JP2015229131A - Effluent treatment apparatus and effluent treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effluent treatment apparatus capable of holding anaerobic ammonia oxidation (anammox) microorganisms highly densely in a treatment tank in a short time.SOLUTION: There is provided an effluent treatment apparatus A which performs effluent treatment by using anammox microorganisms, in which a fixed bed carrier 2 is arranged in a treatment tank 1, the fixed bed carrier 2 includes a slender core part, and a large number of ring-shaped bodies which are erected from the whole peripheral surface of the core part and each of which is formed by bending fiber yarns and closing both ends, and the anammox microorganisms as an aggregate are attached/fixed on the fixed bed carrier 2 as they are, so that the anammox microorganisms can be held highly densely in the treatment tank 1 in a short time, and start-up time of a nitrogen removal treatment apparatus by anammox reaction can be significantly shortened. Further, an effluent treatment apparatus may be constituted that anammox microorganisms and nitrous-acid microorganisms are held on the fixed bed carrier 2, and a biofilm 29 with a diameter 10 mm or more is formed.

Description

  In the present invention, a fixed bed carrier in which a large number of ring-shaped bodies formed by bending a fiber yarn and closing both ends thereof is provided over the entire outer periphery of a slender core portion is disposed in a treatment tank, and fixed. The present invention relates to a wastewater treatment apparatus, a wastewater treatment method, and the like that retain anammox microorganisms on a floor carrier and treat wastewater in a treatment tank.

  Wastewater such as domestic wastewater, human waste, industrial wastewater, and agricultural / livestock wastewater contains a lot of pollutants such as organic matter, solid matter, and nutrient salts. Released into water bodies. In general, wastewater treatment is performed by selecting a treatment method according to the characteristics of the pollutant components contained in the wastewater, a treatment target, and the like, and combining a plurality of treatment methods.

  Among them, for example, the activated sludge method is a method of decomposing / removing organic substances and the like by the action of aerobic microorganisms in the activated sludge, and is most often used in sewage treatment plants and the like. In this method, generally, after removing solids from sewage at the first sedimentation site, aerobic microorganisms in the activated sludge decompose organic matter in the aeration tank, and sludge and water are removed from the final sedimentation site. Separate the precipitate. The collected sludge is returned to an aeration tank or treated as sewage sludge, and the separated water is discharged into public water areas after chlorination.

  In addition, for example, the anaerobic treatment method is a method of decomposing organic matter into methane and carbon dioxide by anaerobic microorganisms. For example, treatment of wastewater containing high concentrations of organic matter such as human waste, sewage sludge, and food factory wastewater. Has been applied. In this method, generally, an organic substance or the like is digested in an anaerobic tank and the treated water is discharged. In addition, after the generated sludge is concentrated and dehydrated at the sludge treatment facility, the treated sludge is carried out, and the water recovered by dehydration is returned to the anaerobic tank as return water.

  Many wastewater treatment methods, including these methods, are effective in removing organic matter, but have a problem that nutrient salts such as nitrogen and phosphorus cannot be removed sufficiently. If these nutrient salts are released to public water bodies at a relatively high concentration, it will cause eutrophication of the discharge water areas, and the water environment will deteriorate, such as abnormal growth of algae and accompanying hypoxia. This problem is actually emerging and is a concern.

  On the other hand, a nitrification denitrification method is known as an advanced treatment technique for nitrogen in wastewater. The nitrification denitrification method converts ammonia nitrogen in wastewater to nitrate nitrogen under the aerobic conditions by the action of ammonia oxidizing microorganisms and nitrite oxidizing microorganisms, and then under anaerobic conditions, It is a method of converting nitrate nitrogen to nitrogen gas in a heterotrophic manner by working. Since both components can convert nitrogen components in wastewater into nitrogen gas, this method is effective when used alone, and for example, in combination with the above method, nitrogen can be removed in addition to organic substances. , Advanced wastewater treatment can be realized. In addition, for example, in the anaerobic treatment method, an increase in the nitrogen load in the anaerobic tank can be suppressed by performing the nitrification denitrification treatment before returning the return water.

The nitrification denitrification method is useful in that it can effectively remove nitrogen components in wastewater by biological treatment, but it requires aeration energy in the nitrification process, so the power cost is high, and the denitrification bacteria are heterotrophic bacteria Therefore, it is necessary to add a carbon source (ethanol, etc.) in the denitrification process, the nitrogen removal rate is slow, so the tank capacity needs to be increased, excessive sludge is generated, and sub-oxidation, which is a warming gas in the treatment process There are also problems such as the generation of nitrogen (N ₂ O).

  In recent years, a technique for removing nitrogen by anammox reaction (anammox; anaerobic ammonium oxidation) has attracted attention.

  The anammox reaction is a reaction in which ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas by an anammox microorganism that is anaerobic and autotrophic, through a metabolic pathway that is completely different from the conventional nitrification denitrification reaction. Since the nitrogen component in wastewater is ammoniacal nitrogen in many cases, this anammox reaction is used to remove the nitrogen component in wastewater as nitrogen gas.

  When nitrogen is removed by the anammox reaction, generally, a partial nitritation step of partially oxidizing ammonia nitrogen in wastewater to nitrite nitrogen and an anammox step of performing an anammox reaction are required. In the partial nitritation step, about half of the ammonia nitrogen is converted to nitrite nitrogen by the action of the ammonia oxidizing microorganism in the aerobic tank as in the case of the normal nitrification denitrification method. In the anammox process, ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas by the action of anammox microorganisms in an anaerobic tank.

Nitrogen removal technology by anammox reaction can reduce the aeration energy to about half compared with conventional methods such as nitrification denitrification method, so the power cost is low, no carbon source is required, and the nitrogen treatment speed is fast. It has the advantages of reducing capacity, generating less excess sludge, and generating less nitrous oxide (N ₂ O).

As a technique using the anammox reaction, for example, in Patent Document 1, in the waste liquid containing nitrite nitrogen and ammonia nitrogen, the nitrogen component in the waste liquid is removed as nitrogen gas while flowing the granules of anammox bacteria. In the present invention, a nonwoven fabric is used as a microorganism-adhering carrier. Patent Document 2 discloses a liquid containing autotrophic denitrifying microorganisms in a denitrification tank filled with nuclei of methane bacteria granules at a filling rate of 30 to 50% (volume) and filled with the nucleus. And the like, and the like, and the like, and the like, and the like, each of which includes a step of growing autotrophic denitrifying microorganisms on the surface of the nucleus and forming granules of the autotrophic denitrifying microorganisms. In Patent Document 3, as a method for maintaining the generation of nitrous acid necessary for anammox treatment for a long period of time, a fixed bed filter medium is obtained by fixing ammonia oxidizing bacteria to a carrier having a network structure or a pore structure, It describes a nitrite treatment method in which a fixed bed filter medium and wastewater containing ammonia nitrogen are brought into contact with each other to nitrite ammonia nitrogen. In addition, Patent Document 4 describes a mixed microorganism containing anammox bacteria discovered by the present inventors.
JP 2011-251255 A JP 2002-346593 A JP 2012-20262 Gazette JP 2013-192465 A

  Nitrogen removal treatment by anammox reaction has low power cost and high processing efficiency, but the growth speed of anammox microorganisms is slow, so it is difficult to keep anammox microorganisms in the treatment tank at high density in a short time. is there. For this reason, it takes time to start up the nitrogen removal treatment facility by the anammox reaction, which is an obstacle to the application of the nitrogen removal technology by the anammox reaction.

  Then, an object of this invention is to provide the means etc. which can hold | maintain anammox microorganisms in a processing tank in high density in a short time.

  The present inventors pay attention to the point that anammox microorganisms easily aggregate to form granule-like aggregates. By using a fixed bed carrier in which a large number of ring-shaped bodies are formed, anammox microorganisms can be obtained in a short time. It was newly found that it can be held at a high density in the treatment tank.

  Therefore, in the present invention, a wastewater treatment apparatus that performs wastewater treatment using anammox microorganisms, wherein a fixed bed carrier is disposed in a treatment tank, and the fixed bed carrier comprises an elongated core part and an outer periphery of the core part. Provided is a wastewater treatment apparatus or the like provided with a ring-shaped body that is formed by standing a large number over the entire surface, each of which is formed by bending fiber yarns and closing both ends thereof.

  According to the present invention, the anammox microorganism aggregates are caught so as to be entangled with the ring-shaped body of the fixed bed carrier, and the anammox microorganisms adhere and settle to the fixed bed carrier together with the aggregates. It can be held at high density in the tank. Thereby, the start-up time of the nitrogen removal processing equipment by an anammox reaction can be reduced significantly.

  In addition, since high accumulation of anammox microorganisms in the treatment tank is possible, highly efficient nitrogen removal by anammox reaction becomes possible. That is, for example, ammonia nitrogen in wastewater is partially oxidized to nitrite nitrogen in an aerobic tank, and after preparing primary treated water containing ammonia nitrogen and nitrite nitrogen, anammox microorganisms become dense. By supplying the primary treated water into the accumulated anaerobic tank, ammonia nitrogen and nitrite nitrogen are converted into nitrogen gas, and highly efficient nitrogen removal becomes possible.

  In addition, a thick biofilm of anammox microorganisms can be formed to wrap around the fixed bed carrier by attaching and fixing the anammox microorganisms to the fixed bed carrier at a high density. Thereby, stable treatment characteristics can be maintained in nitrogen removal by the anammox reaction.

  Therefore, for example, by setting the fixed bed carrier to hold anammox microorganisms and forming a biofilm having a diameter of 10 mm or more on the fixed bed carrier, the startup time of the nitrogen removal treatment facility by the anammox reaction can be greatly increased. In addition, a highly efficient and highly stable nitrogen removal process is possible.

  In addition, for example, an anammox microorganism and a nitrite microorganism may be held on the fixed bed carrier, and a biofilm having a diameter of 10 mm or more may be formed on the fixed bed carrier.

  In the case of this configuration, the anammox microorganisms can be held at a high density in the treatment tank in a short time as described above.

  In addition, by introducing anaerobic anammox microorganisms together with anaerobic anammox microorganisms into the treatment tank, the nitrite microorganisms adhere and settle on the fixed bed carrier as well, resulting in the core of the fixed bed carrier. On the part side, anaerobic conditions are mainly accumulated and a large amount of anammox microorganisms are mainly accumulated. On the outer peripheral side of the fixed bed carrier, an aerobic state is maintained to some extent and mainly a large amount of nitrite microorganisms are accumulated. A thick biofilm of both anammox microorganisms and nitrite microorganisms can be formed to wrap around the fixed bed carrier. As a result, an aerobic reaction (partial nitritation) and an anaerobic reaction (anammox reaction) can be performed in one treatment tank. Therefore, the nitrogen removal treatment equipment and process can be greatly simplified, and the construction cost, operation cost, and maintenance cost can be greatly reduced.

  In addition, under the aerobic condition, ammonia nitrogen is likely to be converted to nitrate nitrogen through nitrite nitrogen by oxidation reaction, whereas efficient removal of nitrogen by anammox reaction. It is necessary to control the oxidation reaction and suppress the conversion from ammonia nitrogen to nitrite nitrogen as much as possible, and to suppress the production of nitrate nitrogen. In contrast, in this configuration, nitrite nitrogen is generated from ammonia nitrogen by an aerobic reaction, and then the nitrite nitrogen is quickly used in the anammox reaction. The oxidation reaction to nitrogen can be suppressed, and the production of nitrate nitrogen can be suppressed. Therefore, high efficiency and stabilization of nitrogen removal by the anammox reaction can be achieved.

  According to the present invention, anammox microorganisms can be held in the treatment tank at high density in a short time.

<About the wastewater treatment apparatus according to the present invention>
The present invention is a wastewater treatment apparatus for treating wastewater using anammox microorganisms, wherein a fixed bed carrier is disposed in a treatment tank, and the fixed bed carrier is disposed on an elongated core part and the entire outer periphery of the core part. A plurality of waste water treatment devices each including a ring-shaped body formed by bending a fiber yarn and closing both ends thereof are provided. Examples thereof will be described below with reference to FIGS. 1, 2A, and 2B. Note that the present invention is not limited to this embodiment.

  FIG. 1 is a schematic configuration diagram illustrating an example of a wastewater treatment apparatus according to the present invention, FIG. 2A is a schematic top view of an appearance illustrating an example of a fixed bed carrier according to the present invention, and FIG. 2B is a schematic perspective view of the same appearance. .

  The wastewater treatment apparatus A in FIG. 1 supplies a treatment tank 1, a plurality of fixed bed carriers 2, 2, and 2 arranged in a substantially vertical direction in the treatment tank 1, and treated water W1 into the treatment tank 1. To-be-treated water supply means 3, treated water discharge means 4 for discharging treated water W2 out of treatment tank 1, stirring means 5 for stirring the inside of treatment tank 1, and generated nitrogen gas outside treatment tank 1. And a gas discharging means 6 for discharging. A biofilm 29 is formed around the fixed bed carrier 2 arranged in the treatment tank 1. In the treatment tank 1, the treated water W1 is stored up to the level of the water level W11.

  2A or 2B is formed by standing a large number of elongated core portions 21 and the entire outer periphery of the core portion 21, each of which is formed by bending the fiber yarn 221 and closing both ends thereof. A ring-shaped body 22 is provided. A biofilm 29 is formed around the fixed bed carrier 2.

  The treatment tank 1 is a part that stores the treated water W1 supplied by the treated water supply means 3 for a certain period of time and performs a nitrogen removal process. The treatment tank 1 can be appropriately sized and configured according to the purpose and is not particularly limited. For example, when the nitrogen removal treatment is performed using an anammox reaction, the anammox microorganism is absolutely anaerobic. It is preferable to create conditions that have as few opportunities to contact sealed air as possible.

  The fixed bed carrier 2 arranged in the treatment tank 1 is a part for adhering / fixing and holding microorganisms used for nitrogen removal treatment. In the present invention, the fixed bed carrier 2 includes an elongated core portion 21 and a large number of ring-shaped bodies 22 erected over the entire outer periphery of the core portion.

  The means for forming the fixed bed carrier 2 is not particularly limited. For example, the core portion 21 is formed in a substantially cylindrical shape by twisting the core material 21 after knitting the fiber yarn 221 so that a large number of ring-shaped bodies 22 are formed on an elongated cloth-like member. In addition, a shape in which a large number of ring-shaped bodies 22 are erected over the entire outer periphery thereof may be formed. Further, the ring-like body 22 and the portion corresponding to the core portion 21 may be formed by knitting the fiber yarn 221. In addition, the ring-shaped body 22 is formed in advance, and the shape of the fixed bed carrier according to the present invention is formed by attaching and fixing the ring-shaped body 22 over the entire outer surface of the rod-shaped or string-shaped member. Also good.

  The core portion 21 is a base material portion on which a large number of ring-shaped bodies 22 are erected. For example, it has a form such as a substantially bar shape or a substantially string shape.

  The ring-shaped body 22 is a portion having a substantially ring-shaped (substantially looped) form, and a large number of the ring-shaped bodies 22 are provided over the entire outer periphery (side wall surface) of the core portion 21.

  Each ring-shaped body 22 is formed in a substantially ring shape by bending the fiber yarn 221 and closing both ends thereof. The portion of the fiber yarn 221 is a substantial portion of the ring-shaped body 22, and the ring hole portion surrounded by the fiber yarn 221 is a hollow circulatable portion. By forming each ring-shaped body 22 from the fiber yarns 221 and forming a substantially ring shape, the anammox microorganisms are caught so as to be entangled, and the anammox microorganisms adhere to and adhere to the fixed bed carrier together with the aggregates. Therefore, anammox microorganisms can be held in the treatment tank at high density in a short time.

  The size of the formed ring-shaped body 22 is not particularly limited, but is large enough to catch the aggregates of anammox microorganisms, that is, the maximum width d1 of the ring-shaped body 22 is 5 to 20 mm, and the maximum length d2 is 5 to 30 mm. More preferably, the maximum width d1 of the ring-shaped body 22 is 6 to 15 mm, and the maximum length d2 is 8 to 25 mm, and the maximum width d1 of the ring-shaped body 22 is 8 to 12 mm and the maximum length. Most preferably, the length d2 is 10 to 20 mm. Here, the maximum lateral width d1 is the maximum distance between opposing fibers when the fiber yarn 221 is bent to form the ring-shaped body 22, and the maximum length is the maximum distance between the fibers 221, which are bent. It is the length from the root portion (core surface) when formed to the tip portion (portion farthest from the core portion).

  Each annular body 22 may be formed as a bundle of a plurality of fiber yarns 221, 221, 221. For example, by forming one ring-shaped body 22 as a bundle of 2 to 10 fiber yarns, the aggregates of anammox microorganisms are efficiently hooked by the ring-shaped body of the fixed bed carrier, and the anammox microorganisms together with the aggregates are fixed to the fixed bed. Since it can adhere and fix to the carrier, anammox microorganisms can be held in the treatment tank at a high density in a shorter time.

  The material of the fiber yarn 221 forming the ring-shaped body 22 can be widely used, and is not limited to a narrow one.For example, anammox microorganisms are easily attached and fixed, and in the treatment tank 1 or the water to be treated W1. It is preferably a highly durable member that can maintain carrier performance even when installed for a long time. As a material of the fiber yarn 221, for example, synthetic fiber, natural fiber, inorganic fiber, metal fiber, or a combination of them can be used. Examples of the synthetic fiber include polyester fiber, nylon fiber, acrylic fiber, polyolefin fiber, polyvinyl alcohol fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, polyurethane fiber, polyacetal fiber, polyfluoroethylene fiber, and phenol fiber. . Examples of natural fibers include cotton, silk, flax, jute and the like. Examples of the inorganic fibers include carbon fibers and glass fibers. Examples of metal fibers include iron fibers and copper fibers.

  The treated water supply means 3 is a part that supplies the treated water W1 to the treatment tank 1 (see X1 in FIG. 1). The method for supplying the water to be treated W1 to the treatment tank 1 can be widely used, and is not particularly limited.

  The treated water discharge means 4 is a part that discharges the treated water W2 to the outside of the treated tank 1 after performing a nitrogen removing process in the treated tank 1 (see reference numeral X2 in FIG. 1). The method for discharging the treated water W2 to the outside of the treatment tank 1 can be widely employed, and is not particularly limited.

  The stirring means 5 is a part for stirring the water to be treated W1 stored in the treatment tank. Agitation of the anammox microorganisms can be moved to the vicinity of the ring-shaped body 22 of the fixed bed carrier by stirring the inside of the treatment tank 1 with the stirring means 5, and the aggregate is caught on the ring-shaped body 22 and adhered and fixed. Can be promoted. In addition, by stirring the inside of the treatment tank 1 with the stirring means 5, the contact between the microorganisms held on the fixed bed carrier 2 and the water to be treated W1 can be increased, so that the treatment efficiency can be improved. Regarding the stirring method, known techniques can be widely adopted and are not particularly limited.

  The gas discharge means 6 is a part that discharges nitrogen gas generated by the nitrogen removal process to the outside of the processing tank 1 (see symbol X3 in FIG. 1). The method for discharging nitrogen gas and the like out of the processing tank 1 can be widely employed publicly known technology and is not particularly limited.

  For example, when wastewater treatment is performed using anammox microorganisms, first, sludge containing anammox microorganisms (anammox sludge) is introduced into the treatment tank 1 of the wastewater treatment apparatus A, and the anammox microorganisms are adhered to and fixed on the fixed bed carrier 2. . For example, anammox microorganisms can be attached and fixed in the treatment tank 1 by introducing anammox sludge into the treatment tank 1 as seed sludge and continuously supplying the raw material for a predetermined period.

  As an anammox sludge, a well-known thing can be employ | adopted widely and it does not specifically limit, For example, you may employ | adopt the mixed microorganisms of patent document 4. The input amount of anammox sludge can be determined appropriately depending on conditions, etc., for example, 10 to 1,000 mg of anammox sludge is suitable in terms of SS amount per liter of nitrogen removal tank, and more preferably 50 to 500 mg. 100-400 mg is most preferred.

  For example, when anammox microorganisms are introduced into the treatment tank 1 of the wastewater treatment apparatus A, the anammox microorganisms adhere and settle to the fixed bed carrier 2 together with the aggregates, and the anammox microorganisms are held in the treatment tank at a high density in a short time. be able to. When anammox microorganisms adhere and settle to the fixed bed carrier 2 at a high density, a thick biofilm 29 of the anammox microorganisms is formed so as to wrap the fixed bed carrier 2.

  By forming the thick biofilm 29 around the fixed bed carrier 2, stable treatment characteristics can be maintained in nitrogen removal by the anammox reaction. The biofilm 29, for example, preferably has a diameter (the maximum diameter of a horizontal cross section with respect to the longitudinal direction of the fixed bed carrier 2 installed in a substantially vertical direction) of 10 mm or more, more preferably 20 mm or more. A thickness of 30 mm or more is most suitable. The formed biofilm 29 has a diameter of approximately 150 mm or less.

  To-be-treated water W1 (nitrogen removal raw material, etc.) to which this device A is applied includes water containing at least nitrogen, for example, wastewater such as domestic wastewater, human waste, industrial wastewater, agricultural / livestock wastewater, etc. In addition, water after wastewater treatment, for example, water after activated sludge treatment (including effluent water), water after anaerobic treatment (including effluent water, return water, etc.), water after pretreatment, eg, part Water after nitritation treatment is widely included.

  When wastewater treatment is performed using anammox microorganisms, it is preferable that ammonia nitrogen and nitrite nitrogen are contained and the ratio thereof is in the range of 1: 1 to 1: 1.5. Therefore, for example, as a pretreatment, the raw material may be aerated and a part of ammonia nitrogen may be converted into nitrite nitrogen by the action of ammonia oxidizing bacteria before being supplied to the treatment tank 1.

  On the other hand, for example, when wastewater treatment is performed using anammox microorganisms and nitrite microorganisms, first, sludge containing anammox microorganisms (anammox sludge) and sludge containing nitrite microorganisms in the treatment tank 1 of this wastewater treatment apparatus A ( Nitrite sludge) is introduced, and anammox microorganisms and nitrite microorganisms are adhered to and fixed on the fixed bed carrier 2. For example, by introducing anammox sludge and nitrite sludge as seed sludge into the treatment tank 1 and continuously supplying raw materials for a predetermined period, as described above, mainly the anammox microorganisms on the core 21 side of the fixed bed carrier 2 The nitrite microorganisms can be mainly retained at a high density on the outer peripheral side of the fixed bed carrier 2. In addition, a thick biofilm 29 of both microorganisms is formed so as to wrap the fixed bed carrier 2. Thereby, an aerobic reaction (partial nitritation) and an anaerobic reaction (anammox reaction) can be performed in one processing tank.

  The biofilm 29 made of anammox microorganisms and nitrite microorganisms preferably has a diameter (maximum horizontal cross section with respect to the longitudinal direction of the fixed bed carrier 2 installed in a substantially vertical direction) of 10 mm or more, and a diameter of 20 mm. The above is more preferable, and a diameter of 30 mm or more is most preferable. The formed biofilm 29 has a diameter of approximately 150 mm or less.

  When wastewater treatment is performed using anammox microorganisms and nitrite microorganisms, aeration means (not shown) for the nitrite microorganisms may be disposed in the treatment tank 1 separately. Even when the water to be treated W1 is aerated, a fixed area of anammox microorganisms is mainly formed inside the thick biofilm 29, and the anaerobic condition is generally maintained in that area.

<Wastewater treatment method using Anammox microorganisms>
According to the present invention, a fixed bed carrier in which a large number of ring-shaped bodies formed by bending fiber yarns and closing both ends thereof are provided over the entire outer periphery of an elongated core portion is disposed in a treatment tank, and the fixing is performed. It includes all wastewater treatment methods in which anammox microorganisms are retained on a floor carrier and wastewater is treated in the treatment tank.

  As described above, by using a fixed bed carrier in which a large number of ring-shaped bodies are erected over the entire outer periphery of the elongated core, the aggregates of anammox microorganisms are caught so as to be entangled with the ring-shaped body of the fixed bed carrier. Since the anammox microorganisms adhere and settle to the fixed bed carrier together with the aggregates, the anammox microorganisms can be held in the treatment tank at a high density in a short time. Thereby, the start-up time of the nitrogen removal processing equipment by an anammox reaction can be reduced significantly.

  First, for example, anammox microorganisms are held on the fixed bed carrier in the treatment tank by a process of adding anammox sludge as seed sludge to the treatment tank. For example, when the biofilm is formed so as to wrap the fixed bed carrier and the attachment / fixation of anammox microorganisms is confirmed by the nitrogen removal rate or the like, full-scale operation for nitrogen removal is started.

  Next, for example, water to be treated (raw material for nitrogen removal treatment) is introduced into the treatment tank, and the nitrogen removal treatment is started. In the nitrogen removal treatment by this method, continuous treatment is possible.

  In addition, for example, as a pretreatment, for example, the raw material is aerated before the treated water is put into the treatment tank, and a part of ammonia nitrogen is converted to nitrite nitrogen by the action of ammonia oxidizing bacteria. It may be.

<Wastewater treatment method using anammox microorganisms and nitrite microorganisms>
According to the present invention, a fixed bed carrier in which a large number of ring-shaped bodies formed by bending fiber yarns and closing both ends thereof are provided over the entire outer periphery of an elongated core portion is disposed in a treatment tank, and the fixing is performed. All of the wastewater treatment methods in which anammox microorganisms and nitrite microorganisms are held on a floor carrier and wastewater is treated in the treatment tank are included.

  As described above, anaerobic anammox microorganisms and aerobic nitrite microorganisms are introduced into the treatment tank, so that anammox microorganisms are mainly placed on the core side of the fixed bed carrier, and mainly on the outer peripheral side of the fixed bed carrier. Nitrite microorganisms can be retained at high density, and a thick biofilm of both microorganisms can be formed to wrap around the fixed bed carrier. Thereby, a nitritation process and a nitrogen removal process can be performed in one processing tank.

  First, for example, by introducing sludge containing anammox microorganisms (anammox sludge) and sludge containing nitrite microorganisms (nitrite sludge) into the treatment tank, anammox microorganisms and nitrite are added to the fixed bed carrier in the treatment tank. Keep microorganisms. Then, for example, when a biofilm is formed so as to wrap the fixed bed carrier and the attachment / fixation of anammox microorganisms and nitrite microorganisms is confirmed by the nitrogen removal rate, etc., full-scale operation for nitrogen removal is started. .

  Next, for example, water to be treated (raw material for nitrogen removal treatment) is introduced into the treatment tank, and the nitrogen removal treatment is started. In the nitrogen removal treatment by this method, continuous treatment is possible. In this method, there is an advantage that the process of converting a part of ammonia nitrogen into nitrite nitrogen can be omitted, and the treatment tank can be made into one tank.

  In Example 1, a start-up experiment of a wastewater treatment reactor by an anammox reaction was performed using the fixed bed carrier according to the present invention.

  As a fixed floor carrier according to the present invention, a fiber yarn made of polyvinylidene chloride is knitted on one surface of an elongated cloth-like member so that a large number of ring-shaped bodies are formed in a state where both ends thereof are closed. After finding, the core material was twisted to form the core portion in a substantially rod shape (substantially cylindrical shape), and a large number of ring-shaped bodies were erected over the entire outer periphery. A polyester non-woven fabric was used as a control fixed bed carrier.

A fixed bed carrier was placed in a culture tank of a 2 L jar fermenter having the same configuration as in FIG. 1, and the raw materials were continuously charged so as to be 6 L / day. The liquid in the jar fermenter was discharged by overflow. The composition of the raw material used was as follows. Sodium nitrite (NaNo ₂ ) 860 mg / L, ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) 875 mg / L, potassium bicarbonate (KHCO ₃ ) 500 mg / L, potassium dihydrogen phosphate (KH ₂ PO ₄ ) 27 mg / L Magnesium sulfate (MgSO ₄ · 7H ₂ O) 300 mg / L, calcium chloride (CaCl ₂ · 2H ₂ O) 180 mg / L, trace element solution I 1 mg / L, trace element solution II 1 mL / L. The composition of the trace element solution I was 5 g / L ethylenediaminetetraacetic acid (EDTA) and 5 g / L iron sulfate (FeSO ₄ ). The composition of the trace element solution II is ethylenediaminetetraacetic acid (EDTA) 15g / L, zinc sulfate heptahydrate _{(ZnSO 4 · 7H 2 O)} 0.43g / L, cobalt chloride hexahydrate (CoCl ₂ · 6H ₂ O ) 0.24 g / L, manganese chloride tetrahydrate _{(MnCl 2 · 4H 2 O)} 0.99g / L, copper sulfate pentahydrate _{(CuSO 4 · 5H 2 O)} 0.25g / L, sodium molybdate dihydrate (NaMoO ₄・ 2H ₂ O) 0.22g / L, nickel chloride hexahydrate (NiCl ₂・ 6H ₂ O) 0.19g / L, sodium selenate decahydrate (NaSeO ₄・ 10H ₂ O) 0.21g / L, boric acid (H ₃ BO ₄ ) 0.014 g / L. The temperature in the culture tank was adjusted to 35 ° C.

  About 200 mL of anammox sludge (SS concentration 2,000 mg / L) used in Patent Document 4 as seed sludge is added to the culture tank, and then the influent supplied to the culture tank and the effluent overflowed from the culture tank Using ion exchange chromatography, the attached conductivity detector measured the concentration of ammonium salt, nitrite and nitrate, and the nitrogen removal rate was automatically calculated based on the data and raw material supply. .

The results are shown in Figure 3. FIG. 3 is a graph showing the nitrogen removal rate when the fixed bed carrier according to the present invention is used. The horizontal axis in Fig. 3 represents the number of days that have elapsed since the introduction of anammox sludge (unit: days), and the vertical axis represents the nitrogen removal rate (unit: kg / m ³ / day). In the graph, the broken line of “ring-shaped carrier” represents the result when the fixed bed carrier according to the present invention is used, and the broken line of “nonwoven fabric carrier” represents the result when the non-woven fabric fixed bed carrier is used.

As shown in FIG. 3, when a commonly used non-woven fabric fixed bed carrier was used, the nitrogen removal rate increased gently, and it took about 3 months to start up the nitrogen removal treatment apparatus. When the fixed bed carrier according to was used, the nitrogen removal rate reached a high level of about 0.6 kg / m ³ / day in about 20 days, and the start-up of the nitrogen removal treatment apparatus could be completed within one month. As a result of visual observation, it was confirmed that a biofilm of about 40 mm was formed within about one month.

  As a result, the fixed bed carrier according to the present invention can hold the anammox microorganisms in the treatment tank at a high density in a short time, and the startup time of the nitrogen removal treatment equipment by the anammox reaction is thereby reduced. It shows that it can be greatly shortened.

  In Example 2, it was examined whether ammonia nitrogen could be removed without supplying nitrite nitrogen by fixing anammox microorganisms and nitrite microorganisms to the fixed bed carrier according to the present invention.

A culture tank of a 5 L jar fermenter having the same configuration as in FIG. 1 is filled with a fixed bed carrier in which a large number of annular bodies are formed on the outer periphery of the core material, as in Example 1, and the raw material is 30 L / It was thrown continuously to be a day. The liquid in the jar fermenter was discharged by overflow. The composition of the raw material used was as follows. As ammonium nitrogen, ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) 875 mg / L, potassium bicarbonate (KHCO ₃ ) 500 mg / L, potassium dihydrogen phosphate (KH ₂ PO ₄ ) 27 mg / L, magnesium sulfate (MgSO ₄ 7H ₂ O) 300 mg / L, calcium chloride (CaCl ₂ · 2H ₂ O) 180 mg / L, trace element solution I 1 mg / L, trace element solution II 1 mL / L. The composition of the trace element solution I was 5 g / L ethylenediaminetetraacetic acid (EDTA) and 5 g / L iron sulfate (FeSO ₄ ). The composition of the trace element solution II is ethylenediaminetetraacetic acid (EDTA) 15g / L, zinc sulfate heptahydrate _{(ZnSO 4 · 7H 2 O)} 0.43g / L, cobalt chloride hexahydrate (CoCl ₂ · 6H ₂ O ) 0.24 g / L, manganese chloride tetrahydrate _{(MnCl 2 · 4H 2 O)} 0.99g / L, copper sulfate pentahydrate _{(CuSO 4 · 5H 2 O)} 0.25g / L, sodium molybdate dihydrate (NaMoO ₄・ 2H ₂ O) 0.22g / L, nickel chloride hexahydrate (NiCl ₂・ 6H ₂ O) 0.19g / L, sodium selenate decahydrate (NaSeO ₄・ 10H ₂ O) 0.21g / L, boric acid (H ₃ BO ₄ ) 0.014 g / L. The temperature in the culture tank was adjusted to 35 ° C.

  The anammox sludge (SS concentration 2,000mg / L) and nitrite sludge (sludge containing nitrite microorganisms) used in Patent Document 4 are mixed, and 20% each is added to the culture tank as seed sludge. For the influent supplied to the tank and the effluent overflowing from the culture tank, the concentration of ammonium salt, nitrite, and nitrate is measured using the attached conductivity detector using ion exchange chromatography. At the same time, the nitrogen removal rate was automatically calculated based on the data and the raw material supply amount.

The results are shown in FIG. FIG. 4 is a graph showing the nitrogen removal rate when anammox microorganisms and nitrite microorganisms are fixed on the fixed bed carrier according to the present invention. The horizontal axis in Fig. 4 represents the number of days elapsed since each sludge was added (unit: days), the vertical axis on the left side is the nitrogen concentration (unit: mg / L), and the vertical axis on the right side is the nitrogen removal rate ( (Unit: kg / m ³ / day). Nitrogen removal rate polygonal line in each course date "nitrogen removal rate" in the graph, the concentration of ammonium nitrogen polygonal line that has flowed into the culture tank at each elapsed date of "inflow NH _4", "outflow NH ₄ the polygonal line the concentration of ammonium nitrogen flowing out to the outside of the culture vessel in each elapsed date ", a line concentration of nitrite nitrogen flowing out into the culture tank at each elapsed date of" outflow N0 ₂ "," outflow NO _The “ ₃ ” line represents the concentration of nitrate nitrogen flowing out of the culture tank on each elapsed day.

As shown in Fig. 4, the removal of nitrogen was confirmed immediately after the start of the experiment, and the nitrogen removal rate gradually increased with the passage of days, and after about 3 months from the introduction of the seed sludge, the nitrogen removal rate was about 1.6. kg / m ³ / day reached. This value is almost the same as the normal case where nitritation treatment and nitrogen removal treatment are performed separately in two tanks.

  Therefore, this result is obtained by using the fixed bed carrier according to the present invention to hold the anammox microorganism and the nitrite microorganism on the fixed bed carrier, and thereby an aerobic reaction (partial nitritation) and an anaerobic reaction (anammox). It shows that (reaction) can be performed in one processing tank.

  As described above, the fixed bed carrier according to the present invention has a high density of anammox microorganisms in the treatment tank in a short time compared with the nonwoven fabric carrier that has been widely used as a conventional fixed bed carrier in the nitrogen removal technology by the anammox reaction. Can be held. Thereby, the start-up time of the nitrogen removal processing equipment by an anammox reaction can be reduced significantly. In addition, since the anammox microorganisms can be held in the treatment tank at a high density according to the present invention, it is possible to improve the efficiency and stability of the nitrogen removal treatment by the anammox reaction.

  In addition, by adopting the fixed bed carrier according to the present invention, anammox microorganisms can be held in the treatment tank at a high density in a short period of time. For example, anammox microorganisms and nitrite microorganisms are introduced into the treatment tank. In this case, both microorganisms can adhere to and settle on the fixed bed carrier, which allows the aerobic reaction (partial nitritation) and the anaerobic reaction (anammox reaction) to be performed in one treatment tank. It becomes possible. Therefore, the nitrogen removal treatment equipment and process can be greatly simplified, and the construction cost, operation cost, and maintenance cost can be greatly reduced.

The structure schematic diagram which shows the example of the wastewater treatment apparatus which concerns on this invention. The external appearance top view schematic diagram which shows the example of the fixed bed support | carrier which concerns on this invention. The external appearance schematic perspective view which shows the example of the fixed bed carrier based on this invention. The graph which shows the nitrogen removal rate at the time of using the fixed bed support | carrier which concerns on this invention. The graph which shows the nitrogen removal rate at the time of making an anammox microorganism and a nitritation microorganism settle on the fixed bed support | carrier which concerns on this invention.

1 Treatment tank
2 Fixed bed carrier
21 core
22 Ring-shaped body
221 Fiber yarn
29 Biofilm
3 To-be-treated water supply means
4 Processed water discharge means
5 Stirring means
6 Gas discharge means
A Wastewater treatment equipment
W1 treated water
W2 treated water

Claims (8)

A wastewater treatment apparatus for treating wastewater using anammox microorganisms,
A fixed bed carrier is arranged in the treatment tank,
The fixed bed carrier includes a long and thin core part, and a ring-shaped body formed by bending a fiber yarn and closing both ends thereof, each being erected over the entire outer periphery of the core part. Waste water treatment equipment.   2. The waste water treatment apparatus according to claim 1, wherein each ring-shaped body is formed as a bundle of a plurality of fiber yarns.   3. The wastewater treatment apparatus according to claim 1, wherein the maximum width of the ring-shaped body is 5 to 20 mm. Anammox microorganisms are retained on the fixed bed carrier,
The wastewater treatment apparatus according to any one of claims 1 to 3, wherein a biofilm having a diameter of 10 mm or more is formed on the fixed bed carrier. Anammox microorganisms and nitrite microorganisms are retained on the fixed bed carrier,
The wastewater treatment apparatus according to any one of claims 1 to 3, wherein a biofilm having a diameter of 10 mm or more is formed on the fixed bed carrier.   A fixed bed carrier in which a large number of ring-shaped bodies formed by bending fiber yarns and closing both ends thereof are provided over the entire outer periphery of the elongated core portion is disposed in a treatment tank, and the fixed bed carrier is anammox. A wastewater treatment method for retaining microorganisms and treating wastewater in the treatment tank.   A fixed bed carrier in which a large number of ring-shaped bodies formed by bending fiber yarns and closing both ends thereof are provided over the entire outer periphery of the elongated core portion is disposed in a treatment tank, and the fixed bed carrier is anammox. A wastewater treatment method for retaining microorganisms and nitrite microorganisms and treating wastewater in the treatment tank.   8. The wastewater treatment method according to claim 7, wherein the nitritation treatment and the nitrogen removal treatment are performed in one treatment tank.

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