JP3491929B2 - Purification method of groundwater contaminated by soil contamination - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to remediation of soil pollution utilizing the degradation of biological chemicals.

More specifically, in-situ processing (IN SIT
E) is the restoration of soil pollution, and more precisely, it relates to a method for purifying contaminated groundwater due to soil pollution.

[0003]

2. Description of the Related Art In recent years, environmental pollution caused by hydrocarbons such as aromatic hydrocarbons, paraffin and naphthene, and organic chlorine compounds such as trichloroethylene, tetrachloroethylene and tetrachloroethane has become a problem. Many of these penetrate into the soil and are not decomposed but gradually dissolve in the groundwater and expand the contaminated area through the groundwater.

There is a strong demand for the establishment of a technique for preventing the recurrence of these serious environmental pollutions and for purifying the already polluted environment and returning it to its original state.

Examples of this environmental restoration technique include aeration treatment in which polluted groundwater is pumped up to separate volatile organic substances and adsorbed on activated carbon, contaminated soil is exposed to the sun or a heat source, and volatile organic substances are evaporated by heat. The heat treatment is performed, the contaminated soil is provided with a boring hole and vacuum extraction is performed to suck contaminants in a vacuum, and the contaminated soil is placed in a vacuum kettle and heated to be sucked and extracted.

These physicochemical treatments may be effective especially in the case of high concentration and local contamination, but when the contamination is low in concentration and in a wide range, the treatment speed and cost become problems. Further, even if these organic substances can be recovered by activated carbon, there are many substances which are usually hardly decomposable, and there is a problem that a treatment for further detoxifying them is required. As a method capable of solving these problems of physicochemical treatment, a soil restoration method using biological treatment by microorganisms has been studied in recent years.

If a method of decomposing pollutants with microorganisms, especially microorganisms capable of inhabiting soil, purification is naturally carried out by energy, the input energy is small, and the decomposition can proceed to water or carbon dioxide.

A large number of microorganisms that decompose persistent compounds that cause soil pollution, such as aromatic hydrocarbons and organic chlorine compounds, are known. However, when these degrading bacteria are sprayed as they are onto the actual contaminated soil, the growth and degrading activity of the bacteria are usually not sufficient.

The reason for this is not clear, but one is the difference in the distribution of the bacteria and the distribution of contaminants, and the other is that the survival of the bacteria and the activation conditions are insufficient. Is.

In order to overcome these problems, conventionally, a method of spraying bacteria together with a chemical that supplies nutrients and oxygen and a method of pumping the bacteria into the ground have been used.
However, the sprayed bacteria cannot be expected to have the same distribution as the already polluted harmful substances. The reason is that there is a difference in specific gravity with respect to the pollutant, a difference in chemical affinity with the soil, and a difference in the diffusion time of the contaminant and the bacterium. In addition, when the degrading bacteria are sprayed directly to the contaminated soil, the bacteria cannot be adapted to the soil and often die. This is considered to be due to lack of nutrients required by the bacteria, presence or absence of water and oxygen, competition with other microorganisms that live in the past, predation, and incompatibility with other physical conditions such as pH and temperature. For a system consisting of multiple materials for maintaining growth and activity of bacteria and nutrients,
It is difficult to widely supply these into the soil.

On the other hand, a method of pumping polluted groundwater and treating it physically or chemically or microbiologically has been attempted, but this method requires energy for pumping and treatment, and requires a ground facility for purification. However, there were many problems such as ground subsidence, hindrance to the downstream use of groundwater flow, and influence of downstream water change on the downstream ecosystem.

Various biological treatment methods are conventionally known from the viewpoint of treating contamination. Especially USP. 810th, 3rd
No. 85 (Filed May 12,1987 Sybron Chemicals, Ink) discloses that microorganisms stored in socks, their nutrients, metabolites, etc. are placed in a protective container and installed in the flow of sewage waste. This is because bacteria are widely diffused in the sewage flow, and sewage substances are decomposed. The major difference in groundwater pollution is that the concentration of pollutants in groundwater is extremely low compared to sewage, etc., and it is in an oligotrophic environment where there is little nutrition for the survival of microorganisms. Since it is an extremely clean and highly usable water resource as long as it can remove the pollutant, it is necessary to disperse a highly soluble material or a highly buoyant microorganism into groundwater, which causes new pollution. There are points that must be prevented as much as possible.

[0013]

Conventionally, it has been very difficult to artificially create a distribution corresponding to the distribution of pollutants on the ground surface by the method of directly supplying the fungus or its nutrients into the soil. In addition, it was difficult to control the conditions on the ground where the fungus survives or proliferates in the soil and maintains the degrading activity. Also, in terms of evaluating the survival and decomposition activity of the bacteria, it was a situation that could hardly be achieved by spraying into the ground. Further, under such insufficient control of bacteria, there is a problem that the survival / proliferation and decomposition activity of the bacteria cannot be fully expected, which is disadvantageous in terms of cost such as excessive supply of these bacteria. Furthermore, even after the contaminants have been purified, unnecessary bacteria and their nutrients may remain, which may cause secondary pollution.

On the other hand, since the degrading bacteria are supplied to the ground, it is physically difficult or costly to dig deep into the ground in a wide area. Further, it is difficult to make the distribution states of both pollutants the same because of the time lag between the time when the pollutants start to diffuse and the time when the biological decomposition products are supplied. In particular, the difference in diffusibility, in addition to this time difference, causes a difference in distribution to be increased due to a difference in specific gravity between the two and a difference in chemical or biological affinity with soil. Another reason that makes soil pollution remediation fundamentally difficult is that groundwater migration rates are very slow, and that the poorly soluble contaminants are adsorbed to the soil and the adsorption equilibrium when it dissolves in water. It takes time for the slowly progressing inflowing unpolluted groundwater to reach equilibrium with the soil adsorbing pollutants. This suggests that it is difficult to obtain the effect even if the groundwater is abruptly moved from the outside. In other words, it can be inferred from the fact that the method of pushing out the contaminated groundwater by the suction of the pump in the contaminated area and the forced rise of the groundwater level from the upstream side is unexpectedly ineffective.

Further, it is physically possible to provide a barrier wall in a plane shape or an adsorbent or a decomposer of a pollutant in a net shape on the downstream side of groundwater in the contaminated land, but it is an enormous work. And there was a problem that cost.

[0016] An object of the present invention is to solve the above-mentioned problems in soil remediation, and to eliminate the adverse effects of soil pollution by purifying the groundwater pollution generated from soil pollution. It provides a method for purifying contaminated groundwater.

[0017]

The present invention provides a tubular body or
Is a boring hole in which a cylindrical container is inserted and
At least upstream of lower seepage water or upstream of groundwater flow
Also, one or more are arranged, and inside the tubular body or tubular container.
Degradation of groundwater passing through rivers to decompose harmful pollutants
Floating or dissolving fungal and microbial activity maintaining material,
Move to contaminated areas with groundwater to remove the harmful pollutants.
Contaminated groundwater due to soil pollution characterized by damaging
It is a purification method. The present invention also provides a tubular body or a tubular body.
Underground infiltration along a source of contamination through a borehole with a container inserted
At least one upstream of the water or upstream of the groundwater flow
It is arranged as above and passes through the inside of the tubular body and the tubular container.
Of groundwater and enzymes that decompose harmful pollutants
Suspend or dissolve the activity maintaining material, and with the groundwater
Move to the contaminated area and reach the contaminated area of the hazardous pollutant
When the soil is characterized by detoxifying the harmful pollutants
This is a method of purifying contaminated groundwater due to soil contamination.

The present invention also provides a tubular body or a tubular container.
At least the inserted borehole should surround the source.
A cylindrical body consisting of two or more arrangements upstream of the pollution source.
From the cylindrical container, the microbial content that decomposes harmful pollutants
Material for sterilization and maintenance of microbial activity or harmful pollutants
Enzymes and their active substances that decompose
The area that floats or dissolves and in which contaminants dissolve
While detoxifying harmful pollutants, the remaining pollutants
Furthermore, when passing through the tubular body on the downstream side,
Contaminated groundwater due to soil pollution characterized by detoxification
It is a purification method of.

The present invention will be described in detail below.

The route in which soil pollution substantially affects the environment varies depending on the nature of the pollutant and the pollution state. However, in the case of soil pollution due to an organic chlorine-based solvent, which has been particularly problematic in recent years, the solvent leaking underground penetrates deep into the ground and gradually dissolves in groundwater. In many cases, the problem occurred only when this groundwater was directly used in the groundwater downstream region, or when the groundwater flowed out from the ground or even outflowed to the river.

If the contaminated soil is local and at the beginning of the contamination, the problem can be solved by directly treating the contaminated soil. However, in many of today's problems, organochlorine-based solvents have been widely used and more than 10 years have passed, and it is often the first time that problems are noticed. Is adsorbed on the groundwater and gradually dissolves in the groundwater passing through it.
The above-mentioned groundwater pollution affects the environment.

Here, a typical contamination mechanism of an organic chlorine solvent having a large specific gravity will be described.

FIG. 7 is a schematic diagram of an underground cross section of a typical organochlorine-contaminated soil.

First, the solvent that has penetrated from the pollution source C to the soil I (top soil), H (loam layer), G (sand layer) and F (sand gravel layer) is adsorbed to the soil, and excess solvent that cannot be adsorbed is successively admitted to the lower layer soil. And adsorption progresses. The distribution of pollutants at this time has a steep mountain shape, and as long as there is soil that can penetrate and adsorb, the distribution in the horizontal direction does not proceed so much.

Next, when reaching the formation E (silty clay layer) where the solvent cannot sufficiently permeate, the solvent will stay in the vicinity thereof. Next, when rainwater or groundwater supplied from the ground is present, the solvent is in an adsorption equilibrium between the soil and water, and the solvent dissolves in the water with a constant distribution coefficient. In many cases, the solubility of organic chlorine-based solvents is low and is several hundred ppm. Although this number is physically low in terms of solubility, it is a large number for environmental pollution.

Further, the adsorption equilibrium (keeping a constant value by the distribution coefficient) of pollutants on soil and groundwater is re-equilibrated due to the new inflow of groundwater, and the dissolved solvent passes through the water. Pollution spreads. The groundwater flow J occurs below the groundwater level D, but the adsorption of the gravel layer is less than the adsorption of the solvent compared to the loam layer and the silt layer. This means that the gravel layer in which the groundwater flow is likely to move increases the spread of contaminants. It will be improved.

The present invention provides a continuously effective pollution purification measure in consideration of such a pollution mechanism. That is, in many cases, it is difficult to dig up and remove the contaminated solvent that has penetrated deep into the soil together with the soil. The depth of infiltrated soil varies from stratum to stratum, but can reach several meters to several tens of meters. There are often operating factories, facilities, houses, etc. on the ground above the polluted areas. Also, of course, the deeper the area, the wider the contaminated area. The slow movement of groundwater takes a long time before the contamination is detected, which also causes the contamination area to expand. Therefore, in some cases, complete purification becomes impractical for the entire contaminated area.

On the other hand, when a deep underground drilling survey is conducted, it becomes clear that the direction of the groundwater flow is fixed as in the case of the aboveground river.

In this way, the repair for soil purification is
It is essential to cut off the pollution source, but secondly, it is important to purify the groundwater flow of the generated groundwater pollution.

The present invention aims to purify a groundwater flow based on these pollution mechanisms.

Next, a method for decomposing biologically harmful chemical substances will be described.

Hazardous chemical substances causing soil pollution, which is a problem in the present invention, are hardly decomposable compounds such as aromatic hydrocarbon compounds and organic chlorine hydrocarbon compounds. Many microorganisms that decompose these are known, and some of them are known to have degradative enzymes. However, even if these microorganisms or enzymes are directly applied to the actual contaminated soil, no sufficient effect can be expected against harmful chemical substances in the soil.

One of the reasons is that the distribution characteristics of these microbial materials and chemical substances are different, and the time course of the distribution cannot be the same.

Another reason is that even if the decomposing activity is obtained under a certain condition on the ground such as an incubator, the same habitation condition cannot be obtained in the ground.

When the microbial material is sprayed directly on the ground or in the ground, the microbial or enzyme concentration in the soil is rapidly decreased with time, as compared with the initial concentration at the time of spraying.

Therefore, it is necessary to take measures such as frequent and large-scale seeding of microbial material, which causes inconvenience in processing time cost and the like. Therefore, there is a strong demand for a method in which microorganisms survive, proliferate, and maintain their activity in soil containing harmful substances. Similarly, in the case of enzymes, it is necessary to secure conditions for maintaining activity in soil.

Further, the effect of these purifications cannot be evaluated unless the decomposition activity is maintained in the soil by any method.

It is rather difficult to directly evaluate the activity maintenance of microbial materials released into soil, and it is also difficult to control the activity of these microbial materials from the ground. Although it may be possible to indirectly monitor harmful substances using observation wells, etc., it is not possible to expect real-time response, and factors other than microorganisms may enter and make analysis difficult.

These problems can be solved by integrally forming a material for maintaining the survival, growth, and activity of microorganisms or microbial metabolites in a soil into a water-permeable cylinder and inserting it into a contaminated groundwater flow. Can be solved.

The survival / proliferation / activity-maintaining materials cannot always be distinguished in a strict sense.

The survival material is, in part, a habitat space for the microorganisms that is protected when the microorganisms are predated by other microorganisms or microbes in the ground or compete with each other.
In some cases, it also serves as an immobilization carrier in order to prevent effective microorganisms from diffusing and disappearing in groundwater. The growth material corresponds to the culture medium of the microorganism. Microbes grow with nutrients and contribute to the decomposition of harmful substances. The activity-maintaining material is intended to substantially promote the decomposition of harmful substances, and may be indistinguishable from nutrients. When a specific substance cannot be directly used as a nutrient, the microorganism decomposes this specific substance, so that an inducing substance (inducer) produces a degrading enzyme to promote the decomposition. Decomposition of harmful substances is made possible by enzymes produced by microorganisms at this time. Here, the material necessary for producing this harmful substance-degrading enzyme was used as the activity maintaining material.

This indicates that harmful chemical substances can be decomposed without using the microorganisms themselves, even with the enzyme, which is a metabolite of the microorganisms. When an enzyme is used instead of the microorganism, a carrier that holds the enzyme and a mineral or the like are required for the enzyme to exhibit a degrading activity.

Next, specific materials will be shown. As the microorganism, a material whose degrading activity has been confirmed is used, and it is selected from those belonging to the following genera.

Saccharomyces, Hansenula, Candida,
Micrococcus, Staphylococcus, Streptococcus, Leuco
nostoa, Lactobacillus, Corynebacterium, Arthrob
acter, Bacillus, Clostridium, Neisseria, Escheri
chia, Enterobacter, Serratia, Achromobacter, Alc
aligenes, Flavobacterium, Acetobacter, Nitrosomo
nas, Nitrobacter, Thiobacillus, Gluconbacter, Pse
As the udomonas, Xanthomonas, and Vibria survival materials, various microorganism carriers that have been used in bioreactors conventionally known in the pharmaceutical industry, food factories, wastewater treatment systems, etc. are used as materials that provide a habitat space for microorganisms. For example, porous glass, ceramics, metal oxides, activated carbon, kaolinite, bentonite, zeolite, silica gel, alumina, anthracite and other particulate carriers, starch, agar, chitin, chitosan, polyvinyl alcohol, alginic acid, polyacrylamide, carrageenan, Gel carriers such as agarose and gelatin, ion exchange resinous cellulose, ion exchange resins,
There are cellulose derivatives, glutaraldehyde, polyacrylic acid, urethane polymers and the like. In addition, natural or synthetic polymer compounds are also effective, such as cellulose-based cotton, linen, paper made from pulp materials, or polymer acetate modified from natural products. Cloths made of synthetic polymers such as polyester and polyurethane can also be used. It is preferable that these have good adhesion to microorganisms and have fine gaps.

As the growth material, those used in the medium for culturing microorganisms can be used. For example, broth medium, M9 medium, L medium, Melt extrac
t, MY medium, nitrifying bacteria selective medium and the like are effective, and liquid ones can be treated as solid or semi-solid by using together with a gel substance such as agarose gel.

As a material that provides a living space and a material that also serves as a nutrient, many examples can be found in compost materials known in agriculture and forestry. That is, dried plant remains such as straws and sawdust of rice grains such as straw, rice bran, okara, and squeeze residue of sugar cane, and crabs and shrimp shells also have microscopic voids and at the same time serve as microbial degradable nutrients.

As the activity-maintaining material, there are those which are known as inducers when the degrading bacteria have been specified, but in natural materials, these are usually present in a mixed state and cannot be specified. There are many things. Particularly in the case of mixed microorganisms, metabolites of one microorganism often form a symbiotic system that functions as an inducer of another microorganism. Therefore, when a mixed microorganism is used, a natural organic substance in which various substances coexist is effective. As the inducer that can be identified, methane is used in methane-utilizing bacteria, toluene, phenol, omp cresol and the like are used in aromatic-utilizing bacteria, and ammonium salts are used in nitrifying bacteria.

Taking as an example the bacteria known to be capable of degrading trichloroethane, more than ten species have been discovered and isolated so far. Of these, the representative ones can be roughly divided into two depending on the type of the substrate.

That is, it is a methane-utilizing bacterium and an aromatic compound-utilizing bacterium such as phenol. The representative of the former is Methylocystis sp. Strain M, which has methane monooxygenase.
(Agri.Biosci.Biotech.Biochem., 56,486 (1992), 56,
736 (1992)), Methylosinus trichoseporium OB3b (Am.C
hem.Soc.Natl.Meet.Div.Environ.Chem., 29,365 (1989),
Appl.biochem.Biotechnol., 28,877 (1991)), the latter of which is Acinetobactor sp.strain G4 (Appl.) Having toluene monooxygenase or toluene dioxygenase.
l.Environ.Microbiol., 52,383 (1986), 53.949 (198)
7), 54,951 (1989), 56,279 (1990), 57,1935 (199)
1)), Pseudomonas putida Fl (Appl.Environ.Microbio
l., 54, 1703 (1988) and 54, 2578 (1988) are typical examples. Among these, regarding the aromatic compound-assimilating trichloroethane (TCE) -degrading bacterium, the enzyme that decomposes TCE is an inducible enzyme that is induced by aromatic compounds such as phenol and toluene. In order to decompose the substance, a material containing an aromatic compound or decomposed into an aromatic compound is used as the activity maintaining material.

When an enzyme material is used, no survival material or growth material is required, but it is necessary to mix minerals necessary for the enzyme to exhibit activity, such as Fe ²⁺ and coenzymes such as NAPH. is there.

In principle, an enzyme should have a permanent degrading effect if it exists in the system, but in reality it deactivates depending on the conditions of use. Therefore, it is necessary to mix and integrate the materials necessary for this enzyme to maintain its activity as long as possible. Examples of enzymes include toluene monooxygenase, toluene oxygenase, ammonia monooxygenase, methane monooxygenase and the like.

The water-permeable tubular body is an integrated body of all or a part of the above substances. If any of these materials can be formed as a water-permeable tubular body, it is tubular. It is obtained by forming a body and impregnating it with other materials. When each is in the form of powder or particles, it is formed by using a binder. Alternatively, it is possible to store these materials in a water-permeable container. As the container material, plastic, metal, paper, cloth or the like is used as long as it can impart a water-permeable structure and can maintain the outer shape.

In this case, the hydraulic conductivity of the tubular body and the tubular container is 5
It is preferably in the range of × 10 ^-6 to 1 × 10 ^-2 cm / sec. When the water permeability is larger than this, the residence time of the contaminated water in the tubular body or the tubular container is shortened, and the decomposition is degraded. The problem of not progressing sufficiently arises. On the other hand, if it is small, the residence time in the tubular body or the tubular container will be long, but the throughput will be small and the efficiency will be reduced. Further, the permeability coefficient may be appropriately determined in consideration of the permeability and the pollutant concentration of the surrounding soil, the speed of the groundwater flow, etc., more preferably 1 × 1.
It is in the range of 0 ⁻⁵ to 1 × 10 ⁻³ cm / sec.

The water permeability is determined according to JIS A1218 “Soil permeability test method / constant water level permeability test”.

A soil purification apparatus which can be used in the present invention will be described with reference to FIG. The stratum in Figure 4 is topsoil or loam layer 5
There is a sand layer 58 and a gravel layer 59 under 7, and a hardly permeable or impermeable layer 61, on which a groundwater flow flows in a direction 62, and a contaminated groundwater flow portion 60 is indicated by diagonal lines. is there.

The diameters of the cylinders 53, 54 and 55 are made smaller than the diameter of the boring hole to facilitate the insertion. The boring hole is for the purpose of preventing it from being filled with earth and sand,
It is preferable to provide a tubular guide 52 having a water-permeable structure.
The material is not particularly limited, but a circle with a small hole, a vinyl pipe, or a metal tube with a stitch structure is used. The length of the tubular body is not particularly limited, but the block is divided so as to be easily inserted into the boring hole. The divided blocks can be used either with the same decomposition material composition or with different compositions.
Used to insert into a boring hole. When the contamination concentration is partially different in the depth direction of the boring hole for purification,
Blocks with different resolutions can be combined and used. Further, when there is an uncontaminated formation or an impermeable layer, a dummy cylindrical body containing no decomposing material for harmful substances, or simply the wire 51 is used in combination. The divided tubular bodies have a structure that can be connected to each other, and when they are inserted on the ground, they are connected to each other one by one and put into the boring hole, without using a long tubular body A state can be supplied. Instead of connecting the tubular bodies to each other, there is also a method in which a connectable connecting body is separately provided and the tubular bodies are attached to the connecting body. By using a thin rod-shaped connecting body whose central portion can be connected to a tubular body of a decomposed material having a hollow portion, sufficient strength can be maintained even in a long boring hole. If the connecting body has a string-like shape or a flexible hook-like connecting part, it can be easily inserted even if the boring hole is slightly curved. Where groundwater is springing out into the boring hole, the weight 56 can be attached to the lower portion of the tubular body to ensure the insertion of the tubular body.

Next, a method for purifying contaminated groundwater using such a tubular body will be described. A survey of the contaminated area is conducted prior to inserting the cylinder into the borehole.

In many cases, the pollution source can identify the ground facility and the burial place of the pollutant from past data, and the polluted state spreading toward the downstream side of the groundwater is mapped by boring in a grid pattern around the pollution source. To do. If this is not the case, it is necessary to carry out the drilling survey from the location where the contamination was found to the upstream side of the groundwater flow in a grid pattern.

At the time of this boring survey, data such as geological formation, geology, and direction of groundwater flow are also accumulated.

Once the area of contamination and the diffusion direction of the pollutants have been analyzed, generally possible physical cleaning measures are implemented. The present invention is effectively used for removing residual contaminants when physical purification measures cannot be carried out or after possible measures have been taken.

FIG. 5 shows an arrangement example of the purifying device .

The pollutant usually has a pollutant C as a core, and a pollutant region spreads radially in the downstream direction of groundwater . Purification bow
Multiple ring holes (B ₁ ~
B _n ) It is preferable to arrange them at a high density. However, if it is too close to the pollution source, pollutants with high specific gravity may not be able to be trapped in the region where the contaminant penetrates in the depth direction beyond the saturation adsorption with soil, so caution is required. Is.

When the pollution source on the ground can be identified and the distance L at which the infiltrated contaminant reaches the impermeable layer or the impervious layer is known, the cylindrical body is arranged at a radius of at least 1 to 50 times L as the center of the pollution source. Preferably. The reason for this is that if it is unnecessarily close to the pollution source, the pollutant cannot be completely captured, and if it is too far away, a large number of boring holes must be provided when the cylindrical body is installed and used at a high density.

Although the method of installing the cylindrical body or the cylindrical container on the downstream side of the pollution source has been described, the other method is to install the cylindrical body or the cylindrical container (A _{1 to An} ) on the upstream side of the pollution source. Is.

FIG. 6 is a diagram showing an example of the upstream side arrangement of the purifying device .

At this time, the microorganism decomposing the pollutant and the material for maintaining its activity are dissolved or suspended by the groundwater flow to reach the contaminated area, and the harmful pollutant is rendered harmless in this contaminated area. Similar methods can be used for enzymes.

The arrangement on the upstream side should be as close as possible to the pollutant source, the microorganisms or enzymes can efficiently approach the pollutants, and the diffusion of the activity-maintaining material is close to that of the microorganisms and their metabolites. Is obtained.

By disposing the cylindrical body or the cylindrical container so as to surround the area of the pollution source, more efficient purification can be achieved. Depending on the situation, it may be installed on the downstream side and the upstream side.

A slightly different characteristic is required between the case where the tubular body or the tubular container (hereinafter referred to as the tubular body) is arranged on the upstream side of the pollution source and the case where it is provided on the downstream side. Microorganisms and activity-maintaining materials in the upstream tubular body tend to flow out due to groundwater, and these necessary components must be selected so that they have an effect in the area where they are not separated from each other.
At the same time, care must be taken to ensure that these materials do not remain in groundwater and cause secondary contamination by this material. On the other hand, if it is provided in the downstream region, it is possible to configure the material required for decomposition with a material that is difficult to elute outside.
This has the disadvantage that only contaminated water passing through the tubular body can be purified. Therefore, it is necessary to change the elution property and non-elution property of the decomposed material according to the conditions of the contaminated land. Usually, it is preferable that the cylindrical body has a resolution of contaminants in the range of 1 to 100 times the diameter. When the decomposition range is narrow, it is natural that the arrangement density of the cylindrical bodies must be increased, while when it is too wide, one of the multiple constituent materials is excessively supplied and unnecessary components remain. , Cause uneconomical. In any case, these elution components must be harmless materials after the pollutants are decomposed or when they do not contribute, but it is desirable that the materials be decomposed by indigenous bacteria in the ground to be harmless. Is selected.

It is preferable that the diameter of the boring hole and the tubular body of the decomposed material is large, but it is appropriately selected from the boring technique and the cost. Of course, to get the same level of cleaning effect, the number of holes must be increased when using a smaller diameter. Also, the water permeability of the decomposed material needs to be appropriately designed with respect to the diameter. It may be ideal to arrange the boring holes radially in the downstream direction of the groundwater with high density centering on the pollution source, but there is a drawback that many boring holes are installed. In the present invention, it is effective to arrange a plurality of dust lines in a direction in which the groundwater flow is blocked in a certain area in the radially polluted groundwater downstream region. As a site on which the tubular body used in the present invention effectively acts, a large effect is obtained in a portion that directly permeates the tubular body, but the habitation of microorganisms eluted from the tubular body and the activity maintaining material have a predetermined concentration A purifying effect can be brought within the range kept at. This varies depending on the material used and cannot be generally limited, but it can be several times as large as the diameter of the boring hole, and the hole arrangement density can be reduced by measuring the effective area.

The tubular body used in the present invention has a feature that it can be properly taken out from the boring hole to inspect the state of microorganisms or enzymes. Also, from this result,
These materials can be replenished and replaced arbitrarily. In addition to directly assessing these biological activities, a research well is installed downstream of this to monitor the items related to pollutant concentration and microbial activity constantly or at any time, and feed them back to the microbiological control of the tubular body. It is also possible to do so.
Further, when the purification is completed, these materials can be removed, and there is little concern that they will remain in the soil and cause secondary pollution.

[0072]

EXAMPLES Reference Example 1 cylindrical body and an example of a tubular container shown in FIGS.

FIG. 1 shows a porous cylindrical body 1 formed of a plurality of materials capable of biologically decomposing pollutants.
Reference numeral 11 is a through hole through which the rod-shaped connecting body can pass. 1
Reference numeral 2 is a void provided so as to obtain sufficient water permeability.
The void has a macro size and is about 0.1 to 5 mm, and the voids are connected to each other so that water can easily pass through the tubular body. This void can be easily obtained by using a plant as a constituent material. For example, sawdust, rice bran, straw crushed and the like. Also 0.1-5m
An inorganic material composed of particles of about m can also be used. In the cylindrical body using microorganisms, those having a micropore of about 100 to 1 micron are used as these particulate constituting materials. This serves as a space for microbial adsorption and habitat. The tubular body 1 of FIG. 1 is held by the connecting body 2 of FIG. 2 and can join a plurality of tubular bodies. The rod-shaped connecting body 21 passes through the through hole 11 of the cylindrical body and is supported by the flange 22. A female screw 23 is provided at the center of the lower side of the flange 22, while a male screw 24 is provided at the upper part of the rod-shaped coupling body. The plurality of divided tubular bodies are similar to the screw 23 of the rod-like connecting body 21.
And 24 can be connected to each other.

Another example is shown in FIG.

FIG. 3 shows a cylindrical container having a hole of 0.1 to 5 mm on its side surface. A plurality of materials capable of biologically decomposing pollutants are stored in the hollow portion 34 in the container and used as the cylindrical body of the present invention. The top lid 32 of the container has 33 screws to which the screws 35 on the top of the container can fit. A hook 31 is provided at the center of the lid so that a plurality of the hooks can be connected to each other, while a hook 37 for connecting the hook downward is provided below the container.

The microorganism to be used is not particularly limited as long as it is a bacterium in which the decomposition of the target pollutant chemical substance has been confirmed, but in this example in which the resolution is specified by the target pollutant, phenol is used. Strain KK with resolution
01 (Deposited with the Institute of Microbiology, Institute of Industrial Science and Technology, Ministry of International Trade and Industry, March 11, 1992, Deposit No. FERM P-1286
An example using 9) will be shown. 500 parts of zeolite as a material for maintaining survival are added to M9 medium (yeast extract 0.05
% Of KK01 strain well mixed with 1000 parts of oak scraps of oak and kunugi, and 300 parts of polyvinyl alcohol (molecular weight of about 20,000 to 50,000, crystallinity 95% 2
0% aqueous solution) / 50 parts, kneaded and solidified, diameter 10 cm, length 5
It is formed into a cylindrical body 1 having 0 cm and a hollow portion having a diameter of 3 cm at the center. In an example of using a container, rice straw 10 cut with a size of 3 cm using 50 parts of KK01 strain as a microorganism is also used.
It was thoroughly dusted with 00 parts and filled in a polyester container having a diameter of 10 cm and a length of 50 cm and a thickness of 0.6 mm in which a large number of holes of about 1 mm were provided on the side surface of the container to obtain a water-permeable cylindrical body.

Examples of constituent materials of the tubular body and the tubular container are shown in Table 1.
Shown in.

[0078]

[Table 1] Example 1 Purification device 1 with boring hole arrangement Aquifer The water surface is around 10 m, and a 14 cm diameter boring hole is excavated at 15 m in the groundwater downstream region of a model underground pollution source of a closed system with an impermeable layer around 14 m. A vinyl chloride pipe having a diameter of 12 cm and a thickness of 5 mm having a large number of small holes of 0.1 to 2 mm was inserted into the pipe, and the pipe was used as a tubular guide 52. The main connection is made, a weight of 3 kg is attached to the lower part, the wire is connected to a stainless steel 3 mm stranded wire 12 m, and is lowered about 10 m. The model groundwater is moved at a flow rate of 1 m / day. When 10 ppm of trichlorethylene was dissolved in the groundwater and the measurement was carried out periodically on the downstream side of the pipe for 10 days, the radius of the pipe downstream was 50 from the 3rd day.
1ppm or less in cm, 0.1ppm in the 10cm downstream of the pipe
Met.

[0079] The cylindrical container of Example 2 shown in Example 2 in Table 1 was used in the same configuration as in Example 1, was subjected to downstream in 10 days regular measurements of the tube, the tube downstream of the third day 2ppm or less at a radius of 50cm,
The content within 10 cm downstream of the tube was 0.3 ppm.

[0080] The cylindrical vessel Example 3 shown in Example 3 in Table 1 was used in the same configuration as in Example 1, was subjected to downstream in 10 days regular measurements of the tube, the tube downstream of the third day It was 0.7 ppm or less at a radius of 50 cm, and 0.1 ppm within 10 cm downstream of the tube.

[0081] The cylindrical container of Example 4 shown in Example 4 in Table 1 was used in the same configuration as in Example 1, was subjected to downstream in 10 days regular measurements of the tube, the tube downstream of the third day It was 0.5 ppm or less at a radius of 50 cm and 0.05 ppm within 10 cm downstream of the tube.

Example 5 Purification Device with Boring Hole Arrangement 2 A pipe was inserted 13 m below the model underground pollution source of Example 1 , water in which 10 ppm of trichlorethylene was dissolved was injected, and Table 1 was located at a position corresponding to 1 m upstream. A boring hole was provided in which the cylindrical body example 4 shown was inserted. The model groundwater is moved at a flow rate of 1 m / day. Downstream of the pipe 2
When the measurement was carried out at the position m, the pipe downstream radius was 1 m and 3 ppm was 3 ppm when the tubular body was not inserted. However, when the tubular container example 4 shown in Table 1 was provided in the same manner as in Example 1 , the pipe It was 0.8 ppm at the downstream radius of 1 m.

[0083]

According to the present invention , groundwater pollution caused by soil pollution can be substantially purified. The management on the ground can be ensured, it can be economically executed, and the effect can be continuously exerted. Further, when the purification is sufficiently completed, it is easy to recover all the materials and devices including the bacterial cells, and it is possible to achieve the repair without secondary contamination.

[Brief description of drawings]

FIG. 1 is a perspective view of a tubular body usable in the present invention.

FIG. 2 is a perspective view of a connecting body used in the tubular body usable in the present invention.

FIG. 3 is a perspective view of a cylindrical container usable in the present invention.

FIG. 4 is a diagram showing an example of a stratum to be purified .

FIG. 5 is a diagram showing an example of a downstream side arrangement of the purification device .

FIG. 6 is a diagram showing an upstream arrangement example of a purifying device .

FIG. 7 is a schematic diagram of an underground cross section of organochlorine-contaminated soil.

[Explanation of symbols]

1 tubular body 2 connected body 3 cylindrical containers 11 through holes 12 voids 21 Rod-shaped connected body 22 Flange 23, 24 screws 31,37 hooks 32 Top cover 33,35 screws 51 wire 52 Tubular guide 53, 54, 55 cylinders 56 weight 57 ROHM layer 58 sand layer 59 Gravel layer 60 Contaminated groundwater flow 61 Slightly impermeable layer or impermeable layer

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masanori Sakuranaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Ken Ken Miyazaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Ki (56) References JP-A-2-164936 (JP, A) JP-A-5-92195 (JP, A) JP-A-1-256389 (JP, A) JP-A-5-115862 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C02F 3/00-3/10 B09C 1/10

Claims (3)

(57) [Claims] 1. A container having a cylindrical body or a cylindrical container inserted therein.
Through the ring hole upstream of the underground seepage water along the pollution source or
Arrange at least one or more upstream of the groundwater flow,
Groundwater that has passed through the inside of the tubular body and the tubular container is harmful to the soil.
Microbial degrading bacteria that decompose dye materials and microbial activity maintaining material
Floating or dissolving the material, along with the groundwater, in the contaminated area
Characterized by moving and detoxifying the harmful pollutants
Purification method of contaminated groundwater due to soil pollution. 2. A container in which a tubular body or a tubular container is inserted.
Through the ring hole upstream of the underground seepage water along the pollution source or
Arrange at least one or more upstream of the groundwater flow,
Groundwater that has passed through the inside of the tubular body and the tubular container is harmful to the soil.
Floating enzyme that decomposes dyes and material that maintains enzyme activity
Or it dissolves and moves to the contaminated area with the groundwater,
When reaching the polluted area of the harmful pollutant, the harmful pollutant
Contaminated land due to soil pollution characterized by detoxifying quality
How to purify sewage. 3. A bow into which a tubular body or a tubular container is inserted.
Arrangement of at least two so that the ring hole surrounds the pollution source
Consisting of a cylindrical body or a cylindrical container on the upstream side of the pollution source.
And microbial degrading bacteria that decompose harmful pollutants
Material activity maintaining material or enzyme that decomposes harmful pollutants
And its active substances float or dissolve with the groundwater flow.
The harmful pollutants in the area where the pollutants dissolve.
The pollutants that have become harmful and that remain are the cylindrical bodies on the downstream side.
Further detoxifying the harmful pollutants when passing through
A method for purifying contaminated groundwater by soil pollution.