Distributed rural sewage septic tank and purification tank coupling treatment system

Abstract

The invention discloses a distributed rural sewage septic tank and purification tank coupling treatment system which is characterized in that a feed port of an improved septic tank is connected with a flushing toilet, and a discharge port of the improved septic tank is connected with a feed port of an electrochemical enhanced purification tank; a discharge port of the electrochemical enhanced purification tank is further connected with a kitchen and a bath room, the improved septic tank is connected with the fertilization pipeline system, the electrochemical enhanced purification tank is connected with the watering pipeline system, and ultraviolet disinfection equipment and a three-dimensional electrochemical treatment structure are arranged in the electrochemical enhanced purification tank; the chemical oxygen demand and the biochemical oxygen demand of black water are effectively reduced after the black water is cured in the septic tank for enough time, the black water is mixed with grey water to enter the electrochemical enhanced purification tank and then treated by a biological and electrochemical combined method, and the sewage is disinfected by an electrochemical and ultraviolet disinfection combined mode, so that the effluent reaches the reuse standard.

Description

Technical Field

[0001] The present invention relates to the field of rural domestic sewage treatment and resource utilization, and in particular to a decentralized rural sewage septic tank and septic tank coupled treatment system. Background Art

[0002] In order to improve the rural environment and realize the resource utilization of sewage, it is necessary to treat the sewage generated in rural life.

[0003] However, decentralized rural sewage treatment is not feasible due to issues such as dispersed and volatile discharge, insufficient funding, and low technical management. Rural areas lack adequate pipe networks and infrastructure, making it difficult to replicate urban sewage treatment technologies and processes. Therefore, a sewage treatment system suitable for decentralized rural domestic sewage treatment is urgently needed. Furthermore, due to the significant fluctuations in both quality and quantity of rural sewage, existing technologies often fail to meet water quality standards, necessitating the addition of additional dephosphorization agents and disinfectants. Summary of the Invention

[0004] The purpose of the present invention is to provide a decentralized rural sewage septic tank and septic tank coupling treatment system, which prolongs the treatment time of the traditional three-chamber septic tank, innovatively introduces three-dimensional electrochemical denitrification and phosphorus removal technology into the septic tank, and combines it with ultraviolet disinfection. No chemical agents are required in the entire treatment process. It has the advantages of high sewage treatment efficiency, simple operation and maintenance management, and low energy consumption. It can effectively solve the problems encountered in the field of domestic sewage treatment technology at this stage. In addition, black and ash separation is implemented on the incoming water, and resource utilization is carried out differently, turning waste into treasure, and realizing the utilization of rural sewage resources.

[0005] The above-mentioned optimized structure of the present invention is achieved through the following technical solutions: a decentralized rural sewage septic tank and septic tank coupled treatment system, including ultraviolet disinfection equipment, solar power supply equipment, toilet flushing, kitchen, bathroom, fertilizer pipeline system, watering pipeline system, improved septic tank, electrochemical enhanced septic tank, and three-dimensional electrochemical treatment structure; The feed port of the improved septic tank is connected to the flushing toilet, and the discharge port of the improved septic tank is connected to the feed port of the electrochemically enhanced purification tank; the discharge port of the electrochemically enhanced purification tank is also connected to the kitchen and the bathroom, the improved septic tank is connected to the fertilization pipeline system, the electrochemically enhanced purification tank is connected to the watering pipeline system, the electrochemically enhanced purification tank is provided with the ultraviolet disinfection equipment and the three-dimensional electrochemical treatment structure, and the solar power supply equipment is electrically connected to the ultraviolet disinfection equipment, the fertilization pipeline system, the watering pipeline system, the electrochemically enhanced purification tank, and the three-dimensional electrochemical treatment structure.

[0006] Preferably, the improved septic tank includes a first septic compartment, a second septic compartment, and a third septic compartment connected in sequence, the first septic compartment is connected to the flushing toilet, and the third septic compartment is connected to the fertilizer pipeline system and the feed port of the electrochemically enhanced purification tank; the first septic compartment, the second septic compartment, and the third septic compartment are all provided with folding plates.

[0007] Preferably, the electrochemical enhanced purification tank comprises a regulating tank, an anaerobic tank, an anoxic tank, an aerobic tank and a sedimentation tank connected in sequence, the sedimentation tank is connected to the watering pipeline system, and the ultraviolet disinfection equipment is provided in the sedimentation tank; The regulating tank is connected to the improved septic tank, the kitchen, and the bathroom; The aerobic tank is provided with the three-dimensional electrochemical treatment structure and an air pump; the anaerobic tank and the anoxic tank are both provided with MBBR fillers.

[0008] Preferably, the three-dimensional electrochemical treatment structure includes an anode tube, a cathode mesh is provided in the anode tube, a stainless steel screen is provided between the anode tube and the cathode mesh, and a three-dimensional granular electrode filler is provided between the anode tube and the stainless steel screen.

[0009] Preferably, the anode tube is an aluminum alloy tube, the cathode mesh is a titanium mesh, the three-dimensional particle electrode filler is sponge iron, and the three-dimensional electrochemical treatment structure uses microcurrent.

[0010] Preferably, the three-dimensional granular electrode filler is biochar doped with magnesite.

[0011] Preferably, the fertilization pipeline system includes a first lifting pump and an annular perforated fertilization pipeline, and the first lifting pump is arranged between the improved septic tank and the annular perforated fertilization pipeline.

[0012] Preferably, the annular perforated fertilizing pipeline has small holes with a diameter of 20 mm opened every 0.5 meters to facilitate uniform fertilization.

[0013] Preferably, the watering pipeline system includes a second lifting pump, an annular watering pipeline, and an atomizing water spraying device. The second lifting pump is provided between the electrochemically enhanced purification tank and the annular watering pipeline, and a plurality of the atomizing water spraying devices are provided on the annular watering pipeline.

[0014] Preferably, a plurality of the atomizing water spraying devices are arranged at intervals of 1 meter in the annular watering pipeline to facilitate uniform watering.

[0015] One or more of the above technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: 1) The present invention adopts a three-stage gradient sedimentation method for the improved septic tank and arranges a folded plate at 1 / 3 of each stage to change the internal flow state of the improved septic tank from horizontal flow to a more efficient folded flow, thereby optimizing the sedimentation performance and anaerobic digestion, achieving efficient retention of suspended solids (SS) (removal rate ≥ 75%) and initial degradation of organic matter (COD) (removal rate 30-40%), and effectively alleviating the load pressure of subsequent treatment units.

[0016] 2) A three-dimensional electrochemical treatment structure is added to the traditional septic tank aerobic pool. Each partition and electrode sheet is detachable and reusable, which improves the equipment's ability to withstand shock loads. Direct anode oxidation under microcurrent, electrocoagulation and microbial simultaneous nitrification and denitrification work synergistically to achieve synergistic removal of carbon, nitrogen and phosphorus for dissolved pollutants (NH3-N, TN, TP). The oxidation efficiency of ammonia nitrogen is 2.3-3.1 times higher than that of traditional biological methods, and the TP removal rate is stably above 92%, eliminating the need for external dephosphorization agents and disinfectants. The overall operating energy consumption of the equipment is low, and the life of the electrode material is extended to more than 5 years, making maintenance and management easy.

[0017] 3) After the black water has been matured for a sufficient time in the improved septic tank, it can be used for farmland fertilization. The effluent from the improved septic tank and the gray water are mixed and entered into the electrochemically enhanced purification tank for treatment through a combination of biological and electrochemical methods. This method does not require the addition of external agents and is convenient for operation and maintenance management. The sewage is disinfected by combining electrochemistry with ultraviolet disinfection, which can enhance the denitrification and phosphorus removal and sterilization and disinfection capabilities of the purification tank, so that the effluent meets the Level A standard of the "Jiangxi Rural Domestic Sewage Discharge Standard" (DB36 / 1102-2019) and my country's "Farmland Irrigation Water Quality Standard" (GB 5084-2021), and can be used for farmland watering. All the above electrical equipment are powered by solar energy, which can achieve zero operation and maintenance costs while treating rural sewage and utilizing it as a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of the structural distribution of the present invention; Figure 2 It is a plan view of the sewage treatment system of the present invention; Figure 3 is a planar schematic diagram of the three-dimensional electrochemical treatment structure of the present invention; Figure 4It is a cross-sectional schematic diagram of the three-dimensional electrochemical treatment structure of the present invention.

[0020] Among them: 1. First septic tank; 2. Second septic tank; 3. Third septic tank; 4. Folding plate; 5. First lifting pump; 6. Equalization tank; 7. Anaerobic tank; 8. Anoxic tank; 9. Aerobic tank; 10. Sedimentation tank; 11. MBBR filler; 12. Anode tube; 13. Cathode mesh; 14. Three-dimensional granular electrode filler; 15. Stainless steel screen; 16. UV disinfection equipment; 17. Solar power supply equipment; 18. Flushing toilet; 19. Kitchen; 20. Bathroom; 21. Fertilization pipeline system; 22. Watering pipeline system; 23. Air pump; 24. Improved septic tank; 25. Electrochemically enhanced purification tank; 26. Three-dimensional electrochemical treatment structure; 27. Second lifting pump; 28. Annular perforated fertilization pipeline; 29. ​​Annular watering pipeline; 30. Atomizing water spraying device. DETAILED DESCRIPTION

[0021] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0022] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0024] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0025] Example 1 Reference Attachment Figure 1-4 A decentralized rural sewage septic tank and septic tank coupling treatment system includes ultraviolet disinfection equipment 16, solar power supply equipment 17, toilet 18, kitchen 19, bathroom 20, fertilizer pipeline system 21, watering pipeline system 22, improved septic tank 24, electrochemical enhanced septic tank 25, three-dimensional electrochemical treatment structure 26; the feed port of the improved septic tank 24 is connected to the toilet 18, the improved septic tank 24 can ensure that the black water is fully matured, the improved septic tank 24 is connected to the fertilizer pipeline system 21, and the fully matured black water enters The water enters the fertilizer pipeline system 21 to achieve fertilization of the farmland. The feed port of the electrochemically enhanced purification tank 25 is connected to the discharge port of the improved septic tank 24, the kitchen 19, and the bathroom 20. The black water and gray water flowing out of the improved septic tank 24 are sufficient to form a mixed black and gray sewage, which enters the electrochemically enhanced purification tank 25 for deep treatment. The electrochemically enhanced purification tank 25 is connected to the watering pipeline system 22. The sewage after deep treatment in the electrochemically enhanced purification tank 25 meets the discharge standards or enters the watering pipeline system 22 to achieve water utilization. The electrochemically enhanced purification tank 25 is equipped with ultraviolet disinfection equipment 16 and a three-dimensional electrochemical treatment structure 26. The three-dimensional electrochemical treatment structure 26 can not only effectively enhance the system's denitrification and phosphorus removal capabilities, but also use electrochemistry for sterilization and disinfection. It is used in conjunction with the ultraviolet disinfection equipment 16 in the electrochemically enhanced purification tank 25 to ensure that the effluent of the electrochemically enhanced purification tank 25 meets the reuse standards, thereby achieving water resource utilization.

[0026] The solar power supply device 17 is electrically connected to the ultraviolet disinfection equipment 16, the fertilization pipeline system 21, the watering pipeline system 22, the electrochemically enhanced purification tank 25, and the three-dimensional electrochemical treatment structure 26. The solar power supply device 17 converts solar energy into electrical energy to achieve the normal operation of the ultraviolet disinfection equipment 16, the fertilization pipeline system 21, the watering pipeline system 22, the electrochemically enhanced purification tank 25, and the three-dimensional electrochemical treatment structure 26, thereby saving energy.

[0027] Preferably, the improved septic tank 24 includes a first septic compartment 1, a second septic compartment 2, and a third septic compartment 3 connected in sequence. The first septic compartment 1 is connected to the flush toilet 18 (the wastewater flowing out of the flush toilet 18 is black water), and the third septic compartment 3 is connected to the fertilizer pipeline system 21 and the feed port of the electrochemical enhanced purification tank 25. The first septic compartment 1, the second septic compartment 2, and the third septic compartment 3 can extend the retention time of black water in the improved septic tank 24 to ensure full maturation of the black water. Both the septic tank 2 and the third septic tank 3 are provided with a folded plate 4, which can be arranged at 1 / 3 of each septic tank. The folded plate 4 can change the internal flow state of black water in the improved septic tank 24 from horizontal flow to more efficient baffled flow, thereby optimizing the sedimentation performance and anaerobic digestion of black water in the improved septic tank 24, achieving efficient retention of suspended solids (SS) (removal rate ≥ 75%) and preliminary degradation of organic matter (COD) (removal rate 30-40%), and effectively alleviating the load pressure of subsequent treatment units.

[0028] Preferably, the electrochemically enhanced purification tank 25 includes a regulating tank 6, an anaerobic tank 7, an anoxic tank 8, an aerobic tank 9 and a sedimentation tank 10 connected in sequence. The regulating tank 6 is connected to the improved septic tank 24, the kitchen 19, and the bathroom 20 (the wastewater flowing out of the kitchen 19 and the bathroom 20 is gray water). The black water and gray water flowing out of the improved septic tank 24 can be fully mixed, so that the flow rate and water quality of the black and gray mixed sewage are uniform, which is convenient for subsequent deep treatment. The aerobic tank 9 is provided with a three-dimensional electrochemical treatment structure 26 and an air pump 23; the three-dimensional electrochemical treatment structure 26 can not only effectively enhance the decontamination of the system, but also effectively improve the decontamination of the system. Nitrogen and phosphorus removal capabilities can also be enhanced by electrolysis to produce active substances such as chloride ions and oxygen for sterilization and disinfection. Sedimentation tank 10 is connected to watering system 22 and is equipped with ultraviolet disinfection equipment 16 to sterilize the water within. UV disinfection equipment 16 can be secured with a removable fixing ring for easy regular maintenance and cleaning. UV disinfection equipment 16 can utilize a UV lamp and be combined with a three-dimensional electrochemical treatment structure 26. When UV disinfection equipment 16 is irradiated into water treated with chloride ions, the UV light synergizes with the chloride ions, accelerating the inactivation of E. coli. This combined action improves the efficiency of E. coli removal, ensures water quality, and ensures that the effluent from electrochemically enhanced purification tank 25 meets reuse standards. At the same time, the chloride ions generated during the treatment process of the three-dimensional electrochemical treatment structure 26 can be removed by the ultraviolet disinfection equipment 16, avoiding the secondary pollution caused by traditional chlorine disinfection. The air pump 23 can realize the aeration of the aerobic tank 9. The anaerobic tank 7 and the anoxic tank 8 are both equipped with MBBR fillers 11 (moving bed biofilm reactor fillers), which can improve the removal effect of the anaerobic tank 7 and the anoxic tank 8 on pollutants.

[0029] Preferably, the three-dimensional electrochemical treatment structure 26 includes an anode tube 12 , a cathode mesh 13 is provided inside the anode tube 12 , a stainless steel screen 15 is provided between the anode tube 12 and the cathode mesh 13 , and a three-dimensional granular electrode filler 14 is provided between the anode tube 12 and the stainless steel screen 15 .

[0030] Under the action of microcurrent, the anode tube 12 is directly oxidized, and the electro-flocculation and microbial synchronous nitrification and denitrification work synergistically to achieve the synergistic removal of carbon, nitrogen and phosphorus for dissolved pollutants (NH3-N, TN, TP). The oxidation efficiency of ammonia nitrogen is increased by 2.3-3.1 times compared with traditional biological methods, and the TP removal rate is stably above 92%.

[0031] Preferably, the anode tube 12 is made of aluminum alloy tube, the cathode mesh 13 is made of titanium mesh, and the three-dimensional granular electrode filler 14 is made of sponge iron to improve the pollutant removal efficiency and reduce the energy consumption of the electrochemical system. The three-dimensional electrochemical treatment structure 26 can use microcurrent to achieve low-energy operation, which reduces energy consumption by 37% compared with traditional electrochemical processes, and extends the life of the electrode material to more than 5 years.

[0032] Preferably, the fertilizer pipeline system 21 includes a first lifting pump 5 and an annular perforated fertilizer pipeline 28. The first lifting pump 5 is arranged between the third septic tank 3 and the annular perforated fertilizer pipeline 28. The black water in the third septic tank 3 can be introduced into the annular perforated fertilizer pipeline 28 through the first lifting pump 5 to achieve fertilization of the farmland. The first lifting pump 5 can be a lifting pump with an interception system to prevent solid impurities from entering the first lifting pump 5 and causing damage to the pump body.

[0033] Preferably, the annular perforated fertilizing pipeline 28 can be arranged in a ring shape according to the location of the farmland, and a small hole with a diameter of 20 mm can be opened every 0.5 meters to facilitate uniform fertilization.

[0034] Preferably, the watering pipeline system 22 includes a second lifting pump 27, an annular watering pipeline 29, and an atomizing water spraying device 30. A second lifting pump 27 is provided between the sedimentation tank 10 and the annular watering pipeline 29. The water from the sedimentation tank 10 can be introduced into the annular watering pipeline 29 through the second lifting pump 27. The second lifting pump 27 can be a lifting pump with an interception system to prevent solid impurities from entering the second lifting pump 27 and causing damage to the pump body. A plurality of atomizing water spraying devices 30 are provided on the annular watering pipeline 29. The atomizing water spraying devices 30 can evenly spray the water in the annular watering pipeline 29 to the farmland to realize the recycling of water resources.

[0035] Preferably, the annular watering pipeline 29 can be arranged according to the actual situation of the farmland, and multiple atomizing water spraying devices 30 are set at intervals of 1 meter in the annular watering pipeline 29 to facilitate uniform watering and meet the water demand of the farmland.

[0036] Preferably, the fertilizer piping system 21 and the watering piping system 22 are started when there is a demand for fertilizer or watering, and the water from the improved septic tank 24 is used for fertilizer, and the water from the electrochemically enhanced purification tank 25 is used for watering. When there is no demand, the water from the improved septic tank 24 enters the electrochemically enhanced purification tank 25 for further treatment, and the water from the electrochemically enhanced purification tank 25 meets the discharge standards.

[0037] The specific working principle is as follows: During specific use, the black water flowing out of the toilet 18 enters the first septic tank 1, and passes through the second septic tank 2 and the third septic tank 3 successively. After passing through multiple septic tanks, the retention time of the black water can be extended, thereby ensuring that the black water is fully matured. When there is a need for fertilization, the black water in the third septic tank 3 can enter the fertilizer pipeline system 21 through the first lifting pump 5 for farmland fertilization. The annular perforated fertilizer pipeline 28 is arranged according to the location of the farmland, and the pipeline is evenly perforated to meet the fertilization needs.

[0038] During daily operation, the black water flowing out of the third septic tank 3 is mixed with the gray water flowing out through the kitchen 19 and the bathroom 20, and the black and gray mixed sewage enters the electrochemical enhanced purification tank 25 for deep treatment. The treated sewage meets the discharge standards or enters the watering pipe system 22 through the second lifting pump 27 in the sedimentation tank 10.

[0039] After the black-ash mixed sewage is settled in the regulating tank 6, the flow rate and water quality of the black-ash mixed sewage are uniformed, which is convenient for subsequent deep treatment. The black-ash mixed sewage then enters the anaerobic tank 7. In the anoxic environment, microorganisms decompose the organic matter in the black-ash mixed sewage and reduce the concentration of pollutants; then it enters the anoxic tank 8 to further remove nitrogen and other pollutants; the MBBR filler 11 in the anaerobic tank 7 and the anoxic tank 8 can improve the pollutant removal effect in the black-ash mixed sewage. Next, the sewage enters the aerobic tank 9, which is aerated by the air pump 23, and uses oxygen and aerobic microorganisms to further decompose organic matter, and denitrifies and removes phosphorus from the black-ash mixed sewage through the three-dimensional electrochemical treatment structure 26. Activated sludge adheres to the surface of the sponge iron filler to form The biofilm strengthens the removal of nitrogen and phosphorus, and enhances the removal effect of pollutants such as chemical oxygen demand (COD), total phosphorus and ammonia nitrogen. At the same time, the active free radicals generated by the electric field and electrochemical reaction have a certain inactivation effect on pathogenic microorganisms, thereby achieving the sterilization and disinfection of black and gray sewage. The sewage is then sterilized and disinfected by the ultraviolet disinfection equipment 16 in the sedimentation tank 10 to meet the discharge standards. The treated sewage is discharged, and the solid matter in the black and gray mixed sewage is precipitated here to form sludge. When there is a need for watering, it enters the watering pipeline system 22 for farmland watering through the second lifting pump 27 in the sedimentation tank 10. The annular watering pipeline 29 can be arranged according to the location of the farmland, and the annular watering pipeline 29 is evenly provided with an atomizing water spraying device 30 to meet the water demand of the farmland.

[0040] All of the above power equipment is powered by solar energy. The entire system does not require any external chemicals, is simple to maintain and manage, and can achieve zero operating costs.

[0041] Example 2 In order to further improve the phosphorus removal effect of sewage, the position of the three-dimensional electrode filler is changed so that the three-dimensional electrode filler is closer to the cathode plate. In this embodiment, the total phosphorus removal effect is improved to a certain extent, and the total nitrogen and ammonia nitrogen removal effects are slightly reduced.

[0042] Example 3 This embodiment differs from embodiment 1 in that: The three-dimensional granular electrode filler 14 uses biochar doped with magnesite. Agricultural waste (straw, corn cobs) can be used, after first undergoing de-stoning, crushing, and screening. Before preparing the biochar granular electrode, the granular powder is washed multiple times with deionized water and alcohol, then dried at 60°C for at least 24 hours. Agricultural waste, magnesite, water glass, and water are mixed in a certain proportion and placed in a mold. The mixture is then dried at 120°C for 18 hours. The dried material is then calcined at 700°C for 120 minutes in a tube furnace under a nitrogen atmosphere. The resulting material is then washed multiple times with deionized water to produce the biochar filler. The entire process utilizes natural raw materials and waste, making it low-cost and sustainable. It also eliminates the need for complex chemical reagents, reducing the risk of secondary pollution. The removed phosphorus can be recycled as a slow-release fertilizer (such as struvite), achieving resource utilization of pollutants.

[0043] Magnesite is mixed with biomass in a specific ratio and co-pyrolyzed at 500-800°C. During the pyrolysis process, the biomass is converted into biochar with a high specific surface area and rich pore structure, while the magnesite is decomposed into active substances such as MgO or Mg(OH)2. The two form a composite electrode material that enhances redox activity and promotes rapid electrochemical reactions.

[0044] The prepared magnesite-doped biochar particles are used as three-dimensional particle electrode fillers 14 and filled into the three-dimensional electrochemical treatment structure 26. The magnesite-doped biochar particles form an electrode layer with a three-dimensional porous structure, creating an environment for sufficient contact between pollutants and electrode materials.

[0045] The electrochemical reaction device is started under the action of microcurrent, and the wastewater to be treated is introduced into the system. A direct oxidation reaction occurs in the anode tube 12, and at the same time, the magnesite biochar composite material in the electrode filler 14 plays a role: the conductive network of biochar provides an electron transmission channel for the electrochemical reaction, and the Mg-based compound and the surface functional groups of biochar synergistically promote the adsorption and redox reaction of dissolved pollutants (NH3N, TN, TP). In the phosphorus removal process, Mg 2+ Released from the electrode material and PO4 3-Combined with the formation of Mg3(PO4)2 and other precipitation, chemical enhanced phosphorus removal is achieved; in the denitrification process, NO3 - and NH4 + Redox reactions such as electrocatalytic denitrification occur on the electrode surface. The treated wastewater flows out of the system, completing the purification process.

[0046] Oxygen-containing functional groups (such as carboxyl and hydroxyl groups) on the biochar surface can bind to the basic sites of Mg-based compounds, forming a synergistic adsorption-catalytic interface, enhancing the adsorption and redox efficiency of nitrogen and phosphorus pollutants. The porous structure of biochar binds to the alkaline surface of MgO through electrostatic adsorption, further enhancing phosphorus enrichment (especially under acidic conditions). The micro-mesoporous structure of biochar, combined with the nanoparticles of Mg-based compounds, provides an efficient physical adsorption pathway for dissolved nitrogen. The high-specific-surface-area porous structure (up to 300–800 m² / g) formed by co-pyrolysis increases the contact area with pollutants and shortens the reaction mass transfer distance. The biochar acts as a framework to support the magnesite derivative, reducing the loss of active components (e.g., achieving 80% Mg utilization), thereby extending the life of the electrode.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A decentralized rural sewage septic tank and septic tank coupled treatment system, characterized in that: Including ultraviolet disinfection equipment (16), solar power supply equipment (17), toilet flushing (18), kitchen (19), bathroom (20), fertilizer pipeline system (21), watering pipeline system (22), improved septic tank (24), electrochemical enhanced purification tank (25), three-dimensional electrochemical treatment structure (26); The feed port of the improved septic tank (24) is connected to the flushing toilet (18), and the discharge port of the improved septic tank (24) is connected to the feed port of the electrochemically enhanced purification tank (25); the discharge port of the electrochemically enhanced purification tank (25) is also connected to the kitchen (19) and the bathroom (20), the improved septic tank (24) is connected to the fertilization pipeline system (21), the electrochemically enhanced purification tank (25) is connected to the watering pipeline system (22), the ultraviolet disinfection equipment (16) and the three-dimensional electrochemical treatment structure (26) are provided in the electrochemically enhanced purification tank (25), and the solar power supply equipment (17) is electrically connected to the ultraviolet disinfection equipment (16), the fertilization pipeline system (21), the watering pipeline system (22), the electrochemically enhanced purification tank (25), and the three-dimensional electrochemical treatment structure (26).

2. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 1, characterized in that: The improved septic tank (24) comprises a first septic compartment (1), a second septic compartment (2), and a third septic compartment (3) connected in sequence, wherein the first septic compartment (1) is connected to the flush toilet (18), and the third septic compartment (3) is connected to the fertilizer pipeline system (21) and the feed port of the electrochemical enhanced purification tank (25); and folding plates (4) are provided in the first septic compartment (1), the second septic compartment (2), and the third septic compartment (3).

3. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 1, characterized in that: The electrochemically enhanced purification tank (25) comprises a regulating tank (6), an anaerobic tank (7), an anoxic tank (8), an aerobic tank (9) and a sedimentation tank (10) connected in sequence, the sedimentation tank (10) being connected to the watering pipe system (22), and the ultraviolet disinfection equipment (16) being provided in the sedimentation tank (10); The regulating tank (6) is connected to the improved septic tank (24), the kitchen (19), and the bathroom (20); The aerobic tank (9) is provided with the three-dimensional electrochemical treatment structure (26) and the air pump (23); the anaerobic tank (7) and the anoxic tank (8) are both provided with MBBR fillers (11).

4. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 3, characterized in that: The three-dimensional electrochemical treatment structure (26) comprises an anode tube (12), a cathode mesh (13) is provided in the anode tube (12), a stainless steel screen (15) is provided between the anode tube (12) and the cathode mesh (13), and a three-dimensional granular electrode filler (14) is provided between the anode tube (12) and the stainless steel screen (15).

5. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 4, characterized in that: The anode tube (12) is made of an aluminum alloy tube, the cathode mesh (13) is made of a titanium mesh, the three-dimensional particle electrode filler (14) is made of sponge iron, and the three-dimensional electrochemical treatment structure (26) uses microcurrent.

6. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 4, characterized in that: The three-dimensional particle electrode filler (14) is biochar doped with magnesite.

7. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 1, characterized in that: The fertilization pipeline system (21) comprises a first lifting pump (5) and an annular perforated fertilization pipeline (28), wherein the first lifting pump (5) is arranged between the improved septic tank (24) and the annular perforated fertilization pipeline (28).

8. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 7, characterized in that: The annular perforated fertilizing pipeline (28) has small holes with a diameter of 20 mm opened every 0.5 meters to facilitate uniform fertilization.

9. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 1, characterized in that: The watering pipeline system (22) includes a second lifting pump (27), an annular watering pipeline (29), and an atomizing water spraying device (30). The second lifting pump (27) is provided between the electrochemically enhanced purification tank (25) and the annular watering pipeline (29), and a plurality of the atomizing water spraying devices (30) are provided on the annular watering pipeline (29).

10. The decentralized rural sewage septic tank and septic tank coupled treatment system according to claim 9, characterized in that: A plurality of the atomizing water spraying devices (30) are arranged at intervals of 1 meter on the annular watering pipeline (29) to facilitate uniform watering.

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