Complex microbial inoculant for large-scale livestock and poultry manure and straw mixed compost maturity and high-temperature composting method

Abstract

The invention provides a complex microbial inoculant for large-scale livestock and poultry manure and straw mixed compost maturity and a high-temperature composting method, and belongs to the technical field of composting methods. The invention provides the high-temperature complex microbial inoculant suitable for large-scale compost fermentation, and the complex microbial inoculant has the advantages of good high-temperature resistance, long survival time in the composting process and capability of fully decomposing and fermenting materials; according to the fermentation method disclosed by the invention, a long-time continuous high-temperature environment can be obtained in a pile body, so that a pile body material can be fully fermented and decomposed, and meanwhile, the stability of the high-temperature environment in a pile body fermentation process can be well controlled and the quality of an organic fertilizer can be improved by combining the ventilation equipment disclosed by the invention.

Description

Technical Field

[0001] The invention belongs to the technical field of composting methods, and in particular relates to a composite bacterial agent for composting large-scale livestock and poultry excrement and straw and a high-temperature composting method. Background Art

[0002] With the expansion and intensification of livestock farming, the amount of livestock manure and wastewater generated is increasing rapidly, posing a critical environmental challenge in current agricultural production. Furthermore, to promote green, low-carbon agriculture globally, measures are being implemented worldwide to ban straw burning, reduce air pollution, and lower greenhouse gas emissions. Aerobic composting is a key approach to resource utilization of livestock manure and straw. However, improper temperature control during the composting process can prevent the complete destruction or degradation of pathogens, posing potential risks to the environment and human health.

[0003] While traditional composting methods can achieve mature straw or manure, they suffer from slow temperature rise and short high-temperature durations, which can result in incomplete treatment of some pathogens. Furthermore, as the temperature rises, gaseous substances in the material are significantly lost, resulting in a low degree of humification and poor fertilizer efficiency. Furthermore, conventional fermentation agents typically have a short survival period at high temperatures, and frequent turning of the compost after rising temperatures leads to significant organic matter loss. Furthermore, frequent turning of large compost piles significantly increases capital costs. Therefore, controlling the internal factors of the composting process is particularly important.

[0004] In summary, the existing composting methods and the composting agents used have poor stability during the high temperature period of composting, a short duration of high temperature, insufficient high temperature resistance of the microbial agents, and a short survival cycle, resulting in poor fertilizer efficiency, large organic matter loss, and poor quality of the organic fertilizer products produced by composting and fermentation.

[0005] Therefore, how to provide an organic fertilizer product that has good high temperature resistance, long survival cycle, and can fully ferment and decompose straw and feces materials in large-scale composting processes, and obtain an organic fertilizer product with high organic matter content, good product quality, and significant fertilizer effect, has become a technical problem that needs to be solved urgently. Summary of the Invention

[0006] The present invention is intended to address the above-mentioned technical problems, thereby providing a composite bacterial agent for composting large-scale livestock and poultry manure and straw, and a high-temperature composting method. The technical purpose of the present invention is to solve the problem that existing fermentation bacterial agents have a short survival period during the composting fermentation process and poor high-temperature resistance, resulting in a short high-temperature duration during the fermentation process, an inability to fully decompose the organic raw materials, and a poor quality of the resulting organic fertilizer with low fertilizer efficiency.

[0007] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0008] The present invention first provides a composite microbial agent for composting large-scale livestock and poultry manure and straw. The composite microbial agent comprises: Bacillus licheniformis, with a live bacterial count of ≥100 million / mL and a strain number of SCAU1602; Arthrobacter terrestris, with a live bacterial count of ≥100 million / mL and a strain number of CGMCC No.1.15654; ​​Bacillus subtilis, with a strain number of CGMCC No.1570; and Brevibacillus laterosporus, with a strain number of CGMCC No.24130. The bacterial liquids of Bacillus licheniformis and Arthrobacter terrestris are mixed in a volume ratio of 1:1 (to form a liquid microbial agent); the Bacillus subtilis and Brevibacillus laterosporus are mixed in a mass ratio of 1:1 (to form a solid powder); and the four microbial agents are mixed in the following ratio to form a high-temperature microbial agent: Bacillus licheniformis: Arthrobacter terrestris: Bacillus subtilis: Brevibacillus laterosporus = 16L: 1.5kg: 1.5kg: 16L.

[0009] Furthermore, the effective viable counts of the Bacillus subtilis and Brevibacillus laterosporus are both ≥ 500 million / g.

[0010] The second object of the present invention is to provide a method for composting and ripening large livestock and poultry manure and straw, which uses the composite bacterial agent as described above to perform composting, fermentation and ripening.

[0011] Specifically, the method of composting fermentation using the composite bacterial agent of the present invention comprises the following steps:

[0012] (1) After air-drying and crushing the straw, the straw is fully mixed with feces to form a pile material, and water is added to the pile material to obtain a viscous material;

[0013] (2) activating the composite bacterial agent, adding a sugar source thereto, and mixing to obtain a suspension containing the composite bacterial agent;

[0014] (3) The suspension is mixed with the viscous material, and aerobic composting and fermentation are carried out under ventilation conditions to obtain the product.

[0015] Furthermore, in step (1), the straw is crushed to a particle size of 1 to 5 cm.

[0016] Furthermore, the straw includes rice straw, peanut vines, wheat straw, corn straw or sorghum straw.

[0017] Furthermore, in step (1), the dry weight ratio of feces to straw is controlled to be 2:1, and the moisture content of the viscous material is controlled to be 60% to 65%.

[0018] Furthermore, in step (2), the sugar source is honey, preferably brown sugar.

[0019] Furthermore, the added amount of the composite bacterial agent accounts for 9‰ of the total dry weight of the pile material.

[0020] Furthermore, in the step (3), ventilation is performed using ventilation equipment, which is composed of three bent PVC pipes and is completely symmetrical on both sides of the central axis (Ⅰ-Ⅰ). The ventilation equipment is connected at the vent, an elbow connection is provided at the two-pipe bending connection, a straight four-way connection is provided at the four-pipe bending connection, and the air outlet directly contacts the pile. The ventilation equipment is externally connected to a gas collection and processing device, and the ventilation port rate and the air outlet rate of the ventilation equipment can be freely set.

[0021] Furthermore, during the composting fermentation in step (3), the oxygen concentration inside the pile is controlled to be not less than 8%. When the temperature inside the pile reaches 55°C, ventilation is performed once every 4 to 6 hours, each ventilation time is 15 to 20 minutes, and the ventilation volume is 0.05 to 0.1 m 3 min -1 When the temperature reaches 60℃, ventilation time is 2h and ventilation volume is 0.1~0.25m 3 min -1 ; Turn the pile every 8 to 12 days, and keep the moisture content of the turned material at 63% to 65%; when the temperature is higher than 65℃, turn the pile directly.

[0022] It is particularly noted that the present invention can mix the suspension containing the bacterial flora with the viscous material in batches, and the suspension is evenly divided into three parts. The pile is divided into three layers from bottom to top, namely, lower, middle and upper layers, which are evenly sprinkled one by one to ensure that there is sufficient material supply during the high temperature period of the microorganisms, thereby extending the high temperature period.

[0023] In addition, when laying ventilation equipment, the present invention can reach 1 / 3 of the bottom of the pile to reduce the number of times the pile is turned over, reduce costs, and be used for continuous control of high temperature and reduce the volatilization of organic matter.

[0024] The beneficial effects of the present invention are as follows:

[0025] (1) The present invention provides a high-temperature composite bacterial agent suitable for large-scale composting fermentation, which has the advantages of good high-temperature resistance, long survival period during the composting process, and the ability to fully decompose the fermented materials;

[0026] (2) The fermentation method of the present invention can obtain a long-term continuous high-temperature environment in the pile, so that the pile materials can be fully fermented and decomposed. At the same time, combined with the ventilation equipment of the present invention, it can well control the stability of the high-temperature environment during the fermentation process of the pile, thereby improving the quality of organic fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of the ventilation equipment of the present invention;

[0028] Figure 2This is a characteristic diagram of temperature changes of different composts in Example 1 of the present invention;

[0029] Figure 3 This is a completed drawing of the pile body according to Example 1 of the present invention;

[0030] Figure 4 This is a characteristic diagram of temperature changes of different composts in Example 2 of the present invention;

[0031] Figure 5 This is a completed drawing of the pile body according to Example 2 of the present invention;

[0032] Figure 6 This is a characteristic diagram of temperature changes of different composts in Example 3 of the present invention;

[0033] Figure 7 This is a completed drawing of the pile body according to embodiment 3 of the present invention.

[0034] Among them, Ⅰ-Ⅰ, equipment center axis; A, vent rate; B, outlet rate; 1, vent; 2, two-pipe bending connection; 3, outlet; 4, four-pipe bending connection; 5, external gas collection and processing device. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the embodiments and accompanying drawings. It is necessary to point out that the following embodiments are only intended to explain and illustrate the present invention and are not intended to limit the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content still fall within the scope of protection of the present invention.

[0036] The composite bacterial agent provided by the present invention is composed of the following bacterial species: Starter A, effective bacterial species name: thermophilic Bacillus licheniformis, bacterial liquid viable count ≥ 100 million / mL, strain number SCAU1602. Starter B, effective bacterial species name: Bacillus subtilis, strain number CGMCC No. 1570; Brevibacillus laterosporus, strain number CGMCC No. 24130, effective viable count ≥ 500 million / g, the above two bacterial powders are mixed in a mass ratio of 1:1. Starter C, Arthrobacter humicola, bacterial liquid viable count ≥ 100 million / mL, strain number CGMCC No. 1.15654. The above composite bacterial agents are mixed in a ratio of 16L: 3kg: 16L to form a thermophilic bacterial agent.

[0037] The present invention provides a ventilation device for stabilizing temperature in a composting process (see Figure 1), the equipment comprises three bent pipes from top to bottom, all of which are made of PVC pipes and are completely symmetrical on both sides of the central axis Ⅰ-Ⅰ, and are connected on both sides to form a ventilation duct, the vent 1 is connected to the ventilation equipment, the two-tube bent connection 2 is provided with an elbow connection, and the four-tube bent connection 4 is provided with a straight four-way connection, the air outlet 3 is in direct contact with the pile, the ventilation equipment is externally connected to a gas collection and processing device 5, and the equipment vent rate A and the air outlet rate B can be freely set.

[0038] The present invention provides a composting method for mixed decomposition of livestock and poultry manure and straw, comprising the following steps:

[0039] (1) After air-drying the straw, it is physically crushed and fully mixed with feces, and appropriate water is added to obtain a viscous substance;

[0040] (2) activating the thermophilic microbial flora, transferring the flora from the storage tank to the fermentation tank, adding a sugar source, and mixing to obtain a suspension containing the flora;

[0041] (3) Mix the suspension with the viscous material, install ventilation equipment, and then carry out routine aerobic composting work.

[0042] There is no specific order for steps (1) and (2) above, and it depends on the workload of the pile. It is recommended that the bacterial colony be completed 2 hours before step (3).

[0043] In the present invention, the aerobic composting method for the mixed decomposition of livestock and poultry manure and straw is preferably a method in which a suspension after activation of a high-temperature bacterial agent is evenly sprinkled on the viscous material mixed with manure and straw, and the moisture content of the compost material is regulated to perform high-temperature aerobic composting. The straw in step (1) is preferably corn and / or sorghum and / or distiller's grains, and its type is not limited, and conventional crop waste can be used, such as rice straw, peanut vines, wheat straw, etc. The straw is physically crushed to a particle size of 1 to 5 cm, the dry weight ratio of manure and straw before mixing is 2:1, the carbon-nitrogen ratio of the material is adjusted to 25:1, and when replenishing water, the water source can be livestock and poultry sewage, and the moisture content of the final mixed viscous material is adjusted to 60% to 65%.

[0044] In the present invention, the materials are piled into strips with a height of 1.2 to 2.5 m and a width of 4 to 6 m. The length of the pile depends on the volume of the compost. The suspension containing the bacterial flora in step 3) is evenly divided into three parts, and the pile is divided into three layers from bottom to top: lower, middle and upper. A ventilation duct is laid at 1 / 3 of the bottom of the pile, and the suspension is then mixed with the viscous material in layers and batches, and sprinkled evenly one by one. The ventilation of the pile is determined by the activity environment of the microorganisms inside the pile, and the internal oxygen concentration should not be lower than 8%. In the early stage of composting, the material reaction is insufficient. When the temperature does not rise to 55°C within 3 days, ventilation is carried out for 15 to 20 minutes at intervals of 4 to 6 hours, and the ventilation volume is 0.05 to 0.1 m 3 min -1(Based on per cubic meter of material); when the temperature reaches 60℃, ventilate for 2 hours with a ventilation volume of 0.1-0.25m 3 min -1 (Based on per cubic meter of material), turn the pile every 8 to 12 days, and maintain the moisture content of the turned material at 63% to 65%; when the temperature is higher than 65°C, turn the pile as soon as possible.

[0045] The present invention will be further explained below in conjunction with specific embodiments. Unless otherwise specified, the experimental methods used in the following specific examples are all conventional methods. The operations involved in the following specific examples, where conditions are not specified, were performed under conventional conditions or manufacturer's recommended conditions. Raw materials used, where the manufacturer and specifications are not specified, can be obtained from commercially available conventional products.

[0046] Example 1

[0047] The livestock and poultry manure was a mixture of cow dung and sheep manure at a dry weight ratio of 9:1, while the straw was a mixture of sorghum straw and distiller's grains at a dry weight ratio of 8:2. The straw was crushed into pellets approximately 5 cm in diameter and mixed with the manure, with a manure-to-straw dry weight ratio of 2:1. The carbon-nitrogen ratio of the material was adjusted to 25:1. The moisture content of the mixed viscous material was adjusted to 60%, and the water source was the pig manure pond on the farm. A suspension activated by a high-temperature bacterial agent was added to the viscous material at a rate of 9‰ of the dry weight of the pile material. Three fermentation piles were finally formed, with the following specifications: Pile 1: 10.5m (length) × 5.0m (width) × 2.4m (height), Pile 2: 12.5m (length) × 6.0m (width) × 1.7m (height), and Pile 3: 11.8m (length) × 5.5m (width) × 2.0m (height). The temperature of the composting pile rises slowly in the early stage. The temperature of the pile rises to 55℃ within 3 days. At this time, the ventilation interval is 4 hours, 15 minutes, and the ventilation volume is 0.05m 3 min -1 (Based on per cubic meter of material), intermittent ventilation is used to ensure that the oxygen concentration inside the pile is above 8%; when the pile temperature reaches 60℃, ventilation is carried out for 2 hours with a ventilation volume of 0.1m 3 min -1 (Based on per cubic meter of material), the pile should be turned over every 8 days, and the moisture content of the turned material should be maintained at 63%.

[0048] Example 2

[0049] The livestock and poultry manure is made of pig manure, and the straw is made of corn and sorghum straw mixed at a dry weight ratio of 6:4. The straw is crushed into particles of about 3 cm and mixed with the manure, and the dry weight ratio of manure to straw is 2:1. The carbon-nitrogen ratio of the material is adjusted to 25:1. The moisture content of the viscous material after mixing is adjusted to 60%, and the water source is based on the principle of proximity. The suspension activated by the high-temperature bacterial agent is added to the viscous material at a rate of 9‰ of the dry weight of the pile material, and finally piled into a fermentation pile with a specification of 38.0m (length) × 6.0m (width) × 2.2m (height). When the pile temperature reaches 60°C, ventilate for 2 hours with a ventilation volume of 0.25m 3 min -1 (Based on per cubic meter of material), intermittent ventilation is used to ensure that the oxygen concentration inside the pile is above 8%. The pile is turned over every 12 days, and the moisture content of the turned material is maintained at 65%.

[0050] Example 3

[0051] The livestock and poultry manure is made of pig manure and chicken manure mixed at a dry weight ratio of 9:1, and the straw is made of corn straw. The straw is crushed into particles of about 3 cm and mixed with the manure, and the dry weight ratio of manure to straw is 2:1. The carbon-nitrogen ratio of the material is adjusted to 25:1. The moisture content of the mixed viscous material is adjusted to 60%, and the water source is based on the principle of proximity. The suspension activated by the high-temperature bacterial agent is added to the viscous material at a ratio of 9‰ of the dry weight of the pile material, and finally piled into a fermentation pile with a specification of 37.0m (length) × 5.5m (width) × 1.5m (height). When the pile temperature reaches 62°C, ventilate for 2 hours with a ventilation volume of 0.15m 3 min -1 Use intermittent ventilation to maintain an oxygen concentration above 8% (based on per cubic meter of material). Turn the pile every 10 days, maintaining a moisture content of 64%. Turn the pile as soon as possible when the temperature exceeds 65°C.

[0052] Comparative Examples 1-6: Examination of compound bacterial agent formula

[0053] Except for the different mixing ratios of the high-temperature bacterial agents (a total of 6 groups with different ratios were set, see Comparative Examples 1-6), the other composting parameters were the same as those in Example 1, and conventional operations were performed in accordance with the NYT3442-2019 technical specifications, see Table 1.

[0054] Table 1 Different mixing ratios of high temperature bacterial agents

[0055]

[0056] Comparative Examples 7-10: Examination of the number of ventilation equipment pipes

[0057] The ventilation equipment was examined, and the traditional ventilation method (natural turning and ventilation, without setting ventilation ducts in the compost body) was used as a control. Except for the number of ventilation ducts, the other composting parameters were consistent with those in Example 1, and conventional operations were performed in accordance with the NYT3442-2019 technical specifications, as shown in Table 2.

[0058] Table 2 Treatment of different ventilation equipment

[0059]

[0060] Experimental Example 1

[0061] The products obtained after composting of Example 1-3 were inspected (see Figure 2-7 ), the acceptance indicators are implemented in accordance with the corresponding national regulations, and the final acceptance results of the embodiment are as follows Table 3:

[0062] Table 3 Compost product acceptance results

[0063]

[0064] As can be seen from Table 3, in Example 1, the results at the end of composting showed that the compost quality was 38% higher than the national standard in terms of organic matter growth rate, 83.5% higher in terms of total nutrients (N+P2O5+K2O), 85.0% higher in terms of seed germination index (GI), 47% lower in terms of fecal coliform count, and 98% higher in terms of ascaris egg mortality. Figure 2 The composting time is 60 days, the temperature rises to 55℃ within 3 days, and the longest high temperature period above 60℃ can reach 31 days. By timely monitoring and adjusting the temperature through ventilation control, the high temperature duration can be extended, which is conducive to the decomposition of organic matter in the pile.

[0065] In Example 2, the results at the end of composting showed that the compost quality was 84.75% higher than the national standard in terms of total nutrient (N+P2O5+K2O), 81.9% higher in germination index (GI), 57% lower in fecal coliform count, and 98% higher in Ascaris egg mortality. Figure 4 The composting days are 59 days, the temperature rises to 55℃ within 3 days, the high temperature above 60℃ can last up to 30 days, and the highest temperature can reach 69℃.

[0066] In Example 3, the results at the end of composting showed that the compost quality was 73.5% higher than the national standard in terms of total nutrient (N+P2O5+K2O), 82.6% higher in germination index (GI), 36% lower in fecal coliform count, and 97% higher in Ascaris egg mortality. Figure 6 The composting days are 56 days, the temperature rises to 55℃ within 3 days, and the high temperature above 60℃ can last up to 30 days.

[0067] Experimental Example 2

[0068] The heating time and the duration of high temperature during the composting process (based on the temperature in the compost reaching 60° C. or above) of the methods of Examples 1-3 and Comparative Examples 1-6 were recorded, and the organic matter content and total nutrient content of the products obtained after composting were statistically analyzed. The results are shown in Table 4 below:

[0069] Table 4 Comparison of organic matter and high temperature duration of products obtained by the methods of the embodiments and comparative examples

[0070]

[0071] By comparison with the comparative example, it can be seen that the microbial strain ratio of the embodiment of the present invention has the best composting effect, the high temperature duration period has been effectively extended, the longest can reach 31 days, and the initial temperature increase efficiency has been significantly improved, and the temperature can be raised to above 60°C in 3 days at the fastest. In particular, the preservation of organic matter and total nutrients is particularly outstanding, with an average organic matter content of 40.57% and a total nutrient content of 7.22%, thereby achieving a high-quality composting effect of the manure straw mixture.

[0072] However, in the method of the comparative example, the maximum temperature during the composting process fluctuates greatly, the heating time is long, and the high temperature duration is short. The organic matter content and total nutrient content of the obtained product are insufficient, and the product quality is poor.

[0073] Experimental Example 3

[0074] The heating time and the duration of high temperature (above 60° C.) during the composting process of the methods of Example 1 and Comparative Examples 7-10 were recorded. The results are shown in Table 5 below:

[0075] Table 5 Comparison of high temperature duration and fastest temperature rise treated by different ventilation equipment

[0076]

[0077] By comparing with the comparative examples of different ventilation equipment, it is found that the ventilation equipment of the embodiment of the present invention significantly improves the duration of the high temperature period, which can reach an average of more than 30 days, and can shorten the number of days of initial temperature rise to within 5 days. It can be seen that the simple and efficient ventilation facility treatment combined with the design of the present invention can better assist in maintaining the continuous stability of the entire high temperature period.

[0078] Although the above embodiments provide a detailed description of the present invention to enable those skilled in the art to implement or use the present invention, they are merely some embodiments of the present invention, not all of them. Other embodiments that do not depart from the principles of the present invention are also within the scope of protection of the present invention.

Claims

1. A composite bacterial agent for composting large livestock and poultry manure and straw, characterized in that: The composite bacterial agent includes: Bacillus licheniformis, with a live bacterial count of ≥100 million / mL and a strain number of SCAU1602; Bacillus terrestris, with a live bacterial count of ≥100 million / mL and a strain number of CGMCC No.1.15654; ​​Bacillus subtilis, with a strain number of CGMCC No.1570; and Brevibacillus laterosporus, with a strain number of CGMCC No.24130. The bacterial liquids of Bacillus licheniformis and Bacillus terrestris are mixed in a volume ratio of 1:1; the Bacillus subtilis and Brevibacillus laterosporus are mixed in a mass ratio of 1:1; and the four bacterial agents are mixed in the following ratio to form a high-temperature bacterial agent: Bacillus licheniformis: Bacillus terrestris: Bacillus subtilis: Brevibacillus laterosporus = 16L: 1.5kg: 1.5kg: 16L.

2. The composite microbial agent for composting large livestock and poultry excrement and straw according to claim 1, characterized in that: The effective viable bacterial counts of the Bacillus subtilis and Brevibacillus laterosporus are both ≥500 million / g.

3. A method for composting large livestock and poultry manure and straw, characterized in that: The composite bacterial agent according to claim 1 or 2 is used for compost fermentation and decomposition.

4. The method according to claim 3, characterized in that The following steps are involved: (1) After air-drying and crushing the straw, the straw is fully mixed with feces to form a pile material, and water is added to the pile material to obtain a viscous material; (2) activating the composite bacterial agent, adding a sugar source thereto, and mixing to obtain a suspension containing the composite bacterial agent; (3) The suspension is mixed with the viscous material, and aerobic composting and fermentation are carried out under ventilation conditions to obtain the product.

5. The method according to claim 4, characterized in that In the step (1), the straw is crushed to a particle size of 1 to 5 cm; preferably, the straw includes rice straw, peanut vines, wheat straw, corn straw or sorghum straw.

6. The method according to claim 4, characterized in that In the step (1), the dry weight ratio of feces to straw is controlled to be 2:1, and the moisture content of the viscous material is controlled to be 60% to 65%.

7. The method according to claim 4, characterized in that In step (2), the sugar source is molasses, preferably brown sugar.

8. The method according to claim 4, characterized in that The added amount of the composite bacterial agent accounts for 9‰ of the total dry weight of the pile material.

9. The method according to claim 4, characterized in that In the step (3), ventilation is performed using a ventilation device, which is composed of three bent PVC pipes and is completely symmetrical along both sides of the central axis (Ⅰ-Ⅰ). By connecting the ventilation device at the ventilation port (1), the two ends of the three PVC pipes are connected by bending, an elbow connection is provided at the two-pipe bending connection (2), and a straight four-way connection is provided at the four-pipe bending connection (4). The ventilation device is in direct contact with the pile at the air outlet (3), and the ventilation device is externally connected to a gas collection and processing device. The ventilation port rate and the air outlet rate of the ventilation device can be freely set.

10. The method according to claim 5, characterized in that During the composting fermentation in step (3), the oxygen concentration inside the pile is controlled to be not less than 8%. When the temperature inside the pile reaches 55°C, ventilation is performed once every 4 to 6 hours, with each ventilation time of 15 to 20 minutes and a ventilation volume of 0.05 to 0.1 m 3 min -1 When the temperature reaches 60℃, ventilation time is 2h and ventilation volume is 0.1~0.25m 3 min -1 ; Turn the pile every 8 to 12 days, and keep the moisture content of the turned material at 63% to 65%; when the temperature is higher than 65℃, turn the pile directly.

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