How to purify water in an aquarium where aquatic animals are kept

Abstract

To provide a water purification method for a water tank which is simplified, does not require running cost, and does not have to use a chemical material thereby preventing an adverse effect on aquatic animals.SOLUTION: There is provided a water purification method for a water tank 11 with aquatic animals A cultured therein, the method being configured to: draw part of water in the water tank with aquatic animals cultured therein; remove dissolved ammonia by heating the part of water and / or performing ultrasonic processing; and return the water from which dissolved ammonia is removed to the water tank with aquatic animals cultured therein. There is also provided a culture device 01 for aquatic animals used in the water purification method, the culture device 01 for aquatic animals comprising: a water tank for culturing aquatic animals A; a drawing pump 13 for drawing water in the water tank; a water treatment device 12 having a heater 12a and / or an ultrasonic transmitter 12b; a fluid feeding pump 14 for feeding water which is heated and from which dissolved ammonia is removed; and a cooling device 16 for performing forced cooling or natural cooling.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for purifying water in an aquarium where aquatic animals are kept, and more particularly to a water purification method that removes dissolved ammonia from the water using a specific method, and to an aquatic animal breeding device used in the water purification method. [Background technology]

[0002] Several techniques are known for removing dissolved ammonia from water used to raise fish. Known methods for removing ammonia include contacting or passing the water through a porous or adsorbent material, adding bacteria or chemicals to the water, using ozone, or passing electricity through the water.

[0003] As an example of the above-mentioned "method of bringing water into contact with or passing it through a porous or adsorbent material," Patent Document 1 describes a method in which the water is brought into contact with or filtered through ceramic, and then ammonia is converted into nitrite or nitrate. Furthermore, Patent Document 2 describes a method in which ammonium ions are decomposed by applying an electric current and then treated with activated carbon. Furthermore, Patent Document 5 describes a method in which, after ozone treatment, the material is treated with bakuhan stone, which is porous and has a specific particle size.

[0004] As an example of the above-mentioned "method of adding bacteria to water," Patent Document 3 describes a method of reducing the concentration of ammonia and ammoniacal nitrogen components using nitrifying bacteria. Furthermore, Patent Document 8 describes a method for eliminating the putrid odor of water in a tank by using activated sludge containing denitrifying bacteria.

[0005] As an example of the above-mentioned "method of adding a chemical substance to water," Patent Document 4 describes a method of adding an active chlorine species such as hypochlorous acid, measuring the ammonia concentration, and adjusting the water. Furthermore, Patent Document 8 describes a method in which a hydrogen donor is supplied to activated sludge for treating water, thereby preventing the generation of putrid odors without creating a blocked field. Furthermore, Patent Document 9 describes a denitrification treatment device that uses a denitrification material containing sulfur, carbonate, and a surfactant and has a circulation flow path.

[0006] Patent Documents 5, 6 and 7 describe the above-mentioned "method using ozone" and describe a method for purifying aquaculture water.

[0007] As the above-mentioned "method of passing electricity through water," Patent Document 2 describes a method of disposing a cathode and an anode in water and passing electricity through them to decompose ammonium ions.

[0008] However, the above-mentioned "method of bringing water into contact with or passing it through a porous or adsorbent material" is troublesome and disadvantageous in terms of cost because it requires replacing the "porous or adsorbent material" to which ammonia or ammonia-derived substances have adhered or adsorbed.

[0009] Furthermore, in the "method of adding bacteria or chemical substances to water," foreign matter is mixed into or dissolved in the water in which the aquatic animals are kept, affecting the aquatic animals. Furthermore, the bacteria or chemical substances may need to be added, and adjusting the concentration in the water is extremely troublesome. Furthermore, the use of the bacteria or chemical substances increases costs.

[0010] Furthermore, in the method using ozone, ozone is difficult to handle because it is harmful, and therefore cannot be used at home. Furthermore, the method of applying electricity is dangerous and has little effect on removing ammonia. Furthermore, ozone treatment and electrification inevitably have adverse effects on aquatic animals.

[0011] Against this background, there has been a demand for a "method for purifying water in aquariums where aquatic animals are kept" that is simple, does not require running costs such as replacing materials, and does not use "substances that have an effect on aquatic animals," such as chemicals. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 10-178966 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-104957 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-159244 [Patent Document 4] Japanese Patent Application Laid-Open No. 2004-160349 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-073458 [Patent Document 6] Japanese Patent Application Laid-Open No. 2017-063670 [Patent Document 7] Japanese Patent Application Publication No. 2017-176046 [Patent Document 8] Japanese Patent Application Publication No. 2019-180292 [Patent Document 9] Patent Publication No. 2021-079321 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made in view of the above-mentioned background art, and an object of the present invention is to provide a "method for purifying water in an aquarium in which aquatic animals are kept" that is simple, does not require running costs, and does not require the use of chemical substances and therefore does not adversely affect the aquatic animals. [Means for solving the problem]

[0014] As a result of extensive research into solving the above problems, the inventors discovered that ammonia (including ammonium ions) excreted by aquatic animals and bacteria in aquariums undergoes a chemical reaction in the water to produce nitrogen-containing organic compounds, which have an adverse effect on aquatic animals. The present inventors have found that removing dissolved ammonia is extremely effective in eliminating this adverse effect. Furthermore, they have found that heat treatment and / or ultrasonic treatment are capable of continuous treatment, require simple equipment, and are extremely effective in removing dissolved ammonia, leading to the completion of the present invention.

[0015] That is, the present invention provides a method for purifying water in an aquarium in which aquatic animals are kept, comprising the steps of: removing a portion of the water from the aquarium in which the aquatic animals are kept, and subjecting the portion of the water to heat treatment and / or ultrasonic treatment to remove dissolved ammonia; The water from which the dissolved ammonia has been removed is returned to the aquarium in which the aquatic animals are kept.

[0016] The present invention also provides a method for purifying water, which comprises continuously removing water from the aquarium, subjecting the removed water to a heat treatment and / or ultrasonic treatment to remove dissolved ammonia from the water, and returning the water from which the dissolved ammonia has been removed to the aquarium.

[0017] The present invention also provides a method for purifying water used for keeping pets, aquaculture, or aquariums.

[0018] The present invention also provides the above-mentioned method for purifying water, which reduces or detoxifies nitrogen-containing organic compounds produced by chemical reaction of the dissolved ammonia in the aquarium.

[0019] The present invention also provides a breeding apparatus for aquatic animals used in the water purification method, comprising: The present invention provides an aquatic animal breeding device comprising an aquarium for breeding aquatic animals, an extraction pump for extracting water from the aquarium, a water treatment device equipped with a heater and / or an ultrasonic transmitter, a liquid delivery pump for delivering water that has been heated to remove dissolved ammonia, and a cooling device for forced or natural cooling.

[0020] The present invention also provides a water treatment device that is used in a breeding device for aquatic animals that is used in the water purification method. [Effects of the Invention]

[0021] According to the present invention, problems such as illness and death of aquatic animals can be solved in an extremely simple manner. In the present invention, it was discovered that nitrogen-containing organic compounds generated by chemical reactions of dissolved ammonia in water act as poisons to the aquatic animals (have adverse effects on the aquatic animals) (see Examples). Therefore, by removing ammonia (including ammonium ions), which is the raw material (starting material) of the nitrogen-containing organic compounds, the present invention can eliminate the root cause of the problem, and can extremely effectively protect aquatic animals kept in the water from illness, death, etc. (see Examples). Hereinafter, ammonia or ammonium ions present in water will be abbreviated simply as “dissolved ammonia.” Additionally, “heat treatment and / or ultrasonic treatment” may be abbreviated simply as “heating, etc.”

[0022] Furthermore, the present invention was made based on the fact that "heat treatment and / or ultrasonic treatment happened to be extremely effective in removing dissolved ammonia from water." In other words, the present invention was made based on the combination of "the fact that removing ammonia is extremely effective for the health of aquatic animals" and "the existence of an extremely effective and simple method for removing dissolved ammonia." According to the present invention, it is possible to very simply and effectively suppress the production in an aquarium of "nitrogen-containing organic compounds that are generated by chemical changes of dissolved ammonia" which act as poisons to aquatic animals.

[0023] In the present invention, all of the water in the aquarium is not simultaneously heat-treated (i.e., the rearing water is not prepared in advance), and so the method is completely different from thermal sterilization of rearing water. In fact, with the method of the present invention, which involves continuous treatment or partial extraction and treatment, the number of bacteria in the entire water in the aquarium does not decrease (see Examples). This is because bacteria remaining in the aquarium are constantly multiplying. Therefore, when carrying out the present invention, the prior art techniques relating to heat sterilization and sterilization treatment of rearing water are of no use at all.

[0024] The present invention does not require the use of consumables such as adsorbents, carriers, porous materials, and filter media, including activated carbon, zeolite, bakuhan stone, and filters, and therefore eliminates the need for replacing these consumables. Furthermore, the cost of these consumables is unnecessary, resulting in a significant reduction in operating costs.

[0025] Furthermore, the apparatus used in the present invention is extremely simple in that it requires only the addition of a pump for extracting or supplying water and a water treatment device equipped with a heater and / or ultrasonic transmitter to a normal (minimum) rearing apparatus. This pump can also be used in combination with a pump for adding air (oxygen) to the water, so the water treatment device may be the only additional device required.

[0026] In the present invention, (a portion of) the water in the aquarium where the aquatic animals are actually kept is continuously extracted and purified (by heat treatment and / or ultrasonic treatment) before being returned to the original aquarium. In other words, continuous processing and automation of the equipment are possible during the breeding process. Therefore, if treatment is carried out continuously for a long period of time, it is only necessary to treat an extremely small amount of water per unit time, which simplifies the equipment and reduces operating costs.

[0027] According to the present invention, the use of chemical substances is not essential, and therefore no adverse effects on aquatic animals can be expected. Moreover, there is no risk of over-mixing of the chemical substances, and there is no need to analyze and manage the water in the aquarium where the aquatic animals are kept. In addition, the temperature of the water increases as it passes through the water treatment device, which also helps prevent the water from turning green due to algae growing in the tank.

[0028] Aquatic animals that live in freshwater, including fish, shrimp, and shellfish, excrete ammonia. In addition, whether it is freshwater or seawater, bacteria grow in large numbers in the water in which aquatic animals are kept, and these bacteria also excrete ammonia. The present invention is suitably applicable to aquatic animals that live in freshwater or seawater, such as fish, shrimp, and shellfish, and is also suitably applicable to aquatic animals that live in seawater, such as sea urchins, sea cucumbers, and sea squirts.

[0029] Therefore, combined with the above-mentioned advantages of being simple in terms of equipment, not producing consumables, and having low operating costs, the present invention is extremely suitable for use in pet breeding, aquaculture, and breeding in aquariums. Furthermore, according to the present invention, as described above, adverse effects on aquatic animals are eliminated, and dirt on the inner walls of the aquarium, cloudiness of the water, and algae growth are suppressed, resulting in favorable results for the appreciation of the aquatic animals. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a photograph showing the difference in turbidity of water in an aquarium three weeks after the start of the experiment in Example 1, depending on whether or not the water purification method of the present invention is used. [Figure 2] 1 is a photograph showing the difference in the concentration of ammonia contained in water three weeks after the start of the experiment, depending on whether or not the water purification method of the present invention is used. [Figure 3] 1 is a photograph showing the difference in the number and types of bacteria contained in water one week after the start of the experiment, depending on whether or not the water purification method of the present invention was used. [Figure 4] This is a photo of the "compounds that absorb light in the ultraviolet region" that were formed in the water two weeks after the start of the experiment, confirmed by spectroscopic analysis. [Figure 5]These are photographs of compounds that absorb in the ultraviolet region that were produced in the water three weeks after the start of the experiment, confirmed by thin-layer chromatography. (a) Confirmed by UV irradiation. (b) Confirmed by spraying with ninhydrin solution. [Figure 6] This photograph confirms that the compounds produced in the water two weeks after the start of the experiment are toxic to silkworms. [Figure 7] 1 is a conceptual diagram showing an example of the "aquatic animal breeding device" of the present invention. [Figure 8] 1 is a conceptual diagram showing an example of the "aquatic animal breeding device" of the present invention. [Figure 9] 1 is a conceptual diagram showing an example of the "aquatic animal breeding device" of the present invention. [Figure 10] 1 is a graph showing the change over time (number of days) in dissolved ammonia (mg / L) in water from a household-sized aquarium when heat-treated at 80°C in Example 2. [Figure 11] These are photographs showing the difference in the condition of Yamato shrimp depending on whether or not the water in the tank was heated. (a) Heat-treated (b) No heat treatment DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described below, but the present invention is not limited to the following specific embodiments and can be modified as desired within the scope of the technical concept.

[0032] The water purification method of the present invention is a method for purifying water in an aquarium in which aquatic animals are kept, comprising the steps of: removing a portion of the water from the aquarium in which the aquatic animals are kept, and subjecting the portion of the water to heat treatment and / or ultrasonic treatment to remove dissolved ammonia; The water from which the dissolved ammonia has been removed is returned to the aquarium in which the aquatic animals are kept.

[0033] <Aquatic animals> The aquatic animal A may be an animal that lives in freshwater, i.e., an animal that is kept in freshwater, an animal that lives in seawater, i.e., an animal that is kept in seawater, or an animal that lives in brackish water, i.e., an animal that is kept in brackish water. In the present invention, "water" includes freshwater, seawater, and brackish water.

[0034] The above-mentioned freshwater animals are not limited to those used for decoration or as food, and examples thereof include ornamental fish such as tropical fish, goldfish, killifish, and arowana; edible fish such as carp, char, trout, yamame trout, and loach; reptiles such as turtles; amphibians such as frogs and salamanders; shrimp such as Yamato swamp shrimp, southern swamp shrimp, red fire shrimp, and red lure shrimp; shellfish such as pond snails, stone snails, and kanoko shells; crabs; and the like. Furthermore, examples of the animals that live in seawater include, but are not limited to, ornamental or edible fish, shrimp, shellfish, crabs, starfish, sea urchins, sea cucumbers, sea squirts, hermit crabs, and the like.

[0035] Ammonia is excreted not only by fish but also by animals that live in freshwater. Ammonia is also excreted by bacteria in both freshwater and seawater. According to the present invention, ammonia can be removed not only from freshwater but also from seawater by heating etc. Also, ammonia can be removed from ammonium salts by heating etc.

[0036] Therefore, a preferred embodiment of the present invention is the method for purifying water, wherein the dissolved ammonia is ammonia excreted by aquatic animals kept in the aquarium or ammonia excreted by bacteria grown in the aquarium.

[0037] Specific examples of the aquarium 11 include aquariums for home use or for raising pets; aquariums for exhibition or breeding in aquariums, zoos, etc.; fish tanks, ponds, or aquariums for raising aquatic animals A for aquaculture or for food; and the like. That is, a preferred embodiment of the present invention is the above-mentioned method for purifying water used for keeping pets, aquaculture, or aquariums.

[0038] <Part of the water in the tank is removed and treated, for continuous treatment> The present invention is characterized in that a portion of the water W is extracted from the aquarium 11 in which the aquatic animal A is kept, and the portion of the water W is subjected to heat treatment and / or ultrasonic treatment to remove dissolved ammonia, and then returned to the aquarium 11 in which the aquatic animal A is kept. As shown in the examples, by removing a portion of the water W from the aquarium 11 and heating it or the like to remove the dissolved ammonia, and then returning that portion of the water W to the aquarium 11, and repeating this process, dissolved ammonia can be removed from the water W in which the aquatic animals A are actually being kept, without having to move or separate the aquatic animals A (see examples).

[0039] As shown in the examples, the dissolved ammonia was successfully removed by the above-mentioned procedure, and it is clear that continuous treatment of the breeding water W and automation of the treatment are possible. That is, the present invention is also a method for purifying water, which continuously involves withdrawing water from the water tank 11, removing dissolved ammonia from the water W by heating and / or ultrasonically treating the withdrawn water W, and returning the water W from which the dissolved ammonia has been removed to the water tank 11. Examples of embodiments suitable for continuous processing and automation are shown in Figures 7, 8 and 9. These will be explained later in the explanation of "aquatic animal breeding apparatus."

[0040] <Heat treatment and / or ultrasonic treatment> In the present invention, the heating is preferably carried out at a temperature of 60° C. or higher and 100° C. or lower. This temperature range allows for the effective removal of dissolved ammonia. The above "100° C." includes boiling (simmering). Ammonia in the water W is easily removed from the system (can be removed from the water) by raising the temperature of the water W. The heating temperature is more preferably 70°C or higher and 98°C or lower, even more preferably 75°C or higher and 96°C or lower, and particularly preferably 80°C or higher and 94°C or lower. If the lower limit of the temperature is too low, the removal of ammonia may be slow, while if the upper limit of the temperature is too high, evaporation of water may become a problem, power may be wasted, etc. Avoiding excessive evaporation of water is particularly preferable when the water W is seawater. Although boiling is included in the present invention, it is preferable not to boil the water W in view of evaporation of the water W and wasted electricity.

[0041] For example, ammonia can be removed by performing only ultrasonic treatment at room temperature (without heat treatment). In the present invention, dissolved ammonia is removed by heating and / or ultrasonic treatment of water W in water tank 11. Although heat treatment or ultrasonic treatment is essential, heat treatment and ultrasonic treatment are preferred for the purpose of simplifying the equipment and process and for efficient removal of ammonia, and heat treatment alone is particularly preferred. When heat treatment and ultrasonic treatment are carried out, they can be carried out separately or simultaneously.

[0042] <Dissolved ammonia concentration> The dissolved ammonia in the water immediately after heating or the like (ammonia in the water after some treatment) is preferably 5 mg / L or less, more preferably 1 mg / L or less, and particularly preferably 0.01 mg / L or more and 0.5 mg / L or less. Furthermore, when a portion of the water is withdrawn for treatment or treated continuously, the ammonia concentration in the water in the water tank 11, which is withdrawn and returned to circulate and maintain a steady state, is preferably 15 mg / L or less, more preferably 10 mg / L or less, and particularly preferably 0.01 mg / L or more and 5 mg / L or less.

[0043] If the dissolved ammonia concentration is too high, the aquatic animals may die or become sick, and the breeding water W in the aquarium 11 may become cloudy. On the other hand, if the dissolved ammonia concentration is reduced too much, the treatment may be wasteful and require additional costs and equipment.

[0044] <Forced cooling or natural cooling> In the present invention, it is preferable that the water W from which the dissolved ammonia has been removed is cooled by forced cooling or natural cooling, and then returned to the water tank 11 again. The water W that has been subjected to the heat treatment is cooled and then returned to the water tank 11, and it is preferable that the water W be returned to the water tank 11 after the temperature of the water W is brought to approximately the same as that of the water W remaining in the water tank 11. The cooling is performed by forced cooling or natural cooling. The cooling is preferably performed by a cooling device 16. When the cooling is natural cooling, a dedicated cooling device 16 may be used, or the piping, reservoir tank 17, etc. may also serve as the cooling device 16. In other words, the liquid may be cooled naturally while passing through or staying (storing) in the piping, reservoir tank 17, etc. The reservoir tank 17 is also preferably equipped with a water level sensor 12c and a water temperature sensor 12d.

[0045] <Nitrogen-containing organic compounds> The present invention has discovered that substances produced (resulting from chemical changes) when dissolved ammonia reacts chemically in the aquarium 11 have adverse effects on aquatic animals in the water and make the breeding water W cloudy (see Examples). Since this substance has absorption in the ultraviolet region, it is not ammonia but an organic substance, and since this organic substance becomes colored by the ninhydrin reaction, it is a nitrogen-containing organic compound such as an amine compound (see Examples).

[0046] Therefore, the present invention also relates to the above-mentioned water purification method, characterized in that nitrogen-containing organic compounds produced by chemical reaction of dissolved ammonia in the water tank 11 are detoxified or reduced in amount. In water that has been treated by heating or the like, aquatic animals A kept in the water are healthy (see Examples). The present invention also provides the above-mentioned water purification method, characterized in that dissolved ammonia is removed by the above-mentioned treatment (heating, etc.), thereby reducing nitrogen-containing organic compounds that are produced by chemical reactions of ammonia in the water tank 11.

[0047] <Aquatic animal breeding equipment> The device used in the present invention is a breeding device 01 for aquatic animals A used in the above-mentioned "water purification method," and preferably has an aquarium 11 for breeding the aquatic animals A and a water treatment device 12 equipped with a heater 12a and / or an ultrasonic transmitter 12b. Furthermore, by adding a pump and a cooling device 16, the present invention also provides a breeding device 01 for an aquatic animal A used in the above-mentioned "water purification method," characterized in that it comprises an aquarium 11 for breeding the aquatic animal A, an extraction pump 13 for extracting water W from the aquarium 11, a water treatment device 12 equipped with a heater 12a and / or an ultrasonic transmitter 12b, a liquid delivery pump 14 for delivering water W that has been heated to remove dissolved ammonia, and a cooling device 16 for forced or natural cooling.

[0048] 7, 8 and 9 show examples of the "aquatic animal breeding device" of the present invention. The water treatment device 12 in FIG. 7 includes a heater 12a and an ultrasonic generator 12b, and performs heat treatment with the heater 12a while irradiating ultrasonic waves. 8 and 9, the water treatment device 12 may include a heater 12a and a heating tank for storing water for heat treatment W. When an ultrasonic transmitter 12b is used in combination, the ultrasonic transmitter 12b is preferably provided at the bottom of the heating tank or the like so as to be immersed in the stored heated water. In Figure 9, a immersion heater is used and is immersed in the heating bath.

[0049] The type of heater 12a is not particularly limited, and examples include ceramic heaters, cast heaters, sheath heaters, IH heaters (electromagnetic induction heaters), cartridge heaters, electric resistance wire heaters such as nichrome wire, (transparent) glass heaters, hot plates, panel heaters, band heaters, etc. (there may be some overlap).

[0050] In Fig. 8, there is an exhaust port 12e at the top of the heating tank, and a water level sensor 12c and a water temperature sensor 12d are provided. The water level sensor 12c and the water temperature sensor 12d are connected to a control computer so that the water level and the water temperature can be adjusted, respectively.

[0051] The type of heater 12a, the necessity (presence) and type of heating tank, ultrasonic transmitter 12b, etc. of such water treatment device 12 are determined taking into consideration the purpose and scale, such as pet breeding (home use), aquaculture (commercial use), breeding in an aquarium, etc.

[0052] The type of pump is not particularly limited, and a conventional pump can be used. The number of pumps is not particularly limited as long as it is one or more, and examples thereof include an extraction pump 13 for extracting water from the water tank 11, a liquid delivery pump 14 for delivering water from the water treatment device 12, and a return pump 15 for returning the cooled water W to the water tank 11. Some of these pumps may be omitted or may be used in combination. In FIG. 9, a tube pump (Peristaltic Pump (registered trademark)) is used as the extraction pump 13 and the liquid feed pump 14. The necessity (number) and type of such pumps are determined taking into consideration the purpose, scale, etc.

[0053] The cooling device 16 is not particularly limited, and examples thereof include a cooling tower as shown in FIG. 8 and a radiator as shown in FIG. 9. The cooling method may be forced cooling or natural cooling. Also, it may be a water-cooling system or an air-cooling system. Furthermore, natural cooling while passing through a pipe may be utilized. The cooling device 16 and the cooling method are determined taking into consideration the purpose, scale, etc.

[0054] <Water treatment device for aquatic animal breeding equipment> The present invention also relates to a water treatment device 12 (equipped with a heater 12a, etc.) for use in the above-mentioned "apparatus for raising aquatic animals." In other words, the present invention also relates to a water treatment device 12 characterized by being used in "an apparatus for raising aquatic animals used in the above-mentioned 'water purification method.'"

[0055] The water treatment device 12 of the present invention can be added to an already owned general-purpose "aquatic animal breeding device" to be used as the breeding device 01 for the aquatic animal A. In other words, it is also possible to purchase only the water treatment device 12 of the present invention, which is sold for use in the "aquatic animal breeding device" of the present invention, and use it in combination with the breeding device that is already owned. [Example]

[0056] The present invention will be described in detail below based on examples, but the present invention is not limited to the specific scope of the following examples. Hereinafter, the term "%" means "% by mass" when it relates to mass.

[0057] Example 1 <Experiment> A 500 mL beaker (aquarium 11) was filled with 500 mL of deionized water W, and one goldfish measuring approximately 3 cm in body length was raised in the water. The water temperature was set to room temperature (25°C). Six beakers (aquarium 11) containing one goldfish each were prepared as a heat-treated group and a control group that received no treatment. Each treatment and control group was evaluated with n=6. Each fish was given 25 mg of food (Kyorin Goldfish Food, manufactured by Kyorin Co., Ltd.) every day.

[0058] Half the amount (250 mL) of the rearing water W in the beaker (aquarium 11) for the treatment group was removed every day and heated at 100°C for 3 minutes in a microwave oven. After that, it was left to cool to room temperature (25°C) and then returned to the original 250 mL of rearing water W containing one goldfish. The control group was simply given food and nothing was done.

[0059] <Mudgy water> One week after the start of the experiment, the water in the control group became visibly cloudy, whereas the water in the treated group remained transparent. Between three and five weeks after the start of the experiment, the water in the control group became increasingly cloudy, while the water in the treated group remained transparent. Figure 1 shows photographs of the treated and control groups after three weeks. Furthermore, five weeks after the start of the experiment, algae began to grow in the water of the control group, causing it to become increasingly green and cloudy, while the water of the treated group remained colorless and transparent.

[0060] <Simple analysis of dissolved ammonia> Dissolved ammonia was analyzed simply using commercially available test paper. Figure 2 shows photographs showing the ammonia concentrations in the treated and control groups three weeks after the start of the experiment.

[0061] Two weeks after the start of the experiment, an increase in ammonia levels was observed in the control group, whereas no increase in ammonia levels was observed in the treated group throughout the experiment.

[0062] <Types and numbers of bacteria in water> One week after the start of the experiment, water W in tank 11 was sampled using an agar plate and spread onto an agar medium. The plate was then cultured at 30°C for 24 hours, and the type and number of bacteria in the water were compared between the treatment group and the control group based on the shape and number of colonies that appeared. As shown in Figure 3, the results showed no significant differences between the treatment group and the control group in terms of the type and number of bacteria.

[0063] <Substances produced in water> <<Ultraviolet absorption spectrum>> The ultraviolet absorption spectra of the rearing water W of the treatment group and the control group were measured according to a conventional method. Figure 4 shows the ultraviolet absorption spectrum two weeks after the start of the experiment. The ultraviolet absorption of the rearing water W of the treatment group was lower than that of the rearing water W of the control group.

[0064] <<Thin-layer chromatography, ninhydrin reaction>> Two weeks after the start of the experiment, 240 mL of water from the treated and control groups was freeze-dried and developed by thin-layer chromatography (Merck TLC silica gel 60F254 plates) using a developing solvent of butanol:acetic acid:water = 4:1:2. Figure 5(a) shows a photograph after UV irradiation for detection, and Figure 5(b) shows a photograph after spraying with ninhydrin solution. In Figures 5(a) and 5(b), "mix" refers to a sample made by mixing the treated and control samples.

[0065] Although organic substances were detected, the amount of these organic substances was less in the treated group than in the control group, indicating that heat treatment reduces the amount of organic substances that absorb ultraviolet light. Furthermore, the organic substance was found to be a nitrogen-containing organic compound such as an amine compound (a compound having an amino group) because it was ninhydrin-positive (see FIG. 5(b)).

[0066] This result suggests that the amount of nitrogen-containing organic compounds generated can be reduced by heating a portion of the water W used to raise the goldfish at 100°C. It is believed that the heat treatment removed the "ammonia excreted from the goldfish" from the breeding water W, and suppressed the generation of organic matter by microorganisms present in the water W in the aquarium 11. In other words, in the treatment group, the content of dissolved ammonia in the beaker (water tank 11) was constantly decreasing due to the heating treatment of the partially extracted water W, and it is thought that the amount of organic substances (nitrogen-containing organic compounds) produced using the ammonia as a raw material also decreased.

[0067] <<Toxicity of organic substances produced from dissolved ammonia>> The silkworms used in the experiment were prepared as follows. Silkworm eggs (sold by Ehime Silkworm Seeds Co., Ltd.) were purchased and reared in the laboratory until the fifth instar larvae were used. Silkworms were reared at 27°C, and silkworms (on the third day of the fifth instar) that were fed artificial food for two days from the first day of the fifth instar were used in the experiment. The silkworms used in the experiment weighed approximately 2 g.

[0068] Two weeks after the start of the experiment, 240 mL of rearing water was removed from each of the treatment and control groups and freeze-dried. The freeze-dried material was dissolved in 5 mL of Milli-Q water ("MILLI-Q" is a registered trademark), and 50 μL of the solution was injected into the blood of each of the three silkworms.

[0069] Two days after injection, all silkworms injected with the control group died, while all silkworms injected with the treatment group survived (see Figure 6). It was found that the organic substances (nitrogen-containing organic compounds) produced from the dissolved ammonia in the beaker (aquarium 11) were toxic.

[0070] <Changes in Wakin> During the experimental period, 6 mice in the treatment group (n=6) and 5 mice in the control group (n=6) survived, but 1 mouse in the control group (n=6) died.

[0071] Example 2 <Results at a heating temperature of 80°C during continuous operation, and quantitative analysis of dissolved ammonia in the tank> The "aquatic animal breeding apparatus 01" shown in Figure 9 was constructed and operated continuously for 12 days, and the ammonia concentration in the aquarium water W was measured by the method described below. 9 L of water W was placed in a water tank 11 with a water surface of 42 cm x 27 cm, and 9 L of water W was also placed in a water treatment device 12, and the temperature of the water W in the water treatment device 12 was kept constantly at 80°C. The size of the water tank 11 and the volume of the water are approximately the same as the actual size (dimensions) when used at home.

[0072] Nine ringworms (2 g each) were placed in this tank 11. The water W was circulated at a rate of 1 L / hr using a pump 13. Each ringworm was given 0.15 g of food in three separate feedings. A commercially available activated carbon purifier was attached, and the ringworms were kept at room temperature (25°C) for 12 days. This was designated as "equipped with a heating (80°C) system."

[0073] A tank of the same size containing goldfish (18L of water) without a heat treatment function was prepared and used as the "Control (No treatment)."

[0074] <<Quantitative analysis of dissolved ammonia>> Dissolved ammonia was quantified using the "NH4 / NH3 test" manufactured by Cera Japan Co., Ltd. Ammonia water (28%) manufactured by Fujifilm Corporation was used as a standard reagent. After the reaction, the absorbance at 600 nm was measured, a calibration curve was created, and the ammonia concentration in the sample (in the water in the aquarium) was determined.

[0075] <<Results>> The results are shown in Figure 10. In the "Control (No treatment)," the dissolved ammonia concentration increased over time, but in the "with heating (80°C) system," no increase in the dissolved ammonia concentration was observed. In other words, in the actual machine, when a portion of the water W in the tank was extracted and continuously heated, the increase in the dissolved ammonia concentration in the water tank 11 was suppressed.

[0076] Furthermore, no deaths of the goldfish were observed during the above test period.

[0077] Example 3 <Rearing equipment for continuous processing (continuous operation), automation of processing> The "aquatic animal breeding apparatus 01" shown in Fig. 7 was used. Specifically, continuous treatment (operation) was carried out using the "aquatic animal breeding apparatus 01" shown in Figs. 8 and 9. Fresh water (deionized water) was used as the water W. A water tank 11 contained a ringworm.

[0078] The heat treatment was carried out at 80°C. As a control, when no heat treatment was performed, the heater 12a was turned off and only the water W was circulated in the same manner.

[0079] After 12 days, the rearing water that had not been heat-treated (the water of the control group) became cloudy, but the rearing water that had been heat-treated (the water of the treatment group) remained clear.

[0080] Example 4 When 10 Yamato marsh shrimp (average weight 0.2 g) were placed in the rearing water (water of the treatment group) that had been heat-treated in Example 3, all individuals were found to be alive and moving around energetically after 24 hours (see Figure 11(a)). In contrast, after 24 hours, all 10 Yamato shrimp in the breeding water that had not been heat-treated (control water) had turned red in body color and were confirmed to have died (see Figure 11(b)).

[0081] These results indicate that the ammonia produced by raising the goldfish killed the Yamato shrimp, but that when the ammonia was removed by heat treatment, an environment was created in which the Yamato shrimp could survive.

[0082] Example 5 <Cultivation in seawater> The removal of dissolved ammonia by heat treatment is the same for both freshwater and seawater, so it is thought that similar results will be obtained with seawater as with freshwater. [Industrial Applicability]

[0083] According to the present invention, the device and treatment method are simple, there are no running costs, and the use of chemicals is not required, so there is no adverse effect on aquatic animals. Therefore, the present invention can be widely used in the fields of development and manufacturing of materials and equipment for home ornamental use and pet breeding, etc.; education, entertainment and amusement fields such as aquariums and zoos; food production and aquaculture fields such as breeding of edible aquatic animals; water purification fields, etc. [Explanation of symbols]

[0084] 01 Breeding equipment 11 Water layer 12 Water treatment equipment 12a heater 12b Ultrasonic Transmitter 12c Water Level Sensor 12d Water temperature sensor 12e Exhaust port 13 Extraction pump 14 Liquid transfer pump 15 Return pump 16 Cooling device 17 Reservoir tank A Aquatic animals Water, breeding water

Claims

1. A method for suppressing the production of nitrogen-containing organic compounds in an aquarium in which aquatic animals are kept, comprising: a portion of the water in the aquarium in which the aquatic animals are kept is removed, and the portion of the water is heated at a temperature of 80°C or higher and 100°C or lower to remove dissolved ammonia; The method for inhibiting the production of nitrogen-containing organic compounds comprises returning the water from which the dissolved ammonia has been removed back into the aquarium in which the aquatic animals are kept, A method for inhibiting the production of nitrogen-containing organic compounds, characterized in that the number of bacteria in the entire water in the aquarium is not reduced.

2. 2. The method for inhibiting the formation of nitrogen-containing organic compounds according to claim 1, wherein the water from which the dissolved ammonia has been removed is cooled by forced cooling or natural cooling and then returned to the water tank.

3. 3. The method for inhibiting the production of nitrogen-containing organic compounds according to claim 1, wherein the steps of withdrawing water from the tank, removing dissolved ammonia from the water by heat treatment of the withdrawn water, and returning the water from which the dissolved ammonia has been removed to the tank are continuously carried out.

4. 4. The method for inhibiting the production of nitrogen-containing organic compounds according to claim 1, wherein the dissolved ammonia is ammonia excreted by aquatic animals kept in the aquarium, or ammonia excreted by bacteria grown in the aquarium.

5. 5. The method for inhibiting the formation of nitrogen-containing organic compounds according to claim 1, which is used for keeping pets, for aquaculture, or for keeping in an aquarium.

6. A method for inhibiting the production of nitrogen-containing organic compounds described in any one of claims 1 to 5, wherein the nitrogen-containing organic compound is an amine compound.

7. 7. A breeding apparatus for aquatic animals used in the method for inhibiting the production of nitrogen-containing organic compounds according to any one of claims 1 to 6, comprising: An aquatic animal breeding device comprising an aquarium for breeding aquatic animals, an extraction pump for extracting water from the aquarium, a water treatment device equipped with a heater, a liquid delivery pump for delivering water that has been heated to remove dissolved ammonia, and a cooling device for forced or natural cooling.

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