Low-consumption circulating aquaculture system based on built-in perforated pipe biological filter bed

Abstract

The invention provides a low-consumption circulating aquaculture system based on a built-in perforated pipe biological filter bed, and relates to the field of sewage treatment. The breeding system comprises a breeding container, and a filtering assembly is arranged at the bottom in the breeding container; a filter bag is arranged in the filter container; the water outlet of the filter assembly is communicated with the water inlet of the filter bag, and the water outlet of the filter bag is communicated with the top of the breeding container. The system is low in sewage treatment energy consumption, small in occupied area and high in treatment efficiency.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and more particularly, to a low-consumption circulating water aquaculture system based on an in-built porous tube biological filter bed. Background Art

[0002] The working principle of a traditional external circulating water treatment system is to pump the sewage at the bottom of the aquaculture pond to an external treatment unit (such as a sedimentation tank, a mechanical filter, a fluidized bed biological filter, an ozone / ultraviolet disinfection device, etc.), and the treated clear water is returned to the aquaculture pond. Physical filtration: large particulate suspensions are removed by using sieves (drum or flat type) brushes, protein skimmers, etc.; biological filtration: nitrifying bacteria are cultured through carriers such as fluidized beds and biological rotating discs to degrade ammonia nitrogen and nitrite; chemical treatment: flocculants or ozone are added to oxidize and decompose organic matters; disinfection and sterilization: ultraviolet rays or ozone are used to kill pathogenic microorganisms.

[0003] The advantages of the external circulating water treatment system are as follows: modular design, which is convenient for treating pollutants in stages; high treatment efficiency of biological filters such as fluidized beds (ammonia nitrogen removal rate > 90%); suitable for large-scale industrial farms. Disadvantages: large floor area, and additional facilities such as sedimentation tanks and filtration bins need to be built; high energy consumption, and the comprehensive power consumption of multi-stage water pumps, fluidized bed aeration and other equipment is large (power consumption per ton of water > 1.5 kW·h); frequent maintenance, the filter media needs to be cleaned regularly when blocked (such as daily cleaning of the protein skimmer), and carriers need to be supplemented for the fluidized bed; high cost, high equipment investment (such as ozone generators) and operation and maintenance costs (electricity bills, chemicals).

[0004] The working principle of a compound artificial wetland is to divert the aquaculture wastewater to the artificial wetland, and the water quality is purified through the synergistic action of plant roots, microorganisms and substrates (such as gravel and zeolite). Advantages: almost zero energy consumption and environmentally friendly; economic crops (such as rice and aquatic vegetables) can be produced synchronously. Disadvantages: extremely large floor area: the wetland area required to treat 1 ton of water > 10m 2 ; low efficiency: the ammonia nitrogen removal period is as long as several weeks, and it cannot support high-density aquaculture; season dependence: the treatment efficiency drops sharply in winter in low-temperature regions.

[0005] Therefore, there is an urgent need to provide a circulating water treatment system with low energy consumption, environmental friendliness, high treatment efficiency and small floor area. Summary of the Invention

[0006] The purpose of the present invention is to provide a low-consumption circulating water aquaculture system based on an in-built porous tube biological filter bed, which has low energy consumption, small floor area and high treatment efficiency for treating sewage.

[0007] The present invention solves its technical problems by adopting the following technical solutions.

[0008] On the one hand, an embodiment of the present invention provides a low-consumption circulating water aquaculture system based on an in-built porous tube biological filter bed, including an aquaculture container, wherein a filtering component is arranged at the bottom inside the aquaculture container; a filtering container, wherein a filtering bag is arranged inside the filtering container; the water outlet of the filtering component is communicated with the water inlet of the filtering bag, and the water outlet of the filtering bag is communicated with the top of the aquaculture container.

[0009] In some embodiments of the present invention, the filtering component includes a water outlet pipe having a plurality of through holes, and a filter media layer laid on the top of the water outlet pipe. The water outlet pipe can be a PVC pipe, and the through holes are arranged in the circumferential direction of the water outlet pipe. When the water circulates, the water in the aquaculture container can enter the filtering container through the water outlet pipe.

[0010] In some embodiments of the present invention, the filter media layer includes a nitre layer and a ceramsite layer laid in sequence from top to bottom. The volume of the filter media layer is 20%-30% of the volume of the aquaculture container.

[0011] The ratio of nitre to ceramsite is related to the nitrification and denitrification capabilities. Nitrification activity (in an aerobic environment) depends on the number of nitrifying bacteria attached to the surfaces of nitre and ceramsite, showing a direct proportional relationship. Denitrification activity (in an anaerobic environment) is directly proportional to the internal volume of ceramsite. The larger the internal volume, the larger the number of denitrifying bacteria colonies and the stronger the denitrification ability. Therefore, it is directly proportional to the aquaculture density. The higher the aquaculture density, the higher the proportion of nitre and ceramsite should be accordingly.

[0012] Surface area of ceramsite (diameter 30mm): approximately 0.0028 square meters;

[0013] Total surface area of one cubic meter of ceramsite:

[0014] Theoretical value (without pores): approximately 200 square meters

[0015] Actual value (porosity 30%): approximately 140 square meters.

[0016] The particle size of the ceramsite is 20-30mm, the particle size of the nitre is 30-50mm, and the large porosity of the nitre is 20%-30%. It should be noted that the nitre used in the embodiments of the present invention is a material used in construction. It is used in building buildings, roads, equipment foundations, etc. When mixed with cement, sand, and water, it can form "concrete". In the construction industry, there are generally three stone diameter specifications: 10-30mm, 20-40mm, 30-50mm. It should be noted that in this application, "nitre" refers to the crushed stone of granite specifications, mainly containing quartz and feldspar, belonging to silicate minerals, and usually showing a neutral to weak alkaline. Granite belongs to acidic plutonic rock and is mainly composed of the following three minerals:

[0017] 1. Quartz (SiO2) content: 20% - 40% Properties: High hardness (Mohs hardness 7), chemically stable, resistant to acids and alkalis, and is the main source of granite strength.

[0018] Feldspar group:

[0019] Potassium feldspar (KAlSi3O8): Content 30% - 50%, providing the light color tone of granite.

[0020] Plagioclase (NaAlSi3O8 - CaAl2Si2O8): Content 10% - 30%, with a color ranging from grayish - white to light green.

[0021] Mica group:

[0022] Biotite (K(Mg,Fe)3AlSi3O 10 (F3OH)2): Content 5% - 15%, in flake form, which may reduce the compressive strength of the aggregate.

[0023] Muscovite (KAl2(AlSi3O 10 )(OH)2): Content is relatively low (<5%).

[0024] Minor minerals, such as amphibole, pyroxene, magnetite, etc. (total content <5%).

[0025] The ceramsite and stone nitre in the present invention can provide sufficient attachment area for microorganisms. There are a large number of micropores on the surface and inside of the ceramsite, providing a large number of attachment sites for beneficial microorganisms such as nitrifying bacteria. Stone nitre and ceramsite can not only physically intercept suspended matters such as feces and residual baits (particle size >100μm), but also form a biofilm on their surfaces, mainly nitrifying bacteria, which gradually oxidize ammonia nitrogen (NH3) to nitrate (NO3 - ). The concentration of nitrate (NO3 - ) in the aquaculture container can be maintained at a safe threshold of <100mg / L through low - frequency water change and micro - scale denitrification in the system; the pH value is stable (7.0 - 8.5) and is jointly regulated by microbial metabolism and the water body buffering capacity (such as the carbonate system).

[0026] In traditional recirculating aquaculture systems, the carbonate equilibrium system is the core chemical buffering system for maintaining water quality stability. Aquatic animals metabolize to produce CO2, which dissolves to form H2CO3, increasing the H + concentration (lowering the pH). Alkalinity is consumed during nitrification: NH4 + +2O2→NO3 - +2H + +H2O; for every 1mg of NH4 +It consumes 7.14 mg of CaCO3 alkalinity, and at this time, it is necessary to supplement carbonate for buffering. However, in this application, the ceramsite at the bottom of the aquaculture container can play a role in self-regulation and buffering, so this system does not need to supplement carbonate for artificial pH adjustment.

[0027] It should be noted that in the present invention, ceramsite is a kind of lightweight and porous artificial aggregate. It is made by high-temperature roasting and expansion, and basically sold in the building materials market is an environmentally friendly recycled material (industrial waste), which is fired from raw materials such as fly ash, coal gangue and sludge. The basic parameters of this type of ceramsite are as follows:

[0028] Compressive strength (extrusion strength): 1.5 - 10 MPa,

[0029] Bulk density: 300 - 1000 kg / m 3 (It has significant lightweight characteristics, about 1 / 3 of ordinary sand and gravel).

[0030] Apparent density: 600 - 1800 kg / m 3 (The higher the porosity, the lower the density).

[0031] pH value range: 7 - 9 (weakly alkaline), because the raw materials contain metal oxides (such as CaO, MgO) which form alkaline compounds after roasting.

[0032] The physical structure (porous adsorption) and weak alkalinity of ceramsite play a partial buffering role in pH fluctuations, but it is difficult to solely rely on it to form a stable carbonate buffer system. During the operation of water treatment, it is necessary to combine with water quality monitoring and add NaHCO3 or Ca(OH)2 when necessary to effectively maintain the pH stability of the aquaculture water body. When designing the system, there is a reserved alkalinity adjustment interface, and its adaptability is adjusted according to the specific water quality.

[0033] In the recirculating aquaculture system, when ceramsite is used as the biochemical bed filter material, its unique physical structure can indeed provide conditions for denitrification by forming an aerobic biofilm on the outer surface and an anaerobic microenvironment with a porous network structure inside.

[0034] The construction of the ceramsite structure for the denitrification environment:

[0035] (1) Anaerobic micro-units with a porous network structure

[0036] Physical characteristics: There are a large number of micropores and channels inside the ceramsite (the pore diameter is usually in the range of micrometers to millimeters). When water flows through, the external water flow velocity is relatively fast and the dissolved oxygen (DO) is sufficient (aerobic zone); while due to mass transfer limitation in the internal pores, oxygen is difficult to diffuse deeply, gradually forming a locally anoxic / anaerobic environment.

[0037] Micro-unit formation: The pores inside each ceramsite can be regarded as independent "anaerobic micro-units". After multiple ceramsites are stacked, these micro-units together form a decentralized anaerobic zone group, providing a habitat for denitrifying bacteria.

[0038] (2) Stratified function of biofilm

[0039] Outer layer (aerobic zone): The surface of the ceramsite is rough. The outer layer of the biofilm is mainly composed of nitrifying bacteria (such as Nitrosomonas and Nitrobacter), which are responsible for oxidizing ammonia nitrogen (NH3 / NH4 + ) to nitrite (NO2 - ) and then further oxidizing it to nitrate (NO3 - ).

[0040] Inner layer (anaerobic zone): The dissolved oxygen in the deep pores approaches zero. Denitrifying bacteria (such as Pseudomonas and Paracoccus denitrificans) use nitrate (NO3 - ) as an electron acceptor and gradually reduce NO3 - to nitrogen gas (N2) to complete the denitrification process.

[0041] The large particle size (30 - 50 mm) and loose packing of stone nitre form a high porosity, with low water flow resistance, avoiding the formation of anaerobic zones; the continuous long-term large flow of water passing through the gaps of the stacked stone nitre continuously scours, inhibiting the hardening of the filter media layer.

[0042] In some embodiments of the present invention, a booster pump is further included, and the booster pump is arranged between the breeding container and the filtering container. Through the booster pump, the water in the breeding container is pumped into the filtering container to realize the circulation of the water body. On the other hand, a 150W water pump (flow rate 40t / h) forcibly pumps water from the porous pipes in parallel arrays at a pressure of 0.08 - 0.15 Mpa and sends it to the filtering container. After being filtered by the filter bag, it returns to the breeding barrel. The water flow penetrates the filter media layer from the bottom of the breeding container to ensure the uniform distribution of dissolved oxygen (DO) (>5 mg / L) and promote the activity of aerobic bacteria. And under the action of the booster pump, the large flow of water scours the gaps of the stone nitre, which can prevent blockage caused by the deposition of organic matter and maintain the porosity of the filter media.

[0043] More preferably, in some embodiments of the present invention, the filter bag used is a pressure-bearing self-cleaning 200-mesh filter bag: 40 PP cotton filter bags (diameter 200 mm, length 1500 mm) intercept micro-particles (<75 μm) such as bacterial clusters and colloidal organic matter to reduce the turbidity of the water body. Vine cotton is arranged at the end of the filter bag to adjust the pressure fluctuation through elastic deformation, avoiding the destruction of the filter bag structure by high-pressure impact and prolonging the service life.

[0044] In some embodiments of the present invention, an overflow pipe for collecting floating impurities is further arranged at the top of the breeding container.

[0045] In some embodiments of the present invention, a feed feeding device is further provided above the breeding container.

[0046] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0047] The circulating water aquaculture system provided by the present invention is provided with a filtering component at the bottom of the breeding container, which can block and filter the water flow. Larger particulate impurities such as residual bait and feces will be intercepted in the gaps between ceramsite and nitre, achieving preliminary physical filtration and reducing the content of impurities entering the subsequent filtration link. The aperture of the filter bag in the filter container is small, which can further filter out tiny particulate impurities, plankton, bacteria and smaller organic particles in the water, making the water quality clearer.

[0048] In this circulating water aquaculture system, the filtering component is arranged inside the breeding container, which has a small floor area. Under the action of the filtering component and the filter bag, the water body in the breeding container is filtered to remove impurities in the water, with low energy consumption, and only needs to circulate the water under the action of a water pump.

[0049] The aquaculture system provided by the present invention can achieve ultra-high-density aquaculture: supporting a breeding density of 20 - 50 kg / m 3 (the traditional earthen pond aquaculture is only 1 - 5 kg / m 3 ), and the output per unit water body is increased by 6 - 10 times.

[0050] Very low maintenance cost: Cases from 2004 to the present show that: without cleaning the filter media, only relying on the operation of the water pump (150W, daily power consumption is about 3.6 KWh), the comprehensive operation and maintenance cost is more than 50% lower than that of today's circulating water system.

[0051] Water quality stability: ammonia nitrogen < 0.2 mg / L, nitrite < 0.05 mg / L, the disease risk is reduced by 80%, the use of antibiotics is reduced, meeting the green aquaculture standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0053] Figure 1 It is a schematic diagram of the aquaculture treatment system of the embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the filter container of the aquaculture treatment system of the embodiment of the present invention;

[0055] Figure 3 Schematic diagram of the aquaculture container of the aquaculture treatment system according to the embodiment of the present invention;

[0056] Icons: 1 - aquaculture container, 2 - filtration container, 3 - booster water pump, 4 - water replenishing device, 5 - ozone mixing device, 6 - filter bag, 7 - stone nitrate layer, 8 - ceramsite layer, 9 - overflow pipe, 10 - feed feeder, 11 - water outlet pipe, 12 - aerator, 13 - automatic dissolved oxygen regulator, 14 - water level pressure transmitter, 15 - intelligent controller. Specific embodiments

[0057] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0058] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to specific embodiments.

[0059] Embodiment 1

[0060] Referring to the accompanying drawings, an embodiment of the present invention provides a low-consumption circulating water aquaculture system based on an in-built porous tube biological filter bed:

[0061] An aquaculture container, a PP aquaculture pond with a diameter of 6 meters and a height of 2 meters, and a filtration component is provided at the bottom of the aquaculture container; the filtration component includes a PVC water outlet pipe with a plurality of through holes, and a filter material layer laid on top of the water outlet pipe.

[0062] Among them, PVC pipes are laid every 300 mm, and the midpoint of each pipe length is the parallel point of the pipe network. The aperture of the PVC pipe is 3 mm, and the center distance between the rows and columns of the holes is 20 mm. Each pipe is drilled with three rows and three columns of holes to form a uniform water flow channel to avoid local siltation. The filter material layer includes a stone nitrate layer and a ceramsite layer laid in sequence from top to bottom, and the stone nitrate layer and the ceramsite layer respectively account for 10% of the volume of the aquaculture container. The particle size of the ceramsite is 20 - 30 mm, the particle size of the stone nitrate is 30 - 50 mm, and the large porosity of the stone nitrate is 20 - 30%. At the top of the aquaculture container, an overflow pipe is provided, which is directly purchased from the market and is used to collect floating impurities on the water surface of the aquaculture container. A feed feeding device is also provided at the top of the aquaculture container for feeding feed into the aquaculture container, and the feed feeder is directly purchased from the market.

[0063] Filter container, a filter bag is arranged inside the filter container; the water outlet of the PVC water outlet pipe of the filter component is communicated with the water inlet of the filter bag through a pipeline, and a booster pump is arranged on the pipeline; the water outlet of the filter bag is communicated with the top of the aquaculture container through a pipeline. The filter bag used is a pressure-bearing self-cleaning 200-mesh filter bag: 40 PP cotton filter bags (diameter 200 mm, length 1500 mm) intercept micro-particles <75 μm (such as bacterial clusters, colloidal organic matters), reducing the turbidity of the water body. Vine cotton is arranged at the end of the filter bag, and the pressure fluctuation is adjusted through elastic deformation to avoid the destruction of the filter bag structure by high-pressure impact and extend the service life. The power of the booster pump is 150 w, the flow rate is 40 t / h, the water pressure is 0.15 Mpa, and the pressure filter bag: a pressure-bearing self-cleaning 200-mesh filter bag.

[0064] It also includes an ozone mixing device, which is arranged after the filter container. The water treated by the filter container then passes through the ozone mixing device, ozone is added to the water, and then it flows back into the aquaculture container.

[0065] It also includes a water replenishing device and a flow transmitter, which are arranged after the aquaculture container. The sewage in the aquaculture container, under the action of a booster water pump, flows through the water replenishing device and the flow transmitter in sequence, and then flows into the filter container.

[0066] It also includes an aerator, which is arranged on the inner wall of the aquaculture container and below the water surface, used to supplement the oxygen content in the water. The aerator is connected with a dissolved oxygen automatic regulator and a water level pressure transmitter, and both are then connected to an intelligent controller. Through the intelligent controller, the start and stop of the aerator are controlled and adjusted to supplement oxygen into the aquaculture container. It should be noted that the aerator, intelligent controller, dissolved oxygen automatic regulator, water level pressure transmitter, water replenishing device, flow transmitter, ozone mixing device, etc. are all directly purchased from the market.

[0067] When culturing whiteleg shrimp in inland areas without seawater, it is necessary to artificially adjust the aquaculture water body. The water temperature, pH, dissolved oxygen, total alkalinity, salinity, calcium and magnesium concentration, transparency, etc. of the water body need to be adjusted within the qualified range before releasing the shrimp fry. When taking water sources from natural river basins, mountain springs, well water or tap water, the pH values vary greatly, generally between 6 and 8. Therefore, before releasing the fry, it is necessary to adjust the water body within the allowable safety valve range. During operation after startup, it is necessary to rely on the ecological self-regulation balance (carbonate system) of the system. The ammonia nitrogen, nitrite, nitrate, hydrogen sulfide and other substances in the aquaculture water body prepared before the operation of the aquaculture system are all less than the safety valve values. When fish (shrimp) fry are released and feed is fed, the water body will be polluted by the respiration, secretion and excretion of animals, and ammonia nitrogen (NH3), nitrite (NO2 - ) and nitrate (NO3 -) and other harmful substances. To remove these harmful substances, the treatment system needs to continuously accelerate nitrification to convert the more toxic ammonia nitrogen (NH3) and nitrite (NO2 - ) into nitrate (NO2 - ) and nitrate (NO3 - ) is converted into gaseous products such as nitrogen (N2) or nitric oxide (NO) through denitrification in the system and finally released into the atmosphere.

[0068] Put whiteleg shrimp in the culture container for cultivation. After the operation of the culture system in this embodiment, the pH value, ammonia nitrogen (NH3), nitrite (NO2), nitrate (NO3 - ) of the water body in the culture container, visibility (SD) and suspended matter particles are tested every day, and the results are shown in Table 1.

[0069] Table 1

[0070]

[0071] It should be noted that the first 20 days before the system starts is the proliferation period of nitrifying bacteria (such as Nitrosomonas and Nitrobacter) (water temperature is 26 - 28 °C), and ammonia nitrogen (NH3) and nitrite (NO2 - ) are temporarily exceeded due to the immature biofilm; after about 20 - 25 days, the biofilm matures, and ammonia nitrogen is converted into nitrate (NO3 - ), and the water quality meets the standard.

[0072] It can be seen from Table 1 that the water quality of the water body treated by this system meets the standard. The filter media layer (stone nitrate, ceramsite) and the PP cotton filter bag form a stable ecological niche, and the biofilm continuously metabolizes. Nitrate is discharged from the overflow port through a small amount of water change by the automatic water replenishment device (or absorbed by plants) to control the concentration, and the water quality remains stable without maintenance and cleaning during long-term operation.

[0073] This embodiment provides a culture system with a culture pond with a diameter of 6 meters and a height of 2 meters (50m 3 water body), and the equipment cost of a single pond is about 20,000 yuan (including water pump, filter media, filter bag); cultivating whiteleg shrimp (density 20kg / m 3 ), with an annual output of 2500 kg (annual production, including loss rate). Calculated at 40 yuan / kg, the annual income is 100,000 yuan, and the investment recovery period is < 12 months.

[0074] Example 2

[0075] The difference from Example 1 is that the stone nitrate layer and the ceramsite layer respectively account for 10% and 10% of the volume of the culture container.

[0076] Example 3

[0077] It is different from Example 1 in that the stone nitre layer and the ceramsite layer respectively account for 10% and 15% of the volume of the culture container.

[0078] Example 4

[0079] It is different from Example 1 in that the stone nitre layer and the ceramsite layer respectively account for 15% and 15% of the volume of the culture container.

[0080] In summary, the recirculating aquaculture system provided by the embodiments of the present invention can block and filter water flow by arranging a filtering component at the bottom of the culture container. Larger particulate impurities such as residual baits and feces will be intercepted in the gaps between ceramsite and stone nitre, realizing preliminary physical filtration and reducing the content of impurities entering the subsequent filtration link. The impurities intercepted in the gaps between ceramsite and stone nitre, such as residual baits and feces, provide the necessary carbon source for the nitrification and denitrification activities of the treatment system. The aperture of the filter bag in the filtering container is small, which can further filter out tiny particulate impurities, plankton, bacteria and smaller organic particles in the water, making the water quality clearer.

[0081] This recirculating aquaculture system arranges the filtering component inside the culture container, which has a small floor area. Under the action of the filtering component and the filter bag, the water body in the culture container is filtered to remove impurities in the water, with low energy consumption. Only by the action of the water pump can the water cycle.

[0082] The described embodiments above are some but not all of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. A low-consumption circulating water aquaculture system based on an in-built porous tube biological filter bed, characterized in that Including, a culture container, a filtering component is arranged at the bottom inside the culture container; a filtering container, a filter bag is arranged inside the filtering container; the water outlet of the filtering component is communicated with the water inlet of the filter bag, and the water outlet of the filter bag is communicated with the top of the culture container.

2. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 1, characterized in that, The filtering component includes a water outlet pipe having a plurality of through holes and a filter material layer laid on the top of the water outlet pipe.

3. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 2, wherein The filter material layer includes a stone nitrate layer and a ceramsite layer laid in sequence from top to bottom.

4. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 2, wherein The volume of the filter material layer is 10-30% of the volume of the culture container.

5. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 3, characterized in that, The particle size of the ceramsite is 20-30 mm, the particle size of the stone nitrate is 30-50 mm, and the large porosity of the stone nitrate is 20-30%.

6. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 1, characterized in that, It further includes a booster water pump, and the booster water pump is arranged between the culture container and the filtering container.

7. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 1, characterized in that, An overflow pipe for collecting floating impurities is further arranged at the top of the culture container.

8. The low-consumption circulating water aquaculture system based on the built-in porous tube biological filter bed according to claim 1, characterized in that A feed feeding device is further arranged above the culture container.

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