A method for separating and purifying phosphorus and fluorine and recycling resources of high-concentration phosphorus and fluorine-containing wastewater

Abstract

This invention discloses a method for the separation, purification, and resource utilization of phosphorus and fluoride in high-concentration phosphorus and fluoride-containing wastewater, specifically relating to the field of water pollution control and treatment. The method includes online sampling of the high-concentration phosphorus and fluoride-containing wastewater to be treated, measuring the total phosphorus concentration, total fluoride concentration, conductivity, and initial pH; generating an influent dataset based on the measured results; obtaining sample water from the influent dataset, and performing acid-base titration on the sample water in at least two parallel control channels to determine a first and second pH point. By determining the first and second pH points in the parallel control channels based on the influent dataset and constructing candidate chemical treatment sequences with different calcium salt addition orders, a comprehensive score is calculated based on the solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, and washing loss to select the target chemical treatment sequence, and the solid-liquid separation and write-back results are performed accordingly.

Description

Technical Field

[0001] This invention relates to the field of water pollution control and treatment technology, and more specifically, to a method for the separation, purification and resource utilization of phosphorus and fluoride in high-concentration phosphorus and fluoride-containing wastewater. Background Technology

[0002] In the water pollution control and treatment of high-concentration phosphorus and fluoride wastewater, the mainstream practice in the industry is mainly to solve the problem of effluent compliance and reduce water pollution risk. Usually, the pH is adjusted according to the influent test results and agents such as calcium salts, aluminum salts or iron salts are added to make phosphorus and fluoride form precipitates or flocs in the reaction tank. Then, the solids are separated from the water through physical treatment steps such as sedimentation tanks and filters. The solids are discharged as sludge, and the water enters subsequent deep treatment or is discharged after meeting the standards. In application scenarios such as centralized treatment stations in chemical industrial parks, wastewater from multiple workshops is often mixed and intermittently discharged. The influent concentration fluctuates significantly with each batch and is often accompanied by hardness ions, silicon, salts, and a small amount of organic matter. The treatment system must meet the hard constraints of continuous operation, not frequent shutdowns for cleaning, and the desire to recover phosphate or fluoride salts as much as possible to reduce the disposal burden. Under this constraint, the mainstream practice will consistently produce phenomena that can be directly observed and verified. That is, even if the effluent indicators appear normal in some batches for a short period of time, the reaction section will still generate mixed sediments that are difficult to wash away, the filter pressure difference will rise faster, the sludge moisture content and composition will fluctuate more, the purity of resource recovery products will be difficult to stabilize, and scaling and clogging will be more likely to occur again after the mother liquor is reused. The reason is that it is difficult to determine in time whether to treat fluoride or phosphorus first in the current batch, and which pH range should be used to avoid phosphorus and fluoride being locked together in the same precipitate, by relying solely on the influent concentration and pH to select the reagents and dosage. The technical problem to be solved by this application is: in the multi-stage physical and chemical treatment process of high-concentration phosphorus and fluoride wastewater, how to reliably determine the pH range and treatment sequence of chemical treatment under the conditions of fluctuating influent batches and strong interference, so as to stably avoid blockage caused by mixed precipitation of phosphorus and fluoride and instability of resource products, and achieve the goal of water pollution control and treatment. Summary of the Invention

[0003] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for the separation, purification, and resource utilization of phosphorus and fluoride in high-concentration phosphorus- and fluoride-containing wastewater. This method involves determining a first and second pH point in a parallel control channel based on the influent dataset and constructing candidate chemical treatment sequences with different calcium salt addition orders. Then, a comprehensive score is calculated based on the solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, and washing loss to select the target chemical treatment sequence. The solid-liquid separation and write-back results are then executed accordingly to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater, comprising: S1. Online sampling of the high-concentration phosphorus and fluoride wastewater to be treated is performed to measure the total phosphorus concentration, total fluoride concentration, conductivity and initial pH. Based on the measurement results, an influent dataset is generated. S2. Based on the influent dataset, sample water is obtained by diverting the sample water, and acid-base titration is performed on the sample water in at least two parallel control channels to determine the first pH point and the second pH point, thereby generating at least two candidate chemical treatment sequences. The candidate chemical treatment sequences include calcium salt addition at the first pH point and the second pH point, respectively, with the addition amount calculated from the total phosphorus concentration and the total fluoride concentration, and outputting the control reaction slurry. S3. Perform physical solid-liquid separation on the control reaction slurry to obtain the control solid phase and control liquid phase, and measure the solid-liquid separation pressure difference growth rate, the residual total phosphorus concentration and residual total fluoride concentration of the control liquid phase, and the total phosphorus concentration and total fluoride concentration of the control solid phase washing liquid to generate a control index set. S4. Calculate the comprehensive score of each candidate chemical treatment sequence based on the control index set and select the candidate chemical treatment sequence with the smallest comprehensive score as the target chemical treatment sequence, and generate the target operating condition parameter set at the same time. S5. According to the target operating condition parameter set, acid-base adjustment and calcium salt addition are performed on high-concentration phosphorus and fluoride wastewater according to the target chemical treatment sequence to generate reaction slurry. Physical solid-liquid separation is then performed on the reaction slurry to obtain resource-based solid products and treated effluent, thereby reducing water pollution risk and achieving water pollution control and treatment.

[0005] In a preferred embodiment, S1 includes: S1-1. Within a single online sampling cycle, high-concentration phosphorus and fluoride-containing wastewater is continuously sampled at fixed time intervals to obtain the total phosphorus concentration sequence, total fluoride concentration sequence, conductivity sequence, and initial pH sequence, and to generate the influent original sequence set. S1-2. Calculate the median and median absolute deviation for each sequence in the original sequence set of influent, and remove the measurement points that deviate from the median by more than three times the median absolute deviation. Then calculate the arithmetic mean of the remaining measurement points and output the representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity and initial pH. S1-3. The representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity and initial pH are structurally combined and written into the same influent dataset entry to obtain the influent dataset.

[0006] In a preferred embodiment, S2 includes: S2-1. Based on the influent dataset, high-concentration phosphorus and fluoride-containing wastewater is diverted to obtain sample water and distributed to at least two parallel control channels. In each parallel control channel, acid or alkali solution is added to the sample water in increments using the minimum controllable dosing volume of the dosing device as the increment, and the pH value corresponding to each increment is recorded simultaneously to form a pH response sequence. When the pH difference corresponding to each consecutive increment is not greater than the pH measurement resolution, the titration is terminated and the pH response sequence is output. S2-2. Calculate the adjacent difference sequence and the second-order difference sequence in incremental order for the acid-base response sequence. Sort the candidate index set by the absolute value of the second-order difference sequence from largest to smallest. Select the two indices that make the corresponding acid-base difference the largest in the candidate index set as the first acid-base point and the second acid-base point to output the target titration point set. The adjacent difference sequence is the difference sequence obtained by subtracting the acid-base values ​​corresponding to two adjacent increments in the acid-base response sequence. The second-order difference sequence is the difference sequence obtained by subtracting two adjacent terms in the difference sequence.

[0007] In a preferred embodiment, S2 further includes: S2-3. Based on the target titration point set and the total phosphorus concentration, total fluoride concentration and sample water volume in the influent data set, calculate the dosage of the first calcium salt that allows fluoride and calcium ions to form calcium fluoride in stoichiometry and the dosage of the second calcium salt that allows phosphate and calcium ions to form phosphorus-containing calcium salt in stoichiometry. The arithmetic mean of the total phosphorus concentration and the total fluoride concentration of the sample water in the parallel control channel were calculated. The average total phosphorus concentration and the average total fluoride concentration were then substituted into the calculation formulas for the first calcium salt dosage and the second calcium salt dosage to obtain the updated dosage. At least two candidate chemical treatment sequences were generated. The candidate chemical treatment sequences were: first, the first calcium salt was added at the first pH point, and then the second calcium salt was added at the second pH point; and second, the second calcium salt was added at the first pH point, and then the first calcium salt was added at the second pH point. In each parallel control channel, acid-base adjustment and calcium salt addition were performed according to the corresponding candidate chemical treatment sequence, and the control reaction slurry was output.

[0008] In a preferred embodiment, S3 includes: S3-1. Perform physical solid-liquid separation on each control reaction slurry and record the pre-filtration pressure and post-filtration pressure at a fixed sampling period during the physical solid-liquid separation process to obtain the pressure difference time series. At the same time, output the control solid phase and control liquid phase. S3-2. Calculate the pressure difference sequence for the pressure difference time series based on adjacent sampling points, and obtain the solid-liquid separation pressure difference growth rate by calculating the arithmetic mean of the pressure difference sequence. Also, measure the residual total phosphorus concentration and residual total fluorine concentration of the control liquid phase to obtain the residual index pair.

[0009] In a preferred embodiment, S3 further includes: S3-3. Perform a single wash on the control solid phase with the solid phase volume equal to the washing water volume and collect the washing liquid. Measure the total phosphorus concentration and total fluoride concentration of the washing liquid to obtain the washing loss index pair. Then, structurally combine the solid-liquid separation pressure difference growth rate, residual index pair, and washing loss index pair to generate a control index set.

[0010] In a preferred embodiment, S4 includes: S4-1. For each index in the control index set corresponding to each candidate chemical treatment sequence, perform linear normalization according to the maximum and minimum values ​​among the candidate chemical treatment sequences to obtain the normalized index set corresponding to each candidate chemical treatment sequence. S4-2. Calculate the arithmetic mean of the normalized indices in each set of normalized indices to obtain the comprehensive score, and select the candidate chemical treatment sequence with the smallest comprehensive score as the target chemical treatment sequence. S4-3. The target chemical treatment sequence is structurally combined with the first pH point, the second pH point, the first calcium salt dosage, the second calcium salt dosage, and the order of calcium salt addition to generate the target operating condition parameter set.

[0011] In a preferred embodiment, S5 includes: S5-1. Based on the target operating condition parameter set, the high-concentration phosphorus and fluoride-containing wastewater is adjusted to the first pH point and the first calcium salt dosage is added. Then, it is adjusted to the second pH point and the second calcium salt dosage is added to obtain the reaction slurry. S5-2. Perform physical solid-liquid separation on the reaction slurry to obtain resource-based solid products and treated effluent, and measure the total phosphorus and total fluoride concentrations of the treated effluent and the total phosphorus and total fluoride concentrations of the washing liquid of resource-based solid products to obtain effluent indicators and solid indicators. S5-3. Write the effluent indicators and solid phase indicators into the corresponding influent dataset entries to form an operation result record, which is used to provide data input for the generation of candidate chemical treatment sequences and comprehensive score calculation for subsequent batches.

[0012] The technical effects and advantages of this invention are as follows: Candidate chemical treatment sequences were generated through parallel control channels, and the sequence was selected by a joint score of solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, and washing loss. This causally suppressed the blockage and fluctuation of resource products caused by phosphorus and fluoride mixed precipitation, thereby relatively reducing the risk of water pollution. By constructing an influent dataset through online sampling and removing outliers by calculating the median and median absolute deviation of the measurement sequences, and then outputting representative values ​​as input for subsequent calculations, the impact of batch fluctuations and occasional measurement anomalies on titration point and dosage decisions can be relatively reduced. By recording the acid-base response sequence and using adjacent differences and second-order differences to determine the first and second acid-base points, the key acid-base range can be relatively stably locked without relying on manual experience thresholds, providing a consistent basis for determining the order of processing. By calculating the dosage of the first and second calcium salts according to stoichiometry, and constructing candidate chemical treatment sequences with only different addition orders for comparison, the co-precipitation of phosphorus and fluorine due to inappropriate order can be relatively reduced, and the controllability of separation and resource utilization pathways can be improved. By performing solid-liquid separation on the control reaction slurry and quantifying the pressure difference growth rate, and by jointly characterizing the total phosphorus concentration and total fluoride concentration of the liquid residue and the solid washing liquid, it is possible to simultaneously consider operational sustainability, effluent control effect and solid resource utilization availability. By writing back the effluent and solid phase indicators to the corresponding influent dataset entries to form an operational result record, the generation of candidate chemical treatment sequences and comprehensive scoring for subsequent batches can reuse historical results for calibration, thereby relatively improving the stability and traceability under continuous operation of multiple batches. Attached Figure Description

[0013] Figure 1 This is a technical roadmap for the present invention.

[0014] Figure 2 This is a flowchart of the method steps of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Refer to the instruction manual appendix Figure 1-2 The present invention discloses a method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater, comprising: S1. Online sampling of the high-concentration phosphorus and fluoride wastewater to be treated is performed to measure the total phosphorus concentration, total fluoride concentration, conductivity and initial pH. Based on the measurement results, an influent dataset is generated. In S1, this embodiment is used to generate a verifiable influent dataset through an online sampling cycle before the high-concentration phosphorus and fluoride-containing wastewater enters the subsequent parallel control channel and candidate chemical treatment sequence. This ensures that the subsequent determination of the first and second pH points, as well as the calculation of the first and second calcium salt dosages, are all based on the same data input, thereby avoiding the amplification of single-point measurement fluctuations into pH point misjudgments or dosage deviations, which could further lead to abnormal increases in solid-liquid separation pressure differences. This implementation process includes the following steps: The purpose of S1-1 is to continuously sample at fixed time intervals to form an initial sequence set of influent, so that fluctuations within an online sampling cycle can be recorded in sequence and used for subsequent robust statistical elimination of occasional anomalies. Inputs include the start and end times of sampling for one online sampling cycle, the fixed time interval, and high-concentration phosphorus and fluoride-containing wastewater at the same sampling point. The processing steps include: the online sampling device extracts a wastewater sample at each sampling time, sequentially sending the wastewater sample to the online total phosphorus analysis unit, the online total fluoride analysis unit, the conductivity measurement unit, and the pH measurement unit, respectively obtaining the total phosphorus concentration, total fluoride concentration, conductivity, and initial pH value corresponding to that sampling time, and appending the total phosphorus concentration value to the total pH value according to the order of sampling times. The phosphorus concentration sequence, the total fluoride concentration value appended to the total fluoride concentration sequence, the conductivity value appended to the conductivity sequence, and the initial pH value appended to the initial pH sequence are used to form four sequences aligned with the same time index. The output is a raw influent sequence set consisting of the total phosphorus concentration sequence, the total fluoride concentration sequence, the conductivity sequence, and the initial pH sequence, and the raw influent sequence set is written to the sampling period buffer for S1-2 to read. The abnormal or missing data handling includes: when any measurement unit returns a null value, an over-range flag, or a self-test failure flag at a certain sampling time, the measurement value corresponding to that sampling time is recorded as missing and written to the missing data flag, while keeping the valid measurement values ​​of other measurement units from being discarded, so as to ensure the continuity of the sequence time index and that robust statistics can still be performed subsequently. S1-2 is used to convert the raw influent sequence set into representative values ​​that can represent the overall level of the sampling period. Its mechanism is to characterize the center position and dispersion of the sequence using the median and median absolute deviation, and then identify and remove outlier measurement points to suppress the influence of occasional jumps on the representative values. The input is the raw influent sequence set output by S1-1. The processing actions include: taking the total phosphorus concentration sequence as an example, firstly, sort the non-missing measurement points in the sequence by value and take the median to obtain the median of total phosphorus concentration. Then, calculate the absolute difference between each non-missing measurement point and the median of total phosphorus concentration to form an absolute deviation sequence. Take the median of the absolute deviation sequence to obtain the median absolute deviation of total phosphorus concentration. Then, calculate the outlier discrimination metric for each measurement point, which is the difference between the absolute deviation of the measurement point and the median absolute deviation of the total phosphorus concentration. The ratio of deviations is used to identify outliers and remove them when the outlier count is greater than three. The same median calculation, median absolute deviation calculation, and outlier removal are performed on the total fluorine concentration sequence, conductivity sequence, and initial pH sequence, respectively. After removing outliers, the arithmetic mean is calculated for the remaining measurement points of each sequence to obtain representative values ​​for total phosphorus concentration, total fluorine concentration, conductivity, and initial pH. The output consists of four representative values, which are written to the representative value buffer for S1-3 to read. Anomaly or missing point handling includes: when the number of remaining measurement points after removing outliers and missing points of a sequence is insufficient to calculate the arithmetic mean, the median of the sequence is directly used as the corresponding representative value and written to the substitution mark so that subsequent steps can still obtain usable input and trace the source of the representative value. The purpose of S1-3 is to write the representative values ​​into the same influent dataset entry according to a fixed field structure, so that subsequent steps can read consistent data on an entry-by-entry basis and establish a calculation basis for the control channel. The inputs are the representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity, and initial pH output from S1-2. The processing actions include: creating an influent dataset entry corresponding to the current online sampling cycle, writing the representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity, and initial pH into the influent dataset entry in sequence, and appending the influent dataset entry to form the updated influent dataset result. The output is an influent dataset containing the newly added influent dataset entry, and the influent dataset entry can be read by the entry index in subsequent S2. Anomaly or missing data handling includes: when any representative value has a missing or substitution marker, the corresponding marker is written into the quality marker field of the influent dataset entry, and the measurement item name corresponding to the missing marker is written into the missing field list to ensure that data quality can be identified and audit evidence is retained when calculating the first pH point, the second pH point, and the calcium salt dosage. In practical applications: The online sampling device continuously samples the inlet water pipeline at fixed time intervals to obtain the total phosphorus concentration sequence, total fluoride concentration sequence, conductivity sequence, and initial pH sequence. When the online total phosphorus analysis unit briefly exceeds its range and returns a missing value, that moment is recorded as missing in the total phosphorus concentration sequence, while other sequences retain valid values. Subsequently, in S1-2, sensor jump points are removed from each sequence based on the median and median absolute deviation, and representative values ​​are calculated. If there are insufficient usable points for a sequence, the median is used as the representative value and a replacement mark is written. Finally, in S1-3, the representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity, and initial pH are written into the same inlet water dataset entry and a quality mark is recorded. This allows subsequent parallel control channels to perform acid-base titration point determination and calcium salt dosage calculation according to the same standard after reading the inlet water dataset entry, thereby reducing the risk of misjudgment of pH points, calcium salt dosage deviation, and abnormal increase in solid-liquid separation pressure difference caused by occasional measurement anomalies.

[0017] S2. Based on the influent dataset, sample water is obtained by diverting the sample water, and acid-base titration is performed on the sample water in at least two parallel control channels to determine the first pH point and the second pH point, thereby generating at least two candidate chemical treatment sequences. The candidate chemical treatment sequences include calcium salt addition at the first pH point and the second pH point, respectively, with the addition amount calculated from the total phosphorus concentration and the total fluoride concentration, and outputting the control reaction slurry. In S2, this embodiment is used to obtain sample water from high-concentration phosphorus and fluoride-containing wastewater after the influent dataset has been generated. Acid-base titration points are determined and candidate chemical treatment sequences are constructed through at least two parallel control channels. This allows for comparable evaluation of subsequent control solid-liquid separation loads and residual indicators at the same titration point, thus providing a verifiable control reaction slurry input for selecting the target chemical treatment sequence. The implementation process includes the following steps: The purpose of S2-1 is to complete acid-base titration and form an acid-base response sequence within the constraints of the device's capacity boundary. Its mechanism involves driving a gradual change in acidity / base using the minimum controllable dosing volume and using the acid-base measurement resolution as a termination criterion to suppress ineffective dosing and over-titering. The inputs include the influent dataset, sample water obtained from the diversion of high-concentration phosphorus- and fluoride-containing wastewater corresponding to the influent dataset, the number of parallel control channels, the acid and alkali solutions, and the dosing device parameters. The minimum controllable dosing volume is taken from the nominal minimum step volume or minimum pulse output volume of the dosing device, and the acid-base measurement resolution is taken from the nominal resolution of the acid-base measurement unit or the resolution recorded in the field calibration. The processing steps include: distributing the sample water in equal volumes into the titration containers of at least two parallel control channels; initializing the acid-base response sequence index for each parallel control channel and recording the initial acid-base value; and then selecting the acid or alkali solution based on the direction of acid-base adjustment. The acid or alkali solution is added to the titration container in increments of the minimum controllable volume. After each addition, the solution is mixed, and the pH value is read after mixing. This pH value is written into the pH response sequence in increment order. Termination determination includes: calculating the pH difference between two adjacent increments; when the pH difference of several consecutive increments is not greater than the pH measurement resolution, the titration is terminated. The output is the pH response sequence corresponding to each parallel control channel, and the pH response sequence is written into the control channel titration buffer for S2-2 to read. Abnormal or missing value handling includes: when the pH measurement unit returns a null value, drift alarm, or over-range flag, the pH measurement value is read again. If it is still abnormal, the pH measurement value corresponding to the increment is recorded as missing and written into the missing value flag. At the same time, the next increment continues while maintaining the continuous increment index, so that subsequent differential calculations can identify and avoid missing points. S2-2 is used to determine the first and second pH points from the pH response sequence. Its mechanism is to use the difference sequence to characterize the abrupt changes in pH, and to lock the candidate indices with the most significant changes by sorting them by the absolute value of the second-order difference. Then, it selects two points from the candidate indices to form the target titration point set by the pH span maximization rule. The input is the pH response sequence output by S2-1. The processing actions include: calculating the adjacent difference sequences in the pH response sequence in increment order, where each item of the adjacent difference sequence is the difference obtained by subtracting the pH values ​​corresponding to two adjacent increments; calculating the second-order difference sequence based on the adjacent difference sequences, where each item of the second-order difference sequence is the difference obtained by subtracting two adjacent items in the adjacent difference sequence; then taking the absolute value of the non-missing items in the second-order difference sequence and sorting them by absolute value from largest to smallest to obtain the candidate index set, where each index in the candidate index set corresponds to an increment position in the pH response sequence. Within the candidate index set, a point selection rule is executed: enumerate any two candidate indices and calculate the absolute value of the difference between their corresponding pH values. Select the two candidate indices with the largest absolute difference as the indices corresponding to the first and second pH points, and determine the pH values ​​corresponding to these two indices as the first and second pH points, respectively, thereby outputting the target titration point set. The output quantity is the target titration point set and is written to the titration point cache for S2-3 to read. Anomaly or missing data handling includes: when consecutive missing data in the second-order difference sequence causes the candidate index set to be empty, the index corresponding to the maximum pH value and the index corresponding to the minimum pH value of the pH response sequence are used as candidate index pairs, and the corresponding first and second pH points are output. At the same time, a replacement marker is written so that a traceability basis can be retained during subsequent comprehensive scoring. The purpose of S2-3 is to generate comparable candidate chemical treatment sequences and output control reaction slurry under the constraints of the target titration point set. Its mechanism involves calculating the dosage of the first and second calcium salts based on the stoichiometric relationship between total phosphorus and total fluoride concentrations, then constructing at least two parallel control schemes based on the sequential differences of the candidate chemical treatment sequences, and actually executing them to produce control reaction slurry. The inputs are the target titration point set, the total phosphorus and total fluoride concentrations in the influent dataset, the sample water volume, and the repeatedly measured total phosphorus and total fluoride concentrations in the sample water in the parallel control channel. The processing actions include: The arithmetic mean of total phosphorus concentration and the arithmetic mean of total fluoride concentration were obtained by calculating the arithmetic mean of total phosphorus concentration and the arithmetic mean of total fluoride concentration, respectively. The total phosphorus concentration and total fluoride concentration in the influent dataset were replaced with the arithmetic mean of total phosphorus concentration and total fluoride concentration as inputs for dosage calculation. Subsequently, the dosages of the first calcium salt and the second calcium salt were calculated according to stoichiometric relationships. The dosage of the first calcium salt was used to meet the stoichiometric requirements for the formation of calcium fluoride by fluoride and calcium ions, and the dosage of the second calcium salt was used to meet the stoichiometric requirements for the formation of phosphorus-containing calcium salt by phosphate and calcium ions. During the calculation, the concentration input and sample water volume were converted into corresponding mass and then converted into the required mass of calcium ions according to the stoichiometric coefficient. Finally, the effective calcium content of the selected calcium salt reagent was used to calculate the calcium salt dosage. After obtaining the first calcium salt dosage and the second calcium salt dosage, at least two candidate chemical treatment sequences are generated. One of the candidate chemical treatment sequences is to first perform the first calcium salt dosage at the first pH point and then perform the second calcium salt dosage at the second pH point. The other candidate chemical treatment sequence is to first perform the second calcium salt dosage at the first pH point and then perform the first calcium salt dosage at the second pH point. In each parallel control channel, acid-base adjustment and calcium salt addition are performed according to the corresponding candidate chemical treatment sequence. Specifically, after adjusting the pH of the sample water to the first pH point, the corresponding calcium salt is added and mixed evenly. Then, after adjusting the pH of the system to the second pH point, another calcium salt is added and mixed evenly to obtain the control reaction slurry. The output volume is the control reaction slurry corresponding to each candidate chemical treatment sequence, and the control reaction slurry is marked as a control object corresponding one-to-one with the candidate chemical treatment sequence for S3 reading. Abnormal or missing handling includes: When repeated measurements of total phosphorus concentration or total fluorine concentration have missing points that prevent the calculation of the arithmetic mean, the arithmetic mean of the available measured values ​​is calculated instead and a missing value is marked. When the pH measurement value fluctuates beyond the pH measurement resolution during pH adjustment, making it impossible to stably reach the target titration point, an equivalent dilution compensation method with a volume smaller than the minimum controllable dosage is adopted or the mixing time is extended to eliminate hysteresis before reading the pH measurement value again. Calcium salt is added only after the target titration point determination condition is met, to ensure that the candidate chemical treatment sequence can be completely executed under feasible device conditions. In practical applications: The treatment station determines, based on the influent dataset, that it needs to divert high-concentration phosphorus and fluoride wastewater to obtain sample water and starts two parallel control channels. In each parallel control channel, acid or alkali solution is added sequentially using the minimum controllable dosing volume of the dosing device, and the acid-base response sequence is recorded. When the acid-base change enters the stable range within the measurement resolution, the titration is terminated and the acid-base response sequence is output. The system calculates the adjacent difference sequence and the second difference sequence from the acid-base response sequence and selects the first and second acid-base points to form the target titration point set. Then, the arithmetic mean of the total phosphorus concentration and total fluoride concentration is repeatedly measured in the parallel control channels. As input for dosage calculation, the dosage of the first and second calcium salts is calculated according to stoichiometry, generating two candidate chemical treatment sequences. Finally, in two parallel control channels, acid-base adjustment and calcium salt addition are completed according to the corresponding candidate chemical treatment sequences to obtain control reaction slurry. This allows the subsequent comparative evaluation of solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, and washing liquid total phosphorus concentration and washing liquid total fluoride concentration to be established on the same titration point and dosage caliber. This facilitates the stable selection of the treatment sequence suitable for the current batch fluctuation conditions and reduces the operational uncertainty in water pollution control and treatment.

[0018] S3. Perform physical solid-liquid separation on the control reaction slurry to obtain the control solid phase and control liquid phase, and measure the solid-liquid separation pressure difference growth rate, the residual total phosphorus concentration and residual total fluoride concentration of the control liquid phase, and the total phosphorus concentration and total fluoride concentration of the control solid phase washing liquid to generate a control index set. This embodiment, based on the obtained control reaction slurry, uses the load characterization of the physical solid-liquid separation process, the characterization of the liquid phase residue after separation, and the characterization of the solid phase washing loss in the control to form a set of control indicators that can be directly used for the comprehensive evaluation of candidate chemical treatment sequences. This ensures that the selection of subsequent target chemical treatment sequences not only considers the residual total phosphorus and residual total fluoride concentrations on the effluent side, but also simultaneously considers the separation operability and solid phase resource utilization availability reflected by the solid-liquid separation pressure difference growth rate and the total phosphorus and total fluoride concentrations in the washing liquid. The implementation process includes the following steps: The purpose of S3-1 is to perform physical solid-liquid separation on each control reaction slurry and generate a calculable pressure difference time series. Its mechanism involves obtaining raw observations of the load change over time during the separation process by synchronously recording the pre-filtration and post-filtration pressures, thus providing verifiable input for calculating the pressure difference growth rate of the solid-liquid separation. The inputs are the control reaction slurry output from each parallel control channel, the physical solid-liquid separation device, and a fixed sampling period. The fixed sampling period is taken from the sampling configuration parameters of the physical solid-liquid separation device or the sampling period configuration of the field control system. The processing actions include: sending each sample of control reaction slurry into the physical solid-liquid separation device and initiating solid-liquid separation; during the solid-liquid separation, the pressure sensor collects the pre-filtration and post-filtration pressures at a fixed sampling period; writing the pre-filtration and post-filtration pressures at each sampling moment into a pressure record sequence using the same time index; and calculating the pressure difference at each sampling moment. The pressure difference is calculated by subtracting the pressure after filtration from the pressure before filtration, and then appended to the pressure difference time series in time index order. After solid-liquid separation, the control solid phase and control liquid phase are collected and written to the sample container identifier of the corresponding channel to maintain a one-to-one correspondence with the candidate chemical treatment sequence. The output is the pressure difference time series, the control solid phase, and the control liquid phase. The pressure difference time series is written to the separation load buffer for S3-2 to read, while the control liquid phase is written to the liquid phase detection buffer and the control solid phase is written to the solid phase washing buffer for subsequent steps to read. Abnormal or missing handling includes: when the pressure before filtration or the pressure after filtration at any sampling time has a null value, exceeds the range, or has a self-test failure mark, the pressure difference calculation at that sampling time is abandoned and a missing mark is written to the pressure difference time series at that sampling time. At the same time, the recording of subsequent sampling times continues to ensure that the time index of the pressure difference time series is continuous and that subsequent differential calculations can avoid missing points. S3-2 is used to calculate the solid-liquid separation pressure difference growth rate from the pressure difference time series and obtain the residual index pairs of the control liquid phase. Its mechanism involves characterizing the incremental trend of pressure difference over time using the pressure difference difference between adjacent sampling points, and using the residual total phosphorus concentration and residual total fluorine concentration to characterize the separation effect of the candidate chemical treatment sequence on the liquid phase side. The input is the pressure difference time series output from S3-1 and the corresponding control liquid phase. The processing includes: subtracting two adjacent non-missing pressure difference values ​​in the pressure difference time series to obtain the pressure difference difference series; each term in the pressure difference difference series corresponds to the pressure difference increment at adjacent sampling times; then, the arithmetic mean of all non-missing terms in the pressure difference difference series is calculated to obtain the solid-liquid separation pressure difference growth rate; simultaneously, the control liquid phase is sent to the online total phosphorus analysis unit and the total... The online fluorine analysis unit measures the residual total phosphorus concentration and residual total fluorine concentration respectively, and combines the residual total phosphorus concentration and residual total fluorine concentration in a structured way to obtain residual index pairs; the output is the solid-liquid separation pressure difference growth rate and residual index pairs, and writes them into the control channel index cache for S3-3 to read; the abnormal or missing handling includes: when the number of non-missing sampling points in the pressure difference time series that can be used to calculate the pressure difference is insufficient to form a pressure difference series, the solid-liquid separation pressure difference growth rate is recorded as missing and written into the missing marker, while the pressure difference time series is retained for traceability; when the residual total phosphorus concentration or residual total fluorine concentration measurement returns a null value or an over-range marker, the sampling measurement is repeated once, and if it is still abnormal, the corresponding residual index is recorded as missing and written into the missing marker; The purpose of S3-3 is to obtain the washing loss index pairs of the control solid phase and generate a control index set. Its mechanism involves quantitatively washing the control solid phase to transfer easily soluble or easily desorbed phosphorus and fluoride-related components to the washing liquid, and then measuring the total phosphorus and total fluoride concentrations of the washing liquid to characterize the potential phosphorus and fluoride loss levels during solid phase resource utilization. The input quantities are the control solid phase and washing water output from S3-1. The processing steps include: measuring the volume of the control solid phase and using it as the basis for determining the washing water volume; adding washing water to the control solid phase in an equal manner to form a washing mixture; subsequently performing solid-liquid separation on the washing mixture and collecting the washing liquid; sending the washing liquid to the online total phosphorus analysis unit and the online total fluoride analysis unit to measure the total phosphorus and total fluoride concentrations of the washing liquid, and then comparing the total phosphorus concentration of the washing liquid with the total fluoride concentration of the solid phase. The fluorine concentration is structured to obtain the washing loss index pair; after obtaining the washing loss index pair, the solid-liquid separation pressure difference growth rate, residual index pair and washing loss index pair are structured to generate the control index set according to the fixed field order, and the control index set is bound to the corresponding candidate chemical treatment sequence identifier and written into the control index set storage area for S4 to read; the output is the control index set; the abnormal or missing handling includes: when the volume of the control solid phase cannot be measured, the solid phase volume is converted by the mass of the control solid phase combined with the pre-measured apparent density of the solid phase and written into the conversion mark; when the washing liquid measurement has a null value or an over-range mark, the measurement is repeated once. If it is still abnormal, the corresponding washing loss index is marked as missing and written into the missing mark. At the same time, the control index set is still generated and the missing item name is recorded in the mass mark field to ensure that the subsequent comprehensive scoring can be executed according to the missing handling rules; In practical applications: After the control reaction slurry output from the parallel control channels enters the physical solid-liquid separation device, the control system records the pre-filtration pressure and post-filtration pressure at a fixed sampling period and calculates the pressure difference time series. At the same time, the control solid phase and control liquid phase are collected. Subsequently, the system calculates the pressure difference difference series from the pressure difference time series and calculates the arithmetic mean to obtain the solid-liquid separation pressure difference growth rate. The residual total phosphorus concentration and residual total fluoride concentration of the control liquid phase are measured to form a residual index pair. Then, the control solid phase is washed once with the solid phase volume equal to the washing water volume, and the total phosphorus concentration and total fluoride concentration of the washing liquid are measured to form a washing loss index pair. Finally, the solid-liquid separation pressure difference growth rate, residual index pair, and washing loss index pair are structurally combined to generate a control index set and written into the control index set storage area. This allows subsequent steps to perform a comparable comprehensive score on candidate chemical treatment sequences based on the control index set. Thus, when selecting a target chemical treatment sequence, the operability of solid-liquid separation, the control effect of liquid phase residue, and the availability of solid phase resource utilization are considered simultaneously, reducing the risk of operational instability and water pollution accumulation caused by abnormal separation load or excessive washing loss.

[0019] S4. Calculate the comprehensive score of each candidate chemical treatment sequence based on the control index set and select the candidate chemical treatment sequence with the smallest comprehensive score as the target chemical treatment sequence, and generate the target operating condition parameter set at the same time. This embodiment is used to unify control indicators of different dimensions to a comparable scale, based on the existing control indicator set and the clear one-to-one correspondence between candidate chemical treatment sequences and these indicators. This allows for the calculation of a comprehensive score and the determination of the target chemical treatment sequence. Simultaneously, the key parameters of the target chemical treatment sequence are structured and solidified into a target operating condition parameter set. This ensures that subsequent acid-base adjustments and calcium salt additions based on the target operating condition parameter set can directly reuse the conclusions of this control evaluation and maintain parameter consistency. The implementation process includes the following steps: The purpose of S4-1 is to perform linear normalization on the control index set corresponding to each candidate chemical treatment sequence, so that the solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, washing liquid total phosphorus concentration, and washing liquid total fluoride concentration can participate in the comprehensive scoring on the same scale. Its working mechanism is to determine the normalization mapping interval by using the maximum and minimum values ​​of the corresponding indicators among the candidate chemical treatment sequences and map the indicator values ​​to dimensionless values. The input is the control index set corresponding to each candidate chemical treatment sequence, which includes at least the solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, washing liquid total phosphorus concentration, and washing liquid total fluoride concentration. The processing actions include: establishing an index value set across candidate chemical treatment sequences for each type of indicator, for example, aggregating the solid-liquid separation pressure difference growth rates of each candidate chemical treatment sequence into a pressure difference growth rate set, and aggregating the residual total phosphorus concentrations of each candidate chemical treatment sequence into a residual total phosphorus concentration set, and calculating the set for each index value set. The minimum and maximum values ​​of the combined values ​​are calculated. Then, linear normalization is performed on each index of each candidate chemical treatment sequence. When the maximum and minimum values ​​are not equal, the minimum value is subtracted from the index value of the candidate chemical treatment sequence and divided by the difference between the maximum and minimum values ​​to obtain the normalized index value. When the maximum and minimum values ​​are equal, the normalized index value of the index of the candidate chemical treatment sequence is set to zero to avoid division by zero and to ensure that the index does not introduce discrimination in this round of comparison. The output is the normalized index set corresponding to each candidate chemical treatment sequence, and the normalized index set is bound to the candidate chemical treatment sequence identifier and written into the normalized index set storage area for S4-2 to read. The abnormal or missing handling includes: when an index of a candidate chemical treatment sequence is missing, the normalized index value of the index in the candidate chemical treatment sequence is set to one, and the missing index name is recorded in the quality mark field of the candidate chemical treatment sequence, so that the missing index is reflected in the comprehensive score in an unfavorable way and is easy to trace. S4-2 is used to calculate a comprehensive score based on a normalized index set and select target chemical treatment sequences. Its mechanism involves aggregating the normalized results of multiple indices into a single score using an arithmetic mean, and using the lowest score as the selection criterion to ensure a verifiable trade-off between solid-liquid separation operability, liquid phase residue control, and solid phase washing loss. The input is the normalized index set corresponding to each candidate chemical treatment sequence output by S4-1. The processing steps include: for each candidate chemical treatment sequence, reading the normalized solid-liquid separation pressure difference growth rate, normalized residual total phosphorus concentration, normalized residual total fluoride concentration, normalized washing liquid total phosphorus concentration, and normalized washing liquid total fluoride concentration from its normalized index set; summing each of these normalized indices and dividing by the number of normalized indices to obtain the comprehensive score of the candidate chemical treatment sequence; then comparing the comprehensive scores among all candidate chemical treatment sequences. The candidate chemical treatment sequence with the lowest comprehensive score is selected as the target chemical treatment sequence. When multiple candidate chemical treatment sequences have the same comprehensive score and are all the lowest, the candidate chemical treatment sequence with the smaller solid-liquid separation pressure difference growth rate is selected first to reduce the risk of subsequent operating load. If the solid-liquid separation pressure difference growth rate is still the same, the candidate chemical treatment sequence with the smaller sum of residual total phosphorus concentration and residual total fluoride concentration is selected first to strengthen the control on the effluent side. The output is the target chemical treatment sequence and its comprehensive score, and the target chemical treatment sequence identifier is written into the target sequence record for S4-3 to read. Abnormal or missing handling includes: when all candidate chemical treatment sequences have missing indicators, resulting in the comprehensive score including missing penalty, the target chemical treatment sequence is still selected according to the above comparison rules, and the missing penalty trigger mark is written into the target sequence record to indicate that a control channel can be added or retested later. The purpose of S4-3 is to solidify the key operating parameters corresponding to the target chemical treatment sequence into a target operating parameter set. Its mechanism involves binding the first pH point, second pH point, first calcium salt dosage, second calcium salt dosage, and the order of calcium salt addition to the same parameter object in a structured field format. This allows subsequent execution steps to directly read the parameters by field and maintain consistency with the control evaluation. The input is the target chemical treatment sequence output by S4-2, along with the target titration point set associated with this sequence, and the first and second calcium salt dosages. The processing actions include: reading the corresponding first and second pH points from the target chemical treatment sequence; reading the first and second calcium salt dosages from the dosage record bound to the target chemical treatment sequence; and... The processing sequence reads the order of calcium salt addition, then creates a target operating condition parameter set and writes the first pH point, second pH point, first calcium salt addition amount, second calcium salt addition amount, and calcium salt addition order into a fixed field order. Simultaneously, it associates the target operating condition parameter set with the influent dataset entry index and the target chemical treatment sequence identifier, enabling subsequent tracing of the selection results based on the same influent dataset entry. The output is the target operating condition parameter set, written to the target operating condition parameter set storage area for S5 reading. Anomaly or missing data handling includes: when any parameter field associated with the target chemical treatment sequence is missing or has a substitution marker, the corresponding marker is copied and written to the quality marker field of the target operating condition parameter set, and a missing field list is written to the missing field list to ensure risk identification and retain audit evidence during subsequent execution. In practical applications: After obtaining the control index sets corresponding to two or more candidate chemical treatment sequences, the system first calculates the maximum and minimum values ​​across the candidate chemical treatment sequences for the solid-liquid separation pressure difference growth rate, residual total phosphorus concentration, residual total fluoride concentration, total phosphorus concentration of the washing liquid, and total fluoride concentration of the washing liquid, and performs linear normalization to obtain the normalized index set corresponding to each candidate chemical treatment sequence. Then, the arithmetic mean of the normalized indexes for each candidate chemical treatment sequence is taken to obtain a comprehensive score, and the candidate chemical treatment sequence with the smallest comprehensive score is selected as the target chemical treatment sequence. If scores are the same, the solid-liquid separation pressure difference growth rate is used as the target chemical treatment sequence. The decision is then made based on the rule that the sum of the residual total phosphorus concentration and the residual total fluoride concentration is smaller. Finally, the first pH point, the second pH point, the first calcium salt dosage, the second calcium salt dosage, and the order of calcium salt addition corresponding to the target chemical treatment sequence are written into the same target operating condition parameter set and associated with the entries in this influent dataset. This allows the target operating condition parameter set to be directly called when performing acid-base adjustment and calcium salt addition on high-concentration phosphorus and fluoride wastewater in the future, and the results of this comparative selection can be stably reproduced. This reduces the fluctuation of solid-liquid separation load and the accumulation of water pollution risk caused by inconsistent operating condition selection during water pollution control and treatment.

[0020] S5. According to the target operating condition parameter set, acid-base adjustment and calcium salt addition are performed on high-concentration phosphorus and fluoride wastewater according to the target chemical treatment sequence to generate reaction slurry. Physical solid-liquid separation is performed on the reaction slurry to obtain resource-based solid products and treated effluent, thereby reducing water pollution risk and achieving water pollution control and treatment. This embodiment, under the premise that the target operating condition parameter set has been generated, performs acid-base adjustment and calcium salt addition on high-concentration phosphorus and fluoride-containing wastewater according to the target chemical treatment sequence to form a reaction slurry. Then, through physical solid-liquid separation, resource-based solid products and treated effluent are obtained. Simultaneously, the treatment results are written back to the corresponding influent dataset entries in the form of effluent indicators and solid indicators, so that subsequent batches can reuse historical operation results and generate candidate chemical treatment sequences and calculate comprehensive scores under the same caliber, thereby reducing operating condition drift and water pollution risk accumulation in the process of water pollution control and treatment. The implementation process includes the following steps: The purpose of S5-1 is to achieve two-stage pH control and two-stage calcium salt addition in a closed loop according to the target operating condition parameter set, thereby forming a reaction slurry that meets the target chemical treatment sequence within the same reaction system. Its mechanism involves using the first and second pH points as addition trigger conditions and the first and second calcium salt addition amounts as addition control amounts to ensure that the reaction conditions remain consistent with the control selection. The inputs include the target operating condition parameter set, high-concentration phosphorus and fluoride-containing wastewater, acid solution, alkali solution, calcium salt reagent, pH measurement unit, and dosing device. The processing actions include: reading the first pH value from the target operating condition parameter set... The process involves introducing high-concentration phosphorus and fluoride-containing wastewater into a reaction vessel and initiating stirring and mixing. The process then proceeds to the first stage of acid-base adjustment. By incrementally adding acid or alkali, the measured pH value within the reaction vessel gradually approaches the first pH point. When the difference between the measured pH value and the first pH point is no greater than the pH measurement resolution, the first pH point is reached, triggering the first calcium salt addition. Following the addition sequence specified by the target operating condition parameter set, the first or second calcium salt dosage is added at that moment, and mixing continues. The second stage of acid-base adjustment is then performed to bring the measured acid-base value close to the second acid-base point. When the difference between the measured acid-base value and the second acid-base point is not greater than the acid-base measurement resolution, it is determined that the second acid-base point has been reached, and the second calcium salt addition is triggered. The remaining calcium salt addition is performed, and mixing continues to obtain the reaction slurry. The output is the reaction slurry, which is written to the reaction slurry container identifier for S5-2 to read. At the same time, the actual measured values ​​of the first and second acid-base points reached this time are written to the operation process record for S5-3 to write back. Abnormal or missing handling includes: when the acid-base measurement unit returns a blank value or a self-test failure mark, the acid-base adjustment is paused and the acid-base measurement value is reread. If the continuous reading is still abnormal, it is switched to the backup acid-base measurement unit and a switching mark is written. When the dosing device reports a dosing deviation alarm, the dosing amount is checked according to the cumulative dosing amount reading of the dosing device, and the check result is written to the operation process record to ensure that the reaction slurry is traceable and can be reused later. S5-2 is used to convert reaction slurry into resource-based solid products and treated effluent, and to form effluent indicators and solid indicators that can be evaluated. Its working mechanism is to obtain two outputs, liquid phase and solid phase, through physical solid-liquid separation, and then measure the liquid phase residue and solid phase washing loss respectively, thereby solidifying the water pollution control and treatment effect and resource availability with quantifiable indicators. The inputs are the reaction slurry output from S5-1, the physical solid-liquid separation device, the washing water, and the online total phosphorus and total fluoride analysis units. The processing steps include: sending the reaction slurry into the physical solid-liquid separation device for solid-liquid separation and collecting the resource-based solid products and treated effluent separately; sending the treated effluent to the online total phosphorus and total fluoride analysis units to measure the total phosphorus and total fluoride concentrations and combining them in a structured manner to obtain the effluent indicators; performing a single washing operation on the resource-based solid products with the solid volume equal to the washing water volume and collecting the washing liquid; and separating the washing liquid into... The total phosphorus and total fluoride concentrations of the washing liquid are measured by the online total phosphorus and online total fluoride analysis units and then structurally combined to obtain solid phase indicators. The output includes resource recovery solid phase products, treated effluent, effluent indicators, and solid phase indicators. The effluent indicators and solid phase indicators are written into the operation result cache for S5-3 to read. Abnormal or missing handling includes: when the measurement of total phosphorus or total fluoride concentration of treated effluent or washing liquid returns a null value or an over-range flag, a new sample is taken and measured. If it is still abnormal, the corresponding indicator is marked as missing and written into the missing flag. At the same time, the sample container identification is retained for subsequent retesting. The purpose of S5-3 is to write back the effluent and solids indicators to the corresponding influent dataset entries to form an operational result record. This allows subsequent batches to use historical results as data input, enhancing the verifiability of candidate chemical treatment sequence generation and comprehensive score calculation. Its mechanism involves binding the representative values ​​of the influent side, the target operating condition parameter set, and the current operational result to the same influent dataset entry index, thus forming an end-to-end closed-loop record. The inputs are the effluent and solids indicators output from S5-2, the operational process record written in S5-1, and the influent dataset entry index corresponding to this treatment. The processing actions include: locating the influent dataset entry corresponding to this treatment, writing the effluent and solids indicators into the operational result field of that influent dataset entry, and writing the measured values ​​of the first and second pH points, as well as the order of calcium salt addition, into the same influent dataset entry. The process fields are used to form the operation result record; then the operation result record is appended to the operation result storage area and associated with the target operating condition parameter set identifier, so that subsequent batches can read the influent side data, selection results and operation results according to the same entry index when generating candidate chemical treatment sequences and calculating comprehensive scores; the output is the influent dataset entry and its operation result record after the write-back is completed; the abnormal or missing handling includes: when the influent dataset entry index does not exist or the match fails, the corresponding entry is retrieved in the influent dataset according to the processing start time and online sampling cycle identifier, and the write-back is performed after the retrieval is successful. At the same time, the retrieval basis is written to the traceability field. When the effluent index or solid phase index has a missing mark, the write-back is still performed and the missing field list is written in the operation result record so that subsequent batches can identify the missing and execute according to the established missing handling rules when calculating the comprehensive score; In practical applications: After reading the target operating condition parameter set, the system introduces high-concentration phosphorus and fluoride-containing wastewater into the reaction vessel and controls the pH to the first pH point through incremental addition of acid or alkali solutions. When the pH measurement resolution is met, the first calcium salt is added and mixed. Then, the pH is controlled to the second pH point, and the second calcium salt is added to obtain the reaction slurry. Subsequently, the reaction slurry enters a physical solid-liquid separation device to separate the resource-based solid products and the treated effluent. The total phosphorus concentration and total fluoride concentration of the treated effluent are measured to form effluent indicators, and the resource-based solid products are separated. After a single washing, the total phosphorus and total fluoride concentrations of the washing liquid are measured to form solid phase indicators. Finally, the system writes the effluent indicators, solid phase indicators, measured values ​​of the first and second pH points, and the order of calcium salt addition back to the corresponding influent dataset entries to form an operational result record. This allows subsequent batches to reuse historical operational results under the same caliber and stably generate candidate chemical treatment sequences and calculate comprehensive scores. As a result, the risk of water pollution is continuously reduced and the controllability and traceability of resource-based solid phase product output are improved in water pollution control and treatment.

[0021] In addition, Figure 1It should be noted that this diagram presents the proposed solution in a parallel table, following the process execution chain and the parallel comparison and selection decision chain. Figure 1 The left side is the process flow diagram (PFD). Figure 1 The right side shows the comparison selection decision process, with the two forming a closed loop using the influent dataset entries, the comparison index set, and the target operating condition parameter set as data hubs. Specifically, the solid arrows on the left indicate the sequential flow of materials or process states within the device. After high-concentration phosphorus and fluoride-containing wastewater enters, S1 online sampling is performed to obtain the influent dataset. Based on the influent dataset, S2 diversion and parallel comparative titration are performed to form a comparison reaction slurry. Then, S3 physical solid-liquid separation is performed to obtain the comparison solid phase and comparison liquid phase, generating the comparison index set. S4 comprehensive scoring determines the target chemical treatment sequence and forms the target operating condition parameter set. Finally, S5 performs acid-base adjustment, calcium salt addition, and solid-liquid separation on the entire wastewater according to the target operating condition parameter set, outputting treated effluent and resource-based solid products. The operation results are recorded and written back to the influent dataset entries for reuse in subsequent batches. The solid arrows on the right indicate the calculation and judgment sequence within the parallel comparison channel. Using the influent dataset entries as input, S2-1 titration is performed to record the acid-base response sequence. S2-2 differential positioning is performed to obtain the first acid-base value. At the first and second pH points, S2-3 is executed to repeatedly measure the average concentration and calculate the dosage of two types of calcium salts using stoichiometry, generating candidate chemical treatment sequences that differ only in their order. Subsequently, S3 is executed to perform solid-liquid separation and index collection to obtain a control index set. In S4, linear normalization and arithmetic mean are performed on the control indexes of each candidate sequence to obtain a comprehensive score. The candidate chemical treatment sequence with the lowest comprehensive score is selected, and the target operating condition parameter set is output. The dashed arrows in the figure are used to express the input-output relationship of data objects between the two links rather than the material flow. That is, the influent dataset entries are output from the left S1 and used as the input for the right control selection. The control index set and comprehensive score selection results formed on the right are fed back to the left S4 to generate the target operating condition parameter set and drive the left S5 full processing. The running results are recorded by writing back and reusing the dashed closed loop to write the effluent index and solid phase index into the corresponding influent dataset entries, so that the generation of candidate chemical treatment sequences and comprehensive score calculation in subsequent batches can obtain historical data support and stably achieve the water pollution control and treatment goals.

[0022] Working principle: This scheme first samples high-concentration phosphorus and fluoride wastewater online to measure total phosphorus concentration, total fluoride concentration, conductivity, and initial pH, forming an influent dataset to ensure consistent data standards for subsequent calculations. Then, sample water is obtained from the same batch of wastewater, and acid or alkali is added sequentially in at least two parallel control channels, recording the pH response sequence. The first and second pH points are determined through differential calculation. The first and second calcium salt dosages are then calculated based on the stoichiometric relationship between total phosphorus concentration, total fluoride concentration, and sample water volume, generating candidate chemical treatment sequences with different addition orders and obtaining a control reaction slurry. Solid-liquid separation is performed on the control reaction slurry, and the pressure differential growth rate, residual total phosphorus and fluoride concentrations on the effluent side, and total phosphorus and fluoride concentrations in the solid phase washing liquid are measured to form a control index set. A comprehensive score is calculated, and the candidate chemical treatment sequence with the lowest comprehensive score is selected as the target chemical treatment sequence, generating a target operating condition parameter set. Finally, according to the target operating condition parameter set, the entire batch of wastewater is subjected to two stages of pH control and two calcium salt additions and solid-liquid separation according to the target chemical treatment sequence to obtain resource-based solid products and treated effluent. The effluent index and solid index are written back to the corresponding influent dataset entries for subsequent batches to continue selection and evaluation, thereby reducing water pollution risk and improving operational stability in water pollution control and treatment. In practical applications, such as at a wastewater treatment plant in an industrial park, where the influent water quality fluctuates daily, the system first samples and builds a database. Then, it uses two control channels to titrate the same batch of sample water and identify two pH points. Based on the total phosphorus and total fluoride concentrations of the batch, it calculates the calcium salt dosage for two separate additions and performs control reactions and solid-liquid separation according to two different addition sequences. The system simultaneously monitors three types of measurable results: whether the separation process becomes clogged (i.e., the pressure difference growth rate), how much phosphorus and fluoride remains in the treated effluent (i.e., residual total phosphorus and fluoride concentrations), and how much phosphorus and fluoride is removed by solid-phase washing (i.e., total phosphorus and fluoride concentrations in the washing liquid). The sequence with the lowest overall score is used as the target chemical treatment sequence for this batch. Subsequently, the entire batch of wastewater is processed in this sequence, and the results are written back. When the next batch arrives, the historical results are directly reused, continuously and stably achieving phosphorus and fluoride separation, purification, and resource utilization.

[0023] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater, characterized in that, include: S1. Online sampling of the high-concentration phosphorus and fluoride wastewater to be treated is performed to measure the total phosphorus concentration, total fluoride concentration, conductivity and initial pH. Based on the measurement results, an influent dataset is generated. S2. Based on the influent dataset, sample water is obtained by diverting the sample water, and acid-base titration is performed on the sample water in at least two parallel control channels to determine the first pH point and the second pH point, thereby generating at least two candidate chemical treatment sequences. The candidate chemical treatment sequences include calcium salt addition at the first pH point and the second pH point, respectively, with the addition amount calculated from the total phosphorus concentration and the total fluoride concentration, and outputting the control reaction slurry. S3. Perform physical solid-liquid separation on the control reaction slurry to obtain the control solid phase and control liquid phase, and measure the solid-liquid separation pressure difference growth rate, the residual total phosphorus concentration and residual total fluoride concentration of the control liquid phase, and the total phosphorus concentration and total fluoride concentration of the control solid phase washing liquid to generate a control index set. S4. Calculate the comprehensive score of each candidate chemical treatment sequence based on the control index set and select the candidate chemical treatment sequence with the smallest comprehensive score as the target chemical treatment sequence, and generate the target operating condition parameter set at the same time. S5. According to the target operating condition parameter set, acid-base adjustment and calcium salt addition are performed on high-concentration phosphorus and fluoride wastewater according to the target chemical treatment sequence to generate reaction slurry. Physical solid-liquid separation is then performed on the reaction slurry to obtain resource-based solid products and treated effluent.

2. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 1, characterized in that: S1 includes: S1-1. Within a single online sampling cycle, high-concentration phosphorus and fluoride-containing wastewater is continuously sampled at fixed time intervals to obtain the total phosphorus concentration sequence, total fluoride concentration sequence, conductivity sequence, and initial pH sequence, and to generate the influent original sequence set. S1-2. Calculate the median and median absolute deviation for each sequence in the original sequence set of influent, and remove the measurement points that deviate from the median by more than three times the median absolute deviation. Then calculate the arithmetic mean of the remaining measurement points and output the representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity and initial pH. S1-3. The representative values ​​of total phosphorus concentration, total fluoride concentration, conductivity and initial pH are structurally combined and written into the same influent dataset entry to obtain the influent dataset.

3. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 2, characterized in that: S2 includes: S2-1. Based on the influent dataset, high-concentration phosphorus and fluoride-containing wastewater is diverted to obtain sample water and distributed to at least two parallel control channels. In each parallel control channel, acid or alkali solution is added to the sample water in increments using the minimum controllable dosing volume of the dosing device as the increment, and the pH value corresponding to each increment is recorded simultaneously to form a pH response sequence. When the pH difference corresponding to each consecutive increment is not greater than the pH measurement resolution, the titration is terminated and the pH response sequence is output. S2-2. Calculate the adjacent difference sequences and the second difference sequence in incremental order for the acid-base response sequence. Sort the candidate index set by the absolute value of the second difference sequence from largest to smallest. Select the two indices that make the corresponding acid-base difference the largest in the candidate index set as the first acid-base point and the second acid-base point to output the target titration point set.

4. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 3, characterized in that: S2 further includes: S2-3. Based on the target titration point set and the total phosphorus concentration, total fluoride concentration and sample water volume in the influent data set, calculate the dosage of the first calcium salt that allows fluoride and calcium ions to form calcium fluoride in stoichiometry and the dosage of the second calcium salt that allows phosphate and calcium ions to form phosphorus-containing calcium salt in stoichiometry. The arithmetic mean of the total phosphorus concentration and the total fluoride concentration of the sample water in the parallel control channel were calculated. The average total phosphorus concentration and the average total fluoride concentration were then substituted into the calculation formulas for the first calcium salt dosage and the second calcium salt dosage to obtain the updated dosage. At least two candidate chemical treatment sequences were generated. The candidate chemical treatment sequences were: first, the first calcium salt was added at the first pH point, and then the second calcium salt was added at the second pH point; and second, the second calcium salt was added at the first pH point, and then the first calcium salt was added at the second pH point. In each parallel control channel, acid-base adjustment and calcium salt addition were performed according to the corresponding candidate chemical treatment sequence, and the control reaction slurry was output.

5. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 4, characterized in that: S3 includes: S3-1. Perform physical solid-liquid separation on each control reaction slurry and record the pre-filtration pressure and post-filtration pressure at a fixed sampling period during the physical solid-liquid separation process to obtain the pressure difference time series. At the same time, output the control solid phase and control liquid phase. S3-2. Calculate the pressure difference sequence for the pressure difference time series based on adjacent sampling points, and obtain the solid-liquid separation pressure difference growth rate by calculating the arithmetic mean of the pressure difference sequence. Also, measure the residual total phosphorus concentration and residual total fluorine concentration of the control liquid phase to obtain the residual index pair.

6. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 5, characterized in that: S3 further includes: S3-3. Perform a single wash on the control solid phase with the solid phase volume equal to the washing water volume and collect the washing liquid. Measure the total phosphorus concentration and total fluoride concentration of the washing liquid to obtain the washing loss index pair. Then, structurally combine the solid-liquid separation pressure difference growth rate, residual index pair, and washing loss index pair to generate a control index set.

7. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 6, characterized in that: S4 includes: S4-1. For each index in the control index set corresponding to each candidate chemical treatment sequence, perform linear normalization according to the maximum and minimum values ​​among the candidate chemical treatment sequences to obtain the normalized index set corresponding to each candidate chemical treatment sequence. S4-2. Calculate the arithmetic mean of the normalized indices in each set of normalized indices to obtain the comprehensive score, and select the candidate chemical treatment sequence with the smallest comprehensive score as the target chemical treatment sequence. S4-3. The target chemical treatment sequence is structurally combined with the first pH point, the second pH point, the first calcium salt dosage, the second calcium salt dosage, and the order of calcium salt addition to generate the target operating condition parameter set.

8. The method for phosphorus and fluoride separation, purification, and resource utilization of high-concentration phosphorus and fluoride-containing wastewater according to claim 7, characterized in that: S5 includes: S5-1. Based on the target operating condition parameter set, the high-concentration phosphorus and fluoride-containing wastewater is adjusted to the first pH point and the first calcium salt dosage is added. Then, it is adjusted to the second pH point and the second calcium salt dosage is added to obtain the reaction slurry. S5-2. Perform physical solid-liquid separation on the reaction slurry to obtain resource-based solid products and treated effluent, and measure the total phosphorus and total fluoride concentrations of the treated effluent and the total phosphorus and total fluoride concentrations of the washing liquid of resource-based solid products to obtain effluent indicators and solid indicators. S5-3. Write the effluent indicators and solid phase indicators into the corresponding influent dataset entries to form an operation result record, which is used to provide data input for the generation of candidate chemical treatment sequences and comprehensive score calculation for subsequent batches.

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