A circulating treatment and utilization device for rural domestic sewage

Abstract

The application relates to the sewage treatment technical field and discloses a circulating treatment and utilization device for rural domestic sewage, which comprises multiple purification units and a treatment center. Each purification unit is connected with a sewage discharge end of each household, multiple adjacent purification units share one treatment center, the purification unit comprises a pretreatment bin and a purification bin, the bin bodies of the two are provided with circulating heating cavities, sewage first enters the pretreatment bin, is subjected to preliminary anaerobic decomposition and homogenization, then enters the purification bin for further degradation and purification, each purification unit is provided with a heating assembly, heat is generated by burning marsh gas to keep the environmental temperature in the purification unit within a temperature range suitable for the survival of bacteria. The treatment center centrally collects the marsh gas generated by each household purification unit, and distributes the use of the marsh gas according to actual conditions, which not only avoids the problem that the purification unit is damaged by low temperature, but also guarantees the activity of the bacteria in the purification unit, and further improves the treatment efficiency of the sewage.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a device for the recycling and treatment of rural domestic wastewater. Background Technology

[0002] In rural areas, as living standards improve, the amount of domestic sewage generated is increasing daily, but existing sewage treatment facilities have many drawbacks.

[0003] Traditional three-compartment septic tanks suffer from unstable treatment performance and poor adaptability to water volume. They struggle to maintain effective treatment when faced with fluctuations in sewage volume and have low shock resistance, easily affected by changes in sewage quality and quantity, leading to decreased treatment efficiency. The quality of septic tank products on the market varies greatly, and prices fluctuate significantly. In cold northern regions, they generally have poor frost resistance, making them prone to damage in low-temperature environments and failing to meet the needs of rural domestic sewage treatment. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a device for the recycling and treatment of rural domestic sewage, which solves the problems of poor treatment efficiency and poor frost resistance in existing rural domestic sewage treatment methods.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a rural domestic sewage recycling treatment and utilization device, comprising multiple purification units and a treatment center. Each purification unit is connected to the sewage discharge end of each household, and multiple adjacent purification units share a single treatment center. Each purification unit includes a pretreatment chamber and a purification chamber, both of which are equipped with a circulating heating chamber. Sewage first enters the pretreatment chamber for preliminary anaerobic decomposition and homogenization, and then enters the purification chamber for further degradation and purification. Each purification unit is equipped with a heating component, which uses the heat generated by burning biogas to maintain the ambient temperature within the purification unit within a temperature range suitable for the survival of microorganisms. The treatment center includes a biogas collection unit, a biogas storage unit, and a biogas distribution unit. The biogas collection unit is connected to the exhaust port of the pretreatment chamber through a biogas collection pipe to collect the gas discharged from the pretreatment chamber and inject the collected gas into the biogas storage unit for storage. The biogas distribution unit is connected to the heating component and the aeration end of the pretreatment chamber, respectively, to quantitatively distribute the biogas stored in the biogas storage unit to the heating component and the aeration end of the pretreatment chamber.

[0006] Preferably, the purification unit is buried below the freezing line, and an insulation layer and a pressure-resistant layer are added to the outside of the purification unit.

[0007] Preferably, the pretreatment chamber includes a sewage chamber and a regulating chamber, with a partition between them and an overflow port at the top of the partition. The upper part of the sewage chamber and the regulating chamber is a gas collection chamber, and the bottom of both the sewage chamber and the regulating chamber is equipped with an aeration unit. Domestic sewage enters the sewage chamber and is treated by anaerobic fermentation to treat parasite eggs and degrade organic matter. As the water level rises, it enters the regulating chamber through the overflow port for homogenization and regulation. Some biogas enters the bottom of the sewage chamber and the regulating chamber through the aeration unit. As the biogas rises, it stirs the sewage inside both chambers and mixes with the newly generated biogas before entering the biogas collection unit through the biogas collection pipe.

[0008] Preferably, a portion of the biogas collection pipe is located above the frost line and is equipped with a water collector for collecting water generated by biogas condensation.

[0009] Preferably, the purification chamber includes a multi-stage degradation chamber and a clear water chamber, with a partition 2 between them and an overflow port 2 at the top of the partition 2. The bottom of the multi-stage degradation chamber and the upper part of the regulating chamber are connected by a pipe. The multi-stage degradation chamber adopts a mud-film symbiosis process to form an anaerobic and aerobic alternating degradation structure in the multi-stage degradation chamber, which performs biodegradation and denitrification on the homogenized wastewater. The clear water chamber adopts a static sedimentation process and is equipped with an immersion disinfection tank to disinfect the settled clear water by ultraviolet disinfection.

[0010] Preferably, the heating assembly includes a circulation unit and a biogas combustion heating unit. Part of the biogas is distributed to the biogas combustion heating unit for combustion, and water is heated by the biogas combustion heating unit and then transported to the circulation heating chamber through the circulation unit to form a circulation heating mode.

[0011] Preferably, each anoxic zone and aerobic zone in the multi-stage degradation chamber is also equipped with an aeration unit. The aeration unit in the anoxic zone of the multi-stage degradation chamber is connected to the exhaust end of the biogas combustion heating unit. The exhaust gas after biogas combustion enters the anoxic zone of the multi-stage degradation chamber. The aeration unit in the aerobic zone of the multi-stage degradation chamber is connected to the air supply equipment, and outside air enters the aerobic zone of the multi-stage degradation chamber.

[0012] This invention provides a device for the recycling and treatment of rural domestic sewage. It has the following beneficial effects:

[0013] This invention centrally collects biogas generated by each household's purification unit through a processing center and allocates the biogas usage according to actual conditions. On the one hand, the biogas is used to aerate and stir the sewage in the pretreatment chamber, thereby driving the flow and mixing of the sewage, allowing pollutants, microorganisms, and added treatment agents in the sewage to come into more thorough contact and react, thus improving sewage treatment efficiency. On the other hand, the heat generated by burning biogas through heating components is circulated in the circulating heating chamber, keeping the ambient temperature inside the purification unit within a temperature range suitable for the survival of microorganisms. This not only avoids the problem of the purification unit being damaged by low temperatures, but also ensures the activity of the microorganisms in the purification unit, further improving the sewage treatment efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the system structure of a rural domestic sewage recycling treatment and utilization device according to the present invention;

[0015] Figure 2 This is a schematic diagram of the system structure of the processing center in this invention;

[0016] Figure 3 This is a schematic diagram of the system structure of the purification unit in this invention;

[0017] Figure 4 This is a schematic diagram of the system structure of the heating component in this invention.

[0018] The components are as follows: 10. Purification unit; 101. Pretreatment chamber; 1011. Manure chamber; 1012. Regulating chamber; 1013. Partition 1; 1014. Overflow port 1; 1015. Gas collection chamber; 102. Purification chamber; 1021. Multi-stage degradation chamber; 1022. Clean water chamber; 1023. Partition 2; 1024. Overflow port 2; 103. Circulating heating chamber; 20. Treatment center; 201. Biogas collection unit; 202. Biogas storage unit; 203. Biogas distribution unit; 204. Biogas collection pipe; 30. Heating component; 301. Circulation unit; 302. Biogas combustion heating unit. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see the appendix Figure 1 - Appendix Figure 4This invention provides a rural domestic sewage recycling treatment device, comprising multiple purification units 10 and a treatment center 20. Each purification unit 10 is connected to the sewage discharge end of each household. Multiple adjacent purification units 10 share a single treatment center 20. Each purification unit 10 includes a pretreatment chamber 101 and a purification chamber 102, both of which are equipped with a circulating heating chamber 103. Sewage first enters the pretreatment chamber 101 for preliminary anaerobic decomposition and homogenization, and then enters the purification chamber 102 for further degradation and purification. Each purification unit 10 is equipped with a heating component 30, which generates heat by burning biogas to power the purification unit 101. The ambient temperature within 0 is maintained within the temperature range suitable for the survival of the microorganisms. The treatment center 20 includes a biogas collection unit 201, a biogas storage unit 202, and a biogas distribution unit 203. The biogas collection unit 201 is connected to the exhaust port of the pretreatment chamber 101 through a biogas collection pipe 204 to collect the gas discharged from the pretreatment chamber 101 and inject the collected gas into the biogas storage unit 202 for storage. The biogas distribution unit 203 is connected to the heating component 30 and the aeration end of the pretreatment chamber 101 respectively, and is used to quantitatively distribute the biogas stored in the biogas storage unit 202 to the heating component 30 and the aeration end of the pretreatment chamber 101.

[0021] The rural domestic sewage recycling system mainly consists of multiple purification units 10 and a treatment center 20. In terms of layout, each purification unit 10 is precisely connected to the sewage discharge end of each household, and multiple adjacent purification units 10 will rely on a single treatment center 20 to achieve centralized and large-scale treatment.

[0022] The purification unit 10 is further subdivided into a pretreatment chamber 101 and a purification chamber 102. Both chambers are uniquely designed with a circulating heating chamber 103. The entire wastewater treatment process is as follows: wastewater first flows into the pretreatment chamber 101, where preliminary anaerobic decomposition and homogenization are initiated. During this process, the complex organic matter in the wastewater is slowly decomposed by anaerobic microorganisms in an anaerobic environment, and the various components gradually become homogenized. After preliminary treatment, the wastewater then enters the purification chamber 102 for further degradation and deep purification. To ensure stable system operation, each purification unit 10 is equipped with a heating component 30. Its operating principle is to generate heat by burning biogas, and then cleverly utilize the heat in the circulating heating chamber 103, keeping the interior of the purification unit 10 within a suitable temperature range for the survival and reproduction of microorganisms. This is crucial for wastewater treatment, as it avoids the risk of damage to the purification unit 10 due to low temperatures and ensures the activity of the microorganisms. At the same time, the utilization of biogas also plays a role in energy conservation and emission reduction, reducing the consumption of electrical energy. The processing center 20, serving as the hub of the entire system, encompasses a biogas collection unit 201, a biogas storage unit 202, and a biogas distribution unit 203. The biogas collection unit 201 is tightly connected to the exhaust port of the pretreatment chamber 101 via a biogas collection pipe 204. Its core function is to accurately collect the gas emitted from the pretreatment chamber 101 and then steadily inject the collected gas into the biogas storage unit 202 for storage. The biogas distribution unit 203 plays a crucial role in allocation. It is connected to both the heating component 30 and the aeration end of the pretreatment chamber 101, aiming to quantitatively distribute the biogas stored in the biogas storage unit 202 to the heating component 30 and the aeration end of the pretreatment chamber 101 according to actual needs.

[0023] In practical application, the treatment center 20 centrally collects the biogas produced by each household's purification unit 10 and flexibly allocates its use according to actual working conditions. This addresses the problem of insufficient biogas production per household. On one hand, the biogas is transported to the aeration end of the pretreatment chamber 101, where it aerates and stirs the wastewater. As the biogas bubbles rise in the wastewater, they powerfully drive its flow and mixing, allowing pollutants, microorganisms, and subsequently added treatment agents to come into comprehensive and deep contact and react, greatly improving wastewater treatment efficiency. On the other hand, the heat generated by the combustion of biogas in the heating component 30 establishes a stable heating circulation mode within the circulating heating chamber 103, ensuring a suitable temperature within the purification unit 10.

[0024] The treatment center 20 centrally collects the biogas produced by each household's purification unit 10 and allocates it according to actual needs. On the one hand, the biogas is used to aerate and stir the sewage in the pretreatment chamber 101, thereby driving the flow and mixing of the sewage. This allows pollutants, microorganisms, and added treatment agents in the sewage to come into more thorough contact and react, improving sewage treatment efficiency. On the other hand, the heat generated by burning the biogas through the heating component 30 is circulated and heated in the circulating heating chamber 103, keeping the ambient temperature inside the purification unit 10 within a temperature range suitable for the survival of microorganisms. This not only avoids the problem of the purification unit 10 being damaged by low temperatures but also ensures the activity of the microorganisms inside the purification unit 10, further improving the sewage treatment efficiency.

[0025] By centrally collecting and intelligently supplying biogas from multiple households, biogas is utilized rationally and efficiently. Furthermore, in practical construction, it can be connected to septic tanks in livestock farms and other facilities to centrally collect the large amounts of biogas produced, thus completely solving the problem of biogas shortage. In addition, clean energy sources such as solar energy can be used as a supplement when biogas is insufficient.

[0026] The purification unit 10 is buried below the freezing line, and an insulation layer and a pressure-resistant layer are added to the outside of the purification unit 10.

[0027] In terms of installation details, the purification unit 10 is buried below the frost line, and a heat insulation layer and a pressure-resistant layer are added to the outside of the purification unit 10. This design not only prevents the purification unit 10 from being corroded by low temperatures, but also enhances its pressure resistance, enabling it to operate stably for a long time in complex underground environments.

[0028] The pretreatment chamber 101 includes a sewage chamber 1011 and a regulating chamber 1012, with a partition 1013 between them. An overflow port 1014 is provided at the top of the partition 1013. The upper part of the sewage chamber 1011 and the regulating chamber 1012 is a gas collection chamber 1015, and both the sewage chamber 1011 and the regulating chamber 1012 are equipped with aeration units at the bottom. Domestic sewage enters the sewage chamber 1011 and is treated by anaerobic fermentation to treat parasite eggs and degrade organic matter. As the water level rises, it enters the regulating chamber 1012 through the overflow port 1014 for homogenization and regulation. Some biogas enters the bottom of the sewage chamber 1011 and the regulating chamber 1012 through the aeration units. As the biogas rises, it stirs the sewage inside the two chambers and mixes with the newly generated biogas before entering the biogas collection unit 201 through the biogas collection pipe 204.

[0029] The pretreatment chamber 101 is further subdivided into a sewage chamber 1011 and a regulating chamber 1012, separated by a partition 1013, with an overflow outlet 1014 precisely positioned at the top of the partition 1013. A gas collection chamber 1015 is constructed above the interior of both the sewage chamber 1011 and the regulating chamber 1012, and an aeration unit is installed at the bottom of both. After domestic sewage flows into the sewage chamber 1011, an anaerobic fermentation process begins, specifically targeting parasite eggs in the sewage while gradually degrading organic matter. As the sewage level gradually rises, it flows smoothly into the regulating chamber 1012 through the overflow outlet 1014 for homogenization. During this process, some biogas is injected into the bottom of both the sewage chamber 1011 and the regulating chamber 1012 by the aeration unit. As the biogas rises, it not only stirs the sewage but also mixes with the newly generated biogas, finally flowing smoothly into the biogas collection unit 201 through the biogas collection pipe 204.

[0030] Part of the biogas collection pipe 204 is located above the frost line and is equipped with a water collector to collect the water produced by biogas condensation.

[0031] Because part of the biogas collection pipe 204 is located above the frost line, when biogas mixed with water vapor flows in the biogas collection pipe 204, the water vapor condenses under the influence of cold weather, forming liquefied water that enters the water collector. The water in the water collector can be either transported back to the pretreatment chamber 101 or transported to the purification chamber 102.

[0032] The purification chamber 102 includes a multi-stage degradation chamber 1021 and a clear water chamber 1022, with a partition 1023 between them and an overflow port 1024 at the top of the partition 1023. The bottom of the multi-stage degradation chamber 1021 is connected to the upper part of the regulating chamber 1012 through a pipe. The multi-stage degradation chamber 1021 adopts a mud-film symbiosis process, forming an anaerobic and aerobic alternating degradation structure in the multi-stage degradation chamber 1021 to biodegrade and denitrify the homogenized wastewater. The clear water chamber 1022 adopts a static sedimentation process and is equipped with an immersion disinfection tank, which uses ultraviolet disinfection to disinfect the settled clear water.

[0033] The purification chamber 102 consists of a multi-stage degradation chamber 1021 and a clear water chamber 1022, separated by a partition 1023. An overflow outlet 1024 is located at the top of the partition 1023. The bottom of the multi-stage degradation chamber 1021 is seamlessly connected to the upper part of the regulating chamber 1012 via a pipe. The multi-stage degradation chamber 1021 employs an advanced sludge-film symbiosis process, thereby constructing an alternating anoxic and aerobic degradation structure within the chamber, enabling efficient biological degradation and precise denitrification of the homogenized wastewater. The clear water chamber 1022 uses a static sedimentation process and includes a submerged disinfection tank, fully utilizing ultraviolet disinfection to thoroughly disinfect the settled clear water, ensuring that the effluent meets quality standards.

[0034] The heating assembly 30 includes a circulation unit 301 and a biogas combustion heating unit 302. Part of the biogas is distributed to the biogas combustion heating unit 302 for combustion. After being heated by the biogas combustion heating unit 302, the water is transported to the circulation heating chamber 103 through the circulation unit 301 to form a circulation heating mode.

[0035] Each anoxic and aerobic zone within the multi-stage degradation chamber 1021 is also equipped with an aeration unit. The aeration unit in the anoxic zone of the multi-stage degradation chamber 1021 is connected to the exhaust end of the biogas combustion heating unit 302, and the exhaust gas after biogas combustion enters the anoxic zone within the multi-stage degradation chamber 1021. The aeration unit in the aerobic zone of the multi-stage degradation chamber 1021 is connected to the air supply equipment, and outside air enters the aerobic zone within the multi-stage degradation chamber 1021.

[0036] The heating component 30 consists of a circulation unit 301 and a biogas combustion heating unit 302. A portion of the biogas is precisely distributed to the biogas combustion heating unit 302 for combustion. Water, after being heated by the biogas combustion heating unit 302, is rapidly transported to the circulation heating chamber 103 through the circulation unit 301, successfully establishing a circulation heating mode and ensuring stable temperature within the purification unit 10. Simultaneously, each anoxic and aerobic zone within the multi-stage degradation chamber 1021 is equipped with an aeration unit. The aeration unit in the anoxic zone of the multi-stage degradation chamber 1021 is connected to the exhaust end of the biogas combustion heating unit 302, allowing the waste gas from biogas combustion to enter and be utilized in the anoxic zone of the multi-stage degradation chamber 1021. The aeration unit in the aerobic zone of the multi-stage degradation chamber 1021 is connected to an air supply device, ensuring smooth entry of outside air into the aerobic zone of the multi-stage degradation chamber 1021, providing sufficient oxygen for the microorganisms and ensuring the smooth progress of the biodegradation process.

[0037] Of course, the entire wastewater recycling system relies on the auxiliary operation of the control system. The control system adopts a fully automatic operation + unattended operation + remote real-time monitoring intelligent operation mode, connecting the wastewater treatment equipment in the area to the "Industrial Internet Digital Intelligent Centralized Management and Control Platform." Intelligent data acquisition equipment collects wastewater quality (such as COD, ammonia nitrogen, total phosphorus, etc.), water volume, and equipment operating status (such as pump speed, valve opening / closing status, aeration intensity, etc.) data in real time. Combined with local high-altitude (or high-temperature, plateau, etc.) climate and residents' water usage patterns, the system uses artificial intelligence and cloud computing analysis to develop optimal operating processes for each or multiple households. The remote control system drives the equipment to operate automatically based on the analysis results, achieving rural domestic wastewater treatment without human intervention throughout the entire process, maintaining optimal treatment status in a long-term stable manner. It also monitors biogas collection data in real time and plays a crucial role in accurately distributing biogas for its rational utilization. Furthermore, clean energy components such as solar panels can be added to supplement energy when biogas levels are insufficient.

[0038] Meanwhile, the system platform employs multi-dimensional data interaction and management: users can monitor the system in real time via mobile phones, computers, and other terminals, viewing information such as wastewater quality change curves, equipment operating parameter charts, and historical data records at any time. When the system malfunctions or water quality abnormalities occur, the terminal receives alarm notifications so that timely measures can be taken. Furthermore, the platform possesses powerful statistical analysis capabilities, enabling in-depth analysis of data such as total wastewater discharge, treatment efficiency, and energy consumption within the region. This provides scientific data-driven decision support for rural wastewater treatment planning and equipment optimization and upgrading, achieving digital, intelligent, and convenient operation and maintenance management.

[0039] The actual operating effect of the aforementioned rural domestic sewage recycling device was tested. The test method involved sampling the water quality at both the system's inlet and outlet, for a total of three samplings. The specific results are shown in the table below:

[0040] Sampling time: November 21, 2024

[0041]

[0042]

[0043] Sampling time: December 5, 2024

[0044]

[0045] Sampling time: December 16, 2024

[0046]

[0047]

[0048] Sampling time: January 8, 2025

[0049]

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A recycling and utilization device for rural domestic sewage, comprising multiple purification units (10) and a treatment center (20), characterized in that, Each purification unit (10) is connected to the sewage discharge end of each household. Multiple adjacent purification units (10) share a treatment center (20). Each purification unit (10) includes a pretreatment chamber (101) and a purification chamber (102). Both chambers are equipped with a circulating heating chamber (103). Sewage first enters the pretreatment chamber (101) for preliminary anaerobic decomposition and homogenization, and then enters the purification chamber (102) for further degradation and purification. Each purification unit (10) is equipped with a heating component (30). By burning biogas to generate heat, the ambient temperature inside the purification unit (10) is maintained within a temperature range suitable for the survival of bacteria. The center (20) includes a biogas collection unit (201), a biogas storage unit (202), and a biogas distribution unit (203). The biogas collection unit (201) is connected to the exhaust port of the pretreatment chamber (101) through a biogas collection pipe (204) to collect the gas discharged from the pretreatment chamber (101) and inject the collected gas into the biogas storage unit (202) for storage. The biogas distribution unit (203) is connected to the heating component (30) and the aeration end of the pretreatment chamber (101) respectively, and is used to quantitatively distribute the biogas stored in the biogas storage unit (202) to the heating component (30) and the aeration end of the pretreatment chamber (101). The pretreatment chamber (101) includes a sewage chamber (1011) and a regulating chamber (1012), with a partition (1013) between them. An overflow port (1014) is provided at the top of the partition (1013). An air collection chamber (1015) is located above both the sewage chamber (1011) and the regulating chamber (1012). An aeration unit is provided at the bottom of both the sewage chamber (1011) and the regulating chamber (1012). Domestic sewage enters the sewage chamber (1011)... 1011), Parasite eggs are treated by anaerobic fermentation and organic matter is degraded. As the water level rises, the overflow outlet (1014) enters the regulating chamber (1012) for homogenization. Some biogas enters the bottom of the manure tank (1011) and regulating chamber (1012) respectively from the aeration unit. As the biogas rises, it stirs the sewage inside the two chambers and mixes with the newly generated biogas before entering the biogas collection unit (201) through the biogas collection pipe (204). The purification chamber (102) includes a multi-stage degradation chamber (1021) and a clear water chamber (1022), with a partition plate (1023) between them and an overflow port (1024) at the top of the partition plate (1023). The bottom of the multi-stage degradation chamber (1021) is connected to the upper part of the regulating chamber (1012) through a pipe. The multi-stage degradation chamber (1021) adopts a mud-film symbiosis process to form an anaerobic and aerobic alternating degradation structure in the multi-stage degradation chamber (1021) to biodegrade and denitrify the homogenized sewage. The clear water chamber (1022) adopts a static sedimentation process and is equipped with an immersion disinfection tank to disinfect the settled clear water by ultraviolet disinfection. The heating component (30) includes a circulation unit (301) and a biogas combustion heating unit (302). Part of the biogas is distributed to the biogas combustion heating unit (302) for combustion. After the water is heated by the biogas combustion heating unit (302), it is transported to the circulation heating chamber (103) through the circulation unit (301) to form a circulation heating mode. Each anoxic and aerobic zone in the multi-stage degradation chamber (1021) is also equipped with an aeration unit. The aeration unit in the anoxic zone of the multi-stage degradation chamber (1021) is connected to the exhaust end of the biogas combustion heating unit (302). The exhaust gas after biogas combustion enters the anoxic zone in the multi-stage degradation chamber (1021). The aeration unit in the aerobic zone of the multi-stage degradation chamber (1021) is connected to the air supply equipment, and outside air enters the aerobic zone in the multi-stage degradation chamber (1021).

2. The rural domestic sewage recycling treatment and utilization device according to claim 1, characterized in that, The purification unit (10) is buried below the freezing line, and an insulation layer and a pressure-resistant layer are added to the outside of the purification unit (10).

3. The rural domestic sewage recycling treatment and utilization device according to claim 1, characterized in that, Part of the biogas collection pipe (204) is located above the frost line and is equipped with a water collector for collecting water generated by biogas condensation.

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