Low-emission organic manure fermentation method based on agriculture, forestry and animal husbandry waste and vegetable and fruit garbage

Abstract

The invention relates to a low-emission organic manure fermentation method based on agriculture, forestry and animal husbandry wastes and vegetable and fruit wastes, which comprises the following steps: mixing industrial waste residues, the agriculture, forestry and animal husbandry wastes and the vegetable and fruit wastes in a mixing bin through an automatic transmission process; the method comprises the following steps: carrying out anaerobic fermentation, cooling, spraying water mist and nitrogen to treat biogas, carrying out phase separation, treating biogas residues, treating biogas slurry, mixing the biogas residues and the biogas slurry, and packaging to obtain an organic manure product. The organic manure product with high water retention rate, high trace elements and high soil moisture conservation effect for desert crops planted in the desert area is obtained, emission of harmful gas is greatly reduced in the preparation process, and the preparation process does not cause pollution to the atmosphere.

Description

Technical Field

[0001] This invention relates to the field of waste treatment and manure fermentation technology, specifically to a low-emission organic manure fermentation method based on agricultural, forestry, and animal husbandry waste and vegetable and fruit waste. Background Technology

[0002] In desertification control practices, drought-resistant pioneer plants such as sea buckthorn, saxaul, and sand willow have become key species for ecological restoration. However, the cultivation and maintenance of these plants face unique challenges in nutrient supply: the average annual precipitation in typical desert areas of Northwest my country is less than 200 mm, while evaporation reaches 2400-3100 mm, leading to inefficiencies in conventional fertilization systems due to extreme environmental conditions. Traditional fertilizer nutrient release is mismatched with the hydrothermal conditions of arid regions: taking mainstream slow-release fertilizers as an example, their nitrogen, phosphorus, and potassium release cycles are positively correlated with water activity. In sandy soils with a moisture content of less than 8% (according to measured data from the Northwest Institute of the Chinese Academy of Sciences), the nitrogen release rate decreases by 72%-85%, resulting in an actual nutrient utilization rate of less than 15%. Meanwhile, existing conventional fertilizers lack physical water-retention properties. Although polyacrylamide-based water-retaining agents are widely used in agriculture, their water absorption rate (300-500 g / g) contradicts their adaptability to the 40°C diurnal temperature range in desert environments. Tests have shown that at 50°C, their water retention period is shortened to 23% of that at room temperature. Furthermore, existing fertilizers suffer from a significant imbalance in micronutrient supply. Drought-resistant plants have evolved specific nutritional requirements to adapt to stressful environments. For example, Haloxylon ammodendron requires 8-10 times more boron than ordinary crops (《Arid Zone Plant Nutrition》2020 edition), while conventional compound fertilizers contain only 0.02%-0.05% boron, and the pH value of sandy soils is generally above 8.5, resulting in an available boron content of less than 30%.

[0003] Existing research addresses these technical problems by improving sustained-release performance. One approach involves polymer coating technology (such as polyvinyl alcohol-starch copolymer coating). While this technology can extend the nitrogen release period to 60-80 days, the membrane material is susceptible to damage under strong ultraviolet radiation (average annual radiation in desert areas is 6200 MJ / m²). 2 Photo-oxidative degradation occurs, leading to premature failure of the controlled-release function. Compensating for nutrient loss by increasing fertilization frequency not only increases costs by 240-300 yuan per acre but also exacerbates soil salinization (experimental data from the Kubuqi Desert in Inner Mongolia show that three consecutive years of application of ordinary compound fertilizer increased the EC value of topsoil from 0.38 mS / cm to 1.52 mS / cm). While existing soil improvement technologies using biochar-based fertilizers can increase soil organic matter content (an application rate of 10 t / ha can increase organic matter by 0.8%), their specific surface area (120-250 m²) is limited. 2Carbon-based fertilizers (0.05-0.25 mm in diameter) are difficult to form a stable complex with the fine sand commonly found in deserts. Under wind erosion conditions of level 7 or higher, the loss rate of carbon-based fertilizers reaches 67%-83% after 6 months of application. This multiple mismatch between materials, environment, and plants results in a plant survival rate of less than 40% in current desert planting projects (compared to a survival rate of over 85% in humid areas), severely hindering the progress of desertification control.

[0004] Meanwhile, for agricultural waste containing moisture, such as straw, vegetable roots, and especially fruit and vegetable residues, generated during agricultural, forestry, and animal husbandry production, as well as kitchen waste (which accounts for 40%-60% of municipal solid waste), the industry generally adopts two mainstream treatment methods: landfill and anaerobic fermentation. In engineering practice, while landfill treatment has the advantage of being simple to operate, it occupies a large amount of land resources and poses a risk of leachate pollution. More importantly, it fails to achieve the resource utilization of organic matter. In contrast, anaerobic fermentation technology converts organic matter into biogas and organic manure through microbial degradation, demonstrating significant advantages in energy recovery.

[0005] However, existing fermentation processes face two key technological bottlenecks: First, biogas treatment systems suffer from seasonal supply-demand imbalances. According to data from the Ministry of Agriculture and Rural Affairs on biogas project operations in 2022, biogas production rates during the summer high-temperature period increase by 50-70% compared to winter, while urban and rural gas demand decreases by about 40% during the same period. This misalignment between peak production and off-peak usage forces operating companies to adopt a temporary storage scheme combining two-stage purification (desulfurization, dehydration, and decarbonization) with high-pressure storage tanks (usually maintained at 3.0-4.0 MPa pressure), resulting in an increase of 0.8-1.2 yuan per cubic meter of biogas storage cost, significantly weakening the project's economic viability. Second, emergency emissions pose environmental risks. When storage devices reach their design capacity limit, some treatment plants have to resort to flare combustion or direct emission to dispose of excess biogas, which not only causes about 35% methane escape (methane's greenhouse effect is 28 times that of carbon dioxide) but also contradicts my country's carbon emission reduction targets.

[0006] It is particularly important to note that the generation of agricultural and forestry organic waste, as well as fruit and vegetable waste, exhibits significant seasonal characteristics. For example, the peak generation period for wheat straw in North China is June and July, while the peak generation period for fruit and vegetable processing residues in the south is August and September. These periods highly overlap with the low demand for biogas. Traditional treatment methods face the dual pressures of "soaring storage costs" and "environmental violation risks" during these periods.

[0007] A deeper technical contradiction lies in the fact that existing technological systems focus on the downstream biogas utilization stage, failing to establish a comprehensive control mechanism based on the characteristics of the upstream materials. The high cellulose (35-50%) and high moisture content (60-75%) characteristics of agricultural and forestry waste, combined with the abundant starch and fat components in vegetable and fruit waste and kitchen waste, form a complex material system. This multi-component matrix makes it difficult to achieve component adaptation and gas production control in traditional fermentation processes, ultimately leading to a disconnect between the characteristics of the biogas produced and market demand.

[0008] Therefore, developing a treatment system capable of analyzing raw material characteristics, regulating the fermentation process, and dynamically adapting products, applicable to manure production in desert areas, and ensuring the environmental friendliness of the treatment process through process chain innovation, has become a pressing technical challenge to overcome in improving the resource utilization level of biomass waste. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention proposes a low-emission organic manure fermentation method based on agricultural, forestry, and animal husbandry waste and vegetable and fruit waste, which can produce manure applicable to desert areas.

[0010] The agricultural, forestry, and animal husbandry waste and vegetable and fruit waste targeted by this invention are agricultural, forestry, and animal husbandry waste excluding vegetable and fruit waste.

[0011] Specifically, this is achieved through the following technical solution:

[0012] A low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste includes the following steps:

[0013] S1. Industrial waste residue is crushed into particles with a particle size of 0.6 to 1.5 cm, and then mixed with agricultural, forestry and animal husbandry waste and vegetable and fruit waste at a volume ratio of (0.9 to 1.1):(5 to 10). The mixture is then put into a mixing chamber for stirring to obtain a mixed material.

[0014] S2, after stirring in step S1, the mixed material is transferred to a closed fermentation tank for anaerobic fermentation for 15-20 days to obtain the fermentation product.

[0015] S3, the fermentation product obtained in step S2 is transferred to the cooling chamber, the temperature in the cooling chamber is reduced to -8 to 5°C, and a mixture of nitrogen and water mist is sprayed in at the same time.

[0016] S4. The material cooled in step S3 is conveyed to the phase separation chamber. A gas exhaust pipe is installed at the top of the phase separation chamber to discharge the gas. In the phase separation chamber, the biogas residue is conveyed to the composting chamber and the biogas slurry is conveyed to the aeration tank.

[0017] S5. Add composting agent and urea to the biogas residue transferred to the composting bin in step S4, adjust the carbon-nitrogen ratio to (20-30):1, maintain the temperature in the composting bin at 50-60℃, and compost for 9-16 days to obtain base fertilizer.

[0018] S6, the biogas slurry from step S4 is transferred to the aeration tank for oxygenation and aeration for 10-12 hours.

[0019] S7. The aerated biogas slurry and the base fertilizer obtained in step S5 are placed into the finished product silo for mixing and stirring to obtain mixed fertilizer.

[0020] S8 involves shaping the mixed fertilizer into balls with a diameter of 2-5 cm and then packaging them to obtain organic manure products.

[0021] Preferably, the industrial waste residue is blast furnace slag, converter slag, electric furnace slag, or sintering red mud slag.

[0022] Preferably, agricultural, forestry, and livestock waste and vegetable and fruit waste are one or more of the following: agricultural waste, forestry waste, livestock waste, or vegetable and fruit waste. The agricultural waste is one or more of the following: crop residues or water-containing wastes from grain processing, excluding vegetable and fruit waste. The forestry waste is one or more of the following: branch and leaf residues, tree bark, sawdust, or wood chip residues. The livestock waste is one or more of the following: animal excrement, dead animal remains, and treatment liquid or waste feed residues. The vegetable and fruit waste is one or two of the following: vegetable residues or fruit residues generated during agricultural production or in daily life.

[0023] Preferably, the stirring time in step S1 is 5 to 13 hours, and the stirring shaft speed is 38 to 65 revolutions per minute.

[0024] Preferably, the anaerobic fermentation conditions in step S2 are: a temperature of 45–55°C.

[0025] As a preferred option, during the anaerobic fermentation process in step S2, the material is turned over once every 6 to 8 days, with each turn lasting 5 to 10 minutes.

[0026] Preferably, a one-way valve facing the cooling chamber is provided between the closed fermentation tank in step S2 and the cooling chamber in step S3. When the gas pressure in the closed fermentation tank exceeds the maximum gas pressure threshold, the one-way valve is opened to discharge the gas generated in the closed fermentation tank into the cooling chamber. When the gas pressure in the closed fermentation tank is lower than the minimum gas pressure threshold, the one-way valve is closed. The maximum gas pressure threshold is 0.18 to 0.38 MPa, and the minimum gas pressure threshold is 0.09 to 0.10 MPa.

[0027] Preferably, in step S4, the gas is discharged through a gas discharge pipe, and the discharged gas is either ignited or discharged into a gas storage tank for storage.

[0028] Preferably, the composting agent in step S5 is EM agent or Bacillus subtilis; 1-2 kg of composting agent is added per ton of biogas residue; 3-8 kg of urea is added per ton of biogas residue.

[0029] Preferably, materials are moved between each step using an automated transmission system.

[0030] A low-emission manure fermentation device based on agricultural, forestry and animal husbandry waste and vegetable and fruit waste includes a mixing chamber, a closed fermentation tank, a cooling chamber, a phase separation chamber, a composting chamber, an aeration tank, and a finished product chamber.

[0031] The mixing chamber is equipped with a stirring shaft, and the stirring blades of the stirring shaft are cutting blades.

[0032] The sealed fermentation tank is equipped with heating rods, stirring rods, a temperature controller, a one-way valve, and a pressure sensor. The heating rods are arranged in multiple layers within the sealed fermentation tank, and a stirring rod is located below the heating rods to agitate the material. The temperature controller is used to detect the temperature inside the sealed fermentation tank and control the temperature of the heating rods. The one-way valve is located at the top of the side wall of the sealed fermentation tank and is connected to the cooling chamber through a pipe. The pressure sensor is used to monitor the pressure inside the sealed fermentation tank and control the opening and closing of the one-way valve.

[0033] The cooling chamber is equipped with a compressor for cooling. A nitrogen generator, an atomizing device, and a mixing and spraying component are installed on the outer wall of the cooling chamber. The nitrogen generator is a nitrogen generator or a nitrogen storage bottle. The atomizing device is used to atomize the water. The mixing and spraying component includes a mixing chamber and a nozzle. The inlet of the mixing chamber is connected to both the nitrogen generator and the atomizing device. The inlet of the nozzle is connected to the outlet of the mixing chamber. The outlet of the nozzle is located inside the cooling chamber. An air pump is installed on the nozzle to pressurize the mixed atomized gas inside the nozzle and spray it out through the nozzle outlet.

[0034] The phase separation chamber is equipped with a gas discharge pipe, a solid-liquid separation screen, a material inlet, a biogas residue discharge outlet, and a biogas slurry discharge outlet. The gas discharge pipe is located on the fixed wall of the phase separation chamber and is also equipped with a one-way valve. When the gas pressure inside the phase separation chamber is greater than atmospheric pressure, the one-way valve is opened by the gas, and the gas is discharged through the gas discharge pipe. The solid-liquid separation screen is inclined inside the phase separation chamber, and the material inlet is located on the side wall of the phase separation chamber above the lower solid-liquid separation screen. The material inlet is connected to the material discharge outlet of the cooling chamber. The biogas residue discharge outlet is located on the side wall of the phase separation chamber above the higher solid-liquid separation screen, and the biogas slurry discharge outlet is located on the side wall of the phase separation chamber below the higher solid-liquid separation screen.

[0035] The composting bin is used to compost the biogas residue discharged from the phase separation bin by adding composting bacteria and urea.

[0036] The aeration tank is a blower aeration tank. An aeration pipe is installed at the bottom of the aeration tank, and a blower is connected to the aeration pipe. A disc-shaped microporous aeration head is installed at the outlet end of the aeration pipe. The pore diameter of the microporous aeration head is 0.1-3mm. The air inlet of the blower is connected to the outside air. The air is pressurized by the blower and enters the bottom of the aeration tank through the aeration pipe. The air is then divided into bubbles with a diameter of 0.1-3mm by the microporous aeration head and discharged into the biogas slurry contained in the aeration tank. As the bubbles rise, oxygen dissolves in the biogas slurry, thus achieving oxygenation and aeration.

[0037] The finished product warehouse is equipped with a rounding machine and a packaging machine. The rounding machine is used to round the materials discharged into the finished product warehouse. After the materials are rounded to a diameter of 2-5cm, they are discharged into the packaging machine. The packaging machine wraps the outer skin of the material to form the product.

[0038] Preferably, the apparatus is used to implement the above-mentioned low-emission organic manure fermentation method based on agricultural, forestry and animal husbandry waste and vegetable and fruit waste.

[0039] Preferably, the mixing chamber, the closed fermentation tank, the cooling chamber, and the phase separation chamber are all closed structures.

[0040] Preferably, a biogas storage tank or an igniter is provided outside the gas emission pipe.

[0041] Preferably, the outer packaging is made of straw-based packaging paper or bamboo fiber molded packaging paper.

[0042] The technical effects of this invention are as follows:

[0043] 1. Because industrial waste (mainly steel slag such as blast furnace slag and converter slag) produces numerous and densely packed pores during steelmaking, and also contains trace elements such as boron, iron, and zinc, this invention achieves a spherical organic manure product as a mixture of industrial waste and fermented organic manure by mixing and fermenting industrial waste crushed to a certain particle size with agricultural, forestry, and livestock waste and vegetable and fruit waste. This is achieved by preserving the presence of liquid and gaseous materials in the organic manure product during preparation, while allowing some liquid and gaseous materials to escape during transportation and storage. This allows the dense pores in the industrial waste residue to reappear during use. When buried under desert crops, the liquid and gaseous materials are slowly absorbed by the plants, just like solid manure. Furthermore, during the degradation process, the fermented manure further releases the porous structure of the industrial waste residue, enhancing the water absorption and retention effects of the pores. As a result, this organic manure product can achieve multiple functions such as water retention, moisture conservation, and efficient supplementation of fertilizers and trace elements in specific planting sites like desertification, greatly improving the survival rate and efficient growth of plants grown in desertification areas.

[0044] 2. This invention, after anaerobic fermentation, achieves efficient removal of hydrogen sulfide from the biogas by cooling the entire product and injecting water mist and nitrogen. (The low temperature and water mist adsorb and remove large amounts of H2S, allowing H2S to exist in liquid form within the material.) Simultaneously, carbon dioxide from the biogas is fixed into the liquid material. Combined with nitrogen injection, the oxygen concentration in the biogas is reduced, ensuring the coexistence of gas, liquid, and solid components even at above-atmospheric pressure. The pressure setting above atmospheric pressure and the low temperature setting allow some biogas to remain in the material gaps, significantly reducing the biogas emission pressure. Subsequent biogas emissions, processed through combustion or temporary storage, also exhibit significantly reduced air pollution due to the efficient removal of hydrogen sulfide, resulting in lower emissions. This improves the environmental friendliness of the production process.

[0045] 3. This invention first rolls the final product into spheres, then packages them with degradable paper. Because the fermentation process uses low temperature, water mist, and nitrogen to fix some biogas and its components into the biogas slurry or residue, and then processes the residue and slurry separately before combining them, the resulting spheres have a very high moisture content. These spheres are then packaged with degradable paper, thus forming the organic manure product. The degradable paper packaging prevents excessive loss of moisture and trace amounts of gaseous fertilizer during transportation and temporary storage. The straw-based packaging paper or bamboo fiber molded packaging is relatively inexpensive yet meets the requirements for degradable packaging of organic manure. When applied to desertification scenarios, the degradable paper is prone to partial tearing, with other parts degrading slowly. Due to the high moisture content, the nutrients are more easily absorbed by desert plants, and its high water content and water-holding capacity make it more suitable for desert plant applications. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the layout of a low-emission organic manure fermentation device based on agricultural, forestry, and animal husbandry waste and vegetable and fruit waste, according to one embodiment of the present invention.

[0047] Wherein: 001 - Mixing chamber; 101 - Stirring shaft;

[0048] 002-Sealed fermentation tank; 201-Heating rod; 202-Stirring rod; 203-One-way valve;

[0049] 003-Cooling chamber; 301-Nitrogen generator; 302-Atomizing device; 303-Mixing chamber; 304-Nozzle; 305-Compressor;

[0050] 004-Phase separation chamber; 401-Solid-liquid separation screen; 402-Sludge discharge port; 403-Sludge discharge port;

[0051] 051 - Composting bin;

[0052] 052-Aeration tank; 521-Microporous aeration head; 522-Aeration pipe; 523-Blower;

[0053] 006-Finished Goods Warehouse; 601-Rolling Machine; 602-Packaging Machine. Detailed Implementation

[0054] The process technology solution of the present invention will be further described below with reference to embodiments and accompanying drawings. Unless otherwise specified, each feature is merely one example of a series of equivalent or similar features. These embodiments are merely for the purpose of aiding understanding the present invention and should not be considered as specific limitations thereof.

[0055] The technical solution of the present invention will be further described in conjunction with the embodiments:

[0056] Example 1

[0057] The low-emission organic manure fermentation device based on agricultural, forestry, and livestock waste and vegetable and fruit waste in this embodiment is as follows: Figure 1 The layout is as shown, including a mixing chamber, a closed fermentation tank, a cooling chamber, a phase separation chamber, a composting chamber, an aeration tank, and a finished product chamber.

[0058] The mixing chamber is equipped with a stirring shaft, and the stirring blades of the stirring shaft are cutting blades. These cutting blades, in conjunction with a specific rotation speed during the stirring process, can cut and crush the biomass.

[0059] The sealed fermentation tank is equipped with heating rods, stirring rods, a temperature controller, a one-way valve, and a pressure sensor. The heating rods are arranged in multiple layers within the sealed fermentation tank, and a stirring rod is located below the heating rods to agitate the material. The temperature controller is used to detect the temperature inside the sealed fermentation tank and control the temperature of the heating rods. The one-way valve is located at the top of the side wall of the sealed fermentation tank and is connected to the cooling chamber through a pipe. The pressure sensor is used to monitor the pressure inside the sealed fermentation tank and control the opening and closing of the one-way valve.

[0060] The cooling chamber is equipped with a compressor for cooling. A nitrogen generator, an atomizing device, and a mixing and spraying component are installed on the outer wall of the cooling chamber. The nitrogen generator is a nitrogen generator or a nitrogen storage bottle. The atomizing device is used to atomize the water. The mixing and spraying component includes a mixing chamber and a nozzle. The inlet of the mixing chamber is connected to both the nitrogen generator and the atomizing device. The inlet of the nozzle is connected to the outlet of the mixing chamber. The outlet of the nozzle is located inside the cooling chamber. An air pump is installed on the nozzle to pressurize the mixed atomized gas inside the nozzle and spray it out through the nozzle outlet.

[0061] The phase separation chamber is equipped with a gas discharge pipe, a solid-liquid separation screen, a material inlet, a biogas residue discharge outlet, and a biogas slurry discharge outlet. The gas discharge pipe is located on the fixed wall of the phase separation chamber and is also equipped with a one-way valve. When the gas pressure inside the phase separation chamber is greater than atmospheric pressure, the one-way valve is opened by the gas, and the gas is discharged through the gas discharge pipe. The solid-liquid separation screen is inclined inside the phase separation chamber, and the material inlet is located on the side wall of the phase separation chamber above the lower solid-liquid separation screen. The material inlet is connected to the material discharge outlet of the cooling chamber. The biogas residue discharge outlet is located on the side wall of the phase separation chamber above the higher solid-liquid separation screen, and the biogas slurry discharge outlet is located on the side wall of the phase separation chamber below the higher solid-liquid separation screen.

[0062] The composting bin is used to compost the biogas residue discharged from the phase separation bin by adding composting bacteria and urea.

[0063] The aeration tank is a blower aeration tank. An aeration pipe is installed at the bottom of the aeration tank, and a blower is connected to the aeration pipe. A disc-shaped microporous aeration head is installed at the outlet end of the aeration pipe. The pore diameter of the microporous aeration head is 0.1-3mm. The air inlet of the blower is connected to the outside air. The air is pressurized by the blower and enters the bottom of the aeration tank through the aeration pipe. The air is then divided into bubbles with a diameter of 0.1-3mm by the microporous aeration head and discharged into the biogas slurry contained in the aeration tank. As the bubbles rise, oxygen dissolves in the biogas slurry, thus achieving oxygenation and aeration.

[0064] The finished product warehouse is equipped with a rounding machine and a packaging machine. The rounding machine is used to round the materials discharged into the finished product warehouse. After the materials are rounded to a diameter of 2-5cm, they are discharged into the packaging machine. The packaging machine wraps the outer skin of the material to form the product.

[0065] like Figure 1 As shown, the mixing chamber, the closed fermentation tank, the cooling chamber, and the phase separation chamber are all closed structures.

[0066] The gas emission pipe is equipped with a biogas storage tank or an igniter for subsequent biogas treatment. The outer packaging is made of straw-based packaging paper or bamboo fiber molded packaging.

[0067] Example 2

[0068] This embodiment illustrates the process of processing using the device of Embodiment 1, and the overall process is as follows. Figure 1 As shown, it includes the following steps:

[0069] S1. Blast furnace slag is crushed into particles with a diameter of 0.6–1.5 cm (the average particle size in this embodiment is 1 cm), and then mixed with agricultural, forestry, and livestock waste and vegetable and fruit waste at a volume ratio of 1:6. The mixture is then fed into a mixing chamber for stirring for 10 hours at a stirring shaft speed of 60 rpm. The resulting mixture is a stirred material. The agricultural, forestry, and livestock waste and vegetable and fruit waste are agricultural waste, forestry waste, livestock waste, or vegetable and fruit waste. The agricultural waste is a mixture of crop residues, fruit and vegetable residues, or water-containing waste from grain processing; the forestry waste is a mixture of branches, leaves, flowers, fruits, bark, sawdust, or wood chips; and the livestock waste is a mixture of animal excrement, dead animal remains, and treatment liquid or waste feed residue. Since this embodiment directly collects agricultural, forestry, and livestock waste and vegetable and fruit waste, no specific quantity of the waste is quantified.

[0070] S2, after stirring in step S1, the mixed material is transferred to a closed fermentation tank for anaerobic fermentation for 18 days at a temperature of 50°C. The material is turned over once every 7 days for 8 minutes each time to obtain the fermentation product.

[0071] S3, the fermentation product obtained in step S2 is transferred to the cooling chamber, the temperature in the cooling chamber is reduced to 2°C, and a mixture of nitrogen and water mist is sprayed in at the same time.

[0072] A one-way valve facing the cooling chamber is installed between the closed fermentation tank in step S2 and the cooling chamber in step S3. When the gas pressure in the closed fermentation tank exceeds 0.25 MPa, the one-way valve is opened to discharge the gas generated in the closed fermentation tank into the cooling chamber. When the gas pressure in the closed fermentation tank is lower than 0.10 MPa, the one-way valve is closed.

[0073] S4. The material cooled in step S3 is conveyed to the phase separation chamber. A gas exhaust pipe is installed at the top of the phase separation chamber to discharge gas. The discharged gas is either ignited or stored in a gas storage tank. In the phase separation chamber, the biogas residue is conveyed to the composting chamber, and the biogas slurry is conveyed to the aeration tank.

[0074] S5. Add EM bacteria and urea to the biogas residue transferred to the composting bin in step S4. Add 1.5 kg of composting agent and 6 kg of urea per ton of biogas residue. Adjust the carbon-nitrogen ratio to 25:1 and maintain the temperature in the composting bin at 55°C. Compost for 12 days to obtain base fertilizer.

[0075] S6, the biogas slurry from step S4 is transferred to the aeration tank for oxygenation and aeration for 12 hours.

[0076] S7. The aerated biogas slurry and the base fertilizer obtained in step S5 are placed into the finished product silo for mixing and stirring to obtain mixed fertilizer.

[0077] S8. After the mixed fertilizer is formed into balls with a diameter of 3.8cm, it is packaged to obtain the organic manure product.

[0078] Comparative Example 1

[0079] This comparative example is used to compare comparative data with those using a cooling chamber. The other settings of this comparative example are the same as in Examples 1 and 2, except that a cooling chamber is not used; that is, the cooling chamber of Example 1 is removed, and step S3 of Example 2 is cancelled. Comparative data is accumulated using a small-scale test chamber. After one cycle (30 days) of operation, the biogas emission of this comparative example is 105 m³. 3(Methane volume concentration approximately 63%, hydrogen sulfide volume approximately 2.8%, carbon dioxide volume approximately 31%, nitrogen volume approximately 2.1%, oxygen volume approximately 0.25%), the final packaged organic manure product weighed 663 kg. Example 1, also equipped with a cooling chamber, used the same 1.16 tons of raw materials (including 1 ton of agricultural, forestry, and livestock waste and vegetable / fruit waste), and after one cycle (30 days), the biogas emission was 68 m³. 3 (Methane concentration approximately 65%, hydrogen sulfide volume approximately 0.1%, carbon dioxide volume approximately 8%, nitrogen volume approximately 26.8%, and oxygen volume approximately 0.06%), the final packaged organic manure product weighed 672 kg. From the product alone, it can be seen that after the cooling chamber treatment specifically designed in this invention, the amount of biogas emitted during the production stage was reduced by nearly one-third, while the organic manure product increased by approximately 0.2%. Furthermore, due to the cooling, water mist, and nitrogen spraying treatment, the composition of the biogas produced decreased, with hydrogen sulfide, carbon dioxide, and oxygen reduced, replaced by nitrogen. This greatly facilitates the subsequent treatment and utilization of biogas (since hydrogen sulfide combustion produces sulfur dioxide, direct combustion would have adverse effects on the atmosphere; at the same time, the further reduction of oxygen content in the mixed gas ensures the safety of subsequent biogas treatment processes).

[0080] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste, characterized in that, The steps include: S1, crush industrial waste residue into particles with a particle size of 0.6 to 1.5 cm, then mix it with agricultural, forestry and animal husbandry waste and vegetable and fruit waste at a volume ratio of (0.9 to 1.1):(5 to 10), and then put them into a mixing chamber for stirring to obtain a mixed material; S2, after stirring in step S1, the mixed material is transferred to a closed fermentation tank for anaerobic fermentation for 15-20 days to obtain the fermentation product. S3, the fermentation product obtained in step S2 is transferred to the cooling chamber, the temperature in the cooling chamber is reduced to -8 to 5°C, and a mixture of nitrogen and water mist is sprayed in at the same time. S4. The material cooled in step S3 is conveyed to the phase separation chamber. A gas exhaust pipe is installed at the top of the phase separation chamber. Gas is discharged through the gas exhaust pipe. In the phase separation chamber, the biogas residue is conveyed to the composting chamber and the biogas slurry is conveyed to the aeration tank. S5, add composting agent and urea to the biogas residue transferred to the composting bin in step S4, adjust the carbon-nitrogen ratio to (20-30):1, maintain the temperature in the composting bin at 50-60℃, compost for 9-16 days to obtain base fertilizer; S6, the biogas slurry from step S4 is transferred to the aeration tank for oxygenation and aeration for 10-12 hours; S7, the aerated biogas slurry and the base fertilizer obtained in step S5 are put into the finished product silo for mixing and stirring to obtain mixed fertilizer; S8 involves shaping the mixed fertilizer into balls with a diameter of 2-5 cm and then packaging them to obtain organic manure products.

2. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 1, characterized in that, The industrial waste residue is blast furnace slag, converter slag, electric furnace slag, or sintering red mud slag.

3. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 1 or 2, characterized in that, The agricultural, forestry, and animal husbandry waste and vegetable and fruit waste are one or more of the following: agricultural waste, forestry waste, animal husbandry waste, or vegetable and fruit waste. The agricultural waste is one or more of the following: crop residues or water-containing wastes from grain processing, excluding vegetable and fruit waste. The forestry waste is one or more of the following: branch and leaf flower residues, bark, sawdust, or wood chip residues. The animal husbandry waste is one or more of the following: animal excrement, dead animal remains, and treatment liquid or waste feed residues. The vegetable and fruit waste is one or two of the following: vegetable residues or fruit residues generated during agricultural production or in daily life.

4. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 1 or 2, characterized in that, The stirring time in step S1 is 5 to 13 hours, and the stirring shaft speed is 38 to 65 revolutions per minute.

5. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 1 or 2, characterized in that, The anaerobic fermentation conditions in step S2 are: a temperature of 45–55°C; During the anaerobic fermentation process in step S2, the material is turned over once every 6 to 8 days, and each time it lasts for 5 to 10 minutes. A one-way valve facing the cooling chamber is installed between the closed fermentation tank in step S2 and the cooling chamber in step S3. When the gas pressure in the closed fermentation tank exceeds the maximum gas pressure threshold, the one-way valve is opened to discharge the gas generated in the closed fermentation tank into the cooling chamber. When the gas pressure in the closed fermentation tank is lower than the minimum gas pressure threshold, the one-way valve is closed. The maximum gas pressure threshold is 0.18 to 0.38 MPa, and the minimum gas pressure threshold is 0.09 to 0.10 MPa.

6. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 5, characterized in that, In step S4, the gas is discharged through the gas discharge pipe, and the discharged gas is either ignited or discharged into a gas storage tank for storage. The materials are moved between each step using an automated transmission system.

7. The low-emission organic manure fermentation method based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 6, characterized in that, The composting agent in step S5 is EM agent or Bacillus subtilis; 1-2 kg of composting agent is added per ton of biogas residue; 3-8 kg of urea is added per ton of biogas residue.

8. A low-emission manure fermentation device based on agricultural, forestry, and livestock waste and vegetable and fruit waste, characterized in that, The apparatus is used to implement the low-emission organic manure fermentation method based on agricultural, forestry and animal husbandry waste and vegetable and fruit waste as described in any one of claims 1 to 7, and includes a mixing chamber, a closed fermentation tank, a cooling chamber, a phase separation chamber, a composting chamber, an aeration tank, and a finished product chamber. The mixing chamber is equipped with a stirring shaft, and the stirring blades of the stirring shaft are cutting blades; The sealed fermentation tank is equipped with heating rods, stirring rods, a temperature controller, a one-way valve, and a pressure sensor. The heating rods are arranged in multiple layers within the sealed fermentation tank, and a stirring rod is located below the heating rods to agitate the material. The temperature controller is used to detect the temperature inside the sealed fermentation tank and control the temperature of the heating rods. The one-way valve is located at the top of the side wall of the sealed fermentation tank and is connected to the cooling chamber through a pipe. The pressure sensor is used to monitor the pressure inside the sealed fermentation tank and control the opening and closing of the one-way valve. The cooling chamber is equipped with a compressor for cooling the chamber. A nitrogen generator, an atomizing device, and a mixing and spraying component are installed on the outer wall of the cooling chamber. The nitrogen generator is a nitrogen generator or a nitrogen storage bottle. The atomizing device is used to atomize the water. The mixing and spraying component includes a mixing chamber and a nozzle. The inlet of the mixing chamber is connected to both the nitrogen generator and the atomizing device. The inlet of the nozzle is connected to the outlet of the mixing chamber. The outlet of the nozzle is located inside the cooling chamber. An air pump is installed on the nozzle to pressurize the mixed atomized gas inside the nozzle and spray it out through the nozzle outlet. The phase separation chamber is equipped with a gas discharge pipe, a solid-liquid separation screen, a material inlet, a biogas residue discharge outlet, and a biogas slurry discharge outlet. The gas discharge pipe is located on the fixed wall of the phase separation chamber and is also equipped with a one-way valve. When the gas pressure inside the phase separation chamber is greater than atmospheric pressure, the one-way valve is opened by the gas and the gas is discharged through the gas discharge pipe. The solid-liquid separation screen is inclined inside the phase separation chamber, and the material inlet is located on the side wall of the phase separation chamber above the lower solid-liquid separation screen. The material inlet is connected to the material discharge outlet of the cooling chamber. The biogas residue discharge outlet is located on the side wall of the phase separation chamber above the higher solid-liquid separation screen, and the biogas slurry discharge outlet is located on the side wall of the phase separation chamber below the higher solid-liquid separation screen. The composting bin is used to compost the biogas residue discharged from the phase separation bin by adding composting bacteria and urea. The aeration tank is a blower aeration tank. An aeration pipe is installed at the bottom of the aeration tank, and a blower is connected to the aeration pipe. A disc-shaped microporous aeration head is installed at the outlet end of the aeration pipe. The pore size of the microporous aeration head is 0.1-3mm. The air inlet of the blower is connected to the outside air. The air is pressurized by the blower and enters the bottom of the aeration tank through the aeration pipe. The air is then divided into bubbles with a diameter of 0.1-3mm by the microporous aeration head and discharged into the biogas slurry contained in the aeration tank. During the rising of the bubbles, oxygen dissolves in the biogas slurry, thus achieving oxygenation and aeration. The finished product warehouse is equipped with a rounding machine and a packaging machine. The rounding machine is used to round the materials discharged into the finished product warehouse. After the materials are rounded to a diameter of 2-5cm, they are discharged into the packaging machine. The packaging machine wraps the outer skin of the material to form the product.

9. The low-emission manure fermentation device based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 8, characterized in that, The mixing chamber, the closed fermentation tank, the cooling chamber, and the phase separation chamber are all closed structures.

10. The low-emission manure fermentation device based on agricultural, forestry, and livestock waste and vegetable and fruit waste according to claim 8 or 9, characterized in that, The gas emission pipe is equipped with a biogas storage tank or an igniter. The outer packaging is made of straw-based packaging paper or bamboo fiber molded packaging paper.

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