A method of composting organic waste with reduced loss of nitrogen

Abstract

The application discloses a kind of organic waste composting methods for reducing nitrogen loss, belong to the technical field of organic waste resource utilization, in different stages of organic waste fermentation, calcium peroxide is added, on the one hand, can maintain the oxygen environment of heap system, inhibit denitrification;On the other hand, by regulating the pH environment in system, reduce ammonia volatilization.This double synergistic effect, continue to increase efficiency in the whole composting fermentation process, oxygen regulation breaks down the gaseous nitrogen loss caused by denitrification from the root, pH regulation effectively inhibits free ammonia volatilization, the two effects cooperate with each other, throughout the whole process, can realize the efficient nitrogen conservation of organic waste raw materials from fermentation start to stable decomposition, effectively solve the problems that existing nitrogen conservation technology is not good, cost is high, easy to cause secondary pollution and affect composting maturity etc..

Description

Technical Field

[0001] This invention belongs to the technical field of organic waste resource utilization, specifically relating to a method for composting organic waste to reduce nitrogen loss. Background Technology

[0002] Composting is an important way to realize the resource utilization of organic waste. Through the metabolic action of microorganisms, organic waste is transformed into nutrient-rich organic fertilizer. This process not only reduces the volume and renders organic waste harmless, but also provides high-quality organic fertilizer for agricultural production, aligning with the concept of green and sustainable development. Nitrogen, as an essential macronutrient for plant growth, is one of the core indicators for evaluating the quality of compost products. However, in traditional composting processes, nitrogen loss is extremely serious, typically reaching 30% to 60%. This not only reduces the nutrient value and market competitiveness of compost products but also triggers a series of environmental problems related to the emission of nitrogen compounds and nitrogen oxides. Nitrogen loss mainly occurs in the following three key processes: 1. Ammonia volatilization: During composting, microorganisms decompose nitrogen-containing organic matter (such as protein, urea, etc.) to produce ammonium nitrogen. When the compost is under alkaline conditions (pH>8.5), ammonium nitrogen is easily converted into ammonia and volatilized into the atmosphere. This is the main pathway for nitrogen loss in traditional composting, accounting for 50% to 70% of the total nitrogen loss; 2. Denitrification: Under the local anaerobic environment of the compost, denitrifying bacteria will convert nitrate nitrogen into gaseous nitrogen compounds such as nitrogen gas and nitrous oxide and release them into the atmosphere. Especially in the later stages of composting when ventilation is insufficient and the temperature of the compost decreases, nitrogen loss caused by denitrification can account for 20% to 30%; 3. Leaching loss: Soluble nitrogen (such as ammonium nitrogen and nitrate nitrogen) produced during composting will be lost with rainwater or leachate from the compost. After entering the soil and water bodies, it may cause soil salinization and water eutrophication, which will harm the ecological environment.

[0003] Currently, adding conditioners is one of the mainstream technologies for nitrogen retention in composting. Regarding chemical conditioners, acidic conditioners such as superphosphate (e.g., invention patent CN202511158170.7) can only inhibit ammonia volatilization by lowering the compost pH, and their effect on inhibiting denitrification (the loss of nitrate nitrogen in the form of N2O and N2) is very limited. Furthermore, long-term use can easily lead to excessively low pH in the compost pile, which is detrimental to the microbial process of promoting decomposition. Moreover, such acidic conditioners cannot create a suitable metabolic environment for aerobic microorganisms. Furthermore, while metal salts such as magnesium salts and modified red mud (e.g., invention patent CN118255617B) can form compounds like struvite with ammonium nitrogen and phosphate to fix nitrogen, their effect on inhibiting nitrate nitrogen denitrification and reducing nitrogen loss is very limited. Simultaneously, the nitrogen retention effect of these salt-based conditioners is greatly affected by fluctuations in composting temperature, humidity, and pH. In composting environments with significant temperature, humidity, or pH changes, they are easily deactivated due to instability, which also significantly weakens their role in promoting composting humification. Besides chemical conditioners, in the application of physical adsorption conditioners, materials such as zeolite and biochar (e.g., invention patent application CN202510304868.9), although capable of passively capturing volatile nitrogen oxides such as ammonia or nitrate nitrogen through physical adsorption, cannot inhibit nitrogen loss from key oxygen-related processes such as nitrification and denitrification. Moreover, these adsorbent materials are easily saturated, requiring frequent replacement or regeneration, significantly increasing the operating costs of composting. Furthermore, these adsorbent materials do not regulate key environmental factors such as oxygen supply and pH in composting, making it difficult to achieve stable nitrogen retention over the long term. Process control technologies mainly involve carbon-to-nitrogen ratios, ventilation, membrane covering, and biological agents. Adjusting the carbon-to-nitrogen ratio relies on frequent monitoring of the dynamic changes in the carbon and nitrogen content of the compost material and precise addition of carbon sources such as sawdust and straw, making the process extremely complex and time-consuming. Forced high-volume ventilation requires continuous consumption of large amounts of electricity, resulting in high energy costs for large-scale composting, and the precise control of ventilation volume is a high technical barrier. Membrane covering composting technology uses physical barriers, which, while blocking ammonia volatilization, cannot effectively intervene in the denitrification process inside the compost, leaving the root cause of nitrogen loss unresolved. Biological agents, such as ammonia-tolerant strains and compound agents, rely on microbial metabolism to retain nitrogen, but their effectiveness is highly susceptible to fluctuations in compost temperature and humidity. For example, during high-temperature composting, the activity of most microorganisms decreases significantly, leading to highly unstable nitrogen retention. In addition, biological agents require customized cultivation, which is not only costly but also very complex to operate, making it difficult to apply widely in large-scale composting production.

[0004] In summary, existing technologies suffer from limited nitrogen retention, high operating costs, and the potential to cause secondary pollution. Therefore, developing a simple, low-cost composting method with significant nitrogen retention is a pressing technical challenge in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for composting organic waste to reduce nitrogen loss in order to solve the problems mentioned in the background art or achieve better technical effects.

[0006] To solve the aforementioned technical problems, the inventors derived the technical solution of this invention through practice and summarization. This invention discloses a method for composting organic waste to reduce nitrogen loss. Calcium peroxide is added during the four stages of organic waste composting: the heating period, the high-temperature period, the cooling period, and the maturation period. This maintains the aerobic environment of the composting system, inhibits denitrification, and reduces the volatilization of free ammonia by regulating the pH of the composting system.

[0007] Furthermore, during the heating period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; during the high-temperature period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; during the cooling period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; and during the maturation period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost.

[0008] Furthermore, the calcium peroxide has a purity of ≥50% and a particle size of 150~200 mesh.

[0009] Furthermore, the organic waste is selected from one or more mixtures of livestock and poultry manure, crop straw, and kitchen waste; the carbon-to-nitrogen ratio in the organic waste is 25-30:1.

[0010] Furthermore, any of the above-described methods for composting organic waste to reduce nitrogen loss includes the following steps:

[0011] S1: Select organic waste as composting raw material, then pre-treat it, mix it thoroughly, and use a mixer or manual turning to ensure that the material is mixed evenly;

[0012] S2: Fill the material obtained in S1 into a sealed fermentation tank, add calcium peroxide during the heating period, high temperature period, cooling period and decomposition period and pile it up evenly. Turn it over every 2 to 3 days during the fermentation process until decomposition is complete.

[0013] During the heating period, the amount of calcium peroxide added is 1% of the total dry weight of the compost;

[0014] During the high-temperature period, the amount of calcium peroxide added is 0.1% to 5% of the total dry weight of the compost.

[0015] During the cooling period, the amount of calcium peroxide added is 1% of the total dry weight of the compost;

[0016] During the composting period, the amount of calcium peroxide added is 1% of the total dry weight of the compost.

[0017] S3: The compost that has been fully decomposed in S2 is judged by indicators. When the compost meets the standards, it is judged that the compost is fully decomposed, fermentation is stopped, the pile enters the natural aging stage, the fermentation process terminates on its own, and the decomposed compost product is obtained. When the compost does not meet the standards, it is returned to S2 to continue fermentation, and the indicators are tested again.

[0018] Furthermore, in S1, the pretreatment method is as follows: impurities in the material are removed by manual screening or mechanical sorting, and then the material is crushed to a particle size of 2~5cm.

[0019] Furthermore, in S2, the method for uniformly turning over the material is as follows: During operation, the tank is briefly opened, and manual operation is used to perform layered and zoned, top-to-bottom replacement and radial displacement turning operations on the material in the sealed fermentation tank. Long-handled tools are used to loosen the material from top to bottom and break up clumps, turning the material deposited at the bottom of the tank to the surface, and replacing the surface material with the middle and lower parts. At the same time, diagonal displacement and internal and external exchange are carried out along the circumference and radial direction of the tank, so that the material can achieve full convection and mixing in both the vertical and horizontal directions. The material is kept in a loose state throughout the process, avoiding trampling and compaction, eliminating dead corners and stratification in the tank, and achieving uniform material turning and consistent aeration in a sealed environment to ensure a stable and uniform fermentation process. After the stirring and turning are completed, the tank is quickly closed to avoid disturbance of the fermentation environment inside the tank and gas leakage and temperature fluctuations.

[0020] Furthermore, in S3, the indicators for determining compost maturity include temperature, pH, and C / N ratio.

[0021] The temperature index is determined as follows: the lid is opened at a set time each day, and a temperature measuring device is directly inserted into the upper, middle, and lower layers of the pile to measure the temperature. Each time the temperature is measured, ensure that the probe of the temperature measuring device is fully inserted into the pile and in full contact with the material. Record the temperature data after the reading stabilizes. After the temperature measurement is completed, the lid is closed quickly to reduce disturbance to the fermentation environment inside the tank and prevent gas leakage and temperature fluctuations. Measure continuously for 5 to 7 days. If the temperature of the pile measured each day drops to the ambient temperature and there is no obvious temperature rebound, the temperature index can be determined to meet the standard.

[0022] The pH index was determined as follows: samples were collected from the upper, middle and lower layers of the fermenter using a sealed sampler through the pre-set sealed sampling port. The sampler was then sealed immediately after sampling. The sample was mixed with ultrapure water in a certain proportion, stirred and allowed to stand. The pH value of the supernatant was measured using a pH meter with an accuracy of ≥0.01. The pH value was considered complete if it remained stable between 6.5 and 8.0 after three consecutive sampling measurements.

[0023] The determination of the C / N ratio index is as follows: a mixed sample of the stockpile is collected in different areas of the tank through a closed sampling method; after the sample is dried and crushed, the organic carbon content is determined by potassium dichromate oxidation-external heating method, and the total nitrogen content is determined by Kjeldahl method. The ratio of the two is the C / N ratio; if the ratio is stable at 15~20:1 for two consecutive sampling measurements, the determination is completed.

[0024] Furthermore, in S2, after the material is filled into the sealed fermentation tank, calcium peroxide particles or slow-release calcium peroxide particles can be added in stages.

[0025] The particle size of the calcium peroxide particles is controlled at 1~3mm; the slow-release calcium peroxide particles are prepared by using calcium peroxide particles as the core material and cellulose as the coating material: first, cellulose is coated on the surface of the calcium peroxide particles to form a core-shell structure, wherein the mass ratio of calcium peroxide particles in the slow-release particles is strictly controlled at 60%~65%, and then granulated by a granulator to finally produce calcium peroxide slow-release particles with a particle size of 2.5mm~3mm.

[0026] Furthermore, in step S2, calcium peroxide and a small amount of auxiliary nitrogen-retaining agent are added simultaneously at each stage when the material is filled into the sealed fermentation tank; the auxiliary nitrogen-retaining agent is bentonite, and the amount added is 1 to 2% of the dry weight of the pile.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) This invention solves the technical problems of severe nitrogen loss, long fermentation cycle, inaccurate maturity judgment and low calcium peroxide utilization efficiency in the existing composting process by designing a complete composting process. It also combines a precise control method of adding calcium peroxide in stages to achieve efficient nitrogen retention and rapid maturity of organic waste composting, while ensuring stable quality of compost products.

[0029] (2) In the four cycles of composting—heating period, high temperature period, cooling period, and maturation period—calcium peroxide is added to the compost in stages and in controlled amounts according to the temperature, oxygen content, microbial activity, and nitrogen loss pattern of the compost in each cycle. By controlling the dosage, timing, and method of adding calcium peroxide in each cycle, nitrogen preservation is achieved throughout the composting cycle, while ensuring the maturity of the compost and reducing nitrogen preservation costs.

[0030] (3) The present invention adds calcium peroxide at different stages of organic waste fermentation. On the one hand, it can maintain the oxygen environment of the compost system and inhibit denitrification; on the other hand, it can reduce ammonia volatilization by regulating the pH environment of the system. This dual synergistic effect is continuously enhanced throughout the entire composting fermentation process. Oxygen supply regulation blocks the loss of gaseous nitrogen caused by denitrification from the source, and pH regulation effectively inhibits the volatilization of free ammonia. The two effects work together and run through the whole process, which can achieve efficient nitrogen retention of organic waste raw materials from fermentation start-up to stable composting. It effectively solves the problems of poor effect, high cost, easy secondary pollution and impact on composting maturity of existing nitrogen retention technologies.

[0031] (4) Compared with the traditional process, which involves adding calcium peroxide all at once in the early stage of composting fermentation, the segmented addition process adopted in this invention can significantly improve the nitrogen utilization efficiency and compost product stability during the composting process, and has significant environmental benefits and economic value. This invention achieves full-cycle dynamic regulation of the compost microenvironment by adding calcium peroxide in stages during the heating, cooling and maturation periods. First, this strategy avoids the risk of local over-alkaliness and maintains the pH value of the system stable in the optimal activity range of 7.0~8.5, ensuring the continuous and efficient metabolism of the microbial community; second, calcium peroxide slowly releases oxygen throughout the fermentation cycle, constructing and maintaining a high oxygen partial pressure environment, fundamentally inhibiting the expression and activity of key denitrification enzymes, and effectively blocking nitrogen denitrification loss; finally, the continuous slightly alkaline environment and the effect of calcium ions promote the condensation polymerization of humic acid and the solid-phase stability of nitrogen, significantly improving the total nitrogen retention rate and humification degree of the compost product. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the closed fermentation tank used in this invention;

[0033] Figure 2 This is a process flow diagram of the organic waste composting method for reducing nitrogen loss according to the present invention;

[0034] Figure label:

[0035] 1. Sealing cap;

[0036] 2. Ventilation tube;

[0037] 3. Tank body;

[0038] 4. Filter screen;

[0039] 5. Air pump. Detailed Implementation

[0040] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0041] Unless otherwise specified, the raw materials or equipment used in the following embodiments are all commercially available products.

[0042] The temperature measuring device used in this invention is a thermometer or a temperature sensor.

[0043] The four stages of composting in this invention are four consecutive stages divided according to temperature and microbial activity during the composting process, namely the heating period, high temperature period, cooling period, and maturation period. The nitrogen conversion pathway and nitrogen loss form are significantly different in each stage, which is the core basis for the segmented addition of calcium peroxide in this invention.

[0044] The warming period is the stage after composting starts, when the temperature of the compost pile rises from the ambient temperature to below 500℃. The core characteristics are the gradual increase in microbial activity, the initiation of ammonification, low oxygen content in the compost pile, easy occurrence of local anaerobic conditions, and nitrogen loss mainly in the form of ammonia volatilization.

[0045] High-temperature period: The stage in which the pile temperature is maintained at 50℃ and above. The core characteristics are that the activity of thermophilic microorganisms reaches its peak, the oxygen consumption rate is fast, and anaerobic micro-zones are easily formed. The main form of nitrogen loss is the denitrification of nitrate nitrogen caused by denitrification, while a small amount of ammonia volatilization still occurs.

[0046] Cooling period: The stage in which the pile temperature drops from 50℃ to ambient temperature. The core characteristics are: decreased activity of thermophilic microorganisms, gradual recovery of mesophilic microorganisms, decline in pile oxygen content, slow and continuous denitrification, suppressed nitrification, and a small amount of nitrogen loss.

[0047] Maturation stage: The stage in which the temperature of the pile stabilizes at the ambient temperature. The core characteristic is that the activity of microorganisms tends to stabilize, the pile gradually matures, the oxygen demand decreases, and a weakly aerobic environment needs to be maintained to ensure the completion of nitrification and avoid continuous nitrogen loss. At the same time, it is necessary to prevent additive residues from affecting the degree of maturity.

[0048] The closed fermentation tank used in the closed fermentation stage of this invention is as follows: Figure 1 As shown, it includes a tank body 3, which is the core body of the sealed fermentation tank. It is used to contain compost materials and provide fermentation space. The tank body is cylindrical in shape and the inner wall is treated with anti-corrosion to prevent the materials from corroding the tank body and to avoid the tank body material from affecting the compost quality.

[0049] The top of the tank 3 is equipped with a sealing cover 1. The function of the sealing cover 1 is to seal the tank and prevent ammonia nitrogen volatilization, odor leakage and excessive entry of outside air during fermentation. The sealing cover 1 is made of carbon steel and has the same diameter as the tank 3. A vent is provided in the middle of the sealing cover 1. The vent is equipped with a vent pipe 2 to facilitate ventilation inside the tank 3.

[0050] The ventilation pipe 2 is divided into a ventilation pipe at the bottom of the tank and a ventilation pipe on the sealing cover. Together, they form the core of the internal air path regulation of the tank 3, which is adapted to the dual requirements of nitrogen retention by calcium peroxide and aerobic fermentation. The ventilation pipe at the bottom of the tank is rigidly connected to the ventilation pump 5. The pipe body is evenly opened with air distribution holes, which can evenly distribute the pumped air to the material layer at the bottom of the tank. The ventilation pipe on the cover serves as an exhaust and auxiliary oxygenation channel, which can promptly discharge waste gases such as carbon dioxide produced by microbial metabolism and calcium peroxide decomposition, thereby maintaining the air pressure balance inside the tank 3.

[0051] The bottom of the tank 3 is lined with a filter screen 4, which is a key component for the protection of the aeration system and the stability of the fermentation environment, directly serving the nitrogen retention process requirements. Its core function is to effectively separate the compost solids from the fermentation leachate, preventing solid impurities such as straw and manure from entering the bottom aeration pipe and air pump, preventing blockage of pipes and equipment, ensuring the smooth oxygen supply of the aeration pump and the air distribution of the aeration pipe, and allowing the leachate produced during fermentation to seep down smoothly, preventing water accumulation in the tank from forming a local anaerobic environment, preventing the large-scale proliferation of denitrifying bacteria from aggravating nitrogen loss, indirectly ensuring the nitrogen retention effect of calcium peroxide, and maintaining the stability of the overall aerobic fermentation environment in the tank.

[0052] The aeration pump, serving as the active oxygen supply device for aerobic fermentation within the tank, is rigidly connected to the aeration pipe at the bottom of the tank. It provides controllable air supply throughout the composting process and is a crucial component for achieving efficient nitrogen retention. By continuously pumping air into the tank, it maintains an aerobic environment at each fermentation stage, effectively increasing the redox potential within the tank, inhibiting the activity of denitrifying bacteria, and reducing nitrogen loss through the conversion of nitrogen gas and nitrous oxide. Simultaneously, it replenishes oxygen to deeper layers of material within the tank, alleviating localized oxygen deficiency caused by material compaction, promoting the growth, reproduction, and metabolism of aerobic microorganisms, and accelerating material maturation.

[0053] Example 1

[0054] A method for composting organic waste to reduce nitrogen loss, such as Figure 2 As shown, the steps are as follows:

[0055] (1) Select organic waste as composting raw material. The organic waste is selected from one or more mixtures of livestock and poultry manure, crop straw and kitchen waste. The selected organic waste is pretreated and fully mixed. The mixing is carried out by a mixer or manual turning to ensure that the materials are mixed evenly.

[0056] If multiple organic wastes are mixed for composting, the carbon-nitrogen ratio needs to be adjusted according to the characteristics of the materials so that the carbon-nitrogen ratio of the mixed materials is controlled at 25~30:1, so as to provide suitable nutritional conditions for the growth and reproduction of microorganisms.

[0057] Carbon-nitrogen ratio adjustment method: First, determine the carbon-nitrogen ratio of each individual organic waste. Based on the target carbon-nitrogen ratio of 25~30:1, calculate and adjust the ratio of each material by adding high-carbon materials (straw, sawdust, etc.) or high-nitrogen materials (livestock and poultry manure, urea, etc.).

[0058] The pretreatment method is as follows: impurities in the material are removed by manual screening or mechanical sorting to avoid impurities affecting the composting process and the quality of the final product; then the material is crushed to a particle size of 2-5cm to ensure good air permeability between materials, while increasing the contact area between microorganisms and materials, which is conducive to subsequent microbial decomposition.

[0059] (2) Place the material obtained after mixing in step (1) into a sealed fermentation tank, filling the volume to 80-90% of the effective volume of the sealed fermentation tank, leaving space for fermentation expansion and gas exchange; add calcium peroxide in sections according to a specific method and pile it evenly. Turn it over every 2-3 days during the fermentation process (the purpose of turning it over every 2-3 days is to: increase the porosity and aeration of the material, maintain an aerobic fermentation environment; make the calcium peroxide evenly distributed, enhance the nitrogen preservation effect; remove CO2, water vapor and odor, optimize the fermentation microenvironment; make the material temperature, moisture content and microbial activity evenly distributed, avoid local anaerobic and nitrogen loss, and accelerate the decomposition process), until the decomposition is completed; the composting fermentation cycle is 28 days, which is 5-10 days shorter than the traditional composting cycle (30-40 days);

[0060] The specific steps for adding calcium peroxide in stages are as follows: calcium peroxide is added during the four stages of heating, high temperature, cooling, and maturation. The amount added in each stage is 1% of the total dry weight of the compost. (A calcium peroxide addition method using the initial total dry weight as a unified measurement benchmark is adopted, that is: the initial total dry weight M obtained by drying and measuring all organic matrix and auxiliary materials at the beginning of composting is used as the sole calculation benchmark for the entire cycle, and the stage addition amount of calcium peroxide is preset to a fixed proportion r (1%) of the initial total dry weight; when each process stage reaches the preset time node, it is not necessary to remeasure the current pile body.) The total dry weight is determined by directly weighing the fixed weight m of calcium peroxide calculated using m=M×r and adding it in stages. By strictly fixing the addition amount to the initial dry matter baseline, the interference of stage dry weight changes caused by real-time fluctuations in total dry weight during the high-temperature degradation stage of composting, due to continuous mineralization and moisture evaporation of the material caused by microbial activity, is effectively avoided. This achieves precise, stable, and traceable control of the calcium peroxide addition amount. The purity of calcium peroxide in each stage is ≥50%, and the particle size is 150~200 mesh. After addition, it is mixed evenly using a mixer or manually.

[0061] The method for achieving uniform material mixing is as follows: During operation, the tank is briefly opened, and manual operation is used to perform layered and zoned, top-to-bottom and radial displacement turning of the material inside the sealed fermentation tank. Long-handled tools are used to loosen the material from top to bottom, breaking up clumps and brittle blocks. Material deposited at the bottom of the tank is moved to the surface, and material on the surface is moved to the middle and lower parts. At the same time, diagonal displacement and internal-external exchange are carried out along the circumference and radial direction of the tank, so that the material can achieve sufficient convection and mixing in both vertical and horizontal directions. The material is kept in a loose state throughout the process, avoiding trampling and compaction, eliminating dead corners and stratification in the tank. This ensures uniform material mixing and consistent aeration in a sealed environment, guaranteeing a stable and uniform fermentation process. After stirring and turning, the tank is quickly closed to avoid disturbance to the fermentation environment inside the tank, gas leakage, and temperature fluctuations.

[0062] (3) The criteria for determining compost maturity include the following three items, which must be met simultaneously:

[0063] Temperature index: If the temperature of the pile drops to ambient temperature and remains stable for 5-7 days without significant temperature rebound, it indicates that the decomposition of organic matter in the pile is basically complete and the activity of microorganisms is significantly reduced. The method for measuring the temperature index is as follows: Open the lid at regular intervals each day and use a thermometer to directly insert into different areas of the pile (upper, middle, and lower layers) to measure the temperature. Each time the temperature is measured, ensure that the temperature sensor probe is fully inserted into the pile and in full contact with the material. Record the temperature data after the reading stabilizes. After the temperature measurement is completed, quickly close the lid to reduce disturbance to the fermentation environment inside the tank and prevent gas leakage and temperature fluctuations. Measure continuously for 5-7 days. If the daily measured temperature of the pile drops to ambient temperature without significant temperature rebound, the temperature index can be judged to have met the standard.

[0064] pH value index: The pH value of the fermentation tank is stable between 6.5 and 8.0; Measurement method: Through the pre-set sealed sampling port of the closed fermentation tank, samples are collected from the upper, middle and lower layers of the tank using a sealed sampler. The sampler is sealed immediately after sampling. The sample is mixed with ultrapure water in a certain proportion, stirred and allowed to stand. The pH value of the supernatant is measured using a pH meter with an accuracy of ≥0.01. The measurement is completed when the pH value is stable between 6.5 and 8.0 for three consecutive sampling measurements.

[0065] C / N ratio index: The C / N ratio of compost drops to 15~20:1, which is close to the C / N ratio of soil, indicating that the organic matter in the compost has been fully decomposed and is unlikely to compete with crops for nitrogen after being applied to the soil; Measurement method: Using the same closed sampling method as above, mixed samples of the compost were collected from different areas of the container; After drying and crushing the samples, the organic carbon content was determined by potassium dichromate oxidation-external heating method, and the total nitrogen content was determined by Kjeldahl method. The ratio of the two was calculated as the C / N ratio; The measurement was completed when the ratio remained stable at 15~20:1 for two consecutive sampling measurements.

[0066] When compost meets all three of the above indicators, it is determined that the compost has completed decomposition and fermentation can be stopped (stop turning, aeration and oxygen supply and the addition of external agents, the compost enters the natural aging stage, and the fermentation process terminates on its own), and the decomposed compost product is obtained.

[0067] This invention innovatively applies calcium peroxide to nitrogen retention in organic waste composting. Its advantage lies in leveraging the synergistic effects of calcium peroxide's multiple properties to achieve comprehensive and efficient nitrogen retention. Adding calcium peroxide in stages during the four stages of composting—heating, high temperature, cooling, and maturation—allows for precise nitrogen retention throughout the entire process: during the heating stage, adding a certain amount of calcium peroxide can slowly release oxygen, improving the initial hypoxic microenvironment; simultaneously, calcium peroxide can stabilize the system's pH value, reducing the large-scale volatilization of ammonia nitrogen (in the composting system, the form of nitrogen depends on the dynamic acid-base balance, the core of which is ammonium ions (NH4+)). + The interconversion equilibrium between NH3 and ammonia (NH4); when the composting environment is maintained in a highly alkaline range (pH > 8.5), according to the principle of chemical equilibrium shift (NH3 + H2O ⇌ NH4), + +OH − ), hydroxide ions (OH-) in the system − A sharp increase in NH4 concentration will force the equilibrium to shift to the left, resulting in a large amount of NH4. +The nitrogen is converted into free NH3; however, NH3 is highly volatile and will rapidly escape from the pores of the pile, causing serious nitrogen loss. This invention utilizes calcium peroxide, whose hydrolysis rate decreases with increasing ambient pH when the pH reaches 7.0 or higher. Constrained by this kinetic characteristic, the system pH is naturally limited and stabilized within a slightly alkaline range (7.0~8.5), avoiding the formation of an extremely alkaline environment. This significantly inhibits the conversion pathway of ammonium ions to molecular ammonia, effectively limiting the volatilization and escape of ammonia nitrogen in the form of molecular ammonia. During the high-temperature stage, the added calcium peroxide can continuously supply oxygen, maintaining the oxygen concentration of the entire system, achieving efficient aerobic fermentation, significantly inhibiting denitrification, reducing gaseous nitrogen loss, and further reducing ammonia escape in conjunction with pH adjustment. During the cooling phase, calcium peroxide continues to optimize oxygen partial pressure and inhibit the activity of denitrifying microorganisms. (During the cooling phase, calcium peroxide releases oxygen through continuous and slow hydrolysis, constructing and maintaining a high oxygen partial pressure environment within the composting system. Based on the principle of "oxygen inhibition," it directly blocks the dependence of denitrifying microorganisms on anaerobic respiration pathways, while simultaneously inhibiting the activity and expression of key denitrifying enzyme systems (such as nitrate reductase and nitrite reductase). The calcium hydroxide produced by hydrolysis stabilizes the pH of the system in a slightly alkaline range (7.0~8.5). This pH environment deviates from the optimal growth and metabolic range of denitrifying microorganisms, selectively suppressing their population activity through protein conformational changes and enzyme activity inhibition. In addition, the calcium ions released by the decomposition of calcium peroxide can regulate the cell membrane permeability and extracellular polymer structure of the compost micro-interface, interfering with the quorum sensing and energy metabolism of denitrifying bacteria, further synergistically inhibiting their proliferation and metabolic activity, thereby effectively curbing the irreversible loss of nitrogen through denitrification in gaseous forms such as N2 and N2O.) It continuously regulates the pH to prevent secondary volatilization of ammonia nitrogen. During the composting stage, calcium peroxide promotes the conversion of nitrogen to a stable form by maintaining the dual stability of the oxygen environment and pH. (During the composting stage, on the one hand, calcium peroxide continuously releases oxygen upon contact with water, maintaining the compost in an aerobic microenvironment, effectively inhibiting secondary denitrification mediated by denitrifying bacteria under anaerobic conditions, blocking the reverse conversion of nitrate nitrogen to gaseous nitrogen such as nitrogen gas or nitrous oxide, thereby reducing the gaseous loss of nitrogen; on the other hand, calcium peroxide hydrolyzes to release calcium hydroxide, stabilizing the pH of the system in the slightly alkaline range of 7.0~8.5. This pH environment promotes the conversion of free ammonium ions into solid-phase adsorbed ammonium salts or combines with organic matter to form ammonium-organic complexes, achieving chemical fixation of nitrogen. On the other hand, it activates the metabolic activity of the humifying microbial community, promoting the conversion of nitrogen from an unstable free small molecule form to a structurally stable, leaching-resistant humic acid-bound macromolecule, ultimately achieving efficient locking and long-term stability of nitrogen in the solid-phase system), thereby improving the composting maturity and product fertilizer efficiency.

[0068] This invention adds calcium peroxide at different stages of organic waste fermentation. On the one hand, it maintains the oxygen environment of the compost system and inhibits denitrification; on the other hand, it reduces ammonia volatilization by regulating the pH environment of the system. This dual synergistic effect continuously enhances the entire composting fermentation process. Oxygen supply regulation fundamentally blocks the loss of gaseous nitrogen caused by denitrification, while pH regulation effectively inhibits the volatilization of free ammonia. These two effects work together throughout the entire process, achieving highly efficient nitrogen retention of organic waste raw materials from fermentation initiation to stable composting maturity. This effectively solves the problems of poor performance, high cost, and secondary pollution caused by existing nitrogen retention technologies, as well as their impact on composting maturity.

[0069] Compared to traditional processes, which involve adding calcium peroxide all at once during the initial fermentation stage of composting, the segmented addition process employed in this invention significantly improves nitrogen utilization efficiency and product stability during composting, resulting in substantial environmental and economic benefits. Traditional one-time addition methods often lead to drastic pH fluctuations in the compost pile during the initial fermentation stage. Excessive alkalinity not only inhibits the activity and metabolism of thermophilic microorganisms, delaying composting initiation and heating, but also causes rapid consumption of calcium peroxide and subsequent oxygen supply disruptions. Furthermore, during the cooling and maturation stages, the resurgence of the anaerobic environment easily induces a surge in denitrifying bacteria, leading to a large-scale irreversible loss of nitrogen through denitrification in gaseous forms such as N2 and N2O. In contrast, this invention achieves dynamic regulation of the compost microenvironment throughout its entire lifecycle by adding calcium peroxide in stages during the heating, cooling, and maturation phases. First, this strategy avoids the risk of localized excessive alkalinity, maintaining the system's pH value stable within the optimal activity range of 7.0–8.5, ensuring the continuous and efficient metabolism of the microbial community. Second, calcium peroxide slowly releases oxygen throughout the fermentation cycle, constructing and maintaining a high oxygen partial pressure environment, fundamentally inhibiting the expression and activity of key denitrification enzymes, and effectively blocking nitrogen denitrification loss. Finally, the continuous slightly alkaline environment and the effect of calcium ions promote the condensation polymerization of humic acid and the solid-phase stabilization of nitrogen, significantly improving the total nitrogen retention rate and humification degree of the compost product.

[0070] Example 2

[0071] Unlike Example 1, calcium peroxide was added in all four stages of composting. The amount added during the heating, cooling and maturation stages remained 1% of the total dry weight of the compost (consistent with Example 1). Only the amount of calcium peroxide added during the high-temperature stage was adjusted to 0.1% of the total dry weight of the compost. The other steps were consistent with Example 1.

[0072] Nitrogen retention effect test: The Kjeldahl method described in Example 1 was used to determine the total nitrogen content of the compost at the beginning and after composting, and the nitrogen loss rate was calculated. The test results showed that after composting in this example, the total nitrogen loss rate was 23.1%, which is lower than that of conventional compost without added calcium peroxide (nitrogen loss rate of 32%), achieving a basic nitrogen retention effect. Furthermore, all indicators of the compost product met the composting standards and were consistent with the quality of the composted product in Example 1. Simultaneously, it was verified that this minimum addition amount does not inhibit the activity of composting microorganisms, ensuring the normal progress of the composting process.

[0073] Example 3

[0074] Unlike Example 1, calcium peroxide was added in all four stages of composting. The amount added during the heating, cooling and maturation stages was still 1% of the total dry weight of the compost (consistent with Example 1). The only difference was that the amount of calcium peroxide added during the high-temperature stage was set to five gradients: 1%, 2%, 3%, 4% and 5% of the total dry weight of the compost. All other processes and steps were consistent with Example 1.

[0075] By comparing the nitrogen retention effects and compost product quality at different gradients, the optimal addition ratio of calcium peroxide during high-temperature periods was determined as follows:

[0076] (1) Organic waste pretreatment: Same as in Example 1, select organic waste and pretreatment, adjust the carbon-nitrogen ratio of the mixture to 25~30:1, crush to a particle size of 2~5cm, remove impurities and mix evenly; divide into 5 groups, each group with consistent material quality, numbered as group 1 to group 5.

[0077] (2) Closed fermentation and calcium peroxide addition: The five groups of materials were placed in closed fermentation tanks of the same specifications. The filling volume was 80-90% of the effective volume of the corresponding closed fermentation tank. During the fermentation process, the materials were piled up and turned evenly every 2-3 days according to the method described in Example 1. The composting fermentation cycle was 28 days.

[0078] Calcium peroxide addition method: Calcium peroxide was added to all 5 groups in the four stages of composting. The amount added during the heating, cooling and maturation stages was 1% of the total dry weight of the compost. The purity of the calcium peroxide was ≥50% and the particle size was 150~200 mesh. After addition, it was stirred and mixed evenly according to the method described in Example 1. Only the addition amount during the high temperature stage (the temperature of the pile body is stable at 55℃ or above and lasts for 3 days) was set with different gradients. The addition amounts of each group during the high temperature stage were: Group 1 (1%), Group 2 (2%), Group 3 (3%), Group 4 (4%), and Group 5 (5%). The purity, particle size and mixing method of calcium peroxide during the high temperature stage were the same as those in other stages.

[0079] (3) Determination of compost maturity: Same as in Example 1, the maturity of each group of compost is determined by three indicators: temperature, pH value and C / N ratio. Fermentation is stopped when all three indicators are met.

[0080] (4) Index detection and optimal ratio screening: Using the method described in Example 1, the total nitrogen content, pH value, C / N ratio and germination index of each group of compost were measured at the beginning and after decomposition. The nitrogen loss rate was calculated, the nitrogen retention effect of each group was compared, and the optimal addition ratio was screened.

[0081] The specific test results are as follows:

[0082] Group 1 (1% addition) had a nitrogen loss rate of 18.7% and a pH value of 7.4 after composting, with no abnormalities in the composting process;

[0083] Group 2 (2% addition) had a nitrogen loss rate of 16.2% and a pH value of 7.5 after composting, with no abnormalities in the composting process;

[0084] Group 3 (3% addition) had a nitrogen loss rate of 15.1% and a pH value of 7.6 after composting, with no abnormalities in the composting process;

[0085] Group 4 (4% addition) had a nitrogen loss rate of 15.3% and a pH value of 7.9 after composting, with no abnormalities in the composting process;

[0086] Group 5 (5% addition) had a nitrogen loss rate of 15.5% and a pH value of 8.2 after composting. The composting process showed no obvious abnormalities, but the pH value slightly exceeded the optimal range of 6.5 to 8.0.

[0087] Screening Conclusion: The test results show that within the range of 1-5% calcium peroxide added during the high-temperature composting period, nitrogen loss initially decreases with increasing dosage. When the dosage reaches 3%, the nitrogen loss rate reaches its lowest point (15.1%), a reduction of 16.9% compared to conventional compost without added calcium peroxide. Further increasing the dosage to 4% and 5% does not significantly decrease the nitrogen loss rate; instead, it slightly increases. Furthermore, the pH value of group 5 (5% dosage) compost after maturation slightly exceeds the optimal range of 6.5-8.0. Although there is no obvious abnormality in the composting process, it will affect the subsequent application effect of the compost product. Meanwhile, the pH value and other parameters of group 3 (3% dosage) compost after maturation are within the optimal range, indicating the best compost product quality. Therefore, the optimal addition ratio of calcium peroxide during the high-temperature composting period is 3% of the total dry weight of the compost.

[0088] Example 4

[0089] Unlike Example 1, the calcium peroxide powder (purity ≥50%, particle size 150 mesh) is replaced with calcium peroxide granules or slow-release calcium peroxide granules (i.e., membrane-coated calcium peroxide). The particle size of the calcium peroxide granules is rationally selected based on the composting process adaptability and oxygen release rate requirements.

[0090] The specific implementation method is as follows: In each cycle, according to the original dosage range, calcium peroxide particles or slow-release calcium peroxide particles are buried in layers at different depths in the pile body (in order to ensure the uniformity and stability of the internal environment of the pile body, it is recommended that the depth range of the layer burial be set as follows: the first layer is buried 5~10cm below the surface of the pile body; the second layer is buried 20~30cm in the middle layer of the pile body; and the third layer is buried 40~50cm at the bottom layer of the pile body). After burying, the turning and throwing process is started to ensure that the particles are in full and uniform contact with the pile body.

[0091] The hydrolysis rate of calcium peroxide granules or slow-release calcium peroxide granules is slightly slower than that of powder, which can achieve a more sustained oxygen release effect and adapt to the aerobic requirements of each cycle. Layered burial can avoid the concentrated distribution of calcium peroxide, further reducing the problem of sudden local pH rise or excessive oxygen content. At the same time, turning and mixing can ensure that it is in full contact with the pile body, and can still achieve the purpose of nitrogen preservation in each cycle. It is consistent with the core mechanism of action of the original technical solution in Example 1, only changing the form of calcium peroxide and the distribution method when adding it, without affecting the achievement of the invention purpose.

[0092] Preferably, the particle size of calcium peroxide particles is controlled at 1~3mm. This particle size range can effectively avoid the problem of excessively rapid hydrolysis reaction and unsustainable oxygen release of powdered calcium peroxide. At the same time, it is conducive to full contact and mixing between the particles and the compost material, and to a certain extent, it takes into account both the continuity of oxygen release and the uniformity of material mixing, which can better meet the oxygen supply needs of different stages of composting.

[0093] The slow-release calcium peroxide (membrane-coated calcium peroxide) particles used in this embodiment are made with calcium peroxide particles as the core material and cellulose as the coating material. The specific preparation process is as follows:

[0094] First, cellulose is coated onto the surface of calcium peroxide particles to form a core-shell structure. The mass ratio of calcium peroxide particles in the sustained-release particles is strictly controlled to be 60%~65%. Then, the particles are granulated using a granulator to finally produce calcium peroxide sustained-release particles with a particle size of 2.5mm~3mm.

[0095] This granulation process ensures good granule formation and high density, and the cellulose coating and particle size control after granulation together achieve the slow-release effect of calcium peroxide.

[0096] The difference between the final nitrogen content effect of the compost and that of Example 1 using powdered calcium peroxide: There was no significant difference in the final nitrogen content of the compost from both methods, and both were able to achieve the goal of efficient nitrogen retention. Compared with powdered calcium peroxide, the nitrogen retention rate of compost was improved when using granular or slow-release calcium peroxide granules. This was mainly because the hydrolysis rate of granular particles was slower, and the oxygen release and pH regulation were more persistent and stable, which could effectively reduce local nitrogen loss. At the same time, slow-release calcium peroxide granules, due to their longer oxygen release cycle, could better maintain nitrogen stability during the composting maturation stage, further improving the stability of the nitrogen content of the compost product, ensuring that the final fertilizer effect was consistent with the original technical solution, and without additional cost increase or secondary pollution risk.

[0097] Example 5

[0098] Unlike Example 1, in addition to adding calcium peroxide in each cycle, a small amount of auxiliary nitrogen-retaining agent (bentonite, the amount added is 1~2% of the dry weight of the pile) is added. The auxiliary nitrogen-retaining agent is added and mixed with calcium peroxide at the same time. Other steps and processes (addition dosage, cycle determination, device control, etc.) remain unchanged.

[0099] Bentonite has excellent adsorption properties and can adsorb ammonium nitrogen in the pile, further reducing ammonia volatilization. It works synergistically with the nitrogen retention mechanism of calcium peroxide to achieve the same nitrogen retention purpose and further enhance the nitrogen retention effect.

[0100] Combining the nitrogen-retention adsorption properties of bentonite with the composting environment-regulating properties of calcium peroxide, a synergistic nitrogen-retention mechanism is formed in the composting system, complementing environmental regulation and solid-phase adsorption. Calcium peroxide regulates the oxygen partial pressure in the compost pile through slow oxygen release, inhibiting denitrification to reduce gaseous nitrogen loss. Simultaneously, its hydrolysis products buffer the pH value of the compost pile, preventing excessive pH increases that could lead to the conversion of ammonium nitrogen into free ammonia. This directly reduces ammonia volatilization loss and creates a stable composting microenvironment for bentonite, ensuring the integrity of its layered structure and ion exchange sites. It also reduces competition from organic matter degradation products for these adsorption sites, improving the adsorption efficiency and stability of bentonite for ammonium nitrogen. Bentonite, relying on its high specific surface area and ion exchange performance due to its layered silicate structure, directly adsorbs and fixes ammonium nitrogen in the compost, addressing nitrogen loss at its source. Bentonite reduces the concentration of free ammonia in the compost pile, forming a dual ammonia volatilization inhibition effect with calcium peroxide. At the same time, bentonite can increase the activity of nitrifying bacteria in the composting system, promote the later-stage nitrification of compost, and promote the conversion and retention of ammonium nitrogen to nitrate nitrogen. This works in conjunction with the denitrification inhibition effect of calcium peroxide to achieve control over the entire nitrogen conversion process. Moreover, bentonite has no significant negative impact on the pH and EC values ​​of the compost pile, and will not interfere with the regulation of compost microbial activity by calcium peroxide or the normal high-temperature composting process. The calcium-based properties and corrosion-inhibiting oxygen-releasing characteristics of calcium peroxide will not damage the crystal structure and adsorption performance of bentonite. The two do not have antagonistic physical and chemical effects in the composting system. While each plays its own role in nitrogen retention, they promote each other, synergistically reducing nitrogen loss caused by ammonia volatilization and denitrification, and significantly improving the overall nitrogen retention effect of compost.

Claims

1. A method for composting organic waste to reduce nitrogen loss, characterized in that, In the four stages of organic waste composting—heating, high temperature, cooling, and maturation—calcium peroxide is added to maintain the aerobic environment of the composting system, inhibit denitrification, and reduce the volatilization of free ammonia by regulating the pH of the composting system.

2. The method for composting organic waste to reduce nitrogen loss according to claim 1, characterized in that, During the heating period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; during the high-temperature period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; during the cooling period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost; during the maturation period, the amount of calcium peroxide added is 0.1-5% of the total dry weight of the compost.

3. The method for composting organic waste to reduce nitrogen loss according to claim 1, characterized in that, The calcium peroxide has a purity of ≥50% and a particle size of 150~200 mesh.

4. The method for composting organic waste to reduce nitrogen loss according to claim 1, characterized in that, The organic waste is selected from one or more mixtures of livestock and poultry manure, crop straw, and kitchen waste; the carbon-to-nitrogen ratio of the organic waste is 25-30:

1.

5. The method for composting organic waste to reduce nitrogen loss according to any one of claims 1 to 4, characterized in that, The steps are as follows: S1: Select organic waste as composting raw material, then pre-treat it, mix it thoroughly, and use a mixer or manual turning to ensure that the material is mixed evenly; S2: Fill the material obtained in S1 into a sealed fermentation tank, add calcium peroxide during the heating period, high temperature period, cooling period and decomposition period and pile it up evenly. Turn it over every 2 to 3 days during the fermentation process until decomposition is complete. During the heating period, the amount of calcium peroxide added is 1% of the total dry weight of the compost; During the high-temperature period, the amount of calcium peroxide added is 0.1% to 5% of the total dry weight of the compost. During the cooling period, the amount of calcium peroxide added is 1% of the total dry weight of the compost; During the composting period, the amount of calcium peroxide added is 1% of the total dry weight of the compost. S3: The compost that has been fully decomposed in S2 is judged by indicators. When the compost meets the standards, it is judged that the compost is fully decomposed, fermentation is stopped, the pile enters the natural aging stage, the fermentation process terminates on its own, and the decomposed compost product is obtained. When the compost does not meet the standards, it is returned to S2 to continue fermentation, and the indicators are tested again.

6. The method for composting organic waste to reduce nitrogen loss according to claim 5, characterized in that, In S1, the pretreatment method is to remove impurities from the material by manual screening or mechanical sorting, and then crush the material to a particle size of 2-5 cm.

7. The method for composting organic waste to reduce nitrogen loss according to claim 5, characterized in that, In S2, the method for uniformly turning over the material is as follows: During operation, the tank is briefly opened, and manual operation is used to perform layered and zoned, top-to-bottom replacement and radial displacement turning operations on the material in the sealed fermentation tank. Long-handled tools are used to loosen the material from top to bottom and break up clumps. The material deposited at the bottom of the tank is turned over to the surface, and the surface material is replaced to the middle and lower parts. At the same time, diagonal displacement and internal and external exchange are carried out along the circumference and radial direction of the tank, so that the material can achieve full convection and mixing in both the vertical and horizontal directions. The material is kept in a loose state throughout the process to avoid trampling and compaction, eliminate dead corners and stratification in the tank, and achieve uniform material turning and consistent aeration in a sealed environment to ensure a stable and uniform fermentation process. After the stirring and turning are completed, the tank is quickly closed to avoid disturbance of the fermentation environment inside the tank, gas leakage, and temperature fluctuations.

8. The method for composting organic waste to reduce nitrogen loss according to claim 5, characterized in that, In S3, the indicators for determining compost maturity include temperature, pH and C / N ratio. The temperature index is determined as follows: the lid is opened at a set time each day, and a temperature measuring device is directly inserted into the upper, middle, and lower layers of the pile to measure the temperature. Each time the temperature is measured, ensure that the probe of the temperature measuring device is fully inserted into the pile and in full contact with the material. Record the temperature data after the reading stabilizes. After the temperature measurement is completed, the lid is closed quickly to reduce disturbance to the fermentation environment inside the tank and prevent gas leakage and temperature fluctuations. Measure continuously for 5 to 7 days. If the temperature of the pile measured each day drops to the ambient temperature and there is no obvious temperature rebound, the temperature index can be determined to meet the standard. The pH index was determined as follows: samples were collected from the upper, middle and lower layers of the fermenter using a sealed sampler through the pre-set sealed sampling port. The sampler was then sealed immediately after sampling. The sample was mixed with ultrapure water in a certain proportion, stirred and allowed to stand. The pH value of the supernatant was measured using a pH meter with an accuracy of ≥0.

01. The pH value was considered complete if it remained stable between 6.5 and 8.0 after three consecutive sampling measurements. The determination of the C / N ratio index is as follows: a mixed sample of the stockpile is collected in different areas of the tank through a closed sampling method; after the sample is dried and crushed, the organic carbon content is determined by potassium dichromate oxidation-external heating method, and the total nitrogen content is determined by Kjeldahl method. The ratio of the two is the C / N ratio; if the ratio is stable at 15~20:1 for two consecutive sampling measurements, the determination is completed.

9. The method for composting organic waste to reduce nitrogen loss according to claim 5, characterized in that, In S2, after the material is filled into the sealed fermentation tank, calcium peroxide particles or slow-release calcium peroxide particles can be added in stages. The particle size of the calcium peroxide particles is controlled at 1~3mm; the slow-release calcium peroxide particles are prepared by using calcium peroxide particles as the core material and cellulose as the coating material: first, cellulose is coated on the surface of the calcium peroxide particles to form a core-shell structure, wherein the mass ratio of calcium peroxide particles in the slow-release particles is strictly controlled at 60%~65%, and then granulated by a granulator to finally produce calcium peroxide slow-release particles with a particle size of 2.5mm~3mm.

10. The method for composting organic waste to reduce nitrogen loss according to claim 5, characterized in that, In step S2, calcium peroxide and a small amount of auxiliary nitrogen-retaining agent are added simultaneously at each stage when the material is loaded into the sealed fermentation tank; the auxiliary nitrogen-retaining agent is bentonite, and the amount added is 1 to 2% of the dry weight of the pile.

Images