Sewage treatment biological aerated filter

Abstract

The invention belongs to the field of sewage treatment, and discloses a sewage treatment biological aerated filter which continuously changes the running direction and running path of oxygen, so that a polyhedral filter material is in full contact with the oxygen in multiple directions, the transfer efficiency of the oxygen and the utilization rate of the filter material are improved, and the sewage treatment efficiency is effectively improved. The biological aerated filter comprises a filter body, a filter plate, a supporting layer, a filter material layer and an aeration ring, the filter plate, the supporting layer, the filter material layer and the aeration ring are arranged in the filter body, the filter plate is located on the lower portion of the filter body and fixedly connected with the inner wall of the filter body, the supporting layer is laid on the filter plate, the filter material layer is laid on the supporting layer, and the aeration ring is located in the filter material layer; a pipe gallery is formed below the filter plate, and a water purification area is formed above the filter material layer; a sewage inlet pipe, a backwashing water inlet pipe and an air inlet pipe are arranged on the side wall of the pipe gallery; a water outlet is formed in the side wall of the water purification area; and an aeration pipe is arranged in the supporting layer.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a sewage treatment biological aeration filter. Background Art

[0002] Aerated biological filters for sewage treatment integrate filtration, retention, and biosorption, offering excellent filtration and adsorption, high treatment efficiency, and excellent effluent quality. Oxygen provided by the aeration tubes rises from the bottom up into the filter media layer, where sewage flows upward through it, oxidizing and degrading it. However, the oxygen's path remains fixed, moving upward, and much of the filter media is tilted, preventing the polyhedral filter media from fully contacting the oxygen, reducing its utilization. Backwashing often occurs before the filter media within the filter media layer is fully oxidized and degraded, shortening the backwash interval and reducing production efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a sewage treatment aeration biological filter, which continuously changes the direction and path of oxygen flow, so that the polyhedron filter material is fully in contact with oxygen in multiple directions, improves the oxygen transfer efficiency and the utilization rate of the filter material, improves the oxidation and degradation effect of sewage, and effectively improves the sewage treatment efficiency.

[0004] To solve the above technical problems, an embodiment of the present invention provides a sewage treatment biological aeration filter, comprising: A sewage treatment aerated biological filter comprises a tank body, and a filter plate, a supporting layer, a filter material layer and an aeration ring arranged in the tank body. The filter plate is located at the lower part of the tank body and is fixedly connected to the inner wall of the tank body. The supporting layer is laid on the filter plate, the filter material layer is laid on the supporting layer, and the aeration ring is located in the filter material layer. A pipe gallery is formed below the filter plate, and a water purification zone is formed above the filter material layer. The side walls of the pipe gallery are provided with a sewage inlet pipe, a backwash inlet pipe and an air inlet pipe, and the side walls of the water purification zone are provided with a water outlet. The supporting layer is provided with a pipe gallery. Aeration pipe; the top and bottom ends of the aeration ring are both provided with openings, and the end face cross-section of the aeration ring is a bilaterally symmetrical arc shape; the end face width of the aeration ring below the parting surface of the aeration ring gradually increases from bottom to top; the end face width of the aeration ring above the parting surface gradually decreases from bottom to top; the wall surface of the aeration ring is provided with a wall cavity, and the bottom surface is provided with a bottom cavity, the wall cavity and the bottom cavity are connected to each other, and the bottom cavity is connected to the air inlet pipe; the outer wall of the wall cavity is provided with an external aeration hole, and the inner wall is provided with an inner aeration hole.

[0005] As a preferred example, the aeration pipes are interconnected and arranged in parallel in the horizontal direction; and single-hole membrane air diffusers are evenly arranged on the aeration pipes.

[0006] As a preferred example, the top of the aeration ring is 500 to 1500 mm higher than the top of the supporting layer.

[0007] As a preferred example, the aeration ring is in the shape of a strip, and the axis of the aeration ring is perpendicular to the length direction of the tank body; or, the aeration ring is in the shape of a spherical segment.

[0008] As a preferred example, the bottom cavity is an annular cavity.

[0009] As a preferred example, the top opening area of ​​the aeration ring is larger than the bottom opening area.

[0010] As a preferred example, the axis of the inner aeration hole intersects with the axis of the aeration ring; the axis of the outer aeration hole intersects with the axis of the aeration ring.

[0011] As a preferred example, the inner aeration holes are evenly distributed on the inner wall of the aeration ring, and the outer aeration holes are evenly distributed on the outer wall of the aeration ring. The pore diameters of the inner aeration holes and the outer aeration holes are both 80-120 μm.

[0012] As a preferred example, the aeration volume of the top opening of the aeration ring is equal to aQ1S 上 / S 下 , where Q1 represents the aeration volume of the aeration tube in the inner cavity of the aeration ring, S 上 Indicates the opening area at the top of the aeration ring, S 下 It represents the bottom opening area of ​​the aeration ring, a represents the adjustment coefficient, and the value range of a is 1.1 to 1.3.

[0013] As a preferred example, the sum of the aeration volume of the inner aeration holes and the outer aeration holes of the aeration ring is equal to 10-30% of the aeration volume of the aeration tube.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: the sewage treatment aeration biological filter of the present invention continuously changes the direction and path of oxygen flow, so that the polyhedron filter material is fully in contact with oxygen in multiple directions, thereby improving the oxygen transfer efficiency and the utilization rate of the filter material, improving the oxidation and degradation effect of sewage, and effectively improving the sewage treatment efficiency. The sewage treatment aeration biological filter includes a tank body, and a filter plate, a supporting layer, a filter material layer and an aeration ring arranged in the tank body. The top and bottom ends of the aeration ring are both provided with openings, and the end face cross-section of the aeration ring is symmetrically arc-shaped; the end face width of the aeration ring gradually increases from bottom to top below the parting surface of the aeration ring; the end face width of the aeration ring gradually decreases from bottom to top above the parting surface of the aeration ring; the wall surface of the aeration ring is provided with a wall cavity, and the bottom surface is provided with a bottom cavity, the wall cavity and the bottom cavity are connected to each other, and the bottom cavity is connected to the air inlet pipe; the outer wall of the wall cavity is provided with an external aeration hole, and the inner wall is provided with an inner aeration hole. By utilizing the first airflow injected from the external aeration holes and the internal aeration holes, and the second airflow injected from the aeration pipe, the airflow path is continuously changed, the oxygen transfer efficiency is improved, and different surfaces of the filter material are fully in contact with oxygen, thereby increasing the utilization rate of the filter material, improving the oxidation and degradation effect of sewage, and extending the backwashing interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of an embodiment of the present invention; Figure 2 2. It is a schematic structural diagram of an aeration ring in an embodiment of the present invention; Figure 3 Schematic diagram of aeration effect between aeration rings in an embodiment of the present invention; Figure 4 This is a schematic diagram of the aeration effect inside the aeration ring in an embodiment of the present invention: Figure 5 Schematic diagram of the reflecting fluid on the outer wall of the aeration ring in an embodiment of the present invention; Figure 6 This is a layout diagram of an aeration ring in an embodiment of the present invention.

[0016] The figure includes: sewage inlet pipe 1, backwash inlet pipe 2, air inlet pipe 3, aeration pipe 4, filter material layer 5, water purification area 6, aeration ring 7, bottom cavity 71, wall cavity 72, external aeration holes 73, internal aeration holes 74, supporting layer 8, filter plate 9, and pipe gallery 10. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0018] like Figure 1 As shown, a sewage treatment biological aerated filter tank according to an embodiment of the present invention includes a tank body, a filter plate 9, a support layer 8, a filter media layer 5, and an aeration ring 7 disposed therein. The filter plate 9 is located at the bottom of the tank body and fixedly connected to the inner wall of the tank body. The support layer 8 is laid above the filter plate 9, the filter media layer 5 is laid above the support layer 8, and the aeration ring 7 is located within the filter media layer 5. A pipe gallery 10 is formed below the filter plate 9, and a clean water zone 6 is formed above the filter media layer 5. The sidewalls of the pipe gallery 10 are provided with a sewage inlet pipe 1, a backwash inlet pipe 2, and an air inlet pipe 3. The sidewalls of the clean water zone 6 are provided with a water outlet. An aeration pipe 4 is provided within the support layer 8. The aeration ring 7 has openings at both the top and bottom ends, and its end face cross-section is a bilaterally symmetrical arc. Below the parting surface of the aeration ring 7, the end face width of the aeration ring 7 gradually increases from bottom to top. The parting surface of the aeration ring 7 is a horizontal plane and passes through the maximum horizontal width of the aeration ring 7 cross section. Figure 2 As shown by plane AA in FIG. The cross-section of aeration ring 7 gradually increases in width from the lowest end to the parting surface and gradually decreases from the parting surface to the top. Aeration ring 7 has a wall cavity 72 on its wall surface and a bottom cavity 71 on its bottom surface. Wall cavity 72 and bottom cavity 71 are interconnected, and bottom cavity 71 is connected to the air inlet pipe 3. External aeration holes 73 are defined on the outer wall of wall cavity 72, and internal aeration holes 74 are defined on the inner wall.

[0019] During operation of the sewage treatment biological aerated filter of the above-described embodiment, sewage enters the pipe gallery 10 from the sewage inlet pipe 1 and flows upward, sequentially, through the filter plates 9, support layer 8, and filter media layer 5. After filtration and adsorption by the filter media layer 5, the sewage becomes clear water, which then flows out of the outlet of the clean water area 6. The filter plates 9 primarily serve as support, supporting the aeration ring 7, support layer 8, and filter media layer 5 located above them. The support layer 8 primarily serves as support and filtering. The support layer 8 can be made of pebbles with good strength and chemical stability to stabilize the filter media layer 5. The support layer 8 can filter larger pollutants in the sewage, such as sand particles. The support layer 8 supports the filter media layer 5 and aeration ring 7 located above it. The filter media layer 5 primarily serves as filtering and adsorption. The filter media in the filter media layer 5 is polyhedral, with each filter media randomly arranged in different positions. The filter media has a high porosity, a large specific surface area, and strong biological adhesion. The support layer 8 is provided with an aeration pipe 4. The secondary airflow exiting aeration pipe 4 moves vertically upward, aerating and oxygenating the filter media. Valves are installed at the inlet ends of the sewage inlet pipe 1 and the backwash inlet pipe 2. Regulating valves are installed at the inlet ends of the air inlet pipe 3 and aeration pipe 4 to control the amount and pressure of air entering the biological aerated filter. An outlet pipe is installed outside the tank, connected to the outlet. A valve is installed on the outlet pipe to control the opening and closing of the outlet.

[0020] The aeration ring 7 has openings at both the top and bottom, and both the inner and outer portions of the aeration ring are filled with filter media. A portion of the second airflow flowing out of the aeration tube 4 flows into the inner portion of the aeration ring 7 through the bottom opening and then out of the aeration ring 7 through the top opening, oxidizing and degrading the wastewater within the filter media layer within the inner portion of the aeration ring 7. This aeration volume is Q1. The remaining portion of the second airflow flows outside the aeration ring 7. The outer aeration holes 73 of the aeration ring spray the first airflow toward the outer portion of the aeration ring, while the inner aeration holes 74 spray the first airflow toward the inner portion of the aeration ring. The first airflow serves as auxiliary oxygenation (aeration in different directions), while the second airflow serves as the primary oxygenation.

[0021] In the above embodiment, the end face of the aeration ring 7 has a bilaterally symmetrical arc-shaped cross-section. Below the parting surface of the aeration ring 7, the end face width of the aeration ring 7 gradually increases from bottom to top. Above the parting surface, the end face width of the aeration ring 7 gradually decreases from bottom to top. From bottom to top, the cross-sectional area of ​​the aeration ring first gradually increases, increasing the space for air flow within the ring. The main flow direction of air at the sides (for strip-shaped aeration rings, the sides are on both sides; for spherical aeration rings, the sides are on all sides) is diffuse, with air gradually spreading outward. When reaching the parting surface, the cross-sectional area reaches its maximum. Moving upward, the cross-sectional area of ​​the aeration ring gradually decreases, reducing the air flow space and increasing the air velocity, thereby continuously changing the air flow direction. The main flow direction of air at the sides converges inward, gradually converging toward the center, thereby enhancing the air flow effect and the probability of contact with the different surfaces of the polyhedral filter media.

[0022] Preferably, the aeration tubes 4 are interconnected and arranged horizontally and parallel to each other. Single-porous membrane air diffusers are evenly distributed across the aeration tubes 4. This ensures uniform pressure distribution of the second airflow emitted by each of the single-porous membrane air diffusers located on the aeration tubes 4, preventing areas within the pool from experiencing strong oxygenation while areas within the pool experience weak oxygenation. When air at a certain pressure is introduced into the aeration tubes 4, the second airflow passes through the single-porous membrane air diffusers, aerating the support layer from bottom to top, oxidizing and degrading the wastewater within the filter layer 5.

[0023] Preferably, the top of the aeration ring 7 is 500 to 1500 mm higher than the top of the support layer 8. The airflow at the top opening of the aeration ring interacts with the external airflow, continuously changing direction, and aerating and oxygenating the filter material above.

[0024] Preferably, the aeration ring 7 is in the shape of a strip, and the axis of the aeration ring 7 is perpendicular to the length direction of the tank body; or, the aeration ring 7 is in the shape of a spherical segment. The aeration ring 7 can have various shapes. In this preferred example, the aeration ring 7 is in the shape of a strip, and the cross section is a symmetrical arc. The top and bottom ends of the aeration ring 7 are provided with openings. The bottom surface of the aeration ring 7 is provided with a bottom cavity, which is located on both sides of the bottom opening. As another shape, the aeration ring 7 is in the shape of a spherical segment, that is, a plane is used to cut off the upper part above the plane at the upper part of the sphere, and another plane is used to cut off the part below the plane at the lower part of the sphere. The bottom surface of the spherical segment has an annular bottom cavity, which is connected to the wall cavity of the spherical segment. As Figure 6 As shown, spherical aeration rings 7 are arranged in rows and staggered within the filter layer. The aeration rings 7 are arranged in rows with a certain distance between them. Adjacent rows of aeration rings 7 are staggered. This allows the first airflows ejected from the outer aeration holes 74 of different aeration rings to collide and mix in multiple directions, ensuring that different surfaces of the filter media are fully exposed to oxygen, thereby improving filter media utilization.

[0025] Preferably, the bottom cavity 71 is an annular cavity. This allows the airflow from the air inlet pipe 3 to flow evenly into the wall cavity 72, preventing areas of strong and weak airflow in the wall cavity 72. When air at a certain pressure is introduced into the air inlet pipe 3, the air enters the bottom cavity 71 and then into the wall cavity 72.

[0026] Preferably, the top opening area of ​​the aeration ring 7 is larger than the bottom opening area. In this way, the aeration ring 7 has inward aeration, which balances the aeration volume per unit area and is slightly greater than the aeration intensity at the bottom.

[0027] Preferably, the axis of the inner aeration hole 74 intersects with the axis of the aeration ring 7, and the axis of the outer aeration hole 73 intersects with the axis of the aeration ring. When air at a certain pressure, i.e., a first airflow, is introduced into the inlet pipe 3, the first airflow enters the wall cavity and is sprayed through the inner aeration holes 74 toward the filter material layer in the inner cavity of the aeration ring 7. This aeration volume is the inner aeration volume Q2. Here, along the inner wall of the aeration ring 7, from bottom to top, the aeration direction gradually changes from an upward inclination to a downward inclination, thereby oxidizing and degrading the sewage. Simultaneously, the first airflow is sprayed through the outer aeration holes 73 toward the filter material layer outside the aeration ring 7. This aeration volume is Q3. Here, along the outer wall of the aeration ring 7, from bottom to top, the aeration direction gradually changes from a downward inclination to an upward inclination, thereby oxidizing and degrading the sewage. Thus, the angles of the first airflow ejected from different inner aeration holes 74 and different outer aeration holes 73 are different. The first airflows at different angles act on the filter materials placed at different angles to enhance the oxidation and degradation effect of the sewage.

[0028] Preferably, the inner aeration holes 74 are evenly distributed on the inner wall of the aeration ring 7, and the outer aeration holes 73 are evenly distributed on the outer wall of the aeration ring 7. The pore diameters of the inner aeration holes 74 and the outer aeration holes 73 are both 80 to 120 μm. The even distribution of the inner aeration holes 74 and the outer aeration holes 73 allows the filter media in the filter media layer 5 to be more evenly oxygenated by the first airflow.

[0029] Preferably, the aeration volume of the top opening of the aeration ring 7 is equal to aQ1S 上 / S 下 , where Q1 represents the aeration volume of the aeration tube 4 in the inner cavity of the aeration ring 7, S 上 Indicates the top opening area of ​​the aeration ring 7, S 下 S represents the bottom opening area of ​​the aeration ring 7, a represents the adjustment coefficient, and the value range of a is 1.1 to 1.3. 上 Greater than S 下 This can ensure that the aeration intensity at the top of the aeration ring 7 is greater than that at the bottom, thereby oxygenating the filter material inside the aeration ring in multiple directions and oxidizing and degrading the sewage in multiple directions.

[0030] Preferably, the sum of the aeration volumes of the inner aeration holes 74 and the outer aeration holes 73 of the aeration ring 7 is equal to 10-30% of the aeration volume of the aeration tube 4. This aeration volume serves as an auxiliary aeration volume for the aerated biological filter to enhance aeration and mutual cutting effects in multiple directions, improve the oxygen transfer efficiency, and enhance the oxidative degradation efficacy of filter media in multiple directions. In this preferred example, the aeration tube 4 is used as the main method for aerating and oxygenating the filter media, while the aeration ring 7 is used as an auxiliary method for aerating and oxygenating the filter media. Reasonably distribute the air volume because the depth of the filter material layer is greater than the height of the aeration ring, and the part above the aeration ring needs to continue to be aerated and oxygenated.

[0031] In the above embodiment, compressed air enters the aeration ring 7 and is ejected in different directions from the inner and outer aeration holes 74 and 73, respectively. Below the parting surface of the aeration ring 7, air is ejected downward and outward from the outer aeration holes 73 on the left and right sides of the aeration ring at different heights, radii, and angles. From bottom to top, the angle between the ejection direction and the horizontal plane gradually decreases. This downward, tilted airflow within the filter media layer at different angles aerates and oxygenates different surfaces of the filter media, increasing the probability of contact with filter media surfaces at different inclinations, enhancing the contact area between air and filter media, and improving the ability to oxidize and degrade wastewater. A second airflow, ejected upward from different positions in the X-direction (the length of the tank), aerates and oxygenates the filter media on vertical surfaces within the filter media layer, promoting oxidative degradation of the wastewater. After the first and second airflows aerate and oxygenate the filter media in different directions within the filter media layer, due to their different directions, they intensively intersect upon encounter, resulting in smaller and denser bubbles. At different heights, the spray radius varies, so the direction of air flow after cutting through different heights also changes continuously, allowing more oxygen to dissolve in the water. At the same time, by constantly changing direction and increasing the oxygen's movement path, aeration and oxygenation are carried out in multiple directions within the filter layer, further increasing the contact area with the filter material and improving the oxidation and degradation of wastewater.

[0032] Air from different directions below the parting surface of the left aeration ring 7 mixes and cuts with each other, then changes direction to aerate and oxygenate different surfaces of the filter media in the filter layer 5 along different paths and directions. Air from different directions below the parting surface of the right aeration ring 7 mixes and cuts with each other, then changes direction to aerate and oxygenate different surfaces of the filter media in the filter layer 5 along different paths and directions (opposite to the left). Because the air ejected from the external aeration holes 73 on the left and right sides is in opposite directions, the two mixed air streams aerate and oxygenate the filter media within the filter layer and, when they meet, they again cut with each other, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. At the same time, the air is aerated and oxygenated within the filter layer by continuously changing direction and increasing the oxygen's movement path, further increasing the contact area and path with the filter media, and further enhancing the oxidative degradation of wastewater.

[0033] The main flow of the soda-water mixture formed between each pair of aeration rings continues upward, with the distance between each pair of aeration rings varying continuously from the lowest to the highest point. Below the parting plane, the cross-sectional area between the aeration rings gradually decreases from bottom to top, leaving less room for air flow and gradually increasing the air velocity. This continuously changes the air flow direction, thereby enhancing the air flow effect and the probability of contact with the different surfaces of the polyhedral filter media, effectively improving the aeration and oxygenation effect and enhancing the oxidative degradation of wastewater. When the air reaches the parting plane AA, the cross-sectional area between the two aeration rings is minimized, the air flow velocity reaches its maximum, and the air flow direction further changes, increasing the probability of contact with the different surfaces of the polyhedral filter media.

[0034] Above the aeration ring parting surface, the cross-sectional area between the two aeration rings gradually increases from bottom to top, creating more and more space for air flow. Specifically, the main direction of the air in the middle section is upward, while the main direction of the air in the side sections is diffuse, with the air gradually diffusing to the sides. This strengthens the air flow effect and continuously changes the air flow direction, thereby increasing the probability of contact with different surfaces of the polyhedral filter media, effectively improving the aeration and oxygenation effect, and enhancing the oxidative degradation efficiency of sewage. There are two situations in which air gradually diffuses to the sides: when the aeration ring is strip-shaped, the air gradually diffuses to the sides of the aeration ring; when the aeration ring is spherical, the air gradually diffuses to the periphery of the aeration ring. Below the parting surface of the aeration ring, the cross-sectional area between the two aeration rings gradually decreases from bottom to top, and the air flow space becomes smaller and smaller. Specifically, the mainstream direction of the air in the middle section is upward, while the mainstream direction of the air on the side converges toward the middle. The air gradually converges toward the middle, thereby enhancing the air flow effect and constantly changing the air flow direction, thereby enhancing the contact probability with different surfaces of the polyhedron filter material, effectively improving the aeration and oxygenation effect, and improving the oxidation and degradation efficiency of sewage.

[0035] At the same time, the external aeration holes 73 above the wall cavity parting surface spray air upward and outward at different heights, different radii, and different inclination angles. The angle between the bottom-up spray direction and the horizontal plane gradually increases, and the different surfaces of the filter material in the filter layer are aerated and oxygenated at different inclination angles. The external aeration holes 73 below the wall cavity parting surface spray air downward and outward at different heights, different radii, and different inclination angles. The angle between the bottom-up spray direction and the horizontal plane gradually decreases, and the different surfaces of the filter material in the filter layer are aerated and oxygenated at different inclination angles. This increases the probability of contact with the filter material surfaces at different inclinations, aerating and oxygenating the filter material surfaces at different heights in the filter layer at different inclination angles, thereby oxidizing and degrading the sewage. The second airflow diffusing laterally between each two aeration rings and the first airflow sprayed upward at an angle from the external aeration holes 73 have different flow directions, so when the two airflows meet, they fiercely cut each other, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. At different heights, due to the arc-shaped wall cavity, the radius range of the first airflow injection is different. Therefore, the flow direction of the mixed airflow after cutting each other at different heights also changes continuously, which increases the probability of contact with the filter material surface in different inclination states, transfers more oxygen to the water, and effectively improves the oxygen transfer efficiency.

[0036] Because the filter media is a polyhedron, the mixed airflow, after repeated mixing and cutting, continuously changes its direction, thereby increasing the contact area and path between the sewage and the filter media. This continuously balances the contact effect with the filter media, further increasing the chances of pollutants in the sewage being retained by the filter media layer, increasing the biodegradation of the sewage attached to the filter media, and increasing the probability of removing dissolved organic matter. The continuously changing direction of the mixed airflow causes the position and angle of more filter media to continuously change, thereby increasing the contact area between the sewage and the filter media, increasing the filter media utilization rate, and improving the chances of pollutants in the sewage being retained by the filter media layer. It also increases the biodegradation of the sewage attached to the filter media and the probability of removing dissolved organic matter.

[0037] like Figure 2 and Figure 4 As shown, inside the aeration ring 7, the second air flow Q1 is sprayed upward through the aeration pipe 4, and at the same time, the first air flow Q2 is sprayed inward at an angle from the inner aeration hole 74. Since the two air flows in different directions, when the two mainstream air meet, they violently collide and cut each other.

[0038] Below the parting surface of the aeration ring 7, on the one hand, the angle between the first airflow, which is sprayed inward from bottom to top, and the horizontal plane gradually decreases. When it reaches the parting surface, the velocity direction is horizontal. After mixing with the second airflow running vertically upward, the velocity direction continues to change. The angle between the velocity direction and the horizontal plane gradually decreases as it goes upward, which increases the probability of contact with the filter material surfaces with different tilt states, transfers more oxygen to the water, and effectively improves the oxygen transfer efficiency. On the other hand, from bottom to top, the cross-sectional area of ​​the aeration ring gradually increases, and the air flow space becomes larger and larger. Specifically, the mainstream direction of the air in the middle section is upward, and the mainstream direction of the air in the side section is diffuse. The air gradually diffuses to the side, thereby strengthening the air flow effect. By constantly changing the air flow direction, the probability of contact with different surfaces of the polyhedral filter material is increased, effectively improving the aeration and oxygenation effect, and improving the oxidative degradation efficiency of sewage.

[0039] Above the parting surface of the aeration ring 7, on the one hand, the angle between the first airflow, which is injected obliquely inward from bottom to top, and the horizontal plane gradually increases. After mixing with the second airflow running vertically upward, the velocity direction continuously changes. The angle between the velocity direction and the horizontal plane gradually increases as it goes upward, increasing the probability of contact with the filter media surfaces with different inclinations, transferring more oxygen to the water and effectively improving the oxygen transfer efficiency. On the other hand, the cross-sectional area of ​​the aeration ring 7 gradually decreases from bottom to top, and the air flow space becomes smaller and smaller. Specifically, the main direction of the air in the middle section is upward, while the main direction of the air in the side sections converges inward. The air gradually converges toward the center, thereby strengthening the air flow effect and continuously changing the air flow direction. This increases the probability of contact with different surfaces of the polyhedral filter media, effectively improving the aeration and oxygenation effect, and enhancing the oxidative degradation efficiency of sewage.

[0040] Within the aeration ring 7, the vertically upward flow of the second airflow generates an aeration volume of Q1, while the obliquely inward injection of the first airflow from the inner aeration holes 74 generates an aeration volume of Q2. Within different radii above and below the parting surface, the first and second airflows, injected in different directions, are thoroughly mixed and cut, continuously changing their flow direction multiple times within the filter media layer 5 within the aeration ring. This increases the contact area between the filter media and oxygen in multiple directions, balances the aeration and oxygen dissolution effects and biodegradation efficiency in all directions, and effectively improves the retention and biodegradation of suspended solids.

[0041] Below and above the parting surface, the first airflow, directed inward and tilted upward, gradually decreases in angle with the horizontal plane. Upon reaching the parting surface, its velocity becomes horizontal, and then increases as it moves upward. The velocity direction of the second airflow, after mixing with the vertically upward airflow, also changes. The angle between the velocity direction and the horizontal plane gradually decreases, reaching its minimum upon reaching the parting surface, and then gradually increases. This increases the probability of contact with the filter media surface at different inclinations, transferring more oxygen to the water and effectively improving oxygen transfer efficiency. Furthermore, the cross-sectional area of ​​the aeration ring gradually increases from bottom to top, increasing the air flow space. The main flow direction of the air at the sides becomes diffuse, with the air gradually spreading outward. Upon reaching the parting surface, the cross-sectional area of ​​the aeration ring reaches its maximum, and then gradually decreases upward, with the air flow space becoming smaller and smaller, causing the air velocity to gradually increase, thus continuously changing the air flow direction. Specifically, the mainstream direction of the air in the middle section is upward, while the mainstream direction of the air in the side section converges inward. The air gradually converges toward the middle, thereby enhancing the air flow effect, thereby enhancing the probability of contact with different surfaces of the polyhedral filter material, effectively improving the oxygen aeration efficiency, thereby increasing the chance of pollutants in the sewage being intercepted by the filter material layer, and increasing the biodegradation conversion attached to the filter material, while increasing the probability of dissolved organic matter being removed.

[0042] The air inside the aeration ring escapes from the top at high speed, and when the second airflow that diffuses to the side above the parting surface between the two adjacent aeration rings meets the first airflow that is sprayed obliquely upward from the outer aeration hole 73, they undergo intense mutual cutting, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. The second airflow that gradually diffuses to the side moves outward and upward along a circular arc. Since the cross-sectional area of ​​the lowest end between the two aeration rings is larger than the cross-sectional area of ​​the top end, coupled with the first airflow sprayed between the outer aeration holes, the aeration volume per unit area at the top end is much larger than the unit aeration volume at the lower end. Therefore, the air speed that diffuses outward from between the two aeration rings is greater than the air speed at the lowest end. The second airflow between the aeration rings collides with the first airflow that escapes from the inside of the aeration rings at high speed, and the two airflows undergo intense cutting and mixing again, once again making the bubbles smaller and denser, thereby improving the oxygen transfer efficiency. At the same time, the mixed airflow constantly changes direction, thereby enhancing the air flow effect and the probability of contact with different surfaces of the polyhedral filter material, effectively improving the aeration and oxygenation efficiency, thereby increasing the chance of pollutants in the sewage being intercepted by the filter material layer, and increasing the biodegradation conversion attached to the filter material, while increasing the probability of dissolved organic matter being removed.

[0043] After a biological aerated filter has been running for a period of time, suspended matter in the sewage will adhere to the surface of the filter media. At this time, the filter needs to be backwashed to flush out the trapped suspended matter and restore the activity of the filter media. The embodiment of the present invention uses a combined backwash of air washing and water washing at different radii, different heights, and different directions. Compared with traditional biological aerated filters, the fluid backwash formed by different heights and different inclination directions in this embodiment, combined with water backwash, greatly enhances the backwash effect and effectively improves the effluent water quality and treatment efficiency.

[0044] The aeration method for the sewage treatment biological aeration filter of the above embodiment includes: Step 1: Open the valve of the sewage inlet pipe 1, close the valve of the backwash inlet pipe 2, and open the water outlet. The sewage enters the tank body through the sewage inlet pipe 1. The sewage moves from bottom to top in the tank body, passing through the filter plate 9, the supporting layer 8 and the filter layer 5 in sequence; open the valve of the air inlet pipe 3, and the first airflow enters the aeration ring 7. The first airflow performs auxiliary aeration and oxygenation on the filter material in the filter layer 5; open the valve of the aeration pipe 4, and the second airflow performs main aeration and oxygenation on the filter material in the filter layer 5; Step 2: After the preset working time, close the sewage inlet pipe 1 and the outlet to backwash the biological aerated filter; Step 3, return to step 1 until aeration stops.

[0045] The above-mentioned aeration method is implemented according to the sewage treatment aeration biological filter of the structure of the above-mentioned embodiment. The aeration biological filter includes a tank body, and a filter plate 9, a supporting layer 8, and a filter material layer 5 arranged in sequence from bottom to top in the tank body, and an aeration ring 7 is located in the filter material layer 5; the top and bottom ends of the aeration ring 7 are both provided with openings, and the end face cross-section of the aeration ring 7 is a circular arc with left-right symmetry; the end face width of the aeration ring 7 below the parting surface of the aeration ring 7 gradually increases from bottom to top; the end face width of the aeration ring 7 above the parting surface of the aeration ring 7 gradually decreases from bottom to top; the wall surface of the aeration ring 7 is provided with a wall cavity 72, and the bottom surface is provided with a bottom cavity 71, the wall cavity 72 and the bottom cavity 71 are connected to each other, and the bottom cavity 71 is connected to the air inlet pipe 3; the outer wall of the wall cavity 72 is provided with an outer aeration hole 73, and the inner wall is provided with an inner aeration hole 74.

[0046] Preferably, in step 1, the valve of the air inlet pipe 3 is opened, and the first airflow enters the aeration ring 7, and the first airflow performs auxiliary aeration and oxygenation on the filter material in the filter layer 5; the valve of the aeration pipe 4 is opened, and the second airflow performs main aeration and oxygenation on the filter material in the filter layer 5, including: On the one hand, in the inner cavity of the aeration ring 7, from bottom to top, the angle between the first airflow sprayed inwardly by the inner aeration hole 74 and the horizontal plane gradually decreases. When it reaches the parting surface, the speed direction of the first airflow is horizontal. Then, upward, the angle between the first airflow and the horizontal plane gradually increases. The first airflow assists in aeration and oxygenation of the filter material in the filter layer 5 from different angles.

[0047] On the other hand, in the inner cavity of the aeration ring 7, after the first airflow obliquely ejected inward from the inner aeration hole 74 is mixed with the second airflow vertically ejected upward from the aeration pipe 4, the velocity direction of the mixed airflow continuously changes, and the angle between the velocity direction and the horizontal plane gradually decreases. When it reaches the parting surface, the angle is the smallest, and then gradually increases, so that the mixed airflow and the filter material with different inclination angles are aerated and oxygenated.

[0048] In this method, in the inner cavity of the aeration ring 7, the first airflow, and the airflow obtained by mixing the first and second airflows, continuously change the direction of the airflow velocity, thereby increasing the probability of the airflow contacting the filter material surfaces at different inclination angles, thereby improving the aeration and oxygenation of the filter material.

[0049] Preferably, in step 1, the valve of the air inlet pipe 3 is opened, and the first airflow enters the aeration ring 7, and the first airflow performs auxiliary aeration and oxygenation on the filter material in the filter layer 5; the valve of the aeration pipe 4 is opened, and the second airflow performs main aeration and oxygenation on the filter material in the filter layer 5, further comprising: Below the parting surface on the outside of the aeration ring 7, the vertically upward second airflow ejected from the aeration pipe 4 aerates and oxygenates the vertical surface of the filter material layer 5, then continues to run upward to the outer wall of the aeration ring 7, changes direction and is reflected in the direction away from the aeration ring 7; along the aeration ring 7 from bottom to top, the sum of the incident angle and the reflection angle of the second airflow continues to increase, and the reflected fluid gradually changes from a downward inclination to an upward inclination, thereby aerating and oxygenating the filter materials at different inclination angles.

[0050] like Figure 5 As shown, in this method, below the parting surface of the aeration ring 7, the second airflow is injected into the outer wall of the aeration ring 7 and then reflected, forming a reflected fluid. Because the sidewalls of the aeration ring 7 are curved, the angle α between the incident fluid and the reflected fluid continuously changes from bottom to top along the outer wall of the aeration ring 7. This constantly changing flow direction of the reflected fluid aerates and oxygenates the filter media at different inclined surfaces, thereby increasing the probability of oxygenating the filter media.

[0051] Preferably, in step 1, the valve of the air inlet pipe 3 is opened, and the first airflow enters the aeration ring 7, and the first airflow performs auxiliary aeration and oxygenation on the filter material in the filter layer 5; the valve of the aeration pipe 4 is opened, and the second airflow performs main aeration and oxygenation on the filter material in the filter layer 5, further comprising: Below the outer parting surface of the aeration ring 7, the first airflow is ejected downward and outward at different heights and at different inclination angles through the outer aeration holes 73. From bottom to top, the angle between the ejection direction of the first airflow and the horizontal plane gradually decreases, and different surfaces of the filter material are aerated and oxygenated at different inclination angles. Above the outer parting surface of the aeration ring 7, the first airflow is ejected upward and outward at different heights and different inclination angles through the outer aeration holes 73. From bottom to top, the angle between the ejection direction of the first airflow and the horizontal plane gradually increases, and different surfaces of the filter material are aerated and oxygenated at different inclination angles. On the outside of the aeration ring 7, the second airflow ejected upward by the aeration pipe 4 aerates and oxygenates the filter material in the filter layer 5, thereby oxidizing and degrading the sewage. When the second airflow and the first airflow ejected from the external aeration holes 73 mix, they cut each other, making the bubbles smaller and denser. At different heights, the flow direction of the mixed airflow after cutting each other changes, allowing more oxygen to dissolve in the water, and aeration and oxygenation are carried out in multiple directions in the filter layer 5.

[0052] In this method, the filter media is aerated and oxygenated outside the aeration ring 7 by a second airflow ejected from the aeration tube 4, a first airflow ejected from the external aeration holes 73, and a mixed flow of the second and first airflows ejected from the external aeration holes 73. Simultaneously, the directions of these three airflows continuously change. This constantly shifting flow increases the oxygen's path, providing multi-directional aeration within the filter media layer, further increasing the contact area between air and filter media and enhancing the oxidative degradation of wastewater.

[0053] like Figure 3 As shown, preferably, in the step 1, the valve of the air inlet pipe 3 is opened, and the first airflow enters the aeration ring 7, and the first airflow performs auxiliary aeration and oxygenation on the filter material in the filter layer 5; the valve of the aeration pipe 4 is opened, and the second airflow performs main aeration and oxygenation on the filter material in the filter layer 5, and further comprises: The first airflows ejected from the outer aeration holes 73 on the opposite wall between two adjacent aeration rings 7 meet and cut each other after aerating and oxygenating the filter material to form a mixed airflow, which aerates and oxygenates the filter material in the filter material layer 5; The first airflow ejected from the outer aeration holes 73 on the opposite wall between two adjacent aeration rings 7 and the second airflow ejected vertically upward from the aeration pipe 4 meet and cut each other after aerating and oxygenating the filter material to form a mixed airflow, which aerates and oxygenates the filter material in the filter material layer 5.

[0054] In this method, the mixed airflow is formed by mixing the first airflow injected between two adjacent aeration rings 7, and the mixed airflow is formed by mixing the first airflow injected between two adjacent aeration rings 7 and the second airflow injected from the aeration tube 4. The mixed airflows intersect each other during mixing, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. Simultaneously, the mixed airflow continuously changes direction, increasing the oxygen's path, aerating and oxygenating the filter media layer 5, further increasing the contact area between air and filter media, and further enhancing the oxidative degradation of wastewater.

[0055] In this method, the main flow direction of the soda-water mixture formed between two adjacent aeration rings 7 continues upward. Below the parting surface of the aeration rings 7, the cross-sectional area between the two adjacent aeration rings 7 gradually decreases from bottom to top, and the air flow space becomes smaller and smaller, causing the air flow rate to gradually increase, thereby continuously changing the air flow direction, thereby strengthening the air flow effect and thus increasing the probability of contact with different surfaces of the polyhedral filter material. When the air reaches the parting surface, the cross-sectional area between the two adjacent aeration rings 7 is minimized, the air flow rate reaches a maximum, and the air flow direction is further changed, further increasing the probability of contact with different surfaces of the polyhedral filter material. Above the parting surface, the air flow space between the two adjacent aeration rings 7 becomes increasingly larger, and the air gradually diffuses laterally, thereby strengthening the air flow effect and continuously changing the air flow direction, thereby increasing the probability of contact with different surfaces of the polyhedral filter material.

[0056] The outer aeration holes 73 of two adjacent aeration rings 7 inject air at different heights and angles, aerating and oxygenating different surfaces of the filter media at different heights within the filter layer at varying angles, thereby increasing the contact area with the filter media at varying inclinations. The second airflow, diffused laterally between the two adjacent aeration rings 7, interacts with the first airflow injected at an angle from the outer aeration holes 73, creating a fierce interaction. This creates smaller and denser bubbles, allowing more oxygen to dissolve in the water. The radial range of the airflow varies at different heights, resulting in a continuously changing flow direction after the interaction, increasing the contact area with the filter media at varying inclinations.

[0057] After the biological aeration filter has been operating for a period of time, the sewage inlet pipe 1 and the outlet are closed, and the biological aeration filter is backwashed to flush the suspended matter on the surface of the filter material and restore its working performance. Preferably, in the step 2, the biological aeration filter is backwashed, including: introducing air into the air inlet pipe 3 and the aeration pipe 4; closing the sewage inlet pipe 1. Between the aeration rings 7, the second airflow ejected vertically upward by the aeration pipe 4 and the first airflow ejected from the outer aeration hole 73 of the aeration ring are used for a combined backwashing of air to flush the filter material located on the outside of the aeration ring 7, loosening the filter material layer and separating the suspended matter on the filter material surface from the filter material; in the inner cavity of the aeration ring 7, the second airflow ejected vertically upward by the aeration pipe 4 and the first airflow ejected from the inner aeration hole 74 of the aeration ring are used for a combined backwashing of air to flush the filter material located in the inner cavity of the aeration ring 7, loosening the filter material layer 5 and separating the suspended matter on the filter material surface from the filter material.

[0058] In this method, air is introduced into the air inlet pipe 3 and the aeration pipe 4. The airflow exits the aeration pipe 4, forming a secondary airflow. The airflow exits the aeration ring 7, forming a primary airflow. The filter media is flushed using the primary airflow, the secondary airflow, and the mixed airflow formed by the combination of the primary and secondary airflows, loosening the media and removing suspended matter from its surface. The flushing is primarily performed by backwashing the secondary airflow, which flows upward from the aeration pipe 4, supplemented by backwashing the primary airflow, which is injected at varying heights and angles.

[0059] In this method, inside the aeration ring 7, an upwardly injected second airflow and an obliquely injected first airflow perform a combined backwash. Backwashing is primarily performed by the second airflow, injected from the aeration tube 4 and flowing upward from below, supplemented by backwashing from the first airflow, injected at different heights and angles. Outside the aeration ring 7, the upwardly injected second airflow, the obliquely injected first airflow at different heights and directions, and the newly formed mixed airflow formed by the combination of the first and second airflows, flush suspended matter adhering to the filter media. When the contact surface of the filter media is in an inclined state, the obliquely injected airflow easily washes away the inclined suspended matter, effectively enhancing the effectiveness of the subsequent combined air-water backwash. This overcomes the difficulty of flushing suspended matter adhering to the inclined filter media during the prior art, which utilizes air washing from below to above. The interaction between the first and second airflows continuously alters the air's path and direction, increasing the effectiveness of backwashing at the filter media's contact surfaces at different angles. This loosens the filter media layer, continuously shifts the position and angle of the filter media, and allows more adhering suspended matter to escape, improving the effectiveness of the subsequent combined air-water backwash.

[0060] Preferably, in step 2, backwashing the biological aerated filter further includes: performing a combined air-water backwash. The combined air-water backwashing includes: opening the backwash inlet pipe 2 and the outlet, introducing clean water into the backwash inlet pipe 2, and allowing the clean water to flow upward from the bottom after entering the tank body to flush the surface of the filter material, carrying the suspended matter that has been separated from the filter material surface after air washing upward, leaving the filter material layer 5, and flowing out from the outlet; during this process, air is kept flowing into the air inlet pipe 3 and the aeration pipe 4.

[0061] This method uses combined air and water backwashing. After entering the tank, clean water flows upward from the bottom, flushing the filter media surface. It also carries suspended matter that has been removed from the filter media surface upward, leaving the filter media layer and flowing out through the outlet. As the clean water flows, both the primary and secondary airflows simultaneously flush the filter media surface. This combined air and water flow significantly enhances the backwashing effect.

[0062] Preferably, the air-water combined backwashing further comprises: stopping the introduction of air into the air inlet pipe 3 and the aeration pipe 4, and continuing to introduce clean water into the backwash water inlet pipe 2 to flush the suspended matter out of the tank. This method utilizes water washing to flush the suspended matter that has been detached from the surface of the filter material out of the tank through the water flow.

[0063] In the above-mentioned embodiment or preferred example, the second airflow running upward is reflected by the outer wall of the aeration ring 7 and changes direction to form a reflective fluid, which aerates and oxygenates the filter material in the filter layer, and oxidatively degrades the sewage. From the bottom of the outer wall of the aeration ring 7 to the parting surface of the aeration ring 7, the sum of the incident angle and the reflection angle α of the second airflow continuously increases, so that the direction of the reflective fluid continuously changes, and aeration and oxygenation are performed on the different inclined surfaces of the filter material, thereby increasing the probability of oxygenating the filter material. The reflective fluid gradually changes from being inclined downward to being inclined upward. At different heights, countless streams of reflective fluid in different directions in the circumferential direction increase the probability of contact with the filter material surface at different inclination angles. Therefore, the probability of aerating and oxygenating the filter material at different inclination angles is increased, effectively improving the oxidative degradation efficiency.

[0064] If the aeration ring 7 is spherical, the upward-flowing second airflow changes direction at a certain height and is reflected circumferentially, obliquely downward / upward. On the same horizontal circle, the angles between the reflected airflow and the vertical are equal. That is, each reflected fluid moves downward / upward and outward around the center of the horizontal circle, with each fluid making equal angles with the vertical. On horizontal circles of different diameters, however, the angles between the reflected airflow and the vertical are unequal. On any given plane, the angle between the reflected fluid flowing upward from bottom to top and the vertical continuously increases, gradually shifting from a downward tilt to an upward tilt, causing the reflected fluid's direction to continuously change (whereas on any given horizontal circle, the angle between the reflected airflow and the vertical is equal). This gradual shift from a downward tilt to an upward tilt creates numerous streams of reflected fluid in different directions, increasing the probability of contact with the filter media surface at different angles. This increases the probability of aeration and oxygenation of the filter media at different angles, effectively enhancing oxidative degradation efficiency. Consequently, on the outer surface of the same plane, the angle of the reflected fluid continuously changes circumferentially from the bottom to the parting surface. The plane position of the reflective fluid at the intersection of the outer surface of the spherical segment (in the Y direction) and any horizontal circle is constantly changing, causing the reflective fluid formed by the spherical cavity to assume a spatial state. Because the vast majority of the filter media is tilted at different angles, the reflective fluid at different angles and heights in the circumferential direction provides three-dimensional spatial oxygenation to the filter media at different tilt angles, greatly increasing the contact area for aeration and oxygenation of the filter media and improving the oxidative degradation of wastewater.

[0065] If the aeration ring 7 is strip-shaped, below the parting surface on the left side of the aeration ring 7, the upward-flowing second airflow changes direction at a certain height and is then reflected obliquely downward / upward in the X direction (the length of the tank body). The angle between the reflected fluid and the vertical line increases continuously, and gradually changes from a downward angle to an upward angle, causing the direction of the reflected fluid to continuously change. The reflected fluid gradually changes from a downward angle to an upward angle. The countless streams of reflected fluid in different directions increase the probability of contact with the filter media surface at different inclination angles. This increases the probability of aerating and oxygenating the filter media at different inclination angles, effectively improving the oxidative degradation efficiency. Therefore, on the outer surface of the same positive plane, from the bottom to the parting surface, the angle of the reflected fluid continuously changes. Furthermore, the planar position of the reflected fluid on the outer surface of different positive planes in the Y direction (the width of the tank body) of the wall cavity also continuously changes, causing the reflected fluid formed in the wall cavity to assume a spatial state. Since most of the filter media are in an inclined state at different angles, the reflected fluids at different angles in the circumferential direction perform three-dimensional spatial oxygenation on the filter media at different inclined angles, which greatly increases the contact area for aeration and oxygenation of the filter media and improves the efficiency of oxidative degradation of sewage.

[0066] The second airflow reflected from the two opposite side walls between the aeration rings has opposite directions, thereby greatly increasing the contact area of ​​the filter material for aeration and oxygenation, and improving the efficiency of oxidative degradation of sewage.

[0067] In the sewage treatment biological aeration filter of this embodiment, the first airflows, ejected at different angles from the inner aeration holes and outer aeration holes at different heights and directions above and below the parting surface inside the aeration ring, interact with the second airflow ejected vertically upward from the aeration pipe 4 to adjust the flow paths of the airflow and sewage, the inclination angle and position of the filter material, and improve the oxygen transfer efficiency. At the same time, different surfaces of the filter material are fully exposed to oxygen, improving the utilization rate of the filter material and the oxidative degradation effect on the sewage. The second airflow, ejected from bottom to top through the aeration pipe between the aeration rings, interacts with the first airflow ejected through the outer aeration holes of the aeration rings to adjust the flow paths of air and sewage, the inclination angle and position of the filter material, and improve the oxygen transfer efficiency. Different surfaces of the filter material are fully exposed to oxygen, improving the utilization rate of the filter material, and improving the oxidative degradation effect on the sewage, thereby extending the backwash interval. During backwashing, the first airflows at different heights, radii, and inclinations and the second airflow in the vertical direction backwash the filter material from multiple directions, constantly changing the position and inclination angle of the filter material, increasing the contact area between the air and the filter material, and enhancing the backwashing effect.

[0068] The basic principles, main features, and advantages of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are intended only to further illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the invention as claimed.

Claims

1. A biological aeration filter for sewage treatment, characterized in that: The aerated biological filter comprises a tank body, and a filter plate (9), a supporting layer (8), a filter material layer (5) and an aeration ring (7) arranged in the tank body, wherein the filter plate (9) is located at the lower part of the tank body and is fixedly connected to the inner wall of the tank body, the supporting layer (8) is laid above the filter plate (9), the filter material layer (5) is laid above the supporting layer (8), and the aeration ring (7) is located in the filter material layer (5); a pipe gallery (10) is formed below the filter plate (9), and a water purification zone (6) is formed above the filter material layer (5); a sewage inlet pipe (1), a backwash inlet pipe (2) and an air inlet pipe (3) are provided on the side wall of the pipe gallery (10), and a water outlet is provided on the side wall of the water purification zone (6); an aeration pipe (4) is provided in the supporting layer (8); The top and bottom ends of the aeration ring (7) are both provided with openings, and the end face cross-section of the aeration ring (7) is in the shape of a bilaterally symmetrical circular arc; the width of the end face of the aeration ring (7) gradually increases from bottom to top in the portion below the parting surface of the aeration ring (7); the width of the end face of the aeration ring (7) gradually decreases from bottom to top in the portion above the parting surface of the aeration ring (7); the wall surface of the aeration ring (7) is provided with a wall cavity (72), and the bottom surface is provided with a bottom cavity (71); the wall cavity (72) and the bottom cavity (71) are communicated with each other, and the bottom cavity (71) is communicated with the air inlet pipe (3); the outer wall of the wall cavity (72) is provided with an outer aeration hole (73), and the inner wall is provided with an inner aeration hole (74).

2. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The aeration pipes (4) are interconnected and arranged in parallel in the horizontal direction; and single-hole membrane air diffusers are evenly arranged on the aeration pipes (4).

3. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The top of the aeration ring (7) is 500 to 1500 mm higher than the top of the supporting layer (8).

4. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The aeration ring (7) is in the shape of a strip, and the axis of the aeration ring (7) is perpendicular to the length direction of the tank body; or, the aeration ring (7) is in the shape of a spherical segment.

5. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The bottom cavity (71) is an annular cavity.

6. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The top opening area of ​​the aeration ring (7) is larger than the bottom opening area.

7. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The axis of the inner aeration hole (74) intersects with the axis of the aeration ring (7); the axis of the outer aeration hole (73) intersects with the axis of the aeration ring.

8. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The inner aeration holes (74) are evenly distributed on the inner wall of the aeration ring (7), and the outer aeration holes (73) are evenly distributed on the outer wall of the aeration ring (7). The pore diameters of the inner aeration holes (74) and the outer aeration holes (73) are both 80 to 120 μm.

9. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The aeration volume of the top opening of the aeration ring (7) is equal to aQ1S 上 / S 下 , where Q1 represents the aeration volume of the aeration tube (4) in the inner cavity of the aeration ring (7), S 上 represents the top opening area of ​​the aeration ring (7), S 下 represents the bottom opening area of ​​the aeration ring (7), a represents the adjustment coefficient, and the value range of a is 1.1 to 1.

3.

10. The biological aeration filter for sewage treatment according to claim 1, characterized in that: The sum of the aeration volume of the inner aeration holes (74) and the outer aeration holes (73) of the aeration ring (7) is equal to 10-30% of the aeration volume of the aeration pipe (4).

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