Denitrification filter material, water quality purification device, and aquatic organism distribution management system

Abstract

[Problem] To provide a denitrification filter material in which the form thereof is maintained without collapsing and which is digested only when fed on by denitrifying bacteria. [Solution] A denitrification filter material according to the present invention is configured from a biodegradable melt-kneaded resin composition containing (A) a water-insoluble and / or non-seawater-soluble biodegradable resin component and (B) a biomass polysaccharide polymer component. The component (A) is preferably an ester-bonded polymer, and is more preferably one or more selected from polybutylene succinate adipate, polyhydroxyalkanoate, and polycaprolactone. The component (B) preferably contains a biomass polysaccharide polymer component having a helical molecular structure. A water purification device comprises: a denitrification tank to which water being treated is supplied; the aforementioned denitrification filter material, which is accommodated in the denitrification tank and fixes aerobic denitrifying bacteria for reducing nitrate nitrogen in the water being treated; and an air supply mechanism that supplies air to the water being treated.

Description

Denitrification filter media, water purification equipment, and aquatic organism distribution management system

[0001] The present invention relates to a denitrification filter medium, a water purification device, and an aquatic organism distribution management system.

[0002] Denitrification equipment is widely used in aquatic aquaculture and wastewater treatment facilities.

[0003] A denitrification system includes a denitrification tank and a denitrification filter medium containing denitrifying bacteria that is housed within the tank. The denitrification bacteria reduce nitrate and nitrite nitrogen contained in the water supplied to the denitrification tank under aerobic conditions. Porous cellulose in granular, block, or layered form is widely used as the denitrification filter medium. The cellulose serves as food for the denitrifying bacteria, increasing their numbers and improving denitrification capacity.

[0004] International Publication No. 2017 / 110296 Pamphlet

[0005] However, in the invention described in Patent Document 1, if cellulose is added at a high concentration, the shape of the denitrification filter media collapses, and the crushed cellulose disperses into the treated water even though the denitrification bacteria are not using it as food, which can result in contamination of the treated water. Therefore, it is necessary to adjust the amount of denitrification filter media supplied, but this increases the frequency of denitrification filter media supply and increases the burden on the denitrification equipment manager.

[0006] Furthermore, bacteria can penetrate deep into the cellulose mass, which then becomes strongly anaerobic, so sulfate-reducing bacteria become dominant rather than aerobic denitrifying bacteria, raising concerns about the risk of hydrogen sulfide generation.

[0007] The present invention has been made in consideration of these problems, and aims to provide a denitrification filter medium that maintains its shape and is digested only when denitrifying bacteria feed on it. It also aims to provide a water purification device that uses the denitrification filter medium and an aquatic organism distribution management system that uses the water purification device.

[0008] As a result of intensive research into solving the above problems, the present inventors have found that by using a biodegradable melt-kneaded resin composition containing a water-insoluble and / or sea-water-insoluble resin component as a denitrification filter material, the denitrification filter material will not lose its shape, and by making the resin component biodegradable, it will be possible to enable complete digestion by denitrification bacteria, thereby achieving the above problems, and have completed the present invention. Specifically, the present invention provides the following.

[0009] The first aspect of the present invention provides a denitrification filter medium composed of a biodegradable melt-kneaded resin composition containing (A) a water-insoluble and / or sea-water-insoluble resin component that is biodegradable, and (B) a biomass polysaccharide polymer component.

[0010] According to the first aspect of the present invention, the denitrification filter material is a biodegradable melt-kneaded resin composition containing a water-insoluble and / or seawater-insoluble resin component. This allows the biomass polysaccharide polymer component contained in the denitrification filter material to be solidified by the resin component, and the shape of the denitrification filter material does not collapse until the denitrification bacteria consume it. In addition, unlike when the resin component is water-soluble, the denitrification filter material does not foam in the aquarium. Furthermore, because the resin component is biodegradable, it can be completely digested by the denitrification bacteria, and the resin component does not cause water pollution.

[0011] Furthermore, biodegradation begins preferentially on the surface of the lumps of the melt-kneaded resin composition and on the inside of the voids of the biomass polysaccharide polymer components, allowing aerobic conditions to be maintained even inside the lumps, and aerobic denitrifying bacteria become dominant over sulfate-reducing bacteria, reducing the risk of hydrogen sulfide generation.

[0012] Therefore, according to the first aspect of the invention, it is possible to provide a denitrification filter medium that maintains its shape and is digested only when denitrification bacteria feed on it.

[0013] A second feature of the invention is the denitrification filter medium according to the first feature of the invention, wherein the component (A) is an ester-bonded polymer.

[0014] According to the invention relating to the second feature, even if the resin component is water-insoluble and / or seawater-insoluble, it is decomposed into harmless and non-toxic compounds by simple hydrolysis of the ester main chain inside the body of the denitrifying bacteria. Therefore, the shape of the denitrifying filter material does not collapse until the denitrifying bacteria feed on the biomass polysaccharide polymer component, and it is possible to achieve both the objective of preventing water pollution caused by the resin component.

[0015] The third aspect of the invention is the first aspect of the invention, and provides a denitrification filter medium in which the component (A) contains one or more selected from polybutylene succinate adipate, polyhydroxyalkanoate, and polycaprolactone.

[0016] When the denitrification apparatus is intended for use in the cultivation of marine organisms, the treated water supplied to the apparatus is seawater. In this case, component (A) must be marine biodegradable. According to the third aspect of the invention, component (A) is marine biodegradable, making it applicable to the cultivation of marine organisms.

[0017] A fourth aspect of the invention is the first aspect of the invention, and provides a denitrification filter medium in which the component (B) contains a biomass polysaccharide polymer component having a helical molecular structure.

[0018] According to the invention relating to the fourth feature, the feed components can be included in the composition at a relatively high proportion compared to other biomass components, i.e., biomass components that do not have a helical molecular structure, and the feed components can be highly concentrated. As a result, the frequency of supplying denitrification filter media can be reduced, and the burden on the manager of the denitrification equipment can be reduced.

[0019] The fifth aspect of the invention provides a water purification device comprising a denitrification tank to which water to be treated is supplied, a denitrification filter material according to any one of the first to fourth aspects of the invention contained in the denitrification tank and adapted to settle aerobic denitrifying bacteria that reduce nitrate nitrogen in the water to be treated, and an air supply mechanism that supplies air to the water to be treated.

[0020] According to a sixth aspect of the invention, there is provided a water purification device according to the first aspect of the invention, comprising: a denitrification tank to which water to be treated is supplied; a denitrification filter material housed in the denitrification tank and adapted to settle aerobic denitrification bacteria that reduce nitrate nitrogen in the water to be treated; and a denitrification air supply mechanism disposed at the bottom of the denitrification tank and adapted to continuously perform an oxygen intake operation by supplying air to the water to be treated stored in the denitrification tank at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, thereby exposing the denitrification filter material to the air, thereby promoting the denitrification reaction by the denitrification bacteria under aerobic conditions.

[0021] According to the sixth aspect of the invention, air is supplied from the bottom of the denitrification tank at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, and the denitrification reaction is carried out while stirring the water to be treated and the denitrification filter media throughout the entire denitrification tank from the top to the bottom of the denitrification tank using the upward flow of air, thereby making it possible to efficiently and stably denitrify the water to be treated throughout the entire denitrification tank under aerobic conditions.

[0022] The seventh aspect of the invention is the sixth aspect of the invention, and provides a water purification device having an air flow regulating member that is arranged above the air discharge part of the denitrification air supply mechanism and that regulates the flow direction of the upward flow of air supplied from the air discharge part to the water to be treated and concentrates it at one location, thereby circulating the water to be treated and the denitrification filter material throughout the entire denitrification tank.

[0023] According to the seventh feature of the present invention, by placing an airflow control member above the air discharge section of the denitrification air supply mechanism, the upward flow of the discharged air is concentrated in one location, achieving uniform circulation of the water to be treated and the denitrification filter media. This promotes mixing throughout the denitrification tank, optimizing the activity of denitrifying bacteria under aerobic conditions and improving the efficiency of the denitrification process. Furthermore, by suppressing local mixing and retention and maintaining appropriate dispersion of the denitrification filter media, the operating stability of the device is improved, enabling stable denitrification performance to be maintained over the long term.

[0024] The eighth aspect of the invention is the sixth aspect of the invention, and provides a water purification device having a nitrifying filter medium housed in the denitrification tank, which settles aerobic nitrifying bacteria that oxidize ammonium nitrogen in the water to be treated.

[0025] According to the eighth aspect of the present invention, by providing a nitrifying filter medium in the denitrification tank that allows nitrifying bacteria to settle, it is possible to effectively oxidize ammonia nitrogen in the treated water and promote its conversion to nitrate nitrogen. This stabilizes the supply of nitrate nitrogen in the early stages of the denitrification process, improving the efficiency of nitrogen removal by denitrifying bacteria. Furthermore, the presence of the nitrifying filter medium directly oxidizes ammonia nitrogen in the denitrification tank, improving water quality and creating a favorable environment for aerobic microorganisms to grow.

[0026] The ninth aspect of the invention is the first aspect of the invention, and provides a water purification device comprising: a nitrification tank to which the water to be treated is supplied; a nitrification filter material housed in the nitrification tank and adapted to settle aerobic nitrifying bacteria that oxidize ammonia nitrogen in the water to be treated; and a nitrification air supply mechanism disposed at the bottom of the nitrification tank and adapted to continuously perform an oxygen intake operation by supplying air to the water to be treated stored in the nitrification tank at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, thereby exposing the nitrification filter material to the air, thereby promoting the nitrification reaction by the nitrifying bacteria under aerobic conditions.

[0027] According to the ninth aspect of the present invention, a nitrification filter medium is placed in the nitrification tank, and air is continuously supplied to the water being treated by a nitrification air supply mechanism located at the bottom, providing an environment in which nitrifying bacteria can efficiently oxidize ammonia nitrogen under stable aerobic conditions. This promotes the nitrification reaction and stabilizes the production of nitrate nitrogen, which in turn facilitates the subsequent denitrification process and improves nitrogen removal efficiency.

[0028] The invention according to a tenth feature is the invention according to the ninth feature, and provides a water purification device having an air flow regulating member that is arranged above the nitrification air supply mechanism and that regulates the flow direction of the upward flow of air supplied from the nitrification air supply mechanism to the water to be treated and concentrates it in one place, thereby circulating the water to be treated and the nitrification filter material throughout the nitrification tank.

[0029] According to the tenth feature of the present invention, an airflow control member is placed above the nitrification air supply mechanism, concentrating the upward flow of the supplied air in one location, thereby efficiently circulating the water being treated and the nitrification filter media in the nitrification tank. This ensures uniform distribution of nitrifying bacteria and maintains aerobic conditions throughout the tank, thereby efficiently oxidizing ammonia nitrogen and improving the stability of the nitrification process. Furthermore, the circulation prevents localized accumulation and concentration imbalances, enabling uniform treatment throughout the nitrification tank. This improves the treatment efficiency of the entire water purification system and makes it easier to maintain performance over long periods of operation.

[0030] The invention according to an eleventh feature is the invention according to the sixth or ninth feature, and provides an aquatic organism distribution management system having a distribution station that is installed in a distribution area where consumers of aquatic organisms exist, and that breeds the aquatic organisms in the treated water from breeding tanks while denitrifying the treated water using the water purification device.

[0031] According to the eleventh feature of the invention, aquatic organisms can be raised and stocked at a distribution station while maintaining optimal water quality in the breeding tanks, thereby preventing the transfer of unpleasant odors to the aquatic organisms. Additionally, the aquatic organisms can be fed while being stocked, allowing them to regain their flavor and fatten up. By installing a distribution station with these functions within a distribution area, consumers within the distribution area can obtain aquatic organisms in a shorter time than if they were to purchase them from a fishing port or central wholesale market. This allows the aquatic organisms to be delivered to consumers in a state where they have sufficient flavor and are free from odors.

[0032] The twelfth aspect of the invention is the eleventh aspect of the invention, which provides an aquatic organism distribution management system having: a distribution management server that stores installation location information indicating the installation location of the distribution station and aquatic organism information including the type, size, and number of the aquatic organisms being raised in the treated water at the distribution station; and a communication device that can send and receive distribution management information including the installation location information and the aquatic organism information between the distribution management server and the consumer terminal of the consumer.

[0033] According to the twelfth feature of the invention, a distribution management server is provided, which stores information about the locations of distribution stations and aquatic organism information, including the type, size, and number of aquatic organisms. This information can be communicated with consumer terminals, allowing consumers to grasp the inventory status of distribution stations in real time and efficiently obtain the aquatic organisms they need. This eliminates the need for consumers to travel to distant fishing ports or central wholesale markets, improving distribution efficiency and enabling consumers to receive highly fresh aquatic organisms in the appropriate condition. Furthermore, inventory management is made easier for sellers, allowing them to appropriately adjust supply according to demand, optimizing the overall distribution process and improving the convenience and economy of aquatic organism distribution.

[0034] The thirteenth aspect of the invention is the twelfth aspect of the invention, wherein the distribution stations are installed at multiple locations, and the distribution management server, when the distribution management information includes location information of the consumer terminal, provides an aquatic organism distribution management system that includes the distance between the consumer terminal and the distribution station in the distribution management information based on the location information and installation location information of the distribution station.

[0035] According to the thirteenth aspect of the present invention, multiple distribution stations are installed, and the distribution management server takes into account the location information of the consumer's device and includes the distance to each distribution station in the distribution management information. This allows consumers to easily identify the nearest distribution station and quickly obtain aquatic organisms. This optimizes distribution routes, reduces transportation costs and time, and allows aquatic organisms to be provided in a state that maintains their freshness. Furthermore, for sellers, this allows them to develop distribution strategies that utilize consumer location information, enabling efficient supply according to demand, improving the accuracy of overall distribution management and leading to increased sales opportunities.

[0036] The invention relating to the fourteenth feature is the invention relating to the twelfth feature, wherein the communication device is capable of transmitting and receiving the distribution management information between the distribution management server and a seller terminal of a seller who sells the aquatic organisms using the distribution station, and the distribution management server includes replenishment information in the distribution management information and transmits it to the seller terminal when the number of aquatic organisms stored in the distribution station is below a predetermined number.

[0037] According to the fourteenth feature of the invention, the seller terminal and the distribution management server are enabled to communicate with each other, and when the inventory of aquatic organisms stored in the distribution station falls below a predetermined number, replenishment information is automatically sent to the seller terminal, allowing the seller to grasp the inventory status in real time and replenish at the appropriate time. This prevents lost sales opportunities due to stockouts, realizes a stable supply, and reduces the occurrence of unnecessary excess inventory. Furthermore, by improving the efficiency of replenishment, the management burden of the entire distribution system is reduced, and an environment is created where consumers can always purchase fresh aquatic organisms in a stable manner, improving the convenience and reliability of the distribution system.

[0038] The invention of the fifteenth feature is the invention of the sixth or ninth feature, and is an aquatic organism distribution management method for distributing aquatic organisms using a distribution station that is installed in a distribution area where consumers of aquatic organisms are present, and that raises aquatic organisms in the treated water from breeding tanks while denitrifying the treated water using a water purification device, the aquatic organism distribution management method comprising: a reception process for receiving inquiry information inquiring about the inventory status of the aquatic organisms from the consumer terminal of the consumer; and a distribution management information transmission process for, when the inquiry information is received, reading distribution management information including installation location information indicating the installation location of the distribution station and aquatic organism information including the type, size, and number of the aquatic organisms being raised in the treated water at the distribution station from a distribution management server that stores the installation location information and the aquatic organism information, and transmitting the distribution management information to the consumer terminal.

[0039] According to the fifteenth feature of the invention, in response to inquiries from consumer terminals, the distribution management server provides distribution management information, including the locations of distribution stations and the inventory status of aquatic organisms, allowing consumers to check the type and quantity of aquatic organisms they need in real time and select the most suitable supplier. This not only allows consumers to obtain aquatic organisms efficiently and quickly, but also prevents lost sales opportunities due to uneven inventory distribution. Furthermore, facilitating information sharing throughout the distribution chain allows for appropriate replenishment plans to be made in response to demand, promoting distribution optimization. Furthermore, because aquatic organisms are delivered to consumers in an appropriate, managed environment, this contributes to maintaining freshness and quality, improving the reliability of the distribution system.

[0040] The sixteenth aspect of the invention is the fifteenth aspect of the invention, wherein the distribution management information transmission process, when the distribution management information includes location information of the consumer terminal, includes the distance between the consumer terminal and the distribution station in the distribution management information based on the location information and installation location information of the distribution station.

[0041] According to the sixteenth feature of the invention, by utilizing location information from the consumer's device in the distribution management information transmission process and including information on the distance to the nearest distribution station, consumers can easily identify the distribution station closest to their current location and efficiently obtain aquatic organisms. This reduces unnecessary travel and improves purchasing convenience, and shortens transportation time, allowing aquatic organisms to be delivered quickly while maintaining their freshness. Furthermore, distributors can optimize their distribution strategies taking into account consumer purchasing behavior, leading to improved efficiency in the overall distribution system and increased sales opportunities.

[0042] According to the first to fifth features of the present invention, it is possible to provide a denitrification filter medium that maintains its shape and is digested only when denitrifying bacteria feed on it. Furthermore, according to the sixth to tenth features of the present invention, it is possible to efficiently and stably denitrify the water to be treated in the entire denitrification tank under aerobic conditions. Furthermore, according to the eleventh to sixteenth features of the present invention, it is possible to deliver aquatic organisms to consumers while providing them with sufficient umami and preventing the generation of odors.

[0043] FIG. 1 is an explanatory diagram showing the cleaning process performed by a water purification device. FIG. 2 is an explanatory diagram showing the cleaning process performed by a water purification device. FIG. 3 is an explanatory diagram showing the purification process performed by a water purification device. FIG. 4 is an explanatory diagram showing the state of a denitrification filter medium (nitrification filter medium) in a modified water purification device. FIG. 5 is an explanatory diagram showing the state of a denitrification filter medium (nitrification filter medium) in a modified water purification device. FIG. 6 is an explanatory diagram showing the state of a denitrification filter medium (nitrification filter medium) in a modified water purification device. FIG. 7 is an explanatory diagram showing the purification process performed by a water purification device. FIG. 8 is a block diagram of an aquatic organism distribution management system. FIG. 9 is an explanatory diagram showing the layout of distribution stations on a consumer terminal. FIG. 10 is an explanatory diagram showing the inventory status of an aquatic organism at a specific distribution station on a consumer terminal. FIG. 11 is an explanatory diagram showing the inventory status of a specific aquatic organism at all distribution stations on a consumer terminal. FIG. 12 is a flowchart of a distribution management program.

[0044] First, although the following disclosure, diagrams, and / or claims may be described as being presented alone or in combination with one or more other aspects, the subject matter of the immediate disclosure is not intended to be so limited. That is, the immediate disclosure, diagrams, and claims are intended to encompass the various aspects described herein, each alone or in one or more combinations with each other. For example, even if the immediate disclosure describes and illustrates a first embodiment, a second embodiment, and a third embodiment in such a way that the first embodiment is described and illustrated specifically in conjunction with the second embodiment, or the second embodiment is described and illustrated only in conjunction with the third embodiment, the immediate disclosure and illustrations are not so limited and may include only the first embodiment, only the second embodiment, only the third embodiment, or one or more combinations of the first, second, and / or third embodiments, such as the first and second embodiments, the first and third embodiments, the second and third embodiments, or the first, second, and third embodiments.

[0045] The use of the phrase "or" herein shall mean a "non-exclusive" arrangement unless expressly specified otherwise. For example, when we say "item x is A or B," we mean either: (1) item x is either A or B, but not both; or (2) item x is both A and B. In other words, the word "or" is not used to define an "exclusive" arrangement.

[0046] Additionally, as used herein, the phrases "comprise at least one of" and "comprise at least one of the following," when used in connection with a system or element, mean that the system or element includes one or more of the elements listed after the phrase. For example, if there are three types of elements, a first element, a second element, or a third element, the phrases "comprise at least one of" and "comprise at least one of the following" are to be interpreted as any of the following structural arrangements: a device including the first element, a device including the second element, a device including the third element, a device including the first and second elements, a device including the first and third elements, a device including the second and third elements, or a device including the first, second, and third elements.

[0047] A similar interpretation is intended when the phrase "used in at least one of the following" is used herein. Furthermore, as used herein, "and / or" is used as a verbal conjunction to indicate that one or more of the listed elements or conditions are included or occur. For example, a device including a first element, a second element, and / or a third element is to be interpreted as any of the following structural arrangements: a device including the first element, a device including the second element, a device including the third element, a device including the first element and the second element, a device including the first element and the third element, a device including the second element and the third element, or a device including the first element, the second element, and the third element.

[0048] In addition, the use of the phrase "and / or" in the text means a "non-exclusive" agreement, as stipulated in the Japanese Industrial Standards (JIS) "Format and preparation method of standard sheets JIS Z 8301."

[0049] An example of a preferred embodiment for carrying out the present invention will be described below. Note that this is merely an example, and the technical scope of the present invention is not limited to this. That is, specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiment in any way, and can be carried out with appropriate modifications within the scope of the object of the present invention.

[0050] <Denitrification filter medium> The denitrification filter medium is composed of a biodegradable melt-kneaded resin composition containing (A) a water-insoluble and / or seawater-insoluble resin component that is biodegradable, and (B) a biomass polysaccharide polymer component.

[0051] [(A) Water-insoluble and / or sea-soluble resin component that is biodegradable] The (A) biodegradable resin component is not particularly limited as long as it is a water-insoluble and / or sea-soluble resin that is biodegradable.

[0052] Biodegradability means that the hydrolyzed resin is hydrolyzed by an enzyme contained in a certain microorganism, and the microorganism consumes the hydrolyzed resin as food, breaking it down into water and carbon dioxide. Component (A) of the present invention is a resin that is insoluble in water and / or seawater and is biodegradable by microorganisms that live in water and / or seawater.

[0053] Among biodegradable resins, those made from biomass as a raw material include polylactic acid, polycaprolactone, polyhydroxyalkanoate (microbially produced polyester), polybutylene succinate, polybutylene succinate adipate, polyglycolic acid, casein, and low-substituted polysaccharide derivatives (such as low-substituted cellulose acetate).

[0054] Component (A) is preferably an ester-bonded polymer. Even if the resin component is water-insoluble and / or seawater-insoluble, it is decomposed into harmless and non-toxic compounds by simple hydrolysis of the ester main chain in the body of the denitrifying bacteria. Therefore, the shape of the denitrifying filter medium does not collapse until the denitrifying bacteria feed on the biomass polysaccharide polymer component, and water pollution caused by the resin component can be prevented.

[0055] Polyvinyl alcohols are sometimes classified as biodegradable. However, polyvinyl alcohols are water-soluble and / or sea-soluble, and are not preferred in the present invention because they dissolve in water or seawater and cause foaming.

[0056] When the application is marine organism aquaculture, the treated water supplied to the denitrification device is seawater. In this case, the (A) biodegradable resin component must be marine biodegradable. Examples of marine biodegradable resins include polyhydroxyalkanoate, polybutylene succinate adipate, and polycaprolactone. Polyhydroxyalkanoate refers to a polymer containing hydroxyalkanoate (hydroxyalkanoic acid) as a monomer component.

[0057] Specific examples of polyhydroxyalkanoates (PHAs) include one or more selected from the group consisting of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVH), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHBB).

[0058] Other resins known to be degradable by marine microorganisms include PCL (polycaprolactone) and PBSA (polybutylene succinate adipate). PBSA is a polymer formed by ester bonds between 1,4 butanediol, succinic acid, and adipic acid. PCL is a polymer formed by ring-opening polymerization of petroleum-derived ε-caprolactone. PHA, PBSA, and PCL all have molecular structures in which monomers are linked by ester bonds.

[0059] [(B) Biomass Polysaccharide Polymer Component] Component (B) functions as a plant-derived filler and plays the role of a bulking agent. The biomass component refers to a resource derived from living organisms, and is a resource obtained from a variety of sources, such as forest thinnings, livestock excrement, and food waste.

[0060] The biomass component used as component (B) preferably has a helical molecular structure. Examples of biomass components having a helical molecular structure include starch and / or modified starch. When component (B) has a helical molecular structure, it can be included in the composition at a relatively higher ratio than biomass components that do not have a helical molecular structure, allowing the ratio of biomass components to be increased and the feed components to be highly concentrated. As a result, the frequency of supplying denitrification filter media can be reduced, and the burden on the manager of the denitrification device can be reduced.

[0061] Although biomass polysaccharide polymer components that do not have a helical molecular structure, such as cellulose, can be used as plant-derived fillers, there are limitations when kneading them with a high proportion of biomass components and a low content of biodegradable resin. However, even in these cases, kneading at high concentrations becomes possible if starch, which has a helical molecular structure, is coexistent.

[0062] Of starch, 20-25% is amylose and 75-80% is amylopectin.

[0063] Amylose has a structure similar to that of maltose (malt sugar), in which numerous α-glucose units are dehydrated and condensed between the hydroxyl groups (-OH) at the 1st and 4th positions (α-1,4-glycosidic bond). This structure is actually a linear helical structure, as it is bent like maltose. The -OH groups within the molecule are used for intramolecular hydrogen bonds that reinforce the helical structure. The linear polymerized portion of α-glucose molecules forms a helical structure of approximately one turn with six α-glucose residues due to hydrogen bonds. Furthermore, the helical structures are arranged parallel to each other via hydrogen bonds, forming a crystalline structure. The molecules can form crystals in a double helix state or a single helix state. First of all, there are three types of double-helical crystals: those in which the hydroxyl groups on each glucose residue form direct hydrogen bonds (Type A, derived from grains such as cornstarch), those with a single water molecule sandwiched between them (Type B, derived from rhizomes and bulbs such as potatoes), and a mixed type of both (Type C, derived from roots).Single-helical crystals are called Type V, and in nature they exist as an inclusion complex in which the oil and fat components contained in starch granules are enclosed within the single helix of amylose.

[0064] Amylopectin has a structure in which many α-glucose units are dehydrated and condensed between the 1st and 4th -OH groups, and between the 1st and 6th -OH groups (α-1,4-glycosidic bond, α-1,6-glycosidic bond). Due to the presence of 1,4 and 1,6 bonds, amylopectin has a branched spiral structure, unlike amylose.

[0065] Cellulose is a linear polymer composed of D-glucose molecules linked by β-1,4-glycosidic bonds. These bonds are very strong, and specific enzymes (cellulases) are required to break them down. In contrast, starch is a branched polymer composed of D-glucose molecules linked by α-1,4- and α-1,6-glycosidic bonds. This structure is relatively flexible, and many organisms can produce the enzymes that break down starch (amylases). For this reason, it is thought that starch is more susceptible to biodegradation by microorganisms, i.e., enzymatic hydrolysis and edible metabolism of the decomposition residue, than cellulose.

[0066] The starch may be any of those classified as waste biomass, unused biomass, or resource grains. The biomass material may also be derived from animals, such as eggshells.

[0067] The origin of the starch is not particularly limited, but may be derived from, for example, cassava, corn, potato, sweet potato, sago, tapioca, sorghum, beans, bracken, lotus, water chestnut, wheat, rice, oats, arrowroot, peas, etc. Specific examples include starches derived from corn or potato, and may also include high-amylose starches derived from corn or potato. One type of starch may be used, or two or more types may be used in combination. Furthermore, the starch may include modified starch, such as hydroxypropyl starch, etherified starch, esterified starch, cationized starch, or cross-linked starch.

[0068] The starch may be commercially available, typically ST Starch P (Nippon Starch Chemical Co., Ltd.), etc. Modified starch that has been subjected to chemical, physical, or biological treatment may also be used.

[0069] The average particle size of the primary particles of component (B) is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. If the average particle size of component (B) is large, the surface area of ​​the denitrification filter material is small, and it does not function effectively as food for denitrification bacteria, which may affect the denitrification ability of denitrification bacteria, so this is not preferred. The lower limit of the average particle size is not particularly limited, but in consideration of operability, it is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more.

[0070] In the present invention, the average particle size of the primary particles of component (B) is measured by a photographic imaging method. Specifically, the minor axis diameter and major axis diameter of each primary particle of component (B) are measured using image analysis software from a magnified image of an electron-stained molded sample taken with a transmission electron microscope (TEM), and the average is taken as the primary particle size of that component (B). Next, the volume of each component (B) is calculated by approximating it to a sphere with the calculated primary particle size, and the volume-average particle size is taken as the average primary particle size.

[0071] [Proportion of (A) component and (B) component] The lower limit of the content of the (B) component is not particularly limited as long as it is within a range that can achieve both sufficient strength for use as a denitrification filter material and cost reduction. The lower limit of the content of the (B) component is preferably 100 parts by mass or more per 100 parts by mass of the (A) component. In consideration of the denitrification effect, the upper limit of the content of the (B) component is more preferably 150 parts by mass or more, particularly preferably 200 parts by mass or more, per 100 parts by mass of the (A) resin component.

[0072] From the viewpoint of whether melt-kneading is possible, the upper limit of the content of the (B) component is preferably 700 parts by mass or less, more preferably 550 parts by mass or less, and even more preferably 400 parts by mass or less, per 100 parts by mass of the (A) resin component.

[0073] [Additives] The biodegradable resin composition of the present embodiment may contain various additives within the range that does not impair the effects described in the present embodiment. Examples of additives that can be used depending on the purpose include lubricants, crystallization nucleating agents, plasticizers, hydrolysis inhibitors, antioxidants, release agents, ultraviolet absorbers, colorants such as dyes and pigments, and inorganic fillers. However, it is preferable that these additives are derived from biomass.

[0074] [Lubricant] The type of lubricant is not particularly limited. Examples thereof include hydrogenated vegetable oils and fats, fatty acid amides such as behenic acid amide, stearic acid amide, erucic acid amide, and oleic acid amide, alkylene fatty acid amides such as methylene bis-stearic acid amide and ethylene bis-stearic acid amide, polyethylene wax, oxidized polyester wax, glycerin mono-fatty acid esters such as glycerin monostearate, glycerin monobehenate, and glycerin monolaurate, organic acid monoglycerides such as succinic acid saturated fatty acid monoglycerides, sorbitan fatty acid esters such as sorbitan behenate, sorbitan stearate, and sorbitan laurate, polyglycerin fatty acid esters such as diglycerin stearate, diglycerin laurate, tetraglycerin stearate, tetraglycerin laurate, decaglycerin stearate, and decaglycerin laurate, and higher alcohol fatty acid esters such as stearyl stearate. These may be used alone or in combination of two or more.

[0075] [Crystallization Nucleating Agent] The type of crystallization nucleating agent is not particularly limited as long as it can promote the crystallization of the resin component (A). For example, inorganic substances such as boron nitride, titanium oxide, talc, layered silicates, calcium carbonate, sodium chloride, and metal phosphates, sugar alcohol compounds derived from natural products such as erythritol, galactitol, mannitol, and arabitol, pentaerythritol, polyvinyl alcohol, chitin, chitosan, polyethylene oxide, aliphatic carboxylic acid amides, aliphatic carboxylic acid salts, aliphatic alcohols, aliphatic carboxylic acid esters, dimethyl adipate, dibutyl adipate, diisodecyl adipate, and dibutyl sebacate can be used. Examples of such compounds include dicarboxylic acid derivatives, cyclic compounds having C═O and a functional group selected from NH, S, and O in the molecule, such as indigo, quinacridone, and quinacridone magenta, sorbitol derivatives such as sorbitol, bisbenzylidene sorbitol, and bis(p-methylbenzylidene)sorbitol, compounds containing a nitrogen-containing heteroaromatic nucleus, such as pyridine, triazine, and imidazole, phosphate ester compounds, bisamides of higher fatty acids and metal salts of higher fatty acids, branched polylactic acid, and low-molecular-weight poly(3-hydroxybutyric acid). These compounds may be used alone or in combination of two or more.

[0076] [Plasticizer] The type of plasticizer is not particularly limited. Examples include modified glycerin compounds such as glycerin, glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate; adipate compounds such as diethylhexyl adipate, dioctyl adipate, and diisononyl adipate; polyether ester compounds such as polyethylene glycol dibenzoate, polyethylene glycol dicaprylate, and polyethylene glycol diisostearate; benzoate compounds such as benzyl 2(2-methoxyethoxy)ethyl adipate; epoxidized soybean oil, epoxidized fatty acid 2-ethylhexyl; and sebacic acid monoesters. These may be used alone or in combination of two or more.

[0077] [Method for manufacturing denitrification filter media] The denitrification filter media is composed of a biodegradable melt-kneaded resin composition. Because the denitrification filter media is made from a biodegradable melt-kneaded resin composition containing a water-insoluble and / or seawater-insoluble resin component, the biomass polysaccharide polymer component contained in the denitrification filter media can be solidified with the resin component, and the shape of the denitrification filter media does not collapse until the denitrification bacteria feed on it. In addition, unlike when the resin component is water-soluble, it does not foam in the aquarium. Furthermore, because the resin component is biodegradable, it can be completely digested by the denitrification bacteria, and the resin component does not cause water pollution.

[0078] Furthermore, biodegradation begins preferentially in the biomass polysaccharide polymer components on the surface of the lumps or inside the voids of the melt-kneaded resin composition, allowing aerobic conditions to be maintained even inside the lumps, with aerobic denitrifying bacteria prevailing over sulfate-reducing bacteria, reducing the risk of hydrogen sulfide generation.

[0079] The method for producing the denitrification filter medium is not particularly limited, and for example, it is sufficient to produce pellets in which component (B) is dispersed in component (A) at a high concentration.

[0080] <Water Purification Apparatus> The form of the water purification apparatus is not particularly limited, and it may be any apparatus that includes a denitrification tank to which the water to be treated is supplied, the above-mentioned denitrification filter material that is housed in the denitrification tank and on which aerobic denitrifying bacteria that reduce nitrate nitrogen in the water to be treated are settled, and an air supply mechanism that supplies air to the water to be treated.

[0081] The present invention will be specifically explained below with reference to test examples, but the present invention is not limited to these.

[0082] <<Test Example 1>>

[0083] <Production of Denitrification Filter Media> The (A) resin component and the (B) biomass component were previously dried in a hot air dryer (80 to 100°C, 12 hours), and the moisture content was checked and adjusted when weighed. Then, the components were thoroughly mixed in a plastic bag in the proportions of the (A) and (B) components shown in Table 1. The mixture was then extruded in a twin-screw extruder kneader (manufactured by Ikegai Corporation, PCM30) at a set temperature of 180°C and a rotation speed of 100 rpm, and cut to obtain kneaded composition pellets.

[0084] The raw materials are as follows: (A) component: polybutylene succinate adipate (product name: BioPBS / FD92PM, Mitsubishi Chemical Corporation) (B) component: potato starch (product name: ST Starch P, Nippon Starch Chemical Co., Ltd., average primary particle size: approximately 35 μm) Cellulose (Comparative Example 1, average fiber length: 45 μm, average fiber thickness: 35 μm) Cellulose (Comparative Example 2, product name: Viscopal P, Rengo Co., Ltd.)

[0085] [Evaluation] Flounder rearing experiment A 150 L biological filtration tank was installed for 500 L of rearing water, and flounders were reared at a stocking density of 1%. During this time, the change in nitrate nitrogen concentration was measured and the denitrification capacity was calculated.

[0086] In the present invention, the denitrification capacity is determined as follows.

[0087] The rearing water was sampled every 24 hours and the nitrate nitrogen concentration in the rearing water was measured. This process was repeated for three days. The average value of the measurement results was used as the denitrification capacity. The nitrate nitrogen concentration was measured using the cadmium reduction method, and in this test, a portable water quality measurement spectrophotometer DR900 (manufactured by HACH) was used.

[0088] The results of measuring the nitrate nitrogen concentration showed that Example 1 had a denitrification capacity of 300 mg / L / day. This means that 1 L of denitrification material can decompose and remove 300 mg of nitrate nitrogen per day. Example 2 had a denitrification capacity of 270 mg / L / day, and Example 3 had a denitrification capacity of 200 mg / L / day.

[0089] Cellulose is a linear polymer composed of D-glucose molecules linked by β-1,4-glycosidic bonds. These bonds are very strong, and specific enzymes (cellulases) are required to decompose them. In contrast, starch is a branched polymer composed of D-glucose molecules linked by α-1,4- and α-1,6-glycosidic bonds. This structure is relatively flexible, and many organisms can produce the enzymes that break down starch (amylases). For this reason, it is believed that biodegradation by microorganisms, i.e., enzymatic hydrolysis and edible metabolism of the decomposition residue, was more likely in Examples 1 and 2 than in Example 3.

[0090] In addition, in all of Examples 1 to 3, no foaming was observed in the water tank.

[0091] In closed circulation breeding systems, a protein skimmer (a foam separator) is often used in combination. This is a device that uses bubbles to float and separate impurities from the water, but if too much foam is produced, it can cause problems by discharging a lot of the breeding water outside. For this reason, it was previously necessary to turn off the protein skimmer after adding denitrification material.

[0092] In Examples 1 to 3, there is no foaming, so the protein skimmer can be left on continuously even after the denitrification material is added, which is preferable.

[0093] On the other hand, in Comparative Example 1, not only was the denitrification capacity limited to 150 mg / L / day, but intense foaming was observed in the tank. It is presumed that the intense foaming in the tank was caused by the fact that the polyvinyl alcohol resin component is water-soluble. In Comparative Example 1, as in the past, it was necessary to turn off the protein skimmer after adding the denitrification material.

[0094] Furthermore, if there are a lot of bubbles on the water surface, it becomes difficult to see underwater, which can be a hindrance when monitoring with a camera.

[0095] In addition, in Comparative Example 1, jelly-like lumps formed and adhered to multiple locations within the device, making it look unsightly. This is presumably due to the reaction between the PVA and some component, such as oil, contained in the feed, forming the jelly-like lumps.

[0096] In Comparative Example 2, not only was the denitrification capacity limited to 150 mg / L / day, but foaming was observed in the tank, and as with conventional methods, the protein skimmer had to be turned off after adding the denitrification material. This is presumably because the shape of the denitrification filter material was distorted, and the pulverized cellulose was dispersed into the treated water even though it was not used as food by the denitrification bacteria, resulting in contamination of the treated water.

[0097] (Water Purification Apparatus 100) Next, a description will be given of a water purification apparatus 100 using the above-mentioned denitrification filter medium. Note that the water purification apparatus 100 may use a denitrification filter medium other than the above-mentioned denitrification filter medium.

[0098] The water purification device 100 is configured so that an entrapment filter material that double-encapsulates nitrifying microorganisms and denitrifying microorganisms is placed in a reaction tank, and then sewage (substrate aqueous solution) is supplied into the reaction tank, passed through the entrapment filter material, and discharged out of the reaction tank.The oxygen necessary for nitrification is also sent from a blower through an air diffuser into the reaction tank.When oxygen contained in the air is supplied to the nitrifying microorganisms and denitrifying microorganisms, depending on the amount of oxygen supplied, the efficiency of the nitrification and denitrification reactions for the sewage (substrate aqueous solution) throughout the reaction tank may be insufficient.Therefore, the water purification device 100 is configured so that denitrification of the water to be treated, such as sewage, can be efficiently and stably performed throughout the entire reaction tank under aerobic conditions.

[0099] An example of a preferred embodiment for carrying out the present invention will be described below. Note that this is merely an example, and the technical scope of the present invention is not limited to this. That is, in the following description, water for raising aquatic organisms is used as an example of water to be treated, but the water is not limited to this and may be any water that requires purification, as will be described in detail later.

[0100] (Overview of the Water Purification Apparatus 100) As shown in FIG. 1 , the water purification apparatus 100 is configured to supply air from the bottom of the denitrification tank 11 at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, and to perform a denitrification reaction using the suspended air bubbles 7. This allows the water purification apparatus 100 to perform a denitrification reaction in the water to be treated using oxygen in the air rather than dissolved oxygen in the water. As a result, while the amount of dissolved oxygen in natural water is at most about 10 mg (10 ppm), the weight of oxygen in 1 liter of air is 258 mg. Therefore, the water purification apparatus 100, which performs a denitrification reaction using the abundant oxygen in the air rather than dissolved oxygen, can efficiently and stably perform denitrification of the water to be treated throughout the entire denitrification tank 11 under aerobic conditions.

[0101] Here, "denitrification" refers to the reaction in which nitrate nitrogen and nitrite nitrogen are reduced to nitrogen gas by the action of denitrifying bacteria. Denitrification under aerobic conditions is a reaction that uses oxygen as an electron donor, and is carried out under conditions of high oxygen concentration by aerobic bacteria. ３－ " and "nitrite nitrogen (NO ２－ ) are nitrogen compounds with different oxidation states of nitrogen, and are intermediate products before being reduced to nitrogen gas by denitrifying bacteria in the denitrification reaction.

[0102] "Aerobic bacteria" is a general term for bacteria that grow in the presence of oxygen, and representative examples include denitrifying bacteria and nitrate-reducing bacteria. "Denitrifying bacteria" is a general term for bacteria that have the ability to reduce nitrate nitrogen and nitrite nitrogen to nitrogen gas, and representative examples include Paracoccus denitrificans, Pseudomonas stzerzeri, and Thiobacillus denitrificans. "Nitrate-reducing bacteria" is a general term for bacteria that have the ability to reduce nitrate nitrogen to nitrogen gas, and representative examples include Paracoccus pantotrophus, Pseudomonas aureofaciens, and Thiobacillus denitrificans.

[0103] Examples of "water to be treated" include sewage, livestock wastewater, agricultural wastewater, industrial wastewater, seawater, and water used to raise aquatic organisms. "Aquatic organisms" refer to organisms that live in water or near water, such as fish and shellfish, shrimp, and crabs. Note that "water" and "water used to raise aquatic organisms" here refer to either seawater or freshwater, and are not limited to one or the other.

[0104] The reason for supplying air at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated is to enable the denitrification reaction to occur in the water to be treated using oxygen in the air rather than dissolved oxygen in the water. The reason for the lower limit of the numerical range being 50% is that if the value is less than 50%, the denitrification process will be carried out using dissolved oxygen in the water, resulting in a drastic decrease in processing capacity. On the other hand, the reason for the upper limit of the numerical range being 5000% is that if the value exceeds 5000%, the disadvantages of increased damage to the filter media and increased power consumption will outweigh the benefits of increased nitriding processing capacity. Furthermore, when air is supplied from the bottom of the denitrification tank 11 at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, the water to be treated and the denitrification filter media 61 stored in the denitrification tank 11 are stirred throughout the entire tank by the upward flow of air, and the denitrification reaction will occur evenly throughout the entire tank. Specifically, it was experimentally confirmed that the efficiency of the denitrification reaction improves when air is supplied from the bottom of the denitrification tank 11 at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated. Details will be explained in the Examples and Comparative Examples below. The reason why the nitrification reaction occurs due to the air bubbles 7 when air is supplied at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated is the same.

[0105] (Specific example of water purification device 100) As a specific example of the water purification device 100, the water purification device 100 has a denitrification device 1 that denitrifies nitrate nitrogen and nitrite nitrogen in the breeding water stored in a breeding tank 8 used to breed aquatic organisms, using denitrifying bacteria under aerobic conditions, and a nitrification device 2 that nitrifies ammonia nitrogen in the breeding water using nitrifying bacteria under aerobic conditions. The nitrification device 2 will be described later.

[0106] (Denitrification apparatus 1: denitrification tank 11) The denitrification apparatus 1 has a denitrification tank 11 to which breeding water stored in a breeding aquarium 8 used for breeding aquatic organisms is supplied. The denitrification tank 11 is formed in a cylindrical shape with an open top. The opening of the denitrification tank 11 allows nitrogen gas generated in the denitrification reaction to escape to the outside, thereby preventing nitrogen gas from filling the denitrification tank 11. Breeding water from the breeding aquarium 8 is supplied to the denitrification tank 11 from above via a first breeding water supply path 12. The first rearing water supply path 12 has a rearing water supply pump 124 connected to the bottom of the rearing aquarium 8, a rearing water supply pipe 121 that guides the rearing water to the denitrification tank 11 and the nitrification tank 21, a first supply valve 122 that can switch between supplying and stopping the supply of rearing water to the denitrification tank 11, and a second supply valve 123 that can switch between supplying and stopping the supply of rearing water to the nitrification tank 21 of the nitrification device 2.

[0107] The denitrification tank 11 is also connected to a first breeding water recovery conduit 14 that delivers denitrified breeding water to the breeding tank 8. The first breeding water recovery conduit 14 has a breeding water supply pump 142 connected to the bottom of the denitrification tank 11 and a breeding water supply pipe 141 that guides the breeding water to the breeding tank 8. The amount of breeding water supplied from the breeding tank 8 and the amount of breeding water delivered to the breeding tank 8 are controlled so that the liquid level of the breeding water matches a predetermined first reference height. That is, the liquid level of the breeding water is controlled to match the first reference height by a combination of adjusting the delivery rates of the breeding water supply pump 124 and the breeding water supply pump 142 and switching the first supply valve 122 on and off. This allows the denitrification tank 11 to circulate the breeding water between the breeding tank 8 and the denitrification tank 11 intermittently at predetermined intervals or continuously, depending on the status of the denitrification treatment and the breeding status of the aquatic organisms in the breeding tank 8. The denitrification tank 11 is capable of carrying out denitrification treatment while storing a fixed amount of rearing water, whether in an intermittent circulation mode or a continuous circulation mode.

[0108] The liquid level of the rearing water is detected by a level gauge 15 provided in the denitrification tank 11. Examples of the liquid level gauge 15 include a float level gauge in which a float ball or a flotation device floats on the surface of the rearing water and detects the liquid level in conjunction with a pointer that indicates its position, a conductive level gauge that detects the liquid level by utilizing the conductivity of the rearing water, an ultrasonic level gauge that uses ultrasound to measure the distance to the surface of the rearing water to detect the liquid level, and a radar level gauge that detects the liquid level by using microwaves or radar signals.

[0109] (Denitrification Device 1: Denitrification Filter Media 61) The denitrification tank 11 contains a denitrification filter media 61 for the establishment of aerobic denitrification bacteria that reduce nitrate nitrogen in the rearing water. The denitrification filter media 61 has a porous structure that facilitates the establishment of denitrification bacteria. Examples of denitrification filter media 61 include circular porous polyethylene filter media, rectangular porous ceramic filter media, bead-shaped porous activated carbon filter media, sponge-shaped porous polyurethane filter media, nonwoven porous polyester filter media, and paper-shaped porous cellulose filter media. The denitrification filter media 61 preferably contains organic matter such as sugars, amino acids, lipids, and nucleic acids. This is because these organic matter provide the energy source necessary for the growth of denitrification bacteria. The denitrification filter media 61 also preferably contains trace elements such as phosphorus, sulfur, magnesium, and potassium. These trace elements are essential for the metabolism of denitrification bacteria, and a deficiency of these elements reduces the activity of denitrification bacteria. The denitrification filter medium 61 may also be made of a carbon donor (carrier) with a CnHnOn structure, such as a chain of sugars, such as cellulose or starch. In this case, the denitrification filter medium 61 formed using a carbon donor (carrier) containing sugars, such as cellulose or starch, is consumed by bacteria that perform denitrification under aerobic conditions, providing the energy necessary for bacterial growth and activity and functioning as an electron donor in the denitrification process. As the bacteria continue to consume the denitrification filter medium 61, it will eventually decompose and disappear.

[0110] The denitrification filter media 61 are formed to have a mass and size sufficient to float in the rearing water. As a result, the denitrification filter media 61 are agitated as the air bubbles 7 rise, so that the surface of the denitrification filter media 61 is constantly washed with water, and oxygen is distributed over the surface of the denitrification filter media 61, which activates the denitrification bacteria and increases the efficiency of nitrate nitrogen removal. Furthermore, agitating the denitrification filter media 61 in water disperses the stacked denitrification filter media 61, increasing the surface area of ​​the denitrification filter media 61 and increasing the amount of denitrification bacteria that can settle. Note that multiple denitrification filter media 61 may be contained in a mesh bag.

[0111] (Denitrification Apparatus 1: Denitrification Air Supply Mechanism 13) The denitrification tank 11 is further provided with a denitrification air supply mechanism 13 that supplies oxygen-containing air into the denitrification tank 11. The denitrification air supply mechanism 13 is configured to generate air bubbles 7 in the breeding water stored in the denitrification tank 11. The denitrification air supply mechanism 13 continuously performs an oxygen intake operation that exposes the denitrification filter medium 61 to the air in the air bubbles 7, thereby promoting a denitrification reaction by denitrifying bacteria under aerobic conditions. Specifically, when the air bubbles 7 come into contact with the denitrification filter medium 61 due to the oxygen intake operation, the oxygen in the air bubbles 7 diffuses to the surface of the denitrification filter medium 61. As a result, the surface of the denitrification filter medium 61 is saturated with oxygen, and the denitrification bacteria that have settled on the surface of the denitrification filter medium 61 use the oxygen to decompose nitrate nitrogen and nitrite nitrogen, promoting an aerobic denitrification reaction that produces nitrogen. The air supplied to the denitrification tank 11 may contain ozone gas in an amount that does not adversely affect aquatic organisms. The reason for this is that when aerobic denitrification is performed using aerobic denitrifying bacteria, the rearing water may turn brown, and ozone can be used to remove this coloration. Furthermore, the strong oxidizing power of ozone can sterilize microorganisms such as bacteria and viruses, thereby maintaining good hygiene in the rearing water.

[0112] The denitrification air supply mechanism 13 includes a blower 131 disposed outside the denitrification tank 11 and an air supply pipe 132 connected to the exhaust port of the blower 131 and disposed at the bottom of the denitrification tank 11. A plurality of through-holes 132a are formed in the side of the air supply pipe 132. The denitrification air supply mechanism 13 supplies air bubbles from the bottom of the denitrification tank 11 to the culture water by having the blower 131 send air into the air supply pipe 132 and then expel the air through the through-holes 132a. The denitrification air supply mechanism 13 preferably includes a throttle mechanism, such as a diaphragm valve, that can change the diameter of the through-holes 132a, allowing the diameter of the through-holes 132a to be increased or decreased depending on the amount of air supplied. In this case, the average diameter of the floating air bubbles 7 can be adjusted by adjusting the amount of air supplied and the diameter of the through-holes 132a.

[0113] The air supply pipe 132 is arranged over the entire bottom surface of the denitrification tank 11 and is configured to supply air in the form of bubbles from the entire bottom surface of the denitrification tank 11. As a result, the denitrification air supply mechanism 13 supplies air from the entire bottom surface of the denitrification tank 11, thereby enabling air to be supplied evenly throughout the breeding water in the denitrification tank 11 and circulating and agitating the breeding water throughout the denitrification tank 11.

[0114] (Denitrification Apparatus 1: Other Configurations) The denitrification tank 11 is preferably provided with a band heater and cooling piping (not shown) along with a temperature detector for detecting the temperature of the rearing water. In this case, even in seasons when the atmospheric temperature rises and falls significantly from room temperature, the temperature of the rearing water in the denitrification tank 11 can be detected by the temperature detector and the power supply to the band heater and the amount of water to the cooling piping can be adjusted to maintain a constant temperature while performing denitrification. The denitrification tank 11 is preferably provided with a foam separation device (protein skimmer). The foam separation device is a device for removing organic matter and proteins from the rearing water. As air bubbles 7 rise in the rearing water, the foam separation device adsorbs highly hydrophobic organic matter and proteins onto the air bubbles 7, thereby removing the organic matter and proteins that rise to the water surface.

[0115] (Nitrification device 2: nitrification tank 21) The water purification system 100 equipped with the denitrification device 1 configured as described above further includes a nitrification device 2 that nitrifies ammonia nitrogen in the breeding water using nitrifying bacteria under aerobic conditions. The nitrification tank 21 has the same configuration as the denitrification tank 11 of the denitrification device 1, and therefore a description thereof will be omitted. Here, "ammonia nitrogen" is a form of nitrogen that exists mainly in the form of ammonia and ammonium ions, and is produced by the decomposition of metabolic products of aquatic organisms and organic matter, and is efficiently converted into nitrite nitrogen and then nitrate nitrogen through nitrification by nitrifying bacteria.

[0116] The nitrification tank 21 is connected to the breeding aquarium 8 via a breeding water supply pipe 121 and a second supply valve 123. The breeding water supply pipe 121 supplies breeding water drawn from the breeding aquarium 8 by a breeding water supply pump 124 from above the nitrification tank 21. A second breeding water recovery line 25, which delivers nitrified breeding water to the breeding aquarium 8, is also connected to the nitrification tank 21. The second breeding water recovery line 25 includes a breeding water supply pump 252 connected to the bottom of the nitrification tank 21 and a breeding water supply pipe 251 that guides the breeding water to the breeding aquarium 8. The amount of breeding water supplied from the breeding aquarium 8 and the amount of breeding water supplied to the breeding aquarium 8 are controlled so that the level of the breeding water coincides with a predetermined second reference height. That is, the level of the breeding water is controlled so as to coincide with the second reference height by switching the second supply valve 123 on and off.

[0117] This allows the nitrification tank 21 to circulate the rearing water between the rearing tank 8 and the nitrification tank 21 either intermittently at predetermined intervals or continuously, depending on the status of the nitrification reaction and the rearing status of the aquatic organisms in the rearing tank 8. The nitrification tank 21 is capable of carrying out nitrification treatment with a fixed amount of rearing water stored in it, whether in the intermittent or continuous circulation mode. The level of the rearing water is detected by a level gauge 28 provided in the nitrification tank 21. Note that the level gauge 28 is the same as the level gauge 15 in the denitrification tank 11, and therefore a description thereof will be omitted.

[0118] (Nitrification Tank 21: Nitrification Air Supply Mechanism 24) The nitrification tank 21 is further provided with a nitrification air supply mechanism 24 that supplies oxygen-containing gaseous air into the nitrification tank 21. The nitrification air supply mechanism 24 is configured to generate air bubbles 7 in the breeding water stored in the nitrification tank 21. The nitrification air supply mechanism 24 continuously performs an oxygen intake operation that exposes the nitrification filter medium 62 to the air in the air bubbles 7, thereby promoting the nitrification reaction by nitrifying bacteria under aerobic conditions. Specifically, when the air bubbles 7 come into contact with the nitrification filter medium 62 due to the oxygen intake operation, the oxygen in the air bubbles 7 diffuses to the surface of the nitrification filter medium 62. As a result, the surface of the nitrification filter medium 62 is saturated with oxygen, and the nitrifying bacteria that have settled on the surface of the nitrification filter medium 62 use the oxygen to decompose ammonia nitrogen, promoting the aerobic nitrification reaction that produces nitrogen.

[0119] Here, "nitrifying bacteria" is a general term for bacteria that oxidize ammonia nitrogen, such as ammonia and amines, to nitrite ions and then nitrate ions. "Nitrification reaction" is the reaction in which ammonia nitrogen is oxidized to nitrite nitrogen and then nitrate nitrogen.

[0120] The nitrification air supply mechanism 24 includes a blower 241 located outside the nitrification tank 21 and an air supply pipe 242 connected to the exhaust port of the blower 241 and located at the bottom of the nitrification tank 21. The air supply pipe 242 has a plurality of through-holes 242a formed on its side. The nitrification air supply mechanism 24 supplies air bubbles from the bottom of the nitrification tank 21 by having the blower 241 send air into the air supply pipe 242 and then expelling the air through the through-holes 242a. Similar to the denitrification air supply mechanism 13, the nitrification air supply mechanism 24 preferably includes a throttle mechanism such as a diaphragm valve that can change the diameter of the through-holes 242a. The air supply pipe 242 is located across the entire bottom surface of the nitrification tank 21, allowing air bubbles to be supplied from the entire bottom surface of the nitrification tank 21. As a result, the nitrification air supply mechanism 24 supplies air from the entire bottom surface of the nitrification tank 21, thereby evenly supplying air to the entire rearing water in the nitrification tank 21 and enabling the rearing water to be circulated and stirred throughout the entire nitrification tank 21.

[0121] (Nitrification Tank 21: Other Configurations) The nitrification tank 21 is preferably provided with a band heater and cooling piping (not shown) along with a temperature detector for detecting the temperature of the rearing water. In this case, even in seasons when the atmospheric temperature rises and falls significantly from room temperature, the temperature of the rearing water in the nitrification tank 21 can be detected by the temperature detector and the power supply to the band heater and the amount of water to the cooling piping can be adjusted to maintain a constant temperature while performing nitrification treatment. The nitrification tank 21 is preferably provided with a foam separation device (protein skimmer).

[0122] (Rearing Control Device 3) The processing operations of the denitrification device 1 and the nitrification device 2 configured as described above are controlled by the rearing control device 3. The rearing control device 3 includes a denitrification control unit 31 that controls the denitrification device 1, a nitrification control unit 32 that controls the nitrification device 2, and a rearing aquarium control unit 33 that controls the water level, temperature, etc. of the rearing aquarium 8. The rearing control device 3 may be a personal computer, a programmable controller, or a combination of a personal computer and a programmable controller. In addition, the rearing control device 3 may include the denitrification control unit 31, the nitrification control unit 32, and the rearing aquarium control unit 33, each of which may be configured as a personal computer or a programmable controller. Furthermore, the rearing control device 3 may be connected to a monitoring device 4 operated by an administrator 52 so as to enable data communication. In this case, remote monitoring of the water purification device 100 is possible, and centralized monitoring of multiple water purification devices 100 installed at different locations is also possible.

[0123] (Variation 1) In the water purification device 100 described above, the denitrification tank 11 and the nitrification tank 21 are connected in parallel to the breeding aquarium 8 via the first breeding water supply path 12, and breeding water from the breeding aquarium 8 is supplied separately to the denitrification tank 11 and the nitrification tank 21, thereby independently carrying out denitrification and nitrification processes. However, the present invention is not limited to this configuration. As shown in Fig. 2, the water purification device 100 may also have the nitrification device 2 and the denitrification device 1 connected in series to the breeding aquarium 8. Specifically, the breeding water from the breeding aquarium 8 may be supplied to the nitrification tank 21 via the breeding water supply pump 222 and the breeding water supply pipe 221 of the second breeding water supply path 22, and the breeding water from the nitrification tank 21 may be supplied to the denitrification tank 11 via the breeding water supply pump 232 and the breeding water supply pipe 231 of the third breeding water supply path 23. According to this configuration, the nitrification treatment of the breeding water in the nitrification device 2 and the denitrification treatment of the breeding water in the denitrification device 1 are carried out continuously, and the water quality of the breeding water in the breeding tank 8 is purified.

[0124] Furthermore, in the water purification apparatus 100 (FIG. 1), the air supply pipes 132, 242 of the denitrification air supply mechanism 13 and the nitrification air supply mechanism 24 are arranged over the entire bottom surface of the denitrification tank 11 and the nitrification tank 21, respectively, so that air bubbles are supplied from the entire bottom surface of each tank 11, 21. However, this is not a limitation. Specifically, the air supply pipes 242, 132 may be arranged at the center of the bottom surface of each tank 11, 21, so that air bubbles are supplied from the center of the bottom surface of each tank 11, 21. This configuration generates a swirling flow that causes the culture water and air to rise from the center of the bottom surface of each tank 11, 21, swirl at the top, and then flow back down to the center of the bottom, thereby promoting agitation of the culture water and filter media 61, 62. In addition, either one of the denitrification air supply mechanism 13 or the nitrification air supply mechanism 24 may be configured to supply air bubbles 7 from the entire surface of FIG. 1, and the other may be configured to supply air bubbles 7 from the center of the bottom surface of FIG. 2.

[0125] The blowers 131 and 241 may also be configured to control the amount of air they supply. Supplying a constant amount of air can maintain a constant flow rate and direction of the rearing water. On the other hand, increasing or decreasing the amount of air supplied can change the flow rate and direction of the rearing water. Therefore, if the amount of air supplied by the blowers 131 and 241 is controllable, the swirling flow of the rearing water can be changed by changing the amount of air supplied, thereby promoting agitation of the rearing water in each tank 11 and 21.

[0126] Furthermore, in the water purification device 100 described above, the denitrification filter medium 61 and the nitrification filter medium 62 are placed in separate tanks, the denitrification tank 11 and the nitrification tank 21, where the nitrification and nitrification treatments are carried out, respectively. However, this is not limited to this, and the denitrification filter medium 61 and the nitrification filter medium 62 may be placed in a single treatment tank to carry out the nitrification and nitrification treatments of the breeding water. In other words, the water purification device 100 may carry out the nitrification and nitrification treatments of the breeding water in a state where the denitrification filter medium 61 and the nitrification filter medium 62 are mixed.

[0127] As shown in Figure 3, the water purification device 100 may include an air flow restriction member 101 disposed above the air supply pipe 132 (242) (air outlet) of the denitrification air supply mechanism 13 (nitrification air supply mechanism 24). The air flow restriction member 101 restricts the flow direction of the upward flow of air supplied from the air supply pipe 132 (242) to the rearing water (water to be treated) and concentrates it in one location, thereby circulating the rearing water and the denitrification filter material 61 (nitrification filter material 62) throughout the denitrification tank 11 (nitrification tank 21). That is, the water purification device 100 may include a cylindrical air flow restriction member 101 disposed underwater above the air supply pipe 132 (242) (air outlet) of the denitrification air supply mechanism 13 (nitrification air supply mechanism 24). The opening area expands from the upper opening to the lower opening, allowing the rearing water and the denitrification filter material 61 (nitrification filter material 62) to pass through.

[0128] Specifically, the air flow regulating member 101 is provided above the air supply pipe 132 (242). The air flow regulating member 101 is provided at a height where it is immersed in the rearing water. The air flow regulating member 101 is formed in a cylindrical shape with openings on the top and bottom, and is provided so that the central axis passing through the centers of the top and bottom faces is in the vertical direction. The air flow regulating member 101 is opposed to the top face of the air supply pipe 132 (242) so that the opening on the bottom faces covers the top face. This allows the air flow regulating member 101 to collect, within the air flow regulating member 101, air bubbles 7 that are discharged from the air supply pipe 132 (242) into the rearing water and rise.

[0129] The opening area of ​​the air flow restriction member 101 decreases from the bottom to the top. The air flow restriction member 101 may be a truncated cone with a circular top and a square bottom, a truncated hexagonal pyramid with a hexagonal top and an octagonal bottom, or a star-shaped cone with a star-shaped top and a circular bottom. This allows the air flow restriction member 101 to restrict the flow direction of the upward flow of air supplied from the air supply pipe 132 (242) to the rearing water (water to be treated) and concentrate it in one location. The opening on the top surface of the air flow restriction member 101 is sized to allow the denitrification filter material 61 (nitrification filter material 62) to pass through. The gap between the lower edge of the air flow restriction member 101 and the air supply pipe 132 (242) is sized to allow the denitrification filter material 61 (nitrification filter material 62) to pass through. As a result, the air flow control member 101 immersed in the breeding water discharges the air bubbles 7 rising from the air supply pipe 132 (242) together with the denitrification filter material 61 (nitrification filter material 62) from the opening on the top surface, thereby circulating the breeding water and the denitrification filter material 61 (nitrification filter material 62) throughout the denitrification tank 11 (nitrification tank 21).

[0130] According to the above configuration, the airflow restriction member 101 concentrates the airflow of the bubbles 7, increasing the density of the bubbles 7. This efficiently supplies air to the denitrification filter media 61 (nitrification filter media 62), accelerating the denitrification reaction (nitrification reaction), just as the denitrification reaction (nitrification reaction) of the denitrification filter media 61 (nitrification filter media 62) is carried out in the atmosphere. Furthermore, the same effect as the denitrification reaction (nitrification reaction) in the atmosphere can be continuously achieved in the rearing water circulating throughout the tank, thereby improving the denitrification efficiency (nitrification reaction). Furthermore, the concentration of the bubbles 7 also concentrates the denitrification filter media 61 (nitrification filter media 62) floating in the rearing water, increasing the opportunities for the denitrification filter media 61 (nitrification filter media 62) to come into contact with each other, effectively cleaning the surfaces of the denitrification filter media 61 (nitrification filter media 62). This improves the efficiency of the denitrification reaction and prevents early deterioration of the treatment performance of the denitrification filter media 61 (nitrification filter media 62).

[0131] The air flow regulating member 101 may be partially connected to the air supply pipe 132 (242) of the denitrification air supply mechanism 13 (24) and incorporated into the denitrification air supply mechanism 13 (24) as a unit. In this case, the blower 131 (241) and the air supply pipe 132 (242) are connected with a flexible hose, and the denitrification air supply mechanism 13 (24) is made detachable from the denitrification tank 11 (21), so that the denitrification air supply mechanism 13 (24) can be easily attached to an existing denitrification tank 11 (21).

[0132] Furthermore, the water purification device 100 may be installed underwater as a unit, as shown in FIG. 7 . Specifically, the water purification device 100 includes a filter media container 9 having an intermediate wall 94 between its upper and lower surfaces, with a plurality of through-holes 94a formed therein, and a communication section 92a on the upper wall surface of the intermediate wall 94 that communicates with the outside; and an air supply mechanism 96 disposed below the intermediate wall 94 in the filter media container 9 and spraying air as bubbles 7 into the breeding water (water to be treated). The filter media container 9 contains at least one of the filter media 61 and 62, supported by the intermediate wall 94, which are a denitrifying filter media 61 that colonizes aerobic denitrifying bacteria that reduce nitrate nitrogen in the breeding water and a nitrifying filter media 62 that colonizes aerobic nitrifying bacteria that oxidize ammonia nitrogen in the breeding water. The filter media container 9 may be configured such that the opening area is enlarged from the upper surface to the lower surface, concentrating the plurality of bubbles 7 as they rise.

[0133] With the above configuration, the water purification device 100 is made into a unit, which allows it to be easily applied to existing purification facilities such as the breeding aquarium 8 and a septic tank. That is, it can be set up by simply placing the water purification device 100 in the breeding aquarium 8. When air bubbles 7 are generated by the air supply mechanism 96, the air bubbles 7 rise and pass through the through-holes 94a, moving through the gaps between the filter media 61 and 62 and stirring the filter media 61 and 62, so that denitrification and nitrification treatments can be performed on the breeding water while raising fish, etc.

[0134] As shown in FIG. 4 , the denitrification filter medium 61 (nitrification filter medium 62) may be formed as a porous medium having a plurality of communication passages 611 (621) and fixed above the bubble 7 generation position, which is the installation position of the denitrification bubble generation mechanism 13 (nitrification air supply mechanism 24). For example, the filter medium 61 (62) may be formed as a block body, such as a rectangular parallelepiped, of a predetermined size and shape, having communication passages 611 (621) in the vertical direction (the direction in which the bubbles 7 rise). In this case, even if the horizontal size of each tank 11 (21) is large, by arranging multiple block bodies in parallel in the horizontal direction (the direction perpendicular to the direction in which the bubbles 7 rise), it is possible to cover the entire area above the air supply pipe 132 (242). Note that, when the vertical size of each tank 11 (21) is large, it is preferable to arrange multiple block bodies in multiple vertical tiers.

[0135] As shown in FIG. 5 , the denitrification filter medium 61 (nitrification filter medium 62) may have a communication passage 611 (621) with a flow area that decreases from the bottom to the top. In this case, when air bubbles 7 ascend through the communication passage 611 (621) of the filter medium 61 (62), the flow area of ​​the communication passage 611 (621) decreases from the bottom to the top, increasing the flow rate of the bubbles 7 as they ascend. Then, due to the parachute effect of hydrodynamics, the bubbles 7 deform into a parachute shape, increasing their surface area and their contact area with the wall of the communication passage 611 (621). This brings the bubbles 7 into closer contact with the wall of the communication passage 611 (621), increasing the interaction between the bubbles 7 and the wall, locally increasing the pressure on the wall. This increases the amount of oxygen available for use by denitrification bacteria and nitrification bacteria.

[0136] According to the above configuration, when bubbles 7 are generated, they pass through the communication passages 611 (621) of the filter medium 61 (62) as they rise in the rearing water. As the bubbles 7 flow along the communication passages 611 (621), they take on the average diameter of the communication passages 611 (621). This allows the denitrification reaction (nitrification reaction) to occur with the bubbles 7 in suspension whose average diameter is the average diameter of the communication passages 611 (621).

[0137] As shown in Figure 6, the filter material 61 (62) may be formed as a block, such as a sphere, having a mesh of connecting passages 611 (621) and a specific gravity greater than that of the breeding water. In this case, by submerging the filter material 61 (62) in the breeding water and allowing bubbles 7 to rise from below, some of the bubbles 7 move through the gaps between the filter material 61 (62), while the rest pass through the connecting passages 611 (621) of the filter material 61 (62) to form bubbles 7 with an average flow path diameter, allowing denitrification and nitrification treatments to be performed.

[0138] (Summary of the Water Purification Device 100) (1) As shown in Figures 1 and 2, the water purification device 100 includes a denitrification tank 11 to which breeding water stored in a breeding tank 8 used for breeding aquatic organisms is supplied, a denitrification filter medium 61 housed in the denitrification tank 11 and which settles aerobic denitrifying bacteria that reduce nitrate nitrogen in the breeding water, and a denitrification air supply mechanism 13 located at the bottom of the denitrification tank 11. The denitrification air supply mechanism 13 continuously performs an oxygen intake operation by supplying air to the breeding water stored in the denitrification tank 11 at a volumetric rate of 50% to 5000% per minute of the breeding water storage volume to expose the denitrification filter medium 61 to air, thereby promoting the denitrification reaction by the denitrifying bacteria under aerobic conditions.

[0139] According to the above configuration, air is supplied from the bottom of the denitrification tank 11 at a volumetric rate of 50% to 5,000% per minute of the total volume of the rearing water, thereby agitating the rearing water and the denitrification filter media 61 throughout the denitrification tank 11. The denitrification reaction is accelerated by continuously exposing the denitrification filter media 61 to air, thereby promoting the denitrification reaction. This enables efficient and stable denitrification of the rearing water for aquatic organisms throughout the denitrification tank 11 under aerobic conditions. Furthermore, microbial activity occurring during the denitrification process can also remove phosphorus through biological phosphorus removal (BPR), a phenomenon in which phosphorus is taken up into cells.

[0140] (2) As shown in FIG. 3 , the water purification device 100 has an air flow restriction member 101 that is disposed above the air discharge section (air supply pipe 132) of the denitrification air supply mechanism 13 and restricts the flow direction of the upward flow of air supplied from the air discharge section (air supply pipe 132) to the rearing water (water to be treated) and concentrates it in one location, thereby circulating the rearing water (water to be treated) and the denitrification filter media 61 throughout the denitrification tank 11.

[0141] According to the above configuration, the airflow restricting member 101 concentrates the airflow consisting of the bubbles 7, thereby increasing the density of the bubbles 7. This efficiently supplies air to the denitrification filter media 61, accelerating the denitrification reaction, just as if the denitrification reaction were carried out in the atmosphere. This same effect as the denitrification reaction in the atmosphere can be continuously achieved in the rearing water (water to be treated) circulating throughout the denitrification tank 11, thereby improving denitrification efficiency. Furthermore, the concentration of the bubbles 7 also concentrates the denitrification filter media 61 floating in the water to be treated, increasing the opportunities for the denitrification filter media 61 to come into contact with each other, effectively cleaning the surfaces of the denitrification filter media 61, improving the efficiency of the denitrification reaction, and preventing an early decline in treatment capacity.

[0142] (3) The water purification device 100 is housed in the denitrification tank 11 and has a nitrification filter medium 62 that establishes aerobic nitrifying bacteria that oxidize ammonia nitrogen in the breeding water (water to be treated).

[0143] According to the above-described configuration, denitrification treatment and nitrification treatment can be carried out simultaneously in one denitrification tank 11.

[0144] (4) As shown in Figure 3, the denitrification filter medium 61 is formed in a porous shape with a plurality of communication paths 611, and is fixed above the position where the bubbles 7 are generated. With the above configuration, the bubbles 7 are generated and pass through the communication paths 611 of the denitrification filter medium 61 as they rise in the rearing water. The bubbles 7 flow along the communication paths 611 and take on the average diameter of the communication paths 611. As a result, the denitrification reaction is carried out by the bubbles 7 whose average diameter in a floating state is the same as the average diameter of the communication paths 611, thereby accelerating the denitrification reaction.

[0145] (5) As shown in Figures 1 and 2, the water purification device 100 includes a nitrification tank 21 to which rearing water is supplied, a nitrification filter medium 62 housed in the nitrification tank 21 and adapted to settle aerobic nitrifying bacteria that oxidize the ammonia nitrogen in the rearing water, and a nitrification air supply mechanism 24 disposed at the bottom of the nitrification tank 21. The nitrification air supply mechanism 24 continuously supplies air to the rearing water stored in the nitrification tank 21 at a volumetric rate of 50% to 5000% per minute of the total volume of the rearing water, thereby exposing the nitrification filter medium 62 to air and promoting the nitrification reaction by the nitrifying bacteria under aerobic conditions.

[0146] With the above configuration, air is supplied at a volumetric rate of 50% to 5000% per minute of the storage volume of the breeding water, exposing the nitrifying filter media 62 to air to continuously perform the oxygen intake operation, thereby promoting the nitrification reaction. This makes it possible to efficiently perform nitrification treatment of the breeding water for aquatic organisms under aerobic conditions, in addition to denitrification treatment.

[0147] (6) As shown in Figure 4, the nitrification filter medium 62 is porous and has a plurality of communication channels 621, and is fixed above the position where the bubbles 7 are generated. With the above configuration, the bubbles 7 pass through the communication channels 621 of the nitrification filter medium 62 as they rise in the rearing water. The bubbles 7 flow along the communication channels 621 and take on the average diameter of the communication channels 621. As a result, the nitrification reaction is carried out by the bubbles 7, whose average diameter in the floating state is the same as the average diameter of the communication channels 621, thereby promoting the nitrification reaction.

[0148] In the water purification apparatus 100 configured as described above, it is preferable that the denitrification filter medium 61 and / or the nitrification filter medium 62 are made to be less likely to move even when affected by the air bubbles 7. For example, if the denitrification filter medium 61 is made less likely to move and the air bubbles 7 are used to perform the denitrification reaction, the fixed denitrification filter medium 61 allows the attachment of microorganisms to be maintained continuously, enabling a stable denitrification reaction over a long period of time. Microorganisms are more likely to settle on the surface of the denitrification filter medium 61, which promotes the formation of a biofilm and creates an environment conducive to the habitation of denitrifying bacteria. Furthermore, the immobility of the denitrification filter medium 61 reduces the risk of wear and tear, thereby extending the life of the denitrification filter medium 61. The same applies to the nitrification filter medium 62.

[0149] Specific methods for preventing flow include, for example, using a mesh or net-like container or fixing structure to house the denitrification filter material 61 (nitrification filter material 62) and ensuring appropriate openings or gaps to control the buoyancy caused by the bubbles 7. Alternatively, a method of resisting buoyancy by adjusting the specific gravity of the denitrification filter material 61 (nitrification filter material 62) itself can be employed. Furthermore, a structure can be adopted in which a partition or divider is installed to prevent the bubbles 7 from directly hitting the denitrification filter material 61 (nitrification filter material 62) and causing turbulence, while promoting the denitrification reaction (nitrification reaction) through a gentle water flow. By combining these methods, sufficient contact with the bubbles 7 can be achieved even when the denitrification filter material 61 (nitrification filter material 62) is difficult to flow, thereby enabling efficient and stable denitrification treatment (nitrification treatment).

[0150] <<Test Example 2>> Next, an example using the water purification device 100 will be described.

[0151] (Test Method) A pipette washer (manufactured by Ikeda Rika Co., Ltd., volume 10 liters) was used as the denitrification tank 11. In addition, porous cellulose particles (manufactured by Rengo Co., Ltd., Viscopal A (registered trademark), diameter 3 mm) were used as the denitrification filter material 61 and were filled into the denitrification tank 11.

[0152] The volume of the breeding tank 8 used was 15 liters. This breeding tank 8 was filled with 10 liters of artificial seawater (manufactured by Aquarium Systems). Furthermore, the breeding water was sufficiently aerated throughout the experiment. As a result, the breeding water in the breeding tank 8, nitrification tank 21, and denitrification tank 11 was maintained at a water temperature of 25±1°C, a salinity of 3.0-3.2%, a pH of 8.0-8.4, and a DO (dissolved oxygen) of 6-8 ppm. Since carbon was supplied by the decomposition of the cellulose used in the denitrification filter medium 61, no carbon source such as methanol was added as needed for the denitrification reaction.

[0153] Nitrification and denitrification were carried out by blowing air from the bottom of the denitrification tank 11. The amount of air supplied was measured during the nitrification and denitrification processes. The amount of air supplied was measured by installing a flow meter in the air supply line and accurately measuring the air flow.

[0154] The rearing water was periodically sampled and the nitrate nitrogen concentration in the rearing water was measured. That is, the rearing water was subjected to denitrification treatment, and the change in nitrate nitrogen concentration was measured after a predetermined time had passed from the start of the test. Here, the concentration was measured using a portable water quality measurement spectrophotometer DR900 (manufactured by HACH).

[0155] (Examples 1 to 8) Next, in the above test method, the filling rate of the denitrification filter medium 61 was set to 100%, and only the amount of air supplied was changed, and the rearing water was subjected to nitrification treatment. The change in the nitrate nitrogen concentration was measured after a predetermined time (24 hours) had elapsed since the start of the test. The measurement results are shown in Table 2.

[0156]

[0157] From the above measurement results, it was found that the nitriding treatment was performed well when the air supply rate per minute was 1 L / min to 9 L / min, and even better when it was 2 L / min to 5 L / min, and especially even better when it was 5 L / min to 9 L / min. As with the nitriding treatment, it is estimated that the nitriding treatment was also performed well when the air supply rate per minute was 1 L / min to 9 L / min, and even better when it was 2 L / min to 5 L / min, and especially even better when it was 5 L / min to 9 L / min.

[0158] This revealed that denitrification treatment was performed well when air was supplied at a volume rate of 50% to 5000% per minute of the storage volume of the water to be denitrified, thereby continuously exposing the denitrification filter material 61 to air.

[0159] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the above-described embodiments. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described.

[0160] (Aquatic Organism Distribution Management System 200) Next, an aquatic organism distribution management system 200 using the above-described water purification device 100 will be described, as shown in Fig. 8. Note that the aquatic organism distribution management system 200 may use a water purification device other than the above-described water purification device 100.

[0161] The aquatic organism distribution management system 200 enables nitrification and denitrification in a single reaction tank by fixing denitrifying microorganisms and nitrifying microorganisms to the same fixed filter material, and continuously reduces the nitrate that accumulates in fish and shellfish breeding water to nitrogen without accumulating hydrogen sulfide, thereby maintaining the water quality in the tank.This makes it possible to store aquatic organisms in a fresh state at the fishing site or local market, but since transportation to the central market and from the central market to the consumer often takes a long time, the aquatic organisms become hungry, their flavor decreases, and they are prone to producing odors.Therefore, the system is configured to allow the aquatic organisms to be delivered to consumers while maintaining sufficient flavor and preventing the generation of odors.

[0162] (Aquatic Organism Distribution Management System 200: Overview) The aquatic organism distribution management system 200 is configured to install distribution stations 204 within the distribution area to store aquatic organisms raised in treated water in a fresh state, manage them using a distribution management server 202, and enable information to be sent and received between various terminal devices including consumer terminals 5.

[0163] Specifically, the aquatic organism distribution management system 200 is installed within a distribution area where aquatic organism consumers 51 are present, and includes a distribution station 204 that breeds aquatic organisms in the treated water from the breeding tank 8 while denitrifying the treated water using the water purification device 100, a distribution management server 202 that stores installation location information indicating the installation location of the distribution station 204 and aquatic organism information including the type, size, and number of aquatic organisms being raised in the treated water from the distribution station 204, and a communication device 201 that can send and receive distribution management information including the installation location information and aquatic organism information between the distribution management server 202 and the consumer terminal 5 of the consumer 51.

[0164] Here, "aquatic organisms" refers to organisms that live in water or near water. Aquatic organisms handled at the distribution station 204 include species that are used as food or for decorative purposes. Examples of edible organisms include invertebrates, including fish and crustaceans. Examples of fish include tiger pufferfish, flounder, striped jack, grouper, and sea bream. Examples of invertebrates, including crustaceans, include abalone, sea urchin, turban shell, spiny lobster, tiger prawn, lobster, hairy crab, and red king crab. Edible fish and invertebrates are bred and kept in a natural-like breeding environment by the water purification device 100 at the distribution station 204 and then provided to consumers 51. Examples of ornamental organisms include koi carp and tropical fish.

[0165] The "consumer 51" is an individual or business operator who wishes to purchase aquatic organisms. For example, this includes an ordinary household user who wants to enjoy cooking fresh seafood at home, or a restaurant owner who runs a restaurant or izakaya and wants to quickly secure high-quality ingredients. The consumer 51 can use his or her consumer terminal 5 to access the distribution management server 202 of the distribution stations 204 installed within the distribution area and check the type, size, and inventory status of the aquatic organisms for sale. The consumer 51 can also select the optimal distribution station 204 based on his or her current location and the conditions of the aquatic organism he or she desires, and reserve or purchase the aquatic organisms. For example, if the consumer 51 desires fresh tiger pufferfish, he or she can efficiently obtain them by identifying the distribution stations 204 that have tiger pufferfish in stock through the consumer terminal 5 and selecting the nearest distribution station 204. Furthermore, the consumer 51 can smoothly receive the aquatic organisms based on the specified pickup time and location after completing the purchase procedure. This allows the consumer 51 to obtain the desired aquatic organisms in the best condition without having to go to a fishing port or wholesale market in person.

[0166] A "distribution area" refers to a geographical area established for efficient trading of aquatic organisms. Within the distribution area, multiple distribution stations 204 are located so that consumers 51 can quickly obtain aquatic organisms. The distribution area may be established based on the accessibility and demand of consumers 51. Specifically, the distribution area may be centered around urban areas or suburbs. Urban distribution areas may be areas with a high concentration of restaurants and high demand for fresh ingredients. In large cities such as Tokyo and Osaka, distribution stations 204 may be installed near train stations or downtown areas, providing a system that allows consumers 51 to easily purchase or receive aquatic organisms. In regional cities, distribution stations 204 may be installed near major transportation hubs or markets to store and sell fresh aquatic organisms caught by local fisheries.

[0167] The "water to be treated" refers to water in a breeding tank 8 used to breed aquatic organisms. Examples of the water to be treated include sewage, livestock wastewater, agricultural wastewater, industrial wastewater, seawater, and breeding water. When the water to be treated is contaminated by the metabolic products of aquatic organisms or leftover food, harmful substances such as ammonia and nitrate nitrogen accumulate, which may adversely affect the health and growth of the aquatic organisms. For example, in a breeding tank 8 for breeding fish, ammonia is generated by the decomposition of fish excrement and leftover food. If this ammonia concentrates, the living environment for the fish deteriorates. Therefore, the water to be treated is subjected to denitrification treatment by the water purification device 100, which converts the ammonia into harmless nitrogen gas, thereby maintaining an optimal environment for the aquatic organisms in the breeding tank 8.

[0168] "Denitrification" is a treatment method for converting nitrogen compounds contained in water, particularly nitrate nitrogen and nitrite nitrogen, into harmless nitrogen gas and removing them from the aquatic environment. For example, when aquatic organisms are raised in a breeding tank 8, ammonia is produced in the treated water as the aquatic organisms' metabolites and remaining food decompose. This ammonia is converted into nitrate nitrogen by the action of nitrifying bacteria, but if the nitrate nitrogen concentration becomes high, it will deteriorate the breeding environment and have a negative impact on the health of the organisms. Therefore, denitrification reduces nitrate nitrogen to harmless nitrogen gas, improving the water quality.

[0169] The "installation location information" is information indicating where the distribution station 204 is physically installed, and is information that allows the consumer 51 to quickly and accurately obtain the aquatic organisms they desire. For example, the installation location information includes a specific address or place name, such as "Tsukiji 1-chome, Chuo-ku, Tokyo" or "Umeda 2-chome, Kita-ku, Osaka," which can identify the area where the distribution station 204 is installed. The installation location information also includes coordinate information consisting of latitude and longitude so that the location of the distribution station 204 can be accurately determined by linking it with a map app or GPS function. Furthermore, the installation location information also includes additional information that makes it easy for the consumer 51 to access the location. For example, the additional information includes access condition information that includes at least one of "a five-minute walk from the nearest station," "parking available," and "along a major road."

[0170] The "aquatic organism information" is detailed information about the aquatic organisms being raised and stored at the distribution station 204. It includes the type, size, and number of the aquatic organisms, as well as additional elements such as freshness and arrival date. For example, the type of aquatic organism includes specific name information such as "tiger pufferfish," "flounder," "king crab," and "prawn." The aquatic organism information also includes specific numerical size information, such as "tiger pufferfish with a body length of 30 cm" and "king crab with a shell width of 15 cm." Furthermore, the aquatic organism information also includes inventory numbers, indicating the current storage status, such as "10 tiger pufferfish" and "50 prawns." This allows consumers 51 to check in advance whether the desired quantity is available, making it easier to plan their purchases. Furthermore, if information about freshness and arrival date is included, consumers 51 can understand the condition of the aquatic organisms and make optimal selections. For example, if a distribution station 204 is offering tiger pufferfish with the description "Arrival date: November 25, 2024" and "Freshness rank: High," consumers 51 will know that the aquatic creature has only recently arrived and can feel reassured that they can purchase it in a fresh state.

[0171] The "distribution management information" is a comprehensive data set related to the distribution station 204, and is provided to the consumer 51 to efficiently find the aquatic organisms they wish to purchase and to smoothly proceed through the purchase process. This distribution management information includes installation location information and aquatic organism information, providing the consumer 51 with information to help them select an aquatic organism. For example, the distribution management information includes the address and GPS coordinates of the distribution station 204 as installation location information, and details of the aquatic organisms stored at the distribution station 204 as aquatic organism information. In addition to the specific location, the distribution management information also includes access information including at least one of the nearest train station and the presence or absence of parking, allowing the consumer 51 to easily find the distribution station 204 closest to their current location.

[0172] The distribution management information also includes auxiliary information that makes it easier for the consumer 51 to plan their purchase. For example, by providing auxiliary information such as "distance from current location: 2.5 km" and "estimated waiting time: 15 minutes," the consumer 51 can select the optimal distribution station 204 taking into consideration travel time and the time required for pickup.

[0173] In addition to the installation location information and aquatic life information, the distribution management information preferably includes additional information that allows consumers 51 to purchase aquatic life more conveniently and effectively. An example of such additional information is service information provided by the distribution station 204. By including service types including at least one of "immediate purchase available," "reservation only," and "home delivery available" as service information, consumers 51 can select an appropriate distribution station 204 according to their purchasing purpose and time constraints. Furthermore, if business hours and pickup times are included as service information, consumers 51 can more accurately plan their visits and transactions. For example, if service information such as "business hours: 9:00-18:00" and "pickup times: 10:00-16:00" is included, convenience for consumers 51 can be significantly improved.

[0174] The distribution management information may also include handling information regarding the handling of aquatic organisms. For example, if handling information for a specific aquatic organism includes "the time of day when the organism is freshest," "characteristics of the storage environment," and "recommended cooking methods," consumers 51 can more easily visualize how to use the organism after purchase. Specific examples of handling information include "Today's recommendation: Tiger pufferfish (40 cm in length) delivered this morning" and "Cooking example: Ideal for grilling or as sashimi." Furthermore, it is preferable that the distribution management information also include personalized recommendation information based on the purchase history and preferences of consumers 51. For example, if a consumer 51 previously purchased kuruma shrimp, the distribution management information may include recommendation information that suggests related aquatic organisms, such as "recommended aquatic organism: fresh king crab caught in the same place," thereby encouraging additional purchases.

[0175] According to the above configuration, by performing denitrification treatment on the treated water, a distribution station 204 is installed within the distribution area, where aquatic organisms reared in the treated water can be kept fresh. This allows consumers 51 in the distribution area to obtain the aquatic organisms in a shorter time than if they were purchased from conventional distribution channels such as fishing ports or central wholesale markets. This allows consumers 51 to obtain the aquatic organisms in a fresh state. Furthermore, the denitrification treatment by the water purification device 100 maintains the water quality in the breeding tanks 8 at an optimal condition for breeding, thereby maintaining the freshness of the aquatic organisms at the distribution station 204 for a long period of time. Furthermore, when aquatic organisms are reared and stocked at the distribution station 204, they do not emit an unpleasant odor like geosmin, so the odor is not transferred to seafood. Furthermore, while conventional live fish tanks require a sufficiently low water temperature to suppress metabolism and keep the aquatic organisms without feeding, which prevents them from fattening, by rearing the aquatic organisms at an appropriate temperature in the distribution station 204, they can feed and fatten while being stocked. Furthermore, when aquatic organisms, including invertebrates such as oysters, are raised in a low-salinity environment, the umami components of the aquatic organisms can be increased. By installing a distribution station 204 in the distribution area that raises and stores aquatic organisms in this manner in a comfortable environment, consumers 51 in the distribution area can obtain the aquatic organisms in a shorter time than if they were to obtain them from a fishing port or central wholesale market, and aquatic organisms that have sufficient umami and are prevented from generating odors can be delivered to consumers 51.

[0176] The aquatic organism distribution management system 200 can also be applied to marine business. Here, "marine business" refers to all businesses that utilize and build upon the value and appeal of marine resources in marine base regions, including the sea and fishing villages. A "marine base region" refers to a geographical area centered on the sea, fishing villages, and coastal areas that form the foundation of the marine industry, and refers to a region where natural resources, cultural resources, and economic activities come together to form regional value. Thus, while distribution regions are places where value is consumed by consumers 51, marine base regions are supply centers that create value. "Marine base resources" is a collective term for the diverse resources with natural, cultural, and economic value that exist in marine base regions centered on the sea and fishing villages. The scope of marine base resources extends beyond traditional fishing and aquaculture to include tourism, education, environmental conservation, the creation of regional brands, and even complex business forms that integrate these.

[0177] By establishing distribution stations 204 within distribution areas, the aquatic organism distribution management system 200 enables new business development by expanding marine industry operations from marine industry base regions to distribution areas. Specifically, the distribution stations 204 serve as bases for efficiently delivering marine resources from marine industry base regions to urban areas and local communities, allowing consumers 51 to experience the value and appeal of marine industry without having to directly visit the sea or fishing villages of the marine industry base regions. For example, in the tourism industry, experiential tourism can be conducted using the distribution stations 204, making it easy to provide urban consumers 51 with the local specialties and culture of the marine industry base regions. In addition, in the education industry, by developing programs to learn about the marine environment and the ecology of aquatic organisms at the distribution stations 204, it is possible to provide the same level of education to urban consumers 51 far from the marine industry base regions. Furthermore, the distribution stations 204 utilize the unique technologies and know-how of marine industry base regions in breeding and water quality management, contributing to environmental conservation projects and the creation of regional brands. For example, by adopting a sustainable breeding system that utilizes water purification technology and a system that maintains the freshness of local specialties, it is possible to provide high-quality products to urban consumers 51 who are far from the maritime base region, thereby improving the brand power of the maritime base region.

[0178] Furthermore, by storing information about the locations of distribution stations 204 and aquatic organism information including the type, size, and number of aquatic organisms in distribution management server 202, distribution management server 202 can provide the location information and aquatic organism information in real time in response to a request from consumer terminal 5. This allows consumer 51 to select the optimal distribution station 204 based on their current location and the conditions of the aquatic organisms they desire, as shown in Figures 9 to 11, for example. Specifically, by checking information about the location and distance of distribution station 204 via consumer terminal 5 and comparing information about the inventory status and freshness of the aquatic organisms, it becomes possible to select the distribution station 204 from which aquatic organisms can be obtained most efficiently.

[0179] Furthermore, the provision of information via the distribution management server 202 makes it easier for consumers 51 to plan their purchases in advance. For example, by utilizing auxiliary information including at least one of "distance from current location" and "estimated waiting time" contained in the distribution management information, it becomes possible to adjust schedules to minimize travel time and collection time. Furthermore, because the distribution management information includes information on the handling of aquatic organisms and service information, consumers 51 can select the purchasing method that best suits their lifestyle and situation, such as immediate purchase, reservation, or home delivery.

[0180] Furthermore, because the management status of aquatic organisms at distribution station 204 can be grasped in real time, consumers 51 can purchase the most valuable aquatic organisms at the appropriate time by referring to information such as "Today's Recommendations" and "Freshness Rank." As a result, the above configuration realizes an environment in which consumers 51 can efficiently obtain the aquatic organisms they desire under optimal conditions.

[0181] (Aquatic Organism Distribution Management System 200: Distribution Station 204) The distribution station 204 is installed in a distribution area where aquatic organism consumers 51 are present and is configured to raise aquatic organisms while subjecting treated water to denitrification treatment using the water purification device 100. Specifically, the distribution station 204 is installed at one or more locations within the distribution area where consumers 51 are present in order to increase the distribution efficiency of aquatic organisms, and is equipped with facilities and functions for raising and storing aquatic organisms using treated water. The distribution station 204 enables aquatic organisms to be delivered to consumers 51 quickly and appropriately while maintaining the aquatic organisms in a fresh state. Specifically, the distribution station 204 is equipped with a breeding tank 8 that stores treated water for raising aquatic organisms. The treated water in the breeding tank 8 is subjected to denitrification treatment using the water purification device 100. As a result, harmful substances, including ammonia and nitrate nitrogen, are neutralized in the breeding tank 8, thereby maintaining an optimal environment for raising aquatic organisms. As a result, distribution station 204 is able to provide consumers 51 with high-quality aquatic creatures.

[0182] The distribution station 204 also includes a breeding control device 3 that controls the operation of the water purification device 100. The breeding control device 3 monitors water quality and automatically adjusts treatment operations, thereby realizing a stable breeding environment. The distribution station 204 also includes a breeding management device 2041 that manages aquatic organism information, including the type, size, and number of aquatic organisms, and transmits this information together with installation location information to the distribution management server 202. The breeding management device 2041 transmits the aquatic organism information and installation location information to the distribution management server 202, allowing the distribution management server 202, which receives information from each distribution station 204, to allow the consumer 51 to check the inventory status and detailed information about the nearest distribution station 204 in real time.

[0183] In this way, the distribution station 204 has a breeding tank 8 in which treated water used for breeding aquatic organisms is stored, a water purification device 100 that denitrifies the treated water in the breeding tank 8, a breeding control device 3 that controls the processing operation of the water purification device 100, and a breeding management device 2041 that manages installation location information indicating the installation location of the distribution station 204 and aquatic organism information including the type, size, and number of aquatic organisms, and is capable of data communication with the distribution management server 202.

[0184] As a result, by installing distribution stations 204 within the distribution area, consumers 51 do not need to travel to remote locations such as fishing ports or central wholesale markets, and can obtain fresh aquatic organisms in a shorter time. Furthermore, if multiple distribution stations 204 are installed dispersedly within the area, accessibility for consumers 51 is improved, making it easier for consumers 51 to plan their purchases. For example, location information and inventory status of the nearest distribution station 204 are provided via the distribution management server 202, so consumers 51 can select the station closest to their current location and efficiently purchase and receive aquatic organisms.

[0185] (Aquatic Organism Distribution Management System 200: Distribution Station 204: Breeding Tank 8) The breeding tank 8 is a dedicated tank for breeding and storing aquatic organisms. The breeding tank 8 is configured to provide an environment suitable for the habitation of aquatic organisms, and the size and structure of the breeding tank 8 are designed according to the type and quantity of aquatic organisms to be raised. It is preferable that the size and structure of the breeding tank 8 be changeable so that an optimal environment can be continuously maintained for a variety of aquatic organisms, including not only large fish and invertebrates but also small ornamental fish such as tropical fish. Furthermore, it is preferable that the breeding tank 8 has a function to automatically adjust environmental factors such as the water temperature, dissolved oxygen, and pH value of the treated water according to the type of aquatic organism, etc., by linking with the breeding control device 3.

[0186] (Aquatic Organism Distribution Management System 200: Distribution Station 204: Water Purification Device 100) The water purification device 100 has the function of properly purifying the water to be treated used in the breeding tanks 8 in the distribution station 204, removing harmful substances that accumulate in the breeding tanks 8, and maintaining optimal water quality in order to maintain an environment in which aquatic organisms can grow healthily. Specifically, the water purification device 100 has the function of performing a denitrification treatment on the water to be treated. Harmful nitrogen compounds such as ammonia and nitrate nitrogen contained in the water to be treated are converted into harmless nitrogen gas by the action of denitrifying bacteria, improving the water quality in the breeding tanks 8. This denitrification treatment removes substances that adversely affect the growth environment of aquatic organisms, enabling healthy breeding. Note that either aerobic denitrifying bacteria or anaerobic denitrifying bacteria may be used for the denitrification treatment.

[0187] The water purification device 100 also has the function of maintaining water quality elements, including at least one of the water temperature, dissolved oxygen, and pH value, in the breeding aquarium 8 within a certain range. Furthermore, the water purification device 100 is configured to operate in cooperation with the breeding control device 3. The breeding control device 3 monitors water quality data in the breeding aquarium 8 in real time via sensors and sends instructions to the water purification device 100, thereby automatically carrying out the purification process. A specific configuration example of the water purification device 100 will be described later.

[0188] (Aquatic Organism Distribution Management System 200: Distribution Station 204: Rearing Control Device 3) The rearing control device 3 has a function of optimizing the rearing environment in cooperation with the water purification device 100 and other related equipment to maintain the health and freshness of the aquatic organisms reared in the rearing tanks 8 of the distribution station 204. Specifically, the rearing control device 3 has a sensor system for monitoring water quality elements such as water temperature, dissolved oxygen, pH, and turbidity in real time within the rearing tanks 8. The water quality element data obtained by the sensor system is sent to the control unit of the rearing control device 3 and compared with certain reference values. If any of the water quality elements deviates from the reference values, the rearing control device 3 automatically issues instructions to the water purification device 100, temperature control equipment, etc., and executes processing to quickly correct the environment. This enables the rearing control device 3 to constantly maintain the environment within the rearing tanks 8 in an optimal state for the aquatic organisms.

[0189] The rearing control device 3 also has the function of managing the environment according to the type and characteristics of the aquatic organisms reared in the distribution station 204. For example, to create an appropriate rearing environment for aquatic organisms such as fish, invertebrates, and ornamental fish, which have different optimum ranges for temperature and oxygen concentration, individual management profiles can be set based on the characteristics of each organism. It is preferable that the management profiles be changeable in cooperation with the distribution management server 202. It is also preferable that the rearing control device 3 has the function of recording and analyzing water quality factors. In this case, storing the history of the rearing environment makes it possible to track trends in environmental changes and the causes of problems. Information on water quality factors is transmitted to the distribution management server 202 and used to ensure the quality of the aquatic organisms provided to consumers 51 and to improve the overall distribution system. A specific configuration example of the rearing control device 3 will be described later.

[0190] (Aquatic Organism Distribution Management System 200: Distribution Station 204: Rearing Management Device 2041) The rearing management device 2041 manages information about the aquatic organisms being reared in the distribution station 204 and has the function of communicating data with the distribution management server 202, making it possible to record and manage the rearing status of the aquatic organisms. Specifically, the rearing management device 2041 has the function of collecting and recording detailed information such as the type, size, number, freshness, and arrival date of the aquatic organisms being reared in the rearing tanks 8. This detailed information is updated in real time and transmitted to the distribution management server 202. This allows consumers 51 and sellers to obtain accurate information about the inventory status and rearing environment of the aquatic organisms by accessing the distribution management server 202 via the consumer terminal 5 or seller terminal 205.

[0191] The rearing management device 2041 also has a function of assisting in monitoring and controlling the rearing environment in cooperation with the rearing control device 3 and the water purification device 100. For example, it acquires water quality elements including water temperature, dissolved oxygen, and pH value to check whether a rearing environment suitable for aquatic organisms is being maintained. These water quality elements are recorded and accumulated in the distribution management server 202 via the rearing management device 2041, and are useful for quality control of the aquatic organisms.

[0192] (Aquatic Organism Distribution Management System 200: Communication Device 201) In the aquatic organism distribution management system 200, the communication device 201 has the function of transmitting and receiving information between each component of the entire system, such as the distribution management server 202, the breeding management device 2041, the consumer terminal 5, the seller terminal 205, and the monitoring device 5 for remote monitoring. The communication device 201 also has the function of enabling communication via the Internet 206, as well as direct data communication between each component. Specifically, the communication device 201 exchanges information in real time with the breeding management device 2041 in the distribution station 204, thereby enabling the transmission of breeding status and inventory data, such as the type, size, number, and freshness of the aquatic organisms, to the distribution management server 202. This makes it possible to provide the latest information to consumers 51 and sellers in response to requests from the consumer terminal 5 and seller terminal 205.

[0193] Furthermore, the communication device 201 has a function for performing data communication with the breeding management device 2041 via the Internet 206, making it possible to grasp the breeding status of geographically distant distribution stations 204 from remote locations. The communication device 201 also has a data encryption function as a security measure, ensuring confidentiality and safety of communication data in both direct communication and indirect communication via the Internet 206. Furthermore, the communication device 201 has a function for detecting communication errors and automatic recovery in the event of a failure, thereby enhancing the reliability of the system.

[0194] (Aquatic Organism Distribution Management System 200: Distribution Management Server 202) The distribution management server 202 has the function of integrating and managing information between each component of the entire system, such as the distribution station 204, consumer terminal 5, and seller terminal 205, to ensure smooth operation. The hardware configuration of the distribution management server 202 includes, for example, a multi-core CPU with high-speed processing capabilities, high-capacity memory (RAM), and a large-capacity, highly reliable storage system (SSD or RAID-configured HDD). It also has a high-speed network interface to ensure stable data communication with the communication device 201 and the management database server 203. Furthermore, the distribution management server 202 is equipped with redundant power supplies and cooling systems, enabling continuous operation.

[0195] Based on the above hardware configuration, the distribution management server 202 has realized the following various functions. Specifically, the distribution management server 202 has a function for managing installation location information and aquatic life information included in the distribution management information. This information is recorded in the management database server 203 and provided to the consumer terminal 5 and the seller terminal 205 via the distribution management server 202. For example, in response to a request from the consumer terminal 5, information including the installation location of the distribution station 204 and the type, size, and number (inventory) of the aquatic life is transmitted in real time. This function allows the consumer 51 to quickly and accurately find the aquatic life they need and make a purchase plan.

[0196] The distribution management server 202 also integrates data collected from the rearing management device 2041 and the water purification device 100 in the distribution station 204 via the communication device 201, and generates information on the inventory status and rearing environment based on the integrated data. The distribution management server 202 can also communicate with the consumer terminal 5 and the seller terminal 205 via the Internet 206, making it possible to provide information in real time to geographically distant consumers 51, etc. Furthermore, the distribution management server 202 has a function of protecting data during communication by encrypting the data and preventing unauthorized access and information leaks. The distribution management server 202 also has a function of user authentication and access control.

[0197] In addition, when the distribution management information includes location information of the consumer terminal 5, the distribution management server 202 preferably has a function of including the distance between the consumer terminal 5 and the distribution station 204 in the distribution management information based on the location information and installation location information of the distribution station 204. According to this function, when multiple distribution stations 204 are installed, as shown in FIG. 9 , the distribution management server 202 acquires the location information of the consumer terminal 5, calculates the distance between the consumer terminal 5 and the distribution station 204 based on the location information and the installation location information of the multiple distribution stations 204, and transmits the distance information to the consumer terminal 5 as distribution management information. This allows the consumer 51 to check the location and distance of the distribution station 204 closest to their current location via their own terminal. This allows the consumer 51 to select the distribution station 204 that is the optimal purchasing location that minimizes travel time and costs for obtaining the desired aquatic organisms.

[0198] Furthermore, when the communication device 201 is capable of transmitting and receiving distribution management information between the distribution management server 202 and the seller terminal 205 of a seller who sells aquatic organisms using the distribution station 204, it is preferable that the distribution management server 202 has a function of including replenishment information in the distribution management information and transmitting it to the seller terminal 205 when the number of aquatic organisms stored at the distribution station 204 is below a predetermined number.

[0199] According to the above function, distribution management information can be transmitted and received between the seller terminal 205 of a seller who sells aquatic organisms using the distribution station 204 and the distribution management server 202. When the number of aquatic organisms stored in the distribution station 204 reaches or falls below a predetermined number, replenishment information is included in the distribution management information and transmitted to the seller terminal 205. This allows the seller to grasp the inventory status of the aquatic organisms stored in the distribution station 204 in real time through his / her own seller terminal 205. As a result, the seller can take countermeasures such as adding more aquatic organisms. For example, by taking countermeasures such as creating a replenishment plan in advance, the seller can prevent lost sales opportunities due to stockouts and realize efficient inventory management. Furthermore, the automatic transmission of replenishment information reduces the work required for the seller to check inventory, which was previously required.

[0200] (Aquatic Organism Distribution Management System 200: Management Database Server 203) The management database server 203 has the function of recording, organizing, and managing information for the entire system of the aquatic organism distribution management system 200. The management database server 203 operates in conjunction with the distribution management server 202 and the communication device 201, and is capable of providing accurate information in real time to each component in the system, such as the consumer terminal 5 and the seller terminal 205.

[0201] The management database server 203 is equipped with a high-performance storage system and data processing capabilities, and is capable of efficiently storing and managing large amounts of data. The management database server 203 uses multiple data tables to logically classify and organize the information required within the system. Specifically, the management database server 203 has an aquatic organism table, a distribution station information table, a transaction history table, and a consumer information table. Note that, if the aquatic organism distribution management system 200 becomes large-scale, it is preferable that each table be managed by its own server. In other words, the management database server 203 may be composed of a group of multiple servers.

[0202] The aquatic organism table is a data table for recording detailed information about aquatic organisms bred and stored at the distribution station 204. Each aquatic organism is assigned a unique identification number, an "aquatic organism ID," so that each piece of data can be uniquely managed. In addition to the "aquatic organism ID," the aquatic organism table also includes the following fields: "type," "size," "inventory," "arrival date," and "freshness rank." The "type" field records the specific name of the aquatic organism being bred, such as a tiger pufferfish, king crab, or shrimp. The "size" field records numerical information, such as "body length 30 cm" for a tiger pufferfish and "shell width 15 cm" for a king crab. This information is intended to help consumers 51 understand the specific size of the aquatic organisms.

[0203] The "inventory quantity" stores specific inventory information, such as the number of tiger pufferfish currently being raised at the distribution station 204 (10 fish) and the number of kuruma shrimp (50 fish). The "arrival date" records the date on which the aquatic organisms arrived at the distribution station 204 and is used to track their freshness and distribution status. The "freshness rank" records ranking information such as "high," "medium," or "low," allowing the quality status of the aquatic organisms to be seen at a glance. In this way, the aquatic organism table functions as a database that improves the efficiency of the management of aquatic organisms at the distribution station 204 and enables accurate information to be provided to consumers 51.

[0204] The distribution station information table is a data table for recording information about the location and facilities of the distribution station 204. In this distribution station information table, a unique identification number called a "station ID" is assigned to each distribution station 204, allowing each distribution station 204 to be uniquely identified. In addition, the "installation location" records the specific address and GPS coordinates of the distribution station 204, and includes information that can accurately identify the installation location, for example, in the form of "Tsukiji 1-chome, Chuo-ku, Tokyo."

[0205] The distribution station information table also has the following fields: "Installation location," "Breeding capacity," "Equipment status," and "Nearest transportation." "Breeding capacity" records the maximum number of aquatic organisms that the breeding tank 8 can accommodate, indicating the breeding capacity of the distribution station 204. The breeding capacity information is used to understand the capacity of each distribution station 204 and operate it efficiently. "Equipment status" records the operating status of each piece of equipment, including the breeding control device 3 and the water purification device 100, and is used to maintain and manage the equipment and optimize its operating rate. "Nearest transportation" describes information to make it easier for consumers 51 to access the distribution station 204, and includes specific access information, such as "a five-minute walk from the nearest station."

[0206] The transaction history table is a data table for recording transaction information between consumers 51 and sellers and managing the history of those transactions. In this transaction history table, a unique identification number called a "transaction ID" is assigned to each transaction, allowing transaction data to be managed uniquely. The "consumer ID" records the identification number of the consumer 51 who conducted the transaction, and the "seller ID" records the identification number of the seller corresponding to the transaction, allowing the parties involved in the transaction to be identified.

[0207] The transaction history table also has the following fields: "Purchased Item," "Purchased Quantity," "Transaction Amount," and "Transaction Date and Time." "Purchased Item" records the specific species of aquatic life purchased in the transaction, such as tiger pufferfish or king crab. "Purchased Quantity" records the number of each item purchased, and indicates the details of the purchase, for example, "two tiger pufferfish." "Transaction Amount" records the total amount paid, and financial data related to the transaction, such as "5,000 yen." "Transaction Date and Time" records the specific date and time the transaction was completed, making it possible to accurately determine when each transaction took place.

[0208] The consumer information table is a data table for managing the profile information and purchase history of consumers 51 who use the aquatic organism distribution management system 200. In this consumer information table, each consumer 51 is assigned a unique identification number called a "consumer ID," allowing each consumer's information to be managed uniquely. The consumer information table also has the following fields: "Name," "Address," "Purchase History," and "Favorites."

[0209] The "Name" field records the name of the consumer 51 and is used to identify the individual consumer 51 during transactions, inquiries, etc. The "Address" field records the delivery destination and registered address and is used as necessary information when the purchased aquatic organisms are delivered. The "Purchase History" field records the aquatic organisms that the consumer 51 has purchased in the past and their details. For example, it includes information such as specific purchase details, such as "two tiger pufferfish" and "one king crab," as well as the transaction date and time and transaction amount. Furthermore, the "Favorites" field lists aquatic organisms that the consumer 51 frequently purchases or is interested in. For example, if "prawns" and "flounder" are registered, the consumer 51 can easily select the aquatic organisms the next time they make a purchase.

[0210] (Aquatic Organism Distribution Management System 200: Distribution Management Program) As shown in Figure 12, the distribution management server 202 executes a distribution management program on a computer that serves as the processing unit, thereby realizing distribution management processing that enables consumers 51 to efficiently search for, select, purchase, and smoothly receive aquatic organisms through data communication with each component of the aquatic organism distribution management system 200, such as the consumer terminal 5, seller terminal 205, and distribution station 204. In other words, the distribution management program is made up of multiple processing steps (S1) to (S9), and each of the processing steps (S1) to (S9) is executed by a computer, thereby giving the distribution management server 202 multiple functions.

[0211] Specifically, the distribution management program executes a process of accepting inquiry information from the consumer 51, acquiring information on the installation locations of the distribution stations 204 and information on aquatic organisms, and combining this with the location information of the consumer 51 to present optimal options. The program then executes a process of managing a series of processes from when the consumer 51 selects the aquatic organism they want to reserve and purchase. After the purchase is complete, the program also executes a series of processes, including providing instructions on how to hand over the aquatic organisms and smoothly progressing the process until the consumer finally receives the aquatic organisms.

[0212] The distribution management program can be installed simply on an information processing device such as a personal computer or tablet terminal to cause the information processing device to function as distribution management server 202. The program may be distributed in a state recorded on a computer-readable recording medium such as a CD-ROM or USB memory, or may be distributed via a two-way communication network or communication line such as the Internet or a one-way communication network such as television broadcasting.

[0213] (Inquiry Information Reception Process S1) First, as the first step of the distribution management program, reception process S1 is executed to receive inquiry information sent from consumer 51 or a seller. As a result, distribution management server 202 has the function of receiving requests from consumer terminal 5 via communication device 201 and analyzing the request content. For example, if consumer 51 wishes to "purchase tiger pufferfish" and wants to check its stock and sales locations, this inquiry information will include specific request content such as "Type: tiger pufferfish" and "Stock confirmation: Yes." This information is intended to convey the conditions regarding the aquatic life and services that consumer 51 needs, and is used as basic data for accurately executing subsequent processes (such as obtaining installation location information and checking stock).

[0214] Furthermore, in the inquiry information reception process S1, the format and content of the input information are verified to ensure the consistency and accuracy of the data. For example, if the consumer 51 mistakenly inputs an invalid aquatic life species name, an error check is performed in this process, and an appropriate error message is returned so that the consumer 51 can re-input the correct information.

[0215] (Process S2 for acquiring installation location information and aquatic organism information) Next, process S2 for acquiring installation location information and aquatic organism information is executed. As a result, the distribution management server 202 has the function of acquiring necessary data from the management database server 203 based on inquiry information from the consumer 51. In other words, the distribution management server 202 acquires installation location information indicating the specific installation location of the distribution station 204 and detailed aquatic organism information regarding the aquatic organisms stored in the distribution station 204.

[0216] Specifically, the distribution management server 202 analyzes the inquiry information sent from the consumer terminal 5 and transmits an appropriate data request to the management database server 203. This data request includes, for example, conditions such as "information on distribution stations 204 that have tiger pufferfish in stock" or "detailed information on distribution stations 204 installed in a specific area." Based on this data request, the management database server 203 extracts relevant data from the aquatic organism table and distribution station information table and transmits it back to the distribution management server 202. The acquired installation location information includes the address and GPS coordinates of the distribution station 204, as well as detailed access information (e.g., whether there is a nearest train station or parking), helping the consumer 51 easily access the distribution station 204. The aquatic organism information also includes specific data such as the type, size, inventory quantity, freshness rank, and arrival date of the aquatic organisms stored at the distribution station 204, and is provided to the consumer 51 as information for making a purchase decision.

[0217] (Location information acquisition process S3 of consumer terminal 5) Next, location information acquisition process S3 is executed to acquire location information indicating the current location of the consumer 51. As a result, the distribution management server 202 has the function of communicating with the consumer terminal 5 and acquiring location information either when the consumer 51 inputs their current location or by using the GPS function of the consumer terminal 5. This location information includes an address or place name manually entered by the consumer 51, or numerical information of latitude and longitude based on GPS data. For example, location information is acquired in the format of "Chuo-ku, Tokyo" or "latitude 35.682839, longitude 139.759455."

[0218] The acquired location information is used as basic data for calculating the distance to the distribution station 204 desired by the consumer 51. The location information is then utilized in the subsequent distance information calculation process S4, and is used as a basis for the consumer 51 to select the nearest or most easily accessible distribution station 204.

[0219] Furthermore, the location information acquisition process S3 supports both cases where the consumer 51 manually inputs current location information and cases where GPS data is automatically acquired. This makes it possible to meet the diverse needs of consumers 51 regardless of the type or usage status of the consumer terminal 5. Furthermore, to protect the privacy of the consumer 51, the acquisition and transmission of location information is performed securely through encrypted communication.

[0220] (Distance information calculation process S4) Next, calculation process S4 is executed to calculate the distance between the consumer 51 and the distribution station 204 based on the location information of the consumer terminal 5 and the installation location information of the distribution station 204. As a result, the distribution management server 202 has the function of calculating the straight-line distance between two points using the location information (latitude and longitude data) of the consumer terminal 5 acquired in advance and the installation location information (latitude and longitude) of the distribution station 204 recorded in the distribution station information table.

[0221] It is preferable that distance information be provided not only as a straight-line distance but also as travel time that takes into account the means of transportation and road conditions. For example, the calculation result may be specifically displayed as "Distance: 2.5 km, approximately 30 minutes on foot." This allows the consumer 51 to select the optimal distribution station 204 while comparing travel time and convenience. It is also preferable that, if there are multiple distribution stations 204, the system also includes a process for quickly calculating the distance between each station and listing the closest or most accessible candidates.

[0222] (Transmission Process S5 of Distribution Management Information) Next, in response to a request from the consumer terminal 5, a transmission process S5 is executed to provide the consumer 51 with distribution management information regarding the distribution station 204. As a result, the distribution management server 202 has the function of accessing the management database server 203 and acquiring installation location information and aquatic organism information based on the request received by the distribution management server 202 from the consumer terminal 5. The acquired information is organized according to the distance from the current location of the consumer 51 and the access conditions, and multiple candidate distribution stations 204 are displayed on the consumer terminal 5 as distribution management information. The distribution management information is then transmitted to the consumer terminal 5. As a result, for example, as shown in FIG. 9 , the name, distance, and business hours of each distribution station 204 are displayed on the consumer terminal 5, allowing the consumer 51 to visually check the information and select the nearest or most suitable distribution station 204.

[0223] As shown in Figure 10, when a consumer 51 selects a specific distribution station 204 on the consumer terminal 5, a detail request requesting details about the selected distribution station 204 is sent to the distribution management server 202. Upon receiving this detail request, the distribution management server 202 executes a process to provide additional detailed information about the aquatic organisms stored at the selected distribution station 204. The added information includes the type, size, inventory quantity, selling price, purchase price, arrival date, and production area of ​​the aquatic organism, allowing the consumer 51 to check all the information necessary when selecting an aquatic organism. For example, if the "Higashi Ward Fisheries Center" is selected, the inventory status and prices of tiger pufferfish and king crabs stored at the center are displayed in detail.

[0224] In the transmission process S5, emphasis is placed on the accuracy and visibility of the distribution management information, and a system is set up to provide information in a format that is easily understandable to the consumer 51. For example, icons of distribution stations 204 and icons of the consumer terminal 5 are displayed on a map showing roads, railroads, landmarks, etc., with the distance between the icons corresponding to the actual distance or the actual travel time. In addition, the display content is updated in real time, allowing the consumer 51 to make decisions based on the latest information. As a result, the consumer 51 can select the optimal distribution station 204 and efficiently obtain aquatic organisms while minimizing travel time and costs.

[0225] Furthermore, when multiple distribution stations 204 are displayed on the consumer terminal 5 and the consumer 51 sends a request to check the inventory status of a specific aquatic organism, such as a tiger pufferfish, the distribution management server 202 acquires the relevant data and transmits it to the consumer terminal 5 as distribution management information. This process allows the consumer 51 to check information such as the inventory status and price of tiger pufferfish at the selected distribution station 204. Specifically, as shown in FIG. 11 , detailed information about tiger pufferfish for each distribution station 204 is displayed in list form on the consumer terminal 5. This list includes items such as the system ID, system name, installation location, distance, size, sales price, estimated waiting time, and business hours, allowing the consumer 51 to compare the inventory information of each distribution station 204. For example, detailed information about the "Higashi Ward Fisheries Center" displays that there are 15 40 cm tiger pufferfish in stock, with a selling price of 3,000 yen per fish and an estimated waiting time of 5 minutes. Furthermore, detailed information about the "Kita Ward Fish Center" displays that there are 8 fish in stock and a selling price of 2,800 yen. This allows the consumer 51 to compare detailed information of each distribution station 204 using the consumer terminal 5.

[0226] As a result, consumer terminal 5 not only displays installation location information but also displays detailed information such as stock status, price, and other conditions for each selected aquatic organism, allowing consumer 51 to easily select a distribution station 204 that suits his or her needs and budget. This not only increases convenience for consumer 51, but also makes it possible for distribution management server 202 to promote inventory distribution among distribution stations 204 and efficient distribution, and to select the optimal distribution station 204 for consumer 51, enabling him or her to quickly and accurately obtain aquatic organisms.

[0227] (Aquatic Organism Selection and Reservation Process S6) Next, the consumer 51 selects an aquatic organism offered at the distribution station 204, and a process for reserving the aquatic organism is executed. As a result, the distribution management server 202 has the function of accessing the management database server 203 and updating and managing inventory information based on the selection request received by the distribution management server 202 from the consumer terminal 5.

[0228] Specifically, the consumer 51 selects the desired type, size, and quantity based on the detailed information of the aquatic organisms presented in the distribution management information transmission process S5 via the consumer terminal 5. This selected information is transmitted as a selection request from the consumer terminal 5 to the distribution management server 202. The distribution management server 202 analyzes the received selection request and checks the stock status of the corresponding aquatic organisms by querying the management database server 203. If it is confirmed that a reservation is possible, the selected quantity is temporarily reserved and the stock data is updated.

[0229] Furthermore, when the reservation is confirmed, the distribution management server 202 generates detailed information such as a reservation number, scheduled delivery time, and delivery location, and transmits this detailed information to the consumer terminal 5. For example, when consumer 51 reserves a tiger pufferfish, the distribution management server 202 transmits information such as "reservation number: 12345," "delivery location: Higashi Ward Fisheries Center," and "delivery time: 15:00" to the consumer terminal 5. This allows consumer 51 to confirm that the reservation has been completed based on the information displayed on the consumer terminal 5.

[0230] In the reservation process S6, the distribution management server 202 can also handle requests such as canceling a reservation or changing the quantity. If the consumer 51 cancels a reservation, the distribution management server 202 updates the inventory by updating the relevant data in the management database server 203. This real-time update function ensures that the inventory information of the distribution station 204 is always kept up to date.

[0231] (Payment Process S7) Next, payment process S7 is executed to confirm the transaction between the consumer 51 and the distribution station 204. As a result, the distribution management server 202 has the function of receiving a payment request from the consumer terminal 5 and completing the payment using an appropriate settlement method.

[0232] Specifically, to confirm the reservation of the aquatic organism selected by the consumer 51, payment processing is initiated based on a payment request from the consumer terminal 5. The distribution management server 202 confirms the payment method (credit card, electronic money, bank transfer, etc.) specified by the consumer 51 and processes the transaction in cooperation with a payment gateway. For example, if the consumer 51 selects a credit card, the distribution management server 202 tokenizes the card information and sends it to the payment gateway. When the payment result is returned, the distribution management server 202 analyzes the result and proceeds to the next stage of processing.

[0233] If the payment is successful, the distribution management server 202 records the transaction information in the management database server 203 and updates the confirmation status of the transaction. It also sends a payment completion notice to the consumer terminal 5 to inform the consumer 51 that the transaction has been successfully completed. This notice includes the transaction ID, payment amount, details of the reserved aquatic life, delivery date and time, etc., allowing the consumer 51 to confirm the purchase details. On the other hand, if the payment fails, the distribution management server 202 analyzes the reason and sends an error message to the consumer terminal 5. This allows the consumer 51 to select a different payment method or try again.

[0234] (Delivery Guidance Process S8) Next, a delivery guidance process S8 is executed to provide detailed information for the consumer 51 to smoothly receive the aquatic organism that he or she has reserved and purchased. As a result, the distribution management server 202 has the function of transmitting delivery guidance to the consumer terminal 5.

[0235] Specifically, the distribution management server 202 organizes the delivery location, delivery time, details of the reserved aquatic organisms, and the like, based on the transaction information recorded in the management database server 203. The organized transaction information is sent to the consumer terminal 5 and provided to the consumer 51 so that the consumer 51 can smoothly proceed with the pickup procedure. For example, if the consumer 51 picks up two reserved tiger pufferfish at the Higashi-ku Fisheries Center, the distribution management server 202 generates specific delivery instructions such as "Delivery location: Higashi-ku Fisheries Center," "Delivery time: 15:00-16:00," and "Type: tiger pufferfish (size 40 cm) x 2," and sends this to the consumer terminal 5. The delivery instructions also include access information to the distribution station 204, and the distribution management server 202 provides information on the nearest train station, the location of a parking lot, and the location of a pickup window on-site, based on the installation location information.

[0236] The delivery guidance process S8 also implements a real-time update function to further enhance convenience for the consumer 51. For example, if there is a change in the congestion situation at the distribution station 204 or the available delivery time, the distribution management server 202 immediately updates the information and notifies the consumer terminal 5. This real-time response allows the consumer 51 to flexibly respond to changes in plans. The delivery guidance process S8 also provides additional information that the consumer 51 needs during the delivery procedure. For example, if there are any storage conditions or special handling methods for the aquatic organism, the distribution management server 202 includes that information in the guidance. This allows the consumer 51 to smoothly proceed through the process from receiving the aquatic organism to using it.

[0237] (Receiving Process S9) Next, receiving process S9 is executed to assist the consumer 51 in the procedure for receiving the reserved and purchased aquatic organism. The receiving process S9 is executed when the consumer 51 arrives at the distribution station 204 after passing through the delivery guidance process S8 and actually receives the aquatic organism.

[0238] Specifically, the distribution management server 202 verifies the transaction information recorded in the management database server 203 based on the delivery confirmation request received from the consumer terminal 5. This confirms whether the reserved aquatic creatures have been properly prepared and starts the delivery procedure. For example, when the consumer 51 receives two tiger pufferfish reserved at the "Higashi Ward Fisheries Center," the distribution management server 202 confirms the relevant transaction information and records on the system that the delivery preparations have been completed.

[0239] Furthermore, as the receiving procedure progresses, the distribution management server 202 communicates with the breeding management device 2041 of the distribution station 204 to confirm that the aquatic organisms have been secured under the specified conditions. At this time, it is preferable to refer to environmental data of the breeding tank 8 and condition data of the aquatic organisms to ensure that the aquatic organisms are of appropriate freshness and size. Furthermore, during the receiving process, authentication information such as a delivery code or QR code (registered trademark) presented by the consumer 51 on-site is also verified. This ensures that the aquatic organisms are delivered to the legitimate consumer 51. Once authentication is complete, the distribution management server 202 records a delivery completion status in the management database server 203 and officially terminates the transaction.

[0240] After the aquatic life has been received, the distribution management server 202 sends a transaction completion notification to the consumer terminal 5. This notification includes details of the received aquatic life and a final confirmation of the transaction contents. The consumer 51 may also be sent a guide encouraging the consumer to provide a review or feedback.

[0241] (Aquatic Organism Distribution Management Method) The distribution management server 202 is configured to execute an aquatic organism distribution management method. Specifically, the aquatic organism distribution management method, which distributes aquatic organisms using a distribution station 204 that is installed in a distribution area where aquatic organism consumers 51 exist and that raises aquatic organisms in the treated water while denitrifying the water in breeding tanks 8 using the water purification device 100, includes a reception process S1 that receives inquiry information inquiring about the inventory status of aquatic organisms from the consumer terminal 5 of the consumer 51, and a distribution management information transmission process S5 that, upon receiving the inquiry information, reads out distribution management information including the installation location information and the aquatic organism information from the distribution management server 202 that stores installation location information indicating the installation location of the distribution station 204 and aquatic organism information including the type, size, and number of aquatic organisms being raised in the treated water of the distribution station 204, and transmits the readout distribution management information to the consumer terminal 5.

[0242] According to the above configuration, distribution stations 204 capable of storing aquatic organisms in a fresh state are installed within the distribution area, allowing consumers 51 within the distribution area to obtain aquatic organisms in a state that maintains their freshness in a shorter time than if they were to purchase them from a fishing port or central wholesale market. Furthermore, consumers 51 can ascertain the location of distribution stations 204 and the type, size, and stock status of the aquatic organisms through their own consumer terminals 5. This allows consumers 51 to easily find the aquatic organisms they want and obtain them in a short time.

[0243] In addition, when the distribution management information includes location information of the consumer terminal 5, it is preferable that the distribution management information transmission process S5 includes the distance between the consumer terminal 5 and the distribution station 204 in the distribution management information based on the location information and the installation location information of the distribution station 204.

[0244] According to the above configuration, the distribution management server 202 acquires the location information of the consumer terminal 5, calculates the distance between the consumer terminal 5 and the distribution station 204 based on the location information and the installation location information of the distribution stations 204 installed in multiple locations, and transmits the distance information to the consumer terminal 5 as distribution management information. This allows the consumer 51 to check, via his or her own terminal, the location and distance of the distribution station 204 closest to his or her current location. Based on this information, the consumer 51 can select the optimal purchasing location that minimizes travel time and costs to obtain the desired aquatic organisms.

[0245] Furthermore, in addition to the reception process S1 and distribution management information transmission process S5 of Figure 12, the aquatic organism distribution management method may include at least one of the following: installation location information and aquatic organism information acquisition process S2, location information acquisition process S3 of the consumer terminal 5, distance information calculation process S4, aquatic organism selection and reservation process S6, payment process S7, delivery guidance process S8, and receipt process S9.

[0246] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the above-described embodiments. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described.

[0247] REFERENCE SIGNS LIST 1 Denitrification device 2 Nitrification device 3 Rearing control device 4 Monitoring device 6 Denitrification filter material 7 Air bubbles 8 Rearing tank 11 Denitrification tank 12 First rearing water supply channel 13 Denitrification air supply mechanism 14 Rearing water recovery channel 15 Liquid level gauge 21 Nitrification tank 22 Second rearing water supply channel 23 Third rearing water supply channel 24 Nitrification air supply mechanism 5 Consumer terminal 51 Consumer 52 Administrator 100 Water purification device 200 Aquatic organism distribution management system 201 Communication device 202 Distribution management server 203 Management database server 204 Distribution station 205 Seller terminal 206 Internet 2041 Rearing management device

Claims

1. A denitrification filter material composed of a biodegradable melt-kneaded resin composition containing (A) a water-insoluble and / or sea-water-insoluble resin component that is biodegradable, and (B) a biomass polysaccharide polymer component.

2. The denitrification filter medium according to claim 1, wherein component (A) is an ester-bonded polymer.

3. The denitrification filter medium according to claim 1, wherein component (A) comprises one or more selected from the group consisting of polybutylene succinate adipate, polyhydroxyalkanoate, and polycaprolactone.

4. The denitrification filter medium according to claim 1, wherein component (B) comprises a biomass polysaccharide polymer component having a helical molecular structure.

5. A water purification device comprising: a denitrification tank to which water to be treated is supplied; a denitrification filter material according to any one of claims 1 to 4 contained in the denitrification tank and adapted to settle aerobic denitrifying bacteria that reduce nitrate nitrogen in the water to be treated; and an air supply mechanism for supplying air to the water to be treated.

6. A water purification system comprising: a denitrification tank to which water to be treated is supplied; a denitrification filter material according to claim 1 housed within the denitrification tank and adapted to settle aerobic denitrifying bacteria that reduce nitrate nitrogen in the water to be treated; and a denitrification air supply mechanism disposed at the bottom of the denitrification tank and adapted to continuously perform an oxygen intake operation by supplying air to the water to be treated stored in the denitrification tank at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, thereby exposing the denitrification filter material to the air, thereby promoting the denitrification reaction by the denitrifying bacteria under aerobic conditions.

7. A water purification device as described in claim 6, which has an air flow regulating member arranged above the air discharge section of the denitrification air supply mechanism, which regulates the flow direction of the upward flow of air supplied from the air discharge section to the water to be treated and concentrates it in one place, thereby circulating the water to be treated and the denitrification filter material throughout the entire denitrification tank.

8. The water purification device according to claim 6, further comprising a nitrifying filter medium accommodated in the denitrification tank for establishing aerobic nitrifying bacteria that oxidize ammonium nitrogen in the water to be treated.

9. A water purification device as claimed in claim 1, comprising: a nitrification tank to which the water to be treated is supplied; a nitrification filter medium contained within the nitrification tank for establishing aerobic nitrifying bacteria that oxidize ammonia nitrogen in the water to be treated; and a nitrification air supply mechanism disposed at the bottom of the nitrification tank for continuously performing an oxygen intake operation by supplying air to the water to be treated stored in the nitrification tank at a volumetric rate of 50% to 5000% per minute of the storage volume of the water to be treated, thereby exposing the nitrification filter medium to the air, thereby promoting the nitrification reaction by the nitrifying bacteria under aerobic conditions.

10. A water purification device as described in claim 9, further comprising an air flow regulating member disposed above the nitrification air supply mechanism, which regulates the flow direction of the upward flow of air supplied from the nitrification air supply mechanism to the water to be treated and concentrates it in one location, thereby circulating the water to be treated and the nitrification filter material throughout the nitrification tank.

11. An aquatic organism distribution management system having a distribution station installed in a distribution area where consumers of aquatic organisms exist, where the treated water in a breeding tank is denitrified using the water purification device described in claim 6 or 9, while the aquatic organisms are raised in the treated water.

12. An aquatic life distribution management system as described in claim 11, comprising: a distribution management server that stores installation location information indicating the installation location of the distribution station and aquatic life information including the type, size, and number of the aquatic life being raised in the treated water at the distribution station; and a communication device that can send and receive distribution management information including the installation location information and the aquatic life information between the distribution management server and the consumer terminal of the consumer.

13. An aquatic life distribution management system as described in claim 12, wherein the distribution stations are installed at multiple locations, and when the distribution management information includes location information of the consumer terminal, the distribution management server includes the distance between the consumer terminal and the distribution station in the distribution management information based on the location information and installation location information of the distribution station.

14. The aquatic life distribution management system described in claim 12, wherein the communication device is capable of transmitting and receiving the distribution management information between the distribution management server and a seller terminal of a seller who sells the aquatic life using the distribution station, and the distribution management server includes replenishment information in the distribution management information and transmits it to the seller terminal when the number of aquatic life stored at the distribution station is below a predetermined number.

15. An aquatic organism distribution management method for distributing aquatic organisms using a distribution station that is installed in a distribution area where consumers of aquatic organisms exist and that raises aquatic organisms in treated water from breeding tanks while denitrifying the treated water using the water purification device described in claim 6 or 9, the method comprising: a reception process for receiving inquiry information inquiring about the inventory status of the aquatic organisms from the consumer terminal of the consumer; and a distribution management information transmission process for, when the inquiry information is received, reading distribution management information including installation location information indicating the installation location of the distribution station and aquatic organism information including the type, size, and number of the aquatic organisms being raised in the treated water at the distribution station from a distribution management server that stores the installation location information and the aquatic organism information, and transmitting the distribution management information to the consumer terminal.

16. The aquatic organism distribution management method described in claim 15, wherein the distribution management information transmission process, when the distribution management information includes location information of the consumer terminal, includes the distance between the consumer terminal and the distribution station in the distribution management information based on the location information and installation location information of the distribution station.

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