A decentralized treatment system for rural domestic sewage and a method of using the same

Abstract

The present application relates to a kind of rural domestic sewage decentralized treatment system and its use method, and the treatment system includes water storage tank, filter tank group, and tank body, the filter tank group includes two filter tanks being arranged in parallel and being located on the both sides of the rotation center of lever structure, liquid inlet pipe being connected with filter tank and water storage tank, and liquid inlet valve on liquid inlet pipe, the filter tank is equipped with filter plate with several filter holes, the filter tank is also provided with suction port, the filter tank bottom end is connected with drain pipe with drain valve, the side of tank body is also provided with limiting structure limiting tank body movement.The present application is used in, water storage tank and filter tank group are set before tank body, large particles in sewage are filtered and removed, cleaning frequency is reduced, it is guaranteed to use water storage tank to concentrate water storage, then filter tank group is used to filter sewage in water storage tank in batches, it is guaranteed to the practicality of sewage treatment, two filter tanks are used to filter sewage alternately, so that the continuous filtration of sewage is realized.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more particularly to the field of rural wastewater technology, specifically to a decentralized rural domestic wastewater treatment system and its usage method. Background Technology

[0002] In rural areas, due to the dispersed residential patterns and relatively sparse population density, traditional centralized sewage treatment systems are difficult to adapt to due to high construction costs and difficulties in laying pipelines. Therefore, decentralized sewage treatment technology, with its flexibility and adaptability, has become an effective way to solve rural sewage problems. Decentralized sewage treatment equipment is widely used in rural areas, typically possessing high daily treatment capacity to meet the sewage treatment needs of villages of varying sizes. However, during long-term operation, the lack of regular maintenance and cleaning, coupled with the relative scarcity of electricity resources in rural areas, leads to huge energy consumption and less than ideal efficiency in sewage treatment. Electricity consumption is particularly significant in key treatment stages such as aeration; using grid-connected electricity for aeration would significantly increase operating costs. Furthermore, the various complex treatment components within the equipment make maintenance very difficult, especially with the packing material accumulating large amounts of dirt or aging biofilm after prolonged use. Without effective cleaning, equipment maintenance costs increase, ultimately leading to a deterioration in the quality of the treated sewage.

[0003] Chinese invention patent application CN202411331193.9 discloses a wind and solar integrated treatment device for decentralized domestic sewage to solve the above problems. However, due to the presence of many large and small particles in rural sewage, the sludge in the tank increases, making cleaning more difficult. Therefore, a filter structure for removing large and small particles needs to be installed in front of the tank. Chinese invention patent application CN202210313425.2 discloses a decentralized treatment system and a decentralized sewage pretreatment device for rural domestic sewage. However, this device relies on the gravity of the water in the storage tank as a trigger condition. Since the water inflow into the storage tank cannot be guaranteed, it is not suitable for actual sewage treatment. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a decentralized rural domestic sewage treatment system and its usage method. A water storage tank and a filter tank assembly are installed before the main tank to filter and remove large particles in the sewage, reducing the frequency of cleaning. At the same time, the water storage tank is used to centrally store water, and the filter tank assembly filters the sewage in the water storage tank in stages, ensuring the practicality of sewage treatment.

[0005] This invention is achieved through the following technical solution: a decentralized rural domestic sewage treatment system, comprising a water storage tank, a plurality of filter tank groups connected to the water storage tank, and a tank body connected to the filter tank groups. The tank body is provided with an anaerobic fermentation zone, an aerobic fermentation zone, a packing purification zone, and a water storage zone arranged sequentially. The filter tank group includes two filter tanks arranged in parallel and located on both sides of the rotation center of the lever structure, an inlet pipe connecting the filter tanks and the water storage tank, and an inlet valve located on the inlet pipe. The filter tank is provided with a filter plate with a plurality of filter holes, and a filter rod extending to the top of the filter tank is connected to the filter plate. The filter tank is also provided with a suction port, and a drain pipe with a drain valve is connected to the bottom of the filter tank. The side of the filter tank is also provided with a limiting structure to restrict the movement of the filter tank.

[0006] In use, this invention involves setting up a water storage tank and a filter tank assembly before the main tank to filter out large particles in the wastewater, reducing the frequency of cleaning. The water storage tank is used to centrally store water, and the filter tank assembly filters the wastewater in the storage tank in stages, ensuring practicality for wastewater treatment. Two filter tanks are used alternately to filter the wastewater, achieving continuous filtration. The arrangement of the two filter tanks and the lever structure allows the filter tanks to move vertically, causing a relative change in the height of the filter plate and the filter tank. This moves the particles to the upper part of the filter tank, where the wastewater enters another filter pipe. The particles are then sucked away through the suction port, filtering them out of the wastewater and preventing the wastewater from being sucked away by the suction port.

[0007] Preferably, the upper end of the filter rod is connected to a telescopic motor. This preferred embodiment uses a telescopic motor to drive the filter plate up and down, thereby adjusting the position of the wastewater rinsing the filter plate. This fully utilizes the filter plate while preventing sludge from settling on it, and also keeps the sludge in a suspended state to prevent sludge deposition.

[0008] Preferably, the lever structure includes a horizontal plate axially connected to the bracket, a support rod fixed to the bottom of the filter tank, and a middle rod with both ends respectively hinged to the horizontal plate and the support rod. A guide sleeve that slides along the height direction on the bracket is fixed to the support rod.

[0009] This preferred solution achieves vertical lifting and lowering of the support rod and filter tank along the height direction by setting an intermediate rod and a guide sleeve.

[0010] Preferably, the lower end of the horizontal plate is provided with an upwardly extending buffer spring corresponding to the filter tank. In use, when the filter tank overcomes the limiting structure, the filter tank on the other side will accelerate. The buffer spring prevents the filter tank from descending too quickly and causing a collision.

[0011] Preferably, the filter tank is also connected to a pull rope, which passes around a fixed pulley and through a fixed plate to a trigger rod. A drain switch electrically connected to the drain valve is provided between the trigger rod and the fixed plate. The fixed plate is also provided with an intermediate spring that connects the fixed plate and the trigger rod and drives the trigger rod away from the fixed plate. The moving front ends of the two trigger rods are respectively provided with a forward switch and a reverse switch that drive the stepper motor to rotate forward and reverse. The output end of the stepper motor is insulated and connected to a switch knife. The circuits of the two inlet valves are arranged in parallel and are both connected in series with the switch knife.

[0012] In this preferred embodiment, when the left filter tank reaches the drainage position, the pull rope moves the trigger rod backward to touch the drain switch, opening the corresponding left drain valve. Simultaneously, the right trigger rod touches the reverse switch, causing the stepper motor to rotate in the opposite direction by a certain angle. This connects the switch blade to the circuit containing the right inlet valve, opening the right inlet valve. At the same time, the switch blade disconnects the circuit containing the left inlet valve, closing the left inlet valve. Thus, the position of the filter tank controls the change of sewage flow direction, ensuring the flow of sewage between the two filter tanks.

[0013] Preferably, the limiting structure includes a limiting rod that slides on the limiting plate and extends into the filter tank. A baffle is fixed to the limiting rod, and a limiting spring is provided between the baffle and the limiting plate to push the limiting rod to move into the filter tank. The end face of the limiting rod is spherical, and the filter tank has a groove that is adapted to the spherical surface of the limiting rod and allows the limiting rod to be inserted. Grooves are provided on the two opposite outer surfaces of the filter tank, and the grooves are correspondingly arranged with the limiting rod.

[0014] This preferred solution uses a baffle and a limiting spring to push the limiting rod into the groove, thus restricting the movement of the filter tank to a certain extent. The spherical end face of the limiting rod provides guidance, facilitating its movement out of the groove. When the limiting rod is not in the groove, the spring pushes it against the side of the filter tank, providing some support. Once inserted into the groove, the support is increased, effectively limiting the movement. When the left filter tank is draining and the right filter tank is filling, the limiting rod restricts the left filter tank from moving upwards for a certain period. During this time, the trigger rod on the left side remains in contact with the left drain switch, keeping the drain valve open and increasing the draining time in the left filter tank.

[0015] Preferably, the suction port is connected to a suction pump, and a suction button switch electrically connected to the suction pump is located in one of the grooves.

[0016] This preferred solution uses a push-button switch to trigger the suction pump to draw material when the filter tank reaches the drainage position.

[0017] Preferably, a one-way valve is provided on the liquid inlet of the filter tank, and an air exchange valve is also provided on the top of the filter tank.

[0018] This preferred solution uses a one-way valve to prevent particles from entering the inlet pipe when the filter plates move upwards, and uses an air exchange valve to ensure air pressure balance inside the filter tank.

[0019] Preferably, a transfer tank is provided between the drain pipe and the tank body. The transfer tank is connected to the drain pipe, and a level gauge is provided inside the transfer tank. An air outlet is provided on the transfer tank.

[0020] When this preferred solution is used, since the first area inside the tank is an anaerobic fermentation zone, it avoids the continuous inflow of sewage into the anaerobic fermentation zone, which would affect the anaerobic environment.

[0021] A method for using a decentralized rural domestic sewage treatment system includes the following steps:

[0022] In rural areas, sewage first enters a storage tank. A filter screen is installed at the inlet of the storage tank to filter out larger particles. At this time, the sewage in the storage tank includes wastewater and sludge. Then, the sludge is distributed to several filter tank groups for filtering out small particles.

[0023] In a set of filter tanks, two filter tanks are arranged side by side. The inlet valve on the left is open, and the inlet valve on the right is closed. Wastewater enters the filter tank on the left through the inlet pipe. At the same time, the telescopic motor drives the filter plate to move up and down, thereby adjusting the position of the wastewater on the filter plate. This makes full use of the filter plate while preventing sludge from settling on it. It also keeps the sludge in a suspended state to prevent sludge from settling. As the filter plate moves up and down, the particulate matter remains on the filter plate, while the sludge and wastewater enter the lower end of the filter plate. As wastewater continues to enter, the left tank descends. After descending to a certain height, the horizontal plate presses on the buffer spring, which acts as a buffer. When the left filter tank descends to the drainage position, the limit rod of the limit device is inserted into the groove. At this time, the pull rope drives the trigger rod to move backward, triggering the drain switch. The drain valve opens, and the wastewater on the left enters the middle tank. At the same time, the limit rod triggers the suction pump, which runs for a certain period of time to suck away the particulate matter on the filter plate.

[0024] When the left filter tank reaches the drain position, the right filter tank reaches the liquid inlet position under the action of the horizontal plate. At this time, under the action of the middle spring, the trigger rod on the right side contacts the reverse switch and triggers it, causing the stepper motor to reverse. This disconnects the circuit between the switch knife and the left liquid inlet valve, and connects the circuit between the right liquid inlet valve and the left liquid inlet valve, thereby closing the left liquid inlet valve and opening the right liquid inlet valve, allowing sewage to flow into the right filter tank, thus achieving uninterrupted filtration of wastewater.

[0025] As wastewater flows out of the left filter tank, wastewater enters the right filter tank. As the weight of the right filter tank gradually increases, the force exerted by the horizontal plate on the left filter tank gradually increases. When this force overcomes the resistance of the limit rod on the filter tank, the left filter tank moves upward. At this point, the suction pump stops working. At this time, some residue will remain in the left filter tank. As wastewater continuously enters the right filter tank, the right filter tank descends while the left filter tank rises, thus repeating this process to filter the wastewater.

[0026] The filtered wastewater enters the transfer tank, then the main tank, where it passes through the anaerobic fermentation zone, aerobic fermentation zone, and packing purification zone before finally entering the storage area, thus achieving wastewater treatment.

[0027] The beneficial effects of this invention are as follows: A water storage tank and a filter tank assembly are installed before the main tank to filter and remove large particles from the wastewater, reducing the frequency of cleaning. Simultaneously, the water storage tank is used to centrally store water, and the filter tank assembly filters the wastewater in the storage tank in stages, ensuring the practicality of wastewater treatment. Furthermore, two filter tanks are used to alternately filter the wastewater, thus achieving continuous filtration. By setting up two filter tanks and a lever structure, the filter tanks can move along the height direction, causing a relative change in the height of the filter plate and the filter tank. This allows particles to be carried to the upper part of the filter tank, where the wastewater enters another filter pipe. The particles are then sucked away through the suction port, filtering them out of the wastewater and preventing the wastewater from being sucked away by the suction port. When the left filter tank reaches the drainage position, the pull rope moves the trigger rod backward to touch the drain switch, opening the corresponding left drain valve. At the same time, the right trigger rod touches the reverse switch, causing the stepper motor to rotate in the opposite direction by a certain angle. This connects the switch knife to the circuit where the right inlet valve is located, opening the right inlet valve. Simultaneously, the switch knife disconnects the circuit where the left inlet valve is located, closing the left inlet valve. Thus, the position of the filter tank controls the change of wastewater flow direction, ensuring the flow of wastewater between the two filter tanks. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention;

[0029] Figure 2 This is an enlarged schematic diagram of the filter tank assembly;

[0030] Figure 3 This is a schematic diagram of the trigger lever.

[0031] Figure 4 This is a circuit diagram of the switch knife.

[0032] Figure 5 This is a top view of the limiting device.

[0033] As shown in the figure:

[0034] 1. Filter tank assembly; 11. Filter tank; 12. Filter rod; 13. Groove; 14. Limiting structure; 15. Inlet pipe; 16. Inlet valve; 17. Suction port; 18. Filter plate.

[0035] 2. Tank body; 21. Anaerobic fermentation zone; 22. Aerobic fermentation zone; 23. Packing material purification zone; 24. Water storage zone.

[0036] 30. Horizontal plate; 31. Center of rotation of the horizontal plate; 32. Drain pipe; 33. Drain valve; 34. Buffer spring; 35. Intermediate rod; 36. Guide sleeve; 37. Support rod; 4. Transfer tank; 5. Switch knife; 51. Circuit with one drain valve; 52. Circuit with another drain valve.

[0037] 61. Pull rope; 62. Fixed pulley; 63. Fixed plate; 64. Intermediate spring; 65. Drain switch; 66. Trigger rod; 67. Forward rotation switch.

[0038] 70. Suction button; 71. Limit rod; 72. Baffle; 73. Limit spring; 74. Limit plate. Detailed Implementation

[0039] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0040] See attached document Figure 1-5 This invention discloses a decentralized rural domestic sewage treatment system, characterized in that it includes a water storage tank, a plurality of filter tanks 11 connected to the water storage tank, and a tank body 2 connected to the filter tanks 11. The tank body 2 is provided with an anaerobic fermentation zone 21, an aerobic fermentation zone 22, a packing purification zone 23, and a water storage zone 24 arranged sequentially. A filter screen is provided at the water inlet of the water storage tank, and a stirring rod is provided inside the water storage tank. The stirring rod facilitates the stirring of sludge in the sewage, avoids sludge sedimentation, and keeps the sludge in a suspended state.

[0041] The filter tank group 11 includes two filter tanks 11 arranged in parallel and located on both sides of the rotation center of the lever structure, an inlet pipe 15 connecting the filter tank 11 and the water storage tank, and an inlet valve 16 located on the inlet pipe 15. The lever structure includes a horizontal plate 30 axially connected to the support, a support rod 37 fixed to the bottom of the filter tank 11, and a middle rod 35 with both ends hinged to the horizontal plate 30 and the support rod 37 respectively. A guide sleeve 36 is fixed to the support rod 37 and slides along the height direction on the support. A guide block is provided on the side of the filter tank 11. The guide block and the guide sleeve 36 are both vertically slidable on the support along the height direction. A buffer spring 34 is provided at the lower end of the horizontal plate 30 and is set on the support. There are two buffer springs 34, which are located on both sides of the rotation center of the horizontal plate 30. When the filter tank is at the upper end, the buffer spring does not contact the horizontal plate. When the horizontal plate is lowered to a certain height, the buffer spring contacts the horizontal plate and plays a buffering role.

[0042] The filter tank 11 is provided with a filter plate 18 having a plurality of filter holes. A filter rod 12 is connected to the filter plate 18 and extends to the top of the filter tank 11. A telescopic motor is connected to the upper end of the filter rod 12, and the telescopic motor drives the filter rod 12 to move along the height direction.

[0043] The bottom of the filter tank 11 is connected to a drain pipe 32 equipped with a drain valve 33. A transfer tank 4 is also provided between the drain pipe 32 and the tank body 2. The transfer tank 4 is connected to the drain pipe 32. A level gauge is provided inside the transfer tank 4. An air outlet is provided on the transfer tank 4. An air suction pump is provided on the pipe connecting the transfer tank 4 and the tank body 2 for sucking out the sewage in the transfer tank 4.

[0044] The side of the filter tank 11 is also provided with a limiting structure 14 to restrict the movement of the filter tank 11. The limiting structure 14 includes a limiting rod 71 that slides on the limiting plate 74 and extends into the filter tank 11. A baffle 72 is fixed to the limiting rod 71. A limiting spring 73 is provided between the baffle 72 and the limiting plate 74 to push the limiting rod 71 to move into the filter tank 11. The end face of the limiting rod 71 is spherical. The filter tank 11 is provided with a groove 13 that is adapted to the spherical surface of the limiting rod 71 and allows the limiting rod 71 to be inserted. Grooves 13 are provided on the two opposite outer surfaces of the filter tank 11. The grooves 13 are correspondingly arranged with the limiting rod 71. During use, the limiting rod 71 is always pressed against the filter tank 11.

[0045] The filter tank 11 is also connected to a pull rope 6. The pull rope 6 passes around a fixed pulley 61 and through a fixed plate 62, and is connected to a trigger rod 65. A drain switch 64, which is electrically connected to a drain valve 33, is provided between the trigger rod 65 and the fixed plate 62. The fixed plate 62 is also provided with an intermediate spring 63 that connects the fixed plate 62 and the trigger rod 65 and drives the trigger rod 65 away from the fixed plate 62. A telescopic rod is provided inside the intermediate spring 63. The two ends of the telescopic rod are connected to the fixed plate 62 and the trigger rod 65, respectively. The pull rope 6 passes through the telescopic rod and is connected to the trigger rod 65.

[0046] The moving front ends of the two trigger rods 65 are respectively equipped with a forward switch 66 and a reverse switch to drive the stepper motor to rotate forward and reverse. The output end of the stepper motor is insulated and connected to a switch 5. The circuits of the two liquid inlet valves 16 are connected in parallel and are connected in series with the switch 5.

[0047] The filter tank 11 is also provided with a suction port 17, which is connected to a suction pump. The suction button 70 switch, which is electrically connected to the suction pump, is located in one of the grooves 13.

[0048] The filter tank 11 is equipped with a one-way valve at the liquid inlet and a ventilation valve at the top of the filter tank 11. The ventilation valve is a one-way ventilation valve.

[0049] Specifically, the suction button 70 of the suction pump, the drain switch 64 of the drain valve 33, the forward switch 66, and the reverse switch are all action buttons. That is, when the button is pressed, the circuit is connected; when the button is released, the circuit is closed. Each time the current is turned on, the stepper motor rotates by a certain angle. The inlet pipe 15 and the drain pipe 32 are both flexible hoses.

[0050] A method for using a decentralized rural domestic sewage treatment system includes the following steps:

[0051] In rural areas, sewage first enters a storage tank. A filter screen is installed at the inlet of the storage tank to filter out larger particles. At this time, the sewage in the storage tank includes wastewater and sludge. Then, the sludge is distributed to several filter tanks (11 groups) for filtering out smaller particles.

[0052] In a set of 11 filter tanks, two filter tanks 11 are arranged side by side. The inlet valve 16 on the left is open and the inlet valve 16 on the right is closed. Wastewater enters the filter tank 11 on the left through the inlet pipe 15. At the same time, the telescopic motor drives the filter plate 18 to move up and down, thereby adjusting the position of the wastewater washing on the filter plate 18. This makes full use of the filter plate 18 while preventing sludge from depositing on the filter plate 18 and keeping the sludge in a suspended state to prevent sludge deposition.

[0053] As the filter plate 18 moves up and down, the particulate matter remains on the filter plate 18, while the sludge and wastewater enter the lower end of the filter plate 18. As the wastewater continues to enter, the left filter tank descends. After descending to a certain height, the horizontal plate 30 presses against the buffer spring 34, which acts as a buffer. When the left filter tank 11 descends to the drainage position, the limiting rod 71 of the limiting device is inserted into the groove 13. At this time, the pull rope 6 drives the trigger rod 65 to move backward and trigger the drain switch 64. The drain valve 33 opens, and the wastewater on the left enters the middle tank. At the same time, the limiting rod 71 triggers the suction pump and runs for a certain period of time to suck away the particulate matter on the filter plate 18.

[0054] When the left filter tank 11 reaches the drainage position, the right filter tank 11 reaches the liquid inlet position under the action of the horizontal plate 30. At this time, under the action of the middle spring 63, the right trigger rod 65 contacts the reverse switch to trigger the stepper motor to reverse, so that the circuit of the switch knife 5 is disconnected from the circuit of the left liquid inlet valve 16, and the circuit of the right liquid inlet valve 16 is connected, thereby closing the left liquid inlet valve 16 and opening the right liquid inlet valve 16, so that the sewage flows into the right filter tank 11, thereby achieving uninterrupted filtration of wastewater.

[0055] As the sewage in the left filter tank 11 flows out, the sewage in the right filter tank 11 enters. As the weight of the right filter tank 11 gradually increases, the force of the horizontal plate 30 on the left filter tank 11 gradually increases. When this force overcomes the resistance of the limit rod 71 on the filter tank 11, the left filter tank 11 moves upward. At this time, the suction pump stops working. At this time, there will be some residue in the left filter tank 11. As the sewage continues to enter the right filter tank 11, the right filter tank 11 descends and the left filter tank 11 rises, thus repeating the process to filter the sewage.

[0056] The filtered wastewater enters the transfer tank 4, and then enters the tank body 2. After passing through the anaerobic fermentation zone 21, the aerobic fermentation zone 22, and the packing purification zone 23 in the tank body 2, it finally enters the water storage zone 24, thereby achieving the treatment of wastewater.

[0057] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. A decentralized rural domestic sewage treatment system, characterized in that: The system includes a water storage tank, a group of filter tanks (11) connected to the water storage tank, and a tank body (2) connected to the filter tanks (11). The tank body (2) is provided with an anaerobic fermentation zone (21), an aerobic fermentation zone (22), a packing purification zone (23), and a water storage zone (24) arranged in sequence. The filter tank (11) group includes two filter tanks (11) arranged in parallel and located on both sides of the rotation center of the lever structure, an inlet pipe (15) connecting the filter tanks (11) and the water storage tank, and a liquid inlet pipe (15) located at the inlet. The filter tank (11) is provided with a liquid inlet valve (16), a filter plate (18) with several filter holes is provided inside the filter tank (11), a filter rod (12) is connected to the filter plate (18) and extends to the top of the filter tank (11) with a seal, a suction port (17) is also provided on the filter tank (11), a drain pipe (32) with a drain valve (33) is connected to the bottom of the filter tank (11), and a limiting structure (14) for restricting the movement of the filter tank (11) is also provided on the side of the filter tank (11). The upper end of the filter rod (12) is connected to a telescopic motor; The lever structure includes a horizontal plate (30) axially connected to the bracket, a support rod (37) fixed to the bottom of the filter tank (11), and a middle rod (35) with both ends respectively hinged to the horizontal plate (30) and the support rod (37). A guide sleeve (36) that slides along the height direction on the bracket is fixed to the support rod (37). The filter tank (11) is also connected to a pull rope (6). The pull rope (6) passes around the fixed pulley (61) and through the fixed plate (62) and is connected to a trigger rod (65). A drain switch (64) electrically connected to the drain valve (33) is provided between the trigger rod (65) and the fixed plate (62). The fixed plate (62) is also provided with an intermediate spring (63) that connects the fixed plate (62) and the trigger rod (65) and drives the trigger rod (65) away from the fixed plate (62). The moving front ends of the two trigger rods (65) are respectively provided with a forward switch (66) and a reverse switch that drive the stepper motor to rotate forward and reverse. The output end of the stepper motor is insulated and connected to a switch knife (5). The circuits of the two inlet valves (16) are connected in parallel and are connected in series with the switch knife (5). The limiting structure (14) includes a limiting rod (71) that slides on the limiting plate (74) and extends toward the filter tank (11). A baffle (72) is fixedly connected to the limiting rod (71). A limiting spring (73) is provided between the baffle (72) and the limiting plate (74) to push the limiting rod (71) toward the filter tank (11). The end face of the limiting rod (71) is spherical. The filter tank (11) is provided with a groove (13) that is adapted to the spherical surface of the limiting rod (71) and allows the limiting rod (71) to be inserted. Grooves (13) are provided on the two opposite outer surfaces of the filter tank (11). The grooves (13) are correspondingly provided with the limiting rod (71). A transfer tank (4) is also provided between the drain pipe (32) and the tank body (2). The transfer tank (4) is connected to the drain pipe (32). A level gauge is provided inside the transfer tank (4). An air outlet is provided on the transfer tank (4).

2. The decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The lower end of the horizontal plate (30) is provided with a buffer spring (34) that extends upward and is corresponding to the filter tank.

3. The decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The suction port (17) is connected to a suction pump, and the suction button (70) switch, which is electrically connected to the suction pump, is located in one of the grooves (13).

4. The decentralized rural domestic sewage treatment system according to claim 3, characterized in that: A one-way valve is provided at the inlet of the filter tank (11), and an air exchange valve is also provided at the top of the filter tank (11).

5. The method of using the decentralized rural domestic sewage treatment system according to claim 4, characterized in that, Includes the following steps: The sewage in the rural area first enters the water storage tank. A filter screen is set at the inlet of the water storage tank to filter larger particles. At this time, the sewage in the water storage tank includes wastewater and sludge. Then, the sludge will be distributed to several filter tanks (11) for filtering small particles. In a set of filter tanks (11), two filter tanks (11) are arranged side by side. The inlet valve (16) on the left is open and the inlet valve (16) on the right is closed. Sewage enters the filter tank (11) on the left through the inlet pipe (15). At the same time, the telescopic motor drives the filter plate (18) to move up and down, thereby adjusting the position of the sewage on the filter plate (18). While making full use of the filter plate (18), the sludge is prevented from being deposited on the filter plate (18), and the sludge is kept in a suspended state to prevent sludge deposition. As the filter plate (18) moves up and down, the particulate matter remains on the filter plate (18), while the sludge and wastewater enter the lower end of the filter plate (18). As the wastewater continues to enter, the filter tank on the left side descends. After descending to a certain height, the horizontal plate (30) presses against the buffer spring (34), which acts as a buffer. When the filter tank (11) on the left side descends to the drainage position, the limiting rod (71) of the limiting device is inserted into the groove (13). At this time, the pull rope (6) drives the trigger rod (65) to move backward and trigger the drain switch (64). The drain valve (33) opens, and the wastewater on the left side enters the middle tank. At the same time, the limiting rod (71) triggers the suction pump and runs for a certain period of time to suck away the particulate matter on the filter plate (18). When the left filter tank (11) reaches the drainage position, the right filter tank (11) reaches the liquid inlet position under the action of the horizontal plate (30). At this time, under the action of the middle spring (63), the right trigger rod (65) contacts the reverse switch to trigger, causing the stepper motor to reverse, causing the circuit of the switch knife (5) to disconnect from the circuit of the left liquid inlet valve (16), and the circuit of the right liquid inlet valve (16) to connect, thereby closing the left liquid inlet valve (16) and opening the right liquid inlet valve (16), so that the sewage flows into the right filter tank (11), thereby achieving uninterrupted filtration of wastewater; As the sewage in the left filter tank (11) flows out, the sewage in the right filter tank (11) enters. As the weight of the right filter tank (11) gradually increases, the force of the horizontal plate (30) on the left filter tank (11) gradually increases. When this force overcomes the resistance of the limit rod (71) on the filter tank (11), the left filter tank (11) moves upward. At this time, the suction pump stops working. At this time, there will be some residue in the left filter tank (11). As the sewage continues to enter the right filter tank (11), the right filter tank (11) descends and the left filter tank (11) rises. This process is repeated to filter the sewage. The filtered wastewater enters the transfer tank (4), and then enters the tank body (2) through the transfer tank (4). After passing through the anaerobic fermentation zone (21), the aerobic fermentation zone (22), and the packing purification zone (23) in the tank body (2), it finally enters the water storage zone (24), thereby achieving the treatment of wastewater.

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