JP2010012445A - Method for treating contaminated soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating contaminated soil in which soil contaminated with toxifying materials can be treated in an actual spot by cleaning the soil particles of the contaminated soil, and to provide its device. <P>SOLUTION: After a plurality of hollow pipes 1 made of a metal which bore a large number of water-through openings 2 which are served as the electrodes of anode and cathode are installed in the contaminated soil G deeper than the depth of the contaminated soil and facing to the anode and the cathode, the cleaning water is sufficiently permeated into the contaminated soil G by suitably sprinkling the cleaning water onto the upper surface of the contaminated soil G. Thereafter, a direct electric current is turned on to the respective electrodes to be loaded with the DC voltage, electric osmotic phenomena are produced in the contaminated soil G between both the electrodes, the cleaning water is speedily flowed from the anode direction to the cathode direction, contaminated water in gap between the soil particles or dissolving water dissolving contaminated materials is moved together to gather them through the water-through openings 2 of the cathode ray tube. The quality of water is inspected and the cleaning of the contaminated soil G is repeated until reaching the predetermined water quality. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention is used for soils contaminated with heavy metals such as hexavalent chromium and benzene, lead, mercury, etc. discharged from smelters and plating plants that are substances causing pollution, or for dry cleaning and metal cleaning. The present invention relates to a method for treating contaminated soil, in which soil contaminated with harmful substances such as tetrachloroethylene is used as it is, and soil particles of the contaminated soil are washed to treat the contaminated soil.

Pollutant pollutants leaked from the factory premises of various industries or from factory equipment are washed away around the factory or penetrated underground to contaminate the soil in the surrounding area, or soil is contaminated by harmful substances leached from industrial waste. Conventionally, when contaminated, a method of removing contaminated soil and replacing it with new soil, or removing contaminated water in the soil by a vacuum method or the like has been implemented.

On the other hand, when a past patent document is retrospectively searched for a method of processing contaminated soil in situ, the one described in Patent Document 1 below is known.

Japanese Patent Publication No. 7-87912

As the conventional contaminated soil treatment method, the soil in the contaminated area is removed and replaced with new soil, or a method of removing contaminated water in the soil by a vacuum method or the like has been used. In addition to the problem of causing secondary pollution to surrounding residents for the purpose of carrying out and carrying in earth and sand, there was a problem that the contaminated soil that had been carried out had to be further detoxified.

Furthermore, for example, in an industrial area of a landfill that is composed of fine-grained soil, the ground that is composed is an area that consists of very small soil particles, and the permeability of the soil is low, There was a problem that there were many grounds not applicable to the vacuum method.

Furthermore, the construction method described in Patent Document 1 includes a first step of constructing a water-impervious wall around a contaminated soil area, and a plurality of water holes having a plurality of water holes that serve as anode and cathode electrodes. A hollow tube is formed on the contaminated soil so as to face the anode and cathode, and is arranged so that the polarity of the anode and cathode can be changed, and water is appropriately sprinkled in the contaminated soil area. Then, a direct current is passed through each of the electrodes to cause an electroosmotic phenomenon in the contaminated soil between the two electrodes, so that the pollutants in the soil are in the liquid phase from the anode direction. Flow in the cathode direction, collect water in the cathode tube through the water passage hole, pump it up and purify it, and clean in the anode tube after pumping up contaminants in the second step Water is injected and a direct current is applied to each electrode to cause electroosmosis in the contaminated soil between the electrodes. By soaking, the cleaning water in the anode tube permeates and flows into the soil from the water passage hole of the tube, and dissolves or entrains the contaminated interstitial water between the soil particles or contaminates the contaminated soil. The third step of washing and flowing into the cathode side tube through the water passage hole, pumping it up, performing a water quality test, and washing and washing until a prescribed water quality standard is reached. Yes.

However, in the construction method described in the above-mentioned patent document, in order to construct the impermeable wall in the first step, equipment for constructing the impermeable wall is necessary and time-consuming. In the third step, cleaning water must be poured into each anode tube in the third step, which is troublesome. The cleaning water flows linearly from the water passage hole to the water passage hole of the cathode tube and flows into the water passage hole of the cathode tube. Therefore, in the contaminated soil removed from the flow passage of the washing water, There was a problem that the contaminated soil could not be completely treated because the cleaning water did not flow, and therefore contaminated soil remained uncleanable.

The present invention has been made in order to solve the above-mentioned problems. In addition to treating contaminated soil in situ, it is not necessary to construct a water shielding wall, and without injecting cleaning water into the anode tube one by one. Simply spray the cleaning water on the top surface of the contaminated soil and infiltrate the cleaning water into the contaminated soil, and then clean the contaminated soil by electroosmosis, shortening the construction period and reducing the construction cost. In addition, the present invention intends to provide a method and apparatus for treating contaminated soil that can completely treat contaminated soil.

The present invention is a metal which has a large number of water passage holes along the outer peripheral edge of a contaminated soil treatment area for treating contaminated soil, and also serves as an anode and a cathode electrode having a bottomed water storage section below. A plurality of hollow tubes made of metal are arranged at predetermined intervals deeper than the depth of the contaminated soil, and anodes and cathodes are alternately arranged in a straight line to form a square frame-like frame tube row On the other hand, in the contaminated soil treatment area surrounded by the frame-shaped tube row, the hollow tube having the same configuration as described above is installed in a straight line facing the anode and the cathode in parallel, and one set or plural Forming a set of straight tube rows, and further installing the first and second cathodes in such a manner that the polarity of the anode and the cathode can be changed; Thoroughly infiltrate into the contaminated soil, and then apply a direct current to each of the electrodes to apply a direct voltage to the electrodes. Then, an electroosmosis phenomenon occurs in the contaminated soil treatment area between the two electrodes, and a water shielding layer is formed between the soil electrodes adjacent to the contaminated soil treatment area in the soil between both electrodes of the frame-shaped tube array. In addition, the contaminated soil is treated with the cleaning water, the contaminated interstitial water between the soil particles or the dissolved water in which the contaminant is dissolved is washed with the cleaning water, and the contaminated soil is washed. The second step of collecting and storing the water in the lower water storage part in the cathode tube in the state of the phase in the state of the phase, pumping it up, performing a water quality test, and washing until a prescribed water quality standard value is reached Or the method of treating contaminated soil with
A metal hollow that serves as both anode and cathode electrodes with a large number of water passage holes along the outer periphery of the contaminated soil treatment area that contaminates contaminated soil, and has a bottomed water storage section below. While forming a square frame-like frame-like tube row by installing a plurality of tubes at a predetermined interval deeper than the depth of the contaminated soil, and for the anode and the cathode alternately opposed in a straight line, In the contaminated soil treatment region surrounded by the frame-shaped tube row, a plurality of straight tube rows are formed by installing the hollow tubes having the same configuration as described above alternately and alternately facing the anode and the cathode, Furthermore, the first step of installing the anode and the cathode so that the polarity can be changed, and the cleaning water is appropriately sprinkled on the upper surface of the contaminated soil treatment area to sufficiently permeate the cleaning water into the contaminated soil, Then, a direct current is applied to each of the electrodes, a direct current voltage is applied to each of the electrodes, and the contaminated soil treatment between the two electrodes is performed. In the soil between the two electrodes of the frame-shaped tube row, an electroosmosis phenomenon is caused in the region, and a water shielding layer is formed between the soil adjacent to the contaminated soil treatment region, and the contaminated soil treatment region On the entire surface, the cleaning water entrains contaminated pore water between soil particles or dissolved water in which the pollutant is dissolved to wash the contaminated soil, and the pollutant is passed through the water passage hole in a liquid state. Through the second step of collecting and storing water in the water storage section below the cathode tube, pumping it up, conducting a water quality test, and cleaning until it reaches the specified water quality standard value. ,
By realizing one of the above, the above-described problems have been solved.

According to the treatment method of the present invention, in the contaminated soil treatment area, a hollow tube serving as an electrode is installed deeper than the depth of the contamination, and cleaning water is sprinkled on the upper surface of the contaminated soil treatment area, and the hollow When a direct current is applied to each of the anode and cathode electrodes made of a tube and a DC voltage is applied to each of the electrodes, the contaminated soil is treated only in the area surrounded by the anode and cathode electrodes. Since the electric conduction phenomenon acts in the area, pollutants dissolved in water do not flow to areas outside this range, and were adsorbed in an electric double layer on fine soil particles with low permeability such as clayey soil Contaminant water or liquid phase can be easily moved into the cathode side tube by its electrokinetic action and collected to collect contaminated soil. Clean the contaminated soil in place without replacing the soil It is possible to sense. In addition, by installing the anode and cathode hollow tubes facing each other in a square frame shape along the outer periphery of the contaminated soil treatment area, the soil between the two electrodes of the square frame tube row is placed in the soil. Since a water-impervious layer can be formed by generating an electroosmosis phenomenon, it is not necessary to install a water-impervious wall as in the conventional case, and the construction period can be shortened and the cost can be reduced. It is possible to prevent clogging.

When decontaminating contaminated soil at the current location, first, an inspection specialist bores multiple locations in the contaminated soil, collects multiple soils for inspection, and how deep the soil is. And what substances are contaminated. And the test result by the said inspection expert is obtained, and the process of the contaminated soil by the method of this invention is started.

After the depth of contamination of the contaminated soil and the contaminants are specified by the inspection specialist, the processing of the contaminated soil of the present invention is started. Depending on the size of the contaminated soil area and the shape of the site, the entire contaminated soil area Is treated as a contaminated soil treatment area in a lump, or is divided into contaminated soil treatment areas, and the contaminated soil treatment work of the present invention is performed. In the case where the contaminated soil area is divided to work, the contaminated soil treatment of the present invention can be performed simultaneously on the divided contaminated soil treatment area. It will be explained as being implemented in the region. In addition, when collectively processing without dividing the contaminated soil area, the processing method is different from the case of processing the divided contaminated soil processing area in this embodiment only in whether the processing area is wide or narrow. Are completely the same, and the description is omitted.

The 1st process of the processing method of this invention contaminated earth is a hollow pipe installation process used as the electrode to the divided contaminated earth processing area. In the first step, the hollow tube is installed in the contaminated soil treatment area with a large number of small holes, slits, or small holes that serve as anode and cathode electrodes from the outer periphery of the four circumferences to the entire inner surface. A water hollow formed by a combination of a hole and a slit is drilled, and a metal hollow pipe having a bottomed water storage portion is formed deeper than the contaminated soil contamination depth in the contaminated soil treatment area, and In this step, the anode and the cathode are arranged in a plurality of rows at a predetermined interval so that the anode and the cathode face each other in parallel.

When the hollow tube installation step in the first step is completed, the contaminated soil washing step in the second step is started. In the contaminated soil cleaning process of the second step, cleaning water composed of tap water, fresh water, or water mixed with a solvent of pollutants is sprinkled on the upper surface of the contaminated soil treatment area, and the cleaning water is put into the contaminated soil treatment area. Then, when a direct current is applied to both the electrodes and a direct current voltage is applied to both the electrodes, an electromagnetic field is formed in the ground between the two electrodes. Electro-osmosis phenomenon during electrokinetic phenomenon occurs in the contaminated soil during the period, and the cations around the negatively charged soil particles and the free water in the soil gap move from the anode direction to the cathode direction by the electro-osmosis phenomenon. Move quickly through the soil.

Using the electrochemical flow of washing water in the soil, the heavy metals adsorbed between the fine soil particles or around the soil particles and other pollutants are electrochemically separated, Contaminated pore water between soil particles or dissolved water dissolving dissolved contaminants is taken from the anode direction to the cathode direction to clean the contaminated soil in the contaminated soil treatment area. In the liquid phase, the water is stored in the water storage part provided under the cathode tube through the water passage hole of the cathode tube, and after that, it is pumped up by a pump or the like to conduct a water quality test, and the specified water quality When the reference value is reached, the cleaning process of the second process is completed, and the contaminated soil treatment work is completed.

As a result of pumping up the washing water after washing the pollutant and checking the water quality, if still higher than the specified water quality standard value, again spray the washing water such as tap water or fresh water into the contaminated soil treatment area, Repeat the second step. In addition, when the washing water after washing, which has been pumped up, is lower than the prescribed water quality standard value, the waste water can be treated as it is. However, if the washing water after washing is higher than the specified water quality standard value, add the solvent to the pumped washing water or filter it to below the prescribed water quality standard value, and then perform the waste water treatment. There is a need to.

Hereinafter, each of the contaminated soil treatment methods will be described in detail with reference to the drawings. The hollow tube installation step of the first step is a step of installing in the contaminated soil G in the contaminated soil treatment area × 1 obtained by dividing the hollow tube 1 that also serves as an anode and a cathode.

In other words, the soil engineering characteristics of the soil in the contaminated soil G area are investigated, and the average permeability of the soil that constitutes the ground is used as a reference, and the metal is used as both anode and cathode. A plurality of hollow tubes 1 having a circular or polygonal shape have a predetermined interval so as to follow the outer peripheral edge of the contaminated soil treatment area × 1 and are deeper than the depth of the contaminated soil G, and the anode and cathode The hollow tubes 1 are installed in a rectangular frame shape so as to alternately oppose each other in a straight line to form a frame-shaped tube row R, and the contaminated soil treatment area surrounded by the frame-shaped tube row R × In the same manner as described above, a plurality of hollow tubes 1 for the anode and the cathode are linearly arranged at a predetermined interval deeper than the depth of the contaminated earth G and facing each other in parallel. Installed to form one or a plurality of sets of straight tube arrays A and B of anode and cathode (see FIGS. 1 and 2).

In each of the hollow tubes 1, each of the hollow tubes 1 can collect the cleaning water sprinkled in the contaminated soil treatment area × 1 described later in the hollow tubes 1 in the ground. Is preferably a small hole 2a (FIG. 3) having a width of about 3 to 8 mm, a slit 2b having a width of about 5 mm and a length of about 5 cm (FIG. 4), or a combination of the small hole 2a and the slit 2b (see FIG. 5) is formed with a constant opening ratio, and a connecting device 4 such as an electric connecting terminal is attached to a portion protruding from the ground surface of each hollow tube 1. Further, a bottomed water storage section 3 capable of storing the cleaning water collected in the hollow pipe 1 is provided at a lower portion of each hollow pipe 1.

In the contaminated soil treatment area × 1 of the contaminated soil G, the anode-side hollow tubes 1 of the frame-like tube row R and the anode-side straight tube rows A installed as anode and cathode electrodes Connected to each connection device 4 projecting from the ground surface of each hollow tube 1 is a cord 6 on the anode side of the DC power source 5, and the cathode side hollow tube 1 of the frame-shaped tube row R and the straight side on the cathode side. A cord 7 on the cathode side of the DC power source 5 is connected to each connection device 4 in the tube row B. In FIG. 2, the frame-shaped tube row R is illustrated, and in the contaminated soil treatment area × 1 surrounded by the frame-shaped tube row R, four sets of straight tube rows A and B are installed. However, if the processing area is large, more straight tube rows are installed.

After the installation of each hollow tube 1 in the first step, the second step of the contaminated soil cleaning step is entered. Using a sprinkler or the like in the contaminated soil treatment area × 1 of the contaminated soil G, water for cleaning such as tap water or fresh water is appropriately sprinkled, and the water for cleaning is infiltrated into the contaminated soil G. A direct current is supplied from a direct current power source P through a connecting device 4 mounted on a portion of the hollow tube 1 that protrudes from the ground surface. The empty tube 1 is loaded with a DC voltage.

By applying a DC voltage to each electrode of the frame-shaped tube row R and the straight tube rows A and B, the straight tube row A and the cathode between the anode and the cathode of the frame-shaped tube row R and the anode side are provided. In the inside of the contaminated soil G between the anode and the cathode of the straight tube row B on the side, an electroosmosis phenomenon during the electrokinetic phenomenon occurs, and the contaminant in the contaminated soil G is in a liquid phase state. From the direction to the cathode direction, it flows and moves quickly with a certain directionality.

In this case, the cleaning water after cleaning the contaminants between the soil particles with the sprayed cleaning water, and the cleaning water after cleaning and separating the contaminants adsorbed on the soil particles are also shown in the figure. As indicated by the arrows, the particles move quickly between the soil particles from the direction of the anode to the direction of the cathode and with a large contact area with the contaminated soil. Since the hollow tubes 1 having the water passage holes 3 are used as the respective electrodes, the cleaning water after washing easily passes through the water passage holes 2 in the hollow tubes 1 on the cathode side. Then, the water is collected and stored in the water storage part 3 provided in the lower part of the lowermost water passage hole 2 of each hollow tube 1 on the cathode side.

Then, the water for cleaning after being collected and stored in the water storage section 3 below the hollow tubes 1 on the cathode side, that is, the cleaning water containing contaminants, is stored in each hollow tube 1 on the cathode side. If the water quality is higher than the specified standard value as a result of water quality inspection by pumping up from the top opening of the pump with a pump or vacuum device (not shown), tap water or clean water such as fresh water is sprinkled again into the contaminated soil treatment area. Then, the second step is repeated until the water quality falls below a prescribed water quality standard value. In addition, when the washing water after washing that is pumped up is higher than a prescribed water quality standard value, it is possible to add a solvent to the washing water or filter it to perform a wastewater treatment below the water quality standard value. .

In collecting the washing water after washing in the second step, if the electrode polarity remains the same for a long time, a polarization phenomenon occurs and the water collecting ability is reduced. The polarity of each hollow tube 1 that also serves as an electrode is changed, and the current anode side is changed to the cathode side, and the previous cathode side is changed to the anode side. This polarity change stimulates the underground electrical behavior and improves the water collection capacity of the new cathode side. When this polarity switching operation is performed several times, the water content ratio in the soil is reduced, the electrical resistance of the contaminated soil G is increased, and almost no water is collected on the cathode side. At this time, the determination is made at the end of the electrokinetic phenomenon, and the construction is completed.

In FIG. 1 and FIG. 2, the washed water sprayed into the contaminated soil treatment area × 1 by the frame-shaped tube row R installed in a rectangular frame shape along the outer periphery of the four circumferences of the contaminated soil treatment area × 1. Since the water is collected in the hollow tubes 1 on the cathode side along with the cleaning water in the vicinity of the hollow tubes 1 on the anode side, the cleaning water sprayed in the contaminated soil treatment area × 1 Does not flow out of the contaminated soil treatment area × 1 or contaminated water does not flow into the contaminated soil treatment × 1 from outside the contaminated soil treatment area, and is installed in a rectangular frame shape along the outer periphery. A frame-shaped water-impervious layer W is formed in the contaminated earth G sandwiched between the anode and cathode hollow tubes 1 of the frame-shaped tube row R, and functions as a water-impervious wall described in Patent Document 1. It can be fulfilled.

That is, as shown in FIG. 1 and FIG. 2, the frame-shaped tube row R is located on both sides of the anode and the anode because the anode and the cathode are alternately arranged in a square frame shape. An electroosmosis phenomenon occurs between the soil and the cathode, and as shown by the arrows in the figure, the cleaning water moves from the anode tubes to the cathode tubes located on both sides. Since the anode tube and the cathode tube are alternately arranged in a rectangular frame shape, a rectangular frame-shaped water shielding layer W is formed in the contaminated soil G in the contaminated soil treatment area × 1 by electroosmosis, and the contaminated soil Cleaning water does not flow out of the contaminated soil treatment area × 1 from the treatment area × 1, and conversely, there is no inflow of contaminated water from outside the contaminated soil treatment area × 1.

Next, FIG. 6 is used for the case where the contaminated soil treatment in the contaminated soil treatment area × 1 is completed, and the treatment method of the present invention is performed in another contaminated soil treatment area adjacent to the treated contaminated soil area × 1. I will explain. First, when the processing of the contaminated soil in the first contaminated soil processing area × 1 is completed, the installation state of each hollow tube 1 is the state as shown in FIG.

And before moving to the processing operation of the next contaminated soil treatment area × 2, the outer peripheral edge of the contaminated soil treatment area × 1 among the hollow tubes 1 installed in the state shown in FIG. As shown in FIG. 6, the frame-shaped tube rows R installed in the rectangular frame shape are left as they are, and the hollows constituting the linear tube rows A and B other than the frame-shaped tube row R are left as they are. All the tubes 1 are removed and a DC current is applied to the frame-shaped tube row R so that an electro-osmosis phenomenon occurs, so that an electro-osmosis phenomenon occurs in the earth between each anode and cathode of the frame-shaped tube row R. The water shielding layer W is formed to prevent the contaminated water from flowing into the treated contaminated soil area × 1 from the untreated area.

After forming the water shielding layer W in the contaminated soil treatment area × 1, the contaminated soil is treated with the section adjacent to the treated contaminated soil area × 1 as the contaminated soil treatment area × 2. In this case, among the treated tube sections R of the contaminated soil area × 1, the tube array in contact with the contaminated soil treatment area × 2 is used as it is, and the side R1 of the frame tube array R of the contaminated soil treatment area × 2 is Use as a component. The other hollow tubes 1 are installed in the contaminated soil treatment area × 2 in the same manner as the contaminated soil treatment area-completed contaminated soil area × 1, and the contaminated soil is treated by the same method.

Hereinafter, similarly, as shown in FIG. 7, the contaminated soil is treated in order as in the contaminated soil treatment area × 3 to × 6, but the frame shape installed on the outer peripheral edge of each contaminated soil treatment area. When the tube row R does not face any untreated area after the processing of the adjacent contaminated soil treatment area is completed, the frame-shaped tube row R is removed.

As described above, it is not necessary to install a water-impervious wall prior to the treatment as described in Patent Document 1 by performing small contaminated soil treatment areas one after another. Then, after completion of the contaminated soil treatment work, a boundary wall may be provided with a steel sheet pile or the like, if necessary, in order to prevent the inflow of contaminated water from the adjacent land of others.

In FIG. 1, a rectangular frame-shaped tube array R is formed by alternately facing the anode and cathode hollow tubes 1 in a straight line along the outer peripheral edge of the contaminated soil treatment area × 1. In addition, in the contaminated soil treatment area surrounded by the frame-shaped tube row R, two sets of tube rows A and B are formed linearly with the anode and the cathode facing each other, as shown in FIG. In the contaminated soil treatment area, a plurality of tube rows S may be formed by alternately facing the anode and the cathode in a straight line. In this case, as shown by the arrows in FIG. 8, the cleaning water moves from the anode direction disposed in the contaminated soil treatment area to the plurality of cathode directions.

The cleaning water flows from the anode direction to the cathode direction, and the cleaning water is collected from the cathode water passage hole 2. In this case, the cleaning water is collected from the water passage hole 2 together with the contaminated soil, There is a possibility that the water passage hole 2 may be clogged due to contaminated soil, and water cannot be collected.

In the present invention, in order to prevent clogging of the cathode side hollow tube 2, when the polarity of the anode and the cathode is changed, cleaning water is supplied to the hollow tube 1 which has been the cathode side from the upper end opening. When water is injected and a DC voltage is applied to the anode and cathode, the cleaning water is discharged into the contaminated earth G from the water passage hole 2 on the anode side (previously, the cathode side), and the cathode side (so far, the anode side). Due to the electro-osmotic phenomenon, the soil is discharged from the anode tube in the opposite direction to the previous movement, so that the contaminated soil clogged in the water passage hole 2 is separated from the water passage hole 2 to eliminate clogging. can do.

As a result of the present inventor treating several contaminated earth using the method for treating contaminated earth according to the present invention, the installation interval of each hollow tube 1 is about 40 to 80 cm, and each hollow tube 1 It was confirmed that the flow from the anode side to the cathode side of the washing water in the soil was smooth when the treatment was performed by applying a low direct current of about 15 to 35 V. On the contrary, it was confirmed that when a direct current of a high voltage of 35 V or higher was passed through each hollow tube 1, the flow of cleaning water from the anode side to the cathode side did not smoothly proceed.

It is a schematic plan view which shows the example of installation of the electrode used for the processing method of this invention contaminated earth. It is the longitudinal cross-sectional view. It is the enlarged front view which notched some hollow tubes used for the method of this invention. It is the enlarged front view which notched some which show the other Example of the hollow tube used for this invention method. It is the enlarged front view which notched some which show the further another Example of the hollow tube used for this invention method. It is a schematic explanatory drawing which shows the construction example in the processing method of this invention contaminated soil. It is a schematic explanatory drawing which shows the construction example in the processing method of this invention contaminated soil. It is a schematic plan view which shows the other example of installation of the electrode used for the processing method of contaminated soil of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow tube 2 Water flow hole 2a Small hole 2b Slit 3 Water storage part 4 Connection apparatus 5 DC power supply 6 Anode side cord 7 Cathode side cord A Anode side straight tube row B Cathode side straight tube row G Contamination Soil P DC power supply R Frame tube row S Straight tube row W Impermeable layer × 1 to × 6 Contaminated soil treatment area

Claims (4)

A hollow made of metal that serves as both anode and cathode electrodes with a large number of water passage holes along the outer peripheral edge of the contaminated soil treatment area that treats contaminated soil. While forming a square frame-like frame-like tube row by installing a plurality of tubes at a predetermined interval deeper than the depth of the contaminated soil, and for the anode and the cathode alternately opposed in a straight line, In a contaminated soil treatment area surrounded by a frame-shaped tube row, a hollow tube having the same configuration as described above is installed in a straight line facing the anode and the cathode in parallel. A first row is formed so that the polarity of the anode and the cathode can be changed, and cleaning water is appropriately sprinkled on the upper surface of the contaminated soil treatment area so that the cleaning water is sufficiently contaminated soil. So that each electrode has a direct current applied thereto, a DC voltage is applied to each electrode, and both electrodes In the soil between the two electrodes of the frame-shaped tube row, forming a water-impervious layer between the soil adjacent to the contaminated soil treatment area, causing an electroosmosis phenomenon in the contaminated soil treatment area between, In the entire surface of the contaminated soil treatment area, the cleaning water entrains the contaminated pore water between the soil particles or the dissolved water in which the contaminant is dissolved to wash the contaminated soil, and the contaminant in a liquid phase state. Contaminated soil by the second step of collecting and storing water in the lower water storage part in the cathode tube through the water passage hole, pumping it up, conducting a water quality test, and washing it until a prescribed water quality standard value is reached. A method for treating contaminated soil, characterized by treating the soil. A metal hollow that serves as both anode and cathode electrodes with a large number of water passage holes along the outer periphery of the contaminated soil treatment area that contaminates contaminated soil, and has a bottomed water storage section below. While forming a square frame-like frame-like tube row by installing a plurality of tubes at a predetermined interval deeper than the depth of the contaminated soil, and for the anode and the cathode alternately opposed in a straight line, In the contaminated soil treatment region surrounded by the frame-shaped tube row, a plurality of straight tube rows are formed by installing the hollow tubes having the same configuration as described above alternately and alternately facing the anode and the cathode, Furthermore, the first step of installing the anode and the cathode so that the polarity can be changed, and the cleaning water is appropriately sprinkled on the upper surface of the contaminated soil treatment area to sufficiently permeate the cleaning water into the contaminated soil, Then, a direct current is applied to each of the electrodes, a direct current voltage is applied to each of the electrodes, and the contaminated soil treatment between the two electrodes is performed. In the soil between the two electrodes of the frame-shaped tube row, an electroosmosis phenomenon is caused in the region, and a water shielding layer is formed between the soil adjacent to the contaminated soil treatment region, and the contaminated soil treatment region On the entire surface, the cleaning water entrains contaminated pore water between soil particles or dissolved water in which the pollutant is dissolved to wash the contaminated soil, and the pollutant is passed through the water passage hole in a liquid state. Through the second step of collecting and storing water in the water storage section below the cathode tube, pumping it up, conducting a water quality test, and washing it until it reaches the specified water quality standard value. A characteristic method for treating contaminated soil. 3. The method for treating a contaminated soil according to claim 1, wherein after the contamination treatment in the contaminated soil treatment area is completed, the contaminated soil treatment in the next contaminated soil treatment area adjacent to the contaminated soil area. In performing the processing, out of the frame-shaped tube rows installed along the outer peripheral edge of the treated soil region, the tube row facing the adjacent contaminated soil treatment region is defined as the frame shape of the adjacent contaminated soil treatment region. Use as one side of the pipe row to remove the pipe row installed in the contaminated soil treatment area surrounded by the frame pipe row of the treated soil area, while the frame pipe row of the treated soil area is not When facing the treatment area, a DC current is passed through the frame-shaped tube rows and a DC voltage is applied to the electrodes, thereby causing electroosmosis into the soil between the electrodes of the frame-shaped tube rows. Treatment of contaminated soil characterized by causing a phenomenon and forming a water-impervious layer Law. 3. The method for treating contaminated earth according to claim 1, wherein when the polarity of the anode and the cathode is changed, washing water is passed through the upper end opening into the anode tube after the change, and both electrodes are DC-connected. A current is applied, a DC current is applied to both electrodes, a DC voltage is applied, and an electroosmosis phenomenon is caused in the contaminated soil between both electrodes, and the cathode is connected to the cathode through the water hole. A method for treating contaminated earth, which is characterized by preventing clogging of water passage holes in the anode tube by discharging cleaning water in the tube direction.

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