A sunlight factory recirculating aquaculture system and method

Abstract

The present invention provides a sunlight factory recirculating aquaculture system and method, belonging to the technical field of aquaculture. The sunlight factory recirculating aquaculture system includes a fish pond and a fiber rotary disk filtration system; the fiber rotary disk filtration system can remove large-particle-size particulate matters in the culture water and regularly harvest microalgae, and the treated water quality meets the fishery culture standard, and 97% of the culture water can be directly recycled. In the present invention, during the in-situ cultivation of microalgae and fish, the microalgae can convert nutrients such as CO2 exhaled by the fish and nitrogen and phosphorus in the culture water body into substances of the microalgae cells themselves, such as proteins, polysaccharides, vitamins, and lipids, and release oxygen, rapidly improving the culture water quality; the in-situ cultivation of microalgae and fish gives play to the advantage of the high photosynthetic efficiency of the microalgae, and the rapidly growing microalgae provides a suitable growth environment for the fish. The sunlight factory recirculating aquaculture system and method of the present invention can achieve high-density, high-stability, and low-energy-consumption recirculating aquaculture.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and in particular relates to a solar-powered industrialized circulating water fish farming system and method. Background Art

[0002] Aquaculture is an important part of my country's food security system, providing the public with a large amount of high-quality animal protein. Recirculating aquaculture has become an inevitable trend in the development of aquaculture today due to its advantages of water conservation, high breeding density, controllable system, and low impact from the external environment. The current recirculating aquaculture system usually includes treatment units such as sedimentation, filtration, biological filter, oxygenation, temperature control, and sterilization and disinfection. Among them, the biological filter as the core unit only uses nitrification reaction to convert harmful nitrogen-containing pollutants into less toxic nitrate nitrogen, and cannot completely remove it from the aquaculture water. In order to further improve the self-purification capacity, in recent years, large algae, aquatic plants and aquaculture species have been cultured in situ, and their photosynthesis has been used to remove pollutants such as N and P in the aquaculture water, thereby effectively improving the water quality and achieving the purpose of reducing CO2 emissions to a certain extent. Despite this, there are also new problems. For example, large algae and aquatic plants require high light intensity to efficiently convert N and P, while fish prefer a relatively dark environment; for example, large algae and aquatic plants need to be harvested regularly, making it difficult to ensure the stability of the N and P removal capacity of the recirculating aquaculture system.

[0003] Microalgae are a type of single-cell algae that is tiny in size, simple in structure, and grows rapidly. They have the advantages of high photosynthetic efficiency, strong environmental adaptability, short doubling time, and easy integration with other engineering technologies. Microalgae can convert NH4 + -N, NH3-N, NO2 - -N、NO3 - -N, PO4 3- -P and other inorganic forms of nitrogen and phosphorus nutrients into algae cell's own substances such as protein, polysaccharide, fat, vitamins and nucleic acid. The combination of microalgae cultivation and aquaculture wastewater treatment can simultaneously achieve aquaculture wastewater purification, N and P nutrient recovery, and the production of edible microalgae for fish. For this reason, the solar factory-scale circulating water system for in-situ aquaculture of microalgae and fish has great potential.

[0004] As is well known, the particulate matter in circulating water is complex in composition, including fish feces, residual bait, etc., with a very wide range of size variations, from centimeters to nanometers. If many particulate matters are not removed in time, they will become smaller and even be dissolved. The current treatment method is to first remove large-sized particulate matters by sedimentation and screen filtration, and then remove tiny-sized particulate matters by foam separation. The introduction of microalgae makes the particulate matter composition in the sunlight factory-scale circulating water fish farming system more complex. Large-sized particulate matters are also preferentially removed, and microalgae are only removed from the system when it comes to harvesting. Therefore, how to efficiently remove large-sized particulate matters and regularly harvest microalgae is the key to determining the success or failure of the sunlight factory-scale circulating water fish farming system. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a sunlight factory-scale circulating water fish farming system and method. The sunlight factory-scale circulating water fish farming system of the present invention is a fish farming system for in-situ cultivation of fish and microalgae, which can achieve high-density, high-stability, and low-energy-consumption circulating water fish farming.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a sunlight factory-scale circulating water fish farming system, including a fish pond and a fiber rotary disk filtration system;

[0008] The fish pond includes: a fish pond body, a water inlet, and a water outlet;

[0009] The fiber rotary disk filtration system includes a first fiber rotary disk filtration system and a second fiber rotary disk filtration system;

[0010] The first fiber rotary disk system is located in the first filtration tank; the second fiber rotary disk filtration system is located in the second filtration tank;

[0011] The first fiber rotary disk filtration system includes a first fiber rotary disk filter;

[0012] The second fiber rotary disk filtration system includes a second fiber rotary disk filter;

[0013] The filtration aperture of the filter cloth in the first fiber rotary disk filter is 15 - 30 μm;

[0014] The filtration aperture of the filter cloth in the second fiber rotary disk filter is 1 - 5 μm;

[0015] The first fiber rotary disk filtration system and the second fiber rotary disk filtration system respectively include a backwashing system and a supporting electrical control system;

[0016] The water outlet of the fish pond is communicated with the first filtration tank and the second filtration tank respectively through pipelines;

[0017] The filtered water outlet of the fiber rotary disk filtration system is communicated with the water inlet of the fish pond through a pipeline.

[0018] Preferably, the filtration fluxes of the first fiber rotary disk filtration system and the second fiber rotary disk filtration system for the same aquaculture sewage are equal.

[0019] Preferably, a filtered water collection tank is arranged between the first filtration tank and the second filtration tank; a filtered water outlet is arranged at the bottom of the filtered water collection tank; sewage outlets are respectively arranged on the first filtration tank and the second filtration tank; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system share a filtered water collection tank and a filtered water outlet.

[0020] Preferably, the fiber rotary disk filtration system further includes a sludge discharging system; the sludge discharging system includes sludge discharging pipes respectively arranged at the bottoms of the first filtration tank and the second filtration tank, and the sludge discharging pipes are communicated with a reverse suction pump through pipelines.

[0021] Preferably, electric valves are respectively arranged on the sludge discharging pipes in the first filtration tank and the second filtration tank; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system share a reverse suction pump.

[0022] The present invention also provides a method for sunlight factory recirculating aquaculture of fish using the sunlight factory recirculating aquaculture system according to the above scheme, including the following steps:

[0023] 1) Inject water into the fish pond body and add pre-cultured highly active microalgae until the algae density in the aquaculture water body is 50-1000 mg / L;

[0024] 2) Release fry and feed the fish pond every 3-5 h;

[0025] 3) During the aquaculture process, when the microalgae are at the end of the stable growth phase and are about to enter the decline phase, close the first fiber rotary disk filter, open the second fiber rotary disk filter, so that the microalgae cannot return to the fish pond, and the intercepted microalgae are discharged through the backwashing system, and add a certain volume of pre-cultured highly active microalgae to make the algae density in the aquaculture water body 50-1000 mg / L, and harvest the fish after 150-200 d.

[0026] Preferably, the aquaculture density in step 1) is 25-35 kg / m 3 .

[0027] Preferably, when the aquaculture density in the water body is greater than or equal to 30 kg / m 3 , and less than 60 kg / m 3 , the water inflow and the water outflow are respectively set to 35-45 m 3 / h; when the aquaculture density in the water body is greater than or equal to 60 kg / m 3, and less than 100 kg / m 3 When it is, the water inflow and water outflow are respectively set to 55 - 65 m 3 / h; when the aquaculture density in the water body is greater than or equal to 100 kg / m 3 , and less than 200 kg / m 3 When it is, the water inflow and water outflow are set to 70 - 90 m 3 / h.

[0028] Preferably, during the aquaculture process, the dissolved oxygen content in the aquaculture water body is 5 - 12 mg / L.

[0029] Preferably, the microalgae can pass through the filter cloth in the first fiber rotary disk filter and cannot pass through the filter cloth in the second fiber rotary disk filter; the microalgae include one or more of Chlorella vulgaris, Nannochloropsis oculata, Dunaliella salina, and Chlamydomonas reinhardtii.

[0030] The beneficial effects of the present invention: The present invention provides a sunlight factory - type circulating water fish - farming system, including a fish - farming pond and a fiber rotary disk filtration system; the fiber rotary disk filtration system includes a first fiber rotary disk filtration system and a second fiber rotary disk filtration system; the first fiber rotary disk system is located in the first filtration pond; the second fiber rotary disk filtration system is located in the second filtration pond; the first fiber rotary disk filtration system includes a first fiber rotary disk filter; the second fiber rotary disk filtration system includes a second fiber rotary disk filter; the filtration pore diameter of the filter cloth in the first fiber rotary disk filter is 15 - 30 μm; the filtration pore diameter of the filter cloth in the second fiber rotary disk filter is 1 - 5 μm.

[0031] During the normal microalgae aquaculture period, the first fiber rotary disk filter with a filtration pore diameter of 15 - 30 μm is turned on, and the microalgae can pass through the first fiber rotary disk filter and return to the fish pond for continuous aquaculture; large - particle substances such as fish feces and residual baits either directly sink to the bottom of the filtration pond or are intercepted by the filter cloth of the first fiber rotary disk filter, and finally are discharged through the sludge discharge system or the back - flushing system for further deep purification treatment. When it is necessary to harvest the microalgae in the aquaculture water body, the second fiber rotary disk filter with a filtration pore diameter of 1 - 5 μm is turned on for interception, so that the microalgae cannot return to the fish pond. In the present invention, the fiber rotary disk filtration system not only can perform filtration but also has a sedimentation function. The direct sinking of large - particle substances in the aquaculture sewage to the bottom effectively avoids the water quality deterioration caused by fragmentation, significantly reduces the sludge amount on the filter cloth, and reduces the back - flushing water volume.

[0032] The method for sunlight factory recirculating aquaculture provided by the present invention enables the aquaculture sewage to selectively pass through the first fiber rotary disk filter or the second fiber rotary disk filter. Among them, the pore size of the filter cloth of the first fiber rotary disk filter allows microalgae to pass through while large particle-size particles cannot pass through, and the pore size of the filter cloth of the second fiber rotary disk filter does not allow microalgae to pass through. Thus, large particle-size particles larger than the pore size of the filter cloth of the first fiber rotary disk filter, such as fish feces and residual bait, can be quickly removed from the fish pond, while the microalgae can return to the fish pond for in-situ culture with the fish. The microalgae convert nutrients such as CO2 exhaled by the fish, nitrogen, and phosphorus dissolved in water into substances of the microalgae themselves, such as proteins, polysaccharides, lipids, and vitamins, through photosynthesis, and release oxygen, rapidly improving the aquaculture water quality and significantly reducing the demand for artificial aeration. In the present invention, the aquaculture sewage is regarded as a valuable resource. The fish and microalgae are cultured in-situ in the fish pond, not only realizing the purification of the aquaculture sewage and the recovery of nutrients, but also producing microalgae biomass that the fish can directly consume or that is beneficial to the growth of the fish. In the present invention, the microalgae and fish are cultured in-situ, giving full play to the advantage of the high photosynthetic efficiency of the microalgae, and the rapidly growing microalgae provide a suitable growth environment for the fish.

[0033] In the present invention, the fiber rotary disk filtration system quickly removes the microalgae at the end of the stable growth period from the fish pond, avoiding water quality deterioration caused by microalgae problems. The filtration accuracy of the fiber rotary disk filtration system can reach 1 μm, which can intercept more than 99% of the particles in the aquaculture sewage, and the total solid content of the filtered water is less than 2 mg / L.

[0034] In the present invention, the microalgae with absolute advantages can inhibit the rapid proliferation of harmful bacteria in the aquaculture water body, significantly reducing the use of fish drugs during aquaculture and realizing truly green aquaculture; in addition, the active functional groups on the surface of the microalgae can also promote the aggregation of extremely small particles, eliminating the need for equipment to remove small particles. In the present invention, the reuse rate of the aquaculture sewage can reach 97%, and the recirculating aquaculture of fish can be realized with low energy consumption and high stability. Description of the Drawings

[0035] Figure 1 It is a top view of the fish pond, where 1 is the fish pond body, 2 is the water inlet, 3 is the water outlet, 4 is the water outlet valve, 5 is the water pump, 21 is the inlet of the first filtration pond, 22 is the inlet of the second filtration pond, 23 is the first filtration pond, 24 is the second filtration pond, 25 is the first fiber rotary disk filtration system, 26 is the second fiber rotary disk filtration system, 27 is the filtered water collection tank, 28 is the filtered water outlet, and 29 is the supporting electrical control system;

[0036] Figure 2Schematic diagram of the sludge discharge system for the fiber rotary disk filtration system. Among them, 21 is the inlet of the first filtration tank, 22 is the inlet of the second filtration tank, 23 is the first filtration tank, 24 is the second filtration tank, 28 is the filtered water outlet, 30 is the sewage suction port, 31 is the back suction pump, and 32 is the sewage suction pipe. Detailed implementation mode

[0037] The present invention provides a sunlight factory recirculating aquaculture system, which includes an aquaculture pond and a fiber rotary disk filtration system; the aquaculture pond includes: a pond body, an inlet and an outlet; the fiber rotary disk filtration system includes a first fiber rotary disk filtration system and a second fiber rotary disk filtration system; the first fiber rotary disk system is located in the first filtration tank; the second fiber rotary disk filtration system is located in the second filtration tank; the first fiber rotary disk filtration system includes a first fiber rotary disk filter; the second fiber rotary disk filtration system includes a second fiber rotary disk filter; the filtration aperture of the filter cloth in the first fiber rotary disk filter is 15-30 μm; the filtration aperture of the filter cloth in the second fiber rotary disk filter is 1-5 μm; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system respectively include a backwashing system and a supporting electrical control system; the outlet of the aquaculture pond is communicated with the first filtration tank and the second filtration tank respectively through pipelines; the filtered water outlet of the fiber rotary disk filtration system is communicated with the inlet of the aquaculture pond through a pipeline.

[0038] In the present invention, the sunlight factory recirculating aquaculture system includes a fiber rotary disk filtration system; the fiber rotary disk filtration system includes a first fiber rotary disk filtration system and a second fiber rotary disk filtration system; the first fiber rotary disk system is located in the first filtration tank; the second fiber rotary disk filtration system is located in the second filtration tank; the first fiber rotary disk filtration system includes a first fiber rotary disk filter; the second fiber rotary disk filtration system includes a second fiber rotary disk filter; the filtration aperture of the filter cloth in the first fiber rotary disk filter is 15-30 μm; the filtration aperture of the filter cloth in the second fiber rotary disk filter is 1-5 μm; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system respectively include a backwashing system and a supporting electrical control system; the outlet of the aquaculture pond is communicated with the first filtration tank and the second filtration tank respectively through pipelines; the filtered water outlet of the fiber rotary disk filtration system is communicated with the inlet of the aquaculture pond through a pipeline.

[0039] In the present invention, the outlet of the aquaculture pond flows into the first filtration tank or the second filtration tank by gravity through a pipeline, and an electric valve is preferably arranged on the pipeline.

[0040] In the present invention, the fiber rotary disk filter preferably includes a central drum and a rotary disk; the rotary disk is fixed around the central drum and communicated with the central drum through a communication hole; filter cloths are installed on both sides of the rotary disk; the base cloth of the filter cloth is preferably polyester fiber, and the fluff on the base cloth is preferably polyamide fiber.

[0041] In the present invention, the filtration fluxes of the first fiber rotary disk filtration system and the second fiber rotary disk filtration system for the same aquaculture wastewater are equal to maintain the constant water level in the fish pond; the number of rotary disks of the first and second fiber rotary disk filters is determined according to the amount of aquaculture wastewater to be treated.

[0042] In the present invention, the filtration pore diameter of the filter cloth in the first fiber rotary disk filter is 1 - 5 μm, preferably 1 μm; the filtration pore diameter of the filter cloth in the second fiber rotary disk filter is 15 - 30 μm, preferably 30 μm.

[0043] In the present invention, a first filter pond water inlet is preferably provided on the pool wall of the first filter pond, and a second filter pond water inlet is preferably provided on the pool wall of the second filter pond; a filtered water collection trough is preferably provided between the first filter pond and the second filter pond, and a filtered water outlet is provided at the bottom of the filtered water collection trough; sewage outlets are respectively provided at the bottoms of the first filter pond and the second filter pond; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system share a filtered water collection trough and a filtered water outlet.

[0044] In the present invention, the fiber rotary disk filtration system preferably further includes a sludge discharge system; the sludge discharge system preferably includes sludge discharge pipes respectively provided at the bottoms of the first filter pond and the second filter pond, and the sludge discharge pipes are communicated with a reverse suction pump through pipelines.

[0045] In the present invention, electric valves are preferably provided on the sludge discharge pipes in the first filter pond and the second filter pond respectively; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system preferably share a reverse suction pump.

[0046] In the present invention, the filtered water outlet of the fiber rotary disk filtration system is communicated with the water inlet of the fish pond through a pipeline, and a water pump is preferably provided on the pipeline.

[0047] In the present invention, the first fiber rotary disk filter system and the second fiber rotary disk filter system can operate independently but cannot be opened synchronously; the water inlet of the first fiber rotary disk filter system and the second fiber rotary disk filter system are controlled by electric valves respectively. During the cultivation of microalgae, the first fiber rotary disk filter system with a filter aperture of 15 to 30 μm is turned on, and the microalgae can return to the fish pond through the first fiber rotary disk filter to continue cultivation; large-size particles such as fish feces and leftover bait will either sink directly to the bottom or be intercepted by the filter cloth of the first fiber rotary disk filter and discharged through the backwashing system and the mud discharge system. When it is necessary to remove the microalgae in the aquaculture water body, the second fiber rotary disk filter system with a filter aperture of 1 to 5 μm is turned on for interception, and the microalgae are discharged through the backwashing system. After the microalgae in the water body are removed, the pre-cultured high-activity microalgae needs to be added again.

[0048] In the present invention, during the filtration process of the fiber rotary filter system, large-size particles in the sewage are blocked by the filter cloth, and clean water flows through the filter cloth, flows into the central drum by gravity, and then flows out of the fiber rotary filter system through the filtered water outlet; the large-size particles blocked by the filter cloth, part of which adhere to the surface of the filter cloth, and the other part sinks to the bottom of the pool. As the attachments on the filter cloth increase, the filtration resistance increases, and the water level of the filter pool gradually rises. When the liquid level reaches the backwashing set value, the matching electrical control system starts the back suction pump and starts the backwashing process. During normal filtration, the rotary disk is in a stationary state, which is conducive to the direct sinking of the aquaculture sewage particles.

[0049] In the present invention, during the backwashing process of the fiber rotary disk filter system, the rotary disk rotates at a speed of about 1 r / min, and the matching electrical control system controls the electric valve connected to the back-suction pump pipeline to clean each group of rotary disks in turn; the back-suction pump negatively sucks the surface of the filter cloth, and the clean water passing through the filter cloth cleans the filter cloth from the inside to the outside, and the sludge accumulated on the filter cloth is washed off and discharged in turn through the back-suction pump and the sewage outlet. After all the rotary disks are cleaned, the liquid level in the filter tank returns to normal. During the backwashing period, filtration is carried out as usual, and the backwash water volume only accounts for about 1% of the filtered water volume.

[0050] In the present invention, the mud discharge system preferably includes mud discharge pipes respectively arranged at the bottom of the first filter tank and the second filter tank, and the mud discharge pipes are connected to the back-suction pump through pipelines; the mud discharge pipes in the first filter tank and the second filter tank are preferably respectively provided with electric valves; the back-suction pump is preferably equipped with an electrical control system, which can start the mud discharge system according to the working conditions.

[0051] In the present invention, the sewage discharge component is used to discharge sludge.

[0052] In the present invention, the sunlight factory recirculating aquaculture system preferably further includes a soluble pollutant removal system and a disinfection system. The present invention does not have special limitations on the soluble pollutant removal system and the disinfection system, and conventional soluble pollutant removal systems and disinfection systems in the art can be used; in the specific implementation process of the present invention, the disinfection system includes ozone and ultraviolet disinfection.

[0053] In the present invention, the sunlight factory recirculating aquaculture system preferably further includes an automatic on-line monitoring system, and the automatic on-line monitoring system includes swimming behavior and feeding status, which can ensure the safety of the aquaculture water body on the fish; the automatic on-line monitoring system real-time on-line detects the feeding behavior, dissolved oxygen, pH, water temperature and residual chlorine in the fish pond body.

[0054] The present invention also provides a sunlight factory recirculating aquaculture method based on the sunlight factory recirculating aquaculture system described in the above solution, including the following steps:

[0055] 1) Inject water into the fish pond body and add pre-domesticated microalgae seeds; the dosage of the microalgae seeds is 50-1000 mg / L of water body;

[0056] 2) Release fry and feed the fish pond every 3-5 hours;

[0057] 3) During the aquaculture process, when the microalgae are at the end of the stable growth period and are about to enter the decline period, close the first fiber rotary disk filter, open the second fiber rotary disk filter, so that the microalgae cannot return to the fish pond again, and the intercepted microalgae are discharged through the backwashing system, and add a certain volume of pre-cultured highly active microalgae to make the algae density in the aquaculture water body 50-1000 mg / L, and harvest the fish after 150-200 days.

[0058] The present invention first injects water into the fish pond body and adds pre-domesticated microalgae seeds to make the algae density in the aquaculture water body 50-1000 mg / L.

[0059] In the present invention, the inlet water is preferably tap water, and the inlet water speed of the inlet water is preferably 60 m 2 / h; in the present invention, when the water surface height in the fish pond is 15-25 cm away from the top of the fish pond, the water inlet is completed; at 100 m 3Taking a fish pond body with a certain volume as an example, the time for water inlet to be completed is preferably 1 - 2 hours, more preferably 1.5 hours. After the water inlet is completed in the present invention, pre-cultured microalgae are added until the algal density in the aquaculture water body reaches 50 - 1000 mg / L, preferably 100 - 500 mg / L, and more preferably 200 mg / L. After adding the microalgae is completed, the first fiber rotary disk filtration system is started. After running for 1 - 2 hours, fry are put into the fish pond. There are no special limitations on the types of the fry in the present invention, and any conventional cultured fish in the field can be used. In the specific implementation process of the present invention, the varieties of the fry include salmon, yayu, rainbow trout, starry grouper, sea bass or mandarin fish. In the present invention, the stocking density of the fry is preferably 25 - 35 kg / m 3 , more preferably 28 - 32 kg / m 3 , and most preferably 30 kg / m 3 .

[0060] In the present invention, the microalgae can pass through the filter cloth in the first fiber rotary disk filter, but cannot pass through the filter cloth in the second fiber rotary disk filter.

[0061] In the present invention, the microalgae are cultured using the photo-fermentation system; taking the photo-fermentation culture of Chlorella as an example, 10 L of Chlorella seeds are inoculated into a 100 L fermenter filled with sterilized medium. The light intensity increases continuously from 200 μmol / (m 2 .s) to 500 μmol / (m 2 ·s) according to the change of cell density. The pH of the medium is 6.0, the temperature is 30 °C, the stirring speed is 150 r / min, the ventilation volume is 200 L / min, and the culture ends after 120 h. The feeding method during the culture process is: according to the growth situation of Chlorella, several liters of 500 g / L glucose mother liquor are added once every 12 h to ensure that the glucose concentration in the medium is 20 - 25 g / L; 1 mol / L concentrated nitric acid is automatically added as the nitrogen source.

[0062] In the present invention, the preferred microalgae include one or more of Chlorella, Nannochloropsis, Dunaliella, and Chlamydomonas reinhardtii. Microalgae are a type of single-celled algae with a small volume, simple structure, rapid growth and reproduction, and have the advantages of high photosynthesis efficiency, strong environmental adaptability, and high biological yield.

[0063] After adding pre-domesticated microalgae seeds, the present invention releases fry and feeds the fish pond every 3.5 - 4.5 hours.

[0064] In the present invention, when the fry are salmon, when the weight of more than 80% of the single fish is 20 g, the initial water inflow rate is preferably 30 - 35 m 3 / h, and more preferably 35 m 3 / h, when the weight of more than 80% of single fish is 100 g, the initial inflow rate is preferably 35 - 40 m 3 / h, more preferably 40 m 3 / h; when the weight of more than 80% of single fish is 200 - 500 g, the initial inflow rate is preferably 45 - 50 m 3 / h, more preferably 50 m 3 / h; when the weight of more than 80% of single fish is 500 - 2000 g, the initial inflow rate is preferably 50 - 60 m 3 / h, more preferably 60 m 3 / h, when the weight of more than 80% of single fish is 2000 - 3500 g, the initial inflow rate is preferably 60 - 70 m 3 / h, more preferably 70 m 3 / h. When the fry is Schizothorax prenanti, the initial inflow rate is preferably controlled at 28 - 32 m 3 / h, more preferably 30 m 3 / h, the initial outflow rate is preferably 28 - 32 m 3 / h, 30 m 3 / h. In the present invention, with the growth of the cultured fry, different water inflow and outflow rates are set according to the density of the cultured fish body. When the culture density in the water body is greater than or equal to 30 kg / m 3 , and less than 60 kg / m 3 , the water inflow and outflow are respectively set to 35 - 45 m 3 / h, preferably 38 - 42 m 3 / h, more preferably 40 m 3 / h; when the culture density in the water body is greater than or equal to 60 kg / m 3 , and less than 100 kg / m 3 , the water inflow and outflow are respectively set to 55 - 65 m 3 / h, preferably 58 - 62 m 3 / h, more preferably 60 m 3 / h; when the culture density in the water body is greater than or equal to 100 kg / m 3 , and less than 200 kg / m 3 , the water inflow and outflow are respectively set to 70 - 90 m 3 / h, preferably 75 - 85 m 3 / h, more preferably 80 m 3 / h.

[0065] In the present invention, when the culture density in the water body is greater than or equal to 30 kg / m 3 , and less than 60 kg / m 3 , the water inflow and outflow are respectively set to 35 - 45 m 3 / h; When the aquaculture density in the water body is greater than or equal to 60 kg / m 3 , and less than 100 kg / m 3 , the water inflow and outflow are respectively set to 55 - 65 m 3 / h; When the aquaculture density in the water body is greater than or equal to 100 kg / m 3 , and less than 200 kg / m 3 , the water inflow and outflow are set to 70 - 90 m 3 / h.

[0066] In the present invention, during the aquaculture process, the dissolved oxygen content in the aquaculture water body is 5 - 12 mg / L.

[0067] In the present invention, it is preferred to feed the fish pond every 4 h. In the present invention, when the single fish weight is 30 - 50 g, the feeding amount of the feed is preferably 2.5% - 3% of the total weight of the fish in the aquaculture water body; the dosage of the algal species is preferably 800 - 1200 L / 100 m 3 water body; when the single fish weight is 200 - 500 g, the feeding amount of the feed is preferably 2% - 2.5% of the total weight of the fish in the aquaculture water body.

[0068] During the aquaculture process, when the microalgae are at the end of the stable growth phase and about to enter the decline phase, the first fiber rotary disk filter is closed and the second fiber rotary disk filter is opened, so that the microalgae cannot return to the fish pond again, and the intercepted microalgae are discharged through the backwashing system. A certain volume of pre-cultured highly active microalgae is added to make the algal density in the aquaculture water body 50 - 1000 mg / L, and the fish are harvested after 150 - 200 d.

[0069] In the present invention, the addition of microalgae has multiple effects. On the one hand, microalgae can effectively remove soluble pollutants such as nitrogen and phosphorus in the water body. After adding microalgae, microalgae can use soluble pollutants such as nitrogen and phosphorus in the water body as nutrients to achieve the growth and reproduction of microalgae in the water body; on the other hand, the growth and reproduction of microalgae can release oxygen, and the released oxygen can be utilized by the fish in the water body, thereby reducing the demand for artificial oxygenation. Further, Chlorella also has an inhibitory effect, which can inhibit the growth of harmful bacteria in the water body, maintain the water environment, and prevent the fish in the water body from being infected with harmful bacteria; in addition, the microalgae added to the water body can also be used as fish feed for fish to eat; at the same time, the polysaccharides produced on the surface of microalgae can agglomerate and wrap nearby insoluble particulate pollutants, which can increase the particle size and further promote the sedimentation of particulate pollutants, facilitating the rapid separation of particulate pollutants.

[0070] During the breeding process of the present invention, oxygen is added to the fish-algae breeding system through an oxygenation cone. The present invention determines whether oxygenation is required based on the concentration of dissolved oxygen; the dissolved oxygen in the fish-algae breeding system is maintained above 7.0 mg / L; when the dissolved oxygen in the fish breeding system is lower than 7.0 mg / L, oxygenation is carried out.

[0071] The present invention harvests after 150 - 200 days of fish breeding. In the present invention, when the fish is rainbow trout, the weight of the fry put in is 4.5 - 5.5 g, preferably harvested after 170 - 190 days of breeding, and the weight of the harvested rainbow trout is 450 - 550 g. When the fish is salmon, the weight of the fry put in is 4.5 - 5.5 g, and the weight of the harvested salmon is 2000 - 3600 g.

[0072] In the present invention, the industrialized fish-algae recirculating aquaculture using the breeding system, during the breeding process, microalgae are regularly added to the fish-algae breeding system. The microalgae convert nutrients such as CO2, nitrogen, and phosphorus in the water into algal cells and convert them into their own substances, purifying the water quality in the fish pond, and using the fiber rotary disk filtration system to fully remove particulate matter, macromolecular proteins, algae, bacteria, viruses, etc. in the aquaculture water body, realizing the recycling of aquaculture sewage, and the sewage discharge is zero; it can truly achieve high-density, high-stability, and low-energy-consumption recirculating aquaculture.

[0073] The following combines examples to elaborate on the technical solutions provided by the present invention in detail, but they cannot be understood as limiting the protection scope of the present invention.

[0074] Example 1

[0075] A sunlight industrialized recirculating aquaculture system, the structure of the fish pond is as Figure 1 shown, where 1 - fish pond body, 2 - water inlet, 3 - water outlet, 4 - outlet valve, 5 - water pump, 21 - first filter pond water inlet, 22 - second filter pond water inlet, 23 - first filter pond, 24 - second filter pond, 25 - first fiber rotary disk filtration system, 26 - second fiber rotary disk filtration system, 27 - filtered water collection tank, 28 - filtered water outlet, 29 - supporting electrical control system.

[0076] The schematic diagram of the sludge discharge system of the fiber rotary disk filtration system is as Figure 2 shown, where 21 - first filter pond water inlet, 22 - second filter pond water inlet, 23 - first filter pond, 24 - second filter pond, 28 - filtered water outlet, 30 - sewage suction port, 31 - reverse suction pump, 32 - sewage suction pipe;

[0077] The method of culturing fish using the sunlight industrialized recirculating aquaculture system in Example 1:

[0078] Under normal circumstances, it is fed 3 times, at 8 am, 1 pm, and 6 pm. For salmon, the feeding ability of the fish is better when the water temperature is controlled between 14 and 18 degrees Celsius.

[0079] Table 1 Data of fish cultured using the sunlight industrialized recirculating aquaculture system of this embodiment

[0080]

[0081]

[0082] Comparative experiment:

[0083] Conventional fish ponds: pond culture, cement pond culture, and cage culture.

[0084] Cultivation method: Conventional cultivation is fed 2 times a day, and the water temperature cannot be controlled and changes according to the weather conditions.

[0085] Table 2 Data of fish cultured in conventional fish ponds

[0086]

[0087]

[0088] It can be seen that both the single weight and density of the fish cultured using the sunlight industrialized recirculating aquaculture system provided in the present invention are significantly greater than those of conventional cultivation.

[0089] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for sunlight factory recirculating aquaculture based on a sunlight factory recirculating aquaculture system, The sunlight factory recirculating aquaculture system includes a fishpond and a fiber rotary disk filtration system; The fishpond includes: The fishpond body, the water inlet and the water outlet; The fiber rotary disk filtration system includes a first fiber rotary disk filtration system and a second fiber rotary disk filtration system; The first fiber rotary disk system is located in the first filtration pond; The second fiber rotary disk filtration system is located in the second filtration pond; The first fiber rotary disk filtration system includes a first fiber rotary disk filter; The second fiber rotary disk filtration system includes a second fiber rotary disk filter; The filter cloth filtration pore size in the first fiber rotary disk filter is 15 - 30 μm; The filter cloth filtration pore size in the second fiber rotary disk filter is 1 - 5 μm; The first fiber rotary disk filtration system and the second fiber rotary disk filtration system respectively include a backwashing system and a supporting electrical control system; The water outlet of the fishpond is connected to the first filtration pond and the second filtration pond respectively through pipelines; The filtered water outlet of the fiber rotary disk filtration system is connected to the water inlet of the fishpond through a pipeline; The method for sunlight factory recirculating aquaculture includes the following steps: 1) Inject water into the fishpond body and add pre-cultured highly active microalgae until the algae density in the aquaculture water body reaches 50 - 1000 mg / L; 2) Release fry and feed the fishpond every 3 - 5 h; 3) During the microalgae cultivation period, turn on the first fiber rotary disk filtration system with a filtration pore size of 15 - 30 μm. The microalgae can return to the fishpond through the first fiber rotary disk filter and continue to be cultivated; large particle size substances either sink to the bottom directly or are intercepted by the filter cloth of the first fiber rotary disk filter and are discharged through the backwashing system and the sludge discharge system; during the cultivation process, when the microalgae are at the end of the stable growth period and about to enter the decline period, turn off the first fiber rotary disk filter and turn on the second fiber rotary disk filtration system with a filtration pore size of 1 - 5 μm for interception, and the microalgae are discharged through the backwashing system; add a certain volume of pre-cultured highly active microalgae to make the algae density in the aquaculture water body reach 50 - 1000 mg / L, and harvest the fish after 150 - 200 days.

2. The method for culturing fish in a sunlight factory recirculating water according to claim 1, wherein The filtration fluxes of the first fiber rotary disk filtration system and the second fiber rotary disk filtration system for the same aquaculture sewage are equal.

3. The method for culturing fish in a sunlight factory circulating water according to claim 1 or 2, characterized in that, A filtered water collection tank is arranged between the first filtration pond and the second filtration pond; a filtered water outlet is arranged at the bottom of the filtered water collection tank; sewage outlets are respectively arranged on the first filtration pond and the second filtration pond; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system share a filtered water collection tank and a filtered water outlet.

4. The method for raising fish in a sunlight factory recirculating water according to claim 1, characterized in that, The fiber rotary disk filtration system further includes a sludge discharge system; the sludge discharge system includes sludge discharge pipes respectively arranged at the bottoms of the first filtration pond and the second filtration pond, and the sludge discharge pipes are connected to a reverse suction pump through pipelines.

5. The method for culturing fish in a sunlight factory circulating water according to claim 4, characterized in that Electric valves are respectively arranged on the sludge discharge pipes in the first filtration pond and the second filtration pond; the first fiber rotary disk filtration system and the second fiber rotary disk filtration system share a reverse suction pump.

6. The method for raising fish in a sunlight factory recirculating water according to claim 1, characterized in that, The aquaculture density is 25 - 35 kg / m³.

7. The method for raising fish in a sunlight factory recirculating water according to claim 1, characterized in that When the aquaculture density in the water body is greater than or equal to 30 kg / m³ and less than 60 kg / m³, the water inflow and outflow are respectively set to 35 - 45 m³ / h; when the aquaculture density in the water body is greater than or equal to 60 kg / m³ and less than 100 kg / m³, the water inflow and outflow are respectively set to 55 - 65 m³ / h; when the aquaculture density in the water body is greater than or equal to 100 kg / m³ and less than 200 kg / m³, the water inflow and outflow are set to 70 - 90 m³ / h.

8. The method for culturing fish in a sunlight factory recirculating water according to claim 1, characterized in that During the aquaculture process, the dissolved oxygen content in the aquaculture water body is 5 - 12 mg / L.

9. The method for culturing fish in a sunlight factory recirculating water according to claim 1, characterized in that, The microalgae can pass through the filter cloth in the first fiber rotary disk filter and cannot pass through the filter cloth in the second fiber rotary disk filter; the microalgae include one or several of Chlorella vulgaris, Nannochloropsis, Dunaliella salina, and Chlamydomonas reinhardtii.

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