WO2019198254A1

WO2019198254A1 - Method for purifying contaminated ground

Info

Publication number: WO2019198254A1
Application number: PCT/JP2018/024273
Authority: WO
Inventors: 須美夫山本
Original assignee: 株式会社沙羅
Priority date: 2018-04-11
Filing date: 2018-06-27
Publication date: 2019-10-17

Abstract

The purpose of the invention is to provide a method for purifying contaminated ground that can sufficiently vaporize VOCs in the ground, can promote a reaction between the vaporized VOCs and ozone, and, as a consequence, can effectively purify contaminated soil. A high-temperature vapor containing alkali made by dissolving an alkali compound into high-temperature water vapor at a high first temperature is injected into the ground via through-holes penetrating a drill pipe 3 inserted into the ground. An ozone-containing gas that includes ozone as a composition gas is supplied to a plurality of drill pipes 5 inserted into the ground away from the drill pipe 3 so as to surround the drill pipe 3, and the ozone-containing gas is injected into the ground via through-holes penetrating the drill pipes 5.

Description

Purification method for contaminated ground

The present invention relates to a method for purifying contaminated ground, and in particular, high-temperature alkali-containing water vapor in which an alkali compound is dissolved in moisture in the ground of the contaminated area through a borehole penetrating into the ground of the contaminated area, The present invention relates to a method for purifying contaminated ground in which an ozone-containing gas containing ozone is injected as a composition gas.

In the conventional method for purifying contaminated ground shown in Patent Document 1, the land contaminated by a pollutant mainly composed of volatile organic compounds (hereinafter referred to as “VOCs”) such as trichlorethylene and tetrachloroethylene. The ozone-containing gas and water are alternately injected into the ground through the borehole that has penetrated into the ground, and the alkaline liquid is supplied at a predetermined time zone at the end of the time zone during which water is injected. At the same time, the contaminated ground is purified by injecting it into the ground.

JP 2008-272575 A

However, in the conventional purification method of contaminated ground, although the factor that hinders the promotion of the reaction between ozone in the ozone-containing gas and VOCs can be removed to some extent by the injection of alkaline liquid, the ozone injected into the ground VOCs could not be sufficiently vaporized because the temperatures of the contained gas, water and alkaline liquid were not high, and the reaction between ozone in the ozone-containing gas and VOCs could not be promoted. As a result, the contaminated ground could not be effectively purified.

The present invention has been made in order to solve such problems, and can sufficiently vaporize VOCs in the ground and promote the reaction between the vaporized VOCs and ozone. It aims at providing the purification method of the contaminated ground which can purify effectively.

In order to achieve this object, the method for purifying contaminated ground according to the present invention is characterized in that alkali-containing water vapor obtained by dissolving an alkali compound in water of high-temperature water vapor having a high temperature at a first temperature is An alkali-containing water vapor injection step for injecting into the ground through an injection hole drilled in a direction intersecting the longitudinal direction of the first borehole penetrating into the first borehole, and a position spaced from the first borehole And supplying the ozone-containing gas containing ozone as a composition gas to a plurality of second boreholes penetrating into the ground so as to surround the first borehole, the second borehole pipe And an ozone-containing gas injection step of injecting the ozone-containing gas into the ground through an injection hole formed in a direction intersecting the longitudinal direction.

The method for purifying contaminated ground according to the invention described in claim 2 is characterized in that, in the method for purifying contaminated ground according to claim 1, the first temperature is a temperature of 200 ° C. or higher and 300 ° C. or lower. To do.

The method for purifying contaminated ground according to the invention described in claim 3 is the method for purifying contaminated ground according to claim 1 or 2, wherein the ozone-containing gas injection step is performed before the alkali-containing water vapor injection step. Alternatively, both processes are started at the same time.

The method for purifying contaminated ground according to the invention described in claim 4 is the method for purifying contaminated ground according to any one of claims 1 to 3, wherein the alkali-containing water vapor is an infinite number of alkali compounds. The small piece is exposed to the high-temperature water vapor, and is produced by dissolving the alkali compound in the water of the high-temperature water vapor.

The method for purifying contaminated ground according to the invention described in claim 5 is the method for purifying contaminated ground according to claim 4, wherein the alkali-containing water vapor is an infinite number of alkali compounds filled in the first borehole. The body is formed by being exposed to the high temperature steam supplied to the first borehole and dissolving the alkali compound in the water of the high temperature steam.

The method for purifying contaminated ground according to the invention described in claim 6 is the method for purifying contaminated ground according to claim 5, wherein the semi-high temperature steam having a second temperature lower than the first temperature is the first temperature. The high-temperature steam is generated by being supplied into the borehole and heated by a heating device disposed in the first borehole.

The method for purifying contaminated ground according to the invention described in claim 7 is the method for purifying contaminated ground according to claim 6, wherein the second temperature is a temperature not lower than 100 ° C and lower than 200 ° C. To do.

The method for purifying contaminated ground according to the invention described in claim 8 is the method for purifying contaminated ground according to any one of claims 1 to 7, wherein the alkali-containing steam injection step and the ozone-containing gas are used. After the injection step is completed, the ozone-containing gas is supplied to the first borehole, and the ozone-containing gas is injected into the ground through the injection hole of the first borehole. A gas injection step is further provided.

The method for purifying contaminated ground according to the invention described in claim 9 is the method for purifying contaminated ground according to claim 8, wherein, in the additional ozone-containing gas injection step, a third temperature lower than the first temperature. Is supplied to the first borehole together with the ozone-containing gas, and the quasi-high temperature steam and the ozone-containing gas are injected into the ground through the injection hole of the first borehole. It is characterized by doing so.

According to invention of Claim 1, the 2nd borehole which inject | pours ozone-containing gas through an injection hole in the position spaced apart from the 1st borehole which inject | pours high temperature alkali-containing water vapor | steam through an injection hole Is inserted into the ground, so that the high temperature alkali-containing water vapor injected into the ground through the injection hole of the first borehole reaches the vicinity of the second borehole before reaching the vicinity of the second borehole. The temperature when it reaches the vicinity of the second borehole is lower than the temperature immediately after being injected into the ground from the injection hole of the first borehole, by vaporizing . For this reason, even if hot alkali-containing water vapor is injected into the ground through the injection hole of the first borehole, the ozone-containing gas injected into the ground through the injection hole of the second borehole Ozone is not decomposed into oxygen in a short time by the heat of the alkali-containing water vapor that reaches the vicinity of the second borehole from the first borehole.

In addition, by supplying high temperature alkali-containing water vapor to the first borehole, the water vapor injected into the ground through the injection hole of the first borehole reaches the vicinity of the second borehole. Has a high temperature state, the vaporization of underground VOCs and mineral oil is promoted by the heat of the high temperature alkali-containing water vapor. The vaporized VOCs and mineral oil are conveyed by alkali-containing water vapor and reach the vicinity of the second borehole in a gas state with a relatively low temperature, so that the reached VOCs and mineral oil are contained in the ozone-containing gas. Reacts actively with ozone.

Also, it contains ozone in the ground through a plurality of second borehole injection holes that are spaced from the first borehole and that surround the first borehole. Since the gas is injected, the vaporized VOCs and mineral oil that are to diffuse toward the outside of the periphery of the first borehole are reliably purified by reacting with ozone in the ozone-containing gas.
Moreover, since alkali-containing water vapor | steam is inject | poured in the ground through the injection hole of a 1st borehole, alkali-containing water vapor | steam reaches | attains the 2nd borehole vicinity with VOCs of a gaseous state. For this reason, chlorine and hydrochloric acid produced by oxidative decomposition of VOCs with ozone are neutralized with alkali compounds contained in the alkali-containing water vapor to become harmless stable compounds. As a result, the decomposition of ozone by chlorine or hydrochloric acid can be effectively suppressed, and ozone can be prevented from being lost unnecessarily.

According to the invention of claim 2, since the first temperature is a temperature of 200 ° C. or more and 300 ° C. or less, the alkali-containing water vapor injected into the ground through the injection hole of the first borehole is Since there is a high temperature state before reaching the vicinity of the second borehole, vaporization of underground VOCs is promoted by the heat of the high temperature alkali-containing water vapor.
According to the invention described in claim 3, since the ozone-containing gas injection step is started prior to the alkali-containing water vapor injection step or both steps are simultaneously started, the ground is introduced through the injection hole of the first borehole. Until the alkali-containing water vapor injected therein reaches the vicinity of the second borehole, a sufficient amount of ozone-containing gas necessary for purification can be secured in the vicinity of the second borehole.

According to the invention of claim 4, the alkali-containing water vapor is generated by exposing countless small pieces of the alkali compound to the high-temperature water vapor and dissolving the alkali compound in the water of the high-temperature water vapor. Water vapor can be easily generated.
According to the invention of claim 5, the alkali-containing water vapor is obtained by exposing the countless small pieces of the alkali compound filled in the first borehole to the high-temperature water vapor supplied to the first borehole. Since it is generated by dissolving an alkali compound in the moisture of water vapor, an apparatus for producing alkali-containing water vapor can be configured with a simple structure.

According to the invention described in claim 6, since the high temperature steam is generated by heating the semi-high temperature steam by the heating device disposed in the first borehole, the high temperature steam just generated is Immediately, it can be injected into the ground through the injection hole of the first borehole. For this reason, underground VOCs and mineral oil can be effectively vaporized by the heat of water vapor in a high temperature state.

According to the invention described in claim 7, since the second temperature is a temperature not lower than 100 ° C. and lower than 200 ° C., the apparatus for generating the quasi-high temperature steam has an extremely large steam heating capability. There is no need to prepare.

According to the invention described in claim 8, after the alkali-containing water vapor injection step and the ozone-containing gas injection step are completed, the ozone-containing gas is supplied to the first borehole, and the first borehole is injected through the injection hole. And an additional ozone-containing gas injection step for injecting the ozone-containing gas into the ground. For this reason, the mineral oil that remains in a liquid state without being vaporized by the mineral oil that existed in the ground between the first and second boreholes is not subjected to the alkali-containing steam injection step. When it is soaped by reacting with alkali compounds in the alkali-containing water vapor injected into the ground and remaining around the first borehole, the soaping is due to the implementation of an additional ozone-containing gas injection step. Promoted by ozone in ozone-containing gas.

According to the ninth aspect of the invention, in the additional ozone-containing gas injection step, the semi-high temperature steam having a third temperature lower than the first temperature is supplied to the first borehole along with the ozone-containing gas, The semi-hot water vapor and ozone-containing gas were injected into the ground through the injection hole of one borehole. For this reason, the mineral oil remaining in the liquid state without being vaporized by the mineral oil existing in the ground between the first and second boreholes is reliably heated by the quasi-high temperature steam. As a result, it is vigorously reacted with the alkali compound in the alkali-containing steam remaining after being injected into the ground to be soaped, and the soaping is promoted by ozone in the ozone-containing gas.

It is the figure which showed the state which looked at the ground of the pollution area | region where the several drill pipe penetrated in order to implement the purification method of the contaminated ground which concerns on embodiment of this invention. It is the figure which fractured | ruptured and showed the state where the various apparatuses used when implementing the purification method of the contaminated ground which concerns on embodiment of this invention were connected to the borehole. It is the figure which fractured | ruptured and showed the state where the various apparatuses used when implementing the purification method of the contaminated ground which concerns on embodiment of this invention were connected to the borehole. In order to implement the purification method of the contaminated ground according to the embodiment of the present invention for a partial region of the ground shown in FIG. 1, a state in which the ground on which various devices are installed is viewed from above is schematically shown. It is a figure. It is the figure which expanded and showed a part of the figure enclosed with the dashed-two dotted line in FIG.

The figure which fractured | ruptured and showed the state in which the electric heater and heat exchanger of the water vapor | steam heating apparatus used when implementing the purification method of the contaminated ground which concerns on embodiment of this invention were integrated It is. It is the figure which showed the thing before they are integrated with the electric heater and heat exchanger of the heating apparatus of the water vapor | steam shown in FIG. It is the figure which showed the state which looked at the ground where the some point to investigate was set from the upper direction in order to identify a contaminated area in implementing the purification method of the contaminated ground which concerns on embodiment of this invention. It is the figure which fractured | ruptured and showed the state where the various apparatuses used when implementing the operation | work which pinpoints the depth of contamination in the ground were connected to the borehole. In order to carry out the method for purifying contaminated ground according to the embodiment of the present invention, a state is shown in which a part of the contaminated area where a plurality of boreholes are penetrated into the ground as viewed from above the ground is increased. FIG.

Hereinafter, an example of a method for purifying contaminated ground according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 9. In addition, about drawing, the ratio of the reduced scale of each structural member may be shown mutually differing on account of drawing. FIG. 1 shows a state in which the ground of a place where a method for purifying contaminated ground is carried out is viewed from above. In FIG. 1, what is indicated by a symbol R is the underground M mainly due to contaminants composed of VOCs and mineral oil. The area including the area where the soil is contaminated is shown. In this region R, a plurality of small regions each having a substantially regular hexagonal shape having a certain length L1 (for example, 1 meter) on the ground are continuously set in a honeycomb shape in all directions on the ground without any gaps. ing. In FIG. 1, these small areas are set at 10 places (small areas R1 to R10) for the sake of simplicity.

The test tubes 3 are respectively connected to points O1 to O10 corresponding to the centers of the substantially regular hexagons in the small regions R1 to R10 to a predetermined depth (for example, 10 meters) in the ground M substantially parallel to each other. (Not shown). These boreholes 3 constitute the “first borehole” in the present invention.

On the other hand, at the six points A corresponding to the vertices of the substantially regular hexagons in the small regions R1 to R10, the predetermined depth is substantially parallel to the borehole 3 penetrating the points O1 to O10. The boreholes 5 are penetrated into the underground M to substantially the same depth or deeper than the predetermined depth. These boreholes 5 constitute a “second borehole” in the present invention.

In addition, the length L1 of one side of the substantially regular hexagonal shape described above is supplied to the test tube 3 at points O1 to O10 corresponding to the center of the substantially regular hexagonal shape by a steam supply device 9 and an ozone-containing gas supply device 11 described later. The water vapor and the ozone-containing gas are set to such a length that they can flow through the underground M and reach each borehole 5 at the point A corresponding to each vertex of the substantially regular hexagonal shape.

Each borehole 3 and each borehole 5 are, for example, long ones formed by connecting a plurality of short steel or stainless steel boreholes having an outer diameter and an inner diameter of 34 millimeters and 25 millimeters and a length of 1 to 2 meters, respectively. The borehole 3 and the borehole 5 are configured. When the length of the borehole 3 or the borehole 5 is insufficient as it penetrates into the underground M, the borehole 3 or the borehole 5 is penetrated into the underground M while connecting and connecting the boreholes. Go. As the configuration to be connected, the short bore pipes in which the male screw portion and the female screw portion are respectively engraved at both ends of the short bore tube, the male screw portion of one borehole and the female screw portion of the other borehole Are connected to each other.

As shown in FIG. 2 and FIG. 3, an excavation member 7 for excavating the underground M and drilling a hole in the ground E is screwed to the female threaded portion at the tip of each of the

test tubes

3 and 5. ing. Each borehole 3 is provided with a through hole 3a in a direction intersecting the longitudinal direction, and each borehole 5 is provided with a through hole 5a in a direction intersecting the longitudinal direction. The shape of the through hole 3a and the through hole 5a is formed in an elliptical shape, a slit shape, or a circular shape that is long in the longitudinal direction of the test tube 3 and the test tube 5. The size of the through hole 3a is smaller than the small piece 27 so that an alkali compound small piece 27 described later does not pass therethrough. Examples of the diameter when the through hole 3a is circular include 2.5 to 4.5 millimeters. The shape and size of the through hole 5a may be formed in the same manner as the through hole 3a or may be different.
A plurality of through-holes 3 a are drilled in the vicinity of the drilling member 7 on the side surface of the short borehole to which the drilling member 7 is screwed, of the shortest drilling tubes constituting each drilling tube 3. A plurality of through-holes 5 a are formed in the vicinity of the excavation member 7 on the side surface of the short borehole to which the excavation member 7 is screwed.

The through-hole 3a constitutes the “first borehole injection hole” in the present invention, and the through-hole 5a constitutes the “second borehole injection hole” in the present invention. The through-hole 3a and the four through-holes 5a are each formed in four directions around the axis at intervals of 90 degrees when viewed from the direction along the axis of the short bore tube. In the present embodiment, each test bore short tube of the test tube 3 and each test tube short tube of the test tube 5 are made of the same material, size and structure, and the test tube 3 and the test tube 5 are the same. However, the present invention is not limited to this, and the borehole 3 and the borehole 5 may be made of different materials, dimensions, and structures.

Next, an apparatus for carrying out the “alkali-containing steam injection process”, which is one process in the work process of the contaminated ground purification method, will be described with reference to FIGS. 1 to 7. Among the boreholes 3 penetrating the points O1 to O10, each of the boreholes 3 penetrating the points O1, O3, O8, and O10 is connected to the water vapor supply device 9 and the ozone-containing gas supply device 11 to form a small region. The ozone-containing gas supply device 11 is connected to each borehole 5 penetrating at six points A ... corresponding to the vertices of the substantially regular hexagonal shapes in R1, R3, R8, and R10. In FIG. 4, for the convenience of drawing, only the portions related to the small regions R1 to R3 in the small regions R1 to R10 shown in FIG. 1 are shown.

The lower end of a cylindrical connecting tube 15 (see FIGS. 2 and 5) is screwed to the upper end of each borehole 3. Female threaded portions 15 a and 15 b are respectively carved on the inner peripheral surfaces of the upper and lower portions of the connecting pipes 15. The female threaded portions 15 a of the lower portions of the connecting pipes 15 are formed on the outer peripheral portion of the upper end portion of each borehole 3. The formed male screw portions 3b are screwed in an airtight manner. Male threaded parts 17a carved on the outer peripheral surface of the lower part of the cylindrical nipple 17 are screwed into the female threaded parts 15b at the upper part of each connection pipe 15, respectively. Female threaded portions 21 a carved on the inner peripheral surface of the lower part of the cylindrical joint 21 are screwed to the male threaded portions 17 b carved on the outer peripheral surface of the upper part of each nipple 17.

A male screw portion 23a engraved on the outer peripheral surface of one end portion of the water vapor branch pipe 23 is screwed to the female screw portion 21b engraved on the inner peripheral surface of the upper end portion of each joint 21. The other end of the steam branch pipe 23 is connected to the middle part in the longitudinal direction of the steam collecting pipe 25, and the steam collecting pipe 25 is connected to the steam supply device 9. The high-temperature steam generated by the steam supply device 9 passes through the steam collecting pipe 25, the steam branch pipe 23, the joint 21, the nipple 17 and the connecting pipe 15 in this order, and is supplied to each borehole pipe 3.

In addition, the lower end portion in each borehole 3 is filled with countless small pieces 27 of an alkali compound (see the figure shown in FIG. 2 by enlarging the portion surrounded by the dashed-dotted ellipse in FIG. 2). A heating device 29 is disposed above each region in each of the test tubes 3 filled with the countless small pieces 27... With a certain gap in the vertical direction. Examples of the alkali compound include potassium hydroxide and sodium hydroxide. Examples of the shape of the single small piece 27 include a granular shape, a spherical shape, a tablet shape, a bead shape, and a flake shape. The size of the single small piece 27 is such that high-temperature steam after heating can pass smoothly through countless small pieces 27... And the alkali-containing steam is efficiently generated by being exposed to the high-temperature steam. Is desirable. For this reason, when the small piece body 27 is granular, spherical, tablet-like or bead-like, it is desirable that the dimension corresponding to the outer diameter is 5 to 6 millimeters. In the case of a flake shape, if the shape is a square, the length of one side is preferably 5 to 6 millimeters.

The other end of each of the pair of

electric wires

31, 31 each having one end connected to the upper end of the heating device 29 extends to the outside through a communication hole 15 c drilled in the middle in the longitudinal direction of the connection pipe 15. Each of the extended other end portions is electrically connected to a control device 33 a in the control panel 33. In the pair of

electric wires

31, 31, a seal member 34 is attached to an outer peripheral portion of a portion inserted through the communication hole 15 c of the connection pipe 15, and the gap between the pair of

electric wires

31, 31 and the seal member 34 is set. The space between the seal member 34 and the communication hole 15c is hermetically sealed.

Each of the joints 21 has a female threaded portion 21c formed in a through hole formed in a side portion in the middle in the longitudinal direction. The female threaded portion 21c is formed at one end of the ozone-containing gas branch pipe 35. The male screw portions 35a are screwed in an airtight manner. The other end of each ozone-containing gas branch pipe 35 is connected to a first collecting pipe 37a, and the first collecting pipe 37a is connected to the ozone-containing gas main pipe 38 connected to the ozone-containing gas supply device 11 with a first electromagnetic wave. It is connected via a type open / close valve 39. The ozone-containing gas generated by the ozone-containing gas supply device 11 is generated by switching the first electromagnetic on-off valve 39 so that the ozone-containing gas main pipe 38 communicates with the second collecting pipe 37a. The pipe 38, the first electromagnetic open / close valve 39, the first collecting pipe 37a, the ozone-containing gas branch pipe 35, the joint 21, the nipple 17 and the connecting pipe 15 are passed through these in this order and are supplied to the boreholes 3 respectively.

Of the small regions R1 to R10, male screw portions 5b (in FIG. 3) formed on the outer peripheral portion of the upper end portion of each borehole 5 that penetrates into the respective six points A in the small regions R1, R3, R8, R10. In the enlarged view of the part surrounded by the dashed-dotted ellipse, see the figure shown in the figure), the female threaded portion 45a engraved on the lower inner peripheral surface of the cylindrical connecting tube 45 is screwed in an airtight manner. Has been. Male threaded portions 47a formed at one end of the ozone-containing gas branch tube 47 are screwed in an airtight manner to female threaded portions 45b carved on the inner peripheral surface of the upper end portion of each connecting tube 45.

The other end of each ozone-containing gas branch pipe 47 is connected to a second collecting pipe 37b, and the second collecting pipe 37b is connected to the ozone-containing gas main pipe 38 via the first electromagnetic on-off valve 39. Yes. A second electromagnetic switching valve 49 is disposed in the middle in the longitudinal direction of each ozone-containing gas branch pipe 47. A female threaded portion 45c is engraved in each of the through-holes drilled in the side portion in the longitudinal direction of each connecting tube 45. The female threaded portion 45c has a male threaded portion formed at one end of the gas sampling tube 51. 51a is screwed in an airtight manner. Connected to the other end of the gas sampling tube 51 is a connector 53 to which a concentration measuring device (not shown) for measuring the concentration of gas sampled from the underground M through the borehole 5 is connected.

The ozone-containing gas generated by the ozone-containing gas supply device 11 is changed to the ozone-containing gas main pipe by switching the first electromagnetic on-off valve 39 so that the ozone-containing gas main pipe 38 communicates with the second collecting pipe 37b. 38, the first electromagnetic open / close valve 39, the second collecting pipe 37b, the ozone-containing gas branch pipe 47, and the connecting pipe 45 are respectively supplied to the boreholes 5 through the order.

The water vapor supply device 9 includes a boiler 9a constituting the main body and a pressure adjusting device 9b disposed on the upper portion of the boiler 9a, and a water vapor collecting pipe 25 is connected to the pressure adjusting device 9b. The pressure adjusting device 9b has a function of adjusting the pressure of the steam supplied from the boiler 9a to the steam collecting pipe 25 to be constant. There is a correlation between the pressure of water vapor and the temperature. When the pressure is determined, the temperature is also determined according to the pressure. For example, the temperature when the water vapor pressure is 0.3 MPa (megapascal) is about 134 ° C. The temperature of the water vapor supplied to the water vapor collecting pipe 25 is adjusted by adjusting the pressure of the water vapor by the pressure adjusting device 9b.

Specifically, the pressure adjusting device 9b is controlled by the control device 33a so that the temperature of the water vapor becomes a predetermined temperature in a range of 100 ° C. or higher and lower than 200 ° C. For this reason, it is not necessary to prepare an apparatus for generating steam that has an extremely large steam heating capability. The predetermined temperature in the range of 100 ° C. or higher and lower than 200 ° C. constitutes the “second temperature” in the present invention. As this predetermined temperature, the temperature of 150 degreeC can be mentioned, for example.

As shown in FIGS. 6 and 7, the heating device 29 is connected to one end of each electric wire 31, and a columnar electric heater 61 that generates heat when current flows through each electric wire 31, and the electric heater 61 includes And a heat exchanger 63 to be inserted.
The heat exchanger 63 includes a cylindrical heat radiating pipe 65 and a belt-shaped heat radiating fin 67 that is wound around and bound to the outer periphery of the heat radiating pipe 65 in a spiral shape. Between the outer peripheral surface of the electric heater 61 inserted into the heat radiating tube 65 and the inner peripheral surface of the heat radiating tube 65, an adhesive 69 having a good thermal conductivity (a portion surrounded by an ellipse indicated by a two-dot chain line in FIG. 6). (See the diagram shown in the same figure), and the electric heater 61 and the heat exchanger 63 are thereby integrated. By arranging the heating device 29 in the borehole 3, a spiral path is formed by the heat exchanger 63 of the heating device 29 and the inner peripheral surface of the borehole 3.

As shown in FIGS. 2 and 3, the ozone-containing gas supply device 11 is connected to an oxygen cylinder 71 containing oxygen gas via an oxygen gas supply pipe 73, and the oxygen gas in the oxygen cylinder 71 is ozone. It is introduced into the contained gas supply device 11. Ozone is generated by silent discharge by the discharge tube inside the ozone-containing gas supply device 11, and ozone is mixed with oxygen at a predetermined ratio to generate ozone-containing gas. As an ozone-containing gas containing ozone as such a composition gas, for example, a gas in which ozone is 1 to 10 percent by volume and the remainder is oxygen can be mentioned. The ozone-containing gas thus generated is supplied from the ozone-containing gas supply device 11 to the ozone-containing gas main pipe 38 at a pressure of, for example, 0.8 to 1.1 MPa (megapascal).

The above-described electric drive devices of the pressure adjusting device 9b of the water vapor supply device 9, the ozone-containing gas supply device 11, the first electromagnetic on-off valve 39, and the second electromagnetic switching valve 49 should be appropriately controlled. These are electrically connected to a control device 33a in the control panel 33 via electric wires (not shown).

<Work process of purification method for contaminated ground>
Next, the work process of the contaminated ground purification method will be described with reference to FIGS.
(1) Identifying the contaminated area FIG. 8 shows a plurality of points B to be investigated in order to identify the contaminated area by investigating the land in which the soil in the ground M is contaminated by pollutants composed of VOCs and mineral oil. It shows the state when the ground where is set is viewed from above. The plurality of points B... Are set in an area that is estimated to be a contaminated area in consideration of a specific use for each area of the land to be investigated.

The plurality of points B... Thus set are set such that the distances between the adjacent points B are all set to the length L2 when the ground is viewed from above, and the points B are set in an aligned state. Yes. The length L2 may be the same length as L1, but may be a length different from L1. Needless to say, the smaller the length of L2, the better the accuracy of the contamination investigation. A method of investigating is that an iron or stainless steel gas sampling tube (not shown) made of a tube (for example, an outer diameter and an inner diameter of 14 mm and 9 mm, respectively) thinner than the test tube 3 and the test tube 5 is provided at each point B. After penetrating the underground M by a drilling device (not shown), gas is sampled through the gas sampling tube, and the concentration of the collected VOCs gas is measured by a concentration measuring device 79 described later. A drilling member for excavating the underground M and drilling a hole in the ground E is bound to the distal end portion of the gas sampling pipe, and a plurality of through holes are drilled on the side surface in the vicinity of the drilling member. ing. Gas is collected through these through holes. As the depth to the lower end of the gas sampling pipe penetrating into the ground M, for example, any depth of 0.5 to 2 meters (for example, 1 meter) can be mentioned.

By measuring the concentration of the VOCs gas collected from the underground M at each point B through the gas sampling pipe by the concentration measuring device 79 for each point B individually, the concentration of the VOCs gas at each point B is measured. The concentration can be known, and thereby the contaminated area of the ground can be specified two-dimensionally. If the measured value of the measured gas concentration is larger than a preset VOCs concentration determination value (a reference value that can be determined as not contaminated by VOCs), it is determined that the gas is contaminated. Judge as uncontaminated. A region S surrounded by an alternate long and short dash line in FIG. 8 indicates a planar region when the contaminated region determined to be contaminated is viewed from above, and a region R surrounded by a two-dot chain line wider than the region S. These are areas set based on the area S, and indicate areas from which purification work will be performed. The distance between the outer edge of the region S and the outer edge of the region R is set to 1 to 2 meters, for example.

(2) Identifying Depth of Contamination in the Ground After the contaminated area is specified two-dimensionally, next, a plurality of points that penetrate the borehole 3 and the borehole 5 are set in the area R. These plural points are set so as to be aligned, and are described as point A... And points O1 to O10 in FIG. The points A ... are points corresponding to the vertices of a substantially regular hexagon having one side of length L1, and the points O1 to O10 are points corresponding to the center of the substantially regular hexagon.

First, the boreholes 3 were inserted into the points O1 to O10 to the depths of 1 to 2 meters shallower than the depth at which the groundwater layer is assumed to exist, and then connected to the upper end of each borehole 3. Suction pump (not shown) is sucked through a gas sampling pipe (not shown), and the presence or absence of groundwater is investigated for each point O1 to O10. If the groundwater is not aspirated, it penetrates the borehole 3 slightly deeper, and then it is aspirated with a suction pump, and the presence of groundwater is investigated again. Repeat the further penetration of each borehole 3 and the investigation for the presence or absence of groundwater until the groundwater is aspirated. When the groundwater is aspirated, the borehole 3 is gradually lifted by the borehole device until the groundwater is not aspirated, and the lifting operation of the borehole 3 is completed at the depth when the groundwater is no longer aspirated. Leave tube 3 penetrating.

When the work of penetrating the boreholes 3 into the ground M at the points O1 to O10 is completed, six boreholes 5 surrounding each of the boreholes 3 at the points O1, O3, O8, and O10 are respectively formed by the borehole device. Intrude. The depth of penetration of each borehole 5 is the same as the depth of penetration of the borehole 3 surrounded by the borehole 5.

When the penetration of each borehole 3 and each borehole 5 into the underground M is completed, as shown in FIG. 9, the steam supply device 9 and the control panel 33 are connected via an electric wire (not shown), The steam supply device 9 is connected to the connection pipe 75 attached to the upper end portion of each borehole 3 that has penetrated into the points O1, O3, O8, and O10 via the steam branch pipe 23 and the steam collecting pipe 25. On the other hand, a concentration measuring device 79 is connected to a connecting pipe 77 attached to the upper end portion of each borehole 5 surrounding each borehole 3 inserted into the points O1, O3, O8, O10 via a gas sampling pipe 51 and a connector 53. Connect. The concentration measuring device 79 is for measuring the concentration of various gases.

Next, the control panel 33 is operated to supply the water vapor generated by the water vapor supply device 9 to each borehole 3 that has penetrated into the points O1, O3, O8, and O10. At this time, the pressure adjusting device 9b of the water vapor supply device 9 is controlled by the control device 33a so that the temperature of the water vapor supplied from the water vapor supply device 9 becomes a predetermined temperature in a range of 100 ° C. or higher and lower than 200 ° C. An example of the predetermined temperature is 150 ° C.

The quasi-high-temperature steam at the predetermined temperature is supplied into each borehole 3 and injected into the ground M through the through-hole 3a of the borehole 3, and VOCs in the ground M are vaporized by the heat of the injected steam. Is done. While injecting semi-high temperature steam into the underground M through each borehole 3, the gas of VOCs vaporized in the underground M is sucked and collected by the concentration measuring device 79 through each borehole 5 and the gas sampling pipe 51. Then, the concentration of the collected gas is measured by the concentration measuring device 79. If the measured value measured by the concentration measuring device 79 is less than or equal to the VOCs concentration determination value, the borehole 3 and the six boreholes 5 surrounding the borehole 3 are respectively the same amount from the ground M (set in advance). The gas concentration is again measured by the concentration measuring device 79.

Until the concentration of the gas sampled from at least one of the six boreholes 5 surrounding one borehole 3 exceeds the VOCs concentration determination value, the borehole 3 and the borehole 3 Repeat the further lifting of the six boreholes 5 surrounding and measuring the gas concentration. The test tube 3 and the test tube 5 are pulled up for each of the small regions R1, R3, R8, and R10 shown in FIG. When the measured value exceeds the VOCs concentration determination value, the borehole 3 and the 6 boreholes 5 surrounding the borehole 3 are left penetrating at that depth. As a result, the borehole 3 and the six boreholes 5 surrounding the borehole 3 are in a state of being penetrated at the same depth in the ground M.
In this way, for each of the boreholes 3 penetrating the points O1, O3, O8, and O10 and the six boreholes 5 surrounding each of the boreholes 3, the most of the contaminated area of the underground M Penetration work to a deep depth is completed.

(3) Preparatory work for the first-stage purification work Next, after removing the connecting pipe 75 attached to the upper end portion of each borehole 3, as shown in FIG. These innumerable small pieces 27 are filled and a heating device 29 is provided. The ozone-containing gas supply device 11 is connected to each borehole tube 3 through the ozone-containing gas branch pipe 35, the first collecting pipe 37a, and the ozone-containing gas main pipe 38, and the water vapor branch pipe 23 and the water vapor collecting pipe 25 are connected. The steam supply device 9 is connected to each of the boreholes 3, and each heating device 29 is connected to the control panel 33. Further, after removing the connecting pipe 77 attached to the upper end of each borehole 5, as shown in FIG. 3, the ozone-containing gas branch pipe 47, the second collecting pipe 37b, and the ozone-containing gas main pipe 38 are used. The ozone-containing gas supply device 11 is connected to each borehole 5.

(4) First-stage purification operation Next, the control panel 33 is operated to open all the second electromagnetic switching valves 49, and the ozone-containing gas main pipe 38 and the second collecting pipe 37b communicate with each other. After switching the first electromagnetic on-off valve 39, the ozone-containing gas produced by the ozone-containing gas supply device 11 is inserted into each borehole 5 penetrating into the small regions R1, R3, R8, R10 shown in FIG. Supply gas. Thereby, ozone containing gas is inject | poured into the underground M through the through-hole 5a of each borehole 5. FIG. This injection step constitutes the “ozone-containing gas injection step” in the present invention.

When a predetermined time (for example, 30 minutes to 1 hour) has elapsed since the start of the ozone-containing gas injection step, the control panel 33 is operated to supply power to the electric heater 61 of the heating device 29 and to be generated by the water vapor supply device 9 The drilled steam is passed through each of the boreholes 3 penetrating into the points O1, O3, O8, and O10 shown in FIG. 1 through the steam collecting pipe 25, the steam branching pipe 23, the joint 21, the nipple 17 and the connecting pipe 15. Supply to tube 3. At this time, the pressure adjusting device 9b of the water vapor supply device 9 is controlled by the control device 33a so that the temperature of the water vapor supplied from the water vapor supply device 9 becomes a predetermined temperature in a range of 100 ° C. or higher and lower than 200 ° C. The predetermined temperature constitutes the “second temperature” in the present invention. An example of the predetermined temperature is 150 ° C.

In this way, when the semi-high temperature steam at the predetermined temperature is supplied into each borehole 3 and passes through a portion in the borehole 3 in which the heating device 29 is inserted, the heat exchanger of the heating device 29 It passes through a spiral passage formed by 63 and the inner peripheral surface of the borehole 3 while turning. At this time, the steam is sufficiently heated by the electric heater 61 that is energized and heated to a high temperature, and high-temperature steam having a predetermined temperature in the range of 200 ° C. to 300 ° C. is generated. For this reason, the high temperature steam just generated can be immediately injected into the underground M through the through hole 3a of the borehole 3, and the VOCs and mineral oil in the underground M are effectively removed by the heat of the high temperature steam. Can be vaporized. The predetermined temperature in the range of 200 ° C. or higher and 300 ° C. or lower constitutes the “first temperature” in the present invention. An example of the predetermined temperature is 250 ° C. The amount of electric power supplied to the electric heater 61 of the heating device 29 is controlled by the control device 33a so as to reach such a predetermined temperature.

The high-temperature steam after heating passes between the countless small pieces 27 of the alkali compound filled in the lower end portion of the borehole 3 so that the countless small pieces 27 of the alkali compound become high-temperature steam. The alkali compound is dissolved in the moisture of the high-temperature steam by exposure, and as a result, alkali-containing steam is generated. For this reason, it is possible to easily generate alkali-containing water vapor and to configure an apparatus for generating alkali-containing water vapor with a simple structure. The generated alkali-containing water vapor is injected into the underground M through each through hole 3a of each borehole 3 in a high temperature state. This injection step constitutes the “alkali-containing water vapor injection step” in the present invention. Thereby, substantially all of the VOCs existing in the underground M near the borehole 3 are vaporized by the heat of the high-temperature alkali-containing water vapor, and part of the mineral oil compatible with the VOCs is also vaporized. As a result, the vaporized VOCs and mineral oil present in the underground M near the borehole 3 are diffused outward around the borehole 3 by the alkali-containing water vapor.

In this first stage purification operation, the ozone-containing gas injection step is started before the alkali-containing water vapor injection step. However, the present invention is not limited to this, and both steps may be started simultaneously. In any case, until the alkali-containing water vapor injected into the underground M through the through-hole 3a of the borehole 3 reaches the vicinity of the borehole 5, an ozone-containing gas in an amount necessary for purification is supplied to the borehole. 5 can be secured sufficiently in the vicinity of 5.

While carrying out an ozone-containing gas injection process for supplying ozone-containing gas to each of the boreholes 5 surrounding the borehole 3, the alkali-containing water vapor is supplied to the borehole 3 and injected into the underground M through the through hole 3a. Since the alkali-containing water vapor injection step is performed, the VOCs and mineral oil in the gaseous state that diffused toward the periphery of the borehole 3 and reached the vicinity of the borehole 5 are the through holes 5a of the boreholes 5a. The ozone effectively reacts with ozone in the ozone-containing gas injected into the underground M via the oxidization, and oxidative decomposition by ozone is actively performed. For this reason, substantially all of the VOCs existing around the borehole 3 are reliably purified in a short time, and part of the mineral oil (vaporized) compatible with the VOCs is also reliably purified.

When VOCs are oxidatively decomposed by ozone, chlorine and hydrochloric acid are generated. These chlorine and hydrochloric acid function as a catalyst for decomposing ozone. As a result, ozone is reduced and ozone necessary for purification is insufficient. is there. However, since the alkali-containing water vapor is injected into the ground M through the through-hole 3a of the borehole 3, the alkali-containing water vapor also reaches the vicinity of the borehole 5 together with the VOCs and mineral oil in the gas state. When the alkali compound contained in the alkali-containing water vapor is potassium hydroxide or sodium hydroxide, chlorine and hydrochloric acid generated by oxidative decomposition of VOCs with ozone are neutralized with the alkali compound and harmless sodium chloride and potassium chloride Is generated. For this reason, the decomposition | disassembly of ozone by chlorine or hydrochloric acid can be suppressed effectively, and it does not need to lose | eliminate ozone wastefully.

Moreover, the borehole 5 which inject | pours ozone-containing gas through each through-hole 5a is penetrated in the underground M in the position away from the borehole 3 which inject | pours high temperature alkali-containing water vapor | steam through each through-hole 3a. Therefore, the high-temperature alkali-containing water vapor injected into the underground M through the through-hole 3a of the borehole 3 vaporizes the VOCs and mineral oil in the underground M before reaching the vicinity of the borehole 5 or underground. By contacting the soil of M, the temperature when reaching the vicinity of the borehole 5 is lower than the temperature immediately after being injected into the ground M from the through hole 3a of the borehole 3. For this reason, even if hot alkali-containing water vapor is injected into the underground M through the through-holes 3a of the boreholes 3, the ozone-containing gas injected into the underground M through the through-holes 5a of the boreholes 5 The ozone inside is not decomposed into oxygen in a short time by the heat of the alkali-containing water vapor that has reached the vicinity of the borehole 5 from the borehole 3.

On the other hand, since the alkali-containing water vapor injected into the underground M through the through-hole 3a of the borehole 3 has a high temperature state before reaching the vicinity of the borehole 5, the heat of the hot alkali-containing water vapor is high. This promotes the vaporization of underground VOCs and mineral oil. The vaporized VOCs and mineral oil are transported by alkali-containing water vapor and reach the vicinity of the borehole 5 in a gas state with a relatively low temperature. Therefore, the VOCs and mineral oil that have reached in the gas state are contained in the ozone-containing gas. Reacts actively with ozone.

Further, the ozone-containing gas is injected into the underground M through the through-holes 5a of the plurality of boreholes 5 inserted at the position away from the borehole 3 and surrounding the borehole 3. Therefore, the vaporized VOCs and mineral oil that try to diffuse outward around the borehole 3 react with ozone in the ozone-containing gas and are reliably purified.
Further, the mineral oil remaining without being vaporized by the mineral oil existing around each borehole 3 becomes a high-temperature liquid state by the heat of the high-temperature alkali-containing water vapor, and the alkali compound in the alkali-containing water vapor As it reacts, it is oxidized and soaped by ozone in the ozone-containing gas.

When this first purification operation is performed for a predetermined time (for example, 5 to 6 hours), the control panel 33 is operated to supply the semi-high temperature steam by the steam supply device 9 and the ozone-containing gas by the ozone-containing gas supply device 11. The supply of electric power to the electric heater 61 of the supply and heating device 29 is temporarily stopped. Then, a concentration measuring device 79 is connected to each connector 53 connected to the connection pipe 45 of each borehole 5 via the gas sampling pipe 51, and the VOCs gas is sucked from the underground M via each borehole 5. Then, the concentration of the collected gas is measured.

If the measured value of the measured gas concentration is greater than the VOCs concentration determination value, the first-stage purification operation is continued until the measured value of the VOCs concentration is equal to or lower than the VOCs concentration determination value. At this time, the concentration of the gas sampled through some of the six boreholes 5 surrounding the borehole 3 is not more than the VOCs concentration determination value, but was taken through the remaining boreholes 5. When the gas concentration is larger than the VOCs concentration determination value, the supply of ozone-containing gas is continued to the remaining borehole 5 and the borehole 5 adjacent to the remaining borehole 5, while the other boreholes 5 (the gas concentration is equal to or lower than the VOCs concentration determination value) connected to the ozone-containing gas branch pipe 47, the second electromagnetic switching valve 49 is opened and closed to the borehole 5 Stop supply of contained gas. This is to avoid wasteful supply of the ozone-containing gas.

(5) Second-stage purification operation When the first-stage purification operation is completed, the control panel 33 is operated to cut off the energization of the heater 29 of the heating device 29 and the ozone-containing gas main pipe 38 is The first electromagnetic on-off valve 39 is switched so as to communicate with the one collecting pipe 37a. Thereby, the ozone containing gas produced | generated with the ozone containing gas supply apparatus 11 comes to be supplied to each borehole 3 of point O1, O3, O8, O10, and through the through-hole 3a of each borehole 3 Ozone-containing gas is injected into the underground M. This step of injecting the ozone-containing gas into each borehole 3 constitutes the “additional ozone-containing gas injection step” as referred to in the present invention. At this time, the semi-high temperature steam having a predetermined temperature generated by the steam supply device 9 is also supplied to each of the boreholes 3 at the points O1, O3, O8, and O10, and countless small pieces of alkali compounds in the boreholes 3 are obtained. 27... Passing through, the innumerable small pieces 27 of the alkali compound are exposed to the quasi-high temperature steam, and the alkali compound is dissolved in the water of the quasi-high temperature steam to generate alkali-containing steam. And this alkali-containing water vapor | steam is inject | poured into the underground M through the through-hole 3a of each borehole 3 with ozone-containing gas.

At this time, the pressure adjusting device 9b of the water vapor supply device 9 is controlled by the control device 33a so that the temperature of the water vapor supplied from the water vapor supply device 9 becomes a predetermined temperature in the range of 100 ° C. or higher and lower than 200 ° C. . The predetermined temperature constitutes a “third temperature” in the present invention. The predetermined temperature may be the same temperature (for example, 150 ° C.) as the predetermined temperature of the water vapor supplied to each borehole tube 3 in the first-stage purification operation or a different temperature.

Thus, ozone-containing gas and quasi-high-temperature steam are injected into the ground M through the through holes 3a of the boreholes 3 at the points O1, O3, O8, and O10. As a result, the mineral oil remaining in the liquid state without being vaporized or soaped by the mineral oil present around each borehole 3 in the purification operation of the first stage is the quasi Alkaline in the alkali-containing water vapor that is injected into the ground M in the first-stage purification operation and remains around each of the boreholes 3 by being heated to a high temperature liquid state by the high temperature water vapor. It is soaped by vigorously reacting with the compound and the alkali compound in the alkali-containing water vapor injected into the ground M in this second stage purification operation. This soaping is further promoted by ozone in the ozone-containing gas injected into the underground M in the second stage purification operation. The compound produced by soaping the mineral oil is water-soluble and dissolves in water to become a nutrient of microorganisms and to be biologically processed and purified.

In the first-stage purification operation, when the remaining heat remains sufficiently in the underground M due to high-temperature alkali-containing water vapor being injected into the underground M through the through-holes 3a of the boreholes 3. In this second stage purification operation, the semi-high temperature water vapor is not supplied to each borehole 3 and only the ozone-containing gas is injected into the underground M through the through-hole 3a of each borehole 3. May be. In that case, the mineral oil reacts with the alkali compound in the alkali-containing water vapor and the ozone in the ozone-containing gas in a liquid state with a relatively high temperature due to the residual heat remaining in the underground M, and is soaped. .

When this second stage purification operation is performed for a predetermined time (for example, 5 to 6 hours), the control panel 33 is operated to supply the semi-high temperature steam by the steam supply device 9 and the ozone-containing gas supply by the ozone-containing gas supply device 11. Stop supplying temporarily. The concentration measuring device 79 is connected to the connector 53 connected to the connecting pipe 45 of each borehole 5 via the gas sampling pipe 51, and the mineral oil gas is discharged from the underground M via the borehole 5. Collect by suction and measure the concentration of the collected gas.
If the measured value of the concentration of the gas sampled from at least one of the boreholes 5 is greater than the mineral oil concentration judgment value (a reference value that can be judged as not contaminated with mineral oil), the mineral oil concentration judgment This second stage of purification is continued until the value is below the value.

(6) First-stage purification work after depth change When the second-stage purification work described above is completed, each borehole 3 and each borehole 5 are moved upward by the same amount (a preset short amount). The depth of penetration of each borehole 3 and each borehole 5 with respect to the underground M is changed to another depth that has not yet undergone purification work.
After changing the depth in this way, the same operation as the above-described “(4) First-stage purification operation” is performed again.

(7) Second-stage purification work after depth change After the "(6) First-stage purification work after depth change" is completed, the control panel 33 is operated to connect the heating device 29 to the electric heater 61. The first electromagnetic on-off valve 39 is switched so that the energization is interrupted and the ozone-containing gas main pipe 38 and the first collecting pipe 37a communicate with each other, and the same as the above-mentioned “(5) Second stage purification operation”. Perform the above procedure again.

(8) Remediation operations in first stage and second stage after re-depth change “(6) First-stage purification work after depth change” and “(7) Second-stage purification after depth change” The “operation” is performed until the purification is completed for all the depths in which the contaminated areas are specified in the small areas R1, R3, R8, and R10, and when the purification is completed for all the depths, the small areas R1, R3, R8, and R10 are performed. The purification work in is completed.

(9) Purification work for other contaminated areas Next, the boreholes 5 are connected to all the points A that surround the points O2, O4, O7, and O9 and are not penetrated by the borehole device. Intrude. Thereby, each borehole 3 penetrated into the points O2, O4, O7, and O9 is surrounded by six boreholes 5, respectively. The depth of penetration of the six boreholes 5 is the same as the depth of penetration of the borehole 3 surrounded by the six boreholes 5. Therefore, when the depth of the borehole 5 already penetrated in the previous purification operation is different from the depth of the borehole 3 surrounded by the borehole 5, the borehole is matched with the depth of the borehole 3. Re-penetrate tube 5.

Next, innumerable small pieces 27 of the alkaline compound are filled in each of the test tubes 3 at the points O2, O4, O7, and O9, and are attached to the test tubes 3 at the points O1, O3, O8, and O10, respectively. The connecting pipes 15, the nipples 17, the joints 21, and the heating devices 29 are removed and reattached to the test tubes 3 at the points O 2, O 4, O 7, and O 9, and the steam supply devices 9 are connected to the test tubes 3. Then, the piping is performed again so that the water vapor generated in step 1 and the ozone-containing gas generated in the ozone-containing gas supply device 11 are supplied.

Further, of the boreholes 5 in the small regions R1, R3, R8, and R10, the connecting tube 45 and ozone attached to the boreholes 5 included in any one of the small regions R2, R4, R7, and R9. The contained gas branch pipe 47 and the like are left attached to the borehole 5, while the connecting pipe 45 and the ozone-containing gas branch pipe attached to each of the boreholes 5 in the small regions R 1, R 3, R 8, and R 10 other than them. 47 and the like are removed and reattached to each of the test tubes 5 in the small regions R2, R4, R7, and R9 where the connecting pipe 45 and the ozone-containing gas branch pipe 47 are not attached. Thereby, the ozone containing gas produced | generated with the ozone containing gas supply apparatus 11 is supplied to each borehole 5 of small area | region R2, R4, R7, R9.
Next, the control panel 33 is operated to perform the operations from “(4) First-stage purification work” to “(8) First-stage and second-stage purification work after re-depth change” described above. The same operation is performed for each borehole 3 and each borehole 5 in the small regions R2, R4, R7, and R9.

(10) Cleaning operation of remaining contaminated area After the cleaning work in the small areas R2, R4, R7, and R9 is completed, the same operation as the “(9) Cleaning operation of other contaminated areas” is performed on the remaining contaminated areas. It carries out about a certain small region R5, R6. When the purification operations in the small regions R5 and R6 are completed, all the purification operations in the region R are completed.

The area around the small areas R5 and R6 (the small areas R1 to R4, R7 to R10) was purified before the small areas R5 and R6. The water vapor injected through the borehole 3 and the borehole 5 This is because VOCs and mineral oil existing outside the small regions R5 and R6 in the vicinity of the outer periphery of the small regions R5 and R6 are prevented from diffusing outward from the small regions R5 and R6 by the ozone-containing gas. That is, by purifying the regions around the small regions R5 and R6 (small regions R1 to R4, R7 to R10) first, when performing the purification operation of the small regions R5 and R6, the regions outside the small regions R5 and R6 are outside. Since VOCs and mineral oil do not exist in the direction, VOCs and mineral oil do not diffuse outward from the small regions R5 and R6.

The embodiment of the present invention described above is an example for explaining the present invention, and the present invention is not limited to the above-described embodiment, and the invention can be read from the whole of the claims and the specification. The method of purifying the contaminated ground after such change is also included in the technical scope of the present invention.

For example, in the above-described embodiment, an example of a method for purifying contaminated ground that purifies both VOCs and mineral oil contaminants has been shown. However, only one contaminant of VOCs or mineral oil exists in the underground M. Even in this case, it goes without saying that the pollutant in the underground M can be purified by carrying out the method for purifying contaminated ground according to the present invention.
Further, in the embodiment described above, an example in which the small areas are set to 10 locations R1 to R10 is shown for the sake of simplicity. However, the number of small areas is that the soil is contaminated with VOCs or mineral oil. It is set according to the area of the region R.

Further, in the purification method for contaminated ground according to the above-described embodiment, the small regions R1, R3, R8, and R10 are simultaneously purified, then the small regions R2, R4, R7, and R9 are simultaneously purified, and finally the small region R5. , R6 are purified at the same time. However, the present invention is not limited to this, and each small region may be purified by shifting the time sequentially one by one.

Moreover, in the purification method of the contaminated ground of embodiment mentioned above, while making each small area | region R1 thru | or R10 into the small area which consists of a substantially regular hexagon shape, six points A corresponding to each vertex of a substantially regular hexagon shape. Although the borehole 5 is penetrated into ..., the number of boreholes 5 to be penetrated is further increased by 6 for each small region, and the number of boreholes 5 penetrating around one borehole 3 is determined. A total of 12 may be used. FIG. 10 shows only the small region R1. In addition to the six boreholes 5 penetrating at the points A in the small region R1, six boreholes 5 are further penetrated at the points C. , A state in which the ground into which a total of twelve boreholes 5 are inserted is viewed from above. These points C are positioned at points corresponding to the vertices of a substantially regular hexagonal shape indicated by a one-dot chain line in FIG. By injecting ozone-containing gas into the underground M through the through-holes 5a of these twelve boreholes 5, vaporized VOCs that are to diffuse toward the outer periphery of the borehole 3 are converted into each borehole 5. The ozone-containing gas supplied to the gas is reliably purified without leakage.

3 borehole (first borehole)
3a Through hole (injection hole of the first borehole)
5 borehole (second borehole)
5a Through hole (injection hole of second borehole)
27 Small piece of alkali compound 29 Heating device M Underground

Claims

The alkali-containing water vapor obtained by dissolving the alkali compound in the water of the high-temperature water vapor having a high first temperature is in a high temperature state in a direction intersecting the longitudinal direction of the first borehole penetrating into the ground. An alkali-containing water vapor injection step for injecting into the ground through the injection hole formed;
An ozone-containing gas containing ozone as a composition gas is placed in a plurality of second boreholes that are spaced from the first borehole and penetrated into the ground so as to surround the first borehole. And supplying an ozone-containing gas injection step for injecting the ozone-containing gas into the ground through an injection hole formed in the second borehole in a direction intersecting the longitudinal direction thereof. Purification method.
In the purification method of the contaminated ground of Claim 1,
Said 1st temperature is the temperature of 200 to 300 degreeC, The purification method of the contaminated ground characterized by the above-mentioned.
In the purification method of the contaminated ground of Claim 1 or Claim 2,
The method for purifying contaminated ground, wherein the ozone-containing gas injection step is started prior to the alkali-containing water vapor injection step or both steps are started simultaneously.
In the purification method of the contaminated ground as described in any one of Claims 1 thru | or 3,
The method for purifying contaminated ground, wherein the alkali-containing water vapor is produced by exposing countless small pieces of an alkali compound to the high-temperature water vapor and dissolving the alkali compound in the water of the high-temperature water vapor.
In the purification method of the contaminated ground according to claim 4,
The alkali-containing water vapor is obtained by exposing the countless small pieces of the alkali compound filled in the first borehole to the high-temperature water vapor supplied to the first borehole tube, so that the alkali A method for purifying contaminated ground, wherein the compound is produced by dissolving a compound.
In the purification method of the contaminated ground according to claim 5,
The semi-high temperature steam having a second temperature lower than the first temperature is supplied into the first borehole and heated by a heating device disposed in the first borehole, so that the hot steam is A method for purifying contaminated ground, characterized by being produced.
In the purification method of the polluted ground of Claim 6,
Said 2nd temperature is the temperature of 100 degreeC or more and less than 200 degreeC, The purification method of the contaminated ground characterized by the above-mentioned.
In the purification method of the polluted ground as described in any one of Claims 1 thru | or 7,
After the alkali-containing water vapor injection step and the ozone-containing gas injection step are completed, the ozone-containing gas is supplied to the first borehole, and the underground through the injection hole of the first borehole A method for purifying contaminated ground, further comprising an additional ozone-containing gas injection step of injecting the ozone-containing gas.
In the purification method of the contaminated ground according to claim 8,
In the additional ozone-containing gas injection step,
Supplying quasi-high-temperature water vapor having a third temperature lower than the first temperature to the first borehole along with the ozone-containing gas, and through the injection hole of the first borehole to the ground A method for purifying contaminated ground, characterized in that semi-high temperature steam and the ozone-containing gas are injected.