A sewage treatment method and system based on magnetic coagulation separation and magnetic seed recovery

Abstract

The present application belongs to the technical field of sewage treatment, and particularly relates to a sewage treatment method and system based on magnetic coagulation separation and magnetic seed recovery. The method comprises: receiving sewage to be treated, and obtaining pollution load of the sewage to be treated, recovering magnetic seeds, and obtaining quality state of the magnetic seeds; activating the recovered magnetic seeds according to the quality state of the magnetic seeds to form an active magnetic seed bed layer containing multiple bed units and for the sewage to be treated to flow through; performing side flow staged magnetic capture on the bed units to obtain a magnetic spectrum fingerprint; determining unstripped pollution load of each bed unit according to the pollution load and the magnetic spectrum fingerprint; when any unstripped pollution load meets stripping conditions, performing playback verification on historical pollution load and historical magnetic spectrum fingerprint to determine a bed unit to be stripped; demagnetizing and stripping the bed unit to be stripped to obtain a pollution-loaded magnetic seed slurry; determining a regeneration grade according to the pollution-loaded magnetic seed slurry, and processing the pollution-loaded magnetic seed slurry according to the regeneration grade to obtain regenerated magnetic seeds and return the regenerated magnetic seeds, and output treated water.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a wastewater treatment method and system based on magnetic coagulation separation and magnetic seed recovery. Background Technology

[0002] Magnetic coagulation separation technology typically involves adding coagulants, flocculants, and magnetic seeds to wastewater. This causes suspended solids, colloidal particles, and some phosphorus-containing pollutants to form magnetic flocs. The magnetic particles then accelerate solid-liquid separation, and the magnetic seeds are recovered through subsequent separation devices. While this method can shorten settling time, in actual operation, most processes still rely on overall mixing, overall settling, or overall recovery. The loading state of the magnetic seeds in the water, the distribution of pollutants within the bed, and the reuse status of the recovered magnetic seeds lack continuous correlation.

[0003] Current treatment methods often rely on influent water quality, effluent turbidity, or settled sludge volume to determine whether to add chemicals, remove sludge, or recover magnetic seeds. This makes it difficult to identify the sufficiency of magnetic seed binding with contaminants in different bed zones, and also to differentiate between the load increase caused by short-term influent shocks and the actual stripping requirements resulting from long-term accumulation within the bed. The magnetic seed recovery stage typically involves uniformly shearing, washing, or reintroducing contaminated magnetic seeds without considering regeneration levels based on seed response, particle size retention, and surface contamination. This can easily lead to over-treatment of usable seeds or the re-entry of ineffective seeds into the treatment bed. These problems result in localized bed overload, magnetic particle leakage, inconsistent regenerated seed quality, and mismatches between reintroduction locations and actual contaminant load requirements, affecting the continuous operation of magnetic coagulation separation and magnetic seed recycling. Summary of the Invention

[0004] This invention provides a wastewater treatment method and system based on magnetic coagulation separation and magnetic seed recovery, which at least solves the problem of how to identify the fouling accumulation state of the bed unit in magnetic coagulation wastewater treatment and re-inject regenerated magnetic seeds according to the magnetic seed regeneration level.

[0005] In a first aspect, the present invention provides a wastewater treatment method based on magnetic coagulation separation and magnetic seed recovery, the method comprising: Receive wastewater to be treated and obtain the pollution load, recovered magnetic seeds and magnetic seed quality status of the wastewater to be treated; The magnetic seeds are activated and recovered according to their quality status, forming an active magnetic seed bed containing multiple bed units through which the wastewater to be treated flows. The sideflow of each bed unit is subjected to graded magnetic capture to obtain magnetic spectral fingerprints that characterize the magnetic response distribution and fouling state of each bed unit. The unstripped contamination load of each bed unit is determined based on the contamination load and magnetic spectral fingerprint. The unstripped contamination load is used to characterize the contamination load that has accumulated in each bed unit and has not yet been released through demagnetization stripping. When any unstripped contamination load meets the stripping conditions, the historical contamination load and historical magnetic spectrum fingerprint are replayed and verified to determine the bed unit to be stripped. The stripping bed unit was demagnetized and stripped to obtain a contaminant-loaded magnetic seed slurry; The regeneration level is determined based on the slurry containing the pollutant magnetic seed, and the slurry is treated according to the regeneration level to obtain regenerated magnetic seeds. The regenerated magnetic seeds are then fed back into the active magnetic seed bed and the treated effluent is output.

[0006] Secondly, the present invention provides a wastewater treatment system based on magnetic coagulation separation and magnetic seed recovery, for implementing a wastewater treatment method based on magnetic coagulation separation and magnetic seed recovery, the system comprising: The acquisition module is used to receive the wastewater to be treated and acquire the pollution load, recovered magnetic seeds, and magnetic seed quality status of the wastewater to be treated. The activation module is used to activate and recover magnetic seeds according to their quality status, forming an active magnetic seed bed containing multiple bed units through which the wastewater to be treated flows. The capture module is used to perform graded magnetic capture of the sideflow of each bed unit to obtain magnetic spectral fingerprints that characterize the magnetic response distribution and fouling state of each bed unit. The load module is used to determine the unstripped contamination load of each bed unit based on the contamination load and magnetic spectral fingerprint. The unstripped contamination load is used to characterize the contamination load that has accumulated in each bed unit and has not yet been released through demagnetization and stripping. The replay module is used to replay and verify the historical pollution load and historical magnetic spectrum fingerprint when any unstripped pollution load meets the stripping conditions, and to determine the bed unit to be stripped. The stripping module is used to demagnetize and strip the bed unit to be stripped, obtaining a contaminant-loaded magnetic seed slurry. The regeneration module is used to determine the regeneration level based on the pollutant-carrying magnetic seed slurry, and to process the pollutant-carrying magnetic seed slurry according to the regeneration level to obtain regenerated magnetic seeds. The regenerated magnetic seeds are then fed back into the active magnetic seed bed and the treated effluent is output.

[0007] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: By obtaining the wastewater pollution load and the quality status of the recovered magnetic seeds, the correlation between the influent load and the reusability of the magnetic seeds was realized, enabling the recovered magnetic seeds to be screened and activated before entering the bed.

[0008] By forming an active magnetic seed bed containing multiple bed units, wastewater can sequentially undergo pollutant interception, formation of pollutant-laden magnetic seeds, and retention of magnetic particles along the bed flow direction.

[0009] By performing graded magnetic capture of the side flow of the bed unit and generating magnetic spectral fingerprints, the magnetic response state of each bed unit can be transformed into a basis for subsequent load judgment.

[0010] By identifying unstripped contamination loads using contamination load and magnetic spectral fingerprinting, it is possible to identify the contamination state that has accumulated but not yet been released within the bed unit.

[0011] By replaying and verifying historical pollution loads and historical magnetic spectrum fingerprints, it is possible to distinguish between short-term fluctuations in influent and actual bed accumulation, and thus determine the bed units to be stripped.

[0012] By treating the polluted magnetic seed slurry according to the regeneration grade and then reintroducing the regenerated magnetic seed, the quality status of the regenerated magnetic seed is matched with the requirements of the bed unit, thereby forming a continuous closed loop of separation, stripping, regeneration and reintroduction. Attached Figure Description

[0013] Figure 1 This is a schematic flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the influent load and magnetic seed quality field structure in an embodiment of the present invention; Figure 3 This is a magnetic spectral fingerprint matrix diagram of the bed unit in an embodiment of the present invention; Figure 4 This is a diagram showing the historical pollution load replay verification and the determination of the area to be stripped in an embodiment of the present invention; Figure 5 This is a diagram showing the relationship between the regeneration level and refeeding of the contaminated magnetic seed in an embodiment of the present invention; Figure 6 This is a block diagram of the module composition of the system of the present invention. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of one or more embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this invention.

[0015] Magnetic coagulation separation and magnetic seed recovery is a water treatment technology that combines coagulation reaction, magnetic particle loading, magnetic field separation, and magnetic seed recycling. The process involves not only the transfer of pollutants from the aqueous phase to the floc phase but also the state changes of the magnetic seeds during pollutant capture, magnetic separation, pollutant release, and regeneration. For continuously operating wastewater treatment systems, the magnetic seeds are not a one-time addition but a circulating medium that needs to maintain capture, separability, and reusability at different treatment stages. Therefore, incorporating wastewater pollution load, the response of magnetic particles within the bed, the accumulation state of pollutants, and the quality of regenerated magnetic seeds into the same treatment chain is crucial for achieving stable and synergistic effects between magnetic coagulation separation and magnetic seed recovery. This invention constructs a wastewater treatment method and system around this treatment chain, consisting of an active magnetic seed bed, magnetic spectral fingerprinting, unstripped pollution load, historical pollution load replay verification, demagnetization stripping, and regeneration-level regeneration.

[0016] like Figure 1 As shown, a wastewater treatment method based on magnetic coagulation separation and magnetic seed recovery includes the following treatment process.

[0017] The wastewater treatment control unit receives wastewater entering the treatment system and simultaneously acquires operational data characterizing the current treatment load. This operational data can come from influent flow meters, turbidity meters, suspended solids meters, total phosphorus meters, pH meters, and temperature meters, or from manual sampling results or the plant's operational database. The pollution load characterizes the treatment pressure exerted by the wastewater on the activated magnetic seed bed during the current time period. It is determined by combining influent flow rate and pollutant concentration, and is used to subsequently determine whether there is contamination accumulation in the bed unit.

[0018] The recovered magnetic seeds are output from the magnetic seed recovery section and enter the testing station via the magnetic seed temporary storage tank. The magnetic seed quality status is used to characterize whether the recovered magnetic seeds can continue to participate in pollutant capture. The testing includes the quantity of recovered magnetic seeds, the retention of magnetic response, particle size distribution, and the degree of surface contamination. The retention of magnetic response can be determined by the capture rate or the amount of residual magnetic particles under fixed magnetic field conditions. The particle size distribution can be obtained by sieving or particle size detection. The degree of surface contamination can be determined by the amount of suspended solids released before and after cleaning, the adhesion of grease, or the observation results of surface coatings. After completing the above input processing, the processing system sends the contamination load and magnetic seed quality status to the magnetic seed activation control unit as the basis for forming an active magnetic seed bed.

[0019] The magnetic seed activation control unit receives the recovered magnetic seeds and their quality status from the previous stage, sorts and surface-treats the recovered magnetic seeds, and then configures the treated magnetic seeds into the bed space through which the wastewater flows. The magnetic seed quality status reflects the ability of the recovered magnetic seeds to continue participating in pollutant capture, and is determined at least by the retention of magnetic response, particle size distribution, surface contamination level, and available quantity. The magnetic seed activation control unit excludes magnetic seeds with insufficient magnetic response, particle size significantly deviating from the process range, or surface contamination that is difficult to clean, and sends the remaining seeds to the surface activation station. The surface activation station, through cleaning, dispersion, and active layer construction, enables the magnetic seed surface to adsorb colloids, phosphates, and fine suspended solids. The activated magnetic seeds are then sent to the bed construction zone, where they are configured into multiple bed units according to the wastewater flow direction, forming an activated magnetic seed bed capable of continuously receiving wastewater and participating in pollutant capture.

[0020] In one embodiment, the activated magnetic seed bed is configured with a first bed unit, a second bed unit, and a third bed unit along the wastewater flow direction. The first bed unit is located on the influent side and mainly receives the initial influent section with a high pollution load, used to intercept suspended solids, colloidal particles, and some phosphorus pollutants in the wastewater. The activated magnetic seeds configured in this area should have high surface activity and good dispersion to prevent pollutants on the influent side from rapidly accumulating in local areas, forming short-circuit or blockage. The magnetic field confinement strength of the first bed unit is determined based on the influent flow velocity, suspended solids concentration, and bed pressure difference. The principle is to maintain stable residence of the activated magnetic seeds within the bed while allowing them to generate moderate micro-movements to increase contact opportunities with pollutants.

[0021] The second bed unit, located downstream of the first bed unit, is designed to allow contaminants entering this area to continue adhering to the surface of the active magnetic seed, forming a contaminant-laden magnetic seed that can be demagnetized, stripped, and regenerated via bypass. The second bed unit is not intended for simple interception, but rather to allow the initially intercepted contaminants to form a relatively stable contaminant-laden structure on the magnetic seed surface. The hydraulic retention time within the second bed unit is determined based on the influent contaminant load and sideflow detection results. When the interception rate of the first bed unit is high, the hydraulic load of the second bed unit can be reduced accordingly, allowing sufficient contact time for the contaminant-laden structure formation process. If the proportion of weakly magnetically responsive particles in the output sideflow of the second bed unit increases, it indicates insufficient binding between the contaminants and the magnetic seed. The control unit can then increase the proportion of active magnetic seeds in this area or adjust the replenishment position of the surface-activated magnetic seeds.

[0022] The third bed unit, located on the effluent side, is used to intercept magnetic particles output from the second bed unit, especially fine magnetic particles that are not fully deposited in the bed, weakly magnetically responsive composite particles, and a small amount of free magnetic seeds. The magnetic seeds configured in the third bed unit are preferentially selected based on larger particle size, more stable magnetic response, and lower surface contamination levels to form an end-of-line protective layer. The operating status of the third bed unit is comprehensively judged by effluent turbidity, magnetic seed leakage, and bed pressure differential. If magnetic seed leakage increases while the influent pollution load does not change significantly, the control unit marks this area as requiring replenishment of strongly magnetically responsive seeds and preferentially allocates subsequently regenerated reusable magnetic seeds to the third bed unit. Through this zoning, wastewater sequentially undergoes pollutant interception, contaminated magnetic seed formation, and magnetic particle retention within the bed, enabling different bed units to undertake different treatment tasks and providing a clear bed location basis for subsequent side-flow magnetic capture and demagnetization stripping.

[0023] In one embodiment, the magnetic seed activation control unit determines the reusable magnetic seeds from the recovered magnetic seeds based on the magnetic seed quality status. The magnetic seed quality status can be composed of magnetic response retention, particle size retention, surface contamination level, and available quantity. Magnetic response retention is used to determine whether the magnetic seeds can still be stably captured under a fixed magnetic field; particle size retention is used to determine whether the magnetic seeds have undergone excessive wear or agglomeration; and surface contamination level is used to determine whether there is grease coating, flocculant residue, or inorganic deposition on the magnetic seed surface. The determination of reusable magnetic seeds does not rely on a single detection item but combines the above detection items with the current bed requirements. When the influent pollution load is high, magnetic seeds with high surface activity and stable particle size distribution are preferentially selected for the first bed unit; when the magnetic seed leakage on the effluent side increases, magnetic seeds with stronger magnetic response are preferentially selected for the third bed unit.

[0024] After the refillable magnetic seeds enter the surface activation station, loose sludge and weakly bound flocs on the surface are first removed by rinsing with clean water or gentle mechanical dispersion. Then, depending on the degree of surface contamination, whether intensive cleaning is necessary is determined. When the surface contamination is low, hydraulic rinsing is sufficient to restore the magnetic seed surface. If organic matter or grease is present, the seeds can enter a separate cleaning branch, with the cleaning wastewater returned to the sludge treatment section or the front-end conditioning section, not entering the effluent channel. The cleaned magnetic seeds then enter the active layer construction station, where a low dose of iron or aluminum salt is added to the magnetic seed slurry. Short-term mixing allows the hydrolysis products to adhere to the magnetic seed surface, forming an active layer capable of adsorbing pollutants. The mixing intensity is constrained by ensuring uniform dispersion of the magnetic seeds without significant wear. The mixing time is set based on the magnetic seed slurry concentration, particle size distribution, and leakage of the magnetic seeds on the effluent side, avoiding excessive shearing that could cause particle size reduction.

[0025] After surface activation, the resulting active magnetic seeds are introduced into the bed configuration station. The bed configuration station allocates active magnetic seeds according to the bed's function, rather than mixing all active magnetic seeds and adding them evenly. The first bed unit receives active magnetic seeds with high surface activity to absorb the influent contaminant load; the second bed unit receives active magnetic seeds with relatively balanced surface activity and magnetic response to form the contaminant-carrying magnetic seeds; the third bed unit receives active magnetic seeds with stable magnetic response and concentrated particle size distribution to reduce the escape of magnetic particles from the effluent side. If a bed unit enters a pending stripping state due to increased contaminant load from unstripped material, the bed configuration station performs demagnetization stripping and replenishment in that area, and then replenishes the corresponding area with regenerated active magnetic seeds that meet the quality requirements. The replenishment amount is determined based on the bed volume that the area can accommodate, the current pressure difference, and the subsequent sideflow magnetic spectrum fingerprint, avoiding excessive replenishment that could increase hydraulic resistance. Through reusable magnetic seed screening, surface activation, and functional configuration, the recovered magnetic seeds are transformed from simple recycled materials into active bed media capable of undertaking the task of zoned capture, and the state of the active magnetic seed bed is transferred to the subsequent side-flow graded magnetic capture stage.

[0026] After the activated magnetic seed bed stabilizes and receives wastewater, the bed monitoring unit draws a small proportion of sideflow from each bed unit and sends it to the staged magnetic capture device. The sideflow characterizes the magnetic response state of pollutants within the bed unit after combining with the activated magnetic seeds and is not used as the effluent discharge path. The staged magnetic capture device is equipped with multiple capture zones with different magnetic field gradients, allowing magnetic particles with varying magnetic response capabilities to be sequentially trapped. The detection and control unit records the capture volume in each capture zone and simultaneously collects residual turbidity, magnetic seed leakage, and bed pressure differential changes after staged capture. The above detection data is compiled into a magnetic spectral fingerprint, which represents the magnetic response distribution and contaminant loading state of the bed unit within the current time period and is transferred to the unstripped contaminant load determination stage.

[0027] In one embodiment, sideflow sampling points are respectively located at the effluent side or local circulation outlet of the first, second, and third bed units. The first bed unit is close to the inlet, and the sideflow is mainly used to determine whether pollutants entering the bed are effectively intercepted by the active magnetic seeds; the second bed unit is located in the pollutant-laden magnetic seed formation area, and the sideflow is mainly used to determine the magnetic response distribution after the pollutants combine with the magnetic seeds; the third bed unit is close to the effluent, and the sideflow is mainly used to determine whether there is a risk of magnetic particle escape. The sampling ratio of each sideflow is determined based on the main flow rate, the stable sampling capability of the detection device, and the pressure difference change of the bed units. If the sampling ratio is too high, it will affect the stability of the main flow channel of the bed; if the sampling ratio is too low, the detection results will not reflect the bed state. The sampling pipeline is equipped with an anti-clogging flushing branch. When the turbidity of the sideflow suddenly increases or the sampling pressure is abnormal, the detection control unit suspends the writing of the current sideflow data and performs pipeline flushing to prevent blockage data from being mistaken for abnormal bed contamination.

[0028] After entering the graded magnetic capture device, the sideflow sequentially passes through a low magnetic field gradient capture zone, a medium magnetic field gradient capture zone, and a high magnetic field gradient capture zone. The low magnetic field gradient capture zone primarily traps larger-sized, magnetically responsive pollutant-laden magnetic seeds; the medium magnetic field gradient capture zone primarily traps moderately bound magnetic composite particles; and the high magnetic field gradient capture zone primarily traps weakly responsive particles and a small amount of free magnetic seeds. The trapping amounts for strong, medium, and weak magnetic responses are determined by the mass, volume concentration, or particle count of the particles trapped in each capture zone, respectively. The specific metering method used depends on the configuration of the on-site monitoring equipment, but the same metering method is maintained within the same operating cycle. Residual turbidity is collected by a turbidity detector at the rear of the high magnetic field gradient capture zone to characterize fine suspended matter or non-magnetic colloids that have not yet been captured by the magnetic field. Magnetic seed leakage is determined by a magnetic particle trapping plate or magnetic particle detector at the rear end to determine whether magnetic seeds have flowed across the bed. The pressure difference is determined by the pressure detection points at the inlet and outlet of the bed unit, and is used to determine whether the pollutant particles have caused local blockage or bed compaction.

[0029] The detection and control unit combines the strong magnetic response capture amount, moderate magnetic response capture amount, weak magnetic response capture amount, residual turbidity, magnetic seed leakage, and pressure difference change obtained from the same bed unit within the same sampling period to form a magnetic spectral fingerprint. The magnetic spectral fingerprint is not a single value, but rather a state record stored according to the bed unit and sampling period, used to illustrate the distribution of pollutants after binding with magnetic seeds within that bed unit. If the proportion of strong magnetic response capture is high and the residual turbidity is low, it indicates that the pollutants mainly exist in a relatively stable pollutant-carrying magnetic seed form; if the weak magnetic response capture amount increases, it indicates that the pollutants are not sufficiently bound to the magnetic seeds or the bed activity is reduced; if the magnetic seed leakage increases, it indicates insufficient retention capacity at the end of the bed or excessive local hydraulic scouring; if the pressure difference change continues to increase, it indicates that there is pollutant accumulation in the bed unit. After completing the above judgments, the magnetic spectral fingerprint, along with the bed unit number and sampling period, enters the unstripped pollution load calculation stage, providing a data basis for determining the location of the bed that needs demagnetization and stripping.

[0030] The load calculation unit receives the pollution load and magnetic spectrum fingerprint generated in the previous stage and establishes operating status records for each bed unit. The pollution load represents the amount of pollutants carried by wastewater when it enters the activated magnetic seed bed, while the magnetic spectrum fingerprint represents the capture and leakage status of magnetic particles within each bed unit. The load calculation unit allocates the pollution load to the corresponding bed units according to the water flow direction, bed zoning, and sampling period to obtain the inflow load. For the same bed unit, the load calculation unit combines the weak magnetic response capture amount, strong magnetic response capture amount, magnetic seed leakage amount, and pressure difference change to determine the load accumulation status. The inflow load and the load accumulation status together form the unstripped pollution load, which serves as the input for subsequent stripping condition judgment and the selection of bed units to be stripped.

[0031] In one embodiment, the pollution load is determined by the influent flow rate, suspended solids concentration, turbidity, total phosphorus concentration, and operating period, representing the intensity of pollutant input into the active magnetic seed bed during the current period. The influent flow rate is obtained from a flow meter on the influent pipeline, while the suspended solids concentration, turbidity, and total phosphorus concentration are obtained from online detectors or sampling results. When a certain detection item is temporarily missing, the load calculation unit can use the most recent valid detection value under the same operating conditions as a temporary substitute, and mark that period as a period to be reviewed, avoiding interruption of bed status judgment due to detection gaps. The temporary data is only used to maintain continuous load calculation; after obtaining valid detection values ​​later, the load entering the period to be reviewed can be updated.

[0032] The incoming load is determined according to the hydraulic distribution relationship of the bed units. This hydraulic distribution relationship can be determined by the influent ratio, bed cross-sectional area, local flow velocity, and valve opening of the bed units, representing the distribution of pollutant input among different bed units. If the active magnetic seed bed adopts a series structure, the first bed unit receives the main incoming load, the second bed unit receives the remaining load after reduction by the first bed unit, and the third bed unit receives the remaining load and escaped magnetic particles output from the second bed unit. If the active magnetic seed bed adopts a parallel or partial bypass structure, the load calculation unit allocates the incoming load according to the actual flow ratio of each branch. After the incoming load enters the same bed unit, its status is recorded and correlated with the magnetic spectral fingerprint formed by that bed unit during the same sampling period.

[0033] The load accumulation status indicates the degree to which fouling has accumulated within the bed unit but has not yet been released through demagnetization and stripping. An increase in weak magnetic response capture indicates insufficient binding of pollutants to magnetic seeds or a decrease in the capture capacity of active magnetic seeds; an increase in strong magnetic response capture indicates the formation of more stable fouling-laden magnetic seeds within the bed; an increase in magnetic seed leakage indicates that magnetic particles have crossed the bed's retention area; and an increase in differential pressure indicates particle accumulation or hydraulic channel contraction within the bed. The load calculation unit determines the load accumulation status based on these parameters, not relying on a single parameter as the sole criterion. High weak magnetic response capture and magnetic seed leakage tend to reflect insufficient bed retention capacity; high strong magnetic response capture and differential pressure tend to reflect accumulation of fouling-laden magnetic seeds within the bed.

[0034] The cumulative load corresponding to the cumulative load state is calculated based on the magnetic capture parameters within the same statistical period. The weak magnetic response capture amount, strong magnetic response capture amount, and magnetic seed leakage amount are converted into mass load according to the statistical period, and the pressure difference change is calibrated as the equivalent load correction amount based on historical stable operation data; each conversion factor is determined by the clean bed calibration test and stable operation data, and remains unchanged within the same operating period.

[0035] Unstripped pollution load can be determined using the following formula:

[0036] in, For the first The unremoved contamination load of each bed unit; For the first The incoming load of each bed unit; For the first The cumulative load corresponding to the load accumulation state of each bed unit; For the first The expression represents the pollution load released by a bed unit through demagnetization and stripping within the current statistical period. It unifies externally introduced pollutants, internal contamination accumulation, and released loads into the same bed unit state. The calculated unstripped pollution load is stored according to the bed unit number and sampling period and then passed to the stripping condition judgment stage. If the unstripped pollution load of a certain bed unit continues to increase, and the corresponding magnetic fingerprint shows synchronous abnormalities in weak magnetic response capture, magnetic seed leakage, or differential pressure changes, the load calculation unit marks this bed unit as a key judgment target. The subsequent replay verification stage determines whether this change originates from historical pollution load impacts.

[0037] After receiving the unstripped contamination load from each bed unit, the load judgment unit compares it with the stripping conditions. The stripping conditions can be set based on the bed's designed contamination capacity, allowable differential pressure range, magnetic seed leakage control requirements, and historical stable operating data. These conditions determine whether a bed unit needs to enter the demagnetization stripping process. When any bed unit meets the stripping conditions, the load judgment unit does not directly designate that bed unit as a stripping target. Instead, it retrieves historical contamination loads and historical magnetic spectrum fingerprints, replaying them according to the wastewater's residence time in the activated magnetic seed bed. The replay results are used to distinguish between short-term load increases caused by influent shocks and actual stripping needs caused by contamination accumulation within the bed. Bed units that fail the verification are output as bed units to be stripped and transferred to the demagnetization stripping stage.

[0038] In one embodiment, historical pollution loads are stored according to continuous time windows, with each time window corresponding to influent flow rate, turbidity, suspended solids concentration, total phosphorus concentration, and operating time markers. Historical magnetic spectral fingerprints are stored according to bed unit number and sampling period, with each record including strong magnetic response capture amount, medium magnetic response capture amount, weak magnetic response capture amount, residual turbidity, magnetic seed leakage, and differential pressure change. The above historical data needs to be time-aligned before entering the replay process, based on the residence time of wastewater in different bed units. Residence time can be determined based on the effective bed volume, real-time flow rate, local valve opening, and bed operating mode; for series-connected beds, residence time is accumulated according to the order in which water flows through each bed unit, while for parallel beds, residence time is determined separately according to the actual flow rate of each branch. When an abnormal jump occurs in residence time, the control unit can use the residence time of the most recent stable operating period as a temporary value and mark this replay as a verification record requiring review, avoiding misjudgment of the stripping target due to short-term fluctuations in the flow meter.

[0039] After time alignment, the load assessment unit maps historical pollution loads to each bed unit. The mapping process does not change the detection source of the historical pollution load; instead, it allocates the same pollution input to the corresponding playback period of each bed unit based on the time relationship between the pollution load's entry into the bed and its arrival at each bed unit. For the first bed unit, the mapped historical pollution load mainly reflects the influent-side pollutant input; for the second bed unit, the mapped historical pollution load also needs to be considered in conjunction with the interception data from the previous bed unit; for the third bed unit, the mapped historical pollution load is mainly used to determine changes in residual magnetic particles and magnetic seed leakage on the effluent side. The load assessment unit combines the mapped historical pollution load and historical magnetic spectral fingerprints to estimate the load change trend that should occur in each bed unit during the current period. Predicted load changes are used to characterize the pollution load changes that historical pollution inputs may cause to each bed unit under normal transmission conditions.

[0040] Consistency comparison is performed on the same bed unit, comparing the predicted load change with the actual unstripped contaminant load. If the two changes are in the same direction and the deviation is within the allowable range set based on historical stable operating data, it indicates that the increase in unstripped contaminant load mainly comes from explainable influent fluctuations. The load judgment unit temporarily does not list this bed unit as a stripping target and continues to monitor subsequent magnetic spectrum fingerprints. If the predicted load change cannot explain the increase in unstripped contaminant load, or if the historical magnetic spectrum fingerprint shows that the weak magnetic response capture amount, magnetic seed leakage amount, and differential pressure changes all deviate from the stable operating range, it indicates that there is contaminant accumulation, decreased magnetic seed activity, or local hydraulic channel contraction within the bed unit. In this case, the load judgment unit identifies the bed unit that failed the consistency comparison as the bed unit to be stripped and outputs the bed unit number, trigger time period, unstripped contaminant load, and abnormal magnetic spectrum fingerprint. The above output serves as the input for subsequently determining the local demagnetization stripping window, used to limit the location and execution sequence of the bed unit requiring demagnetization stripping.

[0041] The demagnetizing stripping control unit receives the bed unit to be stripped from the playback verification stage and reads the unstripped contaminant load, bed pressure difference, magnetic field constraint status, and load-bearing status of adjacent bed units. The load-bearing status of adjacent bed units indicates the wastewater flow and contaminant load margin that the adjacent area can handle during the period when the bed unit to be stripped is removed from the treatment process. Based on this, the demagnetizing stripping control unit determines the local demagnetizing stripping window, which limits the range of bed units involved in the stripping, the start time, the duration, and the recovery sequence. After entering this window, the control unit reduces the magnetic field constraint of the bed unit to be stripped, loosening the contaminant-laden magnetic seed from the bed structure. It then carries the seed into the bypass collection pipeline through backwashing, forming a contaminant-laden magnetic seed slurry. The contaminant-laden magnetic seed slurry enters the regeneration treatment stage for subsequent magnetic seed level determination and reinjection treatment.

[0042] In one embodiment, the local demagnetization stripping window is jointly determined by the unstripped contaminant load of the bed unit to be stripped and the load-bearing status of adjacent bed units. The unstripped contaminant load reflects the accumulated but not yet released contaminant load within the bed unit to be stripped; when the value reaches the stripping condition, it indicates that the area needs to be temporarily cut off from the main treatment bed. The load-bearing status of adjacent bed units is determined at least in combination with the current unstripped contaminant load, differential pressure change, magnetic seed leakage, and distributable flow rate of the adjacent area, and is used to determine whether the adjacent area can maintain continuous main water flow treatment during stripping. If the load-bearing status of the adjacent bed unit is insufficient, the demagnetization stripping control unit does not immediately execute stripping, but instead reduces the stripping range, decreases the influent flow rate, or waits for the regenerated magnetic seed to be replenished before activating the window. If the adjacent bed unit has a load-bearing margin, the control unit includes the bed unit to be stripped in the local demagnetization stripping window and generates a sequence of valve isolation, magnetic field adjustment, and flushing execution.

[0043] The bed extent of the local demagnetization stripping window typically does not cover the entire active magnetic seed bed, but is limited to the bed unit to be stripped and necessary local boundary areas. The bed extent is determined based on the numbering of the bed unit to be stripped, the contaminant distribution, and the adjacent load capacity, to avoid two adjacent high-load bed units simultaneously leaving the main treatment channel. The execution sequence is determined based on the wastewater residence time in the bed, the sideflow sampling cycle, and the bypass collection capacity. If the bypass collection pipeline is at a high liquid level, the control unit delays the window activation to prevent the contaminant-laden magnetic seed slurry from flowing back into the main water flow channel. If the pressure differential of the bed unit to be stripped continues to rise and approaches the equipment's allowable upper limit, the control unit can shorten the waiting time and reduce hydraulic disturbance during stripping by decreasing the influent distribution rate.

[0044] Upon entering the partial demagnetization and stripping window, the control unit gradually reduces the magnetic field constraint of the bed unit to be stripped. Magnetic field constraint refers to the holding effect of an external magnetic field, magnetic packing, or magnetic trapping structure on the active magnetic seed bed. Reducing the magnetic field constraint can be achieved by decreasing the electromagnetic coil current, moving the permanent magnet assembly, or switching the local magnetic circuit. The extent of the reduction in magnetic field constraint is determined based on the loosening of the contaminated magnetic seeds and the downstream magnetic seed leakage monitoring results. The principle is to allow the contaminated magnetic seeds to detach from their fixed position in the bed while preventing magnetic particles from entering the treated effluent channel. If the magnetic seed leakage on the effluent side increases during demagnetization, the control unit immediately restores part of the magnetic field constraint and diverts the flushing flow to the bypass collection pipeline.

[0045] After the magnetic field constraint adjustment is completed, the backwashing unit introduces flushing water from the downstream side or side flushing port of the bed unit to be stripped, making the water flow direction opposite to or partially reversed from the conventional treatment water flow direction. The backwashing water volume is set according to the bed porosity, the unstripped contaminant load, and the bypass collection capacity. The constraint principle is to carry the loosened contaminant-laden magnetic seeds out of the bed without disrupting the magnetic seed distribution of adjacent bed units. During the flushing process, the bypass collection pipeline continuously receives contaminant-laden magnetic seeds, sludge flocs, and entrained water, forming a contaminant-laden magnetic seed slurry. The concentration of the contaminant-laden magnetic seed slurry can be comprehensively judged by the pipeline turbidity, magnetic particle concentration, and bypass flow rate. If the concentration is lower than the requirements for subsequent regeneration treatment, the control unit can extend the short-term flushing or return the low-concentration slurry to the bypass thickening tank. After flushing is completed, the bed unit to be stripped enters the recovery state, and the control unit gradually restores the magnetic field constraint and waits for the replenishment of regenerated magnetic seeds or spare active magnetic seeds. After the replacement is completed, the bed unit re-participates in the lateral flow magnetic spectrum fingerprinting. The acquisition results are used to confirm whether the bed state has recovered and to proceed to the next round of unstripped pollution load calculation.

[0046] The regeneration control unit receives the contaminated magnetic seed slurry output from the bypass collection pipeline and detects the state of the magnetic seeds. The detection determines whether the contaminated magnetic seeds are suitable for cleaning, deflocculation, enhanced cleaning, or replacement. Based on the detection results, the regeneration control unit determines the regeneration level and processes the contaminated magnetic seed slurry according to the regeneration level, forming regenerated magnetic seeds that can re-participate in bed capture. After the regenerated magnetic seeds undergo quality verification, they enter the refilling and distribution stage. This stage, considering the post-regeneration quality state and the unstripped contaminant load of each bed unit, determines the bed location where the regenerated magnetic seeds should be added. After refilling, the main treated water continues to flow through the activated magnetic seed bed, and the treated effluent is discharged through the effluent pipeline. The effluent detection unit records turbidity, magnetic seed leakage, and contaminant indicators.

[0047] In one embodiment, after the contaminated magnetic seed slurry enters the regeneration level determination station, the regeneration control unit acquires the magnetic seed response retention status, magnetic seed particle size retention status, and magnetic seed surface contamination status. The magnetic seed response retention status indicates the ability of magnetic seeds to be captured and retained under fixed magnetic field conditions, and can be determined by the standard magnetic capture time, the amount of magnetic particles remaining after magnetic capture, or the proportion of magnetic particles retained per unit time. During testing, a certain volume of contaminated magnetic seed slurry is introduced into a standard magnetic trap, and the magnetic field conditions, flow rate conditions, and test time are kept stable. The test results are compared with a clean magnetic seed baseline record. If the magnetic capture time is significantly prolonged or the amount of remaining magnetic particles increases, it indicates a decrease in the magnetic seed response retention status.

[0048] The magnetic seed particle size retention status indicates the wear, agglomeration, or breakage of the magnetic seeds during circulation, rinsing, and deflocculation processes. This can be obtained through sieving, particle size analysis, or sedimentation distribution testing. The determination of particle size retention status is based on the allowable particle size range of the magnetic seeds in the equipment design, the bypass pumping capacity, and the bed retention capacity. Magnetic seeds with excessively small particle sizes are easily lost with the effluent, while agglomerated magnetic seeds with excessively large particle sizes can easily cause localized blockage in the bed. Therefore, particle size retention status is used not only to determine whether to continue refeeding but also to determine which type of bed unit to enter. The magnetic seed surface contamination status indicates whether there is sludge residue, flocculant coating, organic matter adhesion, or grease contamination on the magnetic seed surface. Surface contamination status can be determined by the amount of suspended solids released before and after cleaning, changes in surface color, grease detection results, and changes in residual turbidity.

[0049] The regeneration control unit classifies the magnetic seeds in the contaminated magnetic seed slurry into four categories: lightly contaminated, moderately contaminated, surface-coated, and degraded. Lightly contaminated magnetic seeds indicate good magnetic response, stable particle size, and low surface contamination, suitable for recovery through hydraulic cleaning. Moderately contaminated magnetic seeds still have usable magnetic response, but their surfaces are covered with numerous flocs or sludge, requiring deflocculation to release non-magnetic sludge. Surface-coated magnetic seeds have grease, organic matter, or flocculant coatings on their surface, making surface activity difficult to restore with conventional hydraulic cleaning; they require enhanced cleaning. Degraded magnetic seeds do not meet reuse conditions in terms of magnetic response or particle size retention; continued reintroduction will increase seed leakage or reduce bed capture capacity. The regeneration level is determined based on the above seed types and serves as the basis for selecting cleaning intensity, deflocculation intensity, and the proportion of supplementary magnetic seeds at the bypass regeneration station. If there are multiple types of magnetic seeds in the same batch of contaminated magnetic seed slurry, the regeneration control unit will process them separately according to type to avoid excessive shearing of lightly contaminated magnetic seeds and to prevent surface-coated magnetic seeds from being directly reintroduced without sufficient treatment.

[0050] In one embodiment, lightly loaded magnetic seeds enter a cleaning branch, where loose surface sludge is removed by rinsing with clean water and low-intensity agitation. The cleaning water then enters a bypass sludge treatment section and does not enter the treated effluent channel. Medium-loaded magnetic seeds enter a deflocculation branch, where controlled shearing disrupts the bridging structure between the sludge flocs and the magnetic seeds, causing non-magnetic sludge to desorb from the seed surface. The deflocculation intensity is determined based on the maintained particle size of the magnetic seeds and the residual turbidity after desorption, avoiding excessive shearing that could cause seed wear. Surface-coated magnetic seeds enter an enhanced cleaning branch, which can remove surface coatings by extending the cleaning time, increasing surface rinsing, or setting up independent cleaning fluid circulation. The cleaning fluid is returned to the sludge treatment section or the front-end conditioning section. Defective magnetic seeds enter a replacement branch, where they are discharged from the circulation system and replaced by replacement magnetic seeds. Replacement magnetic seeds undergo quality testing and surface activation before entering the bed.

[0051] The cleaned magnetic seeds, the deflocculated magnetic seeds, the enhanced cleaned magnetic seeds, and the supplementary magnetic seeds added after the elimination and replenishment process all enter the regeneration magnetic seed temporary storage tank. The regeneration control unit detects the quality status of the regenerated magnetic seeds after regeneration. The quality status after regeneration indicates the suitable location for the regenerated magnetic seeds to re-participate in bed capture. The detection content includes the magnetic seed response retention status, particle size retention status, surface contamination status, and the quantity that can be recycled. The regenerated magnetic seeds that pass the test enter the recycling and distribution stage; the regenerated magnetic seeds that fail the test are returned to the corresponding regeneration branch or enter the elimination and replenishment branch. In the recycling and distribution stage, the unstripped contamination load of each bed unit is read, and the bed unit to be recycled is determined in combination with the bed function. Bed units with high unstripped contamination load and located on the influent side will preferentially receive regenerated magnetic seeds with high surface activity; bed units in the contaminated magnetic seed formation area will preferentially receive regenerated magnetic seeds with a more balanced magnetic response and surface activity; and the interception area on the effluent side will preferentially receive regenerated magnetic seeds with stable magnetic response and good particle size retention.

[0052] When the regenerated magnetic seeds are reintroduced into the reintroduction bed unit, the control unit regulates the reintroduction speed based on the bed pressure difference, local flow rate, and the accommodative bed volume to avoid excessive instantaneous addition that could increase hydraulic resistance. After reintroduction is complete, the reintroduction bed unit re-enters the sideflow monitoring cycle. The sideflow monitoring results are used to confirm whether the magnetic spectral fingerprint has recovered to an operational state. The treated effluent is discharged from the end of the active magnetic seed bed, and the effluent monitoring unit continuously records turbidity, magnetic seed leakage, and target pollutant concentration. If the magnetic seed leakage on the effluent side increases, the regeneration control unit prioritizes checking the reintroduction status of the third bed unit and the magnetic response maintenance status of the regenerated magnetic seeds; if the effluent turbidity increases but the magnetic seed leakage does not increase, the control unit prioritizes checking the unstripped pollutant load and the surface activity of the regenerated magnetic seeds in the influent-side bed unit. Thus, regeneration level determination, regenerated magnetic seed reintroduction, and treated effluent monitoring form a continuous closed loop.

[0053] In one specific embodiment, the treated wastewater is the secondary effluent from a municipal wastewater treatment plant entering the advanced treatment stage. The influent batch number is B-2026-0512-03, and the sampling window is from 10:00 to 10:10. The influent flow rate is 120 m³ / h, the turbidity is 68 NTU, the suspended solids concentration is 42 mg / L, and the total phosphorus concentration is 1.82 mg / L. The operation control unit uses the above data as the basic input for the pollution load and simultaneously reads the detection record of the recovered magnetic seed batch MR-0512-A. The magnetic response retention rate of this batch of recovered magnetic seeds is 0.91, the particle size retention rate is 0.88, the surface contamination index is 0.22, and the refillable amount is 34 kg. The magnetic response retention rate is determined by the capture state under standard magnetic field conditions, the particle size retention rate is determined by comparing the particle size distribution of the recovered magnetic seeds with the reference particle size distribution, and the surface contamination index is determined by the release of suspended solids before and after cleaning and the surface adhesion.

[0054] The values ​​of magnetic response retention rate and particle size retention rate range from 0 to 1, with the closer the value is to 1, the better the retention. The value of surface contamination index ranges from 0 to 1, with the larger the value, the heavier the surface contamination of the magnetic seed.

[0055] like Figure 2 As shown, the influent load and magnetic seed quality field structure is formed by online monitoring records, magnetic seed regeneration records, and bed status records. Figure 2 The left side represents the data of the influent batch, the data of the recovered magnetic seed batch, and the status input of the bed unit, respectively. The right side represents the processing relationship of magnetic seed quality judgment, surface activation, and bed configuration. Figure 2 The table below records the amount of magnetic seed returned, functional markings, and initial loads for the three bed units. Bed unit B1 was configured with 16 kg of magnetic seed returned, functionally marked as pollutant interception, with an initial load of 72.0 kg / d; bed unit B2 was configured with 8 kg of magnetic seed returned, functionally marked as pollutant formation, with an initial load of 18.4 kg / d; and bed unit B3 was configured with 4 kg of magnetic seed returned, functionally marked as end-of-pipe interception, with an initial load of 2.8 kg / d. These data were used to determine the initial configuration of the active magnetic seed bed and served as the basis for subsequent side-flow monitoring of the bed units and calculation of the unstripped pollutant load.

[0056] The magnetic seed activation control unit determines 28 kg of reusable magnetic seeds from the 34 kg of recovered magnetic seeds based on their quality status, with the remainder going to the secondary cleaning or verification branch. After rinsing with clean water and undergoing low-shear dispersion, a low dose of iron salt is added to the magnetic seed slurry to form an active layer on the seed surface capable of adsorbing colloidal particles, phosphates, and fine suspended solids. After surface activation, the control unit allocates 16 kg of highly active magnetic seeds to bed unit B1, 8 kg of relatively balanced magnetic response and surface activity to bed unit B2, and 4 kg of relatively stable magnetic response and concentrated particle size distribution to bed unit B3. When wastewater enters the active magnetic seed bed, bed unit B1 primarily traps suspended solids and colloidal particles, bed unit B2 allows pollutants to form a pollutant-carrying magnetic seed, and bed unit B3 traps fine magnetic particles exiting from bed unit B2.

[0057] After the bed has been running stably for one sampling cycle, the detection and control unit draws side streams from bed units B1, B2, and B3, respectively, with a side stream sampling interval of 5 minutes. The side streams sequentially pass through the low magnetic field gradient capture zone, the medium magnetic field gradient capture zone, and the high magnetic field gradient capture zone, respectively. The strong magnetic response capture amount, the medium magnetic response capture amount, and the weak magnetic response capture amount are recorded, and the residual turbidity, magnetic seed leakage, and pressure difference changes after the high magnetic field gradient capture are recorded simultaneously.

[0058] like Figure 3As shown, the magnetic spectral fingerprint matrix of the bed unit is generated from the lateral flow detection record at time 10:10. Figure 3 The longitudinal axis represents the first bed layer (B1), the second bed layer (B2), and the third bed layer (B3). The transverse axis represents the strong magnetic response, moderate magnetic response, weak magnetic response, residual turbidity, magnetic seed leakage, and pressure difference. The color band on the right indicates the normalized intensity. The B1 bed unit has a strong magnetic response capture rate of 28.6 kg / h, a moderate magnetic response capture rate of 8.4 kg / h, a weak magnetic response capture rate of 1.9 kg / h, a residual turbidity of 12.0 NTU, a magnetic seed leakage rate of 0.4 g / h, and a pressure difference of 7.4 kPa. The B2 bed unit has a strong magnetic response capture rate of 14.2 kg / h, a moderate magnetic response capture rate of 16.5 kg / h, a weak magnetic response capture rate of 6.8 kg / h, a residual turbidity of 18.0 NTU, a magnetic seed leakage rate of 1.1 g / h, and a pressure difference of 5.1 kPa. The B3 bed unit has a strong magnetic response capture capacity of 4.5 kg / h, a medium magnetic response capture capacity of 7.2 kg / h, a weak magnetic response capture capacity of 3.6 kg / h, a residual turbidity of 9.0 NTU, a magnetic seed leakage of 2.4 g / h, and a pressure difference of 3.2 kPa. Figure 3 The relatively high weak magnetic response capture and residual turbidity of the B2 bed unit indicate the presence of poorly bound magnetic composite particles in this region. This magnetic spectral fingerprint is then incorporated into the calculation of the unstripped pollution load.

[0059] The load calculation unit calculates the unstripped contaminant load of each bed unit based on the contamination load, magnetic spectral fingerprint, and demagnetization stripping release records. The calculation uses a relational formula. ,in, For the first Unremoved contamination load of each bed unit For the first The incoming load of each bed unit For the first The cumulative load of each bed unit is calculated from the magnetic spectral fingerprint. For the first The contamination load that a bed unit has released through demagnetization and stripping within the current statistical period. This relationship is used to unify the contamination input entering the bed, the accumulated contamination within the bed, and the released load into the same bed unit state.

[0060] In this embodiment, the influent load of bed unit B1 is 72.0 kg / d, the cumulative load is 18.4 kg / d, the released load is 5.2 kg / d, and the unstripped contaminant load is 85.2 kg / d; the influent load of bed unit B2 is 18.4 kg / d, the cumulative load is 24.6 kg / d, the released load is 0 kg / d, and the unstripped contaminant load is 43.0 kg / d; the influent load of bed unit B3 is 2.8 kg / d, the cumulative load is 9.7 kg / d, the released load is 0 kg / d, and the unstripped contaminant load is 12.5 kg / d. The stripping conditions are set according to the bed design contaminant carrying capacity, the upper limit of stable operating differential pressure, and magnetic seed leakage control requirements. Specifically, the stripping condition for bed unit B1 is an unstripped contaminant load of not less than 80 kg / d, for bed unit B2 it is not less than 40 kg / d, and for bed unit B3 it is not less than 25 kg / d. Therefore, bed units B1 and B2 are put into historical pollution load replay mode, while bed unit B3 continues to be monitored.

[0061] The replay verification unit reads the historical pollution load and historical magnetic spectrum fingerprint from 9:40 to 10:10. The residence times of wastewater in bed units B1, B2, and B3 are 4 min, 6 min, and 5 min, respectively. The control unit maps the historical pollution load to the corresponding bed unit according to these residence times. After mapping, the replay predicted load change for bed unit B1 is 82.1 kg / d, for bed unit B2 it is 29.5 kg / d, and for bed unit B3 it is 11.2 kg / d. The consistency allowable deviation is set at 10 kg / d based on the stable operation records of the past 30 days. After comparing the replay-predicted load changes with the unstripped contaminant loads of the same bed unit, the deviation of bed unit B1 was 3.1 kg / d, which is within the explainable range of influent shock; the deviation of bed unit B2 was 13.5 kg / d, which exceeded the allowable deviation and was identified as a bed unit to be stripped; the deviation of bed unit B3 was 1.3 kg / d and was not included in the stripping.

[0062] like Figure 4 As shown, the historical pollution load replay and pending stripping judgment diagram is generated from the above replay verification data. Figure 4 The horizontal axis represents the first bed layer (B1), the second bed layer (B2), and the third bed layer (B3), while the vertical axis represents the load. Blue bars represent the replay-predicted load changes, and orange bars represent the unstripped pollution load. The text above each bed layer unit indicates the deviation between the replay-predicted load changes and the unstripped pollution load, with a deviation threshold of 10 kg / d. Figure 4 The difference between the two sets of columns corresponding to the second bed layer of B2 is 13.5 kg / d, and it is marked as to be stripped, which is used to illustrate that the load change of this bed layer unit cannot be explained by historical water inrush.

[0063] The demagnetizing stripping control unit reads the unstripped contamination load of 43.0 kg / d for bed unit B2 and the load status of adjacent bed units. Although bed unit B1 has a high unstripped contamination load, it passed replay verification and can still undertake part of the front-end interception task; bed unit B3 has a high magnetic seed leakage and is not used as the main load unit, only retaining the end interception function. Based on this, the control unit determines the local demagnetizing stripping window to be from 10:18 to 10:22, and the stripping target is limited to bed unit B2. After the window is opened, the control unit reduces the local magnetic field constraint of bed unit B2 and introduces backwash water from the downstream side of bed unit, with the backwash flow rate controlled at 8% of the main flow rate. The flushing yields contaminant-loaded magnetic seed slurry S-0512-B2, with a slurry concentration of 3.8%, a magnetic response retention rate of 0.74, a particle size retention rate of 0.82, and a surface contamination index of 0.48, which enters the bypass regeneration unit.

[0064] The regeneration control unit determines the regeneration level based on the seed response maintenance state, seed particle size maintenance state, and seed surface contamination state in the contaminated magnetic seed slurry. Test results show that 12 kg of seed in the slurry is lightly contaminated and is cleaned using hydraulic washing; 9 kg of seed is moderately contaminated and is deflocculated using controlled deflocculation; and 3 kg of seed is considered ineffective and is replaced by supplementary seed. The cleaned seed, the deflocculated seed, and the supplementary seed are combined to form 24 kg of regenerated seed R-0512-B. Post-regeneration quality status testing showed that the overall magnetic response retention rate of the regenerated magnetic seeds was 0.86, the particle size retention rate was 0.87, and the surface contamination index decreased to 0.18. The post-regeneration quality used in the refeeding distribution was the bed matching evaluation value, which was determined by the magnetic response retention rate, particle size retention rate, surface contamination index, and functional weight of the target bed unit. The bed matching evaluation value was determined by weighting the magnetic response retention rate, particle size retention rate, and surface contamination index after homogenization processing. The surface contamination index was calculated using an inverse index. The functional weight of the target bed unit was preset according to three types of bed functions: pollutant interception, contaminated magnetic seed formation, and end-of-pipe interception, and remained unchanged within the same operating cycle.

[0065] The first bed unit increases the weight of the inverse indicator of surface contamination index; the second bed unit evenly sets the weights of magnetic response retention rate and the inverse indicator of surface contamination index; and the third bed unit increases the weights of magnetic response retention rate and particle size retention rate. During the regeneration and distribution phase, based on the post-regeneration quality status and the unremoved contamination load of each bed unit, 14 kg of regenerated magnetic seeds are regenerated and distributed to bed unit B1, 7 kg to bed unit B2, and 3 kg to bed unit B3.

[0066] like Figure 5 As shown, the relationship between the regeneration level of the contaminated magnetic seed and the refeeding is generated from the bypass regeneration record and the refeeding allocation record. Figure 5The left side shows the source and status fields of the contaminated magnetic seed slurry S-0512-B2. The middle section shows the diversion relationship between status detection, lightly contaminated magnetic seed hydraulic cleaning, medium-contaminated magnetic seed controlled deflocculation, surface-coated magnetic seed enhanced cleaning, and failed magnetic seed replacement. The central area shows the composition of the regenerated magnetic seed R-0512-B. The bottom section shows the distribution results of the re-feedback to B1, B2, and B3. Figure 5 The regenerated quality of bed unit B1 is 0.88, with an unstripped load of 85.2 kg / d and a distribution of 14 kg; the regenerated quality of bed unit B2 is 0.81, with an unstripped load of 43.0 kg / d and a distribution of 7 kg; and the regenerated quality of bed unit B3 is 0.90, with an unstripped load of 12.5 kg / d and a distribution of 3 kg. This figure is consistent with the regeneration control unit's refill strategy, illustrating that the regenerated magnetic seed is not refilled evenly, but rather the refill location is determined based on the regenerated quality status and the unstripped contamination load of the bed unit.

[0067] After the reintroduction was completed, the effluent monitoring unit recorded the treated effluent data from 10:35 to 10:45. The effluent turbidity decreased from 9.6 NTU before reintroduction to 5.8 NTU, the magnetic seed leakage decreased from 2.4 g / h to 0.8 g / h, and the total phosphorus concentration decreased from 0.42 mg / L to 0.21 mg / L. After demagnetization and stripping, the second bed unit re-entered the side-flow monitoring cycle. At 10:45, the weak magnetic response capture rate decreased to 2.9 kg / h, and the pressure difference decreased from 5.1 kPa to 3.6 kPa, indicating that the pollutant-laden magnetic seed slurry had been released from this bed unit and entered the regeneration cycle. Thus, the treatment system completed the entire execution chain from influent load identification, magnetic spectrum fingerprint generation, unstripped pollutant load judgment, determination of the bed unit to be stripped, pollutant-laden magnetic seed regeneration, to treated effluent output.

[0068] like Figure 6 As shown, a wastewater treatment system based on magnetic coagulation separation and magnetic seed recovery includes the following modules.

[0069] The acquisition module consists of an inlet sampling pipeline, a flow meter, a turbidity detector, a suspended solids detector, a total phosphorus detector, a pH detector, a temperature detector, a magnetic seed recovery sampling port, a magnetic particle detector, a particle size detection unit, and a data acquisition controller. It is used to simultaneously acquire wastewater operation data, pollution load data, recovered magnetic seed samples, and magnetic seed quality status data.

[0070] The activation module consists of a magnetic seed storage tank, a magnetic seed metering pump, a cleaning tank, a low-shear disperser, a reagent dosing pump, a surface activation reaction tank, a stirring mechanism, and a bed distributor. It is used to clean, disperse, construct and distribute the recovered magnetic seeds in different zones, and form an active magnetic seed bed containing multiple bed units in the reactor.

[0071] The capture module consists of a sideflow sampling pipeline, a sideflow metering pump, a low magnetic field gradient capture device, a medium magnetic field gradient capture device, a high magnetic field gradient capture device, a turbidity detector, a magnetic seed leakage detector, a differential pressure sensor, and a capture data acquisition unit. It is used to perform graded magnetic capture of the sideflow drawn from each bed unit and to form a magnetic spectral fingerprint for characterizing the magnetic response state of the bed.

[0072] The load module consists of an industrial controller, an operating data storage unit, a bed unit status register unit, and a load calculation processor. It is used to receive pollution load and magnetic spectrum fingerprint, and determine the unstripped pollution load of each bed unit by combining the bed unit number, sampling period, incoming load, magnetic response change and pressure difference change.

[0073] The replay module consists of a historical data storage unit, a time synchronization unit, a residence time configuration unit, and a replay verification processor. It is used to call up historical pollution loads and historical magnetic spectrum fingerprints, and map the historical pollution loads to each bed unit according to the residence time of wastewater in the active magnetic seed bed, thereby determining the bed unit to be stripped.

[0074] The stripping module consists of a bed isolation valve group, a local magnetic field adjustment unit, a backwash pump, a flushing water pipeline, a bypass collection pipeline, a slurry concentration detector, and a stripping controller. It is used to reduce the magnetic field constraint of the bed unit to be stripped within the local demagnetization stripping window, and to introduce the contaminated magnetic seed into the bypass pipeline through backwashing to obtain the contaminated magnetic seed slurry.

[0075] The regeneration module consists of a temporary storage tank for the polluted magnetic seed slurry, a magnetic seed grading and detection unit, a cleaning tank, a deflocculation device, an enhanced cleaning branch, a failed magnetic seed discharge mechanism, a replenishment magnetic seed addition mechanism, a regenerated magnetic seed storage tank, a return pump, and a return pipeline. It is used to clean, deflocculate, enhance cleaning, or replace and replenish the magnetic seeds in the polluted magnetic seed slurry according to the regeneration level, and return the formed regenerated magnetic seeds to the corresponding bed unit, while outputting the treated effluent.

[0076] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A wastewater treatment method based on magnetic coagulation separation and magnetic seed recovery, characterized in that, The method includes: Receive wastewater to be treated, and obtain the pollution load, recovered magnetic seeds, and magnetic seed quality status of the wastewater to be treated; The recovered magnetic seeds are activated according to the quality status of the magnetic seeds to form an active magnetic seed bed containing multiple bed units through which the wastewater to be treated flows. The active magnetic seed bed includes a first bed unit, a second bed unit, and a third bed unit arranged along the sewage flow direction. The first bed unit is used to intercept pollutants in the sewage to be treated, the second bed unit is used to form pollutant-carrying magnetic seeds, and the third bed unit is used to intercept magnetic particles output from the second bed unit. The sideflow of each bed unit is subjected to graded magnetic capture, including: drawing sideflow from the first bed unit, the second bed unit, and the third bed unit respectively; performing graded magnetic capture on the sideflow according to different magnetic field gradients to obtain magnetic capture parameters including strong magnetic response capture amount, medium magnetic response capture amount, weak magnetic response capture amount, residual turbidity, magnetic seed leakage amount, and pressure difference change; and generating a magnetic spectral fingerprint characterizing the magnetic response distribution and contamination state of each bed unit based on the magnetic capture parameters. The unstripped contamination load of each bed unit is determined based on the contamination load and the magnetic spectral fingerprint. The unstripped contamination load is used to characterize the contamination load that has accumulated in each bed unit and has not yet been released through demagnetization stripping. When any of the unstripped contamination loads meets the stripping conditions, the historical contamination loads and historical magnetic spectrum fingerprints are replayed and verified to determine the bed unit to be stripped. The bed unit to be stripped is demagnetized and stripped to obtain a contaminant-loaded magnetic seed slurry; The regeneration level is determined based on the pollutant-carrying magnetic seed slurry, and the pollutant-carrying magnetic seed slurry is treated according to the regeneration level to obtain regenerated magnetic seeds. The regenerated magnetic seeds are then fed back into the active magnetic seed bed and the treated effluent is output. The regeneration level is determined based on the following steps: The magnetic seed response retention state, magnetic seed particle size retention state, and magnetic seed surface contamination state in the contaminated magnetic seed slurry are obtained. The magnetic seed response retention state is used to characterize the capture and retention ability of magnetic seeds under fixed magnetic field conditions. The magnetic seed particle size retention state is used to characterize the deviation of magnetic seed particle size from the reference particle size distribution. The magnetic seed surface contamination state is used to characterize the adhesion of contaminants on the magnetic seed surface. Based on the magnetic seed response retention state, the magnetic seed particle size retention state, and the magnetic seed surface contamination state, the magnetic seeds in the contaminated magnetic seed slurry are identified as lightly contaminated magnetic seeds, moderately contaminated magnetic seeds, surface-coated magnetic seeds, or failed magnetic seeds. The regeneration level is determined based on the identified magnetic seed type.

2. The method according to claim 1, characterized in that, The step of activating the recovered magnetic seeds according to their quality status to form an activated magnetic seed bed containing multiple bed units through which the wastewater to be treated flows includes: The reusable magnetic seeds among the recovered magnetic seeds are determined based on the quality status of the magnetic seeds. The refillable magnetic seeds are surface activated to obtain active magnetic seeds; The active magnetic seeds are configured into the first bed unit, the second bed unit, and the third bed unit according to their respective bed functions.

3. The method according to claim 1, characterized in that, The determination of the unstripped contamination load for each bed unit based on the contamination load and the magnetic spectral fingerprint, wherein the unstripped contamination load characterizes the contamination load that has accumulated within each bed unit and has not yet been released through demagnetization and stripping, includes: The entry load of each bed unit is determined based on the pollution load. The load accumulation state of each bed unit is determined based on the weak magnetic response capture amount, the strong magnetic response capture amount, the magnetic seed leakage amount, and the pressure difference change; The unstripped contamination load of each bed unit is determined based on the incoming load and the accumulated load status.

4. The method according to claim 1, characterized in that, The process of replaying and verifying historical pollution loads and historical magnetic spectral fingerprints to determine the bed units to be stripped includes: Based on the residence time of the wastewater to be treated in the activated magnetic seed bed, the historical pollution load is mapped to each bed unit; Based on the mapped historical pollution load and the historical magnetic spectrum fingerprint, the predicted load change of each bed unit is determined; The predicted load change is compared with the unstripped contamination load of the same bed unit, and the bed unit that fails the consistency comparison is identified as the bed unit to be stripped.

5. The method according to claim 1, characterized in that, The process of demagnetizing and stripping the bed unit to be stripped to obtain a contaminant-laden magnetic seed slurry includes: Based on the unstripped pollution load of the bed unit to be stripped, and the carrying capacity of adjacent bed units to characterize the sewage flow and pollution load margin that can be received during demagnetization stripping, the bed units to limit demagnetization stripping and the local demagnetization stripping window for execution timing are determined. Within the local demagnetization stripping window, the magnetic field constraint of the bed unit to be stripped is reduced, and the bed unit to be stripped is reverse-washed to obtain the contaminated magnetic seed slurry.

6. The method according to claim 1, characterized in that, The step of determining the regeneration level based on the polluted magnetic seed slurry, treating the polluted magnetic seed slurry according to the regeneration level to obtain regenerated magnetic seeds, and then feeding the regenerated magnetic seeds back into the activated magnetic seed bed and outputting treated effluent includes: Based on the regeneration level, the magnetic seeds in the polluted magnetic seed slurry are cleaned, deflocculated, intensified cleaned, or eliminated and supplemented, and at least one of the cleaned magnetic seeds, deflocculated magnetic seeds, intensified cleaned magnetic seeds, and supplemented magnetic seeds added after elimination and supplementation are determined as the regenerated magnetic seeds. Obtain the quality status of the regenerated magnetic seeds after regeneration; Based on the post-regeneration quality status and the unstripped contamination load of each bed unit, the bed unit for re-injecting the regenerated magnetic seeds is determined. The regenerated magnetic seeds are reintroduced into the reintroduction bed unit.

7. A wastewater treatment system based on magnetic coagulation separation and magnetic seed recovery, used to implement the wastewater treatment method based on magnetic coagulation separation and magnetic seed recovery as described in any one of claims 1 to 6, characterized in that, The system includes: The acquisition module is used to receive the wastewater to be treated and acquire the pollution load, recovered magnetic seeds, and magnetic seed quality status of the wastewater to be treated. An activation module is used to activate the recovered magnetic seeds according to the quality status of the magnetic seeds, forming an active magnetic seed bed containing multiple bed units through which the wastewater to be treated flows. The capture module is used to perform graded magnetic capture of the sideflow of each bed unit to obtain magnetic spectral fingerprints that characterize the magnetic response distribution and fouling state of each bed unit. The load module is used to determine the unstripped contamination load of each bed unit based on the contamination load and the magnetic spectrum fingerprint. The unstripped contamination load is used to characterize the contamination load that has accumulated in each bed unit and has not yet been released by demagnetization stripping. The replay module is used to replay and verify the historical pollution load and historical magnetic spectrum fingerprint when any of the unstripped pollution loads meets the stripping conditions, and to determine the bed unit to be stripped. The stripping module is used to demagnetize and strip the bed unit to be stripped to obtain a contaminant-loaded magnetic seed slurry. The regeneration module is used to determine the regeneration level based on the polluted magnetic seed slurry, process the polluted magnetic seed slurry according to the regeneration level to obtain regenerated magnetic seeds, and then feed the regenerated magnetic seeds back into the active magnetic seed bed and output the treated effluent.

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