JPH0880484A - Method for purifying contaminated soil and contaminated ground water - Google Patents

Abstract

PURPOSE: To provide a purifying method which surely executes uniform impregnation of a decomposing material in a depth direction, impregnation to a specific range on a line or plane, impregnation to a specified concn., impregnation in a short time, repetitive impregnation and impregnation of plural materials in soil purification. CONSTITUTION: An outside pipe 21 having many stages of impregnation ports 23 provided with valves 33 to allow easy passage to the discharge side alone are inserted into the soil. Packing materials are packed around the pipe and an inside pipe 21 having an ejection port 28 is inserted into the pipe by sealing the upper and lower impregnation ports with packers 29. A liquid microorganism material is impregnated under pressurization from the desired impregnation ports via the ejection ports 28 into the ground strata. The inside pipe is moved in the depth direction after the completion of one step of the impregnation and thereafter the pressure impregnation stages are successively repeated, by which the liquid microorganism material is supplied into the contaminated ground strata.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil remediation (restoration) method for biologically decomposing chemical substances as pollutants, and more specifically to an in situ treatment (IN SITU) soil remediation method. To be precise, it relates to a method for supplying a liquid microbial pollutant decomposing material to a contaminated underground.

[0002]

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. Most of these penetrate into the soil, are not decomposed, and gradually dissolve in the groundwater to expand the contaminated area through the groundwater.

It is strongly desired to establish 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 technology 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, or the contaminated soil is placed in a vacuum kettle and heated to be sucked and extracted.

These physicochemical treatments may be effective especially when the concentration is high and local pollution is severe.
When contamination is low concentration and wide range, processing speed and cost become a problem. Further, even if these organic substances can be recovered by the activated carbon, there are many substances that are usually hardly decomposable, and there is a problem that a treatment for further detoxifying the substances is required.

As a method for solving these problems of physicochemical treatment, a soil remediation method using biological treatment by microorganisms has been studied in recent years.

If microorganisms, especially microorganisms that can live in the soil, decompose pollutants, purification is carried out by natural energy, the input energy is small, and the decomposition proceeds to water and 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 microorganism-decomposing materials are directly sprayed on the actual contaminated soil, the supply of the materials usually becomes excessive or deficient or uneven, and proper purification may not be performed.

This is because "distribution of pollutants" and "dispersion of microbial decomposition material" are difficult to be the same due to differences in time and physicochemical properties.

In order to overcome these problems, a method of forcibly arranging the microbial decomposition material in the ground or a method of pumping the material with a pipe inserted into the soil layer has been used.

Conventional USP 5,120,160 and DE3,
839, 093, USP 5, 080, 782, USP
5, 032, 042, USP 4, 401, 569, etc., propose a method for biologically purifying pollutants by supplying microorganisms and nutrients into the ground. However, these are not the techniques for guaranteeing the accurate distribution of the biodegradable material, that is, the concentration distribution of depth and spread.

Further, as described in US Pat. No. 4,442,895, a method of injecting a pressurized fluid into a formation to generate cracks in the fields of oil and natural gas collection, soft ground solidification, etc. Although known, it is not a complete technique as a means of delivering degradable material into the formation as contemplated by the present invention.

In USP 5,133,625, a method is proposed in which an inlet is provided at the tip of a pipe, and liquid microbial decomposing materials are sequentially pressed while being inserted into the ground.
In order to inject liquid and gas sequentially, it is necessary to remove the previously injected liquid or gas at a fixed depth, or to install two injection pipes for liquid and gas, which is complicated. is there.

USP 5,032,042 discloses a technique in which a pipe for introducing compressed air into the ground is provided and a packer is provided to successively form cracks in the depth direction. Since it does not have it, it is unsuitable when sequentially injecting a liquid and a gas or two kinds of liquids, or when injecting at a predetermined time, and has a drawback that the injectate moves toward the outer wall of the tube.

Although a method of pumping polluted groundwater and treating it physically or chemically or microbiologically has been attempted, this method requires energy for pumping and treatment,
There are many problems such as the need for ground facilities for purification, further ground subsidence, hindrance to the downstream use of groundwater flow, and effects on downstream ecosystems due to changes in underground water.

[0016]

[Problems to be Solved by the Invention] Conventionally, in the method of directly supplying a microorganism decomposing material such as bacteria and its nutrients into the soil,
It was very difficult to artificially create a distribution corresponding to the distribution of pollutants on the ground surface. Under such insufficient distribution control of bacteria, it is disadvantageous in that the efficiency of decomposition such as excessive supply of these is lowered and the economy is low. On the other hand, it is physically difficult or costly to dig deep into the ground in a wide area in order to supply the decomposition material to the ground. In addition, when the degradable material is naturally diffused by simply spraying it from the ground surface, it is not possible to make the distribution state of both the same due to the time difference between the time when pollutants started to diffuse and the time when the biological degradant was supplied. Have difficulty. 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. In particular, the conventional method does not provide a solution to the problem of different supply states in the unsaturated zone and the saturated aquifer.

Therefore, a method has been proposed in which a boring hole is provided and these microbial decomposition materials are injected from the hole. However, in the simple injection from the boring hole, the position, distribution range, concentration, etc. of the decomposition material are as designed. It is difficult to expect a supply of.

This is due to the heterogeneous nature of the soil layer, the supply to the water channel (water channel) formed by nature, and the drooling without knowing the excess or deficiency of the supplied material.

Therefore, an object of the present invention is to solve the above-mentioned problems in soil restoration, and to uniformly inject the decomposed material in the depth direction, inject it into a predetermined range on a line or on a plane, and to inject a predetermined amount. An object of the present invention is to provide a method for surely performing concentration injection, short-time injection, repeated injection, and injection of a plurality of materials.

[0020]

The above object can be achieved by the present invention described below.

That is, according to the present invention, an injection pipe capable of injecting a liquid material under pressure is provided at least at one or more locations on the surface of the soil / groundwater region contaminated with a halogenated hydrocarbon, and the hydrocarbon is introduced from this injection pipe. A method of injecting a liquid microbial material capable of decomposing urine under pressure and purifying contaminated soil and contaminated groundwater in situ with the hydrocarbon decomposing material, which is a multi-stage injection port with a valve that easily passes only to the discharge side. The outer pipe having the above is inserted into the soil, and the periphery thereof is filled with a filler that prevents the injectate from moving in the insertion direction of the outer wall of the pipe. The liquid microbial material is pressure-injected into the formation from the intended injection port through the inner pipe ejection port, and after the one-step injection is completed, the inner pipe is moved in the depth direction and sequentially added. By repeating the pressure injection process, liquid microbial material Is a method for cleaning contaminated soil and contaminated groundwater, which comprises injecting decomposing bacteria solution, nutrients, and microbial carrier simultaneously or individually, and liquid microbial decomposing material and gas (air Or gas) material is injected using the same injection pipe, and reinjection of liquid microbial decomposition material or gas is performed from an arbitrary injection port after a predetermined time has elapsed.

[0022]

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 problems occurred only when this groundwater was directly used in the groundwater downstream area, or when the groundwater spewed from the ground and outflowed to a 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 fouling mechanism of an organic chlorine solvent having a large specific gravity will be described.

FIG. 1 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 the 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 the solvent reaches the formation E (silty clay layer) where the solvent cannot sufficiently permeate or the aquifer in the dense soil layer, the solvent stays in the vicinity. Next, the rainwater or groundwater supplied from the ground establishes the adsorption equilibrium of the solvent between the soil and the water, and the solvent dissolves in the water with a constant distribution coefficient. In many cases, an organic chlorine solvent has a low solubility of several 1000 ppm or less. Although this number is physically low in terms of solubility, it is a large number for environmental pollution.

Furthermore, when the adsorption equilibrium of the pollutants to the soil and groundwater (keeping a constant value by the distribution coefficient) shifts to the re-equilibrium due to the newly inflowing / supplied groundwater, the dissolved solvent passes through the water. Expand pollution. 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 as compared with the loam layer and the silt layer. It will increase the expansion.

Further, the organic chlorine-based solvent that has penetrated into the ground evaporates in the ground along with the diffusion in a liquid state, and the ground air is polluted. This pollution often pollutes a wide area at a low concentration. Become.

An object of the present invention is to provide an effective pollution purification measure in a short time 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, complete purification of the entire contaminated area may be impractical.

In the present invention, it is an object of the present invention to carry out repair by microbiological purification (bioremediation) in a short time at an appropriate position and arrangement for the contamination mechanism of these aquifers and non-aquifers. .

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 halogenated hydrocarbons 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 rapidly decreases with time, as compared with the initial concentration at the time of spraying.

The reason for the decrease is not always clear, but it is considered to be due to competition with microorganisms existing in the soil, death from nutrition and other environmental incompatibility, predation by other organism groups such as protozoa, and the like.

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 grow in soil containing harmful substances and the activity is maintained. Similarly, in the case of enzymes, it is necessary to secure conditions for maintaining activity in soil. Therefore, when supplying these microorganisms into the ground, it is necessary to simultaneously supply the microbial active material, the survival material, the growth material and the like.

The object of the present invention is to supply the necessary amount of the materials required for the decomposition by the microorganisms collectively or sequentially, and to a desired place at an appropriate time interval.

When supplying the "necessary material" into the soil according to the present invention, an injection pipe having at least one multi-stage injection port is inserted into the "target place", and the target is obtained from this pipe. The required amount of material to be injected is injected only from the injection port of the depth, and then the same amount of material is injected from the injection ports of different depths to inject the required amount.

As a construction method in which these unit operations can be easily repeated, an apparatus similar to the cement or hardening agent injection apparatus used in the civil engineering work for hardening soft ground can be used. It has been found that microbial material can be supplied underground with a similar configuration.

The difference between the injection agent in civil engineering work and the injection of the microbial material in the present invention is that in the civil engineering work, the injection liquid is retained in a relatively limited area, and the injection material is introduced into the stratum so that the intended portion is hardened. On the other hand, in supplying the microbial material, it is often expected that the material penetrates into a wider area, and a material having a viscosity close to that of water is used. For this reason, restrictions on the injection pressure and time, that is, the injection amount are greatly different. In the civil engineering work for the purpose of hardening, there is a limitation to expect rapid hardening at the same time as injecting in a fluid state, but such a limitation does not occur for microbial materials. Also, in civil engineering work, the objective is achieved once curing is completed, but in the purification by microorganisms, there are demands to introduce multiple materials, especially materials with different physical properties such as liquid and gas, and injection is performed over several orders. May need to be repeated. Basically, the pipes and pumps used for injection are similar in configuration, but the configurations and materials for managing and operating each are different.

Next, the materials necessary for implantation will be described.

The microbial material for decomposing polluted chemical substances used in the present invention is a microbial material capable of decomposing chemical substances, and as a material to be added thereto, a material having a growth function necessary for the growth of microorganisms, An active maintenance functional material that exhibits decomposition and a survival functional material that serves as a carrier that allows microorganisms to enter the ground and stably inhabit are used. 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. In the present invention, the material necessary for producing this harmful substance-degrading enzyme is used as the activity maintaining material.

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

The surviving material is, in part, to provide a living space for protecting microorganisms when they are predated by other microorganisms and 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. It is also possible that the growth material, that is, the nutrient itself, fulfills this function.

As a material for providing a living space for microorganisms as a survival material, various microbial carriers which have been used in bioreactors conventionally known in the pharmaceutical industry, food industry, wastewater treatment system and the like are used. For example, porous glass, ceramics, metal oxides, activated carbon, kaolinite, bentonite, zeolite, silica gel, alumina, particulate carriers such as anthracite, starch, agar,
Chitin, chitosan, polyvinyl alcohol, alginic acid, polyacrylamide, carrageenan, agarose,
Gelatinous carrier such as gelatin, ion-exchange resinous cellulose,
There are ion exchange resins, 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. These have good adhesion of microorganisms,
Those having fine gaps are preferable. Further, a fine material that can easily penetrate at the time of injection is preferably used.

As the material that provides the habitation space and the material that also serves as the nutrient, many examples can be found in the compost material and the like known in the agriculture and forestry industry. That is, dried plant remains such as straw and sawdust of cereals such as straw, rice bran, okara, sugar cane squeezing residue, crabs and shrimp shells also have micropores and become degradable nutrients by microorganisms,
In particular, a material that can be processed into a fine particle size is used.

Next, concrete materials of the microorganism 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, Hanse
nula, Candida, Micrococcus,
Staphylococcus, Streptococ
cus, Leuconostoa, Lactobasi
llus, Corynebacterium, Arth
roberter, Bacillus, Clostri
aluminum, Neisseria, Escherichi
a, Enterobactor, Serratia, A
chromobacter, Alcaligenes,
Flavobacterium, Acetobacter
r, Nitrosomonas, Nitrobacte
r, Thiobacillus, Gluconbact
er, Pseudomonas, Xanthomona
s, Vibria.

As the growth material, those used in the medium for culturing microorganisms can be used. For example, broth medium, M9 medium, L medium, Maltextrac
t, MY medium, nitrifying bacteria selective medium and the like are effective.

As the activity-maintaining material, there are those 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. Examples of the inducer that can be identified include methane in methanotrophic bacteria, toluene, phenol, o-, m-, p-cresol and the like in aromatic bacterium, and ammonium salts in nitrifying bacteria. To date, more than a dozen species have been discovered and isolated, for example, what is known as a bacterium capable of degrading trichloroethane. 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 having methane monooxygenase.
sp. strain M (Agri. Biosci.
Biotech. Biochem. , 56, 486 (1
992), ibid. 56,736 (1992)), Methy.
losinus trichosporium OB
3b (Am. Chem. Soc. Natl. Meet.
Div. Environ. Chem. , 29, 365
(1989), Appl. biochem. Biote
chnol. , 28, 877 (1991), the latter of which is a case of Acinetobacter s having toluene monooxygenase or toluene dioxygenase.
p. strain G4 (Appl. Environ.
Microbiol. , 52,383 (1986), 53,949 (1987), 54,951 (198).
9), ibid. 56,279 (1990), ibid. 57,1935.
(1991)), Pseudomonas putid
a F1 (Appl. Environ. Microbi
ol. 54, 1703 (1988), 54, 257.
8 (1988)) is the representative. Of these,
Regarding an aromatic compound-assimilating trichloroethane (TCE) -degrading bacterium, the enzyme that decomposes TCE is an inducible enzyme that is induced by an aromatic compound such as phenol or toluene. Therefore, in order to decompose TCE in these microorganisms, As the material, a material containing an aromatic compound or being decomposed into an aromatic compound is used.

When an enzyme material is used, no growth material such as nutrients is required, but it is necessary to mix minerals necessary for the enzyme to exhibit activity, such as coenzymes such as Fe ²⁺ and NAPH. There is. In principle, an enzyme should have a permanent degrading effect if it exists in the system, but it is actually inactivated 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.

In the microbial decomposition material of the present invention, all or part of the above substances are used as an aqueous solution or suspension.

FIG. 2 is a sectional view of each unit of the injection pipe used in the present invention.

An outer injection tube 22 having a multistage injection port 23 used in the present invention is inserted into at least one of the contaminated areas 20, and the outer periphery of the outer tube 22 is surrounded by a filler 30. The inner pipe 21 having the ejection port 28 is inserted inside the outer pipe 22. Packers 29 are provided above and below the ejection port 28 of the inner tube 21 to prevent liquid or gas from moving to the adjacent injection port. The inner pipe 21 is connected to a flexible pipe 32 and an extendable connection pipe (not shown) so as to be movable up and down. The end of this pipe is connected to a liquid feed pump 24 or a compressor via a valve 25,
The liquid in the microorganism decomposing material tank 27 is sent, or a separate fluid is sent through the valve 26.

Each injection port is provided with a valve 33 that allows passage of the fluid at the ejection port only in the direction of sending it out. The outer pipe 22 is connected to each stage and has a structure in which the length can be appropriately changed according to the depth of the destination layer. The pitch of the inlet is arbitrarily set by changing the length of the pipe in one stage, but a pipe with a preset pitch is used. Usually 30 cm
A pitch of about 1 m is used. The injection is performed by arranging the jet port at the intended injection port position and then inflating the packer to seal the inner wall of the tube. For the expansion of the packer, a seal is obtained by sending the injecting fluid itself into the inside of the rubber-like body, or by separately providing a mechanism for sending the fluid for expanding the packer.

[0061]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 As a model test soil, a fine sand layer of 1.5 m, a Kanto loam layer of 1.5 m, Kanuma soil of 1 m, and Kuroboku soil of 0.5 m were laminated in a 5 m square concrete container, and the surface was kneaded and solidified. The clay layer was covered with about 20 cm. About 10 mg of trichlorethylene (TCE) is used in the fine sand layer, loam layer, and Kanuma soil layers.
It is adjusted to have a Kg contamination concentration. In addition, each stratum is pressure-welded at the time of stacking so that it has a permeability coefficient close to that of actual soil.

An excavation hole is provided in the center of the container as an injection well, and an outer tube having an outer diameter of 80 mm is inserted so that the tip is 25 cm from the bottom. The injection port of the outer tube was arranged in three stages of 0.5 m, 2.0 m, and 3.25 m from the bottom so as to be in the center of each layer, and each stage was provided with a hole having a diameter of 8 mm in four directions. A rubber tube smaller than the outer diameter of the outer tube was fitted into each injection port so as to close the injection port. The space between the drill hole and the outer pipe was sealed with a caking material containing a mixture of fine sand and water glass. The inner pipe having an outer diameter of 40 mm had a jet port at a position 20 mm from the tip, and rubber pipes serving as a packer were arranged above and below. The upper and lower sides of each rubber tube are closely fixed to the outer wall of the inner tube, and have a mechanism that expands from the central portion by the pressure of the injected fluid.

The opposite side of the inner pipe is connected to a rubber hose at the ground portion, and is further connected to a liquid feed pump via a valve. Each pipe is arranged so that the microbial decomposition material in the tank can be pressure-fed to the inlet by this liquid-feeding pump. The microbial degrading material is supplied to each layer from the bottom injection port under pressure to the fine sand layer, and then the injection port is 2.0 m in the loam layer.
It was moved to the vicinity of the injection port and pressure-injected, and similarly, it was supplied to Kanuma soil at the uppermost injection port.

The microbial decomposition material solution was prepared by culturing strain KK01 (deposited with the Institute of Microbial Industry, Institute of Industrial Science and Technology, Ministry of International Trade and Industry on March 11, 1992, deposit number FERM P-12869) in M9 medium to obtain a bacterial concentration of 10 ^A decomposition solution was prepared so as to have ⁸ pieces / ml, and edible red No. 106 was added thereto at a rate of 1 g / l as an indicator substance for confirming injection.

After the completion of the three injection cycles, the mixture was left for 2 days, half of the injected soil on the diagonal line was removed, and the distribution of the indicator substance and the distribution of microorganisms were observed. 20 to 50 cm maximum in the radial direction and approximately 4 in the radial direction
A distribution of 0 to 70 cm was observed, while in the Kanto loam layer, the distribution was 15 cm in the depth direction and 60 cm in the radial direction. When the TCE content ratio in the distribution region to the non-distribution region of the microbial degrading material was examined in each of these layers, it was confirmed that the TCE content ratio was attenuated to 1/3 to 1/7 in the distribution region.

Example 2 After the same injection as in Example 1, compressed air was supplied from each inlet to examine the distribution of microbial degradants and the decomposition of TCE. The distribution distances were depth direction and radius. It was confirmed that the increase was up to 50% from the same level in comparison with only the liquid microbial decomposing material in both directions, and that the decomposition was attenuated to 1/4 to 1/10.

Example 3 The same injection as in Example 1 was performed, and after standing for 2 days, the indicator substance was replaced with edible red No. 106 from blue No. 1 and reinjection was performed under the same conditions as in Example 1, and Distribution after 2 days and T
When the decomposition of CE was examined, the distribution was similar to that of the first injection, but the first injection distribution showed a slightly large tendency to diffuse in the direction of gravity. The TCE attenuation ratio at the place where the microbial decomposition liquid was supplied twice was 1/50 at the maximum and 1/2 at most.
It was 0 or less.

[0069]

EFFECTS OF THE INVENTION By using the method of the present invention, it becomes possible to supply a uniform, large amount and rapid microbial degrading material. In addition, one injection pipe can easily inject injection materials with different physical properties, it can be supplied economically and in a short time, and reinjection can be performed at an appropriate time. It became possible to easily manage the soil and to quickly and surely repair the target contaminated soil.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the spread of pollutants in a stratum.

FIG. 2 is a diagram for explaining the method of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazumi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. Soil contaminated with halogenated hydrocarbons
An injection pipe capable of injecting a liquid material under pressure is provided in at least one or more locations on the ground surface of the groundwater region, and a liquid microbial material capable of decomposing the hydrocarbon is injected under pressure from the injection pipe to obtain a hydrocarbon decomposing material. This is a method to purify contaminated soil and contaminated groundwater in-situ by inserting an outer pipe with a multi-stage inlet with a valve that can easily pass only to the discharge side into the soil, and in the surrounding direction in the direction of inserting the pipe outer wall. Filling a filler to prevent the injected material from moving, and inside the pipe, an inner pipe having an ejection port is sealed with a packer at the upper and lower injection ports, and the target injection port is inserted through the inner pipe ejection port. Liquid microbial material is injected into the formation under pressure, and after one-stage injection is completed, the inner tube is moved in the depth direction and the pressure injection process is repeated sequentially to supply the liquid microbial material to the contaminated formation. Purification of contaminated soil and contaminated groundwater characterized by Method. 2. The purification method according to claim 1, wherein the decomposing bacteria solution, the nutrient, and the microbial carrier are injected simultaneously or individually. 3. The purification method according to claim 1, wherein the liquid microbial decomposition material and the gas (air or gas) material are injected using the same injection pipe. 4. The purification method according to claim 1, wherein after a lapse of a predetermined time, reinjection of the liquid microbial decomposition material or gas is performed from an arbitrary inlet.