A method and apparatus for treating heparin sodium production wastewater

Abstract

This application discloses a method and equipment for treating wastewater from heparin sodium production. Belonging to the field of wastewater treatment technology, the method comprises the following steps: first, adjusting the pH of the wastewater to 3.5–5.0 and heating it, then using a coagulant to coagulate and recover proteins, obtaining a first filtrate; next, passing the wastewater through an electrolytic cell with titanium-based electrodes to break down the gel chains, obtaining a second filtrate; then, using a nanofiltration membrane with a molecular weight cutoff of 150–500 Da for precise salt separation, obtaining sodium chloride permeate and organic concentrate; finally, using reverse osmosis for concentration to obtain high-purity sodium chloride concentrate, which is then reused in heparin sodium production. This invention organically couples four steps: acid-thermal coagulation to recover proteins, electro-oxidation to pre-remove membrane fouling factors, special nanofiltration for selective salt separation, and reverse osmosis concentration. For the first time, it achieves highly efficient dual recovery of proteins and salts from wastewater in the same process, completely solving the common industry problems of severe membrane fouling and difficult salt separation in high-salt, high-protein wastewater. It has low operating costs and truly achieves near-zero emissions and resource recycling.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method and equipment for treating wastewater from heparin sodium production. Background Technology

[0002] Heparin sodium is an important anticoagulant drug. The mainstream production process includes enzymatic hydrolysis / saltation, ion exchange resin adsorption, sodium chloride solution elution, and ethanol precipitation. During the resin adsorption process, a large amount of residual liquid after heparin adsorption is discharged, which is heparin sodium production wastewater. This wastewater has the following significant characteristics: sodium chloride concentration is as high as 2%–5%, protein and polypeptide content is 1%–3%, chemical oxygen demand (COD) is typically 20,000–50,000 mg / L, and it also contains small amounts of fat, pigments, sulfates, and residual heparin. The wastewater is dark brown, highly viscous, and has a strong, fishy odor.

[0003] Currently, the main methods for treating wastewater from heparin sodium production include: Multi-effect evaporation or MVR evaporation crystallization: extremely high energy consumption, and a large amount of protein in the wastewater cokes and foams during the evaporation process, which seriously affects the heat transfer efficiency; the resulting mixed salt contains a large amount of organic matter, has low purity, and is costly to treat as hazardous waste.

[0004] Biochemical methods: High salinity can severely inhibit microbial activity. Traditional activated sludge processes require large amounts of fresh water to dilute the sludge by 5-10 times, which wastes water resources and requires a large area. Although protein anaerobic fermentation can produce methane, high salt and sulfate levels can easily lead to system collapse and poor operational stability.

[0005] Direct membrane filtration: The abundant soluble proteins and colloids in wastewater rapidly foul ultrafiltration or nanofiltration membranes, causing extremely rapid flux decay, frequent chemical cleaning, and difficulty in continuous operation.

[0006] It is evident that existing technologies are either energy-intensive and low-output, or simply cannot operate stably, and none have achieved the resource recovery of valuable proteins and high-purity sodium chloride from wastewater. Therefore, there is an urgent need for a new method that can simultaneously recover proteins and salts, achieve near-zero emissions, and has low operating costs. Summary of the Invention

[0007] The purpose of this invention is to provide a method and equipment for treating wastewater from heparin sodium production, in order to solve the problems mentioned in the background art regarding the prior art wastewater recycling, which is either high in energy consumption and low in output, or simply cannot operate stably, and neither of them has achieved the resource recovery of valuable proteins and high-purity sodium chloride in the wastewater.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for treating wastewater from heparin sodium production includes the following steps: S1: Protein denaturation and coagulation: Adjust the pH of the heparin sodium production wastewater to 3.5-5.0, heat it to 60-90℃, maintain the temperature and stir for 10-60 minutes, and add a coagulant to denature and coagulate the proteins in the water to form flocs. Then, perform solid-liquid separation to obtain protein precipitate and the first filtrate.

[0009] S2: Electrochemical oxidation to break down gels and chains: The first filtrate is fed into an electrolytic cell, using titanium-coated electrodes as the anode and cathode, at a current density of 10–50 mA / cm². 2 Electrolysis is performed under certain conditions, using the strong oxidizing free radicals generated at the anode to oxidize and degrade the remaining soluble proteins, peptides, and chromogenic organic matter. At the same time, the colloidal charge characteristics are changed to destabilize the colloidal substance, resulting in the second filtrate.

[0010] S3: Special Nanofiltration for Precise Salt Separation: The pH of the second filtrate is adjusted to 6.0–8.0, and then separated by a nanofiltration membrane module with a molecular weight cutoff of 150–500 Daltons. Under an operating pressure of 0.5–2.0 MPa, a permeate mainly containing sodium chloride and a concentrate containing macromolecular organics and polyvalent salts are obtained.

[0011] S4: Reverse osmosis concentration and salt recovery: The permeate obtained in step S3 is concentrated through a reverse osmosis membrane to obtain sodium chloride concentrate and reusable permeate; the sodium chloride concentrate has a sodium chloride concentration of 80-120 g / L and can be directly reused in the ion exchange elution process or salt hydrolysis process in the production of heparin sodium.

[0012] The method of this invention first denatures and precipitates most of the proteins under precise acid-heat conditions, thereby significantly reducing COD and obtaining high-value-added protein feed ingredients. Next, electrochemical oxidation is used to precisely break down the colloidal chains of residual soluble proteins and peptides, further reducing the molecular weight of organic matter in the water and destroying the colloidal protective layer. This creates crucial conditions for the subsequent long-term anti-fouling operation of the nanofiltration membrane under extremely high salinity. Then, using a special nanofiltration membrane with precise molecular weight cutoff, high permeability to sodium chloride and high rejection rates for residual organic matter and sulfates are achieved in single-stage separation, resulting in high-purity sodium chloride brine. Finally, reverse osmosis is used to concentrate this pure brine to a reuse concentration, achieving a closed-loop circulation of water and salt within the plant. The entire method organically couples "protein recovery - membrane fouling pre-control - precise salt separation - salt concentration," achieving, for the first time in the field of heparin sodium wastewater treatment, the resource recovery of all components.

[0013] Preferably, in step S1, the coagulant is nonionic polyacrylamide, and the dosage is 1-5 mg per liter of wastewater. Nonionic coagulants are less susceptible to charge shielding in high-salt environments, effectively trapping and sweeping denatured protein particles, resulting in dense sediment and good dehydration.

[0014] Preferably, in step S2, the coating of the titanium-based coated electrode is a ruthenium-iridium oxide coating, and the distance between the anode and cathode plates is 1–3 cm. This electrode has a high oxygen evolution potential, high efficiency in generating hydroxyl radicals, and excellent resistance to chloride ion corrosion.

[0015] Preferably, in step S3, the nanofiltration membrane is a polyamide composite nanofiltration membrane, which has a magnesium sulfate rejection rate of not less than 95% and a sodium chloride rejection rate of not more than 15%. This characteristic of "high salt throughput and high organic rejection" is the core of achieving precise salt separation.

[0016] Preferably, in step S4, the reverse osmosis membrane is a seawater desalination reverse osmosis membrane, and the operating pressure is 3.0–5.5 MPa. The recycled water generated in step S4 has a conductivity of less than 150 μS / cm and can be reused in the cleaning section of production or as boiler feedwater.

[0017] Preferably, the method of the present invention further includes step S5, deep treatment of the concentrate: introducing the concentrate obtained in step S3 into an anaerobic digestion reactor, or subjecting it to wet oxidation treatment, to further mineralize the organic matter. When the concentrate is small in quantity but concentrated, it can also be directly spray-dried or disposed of in compliance with regulations after being rendered harmless.

[0018] Another object of the present invention is to provide an apparatus for treating wastewater from heparin sodium production, comprising the following components connected sequentially along the water flow direction: A protein coagulation separation unit includes an acidification coagulation tank with a heating jacket and a stirrer, and a solid-liquid separator connected to the outlet of the acidification coagulation tank; used to perform step S1; An electrochemical oxidation unit includes an electrolytic cell and a titanium-based coated electrode assembly installed therein. The inlet of the electrolytic cell is connected to the liquid phase outlet of the solid-liquid separator; used to perform step S2. A nanofiltration separation unit includes a pH adjustment tank, a security filter, and a nanofiltration membrane assembly connected in sequence. The inlet of the nanofiltration membrane assembly is connected to the outlet of the electrochemical oxidation unit; used to perform step S3. A reverse osmosis concentration unit includes a high-pressure pump and a reverse osmosis membrane module, the inlet of which is connected to the permeate outlet of a nanofiltration membrane module; used to perform step S4; And a brine recycling tank connected to the concentrate outlet of the reverse osmosis membrane module.

[0019] When the equipment operates in tandem, the wastewater completes the solid-state recovery of proteins at the first end, and the liquid phase is completely "modified" in the electrochemical unit, no longer posing a pollution threat to the nanofiltration membrane. The two-stage membrane process of nanofiltration and reverse osmosis can obtain high-quality brine through physical separation only. The entire process is closed, continuous, and highly automated.

[0020] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a comprehensive resource recovery route for heparin sodium wastewater, encompassing "acid-thermal coagulation-electro-nanofiltration-reverse osmosis." This is not a simple combination, but a tightly logical chain method based on the targeted removal mechanisms of each unit for pollutants. Acid-thermal coagulation specifically removes large protein molecules accounting for over 50% of COD; electro-oxidation precisely targets residual dissolved organic matter and eliminates subsequent membrane fouling factors; nanofiltration selectively separates pure brine and organic matter; and reverse osmosis completes the final concentration. Leveraging the unique "pre-decontamination" effect of electrochemical oxidation, it solves the industry problem of inevitable fouling during membrane concentration of high-salt, high-protein wastewater, enabling nanofiltration membranes to operate stably for extended periods under extremely demanding water conditions, and extending cleaning cycles several times over. It achieves dual recovery of protein and high-purity sodium chloride. The protein has high purity and can be used as feed raw material; the concentrated sodium chloride has a purity greater than 97% and can be directly reused in production processes, turning waste into treasure. Its economic and environmental benefits far surpass any evaporation or simple biochemical process.

[0021] Other features and advantages of the present invention will be disclosed in detail in the following detailed description and accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a device diagram of the present invention; The figures are labeled as follows: 1. Protein coagulation separation unit; 101. Acidification coagulation tank; 102. Solid-liquid separator; 2. Electrochemical oxidation unit; 201. Electrolytic cell; 202. Titanium-coated electrode assembly; 3. Nanofiltration separation unit; 301. pH adjustment tank; 302. Security filter; 303. Nanofiltration membrane module; 4. Reverse osmosis concentration unit; 401. High-pressure pump; 402. Reverse osmosis membrane module; 5. Brine reuse storage tank. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] A method for treating wastewater from heparin sodium production involves denaturing and coagulating the wastewater to precipitate and recover most of the protein, resulting in protein precipitate and a first filtrate. The first filtrate is then subjected to electrochemical oxidation to break down the colloidal chains, degrading residual soluble proteins and peptides, and simultaneously altering the colloidal charge properties to destabilize them, yielding a second filtrate. This second filtrate is then precisely separated using a specialized nanofiltration membrane to obtain a permeate primarily containing sodium chloride and a concentrate retaining large organic molecules and polyvalent salts. The permeate is further concentrated using a reverse osmosis membrane to obtain concentrated sodium chloride and reusable permeate. The concentrated sodium chloride is directly reused in the ion exchange elution or salt hydrolysis processes during heparin sodium production.

[0025] In an improved embodiment, heparin sodium production wastewater is first pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. The heating jacket of the acidification and coagulation tank is used to heat the wastewater inside the tank, and the stirrer is used to ensure uniform heating of the wastewater during the acidification and heating process and to promote sufficient contact between the coagulant and protein flocs. Under stirring conditions, acid is added to the wastewater to adjust the pH to 3.5–5.0, and the temperature is heated to 60–90°C through the heating jacket. This temperature is maintained for 10–60 minutes under stirring, and nonionic polyacrylamide is added to the tank as a coagulant at a dosage of 1–5 mg per liter of wastewater, causing the proteins in the water to denature and coagulate to form flocs under acidic and hot conditions. After the stirring is completed, the mixture in the acidification and coagulation tank is sent to a solid-liquid separator for solid-liquid separation. The solid-liquid separator can be a horizontal screw centrifuge or a plate and frame filter press. It utilizes centrifugal force or filtration pressure to continuously separate protein flocs from the liquid phase. The liquid phase outlet of the solid-liquid separator discharges the first filtrate, and the solid phase outlet discharges the protein precipitate. After drying, the protein precipitate can be sold as a high-protein feed ingredient, achieving the resource recovery of major organic matter in wastewater. This step achieves a COD removal rate of 50%–55% and a protein removal rate exceeding 85%. The color of the first filtrate changes significantly from dark brown, and its viscosity decreases markedly.

[0026] In the electrochemical oxidation unit, a titanium-based coated electrode assembly is installed in the electrolytic cell. The coating of the titanium-based coated electrode is a ruthenium-iridium oxide coating, and the distance between the anode and cathode plates is 1–3 cm. This electrode has a high oxygen evolution potential, high efficiency in generating hydroxyl radicals, and excellent resistance to chloride ion corrosion. The first filtrate discharged from the solid-liquid separator enters the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. A DC power supply is then connected, and the current density is 10–50 mA / cm². 2Electrolysis is performed under specific conditions. During electrolysis, strong oxidizing free radicals are generated on the anode surface, oxidizing and degrading the residual soluble proteins, peptides, and chromogenic organic matter in the first filtrate. Simultaneously, the colloidal charge characteristics are altered, causing instability and a decrease in the colloidal zeta potential. This results in the loss of the electrostatic repulsion protective layer, thus eliminating the ability to subsequently deposit a dense fouling layer on the nanofiltration membrane surface, yielding the second filtrate. The second filtrate, after electrochemical oxidation treatment, shows a significant reduction in the molecular weight of organic matter, and the colloidal protective layer is destroyed, resulting in a substantial decrease in the fouling tendency of the feed solution on subsequent nanofiltration membrane modules.

[0027] In the nanofiltration separation unit, the second filtrate discharged from the electrochemical oxidation unit enters a pH adjustment tank. Acid or alkali is added to the second filtrate in the pH adjustment tank to adjust its pH to 6.0–8.0. The purpose of pH adjustment is to achieve an optimal match between the dissociation state of organic molecules in the second filtrate and the charge characteristics of the nanofiltration membrane surface, ensuring sufficient retention of organic matter and polyvalent salts while maintaining high permeability for sodium chloride. After pH adjustment, the feed solution passes through a security filter equipped with a 5-micron precision polypropylene melt-blown filter element to trap any trace suspended particles that may be present in the feed solution, preventing these particles from scratching or clogging the membrane surface in the subsequent nanofiltration membrane module. The outlet of the security filter connects to the inlet of the nanofiltration membrane module. The nanofiltration membrane module is filled with a polyamide composite nanofiltration membrane with a molecular weight cutoff of 150–500 Daltons. This membrane exhibits a rejection rate of at least 95% for magnesium sulfate and at least 15% for sodium chloride, demonstrating typical high salt throughput and high rejection rates for polyvalent salts and organic matter. Separation is performed under operating pressures of 0.5–2.0 MPa. Water and sodium chloride molecules in the feed solution permeate through the nanofiltration membrane under pressure, becoming the permeate, which is discharged from the permeate outlet of the nanofiltration membrane module. Residual organic matter with molecular weights greater than the cutoff, polyvalent ions such as sulfate, and some divalent cations in the feed solution are retained by the membrane, forming a concentrate, which is discharged from the concentrate outlet of the nanofiltration membrane module. The permeate of the nanofiltration membrane module is a high-purity sodium chloride solution, with a sodium chloride recovery rate exceeding 92%. The permeate is colorless and transparent, with significantly reduced COD and extremely low sulfate content.

[0028] In the reverse osmosis concentration unit, the permeate discharged from the nanofiltration membrane module is pressurized to an operating pressure of 3.0–5.5 MPa by a high-pressure pump before entering the reverse osmosis membrane module. The membrane packed in the reverse osmosis membrane module is a seawater desalination reverse osmosis membrane, which has a dense desalination layer and a high sodium chloride rejection rate. Under high pressure, water molecules in the permeate pass through the reverse osmosis membrane to become product water, which is discharged from the product water outlet of the reverse osmosis membrane module. The product water has a conductivity of less than 150 μS / cm and can be reused in the cleaning section of the production process or as boiler feedwater. Sodium chloride is retained on the concentrate side by the reverse osmosis membrane. As water continues to permeate, the sodium chloride concentration on the concentrate side gradually increases, eventually yielding sodium chloride concentrate with a concentration of 80–120 g / L, which is discharged from the concentrate outlet of the reverse osmosis membrane module and temporarily stored in a brine recycling storage tank connected to the concentrate outlet of the reverse osmosis membrane module. The sodium chloride concentrate in the brine recycling tank is directly reused in the ion exchange elution process or salt hydrolysis process in the production of heparin sodium, realizing the internal recycling of salt resources.

[0029] In one embodiment of the invention, the concentrate discharged from the nanofiltration membrane module's concentrate outlet is introduced into an anaerobic digester for anaerobic biological treatment. Under anaerobic conditions, anaerobic microorganisms convert organic matter into biogas, achieving energy recovery from organic matter. Alternatively, the concentrate can be subjected to wet oxidation treatment, utilizing oxygen under high temperature and high pressure conditions to oxidize and mineralize the organic matter in the concentrate. When the volume of concentrate is small, it can also be directly spray-dried or disposed of in accordance with regulations.

[0030] Based on the above method, this invention provides an apparatus for treating wastewater from heparin sodium production, comprising a protein coagulation separation unit, an electrochemical oxidation unit, a nanofiltration separation unit, and a reverse osmosis concentration unit connected sequentially along the water flow direction, and a brine reuse storage tank connected to the concentrate outlet of the reverse osmosis membrane module. The protein coagulation separation unit includes an acidification coagulation tank with a heating jacket and a stirrer, and a solid-liquid separator connected to the outlet of the acidification coagulation tank. The electrochemical oxidation unit includes an electrolytic cell and a titanium-coated electrode assembly installed within the electrolytic cell; the inlet of the electrolytic cell is connected to the liquid phase outlet of the solid-liquid separator. The nanofiltration separation unit includes a pH adjustment tank, a security filter, and a nanofiltration membrane module connected sequentially; the inlet of the nanofiltration membrane module is connected to the outlet of the electrochemical oxidation unit. The reverse osmosis concentration unit includes a high-pressure pump and a reverse osmosis membrane module; the inlet of the reverse osmosis membrane module is connected to the permeate outlet of the nanofiltration membrane module. The brine reuse storage tank is connected to the concentrate outlet of the reverse osmosis membrane module.

[0031] In one embodiment, the solid-liquid separator is a horizontal screw centrifuge or a plate and frame filter press. The heating jacket of the acidification coagulation tank is used to heat the wastewater inside the tank, and the agitator is used to ensure uniform heating of the wastewater during the acidification heating process and to promote sufficient contact between the coagulant and protein flocs. The security filter is used to intercept trace suspended particulate matter that may be carried in the influent of the nanofiltration membrane module, protecting the safe operation of the nanofiltration membrane module.

[0032] The present invention will be further illustrated by specific embodiments below.

[0033] Example 1

[0034] The wastewater from heparin sodium production contains 3.2% sodium chloride, 38,500 mg / L COD, 2.1% total protein, 0.6% sulfate, and a pH of 6.8. 200 kg of wastewater was pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. Dilute sulfuric acid was added to adjust the pH to 4.0 under stirring. The tank was then heated to 75°C using the heating jacket and maintained at this temperature with stirring for 30 minutes. Non-ionic polyacrylamide was added to the tank at a dosage of 3 mg per liter of wastewater. After stirring, the mixture was sent to a solid-liquid separator for solid-liquid separation, yielding protein precipitate and a first filtrate. The first filtrate entered the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. The electrolytic cell was equipped with a titanium-based coated electrode assembly with a ruthenium-iridium oxide coating, with a plate spacing of 2 cm, and operated at a current density of 30 mA / cm². 2 Electrolysis was performed under the specified conditions to obtain a second filtrate. The second filtrate entered the pH adjustment tank of the nanofiltration separation unit, where the pH was adjusted to 7.0. After passing through a security filter, it entered the nanofiltration membrane module. The nanofiltration membrane module was filled with a polyamide composite nanofiltration membrane with a molecular weight cutoff of 300 Daltons. Separation was performed under an operating pressure of 1.2 MPa to obtain permeate and concentrate. The permeate entered the reverse osmosis concentration unit, was pressurized to an operating pressure of 4.0 MPa by a high-pressure pump, and then entered the seawater desalination reverse osmosis membrane module for concentration to obtain sodium chloride concentrate and recycled water. The sodium chloride concentrate had a sodium chloride concentration of 100 g / L and was transported to a brine recycling tank for reuse in the ion exchange elution process in heparin sodium production. The recycled water had a conductivity of 120 μS / cm and was reused in the production cleaning section. The experimental results under different conditions are as follows:

[0035] It can be seen that the protein removal effect is good in the pH range of 3.5 to 5.0, and the protein precipitation purity is the highest at pH 4.0.

[0036] Example 2

[0037] The wastewater from heparin sodium production contains 3.2% sodium chloride, 38,500 mg / L COD, 2.1% total protein, 0.6% sulfate, and a pH of 6.8. 200 kg of wastewater was pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. Dilute sulfuric acid was added to adjust the pH to 4.0 under stirring. The tank was then heated to 60°C, 75°C, and 90°C respectively, and maintained at this temperature with stirring for 30 minutes. Non-ionic polyacrylamide was added to the tank at a dosage of 3 mg / L of wastewater. After stirring, the mixture was sent to a solid-liquid separator for solid-liquid separation, yielding protein precipitate and a first filtrate. The first filtrate entered the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. The electrolytic cell was equipped with a titanium-based coated electrode assembly with a ruthenium-iridium oxide coating, with a plate spacing of 2 cm, and operated at a current density of 30 mA / cm². 2 Electrolysis was performed under the specified conditions to obtain a second filtrate. The second filtrate entered the pH adjustment tank of the nanofiltration separation unit, where the pH was adjusted to 7.0. After passing through a security filter, it entered the nanofiltration membrane module. The nanofiltration membrane module was filled with a polyamide composite nanofiltration membrane with a molecular weight cutoff of 300 Daltons. Separation was performed under an operating pressure of 1.2 MPa to obtain permeate and concentrate. The permeate entered the reverse osmosis concentration unit, was pressurized to an operating pressure of 4.0 MPa by a high-pressure pump, and then entered the seawater desalination reverse osmosis membrane module for concentration to obtain sodium chloride concentrate and recycled water. The experimental results under different conditions are as follows:

[0038] It can be seen that the temperature range of 60 to 90℃ has a good protein removal effect. Among them, the protein precipitation purity is the best at 75℃, and the COD and protein removal rates are the highest at 90℃, but the energy consumption increases.

[0039] Example 3

[0040] The wastewater from heparin sodium production contains 3.2% sodium chloride, 38,500 mg / L COD, 2.1% total protein, 0.6% sulfate, and a pH of 6.8. 200 kg of wastewater was pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. Dilute sulfuric acid was added to adjust the pH to 4.0 under stirring. The tank was then heated to 75°C using the heating jacket and maintained at this temperature with stirring for 30 minutes. Non-ionic polyacrylamide was added to the tank at a dosage of 3 mg per liter of wastewater. After stirring, the mixture was sent to a solid-liquid separator for solid-liquid separation, yielding protein precipitate and a first filtrate. The first filtrate entered the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. The electrolytic cell was equipped with titanium-based coated electrodes with ruthenium-iridium oxide coating, with electrode spacings of 1 cm, 2 cm, and 3 cm, and current densities of 10 mA / cm². 2 30mA / cm 2and 50mA / cm 2 Electrolysis was performed under the specified conditions to obtain a second filtrate. The second filtrate entered the pH adjustment tank of the nanofiltration separation unit, where the pH was adjusted to 7.0. After passing through a security filter, it entered the nanofiltration membrane module. The nanofiltration membrane module was filled with a polyamide composite nanofiltration membrane with a molecular weight cutoff of 300 Daltons. Separation was performed under an operating pressure of 1.2 MPa to obtain permeate and concentrate. The permeate entered the reverse osmosis concentration unit, was pressurized to an operating pressure of 4.0 MPa by a high-pressure pump, and then entered the seawater desalination reverse osmosis membrane module for concentration to obtain sodium chloride concentrate and recycled water. The experimental results under different conditions are as follows:

[0041] It can be seen that the current density is between 10 and 50 mA / cm². 2 It can effectively degrade residual organic matter and disrupt colloidal stability within a wide range, including 30 mA / cm 2 It offers the best overall performance with moderate power consumption.

[0042] Example 4

[0043] The wastewater from heparin sodium production contains 3.2% sodium chloride, 38,500 mg / L COD, 2.1% total protein, 0.6% sulfate, and a pH of 6.8. 200 kg of wastewater was pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. Dilute sulfuric acid was added to adjust the pH to 4.0 under stirring. The tank was then heated to 75°C using the heating jacket and maintained at this temperature with stirring for 30 minutes. Non-ionic polyacrylamide was added to the tank at a dosage of 3 mg per liter of wastewater. After stirring, the mixture was sent to a solid-liquid separator for solid-liquid separation, yielding protein precipitate and a first filtrate. The first filtrate entered the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. The electrolytic cell was equipped with a titanium-based coated electrode assembly with a ruthenium-iridium oxide coating, with a plate spacing of 2 cm, and operated at a current density of 30 mA / cm². 2 Electrolysis was performed under specific conditions to obtain a second filtrate. The second filtrate entered the pH adjustment tank of the nanofiltration separation unit, where the pH was adjusted to 6.0, 7.0, and 8.0, respectively. After passing through a security filter, it entered the nanofiltration membrane module. The nanofiltration membrane module was filled with polyamide composite nanofiltration membranes with molecular weight cutoffs of 150 Da, 300 Da, and 500 Da, respectively. Separation was performed under operating pressures of 0.5 MPa, 1.2 MPa, and 2.0 MPa, respectively, to obtain permeate and concentrate. The permeate entered the reverse osmosis concentration unit, was pressurized to an operating pressure of 4.0 MPa by a high-pressure pump, and then entered the seawater desalination reverse osmosis membrane module for concentration, yielding sodium chloride concentrate and recycled water. The experimental results under different conditions are as follows:

[0044] It can be seen that nanofiltration membranes with molecular weight cutoffs of 150–500 Da can effectively separate sodium chloride from organic matter and sulfates, with the 300 Da membrane exhibiting the best overall performance in terms of sodium chloride permeability and organic matter rejection rate.

[0045] Example 5

[0046] The wastewater from heparin sodium production contains 4.5% sodium chloride, 48,000 mg / L COD, 2.8% total protein, 0.7% sulfate, and a pH of 6.5. 200 kg of wastewater was pumped into an acidification and coagulation tank equipped with a heating jacket and a stirrer. Dilute sulfuric acid was added to adjust the pH to 4.5 under stirring. The tank was then heated to 65°C using the heating jacket and maintained at this temperature with stirring for 50 minutes. Non-ionic polyacrylamide was added to the tank at a dosage of 4 mg per liter of wastewater. After stirring, the mixture was fed into a horizontal screw centrifuge for solid-liquid separation, yielding protein precipitate and a first filtrate. The first filtrate entered the electrolytic cell of the electrochemical oxidation unit from the liquid phase outlet of the solid-liquid separator. The electrolytic cell was equipped with a titanium-based coated electrode assembly with a ruthenium-iridium oxide coating, with an electrode spacing of 2.5 cm, and a current density of 45 mA / cm². 2 Electrolysis was performed under specific conditions to obtain a second filtrate. The second filtrate entered the pH adjustment tank of the nanofiltration separation unit, where the pH was adjusted to 7.5. After passing through a security filter, it entered the nanofiltration membrane module. The nanofiltration membrane module was filled with a polyamide composite nanofiltration membrane with a molecular weight cutoff of 400 Daltons. Separation was performed under an operating pressure of 1.8 MPa to obtain permeate and concentrate. The permeate entered the reverse osmosis concentration unit, was pressurized to an operating pressure of 5.5 MPa by a high-pressure pump, and then entered the seawater desalination reverse osmosis membrane module for concentration to obtain sodium chloride concentrate and recycled water. The sodium chloride concentrate had a sodium chloride concentration of 115 g / L and was transported to a brine recycling tank for reuse in the ion exchange elution process in heparin sodium production. The recycled water had a conductivity of 100 μS / cm and was reused as boiler feedwater. The concentrate discharged from the nanofiltration membrane module underwent further treatment using a wet oxidation process. The experimental results are as follows:

[0047] It can be seen that the method provided by the present invention can effectively treat high-concentration heparin sodium production wastewater and achieve dual resource recovery of protein and sodium chloride.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for treating wastewater from heparin sodium production, characterized in that, Includes the following steps: S1: Adjust the pH of the heparin sodium production wastewater to 3.5-5.0, heat it to 60-90℃, and add a coagulant to denature and coagulate the proteins in the water. Then, separate the solid and liquid to obtain protein precipitate and the first filtrate. S2: The first filtrate is fed into an electrolytic cell, using titanium-coated electrodes as the anode and cathode, at a current density of 10–50 mA / cm². 2 Electrolysis was performed under the specified conditions to obtain the second filtrate; S3: Adjust the pH of the second filtrate to 6.0-8.0, and then separate it through a nanofiltration membrane with a molecular weight cutoff of 150-500 Daltons to obtain a permeate mainly containing sodium chloride and a concentrate containing organic matter and polyvalent salts. S4: The permeate is concentrated through a reverse osmosis membrane to obtain sodium chloride concentrate and recycled water; the sodium chloride concentrate is recycled in the heparin sodium production process.

2. The method according to claim 1, characterized in that, In step S1, the coagulant is nonionic polyacrylamide, and the dosage is 1-5 mg per liter of wastewater; the heating and heat preservation time is 10-60 minutes.

3. The method according to claim 1, characterized in that, In step S2, the coating of the titanium-based coated electrode is a ruthenium-iridium oxide coating, and the distance between the anode and cathode plates is 1 to 3 cm.

4. The method according to claim 1, characterized in that, In step S3, the nanofiltration membrane is a polyamide composite nanofiltration membrane with a magnesium sulfate rejection rate of not less than 95% and a sodium chloride rejection rate of not more than 15%; the operating pressure is 0.5 to 2.0 MPa.

5. The method according to claim 1, characterized in that, In step S4, the reverse osmosis membrane is a seawater desalination reverse osmosis membrane, and the operating pressure is 3.0 to 5.5 MPa; the sodium chloride concentration of the obtained sodium chloride concentrate is 80 to 120 g / L, and the conductivity of the obtained recycled water is less than 150 μS / cm.

6. The method according to claim 1, characterized in that, The sodium chloride concentrate is reused in the ion exchange elution process or salt hydrolysis process in the production of heparin sodium.

7. The method according to claim 1, characterized in that, It also includes step S5, which involves subjecting the concentrate obtained in step S3 to anaerobic biological treatment or wet oxidation treatment.

8. A device for treating wastewater from heparin sodium production, characterized in that, Including those connected sequentially along the direction of water flow: A protein coagulation separation unit includes an acidification coagulation tank with a heating jacket and a stirrer, and a solid-liquid separator connected to the outlet of the acidification coagulation tank. An electrochemical oxidation unit includes an electrolytic cell and a titanium-based coated electrode assembly installed therein, wherein the inlet of the electrolytic cell is connected to the liquid phase outlet of the solid-liquid separator; A nanofiltration separation unit includes a pH adjustment tank, a security filter, and a nanofiltration membrane assembly connected in sequence, wherein the inlet of the nanofiltration membrane assembly is connected to the outlet of the electrochemical oxidation unit; A reverse osmosis concentration unit includes a high-pressure pump and a reverse osmosis membrane module, wherein the inlet of the reverse osmosis membrane module is connected to the permeate outlet of the nanofiltration membrane module; And a brine recycling tank connected to the concentrate outlet of the reverse osmosis membrane module.

9. The equipment for treating heparin sodium production wastewater according to claim 8, characterized in that, The solid-liquid separator is a horizontal screw centrifuge or a plate and frame filter press.

10. The equipment for treating heparin sodium production wastewater according to claim 8, characterized in that, The nanofiltration membrane in the nanofiltration membrane assembly is a polyamide composite membrane with a molecular weight cutoff of 150 to 500 Daltons.

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