An automatic parameter regulating system for organic wastewater treatment

Abstract

The application relates to the technical field of organic wastewater treatment, and discloses an automatic parameter regulation and control system for organic wastewater treatment, which comprises the following steps: collecting stress, viscosity and bubble operation state through a rheological sensor and an ultrasonic probe, quantifying boundary liquid film thickness and calculating stress relaxation time, and then constructing a time-space mismatch time constant; combining dissolved oxygen probe data to reversely deduce a real oxygen consumption rate of a microhabitat, and calculating a limit turbulent kinetic energy dissipation rate required by a tearing interface; finally, the limit turbulent kinetic energy dissipation rate is converted into a targeted gas flow, and a blow equipment is controlled after superimposing a feedforward compensation amount.

Description

Technical Field

[0001] This invention relates to the field of organic wastewater treatment technology, and more specifically, to an automated parameter control system for organic wastewater treatment. Background Technology

[0002] In the field of organic wastewater treatment, the degradation reaction zone is typically a highly heterogeneous fluid system interwoven with a gas phase (aeration microbubbles), a liquid phase (dissolved organic matter in aqueous solution), and a solid phase (porous microbial flocs). When dealing with high-concentration organic matter shock loads, the microbial community continuously secretes large amounts of extracellular polymers. The extensive interweaving of these polymers transforms the fluid within the microenvironment into a non-Newtonian fluid exhibiting significant viscoelastic properties. Currently, conventional automated control schemes generally rely on empirical thresholds or conventional PID proportional-integral parameters for adjustment, often determining oxygen supply sufficiency by monitoring the apparent dissolved oxygen concentration of the macroscopic water body. However, due to the intrinsic stress relaxation phenomenon in viscoelastic fluid networks, when the control system commands increased aeration or mechanical stirring torque to break the gas-liquid interface resistance, there is a significant hysteresis period in the disentanglement and deformation of the viscous liquid film. During this period, the high-viscosity liquid film surrounding the porous flocs not only fails to rupture immediately but also anchors the microbubbles outside the boundary layer, substantially blocking the permeation channels within the micropores. At this point, the apparent dissolved oxygen level in the macroscopic water body rises because the oxygen has not been consumed, and conventional monitoring equipment is prone to misinterpreting this as sufficient oxygen supply. However, the microorganisms trapped inside the flocs are actually in a state of anaerobic asphyxiation. Existing control systems struggle to identify and eliminate this reverse mass transfer hindrance caused by the mismatch between micro-interface mass transfer lag and macroscopic mechanical work frequency, which can easily lead to the system injecting energy at the wrong time, resulting in severe ineffective energy dissipation. Summary of the Invention

[0003] This invention provides an automated parameter control system for organic wastewater treatment, which solves the technical problems mentioned in the background art.

[0004] This invention provides an automated parameter control system for organic wastewater treatment, comprising a high-frequency torque rheometer, a Doppler ultrasonic probe, a dissolved oxygen probe, a blower, a storage module, and a controller; the storage module pre-stores liquid phase density, oxygen diffusion coefficient, saturated dissolved oxygen concentration, atmospheric pressure, gravitational acceleration, still water depth, and reactor volume; the controller executes:

[0005] The rheological sensor is controlled to collect transient shear stress and shear strain rate, and to calculate transient apparent viscosity and stress relaxation time.

[0006] The ultrasonic probe is controlled to obtain the bubble diameter and rising velocity. Combined with the liquid phase density and transient apparent viscosity, the boundary liquid film thickness is calculated.

[0007] Combining the oxygen diffusion coefficient and stress relaxation time, the time constant is constructed using the boundary liquid film thickness;

[0008] The dissolved oxygen probe is controlled to collect real-time dissolved oxygen concentration, and the actual oxygen consumption rate is restored by combining the saturated dissolved oxygen concentration with the time constant.

[0009] Using the actual oxygen consumption rate, saturated dissolved oxygen concentration, real-time dissolved oxygen concentration, transient apparent viscosity and liquid density, the limiting dissipation rate is derived.

[0010] Based on the atmospheric pressure, gravitational acceleration, still water depth, and reactor volume, the limiting dissipation rate is converted into the target gas flow rate.

[0011] Calculate the time partial derivative of the target gas flow rate, combine it with the time constant to generate an overshoot, add it to the target gas flow rate, and send a compensation command to the blower.

[0012] Furthermore, the calculation of transient apparent viscosity and stress relaxation time includes:

[0013] The transient apparent viscosity is obtained by dividing the transient shear stress by the shear strain rate.

[0014] The instantaneous stress decay rate is obtained by performing a partial derivative of the transient shear stress with respect to time.

[0015] The stress relaxation time is obtained by dividing the transient shear stress by the instantaneous stress decay rate and taking the absolute value.

[0016] Furthermore, the process of solving for the boundary liquid film thickness includes:

[0017] Multiplying the transient apparent viscosity by the bubble diameter yields the dynamic lag product;

[0018] Multiplying the liquid phase density by the upward velocity yields the momentum-convection product;

[0019] The boundary liquid film thickness is obtained by dividing the product of dynamic resistance by the product of momentum convection and taking the square root.

[0020] Furthermore, the construction time constant includes:

[0021] The squared value of the spatial barrier thickness is obtained by squaring the thickness of the boundary liquid film.

[0022] Divide the squared value of the spatial barrier thickness by the oxygen diffusion coefficient to calculate the molecular penetration delay time.

[0023] The time constant is constructed by adding the molecular permeation delay time to the stress relaxation time.

[0024] Furthermore, the restoration of the true oxygen consumption rate includes:

[0025] The absolute value of the instantaneous time partial derivative of dissolved oxygen is obtained by calculating the partial derivative of the real-time dissolved oxygen concentration with respect to time and taking the absolute value.

[0026] The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration.

[0027] Dividing the concentration-driven difference by the time constant yields the implicit oxygen debt flux;

[0028] The absolute value of the instantaneous time partial derivative of dissolved oxygen is added to the implicit oxygen debt flux to reconstruct the true oxygen consumption rate.

[0029] Furthermore, the derivation of the limiting dissipation rate includes:

[0030] The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration.

[0031] Divide the actual oxygen consumption rate by the concentration-driven difference, and square the resulting quotient to obtain the mass transfer frequency driving term.

[0032] Divide the transient apparent viscosity by the liquid phase density to obtain the momentum-viscosity drag term;

[0033] The limiting dissipation rate is derived by multiplying the mass transfer frequency driving term by the momentum viscous resistance term.

[0034] Furthermore, the step of converting the limiting dissipation rate into a target gas flow rate includes:

[0035] Multiplying the limiting dissipation rate, the liquid phase density, and the reactor volume together yields the total turbulent mechanical power.

[0036] The hydrostatic pressure difference is obtained by multiplying the liquid phase density, the gravitational acceleration, and the still water depth.

[0037] Divide the hydrostatic pressure difference by the atmospheric pressure and add one, then take the natural logarithm of the sum to obtain the isothermal expansion ratio.

[0038] Multiplying the isothermal expansion ratio by the atmospheric pressure yields the isothermal expansion ratio work.

[0039] The target gas flow rate is calculated by dividing the total power of the turbulent machinery by the specific work of the isothermal expansion.

[0040] Furthermore, the step of calculating the time partial derivative of the target gas flow rate, combining it with the time constant to generate an overshoot, adding it to the target gas flow rate, and sending a compensation command to the blower equipment includes:

[0041] The time partial derivative is obtained by performing a partial derivative calculation on the target gas flow rate with respect to time.

[0042] Multiplying the time partial derivative by the time constant yields the overshoot.

[0043] The target gas flow rate is added to the overshoot to generate the compensation command, which is then sent to the blower.

[0044] The beneficial effects of this invention are as follows: Starting from the rheological properties of fluids and the hysteresis phenomenon at multiphase interfaces, the system quantitatively analyzes the mass transfer damping phenomenon in viscoelastic media environments. By collecting real-time monitoring data such as transient fluid strain, bubble slip velocity, and dissolved oxygen concentration, the kinetic energy boundary required to overcome the interfacial mass transfer barrier is derived, and feedforward compensation is implemented for the output. This invention eliminates the time lag misalignment between macroscopic operational commands and microscopic aerobic metabolism, effectively avoiding ineffective energy dissipation caused by blindly increasing mechanical work, and significantly improving the system's mass transfer efficiency and operational stability. Attached Figure Description

[0045] Figure 1 This is a flowchart of the controller operation of an automated parameter control system for organic wastewater treatment according to the present invention. Detailed Implementation

[0046] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0047] This embodiment provides an automated parameter control system for organic wastewater treatment, including a high-frequency torque rheology sensor, a Doppler ultrasonic probe, a dissolved oxygen probe, a blower, a storage module, and a controller. The storage module pre-stores liquid phase density, oxygen diffusion coefficient, saturated dissolved oxygen concentration, atmospheric pressure, gravitational acceleration, still water depth, and reactor volume. The system software is divided into a data acquisition module, a data preprocessing module, a core calculation module, a control output module, a fault diagnosis module, and a parameter management module. These modules interact via shared memory. The control output module has higher priority than all other modules to ensure real-time control commands. The system's core algorithm has a 100-millisecond runtime. The data cache uses a 1000-byte circular buffer to retain historical data from the most recent 100 seconds. Historical data is stored in binary format, including timestamps and corresponding parameter values.

[0048] like Figure 1 As shown, an automated parameter control system for organic wastewater treatment includes a high-frequency torque rheometer, a Doppler ultrasonic probe, a dissolved oxygen probe, a blower, a storage module, and a controller. The storage module pre-stores liquid phase density, oxygen diffusion coefficient, saturated dissolved oxygen concentration, atmospheric pressure, gravitational acceleration, still water depth, and reactor volume. The controller executes:

[0049] The rheological sensor is controlled to collect transient shear stress and shear strain rate, and to calculate transient apparent viscosity and stress relaxation time.

[0050] The ultrasonic probe is controlled to obtain the bubble diameter and rising velocity. Combined with the liquid phase density and transient apparent viscosity, the boundary liquid film thickness is calculated.

[0051] Combining the oxygen diffusion coefficient and stress relaxation time, the time constant is constructed using the boundary liquid film thickness;

[0052] The dissolved oxygen probe is controlled to collect real-time dissolved oxygen concentration, and the actual oxygen consumption rate is restored by combining the saturated dissolved oxygen concentration with the time constant.

[0053] Using the actual oxygen consumption rate, saturated dissolved oxygen concentration, real-time dissolved oxygen concentration, transient apparent viscosity and liquid density, the limiting dissipation rate is derived.

[0054] Based on the atmospheric pressure, gravitational acceleration, still water depth, and reactor volume, the limiting dissipation rate is converted into the target gas flow rate.

[0055] Calculate the time partial derivative of the target gas flow rate, combine it with the time constant to generate an overshoot, add it to the target gas flow rate, and send a compensation command to the blower.

[0056] Upon system startup, a complete initialization process is executed. All state variables are initialized to their minimum values ​​within the physically reasonable range. The initial stress relaxation time is 0.01 seconds, the initial boundary liquid film thickness is 10 micrometers, the initial time constant is 0.02 seconds, and the initial true oxygen consumption rate is 10. -6 Kilograms per cubic meter per second. After system startup, it enters a data preheating phase with a preheating period of 30 seconds. During the preheating phase, only data is collected without any control output. After 300 valid sampling points are collected, the core calculation module and control output module are activated. The control output adopts a gradual increase strategy, with the initial aeration flow rate being 30% of the blower's rated flow rate, linearly increasing to the calculated value within 60 seconds to avoid violent fluctuations during system startup.

[0057] All sensors employ a hardware pulse-triggered synchronization method, achieving a synchronization accuracy better than 1 millisecond and a timestamp accuracy in the microsecond range. During data acquisition, all sensor outputs are forcibly converted to International Units (SI), with conversion coefficients pre-stored in the parameter management module. After conversion, a unit consistency check is performed; if the check fails, the data point is discarded and a fault log is recorded. After all parameters are calculated, a physical reasonable range check is performed; if the value exceeds the range, the valid parameter value from the previous moment is used as a replacement, and an anomaly log is recorded.

[0058] A high-frequency torque rheology sensor is used to collect transient shear stress and shear strain rate, and to calculate transient apparent viscosity and stress relaxation time. The sensor is installed at the center of the reactor's aeration zone, at least 1 meter from the tank wall and 0.5 meters vertically from the aeration head. It operates in a fixed shear rate mode, with a shear rate setting range of 10 to 1000 Hz. The sensor is calibrated every 3 months using standard viscosity oil. The calibration procedure involves sequentially measuring with standard viscosity oils of 1 mPa·s, 10 mPa·s, and 100 mPa·s, linearly fitting the measured values ​​to the standard values, obtaining calibration coefficients, and storing them in the parameter management module.

[0059] Dividing the transient shear stress by the shear strain rate yields the transient apparent viscosity. The calculation formula is:

[0060]

[0061] in, The transient shear stress, measured in Pascals, is acquired by a high-frequency torque rheometer at a sampling frequency of 10 Hz. After acquisition, it is first filtered by a sliding median filter with a window length of 5 to remove peak noise, and then smoothed by a third-order polynomial Savitzky-Golay filter with a window length of 7. The shear strain rate, measured in seconds, is output synchronously from a high-frequency torque rheometer and transient shear stress. ρ is the transient apparent viscosity, measured in Pascal-seconds, characterizing the viscous properties of the wastewater fluid at the current moment. When When less than or equal to 0.1 per second, Take the valid value from the previous time step; when When less than 0.001 pascals second or greater than 1 pascal second, Take the corresponding boundary value.

[0062] The instantaneous stress decay rate is obtained by taking the ordinary differential derivative of the transient shear stress with respect to time. The stress relaxation time is then obtained by dividing the transient shear stress by the instantaneous stress decay rate and taking its absolute value. The calculation formula is as follows:

[0063]

[0064] in, The instantaneous stress decay rate, expressed in Pascals per second, is calculated using the central difference method to determine the discrete derivative. For intermediate sampling points, the calculation formula is as follows: ,in The sampling period is 0.1 seconds; for the first sampling point, the forward difference method is used for calculation, and the calculation formula is as follows: For the last sampling point, the backward difference method is used for calculation, and the calculation formula is as follows: . Stress relaxation time, expressed in seconds, characterizes the time required for the viscoelastic network in wastewater to untangle, reflecting the elastic properties of the fluid. When... Less than 10⁻ 6 Pascal per second Take the valid value from the previous time step; when When less than 0.01 seconds or greater than 100 seconds, Take the corresponding boundary value.

[0065] The Doppler ultrasonic probe was used to acquire bubble diameter and rising velocity. Combined with liquid density and transient apparent viscosity, the boundary liquid film thickness was calculated. The Doppler ultrasonic probe was installed above the aeration zone of the reactor at a 45-degree angle to the horizontal plane, with a sampling depth of 0.3 to 0.7 meters and a beam coverage area of ​​a circular region with a diameter of 0.2 meters. The sensor was calibrated every 6 months using a standard bubble generator. The calibration process involved generating standard bubbles with diameters of 0.1 mm, 1 mm, and 5 mm, measuring the bubble diameter and rising velocity, comparing the measured values ​​with the standard values, and adjusting the probe gain and threshold parameters accordingly.

[0066] Multiplying the transient apparent viscosity by the bubble diameter yields the dynamic retardation product. The bubble diameter, in meters, is the volume-weighted average bubble diameter, obtained from bubble echo signals acquired by a Doppler ultrasonic probe through particle size statistical analysis over a 1-second interval. The calculation formula is as follows:

[0067]

[0068] in, For the first The diameter of each bubble, For diameter is The number of bubbles, This represents the total number of bubbles detected within the statistical interval. Abnormal bubbles with a diameter less than 10 micrometers or greater than 10 millimeters are excluded during the statistical analysis. When the number of valid bubbles within the statistical interval is less than 10, [the following is considered a valid count]. Take the valid value from the previous moment.

[0069] Multiplying the liquid density by the upward velocity yields the momentum-convection product. Here, the liquid density... The unit is kilograms per cubic meter, pre-stored in the storage module with an initial value of 1000 kilograms per cubic meter. This value is adjusted in real-time based on wastewater temperature and concentration using the following formula: ,in The density of pure water at 20 degrees Celsius. For real-time water temperature, The concentration of chemical oxygen demand (COD) in the wastewater is given. The rising velocity is the average rising velocity of the bubbles, measured in meters per second, calculated from the Doppler frequency shift of the bubbles detected by a Doppler ultrasonic probe. The calculation formula is as follows: ,in For Doppler frequency shift, The speed of sound in water, The probe's transmission frequency, The installation angle for the probe.

[0070] The boundary liquid film thickness is obtained by dividing the product of dynamic resistance by the product of momentum and convection and then taking the square root. The calculation formula is as follows:

[0071]

[0072] in, For the rate of ascent, The boundary liquid film thickness, measured in meters, characterizes the thickness of the viscous boundary layer between the bubble surface and the bulk liquid phase, and is a key parameter affecting gas-liquid mass transfer efficiency. When less than or equal to 10⁻³ kg per square meter per second, Take the valid value from the previous time step; when When smaller than 1 micrometer or larger than 5 millimeters, Take the corresponding boundary value.

[0073] By combining the oxygen diffusion coefficient and stress relaxation time, the time constant is constructed using the boundary liquid film thickness.

[0074] The thickness of the boundary liquid film is squared to obtain the squared value of the spatial barrier thickness.

[0075] The molecular permeation delay time is calculated by dividing the square of the space barrier thickness by the oxygen diffusion coefficient. Here, the oxygen diffusion coefficient... The unit is square meters per second, pre-stored in the storage module, with an initial value of 2.1 × 10⁻⁶. -9 Square meters per second, adjusted in real time according to water temperature, the adjustment formula is: ,in This is the standard diffusion coefficient of oxygen in water at 20 degrees Celsius. The molecular permeation delay time, measured in seconds, characterizes the average time required for oxygen molecules to diffuse through the boundary liquid film.

[0076] The time constant is constructed by adding the molecular permeation delay time to the stress relaxation time. The calculation formula is as follows:

[0077]

[0078] in, The time constant, expressed in seconds, combines the hysteresis of oxygen molecule diffusion and the hysteresis of fluid stress relaxation, characterizing the total time delay of the mass transfer process at the micro-interface. When the time is less than 0.01 seconds or greater than 200 seconds, Take the corresponding boundary value.

[0079] The dissolved oxygen probe is used to collect real-time dissolved oxygen concentration. Combined with the saturated dissolved oxygen concentration and time constant, the true oxygen consumption rate is reconstructed. The dissolved oxygen probe is installed downstream of the reactor's aeration zone, at least 2 meters from the aeration head to avoid direct impact of air bubbles on the probe. The horizontal distance between the probe and the high-frequency torque rheometer is 1 meter. The sensor calibration cycle is one month. Zero-point calibration is performed using sodium sulfite solution, and span calibration is performed using air-saturated water. The calibration procedure is as follows: place the probe in sodium sulfite solution, wait for the reading to stabilize, set the zero point, then place the probe in stirred air-saturated water, wait for the reading to stabilize, and then set the span value.

[0080] The absolute value of the instantaneous time partial derivative of dissolved oxygen is obtained by performing ordinary differential derivative calculation with respect to time on the real-time dissolved oxygen concentration and taking the absolute value. Wherein, the real-time dissolved oxygen concentration... The unit is milligrams per liter. Converting to kilograms per cubic meter and then substituting the values, the conversion factor is 1 milligram per liter equals 10. -3 Kilograms per cubic meter were synchronously collected by a dissolved oxygen probe at a sampling frequency of 10 Hz. After collection, the samples were first filtered by a sliding median filter with a window length of 5 to remove spike noise, and then smoothed using a third-order polynomial Savitzky-Golay filter with a window length of 7. The instantaneous time partial derivative of dissolved oxygen was calculated using the central difference method, in a manner consistent with the calculation method for the instantaneous attenuation rate of stress.

[0081] The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration. Here, the saturated dissolved oxygen concentration... The unit is milligrams per liter, which is converted to kilograms per cubic meter and then used for calculation. The calculation is dynamically adjusted based on real-time water temperature and atmospheric pressure. The calculation formula is as follows: ,in This represents the saturated vapor pressure at the corresponding temperature. The concentration drive difference, expressed in kilograms per cubic meter, characterizes the driving force of the concentration gradient that drives oxygen diffusion from the bubbles to the bulk liquid phase. When the concentration drive difference is less than or equal to 0, the concentration drive difference is taken as 10. -6 kilograms per cubic meter.

[0082] Dividing the concentration-driven difference by the time constant yields the implicit oxygen debt flux. The implicit oxygen debt flux, measured in kilograms per cubic meter per second, characterizes the rate of oxygen consumption that is not detected by the dissolved oxygen probe due to mass transfer lag, reflecting the unmonitored oxygen demand generated by the actual metabolic activities of the microbial community.

[0083] The true oxygen consumption rate is obtained by adding the absolute value of the instantaneous partial derivative of dissolved oxygen over time to the implicit oxygen debt flux. The calculation formula is as follows:

[0084]

[0085] in, This is the instantaneous time derivative of dissolved oxygen. This represents the true oxygen consumption rate, expressed in kilograms per cubic meter per second, accurately reflecting the actual metabolic oxygen consumption rate of the microbial community and eliminating monitoring errors caused by mass transfer lag. Less than 10 -6 kilograms per cubic meter per second or greater than 10 -3 kilograms per cubic meter per second Take the corresponding boundary value.

[0086] The limiting dissipation rate is derived using the actual oxygen consumption rate, saturated dissolved oxygen concentration, real-time dissolved oxygen concentration, transient apparent viscosity, and liquid phase density.

[0087] The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration.

[0088] Divide the actual oxygen consumption rate by the concentration-driven difference, and square the quotient to obtain the mass transfer frequency driving term. The mass transfer frequency driving term is expressed in units of square seconds and represents the gas-liquid mass transfer frequency required to meet the actual oxygen consumption rate.

[0089] Dividing the transient apparent viscosity by the liquid phase density yields the momentum-viscosity drag term. The momentum-viscosity drag term, measured in square meters per second, characterizes the drag effect of fluid viscosity on turbulent motion.

[0090] Multiplying the mass transfer frequency driving term by the momentum-viscous drag term, and then multiplying by the mass transfer efficiency correction factor, the limiting dissipation rate is derived. The calculation formula is as follows:

[0091]

[0092] in, The limiting dissipation rate, expressed in cubic seconds per square meter, represents the minimum turbulent kinetic energy dissipation rate required to tear the boundary liquid film, break the mass transfer barrier, and achieve effective gas-liquid mass transfer. The mass transfer efficiency correction factor is dimensionless and ranges from 0.1 to 10. It is tuned based on the reactor configuration, aeration head type, and sludge concentration, with an initial value of 1.0. The tuning is performed using the decay curve method, and the tuning steps are gradual adjustments. The value makes the dissolved oxygen concentration decrease ratio 4:1. When Less than 10 -6 When the interval is 1 square meter per cubic second or greater than 1 square meter per cubic second, Take the corresponding boundary value.

[0093] Based on atmospheric pressure, gravitational acceleration, still water depth, and reactor volume, the ultimate dissipation rate is converted into the target gas flow rate.

[0094] The total turbulent mechanical power is obtained by multiplying the limiting dissipation rate, liquid phase density, and reactor volume. The reactor volume is [not specified in the original text]. The unit is cubic meters, pre-stored in the storage module, representing the effective reaction volume of the organic wastewater treatment reactor. The total mechanical power of the turbulence is measured in watts, representing the total mechanical power required to generate the desired turbulence intensity.

[0095] The hydrostatic pressure difference is obtained by multiplying the liquid density, gravitational acceleration, and still water depth. Here, gravitational acceleration... The unit is meters per second squared, pre-stored in the storage module, and is the local standard value for gravitational acceleration, with an initial value of 9.81 meters per second squared. Still water depth. The unit is meters, pre-stored in the storage module. The initial value is the vertical distance from the aerator installation position to the designed liquid level of the reactor, and is updated in real time according to the reactor liquid level. The updated data comes from the reactor liquid level sensor. The hydrostatic pressure difference value is in Pascals and represents the hydrostatic pressure difference between the aerator outlet and the liquid surface.

[0096] Divide the hydrostatic pressure difference by the atmospheric pressure and add one, then take the natural logarithm of the sum to obtain the isothermal expansion ratio. Where atmospheric pressure is... The unit is Pascal, pre-stored in the storage module, with an initial value of local standard atmospheric pressure, updated in real time by an atmospheric pressure sensor. The isothermal expansion ratio is a dimensionless parameter characterizing the degree of isothermal expansion of air from the aerator outlet to the liquid surface. When the isothermal expansion ratio is less than or equal to 0, it is taken as 10. -6 .

[0097] Multiplying the isothermal expansion ratio by atmospheric pressure yields the isothermal expansion specific work. The unit of isothermal expansion specific work is joules per cubic meter, which characterizes the work done by a unit volume of air during isothermal expansion.

[0098] Divide the total power of the turbulent machinery by the specific work of isothermal expansion to calculate the target gas flow rate. The calculation formula is:

[0099]

[0100] in, The target gas flow rate, expressed in cubic meters per second, represents the required flow rate of blower air to meet the limiting dissipation rate requirement. When less than 0, Take 0.

[0101] Calculate the time partial derivative of the target gas flow rate, combine it with the time constant to generate an overshoot, add it to the target gas flow rate, and send a compensation command to the blower.

[0102] The time partial derivative is obtained by performing ordinary differential derivative calculations on the target gas flow rate with respect to time. The unit of the time partial derivative is cubic meters per second squared, which characterizes the rate of change of the target gas flow rate with time. It is calculated using the central difference method, and the calculation method is consistent with the calculation method of the instantaneous stress decay rate.

[0103] The overshoot is calculated by multiplying the partial derivative by the time constant, and then by the overshoot gain coefficient. The overshoot is measured in cubic meters per second and is used to compensate for control lag caused by the mass transfer delay at the micro-interface and the execution delay of the aeration equipment, ensuring that the aeration flow rate can respond in advance to changes in the oxygen demand of microorganisms. The overshoot gain coefficient is also used. Dimensionless, ranging from 0.5 to 2.0, tuned according to the response time of the blower equipment, with an initial value of 1.0, tuned using the critical proportionality method, the tuning steps being to gradually increase... The value is recorded until the system exhibits constant amplitude oscillations. The critical proportional gain and critical period are then recorded, and the optimal value is calculated. value.

[0104] The target gas flow rate is added to the overshoot, and then the blower's execution delay is compensated to generate a compensation command, which is then sent to the blower. The calculation formula is:

[0105]

[0106] in, The final gas flow rate corresponding to the compensation command is expressed in cubic meters per second. Delay compensation for the blower equipment is achieved using a Smith predictor. The estimated delay time is the sum of the blower equipment's rotational speed response time and the valve actuation time, typically ranging from 2 to 5 seconds. The controller converts the compensation command into a 4 mA to 20 mA analog signal or a Modbus digital signal and sends it to the blower equipment. 4 mA corresponds to the blower's minimum flow rate, and 20 mA corresponds to the blower's maximum flow rate. The linear mapping formula is as follows: ,in This is the current value. and These represent the minimum and maximum flow rates of the blower. The Modbus protocol uses RTU mode, with register address 40001, function code 06, and data format of 16-bit unsigned integers ranging from 0 to 10000, corresponding to 0 to 100% of the rated flow rate. The control command update cycle is 100 milliseconds, the command is retransmitted 3 times, and the retransmission interval is 10 milliseconds.

[0107] When multiple blowers operate in parallel, a strategy of distributing flow based on equipment efficiency is adopted. The total flow demand is allocated to each device according to its rated efficiency ratio. If a single device fails, its flow is automatically distributed to other normally operating devices to ensure that the total flow requirement is met. Equipment start-up and shutdown employ a rotation mechanism, prioritizing the start-up of devices with shorter cumulative operating time and prioritizing the shutdown of devices with longer cumulative operating time, thus extending the equipment's service life.

[0108] During system operation, the status of all sensors and equipment is monitored in real time. If a sensor experiences data loss, exceeds its measurement range, or has 10 consecutive sampling points outside the reasonable range, it is considered a sensor malfunction. The system automatically switches to a safe mode with a fixed aeration flow rate of 50% of the rated flow rate and issues an audible and visual alarm. If the blower equipment malfunctions and cannot operate normally, the system automatically activates the backup blower equipment and issues an audible and visual alarm. During software operation, all division-by-zero errors, array out-of-bounds errors, and memory leak errors are captured. When an error occurs, a detailed fault log is recorded, including the error type, occurrence time, and relevant parameter values. The system attempts to recover calculations from the most recent valid state; if recovery fails, the system automatically restarts.

[0109] The system parameter management module supports online modification and saving of all parameters. Modified parameters automatically take effect and are stored in non-volatile memory. The system supports parameter backup and recovery functions, allowing users to export current parameter configurations to files and import parameter configurations from files. System operation logs and fault logs are stored on the local hard drive and retained for at least one year. Log content includes timestamps, module names, event types, and detailed descriptions. Logs can be queried by time range and event type.

[0110] The system monitors aerator head blockage in real time during operation. Blockage is identified by comparing the difference between the target gas flow rate and the actual output flow rate of the blower equipment. When the deviation between the actual output flow rate and the target flow rate exceeds 20% and lasts for more than 30 seconds, it is determined that the aerator head is blocked, and the system issues an audible and visual alarm and records the fault log. When the reactor level sensor detects that the liquid level is 0.1 meters below the installation height of the aerator head, the system immediately stops all blower equipment and issues an emergency shutdown alarm to prevent the blower equipment from running dry and being damaged.

[0111] The system's breakpoint resume mechanism is implemented using state snapshots. Every 10 seconds, a snapshot of all state variables is saved to non-volatile memory. The snapshot content includes all intermediate parameters and control output values ​​at the current moment. After a system restart, the most recent valid state snapshot is automatically loaded, and operation continues from that state, avoiding re-entering the data warm-up phase after a restart and reducing system downtime.

[0112] The adaptive adjustment mechanism for water quality fluctuations is based on wastewater COD concentration and pH value. When the COD concentration change exceeds 50% or the pH value exceeds the range of 6 to 9, the system automatically adjusts the mass transfer efficiency correction coefficient and the overshoot gain coefficient. The adjustment formula is as follows: , ,in and As the baseline parameter value, The system is designed to handle influent COD concentration. When the water quality fluctuates by more than 100%, the system temporarily switches to a fixed aeration flow rate mode, which lasts for 10 minutes before resuming automatic control to prevent system oscillations caused by drastic water quality fluctuations.

[0113] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. An automated parameter control system for organic wastewater treatment, comprising a high-frequency torque rheometer, a Doppler ultrasonic probe, a dissolved oxygen probe, a blower, a storage module, and a controller; wherein the storage module pre-stores liquid phase density, oxygen diffusion coefficient, saturated dissolved oxygen concentration, atmospheric pressure, gravitational acceleration, still water depth, and reactor volume; characterized in that, The controller performs: The rheological sensor is controlled to collect transient shear stress and shear strain rate, and to calculate transient apparent viscosity and stress relaxation time. The ultrasonic probe is controlled to obtain the bubble diameter and rising velocity. Combined with the liquid phase density and transient apparent viscosity, the boundary liquid film thickness is calculated. Combining the oxygen diffusion coefficient and stress relaxation time, the time constant is constructed using the boundary liquid film thickness; The dissolved oxygen probe is controlled to collect real-time dissolved oxygen concentration, and the actual oxygen consumption rate is restored by combining the saturated dissolved oxygen concentration with the time constant. Using the actual oxygen consumption rate, saturated dissolved oxygen concentration, real-time dissolved oxygen concentration, transient apparent viscosity and liquid density, the limiting dissipation rate is derived. Based on the atmospheric pressure, gravitational acceleration, still water depth, and reactor volume, the limiting dissipation rate is converted into the target gas flow rate. Calculate the time partial derivative of the target gas flow rate, combine it with the time constant to generate an overshoot, add it to the target gas flow rate, and send a compensation command to the blower.

2. The automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The calculation of transient apparent viscosity and stress relaxation time includes: The transient apparent viscosity is obtained by dividing the transient shear stress by the shear strain rate. The instantaneous stress decay rate is obtained by performing a partial derivative of the transient shear stress with respect to time. The stress relaxation time is obtained by dividing the transient shear stress by the instantaneous stress decay rate and taking the absolute value.

3. The automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The process of determining the boundary liquid film thickness includes: Multiplying the transient apparent viscosity by the bubble diameter yields the dynamic lag product; Multiplying the liquid phase density by the upward velocity yields the momentum-convection product; The boundary liquid film thickness is obtained by dividing the product of dynamic resistance by the product of momentum convection and taking the square root.

4. The automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The construction time constant includes: The squared value of the spatial barrier thickness is obtained by squaring the thickness of the boundary liquid film. Divide the squared value of the spatial barrier thickness by the oxygen diffusion coefficient to calculate the molecular penetration delay time. The time constant is constructed by adding the molecular permeation delay time to the stress relaxation time.

5. An automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The restored true oxygen consumption rate includes: The absolute value of the instantaneous time partial derivative of dissolved oxygen is obtained by calculating the partial derivative of the real-time dissolved oxygen concentration with respect to time and taking the absolute value. The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration. Dividing the concentration-driven difference by the time constant yields the implicit oxygen debt flux; The absolute value of the instantaneous time partial derivative of dissolved oxygen is added to the implicit oxygen debt flux to reconstruct the true oxygen consumption rate.

6. The automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The derivation of the limiting dissipation rate includes: The concentration-driven difference is obtained by subtracting the real-time dissolved oxygen concentration from the saturated dissolved oxygen concentration. Divide the actual oxygen consumption rate by the concentration-driven difference, and square the resulting quotient to obtain the mass transfer frequency driving term. Divide the transient apparent viscosity by the liquid phase density to obtain the momentum-viscosity drag term; The limiting dissipation rate is derived by multiplying the mass transfer frequency driving term by the momentum viscous resistance term.

7. An automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The step of converting the limiting dissipation rate into a target gas flow rate includes: Multiplying the limiting dissipation rate, the liquid phase density, and the reactor volume together yields the total turbulent mechanical power. The hydrostatic pressure difference is obtained by multiplying the liquid phase density, the gravitational acceleration, and the still water depth. Divide the hydrostatic pressure difference by the atmospheric pressure and add one, then take the natural logarithm of the sum to obtain the isothermal expansion ratio. Multiplying the isothermal expansion ratio by the atmospheric pressure yields the isothermal expansion ratio work. The target gas flow rate is calculated by dividing the total power of the turbulent machinery by the specific work of the isothermal expansion.

8. An automated parameter control system for organic wastewater treatment according to claim 1, characterized in that, The process of calculating the time partial derivative of the target gas flow rate, combining it with the time constant to generate an overshoot, adding it to the target gas flow rate, and then sending a compensation command to the blower equipment includes: The time partial derivative is obtained by performing a partial derivative calculation on the target gas flow rate with respect to time. Multiplying the time partial derivative by the time constant yields the overshoot. The target gas flow rate is added to the overshoot to generate the compensation command, which is then sent to the blower.

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