JP2001129529A - Method for cleaning contaminated ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cleaning a contaminated ground by which a cleaning promoting component can be spread across a broad area to reach a faraway distance and thereby the cleaning power of the contaminated ground can be significantly upgraded and the component, especially costly decomposition microbes are recovered as much as possible even in an unsaturated zone and thus their recycling are feasible. SOLUTION: This method for cleaning a contaminated ground comprises a cleaning promoting component injection process to intermittently inject the cleaning promoting component, in a pulsed state and at an interval of short time, into a contaminated ground 12 under superhigh pressure from an injection well 14 inserted into an excavated well 13 formed by excavation in the contaminated ground 12, and a recovery/cleaning treating process to recover a gaseous substance by suction from the ground 12 through the well 13 and make the gaseous substance harmless by purifying treatment and discharge the harmless gaseous substance. These two processes are alternately repeated at every passage of specified time. In the recovery/cleaning treating process, the cleaning promoting component injected in the preceding cleaning promoting component injection process can be sucked back as much as possible. Thus it is possible to recover the decomposition microbes even in an unsaturated zone and recycle them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying a contaminated ground, and more particularly, to a method in which ultrahigh-pressure air is pulsed at short intervals from an injection well inserted into the contaminated ground and intermittently blown into the contaminated ground. In addition, the present invention relates to a method for purifying a contaminated ground in which gaseous substances are sucked and collected from the contaminated ground.

[0002]

2. Description of the Related Art Pollutants include various substances such as organochlorine compounds, oils, and other heavy metals.
Grounds and waste landfills contaminated with contaminants including organic decomposition components other than these contaminants have become a major problem.

For this reason, various methods and apparatuses for purifying the above contaminants have been proposed in recent years. In situ purification, which is particularly advantageous in terms of equipment and space, is often found.
In this in situ purification, there is a method (bioremediation) that utilizes indigenous decomposed microorganisms. In order to activate these decomposed microorganisms, nutrients such as air (oxygen) and nutrients are injected into the ground, In some cases, it has been proposed to replenish degrading microorganisms. For example, JP-A-10-216696 discloses a device for supplying oxygen to contaminated soil. This is to set up an injection well that reaches the groundwater under the contaminated soil, supply supersaturated water containing excess oxygen into the groundwater from the injection well, and turn the groundwater into an oxygen supersaturated state, and generate fine bubbles from this oxygen supersaturated groundwater. To supply oxygen to contaminated soil on the surface.

[0004]

However, when oxygen is supplied to contaminated soil from such conventional groundwater, indigenous decomposing microorganisms are activated by the natural infiltration of oxygen into the soil. However, it requires a very long purification period, and the soil has cracks and soft spots, which are not uniform. Can not be purified.

It has also been considered that an injection well is inserted into contaminated soil, and oxygen (air) or other decomposition promoting substances and purification promoting components such as decomposition microorganisms themselves are directly injected into the soil. In this case, the purification-promoting component is injected into the soil in the form of an aqueous solution or gas, but even in this case, the purification is uneven due to the unevenness of the soil. In addition, at the time of injection, the injection pressure is maintained at a constant level. However, since the injection is performed continuously, it is difficult to set the injection pressure at a high pressure. Therefore, it is not possible to secure a wide purifiable area per injection well. Therefore, in order to purify the contaminated ground in a wide range of desired areas, the number of injection wells must be increased, and the cost of ground purification becomes high.

[0006] In particular, when the soil of the contaminated ground is in an unsaturated zone and there is no groundwater for dispersing decomposed microorganisms and other purification accelerating components into the ground, there is almost no movement of decomposed microorganisms and other decontamination accelerating components. Since this does not occur, the purifiable area is further reduced. Also, when degrading microorganisms are injected into such an unsaturated zone from an injection well,
Since the movement of the degrading microorganisms cannot be expected, it cannot be recovered together with the groundwater, so that the degrading microorganisms cannot be reused, and it is necessary to continuously inject new degrading microorganisms, and Since microorganisms are expensive, there is a problem that the cost of ground purification significantly rises.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to make it possible to make a purification-promoting component farther and more widely, thereby greatly improving the purification ability of contaminated ground. Another object of the present invention is to provide a method for purifying contaminated ground, which makes it possible to recover and reuse a purification promoting component, particularly an expensive decomposed microorganism, as much as possible even in an unsaturated zone.

[0008]

In order to achieve the above object, a method for purifying a contaminated ground according to the present invention comprises the steps of forming a purification promoting component into a pulsed form at a short time interval at an extremely high pressure in a drilling well drilled in the contaminated ground. A purification-promoting component injecting step into the surrounding contaminated ground from the drilling well, and a gaseous substance in the ground being sucked and recovered from the drilling well. A recovery and purification treatment step of detoxifying and discharging the substance by a purification treatment, wherein the purification promoting component injection step and the recovery and purification treatment step are alternately repeated (claim 1).

[0009] In this purification method, the drilling well in the step of injecting the purification-promoting component contains an ultra-high pressure (for example, 2 to 2).
10 atm) and supplied intermittently (for example, at a period of 1/30 to 1/5 HZ) at a short time interval, so that the purification promoting component is supplied from the drilling well into the contaminated ground in a predetermined manner. It will be explosively blown at ultra-high pressure with intermittent timing. For this reason, the purification promoting component injected into the contaminated ground from the drilling well is diffused and reaches a farther and wider area, and the contaminants in the contaminated ground are purified over a wide area, and 1 It is possible to greatly expand the purification area per injection well. In addition, since the explosive injection of the purification-promoting component is intermittently repeated in the form of a pulse, the path of the purification-promoting component is likely to be random at each injection, and the path of the purification-promoting component is likely to be random. The whole can be purified as uniformly as possible. Further, by intermittently injecting a purification promoting component suitable for mixed contaminants and the like, the concentration of the injected component can be easily controlled and waste can be eliminated.

[0010] In addition, from the drilling well in the recovery and purification treatment step, decomposition gas generated at the time of soil purification, surplus gas when a purification promoting component is injected in the form of gas (mist) from the injection well, and soil The moisture and the like in the interior are sucked. For this reason,
Even in soils in unsaturated zones, it is possible to recover as much as possible the purification-promoting components injected together with the gaseous substances in the purification-promoting-component injection process in the preceding process. By using this, the ground purification cost can be reduced as much as possible.

In addition, when switching between the purification promoting component injection step and the recovery / purification treatment step, it is only necessary to change the injection well and the suction means between the drilling wells in different adjacent steps, and the process can be easily shifted. It can be performed and has excellent workability.

Here, it is preferable that a plurality of the drilling wells are provided, and a drilling well adjacent to the drilling well in the purification promoting component injection step is a recovery and purification treatment step (claim 2).

According to this purification method, while the purification promoting component is injected into the contaminated ground from the drilling well in the purification promoting component injection step, the gaseous substance is sucked from the drilling well in the recovery purification processing step adjacent to the surrounding area. Before the harmful gaseous substances such as decomposed gas and surplus gas are naturally released from the ground to the atmosphere, these substances are collected and purified by a suction well, and the purification promoting components are more easily diffused. Since it can be released later, air pollution can be prevented as much as possible.

Further, as the above-mentioned purification promoting component, a component which promotes the purification of pollutants such as oxygen-containing substances such as air, hydrogen peroxide and ozone, decomposing microorganisms, and nutrients for activating the decomposing microorganisms is used. Thus, it is possible to appropriately perform purification in accordance with various pollutants (claim 3).

Further, a porous pipe is arranged on the inner periphery of the drilling well, and in the step of injecting the purification promoting component, the porous pipe has a spout at a tip and a spout at an upper side of the spout. Inserting an injection well fitted with a packer that seals tightly to the porous tube, and intermittently supplies the purification promoting component from the jet port. It is desirable to connect a recovery and purification treatment facility equipped with a suction means to suction and recover gaseous substances (claim 4).

In this purification method, since the injection position of the purification promoting component in one drilling well can be adjusted by changing the position up and down, even if the depth of the contaminated region of the contaminated ground is large, the purification promoting component can be adjusted up and down. In this case, the ground can be evenly blown in the direction, so that the purification of the ground can be equalized in the vertical direction. Further, when performing the process transition between the purification promoting component injecting step and the recovery and purification processing step, the work of replacing the recovery and purification processing equipment with the injection well and the suction means can be easily performed, and the workability in the process transition is excellent.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of a method for purifying contaminated ground according to the present invention, and FIG. 1 is a sectional view schematically showing a main part of a purification apparatus.

The basis of the method for purifying a contaminated ground according to the present invention is based on the fact that a purification promoting component is intermittently supplied at short intervals to a drilling well 13 formed in a contaminated ground 12 at an extremely high pressure. A step of injecting a purification-promoting component explosively from the drilling well 13 into the surrounding contaminated ground 12 at a high pressure at a predetermined intermittent timing; The present invention has a recovery and purification treatment step of recovering and detoxifying and recovering the collected gaseous substances by a purification treatment, and the purification promotion component injection step and the recovery and purification treatment step are alternately repeated.

That is, the method for purifying contaminated ground of the present invention is shown in FIG.
Can be achieved by the purifying apparatus 10 shown in FIG. This purification apparatus 10 shows one embodiment for achieving the purification method of the present invention, and is formed by digging a substantially vertical hole in the contaminated ground 12, and a porous tube 30 for earth retaining is inserted into the inner peripheral portion. Drilling well 13
And an injection well 14 inserted into the drilling well 13, and an ultrahigh-pressure compressed air attached to the upper end of the injection well 14 is pulsed at short intervals to intermittently fill the injection well 1.
4, a high-pressure intermittent injection device 16 for supplying to the compressed air, a purification-promoting component supply facility 20 connected to the compressed air supply path 18 for adding the purification-promoting component to the compressed air, and a drilling well 13 A recovery / purification treatment facility 40 including a suction pump 34 connected to the upper end of the porous tube 30 via a coupling or the like is provided.

The porous tube 30 is a pipe having an infinite number of openings formed by slits, holes, and the like formed on a peripheral surface of the porous tube 30 from a lower end to an upper portion over a predetermined length. It is inserted into the contaminant diffusion layer S in the ground 12, reaches a predetermined depth of the contaminated ground 12, and its upper end protrudes from the surface of the ground.

The injection well 1 inserted into the drilling well 13
4 is formed of a pipe having a predetermined length shorter than the porous pipe 30, and an ejection port 14 a provided at a lower end thereof is located at a predetermined depth of the contaminated ground 12, and the injection well 14 a
Is in a state protruding further above the upper end of the porous tube 30.

The high-pressure intermittent injection device 16 is connected to the injection well 1
4 is connected via a coupling to the high-pressure intermittent injection device 16, and compressed air of an ultra-high pressure (for example, 2 to 10 atm) generated by an air compressor 22 is supplied to a supply pipe 18.
a. The high-pressure intermittent injection device 16 includes a tank (not shown) that stores compressed air, and an intermittent valve that intermittently discharges compressed air in the tank,
When the pressure in the tank exceeds a predetermined pressure, the intermittent valve opens instantaneously to discharge high-pressure air, and when the pressure in the tank decreases due to this discharge, the intermittent valve closes instantly. I have.

Therefore, while the compressed air is supplied from the air compressor 22, the high-pressure intermittent injection device 16 intermittently changes the high-pressure air in the tank into pulses at short intervals (for example, 1/30 to 1/30). The compressed air is supplied to the injection well 14. Then, the compressed air of the ultra-high pressure is instantaneously injected into the surrounding contaminated ground 12 through the porous pipe 30 of the drilling well 13 from the jet port 14a at the lower end of the injection well 14 at a predetermined intermittent timing.
At the time of this injection, the cavitation effect is exerted, and the compressed air is explosively blown out from the myriad of holes of the porous tube 30, and the blowing energy at this time becomes extremely large.

The above-mentioned purification promoting component supply equipment 20 includes:
A storage tank 24 for storing the purification promoting component is provided, and this storage tank 24 is connected to a pipe 24 through a flow control valve 26.
At a, it is connected to the supply path 18 on the discharge side of the high-pressure intermittent injection device 16. Here, the supply path 18 is a path for supplying compressed air from the air compressor 22 into the contaminated ground 12, and the supply pipe 18a connecting the air compressor 22 and the high-pressure intermittent injection device 16, and the high-pressure intermittent injection device. 1
6 itself further includes an injection well 14. And
By opening the flow control valve 26, the purification promoting component in the storage tank 24 is added to the compressed air, and the amount of addition is controlled by adjusting the opening of the flow control valve 26.

The purification accelerating components stored in the storage tank 24 are air, hydrogen peroxide (H ₂ O ₂ ), ozone (O ₃ )
It is a component that promotes purification of contaminants such as oxygen-containing substances such as oxygen-decomposing microorganisms M, nutrients for activating the decomposed microorganisms M, and the like. The contaminants include, in particular, organochlorine compounds, oils, solvents, and volatile substances.

The air promotes the activation of the aerobic microorganisms M by the oxygen contained therein, and H ₂ O ₂ has the effect of separating oil from the soil particles of the oil-contaminated soil by bubbles when generating oxygen, After decomposing into water and oxygen, no extra substances remain,
And it can be easily injected as a mist. O ₃ has better oxidation efficiency. As the nutrient source, nutrients suitable for growing the degrading microorganism M and components suitable for activating the degrading microorganism M are used. Examples of the nutrient include phosphorus, nitrogen, potash, silicon, and the like of living organisms. There are some major elements required to maintain the above and trace elements such as manganese which are mainly taken as salts other than carbon, hydrogen and oxygen.

As the decomposing microorganism M, a methane-utilizing bacterium which aerobically decomposes (oxidizes) TCE (trichloroethylene) is known. In this methane-utilizing bacterium, methane is used as a nutrient source. Other decomposing microorganisms M used for TCE decomposition include toluene-utilizing bacteria, phenol-utilizing bacteria, nitrifying bacteria, propane-oxidizing bacteria, and isopropylene-oxidizing bacteria. Used. It goes without saying that a nutrient source suitable for the decomposing microorganism M that purifies the contaminant is used for other contaminants in the contaminated ground 12 without being limited to the TCE.

Accordingly, the air compressor 22 of the purification device 10 is driven to supply compressed air to the high-pressure intermittent injection device 16, and this ultra-high pressure compressed air is supplied from the injection port 14 a of the injection well 14 to the hole of the drilling well 13. By opening the flow control valve 26 of the purification promoting component supply facility 20 when injecting into the surrounding contaminated ground 12 through the quality pipe 30, the purification promoting component in the storage tank 26 is contaminated together with the compressed air. It can be injected into the ground 12. Here, the compressed air containing oxygen is one of the purification-promoting components, and is hereinafter referred to as the purification-promoting component including the compressed air.

The purification-promoting component injected into the contaminated ground 12 is pulsed at short intervals at an ultra-high pressure by the high-pressure intermittent injection device 16 and supplied at a predetermined intermittent timing. Explosive blowing into the contaminated ground 12 through the myriad openings in the tube 30 will result in reaching farther and more extensively. In addition, since the explosive injection of the purification promoting component is intermittently repeated, the deposition condition of the contaminated ground 12 changes every time the injection is performed, so that the path of the purification promoting component tends to become random, and the contamination ground 12
The whole is almost uniformly purified. Further, the flow rate of the purification promoting component can be controlled by adjusting the opening degree of the flow control valve 26. However, by performing the injection of the purification promoting component suitable for the mixed pollutants by intermittent injection, the intermittent injection component can be controlled. The concentration can be easily managed and waste can be eliminated.

As described above, the purification-promoting component injected into the contaminated ground 12 is diffused over a wider area, so that the purifying area per injection well 14 per unit can be expanded, and the contaminated ground in a certain area can be reduced. To perform purification, the number of injection wells 14 in the entire purification apparatus 10 can be reduced. In other words, the purification promoting component activates the decomposing microorganisms M contained in the contaminated ground 12 in a wide range by oxygen and nutrients contained in the air,
Promotes decomposition of pollutants. Further, in using the degrading microorganism M, if the polluted object is an oil, a solvent, or a volatile substance whose purification period is lengthened, by selecting a purification promoting component suitable for each purification, These contaminants can be properly purified within a short period of time. Furthermore, when the amount of indigenous decomposed microorganisms M is small, it is desirable to include replenished decomposed microorganisms M as a purification promoting component.

The purifying apparatus 10 for achieving the purifying method of this embodiment is provided with a suction well 31 for sucking gaseous substances in the ground 12. The suction well 31 is formed by the drilling well 13, and is configured by connecting a recovery and purification treatment facility 40 having a suction pump 34 to the upper end of the porous tube 30 of the drilling well 13 via a coupling. . The recovery and purification equipment 40 comprises a gas-liquid separator 32, a suction pump 34, an exhaust gas purification device 36, and a purified gas exhaust equipment 38.
And the high-pressure intermittent injection device 16 are appropriately replaced and connected to the porous pipe 30 of the drilling well 13. Each of the drilling wells 13 includes the injection well 14 and the suction well 3.
As shown in FIGS. 2A and 2B, each drilling well 13 alternately repeats a purification promoting component injection step and a recovery purification treatment step. Is performed. Further, the suction well 1 which is connected to the recovery / purification processing equipment 40 and performs the recovery / purification processing step.
4 and a plurality of injection wells 14 to which the high-pressure intermittent injection device 16 is connected to perform the purification promotion processing step, which are not shown, are arranged so as to surround each other in plan view, and adjacent ones are mutually connected. An injection well 14 and a suction well 14 of different processes are provided.

By operating the suction pump 34, the decomposition gas generated during soil purification and the purification promoting component from the injection well 14 are formed into a gas (mist) from the opening of the suction well 31. Excess gas and water in the soil at the time of injection are sucked. The gaseous substance mixed with water sucked in the suction well 31 in this manner is supplied to the gas-liquid separator 3.
After the separation in step 2, only the gas is sucked into the suction pump 34. Then, the gas sucked by the suction pump 34 is sent to the exhaust gas purifying device 36, where the gas is purified and rendered harmless, and then released into the atmosphere from the purified gas exhaust system 38.

That is, while the purification promoting component is injected into the contaminated ground 12 from the drilling well 13 in the purification promoting component injection step into which the injection well 14 has been inserted, the recovery promoting purification equipment 40 is connected adjacent to the periphery thereof. Since the gaseous substance is sucked from the drilling well 13 in the recovery and purification treatment step, the purification promoting component is more easily diffused, and harmful gaseous substances such as decomposition gas and surplus gas are naturally discharged from the ground to the atmosphere. Before being released,
Since these can be collected and collected in the suction well 31 and then released, the air pollution can be prevented as much as possible.

By the way, in the purification method of the present embodiment, for each excavation well 13, a purification promotion component injection step of inserting the injection well 14 into the porous tube 30 and injecting the purification promotion component, The recovery and purification process step of purifying and discharging the gaseous substance sucked and recovered by connecting the recovery and purification processing facility 40 to the recovery purification process unit 40 is switched and repeated alternately every predetermined time. The switching of the process is performed by exchanging the injection well 14 with the recovery and purification treatment equipment between the adjacent drilling wells 13 having different processes. Therefore, the work for switching the process can be easily performed only by performing the replacement.

Therefore, in the purification method of this embodiment, the purification promoting component is injected into the contaminated ground 12 from the injection well 14 and is sucked from the absorption well 31. Therefore, the purification promoting component supplied from the injection well 14 by this suction. Are more easily diffused. Therefore, the high-pressure intermittent injection device 1
In combination with the explosive blowing of the purification-promoting component via 6, the purifiable area can be significantly expanded.

Further, since the decomposition gas and surplus gas in the contaminated ground 12 can be collected by the suction well 30 before being naturally released to the atmosphere, air pollution can be prevented. Therefore, in this embodiment, purification of the contaminated ground 12
Since the stabilization is performed within a short period of time, it is particularly useful for early use of the site and environmental conservation, and the surrounding environment can be considered.

Further, in each of the drilling wells 13, the purification promoting component injection step and the recovery purification processing step are switched every time a predetermined time elapses, and these steps are sequentially and alternately repeated. From the drilling well, the decomposition gas generated at the time of soil purification, the excess gas when the purification promoting component is injected in the form of gas (mist) from the injection well 14, and the moisture in the soil are collected by suction. In doing so
Even if the soil on the contaminated ground is in an unsaturated zone, the purification-promoting component injected in the purification-promoting-component injection process in the preceding process can be recovered together with gaseous substances as much as possible.
By collecting and reusing expensive decomposed microorganisms, ground purification costs can be reduced as much as possible. In addition,
The water separated by the gas-liquid separation device 32 is returned to the storage tank 24 by a return pipe 32a, and the decomposed microorganisms collected together with the water separated by the gas-liquid are returned to the storage tank.

Here, as shown in FIG. 2, in the purification method of this embodiment, the injection well 14 is connected to the porous pipe 30 of the drilling well 13.
The injection position of the purification-promoting component from the injection port 14a of the injection well 14 can be adjusted in the vertical direction. In other words, the injection well 14 has its spout 14a
In the state located at the deepest part of the porous tube, its upper end protrudes above the upper end of the porous tube, and the high-pressure intermittent injection device 16 is attached to the protruded upper end. Then, a packer 42 is attached to the outer periphery of the injection well 14 above the jet port 14a, and the packer 42 is slidably brought into close contact with the inner circumference of the porous tube 30 to be injected from the jet port 14a. The purification promoting component is prevented from escaping upward, and can be concentrated and blown into the contaminated ground 12. More preferably, although not shown in the drawings, the ejection port 1
By providing a packer that moves up and down integrally with the injection well 14 and slidably seals the inside of the porous tube 30 below 4a, the concentration of the purification promoting component to be injected can be further improved. The porous pipe 30 may have a configuration in which a plurality of slits are vertically extended along a pipe length direction in a circumferential direction,
Such a slit tube is also included.

Therefore, in this embodiment, the injection port 14a can be moved up and down by moving up and down the injection well 14, so that the injection position of the purification promoting component can be changed up and down in one injection well 14. Therefore, even when the depth of the contaminated area of the contaminated ground 12 is large, the purification promoting component is blown evenly in the vertical direction, so that the purification of the ground 12 can be equalized in the vertical direction. Therefore, since the purification area in one injection well 14 is further expanded, the number of injection wells 14 in the entire purification apparatus 10b can be further reduced. Further, in this embodiment, it is desirable to change the position of the suction well 30 depending on the position of the jet port 14a.

[0040]

As described above, according to the method for purifying contaminated ground according to the first aspect of the present invention, the excavation well in the step of injecting the purification promoting component has an ultrahigh pressure (for example, 2 to 1).
0 atm) and pulsed at short time intervals and intermittently supplied (eg 1/30 to 1 / 5HZ cycle),
The purification promoting component is explosively blown from the drilling well into the contaminated ground at an extremely high pressure at a predetermined intermittent timing. For this reason, the purification promoting component injected into the contaminated ground from the drilling well is diffused and reaches a farther and wider area, and the contaminants in the contaminated ground are purified over a wide area, and 1 It is possible to greatly expand the purification area per injection well. In addition, since the explosive injection of the purification-promoting component is intermittently repeated in the form of a pulse, the path of the purification-promoting component is likely to be random at each injection, and the path of the purification-promoting component is likely to be random. The whole can be purified as uniformly as possible. Further, by intermittently injecting a purification promoting component suitable for mixed contaminants and the like, the concentration of the injected component can be easily controlled and waste can be eliminated.

Further, from the drilling well in the recovery and purification treatment step, the decomposition gas generated at the time of soil purification, the surplus gas when the purification promoting component is injected in the form of gas (mist) from the injection well, and the soil Because the water and the like in the inside are sucked, even in the soil in the unsaturated zone, the purification promoting component injected in the purification promoting component injection process in the preceding process can be recovered as much as possible together with the gaseous substances, In particular, by collecting and reusing expensive decomposed microorganisms, the cost of ground purification can be reduced as much as possible.

In addition, when switching between the purification promoting component injection step and the recovery purification treatment step, it is only necessary to replace the injection well and the suction means between the drilling wells in different adjacent steps, and the process can be easily shifted. It can be performed and has excellent workability.

According to the purification method of the present invention, while the purification promoting component is injected into the contaminated ground from the drilling well in the purification promoting component injection step, the gaseous substance is removed from the drilling well in the recovery and purification processing step adjacent thereto. As the purification promoting components are more easily diffused, harmful gaseous substances such as decomposition gas and surplus gas are collected by the suction well before they are naturally released from the ground to the atmosphere. Since it can be released after purification treatment, air pollution can be prevented as much as possible.

In the purification method according to the third aspect, the purification-promoting component is used to purify contaminants such as oxygen-containing substances such as air, hydrogen peroxide and ozone, decomposing microorganisms, and nutrient sources for activating the decomposing microorganisms. By using a promoting component,
Purification suitable for various pollutants can be performed properly.

According to a fourth aspect of the present invention, a porous pipe is disposed on the inner periphery of the drilling well, and in the step of injecting the purification promoting component, the porous pipe has a spout at a tip thereof. An injection well equipped with a packer that seals closely to the porous tube is inserted above the jet port to intermittently supply the purification accelerating component from the jet port. The suction means is connected to the upper end of the porous pipe to suction and collect gaseous substances. Therefore, the injection position of the purification promoting component in one drilling well can be adjusted by changing the position up and down, thereby contaminating the contaminated ground. Even when the depth of the region is large, the purification promoting component is evenly blown in the vertical direction, so that the purification of the ground can be equalized in the vertical direction. Further, when performing the process transition between the purification promoting component injecting step and the recovery and purification processing step, the work of replacing the recovery and purification processing equipment with the injection well and the suction means can be easily performed, and the workability in the process transition is excellent.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views schematically showing a main part of one embodiment of the present invention, wherein FIGS. 2A and 2B show before and after the process transition between a purification promoting component injection step and a recovery purification treatment step. It shows the status.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Purification apparatus 12 Contaminated ground 13 Drilling well 14 Injection well 14a Spout port 16 High-pressure intermittent injection apparatus 18 Supply path 20 Purification promoting component supply equipment 30 Porous pipe 31 Suction well 32 Gas-liquid separator 34 Suction pump 36 Exhaust gas purification apparatus 38 Purified gas exhaust equipment 40 Recovery and purification processing equipment 42 Packer

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirokazu Tsuji 4-640 Shimoseito, Kiyose-shi, Tokyo F-term in Obayashi Corporation Technical Research Institute Co., Ltd. (Reference) 2E191 BA11 BB01 BC01 BC05 BD11 BD20 4D004 AA41 AC07 CA18 CA36 CC01 CC02 CC07 CC15

Claims (4)

[Claims] 1. A purification promoting component is intermittently supplied to a drilling well drilled in a contaminated ground at an ultra-high pressure in the form of pulses at short intervals and intermittently supplied from the drilling well into the surrounding contaminated ground. A purifying accelerating component injecting step, and a collecting and purifying step of sucking and collecting gaseous substances in the ground from the drilling well, detoxifying and discharging the collected gaseous substances by a purifying treatment, and A method for purifying contaminated ground, characterized by alternately repeating the accelerating component injection step and the recovery / purification processing step. 2. The method for purifying contaminated ground according to claim 1, wherein a plurality of the drilling wells are provided, and a drilling well adjacent to the drilling well in the purification promoting component injection step is a recovery processing step. 3. The purification-promoting component is a component that promotes the purification of contaminants such as oxygen-containing substances such as air, hydrogen peroxide and ozone, decomposing microorganisms, and nutrient sources for activating decomposing microorganisms. The method for purifying contaminated ground according to claim 1, wherein: 4. A porous pipe is arranged on an inner periphery of the drilling well,
In the purification promoting component injection step, an injection well having a spout at the tip and having a packer tightly sealed to the porous pipe is inserted above the spout inside the porous tube, While intermittently supplying the purification-promoting component from the jet port, in the recovery-purification processing step, a suction-recovery processing facility equipped with a suction means is connected to the upper end of the porous tube to suction-recover gaseous substances. Claims 1 to
3. The method for purifying contaminated ground according to any one of 3.