JP6161210B2 - Method and apparatus for low temperature treatment of ammonia nitrogen containing water - Google Patents

Description

  The present invention relates to a method and apparatus for treating ammonia nitrogen-containing water that biologically nitrifies ammoniacal nitrogen at low temperatures, and in particular, environmental purification such as sewage treatment, industrial waste liquid treatment, lake purification, Regarding removal of ammonia in water at water purification plants and aquariums.

  In food factories and chemical factories, waste liquids containing low to high ammonia concentrations are discharged. Since these waste liquids cause eutrophication of water bodies and a decrease in dissolved oxygen, it is necessary to treat them before discharging them from factories.

  In general, biological treatment is often performed in medium to high concentration ammonia treatment. When biologically treating ammonia nitrogen in wastewater, a treatment method using an activated sludge method is usually performed. In this method, ammonia is nitrified by nitrifying bacteria to form nitric acid or nitrous acid, and then converted to nitrogen gas by denitrifying bacteria to remove nitrogen contained in the wastewater.

  As nitrifying bacteria used in such an activated sludge method, the present inventors have so far identified a nitrifying group (AH group, detected by culturing for 8 weeks in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more. (Ammonia oxidizing bacteria detected by MPN method using High ammonium media) (MPN method: most probable number method), and nitrifying bacteria group detected by culturing for 8 weeks in a low concentration ammonia sulfate solution with a concentration of 100 mg / L ( The AL bacteria group (Ammonia oxidizing bacteria detected by MPN method using Low ammonium media) has been studied and disclosed (Patent Document 1 and Non-Patent Document 1). In this process, the AH fungus group is effective for treatment of high concentration ammoniacal nitrogen-containing water (about 400 mg / L to 500 mg / L), and the AL fungus group is low concentration ammoniacal nitrogen-containing water (about 100 mg). / L or less) was found to be effective for the treatment. Since the concentration of ammoniacal nitrogen in general household wastewater is as low as 20 to 40 mg / L, the AL fungus group suitable for the treatment of low-concentration ammoniacal nitrogen-containing water is mainly used for the treatment of such wastewater. It is used for.

Japanese Patent No. 325287

Tatsuo Tsuno and Hiroyoshi Emori, “Advanced treatment technology using entrapped immobilization microorganism carrier”, water and wastewater, 1997, vol. 39, no. 8, p. 24-29

  Usually, domestic wastewater is transported to a wastewater treatment plant through underground sewage pipes, so the temperature is less likely to drop compared to the outside air even in winter. Moreover, since the wastewater treatment tank is often heat-insulated such as a cover, the temperature of the wastewater does not change greatly throughout the year, and it is rarely below 15 ° C even in winter, and below 10 ° C. Very rare. However, in cold regions, the temperature of the wastewater may be below 15 ° C and below 10 ° C in winter. In such a case, it has been found that the treatment capacity may be significantly reduced in the wastewater treatment using the AL fungus group. This is considered to be caused by the fact that the ammonia nitrification activity of the AL fungus group decreases at 15 ° C. or less, and that the activity significantly decreases when the temperature falls below 10 ° C. At 10 ° C. or less, it was found that nitrification hardly progressed even if the bacteria were kept at a high concentration, and nitrification hardly proceeded. Therefore, there is a need for a method and apparatus that can stably treat ammonia-containing nitrogen-containing water even when the water temperature is 15 ° C. or lower.

  The present invention addresses such problems, and generally treats wastewater at a low temperature using the AH fungal group used for treating high-concentration ammoniacal nitrogen-containing water. This is because the AH bacteria group obtained by the present inventors as a result of earnest research can be stably treated with ammoniacal nitrogen-containing water without significantly reducing the treatment activity even at low temperatures. Based on the findings of

  Accordingly, an object of the present invention is to provide a method capable of stably treating ammonia nitrogen-containing water even at a low temperature of 15 ° C. or lower.

  Another object of the present invention is to provide an apparatus capable of stably treating ammonia nitrogen-containing water even at a low temperature of 15 ° C. or lower.

  Yet another object of the present invention is to provide a carrier holding AH bacteria that can stably treat ammoniacal nitrogen-containing water even at a low temperature of 15 ° C. or lower.

A method of treating ammonia nitrogen-containing water according to an aspect of the present invention includes:
Ammonia nitrogen-containing water having an ammonia nitrogen concentration of 1 to 300 mg / L and a carrier on which a nitrifying bacteria group preferentially propagated by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks A nitrification step of nitrifying ammonia in the ammoniacal nitrogen-containing water by contacting at 0 ° C. or higher and 15 ° C. or lower in an aerobic atmosphere;
including.

Moreover, the method of treating ammonia nitrogen-containing water according to another aspect of the present invention includes:
Nitrifying bacteria detected by contacting ammonia-containing nitrogen water having an ammonia nitrogen concentration of 100 to 1000 mg / L with a microorganism-supporting carrier and culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks. A culture process for preferentially culturing the group;
The cultured nitrifying bacteria group is brought into contact with the ammoniacal nitrogen-containing water having an ammoniacal nitrogen concentration of 1 to 300 mg / L in an aerobic atmosphere at 0 ° C. or higher and 15 ° C. or lower to bring the ammoniacal nitrogen-containing water into contact. A nitrification step of nitrifying ammonia.

Moreover, the treatment apparatus for ammoniacal nitrogen-containing water according to another aspect of the present invention,
A nitrification tank,
An introduction unit for introducing ammoniacal nitrogen-containing water having an ammoniacal nitrogen concentration of 1 to 300 mg / L into the nitrification tank;
A discharge section for discharging the ammoniacal nitrogen-containing water treated from the nitrification tank,
The nitrification tank contains a carrier on which a nitrifying bacteria group preferentially propagated by culturing for 8 weeks in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more,
In the nitrification tank, the ammoniacal nitrogen-containing water is treated at 0 ° C. or more and 15 ° C. or less.

Moreover, the treatment apparatus for ammoniacal nitrogen-containing water according to another aspect of the present invention,
A culture tank for culturing a group of nitrifying bacteria detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks;
A first introduction part for introducing ammonia nitrogen-containing water having an ammonia nitrogen concentration of 100 to 1000 mg / L into the culture tank;
A discharge section for discharging the nitrifying bacteria group cultured from the culture tank; and a nitrification tank connected to the discharge section;
A second introduction part for introducing ammonia nitrogen-containing water having an ammonia nitrogen concentration of 1 to 300 mg / L into the nitrification tank;
A discharge section for discharging the ammoniacal nitrogen-containing water treated from the nitrification tank,
Supplying the cultured nitrifying bacteria group from the culture tank to the nitrification tank via the discharge section;
In the nitrification tank, the ammoniacal nitrogen-containing water is treated at 0 ° C. or more and 15 ° C. or less.

Furthermore, the bacteria holding carrier for the treatment of ammoniacal nitrogen-containing water according to another aspect of the present invention,
A carrier;
A group of nitrifying bacteria preferentially propagated on the carrier, which is detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks,
It is a bacteria-retaining carrier for treating 1 to 300 mg / L of ammoniacal nitrogen-containing water at 0 to 15 ° C.

  According to the present invention, it is possible to provide a treatment method and apparatus for ammoniacal nitrogen-containing water that can perform stable ammonia treatment at a low water temperature of 15 ° C. or less, and obtain stable treated water that is always stable.

It is a schematic diagram of the nitrification tank by this invention. It is a figure which shows the apparatus for ammonia nitrogen containing water treatment by this invention provided with an AH fungal group culture tank. It is a figure which shows the apparatus for water treatment of ammonia nitrogen containing water by this invention to which two or more nitrification tanks were connected. It is a figure which shows the example of application of the multistage processing type by this invention. It is a figure which shows the example of application of the processing flow of the AH fungal group addition type by this invention. It is a figure which shows the influence of the water temperature which acts on the nitrification rate. It is a figure which shows the daily change of the process characteristic by this invention. It is a figure which shows the relationship between the load and nitrification speed by this invention. It is a figure which shows the daily change of the process characteristic by a conventional method. It is a figure which shows the relationship between the load by a conventional method, and nitrification speed.

  Hereinafter, embodiments of the present invention will be described in detail.

<Definition>
In the present specification, “AH fungal group” refers to a nitrifying bacterial group detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks, and “AL fungal group” This refers to a group of nitrifying bacteria detected by culturing in a low concentration ammonia sulfate solution having a concentration of 100 mg / L for 8 weeks. Therefore, any bacteria can be detected as long as it is detected under such conditions, and is not limited to a specific bacteria. As a specific example of the AH fungal group, it is considered that it belongs to the genus Nitrosomonas, but it is not determined taxonomically. A single bacterium from the AH fungal group can be isolated and used, but it is preferable from the viewpoint of stability of activity that a plurality of types of bacteria coexist as the AH fungal group.
In the present invention, “detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks” means at least 8 weeks in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more. This means that if cultured, nitrifying bacteria as AH bacteria are generated and can be detected, and it does not mean a culture period of just 8 weeks.
Moreover, although the upper limit concentration of the ammonium sulfate solution was not defined, the upper limit is the concentration limit at which nitrifying bacteria can be cultured.

  As used herein, “nitrification” refers to the production of nitric acid or nitrous acid from ammonia.

  In the present specification, the “microorganism holding carrier” refers to a carrier on which activated sludge or the like is fixed. The “microorganism holding carrier” also includes a entrapping immobilization microorganism carrier.

  In the present specification, “the carrier on which the nitrifying bacteria group preferentially propagated by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks” means the number of bacteria retained on the carrier. , Refers to a carrier having more AH bacteria than AL bacteria. The number of AH fungal groups is preferably 2 times or more of the number of AL fungal groups, more preferably 10 times or more, still more preferably 100 times or more, and most preferably 1000 times or more. . Further, in the present specification, “a carrier dominant in AH bacteria group” is also used synonymously.

  In the present specification, “medium to high concentration treatment nitrification tank” and “AH fungus group culture tank” are used synonymously. This is because the nitrification tank for medium to high concentration treatment functions as a tank for treating water containing medium to high concentration ammoniacal nitrogen, and at the same time, the AH fungal group is cultured in the tank.

<Activated sludge>
The AH fungal group used in the present invention can be acclimatized from general activated sludge, lake bottom mud and the like. Therefore, no special technique or raw material is required to obtain the AH bacteria group, and any method known in the art may be used.

  For example, the group of AH bacteria used in the present invention is a gellan gum medium (R. Takahashi, et al .: “Pure isolation of a new chemoautotrophic ammonia-oxidizing bacterium on gellan gum plate”, J. Fermentation and Bioengineering, vol. 74, No. 1, pp. 52-54 (1992)). Moreover, accumulation culture | cultivation is possible by fixing the activated sludge of a sewage treatment plant, and culture | cultivating with the inorganic wastewater which contains ammonia nitrogen concentration 100-1000 mg / L.

<Carrier>
In order to retain the bacterium on the carrier, methods such as (i) adhesion immobilization and (ii) entrapping immobilization can be used. In (i), a material having many irregularities such as a spherical or cylindrical carrier, a string-like material, a gel-like carrier, or a nonwoven material is preferable for bacterial adhesion, and the use of such a carrier improves the removal rate of ammonia nitrogen. To do. In (ii), a bacterium and an immobilization material (monomer, prepolymer) are mixed, polymerized, and the bacterium is comprehensively immobilized inside the gel. As the monomer material, acrylamide, methylenebisacrylamide, triacryl formal and the like are preferable. The prepolymer material is preferably polyethylene glycol diacrylate or polyethylene glycol methacrylate, and derivatives thereof can also be used. In terms of contact efficiency, inclusion shapes such as spherical, square, and cylindrical inclusion carriers, string inclusion carriers, and nonwoven inclusion inclusions with many irregularities are preferable, and the ammonia nitrogen removal rate is improved.

<Ammonia nitrogen-containing water>
The ammoniacal nitrogen-containing water to be treated according to the present invention includes, but is not limited to, wastewater such as domestic wastewater, human waste, and factory wastewater, and water in a domestic water tank and aquarium. Moreover, if ammonia nitrogen is contained, even the water can be treated by the method or apparatus according to the present invention.

  The ammoniacal nitrogen concentration of the ammoniacal nitrogen-containing water treated with the method and apparatus according to the present invention is preferably in the range of 1-1000 mg / L. Specifically, in the embodiment using the single tank type nitrification tank shown in FIG. 1, the ammoniacal nitrogen concentration is preferably in the range of 1 to 300 mg / L, and 1 to 100 mg / L in view of processing efficiency. Is more preferable. In the AH bacteria group culture tank shown in FIG. 2, it is preferably in the range of 100 to 1000 mg / L, and more preferably in the range of 200 to 500 mg / L from the viewpoint of processing efficiency. In the multistage treatment shown in FIG. 3, the range is preferably 50 to 500 mg / L, and more preferably 100 to 300 mg / L from the viewpoint of treatment efficiency.

  The temperature of the ammoniacal nitrogen-containing water to be treated by the method and apparatus according to the present invention is preferably 0 ° C. or higher and 15 ° C. or lower, and more preferably 0 ° C. or higher and 10 ° C. or lower in view of particularly excellent treatment activity than the conventional method. Further, it is more preferable to use at 0 ° C. or higher and 5 ° C. or lower in consideration of the further excellent treatment activity. That is, nitrification of ammonia nitrogen-containing water by the conventional method hardly progresses at 10 ° C. or lower, but according to the method and apparatus of the present invention, it is stable even at 10 ° C. or lower, further 5 ° C. or lower. Nitrification treatment can be performed. In addition, although the lower limit of the water temperature processed with a method and an apparatus is not set in particular, it understands that 0 degreeC vicinity which is a freezing point of water becomes a minimum, since this invention is related to water treatment.

  Specific embodiments of the method and apparatus according to the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

<Nitrification treatment>
A method and apparatus for nitrification of ammonia nitrogen-containing water according to the present invention will be described with reference to FIG. The nitrification tank 10 includes a carrier 12 in which AH bacteria are retained. By introducing ammonia nitrogen-containing water from the ammonia nitrogen-containing water introduction part 14, the ammonia nitrogen-containing water and the carrier come into contact with each other. The AH bacteria group retained on the carrier nitrifies ammonia to produce nitrous acid or nitric acid. The ammonia-containing nitrogen-containing water stays in the nitrification tank for a certain period of time and then flows out from the treated water outflow part 16 through the carrier separation network 18 as treated water. The treated water that has flowed out is then sent to a denitrification tank (not shown) where nitric acid and nitrous acid in the treated water are converted to nitrogen gas and removed.

Here, the nitrification tank may be anything as long as it can hold the carrier and waste water for a certain period of time, and the material and volume of the nitrification tank are not particularly limited. The filling rate of the carrier contained in the nitrification tank is preferably 1% to 60%, more preferably 5% to 20%, and most preferably 8% to 15% in terms of processing efficiency. Further, the time during which the ammonia nitrogen-containing water stays in the nitrification tank depends on the ammonia nitrogen content of the water to be treated, but is preferably approximately 0.3 to 24 hours, preferably 0.5 to 12 hours. It is more preferable that it is 1 to 3 hours, and it is most preferable in terms of processing efficiency. Depending on the NH ₄ —N load in the nitrification tank and the ammoniacal nitrogen content of the water to be treated, it is preferably about 0.01 to 1 kg-N / m ³ · d, preferably 0.1 to 0. more preferably from ^{5kg-N / m 3 · d} , in the range of 0.2~0.3kg-N / ^{m 3} · d is, the processing speed of the AH bacterial group is most preferable to increase.

  According to such a method and apparatus, wastewater treatment in a cold region and ammonia removal in a low temperature water tank such as an aquarium can be stably performed. In addition, ammonia can be effectively removed even when ammonia is mixed in clean water having a temperature lower than that of waste water. Moreover, even if it is other than a cold region, since the necessity to heat-treat a wastewater treatment facility reduces, a processing apparatus can be manufactured more compactly and at low cost. These advantages are also obtained in other embodiments of the invention described below.

<Operation for supplying AH bacteria group from AH bacteria culture tank>
In the sewage treatment plant, the effluent after sludge dehydration contains medium to high concentration ammonia. Therefore, FIG. 2 shows a flow equipped with an apparatus for culturing AH bacteria using this detachment solution. With such a configuration, the AH bacteria group cultured there can be supplied to the nitrification tank while treating the effluent containing medium to high concentration ammonia generated in a small amount at the sewage treatment plant. As a result, the treatment efficiency of wastewater containing low-concentration ammonia in the nitrification tank is increased, which is preferable. From the viewpoint of cost, it is preferable to use an unfamiliar carrier as the microorganism-retaining carrier used for culturing the AH bacteria group. In addition, since the AH bacteria group is sequentially supplied from the medium to high concentration treatment nitrification tank (culture tank) to the nitrification tank by adopting the configuration as shown in FIG. 2, the nitrification tank is a conventional activated sludge method, for example, floating A tank using a type activated sludge method may be used. The nitrification tank may contain a carrier holding the AH bacteria group. An embodiment including a carrier in which AH bacteria are held in a nitrification tank is preferable in that a larger amount of waste water can be treated at high speed and stably.

  Here, the configuration of FIG. 2 will be described in detail. The AH bacterium culture tank 20 contains a carrier 12 holding microorganisms, and waste water containing medium to high concentration ammoniacal nitrogen from the medium to high concentration ammonia nitrogen containing water introduction section 24 (100 to 100%). 1000 mg / L) is introduced and brought into contact with the carrier, and the AH bacteria group is preferentially cultured on the carrier. As the culture of the AH fungal group proceeds, a part of the proliferated AH fungal group leaks from the carrier and is supplied to the nitrification tank 100 through the AH fungal group discharge unit 22. Although depending on the configuration of the tank, the bacteria supplied to the nitrification tank stay on the nitrification tank on average several days to one month. In this nitrification tank 100, the supplied AH fungal group is contacted with the ammoniacal nitrogen-containing water introduced from the ammoniacal nitrogen-containing water introduction section 14 as in the case of FIG. This produces nitric acid. Next, similarly to the case of FIG. 1, the treated water flowing out from the treated water outflow part 16 is sent to a denitrification tank (not shown), and nitric acid and nitrous acid in the treated water are converted into nitrogen gas and removed. .

<Multistage processing>
The multistage treatment of ammoniacal nitrogen-containing water according to the present invention will be described with reference to FIG. This configuration is an example in which an environment that easily retains the AH bacteria group is prepared by configuring the medium concentration wastewater in a multi-stage treatment, and the treatment capability at a low water temperature is enhanced. Since a plurality of nitrification tanks are connected, wastewater containing higher concentration ammoniacal nitrogen can be treated at a time. In the figure, 28, 30, and 32 are the first nitrification tank, the second nitrification tank, and the third nitrification tank, respectively, and the concentration gradient in each tank can be made by multi-stage treatment, and the first nitrification tank has the highest NH ₄ -N. The concentration is high, and the concentration of NH ₄ -N decreases in the order of the second nitrification tank and the third nitrification tank. The growth of the AH fungal group depends on the NH ₄ -N concentration in the atmosphere, and the higher the concentration, the better the growth of the AH fungal group. Therefore, the AH fungal group easily grows in the first nitrification tank. And the AH bacteria group which proliferated in the 1st nitrification tank will be supplied to a 2nd nitrification tank or a 3rd nitrification tank. Thereby, the processing performance in the entire three-stage process is maintained even at a low temperature, and the temperature resistance is improved.

  The treatment procedure of the ammonia nitrogen-containing water is substantially the same as that in FIG. 1, and the medium-concentration ammonia nitrogen-containing water introduced into the first nitrification tank 28 from the medium-concentration ammonia nitrogen-containing water introduction unit 26 is In contact with the AH bacteria group held on the carrier 12 in one nitrification tank 28, the AH bacteria group held on the carrier nitrifies a part of the ammonia in the water to produce nitrous acid or nitric acid. The ammoniacal nitrogen-containing water is introduced into the second nitrification tank 30 after having stayed in the first nitrification tank 28 for a certain period of time. Here, as in the case of the first nitrification tank, the digestion of ammonia in water proceeds, and after staying for a certain time, the ammoniacal nitrogen-containing water flows out of the second nitrification tank 30 and moves to the third nitrification tank 32. The nitrification treatment is similarly performed here, and the treated water finally flowing out from the third nitrification tank is then sent to a denitrification tank (not shown) to convert nitric acid and nitrous acid in the treated water into nitrogen gas. Removed.

Each nitrification tank may have a different capacity, shape, and material, and the residence time and the filling amount of the carrier are different depending on the concentration and treatment amount of NH ₄ -N water containing ammonia nitrogen to be treated in each tank. May be. Moreover, the number of nitrification tanks can also be adjusted according to the property of the ammoniacal nitrogen-containing water to be treated.

<Application example of the present invention>
The flow of FIG. 4 and FIG. 5 is shown as an application example of this invention. FIG. 4 is equipped with a denitrification device according to the present method, and FIG. 5 is equipped with a device for introducing the AH fungal group preferred carrier of the present method into the nitrification tank of the modified circulation method or introducing the AH fungal group. is there.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited by an Example.

<Production of entrapped immobilization microorganism carrier>
Activated sludge from sewage treatment plant (obtained from T city end treatment plant, Gunma Prefecture), 15 parts of polyethylene glycol dimethacrylate ("Light Ester 14EG (product number)", manufactured by Kyoeisha Chemical Co., Ltd.), NNN'N 'tetramethylethylenediamine ("206-04006 (product number)", Wako Pure Chemical Industries, Ltd.) 0.5 part and water 69.25 parts are mixed to form a suspension, and potassium persulfate ("162-04235 (product number) ) ", Manufactured by Wako Pure Chemical Industries, Ltd.) When 0.25 part was added, the polymerization started and gelled. The obtained gel was cut into 3 mm square pellets and used in the following examples.

Example 1
<Production of AH bacteria dominant carrier>
The entrapping immobilization microorganism carrier cut into pellets was conditioned with inorganic synthetic waste water (NH ₄ -N: 400 mg / L) shown in Table 1 below. The acclimatization was performed in a nitrification tank having a volume of 1.4 L shown in FIG. 1 for 2 months with a load of 0.5 kg-N / m ³ · d. What was acclimatized for 2 months on the said conditions was used as a carrier of AH bacteria group predominance.

Comparative Example 1
<Preparation of carrier dominant in AL fungus group>
A load of 0.5 kg-N / m was used in the same manner as in the case of the carrier dominant in the AH fungus group except that the inorganic synthetic wastewater was diluted 10-fold with tap water (NH ₄ -N: 40 mg / L). It was prepared by acclimation at ³ · d and used as a carrier for the dominant AL fungus group.

<Measurement of the number of AH and AL bacteria>
(Preprocessing)
The following method was used to determine how much the AH fungal group and the AL fungal group were contained in the obtained carrier of the AH fungal group (Example 1) and the carrier of the AL fungal group (Comparative Example 1). Measured with.

First, as a pretreatment, the carrier was crushed and the bacteria were dispersed. A fixed amount of carrier was collected in 9 ml of sterilized water, and crushed and dispersed. A homogenizer (homogenizer PA type, manufactured by Ikemoto Rika Kogyo Co., Ltd.) was used for crushing, and an ultrasonic treatment device (US300 type, manufactured by Nippon Seiki Co., Ltd.) was used for dispersion. Table 2 shows pretreatment conditions.

(Measurement of the number of nitrifying bacteria)
After the pretreatment, the numbers of AH fungal group and AL fungal group were measured according to the most probable value method using a liquid in which bacteria were dispersed. First, a medium for counting the number of bacteria of the AH group and AL group shown in Table 3 was prepared, sterilized and filtered, and 9 mL each was placed in a plurality of test tubes that had been sterilized by dry heat using about 50 mg of CaCO _3. Noted. Next, a test tube different from that containing the measurement medium was prepared, 9 mL of sterilized water was added thereto, and further 1 mL of the pretreated liquid was added as a stock solution to dilute 10 times. 1 mL of this 10-fold diluted solution was extracted and added to another 9 mL of sterilized water to obtain a diluted solution diluted 100 times based on the stock solution. This operation was repeated to prepare a diluted solution diluted 10 to ¹⁰ times. Here, 1 mL of the diluted solution at each dilution rate was inoculated into 5 measuring media. Therefore, a total of 50 tubes were inoculated for one sample. The inoculated test tube was cultured with 2 to 3 non-inoculated test tubes at 30 ° C. for 8 weeks.

  After culture, drop 1 to 2 drops of Griess-Ilosvay reagent (preparation method: edited by Soil Microbial Society, “Soil Microbial Experiment Method”, Yokendo, p. 195, (Showa 50)). The presence or absence of nitrous acid accumulation was determined. Red or brown color development means accumulation of nitrite due to the growth of AH or AL fungal group. After a few minutes, add a small amount of zinc powder to the uncolored test tube and observe whether the red color is newly developed or not while the test tube is left still. Color development after the addition of zinc powder means that the nitrite once produced was oxidized to nitric acid by the nitrite-oxidizing bacteria. The number of test tubes that developed with and without zinc powder was recorded for each dilution step.

For the carrier dominant in AH bacteria group, in H medium, 5 from the third dilution water, 5 from the fourth dilution water, 4 from the fifth dilution water, 2 from the sixth dilution water, from the seventh dilution water Since it was 0, it was recorded as (5, 5, 4, 2, 0). From this value, P ₁ = 5, P ₂ = 4, P ₃ = 2, and after obtaining the most probable value from the most probable value table, multiply this by the dilution factor of P ₂ to calculate the number of viable bacteria per mL of stock solution did. In the L medium, there were 5 from the primary dilution water, 3 from the secondary dilution water, 2 from the tertiary dilution water, 0 from the quaternary dilution water, and 0 from the quintic dilution water. 2, 0, 0), and the number of viable bacteria per mL of the stock solution was calculated in the same manner.

The number of viable bacteria per 1 mL of the stock solution was calculated in the same manner for the carrier dominant in the AL group. The results are shown in Table 4.

From the above table, it can be seen that the carriers of Example 1 and Comparative Example 1 are carriers of the AH group dominant and AL groups dominant, respectively. The nitrification rate of each carrier was measured from the balance of water quality in continuous operation after acclimatization for 2 months with a load of 0.5 kg-N / m ³ · d in the nitrification tank with a capacity of 1.4 L shown in FIG. , 0.45 kg-N / m ³ · d and 0.46 kg-N / m ³ · d, respectively, which were almost equal. As the quality of raw water and treated _{water, NH 4 -N, NO 3 -N} , was measured _NO 2 -N. NH ₄ -N conforms to the indophenol blue colorimetric method (JIS-K0102, where JIS is an abbreviation for Japanese Industrial Standards), and NO ₃ -N and NO ₂ -N represent ion chromatograph analyzers (“ "ICS-1600 (product number)", manufactured by Dionex). In addition, since the suspended water in the treated water was slightly mixed, the treated water was filtered with a 0.45 μ filter (“DISMIC-25cs (product number)”, manufactured by Advantech Co., Ltd.) in advance.

<Measurement of nitrification rate at each temperature>
Example 2
Using the carrier prepared in Example 1 (AH bacteria group dominant carrier), the nitrification rate according to temperature was measured. For the evaluation, batch treatment was performed using a nitrification tank having a volume of 1.4 L shown in FIG. 1 to obtain a nitrification rate. The raw water used was NH ₄ —N ₄₀ mg / L obtained by diluting the inorganic synthetic waste water shown in Table 1 10 times. The carrier filling amount in the nitrification tank was 8%.

  Table 5 and FIG. 6 show the measurement results obtained by changing the temperature to 5, 10, 15 and 20 ° C. under the above conditions.

Comparative Example 2
The nitrification rate according to temperature was measured in the same manner as in Example 2 except that the carrier prepared in Comparative Example 1 (a carrier dominant in AL bacteria) was used. The results are shown in Table 5 and FIG. From this result, it can be seen that the carrier dominant in the AH group is more resistant to low temperature than the carrier dominant in the AL group. In particular, it can be seen that at a water temperature of 10 ° C. or less, the carrier predominantly AH group can obtain a significantly higher nitrification rate than the carrier predominantly AL group.

<Long-term low water temperature measurement>
Example 3
A long-term treatment operation was performed at 5 ° C. using the carrier prepared in Example 1 (AH group dominant carrier). In this treatment, synthetic inorganic wastewater (NH ₄ —N concentration: 48 to 66 mg / L) was used in the nitrification tank having the configuration shown in FIG.
The conditions of the processing operation are shown below.
Nitrification tank volume 1.4L
Residence time 6 to 12 hours Comprehensive carrier filling rate 8%
NH ₄ -N load 0.07 to 0.24 kg-N / m ³ · d
Operation period 100 days The results for Example 3 are shown in FIGS.

Comparative Example 3
A long-term treatment operation was carried out at 5 ° C. in the same manner as in Example 3 except that the carrier prepared in Comparative Example 1 (a carrier predominantly AL bacteria) was used. The results for Comparative Example 3 are shown in FIGS. It is clear that the AH bacteria-dominant carrier according to the present invention is excellent in treatment performance at low water temperature in both aging ability and nitrification rate against volumetric load.

<Operation for supplying AH bacteria group from AH bacteria culture tank>
Example 4
The apparatus of the flow of FIG. 2 was used. Medium-to-high concentration treatment of unfamiliar entrapped immobilization microorganism carrier (activated sludge immobilization carrier) produced using activated sludge using medium to high concentration ammoniacal nitrogen-containing water (desorbed liquid after sludge dehydration) The nitrification tank (cultivation tank) 20 is charged with a detachment liquid containing medium to high concentration ammonia, and the AH bacteria group is contained inside the carrier in the medium to high concentration nitrification tank (culture tank) 20. Was cultivated. A part of the AH bacteria group leaks from the carrier and is put into the nitrification tank 100. Activated sludge is suspended in the nitrification tank 100. Low concentration ammoniacal nitrogen-containing water was allowed to flow into the nitrification tank 100 from the ammoniacal nitrogen-containing water introduction section 14 to perform nitrification treatment.

Various water quality and equipment specifications are shown below.
Eluate 350~410mg / L after _NH 4 -N concentration <br/> sludge dewatering of various ammonium nitrogen-containing water
Waste water to be introduced into the ammoniacal nitrogen-containing water introduction section 32 to 40 mg / L
Specifications of nitrification tank 100 <br/> Nitrification tank volume 10L
Residence time 4 hours MLSS concentration 4,000 mg / L
NH ₄ -N load 0.25 to 0.32 kg-N / m ³ · d
Specification of nitrification tank (culture tank) 20 for medium to high concentration treatment Nitrification tank (culture tank) for medium to high concentration treatment 0.5 L
Residence time 12 hours Comprehensive carrier filling rate 20%
NH ₄ -N load 0.7 to 0.8 kg-N / m ³ · d

As the carrier used, the unfamiliar entrapped immobilization microorganism carrier (activated sludge immobilization carrier) described above was used. As the immobilized activated sludge, activated sludge from the T sewage treatment plant was used. The AH bacteria group grows on the carrier in the culture tank, the AH bacteria group leaks from the carrier, and is supplied to the nitrification tank, whereby nitrification is promoted at a low water temperature. When operated in winter with a small-scale apparatus according to the present invention, the water temperature was 10 to 13 ° C., and the ammoniacal nitrogen concentration in the treated water in the nitrification tank 100 was NH ₄ —N: 1 mg / L or less.

Comparative Example 4
In the same manner as in Example 4 except that a conventional method (floating activated sludge method) not equipped with a nitrification tank (culture tank) 20 for medium to high concentration treatment was used, NH ₄ -N 32 to ₄₀ mg / L was maintained at a residence time of 4 When treated with an MLSS concentration of 4000 mg / L for a time, a large amount of ammonia nitrogen remained in the treated water at a water temperature of 10 to 13 ° C., and the ammonia nitrogen concentration of the treated water discharged from the nitrification tank was NH ₄ -N: 9 -35 mg / L. Thus, the effects of the method and apparatus according to the present invention are obvious.

<Multistage processing>
Example 5
Processing was performed by the multistage processing shown in FIG.
The water quality and equipment specifications are shown below.
Waste water NH ₄ -N concentration 170-220 mg / L
Specifications of each nitrification tank 28, 30, 32 Volume of each tank 2L
Residence time of each tank 4 hours Comprehensive carrier filling rate 20%

The treatment was performed using the previously unfamiliar entrapped immobilization microorganism carrier (activated sludge immobilization carrier). As the immobilized activated sludge, activated sludge from the T sewage treatment plant was used. When operated in winter in the apparatus according to the present invention, the water temperature was 8 to 13 ° C., and the ammoniacal nitrogen concentration in the treated water was NH ₄ —N: 1 mg / L or less. Therefore, the effect of the method and apparatus according to the present invention is clear.

DESCRIPTION OF SYMBOLS 10 Nitrification tank 12 Support | carrier 14 Ammonia nitrogen containing water introduction part 16 Treated water outflow part 18 Carrier separation network 19 Nitrification liquid circulation line 20 Medium to high concentration treatment nitrification tank (AH fungus group culture tank)
22 AH group discharge part 24 Medium to high concentration ammonia nitrogen containing water introduction part 26 Medium concentration ammonia nitrogen containing water introduction part 28 First nitrification tank 30 Second nitrification tank 32 Third nitrification tank 100 Conventional nitrification tank 120 Conventional Carrier 130 conventional carrier 200 denitrification tank 310 denitrifying bacteria adhesion filler 500 organic substance supply tank

Claims (9)

A method for treating ammonia nitrogen-containing water,
A carrier in which ammonia-nitrogen containing water having an ammonia nitrogen concentration of 1 to 100 mg / L and a nitrifying bacteria group preferentially propagated by culturing for 8 weeks in a high-concentration ammonia sulfate solution having a concentration of 5000 mg / L or more; A nitrification step of nitrifying ammonia in the ammoniacal nitrogen-containing water by contacting at a temperature of 0 ° C. to 10 ° C. in an aerobic atmosphere,
Including methods. A method for treating ammonia nitrogen-containing water,
Nitrifying bacteria detected by contacting ammonia-containing nitrogen water having an ammonia nitrogen concentration of 100 to 1000 mg / L with a microorganism-supporting carrier and culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks. A culture process for preferentially culturing the group;
The cultured nitrifying bacteria group is brought into contact with the ammoniacal nitrogen-containing water having an ammoniacal nitrogen concentration of 1 to 100 mg / L in an aerobic atmosphere at 0 ° C. or more and 10 ° C. or less to thereby produce the ammoniacal nitrogen-containing water. And a nitrification step of nitrifying ammonia.   The method according to claim 2, wherein the microorganism holding carrier is an unfamiliar microorganism holding carrier. 4. The method according to any one of claims 1 to 3 , further comprising one or more additional nitrification steps. A treatment apparatus for water containing ammonia nitrogen,
A nitrification tank,
An introduction unit for introducing ammoniacal nitrogen-containing water having an ammoniacal nitrogen concentration of 1 to 100 mg / L into the nitrification tank;
A discharge section for discharging the ammoniacal nitrogen-containing water treated from the nitrification tank,
In the nitrification tank, a carrier in which a nitrifying bacteria group preferentially propagated by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks is included,
The processing apparatus which processes ammonia nitrogen containing water at 0 degreeC or more and 10 degrees C or less in the said nitrification tank. A treatment apparatus for water containing ammonia nitrogen,
A culture tank for culturing a group of nitrifying bacteria detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks;
A first introduction part for introducing ammonia nitrogen-containing water having an ammonia nitrogen concentration of 100 to 1000 mg / L into the culture tank;
A discharge section for discharging the nitrifying bacteria group cultured from the culture tank; and a nitrification tank connected to the discharge section;
A second introduction part for introducing ammonia nitrogen-containing water having an ammonia nitrogen concentration of 1 to 100 mg / L into the nitrification tank;
A discharge section for discharging the ammoniacal nitrogen-containing water treated from the nitrification tank,
Supplying the cultured nitrifying bacteria group from the culture tank to the nitrification tank via the discharge section;
The processing apparatus which processes ammonia nitrogen containing water at 0 degreeC or more and 10 degrees C or less in the said nitrification tank. The apparatus according to claim 6 , wherein the culture vessel contains a microorganism holding carrier. The apparatus according to any one of claims 5 to 7 , further comprising one or more additional nitrification tanks connected to the nitrification tank. A carrier;
A group of nitrifying bacteria preferentially propagated on the carrier, which is detected by culturing in a high concentration ammonia sulfate solution having a concentration of 5000 mg / L or more for 8 weeks,
A bacterial carrier for treating ammonia nitrogen-containing water having an ammonia nitrogen concentration of 1 to 100 mg / L at 0 ° C. or more and 10 ° C. or less.

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