Sponge iron reinforced AO cooperative treatment method and device for distributed rural domestic sewage

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a sponge iron reinforced AO cooperative treatment method and device for decentralized rural domestic sewage, the device comprises a treatment box, the treatment box is composed of a left box body and a right box body which are communicated with each other; a sewage treatment tank is arranged at the bottom of an inner cavity of the left box body, an anaerobic treatment section is arranged above the sewage treatment tank, a biological filler layer for filtering and removing suspended particulate matters in water is arranged in the anaerobic treatment section, and a multi-layer structure of the biological filler layer is sequentially filled with functional fillers made of different materials from top to bottom; the modular serial arrangement of an anaerobic treatment section, an aerobic treatment section and sludge precipitation is combined with a graded reflux system, so that suspended particulate matter filtration, organic matter hydrolytic acidification, anaerobic denitrification / phosphorus release and aerobic nitrification / phosphorus uptake are realized in sequence. The function division is clear, the flow level is clear, and the nitrogen and phosphorus removal efficiency can be improved.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically a method and device for the sponge iron-enhanced AO synergistic treatment of decentralized rural domestic wastewater. Background Technology

[0002] Rural domestic sewage constitutes a significant source of water pollution in my country, and its discharge generally lacks effective treatment, causing continuous damage, especially to water bodies in ecologically sensitive areas. Due to factors such as the wide geographical distribution of rural areas, the dispersed population, the high cost of pipeline construction, and the complex terrain, the applicability of traditional centralized sewage treatment models is limited in rural areas, and there is an urgent need to develop low-investment, high-efficiency treatment facilities adapted to decentralized rural domestic sewage.

[0003] Current mainstream decentralized rural domestic wastewater treatment technologies mainly include ecological technologies such as constructed wetlands, soil infiltration, stabilization ponds, and ecological filter beds. These technologies generally have advantages such as flexibility, adaptability, low cost, sustainability, and simple operation, making them suitable for decentralized, small-scale domestic wastewater treatment. However, these technologies face significant technical bottlenecks. Their treatment efficiency is generally constrained by factors such as weather and geography, and they suffer from insufficient stability in operation and maintenance management over the long term. In addition, rural domestic wastewater often suffers from insufficient carbon sources. Wastewater with a low C / N ratio often performs poorly with the above treatment technologies without an external carbon source, making it difficult to meet strict wastewater discharge standards.

[0004] As an integrated biological and ecological treatment technology, AO technology has a stronger resistance to hydraulic and pollution loads compared to traditional ecological treatment technologies. It is suitable for treating rural domestic sewage with high concentrations of organic pollutants and can effectively reduce the content of pollutants such as COD and SS. However, this technology faces the dual constraints of operating costs and treatment efficiency. Without the addition of an additional carbon source, it is also difficult to achieve the required nitrogen and phosphorus removal efficiency for sewage with a low carbon-to-nitrogen ratio.

[0005] Existing research indicates that the addition of iron-based fillers, represented by zero-valent iron (ZCE), can effectively improve the simultaneous nitrogen and phosphorus removal efficiency of the AO process for rural domestic sewage. Iron-based fillers can enhance biological treatment efficiency through electrochemical action, iron reduction, coagulation and sedimentation enrichment, and synergistic effects with iron-containing microorganisms. Among these, sponge iron, with its larger specific surface area and higher surface energy, is particularly effective in overcoming the bottleneck of low carbon-to-nitrogen ratio treatment. In AO process systems, sponge iron can serve as a biofilm carrier, introducing inorganic electron donors to compensate for the low microbial activity and poor nitrogen and phosphorus removal efficiency of traditional AO processes under low carbon-to-nitrogen ratio conditions. However, in actual decentralized rural sewage treatment scenarios, this technology has not yet formed a mature engineering application model.

[0006] Currently, decentralized treatment facilities generally suffer from inherent drawbacks such as high complexity in long-term operation and maintenance. While modular integrated systems can effectively integrate technological advantages and simplify management processes, the combination of integrated AO systems and sponge iron reinforcement processes still lacks practical verification, resulting in the failure to fully unleash the technological potential in the field of rural sewage treatment.

[0007] Therefore, the present invention provides a method and apparatus for the sponge-iron-enhanced AO co-treatment of decentralized rural domestic sewage. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0009] The technical solution adopted by the present invention to solve its technical problem is: the decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device of the present invention includes a treatment box, which is composed of a left box and a right box that are interconnected; The bottom of the inner cavity of the left box is equipped with a sewage treatment tank, and an anaerobic treatment section is provided above the sewage treatment tank. The anaerobic treatment section is equipped with a biological packing layer for filtering and removing suspended particulate matter in the water. The multi-layer structure of the biological packing layer is filled with functional packing materials of different materials from top to bottom. The right chamber is divided into an aerobic treatment section and a sedimentation chamber by a vertically arranged partition. The aerobic treatment section is equipped with an aeration device. The left box body has an inlet pipe installed on its side wall at a position corresponding to the sewage treatment tank, for introducing sewage into the sewage treatment tank.

[0010] Preferably, the biological packing layer is configured from top to bottom as an activated carbon packing layer, a zeolite packing layer, and a gravel packing layer.

[0011] Preferably, the front end of the aerobic treatment section is connected to the anaerobic treatment section via a connecting channel, and polyurethane ball-wrapped sponge iron particles are placed at the bottom of the aerobic treatment section as a biofilm carrier.

[0012] Preferably, the anaerobic treatment section and the sedimentation chamber are respectively provided with sludge return pipes and nitrification liquid return pipes on both sides.

[0013] Preferably, the sedimentation chamber is equipped with an inclined plate to facilitate sludge settling, and an outlet pipe is provided on the top side.

[0014] Preferably, in the anaerobic treatment section, multiple support frames are fixed at intervals in the vertical direction, and each of the biological packing layers is slidably disposed in the placement cavity between two adjacent support frames. The side wall of the left box is provided with an opening at a position corresponding to the placement cavity, and a closed door is hinged to the outer wall of the opening.

[0015] Preferably, the biological filler layer includes a placement frame, which is vertically divided into multiple movable chambers by a support frame II. A loading unit is slidably inserted into each movable chamber. The loading unit includes a rectangular frame, with a filter screen fixed on the upper and lower sides of the rectangular frame, and a handle fixed on the side wall of the rectangular frame. The side of the placement frame facing the closed door is open.

[0016] Preferably, the lower support frame and the adjacent placement frame are provided with a movable cavity. The top of the movable cavity is open and the opening is located at the top of the adjacent placement frame. A buffer rod is slidably arranged inside the movable cavity. A connecting block is fixed to the bottom of the buffer rod, and a spring is provided at the bottom of the connecting block.

[0017] Preferably, the top of the aerobic treatment section is provided with air holes.

[0018] A method for decentralized rural domestic sewage treatment using a sponge-iron-enhanced AO co-treatment device includes the following steps: S1. Start the pump to introduce decentralized rural domestic sewage into the sewage treatment tank through the inlet pipe for preliminary sedimentation to remove some suspended particulate matter; S2. The settled wastewater flows upwards through a three-stage biological packing layer: the gravel packing layer physically intercepts suspended particles and distributes water evenly; the zeolite packing layer enhances ammonia nitrogen removal through ion exchange and supports biofilm growth; the activated carbon packing layer adsorbs organic pollutants and serves as a microbial carrier; after completing filtration, hydrolysis acidification, and denitrification / phosphorus release, it enters the aerobic treatment section. S3: Polyurethane-coated sponge iron particles are added to the bottom of the aerobic treatment section to promote autotrophic denitrification and chemical phosphorus removal through micro-electrolysis; DO is maintained at 2-4 mg / L through intermittent bottom aeration to complete the nitrification / phosphorus uptake process. S4. Wastewater enters the sedimentation chamber with inclined plates, and sludge settles rapidly to the bottom of the tank through the inclined plates; S5. The settled sludge and nitrified liquor are returned to the anaerobic treatment section through the sludge return pipe and nitrification liquor return pipe to adjust the hydraulic retention time and enhance pollutant removal; S6. After treatment, the water is discharged from the outlet pipe at the top of the sedimentation chamber, completing the treatment process.

[0019] The beneficial effects of this invention are as follows: Wastewater flows into the wastewater treatment tank through the inlet pipe for initial sedimentation. It then flows vertically through a gravel packing layer, a zeolite packing layer, and an activated carbon packing layer for suspended particulate matter removal and anaerobic hydrolysis acidification. Afterward, it flows into the aerobic treatment section where aeration combined with the enhanced electrochemical and microbial synergistic effect of sponge iron packing achieves simultaneous nitrogen and phosphorus removal. Finally, it flows into the sedimentation tank, where sludge and suspended particulate matter settle, and the treated effluent is discharged through the effluent pipe. This technology employs a modular series arrangement of anaerobic treatment section → aerobic treatment section → sludge sedimentation, combined with a staged reflux system, to sequentially achieve: suspended particulate matter filtration, organic matter hydrolysis acidification, anaerobic denitrification / phosphorus release, and aerobic nitrification / phosphorus uptake. Its functional zoning and clear process hierarchy enhance nitrogen and phosphorus removal efficiency. Attached Figure Description

[0020] The invention will now be further described with reference to the accompanying drawings.

[0021] Figure 1 This is a perspective view of the present invention; Figure 2 This is another schematic diagram of the present invention; Figure 3 This is a cross-sectional view of the present invention; Figure 4 This is a top view of the internal structure of the processing box in this invention; Figure 5 yes Figure 3 Enlarged view of point A in the middle; Figure 6 This is a partial structural schematic diagram of the present invention; Figure 7 This is a schematic diagram of the structure of the placement frame and the loading unit in this invention; Figure 8 This is a flowchart of the method of the present invention.

[0022] In the diagram: 1. Treatment tank; 2. Sludge return pipe; 3. Inlet pipe; 4. Sealed door; 5. Aeration device; 6. Air vent; 7. Outlet pipe; 8. Wastewater treatment tank; 9. Aerobic treatment section; 10. Sedimentation chamber; 11. Anaerobic treatment section; 12. Biological packing layer; 13. Connecting trough; 14. Baffle; 15. Nitrified liquid return pipe; 16. Support frame one; 17. Placement chamber; 18. Handle; 19. Placement frame; 20. Support frame two; 21. Rectangular frame; 22. Filter screen; 23. Movable chamber; 24. Buffer rod; 25. Connecting block; 26. Spring. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] Example 1: As Figures 1 to 7As shown in the embodiment of the present invention, the decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device includes a treatment tank 1, which is composed of a left tank and a right tank that are interconnected. The bottom of the inner cavity of the left box is provided with a sewage treatment tank 8, and an anaerobic treatment section 11 is provided above the sewage treatment tank 8. The anaerobic treatment section 11 is provided with a biological packing layer 12 for filtering and removing suspended particulate matter in the water. The multi-layer structure of the biological packing layer 12 is filled with functional packing materials of different materials from top to bottom. The right chamber is divided into an aerobic treatment section 9 and a sedimentation chamber 10 by a vertically arranged partition 14. The aerobic treatment section 9 is equipped with an aeration device 5. The left box body has an inlet pipe 3 installed on its side wall at a position corresponding to the sewage treatment tank 8, which is used to introduce sewage into the sewage treatment tank 8.

[0025] Preferably, the biological packing layer 12 is configured from top to bottom as an activated carbon packing layer, a zeolite packing layer, and a gravel packing layer.

[0026] Preferably, the front end of the aerobic treatment section 9 is connected to the anaerobic treatment section 11 through the connecting groove 13, and the bottom of the aerobic treatment section 9 is filled with sponge iron particles wrapped with polyurethane balls as a biofilm carrier.

[0027] Preferably, the anaerobic treatment section 11 and the sedimentation chamber 10 are respectively provided with sludge return pipe 2 and nitrification liquid return pipe 15 on both sides.

[0028] Preferably, the sedimentation chamber 10 is equipped with an inclined plate to facilitate sludge settling, and a water outlet pipe 7 is provided on the top side.

[0029] During operation, the pump is turned on, and decentralized rural domestic sewage enters the sewage treatment tank 8 through the inlet pipe 3, where preliminary sedimentation occurs, removing some suspended particulate matter. The settled sewage flows upwards, passing sequentially through the three-stage biological packing layer 12 within the anaerobic treatment section 11. First is the gravel packing layer (using particles with a diameter of 3-6 mm), which retains suspended particulate matter through physical interception and also provides uniform water distribution. Next is the zeolite packing layer (using particles with a diameter of 2-4 mm), which utilizes the ion exchange characteristics of zeolite and its highly selective adsorption of ammonium ions to enhance ammonia nitrogen removal, while also serving as a good porous carrier to support biofilm growth. Finally, there is the activated carbon packing layer (using particles with a diameter of 1-2 mm), which reduces the organic pollution load (such as ammonia nitrogen and total nitrogen) in the sewage through adsorption and also acts as a microbial carrier. After treatment by these three biological packing layers 12, the sewage completes processes such as filtration, hydrolysis acidification, and denitrification / phosphorus release, and then enters the aerobic treatment section 9 through the connecting tank 13. At the bottom of the aerobic treatment section 9, sponge iron particles (2-5mm in diameter) wrapped in polyurethane balls are added. Their micro-electrolysis promotes microbial autotrophic denitrification and chemical precipitation for phosphorus removal. Aeration pipes extending from the side at the bottom provide precise oxygen supply through intermittent aeration, maintaining DO at 2-4 mg / L to complete the nitrification / phosphorus uptake process. Afterward, the wastewater enters the sedimentation chamber 10 with inclined plates, where sludge rapidly settles to the bottom. The settled sludge and nitrified liquid are returned to the anaerobic treatment section 11 via the sludge return pipe 2 and the nitrification liquid return pipe 15, adjusting the hydraulic retention time to enhance pollutant removal (the return process uses existing, publicly available, and mature technology; the relevant equipment can be commercially available products, and their specific structure and working principle are not detailed here). Finally, the treated water is discharged from the effluent pipe 7 at the top of the sedimentation chamber 10, completing the entire wastewater treatment process.

[0030] Preferably, in the anaerobic treatment section 11, multiple support frames 16 are fixed at intervals in the vertical direction, and each of the biological packing layers 12 is slidably disposed in the placement cavity 17 between two adjacent support frames 16. The side wall of the left box is provided with an opening at a position corresponding to the placement cavity 17, and a closed door 4 is hinged to the outer wall of the opening.

[0031] During operation, when maintenance or replacement of the biological packing layer 12 is required, first lower the water level inside the left chamber to below the biological packing layer 12. Then, open the closed door 4 hinged to the outer wall of the opening. Since the biological packing layer 12 is slidably positioned in the placement cavity 17 between two adjacent support frames 16, it can be easily pulled out of the placement cavity 17. After maintenance or replacement, the biological packing layer 12 is reinserted into the placement cavity 17, and the closed door 4 is closed to restore normal operation of the device. This makes the maintenance and replacement of the biological packing layer 12 more convenient, reduces downtime, and improves treatment efficiency.

[0032] In addition, a sealing structure is provided between the closed door 4 and the outer wall of the tank. For example, a rubber sealing strip is installed on the contact surface between the closed door 4 and the outer wall of the tank, and a groove is designed on the edge of the closed door 4 to cooperate with the protrusion of the tank. This double sealing design effectively prevents sewage leakage. When the closed door 4 is closed, the rubber sealing strip is compressed and deformed, filling the tiny gap between the door and the tank, while the cooperation between the groove and the protrusion plays a role in positioning and assisting the sealing, further enhancing the sealing effect. This sealing structure is not only simple and reliable, but also low in cost, and can meet the needs of long-term stable operation of rural sewage treatment devices.

[0033] Preferably, the biological filler layer 12 includes a placement frame 19, in which multiple filling units are stacked and slidably inserted, and a support frame 20 is sandwiched between two adjacent filling units. Each filling unit includes a rectangular frame 21, with a filter screen 22 fixed on the upper and lower sides of the rectangular frame 21, and a handle 18 fixed on the side wall of the rectangular frame 21. The side of the placement frame 19 facing the closed door 4 is open.

[0034] During operation, as wastewater flows from bottom to top through the biological packing layer 12 during wastewater treatment, the packing material at the bottom has more contact with the wastewater and is subject to relatively greater contamination and wear, while the packing material at the top is relatively cleaner. When the packing material needs to be replaced or maintained, the operator can pull out the bottom loading unit from the movable chamber using the handle 18. The upper loading unit can then fall down to fill the empty space. At this point, only the removed loading unit needs to be cleaned or replaced with a new one, and then it can be reinserted into the empty space at the top. This design makes packing material replacement more targeted, eliminating the need to replace the entire biological packing layer 12, significantly reducing maintenance costs. Furthermore, the filter screens 22 fixed on the upper and lower sides of the rectangular frame 21 of the loading unit ensure smooth wastewater passage while effectively trapping the packing material and preventing its loss. Meanwhile, a support frame 20 is sandwiched between two adjacent feeding units. The support frame 20 separates the adjacent feeding units, reducing the friction between the filter screens 22 during the pulling and pulling of the feeding units, thus preventing damage to the filter screens 22 and improving the service life of the device.

[0035] The lower support frame 16 and the adjacent placement frame 19 are provided with movable cavities 23. The top of the movable cavity 23 is open and the opening is located on the top of the adjacent placement frame 19. A buffer rod 24 is slidably arranged inside the movable cavity 23. Each of the four corners of each support frame 16 is provided with a buffer rod 24. A connecting block 25 is fixed to the bottom of the buffer rod 24, and a spring 26 is provided at the bottom of the connecting block 25.

[0036] During operation, under the squeezing action of the bottom loading unit, the buffer rod 24 is retracted into the movable cavity 23, at which point the spring 26 is compressed. When cleaning or replacing a new loading unit is required, the bottom loading unit must be pulled out first. During the pulling process, the inner buffer rod 24 is released first, extending upwards under the elastic force of the spring 26 and rising to its highest point. As the rectangular frame 21 completely passes through the outer buffer rod 24, the rectangular frame 21 will still support the bottom of the second loading unit for a certain distance, allowing the outer buffer rod 24 to rise upwards. After the bottom loading unit is completely pulled out, the second loading unit will fall completely on top of the buffer rod 24. At this time, the buffer rod 24 provides a certain buffering and support effect under the action of the spring 26, allowing the second loading unit to descend slowly, preventing it from falling directly and colliding with the lower support frame 16, which could cause damage.

[0037] Example 2: Figure 1 and Figure 2 As shown in the comparative embodiment one, another embodiment of the present invention is as follows: the top of the aerobic treatment section 9 is provided with air holes 6. During operation, the air holes 6 play an important role in balancing the air pressure. When the aeration device 5 is working, the air pressure inside the aerobic treatment section 9 will gradually increase. The presence of the air holes 6 allows the air pressure inside the aerobic treatment section 9 to be maintained within a relatively stable range, which not only ensures the normal operation of the aeration device 5, but also avoids the adverse effects caused by excessively high air pressure.

[0038] like Figure 8 As shown, a method for the decentralized treatment of rural domestic sewage using a sponge-iron-enhanced AO co-treatment device includes the following steps: S1. Start the pump and introduce decentralized rural domestic sewage into the sewage treatment tank 8 through the inlet pipe 3 for preliminary sedimentation to remove some suspended particulate matter; S2. After sedimentation, the wastewater flows upward through a three-stage biological packing layer 12: the gravel packing layer physically intercepts suspended particles and distributes water evenly; the zeolite packing layer enhances ammonia nitrogen removal through ion exchange and supports biofilm growth; the activated carbon packing layer adsorbs organic pollutant load and serves as a microbial carrier; after completing filtration, hydrolysis acidification, and denitrification / phosphorus release, it enters the aerobic treatment section 9. In section S3, polyurethane-coated sponge iron particles are added to the bottom of the aerobic treatment section 9. Micro-electrolysis is used to promote autotrophic denitrification and chemical phosphorus removal. Intermittent bottom aeration is used to maintain DO at 2-4 mg / L to complete the nitrification / phosphorus uptake process. S4. Wastewater enters the sedimentation chamber 10 with inclined plates, and sludge rapidly settles to the bottom of the tank via the inclined plates; S5. The settled sludge and nitrified liquor are returned to the anaerobic treatment section 11 through the sludge return pipe 2 and the nitrification liquor return pipe 15 to adjust the hydraulic retention time and enhance pollutant removal. S6. After treatment, the water is discharged from the outlet pipe 7 at the top of the sedimentation chamber 10, completing the treatment process.

[0039] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0041] 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 above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A decentralized sponge-iron-enhanced AO co-treatment device for rural domestic sewage, characterized in that... The system includes a processing box (1), which is composed of a left box and a right box that are interconnected. The bottom of the inner cavity of the left box is provided with a sewage treatment tank (8), and an anaerobic treatment section (11) is provided above the sewage treatment tank (8). The anaerobic treatment section (11) is provided with a biological packing layer (12) for filtering and removing suspended particulate matter in the water. The multi-layer structure of the biological packing layer (12) is filled with functional packing materials of different materials from top to bottom. The right chamber is divided into an aerobic treatment section (9) and a sedimentation chamber (10) by a vertically arranged partition (14). The aerobic treatment section (9) is equipped with an aeration device (5). The left box body has an inlet pipe (3) at a position corresponding to the sewage treatment tank (8) for introducing sewage into the sewage treatment tank (8).

2. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... The biological packing layer (12) is arranged from top to bottom as an activated carbon packing layer, a zeolite packing layer and a gravel packing layer.

3. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... The front end of the aerobic treatment section (9) is connected to the anaerobic treatment section (11) through a connecting channel (13), and the bottom of the aerobic treatment section (9) is filled with sponge iron particles wrapped with polyurethane balls as a biofilm carrier.

4. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... The anaerobic treatment section (11) and the sedimentation chamber (10) are respectively equipped with sludge return pipe (2) and nitrification liquid return pipe (15) on both sides.

5. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... The sedimentation chamber (10) is equipped with an inclined plate to facilitate sludge settling, and an outlet pipe (7) is provided on the top side.

6. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... In the anaerobic treatment section (11), multiple support frames (16) are fixed at intervals in the vertical direction. Each biological packing layer (12) is slidably disposed in the placement cavity (17) between two adjacent support frames (16). The side wall of the left box is provided with an opening at a position corresponding to the placement cavity (17). The outer wall of the opening is hinged with a closed door (4).

7. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 6, characterized in that... The biological filler layer (12) includes a placement frame (19), in which multiple loading units are stacked and slidably inserted, and a support frame (20) is sandwiched between two adjacent loading units. The loading unit includes a rectangular frame (21), and a filter screen (22) is fixed on the upper and lower sides of the rectangular frame (21). A handle (18) is fixed on the side wall of the rectangular frame (21). The side of the placement frame (19) facing the closed door (4) is open.

8. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 7, characterized in that... The support frame (16) located below and the adjacent placement frame (19) are provided with a movable cavity (23). The top of the movable cavity (23) is open and the opening is located on the top of the adjacent placement frame (19). A buffer rod (24) is slidably arranged inside the movable cavity (23). A connecting block (25) is fixed at the bottom of the buffer rod (24). A spring (26) is provided at the bottom of the connecting block (25).

9. The decentralized rural domestic sewage sponge iron-enhanced AO co-treatment device according to claim 1, characterized in that... The top of the aerobic treatment section (9) is provided with air holes (6).

10. A method for decentralized rural domestic sewage treatment using sponge-iron-enhanced AO co-treatment, wherein the method employs any one of the decentralized rural domestic sewage treatment devices according to claims 1-9, characterized in that... Includes the following steps: S1. Start the pump body and introduce decentralized rural domestic sewage into the sewage treatment tank (8) through the inlet pipe (3) for preliminary sedimentation to remove some suspended particulate matter; S2. After sedimentation, the wastewater flows upward through a three-stage biological packing layer (12): the gravel packing layer physically intercepts suspended particles and distributes water evenly; the zeolite packing layer enhances ammonia nitrogen removal through ion exchange and supports biofilm growth; the activated carbon packing layer adsorbs organic pollutant load and serves as a microbial carrier; after completing filtration, hydrolysis acidification, denitrification / phosphorus release, it enters the aerobic treatment section (9). S3, Aerobic treatment section (9): Polyurethane-coated sponge iron particles are added to the bottom to promote autotrophic denitrification and chemical phosphorus removal through micro-electrolysis; DO is maintained at 2-4 mg / L through intermittent bottom aeration to complete the nitrification / phosphorus uptake process; S4. Wastewater enters the sedimentation chamber (10) with inclined plates, and sludge settles rapidly to the bottom of the tank through the inclined plates; S5. The settled sludge and nitrified liquid are returned to the anaerobic treatment section (11) through the sludge return pipe (2) and the nitrification liquid return pipe (15) to adjust the hydraulic retention time and enhance pollutant removal. S6. After treatment, the water is discharged from the outlet pipe (7) at the top of the sedimentation chamber (10), completing the treatment process.

Images