JPH08141595A - Treatment of ammonia-containing water - Google Patents

Abstract

PURPOSE: To treat ammonia-containing water by accelerating the nitration action of nitrifying bacteria contained in the circulating water of a closed system. CONSTITUTION: In a method for treating ammonia-containing water using nitrifying bacteria, bacterial cells of heterotrophic bacteria having activity to nitrifying bacteria are added to accelerate the nitration reaction of nitrifying bacteria. By this method, the acclimatizing period of an ammonia-containing water treatment apparatus using nitrifying bacteria can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating ammonia-containing water by promoting the nitrification reaction of nitrifying bacteria contained in closed-system circulating water such as farming and transporting facilities for aquatic animals and aquariums, and treating wastewater, sewage and The present invention relates to a method that can be used as a method for promoting the nitrification reaction of nitric acid bacteria widely distributed in the natural world such as human waste treatment equipment, soil, seawater and river water.

[0002]

2. Description of the Related Art Nitrifying bacteria are autotrophic bacteria that oxidize ammonia or nitrite into nitrite or nitric acid, respectively, and synthesize bacterial cell components with carbon dioxide as the sole carbon source (all metabolites in cells are converted to carbon dioxide. It has been said that the nitrification reaction of nitrifying bacteria is inhibited by the coexistence of organic substances.

For nitrifying bacteria, ammonia-oxidizing bacteria that oxidize ammonia to nitrite (hereinafter referred to as "nitrite")
And a nitrite-oxidizing bacterium that oxidizes nitrite into nitrate (hereinafter referred to as "nitrate bacterium"). The respective chemical reaction formulas are as follows.

Embedded image (a) Ammonia oxidation reaction of nitrite bacteria NH ₄ ⁺ + 3 / 2O ₂ → NO ₂ ⁻ + H ₂ O + 39.5k
cal (b) Nitrite oxidation reaction of nitric acid bacteria NO ₂ ⁻ + 1 / 2O ₂ → NO ₃ ⁻ +21.6 kcal

In order to utilize nitrifying bacteria for purification of waste water, etc., it is first necessary to secure a sufficient amount of bacteria to exert their nitrifying performance. Farming and transport equipment for aquatic animals,
In the case of closed system circulating water such as an aquarium, wastewater, sewage, and night soil treatment, nitrifying bacteria are present in the water even though they are present in a small amount, and ammonia (NH ₄ ⁺ ) and phosphorus (PO ₄ ^3- ) And oxygen (O ₂ ), and if kept at an appropriate water temperature, the nitrifying bacteria naturally grow and the nitrification reaction appears. However, according to this method, it takes a long time until the nitrification performance is sufficiently exhibited (this period is referred to as "acclimation period"). In order to shorten the acclimatization period of the nitrification device (that is, the nitrification bacterium), there is a method of transplanting the nitrification bacterium as an inoculum from another nitrification device that exhibits sufficient nitrification performance. In this case, the acclimatization period can be shortened slightly, but it usually takes several months.

Further, in order to improve the performance of the nitrification apparatus for ammonia-containing water, it is necessary to keep the bacterial cells in the apparatus at a high concentration. For that purpose, the nitrifying bacteria in a floating state as in the conventional activated sludge method are used. There is a method of attaching nitrifying bacteria to a carrier instead of the method of using. As the adhesion carrier, sand, activated carbon,
Porous ceramics, plate-shaped or granular plastic moldings, etc. are used. The larger the specific surface area (the value obtained by dividing the surface area of a simple substance by its volume), the larger the amount of adhered bacteria, and the higher the bacterial cell concentration in the device can be maintained.

[0006]

The method of treating ammonia-containing water using such nitrifying bacteria has the following problems. (1) The acclimatization period of the ammonia-containing water nitrification device is extremely longer than that of the organic wastewater purification device. The cause is that the growth of nitrifying bacteria used in ammonia-containing water nitrification equipment is higher than that of heterotrophic bacteria used in organic matter-containing wastewater purification equipment (bacteria that depend on organic compounds that take in carbon sources from outside the body). Because it is late.

(2) In order to shorten the acclimatization period of the nitrification apparatus, an amount of nitrifying bacteria sufficient to sufficiently exert the nitrification performance may be prepared in advance and put into the apparatus at startup. By the way, in the case of conventional nitrification equipment such as wastewater, we tried to shorten the acclimatization period by putting activated sludge in a separate facility, which already has sufficient nitrification performance, into the equipment at startup. However, it took a considerable period of time before the nitrification performance was exhibited regardless of the floating state or the adhered state.

(3) Even after the acclimatization of the nitrification apparatus is completed and the normal operation is started, nitrifying bacteria may be damaged by some cause in the system and the nitrification performance may be deteriorated. Especially, nitrifying bacteria in a floating state may flow out together with the treated water and the concentration in the apparatus may be significantly reduced. There is no such decrease in the adherent nitrifying bacteria, and there is an advantage that nitrifying bacteria can be kept at a high concentration in the device. However, even in that case, the time required for performance recovery is longer than that for an organic wastewater purification device, and it is necessary to shorten the time required for performance recovery.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a method for treating ammonia-containing water capable of shortening the acclimatization period in a treatment apparatus for ammonia-containing water using nitrifying bacteria.

[0010]

Means for Solving the Problems As a result of intensive research to solve the above-mentioned problems, the present inventors have found that even in the case of heterotrophic bacterial cells which were conventionally considered to inhibit the growth of nitrifying bacteria. The inventors have discovered that there are some that promote the nitrification reaction of nitrifying bacteria, especially nitrite bacteria, and have completed the present invention. That is, the present invention is characterized in that (1) in a method of treating ammonia-containing water with nitric acid bacteria, the cells of a heterotrophic bacterium having activity in nitrifying bacteria are added to promote the nitrifying reaction of nitrifying bacteria. Ammonia-containing water treatment method,
(2) The method for treating ammonia-containing water according to the above (1), characterized in that nitrifying bacteria in the form of being attached to and carried by a carrier are used as the nitrifying bacteria.

[0011]

According to the method of the present invention, the nitrifying ability of nitrifying bacteria, particularly nitrite bacteria, is promoted by the active cells of heterotrophic bacteria,
Ammonium ion (NH ₄ ⁺ ) within a relatively short time
Are oxidized to nitrate ions. The heterotrophic bacterium used in the method of the present invention is particularly active among nitrifying bacteria (promotes the growth of nitrifying bacteria and promotes nitrification reaction) among the heterotrophic bacteria. Examples of such heterotrophic bacteria having activity on nitrifying bacteria include Gram-positive fungi such as Bacillus and Streptococcus, and Gram-negative fungi such as Escherichia coli, Vibrio, and Pseudomonas. As a method of adding the viable cells of the heterotrophic bacterium to the ammonia-containing hydronitrification device using nitrifying bacteria, a culture solution of separately cultivated heterotrophic bacteria may be added as it is, but by a method such as centrifugation. It is preferable to use the concentrated and separated bacterial cells because they are easy to handle, such as in transportation, and the addition amount can be easily controlled.

When the nitrifying bacterium is used by adhering it to a carrier such as sand, activated carbon, porous ceramics, a plate-shaped or granular plastic molded product, and supporting it, the concentration of the nitrifying bacterium can be easily maintained and adjusted. Become. In this case, not only nitrifying bacteria but also both nitrifying bacteria and heterotrophic bacterial cells having activity on these nitrifying bacteria may be attached to the carrier. In addition, while only nitrifying bacteria are attached and carried, while circulating contact with the treated water containing the heterotrophic bacterial cells,
Depending on the conditions, the cells of the heterotrophic bacteria also become adhered and carried, and this state can be used in other devices. Porous ceramics having a large specific surface area are particularly preferable as the carrier used here. The mechanism by which the active cells of the heterotrophic bacteria promote nitrifying ability of nitrifying bacteria is still unknown.

[0013]

[Examples] The effects of the present invention will be demonstrated with reference to specific examples of the present invention. In this example, as representative strains of nitrifying bacteria, nitrite was Nitrosomonas europaea ATCC25978, and nitrobacter was Nitrobacter agilis ATCC1412.
3) was used. In addition, here, the culture of nitric acid bacteria was carried out under high pressure sterilized medium (Lewis, RF and D. Pramer, 1958.
"Isolation of Nitrosomonas in pure culture", 76,52
4-528) and aseptically operated. In this example, the nitrous acid concentration was measured by the Grease-Lomiin reagent, and the ammonia concentration was measured by the phenol blue method.

[0014]

[Table 1]

(Example 1) LB (Lur placed in a test tube
ia-Bertani) medium (composition is shown in Table 2) 10
Bacillus subtilis IFO 3513, which is a representative species of Gram-positive heterotrophic bacteria (hereinafter referred to as "Gram-positive bacteria")
8 ml of the LB medium placed in a Sakaguchi flask was inoculated with 8 ml of the liquid that had been inoculated and pre-cultured by shaking at 30 ° C. for 24 hours, and shake-cultured at 30 ° C. for 24 hours to enrich the cells. This culture solution is centrifuged (9000 x
G, 10 minutes, 4 ° C.) to collect the cells, and the cells were washed with sterile pure water to remove the medium components to obtain active cells.

[0016]

[Table 2]

Next, a concentrated solution of nitrite bacteria, which has been separately cultured in advance,
In addition, the nitrite concentration is 6.8 x 10 ⁶cells / mm
Fresh medium adjusted to liter (see Table 1 above)
Erlenmeyer flask (200 ml)
Tol) and 0.5 mg- of the above-mentioned active cells
Add to dry matter / ml and add at 30 ℃
Rotation culture was carried out for 120 hours. Start culture for this culture
The nitrite concentration at the time and at the end was measured. In addition, this
Nitrite in the example is the ammonia in the medium used.
(A) The component is generated by being oxidized by the nitrite.
For comparison, the above-mentioned active cells were added in parallel with this.
Nitrite-only culture (control) and Nitrite
For the culture solution containing only Bacillus subtilis that does not contain acid bacteria
A nitrification test was conducted. The above results are shown in Table 3.

[0018]

[Table 3]

Further, the same amount of the above-mentioned active cells of Bacillus subtilis
Streptococcus, a typical Gram-positive bacterium of
Activity of Echalis (Streptococcus faecalis IFO 12580)
The results of conducting the same nitrification test as above with the addition of bacterial cells were
Nitrite concentration (NO ₂-N) is 395 μg / mi
It was a lilt. From this, only Bacillus subtilis produces nitrite
It does not have the ability to grow, but by adding active Gram-positive bacteria,
It can be seen that the nitrification reaction of nitric acid bacteria is promoted.

(Example 2) Escherichia coli (Eshericha coli IFO 3301) which is a representative strain of Gram-negative heterotrophic bacteria (hereinafter referred to as "Gram-negative bacteria")
Active cells were prepared in the same manner as in Example 1, and 0.5
A nitrification test was performed under the same conditions as in Example 1 with respect to the culture solution added so as to have mg-dry matter / milliliter. Further, in parallel, a test was conducted in which only Gram-negative bacteria were added. The results are shown in Table 4.

[0021]

[Table 4]

Further, in place of the active bacterial cells of Escherichia coli, a representative gram-negative bacterial cell, Vibrio anguiralum (Vibr.
io anguillarum IFO 12710) or Pseudomonas fluorescens IAM 12001 were used in the same amount, but the nitrite concentration (NO ₂ -N) at the end of the culture was 397 and 345 μg / ml, respectively. . From this, it can be seen that although E. coli alone has no ability to produce nitrite, the addition of active Gram-negative bacterial cells promotes the nitrification reaction of nitrite.

(Example 3) 200 ml of a mixture of activated sludge in a small-scale sewage treatment plant containing various microorganisms was collected by centrifugation (900 rpm, 10 min) and suspended in 200 ml of the medium shown in Table 1 above. Volatile solids concentration (MLVSS) of the activated sludge mixture used is 1,790 p
pm. Since nitrite and nitrate ions were not detected in the supernatant of the activated sludge, the nitrifying activity of nitrite bacteria and nitrate bacteria in the activated sludge was extremely weak.

Next, the above suspension was treated with the Bacillus subtilis cells of Example 1.
Is 0.5 mg / milliliter of the E. coli cells of Example 2.
And nitrite (Nitrosomonas euro)
Pae: Nitrosomonas europaea ATCC25978) and nitric acid bacteria
(Nitrobacter agilis AT
CC14123) 3.0 × 10 each⁸, 5.0 × 10 ⁷
Add temperature so that the concentration is cclls / ml
Aeration batch for 72 hours under the conditions of 30 ° C and aeration of 1VVM
The test was conducted. This aeration mixture is a membrane filter.
Ammonia concentration in liquid filtered with (pore size 0.45 μm)
(NH_Four ⁺-N) was measured. The results are shown in Table 5.
The nitrite concentration after 72 hours of culture of each aeration mixture
Degree (NO₂-N) progressed nitrification reaction, and both were 1 μg /
It was less than a milliliter. More gram positive or
Activated sludge is mixed by adding negative bacterial cells
However, the nitrification reaction of nitrites and nitrates is promoted
The residual ammonia concentration decreases and the nitrite concentration also increases.
You can see that not.

[0025]

[Table 5]

(Example 4) Particle size 5 mm, specific surface area 100
A column filled with 200 ml of 0 m ² / m ³ of porous ceramics was filled with 2.5 × 10 ⁷ cells of nitrite.
ls / ml, nitric acid bacterium concentration is 9.7 × 10 ⁷ ce
The nitrifying bacteria were adhered to and supported on the ceramics by adding 200 ml of the lls / ml nitrifying bacteria solution. 1 liter of a fresh medium of Table 1 containing 0.5 mg-dry matter / milliliter of Bacillus subtilis active cells obtained in the same manner as in Example 1 was dissolved in oxygen at a liquid temperature of 30 ° C. and a linear flow rate. Circulation contact was performed at 3 m / h for 120 hours. The ammonia concentration of this culture solution was measured at the start and end of the culture. For comparison, a nitrification test was also conducted on a fresh medium (control) containing no active cells in parallel with this. Table 6 shows the results.

[0027]

[Table 6]

Further, the same nitrification test as described above was carried out by adding the same amount of the active bacterium of Streptococcus faecalis IFO 12580, which is a typical Gram-positive bacterium, in place of the active bacterium of Bacillus subtilis. As a result, the ammonia concentration (NH ₄ ⁺ -N) at the end of the culture was 115 μg.
/ Ml. From these results, the nitrification reaction of nitrifying bacteria was promoted by the addition of active Gram-positive bacteria,
It can be seen that the ammonia concentration decreases quickly.

(Example 5) Escherichia coli (Eshericha coli IFO 3301), which is a representative bacterial species of Gram-negative heterotrophic bacteria (hereinafter referred to as "Gram-negative bacteria")
The same filling material as in Example 4 was used using the liquid prepared by adjusting the active cells in the same manner as in Example 2 to the medium of Table 1 to which 0.5 mg-dry matter / ml was added. A nitrification test was carried out under the same conditions as in Example 4, using the nitrifying bacteria adhered and supported on The results are shown in Table 7. In addition, instead of the active cells of Escherichia coli, a typical Gram-negative bacterium, Vibrio anguillarum IFO 1
2710) or Pseudomonas fluorescens (Pseudomo
nas fluorescens IAM 12001) using the same amount of active cells, ammonia concentration (NH ₄ ⁺ -N) at the end of culture was tested.
Were 113 and 165 μg / ml, respectively. From this, it can be seen that the addition of active Gram-negative bacterial cells promotes the nitrification reaction of nitrifying bacteria and the ammonia concentration decreases rapidly.

[0030]

[Table 7]

(Example 6) 200 ml of the activated sludge mixed solution of a small-scale sewage treatment plant containing various microorganisms was collected by centrifugation (900 rpm, 10 min) so that the concentration of volatile solids (MLVSS) was 500 ppm. In addition to 1 liter of the fresh medium shown in Table 1 above, the same nitrifying bacteria as those used in Example 4 were adhered to and carried by the same filler as in Example 4 to obtain Example 4.
A nitrification test was conducted under the same conditions as above. Since nitrite and nitrate ions were not detected in the supernatant of the activated sludge, the nitrifying activity of the nitrite and nitrate of the activated sludge was extremely weak. In addition, 0.5 mg-
Dry matter / ml of Bacillus subtilis active cells (obtained in Example 1) or E. coli active cells (obtained in Example 2) were added. Further, a nitrification test was similarly conducted on a medium to which only activated sludge was added. The results are shown in Table 8. From this, it was found that the ammonia concentration was decreased and the nitrification reaction of nitrite bacteria and nitric acid bacteria was promoted even when only activated sludge was added. Further, it was found that the nitrification reaction was further promoted by mixing with activated sludge and a single bacterial species such as Bacillus subtilis or Escherichia coli.

[0032]

[Table 8]

[0033]

【The invention's effect】

(1) When the cells of heterotrophic bacteria having activity on nitrifying bacteria are added as in the present invention, the nitrifying capacity (nitric acid forming capacity) is more than doubled as compared with the case of the liquid containing only nitrifying bacteria. To do. Therefore, according to the present invention, it is possible to reduce the capacity of the ammonia-containing water treatment device to half that of the conventional one.
This effect is the same even when nitrifying bacteria attached to the carrier are used. (2) According to the present invention, a single bacterial species having activity against nitrifying bacteria such as Bacillus subtilis or Escherichia coli in an ammonia-containing water treatment device utilizing nitrifying bacteria even when various microorganisms such as activated sludge are mixed. The addition of N.sub.2 promotes the nitrification reaction and improves the ammonia-containing water treatment capacity. (3) The nitrification device has a low nitrification capacity (ammonia treatment capacity) at the time of startup or when trouble occurs. Even in such a case, the nitrification capacity (ammonia treatment capacity) can be rapidly improved or recovered by the effect of the above item (1) as compared with the conventional one. (4) By adhering nitrifying bacteria such as nitrite bacteria and nitric acid bacteria to the carrier, handling becomes easy, and these fungi are washed away from the nitrification device (ammonia-containing water treatment device),
There is no fear that the concentration will change. (5) Bacteria of Gram-positive or Gram-negative bacteria such as Bacillus subtilis or Escherichia coli are usually economically and easily obtained from fermentation effluent. This makes it possible to effectively use the fermentation effluent that was originally discarded.

Claims (2)

[Claims] 1. A method for treating ammonia-containing water using nitrifying bacteria, wherein the cells of a heterotrophic bacterium having activity in nitrifying bacteria are added to promote the nitrifying reaction of nitrifying bacteria. Method for treating contained water. 2. The method for treating ammonia-containing water according to claim 1, wherein nitrifying bacteria in the form of being attached to and supported by a carrier are used as the nitrifying bacteria.