Circuit board wastewater heavy metal removal method and system

Abstract

The invention discloses a circuit board wastewater heavy metal removal method and system, and the method comprises the steps: monitoring the concentration and valence distribution of heavy metal ions in circuit board wastewater in real time, and generating wastewater heavy metal form distribution characteristics in combination with oxidation-reduction potential and pH value; based on wastewater heavy metal form distribution characteristics, adjusting an oxidation-reduction environment to generate heavy metal ion enriched wastewater; the method comprises the following steps: introducing heavy metal ion enriched wastewater into an electric flocculation reactor, applying a periodic electric field through a programmable pulse power supply to dissolve an aluminum or iron anode to release a multi-core hydroxyl complex, and carrying out a co-precipitation reaction with heavy metal ions to generate a flocculating constituent suspension; and introducing the flocculating constituent suspension into a rotational flow clarification and separation device, realizing mud-water separation through centrifugal sedimentation and inclined plate separation, outputting supernate, discharging the supernate after reaching the standard, and recovering precipitated sludge rich in heavy metals. By utilizing the embodiment of the invention, efficient breaking and separation of the complex-state heavy metals can be realized, and good environmental benefits and resource values are achieved.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically a method and system for removing heavy metals from circuit board wastewater. Background Technology

[0002] Wastewater generated during circuit board manufacturing contains high concentrations of heavy metal ions such as copper, nickel, and tin, which often form stable complexes with complexing agents like EDTA and citric acid, making it one of the most difficult industrial wastewaters to treat. Existing treatment methods mainly include chemical precipitation, ion exchange, and adsorption. Chemical precipitation involves adding sulfides or hydroxides to precipitate heavy metals, but its effectiveness in removing complexed heavy metals is limited, and it generates large amounts of chemical sludge. Ion exchange can achieve deep treatment, but the resin is easily contaminated by organic matter, resulting in high regeneration costs. Adsorption is limited by its adsorption capacity and is difficult to adapt to high-concentration wastewater treatment. More importantly, the quality of circuit board wastewater fluctuates greatly, and the distribution of heavy metals is complex. Traditional treatment methods with fixed process parameters cannot respond to changes in water quality in real time, leading to unstable treatment effects, high reagent consumption, and difficulty in achieving resource recovery of heavy metals. Therefore, there is an urgent need for a treatment method that can adapt to dynamic changes in water quality, efficiently remove complexed heavy metals, and simultaneously achieve resource recovery. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for removing heavy metals from circuit board wastewater, which overcomes the shortcomings of the prior art and can achieve efficient removal and separation of complexed heavy metals, thus having good environmental benefits and resource value.

[0004] One embodiment of this application provides a method for removing heavy metals from circuit board wastewater, the method comprising:

[0005] The concentration and valence distribution of heavy metal ions in circuit board wastewater are monitored in real time by an online multi-parameter water quality analyzer. The distribution characteristics of heavy metal speciation in wastewater are generated by combining redox potential and pH value.

[0006] Based on the distribution characteristics of heavy metal speciation in the wastewater, the complexed heavy metals in the wastewater are converted into free heavy metal ions by adding a directional conversion agent, and the redox environment is adjusted to generate heavy metal ion-enriched wastewater.

[0007] The heavy metal ion-enriched wastewater is introduced into an electrocoagulation reactor. A periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension.

[0008] The flocculent suspension is fed into a cyclone clarification and separation device, where mud and water are separated by centrifugal sedimentation and inclined plate separation. The supernatant is discharged in compliance with standards, and the precipitated sludge rich in heavy metals is recovered.

[0009] Optionally, the step of real-time monitoring of the concentration and valence state distribution of heavy metal ions in circuit board wastewater using an online multi-parameter water quality analyzer, combined with redox potential and pH value to generate the distribution characteristics of heavy metal speciation in the wastewater, includes:

[0010] Deploy an online multi-parameter water quality analyzer to continuously collect circuit board wastewater samples. Detect the concentration and valence state of heavy metal ions in real time through ion-selective electrodes and spectral analysis modules to generate a raw dataset of heavy metal ion concentration and valence state.

[0011] The raw dataset of heavy metal ion concentration and valence state was aligned with the synchronously collected redox potential and pH value time series. Outliers were removed and missing data were imputed using a data fusion algorithm to generate preprocessed multi-parameter water quality time series data.

[0012] Based on the pre-processed multi-parameter water quality time series data, the chemical speciation analysis model was applied to calculate the complexed form, free state ratio and valence distribution of each heavy metal, and a heavy metal speciation distribution matrix was generated.

[0013] By integrating the heavy metal speciation distribution matrix with the dynamic trends of redox potential and pH value, a feature vector of heavy metal speciation distribution in wastewater containing the concentration of each speciation, the dominant valence state, and the complexation strength is generated through a feature extraction algorithm.

[0014] Optionally, based on the distribution characteristics of heavy metal speciation in the wastewater, the step of converting complexed heavy metals in the wastewater into free heavy metal ions by adding a targeted conversion agent and adjusting the redox environment to generate wastewater rich in heavy metal ions includes:

[0015] The proportion of complexed heavy metals and the type of complexing agent are extracted from the distribution feature vector of heavy metal speciation in wastewater. The optimal type and dosage of targeted conversion agent are matched with the pre-stored reagent database to generate a targeted conversion agent dosing scheme.

[0016] According to the dosing plan, the dosing pump is automatically controlled to add the directional conversion agent to the wastewater. At the same time, the stirring device is started to promote the mixing of the agent and the wastewater, so that the complexed heavy metals undergo a decomplexing reaction and are converted into free ions, generating a wastewater sample after conversion.

[0017] The oxidation-reduction potential and pH value of the wastewater after conversion are monitored in real time. The oxidation-reduction environment is adjusted to the preset optimal range by adding oxidants or reductants through the feedback control system to maintain the stable existence of free heavy metals and generate adjusted enriched wastewater.

[0018] Rapid sampling and verification of the adjusted enriched wastewater is performed to detect the concentration of free heavy metal ions. If the target enrichment degree is not reached, the dosage of the reagent or the reaction time is adjusted and the process is returned to the step. The dosing pump is automatically controlled to add the directional conversion agent to the wastewater according to the dosing plan. Otherwise, qualified heavy metal ion enriched wastewater is output.

[0019] Optionally, the step of introducing the heavy metal ion-enriched wastewater into an electrocoagulation reactor, and applying a periodic electric field through a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxyl complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension, includes:

[0020] Heavy metal ion enrichment wastewater is introduced into the electrocoagulation reactor at a constant flow rate. At the same time, the pulse frequency, duty cycle and current density of the programmable pulse power supply are set according to the conductivity of the wastewater and the heavy metal load to generate the pulse power supply parameter configuration.

[0021] The programmable pulse power supply is activated, and a periodic electric field is applied to the aluminum or iron electrode according to the parameter configuration, which triggers the anodic dissolution and release of aluminum ions or ferrous ions, and forms polynuclear hydroxy complexes during the hydrolysis process, generating in-situ flocculants;

[0022] By utilizing the hydraulic circulation and aeration stirring within the reactor, the in-situ flocculant can fully contact the heavy metal ions in the wastewater, undergoing adsorption, bridging, and co-precipitation reactions to generate tiny floc particles, forming a primary floc suspension.

[0023] The changes in floc size and density are monitored by an online turbidity meter and particle analyzer. When the flocs reach the preset size, the pulsed electric field is stopped, and a mature floc suspension is output for separation.

[0024] Optionally, the step of passing the flocculent suspension into a cyclone clarification and separation device, achieving sludge-water separation through centrifugal sedimentation and inclined plate separation, outputting supernatant that meets discharge standards, and recovering precipitated sludge rich in heavy metals includes:

[0025] The flocculent suspension is continuously fed into the feed inlet of the cyclone clarification and separation device. The principle of centrifugal sedimentation is used to make the denser flocculents move towards the device wall and settle downwards, generating underflow concentrated sludge and overflow preliminary clear liquid.

[0026] The overflow pre-cleaned liquid is introduced into the inclined plate separation zone, where laminar flow sedimentation further removes residual fine suspended solids, improving solid-liquid separation efficiency and generating supernatant and sludge retained by the inclined plate.

[0027] The underflow concentrated sludge and the sludge intercepted by the inclined plate are combined and collected into a sludge storage tank, and dewatered using a plate and frame filter press to generate a dried sludge cake rich in heavy metals with a moisture content of less than 80%.

[0028] The supernatant is subjected to online water quality testing to ensure that the concentration of heavy metal ions and pH value meet the discharge standards before being discharged through the outlet. At the same time, the dried sludge cake is packaged and recycled.

[0029] Another embodiment of this application provides a heavy metal removal system for circuit board wastewater, the system comprising:

[0030] The monitoring module is used to monitor the concentration and valence distribution of heavy metal ions in circuit board wastewater in real time through an online multi-parameter water quality analyzer, and to generate the distribution characteristics of heavy metal speciation in wastewater by combining redox potential and pH value.

[0031] The conversion module is used to convert complexed heavy metals in the wastewater into free heavy metal ions by adding a directional conversion agent based on the distribution characteristics of heavy metal speciation in the wastewater, and to adjust the redox environment to generate wastewater rich in heavy metal ions.

[0032] An application module is used to introduce the heavy metal ion-enriched wastewater into an electrocoagulation reactor. A periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension.

[0033] The separation module is used to pass the flocculent suspension into a cyclone clarification and separation device, and achieve mud-water separation through centrifugal sedimentation and inclined plate separation, outputting supernatant that meets discharge standards and recovering precipitated sludge rich in heavy metals.

[0034] Another embodiment of this application provides a storage medium storing a computer program, wherein the computer program is configured to execute the method described in any of the preceding claims when running.

[0035] Another embodiment of this application provides an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the method described in any of the preceding claims.

[0036] Compared with existing technologies, the present invention provides a method for removing heavy metals from circuit board wastewater, which can achieve efficient removal and separation of complexed heavy metals, and has good environmental benefits and resource value. Attached Figure Description

[0037] Figure 1 Hardware structure block diagram of a computer terminal for a method of removing heavy metals from circuit board wastewater provided in an embodiment of the present invention;

[0038] Figure 2 A schematic flowchart of a method for removing heavy metals from circuit board wastewater provided in an embodiment of the present invention;

[0039] Figure 3This is a schematic diagram of a heavy metal removal system for circuit board wastewater provided in an embodiment of the present invention. Detailed Implementation

[0040] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] This invention first provides a method for removing heavy metals from circuit board wastewater. This method can be applied to electronic devices, such as computer terminals, specifically ordinary computers.

[0042] The following detailed explanation uses a computer terminal as an example. Figure 1 This is a hardware structure block diagram of a computer terminal for a method of removing heavy metals from circuit board wastewater provided in an embodiment of the present invention. Figure 1 As shown, the computer device includes a processor, memory, and network interface connected via a system bus, wherein the memory may include non-volatile storage media and internal memory.

[0043] See Figure 2 The present invention provides a method for removing heavy metals from circuit board wastewater, which may include the following steps:

[0044] S201 uses an online multi-parameter water quality analyzer to monitor the concentration and valence distribution of heavy metal ions in circuit board wastewater in real time, and combines redox potential and pH value to generate the distribution characteristics of heavy metal speciation in wastewater.

[0045] Specifically, an online multi-parameter water quality analyzer can be deployed to continuously collect circuit board wastewater samples. The concentration and valence state of heavy metal ions can be detected in real time through ion-selective electrodes and spectral analysis modules to generate a raw dataset of heavy metal ion concentration and valence state.

[0046] The core of this step is to stably deploy an online multi-parameter water quality analyzer at the inlet point of the circuit board wastewater treatment process. This enables continuous collection of wastewater samples and real-time sensing of multi-dimensional heavy metal indicators, forming a traceable set of raw detection data. This provides a basic data source for subsequent morphological analysis. The specific implementation method is as follows:

[0047] The online multi-parameter water quality analyzer is installed submerged in the central liquid level area of ​​the circuit board wastewater equalization tank. At this location, the wastewater is uniformly mixed and free of significant sedimentation dead zones, accurately reflecting the overall water quality characteristics of the wastewater. The equipment is installed 30 cm underwater, away from the influent impact zone and the tank wall interference zone, ensuring representative sampling. The equipment is equipped with an automatic continuous sampling mechanism. The sampling pump extracts wastewater samples at a constant flow rate of 200 ml per minute. The samples flow through a constant-temperature detection tank, where the temperature is stabilized at 25 degrees Celsius, eliminating the interference of temperature fluctuations on electrode detection accuracy. The sampling frequency is set to once per second, achieving uninterrupted real-time data acquisition.

[0048] The detection module consists of two parts: an ion-selective electrode assembly and a spectral analysis module. The ion-selective electrode assembly includes dedicated detection electrodes for typical heavy metal ions in circuit board wastewater, such as copper, nickel, lead, and cadmium. Each electrode has an independent ion-selective membrane, responding only to the target heavy metal ions with a response time of less than 10 seconds and a concentration detection accuracy of 0.01 mg / L. It can accurately capture changes in low concentrations of heavy metals. During detection, the electrodes output a potential signal positively correlated with the ion concentration, which is then converted to a concentration value through internal analog-to-digital conversion. The spectral analysis module uses ultraviolet-visible spectrophotometry. It allows light of a specific wavelength to penetrate the wastewater sample and distinguishes the valence state distribution of the target heavy metal based on the differences in the characteristic absorption peaks of heavy metal ions in different valence states. For example, it distinguishes between divalent and monovalent copper ions, and divalent and trivalent iron ions. The spectral resolution is 0.1 nm, and the valence state percentage detection accuracy is better than 5%.

[0049] After each sampling and testing is completed, the system automatically adds a timestamp accurate to milliseconds to the test data, and records the corresponding heavy metal name, concentration value, and valence state ratio information. All test data are stored in real time in chronological order without any filtering or modification, and the original fluctuation information during the testing process is completely preserved. Finally, a raw dataset of heavy metal ion concentration and valence state containing timestamps, heavy metal types, concentration values, and valence state distribution ratios is formed. This dataset provides unprocessed and real detection basis for subsequent multi-parameter fusion and speciation calculation.

[0050] The raw dataset of heavy metal ion concentration and valence state was aligned with the synchronously collected redox potential and pH value time series. Outliers were removed and missing data were imputed using a data fusion algorithm to generate preprocessed multi-parameter water quality time series data.

[0051] The core of this step is to unify the time dimension of multiple water quality parameters, eliminate errors caused by sensor delay and data loss, and form continuous, stable, and reliable multi-parameter time-series data through standardized preprocessing. The specific implementation method is as follows:

[0052] The online multi-parameter water quality analyzer is equipped with both an oxidation-reduction potential (ORP) electrode and a pH composite electrode. The ORP electrode has a detection range of -1999 mV to +1999 mV and a detection accuracy of ±1 mV, used to reflect the electron gain / loss capacity and redox environment of wastewater. The pH electrode has a detection range of 0 to 14 and a detection accuracy of ±0.01, used to reflect the acidity / alkalinity of wastewater. Both types of electrodes share the same sampling flow path with the heavy metal detection module, achieving synchronous sampling and output. Time series alignment is based on a unified millisecond-level timestamp, matching and binding heavy metal concentration, valence state, ORP, and pH data collected at the same time to eliminate time offsets caused by response delays from different sensors. The offset correction accuracy is controlled within 50 milliseconds, ensuring that all parameters correspond to the same wastewater sample state.

[0053] The data fusion algorithm employs a multi-sensor weighted fusion approach, setting the weights for heavy metal concentration (W_1) at 0.6, redox potential (W_2) at 0.2, and pH value (W_3) at 0.2. This approach enhances overall data stability while preserving the independent characteristics of each parameter. Outlier removal utilizes the 3σ criterion. First, the mean μ and standard deviation σ of the time-series data for each parameter are calculated. Data exceeding the range of μ minus 3σ to μ plus 3σ are identified as outliers. For example, abnormally high concentration data caused by transient shocks and abrupt data jumps due to electrode interference are both identified and removed. Missing data imputation uses a linear interpolation method with the formula X_inter=X_prev+(X_next-X_prev)×(t_inter-t_prev) / (t_next-t_prev), where X_inter is the imputed value at the missing time, X_prev and X_next are the adjacent valid data before and after the missing point, and t_inter, t_prev, and t_next are the corresponding timestamps. After imputation, the data gaps are filled to ensure the continuity of the time series data.

[0054] After alignment, anomaly removal, and interpolation, all parameters are arranged in an orderly manner at fixed time intervals, forming pre-processed multi-parameter water quality time-series data with uniform length, no breaks, and no noise. This data can be directly input into the chemical speciation analysis model to avoid error propagation affecting subsequent calculation results.

[0055] Based on the pre-processed multi-parameter water quality time series data, the chemical speciation analysis model was applied to calculate the complexed form, free state ratio and valence distribution of each heavy metal, and a heavy metal speciation distribution matrix was generated.

[0056] The core of this step is based on the theory of water chemical balance. Through model calculations, macroscopic detection parameters are transformed into microscopic heavy metal speciation information, and the existence forms and concentration distribution of various heavy metals are presented in a structured matrix format. The specific implementation method is as follows:

[0057] The chemical speciation analysis model is constructed based on a combined system of complexation equilibrium, hydrolysis equilibrium, and redox equilibrium. The model incorporates a database of stability constants for common complexing agents in PCB wastewater, including typical complexing components such as EDTA, ammonia, citric acid, and phosphate. Combined with the total heavy metal concentration, pH value, and redox potential from pretreated time-series data, the model calculates the speciation ratio of each heavy metal at each time step. The model's calculation logic is that, under defined acid-base and redox environments, heavy metal ions preferentially combine with highly stable complexing agents to form complexes, with the remaining portion existing as free hydrated ions. The model can simultaneously output concentration values ​​for multiple speciations, including free, single-complexed, and multi-complexed states.

[0058] Taking copper ions as an example, the model can calculate the concentration and percentage of free copper ions, EDTA-complexed copper, ammonia-complexed copper, and hydroxyl-complexed copper. For nickel ions, it can distinguish between free nickel, citrate-complexed nickel, and ammonia-complexed nickel, while retaining the speciation results of heavy metals in different valence states. The heavy metal speciation distribution matrix is ​​a two-dimensional structured data, with rows corresponding to different heavy metal types and columns corresponding to different existing forms. The matrix element M_i_j represents the real-time concentration of the j-th form of the i-th heavy metal, in milligrams per liter. The matrix also indicates the percentage of each form in the total concentration of that heavy metal.

[0059] The model calculation frequency is consistent with the sampling frequency, generating a set of morphological distribution data every second. All matrix data are stored continuously in chronological order, fully reflecting the dynamic change process of heavy metal morphology in wastewater. This matrix transforms abstract chemical morphology into a quantifiable set of values, providing accurate morphological basis for subsequent targeted conversion agent dosing.

[0060] By integrating the heavy metal speciation distribution matrix with the dynamic trends of redox potential and pH value, a feature vector of heavy metal speciation distribution in wastewater containing the concentration of each speciation, the dominant valence state, and the complexation strength is generated through a feature extraction algorithm.

[0061] The core of this step is to extract key characterization information from massive time-series morphological data, compress multidimensional matrix data into low-dimensional feature vectors, and form concise and complete heavy metal morphological distribution features, providing standardized input for subsequent drug dosing decisions. The specific implementation method is as follows:

[0062] First, a sliding window trend analysis method was employed, with a window length set at 10 minutes. Statistics were performed within the window on the heavy metal speciation distribution matrix, redox potential, and pH value. The window mean, volatility, and slope of change for each parameter were calculated to obtain the dynamic trend of parameter changes, eliminating the interference of instantaneous fluctuations and highlighting the overall water quality change patterns. Subsequently, a feature extraction algorithm was used to perform dimensionality reduction and fusion of multidimensional information, retaining the core features most valuable for decision-making, including the free state concentration, complexed state concentration, dominant valence state encoding, overall complexation strength index, average redox potential, and average pH value of each heavy metal.

[0063] The dominant valence state is represented by a numerical code, for example, divalent copper is coded as 1 and trivalent iron is coded as 3, which intuitively reflects the stable valence state of heavy metals. The complexation strength index I_comp is the core feature. The calculation formula is the total concentration of complexed heavy metals divided by the total concentration of heavy metals. The value ranges from 0 to 1. The closer the index is to 1, the higher the degree of complexation and the more difficult it is to remove directly. The closer the index is to 0, the higher the proportion of free state and the easier it is to flocculate and precipitate.

[0064] All the extracted core features are arranged in a fixed order to form a one-dimensional standardized feature vector, with the form V=[Cu_free,Cu_complex,Ni_free,Ni_complex,ORP_mean,pH_mean,I_comp,main_valence], where Cu_free is the concentration of free copper, Cu_complex is the concentration of complexed copper, Ni_free is the concentration of free nickel, Ni_complex is the concentration of complexed nickel, ORP_mean is the average redox potential, pH_mean is the average pH value, I_comp is the complexation strength index, and main_valence is the dominant valence state encoding. This feature vector is concise and complete, and can comprehensively characterize the overall morphological characteristics of heavy metals in circuit board wastewater. It can be directly input into the subsequent control system for intelligent matching of the type and dosage of targeted conversion agents.

[0065] S202, based on the distribution characteristics of heavy metal speciation in the wastewater, the complexed heavy metals in the wastewater are converted into free heavy metal ions by adding a directional conversion agent, and the redox environment is adjusted to generate heavy metal ion-enriched wastewater.

[0066] Specifically, the proportion of complexed heavy metals and the type of complexing agent can be extracted from the distribution feature vector of heavy metal speciation in wastewater. Combined with the pre-stored reagent database, the optimal type and dosage of targeted conversion agent can be matched to generate a targeted conversion agent dosing scheme.

[0067] The core of this step is to perform structured analysis on the previously generated heavy metal speciation distribution feature vector, extract key speciation information affecting heavy metal removal, and then determine the appropriate type and precise dosage of the targeted conversion agent suitable for the current wastewater quality through intelligent matching with a standardized reagent database, forming an automated dosing scheme that can be directly executed. The specific implementation method is as follows:

[0068] The wastewater heavy metal speciation feature vector is a one-dimensional numerical vector containing multiple core indicators. The system uses feature indexing to accurately analyze key parameters such as the proportion of complexed heavy metals, the proportion of free heavy metals, the complexation strength index, the dominant complexing agent type, and the total heavy metal concentration. The proportion of complexed heavy metals is the ratio of the concentration of complexed heavy metals to the total heavy metal concentration. The complexation strength index is used to characterize the tightness of the binding between heavy metals and complexing agents. The higher the value, the greater the difficulty in disentanglement. The dominant complexing agent type is analyzed through the corresponding encoded value in the feature vector. Common complexing agents in circuit board wastewater include EDTA, ammonia, citric acid, and phosphate. The stability of the coordination bonds formed between different complexing agents and heavy metals varies significantly, which is the core basis for selecting directional conversion agents.

[0069] The pre-stored reagent database is a standardized database that has been validated through multiple experiments. It contains parameters such as the type of targeted converter corresponding to different complexing agents, the effective dosage concentration range, the reaction pH range, and the decomposition efficiency. Each targeted converter in the database is labeled with its applicable scenario and decomposition mechanism. For example, a special composite decomposition converter is matched for strong complexing agents such as EDTA, an alkaline decomposition agent is matched for ammonia complexing heavy metals, and an oxidative decomposition agent is matched for weak complexing agents such as citric acid. The system uses the obtained complexing agent type, complexed state ratio, and total heavy metal concentration as matching inputs. A weighted matching algorithm is used to calculate the suitability score of each candidate converter. The suitability score calculation formula is S=W_1×S_type+W_2×S_ratio+W_3×S_con, where S is the total suitability score, W_1, W_2, and W_3 are the weight coefficients of complexing agent type, complexed state ratio, and heavy metal concentration, respectively, and S_type, S_ratio, and S_con are the matching scores of the corresponding dimensions. The converter with the highest score is selected as the best choice.

[0070] The dosage calculation employs a concentration-based back-calculation algorithm, using a target free state conversion rate of ≥95% as the basis. This is combined with real-time wastewater flow rate, total heavy metal concentration, and complexation strength index to determine the dosage per unit volume. The dosage unit is milligrams per liter (mg / L). In the example, when the total heavy metal concentration in the wastewater is 50 mg / L, the complexed state accounts for 80%, and EDTA is the dominant complexing agent, the optimal targeted converter dosage is set at 120 mg / L. A 10% to 20% adjustment margin is also reserved in the plan to cope with water quality fluctuations. The final targeted converter dosing plan includes complete information such as the targeted converter type, dosage per unit volume, total dosage, dosing point, dosing method, reaction time, and optimal pH range. The plan is stored as digital instructions and can be directly transmitted to the dosing control system for execution.

[0071] According to the dosing plan, the dosing pump is automatically controlled to add the directional conversion agent to the wastewater. At the same time, the stirring device is started to promote the mixing of the agent and the wastewater, so that the complexed heavy metals undergo a decomplexing reaction and are converted into free ions, generating a wastewater sample after conversion.

[0072] The core of this step is to achieve automated and precise dosing of the directional conversion agent according to the dosing plan. Mechanical stirring enhances the mass transfer and mixing of the agent and wastewater, promoting the directional decomposition reaction of complexed heavy metals, and converting the stable complexed form into directly removable free ions. The specific implementation method is as follows:

[0073] After receiving the digital instructions for the dosing plan, the dosing control system adjusts the output speed of the dosing pump according to the real-time wastewater flow signal to achieve continuous proportional dosing of the directional converter. The dosing pump is a metering diaphragm pump with a dosing accuracy controlled within ±2%. The dosing point is located in the turbulent water zone in the middle of the wastewater equalization tank, where the wastewater is evenly mixed, which shortens the agent diffusion time and avoids localized excessively high or low agent concentrations. During the dosing process, the remaining agent level in the storage tank is monitored in real time. When the remaining level is below 10%, a level warning is triggered to ensure continuous and uninterrupted dosing.

[0074] Simultaneously with the addition of the directional converter, the stirring device is automatically activated. The stirring device employs a top-mounted mechanical agitator, with a stirring speed set at 150 rpm. The agitator blade diameter is one-third the diameter of the reaction tank. This speed and blade size ensure effective mixing while avoiding excessive turbulence. The stirring duration is consistent with the decomplexing reaction time, set to 10 to 15 minutes, ensuring sufficient contact between the directional converter and the complexed heavy metals in the wastewater. After addition, the directional converter competitively binds with the complexing agent in the heavy metal complex, breaking the coordination bonds between the heavy metal and the complexing agent. This releases the encapsulated heavy metal ions, converting them into free hydrated heavy metal ions. This reaction can proceed at room temperature and pressure without additional heating or pressurization, making it suitable for continuous treatment of circuit board wastewater.

[0075] After the reaction continues for the set time, the system collects wastewater samples after conversion at the outlet of the reaction tank using an online sampler. The sampling flow rate is 100 ml per minute. The samples are immediately sent to the online detection unit for subsequent monitoring of oxidation-reduction potential and pH value. This sample is an intermediate product after the decomplexing reaction, and its water quality directly reflects the decomplexing effect, which is the basis for subsequent oxidation-reduction environment regulation.

[0076] The oxidation-reduction potential and pH value of the wastewater after conversion are monitored in real time. The oxidation-reduction environment is adjusted to the preset optimal range by adding oxidants or reductants through the feedback control system to maintain the stable existence of free heavy metals and generate adjusted enriched wastewater.

[0077] The core of this step is to stabilize the oxidation-reduction potential and pH value of the converted wastewater within the optimal range for the presence of free heavy metals through closed-loop feedback regulation. This prevents the free heavy metals from re-complexing or forming precipitates, thus creating a wastewater system with stable accumulation of heavy metal ions. The specific implementation method is as follows:

[0078] Oxidation-reduction potential (ORP) electrodes and pH composite electrodes are deployed in the pipeline for transporting the converted wastewater. Both types of electrodes collect data in real time at a frequency of once per second. The ORP monitoring range is -1000 mV to +1000 mV with an accuracy of ±1 mV, and the pH monitoring range is 0 to 14 with an accuracy of ±0.01. The monitoring data is transmitted to the feedback control system in real time. To address the requirement for stable free heavy metals in the circuit board wastewater, the optimal ORP range is preset to 150 mV to 250 mV, and the optimal pH range is 7.5 to 9.0. This range ensures that free heavy metal ions do not undergo hydrolysis and precipitation, nor do they recombine with residual complexing agents.

[0079] The feedback control system employs a PID control algorithm, comparing real-time monitored values ​​with preset optimal values, calculating the deviation, and outputting adjustment commands. When the oxidation-reduction potential (ORP) is below 150 mV, the wastewater is determined to be in a reducing environment, and the system controls the oxidant dosing pump to add oxidant to increase the ORP. When the ORP is above 250 mV, a reducing agent is added to decrease the ORP. When the pH is below 7.5, an alkaline regulator is added to increase the pH. When the pH is above 9.0, an acidic regulator is added to decrease the pH. The oxidant, reducing agent, and acid-base regulator are all added in continuous micro-dosing, with a single dosing not exceeding 50 mg / L, to avoid drastic fluctuations in water quality parameters. During the adjustment process, the stirring device operates continuously to ensure rapid and even mixing of the regulators.

[0080] When the oxidation-reduction potential and pH value remain stable within the preset optimal range for 3 consecutive minutes, the adjustment is considered complete. At this time, most of the heavy metals in the wastewater exist in the form of free ions, without re-complexation or precipitation. The concentration of heavy metal ions remains stable and evenly distributed, forming the adjusted enriched wastewater. This wastewater is the ideal influent for electrocoagulation treatment and can be stably transported to the subsequent electrocoagulation reactor.

[0081] Rapid sampling and verification of the adjusted enriched wastewater is performed to detect the concentration of free heavy metal ions. If the target enrichment degree is not reached, the dosage of the reagent or the reaction time is adjusted and the process is returned to the step. The dosing pump is automatically controlled to add the directional conversion agent to the wastewater according to the dosing plan. Otherwise, qualified heavy metal ion enriched wastewater is output.

[0082] The core of this step is to quickly detect and verify the treatment effect of the enriched wastewater, establish a closed-loop adjustment mechanism, ensure that the enrichment level of free heavy metals meets the standard, and if it does not meet the standard, automatically optimize the parameters and re-execute the decomposition process; if it meets the standard, it enters the next treatment unit. The specific implementation method is as follows:

[0083] The system collects instantaneous water samples at the outlet of the enriched wastewater after adjustment using a rapid sampling probe. It then uses a rapid photometric detection method to detect the concentration of free heavy metal ions in the water sample. The detection time is no more than 30 seconds, and the detection accuracy reaches 0.01 mg / L. It can simultaneously detect various typical heavy metal ions from circuit boards, such as copper, nickel, lead, and cadmium. At the same time, it calculates the enrichment degree of free heavy metals, which is the ratio of the concentration of free heavy metals to the total concentration of heavy metals. The preset target enrichment degree is greater than or equal to 95%, which is the core standard for determining whether the enriched wastewater is qualified.

[0084] If the test results show that the enrichment of free heavy metals is less than 95%, the system automatically determines that it has not met the standard, analyzes the reasons for not meeting the standard and generates an adjustment strategy. If the failure to meet the standard is due to incomplete decomposition of complexed heavy metals, the dosage of the directional conversion agent is increased by 10%. If the failure to meet the standard is due to insufficient reaction time, the stirring reaction time is extended by 2 to 3 minutes. If the failure to meet the standard is due to fluctuations in the redox environment, the potential and pH adjustment parameters are re-optimized. After the adjustment strategy is generated, the system automatically returns to the directional conversion agent addition step and re-executes the decomposition, mixing and adjustment process according to the updated parameters until the enrichment meets the standard.

[0085] If the test results show that the enrichment degree of free heavy metals is greater than or equal to 95%, the system determines that the enriched wastewater is qualified and automatically opens the effluent valve to continuously transport the qualified heavy metal ion enriched wastewater to the electrocoagulation reactor. Simultaneously, the system records operational data such as reagent dosage, reaction time, and water quality parameters for this treatment, updating the data to the water quality database to provide a reference for parameter adjustments in case of subsequent water quality fluctuations. Qualified heavy metal ion enriched wastewater has stable heavy metal ions and uniform water quality, which is suitable for the influent requirements of the electrocoagulation reactor, laying a good foundation for the subsequent polynuclear hydroxyl complex coprecipitation reaction.

[0086] S203, the heavy metal ion enriched wastewater is introduced into the electrocoagulation reactor, and a periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which co-precipitate with heavy metal ions to generate flocculent suspension.

[0087] Specifically, heavy metal ion enriched wastewater can be introduced into the electrocoagulation reactor at a constant flow rate. At the same time, the pulse frequency, duty cycle and current density of the programmable pulse power supply can be set according to the conductivity of the wastewater and the heavy metal load to generate the pulse power supply parameter configuration.

[0088] The core of this step is to achieve stable feeding of wastewater rich in heavy metal ions, and to refine the parameters of the electrocoagulation pulse power supply by combining real-time wastewater quality parameters, so as to provide stable electric field conditions for efficient anode dissolution and in-situ flocculant generation. The specific implementation method is as follows:

[0089] Heavy metal ion enrichment wastewater is transported to the electrocoagulation reactor via a variable frequency constant flow pump. The pump adopts a closed-loop speed control mode, and the influent flow rate is stably set at 1.5 cubic meters per hour, with the flow rate fluctuation error controlled within ±0.1 cubic meters per hour. The constant flow rate ensures that the hydraulic residence time of the wastewater in the reactor remains consistent, avoiding insufficient reaction due to excessive flow rate or reduced treatment efficiency due to excessively slow flow rate. A water distribution plate is installed at the reactor inlet to ensure that the wastewater is evenly distributed in the electrode area, improving the uniformity of contact between the electric field and the wastewater.

[0090] While the wastewater is being fed in, an online conductivity sensor monitors the conductivity of the enriched wastewater in real time. The conductivity range covers 1000 to 5000 micro-Siemens per centimeter with a detection accuracy of ±1%. This parameter directly reflects the conductivity of the wastewater and is the core basis for setting the electric field parameters. The heavy metal load is calculated by multiplying the real-time influent flow rate by the concentration of free heavy metals, with the unit being grams per hour. It represents the total amount of heavy metals entering the reactor per unit time. The heavy metal load of circuit board wastewater usually fluctuates between 5 and 50 grams per hour.

[0091] The core parameters of a programmable pulse power supply include pulse frequency, duty cycle, and current density. The pulse frequency determines the speed of electric field alternation and is set according to conductivity. When the conductivity is below 2000 microsiemens per centimeter, it is set to 1000 Hz, and when the conductivity is above 2000 microsiemens per centimeter, it is set to 500 Hz. Low frequency is suitable for high conductivity wastewater to avoid electrode polarization, while high frequency is suitable for low conductivity wastewater to improve electrolysis efficiency. The duty cycle is the ratio of pulse energizing time to the total cycle time, and the setting range is 30% to 60%. Under medium heavy metal load, a 40% duty cycle is used to balance anode dissolution efficiency and energy consumption. The current density is the current value passing through a unit electrode area, in milliamperes per square centimeter. It is adjusted according to the heavy metal load. When the load is below 20 grams per hour, it is set to 8 milliamperes per square centimeter, and when the load is above 20 grams per hour, it is increased to 12 milliamperes per square centimeter to ensure full release of metal ions.

[0092] The pulse frequency, duty cycle, and current density parameters that have been matched above are integrated, and auxiliary parameters such as electrode switching cycle and protection voltage are added to generate a standardized pulse power supply parameter configuration file. This configuration is in the form of digital instructions and can be directly read and executed by the pulse power supply control system without the need for manual adjustment.

[0093] The programmable pulse power supply is activated, and a periodic electric field is applied to the aluminum or iron electrode according to the parameter configuration, which triggers the anodic dissolution and release of aluminum ions or ferrous ions, and forms polynuclear hydroxy complexes during the hydrolysis process, generating in-situ flocculants;

[0094] The core of this step is to drive an electrochemical dissolution reaction at the electrodes through a periodic electric field, transforming the anode material into metal ions and gradually hydrolyzing and polymerizing them to generate a polynuclear hydroxy complex in-situ flocculant with strong adsorption capacity. This provides a core carrier for the co-precipitation of heavy metals. The specific implementation method is as follows:

[0095] After receiving the parameter configuration command, the pulse power supply starts and applies a periodic DC pulse electric field to the aluminum or iron electrodes in the reactor according to the set frequency, duty cycle and current density. The electrode group adopts a plate-type symmetrical structure with alternating anode and cathode. The electrode spacing is fixed at 15 mm. If the electrode spacing is too small, it is easy to short circuit. If it is too large, it will reduce the electric field efficiency. This spacing can ensure that the electric field uniformly covers the entire reaction area.

[0096] Under the influence of a periodic electric field, the anode material undergoes an oxidation-dissolution reaction. The aluminum anode loses electrons to generate trivalent aluminum ions, and the iron anode loses electrons to generate divalent ferrous ions. The ion release rate is positively correlated with the current density. The pulsed electric field can effectively eliminate the passivation film on the electrode surface, avoiding the electrode passivation problem of traditional DC electrocoagulation and improving the anode utilization rate. After the released aluminum and ferrous ions enter the wastewater, they undergo a stepwise hydrolysis reaction in the current weakly alkaline environment of pH 7.5 to 9.0. First, monohydroxy complexes are formed, and then they gradually polymerize through hydroxyl bridging to generate polynuclear, high-charge hydroxy complexes, such as aluminum-based thiol hydroxy complexes and iron-based polynuclear hydroxy iron polymers. These substances have large molecular weights and high positive charge densities, making them the core in-situ flocculants in the electrocoagulation process.

[0097] The in-situ flocculant disperses immediately in the wastewater after generation, eliminating the need for external addition of dry powder or liquid agents. This avoids problems such as uneven dissolution and delayed addition of agents. The generation efficiency is highly matched with the electric field parameters. When the current density is stable, the flocculant concentration can be maintained at 50 to 150 mg / L. This concentration range has the best adsorption and co-precipitation effect on heavy metal ions in circuit board wastewater. The flocculant generation process is continuous and proceeds simultaneously with the removal reaction of heavy metal ions.

[0098] By utilizing the hydraulic circulation and aeration stirring within the reactor, the in-situ flocculant can fully contact the heavy metal ions in the wastewater, undergoing adsorption, bridging, and co-precipitation reactions to generate tiny floc particles, forming a primary floc suspension.

[0099] The core of this step is to enhance mass transfer through dual stirring of hydraulics and aeration, allowing the in-situ flocculant to fully collide and combine with free heavy metal ions. Through multiple mechanisms, stable flocculent particles are formed, completing the transformation of heavy metals from ionic to solid particles. The specific implementation method is as follows:

[0100] The electrocoagulation reactor has a built-in hydraulic circulation device. The wastewater at the bottom of the reactor is returned upward through a bottom jet pump, forming an up-and-down circulation flow. The circulation flow rate is three times that of the influent flow rate, which can make the in-situ flocculant evenly dispersed in the reactor and eliminate local concentration differences. At the same time, microporous aeration discs are arranged at the bottom of the reactor, and the aeration rate is controlled at 0.8 cubic meters per minute. The generated microbubbles drive water flow turbulence as they rise, further increasing the contact probability between flocculant and heavy metal ions. Aeration can also partially oxidize ferrous ions to ferric ions, enhancing the stability of polynuclear hydroxyl complexes. The aeration intensity is moderate, avoiding excessively large bubbles that break the nascent flocs.

[0101] The reaction between in-situ flocculants and heavy metal ions involves a triple mechanism of adsorption, bridging, and co-precipitation. First, the positive charge on the surface of polynuclear hydroxyl complexes combines with heavy metal cations through electrostatic adsorption, adsorbing free heavy metals onto the flocculant surface. Subsequently, high molecular weight hydroxyl complexes connect multiple adsorbed heavy metal complexes together through bridging. Finally, under the synergistic effect of complexation and precipitation, heavy metal ions and hydroxyl groups form stable hydroxide precipitates, which are encapsulated inside the flocculant. These three actions occur simultaneously, rapidly converting dissolved heavy metals into solid flocculent particles.

[0102] The floc particles generated in the initial stage of the reaction have a particle size of 1 to 5 micrometers and are tiny suspended particles. As the reaction proceeds, the particles continuously aggregate and grow. The color varies depending on the electrode material. The aluminum electrode produces grayish-white flocs, while the iron electrode produces yellowish-brown flocs. All flocs are uniformly dispersed in the wastewater without obvious sedimentation and stratification, forming a uniform primary floc suspension. The heavy metal removal rate in this suspension has reached more than 70%, laying the foundation for the subsequent maturation of the flocs.

[0103] The changes in floc size and density are monitored by an online turbidity meter and particle analyzer. When the flocs reach the preset size, the pulsed electric field is stopped, and a mature floc suspension is output for separation.

[0104] The core of this step is to monitor the growth status of the flocs in real time using online monitoring equipment, and precisely stop the electric field when the flocs reach the optimal settling size. This avoids excessive electrolysis which increases energy consumption or insufficient reaction which reduces the separation effect, and outputs a mature floc suspension that meets the separation requirements. The specific implementation method is as follows:

[0105] An online turbidity meter and a particle analyzer are installed in the upper middle part of the electrocoagulation reactor. The online turbidity meter has a range of 0 to 1000 NTU and an accuracy of ±1 NTU. Changes in turbidity indirectly reflect changes in the density and concentration of flocs. As the flocs mature, the turbidity of the suspension will first rise and then tend to stabilize. The particle analyzer uses the principle of laser scattering to monitor the equivalent particle size distribution of the flocs in real time. The monitoring range is 1 to 100 micrometers, which can accurately capture the growth process of the flocs.

[0106] To meet the requirements of cyclone separation of circuit board wastewater, the preset mature size of flocs is 25 micrometers. When the particle analyzer detects that the average particle size of the flocs is stable in the range of 23 to 27 micrometers for 30 consecutive seconds and the turbidity value fluctuates less than 5 NTU, the flocs are judged to have reached the mature state. Mature flocs have a dense structure, high density, and good settling performance, which can meet the requirements of subsequent cyclone clarification and inclined plate separation.

[0107] Upon receiving the maturity determination signal, the system immediately sends a command to stop the programmable pulse power supply, terminating anodic dissolution and in-situ flocculant generation. This prevents excessive electrolysis from causing floc fragmentation, increased energy consumption, and increased electrode wear. After the electric field is stopped, the hydraulic circulation and aeration stirring in the reactor continue to run for 1 minute to make the floc distribution more uniform. Then, the reactor discharge valve is opened, and the mature floc suspension is transported to the cyclone clarification and separation device at a constant flow rate. The suspension discharge process is undisturbed and without stratification, ensuring the integrity of the floc structure and providing optimal material conditions for subsequent mud-water separation.

[0108] S204, the flocculent suspension is passed into a cyclone clarification and separation device, and mud-water separation is achieved through centrifugal sedimentation and inclined plate separation. The supernatant is discharged in compliance with standards and the precipitated sludge rich in heavy metals is recovered.

[0109] Specifically, the flocculent suspension can be continuously fed into the feed inlet of the cyclone clarification and separation device. The principle of centrifugal sedimentation is used to make the denser flocculents move towards the wall of the device and settle downwards, generating underflow concentrated sludge and overflow preliminary clear liquid.

[0110] The flocculent suspension is continuously fed into the inlet of the cyclone clarification and separation device. Utilizing the principle of centrifugal sedimentation, the denser flocculents move towards the device wall and settle downwards, generating underflow concentrated sludge and overflow preliminary clarified liquid. This step, with centrifugal sedimentation as its core mechanism, achieves preliminary and efficient separation of flocculents from water, laying the foundation for subsequent deep clarification. The specific implementation method is as follows:

[0111] The cyclone clarification and separation device adopts a structure combining a conical and a cylindrical body. The feed inlet is positioned tangentially to the cylindrical body, ensuring that the suspension enters the device in a cyclone state, forming a stable centrifugal force field. The flocculent suspension is continuously fed into the feed inlet at a constant flow rate via a variable frequency delivery pump, with the flow rate controlled between 1.5 and 2 cubic meters per hour. This flow rate range ensures sufficient centrifugal force without causing flocculent breakage due to excessive flow rate. A buffer chamber is set before feeding to eliminate feed pressure fluctuations and ensure that the fluid entering the cyclone chamber is uniform and stable.

[0112] After the flocculent suspension enters the device, it rotates at high speed under the tangential feeding. Based on the principle of centrifugal sedimentation, the heavy metal flocculent particles, which have a density much greater than that of water, are subjected to a stronger centrifugal force and move rapidly toward the wall of the cylinder. Meanwhile, the clear liquid with a lower density concentrates in the central area of ​​the device, forming a stratified swirling state. After the flocculent particles adhere to the wall, they spiral down along the inner wall of the conical cylinder under the combined action of their own gravity and the downward thrust of the swirling flow, gradually accumulating and concentrating to form a high-concentration sludge slurry. Finally, it is discharged from the bottom outlet at the bottom of the device, which is the underflow concentrated sludge. At this time, the water content of the sludge is about 95% to 97%, and the enrichment of heavy metals is greatly improved.

[0113] The clear liquid located at the center of the device moves upward under the action of swirling flow and is discharged from the overflow port at the top. This part of the liquid is the initial clear liquid overflow after the initial solid-liquid separation is completed. Only a small amount of fine flocculent particles with a particle size of less than 5 micrometers remain in it. The turbidity is controlled between 30 NTU and 50 NTU. The swirling separation process is continuous and uninterrupted. Feeding, underflow discharge and overflow discharge are carried out simultaneously. There is no dead water zone inside the device. The separation efficiency is stable at over 85%. It can quickly separate a large number of mature flocculents from the suspension, which greatly reduces the processing load of subsequent separation units.

[0114] The overflow pre-cleaned liquid is introduced into the inclined plate separation zone, where laminar flow sedimentation further removes residual fine suspended solids, improving solid-liquid separation efficiency and generating supernatant and sludge retained by the inclined plate.

[0115] The overflow pre-clarified liquid is introduced into the inclined plate separation zone, where laminar flow sedimentation further removes residual fine suspended solids, improving solid-liquid separation efficiency and generating supernatant and sludge retained by the inclined plate. This step utilizes the principle of shallow sedimentation to enhance the removal of fine particles, ensuring that the effluent quality meets the clarification standards before discharge. The specific implementation method is as follows:

[0116] The inclined plate separation zone is located in the upper overflow channel of the cyclone clarification and separation device. It adopts a modular inclined plate structure. The inclined plates are made of lightweight and corrosion-resistant material. Each inclined plate is 500 mm long and 300 mm wide. The spacing between adjacent inclined plates is set at 50 mm. This spacing can ensure stable water flow and shorten the settling distance of fine suspended solids. The overall installation angle of the inclined plates is 60 degrees. This angle can maintain the laminar flow of water and allow the sludge settled on the surface of the inclined plates to slide down smoothly, avoiding sludge accumulation and blockage of the flow channel.

[0117] The overflow initial clear liquid slowly enters the inclined plate separation zone in a laminar flow state. The water flows smoothly in the narrow channel between the inclined plates, with a Reynolds number below 500, and is in a completely laminar flow state. Based on Stokes' sedimentation law, the remaining fine flocculent suspended matter settles downward under the action of gravity. The presence of the inclined plates greatly shortens the settling distance of the particles. Fine particles that originally required a long time to settle can contact the surface of the inclined plates and adhere within a short distance. The settling efficiency is more than 3 times higher than that of natural settling, which can effectively remove the fine suspended matter that was not separated in the swirling stage.

[0118] Fine flocs attached to the surface of the inclined plate continuously aggregate to form a thin layer of sludge. Under the action of gravity, the sludge slowly slides down the 60-degree inclined plate and eventually falls from the bottom of the plate into the sludge collection tank, forming the sludge intercepted by the inclined plate. This part of the sludge has a water content of about 96% and a heavy metal content consistent with the underflow concentrated sludge. After the water body is treated by the inclined plate separation zone, suspended solids and residual flocs are completely removed, the turbidity drops to below 5 NTU, and the heavy metal ion concentration is close to the discharge standard, forming a clear and transparent supernatant. The supernatant flows out smoothly from the outlet at the top of the inclined plate separation zone and enters the subsequent online monitoring stage. The inclined plate separation zone consumes no power and relies solely on gravity sedimentation to achieve deep clarification. It is stable in operation and easy to maintain.

[0119] The underflow concentrated sludge and the sludge intercepted by the inclined plate are combined and collected into a sludge storage tank, and dewatered using a plate and frame filter press to generate a dried sludge cake rich in heavy metals with a moisture content of less than 80%.

[0120] The underflow concentrated sludge and the sludge retained by the inclined plate are combined and collected in a sludge storage tank. A plate and frame filter press is then used for dewatering to produce a dried sludge cake rich in heavy metals with a moisture content of less than 80%. This step achieves sludge reduction and stabilization, facilitating heavy metal recovery and sludge disposal. The specific implementation method is as follows:

[0121] The underflow concentrated sludge at the bottom of the cyclone clarification and separation device and the sludge intercepted by the inclined plate at the bottom of the inclined plate separation zone are combined and collected into a closed sludge storage tank by gravity flow and sludge pump transportation. The sludge storage tank is equipped with a low-speed stirring device with a stirring speed of 30 revolutions per minute to continuously and slowly stir and prevent the sludge from settling and stratifying, thus avoiding caking and clogging of the discharge port. The effective volume of the storage tank is 2 cubic meters, which can store more than 2 hours of sludge production, ensuring the sludge temporary storage needs during the intermittent operation of the plate and frame filter press.

[0122] The plate and frame filter press adopts a fully automatic operation mode with automatic plate pulling and automatic feeding. There are 20 filter plates, and the filter cloth is made of special acid and alkali resistant and corrosion resistant material, which is suitable for the dewatering of heavy metal sludge. The sludge is transported from the sludge storage tank to the inside of the filter press through a high-pressure feed pump. The feed pressure is gradually increased to 0.4MPa. The sludge is evenly filled in the filter chamber between the filter plates, and the free water is initially removed. After the feeding is completed, the pressing stage begins. The pressing pressure is set at 0.8MPa and the pressing time lasts for 60 minutes. The high-pressure pressing forces the interstitial water and capillary water inside the sludge to be squeezed out and discharged through the filter cloth to the filtrate recovery tank. The filtrate is returned to the front end of the wastewater treatment for reprocessing to avoid the loss of heavy metals.

[0123] After pressing, the filter press automatically pulls the plate to unload the material. The dewatered sludge falls from the filter chamber, forming a hard, non-flowing block of dried sludge cake. The moisture content of the sludge cake is stably controlled below 80% by an online moisture content meter, which meets the moisture content requirements for subsequent treatment and recycling. The dried sludge cake is highly enriched with heavy metals, with copper, nickel and other typical heavy metals found in circuit boards accounting for 10% to 20%, giving it extremely high resource recovery value. The entire filtration and dewatering process is sealed, with no odor leakage and no sludge spillage, meeting environmental protection operation requirements.

[0124] The supernatant is subjected to online water quality testing to ensure that the concentration of heavy metal ions and pH value meet the discharge standards before being discharged through the outlet. At the same time, the dried sludge cake is packaged and recycled.

[0125] The supernatant undergoes online water quality monitoring to ensure that the concentration of heavy metal ions and pH value meet discharge standards before being discharged through the outlet. Simultaneously, the dried sludge cake is packaged and recycled. This step completes the final water quality verification and standardized product disposal, achieving both compliant wastewater discharge and resource recovery of heavy metals. The specific implementation method is as follows:

[0126] The supernatant generated in the inclined plate separation zone first flows through the online water quality monitoring unit. The monitoring unit is equipped with an online heavy metal analyzer, pH meter, and turbidity meter to monitor in real time the concentration of characteristic heavy metals such as copper ions, nickel ions, and lead ions in the circuit board wastewater, as well as three core indicators: pH value and turbidity. The heavy metal detection accuracy reaches 0.01 mg / L, the pH detection accuracy is ±0.01, and the turbidity detection accuracy is ±0.1 NTU. The detection data is updated once per second, and five sets of data are continuously collected and the average value is used as the final judgment basis to avoid misjudgment caused by instantaneous data fluctuations.

[0127] The system has a built-in emission standard threshold library, which compares the real-time detection data with the standard thresholds one by one. The system meets the standards if the copper ion concentration is below 0.5 mg / L, the nickel ion concentration is below 0.1 mg / L, the pH value is between 6 and 9, and the turbidity is below 5 NTU. After the standards are met, the system automatically opens the discharge valve, and the supernatant is output smoothly through the dedicated discharge port to achieve the standard discharge. If the detection data exceeds the standard, the system immediately closes the discharge valve and opens the return valve to return the supernatant that exceeds the standard to the front end of the electrocoagulation reactor for reprocessing until the water quality meets the standard before being discharged.

[0128] The dried sludge cakes are conveyed to the sealing and packaging station via a screw conveyor and sealed in special seepage-proof and leak-proof packaging bags. Each bag weighs 25 kg. The outer packaging bag is labeled with information such as sludge type, heavy metal composition, moisture content, and packaging time. The sealed sludge cakes are temporarily stored in the hazardous waste storage room and periodically handed over to qualified units for heavy metal extraction and recycling, realizing the resource recycling of heavy metals such as copper and nickel. The system automatically records the effluent quality data, sludge production, and packaging information for each batch, forming a complete operation ledger and providing data support for process optimization and environmental verification.

[0129] Another embodiment of the present invention provides a heavy metal removal system for circuit board wastewater, see [link to relevant documentation]. Figure 3 The system may include:

[0130] Monitoring module 301 is used to monitor the concentration and valence distribution of heavy metal ions in circuit board wastewater in real time through an online multi-parameter water quality analyzer, and generate the distribution characteristics of heavy metal speciation in wastewater by combining oxidation-reduction potential and pH value.

[0131] The conversion module 302 is used to convert complexed heavy metals in the wastewater into free heavy metal ions by adding a directional conversion agent based on the distribution characteristics of heavy metal speciation in the wastewater, and to adjust the redox environment to generate wastewater rich in heavy metal ions.

[0132] The application module 303 is used to introduce the heavy metal ion enriched wastewater into the electrocoagulation reactor. A periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which co-precipitate with heavy metal ions to generate flocculent suspension.

[0133] The separation module 304 is used to pass the flocculent suspension into the cyclone clarification and separation device, and achieve mud-water separation through centrifugal sedimentation and inclined plate separation, outputting supernatant that meets the discharge standards and recovering precipitated sludge rich in heavy metals.

[0134] This invention also provides a storage medium storing a computer program, wherein the computer program is configured to execute the steps in any of the above method embodiments when running.

[0135] This invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0136] Specifically, the aforementioned electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the aforementioned processor, and the input / output device is connected to the aforementioned processor.

[0137] The above description, based on the embodiments shown in the figures, details the structure, features, and effects of the present invention. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A method for removing heavy metals from circuit board wastewater, characterized in that, The method includes: The concentration and valence distribution of heavy metal ions in circuit board wastewater are monitored in real time by an online multi-parameter water quality analyzer. The distribution characteristics of heavy metal speciation in wastewater are generated by combining redox potential and pH value. Based on the distribution characteristics of heavy metal speciation in the wastewater, the complexed heavy metals in the wastewater are converted into free heavy metal ions by adding a directional conversion agent, and the redox environment is adjusted to generate heavy metal ion-enriched wastewater. The heavy metal ion-enriched wastewater is introduced into an electrocoagulation reactor. A periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension. The flocculent suspension is fed into a cyclone clarification and separation device, where mud and water are separated by centrifugal sedimentation and inclined plate separation. The supernatant is discharged in compliance with standards, and the precipitated sludge rich in heavy metals is recovered.

2. The method according to claim 1, characterized in that, The method involves real-time monitoring of the concentration and valence state distribution of heavy metal ions in circuit board wastewater using an online multi-parameter water quality analyzer, combined with redox potential and pH value to generate the wastewater heavy metal speciation characteristics, including: Deploy an online multi-parameter water quality analyzer to continuously collect circuit board wastewater samples. Detect the concentration and valence state of heavy metal ions in real time through ion-selective electrodes and spectral analysis modules to generate a raw dataset of heavy metal ion concentration and valence state. The raw dataset of heavy metal ion concentration and valence state was aligned with the synchronously collected redox potential and pH value time series. Outliers were removed and missing data were imputed using a data fusion algorithm to generate preprocessed multi-parameter water quality time series data. Based on the pre-processed multi-parameter water quality time series data, the chemical speciation analysis model was applied to calculate the complexed form, free state ratio and valence distribution of each heavy metal, and a heavy metal speciation distribution matrix was generated. By integrating the heavy metal speciation distribution matrix with the dynamic trends of redox potential and pH value, a feature vector of heavy metal speciation distribution in wastewater containing the concentration of each speciation, the dominant valence state, and the complexation strength is generated through a feature extraction algorithm.

3. The method according to claim 2, characterized in that, Based on the distribution characteristics of heavy metal speciation in the wastewater, the method involves adding a targeted conversion agent to convert complexed heavy metals in the wastewater into free heavy metal ions, and adjusting the redox environment to generate wastewater rich in heavy metal ions, including: The proportion of complexed heavy metals and the type of complexing agent are extracted from the distribution feature vector of heavy metal speciation in wastewater. The optimal type and dosage of targeted conversion agent are matched with the pre-stored reagent database to generate a targeted conversion agent dosing scheme. According to the dosing plan, the dosing pump is automatically controlled to add the directional conversion agent to the wastewater. At the same time, the stirring device is started to promote the mixing of the agent and the wastewater, so that the complexed heavy metals undergo a decomplexing reaction and are converted into free ions, generating a wastewater sample after conversion. The oxidation-reduction potential and pH value of the wastewater after conversion are monitored in real time. The oxidation-reduction environment is adjusted to the preset optimal range by adding oxidants or reductants through the feedback control system to maintain the stable existence of free heavy metals and generate regulated enriched wastewater. Rapid sampling and verification of the adjusted enriched wastewater is performed to detect the concentration of free heavy metal ions. If the target enrichment degree is not reached, the dosage of the reagent or the reaction time is adjusted and the process is returned to the step. The dosing pump is automatically controlled to add the directional conversion agent to the wastewater according to the dosing plan. Otherwise, qualified heavy metal ion enriched wastewater is output.

4. The method according to claim 3, characterized in that, The process of introducing the heavy metal ion-enriched wastewater into an electrocoagulation reactor, and applying a periodic electric field through a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxyl complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension, includes: Heavy metal ion enrichment wastewater is introduced into the electrocoagulation reactor at a constant flow rate. At the same time, the pulse frequency, duty cycle and current density of the programmable pulse power supply are set according to the conductivity of the wastewater and the heavy metal load to generate the pulse power supply parameter configuration. The programmable pulse power supply is activated, and a periodic electric field is applied to the aluminum or iron electrode according to the parameter configuration, which triggers the anodic dissolution and release of aluminum ions or ferrous ions, and forms polynuclear hydroxy complexes during the hydrolysis process, generating in-situ flocculants; By utilizing the hydraulic circulation and aeration stirring within the reactor, the in-situ flocculant can fully contact the heavy metal ions in the wastewater, undergoing adsorption, bridging, and co-precipitation reactions to generate tiny floc particles, forming a primary floc suspension. The changes in floc size and density are monitored by an online turbidity meter and particle analyzer. When the flocs reach the preset size, the pulsed electric field is stopped, and a mature floc suspension is output for separation.

5. The method according to claim 4, characterized in that, The process of passing the flocculent suspension into a cyclone clarification and separation device, achieving sludge-water separation through centrifugal sedimentation and inclined plate separation, outputting a supernatant that meets discharge standards, and recovering precipitated sludge rich in heavy metals includes: The flocculent suspension is continuously fed into the feed inlet of the cyclone clarification and separation device. The principle of centrifugal sedimentation is used to make the denser flocculents move towards the device wall and settle downwards, generating underflow concentrated sludge and overflow preliminary clear liquid. The overflow pre-cleaned liquid is introduced into the inclined plate separation zone, where laminar flow sedimentation further removes residual fine suspended solids, improving solid-liquid separation efficiency and generating supernatant and sludge retained by the inclined plate. The underflow concentrated sludge and the sludge intercepted by the inclined plate are combined and collected into a sludge storage tank, and dewatered using a plate and frame filter press to generate a dried sludge cake rich in heavy metals with a moisture content of less than 80%. The supernatant is subjected to online water quality testing to ensure that the concentration of heavy metal ions and pH value meet the discharge standards before being discharged through the outlet. At the same time, the dried sludge cake is packaged and recycled.

6. A heavy metal removal system for circuit board wastewater, characterized in that, The system includes: The monitoring module is used to monitor the concentration and valence distribution of heavy metal ions in circuit board wastewater in real time through an online multi-parameter water quality analyzer, and to generate the distribution characteristics of heavy metal speciation in wastewater by combining redox potential and pH value. The conversion module is used to convert complexed heavy metals in the wastewater into free heavy metal ions by adding a directional conversion agent based on the distribution characteristics of heavy metal speciation in the wastewater, and to adjust the redox environment to generate wastewater rich in heavy metal ions. An application module is used to introduce the heavy metal ion-enriched wastewater into an electrocoagulation reactor. A periodic electric field is applied by a programmable pulse power supply to dissolve the aluminum or iron anode and release polynuclear hydroxy complexes, which then undergo a co-precipitation reaction with the heavy metal ions to generate a flocculent suspension. The separation module is used to pass the flocculent suspension into a cyclone clarification and separation device, and achieve mud-water separation through centrifugal sedimentation and inclined plate separation, outputting supernatant that meets discharge standards and recovering precipitated sludge rich in heavy metals.

7. The system according to claim 6, characterized in that, The monitoring module is specifically used for: Deploy an online multi-parameter water quality analyzer to continuously collect circuit board wastewater samples. Detect the concentration and valence state of heavy metal ions in real time through ion-selective electrodes and spectral analysis modules to generate a raw dataset of heavy metal ion concentration and valence state. The raw dataset of heavy metal ion concentration and valence state was aligned with the synchronously collected redox potential and pH value time series. Outliers were removed and missing data were imputed using a data fusion algorithm to generate preprocessed multi-parameter water quality time series data. Based on the pre-processed multi-parameter water quality time series data, the chemical speciation analysis model was applied to calculate the complexed form, free state ratio and valence distribution of each heavy metal, and a heavy metal speciation distribution matrix was generated. By integrating the heavy metal speciation distribution matrix with the dynamic trends of redox potential and pH value, a feature vector of heavy metal speciation distribution in wastewater containing the concentration of each speciation, the dominant valence state, and the complexation strength is generated through a feature extraction algorithm.

8. The system according to claim 7, characterized in that, The conversion module is specifically used for: The proportion of complexed heavy metals and the type of complexing agent are extracted from the distribution feature vector of heavy metal speciation in wastewater. The optimal type and dosage of targeted conversion agent are matched with the pre-stored reagent database to generate a targeted conversion agent dosing scheme. According to the dosing plan, the dosing pump is automatically controlled to add the directional conversion agent to the wastewater. At the same time, the stirring device is started to promote the mixing of the agent and the wastewater, so that the complexed heavy metals undergo a decomplexing reaction and are converted into free ions, generating a wastewater sample after conversion. The oxidation-reduction potential and pH value of the wastewater after conversion are monitored in real time. The oxidation-reduction environment is adjusted to the preset optimal range by adding oxidants or reductants through the feedback control system to maintain the stable existence of free heavy metals and generate regulated enriched wastewater. Rapid sampling and verification of the adjusted enriched wastewater is performed to detect the concentration of free heavy metal ions. If the target enrichment degree is not reached, the dosage of the reagent or the reaction time is adjusted and the process is returned to the step. The dosing pump is automatically controlled to add the directional conversion agent to the wastewater according to the dosing plan. Otherwise, qualified heavy metal ion enriched wastewater is output.

9. A storage medium, characterized in that, The storage medium stores a computer program, wherein the computer program is configured to execute the method of any one of claims 1-5 when it is run.

10. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the method of any one of claims 1-5.

Images