JP4835486B2 - Soil and groundwater purification methods - Google Patents

Description

  The present invention relates to a method for purifying soil and groundwater contaminated with volatile organochlorine compounds by microorganisms.

  There are two methods of purifying contaminated soil and groundwater using microorganisms: biostimulation and biougulation. The former biostimulation is the injection of nutrients that activate microorganisms that decompose volatile organochlorine compounds among the microorganisms that grow naturally in soil and groundwater contaminated areas contaminated by volatile organochlorine compounds, By the action of the microorganisms, the volatile organic chlorine compound is reduced in molecular weight and finally detoxified.

  In addition, the latter bio-augmentation introduces microorganisms that decompose volatile organochlorine compounds from the outside into soil and groundwater contaminated areas contaminated by volatile organochlorine compounds, and promotes purification of pollution. .

  However, there are many methods for decomposing volatile organochlorine compounds in soil and groundwater contaminated areas contaminated with volatile organochlorine compounds using biostimulation and bio-amulation, but most of them are listed. In many cases, the molecular weight of dichloroethylene and dichloromethane remains low, and the impact of dichloroethylene and dichloromethane on the human body (possibility of carcinogenicity) is the highest compared to tetrachloroethylene and trichloroethylene, and the molecular weight of dichloroethylene and dichloromethane is reduced. Many microorganisms have not been discovered.

And since such a biofilm processes the organic substance in waste_water | drain efficiently, since BOD volumetric load is about 5 times the activated sludge method, it is a very efficient waste-water treatment method. However, the biofilm treatment method was originally an advantageous treatment method for drainage with a low BOD and a large amount of water, and was used for tertiary treatment. Then, the past few years come, in recent years, began to BOD volume load begins also used to focusing on the high points in the primary processing and secondary processing. In addition, a rotating contact aeration method, an anaerobic immersion filter bed, a sprinkling water filter bed, and the like are also processing methods having a high BOD volume load.

Regarding microorganisms that lower the molecular weight of dichloroethylene and dichloromethane, Dehalococides ethenogenes 195 strain is known as an anaerobic microorganism, and includes a group of useful microorganisms composed of a plurality of types of microorganisms such as this microorganism and a nutrient salt of the group of useful microorganisms. It has been proposed to create a microbial treatment layer containing a substrate that assists the propagation of useful microbial groups (see Patent Document 1 below).
JP-A-11-333493

  However, volatile organochlorine compounds are reduced in molecular weight and harmless by the food chain such as microorganisms of useful microorganisms composed of multiple types of microorganisms (eg photosynthetic bacteria, yeast, lactic acid bacteria, actinomycetes, filamentous fungi, etc.) In order to determine whether or not microorganisms to be activated are active, it is necessary to sample contaminated soil and groundwater to confirm that chlorine is decomposed from volatile organochlorine compounds. This confirmation work takes time and complexity such as identification of microorganisms that decompose volatile organic chlorine compounds and time-series changes of volatile organic chlorine compounds.

  Moreover, even if PCE (tetrachloroethylene) and TCE (trichloroethylene) which are volatile organic chlorine compounds are decomposed, cis-DCE which is one of volatile organic chlorine compounds cannot be decomposed.

  Therefore, the problem to be solved by the present invention is that Clostridium sp. KD13 (patentridium sp. KD13 (patent biological deposit center accession number: FERM P-21115)) is a volatile organic chlorine compound (especially cis-DCE = cis-dichloroethylene). In order to lower the molecular weight, a purification wall using microorganisms that purify volatile organic chlorine compounds that are pollutants is constructed on the downstream side of the underground number that flows in the contaminated area, and Clostridium species KD13 (anaerobic microorganisms) Clostridium sp.KD13 (patent biological deposit center accession number: FERM P-21115) is activated to provide a treatment method in which a volatile organochlorine compound is reduced in molecular weight and rendered harmless.

As a result of the inventor's earnest studies on the above-mentioned problems, the method for purifying soil and groundwater according to the first invention of the present application relates to soil and groundwater contaminated with volatile organochlorine compounds, anaerobic microorganisms having spores, and A method for purification treatment by a nutrient source of the anaerobic microorganisms having spores, wherein a wall for purifying the volatile organochlorine compound is constructed downstream of the flow of groundwater in a contaminated area, and the wall is a microorganism A purification wall and a nutrient purification wall are configured, and the microorganism purification wall is made to spore the anaerobic microorganism having the spore, and then sealed with nitrogen gas in a biodegradable container, the nutrient purification wall is Solid glucose is filled in a biodegradable container, and the anaerobic microorganism is at least Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number). No .: FERM P-21115), on the upstream side of the groundwater flow in the contaminated area, an injection well reaching the bottom of the permeable layer in the lower soil is provided, and the wall is provided to a position reaching the lower permeable layer in the lower soil, the pumping wells provided on the downstream side of the groundwater of the wall, and storing the ground water that is pumped from the pumping wells, allowed to flow into nutrient to stimulate the anaerobic microorganism with spores present in the ground water in savings Tomeso A culture step of growing the anaerobic microorganisms having spores by a heating means provided in the storage tank; and re-injecting the anaerobic microorganisms having spores grown in the culture step together with a culture solution into the injection well The process of making it repeat is made to repeat.

  By this method, anaerobic microorganisms with spores can be grown and activated by nutrient sources applied to the anaerobic microorganisms, and contaminants from soil and groundwater contaminated with volatile organochlorine compounds are purified. can do.

  And Clostridium sp. KD13 (Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) is a volatile organic chlorine compound PCE (tetrachloroethylene), TCE (trichloroethylene), cis-DCE (cis-dichloroethylene) It is decomposed by taking nutrients into the body, etc., and releases acetic acid, butyric acid, and chloride ions as metabolites.The released acetic acid and butyric acid can be used as part of the nutrient source of other anaerobic microorganisms. .

That is, the degradation pathway of volatile organochlorine compounds of Dehalococides ethenogenes 195, which removes chlorine one by one, is such that, for example, PCE → TCE → cis-DCE → VC → ethylene, chlorine is replaced with hydrogen one by one. As described above , Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) shows different degradation pathways as described above .
In addition, this method purifies Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) sealed with nitrogen gas in a biodegradable container up to the position where the groundwater such as the gravel layer flows. It can be arranged as a wall, and volatile organochlorine compounds can be reduced in molecular weight or detoxified by this purification wall. Although the temperature of groundwater varies depending on the location, it is an average of around 18 ° C., and as long as there is a nutrient source, it is an environment where the spore-like clostridium species KD13 can sufficiently germinate.
In addition, this purification wall is arranged so as to be substantially perpendicular to the flow of groundwater, and the groundwater that has passed through the contaminated area passes through this purification wall by a water shielding wall such as a sheet pile, It is unlikely that volatile organochlorine compounds, which are pollutants, will come out of the impermeable walls due to the concentration of groundwater. By increasing the thickness of the purification wall, pollutants and Clostridium species KD13 (patent biological deposit center accession number) : FERM P-21115) can be promoted by increasing the chance of contact.
In this case, germination of Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) can be delayed by time difference by enclosing in a biodegradable container in a spore state, and germinates and activates. Clostridium species KD13 can remain in place. The biodegradable container is made of starch or a polylactic acid ester as a main component, so that the container also becomes a nutrient source for Clostridium species KD13.
Furthermore, by this method, solid glucose enclosed in a biodegradable container can be arranged as a purification wall up to the position where the groundwater such as the gravel layer flows, and the volatile organic chlorine compound is purified. Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) is activated by ingesting the wall as a nutrient source, and volatile organochlorine compounds that are pollutants can be decomposed and reduced in molecular weight.
As for the arrangement of the purification walls, the purification walls of Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) enclosed in a biodegradable container together with nitrogen gas are enclosed in a biodegradable container. The solid glucose purification walls are alternately arranged in a staggered manner so as to be substantially perpendicular to the groundwater flow, or a biodegradable container in the previous stage so as to be substantially perpendicular to the groundwater flow. Purified wall of Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) enclosed with nitrogen gas in the wall, and the solid wall of purified glucose sealed in a biodegradable container at the subsequent stage Depending on the speed of groundwater flow and the concentration of pollutant volatile organochlorine compounds in the groundwater The method can be selected.

Moreover, the soil and groundwater purification method according to the second invention of the present application volatilizes cis-DCE (cis-dichloroethylene), which is one kind of volatile organochlorine compound, by a heating means in the culture process in the storage tank. It is characterized by this.

  By this method, contaminated groundwater pumped from the pumping well is temporarily stored in a storage tank, and by heating the groundwater stored in this storage tank, the cis-DCE that was eluted into the groundwater and could not be purified. (Cis-dichloroethylene) can be volatilized.

  Moreover, by heating the groundwater stored in the storage tank, the DO (dissolved oxygen amount) in the groundwater is also reduced, and an anaerobic atmosphere can be created, whereby Clostridium sp. KD13 (patient organism sp. KD13 (patented organism). Deposit center accession number: FERM P-21115) can be activated.

Further, in the soil and groundwater purification method according to the third invention of the present application, the heating means of the storage tank is a seed heater, and the temperature of the groundwater in the storage tank is 32 ° C. to 37 ° C. due to the heating of the sheath heater. The nutrient source is supplied from the nutrient source supply tank to the storage tank so as to activate and proliferate the anaerobic microorganisms having spores.

  By this method, the temperature of the groundwater is adjusted from 32 ° C. to 37 ° C. by the sheath heater provided in the storage tank, and the nutrient source is supplied from the nutrient source supply tank, so that Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) can be activated and propagated.

Similarly to the second invention of the present application, since the temperature of the groundwater is adjusted from 32 ° C. to 37 ° C., cis-DCE (cis-dichloroethylene) that has been eluted into the groundwater and cannot be purified is volatilized. be able to.

The soil and groundwater purification method according to the fourth invention of the present application is characterized in that the nutrient source supplied to the storage tank is an aqueous solution in which glucose is dissolved as a main component.

  By this method, Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) in the culture tank can be propagated by a nutrient source.

The percentage of this nutrient source is glucose 52%, asparagine-hydrate 25% K ₂ HPO ₄ 15%, KH ₂ PO ₄ 4%, MgSO ₄ 1%, other salts 3%, and affinity with groundwater Therefore, the glucose is preferably liquid.

Further, the soil and groundwater purification method according to the fifth invention of the present application is such that the structure of the purification wall is a double cylindrical shape, and solid glucose is spread on the outside with a biodegradable container, on the inside. It is characterized by laying a biodegradable container with anaerobic microorganisms in the spore state.

  This method is particularly suitable for the purification of soil and groundwater in places where the flow of groundwater is fast and where the influence of seawater (changes in groundwater level due to tides) occurs.

Further, the soil and groundwater purification method according to the sixth invention of the present application is such that the structure of the purification wall is a double cylindrical shape, and solid glucose is spread on the inside with a biodegradable container and on the outside. It is characterized by laying a biodegradable container with anaerobic microorganisms in the spore state.

  This method is particularly suitable for the purification of soil and groundwater in places where the flow of groundwater is fast and where the influence of seawater (changes in groundwater level due to tides) occurs.

Further, regarding the arrangement of the purification walls, the purification according to the fifth aspect of the present invention has a configuration in which solid glucose is spread on a biodegradable container and a spore-like anaerobic microorganism is spread on the inside with a biodegradable container. A purification wall having a structure in which a biodegradable container is spread with a solid glucose on the inside and a biodegradable container on the outside with a biodegradable container on the outside, which is the invention of the sixth invention of the present application, Alternatingly arranged in a staggered manner so as to be substantially perpendicular to the flow of groundwater, or solid glucose is produced on the outside of the fifth invention of the present application so as to be substantially perpendicular to the flow of groundwater. A degradable container is laid down, a spore-like anaerobic microorganism is laid on the inside, and a purification wall is laid down with a biodegradable container, and then solid glucose is biodegraded on the inside of the invention of the present application 6 in the subsequent stage. Lay a container of sex, on the outside The anaerobic microorganisms child states have placed way to pack laid purification wall structure paved containers biodegradable, can select the alignment method in accordance with the appropriate contaminated.

  According to the present invention, soil and groundwater contaminated with volatile organic chlorine compounds can be detoxified by decomposing and purifying cis-DCE, which is one of volatile organic chlorine compounds, by anaerobic microorganisms having spores. .

  In this purification treatment, groundwater is shielded with a sheet pile or the like on the downstream side of the groundwater in the contaminated area, and the purification wall of Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) and solid glucose are the main components. By passing through the purification wall, it is possible to decompose, purify and detoxify cis-DCE which is one of volatile organic chlorine compounds.

  In addition, germination of anaerobic microorganisms (Clostridial species KD13 (patent biological deposit center accession number: FERM P-21115)) having spores can promote the activity and proliferation of the microorganisms.

The invention according to claim 1 is a method for purifying soil and groundwater contaminated with volatile organochlorine compounds with anaerobic microorganisms having spores and nutrients of the anaerobic microorganisms having spores, A wall for purifying the volatile organochlorine compound is constructed on the downstream side of the flow of groundwater in the region, and the wall is configured using a microbial purification wall and a nutrient source purification wall, and the microbial purification wall is the spore. Anaerobic microorganisms having a spore state are sealed with nitrogen gas in a biodegradable container, the nutrient purification wall fills the biodegradable container with solid glucose, and the anaerobic microorganisms are at least Clostridium sp. KD13 (patient biological deposit center accession number: FERM P-21115), upstream of the flow of groundwater in the contaminated area The injection well that reaches the bottom of the permeable layer at the bottom of the soil, the wall is provided up to the position reaching the bottom of the permeable layer at the bottom of the soil, the pumping well is provided on the downstream side of the groundwater of the wall, and the water pumped from the pumping well growth groundwater were pooled nutrients to stimulate the anaerobic microorganism with spores present in the ground water to flow into the savings Tomeso, the anaerobic microorganism with spores by heating means which is provided in the reservoir And the step of reinjecting the anaerobic microorganisms having the spore grown in the culture step together with the culture solution into the injection well.

  As a result, anaerobic microorganisms with spores can be grown and activated by nutrient sources applied to the anaerobic microorganisms, and contaminants from soil and groundwater contaminated with volatile organochlorine compounds can be purified. it can.

  Also, a part of the piping that flows into the storage tank is branched, a part of the groundwater is extracted, and the presence or absence of volatile organic chlorine compounds (for example, PCE, TCE, cis-DCE, etc.) and the chloride ion concentration are measured by liquid chromatography. It can measure and confirm the progress of purification.

The anaerobic microorganism is at least Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115), and is characterized by volatility represented by Dehalococides ethenogenes 195 strain. Similar to the obligate anaerobic microorganism that lowers the molecular weight and detoxifies the organic chlorine compound, the volatile organic chlorine compound can be reduced in molecular weight and detoxified.
In addition, by this method, Clostridium species KD13 (patent biological deposit center accession number: FERM P-) encapsulated with nitrogen gas in a biodegradable container until reaching the formation (permeable layer) through which groundwater such as gravel layer flows. 21115) can be arranged as a purification wall, and volatile organic chlorine compounds can be reduced in molecular weight or detoxified by this purification wall. Although the temperature of groundwater varies depending on the location, it is an average of around 18 ° C., and as long as there is a nutrient source, it is an environment where the spore-like clostridium species KD13 can sufficiently germinate.
In addition, this purification wall is arranged so as to be substantially perpendicular to the flow of groundwater, and the groundwater that has passed through the contaminated area passes through this purification wall by a water shielding wall such as a sheet pile, It is unlikely that volatile organochlorine compounds, which are pollutants, will come out of the impermeable walls due to the concentration of groundwater. By increasing the thickness of the purification wall, pollutants and Clostridium species KD13 (patent biological deposit center accession number) : FERM P-21115) can be promoted by increasing the chance of contact.
In this case, germination of Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) can be delayed by time difference by enclosing in a biodegradable container in a spore state, and germinates and activates. Clostridium species KD13 can remain in place. The biodegradable container is made of starch or a polylactic acid ester as a main component, so that the container also becomes a nutrient source for Clostridium species KD13.
In addition, by this method, solid glucose enclosed in a biodegradable container can be placed as a purification wall up to a position where the groundwater such as a gravel layer flows (permeable layer). This purification wall is activated by ingestion of this purification wall as a nutrient source by Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115), and volatile organic chlorine compounds that are pollutants can be decomposed and reduced in molecular weight. .
Further, a product obtained by impregnating activated carbon with glucose as a nutrient source and drying it may be used as a purification wall. In this case, the pores of the activated carbon are preferably 20 μm or more. This is because Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) has an overall length of about 10 μm when activated and can be supported on activated carbon.

Further, the invention according to claim 2, in addition to the characteristics of the invention according to claim 1, in the culture step in reservoir, heating means, which is a kind of volatile organic chlorine compounds cis-DCE ( Cis-dichloroethylene) is volatilized.

  By this method, contaminated groundwater pumped from the pumping well is temporarily stored in a storage tank, and by heating the groundwater stored in this storage tank, the cis-DCE that was eluted into the groundwater and could not be purified. (Cis-dichloroethylene) can be volatilized.

  Moreover, by heating the groundwater stored in the storage tank, the DO (dissolved oxygen amount) in the groundwater is also reduced, and an anaerobic atmosphere can be created, whereby Clostridium sp. KD13 (patient organism sp. KD13 (patented organism). Deposit center accession number: FERM P-21115) can be activated.

Further, an invention according to claim 3, in addition to the characteristics of the invention described in claim 1, a sheathed heater heating means reservoir, the heating of the sheath heater of the groundwater in said reservoir The temperature is adjusted from 32 ° C. to 37 ° C., and a nutrient source is supplied from the nutrient source supply tank to the storage tank so as to activate and grow anaerobic microorganisms having spores.

  By this method, the temperature of the groundwater is adjusted from 32 ° C. to 37 ° C. by the sheath heater provided in the storage tank, and the nutrient source is supplied from the nutrient source supply tank, so that Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) can be activated and propagated.

  As a result, Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115), which is an obligate anaerobic microorganism, can be grown at a temperature suitable for growth with respect to this growth 25. It can be activated and propagated by culturing in a storage tank supplied with a nutrient source at 37 ° C. to 37 ° C. (the most suitable temperature was 34 ° C. from the culture experiment).

The invention described in claim 4 is characterized in that, in addition to the features of the invention described in claim 1 or claim 3 , the nutrient source supplied to the storage tank is mainly composed of an aqueous solution in which glucose is dissolved. It is a thing.

  By this method, Clostridium species KD13 (patent biological deposit center accession number: FERM P-21115) in the storage tank can be propagated by a nutrient source.

Moreover, the ratio of this nutrient source is glucose 52%, asparagine-hydrate 25% K ₂ HPO ₄ 15%, KH ₂ PO ₄ 4%, MgSO ₄ 1%, and other salts 3%. In view of affinity, the glucose in the reservoir is preferably liquid.

  Furthermore, sucrose or waste sugar can be used as an alternative to glucose, which is the main component of this nutrient source.

By this nutrient source, Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115) can be activated and propagated.

In addition to the features of the invention described in claim 1, the invention described in claim 5 is such that the purification wall has a double cylindrical shape, and solid glucose is biodegradable on the outside. And a biodegradable container with spore-like anaerobic microorganisms.

  This method is particularly suitable for the purification of soil and groundwater in places where the flow of groundwater is fast and where the influence of seawater (changes in groundwater level due to tides) occurs.

  Also, when the purification wall has a double cylindrical shape, a hole with a diameter of 30 cm is first provided up to the bottom of the gravel layer, a tube with a diameter of 10 cm is installed at the center, and a solid shape is first placed outside the tube. A method in which a biodegradable container filled with glucose is laid, then a spore-like anaerobic microorganism is laid in a biodegradable container with nitrogen, and the tube is finally blown off. Alternatively, a net-like cylinder may be used, and the net-like cylinder may be a member constituting the purification wall.

In addition to the features of the invention of the first aspect, the invention described in claim 6 is a double cylindrical structure of the purification wall, and a solid-degradable container is provided inside with a biodegradable container. The spore-like anaerobic microorganism is spread on the outside, and a biodegradable container is laid on the outside.

  This method is particularly suitable for the purification of soil and groundwater in places where the flow of groundwater is fast and where the influence of seawater (changes in groundwater level due to tides) occurs.

Further, regarding the arrangement of the purification walls, the purification according to the fifth aspect of the present invention has a configuration in which solid glucose is spread on a biodegradable container and a spore-like anaerobic microorganism is spread on the inside with a biodegradable container. A purification wall having a structure in which a biodegradable container is spread with a solid glucose on the inside and a biodegradable container on the outside with a biodegradable container on the outside, which is the invention of the sixth invention of the present application, Alternatingly arranged in a staggered manner so as to be substantially perpendicular to the flow of groundwater, or solid glucose is produced on the outside of the fifth invention of the present application so as to be substantially perpendicular to the flow of groundwater. A degradable container is laid down, a spore-like anaerobic microorganism is laid on the inside, and a purification wall is laid down with a biodegradable container, and then solid glucose is biodegraded on the inside of the invention of the present application 6 in the subsequent stage. Lay a container of sex, on the outside The anaerobic microorganisms child states have placed way to pack laid purification wall structure paved containers biodegradable, can select the alignment method in accordance with the appropriate contaminated.

  The present invention will be described with reference to FIGS. FIG. 1 is a schematic view of the purification treatment method of the present invention. FIG. 2 is a schematic view showing a plane of the purification treatment method of the present invention.

  Volatile organochlorine compounds, which are pollutants, have been used frequently in the past for cleaning electronic components, but recently, volatile organochlorine compounds with concentrations exceeding environmental standards have been detected in soil and groundwater. became.

  The soil contaminated with this volatile organic chlorine compound is detected from the underground of the factory currently in operation or the factory site 1 used in the past, and for example, excavation method, metal reducing agent injection method for the contamination purification work. It is carried out by the microbiological purification method.

  In the present invention, when purifying soil and groundwater contaminated with volatile organochlorine compounds, an attempt was made to purify bio-ugulation using microorganisms with a purification wall.

As shown in FIG. 1, it was a purification work on the factory site 1, the area of the factory site 1 was about 20000 m ² , and the contaminated area 2 was 1500 m ² .

  After investigating materials, etc., it was tested whether bio-augmentation was possible.

  The soil / groundwater contaminated area 2 contaminated with the volatile organochlorine compound in the factory site 1 reaches the permeable layer 3 through which the groundwater flows.

  An injection well 4 having a diameter of 100 mm drilled from the surface layer to the bottom of the permeable layer 3 such as gravel is provided on the upstream side of the groundwater correlated with the contaminated area 2, and the downstream of the groundwater facing the contaminated area 2 when viewed from the injection well 4. A purification wall 5 was provided at the side position, and a pumping well 6 was provided downstream thereof. The injection well 4 may be provided at a position where the concentration of the volatile organic chlorine compound in the contaminated region 2 is highest.

  From the injection well 4, groundwater pumped by a pump 7 from a pumping well 6 provided on the ground is supplied to the storage tank 8. A nutrient source supply tank 9 is communicated with the storage tank 8 through a pipe, and a liquid nutrient source mainly composed of glucose is appropriately supplied to the storage tank 8.

This nutrient source promotes the activation of Clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115), which is an obligate anaerobic microorganism. 50%, asparagine-hydrate 25% K ₂ HPO ₄ 15%, KH ₂ PO ₄ 4%, MgSO ₄ 2%, other salts 4% Sucrose and waste sugar can also be used.

Further, in the culture at the laboratory level, in the temperature control at 34 ° C., the nutrient ratio is 52% glucose, 25% asparagine hydrate 15% K ₂ HPO _{4, 4} % KH ₂ PO ₄ , MgSO ₄ The growth rate was the fastest when 1% and other salts 3%.

  The storage tank 8 is provided with a sheathed heater 10 as a heating means, and the temperature of the solution in the storage tank 8 can be controlled from 32 ° C. to 37 ° C. which is a temperature suitable for growth. Although not shown, a thermistor is provided and the temperature is adjusted by the thermistor.

  After about 20 minutes have elapsed after the temperature of the solution in the storage tank 8 has been adjusted from 32 ° C. to 37 ° C., the control valve 11 at the bottom of the storage tank 8 opens, and the solution inside the storage tank 8 is injected into the injection well 4. The

  The thermistor signal provided in the storage tank 8 and the control valve 11 are linked by a control device (not shown), and a timer is also provided in the control device.

  The solution in the storage tank 8 injected into the injection well 4 is dissolved in the groundwater of the permeable layer 3 and diffused according to the groundwater flow.

  This solution is a liquid nutrient source mainly composed of glucose, and in particular, promotes the activation of Clostridium sp. KD13 (clostridium sp. KD13 (patent biological deposit center accession number: FERM P-21115). .

  The diffused solution also comes into contact with the contaminated area 2 and can reduce the molecular weight of volatile chlorinated organic compounds, particularly cis-DCE (cis-dichloroethylene), by the action of obligate anaerobic microorganisms.

  Moreover, the volatile organic chlorine compound which is a pollutant is eluted into the permeable layer such as gravel from the surface water tank or the difficult tank water layer such as silt by the rainwater or the like, and is diffused by the groundwater flow.

  Volatile organochlorine compounds diffused by this groundwater flow are decomposed by obligate anaerobic microorganisms in the soil, but most currently known obligate anaerobic microorganisms are, for example, PCE (tetrachloroethylene) → cis. -Decomposition reaction is stopped by cis-DCE, such as DCE, TCE (trichloroethylene) → cis-DCE

  In order to make the cis-DCE low-molecular or harmless, a purification wall 5 is provided on the downstream side of the contaminated region 2, and one of the purification walls 5 is a spore-shaped clostridium sp. Biological Deposit Center Accession Number: FERM P-21115) sealed with nitrogen gas in a container mainly composed of biodegradable polylactic acid ester (hereinafter referred to as microbial purification wall 5a), and other purification walls 5, a solid glucose sealed in a biodegradable container (hereinafter referred to as a nutrient source purification wall 5b) is arranged so as to be substantially orthogonal to the groundwater flow, and the volatilization that is a contaminant in the contaminated area 2 A sheet pile 12 that is guided so as to come into contact with the volatile organic chlorine compound is provided in parallel with the groundwater flow, and a volatile organic chlorine compound (particularly c) that is a contaminant on the purification wall 5 is-DCE) was arranged so that it could be depolymerized or rendered harmless.

  Clostridium species KD13, an obligate anaerobic microorganism, ingests volatile organochlorine compounds and releases chloride ions as metabolites thereof. Other metabolites include butyric acid, acetic acid, and carbon dioxide. Of these, butyric acid and acetic acid, which decompose glucose in the body and are released as metabolites, become part of the nutrient source of other anaerobic microorganisms, and can promote purification.

  Thus, the volatile organochlorine compounds (PCE, TCE, cis-DCE, VC) eluted from the surface layer into the groundwater of the permeable layer 3 are reduced in molecular weight or detoxified by the purification wall 5.

  As a result of observing purification using the present invention in time series, PCE and TCE, which are volatile organochlorine compounds, are below the environmental standard value in about 80 days, and cis-DCE is also below the environmental standard value in 120 days. became.

  However, volatile organochlorine compounds may not come into contact with obligate anaerobic microorganisms depending on the direction of groundwater flow, groundwater level (level difference), and a pumping well 6 is provided downstream of the purification wall 5 to provide groundwater. Pump up the water. The temperature of the pumped ground water was 17.4 ° C.

  The pumped-up groundwater is stored in a storage tank 8, a part of the groundwater is extracted from a branch pipe (not shown) immediately before being supplied to the storage tank 8, and the concentration of eluted chloride ions is measured by liquid chromatography. In particular, Clostridium sp. KD13 ingests volatile organochlorine compounds (PCE, TCE, cis-DCE, VC) into the body to determine the state of promoting the low molecular weight of volatile organochlorine compounds. Can do.

  Further, even if cis-DCE which is a volatile organic chlorine compound remains in the groundwater stored in the storage tank 8, it can be volatilized by heating the groundwater in the sheathed heater 10 provided in the storage tank 8. .

  In the above, the purification method of cis-DCE, which is a volatile organic chlorine compound, and the mechanism of microorganisms used therefor have been described. However, this is only an example of the present invention, and the presence of contaminated soil such as the arrangement of the purification wall and the injection amount. The same applies to the form of purifying volatile organochlorine compounds by a construction method suitable for the site.

  Needless to say, the arrangement of the purification walls in which the microorganism purification wall 5a and the nutrient source purification wall 5b are provided in one well.

Schematic of the purification treatment method of the present invention Schematic plan view of the purification treatment method of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Factory site 2 Polluted area 3 Permeable layer 4 Injection well 5 Purification wall 5a Microbial purification wall 5b Nutrient source purification wall 6 Pumping well 7 Pumping pump 8 Reservoir tank 9 Nutrient source supply tank 10 Sheath heater 11 Control valve 12 Sheet pile

Claims (6)

A method of purifying soil and groundwater contaminated with volatile organochlorine compounds with anaerobic microorganisms having spores and nutrient sources of said anaerobic microorganisms having spores, on the downstream side of the groundwater flow in the contaminated area Constructing a wall for purifying the volatile organochlorine compound, the wall comprising a microbial purification wall and a nutrient source purification wall, the microbial purification wall in the spore state anaerobic microorganisms having the spore Then, the biodegradable container is filled with nitrogen gas, the nutrient source purification wall is filled with solid glucose in the biodegradable container, and the anaerobic microorganism is at least Clostridium sp.KD13 (clostridium sp. KD13). (Patent biological deposit center accession number: FERM P-21115), on the upstream side of the groundwater flow in the contaminated area, below the permeable layer below the soil An injection well is provided, the wall is provided up to a position reaching the bottom of the permeable layer below the soil, a pumping well is provided on the downstream side of the groundwater on the wall, the groundwater pumped from the pumping well is stored, and the groundwater is stored in the groundwater. the anaerobic microorganisms nutrient source for activity flowed into savings Tomeso, the culturing step for growing the anaerobic microorganism with spores by heating means which is provided in the storage tank, the culturing step with spores that are present A method for purifying soil and groundwater, characterized by repeating the step of reinjecting the anaerobic microorganisms having spores grown in step 1 with the culture solution into the injection well. The method for purifying soil and groundwater according to claim 1, wherein in the culturing step, cis-DCE (cis-dichloroethylene), which is one of the volatile organochlorine compounds, is volatilized by the heating means. The heating means of the storage tank is a sheathed heater, and the temperature of the groundwater in the storage tank is adjusted from 32 ° C. to 37 ° C. by the heating of the sheathed heater, and the anaerobic microorganisms having the spores are activated and propagated. The method for purifying soil and groundwater according to claim 1, wherein a nutrient source is supplied to the storage tank from a nutrient source supply tank. The method for purifying soil and groundwater according to claim 1 or 3, wherein the nutrient source supplied to the reservoir is an aqueous solution in which glucose is dissolved. The wall structure is a double cylinder, the solid tube is spread with a biodegradable container on the outer cylinder side, and the spore-like anaerobic microorganism is spread on the inner cylinder side with a biodegradable container. The soil and groundwater purification method according to claim 1. The wall has a double cylindrical shape, and a solid biodegradable container is spread on the inner cylinder side, and a spore-like anaerobic microorganism is spread on the outer cylinder side. The soil and groundwater purification method according to claim 1.

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