JP2013013857A - Nitrification apparatus, and wastewater treating apparatus provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a running cost and an equipment investment cost as much as possible while sufficiently utilizing high nitrification treatment efficiency by an inclusively fixing carrier, and moreover, to allow easy introduction also to an existing wastewater treatment plant having no primary sedimentation basin.SOLUTION: In the nitrification apparatus 10 where ammonia nitrogen in wastewater is subjected to nitrification treatment by nitrifying bacteria under an aerobic condition to obtain nitrate nitrogen, there is provided at least one series of a sludge-carrier nitrification line 58 that has: a sludge nitrification tank 12 in which wastewater flows and ammonia nitrogen is nitrified by active sludge 18 containing nitrifying bacteria; a solid-liquid separation tank 14 in which solid in nitrified water subjected to nitrification treatment in the sludge nitrification tank 12 is subjected to solid-liquid separation to obtain supernatant water; and a carrier nitrification tank 16 in which the supernatant water flows and ammonia nitrogen remaining in the supernatant water is nitrified by the inclusively fixing carrier 30 for inclusively fixing the nitrifying bacteria to obtain final nitrification treatment water and further a carrier separation screen 36 of the inclusively fixing carrier 30 is provided.

Description

  The present invention relates to a nitrification apparatus and a wastewater treatment apparatus, and more particularly to a technique for constructing a nitrification apparatus for obtaining high nitrification treatment efficiency while suppressing running costs and equipment costs.

  As a waste water treatment apparatus for removing nitrogen from waste water containing ammonia nitrogen, an activated sludge circulation modification method has been conventionally known. The activated sludge circulation method is a treatment method using activated sludge. Waste water is sent to an aerobic nitrification tank through an anaerobic denitrification tank, and ammonia nitrogen is nitrated by nitrifying bacteria in the activated sludge in this nitrification tank. Nitrates (oxidizes) to reactive nitrogen. Then, a part of the nitrified water that has been nitrified is returned from the nitrification tank to the denitrification tank, and nitrate nitrogen is converted into nitrogen gas by denitrifying bacteria in the activated sludge. Moreover, the remainder of the treated water nitrified in the nitrification tank is discharged through the final sedimentation basin.

  However, the nitrification treatment with activated sludge has a problem that the nitrification bacteria cannot be maintained at a high concentration in the nitrification tank, so that a high load operation cannot be performed and the nitrification treatment efficiency is poor. For this reason, in recent years, a nitrification-promoting circulation modification method in which a carrier in which nitrifying bacteria are comprehensively immobilized is introduced into a nitrification tank has been performed (for example, Patent Document 1). As shown in FIG. 14, the nitrification promoting circulation modification method has the same basic configuration as the activated sludge circulation modification method, and the nitrification water nitrified in the nitrification tank 1 in which the entrapping immobilization carrier 4 is introduced is removed. The denitrification treatment is performed in the nitriding tank 2, and the treated water is separated into solid and liquid in the final sedimentation basin 3 and then discharged. However, since the nitrification tank 1 in which the entrapping immobilization carrier 4 is introduced is provided with a carrier separation screen 5 for preventing carrier outflow, clogging substances such as contaminants in the waste water are removed before the raw water of the waste water flows. The first settling basin 6 is essential. In this case, in order to improve the nitrification performance of the entrapping immobilization carrier, it is preferable to reduce the carrier particle size (for example, about 3 mm) and increase the specific surface area so that the carrier 4 does not flow from the nitrification tank 1. Requires a carrier separation screen 5 having a mesh width of about 1.5 to 2 mm. In this case, if the opening of the carrier separation screen 5 is increased so as to prevent clogging of impurities, the size of the carrier must be increased, so that the nitrification efficiency is reduced as described above.

JP 2008-012383 A

  As described above, the nitrification apparatus using the entrapping immobilization support can obtain higher nitrification efficiency than the nitrification apparatus using activated sludge, but has the following problems.

  (1) The cost for purchasing the entrapping immobilization carrier is required. Moreover, when the addition amount of the carrier increases, there is a demerit that the oxygen dissolution efficiency decreases and the aeration amount increases.

  (2) A solid-liquid separation tank (for example, a first sedimentation tank) for removing clogging substances such as contaminants in the wastewater is required in the front stage of the nitrification apparatus. There may be no sedimentation pond. Therefore, in order to install the nitrification equipment using the entrapping immobilization support, it is necessary to install the first sedimentation basin etc. to remove the impurities, which increases the equipment cost and secures the site for the first sedimentation basin. become.

  The present invention has been made in view of such circumstances, and it is possible to suppress running costs and capital investment costs as much as possible while fully utilizing the high nitrification treatment efficiency of the entrapping immobilization support, and to have an initial settling basin. It is an object of the present invention to provide a nitrification apparatus that can be easily introduced into an existing wastewater treatment plant that does not, and a wastewater treatment apparatus including the nitrification apparatus.

  In order to achieve the above object, the nitrification apparatus of the present invention is a nitrification apparatus in which ammonia nitrogen in waste water is nitrified under aerobic conditions by nitrifying bacteria to form nitrate nitrogen. Solid liquid to obtain supernatant water by solid-liquid separation of sludge nitrification tank that nitrifies ammonia nitrogen with activated sludge containing fungi, and solid content in nitrification water by activated sludge nitrified in the sludge nitrification tank Nitrogen nitrogen remaining in the supernatant water is nitrified by a entrapping immobilization carrier in which the supernatant water flows in and the nitrifying bacteria are entrapped and fixed to obtain a final nitrification treated water. And at least one series of sludge / carrier nitrification lines having a carrier nitrification tank provided with a carrier separation screen.

  In addition, entrapping and fixing nitrifying bacteria includes both cases where cultivated nitrifying bacteria are included and fixed and activated sludge containing nitrifying bacteria is included and fixed. Although not specifically stated, since the wastewater is not a synthetic wastewater, the wastewater contains impurities, BOD components and the like in addition to ammoniacal nitrogen.

  The present inventor clarifies sludge nitrification by sharing the nitrification of ammonia nitrogen in wastewater by sludge nitrification by activated sludge in the sludge nitrification tank and carrier nitrification by the entrapping immobilization support in the carrier nitrification tank. It was found that high nitrification efficiency can be obtained even if the residence time of the tank is shortened and the capacity (capacity) of the carrier nitrification tank is reduced.

  According to the nitrification apparatus of the present invention, nitrification of ammonia nitrogen in wastewater is performed, sludge nitrification is performed with activated sludge containing nitrifying bacteria in a sludge nitrification tank, and supernatant water from which solid matter is removed in a solid-liquid separation tank is obtained. . The supernatant water was subjected to carrier nitrification with a entrapping immobilization carrier in which nitrifying bacteria were entrapped and immobilized in a carrier nitrification tank.

  Thereby, compared to the case where all waste water is nitrified in the nitrification tank of the entrapping immobilization carrier, the usage amount of the entrapping immobilization carrier can be greatly reduced and the aeration amount can be reduced, so that the running equipment cost can be reduced. In addition, the capacity (capacity) of the carrier nitrification tank can be reduced, and the carrier nitrification tank has a solid-liquid separation tank in front of the carrier nitrification tank. Operation control is also facilitated without clogging with clogging substances such as foreign substances.

  Even better, the sludge nitrification tank and the solid-liquid separation tank (final sedimentation basin) are installed in the existing wastewater treatment plant as described in the prior art, so that the nitrification for the carrier is placed after the solid-liquid separation tank. If only the tank is newly installed, the nitrification apparatus of the present invention can be configured, and can be easily introduced into an existing wastewater treatment plant, and the equipment cost can be reduced.

  In the nitrification apparatus of the present invention, a bypass pipe that bypasses the carrier nitrification tank and bypasses the supernatant water to the treatment water pipe of the nitrification water, and ammonia nitrogen of the supernatant water and / or the nitrification water A nitrogen concentration meter for measuring the concentration, a supernatant water distributor for distributing the supernatant water to the nitrification tank for carrier and the bypass pipe, and controlling the supernatant water distributor based on the measurement result of the concentration meter, It is preferable to include a control means for adjusting the amount of supernatant water distributed to the carrier nitrification tank and the bypass pipe.

  The distribution ratio between the carrier nitrification tank and the bypass pipe by the supernatant water distributor includes the case where one is 100%.

  By configuring in this way, even if there are fluctuations in the concentration of ammoniacal nitrogen in the wastewater, fluctuations in the temperature of the wastewater, fluctuations in the wastewater flow rate, etc., the amount of supernatant water distributed to the nitrification tank for the carrier and the bypass pipe can be reduced. By controlling, load adjustment (for example, reduction of load) in the nitrification tank for carrier can be performed.

  As a result, it is possible not only to obtain a fixed nitrification water that meets the water quality standard, but also to eliminate the excessive operation of the carrier nitrification tank, thereby enabling more efficient operation.

  In this case, provided in parallel with the sludge / carrier nitrification line, the sludge nitrification line composed of the sludge nitrification tank and the solid-liquid separation tank, the sludge / carrier nitrification line, and the sludge nitrification line A wastewater distributor that distributes wastewater; a wastewater meter that measures the quality of the wastewater; and the wastewater distributor that is controlled based on the measurement results of the wastewater meter, the sludge / carrier nitrification line and the sludge nitrification line Control means for adjusting the distribution amount of wastewater distributed to each other, and a merging pipe that joins the supernatant water of the sludge / carrier nitrification line and the sludge nitrification line and introduces it into the nitrification tank for the carrier of the sludge / carrier nitrification line And more preferably.

  The distribution ratio between the sludge / carrier nitrification line and the sludge nitrification line by the wastewater distributor includes the case where one is 100%.

  This makes it possible to adjust the load applied to the sludge nitrification tank (for example, to reduce the load) according to the quality of the wastewater (for example, ammonia nitrogen concentration, water temperature, amount of water). Nitrification water can be obtained more efficiently.

  In this case, it is better to provide the carrier nitrification tank instead of the bypass pipe. Thereby, according to the quality of waste water (for example, ammonia nitrogen concentration, water temperature, amount of water), the load of carrier nitrification can be adjusted by the two carrier nitrification tanks. Thereby, flexibility improves compared with the case of bypass piping. Therefore, since it is possible to adjust the load in both the sludge nitrification tank and the carrier nitrification tank, it is possible to more efficiently obtain a fixed nitrification water that meets the water quality standard.

  In the nitrification apparatus of the present invention, a sludge nitrification line that is provided in parallel with the sludge / carrier nitrification line and includes the sludge nitrification tank and the solid-liquid separation tank, and a wastewater meter that measures the quality of the wastewater. Line selection means for performing line selection between the sludge / carrier nitrification line and the sludge nitrification line, and controlling the line selection means based on the measurement result of the wastewater meter, It is preferable to include a control unit that selects a line to be used from the sludge nitrification line.

  This is another mode for adjusting the load between the sludge nitrification tank and the carrier nitrification tank according to the quality of the wastewater (for example, the concentration of ammoniacal nitrogen, the water temperature, the amount of water), and has a nitrification tank for the carrier. The line to be used can be selected from the sludge / carrier nitrification line and the sludge nitrification line without the carrier nitrification tank.

  Thereby, since load adjustment of both the nitrification tank for sludge and the nitrification tank for support | carrier can be performed, the fixed nitrification water corresponding to a water quality standard can be obtained more efficiently.

  In the nitrification apparatus of the present invention, in the carrier nitrification tank, the entrapping immobilization carrier is stored in a container in which a plurality of water passage holes having a size that the entrapping immobilization carrier does not pass are formed to be flowable. In this state, it is preferable that the carrier nitrification tank is filled.

  Thereby, in the nitrification tank for carriers, the container flows by air aeration for making the inside of the tank aerobic, and further, the entrapping immobilization carrier flows in the container. By this double flow, the contact efficiency between the entrapping immobilization support and the waste water is improved, and the nitrification efficiency in the support nitrification tank can be improved. In this case, since a solid-liquid separation tank is provided in front of the carrier nitrification tank to remove clogging substances that clog the water passage holes of the container, clogging does not occur even if the water passage holes are small. Thereby, the entrapping immobilization carrier having a small carrier particle size and good nitrification efficiency can be stored in the container.

  Furthermore, since the mesh width of the carrier separation screen can be increased as compared with the case where a container is not used (when the entrapping immobilization carrier is directly introduced into the carrier nitrification tank), the carrier separation screen can be simplified, for example, commercially available. It is possible to use a metal mesh or punching metal.

  In order to achieve the above object, a wastewater treatment apparatus according to the present invention uses the nitrification apparatus according to any one of claims 1 to 7 and nitrate nitrogen in nitrification water nitrified by the nitrification apparatus. And a denitrification tank for denitrification under anaerobic conditions to convert to nitrogen gas.

  The present invention is configured as a wastewater treatment apparatus incorporating the nitrification apparatus of the present invention, and nitrate nitrogen in nitrification water treated by the nitrification apparatus is removed as nitrogen gas in a denitrification tank.

  In the wastewater treatment apparatus of the present invention, the denitrification tank is provided in the front stage of the nitrification apparatus, and a part of the final nitrification water treated in the nitrification tank for the carrier is circulated to the denitrification tank through a circulation pipe. It is preferred that

  By disposing the denitrification tank in the front stage of the nitrification apparatus, the organic matter in the wastewater can be efficiently used as a nutrient source for the denitrifying bacteria.

  In the wastewater treatment apparatus of the present invention, in addition to the denitrification tank, an auxiliary denitrification tank including a entrapping immobilization support in which the denitrifying bacteria are comprehensively fixed is provided at a subsequent stage of the nitrification apparatus, and is treated in the nitrification tank for the carrier. It is preferable to convert nitrate nitrogen remaining in the remaining final nitrification water into nitrogen gas in the auxiliary denitrification tank.

  Since a small amount of nitrate nitrogen remains in the final nitrification water treated in the carrier nitrification tank, it can be reliably converted to nitrogen gas in the auxiliary denitrification tank.

  As described above, according to the nitrification apparatus of the present invention and the wastewater treatment apparatus equipped with the nitrification apparatus, running costs and capital investment costs can be suppressed as much as possible while fully utilizing the high nitrification treatment efficiency by the entrapping immobilization support. Moreover, it can be easily introduced into an existing wastewater treatment plant that does not have a settling basin.

Basic configuration diagram of nitrification apparatus of the present invention Explanatory drawing of filling the carrier nitrification tank with the entrapping immobilization carrier stored in the container Explanatory drawing explaining 1st Embodiment of the nitrification apparatus of this invention Explanatory drawing explaining 2nd Embodiment of the nitrification apparatus of this invention Explanatory drawing explaining 3rd Embodiment of the nitrification apparatus of this invention Explanatory drawing explaining 4th Embodiment of the nitrification apparatus of this invention Illustration of wastewater treatment equipment incorporating a basic nitrification equipment Explanatory drawing of the wastewater treatment apparatus incorporating the nitrification apparatus of the first embodiment Explanatory drawing of the wastewater treatment equipment incorporating the nitrification device of the second embodiment Explanatory drawing of the wastewater treatment equipment incorporating the nitrification device of the third embodiment Explanatory drawing of the wastewater treatment equipment incorporating the nitrification device of the fourth embodiment Explanatory drawing of the waste water treatment equipment which provided the denitrification tank after the nitrification tank for the carrier Example graph using the nitrification apparatus of the present invention Illustration of a conventional nitrification-promoting circulation modification method

  Hereinafter, preferred embodiments of a nitrification apparatus according to the present invention and a wastewater treatment apparatus including the nitrification apparatus according to the present invention will be described in detail.

[Nitrification equipment]
(Basic configuration)
FIG. 1 is a basic configuration diagram of a nitrification apparatus 10 of the present invention.

  As shown in FIG. 1, the nitrification apparatus 10 of the present invention mainly includes a sludge nitrification tank 12, a solid-liquid separation tank 14, and a carrier nitrification tank 16. In FIG. 1, wastewater feeding means between the sludge nitrification tank 12, the solid-liquid separation tank 14, and the carrier nitrification tank 16 is omitted. In FIG. 1, the sludge nitrification tank 12, the solid-liquid separation tank 14, and the carrier nitrification tank 16 are illustrated as separate tanks. However, one tank is formed into an integral structure divided into three rooms. May be. Alternatively, the sludge nitrification tank 12 and the solid-liquid separation tank 14 may be divided into two tanks, and only the carrier nitrification tank 16 may be a separate tank.

  Waste water containing ammonia nitrogen first flows into the sludge nitrification tank 12 through the raw water pipe 11. The wastewater contains impurities, BOD components and the like in addition to ammoniacal nitrogen.

  Activated sludge 18 containing nitrifying bacteria floats in the tank of the sludge nitrification tank 12, and an aeration pipe 20 is disposed at the bottom of the tank, and the air sent from the blower 22 flows into the tank from the aeration pipe 20. Aerated. As a result, ammonia nitrogen in the wastewater is sludge nitrified with activated sludge under aerobic conditions.

  In addition, when constructing a wastewater treatment apparatus that nitrifies and denitrifies ammonia nitrogen wastewater by incorporating the nitrification apparatus 10 of the present invention, the wastewater is passed to the sludge nitrification tank 12 via the denitrification tank, as will be described later. It is preferable to be configured to flow in.

  Next, the sludge nitrification water that has been nitrified in the sludge nitrification tank 12 is sent to the solid-liquid separation tank 14. In the solid-liquid separation tank 14, the solid content of the sludge nitrification water, in particular, activated sludge and contaminants accompanying the sludge nitrification water from the sludge nitrification tank 12 is settled to separate the solid liquid into the supernatant water. obtain. The activated sludge and contaminants that have settled at the bottom of the solid-liquid separation tank 14 are partly discharged as surplus sludge through the sludge discharge pipe 24 and removed from the wastewater treatment device described later via the sludge return pipe 26. Returned to the slick tank.

  Next, the supernatant water obtained in the solid-liquid separation tank 14 is sent to the carrier nitrification tank 16. The tank of the carrier nitrification tank 16 is filled with a large number of entrapping immobilization carriers 30 entrapping and fixing nitrifying bacteria, and an aeration tube 32 is disposed at the bottom of the tank, so that the air sent from the blower 34 Aeration tube 32 aspirates the tank. Further, a carrier separation screen 36 for preventing the entrapping immobilization support 30 from flowing out along with the final nitrification water (hereinafter simply referred to as nitrification water) at the outflow portion of the nitrification water of the carrier nitrification tank 16. Is provided. As a result, the ammonia nitrogen remaining in the supernatant water is nitrified on the carrier under aerobic conditions, and the entrapping immobilization carrier 30 is prevented from flowing out along with the nitrification water.

  The nitrification treated water nitrified in the carrier nitrification tank 16 is sent to a denitrification tank of a wastewater treatment apparatus to be described later via a treated water pipe 38.

  As shown in FIG. 2, in the carrier nitrification tank 16, the entrapping immobilization carrier 30 is flowably accommodated in a container 33 in which a plurality of water passage holes 31 of a size that the carrier 30 does not pass are formed. Thus, the carrier nitrification tank 16 is preferably filled. The size of the container 33 is preferably in the range of 50 to 150 mm in diameter. The container 33 is composed of two hemispheres 33A and 33B obtained by dividing the sphere into two parts, and the hemispheres 33A and 33B are integrated by being fitted in the division part 35 or screwed together by a screw groove. The material of the container 33 is not particularly limited, but is preferably made of plastic in consideration of easiness of processing and specific gravity that allows the aeration air from the aeration pipe 32 to flow in the tank. And the specific gravity of the container 33 in the state in which the entrapping immobilization carrier 30 is accommodated is preferably in the range of 0.98 to 1.02. The carrier 30 to be stored has a specific gravity close to water of 0.98 to 1.02 in consideration of fluidity, and if it is smaller than this range, it floats on the liquid surface, and if larger, it sinks to the bottom of the tank. Aeration power is required. For this reason, the same applies to the specific gravity of the container.

  Further, it is preferable that the storage rate of the entrapping immobilization carrier 30 stored in the container 33 is 30% of the internal volume of the container 33. This is because when the storage rate exceeds 30%, the active flow of the entrapping immobilization carrier 30 in the container 33 is hindered.

  Thereby, the container 33 flows by the air aerated from the aeration pipe 32 in the carrier nitrification tank 16, and the entrapping immobilization carrier 30 flows in the container 33. By this double flow, the contact efficiency between the entrapping immobilization carrier 30 and the waste water is improved, and the nitrification efficiency in the carrier nitrification tank 16 can be improved.

  In this case, the solid-liquid separation tank 14 is provided in front of the carrier nitrification tank 16 so as to remove clogging substances that clog the water passage holes 31 of the container 33, so that the water passage holes 31 are not clogged. . Thereby, since the carrier particle size of the entrapping immobilization carrier 30 can be accommodated in the container 33 while being as small as 2 to 5 mm, high nitrification performance in the container 33 can be ensured.

  Furthermore, since the mesh width of the carrier separation screen 36 can be increased as compared with the case without the container 33, the carrier separation screen 36 can be simplified, for example, a commercially available wire mesh or punching metal can be used. . For example, when the size of the container 33 is 100 mm in diameter, it is sufficient that the container 33 of this size does not flow out. For example, a metal net or a punching metal having a 50 to 80 mm square hole can be used. As a result, the foreign matter does not adhere to the carrier separation screen 36 and is not clogged. Therefore, the operation controllability is the carrier separation screen when the entrapping immobilization carrier 30 of FIG. It becomes much easier than 36.

  As described above, in the nitrification apparatus 10 of the present invention, the nitrification of ammonia nitrogen in wastewater is shared by the sludge nitrification in the sludge nitrification tank 12 and the carrier nitrification in the support nitrification tank 16, as follows. Many benefits can be obtained.

  (A) Even if the residence time of the sludge nitrification tank 12 is shortened and the capacity (capacity) of the carrier nitrification tank 16 is reduced, high nitrification treatment efficiency can be obtained. As a result, when compared with the same quality standard of treated water, the residence time is slightly longer compared to the conventional nitrification-promoted circulation modified method in which all wastewater is nitrified in the nitrification tank of the entrapping immobilization support, but the conventional activated sludge The residence time can be halved compared with the circulation method. In addition, the amount of the entrapping immobilization carrier used can be greatly reduced and the amount of aeration can be reduced as compared with the conventional nitrification promotion type circulation modification method. As a result, the running cost can be reduced, and the capacity (capacity) of the carrier nitrification tank can be reduced to make it compact.

  Incidentally, when the activated sludge 18 and the entrapping immobilization support 30 are coexisting in one tank and nitrification is performed, the nitrification performance of the entrapping immobilization support 30 and the activated sludge 18 cannot be classified. Therefore, a large amount of entrapping immobilization support is required because the nitrification tank must be filled with an excess of entrapping immobilization support by design.

  (B) Further, by providing the solid-liquid separation tank 14 between the sludge nitrification tank 12 and the carrier nitrification tank 16, there is no activated sludge in the carrier nitrification tank 16 or even if it exists. It is a dripping amount. Therefore, the supernatant water has properties close to those of fresh water and has higher oxygen dissolution efficiency than ordinary activated sludge, so that the amount of air aeration in the carrier nitrification tank 16 can be reduced.

  (C) Since the solid-liquid separation tank 14 is provided in front of the carrier nitrification tank 16, the carrier separation screen 36 of the carrier nitrification tank 16 is not clogged with clogging substances such as contaminants in the wastewater. In this case, if the entrapping immobilization carrier 30 is housed in the container 33 as shown in FIG. 2, clogging of the water passage holes 31 formed in the container 33 can be prevented and the mesh width of the carrier separation screen 36 can be increased.

  (D) Since the sludge nitrification tank 12 and the solid-liquid separation tank 14 (for example, the final sedimentation basin) are provided in an existing wastewater treatment plant as described in the prior art, the existing sludge nitrification tank 12 and solid-liquid If only the nitrification tank for carrier is newly provided in the subsequent stage of the separation tank 14, the nitrification apparatus of the present invention can be configured. As a result, it can be easily introduced into an existing wastewater treatment plant and the equipment cost is reduced.

  (E) The carrier nitrification tank 16 has a lower concentration than the conventional activated sludge circulation modification method or the nitrification promotion circulation modification method in order to nitrify the remaining ammonia nitrogen that has been nitrified in the sludge nitrification tank 12. Ammonia nitrogen is nitrified. The entrapping immobilization carrier 30 can be nitrified at a high speed even for low-concentration ammoniacal nitrogen, and the quality of nitrification water can be improved.

  (F) The nitrification apparatus 10 of the present invention can be introduced into an existing wastewater treatment plant such as an activated sludge circulation modified method without modification, as well as an oxidation ditch method (OD method) or a sequence batch reactor method (SBR). Even existing wastewater treatment plants equipped with the Act) can be introduced without modification.

  Here, the entrapping immobilization carrier 30 will be described.

  The entrapping immobilization carrier 30 in the present invention is obtained by polymerizing an immobilization material mixed with microorganisms containing nitrifying bacteria, thereby immobilizing microorganisms in the immobilization material, and has a particle size of about 1 to 5 mm ( Usually 3 mm) is used. Examples of the immobilization material include polymer monomers, prepolymers, oligomers and the like, but are not particularly limited. For example, polyacrylamide, polyvinyl alcohol, polyethylene glycol, sodium alginate, carrageenan, agar, etc. may be used. it can. In addition, the following can be used for the prepolymer of the immobilization material.

  (Monomethacrylates) Polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, methacryloyloxyethyl hydrogen phthalate, methacryloyloxyethyl hydrogen succinate, 3chloro-2hydroxypropyl Methacrylate, stearyl methacrylate, 2-hydroxy methacrylate, ethyl methacrylate, etc.

  (Monoacrylates) 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobutyl acrylate, tbutyl acrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isobornyl acrylate, cyclohexyl acrylate, methoxytriethylene glycol acrylate, 2 ethoxy Ethyl acrylate, tetrahydrofurfuryl acrylate, phenoxy ethyl acrylate, nonyl phenoxy polyethylene glycol acrylate, nonyl phenoxy polypropylene glycol acrylate, silicon modified acrylate, polypropylene glycol monoacrylate, phenoxy ethyl acrylate, phenoxy diethylene glycol acrylate, phenoxy polyethylene Glycol acrylate, methoxy polyethylene glycol acrylate, acryloyl luer carboxyethyl hydrogen succinate, lauryl acrylate.

  (Dimethacrylates) 1,3 butylene glycol dimethacrylate, 1,4 butanediol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, butylene glycol dimethacrylate, hexanediol dimethacrylate , Neopentyl glycol dimethacrylate, polyprene glycol dimethacrylate, 2hydroxy 1,3 dimethacryloxypropane, 2,2bis4methacryloxyethoxyphenylpropane, 3,2bis4methacryloxydiethoxyphenylpropane, 2,2bis 4-methacryloxypolyethoxyphenylpropane and the like.

  (Diacrylates) Ethoxylated neopentyl glycol diacrylate, polyethylene glycol diacrylate, 1,6 hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2 bis 4-acryloxy Hiethoxyphenylpropane, 2-hydroxy 1-acryloxy 3-methacryloxy propane, and the like.

  (Trimethacrylates) Trimethylolpropane trimethacrylate and the like.

  (Triacrylates) Trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane EO addition triacrylate, glycerin PO addition triacrylate, ethoxylated trimethylolpropane triacrylate, and the like.

  (Tetraacrylates) Pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate and the like.

  (Urethane acrylates) Urethane acrylate, urethane dimethyl acrylate, urethane trimethyl acrylate, and the like.

  (Others) Acrylamide, acrylic acid, dimethylacrylamide.

  In addition, radical polymerization using potassium persulfate is optimal for the polymerization in the present invention, but polymerization using ultraviolet light or electron beam or redox polymerization may be used. In the polymerization using potassium persulfate, the amount of potassium persulfate added is preferably 0.001 to 0.25%, and an amine-based polymerization accelerator is preferably added to 0.001 to 0.5%. As the amine-based polymerization accelerator, β-dimethylaminopropionitrile, NNN′N ′ tetramethylethylenediamine, sodium sulfite and the like are preferable.

  The nitrifying bacteria to be entrapped and immobilized in the immobilization material may be purely cultured, but it is more preferable to entrap and immobilize activated sludge containing nitrifying bacteria. The reason for this is that oxygen dissolved in the immobilization material inhibits polymerization, but by entrapping and immobilizing activated sludge, activated sludge consumes oxygen and the polymerization reaction proceeds smoothly. The immobilization carrier 30 can be obtained.

  The nitrification apparatus 10 includes a sludge nitrification tank 12 and a carrier nitrification tank 16 in order to prevent fluctuations in the quality of nitrification water due to fluctuations in at least one factor of ammonia nitrogen concentration, water temperature, and water volume of wastewater. It is preferable to provide a load adjustment mechanism that performs load adjustment. Hereinafter, various aspects of the load adjustment mechanism will be described.

(First embodiment of nitrification apparatus equipped with load adjustment mechanism)
FIG. 3 shows a case where the load adjusting mechanism is provided only in the carrier nitrification tank 16.

  Since the basic configuration is the same as in FIG. 1, only the configuration different from that in FIG. 1 will be described.

  As shown in FIG. 3, the load adjusting mechanism bypasses the support nitrification tank 16 and bypasses the supernatant water to the treated water pipe 38, and the supernatant water is transferred to the support nitrification tank 16 and the bypass pipe 40. The supernatant water distributor 42 to be distributed, the first concentration meter 44A for measuring the ammonia nitrogen concentration of the supernatant water, the second concentration meter 44B for measuring ammonia nitrogen of the nitrification water, and the first and second concentrations The control unit 46 is configured to drive the supernatant water distributor 42 based on the measurement results of the measuring meters 44A and 44B to control the distribution ratio to the carrier nitrification tank 16 and the bypass pipe 40.

  Based on the ammonia nitrogen concentration of the supernatant water measured by the first concentration meter 44A and the ammonia nitrogen concentration of the treated water measured by the second concentration meter 44B, the control means 46 controls the nitrification tank 16 for the carrier. And the distribution ratio to be distributed to the bypass pipe 40 are controlled so that the nitrification water becomes constant at the target quality standard. The distribution ratio includes the case where one is 100% and the other is 0%.

  For example, when the temperature of the waste water is lowered as in the winter season, the nitrification activity of the activated sludge 18 is lowered, and therefore the remaining amount of ammonia nitrogen tends to increase in the supernatant water that has been nitrified in the sludge nitrification tank 12. Therefore, since the measurement result in the first concentration meter 44A becomes high, the control means 46 decreases the flow rate of the supernatant water flowing to the bypass pipe 40 and increases the flow rate to flow to the carrier nitrification tank 16. On the contrary, when the temperature of the wastewater is high and the nitrification activity of the activated sludge 18 is high as in the summer, the control means 46 increases the flow rate of the supernatant water flowing to the bypass pipe 40 and sets the flow rate to flow to the carrier nitrification tank 16. cut back. Thereby, the quality of the nitrification water can be kept constant regardless of the season. In summer, the amount of wasteful aeration can be reduced by reducing the amount of treated water to the carrier nitrification tank 16. Furthermore, by setting the flow rate on the bypass pipe 40 side to 100%, the operation of the carrier nitrification tank 16 can be stopped, and the running cost can be reduced.

  FIG. 3 is a diagram in which both the first concentration measuring meter 44A and the second concentration measuring meter 44B are provided, but either one of the first concentration measuring meter 44A or the second concentration measuring meter 44B is shown. Can also be provided.

(Second embodiment of nitrification apparatus equipped with load adjustment mechanism)
FIG. 4 shows a case where the load adjustment mechanism is provided in both the sludge nitrification tank 12 and the carrier nitrification tank 16, and the load adjustment mechanism on the carrier nitrification tank 16 side is the same as described in FIG. Therefore, explanation is omitted.

  As shown in FIG. 4, the load adjusting mechanism on the sludge nitrification tank 12 side is provided with a sludge / carrier nitrification line 58 including a sludge nitrification tank 12, a solid-liquid separation tank 14, and a carrier nitrification tank 16. The sludge nitrification line 60 composed of the nitrification tank 12 for use and the solid-liquid separation tank 14 is arranged in parallel. In other words, the sludge nitrification line 60 composed of the sludge nitrification tanks 12A and 12B and the solid-liquid separation tanks 14A and 14B is provided in parallel, and the support nitrification tank 16 provided with the bypass pipe 40 in the subsequent stage is provided. It is done. Then, the waste water is distributed to the two sludge nitrification lines 60 by the waste water distributor 50 and the branch pipe 52. The distribution ratio includes the case where one is 100%.

  In FIG. 4, two rows of sludge nitrification lines 60 are provided, but three or more rows may be used.

  The raw water pipe 11 is provided with at least one of a nitrogen concentration meter for measuring the ammonia nitrogen concentration of the waste water, a water temperature meter for measuring the temperature of the waste water, and a raw water meter for measuring the amount of the waste water, and the measured measurement results Is input to the control means 56. In addition, it is not essential to provide a nitrogen concentration meter, a water temperature meter, and a raw water meter, and a waste water factor meter having a large variation may be provided. Here, the case where the water temperature gauge 54 is provided will be described. Then, when the temperature of the waste water measured by the water temperature gauge 54 is low, the control means 56 controls the waste water distributor 50 to divide the waste water into two equal parts to the two rows of sludge nitrification lines 60.

  As a result, even if the temperature of the wastewater is low and the nitrification activity of the activated sludge 18 is significantly reduced as in winter, the load per tank of the sludge nitrification tank 12 is reduced. It can be prevented from dropping. On the other hand, when the temperature of the wastewater is high and the nitrification activity of the activated sludge 18 is high as in summer, the wastewater is allowed to flow through only one row of sludge nitrification lines 60.

  The supernatant water from the sludge nitrification line 60 is carrier nitrified in the carrier nitrification tank 16 equipped with a load adjusting mechanism.

  Thus, by providing a load adjustment mechanism in both the sludge nitrification tank 12 and the carrier nitrification tank 16, the nitrification water in accordance with a change in at least one factor of ammonia nitrogen concentration, water temperature, and amount of water in the wastewater. Water quality fluctuations can be prevented. In other words, this load adjusting mechanism means that the residence time of the waste water in the sludge nitrification tank 12 and the support nitrification tank 16 can be adjusted appropriately, and the residence time between the sludge nitrification and the carrier nitrification according to the quality of the waste water. Can be combined appropriately.

(Third embodiment of nitrification apparatus equipped with load adjustment mechanism)
The load adjusting mechanism of FIG. 5 is provided with nitrification tanks for carriers 16A and 16B in parallel in two rows instead of the bypass pipe 40 described in FIG. 4, and the supernatant water is supplied to the nitrification tanks for carriers 16A and 16B in two rows by the supernatant water distributor. It can be distributed. The distribution ratio includes the case where one is 100%.

  Thereby, when there is much residual amount of ammonia nitrogen concentration in the supernatant water, the supernatant water can be distributed to the two rows of nitrification tanks 16A and 16B for carriers to reduce the load per tank. Can be kept constant.

  Also in the case of FIG. 5, not only the water quality fluctuation of the nitrification water is prevented, but also the residence time of the waste water in the sludge nitrification tank 12 and the carrier nitrification tank 16 can be adjusted appropriately.

(Fourth embodiment of nitrification apparatus equipped with load adjustment mechanism)
The load adjusting mechanism of FIG. 6 has the carrier nitrification tank 16 instead of the method of adjusting the load by changing the distribution ratio by the waste water distributor 50 and the supernatant water distributor 42 as described in FIGS. The sludge / carrier nitrification line 58 and the sludge nitrification line 60 without the carrier nitrification tank 16 are arranged in parallel so that the line to be used is selected according to the quality of the wastewater.

  That is, as shown in FIG. 6, the load adjusting mechanism includes a sludge / carrier nitrification line 58 composed of a sludge nitrification tank 12, a solid-liquid separation tank 14, and a carrier nitrification tank 16, a sludge nitrification tank 12, and A sludge nitrification line 60 that is constituted by the solid-liquid separation tank 14 and does not have the carrier nitrification tank 16 is arranged in parallel.

  6A shows a combination of three rows of sludge / carrier nitrification lines 58 and one row of sludge nitrification lines 60, and FIG. 6B shows two rows of sludge / carrier nitrification lines 58 and two rows of sludge nitrification lines 60. FIG. 6C shows a combination of one row of sludge / carrier nitrification lines 58 and three rows of sludge nitrification lines 60.

  In FIG. 6, the total number of lines of the sludge / carrier nitrification line 58 and the sludge nitrification line 60 is four, but the present invention is not limited to this.

  6A, the raw water pipe 11 is branched into four branch pipes 62A, 62B, 62C, and 62D, and the three branch pipes 62A, 62B, and 62C are respectively provided with sludge and carrier nitrification lines. 58 are connected. The sludge nitrification line 60 is connected to the remaining one branch pipe 62D. Further, the three rows of sludge / carrier nitrification lines 58 and the one row of sludge nitrification lines 60 are joined to one treated water pipe 38 by a joining pipe 64.

  In addition, line selection means 66 is provided at the branch position of the raw water pipe 11, and the raw water pipe 11 has a concentration measuring means for measuring the ammonia nitrogen concentration in the waste water, a water thermometer for measuring the water temperature, and a water amount for measuring the water amount. At least one of the totals is provided. FIG. 6 shows the case where a water temperature gauge 54 is provided.

  And the control means 68 controls the line selection means 66 according to the water temperature of the waste water measured with the water temperature gauge 54, and selects the branch pipe to be used among the four branch pipes 62A, 62B, 62C, 62D. .

  This makes it possible to adjust the load between the sludge nitrification tank 12 and the carrier nitrification tank 16 according to the concentration of ammoniacal nitrogen in the wastewater, the water temperature, and the amount of water, so that the quality of the nitrification water is maintained constant. be able to.

  Also in the case of FIG. 6, not only the water quality fluctuation of the nitrification water is prevented, but also the residence time of the waste water in the sludge nitrification tank 12 and the carrier nitrification tank 16 can be adjusted appropriately.

  Next, the waste water treatment apparatus 70 incorporating the above-described various aspects of the nitrification apparatus 10 will be described.

[Waste water treatment equipment]
The waste water treatment apparatus 70 of FIG. 7 is a case where the nitrification apparatus 10 having the basic configuration shown in FIG. 1 is incorporated.

  As shown in FIG. 7, a denitrification tank 72 is provided in front of the sludge nitrification tank 12, and part of the nitrification water treated in the carrier nitrification tank 16 is circulated to the denitrification tank 72 via a circulation pipe 74. Is done. In the denitrification tank 72, activated sludge 76 containing denitrifying bacteria floats under anaerobic conditions, and nitrate nitrogen in the nitrification water is converted into nitrogen gas by contacting with the nitrification water. Further, the sludge settled in the solid-liquid separation tank 14 is returned to the denitrification tank 72 through the sludge return pipe 26.

  The waste water treatment apparatus 70 of FIG. 8 incorporates the nitrification apparatus 10 of the first embodiment shown in FIG. 3, and the waste water treatment apparatus 70 of FIG. 9 is the second embodiment shown in FIG. The nitrification apparatus 10 is incorporated. Further, the wastewater treatment apparatus 70 of FIG. 10 incorporates the nitrification apparatus 10 of the third embodiment shown in FIG. 5, and the wastewater treatment apparatus 70 of FIG. 11 is the fourth wastewater treatment apparatus 70 shown in FIG. The nitrification apparatus 10 of the embodiment is incorporated.

  In addition to the basic configuration of FIG. 7, the wastewater treatment apparatus 70 of FIG. 12 is provided with an auxiliary denitrification tank 80 after the carrier nitrification tank 16, and denitrifying bacteria are comprehensively fixed in the auxiliary denitrification tank 80 as a filler. This is the case where the entrapped entrapping immobilization carrier is filled. The filler may be a commonly used material such as plastic or sand. Although not shown, the organic source for denitrification can be supplemented by adding methanol or the like into the auxiliary denitrification tank 80.

  In the case of the wastewater treatment apparatus 70 of FIG. 12, since the SS component such as the activated sludge 18 is not accompanied by the nitrification tank 16 for the carrier by the solid-liquid separation tank 14, the carrier treatment is performed in the subsequent stage of the nitrification tank 16 for the carrier. An auxiliary denitrification tank 80 of the type can be provided. Incidentally, when the SS component is large, the filler is clogged, so it is not only necessary to perform backwashing frequently, but the SS component leaks into the treated water and causes water quality to deteriorate.

  Thereby, since a small amount of nitrate nitrogen remaining in the nitrification water treated in the carrier nitrification tank 16 can be converted into nitrogen gas, the quality of the final treated water after the auxiliary denitrification tank 80 can be improved, SS components such as activated sludge are not discharged in the final treated water.

  Although not shown in the figure, if the support treatment type auxiliary denitrification tank 80 is provided at the subsequent stage of the support nitrification tank 16, in the case of wastewater having a relatively low ammonia nitrogen concentration, It is possible to omit the nitriding tank 72 and the circulation pipe 74.

[Example]
(Test A)
Waste water treatment apparatus (Example) equipped with the nitrification apparatus of the present invention, waste water treatment apparatus of the conventional activated sludge circulation modified method (Comparative Example 1), and waste water treatment apparatus of the conventional nitrification promoting circulation modified method (Comparative Example) The residence time (HRT) in the nitrification line was compared for the three devices 2).

  In the comparative test, in order to obtain a treated water having an average of about TN 10 mg / L for waste water of the same water quality in which the total nitrogen concentration (TN) mainly composed of ammonia nitrogen is 40 mg / L in both Examples and Comparative Examples 1 and 2. The required HRT was compared.

  * The example used the configuration of the wastewater treatment apparatus of FIG.

  * Comparative Example 1 is a solid-liquid separation tank (first sedimentation basin) → denitrification tank (activated sludge) → nitrification tank (activated sludge) → solid-liquid separation tank (final sedimentation basin), and nitrification treatment obtained in the nitrification tank Part of the water was circulated through the denitrification tank.

  * Comparative Example 2 is the same as Comparative Example 1 except that the nitrification tank of Comparative Example 1 is changed from activated sludge to a entrapping immobilization support.

  In addition, the sludge density | concentration (MLSS) of the activated sludge in the denitrification tank in an Example and the comparative examples 1 and 2 and the sludge density | concentration in the nitrification tank of the comparative example 1 were set to 2000 mg / L. The nitrification tank of the present invention and Comparative Example 2 was filled with a entrapping immobilization support so as to have a volume of 10%. In addition, the dissolved oxygen (DO) by air aeration in the nitrification tank is set to 3 mg / L in the examples, 1 and 2, and the circulation ratio for circulating the nitrification water to the denitrification tank is as in the examples 1 and 2. Both are the same.

<Test results>
* In the examples of the present invention, the HRT of the sludge nitrification tank was HRT of 8 hours + the HRT of the support nitrification tank was 1 hour, for a total of 9 hours.

  * Comparative Example 1 by the conventional activated sludge circulation modified method had HRT of the nitrification tank of 12 to 16 hours.

  * In Comparative Example 2 using the conventional nitrification-promoting circulation modification method, the HRT of the nitrification tank was 6 to 8 hours. In addition, there was a tendency for impurities in the wastewater to be clogged with the carrier separation screen (mesh width 1.5 mm), and maintenance was complicated compared to the present invention.

  As can be seen from the above results, the HRT of the nitrification line in the present invention is slightly longer than Comparative Example 2 in which all of the wastewater is nitrified only with the entrapping immobilization support, but all of the wastewater is nitrified only with activated sludge. The HRT can be greatly shortened as compared with Comparative Example 1 to be performed.

  Further, in the embodiment of the present invention, the residence time in the carrier nitrification tank can be set to 1 hour, so that the nitrification tank capacity can be remarkably compact as compared with Comparative Example 2, and accordingly, The filling amount of the immobilization carrier can be greatly reduced. The sludge nitrification tank and solid-liquid separation tank (final sedimentation basin) are provided in the existing wastewater treatment plant. Therefore, if only the support nitrification tank is installed after the solid-liquid separation tank, the existing wastewater treatment tank will be installed. It can respond without modifying the place.

(Test B)
In activated sludge, the nitrification rate is unlikely to decrease during the summer when the wastewater temperature is high, but the nitrification rate tends to decrease during the winter when the wastewater temperature is low. Therefore, using activated sludge and the entrapping immobilization support, the nitrification treatment efficiency assuming a winter wastewater temperature (11 to 16 ° C.) was compared.

  As a result, the nitrification rate of activated sludge was 1 mg / g-SS · h on average, while the nitrification rate of the entrapping immobilization carrier was 80 mg / L-carrier · h on average.

  Then, the activated sludge is filled in the nitrification tank so as to be 2000 mg / L in MLSS, and the entrapping immobilization carrier is filled in the nitrification tank of the same capacity so as to have a volume of 10%. The speed was examined.

  As a result, the nitrification tank filled with activated sludge was 48 mg / L-nitrification tank / day, whereas the nitrification tank of the entrapping immobilization support was 192 mg / L-nitrification tank / day. From this result, in the winter when the waste water temperature is low, the nitrification tank filled with the entrapping immobilization support is overwhelmingly faster than the nitrification tank filled with activated sludge.

  For this reason, the amount of entrapped immobilization carrier used can be greatly reduced by placing a small carrier nitrification tank with a smaller capacity (capacity) than the nitrification-promoting circulation method after the sludge nitrification tank. In addition, this is particularly effective for winter measures where the temperature of the waste water is low and the activity of the activated sludge is likely to decrease.

(Test C)
Test C examined the ability of the nitrification apparatus of the present invention, which combines sludge nitrification and carrier nitrification, to cope with fluctuations in ammoniacal nitrogen of wastewater. In the test, when nitrification water from an existing sewage treatment plant (using the activated sludge circulation modified method) is drawn into the test plant of the nitrification tank for the carrier via the test line, the ammonia nitrogen concentration in the wastewater fluctuates. Was investigated. The temperature of the waste water was 11 to 21 ° C., and the HRT of the nitrification tank for carrier (filling immobilization carrier 10% filling rate) was set to 1 hour. The result is shown in FIG.

  As can be seen from FIG. 13, the ammoniacal nitrogen in the nitrification water from the sewage treatment plant varied from about 0 to about 19 mg / L. However, as shown in FIG. 13 (A), the concentration of ammoniacal nitrogen in the nitrification water treated in the configuration of sludge nitrification tank → solid-liquid separation tank → support nitrification tank is 5 mg / L or less, which is the treatment water standard. Could be abbreviated. This result shows that the nitrification rate is stable at about 70% even when the ammoniacal nitrogen concentration in the wastewater raw water varies from 0 to 20 mg / L. This means that even in winter when the activity of nitrifying bacteria in the activated sludge in the sludge nitrification tank is reduced, a small-capacity carrier nitrification tank is placed downstream of the sludge nitrification tank, so that It shows that 5 mg / L or less can be achieved.

On the other hand, FIG. 13B shows the result when the inflow rate into the carrier nitrification tank is changed according to the ammonia concentration (NH ₄ -N concentration) of the raw water. Specifically, when the NH ₄ -N concentration in the raw water is 10 mg / L or less, the flow into the bypass pipe is started, and the lower the NH ₄ -N concentration in the raw water is, the lower the flow rate into the carrier nitrification tank is Reduced and processed. As can be seen from FIG. 13 (B), the NH ₄ —N concentration of the treated water could be reduced to 5 mg / L or less even when the inflow to the bypass pipe was used together. In this case, as a matter of course, since the amount of treatment in the carrier nitrification tank is small, energy such as aeration power can be saved.

  DESCRIPTION OF SYMBOLS 10 ... Nitrification apparatus, 12 ... Sludge nitrification tank, 14 ... Solid-liquid separation tank, 16 ... Carrier nitrification tank, 18 ... Activated sludge, 20 ... Aeration pipe, 22 ... Blower, 24 ... Sludge discharge piping, 26 ... Sludge return Piping, 30 ... entrapping immobilization carrier, 31 ... water passage hole, 32 ... aeration pipe, 33 ... container, 34 ... blower, 35 ... dividing part, 36 ... carrier separation screen, 38 ... treated water piping, 40 ... bypass piping, 42 ... Supernatant water distributor, 44A ... first concentration meter, 44B ... second concentration meter, 46 ... control means, 50 ... waste water distributor, 52 ... branch pipe, 54 ... water thermometer, 56 ... control means, 58 ... Sludge / carrier nitrification line, 60 ... sludge nitrification line, 62A, 62B, 62C, 62D ... branch pipe, 64 ... confluence pipe, 66 ... line selection means, 68 ... control means, 70 ... waste water treatment device, 72 ... denitrification tank ( Activated sludge), 74 ... circulation piping, 6 ... activated sludge, 80 ... denitrification tank (the entrapping immobilization pellets)

Claims (10)

In the nitrification device, ammonia nitrogen in wastewater is nitrified by nitrifying bacteria under aerobic conditions to make nitrate nitrogen,
The sludge nitrification tank into which the wastewater flows and nitrifies the ammoniacal nitrogen with the activated sludge containing the nitrifying bacteria,
A solid-liquid separation tank that obtains supernatant water by solid-liquid separation of the solid content in the nitrification water by the activated sludge that has been nitrified in the sludge nitrification tank;
The supernatant water flows in, the ammonia nitrogen remaining in the supernatant water is nitrified by the entrapping immobilization support in which the nitrifying bacteria are entrapped and the final nitrification treated water is obtained, and the entrapping immobilization support carrier separation screen A nitrification tank for the carrier provided;
A nitrification apparatus comprising at least one series of sludge / carrier nitrification lines having Bypass piping that bypasses the nitrification tank for the carrier and bypasses the supernatant water to the treated water piping of the nitrified water;
A nitrogen concentration meter for measuring the ammonia nitrogen concentration of the supernatant water and / or the nitrification water;
A supernatant water distributor for distributing the supernatant water to the carrier nitrification tank and the bypass pipe;
The control device for controlling the supernatant water distributor based on the measurement result of the concentration meter and adjusting the amount of supernatant water distributed to the nitrification tank for carrier and the bypass pipe. 2. The nitrification apparatus according to 1. A sludge nitrification line that is provided in parallel with the sludge / carrier nitrification line, and is constituted by the sludge nitrification tank and the solid-liquid separation tank;
A waste water distributor for distributing the waste water to the sludge / carrier nitrification line and the sludge nitrification line;
A wastewater meter for measuring the quality of the wastewater;
Control means for controlling the wastewater distributor based on the measurement result of the wastewater meter, and adjusting the amount of wastewater distributed to the sludge / carrier nitrification line and the sludge nitrification line;
3. A merging pipe that joins the supernatant water of the sludge / carrier nitrification line and the sludge nitrification line and introduces it into the nitrification tank for the carrier of the sludge / carrier nitrification line. Nitrification equipment.   4. The nitrification apparatus according to claim 3, wherein the carrier nitrification tank is provided in place of the bypass pipe. The sludge nitrification line is provided in parallel with the sludge / carrier nitrification line, and is configured from the sludge nitrification tank and the solid-liquid separation tank;
A wastewater meter for measuring the quality of the wastewater;
Line selection means for performing line selection between the sludge / carrier nitrification line and the sludge nitrification line;
Control means for controlling the line selection means based on the measurement result of the wastewater meter, and selecting a line to be used from the sludge / carrier nitrification line and the sludge nitrification line, The nitrification apparatus according to claim 1.   The nitrification apparatus according to any one of claims 3 to 5, wherein the quality of the wastewater is at least one of ammonia nitrogen concentration, water temperature, and amount of water. In the carrier nitrification tank,
The entrapping immobilization carrier is filled in the carrier nitrification tank in a state in which the entrapping immobilization carrier is flowably accommodated in a container formed with a plurality of water passage holes of a size that does not allow the inclusion immobilization carrier to pass through. The nitrification apparatus according to any one of claims 1 to 6, wherein: The nitrification apparatus according to any one of claims 1 to 7,
A waste water treatment apparatus comprising: a denitrification tank that converts nitrate nitrogen in nitrification water nitrified by the nitrification apparatus into nitrogen gas by denitrification treatment under anaerobic conditions by denitrifying bacteria. .   The denitrification tank is provided in a stage preceding the nitrification apparatus, and a part of the final nitrification water treated in the nitrification tank for the carrier is circulated to the denitrification tank through a circulation pipe. The waste water treatment apparatus according to 8.   In addition to the denitrification tank, an auxiliary denitrification tank including a entrapping immobilization support in which the denitrification bacteria are entrapped and fixed is provided at a subsequent stage of the nitrification apparatus, and remains in the remainder of the final nitrification water treated in the nitrification tank for the support. The wastewater treatment apparatus according to claim 9, wherein nitrate nitrogen to be converted is converted to nitrogen gas in the auxiliary denitrification tank.

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