A livestock and poultry manure black film fermentation resource method and system based on composite flora immobilization and micro-oxygen control

Abstract

The application provides a livestock and poultry manure black film fermentation resourceization method and system based on composite microbial flora immobilization and micro-oxygen control, and belongs to the technical field of livestock and poultry manure resourceization utilization and environmental engineering. The system comprises a fermentation tank, a fermentation liquid discharge pipe, a sewage pipe and an oxygen increasing assembly connected to the fermentation tank, a black film installed on the inner wall of the fermentation tank, a suspension assembly installed on the top of the fermentation tank, and a plurality of bag bodies suspended on the suspension assembly, wherein the bag bodies are filled with a mixture of composite immobilized microbial inoculum and soil, h2 / h1=0.3-0.75 is satisfied between the bag body and the fermentation tank, and the bag body is located below the livestock and poultry manure liquid level in the fermentation tank. The system has the advantages of short fermentation period, high harmless degree of fermentation liquid, low nitrogen loss rate and no obvious odor.

Description

Technical Field

[0001] This invention relates to the fields of livestock and poultry manure resource utilization and environmental engineering technology, and in particular to a method and system for the resource utilization of livestock and poultry manure through black film fermentation based on the immobilization of composite microbial communities and micro-aerobic control. Background Technology

[0002] With the large-scale and intensive development of livestock and poultry farming, the amount of livestock waste generated has increased significantly. Among these, the treatment and disposal of liquid manure has become a prominent issue restricting the sustainable development of the industry. Taking pig farming as an example, as feed becomes more refined, the solid content in manure decreases, making solid-liquid separation more difficult. A large amount of organic matter and nitrogen and phosphorus nutrients accumulate in the liquid phase. Improper treatment not only wastes resources but also easily leads to environmental problems such as eutrophication of water bodies, soil compaction, and foul odors disturbing residents.

[0003] Currently, liquid manure treatment mainly employs two technical routes: black film biogas fermentation and aerobic fermentation in oxidation ponds. Black film biogas fermentation involves laying HDPE black film in an excavated pit to form an anaerobic fermentation tank. The black film absorbs heat to raise the fermentation temperature, and anaerobic microorganisms convert organic matter into biogas. This technology has low investment and simple construction, and has been used to some extent in livestock farms. However, in practice, black film biogas fermentation has the following shortcomings: First, the fermentation cycle is long, requiring 60-90 days in summer and over 120 days in winter, making it difficult to match the processing efficiency with the needs of expanding livestock farming scale; second, the organic matter in the biogas slurry is not completely degraded, leaving a large amount of large-molecule proteins and cellulose residues, which can easily cause soil pore blockage, leading to crop burn and soil compaction if used directly in agriculture; third, biogas production is greatly affected by temperature, and with the adjustment of rural energy structure, the local utilization of biogas is limited. Aerobic fermentation in oxidation ponds, on the other hand, uses aeration equipment to oxygenate the manure, utilizing aerobic microorganisms to rapidly degrade organic matter. The technology has a relatively short treatment cycle, but it has obvious drawbacks: First, continuous aeration has high energy consumption, with power consumption of 1.5-3.0 kWh per ton of water treated, resulting in high operating costs; second, excessive aeration leads to the stripping and volatilization of a large amount of ammonia nitrogen in the sewage, which not only produces malodorous gases that pollute the environment, but also causes nitrogen nutrient loss, with measured ammonia loss rates reaching 40%-60%; third, the carbon dioxide generated during the treatment process is directly released into the atmosphere, without achieving resource recovery.

[0004] To address the aforementioned technical shortcomings, researchers have attempted to enhance treatment effectiveness by adding exogenous microorganisms to the fermentation system. One approach involves directly adding a compound bacterial solution to the fermentation tank and maintaining bacterial activity through periodic replenishment. In this approach, the bacteria exist in a free state, resulting in a high rate of loss with the influent and effluent flow, making it difficult to maintain an effective bacterial concentration in the tank for extended periods, necessitating periodic replenishment. Another approach uses immobilization technology to encapsulate or adsorb microorganisms onto carrier materials to prolong bacterial retention time. However, existing immobilization carriers often employ artificial materials such as polymer gels, which are costly and have long natural degradation cycles, limiting their practical application. Furthermore, none of the above approaches systematically match the fermentation tank structure, aeration methods, and immobilized bacterial agents. Targeted optimization methods have not yet been established for key parameters such as the location of bacterial agent addition and the dissolved oxygen control range, limiting the improvement in treatment effectiveness.

[0005] Therefore, how to stably retain highly efficient degrading bacteria in the fermentation system while simultaneously optimizing processing efficiency, energy consumption control, and nutrient resource recovery remains a pressing technical problem to be solved in this field. Summary of the Invention

[0006] To address the issues of long fermentation cycles, incomplete organic matter degradation, high energy consumption for aerobic aeration, and significant nitrogen loss associated with black film biogas fermentation, this invention provides a method and system for the resource utilization of livestock and poultry manure through black film fermentation based on the immobilization of a composite microbial community and microaerobic control. The system of this invention can achieve efficient degradation of manure, odor suppression, and full resource utilization of fermentation products.

[0007] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is a black film fermentation system for livestock and poultry manure based on immobilized composite microbial communities and micro-aerobic control, characterized in that it includes: A fermentation tank, which is connected to a fermentation liquid discharge pipe, a sewage pipe and an oxygenation component; A black film is installed on the inner wall of the fermentation tank; A suspension assembly, which is installed on top of the fermentation tank; The bag body is provided in several parts and is suspended on the suspension assembly; the bag body contains a mixture of composite immobilized microbial agent and soil; wherein, the distance between the bag body and the fermentation tank satisfies h2 / h1=0.3~0.75, where h1 is the height of the fermentation tank, h2 is the distance between the bottom of the bag body and the bottom wall of the fermentation tank, and the bag body is located below the surface of the livestock and poultry manure liquid in the fermentation tank.

[0008] Preferably, the preparation method of the composite immobilized microbial agent is as follows: Step 1. Bacillus subtilis, Aspergillus oryzae, Aspergillus niger, yeast, lactic acid bacteria and denitrifying bacteria are cultured in liquid culture separately, and then the fermentation broths of each strain are mixed to obtain a mixed fermentation broth; Step 2. Activate and culture the mixed fermentation broth; Step 3. After the activation culture is completed, the mixture is inoculated into a mixture of corn cob, corn flour and soybean flour for fermentation.

[0009] More preferably, in step 1, when mixing the fermentation broths of each microorganism, the volume ratio of each fermentation broth is: Bacillus subtilis fermentation broth: Aspergillus oryzae fermentation broth: Aspergillus niger fermentation broth: yeast fermentation broth: lactic acid bacteria fermentation broth: denitrifying bacteria fermentation broth = (2.5-3.0): (2.0-2.5): (2.0-2.5): (1.0-1.5): (0.5-1.0): (1.0-2.5), wherein the concentration of Bacillus subtilis in the Bacillus subtilis fermentation broth is 10. 8 -10 9 The concentration of Aspergillus oryzae fermentation broth was 10 CFU / mL. 7 -10 8 The concentration of Aspergillus niger fermentation broth was 10 CFU / mL. 7 -10 8 CFU / mL, the concentration of the yeast fermentation broth is 10. 8 -10 9 The concentration of the lactic acid bacteria fermentation broth is 10 CFU / mL. 8 -10 9 The concentration of denitrifying bacteria fermentation broth is 10 CFU / mL. 8 -10 9 CFU / mL.

[0010] More preferably, in step 2, the culture medium used for activation culture is a grain matrix with a total sugar content of 5%-8%; the activation culture temperature is 28-32℃ and the time is 24h.

[0011] More preferably, in step 3, the carbon-to-nitrogen ratio of the mixture is 20:1-35:1; the mass ratio of corn cob, corn flour, and soybean flour is (2-3):(4.8-5.6):(1.4-3.2), wherein the particle size of corn cob, corn flour, and soybean flour is 50-100 mesh; before fermentation, the step further includes adjusting the moisture content of the mixture to 60%-65%; after fermentation, the inoculum cell load is ≥10. 9 CFU / g mixture.

[0012] Preferably, the mass ratio of the composite immobilized microbial agent to the soil is (1-1.5):(1.5-2).

[0013] Preferably, the suspension assembly includes: A ring beam, which is located on the top surface of the fermentation tank; A suspension rod is fixedly connected to the ring beam; wherein, a plurality of the bags are hung on the suspension rod by suspension ropes.

[0014] Preferably, the oxygenation component includes an air inlet pipe, an oxygenation pump, and a microporous aeration disc located at the bottom of the fermentation tank. The oxygenation pump is installed on the fermentation tank and is connected to the inner cavity of the fermentation tank through the air inlet pipe.

[0015] Preferably, the cross-section of the fermentation tank is formed as an inverted isosceles trapezoid, and the included angle of the inverted isosceles trapezoid is 65°~75°; A wall is installed on one side of the top surface of the fermentation tank, and an observation port is provided on the wall; A CO2 exhaust pipe is installed on the wall; The fermentation tank is equipped with a roof, which is located above the ring beam and the wall.

[0016] The second technical solution of the present invention is a method for fermenting livestock and poultry manure based on immobilization of composite microbial communities and micro-oxygen control, which utilizes the above-mentioned black film fermentation system for livestock and poultry manure to ferment livestock and poultry manure; during the fermentation process, the concentration of dissolved oxygen is 0.2~0.5 mg / L.

[0017] The livestock and poultry manure black film fermentation system of the present invention has the following technical advantages: (1) Shortened fermentation cycle: 30-40 days in summer and 60-90 days in winter, which is about 60% shorter than the traditional black film biogas fermentation cycle; (2) The fermentation liquid has a high degree of harmlessness: the seed germination index is ≥95%, which meets the standard for harmless organic fertilizer; (3) Low nitrogen loss rate: controlled within 15%, which is more than 60% lower than conventional aeration treatment; (4) Odor control: There is no obvious ammonia or hydrogen sulfide odor during the fermentation process; (5) Resource utilization: Fermentation liquid is used as liquid fertilizer and CO2 is used as gas fertilizer to realize carbon and nitrogen resource recycling. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the structure of the livestock and poultry manure black film fermentation system of the present invention; wherein, 1, fermentation tank body, 2, roof, 3, suspension rod, 4, ring beam, 5, observation port, 6, CO2 exhaust pipe, 7, sewage pipe, 8, liquid inlet, 9, liquid level line, 10, bag body, 11, black film, 12, mud layer, 13, fermentation liquid discharge pipe, 14, fermentation liquid discharge outlet, 15, fermentation tank slope 65-75°, 16, air pipe, 17, oxygen pump, 18, oxygen pump switch, 19, orchard; Figure 2 This is a graph showing the changes in seed germination index under different dissolved oxygen levels in Example 1 and Comparative Example 4. Figure 3 This is a comparison chart showing the dynamic changes in pH and ammonia nitrogen concentration during the fermentation process of Example 1 and Comparative Example 1. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] In this invention, unless otherwise specified, "%" represents the mass percentage.

[0026] To address the dual technical contradictions of existing black film biogas fermentation, such as long fermentation cycle and incomplete degradation, as well as high energy consumption and significant nitrogen loss in aerobic aeration, this invention provides a method and system that achieves efficient degradation of manure, odor elimination, and full resource utilization of water, fertilizer, and gas through the synergistic effect of composite microbial community immobilization and micro-aerobic control.

[0027] The core of this invention lies in constructing a synergistic fermentation system integrating a specific composite immobilized microbial community, a microaerobic environment, and a suitable tank structure. First, various functional microorganisms with complementary metabolic relationships are screened, compounded, and inoculated onto an optimized porous composite carrier for solid-state fermentation, forming an immobilized microbial agent with a three-dimensional microbial community structure. Second, this immobilized microbial agent is suspended in a specific liquid phase region of an inverted trapezoidal black film fermentation tank. Third, precise control of microaerobic aeration induces synergistic metabolism within the microbial community. Finally, a gas collection system at the top of the tank actively collects and transports the carbon dioxide produced during fermentation to the orchard as gaseous fertilizer, while the fermentation broth serves as liquid fertilizer.

[0028] This invention provides a black film fermentation system for livestock and poultry manure based on immobilized composite microbial communities and micro-aerobic control, comprising: A fermentation tank, which is connected to a fermentation liquid discharge pipe, a sewage pipe and an oxygenation component; A black film is installed on the inner wall of the fermentation tank; A suspension assembly, which is installed on top of the fermentation tank; The bag body is provided in several parts and is suspended on the suspension assembly; the bag body contains a mixture of composite immobilized microbial agent and soil; wherein, the distance between the bag body and the fermentation tank satisfies h2 / h1=0.3~0.75, where h1 is the height of the fermentation tank, h2 is the distance between the bottom of the bag body and the bottom wall of the fermentation tank, and the bag body is located below the surface of the livestock and poultry manure liquid in the fermentation tank.

[0029] In this invention, the suspension assembly includes: A ring beam, which is located on the top surface of the fermentation tank; A suspension rod is fixedly connected to the ring beam; wherein, a plurality of the bags are hung on the suspension rod by suspension ropes; The oxygenation assembly includes an air inlet pipe, an oxygenation pump, and a microporous aeration disc located at the bottom of the fermentation tank. The oxygenation pump is installed on the fermentation tank and is connected to the inner cavity of the fermentation tank through the air inlet pipe. The cross-section of the fermentation tank is formed as an inverted isosceles trapezoid, with the included angle of the inverted isosceles trapezoid being 65°~75°; A wall is installed on one side of the top surface of the fermentation tank, and an observation port is provided on the wall; A CO2 exhaust pipe is installed on the wall; The fermentation tank is equipped with a roof, which is located above the ring beam and the wall.

[0030] As an example, such as Figure 1 As shown, on a flat open space, dig an inverted trapezoidal high-efficiency fermentation tank for manure and sewage, 4.0-5.0m deep, with a volume matching the waste treatment capacity. The included angle of the trapezoid should be 65°-75°. A black membrane should be smoothly welded to the inner side and bottom of the fermentation tank, ensuring complete seams and preventing leakage of manure and sewage. A ring beam with pre-embedded hooks should be cast along the edge of the fermentation tank, and a suspension rod should be fixedly connected to the ring beam. Several bags should be hung on the suspension rod via suspension ropes. A wall with pre-reserved observation holes should be built on one side of the fermentation tank, and a CO2 exhaust pipe should be installed on the wall to periodically discharge CO2, achieving full utilization of manure, sewage, gas, and solid fertilizer. The fermentation tank is also connected to a fermentation liquid discharge pipe, a sewage pipe, and an aeration assembly. The aeration assembly includes an air duct, an aeration pump, and a microporous aeration disc located at the bottom of the fermentation tank. The aeration pump is installed on the fermentation tank and connected to the inner cavity of the fermentation tank through the air duct. Install an oxygenation pump to increase the oxygen content of the fermentation broth, creating conditions for aerobic and facultative aerobic microorganisms and accelerating the degradation of fecal waste. Erect a canopy (such as a 2-2.5mm thick PVC polymer material with ropes) above the ring beam and walls.

[0031] When fermenting livestock and poultry manure, place the manure into the fermentation tank, ensuring the height is 20-30 cm below the exhaust pipe and submerges the bags. Regularly turn on the aeration pump to control dissolved oxygen at 0.2-0.5 mg / L. In summer, after 30-40 days, the fermentation liquid will be clear and transparent, with a seed germination index ≥95%. In winter, after 60-90 days, the fermentation liquid will be clear and transparent, with a seed germination index ≥90% (germination index = number of germinated seeds / total number of seeds).

[0032] In this invention, the bag contains a mixture of composite immobilized microbial agent and soil.

[0033] In a preferred embodiment of the present invention, the preparation method of the composite immobilized microbial agent is as follows: Step 1. Bacillus subtilis, Aspergillus oryzae, Aspergillus niger, yeast, lactic acid bacteria and denitrifying bacteria are cultured in liquid culture separately, and then the fermentation broths of each strain are mixed to obtain a mixed fermentation broth; Step 2. Activate and culture the mixed fermentation broth; Step 3. After the activation culture is completed, the mixture is inoculated into a mixture of corn cob, corn flour and soybean flour for fermentation.

[0034] More preferably, in step 1, during liquid culture, Bacillus subtilis, lactic acid bacteria, and denitrifying bacteria are cultured on LB liquid medium, while Aspergillus oryzae, Aspergillus niger, and yeast are cultured on PDA liquid medium. The culture temperature is 28℃~32℃, and the culture time is 24~48h. When mixing the fermentation broths of each strain, the volume ratio of each strain's fermentation broth is: Bacillus subtilis fermentation broth : Aspergillus oryzae fermentation broth : Aspergillus niger fermentation broth : yeast fermentation broth : lactic acid bacteria fermentation broth : denitrifying bacteria fermentation broth = (2.5-3.0) : (2.0-2.5) : (2.0-2.5) : (1.0-1.5) : (0.5-1.0) : (1.0-2.5), wherein the concentration of Bacillus subtilis in the Bacillus subtilis fermentation broth is 10. 8 -10 9 The concentration of Aspergillus oryzae fermentation broth was 10 CFU / mL. 7 -10 8 The concentration of Aspergillus niger fermentation broth was 10 CFU / mL. 7 -10 8 CFU / mL, the concentration of the yeast fermentation broth is 10. 8 -10 9 The concentration of the lactic acid bacteria fermentation broth is 10 CFU / mL. 8 -10 9 The concentration of denitrifying bacteria fermentation broth is 10 CFU / mL. 8 -10 9 CFU / mL.

[0035] More preferably, in step 2, the culture medium used for activation culture is a grain substrate with a total sugar content of 5%-8%; the activation culture temperature is 28-32℃, and the time is 24h. As an example, the grain substrate with a total sugar content of 5%-8% is steamed rice porridge cooled to room temperature, the solid-liquid ratio of the rice porridge is 1:5, and the total sugar content is 5%-8%.

[0036] More preferably, in step 3, the carbon-to-nitrogen ratio of the mixture is 20:1-35:1; the mass ratio of corn cob, corn flour, and soybean flour is (2-3):(4.8-5.6):(1.4-3.2), wherein the particle size of corn cob, corn flour, and soybean flour is 50-100 mesh; before fermentation, the mixture is further adjusted to a moisture content of 60%-65%; during fermentation, the mixture is covered with plastic film, the four corners are compacted, and the mixture is turned over once when the temperature rises to 55℃~60℃, until the surface of the mixture is covered with mycelium, which constitutes the composite immobilized microbial agent; after fermentation, the inoculum loading is ≥10. 9 CFU / g mixture.

[0037] In this invention, corn flour and soybean flour primarily provide nutrients for the growth and development of microorganisms, enhancing their adaptability, shortening the adaptation period, and extending the logarithmic growth phase. Corn cobs have numerous pores, resulting in a strong ability to adsorb / immobilize microorganisms.

[0038] In a preferred embodiment of the present invention, the mass ratio of the composite immobilized microbial agent to the soil is (1-1.5):(1.5-2).

[0039] The second aspect of this invention provides a method for fermenting livestock and poultry manure based on immobilized composite microbial communities and micro-oxygen control, which utilizes the aforementioned black film fermentation system for livestock and poultry manure fermentation; during the fermentation process, the concentration of dissolved oxygen is 0.2~0.5 mg / L.

[0040] This invention achieves efficient fermentation and utilization of livestock and poultry manure through the following mechanism: 1. Metabolic complementarity and synergistic mechanisms of complex microbial communities The bacterial strains selected in this invention have complementary metabolic functions. Bacillus subtilis secretes proteases and amylases to initially break down proteins and starches; Aspergillus oryzae and Aspergillus niger further degrade polypeptides and cellulose, generating small-molecule amino acids and monosaccharides; yeast utilizes monosaccharides for metabolic transformation; lactic acid bacteria produce acid to regulate the system's pH and fix ammonia nitrogen; denitrifying bacteria convert ammonia into nitrate nitrogen, eliminating odors. These bacterial strains work synergistically to form a complete degradation and transformation chain; the absence of any one strain will lead to a decrease in treatment efficiency.

[0041] 2. Selective adaptation of the carrier Corn cobs, after being pulverized to 50-100 mesh, form a porous structure that can efficiently adsorb and immobilize microorganisms. Corn flour provides a readily available carbon source, and soybean flour provides a readily available nitrogen source. When mixed in a specific ratio, the carbon-to-nitrogen ratio is controlled at 20-35:1, providing nutritional conditions for the initial colonization of the microbial community. The pore size distribution of this composite carrier exhibits a gradient characteristic, simultaneously accommodating aerobic, facultative, and anaerobic bacteria to form a three-dimensional microbial community structure, which is compatible with subsequent microaerobic control.

[0042] 3. Optimized design of bag suspension position The distance between the bag and the fermentation tank satisfies h2 / h1=0.3~0.75, where h1 is the height of the fermentation tank and h2 is the distance between the bottom of the bag and the bottom wall of the fermentation tank. The bag is located below the surface of the livestock and poultry manure liquid in the fermentation tank, based on the following considerations: For example, when the height of the fermentation tank is 4-5m, the immobilized bacterial agent is suspended in the liquid phase region 1.5-3.0m from the bottom of the tank.

[0043] Through simulation measurements of the temperature and dissolved oxygen fields inside the inverted trapezoidal black film fermentation tank, it was found that; The bottom 0-1.5m area of ​​the pool: sediment accumulation, dissolved oxygen <0.1mg / L, strictly anaerobic, mainly undergoing methane production reaction; The area with a depth of 1.5-3.0m is located in the main liquid phase circulation zone, with dissolved oxygen of 0.2-0.5mg / L, exhibiting a micro-aerobic state, and the temperature is relatively stable (3-5℃ higher than the bottom of the pool due to the heat absorption of the black film). The area from the pool depth of 3.0m to the liquid surface: close to the black film covering layer, where temperature fluctuations are large and gas escape is intense.

[0044] Suspending the bacterial agent in the 1.5-3.0m range avoids the inactivation of bacteria caused by the strict anaerobic environment at the bottom of the pool, and also avoids the damage to the bacterial agent caused by surface temperature fluctuations and gas erosion, thus keeping the immobilized bacteria in the optimal "micro-oxygen-constant temperature" working range.

[0045] 4. Precise control of dissolved oxygen The dissolved oxygen range of 0.2-0.5 mg / L is not arbitrarily chosen (see Table 1 for details). Within this range: Aerobic bacteria (Bacillus subtilis, Aspergillus oryzae, Aspergillus niger) maintain activity and efficiently secrete extracellular hydrolases; facultative bacteria (yeast, lactic acid bacteria, denitrifying bacteria) are metabolically active, completing secondary transformations and nitrogen fixation; the activity of obligate anaerobic methanogens is effectively inhibited, shifting the organic carbon flow from methane (difficult to utilize) to smaller organic molecules and CO2 (easily recycled); ammonia volatilization rate is lowest, and nitrogen retention rate is highest (>85%). When dissolved oxygen <0.2 mg / L, anaerobic bacteria dominate, the fermentation cycle is prolonged, and odor is produced; when dissolved oxygen >0.5 mg / L, aerobic bacteria are overactive, ammonia volatilization intensifies, and energy consumption increases.

[0046] Table 1 Comparison of fermentation effects under different dissolved oxygen levels

[0047] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0048] In this invention, the seed germination index is determined according to the GB / T 39234-2020 standard.

[0049] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0050] Example 1 Shaanxi Chengcheng Demonstration Project (1) Preparation of composite immobilized microbial agents Bacillus subtilis, lactic acid bacteria, and denitrifying bacteria were cultured on LB liquid medium, while Aspergillus oryzae, Aspergillus niger, and yeast were cultured on PDA liquid medium at 31°C with stirring for 30 hours. The fermentation broths of each strain were then mixed at a volume ratio of 2.5:2.0:2.0:1.0:0.5:2.5, with the Bacillus subtilis fermentation broth concentration being 10%. 8 -10 9 The concentration of Aspergillus oryzae fermentation broth was 10 CFU / mL. 7 -10 8 The concentration of Aspergillus niger fermentation broth was 10 CFU / mL. 7 -10 8 CFU / mL, the concentration of the yeast fermentation broth is 10. 8 -10 9 The concentration of the lactic acid bacteria fermentation broth is 10 CFU / mL. 8 -10 9 The concentration of denitrifying bacteria fermentation broth is 10 CFU / mL. 8 -10 9 Take 150 kg of the CFU / mL mixture and add it to porridge that has been washed, steamed, and cooled to room temperature (the porridge has a solid-liquid ratio of 1:5, a total sugar content of 8%, and is placed in a plastic bucket, not exceeding 2 / 3 of its volume). Mix thoroughly and activate at 30℃ for 24 hours, stirring every 2 hours. After activation, add the material to a mixture of corn cobs, corn flour, and soybean flour (all with a particle size of 80 mesh, a mass ratio of 2:4.8:2.0, and a carbon-nitrogen ratio of 28:1), adjust the moisture content to 60%, and pile the mixture into a 60 cm high heap. Cover with plastic film and compact the four corners. When the heap temperature rises to 55℃, turn the heap once and continue fermentation until the surface is covered with mycelium, thus obtaining the composite immobilized microbial agent.

[0051] (2) Construction of black film fermentation system Select a flat, open site 1.0 km from the breeding farm, and dig a pit 4.5 m deep with a volume of 800 m³. 3 The fermentation tank is an inverted trapezoidal structure with its walls forming a 70° angle with the horizontal plane. The black membrane is smoothly welded to the inner side and bottom of the tank using welding technology, ensuring a clean and leak-free joint. The tank perimeter is compacted, and a 20cm high hooked ring beam is poured 45cm from the edge. An 80cm high wall is built 30cm from the edge of the tank side, with a 20×20cm observation hole provided.

[0052] Mix the above-mentioned microbial agent with soil at a mass ratio of 1:2 and fill the mixture into breathable woven bags. Erect bamboo poles spaced 65cm apart on top of the pool, attaching four woven bags to each pole, suspending them in the liquid phase area 3.0m above the pool bottom. Install an oxygen pump and aeration pipes at the bottom of the pool. Cover the pool with a 2mm thick PVC polymer film, secured with ropes to a hooked ring beam. Install an exhaust pipe below the film, with the outlet 20cm above the normal liquid level, connecting to a neighboring orchard.

[0053] (3) Fermentation treatment Liquid manure from the pig farm is injected, with the liquid level submerging the woven bag and 20cm below the exhaust pipe. Dissolved oxygen is controlled at 0.2-0.5mg / L using an aerator. Fermentation takes 35 days in summer, resulting in a clear and transparent fermentation liquid with a seed germination rate of 97%; fermentation takes 90 days in winter, resulting in a seed germination rate of 94%.

[0054] (4) Resource utilization After fermentation, the clear liquid from the top of the fermentation tank was taken, diluted with water at a volume ratio of 1:100, and then sprayed on the leaves during the corn silking stage (approximately 50 kg per acre). A control group of the same variety and from the same plot was used, with all other field management practices maintained consistently. Corn yield: The example group yielded 658 kg / acre, while the control group yielded 530 kg / acre, representing an increase of 128 kg / acre.

[0055] During fermentation, the exhaust pipe was opened periodically to transport the collected CO2 to neighboring orchards. Compared with the control area where no CO2 was introduced, the incidence of downy mildew in the example area was 12.5%, while it was 24.7% in the control area, a decrease of 49.5%. The soluble solids content of grapes in the example area was 18.5%, while it was 16.8% in the control area, an increase of 10.1%. The amino acid content in the example area was 0.62 mg / g, while it was 0.57 mg / g in the control area, an increase of 8.8%. The vitamin C content in the example area was 5.2 mg / 100g, while it was 4.7 mg / 100g in the control area, an increase of 10.6%.

[0056] Example 2 Xianyang Binzhou Demonstration Project (1) Preparation of composite immobilized microbial agents Bacillus subtilis, lactic acid bacteria, and denitrifying bacteria were cultured on LB liquid medium, while Aspergillus oryzae, Aspergillus niger, and yeast were cultured on PDA liquid medium. All cultures were incubated at 30°C with stirring for 36 hours. The fermentation broths of each strain were then mixed at a volume ratio of 3.0:2.0:2.0:1.0:1.5, with the Bacillus subtilis fermentation broth concentration being 10%. 8 -10 9 The concentration of Aspergillus oryzae fermentation broth was 10 CFU / mL. 7 -10 8 The concentration of Aspergillus niger fermentation broth was 10 CFU / mL. 7 -10 8 CFU / mL, the concentration of the yeast fermentation broth is 10. 8 -10 9 The concentration of the lactic acid bacteria fermentation broth is 10 CFU / mL. 8 -10 9 The concentration of denitrifying bacteria fermentation broth is 10 CFU / mL.8 -10 9 Take 200 kg of the CFU / mL mixture and add it to porridge that has been washed, steamed, and cooled to room temperature (the porridge has a solid-liquid ratio of 1:5, a total sugar content of 8%, and is placed in a plastic bucket, not exceeding 2 / 3 of its volume). Mix thoroughly and activate at 30℃ for 24 hours, stirring every 1.5 hours. After activation, add the material to a mixture of corn cobs, corn flour, and soybean flour (all with a particle size of 100 mesh, a mass ratio of 2.5:5:2.5, and a carbon-nitrogen ratio of 30:1), adjust the moisture content to 62%, and pile the mixture into a 70 cm high heap. Cover with plastic film and compact the four corners. When the heap temperature rises to 60℃, turn the heap once and continue fermentation until the surface is covered with mycelium, thus obtaining the composite immobilized microbial agent.

[0057] (2) Construction of black film fermentation system Select a flat, open site 1.5km from the breeding farm, and dig a pit 5.0m deep with a volume of 1200m³. 3 The fermentation tank is an inverted trapezoidal structure with its walls at a 75° angle to the horizontal. A black membrane is smoothly welded to the inner side and bottom of the tank using welding technology, ensuring a seamless and leak-free joint. The tank perimeter is compacted, and a 20cm high hooked ring beam is poured 50cm from the edge. A 70cm high wall is built 30cm from the edge of the tank side, with a 20×20cm observation hole pre-drilled. The above-mentioned microbial agent is mixed with soil at a mass ratio of 1.5:2 and filled into breathable woven bags. Bamboo poles are erected on the tank roof, spaced 65cm apart, with three woven bags attached to each pole, suspended in the liquid phase area 2.5m from the bottom. An oxygen pump and aeration pipes are installed at the bottom of the tank. A 2mm thick PVC polymer covering film is laid on top of the tank, secured to the hooked ring beam with ropes. An exhaust pipe is installed below the covering film, with the outlet 20cm above the normal liquid level, connecting to a nearby orchard.

[0058] (3) Fermentation treatment Liquid manure from the pig farm is injected, with the liquid level submerging the woven bag and 20cm below the exhaust pipe. Dissolved oxygen is controlled at 0.2-0.5mg / L using an aerator. Fermentation takes 35 days in summer, resulting in a clear and transparent fermentation liquid with a seed germination rate of 98%; fermentation takes 90 days in winter, resulting in a seed germination rate of 93%.

[0059] (4) Resource utilization Take the clear liquid from the top of the fermentation tank, dilute it with water at a ratio of 1:100, and apply it to the roots during the bud break and fruit expansion stages (approximately 200 kg per acre). Apply it to the leaves before flowering and during the color change stage (approximately 50 kg per acre). Use grapes of the same variety and age that are treated with the same amount of water as a control, and keep other field management practices consistent.

[0060] The incidence of grape downy mildew was 15.8% in the example group and 29.5% in the control group, a decrease of approximately 46.5%; soluble solids content was 17.2% in the example group and 15.6% in the control group, an increase of approximately 10.3%; amino acid content was 0.58 mg / g in the example group and 0.53 mg / g in the control group, an increase of approximately 9.4%; vitamin C content was 4.9 mg / 100g in the example group and 4.4 mg / 100g in the control group, an increase of approximately 11.4%; after two consecutive growing seasons of application, no soil compaction or leaf scorching was observed.

[0061] Comparative Example 1 Comparison of effects between single strain and compound strain To verify the synergistic effect of the bacterial community combination, Comparative Example 1 was set up: only Bacillus subtilis and Aspergillus oryzae were used, and the other conditions were the same as in Example 1.

[0062] Results: By day 15 of fermentation, the pH had risen to 8.7, with a strong ammonia odor. The fermentation period was extended to 55 days, and the seed germination index was only 76%. This indicates that the absence of lactic acid bacteria and denitrifying bacteria hindered nitrogen conversion, caused pH imbalance, and resulted in the production of unpleasant odors.

[0063] Comparative Example 2 Carrier optimization comparison To verify the selective adaptation of the carrier, Comparative Example 2 was set up: all strains of the present invention were used, but the carrier was changed to rice husk (80 mesh), and the other conditions were the same as in Example 1.

[0064] Results: The bacterial load decreased by 35% compared to Example 1, fermentation start was delayed by 48 hours, and the final fermentation cycle was extended to 48 days. This indicates that the porous structure of corn cobs and the nutrient supply from corn flour and soybean flour are crucial for bacterial colonization.

[0065] Comparative Example 3 Comparison of bacterial agent suspension positions To verify the accuracy of the suspension position, Comparative Example 3 was set up: the woven bag was submerged to the bottom of the pool (0m from the bottom of the pool), and the other conditions were the same as in Example 1.

[0066] Results: The fermentation period was extended to 52 days, the bottom of the fermentation liquid turned black and smelly, and the seed germination index was 79%. This indicates that the strictly anaerobic environment at the bottom of the tank led to the inactivation of some bacteria and the proliferation of anaerobic putrefactive bacteria.

[0067] Comparative Example 4 Dissolved oxygen range comparison (1) Dissolved oxygen control <0.1mg / L, other conditions are the same as in Example 1.

[0068] Results: The fermentation period was extended to 75 days, the seed germination index was 72%, the nitrogen loss rate was 15%, and the ammonia odor was strong.

[0069] (2) Dissolved oxygen is controlled at 0.6-1.0 mg / L, and the other conditions are the same as in Example 1.

[0070] Results: The fermentation cycle was shortened to 28 days, the seed germination index was 96%, the nitrogen loss rate was 28%, and the ammonia odor was weak.

[0071] (3) Dissolved oxygen is controlled at 1.0-2.0 mg / L, and the other conditions are the same as in Example 1.

[0072] Results: The fermentation cycle was shortened to 25 days, the seed germination index was 93%, the nitrogen loss rate was 41%, and the ammonia odor intensity was moderate.

[0073] Example 1 and Comparative Example 4 demonstrate that 0.2-0.5 mg / L is the optimal range.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A black film fermentation system for livestock and poultry manure based on immobilized composite microbial communities and micro-aerobic control, characterized in that, include: A fermentation tank, which is connected to a fermentation liquid discharge pipe, a sewage pipe and an oxygenation component; A black film is installed on the inner wall of the fermentation tank; A suspension assembly, which is installed on top of the fermentation tank; The bag body is provided in several parts and is suspended on the suspension assembly; the bag body contains a mixture of composite immobilized microbial agent and soil; wherein, the distance between the bag body and the fermentation tank satisfies h2 / h1=0.3~0.75, where h1 is the height of the fermentation tank, h2 is the distance between the bottom of the bag body and the bottom wall of the fermentation tank, and the bag body is located below the surface of the livestock and poultry manure liquid in the fermentation tank.

2. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 1, characterized in that, The preparation method of the composite immobilized microbial agent is as follows: Step 1. Bacillus subtilis, Aspergillus oryzae, Aspergillus niger, yeast, lactic acid bacteria and denitrifying bacteria are cultured in liquid culture separately, and then the fermentation broths of each strain are mixed to obtain a mixed fermentation broth; Step 2. Activate and culture the mixed fermentation broth; Step 3. After the activation culture is completed, the mixture is inoculated into a mixture of corn cob, corn flour and soybean flour for fermentation.

3. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 2, characterized in that, In step 1, when mixing the fermentation broths of each microorganism, the volume ratio of each fermentation broth is as follows: Bacillus subtilis fermentation broth : Aspergillus oryzae fermentation broth : Aspergillus niger fermentation broth : yeast fermentation broth : lactic acid bacteria fermentation broth : denitrifying bacteria fermentation broth = (2.5-3.0) : (2.0-2.5) : (2.0-2.5) : (1.0-1.5) : (0.5-1.0) : (1.0-2.5), wherein the concentration of Bacillus subtilis in the Bacillus subtilis fermentation broth is 10. 8 -10 9 The concentration of Aspergillus oryzae fermentation broth was 10 CFU / mL. 7 -10 8 The concentration of Aspergillus niger fermentation broth was 10 CFU / mL. 7 -10 8 CFU / mL, the concentration of the yeast fermentation broth is 10. 8 -10 9 The concentration of the lactic acid bacteria fermentation broth is 10 CFU / mL. 8 -10 9 The concentration of denitrifying bacteria fermentation broth is 10 CFU / mL. 8 -10 9 CFU / mL.

4. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 2, characterized in that, In step 2, the culture medium used for activation culture is a grain substrate with a total sugar content of 5%-8%; the activation culture temperature is 28-32℃ and the time is 24h.

5. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 2, characterized in that, In step 3, the carbon-to-nitrogen ratio of the mixture is 20:1-35:1; the mass ratio of corn cob, corn flour, and soybean flour is (2-3):(4.8-5.6):(1.4-3.2), wherein the particle size of corn cob, corn flour, and soybean flour is 50-100 mesh; before fermentation, the step of adjusting the moisture content of the mixture to 60%-65% is also included; after fermentation, the inoculum cell load is ≥10. 9 CFU / g mixture.

6. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 1, characterized in that, The mass ratio of the composite immobilized microbial agent to the soil is (1-1.5):(1.5-2).

7. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 1, characterized in that, The suspension assembly includes: A ring beam, which is located on the top surface of the fermentation tank; A suspension rod is fixedly connected to the ring beam; wherein, a plurality of the bags are hung on the suspension rod by suspension ropes.

8. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 1, characterized in that, The oxygenation assembly includes an air duct, an oxygenation pump, and a microporous aeration disc located at the bottom of the fermentation tank. The oxygenation pump is installed on the fermentation tank and is connected to the inner cavity of the fermentation tank through the air duct.

9. The livestock and poultry manure black film fermentation system based on composite microbial community immobilization and micro-aerobic control according to claim 1, characterized in that, The cross-section of the fermentation tank is formed as an inverted isosceles trapezoid, with the included angle of the inverted isosceles trapezoid being 65°~75°; A wall is installed on one side of the top surface of the fermentation tank, and an observation port is provided on the wall; A CO2 exhaust pipe is installed on the wall; The fermentation tank is equipped with a roof, which is located above the ring beam and the wall.

10. A method for fermenting livestock and poultry manure based on immobilized composite microbial communities and microaerobic control, characterized in that, The fermentation of livestock and poultry manure is carried out using the black film fermentation system for livestock and poultry manure as described in claim 1; during the fermentation process, the concentration of dissolved oxygen is 0.2~0.5 mg / L.

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