A method for treating high-concentration fosfomycin sodium wastewater and recovering phosphorus and nitrogen

Abstract

This invention provides a method for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen. The method involves hydrothermal catalytic hydrothermal hydrolysis of the high-concentration sodium fosfomycin wastewater in a hydrothermal reactor. After hydrolysis, the wastewater is preheated by superheated steam obtained through flash evaporation. The resulting oil-water mixture is used as fuel in an incinerator to heat the oil, which serves as the heating medium for the hydrothermal reactor. The water layer after hydrothermal reaction is cooled in a crystallizer to precipitate disodium hydrogen phosphate. The wastewater discharged from the crystallizer enters a precipitation reactor, where magnesium salts are added to obtain struvite. This method completely degrades organic matter, effectively recovers organic phosphorus and organic nitrogen from the wastewater, and the superheated steam and oil layer generated during hydrolysis can be recovered as heating sources. The method uses simple equipment, has low energy consumption, and is economical.

Description

Technical Field

[0001] This invention relates to the field of high-concentration pharmaceutical wastewater treatment technology, and in particular to a method for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen. Background Technology

[0002] Fosfomycin sodium is a commonly used broad-spectrum antibiotic, belonging to the disodium epoxide phosphate class of compounds. It typically appears as a white or off-white crystalline powder, readily soluble in water, and its aqueous solution is weakly alkaline. Fosfomycin sodium has significant applications in the pharmaceutical field, primarily used to treat infectious diseases caused by various Gram-positive and Gram-negative bacteria. From a molecular structural perspective, fosfomycin sodium contains characteristic functional groups such as epoxy groups and phosphonic acid groups, making its chemical structure relatively stable and resistant to degradation.

[0003] The typical industrial production process of fosfomycin sodium uses propynyl alcohol as the main raw material, which reacts with PCl3 to synthesize a levoglucosamine intermediate (levo-fosfomycin sodium, dextro-phenylethylamine). Further conversion yields the target product, fosfomycin sodium. The production process generates a large amount of complex wastewater. This wastewater is characterized by high organic matter concentration, high pollution load, and poor biodegradability. Nitrogen and phosphorus coexist in multiple forms, resulting in a complex composition. Especially in the mother liquor and product washing wastewater, high concentrations of organic nitrogen and organic phosphorus compounds are often concentrated, accompanied by a certain amount of inorganic salts. These pollutants overlap and interact, increasing the complexity of the wastewater quality and significantly raising the technical difficulty of subsequent treatment and achieving discharge standards.

[0004] High-concentration sodium fosfomycin wastewater has a high COD content, reaching 100,000 to 200,000 mg / L, and contains a large amount of phosphorus- and nitrogen-containing organic matter, which is difficult to degrade using common water treatment processes. Wet oxidation, using air or oxygen as an oxidant, can decompose high-concentration sodium fosfomycin wastewater into inorganic substances such as CO2 and H2O or small-molecule organic matter under high temperature (150-350℃) and high pressure (0.5-20MPa) conditions. However, this method is energy-intensive, requires complex equipment and processes, and has a low wastewater degradation rate.

[0005] To address this issue, this invention provides a hydrothermal catalytic hydrolysis treatment method and process that eliminates the need for oxidants such as oxygen or air, and requires no pressurization. It utilizes high temperature and hydrothermal self-generated high pressure to degrade organic matter through a hydrolysis reaction. The recovery of superheated steam and the recovery of the oil layer generated after hydrothermal hydrolysis are used as heating media to provide the heat required for the hydrothermal reaction, thereby effectively improving the energy consumption of the reaction process. This method and process are far superior to currently used wet oxidation technologies in terms of COD degradation, phosphorus and nitrogen recovery from wastewater, as well as in terms of process equipment costs and operating energy consumption. Summary of the Invention

[0006] The purpose of this invention is to provide a method for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen. This method treats high-concentration sodium fosfomycin production wastewater without the need for oxidants or pressurization. Compared with wet oxidation, it not only has lower equipment and operating costs, but also a higher COD degradation rate and greater nitrogen and phosphorus recovery rate, resulting in significant economic and environmental benefits.

[0007] To achieve some or all of the above objectives or other objectives, this application provides the following technical solution: in 200~260 o At temperature C, reaction time 2-6 h, pH=10, using Al2O3-supported AlCl3-FeCl3 as catalyst, high-concentration sodium fosfomycin wastewater was hydrothermally catalyzed and hydrolyzed. While degrading the organic matter in the wastewater, organic phosphorus and organic nitrogen were converted into inorganic phosphorus and inorganic nitrogen and released. A large amount of inorganic phosphorus was recovered by cooling and precipitation of disodium hydrogen phosphate. The remaining inorganic phosphorus and inorganic nitrogen were recovered by adding magnesium salt to obtain struvite precipitate. The specific method includes: high-concentration sodium fosfomycin wastewater first enters a storage tank for preliminary preheating, then undergoes further preheating via a heat exchanger before entering a hydrothermal reactor. A hydrolysis reaction takes place in the reactor, and the resulting liquid is an oil-water mixture. The wastewater then enters a flash separation tower for flash evaporation and oil-water separation. Steam from the flash separation tower serves as the heat medium in the heat exchanger, and the hot water discharged from the heat exchanger enters the storage tank jacket for preheating the wastewater. The water layer separated from the flash separation tower is filtered and then cooled in a crystallizer to precipitate disodium hydrogen phosphate. The wastewater discharged from the crystallizer enters a sedimentation tank, where magnesium salts are added to obtain struvite. The oil layer separated from the flash separation tower enters an incinerator to heat the hot oil in a hot oil storage tank. The heated hot oil enters the spiral coil of the hydrothermal reactor as the heating medium for the hydrothermal reaction. The hot oil exiting the spiral coil of the hydrothermal reactor returns to the hot oil storage tank in the incinerator for reheating and recycling.

[0008] Furthermore, the hydrothermal catalytic hydrolysis reaction is carried out in a hydrothermal reactor; the catalyst is an Al2O3-supported AlCl3-FeCl3 composite catalyst, the particle size of the silica gel catalyst support is φ3~5mm, and the loading amount is 1 / 4~1 / 3 of the volume of high-concentration sodium fosfomycin wastewater.

[0009] Furthermore, the silica gel was immersed in an aqueous solution containing AlCl3 and FeCl3 and refluxed for 2-4 hours at a temperature of 60-80°C. o C.

[0010] Furthermore, steam is generated by flash evaporation in the upper part of the flash separation tower, and oil-water separation is carried out in the lower part of the flash tower.

[0011] Furthermore, the water layer separated by the flash separation tower is filtered and then enters the crystallizer, where the pH is adjusted to 7.5-9.5 and cooled to 8-15 degrees Celsius. o At temperature C, after 1 to 4 hours, solid disodium hydrogen phosphate is precipitated.

[0012] Furthermore, the wastewater discharged from the crystallizer is introduced into a sedimentation reaction tank, the pH is adjusted to 9.5, magnesium sulfate or magnesium chloride is added, the Mg:P ratio is controlled to 1.2, and the reaction time is 1~2 h to obtain solid struvite precipitate.

[0013] The beneficial effects of this invention are as follows: The method and process for treating high-concentration sodium fosfomycin wastewater provided by this invention do not require the addition of oxidants such as oxygen or air, nor do they require pressurization. They utilize high temperature and hydrothermal self-generated high pressure to degrade organic matter through a hydrothermal catalytic hydrolysis reaction. The degradation rate of COD in the wastewater can be adjusted by the reaction temperature, reaction time, and catalyst, reaching over 60-95%. Organic phosphorus in the wastewater is converted into inorganic disodium hydrogen phosphate for recovery, and organic nitrogen in the wastewater is converted into struvite for recovery by adding magnesium salts. The method and process of this invention have a significantly higher degradation rate for high-concentration phosphorus and nitrogen-containing wastewater, as well as a much higher recovery rate for phosphorus and nitrogen than currently used wet oxidation technologies. Furthermore, the equipment costs and daily operating costs are lower than those of wet oxidation technologies. Attached Figure Description

[0014] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the hydrothermal reactor of the present invention; Figure 3 This is a schematic diagram of the structure of the flash separation tower of the present invention; Figure 4 This is a schematic diagram of the filter structure of the present invention.

[0015] In the diagram: 1. Storage tank, 2. Heat exchanger, 3. Hydrothermal reactor, 4. Flash separation tower, 5. Filter, 6. Crystallizer, 7. Precipitation reactor, 8. Incinerator, 9. Hot oil storage tank, 10. Storage tank jacket, 11. Spiral coil, 12. Insulation layer, 13. Hot oil inlet, 14. Hot oil outlet, 15. Baffle, 16. Oil layer, 17. Water layer, 18. Sand filter tank, 19. PP cotton tank, 20. Activated carbon tank, 21. Ultrafiltration membrane tank. Detailed Implementation

[0016] The implementation process of the present invention will be further described below with reference to the accompanying drawings. The following non-limiting embodiments will enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0017] See Figure 1-4A system for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen from the wastewater includes: a storage tank 1, a heat exchanger 2, a hydrothermal reactor 3, a flash separation tower 4, a filter 5, a crystallizer 6, a precipitation reactor 7, an incinerator 8, a hot oil storage tank 9, and a storage tank jacket 10.

[0018] A method for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen: at 200~260 oC At a given temperature, reaction time of 2–6 h, and pH = 10, AlCl3-FeCl3 supported on Al2O3 was used as a catalyst for hydrothermal catalytic hydrolysis of high-concentration sodium fosfomycin production wastewater. While degrading organic matter in the wastewater, organic phosphorus and organic nitrogen were converted into inorganic phosphorus and inorganic nitrogen. A large amount of inorganic phosphorus was recovered by cooling and precipitation of disodium hydrogen phosphate. The remaining inorganic phosphorus and inorganic nitrogen were recovered by adding magnesium salts to obtain struvite precipitate.

[0019] The specific method includes: high-concentration sodium fosfomycin wastewater first enters the storage tank 1 for preliminary preheating, and then enters the hydrothermal reactor 3 after further preheating by the heat exchanger 2. Hydrolysis reaction is carried out in the hydrothermal reactor 3, which degrades the organic matter in the wastewater into an oil-water mixture, and converts the organic phosphorus and organic nitrogen in it into inorganic phosphorus and inorganic nitrogen and releases them.

[0020] The wastewater from the hydrothermal reactor 3 enters the flash separation tower 4 for flash evaporation. The steam from the upper part of the flash separation tower 4 serves as the heat medium in the heat exchanger 2. The hot water discharged from the heat exchanger 2 enters the storage tank jacket 10 for preheating the wastewater. The oil-water mixture from the lower part of the flash separation tower 4 undergoes stratification. The oil layer enters the incinerator 8 as fuel for heating the hot oil. The heated oil serves as the heat medium in the spiral coil 11 of the hydrothermal reactor 3 to heat the wastewater inside the reactor. The hot oil from the hydrothermal reactor 3 returns to the hot oil storage tank 9 of the incinerator 8 for heating and recycling. The water layer separated from the flash separation tower 4 is filtered through the filter 5 and then enters the crystallizer 6, where it is cooled and precipitates to obtain disodium hydrogen phosphate crystals. The wastewater from the crystallizer 6 enters the sedimentation tank, where magnesium salts are added to obtain struvite for recovery.

[0021] The method for recovering inorganic phosphorus is as follows: the water layer separated by flash separation tower 4 enters crystallizer 6, the pH is adjusted to 7.5~9.5, and the water is cooled to 8~15 degrees Celsius. o At temperature C, solid crystals of disodium hydrogen phosphate were obtained after 1 to 4 hours.

[0022] The method for recovering inorganic nitrogen is as follows: wastewater discharged from crystallizer 6 is fed into precipitation reactor 7, pH is adjusted to 9.5, magnesium sulfate or magnesium chloride is added, Mg:P = 1.2 is controlled, and the reaction time is 1-2 h to obtain solid struvite precipitate.

[0023] The hydrothermal catalytic hydrolysis process is carried out in a hydrothermal reactor 3. The catalyst is an AlCl3-FeCl3 composite catalyst supported on silica gel. The silica gel support has a particle size of φ3~5mm and a loading amount of 1 / 4~1 / 3 of the wastewater volume.

[0024] The method for preparing the silica-supported AlCl3-FeCl3 composite catalyst is as follows: silica gel is immersed in a solution containing AlCl3 and FeCl3 and refluxed for 2-4 hours at a temperature of 60-80°C. o C.

[0025] The hydrothermal reaction is carried out in hydrothermal reactor 3 at a temperature of 200~260°C. o At a temperature of C, with a reaction time of 2-6 hours, hydrothermal catalytic hydrolysis of high-concentration sodium fosfomycin wastewater resulted in a COD of 200,000 mg / L, total phosphorus of 40,000 mg / L, and total nitrogen of 4,000 mg / L. At 240°C... o At a temperature of C, a reaction time of 3 hours, and the addition of 100 g / L silica-supported AlCl3-FeCl3 catalyst, hydrothermal catalytic hydrolysis can achieve a COD removal rate of 60%, recovering 18000~20000 mg / L of inorganic phosphorus and 1800~2000 mg / L of inorganic nitrogen. The reaction was carried out at 240 °C. o At temperature C, with a reaction time of 6 hours and the addition of 100 g / L silica-supported AlCl3-FeCl3 catalyst, the catalytic hydrolysis of the hot water can achieve a COD removal rate of over 80%, and recover 25,000~30,000 mg / L of inorganic phosphorus and 2,500~3,000 mg / L of nitrogen.

[0026] Specifically, high-concentration sodium fosfomycin wastewater with COD of 200,000 mg / L, total phosphorus of 40,000 mg / L, and total nitrogen of 4,000 mg / L first enters storage tank 1 for preliminary preheating, then enters heat exchanger 2 for further preheating, and finally enters hydrothermal reactor 3, where it is reacted at a temperature of 240°C. o Hydrothermal catalytic hydrothermal hydrolysis is carried out at temperature C for 6 hours. The wastewater after the reaction enters flash separation tower 4 for flash evaporation. The steam exiting from the upper part of the baffle 15 of flash separation tower 4 serves as the heating medium and enters heat exchanger 2. The hot water leaving the heat exchanger enters the storage tank jacket 10 for preheating the raw water. The wastewater at the bottom of flash separation tower 4 undergoes oil-water separation. The separated oil layer 16 enters incinerator 1 as fuel to heat the hot oil in hot oil storage tank 9. The heated hot oil enters the spiral coil 11 hot oil inlet 13 in the hydrothermal reactor 3. The hot oil exiting from the spiral coil 11 hot oil outlet 14 in the hydrothermal reactor returns to the hot oil storage tank 9 on the incinerator for reheating and recycling.

[0027] The water layer 17 separated from the flash separation tower 4 enters the filter 5, and is filtered through the sand filter tank 18, PP cotton tank 19, activated carbon tank 20, and ultrafiltration membrane tank 21 respectively, before entering the crystallizer 6, where the pH is adjusted to 7.5~9.5 and cooled to 8~15 degrees Celsius. o At temperature C, for 2-6 hours, solid disodium hydrogen phosphate is obtained.

[0028] The wastewater discharged from crystallizer 6 enters sedimentation reactor 7, the pH is adjusted to 9.5, magnesium sulfate or magnesium chloride is added, Mg:P=1.2, the reaction time is 1~2 h, and solid struvite precipitate is obtained.

Claims

1. A method for treating high-concentration sodium fosfomycin wastewater and recovering phosphorus and nitrogen, characterized in that: Between 200 and 260 o At temperature C, reaction time 2-6 h, pH=10, using Al2O3-supported AlCl3-FeCl3 as catalyst, high-concentration sodium fosfomycin wastewater was hydrothermally catalyzed and hydrolyzed. While degrading the organic matter in the wastewater, organic phosphorus and organic nitrogen were converted into inorganic phosphorus and inorganic nitrogen and released. A large amount of inorganic phosphorus was recovered by cooling and precipitation of disodium hydrogen phosphate. The remaining inorganic phosphorus and inorganic nitrogen were recovered by adding magnesium salt to obtain struvite precipitate. The specific method includes: high-concentration sodium fosfomycin wastewater first enters a storage tank for preliminary preheating, then further preheats through a heat exchanger before entering a hydrothermal reactor for hydrolysis. The resulting liquid is an oil-water mixture. The wastewater then enters a flash separation tower for flash evaporation and oil-water separation. The steam from the flash separation tower acts as a heat medium in the heat exchanger, and the hot water discharged from the heat exchanger enters the jacket of the storage tank for preheating the wastewater. The water layer separated from the flash separation tower is filtered and then cooled in a crystallizer to precipitate disodium hydrogen phosphate. The wastewater discharged from the crystallizer enters a sedimentation tank, where magnesium salts are added to obtain struvite. The oil layer separated from the flash separation tower enters an incinerator to heat the hot oil in the hot oil storage tank. The heated hot oil enters the spiral coil of the hydrothermal reactor as a heating medium for the hydrothermal reaction, and the hot oil from the spiral coil returns to the hot oil storage tank in the incinerator for reheating and recycling.

2. The method for treating high-concentration sodium fosfomycin wastewater according to claim 1, characterized in that: The hydrothermal catalytic hydrolysis reaction is carried out in a hydrothermal reactor; the catalyst is an Al2O3-supported AlCl3-FeCl3 composite catalyst, the particle size of the silica gel catalyst support is φ3~5mm, and the loading amount is 1 / 4~1 / 3 of the volume of high-concentration sodium fosfomycin wastewater.

3. The method for preparing the catalyst according to claim 2, characterized in that: The silica gel was immersed in an aqueous solution containing AlCl3 and FeCl3 and refluxed for 2-4 hours at a temperature of 60-80°C. o C.

4. The method for treating high-concentration sodium fosfomycin wastewater according to claim 1, characterized in that: Steam is generated by flash evaporation in the upper part of the flash separation tower, and oil-water separation is carried out in the lower part of the flash tower.

5. The method for recovering phosphorus according to claim 1, characterized in that: The water layer separated by the flash evaporation separator is filtered and then enters the crystallizer, where the pH is adjusted to 7.5-9.5 and cooled to 8-15 degrees Celsius. o At temperature C, after 1 to 4 hours, solid disodium hydrogen phosphate is precipitated.

6. The method for recovering nitrogen according to claim 1, characterized in that: Wastewater discharged from the crystallizer is fed into a sedimentation reaction tank, the pH is adjusted to 9.5, magnesium sulfate or magnesium chloride is added, the Mg:P ratio is controlled to 1.2, and the reaction time is 1-2 hours to obtain solid struvite precipitate.

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