Aeration method for a wastewater treatment biological aerated filter

Abstract

This invention belongs to the field of wastewater treatment and discloses an aeration method for an aerated biological filter for wastewater treatment. This method continuously changes the direction and path of oxygen flow, improving oxygen transfer efficiency and filter media utilization, thereby effectively improving wastewater treatment efficiency. The aeration method includes: Step 1: Opening the valve of the wastewater inlet pipe, closing the valve of the backwash inlet pipe, and opening the outlet. Wastewater enters the filter body through the wastewater inlet pipe and moves upwards within the filter body, passing sequentially through the filter plate, support layer, and filter media layer. Opening the valve of the air inlet pipe allows the first airflow to enter the aeration ring, providing auxiliary aeration and oxygenation to the filter media in the filter media layer. Opening the valve of the aeration pipe allows the second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer. Step 2: After a preset working time, closing the wastewater inlet pipe and outlet, and backwashing the aerated biological filter. Step 3: Returning to Step 1 until aeration stops.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an aeration method for an aerated biological filter in wastewater treatment. Background Technology

[0002] Wastewater treatment aerated biological filters integrate filtration and biological adsorption, offering advantages such as excellent filtration and adsorption, high treatment efficiency, and good effluent quality. Oxygen supplied by the aeration pipes rises from the bottom to the filter media layer, while wastewater passes through the layer from the bottom up, where the filter media oxidizes and degrades the wastewater. However, the oxygen's path is fixed upwards, and much of the filter media is tilted, preventing sufficient contact between the multifaceted media and oxygen, thus reducing media utilization. Furthermore, some filter media within the layer are not fully oxidized and degraded before backwashing, shortening the backwashing interval and reducing production efficiency. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide an aeration method for an aerated biological filter for wastewater treatment, which continuously changes the direction and path of oxygen flow, so that the polyhedral filter media can fully contact oxygen in multiple directions, thereby improving the oxygen transfer efficiency and the utilization rate of the filter media, enhancing the oxidative degradation effect on wastewater, and effectively improving the wastewater treatment efficiency.

[0004] To solve the above-mentioned technical problems, embodiments of the present invention provide an aeration method for an aerated biological filter in wastewater treatment, comprising:

[0005] Step 1: Open the valve of the sewage inlet pipe, close the valve of the backwash inlet pipe, and open the outlet. Sewage enters the tank through the sewage inlet pipe and moves from bottom to top in the tank, passing through the filter plate, support layer, and filter media layer in sequence. Open the valve of the air inlet pipe, and the first airflow enters the aeration ring. The first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer. Open the valve of the aeration pipe, and the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer.

[0006] Step 2: After the preset working time, close the sewage inlet and outlet pipes and backwash the aerated biological filter.

[0007] Step 3: Return to Step 1 until aeration stops.

[0008] As a preferred example, the aerated biological filter includes a tank body and filter plates, a support layer, and a filter media layer arranged sequentially from bottom to top within the tank body, with an aeration ring located in the filter media layer; the top and bottom ends of the aeration ring are provided with openings, and the end face cross-section of the aeration ring is symmetrically arc-shaped; below the parting surface of the aeration ring, the width of the end face of the aeration ring gradually increases from bottom to top; above the parting surface of the aeration ring, the width of the end face of the aeration ring 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 interconnected, and the bottom cavity is connected to the air inlet pipe; the outer wall of the wall cavity is provided with external aeration holes, and the inner wall is provided with internal aeration holes.

[0009] As a preferred example, opening the valve of the air inlet pipe allows a first airflow to enter the aeration ring, providing auxiliary aeration and oxygenation to the filter media in the filter media layer; opening the valve of the aeration pipe allows a second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer, including:

[0010] In the inner cavity of the aeration ring, from bottom to top, the angle between the first airflow, which is sprayed inward at an angle from the inner aeration hole, and the horizontal plane gradually decreases. When it reaches the parting surface, the velocity direction of the first airflow is horizontal. Then, as it moves upward, the angle between the first airflow and the horizontal plane gradually increases. The first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer from different angles.

[0011] In the inner cavity of the aeration ring, the first airflow, which is injected inward at an angle, mixes with the second airflow, which is injected vertically upward from the aeration pipe. The velocity direction of the mixed airflow changes continuously. The angle between the velocity direction and the horizontal plane gradually decreases first, and reaches its minimum when it reaches the parting surface. Then it gradually increases, so that the mixed airflow aerates and oxygenates the filter media with different tilt angles.

[0012] As a preferred example, when the valve of the air inlet pipe is opened, the first airflow enters the aeration ring, and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer; when the valve of the aeration pipe is opened, the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer, including: below the parting surface on the outer side of the aeration ring, the vertically upward second airflow ejected from the aeration pipe aerates and oxygenates the vertical surface in the filter media layer, and then continues to move upward to the outer wall of the aeration ring, changes direction, and is reflected away from the aeration ring; along the aeration ring from bottom to top, the sum of the incident angle and the reflection angle of the second airflow continuously increases, and the reflected fluid gradually changes from inclined downward to inclined upward, aerating and oxygenating the filter media at different inclination angles.

[0013] As a preferred example, when the valve of the air inlet pipe is opened, the first airflow enters the aeration ring and provides auxiliary aeration and oxygenation to the filter media in the filter media layer; when the valve of the aeration pipe is opened, the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer, including: below the parting surface on the outer side of the aeration ring, the first airflow is sprayed downward and outward through the external aeration holes at different heights and different inclination angles, from bottom to top, the angle between the spray direction of the first airflow and the horizontal plane gradually decreases, and different surfaces of the filter media are aerated and oxygenated at different inclination angles downward.

[0014] Above the outer parting surface of the aeration ring, the first airflow is sprayed upward and outward through the external aeration holes at different heights and at different tilt angles. From bottom to top, the angle between the direction of the first airflow and the horizontal plane gradually increases, and different surfaces of the filter material are aerated and oxygenated at different tilt angles.

[0015] Outside the aeration ring, the second airflow, sprayed upwards from the aeration pipe, aerates and oxygenates the filter media in the filter media layer, and oxidizes and degrades the wastewater. When the second airflow mixes with the first airflow sprayed from the external aeration holes, 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 aerating and oxygenating the filter media layer in multiple directions.

[0016] As a preferred example, when the valve of the air inlet pipe is opened, the first airflow enters the aeration ring and provides auxiliary aeration and oxygenation to the filter media in the filter media layer; when the valve of the aeration pipe is opened, the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer, including: the first airflows sprayed from the outer aeration holes on the opposing walls between two adjacent aeration rings meet and cut each other after aerating and oxygenating the filter media, forming a mixed airflow, which aerates and oxygenates the filter media in the filter media layer;

[0017] The first airflow injected from the external aeration holes on the opposing wall surfaces between two adjacent aeration rings, and the second airflow ejected vertically upward from the aeration pipe, meet and cut each other after aerating and oxygenating the filter media, forming a mixed airflow that aerates and oxygenates the filter media layer.

[0018] As a preferred example, step 2, backwashing the aerated biological filter, includes:

[0019] Air is introduced into the air intake pipe and the aeration pipe;

[0020] Between the aeration rings, the second airflow injected vertically upward from the aeration pipe and the first airflow injected from the outer aeration holes of the aeration ring perform a combined backwashing, washing the filter media located outside the aeration ring, loosening the filter media layer, and removing suspended matter from the surface of the filter media.

[0021] In the inner cavity of the aeration ring, the second airflow injected vertically upward from the aeration pipe and the first airflow injected from the inner aeration holes of the aeration ring perform a combined backwashing, washing the filter media located in the inner cavity of the aeration ring, loosening the filter media layer, and causing suspended matter on the surface of the filter media to detach from the filter media.

[0022] As a preferred example, step 2, which involves backwashing the aerated biological filter, further includes performing a combined air-water backwash.

[0023] As a preferred example, the combined air-water backwashing includes: opening the backwash inlet pipe, introducing clean water into the backwash inlet pipe, and the clean water moving upwards after entering the tank to wash the surface of the filter media. The suspended matter that has been separated from the filter media surface by air washes moves upwards, leaves the filter media layer, and flows out from the outlet. During this process, air is continuously introduced into the air inlet pipe and the aeration pipe.

[0024] As a preferred example, the combined steam and water backwashing further includes: stopping the introduction of air into the air inlet pipe and the aeration pipe, and continuing to introduce clean water into the backwash water inlet pipe to flush the suspended solids out of the pool.

[0025] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The aeration method of the wastewater treatment aerated biological filter of the present invention continuously changes the direction and path of oxygen flow, so that the multifaceted filter media and oxygen are fully in contact in multiple directions, improving the oxygen transfer efficiency and the utilization rate of the filter media, improving the oxidation and degradation effect on wastewater, and effectively improving the wastewater treatment efficiency. The aeration method includes: Step 1, opening the valve of the wastewater inlet pipe, closing the valve of the backwash inlet pipe, opening the outlet, and the wastewater enters the tank through the wastewater inlet pipe. The wastewater moves from bottom to top in the tank, passing through the filter plate, the support layer and the filter media layer in sequence; opening the valve of the air inlet pipe, the first airflow enters the aeration ring, and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer; opening the valve of the aeration pipe, the second airflow provides main aeration and oxygenation to the filter media in the filter media layer; Step 2, after the preset working time, closing the wastewater inlet pipe and the outlet, and backwashing the aerated biological filter; Step 3, returning to Step 1 until aeration stops. The first airflow is used to assist in aeration and oxygenation of the filter media in the filter media layer, while the second airflow is used for primary aeration and oxygenation of the filter media in the filter media layer. The airflow path is continuously changed to improve the oxygen transfer efficiency, so that different surfaces of the filter media can fully contact oxygen, thereby improving the utilization rate of the filter media, improving the oxidation and degradation effect on wastewater, and extending the backwashing interval. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the aerated biological filter in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the aeration ring structure in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the aeration effect between the aeration rings in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the aeration effect inside the aeration ring in an embodiment of the present invention:

[0030] Figure 5 This is a schematic diagram of the reflected fluid on the outer wall of the aeration ring in an embodiment of the present invention;

[0031] Figure 6 This is a diagram showing the arrangement of an aeration ring in an embodiment of the present invention.

[0032] The diagram includes: 1. Sewage inlet pipe, 2. Backwash inlet pipe, 3. Air inlet pipe, 4. Aeration pipe, 5. Filter media layer, 6. Clean water zone, 7. Aeration ring, 7. Bottom cavity, 71. Wall cavity, 72. External aeration hole, 73. Internal aeration hole, 74. Support layer, 8. Filter plate, 9. Pipe gallery, and 10. Detailed Implementation

[0033] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] The aeration method for an aerated biological filter in wastewater treatment according to an embodiment of the present invention includes:

[0035] Step 1: Open the valve of the sewage inlet pipe 1, close the valve of the backwash inlet pipe 2, and open the outlet. Sewage enters the tank through the sewage inlet pipe 1 and moves upward in the tank, passing through the filter plate 9, the support layer 8, and the filter media 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 provides auxiliary aeration and oxygenation to the filter media in the filter media layer 5. Open the valve of the aeration pipe 4, and the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer 5.

[0036] Step 2: After the preset working time, close the sewage inlet pipe 1 and the outlet, and backwash the aerated biological filter.

[0037] Step 3: Return to Step 1 until aeration stops.

[0038] The above-described aeration method is implemented in an aerated biological filter for wastewater treatment. The aerated biological filter includes a tank body, and filter plates 9, a support layer 8, and a filter media layer 5 arranged sequentially from bottom to top within the tank body. An aeration ring 7 is located within the filter media layer 5. The aeration ring 7 has openings at both its top and bottom ends, and its end face cross-section is a symmetrical arc shape. Below the parting line of the aeration ring 7, the width of its end face gradually increases from bottom to top; above the parting line, the width of its end face gradually decreases from bottom to top. The aeration ring 7 has a wall cavity 72 on its wall surface and a bottom cavity 71 on its bottom surface. The wall cavity 72 and the bottom cavity 71 are interconnected, and the bottom cavity 71 is connected to the air inlet pipe 3. The outer wall of the wall cavity 72 has external aeration holes 73, and the inner wall has internal aeration holes 74. The specific structure of the aerated biological filter is described in detail below.

[0039] Preferably, in step 1, opening the valve of the air inlet pipe 3 allows the first airflow to enter the aeration ring 7, providing auxiliary aeration and oxygenation to the filter media in the filter media layer 5; opening the valve of the aeration pipe 4 allows the second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer 5, including:

[0040] On the one hand, in the inner cavity of the aeration ring 7, from bottom to top, the angle between the first airflow injected into the inner aeration hole 74 and the horizontal plane gradually decreases. When it reaches the parting surface, the velocity direction of the first airflow is horizontal. Then, upward, the angle between the first airflow and the horizontal plane gradually increases. The first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer 5 from different angles.

[0041] On the other hand, in the inner cavity of the aeration ring 7, after the first airflow injected inward at the inner aeration hole 74 mixes with the second airflow ejected vertically upward from the aeration pipe 4, the velocity direction of the mixed airflow changes continuously. The angle between the velocity direction and the horizontal plane gradually decreases first, and the angle is the smallest when it reaches the parting surface. Then it gradually increases, so that the mixed airflow aerates and oxygenates the filter media with different tilt angles.

[0042] In this method, within the inner cavity of the aeration ring 7, the first airflow and the airflow resulting from the mixture of the first and second airflows continuously change their airflow velocity and direction, thereby increasing the contact probability between the airflow and the filter media surface at different tilt angles, and thus improving the aeration and oxygenation of the filter media.

[0043] Preferably, in step 1, opening the valve of the air inlet pipe 3 allows the first airflow to enter the aeration ring 7, providing auxiliary aeration and oxygenation to the filter media in the filter media layer 5; opening the valve of the aeration pipe 4 allows the second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer 5, further comprising:

[0044] Below the parting surface on the outer side 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 media layer 5, and then continues to run upward to the outer wall of the aeration ring 7. After changing direction, it is reflected 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 continuously increases, and the reflected fluid gradually changes from tilted downward to tilted upward, aerating and oxygenating the filter media at different tilt angles.

[0045] like Figure 5 As shown, in this method, below the parting surface of the aeration ring 7, the second airflow is reflected after being sprayed onto the outer wall of the aeration ring 7, forming a reflecting fluid. Because the sidewall of the aeration ring 7 is arc-shaped, the angle α between the incident fluid and the reflecting fluid continuously changes from bottom to top along the outer wall of the aeration ring 7. The constantly changing flow direction of the reflecting fluid aerates and oxygenates different inclined surfaces of the filter media, thereby increasing the probability of oxygenation of the filter media.

[0046] Preferably, in step 1, opening the valve of the air inlet pipe 3 allows the first airflow to enter the aeration ring 7, providing auxiliary aeration and oxygenation to the filter media in the filter media layer 5; opening the valve of the aeration pipe 4 allows the second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer 5, further comprising:

[0047] Below the outer parting surface of the aeration ring 7, the first airflow is sprayed downward and outward through the external aeration holes 73 at different heights and different tilt angles. From bottom to top, the angle between the direction of the first airflow and the horizontal plane gradually decreases, and different surfaces of the filter material are aerated and oxygenated at different tilt angles downward.

[0048] Above the outer parting surface of the aeration ring 7, the first airflow is sprayed upward and outward through the external aeration holes 73 at different heights and different tilt angles. From bottom to top, the angle between the direction of the first airflow and the horizontal plane gradually increases, and different surfaces of the filter material are aerated and oxygenated at different tilt angles.

[0049] Outside the aeration ring 7, the second airflow sprayed upward from the aeration pipe 4 aerates and oxygenates the filter media in the filter media layer 5, and oxidizes and degrades the wastewater. When the second airflow and the first airflow sprayed from the external aeration hole 73 mix, they cut each other, making the bubbles smaller and denser. At different heights, the flow direction of the mixed airflow after mutual cutting changes, allowing more oxygen to dissolve in the water, and aerating and oxygenating in multiple directions in the filter media layer 5.

[0050] In this method, outside the aeration ring 7, the filter media is aerated by a second airflow injected from the aeration pipe 4, a first airflow injected from the external aeration holes 73, and a mixture of the second airflow and the first airflow injected from the external aeration holes 73. Simultaneously, the flow directions of these three airflows continuously change. This constantly changing flow direction increases the oxygen's movement path, resulting in multi-directional aeration within the filter media layer, further enhancing the contact area between air and the filter media, and improving the oxidative degradation efficiency of wastewater.

[0051] like Figure 3 As shown, preferably, in step 1, opening the valve of the air inlet pipe 3 allows the first airflow to enter the aeration ring 7, providing auxiliary aeration and oxygenation to the filter media in the filter media layer 5; opening the valve of the aeration pipe 4 allows the second airflow to provide primary aeration and oxygenation to the filter media in the filter media layer 5, further comprising:

[0052] The first airflow injected from the external aeration holes 73 on the opposite wall surfaces between two adjacent aeration rings 7 meets and cuts each other after aerating and oxygenating the filter media, forming a mixed airflow that aerates and oxygenates the filter media in the filter media layer 5.

[0053] The first airflow ejected from the external aeration holes 73 on the opposite wall surfaces 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 media, forming a mixed airflow that aerates and oxygenates the filter media in the filter media layer 5.

[0054] In this method, a mixed airflow is formed by mixing the first airflow injected between two adjacent aeration rings 7, and a mixed airflow is formed by mixing the first airflow injected between two adjacent aeration rings 7 and the second airflow injected from the aeration pipe 4. During mixing, the airflows cut each other, 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 movement path and aerating the filter media layer 5, further increasing the contact area between air and the filter media, and further enhancing the oxidative degradation effect on wastewater.

[0055] In this method, the mainstream direction of the air-water mixture formed between two adjacent aeration rings 7 continues upward. Below the parting surface of the aeration rings 7, from bottom to top, the cross-sectional area between two adjacent aeration rings 7 gradually decreases, the airflow space becomes smaller, and the airflow velocity gradually increases, continuously changing the airflow direction and thus enhancing the airflow effect. This, in turn, increases the probability of contact with different surfaces of the polyhedral filter media. When the air reaches the parting surface, the cross-sectional area between two adjacent aeration rings 7 is at its minimum, the airflow velocity reaches its maximum, and the airflow direction is further changed, further enhancing the probability of contact with different surfaces of the polyhedral filter media. Above the parting surface, the airflow space between two adjacent aeration rings 7 becomes larger, and the air gradually diffuses to the side, thereby enhancing the airflow effect and continuously changing the airflow direction, thus increasing the probability of contact with different surfaces of the polyhedral filter media.

[0056] Air is injected from the outer aeration holes 73 of adjacent aeration rings 7 at different heights and tilt angles, aerating and oxygenating different surfaces of the filter media at different heights and tilt angles, thus increasing the contact area with the filter media surfaces at different tilt positions. When the second airflow diffusing laterally between adjacent aeration rings 7 meets the first airflow injected at an angle from the outer aeration holes 73, they undergo intense mutual cutting, making the bubbles smaller and denser, and allowing more oxygen to dissolve in the water. The injection radius varies at different heights, thus the flow direction of the air after mutual cutting at different heights constantly changes, further increasing the contact area with the filter media surfaces at different tilt positions.

[0057] After the aerated biological filter has been operating for a period of time, the wastewater inlet pipe 1 and outlet are closed, and the aerated biological filter is backwashed to flush away suspended solids on the surface of the filter media, restoring its working performance. Preferably, in step 2, the backwashing of the aerated biological filter includes: introducing air into the air inlet pipe 3 and aeration pipe 4; and closing the wastewater inlet pipe 1. Between the aeration rings 7, a combined backwashing of air occurs between the second airflow vertically upward from the aeration pipe 4 and the first airflow from the outer aeration holes 73 of the aeration ring, flushing the filter media located outside the aeration rings 7, loosening the filter media layer, and removing suspended solids from the filter media surface; inside the aeration rings 7, a combined backwashing of air occurs between the second airflow vertically upward from the aeration pipe 4 and the first airflow from the inner aeration holes 74 of the aeration ring, flushing the filter media located inside the aeration rings 7, loosening the filter media layer 5, and removing suspended solids from the filter media surface.

[0058] In this method, air is introduced into the air inlet pipe 3 and the aeration pipe 4. Airflow exits from the aeration pipe 4, forming a second airflow. Airflow exits from the aeration ring 7, forming a first airflow. The filter media is washed using the first airflow, the second airflow, and the mixed airflow formed by their combination, causing the filter media to loosen and detach suspended matter from its surface. The backwashing is primarily performed using the upward-flowing second airflow injected from the aeration pipe 4, supplemented by the backwashing of the first airflow injected at different heights and angles.

[0059] In this method, inside the aeration ring 7, an upward-spraying second airflow and an inclined-spraying first airflow perform combined backwashing. The backwashing is primarily performed using the upward-flowing second airflow from the aeration pipe 4, supplemented by the backwashing from the inclined first airflow at different heights and angles. Outside the aeration ring 7, the upward-spraying second airflow, the inclined first airflow at different heights and directions, and the newly formed mixed airflow from the first and second airflows wash away suspended matter adhering to the filter media. When the contact surface of the filter media is inclined, the inclined airflow easily washes away the inclined suspended matter, effectively improving the subsequent combined air-water backwashing effect. This overcomes the difficulty in cleaning the suspended matter adhering to the inclined filter media during bottom-up air washing in existing technologies, thus improving the backwashing effect. The interaction of the first and second airflows continuously changes the air's movement path and direction, increasing the backwashing effect on the contact surfaces of the filter media at different inclination angles. This loosens the filter media layer, causing the position and angle of the filter media to continuously change, allowing more adhered suspended matter to detach from the filter media, thus improving the subsequent combined air-water backwashing effect.

[0060] Preferably, in step 2, backwashing the aerated biological filter further includes performing combined air-water backwashing. This combined air-water backwashing includes: opening the backwash inlet pipe 2 and the outlet, introducing clean water into the backwash inlet pipe 2, allowing the clean water to flow upwards into the filter media, washing the surface of the filter media, and carrying suspended solids that have detached from the filter media surface after air washing upwards, leaving the filter media layer 5 and flowing out from the outlet; during this process, air is continuously introduced into the air inlet pipe 3 and the aeration pipe 4.

[0061] This method employs a combined air-water backwashing process. After entering the tank, the clean water moves upwards, washing the filter media surface while simultaneously carrying suspended solids that have detached from the filter media surface after being washed by the air. These solids then flow upwards from the filter media layer and exit through the outlet. During the water flow, both the first and second airflows simultaneously wash the filter media surface. This combined air-water action significantly improves the backwashing effect.

[0062] Preferably, the combined air-water backwashing further includes: 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 solids out of the tank. This method utilizes water washing to flush the suspended solids that have detached from the filter media surface out of the tank through water flow.

[0063] In the above embodiments or preferred embodiments, the upward-moving second airflow changes direction after being reflected by the outer wall of the aeration ring 7, forming a reflective fluid that aerates and oxygenates the filter media in the filter media layer, thereby oxidizing and degrading the wastewater. From the bottom of the outer wall of the aeration ring 7 towards 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, causing the direction of the reflective fluid to continuously change, aerating and oxygenating different inclined surfaces of the filter media, thus increasing the probability of oxygenation of the filter media. The reflective fluid gradually changes from inclined downwards to inclined upwards, and at different heights, countless reflective fluids in different directions along the circumference increase the probability of contact with the filter media surfaces at different inclination angles. Therefore, the probability of aeration and oxygenation of the filter media at different inclination angles is increased, effectively improving the oxidative degradation efficiency.

[0064] If the aeration ring 7 is a spherical cap, the upward-moving second airflow changes direction at a certain height and is reflected downwards / upwards in the circumferential direction. On the same horizontal circle, the angle between the reflected airflow and the vertical line is equal in the circumferential direction, meaning that each reflecting fluid moves downwards / upwards and outwards around the center of the horizontal circle, and the angle between each fluid and the vertical direction is equal. However, on horizontal circles of different diameters, the angle between the reflected airflow and the vertical line is not equal. On any plane, the angle between the upward-moving reflecting fluid and the vertical line continuously increases, and gradually changes from downwards to upwards, causing the direction of the reflecting fluid to continuously change (while on any horizontal circle of any diameter, the angle between the reflected airflow and the vertical line is equal). The gradual change from downwards to upwards in the reflecting fluid increases the probability of contact between numerous reflecting fluids in different directions and the filter media surface at different tilt angles. Therefore, the probability of aeration and oxygenation of the filter media at different tilt angles is increased, effectively improving the oxidative degradation efficiency. Thus, on the outer surface of the same plane, from the bottom to the parting surface in the circumferential direction, the angle of the reflecting fluid continuously changes. Furthermore, the planar position of the reflective fluid at the intersection of the outer surface of different planes (Y-direction) of the spherical cavity and any horizontal circle is constantly changing, thus making the reflective fluid formed by the spherical cavity spatial. Since most of the filter media are tilted at different angles, the reflective fluid at different heights and angles 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 efficiency of wastewater oxidation and degradation.

[0065] If the aeration ring 7 is strip-shaped, below the parting surface on the left side of the aeration ring 7, the upward-moving second airflow changes direction at a certain height and is reflected downwards / upwards in the X direction (the length direction of the tank). The angle between the upward-moving reflected fluid and the vertical line continuously increases, gradually changing from downwards to upwards, causing the direction of the reflected fluid to constantly change. As the reflected fluid gradually changes from downwards to upwards, numerous reflected fluids in different directions increase the probability of contact with the filter media surfaces at different tilt angles. Therefore, the probability of aeration and oxygenation of the filter media at different tilt angles is increased, effectively improving the oxidative degradation efficiency. Thus, on the outer surface of the same 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 the different Y-directions (the width direction of the tank) of the wall cavity also continuously changes, resulting in a spatial state of the reflected fluid formed in the wall cavity. Since most of the filter media are tilted at different angles, the reflective fluid at different angles in the circumferential direction provides three-dimensional spatial oxygenation to the filter media at different tilt angles, which greatly increases the contact area for aeration and oxygenation of the filter media and improves the efficiency of oxidative degradation of wastewater.

[0066] The second airflow reflected on the opposite side walls between the aeration rings has an opposite direction, which greatly increases the contact area of ​​the filter media for aeration and oxygenation, thus improving the efficiency of oxidative degradation of wastewater.

[0067] In this embodiment of the wastewater treatment aerated biological filter, a first airflow at different angles, injected from inner and outer aeration holes at different heights and directions above and below the parting surface inside the aeration ring, interacts with a vertically upward second airflow injected from aeration pipe 4. This adjusts the flow paths of the airflow and wastewater, as well as the tilt angle and position of the filter media, thereby improving oxygen transfer efficiency. Simultaneously, it ensures sufficient contact between different surfaces of the filter media and oxygen, increasing the utilization rate of the filter media and enhancing the oxidative degradation effect on wastewater. Furthermore, the second airflow, injected from below through aeration pipes between the aeration rings, interacts with the first airflow injected through the outer aeration holes of the aeration rings. This further adjusts the flow paths of the air and wastewater, as well as the tilt angle and position of the filter media, improving oxygen transfer efficiency, ensuring sufficient contact between different surfaces of the filter media and oxygen, increasing the utilization rate of the filter media, enhancing the oxidative degradation effect on wastewater, and extending the backwashing interval. During backwashing, a first airflow at different heights, radii, and inclination directions, along with a second airflow in the vertical direction, backwash the filter media from multiple directions. This continuously changes the position and inclination angle of the filter media, increasing the contact area between the air and the filter media and enhancing the backwashing effect.

[0068] After a period of operation, suspended solids from wastewater will adhere to the surface of the filter media in an aerated biological filter. At this point, backwashing is necessary to remove the trapped suspended solids and restore the filter media's activity. This embodiment of the invention employs a combined backwashing process of air and water washing with varying radii, heights, and directions. Compared to traditional aerated biological filters, this embodiment utilizes fluid backwashing at different heights and inclination directions, combined with water backwashing, significantly enhancing the backwashing effect and effectively improving effluent quality and treatment efficiency.

[0069] The above aeration method is implemented in an aerated biological filter for wastewater treatment. As one example, the specific structure of the aerated biological filter for wastewater treatment is as follows: Figure 1 As shown, the system includes a tank body, and filter plates 9, a support layer 8, a filter media layer 5, and an aeration ring 7 disposed within the tank body. 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 support layer 8 is laid on top of the filter plate 9, the filter media layer 5 is laid on top of 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 side wall of the pipe gallery 10 is provided with a sewage inlet pipe 1, a backwash inlet pipe 2, and an air inlet pipe 3. The side wall of the clean water zone 6 is provided with an outlet. An aeration pipe 4 is provided within the support layer 8. The aeration ring 7 has openings at both its top and bottom ends, and the end face cross-section of the aeration ring 7 is a symmetrical arc shape. Below the parting surface of the aeration ring 7, the width of the end face of the aeration ring 7 gradually increases from bottom to top. The parting surface of the aeration ring 7 is a horizontal plane, and the maximum horizontal width of the aeration ring 7 cross-section is as follows: Figure 2 As shown in section AA, the cross-sectional width of the aeration ring 7 gradually increases from the lowest point to the parting surface, and gradually decreases from the parting surface to the highest point. The aeration ring 7 has a wall cavity 72 on its wall surface and a bottom cavity 71 on its bottom surface. The wall cavity 72 and the bottom cavity 71 are interconnected, and the bottom cavity 71 is connected to the air inlet pipe 3. The outer wall of the wall cavity 72 has external aeration holes 73, and the inner wall has internal aeration holes 74.

[0070] In the above embodiment, when the wastewater treatment aerated biological filter is working, wastewater enters the pipe gallery 10 from the wastewater inlet pipe 1, flowing from bottom to top through the filter plate 9, the support layer 8, and the filter media layer 5. After being filtered and adsorbed by the filter media layer 5, the wastewater becomes clear water and flows out from the outlet of the clean water zone 6. The filter plate 9 mainly serves a supporting function, supporting the aeration ring 7, the support layer 8, and the filter media layer 5 located above it. The support layer 8 mainly serves a supporting and filtering function. The support layer 8 can be made of pebbles with good strength and chemical stability to fix the filter media layer 5. The support layer 8 can filter larger pollutants in the wastewater, such as sand particles. The support layer 8 supports the filter media layer 5 and the aeration ring 7 located above it. The filter media layer 5 mainly serves a filtering and adsorption function. The filter media in the filter media layer 5 is polyhedral, and each filter media is randomly arranged with different positions. The filter media has high porosity, large specific surface area, and strong biological adhesion. An aeration pipe 4 is provided in the support layer 8. The second airflow exiting aeration pipe 4 moves vertically upwards, aerating the filter media. Valves are installed at the inlet ends of wastewater inlet pipe 1 and backwash inlet pipe 2. Regulating valves are installed at the inlet ends of air inlet pipe 3 and aeration pipe 4 to control the amount and pressure of air entering the aerated biological filter. An outlet pipe is located outside the filter body, connected to an outlet. A valve is installed on the outlet pipe to control the opening and closing of the outlet.

[0071] The aeration ring 7 has openings at both its top and bottom. Both the inner cavity and the outer surface of the aeration ring are filled with filter media. A portion of the second airflow flowing from the aeration pipe 4 enters the inner cavity of the aeration ring 7 through the bottom opening and exits through the top opening, oxidizing and degrading the wastewater in the filter media layer within the aeration ring 7. This aeration rate is Q1. The remaining portion of the second airflow flows outside the aeration ring 7. The outer aeration holes 73 of the aeration ring inject the first airflow outwards, while the inner aeration holes 74 inject the first airflow into the inner cavity. The first airflow serves as auxiliary oxygenation (aeration from different directions), while the second airflow serves as primary oxygenation.

[0072] In the above embodiment, the end face cross-section of the aeration ring 7 is a symmetrical arc shape. Below the parting surface, the width of the end face of the aeration ring 7 gradually increases from bottom to top. Above the parting surface, the width of the end face 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, resulting in a larger internal airflow space. The mainstream airflow direction on the sides (for strip-shaped aeration rings, the sides are both sides; for spherical aeration rings, the sides are all around) is diffused, with air gradually diffusing to the sides. When it reaches the parting surface, the cross-sectional area is at its maximum. Further upwards, the cross-sectional area of ​​the aeration ring gradually decreases, resulting in a smaller airflow space and a gradual increase in air velocity, continuously changing the airflow direction. The mainstream airflow direction on the sides converges inwards, gradually converging towards the center, thereby enhancing the airflow effect and increasing the contact probability with different surfaces of the polyhedral filter media.

[0073] Preferably, the aeration pipes 4 are interconnected and arranged parallel to each other in the horizontal direction; single-pore membrane air diffusers are evenly distributed on the aeration pipes 4. This ensures a uniform pressure distribution of the second airflow emitted by each single-pore membrane air diffuser on the aeration pipe 4, avoiding localized strong oxygenation effects and localized weak oxygenation effects of the filter media within the tank. When air at a certain pressure is introduced into the aeration pipes 4, the second airflow aerates from bottom to top in the support layer through the single-pore membrane air diffusers, oxidizing and degrading the wastewater in the filter media layer 5.

[0074] Preferably, the top of the aeration ring 7 is 500-1500 mm higher than the top of the support layer 8. The airflow at the opening at the top of the aeration ring interacts with the external airflow, constantly changing direction, and aerates the filter media above.

[0075] Preferably, the aeration ring 7 is strip-shaped, and its axis is perpendicular to the length direction of the tank; or, the aeration ring 7 is a spherical cap. The aeration ring 7 can have various shapes. In this preferred embodiment, the aeration ring 7 is strip-shaped with a symmetrical arc-shaped cross-section. Both the top and bottom ends of the aeration ring 7 have openings. The bottom surface of the aeration ring 7 has a bottom cavity located on both sides of the bottom opening. As another shape, the aeration ring 7 is a spherical cap, i.e., the upper part above the plane is cut off from the upper part of the sphere with a plane, and the lower part below the plane is cut off from the lower part of the sphere with another plane. The bottom surface of the spherical cap has an annular bottom cavity that communicates with the wall cavity of the spherical cap. Figure 6 As shown, the spherical aeration rings 7 are arranged in rows and staggered in 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. In this way, the first airflow injected from the outer aeration holes 74 of different aeration rings collides and mixes with each other in multiple directions, ensuring that different surfaces of the filter media are in full contact with oxygen, thus improving the utilization rate of the filter media.

[0076] Preferably, the bottom cavity 71 is an annular cavity. The annular shape of the bottom cavity 71 ensures that the airflow from the intake pipe 3 into the bottom cavity 71 flows evenly into the wall cavity 72, preventing localized strong and weak airflow after entering the wall cavity 72. When air at a certain pressure is introduced into the intake pipe 3, the air enters the bottom cavity 71 and then enters the wall cavity 72.

[0077] Preferably, the top opening area of ​​the aeration ring 7 is larger than the bottom opening area. This allows the aeration ring 7 to provide inward aeration, balancing the aeration volume per unit area and slightly exceeding the aeration intensity at the bottom.

[0078] Preferably, the axis of the inner aeration hole 74 intersects the axis of the aeration ring 7; the axis of the outer aeration hole 73 intersects the axis of the aeration ring. When air at a certain pressure, i.e., the first airflow, is introduced into the air inlet pipe 3, the first airflow enters the wall cavity and is sprayed through the inner aeration hole 74 onto the filter media layer in the inner cavity of the aeration ring 7. This aeration volume is the inner aeration volume Q2. Along the inner wall of the aeration ring 7, from bottom to top, the aeration direction gradually changes from upward to downward, oxidizing and degrading the wastewater. Simultaneously, the first airflow is sprayed through the outer aeration hole 73 onto the filter media layer outside the aeration ring 7. This aeration volume is Q3. Along the outer wall of the aeration ring 7, from bottom to top, the aeration direction gradually changes from downward to upward, oxidizing and degrading the wastewater. Thus, the angle of the first airflow ejected from different inner aeration holes 74 is different. The angle of the first airflow ejected from different outer aeration holes 73 is also different. The first airflow at different angles acts on filter media placed at different angles to enhance the oxidative degradation effect on wastewater.

[0079] Preferably, the internal aeration holes 74 are evenly distributed on the inner wall of the aeration ring 7, and the external aeration holes 73 are evenly distributed on the outer wall of the aeration ring 7. The pore diameter of both the internal and external aeration holes 74 and 73 is 80-120 μm. The evenly distributed internal and external aeration holes 74 and 73 can make the filter media in the filter layer 5 more uniformly subjected to the oxygenation effect of the first airflow.

[0080] Preferably, the aeration rate of the opening at the top of the aeration ring 7 is equal to aQ1S. 上 / S 下 Where Q1 represents the aeration volume of the aeration pipe 4 within the aeration ring 7, and S 上 S represents the top opening area of ​​aeration ring 7. 下 This represents the bottom opening area of ​​aeration ring 7, and 'a' represents the adjustment coefficient, with a value ranging from 1.1 to 1.3. 上 Greater than S 下 This ensures that the aeration intensity at the top of the aeration ring 7 is greater than that at the bottom, thereby providing multi-directional oxygenation to the filter media inside the aeration ring and oxidizing and degrading the wastewater from multiple directions.

[0081] 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 pipe 4. This aeration volume serves as an auxiliary aeration volume for the aerated biological filter, enhancing aeration in multiple directions and the mutual cutting effect, improving oxygen transfer efficiency, and strengthening the oxidative degradation effect of the multi-directional filter media. In this preferred embodiment, aeration and oxygenation of the filter media by the aeration pipe 4 is the primary method, while aeration and oxygenation of the filter media by the aeration ring 7 is an auxiliary method. Air volume is rationally allocated because the depth of the filter media layer is greater than the height of the aeration ring, and the portion above the aeration ring needs continued aeration and oxygenation.

[0082] In the above embodiment, compressed air enters the aeration ring 7, and the air is sprayed in different directions from the inner aeration hole 74 and the outer aeration hole 73. Specifically, below the parting surface of the aeration ring 7, air is sprayed downwards and outwards through the outer aeration holes 73 on both sides of the aeration ring at different heights, radii, and tilt angles. From bottom to top, the angle between the spray direction and the horizontal plane gradually decreases. This downward spraying at different tilt angles aerates and oxygenates different surfaces of the filter media, increasing the contact probability with the filter media surfaces at different tilt states, enhancing the contact area between air and filter media, and improving the oxidative degradation capacity of wastewater. Meanwhile, a second airflow, sprayed upwards from different positions in the X direction (the length direction of the tank), aerates and oxygenates the filter media on the vertical surface of the filter media, oxidizing and degrading the wastewater. After the first and second airflows aerate and oxygenate the filter media in different directions of the filter media layer, due to the different directions of the two airflows, they violently cut each other when they meet, making the bubbles smaller and denser. At different heights, the spray radius varies, causing the airflow direction to constantly change after being cut off at different heights, resulting in more oxygen dissolving in the water. Simultaneously, by continuously changing direction and increasing the oxygen's movement path, multi-directional aeration and oxygenation occur within the filter media layer, further enhancing the contact area with the filter media and improving the oxidative degradation efficiency of wastewater.

[0083] Air from different directions below the parting surface of the left aeration ring 7 mixes and cuts, then changes direction to aerate and oxygenate different surfaces of the filter media 5 along different paths and directions. Similarly, air from different directions below the parting surface of the right aeration ring 7 also mixes and cuts, changing direction to aerate and oxygenate different surfaces of the filter media 5 along different paths and directions (opposite to the left). Because the air jets from the external aeration holes 73 on the left and right sides are directed in opposite directions, the two mixed air streams aerate and oxygenate the filter media within the filter media layer, and upon meeting, they cut each other again, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. Simultaneously, the continuous change in direction and increased oxygen movement path within the filter media layer further enhances the contact area and path with the filter media, further strengthening the oxidative degradation effect on wastewater.

[0084] The air-water mixture formed between each pair of aeration rings continues upwards, with the distance between them constantly changing from the lowest to the highest point. Below the parting surface, the cross-sectional area between the aeration rings gradually decreases from bottom to top, resulting in less space for airflow and a gradual increase in air velocity. This continuously changes the direction of airflow, enhancing the airflow effect and thus increasing the probability of contact with different surfaces of the polyhedral filter media. This effectively improves aeration and oxygenation, enhancing the oxidative degradation of wastewater. When the air reaches the parting surface AA, the cross-sectional area between the two aeration rings is at its minimum, the airflow velocity reaches its maximum, and the airflow direction changes further, further increasing the probability of contact with different surfaces of the polyhedral filter media.

[0085] Above the parting surface of the aeration rings, from bottom to top, the cross-sectional area between the two aeration rings gradually increases, resulting in a larger airflow space. Specifically, the mainstream airflow direction in the middle section is upward, while the mainstream airflow direction in the side section is diffused. This gradual lateral diffusion of air enhances the airflow effect and continuously changes the airflow direction, thus increasing the contact probability with different surfaces of the polyhedral filter media, effectively improving aeration and oxygenation, and enhancing the oxidative degradation efficiency of wastewater. This gradual lateral diffusion of air occurs in two ways: when the aeration ring is strip-shaped, the air gradually diffuses to both sides of the aeration ring; when the aeration ring is spherical, the air gradually diffuses to all sides of the aeration ring. Below the parting surface of the aeration rings, from bottom to top, the cross-sectional area between the two aeration rings gradually decreases, and the airflow space becomes smaller and smaller. Specifically, the mainstream airflow direction in the middle section is upward, while the mainstream airflow direction in the side section converges towards the middle. The air gradually converges towards the middle, thereby enhancing the airflow effect and continuously changing the airflow 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 oxidation and degradation efficiency of wastewater.

[0086] Simultaneously, the external aeration holes 73 above the wall cavity parting surface spray air upwards and outwards at different heights, radii, and tilt angles. The angle between the upward spray direction and the horizontal plane gradually increases, aerating and oxygenating different surfaces of the filter media at different tilt angles within the filter media layer. Below the wall cavity parting surface, the external aeration holes 73 spray air downwards and outwards at different heights, radii, and tilt angles. The angle between the upward spray direction and the horizontal plane gradually decreases, aerating and oxygenating different surfaces of the filter media at different tilt angles within the filter media layer. This increases the contact probability with the filter media surfaces at different tilt positions, aerating and oxygenating the filter media surfaces at different tilt angles at different heights within the filter media layer, thus oxidizing and degrading the wastewater. The second airflow diffusing laterally between every two aeration rings and the first airflow sprayed upwards from the external aeration holes 73, due to their different flow directions, undergo intense mutual cutting when they meet, making the bubbles smaller and denser, allowing more oxygen to dissolve in the water. At different heights, due to the arc shape of the wall cavity, the radius range of the first airflow jet is different. Therefore, the flow direction of the mixed airflow after being cut by each other at different heights is constantly changing, which increases the contact probability with the filter media surface at different inclinations, transfers more oxygen into the water, and effectively improves the oxygen transfer efficiency.

[0087] Because the filter media is polyhedral, the mixed airflow, after multiple mixing and cutting processes, continuously changes its flow direction, thus increasing the contact area and path between the wastewater and the filter media. This continuously balances the contact effect, further enhancing the chances of pollutants in the wastewater being trapped by the filter media layer, and increasing the probability of biodegradation and transformation of the wastewater by the biodegradation attached to the filter media, as well as the removal of dissolved organic matter. The constantly changing direction of the mixed airflow causes more filter media to change their position and angle, thereby increasing the contact area between the wastewater and the filter media, increasing the utilization rate of the filter media, enhancing the chances of pollutants in the wastewater being trapped by the filter media layer, and increasing the probability of biodegradation and transformation by the biodegradation attached to the filter media, as well as the removal of dissolved organic matter.

[0088] like Figure 2 and Figure 4 As shown, inside the aeration ring 7, the second airflow Q1 is injected upward through the aeration pipe 4, while the first airflow Q2 is injected inward at an angle from the inner aeration hole 74. Since the two airflows have different directions, they collide and cut each other violently when they meet.

[0089] Below the parting surface of the aeration ring, on the one hand, the angle between the first airflow, which is injected obliquely inward from bottom to top, and the horizontal plane gradually decreases. When it reaches the parting surface, the velocity direction is horizontal. The velocity direction of the airflow mixed with the vertically upward-moving second airflow continuously changes, with the angle between the velocity direction and the horizontal plane gradually decreasing upwards. This increases the probability of contact with the filter media surfaces at different inclines, transferring more oxygen into the water and effectively improving oxygen transfer efficiency. On the other hand, from bottom to top, the cross-sectional area of ​​the aeration ring gradually increases, and the airflow space becomes larger. Specifically, the mainstream airflow direction in the middle section is upward, while the mainstream airflow direction in the sides is diffused. The air gradually diffuses to the sides, thereby enhancing the airflow effect and continuously changing the airflow direction. This increases the probability of contact with different surfaces of the multifaceted filter media, effectively improving the aeration and oxygenation effect and enhancing the oxidation and degradation efficiency of wastewater.

[0090] Above the parting surface of 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. The velocity direction after mixing with the second airflow, which is moving vertically upward, continuously changes, with the velocity direction increasing further upward. This increases the contact probability with the filter media surfaces at different inclines, transferring more oxygen into the water and effectively improving oxygen transfer efficiency. On the other hand, the cross-sectional area of ​​aeration ring 7 gradually decreases from bottom to top, resulting in less space for airflow. Specifically, the mainstream airflow direction in the middle section is upward, while the mainstream airflow direction in the sides converges inward, gradually converging towards the center. This strengthens the airflow effect and continuously changes the airflow direction. Therefore, it increases the contact probability with different surfaces of the polyhedral filter media, effectively improving aeration and oxygenation, and enhancing the oxidative degradation efficiency of wastewater.

[0091] Within the inner cavity of the aeration ring 7, the aeration volume of the second airflow flowing vertically upward is Q1, and the aeration volume of the first airflow injected obliquely inward through the inner aeration hole 74 is Q2. Within different radii above and below the parting surface, the first and second airflows, injected in different directions, undergo thorough mixing and cutting, 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, balancing the aeration and oxygenation effects and biodegradation efficiency in each direction, effectively improving the retention of suspended solids and the biodegradation effect.

[0092] Below and above the parting line, on one hand, the angle between the first airflow, which is injected obliquely upwards and inwards, and the horizontal plane gradually decreases. When it reaches the parting line, the velocity direction is horizontal, and then the angle gradually increases upwards. The velocity direction of the second airflow, which is moving vertically upwards, also changes continuously. The angle between the velocity direction and the horizontal plane gradually decreases, reaching its minimum at the parting line, and then gradually increases, increasing the contact probability with the filter media surfaces at different inclinations, transferring more oxygen into the water, and effectively improving oxygen transfer efficiency. On the other hand, from bottom to top, the cross-sectional area of ​​the aeration ring gradually increases, the airflow space becomes larger, and the mainstream direction of the airflow on the sides is diffused, with the air gradually diffusing to the sides. When it reaches the parting line, the cross-sectional area of ​​the aeration ring is at its maximum. Further upwards, the cross-sectional area of ​​the aeration ring gradually decreases, the airflow space becomes smaller, and the airflow velocity gradually increases, continuously changing the airflow direction. Specifically, this manifests as follows: the mainstream airflow direction in the middle section is upward, while the mainstream airflow direction in the side section converges inward. The air gradually converges towards the center, thereby enhancing the airflow effect. This increases the probability of contact with different surfaces of the polyhedral filter media, effectively improving the oxygenation efficiency. Consequently, it increases the chances of pollutants in wastewater being trapped by the filter media layer, and increases the biodegradation and transformation of substances attached to the filter media. At the same time, it increases the probability of removing dissolved organic matter.

[0093] Air inside the aeration ring escapes at high speed from the top. When the second airflow, diffusing laterally above the parting surface between adjacent aeration rings, meets the first airflow, which is injected obliquely upwards from the external aeration holes 73, they violently cut each other, making the bubbles smaller and denser, thus dissolving more oxygen in the water. The second airflow, gradually diffusing laterally, moves outwards and upwards along an arc. Because the cross-sectional area at the bottom between the two aeration rings is larger than that at the top, and considering the first airflow injected between them from the external aeration holes, the aeration rate per unit area at the top is much greater than that at the bottom. Therefore, the air velocity diffusing outwards from between the two aeration rings is greater than the air velocity at the bottom. The high-speed collision of the second airflow between the aeration rings with the first airflow escaping from inside the aeration rings causes the two airflows to violently cut and mix again, further making the bubbles smaller and denser, thereby improving oxygen transfer efficiency. Meanwhile, the mixed airflow constantly changes direction, thereby enhancing the airflow effect and increasing the probability of contact with different surfaces of the polyhedral filter media. This effectively improves the aeration and oxygenation efficiency, thereby increasing the chances of pollutants in the wastewater being trapped by the filter media layer and increasing the biodegradation and transformation of the biomaterials attached to the filter media. It also increases the probability of removing dissolved organic matter.

[0094] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the claimed invention.

Claims

1. An aeration method for a wastewater treatment biological aerated filter, characterized by, The method includes: Step 1: Open the valve of the sewage inlet pipe (1), close the valve of the backwash inlet pipe (2), open the outlet, and the sewage enters the tank through the sewage inlet pipe (1). The sewage moves from bottom to top in the tank and passes through the filter plate (9), the support layer (8), and the filter media 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 provides auxiliary aeration and oxygenation to the filter media in the filter media layer (5). Open the valve of the aeration pipe (4), and the second airflow provides main aeration and oxygenation to the filter media in the filter media layer (5). Step 2: After the preset working time, close the sewage inlet pipe (1) and the outlet, and backwash the aerated biological filter. Step 3, return to step 1 until aeration stops; The aerated biological filter includes a tank body and filter plates (9), a support layer (8), and a filter media layer (5) arranged sequentially from bottom to top within the tank body. An aeration ring (7) is located in the filter media layer (5). The top and bottom of the aeration ring (7) are provided with openings. The aeration ring (7) is strip-shaped, and the end face cross-section of the aeration ring (7) is symmetrically arc-shaped. Below the parting surface of the aeration ring (7), the width of the end face of the aeration ring (7) gradually increases from bottom to top. Above 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. 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 interconnected, 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 external aeration hole (73), and the inner wall is provided with an internal aeration hole (74). When the valve of the air inlet pipe (3) is opened, the first airflow enters the aeration ring (7), and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer (5); when the valve of the aeration pipe (4) is opened, the second airflow provides primary aeration and oxygenation to the filter media in the filter media layer (5), including: In the inner cavity of the aeration ring (7), from bottom to top, the angle between the first airflow injected into the inner aeration hole (74) and the horizontal plane gradually decreases. When it reaches the parting surface, the velocity 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. In the inner cavity of the aeration ring (7), the first airflow injected inward by the inner aeration hole (74) mixes with the second airflow injected vertically upward by the aeration pipe (4). The velocity direction of the mixed airflow changes continuously. The angle between the velocity direction and the horizontal plane gradually decreases first. When it reaches the parting surface, the angle is the smallest. Then it gradually increases, so that the mixed airflow aerates and oxygenates the filter media with different tilt angles.

2. The aeration method according to claim 1, characterized by, When the valve of the air inlet pipe (3) is opened, the first airflow enters the aeration ring (7) and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer (5); Open the valve of the aeration pipe (4), and the second airflow will perform main aeration and oxygenation on the filter media in the filter media layer (5), including: Below the parting surface on the outer side 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 media layer (5), and then continues to run upward to the outer wall of the aeration ring (7), changes direction and reflects 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 continuously increases, and the reflected fluid gradually changes from tilted downward to tilted upward, aerating and oxygenating the filter media at different tilt angles.

3. The aeration method according to claim 1, characterized by, When the valve of the air inlet pipe (3) is opened, the first airflow enters the aeration ring (7) and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer (5); Open the valve of the aeration pipe (4), and the second airflow will perform main aeration and oxygenation on the filter media in the filter media layer (5), including: Below the outer parting surface of the aeration ring (7), the first airflow is sprayed downward and outward through the external aeration holes (73) at different heights and different tilt angles. From bottom to top, the angle between the direction of the first airflow spray and the horizontal plane gradually decreases, and different surfaces of the filter material are aerated and oxygenated at different tilt angles downward. Above the outer parting surface of the aeration ring (7), the first airflow is sprayed upward and outward through the external aeration holes (73) at different heights and different tilt angles. From bottom to top, the angle between the direction of the first airflow spray and the horizontal plane gradually increases, and different surfaces of the filter material are aerated and oxygenated at different tilt angles. Outside the aeration ring (7), the second airflow sprayed upward by the aeration pipe (4) aerates and oxygenates the filter media in the filter media layer (5) and oxidizes and degrades the wastewater. When the second airflow and the first airflow sprayed by the external aeration hole (73) mix, they cut each other, making the bubbles smaller and denser. At different heights, the flow direction of the mixed airflow after mutual cutting changes, allowing more oxygen to dissolve in the water and aerating and oxygenating in the filter media layer (5) in multiple directions.

4. The aeration method according to claim 1, characterized in that, When the valve of the air inlet pipe (3) is opened, the first airflow enters the aeration ring (7) and the first airflow provides auxiliary aeration and oxygenation to the filter media in the filter media layer (5); Open the valve of the aeration pipe (4), and the second airflow will perform main aeration and oxygenation on the filter media in the filter media layer (5), including: The first airflows ejected from the external aeration holes (73) on the opposite wall surfaces between two adjacent aeration rings (7) meet and cut each other after aerating and oxygenating the filter media, forming a mixed airflow that aerates and oxygenates the filter media in the filter media layer (5). The first airflow ejected from the outer aeration holes (73) on the opposite wall surface 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, forming a mixed airflow, which aerates and oxygenates the filter material in the filter layer (5).

5. The aeration method according to claim 1, characterized by, Step 2 involves backwashing the aerated biological filter, including: Air is introduced into the air inlet pipe (3) and the aeration pipe (4); Between the aeration rings (7), the second airflow injected vertically upward from the aeration pipe (4) and the first airflow injected from the outer aeration hole (73) of the aeration ring perform a combined backwashing of air, washing the filter material located outside the aeration ring (7), loosening the filter material layer, and removing suspended matter from the surface of the filter material. In the inner cavity of the aeration ring (7), the second airflow injected vertically upward from the aeration pipe (4) and the first airflow injected from the inner aeration hole (74) of the aeration ring perform a combined backwashing of the air, which washes the filter material located in the inner cavity of the aeration ring (7), loosens the filter material layer (5), and removes suspended matter from the surface of the filter material.

6. The aeration method according to claim 5, characterized by, Step 2, which involves backwashing the aerated biological filter, also includes performing a combined air-water backwash.

7. The aeration method according to claim 6, characterized by, The combined steam and water backwashing includes: Open the backwash inlet pipe (2) and introduce clean water into the backwash inlet pipe (2). After entering the tank, the clean water moves from bottom to top and washes the surface of the filter media. The suspended matter that has been separated from the surface of the filter media after being washed by air moves upward and leaves the filter media layer (5) and flows out from the outlet. During this process, air is continuously introduced into the air inlet pipe (3) and the aeration pipe (4).

8. The aeration method according to claim 7, characterized by, The combined steam and water backwashing also includes: Stop introducing air into the air inlet pipe (3) and aeration pipe (4), and continue to introduce clean water into the backwash water inlet pipe (2) to flush the suspended solids out of the pool.

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