Microorganism carrier and method for producing microorganism carrier

Abstract

To provide a microorganism carrier for use in wastewater treatment and a method for manufacturing the microorganism carrier, which can suppress the reduction of the carried microorganisms and can be used for a long period of time.SOLUTION: A microorganism carrier of the present disclosure has a first metal film containing at least one of zinc, manganese, cobalt, and copper on a substrate, and microorganisms containing at least one of ammonia oxidizing bacteria and anammox bacteria are supported on the first metal film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a microbial carrier used for wastewater treatment and a method for manufacturing the microbial carrier.

Background Art

[0002] Conventionally, in wastewater treatment facilities for industrial wastewater, domestic wastewater, etc., wastewater has been mainly purified using activated sludge. Activated sludge contains microorganisms that decompose ammonia and the like.

[0003] FIG. 5 is a diagram showing an example of a wastewater treatment process using conventional activated sludge. Note that FIG. 5 describes the process that is the main part related to the present disclosure in the wastewater treatment process, and other accompanying processes are omitted.

[0004] As shown in FIG. 5, in a wastewater treatment process 150 using conventional activated sludge, wastewater 161 is sent to a treatment tank 160 (this treatment tank 160 is also called an aeration tank), and the ammonia contained therein is decomposed. Then, it is sent to a sedimentation tank 170 and separated from sludge 172, and the supernatant treated water 171 is discharged as purified water.

[0005] Part of the sludge 172 sedimented in the sedimentation tank 170 is recovered as activated sludge containing microorganisms and sent to the treatment tank 160. The sludge 172 that is not recovered is treated as excess sludge.

[0006] In the treatment tank 160, oxygen is supplied to the microorganisms contained in the activated sludge, and the microorganisms use the oxygen to decompose ammonia. For example, ammonia is nitrified to nitric acid by nitrifying bacteria, and nitric acid is denitrified to nitrogen gas by denitrifying bacteria.

[0007] The oxygen required by the microorganisms for nitrification is supplied from the oxygen supply device 165 into the wastewater 161 through the pipe 166. The supplied oxygen may be the oxygen in the air. Usually, the gas supplied into the wastewater 161 is air. And a blower for sending air into the oxygen supply device 165 is used. It is preferable that the wastewater 161 is stirred so that the microorganisms and the sludge 162 are in a mixed state, enabling the microorganisms to effectively contact oxygen and ammonia.

[0008] As described above, in order to effectively utilize the microorganisms contained in the activated sludge, a large amount of air and electricity are required. Also, in the conventional wastewater treatment process using activated sludge, the treatment of excess sludge is also a problem. For example, as the microorganisms contained in the activated sludge grow, the amount of excess sludge also increases. The increased excess sludge cannot be fully utilized and will be discarded, which contributes to environmental problems.

[0009] Therefore, a method has been proposed in which effective microorganisms contained in the activated sludge are supported on a carrier, and ammonia is decomposed using the carrier carrying these microorganisms (referred to as a microbial carrier) (for example, Patent Document 1). According to this method, it is possible to suppress air and electricity compared to the conventional wastewater treatment process using activated sludge, and it is also possible to reduce excess sludge.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] However, conventional microbial carriers have a problem in that the microorganisms supported thereon decrease over the period of use, making long-term use difficult.

[0012] The present disclosure has been made in view of the above circumstances, and a main object thereof is to provide a microorganism carrier and a method for manufacturing the microorganism carrier that suppress a decrease in the carried microorganisms and enable long-term use.

Means for Solving the Problems

[0013] The microorganism carrier of the present disclosure has a first metal film containing at least one of zinc, manganese, cobalt, or copper on a base material, and a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria is carried on the first metal film.

[0014] In the microorganism carrier of the present disclosure, the base material may be composed of a material having conductivity.

[0015] In the microorganism carrier of the present disclosure, the base material may be any one of porous carbon, a metal mesh, a metal substrate having an uneven structure, or a metal substrate having through holes.

[0016] The microorganism carrier of the present disclosure may have a second metal film between the base material and the first metal film.

[0017] In the microorganism carrier of the present disclosure, the second metal film may contain nickel.

[0018] In the microorganism carrier of the present disclosure, the base material may be any one of a hydrophilic polymer gel, a nonwoven fabric, plastic mesh fibers, porous plastic, or porous ceramic.

[0019] The method for manufacturing the microorganism carrier of the present disclosure includes a first metal film forming step in which a first metal film containing at least one of zinc, manganese, cobalt, or copper is formed on a base material by an electrolytic plating method, and a microorganism carrying step in which a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria is carried on the first metal film.

[0020] In the method for manufacturing the microbial carrier of the present disclosure, the base material may be any one of porous carbon, a metal mesh, a metal substrate having an uneven structure, or a metal substrate having through holes.

[0021] The method for manufacturing the microbial carrier of the present disclosure may include a second metal film forming step in which a second metal film containing nickel is formed on the base material by electroless plating, and a first metal film containing at least one of zinc, manganese, cobalt, or copper is formed on the second metal film by electrolytic plating. And a microbial loading step of loading a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria on the first metal film.

[0022] In the method for manufacturing the microbial carrier of the present disclosure, the base material may be any one of a hydrophilic polymer gel, a non-woven fabric, plastic mesh fibers, porous plastic, or porous ceramic.

Effects of the Invention

[0023] According to the present disclosure, it is possible to provide a microbial carrier and a method for manufacturing the microbial carrier that suppress a decrease in the loaded microorganisms and enable long-term use.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different modes and is not construed as being limited to the description of the embodiments exemplified below. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but this is merely an example and does not limit the interpretation of the present disclosure. Further, in this specification and each figure, elements similar to those described above with respect to the previously shown figures may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0026] In this specification, when expressing the mode of arranging one member on another member, if simply denoted as "on" or "under", unless otherwise specified, it includes both the case of arranging another member directly above or directly below so as to be in contact with a certain member, and the case of arranging another member above or below a certain member with yet another member interposed therebetween. Also, in this specification, when expressing the mode of arranging one member on the surface of another member, if simply denoted as "on the surface", unless otherwise specified, it includes both the case of arranging another member directly above or directly below so as to be in contact with a certain member, and the case of arranging another member above or below a certain member with yet another member interposed therebetween.

[0027] Hereinafter, the microbial carrier according to the present disclosure and the method for manufacturing the microbial carrier will be described in detail.

[0028] <Microbial carrier> The microbial carrier of the present disclosure is used for wastewater treatment. More specifically, the microbial carrier of the present disclosure is immersed in wastewater and used for the treatment of decomposing ammonia contained in the wastewater. FIG. 1 is a schematic cross-sectional view showing a configuration example of the microbial carrier of the present disclosure. Also, FIG. 2 is a schematic cross-sectional view showing another configuration example of the microbial carrier of the present disclosure.

[0029] As shown in FIG. 1, the microbial carrier 10 has a first metal film 12 on a base material 11, and microorganisms 13 are supported on the first metal film 12. In the microbial carrier 10, the form of supporting the microorganisms 13 is a form in which the microorganisms 13 are attached and fixed on the first metal film 12.

[0030] Note that the microbial carrier 10 shown in FIG. 1 has a first metal film 12 on both sides of the base material 11, and microorganisms 13 are respectively supported on each first metal film 12. However, the microbial carrier of the present disclosure is not limited to this.

[0031] For example, the microbial carrier of the present disclosure may have a first metal film 12 only on one side of the base material 11, and the microorganisms 13 may be supported on the first metal film 12. Further, the microbial carrier of the present disclosure may have a first metal film 12 only on one side of the base material 11, the microorganisms 13 may be supported on the first metal film 12, and the microorganisms 13 may also be supported on the other side (the side without the first metal film 12) of the base material 11.

[0032] Here, if it is in a form like the microbial carrier 10 shown in FIG. 1, having a first metal film 12 on both sides of the base material 11 and having microorganisms 13 supported on each first metal film 12 respectively, more microorganisms 13 can be supported. Furthermore, by including a metal that promotes the growth of the microorganisms 13 in the first metal film 12, the growth of the microorganisms 13 supported on both sides of the base material 11 can be promoted more.

[0033] The first metal film 12 contains at least one of zinc, manganese, cobalt, or copper as a metal. The microorganisms 13 have the ability to decompose ammonia. More specifically, the microorganisms 13 contain at least one of ammonia-oxidizing bacteria or anammox bacteria.

[0034] Ammonia-oxidizing bacteria and anammox bacteria are known to grow in an environment where zinc, manganese, cobalt, or copper is present. Among them, the presence of zinc is preferred. Therefore, if at least one of zinc, manganese, cobalt, or copper is included in the layer constituting the surface on which ammonia-oxidizing bacteria or anammox bacteria, or both, are supported (the first metal film 12 in the microbial carrier 10 shown in FIG. 1), ammonia-oxidizing bacteria or anammox bacteria, or both, will be more likely to grow. Therefore, the microbial carrier 10 having the above configuration suppresses the decrease in the supported microorganisms and enables long-term use.

[0035] In addition, when heavy metals such as zinc are added to the liquid in wastewater treatment, if the liquid containing the added zinc or the like flows out, it may cause pollution. However, as in the present disclosure, if zinc or the like is immobilized as a metal film on the microbial carrier, the above problem can be solved.

[0036] The base material 11 of the microbial carrier 10 shown in FIG. 1 is preferably composed of a conductive material. When the base material 11 is composed of a material having conductivity, an electrolytic plating method can be preferably used as a method for forming the first metal film 12 on the base material 11.

[0037] On the other hand, the microbial carrier 20 shown in FIG. 2 has a second metal film 22 on the base material 21, has a first metal film 12 on the second metal film 22, and has microorganisms 13 supported on the first metal film 12. The form of supporting the microorganisms 13 in the microbial carrier 20 is a form in which the microorganisms 13 are attached and fixed on the first metal film 12. That is, the configuration of the microbial carrier 20 shown in FIG. 2 corresponds to a configuration having a second metal film 22 between the base material 11 and the first metal film 12 of the microbial carrier 10 shown in FIG. 1.

[0038] Note that the microbial carrier 20 shown in FIG. 2 has a second metal film 22 on each of the two sides of the base material 21, a first metal film 12 on each of the second metal films 22, and microorganisms 13 are carried on each of the first metal films 12. However, the microbial carrier of the present disclosure is not limited thereto.

[0039] For example, the microbial carrier of the present disclosure may have a second metal film 22 only on one side of the base material 21, a first metal film 12 on this second metal film 22, and microorganisms 13 are carried on this first metal film 12. Further, the microbial carrier of the present disclosure may have a second metal film 22 only on one side of the base material 21, a first metal film 12 on this second metal film 22, microorganisms 13 are carried on the first metal film 12, and microorganisms 13 are also carried on the other side of the base material 11 (the side without the second metal film 22 and the first metal film 12).

[0040] Here, in the case of the microbial carrier 20 shown in FIG. 2, if there is a second metal film 22 on each of the two sides of the base material 21, a first metal film 12 on each of the second metal films 22, and microorganisms 13 are carried on each of the first metal films 12, more microorganisms 13 can be carried. Further, by including a metal that promotes the growth of microorganisms 13 in the first metal film 12, the growth of the microorganisms 13 carried on both sides of the base material 21 can be further promoted.

[0041] In the microbial carrier 20 shown in FIG. 2, since there is a second metal film 22 on the base material 21, even when the base material 21 is made of a non-conductive material or a material with low conductivity, since the second metal film 22 has conductivity, the electrolytic plating method can be preferably used as a method for forming the first metal film 12.

[0042] As a method for forming the second metal film 22 on the base material 21, the electroless plating method can be preferably used. Examples of the material constituting the second metal film 22 include materials containing nickel.

[0043] And as described above, ammonia-oxidizing bacteria and anammox bacteria grow in an environment where zinc, manganese, cobalt, or copper is present. Among these, the presence of zinc is preferred. Therefore, if at least one of zinc, manganese, cobalt, or copper is included in the layer constituting the surface on which ammonia-oxidizing bacteria or anammox bacteria, or both, are supported (the first metal film 12 in the microbial carrier 20 shown in FIG. 2), ammonia-oxidizing bacteria or anammox bacteria, or both, will grow more easily. Therefore, the microbial carrier 20 having the above configuration suppresses the decrease in the supported microorganisms and enables long-term use.

[0044] Hereinafter, each element constituting the microbial carrier 10 and the microbial carrier 20 will be described.

[0045] (Base material) As described above, the base material 11 constituting the microbial carrier 10 shown in FIG. 1 is preferably composed of a conductive material. When the base material 11 is composed of a material having conductivity, an electrolytic plating method can be preferably used as a method for forming the first metal film 12 on the base material 11.

[0046] The base material 11 preferably has a large surface area per unit weight so that more microorganisms can be supported. For example, the base material 11 preferably has pores or irregularities on its surface. Preferred examples of the base material 11 include any of porous carbon, a metal mesh, a metal substrate having an uneven structure, or a metal substrate having through holes.

[0047] On the other hand, in the microbial carrier 20 shown in FIG. 2, since the second metal film 22 is provided on the base material 21, even when the base material 21 constituting the microbial carrier 20 is composed of a non-conductive material or a material having low conductivity, since the second metal film 22 has conductivity, an electrolytic plating method can be preferably used as a method for forming the first metal film 12.

[0048] The substrate 21 preferably has a large surface area per unit weight so that more microorganisms can be supported. For example, the substrate 21 preferably has pores or irregularities on its surface. Suitable examples of the substrate 21 include any of a hydrophilic polymer gel, a nonwoven fabric, a plastic mesh fiber, a porous plastic, and a porous ceramic.

[0049] (First metal film) The first metal film 12 contains at least one of zinc, manganese, cobalt, or copper as the metal. As described above, ammonia-oxidizing bacteria and anammox bacteria are known to grow in an environment where zinc, manganese, cobalt, or copper is present. Among them, the presence of zinc is preferred. Therefore, if at least one of zinc, manganese, cobalt, or copper is contained in the first metal film 12 that constitutes the surface on which ammonia-oxidizing bacteria or anammox bacteria, or both, are supported, ammonia-oxidizing bacteria or anammox bacteria, or both, will be likely to grow. As a method for forming the first metal film 12, an electrolytic plating method is preferably used.

[0050] The film thickness of the first metal film 12 only needs to be such that ammonia-oxidizing bacteria or anammox bacteria, or both, can grow. On the other hand, if the film thickness is unnecessarily large, it may lead to an increase in cost. Also, if the film thickness is unnecessarily large, the first metal film 12 may fill the pores or irregularities of the substrate 11 or substrate 21, and there is a risk that the amount of microorganisms that can be supported will decrease.

[0051] The film thickness of the first metal film 12 can be, for example, 0.1 μm or more and 50 μm or less, preferably 0.2 μm or more and 20 μm or less. If the film thickness of the first metal film 12 is 0.1 μm or more, ammonia-oxidizing bacteria or anammox bacteria, or both can grow. If the film thickness of the first metal film 12 is 50 μm or less, there will be no particular problem in terms of cost or the like. Also, if the film thickness of the first metal film 12 is 50 μm or less, it is possible to suppress the first metal film 12 from filling the holes and irregularities of the base material 11 or the base material 21.

[0052] The film thickness of the above-mentioned first metal film 12 is obtained by identifying the layer constituting the second metal film 22 from the cross-section of a test piece (10 mm × 10 mm in plan view) cut out from the microbial carrier 10 or the microbial carrier 20 using a laser microscope and measuring its thickness.

[0053] (Second metal film) The second metal film 22 is a film provided between the base material 21 and the first metal film 12 in the microbial carrier 20 shown in FIG. 2.

[0054] In the microbial carrier 20 shown in FIG. 2, the second metal film 22 is provided on the base material 21. Therefore, even when the base material 21 is made of a non-conductive material or a material with low conductivity, since the second metal film 22 has conductivity, the electrolytic plating method can be preferably used as a method for forming the first metal film 12. That is, by using the second metal film 22 as a seed layer, the first metal film 12 can be formed by the electrolytic plating method.

[0055] As a method for forming the second metal film 22 on the base material 21, an electroless plating method can be preferably used. As the material constituting the second metal film 22, any material that can be used for the seed layer of the electroplating method can be used, and a material containing nickel can be preferably cited. The second metal film 22 may have a single-layer structure or a multilayer structure. For example, the second metal film 22 may have a two-layer structure in which a lower layer film containing copper is first formed on the base material 21, and an upper layer film containing nickel is formed thereon. By forming the lower layer film having copper, the conductivity can be increased, and accordingly, the upper layer film can be made thinner. As a result, even if it has a two-layer structure, it is possible to reduce the film thickness of the second metal film 22. As a method for forming the lower layer film and the upper layer film, the electroless plating method can be used for both.

[0056] The film thickness of the second metal film 22 only needs to be a thickness that can act as a seed layer for forming the first metal film 12 by the electroplating method. On the other hand, if the film thickness is unnecessarily large, there is a risk of increasing the cost. Also, if the film thickness is unnecessarily large, the second metal film 22 may fill the holes and irregularities of the base material 21, and the amount of microorganisms that can be supported may decrease.

[0057] The film thickness of the second metal film 22 can be, for example, 0.1 μm or more and 20 μm or less, preferably 0.2 μm or more and 10 μm or less. If the film thickness of the second metal film 22 is 0.1 μm or more, it can act as a seed layer for forming the first metal film 12 by the electroplating method. If the film thickness of the second metal film 22 is 20 μm or less, problems such as from the perspective of cost do not particularly occur. Also, if the film thickness of the second metal film 22 is 20 μm or less, it is possible to suppress the second metal film 22 from filling the holes and irregularities of the base material 21.

[0058] The above-mentioned film thickness of the second metal film 22 is obtained by identifying the layer constituting the second metal film 22 with a laser microscope from the cross-section of a test piece (10 mm × 10 mm in plan view) cut out from the microorganism carrier 20 and measuring its thickness.

[0059] (Microorganism) The microorganism 13 supported on the microorganism carrier 10 and the microorganism carrier 20 includes at least one of ammonia-oxidizing bacteria or anammox bacteria. The ammonia-oxidizing bacteria convert ammonia nitrogen (NH4-N) into nitrous nitrogen (NO2-N) (partial nitritation process), and the anammox bacteria utilize the anammox reaction to remove nitrogen.

[0060] When the microorganism 13 supported on the microorganism carrier 10 or the microorganism carrier 20 includes both ammonia-oxidizing bacteria and anammox bacteria, one microorganism carrier 10 or one microorganism carrier 20 can perform the process of converting the above ammonia nitrogen (NH4-N) into nitrous nitrogen (NO2-N) (partial nitritation treatment) and the process of removing nitrogen by utilizing the anammox reaction.

[0061] On the other hand, when the microorganism 13 supported on the microorganism carrier 10 and the microorganism carrier 20 includes only one of ammonia-oxidizing bacteria or anammox bacteria, first, a process of converting ammonia nitrogen (NH4-N) into nitrous nitrogen (NO2-N) (partial nitritation treatment) is performed using the microorganism carrier 10 or the microorganism carrier 20 having ammonia-oxidizing bacteria, and then, a process of removing nitrogen by utilizing the anammox reaction is performed using the microorganism carrier 10 or the microorganism carrier 20 having anammox bacteria.

[0062] As the ammonia-oxidizing bacteria supported on the microorganism carrier 10 and the microorganism carrier 20, any bacteria that can convert ammonia nitrogen (NH4-N) into nitrous nitrogen (NO2-N) can be used. For example, bacteria belonging to the genera Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosolobus, Nitrosovibrio, etc. can be used. For example, the ammonia-oxidizing bacteria can be obtained from activated sludge recovered from a conventional wastewater treatment facility.

[0063] As the anammox bacteria supported on the microbial carrier 10 and the microbial carrier 20, any bacteria capable of performing the anammox reaction can be used. For example, Candidatus Brocadia, Candidatus Kuenenia, Candidatus Jettenia, Candidatus Anammoxoglobus, Candidatus Scalindua, Candidatus Anammoximicrobium, etc. can be used. For example, the anammox bacteria can be obtained from activated sludge recovered from conventional wastewater treatment facilities.

[0064] <Method for manufacturing microbial carrier> Next, the method for manufacturing the microbial carrier of the present disclosure will be described. FIG. 3 is a diagram showing an example of the method for manufacturing the microbial carrier of the present disclosure. More specifically, FIG. 3 is a diagram showing an example of the method for manufacturing the microbial carrier 10 shown in FIG. 1. Further, FIG. 4 is a diagram showing another example of the method for manufacturing the microbial carrier of the present disclosure. More specifically, FIG. 4 is a diagram showing an example of the method for manufacturing the microbial carrier 20 shown in FIG. 2.

[0065] First, the method for manufacturing the microbial carrier shown in FIG. 3 will be described. In the method for manufacturing the microbial carrier shown in FIG. 3, first, as shown in FIG. 3(a), a base material 11 is prepared, and then, as shown in FIG. 3(b), a first metal film 12 is formed on the base material 11 (first metal film forming step). The first metal film 12 contains at least one of zinc, manganese, cobalt, or copper as the metal.

[0066] Here, the base material 11 of the microbial carrier 10 shown in FIG. 1 is preferably composed of a conductive material. More specifically, the base material 11 is preferably any one of porous carbon, a metal mesh, a metal substrate having an uneven structure, or a metal substrate having through holes. In this case, the electrolytic plating method is preferably used as the method for forming the first metal film 12 on the base material 11.

[0067] Thereafter, as shown in Fig. 3(c), microorganisms 13 are supported on the first metal film 12 (microorganism support step). As a method of support, a method in which the laminate 10A shown in Fig. 3(b) (a laminate in which the first metal film 12 is formed on the substrate 11) is immersed in a liquid containing the microorganisms 13 is preferably used. By this immersion, the microorganisms 13 are adhered and fixed on the first metal film 12. In the microorganism carrier 10, the form of support of the microorganisms 13 is a form in which the microorganisms 13 are adhered and fixed on the first metal film 12. After the microorganisms 13 are supported, the liquid contained in the microorganism carrier 10 may be appropriately removed by treatment such as suction filtration.

[0068] In addition, in the method for manufacturing the microorganism carrier shown in Fig. 3, a manufacturing method is shown in which the first metal film 12 is formed on both surfaces of the substrate 11, and the microorganisms 13 are supported on each of the first metal films 12, but the method for manufacturing the microorganism carrier of the present disclosure is not limited to this.

[0069] For example, a manufacturing method may be such that the first metal film 12 is formed only on one surface of the substrate 11, and the microorganisms 13 are supported on this first metal film 12. Also, a manufacturing method may be such that the first metal film 12 is formed only on one surface of the substrate 11, the microorganisms 13 are supported on this first metal film 12, and the microorganisms 13 are also supported on the other surface of the substrate 11 (the surface without the first metal film 12).

[0070] Here, if it is a manufacturing method in which the first metal film 12 is formed on both surfaces of the substrate 11 and the microorganisms 13 are supported on each of the first metal films 12, as in the method for manufacturing the microorganism carrier shown in Fig. 3, more microorganisms 13 can be supported by the microorganism carrier 10. And by including a metal that promotes the growth of the microorganisms 13 in the first metal film 12, the growth of the microorganisms 13 supported on both surfaces of the substrate 11 can be further promoted.

[0071] Next, a method for manufacturing a microbial carrier shown in FIG. 4 will be described. In the method for manufacturing a microbial carrier shown in FIG. 4, first, as shown in FIG. 4(a), a substrate 21 is prepared. Then, as shown in FIG. 4(b), a second metal film 22 is formed on the substrate 21 (second metal film forming step). The substrate 21 may be made of a non-conductive material or a material with low conductivity. For example, it can be any of a hydrophilic polymer gel, a non-woven fabric, a plastic mesh fiber, a porous plastic, or a porous ceramic. As a method for forming the second metal film 22 on the substrate 21, an electroless plating method is preferably used. Examples of the material constituting the second metal film 22 include materials containing nickel.

[0072] Next, as shown in FIG. 4(c), a first metal film 12 is formed on the second metal film 22 (first metal film forming step). The first metal film 12 contains at least one of zinc, manganese, cobalt, or copper as a metal. As a method for forming the first metal film 12 on the second metal film 22, an electrolytic plating method is preferably used.

[0073] Thereafter, as shown in FIG. 4(d), microorganisms 13 are supported on the first metal film 12 (microorganism supporting step). As a supporting method, a method in which the laminate 20B shown in FIG. 4(c) (a laminate in which a second metal film 22 is formed on a substrate 21 and a first metal film 12 is formed on the second metal film 22) is immersed in a liquid containing the microorganisms 13 is preferably used. By this immersion, the microorganisms 13 are adhered and fixed on the first metal film 12. In the microbial carrier 20, the form of supporting the microorganisms 13 is a form in which the microorganisms 13 are adhered and fixed on the first metal film 12. After the microorganisms 13 are supported, the liquid contained in the microbial carrier 20 may be appropriately removed by a treatment such as suction filtration.

[0074] In the method for manufacturing a microbial carrier shown in FIG. 4, since the second metal film 22 is formed on the base material 21, even when the base material 21 is made of a non-conductive material or a material with low conductivity, the second metal film 22 has conductivity. Therefore, as a method for forming the first metal film 12, an electrolytic plating method can be preferably used.

[0075] Note that in the method for manufacturing a microbial carrier shown in FIG. 4, the second metal films 22 are respectively formed on both surfaces of the base material 21, the first metal films 12 are respectively formed on the second metal films 22, and the microorganisms 13 are respectively supported on the first metal films 12. Although a manufacturing method is shown, the manufacturing method of the microbial carrier of the present disclosure is not limited to this.

[0076] For example, the second metal film 22 may be formed only on one side of the base material 21, the first metal film 12 may be formed on the second metal film 22, and the microorganism 13 may be supported on the first metal film 12. Further, the second metal film 22 may be formed only on one side of the base material 21, the first metal film 12 may be formed on the second metal film 22, the microorganism 13 may be supported on the first metal film 12, and the microorganism 13 may also be supported on the other side of the base material 21 (the side without the second metal film 22 and the first metal film 12).

[0077] As described above, the microbial carrier and the method for manufacturing the microbial carrier according to the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments. The above-described embodiments are examples, and those having substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibiting the same operational effects are included in the technical scope of the present disclosure in any case.

Example

[0078] Hereinafter, examples and comparative examples of the embodiments of the present disclosure will be shown and described in detail. However, the embodiments of the present disclosure are not limited to these examples.

[0079] (Example 1) <Base material preparation> As the base material, a polyester non-woven fabric cell sheet CS-50 (manufactured by Maeda Kogyo Sen’i Co., Ltd.) was cut out into a circle with a diameter of 90 mm and was subjected to electroless nickel plating by the following treatment.

[0080] <Catalyst treatment> The above non-woven fabric cell sheet was immersed in an aqueous solution containing 0.3 g / L of palladium chloride, 15.0 g / L of stannous chloride, and 200 mL / L of hydrochloric acid at 30 °C for 10 minutes, then washed with water, and then dried at a temperature of 80 °C in the air.

[0081] <Activation treatment> The non-woven fabric cell sheet subjected to the above catalyst treatment was rinsed with hydrochloric acid water containing 200 mL / L of hydrochloric acid for 3 minutes.

[0082] <Electroless plating treatment> The non-woven fabric cell sheet subjected to the above activation treatment was immersed in an aqueous solution containing 25 g / L of nickel sulfate, 25 g / L of sodium hypophosphite, and 50 g / L of sodium pyrophosphate under the conditions of pH 10.5 and 50 °C for 10 minutes, then washed with water, and then dried at a temperature of 80 °C in the air.

[0083] <Electrolytic plating treatment> Next, the non-woven fabric cell sheet subjected to the above electroless nickel plating treatment was used as the negative electrode, and an aqueous solution containing 200 g / L of zinc sulfate and 30 g / L of ammonium sulfate was put into an electrolytic cell with a 1 mm thick zinc plate as the positive electrode. Electrolytic plating treatment was carried out under the conditions of pH 4.0, 40 °C, and a current density of 10 mA / cm 2 for 5 minutes. Then, the non-woven fabric cell sheet subjected to the electrolytic plating treatment was taken out, washed with water, and dried at a temperature of 80 °C in the air.

[0084] <Microorganism loading> Next, 15 mg of the microbial agent Hypolca S (manufactured by Sanming Chemical Co., Ltd.) was dissolved in 100 mL of warm water at 30°C and placed in a stainless-steel bath. Into this solution, the non-woven fabric sheet Celsheet that had been subjected to the above electrolytic plating treatment was immersed at 30°C for 3 hours to attach microorganisms containing both ammonia-oxidizing bacteria and anammox bacteria. In this way, the microbial carrier of Example 1 was prepared.

[0085] <Weight measurement on day 0> Thereafter, the above microbial carrier was taken out of the above solution, suction-filtered with a Buchner funnel having a diameter of 90 mm, and its weight was measured. The numerical value of this measurement result is described as the value on day 0 of Example 1 in Table 1 below.

[0086] <Weight measurement on day 2> Next, the above microbial carrier was immersed in a stainless-steel bath containing 100 mL of an aqueous solution containing 40 g / L of glucose, 8 g / L of ammonium sulfate, and 9 g / L of yeast extract, and left at room temperature for 48 hours. Thereafter, the microbial carrier was taken out of the stainless-steel bath, co-washed in another stainless-steel bath containing 100 mL of an ammoniacal yeast extract aqueous solution, and then suction-filtered with a Buchner funnel having a diameter of 90 mm, and its weight was measured. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 described above. The numerical value of this measurement result is described as the value on day 2 of Example 1 in Table 1 below.

[0087] <Weight measurement from day 4 to day 10> Next, the step of immersing the microbial carrier that had been left standing in the above aqueous solution for 48 hours, suction-filtering and measuring its weight after co-washing with an ammoniacal yeast extract aqueous solution after leaving it standing in the above aqueous solution for 48 hours was performed 4 times. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 described above. The numerical values of these measurement results are described as the values from day 4 to day 10 of Example 1 in Table 1 below.

[0088] (Comparative Example 1) <Substrate preparation> As the base material, the same polyester nonwoven fabric cell sheet CS-50 (manufactured by Maeda Kogyo Sen’i Co., Ltd.) as the base material prepared in Example 1 was cut out into a circle with a diameter of 90 mm. Neither electroless nickel plating treatment nor electroplating treatment performed in Example 1 above was applied to the base material of this Comparative Example 1.

[0089] <Microorganism loading> Next, 15 mg of the microorganism agent Hypolca S (manufactured by Sanming Chemical Co., Ltd.) was dissolved in 100 mL of warm water at 30 °C and placed in a stainless steel bath. The above nonwoven fabric cell sheet (nonwoven fabric cell sheet without either electroless nickel plating treatment or electroplating treatment) was infiltrated into this solution at 30 °C for 3 hours to attach microorganisms containing both ammonia-oxidizing bacteria or anammox bacteria. In this way, the microorganism carrier of Comparative Example 1 was produced.

[0090] <Weight measurement on day 0> Thereafter, the microorganism carrier of Comparative Example 1 was taken out from the above solution, suction-filtered with a Buchner funnel having a diameter of 90 mm, and the weight was measured. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 of Example 1 above. The numerical value of this measurement result is described as the numerical value on day 0 of Comparative Example 1 in Table 1 below.

[0091] <Weight measurement on day 2> Next, the microorganism carrier of Comparative Example 1 above was immersed in a stainless steel bath containing 100 mL of an aqueous solution with a concentration of 40 g / L of glucose, 8 g / L of ammonium sulfate, and 9 g / L of yeast extract in the same manner as in Example 1, and left at room temperature for 48 hours. Thereafter, the microorganism carrier of Comparative Example 1 was taken out from the stainless steel bath, co-washed in another stainless steel bath containing 100 mL of an aqueous ammonia yeast extract solution, and then suction-filtered with a Buchner funnel having a diameter of 90 mm, and the weight was measured. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 above. The numerical value of this measurement result is described as the numerical value on day 2 of Comparative Example 1 in Table 1 below.

[0092] <Weight measurement from day 4 to day 10> Next, for the microbial carrier of Comparative Example 1 that had been left standing in the above aqueous solution for 48 hours, the step of leaving it standing in the above aqueous solution for 48 hours, co-washing with an aqueous solution of ammoniacal yeast extract, and then performing suction filtration and weight measurement was carried out 4 times. The weight measurement was performed using the same apparatus and the same method as the weight measurement on the 0th day described above. The numerical values of these measurement results are described in Table 1 below as the numerical values for the 4th to 10th days of Comparative Example 1.

[0093] (Comparative Example 2) <Substrate Preparation> As the substrate, the same polyester non-woven fabric cell sheet CS-50 (manufactured by Maeda Kosen Co., Ltd.) as the substrate prepared in Example 1 was cut out into a circle with a diameter of 90 mm, and electroless nickel plating treatment was performed in the same manner as in Example 1 by the following treatment. Note that the electrolytic plating treatment performed in Example 1 above was not performed on the substrate of this Comparative Example 2.

[0094] <Catalyst Treatment> The above non-woven fabric cell sheet was immersed in an aqueous solution containing 0.3 g / L of palladium chloride, 15.0 g / L of stannous chloride, and 200 mL / L of hydrochloric acid at 30 °C for 10 minutes, then washed with water, and then dried in the air at a temperature of 80 °C.

[0095] <Activation Treatment> The non-woven fabric cell sheet subjected to the above catalyst treatment was rinsed with hydrochloric acid water containing 200 mL / L of hydrochloric acid for 3 minutes.

[0096] <Electroless Plating Treatment> The non-woven fabric cell sheet subjected to the above activation treatment was immersed in an aqueous solution containing 25 g / L of nickel sulfate, 25 g / L of sodium hypophosphite, and 50 g / L of sodium pyrophosphate under the conditions of pH 10.5 and 50 °C for 10 minutes, then washed with water, and then dried in the air at a temperature of 80 °C.

[0097] <Microorganism Loading> Next, 15 mg of the microbial agent Hypolca S (manufactured by Sanming Chemical Co., Ltd.) was dissolved in 100 mL of warm water at 30°C and placed in a stainless-steel bath. The non-woven fabric sheet Celcete that had been subjected to the electroless plating treatment described above was immersed in this solution at 30°C for 3 hours. In this way, the microbial carrier of Comparative Example 2 was prepared.

[0098] <Weight measurement on day 0> Subsequently, the microbial carrier of Comparative Example 2 was taken out of the above solution, suction-filtered through a Buchner funnel with a diameter of 90 mm, and the weight was measured. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 in Example 1 described above. The numerical value of this measurement result is described as the numerical value on day 0 of Comparative Example 2 in Table 1 below.

[0099] <Weight measurement on day 2> Next, the microbial carrier of Comparative Example 2 described above was immersed in a stainless-steel bath containing 100 mL of an aqueous solution with a concentration of glucose of 40 g / L, ammonium sulfate of 8 g / L, and yeast extract of 9 g / L, and left at room temperature for 48 hours. Subsequently, the microbial carrier of Comparative Example 2 was taken out of the stainless-steel bath, co-washed in another stainless-steel bath containing 100 mL of an ammoniacal yeast extract aqueous solution, then suction-filtered through a Buchner funnel with a diameter of 90 mm, and the weight was measured. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 described above. The numerical value of this measurement result is described as the numerical value on day 2 of Comparative Example 2 in Table 1 below.

[0100] <Weight measurement from day 4 to day 10> Next, the step of immersing the microbial carrier of Comparative Example 2 that had been left standing in the above aqueous solution for 48 hours, then co-washing with the ammoniacal yeast extract aqueous solution, and then suction-filtering and measuring the weight was performed 4 times. The weight measurement was performed using the same apparatus and the same method as the weight measurement on day 0 described above. The numerical values of these measurement results are described as the numerical values from day 4 to day 10 of Comparative Example 2 in Table 1 below.

[0101]

Table 1

[0102] As shown in Table 1, in Example 1, the weight continuously increased from the 0th day to the 10th day, and no weight loss was observed during this period. This increase in weight is due to the growth of the microorganisms supported on the microorganism carrier of Example 1.

[0103] On the other hand, as shown in Table 1, in Comparative Example 1, an increase in weight was observed from the 0th day to the 2nd day, but thereafter (from the 4th day to the 10th day), it decreased. This decrease in weight is due to the decrease in the microorganisms supported on the microorganism carrier of Comparative Example 1.

[0104] Also, as shown in Table 1, in Comparative Example 2, an increase in weight was observed from the 0th day to the 4th day, but thereafter (from the 4th day to the 10th day), it decreased. This decrease in weight is due to the decrease in the microorganisms supported on the microorganism carrier of Comparative Example 1.

[0105] As described above, in the microorganism carrier of Example 1, the decrease in the supported microorganisms was suppressed, and rather, the growth of the supported microorganisms was confirmed. It was confirmed that the microorganism carrier of Example 1 can be used for a long period of time.

Explanation of Signs

[0106] 10, 20 Microorganism carrier 10A Laminate 11, 21 Base material 12 First metal film 13 Microorganisms 20A, 20B Laminate 22 Second metal film 150 Wastewater treatment process 160 Treatment tank 161 Wastewater 162 Sludge 165 Oxygen supply machine 166 Pipe 170 Sedimentation tank 171 Treated water 172 Sludge

Claims

1. A microbial carrier having a first metal film containing at least one of zinc, manganese, cobalt, or copper on a substrate, wherein a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria is supported on the first metal film.

2. The microbial carrier according to claim 1, wherein the substrate is made of a conductive material.

3. The microbial carrier according to claim 2, wherein the substrate is any one of porous carbon, a metal mesh, a metal substrate having a concavo-convex structure, or a metal substrate having through holes.

4. The microbial carrier according to claim 1, having a second metal film between the substrate and the first metal film.

5. The microbial carrier according to claim 4, wherein the second metal film contains nickel.

6. The microbial carrier according to claim 4 or claim 5, wherein the substrate is any one of a hydrophilic polymer gel, a non-woven fabric, plastic mesh fibers, porous plastic, or porous ceramic.

7. A first metal film forming step of forming a first metal film containing at least one of zinc, manganese, cobalt, or copper on a substrate by an electrolytic plating method; A microbial loading step of loading a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria on the first metal film; A method for manufacturing a microbial carrier, comprising:

8. The method for manufacturing a microbial carrier according to claim 7, wherein the substrate is any one of porous carbon, a metal mesh, a metal substrate having a concavo-convex structure, or a metal substrate having through holes.

9. A second metal film forming step of forming a second metal film containing nickel on a substrate by an electroless plating method; A first metal film forming step of forming a first metal film containing at least one of zinc, manganese, cobalt, or copper on the second metal film by an electrolytic plating method; A microbial loading step of loading a microorganism containing at least one of ammonia-oxidizing bacteria or anammox bacteria on the first metal film; A method for manufacturing a microbial carrier, comprising:

10. The method for manufacturing a microbial carrier according to claim 9, wherein the substrate is any one of a hydrophilic polymer gel, a non-woven fabric, plastic mesh fibers, porous plastic, or porous ceramic.

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