A gradient dissolved oxygen guided multi-filler synergistic submersible aeration and purification device

Abstract

This invention discloses a gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device. The device includes: an aeration zone for aeration, with an aerobic layer with high dissolved oxygen content installed at the upper end of the aeration zone, an anoxic layer with low dissolved oxygen content installed at the upper end of the aeration zone, and an anaerobic layer installed at the lower end of the anoxic layer; the aeration zone includes an aeration cylinder with a permeable inner cylinder containing an aeration component that sprays air horizontally; the aerobic layer includes a first packing cylinder. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by this invention, through the synergistic effect of aeration in the aeration zone and the gradient porosity packing layer, forms a stable dissolved oxygen gradient of "aerobic upper layer – anoxic middle layer – anaerobic lower layer," simultaneously meeting the functional requirements of nitrification, denitrification, and phosphorus removal.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device. Background Technology

[0002] Under my country's high-density intensive aquaculture model, the accumulation of uneaten feed and excrement from farmed organisms leads to excessive levels of pollutants such as ammonia nitrogen, nitrite nitrogen, and total phosphorus in water bodies, hindering the green development of the aquaculture industry. Ammonia nitrogen damages the mucous membrane structure of aquatic animal gill tissues, hindering oxygen exchange; nitrite nitrogen inhibits the oxygen-carrying capacity of hemoglobin, causing tissue hypoxia, and even low-concentration long-term exposure can significantly reduce aquaculture yield and product quality; excessive total nitrogen and total phosphorus easily induce eutrophication of water bodies, disrupting the aquatic ecological balance. The efficient and synergistic removal of these three pollutants is the core objective of water quality control.

[0003] Existing technology discloses a compound aeration device for controlling the gradient dissolved oxygen distribution, belonging to the field of wastewater treatment technology. It includes a wastewater treatment device body with an inspection hole at the top. One end of the device body has an inlet pipe, and the other end has an outlet pipe. The interior of the device body is divided into an anoxic zone, an anaerobic zone, and an aeration zone by a first, second, and third partition. The aeration zone is filled with nano-modified flexible packing material. Microporous aeration inlet pipes and perforated aeration inlet pipes are located on the sides of the aeration zone. This invention, through a compound aeration method combining perforated and microporous aeration pipes, ensures sufficient mass transfer, high oxygenation efficiency, and good nitrogen removal effect. Furthermore, the nano-modified flexible packing material has a well-developed pore structure, gradually forming a dissolved oxygen gradient from the surface to the interior, achieving short-range simultaneous nitrification and denitrification, improving the system's nitrogen removal efficiency, and ensuring stable effluent compliance with standards.

[0004] The aforementioned device is a central direct-fire design, which easily leads to uniform dissolved oxygen levels, making it impossible to create the aerobic environment required for nitrification and the anoxic or anaerobic environment required for denitrification.

[0005] Therefore, it is necessary to provide a gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device to solve the above-mentioned technical problems. Summary of the Invention

[0006] In view of the above situation and to overcome the defects of the prior art, the present invention provides a gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device that can achieve gradient dissolved oxygen, thereby forming an aerobic environment and an anoxic or anaerobic environment required for denitrification.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device includes: an aeration zone for aeration, an aerobic layer with high dissolved oxygen content installed at the upper end of the aeration zone, an anoxic layer with low dissolved oxygen content installed at the upper end of the aeration zone, and an anaerobic layer installed at the lower end of the anoxic layer. The aeration zone includes an aeration cylinder, which has a breathable inner cylinder and an aeration component inside the inner cylinder, which sprays air in a horizontal direction. The aerobic layer includes a first packing cylinder, in which a first packing material is placed, and a cover plate is detachably installed on the upper end of the first packing cylinder. Non-woven fabric is installed between the cover plate and the first packing cylinder. The anoxic layer includes a second packing cylinder, and a second packing material is placed inside the second packing cylinder; The anaerobic layer includes a third packing cylinder, the lower end of which is detachably fitted with a surrounding plate. A steel frame for supporting the cylinder is installed inside the surrounding plate, and the third packing material is placed inside the third packing cylinder within the surrounding plate. The porosity of the first, second, and third packing materials decreases sequentially. Adjacent packing materials are separated by an isolation component. The adjacent parts of the aeration cylinder, the first packing cylinder, the second packing cylinder, and the third packing cylinder are detachably connected. A steel frame is fixedly installed inside each of the aeration cylinder, the first packing cylinder, the second packing cylinder, and the third packing cylinder.

[0008] Preferably, the aeration assembly includes an aerator, the main body of which is a jellyfish cover. An air inlet pipe is fixedly installed and connected to the jellyfish cover. The interior of the jellyfish cover is an air chamber. Multiple horizontal air outlets are opened on the upper outer wall of the jellyfish cover. The air outlets are connected to the air chamber. The air inlet pipe passes through the aeration cylinder and the outer wall of the inner cylinder and is connected to the jellyfish cover. The air inlet pipe is detachably connected to the steel frame on the aeration cylinder.

[0009] Preferably, the jellyfish cover has a raised mounting block at its upper end, the mounting block being fixedly connected to the upper end of the jellyfish cover, and the interior of the mounting block being hollow.

[0010] Preferably, the hollow portion is connected to the air cavity inside the jellyfish cover, and a second air hole is opened on the inner wall of the mounting block. Air discharged from the first air hole on the air inlet pipe enters the air cavity through the hollow portion of the mounting block and the second air hole.

[0011] Preferably, the lower end of the jellyfish cover has a closed curved surface, and the tangent at the lowermost end of the curved surface extends in a downward inclined direction.

[0012] Preferably, the lower end of the enclosure panel is fixedly installed with a shelf, the lower end of the shelf is fixedly installed with multiple support legs, the steel frame includes an inner steel ring and an outer steel ring, the inner steel ring and the outer steel ring are fixedly connected by a connecting rod, and multiple vertical columns are fixedly installed circumferentially on the outer steel ring.

[0013] Preferably, the isolation component is a filter plate with multiple through holes on its surface, the outer diameter of the filter plate is the same as the outer diameter of the outer steel ring, the lower end of the outer steel ring is fixedly installed on the filter plate, the packing cylinder is located at the upper end of the filter plate, the inner cylinder is fixedly connected to the inner steel ring, and the aeration cylinder is fixedly connected to the outer steel ring.

[0014] Preferably, the enclosure plate is cylindrical, and the first, second, and third packing cylinders are also cylindrical. The third packing cylinder is threaded to the enclosure plate, and the adjacent ends of the enclosure plate, the first, second, and third packing cylinders are flanged together.

[0015] Preferably, the first filler has the following composition: 75% bio-enzyme charcoal, 20% sponge iron, and 5% zinc granules; the second filler has the following composition: 55% bio-enzyme charcoal, 30% decayed wood, and 15% bamboo; and the third filler has the following composition: 60% decayed wood and 40% bamboo.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention forms a stable dissolved oxygen gradient of “aerobic upper layer - anoxic middle layer - anaerobic lower layer” by the synergistic effect of aeration in the aeration zone, gradient porosity packing layer and natural flow of water, thus simultaneously meeting the functional requirements of nitrification, denitrification and biological phosphorus removal. (2) This invention adopts a multi-filler synergistic system of bio-enzyme charcoal, sponge iron, zinc granules, decayed wood and bamboo, combined with chemical precipitation, microbial degradation and physical adsorption, to achieve efficient nitrogen and phosphorus removal, with ammonia nitrogen removal rate ≥95%, nitrite nitrogen removal rate ≥99%, total nitrogen removal rate ≥50%, and total phosphorus removal rate ≥75%; (3) The packing cylinders of the present invention are installed by means of flange connection, which facilitates disassembly and maintenance. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention; Figure 2 A schematic diagram of the internal structure of the anaerobic layer aeration zone of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 3 This is a first cross-sectional view of the aeration zone of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 4This is a second cross-sectional view of the aeration zone of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 5 A cross-sectional view of the aerator in the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 A cross-sectional view of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 8 A cross-sectional view of the aeration zone of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 9 A cross-sectional view of the aerobic layer of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention. Figure 10 A cross-sectional view of the anoxic layer in the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration purification device provided by the present invention. Figure 11 This is a cross-sectional view of the anaerobic layer of the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration purification device provided by the present invention.

[0018] The corresponding names of the attached figures are as follows: 10, Aeration Zone; 12, Aeration Cylinder; 13, Filter Plate; 14, Inner Cylinder; 15, Air Inlet Pipe; 151, First Air Hole; 16, Aerator; 161, Jellyfish Cover; 162, Air Outlet; 163, Air Chamber; 164, Second Air Hole; 165, Mounting Block; 17, Steel Frame; 171, Inner Steel Ring; 172, Outer Steel Ring; 173, Column; 20, Aerobic Layer; 21, First Packing Cylinder; 22, Cover Plate; 221, Non-woven Fabric; 30, Anoxic Layer; 31, Second Packing Cylinder; 40, Anaerobic Layer; 41, Third Packing Cylinder; 42, Enclosure; 421, Shelf; 422, Support Leg. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0020] Example 1: like Figure 1 As shown, the gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device provided by the present invention includes: an aeration zone 10 for aeration, an aerobic layer 20 with high dissolved oxygen content installed at the upper end of the aeration zone 10, an anoxic layer 30 with low dissolved oxygen content installed at the lower end of the aeration zone 10, and an anaerobic layer 40 installed at the lower end of the anoxic layer 30.

[0021] like Figure 2 , Figure 7As shown, the anaerobic layer 40 includes a cylindrical enclosure 42, which is open at the top and bottom and closed on all sides. The enclosure 42 is made of 304 stainless steel with a thickness of 8mm to ensure its corrosion resistance and structural strength in the long-term underwater working environment. A disc-shaped shelf 421 is welded and fixed to the bottom of the inner side of the enclosure 42 to support all the components above it. On the lower surface of the shelf 421, four legs 422 are welded and fixed vertically at equal intervals along the circumference. The legs 422 are made of stainless steel pipes. Each leg 422 has a foot pad welded to its lower end. The entire device can be fixed to the pond foundation by bolts or the like through the foot pads.

[0022] The upper inner wall of the enclosure plate 42 has an internal thread, and the lower outer wall of the third packing cylinder 41 has an external thread that matches it. The third packing cylinder 41 is installed on the enclosure plate 42 through the external thread at its lower end. The third packing cylinder 41 is made of stainless steel and has multiple through holes on its surface for water to pass through.

[0023] A steel frame 17 is fixedly installed inside the third stuffing box 41. The steel frame 17 is a frame structure adapted to the internal specifications of the third stuffing box 41, such as... Figure 2 As shown, the steel frame 17 is welded and fixed to the inner wall of the third packing cylinder 41 (the specific structure of the steel frame 17 will be described in detail below).

[0024] On the other hand, such as Figure 3-4 As shown, the aeration cylinder 12 is a cylindrical structure with a closed outer wall and open at both ends. An inner cylinder 14 is coaxially arranged inside it. The inner cylinder 14 is cylindrical with open at both ends and closed around its sides to prevent horizontal air that has been processed by the aerator 12 from being sprayed directly out of the device, thus preventing dissolved oxygen from being effectively utilized by the upper aerobic layer 20.

[0025] To maintain the stability of the device structure, a steel frame 17 is also installed between the aeration cylinder 12 and the inner cylinder 14 for support. The steel frame 17 includes an inner steel ring 171 and an outer steel ring 172, both of which are circular and concentrically arranged, and are fixed by welding with four radially distributed connecting rods. Four vertically upward columns 173 are evenly welded on the outer steel ring 172 along the circumference. The bottom of the inner cylinder 14 is welded to the inner steel ring 171, and the bottom of the aeration cylinder 12 is welded to the outer steel ring 172.

[0026] An aerator 16 is installed at the center of the inner cylinder 14, such as Figure 4 , Figure 5-6As shown, the main body of the aerator 16 consists of three jellyfish-shaped covers 161 on the same vertical line. The overall shape is jellyfish-shaped or umbrella-shaped. Each jellyfish cover 161 has a downward-opening, closed arc-shaped block with a hollow air chamber 163 inside, and an upward-protruding mounting block 165. On the upper outer wall of the jellyfish cover 161, i.e. the arc surface of its "umbrella cap", multiple air outlets 162 are evenly opened along the circumference. The axis of these air outlets 162 is in the horizontal direction, and all air outlets 162 are connected to the internal air chamber 163.

[0027] The mounting block 165 is cylindrical with a hollow interior. It is fixed by welding or integral molding at the upper end of the mounting block 165. Its hollow inner cavity is connected to the air cavity 163 inside the jellyfish cover 161. Two symmetrical second air holes 164 are opened on the inner wall of the mounting block 165.

[0028] The vertical end of the air inlet pipe 15 is inserted vertically into the hollow cavity inside the mounting block 165 and the end is closed. Two symmetrical first air holes 151 are opened on the pipe wall. After the jellyfish cover 161 is assembled with the air inlet pipe 15, the first air hole 151 and the second air hole 164 are aligned. The other end of the air inlet pipe 15, i.e. the air inlet end, passes through the aeration cylinder 12 and the inner cylinder 14 and is connected to the external air pump. The part of the air inlet pipe 15 located inside the aeration cylinder 12 is tied to the steel frame 17 with pipe clamps or cable ties.

[0029] The other two jellyfish covers 161 located at the lower end have the same structure and working principle as described above. The difference is that the mounting blocks 165 of the two lower jellyfish covers 161 are connected to and sealed with the air inlet pipe 15. The structure of the connection between the jellyfish cover 161 and the air inlet pipe 15 and the air passage structure for airflow movement are the same.

[0030] During operation, air enters the air chamber 163 through the air inlet pipe 15, the first air hole 151, and the second air hole 164, and is finally ejected horizontally from the air outlet 162, forming a horizontal liquid film aeration layer that adheres tightly to the bottom of the device, preventing bubbles from floating vertically upward and increasing the contact time between the air and the water to be treated.

[0031] Please see Figure 4 , Figure 7 and Figure 9-11 The aerobic layer 20, the anoxic layer 30, and the anaerobic layer 40 of the device are each composed of an independent cylindrical packing cylinder, namely the first packing cylinder 21, the second packing cylinder 31, and the third packing cylinder 41. These three packing cylinders have similar structures and are filled with packing materials in different states.

[0032] As mentioned above, the lower end of the third packing cylinder 41 at the bottom is provided with an external thread, which is connected to the internal thread of the surrounding plate 42. The upper and lower ends of the first packing cylinder 21 and the second packing cylinder 31, as well as the lower end of the third packing cylinder 41, are all provided with flanges. The first packing cylinder 21 and the aeration cylinder 12, as well as the second packing cylinder 31 and the third packing cylinder 41, are all detachably sealed by using stainless steel bolts and gaskets through the flanges. The top of the first packing cylinder 21 and the cover plate 22 are also connected by a flange through the same structure.

[0033] like Figure 4 As shown, the isolation component is a circular filter plate 13 with evenly distributed through holes for air passage on its surface. The outer diameter of the circular filter plate 13 is the same as the outer diameter of the outer steel ring 172. The filter plate 13 is made of stainless steel. A filter plate 13 is fixedly installed at the bottom of each packing cylinder. The upper end of the filter plate 13 is welded and fixed to the lower end of the outer steel ring 172 to block and constrain different types of packing in different areas.

[0034] Inside the first packing cylinder 21 and the second packing cylinder 31, steel frames 17 are also fixedly installed to maintain structural stability. The steel frame 17 consists of an inner steel ring 171, an outer steel ring 172 and a column 173. The outer side of the steel frame 17 is welded and fixed to the inner wall of the packing cylinder.

[0035] The first packing cylinder 21, the second packing cylinder 31, and the third packing cylinder 41 are respectively filled with the first packing, the second packing, and the third packing. The porosity of the three packings decreases in sequence to achieve natural decay of dissolved oxygen. The porosity of the first packing is 60%~70%, the porosity of the second packing is 30%~40%, and the porosity of the third packing is 20%~30%.

[0036] The volume ratio of each packing is as follows: First filler: 75% bio-enzyme charcoal, 20% sponge iron, 5% zinc granules; The second filler consists of 55% bio-enzyme charcoal, 30% rotten wood, and 15% bamboo. The bamboo is in segments 10-20mm in length and is interspersed horizontally in the filler, with a vertical spacing of 10cm between adjacent horizontal bamboo segments. The third filler consists of 60% rotten wood and 40% bamboo, and is loosely stacked.

[0037] like Figure 7 , Figure 9 As shown, a layer of non-woven fabric 221 is laid between the cover plate 22 and the top of the first packing cylinder 21. The non-woven fabric 221 has a pore size of 0.1mm and is made of polyester fiber. It is used to block fine packing particles and form a physical barrier layer to enhance the dissolved oxygen barrier effect. In addition, a gas-liquid exchange gap of 5cm height can be reserved at the top of the first packing cylinder 21, that is, between the non-woven fabric 221 and the cover plate 22.

[0038] In use, the device is first installed at the bottom of the aquaculture pond via the support legs 422, with the entire device submerged in water. The air inlet pipe 15 is connected to an external air pump. After starting the air pump, compressed air enters the aerator 16 and is horizontally ejected from the air outlet 162 of the jellyfish cover 161. Because the aeration direction is horizontal, the bubbles cannot rise directly vertically. Some of the rising bubbles are blocked by the arc-shaped surface of the lower surface of the jellyfish cover 161, thus being forced to move downwards and flow obliquely downwards along the tangent of the arc-shaped surface. Therefore, the highly oxygenated water is forcibly confined within the aeration zone 10 and the surrounding area. In the oxygen layer 20 region, an aerobic zone with DO ≥ 5 mg / L is formed. The water flows upward under the action of gas flow. During this process, due to the effect of the jellyfish cover 161 and the cross-flow of some water, some water flows downward to the anoxic layer 30. Unlike the high-density oxygen in the aerobic layer 20, the oxygen in this part mainly relies on the cross-flow of water and the downward flow of some water caused by the obstruction of the jellyfish cover 161. Therefore, the oxygen content in this part is relatively low. Meanwhile, the water in the anaerobic layer 40 is replenished and deeply treated through slow infiltration.

[0039] Example 2: The device described in Example 1 was applied to a 5-mu (approximately 0.33 hectares) freshwater grass carp farming pond for in-situ purification experiments. The pond was 1.8 m deep, and the initial water quality was: ammonia nitrogen 1.6 mg / L, nitrite nitrogen 4.5 mg / L, and total phosphorus 0.8 mg / L. Three devices of the present invention were evenly arranged in the pond.

[0040] The system operated continuously for three months, with regular water quality monitoring. Results showed that dissolved oxygen levels remained stable at 5.5 mg / L at the bottom (aerobic zone), 1.2 mg / L in the middle (anoxic zone), and 0.3 mg / L at the top (anaerobic zone), forming a stable and ideal dissolved oxygen gradient. The water purification effect was significant: ammonia nitrogen concentration ≤0.02 mg / L, removal rate reached 98.75%; nitrite nitrogen concentration ≤0.005 mg / L, removal rate as high as 99.89%; total nitrogen removal rate 87%; and total phosphorus removal rate 95%. Simultaneously, grass carp survival rate increased by 15% and growth rate increased by 10% compared to conventional farming. No clogging of aeration units or packing material compaction occurred during operation, and there were no issues with rotting wood or bamboo emitting foul odors.

[0041] Example 3: Packing material treatment: Bio-enzyme charcoal: Impregnated with a polymer surface modifier and a microbial enzymatic reaction regulator under negative pressure to neutralize the negative surface charge, then sieved to a particle size of 8-30 mm, with a bulk density controlled at 0.3-0.34 kg / m³, resulting in a specific surface area of ​​100-300 m² / g and a microbial colonization rate of up to 2.1 × 10¹. 0 ~10¹² pieces / g.

[0042] Sponge iron: Use 10% dilute hydrochloric acid for pickling and rust removal treatment for 1 hour, and then perform pore treatment to ensure that its porosity is ≥50%, and then sieve to 8-30mm.

[0043] Zinc granules: These undergo microsphere treatment, with a particle size controlled to 8-30 mm. The surface oxide layer is then removed by acid washing with 10% dilute sulfuric acid, followed by drying for later use. The addition amount should not exceed 5% of the total packing volume, ensuring that the zinc ion concentration in the effluent is ≤0.05 mg / L.

[0044] Rotten wood: Select naturally rotten hardwood (such as oak or elm), cut it into 10-20mm sections, degrease it at 80℃ for 2 hours, then soak it in food-grade plant-derived preservative solution for 3 hours, and finally dry and sieve it to 8-30mm.

[0045] Bamboo: Select moso bamboo, cut into 10-20mm sections, degrease with high-temperature steam at 120℃ for 1 hour, then soak in food-grade preservative solution for 2 hours, dry, and sieve to 8-30mm.

[0046] Working principle: When the gradient dissolved oxygen guided multi-filler synergistic submersible aeration and purification device is running, compressed air enters the air chamber 163 inside the jellyfish cover 161 through the air inlet pipe 15, the first air hole 151, and the second air hole 164, and finally sprays out from the horizontal air outlet 162 on the upper outer wall of the jellyfish cover 161, forming a horizontal liquid film aeration layer. This forces the high dissolved oxygen water to be confined in the aeration zone 10 and the aerobic layer 20, forming an aerobic zone with DO ≥ 5 mg / L. Under the action of air, the water flows upward through the aerobic layer 20 and a small amount flows into the lower anoxic layer 30. Therefore, the dissolved oxygen content of the water in the first filler, the second filler, and the third filler decreases sequentially. An anoxic environment with DO = 0.5~2.0 mg / L is formed in the anoxic layer 30, and an anaerobic environment with DO ≤ 0.5 mg / L is formed in the anaerobic layer 40, completing the entire process of aerobic nitrification, anoxic denitrification, anaerobic deep denitrification, and chemical-biological-physical synergistic phosphorus removal.

[0047] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device, characterized in that, include: An aeration zone (10) for aeration, wherein an aerobic layer (20) with high dissolved oxygen is installed at the upper end of the aeration zone (10), an anoxic layer (30) with low dissolved oxygen is installed at the lower end of the aeration zone (10), and an anaerobic layer (40) is installed at the lower end of the anoxic layer (30). The aeration zone (10) includes an aeration cylinder (12), which has a breathable inner cylinder (14) and an aeration component in the inner cylinder (14) that sprays air in a horizontal direction. The aerobic layer (20) includes a first packing cylinder (21), in which a first packing is placed, and a cover plate (22) is detachably installed on the upper end of the first packing cylinder (21), and a non-woven fabric (221) is installed between the cover plate (22) and the first packing cylinder (21). The anoxic layer (30) includes a second packing cylinder (31), and a second packing is placed inside the second packing cylinder (31); The anaerobic layer (40) includes a third packing cylinder (41), and a surrounding plate (42) is detachably installed at the lower end of the third packing cylinder (41). A steel frame (17) for supporting it is installed inside the surrounding plate (42), and the third packing is placed inside the third packing cylinder (41). The porosity of the first packing, the second packing and the third packing decreases in sequence. Adjacent packing types are separated by an isolation component. The adjacent parts of the aeration cylinder (12), the first packing cylinder (21), the second packing cylinder (31) and the third packing cylinder (41) are detachably connected. A steel frame (17) is fixedly installed inside the aeration cylinder (12), the first packing cylinder (21), the second packing cylinder (31) and the third packing cylinder (41).

2. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 1, characterized in that, The aeration assembly includes an aerator (16), the main body of which is a jellyfish cover (161). An air inlet pipe (15) is fixedly installed and connected to the jellyfish cover (161). The interior of the jellyfish cover (161) is an air chamber (163). Multiple horizontal air outlets (162) are opened on the upper outer wall of the jellyfish cover (161). The air outlets (162) are connected to the air chamber (163). The air inlet pipe (15) passes through the aeration cylinder (12) and the outer wall of the inner cylinder (14) and is connected to the jellyfish cover (161). The air inlet pipe (15) is detachably connected to the steel frame (17) on the aeration cylinder (12).

3. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 2, characterized in that, The upper end of the jellyfish cover (161) has a protruding mounting block (165), which is fixedly connected to the upper end of the jellyfish cover (161), and the interior of the mounting block (165) is hollow.

4. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 3, characterized in that, The hollow part is connected to the air cavity (163) inside the jellyfish cover (161). The inner wall of the mounting block (165) is provided with a second air hole (164). The air discharged from the first air hole (151) on the air inlet pipe (15) enters the air cavity (163) through the hollow part of the mounting block (165) and the second air hole (164).

5. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 4, characterized in that, The lower end of the jellyfish cover (161) has a closed curved surface, and the tangent at the lowest end of the curved surface extends in a downward inclined direction.

6. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 1, characterized in that, The lower end of the enclosure (42) is fixedly installed with a shelf (421), and the lower end of the shelf (421) is fixedly installed with multiple support legs (422). The steel frame (17) includes an inner steel ring (171) and an outer steel ring (172). The inner steel ring (171) and the outer steel ring (172) are fixedly connected by a connecting rod. Multiple vertical columns (173) are fixedly installed circumferentially on the outer steel ring (172).

7. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 6, characterized in that, The isolation component is a filter plate (13) with multiple through holes on its surface. The outer diameter of the filter plate (13) is the same as the outer diameter of the outer steel ring (172). The filter plate (13) is fixedly installed at the lower end of the outer steel ring (172). The packing cylinder is located at the upper end of the filter plate (13). The inner cylinder (14) is fixedly connected to the inner steel ring (171). The aeration cylinder (12) is fixedly connected to the outer steel ring (172).

8. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 7, characterized in that, The enclosure plate (42) is cylindrical, and the first packing cylinder (21), the second packing cylinder (31) and the third packing cylinder (41) are also cylindrical. The third packing cylinder (41) is threadedly connected to the enclosure plate (42), and the adjacent ends of the enclosure plate (42), the first packing cylinder (21), the second packing cylinder (31) and the third packing cylinder (41) are connected by flanges.

9. The gradient dissolved oxygen-guided multi-filler synergistic submersible aeration and purification device according to claim 1 or 8, characterized in that, The first filler has the following composition: 75% bio-enzyme charcoal, 20% sponge iron, and 5% zinc granules; the second filler has the following composition: 55% bio-enzyme charcoal, 30% rotten wood, and 15% bamboo; and the third filler has the following composition: 60% rotten wood and 40% bamboo.

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