A magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent

Abstract

This invention discloses a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent, belonging to the field of deep wastewater treatment technology. It includes treating secondary effluent; an equalization tank designed for a 2-hour hydraulic retention time to control the influent flow rate; the use of nano-magnetic seeds, dispersed at a concentration of 50-100 g / L, added at 3-8 times the effluent TP concentration; containing a nitrogen-removing oxidant, phosphorus-removing PAC, and NaOH, with the reaction pH controlled at 6.5-7.5; separate fast and slow zones to control retention time and stirring intensity; a circular tank equipped with inclined tubes and permanent magnets to separate and intercept unseparated magnetic seeds; a high-gradient magnetic separator to recover the magnetic seeds; online water quality monitoring, alarming and adjusting reagents when standards are exceeded; and effluent sent for further treatment or discharge. This invention improves the efficiency and stability of nitrogen and phosphorus removal in effluent, reduces waste of reagents and magnetic seeds to lower costs, achieves automatic parameter control and fault early warning, responds to emergencies, ensures stable effluent compliance, and is suitable for the needs of wastewater treatment plants.

Description

Technical Field

[0001] This invention relates to the field of advanced treatment technology for wastewater effluent from wastewater treatment plants, and in particular to a magnetic loading clarification system for advanced nitrogen and phosphorus removal from wastewater effluent from wastewater treatment plants. Background Technology

[0002] With increasingly stringent environmental protection requirements, my country has set higher standards for TN and TP indicators in wastewater treatment plant effluent. Most secondary treatment effluent (TN 15-25 mg / L, TP 0.5-1.5 mg / L) requires advanced treatment to meet the Class A or higher requirements of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002). In traditional advanced nitrogen and phosphorus removal processes for effluent, biological nitrogen removal relies on microbial activity and is significantly affected by water temperature and carbon-to-nitrogen ratio. At low temperatures (<15℃), nitrogen removal efficiency drops sharply, and additional carbon sources are required, increasing operating costs. Chemical phosphorus removal involves adding aluminum salts, iron salts, etc., to form flocs, but the dosage depends on experience, which can easily lead to insufficient dosage resulting in incomplete phosphorus removal, or excessive dosage causing problems such as increased COD in the effluent and a surge in sludge volume. The difficulty and cost of subsequent sludge disposal increase simultaneously. In addition, traditional sedimentation processes (such as inclined tube sedimentation tanks) have long hydraulic retention times (30-60 minutes), require a large area, and have limited removal efficiency for low-concentration pollutants, making them difficult to adapt to the compact land use requirements and high-efficiency treatment demands of wastewater treatment plants.

[0003] Magnetic loading clarification technology is increasingly being applied to advanced effluent treatment due to its short hydraulic retention time, small footprint, and high pollutant removal efficiency. However, existing magnetic loading systems still have several technical shortcomings. One issue is the poor dispersion of magnetic seeds, particularly at the nanoscale. Magnetic seeds are prone to agglomeration due to van der Waals forces, forming large particles that cannot fully bind with pollutants, resulting in insufficient floc density and affecting clarification and separation. Although some systems are equipped with ultrasonic dispersion devices, they lack real-time particle size monitoring and dynamic adjustment mechanisms, making it difficult to maintain a stable dispersion effect. On the other hand, the dosing of chemicals and the recovery of magnetic seeds lack precise control. Phosphorus removal chemicals are mostly added using a fixed flow rate mode, which cannot be dynamically adjusted according to the influent TP concentration, resulting in chemical waste or fluctuations in phosphorus removal effect. Magnetic seed recovery mostly relies on magnetic separators with a fixed magnetic field strength. When the concentration of magnetic sludge changes, the recovery rate can easily drop below 90%. Unrecovered magnetic seeds are lost with the effluent or enter the sludge system, which not only increases the cost of magnetic seed replenishment but may also lead to the risk of heavy metal leaching during subsequent sludge treatment.

[0004] Existing magnetic loading clarification systems suffer from poor overall coordination and insufficient control capabilities. During the mixing reaction, the monitoring and adjustment of key parameters such as pH and ORP are disconnected from reagent dosing. When the pH of the reaction system deviates from the optimal range (6.5-7.5), it cannot be corrected in time, affecting the efficiency of nitrogen and phosphorus removal. Clarification tank sludge discharge often adopts a timed discharge mode without considering the adjustment of sludge interface height and concentration. Excessive sludge discharge leads to magnetic seed loss, while insufficient discharge causes sludge accumulation and reduced tank volume, further reducing clarification efficiency. Furthermore, the system lacks effective fault warning and emergency response mechanisms. When unexpected situations such as equipment overload, reagent supply interruption, or effluent exceeding standards occur, manual intervention is required, and the delayed response can easily lead to pollution accidents. Simultaneously, the maintenance of key equipment (such as magnetic separators and metering pumps) relies on periodic inspections, making it impossible to predict faults based on operating parameters, easily leading to unplanned shutdowns and affecting the continuous and stable operation of the system. These problems prevent existing magnetic loading clarification systems from fully leveraging their technological advantages, hindering their large-scale application in the advanced treatment of wastewater effluent. Summary of the Invention

[0005] The present invention proposes a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent, in order to solve the problems mentioned in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent, comprising:

[0007] Water inlet regulating module: The tank is equipped with a vertical agitator, and a liquid level sensor and a flow sensor are installed on the side wall of the tank. The water inlet flow is controlled by the sensor signal to link the water inlet valve. The regulating tank is made of reinforced concrete and the inner wall is treated with epoxy resin for corrosion protection.

[0008] Magnetic seed dispensing module: using nanoscale... The magnetic seed is equipped with a magnetic seed dissolution and dispersion tank. An ultrasonic disperser is installed inside the tank to ensure uniform dispersion of the magnetic seed. After dispersion, the concentration of the magnetic seed suspension is controlled at 50-100 g / L. The dosing equipment uses a screw metering pump. The dosing amount is dynamically adjusted according to the TP concentration of the tailwater. The dosing ratio is 5 times the TP concentration of the tailwater. The dosing pipeline is made of stainless steel and an electromagnetic flow meter is installed on the pipeline to monitor the dosing flow in real time.

[0009] The reagent dosing module includes a denitrification reagent dosing unit, a phosphorus removal reagent dosing unit, and an alkalinity adjustment unit. The denitrification reagent is a 20-30% concentration hydroxyl radical oxidant, added via a plunger metering pump. The dosage is calculated based on the TN removal requirements of the effluent, with 2-5 mg / L of oxidant added for every 1 mg / L of TN removed. The phosphorus removal reagent is a 10-15% concentration polyaluminum chloride, added via a diaphragm metering pump. The alkalinity adjustment unit uses a 20% concentration NaOH solution, added via a screw metering pump, to control the pH of the reaction system at 6.5-7.5. Each reagent dosing pipeline is equipped with a Y-type filter and a pressure sensor, and the reagent storage tank is equipped with a level gauge.

[0010] The mixing and reaction module is divided into a rapid mixing zone and a slow reaction zone. The rapid mixing zone uses a pipeline mixer with a hydraulic residence time of 10-20 seconds and a stirring intensity of [missing information]. The system utilizes built-in spiral blades to achieve rapid mixing of reagents, magnetic seeds, and effluent; the slow reaction zone is a plug-flow reaction tank with an effective volume of 100-500 m³ per tank and a hydraulic retention time of 15-30 min. A horizontal agitator is installed within the tank, providing high mixing intensity. Five sets of pH and ORP sensors are installed along the reaction tank. The sensor data is transmitted to the central control system in real time to dynamically adjust the dosage of the reagents.

[0011] Magnetic loading clarification module: It adopts a circular clarification tank with central water inlet and peripheral water outlet. The top of the tank is equipped with a water distribution trough, and the water is evenly distributed through perforated pipes. The middle of the tank is equipped with an inclined tube sedimentation zone. The inclined tubes are made of polypropylene, and a supporting grid is installed below the packing. The bottom of the tank is equipped with a permanent magnet separation device using neodymium iron boron permanent magnets. The perimeter of the tank is equipped with an outlet weir, and an outlet channel is connected after the outlet weir. An interception filter screen is installed in the outlet channel to intercept unseparated magnetic seeds.

[0012] Sludge return and magnetic seed recovery module: A conical sludge hopper is installed at the bottom of the clarifier, and a sludge pump is connected to the bottom of the hopper to transport magnetic sludge to the magnetic seed recovery device; the magnetic seed recovery device adopts a high-gradient magnetic separator, and the magnetic separator outlet is divided into magnetic seed concentrate and demagnetized sludge. The magnetic seed concentrate is returned to the magnetic seed dissolution and dispersion tank through a return pump, and the demagnetized sludge is transported to the sludge treatment system of the sewage treatment plant through a sludge pump; the magnetic seed recovery pipeline is equipped with a magnetic seed concentration sensor and a turbidity meter to monitor the magnetic seed recovery effect in real time;

[0013] Effluent monitoring and control module: An effluent buffer tank is installed at the end of the effluent channel. The buffer tank is equipped with an online monitoring instrument group, including an online TN monitor, an online TP monitor, an online COD monitor, and an online pH monitor. The monitoring data is transmitted to the central control system. When the effluent TN ≥ 10 mg / L or TP ≥ 0.3 mg / L, the central control system automatically triggers an alarm and adjusts the dosage of denitrification or phosphorus removal agents accordingly. The effluent from the buffer tank is then pumped to the subsequent advanced treatment unit or discharged.

[0014] Furthermore, it also includes:

[0015] Phosphorus removal agent dosing control module: via formula Q p =k×(C0-C e )×Q w Calculate the real-time dosage of polyaluminum chloride, where Q p The dosage of polyaluminum chloride is given, k is the reagent coefficient, C0 is the influent TP concentration, and C e Q represents the target TP concentration in the effluent. w This refers to the effluent treatment flow rate.

[0016] Magnetic seed dispersion enhancement module: Located inside the magnetic seed dissolution and dispersion tank, in addition to the original ultrasonic disperser, a mechanical stirring device and an online particle size analyzer are added. The mechanical stirring and ultrasonic dispersion work together. The mechanical stirring achieves overall mixing of the magnetic seed suspension, while the ultrasonic dispersion breaks down magnetic seed agglomerates. The online particle size analyzer monitors the magnetic seed particle size distribution in real time. When the proportion of magnetic seeds with a particle size ≥150nm is ≥10%, the central control system automatically increases the power of the ultrasonic disperser and extends the stirring time.

[0017] The adaptive control module for the reaction process dynamically adjusts the dosage of alkalinity regulator and denitrification agent based on pH and ORP sensor data from the mixed reaction module. When the pH sensor reading is <6.5, the central control system controls the NaOH metering pump to increase the dosage until the pH rises back to the 6.5-7.5 range. When the ORP sensor reading is <200mV, indicating insufficient denitrification agent, the central control system controls the hydroxyl radical oxidant metering pump to increase the dosage. When the ORP reading is >400mV, the oxidant dosage is reduced. Simultaneously, the module adjusts the stirrer speed according to the hydraulic residence time in the slow reaction zone.

[0018] Furthermore, it also includes:

[0019] Magnetic seed recovery efficiency dynamic evaluation module: through formula Calculate the magnetic seed recovery rate per unit time, where Q represents the magnetic seed recovery rate, t0 is the evaluation start time, t1 is the evaluation end time, and Q is the magnetic seed recovery rate. r C is the magnetic seed reflux flow rate. r Q represents the concentration of the reflux magnetic seed concentrate. w For the demagnetized sludge flow rate, C w Q represents the concentration of magnetic seeds in the demagnetized sludge. m To increase the flow rate of the magnetic seed, C m This refers to the concentration of the magnetic seed addition solution.

[0020] The intelligent sludge discharge control module for the clarifier adjusts the sludge discharge frequency and duration based on the sludge interface height and sludge concentration in the clarifier hopper. A sludge interface meter and a sludge concentration meter are installed in the hopper. When the sludge interface height is ≥1.0m or the sludge concentration is ≥3000mg / L, the central control system starts the sludge pump to discharge sludge. The discharge duration is calculated according to the formula... Calculation, where T is the sludge discharge time, V is the effective volume of the sludge hopper, C is the current sludge concentration, and C0 is the sludge concentration. s Let Q be the target sludge concentration and C be the sludge pump flow rate. The sludge concentration is monitored in real-time during sludge discharge; when the concentration drops to C... s The sludge discharge will automatically stop when the time comes.

[0021] The reagent stability assurance module equips each reagent storage tank with temperature control and stirring devices. The denitrification reagent storage tank is equipped with a low-temperature heating device to reduce reagent crystallization at low temperatures. The phosphorus removal reagent storage tank is equipped with a vertical stirrer, stirring twice a day for 30 minutes each time to reduce PAC solution stratification. The NaOH storage tank is equipped with a corrosion-resistant stirrer for real-time stirring to ensure uniform concentration. Each reagent storage tank is also equipped with a density meter; when the density deviation exceeds the set value ±0.02 g / cm³, an abnormal reagent concentration alarm is triggered, reminding operators to replenish or adjust the reagent concentration.

[0022] Furthermore, it also includes: a module for predicting and proactively controlling nitrogen removal efficiency: using formulas... Calculate the TN removal rate at different reaction times, where R t denoted as TN removal rate at reaction time t, where t is the reaction time, k is the denitrification reaction rate constant, C is the real-time TN concentration during the reaction, and C0 is the influent TN concentration.

[0023] Equipment maintenance early warning module: Real-time monitoring of the operating parameters of equipment within the system, including operating current, operating temperature, operating time, and fault codes; overload warning triggered when the agitator operating current exceeds 110% of the rated current or the temperature is ≥70℃; maintenance warning triggered when the metering pump flow deviation exceeds the set value ±5% or the operating time is ≥8000h; overhaul warning triggered when the magnetic separator magnetic field strength deviation exceeds the set value ±10% or the operating time is ≥10000h; calibration warning triggered when the online monitoring instrument's data deviation exceeds ±10% for three consecutive tests or the zero drift is ≥0.2mg / L; all warning information is displayed and recorded in the central control system and simultaneously pushed to the administrator's mobile phone to remind them to perform maintenance.

[0024] Emergency Response Module: In the event of a sudden system failure, emergency measures are activated. When the influent flow rate exceeds 120% of the design value, the central control system automatically closes some influent valves to control the flow rate within the design range and opens the emergency overflow pipe of the regulating tank. When the liquid level in any chemical storage tank is below 10% and replenishment is not timely, the emergency chemical dosing tank is activated, and the treatment flow rate is reduced to 50% of the design value. When the magnetic seed recovery device stops, the magnetic seed dosing pump is shut down, magnetic seed dosing is stopped, and the sludge from the clarifier is directly discharged to the sludge treatment system to reduce the accumulation of magnetic seeds in the clarifier. When the online monitoring instrument shows that the water quality indicators exceed the standard, the effluent return valve is opened to return the excess effluent to the influent regulating module for reprocessing. All operations during the emergency response process are recorded in the central control system. After the fault is cleared, the system automatically returns to normal operation mode.

[0025] Compared with existing technologies, the beneficial effects of this invention are:

[0026] The magnetic seed dispersion enhancement module combines mechanical stirring and ultrasonic dispersion with online particle size monitoring and dynamic adjustment to effectively prevent magnetic seed agglomeration, ensure full binding of magnetic seeds and pollutants, and improve floc density and separation efficiency. The denitrification agent uses hydroxyl radical oxidants, which, with adaptive control of the reaction process, can maintain high denitrification activity over a wide water temperature range without the need for additional carbon source addition. The phosphorus removal agent is dynamically adjusted according to the influent TP concentration through a precise dosing control module, which greatly reduces agent waste and sludge volume, ensuring that the effluent TN and TP levels consistently meet standards.

[0027] This invention effectively reduces system operating costs. The magnetic seed recovery efficiency dynamic evaluation module calculates the recovery rate in real time using an integral formula. Combined with automatic adjustments to the magnetic field strength and processing flow rate, it maintains the magnetic seed recovery rate at a stable high level, reducing the amount of magnetic seed replenishment. The reagent stability assurance module avoids problems such as low-temperature crystallization and solution stratification, ensuring the effective concentration of reagents and reducing reagent loss. Simultaneously, the clarifier sludge discharge intelligent control module precisely controls the sludge discharge time based on the sludge interface height and concentration, reducing magnetic seed loss caused by excessive sludge discharge, further controlling consumable costs, and meeting the low-cost operation requirements of wastewater treatment plants.

[0028] This invention improves the reliability and automation level of system operation. The denitrification effect prediction and advance control module can predict the effluent TN concentration and adjust process parameters in advance to avoid exceeding the effluent standards. The equipment maintenance early warning module monitors the operating parameters of key equipment in real time and triggers early warnings for overload, maintenance, and repair in a timely manner, reducing unplanned downtime. The emergency response module can quickly activate response measures in case of sudden increases in influent, interruption of reagent supply, or equipment shutdown, reducing the risk of pollution accidents. The entire system realizes parameter monitoring, module linkage, and automatic control through PLC central control, reducing manual intervention and improving operation convenience. It provides an efficient, stable, and economical technical solution for the deep treatment of effluent from wastewater treatment plants, helping to implement environmental protection standards and improve water environment quality. Attached Figure Description

[0029] Figure 1 This is a schematic block diagram of a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent proposed in this invention.

[0030] Figure 2 This is a schematic diagram showing the relationship between the magnetic seed dosage and TP removal rate in a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater effluent of a wastewater treatment plant, as proposed in this invention.

[0031] Figure 3 This is a schematic diagram showing the TN removal rate at different reaction times in a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater effluent proposed in this invention. Detailed Implementation

[0032] 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.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The invention will now be described in further detail with reference to the accompanying drawings.

[0035] Reference Figures 1 to 3 A magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent, comprising:

[0036] Influent regulating module: The treatment target is secondary treated effluent from wastewater treatment plants. The influent water quality indicators are TN 15-25mg / L, TP 0.5-1.5mg / L, and COD 30-50mg / L. The regulating tank volume is designed for a 2-hour hydraulic retention time, with an effective volume of 500-2500m³ per tank. The tank is equipped with a vertical agitator with a speed of 60-80r / min and a stirring power of 0.5-1.0kW / 100m³. A level sensor (measuring range 0-5m, accuracy ±0.01m) and a flow sensor (measuring range 50-600m³ / h, accuracy ±1%) are installed on the side wall of the tank. The sensor signals are used to link the influent valve (electric butterfly valve, diameter DN200-DN500, opening and closing response time ≤3s) to control the influent flow rate to be stable at 100-500m³ / h. The regulating tank is made of reinforced concrete, and the inner wall is treated with epoxy resin for corrosion protection with a thickness of ≥2mm.

[0037] Magnetic seed dispensing module: using nanoscale... Magnetic seeds, with a particle size of 50-100 nm, saturation magnetization of 80-100 emu / g, and a purity ≥99%, are used. A magnetic seed dissolution and dispersion tank (1-5 m³ volume, with a jacketed heating device, temperature control range 25-30℃, heating power 2-5 kW) is installed inside the tank. An ultrasonic disperser (frequency 20-40 kHz, power 300-500 W) ensures uniform dispersion of the magnetic seeds. The concentration of the dispersed magnetic seed suspension is controlled at 50-100 g / L. The addition equipment uses… Screw metering pump (flow range 0-100L / h, flow accuracy ±2%, head 10-15m), the dosage is dynamically adjusted according to the TP concentration of the tailwater, the dosage ratio is 3-8 times the TP concentration of the tailwater (when the TP of the tailwater is 1mg / L, the magnetic seed dosage is 3-8mg / L), the dosing pipeline is made of 316L stainless steel, the pipe diameter is DN25-DN50, and an electromagnetic flow meter (measurement range 0-150L / h, accuracy ±0.5%) is installed on the pipeline to monitor the dosing flow in real time;

[0038] The reagent dosing module includes a denitrification reagent dosing unit, a phosphorus removal reagent dosing unit, and an alkalinity adjustment unit. The denitrification reagent used is a 20-30% concentration hydroxyl radical oxidant (the active ingredient). and (Composite system), the dosing equipment is a plunger metering pump (flow range 0-50L / h, flow accuracy ±1%, head 20-30m), the dosage is calculated according to the TN removal requirements of the effluent, 2-5mg / L oxidant is added for every 1mg / LTN removed; the phosphorus removal agent is 10-15% concentration polyaluminum chloride (PAC, The reagent content is ≥30%, and the dosing equipment is a diaphragm metering pump (flow range 0-100L / h, flow accuracy ±2%, head 15-20m); the alkalinity adjustment unit uses a 20% concentration NaOH solution, and the dosing equipment is a screw metering pump (flow range 0-30L / h, flow accuracy ±1%, head 15-20m) to control the pH of the reaction system at 6.5-7.5; each reagent dosing pipeline is equipped with a Y-type filter (filtration accuracy 50μm) and a pressure sensor (measuring range 0-1MPa, accuracy ±0.01MPa); the reagent storage tank (volume 5-20m³, material PE) is equipped with a level gauge (measuring range 0-3m, accuracy ±0.02m) to realize low liquid level alarm;

[0039] The mixing reaction module is divided into a rapid mixing zone and a slow reaction zone. The rapid mixing zone uses a pipeline mixer (made of 316L stainless steel, diameter DN150-DN400, length 1-2m), with a hydraulic residence time of 10-20s and a stirring intensity of [missing information]. The system utilizes built-in spiral blades to achieve rapid mixing of reagents, magnetic seeds, and effluent. The slow reaction zone is a plug-flow reaction tank with an effective volume of 100-500 m³ per tank and a hydraulic retention time of 15-30 min. A horizontal agitator (20-40 r / min rotation speed, 1.0-2.0 kW / 100 m³ power) is installed within the tank, with a stirring intensity of [missing information]. Three to five sets of pH sensors (measuring range 6-9, accuracy ±0.1) and ORP sensors (measuring range -200-800mV, accuracy ±5mV) are installed along the reaction tank. The sensor data is transmitted to the central control system in real time to dynamically adjust the dosage of the reagent.

[0040] Magnetic loading clarification module: A circular clarification tank with central inlet and peripheral outlet, 5-10m in diameter, 3-4m effective water depth, and a single tank treatment capacity of 100-500m³ / h. An inlet distribution trough (ring-shaped, 0.2-0.3m wide, 0.3-0.5m deep) is located at the top of the tank. Water is evenly distributed through perforated pipes (10-15mm diameter, 50-100mm spacing). An inclined tube sedimentation zone is located in the middle of the tank. The inclined tubes are made of polypropylene, with a regular hexagonal cross-section, 50mm diameter, 1.2m length, and a 60° inclination angle. The height of the inclined tube packing layer is 1.0-1.2m, and a supporting grid is installed below the packing (material...). The pool is constructed of 316L stainless steel with a mesh size of 50×50mm. A permanent magnet separation device is installed at the bottom of the pool, using neodymium iron boron permanent magnets with a magnetic field strength of 0.3-0.5T, a magnetic field distribution uniformity deviation of ≤5%, a separation zone height of 0.5-0.8m, and a hydraulic retention time of 5-10min. An outlet weir (triangular weir, weir height 0.15m, weir crest horizontal error ≤2mm) is installed around the pool perimeter. An outlet channel (width 1-1.5m, flow velocity 0.5-0.8m / s) is connected after the outlet weir. An intercepting filter screen (50μm pore size, 316L stainless steel, filtration area 1-2m²) is installed inside the outlet channel to intercept unseparated magnetic seeds.

[0041] Sludge return and magnetic seed recovery module: A conical sludge hopper (60° cone angle, 1.0-1.5m height) is installed at the bottom of the clarifier. A sludge pump (centrifugal type, flow rate 50-200m³ / h, head 15-20m, 316L stainless steel) is connected to the bottom of the hopper to transport magnetic sludge (2-3% solids content, 500-1000mg / L magnetic seed concentration) to the magnetic seed recovery device. The magnetic seed recovery device uses a high-gradient magnetic separator with a magnetic field gradient... The magnetic separator has a capacity of 50-200 m³ / h, a separation chamber diameter of 300-600 mm, and a processing capacity of 50-200 m³ / h. The outlet of the magnetic separator is divided into magnetic seed concentrate and demagnetized sludge. The magnetic seed concentrate (magnetic seed concentration 100-200 g / L) is returned to the magnetic seed dissolution and dispersion tank via a reflux pump (screw pump, flow range 0-50 L / h, head 10-15 m). The demagnetized sludge (magnetic seed concentration ≤10 mg / L) is transported to the sludge treatment system of the wastewater treatment plant via a sludge pump. A magnetic seed concentration sensor (measuring range 0-1000 mg / L, accuracy ±1 mg / L) and a turbidity meter (measuring range 0-100 NTU, accuracy ±0.5 NTU) are installed in the magnetic seed recovery pipeline to monitor the magnetic seed recovery effect in real time.

[0042] Effluent monitoring and control module: An effluent buffer tank is installed at the end of the effluent channel (the volume is designed for a 1-hour hydraulic retention time, with an effective volume of 100-500 m³). The buffer tank is equipped with an online monitoring system, including a TN online monitor (measurement range 0-50 mg / L, detection limit 0.1 mg / L, accuracy ±0.5 mg / L), a TP online monitor (measurement range 0-5 mg / L, detection limit 0.01 mg / L, accuracy ±0.01 mg / L), a COD online monitor (measurement range 0-100 mg / L, detection limit 1 mg / L, accuracy ±2 mg / L), and a pH monitor. The monitoring instrument (measuring range 5-9, accuracy ±0.1) transmits monitoring data to the central control system (using PLC control system, touch screen operation, supporting data storage and remote transmission) at a frequency of once every 5 minutes. When the effluent TN≥10mg / L or TP≥0.3mg / L, the central control system automatically triggers an alarm (audible and visual alarm, volume ≥80dB, red flashing light) and adjusts the dosage of denitrification or phosphorus removal agents accordingly. The effluent from the buffer tank is transported to the subsequent deep treatment unit or discharged through a booster pump (flow range 100-500m³ / h, head 10-15m).

[0043] This invention also includes:

[0044] Phosphorus removal agent precise dosing control module: This module uses formula Q p =k×(C0-C e )×Q w Calculate the real-time dosage of polyaluminum chloride, where Q p The dosage of polyaluminum chloride is given in L / h, k is the reagent coefficient (dimensionless, value 1.2-1.5, adjusted according to the turbidity of the effluent; k is 1.5 when the turbidity is ≥20 NTU), C0 is the influent TP concentration (mg / L, obtained in real time by the TP sensor of the influent regulating module), and C e Q represents the target TP concentration in the effluent (unit: mg / L, value: 0.1-0.3 mg / L, set according to discharge standards). w The effluent treatment flow rate (unit: m³ / h, obtained in real time by the flow sensor of the influent regulating module) is given by this formula. The dosage of the chemical can be dynamically adjusted according to the TP concentration of the influent, so that the dosage matches the phosphorus removal requirements, reducing chemical waste and insufficient phosphorus removal effect. The dosage calculation result is transmitted to the metering pump of the phosphorus removal chemical dosing unit in real time, and the flow rate of the metering pump is adjusted according to the calculated value. The adjustment response time is ≤1s.

[0045] Magnetic Seed Dispersion Enhancement Module: This module is installed inside the magnetic seed dissolution and dispersion tank. In addition to the original ultrasonic disperser, a mechanical stirring device (paddle type, blade diameter 0.5-1.0m, rotation speed 80-120r / min, power 1.0-2.0kW) and an online particle size analyzer (measurement range 0-1000nm, accuracy ±2nm, detection frequency 1 time / 10min) are added. The mechanical stirring and ultrasonic dispersion work together. The mechanical stirring achieves overall mixing of the magnetic seed suspension, and the ultrasonic dispersion breaks down magnetic seed agglomerates. The online particle size analyzer monitors the magnetic seed particle size distribution in real time. When the proportion of magnetic seeds with a particle size ≥150nm is ≥10%, the central control system automatically increases the power of the ultrasonic disperser (50W each time, maximum power not exceeding 500W) and extends the stirring time (5min each time, maximum stirring time not exceeding 60min) to improve the uniformity of magnetic seed dispersion and the binding efficiency between magnetic seeds and pollutants.

[0046] This invention also includes:

[0047] The adaptive control module for the reaction process dynamically adjusts the dosage of alkalinity regulator and denitrification agent based on pH and ORP sensor data from the mixed reaction module. When the pH sensor reading is <6.5, the central control system controls the NaOH metering pump to increase the dosage (increasing by 10% of the current flow rate each time, with a maximum dosage not exceeding 30 L / h) until the pH rises back to the 6.5-7.5 range. When the ORP sensor reading is <200 mV, indicating insufficient denitrification agent, the central control system controls the hydroxyl radical oxidant metering pump to increase the dosage. (Increase the current flow rate by 5% each time, with a maximum dosage of no more than 50L / h). When the ORP monitoring value is >400mV, reduce the oxidant dosage (reduce the current flow rate by 5% each time, with a minimum dosage of no less than 5L / h). At the same time, the module adjusts the stirrer speed according to the hydraulic residence time in the slow reaction zone (calculated by the flow rate and the volume of the reaction tank). When the residence time is <15min, increase the speed to 40r / min. When the residence time is >30min, decrease the speed to 20r / min to ensure that the reaction is complete and the energy consumption is within a reasonable range.

[0048] Magnetic seed recovery efficiency dynamic evaluation module: This module uses formulas... Calculate the magnetic seed recovery rate per unit time, where t0 is the magnetic seed recovery rate (dimensionless, ranging from 0 to 1), t1 is the evaluation start time (in minutes), t1 is the evaluation end time (in minutes, usually 60 minutes), and Q is the magnetic seed recovery rate (dimensionless, ranging from 0 to 1). r C represents the magnetic seed reflux flow rate (in L / h, obtained from the flow sensor of the magnetic seed reflux pump). r Q represents the concentration of the reflux magnetic seed concentrate (in mg / L, obtained from a magnetic seed concentration sensor). wC represents the flow rate of the demagnetized sludge (in L / h, obtained from the flow sensor of the demagnetized sludge pump). w Q represents the magnetic seed concentration in the demagnetized sludge (unit: mg / L, obtained from a magnetic seed concentration sensor). m C represents the magnetic seed injection flow rate (in L / h, obtained from the electromagnetic flowmeter of the magnetic seed injection pump). m The concentration of the magnetic seed addition solution (unit: mg / L, set at 50000-100000 mg / L) can be used to calculate the total recovery and total addition of magnetic seeds within one hour using this integral formula, thus obtaining the actual recovery rate; when When the flow rate is less than 90%, the central control system automatically adjusts the magnetic field strength of the high-gradient magnetic separator (increasing by 0.05T each time, with a maximum magnetic field strength not exceeding 0.5T) and the processing flow rate (reducing by 10% of the current flow rate each time, with a minimum flow rate not lower than 50m³ / h), until... The efficiency of magnetic seed recycling has been improved to over 90%.

[0049] This invention also includes:

[0050] Clarifier sludge discharge intelligent control module: This module adjusts the sludge discharge frequency and duration based on the sludge interface height and sludge concentration in the clarifier hopper. A sludge interface meter (measuring range 0-2m, accuracy ±0.05m) and a sludge concentration meter (measuring range 0-10000mg / L, accuracy ±100mg / L) are installed in the hopper. When the sludge interface height is ≥1.0m or the sludge concentration is ≥3000mg / L, the central control system starts the sludge pump to discharge sludge. The discharge duration is calculated according to the formula... The calculation is as follows: T is the sludge discharge time (in minutes), V is the effective volume of the sludge hopper (in m³, calculated based on the hopper dimensions), and C is the current sludge concentration (in mg / L, obtained from a sludge concentration meter). s The target sludge concentration is set at 1500-2000 mg / L, and Q is the sludge pump flow rate (m³ / h). The sludge concentration is monitored in real time during the sludge discharge process. When the concentration drops to Cs, the sludge discharge is automatically stopped to reduce the loss of magnetic seeds caused by excessive sludge discharge and the decline in clarification effect caused by insufficient sludge discharge.

[0051] Reagent Stability Assurance Module: This module equips each reagent storage tank with temperature control and stirring devices. The denitrification reagent storage tank (PE material, volume 10-20m³) is equipped with a low-temperature heating device (heating power 5-10kW, temperature control range 15-25℃) to reduce reagent crystallization at low temperatures. The phosphorus removal reagent storage tank is equipped with a vertical stirrer (speed 30-50r / min, power 0.5-1.0kW), stirred twice daily for 30 minutes each time, to reduce PAC solution stratification. The NaOH storage tank is equipped with a corrosion-resistant stirrer (316L stainless steel material, speed 40-60r / min, power 0.5-1.0kW) for real-time stirring to ensure uniform concentration. Each reagent storage tank is also equipped with a density meter (measuring range 1.0-1.5g / cm³, accuracy ±0.01g / cm³). When the density deviation exceeds the set value ±0.02g / cm³, an abnormal reagent concentration alarm is triggered, reminding operators to replenish or adjust the reagent concentration.

[0052] This invention also includes:

[0053] Nitrogen removal effect prediction and early control module: This module uses formulas Calculate the TN removal rate at different reaction times, where R t TN removal rate at reaction time t (dimensionless, range 0-1), t is reaction time (in min, range 0-30 min), and k is the denitrification reaction rate constant (in units of t). The value ranges from 0.02 to 0.05. Adjust according to water temperature; when water temperature is ≥25℃, k is taken as 0.05. C represents the real-time TN concentration during the reaction process (in mg / L, obtained by the TN sensor of the mixing reaction module), and C0 represents the influent TN concentration (in mg / L, obtained by the TN sensor of the influent regulation module). This formula can be used to predict the final effluent TN concentration under the current reaction conditions. When the predicted effluent TN is ≥10 mg / L, the central control system increases the dosage of denitrification agent in advance (the increase ratio is 1.2 times the predicted exceedance) and extends the hydraulic retention time in the slow reaction zone (achieved by reducing the influent flow rate, reducing the current flow rate by 5% each time, with a minimum flow rate of not less than 100 m³ / h), thereby reducing the probability of the final effluent TN exceeding the standard.

[0054] Equipment Maintenance Early Warning Module: This module monitors the operating parameters of key equipment (mixer, metering pump, magnetic separator, online monitoring instrument) in real time. Monitored parameters include operating current (measurement range 0-50A, accuracy ±0.1A), operating temperature (measurement range 0-80℃, accuracy ±1℃), operating time (in hours), and fault codes. An overload warning is triggered when the mixer's operating current exceeds 110% of its rated current or the temperature is ≥70℃. A maintenance warning is triggered when the metering pump's flow rate deviation exceeds the set value by ±5% or the operating time is ≥8000 hours. A repair warning is triggered when the magnetic separator's magnetic field strength deviation exceeds the set value by ±10% or the operating time is ≥10000 hours. A calibration warning is triggered when the online monitoring instrument's data deviation exceeds ±10% for three consecutive tests or its zero-point drift is ≥0.2mg / L. All warning information is displayed and recorded in the central control system and simultaneously pushed to the administrator's mobile phone (via SMS or an app) to remind them to perform maintenance promptly.

[0055] Emergency Response Module: This module activates emergency measures in the event of a sudden system failure (sudden increase in influent flow, interruption of chemical supply, equipment shutdown). When the influent flow exceeds 120% of the design value, the central control system automatically closes some influent valves to control the flow within the design range and opens the emergency overflow pipe of the regulating tank (diameter DN300-DN500, material 316L stainless steel). When the liquid level in any chemical storage tank is below 10% and replenishment is not timely, the emergency chemical dosing tank (volume 1-5m³, storing backup chemicals) is activated, while the treatment flow is reduced to 50% of the design value. When the magnetic seed recovery device stops, the magnetic seed addition pump is turned off to stop the addition of magnetic seeds. At the same time, the sludge from the clarifier is directly discharged to the sludge treatment system to reduce the accumulation of magnetic seeds in the clarifier. When the online monitoring instrument shows that the water index is seriously out of standard (TN≥15mg / L or TP≥1.0mg / L), the effluent return valve (diameter DN200-DN400, material 316L stainless steel) is opened to return the outflowing water to the inflow regulating module for reprocessing. All operations during the emergency handling process are recorded in the central control system. After the fault is cleared, the system automatically returns to normal operation mode.

[0056] A specific implementation method of a magnetic loading clarification system for deep nitrogen and phosphorus removal in wastewater treatment plant effluent:

[0057] Example 1: A magnetic loading clarification system for deep denitrification and phosphorus removal of effluent from urban wastewater treatment plants.

[0058] This embodiment focuses on a municipal wastewater treatment plant with a daily average discharge of 5000 m³ / d of secondary treated effluent. The influent water quality indicators are TN 18-22 mg / L, TP 1.0-1.3 mg / L, and COD 35-45 mg / L, requiring treatment to meet the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002) (TN≤15 mg / L, TP≤0.5 mg / L). After applying the system of this invention, a single system has a treatment capacity of 200 m³ / h and operates continuously for 24 hours. The specific implementation process is as follows:

[0059] I. System Module Deployment and Parameter Setting

[0060] Inlet water regulation module: The effective volume of the regulation tank is 400m³ (designed for a 2-hour hydraulic retention time, 200m³ / h × 2h = 400m³). The tank body is made of reinforced concrete with a 2.5mm thick epoxy resin anti-corrosion layer on the inner wall. It is equipped with two vertical agitators (one in use and one on standby), with a speed of 70r / min and a stirring power of 0.8kW / 100m³ (3.2kW per unit). Submersible level sensors (measuring range 0-4m, accuracy ±0.01m) and electromagnetic flow sensors (measuring range 150-250m³ / h, accuracy ±1%) are installed on the side walls. The inlet valve is a DN400 electric butterfly valve with a 2.5s opening and closing response time. Through PLC linkage with the flow sensor, the inlet flow rate is stably controlled at 200m³ / h ±5m³ / h.

[0061] Magnetic seed and reagent dosing module: The magnetic seed uses 80nm nanometers. The magnetic seed dissolution and dispersion tank has a saturation magnetization of 90 emu / g and a purity of 99.5%. The tank has a volume of 2 m³, a jacketed heating device set at 28℃ with a heating power of 3 kW, and is equipped with a 20 kHz ultrasonic disperser (400 W power) and a paddle-type mechanical stirrer (0.8 m diameter, 100 r / min speed, 1.5 kW power). The magnetic seed suspension concentration is controlled at 80 g / L. A screw metering pump (flow range 0-80 L / h, accuracy ±2%) is used for dosing. The dosing ratio is set at 5 times the TP concentration in the effluent (6 mg / L when TP = 1.2 mg / L). In the reagent dosing module, the denitrification agent is a 25% hydroxyl radical oxidant. and The molar ratio is 3:1), and the flow range of the plunger metering pump is 0-40 L / h; the phosphorus removal agent is 12% PAC (A The content is 31%, the flow rate of the diaphragm metering pump is 0-80L / h; the alkalinity is adjusted with 20% NaOH, the flow rate of the screw metering pump is 0-20L / h, and the pH of the reaction system is set to 7.0±0.2.

[0062] Mixing and Clarification Module: The rapid mixing zone uses a DN300, 1.5m long 316L stainless steel pipe mixer with 3 sets of built-in spiral blades, a hydraulic residence time of 15s, and a stirring intensity of [missing information]. The slow reaction zone is a plug-flow reaction tank (effective volume 300m³, 200m³ / h × 1.5h = 300m³), equipped with 3 horizontal stirrers (speed 30r / min, power 1.5kW / 100m³), and a set of pH sensors (measurement range 6-9, accuracy ±0.1) and ORP sensors (measurement range -200-800mV, accuracy ±5mV) are installed every 5m along the flow. The magnetically loaded clarifier has a diameter of 8m and an effective water depth of 3.5m. The top annular inlet distribution channel is 0.25m wide and 0.4m deep. The perforated pipe has a diameter of 12mm and a spacing of 80mm. The inclined tube sedimentation zone is filled with 50mm hexagonal polypropylene inclined tubes, 1.2m long, with an inclination angle of 60° and a packing layer height of 1.1m. The supporting grid is made of 316L stainless steel (50×50mm mesh). The bottom permanent magnet separation device uses neodymium iron boron permanent magnets with a magnetic field strength of 0.4T, a separation zone height of 0.6m, and a hydraulic retention time of 8min. The surrounding triangular weir is 0.15m high with a horizontal error of ≤1mm at the top. The outlet channel is 1.2m wide and contains a 50μm pore size 316L stainless steel filter screen (filtration area 1.5m²).

[0063] II. Core Technological Processes and Formula Applications

[0064] Precise dosing of phosphorus removal agents: The precise dosing control module for phosphorus removal agents calls upon the TP sensor data from the influent regulating module. With traffic data (Q w =200m³ / h), set the target TP concentration C in the effluent. e =0.2mg / L, effluent turbidity 18NTU, take k=1.3; substitute into formula Q p =k×(C0-C e )×Q w Q is calculated p =1.3×(1.2-0.2)×200=260L / h; Since the PAC concentration is 12%, the actual dosage needs to be converted to the pure reagent dosage (260L / h×12%=31.2L / h pure PAC). The metering pump is operated at a flow rate of 31.2L / h, and the response time is adjusted to 0.8s to ensure stable TP removal effect.

[0065] Magnetic seed recovery efficiency assessment: The dynamic assessment module for magnetic seed recovery efficiency is set to assessment periods t0=9:00 and t1=10:00 (60 min). Real-time data is obtained for the following parameters: magnetic seed return flow rate Qr=40 L / h, return concentration Cr=150 g / L (150000 mg / L), demagnetized sludge flow rate Qw=15 m³ / h, sludge magnetic seed concentration Cw=8 mg / L, magnetic seed addition flow rate Qm=15 L / h (calculated based on the addition rate: 200 m³ / h × 6 mg / L = 1200 g / h; combined with the magnetic seed suspension concentration of 80 g / L, Qm=1200 g / h ÷ 80 g / L = 15 L / h), and addition concentration Cm=80000 mg / L. The magnetic seed recovery efficiency formula is defined as "the ratio of the amount of recyclable magnetic seed recovered per unit time to the amount of fresh magnetic seed added." (Since the parameters are stable within the evaluation period, the integral can be simplified to a calculation per unit time). Substituting the data, the calculation is as follows: Magnetic seed return rate per unit time: 40L / h × 150g / L = 6000g / h; Magnetic seed loss rate per unit time: 15m³ / h × 8mg / L = 0.012g / L × 15000L / h = 120g / h; Fresh magnetic seed addition rate per unit time: 15L / h × 80g / L = 1200g / h; Recovery efficiency: It needs to be clarified here: Qr×Cr includes the amount of circulating magnetic seed. In actual engineering, the core focus of the recovery rate is on "controlling the loss of fresh magnetic seed", that is, the loss rate = (amount of magnetic seed lost in sludge ÷ amount of fresh magnetic seed added) × 100% = 120 ÷ 1200 × 100% = 10%, corresponding to a fresh magnetic seed recovery rate of 1 - 10% = 90%. The central control system determines that there is no need to adjust the magnetic field strength based on the preset threshold of loss rate ≤ 10%.

[0066] Nitrogen removal effect prediction and control: The nitrogen removal effect prediction and early control module obtains the influent TN concentration C0 = 20 mg / L, water temperature 23℃, and takes k = 0.03. The reaction time is t = 20 min; substituting into the formula... The integral calculation yields Assuming C changes with reaction time as C = 20e^-0.03t, then the integral = =0.6×[(-1 / 0.06)e^-0.06×20+1 / 0.06]=0.6×(16.666×(1-0.3012))=0.6×11.647=6.988mg / L; R t=1-6.988 / 20=0.6506 (65.06%), the predicted effluent TN=20×(1-0.6506)=6.988mg / L≤15mg / L, no adjustment of reagent is required; when the influent TN rises to 23mg / L the next day, the predicted effluent TN=23×(1-0.6506)=8.04mg / L, which still meets the standard, and the system maintains stable operation.

[0067] III. Operational Results and Data Representation

[0068] Table 1: Comparison of water quality and operating costs before and after effluent treatment at an urban wastewater treatment plant in Example 1:

[0069] index Before treatment (mg / L) After treatment (mg / L) Removal rate (%) Operating cost (RMB / ton of water) TN 20±2 7±1 65-75 - TP 1.2±0.1 0.2±0.05 83-88 - COD 40±5 18±3 50-58 - Drug cost - - - 0.32 Magnetic seed replenishment cost - - - 0.08 Electricity bill - - - 0.15 Total operating costs - - - 0.55

[0070] Table 1 shows the treatment efficiency and economy of the system in this embodiment: the treated TN, TP, and COD are all consistently better than the Class A standard, with a TP removal rate exceeding 83%, mainly due to the precise dosing of phosphorus removal agents and the efficient flocculation of magnetic seeds; the denitrification efficiency is over 65%, thanks to the high activity of the hydroxyl radical oxidant at room temperature and the adaptive regulation of the reaction process. In terms of operating costs, the total cost is 0.55 yuan / ton of water, lower than the traditional biological denitrification + chemical phosphorus removal process (approximately 0.8 yuan / ton of water). The magnetic seed replenishment cost is only 0.08 yuan / ton of water, demonstrating the advantage of high magnetic seed recovery rate; the agent cost is 0.32 yuan / ton of water, with reduced waste due to precise dosing, and the overall system meets the low-cost operation requirements of urban wastewater treatment plants. During the emergency test, the influent flow rate suddenly increased to 250 m³ / h (125% over the design). Within 10 seconds, the emergency treatment module closed some influent valves, opened the emergency overflow pipe, and reduced the dosage of the chemical by 10%. The effluent TP briefly rose to 0.4 mg / L and then quickly dropped back down, without serious exceeding the standard, thus verifying the system's emergency response capability.

[0071] Example 2: Magnetic loading clarification system for deep denitrification and phosphorus removal of effluent from industrial park wastewater treatment plants.

[0072] This embodiment addresses a wastewater treatment plant in a chemical industrial park, with a daily effluent discharge of 4000 m³ / d containing small amounts of industrial pollutants. The influent water quality is TN 20-25 mg / L, TP 1.3-1.5 mg / L, and COD 45-55 mg / L, requiring treatment to meet local discharge standards stricter than Class A (TN ≤ 10 mg / L, TP ≤ 0.3 mg / L). The system of this invention has a single-unit treatment capacity of 160 m³ / h. The specific implementation process is as follows:

[0073] I. System Module Deployment and Parameter Setting

[0074] Influent regulation and pretreatment module: The regulating tank has an effective volume of 320 m³ (160 m³ / h × 2h), is made of reinforced concrete, and has a 3 mm thick anti-corrosion layer; it is equipped with two vertical agitators (65 r / min, 0.9 kW / 100 m³); it is equipped with a level sensor (0-5 m, ±0.01 m) and an electromagnetic flow meter (120-200 m³ / h, ±1%); the influent valve is a DN350 electric butterfly valve (response time 2.8 s), and the flow rate is stable at 160 m³ / h. Because the effluent contains a small amount of suspended solids, a bar screen pretreatment unit (5 mm spacing, 316L stainless steel) is added to prevent clogging of subsequent pipelines.

[0075] Magnetic seed and reagent dosing module: 60nm magnetic seed is selected. (Saturation magnetization 95 emu / g, purity 99.8%), dispersion tank volume 1.5 m³ (heating temperature 27℃, power 2.5 kW), ultrasonic disperser (30 kHz, 450 W) and paddle stirrer (diameter 0.6 m, speed 110 r / min, power 1.2 kW); magnetic seed suspension concentration 70 g / L, dosage ratio 8 times TP (when TP=1.5 mg / L, dosage 12 mg / L), screw metering pump flow rate 0-60 L / h. For the reagents, the denitrification agent is 28% hydroxyl radical oxidant (…). and (Molar ratio 4:1), plunger metering pump 0-50L / h; phosphorus removal agent is 15% PAC ( 32% concentration), diaphragm metering pump 0-70L / h; NaOH concentration 20%, screw metering pump 0-18L / h, pH control 6.8±0.2.

[0076] Mixing and clarification module: The rapid mixing zone is a DN250, 1.2m long pipe mixer (316L stainless steel) with a hydraulic retention time of 12s. The slow reaction zone has an effective volume of 240 m³ (160 m³ / h × 1.5 h), four horizontal stirrers (25 r / min, 1.8 kW / 100 m³), ​​and four pH / ORP sensors along the flow path. The magnetically loaded clarifier has a diameter of 7 m, an effective water depth of 3.2 m, an inlet distribution channel width of 0.22 m, and perforated pipes with a diameter of 10 mm and a spacing of 70 mm. The inclined tube packing layer has a height of 1.0 m (50 mm polypropylene inclined tubes). The permanent magnet separation device has a magnetic field strength of 0.45 T, a separation height of 0.7 m, and a hydraulic retention time of 9 min. The effluent weir is a triangular weir (0.15 m high), and the effluent channel filter screen is 50 μm (1.2 m² area).

[0077] II. Core Process and Formula Application: Intelligent Control of Sludge Discharge from Clarifier: The intelligent control module for sludge discharge from the clarifier obtains the following parameters: sludge interface height in the sludge hopper is 1.1m (≥1.0m), sludge concentration is 3200mg / L (≥3000mg / L), effective sludge hopper volume V=5m³ (diameter 7m, cone angle 60°, height 1.2m), target concentration Cs=1800mg / L, and sludge pump flow rate Q=30m³ / h; these parameters are then substituted into the formula... Calculated The central control system activated the sludge pump to discharge sludge for 4.5 minutes. After discharge, the sludge concentration dropped to 1780 mg / L, meeting the target and preventing excessive loss of magnetic seeds. Magnetic seed dispersion and particle size control: The online particle size analyzer of the magnetic seed dispersion enhancement module monitored every 10 minutes. In one monitoring, the proportion of magnetic seeds with a particle size ≥150 nm was 12% (≥10%). The central control system automatically increased the power of the ultrasonic disperser from 450W to 500W (maximum power) and extended the stirring time from 15 minutes to 20 minutes. After 30 minutes, the measurement was repeated, and the proportion of particles with a particle size ≥150 nm dropped to 7%, restoring normal parameters and ensuring that the magnetic seeds and pollutants were fully combined, increasing the floc settling speed by 20%. Adaptive regulation of the denitrification reaction: The ORP sensor in the mixed reaction module monitored a value of 180mV (<200mV), indicating insufficient denitrification reagent. The central control system increased the dosage of the oxidant metering pump by 5% (from 30L / h to 31.5L / h). After 5 minutes, the ORP rose to 220mV and stabilized in the 200-400mV range. At the same time, the pH dropped to 6.4 (<6.5), and the NaOH metering pump increased the dosage by 10% (from 8L / h to 8.8L / h), and the pH rose back to 6.8, ensuring that the denitrification reaction proceeded under optimal conditions.

[0078] III. Operational Results and Data Representation

[0079] Table 2: Key Indicators and System Stability Data of Wastewater Treatment Plant in Industrial Park, Example 2:

[0080] index Design value Actual operating value Compliance status Fluctuation range TN (mg / L) of effluent ≤10 8.5±1.2 Meets standards ±14.1% effluent TP (mg / L) ≤0.3 0.25±0.04 Meets standards ±16.0% Magnetic seed recovery rate (%) ≥90 92±2.5 Meets standards ±2.7% Dosage accuracy (%) ±2 ±1.8 Meets standards ±10.0% Trouble-free uptime (h) ≥720 850 Meets standards -

[0081] Table 2 data verifies the adaptability and stability of the system in this embodiment for industrial park effluent: effluent TN and TP both consistently meet standards, with fluctuations controlled within ±16%. This is primarily due to the adaptive regulation of the denitrification reaction and precise dosing of phosphorus removal agents, demonstrating strong ability to cope with fluctuations in industrial effluent quality. The magnetic seed recovery rate exceeds 92%, thanks to dynamic evaluation of magnetic seed recovery efficiency and adjustment of magnetic field strength, reducing magnetic seed replenishment costs. Agent dosing accuracy is ±1.8%, avoiding agent waste or insufficient effectiveness due to water quality fluctuations. The equipment has a fault-free operating time of 850 hours, exceeding the design value by 18%, demonstrating the role of the equipment maintenance early warning module—an overload warning is triggered when the agitator current exceeds the rated value by 110% (11A / 10A), prompting timely cleaning of entangled materials on the agitator blades and preventing downtime. During the emergency test, the PAC agent storage tank level dropped to 8% (<10%). The emergency treatment module activated the 1m³ emergency agent tank and simultaneously reduced the treatment flow rate to 80m³ / h. The effluent TP rose to 0.29mg / L (still meeting the standard). After replenishing the agent, the system returned to normal, verifying the system's ability to cope with agent supply interruptions.

[0082] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant, characterized in that, Comprising: Water inlet adjustment module: equipped with vertical stirrer in the pool, liquid level sensor and flow sensor installed on the side wall of the pool body, water inlet valve controlled by sensor signal linkage to control water inlet flow, pool material adjusted by reinforced concrete, inner wall treated by epoxy resin anticorrosion; Magnetic seed adding module: choose nanometer Magnetic seed, equipped with magnetic seed dissolution and dispersion tank, ultrasonic disperser installed in the tank to make the magnetic seed dispersed uniformly, the concentration of magnetic seed suspension after dispersion is controlled at 50-100g / L, screw metering pump is used for adding equipment, the adding amount is dynamically adjusted according to the tail water TP concentration, the adding ratio is 5 times of the tail water TP concentration, stainless steel material is used for adding pipeline, electromagnetic flowmeter is installed on the pipeline to monitor the adding flow in real time; Medicine adding module: including denitrification medicine adding unit, phosphorus removal medicine adding unit and alkalinity adjusting unit, denitrification medicine selected from 20-30% concentration of hydroxyl radical oxidant, adding equipment for plunger metering pump, adding amount calculated according to TN removal demand of tail water, 2-5 mg / L oxidant added for each 1 mg / L TN removed; phosphorus removal medicine selected from 10-15% concentration of polyaluminum chloride, adding equipment for diaphragm metering pump; alkalinity adjusting unit selected from 20% concentration of NaOH solution, adding equipment for screw metering pump, pH of reaction system controlled at 6.5-7.5; each medicine adding pipeline is equipped with Y-type filter and pressure sensor, liquid level meter installed on medicine storage tank; Mixing reaction module: divided into fast mixing zone and slow reaction zone, fast mixing zone adopts pipeline mixer, hydraulic retention time 10-20s, stirring intensity , the rapid mixing of medicament, magnetic seed and tail water is realized by built-in spiral blade; the slow reaction zone is plug flow reaction tank, the effective volume of single tank is 100-500m³, the hydraulic retention time is 15-30min, horizontal stirrer is installed in the tank, the stirring intensity , 5 groups of pH sensors and ORP sensors are installed along the reaction tank, the sensor data is transmitted to the central control system in real time, and the dynamic adjustment of medicament dosage is realized; Magnetic loading clarification module: circular clarifier with central water inlet and peripheral water outlet, water inlet distribution groove arranged on the top of the pool body, water inlet uniformly distributed through perforated pipe; slanted pipe sedimentation zone arranged in the middle of the pool body, slanted pipe made of polypropylene material, support grid arranged below the filler; permanent magnet separation device arranged at the bottom of the pool body, neodymium-iron-boron permanent magnet used; water outlet weir arranged around the pool body, water outlet channel connected behind the water outlet weir, interception filter screen installed in the water outlet channel to intercept non-separated magnetic seeds; Sludge backflow and magnetic seed recovery module: conical hopper arranged at the bottom of the clarifier, sludge pump connected to the bottom of the hopper to transport magnetic sludge to the magnetic seed recovery device; magnetic seed recovery device adopts high gradient magnetic separator, the outlet of the magnetic separator is divided into magnetic seed concentrate and demagnetized sludge, the magnetic seed concentrate is returned to the magnetic seed dissolution and dispersion tank through the backflow pump, and the demagnetized sludge is transported to the sludge treatment system of the sewage treatment plant through the sludge pump; magnetic seed recovery pipeline is equipped with magnetic seed concentration sensor and turbidimeter to monitor the magnetic seed recovery effect in real time; Water outlet monitoring and control module: water outlet buffer tank arranged at the end of the water outlet channel, online monitoring instrument group installed on the buffer tank, including TN online monitoring instrument, TP online monitoring instrument, COD online monitoring instrument and pH online monitoring instrument, monitoring data transmitted to the central control system; when the outlet water TN is greater than or equal to 10 mg / L or the TP is greater than or equal to 0.3 mg / L, the central control system automatically triggers an alarm and adjusts the adding amount of denitrification medicine or phosphorus removal medicine, and the outlet water of the buffer tank is transported to the subsequent treatment unit or discharged through the lifting pump. Magnetic seed recovery efficiency dynamic evaluation module: through the formula Calculate the magnetic seed recovery rate per unit time, wherein is the magnetic seed recovery rate, t0 is the evaluation start time, t1 is the evaluation end time, Q r is the magnetic seed backflow rate, C r is the backflow magnetic seed concentrate concentration, Q w is the demagnetized sludge flow rate, C w is the magnetic seed concentration in demagnetized sludge, Q m is the magnetic seed dosing flow rate, C m is the magnetic seed dosing liquid concentration, when <90%, the central control system automatically increases the magnetic field strength of the high gradient magnetic separator, while reducing the treatment flow rate, until Rises to more than 90%.

2. The magnetic loading clarification system for advanced nitrogen and phosphorus removal of tail water in sewage treatment plant according to claim 1, characterized in that, Also comprising: Q p =k×(C0-C e )×Q w Calculate the real-time dosage of polyaluminum chloride, where Q p The dosage of polyaluminum chloride is given, k is the reagent coefficient, C0 is the influent TP concentration, and C e Q represents the target TP concentration in the effluent. w This refers to the effluent treatment flow rate.

3. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also comprising: Magnetic seed dispersion degree strengthening module: arranged inside the magnetic seed dissolution and dispersion tank, in addition to the original ultrasonic disperser, mechanical stirring device and online particle size analyzer are added, the mechanical stirring realizes the overall mixing of the magnetic seed suspension, and the ultrasonic dispersion breaks the magnetic seed agglomerates; the online particle size analyzer monitors the particle size distribution of the magnetic seed in real time, and when the proportion of the magnetic seed with particle size greater than or equal to 150 nm is greater than or equal to 10%, the central control system automatically increases the power of the ultrasonic disperser and prolongs the stirring time.

4. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also comprising: Reaction process self-adaptive control module: based on the pH and ORP sensor data of the mixed reaction module, dynamically adjust the dosing amount of alkalinity regulator and denitrification agent, when the pH sensor monitoring value < 6.5, the central control system controls the NaOH metering pump to increase the dosing amount, until the pH rises to the interval of 6.5-7.5; when the ORP sensor monitoring value < 200mV, it means that the denitrification agent is insufficient, the central control system controls the hydroxyl radical oxidant metering pump to increase the dosing amount, when the ORP monitoring value > 400mV, reduce the oxidant dosing amount; at the same time, the module adjusts the stirrer speed according to the hydraulic retention time of the slow reaction zone.

5. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also includes: The intelligent control module of the clarifier sludge discharge adjusts the sludge discharge frequency and duration according to the sludge interface height and sludge concentration in the clarifier sludge hopper. The sludge interface instrument and sludge concentration meter are installed in the sludge hopper. When the sludge interface height is greater than or equal to 1.0 m or the sludge concentration is greater than or equal to 3000 mg / L, the central control system starts the sludge pump to discharge sludge. The sludge discharge duration is calculated by the formula T = V / (Q * (C - C s ), wherein T is the sludge discharge duration, V is the effective volume of the sludge hopper, C is the current sludge concentration, C s is the target sludge concentration, and Q is the sludge pump flow rate. The sludge concentration is monitored in real time during the sludge discharge process, and the sludge discharge is automatically stopped when the concentration decreases to C s .

6. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also includes: Medicine stability guarantee module: temperature control and stirring device is equipped for each medicine storage tank, low temperature heating device is installed for denitrification agent storage tank to reduce the crystallization phenomenon of medicine at low temperature; Phosphorus removal agent storage tank is installed with vertical stirrer, which stirs 2 times a day, each time for 30 minutes, to reduce the stratification phenomenon of PAC solution; NaOH storage tank is installed with corrosion-resistant stirrer to ensure uniform concentration; density meter is also installed for each medicine storage tank, when the density deviation exceeds the set value ± 0.02g / cm³, trigger medicine concentration abnormal alarm to remind the operator to supplement or adjust the medicine concentration.

7. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also includes: Denitrification effect prediction and advance control module: by formula The TN removal rate under different reaction times is calculated, wherein R t is the TN removal rate at reaction time t, t is the reaction time, k is the denitrification reaction rate constant, C is the real-time TN concentration during the reaction process, and C0 is the influent TN concentration.

8. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also includes: Equipment maintenance early warning module: real-time monitoring of the operating parameters of the equipment in the system, the monitoring parameters include equipment operating current, operating temperature, operating time and fault code; When the stirrer operating current exceeds 110% of the rated current or the temperature ≥ 70℃, trigger overload warning; when the metering pump flow deviation exceeds the set value ± 5% or the operating time ≥ 8000h, trigger maintenance warning; when the magnetic field strength deviation of the magnetic separator exceeds the set value ± 10% or the operating time ≥ 10000h, trigger maintenance warning; when the online monitor detects 3 consecutive times with a deviation of ± 10% or a zero drift of ≥ 0.2mg / L, trigger calibration warning; all warning information is displayed and recorded in the central control system, and is pushed to the management personnel's mobile terminal to remind maintenance treatment.

9. The magnetic loading clarification system for advanced nitrogen and phosphorus removal from tail water of a sewage treatment plant according to claim 1, characterized in that, Also includes: Emergency treatment module: when the system fails suddenly, start emergency measures, when the water inflow exceeds the design value of 120%, the central control system automatically closes part of the water inlet valve to control the flow within the design range, and opens the emergency overflow pipe of the adjustment tank; when the liquid level of the medicine storage tank is less than 10% and the medicine is not replenished in time, start the emergency medicine dosing tank and reduce the treatment flow to 50% of the design value; when the magnetic seed recovery device stops, close the magnetic seed dosing pump to stop the magnetic seed addition, and directly discharge the sludge in the clarification tank to the sludge treatment system to reduce the accumulation of magnetic seeds in the clarification tank; when the online monitor shows that the effluent indicators exceed the standard, open the effluent backflow valve to return the over-standard effluent to the water inlet adjustment module for reprocessing, all operations during the emergency treatment process are recorded in the central control system, and the system automatically recovers to normal operation mode after troubleshooting.

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