TWI524914B - Composition for microbiological use - Google Patents

Description

Microbial composition

The present invention relates to a microorganism composition for decomposing organic chlorine compounds in soil and groundwater by microorganisms to purify soil and groundwater, and to inject into soil and groundwater.

The soil and groundwater contaminated by chemical substances are not only in the human world, but also have a problem of balance and destruction in all aspects of the biological world. Therefore, from the perspective of environmental protection, countermeasures must be taken anyway. Moreover, the placement of contaminated soil and groundwater is also related to the field of human activities, so it is necessary to take countermeasures from an economic point of view.

Previously, various methods such as lime method, iron powder method, soil excavation replacement method, soil moisture purification method, and biological rejuvenation method have been proposed for purifying soil and groundwater contaminated with chemical substances. Soil and groundwater pollution, many cases will expand into a wide range, and the method of replacing the soil itself, the scale and funding are extremely large.

The biological rehabilitative method is considered to be one of the appropriate methods for economically purifying soil and groundwater in situ without the need for large-scale engineering. The method is a method for decomposing a chemical substance of a pollutant by aerobic or anaerobic microorganisms in soil and groundwater.

For example, microorganisms of the genus Clostridium can decompose organic substances in an anaerobic environment and decompose into acetic acid or the like. Hydrogen can be released during this process. The hydrogen can also replace chlorine of an organochlorine-based compound of chloroform, dichloromethane, dichloroethane or trichloroethane, thereby purifying such chemicals. That is, the reduction reaction of hydrogen generated in an anaerobic environment can dechlorinate the organochlorine-based compound and purify the chemical substance.

The group of substances which can provide the generated hydrogen as described above is called a hydrogen supply body, and a substance group which is activated by the microorganisms and which can become a hydrogen supply body (hereinafter referred to as "nutrition source") is injected into the soil and groundwater. The method in . However, when such a nutrient source is excessively injected, there is a concern that it spreads to a portion other than the contaminated site and secondary pollution. For this reason, for example, Patent Document 1 discloses a linear fatty acid in a granular form and a linear fatty acid mixed in glycerin, which is a composition that is less likely to move from an injection site.

However, it is known that microorganisms are inactivated under a high concentration of nutrient sources, and are thus extremely diluted with nutrient sources and sent to soil and groundwater. Moreover, when the nutrient source is close to the natural product, the toxicity can be reduced and the need to worry about secondary pollution can be reduced. Under such circumstances, it has been proposed that it is a method of supplying a wide range of nutrient sources from a pit well because it is a solid matter and a colloidal shape that does not move in an embedding place, and is not as low in viscosity and can diffuse in soil and groundwater.

Patent Document 2 discloses a technique in which a nutrient source whose main body is sorbitol is diluted to 2000 ppm and then sent to soil and groundwater to decompose an organochlorine compound by microorganisms. More specifically, the nutrient source of sorbitol 60%, glycerol 10%, anion 2%, and water 28% is diluted to 2000 ppm and then sent to soil and groundwater to diffuse. At the end of the diffusion, the carbon concentration in the nutrient source has been diluted to about 100 ppm, so for microorganisms, it has become common with chemicals. The concentration of ingestion. Therefore, the decomposition of the chemical substance can be promoted.

In Patent Document 3, it is disclosed that a non-ionic surfactant is added so that a diluted nutrient source can be well diffused in the soil. The nutrient source is a polyol and a surfactant, and the polyhydric alcohol is selected from the group consisting of: sorbitol, mannitol, xylitol, 62 to 68 parts by weight, and 8 to 10 parts by weight. The glycerin, the aforementioned surfactant, is composed of 1 to 5 parts by weight of a nonionic surfactant, and 22 to 25 parts by weight of water.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Patent Laid-Open Publication No. 2002-370085 (Patent No. 3746726)

[Patent Document 2] Patent Laid-Open No. 2009-11939 (Patent No. 5023850)

[Patent Document 3] Patent License No. 5,587,453

The nutrient source (the composition for microorganisms) having the composition of Patent Document 3 can exhibit a predetermined effect in practical use. The nutrient source is prepared in advance at the factory, and then loaded into an 18-liter tank (the so-called "one bucket"; later referred to as "transport container"). Since soil purification takes weeks to months, the handling containers loaded with nutrient sources are mostly placed in the wild.

As a result, the nutrient source is hardened in the carrying container, which causes difficulty in taking out the carrying container.

In view of the above problems, the present invention provides a composition (nutrient source) for microorganisms which does not solidify in a transport container even when placed in the field.

More specifically, the composition for microorganisms of the present invention is a microbial composition capable of purifying an organic chlorine compound in soil or groundwater, and is selected from the group consisting of sorbitol and mannitol. A triol, a nonionic surfactant, and water, and characterized in that the sugar alcohol content is less than 6 times that of the glycerin.

According to the composition for a microorganism of the present invention, it does not solidify even if it is repeatedly subjected to thermal shock in the transport container. Therefore, it is not troublesome to manage until after being used on site.

[Embodiment of the Invention]

Hereinafter, the composition for microorganisms according to the present invention will be described. In the following description, the embodiments and examples of the present invention are exemplified, but the present invention is not limited to the following description. The following embodiments may be modified without departing from the main concept of the invention.

The composition for a microorganism according to the present invention contains a material for activating microorganisms in soil and groundwater, and is intended to be diffused by an injection site. Therefore, it is a liquid and has a low viscosity. Moreover, due to the purpose of the present invention It is used in microorganisms in the soil and groundwater in a state of high dilution, and therefore must be water-soluble. Moreover, since the purpose is to purify the soil and groundwater, it is also necessary to have the function of a nutrient source.

In terms of such materials, sorbitol of a polyol sugar alcohol is suitable for use. However, mannitol can also be used. Therefore, sorbitol will be described below.

In order to keep the water-diluted sorbitol in the soil and groundwater, mix the moisturizer. In terms of a humectant, a trihydric alcohol glycerol is suitable for use. Moreover, glycerol itself can also be a source of nutrients for microorganisms. In addition, ethylene glycol is also used to lower the freezing point, so it can be used as an antifreeze. This feature can be used when purifying soil and groundwater in low temperature locations.

Further, since it is intended to be stored in the field and not solidified, the composition for microorganisms before dilution is further contained in a ratio of 1/6 or more of sorbitol to glycerin. In the examples described later, it is further shown that when the sorbitol of the polyol is placed at a high concentration of 60% by mass or more, the temperature of the surroundings is changed, and crystal nucleation crystals appear in the conveyance container. Further, there is a case where crystallization occurs around such a crystal, and thus solidification is carried out.

However, this phenomenon can be avoided by reducing the concentration or increasing the content of glycerol. Therefore, in addition to the mixing ratio of sorbitol and glycerin, the content of the sorbitol is preferably 53% by mass or more and 58% by mass or less.

The composition for a microorganism according to the present invention may be contained in a ratio of about 40% by mass or less. Basic aspects of nutrient sources do not require water. However, there is also a need to use it in concentration adjustment of nutrient sources and the like. Furthermore, water can also be used as the remainder of sorbitol, glycerol, and other additives.

Furthermore, it is preferred that the water used is subjected to sterilization treatment. In the water Contains bacteria such as water mold. Sorbitol is also a source of nutrients for such microorganisms. Therefore, when bacteria are contained, the problem of spoilage of the microorganisms may also occur during storage.

At the same time, the sterilization treatment can be boiled, and ultraviolet radiation or the like can also be applied. Moreover, pure water and ultrapure water are originally free of bacteria and can therefore be used.

The nutrient source may also contain a nonionic surfactant. Surfactant, when the nutrient source is injected into the soil and groundwater, can reduce the surface energy of the soil, thus making the nutrient source easy to wet the soil. As a result, due to the effect of the capillary phenomenon, the nutrient source can be easily diffused in the soil and groundwater. A nonionic surfactant that exhibits interfacial activity regardless of the pH of the liquid.

Therefore, nonionic surfactants do not depend on the pH of the soil and groundwater. In the soil and groundwater, it is also easy to obtain an anaerobic environment, so that the organic matter is decomposed by anaerobic gas, and the soil tends to be acidic. That is, in such an environment, the microorganism composition can be diffused as long as it is a nonionic surfactant.

For nonionic surfactants, polyoxyethylene alkyl ether polyoxyethylene lauryl ether, polyoxyethylene hexadecyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, Polyoxyethylene higher alcohol ether, polyoxyethylene myristyl ether, polyoxyethylene distyrenated phenyl ether, etc., sorbitan fatty acid ester of sorbitan monolaurate, sorbitan monopalmitate, Sorbitan monostearate, sorbitan monooleate, sorbitan distearate, polyoxyethylene sorbitan ester polyoxyethylene sorbitan monocoagulate, poly Oxyethylene sorbitan laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan Triisostearate, polyoxyethylene sorbitan monooleate, tetra oil Acid polyoxyethylene sorbitol ester and the like. Among them, polyoxyethylene alkyl lauryl ether is preferred.

Meanwhile, according to the composition for microorganisms of the present invention, a pH buffer may be further added. The pH buffer may be added in an amount of 1 to 4 parts by weight in total. When adding a pH buffer, the ratio to other ingredients must be adjusted appropriately.

The pH buffer which is suitably used may, for example, be a lactic acid-based buffer, a citric acid-based buffer, a phosphate-based buffer, or an acetic acid-based buffer. Thus, 1 to 4 parts by weight may be added.

The reason for using a pH buffer is as follows. A microbial composition as a nutrient source activates microorganisms in soil and groundwater when injected into soil and groundwater. However, since the activated microorganisms undergo anaerobic decomposition, organic acids such as acetic acid are formed, and the pH in the soil and groundwater is lowered. Microbial activity is inhibited when the pH in the soil and groundwater is excessively lowered. In other words, when the composition for microorganisms is injected into the soil and the groundwater, a period in which decomposition of the organochlorine compound or the like is not performed is formed for a certain period of time after the injection. This is called "purification stagnation period".

The pH buffer can reduce the pH by a certain amount of an organic acid such as acetic acid, and therefore, the "purification stagnation period" due to an excessive decrease in pH can be suppressed. And therefore, there is no "purification stagnation period". As a result, the advantages of shortening the period required for soil and groundwater purification can be achieved.

Example

The following shows an example of the composition for microorganisms according to the present invention. In order to confirm the crystallization, the samples shown in Table 1 were prepared, and each was placed in a 5-tank carrying container, and then subjected to a temperature change in a constant temperature test chamber. Handling container Often 18 liters of cans are made of iron. The inner wall is not particularly treated with a protective film or a protective layer. Thereafter, the mixture was subjected to a thermal shock cycle for 30 hours at 12 ° C for 12 hours and at 15 ° C for 12 hours in a constant temperature test chamber. Furthermore, in the thermostat, the temperature change must be about 60 minutes.

Sample 1 was 65 mass% of sorbitol, 10 mass% of glycerol, 2 mass% of nonionic surfactant, and 23 mass% of water. As the nonionic surfactant, polyoxyethylene lauryl ether is used. Moreover, the water system uses boiled tap water. All samples were the same after this. Sample 1 was crystallized in 5 cans of 5 cans. The results are shown in Table 1.

Sample 2 was 60% by mass of sorbitol, 10% by mass of glycerin, 2% by mass of nonionic surfactant, and 28% by mass of water. Sample 2 was crystallized in 5 cans of 5 cans. The results are shown in Table 1.

Sample 3 was 59% by mass of sorbitol, 10% by mass of glycerin, 2% by mass of nonionic surfactant, and 29% by mass of water. Sample 3 did not crystallize in any of the five cans. The results are shown in Table 1.

Sample 4 was 58% by mass of sorbitol, 10% by mass of glycerin, 2% by mass of nonionic surfactant, and 30% by mass of water. Sample 4 did not crystallize in any of the five cans. The results are shown in Table 1.

Sample 5 was 55 mass% of sorbitol, 10 mass% of glycerol, 2 mass% of nonionic surfactant, and 33 mass% of water. The results are shown in Table 1. Sample 5 did not crystallize in any of the five cans. The results are shown in Table 1.

Referring to Table 1, when sorbitol exceeded 59% by mass, more than half of the 5 cans of each sample were crystallized. However, in terms of 58% by mass, no crystallization occurred in 5 cans. It is widely known as sorbitol crystals, which appear when cooled to a very low temperature at one degree and then slowly rise in temperature. However, such temperature treatment is not performed here.

Therefore, it is difficult to think that crystallization of the crystal nucleus is caused by the formation of pure sorbitol crystals. Perhaps, it is necessary to form a minute impurity which is mixed in the preparation, and a nucleation crystal is generated in a wall interface between the wall of the carrier and the liquid interface of the microorganism composition, whereby crystallization occurs. Here, the phenomenon in which the microorganisms loaded into the transport container are solidified is called crystallization.

Next, the content of glycerol was changed by a test in which 60% by mass of sorbitol crystallization occurred and 58% by mass which did not occur. The composition of each sample is shown in Table 2.

Sample 6 was 60% by mass of sorbitol, 7% by mass of glycerin, 2% by mass of nonionic surfactant, and 31% by mass of water.

Sample 7 was 58% by mass of sorbitol and 7% by mass of glycerin. The ionic surfactant was 2% by mass and the water was 33% by mass.

Sample 8 was 60% by mass of sorbitol, 8% by mass of glycerin, 2% by mass of nonionic surfactant, and 30% by mass of water.

Sample 9 was 58% by mass of sorbitol, 8% by mass of glycerin, 2% by mass of nonionic surfactant, and 32% by mass of water.

Sample 10 was 60% by mass of sorbitol, 9% by mass of glycerin, 2% by mass of nonionic surfactant, and 29% by mass of water.

Sample 11 was 58% by mass of sorbitol, 9% by mass of glycerin, 2% by mass of nonionic surfactant, and 31% by mass of water.

Sample 12 was 60% by mass of sorbitol, 11% by mass of glycerin, 2% by mass of nonionic surfactant, and 27% by mass of water.

Sample 13 was 58% by mass of sorbitol, 11% by mass of glycerin, 2% by mass of nonionic surfactant, and 29% by mass of water.

Sample 14 was 60% by mass of sorbitol, 12% by mass of glycerin, 2% by mass of nonionic surfactant, and 26% by mass of water.

Sample 15 was 58% by mass of sorbitol, 12% by mass of glycerin, 2% by mass of nonionic surfactant, and 28% by mass of water.

Sample 16 was 65 mass% of sorbitol, 11 mass% of glycerol, 2 mass% of nonionic surfactant, and 22 mass% of water. The results are shown in Table 2.

Referring to Table 2, among the samples 12 and 14 (60% by weight of sorbitol) which were considered to be crystallized as a result of Table 1, none of the five cans were crystallized. Further, in the case of the samples 7, 9, and 11 (the amount of sorbitol 58%) which should not be crystallized, crystallization occurred in 1 or 2 cans in 5 cans. At the same time, it is judged that the transport container in which crystallization does not occur, and a considerable amount of agglomeration is also generated therein.

From the above results, it can be concluded that the presence or absence of crystallization is not solely due to the concentration of sorbitol. Therefore, the ratio of sorbitol to glycerol was observed again. In Table 2, the ratio of sorbitol to glycerol (expressed as "S:G") is shown.

Comparing the ratio of the sorbitol to glycerol, it is expected that crystallization will occur in a ratio of 6 to 1. Therefore, in the sample 16, the sample 1 shown in Table 1 (sorbent alcohol: 65 mass%) was tested, and 11 mass% of glycerin was added to the composition. In Sample 16, the ratio of sorbitol to glycerol was 5.9 to 1. As shown in Table 2, in the sample 16 , even when sorbitol was 65% by mass and the ratio of glycerol to 6 times or less, crystallization of 5 cans in 5 cans did not occur.

As described above, in the composition for microorganisms, the ratio of sorbitol to glycerin is made smaller than 6-1 (reducing sorbitol), and crystallization can be avoided.

Since sorbitol is very similar to mannitol, the same phenomenon occurs with mannitol. Therefore, based on the understanding obtained by the sorbitol in the above experiment, the presence or absence of crystallization was carried out in the composition of Table 3.

Sample 17 was 60% by mass of mannitol, 7% by mass of glycerin, 2% by mass of nonionic surfactant, and 31% by mass of water. The ratio of mannitol to glycerol (expressed as "M:G" in Table 3) was 8.5:1.

Sample 18 was 58% by mass of mannitol, 9% by mass of glycerin, 2% by mass of nonionic surfactant, and 31% by mass of water. Mannitol and glycerol The ratio (indicated by "M:G" in Table 3) is 6.4:1.

Sample 19 was 60% by mass of mannitol, 11% by mass of glycerin, 2% by mass of nonionic surfactant, and 27% by mass of water. The ratio of mannitol to glycerol (expressed as "M:G" in Table 3) was 5.4:1.

Sample 20 was 58% by mass of mannitol, 11% by mass of glycerin, 2% by mass of nonionic surfactant, and 29% by mass of water. The ratio of mannitol to glycerol (expressed as "M:G" in Table 3) was 5.3:1.

Sample 21 was 65 mass% of mannitol, 11 mass% of glycerol, 2 mass% of nonionic surfactant, and 22 mass% of water. The ratio of mannitol to glycerol (expressed as "M:G" in Table 3) was 5.9:1.

The results are shown in Table 3. Referring to Table 3, when the ratio of mannitol to glycerol was less than 6:1 (reducing mannitol or increasing glycerol), crystallization did not occur. However, in sample 18, crystallization occurred in 4 cans in 5 cans. In this case, in the case of sorbitol, the composition ratio is the same as that of the sample 11, and in the case of sorbitol, it is confirmed that the crystallization is one tank in 5 cans. Therefore, it can be said that mannitol is more susceptible to crystallization than sorbitol.

The embodiment shown next is to determine the purification effect of the soil of the composition for microorganisms in the present invention. The examples were carried out on site contaminated with tetrachloroethane. The aquifer is 2.0 to 12.2 m from the surface of the soil. At the same time, the concentration of tetrachloroethane in the groundwater is about 0.8 mg/L. The test system is provided with a 100 mm diameter injection pit, and the microbial composition is injected into the pit well connection tube.

At the same time, an observation pit was set up 3m from the injection well, and the concentration of tetrachloroethane, sorbitol concentration and pH in the groundwater was regularly monitored. Further, the injection pit and the observation pit which are injected into the composition for each microorganism are sufficiently isolated so as not to affect the composition of each microorganism.

The composition for each of the microorganisms to be injected was an aqueous solution diluted to 2000 ppm, and after continuous injection for 9.0 L/min for 7 days, only the monitoring was continued.

In Example 1, 52% by mass of sorbitol, 9% by mass of glycerin, 2% by mass of nonionic surfactant, and 37% by mass of water were mixed. The ratio of sorbitol to glycerol is "5.7:1". Meanwhile, as the nonionic surfactant, polyoxyethylene lauryl ether is used. The water is boiled in normal tap water for 10 minutes and then cooled to 25 ° C for use. The composition and results are shown in Table 4.

In addition, the "G ratio" in Table 4 is "the ratio of glycerol", and shows the ratio of the sugar alcohol when glycerol is 1. Meanwhile, "S" in Table 4 indicates sorbitol, and "M" indicates mannitol.

In Example 2, 55 mass% of sorbitol, 10 mass% of glycerol, 2 mass% of nonionic surfactant, and 33 mass% of water were mixed. The ratio of sorbitol to glycerol is "5.5:1". Example 3 is 58% by mass of sorbitol, 10% by mass of glycerin, 2% by mass of nonionic surfactant, and 30% by mass of water. mixing. The ratio of sorbitol to glycerol is "5.8:1".

In Example 4, 52% by mass of mannitol, 9% by mass of glycerin, 2% by mass of nonionic surfactant, and 37% by mass of water were mixed. The ratio of mannitol to glycerol is "5.7:1".

In Example 5, 55 mass% of mannitol, 10 mass% of glycerol, 2 mass% of nonionic surfactant, and 33 mass% of water were mixed. The ratio of mannitol to glycerol is "5.5:1". In Example 6, it was mixed with 58% by mass of mannitol, 10% by mass of glycerin, 2% by mass of nonionic surfactant, and 30% by mass of water. The ratio of mannitol to glycerol is "5.8:1".

All of the microbial compositions of the examples had a ratio of sugar alcohol to glycerol of 6:1 or less (reduced sugar alcohol). The composition and results are shown in Table 4. Further, in the case of the present embodiment, the composition for microorganisms filled in the transport container was placed in the field for a period of one month or more in the test site, and no one tank was crystallized.

Reference Table 4 shows the decomposition rate obtained by the concentration of tetrachloroethane before the test and the concentration after 30 days, and is expressed by %. At the same time, the sugar concentration (mg/L) after 7 days at the sampling site of 3m from the pit was also shown.

In Examples 1 to 6, tetrachloroethane was decomposed by 95% or more at a position of 3 m from the pit. Moreover, the concentration of sorbitol after 7 days at the sampling site of 3 m from the well was also more than 800 mg/L. From this, it is understood that the composition of the composition for microorganisms according to the present invention can improve the wettability of the soil surface even in a state of high dilution, and cause decomposition of tetrachloroethane when diffused in the soil.

[The possibility of industrial use]

The composition for microorganisms according to the present invention can be utilized as a nutrient source when it is utilized by microorganisms in soil and groundwater to decompose/purify organic chlorine compounds in soil and groundwater.

Claims (2)

A composition for microorganisms, which is a microorganism composition for purifying an organic chlorine compound in soil or groundwater, and is selected from any one or more of sugar alcohols, glycerol, and nonionic interfaces selected from the group consisting of sorbitol and mannitol. The content of the sugar alcohol is less than 6 times that of the glycerin, and the sugar alcohol is 53% by mass or more and 58% by mass or less in the microorganism composition. The composition for microorganisms according to claim 1, wherein the nonionic surfactant is polyoxyethylene lauryl ether.