A high concentration ammonium sulfate wastewater treatment system

Abstract

The application discloses a high-concentration ammonium sulfate wastewater treatment system and relates to the technical field of industrial wastewater treatment. A polar water circulating pump drives polar water to circulate between an anode chamber / cathode chamber and a polar water circulating tank, a brine circulating pump drives ammonium sulfate wastewater to circulate between a salt chamber and a brine circulating tank, an alkali circulating pump maintains fluid circulation between an alkali chamber and an alkali circulating tank, an acid circulating pump maintains fluid circulation between an acid chamber and an acid circulating tank, and the acid chamber receives and combines to generate, and the alkali chamber receives and combines to generate. Compared with a traditional process which relies on high temperature and has high energy consumption, the application utilizes electric field force to drive ion migration and recombination, only needs to maintain low-voltage direct current, and has low energy consumption. Ammonium sulfate is converted into sulfuric acid and ammonia water, both of which are high-value-added products, nearly realize zero discharge, avoid secondary pollution, and improve resource utilization. Through electrochemical separation, direct desalination is not limited by microbial activity, and the treatment efficiency can be improved.

Description

Technical Field

[0001] This application relates to the field of industrial wastewater treatment technology, and in particular to a high-concentration ammonium sulfate wastewater treatment system. Background Technology

[0002] Ammonium sulfate wastewater is a typical difficult-to-treat wastewater generated by industries such as fertilizers, pharmaceuticals, dyes, petrochemicals, and coal chemicals. It has three major treatment challenges: high salinity (ammonium sulfate concentration often reaches 10%-25%), which leads to osmotic pressure imbalance and crystallization blockage; high nitrogen load (total nitrogen > 5000 mg / L), which easily causes eutrophication of water bodies; and complex impurities (containing organic matter, heavy metals, colloids, etc.), which interfere with the stability of treatment units.

[0003] Currently, commonly used ammonium sulfate wastewater treatment processes include high-temperature incineration, deep well injection, evaporation crystallization, and biological treatment. High-temperature incineration involves burning the ammonium sulfate wastewater in a high-temperature incinerator using fuel, causing the organic matter to oxidize and decompose. This process consumes a large amount of energy and is prone to producing pollutants. Ammonium sulfate wastewater contains secondary pollutants such as sulfur dioxide and ammonium salt residue. Deep well injection involves injecting the wastewater into permeable underground rock formations under pressure, but this only transfers the pollutants and cannot address the root cause of environmental pollution. Evaporation crystallization separates ammonium sulfate from the wastewater through continuous evaporation, but this method is energy-intensive and prone to scaling. Biological treatment relies on microorganisms to degrade organic matter, but high-salt environments inhibit microbial activity, leading to low treatment efficiency. It often requires wastewater dilution, increasing the volume and cost of treated water and potentially affecting the stability of microbial metabolites. Therefore, existing methods for treating high-concentration ammonium sulfate wastewater mainly suffer from high energy consumption, secondary pollution, low treatment efficiency, and low resource recovery rates.

[0004] Therefore, how to reduce the energy consumption of ammonium sulfate wastewater treatment, avoid secondary pollution, and improve treatment efficiency and resource utilization are problems that need to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this application is to provide a high-concentration ammonium sulfate wastewater treatment system to solve the problems of high energy consumption, easy generation of secondary pollution, low treatment efficiency and low resource recovery rate in existing high-concentration ammonium sulfate wastewater treatment.

[0006] To solve the above-mentioned technical problems, this application provides a high-concentration ammonium sulfate wastewater treatment system, including: a bipolar membrane electrodialysis device, a brine circulating water tank storing ammonium sulfate wastewater, a brine circulating pump, an alkali circulating water tank, an alkali circulating pump, an acid circulating water tank, an acid circulating pump, an electrode water circulating water tank, and an electrode water circulating pump.

[0007] The bipolar membrane electrodialysis device includes an anode plate, a functional chamber, and a cathode plate. The functional chamber includes a first bipolar membrane, an anion exchange membrane, a cation exchange membrane, and a second bipolar membrane, which are spaced apart along the anode plate to the cathode plate. The anode chamber is located between the anode plate and the first bipolar membrane. The acid chamber is located between the first bipolar membrane and the anion exchange membrane. The salt chamber is located between the anion exchange membrane and the cation exchange membrane. The alkali chamber is located between the cation exchange membrane and the second bipolar membrane. The cathode chamber is located between the second bipolar membrane and the cathode plate. The brine circulation tank is connected to the inlet and outlet of the salt chamber via the brine circulation pump. The alkali circulation tank is connected to the inlet and outlet of the alkali chamber via the alkali circulation pump. The acid circulation tank is connected to the inlet and outlet of the acid chamber via the acid circulation pump. The polar water circulation tank is connected to the inlet and outlet of the anode chamber and the inlet and outlet of the cathode chamber via the polar water circulation pump.

[0008] In one feasible embodiment, the system further includes a dilute acid delivery pump, a first heat exchanger, a sulfuric acid distillation column, a concentrated acid delivery pump, and a high-concentration sulfuric acid tank. The dilute acid delivery pump is connected to the acid circulation tank and the first inlet of the first heat exchanger, respectively. The first outlet of the first heat exchanger is connected to the inlet of the sulfuric acid distillation column. The outlet of the sulfuric acid distillation column is connected to the second inlet of the first heat exchanger via the concentrated acid delivery pump. The second outlet of the first heat exchanger is connected to the high-concentration sulfuric acid tank.

[0009] In one feasible embodiment, the system further includes a dilute alkali transfer pump, a second heat exchanger, an ammonia distillation column, and a high-concentration ammonia water tank. The dilute alkali transfer pump is connected to the alkali circulation tank and the first inlet of the second heat exchanger, respectively. The first outlet of the second heat exchanger is connected to the inlet of the ammonia distillation column, the top outlet of the ammonia distillation column is connected to the second inlet of the second heat exchanger, and the second outlet of the second heat exchanger is connected to the high-concentration ammonia water tank.

[0010] In one feasible embodiment, the system further includes a reverse osmosis feed booster pump and a security filter, wherein the reverse osmosis feed booster pump is connected to the brine circulation tank and the security filter, respectively.

[0011] In one feasible embodiment, the system further includes a reverse osmosis feed high-pressure pump, an RO membrane device, and an RO permeate tank. The reverse osmosis feed high-pressure pump is connected to the security filter and the RO membrane device, respectively. The RO permeate tank is connected to the permeate outlet of the RO membrane device, and the concentrate outlet of the RO membrane device is connected to the brine circulating water tank.

[0012] In one feasible embodiment, the system further includes an online reverse osmosis feed water conductivity meter and an online reverse osmosis permeate conductivity meter. The online reverse osmosis feed water conductivity meter is installed on the pipeline connecting the brine circulating water tank and the security filter, and the online reverse osmosis permeate conductivity meter is installed on the pipeline connecting the RO membrane device and the RO permeate tank.

[0013] In one feasible embodiment, the system further includes a reverse osmosis permeate flow meter and a reverse osmosis concentrate flow meter. The reverse osmosis permeate flow meter is installed on the pipeline connecting the RO membrane device and the RO permeate tank, and the reverse osmosis concentrate flow meter is installed on the pipeline connecting the RO membrane device and the brine circulating water tank.

[0014] In one feasible embodiment, the RO permeate tank is also connected to the alkaline circulating water tank and the acid circulating water tank, respectively.

[0015] In one feasible embodiment, a pretreatment device is also included, which is connected to the brine circulating tank.

[0016] In one feasible embodiment, there are multiple functional chambers, and the acid chamber of one functional chamber and the alkali chamber of another functional chamber in two adjacent functional chambers share a bipolar membrane.

[0017] This application provides a high-concentration ammonium sulfate wastewater treatment system, in which an electrode water circulation pump drives electrode water to circulate between the anode / cathode chamber and the electrode water circulation tank; a brine circulation pump drives ammonium sulfate wastewater to circulate between the brine chamber and the brine circulation tank; an alkali circulation pump maintains fluid circulation between the alkali chamber and the alkali circulation tank; and an acid circulation pump maintains fluid circulation between the acid chamber and the acid circulation tank. The acid chamber receives... Dissociated from the first bipolar membrane Combined generation Alkali chamber receiving Dissociation from the second bipolar membrane Combined generation Compared to traditional processes (such as incineration and evaporation) that rely on high temperatures and pressures and have high energy consumption, bipolar membrane electrodialysis equipment uses electric field force to directly drive ion migration and recombination, requiring only low-voltage direct current to effectively reduce energy consumption. Ammonium sulfate is converted into sulfuric acid and ammonia, both of which are high-value-added products, achieving near-zero discharge, effectively avoiding secondary pollution and improving resource utilization. Bipolar membrane electrodialysis equipment directly desalinates through electrochemical separation, is not limited by microbial activity, and can improve treatment efficiency. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A structural diagram of a high-concentration ammonium sulfate wastewater treatment system provided in this application embodiment;

[0020] Figure 2 This is a schematic diagram of a bipolar membrane electrodialysis device provided in an embodiment of this application.

[0021] The attached diagram is labeled as follows: 1-Bipolar membrane electrodialysis equipment, 2-Brine circulating water tank, 3-Brine circulating pump, 4-Alkali circulating water tank, 5-Alkali circulating pump, 6-Acid circulating water tank, 7-Acid circulating pump, 8-Electrode water circulating water tank, 9-Electrode water circulating pump, 10-Dilute acid transfer pump, 11-First heat exchanger, 12-Sulfuric acid distillation column, 13-Concentrated acid transfer pump, 14-High-concentration sulfuric acid water tank, 15-Dilute alkali transfer pump, 16-Second heat exchanger, 17-Ammonia distillation column, 18-High-concentration ammonia water tank, 19-Reverse osmosis feed booster pump, 20-Security filter, 21-Reverse osmosis High-pressure inlet pump, 22-RO membrane unit, 23-RO permeate tank, 24-online reverse osmosis feed water conductivity meter, 25-online reverse osmosis permeate conductivity meter, 26-reverse osmosis permeate flow meter, 27-reverse osmosis concentrate flow meter, 101-anode plate, 102-functional chamber, 103-cathode plate, 1021-first bipolar membrane, 1022-anion exchange membrane, 1023-cation exchange membrane, 1024-second bipolar membrane, 1025-anode chamber, 1026-acid chamber, 1027-salt chamber, 1028-alkali chamber, 1029-cathode chamber. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0023] The core of this application is to provide a high-concentration ammonium sulfate wastewater treatment system, which reduces energy consumption in ammonium sulfate wastewater treatment, avoids secondary pollution, and improves treatment efficiency and resource utilization.

[0024] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 A structural diagram of a high-concentration ammonium sulfate wastewater treatment system provided in this application embodiment is shown below. Figure 1 As shown, the high-concentration ammonium sulfate wastewater treatment system includes a bipolar membrane electrodialysis device 1, a brine circulating water tank 2 storing ammonium sulfate wastewater, a brine circulating pump 3, an alkali circulating water tank 4, an alkali circulating pump 5, an acid circulating water tank 6, an acid circulating pump 7, an electrode water circulating water tank 8, and an electrode water circulating pump 9. The bipolar membrane electrodialysis device 1 includes an anode plate 101, a functional chamber 102, and a cathode plate 103. The functional chamber 102 includes a first bipolar membrane 1021, an anion exchange membrane 1022, a cation exchange membrane 1023, and a second bipolar membrane 1024, which are spaced apart along the anode plate 101 to the cathode plate 103. The anode chamber 1025 is located between the anode plate 101 and the first bipolar membrane 1021. The first bipolar membrane 1021 and the first bipolar membrane 1024 are connected in series. An acid chamber 1026 is located between anion exchange membranes 1022 and cation exchange membranes 1023; a salt chamber 1027 is located between anion exchange membranes 1022 and cation exchange membranes 1023; an alkali chamber 1028 is located between cation exchange membranes 1023 and the second bipolar membrane 1024; and a cathode chamber 1029 is located between the second bipolar membrane 1024 and the cathode plate 103. A brine circulation tank 2 is connected to the inlet and outlet of the salt chamber 1027 via a brine circulation pump 3. An alkali circulation tank 4 is connected to the inlet and outlet of the alkali chamber 1028 via an alkali circulation pump 5. An acid circulation tank 6 is connected to the inlet and outlet of the acid chamber 1026 via an acid circulation pump 7. An electrode water circulation tank 8 is connected to the inlet and outlet of the anode chamber 1025 and the inlet and outlet of the cathode chamber 1029 via an electrode water circulation pump 9.

[0026] The bipolar membrane electrodialysis device 1 in this application mainly achieves the following molecular recombination: This means achieving efficient and clean conversion and recovery of salts (ammonium sulfate) in ammonium sulfate wastewater into high-value-added acid and alkali products (sulfuric acid and ammonia).

[0027] In this embodiment, the anode plate 101 provides a positive potential, and under the action of a DC electric field, drives the electrolytic reaction in the anode chamber 1025 (e.g., The cathode plate 103 provides a negative potential, which, under the action of a DC electric field, drives the electrolytic reaction in the cathode chamber 1029 (e.g., Salt anions Dissociation via anion exchange membrane 1022 and first bipolar membrane 1021 Combined generation Salt cations Dissociation through cation exchange membrane 1023 and second bipolar membrane 1024 Combined generation The brine circulating tank 2 stores ammonium sulfate wastewater (15-20 wt%), which is continuously pumped into the salt chamber 1027 by the brine circulating pump 3 to provide reaction raw materials. The outlet of the brine circulating tank 2 is connected to the inlet of the salt chamber 1027 via the brine circulating pump 3, and the outlet of the salt chamber 1027 is connected to the inlet of the circulating tank 2. The brine circulating pump 3 drives the ammonium sulfate wastewater to circulate between the salt chamber 1027 and the brine circulating tank 2 to ensure ion migration efficiency. The flow direction of the ammonium sulfate wastewater is: brine circulating tank 2 → brine circulating pump 3 → inlet of salt chamber 1027 → treatment in salt chamber 1027 → outlet of salt chamber 1027 → return to brine circulating tank 2, forming a closed loop. The outlet of the alkali circulating tank 4 is connected to the inlet of the alkali chamber 1028 via the alkali circulating pump 5, and the outlet of the alkali chamber 1028 is connected to the inlet of the alkali circulating tank 4. The alkali circulating tank 4 stores dilute ammonia water (initially pure water), which is circulated to the alkali chamber 1028 by the alkali circulating pump 5 for gradual enrichment. To the target concentration (e.g., 6%); the alkali circulation pump 5 maintains fluid circulation between the alkali chamber 1028 and the alkali circulation water tank 4, promoting... and The reaction proceeds fully; the alkali solution flows as follows: alkali circulation tank 4 → alkali circulation pump 5 → inlet of alkali chamber 1028 → internal treatment in alkali chamber 1028 → outlet of alkali chamber 1028 → back to alkali circulation tank 4, forming a closed loop. The outlet of acid circulation tank 6 is connected to the inlet of acid chamber 1026 via acid circulation pump 7, and the outlet of acid chamber 1026 is connected to the inlet of acid circulation tank 6. Acid circulation tank 6 stores dilute sulfuric acid (initially pure water), which is circulated to acid chamber 1026 via acid circulation pump 7, gradually enriching the solution. To the target concentration (e.g., 6%); acid circulation pump 7 maintains fluid circulation between acid chamber 1026 and acid circulation water tank 6, promoting and The reaction proceeds fully; the acid flows as follows: acid circulating water tank 6 → acid circulating pump 7 → inlet of acid chamber 1026 → internal treatment in acid chamber 1026 → outlet of acid chamber 1026 → back to acid circulating water tank 6, forming a closed loop. Electrolyte circulating water tank 8 stores neutral electrolyte (e.g., 0.3 mol / L). The electrode water is pumped into the anode chamber 1025 and cathode chamber 1029 respectively by the electrode water circulation pump 9 to maintain the electrode reaction environment and conduct electricity. The electrode water circulation pump 9 drives the electrode water to circulate between the anode chamber 1025 / cathode chamber 1029 and the electrode water circulation tank 8 to prevent pH imbalance and gas accumulation in the electrode chambers. The electrode water flow direction is: electrode water circulation tank 8 → electrode water circulation pump 9 → inlet of anode chamber 1025 and cathode chamber 1029 → treatment in anode chamber 1025 and cathode chamber 1029 → outlet of anode chamber 1025 and cathode chamber 1029 → electrode water circulation tank 8, forming a closed loop.

[0028] Furthermore, it also includes a control system, which can automatically adjust the operating current of the bipolar membrane electrodialysis equipment 1 based on parameters such as the conductivity of the brine and the temperature / pressure / liquid level of each concentration unit, to ensure stable and efficient operation of the system.

[0029] This application provides a high-concentration ammonium sulfate wastewater treatment system. An electrode water circulation pump 9 drives electrode water to circulate between the anode chamber 1025 / cathode chamber 1029 and the electrode water circulation tank 8. A brine circulation pump 3 drives ammonium sulfate wastewater to circulate between the brine chamber 1027 and the brine circulation tank 2. An alkali circulation pump 5 maintains fluid circulation between the alkali chamber 1028 and the alkali circulation tank 4, and an acid circulation pump 7 maintains fluid circulation between the acid chamber 1026 and the acid circulation tank 6. The acid chamber 1026 receives… Dissociated from the first bipolar membrane 1021 Combined generation Alkali chamber 1028 receiving Dissociation from the second bipolar membrane 1024 Combined generation Compared to traditional processes (such as incineration and evaporation) that rely on high temperatures and pressures and have high energy consumption, the bipolar membrane electrodialysis equipment 1 utilizes electric field force to directly drive ion migration and recombination, requiring only low-voltage direct current to effectively reduce energy consumption. Ammonium sulfate is converted into sulfuric acid and ammonia, both of which are high-value-added products, achieving near-zero discharge, effectively avoiding secondary pollution, and improving resource utilization. The bipolar membrane electrodialysis equipment 1 directly desalinates through electrochemical separation, is not limited by microbial activity, and can improve treatment efficiency.

[0030] Based on the above embodiments, this application embodiment also includes a dilute acid transfer pump 10, a first heat exchanger 11, a sulfuric acid distillation column 12, a concentrated acid transfer pump 13, and a high-concentration sulfuric acid tank 14. The dilute acid transfer pump 10 is connected to the acid circulating water tank 6 and the first inlet of the first heat exchanger 11, respectively. The first outlet of the first heat exchanger 11 is connected to the inlet of the sulfuric acid distillation column 12. The outlet of the sulfuric acid distillation column 12 is connected to the second inlet of the first heat exchanger 11 through the concentrated acid transfer pump 13. The second outlet of the first heat exchanger 11 is connected to the high-concentration sulfuric acid tank 14.

[0031] When the ammonium sulfate concentration in salt chamber 1027 drops to 0.5 wt% and the acid concentration in acid circulation tank 6 stabilizes (e.g., 6%), dilute sulfuric acid is pumped by dilute acid transfer pump 10 into the first heat exchanger 11 for preheating, then enters the sulfuric acid distillation column 12. High-concentration sulfuric acid (greater than 6%) is produced at the bottom of the sulfuric acid distillation column 12, and is returned to the first heat exchanger 11 for cooling via concentrated acid transfer pump 13, before being stored in the high-concentration sulfuric acid tank 14. The first heat exchanger 11 has a dual heat exchange function: preheating the dilute acid using the residual heat of the high-temperature concentrated sulfuric acid; and cooling the concentrated acid by cooling the concentrated sulfuric acid output from the distillation column for storage in the high-concentration sulfuric acid tank 14. The sulfuric acid distillation column 12 concentrates the dilute sulfuric acid, separating water vapor at the top and outputting concentrated sulfuric acid at the bottom. The concentrated sulfuric acid stored in the high-concentration sulfuric acid tank 14 can be directly used in industrial production, reducing the company's procurement costs for external acid chemicals.

[0032] Based on the above embodiments, this application embodiment also includes a dilute alkali transfer pump 15, a second heat exchanger 16, an ammonia distillation column 17, and a high-concentration ammonia water tank 18. The dilute alkali transfer pump 15 is connected to the alkali circulation water tank 4 and the first inlet of the second heat exchanger 16. The first outlet of the second heat exchanger 16 is connected to the inlet of the ammonia distillation column 17. The top outlet of the ammonia distillation column 17 is connected to the second inlet of the second heat exchanger 16. The second outlet of the second heat exchanger 16 is connected to the high-concentration ammonia water tank 18.

[0033] When the ammonium sulfate concentration in salt chamber 1027 drops to 0.5 wt% and the alkali concentration in alkali circulating water tank 4 stabilizes (e.g., 6%), dilute ammonia water is pumped into the second heat exchanger 16 for preheating via dilute alkali transfer pump 15, and then enters the ammonia water distillation column 17. Concentrated ammonia water (greater than 6%) is produced at the top of the ammonia water distillation column 17, returning to the second heat exchanger 16 for cooling, and then stored in the high-concentration ammonia water tank 18. The second heat exchanger 16 has dual heat exchange functions: a preheating function, utilizing the residual heat of the high-temperature ammonia water vapor at the top of the ammonia water distillation column 17 to preheat the dilute ammonia water to near its bubble point, reducing distillation energy consumption; and a condensation function, cooling the high-concentration ammonia water vapor produced at the top of the column for storage in the high-concentration ammonia water tank 18. The ammonia water distillation column 17 distills dilute ammonia water under reduced pressure or atmospheric pressure conditions, with water discharged from the bottom of the column, and high-concentration ammonia water obtained at the top. Concentrated ammonia solution is stored in a high-concentration ammonia solution tank 18 and can be directly applied to industrial production processes, reducing the cost of purchasing external alkali chemicals for enterprises.

[0034] Based on the above embodiments, the system also includes a reverse osmosis feed water booster pump 19 and a security filter 20, with the reverse osmosis feed water booster pump 19 connected to the brine circulation tank 2 and the security filter 20, respectively.

[0035] When the ammonium sulfate concentration in salt chamber 1027 drops to 0.5 wt% and the acid / alkali concentration tends to stabilize, the brine discharged from salt chamber 1027 (with ammonium sulfate concentration reduced to approximately 0.5 wt%) is drawn out from brine circulation tank 2 and pressurized to meet the feed water pressure requirements of the subsequent reverse osmosis membrane unit. The security filter 20 removes any suspended solids or colloids that may remain in the brine and also protects the subsequent reverse osmosis feed water high-pressure pump 21 and the reverse osmosis (RO) membrane unit from mechanical blockage and scratches, thus improving system reliability.

[0036] Based on the above embodiments, this application embodiment also includes a reverse osmosis feed water high-pressure pump 21, an RO membrane device 22, and an RO product water tank 23. The reverse osmosis feed water high-pressure pump 21 is connected to the security filter 20 and the RO membrane device 22 respectively. The RO product water tank 23 is connected to the product water outlet of the RO membrane device 22, and the concentrate outlet of the RO membrane device 22 is connected to the brine circulating water tank 2.

[0037] The reverse osmosis feed high-pressure pump 21 further pressurizes the brine that has passed through the security filter 20 to the operating pressure required for reverse osmosis, overcoming osmotic pressure and driving water to preferentially permeate through the RO membrane. The RO membrane unit 22 utilizes the selective permeability of the semi-permeable membrane to separate the brine into two streams: permeate (permeate), which can be directly reused or discharged; and concentrate (retentate), with its ammonium sulfate concentration increased again, which flows back to the brine circulation tank 2 for further treatment in the bipolar membrane electrodialysis unit 1. The RO permeate tank 23 stores the reverse osmosis permeate, serving as process water for the system or as a water source for other reuse points within the plant, ensuring improved overall water recovery rate and achieving near-zero discharge.

[0038] Based on the above embodiments, this application embodiment also includes an online reverse osmosis feed water conductivity meter 24 and an online reverse osmosis product water conductivity meter 25. The online reverse osmosis feed water conductivity meter 24 is installed on the pipeline connecting the brine circulating water tank 2 and the security filter 20, and the online reverse osmosis product water conductivity meter 25 is installed on the pipeline connecting the RO membrane device 22 and the RO product water tank 23.

[0039] An online reverse osmosis feed water conductivity meter 24 is installed on the pipeline between the brine circulation tank 2 and the security filter 20. It monitors the conductivity of the brine entering the RO membrane unit 22 in real time, indirectly reflecting changes in ammonium sulfate concentration. When the conductivity is lower than a set threshold (corresponding to below 0.5 wt%), it can adjust the operating current or brine circulation rate of the bipolar membrane electrodialysis equipment 1 to ensure stable feed water quality for the RO membrane unit 22 and prevent membrane scaling or excessive concentration. An online reverse osmosis permeate conductivity meter 25 is installed on the pipeline between the RO membrane unit 22 and the RO permeate tank 23. It continuously monitors the permeate conductivity to determine the desalination performance of the RO membrane in real time. If the permeate conductivity rises abnormally, it immediately triggers an alarm or automatically shuts down, indicating membrane fouling, damage, or operational abnormality, ensuring the safety of the recycled water quality.

[0040] Based on the above embodiments, this application embodiment also includes a reverse osmosis permeate flow meter 26 and a reverse osmosis concentrate flow meter 27. The reverse osmosis permeate flow meter 26 is installed on the pipeline connecting the RO membrane device 22 and the RO permeate tank 23, and the reverse osmosis concentrate flow meter 27 is installed on the pipeline connecting the RO membrane device 22 and the brine circulating water tank 2.

[0041] The reverse osmosis permeate flow meter 26 is installed in the pipeline between the RO membrane unit 22 and the RO permeate tank 23; it records the instantaneous and cumulative flow of the permeate from the RO membrane unit 22 in real time, which can be used to determine the performance trend of the RO membrane (a decrease in flow indicates membrane fouling or scaling). The reverse osmosis concentrate flow meter 27 is installed in the pipeline between the RO membrane unit 22 and the brine circulating water tank 2; it can be used to monitor the concentrate flow in real time. When the concentrate flow abnormally decreases (e.g., membrane fouling) or increases (e.g., membrane rupture), it triggers an alarm and shuts down the system to protect the safety of the system.

[0042] Based on the above embodiments, the RO permeate tank 23 is also connected to the alkali circulating water tank 4 and the acid circulating water tank 6. The RO permeate tank 23 can also be used to replenish the pure water required by the acid chamber 1026 and the alkali chamber 1028, realizing the full utilization of RO permeate within the system, further reducing operating costs and improving the overall water recovery rate.

[0043] In summary, during the desalinated water resource utilization stage: the desalinated water discharged from the salt chamber 1027 is pressurized and transported to the security filter 20 via reverse osmosis feed water. The filtrate enters the RO membrane unit 22 through the reverse osmosis feed water high-pressure pump 21. The permeate from the RO membrane unit 22 is collected in the RO permeate tank 23 and reused for makeup water in the alkaline circulating water tank 4 and the acid circulating water tank 6, thereby improving the system recovery rate.

[0044] Based on the above embodiments, this application embodiment also includes a pretreatment device connected to the brine circulating water tank 2. The pretreatment device is used to pretreat the ammonium sulfate wastewater. The specific pretreatment method is not specifically limited in this application embodiment. Before the ammonium sulfate wastewater enters the brine circulating water tank 2, a series of pretreatment processes remove suspended solids, colloids, some organic matter, and heavy metals, preventing fouling and scaling of the ion exchange membrane of the bipolar membrane electrodialysis equipment 1 and ensuring long-term stable operation of the system.

[0045] Based on the above embodiments, Figure 2 This is a schematic diagram of a bipolar membrane electrodialysis device 1 provided in an embodiment of this application, as shown below. Figure 2As shown, there are multiple functional chambers 102. The acid chamber 1026 of one functional chamber 102 and the alkali chamber 1028 of another adjacent functional chamber 102 share a bipolar membrane, forming a repeating membrane stack unit structure. Multiple functional chambers 102 share a common electric field, reducing resistance and energy consumption; multiple functional chambers 102 can be connected in series as needed to increase throughput and acid / alkali yield.

[0046] This application utilizes a novel combined process—with bipolar membrane electrodialysis (BMED) as the core, coupled with distillation concentration and brine reuse—to achieve efficient resource utilization of ammonium sulfate wastewater. This molecular-level transformation from salt to acid and alkali enables the efficient and clean conversion and recovery of salts (ammonium sulfate) from ammonium sulfate wastewater into high-value-added acid and alkali products (sulfuric acid and ammonia). This not only achieves value-added treatment of high-concentration saline wastewater, but also significantly outperforms traditional technologies such as high-temperature incineration and deep well injection in terms of resource recovery rate, energy consumption, and environmental benefits. Furthermore, it provides a new technological pathway for near-zero discharge of industrial wastewater. Details are as follows:

[0047] By utilizing bipolar membrane electrodialysis technology, the molecular transformation from salt to acid and alkali is achieved, solving the problem of concentrated brine disposal. Electrical energy drives molecular recombination, replacing thermal energy consumption and effectively reducing energy consumption. Further distillation produces high-concentration, high-purity acid and alkali solutions, which can be directly applied in industrial production, reducing the cost of purchasing external acid and alkali chemicals for enterprises. The desalinated brine is connected to a reverse osmosis membrane system, further realizing a triple cycle of water, salt, and product, achieving near-zero wastewater discharge and reuse, effectively avoiding secondary pollution risks. Through the output of high-value acid and alkali products and internal resource recycling, a win-win situation for both economic and environmental benefits is achieved, providing a new technological path for the resource utilization of industrial wastewater.

[0048] The distillation product self-preheating and self-cooling loop works as follows: Sulfuric acid distillation column outlet → hot side of heat exchanger → preheating of dilute acid feed → return to cold side to cool the product. Ammonia distillation column outlet → hot side of heat exchanger → preheating of dilute alkali feed → return to cold side to cool the product. Utilizing the waste heat of the product to preheat the feed reduces distillation energy consumption, eliminates the need for external cooling devices, and lowers equipment costs.

[0049] The pretreated wastewater is pumped into the bipolar membrane electrodialysis unit. Operating at a constant current density, the ammonium sulfate concentration at the salt chamber inlet is approximately 15%, and the dilute brine concentration at the outlet drops to below approximately 0.5%. The acid chamber produces approximately 6% dilute sulfuric acid, and the alkali chamber produces approximately 6% dilute ammonia. The operating temperature is controlled at around 40℃.

[0050] The control system automatically adjusts the operating current of the bipolar membrane electrodialysis equipment based on parameters such as the conductivity of the brine and the temperature, pressure, and liquid level of each concentration unit to ensure stable and efficient system operation.

[0051] The above provides a detailed description of a high-concentration ammonium sulfate wastewater treatment system provided in this application. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0052] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A high-concentration ammonium sulfate wastewater treatment system, characterized in that, include: Bipolar membrane electrodialysis equipment (1), brine circulating water tank storing ammonium sulfate wastewater (2), brine circulating pump (3), alkali circulating water tank (4), alkali circulating pump (5), acid circulating water tank (6), acid circulating pump (7), polar water circulating water tank (8) and polar water circulating pump (9). The bipolar membrane electrodialysis device (1) includes an anode plate (101), a functional chamber (102), and a cathode plate (103). The functional chamber (102) includes a first bipolar membrane (1021), an anion exchange membrane (1022), a cation exchange membrane (1023), and a second bipolar membrane (1024) spaced apart along the anode plate (101) to the cathode plate (103). The anode chamber (1025) is located between the anode plate (101) and the first bipolar membrane (1021). The acid chamber (1026) is located between the first bipolar membrane (1021) and the anion exchange membrane (1022). The salt chamber (1027) is located between the anion exchange membrane (1022) and the cation exchange membrane (1023). The cation exchange membrane (1023) and the second bipolar membrane (1024) form an alkali chamber (1028), and the second bipolar membrane (1024) and the cathode plate (103) form a cathode chamber (1029). The brine circulation tank (2) is connected to the inlet and outlet of the brine chamber (1027) via the brine circulation pump (3). The alkali circulation tank (4) is connected to the inlet and outlet of the alkali chamber (1028) via the alkali circulation pump (5). The acid circulation tank (6) is connected to the inlet and outlet of the acid chamber (1026) via the acid circulation pump (7). The polar water circulation tank (8) is connected to the inlet and outlet of the anode chamber (1025) and the inlet and outlet of the cathode chamber (1029) via the polar water circulation pump (9).

2. The high-concentration ammonium sulfate wastewater treatment system according to claim 1, characterized in that, It also includes a dilute acid transfer pump (10), a first heat exchanger (11), a sulfuric acid distillation column (12), a concentrated acid transfer pump (13), and a high-concentration sulfuric acid tank (14). The dilute acid transfer pump (10) is connected to the acid circulating water tank (6) and the first inlet of the first heat exchanger (11). The first outlet of the first heat exchanger (11) is connected to the inlet of the sulfuric acid distillation column (12). The outlet of the sulfuric acid distillation column (12) is connected to the second inlet of the first heat exchanger (11) through the concentrated acid transfer pump (13). The second outlet of the first heat exchanger (11) is connected to the high-concentration sulfuric acid tank (14).

3. The high-concentration ammonium sulfate wastewater treatment system according to claim 1, characterized in that, It also includes a dilute alkali transfer pump (15), a second heat exchanger (16), an ammonia distillation column (17), and a high-concentration ammonia water tank (18). The dilute alkali transfer pump (15) is connected to the alkali circulation water tank (4) and the first inlet of the second heat exchanger (16). The first outlet of the second heat exchanger (16) is connected to the inlet of the ammonia distillation column (17). The top outlet of the ammonia distillation column (17) is connected to the second inlet of the second heat exchanger (16). The second outlet of the second heat exchanger (16) is connected to the high-concentration ammonia water tank (18).

4. The high-concentration ammonium sulfate wastewater treatment system according to claim 1, characterized in that, It also includes a reverse osmosis feed water booster pump (19) and a security filter (20), wherein the reverse osmosis feed water booster pump (19) is connected to the brine circulating water tank (2) and the security filter (20) respectively.

5. The high-concentration ammonium sulfate wastewater treatment system according to claim 4, characterized in that, It also includes a reverse osmosis feed water high-pressure pump (21), an RO membrane device (22) and an RO product water tank (23). The reverse osmosis feed water high-pressure pump (21) is connected to the security filter (20) and the RO membrane device (22) respectively. The RO product water tank (23) is connected to the product water outlet of the RO membrane device (22), and the concentrate outlet of the RO membrane device (22) is connected to the brine circulating water tank (2).

6. The high-concentration ammonium sulfate wastewater treatment system according to claim 5, characterized in that, It also includes an online reverse osmosis feed water conductivity meter (24) and an online reverse osmosis product water conductivity meter (25). The online reverse osmosis feed water conductivity meter (24) is installed on the pipeline connecting the brine circulating water tank (2) and the security filter (20), and the online reverse osmosis product water conductivity meter (25) is installed on the pipeline connecting the RO membrane device (22) and the RO product water tank (23).

7. The high-concentration ammonium sulfate wastewater treatment system according to claim 6, characterized in that, It also includes a reverse osmosis permeate flow meter (26) and a reverse osmosis concentrate flow meter (27). The reverse osmosis permeate flow meter (26) is installed on the pipeline connecting the RO membrane device (22) and the RO permeate tank (23). The reverse osmosis concentrate flow meter (27) is installed on the pipeline connecting the RO membrane device (22) and the brine circulating water tank (2).

8. The high-concentration ammonium sulfate wastewater treatment system according to claim 5, characterized in that, The RO product water tank (23) is also connected to the alkaline circulating water tank (4) and the acid circulating water tank (6).

9. The high-concentration ammonium sulfate wastewater treatment system according to claim 1, characterized in that, It also includes a pretreatment device, which is connected to the brine circulating water tank (2).

10. The high-concentration ammonium sulfate wastewater treatment system according to any one of claims 1 to 9, characterized in that, There are multiple functional chambers (102), and the acid chamber (1026) of one functional chamber (102) and the alkali chamber (1028) of the other functional chamber (102) share a bipolar membrane.

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