JP4136388B2 - Contaminated soil purification method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for purifying contaminated soil, and more particularly, to a technique for decomposing substances contaminating soil by the biochemical action of aerobic microorganisms that inhabit the ground.
[0002]
[Prior art]
The site of the factory and the land where industrial waste has been illegally dumped are contaminated with heavy oil, volatile organic compounds, and other various pollutants, and the soil must be purified.
If it is a contaminated area near the surface of the earth, it is easy to dispose of the contaminated soil, treat it, etc., but if a deep area in the ground is contaminated, the treatment is very difficult.
[0003]
Here, if the aerobic microorganisms that inhabit the ground are activated, it is possible to decompose pollutants present in deep regions.
In order to activate aerobic microorganisms to degrade pollutants, air must be supplied over the entire area where the aerobic microorganisms are to be activated.
[0004]
However, it is very difficult to supply air over a deep region in the ground, and therefore, purification of contaminated soil using aerobic microorganisms has not yet been put into practical use.
[0005]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-described problems of the prior art, and effectively removes soil that exists in a deep underground region and is contaminated with contaminants by the biochemical action of aerobic microorganisms in the ground. It aims to provide a contaminated soil purification method that can be decomposed and purified.
[0006]
[Means for Solving the Problems]
As a result of various studies, the inventor has paid attention to the fact that air bubbles having a diameter of several μm to 10 μm can pass through the ground.
[0007]
According to the present invention, in a contaminated soil purification method for decomposing substances contaminating soil by biochemical action of aerobic microorganisms that inhabit the ground, a large number of silica pipes 20 are arranged with epoxy resin spacers. The buried conduit 12 was prepared and installed in the ground below the contaminated soil region C to be purified so that the silica pipe 20 of the conduit 12 corresponds to the contaminated soil region C, and the gas was dissolved in the conduit 12. The liquid is allowed to flow, and bubbles having a diameter of about several μm to 10 μm are generated by cavitation at the outlet of the silica pipe 12.
[0008]
In addition, according to the present invention, in the contaminated soil purification method for decomposing substances contaminating the soil by the biochemical action of aerobic microorganisms that live in the ground, a large number of silica pipes 20 are arranged with epoxy resin spacers. The conduit 12 buried in this way is prepared and installed in the ground below the contaminated soil region C to be purified so that the silica pipe 20 of the conduit 12 corresponds to the contaminated soil region C. A liquid containing bubbles is allowed to flow, and the bubbles are subdivided by a shearing force at the outlet orifice of the silica pipe 20 to generate bubbles having a diameter of several μm to 10 μm.
[0009]
The silica pipe is formed as a microtubule having an inner diameter of 9 μm or less by so-called “nanotechnology”. A relatively low-viscosity fluid, water, or the like flows through a silica pipe having an inner diameter of about 9 μm.
[0010]
For example, when the liquid is water, when water in which air is dissolved or water containing fine bubbles flows through a silica pipe, the air and water are separated inside the silica pipe, and the air is fine from the silica pipe. It comes out in the form of bubbles.
[0011]
If water is dissolved water, the air dissolved in the water when it comes out of the silica pipe becomes bubbles having a diameter of about several μm to 10 μm due to cavitation.
On the other hand, in the case of water containing fine bubbles, the fine bubbles are subdivided by shearing force at the exit orifice of the silica pipe and become bubbles having a diameter of about several μm to 10 μm when exiting the silica pipe.
Bubbles having a diameter (or particle size) of several μm to 10 μm rise in the ground, reach the contaminated soil region, and activate aerobic microorganisms that inhabit the region. The pollutants are decomposed by biochemical action resulting from the activation of aerobic microorganisms in the ground, and the contaminated soil is purified.
[0013]
Here, when the water pressure in the conduit is increased and water with a high gas solubility is passed through a small hole in the silica pipe, a large amount of cavitation bubbles are generated at the exit of the silica pipe. It will occur and you will not be able to pass through the ground.
On the other hand, if the water pressure in the conduit is too low, water cannot sufficiently flow through the silica pipe having high flow resistance, and cavitation bubbles cannot be formed.
Therefore, the water pressure is preferably about earth pressure plus 5 to 10 atmospheres.
[0014]
In addition, if the interval between the adjacent silica pipes is narrow, the generated bubbles come into contact with each other at the silica pipe outlet, and the diameter becomes larger than about several μm to 10 μm, so that they cannot pass through the ground. .
In order to prevent such a situation, the interval between adjacent silica pipes needs to be at least three times (27 μm or more) the inner diameter of the silica pipe.
[0015]
Thus, in order to set the interval between adjacent silica pipes to 3 times or more (27 μm or more) of the inner diameter of the silica pipe, it is necessary to form a spacer, for example, with an epoxy resin or the like in a region between adjacent silica pipes. is there. In addition, what is necessary is just to apply the existing technique, in order to arrange | position many silica pipes via a spacer.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing an overall configuration for carrying out the purification method of the present invention on contaminated soil existing deep in the ground and contaminated with pollutants.
[0017]
In FIG. 1, a conduit 12 is installed in a substantially horizontal direction in the ground immediately below the region C of the contaminated soil to be purified deep in the ground, and there are a large number of regions 12S corresponding to the contaminated soil in the conduit 12 in the region 12S. Silica pipe 20 is embedded.
And in the inside of the conduit 12, water in which air is dissolved (water having a high degree of dissolved gas), or water containing fine bubbles (water in which air is dissolved and water containing fine bubbles are: Both of which are denoted by reference numeral “10”), and are configured to flow out into the soil through the silica pipe 20.
[0018]
Here, when water containing fine bubbles flows through the inside of the conduit 12, the particle size of the fine bubbles is about 50 to 100 μm, and the content is about 10% or less in terms of gas volume ratio.
[0019]
FIG. 2 is an enlarged view of a main part of the conduit 12 indicated by reference numeral F2 in FIG. A large number of silica pipes 20 embedded in the conduit 12 each have an inner diameter dimension D of 9 μm or less, and a distance P between adjacent pipes is not less than three times the inner diameter D (27 μm or more). An epoxy resin spacer 30 is provided between the pipes 20 and 20, and the pipes are supported by being separated from each other.
The conduit 12 is provided with a head by means not shown so that the water pressure inside the conduit 12 becomes earth pressure plus about 5 to 10 atm.
[0020]
According to the configuration described above, the water in which the air flowing through the conduit 12 below the contaminated soil region C is dissolved (water having a high gas solubility) is the outlet of the silica pipe 12 having an inner diameter D of 9 μm or less. A large amount of cavitation bubbles are generated.
Such cavitation bubbles are discharged into the ground as fine bubbles mB having a diameter of about several μm to 10 μm (for example, a diameter of about 9 μm).
[0021]
Alternatively, if the water flowing through the conduit 12 includes water containing fine bubbles, the outlet orifice effect of the silica pipe 12 results in fine bubbles mB having a diameter of several μm to 10 μm (for example, a diameter of about 9 μm), Released into the ground.
[0022]
At that time, since each silica pipe 12 is 3D or more apart from each other, the bubbles mB do not come into contact with each other and rise in the soil while maintaining a diameter of about several μm to 10 μm. Area C is reached.
Fine bubbles mB (having a diameter of several μm to 10 μm) that reach the contaminated soil region C activate aerobic microorganisms that inhabit the contaminated soil region C. As a result, the pollutants in the contaminated soil region C are decomposed by the biochemical action of aerobic microorganisms, and the soil is purified.
[0023]
It should be noted that the illustrated embodiments are merely examples, and are not intended to limit the technical scope of the present invention.
[0024]
【The invention's effect】
The present invention is configured as described above, and effectively decomposes and purifies soil that exists in a deep underground region and is contaminated with contaminants by the biochemical action of underground aerobic microorganisms. It becomes possible to do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the entire ground for carrying out a purification method according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of a conduit used in the purification method of the present invention.
[Explanation of symbols]
C: Contaminated soil area mB: Fine bubbles 12: Conduit 12S through which water containing dissolved water or water containing fine bubbles flows ... Silica pipe of the conduit 20 ..Silica pipe 30 ... Spacer D ... Inner diameter dimension P of silica pipe ... Space between adjacent silica pipes

Claims (2)

  In a contaminated soil remediation method that decomposes substances that contaminate the soil by the biochemical action of aerobic microorganisms that inhabit the ground, a conduit embedded with a large number of silica pipes (20) arranged with epoxy resin spacers ( 12) is prepared and installed in the ground below the contaminated soil region (C) to be purified so that the silica pipe (20) of the conduit (12) corresponds to the contaminated soil region (C). (12) A method for purifying contaminated soil, wherein a liquid in which a gas is dissolved is allowed to flow, and bubbles having a diameter of several μm to 10 μm are generated by cavitation at the outlet of the silica pipe (12).   In a contaminated soil remediation method that decomposes substances that contaminate the soil by the biochemical action of aerobic microorganisms that inhabit the ground, a conduit embedded with a large number of silica pipes (20) arranged with epoxy resin spacers ( 12) is prepared and installed in the ground below the contaminated soil region (C) to be purified so that the silica pipe (20) of the conduit (12) corresponds to the contaminated soil region (C). (12) A polluted soil characterized by causing a liquid containing fine bubbles to flow through and being subdivided by a shearing force at an outlet orifice of a silica pipe (20) to generate bubbles having a diameter of several μm to 10 μm. Purification method.

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