Method for preparing organic fertilizer by resource utilization of pickled vegetable residues

Abstract

The invention relates to the technical field of resource utilization of agricultural wastes, and discloses a method for preparing an organic fertilizer by resource utilization of pickled vegetable residues, which comprises the following steps: step 1, pretreatment; 2, inoculating a composite strain accounting for 3% of the dry weight of the rotten vegetable leaves, wherein the total bacterial amount is greater than or equal to 1.5 * 10 < 9 > CFU / g; step 3, segmented fermentation: the first stage is an acid production-sodium discharge stage, and the second stage is a desalination-flocculation stage; step 4, carrying out solid-liquid separation; step five, performing secondary fermentation; and step 6, quality regulation and packaging. According to the method disclosed by the invention, efficient desalination and organic matter degradation in a high-salt environment are realized through division and cooperation of bacillus amyloliquefaciens dominated exopolysaccharide (EPS) synthesis, salt-tolerant single cell active sodium removal, salt-tolerant lactobacillus plantarum acid production and infectious microbe inhibition, and salt-tolerant saccharomyces cerevisiae osmotic pressure regulation; the first-stage acid sodium removal and the second-stage desalination flocculation control are matched with the microbial metabolism rule to improve the efficiency, high-salt inhibition is avoided, and efficient resource utilization of the pickled vegetable leftovers is achieved.

Description

Technical Field

[0001] This invention relates to the field of agricultural waste resource utilization technology, specifically a method for preparing organic fertilizer from kimchi tails. Background Technology

[0002] Pickled vegetables, a traditional fermented food with Chinese characteristics, have formed a complete industrial chain covering raw material planting, processing, manufacturing, logistics, and sales, becoming one of the important pillar industries in my country's food processing sector. However, the pickled vegetable industry generates a large amount of processing by-products, namely pickled vegetable tails. These tails mainly include substandard vegetable leaves and roots removed before pickling, as well as substandard vegetable parts generated during the pickling process, accounting for 20%-30% of the total weight of raw materials used in pickled vegetable processing.

[0003] Analysis revealed that kimchi waste exhibits three key characteristics: high salt content (generally exceeding 14% based on sodium chloride (NaCl)), high moisture content (ranging from 75% to 85%), making it prone to rotting and spoilage, and susceptible to the growth of harmful microorganisms and foul odors during storage; and high organic matter content, rich in various usable components. However, this combination of characteristics makes the processing of kimchi waste extremely difficult. Direct composting results in a high-salt environment that inhibits microbial activity, leading to a long fermentation cycle, low organic matter degradation (typically <40%), and insufficient desalination efficiency (Cl⁻ reduction rate <30%). Existing methods for processing kimchi waste primarily include: 1. Directly returning the soil to the field has limited applicability due to its high salinity, which can easily lead to soil compaction. 2. Dehydration and drying methods are energy-intensive and do not solve the problems of salt and organic matter degradation. 3. Microbial fermentation: Conventional strains, such as common Bacillus subtilis, have poor salt tolerance, with an upper limit of salt tolerance <5% NaCl; they cannot metabolize efficiently in high-salt environments, and their desalination and degradation efficiencies are insufficient. Therefore, there is an urgent need to develop a technology for the resource utilization of kimchi waste that combines efficient desalination and organic matter degradation with the preparation of organic fertilizer. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing organic fertilizer by utilizing kimchi waste, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for resource utilization of kimchi waste to prepare organic fertilizer, comprising the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, and add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, and pile for 2 hours; Step 2: Inoculate with compound microbial strain at 3% of the dry weight of the vegetable tails, with a total bacterial count ≥1.5×10⁹ CFU / g; Step 3: Segmented fermentation. The first stage (0-72 hours) is the acid production and sodium excretion period, with the temperature controlled at 30±2℃ and humidity at 60%±5%, and the pile turned over every 12 hours. The second stage (72-120 hours) is the desalination and flocculation period, with the temperature increased to 45±3℃ and humidity at 55%±5%. 10% corn stalk powder is added by mass, and the pile is covered with a breathable membrane to control the oxygen concentration to <2%. Step 4: Solid-liquid separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the mixture using a screw press until the moisture content reaches 45-50%. Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, then transfer to an aging tank to age until the moisture content is ≤30%; Step Six: Quality Control and Packaging: Test and adjust the Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium content of the final product, and seal it in a moisture-proof composite bag.

[0006] Preferably, the compound microbial strain comprises the following components in the following mass ratios: 30%-40% Bacillus amyloliquefaciens, 45%-55% halophilic bacteria, 5%-15% halophilic lactobacillus plantarum, and 2%-8% halophilic brewer's yeast.

[0007] Preferably, in the pretreatment step, the zeolite has an adsorption capacity of 0.5 mmol / g and is used to adsorb Na ions in the kimchi tail.

[0008] Preferably, in the first stage of the three-stage fermentation, Bacillus amyloliquefaciens, halophilic Lactobacillus plantarum, and halophilic Halomonas work together to achieve acid production and sodium excretion; in the second stage, Bacillus amyloliquefaciens, halophilic Halomonas, and halophilic Saccharomyces cerevisiae work synergistically to complete desalination and flocculation.

[0009] Preferably, in step four, the solid-liquid separation step, a screw press with an aperture of 0.3 mm is used to ensure that the moisture content of the separated solid material is reduced to 45-50%.

[0010] Preferably, during the second fermentation in step five, the solid material is transferred to a constant temperature aerobic fermentation machine and fermented at 50-60℃ for 5 hours to avoid high temperature damaging the organic matter. Then it is transferred to an aging tank and turned over every 48 hours until the material temperature is close to the room temperature and the moisture content drops to below 30%, thus obtaining a low-salt organic fertilizer semi-finished product.

[0011] Preferably, in step six, quality control and packaging, if the Cl⁻ content is detected to be >3%, 5% humic acid is added to adjust nutrients and complex Cl⁻; if the pH value is <5.5, 1% lime powder is added to neutralize the acidity.

[0012] Preferably, during quality control in step six, the detection indicators are: Cl⁻ content ≤3%, organic matter ≥30%, pH value 5.5-7.5, and total nitrogen, phosphorus, and potassium ≥4%.

[0013] Preferably, Bacillus amyloliquefaciens is used to dominate the synthesis of extracellular polysaccharides and the decomposition of organic matter, halophilic halometa is used to actively excrete sodium and balance the salt concentration in the environment, halophilic Lactobacillus plantarum is used to produce acid to regulate pH and inhibit other bacteria, and halophilic Saccharomyces cerevisiae is used to regulate osmotic pressure and mask salinity.

[0014] Preferably, the salt tolerance limits for each bacterial species in the compound microbial agent are as follows: Bacillus amyloliquefaciens ≥10% NaCl, salt-tolerant Halomonas ≥15% NaCl, salt-tolerant Lactobacillus plantarum ≥12% NaCl, and salt-tolerant Saccharomyces cerevisiae ≥14% NaCl.

[0015] Compared with the prior art, the beneficial effects of the present invention are: The composite microbial strains in this invention exhibit strong functional synergy: through the division of labor and cooperation of Bacillus amyloliquefaciens leading the synthesis of extracellular polysaccharides (EPS), halophilic halometabolites actively excreting sodium, halophilic Lactobacillus plantarum producing acid to suppress other bacteria, and halophilic Saccharomyces cerevisiae regulating osmotic pressure, efficient desalination and organic matter degradation are achieved under high-salt conditions, with a Cl⁻ reduction rate >60%. The process parameters were optimized in stages. The temperature, humidity and turning of the first stage (30℃ for acid production and sodium removal) and the second stage (45℃ for desalination and flocculation) were controlled to match the microbial metabolic patterns and improve efficiency. The carrier adsorbed zeolite and biochar to reduce the initial salt load and avoid high salt inhibition. The product meets the standards, with the final organic fertilizer semi-finished product having an organic matter content of ≥30%, Cl⁻≤3%, total nitrogen, phosphorus and potassium content of ≥4%, and pH of 5.5-8.5, fully meeting the requirements of NY525-2021 organic fertilizer.

[0016] The parts of the device not covered herein are the same as or can be implemented using existing technologies. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for preparing organic fertilizer by utilizing kimchi waste from kimchi according to the present invention; Figure 2 This is a process flow diagram of a method for preparing organic fertilizer by utilizing kimchi waste from kimchi according to the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] Example 1: Please refer to Figure 1 , Figure 2 This invention provides a technical solution: a method for resource utilization of kimchi waste to prepare organic fertilizer. This method achieves efficient desalination of kimchi waste, deep degradation of organic matter, and standardized organic fertilizer preparation through precise matching of the synergistic metabolism of salt-tolerant compound microorganisms and a segmented fermentation process. The method includes the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, and add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, then pile for 2 hours. The crushed kimchi tails can increase the contact area between the tails and the subsequent adsorbents and microorganisms, providing favorable conditions for subsequent adsorption, desalination and microbial degradation. Pressing is to avoid the problem of reduced microbial metabolic efficiency and easy growth of miscellaneous bacteria caused by excessive moisture content, and to prevent the impact of excessively low moisture content on microbial activity. In the pretreatment step of Step 1, the adsorption capacity of zeolite is 0.5mmol / g, which is used to adsorb Na ions in the kimchi tails. Adding 2% zeolite and 3% biochar by mass, where zeolite can specifically adsorb Na⁺ in kimchi tails, and biochar helps to enhance the adsorption effect and provides a certain pore structure, the two work together to reduce the initial free salt concentration to 12%±1%, effectively reducing the initial salt load and avoiding the inhibition of subsequent microbial colonization by the high salt environment. Step 2: Inoculate the compound microbial strain at 3% of the dry weight of the vegetable tails, with a total microbial count ≥1.5×10⁹ CFU / g; the compound microbial strain includes the following components in the following mass ratio: Bacillus amyloliquefaciens 30%-40%, halophilic halometa 45%-55%, halophilic lactobacillus plantarum 5%-15%, and halophilic brewer's yeast 2%-8%.

[0020] Bacillus amyloliquefaciens is used to dominate the synthesis of extracellular polysaccharides and the decomposition of organic matter; halophilic halometa is used to actively excrete sodium and balance the salt concentration in the environment; halophilic lactobacillus is used to produce acid to regulate pH and inhibit other bacteria; and halophilic brewer's yeast is used to regulate osmotic pressure and mask salinity.

[0021] The salt tolerance limits for each microbial species in the compound microbial agent are as follows: Bacillus amyloliquefaciens ≥10% NaCl, halophilic halometa ≥15% NaCl, halophilic Lactobacillus plantarum ≥12% NaCl, and halophilic Saccharomyces cerevisiae ≥14% NaCl. The compound microbial agent can fully adapt to the high-salt environment of kimchi tails (above 14%); and each species has a clear functional division: Bacillus amyloliquefaciens dominates the synthesis of extracellular polysaccharides (EPS) and the decomposition of organic matter; halophilic halometa ≥15% NaCl; halophilic Lactobacillus plantarum produces acid to adjust pH and suppress other bacteria; and halophilic Saccharomyces cerevisiae regulates osmotic pressure, laying the foundation for subsequent efficient metabolism. Step 3: Segmented fermentation. The first stage, from 0 to 72 hours, is the acid production and sodium excretion period. The temperature is controlled at 30±2℃ and the humidity at 60%±5%, with the pile turned every 12 hours. Under the temperature and humidity conditions of the first stage, the optimal acid production temperature for halophilic lactobacillus is met. It can produce lactic acid, which combines with Na⁺ to form sodium lactate. At the same time, the pH of the environment is lowered to below 4.5, effectively inhibiting the growth of other bacteria. Turning the pile ensures uniform aeration of the material, allowing Bacillus amyloliquefaciens to fully decompose organic matter such as cellulose and release soluble carbon sources, providing energy for halophilic halometabolites to initiate active sodium excretion. The three factors work together to achieve efficient acid production and sodium excretion, solving the problems of contamination by other bacteria and low initial metabolic efficiency in conventional fermentation. The second stage, lasting 72-120 hours, is the desalination-flocculation period. The temperature is raised to 45±3℃, humidity to 55%±5%, and 10% by mass of corn stalk powder is added. A breathable membrane is used to control the oxygen concentration to <2%. Raising the temperature to 45±3℃ in this second stage enhances the ability of Bacillus amyloliquefaciens to secrete EPS, which can encapsulate Na⁺ to form flocs. Corn stalk powder adjusts the carbon-to-nitrogen ratio and enhances the material's looseness. Combined with oxygen concentration control (anaerobic microzone), this allows salt-tolerant brewer's yeast to produce 10-15 g / L glycerol to regulate osmotic pressure, alleviating the continuous inhibition of the bacteria by high salt levels. Simultaneously, salt-tolerant Haloxylon ammodendron enhances active sodium excretion through Na⁺ / H⁺ reverse transporters. These three factors work synergistically to complete deep desalination and flocculation, providing favorable conditions for subsequent solid-liquid separation and desalination. In the first stage of the three-stage fermentation process, Bacillus amyloliquefaciens, halophilic Lactobacillus plantarum, and halophilic Halomonas work together to produce acid and excrete sodium. In the second stage, Bacillus amyloliquefaciens, halophilic Halomonas, and halophilic Saccharomyces cerevisiae work synergistically to complete desalination and flocculation.

[0022] The key points of staged fermentation are shown in the table below: stage Time (h) Temperature (°C) humidity(%) Key points of operation Microbial dominant function Phase 1 (Acid production - Sodium excretion) 0-72 30±2 60±5 <![CDATA[Inoculate with a composite strain at 3% of the dry weight of the tail vegetables, with the total bacterial count ≥ 1.5×10 9 CFU / g, and turn the pile once every 12 hours with a turning depth of 30 cm]]> Amylolyticus decomposes cellulose to produce sugar, while halophilic Lactobacillus plantarum produces lactic acid to adjust the pH to 4.0-4.5. Haloxymonas hydrophila then initiates sodium excretion. Second stage (desalination-flocculation period) 72-120 45±3 55±5 Add 10% corn stalk powder by weight, crush to a particle size ≤2mm, adjust the moisture content to 55%±2%, cover with a breathable membrane to control oxygen concentration <2% (anaerobic microzone). Bacillus amyloliquefaciens secretes EPS to encapsulate Na⁺+, while salt-tolerant halometabolites enhance sodium excretion, and salt-tolerant Saccharomyces cerevisiae produces glycerol to regulate osmotic pressure. Step Four: Solid-Liquid Separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the solids using a screw press until the moisture content reaches 45-50%. This solid-liquid separation efficiently removes the filtrate containing free salts, facilitating subsequent centralized processing, while ensuring the solid material retains appropriate moisture levels, providing optimal humidity conditions for secondary fermentation. This avoids the problems of high salt residue or excessively dry material encountered in conventional separation methods. In Step Four, a screw press with a 0.3mm orifice is used to ensure that the moisture content of the separated solid material is reduced to 45-50%.

[0023] Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, followed by aging in an aging tank until the moisture content is ≤30%; aerobic fermentation at 50-60℃ for 5 hours can achieve rapid maturation of the material, while avoiding prolonged high temperature damage to organic matter; during the aging process, the pile is turned over every 48 hours to promote heat dissipation and moisture evaporation, so that the material temperature gradually approaches the room temperature and the moisture content drops below 30%, obtaining a low-salt organic fertilizer semi-finished product, solving the problem of incomplete maturation or organic matter loss in conventional fermentation; In step five, during the secondary fermentation, the solid material is transferred to a constant temperature aerobic fermentation machine and fermented at 50-60℃ for 5 hours to avoid high temperature damaging the organic matter. Then it is transferred to an aging tank and turned over every 48 hours until the material temperature is close to the room temperature and the moisture content drops below 30%, thus obtaining a low-salt organic fertilizer semi-finished product.

[0024] Step Six: Quality Control and Packaging: Test and adjust the final product's Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium (NPK) content. Seal the product in moisture-proof composite bags. In Step Six, if the Cl⁻ content is >3%, add 5% humic acid to adjust nutrients and complex Cl⁻; if the pH value is <5.5, add 1% lime powder to neutralize the acidity. During Step Six's quality control, the testing indicators are: Cl⁻ content ≤3%, organic matter ≥30%, pH value 5.5-7.5, and total NPK ≥4%.

[0025] Further targeted adjustments are made: if the Cl⁻ content is >3%, 5% humic acid is added, which can both chelate Cl⁻ to reduce salt content and regulate nutrients; if the pH value is <5.5, 1% lime powder is added to neutralize the acidity. After adjustment, the product is sealed in moisture-proof composite bags to ensure stable product quality. This step ensures that the final product fully meets the NY525-2021 "Organic Fertilizer" standard, solving the problem of non-compliance with product indicators and inability to utilize resources in conventional technologies.

[0026] The composite microbial strains in this invention exhibit strong functional synergy: through the division of labor and cooperation of Bacillus amyloliquefaciens leading the synthesis of extracellular polysaccharides (EPS), halophilic halometabolites actively excreting sodium, halophilic Lactobacillus plantarum producing acid to suppress other bacteria, and halophilic Saccharomyces cerevisiae regulating osmotic pressure, efficient desalination and organic matter degradation are achieved under high-salt conditions, with a Cl⁻ reduction rate >60%. The process parameters were optimized in stages. The temperature, humidity and turning of the first stage (30℃ for acid production and sodium removal) and the second stage (45℃ for desalination and flocculation) were controlled to match the microbial metabolic patterns and improve efficiency. The carrier adsorbed zeolite and biochar to reduce the initial salt load and avoid high salt inhibition. The product meets the standards, with the final organic fertilizer semi-finished product having an organic matter content of ≥30%, Cl⁻≤3%, total nitrogen, phosphorus and potassium content of ≥4%, and pH of 5.5-8.5, fully meeting the requirements of NY525-2021 organic fertilizer.

[0027] Example 2: The present invention provides the following technical solution: a method for resource utilization of kimchi waste to prepare organic fertilizer, comprising the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, and add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, and pile for 2 hours; Step 2: Inoculate with compound microbial strain at 3% of the dry weight of the vegetable tails, with a total bacterial count ≥1.5×10⁹ CFU / g; Step 3: Segmented fermentation. The first stage (0-72 hours) is the acid production and sodium excretion period, with the temperature controlled at 30±2℃ and humidity at 60%±5%, and the pile turned over every 12 hours. The second stage (72-120 hours) is the desalination and flocculation period, with the temperature increased to 45±3℃ and humidity at 55%±5%. 10% corn stalk powder is added by mass, and the pile is covered with a breathable membrane to control the oxygen concentration to <2%. Step 4: Solid-liquid separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the mixture using a screw press until the moisture content reaches 45-50%. Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, then transfer to an aging tank to age until the moisture content is ≤30%; Step Six: Quality Control and Packaging: Test and adjust the Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium content of the final product, and seal it in a moisture-proof composite bag.

[0028] In this embodiment, everything else is the same as in Embodiment 1, except that the compound strain includes the following components in the following mass ratio: Bacillus amyloliquefaciens 35%, halophilic halophilus 50%, halophilic lactobacillus plantarum 10%, and halophilic brewer's yeast 5%.

[0029] Example 3: The present invention provides the following technical solution: a method for resource utilization of kimchi waste to prepare organic fertilizer, comprising the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, and add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, and pile for 2 hours; Step 2: Inoculate with compound microbial strain at 3% of the dry weight of the vegetable tails, with a total bacterial count ≥1.5×10⁹ CFU / g; Step 3: Segmented fermentation. The first stage (0-72 hours) is the acid production and sodium excretion period, with the temperature controlled at 30±2℃ and humidity at 60%±5%, and the pile turned over every 12 hours. The second stage (72-120 hours) is the desalination and flocculation period, with the temperature increased to 45±3℃ and humidity at 55%±5%. 10% corn stalk powder is added by mass, and the pile is covered with a breathable membrane to control the oxygen concentration to <2%. Step 4: Solid-liquid separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the mixture using a screw press until the moisture content reaches 45-50%. Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, then transfer to an aging tank to age until the moisture content is ≤30%; Step Six: Quality Control and Packaging: Test and adjust the Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium content of the final product, and seal it in a moisture-proof composite bag.

[0030] In this embodiment, everything else is the same as in Embodiment 1, except that the compound strain includes the following components in the following mass ratio: Bacillus amyloliquefaciens 40%, halophilic halometa 45%, halophilic lactobacillus plantarum 10%, and halophilic brewer's yeast 5%.

[0031] Example 4: The present invention provides the following technical solution: a method for resource utilization of kimchi waste to prepare organic fertilizer, comprising the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, and add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, and pile for 2 hours; Step 2: Inoculate with compound microbial strain at 3% of the dry weight of the vegetable tails, with a total bacterial count ≥1.5×10⁹ CFU / g; Step 3: Segmented fermentation. The first stage (0-72 hours) is the acid production and sodium excretion period, with the temperature controlled at 30±2℃ and humidity at 60%±5%, and the pile turned over every 12 hours. The second stage (72-120 hours) is the desalination and flocculation period, with the temperature increased to 45±3℃ and humidity at 55%±5%. 10% corn stalk powder is added by mass, and the pile is covered with a breathable membrane to control the oxygen concentration to <2%. Step 4: Solid-liquid separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the mixture using a screw press until the moisture content reaches 45-50%. Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, then transfer to an aging tank to age until the moisture content is ≤30%; Step Six: Quality Control and Packaging: Test and adjust the Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium content of the final product, and seal it in a moisture-proof composite bag.

[0032] In this embodiment, everything else is the same as in the previous embodiment, except that the compound strain includes the following components in the following mass ratio: Bacillus amyloliquefaciens 30%, halophilic halophilus 55%, halophilic lactobacillus plantarum 10%, and halophilic brewer's yeast 5%.

[0033] Example 5: In this example, to further verify the superiority of the technical solution of the present invention, an experiment was set up to verify the treatment effect of different compound bacterial strain ratios, and existing conventional technology was used as a comparative example.

[0034] The experimental testing standards are as follows: Cl⁻ reduction rate: The Cl⁻ content in kimchi tails before and after treatment was detected using the method specified in GB / T 15687-2008 "Determination of Chloride Ion Content in Feed". The reduction rate was calculated as: (Cl⁻ content before treatment - Cl⁻ content after treatment) / Cl⁻ content before treatment × 100%; Organic matter degradation rate: The organic matter content before and after treatment was determined by potassium dichromate titration method. The degradation rate was calculated as follows: (Organic matter content before treatment - Organic matter content after treatment) / Organic matter content before treatment × 100%. Product quality indicators: Organic matter content, total nitrogen, phosphorus and potassium nutrients and pH value are tested according to NY525-2021 "Organic Fertilizer" standard; Fermentation cycle: Record the time from inoculation of the microbial strain to the product reaching the maturity standard (stable temperature, no foul odor).

[0035] Experimental materials: The kimchi tails used in the experiment were uniformly obtained from a kimchi processing plant. The initial test indicators were: Cl⁻ content 14.2%, organic matter content 72.5%, and moisture content 78%. A total of 3 examples (Example 2, Example 3, and Example 4) and 1 comparative example were set up. The weight of the tails in each group was 10 kg, and the experiment was repeated 3 times and the average value was taken.

[0036] Comparative example (existing conventional microbial fermentation technology) Commonly used bacterial strains: Bacillus subtilis (common type); salt tolerance limit 4.5% NaCl; inoculum size 3% (dry weight of vegetable waste); total bacterial count 1.5 × 10⁻⁶. 9 CFU / g; Fermentation process: constant temperature 35℃, humidity 60%, turn over once every 24 hours, no pretreatment adsorption and desalination steps, the rest of crushing, solid-liquid separation, and secondary fermentation are the same as in Example 1.

[0037] The experimental results are shown in the table below: Group Cl⁻ reduction rate (%) Organic matter degradation rate (%) Fermentation cycle (days) Organic matter content (%) of the product Total nitrogen, phosphorus, and potassium nutrients in the product (%) Product pH value Does it comply with NY525-2021 standard? Comparative Example 27.8 37.6 8 28.5 3.2 7.8 no Example 2 65.4 68.2 5 35.6 4.5 6.2 yes Example 3 63.1 70.5 5 36.2 4.6 6.0 yes Example 4 67.8 66.3 5 34.8 4.4 6.3 yes Analyze the results based on the table above. Desalination effect: The Cl⁻ reduction rate of the three examples all exceeded 63%, which was much higher than the 27.8% of the comparative example. Among them, Example 4 had the best desalination effect because it had the highest proportion of salt-tolerant Haloxylon ammodendron. This proves that the active sodium excretion function of the salt-tolerant Haloxylon ammodendron in the compound strain of the present invention and the pretreatment adsorption work synergistically to effectively solve the problem of low desalination efficiency caused by high salt inhibition in the prior art. Organic matter degradation and fermentation cycle: In the examples, the organic matter degradation rate exceeded 66%, and the fermentation cycle was only 5 days; while in the comparative example, the degradation rate was less than 40%, and the fermentation cycle was as long as 8 days. In Example 3, because Bacillus amyloliquefaciens had the highest proportion, the organic matter degradation rate was the best, indicating that the organic matter decomposition function dominated by Bacillus amyloliquefaciens matched the segmented fermentation process, which greatly improved the degradation efficiency and shortened the cycle, solving the problems of slow degradation and long cycle of conventional technologies.

[0038] Product Quality: The products of the three examples all meet the NY525-2021 standard, with an organic matter content of ≥34.8% and a total nitrogen, phosphorus and potassium content of ≥4.4%. The comparative example did not meet the standard due to insufficient degradation, insufficient organic matter and nutrient content, and a high pH value. This proves that the present invention can realize the standardized preparation of organic fertilizer and solves the problem that existing technology products cannot be recycled because they do not meet the standards.

[0039] In summary, the embodiments of the present invention with different ratios of compound microbial strains are all superior to existing conventional technologies, and can be adapted to different desalination or degradation requirements by adjusting the ratio of microbial strains, thus demonstrating strong practicality.

[0040] Testing showed that the final product of this embodiment had a Cl⁻ reduction rate of >60%, an organic matter content of ≥30%, a total nitrogen, phosphorus and potassium content of ≥4%, and a pH value of 5.5-7.5, fully complying with the NY525-2021 standard, which fully demonstrates that this method can achieve efficient resource utilization of kimchi waste.

[0041] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A method for resource-based utilization of kimchi waste to prepare organic fertilizer, characterized in that: Includes the following steps: Step 1: Pretreatment: Crush the kimchi tails to a particle size ≤5mm, adjust the moisture content to 60%±2% using a screw press, add 2% zeolite and 3% biochar by mass for adsorption and desalination treatment, and pile for 2 hours; Step 2: Inoculate with compound microbial strains at 3% of the dry weight of the vegetable waste, with a total microbial count ≥ 1.5 × 10⁻⁶. 9 CFU / g; Step 3: Segmented fermentation. The first stage (0-72 hours) is the acid production and sodium excretion period, with the temperature controlled at 30±2℃ and humidity at 60%±5%, and the pile turned over every 12 hours. The second stage (72-120 hours) is the desalination and flocculation period, with the temperature increased to 45±3℃ and humidity at 55%±5%. 10% corn stalk powder is added by mass, and the pile is covered with a breathable membrane to control the oxygen concentration to <2%. Step 4: Solid-liquid separation. After 120 hours of fermentation, solid-liquid separation is performed by pressing the mixture using a screw press until the moisture content reaches 45-50%. Step 5: Secondary fermentation, aerobic fermentation at 50-60℃ for 5 hours, then transfer to an aging tank to age until the moisture content is ≤30%; Step Six: Quality Control and Packaging: Test and adjust the Cl⁻ content, organic matter, pH value, and total nitrogen, phosphorus, and potassium content of the final product, and seal it in a moisture-proof composite bag.

2. The method for preparing organic fertilizer from kimchi waste according to claim 1, characterized in that: The compound microbial strain comprises the following components in the following mass ratios: Bacillus amyloliquefaciens 30%-40%, halophilic halometa 45%-55%, halophilic lactobacillus plantarum 5%-15%, and halophilic brewer's yeast 2%-8%.

3. The method for preparing organic fertilizer from kimchi waste according to claim 1, characterized in that: In the first pretreatment step, the zeolite has an adsorption capacity of 0.5 mmol / g and is used to adsorb Na ions from kimchi tails.

4. The method for preparing organic fertilizer by utilizing kimchi waste as described in claim 2, characterized in that: In the first stage of the three-stage fermentation process, Bacillus amyloliquefaciens, halophilic Lactobacillus plantarum, and halophilic Halomonas work together to produce acid and excrete sodium. In the second stage, Bacillus amyloliquefaciens, halophilic Halomonas, and halophilic Saccharomyces cerevisiae work synergistically to complete desalination and flocculation.

5. The method for preparing organic fertilizer by utilizing kimchi waste according to claim 1, characterized in that: In step four, the solid-liquid separation process, a screw press with an aperture of 0.3 mm is used to ensure that the moisture content of the separated solid material is reduced to 45-50%.

6. The method for preparing organic fertilizer from kimchi waste according to claim 1, characterized in that: In step five, during the secondary fermentation, the solid material is transferred to a constant temperature aerobic fermentation machine and fermented at 50-60℃ for 5 hours to avoid high temperature damaging the organic matter. Then it is transferred to an aging tank and turned over every 48 hours until the material temperature is close to the room temperature and the moisture content drops below 30%, thus obtaining a low-salt organic fertilizer semi-finished product.

7. The method for preparing organic fertilizer from kimchi waste according to claim 1, characterized in that: In step six, quality control and packaging, if the Cl⁻ content is detected to be >3%, 5% humic acid is added to adjust nutrients and complex Cl⁻; if the pH value is <5.5, 1% lime powder is added to neutralize the acidity.

8. The method for preparing organic fertilizer from kimchi waste according to claim 7, characterized in that: In step six, during quality control, the testing indicators are: Cl⁻ content ≤3%, organic matter ≥30%, pH value 5.5-7.5, and total nitrogen, phosphorus, and potassium ≥4%.

9. A method for preparing organic fertilizer from kimchi waste according to claim 2, characterized in that: Bacillus amyloliquefaciens is used to dominate the synthesis of extracellular polysaccharides and the decomposition of organic matter; halophilic halometa is used to actively excrete sodium and balance the salt concentration in the environment; halophilic lactobacillus is used to produce acid to regulate pH and inhibit other bacteria; and halophilic brewer's yeast is used to regulate osmotic pressure and mask salinity.

10. A method for preparing organic fertilizer from kimchi waste according to claim 9, characterized in that: The salt tolerance limits for each bacterial species in the compound microbial agent are as follows: Bacillus amyloliquefaciens ≥10% NaCl, salt-tolerant Halomonas ≥15% NaCl, salt-tolerant Lactobacillus plantarum ≥12% NaCl, and salt-tolerant Saccharomyces cerevisiae ≥14% NaCl.

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