Efficient intelligent mine wastewater treatment control method

Abstract

The invention relates to the technical field of wastewater treatment, and discloses an efficient intelligent mine wastewater treatment control method which comprises the following steps: applying an ultrasonic standing wave field to wastewater to form a pollutant enrichment area and a relative clear water area; acquiring electrical response characteristics of the pollutant enrichment area; comparing the electrical response characteristic obtained in real time with a preset target response characteristic, and generating an error signal to determine a frequency adjustment amount; finally, the driving frequency of the ultrasonic standing wave field is dynamically adjusted based on the frequency adjustment amount, and self-adaptive resonance closed-loop control is formed. By constructing closed-loop feedback, the optimal resonant frequency of the system can be tracked and locked in real time, and high efficiency and stability of the pre-enrichment process are ensured. In addition, the structured water flow formed by the method is favorable for realizing targeted addition of a flocculating agent and low-energy-consumption bridging reaction at the downstream, so that the medicament consumption, the energy consumption and the sludge yield are remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a high-efficiency intelligent mine wastewater treatment control method. BACKGROUND

[0002] Mine wastewater usually contains a large amount of suspended particles, has the characteristics of high turbidity and complex composition, and efficient and low-cost treatment is the focus of the industry for a long time.

[0003] As a new physical treatment technology, the use of ultrasonic standing wave field for pre-concentration of suspended particles in wastewater can effectively improve the local concentration of pollutants, reduce the burden of the subsequent separation unit, and show good application prospects. The core of this technology is to drive dispersed micro-particles to the pressure node or anti-node plane of the sound field by acoustic radiation force, thereby forming a highly concentrated area of pollutants in the fluid.

[0004] However, the existing sound field pre-concentration technical solutions have significant limitations in practical application. Most of these solutions use open-loop control, that is, a fixed frequency set in the debugging stage is used to drive the ultrasonic transducer. The premise of this control method is to assume that the system is in a constant and ideal working environment. However, in the industrial field, the water quality (such as turbidity, particle concentration, conductivity) and working condition parameters (such as flow rate, temperature) of the wastewater to be treated are continuously and dynamically changing. These changes will directly affect the acoustic properties of the fluid medium, causing the optimal resonance frequency of the entire system to drift.

[0005] When this frequency drift occurs, a mismatch occurs between the fixed driving frequency and the actual optimal resonance frequency of the system. This mismatch will cause the coupling efficiency between the sound field energy and the fluid to drop sharply, and thus the stability of the ultrasonic standing wave field and the particle aggregation efficiency will be greatly reduced. Ultimately, this instability of the pre-concentration effect will be directly transmitted to the subsequent treatment unit, not only weakening the final treatment effect of the entire process flow, but also failing to take advantage of the theoretical advantages of this technology in energy saving and consumption reduction. SUMMARY

[0006] The purpose of the present application is to provide a high-efficiency intelligent mine wastewater treatment control method, which solves the problem of frequency mismatch caused by the inability to adapt to working condition fluctuations in the existing sound field enrichment technology using a fixed driving frequency, and thus causes unstable and low-efficiency pollutant pre-concentration.

[0007] To achieve the above object, the present application realizes a high-efficiency intelligent mine wastewater treatment control method through the following technical solutions. First, an ultrasonic standing wave field is applied to the flowing wastewater, and pollutants are pre-concentrated to form a pollutant-rich area and a relatively clean water area flowing downstream. Subsequently, the electrical response characteristics of the pollutant-rich area are obtained. Then, the real-time obtained electrical response characteristics are compared with the preset target response characteristics to generate an error signal, and the frequency adjustment amount is determined according to the error signal. Finally, based on the frequency adjustment amount, the driving frequency of the ultrasonic standing wave field is dynamically adjusted, thereby forming a self-adaptive resonant closed-loop control.

[0008] In a preferred technical solution, the method further comprises, before or simultaneously with obtaining the electrical response characteristics, electrochemically modifying the pollutant-rich area by applying a pulsed electric field to the pollutant-rich area through the electrode array of the pulsed electric field module. In particular, the step of obtaining the electrical response characteristics can utilize or multiplex the electrode array as a sensing electrode, by collecting instantaneous voltage and instantaneous current signals, and using fast Fourier transform algorithm or the like to calculate the electrical impedance value, conductivity value or equivalent capacitance value as the electrical response characteristics. This design integrates the modification and sensing functions in one, simplifying the system structure.

[0009] Further, the preset target response characteristics can be obtained through calibration. The calibration process is to lock the electrical response characteristic value corresponding to the moment when a physical parameter (such as turbidity, particle concentration or particle size) capable of representing the physical aggregation state of the pollutant-rich area measured by an external verification sensor for monitoring reaches its extreme value as the control target for subsequent closed-loop operation by performing frequency scanning.

[0010] In the implementation of the control algorithm, a proportional-integral control algorithm can be used to calculate the frequency adjustment amount according to the error signal. To improve the robustness of the control system, the algorithm can also include an anti-integral saturation module, which temporarily stops the accumulation of the integral term when the calculated frequency adjustment amount output reaches the preset boundary of the driving frequency, to prevent the excessive accumulation of the integral term from affecting the stable recovery of the control system when the system is subjected to a large disturbance.

[0011] In addition, the method of the present application can also include a downstream flocculation separation step. After the above-mentioned closed-loop control is stably operated, low-disturbance flocculation is performed on the structured water flow formed by the pollutant-rich area and the relatively clean water area. This process utilizes the fixed spatial position of the pollutant-rich area in the acoustic field to achieve targeted injection of flocculants through a nozzle. Subsequently, the water flow passes through a specific low average velocity gradient (e.g., 10s -1 to 70s -1The design utilizes the high collision probability brought by the particles pre-concentrated in the pollutant enrichment zone to efficiently form larger and denser macro-flocs under low energy consumption of fluid, and finally realizes efficient solid-liquid separation.

[0012] In summary, the present application includes at least one of the following beneficial technical effects:

[0013] 1. By constructing an adaptive resonant closed-loop control based on the electrical response characteristics of the pollutant enrichment zone, the present application can track and lock the optimal resonant frequency of the system in real time. This design overcomes the technical defect of the existing open-loop system that causes the enrichment efficiency to decrease due to wastewater operating condition fluctuations, ensuring that the pre-enrichment step of the ultrasonic standing wave field can always automatically operate at the optimal physical operating point.

[0014] 2. The present application uses the structured water flow formed by the acoustic field to achieve targeted injection of flocculant into the pollutant enrichment zone, greatly reducing the amount of reagent added. At the same time, the design of the low-shear bridging reaction zone downstream takes advantage of the high collision probability brought by the particles pre-concentrated, efficiently forming macro-flocs under very low mixing energy consumption, thereby improving the solid-liquid separation efficiency and achieving source reduction of sludge.

[0015] 3. By multiplexing the electrode array, the present application integrates the electrode for electrochemical modification with the sensing electrode for obtaining electrical response characteristics. This integrated design avoids the need for additional independent sensors for sensing functions, simplifying the system hardware configuration and internal wiring, thereby reducing manufacturing costs and subsequent operation and maintenance difficulties. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of the method of the present application;

[0017] Figure 2 is a schematic diagram of the ultrasonic electrochemical sensing coupling structure of the present application;

[0018] Figure 3 is a principle block diagram of the adaptive resonant closed-loop control algorithm of the present application;

[0019] Figure 4 is a structural schematic diagram of the low-disturbance flocculation and separation unit of the present application. DETAILED DESCRIPTION

[0020] The following will be described in detail with reference to the accompanying Figure 1 - the accompanying drawings Figure 4 , the present application will be further described in detail.

[0021] With reference to the accompanying Figure 1 , the present application provides an efficient intelligent mine wastewater treatment control method, which comprises the following steps:

[0022] S100: applying an ultrasonic standing wave field to the mine wastewater, the ultrasonic standing wave field having a driving frequency, so as to make pollutant particles in the wastewater aggregate and form a pollutant enrichment zone;

[0023] S200: applying a pulsed electric field to the pollutant enrichment zone, and obtaining an electrical response characteristic of the pollutant enrichment zone while the pulsed electric field is applied or after the pulsed electric field is applied;

[0024] S300: determining a frequency adjustment amount of the ultrasonic standing wave field based on the electrical response characteristic and a preset target response characteristic;

[0025] S400: dynamically adjusting the driving frequency using the frequency adjustment amount;

[0026] S500: adding a flocculating agent to the wastewater treated by the pulsed electric field, and performing flocculation separation.

[0027] The method of the present application can be executed by a high-efficiency intelligent mine wastewater treatment control system. The wastewater treatment control system can be a dedicated controller in terms of physics, such as a programmable logic controller (PLC), a microcontroller unit (MCU), or an industrial control computer. The dedicated controller is internally configured with a processor, a memory, and an I / O interface for communication with external devices, and runs program instructions for implementing the control method of the present application. The wastewater treatment control system can be functionally divided into a plurality of software modules that cooperate with each other. These software modules can run on the dedicated controller and specifically include:

[0028] The acoustic field application module is used to execute step S100.

[0029] The electric field application and sensing module is used to execute step S200.

[0030] The frequency adjustment amount determination module is used to execute step S300.

[0031] The driving frequency adjustment module is used to execute step S400.

[0032] The flocculation separation control module is used to execute step S500.

[0033] Next, the specific implementation of each step in the embodiment of the present application will be described in detail.

[0034] In step S100, the mine wastewater is continuously introduced into an ultrasonic standing wave field reaction chamber. The ultrasonic standing wave field reaction chamber can be a flow channel with a predetermined geometric shape (such as a rectangular or tubular shape).

[0035] An ultrasonic standing wave field generator is disposed on the reaction chamber for applying an ultrasonic standing wave field. In one embodiment, the ultrasonic standing wave field generator comprises at least one ultrasonic transducer and a reflecting element.

[0036] The ultrasonic transducer (e.g., a piezoelectric ceramic transducer) is mounted on one side wall of the reaction chamber, and the reflecting element is mounted on the other side wall opposite to the side wall. The ultrasonic transducer is electrically connected to a signal generator.

[0037] The signal generator is controlled by a controller in subsequent steps (e.g., S300 and S400), which provides a driving frequency to the signal generator. The signal generator generates an excitation electrical signal based on the driving frequency .

[0038] The ultrasonic transducer converts the excitation electrical signal into high-frequency mechanical vibrations and applies an acoustic field in the mine wastewater in the reaction chamber. The acoustic field is reflected by the reflecting element and superimposed between the ultrasonic transducer and the reflecting element to form a stable ultrasonic standing wave field.

[0039] The driving frequency is a frequency adjustment amount (e.g., S400) determined by the controller according to subsequent steps (e.g., S300) for dynamic adjustment to adapt the ultrasonic standing wave field to the working condition changes.

[0040] Under the action of the ultrasonic standing wave field, the pollutant particles are subjected to acoustic radiation force. The acoustic radiation force is due to the difference in acoustic properties between the pollutant particles and the wastewater medium (water), including density and compressibility.

[0041] The acoustic radiation force is a time-averaged force, whose direction and magnitude depend on the acoustic property contrast between the pollutant particles and the wastewater medium, as well as the position of the pollutant particles in the ultrasonic standing wave field.

[0042] In one embodiment, when the density of the pollutant particles is greater than or the compressibility is less than that of the wastewater medium (e.g., coal dust, rock particles), the pollutant particles are subjected to acoustic radiation force pushing them to the pressure node of the ultrasonic standing wave field.

[0043] In another embodiment, when the density of the pollutant particles is less than or the compressibility is greater than that of the wastewater medium (e.g., oil droplets), the pollutant particles are subjected to acoustic radiation force pushing them to the pressure anti-node of the ultrasonic standing wave field.

[0044] Therefore, the acoustic radiation force drives pollutant particles of different properties to overcome fluid drag and migrate directionally to the pressure node or pressure anti-node of the ultrasonic standing wave field, which is the mechanism of acoustic focusing enrichment.

[0045] In the continuous flow condition, the aforementioned micro-migration of individual pollutant particles driven by acoustic radiation force is macroscopically manifested as the reconfiguration of the spatial distribution of pollutants in the wastewater.

[0046] Specifically, a large number of pollutant particles, after migrating to the respective pressure nodes or anti-nodes, will gather to form multiple thin layers or planes of high particle concentration, which are perpendicular to the propagation direction of the acoustic field.

[0047] As the overall fluid of the mine wastewater continuously flows through the ultrasonic standing wave field reaction chamber, the high-concentration particle planes formed in the cross-section are manifested as multiple parallel high-concentration fluid layers in the flow direction.

[0048] Therefore, the wastewater flowing out of the ultrasonic standing wave field reaction chamber is physically structured to form regions with pollutant concentrations significantly higher than the average concentration of the incoming water, and regions with pollutant concentrations significantly lower than the average concentration of the incoming water. The region with high pollutant concentration is defined as the pollutant enrichment zone of the present application; the region with low pollutant concentration is the relatively clean water zone.

[0049] Referring to the accompanying drawings Figure 2 In step S200, the pollutant enrichment zone formed after step S100 is transported to a pulsed electric field module.

[0050] The pulsed electric field module includes at least one pair or multiple pairs of electrode arrays arranged in the channel through which the pollutant enrichment zone flows. A pulsed electric field generator is electrically connected to the electrode arrays for applying a pulsed electric field to the flowing pollutant enrichment zone.

[0051] In one embodiment, the pulsed electric field has a high voltage amplitude and a pulse width of microseconds or nanoseconds.

[0052] The pulsed electric field generates a transient high-intensity electric field in the pollutant enrichment zone. The transient high-intensity electric field acts on the double-layer structure on the surface of the pollutant particles, changes the distribution of the surface charge of the particles, and thus regulates the Zeta potential of the pollutant particles.

[0053] The regulation of the Zeta potential (e.g., reducing its absolute value or making it close to zero) destroys the electrostatic repulsion between the pollutant particles, causing the particles to destabilize and reducing the energy barrier for subsequent flocculation separation in step S500.

[0054] At the same time, when the pulsed electric field is applied to the electrode array, the voltage is sufficient to induce electrolysis of water on the surface of the electrode (e.g., cathode and / or anode). The electrolysis reaction produces micro-bubbles, such as hydrogen and oxygen micro-bubbles, in situ inside the pollutant enrichment zone.

[0055] These microbubbles generated in-situ in the high concentration environment of the pollutant-rich zone provide micro-scale perturbation and can serve as attachment cores to assist the aggregation of destabilized pollutant particles.

[0056] In one embodiment, to achieve efficient electrochemical modification and electrolytic microbubble generation, the electrode array preferably employs stable electrode materials with high oxygen evolution potential and / or high hydrogen evolution potential. For example, the anode can employ boron-doped diamond (BDD) electrode or titanium-based electrode coated with lead dioxide (PbO2), while the cathode can employ titanium (Ti) electrode, stainless steel electrode or noble metal (e.g. Pt) coating electrode.

[0057] The pulse electric field generator is configured to provide pulses with specific parameters. In one preferred embodiment, the high voltage amplitude is set to a range of 1 kV / cm to 50 kV / cm of electric field strength; the pulse width is set to a range of 10 ns to 100 s; the pulse repetition frequency is set to a range of 100 Hz to 10 kHz. It is appreciated by those skilled in the art that these parameters, especially the voltage amplitude, can be adjusted according to the conductivity of the wastewater to be treated and the target modification effect, to control the energy consumption of the system while achieving Zeta potential regulation and microbubble generation

[0058] In this part of the operation of step S200, i.e. the acquisition of the electrical response characteristics, the detailed implementation is as follows:

[0059] In one preferred embodiment, the sensing unit is physically integrated with the pulse electric field module. Specifically, the electrode array used for applying the pulse electric field is multiplexed as the sensing electrode for acquiring the electrical response characteristics.

[0060] The acquisition of the electrical response characteristics is coordinated in time with the application of the pulse electric field. In one implementation, the sensing unit is configured to collect the instantaneous voltage signal across the electrode array and the instantaneous current signal flowing through the electrode array at the same time as the pulse electric field (or a pulse signal dedicated for detection) is applied . In another implementation, the sensing unit is configured to collect the voltage decay signal or the current relaxation signal on the electrode array within a preset time window after the end of the pulse electric field application, as and .

[0061] The collected and signals (which can be amplified, filtered and analog-to-digital converted) are transmitted to the controller.

[0062] The controller is configured to determine the electrical response characteristics based on the received and The signal is calculated in real-time from the electrical response characteristics .

[0063] is a parameter used to quantitatively characterize the current physical state of the pollutant enrichment zone.

[0064] In one embodiment, the electrical response characteristics are calculated as the electrical impedance value (or its modulus, phase angle) or the conductivity value of the pollutant enrichment zone between the electrodes. The electrical impedance value has a strong correlation with the concentration, size distribution, and surface charge state (i.e. Zeta potential) of the pollutant particles in the pollutant enrichment zone.

[0065] The higher the aggregation degree of the pollutant enrichment zone formed in step S100 (i.e. the better the enrichment effect), the more the electrical impedance value (or conductivity value) of the pollutant enrichment zone will deviate from the baseline value of the relatively clean water zone when the enrichment zone flows between the electrodes.

[0066] In one preferred embodiment, in order to separate the high-voltage pulse for modification from the signal for sensing, the sensing unit adopts a specific measurement strategy.

[0067] Method 1: The sensing unit applies a low-voltage alternating current probing signal of a specific frequency (e.g. 1 kHz or 10 kHz) during the pulse-off time of the high-voltage modification pulse, and measures the (i.e. impedance) through a high-precision LCR (inductance, capacitance, resistance) measurement module or an electrochemical workstation (EIS module).

[0068] Method 2: The high-voltage modification pulse itself is used as the probing signal. The sensing unit captures the transient waveform of the and through a high-bandwidth voltage probe and a current probe (e.g. a Rogowski coil), and collects the waveform through a high-speed digital oscilloscope or a data acquisition card (DAQ). The controller then calculates the based on the transient ohmic response or dielectric relaxation characteristics of the waveform.

[0069] To achieve this calculation, the controller or its associated sensing unit is fixed with an algorithm for processing the transient voltage signal and the transient current signal.

[0070] In one preferred embodiment, the algorithm is a Fast Fourier Transform (FFT) algorithm.

[0071] Specifically:

[0072] When method 1 (alternating current probing signal) is adopted: the FT algorithm is used to accurately extract the amplitude and phase information of the transient voltage signal and the transient current signal at the fundamental frequency of the alternating current probing signal. The controller then calculates the the complex impedance at that specific frequency point, and separate the electrical impedance value (i.e. the impedance modulus ), the conductivity value (related to the real part of the impedance) or the equivalent capacitance value (related to the imaginary part of the impedance) from it as the electrical response feature;

[0073] When method two (high-voltage modified pulse) is adopted: the FFT algorithm is applied to the collected complete instantaneous voltage waveform and instantaneous current waveform respectively to obtain their frequency spectrum and in the frequency domain. The controller further calculates to obtain the electrochemical impedance spectrum (EIS) covering a certain frequency range. The controller then extracts the electrical impedance value, conductivity value or equivalent capacitance value at one or more specific frequency points from the spectrum as the electrical response feature.

[0074] This electrical impedance (or conductivity) based sensing method has stronger anti-fouling ability and higher sensitivity than the traditional optical turbidity sensing, and is particularly suitable for the treatment of mine wastewater with high turbidity.

[0075] In other embodiments, may also be calculated as one or more feature values extracted from the time-domain waveform of or , such as the peak value of the current signal, the decay time constant of the impulse response, or the total charge transmitted in one pulse cycle. These feature values also reflect the dielectric and conductive properties of the contaminant enrichment zone.

[0076] In the operation of step S300, the controller receives the electrical response feature

[0077] At the same time, the controller retrieves the pre-set target response feature from its internal memory. is a reference value or a set of reference parameters.

[0078] In one embodiment, is measured and calibrated in S200 by running the ultrasonic standing wave field system under controlled experimental conditions (e.g. known optimal resonant frequency, stable water quality) and confirming in S100 that the most efficient contaminant enrichment state has been reached.

[0079] represents the electrical characteristics corresponding to the contaminant enrichment zone being in an optimal physical aggregation state (e.g. highest concentration, most ideal aggregation form). The controller performs a comparison operation to compare the real-time acquired electrical response feature a preset target response characteristic is compared to generate an error signal .

[0080] In one specific embodiment, the error signal is calculated as the difference between and , with the formula:

[0081] ;

[0082] The error signal quantitatively characterizes the deviation between the actual enrichment effect of the current ultrasonic standing wave field (S100) and the target enrichment effect.

[0083] When the driving frequency of the ultrasonic standing wave field deviates from the optimal resonance point due to changes in working conditions (e.g., water temperature, flow rate, pollutant concentration), the enrichment effect of S100 decreases, causing the measured in S200 to deviate from , thereby generating a non-zero error signal . .

[0084] The error signal is then used as input for subsequent processing in step S300 to determine the frequency adjustment amount.

[0085] In one specific calibration embodiment, is obtained as follows: during the system debugging phase, using wastewater under the target working condition, the controller performs a frequency scanning program, i.e., the driving is slowly changed within a preset range (e.g., 1.9 MHz to 2.1 MHz).

[0086] During this scanning process, the sensing unit records the change curve of in real time. At the same time, an external, independent verification sensor (e.g., an online turbidity meter or particle image analyzer set downstream of S100 but upstream of S200) is used to monitor the actual physical enrichment degree of the pollutant enrichment zone.

[0087] When the external verification sensor indicates that the enrichment effect reaches a peak (e.g., the turbidity of the enrichment zone is highest or the particle aggregation morphology is optimal), the controller locks the corresponding electrical response characteristic value at this moment and stores it as . This value is then used as a fixed control target during the normal closed-loop operation of the system.

[0088] At this stage of step S300, the controller (specifically, the internal frequency lock controller module thereof) receives the generated error signal As input. The frequency-locked controller is configured with a specific control law or algorithm for converting the error signal into a frequency adjustment amount . representing the magnitude and direction of adjustment needed to eliminate the error , the current driving frequency .

[0089] In a preferred embodiment, the control law is a proportional-integral (PI) control algorithm. Specifically, the calculation of the frequency adjustment amount includes a proportional term , where is the proportional gain. This proportional term makes the frequency adjustment amount proportional to the magnitude of the current deviation, providing fast response capability to system disturbances (e.g. resonance point drift caused by instantaneous fluctuations in water temperature or contaminant concentration). The calculation of the frequency adjustment amount also includes an integral term , where is the integral gain. This integral term accumulates historical errors, with the core role being to eliminate the steady-state error of the system. That is, as long as the error signal continues to be non-zero (indicating has not yet reached ), the integral term will continue to grow or decrease, driving the frequency adjustment amount to continuously adjust until is precisely driven back to , at which point becomes zero, the integral term stops changing, and the system reaches a stable equilibrium point under the new operating conditions. The frequency adjustment amount is then determined by the formula

[0090] . In other embodiments, to improve dynamic response speed and suppress system overshoot, a derivative (D) term can also be introduced into the control algorithm, forming a PID controller. In more complex application scenarios, the frequency-locked controller can also employ a nonlinear control strategy, such as a fuzzy logic controller or an adaptive controller based on machine learning (e.g. reinforcement learning or neural networks), to handle the complex nonlinear mapping relationship that may exist between the electrical response characteristics and the optimal driving frequency . The controller periodically performs this calculation (e.g. once per second or according to the fluid residence time) to continuously generate the frequency adjustment amount and outputs it to step S400.

[0091] Further, to prevent the integral term To prevent excessive accumulation (i.e. integral windup), the control algorithm preferably further comprises an anti-windup module. The module temporarily stops the accumulation of the integral term when the calculated output reaches the upper or lower limit of the frequency adjustable range of the signal generator, thus ensuring that the control system can recover to a stable state more quickly after a large disturbance.

[0092] In step S400, the controller performs an actual update of the drive frequency and applies the operation. Specifically, the controller applies the frequency adjustment amount determined in step S300 to the current drive frequency value stored in the controller to calculate a new drive frequency for the next control period. In an embodiment, the update operation can be implemented by a simple addition operation:

[0093]

[0094] wherein and represent discrete control time steps.

[0095] After performing this calculation, the controller immediately outputs the updated drive frequency value as a new instruction parameter to the signal generator described in step S100.

[0096] Upon receiving the new instruction parameter, the signal generator immediately adjusts the frequency of its internal oscillator, thus changing the frequency of the excitation electrical signal output to the ultrasonic transducer.

[0097] The change in the excitation electrical signal frequency directly leads to a corresponding change in the mechanical vibration frequency of the ultrasonic transducer, and further changes the resonance state of the ultrasonic standing wave field formed in the reaction chamber.

[0098] Through this dynamic adjustment mechanism, the present application can actively and continuously fine-tune the ultrasonic standing wave field in response to the system state deviation indicated by the error signal . The direct purpose of this adjustment is to move the ultrasonic standing wave field to a new resonance point that can better match the electrical response characteristic to the target response characteristic , thus achieving adaptive tracking and locking of the optimal enrichment state of the pollutants.

[0099] Referring to the accompanying Figure 3 , steps S100, S200, S300 and S400 collectively constitute a complete adaptive resonance closed-loop control system for maintaining the optimal physical enrichment efficiency.

[0100] ​​​In this closed-loop system:

[0101] The ultrasonic standing wave field pre-concentration process in step S100 is the controlled object;

[0102] The electrical response feature acquired in step S200 serves as the feedback signal of the system. This signal innovatively converts the physical enrichment degree, which is difficult to measure directly online, into an electrical parameter that is easy to acquire and responds sensitively;

[0103] The comparison and calculation process in step S300 is the core of the controller of the system, which compares the feedback signal with the target value to generate an error signal and calculates the frequency adjustment amount

[0104] The frequency updating operation in step S400 is the execution action of the system, which applies the decision of the controller back to the controlled object.

[0105] The final effect of this closed-loop control is that the ultrasonic standing wave field system can automatically and in real time track and lock at the optimal resonance frequency point under the current working condition.

[0106] When the working condition of the mine wastewater changes, for example, water temperature fluctuation (affecting sound velocity), inflow velocity change (affecting the residence time of particles in the acoustic field), or changes in the concentration and composition of suspended solids (affecting the overall acoustic properties of the medium), these changes will cause the original optimal resonance frequency to drift

[0107] An open-loop system without feedback will thus cause a significant decrease in enrichment efficiency. However, under the closed-loop control of the present invention, this drift will immediately cause the physical state of the pollutant enrichment zone to change, which will be captured by the sensing unit in step S200 as a deviation. This deviation is quickly converted into a correction to the driving frequency through steps S300 and S400, thereby forcing the system operating point to return to the new optimal resonance point.

[0108] In summary, this closed-loop control mechanism turns a static acoustic field processing unit into an intelligent processing module with adaptive ability and robustness, ensuring that step S100 can always operate at the highest efficiency regardless of changes in external working conditions, continuously and stably providing wastewater in the best pre-treatment state for subsequent steps (modification in S200 and flocculation in S500).

[0109] In the flocculant dosing stage of step S500, the structured water flow after step S200, which already contains a pollutant enrichment zone and a relatively clean water zone, is introduced into a flocculant dosing and mixing unit.

[0110] Reference to the drawings Figure 4 The flocculant dosing and mixing unit comprises a flocculant storage and dosing system (e.g. comprising a storage tank, a metering pump). The flocculant (e.g. polyacrylamide PAM of high molecular weight, or inorganic polymer flocculant such as polyaluminum chloride PAC) is configured in solution form, and is injected precisely into the wastewater flow by the metering pump.

[0111] One of the core features of the present invention is that the implementation of this step is fundamentally different from the high-energy, fast-mixing stage (i.e. the mixing stage) in conventional flocculation processes.

[0112] Since in the previous step S100, the pollutants have been efficiently pre-concentrated into the pollutant-enriched zone, and in step S200, the surface charge characteristics of these particles have been modified (e.g. the Zeta potential has been regulated) to reduce the electrostatic repulsion between particles, the particles are now in a highly concentrated and easily flocculable activated or destabilized state.

[0113] Therefore, the primary goal of the flocculant dosing in step S500 is to avoid the use of high shear. High-shear mixing (e.g. using high-speed impellers) is not only unnecessary, but will also destroy the laminar flow structure of the pollutant-enriched zone painstakingly established in step S100, and will disperse the already concentrated particles back into the entire water body, thereby losing all the advantages brought by the previous steps.

[0114] In a preferred embodiment, the flocculant is dosed using a low-disturbance injection method. For example, the flocculant solution is injected into the flow channel through multiple thin tube nozzles at a low flow rate and pressure.

[0115] In another embodiment, the flocculant can be selectively and targetedly injected into the specific spatial location of the pollutant-enriched zone (the location of the enriched zone is determined by the standing wave field pattern in S100 and is stable), while the relatively clean water zone can not be dosed or dosed with less flocculant. This targeted dosing method can maximize the utilization of the reagent and significantly reduce the total dosage.

[0116] After the flocculant is injected, the water flow only needs to undergo a low-energy mixing process, such as flowing through a tubular mixer containing a small number of baffles, or a low-speed paddle stirring tank. The purpose of this process is only to enable the long polymer chains of the flocculant (in the case of PAM as a bridging agent) to fully contact and spread with the destabilized particles in the pollutant-enriched zone, to form particle-polymer-particle bridging.

[0117] Since the particles are highly concentrated in the enriched zone, the collision probability between particles is extremely high, and the bridging of the flocculant is almost instantaneous, thereby quickly sweeping and combining the small aggregates in the enriched zone into large and dense macro-flocs (i.e. alum flowers).

[0118] After the flocculant is dosed and initially dispersed with low disturbance, the water flow enters a low-shear bridging reaction zone. This stage corresponds to the slow mixing or reaction stage (i.e. coagulation stage) in traditional flocculation processes, but its internal mechanism and implementation have significant advantages due to the preceding steps of the present application.

[0119] The core purpose of this stage is to facilitate the flocculant molecules (e.g. long chains of high-molecular flocculants) injected in the nodes of step S500 to stretch and form physical bridges between the destabilized, highly concentrated pollutant particles, thereby growing the microscopic particle aggregates into macroscopic flocs (alum flowers) that are prone to settle or float.

[0120] The key to achieving this goal lies in the precise control of the flow field hydrodynamics, i.e. maintaining a low-shear environment.

[0121] Specifically, since in step S100 the pollutants have been efficiently enriched in a spatially well-defined pollutant enrichment zone, the average distance between particles has been minimized. Meanwhile, in step S200 the electrostatic repulsion forces on the particle surfaces have been weakened. These two prerequisites collectively create an ideal environment for flocculation to occur easily.

[0122] In this environment, after one end of a long chain of a high-molecular flocculant adsorbs onto the surface of a pollutant particle, the other part of the chain segment only needs to extend a very short distance to capture and adsorb onto another adjacent pollutant particle with a high probability. This process repeats, forming a stable bridge structure of particle-polymer long chain-particle.

[0123] The low-shear condition, i.e. a lower velocity gradient (G value) in the flow field, has a dual effect:

[0124] Providing effective collisions: It provides weak, gentle disturbance, enabling slow and effective contact and collision between particles and flocculant molecules, as well as between the tiny flocs being formed, creating opportunities for bridge formation.

[0125] Protecting formed bridges: It avoids the tearing and destruction of newly formed or forming polymer bridges by high shear forces (e.g. high-intensity turbulence generated by high-speed stirring). These bridges are relatively fragile before they are fully formed, and excessive hydrodynamic forces will break them, causing the flocculation process to fail or be inefficient.

[0126] In an embodiment, the low-shear bridging reaction zone can be a reaction tank with a specific internal structure, such as a stirrer with low rotational speed and large paddles, or a reaction pool designed as a tortuous flow channel, to ensure that the water flow as a whole flows slowly in a state close to laminar flow or weak turbulence.

[0127] In a preferred embodiment, the low shear environment is achieved by controlling the average velocity gradient (G value) of the flow field. Too high a G value will cause the flocs to break up, and too low a G value will cause insufficient collision of the particles. Given that the particles of the present application have been highly pre-concentrated in S100, the required collision probability is much higher than in conventional processes, and therefore the G value in this step can be controlled in a relatively low range, preferably between 10 s"1and 70 s"1. In embodiments employing a stirred tank, this G value can be precisely controlled by parameters such as the rotational speed of a low speed, large blade stirrer and impeller diameter In embodiments employing a tortuous flow path reaction tank, this G value is controlled by controlling the water flow rate and hydraulic radius (i.e. by the head loss)

[0128] Finally, under this low shear bridging action, all the pollutant particles in the pollutant-enriched zone are efficiently entrapped, swept and rapidly agglomerated into macro-flocs of large size, dense structure and high mechanical strength. Importantly, this process mainly occurs within the pollutant-enriched zone, while the relatively clean water zone, due to the extremely low concentration of particles and the small (or no) amount of flocculant added, experiences essentially no significant flocculation phenomenon, thus maintaining the structured separation state of the water flow, providing extremely favorable conditions for the subsequent solid-liquid separation step (e.g. sedimentation).

[0129] After the low shear bridging is completed, the pollutant-enriched zone and the relatively clean water zone, which were originally spatially separated, evolve into a sludge flow zone carrying almost all the macro-flocs (alum flowers), and a clean water flow zone with extremely low pollutant content. This structured water flow is then directed into a solid-liquid separation unit.

[0130] The solid-liquid separation unit can be a gravity sedimentation tank, a lamella / settling tube settler, a flotation tank or a continuous filtration device, etc. The favorable conditions created by the previous steps of the present application make the solid-liquid separation step here have an unprecedented high efficiency.

[0131] Firstly, the physical properties of the separation objects are extremely superior. The macro-flocs formed in the step are much larger in size and denser in structure, and have a much higher mechanical strength, than the flocs formed in conventional flocculation processes in homogeneous wastewater, because they are generated in an environment of pre-concentrated and surface destabilized particles, and grown through sufficient bridging action. According to the principles of fluid mechanics, this means that the macro-flocs have a significantly higher settling velocity (in gravity sedimentation) or floating velocity (in air flotation separation).

[0132] Secondly, the fluids to be separated have structural advantages. In a preferred embodiment, when a gravity settling tank is used, the macroscopic flocs in the sludge flow zone, due to their extremely high settling velocity, will rapidly sink to the bottom of the settling tank in a very short time and a very short horizontal travel distance, forming a high-concentration sludge layer. At the same time, the parallel flowing clear water flow zone, since it contains almost no suspended solids and flocs, has water quality that basically meets or exceeds the discharge standards when it enters the settling tank.

[0133] This efficient, structured separation process brings several significant technical and economic advantages:

[0134] Extremely high effluent quality: The treated effluent discharged from the supernatant zone of the solid-liquid separation unit mainly comes from the clear water flow zone, so its clarity and purity are extremely high and can consistently meet the standards.

[0135] Sludge reduction and concentration: Due to the high efficiency of the separation process and the fact that all flocs originate from a highly pre-concentrated area, the sludge layer formed at the bottom (or top) of the separation unit has a significantly higher solids content than traditional processes. This means that, for the same total amount of pollutants, the volume of wet sludge produced is smaller. This greatly reduces the difficulty and cost of subsequent sludge dewatering, transportation, and disposal.

[0136] Miniaturization and reduced investment: The extremely high settling or flotation velocities mean that the residence time required for wastewater in the solid-liquid separation unit to achieve the same separation effect is significantly reduced. Therefore, the effective volume or surface area of ​​the separation unit can be designed to be much smaller than that of traditional equipment, thereby significantly reducing the infrastructure investment and floor space required.

[0137] During the operation of the solid-liquid separation unit (e.g., a settling tank), the macroscopic flocs that settle to the bottom form a high-concentration sludge layer. The separation unit further includes a sludge discharge device, such as a scraper located at the bottom of the tank or a sludge discharge valve at the bottom of a conical hopper, which can be controlled based on electrical response characteristics sensed in S200. (It is related to the concentration of pollutants in the incoming water) or a set time period, automatically controlling the start and stop of the sludge discharge valve or scraper to achieve timed or quantitative sludge discharge, so as to maintain the stable operation of the separation unit and the output of high-concentration sludge. In summary, the solid-liquid separation in step S500 is the final manifestation of the synergistic effect of the entire process chain. It efficiently transforms the advantages of physical enrichment and chemical modification accumulated in the previous steps into a macroscopic and easily separable material form, thereby completing the high-standard purification of mine wastewater in a low-energy, small-footprint, and low-cost manner.

Claims

1. A highly efficient and intelligent method for treating and controlling mine wastewater, characterized in that: S100. An ultrasonic standing wave field is applied to the flowing wastewater to pre-aggregate pollutants and form a pollutant-rich zone and a relatively clear water zone downstream. S200, Obtain the electrical response characteristics of pollutant-rich areas; S300: Compare the real-time acquired electrical response characteristics with the preset target response characteristics to generate an error signal, and determine the frequency adjustment amount based on the error signal; S400. Based on the frequency adjustment amount, the driving frequency of the ultrasonic standing wave field is dynamically adjusted to form an adaptive resonant closed-loop control.

2. The efficient and intelligent mine wastewater treatment and control method according to claim 1, characterized in that, It also includes the following steps: Before or simultaneously with acquiring the electrical response characteristics, an electrochemical modification is performed by applying a pulsed electric field to the pollutant-rich region through the electrode array of the pulsed electric field module. Specifically, the step of obtaining the electrical response characteristics includes: Using the electrode array, or reusing the electrode array as a sensing electrode, the instantaneous voltage signal and instantaneous current signal of the pollutant enrichment area are collected, and the electrical response characteristics are calculated accordingly.

3. The efficient and intelligent mine wastewater treatment and control method according to claim 2, characterized in that, The electrical response characteristics are calculated using a fast Fourier transform algorithm as the electrical impedance, conductivity, or equivalent capacitance values ​​of the pollutant enrichment region between the electrode arrays.

4. The efficient and intelligent mine wastewater treatment and control method according to claim 1, characterized in that, The preset target response characteristic refers to the electrical response characteristic value obtained by frequency scanning or external verification sensor calibration, which is the value corresponding to the time when the driving frequency of the ultrasonic standing wave field causes a physical parameter of the pollutant enrichment area to reach a preset extreme value. The physical parameters include at least one of turbidity, particle concentration, or particle size.

5. The efficient and intelligent mine wastewater treatment and control method according to claim 1, characterized in that, The specific steps for determining the frequency adjustment amount based on the error signal include: A proportional-integral control algorithm is used to calculate the frequency adjustment based on the error signal, wherein the frequency adjustment is equal to the product of the error signal and the proportional gain, plus the product of the integral of the error signal and the integral gain.

6. The efficient and intelligent mine wastewater treatment and control method according to claim 5, characterized in that, The step of determining the frequency adjustment amount based on the error signal further includes: using an anti-integral saturation module to temporarily stop the accumulation of the integral term of the error signal when the calculated output of the frequency adjustment amount reaches the preset upper or lower limit of the driving frequency.

7. The efficient and intelligent mine wastewater treatment and control method according to claim 1, characterized in that, The step of dynamically adjusting the driving frequency of the ultrasonic standing wave field specifically includes: Add the current cycle's driving frequency to the frequency adjustment amount to obtain the driving frequency for the next cycle; The driving frequency of the next cycle is then output to the signal generator to update the actual operating frequency of the ultrasonic standing wave field.

8. The efficient and intelligent mine wastewater treatment and control method according to claim 1, characterized in that, It also includes step S500: After the dynamic adjustment step S400, a low-disturbance flocculant is added to the structured water flow containing the pollutant enrichment zone and the relatively clear water zone. After the low-disturbance flocculant is added, the water flow passes through the low-shear bridging reaction zone, which agglomerates the pollutant particles in the pollutant enrichment zone into macroscopic flocs. Finally, solid-liquid separation is performed on the water flow.

9. The efficient and intelligent mine wastewater treatment and control method according to claim 8, characterized in that, The low-disturbance flocculant addition step specifically includes: using the fixed spatial position formed by the pollutant enrichment zone on the ultrasonic standing wave field pressure node or anti-node plane, selectively and targetedly injecting flocculant through a nozzle into the specific spatial position through which the pollutant enrichment zone flows.

10. The efficient and intelligent mine wastewater treatment and control method according to claim 8, characterized in that, The low-shear bridging reaction zone has a duration of 10 seconds. -1 up to 70s -1 The average velocity gradient within the range; utilizing the high collision probability of pre-concentrated particles in the pollutant enrichment zone, under the low shear force conditions, the long chains of the flocculant are encouraged to form inter-particle bridging, thus forming the macroscopic flocs.

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