JP2005224760A - Soil and ground water processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soil and ground water processing method reversibly provided with a means for adding a substance that oxidizes and reduces trichloroethylene or the like from the above-ground into the soil and ground water and a means for moving the substances from the soil and ground water to the above-ground. <P>SOLUTION: After organic materials existing as solids in the soil and the ground water are added to the soil and ground water, the organic materials are moved by the means for moving the substance from the soil and ground water to the above-ground. After the substance that oxidizes and reduces the organic materials existing in the soil and ground water as the solids or trichloroethylene or the like is once added to the soil and ground water, if these substances need to be removed for any reason, they can be easily removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to a soil and groundwater treatment method for purifying an organic chlorine compound such as trichlorethylene in situ.

The conventional soil and groundwater treatment methods for purifying organochlorine compounds such as trichlorethylene in situ are the substances that oxidize and reduce trichlorethylene and the like in the soil and groundwater, as disclosed in Patent Document 1 and Patent Document 2. This was an irreversible addition method.
JP 2001-347280 A Japanese Patent Laid-Open No. 10-263522

  In these conventional techniques, once substances that oxidize or reduce trichlorethylene or the like are once added to soil or groundwater, it is practically difficult to remove these substances. There was the problem of leaving the risk of secondary contamination with these substances.

  The present invention effectively solves these conventional problems, means for adding a substance that oxidizes and reduces trichlorethylene and the like from the ground to the soil and groundwater, and means for moving the soil from the groundwater to the ground. The present invention provides a soil and groundwater treatment method provided with reversibly.

  In order to solve these conventional problems, the present inventors have intensively researched and found that the following means can be used to effectively solve the problems of the present invention, and the present invention has been completed.

That is, the soil and groundwater treatment method of the present invention has the following main requirements. 1. A soil or groundwater treatment method in which organic matter that exists as a solid in soil or groundwater is added to the soil or groundwater, and then the organic matter is moved by means of moving the soil or groundwater to the ground.
2. After adding an organic substance existing as a solid in soil or groundwater by an adding means for adding to the soil or groundwater, the organic substance is transferred from the soil, groundwater to the ground using the adding means, or groundwater Processing method.
3. After adding an oxidizing or reducing inorganic substance to the soil or groundwater from the ground, the oxidizing or reducing inorganic substance is moved to the ground by means of moving the ground from the soil or groundwater. , Soil or groundwater treatment methods.
4). After adding an oxidizing or reducing inorganic substance to the soil or ground water from the ground, the adding means is used to add the oxidizing or reducing inorganic substance from the soil or ground water. Soil or groundwater treatment method that moves soil to the ground.

  With the above configuration, the soil and groundwater treatment method of the present invention once adds a substance that oxidizes and reduces organic matter or trichlorethylene that exists as a solid in the soil and groundwater once to the soil and groundwater, and then for some reason If it needs to be removed, it can be easily realized.

  Moreover, it becomes possible to control the elution amount of the organic matter by providing means for superheating the organic matter present as a solid in the soil and groundwater.

    Hereinafter, the best mode for carrying out the present invention will be described in detail.

  The organic substance that exists as a solid in the soil and groundwater used in the present invention generally refers to an organic substance that is not readily soluble in water, preferably a fatty acid having 10 or more carbon atoms, or an alcohol or biodegradable resin having 12 or more carbon atoms. It is.

  Examples of fatty acids that satisfy the above requirements include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, lignoceric acid, behenic acid, and mixtures, salts, hydrogenated products, and the like of these fatty acids.

  As the mixture, simple fatty acids may be artificially mixed, or natural mixtures such as beef tallow fatty acid, coconut oil fatty acid, palm oil fatty acid, rapeseed oil fatty acid may be used. Further, beef tallow, pork tallow, cacao butter, coconut oil, palm oil, palm kernel oil, rapeseed and the like containing the fatty acid are also included.

  Examples of the alcohol that satisfies the above requirements include lauryl alcohol, myristyl alcohol, stearyl alcohol, cetyl alcohol, behenyl alcohol, and mixtures and salts of these alcohols.

  As a mixture, a simple alcohol may be artificially mixed or a natural mixture may be used.

  Furthermore, a biodegradable resin that satisfies the above requirements is a biodegradable resin having an ester bond from the viewpoint of biodegradability, and specific examples thereof include lactic acid polymers, hydroxybutyric acid and hydroxyvaleric acid. Examples include polymers, condensation polymers of polyols and aliphatic dicarboxylic acids, poly (ε-caprolactone), and the like.

    These organic substances are biodegraded little by little in the soil and groundwater, and the biodegradation products produced at that time are in small quantities. Release to groundwater environment.

    Since these biodegradation products are readily soluble in water, microorganisms that contribute to purification easily utilize these biodegradation products and detoxify contaminants such as trichlorethylene by dechlorination.

  Means for adding organic matter existing as solid in the soil and groundwater used in the present invention from the ground to the soil and groundwater and means for moving the soil and groundwater from the ground to the physical opening of the organic matter such as a well All the means that can be added from the section, representative examples include a method of adding the organic matter in a container or bag-like container and connecting the string or rod in a connected state, a rod-like substance directly connected to the organic matter Or the method of adding using a string-like substance is illustrated.

  Specific examples of these containers and bags include metal containers, bag-shaped woven fabrics, bag-shaped nonwoven fabrics, and synthetic resin nets.

The inorganic substance having oxidizing or reducing properties used in the present invention refers to all substances that express oxidizing and reducing properties in soil and groundwater. Representative examples include iron, iron compounds such as ferrous sulfate, excess Examples include potassium manganate and hydrogen peroxide.

  These inorganic substances having oxidation or reduction properties are detoxified by oxidizing or reducing trichlorethylene or the like by oxidation or reduction reaction in soil or groundwater.

  Examples of means for heating organic substances present as solids in the soil and groundwater used in the present invention include a method of heating with electric energy such as a heater, a method of using heat generated when lime and water are in contact, and the like.

  By heating the organic matter, the solubility of the organic matter can be improved, and a soil and groundwater treatment method more suitable for the field can be provided.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
(Example 1)
A 65% by weight stearic acid and 35% by weight palmitic acid composition as an organic substance present as a solid in soil and groundwater was heated and melted at 85 ° C. and then cooled to obtain a uniform composition.

    The obtained uniform composition was mechanically pulverized to a diameter of about 2 mm, mixed with 40% by weight of calcium carbonate based on the total weight, and then extruded using an extrusion granulator (die diameter 3 mm, die temperature 40 ° C.). A cylindrical pellet having a length of about 5 mm was obtained.

    After adding 500 g of the obtained pellets to a cylindrical container (diameter 40 mm, total length 450 mm) made of a metal net (aperture 1 mm square, made of SUS304), and connecting the cylindrical containers 5 consecutively, the uppermost cylindrical container A string having a length of 10 m was connected to the ground and added to the groundwater from an observation well having an inner diameter of about 50 mm.

    The concentration of volatile organochlorine compounds in the added groundwater is 0.3 ppm by default for trichlorethylene, and after 35 days, the pellets added to the cylindrical container are taken out to the ground by pulling the string, and water is collected from the observation well. When the trichlorethylene concentration was measured and decreased to about 0.07 ppm, the environmental standard was not reached. Therefore, the pellet added to the cylindrical container was added again from the observation well, and the purification was continued.

    Thereafter, after 42 days (77 days from the beginning), water was collected from the observation well in the same manner as after 35 days, and the trichlorethylene concentration was measured to be about 0.01 ppm. .

As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.
(Example 2)
As an organic substance present as a solid in soil and groundwater, a 85% by weight myristyl alcohol and 15% by weight beef tallow fatty acid composition was heated and melted at 85 ° C. and then cooled to obtain a uniform composition.

    The obtained uniform composition was mechanically pulverized to a diameter of about 2 mm, mixed with 40% by weight of calcium carbonate based on the total weight, and then extruded using an extrusion granulator (die diameter 3 mm, die temperature 40 ° C.). A cylindrical pellet having a length of about 5 mm was obtained.

After adding 850 g of the obtained pellets to a cylindrical bag (diameter: about 35 mm, total length: 100 mm) made of a nonwoven fabric (weighing 180 g / m 2, made of polyester), and connecting three cylindrical bags, the uppermost cylinder A rope with a length of 10 m was connected to the shaped bag and added to the groundwater from an observation well with an inner diameter of about 50 mm.

The concentration of volatile organochlorine compounds in the added groundwater is 1.2 ppm by default for trichlorethylene. After 35 days, the pellets added to the cylindrical bag are taken out to the ground by pulling up a rope and taken from the observation well. When the water trichlorethylene concentration was measured and found to be about 0.01 ppm, the environmental standard value was cleared, so the purification work was completed.
As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.
(Example 3)
A cylinder composed of polylactic acid resin pellets (cylindrical shape with a diameter of about 1.5 mm and a length of about 3 mm) made of a synthetic resin net (opening 1 mm square, made of polypropylene) as organic matter that exists as a solid in soil and groundwater 500 g was added to a container (diameter 40 mm, total length 450 mm), and the cylindrical containers were connected in series to a series of five. After that, a string of 10 m in length was connected to the uppermost cylindrical container and added to groundwater from an observation well with an inner diameter of about 50 mm .

    The concentration of volatile organochlorine compounds in the added groundwater is 0.5 ppm by default for tetrachlorethylene. After 33 days, the pellets added to the cylindrical container are taken out to the ground by pulling up the string, and water is collected from the observation well. Since the tetrachlorethylene concentration was measured to be about 0.09 ppm, it was judged that the soil and groundwater treatment method of the present invention (generally referred to as anaerobic biomethod) was applicable.

As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a treatment method that allows easy applicability evaluation of anaerobic biomethods.
Example 4
2.5 kg was added to a bag (diameter: 40 mm, overall length: 450 mm) composed of iron powder (average particle diameter of about 0.8 micrometer) as a non-reducing inorganic material bag (mesh size: 320 g / m2). It was connected to a 10 m long string and added to groundwater from 11 observation wells having an inner diameter of about 50 mm.

    The concentration of volatile organochlorine compounds in the added groundwater is 0.5 ppm by default for trichlorethylene. After 30 days, the iron powder added to the bag is taken out to the ground by pulling the string, and water is collected from the observation well. However, although the trichlorethylene concentration was reduced to about 0.08 ppm, it did not reach the environmental standard, so the iron powder added to the bag was added again from the observation well and the purification was continued.

    Thereafter, after 55 days (85 days from the beginning), water was collected from the observation well in the same procedure as that after 30 days, and the trichlorethylene concentration was measured to be about 0.01 ppm. .

As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.
(Example 5)
Fatty acid shown in FIG. 1 is obtained by melting beef tallow fatty acid as a solid in soil and groundwater to 80 ° C., pouring it into a cylindrical mold having an iron core rod 1 in the center, and solidifying it at room temperature. A solid material (diameter 40 mm, total length 1 m) 2 fixed to the periphery of the iron core rod 1 was obtained.

    The obtained fatty acid solid 2 was added to groundwater from an observation well having an inner diameter of about 50 mm, and purification was started.

The concentration of volatile organochlorine compounds in the added groundwater is 0.9 ppm by default for trichlorethylene, and after 25 days, the core rod was pulled out and taken out to the ground. However, since the environmental standard value was cleared at about 0.01 ppm, the purification work was completed.
As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.
(Example 6)
By melting stearic acid at 80 ° C as an organic substance that exists as a solid in soil and groundwater, it is poured into a cylindrical mold 5 in which an iron core rod 3 with a built-in heater is placed in the center and solidified at room temperature. The thing which fixed the fatty-acid solid substance (diameter 40mm, full length 1m) 4 shown in 2 to the circumference | surroundings of an iron core rod was obtained.

    The obtained fatty acid solid was added to groundwater from an observation well having an inner diameter of about 50 mm, and purification was started.

    For 10 days after the start of purification, the heater was energized and the core rod was heated to increase the solubility of stearic acid, thereby increasing the amount of organic matter to the surroundings.

    Thereafter, the solubility was controlled to 1/4 of the initial 10 days for 20 days (heater current was controlled to about 1/3).

    The concentration of volatile organochlorine compounds in the added groundwater is 8.4 ppm by default for trichlorethylene, and after 88 days, the core rod is pulled out to the ground, taken from the observation well, and the trichlorethylene concentration is measured. However, since the environmental standard value was cleared at about 0.01 ppm, the purification work was completed.

    As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.

Furthermore, it is a processing method capable of controlling the amount of fatty acid dissolved by controlling the heater energization amount.
(Example 7)
A 65% by weight stearic acid and 35% by weight palmitic acid composition as an organic substance present as a solid in soil and groundwater was heated and melted at 85 ° C. and then cooled to obtain a uniform composition.

    The obtained uniform composition was mechanically pulverized to a diameter of about 2 mm, mixed with 55% by weight of quick lime based on the total weight, and then extruded with an extrusion granulator (die diameter: 3 mm, die temperature: 40 ° C.). A cylindrical pellet having a thickness of about 5 mm was obtained.

    After adding 500 g of the obtained pellets to a cylindrical container (diameter 40 mm, total length 450 mm) made of a metal net (aperture 1 mm square, made of SUS304), and connecting the cylindrical containers 5 consecutively, the uppermost cylindrical container A string having a length of 10 m was connected to the ground and added to the groundwater from an observation well having an inner diameter of about 50 mm.

    The concentration of volatile organic chlorine compounds in the added groundwater is 0.5 ppm by default for trichlorethylene, and after 35 days, the pellets added to the cylindrical container are taken out to the ground by pulling up the string, and water is collected from the observation well. However, although the trichlorethylene concentration was reduced to about 0.1 ppm, it did not reach the environmental standard, so the pellet added to the cylindrical container was added again from the observation well, and the purification was continued.

    Thereafter, after 41 days (76 days from the beginning), water was collected from the observation well in the same manner as after 35 days, and the trichlorethylene concentration was measured to be about 0.01 ppm. .

    Fever was observed in the reaction of quicklime and water throughout the purification period, and it was possible to effectively improve the solubility of the stearic acid and palmitic acid compositions.

    As described above, the soil and groundwater treatment method of the present invention can reversibly provide means for moving the soil and groundwater to the ground and means for adding the soil and groundwater, and can easily return to the current state. It is a processing method.

  The purification composition according to the present invention can be used for purification of soil and groundwater containing an organic chlorine compound.

The perspective view of the fatty-acid composition used for the 5th Example of this invention Sectional drawing of the fatty acid composition used for the 6th example of the present invention.

Explanation of symbols

1 Iron core 2 Fatty acid solid 4 Fatty acid solid

Claims (17)

A soil or groundwater treatment method in which organic matter that exists as a solid in soil or groundwater is added to the soil or groundwater, and then the organic matter is moved by means of moving the soil or groundwater to the ground. After adding an organic substance existing as a solid in soil or groundwater by an adding means for adding to the soil or groundwater, the organic substance is transferred from the soil, groundwater to the ground using the adding means, or groundwater Processing method. After adding an oxidizing or reducing inorganic substance to the soil or groundwater from the ground, the oxidizing or reducing inorganic substance is moved to the ground by means of moving the ground from the soil or groundwater. , Soil or groundwater treatment methods. After adding an oxidizing or reducing inorganic substance to the soil or ground water from the ground, the adding means is used to add the oxidizing or reducing inorganic substance from the soil or ground water. Soil or groundwater treatment method that moves soil to the ground. The soil and groundwater treatment method according to claim 1 or 3, wherein the means for moving is a metal container. The soil and groundwater treatment method according to claim 2 or 4, wherein the means for adding is a metal container. The soil and groundwater treatment method according to claim 1 or 3, wherein the moving means is a bag-like woven fabric, non-woven fabric, or synthetic resin net. The soil and groundwater treatment method according to claim 2 or 4, wherein the means for adding is a bag-like woven fabric, non-woven fabric, or synthetic resin net. The soil and groundwater treatment method according to claim 1 or 3, wherein the means for moving is a rod or string connected to an organic substance present as a solid in the soil or groundwater. The soil and groundwater treatment method according to claim 2 or 4, wherein the means to be added is a rod-like material or a string-like material connected to organic matter present as a solid in the soil or groundwater. The processing method of the soil and groundwater of Claim 1 which has the process of heating the said organic substance in soil or groundwater. The soil and groundwater treatment method according to 11, wherein the heating means is a heater using electric energy. The soil and groundwater treatment method according to 11, wherein the heating means allows lime to coexist. The soil or groundwater treatment method according to any one of claims 1 and 11, wherein the organic matter present as a solid in the soil and groundwater contains a fatty acid having 10 or more carbon atoms as a main component. The soil and groundwater treatment method according to any one of claims 1 and 11, wherein an organic substance present as a solid in the soil and groundwater contains an alcohol having 12 or more carbon atoms as a main component. The soil and groundwater treatment method according to claim 1 or 11, wherein the organic matter present as a solid in the soil and groundwater is a biodegradable resin. The soil or groundwater treatment method according to claim 1 or 11, wherein the inorganic substance having oxidizing or reducing properties is selected from iron, an iron compound, and potassium permanganate.

Images