Wastewater treatment device

Abstract

The utility model discloses a wastewater treatment device and belongs to the technical field of battery recovery. The system comprises a high-temperature acidolysis tank, a calcium adding reaction tank, a first filter press, a wastewater adjusting tank, a settling pond unit, a second filter press and a biochemical treatment unit. Discharge wastewater is subjected to acidolysis through a high-temperature acidolysis tank and then added into a calcium-adding reaction tank for a calcium-adding reaction, filtrate obtained by filtering through a first filter press and NMP wastewater are added into a wastewater adjusting tank for homogeneous and average adjustment treatment, and obtained mixed wastewater enters a sedimentation tank unit for calcium removal; and filtering the precipitate by the second filter press to obtain a filtrate, and introducing the filtrate into a biochemical treatment unit for biochemical reaction treatment to obtain a preset liquid. After the liquid is detected to meet the sewage discharge standard, the liquid can be discharged, so that the combined treatment of the discharge wastewater and the NMP wastewater can be realized, the equipment investment is reduced, the treatment cost is reduced, and the industrialization is realized.

Description

Technical Field

[0001] This utility model relates to the field of battery recycling technology, and in particular to a wastewater treatment device. Background Technology

[0002] In recent years, with the rapid development of new energy vehicles, batteries exhibiting bulging or leakage issues are generated during the production and recycling of used lithium batteries. Recycling these batteries requires underwater immersion discharge or other discharge methods before disassembly and crushing can proceed. Because used lithium batteries contain electrolytes, carbonates, organic additives, and film-forming agents, the discharge wastewater generated from battery immersion discharge has a complex composition, containing high concentrations of organic matter, organophosphorus compounds, organofluorine compounds, ammonia nitrogen, and petroleum hydrocarbons. This discharge wastewater needs to undergo certain treatment processes and meet standards before being discharged.

[0003] Meanwhile, the recovery process of the battery additive NMP (N-methylpyrrolidone) will generate NMP wastewater, which contains high concentrations of organic matter and ammonia nitrogen. This NMP wastewater also needs to be treated to meet certain standards before it can be discharged. The two types of wastewater are treated using different equipment, resulting in significant equipment investment and high treatment costs. Utility Model Content

[0004] The purpose of this utility model is to provide a wastewater treatment device to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0005] The technical solution adopted to solve the above-mentioned technical problems is as follows: a wastewater treatment device for treating discharge wastewater and NMP wastewater. The treatment device includes a high-temperature acid hydrolysis tank, a calcium addition reaction tank, a first filter press, a wastewater regulating tank, a sedimentation tank unit, a second filter press, and a biochemical treatment unit connected in sequence. The high-temperature acid hydrolysis tank is used to acid hydrolyze the discharge wastewater into acid hydrolysis wastewater. The calcium addition reaction tank is used to react the acid hydrolysis wastewater into calcium addition wastewater. The first filter press is used to filter the calcium addition wastewater. The wastewater regulating tank is used to mix the NMP wastewater into the calcium addition wastewater filtrate to form mixed wastewater. The sedimentation tank unit is used to react the mixed wastewater into calcium removal wastewater. The second filter press is used to filter the calcium removal wastewater. The biochemical treatment unit is used for the biochemical reaction of the calcium removal wastewater filtrate.

[0006] This technical solution has at least the following beneficial effects: The discharge wastewater is first acidified in a high-temperature acidification tank, then added to a calcium addition reaction tank for calcium addition. Afterward, the precipitate is filtered out by a first filter press. The filtrate from the first filter press and NMP wastewater are added to a wastewater equalization tank for homogenization and quantity adjustment, resulting in mixed wastewater. This mixed wastewater then undergoes calcium removal in a sedimentation tank unit, followed by precipitate filtration by a second filter press. The filtrate from the second filter press is then introduced into a biochemical treatment unit for further biochemical treatment, achieving the desired liquid condition. Once the liquid meets wastewater discharge standards, it can be discharged. Therefore, the combined treatment of discharge wastewater and NMP wastewater can be achieved, reducing equipment investment, lowering treatment costs, and enabling industrialization.

[0007] As a further improvement to the above technical solution, the biochemical treatment unit includes an acid-base adjustment tank, an anaerobic tank, an aerobic tank, and a sedimentation tank arranged sequentially. The filtrate produced by the second filter press is fed into the acid-base adjustment tank to adjust the pH, then fed into the anaerobic tank, then overflows into the aerobic tank for aerobic reaction, and finally overflows into the sedimentation tank for sedimentation treatment. This ensures that the wastewater undergoes a sufficient biochemical reaction.

[0008] As a further improvement to the above technical solution, the anaerobic tank includes an anaerobic hydrolysis acidification tank and a secondary anaerobic reaction tank. The liquid, after its pH has been adjusted in the acid-base adjustment tank, is first introduced into the anaerobic hydrolysis acidification tank for a primary anaerobic reaction, then overflows into the secondary anaerobic reaction tank for a secondary anaerobic reaction, and finally overflows into the aerobic tank. By first introducing the wastewater into the anaerobic hydrolysis acidification tank to hydrolyze lipids to generate alcohols and organic acids, the biodegradability in the secondary anaerobic reaction tank and the aerobic tank is improved. Simultaneously, phosphorus can be released by phosphorus-releasing bacteria in the anaerobic tank.

[0009] As a further improvement to the above technical solution, the calcium addition reaction tank, the sedimentation tank unit, the wastewater conditioning tank, the anaerobic hydrolysis acidification tank, and the secondary anaerobic reaction tank are all equipped with agitators to promote the reaction.

[0010] As a further improvement to the above technical solution, the high-temperature acid hydrolysis tank, the calcium addition reaction tank, the sedimentation tank unit, the anaerobic hydrolysis acidification tank, and the secondary anaerobic reaction tank are all connected to a tail gas treatment device to discharge or treat the generated tail gas.

[0011] As a further improvement to the above technical solution, a portion of the sludge in the sedimentation tank is returned to the anaerobic hydrolysis acidification tank and the secondary anaerobic reaction tank. This allows some of the organisms in the sludge to continue participating in the biochemical reactions in the anaerobic hydrolysis acidification tank and the secondary anaerobic reaction tank.

[0012] As a further improvement to the above technical solution, the sedimentation tank unit includes a first coagulation reaction zone, a second coagulation reaction zone, a third coagulation reaction zone, and an inclined tube sedimentation zone. The mixed wastewater discharged from the wastewater regulating tank sequentially enters the first coagulation reaction zone, the second coagulation reaction zone, and the third coagulation reaction zone for sedimentation and flocculation reactions, and then enters the inclined tube sedimentation zone for mud-water separation. The supernatant after separation enters the second filter press, allowing the wastewater to fully settle and flocculate.

[0013] As a further improvement to the above technical solution, the high-temperature acid hydrolysis tank is equipped with a steam insulation structure for introducing steam to maintain a preset water temperature. Insulation of the high-temperature acid hydrolysis tank by introducing steam provides a stable constant temperature environment for the reaction.

[0014] As a further improvement to the above technical solution, the high-temperature acid hydrolysis tank is covered with insulating cotton to prevent excessive heat dissipation.

[0015] As a further improvement to the above technical solution, a wastewater treatment device further includes a filtrate buffer tank. The filtrate produced by the first filter press is discharged into the filtrate buffer tank for buffering, and the liquid in the filtrate buffer tank is then introduced into the wastewater regulating tank. This improves the stability of the filtrate. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of the structure from the high-temperature acid hydrolysis tank to the filtrate buffer tank in an embodiment of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure from the wastewater regulating tank to the acid-base regulating tank in an embodiment of this utility model;

[0020] Figure 4 This is a schematic diagram of the structure from the anaerobic hydrolysis acidification tank to the sedimentation tank in an embodiment of this utility model;

[0021] Figure 5 This is a schematic diagram of the processing flow of an embodiment of the present utility model.

[0022] 100. High-temperature acidification tank; 200. Calcium addition reaction tank; 300. First filter press; 310. Filtrate buffer tank; 400. Wastewater conditioning tank; 500. Sedimentation tank unit; 510. First coagulation reaction zone; 520. Second coagulation reaction zone; 530. Third coagulation reaction zone; 540. Inclined tube sedimentation zone; 541. Sludge hopper; 542. Inclined tube; 543. Effluent zone; 600. Biochemical treatment unit; 610. Acid-base conditioning tank; 620. Anaerobic tank; 621. Anaerobic hydrolysis acidification tank; 622. Secondary anaerobic reaction tank; 630. Aerobic tank; 640. Sedimentation tank; 700. Discharge tank. Detailed Implementation

[0023] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0024] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0025] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0026] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0027] During the recycling of used lithium batteries, underwater immersion and discharge of the batteries generates discharge wastewater. This wastewater contains high concentrations of organic matter, organophosphates, organofluorine compounds, ammonia nitrogen, and petroleum hydrocarbons; the main pollutants are COD (8000–14000 mg / L) and F. -(200~1200mg / L), TP (1100~1400mg / L), NH3-N (90~350mg / L), petroleum (30~70mg / L).

[0028] NMP (N-methylpyrrolidone) wastewater is generated during the recovery process of the battery additive. NMP wastewater contains high concentrations of organic matter and ammonia nitrogen, meaning that the main pollutants in NMP wastewater are COD (5000-9000 mg / L), NH3-N (100-500 mg / L), and TP (0-10 mg / L).

[0029] Reference Figure 1-5 A wastewater treatment device is available for the combined treatment of discharge wastewater and NMP wastewater. The wastewater treatment device includes a high-temperature acid hydrolysis tank 100, a calcium addition reaction tank 200, a first filter press 300, a filtrate buffer tank 310, a wastewater regulating tank 400, a sedimentation tank unit 500, a biochemical treatment unit 600, and an external discharge tank 700, arranged sequentially.

[0030] The discharge wastewater is discharged into the high-temperature acid hydrolysis tank 100, and 30% dilute sulfuric acid is added to the discharge wastewater at a volume ratio of 6% to 15%. The high-temperature acid hydrolysis tank 100 is equipped with a steam insulation structure, and steam is introduced into the liquid in the high-temperature acid hydrolysis tank 100 to keep the liquid in the high-temperature acid hydrolysis tank 100 at a water temperature between 90 degrees Celsius and 95 degrees Celsius. The high-temperature acid hydrolysis lasts for 6 to 12 hours.

[0031] Because lithium hexafluorophosphate (LiPF6) in discharge wastewater is not very stable, it is easily hydrolyzed into lithium fluoride (LiF) and phosphorus pentafluoride (PF5). Phosphorus pentafluoride is further hydrolyzed into hydrogen fluoride (HF) and phosphorus trifluoride (POF3). POF3 then undergoes further stepwise hydrolysis to generate difluorophosphate (PF2O2). - Difluorophosphate ions further generate fluorophosphate ions (PO3F). 2- Finally, orthophosphate (PO4) is formed. 3- Furthermore, under strongly acidic and high-temperature conditions, the reaction of active hydrogen with lithium hexafluorophosphate causes fluorine to desorb from the anion, thereby breaking the PF bond of lithium hexafluorophosphate to generate PO4. 3- and F - Easily processed inorganic substances.

[0032] The high-temperature acid hydrolysis tank 100 is surrounded by insulation material, which is made of glass wool, to maintain a constant system temperature. A tail gas treatment device is located at the top of the high-temperature acid hydrolysis tank 100. This device is filled with reactive substances such as catalysts. When the tail gas passes through the device, the catalyst reacts chemically with the components of the tail gas that need to be removed, or the adsorbent reacts physically with the components of the tail gas, thus treating the tail gas. The specific type of catalyst or adsorbent is determined based on the actual components of the tail gas that need to be removed.

[0033] The outlet of the high-temperature acidolysis tank 100 is connected to the inlet of the calcium addition reaction tank 200 via a pipeline equipped with a water pump. The acidolysis wastewater formed after acidolysis of the discharge wastewater in the high-temperature acidolysis tank 100 is pumped along the pipeline into the calcium addition reaction tank 200, where a calcium-containing compound, such as calcium hydroxide, calcium oxide, or a mixture thereof, is added. Since calcium ions can react with TP and F... - SO4 2- The reaction produces calcium phosphate, calcium fluoride, and calcium sulfate precipitates. Therefore, 1.5 to 3.0 times the amount of TP and F is added to the reaction zone to completely remove them. - SO4 2- Theoretically, the reaction time for calcium-containing compounds is 1.0 to 2.0 hours. A vertical stirrer is installed on the top of the calcium addition reaction tank 200 to agitate the liquid inside and promote the reaction. A tail gas treatment device is also installed on the top of the calcium addition reaction tank 200. The first gas produced by the reaction inside the calcium addition reaction tank 200 can be discharged through this tail gas treatment device. When the emission of the first gas directly meets the exhaust gas emission standards, the tail gas treatment device can also discharge it directly without any further treatment.

[0034] The inlet of the first filter press 300 is connected to the outlet of the calcium addition reaction tank 200 via a pipeline equipped with a water pump. The calcium-added wastewater, formed after the calcium addition reaction of the acid hydrolysis wastewater in the calcium addition reaction tank 200, enters the first filter press 300 via the pipeline. The first filter press 300 is a plate and frame filter press, which can perform full filtration of the calcium-added wastewater, thereby filtering out the precipitates to obtain the first filtrate. The filtered residue is outsourced for processing.

[0035] The outlet of the first filter press 300 is connected to the inlet of the filtrate buffer tank 310 through a pipe. The first filtrate obtained after the first filter press 300 is discharged into the filtrate buffer tank 310 for buffering.

[0036] The outlet of the filtrate buffer tank 310 is connected to the inlet of the wastewater equalization tank 400 via a pipeline equipped with a water pump. The first filtrate in the filtrate buffer tank 310 is pumped into the wastewater equalization tank 400. The wastewater equalization tank 400 is equipped with a wastewater inlet, through which NMP wastewater is added, thereby mixing the NMP wastewater with the first filtrate. After homogenization and quantity equalization, a mixed wastewater is obtained. The volume of the NMP wastewater is 1 to 2 times the volume of the discharge wastewater.

[0037] The sedimentation tank unit 500 includes a first coagulation reaction zone 510, a second coagulation reaction zone 520, a third coagulation reaction zone 530, and an inclined tube sedimentation zone 540. The inclined tube sedimentation zone 540 includes a sludge hopper 541, an inclined tube 542, and an effluent zone 543. The sedimentation tank unit 500 is used for integrated calcium removal of mixed wastewater.

[0038] Specifically, the outlet of the wastewater regulating tank 400 is connected to the inlet of the first coagulation reaction zone 510 via a pipeline equipped with a water pump. The mixed wastewater in the wastewater regulating tank 400 is pumped into the first coagulation reaction zone 510, and 1.5 to 3.0 times the theoretical value of industrial-grade sodium carbonate for removing calcium ions is added to the first coagulation reaction zone 510, thereby causing carbonate ions to react with calcium ions to form calcium carbonate precipitate. The reaction time is 1.0 to 2.0 hours. After the reaction, the mixed wastewater is sequentially treated with polyaluminum chloride (PAC) in the second coagulation reaction zone 520 and polyacrylamide (PAM) in the third coagulation reaction zone 530 for flocculation reaction. Then, it flows through an overflow weir into the sludge hopper 541 of the inclined tube sedimentation zone 540. The flocculated sediment settles to the bottom along the inclined tube 542, thereby achieving sludge-water separation. The supernatant after separation overflows into the effluent zone 543 for buffering, thus realizing the calcium removal reaction of the mixed wastewater. A stirrer is installed on the top of the wastewater equalization tank 400 to promote the mixing of the two types of wastewater.

[0039] In the sedimentation tank unit 500, the first coagulation reaction zone 510, the second coagulation reaction zone 520, and the third coagulation reaction zone 530 are each equipped with a stirrer to promote the reaction. The first coagulation reaction zone 510, the second coagulation reaction zone 520, and the third coagulation reaction zone 530 are each equipped with an exhaust gas treatment device.

[0040] The outlet of effluent zone 543 is connected to the inlet of the second filter press via a pipeline equipped with a water pump. The supernatant from the calcium removal process in effluent zone 543 is filtered by the second filter press to obtain the second filtrate, and the filtered sludge cake is transported off-site.

[0041] The biochemical treatment unit 600 is used for the biochemical reaction of the second filtrate. Specifically, the biochemical treatment unit 600 includes an acid-base adjustment tank 610, an anaerobic tank 620, an aerobic tank 630, and a sedimentation tank 640 arranged in sequence. The anaerobic tank 620 includes an anaerobic hydrolysis acidification tank 621 and a secondary anaerobic reaction tank.

[0042] The outlet of the second filter press is connected to the inlet of the acid-base adjustment tank 610 via a pipe equipped with a water pump. The second filtrate filtered by the second filter press is pumped into the acid-base adjustment tank 610, where 30% sulfuric acid is added to adjust the pH to between 6.5 and 8.5 to meet the conditions for biochemical reaction.

[0043] In other embodiments, the filtration work of the second filter press can be undertaken by the first filter press 300, reducing the number of filter presses required. The first filter press 300 can filter the calcium-added wastewater and the calcium-removed supernatant simultaneously or in batches. That is, after flocculation, the wastewater overflows into the sludge hopper 541 to achieve sludge-water separation. The supernatant from the sludge hopper 541 is pumped into the first filter press 300 for filtration treatment and then pumped back to the effluent zone 543 for buffering. The outlet of the effluent zone 543 is connected to the inlet of the acid-base adjustment tank 610 through a pipeline equipped with a water pump.

[0044] The outlet of the acid-base adjustment tank 610 is connected to the inlet of the anaerobic hydrolysis acidification tank 621 via a pipeline equipped with a water pump. Wastewater with the adjusted pH in the acid-base adjustment tank 610 enters the anaerobic hydrolysis acidification tank 621 via the pump. The dissolved oxygen concentration is controlled to be less than 0.1 mg / L, the sludge age to be 6 days, the hydraulic retention time to be 4 to 5 hours, and the ORP to be less than -300 mV. This controls the anaerobic biological reaction at the hydrolysis and acidification stages. Anaerobic and acidifying bacteria hydrolyze esters in the wastewater to produce alcohols and organic acids, thus breaking down large, difficult-to-biodegrade molecules into easily biodegradable small molecules, improving biodegradability. Simultaneously, phosphorus is released by phosphorus-releasing bacteria in the anaerobic tank.

[0045] Wastewater from anaerobic hydrolysis acidification tank 621 overflows into secondary anaerobic reactor 622. By controlling dissolved oxygen concentration (0.2–0.4 mg / L), water temperature (20–35℃), and pH (7.0–8.5), the maximum specific growth rate of nitrite-oxidizing bacteria is increased compared to that of nitrate-oxidizing bacteria, thus controlling most of the NO2. - and a small amount of NO3 - It is reduced to nitrogen gas, thereby achieving rapid removal of ammonia nitrogen through short-cut nitrification-denitrification.

[0046] Wastewater overflowing from the secondary anaerobic reactor 622 is transferred to the aerobic reactor 630. The dissolved oxygen concentration is controlled at 2–3 mg / L. 30Under conditions of 30-50% concentration, MLSS of 3000-5000 mg / L, and pH of 7-8, organic matter is degraded, nitrified, deammoniated, and phosphorus is removed by aerobic bacteria.

[0047] Wastewater overflowing from aerobic tank 630 flows into sedimentation tank 640 for sedimentation treatment. Part of the remaining sludge from sedimentation tank 640 is returned to anaerobic hydrolysis acidification tank 621 and secondary anaerobic reaction tank 622, while another part enters a screw press dewatering machine for dewatering treatment. The supernatant enters discharge tank 700, where it is determined whether the effluent meets the Class III standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996). If it meets the standard, it is discharged; otherwise, it is returned to high-temperature acidification tank 100 for further treatment.

[0048] Both the anaerobic hydrolysis acidification tank 621 and the secondary anaerobic reaction tank 622 are equipped with agitators at the bottom to promote the biochemical reactions of the solutions within. Both the anaerobic hydrolysis acidification tank 621 and the secondary anaerobic reaction tank 622 are equipped with sealing covers and exhaust gas treatment devices at the top. The aerobic tank 630 is equipped with aeration pipes for aeration.

[0049] The processing procedure of the processing device in this application embodiment includes the following steps:

[0050] 1. The discharge wastewater is collected in a high-temperature acidification tank 100. 6-15% (by volume) of 30% dilute sulfuric acid is added, and steam is introduced to maintain the water temperature at 90-95°C. High-temperature acidification is carried out for 6-12 hours, thus converting the discharge wastewater into acidified wastewater. The tail gas treatment device at the top of the high-temperature acidification tank 100 is used to discharge the tail gas, and catalysts or adsorbents required for tail gas treatment are selectively set according to emission standards.

[0051] 2. The acidification wastewater after high-temperature acidification enters the calcium addition reactor 200, and 1.5 to 3.0 times the amount of TP and F are added to the calcium addition reactor 200 to remove them. - SO4 2- Theoretically, the reaction time for calcium hydroxide is 1.0 h to 2.0 h. The calcium-added wastewater formed after the acidolysis reaction has the following properties: COD ≤ 12000, NH3-N ≤ 37 mg / L, TP ≤ 16, and F... - ≤20, SO4 2- ≤4000mg / L, petroleum hydrocarbons ≤1mg / L, Ca 2+ ≤600mg / L. The stirrer at the top of the calcium addition reaction tank 200 can promote the calcium addition reaction. The tail gas treatment device at the top of the calcium addition reaction tank 200 is used to discharge tail gas, and the catalyst or adsorbent required for tail gas treatment can be selectively set according to the emission standards.

[0052] 3. The calcium-added wastewater after the calcium addition reaction enters the first filter press 300 for filtration. The filter cake is transported off-site for disposal, and the resulting first filtrate (calcium-added wastewater filtrate) enters the filtrate buffer tank 310 for buffering.

[0053] 4. The first filtrate (calcium-added wastewater filtrate) enters the wastewater equalization tank 400, and then 1-2 times the volume of the discharge wastewater (NMP wastewater) is added for wastewater homogenization and quantity equalization. The homogenized mixed wastewater should have the following properties: COD ≤ 10000 mg / L, NH3-N ≤ 346 mg / L, TP ≤ 13 mg / L, and F... - ≤10mg / L, Ca 2+ ≤300mg / L. The agitator on top of the wastewater equalization tank 400 can promote the homogenization and equalization of wastewater.

[0054] 5. The homogenized and conditioned mixed wastewater enters sedimentation tank unit 500 for calcium removal. The calcium-removed wastewater contains Ca... 2+ ≤40mg / L. The mixed wastewater first enters the first coagulation reaction zone 510 to react with the added sodium carbonate for 1.0 to 2.0 hours. PAC and PAM are added to the second and third coagulation reaction zones respectively, followed by thorough sludge flocculation and sedimentation. The flocculated wastewater overflows into the inclined tube sedimentation zone 540, and the sludge is deposited in the sludge hopper 541 and then pumped into the second filter press for filtration. The supernatant (filtrate from calcium-removed wastewater) overflows into the effluent zone 543.

[0055] 6. The supernatant formed in the effluent zone 543 after the calcium removal reaction enters the biological treatment unit for further treatment. Specifically, the supernatant enters the pH adjustment tank 610, where 30% sulfuric acid is added to adjust the wastewater pH to 6-8. The pH-adjusted wastewater then sequentially enters the anaerobic hydrolysis acidification tank 621, the secondary anaerobic reaction tank 622, and the aerobic tank 630. This process hydrolyzes large, difficult-to-biodegrade molecules into easily biodegradable small molecules, improving biodegradability. Simultaneously, phosphorus is released by phosphorus-releasing bacteria in the anaerobic tank; most of NO2- and a small amount of NO3- are reduced to nitrogen gas, thus achieving rapid ammonia nitrogen removal through short-cut nitrification-denitrification. Aerobic bacteria degrade organic matter, nitrify to remove ammonia, and remove phosphorus. The resulting biologically treated effluent has COD ≤ 200 mg / L, NH3-N ≤ 10 mg / L, and TP ≤ 1 mg / L.

[0056] 7. The wastewater after COD removal in the aerobic tank 630 enters the sedimentation tank 640. The bottom of the sedimentation tank is equipped with a cone bucket for sludge collection. Part of the sludge is returned to the anaerobic hydrolysis acidification tank 621 and the secondary anaerobic reaction tank 622, and the rest is treated by pressure filtration.

[0057] 8. The supernatant from sedimentation tank 640 is discharged into discharge tank 700. The effluent is tested to see if it meets the Class III standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996). If it meets the standard, it is discharged; if it does not meet the standard, it is returned to the high-temperature acid hydrolysis tank 100 for further treatment.

[0058] This application adopts a "high-temperature acid hydrolysis + calcium treatment" method, which first breaks the PF bonds in the electrolyte into inorganic substances such as phosphate and fluoride ions, and then adds calcium ions to remove phosphorus and fluoride, solving the industry problem that the traditional direct calcium addition method is difficult to remove organic phosphorus and organic fluoride from electrolyte wastewater; at the same time, the high-temperature stage can promote the degradation and volatilization of ammonia nitrogen in wastewater, reducing the load of biochemical ammonia nitrogen removal.

[0059] Furthermore, the combined treatment of discharge wastewater and NMP wastewater can effectively reduce equipment investment and achieve synergistic wastewater treatment. The biochemical system controls the anaerobic reaction during the hydrolysis and acidification stages, which can effectively hydrolyze lipid organic matter in the wastewater into alcohols and organic acids, facilitating the degradation of organic matter by bacteria in the aerobic tank.

[0060] The process flow of this application is "high temperature acid hydrolysis + calcium treatment + biochemical treatment". The design is concise, the treatment is efficient, and the effluent can meet the Class III standard of "Integrated Wastewater Discharge Standard" (GB8978-1996).

[0061] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A wastewater treatment device, characterized in that, The treatment device for treating discharge wastewater and NMP wastewater includes a high-temperature acid hydrolysis tank (100), a calcium addition reaction tank (200), a first filter press (300), a wastewater regulating tank (400), a sedimentation tank unit (500), a second filter press, and a biochemical treatment unit (600) connected in sequence. The high-temperature acid hydrolysis tank (100) is used to acid hydrolyze the discharge wastewater into acid hydrolysis wastewater. The calcium addition reaction tank (200) is used to react the acid hydrolysis wastewater into calcium addition wastewater. The first filter press (300) is used to filter the calcium addition wastewater. The wastewater regulating tank (400) is used to mix the NMP wastewater into the calcium addition wastewater filtrate to form mixed wastewater. The sedimentation tank unit (500) is used to react the mixed wastewater into calcium removal wastewater. The second filter press is used to filter the calcium removal wastewater. The biochemical treatment unit (600) is used for the biochemical reaction of the calcium removal wastewater filtrate.

2. The wastewater treatment device according to claim 1, characterized in that: The biochemical treatment unit (600) includes an acid-base adjustment tank (610), an anaerobic tank (620), an aerobic tank (630), and a sedimentation tank (640) arranged in sequence. The filtrate produced by the second filter press is fed into the acid-base adjustment tank (610) to adjust the pH, then fed into the anaerobic tank (620) for anaerobic reaction, then overflows into the aerobic tank (630) for aerobic reaction, and then overflows into the sedimentation tank (640).

3. The wastewater treatment device according to claim 2, characterized in that: The anaerobic tank (620) includes an anaerobic hydrolysis acidification tank (621) and a secondary anaerobic reaction tank (622). The liquid in the acid-base adjustment tank (610) after adjusting the pH is first introduced into the anaerobic hydrolysis acidification tank (621) for a primary anaerobic reaction, then overflows into the secondary anaerobic reaction tank (622) for a secondary anaerobic reaction, and then overflows into the aerobic tank (630).

4. The wastewater treatment device according to claim 3, characterized in that: The calcium addition reaction tank (200), the sedimentation tank unit (500), the wastewater regulating tank (400), the anaerobic hydrolysis acidification tank (621), and the secondary anaerobic reaction tank (622) are all equipped with a stirrer.

5. The wastewater treatment device according to claim 3, characterized in that: The high-temperature acid hydrolysis tank (100), the calcium addition reaction tank (200), the sedimentation tank unit (500), the anaerobic hydrolysis acidification tank (621), and the secondary anaerobic reaction tank (622) are all connected to a tail gas treatment device.

6. The wastewater treatment device according to claim 3, characterized in that: A portion of the sludge in the sedimentation tank (640) is returned to the anaerobic hydrolysis acidification tank (621) and the secondary anaerobic reaction tank (622).

7. The wastewater treatment device according to claim 1, characterized in that: The sedimentation tank unit (500) includes a first coagulation reaction zone (510), a second coagulation reaction zone (520), a third coagulation reaction zone (530), and an inclined tube sedimentation zone (540). The mixed wastewater discharged from the wastewater regulating tank (400) enters the first coagulation reaction zone (510), the second coagulation reaction zone (520), and the third coagulation reaction zone (530) in sequence for sedimentation and flocculation reactions, and then enters the inclined tube sedimentation zone (540) for mud-water separation. The supernatant after separation enters the second filter press.

8. The wastewater treatment device according to claim 1, characterized in that: The high-temperature acid hydrolysis tank (100) is equipped with a steam insulation structure for introducing steam to maintain a preset water temperature.

9. A wastewater treatment device according to claim 1 or 8, characterized in that: The high-temperature acid hydrolysis tank (100) is covered with insulating cotton.

10. The wastewater treatment device according to claim 1, characterized in that: It also includes a filtrate buffer tank (310), into which the filtrate produced by the first filter press (300) is discharged and buffered, and the liquid in the filtrate buffer tank (310) is then introduced into the wastewater regulating tank (400).

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