Aquaculture facility management methods

Abstract

The objective is to provide a simple method that does not require the installation of a device for supplying bubbles, and that does not require the complete draining of the water from the aquaculture pond beforehand, thus eliminating the need for further cleaning. [Solution] The above problem is solved by an aquaculture facility management method that includes the steps of: adding a peroxide or an aqueous solution of the peroxide to an aquaculture facility containing organic sediment and water; reacting the organic sediment etc. with the peroxide to generate bubbles; and using the generated bubbles to make at least a portion of the organic sediment etc. float to the surface.

Description

Technical Field

[0001] The present invention relates to a method for managing an aquaculture facility including floating organic sediments and the like.

Background Art

[0002] Patent Document 1 discloses a foreign matter removing means for removing organic substances that are floated along with bubbles by sending oxygen-containing bubbles into an aquaculture tank when culturing aquatic animals (Patent Document 1).

[0003] Further, Patent Document 2 discloses that an organic substance deposited and adhered to the bottom sand of an aquaculture pond can be quickly and surely peeled off and removed, and the organic substance adhered to the bottom sand can be quickly decomposed by using a hydrogen peroxide adduct or a peroxide dissolved in water (Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, Patent Document 1 requires a device to deliver oxygen-containing bubbles into the aquaculture tank, which presents a problem as it is difficult to install easily. Furthermore, the range of organic matter that can be removed by the bubbles generated by such a device is limited to the area around where the device is installed. Patent Document 2 describes a method for improving the bottom sand of an aquaculture pond, in which, after draining the freshwater or seawater from the pond, a chemical such as a hydrogen peroxide adduct that dissolves in water to produce hydrogen peroxide is brought into contact with the bottom sand to remove organic matter accumulated or attached to the bottom sand, and then the bottom sand is washed. However, this method has the problem that after draining all the water from the aquaculture pond, the chemical must be sprayed and brought into contact with the entire pond, and then the bottom sand must be washed. To solve these problems, there is a need for a simple method that does not require the installation of a device to send out bubbles, and that does not require further cleaning by draining all the water from the aquaculture pond beforehand. [Means for solving the problem]

[0006] The present invention provides a method for managing an aquaculture facility containing organic sediment and water, comprising the steps of: adding a peroxide or an aqueous solution of the peroxide; reacting the organic sediment and / or the water with the peroxide to generate bubbles; and using the bubbles to cause at least a portion of the organic sediment and / or the precipitate contained in the organic sediment to float to the surface. [Effects of the Invention]

[0007] The present invention makes it possible to move organic sediments and / or precipitates contained therein, which cause contamination of aquaculture facilities and diseases in the farmed fish, from the bottom of the aquaculture facility to the water or the water surface.

[0008] The following describes preferred embodiments for carrying out the present invention. The embodiments described below are merely examples of typical embodiments of the present invention, and the scope of the invention should not be narrowed by these embodiments. [Modes for carrying out the invention]

[0009] The method of the present invention is used in aquaculture facilities containing organic sediment and water. In this specification, "aquaculture facility" refers to all facilities for cultivating the fish and shellfish described below. That is, the category of aquaculture facilities includes all facilities for cultivating the above-mentioned fish and shellfish, which have traditionally been called aquaculture ponds or aquaculture pens, etc. The method of the present invention can be applied to any aquaculture facility without being limited by the location of the aquaculture facility, its size (area / volume), the type of water filling the facility (freshwater or seawater), etc. In the method of the present invention, land-based aquaculture facilities for eels and salmon and trout are preferred.

[0010] In aquaculture facilities where the method of the present invention is used (hereinafter also referred to as "aquaculture facilities of the present invention"), fish and shellfish are cultivated. In this specification, "fish and shellfish" means a general term for aquatic animals including fish and shellfish, and in particular means aquatic animals that are consumed by humans, such as fish, shellfish, shrimp, crabs, octopuses, squid, and sea urchins. Preferably, eels and salmon and trout.

[0011] The bottom of the aquaculture facility of the present invention may contain soil, stones, sand, etc., in addition to organic sediment. The organic sediment included in the aquaculture facility of the present invention (hereinafter also referred to as the organic sediment of the present invention) refers to the organic sediment accumulated at the bottom of the aquaculture facility. Furthermore, the organic sediment of the present invention may contain parasites, parasite eggs, parasite cysts, and / or microplastics as precipitates. Here, the organic sediment of the present invention is not limited to being completely solid, but may also include viscous substances.

[0012] The organic sediment of the present invention is not particularly limited as long as it is organic sediment that floats to the surface due to bubbles generated by the reaction of organic sediment and / or water with peroxides, as described later. Examples of such organic sediment include fish and shellfish feces, leftover feed, and diatoms associated with the aquaculture of the aforementioned fish and shellfish. Specifically, it refers to fish and shellfish feces, leftover feed, and diatoms associated with the aquaculture of the aforementioned fish, and more specifically, fish and shellfish feces and leftover feed associated with the aquaculture of eels and salmon and trout. By causing such fish and shellfish feces, leftover feed, and diatoms associated with aquaculture to float to the surface from the bottom of the aquaculture facility, or by causing them to float and be removed, it becomes easier to keep the aquaculture facility clean.

[0013] The parasites, parasite eggs, and parasite cysts contained in the precipitate are not particularly limited, as long as they are parasites, parasite eggs, and parasite cysts that float to the surface due to bubbles generated by the reaction of organic sediment and / or water with peroxides, as described later. Examples include the parasites that infest the aforementioned fish and shellfish, the eggs of the aforementioned parasites that infest the aforementioned fish and shellfish, and the cysts of the aforementioned parasites that infest the aforementioned fish and shellfish. Preferably, the parasites are those that infest the aforementioned fish, the eggs of those parasites, or the cysts of those parasites; more preferably, the parasites are those that infest eels and salmonids, the eggs of those parasites, or the cysts of those parasites; and particularly preferably, the parasites are Pseudodactylogyrus that infest eels, the eggs of Pseudodactylogyrus that infest eels and salmonids, Ichthyophthirius multifiliis that infests salmonids, or the cysts of Ichthyophthirius multifiliis that infest salmonids. Eels and salmonids are fish that can be farmed in similar aquaculture facilities, and the size of Pseudodactylogyrus that infest eels is about the same as that of Ichthyophthirius multifiliis and its cysts that infest salmonids. By bringing these parasites, their eggs, and cysts to the surface of the aquaculture facility, or by removing them after they have been brought to the surface, it becomes easier to prevent infection of the farmed fish with diseases.

[0014] The microplastics contained in the sediment are not particularly limited, as long as they are microplastics that float to the surface due to bubbles generated by the reaction of organic sediments and / or water with peroxides, as described later. Examples include microplastics already present in the water contained in the aquaculture facilities described later, especially natural seawater, as well as microplastics derived from blue sheets, feed bags, and greenhouses, etc. Microplastics in aquaculture facilities are either floating in the water of the aquaculture facilities, accumulated at the bottom of the facilities, or attached to organic sediments, and are therefore easily brought to the surface by bubbles generated by the reaction of organic sediments and / or water with peroxides, as described later. Examples of components of microplastics include polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0015] The water contained in the aquaculture facility of the present invention may be freshwater or seawater. Freshwater is not particularly limited, but examples include tap water, irrigation water, and groundwater. Seawater is not particularly limited, but examples include natural seawater and artificial seawater.

[0016] The height from the bottom of the aquaculture facility of the present invention to the surface of the water contained in the facility is not particularly limited, but it is preferable to keep it low from the viewpoint of reducing the amount of peroxide added, as described later. The height from the bottom of the aquaculture facility of the present invention to the surface of the water contained in the facility is, for example, twice or more the height from the bottom of the aquaculture facility to the surface of the organic sediment, preferably between twice and ten times, and more preferably between twice and five times. By having the height from the bottom of the aquaculture facility of the present invention to the surface of the water contained in the facility be twice or more the height from the bottom of the aquaculture facility to the surface of the organic sediment, it becomes easier to keep organic sediment, such as fish and shellfish feces and leftover feed, diatoms and / or precipitates contained in organic sediment, such as parasites, parasite eggs, parasite cysts, and microplastics (hereinafter also referred to as organic sediment, etc.), floating on the surface. Furthermore, if the height from the bottom of the aquaculture facility to the top of the organic sediment in the aquaculture facility is low, for example, 2 cm or less, the height from the bottom of the aquaculture facility to the top of the water contained in the aquaculture facility according to the present invention is, for example, 5 cm or more from the top of the organic sediment in the aquaculture facility, preferably 7.5 cm or more, and more preferably 10 cm or more. Even when the height from the bottom of the aquaculture facility to the top of the organic sediment in the aquaculture facility is low, by setting the height from the bottom of the aquaculture facility to the top of the water contained in the aquaculture facility to 5 cm or more from the top of the organic sediment in the aquaculture facility according to the present invention, it becomes easy to keep the organic sediment floating. Furthermore, in some aquaculture facilities, the water depth is not constant. For example, in some cases, the aquaculture facility is bowl-shaped and the water depth increases towards the center of the aquaculture facility. In such cases, the height from the bottom surface of the aquaculture facility of the present invention to the top surface of the water contained in the aquaculture facility is, for example, 2 times or more, preferably 2 times or more and 10 times or less, the height from the bottom surface of the aquaculture facility to the top surface of the organic sediment in the shallowest part of the area where organic sediment is present at the bottom of the aquaculture facility.Alternatively, in such a case, the height from the bottom of the aquaculture facility of the present invention to the top of the water contained in the aquaculture facility is, for example, twice or more the height from the bottom of the aquaculture facility to the top of the organic sediment in the portion of the organic sediment at the bottom of the aquaculture facility where the top of the organic sediment is at the highest position. Preferably, it is between twice and ten times, and more preferably between twice and five times. As a specific example, in a bowl-shaped aquaculture facility, the water level is about 5 cm from the top of the organic sediment at the shallowest point.

[0017] The peroxide used in the present invention (hereinafter also referred to as the peroxide of the present invention) is not particularly limited as long as it is a peroxide that reacts with water and / or organic deposits to generate bubbles. Examples of such peroxides include inorganic peroxides and organic peroxides.

[0018] Examples of inorganic peroxides include sodium percarbonate, sodium perborate, sodium peroxide, calcium peroxide, barium peroxide, hydrogen peroxide, sodium persulfate, potassium persulfate, and ammonium persulfate. Of these, hydrogen peroxide is preferred. Inorganic peroxides can be used individually or in combination of two or more.

[0019] Among the peroxides used in the present invention, hydrogen peroxide mainly refers to commercially available 3-60% aqueous hydrogen peroxide solutions for industrial use. Alternatively, hydrogen peroxide generated from a hydrogen peroxide supply compound or hydrogen peroxide generated by electrolysis of water or an alkaline solution can also be used. Examples of hydrogen peroxide supply compounds include inorganic peracids such as percarbonate, perboric acid, and peroxysulfuric acid, organic peracids such as peracetic acid, and their salts, which can release hydrogen peroxide in water. Examples of these salts include sodium percarbonate and sodium perborate. The above-mentioned hydrogen peroxide and hydrogen peroxide supply compounds may be diluted or dissolved in water to achieve the desired hydrogen peroxide concentration before use.

[0020] The organic peroxide is not particularly limited, but considering the usage environment of the present invention, it is preferable that it is highly hydrophilic. From this viewpoint, for example, an organic peroxide having 15 or fewer carbon atoms in total can be used, or for example, an organic peroxide having 10 or fewer carbon atoms, or for example, an organic peroxide having 8 or fewer carbon atoms can be used. The number of carbon atoms in the organic peroxide can also be, for example, 2 or more, or for example, 3 or more. The preferred range for the total number of carbon atoms in the organic peroxide can be set by appropriately combining the upper and lower limits described above, for example, 2 to 10, or for example, 2 to 8. Furthermore, while it is preferable that the organic peroxide is hydrophilic, for example, ketone peroxides, hydroperoxides, percarboxylic acids, diacyl peroxides, etc., generally tend to have high water solubility.

[0021] Examples of organic peroxides include diacyl peroxide, peroxy dicarbonate, peroxy ester, tetramethylbutyl peroxyneodecanoate, bis(4-butylcyclohexyl) peroxy dicarbonate, di(2-ethylhexyl) peroxy carbonate, butyl peroxyneodecanoate, dipropyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, diethoxyethyl peroxy dicarbonate, diethoxyhexyl peroxy dicarbonate, hexyl peroxy dicarbonate, dimethoxybutyl peroxy dicarbonate, bis(3-methoxy-3-methoxybutyl) peroxy dicarbonate, dibutyl peroxy dicarbonate, dicetyl peroxy dicarbonate, dimyristyl peroxy dicarbonate, and 1,1,3,3-tetramethylbutyl peroxypivale Examples include hexyl peroxypivalate, butyl peroxypivalate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxyneodecanoate, amyl peroxyneodecanoate, butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, amyl peroxypivalate, t-butyl peroxypivalate, t-amyl peroxy-2-ethylhexanoate, lauryl peroxide, dilauroyl peroxide, didecayl peroxide, as well as hydroperoxides such as t-butyl hydroperoxide, p-cumyl hydroperoxide, t-amyl hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide, percarboxylic acids such as peracetic acid and perbenzoic acid, methyl ethyl ketone peroxide, or benzoyl peroxide (benzoyl peroxide). In the present invention, preferred organic peroxides include hydroperoxides such as t-butyl hydroperoxide, p-cumyl hydroperoxide, t-amyl hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide; ketone peroxides such as methyl ethyl ketone peroxide; percarboxylic acids such as peracetic acid and perbenzoic acid; and diacyl peroxides such as benzoyl peroxide. Particularly preferred is peracetic acid. Furthermore, one or more organic peroxides can be used in combination.

[0022] Among the peroxides used in the present invention, peracetic acid can be used without particular limitation as a conventionally known product commercially available for industrial use. Peracetic acid can exist while maintaining an equilibrium state between hydrogen peroxide and acetic acid in an aqueous solution. Therefore, as the liquid containing peracetic acid, for example, a liquid composition having a composition of 6% by mass of peracetic acid, 32% by mass of acetic acid, 8% by mass of hydrogen peroxide and 54% by mass of water, and a liquid composition having a composition of 14 to 17% by mass of peracetic acid, 20 to 30% by mass of acetic acid, 10 to 15% by mass of hydrogen peroxide and 38 to 56% by mass of water can both be applied. The concentration of peracetic acid in the liquid containing peracetic acid can be measured by a conventionally known measuring method (for example, titration method).

[0023] The aquaculture facility management method according to the present invention includes a step of adding a peroxide or an aqueous solution of a peroxide to an aquaculture facility containing organic sediment and water. The aquaculture facility management method according to the present invention includes a step of generating bubbles by bringing a peroxide into contact with water and / or organic sediment, for example, feces and residual feed of seafood and diatoms associated with the above-mentioned aquaculture of seafood in an aquaculture facility containing organic sediment and water. Further, it includes a step of floating at least a part of the organic sediment or the like by the generated bubbles. The aquaculture facility management method including the step of generating bubbles having such characteristics and the step of floating by the bubbles makes it easy to float the organic sediment or the like deposited on the bottom of the aquaculture facility to the water of the aquaculture facility and maintain the floated state.

[0024] In the method for managing an aquaculture facility defined in the present invention, the terms "aquaculture facility", "water", "organic deposit", "sediment contained in the organic deposit", and "peroxide" have the same meanings as those of these terms described above, so overlapping explanations will not be repeated. Therefore, the "organic deposit" and "sediment contained in the organic deposit" that are to be floated by the method for managing an aquaculture facility according to the present invention are the same as those described in the above items. That is, the organic deposit floated by the above aquaculture facility management method is preferably feces and uneaten feed associated with the culture of eels and salmonids. Further, the sediment contained in the organic deposit floated by the above aquaculture facility management method is a parasite, an egg of a parasite, a cyst of a parasite, or microplastics. As the parasite, the egg of a parasite, and the cyst of a parasite, as described above, Pseudodactylogyrus parasitizing eels, eggs of Pseudodactylogyrus parasitizing eels, Ichthyophthirius parasitizing salmonids, and Ichthyophthirius parasitizing salmonids are particularly preferable. Examples of microplastics include microplastics already mixed in the water contained in the above aquaculture facility, particularly natural seawater, and microplastics derived from blue sheets, feed bags, vinyl greenhouses, and the like.

[0025] In the present invention, as a method for bringing peroxide into contact with an organic deposit, for example, feces and uneaten feed of fishery products associated with the above culture of fishery products, and diatoms, examples include a method of directly adding peroxide to an aquaculture facility containing an organic deposit and water, a method of adding an aqueous peroxide solution in which peroxide is dissolved in water to an aquaculture facility containing an organic deposit and water, and the like. Preferably, it is a method of adding an aqueous peroxide solution in which peroxide is dissolved in water to an aquaculture facility containing an organic deposit and water. The method of dissolving peroxide in water may be performed by a known method. The concentration when peroxide is dissolved in water may be appropriately determined according to the concentration of peroxide in the aquaculture facility of the present invention described later. Further, the water for dissolving peroxide may be fresh water or seawater. Fresh water and seawater are as described above.

[0026] In the bubble generation step of the present invention, the concentration of peroxide in the water of the aquaculture facility after adding peroxide or an aqueous peroxide solution to the facility is not particularly limited, but should be a concentration such that bubbles are generated when it reacts with the organic sediment of the present invention, such as fish and shellfish feces, leftover feed, diatoms, etc., associated with the cultivation of the aforementioned fish and shellfish. The upper limit of such a peroxide concentration may be, for example, 1000 mg / L or less, 750 mg / L or less, 500 mg / L or less, and 300 mg / L or less, and the lower limit may be, for example, 25 mg / L or more, 50 mg / L or more, 100 mg / L or more, 150 mg / L or more, and 200 mg / L or more. The upper and lower limit values ​​can be arbitrarily combined. For example, a combination of 25 mg / L or more and 1000 mg / L or less is preferred, preferably 50 mg / L or more and 750 mg / L or less, and more preferably 50 mg / L or more and 300 mg / L or less. If the peroxide concentration in the above-mentioned aquaculture facility falls below 25 mg / L, it may become impossible to generate bubbles from the organic sediment, or it may take an excessive amount of time to bring the organic sediment to the surface, potentially reducing work efficiency. However, in the process of generating bubbles, it is not ruled out to locally bring the peroxide into contact with the organic sediment in the aquaculture facility at a concentration exceeding the above-mentioned limit.

[0027] In the bubble generation step of the present invention, when the peroxide is brought into contact with the organic sediment of the aquaculture facility, it is preferable to leave the organic sediment in that state for at least 1 hour. When the peroxide is brought into contact with the organic sediment of the aquaculture facility, it is preferable to leave the organic sediment in that state for at least 3 hours, more preferably at least 6 hours, and even more preferably at least 12 hours. This allows for sufficient bubble generation effect on the organic sediment. Furthermore, the higher the concentration of the peroxide, the shorter the time the organic sediment is left in that state after contact with the peroxide is preferable (for example, 1 hour at 1000 mg / L), and the lower the concentration of the peroxide in the liquid, the longer the time the organic sediment is left in that state after contact with the peroxide is preferable (for example, 6 hours at 50 mg / L).

[0028] The method for adding the above-mentioned peroxide aqueous solution to the aquaculture facility is not particularly limited, but it may be added by known methods. Specifically, as a method for adding to the aquaculture facility in the present invention, the above-mentioned peroxide aqueous solution can be easily prepared by adding it together with fresh water or seawater to piping for introducing fresh water or seawater into the aquaculture facility, adjusting the amount so that the concentration of peroxide is, for example, 25 mg / L or more when it comes into contact with the organic sediment of the aquaculture facility. The number of addition points for adding the above-mentioned peroxide or peroxide aqueous solution to the aquaculture facility may be one or more. Even with just one addition point, since the aquaculture facility of the present invention contains water, the convection of the water and / or stirring described later makes it easy to permeate the peroxide throughout the aquaculture facility and bring the peroxide into contact with the organic sediment of the aquaculture facility.

[0029] The timing for adding the peroxide solution is not particularly limited, but examples include when the aquaculture target is in the aquaculture facility or when the aquaculture target has been recovered and is no longer in the aquaculture facility. From the viewpoint of using peroxide, it is preferable to add it when the aquaculture target is no longer in the aquaculture facility.

[0030] The aquaculture facility management method according to the present invention may further include a step of stirring the organic sediment of the aquaculture facility during or after the addition of peroxide or an aqueous solution of peroxide. By stirring the organic sediment, the organic sediment at the bottom of the aquaculture facility is diffused into the water, increasing the number of times the peroxide added to the aquaculture facility comes into contact with the organic sediment, thereby facilitating the reaction between the organic sediment and the peroxide.

[0031] The process of generating bubbles described above may further include a step of stirring the water in the aquaculture facility. By stirring the water, the concentration of peroxide in the part consumed in the reaction becomes uniform with that of the other parts, allowing the reaction to proceed more efficiently. In addition, if organic sediment is diffused into the water during stirring, the reaction with peroxide becomes easier, as described above.

[0032] Here, although the exact composition of the bubbles generated when organic deposits and peroxides come into contact is unknown, examples described later show that as the concentration of peroxides increases, the bubbles are generated more quickly and the amount of dissolved oxygen increases, suggesting that at least oxygen is present.

[0033] The flotation step of the present invention is a step of flotating organic sediments, etc., using the bubbles generated in the bubble generation step described above. Here, the organic sediments, etc. to be flotted may be flotted by bubbles generated when they themselves react with peroxides, or by bubbles generated when other organic sediments and water react with peroxides. In the present invention, flotation means that the organic sediments, etc. are floating in water, near the water surface, or on the water surface, and it is sufficient that the organic sediments, etc. are floating on the water and can be removed when water is discharged from the aquaculture facility described later.

[0034] In the flotation process of the present invention, there is a possibility that the flotated organic sediment may sink again. In this case, the water or peroxide aqueous solution described above may be added further so that the concentration of peroxide in the aquaculture facility does not fall below 25 mg / L. Furthermore, in the flotation process of the present invention, the concentration of peroxide in the aquaculture facility described above is as described above, and it is preferable to maintain that concentration until the removal process described later is started.

[0035] The aquaculture facility management method according to the present invention further includes a step of removing the organic sediment and the like that floated to the surface by the above-described floating step by draining the water from the aquaculture facility. Furthermore, the aquaculture facility management method according to the present invention further includes a step of adding water to the aquaculture facility containing the organic sediment and the like that floated to the surface by the above-described floating step, and then removing the water containing the organic sediment and the like that from the aquaculture facility by draining the water during or after the addition of water. By an aquaculture facility management method having such features and including a removal step, it is possible to prevent contamination of aquaculture facilities by organic sediment and microplastics, and infection and death of farmed animals by parasites.

[0036] The water addition in the aquaculture facility management method according to the present invention (hereinafter also referred to as "water addition in the present invention") involves adding water to the aquaculture facility containing the floating organic sediment and / or sediment contained in the organic sediment after the organic sediment and / or sediment contained in the organic sediment have been allowed to float. Here, the water added to the aquaculture facility may be freshwater or seawater. As freshwater, there are no particular limitations, but examples include tap water, water for irrigation, groundwater, etc. As seawater, there are no particular limitations, but examples include natural seawater, artificial seawater, etc.

[0037] The method of adding water to an aquaculture facility containing organic sediment, etc., is not particularly limited, but can be done by known methods. Examples of methods for adding water to an aquaculture facility in this invention include using piping for introducing freshwater or seawater into the facility. In the removal process of this invention, since this is a process after the organic sediment, etc., has been floated to the surface, the concentration of peroxides in the aquaculture facility may fall below 25 mg / L after the addition of water.

[0038] The height of the water in the aquaculture facility after adding water according to the present invention is not particularly limited, as long as it is not so high that the water overflows from the aquaculture facility. The height from the bottom surface of the aquaculture facility to the top surface of the water contained in the aquaculture facility after adding water (hereinafter also referred to as the height of the water after adding water according to the present invention) is, for example, twice or more, preferably four times or more, more preferably six times or more, even more preferably eight times or more, and particularly preferably ten times or more, the height from the bottom surface of the aquaculture facility to the top surface of the water contained in the aquaculture facility before adding water. If the height of the water after adding water according to the present invention is twice or more the height from the bottom surface of the aquaculture facility to the top surface of the water contained in the aquaculture facility before adding water, organic sediment and the like will be less likely to settle again on the bottom surface of the aquaculture facility, and organic sediment and the like that floated up during drainage will be easier to discharge. In addition, in some aquaculture facilities, the water depth is not constant. For example, in some cases, the aquaculture facility is bowl-shaped and the water depth increases towards the center of the aquaculture facility. In such cases, the water height after adding water according to the present invention is, for example, 2 times or more, preferably 4 times or more, more preferably 6 times or more, even more preferably 8 times or more, and particularly preferably 10 times or more, the height from the bottom of the aquaculture facility to the top of the water in the shallowest part of the aquaculture facility before adding water. As a specific example, in a bowl-shaped aquaculture facility, the water height after adding water is about 50 cm to 100 cm from the bottom of the aquaculture facility at the shallowest point.

[0039] The timing for initiating the addition of water in this invention is the same as, or longer than, the standing time when the peroxide is brought into contact with the organic sediment of the aquaculture facility in the bubble generation step described above. For example, the timing for initiating the addition of water in this invention is 1 hour or more after contact with the organic sediment of the aquaculture facility, preferably 3 hours or more, more preferably 6 hours or more, even more preferably 12 hours or more, and particularly preferably 24 hours or more. By leaving it for 1 to 24 hours or more after contact with the organic sediment of the aquaculture facility, it is possible to maintain a state in which the organic sediment to be removed from the aquaculture facility is floating. However, if left for more than 48 hours, the floating organic sediment may sink, so the upper limit is preferably 48 hours or less.

[0040] In one embodiment, the wastewater in the removal step of the aquaculture facility management method according to the present invention (hereinafter also referred to as the wastewater of the present invention) is discharged from the aquaculture facility without adding water after at least a portion of the organic sediment and / or the sediment contained in the organic sediment has been allowed to float to the surface. In another embodiment, the wastewater of the present invention is discharged from the aquaculture facility with water containing the floating organic sediment, etc., either during or after the addition of water as described above in the present invention.

[0041] The wastewater discharge method of the present invention is not particularly limited to a method of discharge only from the bottom of the aquaculture facility. Examples of the wastewater discharge method of the present invention include a method of discharge from the side of the aquaculture facility, a method of discharge using a pump, etc., and among these, the method of discharge from the side of the aquaculture facility is preferred. Furthermore, if the amount of wastewater discharged from the bottom of the aquaculture facility is less than that of other discharge methods, the wastewater discharge method of the present invention may be combined with a method of discharge from the bottom of the aquaculture facility.

[0042] The timing for initiating the drainage according to the present invention is not particularly limited. If water is not added, the drainage time is the same as, or longer than, the time the peroxide is left in contact with the organic sediment of the aquaculture facility during the bubble generation process described above. If water is added, the drainage may be initiated during the watering process, or, for example, immediately after the watering is completed. Preferably, the drainage according to the present invention is initiated within 2 hours, more preferably within 1 hour, even more preferably within 30 minutes, and particularly preferably within 10 minutes, after the completion of the watering process described above. However, if left for more than 3 hours, the floating organic sediment may settle. [Examples]

[0043] The present invention will be specifically described by the following test examples, but the present invention is not limited thereto.

[0044] <Experiment on the buoyancy effect against parasites> Preparation of concentrated solution Organic sediment was sampled from an eel farming facility (Shibushi City, Kagoshima Prefecture), and pure water was added to obtain water containing organic sediment. 1 liter of the obtained water containing organic sediment was filtered through a plankton net with a mesh size of 50 μm (No. 300T, AZONE Co., Ltd.) to obtain the filtration residue. Pure water was added to the obtained filtration residue to make a 100 ml concentrate.

[0045] [Comparative Example 1] 20 ml of the obtained concentrate was added and allowed to stand for 10 minutes. The floating parasites were removed, and the number of parasites in the concentrate was measured using an optical microscope (CX31LBSF, Olympus Corporation) with a plankton measuring plate (MCP-200, Matsunami Glass Industry Co., Ltd.). Pseudodactylogyrus was observed as a parasite.

[0046] [Example 1] Peracetic acid was added to 20 ml of the concentrated solution used in Comparative Example 1 to a concentration of 50 mg / L. After standing for 10 minutes, the floating parasites were removed, and the number of parasites in the concentrated solution was measured using an optical microscope (CX31LBSF, Olympus Corporation) with a plankton measuring plate (MCP-200, Matsunami Glass Industry Co., Ltd.). The same parasites as in Comparative Example 1 were observed.

[0047] [Example 2] The procedure was carried out in the same manner as in Example 1, except that peracetic acid was replaced with hydrogen peroxide. Furthermore, the same parasites as in Comparative Example 1 were observed.

[0048] The measurement results for Comparative Example 1, Example 1, and Example 2 are shown in the table below.

[0049] [Table 1]

[0050] According to Table 1, the result for Example 1 was 3 parasites / 100 μL, and the result for Example 2 was 58 parasites / 100 μL. Comparing these results with Comparative Example 1, it was found that the number of parasites in the concentrated solution was reduced, indicating that the parasites were floating due to the effect of peracetic acid or hydrogen peroxide. In particular, in Example 1, which used peracetic acid, a significantly larger number of parasites floated compared to Comparative Example 1. From this, it is considered that the bubbles produced by the reaction between peroxide and organic sediment are significant in the floating of parasites.

[0051] <Experiment on the levitation of organic matter> 100g of organic sediment was sampled in a 300ml beaker from an eel farming facility (Shibushi City, Kagoshima Prefecture). 100ml of aqueous solutions of peracetic acid, hydrogen peroxide, or sodium hypochlorite, diluted to the concentrations shown in Tables 2-4 below, were added to the 100g of sampled organic sediment. The time from immediately after addition until the organic matter began to float was measured. After measuring the time until the organic matter floated, dissolved oxygen was measured. Furthermore, if the organic matter did not float during a 20-minute standing period, the dissolved oxygen was measured 20 minutes after addition.

[0052] The results using peracetic acid are shown in Table 2.

[0053] [Table 2]

[0054] The results using hydrogen peroxide are shown in Table 3.

[0055] [Table 3]

[0056] The results using sodium hypochlorite are shown in Table 4.

[0057] [Table 4]

[0058] Table 2 shows that peracetic acid, at a concentration of at least 50 mg / L, can generate bubbles through reaction with accumulated organic matter and / or water, causing the organic matter to float to the surface. Table 3 shows that hydrogen peroxide, at a concentration of at least 150 mg / L, can generate bubbles through reaction with organic matter and / or water, causing the organic matter to float to the surface. Table 4 shows that sodium hypochlorite did not cause any organic matter to float to the surface. Comparing Tables 2 and 3, peracetic acid can cause organic matter to float to the surface even at low concentrations such as 50 mg / L. On the other hand, at high concentrations such as 500 mg / L, the time it takes for organic matter to float to the surface is almost the same for peracetic acid and hydrogen peroxide. Regarding dissolved oxygen concentration, hydrogen peroxide was found to have higher values ​​than peracetic acid, except for the value at 50 mg / L. Table 4 suggests that sodium hypochlorite did not cause any organic matter to float to the surface and did not cause any change in dissolved oxygen, which is why no bubbles were generated. This suggests that the bubbles produced by the reaction between peroxides and organic deposits are significant in the uplift of organic matter.

[0059] <Experiment on the buoyancy effect of parasites and parasite eggs in aquaculture ponds> [Comparative Example 5] Organic sediment containing water from eel farms was sampled at multiple locations in an eel farming facility (Shibushi City, Kagoshima Prefecture) to obtain water containing organic sediment. The obtained water containing organic sediment was filtered using a plankton net with a mesh size of 50 μm (No. 300T, AZONE Co., Ltd.) to obtain the filtration residue. This filtration residue was diluted with water from the eel farm to a volume equal to 1 / 3 of the volume of the organic sediment containing the sampled water from the eel farm, to obtain a 3-fold concentrated solution. Two of these solutions were prepared. The number of parasites and parasite eggs (excluding floating parasites and parasite eggs) in these two 3-fold concentrated solutions (number of parasites / 100 μL) was measured using an optical microscope (CX31LBSF, Olympus Corporation) with a plankton measuring plate (MCP-200, Matsunami Glass Industry Co., Ltd.). Pseudodactylogyrus and its eggs were observed as parasites and parasite eggs.

[0060] [Example 5] In an eel farming facility (Shibushi City, Kagoshima Prefecture), a peracetic acid solution was added from the edge of the facility so that the concentration of peracetic acid in the water of the farming pond reached 250 mg / L. Without stirring, after 1 hour, samples were taken of the farming pond water and organic sediment at multiple locations near the sampling site of Comparative Example 5 where organic sediment had accumulated, and water containing organic sediment was obtained. The procedure was the same as in Comparative Example 5. As for parasitic eggs, Pseudodactylogyrus eggs were observed.

[0061] [Example 5-1] The procedure was the same as in Example 5, except that the sampling was changed from 1 hour later to 24 hours later.

[0062] The results for Comparative Example 5, Example 5, and Example 5-1 are shown in Table 5.

[0063] [Table 5]

[0064] According to Table 5, in Example 5, no parasite eggs floated to the surface on the second attempt, and although one remained in the 3x concentrated solution, all the others were floating. In Example 5-1, all parasites and parasite eggs floated to the surface and none remained. From these results, it is considered that even when using organic sediment and water from actual aquaculture ponds, parasites and parasite eggs can be made to float by allowing peroxide to act for 1 hour or more, preferably 24 hours or more. Furthermore, in Examples 5 and 5-1, the number of parasites and parasite eggs decreased or became zero, suggesting that the flotation effect of peroxide can be sufficiently generated without stirring the water or organic sediment.

[0065] Furthermore, using the data in Table 5, the number of parasites and parasite eggs (per 1 mL) contained in actual aquaculture facilities was predicted using the following formula (1). Note that formula (1) is derived by calculating the average of the parasites or parasite eggs from the first and second trials, increasing the denominator representing volume from 100 μL to 1 mL (10 times), and changing from 3-fold concentration to no concentration.

number

[0066] Applying the formula in Equation 1 above to the data in Table 5, the calculated results are shown in Table 6.

[0067] [Table 6]

[0068] According to Table 6, in Example 5, although some parasite eggs remained in the organic sediment, all parasites floated to the surface, and more than 80% of the parasite eggs also floated to the surface. In Example 5-1, all parasites and parasite eggs floated to the surface and were not left in the organic sediment. From this, it can be concluded that even when considering an actual aquaculture facility, parasites and parasite eggs can be made to float by allowing peroxide to act for 1 hour or more, preferably 24 hours or more.

Claims

1. The process includes the steps of: adding peracetic acid or an aqueous solution of the peracetic acid to an aquaculture facility containing organic sediment and water, and in which there are no aquaculture targets; reacting the organic sediment and / or the water with the peracetic acid to generate bubbles; and using the bubbles to cause at least a portion of the organic sediment and / or the precipitate contained in the organic sediment to float to the surface. Aquaculture facility management methods.

2. The aquaculture facility management method according to claim 1, further comprising the step of draining the water from the aquaculture facility after floating at least a portion of the organic sediment and / or the sediment contained in the organic sediment to the surface, and then removing the floating organic sediment and / or the sediment contained in the organic sediment.

3. The aquaculture facility management method according to claim 1, further comprising the steps of: adding water to the aquaculture facility after floating at least a portion of the organic sediment and / or the sediment contained in the organic sediment to the surface; and draining the water from the aquaculture facility during or after adding water to remove the floating organic sediment and / or the sediment contained in the organic sediment.

4. The method for managing an aquaculture facility according to claim 1, further comprising the step of stirring the organic sediment and / or the water during or after the addition of the peracetic acid or an aqueous solution of the peracetic acid.

5. The aquaculture facility management method according to claim 1, wherein the concentration of peracetic acid in the water of the aquaculture facility after it has been added to the aquaculture facility is 25 mg / L to 1000 mg / L.

6. The aquaculture facility management method according to claim 1, wherein the precipitate contained in the organic sediment includes parasites, parasite eggs and / or parasite cysts.

7. The method for managing an aquaculture facility according to claim 6, wherein the parasite is Pseudodactylogyrus and / or Ichthyophthirius multifiliis.

8. The aquaculture facility management method according to claim 1, wherein the sediment contained in the organic sediment contains microplastics.

9. The aquaculture facility management method according to claim 1, wherein the aquaculture facility is an eel or salmon / trout aquaculture facility.

10. The aquaculture facility management method according to claim 1, wherein the height from the bottom of the aquaculture facility to the top of the water is at least twice the height from the bottom of the aquaculture facility to the top of the organic sediment.

11. The aquaculture facility management method according to claim 1, wherein the height from the bottom surface of the aquaculture facility to the top surface of the water is at least 5 cm from the top surface of the organic sediment.

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