Power battery structural member production wastewater treatment method

Abstract

The invention discloses a power battery structural member production wastewater treatment method, which is used for treating power battery structural member production cleaning wastewater, and sequentially comprises the following steps: performing oil separation on the power battery structural member production cleaning wastewater through an oil separation tank, and adjusting the power battery structural member production cleaning wastewater in a cleaning water adjusting tank; lower-layer water regulated by the cleaning water regulating tank enters a membrane treatment system through a middle tank for membrane treatment, upper-layer water enters a petroleum water treatment system for treatment, and water phases of air floatation equipment and a three-phase separator of the petroleum water treatment system return to the cleaning water regulating tank to participate in regulation; clear liquid treated by the membrane treatment system enters a clear water tank if reaching the standard, enters a biochemical treatment system for biochemical treatment if not reaching the standard, concentrated liquid flows back to the middle tank, and the concentrated liquid in the middle tank is discharged into a petroleum water treatment system; and clean water treated by the biochemical treatment system enters cleaning water. Effective treatment of the power battery structural member production wastewater is realized.

Description

Technical Field

[0001] The present invention relates to the field of environmental water treatment, and in particular to a method for treating wastewater produced by power battery structural parts. Background Art

[0002] In recent years, new energy vehicles have developed rapidly, including pure electric vehicles, extended-range electric vehicles, hybrid vehicles, fuel cell electric vehicles, hydrogen engine vehicles and other new energy vehicles. Among them, pure electric vehicle technology is the most mature, its prospects are widely optimistic, and it is recognized as the most likely to replace traditional vehicles. The most core component of pure electric vehicles is the power battery. Its specific capacity, safety performance, production cost, etc. are the key factors that determine whether pure electric vehicles can be widely promoted and used. However, power batteries will generate a large amount of production wastewater during the manufacturing process. Among them, the water quality of the production wastewater of power battery structural parts is relatively complex.

[0003] With the acceleration of the industrialization process of power batteries, the amount of production wastewater of power battery structural parts, especially cleaning wastewater, is increasing, and the environmental risks to the ecological environment and human health are becoming more and more serious. However, there is no effective solution for power battery structural parts production wastewater at home and abroad. The existing treatment scheme for power battery structural parts production wastewater is: the cleaning wastewater is separated by oil in the oil separator and then enters the cleaning water regulating tank for regulation and then enters the intermediate tank for sedimentation. The water coming out of the intermediate tank enters the traditional biochemical treatment system for biochemical treatment, and then enters the clear water tank, the sludge enters the biochemical sludge tank, and then is sent to the plate and frame filter press for filtration. The mud cake is used as solid waste, and the filtrate returns to the biochemical system for further treatment.

[0004] The water quality in the clear water tank after treatment by the existing treatment scheme for wastewater from the production of power battery structural parts cannot meet the standards and needs further treatment before it can be discharged in compliance with the standards.

[0005] Finding an effective solution to wastewater from the production of power battery structural parts has become an urgent issue that needs to be addressed in the industry. Summary of the invention

[0006] Based on the above problems, the present invention provides a method for treating wastewater from the production of power battery structural parts, aiming to improve at least one of the problems mentioned in the background technology.

[0007] The technical solution is: a method for treating wastewater from the production of power battery structural parts, which treats wastewater from the production of power battery structural parts and includes the following steps in sequence:

[0008] The cleaning wastewater from the production of power battery structural parts is separated by oil in the oil separator and then enters the cleaning water regulating tank for regulation;

[0009] The lower layer of water after adjustment in the cleaning water regulating tank enters the membrane treatment system through the intermediate tank for membrane treatment, and the upper layer of water enters the petroleum water treatment system for treatment. The flotation equipment of the petroleum water treatment system and the water phase of the three-phase separator return to the cleaning water regulating tank for adjustment;

[0010] The clear liquid treated by the membrane treatment system will enter the clear water tank if it meets the standards, and will enter the biochemical treatment system for biochemical treatment if it does not meet the standards. The concentrated liquid will flow back to the intermediate tank, and the concentrated liquid in the intermediate tank will be discharged into the petroleum water treatment system;

[0011] The clean water treated by the biochemical treatment system enters the cleaning water.

[0012] Optionally, the power battery structural member is a component for protecting the interior of the power battery, including a battery shell, a battery cover, a battery bottom plate and metal accessories.

[0013] Optionally, the power battery structural component production wastewater is power battery structural component production cleaning wastewater

[0014] Optionally, the membrane treatment system includes: a primary membrane pool, a primary membrane water production tank, a secondary membrane pool, a secondary membrane water production tank, a tertiary membrane pool and a tertiary membrane water production tank, which are arranged in sequence according to the treatment order.

[0015] Optionally, the reflux ratio of the concentrate after treatment in the primary membrane pool>the reflux ratio of the concentrate after treatment in the secondary membrane pool>the reflux ratio of the concentrate after treatment in the tertiary membrane pool.

[0016] Optionally, the reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0017] Optionally, the biochemical treatment system includes, arranged in order of treatment: at least one anaerobic tank, a first sedimentation tank, an anoxic tank, at least one aerobic tank, a medium sedimentation tank and a second sedimentation tank.

[0018] Optionally, the power battery structural component production wastewater treatment system also includes a biochemical sludge treatment system, and the biochemical sludge treatment system includes: a biochemical sludge pool, a biochemical filter press and a sludge temporary storage room, which are arranged in a treatment order.

[0019] Optionally, the filtrate produced by the biochemical filter press is returned to the cleaning water regulating tank for regulation.

[0020] Invention principle and beneficial effects:

[0021] The inventor team found in the treatment of power battery structural parts production wastewater that the water quality after treatment by the existing power battery structural parts production wastewater treatment scheme needs further treatment because the particularity of power battery structural parts production wastewater is not taken into account. The water quality of power battery structural parts production wastewater is basically as shown in Table 1 (the data in Table 1 comes from the power battery structural parts production cleaning wastewater that enters the cleaning water regulating tank after oil separation in the oil separator without adding liquid, only adjusting the water volume and balancing the water quality) :

[0022] Table 1 Water quality of raw water from power battery structural parts production wastewater

[0023]

[0024] As can be seen from Table 1, the main pollutants in the wastewater from the production of power battery structural parts are relatively high, and the contents of COD, BOD, SS, and petroleum are much higher than those in ordinary wastewater. The BOD / COD ratio is <0.3, and the conductivity is also relatively high, making it difficult to treat.

[0025] The present invention arranges a three-stage membrane treatment system in front of a biochemical treatment system, and follows the principle that the reflux ratio of concentrated liquid after treatment in the first-stage membrane pool is greater than the reflux ratio of concentrated liquid after treatment in the second-stage membrane pool and greater than the reflux ratio of concentrated liquid after treatment in the third-stage membrane pool. The water phase separated by a three-phase separator and the water phase separated by an air flotation device are returned to a cleaning water regulating tank, and the upper oil-water layer of the cleaning water regulating tank, the concentrated liquid in the middle tank, and the water layer of the physicochemical sludge tank are sent to the air flotation device. Through dynamic separation by the air flotation device and static separation by the three-phase separator, the power battery structural parts production cleaning wastewater can be treated into dischargeable wastewater without adding external liquid medicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the treatment process flow of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0029] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or connected in one piece; it can be directly connected, or indirectly connected through an intermediate medium, or it can be internally connected between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, power battery structural parts refer to components that protect the interior of the power battery, including battery shells, battery covers, battery bottom plates and metal accessories.

[0031] In the present invention, power battery structural component production wastewater refers to power battery structural component production cleaning wastewater.

[0032] Please refer to Figure 1 An embodiment of the present invention provides a power battery structural component production wastewater treatment system, including: a grease trap, a cleaning water regulating tank, an intermediate tank, a membrane treatment system and a clear water tank, which are arranged in the treatment order.

[0033] Furthermore, the membrane treatment system includes: a primary membrane pool, a primary membrane water production tank, a secondary membrane pool, a secondary membrane water production tank, a tertiary membrane pool and a tertiary membrane water production tank, which are arranged in sequence according to the treatment order.

[0034] Furthermore, the membrane installed in the primary membrane pool is a tubular membrane, and the membranes installed in the secondary and tertiary membrane pools are nanofiltration membranes.

[0035] Furthermore, the power battery structural parts production wastewater treatment system also includes a petroleum water treatment system, which treats the upper oil and water in the cleaning water regulating tank and the concentrated liquid formed in the middle tank during operation. The petroleum water treatment system includes: flotation equipment, three-phase separator and oil collection box arranged in the order of treatment. The flotation equipment dynamically separates to form three phases (oil phase, water phase and mud phase from top to bottom), and the three-phase separator statically separates the oil phase from the flotation equipment to form three phases (oil phase, water phase and mud phase from top to bottom). The petroleum water treatment system also includes: a physicochemical sludge pool and a physicochemical filter press arranged in the order of treatment. The physicochemical sludge pool is used to treat the sludge discharged from the flotation equipment and the three-phase separator. The mud cake of the physicochemical filter press and the oil in the oil collection box are transported out as hazardous waste.

[0036] Furthermore, in order to achieve a better treatment effect, the first pipeline and the second pipeline arranged in parallel are connected between the air flotation device and the cleaning water regulating tank, the three-phase separator is connected to the third pipeline, the other end of the third pipeline is connected to the first pipeline, the physicochemical sludge tank is also connected to the fifth pipeline and the sixth pipeline, the other end of the sixth pipeline is connected to the physicochemical filter press, the intermediate tank is connected to the seventh pipeline, the other end of the seventh pipeline is connected to the second pipeline, and the other end of the fifth pipeline is connected to the seventh pipeline. The first pipeline and the third pipeline return the water phase separated by the three-phase separator and the water phase separated by the air flotation device to the cleaning water regulating tank, the second pipeline, the fifth pipeline, and the seventh pipeline send the upper oil and water of the cleaning water regulating tank, the concentrated liquid of the intermediate tank, and the water layer of the physicochemical sludge tank to the air flotation device, and the sixth pipeline returns the filtrate of the physicochemical filter press to the physicochemical sludge tank.

[0037] In the present invention, the process of forming the concentrated liquid in the intermediate tank is as follows: water from the intermediate water layer is transported from the cleaning water regulating tank to the intermediate tank to a certain liquid level, and then the water in the intermediate tank is transported to the membrane treatment system for treatment. Water with a certain liquid level in the intermediate tank is retained in the intermediate tank. After the membrane treatment system has completed the treatment, water from the intermediate water layer is transported from the cleaning water regulating tank to the intermediate tank to the same liquid level, and then the water in the intermediate tank is transported to the membrane treatment system for treatment. Water with a certain liquid level at the bottom of the intermediate tank is retained in the intermediate tank. Water with the same liquid level in the intermediate tank is retained in the intermediate tank. The next cycle is performed according to this operation mode. After multiple operations, the liquid remaining in the intermediate tank is the concentrated liquid.

[0038] Furthermore, in order to achieve better treatment effects, the intermediate pool is also connected to a fourth pipeline, the other end of the fourth pipeline is connected to the primary membrane pool, the primary membrane water production tank is connected to an eighth pipeline, the other end of the eighth pipeline is connected to the secondary membrane pool, the secondary membrane water production tank is connected to a ninth pipeline, and the other end of the ninth pipeline is connected to the tertiary membrane pool; the fourth pipeline returns the concentrate of the primary membrane pool to the intermediate pool, the eighth pipeline returns the concentrate of the secondary membrane pool to the primary membrane water production tank, and the ninth pipeline returns the concentrate of the tertiary membrane pool to the secondary membrane water production tank.

[0039] Furthermore, in order to achieve better treatment effects, the proportion of the concentrate refluxed from the fourth, eighth and ninth pipelines to the concentrate produced at this stage gradually decreases. Furthermore, the fourth pipeline returns all the concentrate from the first membrane pool to the middle pool, the eighth pipeline returns 40% of the concentrate from the second membrane pool to the first membrane water production tank, and the ninth pipeline returns 20% of the concentrate from the third membrane pool to the second membrane water production tank.

[0040] Furthermore, the membrane treatment system also includes a cleaning system, which is respectively connected to the primary membrane pool, the secondary membrane pool and the tertiary membrane pool. The cleaning system is used to be turned on when the primary membrane pool, the secondary membrane pool and the tertiary membrane pool are not working, to clean the membranes in the primary membrane pool, the secondary membrane pool and the tertiary membrane pool.

[0041] The present invention sets up a three-stage membrane treatment system, and follows the principle that the reflux ratio of concentrated liquid after treatment in the first-stage membrane pool is greater than the reflux ratio of concentrated liquid after treatment in the second-stage membrane pool and greater than the reflux ratio of concentrated liquid after treatment in the third-stage membrane pool. The water phase separated by the three-phase separator and the water phase separated by the flotation device are returned to the cleaning water regulating tank, and the upper oil-water layer of the cleaning water regulating tank, the concentrated liquid in the middle tank, and the water layer of the physicochemical sludge tank are sent to the flotation device. Through dynamic separation by the flotation device + static separation by the three-phase separator, the power battery structural parts production cleaning wastewater can be treated into dischargeable wastewater without adding external liquid medicine.

[0042] Furthermore, when the raw water quality of the power battery structural parts production cleaning wastewater deteriorates, the treated wastewater does not meet the standards and cannot enter the clean water tank. The power battery structural parts production wastewater treatment system also includes a biochemical treatment system and a biochemical sludge treatment system. The biochemical treatment system is located between the membrane treatment system and the clean water tank, and the biochemical sludge treatment system is located after the membrane treatment system and is used to treat the biochemical sludge discharged from the biochemical sludge treatment system.

[0043] Furthermore, the biochemical treatment system includes, arranged in order of treatment: at least one anaerobic tank, a first sedimentation tank, an anoxic tank, at least one aerobic tank, a medium sedimentation tank and a second sedimentation tank.

[0044] Furthermore, the biochemical sludge treatment system includes: a biochemical sludge pool, a biochemical filter press and a sludge temporary storage room, which are arranged in a treatment order. The sludge in the sludge temporary storage room is transported out for treatment as solid waste.

[0045] The method for treating wastewater produced by power battery structural parts provided in an embodiment of the present invention adopts the wastewater treatment system for producing wastewater produced by power battery structural parts provided in an embodiment of the present invention for treatment.

[0046] In the following Examples 1 to 3 and Comparative Examples 1 to 6, the equipment size of the power battery structural parts production wastewater treatment system is 240m 3 / d Design of raw water treatment capacity for power battery structural parts production cleaning wastewater, technical personnel in this field can design it according to needs.

[0047] In the following Examples 1 to 3 and Comparative Examples 1 to 6, the number of anaerobic tanks in the biochemical treatment system is 2, which are a primary UASB anaerobic tank and a secondary UASB anaerobic tank, the number of aerobic tanks is 6, and the 6 aerobic tanks are arranged in sequence, and the second sedimentation tank is an inclined tube sedimentation tank.

[0048] Example 1

[0049] In this embodiment, in the power battery structural parts production wastewater treatment system of the present invention, the biochemical treatment system is not turned on, the membrane treatment system and the petroleum water treatment system are turned on, the water quality of the treatment object is as shown in Table 2, and the water quality of the three-stage membrane water production tank is as shown in Table 2.

[0050] In this embodiment, the reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0051] Comparative Example 1

[0052] Compared with Example 1, this Comparative Example 1 is the same as Example 1 except that the water quality of the treatment object is deteriorated.

[0053] The reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0054] The water quality of the treatment object is shown in Table 2, and the water quality of the tertiary membrane water production tank is shown in Table 2.

[0055] Example 2

[0056] This embodiment is carried out on the basis of Comparative Example 1 (i.e. including Comparative Example 1). When Comparative Example 1 detects that the water quality of the tertiary membrane water production tank does not meet the discharge standard, the biochemical treatment system is turned on to carry out biochemical treatment.

[0057] The effluent quality of the biochemical treatment system is shown in Table 2.

[0058] Comparative Example 2

[0059] In this comparative example, in the power battery structural component production wastewater treatment system of the present invention, the membrane treatment system is turned off, and the biochemical treatment system and the petroleum water treatment system are turned on. The water quality of the treatment object is the same as that in Example 1.

[0060] The effluent quality of the biochemical treatment system is shown in Table 2.

[0061] Comparative Example 3

[0062] The water quality of the treatment object in Comparative Example 3 is the same as that in Example 1, except that the reflux ratio of the concentrate after treatment in the primary membrane pool is 50%, the reflux ratio of the concentrate after treatment in the secondary membrane pool is 50%, and the reflux ratio of the concentrate after treatment in the tertiary membrane pool is 50%.

[0063] The water quality of the tertiary membrane water production tank is shown in Table 2.

[0064] Comparative Example 4

[0065] In Comparative Example 4, the water quality of the treatment object is the same as that of Example 2, except that the membrane treatment system and the biochemical treatment system are turned on, and the petroleum water treatment system is not turned on.

[0066] The reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0067] The effluent quality of the biochemical treatment system is shown in Table 2.

[0068] Comparative Example 5

[0069] In Comparative Example 5, the water quality of the treatment object is the same as that of Example 2, and the membrane treatment system, the biochemical treatment system and the petroleum water treatment system are all turned on. The difference is that in the petroleum water treatment system, the three-phase separator is not turned on.

[0070] The reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0071] The effluent quality of the biochemical treatment system is shown in Table 2.

[0072] Comparative Example 6

[0073] In Comparative Example 6, the water quality of the treatment object is the same as that of Example 2, and the membrane treatment system, the biochemical treatment system and the petroleum water treatment system are all turned on. The difference is that in the petroleum water treatment system, the flotation equipment is not turned on.

[0074] The reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0075] The effluent quality of the biochemical treatment system is shown in Table 2.

[0076] Example 3

[0077] In Example 3, the water quality of the treatment object is the same as that in Example 2, and the membrane treatment system, the biochemical treatment system and the petroleum water treatment system are also turned on. The difference is that the biochemical filter press is connected to the tenth pipeline, and the other end of the tenth pipeline is connected to the cleaning water regulating tank. The tenth pipeline returns the filtrate of the biochemical filter press to the cleaning water regulating tank.

[0078] The reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

[0079] The effluent quality of the biochemical treatment system is shown in Table 2.

[0080] Table 2

[0081]

[0082] It can be seen from Table 2 that in Example 1, when the water quality of the power battery structural parts production wastewater treated is not too bad, the biochemical treatment system is not turned on and the water quality of the tertiary membrane water production tank can be discharged into the clear water tank.

[0083] However, in comparative example 1 where the water quality is relatively poor, the water quality of the tertiary membrane water production tank does not meet the standards and cannot be discharged into the clean water tank.

[0084] In Example 2, the water in the three-stage membrane water production tank of Comparative Example 1 is treated by a biochemical treatment system and can be sent to the clean water tank to meet the standards.

[0085] In Comparative Example 2, the treated water quality is the same as that in Example 1 (the water quality is not too bad), but because it is not treated by the membrane treatment system and directly enters the biochemical system for treatment, the effluent quality after the biochemical system treatment does not meet the standards and cannot be discharged into the clean water tank.

[0086] Comparative Example 3 is compared with Example 1 (water quality is not too bad). Under the same water quality conditions, the concentrate reflux ratio of each level is the same. The water quality of the three-stage membrane water production tank does not meet the discharge standard and cannot be discharged into the clear water tank.

[0087] Compared with Example 2 (poor water quality), under the same water quality conditions, since the petroleum water treatment system was not turned on, the water quality from the biochemical treatment system did not meet the discharge standards and could not be discharged into the clean water tank.

[0088] Compared with Example 2, under the same water quality conditions, although the petroleum water treatment system was turned on, the static three-phase separator in the petroleum water treatment system was not turned on, and the water quality coming out of the biochemical treatment system did not meet the discharge standards and could not be discharged into the clear water tank.

[0089] Compared with Example 2, under the same water quality conditions, although the petroleum water treatment system was turned on, the water quality from the biochemical treatment system did not meet the discharge standards and could not be discharged into the clean water tank because the flotation equipment for phase separation in the petroleum water treatment system was not turned on.

[0090] Compared with Example 2, under the same water quality conditions, Example 3 has a better treatment effect than Example 2 because the filtrate of the biochemical filter press is returned to the cleaning water regulating tank.

[0091] In the present invention, unless otherwise specified, all are prior art.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for treating wastewater from the production of power battery structural parts, which is used to treat wastewater from the production of power battery structural parts, characterized in that: The following steps are included in sequence: The cleaning wastewater from the production of power battery structural parts is separated by oil in the oil separator and then enters the cleaning water regulating tank for regulation; The lower layer of water after adjustment in the cleaning water regulating tank enters the membrane treatment system through the intermediate tank for membrane treatment, and the upper layer of water enters the petroleum water treatment system for treatment. The flotation equipment of the petroleum water treatment system and the water phase of the three-phase separator return to the cleaning water regulating tank for adjustment; The clear liquid treated by the membrane treatment system will enter the clear water tank if it meets the standards, and will enter the biochemical treatment system for biochemical treatment if it does not meet the standards. The concentrated liquid will flow back to the intermediate tank, and the concentrated liquid in the intermediate tank will be discharged into the petroleum water treatment system; The clean water treated by the biochemical treatment system enters the cleaning water.

2. The method for treating wastewater from the production of power battery structural parts according to claim 1, characterized in that: The power battery structural parts are components for protecting the interior of the power battery, including a battery shell, a battery cover, a battery bottom plate and metal accessories.

3. The method for treating wastewater from production of power battery structural parts according to claim 1, characterized in that: The power battery structural component production wastewater is power battery structural component production cleaning wastewater.

4. The method for treating wastewater produced by the production of power battery structural parts according to claim 1 is characterized in that the membrane treatment system includes: a primary membrane pool, a primary membrane water production tank, a secondary membrane pool, a secondary membrane water production tank, a tertiary membrane pool and a tertiary membrane water production tank, which are arranged in the order of treatment.

5. The method for treating wastewater from the production of power battery structural parts according to claim 4 is characterized in that the reflux ratio of the concentrated solution after treatment in the primary membrane pool is greater than the reflux ratio of the concentrated solution after treatment in the secondary membrane pool and greater than the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool.

6. The method for treating wastewater from the production of power battery structural parts according to claim 5 is characterized in that the reflux ratio of the concentrated solution after treatment in the primary membrane pool is 100%, the reflux ratio of the concentrated solution after treatment in the secondary membrane pool is 40%, and the reflux ratio of the concentrated solution after treatment in the tertiary membrane pool is 20%.

7. The method for treating wastewater produced by power battery structural parts according to claim 1 is characterized in that the biochemical treatment system includes: at least one anaerobic tank, a first sedimentation tank, an anoxic tank, at least one aerobic tank, a medium sedimentation tank and a second sedimentation tank, which are arranged in the order of treatment.

8. The method for treating wastewater produced by power battery structural parts according to claim 7 is characterized in that the wastewater treatment system for power battery structural parts production also includes a biochemical sludge treatment system, and the biochemical sludge treatment system includes: a biochemical sludge pool, a biochemical filter press and a sludge temporary storage room, which are arranged in sequence according to the treatment order.

9. The method for treating wastewater from the production of power battery structural parts according to claim 8, characterized in that the filtrate produced by the biochemical filter press is returned to the cleaning water regulating tank for regulation.

10. The method for treating wastewater produced by power battery structural parts according to claim 8 is characterized in that the membrane installed in the primary membrane pool is a tubular membrane, the secondary membrane pool and the tertiary membrane pool are both installed with nanofiltration membranes, the number of anaerobic tanks is 2, which are a primary UASB anaerobic tank and a secondary UASB anaerobic tank, the number of aerobic tanks is 6, and the 6 aerobic tanks are arranged in sequence, and the second sedimentation tank is an inclined tube sedimentation tank.

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