Livestock manure composting fermentation process optimization control method

Abstract

The application discloses a livestock and poultry manure compost fermentation process optimization control method and relates to the technical field of compost fermentation. First, the dynamic baseline median and tolerance are constructed, and the carbon and nitrogen metabolism tension index (pH jump degradation) is calculated, so that the precursor of metabolic imbalance is identified before the ammonia concentration sharply rises; when the index exceeds the dynamic threshold, the ventilation interval and air volume are dynamically adjusted according to the core temperature and tail gas oxygen concentration to avoid insufficient oxygen supply or excessive cooling; at the same time, the carbon supplement amount is accurately determined based on the residual organic carbon estimate value and the carbon consumption ratio, and whether the carbon supplement is effective, insufficient or excessive is judged through the tail gas ammonia concentration feedback, and then the ventilation, additional carbon supplement or ventilation interval are adjusted; finally, the whole layer is turned over by the condition that the temperature change rate changes from positive to negative and the change acceleration is continuously negative, so that the carbon source and the bacterial population are uniformly distributed again. The application can control the ammonia concentration in the composting process within a fluctuation range, thereby effectively preventing the generation of mutation peaks.

Description

Technical Field

[0001] This invention relates to the field of composting fermentation technology, specifically to an optimized control method for livestock and poultry manure composting fermentation process. Background Technology

[0002] In the composting and fermentation process of livestock and poultry manure, the abrupt inflection point of ammonia release is not triggered by a single parameter, but rather is a nonlinear emergent result of the coupling effect of multiple parameters. When fermentation enters the stage of carbon and nitrogen metabolism stress, the changes in various parameters often precede the sharp rise in ammonia concentration. However, due to the lack of effective multi-parameter fusion judgment methods, existing technologies have the following shortcomings: First, existing methods usually rely on fixed thresholds for single parameters to judge fermentation anomalies, making it difficult to predict the timing of ammonia release inflection points before they occur, resulting in detection lag. Second, existing technologies lack standardized intervention actions and linkage mechanisms with real-time status of multiple parameters. Operations such as ventilation, carbon replenishment, and turning are usually performed according to fixed schedules or manual experience, failing to make precise adjustments based on the current carbon and nitrogen metabolism stress of the compost pile, resulting in poor intervention effects and repeated ammonia concentration abrupt peaks.

[0003] Therefore, there is a need for an optimized control method for the composting and fermentation process of livestock and poultry manure. This method involves constructing a multi-parameter dynamic baseline and calculating the carbon and nitrogen metabolism stress index. Once the stress index exceeds a threshold, ventilation, carbon replenishment, and turning of the compost can be adjusted in a coordinated manner. This ensures that the ammonia concentration does not experience a sudden peak when the ammonia release inflection point cannot be predicted. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an optimized control method for livestock and poultry manure composting and fermentation processes. This method solves the problem of how to prevent ammonia concentration from experiencing abrupt peaks during composting when the inflection point of ammonia release cannot be predicted. This is achieved by integrating multi-parameter judgment and standardized intervention actions.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a method for optimizing and controlling the composting and fermentation process of livestock and poultry manure, comprising the following steps: constructing the baseline median and baseline tolerance of the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend of the compost core, and updating the baseline median and baseline tolerance when the temperature difference between the compost core temperature and the ambient temperature is greater than the temperature threshold and the duration is greater than the preset duration.

[0006] When the pH value in the reactor does not change abruptly, the carbon and nitrogen metabolism stress index is determined based on the offset of the baseline median and the baseline tolerance, combined with the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend. Otherwise, the pH change trend is excluded when calculating the degraded carbon and nitrogen metabolism stress index.

[0007] Once the carbon and nitrogen metabolism stress index is determined to be downgraded or exceeds the dynamic threshold, the ventilation interval and air volume are determined based on the core temperature and exhaust gas oxygen concentration.

[0008] When ventilating based on ventilation intervals and air volume, determine the estimated value of residual organic carbon, and determine the amount of carbon supplementation by combining the carbon and nitrogen metabolism stress index or the downgraded carbon and nitrogen metabolism stress index and the CO2 release rate. At the same time, determine whether to maintain ventilation, add additional carbon, or determine excessive carbon supplementation and adjust the ventilation interval based on the ammonia concentration in the exhaust gas.

[0009] After carbon replenishment is completed, full-layer turning is performed based on temperature change rate.

[0010] Compared to existing technologies, this invention offers the following advantages: First, it establishes dynamic baseline medians and tolerances for the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trends within the compost core. It also calculates the carbon and nitrogen metabolic stress index (degradation during pH jumps), thus identifying precursors to metabolic imbalance before ammonia concentration rises sharply. When the index exceeds a dynamic threshold, the ventilation interval and airflow are dynamically adjusted based on the core temperature and exhaust gas oxygen concentration to prevent insufficient oxygen supply or excessive cooling. Simultaneously, the amount of carbon supplementation is precisely determined based on the estimated remaining organic carbon and carbon consumption ratio. Feedback from the exhaust gas ammonia concentration indicates whether the supplementation is effective, insufficient, or excessive, allowing for continued ventilation, additional carbon supplementation, or adjustment of the ventilation interval. Finally, a full-layer turning is triggered when the temperature change rate turns from positive to negative and the acceleration of change is continuously negative, resulting in a more uniform redistribution of carbon sources and microbial communities. The synergistic effect of these multi-parameter fusion judgments and standardized interventions ensures that ammonia concentration remains within a fluctuating range during composting, effectively preventing sudden peaks. Attached Figure Description

[0011] Figure 1 This is a flowchart of the optimized control method for livestock and poultry manure composting and fermentation process of the present invention;

[0012] Figure 2 This is a flowchart illustrating the construction of baseline median and baseline tolerance in the optimized control method for livestock and poultry manure composting and fermentation process of the present invention;

[0013] Figure 3 This is a flowchart for determining the estimated value of residual organic carbon in the optimized control method for livestock and poultry manure composting and fermentation process of the present invention.

[0014] Figure 4 The curves showing the change of NH3 concentration over time under the fixed carbon supplementation and dynamic carbon supplementation strategies in the optimized control method for livestock and poultry manure composting fermentation process of the present invention are shown. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Please refer to the accompanying drawings. Figure 1The present invention provides a technical solution: a method for optimizing and controlling the composting and fermentation process of livestock and poultry manure, comprising the following steps: S1, constructing the baseline median and baseline tolerance of the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend of the core, and updating the baseline median and baseline tolerance when the temperature difference between the core temperature and the ambient temperature is greater than the temperature threshold (e.g., 5°C) and the duration is greater than the preset duration.

[0016] During composting fermentation, significant differences exist in material characteristics, environmental conditions, and microbial activity between different batches. This results in fluctuations in core temperature, tail gas ammonia concentration, CO2 release rate, and pH within the compost pile, which are not constant. Using pre-set fixed thresholds to identify anomalies can easily lead to misjudgments due to batch-to-batch variations. Therefore, a method is needed that can adaptively learn the parameter distribution of each fermentation batch's initial stable phase to establish a batch-specific dynamic reference baseline. Furthermore, as fermentation progresses, the compost pile state evolves slowly, and the original baseline may no longer reflect the current health benchmark. Therefore, it is also necessary to proactively trigger baseline updates when a clear indicator of metabolic activity—such as a prolonged period of high temperature (core temperature consistently exceeding ambient temperature)—is observed. This ensures the reference standard remains aligned with the current fermentation stage, preventing misjudgments of normal fluctuations in later stages based on early baselines.

[0017] Based on the above factors, such as Figure 2 As shown, the process of constructing the baseline median and baseline tolerance is as follows: S101, In the initial stage after the start of compost fermentation, the core temperature, tail gas ammonia concentration, CO2 release rate, and pH value within the compost pile are continuously collected at a fixed sampling period (e.g., data is recorded every 10 minutes). The entire collection process does not stop immediately but continues until the termination point defined in S103 is triggered.

[0018] S102. Calculate the temperature change rate, ammonia concentration gradient, and pH trend at each sampling time based on the collected time-series data. The temperature change rate is expressed in degrees Celsius per hour, the ammonia concentration gradient in milligrams per cubic meter per hour, and the pH trend is a unitless hourly slope.

[0019] S103. The moment when the core temperature first reaches the set temperature is taken as the end point of the initial stage. If the core temperature never reaches the set temperature, the preset time after startup is taken as the end point. For example, the set temperature is 50°C. The preset time is set according to the composting process type, for example, 72 hours for windrow composting, 48 hours for trench composting, or 24 hours for reactor composting.

[0020] S104. Sort the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend in the initial stage from smallest to largest, calculate their medians and interquartile ranges, take their medians as the baseline median of the corresponding parameters, and take their interquartile ranges as the baseline tolerance of the corresponding parameters.

[0021] During the composting fermentation process, ambient temperature is continuously collected, and the duration for which the core temperature exceeds the ambient temperature is recorded. When the duration exceeds a preset time, a baseline update is triggered. After triggering, the core temperature, exhaust ammonia concentration, exhaust CO2 concentration, ventilation flow rate, and pH value within the compost pile are collected within a complete update window starting from the current trigger time (the duration of the complete update window is equal to the duration of the initial stage). Based on the collected time-series data, the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend at each sampling time are calculated. The median and interquartile range of the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend are calculated respectively. The calculated median replaces the current baseline median of the corresponding parameter, and the calculated interquartile range replaces the current baseline tolerance of the corresponding parameter. The recorded duration is then cleared to zero.

[0022] The core temperature, measured in degrees Celsius, represents the temperature in the central region of the compost material. It is acquired in real-time by a temperature sensor inserted into the center of the compost pile. The value reflects the intensity of heat production from microbial metabolism.

[0023] Ammonia concentration in the exhaust gas indicates the ammonia content in the compost exhaust gas, measured in milligrams per cubic meter. It is continuously collected by an ammonia sensor (such as an electrochemical sensor or laser gas analyzer) installed on the exhaust pipe or at the exhaust port of the covering membrane. The numerical value reflects the intensity of hydrolysis and ammonification of nitrogen-containing organic matter.

[0024] The pH value within the compost pile indicates the acidity or alkalinity of the compost material. It is continuously collected by a pH electrode sensor inserted into the pile. The value reflects the acidity or alkalinity of the fermentation environment.

[0025] Temperature change rate represents the rate at which the reactor core temperature changes over time. It is calculated by dividing the difference in core temperature between adjacent sampling times by the sampling period. A positive value indicates a temperature rise in the reactor core (heat generation exceeds heat dissipation), while a negative value indicates a temperature drop; the larger the absolute value, the more drastic the temperature change.

[0026] The ammonia concentration gradient represents the rate of change of ammonia concentration in the exhaust gas over time. It is calculated by dividing the difference in ammonia concentration at adjacent sampling times by the sampling period. A positive value indicates accelerated ammonia release, suggesting faster hydrolysis of nitrogen-containing organic matter or increased pH promoting ammonia volatilization; a negative value indicates slower ammonia release. The larger the absolute value of the gradient, the more drastic the change in the nitrogen loss rate.

[0027] The pH trend represents the slope of pH change within the pile over time. It is calculated by performing a least-squares linear fit using multiple pH values ​​collected within the current time window, and the slope of the fitted line is used as the pH trend. The time window length is consistent with the calculation window for the carbon and nitrogen metabolic stress index. Positive values ​​indicate an increase in pH, negative values ​​indicate a decrease in pH, and larger absolute values ​​indicate a faster rate of pH change.

[0028] The CO2 release rate is calculated by dividing the exhaust CO2 concentration (volume percentage) by 100, multiplying by the current ventilation flow rate (cubic meters per hour), and then multiplying by the density of carbon dioxide at standard atmospheric pressure (1.977 kg per cubic meter) to obtain the CO2 release rate in kilograms per hour.

[0029] Ambient temperature refers to the air temperature in the composting workshop or open area, measured in degrees Celsius. It is obtained through air temperature sensors placed near the compost pile and unaffected by the pile's heat radiation. This temperature is compared with the core temperature to determine whether the compost pile has entered an autothermal fermentation state.

[0030] The set temperature is a pre-defined temperature threshold, measured in degrees Celsius, used to define the end of the initial phase.

[0031] The preset duration is a time threshold in hours. It is used to determine whether the reactor body has been in a high-temperature, self-heating state for an extended period, thus triggering a baseline update.

[0032] The initial stage duration refers to the total time, expressed in hours, from fermentation start-up to the initial stage termination point. Its value is not a fixed constant but depends on the moment the core temperature first reaches the set temperature or the preset maximum duration after start-up. This determines the length of the sample data window used to calculate the baseline median and baseline tolerance. The window must contain a sufficient number of sampling periods to stabilize the statistical median and interquartile range.

[0033] The sampling period refers to a fixed time interval for continuously collecting various parameters, measured in minutes or hours. It is set as needed. A shorter sampling period results in higher data resolution, but also increases data volume and storage costs.

[0034] This embodiment introduces a baseline median and baseline tolerance based on the median and interquartile range, providing an adaptive, non-parametric, dynamic reference framework for subsequent assessment of the carbon and nitrogen metabolic stress index. Compared to fixed thresholds, this method, based on the statistical distribution of the current batch at the initial stage, can automatically eliminate batch-to-batch differences in absolute parameter values ​​under different raw materials, auxiliary material ratios, and environmental conditions, thereby improving the robustness and accuracy of subsequent anomaly detection. Simultaneously, using the duration for which the core temperature exceeds the ambient temperature for more than a preset time as the trigger for baseline updates ensures timely baseline refresh after the reactor enters a sustained high-temperature self-heating phase. This avoids false triggers caused by natural parameter drift due to the fermentation process, ensuring that the reference baseline always reflects the normal fluctuation range of the current stage, enabling the entire control method to operate stably for a long period without manual recalibration.

[0035] S2. When the pH value in the pile does not change abruptly, the carbon and nitrogen metabolism stress index is determined based on the offset of the baseline median and the baseline tolerance, combined with the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend. Otherwise, the pH change trend is discarded and the degraded carbon and nitrogen metabolism stress index is calculated.

[0036] During composting, the amplitude and direction of changes in various physicochemical parameters collectively reflect the coordination of microbial carbon and nitrogen metabolism. However, a single parameter deviation from the baseline cannot reliably determine whether metabolism is under stress. Therefore, a multi-parameter fusion quantitative index is needed to comprehensively assess the degree of metabolic stress. Meanwhile, pH sensors are easily affected by material adhesion and liquid seepage in actual composting environments, generating transient jump noise. This jump does not represent the true pH trend, and including it in calculations will severely distort the stress index. To address this, a jump detection mechanism is introduced. When a pH jump occurs, this unreliable parameter is actively removed, and a degradation index is used to maintain assessment accuracy, avoiding misjudgments or control failures caused by sensor noise.

[0037] S201. The condition for determining that the pH value in the pile has not changed is as follows: During the composting fermentation process, the pH value in the pile is continuously collected. The pH value in the pile at the current sampling time is subtracted from the pH value in the pile at the previous sampling time to obtain the pH value change. If the absolute value of the pH value change is greater than the preset change threshold, it is determined that the pH value in the pile has changed; otherwise, it is determined that no change has occurred.

[0038] S202. The process of determining the carbon and nitrogen metabolic stress index is as follows: calculate the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend at the current moment.

[0039] The corresponding current baseline median was subtracted from the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend to obtain four offsets.

[0040] Divide each offset by its corresponding current baseline tolerance to obtain four offset intensities. Sum the squares of the four offset intensities and then take the square root to obtain the carbon and nitrogen metabolic stress index.

[0041] S203. The process of calculating the downgraded carbon and nitrogen metabolic stress index is as follows: remove the pH change trend, and subtract the corresponding current baseline median from the temperature change rate, ammonia concentration gradient and CO2 release rate to obtain three offsets.

[0042] Divide each offset by its corresponding current baseline tolerance to obtain three offset intensities. Sum the squares of the three offset intensities and then take the square root to obtain the degraded carbon and nitrogen metabolic stress index.

[0043] The preset jump threshold is a pre-set positive number with no unit, used to determine whether the change in pH value belongs to jump noise, for example, it is set to 0.5.

[0044] The current baseline median is the median calculated from historical stable phases (such as the initial phase or the most recently updated window) for each of the following parameters: temperature variability, ammonia concentration gradient, CO2 release rate, and pH change trend. It serves as the benchmark value for this parameter under normal conditions. It represents the typical level of this parameter during healthy fermentation; the units differ for different parameters.

[0045] The current baseline tolerance is relative to each of the four parameters mentioned above, representing the interquartile range of the corresponding historical stable phase, and indicating the expected width of normal fluctuations. A larger tolerance indicates that the parameter itself fluctuates more strongly during normal periods, and subsequent offsets can be normalized by dividing by the tolerance.

[0046] Offset refers to the difference between the current value of a parameter and the median value of the current baseline corresponding to that parameter, with the unit being the same as the subtracted parameter. A positive value indicates that the current value is higher than the normal baseline, and a negative value indicates that it is lower than the normal baseline. The larger the absolute value, the more severe the deviation.

[0047] Offset strength equals the offset amount divided by the corresponding current baseline tolerance, and is dimensionless. It represents the degree to which the current parameter deviates from the normal baseline relative to the normal fluctuation width. For example, an offset strength of 1.5 means that the deviation is 1.5 times the normal fluctuation width.

[0048] The carbon and nitrogen metabolic stress index is derived by taking the square root of the sum of the squares of four offset intensities: temperature variability, ammonia concentration gradient, CO2 release rate, and pH change trend. It is dimensionless. A higher value indicates a higher overall stress level in carbon and nitrogen metabolism; an index close to 0 indicates that each parameter is close to its baseline median, suggesting stable metabolism.

[0049] The downgraded carbon and nitrogen metabolic stress index is derived by removing pH trends and taking the square root of the sum of the squares of the three offset intensities: temperature variability, ammonia concentration gradient, and CO2 release rate. It is dimensionless. Similar to the carbon and nitrogen metabolic stress index, it can be used as a backup indicator to continue assessing metabolic status when the pH sensor changes abruptly.

[0050] This embodiment calculates a unitless carbon and nitrogen metabolic stress index by squaring and taking the square root of the deviations of temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend relative to their dynamic baseline median. This index reflects the combined degree of deviation from normal states across multiple metabolic dimensions, solving the problem of high false alarm rates for single-parameter thresholds. Furthermore, by pre-determining whether pH values ​​within the reactor core will jump, and calculating a degraded carbon and nitrogen metabolic stress index after removing the pH change trend when a jump occurs, it ensures that even if the pH sensor is affected by noise, the metabolic state can still be assessed based on the remaining three reliable parameters. This avoids interruptions in the entire control method or the output of erroneous indicators due to momentary sensor anomalies, improving the robustness and field adaptability of the process optimization control method.

[0051] S3. When the carbon and nitrogen metabolism stress index is determined to be downgraded or exceeds the dynamic threshold, the ventilation interval and air volume are determined based on the core temperature and tail gas oxygen concentration.

[0052] When the carbon and nitrogen metabolic stress index exceeds the dynamic threshold, it indicates that microbial metabolism is under abnormal high pressure. At this point, pulsed ventilation is needed to regulate oxygen supply within the reactor core, but the ventilation parameters cannot be fixed. This is because the reactor core's oxygen consumption rate and demand patterns differ at different temperature stages: during warming periods, microbial heat production is vigorous, requiring more frequent ventilation to supply oxygen and dissipate heat; during cooling periods, metabolism slows down, and excessive ventilation can remove too much heat, leading to excessively low temperatures. Simultaneously, the exhaust gas oxygen concentration directly reflects the reactor core's oxygen utilization efficiency: high oxygen concentration indicates excessive ventilation or insufficient microbial oxygen consumption, while low oxygen concentration indicates insufficient oxygen supply. Therefore, it is necessary to dynamically adjust the ventilation interval based on the core temperature change trend and dynamically adjust the single-pass ventilation volume based on the deviation direction of the exhaust gas oxygen concentration, so that the ventilation action can adaptively match the actual oxygen demand and heat dissipation of the current metabolic state.

[0053] Specifically, the process of determining the ventilation interval and airflow based on core temperature and exhaust gas oxygen concentration is as follows: S301, continuously collect the current core temperature and exhaust gas oxygen concentration. The unit of core temperature is degrees Celsius, and the unit of exhaust gas oxygen concentration is volume percentage. Within the most recent complete time window, record multiple sampling points of core temperature change over time. Calculate the difference between the maximum and minimum core temperature values ​​within the time window, and then divide the difference by the duration of the time window to obtain the average rate of change of core temperature, in degrees Celsius per hour.

[0054] S302. The ventilation interval of pulse ventilation is dynamically adjusted based on the sign and magnitude of the average rate of change of core temperature: When the average rate of change is positive, the average duration (from the start point to the end point) of the three most recent continuous increases in core temperature (i.e., the temperature values ​​at adjacent sampling points continuously increase) in historical data is used as the ventilation interval. When the average rate of change is negative, the average duration of the three most recent continuous decreases in core temperature in historical data is used as the ventilation interval. When the average rate of change is zero, the previous ventilation interval remains unchanged.

[0055] S303. Simultaneously, based on the deviation between the current exhaust gas oxygen concentration and the average exhaust gas oxygen concentration within a past complete time window, the single-time air volume of the pulse ventilation is dynamically adjusted: the difference between the current exhaust gas oxygen concentration and the average exhaust gas oxygen concentration within a past complete time window is calculated, and the unit of the difference is volume percentage.

[0056] S304. When the difference is positive, the airflow is set to the average airflow during the period of decreasing exhaust gas oxygen concentration in the past complete time window, multiplied by the ratio of the current exhaust gas oxygen concentration to the minimum exhaust gas oxygen concentration in the past complete time window. When the difference is negative, the airflow is set to the average airflow during the period of increasing exhaust gas oxygen concentration in the past complete time window, multiplied by the ratio of the maximum exhaust gas oxygen concentration in the past complete time window to the current exhaust gas oxygen concentration. When the difference is zero, the previous airflow remains unchanged.

[0057] The oxygen concentration in the exhaust gas represents the volume percentage concentration of oxygen in the composting exhaust gas. It is continuously collected by an oxygen sensor (such as a zirconium oxide or electrochemical sensor) installed on the exhaust pipe or the exhaust port of the covering membrane.

[0058] A complete time window is a fixed duration, set as the product of the sampling period and the preset number of sampling points. It is used to extract a continuous segment of sampling data to calculate statistics such as the average rate of change and the average oxygen concentration. For example, the preset number of sampling points is 24 for windrow composting, 18 for trough composting, and 12 for reactor composting. If no compost type is specified, the default complete time window is 4 hours.

[0059] The ventilation interval, measured in hours, represents the waiting time between two pulse ventilation actions. It is dynamically adjusted by the system and output to the ventilation actuator. A shorter interval results in more frequent ventilation, more abundant oxygen supply, but also faster heat dissipation.

[0060] The duration of the three most recent continuous core temperature rise processes in historical data is in hours, reflecting the typical duration for which the reactor body can maintain a rising trend during the natural heating phase. When used as a ventilation interval, it can synchronize the ventilation rhythm with the heating cycle.

[0061] The duration of the three most recent consecutive core temperature decreases in historical data is in hours, reflecting the typical duration of cooling during the cooling phase of the reactor core. This can be used as a ventilation interval to coordinate ventilation with the cooling rhythm and avoid excessive interference.

[0062] The average oxygen concentration in the exhaust gas over a complete time window represents the baseline level of the recent oxygen concentration in the exhaust gas, and is used to compare with the current value to determine the direction of deviation.

[0063] A positive difference between the current exhaust oxygen concentration and the average value indicates that the current oxygen concentration is higher than the recent average, suggesting reduced oxygen consumption or relatively excessive ventilation; a negative difference indicates that the current oxygen concentration is lower than the recent average, suggesting increased oxygen consumption or insufficient ventilation.

[0064] The average airflow during the period of decreasing oxygen concentration in the exhaust gas within a complete time window is calculated by identifying all periods of continuous decrease in oxygen concentration in the exhaust gas within that time window, and averaging the single airflow for each ventilation during these periods, in cubic meters per ventilation. This reflects the typical airflow level used by the system when the oxygen concentration naturally decreases (increased oxygen consumption by microorganisms).

[0065] The minimum oxygen concentration in exhaust gas within a complete time window represents the lower limit of oxygen concentration when oxygen consumption is most efficient in the recent period.

[0066] The average airflow during the rising phase of exhaust gas oxygen concentration within a complete time window is calculated by identifying all periods of continuous rise in exhaust gas oxygen concentration within the time window, and averaging the single airflow for each ventilation cycle corresponding to these periods, expressed in cubic meters per cycle. This reflects the typical airflow used by the system when oxygen concentration rises (due to excessive ventilation or reduced oxygen consumption).

[0067] The maximum oxygen concentration in exhaust gas within a complete time window represents the upper limit of oxygen concentration that can be achieved after recent ventilation.

[0068] The previous air volume refers to the single air volume value used in the previous pulse ventilation, in cubic meters per pulse.

[0069] This embodiment decomposes ventilation control into two independently adjustable dimensions: ventilation interval and single-pass air volume. These are dynamically adjusted based on the average rate of change of core temperature and the deviation of exhaust gas oxygen concentration, respectively. This ensures that pulse ventilation avoids both excessively short intervals leading to frequent start-stop cycles and wasted energy or excessive cooling, and excessively long intervals causing oxygen deficiency. Simultaneously, the single-pass air volume can automatically increase or decrease based on oxygen utilization efficiency, preventing excessive air volume from dissipating heat and moisture, or insufficient air volume from causing insufficient oxygen supply. This dual-parameter adaptive adjustment method can quickly and accurately restore the oxygen concentration inside the reactor to a suitable range even when carbon and nitrogen metabolism is already strained, while minimizing interference with core temperature stability, thereby effectively suppressing abrupt peaks in ammonia release.

[0070] S4. When ventilating based on ventilation intervals and air volume, determine the estimated value of residual organic carbon, and determine the amount of carbon supplementation by combining the carbon and nitrogen metabolism stress index or the downgraded carbon and nitrogen metabolism stress index and the CO2 release rate. At the same time, determine whether to maintain ventilation, add carbon supplementation, or determine excessive carbon supplementation and adjust the ventilation interval based on the ammonia concentration in the exhaust gas.

[0071] During composting, the rate and total amount of organic carbon decomposed by microorganisms directly affect the carbon-nitrogen metabolic balance, and the amount of remaining organic carbon determines whether an external carbon source needs to be added. However, it is impossible to determine how much usable organic carbon remains in the compost pile through direct weighing or visual observation, because the compost pile is a heterogeneous, dynamically changing, and complex system. Furthermore, one of the main end products of microbial metabolism of organic carbon is carbon dioxide, and the amount of CO2 released in the exhaust gas objectively reflects the degree to which organic carbon has been mineralized and consumed. Therefore, by calculating the initial total organic carbon mass beforehand and then subtracting the total amount of mineralized carbon calculated based on the cumulative CO2 release in the exhaust gas, the current remaining organic carbon mass in the compost pile can be estimated. This indirect estimation method avoids the difficulties of direct measurement, does not rely on manual sampling and testing, and can be performed continuously online.

[0072] like Figure 3 As shown, the process for determining the estimated value of residual organic carbon is as follows: S401. Before the start of composting fermentation, the total dry matter mass of the mixture is calculated based on the mixing ratio of the livestock and poultry manure and auxiliary materials and their respective dry matter mass. Then, the total organic carbon mass is obtained by multiplying the mass fraction of organic carbon in each raw material by the corresponding dry matter mass and summing the results. The unit of total organic carbon mass is kilograms.

[0073] S402. During the composting fermentation process, the CO2 concentration and ventilation flow rate of the exhaust gas are continuously collected. The CO2 concentration is expressed as a volume percentage, and the ventilation flow rate is expressed as cubic meters per hour. The CO2 concentration is divided by 100 and then multiplied by the ventilation flow rate to obtain the CO2 volumetric flow rate. The result is then integrated over time to obtain the cumulative CO2 release from the start of fermentation to the current moment. The cumulative CO2 release is expressed as kilograms.

[0074] S403. Multiply the cumulative CO2 release by the density of carbon dioxide under standard atmospheric pressure to obtain the cumulative CO2 mass. Then multiply by the mass conversion constant between carbon and carbon dioxide. The mass conversion constant is equal to the molar mass of carbon divided by the molar mass of carbon dioxide to obtain the total amount of mineralized carbon consumed.

[0075] S404. Subtract the total amount of mineralized carbon from the total organic carbon mass to obtain the estimated value of the remaining organic carbon at the current moment.

[0076] Livestock and poultry manure refers to the mixture of animal excrement and urine produced during the breeding process, and is the main raw material for composting. Its dry matter mass is obtained by sampling, drying, and weighing. The organic carbon mass fraction in the dry matter is obtained through laboratory elemental analysis or by referring to tables based on empirical values.

[0077] The cumulative CO2 release represents the total volume of carbon dioxide released from the start of fermentation to the present moment, or the concentration integral value converted from the total volume, indicating the mass of carbon dioxide released per cubic meter of the pile. It is obtained by integrating the product of the exhaust gas CO2 concentration and the ventilation flow rate over time and then dividing by the pile volume. It reflects the total amount of mineralized organic carbon; a higher value indicates more organic carbon decomposition and less remaining organic carbon.

[0078] Additives refer to materials added to adjust the carbon-nitrogen ratio, moisture content, and porosity of compost, such as straw, rice husks, and sawdust. Their dry matter mass and organic carbon mass fraction are obtained in the same way as those for livestock and poultry manure.

[0079] The mixing ratio refers to the mass ratio of livestock and poultry manure to auxiliary materials when they are mixed (usually measured by wet or dry weight), which is determined based on the actual amount of materials added.

[0080] Dry matter mass refers to the mass of the solid portion of a material after removing moisture, measured in kilograms. It is obtained by weighing the wet material and multiplying it by the dry matter content (determined by the drying method). The value determines the total solids content of the compost, directly affecting the baseline of the total organic carbon mass.

[0081] Organic carbon mass fraction refers to the proportion of organic carbon in dry matter, and has no unit. It is determined in the laboratory by potassium dichromate oxidation method or elemental analysis. The value varies depending on the type of material: livestock and poultry manure is usually 30%-40%, while straw is about 40%-50%. The higher the value, the more carbon it provides per unit of dry matter.

[0082] Total organic carbon (TOC) refers to the total mass of all organic carbon in the mixture, measured in kilograms. It is obtained by multiplying the dry matter mass of each raw material by its organic carbon mass fraction and then summing the results. It reflects the total carbon pool capacity available to microorganisms at the start of composting and generally ranges from tens to hundreds of kilograms, depending on the size of the compost pile.

[0083] Ventilation flow rate is the volume of air introduced into the reactor structure per unit time, measured in cubic meters per hour. It is continuously collected by a gas flow meter installed on the ventilation duct. A higher flow rate results in a greater amount of CO2 being carried out.

[0084] The mass conversion constant between carbon and carbon dioxide is equal to the molar mass of carbon (12 grams per mole) divided by the molar mass of carbon dioxide (44 grams per mole). It has no unit and its value is approximately 0.2727. It is used to convert the mass of CO2 into the mass of the carbon element it contains.

[0085] The total mineralized carbon consumed refers to the total mass of carbon consumed by microorganisms through aerobic respiration to convert organic carbon into CO2 from the start of fermentation to the present moment, expressed in kilograms. The value reflects the actual consumption of the carbon pool and increases monotonically as fermentation progresses.

[0086] The estimated remaining organic carbon (RCC) is obtained by subtracting the total amount of mineralized carbon from the total mass of organic carbon, expressed in kilograms. The value indicates the mass of organic carbon in the heap that has not yet been mineralized. A positive value indicates that there is still carbon available for microbial use, while a value close to zero indicates that the carbon source is nearing depletion. The larger the value, the lower the need for carbon replenishment.

[0087] This embodiment subtracts the initial total organic carbon mass from the total mineralized carbon consumed, calculated based on the cumulative CO2 release from the exhaust gas. This allows for the continuous estimation of the remaining organic carbon at the current moment without interrupting fermentation or damaging the pile structure. This estimate directly serves as the basis for subsequent carbon replenishment decisions, eliminating reliance on fixed schedules or empirical judgments and instead basing the carbon replenishment on the actual carbon consumption progress of the pile. This avoids the continuous deterioration of metabolic stress due to insufficient carbon replenishment, or waste and secondary pollution caused by excessive carbon replenishment. Furthermore, by utilizing existing exhaust gas CO2 concentration and ventilation flow data, indirect weighing of the organic carbon consumption process is achieved without additional hardware costs.

[0088] Considering the coupling relationship between the current carbon consumption rate (CO2 release rate) and the size of the remaining carbon pool (estimated remaining organic carbon): for the same amount of remaining carbon, a faster consumption rate indicates higher microbial activity, requiring a larger amount of carbon replenishment; conversely, a slower consumption rate indicates a lower carbon replenishment requirement. Simply comparing the absolute value of remaining carbon is meaningless because different fermentation batches have different initial carbon pools and consumption rates. Therefore, a relative indicator, the carbon consumption ratio, needs to be introduced, representing how long the remaining carbon can sustain the fermentation at the current consumption rate. By comparing this relative indicator with the reference carbon consumption ratio when metabolic stress first occurred, we can determine the sufficiency of the current carbon pool relative to the stress state, and thus calculate how much carbon needs to be replenished to restore the carbon consumption ratio to the reference level.

[0089] Specifically, the process for determining the amount of carbon supplementation is as follows: S405, during pulse ventilation, continuously collect the CO2 release rate at the current moment, with the unit of CO2 release rate being kilograms per hour. Find the moment when the carbon and nitrogen metabolic stress index or the degraded carbon and nitrogen metabolic stress index first exceeds the dynamic threshold from the historical change sequence from fermentation start to the current moment, and record this as the reference moment.

[0090] S406. Obtain the estimated residual organic carbon at the reference time and the median CO2 release rate within one complete time window before and after the reference time. The median is calculated by combining all CO2 release rate data within one complete time window before and one complete time window after the reference time. Divide the estimated residual organic carbon at the reference time by the median to obtain the reference carbon consumption ratio, which is expressed in hours. It should be noted that if the reference time is less than one complete time window from the fermentation start time, the carbon supplementation calculation for the current reference time is abandoned until a complete time window is reached between the reference time and the fermentation start time.

[0091] S407. Obtain the estimated remaining organic carbon at the current moment and the median CO2 release rate within one complete time window before and after the current moment. Calculate the current carbon consumption ratio, which is the estimated remaining organic carbon divided by the median current CO2 release rate. Compare the current carbon consumption ratio with the reference carbon consumption ratio. If the current carbon consumption ratio is greater than the reference carbon consumption ratio, set the carbon replenishment amount to zero. If the current carbon consumption ratio is less than the reference carbon consumption ratio, calculate the difference between the reference carbon consumption ratio and the current carbon consumption ratio, multiply the difference by the median current CO2 release rate to obtain the required carbon mass, measured in kilograms, which is used as the carbon replenishment amount for this operation.

[0092] It should be noted that the dynamic threshold is preset. For example, the initial value of the dynamic threshold is set as follows: Calculate the 90th quantile of the carbon and nitrogen metabolic stress index sequence from the first 24 sampling points (sampling period of 10 minutes) after fermentation starts, and use 1.5 times this quantile as the initial dynamic threshold; if there are fewer than 10 valid sampling points, the initial dynamic threshold is set to 3.0. Valid sampling points refer to those sampling points where, within the sampling period, all relevant sensors have not triggered fault judgments, the data is complete, and the values ​​are within a reasonable physical range. The "reasonable physical range" refers to the range of values ​​that each sensor may output under normal operating conditions, specifically as follows: the reasonable physical range for the core temperature sensor is -20℃ to 120℃; the reasonable physical range for the tail gas ammonia concentration sensor is 0 to 5000 mg / m³; the reasonable physical range for the tail gas CO2 concentration sensor is 0 to 20% (volume percentage); the reasonable physical range for the tail gas oxygen concentration sensor is 0 to 25% (volume percentage); the reasonable physical range for the pH sensor within the compost pile is 0 to 14; and the reasonable physical range for the ventilation flow sensor is 0 to the maximum design airflow of the ventilation system. These numerical limits are determined based on the measurement ranges of commonly used sensors in composting fermentation processes and the actual variation ranges of various parameters during composting, and are well-known to those skilled in the art.

[0093] After each full-layer turning (i.e., the end of a complete fermentation sub-cycle), the sequence of all carbon and nitrogen metabolic stress indices from the time of the previous turning to the time of the current turning is taken, and their 90th quantiles are calculated. 1.5 times this quantile is used as the dynamic threshold for the next sub-cycle. If none of the values ​​in this sequence exceed the current dynamic threshold, the dynamic threshold for the next sub-cycle remains unchanged. Furthermore, if a full-layer turning is never triggered during a complete fermentation cycle, the dynamic threshold will also remain unchanged.

[0094] The dynamic threshold has a lower limit of 1.5 and an upper limit of 6.0. If it exceeds these limits, it will be automatically truncated.

[0095] This embodiment determines the amount of carbon replenishment by calculating a reference carbon consumption ratio and the current carbon consumption ratio, and comparing their magnitudes. This eliminates the reliance on fixed empirical values ​​or absolute remaining carbon levels for carbon replenishment decisions, instead allowing for adaptive calibration based on the reactor's own metabolic history. When the current carbon consumption ratio is greater than the reference ratio, it indicates that the current remaining carbon is more abundant relative to the consumption rate than during the initial stress period, thus requiring no carbon replenishment. When the current carbon consumption ratio is less than the reference ratio, the required carbon mass is precisely calculated by multiplying the difference by the median current CO2 release rate. This relative comparison method automatically adapts to differences in carbon metabolism across different batches and stages, avoiding insufficient or excessive carbon replenishment, thereby bringing the carbon supply back above the critical level that previously caused metabolic stress.

[0096] After carbon supplementation, whether the carbon-nitrogen balance of the reactor stack has truly improved cannot be determined solely by theoretical calculations. It must be verified through a real-time indicator directly related to nitrogen loss. This is because the purpose of carbon supplementation is to promote microbial assimilation and utilization of more ammonium nitrogen, thereby reducing ammonia release. Changes in the ammonia concentration in the tail gas most directly reflect the effectiveness of carbon supplementation. However, single instantaneous ammonia concentrations are easily affected by sampling noise or local airflow interference, necessitating the use of window statistics to obtain robust judgments.

[0097] Meanwhile, carbon supplementation may result in three different outcomes: effective, insufficient, or excessive. Emergency response plans for excessive carbon supplementation also need to be considered. Since excessive carbon supplementation is often accompanied by intensified oxygen competition or localized anaerobic conditions, and the ventilation parameters (ventilation interval and airflow) corresponding to the lowest ammonia concentration point happen to be the most suitable configuration for oxygen supply at that time, using this as a temporary adjustment benchmark can quickly alleviate the negative effects of excessive supplementation.

[0098] The process for determining whether to maintain ventilation, add additional carbon, or determine excessive carbon addition based on the ammonia concentration in the exhaust gas is as follows: S408. After the carbon addition operation is completed, the ammonia concentration in the exhaust gas is continuously collected. A complete time window is extracted forward from the time the carbon addition operation is completed as the observation window. A complete time window of the same length is extracted backward from the time the carbon addition operation begins as the reference window.

[0099] S409. Calculate the median and interquartile range of the ammonia concentration in the exhaust gas within the baseline window, and the median and trend of the ammonia concentration in the exhaust gas within the observation window. Compare the median of the ammonia concentration in the exhaust gas within the observation window with the lower quartile of the ammonia concentration in the exhaust gas within the baseline window. The lower quartile is equal to the median of the ammonia concentration in the exhaust gas within the baseline window minus the interquartile range. If the median of the ammonia concentration in the exhaust gas within the observation window is higher than the median of the ammonia concentration in the baseline window, it is determined that the carbon supplementation is insufficient, and additional carbon supplementation is immediately initiated. The mass of carbon supplemented is equal to the amount of carbon supplemented in the first instance multiplied by the ratio of the median of the ammonia concentration in the exhaust gas within the observation window to the median of the ammonia concentration in the exhaust gas within the baseline window.

[0100] S410. If the median ammonia concentration in the exhaust gas within the observation window is not higher than the lower quartile of the ammonia concentration in the baseline window, then further judgment is made: if the median ammonia concentration in the exhaust gas within the observation window is lower than the lower quartile of the baseline window, and the trend of the ammonia concentration in the exhaust gas within the observation window shows a decrease followed by an increase, then it is determined that carbon supplementation is excessive. The decrease is defined as the minimum ammonia concentration in the exhaust gas within the observation window being lower than the lower quartile of the ammonia concentration in the baseline window, and the increase is defined as a positive average rate of change in the ammonia concentration in the exhaust gas from the moment the minimum value occurs to the end of the observation window.

[0101] S411. In other cases, carbon replenishment is deemed effective, and the current ventilation parameters are maintained.

[0102] The process of adjusting the ventilation interval after determining excessive carbon supplementation is as follows: The time interval is traced back from the moment the minimum ammonia concentration in the exhaust gas occurred within the observation window to the start time of the most recent ventilation before that moment; simultaneously, the single airflow is adjusted to the single airflow corresponding to the moment the minimum ammonia concentration occurred. For example, if the minimum ammonia concentration in the exhaust gas occurred at the 120th minute, and the most recent ventilation started at the 100th minute, the ventilation interval is adjusted to 20 minutes. If the moment the minimum concentration occurred coincides with the start time of a ventilation, the interval length is taken from the original set value of that ventilation interval.

[0103] After adjusting the duration of a full observation window, the ventilation parameters were restored by re-determining the ventilation interval and air volume based on the core temperature and exhaust gas oxygen concentration.

[0104] This embodiment compares the median and lower quartile of the tail gas ammonia concentration within two complete time windows before and after carbon supplementation, as well as the trend of change within the observation window. It can automatically distinguish between three different outcomes: effective carbon supplementation, insufficient carbon supplementation, and excessive carbon supplementation, and provide corresponding control actions for each. This closed-loop verification mechanism based on tail gas ammonia concentration feedback ensures that carbon supplementation is no longer a one-time open-loop control, but rather can be adaptively corrected based on the actual ammonia release response, thus truly achieving the process goal of preventing abrupt peaks in ammonia concentration. Especially when carbon supplementation is excessive, it can proactively adjust the ventilation interval and single-pass airflow back to the parameter values ​​corresponding to the moment when the tail gas ammonia concentration reaches its minimum. This retrospective emergency adjustment is more precise than blindly increasing ventilation or stopping carbon supplementation, and can restore the reactor to its normal state in a short time.

[0105] S5. After carbon replenishment is completed, full-layer turning is performed based on temperature change rate.

[0106] After carbon replenishment, although the carbon-nitrogen balance is improved, the spatial distribution of the added carbon source within the pile is often uneven. Simultaneously, oxygen, temperature, and moisture gradients may have emerged within the pile, leading to spatially uneven microbial activity. Without physical turning, the added carbon cannot be fully utilized by all microorganisms, and ammonia may still be released from specific weak points. However, the timing of turning cannot be arbitrarily chosen; turning too early will interrupt the microbial adaptation process after carbon replenishment, while turning too late will waste the benefits of carbon replenishment.

[0107] Temperature change rate is a direct indicator of the intensity of microbial metabolic heat production: when the temperature change rate changes from a positive to a negative value, it indicates that the peak of microbial heat production has passed and the pile begins to cool naturally; while a negative acceleration of the temperature change rate indicates that the cooling rate is accelerating (i.e., the temperature change rate is decreasing faster and faster). When both conditions are met simultaneously, it means that the metabolic peak caused by carbon supplementation has been completed, and the pile is about to enter a relatively stable stage. At this time, full-layer turning can evenly distribute the remaining carbon source and microbial community without interfering with the main metabolic processes. Therefore, the process of performing full-layer turning based on temperature change rate is as follows: continuously collect the core temperature at the current moment, calculate the temperature change rate in each sampling period (in degrees Celsius per hour), and further calculate the first derivative of the temperature change rate with time to obtain the acceleration of the temperature change rate (in degrees Celsius per hour squared).

[0108] Starting from the moment carbon replenishment is completed, the sign of the temperature change rate and the sign of the acceleration of the temperature change rate are continuously monitored. When the temperature change rate changes from a positive value to a negative value, and the acceleration of the temperature change rate is negative for several consecutive sampling periods, the execution condition of full-layer turning is triggered. The number of consecutive sampling periods is dynamically determined as follows: extract the number of sampling periods from the moment the temperature change rate first turns negative to the moment the acceleration of the temperature change rate first turns positive during the most recent complete turning period from positive to negative in historical data. This number of sampling periods is used as the number of consecutive sampling periods required for this determination.

[0109] It should be noted that before the first overhaul, the default number of consecutive sampling periods is 3. After the first overhaul, this parameter is updated based on the number of sampling periods elapsed from the first negative value of the temperature change rate to the first positive value of the temperature change rate acceleration before the overhaul, and is used for subsequent overhaul determination. If, after the temperature change rate turns from positive to negative before a certain overhaul, the temperature change rate acceleration never turns from negative to positive (i.e., remains negative until the overhaul is triggered), then the number of consecutive sampling periods is taken as the actual number of sampling periods experienced in this overhaul.

[0110] In addition, the default setting of 3 consecutive sampling periods is based on the fact that during the composting fermentation process, after the temperature change rate changes from positive to negative, its acceleration usually completes the process of changing from negative to positive within 2 to 5 sampling periods. Taking the middle value of 3 sampling periods as the continuous condition for the first turning of the pile can ensure the timeliness of turning the pile while avoiding false triggering caused by single sampling anomalies.

[0111] Upon triggering the execution conditions, the turning equipment is immediately activated to turn the entire pile over, bringing the bottom material to the surface and the surface material back into the interior. After turning, the fermentation membrane is re-covered and compacted for sealing. Simultaneously, the starting point of the sliding window used to calculate or downgrade the carbon and nitrogen metabolism stress index is reset to the turning completion time, and the integral zero point of the cumulative CO2 release is also reset to the turning completion time. The total amount of mineralized carbon consumed calculated based on the cumulative CO2 release before turning is retained as a historical cumulative value. The amount of newly mineralized carbon corresponding to the newly released CO2 after turning continues to accumulate based on this historical cumulative value.

[0112] It should be noted that during the turning process, the material turning and throwing alters the pore structure of the pile, which may temporarily release trapped gases (including CO2). This CO2 is not a new product of microbial metabolic activity. To avoid the CO2 release caused by the turning process itself being incorrectly included in the total amount of mineralized carbon consumed, the integral calculation of the cumulative CO2 release is suspended during the turning process. After the turning is completed, once the pile is re-covered with the fermentation film and compacted, and the exhaust gas emissions stabilize (based on the rate of change of exhaust gas CO2 concentration being less than a preset stability threshold for three consecutive sampling periods, defined as the absolute value of the rate of change of exhaust gas CO2 concentration being less than 0.1% (volume percentage) / sampling period for three consecutive sampling periods), the integral calculation of the cumulative CO2 release is resumed. The total amount of mineralized carbon consumed calculated based on the cumulative CO2 release before the turning is completed is retained as a historical cumulative value. The amount of newly mineralized carbon corresponding to the new CO2 release after the turning is completed continues to accumulate based on this historical cumulative value.

[0113] The first derivative of the temperature change rate over time represents the rate of change of the temperature change rate itself, i.e., the acceleration of the temperature change rate. It is obtained by subtracting the temperature change rate of the previous sampling period from the temperature change rate of the current sampling period, and then dividing by the sampling period duration. A positive value indicates that the temperature change rate is increasing, and a negative value indicates that the temperature change rate is decreasing, reflecting the inflection point in the heat generation or dissipation trend of the reactor. The sampling period is consistent with the fixed sampling period used for collecting other parameters throughout the text. For abnormal fluctuations in the temperature change rate occurring within a single sampling period, since the triggering of a negative value for the acceleration of the temperature change rate requires two consecutive sampling periods to meet the negative value condition, the impact of a single sampling anomaly on the judgment result can be reduced.

[0114] This embodiment uses the monitoring of the temperature change rate changing from positive to negative and the acceleration of the temperature change rate being continuously negative as the condition for triggering full-layer turning, achieving precise adaptive control of the turning timing. This triggering mechanism based on metabolic thermodynamic indicators ensures that the turning action occurs precisely at the turning point where the microbial active period ends after carbon supplementation and the pile naturally enters a cooling trend. This avoids premature turning that disrupts the ongoing carbon and nitrogen assimilation reaction, and also avoids late turning that could lead to localized hypoxia or uneven carbon source distribution causing secondary ammonia release. Simultaneously, after turning, the starting point of the sliding window and the integral zero point of the cumulative carbon dioxide release are reset, allowing subsequent calculations of the carbon and nitrogen metabolic stress index and the estimation of remaining organic carbon to begin from a new homogeneous state. This eliminates calculation biases caused by inhomogeneities within the pile before turning, ensuring the long-term continuity of the entire process optimization control method.

[0115] It should be noted that any sensor is considered faulty if it receives no data or its value exceeds the physical range for five consecutive sampling cycles. When the core temperature sensor malfunctions, all control measures are stopped and an alarm is triggered; when the exhaust ammonia concentration sensor malfunctions, carbon supplementation adjustments are suspended, and the previous effective carbon supplementation level is maintained; when the pH sensor malfunctions, a downgraded carbon and nitrogen metabolism stress index is forcibly used; when the CO2 or oxygen concentration sensor malfunctions, ventilation parameters remain at the previous effective value. After any sensor recovers, it must have stable data for three consecutive sampling cycles before it can rejoin the control system.

[0116] Furthermore, to verify the inhibitory effect of this invention on the ammonia release mutation peak, a control group and an experimental group were set up for comparative verification. The control group adopted a fixed carbon supplementation strategy, with the carbon supplementation trigger time fixed at 96 h, while the experimental group adopted the dynamic carbon supplementation strategy described in this invention, with other fermentation process conditions remaining consistent. Both groups collected tail gas ammonia concentrations at the same time points, recording concentration changes from 72 h to 132 h. The results are as follows (see Table 1):

[0117] Table 1. Data on NH3 concentration over time under fixed and dynamic carbon supplementation strategies.

[0118]

[0119] The rate of change of ammonia concentration As a quantitative indicator for evaluating the intensity of peaks, the results showed that the ammonia concentration in the control group rose sharply after carbon supplementation, exhibiting a typical abrupt spike; while the ammonia concentration in the experimental group changed gradually throughout the observation period, without any short-term surge.

[0120] As attached Figure 4As shown, the ammonia concentration curve in the control group exhibited a significant sharp peak after 96 hours, rapidly increasing from 135 to 360, while the curve in the experimental group maintained a smooth upward trend throughout, slowly increasing from 128 to 151 without any abnormal inflection points or peaks. The above comparative data clearly demonstrate that this invention, through dynamic metabolic state identification and adaptive carbon supplementation regulation, can effectively suppress abrupt peaks in ammonia release, keeping ammonia concentration changes within a controllable range.

[0121] It should be noted that the abrupt peak of ammonia concentration is mathematically defined as a local maximum point on the curve of ammonia concentration versus time. According to the fundamental principles of differential calculus, any continuously differentiable function at its local maximum point must satisfy the condition on the left side of that point. Greater than 0, right side Less than 0. Therefore, the transition from positive to negative is a common characteristic of all peaks. However, the essential difference between abrupt peaks and normal fluctuation peaks lies not in whether there is a transition from positive to negative, but in the time preceding the transition. The amplitude and its variation.

[0122] Taking the comparative experimental data as an example (see Table 1 and...), Figure 4 ):

[0123] Fixed carbon replenishment strategy: During the period from 96h to 114h, the ammonia concentration increased sharply from 135. Correspondingly, It remained a large positive value within the 96h-108h range and increased periodically; within the 108h-114h range... It abruptly turned into a large negative value, and the concentration curve showed a sharp narrow peak at 114h, which is a typical abrupt peak shape.

[0124] Dynamic carbon replenishment strategy: Throughout the 72-132 hour period, the ammonia concentration slowly increased from 110 to 151 and then gradually decreased to 138. Correspondingly, The value remained low throughout, and although it turned negative after 126 hours, the value before turning negative was lower. The amplitude is small, and the absolute value of the rate after turning negative is also small. The concentration curve has a broad and gentle dome shape, which is a normal metabolic decline and does not belong to a sudden peak.

[0125] The above comparison shows that the fixed carbon replenishment group experienced a process of sustained large positive rates and increasing periodically before the peak, while the dynamic carbon replenishment group maintained a low and stable rate throughout the entire process. There is an essential difference in the rate pattern between the two.

[0126] Based on the above mechanism, the present invention addresses... The monitoring can determine the peak value of mutation without setting a fixed numerical threshold.

[0127] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0128] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0129] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0130] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0131] Finally, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing and controlling the composting and fermentation process of livestock and poultry manure, characterized in that, Includes the following steps: Construct baseline medians and baseline tolerances for the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trends within the reactor core. Update the baseline medians and baseline tolerances when the temperature difference between the reactor core temperature and the ambient temperature exceeds a temperature threshold and lasts for a duration longer than a preset duration. When the pH value in the pile does not change abruptly, the carbon and nitrogen metabolism stress index is determined based on the offset of the baseline median and the baseline tolerance, combined with the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend. Otherwise, the pH change trend is excluded and the degraded carbon and nitrogen metabolism stress index is calculated. Once the carbon and nitrogen metabolism stress index is determined to be downgraded or exceeds the dynamic threshold, the ventilation interval and air volume are determined based on the core temperature and exhaust gas oxygen concentration. When ventilating based on ventilation interval and air volume, determine the estimated value of residual organic carbon, combine the carbon and nitrogen metabolism stress index or the downgraded carbon and nitrogen metabolism stress index with the CO2 release rate to determine the amount of carbon supplementation, and at the same time determine whether to maintain ventilation, add carbon supplementation, or determine excessive carbon supplementation and adjust the ventilation interval based on the ammonia concentration in the exhaust gas. After carbon replenishment is completed, full-layer turning is performed based on temperature change rate.

2. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of constructing the baseline median and baseline tolerance is as follows: During the initial stage after the start of composting fermentation, the core temperature, tail gas ammonia concentration, CO2 release rate and pH value in the compost were continuously collected at a fixed sampling period. The temperature change rate, ammonia concentration gradient, and pH change trend at each sampling time are calculated based on the collected time-series data. The moment when the core temperature first reaches the set temperature is taken as the end point of the initial stage. If the core temperature never reaches the set temperature, the preset time after startup is taken as the end point. Calculate the median and interquartile range of the temperature change rate, ammonia concentration gradient, CO2 release rate and pH change trend in the initial stage respectively. Use the median as the baseline median of the corresponding parameter and the interquartile range as the baseline tolerance of the corresponding parameter.

3. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The criterion for determining that the pH value within the pile has not changed abruptly is: During the composting fermentation process, the pH value inside the pile is continuously collected. The pH value at the current sampling time is subtracted from the pH value at the previous sampling time to obtain the pH value change. If the absolute value of the pH value change is greater than the preset jump threshold, it is determined that the pH value inside the pile has jumped; otherwise, it is determined that no jump has occurred.

4. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of determining the carbon and nitrogen metabolic stress index is as follows: Calculate the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend at the current moment; Subtract the corresponding current baseline median from the temperature change rate, ammonia concentration gradient, CO2 release rate, and pH change trend to obtain four offsets; Divide each offset by its corresponding current baseline tolerance to obtain four offset intensities. Sum the squares of the four offset intensities and then take the square root to obtain the carbon and nitrogen metabolic stress index. The process for calculating the downgraded carbon and nitrogen metabolic stress index is as follows: After removing the pH change trend, the temperature change rate, ammonia concentration gradient and CO2 release rate are each subtracted from the corresponding current baseline median to obtain three offsets; Divide each offset by its corresponding current baseline tolerance to obtain three offset intensities. Sum the squares of the three offset intensities and then take the square root to obtain the degraded carbon and nitrogen metabolic stress index.

5. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of determining ventilation intervals and airflow based on core temperature and exhaust gas oxygen concentration is as follows: Within the most recent complete time window, multiple sampling points were recorded to record the change of core temperature over time, and the average rate of change of core temperature was calculated. When the average rate of change is positive, the average duration of the three most recent consecutive core temperature rise processes in historical data is used as the ventilation interval; when the average rate of change is negative, the average duration of the three most recent consecutive core temperature fall processes in historical data is used as the ventilation interval; when the average rate of change is zero, the previous ventilation interval remains unchanged. Calculate the difference between the current exhaust oxygen concentration and the average exhaust oxygen concentration over a past complete time window; When the difference is positive, the airflow is set to the average airflow during the period of decreasing exhaust oxygen concentration in the past complete time window multiplied by the ratio of the current exhaust oxygen concentration to the minimum exhaust oxygen concentration in the past complete time window; when the difference is negative, the airflow is set to the average airflow during the period of increasing exhaust oxygen concentration in the past complete time window multiplied by the ratio of the maximum exhaust oxygen concentration in the past complete time window to the current exhaust oxygen concentration; when the difference is zero, the previous airflow remains unchanged.

6. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of determining the estimated value of residual organic carbon is as follows: Before starting composting fermentation, the total dry matter mass of the mixture is calculated based on the mixing ratio of livestock and poultry manure and auxiliary materials and their respective dry matter mass. Then, the total organic carbon mass is obtained by multiplying the mass fraction of organic carbon in each raw material by the corresponding dry matter mass and summing the results. During the composting fermentation process, the CO2 concentration and ventilation flow rate of the exhaust gas are continuously collected. The CO2 concentration is divided by 100 and then multiplied by the ventilation flow rate to obtain the CO2 volume flow rate. The cumulative CO2 release is then obtained by integrating over time. Multiply the cumulative CO2 release by the density of carbon dioxide at standard atmospheric pressure to obtain the cumulative CO2 mass, then multiply by the mass conversion constant between carbon and carbon dioxide to obtain the total amount of mineralized carbon consumed. The estimated value of remaining organic carbon is obtained by subtracting the total amount of mineralized carbon from the total organic carbon mass.

7. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of determining the amount of carbon to be added is as follows: Find the moment when the carbon and nitrogen metabolism stress index or the degraded carbon and nitrogen metabolism stress index first exceeds the dynamic threshold from the historical change sequence of the carbon and nitrogen metabolism stress index from the start of fermentation to the present moment, and record it as the reference moment. Obtain the estimated residual organic carbon at the reference time and the median of the CO2 release rate within one full time window before and after the reference time. Divide the estimated residual organic carbon at the reference time by the median to obtain the reference carbon consumption ratio. Calculate the current carbon consumption ratio. If the current carbon consumption ratio is greater than the reference carbon consumption ratio, set the carbon replenishment amount to zero. If the current carbon consumption ratio is less than the reference carbon consumption ratio, calculate the difference between the reference carbon consumption ratio and the current carbon consumption ratio, multiply the difference by the median of the current CO2 release rate, and obtain the amount of carbon that needs to be replenished.

8. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process for determining whether to maintain ventilation, add additional carbon, or determine excessive carbon addition based on the ammonia concentration in the exhaust gas is as follows: Starting from the completion time of the carbon replenishment operation, a complete time window is extracted forward as the observation window; starting from the start time of the carbon replenishment operation, a complete time window of the same length is extracted backward as the reference window. If the median ammonia concentration in the exhaust gas within the observation window is higher than the median ammonia concentration in the exhaust gas within the baseline window, then carbon supplementation is deemed insufficient. If the median of the ammonia concentration in the exhaust gas within the observation window is lower than the lower quartile of the ammonia concentration in the exhaust gas within the baseline window, and the trend of the ammonia concentration in the exhaust gas within the observation window is first decreasing and then increasing, then it is determined that the carbon supplementation is excessive. Otherwise, the carbon replenishment is deemed effective, and the current pulse ventilation parameters are maintained unchanged.

9. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 8, characterized in that, The process of adjusting the ventilation interval after determining that excessive carbon supplementation has occurred is as follows: The time length from the moment the minimum ammonia concentration in the exhaust gas occurred to the start time of the most recent ventilation before that moment is calculated; at the same time, the single air volume is adjusted to the single air volume corresponding to the moment the minimum ammonia concentration in the exhaust gas occurred.

10. The method for optimizing and controlling the composting and fermentation process of livestock and poultry manure according to claim 1, characterized in that, The process of performing full-layer turning based on temperature change rate is as follows: Starting from the moment carbon replenishment is completed, when the temperature change rate changes from a positive value to a negative value, and the acceleration of the temperature change rate is negative for several consecutive sampling periods, the execution condition for full-layer overturning is triggered. Once the execution conditions are triggered, the turning equipment is immediately started to turn the entire pile over, turning the bottom material to the surface and the surface material into the interior. After the turning is completed, the fermentation film is re-covered and compacted for sealing. At the same time, the starting point of the sliding window used to calculate or downgrade the carbon and nitrogen metabolism stress index is reset to the time when the turning is completed, and the integral zero point of the cumulative CO2 release is reset to the time when the turning is completed.

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