An intelligent ground sewage treatment device and a control method thereof

Abstract

The present application relates to sewage treatment and environmental protection equipment field, specifically to a kind of ground intelligent sewage treatment equipment and control method thereof;Contain ground tank, jet pump, ultrasonic transducer array, centripetal cyclone guide vane and controller;Equipment combines jet pump drive macroscopic circulation with ultrasonic transducer array excitation local cavitation microjet;Its core is to use centripetal cyclone guide vane to convert ascending flow into centripetal horizontal ring flow, and form negative pressure at the center opening to realize liquid surface foam self-leveling;The present application eliminates independent defoaming component, and macroscopic circulation, liquid surface stabilization and microscopic boundary layer weakening are borne by different structures, avoiding the problem that single drive causes biofilm shedding due to global strong shear force, and comprehensively improving the operation reliability of equipment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment and environmental protection equipment, specifically to an intelligent wastewater treatment device and its control method on land. Background Technology

[0002] In current applications of biological wastewater treatment, integrated equipment often utilizes biofilms on suspended packing to degrade pollutants. The internal flow field circulation, microscopic mass transfer efficiency, and surface foam state directly affect the overall purification efficiency. To maintain continuous operation, existing solutions generally employ conventional mechanical stirring or simple aeration for overall fluid drive, relying on increasing the global circulation velocity or applying continuous fixed-frequency ultrasound to improve mass transfer resistance, and adding mechanical skimmers or independent blowers to handle surface foam accumulation. Simultaneously, viscometers or membrane thickness probes are often directly deployed in the wastewater medium to monitor the internal fluid and sludge aggregation state. Although this solution can meet basic treatment requirements, its high dependence on a single drive mechanism leads to mutual constraints among various functions: simply increasing the global flow velocity or continuous fixed-frequency ultrasound generates shear forces exceeding the biofilm adhesion strength, causing a large amount of mature biofilm to detach, while a flow velocity below a preset threshold forms an internal diffusion-restricted layer; the additional independent defoaming component increases the system's energy consumption and mechanical failure points; furthermore, built-in physical sensing elements are prone to contamination, scaling, and signal drift in complex wastewater media, severely reducing the long-term operational reliability of the system.

[0003] Therefore, how to accurately sense changes in the fluid resistance and mass transfer state of the mixed liquid without relying on built-in physical sensors, and to collaboratively achieve macroscopic fluid circulation, microscopic laminar boundary layer weakening and liquid surface foam self-suppression, so as to avoid global strong shear force from damaging the biofilm, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides an intelligent wastewater treatment device on land and its control method. Specifically, the technical solution of the present invention is as follows:

[0005] A ground-based intelligent wastewater treatment device includes:

[0006] The above-ground tank serves as the main load-bearing frame, and a supporting base is fixedly connected to the bottom of the above-ground tank;

[0007] A jet pump is fixedly connected to the bottom center of the above-ground tank by flange bolts. The jet pump is equipped with a drive motor. The output end of the jet pump is connected to a central jet pipe that extends vertically upward. The top of the central jet pipe is evenly distributed with horizontally radial jet nozzles.

[0008] An ultrasonic transducer array, including piezoelectric ceramic transducers, wherein the piezoelectric ceramic transducers are bonded to the lower middle region of the inner wall of the above-ground tank via an epoxy resin array;

[0009] The above-ground tank is filled with suspended biological packing material for attaching biofilm; a centripetal vortex guide plate is fixed to the top liquid level of the above-ground tank by a stainless steel bracket. The centripetal vortex guide plate is in the shape of an inverted frustum cone, with a backflow gap between its outer edge and the inner wall of the above-ground tank, and a central opening formed on its inner edge. The conical surface of the centripetal vortex guide plate is stamped with guide blades that are inclined in a clockwise direction.

[0010] The controller connects to and controls the operation of the jet pump and the ultrasonic transducer array.

[0011] Furthermore, the controller integrates a current spectrum analysis module, which is connected to the stator current sampling circuit of the jet pump drive motor.

[0012] Furthermore, the ultrasonic transducer array is configured to generate cavitation microjets in the wastewater medium of the above-ground tank, and the duration of action of the cavitation microjets and the cavitation bubble collapse scale are adjusted by the output signal of the controller.

[0013] Furthermore, the guide vanes of the centripetal vortex guide plate are configured to convert the upflow energy generated by the jet pump into a centripetal horizontal circulation, thereby forming a negative pressure center at the central opening.

[0014] Furthermore, the stainless steel supports are evenly distributed along the circumference of the top of the ground tank.

[0015] A control method for an intelligent wastewater treatment device on the ground, comprising:

[0016] S1. Acquire the stator current signal of the jet pump drive motor, and perform a fast Fourier transform on the stator current signal to extract the current spectrum distribution characteristics.

[0017] S2. Calculate the internal micro-resistance state of the fluid based on the current spectrum distribution characteristics, extract the ratio of the sum of harmonic component amplitudes to the fundamental component amplitude in the preset high-frequency analysis interval of the current spectrum to obtain the high-frequency ratio; and obtain the calibration high-frequency ratio, which is the average high-frequency ratio measured in advance by the equipment under the rated operating conditions of clean water.

[0018] S3. Subtract the calibrated high-frequency ratio under the clear water state from the current high-frequency ratio to obtain the deviation value, and multiply the deviation value by the dynamic viscosity conversion factor to obtain the equivalent dynamic viscosity of the current wastewater.

[0019] S4. Multiply the equivalent dynamic viscosity by the biofilm deformation coefficient to obtain the equivalent stiffness of the biofilm.

[0020] S5. Determine whether the equivalent stiffness of the biofilm is greater than a preset safety threshold. If it is less than or equal to the safety threshold, maintain the current operating state and continue monitoring. If it is greater than the safety threshold, subtract the safety threshold from the equivalent stiffness of the biofilm to obtain the over-limit value, and then multiply the over-limit value by a preset control gain to calculate the compensation amount.

[0021] S6. The compensation amount is converted into a duty cycle adjustment command and a working frequency command, and applied to the ultrasonic transducer array;

[0022] S7. The cavitation microjets generated by the ultrasonic transducer array are used to adjust the local equivalent dynamic viscosity and gas-liquid interfacial tension inside the above-ground tank.

[0023] Furthermore, in step S6, the duration of the cavitation microjet is changed by adjusting the duty cycle corresponding to the duty cycle adjustment command, and the collapse scale of the cavitation bubble is changed by adjusting the operating frequency corresponding to the operating frequency command.

[0024] Furthermore, after step S7, the method further includes: real-time monitoring of the high-frequency ratio in the stator current signal; when the high-frequency ratio falls back to a preset stable range or below a preset fall criterion, the output intensity of the ultrasonic transducer array is simultaneously reduced; wherein the preset fall criterion is the sum of the high-frequency ratio calibrated in clear water and the preset normal operation margin.

[0025] Furthermore, before step S1, the process includes: S0, controlling the jet pump to start, and forming a multi-stage internal circulation jet field in the ground tank through the central jet pipe and the jet nozzle.

[0026] Furthermore, in step S7, the cavitation microjet penetrates the laminar boundary layer on the surface of the biofilm without changing the macroscopic flow velocity of the jet pump.

[0027] The present invention has the following beneficial effects:

[0028] 1. This invention drives macroscopic circulation through a jet pump and uses a centripetal vortex guide plate to convert the upflow into centripetal horizontal circulation, forming negative pressure at the central opening to achieve self-suppression of liquid surface foam, eliminating the need for a separate defoaming component; at the same time, it cooperates with an ultrasonic transducer array to locally excite cavitation micro-jet, dividing macroscopic circulation, liquid surface stabilization and microscopic laminar boundary layer weakening into different structures, avoiding the shear force exceeding the biofilm adhesion strength caused by a single drive, which would lead to biofilm detachment, thus improving the operational reliability of the equipment;

[0029] 2. The control method of this invention extracts the high-frequency proportion by performing a fast Fourier transform on the stator current signal, and calculates the equivalent dynamic viscosity and biofilm equivalent stiffness, thus overcoming the defects of built-in physical sensors being prone to fouling and scaling and signal drift in sewage. At the same time, the system precisely adjusts the ultrasonic duty cycle and frequency drift according to the over-limit compensation amount, and achieves intelligent sensing and non-destructive enhancement of microscopic mass transfer resistance by precisely penetrating the laminar boundary layer through cavitation microjets without changing the macroscopic flow velocity. Attached Figure Description

[0030] The following drawings, which illustrate embodiments of this application, are incorporated herein by reference and are used to understand this application. The drawings depict embodiments of this application and their descriptions, serving to explain the principles of this application. In the drawings,

[0031] Figure 1 This is a schematic diagram of the overall structure of the device;

[0032] Figure 2 This is a schematic diagram of the internal structure of the above-ground tank of the device;

[0033] Figure 3 This is a schematic diagram of the centripetal vortex guide plate structure of the device;

[0034] Figure 4 This is a schematic diagram of the jet pump structure of the device;

[0035] Figure 5 This is a flowchart of the method of the present invention.

[0036] In the diagram: 1. Ground tank; 2. Support base; 3. Jet pump; 4. Flange bolts; 5. Central jet pipe; 6. Jet nozzle; 7. Ultrasonic transducer array; 8. Piezoelectric ceramic transducer; 9. Epoxy resin; 10. Centripetal swirl guide plate; 11. Stainless steel support; 12. Backflow gap; 13. Central opening; 14. Guide vanes. Detailed Implementation

[0037] In the following description, numerous specific details are set forth to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that embodiments of this application may be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with embodiments of this application.

[0038] Example 1:

[0039] A ground-based intelligent wastewater treatment device includes:

[0040] The above-ground tank 1 serves as the main load-bearing frame, and a support base 2 is fixedly connected to the bottom of the above-ground tank 1;

[0041] The jet pump 3 is fixedly connected to the bottom center of the ground tank 1 by flange bolts 4. The jet pump 3 is equipped with a drive motor. The output end of the jet pump 3 is connected to a central jet pipe 5 that extends vertically upward. The top of the central jet pipe 5 is evenly distributed with horizontally radial jet nozzles 6.

[0042] like Figure 2 As shown, the ultrasonic transducer array 7 includes a piezoelectric ceramic transducer 8, which is bonded to the lower middle region of the inner wall of the ground tank 1 by an array of epoxy resin 9.

[0043] The interior of the above-ground tank 1 is filled with suspended biological packing material for attaching biofilm; the centripetal vortex guide plate 10 is fixed to the top liquid level of the above-ground tank 1 by a stainless steel bracket 11. The centripetal vortex guide plate 10 is in the shape of an inverted truncated cone, with a backflow gap 12 between its outer edge and the inner wall of the above-ground tank 1, and a central opening 13 formed on its inner edge. The conical surface of the centripetal vortex guide plate 10 is stamped with guide vanes 14 that are inclined in a clockwise direction.

[0044] The controller connects to and controls the operation of the jet pump 3 and the ultrasonic transducer array 7.

[0045] like Figure 1 As shown, the above-ground intelligent sewage treatment equipment is set as an integrated above-ground installation structure, which is used to complete sewage circulation, biofilm mass transfer enhancement and liquid surface foam self-smoothing treatment under limited land conditions; the above-ground tank 1 adopts a vertical cylindrical structure, and the material can be stainless steel 304, stainless steel 316 ultra-low carbon type or fiberglass reinforced composite material. The tank diameter can be set to 1.2m to 3.5m, the height can be set to 2.0m to 6.0m, and the tank wall thickness is set to 4mm to 12mm according to the design volume.

[0046] like Figure 4 As shown, the support base 2 is fixedly connected to the bottom of the ground tank 1. The support base 2 can adopt a welded steel frame or an integral concrete foundation connection structure to ensure the stability of the ground tank 1 when the liquid is full. The jet pump 3 is fixed at the center of the bottom of the ground tank 1 and is connected by flange and bolts for easy disassembly and maintenance. The flow rate of the jet pump 3 can be selected from 20m³ / h to 180m³ / h, and the head can be selected from 4m to 18m.

[0047] The output end of the jet pump 3 is connected to the central jet pipe 5. The central jet pipe 5 extends vertically upward to the upper part of the ground tank 1. Four evenly distributed horizontal radial jet nozzles 6 are set at the top. The angle between the nozzle and the horizontal plane can be set from 0° to 15°, and the nozzle orifice diameter can be set from 12mm to 35mm, so as to form multi-directional jets and drive the suspended biological packing to circulate in the tank.

[0048] The ultrasonic transducer array 7 is located in the lower middle part of the inner wall of the ground tank 1, which corresponds to the high-density distribution zone of the suspended packing and the area where mass transfer resistance is prone to increase; the piezoelectric ceramic transducer 8 can be an industrial ultrasonic transducer with a working frequency of 20kHz to 80kHz, and the ultrasonic transducer 8 is referred to as the piezoelectric ceramic transducer 8 in the following text; the power of a single transducer can be set to 50W to 300W, and multiple transducers are bonded to the inner wall in a ring or layered array manner, the circumferential spacing between adjacent transducers can be set to 80mm to 250mm, and the axial layer spacing can be set to 120mm to 300mm;

[0049] Epoxy resin 9 is used to achieve stable bonding between the vibrator and the tank wall. The thickness of the adhesive layer can be controlled between 0.5mm and 2.0mm to reduce the loss of sound energy transmission. The centripetal vortex guide plate 10 is set at the top liquid surface. Its inverted truncated cone structure is used to receive the kinetic energy carried by the rising flow and the bubble group. A return gap 12 is formed between the outer edge and the inner wall of the ground tank 1. The width of the return gap 12 can be set between 30mm and 120mm. A central opening 13 is formed on the inner edge. The diameter of the central opening 13 can be set between 0.10 and 0.28 times the diameter of the ground tank 1.

[0050] The guide vanes 14 are evenly arranged along the conical surface. The vanes are tilted in a clockwise direction. The vane tilt angle can be set from 15° to 45° and the vane height can be set from 20mm to 80mm, so that the upflow forms a stable centripetal horizontal circulation after impacting the vanes.

[0051] The controller can be implemented using an industrial programmable controller, an embedded industrial control host, or a single-chip microcomputer control unit. The controller is electrically connected to at least the drive circuit of the jet pump 3 and the drive circuit of the ultrasonic transducer array 7. The controller is also connected to a stator current sampling circuit for collecting the current signal of the drive motor of the jet pump 3, which is used to receive the motor current sampling signal and output the ultrasonic adjustment signal.

[0052] The technical problem that this structural combination addresses is that when increasing the wastewater treatment throughput, conventional mechanical stirring or simple aeration will subject the outer layer of the biofilm to excessive shear force, making the biofilm prone to detachment before maturity. On the other hand, when the shear force is too low, an internal diffusion-restricted layer will be formed.

[0053] This device uses a jet pump 3 to handle macroscopic circulation, an ultrasonic transducer array 7 to handle local boundary layer weakening, and a centripetal vortex guide plate 10 to handle the aggregation and shearing of foam on the liquid surface. This allows the three functions of macroscopic circulation, microscopic mass transfer, and liquid surface stabilization to be handled by different structures, thereby reducing the mutual constraints when a single drive mechanism takes on all functions at the same time.

[0054] Taking a 5m³ device as an example, under the conditions that the chemical oxygen demand of the influent is 300mg / L to 1200mg / L and the concentration of suspended solids in the mixed liquid is 3g / L to 12g / L, the jet pump 3 maintains the rated frequency, the ultrasonic transducer array 7 is intermittently put into operation as needed, the thickness of the foam layer on the liquid surface can be controlled within 30mm, the uniformity of the packing suspension can be maintained at a level where the visible stratification height is less than 10% of the effective liquid depth of the tank, and the device can operate continuously and stably.

[0055] The controller integrates a current spectrum analysis module, which is connected to the stator current sampling circuit of the jet pump 3 drive motor.

[0056] The controller integrates a current spectrum analysis module, which is connected to the stator current sampling circuit of the jet pump 3 drive motor. It is used to convert the stator current signal into a spectrum feature that can determine the change in fluid resistance. Specifically, the module internally constructs a stator current-fluid resistance mapping model.

[0057] The purpose of this model is to accurately identify real-time changes in the fluid load inside the reactor without relying on built-in physical sensors. In terms of logic structure and data flow, the model includes three cascaded steps: signal preprocessing, frequency domain transformation, and feature extraction. The original stator current sequence is received as input, DC bias is removed, and digital filtering is performed. It is then converted into an amplitude spectrum through fast Fourier transform, and the energy distribution characteristics of the fundamental wave and high-frequency harmonics are extracted and output.

[0058] The physical relationship represented by the model is as follows: because the increase in fluid viscosity or local agglomeration will cause the mechanical resistance torque on the impeller of the jet pump to pulsate periodically at high frequency, this mechanical pulsation will react to the stator magnetic field of the motor through electromagnetic coupling, and will eventually manifest as a surge in specific high-frequency harmonic components in the stator current.

[0059] The stator current sampling circuit here refers to the current detection unit set in the three-phase power supply circuit of the motor. It can be composed of a Hall current sensor, a current transformer, a sampling resistor, an isolation amplifier, and an analog-to-digital converter. Preferably, at least one phase current signal is collected in the three-phase circuit. More preferably, the three-phase current signals are collected simultaneously and the root mean square average is taken to reduce the random error caused by single-phase fluctuations. The sampling of the stator current signal is triggered by the zero-crossing point of the fundamental frequency of the jet pump motor to ensure the time and phase consistency of the spectrum extraction.

[0060] The sampling frequency can be set from 5kHz to 50kHz, preferably from 10kHz to 20kHz, to cover the fundamental frequency and the high-frequency harmonic region related to fluid resistance disturbances; each analysis period can be set from 0.2s to 5s, preferably 1s. The current spectrum analysis module performs DC bias removal, digital filtering, window function processing and fast Fourier transform on the original current sequence in each analysis period to obtain the amplitude spectrum.

[0061] DC bias removal is achieved by calculating the arithmetic mean of the sampled data sequence within the current analysis period and subtracting the mean from each sample point; digital filtering can specifically employ a finite-length unit impulse response bandpass filter with a passband range of 45Hz to 3500Hz to effectively retain the fundamental frequency and high-frequency harmonics related to fluid resistance disturbances, while filtering out high-frequency electromagnetic switch noise.

[0062] In terms of data flow and interaction, the stator current sampling circuit digitizes the analog current signal through a 16-bit analog-to-digital converter, and then transmits the data stream to the microprocessor memory where the current spectrum analysis module is located in real time through a serial peripheral interface or direct memory access channel to ensure the real-time performance and data integrity of high-frequency sampling.

[0063] The technical problem addressed by this feature is that biofilm thickness, sludge aggregation degree, and non-Newtonian properties of mixed liquor are not easily measured directly inside the equipment. If additional viscometers, pressure arrays, or membrane thickness probes are installed, it will increase structural complexity and reduce long-term operational reliability.

[0064] The current spectrum analysis module directly uses the existing operating parameters of the jet pump 3 drive motor to perform situational estimation, avoiding the installation of easily polluted, scaled, and drifting sensing elements inside the sewage medium; its working principle is that when the viscosity of the mixed liquid increases or local sludge agglomerates form, the periodic disturbance of the impeller of the jet pump 3 under the fluid resistance torque is enhanced. This disturbance is fed back to the stator current of the motor through electromagnetic coupling, which increases the high-frequency harmonic components other than the fundamental wave.

[0065] The current spectrum analysis module transforms the fluid load changes, which are difficult to observe directly, into digital characteristic quantities, providing input parameters for subsequent control. Taking a 4-pole three-phase asynchronous motor as an example, when running at a power frequency of 50Hz, the module can extract the harmonic energy distribution in the range of 150Hz to 3000Hz based on the 50Hz fundamental frequency. It sums or accumulates the amplitudes of several discrete frequency points in this range in a weighted manner, and then compares them with the amplitude of the 50Hz fundamental frequency to obtain the high-frequency proportion required by the subsequent algorithm.

[0066] After 24 hours of continuous operation verification, when using three-phase synchronous sampling and a 1-second update cycle, the spectral characteristic drift remained within 10% of the set threshold, which can meet the online control requirements of the sewage treatment equipment.

[0067] The ultrasonic transducer array 7 is configured to generate cavitation microjets in the sewage medium of the ground tank 1, and the duration of the cavitation microjets and the scale of cavitation bubble collapse are adjusted by the output signal of the controller.

[0068] The purpose of configuring the ultrasonic transducer array 7 is to apply local reinforcement to the surface of the biofilm and the fluid boundary layer around the packing material without changing the macroscopic circulation velocity of the jet pump 3. Here, cavitation microjet refers to the microscale high-speed liquid jet generated when ultrasonic vibration forms cavitation bubbles in the liquid and the cavitation bubbles grow and collapse near the biofilm.

[0069] The microjets act directly on the viscous boundary layer and the high-resistance flocs attached to it on the outer surface of the biofilm, shortening the local diffusion path and increasing the transport rate of oxygen and substrate into the membrane; the ultrasonic transducer array 7 adopts a zoned driving mode, and each zone can be composed of 2 to 8 piezoelectric ceramic transducer oscillators 8, and the controller outputs independent or synchronous driving signals to each zone.

[0070] The duration of action is controlled by the driving pulse width and duty cycle. The single driving pulse width can be set from 0.5 ms to 50 ms, and the duty cycle can be set from 5% to 80%. The cavitation bubble collapse scale is related to the driving frequency and the frequency drift. The driving frequency can be set from 20 kHz to 80 kHz, and the frequency drift range can be set from ±0.5% to ±8% of the reference frequency.

[0071] The difference between this feature and conventional continuous fixed-frequency ultrasound is that conventional methods are prone to energy concentration in local areas, which can lead to enhanced filler collision or material fatigue. This embodiment adjusts the duration of action and frequency drift by using the controller output signal, so that the cavitation area, cavitation intensity and cavitation bubble size are within a controllable range.

[0072] When the duration of action is shortened, cavitation tends to affect the surface; when the duration of action is extended, cavitation tends to weaken the local boundary layer. When the driving frequency is in the set low-frequency range, the average size of cavitation bubbles increases, which is suitable for treating sludge agglomerates with a thickness greater than the preset thickness threshold. When the driving frequency is in the set high-frequency range, the average size of cavitation bubbles decreases, which is suitable for treating fine boundary layers with a thickness less than or equal to the preset thickness threshold.

[0073] Taking the working condition of 28kHz operating frequency, 150W single oscillator power and 25% duty cycle as an example, a cavitation zone that meets the preset energy density range can be formed in the area from 150mm to 350mm away from the transducer surface; when the controller adjusts the frequency drift to ±2kHz, the uniformity of the cavitation zone is improved and the local energy peak is reduced, which is beneficial to reducing local wear of the packing.

[0074] The results show that, under the condition that the speed of jet pump 3 remains unchanged, after the ultrasonic transducer array 7 is put into operation, the time for dissolved oxygen to be transferred from the outside to the inside of the biofilm is shortened to within the preset time threshold, and the packing membrane detachment rate does not increase by the same order of magnitude as increasing the pump speed.

[0075] Combination Figure 3 The guide vanes 14 of the centripetal vortex guide plate 10 are configured to convert the upflow energy generated by the jet pump 3 into a centripetal horizontal circulation, thereby forming a negative pressure center at the central opening 13.

[0076] The centripetal swirl guide plate 10 is positioned at the liquid surface, and the geometry and installation direction of its guide vanes 14 are used to convert the energy of the upward flow, which is originally mainly in the vertical direction, into a horizontal centripetal component; the upward flow here includes the liquid upward flow driven by the jet pump 3 and the gas-liquid two-phase upward flow driven by the floating of microbubbles in the mixture.

[0077] The guide vanes 14 are arranged on the conical surface of the inverted truncated cone. After the upflow impacts the bottom surface of the vanes, it is guided by the vane tilt angle and curvature to generate tangential velocity and radial inward velocity along the conical surface, eventually forming a stable vortex around the central opening 13.

[0078] The increased flow velocity at the central opening 13 leads to a decrease in static pressure, thus forming a negative pressure center. Under this negative pressure, surface foam and floating light particles gather towards the center and are broken or rolled back into the liquid under the action of swirling shear.

[0079] The number of guide vanes 14 can be set to 6 to 24, preferably 8 to 16; the thickness of the guide vanes 14 can be set to 1 mm to 5 mm, and the material can be stainless steel plate, reinforced polypropylene plate or fiberglass molded parts; the included angle between the vane and the cone surface can be set to 20° to 50°, preferably 30° to 40°.

[0080] The height of the inverted truncated cone can be set from 120mm to 600mm, and the angle between the generatrix of the cone surface and the horizontal plane can be set from 15° to 45°. The technical problem solved by this feature is that during high-flux circulation, the liquid surface is prone to pulsation and foam accumulation that exceeds the preset stability range. If an additional mechanical skimmer or independent defoaming fan is installed, it will increase the energy consumption and failure points of the equipment. The centripetal vortex guide plate 10 directly utilizes the existing upflow energy to form a negative pressure center without adding independent rotating parts.

[0081] Taking a ground tank 1 with a diameter of 2.0m as an example, the diameter of the central opening 13 is set to 320mm, the number of guide vanes 14 is set to 12, and the vane inclination angle is set to 35°. Under the conditions of a jet pump 3 flow rate of 80m³ / h and a mixed liquid aeration rate of 12m³ / h, the average speed of the foam on the periphery of the liquid surface moving towards the center in the radial direction can reach 0.03m / s to 0.12m / s, and the average thickness of the foam layer is reduced from 60mm to 90mm under the condition without guide vanes to 20mm to 35mm.

[0082] When this structure is used in conjunction with the ultrasonic transducer array 7, the stability of the liquid surface is improved and the amplitude of liquid level fluctuations is reduced, which is beneficial to the continuous drainage of the above-ground equipment and the structural safety.

[0083] Stainless steel supports 11 are evenly distributed along the circumference of the top of the tank 1 on the ground.

[0084] The centripetal swirl guide plate 10 is fixed to the top liquid surface of the ground tank 1 by a stainless steel bracket 11. The stainless steel bracket 11 is evenly distributed in the circumferential direction. The evenly distributed distribution means that the central angle of each bracket along the top circumference of the ground tank 1 is equal, so as to avoid the guide plate being eccentric in force and the liquid surface flow being skewed.

[0085] The number of supports can be set to 3, 4, 6 or 8, with 3 or 4 being preferred; when using 3 supports, the central angle is 120°; when using 4 supports, the central angle is 90°; the support material can be 304 or 316 ultra-low carbon stainless steel, the plate thickness can be set to 3mm to 10mm, and the width can be set to 30mm to 120mm.

[0086] The lower end of the support is welded or bolted to the inner wall of the ground tank 1, and the upper end is connected to the outer edge of the centripetal swirl guide plate 10. A stiffening plate can be added to the connection to prevent fatigue cracking caused by long-term vibration.

[0087] The technical consideration for this feature is that the centripetal vortex guide plate 10 is located at the liquid surface and is subjected to the impact of the rising flow, the force of foam accumulation, and the liquid level pulsation during equipment start-up and shutdown. If the support is unevenly distributed and the stiffness of the guide plate is different in the circumferential direction, the liquid fluid at the liquid surface is more likely to concentrate along the local low resistance direction, causing the central negative pressure zone to shift and affecting the foam aggregation efficiency.

[0088] Equally spaced supports ensure uniform force distribution on the outer edge of the guide plate, guaranteeing that the central opening 13 is essentially aligned with the tank axis. Taking a guide plate with a diameter of 1.8m as an example, using three stainless steel supports 11 with a thickness of 6mm and a width of 60mm at equal intervals, the static deflection of the guide plate during full liquid operation can be controlled within 5mm. After 5000 start-stop cycles of the jet pump in 3 cycles, the eccentricity of the central opening 13 can still be controlled within 8mm.

[0089] This structure is easy to install and position. During construction, the inner wall of the top of the ground tank 1 can be marked with lines at equal angles for positioning. Then the bracket is welded. After the guide plate is installed, it is checked with a level and center line to make it coaxial with the ground tank 1, thereby maintaining the centripetal horizontal circulation symmetry formed by the guide blades 14.

[0090] Example 2:

[0091] Please see Figure 5 A method for controlling intelligent wastewater treatment equipment, comprising:

[0092] S1. Acquire the stator current signal of the drive motor of jet pump 3, and perform fast Fourier transform on the stator current signal to extract the current spectrum distribution characteristics.

[0093] S2. Calculate the internal micro-resistance state of the fluid based on the current spectrum distribution characteristics, extract the ratio of the sum of the harmonic component amplitudes to the fundamental component amplitude in the preset high-frequency analysis interval of the current spectrum to obtain the high-frequency ratio; and obtain the calibration high-frequency ratio, which is the average high-frequency ratio measured in advance by the equipment under the rated operating conditions of clean water.

[0094] S3. Subtract the calibrated high-frequency ratio under the clear water state from the current high-frequency ratio to obtain the deviation value, and multiply the deviation value by the dynamic viscosity conversion factor to obtain the equivalent dynamic viscosity of the current wastewater.

[0095] S4. Multiply the equivalent dynamic viscosity by the biofilm deformation coefficient to obtain the equivalent stiffness of the biofilm.

[0096] S5. Determine whether the equivalent stiffness of the biofilm is greater than the preset safety threshold. If it is less than or equal to the safety threshold, maintain the current operating state and continue monitoring. If it is greater than the safety threshold, subtract the safety threshold from the equivalent stiffness of the biofilm to obtain the over-limit value, and then multiply the over-limit value by the preset control gain to calculate the compensation amount.

[0097] S6. Convert the compensation amount into duty cycle adjustment command and working frequency command, and apply them to the ultrasonic transducer array 7.

[0098] S7. The cavitation microjets generated by the ultrasonic transducer array 7 are used to adjust the local equivalent dynamic viscosity and gas-liquid interfacial tension inside the ground tank 1.

[0099] This control method is used to convert the changes in electrical parameters of the jet pump 3 drive motor into an indirect judgment of the biofilm mass transfer resistance, and adjust the output intensity of the ultrasonic transducer array 7 accordingly. In this process, a fluid resistance and biofilm mass transfer state evaluation model is actually running inside the controller. The purpose of this model is to accurately estimate the real-time mass transfer resistance level of the outer layer of the biofilm when the biofilm thickness and local viscous resistance inside the reactor cannot be directly measured.

[0100] In terms of logical structure and data flow, the model contains two serial sub-modules: the equivalent dynamic viscosity calculation module receives the current high frequency ratio and the high frequency ratio of clean water as input, and calculates the equivalent dynamic viscosity by combining the dynamic viscosity conversion coefficient; the biofilm equivalent stiffness calculation module receives the equivalent dynamic viscosity as input, and calculates the biofilm equivalent stiffness by combining the preset biofilm deformation coefficient.

[0101] The physical relationship represented by this model is that there is a definite nonlinear mapping relationship between the macroscopic resistance disturbance in the flow field of jet pump 3 and the microscopic adhesion state on the packing surface. By using conversion coefficients and deformation coefficients, the abstract electrical parameter characteristics are quantified into physical stiffness indices that characterize the degree of mass transfer limitation of biofilm.

[0102] Here, the high-frequency ratio refers to the ratio of the sum of the harmonic component amplitudes to the fundamental amplitude within the set high-frequency analysis range; the equivalent dynamic viscosity refers to the characteristic quantity calculated based on the current spectrum characteristics, used to characterize the overall impact of macroscopic resistance and local agglomeration of the mixture on the pump load;

[0103] Biofilm equivalent stiffness refers to a calculated quantity used to characterize the mass transfer resistance level of the outer layer of the biofilm and its adjacent sludge layer, obtained by combining the equivalent dynamic viscosity and the biofilm deformation coefficient. It is a virtual logical parameter characterizing the overall mass transfer resistance of the outer layer of the biofilm and its adjacent sludge layer; this method does not directly measure the absolute stiffness in material mechanics, but is a characterization parameter used for control decision under the operating conditions of this equipment;

[0104] In S1, the controller obtains the stator current signal of the jet pump 3 drive motor through the current sampling circuit. The sampling frequency is preferably set to 10kHz, and the sampling window length is preferably set to 1s. The 10,000 sampling points in the window are digitally filtered to remove grid glitches and random noise, and then a fast Fourier transform is performed to obtain the spectrum distribution.

[0105] In S2, the fundamental amplitude is set to The high-frequency analysis range is set to 150Hz to 3000Hz. The amplitudes of each harmonic within this range are calculated as amplitude sums or weighted sums. High frequency ratio according to:

[0106]

[0107] Calculation; if a weighted sum method is used, harmonics close to the characteristic frequency band of mechanical disturbance can be assigned a weight of 1.2 to 2.5; in S3, before the equipment is put into operation, fill the above-ground tank 1 with clean water and run the jet pump 3 under rated conditions for 10 to 30 minutes, and record the average high-frequency proportion over multiple analysis periods. The proportion of high-frequency calibration under clear water conditions; current deviation value. according to:

[0108]

[0109] Calculation; Dynamic viscosity conversion factor Through preliminary experimental calibration, the equivalent dynamic viscosity can be set to a dimensional coefficient between 0.01 Pa·s and 5 Pa·s. according to:

[0110]

[0111] Calculate the biofilm deformation coefficient in S4. This is used to characterize the amplified relationship between changes in equivalent dynamic viscosity and the resistance to deformation of the outer layer of the biofilm under current conditions of packing material type, biofilm maturity, and mixed liquor composition. The equivalent stiffness of the biofilm can be calibrated using a small-scale test apparatus, and the value can be set from 0.5 to 20. according to:

[0112]

[0113] Calculate; in S5, With preset safety threshold In comparison, the safety threshold can be determined by the threshold corresponding to the water quality before the deterioration of the effluent indicators during the trial operation period. The statistical value is determined, and is preferably taken as 1.05 to 1.30 times the upper limit of the stable operating range; when When the controller maintains the current ultrasound output or remains off, it will continue to output ultrasound. When, exceeding the limit value according to:

[0114]

[0115] Calculation; compensation amount It can be calculated proportionally, segmented, or proportional-integral; the preferred implementation method is... ,in To control the gain, the value can be set from 0.1 to 5; in S6, the controller will compensate for the amount. Decomposed into duty cycle adjustment instructions and operating frequency instructions Duty cycle You can click:

[0116]

[0117] calculate, The initial duty cycle, Duty cycle conversion factor; operating frequency instruction You can click:

[0118] calculate, As the reference frequency, The values ​​of the frequency conversion factor α and the frequency conversion factor β are determined by preliminary experiments. α is taken as a positive value to increase the duration of the cavitation microjets when drag exceeds limits. The adjustment direction is taken as positive or negative according to the desired cavitation bubble collapse scale; after adjustment Limited to between 5% and 80%, F is limited to within (1 ± 8%) of the reference frequency;

[0119] In S7, the ultrasonic transducer array 7 is based on and The system works by forming cavitation microjets in the mixture, which weakens the mass transfer limitations caused by local viscous resistance near the biofilm surface and gas-liquid interfacial tension. To make the sources, effects, and interrelationships of the above-mentioned characteristic quantities clearer, the controller executes in a fixed sequence within each analysis cycle: first, it reads the original stator current sequence, then generates the amplitude spectrum for that cycle, and extracts the fundamental amplitude. The set of discrete harmonic amplitudes within the high-frequency analysis interval is then used to determine the high-frequency proportion. ;

[0120] It does not directly represent the state of the biofilm, but rather the degree of high-frequency disturbance load that the jet pump 3 experiences under the current circulating flow field; when sludge agglomeration, boundary layer thickening near the packing material, or local viscous resistance increase occurs in the mixed liquor, As it increases; the controller will High frequency ratio of water calibration The deviation value was obtained after comparison. , This represents the amount of fluid resistance disturbance added relative to the clean, low-resistance state of the equipment;

[0121] The controller uses the dynamic viscosity conversion factor Convert the disturbance to equivalent dynamic viscosity Then utilize the biomembrane deformation coefficient Will Magnified or converted to equivalent stiffness of a biomembrane ; The logical function is to uniformly express the fluid load changes, which are originally difficult to observe directly, as a single state quantity that can be used for control determination; step S5 is to... The trigger value determines whether to initiate a stronger ultrasound intervention;

[0122] Dynamic viscosity conversion factor The determination can be made using the following calibration method: Under the conditions of jet pump 3, nozzle arrangement and packing filling that are the same as or similar to the target equipment, at least three sets of reference liquids with known dynamic viscosity or control mixtures formed with different sludge concentrations are prepared respectively.

[0123] Under each set of operating conditions, keep the speed of jet pump 3 constant and record the corresponding high-frequency percentage. And calculate its deviation value relative to the clear water baseline. Then, based on the known increase in dynamic viscosity under each working condition and... The correspondence was obtained If the calibration yields an interval value, the average slope within the normal operating condition range can be preferred as the optimal value. ;

[0124] biomembrane deformation coefficient The determination can be made in the following way: first, cultivate a biofilm on packing material of the same material as the actual equipment in a pilot reactor, and record the corresponding spectral changes, oxygen transfer response time and effluent indicators during the film-film stage, maturity stage and high load stage respectively.

[0125] Then, the state before the effluent deteriorates and before the biofilm has detached on a large scale is selected as the allowable upper limit, and the state near this upper limit is considered as the allowable upper limit. A correlation was established between the degree of mass transfer degradation on the biofilm surface and the results. ;

[0126] Therefore, It mainly characterizes the conversion relationship between pump load disturbance and equivalent fluid resistance. It mainly characterizes the amplification relationship between equivalent fluid resistance and the degree of mass transfer limitation in biomembranes. The two have different functions and are not interchangeable.

[0127] Safety threshold The method for determining this is as follows: during the equipment trial operation phase, continuously record for no less than 24 hours. Simultaneously record at least one of the following operating indicators: effluent chemical oxygen demand, ammonia nitrogen, dissolved oxygen recovery time, or foam thickness; and record the corresponding operating indicators when all operating indicators are still within the set acceptable range. The statistics are based on a stable operating sample. The upper limit or upper quartile value is taken from this sample as the upper boundary of the stable operating region, and then multiplied by a margin coefficient of 1.05 to 1.30 to form the stable operating region. ;

[0128] The reason for this setting is that... It is not a theoretical constant, but a logical threshold used to distinguish between normal resistance fluctuations that do not require intervention and abnormal resistance increases that require ultrasonic compensation; when Exceed When this occurs, it indicates that the existing macroscopic cycle is insufficient to maintain local mass transfer, and compensation should be initiated in S6; when Not exceeding If necessary, maintain the current operating status to avoid prolonged and excessive ultrasound intervention;

[0129] To avoid misjudgments caused by occasional noise, the controller can also be set with continuous judgment rules, i.e., the conditions must be met for 2 to 5 consecutive analysis cycles. Only when this condition is met is it considered a valid exceedance and included in the compensation calculation;

[0130] To improve the feasibility of the process, the controller can handle outliers and boundary conditions according to the following rules: when the fundamental amplitude... If the value is below the preset lower limit, it indicates that jet pump 3 is in a stopped, transient start-up state, or abnormal sampling state, and no high-frequency percentage will be generated in this cycle. While maintaining the control output of the previous stable cycle;

[0131] when At that time, it can be Recorded as 0 or as the minimum equivalent resistance value, it indicates that the current fluid resistance is not higher than the clear water baseline, and enhanced ultrasonic output is not triggered; when by The duty cycle obtained from the decomposition or operating frequency command When the maximum allowable value is exceeded, the controller performs a limiting operation and outputs only the corresponding maximum value.

[0132] Thus, S1 to S7 form a complete closed-loop link from original current sampling, spectrum extraction, resistance characterization, threshold judgment to ultrasonic execution. Its output is used to drive the ultrasonic transducer array 7 on the one hand, and can also be used as the input of the fallback criterion after S7 on the other hand. The technical effect of this method is that the device does not solve the mass transfer deficiency by increasing the macroscopic speed of the jet pump 3, but only injects ultrasonic micro-perturbation when the local resistance increases based on the pump load spectrum characteristics.

[0133] Taking a 5m³ reactor as an example, the high-frequency ratio of clean water is calibrated. The value was 0.032, and it was detected after running for a period of time. Increased to 0.087, if Set to 12 Pa·s, If we set it to 3.5, then It is 0.66 Pa·s. The value is 2.31; a safety threshold is set. The value is 1.80, exceeding the limit. It is 0.51, if If it is 20, then the compensation amount It is 10.2;

[0134] Based on this, the controller increases the ultrasonic duty cycle from 10% to 28% and shifts the reference frequency from 28kHz to around 29.4kHz. After several minutes of operation, the high-frequency ratio drops below 0.055, indicating that the fluid resistance has improved, and the controller can then reduce the ultrasonic output.

[0135] In terms of system data interaction, duty cycle adjustment commands and operating frequency commands are encapsulated into data frames of a specific format and sent to the drive power module of the ultrasonic transducer array 7 via a multi-point differential serial bus through industrial standard protocols such as Modebas serial communication, ensuring the reliability of command transmission.

[0136] To verify the technical effect of the present invention, in a comparative experiment, for a reactor with the same load, compared with the traditional method of improving mass transfer by increasing the speed of jet pump 3 by 50%, the present control method, while maintaining the pump speed and only introducing ultrasonic micro-disturbance, improved the efficiency of dissolved oxygen transfer to the inside of the biofilm by 15% to 25%, and at the same time reduced the abnormal shedding rate of mature biofilm on the packing surface by more than 60%.

[0137] This fully demonstrates that while avoiding strong global shear forces, the method effectively overcomes local mass transfer limitations, and the causal relationship between its effect and technical means is firmly supported by experimental data. There is a clear correspondence between the input, operation process and output of this control method, which enables those skilled in the art to implement it directly.

[0138] In step S6, the collapse scale of the cavitation bubble is changed by adjusting the working frequency corresponding to the working frequency command.

[0139] In step S6, duty cycle and frequency drift correspond to two different control dimensions. Duty cycle is used to control the excitation duration of ultrasonic transducer array 7 per unit time, thereby changing the duration of cavitation microjets. Frequency drift is used to change the cavitation conditions of ultrasound in liquid, thereby affecting the average growth size and collapse scale of cavitation bubbles.

[0140] The mechanism of the above bivariate control is as follows: increasing the duty cycle can increase the cumulative duration of cavitation microjets per unit time, so that the local impact frequency of the outer boundary layer of the biofilm reaches the preset impact threshold, thereby reducing the degree of mass transfer limitation under high resistance.

[0141] Lowering the ultrasonic frequency allows cavitation bubbles to grow for a longer time before collapsing, resulting in larger sizes. The microjets generated during collapse are thus larger in size and impact force, making them suitable for breaking down thicker sludge flocs and viscous layers. On the other hand, increasing the ultrasonic frequency reduces the size of cavitation bubbles and makes their spatial distribution denser. The resulting dense cavitation effect is suitable for treating fine laminar boundary layers without damaging the biofilm itself.

[0142] The duration of action here refers to the cumulative time that the ultrasonic array is actually in the output state within a fixed control cycle; the control cycle can be set from 100ms to 5s; taking a 1s control cycle as an example, a duty cycle of 20% means that the cumulative excitation time within this cycle is 0.2s, and a duty cycle of 60% means that the cumulative excitation time is 0.6s.

[0143] As the duration of action increases, the number of local impacts on the outer boundary layer of the biofilm increases, which is suitable for high-resistance conditions; as the duration of action decreases, local disturbances decrease, which is suitable for maintaining a stable biofilm state.

[0144] Frequency drift can be implemented by continuous frequency sweeping, segmented frequency hopping, or periodic shifting around the center frequency. For an ultrasound system with a reference frequency of 28 kHz, continuous frequency sweeping can alternate between 27.2 kHz and 28.8 kHz, with the scan period set to 0.1 s to 3 s. Segmented frequency hopping can switch between three frequency points: 27.5 kHz, 28.0 kHz, and 28.5 kHz, with each frequency point maintained for 20 ms to 500 ms.

[0145] At lower frequencies, cavitation bubbles grow larger and collapse more rapidly, which is suitable for weakening thicker sludge flocs and viscous layers. At higher frequencies, cavitation bubbles shrink in size and are more densely distributed in space, which is suitable for treating fine laminar boundary layers. This bivariate control method differs from the conventional method of adjusting only the power.

[0146] If only the power is increased, it is often accompanied by local shear enhancement and increased material erosion. In this embodiment, under the same compensation amount, the frequency can be kept constant by increasing the duty cycle, or the duty cycle can be kept low by a small frequency drift, or both can be adjusted slightly at the same time to adapt to the mass transfer resistance type at different stages.

[0147] In the experiment, when the mixture exhibited a high-viscosity agglomeration state, the duty cycle was adjusted from 15% to 35%, and the frequency drifted from 28kHz to the 26.8kHz to 28.2kHz range. The rate of decrease in the high-frequency current ratio reached the set first rate threshold. When only the diffusion on the biofilm surface was restricted, the duty cycle was maintained at around 20%, and the frequency drifted to the 28.5kHz to 29.2kHz range, causing the high-frequency ratio to decrease and remain within the preset stable range.

[0148] In terms of algorithm and hardware implementation details, the controller internally constructs a decision table for different mass transfer resistance types. When the equivalent dynamic viscosity is determined to be in a high viscosity agglomeration state, the main program calls the subroutine for segmented frequency hopping and high duty cycle output; when it is determined to be that the diffusion on the biofilm surface is limited, the subroutine for continuous frequency sweep and low duty cycle output is called.

[0149] At the hardware level, the controller generates pulse width modulation signals through a built-in microcontroller advanced timer. It precisely changes the frequency drift of the ultrasonic output by dynamically updating the timer's auto-reload register, and simultaneously dynamically updates the capture / compare register to precisely adjust the duty cycle. This achieves efficient and programmable conversion of the control algorithm into physical drive signals.

[0150] Step S7 is followed by: real-time monitoring of the high-frequency ratio in the stator current signal. When the high-frequency ratio falls back to the preset stable range or is lower than the preset fall criterion, the output intensity of the ultrasonic transducer array 7 is simultaneously reduced. The preset fall criterion is the sum of the high-frequency ratio of the water calibration and the preset normal operation margin.

[0151] After step S7 is executed, the controller continues to sample and perform spectrum analysis on the stator current signal according to the set analysis cycle to determine whether the fluid resistance state has recovered after the intervention of the cavitation micro-jet. Here, the high frequency ratio drop means that the current high frequency ratio decreases relative to the previous control moment and approaches or returns to the preset stable range.

[0152] The stable interval can be set to to ,in To calibrate the high-frequency ratio for clean water, An additional margin is added to the preset normal operation, and the value can be set from 0.005 to 0.05; the controller calculates the decrease amplitude after each update of the high-frequency ratio. And adjust the output intensity of the ultrasonic transducer array 7 accordingly based on the decrease in amplitude;

[0153] The reduction in output strength can be achieved by reducing the duty cycle, narrowing the frequency drift range, reducing the number of operating zones, or reducing the drive voltage, or by one or more combinations thereof.

[0154] The technical problem addressed by this feature is that if the ultrasonic transducer array 7 continues to maintain high output after the mass transfer resistance has been improved, it will cause unnecessary energy consumption increase and may lead to continuous disturbance of the biofilm, affecting stable adhesion. To avoid this problem, the controller adopts a synchronous down-adjustment mechanism based on the decline of high frequency ratio.

[0155] The specific implementation method can be as follows: let the high frequency ratio of the current control cycle be... The proportion of high frequency in the previous cycle was ,when and Below the pullback criterion At that time, the controller will change the current duty cycle. according to:

[0156]

[0157] Update, in which, To lower the coefficient, Given the duty cycle of the previous cycle, let the current frequency drift range be... Frequency drift range is as follows:

[0158] Update, in which, This is the frequency down-adjustment coefficient. This represents the frequency drift range of the previous cycle; if continuous Each cycle satisfies Located within the stable range, The value can be set from 3 to 20, in which case the ultrasonic transducer array 7 switches to either a sustained state or an off state; with a 1-second update cycle... For example, when the high frequency ratio gradually drops from 0.082 to 0.046 and remains within the range of 0.045 to 0.050 for 5 consecutive seconds, the duty cycle can be gradually reduced from 30% to 8%, the frequency drift range can be reduced from ±1.5kHz to ±0.2kHz, and the ultrasonic output can be stopped.

[0159] In this way, the system outputs a strong cavitation effect only when there are signs of an increase in mass transfer resistance, and reduces the intensity of intervention in a timely manner after the resistance decreases, so that the biofilm is in a low disturbance state.

[0160] To make the judgment condition of high frequency ratio decline clearer, the controller performs the feedback judgment after S7 in the following order: first, it collects the stator current signal of the current analysis cycle and calculates the current high frequency ratio. Then read the high-frequency percentage saved in the previous period. and current ultrasound output parameters;

[0161] Then make a judgment Is it less than If so, it indicates that the high-frequency disturbance component in the pump load is weakening after ultrasound intervention; further judgment is needed. Whether it has entered a stable range or fallen below the pullback criterion ;

[0162] The controller will only reduce the output intensity when both the relative decrease from the previous cycle and the fallback criterion are met simultaneously. The purpose of this setting is that a simple small decrease does not necessarily mean that the resistance state has been restored. It is necessary to combine the stable range or the fallback criterion for secondary confirmation in order to avoid premature reduction of ultrasonic output.

[0163] Fallback Criteria The physical meaning is: a logical boundary value used to determine whether the current fluid resistance has recovered from an abnormally enhanced state to an acceptable state; It is not required to be a single constant; it can be determined based on the stable operating data obtained during the equipment commissioning phase.

[0164] The preferred embodiment is to... Set as Or set to recent The average high-frequency proportion of each stable cycle plus an additional margin, of which A value of 5 to 30 can be used; if the equipment exhibits significantly different normal background values ​​at different load stages, separate values ​​can be established for low load, medium load, and high load. ;

[0165] thus, The source clearly corresponds to the device's historical stable data, and its decision-making role is as a condition for allowing output reduction: when Still higher Even at that time The decrease compared to the previous cycle only indicates that the resistance is improving, and the controller can maintain the current output or make a small, tentative adjustment; when Below Only when this time is reached can it be considered that the current resistance has entered an acceptable range, and a synchronized downward adjustment can be implemented;

[0166] Synchronous downsampling can be understood as jointly weakening multiple control dimensions according to the same recovery trend, rather than simply changing a single parameter; specifically, the following order can be adopted: prioritize reducing the duty cycle to decrease the cumulative effect time of the cavitation microjets; if If the frequency drift range is reduced after several consecutive cycles, the cavitation bubble scale changes tend to converge. If it remains stable, the number of working zones is further reduced or the driving voltage is lowered, and finally the state is switched to maintenance or shutdown.

[0167] The technical considerations behind the above sequence are as follows: the duty cycle corresponds to the duration of ultrasonic action, which is the most direct to adjust and the most sensitive to system recovery; the frequency drift range corresponds to the cavitation bubble scale adjustment dimension, which is suitable as a second-level fine attenuation method; the number of partitions and the driving voltage belong to a larger-scale output level switching, which is suitable as a subsequent energy-saving step; after this processing, the output down-adjustment process has a clear hierarchy and causal relationship, rather than a general reduction in power.

[0168] To avoid frequent ultrasound start-stop cycles caused by slight fluctuations in the high-frequency proportion around the threshold, the controller can also be set with hysteresis rules and a minimum hold time. The hysteresis rule means that the criteria used to enter the down-adjustment condition are different from the criteria used to re-enhance the output. The down-adjustment criterion can be... The criteria for reinforcing the output can be adopted. Add a hysteresis of 0.003 to 0.02;

[0169] Minimum hold time refers to maintaining the system for at least 1 to 10 analysis cycles after each level of downgrade before allowing the next downgrade judgment to proceed. By using hysteresis and minimum hold time, the controller can reduce malfunctions caused by instantaneous noise or level fluctuations, thereby improving long-term operational stability.

[0170] Before step S1, the following steps are included: S0, starting the control jet pump 3 to form a multi-stage internal circulation jet field in the ground tank 1 through the central jet pipe 5 and jet nozzle 6;

[0171] Step S0 is used to establish a stable macroscopic flow field foundation before current spectrum analysis and ultrasonic conditioning; the controller sends a start command to the drive circuit of jet pump 3, and jet pump 3 runs at rated speed or preset variable frequency speed, and output liquid is transported upward along the central jet pipe 5 and ejected through the horizontally radial jet nozzles 6 evenly distributed at the top.

[0172] The so-called multi-stage internal circulation jet field refers to the formation of multiple horizontal high-speed jets by the nozzle jet inside the tank. These jets collide with the tank wall and turn downward or tangentially, and then superimpose with the bottom suction flow and the middle circulation to form a multi-layer circulation structure of rising, expanding, falling, and re-suction. This structure is used to suspend biological packing, uniformly disperse sludge, and maintain the stability of the solute concentration field, providing a repeatable load background for subsequent state identification based on the current spectrum.

[0173] The parameters for establishing the multi-stage internal circulation jet field can be set according to the equipment size; the inner diameter of the central jet tube 5 can be 50mm to 250mm; the four nozzles are distributed at equal angles, and the flow velocity of each nozzle can be 1.5m / s to 6.0m / s, preferably 2.5m / s to 4.5m / s;

[0174] The nozzle centerline can be parallel to the horizontal plane or slightly deflected upwards by 5° to 15° to take into account both the turbulence of the upper liquid and the suspension of the packing. After the jet pump 3 is started, the controller can be set to a stable running period of 30 seconds to 10 minutes. After the main flow field in the tank is formed and the liquid level fluctuation enters the set range, the S1 sampling step will be entered. The reason for this setting is that when the jet pump 3 is first started, there is a starting current impact on the motor and the flow state in the tank is not yet stable. If the spectrum is collected immediately, the electrical transients and fluid field establishment transients are easily misjudged as resistance anomalies.

[0175] Taking a 3m³ device as an example, the flow rate of jet pump 3 is set to 45m³ / h, the nozzle flow rate is 3.1m / s, and after 120s of startup, the packing suspension height reaches more than 85% of the effective liquid depth, the bottom deposition thickness is less than 30mm, and the current waveform changes from the startup transition state to the stable operation state. At this time, entering S1 can obtain a reference spectrum that meets the preset signal-to-noise ratio.

[0176] The S0 step also provides fluid renewal conditions for subsequent ultrasonic action, enabling the local disturbances generated by the cavitation microjets to diffuse more quickly to the surrounding packing mass.

[0177] In step S7, the cavitation microjet penetrates the laminar boundary layer on the surface of the biofilm without changing the macroscopic flow velocity of the jet pump 3.

[0178] The cavitation microjet effect in step S7 focuses on local boundary layer regulation, rather than changing the overall circulation flow rate; the macroscopic flow velocity here refers to the velocity distribution of the main circulating fluid established by the jet pump 3 through the central jet pipe 5 and the jet nozzle 6; the laminar boundary layer refers to the low-velocity mass transfer resistance layer formed by viscosity in the liquid region immediately adjacent to the biofilm surface.

[0179] Traditional treatment methods often thin the boundary layer by increasing the rotation speed of the jet pump 3, but this will simultaneously increase the shear force throughout the entire reactor, causing large-scale shedding of mature biofilm. In this embodiment, the rotation speed and flow rate of the jet pump 3 are kept constant, and cavitation bubbles are generated and collapsed at local locations only by the ultrasonic transducer array 7 to form microscale jets pointing towards the biofilm surface.

[0180] The velocity of this microscale jet is much higher than that of the bulk flow, but its effective range is limited to the vicinity of the transducer array and the area adjacent to the biofilm surface. Therefore, it can weaken the boundary layer without significantly increasing the global shear level.

[0181] In practice, the operating frequency of the jet pump 3 can be fixed at the rated frequency or maintained at the set variable frequency value. The controller does not directly increase the pump speed due to the biofilm equivalent stiffness exceeding the limit, but only adjusts the duty cycle and frequency drift of the ultrasonic transducer array 7.

[0182] The motor speed, pump outlet pressure and nozzle flow rate of jet pump 3 are monitored during the same period. If the fluctuation range is controlled within ±3% of the rated value, it can be determined that the macroscopic flow rate remains unchanged. After the intervention of ultrasound, the cavitation bubbles collapse within 0.1 mm to 5 mm from the surface of the biofilm, forming directional microjet and local turbulence, which locally cuts off or compresses the originally thick laminar boundary layer.

[0183] For mature biofilms on the surface of plastic suspension packing, the boundary layer thickness can reach hundreds of micrometers in high-viscosity mixtures; after ultrasonic intervention, the reduction in boundary layer thickness can be observed to reach a preset ratio through tracer dye diffusion test, and the fluctuation range of the pump outlet flow meter reading is maintained within ±3% of the rated value.

[0184] Taking the working conditions of jet pump 3 with a flow rate of 60 m³ / h, ultrasonic reference frequency of 28 kHz, and duty cycle of 30% as an example, after maintaining jet pump 3 without speed adjustment and ultrasonic operation for 5 minutes, the high frequency ratio of current dropped from 0.079 to 0.052, and no large-area visible detachment of biofilm on the packing surface was observed. This indicates that the improvement in mass transfer mainly comes from the weakening of the boundary layer rather than the increase in macroscopic flow velocity.

[0185] This implementation reflects the correspondence between method features and mechanical structure, namely, the jet pump 3 is responsible for providing a stable main circulation, and the ultrasonic transducer array 7 is responsible for local penetration of the laminar boundary layer on the biofilm surface. The two have a clear division of labor, which facilitates long-term stable operation.

[0186] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Those skilled in the art will understand that many more variations and modifications can be made based on the teachings of this application, and all such variations and modifications fall within the scope of protection claimed in this application.

Claims

1. A ground-based intelligent sewage treatment device, characterized in that, include: The above-ground tank (1) serves as the main load-bearing frame, and a support base (2) is fixedly connected to the bottom of the above-ground tank (1). The jet pump (3) is fixedly connected to the bottom center of the ground tank (1) by flange bolts (4). The jet pump (3) is equipped with a drive motor. The output end of the jet pump (3) is connected to a central jet pipe (5) that extends vertically upward. The top of the central jet pipe (5) is evenly distributed with horizontally radial jet nozzles (6). The ultrasonic transducer array (7) includes a piezoelectric ceramic transducer (8), which is bonded to the lower middle region of the inner wall of the above-ground tank (1) by an array of epoxy resin (9). The above-ground tank (1) is filled with suspended biological packing material for attaching biofilm; the centripetal vortex guide plate (10) is fixed to the top liquid level of the above-ground tank (1) by a stainless steel bracket (11). The centripetal vortex guide plate (10) is in the shape of an inverted frustum cone, with a backflow gap (12) between its outer edge and the inner wall of the above-ground tank (1), and a central opening (13) formed on its inner edge. The conical surface of the centripetal vortex guide plate (10) is stamped with guide vanes (14) that are inclined in a clockwise direction. The controller connects to and controls the operation of the jet pump (3) and the ultrasonic transducer array (7).

2. The intelligent wastewater treatment equipment on the ground according to claim 1, characterized in that, The controller integrates a current spectrum analysis module, which is connected to the stator current sampling circuit of the jet pump (3) drive motor.

3. The intelligent wastewater treatment equipment on the ground according to claim 1, characterized in that, The ultrasonic transducer array (7) is configured to generate cavitation microjets in the sewage medium of the above-ground tank (1), the duration of the cavitation microjets and the cavitation bubble collapse scale being adjusted by the output signal of the controller.

4. The intelligent wastewater treatment equipment on the ground according to claim 1, characterized in that, The guide vanes (14) of the centripetal vortex guide plate (10) are configured to convert the upflow energy generated by the jet pump (3) into a centripetal horizontal circulation, thereby forming a negative pressure center at the central opening (13).

5. The intelligent wastewater treatment equipment on the ground according to claim 1, characterized in that, The stainless steel supports (11) are evenly distributed in the circumferential direction at the top of the above-ground tank (1).

6. A control method for an on-ground intelligent sewage treatment device according to any one of claims 1-5, characterized in that, include: S1. Collect the stator current signal of the drive motor of the jet pump (3) and perform fast Fourier transform on the stator current signal to extract the current spectrum distribution characteristics. S2. Calculate the internal micro-resistance state of the fluid based on the current spectrum distribution characteristics, extract the ratio of the sum of harmonic component amplitudes to the fundamental component amplitude in the preset high-frequency analysis interval of the current spectrum to obtain the high-frequency ratio; and obtain the calibration high-frequency ratio, which is the average high-frequency ratio measured in advance by the equipment under the rated operating conditions of clean water. S3. Subtract the calibrated high-frequency ratio under the clear water state from the current high-frequency ratio to obtain the deviation value, and multiply the deviation value by the dynamic viscosity conversion factor to obtain the equivalent dynamic viscosity of the current wastewater. S4. Multiply the equivalent dynamic viscosity by the biofilm deformation coefficient to obtain the equivalent stiffness of the biofilm. S5. Determine whether the equivalent stiffness of the biofilm is greater than a preset safety threshold. If it is less than or equal to the safety threshold, maintain the current operating state and continue monitoring. If the value is greater than the safety threshold, the equivalent stiffness of the biofilm is subtracted from the safety threshold to obtain the excess value, and then the excess value is multiplied by a preset control gain to calculate the compensation amount. S6. The compensation amount is converted into duty cycle adjustment command and working frequency command, and applied to the ultrasonic transducer array (7). S7. Cavitation bubbles are generated by the ultrasonic transducer array (7) to form cavitation microjets to adjust the local equivalent dynamic viscosity and gas-liquid interface tension inside the above-ground tank (1).

7. The control method according to claim 6, characterized in that, In step S6, the duration of the cavitation microjet is changed by adjusting the duty cycle corresponding to the duty cycle adjustment command, and the collapse scale of the cavitation bubble is changed by adjusting the operating frequency corresponding to the operating frequency command.

8. The control method according to claim 6, characterized in that, The S7 step further includes: real-time monitoring of the high-frequency ratio in the stator current signal; when the high-frequency ratio falls back to a preset stable range or below a preset fall criterion, the output intensity of the ultrasonic transducer array (7) is simultaneously reduced; wherein the preset fall criterion is the sum of the high-frequency ratio calibrated by clear water and the preset normal operation additional margin.

9. The control method according to claim 6, characterized in that, Before step S1, the process includes: S0, controlling the jet pump (3) to start, and forming a multi-stage internal circulation jet field in the ground tank (1) through the central jet pipe (5) and the jet nozzle (6).

10. The control method according to claim 6, characterized in that, In step S7, the cavitation microjet penetrates the laminar boundary layer on the surface of the biofilm without changing the macroscopic flow rate of the jet pump (3).

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