A distributed low-carbon and multi-quality treatment and resource system for rural domestic sewage

Abstract

The application discloses a kind of distributed rural domestic sewage low-carbon and resource system of quality treatment, it is related to wastewater treatment field, and its technical scheme main point is that septic tank, liquid fertilizer storage pool, sludge oil separation well, anaerobic biofilm pool and sewage purification module are provided with water inlet and overflow, and the height of each overflow is greater than or equal to the height of water inlet on the structure thereof.Specific bacteria and spherical filler are put into septic tank.Black water is connected to septic tank, kitchen wastewater is connected to sludge oil separation well, liquid overflowed from septic tank flows into liquid fertilizer storage pool, and water outlet of liquid fertilizer storage pool and sludge oil separation well and other grey water flow into anaerobic biofilm pool.Water outlet of anaerobic biofilm pool flows into sewage purification module.The application carries out different treatment on black water, kitchen wastewater and other grey water respectively, and the whole treatment process does not need power device, and the construction and operation difficulty is small, the cost is low, which is suitable for distributed treatment mode of rural domestic sewage treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and more specifically, to a decentralized, low-carbon, differentiated treatment and resource recovery system for rural domestic wastewater. Background Technology

[0002] Most rural areas lack dedicated sewage collection networks and sewage treatment systems, meaning that the vast majority of rural sewage is discharged directly without treatment, posing a significant threat to the ecological environment and safety.

[0003] Currently, rural domestic sewage treatment can be divided into three modes: centralized treatment, piped sewage treatment, and decentralized treatment. Piped sewage treatment involves collecting rural domestic sewage centrally and connecting it to a sewage treatment plant or nearby facilities for unified treatment. However, this mode is only suitable for villages with high population density, located close to towns (generally within 3km), and with terrain conditions conducive to gravity flow of sewage into urban sewage networks. Centralized treatment is suitable for rural areas where domestic sewage cannot be connected to sewage treatment plants or urban sewage trunk lines, requiring the construction of their own sewage treatment facilities. Centralized treatment equipment typically occupies a large area, and equipment and maintenance costs are high. Decentralized treatment is suitable for households in areas with abundant water systems, mountainous areas, or other areas where pipe network construction is difficult, or for sewage treatment of single or adjacent households in relatively remote villages. This is the main mode of rural domestic sewage treatment currently in use.

[0004] Rural wastewater can be divided into black water and grey water. Black water is collected from toilets and its main components are feces and urine. Grey water mainly includes kitchen wastewater, washing wastewater, shower wastewater, and other wastewater. Chinese invention patent CN111333274A provides a rural wastewater enhanced separation and integrated resource-based treatment device, which treats black water and grey water differently. However, this device requires power units such as motors, fans, return pumps, and peristaltic pumps, resulting in high construction and maintenance costs, making its implementation in decentralized treatment modes quite difficult. Summary of the Invention

[0005] To address the problems of existing rural sewage treatment devices having numerous power units, resulting in high construction and maintenance costs and difficulty in application to decentralized treatment models, this invention aims to provide a decentralized, low-carbon, differentiated treatment and resource recovery system for rural domestic sewage. This system includes a septic tank, a liquid fertilizer storage tank, a sedimentation and grease trap, an anaerobic biofilm tank, and a sewage purification module. At least one sewage purification module is provided, which can be at least one of a modular constructed wetland, a non-powered aerated trickling filter, or a non-powered sewage purification tank. Each of the septic tank, liquid fertilizer storage tank, sedimentation and grease trap, anaerobic biofilm tank, and sewage purification module is equipped with an inlet and an overflow outlet, with the height of each overflow outlet being greater than or equal to the height of the inlet on its corresponding structure.

[0006] The septic tank's inlet connects to black water, the grease trap's inlet connects to kitchen wastewater, and all grey water (excluding kitchen wastewater) connects to the anaerobic biofilm tank's inlet. The septic tank's overflow connects to the liquid fertilizer storage tank's inlet. The liquid fertilizer storage tank has an opening at the top, and its overflow outlets, along with the grease trap's overflow outlet, connect to the anaerobic biofilm tank's inlet. The anaerobic biofilm tank's overflow outlet connects to the inlets of all wastewater treatment modules. Liquid overflowing from all wastewater treatment modules is discharged into water bodies or farmland.

[0007] The wastewater treatment modules used in wastewater control areas are modular constructed wetlands.

[0008] Set a groundwater level threshold. In non-sewage-controlled areas, where the groundwater level is less than or equal to the groundwater level threshold, the wastewater treatment module used is a non-powered aerated trickling filter. In non-sewage-controlled areas, where the groundwater level is greater than the groundwater level threshold, the wastewater treatment module used is a non-powered wastewater treatment tank.

[0009] The present invention is further configured such that fermentation agents and spherical packing materials are added to the septic tank.

[0010] The invention is further configured such that the black water originates from a toilet with a single flush volume of less than 1L. The dosage of the fermentation agent is 300-500mL / m³. 3 The packing volume of spherical packing material is 50%-80% of the fermentation space volume of the septic tank.

[0011] The present invention is further configured such that the black water stays in the septic tank for no less than 30 days.

[0012] The present invention is further configured such that the microbial carrier placed in the anaerobic biofilm tank is a spherical packing material. The stacking volume of the spherical packing material is 50%-80% of the volume of the anaerobic biofilm tank.

[0013] The present invention is further configured such that: the packing material of the non-powered sewage purification tank, the packing material of the non-powered blow-drip filter, and the substrate of the modular constructed wetland all include adsorption filter media, wherein the adsorption filter media includes at least one of nitrogen adsorption filter media and phosphorus adsorption filter media.

[0014] The present invention is further configured such that the packing material of the non-powered sewage purification tank also includes spherical packing material.

[0015] The present invention is further configured such that the substrate of the modular constructed wetland also includes gravel.

[0016] The invention is further configured to include a regulating tank, which has a top opening, an inlet, and an overflow outlet. The height of the overflow outlet of the regulating tank is greater than or equal to the height of the inlet of the regulating tank. The overflow outlets of all wastewater purification modules are connected to the inlet of the regulating tank, and the liquid overflowing from the overflow outlet of the regulating tank is discharged into water bodies or farmland.

[0017] The invention is further configured to include a water pump, which is used to pump the liquid in the storage tank out of the storage tank from the top opening of the storage tank for utilization or discharge when the water in the storage tank cannot overflow.

[0018] In summary, the present invention has the following advantages over the prior art: the present invention treats black water, kitchen wastewater and other grey water wastewater differently, and the entire treatment process does not require a power device. The wastewater flows between the septic tank, liquid fertilizer storage tank, sedimentation oil separator, anaerobic biofilm tank and wastewater purification module only through liquid overflow. The construction and operation are simple and low-cost, and it is suitable for decentralized treatment mode of rural domestic sewage treatment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of Example 1.

[0020] In the diagram: 1. Toilet; 2. Toilet drain pipe; 3. Septic tank; 31. Black water inlet pipe; 32. Black water connecting pipe; 33. Black water overflow pipe; 4. Liquid fertilizer storage tank; 5. Overflow drain pipe; 6. Grey water inlet pipe; 7. Sediment separator; 8. Anaerobic biofilm tank; 9. Non-powered sewage purification tank; 91. Sewage inlet pipe; 92. Sewage connecting pipe; 93. Sewage overflow pipe; 10. Regulating tank; 11. Water pump; 12. Non-powered pump Trickling filter; 121. Trickling filter inlet pipe; 122. Water distributor; 123. Air outlet pipe; 124. Air inlet pipe; 125. Trickling filter overflow pipe; 13. Modular constructed wetland; 131. Wetland inlet pipe; 132. Wetland connecting pipe; 133. Wetland overflow pipe; 14. Fermentation agent periodic dosing device; 15. Spherical packing material; 16. Nitrogen adsorption filter media; 17. Phosphorus adsorption filter media; 18. Plants; 19. Solar power supply device. Detailed Implementation

[0021] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all 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 invention.

[0022] It should be noted that the terms "center", "upper", "lower", "horizontal", "left", "right", "front", "rear", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0023] Example 1

[0024] like Figure 1 As shown, this embodiment provides a decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system, which includes a septic tank 3, a liquid fertilizer storage tank 4, a sedimentation and grease trap 7, an anaerobic biofilm tank 8, and a sewage purification module. At least one sewage purification module is provided, which is at least one of a modular constructed wetland 13, a non-powered aerated drip filter 12, and a non-powered sewage purification tank 9. The septic tank 3, liquid fertilizer storage tank 4, sedimentation and grease trap 7, anaerobic biofilm tank 8, and sewage purification module are all provided with inlets and overflows, and the height of each overflow is greater than or equal to the height of the inlet on its corresponding structure.

[0025] The inlet of septic tank 3 is connected to black water. The inlet of grease trap 7 is connected to kitchen wastewater. All grey water, except for kitchen wastewater, is connected to the inlet of anaerobic biofilm tank 8. The overflow outlet of septic tank 3 is connected to the inlet of liquid fertilizer storage tank 4, which has an open top. The overflow outlets of liquid fertilizer storage tank 4 and grease trap 7 are connected to the inlet of anaerobic biofilm tank 8. The overflow outlet of anaerobic biofilm tank 8 is connected to the inlet of all wastewater treatment modules, and the liquid overflowing from all wastewater treatment modules is discharged into water bodies or farmland.

[0026] This embodiment treats black water, kitchen wastewater, and other grey water wastewater differently, and the entire treatment process requires no power unit. Wastewater flows between the septic tank 3, liquid fertilizer storage tank 4, sludge-oil separator 7, anaerobic biofilm tank 8, and wastewater purification module solely through liquid overflow. Construction and operation are simple and cost-effective, making it suitable for decentralized treatment models in rural domestic wastewater treatment. Farmers can use manual scooping or pumping to apply the manure from the liquid fertilizer storage tank 4 to the fields on-site. The portion that cannot be used on-site is discharged into the anaerobic biofilm tank 8 through the overflow outlet of the liquid fertilizer storage tank 4.

[0027] In addition, this embodiment also provides targeted sewage purification modules for different scenarios, taking into account the sewage management situation and groundwater level in the region.

[0028] Specifically, in wastewater control areas, the wastewater treatment module used is a modular constructed wetland 13. These wastewater control areas are those with wastewater management policies. The modular constructed wetland 13 primarily relies on the natural action of plants 18 and microorganisms to remove pollutants from wastewater, exhibiting low dependence on chemical agents, producing fewer harmful byproducts, and posing a low risk of secondary pollution. Simultaneously, a groundwater level threshold is set. In non-wastewater control areas, where the groundwater level is less than or equal to the groundwater level threshold, the wastewater treatment module used is a non-powered aerated drip filter 12. The non-powered aerated drip filter 12 increases the contact between wastewater and air through natural ventilation and gravity, accelerating the wastewater oxidation and decomposition process, improving wastewater treatment efficiency, and promoting water resource recycling. It is suitable for areas with low groundwater levels and scarce water resources. In non-wastewater control areas, where the groundwater level is greater than the groundwater level threshold, the wastewater treatment module used is a non-powered wastewater purification tank 9. The non-powered wastewater purification tank 9 mainly treats wastewater through filtration and sedimentation, featuring a simple structure, easy maintenance, and low cost.

[0029] Specifically, fermentation agents and spherical packing material 15 are placed in the septic tank 3. The microorganisms in the fermentation agents are used to treat the fecal waste in a harmless manner, and the spherical packing material 15 can provide an attachment carrier for the microorganisms, further accelerating the harmless treatment of solid pollutants in the black water.

[0030] Specifically, the septic tank 3 is divided into multiple interconnected compartments. At least one compartment contains fermentation agents and spherical packing material 15, with the spherical packing material 15 occupying 50%-80% of the compartment's volume. This multi-compartment septic tank 3 increases the residence time of black water within it, improving the black water purification effect. The connecting openings between adjacent compartments are staggered to avoid short-circuiting. In this embodiment, the septic tank 3 consists of three interconnected compartments. The first two compartments contain fermentation agents and spherical packing material 15, and the top of the last compartment has an openable / closable access port for dispensing liquid fertilizer.

[0031] Specifically, the black water originates from toilet 1, where the single flush volume is less than 1L. The dosage of fermentation agent is 300-500mL / m3. The stacking volume of the spherical packing material 15 is 50%-80% of the fermentation space volume of the septic tank 3.

[0032] Specifically, the black water must remain in septic tank 3 for no less than 30 days.

[0033] Specifically, the top of the septic tank 3 is provided with a feeding port for adding fermentation agents and spherical packing material 15, and the feeding port can be opened and closed.

[0034] Specifically, this embodiment also includes a fermentation agent periodic dispensing device 14, which is used to periodically dispense fermentation agents into the septic tank 3 through the feeding port of the septic tank 3.

[0035] Specifically, the microbial carrier placed in the anaerobic biofilm tank 8 is spherical packing material 15. The stacking volume of the spherical packing material 15 is 50%-80% of the volume of the anaerobic biofilm tank 8.

[0036] Specifically, the packing material of the non-powered wastewater purification tank 9, the packing material of the non-powered trickling filter 12, and the substrate of the modular constructed wetland 13 all include adsorption filter media, which includes at least one of nitrogen adsorption filter media 16 and phosphorus adsorption filter media 17. The nitrogen adsorption filter media 16 is used to remove nitrogen from wastewater, and the phosphorus adsorption filter media 17 is used to remove phosphorus from wastewater. In this embodiment, the adsorption filter media includes nitrogen adsorption filter media 16 and phosphorus adsorption filter media 17.

[0037] Specifically, the non-powered wastewater purification tank 9 is composed of multiple interconnected compartments, with the connecting openings between adjacent compartments staggered to avoid short-circuiting. Nitrogen adsorption filter media 16 is located in at least one compartment, and phosphorus adsorption filter media 17 is located in at least one compartment. Nitrogen adsorption filter media 16 and phosphorus adsorption filter media 17 are each in different compartments, with all nitrogen adsorption filter media 16 preceding all phosphorus adsorption filter media 17, ensuring that wastewater flows through the nitrogen adsorption filter media 16 before flowing through the phosphorus adsorption filter media 17. Nitrogen removal, especially ammonia nitrogen removal, prevents ammonia nitrogen from converting to nitrates during subsequent treatment. The presence of nitrates may adversely affect phosphorus removal efficiency; therefore, prioritizing nitrogen removal from wastewater effectively reduces the adverse effects of nitrates on phosphorus removal. In this embodiment, the non-powered wastewater purification tank 9 occupies one compartment for nitrogen adsorption filter media 16 and one for phosphorus adsorption filter media 17.

[0038] Specifically, the packing material of the non-powered wastewater purification tank 9 also includes spherical packing material 15. The spherical packing material 15 serves as an attachment carrier for microorganisms, enabling the harmless treatment of solid pollutants within the non-powered wastewater purification tank 9, further improving the wastewater treatment effect. In this embodiment, the non-powered wastewater purification tank 9 is divided into three compartments. The first compartment is filled with spherical packing material 15, the second compartment with nitrogen adsorption filter media 16, and the third compartment with phosphorus adsorption filter media 17. Each compartment of the non-powered wastewater purification tank 9 has a feeding port at its top, which can be opened and closed.

[0039] Specifically, in this embodiment, spherical packing material 15 is placed under the nitrogen adsorption filter media 16 in the second compartment of the non-powered sewage purification tank 9; spherical packing material 15 is placed under the phosphorus adsorption filter media 17 in the third compartment of the non-powered sewage purification tank 9.

[0040] Specifically, the substrate of the modular constructed wetland 13 also includes gravel. The gravel serves as an attachment carrier for microorganisms, enabling the harmless treatment of solid pollutants within the modular constructed wetland 13 and further improving wastewater treatment efficiency. Simultaneously, as a purely natural material, gravel is less likely to cause secondary pollution risks.

[0041] Specifically, the surface of the modular artificial wetland 13 is planted with plants 18, including canna lilies.

[0042] Specifically, the substrate filling area of ​​the modular constructed wetland 13 is divided into multiple interconnected cells, with the connecting openings between adjacent cells staggered to avoid short-circuiting. Nitrogen adsorption filter media 16 and phosphorus adsorption filter media 17 are each located in different cells, with all nitrogen adsorption filter media 16 preceding all phosphorus adsorption filter media 17, ensuring that wastewater flows through the nitrogen adsorption filter media 16 before flowing through the phosphorus adsorption filter media 17. Nitrogen removal, especially ammonia nitrogen removal, prevents the conversion of ammonia nitrogen to nitrates during subsequent treatment. The presence of nitrates can adversely affect phosphorus removal efficiency; therefore, prioritizing nitrogen removal from wastewater effectively reduces the adverse effects of nitrates on phosphorus removal. In this embodiment, the modular constructed wetland 13 occupies one cell for each of the nitrogen adsorption filter media 16 and phosphorus adsorption filter media 17.

[0043] Specifically, in this embodiment, the substrate filling area of ​​the modular constructed wetland 13 is divided into three compartments. The first compartment is filled with gravel, the second compartment is filled with nitrogen adsorption filter media 16, and the third compartment is filled with phosphorus adsorption filter media 17.

[0044] Specifically, the height difference between the air inlet and outlet of the non-powered trickling filter 12 exceeds 3m, and the dissolved oxygen in the wastewater is greater than 2mg / L. The height difference is not shown in the diagram; the description in the text is used for clarification. That is, the top opening of the outlet pipe 123 is more than 3m higher than the top opening of the inlet pipe 124. The inlet pipe of the non-powered trickling filter 12 extends into its center, and the effluent from the inlet pipe falls into the center of the water distributor 122, which has an opening ratio of 20%-25%. The effluent is evenly distributed into the lower adsorption filter media through small holes (18-25mm in diameter) on the water distributor 122. The non-powered trickling filter 12 contains two layers of adsorption filter media: an upper layer of nitrogen adsorption filter media 16 and a lower layer of phosphorus adsorption filter media 17.

[0045] Specifically, the nitrogen adsorption filter media 16 has a diameter of 6-8 mm and a stacking height of 300 mm or more; the phosphorus adsorption filter media 17 has a diameter of 3-5 mm and a stacking height of 600 mm or more, so that the effluent from the non-powered air-dripping filter 12 meets the water quality standards for farmland irrigation.

[0046] This embodiment also includes a regulating tank 10, which is provided with a top opening, an inlet, and an overflow outlet. The height of the overflow outlet of the regulating tank 10 is greater than or equal to the height of the inlet. The overflow outlets of all wastewater purification modules are connected to the inlet of the regulating tank 10, and the liquid overflowing from the overflow outlet of the regulating tank 10 is discharged into water bodies or farmland.

[0047] Specifically, a drip filter is installed at the overflow outlet of the regulating tank 10 to increase the contact between the liquid and air at the overflow outlet, accelerate the wastewater oxidation and decomposition process, and further improve the wastewater purification quality. The drip filter is not shown in the diagram.

[0048] This embodiment also includes a water pump 11, which is used to pump the liquid in the storage tank 10 out of the storage tank 10 through the top opening of the storage tank 10. When the water in the storage tank cannot overflow, the water pump 11 is used to pump the liquid in the storage tank 10 out of the top opening of the storage tank 10 for utilization or discharge.

[0049] Monitoring personnel can take samples from the storage tank 10 for testing. Wastewater that meets the standards can be used for irrigation and returned to the fields. Wastewater that cannot be used can be discharged to nearby water bodies through the overflow outlet of the storage tank 10 or the water pump 11.

[0050] This embodiment also includes a solar power supply device 19, which is used to supply power to the water pump 11.

[0051] Specifically, the opening area of ​​the liquid fertilizer storage tank 4 and the top opening area of ​​the regulating tank 10 are both 0.13-0.20 m2, so as to access the liquid fertilizer and water contained therein.

[0052] Specifically, the openings of the liquid fertilizer storage tank 4 and the top opening of the regulating tank 10 are both equipped with covers to ensure personnel safety while preventing weeds and fallen leaves from entering.

[0053] In summary, this embodiment treats black water, kitchen wastewater, and other grey water wastewater differently, and the entire treatment process requires no power device. The wastewater flows between the septic tank 3, liquid fertilizer storage tank 4, sedimentation oil separator 7, anaerobic biofilm tank 8, and wastewater purification module only through liquid overflow. It is easy to construct and maintain, and has low cost, making it suitable for decentralized treatment mode for rural domestic wastewater treatment.

[0054] Example 2

[0055] The design service recipient is one household with two permanent residents. Before the renovation, the household used a single-chamber septic tank (Self-Catalyst 3) with a COD of 2946.67 mg / L and a fecal coliform count of 4 × 10⁻⁴. The decentralized rural domestic sewage low-carbon differentiated treatment and resource recovery system described in Example 1 was used to treat the sewage from the design service recipient.

[0056] The toilet renovation project will use toilet 1 with a single flush volume of less than 1L for the service recipients. The water outlet of toilet 1 will be connected to a three-compartment septic tank 3 through a DN100 PVC pipe.

[0057] The three compartments of septic tank 3 are connected by pipes. The first two compartments of septic tank 3 are filled with fermentation agents and spherical packing material 15. The spherical packing material 15 occupies 50%-80% of the volume of the first compartment, and the spherical packing material 15 occupies 50%-80% of the volume of the second compartment. The third compartment of septic tank 3 serves as a storage space for harmlessly treated liquid organic fertilizer. An inspection port with a diameter of not less than 500 mm is installed in the third compartment. Liquid samples are extracted from the inspection port for testing. The COD in the liquid in the third compartment is 143.3 mg / L, and the fecal coliform count has decreased to 5.3 × 10⁻³, meeting the sanitary standards for harmless treatment of fecal waste. In this embodiment, the diameter of the inspection port is 500 mm.

[0058] Example 3

[0059] The design service target is one household with two permanent residents. The greywater flow rate is 0.20 m³ / d. The untreated greywater quality is: COD = 120 mg / L, TN = 56.10 mg / L, NH₄⁺ = 46.09 mg / L, TP = 4.99 mg / L. The decentralized rural domestic sewage low-carbon classification and resource utilization system described in Example 1 is used to treat the sewage of the design service target. In this example, the sewage purification module is only a non-powered sewage purification tank 9. The depth of the non-powered sewage purification tank 9 is 1.10 m.

[0060] Kitchen wastewater is piped into a grease trap 7, where a screen traps most of the grease and food residue. The effluent from the grease trap 7, along with other types of greywater such as laundry wastewater, flows into an anaerobic biofilm tank 8, where organic matter is initially decomposed, facilitating subsequent treatment. Testing showed that the water quality at the overflow point of the anaerobic biofilm tank 8 was COD = 53.33 mg / L, TN = 55.85 mg / L, NH4+ = 42.38 mg / L, and TP = 5.89 mg / L.

[0061] Wastewater treated in anaerobic biofilm tank 8 is then fed into a non-powered ash water purification tank for further removal of organic matter, nitrogen, and phosphorus. The non-powered ash water purification tank is divided into three interconnected compartments. The first compartment contains spherical packing material, with its volume occupying 50%-80% of the compartment's volume. The second compartment contains nitrogen adsorption filter media 16, with its volume occupying 50% of the compartment's volume. The third compartment contains phosphorus adsorption filter media 17, with its volume occupying 50% of the compartment's volume. The connecting openings between adjacent compartments are staggered to prevent short-circuiting. The water quality at the overflow outlet of the non-powered ash water purification tank is: COD = 25.67 mg / L, TN = 42.90 mg / L, NH4+ = 37.19 mg / L, TP = 4.76 mg / L, meeting the standards for agricultural irrigation water.

[0062] Wastewater treated by the non-powered greywater purification tank is fed into the regulating tank 10 for farmers to use. The portion that cannot be disposed of is discharged into nearby water bodies through the overflow outlet of the regulating tank 10.

[0063] Example 4

[0064] The design serves 3 households with a permanent population of 5. The greywater flow rate is 0.50 m³ / d. The untreated greywater quality is: COD = 53.3 mg / L, TN = 46.09 mg / L, NH₄⁺ = 19.61 mg / L, TP = 2.39 mg / L. The decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system described in Example 1 is used to treat the sewage from the designed service recipients. In this example, the sewage purification module is only a non-powered aeration trickling filter 12. The depth of the non-powered aeration trickling filter 12 is greater than 1.5 m.

[0065] Kitchen wastewater is piped into grease trap 7, where a screen trap retains most of the grease and food residue. The effluent from grease trap 7, along with other types of greywater such as laundry wastewater, flows into anaerobic biofilm tank 8 for preliminary decomposition of organic matter, facilitating subsequent treatment. Testing showed that the water quality at the overflow point of anaerobic biofilm tank 8 was COD = 13.33 mg / L, TN = 27.04 mg / L, NH4+ = 25.16 mg / L, and TP = 1.56 mg / L.

[0066] Wastewater treated in anaerobic biofilm tank 8 is then fed into a non-powered aeration trickling filter 12 for further removal of organic matter, nitrogen, and phosphorus. The height difference between the inlet and outlet of the non-powered aeration trickling filter 12 exceeds 3m, and the dissolved oxygen in the wastewater is greater than 2mg / L. The inlet pipe of the non-powered aeration trickling filter 12 extends into its center, and the effluent from the inlet pipe falls into the center of a water distributor 122 with a 20% porosity, evenly distributing through small holes (18mm in diameter) into the lower layer of adsorption filter media. The non-powered aeration trickling filter 12 contains two layers of adsorption filter media: the upper layer is nitrogen adsorption filter media 16 with a diameter of 6-8mm and a stacking height of 300mm; the lower layer is phosphorus adsorption filter media 17 with a diameter of 3-5mm and a stacking height of 600mm. The water quality at the overflow outlet of the non-powered blower filter 12 is COD=26.67mg / L, TN=15.66mg / L, NH4+=9.26mg / L, TP=1.67mg / L, which meets the standards for farmland irrigation water quality.

[0067] Wastewater treated by the non-powered air-dripping filter 12 is fed into the regulating tank 10 for farmers to use. The portion that cannot be disposed of is discharged into nearby water bodies through the overflow outlet of the regulating tank 10.

[0068] Example 5

[0069] The design service recipient is one household with two permanent residents. The greywater flow rate is 0.20 m³ / d. The untreated greywater quality is COD = 66.67 mg / L, TN = 32.97 mg / L, NH₄⁺ = 29.79 mg / L, and TP = 1.77 mg / L. The decentralized rural domestic sewage low-carbon classification and resource utilization system described in Example 1 is used to treat the sewage for the design service recipient. In this example, the sewage purification module is only the modular constructed wetland 13.

[0070] Kitchen wastewater is piped into grease trap 7, where a screen traps most of the grease and food residue. The effluent from grease trap 7, along with other types of greywater such as laundry wastewater, flows into anaerobic biofilm tank 8 for preliminary decomposition of organic matter, facilitating subsequent treatment. Testing showed that the water quality at the overflow point of anaerobic biofilm tank 8 was COD = 53.33 mg / L, TN = 47.31 mg / L, NH4+ = 25.84 mg / L, and TP = 1.33 mg / L.

[0071] Wastewater treated in anaerobic biofilm tank 8 is fed into modular constructed wetland 13. Modular constructed wetland 13 is a cuboid with dimensions of 2.03m long, 1.11m wide, and 1.10m high. The substrate filling area of ​​modular constructed wetland 13 is divided into three compartments: the first compartment is 1.02m long and filled with gravel to a height of 700mm; the second compartment is 0.34m long and filled with nitrogen adsorption filter media 16 to a height of 700mm; the third compartment is 0.67m long and filled with phosphorus adsorption filter media 17 to a height of 700mm. Canna lilies are planted on the surface of modular constructed wetland 13. The connecting openings between adjacent compartments are staggered to avoid short-circuiting. The water quality at the overflow outlet of modular constructed wetland 13 was COD = 13.33 mg / L, TN = 31.14 mg / L, NH4+ = 23.09 mg / L, and TP = 0.53 mg / L.

[0072] Wastewater treated by the modular artificial wetland 13 is fed into the regulating tank 10 for farmers to use. The portion that cannot be disposed of is discharged into nearby water bodies through the overflow outlet of the regulating tank 10.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system, characterized in that: The system includes a septic tank, a liquid fertilizer storage tank, a sedimentation and grease trap, an anaerobic biofilm tank, and a wastewater purification module. At least one wastewater purification module is provided, which can be at least one of a modular constructed wetland, a non-powered blower-drip filter, or a non-powered wastewater purification tank. Each of the septic tank, liquid fertilizer storage tank, sedimentation and grease trap, anaerobic biofilm tank, and wastewater purification module is equipped with an inlet and an overflow outlet, and the height of each overflow outlet is greater than or equal to the height of the inlet on its corresponding structure. Fermentation agents and spherical packing materials are added to the septic tank. The septic tank inlet is connected to black water, the sludge and grease trap inlet is connected to kitchen sewage, and all grey water except kitchen sewage is connected to the inlet of the anaerobic biofilm tank. The overflow outlet of the septic tank is connected to the inlet of the liquid fertilizer storage tank. The top of the liquid fertilizer storage tank is open, and the overflow outlets of the liquid fertilizer storage tank and the sludge and grease trap inlet are connected to the inlet of the anaerobic biofilm tank. The overflow outlet of the anaerobic biofilm tank is connected to the inlet of all sewage purification modules. The liquid overflowing from the overflow outlets of all sewage purification modules is discharged into water bodies or farmland. The wastewater treatment modules used in wastewater control areas are modular constructed wetlands; Set a groundwater level threshold; in non-sewage-controlled areas, the sewage purification module used in areas where the groundwater level is less than or equal to the groundwater level threshold is a non-powered air-dragging filter; in non-sewage-controlled areas, the sewage purification module used in areas where the groundwater level is greater than the groundwater level threshold is a non-powered sewage purification tank. The substrate filling area of ​​the modular constructed wetland is divided into three interconnected compartments; the first compartment is filled with gravel, the second compartment is filled with nitrogen adsorption filter media, and the third compartment is filled with phosphorus adsorption filter media. The non-powered wastewater purification tank is divided into three compartments. The first compartment is filled with spherical packing material, the second compartment is filled with nitrogen adsorption filter media, and the third compartment is filled with phosphorus adsorption filter media. Spherical packing material is placed under the nitrogen adsorption filter media in the second compartment, and spherical packing material is placed under the phosphorus adsorption filter media in the third compartment.

2. The decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 1, characterized in that: The black water comes from toilets with a single flush volume of less than 1L; the dosage of fermentation agent is 300-500mL / m³. 3 The volume of the spherical packing material is 50%-80% of the fermentation space volume of the septic tank.

3. The decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 2, characterized in that: The black water must remain in the septic tank for no less than 30 days.

4. The decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 1, characterized in that: The microbial carrier placed in the anaerobic biofilm tank is a spherical packing material; the stacking volume of the spherical packing material is 50%-80% of the volume of the anaerobic biofilm tank.

5. The decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 1, characterized in that: The packing material of the non-powered wastewater purification tank, the packing material of the non-powered blower-drip filter, and the substrate of the modular constructed wetland all include adsorption filter media, which includes at least one of nitrogen adsorption filter media and phosphorus adsorption filter media.

6. A decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 5, characterized in that: The packing material for the non-powered wastewater purification tank also includes spherical packing material.

7. A decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 5, characterized in that: The substrate of the modular constructed wetland also includes gravel.

8. A decentralized rural domestic sewage low-carbon differentiated treatment and resource recovery system according to any one of claims 1-7, characterized in that: It also includes a regulating tank, which is equipped with a top opening, an inlet and an overflow outlet. The height of the overflow outlet of the regulating tank is greater than or equal to the height of the inlet of the regulating tank. The overflow outlets of all sewage purification modules are connected to the inlet of the regulating tank, and the liquid overflowing from the overflow outlet of the regulating tank is discharged into water bodies or farmland.

9. A decentralized rural domestic sewage low-carbon differentiated treatment and resource utilization system according to claim 8, characterized in that: It also includes a water pump, which is used to pump the liquid in the storage tank out of the storage tank from the top opening when the water in the storage tank cannot overflow and be discharged, for use or discharge.

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