Method and system device for resourceful treatment of high-salinity wastewater

Abstract

The invention provides a method and system device for resourceful treatment of high-salinity wastewater, and the method comprises the following steps: continuously providing 5wt%-20wt% of high-salinity wastewater to a salt chamber of a bipolar membrane electrodialysis device, carrying out bipolar membrane electrodialysis treatment, continuously discharging 2.5 wt%-13.4 wt% of light salt brine, then carrying out reverse osmosis treatment to obtain 8wt%-15wt% of strong brine, and carrying out water treatment on the strong brine to obtain the high-salinity wastewater. The obtained strong brine and the high-salinity wastewater are mixed in a parallel flow mode according to the volume flow ratio of (1.5-2.5): 1, and the mixed solution is continuously circulated into the salt chamber to be subjected to bipolar membrane electrodialysis treatment. The concentration fluctuation problem in the BMED reaction can be solved through the concentration-circulation closed-loop design, so that the power consumption, the cost, the concentration efficiency, the concentration stabilizing effect, the saline water utilization rate and the acid-base recovery effect are maximally balanced and considered, and the method has the characteristics of high purity, high concentration, high efficiency and high resource utilization.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment and relates to a method and system for the resource-based treatment of high-salinity wastewater. Background Technology

[0002] In the coal chemical industry, a large amount of complex wastewater with high salt and high organic matter concentration is generated during processes such as coal gasification, coal liquefaction, and coking. After evaporation and crystallization treatment, this wastewater produces mixed salt mother liquor rich in various anions and cations with large differences in solubility and complex crystallization behavior. However, the crystallization and salt separation efficiency of this by-product mother liquor is low and the purity is not high, making it difficult to use directly as industrial salt, resulting in a low degree of resource utilization.

[0003] In existing methods for treating mixed salt mother liquor, drying technology (physical dehydration) reduces volume by evaporating water using thermal energy. However, this method generally suffers from poor applicability, high failure rate, and high energy consumption. In contrast, bipolar membrane electrodialysis (BMED), as a green membrane separation technology that can achieve directional dissociation and transformation of salts, has attracted widespread attention. This technology utilizes a bipolar membrane to dissociate water molecules under the action of a DC electric field to generate H₂. + and OH - They combine with migrating ions to form corresponding acids or bases. By rationally designing the membrane stack structure and operating parameters, the selective separation and conversion of polyvalent and monovalent salts in the mother liquor can be achieved, thereby realizing acid-base regeneration and salt resource utilization.

[0004] However, in existing BMED technologies, the salt concentration in the salt chamber continuously decreases as ions migrate out, leading to a decrease in solution conductivity and a significant increase in overall system resistance. The traditional bipolar membrane electrodialysis (BMED) process described in patent CN111170421A suffers from a sharp increase in solution resistance and a surge in energy consumption in the later stages due to the continuous decay of salt chamber concentration during the reaction. Furthermore, patent CN116375267A, which only uses reverse osmosis (RO) as a pretreatment, cannot intervene in concentration fluctuations during the reaction. To maintain the required current density, the applied voltage must be increased accordingly, causing a sharp rise in energy consumption per unit of acid and alkali produced. Simultaneously, at low salt concentrations, the driving force for ion migration weakens, and membrane polarization intensifies, easily leading to reverse osmosis or membrane fouling, further deteriorating separation efficiency. More critically, excessively low salt chamber concentrations limit the H+ in the acid and alkali chambers. + With OH - The ineffective combination of these factors makes it difficult to increase the acid-base concentration produced, thus weakening the economic feasibility of the technology.

[0005] Therefore, new process strategies are still needed to overcome the limitations of existing technologies in terms of efficiency, energy consumption, and output. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method and system device for resource-based treatment of high-salt wastewater, so as to solve the bottleneck of concentration decay when bipolar membrane electrodialysis is used to treat high-concentration saline wastewater.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for resource-based treatment of high-salinity wastewater, the method comprising:

[0009] A bipolar membrane electrodialysis device is provided, comprising a salt chamber, an acid chamber, and an alkali chamber. High-salt wastewater with a mass concentration of 5wt% to 20wt% is continuously supplied to the salt chamber for bipolar membrane electrodialysis treatment, and a dilute brine with a mass concentration of 2.5wt% to 13.4wt% is continuously discharged. The dilute brine is then subjected to reverse osmosis treatment, concentrating it to a concentrated brine with a mass concentration of 8wt% to 15wt%. The concentrated brine and the high-salt wastewater are mixed in parallel at a volume flow ratio of (1.5 to 2.5):1 to form a mixed solution, which is continuously circulated back to the salt chamber for the bipolar membrane electrodialysis treatment.

[0010] In a bipolar membrane electrodialysis device, the bipolar membrane dissociates under an electric field to produce hydroxide and hydrogen ions. Under the electric field, anions migrate from the salt chamber to the acid chamber and combine with hydrogen ions to produce acid; cations migrate from the salt chamber to the alkali chamber and combine with hydroxide ions to produce alkali. The method described in this invention uses a high-salt-concentration (5wt%~20wt%) mixed salt mother liquor (i.e., high-salt wastewater) as the raw material to be treated. This is introduced into a bipolar membrane electrodialysis (BMED) system. When the salt chamber concentration reaches 2.5wt%~13.4wt%, the remaining solution (i.e., dilute brine) is drawn out and concentrated through reverse osmosis. The resulting concentrate is mixed with a new mixed salt mother liquor and returned to the salt chamber for continued electrodialysis to maintain a stable salt chamber concentration. This improves current efficiency and acid concentration while maximizing the utilization of salt and water resources, effectively supporting the continuous production of high-concentration, high-purity acids and alkalis by BMED. In this process, by controlling the concentration of reverse osmosis (RO) to a concentrated brine concentration of 8wt%~15wt% and the specific mixing ratio ((1.5~2.5):1) with high-salt wastewater, this concentration-recirculation closed-loop design can achieve a maximum balance and consideration in terms of power consumption, cost, concentration efficiency, concentration stability, brine utilization, and acid and alkali recovery, thereby ensuring the characteristics of high purity, high concentration, high efficiency, and high resource utilization.

[0011] For example, the concentration of the high-salinity wastewater described in this invention can be 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 18wt%, or 20wt%, etc.; 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, or 13.4wt%, etc. In the initial stage of the method described in this invention, the high-salinity wastewater can be first introduced into the BMED, and after passing through the RO to produce concentrated brine, the concentrated brine and the high-salinity wastewater are mixed to form a mixed solution, which is then introduced into the BMED in the form of a mixed solution. Specifically, this invention controls the initial feed concentration to 5wt%~20wt%, while controlling the outlet concentration to drop to 2.5wt%~13.4wt% before discharge and entering the RO for concentration. This is beneficial for maximizing the efficiency, energy consumption, and concentration stability of the BMED, and can avoid problems caused by concentration fluctuations.

[0012] For example, the concentrated brine obtained after the reverse osmosis treatment has a mass concentration of 8wt% to 15wt%, such as 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%, etc.; the volumetric flow rate ratio of the concentrated brine to the high-salinity wastewater is (1.5~2.5):1, such as 1.5:1, 1.8:1, 2:1, 2.2:1, 2.4:1, or 2.5:1, etc. Under a suitable mixing ratio of concentrated brine and high-salinity wastewater, the salt concentration of the mixed solution is stable, which not only meets the feed requirements of the BMED brine chamber but also helps maintain the stability of the brine concentration. Controlling the mass concentration of the concentrated brine within the range of 8wt% to 15wt% can maximize both concentration efficiency and energy consumption control, reducing energy consumption to 0.8 kWh. 3 ~1.0kWh / m 3 Concentrate. Simultaneously, by synergistically matching the target concentration of the brine treated by reverse osmosis with the mixing ratio of concentrated brine / high-salt wastewater, the mixture can not only improve ion migration efficiency to prevent reduced rate efficiency due to excessively low concentration, but also enhance membrane safety, helping to prevent crystallization or contamination problems caused by excessively high concentration, thereby extending membrane life and ensuring long-term stable operation of the process.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0014] This invention does not limit the source and type of high-salinity wastewater; it can be selected according to actual conditions to meet the requirements of this invention. For example, as a preferred technical solution of this invention, the high-salinity wastewater may optionally include by-product salt mother liquor from coal chemical wastewater.

[0015] As a preferred technical solution of the present invention, the method controls the chloride ion concentration in the mixed solution entering the salt chamber at 1.5 mol / L to 3.0 mol / L and the sulfate ion concentration at 1.2 mol / L to 2.5 mol / L through internal system circulation and process control, and maintains the molar ratio of chloride ions to sulfate ions at (0.75 to 1.33):1, without the need for an external chloride ion source or sulfate ion source. For example, the chloride ion concentration can be 1.5 mol / L, 1.8 mol / L, 2.0 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, or 3.0 mol / L, etc.; the sulfate ion concentration can be 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 2.0 mol / L, 2.2 mol / L, or 2.5 mol / L, etc.; the molar ratio of chloride ions to sulfate ions can be 0.75:1, 0.80:1, 0.85:1, 0.90:1, 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, or 1.33:1, etc.

[0016] The closed-loop system described in this invention can further stabilize the ionic composition of the mixed solution, the core of which lies in establishing an internal homeostatic equilibrium. This equilibrium originates from the coupling effect of the selective migration of ions by bipolar membrane electrodialysis (BMED) and reverse osmosis (RO)-mixed cycle, and its mechanism includes the following:

[0017] (1) Selective ion separation in the BMED salt chamber: Under the drive of a DC electric field, anions in the salt chamber migrate to the acid chamber. Due to chloride ions (Cl... - The migration rate of ions in an electric field and the apparent migration number of ions in ion exchange membranes (especially monovalent selective anion exchange membranes) are significantly higher than those of sulfate ions (SO4). 2- This results in SO4 being present in the brine discharged from the salt chamber. 2- Relative to Cl - SO4 is preferentially enriched in lightly salt water. 2- / Cl - The molar ratio is higher than that of the feed mixture.

[0018] (2) Feedback and amplification of circular logistics: The above-mentioned high SO4 content 2- / Cl -The dilute brine is concentrated to a mass concentration of 8wt%~15wt% (e.g., 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%) by the RO unit, thus preserving and amplifying its ion proportion characteristics. Subsequently, this concentrated brine is mixed with fresh high-salinity wastewater at a volumetric flow rate ratio of (1.5~2.5):1 (e.g., 1.5:1, 1.8:1, 2:1, 2.2:1, 2.4:1, or 2.5:1) to form a new batch of mixed solution entering the salt chamber.

[0019] (3) Establishment and regulation of dynamic equilibrium: During continuous operation, the system will spontaneously tend towards and eventually reach a dynamic steady state. Under this steady state, the amount of Cl that migrates from the salt chamber and is converted into the product via BMED per unit time is [not specified]. - With SO4 2- The ratio of the amounts of substances is exactly equal to the amount of Cl introduced into the system from the fresh mixture per unit time. - With SO4 2- The ratio of the amount of matter. Crucially, the BMED salt chamber, acting as the "consumption end" of ions, prevents the unlimited accumulation of any ions.

[0020] Among them, the absolute concentration of ions in the mixture (Cl) - 1.5 mol / L~3.0 mol / L, SO4 2- The concentrations (1.2 mol / L to 2.5 mol / L) and the concentration ratio between them are determined and controlled by the following two core operating parameters:

[0021] First, the concentration endpoint of reverse osmosis (i.e., controlling the concentrated brine concentration to be between 8 wt% and 15 wt%) determines the ion load of the circulating stream. Second, the volumetric flow rate ratio of concentrated brine to fresh high-salinity wastewater (1.5~2.5:1) serves as the primary control method. By changing the proportion of circulating materials to fresh materials within the system, the steady-state concentration level is directly adjusted, thereby precisely controlling it within the optimized range. Therefore, even for real high-salinity wastewater with fluctuating ion composition, this invention, through the aforementioned closed-loop design and parameter control, can guide the system to establish and maintain internal homeostasis without the need for an external ion source, ensuring highly stable salt chamber reaction conditions. This is the fundamental guarantee for achieving continuous and efficient production of high-concentration acid-base products.

[0022] Therefore, under steady-state conditions within the system, at least one of the following preferred effects can be achieved:

[0023] Preferably, the relative deviation of the conductivity of the solution at the inlet and outlet of the salt chamber flow channel is ≤5%, for example, 1%, 2%, 3%, 4% or 5%, to characterize good mixing and concentration uniformity within the salt chamber.

[0024] Preferably, the molar concentration of the acid solution produced by the acid chamber is 1.5 mol / L to 3.8 mol / L. Exemplarily, it can be 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L, 2.3 mol / L, 2.4 mol / L, 2.5 mol / L, 2.6 mol / L, 2.7 mol / L, 2.8 mol / L, 2.9 mol / L, 3.0 mol / L, 3.1 mol / L, 3.2 mol / L, 3.3 mol / L, 3.4 mol / L, 3.5 mol / L, 3.6 mol / L, 3.7 mol / L, or 3.8 mol / L, etc.

[0025] Preferably, the molar concentration of the alkaline solution produced in the alkaline chamber is 1.0 mol / L to 2.2 mol / L. Exemplarily, it can be 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.05 mol / L, 2.1 mol / L, or 2.2 mol / L, etc.

[0026] As a preferred embodiment of the present invention, in the bipolar membrane electrodialysis treatment, each salt chamber, together with the adjacent acid and alkali chambers, constitutes a repeating unit. The average voltage of each repeating unit is 1V to 3V, and the number of repeating units is 1 to 200. For example, the average voltage can be 1.0V, 1.3V, 1.6V, 1.8V, 2.0V, 2.3V, 2.5V, 2.8V, or 3.0V, etc.; the number of repeating units can be 1, 5, 10, 30, 50, 80, 100, 130, 150, 180, or 200, etc.

[0027] This invention ensures stable operation of bipolar membrane hydrolysis by matching the number of membrane pairs (the number of repeating units), the applied voltage, and the mixture, thus avoiding damage to the membrane stack or increased energy consumption due to excessive voltage.

[0028] Preferably, in the bipolar membrane electrodialysis treatment, the effective membrane area is 100 cm². 2 ~14000cm 2 For example, it could be 100cm 2 300cm 2 500cm 2 800cm 2 1000cm 2 3000cm 2 5000cm 28000cm 2 10000cm 2 12000cm 2 Or 14000cm 2 wait.

[0029] Preferably, the current density of the bipolar membrane electrodialysis treatment is 40 mA / cm². 2 ~80mA / cm 2 For example, it could be 40mA / cm. 2 42mA / cm 2 44mA / cm 2 46mA / cm 2 48mA / cm 2 50mA / cm 2 55mA / cm 2 60mA / cm 2 65mA / cm 2 70mA / cm 2 75mA / cm 2 or 80mA / cm 2 wait.

[0030] Preferably, the production rate of both acid and alkali solutions is 8L / h to 10L / h, and the energy consumption is 3kWh to 4.15kWh per kilogram of acid solution or 3kWh to 4.15kWh per kilogram of alkali solution. For example, the production rate of acid solution can be 8L / h, 8.5L / h, 9L / h, 9.5L / h, or 10L / h, etc., and the energy consumption can be 3kWh per kilogram of acid solution, 3.3kWh per kilogram of acid solution, 3.5kWh per kilogram of acid solution, 3.8kWh per kilogram of acid solution, 4kWh per kilogram of acid solution, or 4.15kWh per kilogram of acid solution, etc.; the production rate of alkali solution can be 8L / h, 8.5L / h, 9L / h, 9.5L / h, or 10L / h, etc., and the energy consumption can be 3kWh per kilogram of acid solution, 3.3kWh per kilogram of acid solution, 3.5kWh per kilogram of acid solution, 3.8kWh per kilogram of acid solution, 4kWh per kilogram of acid solution, or 4.15kWh per kilogram of acid solution, etc.

[0031] Preferably, the reverse osmosis treatment pressure is less than 5 MPa. For example, it can be 4.8 MPa, 4.5 MPa, 4 MPa, 3.5 MPa, 3 MPa, 2.5 MPa, or 2 MPa, etc.

[0032] Preferably, the energy consumption of the reverse osmosis treatment is 0.8 kWh / m³. 3 ~1.0kWh / m 3 For example, it could be 0.8 kWh / m³. 3 0.85kWh / m 30.88kWh / m 3 0.92kWh / m 3 0.95kWh / m 3 0.98kWh / m 3 or 1kWh / m 3 wait.

[0033] Secondly, the present invention provides a system apparatus for resource-based treatment of high-salinity wastewater, used to operate the method described in the first aspect. The system apparatus includes a bipolar membrane electrodialysis device having a salt chamber, an acid chamber, and an alkali chamber; the salt chamber has a high-salinity wastewater inlet and a brine outlet; the system apparatus further includes an RO reverse osmosis device; the raw water inlet of the RO reverse osmosis device is connected to the brine outlet, and the concentrate outlet of the RO reverse osmosis device is connected to the high-salinity wastewater inlet.

[0034] The system device described in this invention couples the RO reverse osmosis device with the bipolar membrane electrodialysis (BMED) system and designs a completely new operating logic to solve the problem of BMED reaction concentration fluctuation, which is conducive to actively maintaining the high efficiency, low cost and low energy consumption of the reaction system.

[0035] As a preferred embodiment of the present invention, in the bipolar membrane electrodialysis device, an anion exchange membrane is disposed between the salt chamber and the acid chamber, and a cation exchange membrane is disposed between the salt chamber and the alkali chamber, forming a repeating unit; a bipolar membrane is disposed between the acid chamber and the alkali chamber of every two adjacent repeating units, forming a bipolar membrane stack; the outermost acid chamber and alkali chamber of the bipolar membrane stack are respectively the terminal acid chamber and the terminal alkali chamber; the bipolar membrane electrodialysis device further includes an anode and a cathode; the anode is disposed on the terminal acid chamber side of the bipolar membrane stack, and the terminal acid chamber is provided with a terminal acid chamber bipolar membrane corresponding to the anode, and the terminal acid chamber bipolar membrane and the anode form an anode chamber; the cathode is disposed on the terminal alkali chamber side of the bipolar membrane stack, and the terminal alkali chamber is provided with a terminal alkali chamber bipolar membrane corresponding to the cathode, and the terminal alkali chamber bipolar membrane and the cathode form a cathode chamber.

[0036] Preferably, the anion exchange membrane comprises a monovalent selective anion exchange membrane.

[0037] Preferably, the anode includes an anode clamping plate and an anode plate, and the cathode includes a cathode clamping plate and a cathode plate. The anode plate and the cathode plate are respectively connected to the positive and negative terminals of the power supply.

[0038] Preferably, in the bipolar membrane electrodialysis device, there is a partition between adjacent membranes, that is, different membranes are set on both sides of the partition; an effective area (which can be rectangular) is set in the middle of the partition to form a corresponding chamber; three through holes are distributed at intervals on the upper part of the effective area near the edge of the partition, namely acid outlet, raw material salt outlet and alkali outlet, respectively; and three through holes are distributed at intervals on the lower part of the effective area near the edge of the partition, namely alkali inlet, raw material salt inlet and mixed acid inlet, respectively.

[0039] Preferably, the partition is made of PP, PE, or PP / PE composite material.

[0040] For example, the effective area of ​​the spacer between the bipolar membrane and the anion exchange membrane is the acid chamber; the effective area of ​​the spacer between the anion exchange membrane and the cation exchange membrane is the salt chamber; the effective area of ​​the spacer between the cation exchange membrane and the bipolar membrane is the alkali chamber; the anode plate contains the anode chamber; and the cathode plate contains the cathode chamber.

[0041] In each set of repeating units, the acid chamber is connected to the lower acid inlet hole and the upper acid outlet hole; after several sets of repeating units are stacked, the corresponding acid inlets are stacked to form an acid inflow channel, which is connected to the acid inlet of the anode plate; after several sets of repeating units are stacked, the corresponding acid outlet holes are stacked to form an acid outflow channel, which is connected to the acid outlet of the cathode plate.

[0042] In each set of repeating units, the alkali chamber is connected to the alkali inlet at the bottom and to the alkali outlet at the top. After several sets of repeating units are stacked, the corresponding alkali inlets are stacked to form an alkali inflow channel, which is connected to the alkali inlet of the anode plate. After several sets of repeating units are stacked, the corresponding alkali outlets are stacked to form an alkali outflow channel, which is connected to the alkali outlet of the cathode plate.

[0043] Each membrane unit's salt chamber is connected to the lower raw salt inlet and the upper raw salt outlet. After several sets of repeating units are stacked, the corresponding partitions and raw salt inlets are stacked to form a raw salt inflow channel, which is connected to the raw salt inlet of the anode plate (i.e., the salt chamber has a high-salt wastewater inlet). After several sets of repeating units are stacked, the corresponding raw salt outlets are stacked to form a raw salt outflow channel, which is connected to the raw salt outlet of the cathode plate (i.e., the salt chamber has a brine outlet).

[0044] The electrode liquid circulates between the anode chamber and the cathode chamber; the anode plate has an anode chamber inlet and an anode chamber outlet; the cathode clamping plate has a cathode chamber inlet and a cathode chamber outlet on its side; the anode chamber outlet and the cathode plate inlet are connected by a conduit.

[0045] Preferably, the bipolar membrane electrodialysis device includes a DC regulated power supply, an acid circulating water tank, a raw material salt circulating water tank, an alkali circulating water tank, and an electrode liquid circulating water tank.

[0046] For example, the acid solution in the acid circulating water tank enters through the acid inlet and flows back to the acid circulating water tank through the acid outlet; the raw material salt circulating water tank is connected to the raw material salt inlet of the bipolar membrane stack, and the raw material salt solution in the raw material salt circulating water tank enters through the raw material salt inlet and flows back to the raw material salt circulating water tank through the raw material salt outlet; the alkali circulating water tank is connected to the alkali inlet of the bipolar membrane stack, and the alkali solution in the alkali circulating water tank enters through the alkali inlet and flows back to the alkali circulating water tank through the alkali outlet; the electrode liquid circulating water tank is connected to the anode chamber inlet of the bipolar membrane stack, and the electrode liquid in the electrode liquid circulating water tank enters the anode chamber through the anode chamber inlet, then flows out from the anode chamber outlet and flows into the cathode chamber inlet through a conduit, and flows back to the electrode liquid circulating water tank from the cathode chamber outlet.

[0047] It should be noted that, in the initial stage of the method or system device, the acid circulating water tank can be deionized water, and the alkali circulating water tank can be deionized water; the electrode liquid circulating water tank can be an electrode liquid, which may include one or more of sodium sulfate, sodium chloride, sodium nitrate, or sodium hydroxide solutions, with a mass percentage concentration of 1% to 5%; the salt chamber circulating water tank can be a raw material salt solution, which, in addition to the high-salt solution and the mixed solution, can also be initially prepared and used with a simulated salt solution, including sodium chloride and / or sodium sulfate, so that the bipolar membrane dissociates water under the electric field (H2O→H2O). + +OH - This process directly converts NaCl and Na2SO4 into HCl / NaOH and H2SO4 / NaOH.

[0048] As a preferred technical solution of the present invention, the system device further includes a buffer tank, which is disposed between the concentrate outlet of the RO reverse osmosis device and the high-salt wastewater inlet, and is connected to the concentrate outlet of the RO reverse osmosis device, and is provided with a high-salt wastewater inlet.

[0049] Preferably, the buffer tank is equipped with a stirring device, a concentration sensor and / or a pH sensor.

[0050] This invention adds a buffer tank equipped with concentration and pH sensors, allowing for real-time feedback of mixed solution parameters. Furthermore, a PLC control system automatically adjusts the flow rates and mixing ratios of concentrated brine and high-salt wastewater, ensuring the mixed solution concentration and pH value remain stable within the optimized range. Additionally, the outlet piping of the buffer tank can be made of corrosion-resistant PVDF material to reduce pipe resistance.

[0051] For example, the volume of the buffer tank can be 0.5m³. 3 ~4m 3 .

[0052] It should be noted that, due to space limitations and to avoid redundancy, this invention does not exhaustively list all point values ​​within the above numerical range, but it is not limited to the listed values ​​either; other unlisted values ​​within the above numerical range are also applicable.

[0053] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0054] The method for resource-based treatment of high-salinity wastewater described in this invention achieves a closed-loop operation of BMED concentration control, RO concentration, and mixing and recycling of new and old solutions. It constructs a dynamic process control and circulation enhancement strategy, which not only recovers residual salt and fresh water through RO reverse osmosis, realizing the internal recycling of salt and water resources and reducing waste discharge and fresh raw material consumption, but also allows for continuous recycling of the mixed liquor. This improves the concentration bottleneck problem in BMED treatment, significantly reduces system resistance and energy consumption per unit of acid production, and significantly increases the concentration of produced acid and alkali, achieving a high resource utilization rate. Attached Figure Description

[0055] Figure 1 This is a process flow diagram of the resource-based treatment method for high-salinity wastewater provided in Example 2.

[0056] Figure 2 This is a schematic diagram of the system device for resource-based treatment of high-salinity wastewater provided in Example 1.

[0057] Figure 3 This is a schematic diagram of the bipolar membrane stack in the bipolar membrane electrodialysis device of Example 1.

[0058] Figure 4 This is a schematic diagram of the partition in the bipolar membrane electrodialysis device in Example 1.

[0059] Figure 5 This is a schematic diagram of the buffer tank in Example 1.

[0060] In the diagram, 1-DC regulated power supply; 2-Bipolar membrane stack; 3-Electrode liquid circulation tank; 4-Acid circulation tank; 5-Raw material salt circulation tank; 6-Alkali circulation tank; 7-Electrode liquid magnetic circulation drive pump; 8-Acid liquid magnetic circulation drive pump; 9-Raw material salt solution magnetic circulation drive pump; 10-Alkali solution magnetic circulation drive pump; 11-Cathode chamber inlet; 12-Anode chamber inlet; 13-Alkali inlet; 14-High salinity wastewater inlet; 15-Acid inlet; 16-Alkali outlet; 17-Dilute brine outlet; 18-Acid outlet; 19-Anode chamber outlet; 20-Cathode chamber outlet; 30-Buffer tank; 31-pH sensor; 32-Concentration sensor; 33-High salinity wastewater inlet; 34-RO concentrate inlet; 35-Mixed solution outlet. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] Example 1

[0063] This embodiment provides a system device for the resource-based treatment of high-salinity wastewater, such as... Figures 2 to 5 As shown, the system includes a bipolar membrane electrodialysis (BMED) device with a salt chamber, an acid chamber, and an alkali chamber; the salt chamber has a volume of 2L and has a high-salt wastewater inlet 14 and a desalinated water outlet 17; the system also includes an RO reverse osmosis device with a raw water inlet and a concentrate outlet; the raw water inlet of the RO reverse osmosis device is connected to the desalinated water outlet 17; the system also includes a buffer tank 30 with an RO concentrate inlet 34, a high-salt wastewater inlet 33, and a mixed liquor outlet 35; the concentrate outlet of the RO reverse osmosis device is connected to the RO concentrate inlet 34 of the buffer tank 30, and the mixed liquor outlet 35 of the buffer tank 30 is connected to the high-salt wastewater inlet 14 of the salt chamber.

[0064] Specifically, in the bipolar membrane electrodialysis device, an anion exchange membrane is disposed between the salt chamber and the acid chamber, and a cation exchange membrane is disposed between the salt chamber and the alkali chamber, forming a repeating unit; a bipolar membrane is disposed between the acid chamber and the alkali chamber of every two adjacent repeating units, and a total of 10 repeating units are formed, constituting a bipolar membrane stack 2; the outermost acid chamber and alkali chamber of the bipolar membrane stack 2 are respectively the terminal acid chamber and the terminal alkali chamber. The bipolar membrane electrodialysis device also includes an anode and a cathode. The anode is disposed on the terminal acid chamber side of the bipolar membrane stack 2, and the terminal acid chamber is provided with a terminal acid chamber bipolar membrane corresponding to the anode. The negative side of the terminal acid chamber bipolar membrane and the anode form an anode chamber; the cathode is disposed on the terminal alkali chamber side of the bipolar membrane stack 2, and the terminal alkali chamber is provided with a terminal alkali chamber bipolar membrane corresponding to the cathode. The positive side of the terminal alkali chamber bipolar membrane and the cathode form a cathode chamber. The anode includes an anode clamping plate and an anode plate, and the cathode includes a cathode clamping plate and a cathode plate. The anode plate and cathode plate are connected to the positive and negative terminals of the DC regulated power supply 1, respectively.

[0065] The bipolar membrane, cation exchange membrane, and anion exchange membrane involved in this embodiment are all commercially available and known materials. Specifically: the bipolar membrane is model BP-2 (Sens Environmental Technology Co., Ltd.); the cation exchange membrane is model CT-4 (Sens Environmental Technology Co., Ltd.); and the anion exchange membrane is model AHT (Sens Environmental Technology Co., Ltd.). The effective area of ​​all the above membranes is 104 cm². 2For example, the following other manufacturers and models of membranes can also achieve the effects of the present invention: the bipolar membrane can be the TRJBM bipolar membrane from Beijing Yanrun Membrane Technology Development Co., Ltd., the BPM bipolar membrane from Liaoning Yichen Membrane Technology Co., Ltd., or the TWBPI bipolar membrane from Shandong Tianwei Membrane Technology Co., Ltd.; the anion exchange membrane can be the TRJBM anion exchange membrane from Beijing Yanrun Membrane Technology Development Co., Ltd., the LAM anion exchange membrane from Liaoning Yichen Membrane Technology Co., Ltd.; or the TWEDAI anion exchange membrane from Shandong Tianwei Membrane Technology Co., Ltd.; the cation exchange membrane can be the cation exchange membrane of Beijing Yanrun Membrane Technology Development Co., Ltd., the LCM cation exchange membrane from Liaoning Yichen Membrane Technology Co., Ltd., the TWEDCI cation exchange membrane from Shandong Tianwei Membrane Technology Co., Ltd.; or the CMB cation exchange membrane from ASTOM Corporation; the above are merely examples and are not limited thereto.

[0066] Furthermore, such as Figure 4As shown, in the bipolar membrane electrodialysis device, adjacent membranes are separated by a partition, meaning different membranes are arranged on both sides of the partition. The effective area in the middle of the partition is rectangular, forming corresponding chambers. Three through-holes are spaced apart near the upper edge of the effective area, namely, an acid outlet, a feed salt outlet, and an alkali outlet. Simultaneously, three through-holes are spaced apart near the lower edge of the effective area, namely, an alkali inlet, a feed salt inlet, and a mixed acid inlet. The partition is made of PE; that is, the partition between the bipolar membrane and the anion exchange membrane... The effective area is the acid chamber; the effective area of ​​the partition between the anion exchange membrane and the cation exchange membrane is the salt chamber; the effective area of ​​the partition between the cation exchange membrane and the bipolar membrane is the alkali chamber; the anode plate contains the anode chamber; the cathode plate contains the cathode chamber; in each set of repeating units, the acid chamber communicates with the lower acid inlet and the upper acid outlet; after several sets of repeating units are stacked, the corresponding acid inlets are stacked to form an acid inflow channel, which is connected to the acid inlet 15 of the anode plate; after several sets of repeating units are stacked, the corresponding acid outlets are stacked to form an acid outflow channel, which is connected to the acid outlet 15 of the cathode plate. The outlet 18 is connected; in each set of repeating units, the alkali chamber is connected to the lower alkali inlet and the upper alkali outlet; after several sets of repeating units are stacked, the corresponding alkali inlets are stacked to form an alkali inflow channel, which is connected to the alkali inlet 13 of the anode plate; after several sets of repeating units are stacked, the corresponding alkali outlets are stacked to form an alkali outflow channel, which is connected to the alkali outlet 16 of the cathode plate; the salt chamber of each membrane unit is connected to the lower raw material salt inlet and the upper raw material salt outlet; after several sets of repeating units are stacked, the corresponding partitions are stacked to form... A raw salt inflow channel is formed, which is connected to the raw salt inlet of the anode plate (i.e., the salt chamber has a high-salt wastewater inlet 14); after several sets of repeating units are stacked, the corresponding raw salt outlet holes are stacked to form a raw salt outflow channel, which is connected to the raw salt outlet of the cathode plate (i.e., the salt chamber has a brine outlet 17); the electrode liquid circulates in the anode chamber and the cathode chamber; there are anode chamber inlets and anode chamber outlets 19 on the anode plate; there are cathode chamber inlets 11 and cathode chamber outlets 20 on the side of the cathode clamping plate; the anode chamber outlet 19 is connected to the cathode plate inlet through a conduit.

[0067] The bipolar membrane electrodialysis device includes a DC regulated power supply 1, an acid circulating water tank 4, a raw material salt circulating water tank 5, an alkali circulating water tank 6, and an electrode liquid circulating water tank 3. The DC regulated power supply 1 is used to form a typical connection with the anode and cathode plates; the acid circulating water tank 4 stores the initial solution or acid, is connected to the acid inlet 15 for entry, and an acid magnetic circulation pump 8 is installed on the pipeline connected to the acid inlet 15. Simultaneously, the acid circulating water tank 4 is connected to the acid outlet 18, thereby allowing acid to flow back to the acid circulating water tank 4; the alkali circulating water tank 6 is connected to the alkali inlet 13 of the bipolar membrane stack 2, and the initial solution or alkali in the alkali circulating water tank 6 enters through the alkali inlet 13. An alkali magnetic circulation pump 10 is installed on the pipeline connected to the alkali inlet 13, and simultaneously, the alkali circulating water tank 6 is connected to the alkali outlet 16, thereby allowing alkali to flow back to the alkali circulating water tank 6; the electrode liquid circulating water tank 3 is connected to the anode chamber inlet of the bipolar membrane stack 2, and the electrode liquid circulating water tank 3... The electrode solution enters the anode chamber through the anode chamber inlet, then flows out from the anode chamber outlet 19 and is connected to the cathode chamber inlet 11 via a conduit, and flows back to the electrode solution circulation tank 3 from the cathode chamber outlet 20. The raw material salt circulation tank 5 is connected to the raw material salt inlet (i.e., high-salt wastewater inlet 14) of the bipolar membrane stack 2. The raw material salt solution (high-salt wastewater and mixed liquor, etc.) in the raw material salt circulation tank 5 enters through the raw material salt inlet, and a magnetic circulation pump 9 for the raw material salt solution is installed on the pipeline connected to the raw material salt inlet. At the same time, the raw material salt circulation tank 5 is connected to the raw material salt outlet (i.e., desalinated water outlet 17). Specifically, the desalinated water outlet 17 of the membrane stack is first connected to the raw water inlet of the RO reverse osmosis unit through a high-pressure pump, and then connected to the buffer tank 30 (with a volume of 0.8 m³) through the concentrate outlet. 3 The RO concentrate inlet 34 and the buffer tank 30 have a high-salt wastewater inlet 33, so that the high-salt wastewater and concentrated brine are mixed in the buffer tank 30, and then connected to the raw material salt circulating water tank 5 through the mixed liquid outlet 35 of the buffer tank 30. The buffer tank 30 is also equipped with a stirring device, a concentration sensor 32 and a pH sensor 31.

[0068] It should be noted that, in the initial stage of operation of the system, the initial solution in the acid circulating water tank 4 can be deionized water, and the initial solution in the alkali circulating water tank 6 can be deionized water; the polar liquid circulating water tank 3 can be the polar liquid, which may include one or more of sodium sulfate, sodium chloride, sodium nitrate or sodium hydroxide solutions, and the mass concentration of the polar liquid is 1% to 5%; the salt chamber circulating water tank can be the raw material salt solution, which, in addition to the high-salt solution and the mixed solution, can also be prepared and used as a simulated salt solution at the beginning, which includes sodium chloride and / or sodium sulfate.

[0069] Example 2

[0070] This embodiment provides a method for the resource-based treatment of high-salinity wastewater, using the system apparatus of Embodiment 1, such as... Figure 1As shown, it includes the following steps:

[0071] (1) Add the corresponding solutions to each circulating water tank: add a simulated salt solution with a mass percentage concentration of 17% to the salt chamber circulating water tank, and add sodium chloride and sodium sulfate with a molar ratio of chloride ions to sulfate ions of 1:1 to the simulated salt solution; add pure water as the initial solution to the acid circulating water tank; add pure water as the initial solution to the alkali circulating water tank; add a sodium hydroxide solution with a mass percentage concentration of 3% to the polar liquid circulating water tank;

[0072] (2) Turn on each circulating water pump and adjust the feed flow rate of each circulating water tank to 1.5 L / (min·m). 2 This allows the solution to remain in the corresponding chamber for 80 seconds.

[0073] (3) Turn on the DC regulated power supply and adjust the voltage so that the average voltage of each repeating unit is 2.2V and the total voltage is 22V;

[0074] (4) The solution is circulated between the circulating water tank and the membrane stack for bipolar membrane electrodialysis treatment. The concentration of the discharged brine is monitored by conductivity. When the concentration (conductivity) of the brine in the raw material salt circulating water tank drops to 11.3wt% (i.e. 66.6%), the brine is continuously discharged into the RO reverse osmosis unit.

[0075] (5) Reverse osmosis treatment is carried out in the RO reverse osmosis device, and the treatment pressure is controlled to be less than 5MPa to obtain concentrated brine with a mass concentration of 8wt%~15wt%. Then, the concentrated brine is continuously discharged into the buffer tank. The RO reverse osmosis device also produces pure water through reverse osmosis treatment. The pure water can be stored and used as the initial solution added to the acid circulating water tank and alkali circulating water tank in the bipolar membrane electrodialysis device.

[0076] (6) At the same time as the concentrated brine enters the buffer tank, high-salt wastewater with a mass percentage concentration of 17% is added through the high-salt wastewater inlet of the buffer tank, and the mixed liquid is formed by parallel flow at a volume flow ratio of 2:1; the high-salt wastewater comes from the by-product miscellaneous salt mother liquor of coal chemical wastewater; through internal circulation and process control of the system, the chloride ion concentration in the mixed liquid entering the salt chamber is controlled at 1.5mol / L~3.0mol / L, and the sulfate ion concentration is controlled at 1.2mol / L~2.5mol / L, so that the chloride ion and sulfate ion concentrations in the mixed liquid are stabilized at 1:1;

[0077] (7) The resulting mixture is then discharged from the buffer tank and sent to the raw material salt circulating water tank. Steps (4) to (7) are repeated to continuously cycle the bipolar membrane electrodialysis treatment.

[0078] Example 3

[0079] The difference between Example 3 and Example 2 is that the amounts of sodium chloride and sodium sulfate are adjusted so that the concentration ratio of chloride ions to sulfate ions in the simulated salt solution in step (1) is changed from 1:1 to 1:2. Apart from the above, the other conditions are exactly the same as in Example 1.

[0080] Example 4

[0081] The difference between Example 4 and Example 2 is that the amounts of sodium chloride and sodium sulfate are adjusted so that the concentration ratio of chloride ions to sulfate ions in the simulated salt solution in step (1) is changed from 1:1 to 2:1. Apart from the above, the other conditions are exactly the same as in Example 1.

[0082] Example 5

[0083] The difference between Example 5 and Example 2 is that the average voltage of each repeating unit in step (3) is adjusted from 2.2V to 1.8V, that is, the total voltage is adjusted from 22V to 18V. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 2 is that the mass percentage concentration of the simulated salt solution in step (1) was adjusted from 17% to 12%, and the mass percentage concentration of the high-salt wastewater in step (1) was also adjusted from 17% to 12%. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 2 is that the mass percentage concentration of the simulated salt solution in step (1) was adjusted from 17% to 21%, and the mass percentage concentration of the high-salt wastewater in step (1) was also adjusted from 17% to 21%. Apart from the above, the other conditions are exactly the same as in Example 1.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 3 and Example 2 is that the concentration discharge point of the brine in the raw material salt circulation tank in step (4) is adjusted from 11.3wt% to 8.5wt% (i.e. 50% of the initial concentration). Apart from the above, the other conditions are exactly the same as those in Example 1.

[0090] Comparative Example 4

[0091] The difference between Comparative Example 4 and Example 2 is that the concentration discharge point of the brine in the raw material salt circulating tank in step (4) is adjusted from 11.3wt% to 12.75wt% (i.e. 75% of the initial concentration). Apart from the above, the other conditions are exactly the same as those in Example 1.

[0092] Comparative Example 5

[0093] The difference between Comparative Example 5 and Example 2 is that the concentration of the concentrated brine obtained after RO reverse osmosis treatment in step (5) was adjusted from 10wt% to 5wt%. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0094] Comparative Example 6

[0095] The difference between Comparative Example 6 and Example 2 is that the concentration of the concentrated brine obtained after RO reverse osmosis treatment in step (5) was adjusted from 10wt% to 18wt%. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0096] Comparative Example 7

[0097] The difference between Comparative Example 7 and Example 2 is that the volume flow ratio of concentrated brine to high-salt wastewater in step (6) is adjusted from 2:1 to 1:1. Apart from the above, the other conditions are exactly the same as those in Example 1.

[0098] control group

[0099] This control group provides a method for resource-based treatment of high-salinity wastewater, using the system apparatus of Example 1, but shutting down the RO reverse osmosis treatment device and buffer tank in Example 1, and only using the bipolar membrane electrodialysis device, continuously adding high-salinity wastewater to the raw material salt circulating water tank for direct bipolar membrane electrodialysis treatment. Except for the above, other conditions are exactly the same as in Example 1.

[0100] Results and Comparison:

[0101] The treatment results and effects of each embodiment, comparative example, and control group were monitored, and the results are shown in Table 1:

[0102] Table 1

[0103]

[0104] Experimental results show that under optimized process parameters (high-salt wastewater concentration of 17 wt%, brine discharge concentration of 11.3 wt%, RO concentration of 10 wt%, mixing volume ratio of 2:1, salt chamber residence time of 80 s, and unit average voltage of 2.2 V), the system of this invention exhibits optimal comprehensive performance: current density reaches 65 mA / cm², brine utilization rate is as high as 93%, and the produced acid and alkali concentrations are 3.2 mol / L and 1.9 mol / L, respectively, corresponding to energy consumption of only 3.1 kWh / kg and 3.0 kWh / kg, with RO energy consumption as low as 0.85 kWh / m³. Comparative analysis confirms that deviations of key parameters (such as feed concentration, ion ratio, residence time, voltage, brine discharge point, RO concentration, and mixing ratio) from the optimized range set by this invention will lead to a decrease in performance indicators (such as utilization rate and product concentration) and a significant increase in energy consumption.

[0105] Compared with the conventional BMED control group, the method and system device described in this invention, after inheriting RO reverse osmosis, can achieve the following advantages: brine utilization rate can be increased by 30%~50%, reaching 90%~95%; acid and alkali production energy consumption can be reduced by 30%~35%, reaching 3kWh~4.15kWh per kilogram of acid or alkali; system operating cost can be reduced by 38%~47%, reaching 80~90 yuan per ton of acid or alkali; membrane stack life can be extended by more than 50%, reaching 3 years~3.5 years.

[0106] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0107] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0108] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for resource-based treatment of high-salinity wastewater, characterized in that, The method includes: A bipolar membrane electrodialysis apparatus is provided, comprising a salt chamber, an acid chamber, and an alkali chamber; high-salt wastewater with a mass concentration of 5wt% to 20wt% is continuously supplied to the salt chamber for bipolar membrane electrodialysis treatment, and a dilute brine with a mass concentration of 2.5wt% to 13.4wt% is continuously discharged. The brine is subjected to reverse osmosis treatment to obtain a concentrated brine with a mass concentration of 8wt%~15wt%; the concentrated brine and the high-salt wastewater are mixed in parallel at a volume flow ratio of (1.5~2.5):1 to form a mixed solution, and the mixed solution is continuously circulated to the salt chamber for the bipolar membrane electrodialysis treatment.

2. The method for resource-based treatment of high-salinity wastewater according to claim 1, characterized in that, The high-salinity wastewater includes by-product salt mother liquor from coal chemical wastewater.

3. The method for resource-based treatment of high-salinity wastewater according to claim 1 or 2, characterized in that, The method, through internal system circulation and process control, maintains the chloride ion concentration in the mixed solution entering the salt chamber at 1.5 mol / L~3.0 mol / L and the sulfate ion concentration at 1.2 mol / L~2.5 mol / L, and maintains the chloride ion to sulfate ion molar ratio at (0.75~1.33):1; wherein the internal circulation and process control includes: The fresh brine discharged from bipolar membrane electrodialysis is subjected to reverse osmosis treatment to obtain concentrated brine with a mass concentration of 8wt%~15wt%. The concentrated brine is then mixed with the high-salt wastewater at a volume flow rate ratio of (1.5~2.5):1 to form a new mixed solution. By controlling the mass concentration of the concentrated brine and the volume flow rate ratio, the system reaches and maintains a dynamic steady state, thereby controlling and maintaining the ion concentration and ratio of chloride and sulfate ions in the mixed solution.

4. The method for resource-based treatment of high-salinity wastewater according to any one of claims 1-3, characterized in that, The molar concentration of the acid solution produced by the acid chamber is 1.5 mol / L to 3.8 mol / L; Preferably, the molar concentration of the alkaline solution produced by the alkaline chamber is 1.0 mol / L to 2.2 mol / L.

5. The method for resource-based treatment of high-salinity wastewater according to any one of claims 1-4, characterized in that, In the bipolar membrane electrodialysis process, each salt chamber, together with the adjacent acid and alkali chambers, constitutes a repeating unit. The average voltage of each repeating unit is 1V to 3V, and the number of repeating units is 1 to 200. Preferably, the current density of the bipolar membrane electrodialysis treatment is 40 mA / cm². 2 ~80mA / cm 2 ; Preferably, in the bipolar membrane electrodialysis treatment, the effective membrane area is 100 cm². 2 ~14000cm 2 .

6. The method for resource-based treatment of high-salinity wastewater according to any one of claims 1-5, characterized in that, The reverse osmosis treatment pressure is less than 5 MPa.

7. A system device for resource-based treatment of high-salinity wastewater, characterized in that, The apparatus is used to implement the method according to any one of claims 1-6. The system apparatus includes a bipolar membrane electrodialysis device having a salt chamber, an acid chamber, and an alkali chamber; the salt chamber has a high-salt wastewater inlet and a desalinated water outlet; the system apparatus further includes an RO reverse osmosis device having a raw water inlet and a concentrate outlet; the raw water inlet of the RO reverse osmosis device is connected to the desalinated water outlet; the system apparatus further includes a buffer tank having an RO concentrate inlet, a high-salt wastewater inlet, and a mixed liquor outlet; the concentrate outlet of the RO reverse osmosis device is connected to the RO concentrate inlet of the buffer tank, and the mixed liquor outlet of the buffer tank is connected to the high-salt wastewater inlet of the salt chamber.

8. The system apparatus for resource-based treatment of high-salinity wastewater according to claim 7, characterized in that, In the bipolar membrane electrodialysis device, an anion exchange membrane is disposed between the salt chamber and the acid chamber, and a cation exchange membrane is disposed between the salt chamber and the alkali chamber, forming a repeating unit; a bipolar membrane is disposed between the acid chamber and the alkali chamber of every two adjacent repeating units, forming a bipolar membrane stack; the outermost acid chamber and alkali chamber of the bipolar membrane stack are respectively the terminal acid chamber and the terminal alkali chamber; the bipolar membrane electrodialysis device also includes an anode and a cathode; the anode is disposed on the terminal acid chamber side of the bipolar membrane stack, and the terminal acid chamber is provided with a terminal acid chamber bipolar membrane corresponding to the anode, and the terminal acid chamber bipolar membrane and the anode form an anode chamber; the cathode is disposed on the terminal alkali chamber side of the bipolar membrane stack, and the terminal alkali chamber is provided with a terminal alkali chamber bipolar membrane corresponding to the cathode, and the terminal alkali chamber bipolar membrane and the cathode form a cathode chamber.

9. The system apparatus for resource-based treatment of high-salinity wastewater according to claim 8, characterized in that, The anion exchange membrane includes a monovalent selective anion exchange membrane.

10. The system apparatus for resource-based treatment of high-salinity wastewater according to any one of claims 7-9, characterized in that, The buffer tank is equipped with a stirring device, as well as a concentration sensor and / or pH sensor.

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