JP2005262107A - Method for cleaning matter contaminated with organochlorine compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for efficiently removing an organochlorine compound from the matter to be treated such as soil at a high biological utilization rate when the matter contaminated with the organochlorine compound such as dioxins is cleaned by the action of a microbe. <P>SOLUTION: This method for cleaning the matter contaminated with the organochlorine compound comprises the steps of: adding a sustained-release base material containing oil, fat and/or a surfactant to the matter which is to be treated and is contaminated with the organochlorine compound; removing the organochlorine compound by releasing the oil, fat and/or surfactant from the sustained-release base material; and decomposing the removed organochlorine compound by the action of the microbe. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for purifying a substance contaminated with an organic chlorine compound, and more specifically, an organic chlorine compound for purifying a substance such as soil or ash contaminated with an organic chlorine compound such as dioxins by the action of microorganisms. It is related with the purification method of the substance polluted by.

In contaminated soil, the main factor limiting the rate of biodegradation of pollutants such as dioxins is thought to be that there is less movement of pollutants in the soil than the resolution of microorganisms themselves. Yes.
That is, the hydrophobic pollutant is strongly adsorbed to the soil, so that it is difficult to be taken up by microorganisms and biological degradation is difficult to proceed.

  For this reason, in the biological purification of soil contaminated with organochlorine compounds, the present inventors have made it easy to elute the organochlorine compounds adsorbed on the soil with oils and fats and to make them easily incorporated into microorganisms. A method was proposed (Japanese Patent Application No. 2003-157071).

  In addition, a method for increasing the bioavailability of pollutants against microorganisms having a pollutant resolution by using an aqueous solution of cyclodextrins or their derivatives has been proposed (for example, Patent Document 1 and Patent Document 2).

JP-A-7-946 JP 2002-210432 A

  The method of adding fats and oils (Japanese Patent Application No. 2003-157071) is an excellent method for the purpose of eluting organochlorine compounds such as dioxins and improving the biological degradation rate. There is an aspect that control becomes difficult, and there is still room for improvement. In addition, since the added surfactant or oil or fat sometimes covers the surface of the soil particles that have adsorbed the microorganisms and contaminants, there is an aspect in which a state in which contact between the microorganisms and the contaminants is prevented occurs.

  The methods of adding the cyclodextrins (Patent Document 1 and Patent Document 2) have a limitation in the sustained action, and the desired effect cannot be achieved unless the cyclodextrins are periodically added. It was.

  Therefore, when purifying substances contaminated with organochlorine compounds such as dioxins by the action of microorganisms, technology that can efficiently desorb organochlorine compounds from treated substances such as soil and increase the biological utilization rate The offer of was desired.

  In order to solve the above-mentioned problems, a first aspect of the present invention is to add and mix a sustained-release base material containing fats and oils and / or a surfactant to a substance to be treated contaminated with an organic chlorine compound, and Release fats and / or surfactants from a release substrate to desorb or elute organochlorine compounds in the material to be treated, and decompose the desorbed or eluted organochlorine compounds by the action of microorganisms This is a purification method for substances contaminated with organochlorine compounds.

In this method for decomposing organochlorine compounds, by adding a sustained-release base material, the fats and / or surfactants contained therein are gradually released, and the organochlorine compounds in the substance to be treated are gradually added in small amounts. Can be eluted. As a result, there are the following advantages.
The organic chlorine compound adsorbed on the substance to be treated is desorbed or eluted by the action of the oil or the surfactant and is easily used by microorganisms, so that the purification efficiency is improved.
Also, by slowly releasing oils and fats and surfactants, there is no adverse effect that it becomes difficult to adjust the moisture content as in the case of adding at once, and there is also an adverse effect that prevents the contact between microorganisms and contaminants. Absent.
Furthermore, unlike chemical purification methods, biological purification by microorganisms requires a relatively long period of time for decomposition, so organic chlorine compounds are desorbed little by little according to the growth cycle of microorganisms. Is effective, and the sustained-release substrate of the present invention meets this purpose.

  According to a second aspect of the present invention, in the first aspect, an organic group containing an anaerobic microorganism and an aerobic microorganism is added to the substance to be treated together with the sustained-release substrate. This is a purification method for substances contaminated with chlorine compounds.

  In this second aspect, by adding a group of microorganisms containing anaerobic microorganisms and aerobic microorganisms together with the sustained-release base material, it becomes possible to increase the number of first germs and shorten the time until purification is completed. . Here, as the microorganism group, as described later, a composite microorganism agent produced by alternately repeating anaerobic conditions and aerobic conditions can be used.

  A third aspect of the present invention is the organochlorine compound according to the first aspect or the second aspect, wherein the sustained-release substrate is added after adding the cyclodextrins to the substance to be treated. This is a purification method for substances contaminated with In this third aspect, by adding cyclodextrin, the elution of the organic chlorine compound adsorbed on the substance to be treated (for example, soil particles) can be accelerated, the purification efficiency can be increased, and the sustained-release base material Since the addition allows continuous elution, the amount of cyclodextrin used can be reduced as compared with the conventional method.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the sustained-release base material is biodegradable, and is contaminated with an organic chlorine compound. This is a method for purifying the collected material. In this fourth aspect, the biodegradable sustained-release substrate is decomposed by the action of microorganisms and does not remain in the material to be treated. In addition, along with the degradation of the sustained-release substrate, the fats and surfactants contained therein are released little by little, but the degradation of the sustained-release substrate occurs with the growth of microorganisms, In synchronism with the release, the resolution of organochlorine compounds increases, and efficient purification becomes possible.

  According to a fifth aspect of the present invention, in any one of the first to third aspects, the sustained-release base material is impregnated with fats and oils and / or a surfactant using a biodegradable plastic as a carrier. This is a method for purifying a substance contaminated with an organic chlorine compound. In the fifth aspect, the organochlorine compound can be desorbed by a sustained-release base material having a simple structure in which a biodegradable plastic is impregnated with fats and oils.

  According to a sixth aspect of the present invention, in any one of the first to third aspects, the sustained-release base material is coffee koji, which is a substance contaminated with an organic chlorine compound. It is a purification method. In the sixth aspect, the organic chlorine compound can be gradually desorbed by the oil contained in the coffee cake, and it becomes possible to effectively utilize the coffee cake that is waste as a sustained-release base material. .

  According to the present invention, the organic chlorine compound adsorbed on the material to be treated can be desorbed by the action of fats and oils and a surfactant and can be easily used for microorganisms, so that the purification efficiency is high.

<Purification target>
Examples of substances to be treated by the method of the present invention include soil containing organic chlorine compounds, incineration ash, sludge and the like. Organochlorine compounds to be decomposed / removed are mainly dioxins such as polychlorinated dibenzodioxins (PCDD) and polychlorinated dibenzofurans (PCDF), including, for example, coplanar PCB (Co-PCB). Organic chlorinated solvents such as PCBs, tetrachlorethylene and trichlorethylene can also be targeted. Further, as organic chlorine-based pesticides, for example, DDT, DDE, DDD, BHC, aldrin, endrin, dieldrin, endosulfan, heptachlor, polyhaloalkyl agent, PCNB agent, DD agent, DCIP agent, chlorothalonil, dicohol, fusalide, tetradiphone, etc. It can also be applied to disassembly and removal.

<Sustained release substrate>
The sustained-release substrate used in the purification method of the present invention contains fats and oils and / or a surfactant. Here, “containing” means not only an aspect originally contained in the substance itself as a sustained-release substrate, but also an aspect in which an arbitrary carrier is supported by means such as impregnation with fats and oils or a surfactant. Used in.

  The sustained-release substrate is preferably biodegradable. In the case where the sustained-release base material has biodegradability, the fats and oils and surfactants contained therein are gradually released with the decomposition, so that the sustained-release performance can be easily obtained. Further, since the sustained-release base material has biodegradability, it does not decompose and remain in the material to be treated such as soil.

  Preferable examples of the sustained-release base material having biodegradability include a biodegradable plastic used as a carrier and impregnated with fats and oils and / or a surfactant. Here, as the biodegradable plastic, for example, any of starch, polylactic acid, aliphatic polyester, polyprolactone and the like can be used. Examples of the shape of the biodegradable plastic include a granular or powdered biodegradable plastic having an average particle diameter of 1 to 2 mm to 3 to 5 cm.

  Another preferred example of the sustained release base material is coffee candy. The coffee lees contain vegetable oils and fats and are biodegradable because they are derived from plants. By using the coffee mash, which is a waste material, as a sustained-release base material, it is possible to effectively use the coffee candy. In addition, since the said biodegradable plastics and coffee mash are comprised with the organic substance used as the carbon source of microorganisms, they function also as a continuous supply source of a carbon source.

  The amount of oil and / or surfactant contained in the sustained-release base material is preferably set to a predetermined ratio with respect to the sustained-release base material. Moreover, it is preferable that the degree of sustained release is gradually released over a certain period in a substance to be treated such as soil. In other words, if the content of fats and oils and / or surfactant is within a predetermined range and the degree of sustained release is within the predetermined range, it can be used as a sustained release base material and biodegradable If it has the property, it can be used more suitably.

In the process of treating substances to be treated, such as soil and ash, oils and fats and / or surfactants are contained in the soil and ash, etc. Make it easier to receive. As fats and oils, for example, edible oils such as vegetable oils and waste oils thereof can be used.

In addition, the surfactant acts to enhance the solubility of the organochlorine compound and promote ingestion and decomposition by microorganisms. The type of the surfactant is selected to be compatible with the condition of the substance to be treated and does not inhibit the growth of microorganisms. For example, nonionic polyoxyethylene glycol sorbitan alkyl esters, nonionic polyoxyethylene glycol p -T octylphenyl ethers and the like can be used.

<Cyclodextrin>
As a preferred form of the purification method of the present invention, it is possible to add the sustained-release substrate after adding cyclodextrins to the substance to be treated. Cyclodextrins have the effect of including organochlorine compounds and separating them from soil components. For this reason, by adding cyclodextrin prior to the addition of the sustained-release substrate, primary desorption from soil components and the like proceeds efficiently, and the decomposition performance of the organic chlorine compound is improved. Moreover, it is not necessary to add cyclodextrin regularly by using together with a sustained release base material, and the usage-amount can be reduced. Examples of cyclodextrins include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and derivatives thereof.

<Microorganism> The microorganism used for purification is not particularly limited as long as it has a resolution for an organic chlorine compound. The anaerobic microorganism or aerobic microorganism having a resolution of organochlorine compounds is not limited to a single species, and a group of microorganisms including a plurality of species and strains can also be used. Since these microorganisms can be collected by a known screening method from soil contaminated with organochlorine compounds, they can be cultured and used as seeds. Needless to say, known microbial species, strains, fungal groups and the like that are known to have a decomposing activity for dioxins and the like can be used within a range compatible with the method of the present invention.

Representative examples of anaerobic microorganisms with the ability of organochlorine compounds are anaerobic archaea such as the genus Methanobacterium, Methanosarcina, and Methanolobus, and Acetobacterium. Genus, Desulfobacterium genus, Desulfomonile genus, Dehalospirillum genus, Dehalobacter genus, Dehalobacterium genus, Dehalococcoides genus, Clostridium ) In addition to anaerobic bacteria such as genus, Citrobacter genus, Escherichia genus, Enterobacter genus, Serratia genus, Proteus genus, Shewanella genus, staphylo Coccus (Staphylococcus) genus Mention may be made of facultative anaerobic bacteria.

Representative examples of aerobic microorganisms capable of decomposing organochlorine compounds include the genus Sphingomonas, Burkholderia, Ralstonia, Pseudomonas, Nocardioides. ) Genera, Rhodococcus genera, Terrabacter genera and the like.

<Composite microbial agent>
In the purification method of the present invention, fats and / or surfactants are released from the sustained-release substrate to desorb organochlorine compounds, and microorganisms are allowed to act on the desorbed organochlorine compounds for decomposition. At this time, it is preferable to add a group of microorganisms containing anaerobic microorganisms and aerobic microorganisms together with the sustained-release base material to the substance to be treated. By adding a group of microorganisms to increase the initial bacterial count, the decomposition of the organic chlorine compound can be accelerated and the purification time can be shortened.

  As the microorganism group, a mixture of the above-exemplified microorganism species can be used, and a complex microorganism agent produced by alternately repeating anaerobic conditions and aerobic conditions can be used. Anaerobic microorganisms and aerobic microorganisms are anaerobic contained in complex microbial agents by culturing and growing together with organic matter and organochlorine compounds in a cycle that switches between anaerobic and aerobic conditions (anaerobic-aerobic cycle). And aerobic microorganisms can be used in a fully acclimatized state.

Organochlorine compounds that can be added in the production of complex microbial agents can be the same as the organic chlorinated compounds that are subject to decomposition and removal in the purification stage, as well as polycyclic compounds that can substitute for chlorinated organic compounds. Aromatic compounds, polycyclic aromatic compounds containing heteroatoms, agricultural chemicals, and the like can be used. Pesticides are easily available, and can be advantageously used when the organic chlorinated compound as a pollutant cannot be specified. Pesticides that can be used for acclimatization include organochlorine pesticides such as DDT, DDE, DDD, BHC, aldrin, endrin, dieldrin, endosulfan, heptachlor, polyhaloalkyl agent, PCNB agent, DD agent, DCIP agent, chlorothalonil , Dicohol, fusalide, tetradiphone and the like, and organophosphorus pesticides can also be used. Examples thereof include EPN, methyl dimethone, methyl parathion, parathion and the like.

Moreover, it is preferable to manufacture the composite microbial agent in the presence of fats and oils and / or surfactants. Organochlorine compounds that are contained in or attached to soil or ash when oils and / or surfactants are present in the process of treating substances such as soil and ash using complex microbial agents Can be easily removed by microorganisms, but the metabolic activity of microorganisms can be reduced at the purification stage by acclimatization with oils and / or surfactants even during the production of complex microbial agents. It is possible to efficiently act on the organochlorine compound without causing it to occur.

Moreover, when adding an organic chlorine type compound and acclimatizing in the manufacture process of a composite microbial agent, it is preferable to carry out in presence of a neutralizing agent. This is because by neutralizing the hydrogen chloride produced by dechlorination of the organic chlorine compound, the pH of the composite microbial agent can be prevented from being lowered, and the adverse effects of hydrogen chloride on microorganisms can be suppressed. As the neutralizing agent, an alkaline substance such as calcium carbonate may be used directly, but waste containing a large amount of calcium carbonate such as eggshell can be used. The use of waste as a neutralizing agent will also promote its effective use.

<Outline of Process> In a preferred embodiment of the purification method of the present invention, a composite microorganism agent containing an anaerobic microorganism, an aerobic microorganism, an organic matter derived from organic waste, or the like, on a material to be treated contaminated with an organic chlorine compound. The mixture is placed under slightly aerobic conditions, or anaerobic microorganisms and aerobic microorganisms are allowed to act on organochlorine compounds while alternately repeating anaerobic conditions and aerobic conditions. An overview of the process is shown in FIG. 1 along with the procedure for preparing the complex microbial agent.

I. Preparation of complex microbial agent: First, the complex microbial agent used in the process is to place anaerobic and aerobic microorganisms in microaerobic conditions in the presence of organic matter, or anaerobic and aerobic conditions. It is obtained by acclimatizing while alternately repeating. Preparation of a complex microbial agent can be performed using a microbial agent production apparatus. The microbial agent production apparatus is composed of a single tank or a tank divided into a plurality of tanks, and continuously composts organic matter such as garbage and dock food that are periodically added and fed by a composting method. For the preparation of this complex microbial agent, soil contaminated with dioxins, bottom mud, compost, etc. or soil, bottom mud, compost etc. not contaminated with dioxins were collected and adapted to organic matter such as garbage Can be used as an inoculum.

During the composting process, the atmosphere in the microbial agent production apparatus is placed in slightly aerobic conditions, or alternately anaerobic and aerobic conditions, and both anaerobic microorganisms and aerobic microorganisms are proliferated. Make it.

The microaerobic condition can be maintained by ventilating N ₂ gas, controlling the stirring frequency, or opening the sealed device periodically (for example, once a day). For example, the microaerobic condition can be realized by blowing N ₂ gas with moderate stirring and adjusting the oxygen concentration in the microbial agent production apparatus to 0.05 to 0.1 v / v%. Even at this concentration, an oxygen concentration sufficient for the metabolic activity of aerobic microorganisms can be supplied.

In order to make it an anaerobic condition, deaeration may be performed, but an anaerobic state can be usually created by standing for a certain period of time. On the other hand, aerobic conditions can be created by operations such as stirring and aeration. Therefore, a processing environment in which the anaerobic condition and the aerobic condition are alternately repeated can be created by intermittently performing the operation for creating the aerobic condition. More specifically, for example, an environment in which anaerobic conditions and aerobic conditions are alternately repeated can be created by stirring for about 5 minutes per hour and allowing the remaining 55 minutes to stand.

Moreover, it is preferable to set the timing of an anaerobic-aerobic cycle suitably according to the addition method of organic substance. Hereinafter, two methods of adding an organic substance (Method A) and a method of adding an organic substance every one week (Method B) will be described as an organic substance adding method. The former (Method A) is suitable for producing a large amount of complex microbial agent, and the latter (Method B) is suitable for producing a small amount of complex microbial agent.

Method A: (1) An organic substance of 0.3 to 1.0 kg (wet weight after draining) is charged once a day per 10 kg of contents of the microbial agent production apparatus. (2) Immediately after the addition of organic matter, perform mechanical stirring for 5 minutes and mix well with the contents. (3) Thereafter, batch operation is performed in an anaerobic-aerobic cycle. (4) In one cycle of anaerobic-aerobic, the ratio of anaerobic time / aerobic time is set to be between 12-60. That is, if the anaerobic time is 1 hour, the aerobic time is set between 1 and 5 minutes. (5) One cycle of anaerobic time is 1 to 6 hours.

Method B: (1) An organic substance of 1.0 kg (wet weight after draining) is charged per 10 kg of the contents of the microbial agent production apparatus every week. (2) Immediately after the addition of organic matter, perform mechanical stirring for 5 minutes and mix well with the contents. (3) Thereafter, batch operation is performed in an anaerobic-aerobic cycle. (4) In one cycle of anaerobic-aerobic, the ratio of anaerobic time / aerobic time is set to be between 12-60. That is, if the anaerobic time is 3 hours, the aerobic time is set between 3 and 15 minutes. (5) One cycle of anaerobic time is 3 to 12 hours.

In both cases A and B, the aerobic condition can be achieved by mechanical stirring. At this time, air can be blown simultaneously. Moreover, it is preferable to adjust so that a predetermined moisture content may be maintained by blowing in warm air as appropriate. The water content of the mixture to be treated in the microbial agent production apparatus is preferably set to be 30 to 60% by weight, and the optimum range is 35 to 45% by weight.

Moreover, it is preferable to make it the temperature in a microorganism agent manufacturing apparatus become 10-70 degreeC during a process, and the optimal range is 25-55 degreeC. Furthermore, it is preferable to adjust the pH of the mixture to be treated in the microbial agent production apparatus to be pH 6 to 9, and the optimum range is pH 7.5 to 8.5. In addition, while adding organic substance, pH fall (about pH 6) is seen at the initial stage, but it becomes stable between pH 7 and 9 as the number of days elapses. Therefore, although it is not necessary to adjust the pH in particular, if the pH changes beyond the range of pH 6-9, the pH can be appropriately adjusted with 6N-dilute sulfuric acid, 4N-caustic soda solution, or the like. Active growth and metabolic activity can be maintained by adjusting the water, temperature, and pH, which are basic conditions for microbial growth, to the above ranges.

The above operation has the effect of culturing and proliferating a large amount of anaerobic and aerobic microorganisms, which are inoculums, in complex microbial agents. Can be increased. In addition, since the inoculum uses a complex microbial system in nature or contaminated soil, it is not driven out by indigenous bacteria in the soil.

In addition, as described above, the preparation of the composite microbial agent can be performed by adding an organic chlorine compound such as dioxins, an agrochemical, an oil and fat, and / or a surfactant. By these additions, it is possible to obtain a complex microbial agent acclimatized with an organochlorine compound, pesticide or oil.

In the process of FIG. 1, organic matter such as garbage that has been introduced into the microbial agent production apparatus is composted, and composite microorganisms (partial anaerobic bacteria, aerobic bacteria, etc.) are combined with organic matter. Included). The remaining complex microbial agent can be effectively used as compost in fields such as agriculture and horticulture.

II. Purification of substance to be treated: In the process of FIG. 1, the composite microbial agent obtained as described above is sent to an environmental repair device. Similarly to the microbial agent production apparatus, the environment repairing apparatus can be composed of a single tank or a tank divided into a plurality of tanks, or, as another form, a breathable container as described later.

In the environmental restoration apparatus, a complex microbial agent, a substance to be treated such as soil contaminated with dioxins, and a sustained-release base material are mixed. If necessary, an appropriate amount of a neutralizing agent, a decomposition base material such as a wood chip as a base material for microbial activity, a biodegradable plastic that can be a carbon source, or an organic substance such as a dock food can be added. Here, an organic substance having a property of gradually degrading like a biodegradable plastic functions as a continuous supply source of carbon, and therefore has an advantage that it is not necessary to periodically add an additional carbon source.

Further, when the material to be treated is incinerated ash, it is alkaline in nature, so it is preferable to adjust the pH to 9 or less, preferably pH 7.5 to 8.5 before addition.

During the treatment in the environmental repair device, anaerobic microorganisms and aerobic microorganisms are allowed to act on the organochlorine compound while being placed in slightly aerobic conditions or alternately repeating anaerobic conditions and aerobic conditions. At this time, it is preferable to set the water content of the mixture to be treated in the environmental restoration device to be 30 to 60% by weight, and the optimum range is 35 to 45% by weight.

In addition, the decomposition treatment of the organic chlorine compound is preferably performed in the presence of a neutralizing agent. This is because by neutralizing the hydrogen chloride generated by dechlorination, it is possible to prevent the pH in the processing apparatus from being lowered and to suppress the adverse effects of hydrogen chloride on microorganisms. As the neutralizing agent, an alkaline substance such as calcium carbonate may be used directly, but waste containing a large amount of calcium carbonate such as eggshell can be used. The use of waste as a neutralizing agent in this way also makes effective use of it.

The setting of the microaerobic condition or the anaerobic condition and the aerobic condition in the treatment with the environmental repair device can be performed in the same manner as the treatment with the microbial agent production device. That is, the microaerobic condition can be maintained by ventilating N ₂ gas, controlling the stirring frequency, or opening the sealed device periodically (for example, once a day). For example, the microaerobic condition can be realized by blowing N ₂ gas with moderate stirring and adjusting the oxygen concentration in the environmental repair device to 0.05 to 0.1 v / v%. Even at this concentration, an oxygen concentration sufficient for the metabolic activity of aerobic microorganisms can be supplied. Furthermore, it is also possible to maintain a microaerobic condition by the stationary method mentioned later.

The timing of the anaerobic-aerobic cycle in the environmental repair device is preferably set as appropriate according to the method of adding the complex microbial agent. For example, when organic waste (organic matter) is added and treated every day (see method A), or when organic waste (organic matter) is added about every other week (see method B), etc. Accordingly, an anaerobic-aerobic cycle can be set according to the contents described for the microbial agent production apparatus. Furthermore, the water content, pH, treatment temperature, etc. of the contents can be implemented in the same manner as in the treatment with the microbial agent production apparatus.

Further, during the purification treatment, for example, several kinds of decaying fungi having an ability to resolve pollutants, anaerobic microorganisms, and aerobic microorganisms can be additionally mixed in the first half or the second half of the treatment. Furthermore, an anaerobic-aerobic cycle operating condition is selected according to the nature of the microorganism. For example, if the activity of the complex microbial agent is not sufficient in the first half of the treatment, the microorganism has a resolution of organochlorine compounds. In the latter half of the treatment, if the decomposition rate decreases due to a decrease in the concentration of the organochlorine compound in the substance to be treated, additional microorganisms having the ability to decompose the organochlorine compound can be added. can do.

By continuing the above operation until the concentration of the pollutant in the material to be treated is below the environmental standard, the organic chlorine compound can be decomposed and the material to be treated can be reliably purified.
In another embodiment of the purification method of the present invention, in the process of FIG. 1, a stationary method using a breathable container (for example, a bag, a box, etc.) can be cited as an environmental repair device. Purification by this standing method is performed by filling a gas-permeable container with a substance to be treated, a complex microbial agent, a sustained-release base material, and, if necessary, a mixture containing organic substances (stirred in advance) and leaving it still. Is done by doing. Here, the water content of the contents (the mixture) can be set to 30 to 60% by weight, preferably 35 to 45% by weight, as described above. It is also possible to provide a gas introducing part and a gas discharging part in the air-permeable container and inject air or nitrogen gas or the like to circulate. In this method, in order to prevent the diffusion of moisture from the mixture, it is preferable to cover the open portion with a breathable sheet when a partially opened breathable container is used.

  In addition, the mixture packed or boxed in a breathable container is covered with a water-impermeable sheet, and high humidity air is injected between the breathable container and the sheet, thereby dissipating moisture in the mixture. It is possible to prevent and maintain the moisture content suitable for the decomposition of the organic chlorine compound for a long period of time. Since the water content of the mixture is low, a certain level of air permeability is maintained, and air that has entered from the bag surface enters the bag and partially forms an aerobic state. In this state, a microaerobic state is created inside the breathable container, and the decomposition of the organic chlorine compound proceeds by the action of the anaerobic microorganism and the aerobic microorganism.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not restrict | limited at all by this.
Comparative Example 1
The soil contaminated with dioxins, compost with enhanced decomposition function of dioxins and wood chips were mixed at a weight ratio of 1: 1: 1, and the mixture was adjusted to a moisture content of 40% and dog food 58g Further, 50 g of vegetable oil was mixed well into a stainless steel container having an internal volume of 3 liters and filled. The container is closed with a lid, and the lid has an air inlet and an outlet. The container filled with the contents was allowed to stand in a constant temperature room at 25 ° C., and air of saturated humidity was allowed to flow at 0.5 liter / min and left for 3 months. The water content at the end of 3 months was 36%.

In addition, the compost which improved the decomposition | disassembly function of dioxins was adjusted with the following method.
That is, compost adjusted by the garbage disposal method, wood chips as the base material, and incinerated ash containing dioxin are introduced in equal amounts into a garbage disposal machine, mixed, and firewood is added daily to treat for 3 months. did. At this time, the water content was adjusted to 40% by weight.

  Dioxin concentration contained in the mixture during the treatment period of dioxin-contaminated soil was analyzed based on the “Soil Survey and Measurement Manual for Dioxins” (Environment Agency, Water Quality Conservation Bureau, Soil Agricultural Chemicals Section; issued in January 2000) The results were as follows.

表１から、３ヶ月後には初期値の３３．７％のダイオキシン類が分解されたことが判る。

From Table 1, it can be seen that 33.7% of the initial value of dioxins was decomposed after 3 months.

Example 1
The soil contaminated with dioxins, compost and wood chips with enhanced dioxin decomposition function were mixed at a weight ratio of 1: 1: 1, 1200 g of a mixture adjusted to a moisture content of 40%, 10 g of dog food and A mixture of 80 g of polycaprolactone powder, which is a biodegradable plastic, and 20 g of vegetable oil was thoroughly mixed and filled in a stainless steel container having an internal volume of 3 liters. The container is closed with a lid, and the lid has an air inlet and an outlet. The container filled with the contents was allowed to stand in a constant temperature room at 25 ° C., and air of saturated humidity was allowed to flow at 0.5 liter / min and left for 3 months. The water content at the end of 3 months was 38%.

In addition, the compost which improved the decomposition | disassembly function of dioxins was adjusted with the method similar to the comparative example 1.
As a result of analyzing the dioxin concentration contained in the mixture during the treatment period of dioxin-contaminated soil based on the “Soil Survey and Measurement Manual for Dioxins” (supra), it was as follows.

表２から、３ヶ月後には初期値の５３．５％のダイオキシン類が分解されたことが判る。

Table 2 shows that 53.5% of the initial value of dioxins was decomposed after 3 months.

Example 2
The soil contaminated with dioxins, compost and wood chips with enhanced dioxin decomposition function were mixed at a weight ratio of 1: 1: 1, 1200 g of a mixture adjusted to a moisture content of 40%, 10 g of dog food and A mixture of 80 g of polycaprolactone powder, which is a biodegradable plastic, and 20 g of vegetable oil was thoroughly stirred and filled into a bag formed of a polyester woven fabric. Put this bag in a stainless steel container with an internal volume of 5 liters having an air inlet and outlet on the lid, leave it in a constant temperature room at 25 ° C., and let air of saturated humidity flow at 0.5 liter / min. Left for 3 months. The water content at the end of 3 months was 37%.

The compost which improved the decomposition function of dioxins was prepared in the same manner as in Comparative Example 1.
As a result of analyzing the dioxin concentration contained in the mixture during the treatment period of dioxin-contaminated soil based on the “Soil Survey and Measurement Manual for Dioxins” (supra), it was as follows.

表３から、３ヶ月後には初期値の５１．６％のダイオキシン類が分解されたことが判る。

Table 3 shows that 51.6% of the initial value of dioxins was decomposed after 3 months.

  The present invention has been described above with reference to various embodiments. However, the present invention is not limited to the above embodiments, and can be applied to other embodiments within the scope of the invention described in the claims. It is.

  INDUSTRIAL APPLICABILITY The present invention can be used for purification of soil or ash contaminated with organochlorine compounds such as dioxins.

Drawing which shows the outline of a soil purification process.

Claims (6)

Add and mix a sustained-release base material containing fats and oils and / or surfactant to the material to be treated contaminated with organochlorine compounds,
Release fats and / or surfactants from the sustained release substrate to desorb or elute organochlorine compounds in the treated material,
A method for purifying a substance contaminated with an organic chlorine compound, which comprises decomposing or desorbing an organic chlorine compound by the action of a microorganism.   The method for purifying a substance contaminated with an organochlorine compound according to claim 1, wherein a microorganism group containing anaerobic microorganisms and aerobic microorganisms is added to the substance to be treated together with the sustained-release substrate. .   3. The method for purifying a substance contaminated with an organic chlorine compound according to claim 1, wherein cyclodextrins are added to the substance to be treated, and then the sustained-release substrate is added.   4. The method for purifying a substance contaminated with an organic chlorine compound according to claim 1, wherein the sustained-release substrate has biodegradability.   The organic material according to any one of claims 1 to 3, wherein the sustained-release base material is obtained by impregnating oil and fat and / or a surfactant with a biodegradable plastic as a carrier. A purification method for substances contaminated with chlorine compounds.   4. The method for purifying a substance contaminated with an organic chlorine compound according to any one of claims 1 to 3, wherein the sustained-release base material is coffee koji.

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