JP2010158653A - Decontaminating agent for soil and ground water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decontaminating agent for soil and ground water, of which particle size of an oil drop is small enough and which is excellent in diffusibility in soil and can be uniformly distributed in soil and ground water to achieve sufficient decontamination of a contaminant. <P>SOLUTION: The decontaminating agent for soil and ground water decomposes the contaminant by activating microorganisms existing in either or both of contaminated soil and contaminated ground water. The decontaminating agent comprises oil-in-water type emulsion obtained by emulsifying liquid oil and fat, water and a surfactant of 0.3 to 10 wt.% of weight of the liquid oil and fat. A mean particle size of the oil drops is 1 to 3 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a soil, groundwater for activating microorganisms present in either or both of soil and groundwater contaminated with a pollutant such as halogenated hydrocarbons and oil to decompose the pollutant It is related with the purification agent for urine.

In recent years, pollutants that cause environmental destruction or have an adverse effect on living organisms have been detected in soil and groundwater, and environmental pollution due to these pollutants has become a problem. Various methods have been used to purify contaminated soil and groundwater. Conventionally, physical methods such as excavating, sucking, or pumping contaminated soil and groundwater, washing them with water or solvent externally, or detoxifying them, etc. Many chemical methods were used. However, such a physicochemical method is high in cost and low in operability, so that it has been limited to application in purification of a high-concentration and narrow contaminated zone. In addition, when there is an operating facility such as a plant on contaminated soil or groundwater, there are many cases where a method such as excavating the soil is impossible.
When soil and groundwater contaminated areas cover a wide area, in-situ treatment is desired. In recent years, it is possible to easily and inexpensively purify soil contaminated with pollutants. Biological purification methods have been proposed and put into practical use.

  The biological purification method is a purification technique for repairing contaminated soil using the ability of microorganisms to decompose chemical substances. This is a method of attenuating pollutants by using microorganisms originally present in contaminated soil and groundwater, which eliminates the need for excavating contaminated soil and extracting pollutants and reduces the cost of soil in situ. Therefore, it is attracting attention as an effective technology for the purification of contaminated soil. As such a technology, a technology is known in which nutrients are supplied to soil and groundwater to activate microorganisms originally present in the soil and promote the decay of pollutants. By adding effective nutrients to soil and groundwater, the decomposition activity of microorganisms indwelling in contaminated soil and groundwater can be increased to purify contaminated soil and groundwater, and to efficiently decompose and remove pollutants. Is known.

  As nutrients effective for the growth and survival of the microorganism, for example, Patent Document 1 discloses liquid fats and oils, 0.5 to 50% by weight of the weight of liquid fats and oils, and the weight of nonionic surfactants. Disclosed is a soil and groundwater purifier comprising an emulsion obtained by emulsifying 50 to 400% by weight of a polyhydric alcohol and water in an oil-in-water type, and having an average particle size of oil droplets of 50 μm or less.

JP 2007-83169 A

  However, the soil and groundwater purifier disclosed in Patent Document 1 has a large average particle diameter of oil droplets of 50 μm or less, and is sufficient in terms of diffusibility in the soil when added to the soil. Therefore, there is a local area where the purifier is not reachable, and there is a possibility that the pollutant cannot be sufficiently purified.

  Therefore, in view of the problems of the prior art, the present invention has a sufficiently small oil droplet size, excellent diffusibility in the soil, and can be uniformly distributed in the soil and groundwater. The object is to provide a soil and groundwater purification agent that can be sufficiently purified.

In order to solve the above problems, in the present invention, soil that activates microorganisms present in either or both of contaminated soil and groundwater and decomposes the pollutant, a groundwater purifier, liquid oil and fat, It is made of an emulsion obtained by emulsifying a surfactant of 0.3 to 10% by weight of liquid oil and fat and water in an oil-in-water type, and has an average particle diameter of oil droplets of 1 to 3 μm.
Thereby, the particle size of the oil droplets is sufficiently small, excellent in diffusibility in the soil, and can be uniformly distributed in the soil / ground water, so that the contaminants can be sufficiently purified.

Moreover, in the soil which activates the microorganisms which exist in any one or both in contaminated soil or groundwater, and decomposes | disassembles a pollutant, ground oil purifier, liquid fat and oil, and 0.3 to 10 of this liquid fat weight It consists of an emulsion obtained by emulsifying a weight percent surfactant, a polysaccharide of 20 to 300 weight percent of the surfactant weight, and water into an oil-in-water type, and has an average particle diameter of oil droplets of 1 to 3 μm. It is characterized by that.
Thereby, the particle size of the oil droplets is sufficiently small, excellent in diffusibility in the soil, and can be uniformly distributed in the soil / ground water, so that the contaminants can be sufficiently purified.
Furthermore, the stability of the emulsion can be increased by using polysaccharides.

The surfactant is a nonionic surfactant.
Thereby, an emulsion can be obtained stably.

The surfactant is a mixture of a nonionic surfactant and an anionic surfactant in an amount of 20 to 300% by weight based on the weight of the nonionic surfactant.
Anionic surfactants are less toxic to aquatic organisms than nonionic surfactants. Therefore, mixing anionic surfactants and using them as surfactants increases the safety for aqueous organisms.

Moreover, the said liquid fats and oils are mix | blended 20 to 80weight% in the said emulsion.
As a result, a stable oil-in-water emulsion having fluidity can be obtained.

  As described above, according to the present invention, the particle size of the oil droplets is sufficiently small, excellent in diffusibility in the soil, and can be uniformly distributed in the soil and groundwater, so that the contaminants are sufficiently purified. It can provide a soil and groundwater purification agent.

It is a block diagram of an emulsification apparatus. It is the table | surface which put together the result of the emulsification stability by the difference in oil droplet diameter, the utilization degree of microorganisms, a residual degree, and construction appropriateness. It is the table | surface which put together the result of having observed the oil particle. It is the table | surface which put together the measurement result of the density | concentration of PCE, TCE, cis-DCE, ORP, and TOC.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

Examples of the liquid oil used in the purification agent of the present invention include soybean oil, rapeseed oil, safflower oil, sesame oil, bran oil, corn oil, cottonseed oil, peanut oil, castor oil, camellia oil, sunflower oil, jojoba oil, palm oil and the like. Is mentioned.
It is preferable that the compounding quantity of the liquid fat in an emulsion is 20 to 80 weight%. If the blended amount of the liquid fats and oils in the emulsion is less than 20% by weight, the stability of the emulsion is lowered and it may become non-uniform during storage, which is not preferable. Further, if the blending amount of the liquid fat in the emulsion is more than 80% by weight, it becomes difficult to obtain an oil-in-water emulsion, and even if an oil-in-water emulsion is obtained, it has almost no fluidity. In addition to being difficult to handle, injection into contaminated soil and groundwater becomes difficult. Therefore, in order to obtain an emulsion having high stability and fluidity that can be easily injected into contaminated soil, the amount of liquid oil in the emulsion should be 20 to 80% by weight as described above. preferable.
Furthermore, if the blending amount of the liquid fat is small, the amount of the cleaning agent injected into the soil / groundwater increases, so that the blending amount should be 30% by weight or more in consideration of transportation and storage costs and construction time. preferable. On the other hand, if the amount of liquid oil and fat is large, the emulsion clay obtained becomes high, making it difficult to inject into soil and groundwater, and in some cases, a special device is required. In order to inject into soil / ground water, the blending amount is more preferably 70% by weight or less. That is, it is more preferable that the blending amount of the liquid fat in the emulsion is 30 to 70% by weight.

Further, the surfactant is blended in an amount of 0.3 to 10% by weight of the amount of liquid fat, and more preferably 1 to 7% by weight of the weight of liquid fat.
When the blending amount of the surfactant is less than 0.3% by weight of the liquid fat / oil, it is possible to emulsify to an oil droplet average particle diameter of 3 μm or less, but it becomes difficult to maintain the emulsified state stably for a long period of time. . In addition, if it exceeds 10% by weight of the liquid fat, a stable emulsion having an oil droplet average particle diameter of 3 μm or less can be obtained, but the amount of the surfactant used for producing the purifier is increased, resulting in an increase in cost. Therefore, it is not preferable.

The surfactant is a nonionic surfactant or a mixture of a nonionic surfactant and an anionic surfactant in an amount of 20 to 300% by weight based on the weight of the nonionic surfactant.
Nonionic surfactants include alkyl polyoxyethylene ether, fatty acid methyl ester ethoxylate, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene glycerin fatty acid ester. , Cocamide diethanolamine, saponin and the like.
Anionic surfactants include fatty acid sodium, fatty acid potassium, alkyl sulfate, alkyl ether sulfate (sodium higher alcohol ethoxy sulfate), sodium caseinate, lactic acid fatty acid ester (such as sodium stearoyl lactate), glutamic acid fatty acid ester (such as sodium stearoyl glutamate) ), Cocoylglycine potassium, lysolecithin and the like.

The polysaccharide is blended in an amount of 20 to 300% by weight of the surfactant, and more preferably 30 to 150% by weight. Since the polysaccharide has the property of imparting viscosity to the liquid, the stability of the emulsifier can be increased by using the polysaccharide.
When the ratio of the polysaccharide is less than 20% by weight of the surfactant, an advantageous effect in emulsion stability cannot be obtained as compared with the case where the polysaccharide is not used. On the other hand, when the ratio of the polysaccharide exceeds 300% by weight of the surfactant, it is difficult to obtain a stable oil-in-water emulsion having an oil droplet average particle diameter of 3 μm or less.

  Examples of the polysaccharide include dextrin, reduced starch syrup, oligosaccharide, carboxymethyl cellulose (CMC), and it is particularly preferable to use dextrin and CMC from the viewpoint of increasing the stability of the emulsifier.

As water, pure water may be used, or water in which a compound containing nitrogen and phosphorus is mixed may be used.
Examples of the compound containing nitrogen include urea and ammonium sulfate.
Examples of the compound containing phosphorus include dipotassium monohydrogen phosphate, monopotassium dihydrogen phosphate, and sodium tripolyphosphate.

  In order to purify contaminants such as volatile organic chlorine compounds contained in soil and groundwater with the purification agent of the present invention, a method of drilling a well in the ground and injecting the purification agent of the present invention into the well can be mentioned. . Since the purifying agent of the present invention has good diffusibility in soil, the purifying agent diffuses in the downstream direction of the flow of groundwater in the downstream direction of the flow of groundwater even if it is injected from one well. It penetrates into the soil and can perform a wide range of purification. The purification agent of the present invention may be diluted into several to several tens of times as needed and then injected into the ground. In addition, when the purifying agent of the present invention is injected into the ground, injecting organic nutrients such as sugars and amino acids in combination can improve the immediate effect of the pollutant purification action by the purifying agent.

(Emulsifying device)
FIG. 1 is a configuration diagram of an emulsification apparatus.
In FIG. 1, two tanks T1 and T2 are prepared, the tank T1 contains a water phase component, and the tank T2 contains an oil phase component.
The tanks T1 and T2 are respectively provided with raw material supply paths C1 and C2 for supplying the raw materials in the tank, and the raw material supply paths C1 and C2 are respectively provided with pumps P1 and P2. Further, the downstream sides of the raw material supply paths C1 and C2 merge into the combined flow path 1, and a mixing chamber 10 is provided in the middle of the combined flow path 1.

  The mixing chamber 10 is provided with a concentric housing tube portion 11 having a flow passage cross-sectional area that is twice or more the flow passage cross-sectional area of the combined flow passage 1. A collision plate 12 having an edge portion 13 that protrudes toward the upstream side at a peripheral portion larger than the inner diameter is fixed and installed concentrically with the housing tube portion 11, and the outer peripheral surface of the edge portion 13 of the collision plate 12 A flow path cross-sectional area constituted by a gap between the inner peripheral surface of the housing cylinder part 11 and a flow path cross-sectional area constituted by a gap between the downstream side surface of the collision plate 12 and the downstream end face of the housing cylinder part 11; Both are set to be substantially equal to or larger than the cross-sectional area of the combined flow path 1.

  The joint channel 1 and the mixing chamber 10 are configured to have a circular cross section with a common central axis. The mixing chamber 10 is provided with disc-shaped vertical plates 10b and 10c, and expands stepwise at the vertical plates 10b and 10c. The diameter is reduced. The collision plate 12 fixed in the housing cylinder portion 11 is provided concentrically with the mixing chamber 10.

With such a configuration, the entire amount of the fluid flowing through the combined flow path 1 collides with the collision plate 12, and a part of the collided fluid rebounds to generate a vortex and the fluid is agitated.
In addition, most of the fluids that have collided change the flow direction, flow in the centrifugal direction along the collision plate 12, and flow to the edge 13. Directional flow occurs. And this backflow collides with the fluid newly sent sequentially from the combined flow path 1, and stirring and mixing by this collision are performed.

  The fluid leaking from the edge portion 13 passes through the gap between the outer peripheral surface of the edge portion 13 and the housing cylinder portion 11 and the gap between the downstream side surface of the collision plate 12 and the downstream end face of the housing cylinder portion 11. The flow flows downstream, but the flow is merged on the downstream side of the collision plate 12, and stirring and mixing are performed by this merge.

  And the discharge path 2 is provided in the downstream from the mixing chamber 10 provided in the said combined flow path 1, The emulsified composition emulsified by stirring and mixing from this discharge path 2 is obtained. The combined flow path 1 forms a circulation flow path 5 having a circulation pump P as shown in the drawing, and the raw material stirred and mixed by the mixing chamber 10 by the switching valve 3 including a pair of valves 3a and 3b. Is mixed and re-mixed in the mixing chamber 10, and is discharged from the discharge passage 2 when mixing is sufficient. The pump P also serves as the pump P1.

  By using such an emulsifying device, an emulsion can be stably obtained even if the average particle size is 3 μm or less.

(Optimization of oil droplet diameter)
Using the emulsifying device described with reference to FIG. 1, oil droplets having an average particle diameter of less than 0.5 μm (sample A), 1 to 3 μm (sample B), and 5 to 15 μm (sample C) are prepared. 15-50 micrometers (sample D) were prepared using the D phase method used more, and the emulsion AD, the utilization degree of microorganisms, a residual degree, and construction appropriateness were compared regarding the said samples AD. The results are shown in FIG.

The results will be described for each comparison item with reference to FIG.
(1) Emulsification stability It was summarized whether or not it can be stably emulsified and whether or not the emulsified state can be stably maintained.
The following can be said.
a, It becomes unstable as the average particle size of the oil droplets increases.
b. When the average particle size of the oil droplets is 3 μm or less, it is possible to maintain a stable emulsified state for a long period of 3 months or more.
Therefore, it can be said that an average particle size of 3 μm or less is appropriate.
(2) Degree of utilization of microorganisms The degree to which microorganisms use oil droplets as nutrients is summarized.
The following can be said.
a, when the average particle size is smaller than 0.5 μm, since the average particle size is smaller than the microorganism, the oil droplets of the emulsion enter the gaps of the soil smaller than 1 μm where the microorganisms involved in purification cannot enter, Not all oil droplets can be used effectively as a nutrient.
b. When the average particle size is 1 to 3 μm, the average particle size is substantially the same as that of microorganisms, so that microorganisms are easily attached and oil droplets can be effectively used as a nutrient component.
c, when the average particle size is 5 to 15 μm, and further 15 to 50 μm, it is considered that the ease of attachment of microorganisms to oil droplets is not much different from the case where the average particle size is 1 to 3 μm. Since the surface area is small, the degree of utilization as a nutrient component decreases.
Therefore, it can be said that an average particle size of 1 to 3 μm is appropriate.
(3) Remaining degree The degree of remaining and remaining in the soil after pouring into the soil was summarized.
From the viewpoint of emulsification stability and adsorption to the soil gap, the time of remaining and staying as oil droplets in the ground water of the soil is the longest when the average particle size is 1 to 3 μm, and the diffusion region in the soil is large, Wide range of influence as a nutrient.
(4) Proper construction The ease of construction, such as injection and sample collection, was summarized.
When oil droplets are as large as 15 μm or more, the oil is easily separated in the groundwater in the soil. Therefore, equipment that contacts the groundwater is contaminated with oil when sampling the groundwater. Therefore, oil adheres to the equipment and workability deteriorates.

  From the above, it can be said that the optimum particle diameter of the oil droplets is 1 to 3 μm.

(Preparation of sample 1)
Using the emulsifier shown in FIG. 1, 60.0 parts of soybean oil as a raw material, 5% polyglycerin fatty acid ester of oil (soybean oil) as a nonionic surfactant, 37 parts by weight of water, Was stored in tank T1, and soybean oil and polyglycerin fatty acid ester were stored in tank T2 and mixed with stirring. Then, the liquid obtained by stirring and mixing in the tank T2 is merged with the water circulating between the mixing chamber 10 and the pump P in the combined flow path 1, mixed in the mixing chamber 10, and the oil droplets are mixed. An oil-in-water emulsion (sample 1) having an average particle diameter of 1 μm was obtained.

(Preparation of sample 2)
1 is used as a raw material, 60.0 parts of soybean oil as a raw material, 3% polyglycerin fatty acid ester of fats and oils as a nonionic surfactant, and 2% of fats and oils as an anionic surfactant. % Of fatty acid potassium and 37 parts by weight of water were used. Water was stored in the tank T1, and soybean oil, polyglycerin fatty acid ester and fatty acid potassium were stored in the tank T2 and mixed. Then, the liquid obtained by stirring and mixing in the tank T2 is merged with the water circulating between the mixing chamber 10 and the pump P in the combined flow path 1, mixed in the mixing chamber 10, and the oil droplets are mixed. An oil-in-water emulsion (sample 2) having an average particle size of 1 μm was obtained.

(Preparation of comparative sample)
For reference, using the conventional D phase method, using 60.0 parts by weight of soybean oil, polyglycerin fatty acid ester of 5% by weight of fat and oil as the nonionic surfactant, and 37 parts by weight of water, After adding 6 parts by weight of water, stirring and mixing, then adding soybean oil while stirring, and adding 31 parts by weight of water after homogenization, an oil-in-water emulsification with an average particle size of oil droplets of 15 μm A product (comparative sample) was obtained.

(Comparison)
At the site where the sandy silt layer is contaminated with organochlorine compounds, the oil-in-water emulsions of Sample 1, Sample 2, and Comparative Sample are injected 50 times diluted with water, and then groundwater is collected periodically. The appearance of groundwater and the appearance of oil particles in the groundwater were examined by microscopic observation. The results are shown in FIG.

As shown in FIG. 3, 7 days after the injection, Sample 1 and Sample 2 were milky white in appearance and no oil was seen, but the comparative sample was milky in appearance and a small amount of oil film was seen. Moreover, although the oil particle was maintaining about 1 micrometer in the sample 1 and the sample 2, the particle | grains of 20-30 micrometers were seen by the comparative sample.
Furthermore, 14 days after injection, Sample 1 and Sample 2 were milky white in appearance and no oil was seen, but the comparative sample was milky in appearance and a small amount of oil film was seen. In addition, the oil particles were maintained at about 1 μm in the samples 1 and 2, and the adhesion of microorganisms was observed, but in the comparative sample, particles of 20 to 30 μm were observed, and the adhesion of microorganisms was partially observed.
From the above, the oil-in-water emulsions of the present invention of Sample 1 and Sample 2 are superior in stability in groundwater as compared with conventional oil-in-water emulsions of comparative samples, and the microorganisms in groundwater It can be said that it is easy to work as nutrition.

(Application example on site)
At the site where the sandy silt layer was contaminated with organochlorine compounds, after injecting Sample 1 diluted 50 times with water, groundwater was collected periodically, and tetrachlorethylene (organochlorine compound) was collected using gas chromatography. PCE), trichlorethylene (TCE), and dichloroethylene (cis-DCE) concentrations are quantified, and the redox potential (ORP) is measured to understand the habitat of microorganisms. The total organic carbon content (TOC) was examined.
The results are shown in FIG.

  As shown in FIG. 4, after the sample 1 was injected into the site, the OPR gradually decreased and shifted to a reduced state. As a result, organochlorine compounds were decomposed by anaerobic microorganisms, and PCE decreased to a value with no problem about two months after injection. Further, cis-DCE generated by decomposition in the order of PCE → TCE → cis-DCE also showed no problem in about 4 months after injection. On the other hand, even after about 5 months after injection, it was found from the ORP and TOC values that the anaerobic atmosphere was maintained and the effect of the nutrient was maintained.

  In addition, all the oil droplet average particle diameters in this example were obtained by diluting the emulsion 50 times with water and then photographing the field of view with a microscope equipped with a 100-times eyepiece to determine the average particle diameter of the oil droplets. It is.

  As a soil and groundwater purification agent that can sufficiently purify pollutants because the oil droplets are sufficiently small in particle size, have excellent diffusibility in the soil, and can reach the soil and groundwater evenly. Can be used.

DESCRIPTION OF SYMBOLS 1 Combined flow path 2 Discharge path 3 Switching valve 10 Mixing chamber 11 Housing cylinder part 12 Colliding plate 13 Edge part T1, T2 Tank C1, C2 Raw material supply path P, P1, P2 Pump

Claims (5)

In soil, groundwater purification agent that activates microorganisms present in either or both of contaminated soil and groundwater to decompose pollutants,
It is composed of an emulsion obtained by emulsifying liquid oil and fat, a surfactant of 0.3 to 10% by weight of the liquid oil and fat, and water into an oil-in-water type, and has an average particle size of oil droplets of 1 to 3 μm. Characteristic soil and groundwater purification agent. In soil, groundwater purification agent that activates microorganisms present in either or both of contaminated soil and groundwater to decompose pollutants,
An emulsified product obtained by emulsifying liquid oil and fat, a surfactant of 0.3 to 10% by weight of the liquid fat and oil, a polysaccharide of 20 to 300% by weight of the surfactant weight, and water into an oil-in-water type. A soil and groundwater purifying agent characterized by comprising an oil droplet having an average particle diameter of 1 to 3 μm.   The soil or groundwater purifier according to claim 1 or 2, wherein the surfactant is a nonionic surfactant.   The soil according to claim 1 or 2, wherein the surfactant is a mixture of a nonionic surfactant and an anionic surfactant in an amount of 20 to 300% by weight based on the weight of the nonionic surfactant. , Groundwater purifiers.   The said liquid fats and oils are mix | blended 20 to 80weight% in the said emulsion, The purification | cleaning agent for soil and groundwater of Claim 1 or 2 characterized by the above-mentioned.

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