A multi-stage filtering and purifying device for fish-mana coexistence system

Abstract

The utility model discloses a kind of multistage filtration purification devices for fish and vegetable symbiosis system, it is related to fish vegetable symbiosis technical field, including the sedimentation primary filtration unit, mechanical filtration unit, microbial purification unit and plant root symbiosis unit connected in turn, the sedimentation primary filtration unit is connected with mechanical filtration unit by first connecting pipe intercommunication, mechanical filtration unit is connected with microbial purification unit by second connecting pipe intercommunication, microbial purification unit is connected with plant root symbiosis unit by third connecting pipe intercommunication, and plant root symbiosis unit is connected with fish pond by backwater pipe and forms circulation system.The utility model solves the technical problem that present fish and vegetable symbiosis system purification link is single, water quality fluctuation is big, system stability is poor.

Description

Technical Field

[0001] This utility model relates to the field of aquaponics technology, specifically a multi-stage filtration and purification device for aquaponics systems. Background Technology

[0002] Aquaponics is an ecological circular agriculture model that integrates aquaculture and hydroponics. By utilizing plants to absorb nutrients such as nitrogen and phosphorus produced by fish metabolism, it achieves water purification and resource recycling. It has the advantages of water conservation, fertilizer conservation, and sustainable development, and is widely used in family agriculture, small farms, and teaching demonstration fields.

[0003] In existing technologies, aquaponics systems generally employ single or limited purification stages to treat aquaculture wastewater, such as sedimentation tanks or single-stage biological filters. While these devices are simple in structure, the lack of a multi-stage synergistic purification mechanism makes it difficult to effectively separate large particulate matter, organic pollutants, and water-soluble nitrogen and phosphorus nutrients from the water. This results in large fluctuations in water quality, easy rotting of plant roots, poor system circulation stability, and in severe cases, even fish poisoning or plant wilting, affecting the overall operational efficiency of the system.

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

[0005] The purpose of this invention is to provide a multi-stage filtration and purification device for aquaponics systems to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, this utility model provides a multi-stage filtration and purification device for an aquaponics system, comprising a sedimentation primary filtration unit, a mechanical filtration unit, a microbial purification unit, and a plant root symbiotic unit connected in sequence. The sedimentation primary filtration unit and the mechanical filtration unit are connected through a first connecting pipe, the mechanical filtration unit and the microbial purification unit are connected through a second connecting pipe, and the microbial purification unit and the plant root symbiotic unit are connected through a third connecting pipe. The plant root symbiotic unit is connected to the fish pond through a return water pipe to form a circulation system.

[0007] In one possible implementation, the sedimentation primary filtration unit includes a sedimentation tank and an inclined plate sedimentation structure. The inclined plate sedimentation structure is disposed inside the sedimentation tank to extend the water flow path and promote the settling of large particles. A drain valve is provided at the bottom of the sedimentation tank.

[0008] In one possible implementation, the mechanical filtration unit includes a sealed filter cylinder and multiple layers of filter screens disposed inside the filter cylinder, with the pore size of each layer of filter screens decreasing sequentially, for graded filtration of suspended impurities of different particle sizes, and an inspection port is provided at the top of the filter cylinder.

[0009] In one possible implementation, the microbial purification unit includes a biological tank and a multi-layer suspended filter media disposed within the tank. Nitrifying bacteria and denitrifying bacteria are attached to the filter media. An aeration pipe is provided at the bottom of the biological tank to provide oxygen to maintain the activity of the microorganisms.

[0010] In one possible implementation, the biochemical tank is equipped with a water flow buffer structure, which allows the water to remain in the tank for a certain period of time to ensure the full biological transformation of pollutants.

[0011] In one possible implementation, the plant root symbiotic unit includes a floating planting board and vegetable plants planted thereon, with the roots of the vegetable plants directly immersed in the water to absorb nutrients such as nitrogen and phosphorus from the water, and the planting board floating on the water surface of the symbiotic unit.

[0012] In one possible implementation, a water pump and a central controller are also included. The water pump is used to drive the water flow between the units, and the central controller is connected to the liquid level sensors and drain valves of each unit to automatically control the start and stop of the water pump and the drain process.

[0013] In one possible implementation, the central controller is also connected to a sensor module for detecting water quality parameters. The sensor module includes a pH sensor and a conductivity sensor, which are used to monitor the water state within the system and adjust operating parameters.

[0014] In one possible implementation, each unit structure is modularly designed, which facilitates disassembly, maintenance, and system expansion, and can be applied to scenarios such as home hydroponics, teaching demonstrations, and small-scale agricultural production.

[0015] Compared with the prior art, the beneficial effects of this utility model are: This invention relates to a multi-stage filtration and purification device for aquaponics systems. By sequentially configuring a sedimentation pre-filtration unit, a mechanical filtration unit, a microbial purification unit, and a plant root symbiotic unit, a multi-stage, collaborative water purification pathway is constructed. Through the incorporation of inclined plate sedimentation structures, multi-layered filter screens, suspended filter media, and plant root absorption structures in different units, highly efficient removal of suspended particles, organic pollutants, and nutrients such as nitrogen and phosphorus from the water can be achieved, thereby effectively improving water purification efficiency and maintaining the ecological balance of the water body within the system.

[0016] Furthermore, by incorporating water pumps, level sensors, drain valves, and a central controller, the system achieves automated operation and management, reducing the frequency of manual maintenance. The sensor module can monitor key water quality parameters such as pH and conductivity in real time, further enhancing the system's intelligence and stability. The synergistic effect of these structures and functions effectively overcomes the technical problems of existing aquaponics systems, such as poor filtration, large water quality fluctuations, and high operation and maintenance costs. It boasts advantages such as a rational structure, high purification efficiency, and a high degree of intelligent operation, making it suitable for various application scenarios, including home hydroponics, educational demonstrations, and small-scale agricultural production. 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 sedimentation and primary filtration unit of this utility model; Figure 3 This is a schematic diagram of the mechanical filtration unit structure in this utility model; Figure 4 This is a schematic diagram of the microbial purification unit structure in this utility model. Figure 5 This is a schematic diagram of the structure of the plant root symbiotic unit in this utility model. Figure 6 This is a schematic diagram of the electrical connections of the central controller of this utility model.

[0018] In the diagram: 1. Pre-filtration unit; 2. Mechanical filtration unit; 3. Microbial purification unit; 4. Plant root symbiotic unit; 5. First connecting pipe; 6. Second connecting pipe; 7. Third connecting pipe; 8. Return water pipe; 9. Sedimentation tank; 10. Inclined plate sedimentation structure; 11. Drain valve; 12. Sealed filter cylinder; 13. Multi-layer filter screen; 14. Inspection port; 15. Biological tank; 16. Suspended filter media; 17. Aeration pipe; 18. Water flow buffer structure; 19. Floating planting board; 20. Vegetable plants; 21. Water pump; 22. Central controller; 23. Liquid level sensor; 24. Sensor module; 25. pH sensor; 26. Conductivity sensor. 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 1-6This utility model provides a technical solution: a multi-stage filtration and purification device for an aquaponics system, comprising a sedimentation pre-filtration unit 1, a mechanical filtration unit 2, a microbial purification unit 3, and a plant root symbiotic unit 4. These units are sequentially connected to form a flow-through treatment structure. The sedimentation pre-filtration unit 1 is connected to the mechanical filtration unit 2 via a first connecting pipe 5; the mechanical filtration unit 2 is connected to the microbial purification unit 3 via a second connecting pipe 6; the microbial purification unit 3 is connected to the plant root symbiotic unit 4 via a third connecting pipe 7; and the plant root symbiotic unit 4 is connected to the fishpond outlet via a return water pipe 8, forming a closed-loop water circulation system. The sedimentation pre-filtration unit 1 is configured as the first treatment structure at the system's inlet, its function being to initially remove large suspended particles carried in the fishpond. Specifically, it can be constructed as a sedimentation tank with internal inclined plates, its inlet directly connected to the fishpond outlet. The tank body is made of corrosion-resistant polyethylene board to ensure that long-term contact with water does not cause structural damage. After water flows in, particles settle between the inclined plates due to gravity and low flow velocity. The first connecting pipe 5 is made of PVC-U pipe with a diameter of DN40. Its length is customized based on the actual installation distance between units. One end connects to the outlet of the sedimentation tank, and the other end connects to the inlet of the mechanical filter unit 2. It is fixed using a flange with a rubber gasket for sealing. The mechanical filter unit 2 is a closed filter cartridge with multiple layers of filter screens inside. Each layer is made of 304 stainless steel wire mesh, with the pore size decreasing sequentially from the inlet to the outlet (e.g., 2 mm, 1 mm, and 0.5 mm). These are stacked sequentially on a support inside the filter cartridge to grade and trap impurities of different particle sizes in the water. The filter cartridge has an inspection port for periodic removal and cleaning of the filter screens. The second connecting pipe 6 has the same structure as the first connecting pipe 5, connecting the outlet of the mechanical filter unit 2 to the inlet of the microbial purification unit 3. The microbial purification unit 3 is a biological tank structure, a sealed trough-type container made of corrosion-resistant polyethylene. Multiple layers of filter media are suspended inside the tank, made of polyester fiber or corrugated plastic packing, with a surface area controlled at 400 m². 2 / m 3The above provides sufficient substrate for attachment. The filter media is pre-inoculated with nitrifying and denitrifying bacteria, which can complete the biochemical reaction of ammonia nitrogen to nitrate and then nitrate back to nitrogen during water flow. An aeration system is installed at the bottom, releasing air at a uniform speed through microporous aeration pipes 17 to provide sufficient dissolved oxygen and maintain microbial activity. The third connecting pipe 7 connects the outlet of the microbial purification unit 3 to the inlet of the plant root symbiosis unit 4, with the same structure as the aforementioned connecting pipe. The plant root symbiosis unit 4 is an open planting trough covered with a floating planting board 19 made of polystyrene foam board, 30 mm thick, with multiple holes for inserting vegetable plants 20. The vegetable plants 20 are selected from varieties well-suited for hydroponics, such as water spinach, lettuce, and mint, whose roots hang directly into the water, absorbing nutrients such as nitrates and phosphates through their roots. The outlet of this planting trough connects to a return water pipe 8, also made of PVC, which connects to the inlet of the fish pond. During the dynamic operation of the entire device, the water flows through each treatment unit in sequence under the action of the water pump, completing the entire process of physical filtration, biochemical purification, and plant absorption. The purified water is returned to the fish pond, forming a closed and continuously circulating ecological filtration system. Each unit is tightly connected by pipes to ensure that the system water does not leak out and that the operation is stable and reliable.

[0021] Preferably, the sedimentation and primary filtration unit 1 includes a sedimentation tank 9 and an inclined plate sedimentation structure 10 disposed inside the sedimentation tank 9. The inclined plate sedimentation structure 10 is configured by evenly arranging several parallel inclined plates with an inclination angle of 60 degrees in the upper middle part of the sedimentation tank 9 along the water flow direction. Each inclined plate is made of polypropylene or polycarbonate plastic sheet with a thickness of 3 mm and a surface roughness controlled below 5 micrometers to enhance the adhesion and sedimentation effect of particulate matter. This structure is used to effectively extend the path length of the water flow inside the sedimentation tank 9 and force the water flow to slow down and be distributed in a laminar flow between each inclined plate, thereby promoting the sedimentation of larger suspended particulate impurities in the water to the bottom on the surface of the inclined plates. The main body of the sedimentation tank 9 is a rectangular vertical structure, made of corrosion-resistant polyethylene sheet welded together. The tank size is designed according to the treatment flow rate. When the treatment capacity is 1 ton / hour, the dimensions of the sedimentation tank 9 are set to 800 mm in length × 400 mm in width. The sedimentation tank 9 measures 1 meter x 600 mm in height. A drain valve 11 is installed on one side of the bottom of the sedimentation tank 9. The drain valve 11 is a DN25 stainless steel ball valve, connected to the lowest point of the tank and equipped with a manual knob, for periodically discharging large solid particles deposited at the bottom of the tank. During operation, water from the fish pond is introduced into the sedimentation tank 9 through the inlet. The water flows upward along the inclined plate channel at a constant flow rate. Guided by the inclined plates, the water flow forms a stable stratified flow state between each inclined plate. Suspended solids are gradually settled to the bottom of the tank under gravity and low flow rate conditions. Finally, the sediment is discharged by periodically opening the drain valve 11, and the purified supernatant flows into the next unit through the outlet. Through the reasonable design of the angle, number and arrangement density of the inclined plates, the water flow distribution and sedimentation efficiency can be precisely controlled to ensure the efficient and stable operation of the sedimentation process, thereby ensuring that the treatment efficiency of the subsequent mechanical filtration and biological purification units is not affected by front-end impurities.

[0022] Specifically, the mechanical filtration unit 2 includes a sealed filter cylinder 12 and a multi-layer filter screen 13 disposed inside the filter cylinder 12. The filter cylinder 12 adopts a cylindrical vertical structure and is made of 304 stainless steel plate with a thickness of 5 mm. It is made into a closed container by welding. A circular inspection port 14 with a diameter of 200 mm is provided on the top. The inspection port 14 is connected to a sealing cover plate through a flange. A silicone sealing ring is provided on the inside to ensure reliable sealing during the opening and closing process. The filter cartridge 12 has an inlet and an outlet at the top, with water flowing from bottom to top. The internal filter screens 13 are stacked vertically in 3 to 5 layers, each with a circular structure and edges fixed to the support frame by stainless steel retaining rings. The filter screens 13 are made of stainless steel woven mesh with different mesh sizes, ranging from 2 mm, 1 mm, 0.5 mm, 0.2 mm, and 0.1 mm from bottom to top, used to filter suspended impurities in the water according to particle size. During the dynamic operation of the system, water flows from bottom to top into the sealed filter cartridge 12 and passes through the filter screens 13 layer by layer. Particles of different sizes are sequentially trapped on different layers of filter screens, and finally, the clean water is discharged from the top outlet and enters the subsequent treatment unit. The filter screens can be cleaned or replaced periodically through the top inspection port 14 during operation to ensure stable filtration efficiency.

[0023] Specifically, the microbial purification unit 3 includes a biological tank 15 and multiple layers of suspended filter media 16 installed inside the tank. The biological tank 15 has a rectangular structure with an inner wall made of one-piece molded polyethylene material, 8 mm thick, and a smooth, corrosion-resistant inner surface. The tank size is designed according to the system flow rate; for example, when the daily water treatment capacity is 5 tons, the volume of the biological tank is set to 1.5 cubic meters. Three layers of suspended filter media 16 are installed inside the tank, each layer supported and suspended by stainless steel crossbars. The filter media material is polypropylene corrugated packing, 60 mm thick, providing more than 400 square meters of microbial attachment area per square meter. Before use, the filter media 16 undergoes pre-cultivation treatment to allow nitrifying and denitrifying bacterial communities to grow on its surface. During operation, these microorganisms complete nitrogen conversion through ammonia oxidation and nitrate reduction reactions. Three microporous aeration pipes 17, made of EPDM material, are evenly installed at the bottom of the biological tank 15. Each pipe is 800 mm long and provides uniform air distribution. Driven by a blower, they continuously supply oxygen to the water, ensuring the aerobic environment required for the nitrification process. At the same time, they promote the vertical circulation of the water, improve the contact efficiency with the filter media, and achieve efficient nitrogen removal.

[0024] Preferably, the biochemical tank 15 is further provided with a water flow buffer structure 18. This structure consists of a baffle plate positioned directly opposite the inlet. The baffle plate is made of high-density polyethylene, with a thickness of 10 mm, and is vertically installed inside the tank body, 100 mm from the tank wall. Its length covers 80% of the tank width. This structure changes the water flow path so that the water flow first impacts the baffle plate and disperses, reducing the instantaneous flow velocity. This allows the water entering the biochemical tank 15 to diffuse evenly and extend its residence time in the tank to more than 30 minutes, ensuring sufficient contact and reaction time between the water and the microorganisms in the filter media 16, thereby improving the conversion efficiency of pollutants. The buffer structure is fixed to the inner wall of the tank body with stainless steel bolts, ensuring high stability. During dynamic operation, it can effectively prevent turbulence from disturbing the microbial layer and maintain the stable progress of the biochemical reaction.

[0025] Preferably, the plant root symbiotic unit 4 includes a floating planting board 19 and vegetable plants 20 planted on it. The floating planting board 19 is made of polystyrene foam board with a thickness of 30 mm and a size of 1000 mm × 500 mm. Its buoyancy can support a weight of more than 20 kg. Planting holes with a diameter of 40 mm are evenly opened on the surface of the planting board at 100 mm intervals. A vegetable plant fixing sleeve is inserted into each hole. The sleeve is filled with soilless cultivation substrate such as perlite or coconut coir to ensure stable fixation of the plant. Shallow-rooted plants such as water spinach and lettuce are selected as vegetable plants 20. Their roots hang naturally and are directly immersed in the water of the symbiotic unit. The root surface area is large and the roots grow rapidly, which can continuously absorb residual nutrients such as nitrogen and phosphorus in the water and convert them into nutrients for plant growth, completing the plant absorption and purification process. The entire planting board 19 floats on the water surface. As the water flows slowly through the symbiotic unit, the roots are in full contact with the water, continuously recovering nutrients and releasing oxygen, which is conducive to the ecological balance of the water body in the system.

[0026] Preferably, the multi-stage filtration and purification device further includes a water pump 21 and a central controller 22. The water pump 21 is installed on the system return water pipe 8 or the main inlet water pipe. It is a DC diaphragm pump with a rated flow rate of 2 cubic meters per hour and a head of 4 meters. It is used to drive water from the fish pond through each treatment unit and back to the fish pond, forming a closed-loop water circulation path. The central controller 22 is a programmable control unit with a built-in microprocessor. It controls all liquid level sensors 23 and drain valves 11 through wired connections. The liquid level sensors 23 are installed at the liquid level control points of the sedimentation tank 9, filter cartridge 12, biological tank 15 and symbiotic unit 4. The sensors are capacitive water level probes. When the liquid level reaches the set upper or lower limit, a signal is sent to the central controller 22. The controller controls the start and stop of the water pump 21 and the automatic opening and closing of each drain valve 11 according to the preset logic, realizing automatic water level management and sediment discharge operation of each unit. The system achieves automated operation and reduces manual intervention.

[0027] Preferably, the central controller 22 is further connected to a sensor module 24 for detecting water quality parameters. The sensor module 24 includes a pH sensor 25 and a conductivity sensor 26. The pH sensor 25 is a glass electrode type with a detection range of 0-14, and the conductivity sensor 26 is an electrode type with a measurement range of 0-2000 μS / cm. Both are connected to the data acquisition module of the controller 22 through a BNC interface. The sensor module 24 is installed in the water channel between the microbial purification unit 3 and the plant root symbiotic unit 4 to monitor the pH and salinity of the treated water in real time. The central controller 22 periodically collects and analyzes the sensor data through built-in software, and adjusts the pump speed, controls the aeration intensity, or prompts the replacement of filter media according to preset parameters to ensure that the system is in the optimal operating state for a long time and effectively avoids the impact of water quality deterioration on fish or plants.

[0028] Preferably, each unit adopts a modular design. The sedimentation and primary filtration unit 1, mechanical filtration unit 2, microbial purification unit 3, and plant root symbiosis unit 4 are each set as independent box structures. Each unit is equipped with a stainless steel bracket and non-slip feet at the bottom, which facilitates individual disassembly and maintenance. The connecting pipes 5, 6, 7 and return water pipe 8 use quick-connect couplings, which can be quickly connected and disassembled without special tools during installation. All electrical control components, such as the water pump 21, central controller 22, and sensor module 24, are installed in independent control boxes and connected to each unit through plug-in interfaces. This modular structure not only enables rapid response to system maintenance, but also allows for flexible expansion or reduction of the number of treatment units according to home hydroponics, teaching demonstrations, or small-scale agricultural applications, ensuring that the device can adapt to different scale requirements. At the same time, maintenance operations are more intuitive and safe, and the system's adaptability and practicality are greatly improved.

[0029] This multi-stage filtration and purification device is based on the cyclical ecological principle of aquaponics. It employs a multi-stage series structure, integrating four functional modules—sedimentation and pre-filtration, mechanical filtration, biochemical purification, and plant absorption—into a closed-loop water treatment system. The system operates by an external water pump driving continuous water flow. The water undergoes different types of purification processes in each treatment unit, ultimately achieving stable water quality and enabling recycling.

[0030] First, water from the fishpond containing suspended impurities and organic waste enters the sedimentation and primary filtration unit 1 under the drive of water pump 21. This unit has an inclined plate sedimentation structure 10, which extends the water flow path and reduces the water flow velocity, causing denser particulate impurities in the water to settle to the bottom under gravity. The sediment is periodically discharged through the drain valve 11, achieving preliminary physical separation. The pre-clarified water then enters the mechanical filtration unit 2 through the first connecting pipe 5. The water flows in from the bottom of the filter cylinder 12 and passes through multiple layers of filter screens 13, with the pore size decreasing progressively. Suspended particles of different sizes are trapped on different layers of filter screens, achieving high-precision graded solid-liquid separation. The mechanically filtered water flows out from the top outlet and enters the microbial purification unit 3 through the second connecting pipe 6.

[0031] In the microbial purification unit 3, the water first passes through the water flow buffer structure 18 for diffusion and deceleration, and then enters the biological tank 15 equipped with multi-layer suspended filter media 16. The nitrifying bacteria attached to the filter media oxidize the ammonia nitrogen (NH3-N) in the water into nitrite (NO2). - ) and nitrates (NO3) - The nitrates are then reduced to nitrogen (N2) by denitrifying bacteria, thus achieving the recycling and removal of nitrogen in the water. An aeration pipe 17 is installed at the bottom of the tank to continuously supply oxygen, ensuring an aerobic environment for the nitrification process. This also maintains vertical circulation of the water within the tank, improving contact efficiency with microorganisms and promoting a thorough reaction.

[0032] The water, purified by microorganisms, is introduced into the plant root symbiosis unit 4 via the third connecting pipe 7. The water flows beneath the floating planting board 19, where it comes into direct contact with the roots of the vegetable plants 20 planted on the board. The vegetable plant roots absorb residual nitrates, phosphates, and other soluble nutrients in the water, converting them into growth substances for the plants, while simultaneously releasing oxygen to improve the aquatic environment. Finally, the purified water returns to the fishpond via the return pipe 8, forming a complete water cycle.

[0033] During this process, the central controller 22 receives signals from the level sensor 23 and automatically controls the start and stop of the water pump 21 and the opening timing of the drain valve 11, thereby automating the level management and drain process. The controller is also connected to the water quality sensor module 24 to collect parameters such as pH value and conductivity in real time. If the system operation deviates from the preset value, the controller can issue adjustment commands to optimize the operating status and ensure long-term system stability.

[0034] Overall, the device relies on the principles of fluid dynamics, water treatment engineering, and ecological agriculture to achieve a triple synergistic purification of "physical + biochemical + plant". Through modular structure integration and closed-loop operation logic, it effectively improves water purification efficiency, system stability, and ecological compatibility, providing a reliable water quality guarantee and engineering implementation path for aquaponics.

[0035] 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 multi-stage filtration and purification device for an aquaponics system, characterized in that, The system includes a sedimentation and primary filtration unit (1), a mechanical filtration unit (2), a microbial purification unit (3), and a plant root symbiotic unit (4) connected in sequence. The sedimentation and primary filtration unit (1) and the mechanical filtration unit (2) are connected through a first connecting pipe (5). The mechanical filtration unit (2) and the microbial purification unit (3) are connected through a second connecting pipe (6). The microbial purification unit (3) and the plant root symbiotic unit (4) are connected through a third connecting pipe (7). The plant root symbiotic unit (4) is connected to the fish pond through a return water pipe (8) to form a circulation system.

2. The multi-stage filtration and purification device according to claim 1, characterized in that, The sedimentation and primary filtration unit (1) includes a sedimentation tank (9) and an inclined plate sedimentation structure (10). The inclined plate sedimentation structure (10) is located inside the sedimentation tank (9) to extend the water flow path and promote the settling of large particles. The sedimentation tank (9) is equipped with a drain valve (11).

3. The multi-stage filtration and purification device according to claim 1, characterized in that, The mechanical filtration unit (2) includes a sealed filter cylinder (12) and a multi-layer filter screen (13) disposed inside the filter cylinder (12). The pore size of each layer of filter screen (13) decreases sequentially, and is used for graded filtration of suspended impurities of different particle sizes. The top of the filter cylinder (12) is provided with an inspection port (14).

4. The multi-stage filtration and purification device according to claim 1, characterized in that, The microbial purification unit (3) includes a biochemical tank (15) and a multi-layer suspended filter media (16) installed in the tank. Nitrifying bacteria and denitrifying bacteria are attached to the filter media (16). An aeration pipe (17) is provided at the bottom of the biochemical tank (15) to provide oxygen to maintain the activity of microorganisms.

5. The multi-stage filtration and purification device according to claim 4, characterized in that, The biochemical pool (15) is equipped with a water flow buffer structure (18) to allow the water to remain in the pool for a certain period of time in order to ensure the full biological transformation of pollutants.

6. The multi-stage filtration and purification device according to claim 1, characterized in that, The plant root symbiotic unit (4) includes a floating planting board (19) and vegetable plants (20) planted on it. The roots of the vegetable plants (20) are directly immersed in the water to absorb nitrogen and phosphorus nutrients in the water. The planting board (19) floats on the water surface of the symbiotic unit.

7. The multi-stage filtration and purification device according to claim 1, characterized in that, It also includes a water pump (21) and a central controller (22). The water pump (21) is used to drive the water flow between the units, and the central controller (22) is connected to the liquid level sensor (23) and the drain valve (11) of each unit to automatically control the start and stop of the water pump (21) and the drain process.

8. The multi-stage filtration and purification device according to claim 7, characterized in that, The central controller (22) is also connected to a sensor module (24) for detecting water quality parameters. The sensor module (24) includes a pH sensor (25) and a conductivity sensor (26) for monitoring the water state in the system and adjusting the operating parameters.

9. The multi-stage filtration and purification device according to any one of claims 1 to 8, characterized in that, Each unit is modularly designed, making it easy to disassemble, maintain, and expand the system. It can be applied to home hydroponics, teaching demonstrations, and small-scale agricultural production scenarios.

Images