Multi-stage treatment and recycling system and method for smelting wastewater

Abstract

The invention discloses a multi-stage treatment and recycling system and method for smelting wastewater. The system comprises a self-adaptive pretreatment unit, a graded gradient concentration reverse osmosis system, an efficient heavy and impurity removal unit, a concentrated solution reduction unit, a concentrated solution recycling unit and a whole-process intelligent monitoring platform, according to the invention, through the dynamic agent adding and reaction optimization module, based on historical data interaction between the PLC control unit and the whole-process intelligent monitoring platform, the adding proportion of agents such as sodium hydroxide and quicklime can be automatically adjusted according to the water quality fluctuation of raw water; and the problem of medicament waste or insufficient reaction caused by manual regulation lag in the traditional treatment is avoided. The composite filtration and pre-membrane stabilization integrated module is in series operation with an ultrafiltration membrane assembly through a high-density sedimentation tank, and is matched with regular maintenance of an ultrasonic cleaning device, so that the membrane pollution risk of a subsequent graded gradient concentration reverse osmosis system is effectively reduced, and the stable water production efficiency of the membrane assembly in long-term operation is ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field, and particularly relates to a smelting wastewater multi-stage treatment and recycling system and method. BACKGROUND

[0002] Smelting wastewater discharge treatment refers to a process of purifying wastewater generated in a metal smelting process through physical, chemical, biological and other means to reach national or local discharge standards and prevent pollution to water bodies, soil and ecological environment. The smelting wastewater usually contains high-concentration heavy metal ions (such as lead, zinc, cadmium, copper, nickel, etc.), suspended solids, acidic and alkaline substances, sulfides, ammonia nitrogen and organic pollutants, etc., and has the characteristics of strong toxicity, complex composition and great difficulty in treatment. With the increasing strictness of environmental protection regulations and the improvement of public environmental protection awareness, smelting enterprises have continuously increased the attention to wastewater treatment, promoted the development of efficient, low-consumption and resourceful treatment technologies, and provided a strong guarantee for realizing green smelting and sustainable development. With the increasing strictness of environmental protection policies and the urgent needs of the metallurgical industry for green and low-carbon development, wastewater resource utilization and zero discharge have become the key direction for the sustainable development of metallurgical enterprises.

[0003] However, the conventional treatment method in the prior art cannot meet the requirements of recycling and standard discharge, not only causing resource waste, but also putting pressure on the environmental protection standard operation of enterprises. In particular, in the waste heat power generation system and the circulating cooling system, the stability and purity of the supplementary water quality are required to be high. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems, and to provide a smelting wastewater multi-stage treatment and recycling system and method.

[0005] The technical scheme adopted by the present application is as follows: a smelting wastewater multi-stage treatment and recycling system, comprising: a self-adaptive pretreatment unit, a hierarchical gradient concentration reverse osmosis system, a high-efficiency heavy metal and impurity removal unit, a concentrated liquid reduction unit, a concentrated liquid resource utilization unit and a full-process intelligent monitoring platform.

[0006] The self-adaptive pretreatment unit is internally provided with: a dynamic reagent dosing and reaction optimization module, a composite filtration and membrane pre-stabilization integrated module and an intelligent working condition feedback regulation module.

[0007] The effluent end of the composite filtration and membrane pre-stabilization integrated module of the self-adaptive pretreatment unit is connected to the water inlet adjustment module of the hierarchical gradient concentration reverse osmosis system through a pipeline,

[0008] The PLC control unit of the self-adaptive pretreatment unit is bidirectional data interactive with the full-process intelligent monitoring platform through optical fiber communication;

[0009] The concentrated water outlet of the secondary high-pressure reverse osmosis membrane assembly of the hierarchical gradient concentration reverse osmosis system is connected to the pH adjusting tank inlet of the high-efficiency heavy metal and impurity removal unit;

[0010] The outlet of the ion exchange column of the high-efficiency heavy metal and impurity removal unit is linked to the flat-plate membrane distillation assembly feed pump of the concentrated liquid reduction unit through the data acquisition module, and the signal of the medicament concentration sensor of the scale inhibitor storage tank is directly fed back to the dynamic medicament dosing module of the adaptive pretreatment unit.

[0011] The solid phase outlet of the horizontal screw centrifuge of the concentrated liquid reduction unit is connected to the feed inlet of the multi-effect evaporation crystallizer of the concentrated liquid resource utilization unit, and the condensate water pipeline of the steam heat exchanger is connected to the backwashing water source selection system of the adaptive pretreatment unit.

[0012] The sodium chloride crystallizer crystal particle size analyzer of the concentrated liquid resource utilization unit shares data with the calcium and magnesium ion sensor calibration system of the adaptive pretreatment unit through remote monitoring software.

[0013] The optical fiber communication equipment of the whole-process intelligent monitoring platform is connected to the process parameter acquisition points of each unit.

[0014] In a preferred embodiment, the dynamic medicament dosing and reaction optimization module is internally provided with a medicament storage tank group, a high-precision metering pump, a multi-stage reaction stirring tank, a pH and ORP online monitoring probe, a calcium and magnesium ion concentration sensor, and a PLC control unit. The medicament storage tank group is independently stored according to the classification of sodium hydroxide, lime, and sodium carbonate, and is provided with a liquid level meter and a low liquid level alarm device. The metering pump adopts a plunger structure with 0% to 100% stroke adjustment function and is linked in real time with the sensor data. The reaction stirring tank is divided into a rapid mixing zone and a flocculation reaction zone, which are respectively provided with a turbine type and a paddle type stirrer. The pH and ORP probe is installed on the outlet pipeline of the reaction tank to realize second-level data acquisition. The calcium and magnesium ion concentration sensor is connected to the flow cell through a sampling pump for continuous monitoring. The PLC control unit integrates a medicament dosing amount adaptive algorithm to dynamically adjust the dosing proportion of each medicament according to real-time water quality parameters.

[0015] In a preferred embodiment, the integrated module for composite filtration and pre-membrane stabilization internally includes a high-density sedimentation tank, a D-type filter, an ultrafiltration membrane module, an ultrasonic cleaning device, a backwash pump, a precision filter, and an effluent water quality monitor. The high-density sedimentation tank has an upward flow structure with a sludge hopper and sludge pump at the bottom. The D-type filter is filled with quartz sand and anthracite filter media and equipped with an air-water backwash system. The ultrafiltration membrane module is an externally pressurized hollow fiber membrane made of PVDF with a pore size of 0.03 μm. The ultrasonic cleaning device is installed below the ultrafiltration membrane module with a 40 kHz transmission frequency and adjustable power. The backwash pump is a horizontal centrifugal pump with a head of 30 m and a flow rate matched to the number of membrane modules. The precision filter cartridge has a pore size of 5 μm and is made of polypropylene. The effluent water quality monitor, including a turbidity meter and an SDI meter, is installed in the ultrafiltration permeate pipeline.

[0016] In a preferred embodiment, the intelligent operating condition feedback regulation module internally includes an SDI online detector, a flow sensor, a pressure transmitter, a data acquisition module, an adaptive control algorithm module, and an actuator drive unit. The SDI online detector continuously measures the pollution index through a constant pressure filtration device and an automatic timing system. The flow sensor is electromagnetically mounted on the inlet pipe of the filtration system. The pressure transmitters are respectively installed at the inlet and outlet of the filter tank and the concentrate end of the ultrafiltration membrane module. The data acquisition module communicates with each sensor using the Modbus protocol with a sampling frequency of 1Hz. The adaptive control algorithm module incorporates a composite regulation logic based on PID and fuzzy control. The actuator drive unit includes a frequency converter and an electric regulating valve to control the filter pump speed and the backwash valve opening, respectively.

[0017] The intelligent operating condition feedback adjustment module is based on real-time monitoring data of the effluent SDI (Soil Degradation Index). The system achieves adaptive adjustment of the filtration flow rate and backwash cycle through a dynamic coupling model of water quality parameters and process parameters. The specific process is as follows: First, the SDI value is acquired through an online sensor (collected every 15 minutes). When SDI > 3, a first-level adjustment mechanism is triggered—the filtration flow rate is reduced proportionally to the deviation, and simultaneously, an SDI trend prediction model (based on the SDI change rate of the past three samples) is activated. If it is predicted that the SDI will continue to rise within the next 5 minutes (change rate > 0.2 units / min), a second-level adjustment is triggered, simultaneously shortening the backwash cycle and increasing the backwash water flow rate. When SDI ≤ 2.5 and the change rate tends to stabilize (absolute value < 0.05 units / min), the system gradually restores the baseline flow rate and backwash cycle to avoid energy waste caused by over-adjustment.

[0018] The dynamic correction formula for the filtration flow rate is:

[0019]

[0020] In the formula:

[0021] V(k) represents the current time filtering flow rate (m / h), the value range is 60% ~ 100% of the reference flow rate;

[0022] V0 reference flow rate (design value, take 10 m / h);

[0023] α represents the SDI deviation adjustment coefficient (empirical value 0.35), which is positively correlated with the SDI over-standard degree;

[0024] SDI(k) represents the current sampling time of the pollution index (unit: 1 / 15min);

[0025] SDI target represents the target control value (3.0);

[0026] β represents the SDI change rate weight coefficient (empirical value 0.2), which is used for trend prediction;

[0027] represents the SDI real-time change rate (units / min), which is calculated by the first-order difference of the previous 3 sampling data;

[0028] The backwashing cycle adaptive adjustment formula is:

[0029]

[0030] In the formula:

[0031] T backwash represents the current backwashing cycle (h), which is not less than 2h;

[0032] T0 represents the reference backwashing cycle (design value, take 8h);

[0033] γ represents the cumulative deviation amplification coefficient (empirical value 0.12);

[0034] represents the SDI deviation integral from the completion of the last backwashing to the current time (reflecting the cumulative pollution degree).

[0035] By coupling the real-time value, change rate and cumulative deviation of SDI, the "prediction-prevention" type adjustment is realized: when the SDI approaches the threshold value, the speed is reduced in advance to avoid membrane pollution deterioration; when the pollution accumulates to a certain degree, the backwashing cycle is actively shortened, solving the problem of shortening of membrane life caused by "lagging adjustment" in traditional fixed parameter control. The introduction of exponential function and integral term in the formula makes the adjustment process smooth and anti-interference, which meets the scene demand of high-salt high-hardness wastewater with large quality fluctuation.

[0036] In a preferred embodiment, the internal of the staged gradient concentration reverse osmosis system is provided with a first reverse osmosis membrane assembly, a second high-pressure reverse osmosis membrane assembly, a high-pressure feed pump, an energy recovery device, a security filter, a pressure sensor and a flow regulating valve. The first reverse osmosis membrane assembly adopts a 4:2 array of composite membrane elements arranged in a brackish water type, and the second high-pressure reverse osmosis membrane assembly selects seawater desalination membrane elements configured in series in a 3:1 configuration. The high-pressure feed pump is a horizontal multi-stage centrifugal pump designed with a head of 2.0 MPa. The energy recovery device is connected to the second concentrated water outlet pipe using a PX pressure exchanger. The security filter has a filter core aperture of 5 μm and is made of polypropylene. The pressure sensor is installed in the inlet and outlet pipes of each membrane assembly. The flow regulating valve controls the concentrated water circulation ratio using a pneumatic adjustment method.

[0037] In a preferred embodiment, the internal of the high-efficiency heavy metal and impurity removal unit is provided with a sodium sulfide dosing tank, a DTCR chelating agent dosing pump, an ion exchange column, a precision filter, a scale inhibitor storage tank, an electromagnetic scale inhibitor and a pH adjusting tank. The sodium sulfide dosing tank has a volume of 500 L and is provided with a mechanical stirring device. The DTCR chelating agent dosing pump is a diaphragm metering pump with a flow range of 0-50 L / h. The ion exchange column is filled with D401 type chelating resin with a diameter of 800 mm and a height of 2500 mm. The precision filter has a filter core made of 316L stainless steel and is a folded polypropylene. The scale inhibitor storage tank is connected to the dosing pump through a PVC pipeline. The electromagnetic scale inhibitor is installed in the reverse osmosis concentrated water inlet pipeline with a frequency of 20-50 kHz. The pH adjusting tank is provided with a pH electrode and an automatic acid adding device.

[0038] In a preferred embodiment, the internal of the concentrated liquid reduction unit is provided with a flat sheet membrane distillation assembly, a steam heat exchanger, a vacuum pump, a feed pump, a condensate water collection tank, a temperature sensor and a vacuum gauge. The flat sheet membrane distillation assembly has a PTFE membrane with an effective area of 10 m 2 , the steam heat exchanger is a plate heat exchanger with a heat exchange area of 5 m 2 , the vacuum pump is a water ring type with a vacuum range of -0.09 to -0.07 MPa, the feed pump is a stainless steel centrifugal pump with a head of 25 m, the condensate water collection tank is provided with a liquid level meter and a drain electromagnetic valve, the temperature sensor is installed in the inlet and outlet pipes of the membrane assembly, and the vacuum gauge is a pointer type installed in the outlet pipeline of the vacuum pump.

[0039] In a preferred embodiment, the internal of the concentrated liquid resource unit is provided with a multi-effect evaporation crystallizer, a horizontal spiral centrifuge, a hot air dryer, a sodium chloride crystallizer, a sodium sulfate precipitation tank, a screw conveyor and a salt storage bin. The multi-effect evaporation crystallizer adopts a three-effect countercurrent process with a heating area of 50 m 2The horizontal screw centrifuge has a drum diameter of 450mm and a length of 1800mm; the hot air dryer has an inlet temperature of 120℃ and a processing capacity of 500kg / h; the sodium chloride crystallizer is equipped with a stirring device and a density sensor; and the sodium sulfate precipitation tank is an inclined tube precipitation tank with a surface loading of 1.5m. 3 / m 2 The screw conveyor is made of 304 stainless steel and has a conveying capacity of 2m³. 3 / h, effective volume of salt storage silo 100m³ 3 Configure level gauges and dust removal devices.

[0040] In a preferred embodiment, the intelligent monitoring platform for the entire process includes a main control cabinet, an industrial touchscreen, a data acquisition module, fiber optic communication equipment, a UPS power supply, alarm indicator lights, and remote monitoring software. The main control cabinet uses a GGD-type cabinet to mount a Siemens S7-1200 PLC. The industrial touchscreen is a 15-inch color LCD display. The data acquisition module supports 8 analog inputs and 4 digital outputs. The fiber optic communication equipment enables data transmission between each unit and the central control room. The UPS power supply has a capacity of 10kVA and a backup time of 30 minutes. The alarm indicator lights use red, yellow, and green to distinguish between fault warnings and normal states. The remote monitoring software supports web access and historical data query functions.

[0041] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0042] 1. This invention demonstrates significant technical advantages through the modular design of the adaptive pretreatment unit and the collaborative control of the entire process. The dynamic reagent dosing and reaction optimization module, relying on historical data interaction between the PLC control unit and the intelligent monitoring platform, can automatically adjust the dosage ratios of reagents such as sodium hydroxide and quicklime according to fluctuations in raw water quality, avoiding the problems of reagent waste or incomplete reaction caused by manual adjustment delays in traditional treatment. The integrated module for composite filtration and pre-membrane stabilization, through the series operation of a high-density sedimentation tank and ultrafiltration membrane modules, combined with regular maintenance by an ultrasonic cleaning device, effectively reduces the risk of membrane fouling in the subsequent graded gradient concentration reverse osmosis system, ensuring stable water production efficiency of the membrane modules during long-term operation.

[0043] 2. In this invention, the sludge from the adaptive pretreatment unit is directly transported to the concentrate reduction unit via pipeline, reducing the infrastructure costs of separate sludge treatment; the energy recovery device of the graded gradient concentration reverse osmosis system feeds back the residual pressure of the secondary concentrate to the primary feedwater system, significantly reducing the energy consumption of the high-pressure feedwater pump. The parameter linkage between the high-efficiency heavy metal removal and impurity removal unit and the concentrate resource recovery unit, such as adjusting the crystallizer operating parameters based on the heavy metal concentration difference signal, not only improves the heavy metal removal efficiency but also achieves the resource recovery of sodium chloride and sodium sulfate through salt separation treatment, reducing the pressure on solid waste disposal.

[0044] 3. In this invention, the real-time data interaction between the full-process intelligent monitoring platform and the adaptive pretreatment unit constructs a stable and reliable operation guarantee system. The intelligent operating condition feedback and adjustment module dynamically adjusts the filtration flow rate and backwash cycle based on a comparative analysis of the SDI value of the ultrafiltration permeate and the fouling index of the flat-plate membrane distillation component, avoiding misjudgments that may occur due to monitoring a single indicator. Key parameters of each unit are shared through fiber optic communication equipment. When the salt storage tank level in the concentrate resource recovery unit reaches the threshold, the steam output of the evaporator crystallizer is automatically reduced, and feedback is simultaneously sent to the pretreatment unit to adjust the reagent dosing strategy, forming a cross-unit collaborative optimization closed loop. This highly integrated intelligent control not only reduces the intensity of manual operation but also ensures the long-term stability of the system and the reliability of the effluent quality through early warning and automatic adjustment of abnormal operating conditions. Attached Figure Description

[0045] Fig. 1 This is an overall system block diagram of the present invention;

[0046] Fig. 2 This is a block diagram of the adaptive preprocessing unit system in this invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0048] Reference Figs. 1-2 ,

[0049] Example:

[0050] A multi-stage treatment and reuse system for smelting wastewater includes: an adaptive pretreatment unit, a graded gradient concentration reverse osmosis system, a high-efficiency heavy metal removal and impurity removal unit, a concentrate reduction unit, a concentrate resource utilization unit, and a full-process intelligent monitoring platform.

[0051] The adaptive pretreatment unit is internally equipped with: a dynamic reagent dosing and reaction optimization module, a composite filtration and pre-membrane stabilization integrated module, and an intelligent operating condition feedback adjustment module.

[0052] The adaptive pretreatment unit is internally equipped with: a dynamic reagent addition and reaction optimization module, a composite filtration and pre-membrane stabilization integrated module, and an intelligent operating condition feedback and adjustment module.

[0053] The effluent end of the adaptive pretreatment unit's integrated filtration and pre-membrane stabilization module is connected via a pipeline to the feed water regulation module of the graded gradient concentration reverse osmosis system.

[0054] The PLC control unit of the adaptive preprocessing unit interacts bidirectionally with the full-process intelligent monitoring platform via fiber optic communication.

[0055] The concentrate outlet of the secondary high-pressure reverse osmosis membrane module in the graded gradient concentration reverse osmosis system is connected to the inlet of the pH adjustment tank of the high-efficiency gravity and impurity removal unit;

[0056] The outlet of the ion exchange column of the high-efficiency heavy removal and impurity removal unit is linked to the feed pump of the flat membrane distillation component of the concentrate reduction unit through the data acquisition module. The reagent concentration sensor signal of the scale inhibitor storage tank is directly fed back to the dynamic reagent dosing module of the adaptive pretreatment unit.

[0057] The solid phase outlet of the horizontal screw centrifuge in the concentrate reduction unit is connected to the feed inlet of the multi-effect evaporator crystallizer in the concentrate resource utilization unit, and the condensate pipeline of the steam heat exchanger is connected to the backwash water source selection system of the adaptive pretreatment unit.

[0058] The sodium chloride crystallizer particle size analyzer in the concentrate resource utilization unit shares data with the calcium and magnesium ion sensor calibration system in the adaptive pretreatment unit through remote monitoring software;

[0059] The fiber optic communication equipment of the full-process intelligent monitoring platform is connected to the process parameter acquisition points of each unit.

[0060] The dynamic reagent dosing and reaction optimization module internally includes reagent storage tanks, a high-precision metering pump, a multi-stage reaction mixing tank, online pH and ORP monitoring probes, calcium and magnesium ion concentration sensors, and a PLC control unit. The reagent storage tanks are independently categorized for sodium hydroxide, quicklime, and sodium carbonate, and are equipped with level gauges and low-level alarms. The metering pump uses a plunger-type structure with 0%–100% stroke adjustment and real-time linkage with sensor data. The reaction mixing tank is divided into a rapid mixing zone and a flocculation reaction zone, equipped with turbine and paddle agitators respectively. The pH and ORP probes are installed on the reaction tank outlet pipe for second-level data acquisition. The calcium and magnesium ion concentration sensors are continuously monitored via a sampling pump connected to the flow tank. The PLC control unit integrates an adaptive reagent dosing algorithm to dynamically adjust the dosage ratio of each reagent based on real-time water quality parameters.

[0061] The integrated module for composite filtration and pre-membrane stabilization internally includes a high-density sedimentation tank, a D-type filter, an ultrafiltration membrane module, an ultrasonic cleaning device, a backwash pump, a precision filter, and an effluent water quality monitor. The high-density sedimentation tank features an upward flow structure with a sludge hopper and sludge discharge pump at the bottom. The D-type filter is filled with quartz sand and anthracite filter media and equipped with an air-water backwash system. The ultrafiltration membrane module uses an external pressure hollow fiber membrane made of PVDF with a pore size of 0.03μm. The ultrasonic cleaning device is installed below the ultrafiltration membrane module with a 40kHz transmission frequency and adjustable power. The backwash pump is a horizontal centrifugal pump with a head of 30m and a flow rate matched to the number of membrane modules. The precision filter cartridge has a pore size of 5μm and is made of polypropylene. The effluent water quality monitor, including a turbidity meter and an SDI meter, is installed in the ultrafiltration permeate pipeline.

[0062] The intelligent operating condition feedback regulation module internally includes an SDI online monitoring instrument, a flow sensor, a pressure transmitter, a data acquisition module, an adaptive control algorithm module, and an actuator drive unit. The SDI online monitoring instrument continuously measures the pollution index through a constant pressure filtration device and an automatic timing system. The flow sensor is electromagnetically mounted on the inlet pipe of the filtration system. The pressure transmitters are installed at the inlet and outlet of the filter tank and at the concentrate end of the ultrafiltration membrane module. The data acquisition module communicates with each sensor using the Modbus protocol with a sampling frequency of 1Hz. The adaptive control algorithm module incorporates a composite regulation logic based on PID and fuzzy control. The actuator drive unit includes a frequency converter and an electric regulating valve to control the filter pump speed and the backwash valve opening, respectively.

[0063] The intelligent operating condition feedback regulation module is based on real-time monitoring data of the effluent SDI (Soil Degradation Index). The system achieves adaptive adjustment of the filtration flow rate and backwash cycle through a dynamic coupling model of water quality parameters and process parameters. The specific process is as follows: First, the SDI value is acquired through online sensors (collected every 15 minutes). When SDI > 3, a primary regulation mechanism is triggered—the filtration flow rate is reduced proportionally to the deviation, and simultaneously, an SDI trend prediction model (based on the SDI change rate of the past three samples) is activated. If it is predicted that the SDI will continue to rise within the next 5 minutes (change rate > 0.2 units / min), a secondary regulation is triggered, simultaneously shortening the backwash cycle and increasing the backwash water flow rate. When SDI ≤ 2.5 and the change rate tends to stabilize (absolute value < 0.05 units / min), the system gradually restores the baseline flow rate and backwash cycle to avoid energy waste caused by over-regulation.

[0064] The dynamic correction formula for the filtration flow rate is:

[0065]

[0066] In the formula:

[0067] V(k) represents the current filtration flow rate (m / h), and its value ranges from 60% to 100% of the reference flow rate.

[0068] V0 reference flow velocity (design value, taken as 10m / h);

[0069] α represents the SDI deviation adjustment coefficient (empirical value 0.35), which is positively correlated with the degree of SDI exceeding the limit;

[0070] SDI(k) represents the pollution index at the current sampling time (unit: 1 / 15min);

[0071] SDI target This indicates the target control value (3.0);

[0072] β represents the SDI change rate weighting coefficient (empirical value 0.2), used to predict trends;

[0073] The real-time rate of change of SDI (units / min) is calculated by the first difference of the first three sampled data.

[0074] The formula for adaptive adjustment of the backwash cycle is:

[0075]

[0076] In the formula:

[0077] T backwash This indicates the current backwash cycle (h), with a minimum of 2 hours;

[0078] T0 represents the baseline backwashing cycle (design value, taken as 8 hours);

[0079] γ represents the cumulative deviation amplification factor (empirical value 0.12);

[0080] This represents the SDI deviation integral from the last backwash to the current time (reflecting the cumulative contamination level).

[0081] By coupling the real-time value of SDI, its rate of change, and cumulative deviation, a "predictive-prevention" regulation is achieved: when the SDI approaches the threshold, the flow rate is reduced in advance to prevent membrane fouling from worsening; when fouling accumulates to a certain level, the backwash cycle is proactively shortened, solving the problem of shortened membrane life caused by "lag regulation" in traditional fixed parameter control. The introduction of exponential and integral terms in the formula makes the regulation process smooth and anti-interference, meeting the needs of scenarios with large fluctuations in the water quality of high-salt and high-hardness wastewater.

[0082] The graded gradient concentration reverse osmosis system internally includes a primary reverse osmosis membrane module, a secondary high-pressure reverse osmosis membrane module, a high-pressure feed water pump, an energy recovery device, a security filter, pressure sensors, and flow control valves. The primary reverse osmosis membrane module uses brackish water type composite membrane elements arranged in a 4:2 array. The secondary high-pressure reverse osmosis membrane module uses seawater desalination membrane elements configured in a 3:1 series configuration. The high-pressure feed water pump is a horizontal multistage centrifugal pump with a design head of 2.0 MPa. The energy recovery device uses a PX-type pressure exchanger connected to the secondary concentrate outlet pipe. The security filter has a 5μm pore size and is made of polypropylene. Pressure sensors are installed on the inlet and outlet pipes of each membrane module. The flow control valves use pneumatic regulation to control the concentrate circulation ratio.

[0083] The high-efficiency heavy and impurity removal unit is internally equipped with a sodium sulfide dosing tank, a DTCR chelating agent dosing pump, an ion exchange column, a precision filter, a scale inhibitor storage tank, an electromagnetic scale inhibitor, and a pH adjustment tank. The 500L sodium sulfide dosing tank is equipped with a mechanical stirrer. The DTCR chelating agent dosing pump is a diaphragm metering pump with a flow rate range of 0-50L / h. The ion exchange column is filled with D401 type chelating resin with a diameter of 800mm and a height of 2500mm. The precision filter uses 316L stainless steel with a pleated polypropylene filter element. The scale inhibitor storage tank is connected to the dosing pump via PVC piping. The electromagnetic scale inhibitor is installed on the reverse osmosis concentrate inlet pipeline with a frequency of 20-50kHz. The pH adjustment tank is equipped with a pH electrode and an automatic acid addition device.

[0084] The concentrate reduction unit internally includes a flat-plate membrane distillation assembly, a steam heat exchanger, a vacuum pump, a feed pump, a condensate collection tank, a temperature sensor, and a vacuum gauge. The flat-plate membrane distillation assembly uses PTFE membranes with an effective area of ​​10m². 2 The steam heat exchanger is a plate heat exchanger with a heat exchange area of ​​5m². 2 The vacuum pump is a water ring type with a vacuum range of -0.09 to -0.07 MPa. The feed pump is a stainless steel centrifugal pump with a head of 25 m. The condensate collection tank is equipped with a level gauge and a drain solenoid valve. The temperature sensor is installed on the inlet and outlet pipes of the membrane module. The vacuum gauge is a pointer type and is installed on the outlet pipe of the vacuum pump.

[0085] The concentrated liquid resource utilization unit is internally equipped with a multi-effect evaporator crystallizer, a horizontal screw centrifuge, a hot air dryer, a sodium chloride crystallizer, a sodium sulfate precipitation tank, a screw conveyor, and a salt storage bin. The multi-effect evaporator crystallizer uses a triple-effect countercurrent process with a heating area of ​​50m². 2 The horizontal screw centrifuge has a drum diameter of 450mm and a length of 1800mm; the hot air dryer has an inlet temperature of 120℃ and a processing capacity of 500kg / h; the sodium chloride crystallizer is equipped with a stirring device and a density sensor; and the sodium sulfate precipitation tank is an inclined tube precipitation tank with a surface loading of 1.5m. 3 / m 2The screw conveyor is made of 304 stainless steel and has a conveying capacity of 2m³. 3 / h, effective volume of salt storage silo 100m³ 3 Configure level gauges and dust removal devices.

[0086] The end-to-end intelligent monitoring platform includes a main control cabinet, an industrial touchscreen, data acquisition modules, fiber optic communication equipment, a UPS power supply, alarm indicator lights, and remote monitoring software. The main control cabinet uses a GGD-type cabinet to mount a Siemens S7-1200 PLC. The industrial touchscreen is a 15-inch color LCD display. The data acquisition module supports 8 analog inputs and 4 digital outputs. The fiber optic communication equipment enables data transmission between each unit and the central control room. The UPS power supply has a capacity of 10kVA and a backup time of 30 minutes. The alarm indicator lights use red, yellow, and green to distinguish between fault warnings and normal states. The remote monitoring software supports web access and historical data query functions.

[0087] A method for multi-stage treatment and reuse of smelting wastewater, applied to the aforementioned multi-stage treatment and reuse system for smelting wastewater; specifically including the following steps:

[0088] S1: When the adaptive pretreatment unit processes smelting wastewater and it enters the dynamic reagent dosing and reaction optimization module, the PLC control unit first retrieves nearly 72 hours of raw water quality fluctuation data stored in the full-process intelligent monitoring platform and automatically generates initial reagent dosing parameters. The pH value of the reaction mixing tank is transmitted in real time to the feed water adjustment module of the graded gradient concentration reverse osmosis system via fiber optic communication equipment. When the pH deviates from the 6.5-7.5 range, a pressure pre-adjustment command is triggered for the secondary high-pressure reverse osmosis membrane module. The SDI value of the ultrafiltration permeate from the integrated module of composite filtration and pre-membrane stabilization is uploaded to the intelligent operating condition feedback adjustment module every 5 minutes for comparative analysis with the fouling index of the flat-plate membrane distillation module of the concentrate reduction unit. When the deviation exceeds 15%, the enhanced backwashing program of the D-type filter is automatically started.

[0089] S2: The concentrated water flow signal from the first-stage reverse osmosis membrane module in the graded gradient concentration reverse osmosis system is transmitted in real time to the pH adjustment tank of the high-efficiency heavy metal removal and impurity removal unit, serving as a feedforward control parameter for the acid addition unit. The residual pressure utilization rate data of the energy recovery unit is displayed on an industrial touchscreen. When it falls below 85%, an alarm indicator light on the full-process intelligent monitoring platform is triggered, and a fine-tuning command for reagent dosage is sent to the PLC control unit of the adaptive pretreatment unit. The permeate quality data of the second-stage high-pressure reverse osmosis membrane module is linked to the feed pump frequency of the concentrate reduction unit; when the conductivity exceeds 500 μS / cm, the feed rate is automatically reduced.

[0090] S3: The high-efficiency heavy metal removal unit processes the inlet and outlet heavy metal concentration difference of the ion exchange column, which is transmitted to the multi-effect evaporator crystallizer of the concentrate resource utilization unit via a data acquisition module. When the difference exceeds 3 mg / L, the frequency of inclined tube flushing in the sodium sulfate precipitation tank is increased in conjunction with the unit. The reagent concentration signal from the scale inhibitor storage tank is fed back to the dynamic reagent dosing and reaction optimization module of the adaptive pretreatment unit as a correction parameter for the quicklime dosage. The operating power of the electromagnetic scale inhibitor is PID-regulated based on the pressure transmitter data from the full-process intelligent monitoring platform, automatically increasing the power output when the transmembrane pressure difference of the ultrafiltration membrane module increases.

[0091] S4: The concentrate reduction unit transmits the concentrate outlet concentration data from the flat-plate membrane distillation unit to the horizontal screw centrifuge in the concentrate resource utilization unit in real time. When the solid content exceeds 15%, a differential speed adjustment command is triggered on the centrifuge. The condensate hardness data from the steam heat exchanger is fed back to the adaptive pretreatment unit via a communication line powered by a UPS, serving as the basis for selecting the backwash water source for the integrated module of composite filtration and pre-membrane stabilization. The vacuum pump's operating current signal is uploaded to the full-process intelligent monitoring platform, forming a correlation analysis with the regeneration cycle of the ion exchange column in the high-efficiency heavy metal removal and impurity removal unit.

[0092] S5: The crystal particle size distribution data of the sodium chloride crystallizer in the concentrated liquid resource recovery unit is shared with the calcium and magnesium ion concentration sensor calibration system of the adaptive pretreatment unit via remote monitoring software. A sensor calibration alert is triggered when the particle size standard deviation exceeds 0.2 mm. The outlet temperature of the hot air dryer and the inlet temperature of the steam heat exchanger in the concentrated liquid reduction unit form a cascade control, with the temperature deviation controlled within ±2℃. The level gauge signal of the salt storage silo is transmitted to the full-process intelligent monitoring platform. When the silo level reaches 80%, the heating steam output of the multi-effect evaporator crystallizer is automatically reduced.

[0093] S6: The full-process intelligent monitoring platform collects 238 process parameters per second from each unit on the main control cabinet. Among them, 12 key indicators, such as the pH value of the adaptive pretreatment unit, the recovery rate of the graded gradient concentration reverse osmosis system, and the heavy metal removal rate of the high-efficiency heavy metal removal unit, are transmitted to the remote monitoring center via fiber optic communication equipment. The industrial touch screen displays the correlation curves of each unit in real time, such as the correlation analysis between the permeate output of the first-stage reverse osmosis unit and the salt output of the concentrate resource utilization unit. When the overall energy consumption of the system exceeds the threshold, the collaborative optimization program of S1 to S5 is automatically activated, prioritizing the reduction of the vacuum pump power of the concentrate reduction unit and simultaneously adjusting the speed of the high-pressure feed water pump of S2.

[0094] Comparative example (existing traditional processing technology):

[0095] Implementation method: A conventional process of "pretreatment + chemical precipitation + biological treatment + deep filtration" is adopted. Specific steps include:

[0096] Pretreatment: Large suspended solids are removed by bar filtration, water quality is balanced in the equalization tank (pH fluctuation range 6-9), and polyaluminum chloride (PAC) is added manually for coagulation and sedimentation to remove about 60% of suspended solids.

[0097] Chemical precipitation: A fixed amount of lime slurry (pH=10) and sodium sulfide (5g / L) are added to the wastewater to generate hydroxide and sulfide precipitates, which are then separated into sludge by a plate and frame filter press.

[0098] Biological treatment: The activated sludge process is used to degrade organic matter, with an 8-hour retention time in the aeration tank and a 50% sludge return ratio.

[0099] Advanced treatment: Sand filtration + activated carbon filtration removes residual particles, and finally sodium hypochlorite is added for disinfection before discharge. Part of it is recycled for greening (reuse rate <30%).

[0100] The comparison data of the treatment effects are shown in the table below:

[0101]

[0102] Data Explanation:

[0103] Heavy metal removal rate: The invention enhances the targeting of hydroxide / sulfide precipitation through dynamic reagent dosing and composite filtration, Cu 2+ Pb 2+ The removal rates increased by 4.6% and 4.9%, respectively.

[0104] Water reuse rate: The graded gradient concentration reverse osmosis system combined with energy recovery increases the reuse rate from 28.5% to 72.3%, saving approximately 1.5 million tons of water per year (based on a daily treatment capacity of 10,000 tons).

[0105] Sludge reduction: Adaptive pretreatment sludge directly enters the concentrate reduction unit, combined with salt separation and crystallization, reducing sludge volume by 58.3% and avoiding the secondary sludge disposal pressure of traditional processes.

[0106] Energy consumption and cost: The energy recovery device reduces the energy consumption of the high-pressure pump by 40.7%, the dynamic dosing of chemicals saves 20% of lime, and the overall operating cost is reduced by 33.3%.

[0107] in conclusion:

[0108] In summary, this invention demonstrates significant technical advantages through the modular design of the adaptive pretreatment unit and the collaborative control of the entire process. The dynamic reagent dosing and reaction optimization module, relying on historical data interaction between the PLC control unit and the intelligent monitoring platform, can automatically adjust the dosage ratios of reagents such as sodium hydroxide and quicklime based on fluctuations in raw water quality, avoiding the waste of reagents or incomplete reactions caused by manual adjustments in traditional treatment methods. The integrated module for composite filtration and pre-membrane stabilization, through the series operation of a high-density sedimentation tank and ultrafiltration membrane modules, coupled with regular maintenance by an ultrasonic cleaning device, effectively reduces the risk of membrane fouling in the subsequent graded gradient concentration reverse osmosis system, ensuring stable water production efficiency of the membrane modules during long-term operation.

[0109] In this invention, sludge from the adaptive pretreatment unit is directly transported to the concentrate reduction unit via pipeline, reducing the infrastructure costs of separate sludge treatment. The energy recovery device of the graded gradient concentration reverse osmosis system feeds back the residual pressure of the secondary concentrate to the primary feedwater system, significantly reducing the energy consumption of the high-pressure feedwater pump. The parameter linkage between the high-efficiency heavy metal removal and impurity removal unit and the concentrate resource recovery unit, such as adjusting the crystallizer operating parameters based on the heavy metal concentration difference signal, not only improves the heavy metal removal efficiency but also achieves the resource recovery of sodium chloride and sodium sulfate through salt separation treatment, reducing the pressure on solid waste disposal.

[0110] In this invention, a stable and reliable operation guarantee system is constructed through real-time data interaction between the full-process intelligent monitoring platform and the adaptive pretreatment unit. The intelligent operating condition feedback and adjustment module dynamically adjusts the filtration flow rate and backwash cycle based on a comparative analysis of the SDI value of the ultrafiltration permeate and the fouling index of the flat-plate membrane distillation component, avoiding misjudgments that may occur due to monitoring a single indicator. Key parameters of each unit are shared through fiber optic communication equipment. When the salt storage tank level in the concentrate resource recovery unit reaches a threshold, the steam output of the evaporator crystallizer is automatically reduced, and feedback is simultaneously sent to the pretreatment unit to adjust the reagent dosing strategy, forming a cross-unit collaborative optimization closed loop. This highly integrated intelligent control not only reduces the intensity of manual operation but also ensures the long-term stability of the system and the reliability of the effluent quality through early warning and automatic adjustment of abnormal operating conditions.

[0111] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is 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 limitations, 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.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage treatment and reuse system for smelting wastewater, characterized in that: include: Adaptive pretreatment unit, graded gradient concentration reverse osmosis system, high-efficiency heavy and impurity removal unit, concentrate reduction unit, concentrate resource utilization unit, and full-process intelligent monitoring platform; The adaptive pretreatment unit is internally equipped with: a dynamic reagent addition and reaction optimization module, a composite filtration and pre-membrane stabilization integrated module, and an intelligent operating condition feedback and adjustment module. The outlet of the composite filtration and pre-membrane stabilization integrated module of the adaptive pretreatment unit is connected to the feed water regulation module of the graded gradient concentration reverse osmosis system via a pipeline. The PLC control unit of the adaptive preprocessing unit interacts bidirectionally with the full-process intelligent monitoring platform via fiber optic communication. The concentrate outlet of the secondary high-pressure reverse osmosis membrane module of the graded gradient concentration reverse osmosis system is connected to the inlet of the pH adjustment tank of the high-efficiency weight and impurity removal unit. The outlet of the ion exchange column of the high-efficiency heavy removal and impurity removal unit is linked to the feed pump of the flat membrane distillation component of the concentrate reduction unit through the data acquisition module, and the reagent concentration sensor signal of the scale inhibitor storage tank is directly fed back to the dynamic reagent dosing module of the adaptive pretreatment unit. The solid phase outlet of the horizontal screw centrifuge of the concentrate reduction unit is connected to the feed inlet of the multi-effect evaporator crystallizer of the concentrate resource utilization unit, and the condensate pipeline of the steam heat exchanger is connected to the backwash water source selection system of the adaptive pretreatment unit. The sodium chloride crystallizer crystal size analyzer in the concentrated liquid resource utilization unit shares data with the calcium and magnesium ion sensor calibration system of the adaptive pretreatment unit through remote monitoring software. The fiber optic communication equipment of the full-process intelligent monitoring platform is connected to the process parameter acquisition points of each unit.

2. The multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The dynamic reagent dosing and reaction optimization module is internally equipped with a reagent storage tank group, a high-precision metering pump, a multi-stage reaction stirring tank, pH and ORP online monitoring probes, calcium and magnesium ion concentration sensors, and a PLC control unit.

3. The multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The integrated module for composite filtration and pre-membrane stabilization includes a high-density sedimentation tank, a D-type filter, an ultrafiltration membrane module, an ultrasonic cleaning device, a backwash pump, a precision filter, and an effluent water quality monitor.

4. The multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The intelligent operating condition feedback and adjustment module is internally equipped with an SDI online detector, a flow sensor, a pressure transmitter, a data acquisition module, an adaptive control algorithm module, and an actuator drive unit. The dynamic correction formula for the filtration flow rate of the intelligent operating condition feedback adjustment module is as follows: In the formula: V(k) represents the current filtering flow rate, and its value ranges from 60% to 100% of the baseline flow rate; V0 reference flow rate; α represents the SDI deviation adjustment coefficient, which is positively correlated with the degree of SDI exceeding the limit; SDI(k) represents the pollution index at the current sampling time; SDI target Indicates the target control value; β represents the SDI change rate weighting coefficient, used to predict trends; The real-time rate of change of SDI is represented by the first-order difference of the first three sampled data. The adaptive adjustment formula for the overwash cycle of the intelligent operating condition feedback adjustment module is as follows: In the formula: T backwash This indicates the current backwashing cycle, with a minimum of 2 hours; T0 represents the baseline backwash cycle; γ represents the cumulative deviation amplification factor; This represents the integral of the SDI deviation from the time the last backwash was completed to the current time.

5. A multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The graded gradient concentration reverse osmosis system is internally equipped with a primary reverse osmosis membrane module, a secondary high-pressure reverse osmosis membrane module, a high-pressure feed water pump, an energy recovery device, a security filter, a pressure sensor, and a flow regulating valve.

6. The multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The high-efficiency heavy and impurity removal unit is equipped with a sodium sulfide dosing tank, a DTCR chelating agent dosing pump, an ion exchange column, a precision filter, a scale inhibitor storage tank, an electromagnetic scale inhibitor, and a pH adjustment tank.

7. The multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The concentrate reduction unit is internally equipped with a flat-plate membrane distillation assembly, a steam heat exchanger, a vacuum pump, a feed pump, a condensate collection tank, a temperature sensor, and a vacuum gauge.

8. A multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The concentrated liquid resource utilization unit is equipped with a multi-effect evaporator crystallizer, a horizontal screw centrifuge, a hot air dryer, a sodium chloride crystallizer, a sodium sulfate precipitation tank, a screw conveyor, and a salt storage tank.

9. A multi-stage treatment and reuse system for smelting wastewater as described in claim 1, characterized in that: The intelligent monitoring platform for the entire process is internally equipped with a main control cabinet, an industrial touch screen, a data acquisition module, fiber optic communication equipment, a UPS power supply, alarm indicator lights, and remote monitoring software.

10. A method for multi-stage treatment and reuse of smelting wastewater, characterized in that: The method is applied to the multi-stage treatment and reuse system for smelting wastewater as described in any one of claims 1 to 9.

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