Organic fertilizer for reducing antibiotics and antibiotic resistance genes in livestock and poultry manure based on combination of catalytic pretreatment and decay-promoting compost and preparation method of organic fertilizer

Abstract

The invention discloses an organic fertilizer for reducing antibiotics and antibiotic resistance genes in livestock and poultry manure based on combination of catalytic pretreatment and decay-promoting compost and a preparation method of the organic fertilizer, and relates to the technical field of organic fertilizer and organic solid waste recycling. The method comprises the following steps: firstly, adding a composite catalyst to treat the livestock and poultry manure, and then uniformly mixing the livestock and poultry manure with an acidic fermentation ingredient and a fermentation inoculant for promoting decomposition and composting. The degradation rate of typical antibiotics such as sulfonamides, quinolones, tetracyclines, macrolides and the like in pig manure and cow dung can reach 100%, the degradation rate of typical antibiotic resistance genes such as sulfonamides, quinolones, tetracyclines, macrolides and the like in pig manure and cow dung can reach 95%, and through the synergistic effect of catalytic pretreatment and biological treatment, the degradation rate can reach 100%, and the degradation rate of typical antibiotics such as sulfonamides, quinolones, tetracyclines, macrolides and the like in pig manure and cow dung can reach 95%. The problems that traditional compost antibiotics and antibiotic resistance genes are not thoroughly removed, and the composting period is long are solved, efficient, rapid and low-environmental-risk recycling of the livestock and poultry manure is achieved, and a reliable technical approach is provided for producing high-humic-acid organic fertilizer.

Description

Technical Field

[0001] This invention relates to the field of organic fertilizer and organic solid waste resource utilization technology, specifically to an organic fertilizer and its preparation method based on the combined use of catalytic pretreatment and composting to reduce antibiotics and antibiotic resistance genes in livestock and poultry manure. Background Technology

[0002] In the process of transforming livestock and poultry farming towards large-scale and intensive operations, antibiotics, due to their significant disease prevention and growth-promoting effects, are widely used throughout the entire farming cycle. To reduce the risk of disease transmission under high-density farming and improve feed conversion rates and livestock and poultry slaughter efficiency, the use of antibiotics in the livestock industry has extended from targeted treatment to routine health maintenance and growth promotion, becoming one of the key means to ensure the expansion of the industry's scale. However, the absorption and utilization rate of antibiotics in livestock and poultry is extremely low. Studies have shown that approximately 60%-90% of antibiotics cannot be completely metabolized by the animal body and will eventually be excreted in the form of their original form or structurally stable metabolites in feces, urine, and other excrement. If these livestock and poultry manures containing active antibiotics and metabolites are directly returned to the fields without strict harmless treatment, or are randomly piled up or leaked, they will become a major source of antibiotic and antibiotic resistance genes (ARGs) pollution in the soil, water, and other environments. The continuous accumulation of antibiotics in the environment creates "selective pressure," driving bacteria to acquire resistance through gene mutation or horizontal gene transfer. This leads to the widespread dissemination of antibiotic resistance genes in the microbial community, which not only reduces the therapeutic effect of clinical antibiotics but also transmits them to humans through the food chain, posing a long-term and serious potential threat to the quality and safety of agricultural products, the balance of the ecosystem, and public health.

[0003] Aerobic composting, as a mature technology for the resource utilization of livestock and poultry manure, has become the mainstream method for the treatment of livestock waste because it can achieve multiple goals such as the degradation of organic matter, the killing of pathogenic microorganisms, and the conversion into organic fertilizer. However, traditional aerobic composting technology has several unavoidable limitations when dealing with livestock and poultry manure containing antibiotics and ARGs: First, the antibiotic degradation efficiency is significantly low. For antibiotics with stable chemical structures and resistance to degradation, such as sulfonamides and fluoroquinolones, the natural degradation by microorganisms relied upon by traditional composting is insufficient to completely decompose them, and the residual concentration of some antibiotics may still exceed environmental safety thresholds. Second, the composting cycle is too long. Traditional processes usually require about two months or even longer, which not only occupies a lot of space and labor costs, but may also lead to secondary pollution due to improper control of the composting process, seriously restricting the treatment efficiency and resource turnover speed of livestock and poultry waste. Most importantly, traditional composting has a very limited effect on removing ARGs, especially for stubborn resistance genes such as multidrug resistance genes. The high-temperature stage in the composting process can only partially inactivate the microorganisms carrying ARGs, but it is difficult to destroy the nucleic acid structure of the resistance genes themselves. As a result, ARGs may re-proliferate with the recovery of microorganisms in the later stages of composting, and the final product still has a high risk of resistance gene transmission after being applied to the soil, which cannot fundamentally solve the environmental safety hazards.

[0004] With the increasing scale of livestock and poultry farming, the discharge of livestock waste containing antibiotics and antibiotic resistance genes (ARGs) continues to rise, highlighting environmental pollution and public health risks. The limitations of traditional aerobic composting technology make it difficult for existing treatment methods to meet the practical needs of "efficiently removing antibiotics, effectively reducing ARGs, and rapidly realizing resource recovery." Therefore, there is an urgent need in this field to develop a novel combined treatment technology that scientifically integrates the advantages of chemical pretreatment and biological composting. This technology utilizes chemical action to rapidly destroy the structure of antibiotics and the cell structure of microorganisms, releasing antibiotic resistance genes into the natural environment. Then, through the metabolic activities of functional microbial communities during composting, residual antibiotics and ARGs are deeply degraded, ultimately achieving simultaneous, efficient, and rapid removal of antibiotics and antibiotic resistance genes. Simultaneously, it ensures the fertilizer efficacy and environmental safety of compost products, providing technical support for the harmless and resource-based treatment of livestock and poultry farm waste, and contributing to the green and sustainable development of the livestock industry. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide an organic fertilizer preparation method that can efficiently reduce antibiotic residues in manure and significantly reduce the abundance of antibiotic resistance genes (ARGs). It is applicable to mainstream livestock and poultry manure types such as pig manure and cow manure, and can solve the environmental pollution problems of antibiotics and antibiotic resistance genes caused by large-scale breeding waste, and realize the safe and high-value resource utilization of livestock and poultry manure.

[0006] This invention provides a method for chemical pretreatment combined with biological treatment. This method achieves a 100% degradation rate of typical antibiotics such as sulfonamides, quinolones, tetracyclines, and macrolides in pig and cow manure, and a 95% degradation rate of antibiotic resistance genes in these substances. Through the synergistic effect of catalytic pretreatment and biological treatment, it solves the problems of incomplete removal of antibiotics and antibiotic resistance genes and long composting cycles associated with traditional composting methods. Furthermore, the produced organic fertilizer is of high quality (organic matter content 46.83%~52.70%, total nutrients 7.35%~8.69%, humic content 35.33%~38.19%), achieving efficient, rapid, and low-environmental-risk resource utilization of livestock and poultry manure, and providing a reliable technical approach for the production of high-humic acid organic fertilizer.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing organic fertilizer based on the combined use of catalytic pretreatment and composting to reduce antibiotics and antibiotic resistance genes in livestock and poultry manure, comprising the following steps: S1. After removing impurities from fresh livestock and poultry manure, add a composite catalyst, adjust the pH of the reaction system to 11-13, and react at room temperature for 2-6 hours. S2. After mixing the material obtained in step S1 with the acidic fermentation ingredients, add the fermentation agent to carry out aerobic fermentation, control the pile temperature in the range of 55-70℃, and maintain the high temperature period above 60℃ for at least 7 days. S3. The material after composting in step S2 is subjected to post-maturation treatment to obtain organic fertilizer that reduces antibiotics and antibiotic resistance genes in livestock and poultry manure based on the combined use of catalytic pretreatment and decomposition-promoting composting.

[0008] In a preferred embodiment of the present invention, in step S1, the composite catalyst is two or more of KOH, urea, lignite, and lime; preferably, the composite catalyst is KOH, urea, and / or lignite and lime; more preferably, the composite catalyst is KOH and lignite. When KOH and lignite are selected as the composite catalyst, the mass ratio of KOH to lignite is 1.5~2.5:1; when KOH and urea are selected as the composite catalyst, the mass ratio of KOH to urea is 1.5~2.5:1; when KOH and lime are selected as the composite catalyst, the mass ratio of KOH to lime is 1.5~2.5:1; when KOH, urea, and lignite are selected as the composite catalyst, the mass ratio of KOH, urea, and lignite is 3.5~4.5:1:1.

[0009] In a preferred embodiment of the present invention, in step S1, the ratio of livestock and poultry manure to the dry base of the composite catalyst is 6:1-8:1.

[0010] In a preferred embodiment of the present invention, in step S1, the moisture content of the livestock and poultry manure reaction system is adjusted to 80%-85%.

[0011] In a preferred embodiment of the present invention, in step S2, the acidic fermentation material is agricultural waste treated with Bacillus subtilis. The agricultural waste is at least one of mushroom residue, traditional Chinese medicine residue, straw, and rice husk. The amount of Bacillus subtilis added is 0.1% to 0.5% of the weight of the agricultural waste. The pH of the acidic fermentation material is 4.5 to 5.5. The soluble nutrient content in the acidic fermentation material, on a dry basis, is: available nitrogen 0.2% to 0.5% and soluble carbon 5% to 10%.

[0012] In a preferred embodiment of the present invention, in step S2, the dry matter mass ratio of the acidic fermentation ingredients to the material obtained in step S1 is 3:1-6:1.

[0013] In a preferred embodiment of the present invention, in step S2, the fermentation agent contains Aspergillus niger, Aspergillus oryzae, Aspergillus oryzae var. sp. and Bacillus subtilis.

[0014] In a preferred embodiment of the present invention, in step S2, aerobic fermentation is carried out in an aerobic composting reactor, and during the aerobic fermentation process, the ventilation rate is controlled to be 0.1-0.3 m³ / s. 3 / (m 3 •h), the moisture content of the pile should be maintained at 60%-65%; if the pile temperature >70℃, the ventilation volume needs to be increased to 0.3-0.5 m. 3 / (m 3 •h) Or adjust the turning frequency from once every 2 days to once a day.

[0015] Secondly, the present invention provides an organic fertilizer obtained by the preparation method described above.

[0016] In a preferred embodiment of the present invention, the organic fertilizer contains 46.83% to 52.70% organic matter, 7.35% to 8.69% total nutrients, 35.33% to 38.19% humus, and a seed germination index of 79.73% to 92.57%.

[0017] This invention has at least one of the following beneficial effects: 1. This invention achieves highly efficient reduction of antibiotics and antibiotic resistance genes (ARGs) in livestock and poultry manure through the synergistic effect of "catalytic pretreatment" and "composting." Compared with existing direct composting technologies, which suffer from long treatment cycles, high strain specificity leading to the degradation of only single antibiotics, and drug-resistant bacteria residues, this invention employs a strategy combining chemical and biodegradation. This not only significantly shortens the treatment cycle but also simultaneously degrades multiple antibiotics through non-specific chemical action and directly destroys the cell structure and resistance gene structure of drug-resistant bacteria. Specifically, this invention first uses a composite catalyst to pretreat the manure under suitable and economical alkaline conditions, destroying antibiotic molecules (e.g., breaking ester and amide bonds) and the nucleic acid structure of resistance genes (e.g., breaking phosphodiester bonds and base modification), while simultaneously converting large organic molecules into smaller molecules. This step not only helps to rapidly raise the temperature and shorten the composting cycle in the subsequent composting process but also significantly increases the content of humic acid and fulvic acid, thereby enhancing the fertilizer efficiency of organic fertilizer. More importantly, catalytic pretreatment can chemically degrade antibiotics, kill drug-resistant bacteria, and destroy their genetic material, creating favorable conditions for subsequent biodegradation. Subsequently, the pretreated manure is biodegraded through aerobic composting. During this process, high temperatures and microbial competition further degrade residual antibiotics and inactivate antibiotic resistance genes. This invention can remove most antibiotics and antibiotic resistance genes from livestock and poultry manure through composite catalyst treatment, and then achieve a 69%-100% antibiotic degradation rate and a 28%-91% reduction in the relative abundance and 71%-95% reduction in the copy number of antibiotic resistance genes through subsequent "promoted composting" synergistic treatment.

[0018] 2. This invention employs a composite catalyst for catalytic pretreatment of livestock and poultry manure, achieving not only a good reduction effect on antibiotics and antibiotic resistance genes but also effectively increasing the humic content in the intermediate. Extensive experiments have shown that using a 2:1 mass ratio of KOH to lignite as the composite catalyst results in not only good reduction of antibiotics and antibiotic resistance genes but also the highest humic content in the intermediate. However, the inactivation effect of catalytic pretreatment on microorganisms carrying ARGs is significantly affected by treatment conditions such as catalyst, temperature, and time, leading to insufficient stability and an inability to directly destroy the nucleic acid structure of ARGs, making it difficult to effectively reduce antibiotics and antibiotic resistance genes, and potentially posing a risk of subsequent spread of antibiotics and antibiotic resistance genes. To address these issues, extensive research has revealed that a 6:1-8:1 ratio of livestock and poultry manure to the dry base of the composite catalyst, reacting at room temperature for 2-6 hours, directly destroys the nucleic acid structure of ARGs, achieving effective reduction of antibiotics and antibiotic resistance genes.

[0019] 3. Because the pH of the manure treated with the composite catalyst is high, it cannot be directly added to the fermentation agent for fermentation. To solve this technical problem, this invention adds one or more acidic fermentation ingredients: mushroom residue treated with Bacillus subtilis, traditional Chinese medicine residue, straw, and rice husks. These ingredients have a pH of 4.5-5.5, which is acidic and can lower the pH of the manure treated with the composite catalyst to 6-7, achieving the optimal pH for fermentation. On the other hand, unlike existing technologies where the amount of fermentation additives added is only about 5% of the substrate, the amount of mushroom residue added in this invention is 3-5 times the dry weight of the manure treated with the composite catalyst. This is because the mushroom residue in this invention contains a large amount of soluble nutrients. By adding a large amount of mushroom residue, sufficient nutrition can be provided to the fermentation agent, thereby facilitating rapid temperature rise during the composting stage. The composting temperature can be rapidly raised to above 55°C and maintained at a high temperature of above 60°C for at least 7 days. The high temperature generated during fermentation is used to degrade and inactivate antibiotics and antibiotic resistance genes, thereby further reducing antibiotics and antibiotic resistance genes in livestock and poultry manure.

[0020] In summary, this invention first performs catalytic pretreatment on livestock and poultry manure, utilizing chemical hydrolysis, redox reactions, and structural isomerization to efficiently degrade various antibiotics. Subsequently, it promotes composting, using high temperature and microbial action to further remove antibiotic residues and reduce antibiotic resistance genes (ARGs). Experimental data show that this invention achieves a 100% degradation rate for typical antibiotics such as sulfonamides, quinolones, tetracyclines, and macrolides in pig and cow manure, and a 95% degradation rate for typical antibiotic resistance genes in pig and cow manure. Through the synergistic effect of chemical pretreatment and biological treatment, this invention solves the problems of long composting cycles and incomplete removal of stubborn antibiotics and antibiotic resistance genes in traditional composting methods, achieving efficient, rapid, and low-environmental-risk resource utilization of livestock and poultry manure, and providing a reliable technical approach for the production of high-quality, safe organic fertilizer. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the technical route of the method of the present invention; Figure 2 This is a schematic diagram comparing the degradation rates of multiple antibiotics in pig manure by catalytic pretreatment + composting and conventional composting in Example 1 and Comparative Example 1. Figure 3 This is a schematic diagram illustrating the degradation rate of multiple antibiotics in cow manure by catalytic pretreatment combined with composting in Example 7. Figure 4 This is a schematic diagram illustrating the diversity of antibiotic resistance genes in pig and cow manure after different treatments in Examples 1 and 7. Figure 5This is a schematic diagram showing the relative abundance of four major classes of antibiotic resistance genes in pig and cow manure after different treatments in Examples 1 and 7. Figure 6 These are temperature change graphs during the composting process in Examples 1 and 7.

[0022] Note 1: Figure 2 and Figure 3 In China, sulfonamides include: TMP (trimethoprim); SMM (sulfamethoxypyrimidine); SMT (sulfadimethylpyrimidine); SQX (sulfaquinoxaline); SMX (sulfamethoxypyrimidine); SMZ (sulfamethoxazole); STM (acetylsulfamethoxazole); SDZ (sulfadiazine); and SM (sulfaparamethoxypyrimidine). Quinolones include: ENR (enrofloxacin); CIP (ciprofloxacin); and OFC (ofloxacin). Tetracyclines include: OTC (oxytetracycline); TC (tetracycline); CTC (chlortetracycline); and DOC (doxycycline). Lincomycins include: LIN (clemticum). Macrolides include: TYL (tylosin).

[0023] Note 2: Figure 4 , Figure 5 In the diagram, ZY represents pig manure as raw material; ZK represents pig manure after catalytic pretreatment; ZC represents the product of composting catalytically pretreated pig manure with acidic fermentation ingredients; NY represents cow manure as raw material; NK represents cow manure after catalytic pretreatment; and NC represents the product of composting catalytically pretreated cow manure with acidic fermentation ingredients. Detailed Implementation

[0024] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0025] One embodiment of the present invention provides a method for preparing organic fertilizer by combining catalytic pretreatment and composting to reduce antibiotics and antibiotic resistance genes in livestock and poultry manure. Figure 1 The diagram illustrates the technical approach of this invention, which includes the following steps: (1) Catalytic pretreatment: After removing impurities from fresh livestock and poultry manure, add composite catalyst and add water to adjust the moisture content of the reaction system to 80%-85%. Stir the reaction thoroughly and mix evenly. Adjust the pH value of the mixture to 11-13 and react at room temperature (20-30℃) for 2-6 hours. If the pH is measured to be <11 after 1 hour of reaction, add 0.5%-1% of the dry weight of manure composite catalyst, stir for 30 minutes, and re-measure the pH until the standard is met. The composite catalyst is a mixture of KOH and lignite in a 2:1 ratio, and its addition amount is 10%-15% of the dry weight of manure. The pH value of 11-13 is selected because when the pH is below 11, the hydrolysis / oxidation of antibiotic molecules (such as the piperazine ring of quinolones and the conjugated structure of tetracyclines) is incomplete, and the degradation rate is low; when it is above 13, it will lead to excessive carbonization of organic matter in manure, affecting the activity of subsequent composting microorganisms and increasing the cost of composite catalyst.

[0026] (2) Promoting composting: Mix the material after catalytic pretreatment in step (1) with the acidic fermentation ingredients at a dry matter mass ratio of 1:3 to 1:5. If the moisture content is insufficient, water needs to be added according to calculations. Fermentation inoculants are also added, with the amount of inoculants being 0.5 to 1.5% of the dry weight of the material after catalytic pretreatment in step (1). After mixing evenly, aerobic fermentation is carried out. The acidic fermentation ingredients are agricultural waste treated with Bacillus subtilis. The agricultural waste is at least one of mushroom residue, traditional Chinese medicine residue, straw, and rice husk. Among them, the mushroom residue has a pH of 4.5-5.5, and the soluble nutrient content (on a dry basis) in the mushroom residue is 0.2%-0.5% available nitrogen and 5%-10% soluble carbon. It is used to adjust the pH of the pile to 6-7 and provide the nutrients required for fermentation of the inoculants. During the aerobic fermentation process, the ventilation volume is controlled at 0.1-0.3 m. 3 / (m 3 (h) The moisture content of the stockpile should be maintained at 60%-65%, and the stockpile temperature should be controlled within the range of 55-70℃ through ventilation or turning. If the stockpile temperature is >70℃, the ventilation volume needs to be increased to 0.3-0.5 m. 3 / (m 3 •h) or turning frequency (adjust from once / 2 days to once / day) to avoid microbial inactivation due to high temperature. The high temperature period of the pile above 60℃ should be maintained for at least 7 days, and the total composting cycle (catalytic pretreatment + decomposition composting) is 10-20 days; aerobic fermentation is carried out in an aerobic composting reactor.

[0027] (3) Post-fermentation and packaging: After composting, the material is subjected to post-fermentation treatment under light-proof and ventilated (natural ventilation or intermittent micro-ventilation) conditions, and the ambient temperature is controlled at 15-25℃. After post-fermentation, the material must meet the following requirements: pH 5.5-8.5, organic matter mass fraction (based on dry basis) ≥30%, total nutrient (N+P2O5+K2O) mass fraction (based on dry basis) ≥4%, and seed germination index ≥70%. Then, the material is screened and packaged to obtain the low environmental risk organic fertilizer product.

[0028] In some embodiments, in step (1), when the livestock and poultry manure is cow manure, water is added until the water content of the reaction system is 80%; when the livestock and poultry manure is pig manure, water is added until the water content of the reaction system is 85%.

[0029] In some embodiments, the method of using Bacillus subtilis to treat agricultural waste is as follows: Bacillus subtilis is added to mushroom residue, traditional Chinese medicine residue, straw, or rice husk, and an appropriate amount of water is added. The mixture is then composted for 2-3 days to make the pH of the composted mushroom residue, traditional Chinese medicine residue, straw, or rice husk 4.5-5.5, thus obtaining an acidic fermentation feedstock.

[0030] By adopting the above-described solution, the present invention can achieve the following technical effects: (i) Antibiotic degradation efficiency is significantly improved Through the synergistic effect of "catalytic pretreatment + composting", efficient degradation of different types of antibiotics is achieved, and it is adapted to the differences in pig manure and cow manure. 1. Quinolones: Traditional composting has a degradation rate of less than 40%. When this method treats pig manure, enrofloxacin (ENR) is almost completely removed (>99%) and ciprofloxacin (CIP) is degraded by 69%. When treating cow manure, both ENR and CIP are degraded by 100%.

[0031] 2. Tetracyclines: Traditional composting has a degradation rate of less than 70%. When this method treats pig manure, the degradation rate of oxytetracycline (OTC), chlortetracycline (CTC), and doxycycline (DOC) reaches 96%-98%, and tetracycline (TC) exceeds 80%. When treating cow manure, the degradation rate of TC and CTC is 100%, and that of OTC and DOC is over 90%.

[0032] 3. Sulfonamides: Covering 8 sulfonamide antibiotics (TMP, SMM, SMT, etc.), the degradation rate of pig manure and cow manure remained at 98%-100%. Among them, the degradation rate of sulfamethoxypyrimidine (SMM) was increased from 78% in traditional composting to 100%, and the degradation stability was significantly better than that of traditional composting (the degradation rate of different sulfonamides in traditional composting varies by 76%-90%, while the difference in this method is <5%).

[0033] 4. Other categories: For lincomycin (LIN) and macrolides (TYL), the degradation rate of LIN in pig manure is 85% and that of TYL is 75%; the degradation rate of LIN in cow manure is 99%, filling the gap in traditional composting for the removal of these antibiotics.

[0034] (ii) Highly efficient reduction of antibiotic resistance genes (ARGs) 1. Reduced diversity: After catalytic pretreatment, the Shannon index of ARGs in pig manure decreased from 1.62 to 1.59, and that in cow manure decreased from 4.12 to 3.79; after further composting, the index of ARGs in pig manure decreased further to 1.58, while that in cow manure remained stable at 3.81, thus reducing the diversity of antibiotic resistance genes.

[0035] 2. Relative abundance decrease: A stepwise effect is observed, with the order being "raw material (NY / ZY) > catalytic pretreatment (NK / ZK) > catalytic pretreatment + composting (NC / ZC)". When treating pig manure, the relative abundance of the four major classes of antibiotic resistance genes decreased by 36%-91%; when treating cow manure, the relative abundance of the four major classes of antibiotic resistance genes decreased by 28%-90%, and the copy number of the four major classes of antibiotic resistance genes decreased by 71%-95%.

[0036] 3. Clear mechanism of action: Catalytic pretreatment destroys the microbial cell structure and plasmid DNA, high temperature inactivation of host bacteria in composting and inhibition of ARGs replication through microbial competition, and the two work together to achieve dual control of ARGs through "chemical destruction + biological inhibition".

[0037] (III) Improvement in both processing efficiency and product quality 1. Significantly shortened cycle: The total treatment cycle (catalytic pretreatment + composting) is 15-20 days, which is 55%-66% more efficient than the traditional 45-day composting cycle, making it suitable for the rapid treatment needs of large-scale livestock waste.

[0038] 2. High quality organic fertilizer: The final product has an organic matter content of ≥45% (compared to about 36% for traditional compost), total nutrients (N+P2O5+K2O) ≥7.35% (compared to about 4.2% for traditional compost), humus content of 35.33% (pig manure treatment) and 38.19% (cow manure treatment), and a high seed germination index (92.57% for cow manure treatment). It meets the standards for high-quality organic fertilizer, and antibiotic residues and ARGs abundance are at extremely low levels, significantly reducing the environmental risks to agriculture.

[0039] (iv) Advantages of universality and economy 1. High versatility: By adjusting parameters (such as the amount of regulator added and the mixing ratio), it can efficiently treat livestock and poultry manure with different characteristics, such as pig manure and cow manure, without the need to develop special processes for single types of manure, thus reducing the difficulty of technology promotion.

[0040] 2. Controllable cost: The composite catalyst uses two or more of KOH, urea, lignite, and lime, with an addition amount of only 10%-15% of the dry weight, accounting for less than 10% of the total treatment cost; the composting cycle is short, and the energy consumption (ventilation, turning) is reduced by 30%-40% compared with traditional composting. In addition, various fermentation systems such as windrow and trough can be selected, making it suitable for applications in farms of various sizes and organic fertilizer production enterprises.

[0041] The degradation mechanism of the present invention includes: (a) Mechanisms of antibiotic degradation in livestock and poultry manure 1. Catalytic pretreatment can break the key functional groups of antibiotics through chemical hydrolysis, such as the ester bond of macrolide antibiotics, the amide bond of tetracycline antibiotics, and the ether bond of fluoroquinolone antibiotics.

[0042] 2. Catalytic pretreatment can achieve free radical and electron transfer through redox reactions, such as turning heavy metal ions into free radical superoxide anions, and then forming small molecule compounds through carboxylation ring-opening reactions; and turning sulfonamide antibiotics into aniline derivatives through deamination reactions.

[0043] 3. Microbial degradation can promote the proliferation of alkali-resistant microorganisms, and peroxidase and laccase can be activated in an alkaline environment. Through the secretion of esterase and amidase by alkali-resistant microorganisms, tetracycline antibiotics are decomposed into small molecule peptides, and fluoroquinolones are decomposed into ketones and sulfoxides through peroxidase and laccase.

[0044] 4. Catalytic pretreatment can cause antibiotics to undergo structural isomerization and deprotonation, thereby altering their spatial structure. For example, deprotonation of penicillins yields penicillin-thiazolic acid, and the β-lactam ring is more easily attacked by hydrolytic enzymes. It can also break the conjugated structure of tetracyclines into isotetracyclines. Furthermore, it can transform the chair-shaped piperazine ring in fluoroquinolones into a boat-shaped piperazine ring. The cyclic piperazine ring undergoes a conformational change, making it unable to bind to bacterial DNA gyrases and more easily degraded by hydrolytic enzymes.

[0045] (II) Mechanisms of antibiotic resistance gene degradation in livestock and poultry manure 1. Catalytic pretreatment can disrupt the nucleic acid structure of antibiotic resistance genes, including hydrolytic breakage of phosphodiester bonds, base modification and pairing failure, double-strand unwinding and conformational disruption, thereby causing gene breakage.

[0046] 2. Catalytic pretreatment can disrupt cell membranes, inhibit metabolism and inactivate enzymes, and alter community structure, thereby inactivating host microorganisms and reducing replication and release.

[0047] 3. Catalytic pretreatment can inhibit plasmid degradation and replication, as well as block the function of transposons and integrons, thereby inactivating mobile genetic elements and blocking horizontal transfer.

[0048] 4. Alkaline conditions can activate nucleases, accelerating the degradation of free antibiotic resistance genes; OH - It can competitively bind to the active sites of organic matter (such as carboxyl groups and phenolic hydroxyl groups), causing the antibiotic resistance gene to dissociate and be released from the complex, which is conducive to nuclease degradation. Therefore, catalytic pretreatment can achieve nuclease activation and synergistic degradation, thereby degrading the gene.

[0049] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following specific embodiments.

[0050] The fermentation agents used in the following examples are commercially available, specifically purchased from the Chengdu Institute of Biology, Chinese Academy of Sciences, and contain Aspergillus niger, Aspergillus oryzae, Aspergillus oryzae var. sp. and Bacillus subtilis.

[0051] The mushroom residue used in the following examples was formed by adding Bacillus subtilis to commercially available mushroom residue and composting it for 3 days; wherein, the amount of Bacillus subtilis added was 0.3% of the weight of commercially available mushroom residue, the pH of the mushroom residue formed after composting was 5, and the soluble nutrient content (on a dry basis) was 0.4% available nitrogen and 8% soluble carbon.

[0052] Unless otherwise specified, the experimental methods and materials used in the following embodiments are conventional methods and commonly available materials. Where specific techniques or conditions are not specified in the embodiments, they should be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions.

[0053] Example 1: Treatment of pig manure (1) Catalytic pretreatment: Take fresh pig manure, remove impurities, add composite catalyst (KOH and lignite mixed at a mass ratio of 2:1), the ratio of livestock and poultry manure to composite catalyst is 8:1, and adjust the water content of the reaction system to 85%. Stir mechanically for 30 minutes to allow it to react fully and mix evenly. The pH of the mixture is measured to be 12.1. Let it stand at room temperature (about 25°C) for 4 hours to obtain pig manure treated with composite catalyst (pig manure intermediate).

[0054] (2) Accelerated composting: The reacted material (pig manure treated with the composite catalyst) and the crushed mushroom residue (pH 5.0) are mixed evenly at a dry matter mass ratio of 1:4 to obtain a mixture with a pH of 7.2 (meeting the requirements of compost pH 6.5-8.0); a fermentation agent is added at a rate of 1% of the mass of the pig manure treated with the composite catalyst. After mixing evenly, the mixture is transferred to an aerobic composting reactor and subjected to intermittent forced ventilation at a ventilation rate of 0.2 m³ / min. 3 / (m 3•h), the moisture content of the pile was maintained at 62%, and the pile temperature was controlled to rise above 50°C on the second day and maintained above 60°C for 7 days. During this period, when the pile temperature reached a maximum of 67.7°C, the ventilation volume was increased to 0.3m³. 3 / (m 3 After 12 hours, the temperature dropped to 60.5℃. The total composting cycle was 15 days.

[0055] (3) Post-fermentation and packaging: After composting, the material was moved to the aging workshop and aged for 5 days under natural ventilation at 20℃. The moisture content of the material was measured to be 28%, pH 8.65, organic matter mass fraction (based on dry basis) 52.70%, total nutrient (N+P2O5+K2O) mass fraction (based on dry basis) 8.69%, and seed germination index 79.73%. Organic fertilizer product A was obtained after sieving.

[0056] Example 2 The only difference from Example 1 is that in step (1), the composite catalyst is obtained by mixing KOH and urea at a mass ratio of 2:1, and the pH of the mixture is measured to be 11.6. The other steps are the same as in Example 1.

[0057] The prepared intermediate was found to contain 24.48% humic substances.

[0058] Example 3 The only difference from Example 1 is that in step (1), the composite catalyst is obtained by mixing KOH with urea and lignite in a mass ratio of 4:1:1, and the pH of the mixture is measured to be 11.8. The other steps are the same as in Example 1.

[0059] The prepared intermediate was found to contain 26.72% humic substances.

[0060] Example 4 The only difference from Example 1 is that in step (1), the composite catalyst is obtained by mixing KOH and lime at a mass ratio of 2:1, and the pH of the mixture is measured to be 12.5. The other steps are the same as in Example 1.

[0061] The prepared intermediate was found to contain 19.65% humic substances.

[0062] Example 5 The only difference from Example 1 is that in step (1), the ratio of livestock and poultry manure to composite catalyst dry basis is 6:1, and the pH of the mixture is measured to be 12.8. The other steps are the same as in Example 1.

[0063] The prepared intermediate was found to contain 31.65% humic substances.

[0064] Example 6 The only difference from Example 1 is that in step (2), the reacted material (pig manure treated with composite catalyst) and the crushed mushroom residue (pH 5.0) are mixed at a dry matter mass ratio of 1:6, and the pH of the mixture is 6.8 (which meets the requirements of compost pH 6.5-8.0). The other steps are the same as in Example 1.

[0065] Comparative Example 1: Traditional composting treatment of pig manure Pig manure from the same source as in Example 1 was taken, impurities were removed, and it was directly mixed with mushroom residue (pH 5.0) treated in an equal proportion for conventional aerobic composting with a ventilation rate of 0.2 m³ / s. 3 / (m 3 •h), the temperature of the compost pile naturally rises and falls, with a high-temperature period (above 55℃) maintained for 3 days), and the composting cycle is 45 days. After composting, it is aged for 5 days at 20℃ under natural ventilation conditions. The measured material moisture content is 29%, pH is 7.5, organic matter mass fraction (on a dry basis) is 36.26%, total nutrient (N+P2O5+K2O) mass fraction (on a dry basis) is 4.16%, and seed germination index is 74.16%, yielding organic fertilizer product B.

[0066] Comparative Example 2 The only difference from Example 1 is that in step (1), the composite catalyst was replaced with a single catalyst KOH, and the pH of the mixture was measured to be 12.8. The other steps are the same as in Example 1.

[0067] The prepared intermediate was found to contain only 21.23% humic substances. Therefore, although the pH of the mixture was between 11 and 13 after treatment with a single catalyst KOH, it was not conducive to increasing the humic substance content in the intermediate.

[0068] Comparative Example 3 The only difference from Example 1 is that in step (1), the ratio of livestock and poultry manure to composite catalyst dry basis is 10:1, and the pH of the mixture is measured to be 11.6. The other steps are the same as in Example 1.

[0069] The results showed that the humic content in the prepared intermediate was only 16.23%. Therefore, the addition ratio of the composite catalyst was too low, which was not conducive to increasing the humic content in the intermediate.

[0070] Furthermore, the comparative example showed a worse reduction effect on antibiotics and antibiotic resistance genes than Example 1, indicating that the proportion of the composite catalyst added affects the reduction effect on antibiotics and antibiotic resistance genes.

[0071] Comparative Example 4 The only difference from Example 1 is that in step (1), the water content of the reaction system is adjusted to 75%, and the other steps are the same as in Example 1.

[0072] Because too little water was added, the reaction system formed clumps, which was not conducive to subsequent reactions.

[0073] Comparative Example 5 The only difference from Example 1 is that in step (2), the reacted material (pig manure treated with composite catalyst) and the crushed mushroom residue (pH 5.0) are mixed at a dry matter mass ratio of 1:2. The rest is the same as in Example 1.

[0074] The pH of the mixture was measured to be 8.4, which does not meet the requirement of pH 6.5-8.0 for composting.

[0075] Comparative Example 6 The only difference from Example 1 is that in step (2), no fermentation agent is added, while the other steps are the same as in Example 1.

[0076] Experiments showed that aerobic composting failed when the temperature remained at room temperature.

[0077] Comparative Example 7 The only difference from Example 1 is that in step (2), “mushroom residue” is replaced with “commercially available mushroom residue”, that is, it is not treated with Bacillus subtilis. The other steps are the same as in Example 1.

[0078] Experiments revealed that, firstly, the pH of untreated commercially available mushroom residue is approximately 5.5–7.5, which is insufficient to lower the pH of the manure treated with the composite catalyst to 6–7, thus failing to achieve the optimal pH for microbial fermentation. Secondly, the untreated commercially available mushroom residue has a low content of soluble nutrients, which cannot provide sufficient nutrition for the fermentation agent. This hinders rapid temperature rise during the composting stage and prevents the composting temperature from rapidly increasing to above 55°C and maintaining a high temperature period above 60°C for at least 7 days. Consequently, the reduction effect on antibiotics and antibiotic resistance genes is worse than in Example 1.

[0079] Comparative Example 8 The only difference from Example 1 is that in step (2), “mushroom residue” is replaced with “straw that has not been treated with Bacillus subtilis”, and the other steps are the same as in Example 1.

[0080] Experiments showed that aerobic composting failed when the temperature remained at room temperature.

[0081] Comparative Example 9 The only difference from Example 1 is that in step (2), “mushroom residue” is replaced with “Chinese herbal medicine residue that has not been treated with Bacillus subtilis”, and the other steps are the same as in Example 1.

[0082] Experiments showed that aerobic composting failed when the temperature remained at room temperature.

[0083] Comparative Example 10 The only difference from Example 1 is that in step (2), the "mushroom residue" is replaced with "rice husks that have not been treated with Bacillus subtilis". The other steps are the same as in Example 1.

[0084] Experiments showed that aerobic composting failed when the temperature remained at room temperature.

[0085] Example 7: Treatment of cow dung (1) Catalytic pretreatment: Take fresh cow dung, remove impurities and add a composite catalyst accounting for 12.5% ​​of the dry weight of cow dung, adjust its moisture content to 80%, stir and mix well, and measure the pH of the mixture to be 11.96. React at room temperature for 4 hours to obtain cow dung treated with composite catalyst (cow dung intermediate).

[0086] (2) Accelerated composting: The reacted material (cow manure treated with the composite catalyst) and the crushed mushroom residue (pH 5.0) were mixed at a dry matter mass ratio of 1:4. Fermentation inoculant was added, with the amount of inoculant being 1% of the mass of the pig manure treated with the composite catalyst. After mixing evenly, composting was carried out in an aerobic composting reactor. The moisture content of the compost pile was maintained at 62%. Aeration and temperature control were achieved by turning the pile, and the ventilation rate was maintained at 0.25 m³. 3 / (m 3 •h). Maintain the compost pile temperature above 60℃ for 7 days, with a total composting cycle of 15 days.

[0087] (3) Post-fermentation and packaging: After composting, the material was aged for 5 days at 22℃ with intermittent micro-ventilation. The moisture content of the material was 27%, pH 8.08, organic matter mass fraction (based on dry basis) 46.83%, total nutrient (N+P2O5+K2O) mass fraction (based on dry basis) 7.35%, and seed germination index 92.57%. After sieving, organic fertilizer product C was obtained.

[0088] Effect detection: The effects of the organic fertilizers prepared in Examples 1, 7, and 1 were tested, and the results are as follows: I. Characteristic Analysis of Livestock and Poultry Manure Products Based on Catalytic Pretreatment and Promoting Composting The characteristics of the organic fertilizer products prepared in Examples 1-2 and Comparative Example 1 were analyzed, and the results are shown in Table 1.

[0089] Table 1. Data on livestock and poultry manure products from catalytic pretreatment + accelerated composting. As shown in Table 1, after catalytic pretreatment and composting, the organic matter content of livestock and poultry manure is 46.83%~52.70%, the humus content is 35.33%~38.19%, the seed germination index is 79.73%~92.57% (36.26% for traditional compost), and the total nutrients (N+P2O5+K2O) are 7.35%~8.69% (approximately 4.16% for traditional compost). The humus content reaches 35.33% (pig manure treatment) and 38.19% (cow manure treatment), and the seed germination index is high (92.57% for cow manure treatment), meeting the standards for high-quality organic fertilizer.

[0090] Furthermore, the composting cycle of Example 1 is 15 days, while the total composting cycle of Comparative Example 1 is 45 days. In comparison, the efficiency of the present invention is increased by 66%, and the humus content is as high as 35.33%.

[0091] II. Effects of catalytic pretreatment + composting on antibiotic changes in livestock and poultry manure (1) Antibiotic content: The content of antibiotics in the raw materials, intermediates and prepared organic fertilizers in Examples 1, 7 and Comparative Example 1 was determined by ultrasonic extraction-solid phase extraction-high performance liquid chromatography-tandem mass spectrometry in T / GDSES 3-2022 Determination of Antibiotic Compounds in Soil. The results are shown in Tables 2 and 3.

[0092] Table 2 Table 3 As can be seen from Tables 2 and 3, the content of antibiotics in the organic fertilizers prepared in Examples 1 and 7 is very low, far lower than that in traditional compost.

[0093] (2) Degradation rate of antibiotics in pig manure: Degradation rate = [(antibiotics in pig manure raw material before treatment - antibiotics in pig manure after treatment) / antibiotics in pig manure raw material before treatment] × 100%.

[0094] The results are as follows Figure 2 As shown, the method of this invention (organic fertilizer product A) significantly increases the degradation rate of typical antibiotics such as quinolones and tetracyclines in pig manure compared to traditional compost (organic fertilizer product B). According to experimental data, the degradation rate of enrofloxacin (ENR) and sulfamethoxypyrimidine (SMM) increased from partial degradation in traditional compost to near-complete removal (>99%); the degradation rate of tetracycline drugs such as oxytetracycline (OTC) and chlortetracycline (CTC) also increased from less than 70% in traditional compost to over 96%.

[0095] The specific degradation process is as follows: (1) Quinolone antibiotics: from partial degradation to near 100% removal. For commonly used quinolone drugs such as enrofloxacin (ENR), ciprofloxacin (CIP), and ofloxacin (OFC), the degradation rate of traditional composting is generally less than 50% (e.g., the degradation rate of ENR in traditional composting is less than 40%). However, catalytic pretreatment + accelerated composting can increase the degradation rate of ciprofloxacin (CIP) to 69%, and enrofloxacin (ENR) is almost completely removed, which completely solves the problem of incomplete degradation of this type of antibiotic by traditional composting.

[0096] (2) Tetracycline antibiotics: Degradation rate exceeds 80%, significantly improving the shortcomings of traditional composting. Tetracycline antibiotics such as oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOC) have stable chemical structures, and the degradation rate of traditional composting is generally less than 70% (for example, the degradation rate of chlortetracycline CTC in traditional composting is only about 50%). The catalytic pretreatment + humification composting technology, through the synergistic effect of "humification pretreatment + short-range high-temperature composting", enables the degradation rate of tetracycline (TC) to exceed 80%, of which the degradation rates of oxytetracycline (OTC), chlortetracycline (CTC), and doxycycline (DOC) reach 96%-98%, effectively solving the problem of tetracycline antibiotic residues.

[0097] (3) Sulfonamide antibiotics: High degradation rate covering all categories, with outstanding efficacy of key drugs. For eight sulfonamide antibiotics, including sulfamethoxypyrimidine (SMM), sulfadimethoxazole (SMT), and sulfamethoxazole (SMZ), the degradation rate of catalytic pretreatment + composting was maintained at 98%-100%. Among them, the degradation rate of sulfamethoxypyrimidine (SMM) increased significantly from 78% in traditional composting to 100%, basically achieving complete removal of sulfonamide antibiotics. Moreover, the degradation stability was significantly better than that of traditional composting (the degradation rate of different sulfonamide drugs in traditional composting varied by 76%-90%). In addition, for lincomycin (lin) and macrolide (tylosin TYL) antibiotics, catalytic pretreatment + composting still showed stable degradation ability.

[0098] (3) Antibiotic degradation rate in cow dung: The results are as follows Figure 3 As shown, its degradation rate of antibiotics such as oxytetracycline (OTC), chlortetracycline (CTC), and tylosin (TYL) in cow dung all reached over 90%, with the degradation rate of doxycycline (DOC) also exceeding 90%.

[0099] The specific degradation process is as follows: (1) Sulfonamides and quinolones: Nearly complete removal. The degradation rates of sulfonamides such as trimethoprim (TMP) and sulfamethoxypyrimidine (SMM), as well as quinolones such as enrofloxacin (ENR) and ciprofloxacin (CIP), all reached 100%. Only sulfaquinoxaline (SQX) had a slightly lower degradation rate (95%). Overall, the degradation performance was better than that of the same class of antibiotics in the pig manure system. (2) Tetracyclines: Stable and efficient degradation. The degradation rates of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOC) are all maintained at 90%-100%, among which chlortetracycline (CTC) and tetracycline (TC) have a degradation rate of 100%.

[0100] (3) Lincomycins: filling the gap in traditional composting. The degradation rate of lincomycin (LIN) reaches 99%. This technology provides a feasible solution for the removal of lincomycin antibiotics from cow manure, avoiding the entry of such antibiotics into the soil environment with the application of manure.

[0101] III. Effects of catalytic pretreatment + composting on the diversity of antibiotic resistance genes in livestock and poultry manure The diversity of antibiotic resistance genes in the pig manure raw material (ZY), the prepared organic fertilizer product A (ZC), and the pig manure treated with the composite catalyst (ZK) in Example 1, and the cow manure raw material (NY), the prepared organic fertilizer product C (NC), and the cow manure treated with the composite catalyst (NK) in Example 2 were detected. The results are shown in […]. Figure 4 .

[0102] like Figure 4 As shown, compared with pig manure raw material (ZY), the diversity of antibiotic resistance genes (Shannon index) in pig manure treated with composite catalyst (ZK) decreased, confirming that catalytic pretreatment can reduce the diversity of antibiotic resistance genes in different types of livestock and poultry manure.

[0103] like Figure 4 As shown, compared with raw cow manure (NY), the diversity of antibiotic resistance genes (Shannon index) in cow manure treated with composite catalyst (NK) decreased, confirming that catalytic pretreatment can reduce the diversity of antibiotic resistance genes in different types of livestock and poultry manure.

[0104] Therefore, the diversity of antibiotic resistance genes (Shannon index) in pig and cow manure tends to decrease after catalytic pretreatment.

[0105] IV. Effects of catalytic pretreatment + composting on the relative abundance of antibiotic resistance genes in livestock and poultry manure Antibiotic resistance gene abundance: High-throughput quantitative PCR was used to detect ARGs in pig manure raw material (ZY), organic fertilizer product A prepared in Example 1 (ZC), pig manure treated with composite catalyst (ZK), and cow manure raw material (NY), organic fertilizer product C prepared in Example 7 (NC), and cow manure treated with composite catalyst (NK). The results are shown in Tables 4-5 and 5. Figure 5 .

[0106] Table 4 As shown in Table 4, the relative abundance of antibiotic resistance genes in livestock and poultry manure gradually decreased after catalytic pretreatment and composting.

[0107] As shown in Table 5, the copy numbers of the four major categories of antibiotic resistance genes were the highest in pig manure and cow manure raw materials, and decreased after catalytic pretreatment. However, after the "catalytic pretreatment + composting" of this invention, the copy number of antibiotic resistance genes decreased by 71%-95%, showing a decreasing trend of raw material (NY / ZY) > catalytic pretreatment (NK / ZK) > catalytic pretreatment + composting (NC / ZC), which confirms the universality of the method of this invention for different types of livestock and poultry manure.

[0108] Table 5 like Figure 5 As shown, after catalytic pretreatment and composting, the relative abundance of antibiotic resistance genes in the four major classes of cattle manure increased except for fluoroquinolones, while the other three classes of antibiotics decreased; in pig manure, except for macrolides, the other three classes of antibiotics increased.

[0109] V. Temperature Changes During the Composting Process of Livestock and Poultry Manure The temperature changes and room temperature conditions during the composting process in Examples 1 and 2 are shown in Table 6 and... Figure 6 As shown: Table 6 From Table 6 and Figure 6 It can be seen that the high temperature period (55-70℃) for promoting composting in Example 1 is 9 days, and the high temperature period (55-70℃) for promoting composting in Example 7 is 7 days, with a composting cycle of 15 days, while the total cycle of traditional composting is about 45 days, thus improving composting efficiency by 66%.

[0110] In summary, this invention creatively solves the industry pain points of difficult and time-consuming removal of antibiotics and antibiotic resistance genes in livestock and poultry manure treatment by organically combining catalytic pretreatment and composting, providing reliable technical support for the production of high-quality and safe organic fertilizer.

[0111] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing organic fertilizer based on the combined use of catalytic pretreatment and composting to reduce antibiotics and antibiotic resistance genes in livestock and poultry manure, characterized in that, Includes the following steps: S1. After removing impurities from fresh livestock and poultry manure, add a composite catalyst, adjust the pH of the reaction system to 11-13, and react at room temperature for 2-6 hours. S2. After mixing the material obtained in step S1 with the acidic fermentation ingredients, add the fermentation agent to carry out aerobic fermentation, control the pile temperature in the range of 55-70℃, and maintain the high temperature period above 60℃ for at least 7 days. S3. The material after composting in step S2 is subjected to post-maturation treatment to obtain organic fertilizer that reduces antibiotics and antibiotic resistance genes in livestock and poultry manure based on the combined use of catalytic pretreatment and decomposition-promoting composting.

2. The preparation method according to claim 1, characterized in that, In step S1, the composite catalyst is two or more of KOH, urea, lignite, and lime. When KOH and lignite are selected as the composite catalyst, the mass ratio of KOH to lignite is 1.5~2.5:1; When KOH and urea are selected as the composite catalyst, the mass ratio of KOH to urea is 1.5~2.5:1; When KOH and lime are selected as the composite catalyst, the mass ratio of KOH to lime is 1.5~2.5:1; When the composite catalyst is selected from KOH, urea and lignite, the mass ratio of KOH, urea and lignite is 3.5~4.5:1:

1.

3. The preparation method according to claim 1, characterized in that, In step S1, the ratio of livestock and poultry manure to dry composite catalyst is 6:1-8:

1.

4. The preparation method according to claim 1, characterized in that, In step S1, the moisture content of the livestock and poultry manure reaction system is adjusted to 80%-85%.

5. The preparation method according to claim 1, characterized in that, In step S2, the acidic fermentation material is agricultural waste treated with Bacillus subtilis. The agricultural waste is at least one of mushroom residue, traditional Chinese medicine residue, straw, and rice husk. The amount of Bacillus subtilis added is 0.1% to 0.5% of the weight of the agricultural waste. The pH of the acidic fermentation material is 4.5 to 5.

5. The soluble nutrient content in the acidic fermentation material, on a dry basis, is: available nitrogen 0.2% to 0.5% and soluble carbon 5% to 10%.

6. The preparation method according to claim 1, characterized in that, In step S2, the dry matter mass ratio of the acidic fermentation ingredients to the material obtained in step S1 is 3:1 to 6:

1.

7. The preparation method according to claim 1, characterized in that, In step S2, the fermentation agent contains Aspergillus niger, Aspergillus oryzae, Aspergillus oryzae var. sp. and Bacillus subtilis.

8. The preparation method according to claim 1, characterized in that, In step S2, aerobic fermentation is carried out in an aerobic composting reactor. During the aerobic fermentation process, the ventilation rate is controlled at 0.1-0.3 m³ / s. 3 / (m 3 •h), the moisture content of the pile should be maintained at 60%-65%; if the pile temperature >70℃, the ventilation volume needs to be increased to 0.3-0.5 m. 3 / (m 3 •h) Or adjust the turning frequency from once every 2 days to once a day.

9. An organic fertilizer, characterized in that, It is obtained by the preparation method described in claims 1 to 8.

10. The organic fertilizer according to claim 9, characterized in that, The organic fertilizer contains 46.83% to 52.70% organic matter, 7.35% to 8.69% total nutrients, 35.33% to 38.19% humus, and a seed germination index of 79.73% to 92.57%.

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