JP2010005517A - Method and apparatus for manufacturing nitrite-type nitrification reaction carrier, wastewater treatment method and wastewater treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for manufacturing nitrite-type a nitrification reaction carrier capable of surely carrying out nitrite-type nitrification reaction at a low cost, and a wastewater treatment method and apparatus. <P>SOLUTION: The apparatus 90 for manufacturing the nitrite-type nitrification reaction carrier includes a washing device 94 for washing a deposited immobilized carrier formed by depositing sludge of a composite microorganism system comprising ammonia-oxidizing bacteria and nitrite-oxidizing bacteria and having nitrification performance on a carrier material, an included immobilized carrier formed by including the sludge of the composite microorganism system in the carrier material, or a nitrification granular carrier formed by self-granulating capacity of the sludge of the composite microorganism system with alkaline water, and manufactures the nitrite-type nitrification reaction carrier in which the ammonia-oxidizing bacteria for oxidizing ammonia nitrogen to nitrous acid are dominantly accumulated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a manufacturing method, a manufacturing apparatus, a wastewater treatment method, and a wastewater treatment apparatus for a nitrite-type nitrification reaction carrier, and in particular, a nitrite-type nitrification reaction carrier for performing a nitrite-type nitrification reaction before anaerobic ammonia oxidation. The present invention relates to a method and an apparatus for manufacturing the waste water and a waste water treatment method and apparatus using the same.

  In wastewater treatment facilities, activated sludge inhabiting nitrifying bacteria, sludge from lakes, rivers and sea, sludge from water treatment plants, surface soil, etc. are used as the source of microorganisms, and these microorganisms are immobilized on the carrier. Has been used. As a method for immobilizing microorganisms, for example, as in Patent Document 1, a entrapping immobilization carrier in which microorganisms are immobilized in a gel is used. 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 in Patent Document 3, a microorganism having viscosity such as nitrifying bacteria can form granules 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.

  By the way, in recent years, wastewater treatment facilities have been developed that simultaneously denitrify ammonia and nitrous acid in wastewater by anaerobic ammonia oxidizing bacteria. In this wastewater treatment facility, it is necessary to perform a reaction (hereinafter referred to as a nitrite-type nitrification reaction) that stops ammonia gas from being oxidized to nitric acid without oxidizing ammonia nitrogen to nitric acid as a preceding stage of the anaerobic ammonia oxidation reaction.

Therefore, conventionally, the nitrite type nitrification reaction was controlled by treatment with a high concentration ammonia load, low concentration dissolved oxygen concentration, high pH adjustment, and high water temperature.
Japanese Patent Laid-Open No. 11-33578 JP-A-8-267081 JP 2003-266095 A

  However, in the conventional method, it is necessary to continue to supply energy for the nitrite type nitrification reaction, and there is a problem that an energy saving advantage obtained by anaerobic ammonia oxidation is offset.

  The present invention has been made in view of such circumstances, a method for manufacturing a nitrite type nitrification reaction carrier capable of reliably performing a nitrite type nitrification reaction at low cost, a manufacturing apparatus, a wastewater treatment method, and An object is to provide a wastewater treatment apparatus.

  In order to achieve the above object, the invention described in claim 1 is a production method for producing a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria that oxidize ammoniacal nitrogen to nitrite are preferentially accumulated. Adhesion-immobilized support formed by adhering a sludge of a complex microbial system having ammonia-oxidizing bacteria and nitrite-oxidizing bacteria having a nitrification performance to a carrier material, formed by including the sludge of the complex microorganism system in a carrier material It is characterized by comprising an alkali washing step of washing the entrapped immobilization carrier or the nitrification granule carrier formed by the self-granulating force of the complex microorganism sludge with alkaline water.

  The inventor of the present invention can improve the performance of the nitrite-type nitrification reaction of the support and maintain the performance for a long period only by washing the support on which the sludge of the complex microorganism system is immobilized with alkaline water. Obtained knowledge. The present invention has been made on the basis of this finding. Since the carrier on which the sludge of the complex microorganism system is immobilized is washed with alkaline water, the nitrite type nitrification reaction carrier in which ammonia-oxidizing bacteria are preferentially accumulated Is obtained. Further, in the present invention, since the carrier is only washed with alkaline water, it is not necessary to constantly supply energy for the nitrite type nitrification reaction, and the cost can be reduced.

  According to a second aspect of the present invention, in the first aspect of the invention, the alkaline cleaning step controls the pH of the alkaline water to 9.0 or more. The inventor of the present invention can promote sterilization of nitrite-oxidizing bacteria (that is, bacteria that oxidize nitrite to nitric acid) by washing the carrier with alkaline water having a pH of 9.0 or more. The knowledge that the efficiency of nitrification reaction can be improved was obtained. The present invention has been made based on such knowledge, and since the pH of the alkaline water was set to 9.0 or more, the performance of the nitrite type nitrification reaction of the support can be promoted. Further, alkaline water having a pH of 9.0 or more can be repeatedly used for alkali cleaning, and energy and cost consumption can be reduced. In addition, the upper limit of pH is preferably less than 14 in order to prevent inactivation of ammonia oxidizing bacteria and increase the degree of accumulation.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the alkali cleaning step is performed for 1 minute or more when the pH of the alkaline water is 12 or more and less than 14, and the pH is 10 or more and less than 12. Is performed for 5 minutes or longer, and is performed for 20 minutes or longer when the pH is in the range of 9.0 to less than 10. By performing alkaline water washing under the above conditions, nitrite oxidizing bacteria can be excluded and ammonia oxidizing bacteria can be reliably accumulated, and ammonia oxidizing bacteria can be prevented from being deactivated by contact with excessive alkaline water. Thereby, the support | carrier which performs a nitrite type nitrification reaction efficiently can be manufactured.

  In order to achieve the above object, a manufacturing apparatus for manufacturing a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria that oxidize ammonia nitrogen to nitrite are preferentially accumulated is provided. Adhesion-immobilized support formed by adhering a sludge of a complex microbial system having ammonia-oxidizing bacteria and nitrite-oxidizing bacteria having a nitrification performance to a carrier material, formed by including the sludge of the complex microorganism system in a carrier material It is characterized by comprising an alkali washing device for washing the entrapped immobilization carrier or the nitrification granule carrier formed by the self-granulating force of the complex microorganism sludge with alkaline water. The present invention is an apparatus invention for carrying out the above-described method invention. Since the carrier is washed with alkaline water, a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria are preferentially accumulated can be obtained.

  In order to achieve the above object, the invention according to claim 5 oxidizes ammonia nitrogen in waste water to nitrite by a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria are preferentially accumulated. And an anaerobic ammonia oxidation step in which ammonia and nitrous acid in the treated water obtained in the nitrous acid production step are simultaneously denitrified by anaerobic ammonia oxidation bacteria, in the wastewater treatment method, the nitrite production step Is an adhering immobilization support formed by adhering a sludge of a complex microbial system having nitrification performance containing at least ammonia-oxidizing bacteria and nitrite-oxidizing bacteria to a carrier material, and including the complex microbial sludge in the carrier material. To wash the entrapped immobilization carrier formed or the nitrification granule carrier formed by the self-granulating force of the complex microbial sludge with alkaline water. Which comprises using a nitrite-type nitrification reaction carrier obtained I.

  According to the present invention, since the nitrite type nitrification reaction is performed using the nitrite type nitrification reaction carrier washed with alkaline water, it is not necessary to continuously supply energy for the nitrite type nitrification reaction, thereby reducing the cost. be able to.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, in the nitrite production step, when the nitrite type nitrification reaction carrier shifts from a nitrite type nitrification reaction to a nitrate type nitrification reaction, the nitrite type The nitrification reaction carrier is washed with alkaline water. According to the present invention, since the cleaning is performed when the performance of the nitrite type nitrification reaction carrier is lowered, the performance of the nitrite type nitrification reaction carrier can always be maintained high.

  In order to achieve the above object, the invention according to claim 7 is a nitrite production tank in which a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria that oxidize ammonia nitrogen to nitrite are preferentially accumulated is introduced. And an anaerobic ammonia oxidation tank that is disposed downstream of the nitrous acid production tank and simultaneously denitrifies ammonia and nitrous acid by anaerobic ammonia oxidizing bacteria, in the nitrous acid production tank The nitrite type nitrification reaction carrier is provided with an alkali cleaning device for cleaning with alkaline water.

  According to the present invention, the nitrite type nitrification reaction carrier in the nitrous acid production tank can be washed with alkaline water by the alkali washing device. Therefore, wash the nitrite-type nitrification reaction carrier before use with alkaline water to improve its performance, or wash the nitrite-type nitrification reaction carrier in use with alkaline water to restore performance. Can do.

  According to the present invention, since the carrier on which the sludge of complex microorganisms is immobilized is washed with alkaline water, a nitrite-type nitrification reaction carrier on which ammonia-oxidizing bacteria are preferentially accumulated is obtained. It is not necessary to supply energy continuously for the nitric acid type nitrification reaction, and the cost can be reduced.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of a manufacturing method, a manufacturing apparatus, a wastewater treatment method, and a wastewater treatment apparatus according to the present invention will be described below with reference to the accompanying drawings.

  First, the first test that is the theoretical basis of the present invention will be described. FIG. 1 shows the experimental apparatus used in the first test. In the figure, each tank is shown in a transparent state.

  As shown in FIG. 1, the experimental apparatus 10 includes a reaction tank 12, and a large number of carriers 14, 14. The reaction tank 12 is connected to a raw water tank 18 through a raw water pipe 16. Synthetic waste water simulating sewage is stored in the raw water tank 18. By driving the raw water pump 20 on the raw water pipe 16, the synthetic waste water in the raw water tank 18 is sent to the reaction tank 12 through the raw water pipe 16. To be liquidated.

  An adjustment liquid tank 24 is connected to the reaction tank 12 via an adjustment liquid pipe 22. An adjustment liquid pump 26 is disposed in the adjustment liquid pipe 22, and the pH adjustment liquid in the adjustment liquid tank 24 is sent to the reaction tank 12 by driving the adjustment liquid pump 26.

  An air pump pipe 28 is disposed inside the reaction tank 12. The air pump pipe 28 is connected to an air supply means (not shown), and air is supplied to the air pump pipe 28 by the air supply means. When air is supplied to the air pump pipe 28, air is diffused from the lower end of the air pump pipe 28, and aeration and agitation are performed. That is, when the air bubbles diffused from the lower end of the air pump pipe 28 rise, the carriers 14, 14... Flow and agitate, and air is supplied to the carriers 14, 14. .

  A pH electrode 30 is disposed inside the reaction vessel 12. The pH electrode 30 is connected to a pH adjuster 32 so that the pH in the reaction vessel 12 can be measured. The pH adjuster 32 is connected to the adjustment liquid pump 26, and the drive of the adjustment liquid pump 26 is controlled based on the measured value of the pH adjuster 32. That is, the adjustment liquid pump 26 is driven so that the inside of the reaction tank 12 has a desired pH, and the pH adjustment liquid is supplied to the reaction tank 12. Thereby, the inside of the reaction vessel 12 can be controlled to a desired pH.

  In this experiment, surplus sludge from a sewage treatment plant was mixed with a polyethylene glycol-based prepolymer, polymerized by adding potassium persulfide as a polymerization initiator, and shaped into a 3 mm square cube. The carrier 14 was sludge-encapsulated so that the sludge content was 2 W / V% and the prepolymer content was 10 V / V%. Moreover, the synthetic | combination waste water in the raw | natural water tank 18 used what was shown to the table | surface of FIG. 2, and prepared and used it so that it might become 40 mg / L as ammoniacal nitrogen concentration. Furthermore, 1 mol / L sulfuric acid was used as the pH adjusting solution in the adjusting solution tank 24. In addition, the reaction tank 12 having a reaction volume of 2 L was used, and the reaction tank 12 was filled with the carrier 14 so that the carrier filling amount was 200 mL.

  In the experimental apparatus 10 configured as described above, first, the support 14 was immersed in an acid solution having a pH of 12 for 1 minute to produce a nitrite type nitrification reaction support (hereinafter referred to as the present invention support). In addition, as a comparative example, a entrapping immobilization carrier (hereinafter referred to as a comparison carrier) immersed in a pH 7.5 solution for 10 minutes was produced.

  After production of the carrier, wastewater treatment was performed by adjusting the pH in the reaction vessel 12. At that time, since the nitrite type nitrification reaction occurs when the pH is high, the pH in the reaction tank 12 was adjusted to 7.0 to 7.5.

  The results are shown in FIGS. 3 (A) and 3 (B). FIG. 3A shows the case where the carrier of the present invention is used, and FIG. 3B shows the case where a 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 of the treated water. ing.

  As can be seen from FIG. 3B, when wastewater treatment is performed with the comparative carrier, ammonia nitrogen in the treated water decreases after about one week, and nitrite nitrogen in the treated water increases instead. However, after two weeks, the amount of nitrogen nitrite in the treated water has decreased and the amount of nitric acid has increased instead. Therefore, it can be seen that when a comparative carrier is used, nitrite-oxidizing bacteria increase inside the comparative carrier, so that the nitrite type nitrification reaction cannot be performed stably.

  On the other hand, in the case of the carrier of the present invention, as shown in FIG. 3 (A), after about one week, ammonia nitrogen in the treated water decreases, and instead nitrite nitrogen increases. Nitrite nitrogen was obtained in the treated water for at least 7 weeks. Therefore, it can be seen that when the carrier of the present invention is used, ammonia-oxidizing bacteria are stably produced in the carrier and the nitrite type nitrification reaction can be carried out stably.

  Thus, it turns out that the support | carrier of this invention wash | cleaned with alkaline water can perform a nitrite type nitrification reaction reliably, and can perform the nitrite nitrification reaction stably for a long period of time.

  Next, as a second test, the relationship between the alkaline water pH and the alkaline water washing time when the carrier of the present invention was produced was determined.

  As the carrier 14 (before alkali washing) used in this test, the same carrier as that used in the first test was used, and this carrier was adjusted to pH 8, 9, 10, 11, 12, 13, 13.5, 14. Washed with alkaline water. Moreover, the carrier was produced with alkaline water washing times of 0, 1, 3, 5, 10, 20, 40 and 60 minutes, respectively. In order to neutralize after the production of the carrier, the carrier 14 after washing with alkaline water was once taken out from the alkaline water and washed with tap water.

  Moreover, synthetic wastewater containing 40 mg / L of nitrite nitrogen was used as the wastewater to be tested. In the wastewater treatment test, 50 mL of carrier was added to 450 mL of this 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 results are shown in FIGS. 4 (A) and 4 (B). FIG. 4A shows the nitrous acid concentration in the treated water one month after the start of the experiment, and FIG. 4B shows the nitric acid concentration in the treated water one month after the start of the experiment.

  As can be seen from these figures, when the pH of the alkaline water was in the range of 12 to 14, the production of nitric acid was suppressed and the production of nitrous acid was promoted when the washing time was 1 minute or longer. Similarly, when the pH of the alkaline water is in the range of 10 or more and less than 12, the production of nitric acid was suppressed and the production of nitrous acid was promoted when the washing time was 5 minutes or more. Furthermore, when the pH of the alkaline water was 9 or more and less than 10, the production of nitric acid was suppressed and the production of nitrous acid was promoted when the washing time was 20 minutes or more. Therefore, the nitrite type nitrification reaction can be efficiently performed by controlling the pH of alkaline water and the washing time as described above.

  In the above test, nitrous acid concentration and nitric acid concentration were measured, and it is known that these concentrations are proportional to the number of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. That is, the number of bacteria is measured by a method called MPN method. In this method, a solution in which a carrier is crushed is diluted stepwise with an ammonia medium or a nitrite medium, and microbial cells are produced from the production of nitrous acid or nitric acid. The concentration is estimated and calculated. Therefore, the increase / decrease in nitrite concentration and nitrate concentration in the test corresponds to the increase / decrease in ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in the carrier, and is an index of the performance of the nitrite-type nitrification reaction of the carrier.

  Next, an embodiment of a wastewater treatment apparatus made based on the above-described theoretical basis will be described.

  FIG. 5 schematically shows the configuration of the waste water treatment apparatus 50 of the present embodiment, and shows only the nitrous acid production tank 54 that is a characteristic part of the present invention in detail.

  As shown in the figure, the waste water treatment apparatus 50 is mainly composed of a raw water tank 52, a nitrous acid production tank 54, and an anaerobic ammonia oxidation tank 56. A raw water pipe 58 is connected to the raw water tank 52, and wastewater is supplied to the raw water tank 52 through the raw water pipe 58 and stored. The wastewater stored in the raw water tank 52 is sent to the distributor 60 via the pipe 59. Two pipes 62 and 64 are connected to the distributor 60, one pipe 62 is connected to the mixer 66 through the nitrous acid production tank 54, and the other pipe 64 is directly connected to the mixer 66. The

  A large number of nitrite-type nitrification reaction carriers 68, 68,... This nitrite type nitrification reaction carrier 68 is the same as the carrier of the present invention used in the above-described test, and adheres sludge of a complex microorganism system having nitrification performance including ammonia oxidizing bacteria and nitrite oxidizing bacteria to the carrier material. Adhesion-immobilized support formed by mixing, composite microbial sludge encapsulated in a carrier material, or nitrified granule support formed by self-granulating force of composite microbial sludge Was washed with alkaline water. At the time of washing, the pH of the alkaline water is 9 or more and less than 14, and the washing time is 1 minute or more when the pH of the alkaline water is 12 or more and less than 14, and 5 minutes or more when the pH of the alkaline water is 10 or more and less than 12. The pH of the alkaline water was 20 minutes or more in the range of 9 or more and less than 10.

  By this nitrite type nitrification reaction carrier 68, ammoniacal nitrogen contained in the waste water in the nitrous acid production tank 54 is oxidized to nitrous acid. The wastewater treated in the nitrous acid production tank 54 is sent to the mixer 66 via the pipe 62 and mixed with the wastewater sent directly from the distributor 60. The above-described distributor 60 performs a diversion in the mixer 66 so that the molar ratio of ammonia to nitrous acid in the waste water is approximately 1: 1.32. In the present embodiment, the waste water in the raw water tank 52 is divided into two, and after one of the waste water is subjected to nitrite type nitrification reaction, it is mixed with the other waste water. However, the present invention is not limited to this. Alternatively, the nitrite type nitrification reaction may be performed so that a predetermined concentration of nitrous acid is generated without diversion.

  The waste water mixed by the mixer 66 is sent to the anaerobic ammonia oxidation tank 56. The anaerobic ammonia oxidation tank 56 is loaded with a carrier on which anaerobic ammonia oxidizing bacteria are immobilized. Anaerobic ammonia-oxidizing bacteria are said to be a group of bacteria represented by Planctonmycete, and the culture method includes nonwoven fabrics (Hajime Ikuta, Kazuichi Isaka, Tatsuo Tsunono (2004), anaerobic ammonia by a continuous culture system. A method of acclimatizing oxidized bacteria, see 38th Annual Meeting of Water Environment Society, p372), culturing by attaching to a filter bed, etc., peeling off the biofilm is preferable. In addition, anaerobic ammonia-oxidizing bacteria can be fixed in a fixed manner in an immobilizing material such as a gel, a method of attaching and fixing to an adherent carrier such as plastic or nonwoven fabric, and a biofilm is formed on the plastic carrier and fixed. Methods, methods used as granules, and the like can be used, and as a carrier immobilization material, polyvinyl alcohol, alginic acid, polyethylene glycol-based gel, and the like can be used. The shape of the carrier is preferably a spherical shape, a cylindrical shape, a cubic shape or the like, and the size of the carrier is preferably a 1 mm to 5 mm size spherical shape, a cylindrical shape, a cubic shape, or the like.

  By the above-mentioned anaerobic ammonia oxidizing bacteria, ammonia and nitrous acid contained in the waste water in the anaerobic ammonia oxidizing tank 56 are simultaneously denitrified. The denitrified treated water is discharged from the anaerobic ammonia oxidation tank 56.

  By the way, the nitrous acid production tank 54 is provided with a pH adjusting liquid tank 70 and a cleaning tank 72 as a cleaning device for the nitrite type nitrification reaction carrier 68. The washing tank 72 is connected to the nitrous acid production tank 54 via the carrier transfer device 73, and the carrier transfer apparatus 73 allows the nitrite type nitrification reaction carrier 68 before washing in the nitrous acid production tank 54 to be washed. 72.

  The cleaning tank 72 is connected to the pH adjusting liquid tank 70 through a pipe 80. Alkaline water is stored in the pH adjusting liquid tank 70, and the alkaline water in the pH adjusting liquid tank 70 is supplied to the cleaning tank 72 by driving a pump 81 provided in the pipe 80. The cleaning tank 72 is provided with a pH sensor 74, and the pH in the tank is measured by the pH sensor 74. The above-described pump 81 is controlled based on the measured value of the pH sensor 74, and the inside of the cleaning tank 72 is controlled to a desired pH (9 or more and less than 14). Thereby, the nitrite type nitrification reaction carrier 68 in the washing tank 72 can be washed with alkaline water. The carrier transfer device after a predetermined time has passed after washing (that is, 1 minute or more when the pH is 12 or more and less than 14, 5 minutes or more when the pH is 10 or more and less than 12, or 20 minutes or more when the pH is 9 or more and less than 10). 73 is driven, and the nitrite type nitrification reaction carrier 68 is transferred to the nitrite production tank 54. As a result, the nitrite type nitrification reaction carrier 68 that has been subjected to alkali cleaning for a predetermined time is returned to the nitrous acid production tank 54, so that the nitrite type nitrification ability of the nitrite type nitrification reaction carrier 68 can be recovered. . The nitrite type nitrification reaction carrier 68 is preferably cleaned periodically. That is, it is preferable that a part of the nitrite-type nitrification reaction carrier 68 in the nitrous acid production tank 54 is periodically pulled out, transferred to the washing tank 72, washed with alkaline water, and then returned to the nitrous acid production tank 54.

  The nitrous acid generation tank 54 is provided with a nitric acid concentration sensor 85, and the nitric acid concentration sensor 85 measures the nitric acid concentration in the tank. The nitric acid concentration sensor 85 is connected to the control device 86, and the control device 86 drives and controls the carrier transfer device 73 based on the measurement value of the nitric acid concentration sensor 85. Specifically, when the concentration of nitric acid in the tank increases, it is determined that “the nitrite-type nitrification reaction carrier 68 has shifted from the nitrite-type nitrification reaction to the nitrate-type nitrification reaction”, and the nitrite-type nitrification reaction carrier 68 The amount of transfer to the cleaning tank 72 is increased. Thereby, the nitrite type nitrification reaction carrier 68 in the nitrite production tank 54 always maintains a high nitrite type nitrification capacity.

  Thus, according to the waste water treatment apparatus 50, since the nitrite type nitrification reaction carrier 68 can be washed with alkaline water, the nitrite type nitrification reaction can always be performed efficiently.

  In the waste water treatment apparatus 50 of FIG. 5, the pH adjusting liquid tank 70 is connected to the nitrous acid generation tank 54 via a pipe 82, and the pH adjusting liquid tank 70 is driven by driving a pump 83 disposed in the pipe 82. The alkaline water therein is supplied to the nitrous acid production tank 54. The nitrous acid production tank 54 is provided with a pH sensor 84, and the pump 83 is controlled based on the measured value of the pH sensor 84. Therefore, the nitrous acid production tank 54 can be controlled to a desired pH, and the nitrite type nitrification reaction carrier 68 can be washed with alkali in the nitrous acid production tank 54.

  In the above-described embodiment, the nitrite-type nitrification reaction carrier 68 previously washed with alkaline water is introduced into the nitrous acid production tank 54. However, the present invention is not limited to this, and the carrier before washing is washed. 72 may be used for alkali cleaning.

  Further, in the above-described embodiment, the nitric acid concentration sensor 78 is provided in order to determine that “the nitrite type nitrification reaction carrier 68 has shifted from the nitrite type nitrification reaction to the nitric acid type nitrification reaction”. A concentration sensor may be provided to measure the nitrous acid concentration. In this case, the change in the reaction can be determined by the decrease in the concentration of nitrous acid.

  Next, an apparatus 90 for producing a nitrite-type nitrification reaction carrier to which the present invention is applied will be described. As shown in FIG. 6, the manufacturing apparatus 90 includes a carrier molding device 92 and a cleaning device 94.

  The carrier molding device 92 is a device for molding a carrier from a carrier raw material (fixing agent, water, activated sludge, polymerization initiator, etc.), for example, a complex microorganism having nitrification performance including ammonia oxidizing bacteria and nitrite oxidizing bacteria. Self-granulating power of the adhesion-immobilized support formed by adhering the sludge of the system to the carrier material, the entrapping immobilization support formed by including the sludge of the complex microbial system in the support material, or the sludge of the complex microbial system The nitrified granule carrier formed by the above is molded. The method for forming the carrier is not particularly limited. For example, a sheet molding method is used in which a mixture of microorganisms and a polymer material is formed into a sheet shape, and the rectangular carrier is produced by finely cutting the mixture. In addition, a mixture of microorganisms and polymer material is injected into a vinyl tube of several millimeters in diameter and extruded while polymerizing, and this is cut into a certain length to produce a cylindrical carrier, or a microorganism and A dropping granulation method in which a mixture of molecular materials is dropped into another liquid to produce a spherical carrier may be used.

  The carrier formed by the carrier forming device 92 is sent to the cleaning device 94. The cleaning device 94 cleans the carrier by immersing the carrier in alkaline water or by showering the carrier with alkaline water. At that time, the alkaline water preferably has a pH of 9 or more and less than 14 as described in the above-described test. The washing time is set to be 1 minute or more when the pH is 12 or more and less than 14, 5 minutes or more when the pH is 10 or more and less than 12, and 20 minutes or more when the pH is 9 or more and less than 10.

  According to the manufacturing apparatus 90 configured as described above, since the molded carrier is washed with alkaline water, the performance of the nitrite type nitrification reaction is good and the nitrite type nitrification reaction can be continued. A nitrite type nitrification reaction carrier can be produced. This nitrite type nitrification reaction carrier is put into the nitrous acid production tank 54 of the waste water treatment apparatus 50 described above.

  In the above-described embodiment, the carrier molding device 92 and the cleaning device 94 are continuously provided. However, the present invention is not limited to this, and the cleaning device 94 is provided separately from the carrier molding device 92. Also good. Further, in the process of forming the carrier by the carrier molding device 92, the carrier (or a sheet before becoming a carrier) may be washed with alkaline water.

The figure which shows the experimental apparatus used in the test used as the rationale of this invention Table showing the composition of the synthetic wastewater used in the test Diagram showing test results Diagram showing test results Configuration diagram schematically showing a wastewater treatment apparatus to which the present invention is applied The block diagram which shows the manufacturing apparatus with which this invention was applied

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Experimental apparatus, 12 ... Reaction tank, 14 ... Carrier, 16 ... Raw water piping, 18 ... Raw water tank, 20 ... Raw water pump, 22 ... Adjustment liquid piping, 24 ... Adjustment liquid tank, 26 ... Adjustment liquid pump, 28 ... Air pump , 30 ... pH electrode, 32 ... pH controller, 50 ... Waste water treatment device, 52 ... Raw water tank, 54 ... Nitrous acid production tank, 56 ... Anaerobic ammonia oxidation tank, 58 ... Raw water piping, 60 ... Distributor, 62 ... Piping, 64 ... Piping, 66 ... Mixer, 68 ... Nitrite type nitrification reaction carrier, 70 ... pH adjusting liquid tank, 72 ... pH adjusting liquid tank, 74 ... pH sensor, 76 ... Control device, 78 ... Nitric acid concentration sensor, 90 ... Manufacturing device, 92 ... Carrier molding device, 94 ... Cleaning device

Claims (7)

In a production method for producing a nitrite-type nitrification support in which ammonia-oxidizing bacteria that oxidize ammonia nitrogen to nitrite are preferentially accumulated,
An adhering immobilization support formed by adhering a sludge of a complex microbial system having nitrification performance containing at least ammonia-oxidizing bacteria and nitrite-oxidizing bacteria to a carrier material, and formed by including the complex microbial sludge in a carrier material. A nitrite-type nitrification reaction comprising an alkaline washing step of washing the entrapped immobilization carrier or the nitrification granule carrier formed by the self-granulating force of the complex microorganism sludge with alkaline water A method for producing a carrier.   2. The method for producing a nitrite-type nitrification reaction carrier according to claim 1, wherein in the alkali cleaning step, the pH of the alkaline water is controlled to 9.0 or more.   The alkali cleaning step is performed for 1 minute or more when the pH of the alkaline water is 12 or more and less than 14, and is performed for 5 minutes or more when the pH is 10 or more and less than 12, and the pH is in the range of 9.0 or more and less than 10. Then, the method for producing a nitrite-type nitrification reaction carrier according to claim 1, wherein the method is performed for 20 minutes or longer. In a production apparatus for producing a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria that oxidize ammonia nitrogen to nitrite are preferentially accumulated,
An adhering immobilization support formed by adhering a sludge of a complex microbial system having nitrification performance containing at least ammonia-oxidizing bacteria and nitrite-oxidizing bacteria to a carrier material, and formed by including the complex microbial sludge in a carrier material. A nitrite type nitrification reaction comprising an alkaline cleaning device for cleaning a entrapped immobilization carrier or a nitrification granule carrier formed by the self-granulating force of the complex microbial sludge with alkaline water Carrier production equipment. A nitrite production process in which ammonia nitrogen is oxidized to nitrite by a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria are preferentially accumulated;
In the wastewater treatment method comprising: an anaerobic ammonia oxidation step in which ammonia and nitrous acid in the treated water obtained in the nitrous acid production step are simultaneously denitrified by anaerobic ammonia oxidizing bacteria,
The nitrite production step includes an adhering immobilization support formed by adhering a composite microbial sludge having nitrification performance containing at least ammonia-oxidizing bacteria and nitrite-oxidizing bacteria to a support material, and the composite microbial sludge as a support. Nitrite-type nitrification reaction obtained by washing with alkaline water a entrapping immobilization carrier formed by inclusion in the material or a nitrification granule carrier formed by the self-granulating force of the sludge of the above complex microorganism system A wastewater treatment method using a carrier.   In the nitrous acid production step, when the nitrite-type nitrification reaction carrier shifts from a nitrite-type nitrification reaction to a nitrate-type nitrification reaction, the nitrite-type nitrification reaction carrier is washed with alkaline water. Processing method. A nitrite production tank into which a nitrite-type nitrification reaction carrier in which ammonia-oxidizing bacteria that oxidize ammonia nitrogen to nitrous acid are preferentially accumulated, and a rear stage of the nitrite production tank are disposed, In an anaerobic ammonia oxidation tank that simultaneously denitrifies nitrous acid with anaerobic ammonia oxidizing bacteria,
A wastewater treatment apparatus comprising an alkali cleaning device for cleaning the nitrite type nitrification carrier in the nitrous acid production tank with alkaline water.

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