Livestock and poultry solid manure aerobic composting process capable of reducing generation of nitrous oxide

Abstract

The invention relates to a livestock and poultry solid manure aerobic composting process capable of reducing generation of nitrous oxide, and belongs to the technical field of agriculture. The invention provides a livestock and poultry solid manure aerobic composting process for reducing generation of nitrous oxide, which comprises the following steps: mixing livestock and poultry solid manure and auxiliary materials, and adjusting the C / N ratio and the water content to obtain a mixed substrate; adding a nitrifying bacterium agent and a denitrification inhibitor into the mixed matrix, mixing to form a pile body, covering the pile body with a molecular film, arranging an aeration device at the bottom of the pile body for aerobic composting, and ending composting when the temperature of the pile body is less than or equal to 40 DEG C, the water content is less than or equal to 30% and the seed germination index is more than or equal to 70%. Aerobic composting of livestock and poultry manure is optimized through molecular film covering and coupling nitrification and denitrification treatment, the nitrite reduction effect is reduced through a denitrification inhibitor, conversion of nitrite to nitrate is enhanced through nitrifying bacteria, finally, N2O emission is reduced, nitrogen loss is reduced, the humification effect is enhanced, and humus stability is improved.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to an aerobic composting process for livestock and poultry solid manure that reduces nitrous oxide production. Background Technology

[0002] Livestock and poultry manure, especially pig manure with high protein content, easily releases nitrogen in gaseous forms such as ammonia and nitrous oxide during aerobic fermentation due to pH increases caused by protein degradation and the emergence of anaerobic zones within the compost pile. This leads to environmental problems such as odor pollution from ammonia release and exacerbates the greenhouse effect through nitrous oxide formation. Furthermore, it results in low nutrient content and poor fertilizer efficiency in the finished organic fertilizer. Based on the nitrogen cycle mechanism, the loss of N2O and N2 nitrogen in aerobic composting mainly originates from denitrification. The warming effect of N2O was 273 times that of CO2 in the Sixth IPCC Assessment Report (IPCC 2022). To reduce nitrous oxide emissions from agricultural solid waste treatment processes and ensure nutrient preservation in organic fertilizers, the control of N2O production should focus on regulating nitrification and denitrification reactions.

[0003] Most existing aerobic composting technologies for livestock and poultry solid manure emission reduction rely on physical adsorption or chemical treatment. Physical adsorption often results in re-release after the sites are fully occupied, while chemical treatment can easily lead to secondary pollution. Furthermore, existing technologies struggle to ensure smooth aerobic fermentation while reducing emissions, sacrificing some of the humification reaction and lowering the quality of the finished organic fertilizer.

[0004] Therefore, in the aerobic composting process of livestock and poultry solid manure, how to reduce N2O production while ensuring sufficient humification is a current technical and technological challenge. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an aerobic composting process for livestock and poultry solid manure that reduces nitrous oxide production.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an aerobic composting process for reducing nitrous oxide production, comprising the following steps: (1) Mix livestock and poultry solid manure and auxiliary materials and adjust the C / N ratio and moisture content to obtain a mixed substrate; (2) Add nitrifying bacteria and denitrification inhibitor to the mixed substrate obtained in step (1) to form an aerobic fermentation pile. Cover the aerobic fermentation pile with a molecular membrane and set up an aeration device at the bottom of the aerobic fermentation pile for aerobic composting. When the temperature of the aerobic fermentation pile is ≤40℃, the moisture content is ≤30%, and the seed germination index is ≥70%, the composting is ended.

[0007] This invention optimizes aerobic composting of livestock and poultry manure by coupling nitrification and denitrification through molecular membrane covering, reduces nitrite reduction by using denitrification inhibitors, and enhances the conversion of nitrite to nitrate through nitrifying bacteria, ultimately reducing N2O emissions, decreasing nitrogen loss, enhancing humification, and improving the stability of humus.

[0008] In a preferred embodiment of the process described in this invention, in step (1), the C / N ratio of the mixed matrix is ​​C:N = (16-30):1, and the moisture content is 55-63%. In this invention, the C / N ratio refers to the absolute mass ratio of total carbon (C) to total nitrogen (N) in the material.

[0009] As a preferred embodiment of the process described in this invention, in step (1), the C / N ratio of the mixed matrix is ​​C:N = (18-28):1, and the moisture content is 58-62%.

[0010] In a preferred embodiment of the process described in this invention, in step (1), the C / N ratio of the mixed matrix is ​​C:N = (20-25):1, and the moisture content is 59-60%. The C / N ratio of the mixed matrix can also be at least one of 21:1, 22:1, 23:1 and 24:1 (C:N), and the moisture content is 60%.

[0011] In a preferred embodiment of the process described in this invention, in step (1), the C / N ratio of the auxiliary material is C:N = (25-30):1, and the moisture content of the auxiliary material is 20-40%. As a preferred embodiment of the process described in this invention, in step (1), the auxiliary materials include at least one of mushroom residue, rice husk, straw, sawdust and wheat straw.

[0012] As a preferred embodiment of the process described in this invention, in step (1), the particle diameter of the livestock and poultry manure is 3-5 cm.

[0013] In a preferred embodiment of the process described in this invention, in step (1), the particle diameter of the auxiliary material is 3-5 cm.

[0014] As a preferred embodiment of the process described in this invention, in step (2), the nitrifying agent includes oxidative nitrification promoting bacteria.

[0015] As a preferred embodiment of the process described in this invention, in step (2), the oxidative nitrification promoting bacteria include at least one of ammonia oxidizing bacteria, nitrite oxidizing bacteria, ammonia oxidizing archaea, and complete ammonia oxidizing bacteria.

[0016] As a preferred embodiment of the process described in this invention, in step (2), the amount of nitrifying bacteria agent is 0.3-0.7g of nitrifying bacteria agent per 100g dry weight of mixed matrix.

[0017] As a preferred embodiment of the process described in this invention, in step (2), the amount of nitrifying agent is 0.5g of nitrifying agent per 100g dry weight of mixed matrix.

[0018] As a preferred embodiment of the process described in this invention, in step (2), the denitrification inhibitor includes sodium diethyldithiocarbamate.

[0019] Copper-type nitrite reductases (Cu-NiRs) are nitrite reductases, trimeric proteins composed of three identical subunits, each containing two types of copper active sites. A key step in the electron transfer process of Cu-NiRs is the electron transfer from the T1-Cu site to the T2-Cu site. Specifically, the T1-Cu site receives an electron from an external source and then transfers it to the T2-Cu catalytic site, where it accepts the electron and reduces nitrite. This crucial step achieves efficient electron transfer and nitrite reduction. Based on this, the inventors hypothesized that reducing electron binding sites could inhibit the activity of Cu-NiRs. Taking advantage of this characteristic, this invention selects sodium diethyldithiocarbamate (DDTC, CAS No. 148-18-5) as a denitrification inhibitor for aerobic composting. Under the expanded oxidative environment of the molecular membrane, the carbon-sulfur groups of DDTC complex with the Cu catalytic sites of Cu-NiRs, preventing the T1-Cu and T2-Cu sites from accepting electrons, thus inhibiting the activity of Cu-NiRs and reducing nitrite reduction. Simultaneously, the nitrifying bacteria added in this invention enhance the conversion of nitrite to nitrate, reducing the formation of N2O precursors and lowering N2O production, effectively improving the poor nitrogen retention during aerobic composting. Furthermore, the enhancing effect of nitrifying bacteria on the oxidation reaction also strengthens the humification of the compost pile, improving the stability of the humus after aerobic composting.

[0020] As a preferred embodiment of the process described in this invention, in step (2), the amount of denitrification inhibitor used is 0.3-0.7g of denitrification inhibitor per 100g dry weight of mixed matrix.

[0021] As a preferred embodiment of the process described in this invention, in step (2), the amount of the denitrification inhibitor is 0.5g of denitrification inhibitor per 100g dry weight of mixed matrix.

[0022] As a preferred embodiment of the process described in this invention, in step (2), the height-to-width ratio of the aerobic fermentation pile is height:width = 3:(4-5).

[0023] In a preferred embodiment of the process described in this invention, in step (2), the parameters of the molecular membrane are as follows: air permeability 1.8-2.5 mm / s 200 Pa, moisture permeability 7000-7200 g / (m²). 2 •h), wet resistance 9-10m 2 • Pa / w, hydrostatic pressure 140-150 kPa. Molecular membranes within this parameter range have good air permeability, which can effectively maintain the moisture of the substrate during composting, making it difficult for N2O precursors generated during composting to escape, enhancing the nitrification effect of nitrifying bacteria, reducing N2O emissions from multiple aspects while maintaining excellent composting effect.

[0024] As a preferred embodiment of the process described in this invention, in step (2), the parameters of the molecular membrane are as follows: air permeability 2.16 mm / s 200 Pa, moisture permeability 7170 g / (m²). 2 •h), wet resistance 9.55m 2 ·Pa / w, hydrostatic pressure 144.16kPa.

[0025] As a preferred embodiment of the process described in this invention, in step (2), the aeration device includes an aeration pipe, a blower, and a pipe arrangement.

[0026] As a preferred embodiment of the process described in this invention, in step (2), the pipe laying includes fixed pipe laying and / or movable pipe laying.

[0027] As a preferred embodiment of the process described in this invention, in step (2), the aeration pipe in the aeration device is connected to one end of the blower, and the other end of the blower is connected to the distribution pipe.

[0028] As a preferred embodiment of the process described in this invention, in step (2), the aeration rate in the aerobic composting is 0.2-0.3 L / min per kilogram of mixed substrate.

[0029] Secondly, the present invention provides the application of the above-mentioned process in composting to reduce nitrous oxide emissions.

[0030] Thirdly, the present invention provides the application of the above-mentioned process in improving the humification of compost products and / or improving seed germination rate.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention optimizes aerobic composting of livestock and poultry manure by coupling nitrification and denitrification through molecular membrane covering, reduces nitrite reduction by using denitrification inhibitors, and strengthens the conversion of nitrite to nitrate through nitrifying bacteria, thereby reducing N2O emissions, reducing nitrogen loss, enhancing humification, and improving the stability of humus.

[0032] (2) In this invention, sodium diethyldithiocarbamate (DDTC) is selected as an inhibitor of denitrification in aerobic composting. Under the expansion of the molecular membrane oxidation environment domain, DDTC complexes with Cu at the enzyme catalytic site to inhibit the activity of nitrite reductase and reduce nitrite reduction. At the same time, the addition of nitrifying bacteria can enhance the conversion of nitrite to nitrate, reduce N2O emissions, enhance humification, and improve the quality of compost products. Attached Figure Description

[0033] Figure 1 This is a graph showing the dynamic changes in temperature and moisture content during the aerobic composting process in the experimental examples of this invention. Figure 2 This is a graph showing the dynamic changes in nitrogen content during the aerobic composting process in the experimental examples of this invention. Figure 3 This is a graph showing the dynamic changes in N2O content during the aerobic composting process in the experimental examples of this invention. Figure 4 This is a graph showing the dynamic changes in the content of humic acid (HA) and fulvic acid (FA) during the aerobic composting process in the experimental examples of this invention. Figure 5 This is a dynamic change graph of the humification ratio (HR) and humification index (HI) during the aerobic composting process in the experimental examples of this invention. Figure 6 This is a dynamic change graph of the seed germination index (GI) during the aerobic composting process in the experimental examples of this invention. Detailed Implementation

[0034] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] In this invention, the C / N ratio refers to the ratio of the absolute mass of total carbon (C) to total nitrogen (N) in the material.

[0036] Unless otherwise specified, all other materials and reagents used in the experiments are commercially available.

[0037] The determination of moisture content, seed germination index, and total organic matter mentioned in the following experimental examples was carried out according to the industry standard "Organic Fertilizer" (NY / T525-2021); NH4 + -N, NO3 --N was determined according to the national standard GB / T 42487-2023; N2O was collected using a static box method and then detected by GC-MS; Humic acid (HA) and fulvic acid (FA) were determined according to the industry standard NY / T 1867-2010. Humic index (HI) = HA / FA × 100%; Humic ratio (HR) = (HA + FA) / TOC × 100%; N2O emission reduction rate = (cumulative N2O emission of control group - cumulative N2O emission of treatment group) / cumulative N2O emission of control group; Nitrogen preservation effect = (total nitrogen at the end of composting - total nitrogen of compost matrix) / total nitrogen of compost matrix; Humic improvement = (HI at the end of composting - HI at the beginning of composting) / HI at the beginning of composting.

[0038] The molecular membrane parameters used are as follows: air permeability 2.16 mm / s 200 Pa, moisture permeability 7170 g / (m³). 2 •h), wet resistance 9.55m 2 • Pa / w, hydrostatic pressure 144.16 kPa, breaking strength (warp) 4000 N, breaking strength (weft) 2000 N, tearing strength (warp) 820 N, tearing strength (weft) 340 N, peel strength (warp) 2.7 N / 25 mm, peel strength (weft) 4.1 N / 25 mm, dimensional change in water immersion (warp) -0.7%, dimensional change in water immersion (weft) -1.0%, light fastness > 4, wash fastness 4-5, rubbing fastness 4-5, acid stain fastness 4-5.

[0039] The type of livestock and poultry manure described in this invention is not specifically limited, and can be selected from chicken manure, pig manure, cow manure, etc. The livestock and poultry manure used in the following experimental examples is pig manure (C / N ratio is C:N=(10-15):1), and the particle diameter is 3-5cm.

[0040] The auxiliary material described in this invention is a high C / N ratio and low moisture content material, which can be selected from mushroom residue, rice husk, straw, sawdust and wheat straw, etc. The auxiliary material used in the following experimental examples is mushroom residue (C / N ratio is C:N=(25-30):1, moisture content is 20-40%), and the particle diameter is 3-5cm.

[0041] The denitrification inhibitor used in the following experimental examples is sodium diethyldithiocarbamate (DDTC, CAS No. 148-18-5).

[0042] The nitrifying bacteria agent described in this invention can be commercially available or homemade, containing microorganisms capable of nitrification. In the following experimental examples, the nitrifying bacteria agent used was homemade by the inventor and includes: aerobic dissimilar nitrate-producing bacteria Bacillus licheniformis (… Bacillus licheniformis ), Lactococcus spp. (ammonia-assimilating bacteria) Lactococcussp.) and Pseudomonas bariairis (sp.) Pseudomonas balearica The concentration ratio of Bacillus licheniformis, Lactococcus spp., and Pseudomonas bariairis is Bacillus licheniformis: Lactococcus spp.: Pseudomonas bariairis = 109.9:1.15:1, wherein the concentration of Pseudomonas bariairis is 1×10⁻⁶. 7 CFU / g.

[0043] Experimental Example To evaluate the effects of composting with mulched nitrifying bacteria and denitrification inhibitors, pig manure and mushroom residue were mixed and composted using the following specific scheme: The experiment was divided into five groups: ① no membrane covering, no nitrifying bacteria or denitrification inhibitor added (CK-AC); ② membrane covering, no nitrifying bacteria or denitrification inhibitor added (T1-MCAC); ③ membrane covering coupled with nitrifying bacteria (T2-NB); ④ membrane covering coupled with denitrification inhibitor (T3-DDTC); ⑤ membrane covering coupled with nitrifying bacteria and denitrification inhibitor (T4-NB+DDTC). Sodium diethyldithiocarbamate (DDTC) was used as the denitrification inhibitor.

[0044] Taking T4-NB+DDTC as an example, the specific operation is as follows: S1. Mix pig manure and mushroom residue, and adjust the amount of mushroom residue to a C / N ratio of C:N=22:1 and a moisture content of 60% for the mixed substrate, while keeping the amount of pig manure fixed. S2. Add 0.5g of nitrifying bacteria agent and 0.5g of DDTC to the mixed substrate obtained in step S1 according to the ratio of 100g dry weight. Mix evenly to form an aerobic fermentation pile with a height-to-width ratio of 3:4 (height:width) (hereinafter referred to as the pile). Cover the pile with a molecular membrane, and ensure that the edges of the pile are covered and sealed completely. Set an aeration pipe at the bottom of the pile, and connect a blower and a pipe to the outside of the aeration pipe. S3. Mechanical aeration is used to start the composting process, once every 4 hours, with an aeration rate of 0.2-0.3 L / min per kilogram of mixed substrate, for 20 minutes each time. The compost temperature is monitored daily, and samples are taken on days 1, 3, 6, 10, 14, 21, 28, and 38 to measure moisture content, nitrous oxide (N2O), and nitrogen (NH4). + -N, NO3 - The determination of seed germination index, HA, FA, and humification index (HFA = HA / FA) ​​and the results and analysis are as follows: 1. Dynamic changes in temperature and moisture content during aerobic composting, such as... Figure 1As shown, under an average room temperature of 27℃, the compost pile temperature of treatments T1, T2, and T3 rapidly rose to above 60℃ on the second day, while treatment T4 reached above 60℃ on the third day, indicating that the composting entered a high-temperature period. The temperature continued to rise until the ninth day of composting, reaching its maximum. The highest compost pile temperatures for each treatment were 66.8℃, 66.0℃, 67.3℃, and 69.4℃, respectively. Throughout the composting process, the moisture content of the four treatments gradually decreased. At the end of composting, the moisture content of the organic fertilizer in treatments T1, T2, T3, and T4 were 21.1%, 21.1%, 21.5%, and 21.6%, respectively, all meeting the requirements of the "Organic Fertilizer" (NY / T525-2021) standard.

[0045] 2. Dynamic changes in nitrogen content during aerobic composting process, such as... Figure 2 As shown, NO3 in each treatment - The NO3- content generally shows a gradual increasing trend. (The text abruptly shifts to a different topic:) T3 and T4 treatments for NO3-... - -N content was consistently significantly lower than CK, T1, and T2, while T2 treatment resulted in NO3 content significantly lower. - -N content was higher than that of NO3 in other treatments. - -N content. In NH4 + Regarding NH4+ content, the coating treatment significantly reduced NH4+ during high-temperature periods. + The peak NH4+ content was mainly reduced during the high-temperature period and the later stage of high-temperature reaction after the addition of denitrification inhibitor T3. + -N content, while the addition of nitrifying bacteria (T2 and T4 treatments) delayed NH4 content. + The appearance of the -N content peak. In summary, the membrane-coupled nitrification regulation significantly enhanced the nitrification process in the pile, resulting in more NH4+ being released. + -N is converted to NO3 - -N, while membrane-coated denitrification regulation reduces NH4 + -N content peak, increasing NH4 in organic fertilizer + -N content, but at the same time reduced NO3 content. - -N content.

[0046] 3. Dynamic changes in N2O content during aerobic composting process, such as... Figure 3 As shown, N2O emissions were mainly concentrated on days 1-3 of composting, followed by a second peak in N2O emissions for all treatments on days 6-14, indicating that the activity of denitrifying bacteria increased and became dominant during this period. In particular, the CK-AC and T1 treatments consistently showed higher N2O emission rates than other treatments from days 1 to 10. Overall, the molecular membrane-coupled nitrification-denitrification regulation (T4) had a significant N2O reduction effect throughout the entire aerobic fermentation process, with the best reduction effect observed during the warming period.

[0047] 4. Dynamic changes in HA and FA content during aerobic composting process, as follows: Figure 4 As shown, except for the decrease in humic acid (HA) in CK-AC, the HA content of all treatments showed a continuous upward trend during the composting process. By the end of composting, T1, T2, T3, and T4 increased by 20.4%, 42.7%, 25.9%, and 30.5%, respectively. This indicates that both mulching coupled nitrification and denitrification treatments are beneficial in increasing the HA content in organic fertilizer products. The trends in FA content changes among the treatments were basically consistent. During the heating period, the FA content was relatively unstable, being consumed by microorganisms and simultaneously converted to HA through aromatization. Therefore, the FA content generally decreased from day 6 to day 14, and slowly recovered from day 14 until the end of composting. After composting, the FA content of T1, T2, and T3 decreased by 15.18%, 5.97%, and 2.05% compared to the initial levels, respectively, while the FA content of treatment T4 increased by 16.1% after composting.

[0048] 5. The humification ratio (HR) and humification index (HI) of the aerobic composting process are as follows: Figure 5 As shown, except for CK-AC where HR and HI decreased after aerobic fermentation, HR and HI increased in all other treatments. This indicates that the organic matter in the compost forms a more complex humic structure. Among the treatments, HR increased by 3.5%, 13.8%, 11.0%, and 37.1% compared to the first day, respectively, with the molecular membrane coupled nitrification-denitrification controlled composting treatment (T4) showing the greatest increase in humification ratio. The same trend was observed with HI, which increased by 26.3%, 42.0%, 23.4%, and 44.7% in each treatment. Therefore, the molecular membrane coupled nitrification-denitrification controlled composting treatment (T4) showed the best effect in promoting humification.

[0049] 6. The reduction rate was calculated by measuring the gas emission flux of N2O throughout the composting process (Table 1). Compared with the control treatment CK-AC, both membrane-coated treatments reduced N2O emissions. The membrane-coated denitrification control treatment (T3) and the molecular membrane-coated nitrification-denitrification control treatment (T4) achieved N2O reduction efficiencies of 88.7% and 90.5%, respectively. The T4 treatment showed a significant N2O reduction effect, which is presumably due to the effective control of NO3 formation by DDTC under a slightly positive pressure environment. - Denitrification following the N-N transition.

[0050] After the film-coating coupling treatment, the TN content increased at the end compared to the beginning, with increases of 13.1%, 14.9%, 12.8%, and 16.4% for treatments T1, T2, T3, and T4, respectively. Simultaneously, the humification ratio increased to varying degrees compared to the beginning of composting, with increases of 1.54%, 6.38%, 5.08%, and 15.99% for treatments T1, T2, T3, and T4, respectively.

[0051] Table 1. N2O emission reduction rate, nitrogen conservation effect, and degree of humification improvement under different treatments 7. Dynamic changes in seed germination index (GI) during aerobic composting process, as shown in the figure. Figure 6 As shown, at the initial stage of composting, the seed germination index of each treatment was low, with T1, T2, T3, and T4 at 34.6%, 37.1%, 19.9%, and 14.5%, respectively. As composting progressed, the GI continued to increase. By the end of composting, the seed germination indices of T1, T2, T3, and T4 were 105.0%, 100.6%, 105.0%, and 122.0%, respectively, all of which met and far exceeded the composting standards stipulated in "Organic Fertilizer" (NY / T525-2021).

[0052] In summary, the optimal treatment combination is: adding nitrifying bacteria and denitrification inhibitors, covering with a molecular membrane, and then performing aerobic composting.

[0053] Example 2 This embodiment provides an aerobic composting process to reduce nitrous oxide production, including the following steps: S1. Mix pig manure and mushroom residue, and adjust the amount of mushroom residue to a fixed C / N ratio of C:N=22 and a moisture content of 58% for the mixed substrate. S2. Add 0.5g of nitrifying bacteria agent and 0.5g of DDTC to the mixed substrate obtained in step S1 according to the ratio of 100g dry weight. Mix evenly to form an aerobic fermentation pile with a height-to-width ratio of 3:4 (height:width). Cover the aerobic fermentation pile with a molecular membrane. Ensure that the edges of the aerobic fermentation pile are completely covered and sealed. Set an aeration pipe at the bottom of the aerobic fermentation pile. Connect the aeration pipe to a blower and a pipe. S3. Mechanical aeration is used to start composting. It is turned on once every 4 hours, with an aeration rate of 0.2-0.3 L / min per kilogram of mixed substrate, for 20 minutes each time. The temperature of the aerobic fermentation pile is monitored daily. The heating period is 1-3 days, and the high temperature period (pile temperature > 60℃) is 7-12 days. When the temperature is ≤ 40℃, the moisture content is ≤ 30%, and the seed germination index is ≥ 70%, the composting is completed. The composting process does not require turning or adding additional microbial agents.

[0054] Example 3 This embodiment provides an aerobic composting process to reduce nitrous oxide production, including the following steps: S1. Mix pig manure and mushroom residue, and adjust the amount of mushroom residue to a C / N ratio of C:N=16 and a moisture content of 55% for the mixed substrate, while keeping the amount of pig manure fixed. S2. Add 0.3g of nitrifying bacteria agent and 0.3g of DDTC to the mixed substrate obtained in step S1 according to the ratio of 100g dry weight. Mix evenly to form an aerobic fermentation pile with a height-to-width ratio of 3:5 (height:width). Cover the aerobic fermentation pile with a molecular membrane. Ensure that the edges of the aerobic fermentation pile are completely covered and sealed. Set an aeration pipe at the bottom of the aerobic fermentation pile. Connect the aeration pipe to a blower and a pipe. S3. Mechanical aeration is used to start composting. It is turned on once every 4 hours, with an aeration rate of 0.2-0.3 L / min per kilogram of mixed substrate, for 20 minutes each time. The temperature of the aerobic fermentation pile is monitored daily. The heating period is 1-3 days, and the high temperature period (pile temperature > 60℃) is 7-12 days. When the temperature is ≤ 40℃, the moisture content is ≤ 30%, and the seed germination index is ≥ 70%, the composting is completed. The composting process does not require turning or adding additional microbial agents.

[0055] Example 4 This embodiment provides an aerobic composting process to reduce nitrous oxide production, including the following steps: S1. Mix pig manure and mushroom residue, and adjust the amount of pig manure and mushroom residue to a C / N ratio of C:N=30 and a moisture content of 63% for the mixed substrate. S2. Add 0.7g of nitrifying bacteria agent and 0.7g of DDTC to the mixed substrate obtained in step S1 according to the ratio of 100g dry weight. Mix evenly to form an aerobic fermentation pile with a height-to-width ratio of 3:4 (height:width). Cover the aerobic fermentation pile with a molecular membrane and ensure that the edges of the aerobic fermentation pile are completely covered and sealed. Set an aeration pipe at the bottom of the aerobic fermentation pile. Connect the aeration pipe to a blower and a pipe. S3. Mechanical aeration is used to start composting. It is turned on once every 4 hours, with an aeration rate of 0.2-0.3 L / min per kilogram of mixed substrate, for 20 minutes each time. The temperature of the aerobic fermentation pile is monitored daily. The heating period is 1-3 days, and the high temperature period (pile temperature > 60℃) is 7-12 days. When the temperature is ≤ 40℃, the moisture content is ≤ 30%, and the seed germination index is ≥ 70%, the composting is completed. The composting process does not require turning or adding additional microbial agents.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An aerobic composting process for livestock and poultry solid manure that reduces nitrous oxide production, characterized in that, Includes the following steps: (1) Mix livestock and poultry solid manure and auxiliary materials and adjust the C / N ratio and moisture content to obtain a mixed substrate; (2) Add nitrifying bacteria and denitrification inhibitor to the mixed substrate obtained in step (1) to form an aerobic fermentation pile. Cover the aerobic fermentation pile with a molecular membrane and set up an aeration device at the bottom of the aerobic fermentation pile for aerobic composting. When the temperature of the aerobic fermentation pile is ≤40℃, the moisture content is ≤30%, and the seed germination index is ≥70%, the composting is ended.

2. The process as described in claim 1, characterized in that, In step (1), the C / N ratio of the mixed matrix is ​​C:N = (16-30):1, and the moisture content is 55-63%.

3. The process as described in claim 1, characterized in that, In step (1), the auxiliary materials include at least one of mushroom residue, rice husk, straw, sawdust and wheat straw.

4. The process as described in claim 1, characterized in that, In step (2), the nitrifying agent contains oxidative nitrification promoting bacteria.

5. The process as described in claim 1, characterized in that, In step (2), the amount of nitrifying bacteria agent is 0.3-0.7g of nitrifying bacteria agent per 100g dry weight of mixed substrate.

6. The process as described in claim 1, characterized in that, In step (2), the denitrification inhibitor comprises sodium diethyldithiocarbamate.

7. The process as described in claim 1, characterized in that, In step (2), the amount of denitrification inhibitor used is 0.3-0.7g of denitrification inhibitor per 100g dry weight of mixed matrix.

8. The process as described in claim 1, characterized in that, In step (2), the aeration rate in the aerobic composting is 0.2-0.3 L / min per kilogram of mixed substrate.

9. The application of the process described in any one of claims 1-8 in composting for reducing nitrous oxide emissions.

10. The application of the process according to any one of claims 1-8 in improving the degree of humification of compost products and / or improving seed germination rate.

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