 125 mm and a length of 1000 mm is used, and a circular or slit-shaped through-hole is previously provided on the peripheral surface so that the porosity is at least 10% or more. 21a is formed, and on the other hand, a porous synthetic resin tube 22 having an outer diameter of 125 mm and a length of 1000 mm is prepared, and this is press-fitted into the inside from one end of the hard synthetic resin tube 21, and the inner and outer peripheral surfaces of both tubes are formed. The composite pipe which comprises the electrode well structure pipe | tube 2 is completed by tightly bonding and integrating.
If this composite tube is used as one unit and a plurality of units are connected by a JIS standard socket or the like, it is possible to form the electrode well constituting tube 2 whose length is set in units of 1 m. Various standard products can be easily used, such as attaching and closing a JIS standard cap (bottom lid 4) at the bottom of the electrode well constituting tube 2.
In addition, other than the target portion to be repaired in the electrical restoration method, for example, a piping route from the ground surface to the pump can be configured by simply and flexibly piping using a general-purpose resin pipe of JIS standard, for example, branching. The piping path can also be configured freely.

  In addition, the through-hole 21a formed in the surrounding surface of the hard synthetic resin pipe | tube 21 is not limited to the shape shown in figure, It can be set as appropriate shapes, such as what was opened in the shape of a long slit or a strip | belt shape. Moreover, the position and number which form the through-hole 21a can also be set suitably.

1 Electrode Well, 2 Electrode Well Constituent Tube, 21 Hard Synthetic Resin Tube, 22 Porous Synthetic Resin Tube, 3 Electrode, 4 Bottom Cover, O Tube Shaft

Claims (2)

In the electrode well construction pipe used for in-situ purification of contaminated soil,
An electrode well constituting tube characterized in that the outer peripheral surface of a porous synthetic resin tube is joined and integrated with the inner peripheral surface of a hard synthetic resin tube having a plurality of through holes formed in the peripheral surface. In the manufacturing method of the electrode well constituent pipe used for in-situ purification of contaminated soil,
A porous synthetic resin tube is press-fitted into a hard synthetic resin tube having a plurality of through holes formed in the peripheral surface, and the outer peripheral surface of the porous synthetic resin tube is joined to the inner peripheral surface of the hard synthetic resin tube. A method for producing an electrode well-structured tube, wherein the tubes are integrated.

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