JP2000254635A - Method of decomposing and removing oil-polluted soil by means of microorganisms, and oil-decomposing additive used in same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly decompose even decomposition retarding polynuclear aromatic hydrocarbon such as tetracyclic pyrene and pentacyclic benzopyrene. SOLUTION: In this method for decomposing and removing oil-polluted soil by means of microorganisms and this oil-decomposing additive used for the method, first, an additive for oil decomposition consisting essentially of compost such as cow dung compost, excrement compost, sewage sludge compost, and beer grains compost is prepared, and it is added to and mixed with oil polluted soil polluted with polynuclear aromatic hydrocarbon, in particular, so-called decomposition retardant polynuclear aromatic hydrocarbon, such as four rings containing fluorantene, pyrene, benzoanthracene, and chrysene or five rings containing benzzofluorantene, and bezopyrene. In this way, by activity of microorganisms contained in the compost, the decomposition retardant polynuclear aromatic hydrocarbon is microorganisms decomposed in a short period of time and at a high decomposition rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing and removing oil-contaminated soil by microorganisms and an oil decomposition additive used therefor.

[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] Since such bioremediation does not use any chemical agent unlike physical treatment or chemical treatment, it is expected to be low in cost and high in safety, and its application range 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-mentioned circumstances, and is an oil contamination by a microorganism capable of rapidly decomposing even hardly decomposable polycyclic aromatic hydrocarbons such as 4-ring pyrene and 5-ring benzopyrene. An object of the present invention is to provide a method for decomposing and removing soil and an additive for oil decomposition used in the method.

[0008]

In order to achieve the above-mentioned object, a method for decomposing and removing oil-contaminated soil by microorganisms according to the present invention, as described in claim 1, comprises phenanthrene, anthracene, fluoranthene, pyrene, chrysene and the like. A compost such as cow dung compost, human dung compost, sewage sludge compost, and beer refuse compost is added to and mixed with oil-contaminated soil containing polycyclic aromatic hydrocarbons to biodegrade the polycyclic aromatic hydrocarbons.

[0009] The additive for oil decomposition according to the present invention is mainly composed of compost such as cow manure, human manure compost, sewage sludge compost, and beer refuse compost.

In the method for decomposing and removing oil-polluted soil by microorganisms and the additive for decomposing oil according to the present invention,
Compost such as cow manure, human manure, sewage sludge compost, and beer ground compost is added to oil-contaminated soil containing polycyclic aromatic hydrocarbons such as phenanthrene, anthracene, fluoranthene, pyrene, and chrysene.

In this manner, the polycyclic aromatic hydrocarbon is microbial degraded by the microbial activity of the cells contained in the compost.

As the polycyclic aromatic hydrocarbon, so-called hardly decomposable polycyclic aromatic hydrocarbons such as fluoranthene containing four rings, pyrene, benzoanthracene and chrysene, and benzofluoranthene containing five rings and benzopyrene are mainly used. Targets include phenanthrene and anthracene
It does not exclude easily decomposable polycyclic aromatic hydrocarbons containing a ring or lower polycyclic aromatic hydrocarbons.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for decomposing and removing oil-polluted soil by microorganisms and an oil decomposition additive used therein according to the present invention will be described below 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 is omitted.

In the method for decomposing and removing oil-contaminated soil by microorganisms according to the present embodiment and the additive for oil decomposition used therein, first, compost such as cow dung compost, human dung compost, sewage sludge compost and beer cake compost is used as a main component. An oil decomposition additive is prepared. Specific examples of such oil decomposition additives include:
It could be composed of cow dung compost alone.

Next, the oil-decomposition additive prepared as described above is used as a so-called hardly decomposable polycyclic aromatic substance such as fluoranthene containing four rings, pyrene, benzoanthracene, and chrysene, and benzofluoranthene containing five rings and benzopyrene. Mixed with oil-contaminated soil contaminated with aromatic hydrocarbons.

In this manner, the hardly decomposable polycyclic aromatic hydrocarbon is microbially decomposed in a short period of time and at a high decomposition rate due to the activity of the microorganisms contained in the compost.

In addition, when the above-mentioned additive for oil decomposition is added, a medium and water necessary for the growth and activity improvement of the microorganism are appropriately added as necessary, and an environment suitable for the habitat of the microorganism is obtained. Also, ventilate as needed to maintain an aerobic environment.

Next, the method of decomposing and removing oil-polluted soil by microorganisms according to the present embodiment and the effect of the oil decomposition additive used therein have been confirmed by experiments, and the details thereof will be described below.

First, 50 g of sand is placed in a 500 ml flask.
And sterilize the flask with dry heat.

Next, five types of polycyclic aromatic hydrocarbons, phenanthrene, anthracene, fluoranthene, pyrene, and chrysene, were weighed in an amount of 50 mg each and ground and mixed. And mix. Here, the terminal concentration is 1
Adjust appropriately so as to be 00 ppm.

Next, 100 ml of cow dung compost (equivalent to 13 g)
And sterile MBM (Minimal Basal Medium) medium 10ml
Is added to each flask and mixed.
After 30 days, 60 days and 90 days, sampling is performed, and the polycyclic aromatic hydrocarbons in the flask are quantitatively analyzed by a known method using liquid chromatography.

Table 1 shows the composition of the MBM medium. In addition, 1.0 ml of the trace element solution shown in Table 2 was added to the MBM medium.
/ L and the pH was adjusted to 6.8-6.9 before sterilization.

[0023]

[Table 1]

[0024]

[Table 2]

The above-mentioned cow dung compost is a raw compost in a state in which microorganisms inhabit, but as a comparative control, a cow dung compost which has been sterilized in advance is used as a comparative control so that only the effect of the microbial activity can be examined. Quantitative analysis was performed as described above.

FIG. 1A is a graph showing the results of quantitative analysis when using sterilized compost, and FIG. 1B is a graph showing the results of quantitative analysis using raw compost.

From these graphs, it can be seen that polycyclic aromatic hydrocarbons were decomposed at a high decomposition rate by adding cow manure compost (raw compost) to the oil-contaminated soil. Looking at, phenanthrene is 99.7
%, Anthracene 87%, fluoranthene 97%,
It can be seen that pyrene was decomposed to 96% and chrysene to 45%. Also, in view of the low decomposition rate (high residual rate) of the sterilized compost, it can be concluded that the above-mentioned remarkable decomposition action is due to the microbial activity in the compost. In addition, the quantitative analysis of the other sample (the result is omitted) shows almost the same numerical value as the result described above, and the reproducibility was confirmed.

Next, an experiment was carried out on a compost other than cow manure compost in the same procedure as described above, and the effect of decomposing polycyclic aromatic hydrocarbons was demonstrated. Table 3 shows the results.

[0029]

[Table 3]

As can be seen from the table, although the decomposition performance for individual hydrocarbons differs depending on the type of compost, in general, all the composts show a high decomposition rate (100%) for polycyclic aromatic hydrocarbons. -Residual ratio shown in the same table). In addition, beef manure compost has an extremely excellent decomposing effect on polycyclic aromatic hydrocarbons other than chrysene, and beer dregs on chrysene, which is a hardly decomposable polycyclic aromatic hydrocarbon. It can also be seen that compost and manure compost have an excellent decomposition action.

As described above, according to the method for decomposing and removing oil-polluted soil by microorganisms and the additive for decomposing oil used in the present embodiment, the easily decomposable polycyclic aromatic containing three rings such as phenanthrene and anthracene. Microorganisms can be decomposed in a short period of time and at a high decomposition rate not only for aromatic hydrocarbons but also for hardly decomposable polycyclic aromatic hydrocarbons such as fluoranthene, pyrene, and chrysene containing four rings.

This is because a group of microorganisms present in cow manure, human manure compost, sewage sludge compost, beer refuse compost, and the like produce a large amount of a decomposing enzyme capable of decomposing polycyclic aromatic hydrocarbons, for example, lignin peroxidase. It is presumed.

Such a compost can be obtained at low cost and has no fear of adversely affecting the natural environment and the ecosystem. Therefore, it is most suitable as an additive for oil cracking. It is possible to decompose polycyclic aromatic hydrocarbons contained in the oil-contaminated soil, in particular, hardly decomposable polycyclic aromatic hydrocarbons in a short period of time and at a high decomposition rate, and to treat the treated soil for agriculture. It can also be diverted as soil for use.

In the present embodiment, application to so-called hardly decomposable polycyclic aromatic hydrocarbons is premised. However, the method for decomposing and removing oil-polluted soil by microorganisms according to the present invention and the oil decomposition additive used therefor are: The present invention is also applicable to easily decomposable polycyclic aromatic hydrocarbons containing three rings, and in this case, it is needless to say that a remarkable decomposition action can be expected as described above.

[0035]

As described above, according to the method for decomposing and removing oil-polluted soil by microorganisms according to the present invention and the additive for decomposing oil, the easily degradable polycyclic ring containing three rings such as phenanthrene and anthracene. Microorganisms can be decomposed in a short period of time and at a high decomposition rate, not only for aromatic hydrocarbons but also for hardly decomposable polycyclic aromatic hydrocarbons containing four rings, such as fluoranthene, pyrene and chrysene.

[0036]

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graph showing a method for decomposing and removing oil-contaminated soil by microorganisms according to the present embodiment and the effect of an oil decomposition additive used therein.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C12N 1/00 C12N 1/00 R // C09K 101: 00 (72) Inventor Yoji Ishikawa Shimoseito, Kiyose City, Tokyo 4-chome 640 Obayashi Corporation Technical Research Institute Co., Ltd. (72) Inventor Shigeyoshi Osawa 949 Uemiya, Shigemachi, Innoshima-shi, Hiroshima F-term in Greentech Co., Ltd. (Reference) 4B065 AA01X AA57X AC14 BB04 BB22 CA28 CA56 4D004 AA41 AB02 AB05 CA19 CC02 CC03 CC15 4H026 AA08 AA15 AA16 AA18 AB04

Claims (2)

[Claims] An oil-contaminated soil containing polycyclic aromatic hydrocarbons such as phenanthrene, anthracene, fluoranthene, pyrene, and chrysene is mixed with manure such as cow manure, human manure, sewage sludge compost, and beer cake compost. A method for decomposing and removing oil-contaminated soil by microorganisms, comprising microbial decomposing the polycyclic aromatic hydrocarbon. 2. An additive for oil decomposition comprising a compost such as cow dung compost, human dung compost, sewage sludge compost, and beer refuse compost as a main component.