Method for rapidly raising temperature of kitchen garbage aerobic compost by using dry anaerobic biogas residue initiation
By mixing dry anaerobic digestate with kitchen waste and adding rice husks, and using methods such as turning, aeration, and water replenishment, the problem of slow temperature rise in kitchen waste composting was solved, achieving rapid temperature rise and efficient maturation, thus improving composting efficiency and product quality.
Patent Information
- Application Number
- CN202511610117.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-01-09
AI Technical Summary
Existing technologies lack a systematic approach to applying dry anaerobic digester residue to kitchen waste composting, resulting in slow composting temperature rise. Furthermore, existing initiators are costly and have limited effectiveness, making it difficult to achieve rapid temperature rise and efficient decomposition.
Dry anaerobic digester residue is mixed with kitchen waste in a 1:1 ratio, and rice husks are added to adjust the moisture content to 50%-60%. Composting is started at 25-37℃, and the moisture content of the material is controlled by turning the pile for aeration and adding water to achieve rapid heating and sustained high temperature period.
It enables compost to reach high temperatures (>55℃) within 3 days, maintain the high temperature period for more than 10 days, achieve a high degree of maturity, reduce ammonia volatilization and greenhouse gas emissions, and improve composting efficiency and product quality.
Smart Images
Figure CN121293024A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of kitchen waste treatment technology, and in particular to a method for rapidly heating up aerobic composting of kitchen waste using dry anaerobic digester residue. Background Technology
[0002] With the implementation of waste sorting policies, the amount of kitchen waste separated has increased dramatically, but its treatment faces challenges. Kitchen waste is characterized by high moisture content (70%-90%), low porosity, rich in recalcitrant substances such as protein, oil, and cellulose, and low pH (4-5), resulting in slow heating during aerobic composting and the need for initiators for efficient startup. Existing initiators include microbial agents and readily biodegradable organic matter, but they are costly and have limited effectiveness. Meanwhile, the annual output of biogas residue generated during dry anaerobic digestion is enormous (estimated at 4.5 million tons by 2025), and its treatment methods, such as pyrolysis and landfill, pose environmental risks. Land application and aerobic co-composting are more sustainable approaches. Research shows that dry anaerobic biogas residue has characteristics such as low moisture content (55%-70%), low organic matter content, abundant biomass, loose and porous structure, and weak alkalinity (pH 8-9). It is rich in volatile organic acids (VFAs) and thermophilic bacteria, which can effectively initiate the composting of kitchen waste. However, existing technologies lack a systematic approach to using biogas residue as an initiator in the composting of kitchen waste to achieve rapid heating and efficient decomposition.
[0003] Therefore, it is necessary to provide a method for rapidly heating up the aerobic composting of kitchen waste using dry anaerobic biogas residue to solve the above-mentioned technical problems. Summary of the Invention
[0004] The technical problem solved by this invention is to provide a method for rapidly heating up aerobic composting of kitchen waste using dry anaerobic digester residue, which can achieve rapid heating, sustained high temperature period, reduced nitrogen loss, reduced greenhouse gas emissions, and enhanced humification, thereby improving composting efficiency and product quality.
[0005] To solve the above-mentioned technical problems, the present invention provides a method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue, comprising the following steps:
[0006] S1: Collect kitchen waste materials, filter out oil and water, so that the moisture content of the filtered kitchen waste materials is 70%-90% of the total material;
[0007] S2: Sorting the kitchen waste material in S1, removing non-degradable materials, and crushing it until the material is similar to a paste;
[0008] S3: Collect dry anaerobic digester residue material and control the moisture content of the dry anaerobic digester residue material to 55%-70%;
[0009] S4: The dry anaerobic digestate in S3 is sorted to remove non-degradable materials and crushed until the material is similar to soil and the pH is 8-9.
[0010] S5: Mix the pulverized kitchen waste material obtained in S2 and the pulverized dry anaerobic digester residue material obtained in S4 at a wet weight ratio of 1:1 to obtain a mixture.
[0011] S6: Add rice husks, accounting for 30%-40% of the mixture in S5, to make the final mixture have a moisture content of 50%-60% and mix evenly;
[0012] S7: Place the material with added rice husks obtained in S6 into the compost bin, and start composting by controlling the ambient temperature of the compost bin at 25-37℃;
[0013] S8: After the material in S7 is cooled to below 55°C, continue to turn the pile to ventilate the material and stop adding water. Continue for 1-2 weeks to complete the maturation and volume reduction of the material.
[0014] Preferably, the non-degradable materials include plastics, metals, and bones.
[0015] Preferably, in step S2, the pH of the sorted and crushed kitchen waste material is 4-5.
[0016] Preferably, in step S4, the pH of the sorted and crushed dry anaerobic digestate is 8-9.
[0017] Preferably, in step S5, the pH of the mixture is 7-8.
[0018] Preferably, in step S7, after the composting is started, the material temperature rises to above 55°C and then drops. During this period, the compost is turned and aerated at fixed times every day, and the moisture content of the compost material is controlled at 50%-60% by adding water.
[0019] Compared with related technologies, the method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue provided by this invention has the following beneficial effects:
[0020] This invention provides a method for rapidly raising the temperature of aerobic composting of kitchen waste using dry anaerobic digester residue. The digester residue provides abundant microorganisms and easily degradable organic matter, enabling the compost to reach a high temperature (>55℃) within 3 days, significantly shorter than that of pure kitchen waste compost (7 days). The high-temperature period is maintained for more than 10 days, meeting the standard requirements (>5 days), and the degree of decomposition is high. The alkalinity of the digester residue neutralizes the acidity of the kitchen waste, reducing ammonia volatilization and total nitrogen loss. The addition of digester residue can delay the peak of N2O emissions and reduce cumulative emissions. The addition of kitchen waste can reduce CH4 emissions from digester residue composting alone. Three-dimensional fluorescence spectroscopy shows that the humification index (HIX) of the mixed group increased by 31.81%, indicating enhanced humic synthesis. Attached Figure Description
[0021] Figure 1 This is a graph showing the change in pile temperature with composting time in the embodiment.
[0022] Figure 2 This is a graph showing the variation of the physicochemical characteristics of the compost pile over composting time in the embodiment.
[0023] Figure 3 This is a diagram showing the variation of the three-dimensional fluorescence spectral characteristics of the compost pile over time in the embodiment.
[0024] Figure 4 The BOD5 / COD and VFAs characteristics of different initial samples of the heap in the examples are shown.
[0025] Figure 5 This is a graph showing the variation of cumulative N2O and CH4 emissions from the compost pile over time in the embodiment.
[0026] Figure 6 This is a table showing the changes in the phylum-level microbial community structure of the compost pile over time, as illustrated in the examples. Detailed Implementation
[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0028] Please refer to the following: Figures 1-6 ,in, Figure 1 This is a graph showing the change in pile temperature with composting time in the embodiment. Figure 2 This is a graph showing the variation of the physicochemical characteristics of the compost pile over composting time in the embodiment. Figure 3 This is a diagram showing the variation of the three-dimensional fluorescence spectral characteristics of the compost pile over time in the embodiment. Figure 4 The BOD5 / COD and VFAs characteristics of different initial samples of the heap in the examples are shown. Figure 5 This is a graph showing the variation of cumulative N2O and CH4 emissions from the compost pile over time in the embodiment. Figure 6This table shows the changes in the phylum-level microbial community structure of the compost pile over time, as illustrated in the examples. The method for rapidly heating aerobic composting of kitchen waste using dry anaerobic digester residue includes the following steps:
[0029] S1: Collect kitchen waste materials and use a strainer to filter out the oil and water, wherein the moisture content of the filtered kitchen waste materials is 70%-90% of the total materials;
[0030] S2: Sorting the kitchen waste material in S1, removing non-degradable materials such as plastics, metals, and bones, and crushing it until the material is similar to a paste with a pH of 4-5;
[0031] S3: Collect dry anaerobic digester residue material, wherein the moisture content of the dry anaerobic digester residue material is 55%-70%;
[0032] S4: The dry anaerobic digestate from S3 is sorted to remove non-degradable materials such as plastics, metals, and bones, and then crushed until the material is similar to soil and has a pH of 8-9.
[0033] S5: Mix the crushed kitchen waste material obtained in S2 and the crushed dry anaerobic digester residue material obtained in S4 at a ratio of 1:1 by wet weight to obtain a mixture with a pH of 7-8.
[0034] S6: Add rice husks, accounting for 30%-40% of the mixture in S5, to make the final mixture have a moisture content of 50%-60% and mix evenly.
[0035] S7: Place the material with added rice husks obtained in S6 into the compost bin and start composting by controlling the ambient temperature of the compost bin at 25-37℃. After composting starts, the temperature of the material will rise to above 55℃ and eventually fall back below 55℃. During this process, turn the pile and aerate it at fixed times every day, and control the moisture content of the pile material at 50%-60% by adding water.
[0036] S8: After the material in S7 is cooled to below 55℃, continue to turn the pile to ventilate the material and stop adding water. Continue for 1-2 weeks to complete the maturation and volume reduction of the material.
[0037] Example:
[0038] Composting experiment setup:
[0039] Material sources: Kitchen waste was taken from the student canteen of Jimei University; dry anaerobic digestate was taken from the Xiamen Houkeng Waste Sorting and Treatment Plant (using the German STRABAG horizontal plug flow process, with a daily processing capacity of 72 tons and a fermentation cycle of 30 days).
[0040] Pretreatment: Kitchen waste is drained and crushed, with a moisture content of 70%-90% and a pH of 4-5; biogas residue is sorted and crushed, with a moisture content of 55%-70% and a pH of 8-9.
[0041] Experimental groups: Kitchen waste group (C1), biogas residue group (C2), and mixed group (C3). In group C3, the wet weight ratio of kitchen waste to biogas residue was 1:1, and rice husks were added to make the initial moisture content 50%.
[0042] Composting conditions: Each compost pile weighs 8 kg and is placed in a 20L compost bin at an ambient temperature of 37℃. Temperature should be measured daily, the pile turned, and water added to maintain a moisture content of 50%-60%.
[0043] Composting process monitoring:
[0044] Temperature monitoring: such as Figure 1 As shown, group C3 (mixed) reached high temperature (>55℃) on day 5, and the high temperature period lasted for 10 days; group C1 (kitchen waste) reached high temperature on day 7 and lasted for 11 days; group C2 (biogas residue) reached high temperature on day 3 and lasted for 7 days. This indicates that biogas residue explosion accelerates the temperature rise.
[0045] Physicochemical properties: such as Figure 2 As shown, the moisture content was maintained at 45%-60%; the electrical conductivity was <3 mS / cm; the organic matter reduction rate of group C3 was 28.27%, which was higher than that of group C1 (26.10%); the total nitrogen (TN) reduction rate of group C3 was lower than that of group C1.
[0046] Humic analysis: such as Figure 3 As shown, the three-dimensional fluorescence spectrum shows that the fluorescence region V (humic acid-like) of group C3 increased by 31.81%, the humification index (HIX) increased, and the biogenic index (BIX) was relatively high in the early stage, indicating that the biogas residue provides microorganisms and substrates, driving humification.
[0047] Mechanism analysis:
[0048] Organic matter degradation: such as Figure 4 As shown, the biogas residue group had a higher BOD5 / COD ratio and more readily degradable organic matter (VFAs content 2127.54 mg / L) than the kitchen waste group (1779.69 mg / L), indicating that the organic matter was more readily degradable.
[0049] Greenhouse gases: such as Figure 5 As shown, the cumulative N2O emissions from group C3 were 93.72 mg / L. This is lower than group C1 (106.15). CH4 emissions mainly occur in the initial stage, and the addition of kitchen waste reduces the accumulation of CH4.
[0050] Microbial communities: such as Figure 6As shown, 16S rRNA high-throughput sequencing analysis revealed that the mixed group promoted microbial diversity, with phylum-level thermostable Bacillota and Bacteroidota undergoing successive degradation, thus improving composting efficiency.
[0051] Compared with related technologies, the method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue provided by this invention has the following beneficial effects:
[0052] This invention provides a method for rapidly raising the temperature of aerobic composting of kitchen waste using dry anaerobic digester residue. The digester residue provides abundant microorganisms and easily degradable organic matter, enabling the compost to reach a high temperature (>55℃) within 3 days, significantly shorter than that of pure kitchen waste compost (7 days). The high-temperature period is maintained for more than 10 days, meeting the standard requirements (>5 days), and the degree of decomposition is high. The alkalinity of the digester residue neutralizes the acidity of the kitchen waste, reducing ammonia volatilization and total nitrogen loss. The addition of digester residue can delay the peak of N2O emissions and reduce cumulative emissions. The addition of kitchen waste can reduce CH4 emissions from digester residue composting alone. Three-dimensional fluorescence spectroscopy shows that the humification index (HIX) of the mixed group increased by 31.81%, indicating enhanced humic synthesis.
[0053] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for rapidly heating aerobic composting of kitchen waste using dry anaerobic biogas residue ignition, characterized in that, Includes the following steps: S1: Collect kitchen waste materials, filter out oil and water, so that the moisture content of the filtered kitchen waste materials is 70%-90% of the total material; S2: Sorting the kitchen waste material in S1, removing non-degradable materials, and crushing it until the material is similar to a paste; S3: Collect dry anaerobic digester residue material and control the moisture content of the dry anaerobic digester residue material to 55%-70%; S4: The dry anaerobic digestate in S3 is sorted to remove non-degradable materials and crushed until the material is similar to soil and the pH is 8-9. S5: Mix the pulverized kitchen waste material obtained in S2 and the pulverized dry anaerobic digester residue material obtained in S4 at a wet weight ratio of 1:1 to obtain a mixture. S6: Add rice husks, accounting for 30%-40% of the mixture in S5, to make the final mixture have a moisture content of 50%-60% and mix evenly; S7: Place the material with added rice husks obtained in S6 into the compost bin, and start composting by controlling the ambient temperature of the compost bin at 25-37℃; S8: After the material in S7 is cooled to below 55°C, continue to turn the pile to ventilate the material and stop adding water. Continue for 1-2 weeks to complete the maturation and volume reduction of the material.
2. The method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue as described in claim 1, characterized in that, The non-degradable materials include plastics, metals, and bones.
3. The method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue as described in claim 1, characterized in that... In step S2, the pH of the sorted and crushed kitchen waste material is 4-5.
4. The method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue as described in claim 1, characterized in that... In S4, the pH of the sorted and crushed dry anaerobic digestate is 8-9.
5. The method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue as described in claim 1, characterized in that, In step S5, the pH of the mixture is 7-8.
6. The method for rapid heating of aerobic composting of kitchen waste using dry anaerobic biogas residue as described in claim 1, characterized in that, In S7, after the composting is started, the material temperature rises to above 55°C and then drops. During this period, the compost is turned and aerated at fixed times every day, and the moisture content of the compost material is controlled at 50%-60% by adding water.