JP4788645B2 - Method of using nitrite type nitrification carrier, wastewater treatment method and wastewater treatment apparatus - Google Patents

Description

  The present invention relates to a method for producing a nitrite-type nitrification carrier, a nitrite-type nitrification carrier, a wastewater treatment method, and a wastewater treatment apparatus. The present invention relates to a carrier production method, a nitrite type nitrification carrier, a wastewater treatment method, and a wastewater treatment apparatus.

  Biological treatment methods for treating wastewater and sewage with microorganisms are used in many treatment plants because of their relatively low cost. However, some microorganisms have a slow growth rate, are easily poisoned, or are difficult to grow in the environment. In particular, the nitrifying bacteria used when treating wastewater containing ammoniacal nitrogen has a problem that the growth rate is slow. Therefore, a method for fixing and treating a specific microorganism that is difficult to grow, such as nitrifying bacteria, has already been put into practical use.

As a method for immobilizing microorganisms, for example, as in Patent Document 1, a entrapping immobilization carrier that immobilizes microorganisms inside a gel is used. As microorganisms to be immobilized, activated sludge inhabiting nitrifying bacteria, lakes, rivers, sea bottom mud, surface soil, etc. are used as the source of microorganisms, especially activated sludge from factory wastewater and sewage treatment plants. The In addition, as in Patent Document 2, there is also used an adhesion-immobilized carrier that attaches microorganisms to the surface of the carrier material and immobilizes it. The carrier material is introduced into the activated sludge treatment and allowed to adhere to the surface naturally. Is used. Further, as disclosed in Patent Document 3, in a microorganism having viscosity such as nitrifying bacteria, granules can be formed by the self-granulating force of the microorganism itself, and there is an example in which the granules are used for wastewater treatment as a carrier.
Japanese Patent Laid-Open No. 11-33578 JP-A-8-267081 JP 2003-266095 A

  Conversion from nitric acid to nitrogen gas using denitrifying bacteria requires the addition of an organic substance such as methanol, which has the disadvantage of increasing running costs. For this reason, there has been a demand for a nitrogen removal method that requires only a small amount of organic matter.

  As a nitrogen removal method for solving this drawback, a nitrogen removal method by anaerobic ammonia oxidation has been attracting attention. This anaerobic ammonia oxidation method is a method in which ammonia is used as a hydrogen donor, nitrous acid is used as a hydrogen acceptor, and ammonia and nitrous acid are simultaneously denitrified by an anaerobic ammonia oxidizing bacterium according to the following reaction formula.

[Chemical 1]
NH4 ++ NO2− = N2 + 2H2O
According to this method, since ammonia is used as a hydrogen donor, there are merits such as drastically reducing the amount of methanol used for denitrification and reducing the amount of sludge generated. It is considered to be an effective method.

  In this anaerobic ammonia oxidation method, it is necessary to stop the oxidation of ammonia nitrogen in the middle and denitrify by leaving about half of nitrous acid and ammonia. However, the conventional entrapping immobilization carrier, adherent immobilization carrier or nitrification granule carrier used in the nitrite type nitrification reaction contains ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. In some cases, the reaction from nitrous acid to nitric acid is also passed.

  The present invention has been made in view of such circumstances, a nitrite-type nitrification carrier capable of greatly reducing the amount of organic matter added and lowering the running cost, a method for producing the same, a nitrogen removal method using the same, and An object is to provide an apparatus.

For the onset bright, to attain the aforementioned object, attachment immobilization carrier for immobilizing integrated sludge composite microorganism containing ammonia oxidizing bacteria and nitrite oxidizing bacteria even without small, granules entrapping immobilization pellets or self granule Le responsible body, (1) pH is 30 seconds or more is in a range of less than 2.0, (2) pH of 2.0 or more, 3 minutes or more in a range of less than 4.0, (3) pH of 4.0 As described above, nitrite type nitrification in which ammonia oxidizing bacteria are preferentially accumulated by acid treatment under any one of the conditions (1) to (3) of 15 minutes or more in the range of 6.0 or less Use as a carrier.

  Specific examples of complex microbial sludge having nitrification performance containing at least ammonia-oxidizing bacteria and nitrite-oxidizing bacteria include activated sludge from treatment plants that treat sewage and industrial wastewater, lakes, rivers, and sea bottom mud. There is soil on the surface.

According to the present invention, held in the form of either granules carrier ammonia oxidizing bacteria and attachment immobilization carrier integrated sludge complex microorganisms comprising nitrite-oxidizing bacteria, the entrapping immobilization pellets or self granules even without least The treated carrier was acid-treated within a pH range of 6.0 or lower. (The pH has a value of 0 or less, that is, minus (−). However, since there is no minus pH measurement technique, the lower limit value of the pH range is not defined here, and is described as pH 6 or less.) Ammonia-oxidizing bacteria Is highly resistant to acids, while nitrite-oxidizing bacteria have low resistance to acids, so that nitrite-oxidizing bacteria can be sterilized to preferentially accumulate ammonia-oxidizing bacteria. Further, in the present invention, the acid solution used for the acid treatment can be separated from the carrier and used repeatedly, so that energy loss can be reduced.

According to the present invention , by performing the acid treatment under the above-mentioned conditions, it is possible to sterilize nitrite-oxidizing bacteria and accumulate ammonia-oxidizing bacteria, and it is possible to produce a carrier that efficiently performs nitrite-type nitrification.

Waste water treatment apparatus of the present invention, anaerobic ammonia simultaneously denitrifying nitrite generation vessel that generates a nitrous acid from ammonia nitrite type nitrification carrier is turned, the ammonia and anaerobic ammonium oxidizing bacteria and nitrite An oxidization tank, and when the nitrite-type nitrification of the nitrite-type nitrification carrier has shifted to nitrate-type nitrification, it has a function of performing an acid treatment to recover the nitrite-type nitrification ability .

When nitrite-type nitrification of nitrite-type nitrification carrier has shifted to nitrate-type nitrification, according to the present invention , by performing acid treatment again, nitrite-oxidizing bacteria can be suppressed and nitrite-type nitrification ability can be recovered. it can. Even if nitrite-oxidizing bacteria are sterilized with an acid, if they are used for a long time, nitrite-oxidizing bacteria may re-grow. The growth of nitrite-oxidizing bacteria shifts nitrite-type nitrification to nitrate-type nitrification. In such a case, the nitrite-type nitrification ability can be recovered by sterilizing the nitrite-oxidizing bacteria again by acid treatment.

The wastewater treatment method for treating ammonia wastewater of the present invention includes a step of preferentially accumulating ammonia oxidizing bacteria on a nitrite type nitrification carrier by the above-described method, and the nitrite type preferentially accumulating ammonia oxidizing bacteria. It comprises a step of producing nitrous acid from ammonia in a nitrite production tank by a nitrification carrier, and a step of simultaneously denitrifying ammonia and the nitrous acid by anaerobic ammonia oxidizing bacteria in an anaerobic ammonia oxidation tank. To do.

According to the present invention , since the nitrite-type nitrification carrier in which ammonia-oxidizing bacteria are preferentially accumulated in the nitrite production tank is introduced, the activity of the nitrite-oxidizing bacteria can be selectively suppressed and the nitrite-type nitrification reaction can be performed. A wastewater treatment method that can be performed efficiently can be realized.

Waste water treatment method of the present invention, when the nitrite type nitrification of the nitrite-type nitrification carrier has moved to nitrate type nitrification, and characterized in that to restore the ability of the nitrite-type nitrification performing the acid treatment again To do.

According to the nitrite-type nitrification carrier , the wastewater treatment apparatus, and the wastewater treatment method according to the present invention, ammonia-oxidizing bacteria can be preferentially accumulated by sterilizing nitrite-oxidizing bacteria. Therefore, it is possible to provide a process that can be stopped by the oxidation reaction up to nitrous acid required in the anaerobic ammonia oxidation method. The acid solution used for sterilization of nitrite-oxidizing bacteria can be used repeatedly. A nitrite type nitrification carrier with low energy consumption can be produced.

  Further, when the nitrite-type nitrification carrier produced in the present invention is used with a wastewater treatment apparatus and treatment method, the oxygen supply and chemical addition amount can be greatly reduced, and the treatment time can be shortened.

  Further, when carrying out the wastewater treatment apparatus and treatment method using the nitrite type nitrification carrier produced in the present invention, the nitrite type nitrification ability can be maintained by carrying out acid treatment of the carrier periodically. .

  The preferred embodiments of the nitrite type nitrification carrier and the wastewater treatment method according to the present invention will be described in detail below with reference to the accompanying drawings.

The nitrite-type nitrification carrier of the present invention uses a complex microbial sludge mixed with a large number of microorganisms as a microbial supply source, such as sludge from lakes, rivers and seas, or activated sludge from sewage and factory wastewater treatment plants. Manufactured. In particular, it is preferable to use sludge containing a large amount of nitrifying bacteria such as ammonia oxidizing bacteria and nitrite oxidizing bacteria as a microorganism supply source.
As a method of holding and fixing sludge containing a microorganism supply source, a method of forming granules by adhesion fixation, comprehensive fixation, or self-granulating force is known. In the present invention, first, (1) the carrier material is put into the sludge of the complex microbial system and adhered and fixed, (2) the sludge of the complex microbial system is comprehensively fixed to the monomer or prepolymer, or (3) the complex microorganism The sludge containing the microorganism supply source is held and fixed by any one of the methods of forming granules by the self-granulating force of the sludge of the system.

  Next, the attached fixed carrier, the entrapped fixed carrier or the granule carrier produced in (1) to (3) is acid-treated at a pH of 6.0 or less, preferably at a pH of 0.5 to 5.0.

  In addition, after complex microbial sludge is acid-treated at a pH of 6.0 or less, preferably in the range of pH 0.5 to 5.0, (1) Is the carrier material introduced into the microbial sludge to be adhered and fixed? (2) The composite microbial sludge may be comprehensively fixed to the monomer or prepolymer, or (3) the granule may be formed by the self-granulating force of the composite microbial sludge.

  In this acid treatment method, the acid solution may be directly sprayed on the carrier for treatment, the carrier may be immersed in the acid solution, or the carrier may be stirred in the acid solution. In any of the acid treatment methods, it is necessary to carry out acid treatment at pH 6.0 or less, preferably in the range of pH 0.5 to 5.0. By the acid treatment, among a plurality of types of bacteria present in the sludge of the complex microbial system, nitrite-oxidizing bacteria with low acid resistance that nitrify nitrite into nitric acid are sterilized. Since nitrite-oxidizing bacteria are sterilized, highly acid-resistant ammonia-oxidizing bacteria that nitrify ammonia to nitrite are predominantly accumulated.

  As described above, the acid treatment is set to pH 6.0 or less, preferably within the range of pH 0.5 to 5.0. When pH is 5.0 or less, the bactericidal effect of nitrite-oxidizing bacteria is more reliably exhibited. Because it can. If the pH is 0.5 or more, the activity of ammonia oxidizing bacteria will rise without delay.

  In the production of the nitrite-type nitrification carrier of the present invention, as a carrier material used for adhesion fixation, polyvinyl alcohol, alginic acid, ethylene glycol-based gels, and plastic carriers such as cellulose, polyester, polypropylene, and vinyl chloride are preferably used. Can be used. Further, as the shape of the carrier material, a shape obtained by shaping a spherical shape, a cylindrical shape, a porous shape, a cubic shape, a honeycomb shape, or the like can be suitably used.

  In the production of the nitrite type nitrification carrier of the present invention, the carrier material used for comprehensive immobilization includes monomethacrylates, monoacrylates, dimethacrylates, diacrylates, trimethacrylates, triacrylates, tetraacrylates. In addition, urethane acrylates, epoxy acrylates, and the like, polyvinyl alcohol, acrylamide, photo-curable polyvinyl alcohol, photo-curable polyethylene glycol, photo-curable polyethylene glycol polypropylene glycol prepolymer, and the like can be used.

  Further, since nitrifying bacteria are easy to self-granulate due to their viscosity, granules can be formed by this self-granulating force and used as a carrier. In addition, the formation of granules includes not only those formed by self-granulating force but also granules formed in the form of adhering to the outer periphery of granules formed by other bacteria.

  In order to confirm the nitrite-type nitrification performance of the nitrite-type nitrification carrier produced by the production method of the present invention, a first wastewater treatment experiment was conducted by the following method.

  FIG. 1 is an explanatory diagram showing a schematic configuration of an experimental apparatus 1 used for the first wastewater treatment test.

  The experimental apparatus 1 includes a reaction tank 10 in which a large number of carriers 11, 11... Are charged, a raw water tank 13 in which waste water raw water is stored, a pH adjusting liquid tank 19 in which pH adjusting liquid is stored, and a pH adjuster 17. And. The reaction tank 10 and the raw water tank 13 and the reaction tank 10 and the pH adjusting liquid tank 19 are connected by piping. An air pump pipe 12 is disposed in the reaction tank 10. An outflow pipe 15 is provided in the reaction vessel 10 to flow out the treated wastewater. A pH electrode 16 is disposed to measure the pH of the reaction vessel 10, and the pH electrode 16 is connected to a pH adjuster 17.

  In the experimental apparatus 1, raw waste water flows from the raw water tank 13 into the reaction tank 10 by the power of the raw water pump 14. By the air supplied from the air pump pipe 12, the waste water raw water is agitated in the aeration together with the carriers 11, 11. The treated waste water is discharged as treated water from the outflow pipe 15 provided in the reaction tank 10.

  The pH value of the reaction vessel 10 is measured by the pH adjuster 17 through the pH electrode 16 provided in the reaction vessel 10. The pH adjustment pump 18 is driven based on an instruction from the pH adjuster 17 so that the pH value of the reaction tank 10 becomes constant. The pH adjusting liquid is supplied from the pH adjusting liquid tank 19 to the reaction tank 10 by the power of the pH adjusting pump 18.

  The nitrite-type nitrification carrier 11, 11 ... tested in this experiment was polymerized by mixing excess sludge from a sewage treatment plant with a polyethylene glycol prepolymer and adding potassium persulfide as a polymerization initiator. Thereafter, it was formed into a 3 mm cube and immersed in an acid solution having a pH of 2.0 to 2.2 for 10 minutes (hereinafter referred to as the carrier of the present invention). The sludge content was 2 W / V% and the prepolymer content was 10 V / V%. Moreover, 2 mol / L sulfuric acid was used for pH adjustment. The carriers 11, 11... After the acid treatment are taken out from the acid solution for neutralization and washed with tap water.

  The nitrite-type nitrification carriers 11, 11... Of the comparative example used in this experiment were manufactured by the same manufacturing method as described above. However, in the comparative example, the carriers 11, 11... Were manufactured by shaping them into 3 mm cubes and then immersing them in a solution of pH 7.5 to 7.7 for 10 minutes (hereinafter referred to as comparative carriers). This is the difference between the carrier of the present invention and the production method. Thereafter, the comparative carrier is taken out of the acid solution for neutralization in the same manner as the carrier of the present invention, and washed with tap water.

  The reaction volume of the reaction vessel 10 was 2 L, and the carrier 11 was filled in the reaction vessel 10 so that the carrier filling amount was 200 mL.

  Moreover, the synthetic waste water shown in Table 1 which simulated sewage was used as the waste water used in this experiment. The synthetic wastewater is adjusted so that the ammoniacal nitrogen concentration is 40 mg / L.

実験装置１０における廃水の水理学的滞留時間は３時間とした。吹き込むエア量が多く、反応槽１０内に吹き込むエアの溶存酸素（ＤＯ：Ｄｉｓｓｏｌｖｅｄ Ｏｘｙｇｅｎ）濃度が低いと亜硝酸型硝化になりうるので、反応槽１０中のＤＯを４．０ｍｇ／Ｌ以上に保持して廃水処理を行った。

The hydraulic residence time of the waste water in the experimental apparatus 10 was 3 hours. Since the amount of air to be blown is large and the dissolved oxygen (DO) concentration of the air to be blown into the reaction tank 10 is low, nitrite type nitrification can occur, so DO in the reaction tank 10 is kept at 4.0 mg / L or more. Then, wastewater treatment was performed.

  The result of the first wastewater treatment experiment is shown in FIG. FIG. 2A shows the test results when the carrier of the present invention is used, and FIG. 2B shows the test results when the comparative carrier is used. In each graph, ◯ indicates the ammonia nitrogen concentration of the raw water, ● indicates the ammonia nitrogen concentration of the treated water, ▲ indicates the nitrite nitrogen concentration of the treated water, and ■ indicates the nitrate nitrogen concentration.

  As shown in FIG. 2 (A), the activity of ammonia oxidizing bacteria was confirmed from the start in the wastewater treatment using the carrier of the present invention. A decrease in the ammonia nitrogen concentration of the treated water was observed, and an increase in the nitrite nitrogen concentration of the treated water was observed. On the other hand, no increase in nitrate nitrogen concentration was observed. From the start, nitrification of ammonia nitrogen started, and it was confirmed that nitrite type nitrification was performed. This is because nitrite-oxidizing bacteria are removed from the carriers 11, 11,... By acid treatment, and only nitrite-type nitrification by ammonia-oxidizing bacteria is performed.

  Thereafter, a complete nitrite type nitrification reaction was confirmed at 3 weeks. After the third week, it was confirmed that the ammonia nitrogen concentration was 5% or less and the nitrite nitrogen concentration was 25% or more. After 3 weeks from the start of the experiment, the nitrate nitrogen concentration showed a stable value of 5% or less, and no increase in concentration was observed.

  On the other hand, as shown in FIG. 2 (B), when wastewater treatment was performed with a comparative carrier, an increase in nitrate nitrogen concentration was observed from the second week, and formation of nitric acid was confirmed. The presence of nitrite-oxidizing bacteria was also confirmed. Furthermore, the nitrite nitrogen concentration and the nitrate nitrogen concentration showed the same value in the fifth week, and it was confirmed that the nitrate nitrogen concentration exceeded the nitrite nitrogen concentration after the fifth week. It was shown that the nitrification ability of nitrite-oxidizing bacteria exceeds that of ammonia-oxidizing bacteria.

  As shown in FIG. 2, it was shown that the support of the present invention, which was subjected to acid treatment after the support formation, could realize stable nitrite type nitrification.

  By the acid treatment, the nitrite type nitrification by the carriers 11, 11... In the first wastewater treatment test could be maintained for about 50 days. However, after that, it was confirmed that nitric acid was reduced and nitric acid was produced. This is thought to be because the nitrite-oxidizing bacteria that flowed in through the wastewater grew, and the small amount of nitrite-oxidizing bacteria that could not be treated by the acid treatment grew.

  Therefore, the carriers 11, 11,... Are taken out from the experimental device 1, and the carriers 11, 11 are immersed in an acid solution having a pH of 2.0 to 2.2 for 10 minutes, and then returned to the experimental device 1 to continue the waste water treatment. As a result, the nitrite type nitrification performance was recovered.

  Therefore, it has been found that the nitrite-type nitrification performance of the carrier can be maintained when a decrease in nitrous acid concentration or generation of nitric acid is observed, or when the carrier is acid-treated for a certain period.

  Next, a second wastewater treatment test was conducted in order to investigate the relationship between the acid solution pH and the acid treatment time in the method for producing a nitrite type nitrification carrier of the present invention.

  As the carrier to be tested, the same entrapping fixed carrier used in the first wastewater treatment test was used. The resulting entrapping immobilization carrier was acid-treated at pH 0, pH 0.5, pH 2.0, pH 3.0, pH 4.0, pH 5.0, pH 6.0, pH 7.0, with an acid treatment time of 6 seconds each. 30 seconds, 1 minute, 3 minutes, 9 minutes, 15 minutes, 30 minutes, and 60 minutes. In order to neutralize, the support after the acid solution treatment was once taken out from the acid solution and washed with tap water.

  Moreover, synthetic wastewater containing 40 mg / L of nitrogen nitrite was used as the wastewater to be tested. In the wastewater treatment test, 50 mg of carrier was put into 450 ml of synthetic wastewater, and wastewater treatment was performed by continuous aeration. The wastewater was changed every day, and the nitrous acid concentration and the nitric acid concentration in the changed treated water were measured.

  The result is shown in FIG. FIG. 3 (A) is a graph showing the concentration of nitrous acid in the treated water one month after the start of the experiment at each acid solution pH. On the other hand, FIG. 3 (B) is a graph showing the nitric acid concentration in the treated water one month after the start of the experiment at each acid solution pH.

  As can be seen from FIGS. 3 (A) and 3 (B), when the pH is less than 2.0, it is 30 seconds or more, when the pH is 2.0 or more and less than 4.0, 3 minutes or more, and when the pH is 4.0 or more and 6.0 or less. It was confirmed that by performing the acid solution treatment for 15 minutes or more, nitrite type nitrification in which nitric acid production was suppressed and nitrous acid production was promoted could be performed.

  As can be seen from FIGS. 3 (A) and 3 (B), when the pH is less than 2.0, it is 30 seconds or more, when the pH is 2.0 or more and less than 4.0, 3 minutes or more, and when the pH is 4.0 or more and 6.0 or less. It was found that by performing the acid solution treatment for 15 minutes or more, a nitrite-type nitrification carrier that performs nitrite-type nitrification can be produced and its nitrification ability can be maintained.

  FIG. 4 is a conceptual diagram showing an example of the overall configuration of the wastewater treatment apparatus of the present invention. As shown in FIG. 4, the wastewater treatment apparatus 20 includes a raw water pipe 21, a distributor 22 that distributes the raw water, a nitrous acid generation tank 23 to which a part of the raw water is supplied, and a downstream stage of the nitrous acid generation tank 23. An anaerobic ammonia oxidation tank 24 provided, a re-denitrification tank 25 provided downstream of the anaerobic ammonia oxidation tank 24, a methanol addition device 26 for supplying methanol to the re-denitrification tank 25, and a subsequent stage of the re-denitrification tank 25 The solid-liquid separation tank 27 is provided. A large number of the carrier 11 of the present invention is charged into the nitrous acid production tank 23. The nitrous acid production tank 23 is provided with an acid solution treatment tank 28 for treating the carrier 11 of the present invention with a reacid solution.

  The anaerobic ammonia oxidation tank 24 is configured to be supplied with a part of the raw water distributed by the distributor 22 in addition to the treatment liquid from the nitrous acid generation tank 23.

  In the waste water treatment apparatus 20, waste water containing ammonia nitrogen flowing through the raw water pipe 21 is distributed by the distributor 22, and a part of the waste water flows into the nitrous acid production tank 23. Ammonia in the ammoniacal wastewater that has flowed into the nitrous acid production tank 23 is aerated with the carrier of the present invention and oxidized to nitrous acid.

  The nitrite-treated water treated in the nitrous acid production tank 23 is supplied to the anaerobic ammonia oxidation tank 24 through a pipe. Further, a part of the ammonia waste water distributed by the distributor 22 is also supplied to the anaerobic ammonia oxidation tank 24. Ammonia and nitrous acid flowing into the anaerobic ammonia oxidation tank 24 are simultaneously denitrified by a denitrification reaction of anaerobic ammonia oxidizing bacteria.

  Since a slight amount of nitric acid remains in the treated water treated in the anaerobic ammonia oxidation tank 24, methanol is added from the methanol addition device 26 in the re-denitrification tank 25 to undergo solidification in the solid-liquid separation tank 27 through a denitrification reaction. The solution is separated and discharged out of the system as final treated water.

  In the nitrite-type nitrification carrier of the present invention, the ability to stop the reaction of ammonia nitrogen with nitrous acid is somewhat different depending on how it is used, but the nitrification ability may decrease with the passage of time. Accordingly, it is preferable that after the production of the nitrite-type nitrification carrier according to the present invention, the re-acid solution treatment is carried out periodically or after measuring the nitrite nitrogen concentration and nitrate nitrogen concentration to confirm the ability of nitrite nitrification. .

  By using the carrier of the present invention for the wastewater treatment apparatus 20, it is possible to obtain a stable denitrification process that can be stopped by the oxidation reaction up to nitrous acid required in the anaerobic ammonia oxidation method. The acid solution can be used repeatedly for sterilization of nitrite-oxidizing bacteria. A nitrite type nitrification carrier with low energy consumption can be produced.

Explanatory drawing which showed schematic structure of the experimental apparatus used for the 1st wastewater treatment test using the nitrite type nitrification support | carrier of this invention The graph which showed the relationship between the wastewater treatment time and each nitrogen concentration in wastewater in the 1st wastewater treatment test using this invention and the nitrite type nitrification support | carrier of a comparative example Graph showing nitrite concentration and nitric acid concentration at each pH and each acid solution treatment time using the nitrite type nitrification carrier of the present invention Conceptual diagram of a wastewater treatment apparatus using the nitrite type nitrification carrier of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Experimental apparatus, 10 ... Reaction tank, 11 ... Carrier, 13 ... Raw water tank, 17 ... Regulator, 19 ... pH adjustment liquid tank, 20 Waste water treatment apparatus, 23. ..Nitrous acid production tank, 24 ... anaerobic ammonia oxidation tank, 28 ... acid solution treatment tank

Claims (4)

Even without least attachment immobilization carrier for immobilizing integrated sludge composite microorganism containing ammonia oxidizing bacteria and nitrite oxidizing bacteria, granules responsible of entrapping immobilization pellets or self granulated material,
(1) 30 seconds or more when the pH is less than 2.0,
(2) When the pH is in the range of 2.0 or more and less than 4.0, 3 minutes or more,
(3) When the pH is in the range of 4.0 or more and 6.0 or less, 15 minutes or more,
(1) to (3), wherein the nitrite type nitrification carrier is preferentially accumulated with ammonia oxidizing bacteria by acid treatment under any one of the conditions. A wastewater treatment apparatus for treating ammonia wastewater,
Nitrite production tank nitrite type nitrification carrier that generates a nitrite is turned from ammonia,
An anaerobic ammonia oxidation tank that simultaneously denitrifies ammonia and nitrous acid by anaerobic ammonia oxidizing bacteria ,
A wastewater treatment apparatus comprising a function of recovering nitrite-type nitrification ability by performing acid treatment when nitrite-type nitrification of the nitrite-type nitrification carrier shifts to nitrate-type nitrification . A wastewater treatment method for treating ammonia wastewater,
A step of preferentially accumulating ammonia oxidizing bacteria on a nitrite type nitrification carrier by the method according to claim 1;
Producing nitrite from ammonia in a nitrite production tank by the nitrite type nitrification carrier preferentially accumulating ammonia oxidizing bacteria ;
A wastewater treatment method comprising a step of simultaneously denitrifying ammonia and the nitrous acid with anaerobic ammonia oxidizing bacteria in an anaerobic ammonia oxidizing tank. Wherein when the nitrite type nitrification nitrite type nitrification carrier has moved to nitrate type nitrification, wastewater treatment method 請 Motomeko 3 performing the acid treatment again Ru restored the nitrite type nitrification capacity.

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