A high-efficiency nutrient circulation filtering device for a fish-mana symbiotic system

Abstract

The utility model relates to fish and vegetable symbiosis technical field discloses a kind of efficient nutrient circulation filter devices for fish and vegetable symbiosis system, including shell, water inlet module, multistage filtration module, water collection and backflow module and control module;Shell is modular structure, is equipped with water inlet end and water outlet end;Water inlet module includes the water pipe connected fish pond and the grid filter for filtering large particle impurities;Multistage filtration module includes micro-bubble aerator, biological filter layer, fine mesh filter layer and adsorption layer in turn, setting in micro-bubble aerator spouting mechanism to promote water body dissolved oxygen content, biological filter layer is filled with biological carrier for ammonia nitrogen degradation, fine mesh filter layer is used for intercepting suspended particles, and adsorption layer fills activated carbon for removing residual harmful substances;Water collection and backflow module includes siphon, booster pump and the water outlet pipe connected vegetable root area.Solved the technical problem that water quality purification efficiency is low in fish and vegetable symbiosis system, nutrient conversion ability is poor and maintenance cost is high.

Description

Technical Field

[0001] This utility model relates to the field of aquaponics technology, specifically to a high-efficiency nutrient circulation and filtration device for aquaponics systems. Background Technology

[0002] In aquaponics systems, nutrients such as ammonia nitrogen from fish excrement provide natural fertilizer for vegetable cultivation through water circulation. However, the cleanliness of the water and the efficiency of nutrient conversion directly affect the overall ecological balance of the system and the yield of vegetables. Therefore, setting up effective water filtration and nutrient circulation devices is a key technical aspect of such systems.

[0003] Existing aquaponics water treatment systems generally suffer from the following shortcomings: First, the filtration devices have a simple structure, typically employing sedimentation tanks or sand filters, which are inefficient at removing large particles and suspended particles produced by fish metabolism, easily causing water turbidity. Second, they lack effective biological filtration modules, making it difficult for harmful substances such as ammonia nitrogen to be stably degraded by nitrifying bacteria and other microorganisms, thus affecting water quality safety and the health of vegetable roots. Third, most existing systems lack integrated automated control mechanisms; backwashing of the filtration devices, operational status monitoring, and water quality parameter monitoring rely on manual operation, resulting in high system maintenance costs, slow response times, and difficulty in achieving long-term stable operation. Furthermore, some filtration devices lack modular structure and tiered treatment design, failing to perform fine-grained filtration of pollutants of different particle sizes, and are also difficult to adapt to the flexible deployment and expansion of aquaponics systems of different sizes.

[0004] In view of the above, this application is hereby submitted. Utility Model Content

[0005] The purpose of this invention is to provide a high-efficiency nutrient circulation and filtration device for aquaponics systems, in order to solve the problems mentioned in the background art.

[0006] To address the aforementioned technical problems, this utility model provides a nutrient circulation filtration device for an aquaponics system, comprising a shell, a water inlet module, a multi-stage filtration module, a water collection and return module, and a control module. The shell is a modular structure with an inlet and an outlet. The water inlet module includes a water guide pipe and a bar filter; the water guide pipe connects to the fishpond, and the bar filter filters large particles. The multi-stage filtration module is sequentially connected downstream of the bar filter and includes a microbubble aerator, a biological filter layer, a fine mesh filter layer, and an adsorption layer. The microbubble aerator contains a jetting mechanism to generate microbubbles and increase dissolved oxygen levels in the water. The biological filter layer is filled with biological carriers for microbial attachment and ammonia nitrogen degradation. The fine mesh filter layer further traps suspended particles. The adsorption layer is filled with activated carbon to remove residual harmful substances. The water collection and return module includes a siphon tank, a lift pump, and an outlet pipe. The siphon tank is located downstream of the adsorption layer and connected to the lift pump, which is connected to the outlet pipe, which connects to the root area of ​​the vegetables.

[0007] In one possible implementation, the microbubble aeration cylinder is equipped with an integrated spraying mechanism, which includes: a swirling nozzle located at the bottom of the aeration cylinder, the swirling nozzle comprising a spiral water inlet channel and an axial water outlet, the spiral water inlet channel being connected to the water inlet module to form a rotating water flow; and an annular air inlet chamber located around the swirling nozzle, the air inlet chamber being connected to the axial water outlet through multiple radial air inlets to introduce gas to form microbubbles as the water flow passes through. By fully mixing the water flow and gas through the spraying mechanism, dissolved oxygen efficiency can be improved and the aggregation and sedimentation of suspended particles can be promoted.

[0008] In one possible implementation, the biological carrier in the biofiltration layer is a structurally shaped filler made of porous honeycomb ceramic. The honeycomb ceramic unit is a porous cubic structure with transverse and longitudinal through holes on the outside, forming staggered channels. Multiple honeycomb ceramic units are stacked and filled inside the filter chamber in the biofiltration layer. The surface of the biological carrier is hydrophilically treated to provide a microbial attachment interface, thereby enhancing the growth stability of nitrifying bacteria and the ammonia nitrogen degradation efficiency.

[0009] In one possible implementation, the fine mesh filter layer includes a housing, a pull-out filter assembly, and a flushing pipe. The housing is a sealed filter box with guide rails. The filter assembly includes a frame and a tensioned mesh. Slider blocks are provided on both sides of the frame, and the sliders cooperate with the guide rails to achieve slidable installation of the filter assembly. The tensioned mesh is fixed to the frame, and the mesh aperture is 50 micrometers to 200 micrometers for intercepting suspended particles. The flushing pipe is fixedly located on one side of the housing and has a nozzle orifice facing the filter assembly to facilitate periodic water flushing, reduce clogging, and extend the service life.

[0010] In one possible implementation, the adsorption layer is covered with a filter mesh to prevent particulate matter from leaking out and to extend the replacement cycle of the adsorption medium.

[0011] In one possible implementation, the backwash valve in the control module is located on the connecting pipeline between the microbubble aerator and the biofilter layer, and is linked to the controller signal to periodically discharge sediment.

[0012] In one possible implementation, the booster pump is a low-head type and is connected to a water level sensor to automatically start and stop by detecting changes in the water level in the planting trough.

[0013] In one possible implementation, the outer wall of the shell is provided with a heat insulation layer and a light-shielding layer to improve the environmental adaptability of the device and ensure stable growth conditions for internal microorganisms.

[0014] In one possible implementation, the control module includes a flow sensor located at the outlet of the inlet module, a pH sensor located between the biological filter layer and the fine mesh filter layer in the multi-stage filtration module, an ammonia nitrogen sensor located at the outlet of the adsorption layer, and a backwash valve installed on the connecting pipeline between the microbubble aerator and the biological filter layer; each sensor and the backwash valve are electrically connected to the controller to realize real-time monitoring of the operating status of the filtration system and automatic flushing control of the filter components.

[0015] Compared with the prior art, the beneficial effects of this utility model are: This utility model discloses a nutrient circulation filtration device for aquaponics systems. Structurally, it integrates multiple functional units such as water inlet, filtration, water collection and recirculation, and control through a modular shell, achieving efficient water treatment within a limited space. The multi-stage filtration module sequentially comprises a microbubble aerator, a biological filter layer, a fine mesh filter layer, and an adsorption layer. Each layer has a clearly defined function, synergistically enhancing filtration efficiency. The integrated jet mechanism within the microbubble aerator enhances water-air mixing, increasing dissolved oxygen levels and creating favorable conditions for subsequent biological treatment. The biological filter layer uses structurally fixed honeycomb ceramics as a biological carrier, facilitating stable microbial attachment and ammonia nitrogen degradation. The fine mesh filter layer and adsorption layer further complete solid-liquid separation and pollutant adsorption, effectively improving the purification level of the effluent.

[0016] In addition, the device is equipped with a water collection and return module, which operates in conjunction with a low-lift pump via a siphon tank to return filtered water to the planting trough area, completing the nutrient circulation path. The external control module integrates flow, pH, and ammonia nitrogen sensors and is linked to the backwash valve, enabling the device to perform operational monitoring and automatic maintenance. The overall structure is compact and rationally designed, suitable for various small to medium-sized aquaponics systems, significantly improving the purification efficiency, operational stability, and ease of maintenance of the filtration device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the microbubble aeration cylinder structure of this utility model; Figure 3 This is a schematic diagram of the adsorption layer in this utility model; Figure 4 This is a schematic diagram of the structure of the fine mesh filter layer in this utility model; Figure 5 This is a schematic diagram of the biological filtration layer in this utility model; Figure 6 This is a logic block diagram of the control module in this utility model.

[0018] In the diagram: 1. Shell; 2. Water inlet module; 3. Multi-stage filtration module; 4. Water collection and return module; 5. Control module; 6. Water outlet pipe; 7. Water guide pipe; 8. Bar screen filter; 9. Microbubble aerator; 10. Spray mechanism; 11. Swirl nozzle; 12. Spiral water inlet channel; 13. Axial water outlet; 14. Annular air inlet chamber; 15. Radial air inlet hole; 16. Biological filtration layer; 17. Biological carrier; 18. Fine mesh filtration layer; 19. Filter screen assembly; 20. Tensioned mesh; 21. Flushing pipeline; 22. Nozzle outlet; 23. Adsorption layer; 24. Activated carbon; 25. Filter mesh; 26. Siphon tank; 27. Lift pump; 28. Water level sensor; 29. ​​Flow sensor; 30. pH sensor; 31. Ammonia nitrogen sensor; 32. Backwash valve; 33. Controller; 34. Heat insulation layer; 35. Light-shielding layer. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figures 1-5This utility model provides a technical solution: a nutrient circulation filtration device for an aquaponics system includes a shell 1, a water inlet module 2, a multi-stage filtration module 3, a water collection and return module 4, and a control module 5. The shell 1 has a modular structure and is provided with an inlet end and an outlet end. The water inlet module 2 includes a water guide pipe 7 and a bar filter 8. The water guide pipe 7 is connected to the fish pond, and the bar filter 8 is used to intercept large particulate impurities. The multi-stage filtration module 3 is arranged downstream of the bar filter 8 and includes a microbubble aerator 9, a biological filter layer 16, a fine mesh filter layer 18, and an adsorption layer 23. The microbubble aerator 9 is provided with a spray mechanism 10 to form microbubbles and increase dissolved oxygen. The biological filter layer 16 is filled with a biological carrier 17 for microbial attachment and ammonia nitrogen degradation. The fine mesh filter layer 18... The filter layer 18 is used to further trap suspended particles; the adsorption layer 23 is filled with activated carbon 24 to remove residual harmful substances; the water collection and return module 4 includes a siphon tank 26 located downstream of the adsorption layer 23, a lift pump 27 connected to the siphon tank 26, and an outlet pipe 6 connected to the lift pump 27. The outlet pipe 6 is connected to the root area of ​​the vegetables. The control module 5 is used to coordinate the operation of the device. The determination and implementation process of each technical feature and structural feature is as follows: the shell 1 adopts a detachable segmented modular structure. Several positioning steps and sealing grooves are set on its inner wall along the water flow direction. The outer edge of each functional unit is set with a corresponding positioning shoulder and sealing ring. During assembly, it is pushed in section by section in the order of "water inlet → aeration → biological → fine screen → adsorption → siphon" and the end face of the shell 1 is used as the assembly point. The reference form a straight flow channel. The dimensions of the shell 1 are determined based on the designed processing flow rate and allowable flow velocity. The inner diameter of the guide pipe 7 is determined based on the fishpond outlet flow rate and allowable flow velocity. The length of the guide pipe 7 is determined based on the center distance between the fishpond outlet and the inlet of the shell 1. The inlet of the guide pipe 7 is sealed to the fishpond outlet via a rigid flange or a straight-insertion sealing sleeve. The outlet end is machined to the position of the inner stop surface of the shell 1 to ensure axial positioning. The bar spacing of the bar filter 8 is determined based on the minimum target particle size to be intercepted and is smaller than that particle size. The effective water passage area of ​​the bar is calculated based on the designed flow rate and allowable water passage velocity. The bar frame is pressed tightly against the positioning steps of the shell 1 to prevent bypass. The cylinder volume of the microbubble aerator 9 is determined based on the required hydraulic retention time and the designed flow rate. The spray mechanism 10 is fixed to the center of the bottom of the aeration cylinder 9 by means of threads or flanges. Its axial outflow direction is consistent with the cylinder axis. The nozzle diameter and the length of the contraction section of the spray mechanism 10 are determined according to the requirements of forming high-speed shear mixing and generating micron-sized bubbles. The effective thickness of the biological filter layer 16 is determined according to the balance of the influent ammonia nitrogen concentration, the specific surface area of ​​the packing and the target removal rate. The biological carrier 17 is evenly distributed from top to bottom to the designed thickness and locked with pressure strips. The biological carrier 17 is tightly attached to the inner wall of the shell 1 to eliminate bypass flow. The mesh aperture of the fine mesh filter layer 18 is determined according to the characteristic particle size of the suspended particles to be intercepted and is not larger than the particle size. The effective area of ​​the mesh surface is determined according to the design flow rate and the allowable surface velocity. The filter screen frame slides into the guide groove in the shell and is pressed by the limiting block.The filling height of activated carbon 24 in adsorption layer 23 is determined according to the required empty bed contact time. After filling, it is leveled to the design height using a leveling plate and shaped with a pressing mesh plate. The side of adsorption layer 23 is tightly attached to the inner wall of shell 1. The bottom elevation of siphon tank 26 is lower than the outlet elevation of adsorption layer 23 to ensure gravity flow. The outlet of siphon tank 26 is connected to the inlet of lift pump 27 through a rigid short pipe. The rated head of lift pump 27 is determined according to the height difference between the liquid surface of siphon tank and the root area of ​​vegetables and the friction loss. The rated flow rate of lift pump 27 is consistent with the design processing flow rate. The inner diameter of outlet pipe 6 is determined according to the design flow rate and allowable flow velocity. The end of outlet pipe 6 is fixed to the root area of ​​vegetables and positioned facing the root group. Control module 5 provides on / off and sequential control for the above components. Its control output is directly connected to the motor input of lift pump 27 to realize start and stop. Control module 5 is installed on the outer wall of shell 1 for easy wiring and maintenance. When the system starts operating, the fishpond water enters the device through the water guide pipe 7 under the command of the control module 5. First, large particles are intercepted at the bar screen filter 8, where they settle due to gravity and accumulate under the influence of water flow in the front area. After a stable flow pattern is established downstream, the water flows into the microbubble aerator 9. The jetting mechanism 10 generates a high-speed water jet that draws in air within the aerator, forming numerous microbubbles. As these microbubbles rise, they continuously contact the water and release oxygen, gradually increasing the dissolved oxygen concentration. The water effluent from the top of the aerator, carrying oxygenated water, enters the biological filter layer 16. Within the biological filter layer 16, the water flows through the porous channels of the biological carrier 17. Microorganisms attach to the carrier surface, forming a biofilm. Ammonia nitrogen is oxidized sequentially to nitrite and nitrate within the biofilm, gradually reducing the ammonia nitrogen concentration. The effluent then enters the fine mesh filter layer 18. Within the fine mesh filter layer 18, the water flows through the filter screen, and suspended particles are screened and retained, gradually forming a thin filter cake on the screen surface. The retention efficiency increases over time, while the resistance gradually increases within the design range. The water, after being filtered through a fine mesh, enters the adsorption layer 23. Activated carbon 24 physically and chemically adsorbs residual harmful dissolved substances in the water on its surface and within its pores. The adsorption front gradually advances to the end of the layer, maintaining a stable purification effect in the effluent throughout the designed operating cycle. The treated purified water enters the siphon tank 26 and collects under gravity. After the control module 5 sends a pump start signal, the lift pump 27 delivers the water to the outlet pipe 6 and evenly returns it to the vegetable root area. After the roots absorb nutrients, the remaining water returns to the fish pond, thus forming a dynamic cycle of fish pond → filtration → vegetables → fish pond. By sequentially completing five stages of treatment—large particle removal, oxygenation, biodegradation, particle filtration, and adsorption purification—gradual purification from coarse to fine, from particles to dissolved substances is ensured. Microbubble aeration increases dissolved oxygen and enhances the stability of the biological layer. The biological layer degrades ammonia nitrogen, reducing the toxicity of the fish pond. The fine mesh layer and adsorption layer achieve deep purification. The siphon tank and lift pump ensure a stable water flow back to the vegetable root area. The modular structure of the shell 1 facilitates maintenance and expansion.

[0021] Preferably, the microbubble aerator 9 is equipped with an integrated spray mechanism 10. The spray mechanism 10 includes a swirling nozzle 11 installed at the bottom of the aerator 9. The swirling nozzle 11 has a spiral water inlet channel 12 and an axial water outlet 13. The spiral water inlet channel 12 is connected to the water inlet module 2 and can convert the incoming water flow into a swirling flow. An annular air inlet chamber 14 is provided around the swirling nozzle 11. The annular air inlet chamber 14 is connected to the axial water outlet 13 through multiple radial air inlet holes 15. When the swirling water flow passes through at high speed, a negative pressure is generated, and air is drawn into the water through the air inlet chamber 14 and the air inlet holes 15. The flow of water creates microbubbles. During dynamic operation, the water in the fishpond enters the spiral channel and forms a rotating flow. When the rotating flow is ejected through the axial outlet, a negative pressure is created near the nozzle, drawing air in from the annular air inlet chamber 14. The air and water flow mix at high speed, and the water flow is dispersed into a large number of microbubbles under shear force. The microbubbles rise and diffuse evenly, causing the dissolved oxygen in the water to increase rapidly. At the same time, suspended particles are aggregated and settled due to the upward stirring of the microbubbles. Through the synergistic effect of the swirling nozzle 11 and the annular air inlet chamber 14, the air and water are fully mixed, the dissolved oxygen efficiency is significantly improved, and the structure is compact and stable.

[0022] Preferably, the biological carrier 17 filled in the biological filter layer 16 adopts a structurally defined honeycomb ceramic unit. The honeycomb ceramic has a porous cubic structure with transverse and longitudinal through holes processed on the outer surface. The through holes are interconnected to form multi-dimensional channels, allowing water to fully contact the carrier surface when flowing between the channels. Multiple honeycomb ceramic units are arranged in a stacked manner and filled inside the filter chamber. The stacking order ensures that the through holes are aligned to form a continuous flow channel. The carrier surface is hydrophilic to enhance its wettability, which is conducive to the rapid attachment and growth of microorganisms. The fish pond water flows through the honeycomb ceramic from top to bottom. Dissolved oxygen provides sufficient conditions for nitrifying bacteria. Ammonia nitrogen is gradually oxidized to nitrite under the action of microorganisms, and then further oxidized to nitrate, so that the ammonia nitrogen concentration in the water gradually decreases.

[0023] Preferably, the fine mesh filter layer 18 includes a housing, a pull-out filter assembly 19, and a flushing pipe 21. The housing is a sealed filter box with guide rails. The filter assembly 19 includes a frame and a tension mesh 20. Slider blocks are provided on both sides of the frame, and the sliders cooperate with the guide rails of the housing to achieve slidable installation. The tension mesh 20 is fixed on the frame, with a pore size of 50 to 200 micrometers. Suspended particles are trapped when water flows through it. The flushing pipe 21 is fixed on one side of the housing, with the nozzle 22 facing the filter assembly 19. During backwashing, high-pressure water flow washes the filter surface to remove deposits. During operation, water continuously flows through the filter assembly 19, and suspended matter gradually accumulates on the mesh surface to form a filter cake. The flow resistance gradually increases. When the set pressure difference value is reached, the control module 5 opens the flushing pipe 21, and the nozzle 22 sprays water to impact the filter. The filter cake is peeled off and discharged with the backwash water, and the filter returns to permeability. The pull-out filter assembly 19 facilitates maintenance and replacement, and the flushing pipe 21 achieves online self-cleaning, reducing the frequency of manual maintenance.

[0024] Preferably, the adsorption layer 23 is covered with a filter mesh 25. The mesh 25 covers the outer wall of the adsorption layer, forming a physical barrier to prevent activated carbon 24 particles from leaking out with the water flow. The pore size of the mesh 25 is smaller than the minimum particle diameter of activated carbon 24, thereby ensuring the stable operation of the adsorption layer. When water flows through the adsorption layer 23, the mesh 25 blocks the leakage of particles, keeps the adsorption bed intact, and extends the service life of the adsorption layer. The mesh 25 avoids water pollution and adsorption capacity reduction caused by activated carbon loss, and extends the media replacement cycle.

[0025] Preferably, the backwash valve 32 in the control module 5 is installed on the connecting pipe between the microbubble aerator 9 and the biological filter layer 16, and is linked with the controller 33 by signal. It is opened periodically to discharge sediment in the pipe and aerator. During dynamic operation, when the controller 33 receives a differential pressure sensor or a timing signal, the backwash valve 32 opens, and the sediment in the aerator 9 and the connecting pipe is quickly discharged with the water flow. Then the valve 32 closes, restoring normal filtration. The backwash valve 32 can effectively prevent the aerator 9 and the inlet of the biological filter layer 16 from becoming blocked, and maintain smooth water flow.

[0026] Preferably, the lift pump 27 is a low-head type and is electrically connected to the water level sensor 28. The water level sensor 28 detects changes in the liquid level in the planting trough and controls the lift pump 27 to start and stop automatically. During dynamic operation, when the water level in the planting trough is lower than the set lower limit, the sensor 28 outputs a signal to the control module 5. The control module 5 drives the lift pump 27 to start supplying water. When the water level rises to the upper limit, the sensor 28 feeds back a signal, and the control module 5 shuts down the lift pump 27 to prevent overflow. The lift pump 27 operates under low-head conditions, which is energy-saving and efficient. The water level sensor 28 achieves automatic control, ensuring stable operation of the system.

[0027] Preferably, the outer wall of the shell 1 is provided with a heat insulation layer 34 and a light-shielding layer 35. The heat insulation layer 34 is made of foamed polyurethane or other low thermal conductivity material to cover the outer surface of the shell. The light-shielding layer 35 is made of black film or coating to cover the outside of the heat insulation layer 34 to isolate external light and heat. The heat insulation layer 34 effectively reduces the impact of external temperature changes on the water inside the shell, and the light-shielding layer 35 prevents direct sunlight and avoids algae growth. The double protection improves the environmental adaptability of the device and ensures a stable growth environment for internal microorganisms.

[0028] Preferably, the control module 5 includes a flow sensor 29 installed at the outlet of the inlet module 2, a pH sensor 30 installed between the biological filter layer 16 and the fine mesh filter layer 18, an ammonia nitrogen sensor 31 installed at the outlet of the adsorption layer 23, and a backwash valve 32 installed on the connecting pipeline between the aeration tank 9 and the biological filter layer 16; each sensor and the backwash valve 32 are electrically connected to the controller 33; the flow sensor 29 monitors the inlet water volume in real time and feeds it back to the controller 33, the pH sensor 30 detects the acidity and alkalinity of the water to ensure suitable microbial growth, and the ammonia nitrogen sensor 31 monitors whether the purified water quality meets the standards. If the detected value is abnormal, the controller 33 sends a signal to control the backwash valve 32 to open or adjust the operating mode to ensure system stability; the real-time monitoring of the operating status is achieved through multi-sensor linkage, and the controller 33 automatically adjusts according to the signals, improving the intelligence and stability of the device.

[0029] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A high-efficiency nutrient circulation filtration device for aquaponics systems, comprising a shell (1), a water inlet module (2), a multi-stage filtration module (3), a water collection and return module (4), and a control module (5), characterized in that: The shell (1) is a modular structure with an inlet and an outlet. The inlet module (2) includes a water guide pipe (7) and a bar screen filter (8). The water guide pipe (7) is connected to the fish pond, and the bar screen filter (8) is used to filter large particulate impurities. The multi-stage filtration module (3) is connected downstream of the bar screen filter (8) and includes a microbubble aerator (9), a biological filter layer (16), a fine mesh filter layer (18), and an adsorption layer (23). The microbubble aerator (9) is equipped with a spray mechanism (10) to form microbubbles and increase the dissolved oxygen content of the water. The biological filter layer (16) is filled with a biological carrier (17) for microbial attachment and ammonia nitrogen degradation. The fine mesh filter layer (18) is used to further intercept suspended particles. The adsorption layer (23) is filled with activated carbon (24) to remove residual harmful substances. The water collection and return module (4) includes a siphon tank (26), a lift pump (27) and a water outlet pipe (6). The siphon tank (26) is located downstream of the adsorption layer (23) and connected to the lift pump (27). The lift pump (27) is connected to the water outlet pipe (6), which is connected to the root area of ​​the vegetables.

2. The nutrient circulation filtration device according to claim 1, characterized in that, The microbubble aeration cylinder (9) is equipped with an integrated spray mechanism (10). The spray mechanism (10) includes: a swirling nozzle (11) located at the bottom of the aeration cylinder (9). The swirling nozzle (11) includes a spiral water inlet channel (12) and an axial water outlet (13). The spiral water inlet channel (12) is connected to the water inlet module (2) to form a rotating water flow. An annular air inlet chamber (14) is located around the swirling nozzle (11). The air inlet chamber (14) is connected to the axial water outlet (13) through multiple radial air inlet holes (15) to introduce gas to form microbubbles when the water flows through. By fully mixing the water flow and gas through the spray mechanism (10), the dissolved oxygen efficiency can be improved and the aggregation and sedimentation of suspended particles can be promoted.

3. The nutrient circulation filtration device according to claim 1, characterized in that, The biological carrier (17) in the biological filter layer (16) is a structurally shaped filler made of porous honeycomb ceramic. The honeycomb ceramic unit is a porous cubic structure with transverse and longitudinal through holes on the outside, forming an interlaced channel. Multiple honeycomb ceramic units are stacked and filled inside the filter chamber in the biological filter layer (16). The surface of the biological carrier (17) is hydrophilically treated to provide a microbial attachment interface and enhance the growth stability of nitrifying bacteria and the ammonia nitrogen degradation efficiency.

4. The nutrient circulation filtration device according to claim 1, characterized in that, The fine mesh filter layer (18) includes a shell, a pull-out filter assembly (19), and a flushing pipe (21). The shell is a sealed filter box with a guide rail. The filter assembly (19) includes a frame and a tension mesh (20). The frame has sliders on both sides, and the sliders cooperate with the guide rail to achieve the sliding installation of the filter assembly (19). The tension mesh (20) is fixed on the frame and has a mesh size of 50 micrometers to 200 micrometers, which is used to intercept suspended particles. The flushing pipe (21) is fixedly installed on one side of the housing and is provided with a nozzle (22). The nozzle (22) faces the filter assembly (19) to facilitate regular water flushing, reduce clogging and extend the service life.

5. The nutrient circulation filtration device according to claim 1, characterized in that, The adsorption layer (23) is covered with a filter cloth (25) to prevent particulate matter from leaking out and to extend the replacement cycle of the adsorption medium.

6. The nutrient circulation filtration device according to claim 1, characterized in that, The backwash valve (32) in the control module (5) is located on the connecting pipeline between the microbubble aeration cylinder (9) and the biofiltration layer (16) and is linked with the controller (33) to periodically discharge sediment.

7. The nutrient circulation filtration device according to claim 1, characterized in that, The lift pump (27) is a low-head type and is connected to the water level sensor (28), which can automatically start and stop by detecting changes in the water level of the planting trough.

8. The nutrient circulation filtration device according to claim 1, characterized in that, The outer wall of the shell (1) is provided with a heat insulation layer (34) and a light-shielding layer (35) to improve the environmental adaptability of the device and ensure stable growth conditions for internal microorganisms.

9. The nutrient circulation filtration device according to claim 1, characterized in that, The control module (5) includes a flow sensor (29) installed at the outlet of the inlet module (2), a pH sensor (30) installed between the biological filter layer (16) and the fine mesh filter layer (18) in the multi-stage filtration module (3), an ammonia nitrogen sensor (31) installed at the outlet of the adsorption layer (23), and a backwash valve (32) installed on the connecting pipeline between the microbubble aerator (9) and the biological filter layer (16). Each sensor and the backwash valve (32) are electrically connected to the controller (33) to realize real-time monitoring of the operating status of the filtration system and automatic flushing control of the filtration components.

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