Micro-aerobic-aerobic coupling fermentation composting reactor and process thereof

Abstract

The invention relates to the technical field of compost treatment, and provides a micro-aerobic-aerobic coupling fermentation compost reactor and a process thereof, and the process comprises the following steps: placing raw materials above an aeration component in a kettle body; starting a pump, supplying gas to the aeration component according to a first aeration strategy, and continuing for a first time period to perform micro-aerobic pretreatment on the raw material to obtain a transition raw material; and starting the pump, supplying gas to the aeration component according to a second aeration strategy, and continuing for a second time period so as to perform aerobic fermentation treatment on the transition raw material, thereby obtaining the required compost product. Through the configuration, a coupling fermentation path with a clear parameter boundary and a time scale is formed, and a reproducible micro-aerobic-aerobic coupling fermentation process is constructed; the technological process is switched from a micro-aerobic environment to an aerobic environment in order, so that the structural succession of the microbial community and the staged guidance of a functional metabolism path are realized.

Description

Technical Field

[0001] This invention relates to the field of composting technology, and in particular to a microaerobic-aerobic coupled fermentation composting reactor and its process. Background Technology

[0002] With the improvement of living standards in my country, the demand for meat, eggs, and milk has increased year by year, directly leading to the continuous expansion of livestock and poultry farming and a rapid increase in the amount of livestock and poultry manure produced. Aerobic composting is an important means of treating and utilizing organic waste. It refers to the biodegradation process in an aerobic environment, through the metabolic action of microorganisms, that decomposes organic waste and transforms it into stable humic substances. However, current traditional aerobic composting processes in most regions suffer from problems such as excessively rapid nitrogen volatilization and carbon mineralization, low utilization efficiency of recalcitrant organic matter, insufficient microbial community diversity, high energy consumption and costs, and inadequate greenhouse gas emissions and odor control.

[0003] For example, patent application number 202010511192.8, "A Micro-intelligent Temperature-Controlled Composting Reactor," and patent authorization announcement number CN102757270B, "A Horizontal Cylindrical Rolling Aerobic Fermentation Equipment with Heat Exchange," mainly focus on the engineering implementation aspects such as reactor structural design, heating / insulation methods, and aeration arrangements. Although the relevant devices are equipped with aeration units, they do not simultaneously disclose the closed-loop control logic and its key parameters (such as oxygen concentration threshold, sampling frequency, and aeration rhythm) formed by oxygen sensors, controllers, and actuators. Therefore, it is difficult to support clear technical evidence that they possess oxygen-driven microbial community regulation. Patent application number 202210978079.X, "Integrated Aerobic Fermentation Equipment and Fermentation Process," although it discloses a staged oxygen supply strategy, its oxygen regulation is always limited to aerobic fermentation conditions. Essentially, it belongs to the optimization of oxygen supply parameters under the framework of aerobic metabolism and has not yet constructed a metabolic environment conversion mechanism of micro-aerobic-aerobic alternation. The patent with authorization announcement number CN103011406B, entitled "Improved device and method for sequencing batch primary sedimentation sludge fermentation coupled with denitrification", proposes process parameters related to "micro-aerobic aeration". However, its treatment object is a sludge / sewage treatment system, the process type is micro-aerobic-anaerobic coupled fermentation, and the reaction medium is mainly liquid phase or high water content system. Its treatment target and material mass transfer characteristics are significantly different from composting and solid organic waste fermentation, and it is difficult to directly compare or apply to the micro-aerobic regulation requirements in the composting process.

[0004] It is evident that existing composting reactors and related processes generally lack a coupled fermentation mode that orderly connects microaerobic to aerobic processes, making it difficult to achieve phased guidance of the composting microbial community and functional metabolic processes. Summary of the Invention

[0005] This invention provides a microaerobic-aerobic coupled fermentation composting reactor and its process, which solves the deficiency of the lack of microaerobic-aerobic coupled organic composting fermentation process in the prior art, and realizes a systematic fermentation composting process with oxygen environment as the driving / guiding and the fermentation process flow switching in stages as the core.

[0006] According to a first aspect of the present invention, a microaerobic-aerobic coupled fermentation composting reactor is provided, comprising a vessel body, a vessel cover, an aeration component, an oxygen content sensor, a pump, an air supply pipeline, and a flow metering element, wherein... The aeration components are located at the bottom of the vessel, the vessel lid is located at the top of the vessel, the oxygen content sensor is located below the vessel lid, and the pump is fluidly connected to the aeration components through the gas delivery pipeline, which is equipped with a flow metering element.

[0007] The microaerobic-aerobic coupled fermentation composting reactor provided by the present invention also includes a controller, which is communicatively connected to an oxygen content sensor and a pump.

[0008] According to a second aspect of the present invention, a microaerobic-aerobic coupled fermentation composting process is also provided, which is carried out using the microaerobic-aerobic coupled fermentation composting reactor according to the first aspect of the present invention, comprising the following steps: Place the raw materials above the aeration components inside the reactor; Start the pump to supply gas to the aeration components using the first aeration strategy and continue for a first duration to pre-treat the raw material with micro-oxygen to obtain a transitional raw material; The pump is started to supply gas to the aeration components using the second aeration strategy and continues for a second duration to perform aerobic fermentation treatment on the transition material to obtain the desired compost.

[0009] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, the first aeration strategy is to supply gas intermittently at a first aeration intensity of 0.24 L / (kg·min) at a preset time interval.

[0010] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, the second aeration strategy is to continuously supply gas at a second aeration intensity of 0.36 L / (kg·min).

[0011] The microaerobic-aerobic coupled fermentation composting process provided by the present invention, after the step of starting the pump, supplying gas to the aeration components with a first aeration strategy, and continuing for a first duration, further includes: The transition materials are turned over.

[0012] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, the step of starting the pump, supplying gas to the aeration components using a second aeration strategy, and continuing for a second duration further includes: The second duration is divided into several sub-stage durations; Between any two adjacent sub-stage durations, the transition material is turned over.

[0013] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, there are three sub-stages with equal durations for each sub-stage.

[0014] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, the step of starting the pump, supplying gas to the aeration components with a first aeration strategy, and continuing for a first duration further includes: Oxygen content data inside the reactor is obtained using an oxygen content sensor. Based on the obtained oxygen content data, the controller actively adjusts the duration of the preset time interval and / or the duration of gas supply.

[0015] According to the microaerobic-aerobic coupled fermentation composting process provided by the present invention, the step of starting the pump, supplying gas to the aeration components with a first aeration strategy, and continuing for a first duration further includes: The oxygen content inside the vessel is maintained between 1% and 5%.

[0016] The microaerobic-aerobic coupled fermentation composting process provided by this invention, by clearly defining the microaerobic pretreatment stage and the aerobic main fermentation stage, forms a coupled fermentation path with clear parameter boundaries and time scales, constructing a reproducible microaerobic-aerobic coupled fermentation process. In the microaerobic pretreatment stage, by stably controlling the oxygen concentration at a low oxygen level, a microaerobic environment dominated by facultative metabolism is constructed, inducing the activation of functional microbial communities adapted to low oxygen conditions. This promotes the initial hydrolysis and structural loosening of complex organic components, providing more readily available substrate conditions for subsequent degradation processes. Simultaneously, this stage creates an adaptive foundation for the subsequent expansion of aerobic microorganisms, facilitating a smooth transition in the fermentation process. In the aerobic main fermentation stage, through continuous and stable oxygen supply, the metabolic activity of aerobic microorganisms is enhanced, accelerating the deep degradation and maturation transformation of organic matter. The entire composting process involves an orderly transition from a microaerobic to an aerobic environment, thereby guiding the succession of microbial community structure and functional metabolic pathways in stages. This is a process environment-driven regulation method, rather than a corrective control method that simply relies on adjusting aeration parameters. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the microaerobic-aerobic coupled fermentation composting reactor provided by the present invention.

[0019] Figure 2 This is a flowchart of the microaerobic-aerobic coupled fermentation composting process provided by the present invention.

[0020] Figure 3 This is a graph showing the effect of different treatments provided by this invention on the degree of decomposition during the composting process.

[0021] Figure 4 This is a graph showing the impact of different treatments provided by this invention on the cumulative emissions of CO2 and NH3 during composting.

[0022] Figure 5 This is a graph showing the effect of different treatments provided by this invention on lignocellulose during composting.

[0023] Figure 6 This is a graph showing the effect of different treatments provided by this invention on the total humus during composting.

[0024] Figure label: 1. Reactor body; 2. Reactor cover; 3. Aeration components; 4. Leachate collection port; 5. Valve; 6. Gas collection port; 7. Temperature sensor; 8. Oxygen content sensor; 9. Controller; 10. Pump; 11. Gas pipeline; 12. Flow metering element; 13. Aeration port. Detailed Implementation

[0025] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0026] In the description of the embodiments of this application, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections, wherein a fixed connection can include an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0028] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0030] The following is combined Figures 1 to 6 This invention describes the microaerobic-aerobic coupled fermentation composting reactor and its process.

[0031] Figure 1 This is a schematic diagram of the microaerobic-aerobic coupled fermentation composting reactor provided by the present invention, as shown below. Figure 1 As shown, the microaerobic-aerobic coupled fermentation composting reactor (hereinafter referred to as the "composting reactor") includes a vessel body 1, a vessel cover 2, an aeration component 3, an oxygen content sensor 8, a pump 10, an air supply pipeline 11, and a flow metering element 12.

[0032] The vessel body 1 is a container with a certain volume, for example, 20L. The vessel body 1 can be designed with an open top. The aeration component 3 can be located at the bottom of the vessel body 1, and the vessel lid 2 covers the top of the vessel body 1. The aeration component 3 can be constructed using a pipe arrangement, with several aeration holes (not shown in the figure) along its length, allowing the aeration component 3 to be placed flat at the bottom of the vessel body 1. The oxygen content sensor 8 is located below the vessel lid 2, for example, fixedly connected to the vessel lid 2 and extending downwards a certain distance from the vessel lid 2. The pump 10 is arranged at any location outside the vessel body 1 and is fluidly connected to the aeration component 3, particularly the aeration port 13, via an air supply line 11. Furthermore, the air supply line 11 is equipped with a flow metering element 12.

[0033] The composting reactor also includes a controller 9, which is communicatively connected to both an oxygen content sensor 8 and a pump 10. In this embodiment, the controller 9 is fixedly connected to the upper surface of the reactor lid 2 and communicates with the oxygen content sensor 8 located below the lid 2 via a cable passing through it, thereby obtaining the oxygen content within the reactor body 1 in real time. Furthermore, the communication connection between the controller 9 and the pump 10 can be wired or wireless, allowing the controller 9 to start / stop the pump 10 or adjust its operating power.

[0034] The operating principle of this composting reactor is as follows: oxygen sensor 8 detects the oxygen concentration inside the vessel 1 in real time and transmits the obtained oxygen concentration data to controller 9; controller 9 dynamically compares the real-time data with a preset threshold and outputs a control command for aeration, such as controlling the start and stop of pump 10 via a relay, thereby realizing real-time adjustment of the aeration process. Oxygen sensor 8, controller 9, and pump 10 form a simple and efficient control chain, enabling the composting reactor to directly serve the process objectives and improving the stability and operational reliability of the entire system.

[0035] With the above configuration, the oxygen content in the reactor 1 can be monitored in real time. Thus, the real-time oxygen concentration is used as the core control variable. A closed-loop control system is constructed by oxygen content sensor 8, controller 9 and pump 10 to realize the real-time adjustment of the aeration state. This transforms the oxygen content in the reactor 1 from a passive result variable to an actively controllable variable, significantly improving the controllability of the composting process.

[0036] Furthermore, the composting reactor also includes a leachate collection port 4, which is located at the bottom of the reactor body 1, at a different location than the aeration port 13. The leachate collection port 4 may be equipped with a valve 5 to open / close the leachate collection port 4, thereby collecting the waste liquid in the reactor body 1 in a timely manner for further treatment.

[0037] Furthermore, the composting reactor also includes a gas collection port 6, which is located on the lid 2 at a different position than the controller 9 / oxygen sensor 8. The gas collection port 6 may also be equipped with a valve 5 to open / close the gas collection port 6, thereby collecting fermentation gases inside the reactor body 1 in a timely manner to reduce the amount of greenhouse gases / polluting gases directly emitted into the ambient atmosphere.

[0038] Furthermore, the composting reactor also includes a temperature sensor 7, which is used to detect the temperature inside the vessel 1 in real time. This allows the operator to estimate the current fermentation level based on the obtained temperature data and adjust the operating power of the pump 10 accordingly. This enables the fermentation process inside the vessel 1 to enter a pre-designed stage / step, with the real-time oxygen concentration as the control variable. In this embodiment, the temperature sensor 7 passes through the lid 2 and extends into the vessel 1, preferably into the raw materials used to prepare organic compost. Moreover, when the temperature sensor 7 passes through the lid 2, it is fixedly connected to the lid 2, for example, by means of adhesives or other bonding methods.

[0039] Figure 2 This is a flowchart of the microaerobic-aerobic coupled fermentation composting process provided by the present invention, as follows: Figure 2 As shown, this microaerobic-aerobic coupled fermentation composting process (hereinafter referred to as the "fermentation composting process") is carried out using the above-mentioned composting reactor and includes the following steps: Step S1: Place the raw material above the aeration component 3 inside the vessel body 1; Step S2: Start pump 10 to supply gas to aeration component 3 with the first aeration strategy and continue for a first duration to perform micro-oxygen pretreatment on the raw material to obtain transition raw material; Step S3: Start pump 10 to supply gas to aeration component 3 using the second aeration strategy and continue for a second duration to perform aerobic fermentation treatment on the transition material to obtain the desired compost.

[0040] For step S1, livestock and poultry manure can be selected as the main raw material for organic compost. For example, pig manure can be used as the main raw material, while straw and vegetable waste can be used as auxiliary raw materials. It is conceivable that in the context of livestock and poultry farming, the above raw materials are usually provided in the form of wet matter containing water. Therefore, in the provided raw materials, pig manure, straw, and vegetable waste are mixed in a wet weight ratio of 65% : 20% : 15%.

[0041] For step S2, in the initial stage of this fermentation composting process, the raw materials undergo microaerobic pretreatment. The start and stop of pump 10 are controlled by controller 9 (and possibly a relay), causing pump 10 to supply gas to aeration component 3 using a first aeration strategy. This creates a microaerobic environment dominated by facultative metabolism within the reactor body 1, inducing the activation of functional microbial communities adapted to low-oxygen conditions. The first duration of the microaerobic pretreatment stage can be set to 3 days.

[0042] For step S3, the operating power of pump 10 is adjusted using controller 9 (and possibly a relay), so that pump 10 supplies gas to aeration component 3 using the second aeration strategy, thereby creating an aerobic environment dominated by aerobic metabolism within the reactor 1 and enhancing the metabolic activity of aerobic microorganisms. The second duration of the aerobic main fermentation stage can be set to 18 days.

[0043] Through the above configuration, the microaerobic pretreatment stage and the aerobic main fermentation stage are clearly defined, forming a coupled fermentation path with clear parameter boundaries and time scales, and constructing a reproducible microaerobic-aerobic coupled fermentation process.

[0044] Furthermore, in the microaerobic pretreatment stage, by stably controlling the oxygen concentration at a low oxygen level, a microaerobic environment dominated by facultative metabolism is constructed. This induces the activation of functional microbial communities adapted to low oxygen conditions, promoting the initial hydrolysis and structural loosening of complex organic components (e.g., macromolecules of lignocellulose), providing more readily available substrate conditions for subsequent degradation processes. Simultaneously, this microaerobic pretreatment stage creates an adaptive foundation for the subsequent expansion of aerobic microorganisms, facilitating a smooth transition in the fermentation process. In the aerobic main fermentation stage, continuous and stable oxygen supply enhances the metabolic activity of aerobic microorganisms, accelerating the deep degradation and maturation of organic matter.

[0045] It is important to note that in the microaerobic pretreatment stage, a microaerobic environment refers to an environment with a certain oxygen content, but the oxygen content has not yet reached aerobic conditions. In a microaerobic environment, the microorganisms used are mainly facultative microorganisms, as well as some aerobic and anaerobic microorganisms. This is significantly different from the well-known anaerobic environment, which refers to an environment that does not contain oxygen; and in an anaerobic environment, the microorganisms used are primarily anaerobic microorganisms.

[0046] Furthermore, the first aeration strategy involves intermittently supplying gas at a first aeration intensity of 0.24 L / (kg·min) at preset time intervals. In the micro-aerobic pretreatment stage corresponding to step S2 above, to construct the aforementioned micro-aerobic environment, the first aeration intensity can be set relatively low, and the aeration process can be intermittent rather than continuous. Therefore, the controller 9 not only controls the start and stop of the pump 10 to achieve intermittent gas supply from the pump 10 to the aeration component 3, but also adjusts the operating power of the pump 10 to be relatively low to reduce the amount of gas supplied by the pump 10 to the aeration component 3 during a specific time window.

[0047] Furthermore, the second aeration strategy involves continuously supplying gas at a second aeration intensity of 0.36 L / (kg·min). In the aerobic primary fermentation stage corresponding to step S3 above, to establish the aforementioned aerobic environment, the second aeration intensity needs to be set relatively high, and the aeration process can be continuous. Therefore, the controller 9 adjusts the operating power of the pump 10 to a relatively high level to increase the amount of gas supplied by the pump 10 to the aeration component 3 during a specific time window.

[0048] It should be noted that the first / second aeration intensities mentioned above mean that the aeration rate is 0.24 / 0.36 L per minute for every 1 kg of dry raw material (as opposed to the aforementioned terms "moist" or "wet").

[0049] This configuration breaks through the conventional design of traditional composting processes that use aeration volume, aeration duration, or turning frequency as the main control parameters. Instead, it uses the real-time oxygen concentration of the raw material / intermediate raw material pile within the reactor 1 as the sole core control variable. The oxygen content sensor 8 detects the oxygen concentration within the reactor 1 in real time and transmits it to the controller 9. The controller 9 outputs a control command for aeration based on the comparison results, controlling the start and stop of the pump 10 (e.g., via a relay). This achieves a closed-loop control system of "oxygen sensing - intelligent decision-making - execution feedback," transforming oxygen concentration from a passive, outcome-based indicator into an actively controllable driving factor / variable.

[0050] Furthermore, the fermentation composting process further includes the following after step S2: Step S21: Perform a turning operation on the transition material.

[0051] For step S21, after the micro-oxygen pretreatment stage corresponding to step S2 above is completed, the transition material obtained from the micro-oxygen pretreatment is poured out of the reactor 1 and subjected to a turning operation, which serves as the physical switch between stages of the entire process. Preferably, during the turning operation, the operator can also take samples from the transition material to detect the relevant parameter performance of the transition material after micro-oxygen pretreatment.

[0052] Furthermore, step S3 in this fermentation composting process also includes: Step S31: Divide the second duration into several sub-stage durations; Step S32: Between any two adjacent sub-stage durations, perform a turning operation on the transition material.

[0053] Since the second stage of aerobic primary fermentation can be set to, for example, 18 days, this duration is relatively long. During this period, if the transition material remains stationary, uneven consumption of organic matter may occur within the transition material pile due to differences in oxygen supply and microbial activity. Therefore, turning the pile is necessary to improve the distribution of materials and oxygen and promote uniform degradation of organic matter.

[0054] Therefore, the second duration is divided into several sub-stage durations. After the previous sub-stage is completed, similar to step S21 above, the material that has undergone the corresponding aerobic main fermentation sub-stage (e.g., the first time) is poured out of the reactor 1 and turned over, which serves as a physical switch between the sub-stages of the aerobic main fermentation stage. Preferably, during the turning operation, the operator can also take samples from the material to detect the relevant parameter performance of the material after the corresponding aerobic main fermentation sub-stage treatment.

[0055] Furthermore, there are three sub-stages, each with a duration of approximately equal length. Thus, the second stage, for example, lasting 18 days, is divided into three equal sub-stages, each lasting 6 days. Moreover, after the first and second sub-stages are completed, the material is turned over to prevent uneven distribution of material and oxygen within the pile, which could reduce fermentation efficiency.

[0056] In addition, the second duration is divided into sub-stages with similar durations, which facilitates the controller 9 in controlling the start and stop of the pump 10, and also makes it easier for operators to manage the turning operation.

[0057] Furthermore, step S2 in the fermentation composting process also includes: Step S22: Obtain oxygen content data inside the vessel 1 using oxygen content sensor 8; Step S23: Adjust the duration of the preset time interval and / or the duration of gas supply based on the obtained oxygen content data.

[0058] During the microaerobic pretreatment stage, it is necessary to maintain a delicate balance in the microaerobic environment in order to sustain the facultative metabolism of facultative microorganisms and some aerobic microorganisms. Excessive or insufficient oxygen supply from the aeration component 3 may cause the fermentation composting process to prematurely transition to the aerobic main fermentation stage, or transform into an anaerobic environment that is not desired by this invention. Therefore, the oxygen content sensor 8 can monitor the oxygen content data within the vessel 1 in real time, allowing operators to assess whether the exact environment within the vessel 1 is anaerobic, microaerobic, or aerobic.

[0059] Furthermore, unlike the aerobic main fermentation stage corresponding to step S3 above, the microaerobic pretreatment stage can adjust the duration of the preset time interval and / or the duration of gas supply based on the real-time oxygen concentration in the vessel 1. For example, when the real-time oxygen concentration is relatively high, the controller 9 can extend the preset time interval of intermittent gas supply, thereby allowing the oxygen in the vessel 1 to be consumed by the microbial community performing facultative metabolism; or, the controller 9 can shorten the duration of intermittent gas supply, and with the first aeration intensity unchanged (maintained at approximately 0.24 L / (kg·min)), the oxygen supply obtained by the vessel 1 is reduced, and vice versa.

[0060] Furthermore, step S2 in the fermentation composting process also includes: The oxygen content inside vessel 1 is maintained between 1% and 5%.

[0061] It is conceivable that maintaining an oxygen content between 1% and 5% is the inherent requirement for a micro-oxygen environment.

[0062] From the perspective of the entire fermentation composting process of this invention, the fermentation process is clearly divided into a microaerobic pretreatment stage and an aerobic main fermentation stage. Clear time scales, oxygen concentration ranges, and operating modes are set for each stage, forming a microaerobic-aerobic coupled fermentation process path with clear boundary conditions and repeatability. This design avoids the randomness of the natural changes in the oxygen environment over time in traditional composting processes, transforming the stage switching in the composting process from an "experience-driven" to a "stage-driven" model.

[0063] In one embodiment, pig manure was selected as the main composting material, and straw and vegetable waste were selected as auxiliary composting materials. The three were mixed in a wet weight ratio of 65% : 20% : 15%. A 20L sealed composting reactor was used to conduct a 3-day microaerobic pretreatment combined with an 18-day aerobic primary fermentation composting experiment (experimental treatments are shown in Table 1). During the microaerobic pretreatment, intermittent aeration was carried out at a first aeration intensity of 0.24 L / (kg min) through intelligent adjustment by an oxygen content sensor 8, a controller 9, and a pump 10. At the same time, experimental groups were set up under different microaerobic environments with oxygen contents of 1%, 2%, 3%, and 5%, respectively, and a control group (ControlCheck, CK) was set up with conventional aerobic treatment (continuous aeration at an aeration intensity of 0.36 L / (kg min)). During the experiment, the CO2 and NH3 gas contents were measured daily through gas collection port 6. At the end of the microaerobic pretreatment stage, the pile is turned over once, and during the aerobic main fermentation stage, the pile is turned over once every 6 days, and material samples are collected during the turning.

[0064] Table 1: Parameters of different fermentation composting processes Figure 3 This is a graph showing the effect of different treatments provided by this invention on the degree of decomposition during the composting process, such as... Figure 3 As shown, the germination index (GI) of the microaerobic-aerobic coupled treatments T1, T2, T3, and T4 were 109%, 107%, 105%, and 109%, respectively, which were not significantly different from the conventional aerobic treatment CK (GI of 108%). This demonstrates that the microaerobic-aerobic coupled treatment can achieve the required germination rate.

[0065] Figure 4 This is a graph showing the impact of different treatments provided by this invention on the cumulative emissions of CO2 and NH3 during composting, such as... Figure 4 As shown, the microaerobic-aerobic coupled treatments T1, T2, T3, and T4 significantly reduced cumulative CO2 emissions by 31.3%, 39.1%, 42.9%, and 39.1% respectively compared to the conventional aerobic treatment CK, and significantly reduced cumulative NH3 emissions by 44.3%, 50.5%, 50.3%, and 49.89% respectively. This demonstrates that the microaerobic-aerobic coupled treatment can significantly reduce cumulative CO2 and NH3 emissions, thereby reducing the emission of greenhouse gases and pollutants into the ambient atmosphere.

[0066] Figure 5 This is a graph showing the effect of different treatments on lignocellulose during composting, as provided by the present invention. Figure 5As shown, at the end of the microaerobic pretreatment stage (day 3), compared with the conventional aerobic treatment (CK), the contents of lower cellulose, hemicellulose, and lignin in T1, T2, T3, and T4 all showed varying degrees of decrease. This indicates that microaerobic pretreatment can promote the degradation of lignocellulose components. Especially at the end of composting, the microaerobic-aerobic coupled treatments T1, T2, T3, and T4 showed a more significant effect on the degradation of recalcitrant lignin, with its content decreasing by 5.46%, 11.90%, 9.01%, and 9.54% respectively compared to CK.

[0067] Figure 6 This is a graph showing the effect of different treatments provided by this invention on the total humus during composting, such as... Figure 6 As shown, at the end of composting, compared with the conventional aerobic treatment CK, the total humic content of the microaerobic-aerobic coupled treatments T1, T2, T3, and T4 increased by 9.81%, 13.6%, 10.4%, and 7.76%, respectively. This indicates that the microaerobic-aerobic coupled treatment can promote humic formation in compost products.

[0068] Moreover, since the microaerobic pretreatment stage in the early stage of this fermentation composting process adopts an intermittent aeration method with low aeration intensity, the microaerobic-aerobic coupled treatment can achieve energy savings of 6.67% to 12.2% while ensuring the treatment effect.

[0069] In summary, the microaerobic-aerobic coupled fermentation composting reactor and its process provided by this invention, using pig manure as the main material and straw and vegetable waste as auxiliary materials for composting, achieves synergistic optimization of pollutant emission reduction, efficient organic matter conversion, and energy saving while ensuring the quality of compost maturation. Among them, the microaerobic-aerobic coupled treatment with a microaerobic content of 2% exhibits the best overall performance in various technical indicators.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microaerobic-aerobic coupled fermentation composting reactor, characterized in that, It includes the vessel body, vessel cover, aeration components, oxygen content sensor, pump, gas delivery pipeline, and flow metering element, among which... The aeration component is located at the bottom of the vessel body, the vessel cover is located at the top of the vessel body, the oxygen content sensor is located below the vessel cover, the pump is fluidly connected to the aeration component through the gas supply pipeline, and the gas supply pipeline is equipped with the flow metering element.

2. The microaerobic-aerobic coupled fermentation composting reactor according to claim 1, characterized in that, It also includes a controller, which is communicatively connected to both the oxygen content sensor and the pump.

3. A microaerobic-aerobic coupled fermentation composting process, which is implemented using a microaerobic-aerobic coupled fermentation composting reactor according to any one of claims 1 to 2, characterized in that, Includes the following steps: Place the raw materials above the aeration components inside the reactor; The pump is started to supply gas to the aeration component using the first aeration strategy and continue for a first duration to perform micro-oxygen pretreatment on the raw material to obtain a transitional raw material. The pump is started to supply gas to the aeration components using the second aeration strategy and continues for a second duration to perform aerobic fermentation treatment on the transition material to obtain the desired compost.

4. The microaerobic-aerobic coupled fermentation composting process according to claim 3, characterized in that, The first aeration strategy is to supply gas intermittently at a first aeration intensity of 0.24 L / (kg·min) at preset time intervals.

5. The microaerobic-aerobic coupled fermentation composting process according to claim 3, characterized in that, The second aeration strategy is to continuously supply gas at a second aeration intensity of 0.36 L / (kg·min).

6. The microaerobic-aerobic coupled fermentation composting process according to claim 3, characterized in that, The step of starting the pump, supplying gas to the aeration component according to the first aeration strategy, and continuing for a first duration, further includes: The transition material is turned over.

7. The microaerobic-aerobic coupled fermentation composting process according to claim 3, characterized in that, The step of starting the pump, supplying gas to the aeration component using the second aeration strategy, and continuing for the second duration further includes: The second duration is divided into several sub-stage durations; Between any two adjacent sub-stage durations, the transition material is turned over.

8. The microaerobic-aerobic coupled fermentation composting process according to claim 7, characterized in that, The number of sub-stage durations is three, and the durations of each sub-stage are equivalent to each other.

9. The microaerobic-aerobic coupled fermentation composting process according to claim 3 or 4, characterized in that, The step of starting the pump, supplying gas to the aeration component according to the first aeration strategy, and continuing for a first duration further includes: Oxygen content data inside the vessel is obtained using an oxygen content sensor; Based on the obtained oxygen content data, the controller actively adjusts the duration of the preset time interval and / or the duration of gas supply.

10. The microaerobic-aerobic coupled fermentation composting process according to claim 9, characterized in that, The step of starting the pump, supplying gas to the aeration component according to the first aeration strategy, and continuing for a first duration further includes: The oxygen content inside the vessel is maintained between 1% and 5%.

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