JP4079976B2 - Purification agent and organic chlorine compound purification method using the purification agent - Google Patents

Description

  The present invention relates to a purification agent for purifying organochlorine compounds in soil and groundwater, and a method for purifying organochlorine compounds in soil and groundwater, and more specifically, purifies soil and groundwater in which there is poor permeability or high concentration contamination. The present invention relates to a purifying agent and a method for purifying an organochlorine compound using the purifying agent.

Environmental pollution Organochlorine compounds represented by tetrachloroethylene, trichlorethylene, etc. are substances in which chlorine is added to hydrocarbons or carbon, which are artificially manufactured and used in the past as degreasing and cleaning in many industrial fields as solvents. As a result, it is recognized as a hazardous substance worldwide, because of its harmfulness to living organisms, environmental degradation, and accumulation. In Japan, environmental standards for soil and groundwater are set for 10 substances such as tetrachlorethylene and trichlorethylene. These are caused by contamination of underground soil and groundwater due to improper use and storage methods, and early purification is required.

Bioremediation of organochlorine compounds As a means of purifying an environment contaminated by harmful chemical substances, a method of purifying using microorganisms (bioremediation) has attracted attention. This method has great advantages in that power and equipment are low in cost and easy in-situ purification as compared with conventional physical and chemical treatment methods. Bioremediation is purified by adding foreign microorganisms that have high ability to decompose pollutants and purifying them by supplying nutrients to microorganisms to increase their ability to grow or metabolize pollutants. It is roughly divided into biostimulation. At present, bioaugmentation using foreign microorganisms is being put into practical use in consideration of microbial mutations, diffusion outside the region, and the like. Biostimulation, on the other hand, can be used in in-situ purification work at many contaminated sites because it can utilize native microorganisms and only add nutrients and other materials to the target environment. It has become like this.

Among organic chlorine compounds, it is known that tetrachlorethylene (PCE), trichlorethylene (TCE) and the like having a large number of chlorine are sequentially decomposed by reductive dechlorination by anaerobic microorganisms. In conventional bioremediation of organochlorine compounds, a method using this anaerobic microorganism is the mainstream.

Patent Document 1 discloses the use of hydrogen gas for microbial degradation of chlorinated aliphatic carbohydrates. The solubility of hydrogen gas in water is less than 2 mg / l, which is very low compared to the hydrogen concentration required for microbial degradation of chlorinated aliphatic carbohydrates, and this method can be used until the pollutants are completely removed. Must be continuously injected, and is not a preferable means for anaerobic bioremediation in situ.

Patent Document 2 discloses a method for promoting in-situ microbial remediation of an aquifer by injecting harmless oil. Since oil is inherently high in viscosity and low in density, a special injection technique for applying sufficient pressure is required when injecting oil from a hole into a contaminated aquifer. Also, the injected oil and aquifer water do not mix well and diffuse.

Patent Document 3 discloses a method of using an oil that permeates inert particles or a solidified oil for microbial remediation, and a material configuration thereof. In this method, the oil becomes a sustained-release carbon source, but there is a problem that the soil gap is blocked by an external substance used to make solidified oil such as a polymer or clay particles. This method is therefore not suitable for in situ bioremediation.

Patent Document 4 discloses a polylactic acid compound that slowly releases hydroxyl acid such as lactic acid that promotes the activity and reducing action of microorganisms for anaerobic bioremediation. It is widely recognized that this material is effective as a substance for decontamination of organochlorine compounds, but it requires a relatively large amount due to the high manufacturing cost and special injection technology required due to the high viscosity of the medium. It is not economical in the in-situ purification that requires the materials.

Patent Document 5 discloses a method of using a zero-valent metal emulsion for reductive dehalogenation of DNAPLs. The disadvantage of this invention is that the added iron changes form and remains in the aquifer as an iron compound.

As described above, when biostimulation is applied to in-situ purification, the contamination is often distributed over a wide range, and in order to exert the effect of microbial decomposition accordingly, nutrient sources are included in the purification target range. It is necessary to diffuse other materials. In addition, it is undesirable for the added material to remain after the contamination is purified because it causes secondary contamination.

In order to solve the problem of the conventional bioremediation agent, the present inventors disclosed a nutrient in Patent Document 6 and Patent Document 7 regarding purification of organochlorine compounds by anaerobic microorganisms. These technologies have high water-solubility and high biodegradability of materials that serve as nutrients and energy sources, so they are easy to diffuse in the soil, and an anaerobic state is created to decompose and purify the contamination. Proceed quickly. As a result, it is possible to widen the interval between the wells, and it is possible to exert an effect over a wide range by injecting from a small number of locations. Moreover, it became possible to decompose and purify the contamination before the influence of interfering substances, and it was possible to reduce the amount of work in purification and shorten the purification period. Furthermore, highly biodegradable components in the environment are selected, and after purification is completed, the material becomes carbon dioxide and water, and does not remain on site.

The problem in purifying the poorly permeable soil organochlorine compound is that the organochlorine compound is easily adsorbed to the soil. As a pollution mechanism, when organic chlorinated compounds penetrate underground, they reach the saturated layer while adsorbing to the unsaturated layer soil, and penetrate the highly permeable soil such as gravel layer and sand layer while being affected by the flow of groundwater. In many cases, it reaches the poorly permeable soil such as silt layer and clay layer to form contaminated sites.

At the same time, organochlorine compounds have a high soil / water distribution ratio (K _OC ) and are easily adsorbed to the soil. In particular, when it is contaminated at a high concentration, the adhesion to the soil is remarkable. On the other hand, microorganisms decompose organochlorine compounds dissolved in water. Therefore, even if the microorganism decomposes the organic chlorine compound in the groundwater, the organic chlorine compound is eluted again from the soil into the groundwater, so that the apparent concentration in the groundwater does not decrease and the purification period becomes longer.

In many of these pollution sites, there is contamination in poorly permeable soils, but using highly biodegradable materials will quickly purify the contamination in groundwater, but the contamination attached to the soil will be in the groundwater. Nutritional materials are consumed before elution and decomposition, and contamination remaining in the soil is re-eluted into the groundwater. Therefore, the nutritional materials are insufficient before the contamination of the soil and groundwater is purified. Therefore, it is necessary to divide and inject nutrients into a plurality of times, and space for installing the infusion device over a long period of time, infusion work burden, cost, and the like become problems. On the other hand, if a material with too low biodegradability is used, it may remain on the site after the contamination has been purified. Moreover, it may be difficult to maintain anaerobic properties in the groundwater due to the influence of groundwater flowing from upstream. At the same time, it must be considered to increase the mobility of nutrients in the soil.

In order to purify a surfactant and an oily organic chlorine compound, a method of using a surfactant to elute the organic chlorine compound from the soil and subjecting it to physical / chemical treatment is disclosed.
Patent Document 8 discloses a method of separating and recovering an organochlorine compound by desorbing it from soil with a surfactant. Patent Document 9 discloses a method of eluting pollutants from contaminated ground components with an organic pollutant elution accelerator and decomposing the pollutants with an oxidizing agent. Patent Document 10 discloses a method in which an alkali is added to an organic chlorine compound, alcohol, water and a surfactant are added as a solvent to form an emulsion, which is subjected to electrolytic reduction. In Patent Document 11, water or a surfactant aqueous solution is added to and mixed with soil containing an organic pollutant to separate the pollutant from the target soil, and then the water or surfactant aqueous solution containing the target substance is added by an analog. Methods for adsorption, separation, removal or capture are disclosed.

However, in these methods, when surfactants are added to the groundwater at the site and the organic chlorine compounds released from the soil are recovered or decomposed on the ground surface, large-scale equipment is needed for pumping and groundwater recovery, etc. It is not suitable for work sites. Further, the initial equipment cost and the operation cost are increased. In addition, these methods can be said to be technologies with high environmental loads, and are not preferable as in-situ purification methods.

Sustained release materials Some materials provide sustained release of nutrients or energy sources in a method of purifying contamination using microorganisms. For example, sustained-release electron donors such as polylactic acid are used as a purification material for organochlorine compounds. Other methods include vegetable oils, including soybean oil, canola oil and oleate, which can release electron donors over long periods of time. Vegetable oil can be an effective electron donor that activates anaerobic microorganisms and is much less viscous than polylactic acid.

However, since these materials are much more viscous than water, it is not easy to disperse the saturated layer in groundwater because the materials may block the soil gap. Therefore, diffusivity in groundwater is not so high, and it is difficult to reach the target contaminated site from the injection position, so the interval between the injection wells is narrowed, and the number of injection wells is increased, thereby reducing the purification cost and the work amount. There was a problem of increasing. In particular, the injection of large droplets of emulsified oil or pure vegetable oil impedes the free flow of groundwater in the reach area and closes the soil gap, so that the water permeability of the soil decreases at the initial injection. If so, the purification target range is narrowly limited, which is not preferable as the purification means in the original position.

In addition, the production cost of polylactic acid is very high, and a special injection technique is required to inject high concentration polylactic acid. Therefore, the total project cost is very high. Furthermore, it is necessary to quickly create an anaerobic state in order to create an active environment for microorganisms effective for biodegradation of organochlorine compounds, especially PCE and TCE, which have a large number of chlorinations. For this reason, there is a problem that the degradability is low, and therefore it takes time to create an anaerobic state, and as a result, purification is delayed and it is susceptible to interference substances.

Effective use of surfactants and oils as a means of remediating soil contamination by utilizing the fact that organochlorine compounds are liposoluble in contamination remediation using bioremediation microorganisms using surfactants and oils It is known that For example, Patent Document 12 discloses a method in which an organic chlorine compound is eluted from soil or the like with food-derived waste oils, liquid oils or liquid emulsions, and decomposed by microorganisms. Patent Document 13 discloses a method of cleaning oil-contaminated soil with a biodegradable cleaning agent, separating the cleaning solution from the soil, and purifying the cleaning solution with microorganisms. Patent Document 14 and Patent Document 15 include a method of mixing anaerobic and aerobic microorganisms with a substance to be treated contaminated with an organochlorine compound, and performing a decomposition treatment while alternately repeating anaerobic conditions and aerobic conditions. A method is disclosed in which the decomposition treatment is performed in the presence of fats and oils and / or surfactants. Patent Document 16 discloses a method of desorbing or eluting organochlorine compounds with fats and / or surfactants released from a sustained-release substrate and decomposing the desorbed organochlorine compounds by the action of microorganisms. ing.

In these methods, a means for diffusing and spreading oils and / or surfactants in situ is not considered in purifying groundwater or soil. Therefore, it can be applied to a waste treatment plant where the amount of treatment substance and the treatment range can be limited, for example, but the treatment range is not limited. It is difficult to purify, and if it is to be carried out, it is necessary to install many wells for supplying materials, and the injection work becomes complicated, so the purification cost becomes extremely high. As described above, these methods have difficulty in applicability when purifying a general polluted environment in situ.

US Pat. No. 5,602,296 US Pat. No. 5,265,674 US Pat. No. 6,331,300 US Pat. No. 6,420,594 US Pat. No. 6,664,298 JP 2005-185870 A JP 2005-288276 A Japanese Patent Application Laid-Open No. 09-075907 JP 2001-300506 A JP 2003-268583 A JP 2005-081209 A JP 2003-190922 A JP 2003-320364 A JP 2005-013218 A JP 2003-164849 A Japanese Patent Laying-Open No. 2005-262107

In the method of removing and purifying organochlorine compounds using oils or surfactants, the conventional methods mentioned above do not consider means for spreading the purification material to the contaminated site, and in most cases the plant It is limited to processing, and is difficult to apply to processing at the original position. In the case of materials that are difficult to diffuse to the contaminated site, the purification effect is limited only to the vicinity of the well where it is injected, and many injections are performed under conditions where the contamination is widespread, such as soil and groundwater contamination in the natural environment. Since wells had to be installed and infused, the purification cost was a factor. In addition, oils and surfactants for eluting organochlorine compounds usually have a large molecular structure and are not easily decomposed and may remain on the site even after purification, which may cause secondary contamination by the purification agent.

The present invention relates to a purification agent for effectively purifying an organic chlorine compound at a site where soil, groundwater and sediment, in particular, a poorly permeable soil exist, in situ and purification of the organic chlorine compound using the same. It aims to provide a method.

As a result of intensive studies to achieve the above object, the present inventors have found that any one or more of sunflower oil, safflower oil, or bran oil, stearoyl lactate, and sucrose fatty acid ester are selected from any one of the groups. It has been found that a purifier containing an oil-in-water emulsion formed from a surfactant selected from the above is optimal as a purifier for purifying organochlorine compounds in situ and effectively.

That is, the purifying agent of the present invention uses at least one of sunflower oil, safflower oil and bran oil, and a surfactant selected from one or more of the group comprising stearoyl lactate and sucrose fatty acid ester in water. It is characterized by containing an oil-in-water emulsion formed by mixing.

  An emulsion is a mixture in which other liquids that do not mix in water become fine particles and are dispersed and suspended. An oil-in-water emulsion is an oil-and-external phase in water in the outer phase (continuous phase). It is a liquid mixture in which the surface tension with the liquid is weakened, emulsified, and the outer phase liquid is dispersed as fine oil droplets in a state of wrapping oil (oil-in-water emulsion).

  The water here refers to tap water, mineral water, water treated with a water purifier (alkaline ion water, activated carbon filtered water, etc.), water used for beverages, tap water, industrial water, etc. These include ion-exchanged water, reverse osmosis water, distilled water, and ultrapure water that have been purified. In addition, the so-called fresh water such as river water, lake water, ground water, rainwater, industrial water, industrial wastewater, etc. in the natural environment has been removed from the oil, suspended matter, metals, ions, etc. contained prior to use. It is necessary to meet the standards for tap water quality. Seawater needs to be desalinated, for example, by desalination, because salt content adversely affects the structural stability of the emulsion. When the material of the present invention is used for the natural environment such as groundwater, it should be used satisfying environmental standards such as groundwater environmental standards and underground infiltration standards. It is necessary to pay particular attention to.

  To adjust the mixing ratio of at least one of sunflower oil, safflower oil and bran oil in water to an emulsion of 20 to 60% (wt%: the same applies hereinafter) in order to pass through the soil gap This is because it is necessary to consider maintaining the required emulsion size and increasing the ratio of oil that contributes to purification, which is preferable as a purification agent.

Further, the surfactant can be stearoyl lactate and / or sucrose fatty acid ester, and the surfactant has a mixing ratio in the range of 0.5% to 2.5%. This is because it is necessary to improve the stability of the oil-in-water emulsion necessary for passing through the soil gap.
When the mixing ratio is less than 0.5%, the stability of the oil-in-water emulsion cannot be improved, which is not preferable.
On the other hand, if the mixing ratio exceeds 2.5%, the surfactant exceeds the limit of miscibility with water and does not contribute to the formation of an emulsion, which is not preferable.

  In addition, the organic chlorine compound purification method of the present invention is characterized in that a nutrient material is added together with the purification agent of the present invention.

  This nutrient material has a general property of supplying a nutrient source or the like to an indigenous microorganism to become a nutrient source or an energy source that enhances the growth ability or the metabolic power of pollutants. As this nutrient material, any one or more of yeast extract, soy milk, corn milk or peptone is selected.

  These nutritional materials are particularly water-soluble, have good biodegradability, are easy to diffuse in the soil, and the process of creating an anaerobic state and decomposing and purifying the contamination proceeds rapidly. Selected as a contributing nutrient material. Further, these nutrient materials are selected as highly biodegradable components in the environment, and become carbon dioxide and water after purification is completed, and are selected as nutrient materials that do not remain in the field.

According to the purifying agent of the present invention, since the oil-in-water emulsion is composed of an oil selected as a material for purifying the contamination with an organic chlorine compound and a surfactant, the oil-in-water emulsion is Because its size is a few microns and small size and has excellent mobility in the soil, it can be diffused into the purification target area by the flow and concentration gradient of groundwater just by injecting it into the groundwater. Therefore, it is not necessary to install many injection wells in the in-situ purification, and it is possible to reduce the equipment cost and the operation cost for the injection. In addition, since it can be injected from the upstream of the groundwater to the downstream, the purification effect can be exerted in a wide range and continuously, and there is no problem even if there are buildings on the surface, and it depends on the conditions of the site. Therefore, it can be applied to many contaminated sites, and the restriction condition when applying the injection method can be eliminated.

In addition, the oil and surfactants that make up oil-in-water emulsions have a slower degradation rate than conventional low-molecular nutrient sources, and the area affected by microorganisms is maintained over a period of time. If injected into the boundary area, it will be a measure to prevent the outflow of contamination, and at the same time it will be a measure to prevent contamination from the upstream.

In addition, since the oil and surfactant, which are constituents of the oil-in-water emulsion contained in the purification agent of the present invention, can promote the elution of contamination from soil to groundwater because the contaminant is fat-soluble. The purification period can be shortened by increasing the bioavailability of contamination attached to the soil.

Furthermore, the oil and surfactant, which are constituents of the oil-in-water emulsion contained in the purifying agent of the present invention, are anaerobic microorganisms that consume oxygen and make groundwater anaerobic, and anaerobic microorganisms reduce organochlorine compounds. Hydrogen source for dechlorination. These components are selected from materials with high biodegradability among oils and surfactants, and are gradually decomposed over a period of time to produce organic acids continuously. In order to demonstrate the effect over a long period of time, it is effective against pollution that is continuously eluted from the poorly permeable soil to the groundwater and does not remain in the environment after purification. Therefore, the load on the environment is small, and it is possible to quickly restore the environment before use.

Furthermore, in the method for purifying organochlorine compounds of the present invention, nutrient sources such as yeast extract, soy milk, corn milk, and peptone are added together with the purifier containing the oil-in-water emulsion of the present invention. Types of aerobic microorganisms are used to create anaerobic conditions by consuming oxygen in the groundwater as electron acceptors, to activate and propagate aerobic microorganisms, and to decompose organochlorine compounds by microorganisms An optimal anaerobic state can be quickly created. At the same time, it acts as an electron donor when anaerobic microorganisms dechlorinate organochlorine compounds as electron acceptors. By making it possible to create anaerobic conditions in a short period that was difficult with conventional purification agents, it is possible to further shorten the purification period using anaerobic microorganisms. Due to the above advantages, it becomes possible to cope with a site having poorly permeable soil or high-concentration contamination, and the applicability and purification efficiency to sites with different conditions such as contamination distribution, soil quality, presence / absence of buildings, etc. are enhanced.

Next, the best mode for carrying out the present invention will be described.
FIG. 1 shows a contamination purification flow by the purification agent of the present invention.
The target of purification by the organic chlorine compound purification method of the present invention carried out in the pollution purification flow shown in FIG. 1 corresponds to soil, groundwater, sediment, etc. contaminated by the organic chlorine compound, and further excavated. Soil, pumped ground water, sludge, surface water, etc. are also subject to purification, but are not limited to these.

As shown in FIG. 1, the contamination purification process using the purification agent of the present invention comprises a two-stage process of a purification agent production step 1 and a contamination purification step 10.
In the purification agent production step 1, oil is added to water, and a surfactant is further added, followed by mixing (20 ° C. to 60 ° C.) using a homogenizer, a high shear mixer, and a homomixer.

As the oil that is added to water in the purification agent production process 1 and is used as a component of the purification agent, one or more of sunflower oil, safflower oil, and bran oil are selected. These oils are oils extracted from a plant body, decomposed into microorganisms to generate fatty acids, and become electron donors in a reaction in which microorganisms dechlorinate organochlorine compounds. At the same time, it has the effect of eluting organochlorine compounds adhering to the soil into groundwater. Since these materials are plant-derived substances, their harmfulness in the environment is extremely low. Therefore, these materials are preferable as purification materials for addition to the natural environment such as groundwater.

As a surfactant that is added to water in the purification agent production process 1 and is used as a component of the purification agent, among surfactants used in the field of food, medicine, and chemistry, biodegradability is high. Stearoyl lactate and / or sucrose fatty acid esters are preferably used on the condition that they are biodegraded to generate fatty acids and have good miscibility with oil. These have a good hydrophilic / lipophilic balance and high structural stability in water, and act as a surfactant for making the oil into a fine-size emulsion in water. Further, like the oil, these also have an effect of eluting organic chlorine compounds adhering to the soil into the groundwater.

In addition, these materials are plant-derived substances, have a low burden on the natural environment, and are not harmful in the environment. Therefore, these materials are used as emulsifiers in the food industry. In addition, it is not toxic to microorganisms, and when decomposed by microorganisms, it generates fatty acids that become electron donors, contributing to the detoxification of organochlorine compounds as electron acceptors by microorganisms. Therefore, these materials are preferable as purification materials for addition to the natural environment such as groundwater.

In general, surfactants include stearoyl lactates such as sodium stearoyl lactate, sucrose fatty acid esters such as DKF-160 and DKF-100, polysorbates such as Tween 60, sorbitan esters such as Span 60, and soy lecithin. However, polysorbate series, sorbitan ester series, soybean lecithin and the like are not suitable as purification materials in groundwater environments because the structural stability of the emulsion is not sufficient in water and phase separation easily occurs.

In this purification agent production process 1, an oil-in-water emulsion is produced using a high-cost equipment homogenizer, a high shear mixer, or a low-cost equipment homomixer that determines the oil droplet size of the oil-in-water emulsion. Can do.
In this case, by adding oil to water and further adding a surfactant, the temperature range when mixing with a homogenizer, a high shear mixer, and a homomixer is set to 20 to 60 ° C, more preferably 40 to 60 ° C. It is possible to form an oil-in-water emulsion that is fine and stable in water.
In this case, if the temperature is less than 20 ° C., it is difficult to produce a fine uniform emulsion, and if it is less than 40, it is not easy to produce a fine uniform emulsion. On the other hand, when it exceeds 60 ° C., it becomes difficult to form a stable emulsion.

The contamination purification step 10 is performed by the purification agent of the present invention obtained in the above-described purification agent production step 1.
As a substance to be purified by carrying out the pollution purification process 10, an organic chlorine compound is applicable, and in aliphatic, tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, 1,1-dichloroethylene, chloride Examples of aromatics include vinyl monomers, trichloroethane, dichloroethane, chloroethane, carbon tetrachloride, chloroform, dichloromethane, chloromethane, dioxins such as polychlorinated dibenzodioxin and polychlorinated dibenzofuran, PCBs such as coplanar PCB, etc. It is not limited to.

In this contamination purification process 10, after preliminary work such as site survey, purification design, injection well, observation well installation, etc., dilution / concentration adjustment of the purification agent is performed based on the purification design. Thereafter, the emulsion liquid is injected, and a nutrient source (such as yeast extract) is injected. The injected cleaning agent diffuses in the soil and groundwater by the injection pressure and the fluidity of the oil-in-water emulsion itself. That is, the purification agent of the present invention is highly miscible and dispersible in water, and when added to groundwater, it moves in the soil gap by the flow of groundwater or by the pressure of injection, and easily diffuses into the purification target range. .

The diffused oil-in-water emulsion produces an organic acid by biodegradation by an indigenous microorganism and elutes an organic chlorine compound adhering to the soil into water so that it can be dechlorinated by the microorganism. Organochlorine compounds are generally poorly water soluble and more readily adsorbed to the soil in the presence of organic matter in the soil, and are distributed to the soil rather than groundwater at many contaminated sites. Therefore, even if the organic chlorine compound in the groundwater is removed or decomposed, the organic chlorine compound is re-eluted from the soil according to the solubility, so that it may be necessary to continue the purification work indefinitely. On the other hand, the purifying agent of the present invention can elute organochlorine compounds adhering to the soil into the groundwater due to the surface active effect and the cosolvent effect.

Organochlorine compounds eluted in groundwater are detoxified by reductive dechlorination as electron acceptors by microorganisms, so even with high-concentration pollution, which has been prone to long-term purification with conventional purification materials. It becomes possible to promote the purification effect.

Furthermore, when the oil-in-water emulsion in the groundwater is gradually degraded by indigenous microorganisms, fatty acids such as hydrogen, acetic acid, propionic acid, and lactic acid are generated, and the anaerobic microorganisms desorb organochlorine compounds as electron acceptors. Acts as an electron donor for chlorination.
In the contamination purification process 10 described above, reductive dechlorination / purification of an organic chlorine compound is performed.

In the contamination purification step 10, it is preferable to add a nutrient material containing any one or more of yeast extract, soy milk, corn milk and peptone together with the purification agent of the present invention. These all act as nutrient sources that promote the growth and activation of microorganisms.

Soy milk and corn milk are liquids produced from soybeans and corn, respectively. Soymilk is a white liquid squeezed from soybeans in the tofu production process and is composed of many types of amino acids including water-soluble protein and glycinin, and is rich in amino acids and proteins. It acts as a suitable nutrient source for various microorganisms regardless of anaerobic. Proteins contained in soy milk and corn milk are water-soluble, are easily diffused in groundwater, and can be supplied in a wide range after being added to groundwater. Furthermore, since it contains water-soluble vitamins, it is preferable as a material for activating microorganisms.

A yeast extract is an extract extracted by treating a useful component of yeast with autolysis, enzymes, hot water or the like. Since it contains amino acids, nucleic acid-related substances, minerals, and vitamins as main components, it is preferable as a nutrient source for microorganisms. In addition, according to the current classification of foods and food additives, yeast extract is not a food additive, but is classified as a food in the same manner as soy sauce and kelp extract, so it is highly safe for the environment. In addition, amino acids produced by the decomposition of yeast extract by microorganisms and other components also act as nutrient sources for the microorganisms, and thus are preferable as components of materials used for purification.

Peptone is a soluble substance obtained by treating natural proteins by hydrolysis or the action of certain enzymes (pepsin, papain, pancreatin, etc.). It is a substance used in bacterial growth media, various fermentations, and pure cultures. When peptone is supplied to microorganisms, it is broken down to produce amino acids. Since this amino acid is a nutrient source for many indigenous microorganisms, it is preferable as a material used for purification.

  These are sources of nutrients such as amino acids, minerals, and vitamins for many microorganisms, including aerobic to anaerobic, and they consume oxygen and become anaerobic when activated and proliferated. In addition, it is used to promote reductive dechlorination of organochlorine compounds by activating and multiplying microorganisms that decompose organochlorine compounds in an anaerobic state.

The oil-in-water emulsion obtained in the purification agent production process 1 and used in the pollution purification process 10 is an intermediate oil droplet size of 0.3 microns or less with respect to 1 micron of the soil pore in order to prevent a large decrease in soil permeability. A ratio is desirable. It is important that the average oil droplet size be 1 micron or less unless emulsified oil injection is performed in coarse soils. In particular, when installing a permeable reaction wall as a countermeasure against pollution outflow and contamination, care must be taken because the flow of groundwater is affected by the decrease in water permeability.

Furthermore, considering the stability and good mobility in water, the size of the oil-in-water emulsion is preferably 1 micron or less. In order to obtain this oil-in-water emulsion, the surfactant is dispersed in hot water before mixing, and the surfactant solution and oil are mixed in a mixer.

The oil mixing ratio in the purifier of the present invention is preferably 10-65%. Furthermore, since small droplet sizes with medium viscosity and good stability are optimal, the oil mixing ratio is preferably 20-60%, most preferably the oil mixing ratio in the oil-in-water emulsion is 45%. The condition of ~ 55% is good.
If the mixing ratio is less than 10%, an emulsion having a sufficient effect cannot be obtained, while if it exceeds 65%, an emulsion in which oil-in-water droplets are finely and uniformly dispersed cannot be obtained. On the other hand, if it is less than 20%, it is impossible to obtain a well-balanced small droplet size emulsion having medium viscosity and good stability. If it exceeds 65%, the viscosity becomes excessive and fluidity is impaired.

When injecting the oil-in-water emulsion thinned into the aquifer in the contamination purification process 10 in order to keep the groundwater or the soil in suitable growth conditions, the pH of sodium carbonate, sodium bicarbonate, etc. It is good to adjust pH to the range of 5-9 by adding the material for adjusting to an oil-in-water emulsion.

Examples of the purification agent and the organic chlorine compound purification method of the present invention will be described below. Each of the following examples relates to a purification agent production step 1 in the contamination purification flow shown in FIG. 1 by Examples 1 to 8 and Comparative Example 1 and the purification agent of the present invention. Further, Example 7 and FIG. 2 relate to the biodegradability of the cleaning agent of the present invention. Examples 8 to 10 and FIGS. 3 to 24 relate to the contamination purification process 10 and the organic chlorine compound purification method of the present invention and comparative examples thereof.
[Example 1]
The effect of the surfactant concentration on the stability of the produced emulsion was observed by keeping the oil mixing ratio constant and changing the surfactant concentration in the water. For this purpose, 1 g, 2.5 g, and 5 g of a surfactant SSL (SODIUM STEAROYL LACTYLATE) are weighed, and each is combined with hot water and dispersed to 100 g to obtain a dispersion of the surfactant. Manufactured. Further, 100 g of sunflower oil was added thereto and mixed with a laboratory mixer for 10 minutes. The stability of the emulsion was visually observed, and the influence of the SSL mixing ratio on the stability of the oil-in-water emulsion was evaluated. Here, the criterion for evaluation was the size of the emulsion after 24 hours from the production. When the size is 10 μm or more, or when an oil film is formed and an emulsion is not formed, it is bad (×), when it is 5 μm or more and less than 10 μm is acceptable (●), and when it is 1 μm or more and less than 5 μm, it is good (◯), The case of less than 1 μm was regarded as excellent (優秀). The results are shown in Table 1.

  As shown in Table 1, when the mixing ratio of SSL in the emulsion is 0.5%, there is no particular influence on the stability of the oil-in-water emulsion, but when the SSL mixing ratio is 1.25%, the oil-in-water type It had a good effect on the stability of the emulsion, and an excellent effect on the stability of the oil-in-water emulsion at an SSL mixing ratio of 2.5%. From this result, it was found that an emulsion having good stability can be produced when the concentration of the surfactant with respect to the emulsion liquid is 2.5% by weight.

[Example 2]
As an evaluation test regarding the purifying agent of the present invention, 5 g of various surfactants such as sodium stearoyl lactate, DKF-160, DKF-110, DKF-50, Tween 60, and Span 60 were dispersed to 100 g together with water. A surfactant-water mixture was prepared and 100 g of sunflower oil was placed in a laboratory mixer and stirred for 10 minutes. The stability of the emulsion thus obtained was visually observed, and the influence of various surfactants on the stability of the oil-in-water emulsion was evaluated. Here, the criterion for evaluation was the size of the emulsion after 24 hours from the production. When the size is 10 μm or more, or when an oil film is formed and an emulsion is not formed, it is bad (×), when it is 5 μm or more and less than 10 μm is acceptable (●), and when it is 1 μm or more and less than 5 μm, it is good (◯), The case of less than 1 μm was regarded as excellent (優秀). The evaluation results are shown in Table 2.

  As shown in Table 2, when the span 60 is used, the effect on the stability of the oil-in-water emulsion is poor, but when the tween 60 or DKF-50 is used, the oil-in-water emulsion The stability of the oil-in-water emulsion when DKF-110 or DKF-160 is used, and the oil-in-water droplet when SSL is used. It can be seen that the stability of the mold emulsion was very positively affected. From these results, it is understood that among the surfactants, stearoyl lactate surfactant SSL and sucrose fatty acid ester surfactants DKF-160 and DKF-110 are surfactants that can be used effectively.

[Example 3]
As an evaluation test regarding the purifying agent of the present invention, appropriate evaluation tests of various oils were performed. First, 5 g of sodium stearoyl lactate and water were combined to make 100 g into a laboratory mixer, and further 100 g of sunflower oil was added and stirred for 10 minutes. Similar samples were prepared using safflower oil, bran oil, castor oil, tonsil oil, and sesame oil. The effect of type was evaluated. Here, the criterion for evaluation was the size of the emulsion after 24 hours from the production. When the size is 10 μm or more, or when an oil film is formed and an emulsion is not formed, it is bad (×), when it is 5 μm or more and less than 10 μm is acceptable (●), and when it is 1 μm or more and less than 5 μm, it is good (◯), The case of less than 1 μm was regarded as excellent (優秀). The evaluation results are shown in Table 3.

  As shown in Table 3, when sesame oil is used, the effect on the stability of the oil-in-water emulsion is poor, but when tonsil oil is used, the stability of the oil-in-water emulsion is good. When castor oil is used, the stability of the oil-in-water emulsion is very good. When sunflower oil, safflower oil, or bran oil is used, the oil-in-water emulsion is used. It can be seen that this has had a very good influence on the stability of

[Example 4]
As an evaluation test for the cleaning agent of the present invention, an oil-in-water emulsion was prepared by changing the mixing ratio of oil in the oil-in-water emulsion. One of the main factors that determines the stability of an emulsion is the oil content in the emulsion. Water was mixed so that it might become 100 g combining with 5 g of SSL, and the SSL liquid mixture was created. Then, the SSL mixture and sunflower oil were mixed at the ratio shown in Table 4, and the stability of the emulsion was observed. As shown in Table 4, it was found that an increase in the oil content in the emulsion resulted in the instability of the emulsion, and a stable emulsion could be made up to 60% oil content in the emulsion.

[Example 5]
In order to verify the stability of emulsions produced using multiple types of surfactants such as sodium stearoyl lactate and sucrose fatty acid ester (DKF), interfaces such as sodium stearoyl lactate (SSL) and sucrose fatty acid ester (DKF) An oil-in-water emulsion was prepared with a mixture of active agents. 100 g of sunflower oil is put into a laboratory mixer, and 100 g of a mixture of 50 g of a mixed solution prepared by mixing 2.5 g of sodium stearoyl lactate or 2.5 g of sucrose fatty acid ester with water is added for 10 minutes. Mix with blender. As a result, it was confirmed that an emulsion produced by using a surfactant composed of sodium stearoyl lactate and a sucrose fatty acid ester in combination was stable.

Delete

[Example 6]
During the preparation of the oil-in-water emulsion, the stability of the emulsion was observed using various salts. First, a surfactant-water mixture was prepared by mixing 5 g of a surfactant and water to make 100 g, and 50 g of this mixture and 50 g of oil were mixed to produce 100 g of an emulsion. Furthermore, predetermined amounts of sodium chloride, calcium chloride, sodium carbonate, sodium bicarbonate, diammonium phosphate and sodium lactate were added thereto, and the stability of the emulsion was observed. The results are shown in Table 6. It can be seen from Table 6 that phase separation is prevented by limiting the salt concentration and phase separation occurs by increasing the salt in the emulsion.

[Example 7]
The decomposability test of the cleaning agents of Examples 7-1 to 5 and Comparative Example shown in Table 7 was carried out under an aerobic environment. For this purpose, a 5 L glass bottle was used, and the emulsion was mixed with 3 L of water at a concentration of 500 mg / L, 2% of sludge was added, and the experiment was conducted in an aerobic environment while stirring with a stirrer. The degradability of the cleaning agent was measured by periodically analyzing the chemical oxygen demand (COD). The supply performance of nutrient sources for microorganisms is required to be about 100 mg / L or more as COD. FIG. 2 shows the time course and the tendency of the emulsion to degrade. As shown in FIG. 2, it can be seen that in Examples 7-1 to 5 which are the purifying agents of the present invention, COD remains for a long period of time and has high sustainability. On the other hand, in the case of the yeast extract of the comparative example, which is a widely used microbial nutrient source, the COD became 100 mg / L or less in about 30 days. From the above result, it was shown that the sustainability of nutrient supply of the purifier of the present invention is high.

[Example 8]
A microcosm experiment was conducted to evaluate the effect of the cleaner of the present invention on the degradation of volatile organochlorine compounds (VOC) by microorganisms. For this purpose, 5 L of groundwater contaminated with trichlorethylene (TCE) was used for microcosmo. The contamination concentration of groundwater was about 5 mg / L with trichlorethylene. Transfer groundwater into a 5 L glass container in an anaerobic chamber, add each of the purifiers of the present invention shown in Table 8 to Microcosmo to 500 mg / L, and further add an air bag to the mouth of the container. A sampling port was attached and microcosms were cultured in an anaerobic environment. The concentrations of trichlorethylene, cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene were measured periodically over 150 days. The measurement method conformed to JIS-K0125. The number of days required for purification of each of TCE, c-DCE, and VC is shown in Example 8-1, Example 8-2, Example 8-3, Example 8-4, Example 8-5, and Example 8-6. , Example 8-7, Example 8-8, Example 8-9, Example 8-10, Example 8-11, Example 8-12, Example 8-13, Example 8-14, Implementation It shows in Table 8 as Example 8-15, Example 8-16, and Example 8-17. 3 to 19 show changes in the elapsed time (days) and the VOC concentration (mg / L) in the course of the tests of Examples 8-1 to 17.

    As shown in Table 8 and FIGS. 3 to 19, it was shown that volatile organochlorine compounds in groundwater can be purified by the purification agent of the present invention.

[Example 9]
A microcosm experiment was conducted to evaluate the effect of the cleaner of the present invention on the decomposition of volatile organochlorine compounds by microorganisms, particularly when the contamination was high. For this purpose, 5 L of groundwater contaminated with trichlorethylene was used for microcosm. The contamination concentration of groundwater was about 5 mg / L with trichlorethylene. Trichlorethylene was added to the groundwater so that the concentration of trichlorethylene was 20 mg / L, the groundwater was transferred to a 5 L glass container in an anaerobic chamber, and sunflower oil, SSL, yeast extract (Example) and yeast were used as the purifier of the present invention. Only the extract (comparative example) was added to the microcosm to 500 mg / L, and an air bag and a sampling port were attached to the mouth of the container, and the microcosm was cultured in an anaerobic environment. The concentrations of trichlorethylene, cis-1,2-dichloroethylene, vinyl chloride and ethylene were measured periodically. The measurement method conformed to JIS-K0125. The results are shown in FIG. 20 (Example) and FIG. 21 (Comparative example). Here, T-VOC represents the total amount of trichlorethylene, cis-1,2-dichloroethylene, and vinyl chloride. Moreover, in FIG. 22, the case of the Example and the comparative example was shown about T-VOC. As shown in FIG. 20 to FIG. 22, in the case of the purifying agent of the present invention, the effect is continuously exhibited even in the case of a high concentration, leading to purification. It can be seen that although the purification rate is faster than that of the purification agent of the present invention, the effect gradually diminishes and the final purification is not achieved. From the above, it was proved that the purifying agent of the present invention continuously exerts the purifying effect against high concentration of contamination.

[Example 10]
A microcosm experiment was conducted to evaluate the effect of the cleaner of the present invention on the degradation of volatile organochlorine compounds by microorganisms, particularly the effect on soil contamination. For this purpose, 2.5 microliters of soil contaminated with trichlorethylene and 2.5 L of groundwater were added to a 5 L glass container in an anaerobic chamber to prepare six microcosms. Furthermore, the purifier (Example) of the present invention consisting of sunflower oil, SSL and yeast extract and only the yeast extract (Comparative Example) were added to three microcosms to give 500 mg / L, respectively, and filled up further. After adding groundwater until it was, an air bag and a sampling port were attached to the mouth of the container, and microcosms were cultured in an anaerobic environment. The concentrations of trichlorethylene, cis-1,2-dichloroethylene, vinyl chloride and ethylene were measured periodically. The measurement method conformed to JIS-K0125. The average result of three microcosms is shown in FIG. 23 (Example) and FIG. 24 (Comparative example). Here, T-VOC represents the total amount of trichlorethylene, cis-1,2-dichloroethylene, and vinyl chloride. As shown in FIG. 23 and FIG. 24, in the case of the purifying agent of the present invention, VOCs are leached from the soil by the elution effect at the initial stage, and further, the effect is continuously achieved and purification is achieved. On the other hand, in the case of the comparative example, it can be seen that the contamination has not been eluted from the soil, or the purification has not been finally achieved. From the above, it was proved that the purification agent of the present invention exerts a purification effect continuously against soil contamination.

The contamination purification flow by a purification agent is shown. It is a figure which shows the result of having implemented the decomposability | decomposability test of the purifier of Examples 7-1 to 5 and a comparative example under aerobic environment. In Example 8-1 which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE and VC was performed. It is a figure which shows the number of days required for. In Example 8-2, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-3, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-4, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-5, which is a microcosm experiment conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-6, which is a microcosm experiment conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organic chlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-7, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-8, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-9, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-10, which is a microcosm experiment conducted to evaluate the effect of the cleaner of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-11, which is a microcosm experiment conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Examples 8-12, which are microcosm experiments conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organochlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-13, which is a microcosm experiment conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Examples 8-14, which are microcosm experiments conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Examples 8-15, which are microcosm experiments conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Examples 8-16, which are microcosm experiments conducted to evaluate the effect of the cleaning agent of the present invention on the decomposition of volatile organochlorine compounds (VOCs) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. In Example 8-17, which is a microcosm experiment conducted to evaluate the effect of the purification agent of the present invention on the decomposition of volatile organic chlorine compounds (VOC) by microorganisms, purification of TCE, c-DCE, and VC was performed. It is a figure which shows the number of days required for. As an example of the purifying agent of the present invention, sunflower oil, SSL and yeast extract were added to microcosm to 500 mg / L, and the microcosm was cultured in an anaerobic environment to obtain trichlorethylene, cis-1,2-dichloroethylene. It is a figure which shows the result of having measured the density | concentration of vinyl chloride and ethylene regularly. As a comparative example of the present invention, only yeast extract is added to 500 mg / L microcosm, and microcosm is cultured in an anaerobic environment, and the concentrations of trichlorethylene, cis-1,2-dichloroethylene, vinyl chloride, and ethylene are periodically increased. It is a figure which shows the measurement result. It is a figure which shows the change of T-VOC in the Example shown in FIG. 20, and the comparative example shown in FIG. It is a figure which shows the result of having performed the microcosm experiment and evaluating the density | concentration of a volatile organochlorine compound regularly in order to evaluate about the effect with respect to the soil contamination of the cleaning agent of the Example of this invention. It is a figure which shows the result of having periodically measured the density | concentration of the volatile organochlorine compound by performing a microcosm experiment using only a 500 mg / L yeast extract as a comparative example with respect to the Example of this invention.

Claims (2)

Formed by mixing in water with one or more of sunflower oil, safflower oil, bran oil and a surfactant selected from one or more of the group comprising stearoyl lactate, sucrose fatty acid ester A soil or ground water or sediment purifier comprising an oil-in-water emulsion. A method for purifying organochlorine compounds, comprising adding a nutrient material together with the oil-in-water emulsion according to claim 1 to a contaminated medium, wherein the nutrient material is yeast extract, soy milk, corn milk or peptone The purification | cleaning method of the organic chlorine compound containing any one or more of these.

Images