JP2001078755A - Decomposition of naphthalene and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove naphthalene from the air or drainage including naphthalene. SOLUTION: A microorganism in Stenotrophomonas is allowed to grow in the decomposition tank 1 and a single element substance of naphthalene or a bad smelling air including naphthalene are introduced via the introduction pipe 2 into the decomposition tank in which the naphthalene in the bad-smelling air is effectively decomposed with the microorganism whereby the smell of naphthalene is removed from the bad-smelling air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a naphthalene decomposition method and a naphthalene decomposition method for effectively decomposing and removing naphthalene from odors and aqueous solutions containing naphthalene.

[0002]

2. Description of the Related Art Naphthalene may be contained in odors and wastewater generated in foundries, chemical factories, pharmaceutical factories, and the like. There is a need for a method of removing it. 2. Description of the Related Art Conventionally, there are various methods for removing certain components contained in odors and wastewater, for example, a method using a filter and a method utilizing the action of decomposing microorganisms. However, it is difficult to efficiently collect naphthalene and remove it from odors and the like by a conventional method using a filter, which is not practically sufficient. In addition, in the method using the decomposing action of microorganisms, it is possible to decompose and remove ammonia and hydrogen sulfide contained in odor and wastewater to some extent, but if naphthalene is contained in odor etc., this naphthalene can be effectively used. Is difficult to disassemble
Naphthalene removal efficiency is not sufficient.

[0003] The present invention has been made in view of the above circumstances, and has as its object to effectively decompose naphthalene contained in odor and wastewater by using a microorganism that can grow using naphthalene as a carbon source.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the first invention of the method for decomposing naphthalene of the present invention is as follows.
Sten for naphthalene alone or substances containing naphthalene
The naphthalene is decomposed by using a bacterium of the genus otrophomonas (stenotrophomonas).

In a second aspect of the present invention, there is provided a method for decomposing naphthalene according to the first aspect, wherein the substance containing naphthalene is an odor or an aqueous solution.

The method for decomposing naphthalene according to the third invention is the method according to the first or second invention, wherein a bacterium belonging to the genus Stenotrophomonas and a genus belonging to the genus Pseudomonas (Pseudomonas) or the genus Comamonas (Comamonas) are used.
It is characterized by decomposing naphthalene by using more than one kind of bacteria.

Further, the naphthalene decomposing apparatus of the present invention
It has a decomposition tank in which bacteria of at least Stenotrophomonas genus (Stenotrophomonas) grow, and the decomposition tank is configured so that naphthalene alone or a substance containing naphthalene is introduced into the tank, It is characterized in that the growth environment is adjusted to pH 5.8 to 8.5, preferably 6.5 to 7.5.

The present invention is directed to naphthalene alone or a substance containing naphthalene as described above. A typical example of the substance containing naphthalene is an aqueous solution such as odor and wastewater. However, the present invention is not limited to this, and can be widely applied to a substance containing naphthalene and wishing to decompose and remove this naphthalene. The substance containing naphthalene may contain other odor components and aqueous solution-soluble components, and is not limited to those containing only naphthalene. Further, the concentration of naphthalene in the substance containing naphthalene is not limited.

For the above decomposition object, Stenotrophom
Use bacteria of the genus onas (Stenotrophomonas). The bacterium uses naphthalene as a nutrient, that is, a carbon source, and degrades naphthalene by its physiological activity. The bacterium is usually available in nature and can be grown by culture. In addition, at least the Stenotrophomonas genus (Stenotrophomonas)
Is required, but may contain other bacteria. For example, in addition to bacteria of the genus Stenotrophomonas, one or more bacteria of the genus Pseudomonas (Pseudomonas) or the genus Comamonas (Comamonas) can be used. By mixing these bacteria, there is an advantage that these bacteria coexist when decomposing naphthalene, and more stable treatment can be performed.

The above-mentioned substance to be decomposed is usually introduced into a decomposition tank in which at least the above-mentioned bacteria of the genus Stenotrophomonas are growing and brought into contact with microorganisms. In the decomposition tank, as described above, Stenotroph
In addition to bacteria of the genus omonas (Stenotrophomonas), other bacteria, for example, one or more species of the genus Pseudomonas (Pseudomonas) or the genus Comamonas (Comamonas), can be grown, and the genus Stenotrophomonas ( Bacteria other than Stenotrophomonas) may be separated and grown in another decomposition tank to degrade substances other than naphthalene.

In the case of a large-scale apparatus, a cracking tank can be dug in the ground and this hole can be used as a cracking tank.
Also, an appropriate container can be used as a decomposition tank.
A plurality of decomposition tanks may be connected in series or in parallel, and the decomposition target may be different in each decomposition tank. In the decomposition tank, the microorganisms are usually grown by being activated on a microorganism carrier contained in the tank. As this microorganism carrier, generally used zeolites,
Inorganic materials and organic materials such as charcoal, slag, ceramics, activated carbon, and PVA gel can be used. Activating the bacteria on the carrier can be carried out by adding bacteria previously cultured elsewhere to the carrier.

In the above-mentioned tank, an environment suitable for the growth of the above-mentioned bacteria is desirable. From this viewpoint, the pH in the tank is adjusted to 5.8 to 5.8.
It is desirable to adjust to 8.5, and further, to 6.5 to 7.
Adjustment to 5 is more desirable. The pH is adjusted by, for example, adjusting the amount or concentration of the odor or the aqueous solution introduced into the decomposition tank, that is, adjusting the treatment amount to be decomposed, or adjusting the amount of water sprayed when water is sprinkled into the decomposition tank. It can also be carried out by adding a pH adjuster to the decomposition tank. In the decomposition tank having the pH adjusting function, growth of bacteria, that is, decomposition of naphthalene, can be performed under appropriate conditions. In the present invention, in order to maintain the environment of the decomposition tank in a good condition, in addition to the above-mentioned pH, the water content can be adjusted by watering, and the water sprinkled can be collected and used again for watering. The method of watering and the method of recovery at this time are not particularly limited.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. The deodorizing apparatus has a decomposition tank 1 having a box shape, a water-permeable shelf 1a below the decomposition tank 1, and an odor introduction pipe 2 connected to a ceiling. The odor introduction pipe 2 is connected to an odor source and a blower (not shown). Also, in the decomposition tank 1, the shelf 1
The microorganism carrier 3 is accommodated so as to be supported by a, and the lower part of the shelf 1a of the decomposition tank 1 is allocated to a water recovery unit 1b.

Further, an exhaust duct 4 is provided below the shelf 1a of the decomposition tank 1 and extends to the side, and the exhaust duct 4 is connected to an exhaust location (not shown). One end of a water recovery pipe 5 arranged outside the decomposition tank 1 is connected to the water recovery section 1b.
Is connected to a water storage tank 6 arranged near the decomposition tank 1. In the lower part inside the water storage tank 6,
The tip end of a water pump 7 whose one end is connected to the suction side of the watering pump 8 on the outside is arranged, and a watering device 9 is connected to the discharge side of the watering pump 8. In addition, decomposition tank 1
Is provided with a pH measuring device 10.

Next, the operation of the deodorizing device will be described. At the beginning of the operation, a culture solution (not shown) containing bacteria of the genus Stenotrophomonas is added to the decomposition tank 1 in advance. Then, an odor containing naphthalene is introduced into the decomposition tank 1 through the odor introduction pipe 2,
By operating the pump 8, the water for watering in the water storage tank 6 is pumped by the water pump 7, water is sprinkled toward the carrier 3 by the water spraying device 9, and deodorizing treatment is performed. A part of the water spray passes between the carriers 3, moves from the shelf 1 a to the water receiver 1 b, and circulates by flowing back to the water storage tank 6 through the water recovery pipe 5. By the above operation, the naphthalene component in the odor is decomposed in the decomposition tank 1 by the bacteria, and the processing gas from which the naphthalene is decomposed and removed is sent from the exhaust duct 4 to the outside of the decomposition tank 1.

On the other hand, in a pH measuring device, p
H is measured, and the growth environment is adjusted by adjusting the pH of the circulating water so that the pH falls within a predetermined range. That is, if the pH is higher than the expected range, an acid is added, and if the pH is lower than the expected range,
The pH in the decomposition tank 1, that is, the pH of the growth environment of the bacteria is adjusted by adding an alkali to neutralize the solution. Thereby, the activity of the bacterium becomes active, and naphthalene is effectively decomposed and removed.

[0017]

EXAMPLES To the carrier 3 of the decomposition tank 1 shown in the above embodiment, Stenotrophomonas genus (Stenotrophomonas) cultured in advance was added. For comparison, a comparative decomposition tank to which activated sludge was added was separately prepared. An odor containing naphthalene was passed through each of the decomposition tanks to perform a deodorization treatment. At this time, the odor gas component concentration and the odor concentration at the entrance and the exit were measured and are shown in the table. At this time, the pH of the decomposition tank was 7.2 in the example and 7.2 in the comparative decomposition tank. As is clear from the above table, Stenotro
In the method using the decomposition tank to which bacteria of the genus phomonas were added (the method of the present invention), naphthalene was effectively removed, and the odor concentration was significantly reduced. On the other hand, in the method using the comparative decomposition tank to which the above-mentioned bacteria were not added (conventional method), naphthalene was hardly removed, and therefore, the decrease in odor concentration was small. Therefore, it was clarified that naphthalene was effectively removed only when a bacterium belonging to the genus Stenotrophomonas was used.

[0018]

[Table 1]

[0019]

As described above, according to the method for decomposing naphthalene of the present invention, naphthalene is decomposed by using a bacterium of the genus Stenotrophomonas against a substance containing naphthalene or a substance containing naphthalene. Therefore, when naphthalene is effectively decomposed and odors and drainage are targeted, naphthalene is reliably removed.

Further, according to the naphthalene decomposing apparatus of the present invention, there is provided a decomposing tank in which at least bacteria of the genus Stenotrophomonas grows, and the decomposing tank contains naphthalene alone or a substance containing naphthalene in the tank. And the growth environment of the above bacteria is adjusted to pH
Adjusting to 5.8 to 8.5, preferably 6.5 to 7.5, allows the above bacteria to grow in an optimal environment, and thus reliably and effectively reduces naphthalene in the target introduced into the decomposition tank. Can be decomposed and removed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a deodorizing device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deodorizing tank 1b Water recovery part 2 Odor introduction pipe 3 Carrier 4 Exhaust duct 5 Water recovery pipe 6 Water storage tank 7 Pumping pipe 8 Pump 9 Water sprinkler 10 pH meter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C12N 1/00 ZAB (72) Inventor Kyuken Uenori 1-6-1, Funakoshiminami, Aki-ku, Hiroshima-shi, Hiroshima-ken No. Within Japan Steel Works, Ltd. (72) Inventor Maki Ogasawara 1-6-1, Funakoshi Minami, Aki-ku, Hiroshima-shi, Hiroshima F-term inside Japan Steel Works, Ltd. 4D040 DD01 DD11 DD31

Claims (4)

[Claims] 1. A method for decomposing naphthalene, which comprises decomposing naphthalene against a substance containing naphthalene alone or a substance containing naphthalene using a bacterium belonging to the genus Stenotrophomonas. 2. The method for decomposing naphthalene according to claim 1, wherein the substance containing naphthalene is an odor or an aqueous solution. 3. A method for decomposing naphthalene using a bacterium of the genus Stenotrophomonas and at least one bacterium of the genus Pseudomonas (Pseudomonas) or the genus Comamonas (Comamonas). The method for decomposing naphthalene according to claim 1 or 2. 4. It has a decomposition tank in which at least bacteria of the genus Stenotrophomonas (Stenotrophomonas) grow,
The decomposition tank is configured such that naphthalene alone or a substance containing naphthalene is introduced into the tank, and the growth environment of the bacteria is pH 5.8 to 8.5, preferably 6.5.
Naphthalene decomposer characterized by being adjusted to 7.5