N-methyl pyrrolidone wastewater treatment system

Abstract

The utility model discloses an N-methyl pyrrolidone wastewater treatment system which comprises an adjusting tank, the water outlet end of the adjusting tank is connected with the water inlet end of an electrochemical reaction tank, the water outlet end of the electrochemical reaction tank is connected with the water inlet end of a UASB (Upflow Anaerobic Sludge Blanket) anaerobic tank, and the water outlet end of the UASB anaerobic tank is connected with the water inlet end of an anoxic tank; the water outlet end of the anoxic tank is connected with the water inlet end of the aerobic tank, the water outlet end of the aerobic tank is connected with the water inlet end of the MBR tank, and the sludge output end of the MBR tank is connected with the UASB anaerobic tank. According to the utility model, an electrochemical process, a UASB anaerobic process, an AO biochemical process and an MBR membrane filtration process are mainly combined to treat high-COD (Chemical Oxygen Demand) N-methyl pyrrolidone wastewater, and the treatment effect is obvious.

Description

Technical Field

[0001] This utility model relates to an N-methylpyrrolidone wastewater treatment system, belonging to the field of wastewater treatment technology. Background Technology

[0002] N-methylpyrrolidone (NMP) wastewater primarily originates from multiple stages of lithium-ion battery production. Specifically, NMP, used as a solvent, volatilizes during the formulation, coating, and drying processes of lithium-ion battery cathodes, generating NMP waste liquid after being recovered by a recycling device. Furthermore, processes using NMP as a solvent in chemical production also produce wastewater containing high concentrations of COD and ammonia nitrogen. This wastewater includes not only distillation and amination wastewater from lithium-ion battery production but also wastewater from industrial production in fields such as semiconductors, synthetic fibers, and fine chemicals.

[0003] The sources of NMP wastewater can be summarized as follows: (1) Lithium battery production: including NMP volatilization and waste gas treatment in the processes of material preparation, coating and drying. (2) Chemical production: various chemical production processes that use NMP as a solvent. (3) Other industrial fields: such as semiconductors, chemical fibers and fine chemicals. These wastewaters have high concentrations of COD and ammonia nitrogen, and belong to the type of recalcitrant organic wastewater, which is difficult to treat. Therefore, we propose an N-methylpyrrolidone wastewater treatment system. Utility Model Content

[0004] The purpose of this invention is to provide an N-methylpyrrolidone wastewater treatment system with good treatment effect, stable effluent quality, and compliance with the Class II standard (indirect emission standard) of the electronic industry pollutant emission standard (GB 39731-2020).

[0005] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: an N-methylpyrrolidone wastewater treatment system, including an equalization tank, which collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater, and then sends it into subsequent treatment facilities. The outlet of the equalization tank is connected to the inlet of an electrochemical reactor to pre-degrade the wastewater, remove some COD, and improve the biodegradability of the wastewater. The outlet of the electrochemical reactor is connected to the inlet of a UASB anaerobic tank, mainly used for anaerobic biological treatment, breaking down large organic molecules into small organic acids, some of which are incompletely oxidized into methane and other organic compounds. The UASB anaerobic tank is connected to the inlet of the anoxic tank, which is connected to the inlet of the aerobic tank. The inlet of the aerobic tank is connected to the inlet of the MBR tank. The anoxic and aerobic process sections remove most of the COD in the water, decomposing it into water and CO. Nitrification and denitrification are performed on ammonia nitrogen and organic nitrogen, generating a nitrogen removal system to degrade total nitrogen. The MBR replaces the sedimentation tank, intercepting sludge and suspended solids (SS) to achieve wastewater treatment standards. The treated wastewater is then pumped to the plant's discharge point. The sludge output of the MBR tank is connected to the UASB anaerobic tank for sludge recirculation.

[0006] The aforementioned N-methylpyrrolidone wastewater treatment system includes a disinfection tank connected to the effluent end of the MBR equipment within the MBR tank, a clear water tank connected to the effluent end of the disinfection tank, and a sludge treatment device connected to the sludge output end of the MBR tank. The sludge treatment device further treats the sludge. The disinfection tank sterilizes and disinfects the biochemically treated water, and also partially removes residual COD and ammonia nitrogen. The system stores the biochemically treated wastewater and provides a certain retention time in the tank to complete the disinfection treatment of the wastewater.

[0007] In the aforementioned N-methylpyrrolidone wastewater treatment system, the inlet of the regulating tank is equipped with an inlet fine screen to intercept debris.

[0008] The aforementioned N-methylpyrrolidone wastewater treatment system includes an equalization tank connected to a pH adjustment device and a dosing system. The pH adjustment device can add alkali to the equalization tank, and the dosing system can add PAC and PAM to the equalization tank. A submersible agitator is installed in the equalization tank.

[0009] The aforementioned N-methylpyrrolidone wastewater treatment system is equipped with an insulating electric heating system in the anoxic tank, aerobic tank, and MBR tank to ensure water temperature and prevent low temperatures such as winter from affecting the treatment effect.

[0010] The aforementioned N-methylpyrrolidone wastewater treatment system includes a sludge treatment device comprising a sludge thickening tank, a sludge lift pump, and a sludge filter press. The sludge output end of the MBR tank is connected to the sludge thickening tank. The sludge thickening tank transports sludge to the sludge filter press via the sludge lift pump, enabling the storage and pre-concentration of sludge generated during the wastewater treatment process. The sludge at the bottom of the sludge thickening tank is lifted to the sludge filter press, further reducing the sludge moisture content to a certain percentage and decreasing the sludge volume.

[0011] The aforementioned N-methylpyrrolidone wastewater treatment system also includes an aeration system, which is connected to both the aerobic tank and the MBR tank to provide sufficient oxygen for the microorganisms and to act as a stirrer to prevent sedimentation at the bottom.

[0012] The aforementioned N-methylpyrrolidone wastewater treatment system includes an aeration system comprising a blower, aeration pipes, and aeration heads. The output end of the blower is connected to the aeration pipes via a pipe. There are at least two aeration pipes, which are installed at the bottom of the aerobic tank and the MBR tank. Aeration heads are evenly distributed on the aeration pipes.

[0013] The aforementioned N-methylpyrrolidone wastewater treatment system includes an aeration pipe fitting comprising a main pipe and branch pipes. Branch pipes are evenly distributed on both sides of the main pipe, with an angle of 15°-35° between the main pipe and the branch pipes. The cross-sectional area of ​​the main pipe's inner cavity is greater than the sum of the cross-sectional areas of the inner cavities of all the branch pipes. The aeration heads are evenly distributed on the upper side of each branch pipe. The different resistance losses of each branch pipe in a multi-branch parallel pipeline are the direct cause of uneven flow distribution in the branch pipes. Inclined branch sections can reduce the resistance loss of the branch pipes, and consistent angles can make the resistance of each branch pipe section the same. When the total resistance loss of each branch pipe in the parallel pipeline is small, the ratio of the cross-sectional area of ​​the main pipe to the sum of the cross-sectional areas of each branch pipe can be designed to be greater than 100%, resulting in better uniformity of flow distribution in each branch pipe.

[0014] In the aforementioned N-methylpyrrolidone wastewater treatment system, a check valve is installed on the connecting pipe between the blower and the aeration pipe.

[0015] Compared with existing technologies, this invention mainly adopts a combination of electrochemical process, UASB anaerobic process, AO biological process and MBR membrane filtration process to treat high COD N-methylpyrrolidone wastewater. The treatment effect is significant, and it can meet the requirements of Class II standard (indirect emission standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment. Moreover, the effluent quality is stable. At the same time, the aeration system of this invention has uniform and stable aeration volume, which significantly improves the treatment effect of AO biological process and MBR membrane filtration process. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the system of this utility model;

[0017] Figure 2 This is a schematic diagram of the aeration system structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the aeration pipe structure of this utility model.

[0019] Attached reference numerals: 1-Equalization tank, 2-Electrochemical reaction tank, 3-Insulated electric heating system, 4-UASB anaerobic tank, 5-Anoxic tank, 6-Aerobic tank, 7-MBR tank, 8-Disinfection tank, 9-Clear water tank, 10-Sludge treatment device, 11-pH adjustment device, 12-Dosing system, 13-Sludge thickening tank, 14-Sludge lift pump, 15-Sludge filter press, 16-Aeration system, 17-Blower, 18-Aeration fittings, 19-Aeration head, 20-Main pipe, 21-Branch pipe.

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0021] Embodiment 1 of this utility model: An N-methylpyrrolidone wastewater treatment system, comprising:

[0022] Equalization tank 1 collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater, and then sends it to subsequent treatment facilities.

[0023] The electrochemical reaction tank 2 is connected to the inlet of the equalization tank 1 at the outlet end. It pre-degrades the wastewater, removes some COD, and improves the biodegradability of the wastewater. The electrochemical process has a high removal rate of organic pollutants, with a COD removal rate of 30-90%. It can degrade toxic organic matter in wastewater that is difficult to degrade into carbon dioxide, water and minerals without selection, and convert non-biodegradable high-molecular organic matter into biodegradable small-molecule compounds, thereby improving the biodegradability of wastewater.

[0024] The UASB anaerobic tank 4 is connected to the inlet of the electrochemical reaction tank 2 at the outlet end. It is mainly used for anaerobic biological treatment, which breaks down large organic molecules to produce small organic acids. Some of these acids are incompletely oxidized into organic compounds such as methane, thereby improving the biodegradability of wastewater.

[0025] In the A / O process, the effluent end of the UASB anaerobic tank 4 is connected to the influent end of the anoxic tank 5, and the effluent end of the anoxic tank 5 is connected to the influent end of the aerobic tank 6. The anoxic and aerobic process section removes most of the COD in the water, decomposing it into water and CO2, and performs nitrification and denitrification treatment on ammonia nitrogen and organic nitrogen to generate a nitrogen removal system, thus completing the degradation of total nitrogen.

[0026] MBR tank 7 is connected to the inlet of the aerobic tank 6 via the outlet end. The MBR device replaces the sedimentation tank to intercept sludge and suspended solids (SS), completes the wastewater treatment to meet standards, and lifts the treated wastewater to the plant discharge point. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return.

[0027] The system combines electrochemical, UASB anaerobic, AO biochemical, and MBR membrane filtration processes to treat high-COD N-methylpyrrolidone wastewater. The treatment effect is significant, meeting the requirements of the Class II standard (indirect discharge standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment, and the effluent quality is stable.

[0028] Embodiment 2 of this utility model: An N-methylpyrrolidone wastewater treatment system, comprising:

[0029] Equalization tank 1 collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater, and then sends it to subsequent treatment facilities.

[0030] The electrochemical reaction tank 2 is connected to the inlet of the equalization tank 1 at the outlet end. It pre-degrades the wastewater, removes some COD, and improves the biodegradability of the wastewater. The electrochemical process has a high removal rate of organic pollutants, with a COD removal rate of 30-90%. It can degrade toxic organic matter in wastewater that is difficult to degrade into carbon dioxide, water and minerals without selection, and convert non-biodegradable high-molecular organic matter into biodegradable small-molecule compounds, thereby improving the biodegradability of wastewater.

[0031] The UASB anaerobic tank 4 is connected to the inlet of the electrochemical reaction tank 2 at the outlet end. It is mainly used for anaerobic biological treatment, which breaks down large organic molecules to produce small organic acids. Some of these acids are incompletely oxidized into organic compounds such as methane, thereby improving the biodegradability of wastewater.

[0032] In the A / O process, the effluent end of the UASB anaerobic tank 4 is connected to the influent end of the anoxic tank 5, and the effluent end of the anoxic tank 5 is connected to the influent end of the aerobic tank 6. The anoxic and aerobic process section removes most of the COD in the water, decomposing it into water and CO2, and performs nitrification and denitrification treatment on ammonia nitrogen and organic nitrogen to generate a nitrogen removal system, thus completing the degradation of total nitrogen.

[0033] MBR tank 7 is connected to the inlet of the aerobic tank 6 via the outlet end. The MBR device replaces the sedimentation tank to intercept sludge and suspended solids (SS), completes the wastewater treatment to meet standards, and lifts the treated wastewater to the plant discharge point. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return.

[0034] The MBR tank 7 contains a disinfection tank 8, which is connected to the outlet of the MBR equipment. The outlet of the disinfection tank 8 is connected to a clear water tank 9. The sludge output of the MBR tank 7 is connected to a sludge treatment device 10, which further treats the sludge. The disinfection tank 8 disinfects and sterilizes the biochemically treated water, and also partially removes residual COD and ammonia nitrogen. It stores the biochemically treated wastewater and provides a certain retention time in the tank to complete the disinfection process. The stored disinfected wastewater is then pumped to the plant's discharge point for discharge. If gravity flow is used during discharge, a water pump is not required; if water reuse is considered, a water pump can be used.

[0035] The system combines electrochemical, UASB anaerobic, AO biochemical, and MBR membrane filtration processes to treat high-COD N-methylpyrrolidone wastewater. The treatment effect is significant, meeting the requirements of the Class II standard (indirect discharge standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment, and the effluent quality is stable.

[0036] Embodiment 3 of this utility model: An N-methylpyrrolidone wastewater treatment system, comprising:

[0037] Equalization tank 1 collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater before it enters subsequent treatment facilities. The inlet of equalization tank 1 is equipped with an inlet fine screen to intercept impurities. Equalization tank 1 is connected to a pH adjustment device 11 and a dosing system 12. The pH adjustment device 11 can add alkali to equalization tank 1, and the dosing system 12 can add PAC and PAM to equalization tank 1. A submersible agitator is installed in equalization tank 1.

[0038] The electrochemical reaction tank 2 is connected to the inlet of the equalization tank 1 at the outlet end. It pre-degrades the wastewater, removes some COD, and improves the biodegradability of the wastewater. The electrochemical process has a high removal rate of organic pollutants, with a COD removal rate of 30-90%. It can degrade toxic organic matter in wastewater that is difficult to degrade into carbon dioxide, water and minerals without selection, and convert non-biodegradable high-molecular organic matter into biodegradable small-molecule compounds, thereby improving the biodegradability of wastewater.

[0039] The UASB anaerobic tank 4 is connected to the inlet of the electrochemical reaction tank 2 at the outlet end. It is mainly used for anaerobic biological treatment, which breaks down large organic molecules to produce small organic acids. Some of these acids are incompletely oxidized into organic compounds such as methane, thereby improving the biodegradability of wastewater.

[0040] In the A / O process, the effluent end of the UASB anaerobic tank 4 is connected to the influent end of the anoxic tank 5, and the effluent end of the anoxic tank 5 is connected to the influent end of the aerobic tank 6. The anoxic and aerobic process section removes most of the COD in the water, decomposing it into water and CO2, and performs nitrification and denitrification treatment on ammonia nitrogen and organic nitrogen to generate a nitrogen removal system, thus completing the degradation of total nitrogen.

[0041] MBR tank 7 is connected to the inlet of the aerobic tank 6 via the outlet end. The MBR device replaces the sedimentation tank to intercept sludge and suspended solids (SS), completes the wastewater treatment to meet standards, and lifts the treated wastewater to the plant discharge point. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return.

[0042] The MBR tank 7 contains a disinfection tank 8, which is connected to the outlet of the MBR equipment. The outlet of the disinfection tank 8 is connected to a clear water tank 9. The sludge output of the MBR tank 7 is connected to a sludge treatment device 10, which further treats the sludge. The disinfection tank 8 disinfects and sterilizes the biochemically treated water, and also partially removes residual COD and ammonia nitrogen. It stores the biochemically treated wastewater and provides a certain retention time in the tank to complete the disinfection process. The stored disinfected wastewater is then pumped to the plant's discharge point for discharge. If gravity flow is used during discharge, a water pump is not required; if water reuse is considered, a water pump can be used.

[0043] The system combines electrochemical, UASB anaerobic, AO biochemical, and MBR membrane filtration processes to treat high-COD N-methylpyrrolidone wastewater. The treatment effect is significant, meeting the requirements of the Class II standard (indirect discharge standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment, and the effluent quality is stable.

[0044] Specifically, the anoxic tank 5, the aerobic tank 6, and the MBR tank 7 are all equipped with an insulated electric heating system 3 to ensure water temperature and prevent low temperatures such as winter from affecting the treatment effect.

[0045] Embodiment 4 of this utility model: An N-methylpyrrolidone wastewater treatment system, comprising:

[0046] Equalization tank 1 collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater before it enters subsequent treatment facilities. The inlet of equalization tank 1 is equipped with an inlet fine screen to intercept impurities. Equalization tank 1 is connected to a pH adjustment device 11 and a dosing system 12. The pH adjustment device 11 can add alkali to equalization tank 1, and the dosing system 12 can add PAC and PAM to equalization tank 1. A submersible agitator is installed in equalization tank 1.

[0047] The electrochemical reaction tank 2 is connected to the inlet of the equalization tank 1 at the outlet end. It pre-degrades the wastewater, removes some COD, and improves the biodegradability of the wastewater. The electrochemical process has a high removal rate of organic pollutants, with a COD removal rate of 30-90%. It can degrade toxic organic matter in wastewater that is difficult to degrade into carbon dioxide, water and minerals without selection, and convert non-biodegradable high-molecular organic matter into biodegradable small-molecule compounds, thereby improving the biodegradability of wastewater.

[0048] The UASB anaerobic tank 4 is connected to the inlet of the electrochemical reaction tank 2 at the outlet end. It is mainly used for anaerobic biological treatment, which breaks down large organic molecules to produce small organic acids. Some of these acids are incompletely oxidized into organic compounds such as methane, thereby improving the biodegradability of wastewater.

[0049] In the A / O process, the effluent end of the UASB anaerobic tank 4 is connected to the influent end of the anoxic tank 5, and the effluent end of the anoxic tank 5 is connected to the influent end of the aerobic tank 6. The anoxic and aerobic process section removes most of the COD in the water, decomposing it into water and CO2, and performs nitrification and denitrification treatment on ammonia nitrogen and organic nitrogen to generate a nitrogen removal system, thus completing the degradation of total nitrogen.

[0050] MBR tank 7 is connected to the inlet of the aerobic tank 6 via the outlet end. The MBR device replaces the sedimentation tank to intercept sludge and suspended solids (SS), completes the wastewater treatment to meet standards, and lifts the treated wastewater to the plant discharge point. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return.

[0051] The sludge treatment device 10 includes a sludge thickening tank 13, a sludge lift pump 14, and a sludge filter press 15. The sludge output end of the MBR tank 7 is connected to the sludge thickening tank 13. The sludge thickening tank 13 transports sludge to the sludge filter press 15 through the sludge lift pump 14, which can realize the storage and pre-concentration of sludge generated in the wastewater treatment process, lift the sludge at the bottom of the sludge thickening tank to the sludge filter press, further reduce the sludge moisture content to 80%, and reduce the sludge volume.

[0052] The MBR tank 7 contains a disinfection tank 8, which is connected to the outlet of the MBR equipment. The outlet of the disinfection tank 8 is connected to a clear water tank 9. The sludge output of the MBR tank 7 is connected to a sludge treatment device 10, which further treats the sludge. The disinfection tank 8 disinfects and sterilizes the biochemically treated water, and also partially removes residual COD and ammonia nitrogen. It stores the biochemically treated wastewater and provides a certain retention time in the tank to complete the disinfection process. The stored disinfected wastewater is then pumped to the plant's discharge point for discharge. If gravity flow is used during discharge, a water pump is not required; if water reuse is considered, a water pump can be used.

[0053] The system combines electrochemical, UASB anaerobic, AO biochemical, and MBR membrane filtration processes to treat high-COD N-methylpyrrolidone wastewater. The treatment effect is significant, meeting the requirements of the Class II standard (indirect discharge standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment, and the effluent quality is stable.

[0054] Specifically, the anoxic tank 5, the aerobic tank 6, and the MBR tank 7 are all equipped with an insulated electric heating system 3 to ensure water temperature and prevent low temperatures such as winter from affecting the treatment effect.

[0055] Embodiment 5 of this utility model: An N-methylpyrrolidone wastewater treatment system, comprising:

[0056] Equalization tank 1 collects and stores production wastewater, performs homogenization and equalization treatment on the water quality, pressurizes and lifts the wastewater before it enters subsequent treatment facilities. The inlet of equalization tank 1 is equipped with an inlet fine screen to intercept impurities. Equalization tank 1 is connected to a pH adjustment device 11 and a dosing system 12. The pH adjustment device 11 can add alkali to equalization tank 1, and the dosing system 12 can add PAC and PAM to equalization tank 1. A submersible agitator is installed in equalization tank 1.

[0057] The electrochemical reaction tank 2 is connected to the inlet of the equalization tank 1 at the outlet end. It pre-degrades the wastewater, removes some COD, and improves the biodegradability of the wastewater. The electrochemical process has a high removal rate of organic pollutants, with a COD removal rate of 30-90%. It can degrade toxic organic matter in wastewater that is difficult to degrade into carbon dioxide, water and minerals without selection, and convert non-biodegradable high-molecular organic matter into biodegradable small-molecule compounds, thereby improving the biodegradability of wastewater.

[0058] The UASB anaerobic tank 4 is connected to the inlet of the electrochemical reaction tank 2 at the outlet end. It is mainly used for anaerobic biological treatment, which breaks down large organic molecules to produce small organic acids. Some of these acids are incompletely oxidized into organic compounds such as methane, thereby improving the biodegradability of wastewater.

[0059] In the A / O process, the effluent end of the UASB anaerobic tank 4 is connected to the influent end of the anoxic tank 5, and the effluent end of the anoxic tank 5 is connected to the influent end of the aerobic tank 6. The anoxic and aerobic process section removes most of the COD in the water, decomposing it into water and CO2, and performs nitrification and denitrification treatment on ammonia nitrogen and organic nitrogen to generate a nitrogen removal system, thus completing the degradation of total nitrogen.

[0060] MBR tank 7 is connected to the inlet of the aerobic tank 6 via the outlet end. The MBR device replaces the sedimentation tank to intercept sludge and suspended solids (SS), completes the wastewater treatment to meet standards, and lifts the treated wastewater to the plant discharge point. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return.

[0061] The sludge treatment device 10 includes a sludge thickening tank 13, a sludge lift pump 14, and a sludge filter press 15. The sludge output end of the MBR tank 7 is connected to the sludge thickening tank 13. The sludge thickening tank 13 transports sludge to the sludge filter press 15 through the sludge lift pump 14, which can realize the storage and pre-concentration of sludge generated in the wastewater treatment process, lift the sludge at the bottom of the sludge thickening tank to the sludge filter press, further reduce the sludge moisture content to 80%, and reduce the sludge volume.

[0062] The MBR tank 7 contains a disinfection tank 8, which is connected to the outlet of the MBR equipment. The outlet of the disinfection tank 8 is connected to a clear water tank 9. The sludge output of the MBR tank 7 is connected to a sludge treatment device 10, which further treats the sludge. The disinfection tank 8 disinfects and sterilizes the biochemically treated water, and also partially removes residual COD and ammonia nitrogen. It stores the biochemically treated wastewater and provides a certain retention time in the tank to complete the disinfection process. The stored disinfected wastewater is then pumped to the plant's discharge point for discharge. If gravity flow is used during discharge, a water pump is not required; if water reuse is considered, a water pump can be used.

[0063] The system combines electrochemical, UASB anaerobic, AO biochemical, and MBR membrane filtration processes to treat high-COD N-methylpyrrolidone wastewater. The treatment effect is significant, meeting the requirements of the Class II standard (indirect discharge standard) of the electronic industry pollutant discharge standard (GB 39731-2020) after wastewater treatment, and the effluent quality is stable.

[0064] Specifically, the anoxic tank 5, the aerobic tank 6, and the MBR tank 7 are all equipped with an insulated electric heating system 3 to ensure water temperature and prevent low temperatures such as winter from affecting the treatment effect.

[0065] Specifically, it also includes an aeration system 16, which is connected to both the aerobic tank 6 and the MBR tank 7 to provide sufficient oxygen for the microorganisms and to act as a stirrer to prevent sedimentation at the bottom. The aeration system 16 includes a blower 17, aeration pipes 18, and aeration heads 19. The output end of the blower 17 is connected to the aeration pipes 18 through a pipe. There are at least two aeration pipes 18, which are located at the bottom of the aerobic tank 6 and the MBR tank 7. Aeration heads 19 are evenly distributed on the aeration pipes 18. The aeration pipe fitting 18 includes a main pipe 20 and branch pipes 21. Branch pipes 21 are evenly distributed on both sides of the main pipe 20, with an angle between the main pipe 20 and the branch pipes 21 ranging from 15° to 35°. The cross-sectional area of ​​the inner cavity of the main pipe 20 is greater than the sum of the cross-sectional areas of the inner cavities of all the branch pipes 21. Aeration heads 19 are evenly distributed on the upper side of each branch pipe 21. The different resistance losses of each branch pipe in a multi-branch parallel pipeline are the direct cause of uneven flow distribution. Inclined branch sections can reduce the resistance loss of the branch pipes 21, and consistent angles can ensure that the resistance of each branch pipe 21 is the same. When the total resistance loss of each branch pipe 21 in the parallel pipeline is small, by designing the ratio of the cross-sectional area of ​​the main pipe 20 to the sum of the cross-sectional areas of all the branch pipes 21 to be greater than 1, the flow distribution uniformity of each branch pipe 21 is better. A check valve is installed on the connecting pipe between the blower 17 and the aeration pipe fitting 18.

[0066] The working principle of one embodiment of this utility model is as follows: During operation, wastewater is collected and stored in a regulating tank 1. A fine screen intercepts impurities, homogenizing the water quality. Simultaneously, alkali is added to the regulating tank 1 via a pH adjusting device 11 to adjust the wastewater pH to 6-6.5. PAC and PAM are added to the regulating tank 1 via a dosing system 12. The wastewater is then pressurized and pumped into an electrochemical reactor 2 for pre-degradation, removing some COD and improving its biodegradability. The wastewater then enters a UASB anaerobic tank 4, primarily for anaerobic biological treatment, breaking down large organic molecules into smaller organic acids, some of which are incompletely oxidized to methane and other organic compounds, further improving the wastewater's biodegradability. After further A / O treatment, the wastewater from the electrochemical reactor 2 enters the UASB anaerobic tank 4, where it remains for 15 hours before entering the aerobic tank. 6. The retention time is 15 hours. In the anoxic-aerobic process section, most of the COD in the water is removed, decomposing it into water and CO2. Ammonia nitrogen and organic nitrogen are nitrified and denitrified, generating nitrogen gas that is removed from the system, thus completing the degradation of total nitrogen. Then, the water enters the MBR tank 7 for filtration. The MBR device replaces the sedimentation tank to intercept sludge and SS. The sludge output end of the MBR tank 7 is connected to the UASB anaerobic tank 4 for sludge return. The water treated by the MBR flows into the disinfection tank 8. The disinfection tank 8 disinfects and sterilizes the biologically treated water and also has a partial removal effect on residual COD and ammonia nitrogen. The disinfected water is collected in the clear water tank 9. The disinfected wastewater stored in the clear water tank 9 is pumped to the plant's discharge point for discharge. The sludge output end of the MBR tank 7 is connected to the sludge treatment device 10, which further treats the sludge, reducing the sludge moisture content to 80% and reducing the sludge volume. In actual use, the COD of the wastewater in equalization tank 1 was 19900 mg / L and the TN was 149 mg / L. After treatment, the COD of the effluent was 400 mg / L and the TN was 6.30 mg / L. The treatment effect was obvious and the effluent quality was stable.

Claims

1. An N-methylpyrrolidone wastewater treatment system, characterized in that, The system includes an equalization tank (1), the outlet of which is connected to the inlet of an electrochemical reaction tank (2), the outlet of which is connected to the inlet of a UASB anaerobic tank (4), the outlet of which is connected to the inlet of an anoxic tank (5), the outlet of which is connected to the inlet of an aerobic tank (6), the outlet of which is connected to the inlet of an MBR tank (7), and the sludge output of the MBR tank (7) is connected to the UASB anaerobic tank (4).

2. The N-methylpyrrolidone wastewater treatment system according to claim 1, characterized in that, The MBR tank (7) is connected to a disinfection tank (8) at the outlet of the MBR equipment, and a clear water tank (9) is connected to the outlet of the disinfection tank (8). The sludge output end of the MBR tank (7) is connected to a sludge treatment device (10).

3. The N-methylpyrrolidone wastewater treatment system according to claim 1, characterized in that, The inlet of the regulating tank (1) is equipped with a fine inlet screen.

4. The N-methylpyrrolidone wastewater treatment system according to claim 3, characterized in that, The conditioning tank (1) is connected to a pH adjustment device (11) and a dosing system (12). The pH adjustment device (11) can add alkali to the conditioning tank (1), and the dosing system (12) can add PAC and PAM to the conditioning tank (1). The conditioning tank (1) is equipped with a submersible agitator.

5. The N-methylpyrrolidone wastewater treatment system according to claim 1, characterized in that, The anoxic tank (5), aerobic tank (6) and MBR tank (7) are all equipped with a heat preservation electric heating system (3).

6. The N-methylpyrrolidone wastewater treatment system according to claim 2, characterized in that, The sludge treatment device (10) includes a sludge thickening tank (13), a sludge lift pump (14), and a sludge filter press (15). The sludge output end of the MBR tank (7) is connected to the sludge thickening tank (13). The sludge thickening tank (13) transports sludge to the sludge filter press (15) through the sludge lift pump (14).

7. The N-methylpyrrolidone wastewater treatment system according to claim 1, characterized in that, It also includes an aeration system (16), which is connected to the aerobic tank (6) and the MBR tank (7) respectively.

8. The N-methylpyrrolidone wastewater treatment system according to claim 7, characterized in that, The aeration system (16) includes a blower (17), aeration pipes (18), and aeration heads (19). The output end of the blower (17) is connected to the aeration pipes (18) through a pipe. There are at least two aeration pipes (18). The aeration pipes (18) are set at the bottom of the aerobic tank (6) and the MBR tank (7). Aeration heads (19) are evenly distributed on the aeration pipes (18).

9. The N-methylpyrrolidone wastewater treatment system according to claim 8, characterized in that, The aeration pipe fitting (18) includes a main pipe (20) and branch pipes (21). The branch pipes (21) are evenly distributed on both sides of the main pipe (20). The included angle between the main pipe (20) and the branch pipes (21) is 15°-35°. The cross-sectional area of ​​the inner cavity of the main pipe (20) is greater than the sum of the cross-sectional areas of the inner cavities of each branch pipe (21). The aeration heads (19) are evenly distributed on the upper side of each branch pipe (21).

10. An N-methylpyrrolidone wastewater treatment system according to claim 9, characterized in that, A check valve is installed on the connecting pipe between the blower (17) and the aeration pipe (18).

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