A non-powered domestic sewage purification device based on composite filter media

Abstract

This utility model relates to the technical field of domestic sewage treatment equipment, and discloses a non-powered domestic sewage purification device based on composite filter media. It includes a screen well with a liftable interceptor cylinder inside, which can pre-intercept and easily clean large particles of debris in the influent; a pretreatment sedimentation chamber to achieve solid-liquid separation of sludge and sediment; and sewage entering the composite filter media purification chamber through an overflow channel. The purification chamber contains layered composite filter media bags, composed of modified ceramsite, zeolite particles, and biochar, which, combined with a ventilation component, provide natural convection oxygen supply, achieving deep purification through sewage adsorption and biodegradation. The tank adopts a split-sealed structure with annular reinforcing ribs and a permeable material-blocking structure, ensuring overall structural stability and preventing clogging and leakage. This utility model requires no power equipment, has low energy consumption, is easy to operate and maintain, and exhibits strong purification stability. It is suitable for decentralized on-site domestic sewage treatment scenarios such as rural households and small residential areas, and has high application and promotion value.

Description

Technical Field

[0001] This utility model relates to the technical field of domestic sewage treatment equipment, and in particular to a non-powered domestic sewage purification device based on composite filter media. Background Technology

[0002] In the field of decentralized domestic sewage treatment, for rural households, small villages, homestays and remote residential areas without centralized pipe network coverage, on-site purification equipment is usually used to complete the treatment of domestic sewage to meet standards. Gravity-free gravity-flow sewage purification devices have become the mainstream equipment for decentralized domestic sewage treatment due to their advantages of not requiring power-consuming equipment, low operating costs and suitability for buried installation. Existing similar non-powered sewage purification devices mostly adopt a simple bar interception combined with a single filter media filling structure, relying on gravity flow to achieve preliminary filtration and sedimentation treatment of sewage. The structure is simple and easy to install, and can meet the basic sewage purification operations with low concentration and low treatment requirements. It is widely used in small-scale decentralized sewage treatment scenarios.

[0003] However, existing non-powered domestic sewage purification devices still have many substantial technical defects in long-term actual operation, making it difficult to meet the current treatment requirements of stable discharge compliance, low maintenance, and high sealing performance. First, the inlet interception structure of traditional equipment is simple, relying solely on fixed filter screens to intercept debris. The filter screens are prone to clogging, and cleaning debris and disassembling and reassembling the filter screens after clogging are extremely cumbersome, resulting in a large workload for manual maintenance. Long-term use can easily lead to poor water intake and a decrease in overall treatment efficiency. Second, traditional equipment mostly uses a single filter media purification method, which has limited sewage adsorption and degradation capacity, a single purification level, and poor removal effect on pollutants such as organic matter, nitrogen, and phosphorus in the water body, resulting in insufficient stability of effluent water quality. At the same time, the natural oxygen supply structure design of traditional equipment is unreasonable, resulting in insufficient oxygen supply inside the cavity, low activity of biological flora on the filter media surface, and poor biodegradation effect. Therefore, a non-powered domestic sewage purification device based on composite filter media is proposed to solve the above problems. Utility Model Content

[0004] To overcome the above shortcomings, this utility model provides a non-powered domestic sewage purification device based on composite filter media, which aims to improve the problems of easy clogging and inconvenient cleaning of the inlet interception structure of the non-powered domestic sewage purification device based on composite filter media in the prior art, insufficient purification capacity of single filter media and poor natural oxygen supply effect, resulting in poor effluent water quality stability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a non-powered domestic sewage purification device based on composite filter media, comprising an integrated PE tank, wherein a bar screen well is provided at the inlet end of the integrated PE tank, and a ventilation component is vertically mounted on the top of the integrated PE tank; a partition is fixedly installed inside the integrated PE tank, the partition dividing the interior of the tank into a pretreatment sedimentation chamber and a composite filter media purification chamber, an overflow channel is provided on the top of the partition, the bar screen well is connected to the pretreatment sedimentation chamber through a connecting pipe, the pretreatment sedimentation chamber is connected to the composite filter media purification chamber through the overflow channel, a plurality of composite filter media bags are placed inside the composite filter media purification chamber, and an outlet channel is provided on the lower side wall of the composite filter media purification chamber.

[0006] As a further description of the above technical solution: the bar screen well adopts a prefabricated plastic cylindrical structure, the inner side wall of the bar screen well is fixedly provided with a limit block, the side wall of the bar screen well is equipped with a water inlet pipe, the elevation of the water inlet pipe is higher than the elevation of the connecting pipe, the bar screen well is detachably equipped with an intercepting mesh cylinder, the intercepting mesh cylinder is supported on the limit block and spans across the water inlet flow path, and the top of the bar screen well is threaded with an openable and sealable maintenance cover.

[0007] As a further description of the above technical solution:

[0008] The inspection manhole cover is movably fitted with a rotatable disc at its axial center position. A vertically arranged adjusting rod is fixedly connected to the bottom of the rotating disc. A pressure plate is threaded onto the outside of the adjusting rod. A connecting rod is fixedly connected between the pressure plate and the inspection manhole cover to achieve circumferential limiting and fixing. The bottom end of the adjusting rod is connected to the intercepting net cylinder. A damping spring is provided between the rotating disc and the pressure plate, sleeved on the outside of the adjusting rod.

[0009] As a further description of the above technical solution:

[0010] The integrated PE tank has annular reinforcing ribs arranged on the outer wall to enhance structural strength. At least two sets of maintenance manholes are provided on the top of the integrated PE tank. The two sets of maintenance manholes are respectively arranged above the pretreatment sedimentation chamber and the composite filter material purification chamber, and each maintenance manhole is equipped with a sealing cover structure.

[0011] As a further description of the above technical solution:

[0012] The composite filter media package is encapsulated and formed using a water-permeable non-woven fabric material. The interior of the composite filter media package is filled with a multi-layered composite filter media, which includes at least modified ceramsite, zeolite particles, and biochar. Multiple sets of the composite filter media packages are evenly arranged inside the composite filter media purification chamber in a layered stacking manner.

[0013] As a further description of the above technical solution:

[0014] The ventilation assembly includes a vertical ventilation pipe and a rainproof ventilation cap mounted on the top of the vertical ventilation pipe. The lower end of the vertical ventilation pipe extends into the upper cavity of the composite filter material purification chamber, and natural air convection is used to achieve unpowered autonomous oxygen supply and ventilation within the cavity.

[0015] As a further description of the above technical solution:

[0016] The bottom of the pretreatment sedimentation chamber is formed with a sedimentation zone for accumulating and settling impurities and sludge. A permeable baffle is horizontally fixed inside the composite filter media purification chamber. The permeable baffle is horizontally arranged between the bottom of the composite filter media bag and the top of the water outlet channel to support the filter media bag, prevent the filter media from sinking, and avoid clogging of the water outlet channel.

[0017] As a further description of the above technical solution:

[0018] The integrated PE tank adopts a left-right split assembly structure. Locking flanges are fixedly installed at the joint positions of the tank. Sealing strips are sandwiched between the two sets of locking flanges and locked and fixed by fastening bolts to achieve overall sealed assembly of the tank.

[0019] This utility model has the following beneficial effects:

[0020] 1. This utility model adopts a gravity-fed, self-flowing, and naturally ventilated oxygen supply system, eliminating the traditional operation mode of domestic sewage treatment equipment that relies on power equipment such as water pumps and fans. The entire process does not require electricity to drive water transport and oxygen supply to the chamber, significantly reducing equipment operating energy consumption and subsequent maintenance costs. It is suitable for rural remote areas without power supply, small-scale individual households, and outdoor scattered sewage treatment scenarios. Through a multi-stage purification system of pre-screening, gravity sedimentation pretreatment, and multi-layer composite filter material biological adsorption degradation, it removes impurities, silt, organic matter, and nitrogen and phosphorus pollutants from sewage step by step. The purification stages are complete and the treatment effect is stable, effectively solving the problems of low treatment accuracy and substandard effluent quality of traditional simple purification equipment. It can reliably meet the environmental discharge standards for on-site harmless treatment of small-scale domestic sewage.

[0021] 2. In this utility model, the integrated PE tank combined with annular reinforcing ribs and a split flange sealing structure effectively improves the equipment's resistance to pressure deformation and overall sealing performance after underground installation, preventing sewage leakage, odor leakage, and groundwater backflow. The equipment has a long service life and strong environmental adaptability. The front-mounted bar screen well is equipped with a liftable extrusion-type intercepting net cylinder, which can quickly clean and intercept debris, preventing filter screen blockage from affecting water flow efficiency. At the same time, the dual-chamber independent maintenance manhole design facilitates regular sludge removal, filter media replacement, and equipment maintenance. Combined with a permeable material blocking and anti-clogging structure and a layered filter media arrangement, it effectively prevents filter media drift, sinking, and outlet blockage, ensuring long-term continuous and stable operation of the equipment and making it suitable for widespread application. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a non-powered domestic sewage purification device based on composite filter media proposed in this utility model.

[0023] Figure 2 This is a cross-sectional view of an integrated PE tank structure for a non-powered domestic sewage purification device based on composite filter media proposed in this utility model.

[0024] Figure 3 This is a cross-sectional view of the bar screen structure of a non-powered domestic sewage purification device based on composite filter media proposed in this utility model.

[0025] Legend:

[0026] 1. Integrated PE tank; 2. Grille well; 3. Ventilation assembly; 4. Composite filter media bag; 11. Pretreatment sedimentation chamber; 111. Sludge settling zone; 12. Composite filter media purification chamber; 13. Water outlet channel; 14. Annular reinforcing rib; 15. Inspection manhole; 16. Permeable baffle plate; 17. Locking flange; 18. Partition plate; 19. Overflow channel; 21. Limiting block; 22. Inlet pipe; 23. Connecting pipe; 24. Interception net cylinder; 25. Inspection manhole cover; 26. Connecting rod; 27. Pressure plate; 28. Rotating disc; 29. ​​Adjusting rod; 210. Damping spring; 31. Vertical ventilation pipe; 32. Rainproof vent cap; 41. Modified ceramsite; 42. Zeolite granules; 43. Biochar. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] Reference Figure 1 , Figure 2 , Figure 3 This utility model provides an embodiment of a non-powered domestic sewage purification device based on composite filter media, comprising an integrated PE tank 1. The integrated PE tank 1 is made of corrosion-resistant, anti-aging, and lightweight PE material, with strong overall structural stability, capable of long-term adaptation to outdoor and underground buried installation environments, resistant to acid and alkali corrosion, and not easily damaged or deformed. A bar screen 2 is installed at the inlet end of the integrated PE tank 1 for pre-interception treatment of large particles of debris at the sewage inlet. A ventilation assembly 3 is vertically mounted on the top of the integrated PE tank 1 to provide natural ventilation and oxygen supply to the internal purification chamber. Vertically arranged partitions 18 are fixedly installed inside the integrated PE tank 1. The partitions 18 are integrated sealed plate structures, dividing the interior of the integrated PE tank 1 into independent pretreatment sedimentation chambers 11 and composite filter chambers 12. The composite filter media purification chamber 12 has two functional chambers. The upper surface of the partition 18 is provided with a through overflow channel 19 to connect the water flow between the two chambers. The side wall of the bar screen 2 is connected and fixed with a connecting pipe 23. The bar screen 2 is connected to the interior of the pretreatment sedimentation chamber 11 through the connecting pipe 23. The pretreatment sedimentation chamber 11 is connected to the composite filter media purification chamber 12 through the overflow channel 19 at the top, forming a step-by-step gravity-flow water flow path. Several sets of composite filter media packs 4 are placed inside the composite filter media purification chamber 12 as the core treatment medium for deep purification of sewage. The lower side wall of the composite filter media purification chamber 12 is provided with a through outlet channel 13 for the stable discharge of purified water. The entire device relies on the gravity of the sewage to achieve full gravity-flow purification, without the need for external water pumps, blowers or other power transmission equipment, truly realizing fully automatic sewage treatment operation without power.

[0029] Reference Figure 2 , Figure 3 The bar screen 2 adopts an integral prefabricated plastic cylinder structure. This prefabricated, one-piece structure boasts high strength, good sealing, and convenient installation, enabling it to independently complete the pretreatment of incoming water debris interception. Limiting blocks 21 are fixedly installed on the inner wall of the bar screen 2. These blocks are evenly distributed in a ring or multi-point pattern, providing stable support points for the internal interception structure. The side wall of the bar screen 2 is equipped with horizontally arranged inlet pipes 22. The elevation of the inlet pipes 22 is higher than that of the connecting pipes 23, utilizing the height difference to create a natural hydraulic drop, ensuring that sewage can stably flow into the tank. Simultaneously, it can effectively... To prevent sewage backflow, the inside of the bar screen well 2 is detachably equipped with an intercepting mesh cylinder 24. The bottom end of the intercepting mesh cylinder 24 is supported on the limiting block 21 and is installed across the water flow path between the inlet pipe 22 and the connecting pipe 23. All incoming sewage must pass through the intercepting mesh cylinder 24, which can effectively intercept solid debris such as hair, plastic bags, suspended solids, and large particles, preventing debris from entering the tank and causing pipe blockage and filter media contamination. The top of the bar screen well 2 is threaded with an inspection cover 25. The threaded connection structure is easy to install and remove, and can achieve sealing and quick opening for inspection of the top of the bar screen well 2.

[0030] Reference Figure 2 , Figure 3 A rotating disk 28 is movably mounted at the axial position of the manhole cover 25. The rotating disk 28 can rotate coaxially with the manhole cover 25. A vertically arranged adjusting rod 29 is vertically fixed to the bottom of the rotating disk 28. The adjusting rod 29 extends into the intercepting net cylinder 24. A pressure plate 27 is threaded onto the outer side of the adjusting rod 29. The pressure plate 27 and the adjusting rod 29 form a screw thread transmission structure. A vertically arranged connecting rod 26 is fixedly connected between the pressure plate 27 and the manhole cover 25. The connecting rod 26 realizes the circumferential limitation and vertical fixation of the pressure plate 27, so that the pressure plate 27 cannot rotate. The vertical movement retains only the threaded lifting and lowering freedom of the adjusting rod 29. The bottom end of the adjusting rod 29 is fixedly connected to the top of the intercepting net cylinder 24, which can synchronously drive the intercepting net cylinder 24 to rise and fall vertically. A damping spring 210 is provided between the rotating disk 28 and the pressure plate 27. The damping spring 210 is sleeved on the outside of the adjusting rod 29. Under normal conditions, it can play the role of elastic buffering and anti-loosening limit. By rotating the rotating disk 28, the adjusting rod 29 can be driven to rise and fall vertically relative to the fixed pressure plate 27, thereby driving the intercepting net cylinder 24 to rise and fall, realizing the convenient operation and maintenance functions of squeezing out debris, lifting and removing, and quick cleaning.

[0031] Reference Figure 1 , Figure 2 The outer wall of the integrated PE tank 1 is uniformly provided with multiple annular reinforcing ribs 14. The annular reinforcing ribs 14 are integrally formed with the tank body, which can significantly improve the overall structural strength and compressive strength of the tank body, effectively resist the soil pressure and water pressure after buried installation, prevent the tank body from deforming and cracking, and improve the overall service life of the equipment. The top of the integrated PE tank 1 is provided with at least two sets of independent maintenance manholes 15. The two sets of maintenance manholes 15 are respectively arranged above the pretreatment sedimentation chamber 11 and the composite filter media purification chamber 12, so as to realize independent maintenance of each chamber. Each set of maintenance manholes 15 is equipped with a sealing cover plate, which can seal the manhole position to prevent rainwater and debris from falling into the tank body, while avoiding the overflow of sewage odor. It is also easy to open, which is convenient for staff to regularly clean, inspect, and replace the filter media.

[0032] Reference Figure 1 , Figure 2The composite filter media pack 4 is made of highly permeable and corrosion-resistant permeable non-woven fabric. The non-woven fabric has uniform pores and excellent water permeability, which can prevent the leakage of filter media particles while ensuring rapid penetration and flow of sewage. The composite filter media pack 4 is filled with a uniformly proportioned composite filter media system. The composite filter media is mainly composed of modified ceramic particles 41, zeolite particles 42 and biochar 43. The multiple filter media work together to have multiple functions such as adsorbing heavy metals, intercepting suspended solids, adsorbing organic pollutants, attaching biofilm, degrading organic matter in sewage, and adjusting the pH of water. Multiple sets of composite filter media packs 4 are evenly arranged in the composite filter media purification chamber 12 in a layered stacking manner to form a multi-layer gradient purification filter layer, extend the sewage filtration path, and significantly improve the sewage purification accuracy and treatment effect.

[0033] Reference Figure 1 , Figure 2 The ventilation component 3, as the core structure of the device's non-powered oxygen supply, includes a vertical ventilation pipe 31 and a rainproof ventilation cap 32. The vertical ventilation pipe 31 is vertically fixed on the top of the integrated PE tank 1, with its top end extending outside the tank and fitted with a rainproof ventilation cap 32. This effectively prevents rainwater, fallen leaves, and debris from entering the cavity. The lower end of the vertical ventilation pipe 31 extends into the upper cavity area of ​​the composite filter material purification chamber 12, keeping the inside of the purification chamber connected to the outside atmosphere. Utilizing the temperature difference between indoors and outdoors and the principle of natural air convection, the cavity can achieve continuous non-powered ventilation and oxygen supply, providing sufficient oxygen for the aerobic microorganisms attached to the filter material surface, ensuring the continuous and stable progress of the biodegradation reaction, eliminating the need for manual oxygen supply equipment, and further reducing equipment energy consumption and operation and maintenance costs.

[0034] Reference Figure 1 , Figure 2 The bottom of the pretreatment sedimentation chamber 11 is formed with a recessed sludge settling area 111. The sludge settling area 111 is the lowest point of the chamber. After the sewage enters the pretreatment sedimentation chamber 11, the flow rate slows down. The silt, suspended particles and sedimenting impurities in the water can naturally settle and collect in the sludge settling area 111, realizing solid-liquid separation, effectively reducing the purification load of the subsequent filter media and reducing the probability of filter media blockage. The composite filter media purification chamber 12 is horizontally fixed with a permeable baffle plate 16. The permeable baffle plate 16 covers the entire cross-section of the chamber, with uniform water permeability and strong support. The permeable baffle plate 16 is horizontally arranged below the composite filter media bag 4 and above the water outlet channel 13. It can stably support all the layered and stacked composite filter media bags 4, effectively preventing the filter media bags from sinking or drifting due to long-term immersion in water. At the same time, it can intercept the falling fine filter media particles, completely avoiding fine particles from entering the water outlet channel 13 and causing pipeline blockage, ensuring smooth and stable water output.

[0035] Reference Figure 1 , Figure 2The integrated PE tank 1 adopts a left-right split assembly structure, which facilitates mass production, transportation, hoisting and on-site installation of the equipment. The joint position of the tank is fixed with symmetrically arranged locking flanges 17. A high-elasticity sealing strip is sandwiched between the two sets of opposing locking flanges 17. The two sets of fastening bolts are evenly locked and fixed, so that the two sets of tanks fit tightly together. The joint surface has extremely strong sealing performance, which can effectively prevent sewage leakage, odor leakage and groundwater backflow, and ensure the stability and sealing of the equipment during long-term buried operation.

[0036] Working principle:

[0037] Step 1: Inlet Bar Screening and Gravity Sedimentation Pretreatment. Domestic sewage flows into the bar screen well 2 through the inlet pipe 22. The water first passes through the interception net cylinder 24 spanning the water flow path. The mesh structure of the interception net cylinder 24 intercepts pollutants such as hair, suspended solids, and large particles in the sewage, achieving primary pretreatment of sewage. This effectively prevents impurities from entering the tank and causing blockage of subsequent pipes and filter media. After filtration, the sewage flows into the pretreatment sedimentation chamber 11 inside the integrated PE tank 1 by gravity through the connecting pipe 23. Due to the increased cross-sectional area of ​​the chamber and the slowed water flow, heavy pollutants such as silt and fine suspended particles in the sewage naturally settle under the action of gravity and finally accumulate in the sedimentation zone 111, completing solid-liquid separation pretreatment. This significantly reduces the treatment load of the subsequent deep purification unit and provides stable inlet conditions for subsequent filter media purification operations.

[0038] Step 2: After the pretreatment sedimentation of the supernatant, the wastewater smoothly overflows into the composite filter purification chamber 12 through the overflow channel 19 at the top of the partition 18. The wastewater passes through the multi-component layered composite filter bag 4 from top to bottom. The modified ceramic particles 41, zeolite particles 42 and biochar 43 inside the composite filter bag 4 work together to purify the wastewater. They can efficiently adsorb organic matter, nitrogen and phosphorus pollutants, heavy metal ions and residual suspended solids in the wastewater. At the same time, a large number of aerobic microbial communities can be attached to the surface of the filter media. With the natural air convection formed by the vertical ventilation pipe 31 and the rainproof ventilation cap 32 of the top ventilation component 3, oxygen is continuously supplied to the inside of the chamber to ensure the normal metabolism and reproduction of microorganisms. Through biodegradation, organic pollutants in the wastewater are decomposed to achieve deep purification of water quality and significantly improve the wastewater purification compliance rate.

[0039] Step 3: Flow Stabilization Filtration and Drainage, and Convenient Operation and Maintenance. After deep purification by multiple layers of filter media, the water falls to the bottom area of ​​the composite filter media purification chamber 12. It undergoes a final flow stabilization filtration through the permeable baffle plate 16. The permeable baffle plate 16 can effectively intercept the falling fine filter media debris, preventing filter media from drifting and clogging the outlet channel 13, ensuring a uniform and stable water flow. Finally, the qualified clean water is smoothly discharged through the outlet channel 13, completing the entire non-powered sewage purification process. After long-term operation, the rotating disc 28 on the top of the maintenance manhole cover 25 can be rotated to drive the intercepting net cylinder 24 to rise and fall using screw drive, squeezing and draining the intercepted debris, and lifting and cleaning it. At the same time, the sludge in the sedimentation area 111 can be cleaned and the composite filter media bag 4 can be replaced through the top maintenance manhole 15, realizing convenient operation and maintenance of the equipment.

[0040] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A non-powered domestic sewage purification device based on composite filter media, comprising an integrated PE tank (1), characterized in that: The integrated PE tank (1) is equipped with a grid well (2) at the water inlet end, and the integrated PE tank (1) is vertically equipped with a ventilation component (3) at the top. The integrated PE tank (1) is fixedly provided with a partition (18) inside, which divides the tank into a pretreatment sedimentation chamber (11) and a composite filter media purification chamber (12). An overflow channel (19) is opened at the top of the partition (18). The grid well (2) is connected to the pretreatment sedimentation chamber (11) through a connecting pipe (23). The pretreatment sedimentation chamber (11) is connected to the composite filter media purification chamber (12) through the overflow channel (19). Several composite filter media bags (4) are placed inside the composite filter media purification chamber (12). A water outlet channel (13) is provided on the lower side wall of the composite filter media purification chamber (12).

2. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The grid well (2) adopts a prefabricated plastic cylindrical structure. A limiting block (21) is fixedly installed on the inner side wall of the grid well (2). A water inlet pipe (22) is installed on the side wall of the grid well (2). The elevation of the water inlet pipe (22) is higher than that of the connecting pipe (23). An intercepting net cylinder (24) is detachably installed inside the grid well (2). The intercepting net cylinder (24) is supported and placed on the limiting block (21) and spans across the water inlet flow path. An openable and sealed maintenance well cover (25) is threaded on the top of the grid well (2).

3. The non-powered domestic sewage purification device based on composite filter media according to claim 2, characterized in that: The inspection manhole cover (25) is movably fitted with a rotatable disc (28) at its axial position. The bottom of the disc (28) is fixedly connected to a vertically arranged adjusting rod (29). A pressure plate (27) is threaded onto the outside of the adjusting rod (29). A connecting rod (26) is fixedly connected between the pressure plate (27) and the inspection manhole cover (25) to achieve circumferential limiting and fixing. The bottom end of the adjusting rod (29) is connected to the intercepting net cylinder (24). A damping spring (210) is provided between the disc (28) and the pressure plate (27) and sleeved on the outside of the adjusting rod (29).

4. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The outer wall of the integrated PE tank (1) is provided with annular reinforcing ribs (14) to enhance the structural strength. At least two sets of maintenance manholes (15) are provided on the top of the integrated PE tank (1). The two sets of maintenance manholes (15) are respectively arranged above the pretreatment sedimentation chamber (11) and the composite filter material purification chamber (12), and the maintenance manholes (15) are all equipped with sealing cover structures.

5. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The composite filter media package (4) is encapsulated and formed using a water-permeable non-woven fabric material. The composite filter media package (4) is filled with a multi-layer composite filter media in proportion. The composite filter media includes at least modified ceramsite (41), zeolite particles (42), and biochar (43). Multiple sets of the composite filter media packages (4) are evenly arranged inside the composite filter media purification chamber (12) in a layered stacking manner.

6. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The ventilation assembly (3) includes a vertical ventilation pipe (31) and a rainproof ventilation cap (32) mounted on the top of the vertical ventilation pipe (31). The lower end of the vertical ventilation pipe (31) extends into the upper cavity of the composite filter material purification chamber (12) and uses natural air convection to achieve unpowered autonomous oxygen supply and ventilation in the cavity.

7. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The bottom of the pretreatment sedimentation chamber (11) is formed with a sedimentation zone (111) for accumulating and settling impurities and sludge. The interior of the composite filter media purification chamber (12) is horizontally fixed with a permeable baffle plate (16). The permeable baffle plate (16) is horizontally arranged between the bottom of the composite filter media bag (4) and the top of the water outlet channel (13) to support the filter media bag, prevent the filter media from sinking and avoid blockage of the water outlet channel.

8. The non-powered domestic sewage purification device based on composite filter media according to claim 1, characterized in that: The integrated PE tank (1) adopts a left and right split assembly structure. Locking flanges (17) are fixedly installed at the joint position of the tank. Sealing strips are sandwiched between the two sets of locking flanges (17) and locked and fixed by fastening bolts to achieve overall sealing assembly of the tank.

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