JP2002143830A - Method for decomposing and removing pollutant by microorganism and additive for decomposition of pollutant to be used for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly decompose hardly decomposable polycyclic aromatic hydrocarbons such as tetracyclic pyrene and pentacyclic benzopyrene. SOLUTION: In the method for decomposing and removing pollutants by microorganisms, compost of sheep feces is first used as a compost and subjected to secondary fermentation with wooden material. As for the wooden material, for example, sawdust can be used. Then the secondary fermented substance obtained by fermenting the compost of sheet feces with sawdust as the wooden material is added and mixed to the oil-polluted soil as a polluted material containing polycyclic aromatic hydrocarbons(PAH) such as phenanthrene, anthracene, fluoranthene, pyrene, chrysene or the like as the pollutants.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for decomposing and removing contaminants by microorganisms and an additive for decomposing contaminants used therein.

[0002]

2. Description of the Related Art Recently, a technique called bioremediation, in which contaminants are decomposed and rendered harmless by microorganisms, has attracted attention.

[0003] Bioremediation is a method of decomposing and detoxifying contaminants by utilizing the decomposing ability of microorganisms such as bacteria and fungi. -By improving the activity of microorganisms by adjusting the environment such as nutrition and ventilation, it is possible to decompose pollutants more efficiently than in the natural state.

[0004] Such bioremediation does not use any chemical agent such as physical treatment or chemical treatment, so it is low in cost and high in safety, and it is expected that its application will be further expanded in the future.

[0005]

Here, for example, in a case where soil contaminated with crude oil is to be purified by bioremediation, various hydrocarbon compounds having about 5 to 40 carbon atoms, which are the main components of crude oil, have a molecular Depending on the type of structure, paraffins, so-called aliphatic hydrocarbons such as olefins, and aromatic hydrocarbons are roughly classified, and among these, aliphatic hydrocarbons and aromatic hydrocarbons having a relatively simple structure, for example, Acenaphthene, fluorene, and 3 containing two rings
Ring-containing phenanthrene, fluoranthene and the like can be relatively easily decomposed by bacteria contained in the soil, and in that sense, these substances can be classified as easily degradable hydrocarbons.

On the other hand, polycyclic aromatic hydrocarbons having a complicated structure, such as 4-ring pyrene and 5-ring benzopyrene, are said to be hardly degradable hydrocarbons. However, there has been a problem that it is not possible to sufficiently disassemble the device even if it is used.

The present invention has been made in view of the above circumstances, and is a microorganism contaminant capable of rapidly decomposing even hardly decomposable polycyclic aromatic hydrocarbons such as 4-ring pyrene and 5-ring benzopyrene. It is an object of the present invention to provide a method for decomposing and removing water and a contaminant decomposition additive used therefor.

[0008]

In order to achieve the above object, a method for decomposing and removing contaminants by microorganisms according to the present invention comprises subjecting a predetermined compost to secondary fermentation with a woody material. The secondary fermentation substance is added to and mixed with a contaminant containing a contaminant composed of a polycyclic aromatic hydrocarbon or a compound having a structure similar thereto, and the contaminant is decomposed by microorganisms.

Further, the method for decomposing and removing contaminants by microorganisms according to the present invention comprises the steps of:
It is a polycyclic aromatic hydrocarbon such as anthracene, fluoranthene, pyrene and chrysene.

In the method for decomposing and removing contaminants by microorganisms according to the present invention, the contaminants may be phenanthrene,
It is a mixture comprising a polycyclic aromatic hydrocarbon such as anthracene, fluoranthene, pyrene, chrysene and the like and an aliphatic hydrocarbon.

In the method for decomposing and removing contaminants by microorganisms according to the present invention, the compost is a sheep dung compost.

Further, the additive for decomposing pollutants according to the present invention is obtained by subjecting a predetermined compost to secondary fermentation with a woody material.

In the method for decomposing and removing contaminants by microorganisms and the additive for decomposing contaminants used therein according to the present invention, it is premised that predetermined compost is used. Almost no microorganisms produce enzymes capable of degrading polycyclic aromatic hydrocarbons or compounds similar in structure to them (considered as lignin-degrading enzymes), or even if present, they have low enzyme activity in compost, in other words, polycyclic aromatics. Compost which does not decompose to pollutants consisting of group hydrocarbons or compounds similar in structure thereto. Therefore, simply adding the compost referred to in the present invention to a contaminant containing a contaminant composed of a polycyclic aromatic hydrocarbon or a compound having a similar structure to the contaminant ensures that the contaminant contained in the contaminant is contained. Detoxification is difficult.

However, the present applicant has previously found that polycyclic aromatic hydrocarbons can be decomposed using cow manure compost, and based on this finding, polycyclic aromatic hydrocarbons can be decomposed using other composts. As a result of repeatedly conducting various experiments and studying whether hydrogen or a compound similar in structure cannot be decomposed, even if the compost has no decomposability to pollutants consisting of polycyclic aromatic hydrocarbons, such It has been found that pollutants can be decomposed.

That is, in the method for decomposing and removing contaminants by microorganisms according to the present invention and the additive for decomposing contaminants used therein, first, the above-mentioned compost is secondarily fermented with wood material.

Next, the secondary fermented substance obtained by subjecting the predetermined compost to secondary fermentation with the woody material is added to the contaminant containing the contaminant composed of the polycyclic aromatic hydrocarbon or a compound similar in structure to the polycyclic aromatic hydrocarbon. Mix.

In this way, the microorganisms proliferated in the secondary fermentation substance immediately decompose and remove polycyclic aromatic hydrocarbons or contaminants composed of compounds similar in structure to the polycyclic aromatic hydrocarbons.

This is a microorganism capable of assimilating lignin contained in woody material among microorganisms contained in compost,
In other words, the lignin-utilizing bacteria grow while decomposing and assimilating lignin in the woody material, and then, the grown lignin-utilizing bacteria produce polycyclic aromatic hydrocarbons similar in structure to lignin or compounds similar thereto. It is considered that it is decomposed.

As can be seen from the fact that sheep dung compost is fermented with grass, for example, the above-mentioned compost is previously fermented with a material other than woody material. Is particularly referred to herein as secondary fermentation.

In the present invention, the contaminant to be decomposed and removed is a polycyclic aromatic hydrocarbon or a compound similar in structure to the polycyclic aromatic hydrocarbon.

Here, the polycyclic aromatic hydrocarbon includes 4
So-called hardly decomposable polycyclic aromatic hydrocarbons such as fluoranthene, pyrene, benzoanthracene, and chrysene containing a ring, and benzofluoranthene and benzopyrene containing a five-ring are mainly used, but include three rings such as phenanthrene and anthracene. It does not exclude easily decomposable polycyclic aromatic hydrocarbons or lower polycyclic aromatic hydrocarbons.

On the other hand, compounds having a structure similar to polycyclic aromatic hydrocarbons include at least dioxins and PCB.

As described above, the contaminants to which the present invention can be applied cover a wide range. Specifically, as described above, phenanthrene, anthracene, fluoranthene, pyrene,
It is conceivable to target polycyclic aromatic hydrocarbons such as chrysene.

Here, when a pollutant in which an aliphatic hydrocarbon is mixed in addition to such a polycyclic aromatic hydrocarbon is targeted, even if the aliphatic hydrocarbon is present, the polycyclic aromatic hydrocarbon is used. It is possible to quickly decompose and remove hydrocarbons, and it is extremely effective in treating oil-contaminated soil contaminated with crude oil, for example.

The wood material may be any material as long as it contains lignin, and may have any form. For example, a sawdust-like wood material may be used. By the way, lignin is 20-
It is believed that most wood can be used as the wood material of the present invention because it is present at 30%.

As long as the contaminant contains a contaminant composed of a polycyclic aromatic hydrocarbon or a compound having a structure similar to the contaminant, the type of the contaminant is arbitrary. Oil-contaminated soil obtained by mixing polycyclic aromatic hydrocarbons and aliphatic hydrocarbons as contaminants in addition to the pollutants referred to in the present invention, industrial waste such as plastic waste, concrete waste, etc. Even when the above-mentioned contaminants are mixed, the contaminants of the present invention are included.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a method for decomposing and removing contaminants by microorganisms and an additive for decomposing contaminants used in the present invention will be described with reference to the accompanying drawings. It is to be noted that the same reference numerals are given to components and the like that are substantially the same as those in the conventional technology, and description thereof will be omitted.

In the method for decomposing and removing contaminants by microorganisms according to the present embodiment, sheep dung compost is used as a predetermined compost, and the sheep dung compost is secondarily fermented with a woody material.

As the woody material, for example, sawdust can be used.

Next, the secondary fermentation material obtained by secondary fermentation of sheep dung compost with sawdust as a woody material is converted into polycyclic aromatic hydrocarbons (PAH) such as phenanthrene, anthracene, fluoranthene, pyrene and chrysene. Add to and mix with oil contaminated soil as pollutants including as pollutants.

In this way, the microorganisms proliferated in the secondary fermentation substance rapidly decompose certain polycyclic aromatic hydrocarbons regardless of the presence or absence of aliphatic hydrocarbons.

This is because, among the microorganisms contained in the sheep dung compost, microorganisms capable of assimilating lignin contained in the woody material, that is, lignin-utilizing bacteria grow while decomposing and assimilating lignin in the woody material. Next, it is considered that this time the grown lignin-utilizing bacteria degrade polycyclic aromatic hydrocarbons similar in structure to lignin.

As described above, according to the method for decomposing and removing contaminants by microorganisms according to the present embodiment, sheep that originally have few microorganisms capable of decomposing hardly decomposable polycyclic aromatic hydrocarbons exist. Even in the case of a fecal compost, a microorganism capable of decomposing a hardly decomposable polycyclic aromatic hydrocarbon can be grown by secondary fermenting the sheep feces compost with a wooden material.

In particular, in a situation where no aliphatic hydrocarbon is present, a certain decomposition effect can be expected only with the sheep dung compost alone, but in a situation where the aliphatic hydrocarbon is mixed, the sheep dung compost alone is hardly degradable. Although it was almost impossible to decompose the cyclic aromatic hydrocarbon, according to the method for decomposing and removing contaminants by microorganisms according to the present embodiment, even when aliphatic hydrocarbons are mixed, a certain It becomes possible to rapidly decompose the hardly decomposable polycyclic aromatic hydrocarbon.

Although not specifically mentioned in the present embodiment, the secondary fermentation material obtained by secondary fermentation of sheep dung compost with woody material such as sawdust is used to add the above-mentioned contaminants to the contaminants. Since it can be degraded, the secondary fermentation material functions as an additive for decomposing pollutants.

In this embodiment, sheep manure compost is used as a compost. However, the compost of the present invention is not limited to this type of compost, but may be made of polycyclic aromatic hydrocarbon or a compound having a structure similar to that. Any compost may be used as long as it is not decomposable with respect to the pollutants.

Next, in order to confirm the method of decomposing and removing contaminants by microorganisms according to the present embodiment and the effect of the contaminant decomposing additive used therein, sheep dung compost was subjected to secondary fermentation with sawdust, which is a woody material. This was added to the polycyclic aromatic hydrocarbon and cured for a predetermined period, and the decomposition process was measured.
The outline of the experiment and the measurement results will be described below.

(Preparation of test compost)

As the test compost, two types of compost were prepared.

[0040] The first test compost is a sheep dung compost (c).
fu: 1.7E + 7 / g of bacteria and 2.4E + 6 / g of filamentous fungi were collected in a 500 ml beaker, and then 100 g of sawdust, 1.1 g of rice bran, and 10 ml of tap water were added thereto. This was cultured for 14 days at 35 ° C. (hereinafter referred to as microbial material B).

As the second test compost, the same sheep dung compost itself was used as the test compost (hereinafter, this is referred to as microbial material C).

(Experimental procedure)

Next, sea sand 1 was placed in six 500 ml flasks.
Then, 00 g of each sample was collected, each of which was covered with an aluminum foil, and then sterilized by dry heat (170 ° C., 4 hours). Next, of the six flasks, the first two flasks (flasks Nos. 7 and 10) were milled and mixed in a mortar.
50 kinds of polycyclic aromatic hydrocarbons (phenanthrene, anthracene, fluoranthene, pyrene, chrysene)
mg each (PAH concentrations of 5 types and 100
ppm) and the next two flasks (flasks Nos. 8 and 11) each contained only 1 g of lubricating oil as an aliphatic hydrocarbon.
(The concentration of the aliphatic oil is 1%), and the last two flasks (flasks Nos. 9 and 12) contain the above-mentioned five types of polycyclic aromatic hydrocarbons and the lubricating oil as an aliphatic hydrocarbon. Both were similarly added in the amounts described above.

Next, 30 g of each of the two types of microbial materials described above was added to each flask for microbial material B, and 7 g of microbial material C was added to each flask, and nutrients (sterilized Hyponex (trade name) were increased by 500 times). 20 ml of the microbial material B and 10 ml of the microbial material C were added.

Next, put 100 g of sand into each flask,
Then, each of the flasks was hardened with a cotton plug so that it became an open cure, and stirring was performed once a day in such a state,
The culture was allowed to stand at 30 ° C., and periodically sampled until a certain period of time elapses for quantitative analysis. During the stationary culture, the water content was maintained once a week by the amount of transpiration to maintain the water content, and the above-mentioned nutrients were added as appropriate.

(Experimental results)

First, the results for the microbial material B are shown in Table 1 and FIG.

[0048]

[Table 1]

As can be seen from these tables and figures, with respect to the microbial material B, remarkable decomposition progressed without waiting for 56 days except for chrysene, and the tendency was the same as in the case of PAH alone ( (A) in FIG.
+ Lubricant oil) even in the case of mixing. In particular, as can be clearly seen from Table 1, when (PAH + lubricating oil) is mixed, pyrene is 2 ppm from 43.7 ppm after 56 days, and 0.5 ppm after 112 days.
It can be seen that it has been decomposed to.

Therefore, it is considered very promising to decompose and remove oil-contaminated soil with microbial material B.

A test compost using only sheep manure compost, that is, a microbial material C is shown in Table 2 and FIG. 2 for comparison.

[0052]

[Table 2]

As can be seen from these tables and figures, the degradation progress after 56 days is almost the same as that of the microbial material B when the sheep dung compost is used alone and when only PAH is used (FIG. (A)). However, in the case of (PAH + lubricating oil) mixture (FIG. (B)), the decomposition of PAH did not progress very much even after 56 days, decomposing the hardly decomposable polycyclic aromatic hydrocarbon. The difference with the microbial material B in the ability to perform is clear.

[0054] This difference is due to the fact that sheep dung compost is made of wood-based material even though sheep dung compost originally did not have a complex microbial group that promotes the progress of PAH degradation in the presence of aliphatic hydrocarbons. It can be considered that the following fermentation resulted in the acquisition of such a complex microorganism group.

[0055]

As described above, according to the method for decomposing and removing contaminants by microorganisms and the contaminant decomposing additive used therein according to the present invention, a polycyclic aromatic hydrocarbon or a polycyclic aromatic hydrocarbon or a polycyclic aromatic hydrocarbon should be used. Even in a compost having almost no microorganisms capable of decomposing contaminants composed of similar compounds, it is possible to proliferate microorganisms capable of decomposing such contaminants by secondary fermenting the compost with woody material. .

[0056]

[Brief description of the drawings]

FIG. 1 is a graph showing the operation of a method for decomposing and removing contaminants by microorganisms according to the present embodiment.

FIG. 2 is a graph showing the operation of the method for decomposing and removing contaminants by microorganisms according to the embodiment.

Claims (5)

[Claims] Claims: 1. A predetermined compost is secondarily fermented with a woody material,
Adding the secondary fermentation substance to a contaminant containing a contaminant composed of a polycyclic aromatic hydrocarbon or a compound having a structure similar thereto and mixing the contaminant with the contaminant to decompose the contaminant with microorganisms; Decomposition and removal method. 2. The method according to claim 1, wherein the contaminants are polycyclic aromatic hydrocarbons such as phenanthrene, anthracene, fluoranthene, pyrene, and chrysene. 3. The method for decomposing and removing contaminants according to claim 1, wherein the contaminants are a mixture of polycyclic aromatic hydrocarbons such as phenanthrene, anthracene, fluoranthene, pyrene, chrysene and aliphatic hydrocarbons. 4. The method according to claim 1, wherein said compost is sheep dung compost. 5. An additive for decomposing pollutants, wherein a predetermined compost is secondarily fermented with a woody material.