A controllable separation-electronic flow regulation wastewater treatment system

Abstract

This invention discloses a controllable, hierarchical separation-electrofluidic wastewater treatment system in the field of high-salt chemical wastewater treatment technology. The system includes a multi-stage membrane separation module, an inorganic salt recovery module, a biological treatment module, a biogas resource recovery module, and a sludge treatment module. Through ultrafiltration, nanofiltration, and reverse osmosis components in the multi-stage membrane separation module, the system precisely separates organic matter from inorganic salts in high-salt chemical wastewater. The inorganic salt recovery module, consisting of a bipolar membrane electrodialysis component and a crystallization tower, forms a bipolar membrane electrodialysis-crystallization coupling system. This system simultaneously recovers acid, alkali, and salt resources during inorganic salt treatment. Organic matter undergoes anaerobic biological treatment with sulfur speciation control through multiple modules, achieving synergistic carbon, nitrogen, and sulfur conversion and producing biogas and elemental sulfur. This effectively solves the problems of resource waste and secondary pollution in traditional treatment methods, providing an innovative technological path for synergistic pollution reduction and carbon reduction in chemical industry wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of high-salt chemical wastewater treatment technology, specifically a controllable graded separation-electron flow-regulated wastewater treatment system. Background Technology

[0002] The chemical industry is a pillar industry of national economic development. However, the large volume of chemical wastewater generated, its high treatment difficulty, and its severe environmental hazards seriously hinder the sustainable development of the chemical industry. Under carbon emission constraints, the coordinated treatment of chemical wastewater for pollution reduction and carbon reduction is a common challenge faced by the global chemical industry. Chemical wastewater is characterized by high salt content, high toxicity, and poor biodegradability, leading to difficulties in substance separation, strong biological inhibition, and long treatment processes. At the same time, chemical wastewater contains substances such as carbon, nitrogen, sulfur, and salts, possessing both pollution and resource attributes. Achieving carbon offsetting through multi-resource recovery is a key breakthrough in solving these common challenges.

[0003] However, existing methods for treating chemical wastewater, when faced with multiple pollutants, cannot achieve controllable graded separation, hindering multi-resource recovery and resulting in high carbon emissions and poor wastewater treatment efficiency. Therefore, this invention aims to achieve multi-resource recovery and carbon emission reduction of chemical wastewater through graded separation, process coupling, and factor synergistic control. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater treatment system with controllable hierarchical separation and electron flow regulation to solve the problems mentioned above, such as the inability to achieve controllable hierarchical separation, the disadvantage of multi-resource recovery, high carbon emissions, and poor wastewater treatment effect.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A controllable, staged separation-electron flow-regulated wastewater treatment system, comprising: A multi-stage membrane separation module is used to controllably and hierarchically separate high-salt chemical wastewater into concentrated organic wastewater and inorganic wastewater. An inorganic salt recovery module is connected to a multi-stage membrane separation module. The inorganic salt recovery module uses electrolysis to convert inorganic salts in inorganic wastewater into acidic solutions, alkaline solutions, and salt crystals. The biological treatment module is connected to a multi-stage membrane separation module. The biological treatment module uses biological methods to treat concentrated organic wastewater and achieves biogasification and sulfur recovery of the concentrated organic wastewater through directional regulation of electron flow distribution. A biogas resource recovery module, which is connected to a biological treatment module, is used to recover energy from biogas cogeneration. A sludge treatment module is connected to a biological treatment module. The sludge treatment module is used to perform solid-liquid separation on the excess sludge produced by the biological treatment module to obtain sludge cake and reflux liquid, and the reflux liquid is returned to the biological treatment module.

[0006] As a further embodiment of the present invention: the multi-stage membrane separation module includes an equalization tank, an ultrafiltration module, a nanofiltration module, a nanofiltration permeate tank, a reverse osmosis module, and an ultrafiltration-nanofiltration concentrate tank. The outlet of the equalization tank is connected to the inlet of the ultrafiltration module, the permeate outlet of the ultrafiltration module is connected to the inlet of the nanofiltration module, the permeate outlet of the nanofiltration module is connected to the inlet of the nanofiltration permeate tank, the concentrate outlets of the ultrafiltration module and the nanofiltration module are connected to the inlet of the ultrafiltration-nanofiltration concentrate tank, the outlet of the nanofiltration permeate tank is connected to the inlet of the reverse osmosis module, the concentrate outlet of the reverse osmosis module is connected to an inorganic salt recovery module, the permeate outlet of the reverse osmosis module discharges recycled water, and the ultrafiltration-nanofiltration concentrate tank is connected to a biological treatment module. In use, the ultrafiltration, nanofiltration and reverse osmosis components controllably and hierarchically separate high-salt chemical wastewater into concentrated organic wastewater and inorganic wastewater. The concentrated organic wastewater is rich in sodium sulfate, and the inorganic wastewater is rich in sodium chloride.

[0007] As a further aspect of the present invention: the ultrafiltration component includes an ultrafiltration membrane, wherein the ultrafiltration membrane has a molecular weight cutoff range of 1000 Da-3000 Da; The nanofiltration assembly includes a nanofiltration membrane, wherein the nanofiltration membrane has a molecular weight cutoff range of 100 Da to 500 Da; The reverse osmosis component includes a reverse osmosis membrane, wherein the sodium chloride rejection rate of the reverse osmosis membrane is greater than or equal to 95%.

[0008] As a further aspect of the present invention: the inorganic salt recovery module includes a bipolar membrane electrodialysis component, a tubular heat exchanger, and a crystallization tower. The inlet of the bipolar membrane electrodialysis component is connected to the concentrate outlet of the reverse osmosis component, the outlet of the bipolar membrane electrodialysis component is connected to the feed inlet of the tubular heat exchanger, and the outlet of the tubular heat exchanger is connected to the crystallization tower. The bipolar membrane electrodialysis component decomposes the inorganic wastewater into acid and alkali solutions, and the crystallization tower is used to generate salt crystals.

[0009] As a further aspect of the present invention: the current density of the bipolar membrane electrodialysis module is 100 A / m 2 -500A / m 2 The bipolar membrane electrodialysis module generates acid and alkali solutions with a volume concentration range of 0.5M-2.0M.

[0010] As a further aspect of the present invention: the biological treatment module includes an anaerobic biogas production system and a biological sulfur recovery system. The anaerobic biogas production system includes a high-efficiency electrocatalytic reactor, an anaerobic reactor, an anoxic / aerobic tank, a sedimentation tank, and a sterilization tank. The inlet of the high-efficiency electrocatalytic reactor is connected to the outlet of the ultrafiltration-nanofiltration concentrate tank. The outlet of the high-efficiency electrocatalytic reactor is connected to the inlet of the anaerobic reactor. The outlet of the anaerobic reactor is connected to the inlet of the anoxic / aerobic tank. The residual sludge outlet of the anaerobic reactor is connected to the sludge treatment module. The top gas outlet of the anaerobic reactor is connected to the biogas resource utilization module. The outlet of the anoxic / aerobic tank is connected to the inlet of the first sedimentation tank. The residual sludge outlet of the anoxic / aerobic tank is connected to the sludge treatment module. The outlet of the first sedimentation tank is connected to the inlet of the sterilization tank. The bottom sludge outlet of the first sedimentation tank is connected to the anoxic / aerobic tank and the sludge treatment module. The outlet of the sterilization tank discharges recycled water. The biological sulfur recovery system includes a biological sulfur oxidation reactor, a sedimentation tank, and a tubular separator. The inlet of the biological sulfur oxidation reactor is connected to the biogas resource utilization module, and the outlet of the biological sulfur oxidation reactor is connected to the inlet of the second sedimentation tank. The remaining sludge in the second sedimentation tank is connected to the biological sulfur oxidation reactor and the sludge treatment module. The outlet of the second sedimentation tank is connected to the inlet of the tubular separator. The tubular separator separates and collects elemental sulfur in solid phase form, and the outlet of the tubular separator is connected to the inlet of the sterilization and disinfection tank.

[0011] As a further aspect of the present invention: the high-efficiency electrocatalytic reactor is connected to an external power source and drives the electrode reaction through the applied voltage of the external power source. The electrocatalytic electron flow generated by the high-efficiency electrocatalytic reactor directly participates in the hydrolysis and acidification process of organic matter. The high-efficiency electrocatalytic reactor includes an anode and a cathode, and the distance between the anode and cathode electrodes is 5mm-30mm. The anaerobic reactor has a reflux ratio of 0.5-5.0, operates at 30-40℃, has a pH of 6.8-7.5, and has an anaerobic retention time of 12-24 hours. The anoxic / aerobic tank's anoxic section controls the dissolved oxygen concentration at 0.2 mg / L-0.5 mg / L by limiting the reflux ratio, while the aerobic section uses a 1m... 3 / (m 3 ·h)-3m 3 / (m 3 The aeration rate of ·h) will maintain the dissolved oxygen concentration at 2mg / L-4mg / L; The O / S ratio of the bio-sulfur oxidation reactor is controlled at 0.5-1.5, and the dissolved oxygen concentration is maintained at 0.1 mg / L-0.5 mg / L.

[0012] As a further aspect of the present invention: the biogas resource recovery module includes a desulfurization tower, a drying tower, a gas storage tank, and a cogeneration unit. The inlet of the desulfurization tower is connected to the top outlet of the anaerobic reactor, the outlet of the desulfurization tower is connected to the drying tower, the washing liquid outlet of the desulfurization tower is connected to the liquid inlet of the biological sulfur oxidation reactor, the gas outlet pipe of the drying tower is connected to the inlet of the gas storage tank, and the gas outlet of the gas storage tank is connected to the cogeneration unit. The cogeneration unit recovers energy from the biogas.

[0013] As a further aspect of the present invention: a pressure regulator is provided between the gas storage tank and the cogeneration unit, and the pressure regulator is used for gas pressure regulation; The desulfurization tower introduces alkaline solution generated by the bipolar membrane electrodialysis unit, and the liquid-to-gas ratio of the gas and alkaline solution introduced into the desulfurization tower is 5 L / m³. 3 -15L / m 3 .

[0014] As a further aspect of the present invention: the sludge treatment module includes a sludge thickening tank and a plate and frame filter press. The inlet of the sludge thickening tank is connected to the bottom sludge outlet of the anaerobic reactor, the anoxic / aerobic tank, and the sedimentation tank. The outlet of the sludge thickening tank is connected to the second inlet of the anoxic / aerobic tank. The sludge discharge outlet of the sludge thickening tank is connected to the inlet of the plate and frame filter press. The outlet of the plate and frame filter press is connected to the second inlet of the anoxic / aerobic tank. Both the sludge thickening tank and the plate and frame filter press generate reflux liquid, which is returned to the anoxic / aerobic tank. The plate and frame filter press produces sludge cake.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses ultrafiltration, nanofiltration, and reverse osmosis components in a multi-stage membrane separation module to precisely separate organic matter and inorganic salts in high-salt chemical wastewater. The inorganic salt recovery module, consisting of a bipolar membrane electrodialysis component and a crystallization tower, forms a bipolar membrane electrodialysis-crystallization coupling system. This system simultaneously recovers acid, alkali, and salt resources during inorganic salt treatment. Organic matter undergoes a multi-module anaerobic biological treatment-sulfur speciation control process, achieving synergistic conversion of carbon, nitrogen, and sulfur to produce biogas and elemental sulfur. This effectively solves the problems of resource waste and secondary pollution in traditional treatment methods. It can recover multiple resources when dealing with various pollutants. The graded treatment of organic matter and inorganic salts in high-salt wastewater not only improves resource recovery efficiency but also significantly reduces energy consumption during the treatment process.

[0016] 2. This invention organically combines membrane separation, electrochemical conversion, and biological treatment technologies, and solves the separation and conversion challenges caused by the coexistence of multiple pollutants by directional control of electron flow among multiple modules. It constructs a closed-loop system of graded separation, material recovery, and energy reuse, realizing the efficient treatment and resource utilization of high-salt chemical wastewater. By optimizing the synergistic effect between modules and through the synergistic effect of electrochemical and biological treatment technologies, the problem of multiple pollutant coexistence is solved by directional control of electron flow. This not only enhances the recovery efficiency of acid, alkali, and salt resources, but also improves the biogasification of organic wastewater and the recovery of elemental sulfur, minimizing energy consumption and operating costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0018] In the diagram: 1. Equalization tank; 2. Ultrafiltration unit; 3. Nanofiltration unit; 4. Nanofiltration permeate tank; 5. Reverse osmosis unit; 6. Ultrafiltration-nanofiltration concentrate tank; 7. Bipolar membrane electrodialysis unit; 8. Tubular heat exchanger; 9. Crystallization tower; 10. High-efficiency electrocatalytic reactor; 11. Anaerobic reactor; 12. Anoxic / aerobic tank; 13. First sedimentation tank; 14. Sterilization tank; 15. Biological sulfur oxidation reactor; 16. Second sedimentation tank; 17. Tubular separator; 18. Sludge thickening tank; 19. Plate and frame filter press; 20. Desulfurization tower; 21. Drying tower; 22. Gas storage tank; 23. Pressure regulator; 24. Cogeneration unit. Detailed Implementation

[0019] 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.

[0020] Example 1: Please see Figure 1 This embodiment provides a controllable, staged separation-electrofluid-regulated wastewater treatment system, including a multi-stage membrane separation module, an inorganic salt recovery module, a biological treatment module, a biogas resource utilization module, and a sludge treatment module. A multi-stage membrane separation module is used to introduce high-salt chemical wastewater. The multi-stage membrane separation module is used to controllably and hierarchically separate the high-salt chemical wastewater into organic concentrated wastewater and inorganic wastewater. The multi-stage membrane separation module includes an equalization tank 1, an ultrafiltration module 2, a nanofiltration module 3, a nanofiltration permeate tank 4, a reverse osmosis module 5, and an ultrafiltration-nanofiltration concentrate tank 6. The outlet of the equalization tank 1 is connected to the inlet of the ultrafiltration module 2. The permeate outlet of the ultrafiltration module 2 is connected to the inlet of the nanofiltration module 3. The permeate outlet of the nanofiltration module 3 is connected to the inlet of the nanofiltration permeate tank 4. The concentrate outlets of the ultrafiltration module 2 and the nanofiltration module 3 are connected to the inlet of the ultrafiltration-nanofiltration concentrate tank 6. The outlet of the nanofiltration permeate tank 4 is connected to the inlet of the reverse osmosis module 5. The concentrate outlet of the reverse osmosis module 5 is connected to the inorganic salt recovery module. The permeate outlet of the reverse osmosis module 5 discharges the recovered water. The ultrafiltration-nanofiltration concentrate tank 6 is connected to the biological treatment module. As a further aspect of the present invention: the ultrafiltration component 2 includes an ultrafiltration membrane with a molecular weight cutoff of 1000 Da to 3000 Da; the nanofiltration component 3 includes a nanofiltration membrane with a molecular weight cutoff of 100 Da to 500 Da; and the reverse osmosis component 5 includes a reverse osmosis membrane with a sodium chloride rejection rate of ≥95%.

[0021] When in use, the ultrafiltration module 2, nanofiltration module 3 and reverse osmosis module 5 controllably and hierarchically separate the high-salt chemical wastewater into organic concentrated wastewater and inorganic wastewater. The organic concentrated wastewater is organic wastewater rich in sodium sulfate, and the inorganic wastewater is inorganic wastewater rich in sodium chloride. In this embodiment, the ultrafiltration component 2 includes an ultrafiltration membrane, and the molecular weight cutoff of the ultrafiltration membrane is in the range of 1000 Da-3000 Da. Nanofiltration module 3 includes a nanofiltration membrane with a molecular weight cutoff range of 100 Da to 500 Da; The reverse osmosis module 5 includes a reverse osmosis membrane with a sodium chloride rejection rate of ≥95%.

[0022] Specifically, the ultrafiltration component 2 can effectively remove large molecular organic matter and suspended solids in wastewater, providing pretreatment guarantee for subsequent treatment stages. The nanofiltration component 3 further retains smaller molecular weight organic matter and some inorganic salts, achieving selective separation of specific pollutants in wastewater. The reverse osmosis component 5, driven by high pressure, efficiently retains dissolved salts, ensuring that the effluent water quality meets strict discharge or reuse standards. Hollow fiber or tubular ultrafiltration membranes are used for preliminary filtration of wastewater. Their large membrane area and high porosity effectively improve treatment efficiency. This type of membrane structure has strong anti-fouling ability during operation and can adapt to the treatment needs under different water quality conditions. Furthermore, the design of hollow fiber or tubular membranes facilitates cleaning and maintenance, reduces system operating costs, and ensures long-term stable performance. Spiral wound nanofiltration membranes are used for finer filtration of wastewater. Their special membrane structure can effectively separate smaller molecular weight organic matter and some inorganic salts in wastewater. The spiral wound membrane design ensures high filtration efficiency while also having good pressure resistance, enabling stable operation under various operating conditions. The compact structure of this type of membrane reduces the equipment footprint and facilitates integration into the overall wastewater treatment system, further improving the system's space utilization and operational flexibility.

[0023] The inorganic salt recovery module is connected to a multi-stage membrane separation module. The inorganic salt recovery module uses electrolysis to convert inorganic salts in the inorganic wastewater into acidic solutions, alkaline solutions, and salt crystals. The inorganic salt recovery module includes a bipolar membrane electrodialysis component 7, a tubular heat exchanger 8, and a crystallization tower 9. The inlet of the bipolar membrane electrodialysis component 7 is connected to the concentrate outlet of the reverse osmosis component 5, the outlet of the reverse osmosis component 5 is connected to the inlet of the tubular heat exchanger 8, and the outlet of the tubular heat exchanger 8 is connected to the crystallization tower 9. The bipolar membrane electrodialysis component 7 is used for electrolysis to generate acidic and alkaline solutions, and the crystallization tower 9 is used to generate salt crystals. In this embodiment, the current density of the bipolar membrane electrodialysis module 7 is 100 A / m. 2 -500A / m 2 The bipolar membrane electrodialysis module 7 electrolyzes acid and alkali solutions with a volume concentration range of 0.5M-2.0M.

[0024] Specifically, the current density of the bipolar membrane electrodialysis module 7 is 100 A / m 2 -500A / m 2The system can be flexibly adjusted according to actual treatment needs to ensure ideal acid and alkali solution generation under different water quality conditions. This component exhibits excellent stability and controllability during operation, effectively handling complex components in wastewater. Its high-efficiency electrolysis significantly increases the generation rate of acid and alkali solutions. The bipolar membrane electrodialysis component 7 generates acid and alkali solutions with a volume concentration range of 0.5M-2.0M, precisely controlled to meet the needs of different wastewater treatment processes. This flexibility allows the system to maintain high-efficiency treatment capacity even when dealing with various wastewater types. Furthermore, the generated acid and alkali solutions are of high purity and can be directly used in subsequent neutralization reactions or other chemical treatment stages, reducing the need for external chemicals, further lowering operating costs, and improving the system's environmental performance. The biological treatment module, connected to the multi-stage membrane separation module, uses biological methods to treat concentrated organic wastewater. Through directional regulation of electron flow distribution, it achieves biogasification and sulfur recovery from the concentrated organic wastewater. The biological treatment module includes an anaerobic biogas production system and a biological sulfur recovery system. The anaerobic biogas production system comprises a high-efficiency electrocatalytic reactor 10, an anaerobic reactor 11, an anoxic / aerobic tank 12, a sedimentation tank, and a sterilization tank 14. The inlet of the high-efficiency electrocatalytic reactor 10 is connected to the outlet of the ultrafiltration-nanofiltration concentrate tank 6, and the outlet pipe of the high-efficiency electrocatalytic reactor 10 is connected to the inlet of the anaerobic reactor 11. The outlet of the anaerobic reactor 11 is connected to the inlet of the anoxic / aerobic tank 12, and the excess sludge outlet of the anaerobic reactor 11 is connected to the wastewater treatment system. The sludge treatment module has the following connections: the top gas outlet of the anaerobic reactor 11 is connected to the biogas resource utilization module; the outlet of the anoxic / aerobic tank 12 is connected to the inlet of the first sedimentation tank 13; the excess sludge outlet of the anoxic / aerobic tank 12 is connected to the sludge treatment module; the outlet of the first sedimentation tank 13 is connected to the inlet of the sterilization and disinfection tank 14; the bottom sludge outlet of the first sedimentation tank 13 is connected to both the anoxic / aerobic tank 12 and the sludge treatment module; and the outlet of the sterilization and disinfection tank 14 discharges recycled water. The aerobic section of the anoxic / aerobic tank 12 is 1-3m long. 3 / (m 3 The aeration rate of h) maintains the dissolved oxygen concentration at 2 mg / L-4 mg / L. In the anoxic zone, the dissolved oxygen concentration is controlled at 0.2 mg / L-0.5 mg / L by limiting the reflux ratio. This is used to achieve effective degradation of organic matter and efficient removal of nitrogen and phosphorus. By precisely controlling the aeration rate and reflux ratio, the system can form a suitable microbial community structure at different treatment stages, thereby optimizing the pollutant conversion efficiency. The biological sulfur recovery system includes a biological sulfur oxidation reactor 15, a sedimentation tank, and a tubular separator 17. The inlet of the biological sulfur oxidation reactor 15 is connected to the biogas resource utilization module, and the outlet of the biological sulfur oxidation reactor 15 is connected to the inlet of the second sedimentation tank 16. The remaining sludge in the second sedimentation tank 16 is connected to the biological sulfur oxidation reactor 15 and the sludge treatment module. The outlet of the second sedimentation tank 16 is connected to the inlet of the tubular separator 17. The tubular separator 17 separates and collects elemental sulfur in solid form. The outlet of the tubular separator 17 is connected to the inlet of the sterilization and disinfection tank 14. The O / S (oxidation-reduction potential) of the biological sulfur oxidation reactor 15 is controlled at 0.5mV-1.5mV to regulate the activity of sulfur-oxidizing bacteria, and the dissolved oxygen concentration is maintained at 0.1mg / L-0.5mg / L. In this embodiment, the high-efficiency electrocatalytic reactor 10 is connected to an external power source and drives the electrode reaction through the applied voltage of the external power source. The electrocatalytic electron flow generated by the high-efficiency electrocatalytic reactor 10 directly participates in the hydrolysis and acidification process of organic matter. The high-efficiency electrocatalytic reactor 10 includes an anode and a cathode, and the distance between the anode and cathode electrodes is 5mm-30mm. The high-efficiency electrocatalytic reactor 10 drives the electrode reaction through an applied voltage. The anode adopts an inert electrode material with a high oxygen evolution overpotential, and the cathode adopts an electrode material with high catalytic activity. The distance between the anode and cathode is controlled between 5mm-30mm and is adjustable. Specifically, the anode material can be titanium-based lead dioxide (Ti / PbO2) or boron-doped diamond (BDD) electrodes. These materials not only possess excellent chemical stability and conductivity but also effectively suppress oxygen evolution side reactions, thereby improving current efficiency. The cathode material can utilize supported noble metal catalysts (such as Pt / C, Pd / C) or transition metal compounds (such as Ni-Co alloys, Fe3O4 nanoparticle-modified electrodes) to enhance catalytic activity against organic hydrolysis and acidification reactions, accelerating the decomposition and transformation of pollutants. The electrode spacing can be adjusted using sliding rails and fixing clips inside the reactor. Operators can flexibly adjust the spacing based on the concentration of the treated water, the composition of pollutants, and the required reaction efficiency. When treating high-concentration organic wastewater, appropriately reducing the electrode spacing (e.g., 5mm-15mm) can lower solution resistance and improve mass transfer efficiency. For low-concentration wastewater or wastewater containing easily scale-forming substances, the spacing can be appropriately increased (e.g., 15mm-30mm) to reduce fouling on the electrode surface and extend the operating cycle.

[0025] In this embodiment, the anaerobic reactor 11 has a reflux ratio of 0.5-5.0, operates at 30-40℃, has a pH of 6.8-7.5, and has an anaerobic retention time of 12h-24h. Specifically, the reflux ratio can be controlled by a variable frequency reflux pump installed on the reactor effluent pipeline. Operators can dynamically adjust it based on parameters such as the operating load of the anaerobic system, the concentration of volatile fatty acids (VFA), and the methane yield. When the VFA concentration in the reactor is too high (e.g., exceeding 1500 mg / L) or there is a risk of acidification, appropriately increasing the reflux ratio (e.g., 3.0-5.0) can return part of the treated effluent to the reactor inlet, diluting the organic matter concentration in the influent, buffering pH fluctuations, and simultaneously increasing the hydraulic stirring intensity in the reactor to promote sufficient contact between the sludge and the substrate. When the system is operating stably and the organic matter removal effect is good, the reflux ratio can be reduced to 0.5-2.0 to reduce energy consumption and avoid excessive stirring that could damage the structure of the anaerobic granular sludge. Maintaining the operating temperature relies on the jacketed heating system surrounding the reactor or the built-in coil heat exchanger. The temperature of the heating medium (e.g., hot water or thermal oil) is precisely controlled by an intelligent temperature controller to stabilize the reactor temperature within a medium temperature range of 30-40℃. This temperature range provides the optimal growth environment for functional microorganisms such as methanogens. When the temperature is below 30℃, microbial activity decreases significantly, leading to a slower rate of organic matter degradation. Temperatures above 40℃ may inhibit the metabolic activity of some mesophilic bacteria and even cause sludge floating. pH control typically employs a combination of online pH monitoring and automatic dosing. When the pH in the reactor is detected to be below 6.8, alkaline agents such as sodium carbonate or sodium bicarbonate are automatically added to neutralize excess organic acids. If the pH is above 7.5, a small amount of hydrochloric acid or phosphoric acid can be added to adjust the pH, ensuring the reaction environment remains within the optimal acid-base range of 6.8-7.5, providing stable chemical conditions for microbial metabolic activity. The anaerobic retention time is mainly controlled by adjusting the influent flow rate. When treating high-concentration organic wastewater, the hydraulic retention time can be appropriately extended to 18-24 hours to ensure sufficient time for microbial decomposition and transformation of organic matter. For medium- and low-concentration wastewater, the hydraulic retention time can be shortened to 12-18 hours to improve the reactor's treatment load and operating efficiency. Meanwhile, the effluent quality needs to be monitored regularly, and the hydraulic retention time should be optimized and adjusted based on parameters such as sludge concentration, volatile suspended solids (VSS) to suspended solids (SS) ratio, to ensure long-term stable operation of the system.

[0026] In this embodiment, the anoxic section of the anoxic / aerobic tank 12 controls the dissolved oxygen concentration at 0.2 mg / L-0.5 mg / L by limiting the reflux ratio, while the aerobic section maintains the dissolved oxygen concentration at 2 mg / L-4 mg / L by using an aeration rate of 1 m³ / (m³·h)-3 m³ / (m³·h).

[0027] Specifically, limiting the recirculation ratio in the anoxic section can be achieved by adjusting the frequency of the internal recirculation pump or the valve opening. Generally, the recirculation ratio is controlled between 100% and 300% to reduce the influx of high-dissolved-oxygen mixture from the aerobic section, thus avoiding disruption of the anoxic environment. When the influent carbon source is sufficient, the recirculation ratio can be appropriately reduced to 100%-200% to ensure that denitrifying bacteria can fully utilize the carbon source in the water for denitrification. If the influent carbon source is insufficient, the recirculation ratio can be increased to 200%-300% to supplement some carbon source through the recirculated liquid, maintaining the continuous denitrification process. The aeration rate control in the aerobic section depends on the type of aeration equipment. For example, when using a microporous aerator, the aeration rate can be stabilized within the set range by adjusting the blower's outlet pressure and airflow. In actual operation, the aeration rate needs to be adjusted in real time based on the online dissolved oxygen monitoring data of the aerobic section. When the dissolved oxygen concentration is below 2 mg / L, the aeration rate should be increased, such as by increasing the blower speed or turning on the standby aeration unit. When the dissolved oxygen concentration is above 4 mg / L, the aeration rate should be reduced to prevent excessive aeration from increasing energy consumption and sludge aging. Meanwhile, the stirring device installed in the aerobic section ensures uniform mixing of the liquid, guaranteeing even distribution of dissolved oxygen within the tank and avoiding localized areas of hypoxia or hyperxia. This ensures the activity of aerobic microorganisms and their efficient degradation of organic matter.

[0028] The biogas resource recovery module is connected to the biological treatment module and is used to recover energy from biogas through cogeneration. The biogas resource recovery module includes a desulfurization tower 20, a drying tower 21, a gas storage tank 22, and a cogeneration unit 24. The inlet of the desulfurization tower 20 is connected to the top outlet of the anaerobic reactor 11, the outlet of the desulfurization tower 20 is connected to the drying tower 21, the washing liquid outlet of the desulfurization tower 20 is connected to the liquid inlet of the biological sulfur oxidation reactor 15, the gas outlet pipe of the drying tower 21 is connected to the inlet of the gas storage tank 22, and the gas outlet of the gas storage tank 22 is connected to the cogeneration unit 24, which recovers energy from the biogas.

[0029] Specifically, the desulfurization tower 20 is filled with a high-efficiency desulfurizing agent and employs a wet desulfurization process. Alkaline scrubbing liquid fully contacts and chemically reacts with hydrogen sulfide in the biogas, absorbing and removing the hydrogen sulfide to reduce the sulfur content in the biogas and prevent corrosion of subsequent equipment. After absorbing hydrogen sulfide, the scrubbing liquid is discharged from the scrubbing liquid outlet and enters the biological sulfur oxidation reactor 15. Under the action of specific microorganisms in the reactor, the sulfides in the scrubbing liquid are further oxidized and decomposed, achieving the regeneration of the scrubbing liquid and the recovery of sulfur resources. The drying tower 21 is mainly used to remove moisture from the biogas. It can be equipped with an adsorbent layer or cooling coils. When biogas enters the drying tower 21 from the desulfurization tower 20, it is subjected to contact with the adsorbent or cooling treatment, causing the water vapor to be adsorbed or condensed and separated, thereby reducing the humidity of the biogas and preventing the subsequent gas storage tank 22 and cogeneration unit 24 from being affected by moisture, thus preventing operational efficiency issues or equipment damage. The gas holder 22 serves as a biogas storage facility, balancing biogas production and consumption. When the biogas produced by the anaerobic reactor 11 exceeds the immediate consumption of the cogeneration unit 24, the excess biogas can be stored in the gas holder 22. When biogas production is insufficient, the gas holder 22 releases the stored biogas to ensure the stable operation of the cogeneration unit 24. The cogeneration unit 24 includes a gas-fired internal combustion engine or gas turbine, a generator, and a waste heat boiler. After entering the cogeneration unit 24 through the gas holder 22, the biogas first mixes and burns with air in the combustion chamber. The resulting high-temperature, high-pressure gas drives the internal combustion engine or gas turbine, which in turn drives the generator to generate electricity, thus recovering electrical energy. The high-temperature flue gas generated during combustion is used for heat recovery through the waste heat boiler. The generated steam or hot water can be used for heating in the plant area, process heating, etc., realizing the cascade utilization of biogas energy and improving energy efficiency.

[0030] In this embodiment, a pressure regulator 23 is provided between the gas storage tank 22 and the cogeneration unit 24, and the pressure regulator 23 is used for gas pressure regulation. The desulfurization tower 20 introduces the alkaline solution generated by the bipolar membrane electrodialysis module 7. The liquid-to-gas ratio of the gas and alkaline solution introduced into the desulfurization tower 20 is 5 L / m³. 3 -15L / m 3 .

[0031] Specifically, the desulfurization tower 20 ensures sufficient contact and reaction between the alkaline solution and the introduced gas by precisely controlling the liquid-to-gas ratio, thereby effectively removing sulfides from the gas. The pressure regulator 23 not only ensures the safety of gas transportation, but also improves the efficiency of subsequent processes through stable pressure output. While achieving efficient desulfurization, it also significantly reduces resource consumption and the risk of secondary pollution, providing a more environmentally friendly and economical solution for wastewater treatment.

[0032] The sludge treatment module is connected to the biological treatment module. The sludge treatment module is used to separate the solid and liquid of the excess sludge produced by the biological treatment module and obtain sludge cake and return liquid. The return liquid is returned to the biological treatment module. The sludge treatment module includes a sludge thickening tank 18 and a plate and frame filter press 19. The inlet of the sludge thickening tank 18 is connected to the bottom sludge outlet of the anaerobic reactor 11, the anoxic / aerobic tank 12, and the sedimentation tank. The outlet of the sludge thickening tank 18 is connected to the second inlet of the anoxic / aerobic tank 12. The sludge discharge outlet of the sludge thickening tank 18 is connected to the inlet of the plate and frame filter press 19. The outlet of the plate and frame filter press 19 is connected to the second inlet of the anoxic / aerobic tank 12. Both the sludge thickening tank 18 and the plate and frame filter press 19 generate reflux liquid, which is returned to the anoxic / aerobic tank 12. The plate and frame filter press 19 produces sludge cake.

[0033] In summary, this invention achieves precise fractional separation of organic matter and inorganic salts in high-salt chemical wastewater through a multi-stage membrane separation module; the inorganic salt recovery module employs a bipolar membrane electrodialysis-crystallization coupling system to simultaneously recover acid, alkali, and salt resources; and the concentrated organic wastewater undergoes anaerobic biological treatment and sulfur speciation regulation through a biological treatment module to achieve synergistic conversion of carbon, nitrogen, and sulfur, as well as energy recovery. A closed-loop system of fractional separation, material recovery, and energy reuse is constructed among the modules. Compared with existing technologies, this invention effectively solves the problems of low separation efficiency and significant resource waste caused by the coexistence of multiple pollutants in high-salt wastewater treatment, significantly improves resource recovery efficiency, and reduces system energy consumption and operating costs.

[0034] Example 2: The present invention also provides a controllable graded separation-electron flow regulation wastewater treatment, which includes the following specific steps; S1: The various streams of high-salt wastewater generated during the chemical process enter the equalization tank 1. A stirring device is installed in the equalization tank 1. A propeller / paddle mixer is used to stir and homogenize the wastewater in the equalization tank 1. The speed is between 100-300 rpm to alleviate the impact of uneven wastewater on the subsequent sewage treatment system. After the wastewater is fully stirred and homogenized, homogenized wastewater is obtained. S2: The homogeneous high-salt wastewater obtained in step S1 is pumped into ultrafiltration module 2 to separate the large molecular organic matter in the high-salt chemical wastewater. The product water of ultrafiltration module 2 is pumped into nanofiltration module 3 to further separate the small molecular organic matter (molecular weight between 200-1000 Da) in the high-salt chemical wastewater. At the same time, sodium sulfate and sodium chloride in the wastewater are separated, resulting in organic wastewater containing sodium sulfate and sodium chloride wastewater. The product water of nanofiltration module 3 (i.e. sodium chloride wastewater) enters nanofiltration product water tank 4. The concentrated water produced by ultrafiltration module 2 and nanofiltration module 3 enters ultrafiltration-nanofiltration concentrated water tank 6 through pipeline. S3: The sodium chloride wastewater obtained in step S2 is pumped from nanofiltration permeate tank 4 into reverse osmosis module 5 for further concentration. The concentrated brine produced by reverse osmosis module 5 enters bipolar membrane electrodialysis module 7 to convert sodium chloride into hydrochloric acid and sodium hydroxide. The sodium chloride wastewater flowing out of bipolar membrane electrodialysis module 7 enters tubular heat exchanger 8 through pipeline, is preheated to 60-80 ℃, and then enters crystallization tower 9 through pipeline. Cooling or further evaporation is used to promote the precipitation of sodium chloride crystals from the supersaturated solution, producing sodium chloride crystals. The stirring speed in the crystallization tower is controlled between 50-150 rpm to prevent the deposition of sodium chloride crystal particles, while maintaining uniform solution mixing to promote the crystallization process. S4: The organic wastewater containing sodium sulfate obtained in step S2 is pumped from the ultrafiltration-nanofiltration concentrate tank 6 into the high-efficiency electrocatalytic system 10 to degrade the toxic substances in the wastewater and reduce its toxicity. The resulting low-toxicity organic wastewater is then pumped into the anaerobic reactor 11, which contains anaerobic granular sludge. In the anaerobic environment, the sludge decomposes the organic matter in the wastewater into methane and other small-molecule organic matter, while reducing sulfate to hydrogen sulfide. Through a three-phase separator, water, gas, and solid separation is achieved at the outlet. Methane, hydrogen sulfide, and other gases enter the gas resource utilization module IV. The effluent from the anaerobic reactor 11 enters the anoxic / aerobic tank 12 through a pipeline. The tank contains activated sludge containing facultative anaerobic / aerobic bacteria. An aeration device is installed in the aerobic tank, and a blower is used to blow air into the aerobic tank through the aeration device. The organic matter in the wastewater is further decomposed into water and harmless substances such as carbon dioxide through biological action. S5: The aerobic tank effluent produced in step S4 enters the first sedimentation tank 13 through a pipe. The suspended solid particles in the water settle down by gravity, thereby achieving solid-liquid separation. The effluent from the first sedimentation tank 13 flows into the sterilization and disinfection tank 14 through a pipe. The pathogenic microorganisms in the water are killed by physical and chemical methods, further reducing the concentration of microorganisms in the water and improving the water quality of the recycled water. S6: In step S4, the gas generated by the anaerobic reactor 11 is collected by the gas collection system at the top of the reactor and transported to the gas resource utilization module IV through a pipeline. It then enters the desulfurization tower 20 through the air inlet. The biogas entering the desulfurization tower 20 is washed by the scrubbing liquid sprayed by the spray system, thereby removing the sulfides in the biogas. The resulting scrubbing liquid flows into the biological sulfur oxidation reactor 15 through a pipeline. The reactor contains sulfur-oxidizing bacteria and is equipped with an aeration device to blow air into the reactor. By controlling the micro-oxygen environment and bacterial activity, sulfides can be converted into elemental sulfur. The effluent from the biological sulfur oxidation reactor 15 enters the second sedimentation tank 16 through a pipeline. The sludge in the water settles down by gravity and flows back to the biological sulfur oxidation reactor 15. The effluent from the second sedimentation tank 16 enters the tubular separator 17 through a pipeline. The elemental sulfur in the water is separated by centrifugation. The resulting clear liquid flows to the sterilization and disinfection tank 14 for further treatment.

[0035] S7: In step S6, the desulfurized gas is transported to the drying tower 21 through the pipeline from the top of the desulfurization tower 20. As the biogas flows, the moisture is gradually adsorbed into the drying medium. The dried biogas is discharged through the exhaust port at the top of the tower and enters the gas storage tank 22 through the pipeline to balance the difference between gas production and demand. S8: The purified biogas in step S7 is introduced into the combustion system of the cogeneration unit 24 through the pressure regulator 23. The biogas is burned in the burner as fuel, and the released heat energy drives the generator to generate electricity and at the same time generates heat energy. The generated heat energy can be used to preheat the sodium chloride wastewater flowing out of the bipolar membrane electrodialysis component 7 through the tubular heat exchanger 8, and can also be supplied to the anaerobic reactor 11 in the biological treatment system through the heat exchange system. The electrical energy can be supplied to places that need electricity. S9: The residual sludge generated in step S4 from the anaerobic reactor 11 and the anoxic / aerobic tank 12, as well as the first sedimentation tank 13 in step S5, enters the sludge thickening tank 18 in the sludge treatment module V through pipelines. Some of the residual sludge generated in the sedimentation tank is returned to the anaerobic reactor 11 through pipelines, while most of the residual sludge is further concentrated in the sludge thickening tank 18 by gravity settling. The concentrated sludge is then pumped to the plate and frame filter press 19 by a sludge pump. The filter press consists of multiple filter plates and filter cloth. Under high pressure, the sludge is squeezed through the filter cloth to produce filtrate. The filtrate and the concentrated liquid generated in the sludge thickening tank 18 are returned to the anoxic / aerobic tank 12 for treatment. The remaining sludge is collected to form a sludge cake.

[0036] The above description is only a preferred embodiment 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 controllable, graded separation-electron flow-regulated wastewater treatment system, characterized in that, include: A multi-stage membrane separation module is used to controllably and hierarchically separate high-salt chemical wastewater into concentrated organic wastewater and inorganic wastewater. An inorganic salt recovery module is connected to a multi-stage membrane separation module. The inorganic salt recovery module uses electrolysis to convert inorganic salts in inorganic wastewater into acidic solutions, alkaline solutions, and salt crystals. The biological treatment module is connected to a multi-stage membrane separation module. The biological treatment module uses biological methods to treat concentrated organic wastewater and achieves biogasification and sulfur recovery of the concentrated organic wastewater through directional regulation of electron flow distribution. A biogas resource recovery module, which is connected to a biological treatment module, is used to recover energy from biogas cogeneration. A sludge treatment module is connected to a biological treatment module. The sludge treatment module is used to perform solid-liquid separation on the excess sludge produced by the biological treatment module to obtain sludge cake and reflux liquid, and the reflux liquid is returned to the biological treatment module.

2. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 1, characterized in that, The multi-stage membrane separation module includes an equalization tank, an ultrafiltration module, a nanofiltration module, a nanofiltration permeate tank, a reverse osmosis module, and an ultrafiltration-nanofiltration concentrate tank. The outlet of the equalization tank is connected to the inlet of the ultrafiltration module, the permeate outlet of the ultrafiltration module is connected to the inlet of the nanofiltration module, the permeate outlet of the nanofiltration module is connected to the inlet of the nanofiltration permeate tank, the concentrate outlets of the ultrafiltration and nanofiltration modules are connected to the inlet of the ultrafiltration-nanofiltration concentrate tank, the outlet of the nanofiltration permeate tank is connected to the inlet of the reverse osmosis module, the concentrate outlet of the reverse osmosis module is connected to an inorganic salt recovery module, the permeate outlet of the reverse osmosis module discharges recycled water, and the ultrafiltration-nanofiltration concentrate tank is connected to a biological treatment module. In use, the ultrafiltration, nanofiltration and reverse osmosis components controllably and hierarchically separate high-salt chemical wastewater into concentrated organic wastewater and inorganic wastewater. The concentrated organic wastewater is rich in sodium sulfate, and the inorganic wastewater is rich in sodium chloride.

3. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 2, characterized in that, The ultrafiltration assembly includes an ultrafiltration membrane, the ultrafiltration membrane having a molecular weight cutoff range of 1000 Da-3000 Da; The nanofiltration assembly includes a nanofiltration membrane, wherein the nanofiltration membrane has a molecular weight cutoff range of 100 Da to 500 Da; The reverse osmosis component includes a reverse osmosis membrane, wherein the sodium chloride rejection rate of the reverse osmosis membrane is greater than or equal to 95%.

4. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 1, characterized in that, The inorganic salt recovery module includes a bipolar membrane electrodialysis unit, a tubular heat exchanger, and a crystallization tower. The inlet of the bipolar membrane electrodialysis unit is connected to the concentrate outlet of the reverse osmosis unit, the outlet of the bipolar membrane electrodialysis unit is connected to the feed inlet of the tubular heat exchanger, and the outlet of the tubular heat exchanger is connected to the crystallization tower. The bipolar membrane electrodialysis unit decomposes the inorganic wastewater into acid and alkali solutions, and the crystallization tower is used to generate salt crystals.

5. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 4, characterized in that, The current density of the bipolar membrane electrodialysis module is 100 A / m 2 -500A / m 2 The bipolar membrane electrodialysis module generates acid and alkali solutions with a volume concentration range of 0.5M-2.0M.

6. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 1, characterized in that, The biological treatment module includes an anaerobic biogas production system and a biological sulfur recovery system. The anaerobic biogas production system comprises a high-efficiency electrocatalytic reactor, an anaerobic reactor, an anoxic / aerobic tank, a sedimentation tank, and a sterilization tank. The inlet of the high-efficiency electrocatalytic reactor is connected to the outlet of the ultrafiltration-nanofiltration concentrate tank. The outlet of the high-efficiency electrocatalytic reactor is connected to the inlet of the anaerobic reactor. The outlet of the anaerobic reactor is connected to the inlet of the anoxic / aerobic tank. The residual sludge outlet of the anaerobic reactor is connected to the sludge treatment module. The top gas outlet of the anaerobic reactor is connected to the biogas resource utilization module. The outlet of the anoxic / aerobic tank is connected to the inlet of the first sedimentation tank. The residual sludge outlet of the anoxic / aerobic tank is connected to the sludge treatment module. The outlet of the first sedimentation tank is connected to the inlet of the sterilization tank. The bottom sludge outlet of the first sedimentation tank is connected to both the anoxic / aerobic tank and the sludge treatment module. The outlet of the sterilization tank discharges recycled water. The biological sulfur recovery system includes a biological sulfur oxidation reactor, a sedimentation tank, and a tubular separator. The inlet of the biological sulfur oxidation reactor is connected to the biogas resource utilization module, and the outlet of the biological sulfur oxidation reactor is connected to the inlet of the second sedimentation tank. The remaining sludge in the second sedimentation tank is connected to the biological sulfur oxidation reactor and the sludge treatment module. The outlet of the second sedimentation tank is connected to the inlet of the tubular separator. The tubular separator separates and collects elemental sulfur in solid phase form, and the outlet of the tubular separator is connected to the inlet of the sterilization and disinfection tank.

7. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 6, characterized in that, The high-efficiency electrocatalytic reactor is connected to an external power source and drives the electrode reaction through the applied voltage of the external power source. The electrocatalytic electron flow generated by the high-efficiency electrocatalytic reactor directly participates in the hydrolysis and acidification process of organic matter. The high-efficiency electrocatalytic reactor includes an anode and a cathode, and the distance between the anode and cathode electrodes is 5mm-30mm. The anaerobic reactor has a reflux ratio of 0.5-5.0, operates at 30-40℃, has a pH of 6.8-7.5, and has an anaerobic retention time of 12-24 hours. The anoxic / aerobic tank's anoxic section controls the dissolved oxygen concentration at 0.2 mg / L-0.5 mg / L by limiting the reflux ratio, while the aerobic section uses a 1m... 3 / (m 3 ·h)-3m 3 / (m 3 The aeration rate of ·h) will maintain the dissolved oxygen concentration at 2mg / L-4mg / L; The O / S ratio of the bio-sulfur oxidation reactor is controlled at 0.5-1.5, and the dissolved oxygen concentration is maintained at 0.1 mg / L-0.5 mg / L.

8. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 1, characterized in that, The biogas resource utilization module includes a desulfurization tower, a drying tower, a gas storage tank, and a cogeneration unit. The inlet of the desulfurization tower is connected to the top outlet of the anaerobic reactor, the outlet of the desulfurization tower is connected to the drying tower, the washing liquid outlet of the desulfurization tower is connected to the liquid inlet of the biological sulfur oxidation reactor, the gas outlet pipe of the drying tower is connected to the inlet of the gas storage tank, and the gas outlet of the gas storage tank is connected to the cogeneration unit. The cogeneration unit recovers energy from the biogas.

9. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 8, characterized in that, A pressure regulator is installed between the gas storage tank and the cogeneration unit, and the pressure regulator is used for gas pressure regulation. The desulfurization tower introduces alkaline solution generated by the bipolar membrane electrodialysis unit, and the liquid-to-gas ratio of the gas and alkaline solution introduced into the desulfurization tower is 5 L / m³. 3 -15L / m 3 .

10. The controllable hierarchical separation-electron flow regulation wastewater treatment system according to claim 1, characterized in that, The sludge treatment module includes a sludge thickening tank and a plate and frame filter press. The inlet of the sludge thickening tank is connected to the bottom sludge outlet of the anaerobic reactor, the anoxic / aerobic tank, and the sedimentation tank. The outlet of the sludge thickening tank is connected to the second inlet of the anoxic / aerobic tank. The sludge discharge outlet of the sludge thickening tank is connected to the inlet of the plate and frame filter press. The outlet of the plate and frame filter press is connected to the second inlet of the anoxic / aerobic tank. Both the sludge thickening tank and the plate and frame filter press generate reflux liquid, which is returned to the anoxic / aerobic tank. The plate and frame filter press produces sludge cake.

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