Method for reducing nitrogen loss by covering aerobic composting system with functional film

Abstract

The invention belongs to the field of resources and environment, and discloses a method for reducing nitrogen loss by covering an aerobic composting system with a functional film. The method comprises the following steps: accurately dividing the space gradient of a pile body, regulating and controlling the temperature and oxygen content of pile layers with different heights, dividing the pile body into five layers according to the highest temperature gradient, and setting the proper oxygen concentration of each layer (the oxygen supply rate is 0.2-0.3 L.kgTS-1. Min <-1 >, and the oxygen concentration of each layer is different); meanwhile, the composition and diversity of bacterial and fungal communities are analyzed by adopting a high-throughput sequencing technology, and the abundance of key functional microorganisms is regulated and controlled. The method effectively solves the problems of resource utilization of livestock and poultry manure and nitrogen loss, can improve the composting quality, shorten the composting period, reduce environmental pollution and promote resource recycling, and has remarkable economic benefits, social benefits and environmental protection benefits.

Description

Technical Field

[0001] The invention belongs to the field of resources and environment, and relates to a method for reducing nitrogen loss in a functional film-covered aerobic composting system. Background Art

[0002] With the vigorous development of animal husbandry in my country, the amount of breeding waste has increased dramatically, and its effective treatment has become a severe challenge facing rural environmental governance. Functional membrane covered aerobic composting (FMCAC), as a common technology for treating rural solid waste, can withstand adverse weather conditions and reduce nitrogen loss during composting to a certain extent. However, the dynamic changes and internal mechanisms of nitrogen loss in the FMCAC process are not yet fully understood, especially in the study of nitrogen transformation on spatial gradients, and there is a lack of detailed and in-depth analysis of the entire system. In summary, it is particularly important and urgent to develop a method to effectively reduce nitrogen loss in the FMCAC system. This will not only help improve the quality and agricultural utilization value of compost products and realize the resource utilization of waste, but also have far-reaching significance for improving the ecological environment quality in rural areas, promoting sustainable agricultural development, and promoting the harmonious coexistence of man and nature. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, a method for reducing nitrogen loss in a functional membrane covered aerobic composting system is disclosed. The method precisely divides the spatial gradient of the pile body, regulates the temperature and oxygen content of the pile layers at different heights, divides the pile body into 5 layers according to the highest temperature gradient, and sets the appropriate oxygen concentration for each layer (oxygen supply rate 0.2-0.3L·kgTS-1·min-1, different oxygen concentrations for each layer). At the same time, high-throughput sequencing technology is used to analyze the composition and diversity of bacterial and fungal communities, and regulate the abundance of key functional microorganisms. This method effectively solves the problem of resource utilization and nitrogen loss of livestock and poultry manure, can improve compost quality, shorten the composting cycle, reduce environmental pollution, and promote resource recycling, with significant economic, social and environmental benefits.

[0004] The above object of the present invention is achieved through the following technical solutions:

[0005] A method for reducing nitrogen loss in a functional film covered aerobic composting system; comprising accurately dividing the spatial gradient of a pile, regulating microbial abundance, and regulating process indicators; performing gradient stratification according to the highest temperature of the pile in a high temperature stage to accurately regulate the temperature and oxygen concentration of each layer of the pile, thereby reducing nitrogen loss in the pile.

[0006] Furthermore, the spatial gradient of the pile is precisely divided: the specific layer height of the pile is divided according to the highest temperature gradient, and different layers are carefully regulated and analyzed. During the composting process, the temperature and oxygen content of the layers at different heights are monitored in real time. The gradient stratification divides the pile into 5 layers, with the first layer at the top and the fifth layer at the bottom. The first layer of the pile accounts for 5-15% of the pile height, meeting the maximum temperature of 75-78°C; the second layer accounts for 20-30% of the pile height, meeting the maximum temperature of 73-75°C; the third layer accounts for 15-25% of the pile height, meeting the maximum temperature of 71-73°C; the fourth layer accounts for 20-30% of the pile height, meeting the maximum temperature of 68-71°C; the fifth layer accounts for 25-35% of the pile height, meeting the maximum temperature of 66-68°C.

[0007] Furthermore, the regulation of microbial abundance includes sequencing 16S rRNA genes and ITS1 genes using high-throughput sequencing technology to analyze bacterial and fungal community composition and diversity. The relative abundance of Pseudomonas is increased to RA≥20%; the relative abundance of Oceanobacillus is increased to RA≥10%; the relative abundance of Aspergillus is increased to RA≥10%; the relative abundance of Bacillus is increased to RA≤5%; the relative abundance of Thermomyces is increased to RA≤5%; the relative abundance of Ignatzschineria is increased to RA≤20%, thereby reducing nitrogen loss in the pile.

[0008] Furthermore, the process control index includes comprehensively analyzing the temperature, oxygen content and microbial community composition data of each layer to control the oxygen concentration of the pile. The oxygen supply rate is set to 0.2L·kgTS-1·min-1 to 0.3L·kgTS-1·min-1, so that the oxygen concentration of the first layer of the pile is maintained between 13%-15%VOL; the oxygen concentration of the second layer of the pile is maintained between 10%-12%VOL; the oxygen concentration of the third layer of the pile is maintained between 12%-14%VOL; the oxygen concentration of the fourth layer of the pile is maintained between 14%-16%VOL; the oxygen concentration of the fifth layer of the pile is maintained between 16%-18%VOL.

[0009] The beneficial effects of the present invention compared with the prior art are:

[0010] The method provided by the present invention can effectively solve the problem of resource utilization of livestock and poultry manure, while reducing the loss of nitrogen in composting, and has considerable economic benefits, social benefits, and environmental benefits. This application achieves the purpose of reducing the loss of nitrogen in the pile by deeply exploring the changes in nitrogen in the FMCAC system and finely regulating the pile. Compared with the prior art, it also has the advantages of: 1) Improving the quality of compost: The present invention effectively reduces nitrogen loss through precise control of the composting process, significantly increases the nitrogen content in the compost product, improves the quality of fertilizer, and provides a better source of nutrients for crop growth. The composting process of this technology can promote microbial activity, accelerate the degradation of organic matter, make the compost more mature, and improve the stability and applicability of the compost. 2) Shorten the composting cycle: Accurately controlled composting parameters and reasonable process design accelerate the decomposition and transformation of organic matter in the composting process, shorten the time required for the compost to reach a mature state, improve the composting efficiency, and reduce the time cost. 3) Reduce environmental pollution: Effectively reduce the emission of harmful gases (such as NH3, N2O, etc.), reduce pollution to the atmospheric environment, reduce the greenhouse effect, and benefit environmental protection. Reasonable treatment of agricultural waste such as livestock manure avoids pollution of soil and water caused by random dumping or improper treatment of waste, and protects the ecological environment. 4) Promote resource recycling: Convert livestock manure and other waste into high-quality organic fertilizer products, realize the resource utilization of waste, reduce dependence on chemical fertilizers, and promote the virtuous cycle of agricultural ecosystems. It improves resource utilization, reduces waste treatment costs, and increases economic benefits, providing strong support for the sustainable development of agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is the FMCAC temperature analysis diagram in Example 1;

[0012] Figure 2 This is a diagram of the change of microbial communities in Example 1;

[0013] Figure 3 is the material balance diagram of FMCAC in Example 1;

[0014] Figure 4 It is a comparison chart of nitrogen loss between Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0015] Below in conjunction with the embodiment of the present invention, the technical scheme of the present invention is clearly and completely described, it is obvious that the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the scope of protection of the present invention. Unless otherwise specified, the equipment and reagents used in the present invention are conventional commercial products in the art.

[0016] The term "including" and its variations used in the present invention represent open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an exemplary embodiment" and "an embodiment" mean "at least one exemplary embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0017] Example 1

[0018] The method for reducing nitrogen loss in the aerobic composting system covered with a functional film provided by the present invention is specifically implemented as follows:

[0019] The project was carried out in a chicken farm in Dalian, Liaoning Province. According to the actual situation of the site, detailed planning was carried out, and composting tanks of appropriate specifications were designed and constructed. Two brick-concrete tanks with a length of 10m, a width of 6m, and a height of 1.5m were built, and one with a length of 10m, a width of 8m, and a height of 1.8m was built. The wall width was set to 20cm. The manure and straw of the farmed livestock and poultry were mixed in a precise ratio of 6:1 (wet weight) by weight and fully stirred. When the tank was full, the tank was tightly covered with a functional membrane to ensure good sealing of the tank. After 20 days of composting, the materials were emptied to mix the materials again and improve the fermentation quality. During the composting process, 250g of compost material samples were collected from sampling ports at different heights at a strict interval of every 2 days.

[0020] Figure 1The temperature changes of each layer of the pile were analyzed, and the specific layer heights of the pile were divided according to the highest temperature gradient: the first layer was at the top and the fifth layer was at the bottom. The first layer of the pile accounted for 5-15% of the pile height, meeting the maximum temperature of 75-78℃; the second layer accounted for 20-30% of the pile height, meeting the maximum temperature of 73-75℃; the third layer accounted for 15-25% of the pile height, meeting the maximum temperature of 71-73℃; the fourth layer accounted for 20-30% of the pile height, meeting the maximum temperature of 68-71℃; the fifth layer accounted for 25-35% of the pile height, meeting the maximum temperature of 66-68℃. Temperature can effectively reflect the aerobic composting process and affect the maturity of the compost. However, the temperature rise of different height layers of the compost was different. In general, affected by the external low temperature and ventilation, the compost temperature first rose sharply and then gradually decreased. The aeration volume of the trough is precisely regulated, and the oxygen supply rate is set to 0.2L·kgTS-1·min-1 to 0.3L·kgTS-1·min-1. The oxygen concentration of the first layer of the pile is maintained between 13%-15% VOL; the oxygen concentration of the second layer of the pile is maintained between 10%-12% VOL; the oxygen concentration of the third layer of the pile is maintained between 12%-14% VOL; the oxygen concentration of the fourth layer of the pile is maintained between 14%-16% VOL; and the oxygen concentration of the fifth layer of the pile is maintained between 16%-18% VOL.

[0021] According to the results of microbial community analysis, regulation was carried out according to the differences in the structure of microbial communities inside the compost body. During the composting process, the relative abundance of Pseudomonas RA≥20%; the relative abundance of Oceanobacillus RA≥10%; the relative abundance of Aspergillus RA≥10%; the relative abundance of Bacillus RA≤5%; the relative abundance of Thermomyces RA≤5%; and the relative abundance of Ignatzschineria RA≤20% were increased.

[0022] Figure 3The material balance and nitrogen and carbon changes of the FMCAC system in a composting cycle were analyzed in detail in the article. At the beginning of composting, a total of 48,400 kg of fresh chicken manure and 8,250 kg of wet weight straw were put in. The organic matter content of the fresh chicken manure put into the system was 9,189 kg, and the organic matter content of the straw was 7,012 kg. Under the action of microorganisms, a large amount of water, nitrogen-containing and carbon-containing gases were produced inside the tank. These gases were discharged from the composting system through aeration, causing material loss in the pile. The final output of the mature material had a wet weight of 29,400 kg and an organic matter content of 12,159 kg. Aerobic composting will lead to the emission of nitrogen-containing gases (NH3, N2O), resulting in nitrogen loss. Organic nitrogen is continuously mineralized and fixed during the composting process and converted into different forms of nitrogen. The total nitrogen content of the input compost mixture was 495 kg, and the total nitrogen content of the output mature material was 427 kg. The resulting nitrogen loss was 67 kg, and the nitrogen loss of the system was 13.64%. The contribution of different spatial layers in the pile to the overall nitrogen loss is 18.23%, 3.88%, 18.28%, 25.83% and 33.75% from the first to the fifth layers, respectively. The germination index (GI) is considered a key indicator of compost stability and phytotoxicity. A GI value of 80-85% indicates that the compost product is mature but may be phytotoxic. The GI values ​​of the first to the fifth layers of the compost are 84.19%, 100.26%, 96.04%, 86.06% and 71.5%, respectively. Through the above detailed spatial gradient research and control measures, the refined management of the membrane composting process is achieved, the nitrogen loss is minimized, and the quality and efficiency of the compost are improved.

[0023] Comparative Example 1

[0024] 1. The temperature and oxygen sensor probes are inserted into the pile to a depth of 40-60% for detection without detailed division detection.

[0025] 2. Accurately control the aeration volume of the tank, set the oxygen supply rate to 0.2L·kgTS-1·min-1 to 0.3L·kgTS-1·min-1, control the oxygen content of the pile between 10-20%VOL, and control the maximum temperature of the pile between 60-70℃.

[0026] 2. Collect samples using the same sampling method.

[0027] 3. Calculate the nitrogen loss rate of the system.

[0028] The nitrogen loss caused by the method provided in Example 1 and the common control method in the comparative example is compared and analyzed. Figure 4 It can be seen that the nitrogen loss rates of the two systems are 13.64% and 37.15% respectively. Fine control of the temperature, oxygen content and microbial community of the pile is effective in reducing nitrogen loss.

[0029] The above implementations are only preferred embodiments of the present invention. Without departing from the principles and spirit of the present invention, any obvious changes made thereto shall be deemed to be included in the scope of protection of the claims of the present invention. Those skilled in the art may appropriately adjust the process parameters, etc. according to actual conditions to achieve the best effect.

Claims

1. A method for reducing nitrogen loss in a functional membrane covered aerobic composting system, characterized in that: This includes accurately dividing the spatial gradient of the pile, regulating the abundance of microorganisms, and regulating process indicators; gradient stratification according to the highest temperature of the pile in the high-temperature stage to accurately regulate the temperature and oxygen concentration of each layer of the pile, thereby reducing nitrogen loss in the pile.

2. The method for reducing nitrogen loss in a functional membrane covered aerobic composting system according to claim 1, characterized in that: Accurately divide the spatial gradient of the pile: divide the specific layer height of the pile according to the highest temperature gradient, and conduct detailed regulation and analysis of different layers; during the composting process, monitor the temperature and oxygen content of layers at different heights in real time; divide the pile into 5 layers by gradient stratification, with the first layer at the top and the fifth layer at the bottom; the first layer of the pile accounts for 5-15% of the pile height and meets the maximum temperature of 75-78℃; the second layer accounts for 20-30% of the pile height and meets the maximum temperature of 73-75℃; the third layer accounts for 15-25% of the pile height and meets the maximum temperature of 71-73℃; the fourth layer accounts for 20-30% of the pile height and meets the maximum temperature of 68-71℃; the fifth layer accounts for 25-35% of the pile height and meets the maximum temperature of 66-68℃.

3. The method for reducing nitrogen loss in a functional membrane covered aerobic composting system according to claim 1, characterized in that: Regulation of microbial abundance includes sequencing the 16S rRNA gene and ITS1 gene using high-throughput sequencing technology to analyze the composition and diversity of bacterial and fungal communities; increasing the relative abundance of Pseudomonas RA ≥ 20%; the relative abundance of Oceanobacillus RA ≥ 10%; the relative abundance of Aspergillus RA ≥ 10%; the relative abundance of Bacillus RA ≤ 5%; the relative abundance of Thermomyces RA ≤ 5%; and the relative abundance of Ignatzschineria RA ≤ 20%.

4. The method for reducing nitrogen loss in a functional membrane covered aerobic composting system according to claim 1, characterized in that: The control process indicators include: comprehensively analyzing the temperature, oxygen content and microbial community composition data of each layer, and controlling the oxygen concentration of the pile; the oxygen supply rate is set at 0.2L·kg TS-1·min-1 to 0.3L·kgTS-1·min-1, the oxygen concentration of the first layer of the pile is maintained between 13%-15% VOL; the oxygen concentration of the second layer of the pile is maintained between 10%-12% VOL; the oxygen concentration of the third layer of the pile is maintained between 12%-14% VOL; the oxygen concentration of the fourth layer of the pile is maintained between 14%-16% VOL; the oxygen concentration of the fifth layer of the pile is maintained between 16%-18% VOL.

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