JP3709780B2 - Pollutant decomposition system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pollutant decomposition system for detoxifying various harmful substances such as oil and organic chlorine compounds contained in contaminated soil, industrial waste, sludge, and the like by bioremediation.
[0002]
[Prior art]
When foundation work is carried out at a factory site, fuel oil and machine oil may be mixed with excavated soil. Moreover, the situation where oil flows out by some accident and the surrounding ground is contaminated with the oil is also assumed.
[0003]
If such contaminated soil is left as it is, the oil contained in the soil will volatilize and diffuse to the surroundings, hindering the lives of the local residents, and if it is released from the soil particles by rainwater, It may also cause contamination of the water quality. Therefore, for soil contaminated with oil, it is necessary to remove the oil by, for example, incineration to prevent diffusion to the environment.
[0004]
In addition, the soil in the factory site may contain organic chlorine compounds such as carcinogenic substances such as trichlorethylene and tetrachloroethylene. If such soil is left as it is, the organic chlorine compounds will still pass through groundwater. May spread to the environment, and as with oil-contaminated soil, a predetermined purification process must be performed.
[0005]
On the other hand, research on bioremediation, a technology for degrading and detoxifying environmental pollutants using the activity of microorganisms, has recently been advanced, and it can also be applied to soil contaminated with oil, organochlorine compounds, etc. It has come to be studied.
[0006]
Bioremediation is a method of degrading and detoxifying pollutants using the ability of microorganisms such as bacteria and fungi to break down. By adjusting to an environment such as aeration to improve the activity of microorganisms, it is possible to decompose pollutants more efficiently than in the natural state.
[0007]
[Problems to be solved by the invention]
A certain result has been confirmed at the laboratory level for such a pollutant treatment method using microorganisms, and a realistic response is highly expected in the future.
[0008]
However, when working to stir with the addition of nutrients and moisture to promote decomposing bacteria and their growth to contaminated soil, or when processing by subsequent bioremediation, such as oil and organochlorine compounds There has been a problem that harmful substances are scattered in the atmosphere and may cause bad odor.
[0009]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a pollutant decomposition system that can perform bioremediation without generating malodor.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the method for decomposing a pollutant according to the present invention comprises performing bioremediation on a pollutant containing a pollutant such as oil or an organic chlorine compound as described in claim 1. In the pollutant decomposition system for decomposing and removing the pollutants,
An air suction pipe is arranged in communication with the contaminant spread on a predetermined work surface, and a suction pump and a deodorizing device are connected in series with each other at the tip of the air suction pipe. The air suction pipe is laid in a state surrounded by clogging prevention materials such as gravel in the groove.
[0013]
In the pollutant decomposition system according to the present invention, first, an air suction pipe is arranged so that the contaminant containing the contaminant is spread on a predetermined work surface and communicated with the contaminant. After that, the suction pump connected to the tip of the air suction pipe is operated to extract the air in the pollutant, and the air is deodorized by the deodorizing device connected to the outlet side of the suction pump and then released to the atmosphere. . Alternatively, the suction pump disposed downstream is operated to draw out the air in the pollutants, and the air is passed through a deodorizing device installed between the air suction pipe and the suction pump to be deodorized and released to the atmosphere. .
[0014]
In this way, contaminants such as oil and organochlorine compounds themselves, intermediate products generated in the process of bioremediation, and other odor-causing substances are sucked together with air through a suction pump with a suction pump. At the same time, it is released to the atmosphere after being deodorized and removed by the deodorizing device, and there is no possibility that the substance causing the bad odor will be scattered or diffused around the pollutant.
[0015]
Moreover, since the surrounding fresh air is taken in in a contaminant by air suction, the inside of a contaminant is maintained in an aerobic environment. Therefore, the activity of a degrading bacterium which is an aerobic bacterium is increased, and the degradation of pollutants is promoted.
[0016]
As microorganisms used for bioremediation, indigenous bacteria such as bacteria and actinomycetes can be mainly used.
[0017]
Pollutants include oils, organochlorine compounds such as trichloroethane, trichlorethylene, and PCBs, aromatic hydrocarbons such as benzene, toluene, naphthalene, and phenol, as well as all substances that can be decomposed by microorganisms. The
[0018]
Contaminants containing pollutants are mainly contaminated soil, but also include industrial waste such as slag, incinerated ash, sludge, concrete waste, plastic waste, and waste wood.
[0019]
The predetermined work surface may be any place as long as contaminants can be spread and leveled for bioremediation. For example, the work surface can be used as it is by using the ground surface as it is. It is good also considering the concrete covering surface which coat | covered the ground surface with the concrete as a property material as a work surface. In such a case, contaminants can be prevented from flowing into the groundwater system. It should be noted that the leveling of the contaminants does not mean only leveling with the same thickness, but also includes, for example, leveling in a bowl shape or leveling in an embankment shape.
[0020]
The suction pump may be configured in any way as long as it can extract the substance causing the foul odor of the contaminants together with the air through the air suction pipe, and can be configured using, for example, a compressor.
[0021]
The deodorizing device is optional as long as it can remove substances that cause odors from the air drawn out from the air suction pipe.For example, a substance that causes odors with a predetermined adsorbent can be used. It is possible to make it adsorb. Adsorbents filled in the deodorizer include activated carbon, silica / alumina-based adsorbents, synthetic adsorbents such as molecular sieve carbon, zeolite, and acid clay, also called activated clay. What is necessary is just to select suitably according to the adsorption | suction characteristic of the substance used as.
[0022]
Note that the suction pump and the deodorizing device need to be connected in series, but it is arbitrary which is upstream, and the suction pump is connected to the tip of the air suction pipe, and the deodorizing device is connected to the outlet side of the suction pump. Alternatively, a deodorizing device may be connected to the tip of the air suction pipe, and a suction pump may be connected to the outlet side of the deodorizing device.
[0023]
The air suction pipe may have any configuration as long as the air in the contaminants flows smoothly into the hollow of the air suction pipe. For example, the air suction pipe is a hollow made of hard polyvinyl chloride having a large number of holes. It can be composed of tubes.
[0024]
The method of arranging the air suction pipes is arbitrary, and any arrangement method may be used as long as the internal space of the air suction pipe communicates with, for example, the soil particle gap space formed in the contaminant. Specifically, an air suction tube formed of a perforated hollow tube may be simply embedded in a contaminant, or a state in which a net is wound around the air suction tube to prevent clogging. But it doesn't matter.
[0025]
Here, when a groove is formed in a predetermined work surface, and the air suction tube is laid in a state surrounded by clogging prevention materials such as gravel, the air suction tube is positioned below the work surface. Will be installed.
[0026]
Therefore, when performing the work of stirring or tilling by adding decomposing bacteria and their nutrients and moisture to the pollutant, if the structure is as described above, the air suction tube becomes an obstacle and the stirring or tilling work cannot be performed. The situation can be avoided in advance.
[0027]
The clogging prevention material may be any material as long as it can prevent the holes formed in the air suction pipe from being clogged with contaminants and can ensure that air flows through the gaps between them, For example, it may be configured of sand, gravel or the like.
[0028]
The groove may be formed in any way as long as the air suction pipe can be laid inside while being surrounded by the clogging prevention material.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a pollutant decomposition system according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.
[0030]
FIG. 1 is a diagram showing a pollutant decomposition system 1 according to the present embodiment, and (b) is a cross-sectional view taken along line AA in (a). As shown in the figure, a pollutant decomposition system 1 according to the present embodiment includes an air suction pipe 4 that is placed in communication in a contaminated soil 3 that is a contaminant spread on a concrete covering surface 2 that is a work surface. And a suction pump 5 connected to the tip of the air suction pipe, and a deodorizing device 6 connected to the outlet side of the suction pump.
[0031]
Here, the contaminated soil 3 contains a pollutant to be decomposed by bioremediation, and various bad odors are generated from the contaminated soil 3 during the bioremediation. Is configured to remove substances that cause bad odor from the air drawn out from the contaminated soil 3 through the air suction pipe 4 by the suction pump 5.
[0032]
Substances that cause foul odors include pollutants themselves, nutrients to increase the decomposition activity of microorganisms that decompose these substances, intermediate products generated during the process of bioremediation, and substances generated during the organic decomposition process of microorganisms Etc. are included.
[0033]
The contaminated soil 3 is spread in a bowl shape so that the agitation work can be carried out while straddling the stirrer 10, and the width of the hail is adjusted to the distance between both wheels of the agitator 10. It is.
[0034]
As microorganisms used for bioremediation, indigenous bacteria such as bacteria and actinomycetes can be mainly used.
[0035]
Pollutants include oils, organochlorine compounds such as trichloroethane, trichlorethylene, and PCBs, aromatic hydrocarbons such as benzene, toluene, naphthalene, and phenol, as well as all substances that can be decomposed by microorganisms. The
[0036]
The air suction pipe 4 is constituted by a hollow pipe provided with a large number of holes 7 and is arranged along the longitudinal direction of the soil of the contaminated soil 3 as can be seen in the plan view shown in FIG. Each air suction pipe 4 is connected to a suction pump 5 through a header 9. The air suction tube 4 can be made of, for example, hard vinyl chloride or a plastic material.
[0037]
The suction pump 5 is constituted by a compressor, and can extract a substance that causes a bad odor of the contaminated soil 3 through the air suction pipe 4 together with air.
[0038]
The deodorizing device 6 is composed of an activated carbon adsorption tower filled with activated carbon as an adsorbent, adsorbs a substance causing bad odor from the air discharged from the suction pump 5, and exhausts the air from which the substance has been removed. The air is discharged from the mouth 8 to the atmosphere.
[0039]
The concrete covering surface 2 is a work surface formed by covering the ground surface with concrete as a water-impermeable material, and is a place for spreading and soiling contaminated soil 3 to perform bioremediation, and also serves as a water shielding layer. This also serves to prevent water containing pollutants in the contaminated soil 3 from flowing into the groundwater system of the surrounding environment.
[0040]
Here, the concrete covering surface 2 is formed with a groove 11 as well understood in the detailed cross-sectional view shown in FIG. 3, and is surrounded by gravel 12 which is a clogging preventing material in the groove. The air suction pipe 4 described above is laid.
[0041]
That is, the air suction pipe 4 is disposed so that the internal space 13 communicates with the soil particle gap space formed in the contaminated soil 3 through the gap between the gravels 12. In addition, the recessed part inner surface of the groove | channel 11 is also coat | covered with concrete, and is a water-impermeable groove | channel.
[0042]
As shown in FIG. 1 (a), the groove 11 is formed at the top of each paddle so as not to cause troubles such as derailment when the stirrer 10 travels across the bowl-like contaminated soil 3. It is desirable to provide it below.
[0043]
In the method for decomposing pollutants according to this embodiment, first, a groove is formed on the ground surface, and concrete is placed on the inner surface and the ground surface of the groove to form the concrete covering surface 2 and the groove 11.
[0044]
Next, the air suction pipe 4 is laid in the groove 11. When laying the air suction pipe 4, the surrounding area is surrounded by gravel 12.
[0045]
Next, the contaminated soil 3 containing the contaminant is spread on the concrete-coated surface 2 in a bowl shape and leveled. When the contaminated soil 3 is spread and leveled, the top of the ridge is placed above the groove 11 so as not to hinder the traveling of the stirrer 10.
[0046]
Next, the contaminated soil 3 spread in a bowl shape is stirred by the stirring traveling machine 10. In addition, it is necessary to add microorganisms that decompose pollutants and their nutrients or moisture before the agitation work, but this time may be performed in parallel with the agitation work or at the time of leveling. Alternatively, it may be performed in advance prior to leveling.
[0047]
Next, in this state, the contaminated soil 3 is left for a certain period of time to perform bioremediation, and the suction pump 5 connected to the tip of the air suction pipe 4 is operated to draw out the air in the contaminated soil 3. The air is deodorized by the deodorizing device 6 connected to the outlet side of the air and then released to the atmosphere. It should be noted that whether the suction pump 5 is continuously operated or intermittently operated may be appropriately determined depending on the situation, and may be operated only when the bad odor is strong.
[0048]
In addition, according to the decomposition | disassembly condition of the pollutant contained in the contaminated soil 3, while supplying a nutrient or water | moisture content for improving a decomposing microbe and its decomposition activity suitably, and stirring the contaminated soil 3 with the agitator traveling machine 10 as needed I do.
[0049]
In this way, contaminants such as oil and organic chlorine compounds themselves, intermediate products generated in the process of bioremediation, and other substances that cause malodors are collected together with air through the air suction pipe 4 by the suction pump 5. Then, it is deodorized and removed by the deodorizing device 6 and then released to the atmosphere.
[0050]
Moreover, as shown in FIG. 4, since the surrounding fresh air is taken in in the contaminated soil 3 by air suction, the inside of the contaminated soil 3 is maintained in an aerobic environment. Therefore, the activity of a degrading bacterium which is an aerobic bacterium is increased, and the degradation of pollutants is promoted.
[0051]
As described above, according to the pollutant decomposition method and system according to the present embodiment, the air in the contaminated soil 3 is sucked and deodorized and then released to the atmosphere, which causes a bad odor. There is no risk of the substance scattering or diffusing around the contaminated soil 3, and bioremediation can be performed without generating a bad odor.
[0052]
Therefore, it is possible to prevent a situation in which the work of workers who plow the contaminated soil 3 is hindered by the bad odor or adversely affect the surrounding environment.
[0053]
Further, according to the pollutant decomposition system 1 according to the present embodiment, the groove 11 is formed in the concrete covering surface 2 and the air suction pipe 4 is laid in the groove surrounded by the gravel 12. The suction pipe 4 is installed at a position below the concrete coating surface 2.
[0054]
Therefore, when performing the operation | work which stirs or tills the contaminated soil 3, the situation where the air suction pipe 4 becomes obstructive and cannot perform the cultivation work can be avoided beforehand.
[0055]
In this embodiment, the pollutant containing the pollutant is the contaminated soil 3, but instead of this, the present invention is applied to industrial waste such as slag, incineration ash, sludge, concrete waste, plastic waste, and waste wood. You may apply.
[0056]
Further, in this embodiment, the work surface is the concrete-coated surface 2, but when the work surface is not required to be water-impervious, for example, when a poorly permeable layer is present on the ground, the ground surface is directly applied to the work surface. It doesn't matter.
[0057]
In this embodiment, the groove 11 is provided on the concrete covering surface 2 and the air suction pipe 4 is laid in the groove. However, for example, when it is not necessary to stir the contaminated soil 3 The groove 11 may not be provided. In such a case, the air suction pipe may be laid on the work surface in a form of being embedded in the contaminants spread on the work surface.
[0058]
Further, in this embodiment, the stir-like contaminated soil 3 is agitated by the agitating traveling machine 10, but it is not always necessary to use the agitating traveling machine. For example, microorganisms that decompose pollutants and their decomposing activity are reduced. After adding nutrients or moisture for increasing to the contaminated soil, the mixture may be pre-stirred with a mixing mixer or the like and mixed evenly, and this may be spread on the concrete-coated surface 2 so as to have a substantially uniform thickness. .
[0059]
【The invention's effect】
As described above, according to the pollutant decomposition system according to the present invention, the air in the pollutant is sucked and deodorized and then released to the atmosphere. Bioremediation can be performed without generating a foul odor and no fear of scattering or diffusing around.
[0060]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a pollutant decomposition system according to the present embodiment, wherein (b) is a cross-sectional view taken along the line AA in (a).
FIG. 2 is a plan view showing an air suction pipe used in the pollutant decomposition system according to the present embodiment.
FIG. 3 is a detailed cross-sectional view showing a pollutant decomposition system according to the present embodiment.
FIG. 4 is a sectional view showing the operation of the pollutant decomposition method and system according to the present embodiment.
[Explanation of symbols]
1 Pollutant decomposition system 2 Concrete coating surface (work surface)
3 Contaminated soil (contaminant)
4 Air suction pipe 5 Suction pump 6 Deodorizing device 11 Groove 12 Gravel (clogging prevention material)

Claims (1)

In a pollutant decomposition system that decomposes and removes pollutants by bioremediation of pollutants containing pollutants such as oil and organic chlorine compounds,
An air suction pipe is arranged in communication with the contaminant spread on a predetermined work surface, and a suction pump and a deodorizing device are connected in series with each other at the tip of the air suction pipe. A pollutant decomposition system, characterized in that a groove is formed in the groove and the air suction pipe is laid in a state surrounded by a clogging prevention material such as gravel.

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