Integrated device for low-carbon treatment of rural sewage

Abstract

The application relates to the technical field of sewage treatment, in particular to an integrated device for low-carbon treatment of rural sewage, which comprises a main reactor, a water inlet and distribution system, a biochar gradient filter material layer, a tidal flow inundation area, a water outlet collection system and a sludge mineralization area. The inside of the main reactor is divided into the sludge mineralization area, the biochar gradient filter reaction area, the tidal flow inundation area and the super-high protection area from bottom to top. The automatic periodic drainage and reoxygenation are realized by using the self-siphon principle of the simulated tidal flow, and any power equipment is not needed; the dissolved oxygen gradient distribution is constructed through the biochar gradient filter material layer, the organic combination of the aerobic, anoxic and anaerobic environments is realized in the same reactor, the whole-process treatment of organic matter degradation, denitrification and phosphorus removal is completed, the treatment effect is stable, the land occupation area is small, the cost is saved, the device is low-carbon and environment-friendly, and the water quality of the outlet water is stable and reaches the first-level B standard in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an integrated device for low-carbon treatment of rural wastewater, suitable for low-carbon and energy-saving treatment of decentralized domestic wastewater in rural areas, and especially suitable for remote rural areas lacking professional operation and maintenance personnel. Background Technology

[0002] Rural domestic sewage mainly includes kitchen sewage, washing sewage, bathing sewage, and toilet flushing sewage, and is characterized by small water volume, large fluctuations in water quality, dispersed discharge, and difficulty in collection.

[0003] Existing rural wastewater treatment technologies mainly fall into the following categories: (1) Activated sludge process and its improved processes, such as AAO process, SBR process, AO process, etc. These processes have good treatment effects, but they have high energy consumption, high operating costs, and require professional operation and maintenance personnel, and are not suitable for rural areas. (2) Biofilm methods, such as biofilters, biological contact oxidation tanks, MBBR processes, etc., although improved compared to activated sludge methods, still require power equipment such as blowers for aeration and water pumps for lifting, and the operating costs are still relatively high. (3) Although artificial wetland treatment systems have low operating costs, they occupy a large area, their treatment effect is significantly affected by the seasons, and they are prone to clogging, making them difficult to promote in rural areas where land resources are scarce. (4) Integrated wastewater treatment equipment, such as containerized AAO devices and septic tanks, although highly integrated, still rely on mechanical aeration and power equipment, resulting in high complexity of operation and maintenance.

[0004] In summary, existing rural wastewater treatment technologies share the following common technical bottlenecks: First, the treatment processes are highly dependent on power equipment, leading to high operating costs; second, integrated equipment is complex to operate and maintain, making it unsuitable for rural areas lacking skilled technicians; third, most processes cannot achieve true zero carbon emissions and zero sludge discharge; fourth, there is an irreconcilable contradiction between treatment effectiveness and operating costs—low-cost solutions often have unstable treatment results, while high-efficiency solutions have high investment and operating costs. Therefore, developing a truly low-carbon, energy-saving, easy-to-operate, and stable integrated rural wastewater treatment device is of significant practical importance and application value. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated device for low-carbon treatment of rural sewage, so as to solve the problems mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an integrated device for low-carbon treatment of rural sewage, comprising a main reactor, an inlet water distribution system, a simulated tidal flow self-siphoning system, a biochar gradient filter media layer, and an effluent collection system. The main reactor is internally divided into a reaction zone and a collection tank by a partition. The reaction zone consists of, from bottom to top, a sludge mineralization zone, a biochar gradient filtration reaction zone, a tidal flow submerged zone, and an ultra-high temperature protection zone. The collection tank is equipped with an outlet pipe to form the effluent collection system. The tidal flow flooded area is equipped with a simulated tidal flow self-siphoning system. The simulated tidal flow self-siphoning system includes a siphon pipe placed inside the main reactor. The upper end of the siphon pipe is equipped with a siphon triggering cavity. The siphon triggering cavity is equipped with a magnetic triggering mechanism. The outside of the siphon triggering cavity is connected to a siphon outlet pipe in the water collection tank. The biochar gradient filter media layer is located in the middle of the main reactor. From bottom to top, it consists of a bottom layer of honeycomb activated carbon, a middle layer of honeycomb activated carbon, and an upper layer of honeycomb activated carbon. Each layer is separated by a stainless steel wire mesh fixing layer. The upper end of the biochar gradient filter media layer is provided with a stainless steel wire mesh and a polypropylene geotextile separating layer, and the bottom is provided with a stainless steel wire mesh fixing separating layer.

[0007] Preferably, the water inlet and distribution system includes an inlet pipe located at the bottom of the biochar gradient filtration reaction zone, the inlet pipe being connected to a water distributor, and the water distributor being an annular perforated pipe or a radial water distribution structure. The water collection system includes a water collection tank and a water outlet pipe.

[0008] Preferably, a one-way breathing valve is provided at the top of the main reactor, the one-way breathing valve is connected to a ventilation pipe, and the other end of the ventilation pipe extends to the outside of the main reactor.

[0009] Preferably, the siphon triggering chamber is a sealed cavity with a magnetic triggering mechanism inside. The magnetic triggering mechanism includes a permanent magnet fixing base, and a magnetic sealing cover is provided above the permanent magnet fixing base. The magnetic sealing cover has a built-in permanent magnet, and the magnetic sealing cover is fixedly connected to the permanent magnet fixing base by a fastener. When the liquid level in the tidal flow flooded area rises to the designed high water level, the gas in the siphon inlet pipe is compressed, triggering the magnetic triggering mechanism, which creates a negative pressure in the siphon pipe to start the siphon effect, and the sewage in the tidal flow flooded area is discharged.

[0010] Preferably, the main reactor is a vertical cylindrical or cuboid structure made of fiberglass.

[0011] Preferably, the sludge mineralization zone is located at the bottom of the main reactor, and a connecting pipe is provided inside the sludge mineralization zone to connect with the sludge discharge zone. The sludge mineralization zone is connected to the bottom of the independent sludge discharge zone inside the main reactor to discharge sludge from the system.

[0012] Preferably, the activated carbon used in the bottom layer, middle layer, and top layer of the honeycomb activated carbon is made by pyrolyzing rice husks at 400°C with limited oxygen for 3 hours, followed by modification treatment with 20% nitric acid at 60°C for 2 hours, and washing until neutral before use. The biochar has a pH value of 7.2-7.8 and a specific surface area of ​​not less than 350 m². 2 / g.

[0013] Preferably, the honeycomb activated carbon bottom layer has a thickness of 300 mm and a pore size of 8 mm; The thickness of the honeycomb activated carbon intermediate layer is 400 mm, and the pore size is 4 mm; The upper layer of the honeycomb activated carbon is 300mm thick and has a pore size of 1.5mm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes the principle of tidal flow self-siphoning to achieve automatic periodic drainage and reoxygenation. The entire process requires no power equipment or electrical control system, such as pumps, fans, or valves, resulting in zero energy consumption. It is suitable for rural areas lacking or with unstable power supply, enabling zero-power operation. Because the device has no moving parts, it requires no professional technicians for maintenance; only periodic (quarterly) cleaning and inspection of the siphon control system is needed. The workload for operation and maintenance is extremely low, solving the problem of rural sewage treatment facilities being affordable to build but unaffordable to operate.

[0015] By constructing a dissolved oxygen gradient distribution through a biochar gradient filter layer, an organic combination of aerobic, anoxic, and anaerobic environments was achieved within the same reactor. This enabled the completion of the entire process of organic matter degradation, nitrification-denitrification nitrogen removal, and biological phosphorus removal. The effluent quality consistently met the Class B standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002), demonstrating stable and reliable treatment performance.

[0016] The main reactor adopts a vertical integrated structure, integrating multiple treatment units into one reactor. It occupies only 1 / 5 to 1 / 3 of the area of ​​traditional constructed wetlands, making it suitable for installation in rural courtyards and open spaces at the entrance of villages, saving land area and reducing costs.

[0017] This device operates with zero energy consumption and no electricity consumption. It utilizes agricultural waste to produce biochar, which has a carbon sequestration effect, truly realizing carbon reduction in the wastewater treatment process and achieving low-carbon and environmentally friendly practices.

[0018] Highly adaptable: The system can flexibly adjust tidal cycles and hydraulic loads to meet the treatment needs of different water qualities and quantities; the design of the auxiliary siphon booster device further improves the system's adaptability to water volume fluctuations, and it can be used to treat water volumes of 1-50m³. 3 / d various types of rural sewage. Attached Figure Description

[0019] Figure 1 This is a plan view illustrating the overall structure of the present invention; Figure 2 This is a top view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the tidal flow-simulated self-siphon system structure in this invention; Figure 4 This is a schematic diagram of the biochar gradient filtration reaction zone structure of the present invention; In the diagram: 1-Main reactor, 2-Water collection tank, 3-Sludge mineralization zone, 4-Biochar gradient filter layer, 401-Honeycomb activated carbon bottom layer, 402-Honeycomb activated carbon middle layer, 403-Honeycomb activated carbon top layer, 404-Stainless steel wire mesh fixing and separating layer, 405-Stainless steel wire mesh and polypropylene geotextile separating layer, 5-Tidal flow flooding zone, 6-Ultra-high protection zone, 7-Ventilation pipe, 8-Inlet pipe, 9-Water distributor, 10-Imitation tidal flow self-siphon system, 101-Siphon inlet pipe, 102-Siphon trigger chamber, 103-Magnetic trigger mechanism, 1031-Permanent magnet fixed base, 1032-Magnetic sealing cover, 1033-Fixing component, 104-Siphon outlet pipe, 11-Outlet pipe, 12-Baffle, 13-One-way breathing valve, 14-Sludge discharge zone. Detailed Implementation

[0020] 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.

[0021] An integrated device for low-carbon treatment of rural sewage, based on simulated tidal flow and biochar gradient coupling, has a treatment capacity of 5m³. 3 / d, applicable to the treatment of domestic sewage from single or joint rural households.

[0022] Please see Figure 1-2 This device includes a main reactor 1, an inlet water distribution system, a simulated tidal flow self-siphon system, a biochar gradient filter layer 4, and an effluent collection system. The main reactor 1 is a vertical cylindrical structure made of fiberglass, with an outer diameter of 2.2m, a total height of 2.0m, and an effective volume of approximately 5.0m³. 3The main reactor 1 is equipped with a partition 12 to divide it into a reaction zone and a water collection tank 2. The reaction zone consists of a sludge mineralization zone 3 with a height of 0-0.3m, a biochar gradient filtration reaction zone 4 with a height of 0.3-1.5m, a tidal flow flooding zone 5 with a height of 1.5-1.7m, and an ultra-high protection zone 6 with a height of 1.7-2.0m.

[0023] The water inlet and distribution system includes an inlet pipe 8 and a water distributor 9. The water distributor 9 is an annular perforated pipe structure, located at the bottom of the biochar gradient filter media layer 4. The pipe diameter is DN50, and water distribution holes with a diameter of 8mm are evenly opened at the bottom with a hole spacing of 100mm.

[0024] The simulated tidal flow self-siphon system 10 includes a siphon inlet pipe 101 placed inside the main reactor, with its inlet end located at the designed low water level of the tidal flow flooding zone 5. A siphon outlet pipe 104 is connected to the outlet water collection system, with its inlet position at least 20 cm lower than the outlet pipe 11. The siphon trigger chamber 102 is a sealed cavity located at the highest point of the siphon inlet pipe 101, and contains a magnetic trigger mechanism 103. The magnetic trigger mechanism 103 includes a permanent magnet fixing base 1031, with a magnetic sealing cover 1032 above the permanent magnet fixing base 1031. The magnetic sealing cover 1032 contains a permanent magnet, and a fixing member 1033 securely connects the magnetic sealing cover 1032 to the permanent magnet fixing base 1031. Figure 3 As shown; Preferably, the permanent magnet fixing base 1031 is an EPDM rubber sealing gasket.

[0025] The one-way breather valve 13 is located at the top of the main reactor 1, allowing air to enter the main reactor but preventing water vapor from overflowing. When the liquid level in the main reactor 1 rises to 1.7m, the gas in the siphon inlet pipe 101 is compressed, generating a pressure difference that triggers the magnetic suction mechanism 103. The magnetic sealing cover 1032 opens, and the liquid level in the siphon inlet pipe 101 rises, generating a siphon effect. The sewage in the tidal flooding zone 5 is rapidly discharged in a short time, forming a tidal receding process. When the liquid level drops to the designed low water level, the one-way breather valve opens, the siphon is broken, and one tidal cycle is completed.

[0026] The total thickness of the biochar gradient filter layer 4 is 1.0m, and the parameters of each layer from bottom to top are as follows: bottom layer 401 of honeycomb activated carbon: 300mm thick, 8mm pore size; middle layer 402 of honeycomb activated carbon: 400mm thick, 4mm pore size; top layer 403 of honeycomb activated carbon: 300mm thick, 1.5mm pore size; stainless steel wire mesh fixing and separating layers 404 are provided between each layer and at the bottom, and stainless steel wire mesh and polypropylene geotextile separating layer 405 with a pore size of 0.2mm are provided at the top. Figure 4 As shown.

[0027] As a preferred method, each layer of biochar was prepared by pyrolysis of rice husks at 400°C under limited oxygen for 3 hours, followed by modification treatment with 20% nitric acid at 60°C for 2 hours, and washing until neutral before use. The biochar had a pH of 7.2-7.8 and a specific surface area of ​​350-650 m². 2 / g.

[0028] The water collection system includes a water collection tank 2 and a water outlet pipe 11, which is connected to a drainage pipe.

[0029] The sludge mineralization zone 3 is located at the bottom of the main reactor 1, and the sludge in the sludge mineralization zone is subjected to static pressure. Upon entering the sludge discharge zone, the sludge mineralization zone 3 is connected to the sludge discharge zone 14 via a connecting pipe. The sludge mineralization zone 3 is connected to the bottom of the independent sludge discharge zone inside the main reactor 1, thereby discharging the sludge from the system.

[0030] Working principle Rural domestic sewage flows by gravity through the collection network and enters through the inlet pipe 8. It is then evenly distributed at the bottom of the biochar gradient filter layer 4 by the water distributor 9. It flows upward through the biochar gradient filter layer 4. In the biochar zone, organic matter is degraded through adsorption and the microorganisms that grow on it. Under the action of microorganisms in each layer, the organic matter is aerobically degraded, ammonia nitrogen is converted into nitrate nitrogen through nitrification, and nitrate nitrogen is converted into nitrogen gas and removed in the anoxic zone through denitrification. Phosphate is adsorbed by biochar.

[0031] After the wastewater enters the tidal flow flooding zone 5, when the liquid level reaches the designed high water level (1.70m), the gas in the siphon inlet pipe 101 is compressed, creating a pressure difference. The magnetic mechanism in the siphon trigger chamber 102 triggers the magnetic sealing cover 1032 in 103 to open, causing the liquid level in the siphon inlet pipe 101 to rise and creating a siphon effect. The wastewater in the tidal flow flooding zone 5 is discharged into the collection tank 2 within 2-3 minutes. Because the drainage speed is much greater than the infiltration speed, the gas in the pores of the filter media is quickly discharged, forming a strong gas suction effect. Fresh air is drawn into the filter media from the top, achieving efficient oxygenation. The wastewater in the collection tank is discharged through the outlet pipe 11. The detached biofilm settles to the bottom sludge mineralization zone 3, where endogenous respiration and anaerobic digestion occur under anaerobic conditions, achieving in-situ sludge reduction. The sludge is then discharged from the system through the sludge discharge zone 14.

[0032] This invention utilizes the principle of tidal flow self-siphoning to achieve automatic periodic drainage and reoxygenation without any power equipment. A dissolved oxygen gradient distribution is created through a biochar gradient filter layer, achieving an organic combination of aerobic, anoxic, and anaerobic environments within the same reactor, completing the entire process of organic matter degradation, nitrogen and phosphorus removal. This invention has significant advantages such as zero-power operation, stable treatment effect, small footprint, low investment, simple operation and maintenance, near-zero sludge discharge, and low carbon emissions, making it particularly suitable for low-cost, low-maintenance treatment of decentralized rural domestic sewage. The effluent quality consistently meets the Class B standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0033] 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. An integrated device for low-carbon treatment of rural sewage, comprising a main reactor (1), an influent distribution system, a simulated tidal flow self-siphon system, a biochar gradient filter layer (4), and an effluent collection system, characterized in that: The main reactor (1) is equipped with a partition (12) to divide it into a reaction zone and a water collection tank (2). The reaction zone consists of a sludge mineralization zone (3), a biochar gradient filtration reaction zone (4), a tidal flow flooding zone (5), and an ultra-high protection zone (6) from bottom to top. The water collection tank is equipped with an outlet pipe (11) to form an outlet water collection system. The tidal flooding zone (5) is equipped with a simulated tidal flow self-siphon system (10). The simulated tidal flow self-siphon system (10) includes a siphon inlet pipe (101) placed inside the main reactor. The upper end of the siphon inlet pipe (101) is provided with a siphon trigger chamber (102). The siphon trigger chamber (102) is provided with a magnetic trigger mechanism (103). The outside of the siphon trigger chamber (102) is connected to a siphon outlet pipe (104) in the water collection tank. The biochar gradient filter layer (4) is located in the middle of the main reactor (1). From bottom to top, it is provided with a honeycomb activated carbon bottom layer (401), a honeycomb activated carbon middle layer (402), and a honeycomb activated carbon top layer (403). A stainless steel wire mesh fixing and separating layer (404) is provided between each layer. The upper end of the biochar gradient filter layer (4) is provided with a stainless steel wire mesh and a polypropylene geotextile separating layer (405), and the bottom is provided with a stainless steel wire mesh fixing and separating layer (404).

2. The integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The water inlet and distribution system includes an inlet pipe (8) located at the bottom of the biochar gradient filter media layer (4). The inlet pipe (8) is connected to a water distributor (9), which is selected as an annular perforated pipe or a radial water distribution structure.

3. The integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The main reactor (1) is equipped with a one-way breathing valve (13) at the top. The one-way breathing valve (13) is connected to the ventilation pipe (7). The other end of the ventilation pipe (7) extends to the outside of the main reactor (1).

4. An integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The siphon triggering chamber (102) is a sealed chamber with a magnetic triggering mechanism (103) inside. The magnetic triggering mechanism (103) includes a permanent magnet fixing base (1031). A magnetic sealing cover plate (1032) is provided above the permanent magnet fixing base. The magnetic sealing cover plate (1032) has a built-in permanent magnet. The magnetic sealing cover plate and the permanent magnet fixing base are fixedly connected by a fixing member (1033). When the liquid level in the tidal flow flooded area (5) rises to the designed high water level of 1.7m, the gas in the siphon inlet pipe (101) is compressed, triggering the magnetic triggering mechanism (103), so that a negative pressure is formed in the siphon pipe (101) to start the siphon effect, and the sewage in the tidal flow flooded area (5) is discharged.

5. An integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The main reactor (1) is a vertical cylindrical or cuboid structure made of fiberglass.

6. An integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The sludge mineralization zone (3) is located at the bottom of the main reactor (1). The sludge mineralization zone (3) is connected to the sludge discharge zone (14) by a connecting pipe. The sludge mineralization zone (3) is connected to the bottom of the independent sludge discharge zone inside the main reactor (1) to discharge the sludge into the system.

7. An integrated device for low-carbon treatment of rural sewage according to claim 1, characterized in that: The activated carbon used in the bottom layer (401), middle layer (402), and top layer (403) of the honeycomb activated carbon is all made from rice husks through oxygen-limited pyrolysis at 400 degrees Celsius for 3 hours, followed by modification treatment with 20% nitric acid at 60 degrees Celsius for 2 hours, and then washed until neutral before use. The biochar has a pH value of 7.2-7.8 and a specific surface area of ​​not less than 350 m². 2 / g.

8. An integrated device for low-carbon treatment of rural sewage according to claim 7, characterized in that: The honeycomb activated carbon bottom layer (401) has a thickness of 300 mm and a pore size of 8 mm; The honeycomb activated carbon intermediate layer (402) has a thickness of 400 mm and a pore size of 4 mm; The upper layer (403) of the honeycomb activated carbon has a thickness of 300 mm and a pore size of 1.5 mm.

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