Shellfish and fish rearing and growth system and method

Abstract

To provide a shellfish and fish rearing and growth system and method.SOLUTION: A shellfish and fish rearing and growth system comprises: a rearing and cultivating facility 11 for rearing and growing shellfish and fish; a physical filtration device 13 such as a filter that removes sludge in drain water 12 from the rearing and cultivating facility (aquaculture tank) 11; an aerobic biological treatment device 14 that reduces biochemical oxygen demand (BOD) in the treated water after removing the sludge and converts part thereof to nitrites; an anammox treatment device 15 that denitrifies ammoniacal nitrogen in the treated water 13A from the biological treatment device 14 through the anammox processing; an oxygen supply device 16 that supplies oxygen (O2) to the treated water 14A after denitrification; and a sterilization device 17 that sterilizes the treated water after oxygen supply.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fish and shellfish rearing and growing system and method. [Background technology]

[0002] Traditional marine aquaculture in bays and other locations is subject to changes in conditions such as water depth, weather, and tides, and stable aquaculture is not possible due to deterioration of the aquaculture environment and weather conditions. In recent years, land-based aquaculture, which is less susceptible to external factors such as restrictions on aquaculture locations and weather conditions, has been attracting attention. In closed-circulation land-based aquaculture, a filtration system is used to purify the aquaculture water (breeding water) and recycle it (see Patent Document 1). For example, the treatment procedure for conventional aquaculture facilities involves physical filtration to remove debris and other sediments from the breeding tank, followed by biological treatment (aerobic circulating nitrification and denitrification), followed by pH adjustment, appropriate control of the dissolved oxygen concentration and water temperature, and then a circulation system in which the water is returned to the breeding tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-186994 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, proposals such as that in Patent Document 1 have the problem that the denitrification process, which is an aerobic, cyclical nitrification-denitrification method used to treat the highly toxic ammonia contained in the feces of fish, requires a long retention time and a large amount of air (oxygen). Therefore, there is a strong need for a fish and shellfish rearing and growing system that can reduce running costs such as the electricity costs associated with aeration of the aquaculture environment, such as by eliminating the retention time during denitrification and the need for large amounts of air (oxygen), and that also reduces the amount of work required compared to other aquaculture methods.

[0005] In view of the above problems, the present invention provides a fish and shellfish rearing and growing system and method that does not require much time for denitrification treatment and can stabilize the aquaculture environment. [Means for solving the problem]

[0006] One embodiment of the fish and shellfish rearing and growing system of the present invention is characterized by comprising rearing and farming facilities for rearing and growing fish and shellfish, a physical filtration device such as a filter for removing screen residue from wastewater from the rearing and farming facilities, a biological treatment device for reducing the BOD in the treated water after the screen residue is removed and for partially nitrifying it, an anammox treatment device for denitrifying ammonia nitrogen in the treated water from the biological treatment device by anammox treatment, an oxygen supplying device for supplying oxygen to the treated water after denitrification, and a sterilization device for sterilizing the treated water after oxygen supply.

[0007] One embodiment of the fish and shellfish rearing and growing method of the present invention is characterized by comprising a rearing and culturing process for rearing and growing fish and shellfish, a physical filtration process using a filter or the like for removing screen residue from wastewater from rearing and culturing tanks, a biological treatment process for reducing the BOD in the treated water after screen residue removal and for partially nitrifying it, an anammox treatment process for denitrifying ammonia nitrogen in the treated water from the biological treatment process by anammox treatment, an oxygen supply process for supplying oxygen to the treated water after denitrification, and a sterilization process for sterilizing the treated water after oxygen supply. Effect of the Invention

[0008] The present invention can contribute to the miniaturization of the system. The anammoc process can remove nitrogen with a retention time of, for example, about 1 / 3 to 1 / 4 of that of the circulating nitrification denitrification process, and can significantly shorten the processing time. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a fish and shellfish rearing and growing system according to a first embodiment of the present invention. [Diagram 2]FIG. 1 is a schematic diagram of a fish and shellfish rearing and growing system according to a second embodiment of the present invention. [Diagram 3] FIG. 11 is a schematic diagram of a fish and shellfish rearing and growing system according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout.

[0011] [First embodiment] Fig. 1 is a schematic diagram of a fish and shellfish rearing and growing system according to a first embodiment of the present invention. As shown in Fig. 1, the fish and shellfish rearing and growing system 10A of this embodiment includes a closed circulation type rearing and growing facility (hereinafter also simply referred to as "farming tank") 11 installed indoors for rearing and growing fish and shellfish, a physical filtration device 13 such as a filter for removing screen residue from wastewater (including overflow water, etc.) 12 from the farming tank 11, an aerobic biological treatment device (hereinafter also referred to as "biological treatment device") 14 for reducing BOD (biological oxygen demand) in treated water 13A after screen residue removal and partially nitrifying the treated water, an anammox treatment device 15 for denitrifying ammonia nitrogen in the treated water 14A from the biological treatment device 14 by anammox treatment, an oxygen supplying device 16 for supplying oxygen (O2) to the treated water 15A after denitrification, and a sterilization device 17 for sterilizing the treated water 16A after oxygen supply.

[0012] Here, BOD (biological oxygen demand) refers to the biochemical oxygen demand required for organic matter to be biologically decomposed and stabilized in the presence of dissolved oxygen, and is one of the indicators of water pollution. Usually, the standard is the amount of oxygen consumed over a five-day period at 20°C.

[0013] A fish and shellfish rearing and growing system 10A according to the present invention is for rearing and growing fish and shellfish in a closed circulation type rearing and farming facility (raising facility and farming facility) 11. Here, the breeding facilities refer to facilities such as aquariums where fish and shellfish are exhibited and bred. Additionally, aquaculture facilities refer to facilities for cultivating and raising fish and shellfish in aquaculture tanks. In the present invention, aquariums and closed aquaculture facilities are collectively referred to as "breeding and aquaculture facilities (equipment)".

[0014] Closed circulation aquaculture indoors has the advantage that it is less susceptible to the influence of the external environment (external factors) and the breeding environment is easier to control. In addition, because wastewater is treated within the aquaculture tank through complete circulation, it has the advantage of being able to control emissions and is less likely to pollute the external environment. Moreover, because artificial seawater is used, there is little risk of contamination by parasites or diseases, and there are also advantages in that the aquaculture site can be set up regardless of location.

[0015] Here, the main targets of land-based aquaculture include fish and shellfish such as rainbow trout, trout salmon, cherry salmon, satsuki salmon, flounder, tiger puffer, sturgeon, filefish, grouper, horse mackerel, mackerel, pacific saury, shrimp, white shrimp, abalone, eel, and sea urchin, and seaweed such as wakame seaweed and kelp. Another example is seahorse, which is a raw material for herbal medicine, but the present invention is not limited to these.

[0016] An aquarium is a place where fish and shellfish are raised and exhibited, and wastewater from such an aquarium may be treated.

[0017] The salinity of the artificial seawater depends on the fish and shellfish being raised, but can be from about 3.5%, which is the same as that of general seawater, to a low salinity (for example, 1.5% or more, preferably about 2 to 3%). In the present invention, the salinity is preferably 1.5% or more and 3.5% or less. It is preferable to use seawater with a low salinity for rearing, since it is expected that the living organism will become enlarged.

[0018] The tanks of the breeding / cultivation facility 11 may be appropriately selected depending on the growth process of the fish from juveniles. This is because the conditions for growing juvenile fish and fully grown fish are different, and therefore the tanks are different. In particular, for juvenile fish (which do not molt), the food they eat changes as they grow. Also, for farmed species such as crabs, which do molt, the type of food they eat is different.

[0019] The physical filtration device 13 treats the wastewater (including overflow water) 12 from the breeding and aquaculture equipment 11 to remove suspended solids (SS) and organic solids, and examples of such treatment devices include known treatment devices such as a filter removal device or a foam separation device. Here, the term "screen residue" refers to solid garbage (including floating matter) that is mixed in the water tanks of the breeding and aquaculture equipment 11.

[0020] The aerobic biological treatment device 14 is an oxidation treatment device for reducing the BOD (biological oxygen demand) in the treated water after screen residue removal, and also oxidizes a portion of the ammoniacal nitrogen (NH4-N) (also called ammonia nitrogen) to NO2-N (nitrite nitrogen), oxidizing a portion of the ammoniacal nitrogen by air aeration.

[0021] The anammox treatment device 15 denitrifies the nitrogen components contained in the treated water 14A through the anaerobic ammonium oxidation (Anammox) reaction. The anammox reaction is a reaction in which anammox bacteria convert NH4-N (ammonia nitrogen) and NO2-N (nitrite nitrogen) into N2 (nitrogen gas) and NO3-N (nitrate nitrogen) under anaerobic conditions, and is shown in the following reaction formula (1). 1.0NH4 + +1.32NO2 - +0.066HCO3 - +0.13H + →1.02N2+0.26NO3 - +0.066CH2O 0.5 N 0.15 +2.03H2O …(1)

[0022] Since the anammox process is a process carried out under anaerobic conditions, it is preferable that the amount of dissolved oxygen (DO) is about 0.5 mg / L or less. Here, dissolved oxygen (DO) refers to the oxygen (O2) that is dissolved in water, and in nature, it dissolves in water in proportion to the partial pressure of oxygen (O2) in the atmosphere.

[0023] The anammox treatment device 15 according to the present invention also includes a single-layer treatment device in which ammonia oxidizing bacteria (AOB) and anammox bacteria are attached.

[0024] Since the anammox treatment device 15 operates under anaerobic conditions, it is preferable to close the opening of the device with a lid or the like.

[0025] Since the anammox treatment device 15 operates under anaerobic conditions, it is necessary to lower the oxygen concentration from the culture tank 11 to the anammox treatment tank 15.

[0026] Here, an outline of the steps of the fish and shellfish rearing and growing treatment method in which wastewater 12 from the aquaculture tank 11 is treated and returned to the aquaculture tank 11 as treated water 17A will be described. Step 1) Fish and other organisms are cultivated in aquaculture tanks 11. Step 2) When culturing fish, residue such as garbage in wastewater (or overflow water) 12 from the culture tank 11 is treated with a physical filtration device 13, for example, a filter. Step 3) The treated water 13A after the filter treatment is passed through an aerobic biological treatment device 14, where the BOD in the treated water 13A is reduced and at the same time, a part of the ammoniacal nitrogen is converted to nitrite. Step 4) Ammoniacal nitrogen in the treated water 14A from the aerobic biological treatment device 14 is denitrified by anammox treatment in the anammox treatment device 15. Step 5) The treated water 15A after denitrification is supplied with oxygen (O2) in an oxygen supplying device 16 so that the concentration becomes a predetermined value. Step 6) The treated water 16A after the oxygen supply is sterilized in the sterilization device 17. Step 7) The treated water 17 after disinfection is returned to the aquaculture tank 11.

[0027] In these treatment steps, oxygen is no longer added to the treated water 14A that has been treated in the aerobic biological treatment device 14, and the oxygen concentration therein naturally decreases. In this embodiment, the oxygen concentration in the treatment liquid 14A before being introduced into the anammox treatment device 15 is set to 0.05 mg / L or less (preferably 1.0 mg / L or less).

[0028] Therefore, as a countermeasure in the case where the oxygen concentration in the treated water 14A is not equal to or lower than the specified value, a buffer tank (storage tank) such as a tank may be installed on the line L3 upstream of the anammox treatment device 15 to create a predetermined anaerobic atmosphere (oxygen concentration: 0.05 mg / L or less (1.0 mg / L or less). This is because by providing this buffer tank, the oxygen concentration gradually decreases due to the growth of microorganisms in the treated water 14A inside the buffer tank.

[0029] The oxygen supplying device 16 supplies oxygen to the treatment water 15A under anaerobic conditions to control the dissolved oxygen concentration, and adjusts the amount of dissolved oxygen (DO) appropriately depending on the species of fish being raised and bred. The method of supplying oxygen is not particularly limited, and any known oxygen supplying device such as a bubbling device using an air diffuser or a Venturi tube can be used. In addition, the supply of oxygen through the Venturi tube creates fine bubbles, enabling oxygen to be efficiently dissolved in the treatment water 15A.

[0030] The oxygen supply may be in the form of nanobubbles from an oxygen nanobubble generator. When the treated water 17A is returned to the aquaculture tank 11, it is preferable that the dissolved oxygen (DO) value of the returned treated water 17A is set to 3 mg / L or more.

[0031] The sterilization device 17 is a device that irradiates ultraviolet (UV) rays having a wavelength of, for example, 253.7 nm to kill, for example, algae, bacteria, mold, viruses, etc. floating in the treatment water 16A, thereby improving the breeding and growth environment for the fish species being bred and raised. Further, deep ultraviolet light (UV-C / Deep-UV; light with a short wavelength of 100 to 280 nm) may be used to sterilize water.

[0032] In addition to UV irradiation, a seawater electrolysis sterilization device can also be used. Seawater electrolysis sterilization devices can exert a strong cleaning power by generating minute amounts of hypochlorous acid, which has high sterilizing power, and can also improve hygiene management significantly without adding any chemicals.

[0033] If necessary, a pH adjusting device for adjusting the pH of the treated water, a water temperature adjusting device for adjusting the water temperature, etc. may be appropriately installed.

[0034] As described above, this embodiment can contribute to the miniaturization of fish and shellfish breeding and growth systems. Anammoc treatment can remove nitrogen with a retention time of, for example, about 1 / 3 to 1 / 4 of that of the circulating nitrification and denitrification method, and can significantly reduce the treatment time. At the same time, the running cost can be significantly reduced by reducing the power required for aeration.

[0035] [Second embodiment] Fig. 2 is a schematic diagram of a fish and shellfish rearing and growing system according to a second embodiment of the present invention, in which the same components as those in the fish and shellfish rearing and growing system 10A according to the first embodiment shown in Fig. 1 are designated by the same reference numerals and will not be described.

[0036] The fish and shellfish breeding and growing system 10B of the second embodiment shown in FIG. 2 includes a branch line L that branches off treated water 14A from a biological treatment device 14 to be introduced into an anammox treatment device 15. 3-1 ,L 3-2 The branch portion 21 is provided with: And one of the branched lines, L 3-1The treated water 14A1 introduced by the anammox treatment device 15 is denitrified, and the other branched line L 3-2 The treated water 14A2 introduced from the oxygen supply device 16 is bypassed and joined at a joining point 22 just before the oxygen supply device 16. This reduces the processing capacity of the anammox processing device 15, thereby making it possible to reduce the volume of the anammox processing device 15 and to make the processing system more compact.

[0037] Regarding the nitrogen concentration of ammonia, the "appropriate amount of ammonia concentration varies" depending on the fish species. Therefore, it is preferable to determine in advance the correlation between the fish species and the ammonia concentration and determine whether to put the entire amount of the treated water into the anammox treatment tank or a certain percentage of the treated water into the anammox treatment tank. By adopting this bypass process, the load on the anammox treatment device 15 can be reduced, which contributes to making the equipment more compact.

[0038] In addition, when operating land-based aquaculture, it is preferable to determine in advance when installing the land-based aquaculture system whether to bypass a portion of the treated water and treat the remaining amount, or to treat the entire amount, depending on the concentration of ammonia nitrogen. When the entire amount is to be treated, the system 10A of the first embodiment is used.

[0039] Here, when measuring ammonia nitrogen, for example, when multiple aquaculture tanks are installed, it is sufficient to measure once a day using a portable measuring device.

[0040] The amount of ammoniacal nitrogen can be measured, for example, by spectrophotometry, potentiometry (membrane electrode method), ion electrode method, coulometric titration method, ion chromatography method, and the like. In land-based aquaculture equipment, it is preferable to use a measuring device that uses an ion electrode method, which does not require reagents or sampling and is the optimal method for continuous measurement.

[0041] [Third embodiment] Fig. 3 is a schematic diagram of a fish and shellfish rearing and growing system according to a third embodiment of the present invention. As shown in Fig. 3, a fish and shellfish rearing and growing system 10C of this embodiment is provided with an anaerobic MBR (Membrane Bioreactor) device, which is an anaerobic biological treatment device, instead of an aerobic biological treatment device 14. The organic matter in the wastewater is decomposed by anaerobic bacteria in the anaerobic MBR device 31 to generate methane (CH4) gas and carbon dioxide (CO2), which are separated as biogas and sent to the outside, and the treated water that has been purified by MBR processing passes through the membrane. The membrane permeate water that permeates the membrane passes through the anammox treatment device 15 installed downstream as treated water 31A, where some of the ammoniacal nitrogen is oxidized to nitrite nitrogen, which is then reacted with unreacted ammoniacal nitrogen by anammox bacteria for denitrification. The obtained biogas may be utilized effectively.

[0042] By installing the anaerobic MBR apparatus 31, treatment can be performed under anaerobic conditions together with the anaerobic anammox treatment apparatus 15 installed downstream.

[0043] The anaerobic MBR device 31 uses a separation membrane installed inside to maintain high concentrations of sludge material and microorganisms necessary for decomposition, and to improve the quality of treated water. By subjecting high-concentration sludge material to anaerobic fermentation, organic matter is converted into methane gas, and the amount of sludge generated can be reduced.

[0044] In addition, since a separation membrane with pores smaller than the microorganisms is used, the outflow of SS components can be reduced. As a result, according to the present embodiment, it is possible to obtain clear treated water 31A using a compact system as compared with the conventional method. In addition, it is possible to effectively utilize the generated methane gas (for example, as an energy source for heating or power generation).

[0045] In this way, the fish and shellfish rearing and growing system of the present invention can provide equipment that does not require retention time or large amounts of air (oxygen) for denitrification treatment, reduces running costs such as electricity costs associated with aeration of the aquaculture environment, and also reduces the amount of work compared to other aquaculture methods. [Industrial Applicability]

[0046] The present invention can be used in general technology related to fish and shellfish rearing and breeding systems and methods. [Explanation of symbols]

[0047] 10A~10C Fish and shellfish breeding and growth system 11 Breeding and farming facilities 12 Drainage (overflow water) 13 Physical filtration equipment 14 Aerobic biological treatment equipment (biological treatment equipment) 15 Anammox Processing Equipment 16 Oxygen supply equipment 17 Sterilizer 14A~17A, 31A Treated water 31 Anaerobic MBR Equipment

Claims

1. Aquaculture facilities for raising and cultivating fish and shellfish; A physical filtration device for removing sediment from wastewater from the breeding and aquaculture facilities; A biological treatment device that reduces the BOD in the treated water after removing the screen residue and partially converts it to nitrite; An anammox treatment device that denitrifies ammonia nitrogen in the treated water from the biological treatment device by anammox treatment; an oxygen supplying device for supplying oxygen to the treated water after denitrification; A sterilization device for sterilizing the treated water after oxygen supply; A fish and shellfish rearing and growing system comprising:

2. A branching section is provided with a branching line that branches off treated water from the biological treatment device to be introduced into the anammox treatment device, One of the branched waters is treated in the anammox treatment device, 2. The fish and shellfish rearing and growing system according to claim 1, wherein other branched water is bypassed and merged before the oxygen supply device.

3. A fish and shellfish rearing and growing system as described in claim 1 or 2, characterized in that the salinity of the rearing and farming facility is 1.5% or more and 3.5% or less.

4. A fish and shellfish rearing and growing system according to claim 1 or 2, characterized in that the biological treatment device is either an aerobic biological treatment device or an anaerobic biological treatment device.

5. A breeding and farming process for raising and growing fish and shellfish; A physical filtration process to remove residue from wastewater from breeding and aquaculture tanks; A biological treatment process for reducing the BOD in the treated water after removing the screen residue and partially converting it to nitrite; An anammox treatment process in which ammonia nitrogen in the treated water from the biological treatment process is denitrified by anammox treatment; an oxygen supply step for supplying oxygen to the treated water after denitrification; a sterilization step of sterilizing the treated water after oxygen supply; A method for raising and cultivating fish and shellfish, comprising the steps of:

6. Branching the treated water from the biological treatment process to be introduced into the anammox treatment process; One of the branched water is treated in the anammox treatment process, 6. The method for raising and growing fish and shellfish according to claim 5, wherein the other branched water is bypassed and joined together before the oxygen supply step.

7. A method for rearing and growing fish and shellfish according to claim 5 or 6, characterized in that the salinity of the rearing and farming facility is 1.5% or more and 3.5% or less.

8. A method for raising and cultivating fish and shellfish as described in 5 or 6, characterized in that the biological treatment process is either an aerobic biological treatment process or an anaerobic biological treatment process.

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