DMF (Dimethyl Formamide) wastewater treatment system

Abstract

The DMF wastewater treatment system comprises a reactor, an air stripping tower, an accommodating tank, a sodium hydroxide solution storage tank and a flocculating agent storage tank, the reactor comprises a first input end and a second input end, the first input end is communicated with the DMF wastewater output port, the second input end is communicated with the sodium hydroxide solution storage tank, the flocculant storage tank and the gas inlet pipeline, the reactor comprises a first output end and a second output end, the first output end is communicated with the accommodating tank, and the second output end is communicated with the stripping tower; and a gas-liquid distribution assembly connected with the second input end and a floating foam adsorption assembly connected with the first output end are arranged in the reactor. The DMF wastewater treatment system can effectively improve the treatment efficiency of the DMF wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and specifically relates to a DMF wastewater treatment system. Background Art

[0002] DMF (N,N-dimethylformamide) wastewater is a kind of high-concentration organic wastewater, mainly derived from the production processes of chemical plants, pharmaceutical factories, leather processing factories, etc. Since DMF is often used during the processing and production in factories, the concentration of DMF in the wastewater is relatively high. Moreover, the molecular structure of DMF is stable and it is difficult to be degraded by microorganisms, which increases the difficulty of wastewater treatment. Secondly, DMF has certain toxicity and also poses a potential threat to the environment and human health. In addition to DMF, the wastewater may also contain other organic matters, inorganic salts, heavy metals and other impurities, further increasing the complexity of treatment.

[0003] A DMF wastewater treatment system is a device or process combination specifically used to treat industrial wastewater containing dimethylformamide (DMF). This system is generally composed of several devices connected in series, and thus can gradually and systematically treat the DMF wastewater discharged from factories. Regarding the treatment method of DMF wastewater, due to the strong biological toxicity of DMF itself and the secondary toxic substances generated during the degradation process, it is difficult to directly adopt microbial degradation treatment; generally, it includes physical treatment, chemical treatment and then microbial treatment. In the reactor, DMF can be hydrolyzed by heating to generate dimethylamine (DMA) and formic acid. The former needs additional stripping treatment, while the latter will corrode the equipment and reduce the service life of the reactor.

[0004] Before decomposing DMF sewage at high temperature, the sewage is generally filtered, but this filtration only targets large-particle solids. Excessive filtration accuracy will affect the filtration efficiency and lead to slow sewage treatment efficiency. If small particles in the sewage are not removed, it will cause scaling during the heating hydrolysis process, and adhere to the surface of the packing during the subsequent pipeline transportation process and stripping treatment, resulting in blockage of the pipeline and packing, and affecting the feeding of the reactor, thus affecting the treatment effect of DMF wastewater. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a DMF wastewater treatment system, which can effectively improve the treatment efficiency of DMF wastewater.

[0006] To solve the above technical problems, the present invention is solved by the following technical solutions: A DMF wastewater treatment system includes a reactor, a stripping tower, a holding tank, a sodium hydroxide solution storage tank, and a flocculant storage tank; the reactor includes a first input end and a second input end, the first input end is communicated with the DMF wastewater outlet, the second input end is communicated with the sodium hydroxide solution storage tank, the flocculant storage tank, and an intake pipeline, the reactor includes a first output end and a second output end, the first output end is communicated with the holding tank, the second output end is communicated with the stripping tower, and a gas-liquid distribution component connected to the second input end and a foam adsorption component connected to the first output end are arranged in the reactor; the treatment method of the DMF wastewater treatment system includes the following steps: 1) Inject DMF wastewater into the reactor; 2) Heat the DMF wastewater to 30-35°C, introduce a flocculant, then introduce gas through the intake pipeline, and adsorb the foam by the foam adsorption component until no more foam is generated; 3) Introduce sodium hydroxide solution to adjust the pH to 11-12.5, heat the DMF wastewater to 110-135°C, react for 80-120 minutes to hydrolyze DMF; 4) Introduce sodium hydroxide solution to adjust the pH value of the hydrolyzate to 11-12, introduce the hydrolyzate into the stripping tower, strip DMA in the stripping tower, and the stripped DMA is burned and decomposed into nitrogen and carbon dioxide by oxygen-rich air at a temperature above 800°C; 5) Add acid to the stripping residue to neutralize the pH value to 6-9 and then discharge it into the biochemical pool. This DMF wastewater treatment system hydrolyzes DMF to generate DMA and sodium formate under the conditions of 110-135°C and pH 11-12.5 to avoid the generation of formic acid to corrode the reactor, then introduce sodium hydroxide solution to adjust the pH value of the hydrolyzate to 11-12 to make dimethylamine in the free state, use the waste heat in the stripping tower to strip DMA, burn and decompose the stripped DMA into nitrogen and carbon dioxide, and then decompose the stripping residue by microorganisms in the biochemical pool after neutralization. And the DMF wastewater does not need fine filtration. Instead, small particles in the DMF wastewater are flocculated to form foam by introducing a flocculant and then introducing gas, and then adsorbed by the foam adsorption component into the holding tank, and the flocculation efficiency is improved by heating the DMF wastewater to 30-35°C. Since DMF in the DMF wastewater itself needs to be heated and hydrolyzed, the flocculation efficiency can be improved without additional energy consumption. Overall, the fine filtration step is omitted, the cost and time of fine filtration are saved, and the treatment efficiency of DMF wastewater is greatly improved.

[0007] In the above technical solution, preferably, the holding tank is connected with an absorption tower for adsorbing the tail gas of the holding tank.

[0008] In the above technical solution, preferably, the DMF wastewater treatment system includes at least two reactors connected in parallel. By providing multiple reactors connected in parallel, it is possible to clean and maintain the reactor that has stopped operating without stopping the operation by switching reactors.

[0009] In the above technical solution, preferably, the floating foam adsorption assembly includes a support frame fixed inside the reactor. A telescopic pipe fitting is rotatably arranged on the support frame and is driven to rotate by a first driving device. A bracket extends from the side of the telescopic pipe fitting. A roller driven by a second driving device is rotatably arranged on the bracket. A floating foam scraping strip is arranged on the bracket and is in contact with the roller. A floating foam accommodating space is formed between the floating foam scraping strip and the surface of the roller. A drawing pipe passes through the center of the telescopic pipe fitting, and the end of the drawing pipe is bent and extends into the accommodating space. The drawing pipe is connected to the accommodating tank, and a negative pressure pump is arranged on the drawing pipe. With this structure, the roller can be driven to rotate by the second driving device, so that the floating foam adheres to the surface of the roller, and the floating foam is scraped off by the floating foam scraping strip and retained in the floating foam accommodating space. The floating foam in the floating foam accommodating space is drawn out through the drawing pipe to the accommodating tank for collection by the adsorption action of the negative pressure pump.

[0010] In the above technical solution, preferably, the floating foam scraping strip has a convex strip facing the side of the roller, and the contact surface of the convex strip matches the arc surface of the outer wall of the roller. The top surface of the convex strip forms a floating foam guiding inclined surface that is higher on the side away from the drawing pipe than on the side close to the drawing pipe. The convex strip is in close contact with the surface of the roller and forms a floating foam converging area on the suction port side close to the drawing pipe. As the roller rotates, the floating foam on the surface of the roller is guided to the floating foam converging area. With this structure, the floating foam can be converged towards the suction port side of the drawing pipe by the rotation of the roller, preventing the floating foam from accumulating on the scraping strip and enabling the floating foam to be sucked out more quickly.

[0011] In the above technical solution, preferably, the telescopic pipe fitting includes an inner pipe fitting rotatably arranged on the support frame and an outer pipe fitting sleeved on the inner pipe fitting and capable of axial movement. An adjusting motor is arranged on the outer pipe fitting. A screw rod is arranged on the output shaft of the adjusting motor. A matching block is arranged inside the inner pipe fitting. The screw rod is in threaded connection with the matching block. The bracket is connected to the outer pipe fitting. With this structure, the lifting of the outer pipe fitting can be driven by the forward and reverse rotation of the adjusting motor, thereby adjusting the height of the roller so that the roller can be located at a suitable height in contact with the water surface.

[0012] In the above technical solution, preferably, a water level sensor is arranged on the outer wall of the telescopic pipe fitting, and the water level sensor is electrically connected to the adjusting motor. With this structure, the water level can be detected by the water level sensor, and the automatic adjustment of the height of the roller by the adjusting motor can be achieved through the control of the control device.

[0013] In the above technical solution, preferably, the gas-liquid distribution assembly includes a horizontal delivery pipe connected to the telescopic pipe fitting and a vertical delivery pipe connected to the horizontal delivery pipe. The second input end is connected to a vertically arranged guide sleeve located below the rotation center of the telescopic pipe fitting. A guide pipe passing through the guide sleeve is provided at the bottom of the rotation center of the horizontal delivery pipe. The guide pipe can lift and rotate within the guide sleeve. A plurality of one-way nozzles are arranged on the vertical delivery pipe. With this structure, the gas-liquid distribution assembly can not only be used to introduce gas and liquid at different depths of the wastewater, but also rotate with the rotation of the telescopic pipe fitting and can be used as a stirrer.

[0014] In the above technical solution, preferably, a first helical gear is provided at the top of the telescopic pipe fitting. The first helical gear meshes with a second helical gear at one end of the horizontal rotating shaft. A third helical gear at the other end of the horizontal rotating shaft meshes with a fourth helical gear on the output shaft of the first driving device. The first driving device is fixed to the reactor.

[0015] In the above technical solution, preferably, the second driving device includes a helical gear ring sleeved on the outer periphery of the telescopic pipe fitting. A plurality of guide rods are provided at the top of the helical gear ring. The guide rods pass through the guide holes of the support frame. A spring is arranged between the helical gear ring and the support frame. A fifth helical gear meshing with the helical gear ring is provided at the end of the drum. With this structure, there is no need to install an additional motor on the bracket to drive the drum to rotate. And due to the rotation of the bracket, installing a motor on the bracket will cause technical problems such as a more complex power supply structure and poor circuit sealing. In the process of the first driving device driving the telescopic pipe fitting to rotate and the drum revolving around the telescopic pipe fitting, the fifth helical gear on the drum meshes with the helical gear ring to make the drum rotate. The structure is simple. And when the telescopic pipe fitting expands and contracts, the elastic force of the spring can make the helical gear ring lift and does not affect the transmission of the drum.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This DMF wastewater treatment system hydrolyzes DMF to generate DMA and sodium formate under the conditions of 110 - 135 °C and pH 11 - 12.5, avoiding the generation of formic acid that corrodes the reactor. Then, sodium hydroxide solution is introduced to adjust the pH value of the hydrolysis solution to 11 - 12, making dimethylamine convert into the free state. The heat in the blow-off tower is used to blow off DMA, and the blown-off DMA is incinerated and decomposed into nitrogen and carbon dioxide. Then, the blow-off residue liquid is neutralized and decomposed by microorganisms in the biochemical pool. And the DMF wastewater does not need fine filtration. Instead, small particles in the DMF wastewater are flocculated to form foam by introducing a flocculant and then introducing gas. Then, the foam is adsorbed to the storage tank through the foam adsorption component, and the flocculation efficiency is improved by heating the DMF wastewater to 30 - 35 °C. Since the DMF in the DMF wastewater itself needs to be heated for hydrolysis, the flocculation efficiency can be improved without additional energy consumption. Overall, the fine filtration step is omitted, saving the cost and time of fine filtration, and greatly improving the treatment efficiency of DMF wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of Embodiment 1 of the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of the reactor in Embodiment 1 of the present invention.

[0019] Figure 3 It is a schematic cross-sectional view of the reactor in Embodiment 1 of the present invention.

[0020] Figure 4 It is Figure 3 a partial enlarged view of

[0021] Figure 5 It is a schematic diagram of the internal structure of the reactor in Embodiment 1 of the present invention.

[0022] Figure 6 It is a schematic diagram of the internal structure of the telescopic pipe fitting in Embodiment 1 of the present invention.

[0023] Figure 7 It is a schematic cross-sectional view of the cooperation between the drum and the foam scraping bar in Embodiment 1 of the present invention.

[0024] Figure 8 It is a schematic diagram of the structure of the foam scraping bar in Embodiment 1 of the present invention.

[0025] Figure 9 It is a schematic diagram of a partial internal structure of the reactor in Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be further described in detail below in conjunction with the drawings and the specific embodiments: Refer to Figures 1 to 8, Example 1, A DMF wastewater treatment system, comprising a reactor 1, a stripping tower 2, a holding tank 3, a sodium hydroxide solution storage tank 4, and a flocculant storage tank 5; the reactor 1 includes a first input end 6 and a second input end 7, the first input end 6 is communicated with the DMF wastewater outlet 8, the second input end 7 is communicated with the sodium hydroxide solution storage tank 4, the flocculant storage tank 5, and the intake pipe 10, the reactor 1 includes a first output end 11 and a second output end 12, the first output end 11 is communicated with the holding tank 3, the second output end 12 is communicated with the stripping tower 2, a gas-liquid distribution component 13 connected to the second input end 7 and a foam adsorption component 14 connected to the first output end 11 are arranged in the reactor 1; the treatment method of the DMF wastewater treatment system comprises the following steps: 1 Inject the DMF wastewater into the reactor 1: the DMF wastewater is injected into the reactor 1 after preliminary filtration; 2 Heat the DMF wastewater to 30-35 °C by steam, introduce a flocculant and then introduce gas through the intake pipe 10, and adsorb the foam by the foam adsorption component 14 until no more foam is generated; 3 Introduce sodium hydroxide solution to adjust the pH to 11-12.5, heat the DMF wastewater to 110-135 °C, and react for 80-120 minutes to hydrolyze the DMF; 4 Introduce sodium hydroxide solution to adjust the pH value of the hydrolyzate to 11-12, introduce the hydrolyzate into the stripping tower 2, strip DMA in the stripping tower 2, and the stripped DMA is burned and decomposed into nitrogen and carbon dioxide by oxygen-rich air at a temperature above 800 °C; 5 Add acid to the stripping residue to neutralize the pH to 6-9 and then discharge it into the biochemical pool. This DMF wastewater treatment system hydrolyzes DMF to generate DMA and sodium formate under the conditions of 110-135 °C and pH 11-12.5, avoiding the generation of formic acid to corrode the reactor 1; since dimethylamine forms strong hydrogen bonds with water molecules and exists in a large amount in an ionic state at room temperature, its volatility is significantly inhibited, resulting in great difficulty in stripping. By introducing sodium hydroxide solution to adjust the pH value of the hydrolyzate to 11-12, dimethylamine is converted into a free state, and DMA is stripped in the stripping tower 2 by strengthening mass transfer under the action of waste heat, and then the stripped DMA is burned and decomposed into nitrogen and carbon dioxide, and then the stripping residue is neutralized and decomposed by microorganisms in the biochemical pool; and the DMF wastewater does not need to be finely filtered, but small particles in the DMF wastewater are flocculated to form foam by introducing a flocculant and then introducing gas, and then adsorbed by the foam adsorption component 14 into the holding tank 3, and the flocculation efficiency is improved by heating the DMF wastewater to 30-35 °C. At this temperature, compared with low-temperature wastewater, the viscosity of the wastewater can be reduced and the flocculation effect can be improved, and compared with higher-temperature wastewater, the bubble stability is better, thus improving the air flotation effect. Since the DMF in the DMF wastewater itself needs to be heated and hydrolyzed, the flocculation efficiency can be improved without additional energy consumption, the fine filtration step is omitted as a whole, the cost and time of fine filtration are saved, and the treatment efficiency of the DMF wastewater is greatly improved.

[0027] In this embodiment, to adsorb the tail gas discharged from the storage tank 3, an absorption tower 15 for adsorbing the tail gas of the storage tank 3 is connected to the storage tank 3.

[0028] In this embodiment, the DMF wastewater treatment system includes at least two reactors 1 connected in parallel. By arranging a plurality of reactors 1 connected in parallel, it is possible to clean and maintain the reactor 1 that has stopped operating without stopping the operation by switching the reactors 1.

[0029] In this embodiment, the foam adsorption assembly 14 includes a support frame 16 fixed inside the reactor 1. A telescopic pipe fitting 18 driven to rotate by a first driving device 17 is rotatably arranged on the support frame 16. A bracket 19 extends from the side of the telescopic pipe fitting 18. A roller 21 driven by a second driving device 20 is rotatably arranged on the bracket 19. A foam scraping strip 22 that fits the roller 21 is arranged on the bracket 19. A foam accommodation space 23 is formed between the foam scraping strip 22 and the surface of the roller 21. A suction pipe 24 passes through the center of the telescopic pipe fitting 18. The end of the suction pipe 24 is bent and extends into the foam accommodation space 23. The suction pipe 24 is connected to the storage tank 3, and a negative pressure pump is arranged on the suction pipe 24. With this structure, the roller 21 can be driven to rotate by the second driving device 20, so that the foam adheres to the surface of the roller 21, and the foam is scraped off by the foam scraping strip 22 and stored in the foam accommodation space 23. The foam in the foam accommodation space 23 is sucked out through the suction pipe 24 to the storage tank 3 for collection by the adsorption action of the negative pressure pump.

[0030] In this embodiment, the foam scraping strip 22 has a convex strip 25 facing the roller 21 side, and the contact surface of the convex strip 25 matches the arc surface of the outer wall of the roller 21. The top surface of the convex strip 25 forms a foam guiding inclined surface 26 that is higher on the side away from the suction pipe 24 than on the side close to the suction pipe 24. The convex strip 25 is in close contact with the surface of the roller 21 and forms a foam converging area 27 on the suction port side close to the suction pipe 24. As the roller 21 rotates, the foam on the surface of the roller 21 is guided to the foam converging area 27. With this structure, the rotation of the roller 21 can converge the foam towards the suction port side of the suction pipe 24, preventing the foam from accumulating on the scraping strip and enabling the foam to be sucked out more quickly.

[0031] In this embodiment, the telescopic pipe fitting 18 includes an inner pipe fitting 28 rotatably arranged on the support frame 16 and an outer pipe fitting 29 sleeved on the inner pipe fitting 28 that can move axially. An adjustment motor 30 is arranged on the outer pipe fitting 29. A screw rod 31 is arranged on the output shaft of the adjustment motor 30. A mating block 32 is arranged inside the inner pipe fitting 28. The screw rod 31 is in threaded connection with the mating block 32. The bracket 19 is connected to the outer pipe fitting 29. With this structure, the lifting of the outer pipe fitting 29 can be driven by the forward and reverse rotation of the adjustment motor 30, thereby adjusting the height of the roller 21 so that the roller 21 can be located at a suitable height in contact with the water surface.

[0032] In this embodiment, a water level sensor 33 is provided on the outer wall of the telescopic pipe fitting 18, and the water level sensor 33 is electrically connected to the adjustment motor 30. With this structure, the water level can be detected by the water level sensor 33, and the adjustment motor 30 can automatically adjust the height of the roller 21 through the control of the control device.

[0033] In this embodiment, the gas-liquid distribution assembly 13 includes a horizontal delivery pipe 34 connected to the telescopic pipe fitting 18 and a vertical delivery pipe 35 connected to the horizontal delivery pipe 34. The second input end 7 is connected to a vertically arranged guide sleeve 36 located below the rotation center of the telescopic pipe fitting 18. A guide pipe 37 passing through the guide sleeve 36 is provided at the bottom of the rotation center of the horizontal delivery pipe 34. The guide pipe 37 can lift and rotate within the guide sleeve 36, and a number of one-way nozzles 38 are arranged on the vertical delivery pipe 35. With this structure, the gas-liquid distribution assembly 13 can not only be used to introduce gas and liquid at different depths of the wastewater, but also rotate with the rotation of the telescopic pipe fitting 18 and can be used as a stirrer.

[0034] In this embodiment, to achieve the transmission between the first driving device 17 and the telescopic pipe fitting 18 and avoid interference with the extraction pipe 24 passing through the center of the top of the telescopic pipe fitting 18, a first bevel gear 39 is provided at the top of the telescopic pipe fitting 18. The first bevel gear 39 meshes with a second bevel gear 41 at one end of a horizontal rotating shaft 40. A third bevel gear 42 at the other end of the horizontal rotating shaft 40 meshes with a fourth bevel gear 43 on the output shaft of the first driving device 17. The first driving device 17 is fixed to the reactor 1, and the first driving device 17 is a motor. It is easy for those skilled in the art to understand that: a belt drive, other gear drive structures or other drive structures in the art can also be used for the transmission between the first driving device 17 and the telescopic pipe fitting 18, as long as interference with the extraction pipe 24 passing through the center of the top of the telescopic pipe fitting 18 can be avoided.

[0035] In this embodiment, the second driving device 20 includes a helical gear ring 47 sleeved on the outer periphery of the telescopic pipe fitting 18. A number of guide rods 48 are provided at the top of the helical gear ring 47. The guide rods 48 pass through the guide holes of the support frame 16. A spring 49 is provided between the helical gear ring 47 and the support frame 16. A fifth bevel gear 50 meshing with the helical gear ring 47 is provided at the end of the roller 21. With this structure, there is no need to install an additional motor on the bracket 19 to drive the roller 21 to rotate. And because installing a motor on the bracket 19 when the bracket 19 rotates will cause technical problems such as a more complex power supply structure and poor circuit sealing. During the process of the first driving device 17 driving the telescopic pipe fitting 18 to rotate and the roller 21 revolving around the telescopic pipe fitting 18, the fifth bevel gear 50 on the roller 21 meshes with the helical gear ring 47 to make the roller 21 rotate. The structure is simple, and when the telescopic pipe fitting 18 expands and contracts, the elastic force of the spring 49 can make the helical gear ring 47 lift and lower, without affecting the transmission of the roller 21.

[0036] To avoid interference between the extraction pipe and the helical gear ring 47, during installation, the extraction pipe 24 bypasses from the bottom of the helical gear ring 47 and is connected to the foam converging area 27 from the side of the foam scraping strip 22.

[0037] In this embodiment, the second input end 7 is further connected to a cleaning water pipeline 44. The reactor 1 includes a third output end 45, and the third output end 45 communicates with the collection tank 46. By connecting the cleaning water pipeline 44 to the second input end 7, it is possible to spray water inside the reactor 1 through the gas-liquid distribution assembly 13 after sewage treatment is completed and discharge the cleaned water to the collection tank 46.

[0038] See Figure 9 , Embodiment 2. The difference between Embodiment 2 and Embodiment 1 lies only in the structure of the second driving device 20. In this embodiment, the second driving device 20 includes a roller driving motor 51 fixed on the bracket 19, and the roller driving motor 51 and the roller 21 are driven by a belt. In this embodiment, during the process that the first driving device 17 drives the telescopic pipe fitting 18 to rotate and the roller 21 revolves around the telescopic pipe fitting 18, the roller 21 is powered by the roller driving motor 51 to make the roller 21 rotate.

[0039] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A DMF wastewater treatment system, characterized in that: It includes a reactor (1), a stripping tower (2), a storage tank (3), a sodium hydroxide solution storage tank (4), and a flocculant storage tank (5); the reactor (1) includes a first input end (6) and a second input end (7), the first input end (6) is communicated with the DMF wastewater outlet (8), the second input end (7) is communicated with the sodium hydroxide solution storage tank (4), the flocculant storage tank (5), and the intake pipeline (10), the reactor (1) includes a first output end (11) and a second output end (12), the first output end (11) is communicated with the storage tank (3), the second output end (12) is communicated with the stripping tower (2), a gas-liquid distribution assembly (13) connected to the second input end (7) and a foam adsorption assembly (14) connected to the first output end (11) are arranged in the reactor (1); the treatment method of the DMF wastewater treatment system includes the following steps: 1) Inject the DMF wastewater into the reactor (1); 2) Heat the DMF wastewater to 30-35 °C, introduce the flocculant, then introduce gas through the intake pipeline (10), and adsorb the foam by the foam adsorption assembly (14) until no more foam is generated; 3) Introduce the sodium hydroxide solution to adjust the pH to 11-12.5, heat the DMF wastewater to 110-135 °C, react for 80-120 minutes to hydrolyze the DMF; 4) Introduce the sodium hydroxide solution to adjust the pH value of the hydrolyzate to 11-12, introduce the hydrolyzate into the stripping tower (2), strip DMA in the stripping tower (2), and the stripped DMA is incinerated and decomposed into nitrogen and carbon dioxide by oxygen-rich air at above 800 °C; 5) Add acid to the stripping residue to neutralize the pH to 6-9 and then discharge it into the biochemical pond.

2. The DMF wastewater treatment system according to claim 1, characterized in that: The storage tank (3) is connected with an absorption tower (15) for adsorbing the tail gas of the storage tank (3).

3. The DMF wastewater treatment system according to claim 1, characterized in that: The DMF wastewater treatment system includes at least two parallel reactors (1).

4. A DMF wastewater treatment system according to claim 1, characterized in that: The foam adsorption assembly (14) includes a support frame (16) fixed in the reactor (1), a telescopic pipe fitting (18) rotatably arranged on the support frame (16) and driven to rotate by a first driving device (17), a bracket (19) extending from the side of the telescopic pipe fitting (18), a roller (21) rotatably arranged on the bracket (19) and driven by a second driving device (20), a foam scraping strip (22) attached to the roller (21) arranged on the bracket (19), a foam accommodation space (23) formed between the foam scraping strip (22) and the surface of the roller (21), a drawing pipe (24) penetrating through the center of the telescopic pipe fitting (18), the end of the drawing pipe (24) is bent and extends into the foam accommodation space (23), the drawing pipe (24) is connected to the storage tank (3), and a negative pressure pump is arranged on the drawing pipe (24).

5. The DMF wastewater treatment system according to claim 4, wherein: The floating foam scraping strip (22) is provided with a convex strip (25) facing the side of the drum (21), and the contact surface of the convex strip (25) matches the arc surface of the outer wall of the drum (21). The top surface of the convex strip (25) forms a floating foam guiding inclined surface (26) that is higher on the side away from the extraction pipe (24) than on the side close to the extraction pipe (24). The convex strip (25) is in close contact with the surface of the drum (21) and forms a floating foam converging area (27) on the suction port side close to the extraction pipe (24). As the drum (21) rotates, the floating foam on the surface of the drum (21) is guided to the floating foam converging area (27).

6. The DMF wastewater treatment system according to claim 4, wherein: The telescopic pipe fitting (18) includes an inner pipe fitting (28) rotatably arranged on the support frame (16) and an outer pipe fitting (29) sleeved on the inner pipe fitting (28) and axially movable. An adjustment motor (30) is arranged on the outer pipe fitting (29). A screw rod (31) is arranged on the output shaft of the adjustment motor (30). A matching block (32) is arranged in the inner pipe fitting (28). The screw rod (31) is in threaded connection with the matching block (32). The support (19) is connected to the outer pipe fitting (29).

7. The DMF wastewater treatment system according to claim 6, characterized in that: A water level sensor (33) is arranged on the outer wall of the telescopic pipe fitting (18), and the water level sensor (33) is electrically connected to the adjustment motor (30).

8. The DMF wastewater treatment system according to claim 4, wherein: The gas-liquid distribution assembly (13) includes a transverse conveying pipe (34) connected to the telescopic pipe fitting (18) and a vertical conveying pipe (35) connected to the transverse conveying pipe (34). The second input end (7) is connected with a vertically arranged guide sleeve (36) located below the rotation center of the telescopic pipe fitting (18). A guide pipe (37) passing through the guide sleeve (36) is arranged at the bottom of the rotation center of the transverse conveying pipe (34). The guide pipe (37) can lift and rotate in the guide sleeve (36). A plurality of one-way nozzles (38) are arranged on the vertical conveying pipe (35).

9. A DMF wastewater treatment system according to any one of claims 4-8, characterized in that: A first helical gear (39) is arranged at the top of the telescopic pipe fitting (18). The first helical gear (39) meshes with a second helical gear (41) at one end of a transverse rotating shaft (40). A third helical gear (42) at the other end of the transverse rotating shaft (40) meshes with a fourth helical gear (43) on the output shaft of the first driving device (17). The first driving device (17) is fixed on the reactor (1).

10. A DMF wastewater treatment system according to any one of claims 4-8, characterized in that: The second driving device (20) includes a helical gear ring (47) sleeved on the outer periphery of the telescopic pipe fitting (18). A plurality of guide rods (48) are arranged at the top of the helical gear ring (47). The guide rods (48) pass through the guide holes of the support frame (16). A spring (49) is arranged between the helical gear ring (47) and the support frame (16). A fifth helical gear (50) meshing with the helical gear ring (47) is arranged at the end of the drum (21).

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