JP2005015935A - Method for sealing polluted soil, and bag for sealing polluted soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bag which can suitably be used for sealing highly water-containing polluted soil accumulated in rivers, lakes, marshes or the like and can efficiently filter the polluted soil up to a level not needing a drain treatment, and to provide a method for sealing the polluted soil with the bag. <P>SOLUTION: This bag for sealing the polluted soil containing injurious substances is characterized by forming the bag from a woven fabric which comprises synthetic fiber multi-filament yarns, has a cover factor of ≥1,900, an air permeability of ≤10 cc/cm<SP>2</SP>/sec and a wet elongation of ≤15 %. The polluted soil containing the injurious substances is put in the water-permeable bag, and then dehydrated to remove water contained in the polluted soil from the bag and simultaneously leave the injurious substances adhered to the polluted soil in the bag. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is capable of dehydrating and decontaminating soil contaminated with dioxins, PCBs, etc. deposited in, for example, rivers and lakes, and at the same time, can be suitably used for containment of contaminated soil, and can be contained inside the bag It relates to a method for containing contaminated soil.
[0002]
[Prior art]
Conventionally, a method for filling and containing contaminated soil in a bag made of woven fabric or non-woven fabric has been proposed. For example, in order to prevent expansion destruction due to press-fitting of contaminated soil, a water-permeable bag made of chemical fiber reinforced with a reinforcing material The use of a body is disclosed (Patent Document 1).
However, in the above method, there is no description about the properties required for the woven or knitted fabric and the nonwoven fabric in order to efficiently fill and contain the contaminated soil having a high water content, and as exemplified in the examples. In addition, when soil contaminated with high-concentration dioxins is filtered, it is difficult to reduce the dioxin concentration in the wastewater, which requires further wastewater treatment.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-178000
[Problems to be solved by the invention]
The present invention eliminates the above-mentioned problems of the prior art, and efficiently contaminates soil with a high water content accumulated in rivers, lakes, etc., and is capable of filtering contaminated soil to a level that does not require wastewater treatment. It is an object of the present invention to provide a bag body that can be suitably used for containment and a method for containing contaminated soil using the bag body.
[0005]
[Means for Solving the Problems]
The inventors of the present invention have found that the above object can be achieved when a bag is formed of a woven fabric in which the cover factor, the air permeability, and the wet elongation are controlled in specific ranges, and have reached the present invention.
That is, the present invention is a bag for containing contaminated soil containing harmful substances, the bag comprising a multifilament yarn of synthetic fibers, and a cover factor calculated by the following formula (1): A fabric in which (CF) is 1,900 or more, air permeability is 10 cc / cm ² / sec or less, and the wet elongation of the fabric under the tension (Y) calculated by the following formula (2) is 15% or less. It is related with the bag body for containment of the contaminated soil characterized by being formed from.
Cover factor (CF) = {fineness of warp constituting woven fabric (dtex) × 0.9} ^1/2 × {warp density of woven fabric (lines / inch)} + {fineness of weft constituting woven fabric (dtex) × 0.9} ^1/2 × {weft density of fabric (lines / inch)} ……… (1)
Tension (Y) = 1.64X ² + 1.11X [N / cm] (2)
[In Formula (2), X represents the perimeter (m) of a bag. ]
Here, the multifilament yarn of the synthetic fiber is preferably a multifilament yarn made of at least one synthetic fiber selected from the group consisting of polyester, nylon, vinylon, and polypropylene.
The multifilament yarn of synthetic fiber is particularly preferably a multifilament yarn made of polylactic acid fiber.
Next, according to the present invention, after contaminated soil containing harmful substances is placed in a water-permeable bag, moisture contained in the contaminated soil in the bag is permeated to the outside of the bag to dehydrate, and adheres to the contaminated soil. The present invention relates to a method for containing contaminated soil, characterized by using the above-mentioned bag for containing contaminated soil as the bag when the harmful substance is left in the bag and contained in the bag.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the multifilament yarn of synthetic fiber used in the present invention include multifilament yarns such as polyester, nylon, vinylon, and polypropylene. Among them, polyester multifilament yarn is preferable. In particular, among polyester multifilaments, when a polyethylene terephthalate multifilament yarn having good physical properties or a bag body is to be permanently embedded, a multifilament made of polylactic acid fiber is preferable from the viewpoint of biodegradability.
The total fineness of the multifilament yarn is usually 75 to 2,000 dtex, preferably 150 to 1,500 dtex, and the total number of filaments is usually 75 to 2,000 filaments, preferably 150 to 1. 500 filaments.
The synthetic filament multifilament yarn is woven into a woven fabric by a conventional method, and a bag is formed using the woven fabric. At this time, the structure and density of the fabric are not particularly limited, but in the present invention, first, the cover factor (CF) of the fabric calculated by the above formula (1) needs to be 1,900 or more. is there. When the cover factor of the woven fabric is less than 1,900, the density of the woven fabric is low, so that only the moisture contained in the contaminated soil is allowed to permeate out of the bag body, thereby leaving harmful substances attached to the contaminated soil inside the bag body. It becomes difficult.
The cover factor (CF) is preferably 2,000 to 2,700.
The cover factor (CF) can be appropriately adjusted according to the fineness and density of the warp and weft constituting the woven fabric as is apparent from the above formula (1).
[0007]
It is important that the air permeability of the woven fabric is 10 cc / cm ² / sec or less. When the air permeability exceeds 10 cc / cm ² / sec, it is difficult to leave harmful substances attached to the contaminated soil in the bag, as described above. Although the reason for this is not clear, it is thought that the fluid passage tendency represented by the air permeability is closely related to the filtration tendency of the suspended solids.
The air permeability is preferably 0.01 to 8 cc / cm ² / sec.
The air permeability of the woven fabric can be adjusted by the shrinkage rate when shrinking the woven fabric, calendar processing, resin processing, or a method of laminating a porous film.
[0008]
Furthermore, when the above-mentioned woven fabric is made into a bag and filled with contaminated soil, it is easily affected by moisture contained in the soil. From such a viewpoint, the wet elongation of the woven fabric needs to be 15% or less, and preferably 10% or less. More preferably, it is 5 to 10%.
Here, the wet elongation represents the elongation of the fabric under the tension (Y) calculated by the above formula (2), and is a value assuming use as a bag in a wet state. The tension (Y) calculated by the above formula (2) is shown in Fig. 3-5 on page 109 of "Improved Construction Method Manual for Promoting Utilization of Generated Soil" issued by the Civil Engineering Research Center in December 1997. It is calculated from -8.
The wet elongation can be adjusted by the intrinsic viscosity of the polymer when the yarn constituting the woven fabric is manufactured, the spinning speed, the stretching temperature, the stretching ratio, or the like.
[0009]
As described above, in the present invention, the woven fabric is formed into a bag. A conventionally well-known thing can be arbitrarily employ | adopted as a shape of a bag body. In the present invention, after the contaminated soil containing the harmful substance is put in the bag body, moisture contained in the contaminated soil in the bag body is permeated to the outside of the bag body to dehydrate, and the harmful soil adhered to the contaminated soil By leaving the substance in the bag, it can be contained in the bag.
[0010]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
In the examples,% is based on weight unless otherwise specified.
Moreover, each characteristic in an Example was evaluated in accordance with the following method.
(1) Cover factor of woven fabric From the fineness (dtex) and warp density (w / inch) of the warp constituting the woven fabric, and the fineness (dtex) and weft density (w / inch) of the woven fabric constituting the woven fabric, the above It was calculated by the formula (1).
(2) Air permeability The air permeability was measured in accordance with the fragile method defined in the JIS L 1096 method A.
(3) Elongation when wet The elongation when wet of the fabric under the tension (Y) calculated by the above formula (2) was measured according to JISL1096.
(4) Containment rate of harmful substances The amount of dioxins contained in the bottom material contained in the bag (pg-TEQ / g) is changed to the amount of dioxins contained in the bottom material filled in the bag (pg-TEQ / g). Expressed as a percentage of g).
(5) Contaminant concentration Measured according to “Measurement method of dioxins and coplanar PCB in industrial water and industrial wastewater” defined in JIS K0312.
[0011]
Example 1
Dimethyl terephthalate and ethylene glycol were transesterified and then polycondensed to obtain a polyethylene terephthalate polymer having an intrinsic viscosity of 0.64 dl / g. This polymer was heated to 220 ° C. under reduced pressure to perform solid phase polymerization to obtain a polymer having an intrinsic viscosity of 0.98 dl / g.
After the polymer is melted at 305 ° C., it is discharged from a spinneret having a round hole of 250 holes, passed through a heated atmosphere, and stretched 1.08 times while preheating with a 74 ° C. roller. A polyethylene terephthalate multifilament yarn of 560 dtex / 250 filament was obtained.
After weaving the obtained multifilament yarn, boiling water treatment was performed to shrink the fabric, the cover factor was 2,314, the air permeability was 1.0 cc / cm ² / sec, and the wet elongation was 9%. A woven fabric with a latitude of 7% was obtained.
Next, after forming a 200 L bag body using the woven fabric, soil containing a harmful substance (water content 600%) was filled using an electric pump. As a result, it was possible to contain 99.98% or more of harmful substances, and the average concentration of the pollutants in the initial drainage was 5.5 pg-TEQ / l, which was below the reference value.
The soil used at this time has a density of 2.596, a water content ratio of 27.05%, a liquid limit of 48.9%, and a dioxin content of 790 pg-TEQ / g, which is adjusted to a water content of 600%. Using.
[0012]
Comparative Example 1
Dimethyl terephthalate and ethylene glycol were subjected to a transesterification reaction and then a polycondensation reaction to obtain a polyethylene terephthalate polymer having an intrinsic viscosity of 0.64 dl / g. This polymer was heated to 220 ° C. under reduced pressure to carry out solid phase polymerization to obtain a polymer having an intrinsic viscosity of 0.98 dl / g.
After the polymer is melted at 310 ° C, it is discharged from a spinneret having a round hole of 250 holes, passed through a heated atmosphere, and then stretched 5.4 times while preheating with a 100 ° C roller. 1,100 dtex / 250 filament polyethylene terephthalate multifilament yarn was obtained.
The obtained multifilament yarn was twisted (60 T / m) and then woven at a density of 26 yarns / inch, with a cover factor of 1,644, an air permeability of 17.8 cc / cm ² / sec, and a wet elongation. Both obtained 5% woven fabric.
Next, a bag body having the same size as that of Example 1 was formed using the woven fabric, and then soil (water content 600%) containing the same harmful substances as Example 1 was filled using an electric pump. As a result, although it was possible to contain 99.43% or more of harmful substances, the average concentration of the pollutants in the wastewater was 860 pg-TEQ / l, which greatly exceeded the standard value.
[0013]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, a bag that can be suitably used for containment of contaminated soil that can efficiently filter contaminated soil with a high water content accumulated in rivers, lakes, and the like to a level that does not require wastewater treatment. And a method for containing contaminated soil using the bag.

Claims (4)

A bag body for containing contaminated soil containing harmful substances, the bag body comprising a multifilament yarn of synthetic fiber, and a cover factor (CF) calculated by the following formula (1) is 1, 900 or more, formed from a woven fabric having an air permeability of 10 cc / cm ² / sec or less and a woven fabric having a wet elongation under a tension (Y) calculated by the following formula (2) of 15% or less. A bag for containing contaminated soil.
Cover factor (CF) = {fineness of warp constituting woven fabric (dtex) × 0.9} ^1/2 × {warp density of woven fabric (lines / inch)} + {fineness of weft constituting woven fabric (dtex) × 0.9} ^1/2 × {weft density of fabric (lines / inch)} ……… (1)
Tension (Y) = 1.64X ² + 1.11X [N / cm] (2)
[In Formula (2), X represents the perimeter (m) of a bag. ] The bag for containing contaminated soil according to claim 1, wherein the multifilament yarn of synthetic fiber is a multifilament yarn made of at least one synthetic fiber selected from the group consisting of polyester, nylon, vinylon and polypropylene. The bag body for containing contaminated soil according to claim 1 or 2, wherein the multifilament yarn of synthetic fiber is a multifilament yarn made of polylactic acid fiber. After putting contaminated soil containing harmful substances into the permeable bag body, the moisture contained in the contaminated soil inside the bag permeates out of the bag body to dehydrate, and harmful substances attached to the contaminated soil are put into the bag body. A method for containing contaminated soil, comprising using the bag for containing contaminated soil according to any one of claims 1 to 3 as the bag when the bag is left to be contained in the bag.