Balanced flow immersed membrane filtration device and method
By configuring a parallel micro-nano filtration unit in the immersed membrane filtration process and using reverse gas washing and chemical cleaning systems, the problem of overall replacement of the filter membrane after damage is solved, achieving continuous production operation and efficient utilization of resources.
Patent Information
- Application Number
- CN202311756768.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-19
- Publication Date
- 2025-06-20
AI Technical Summary
The existing immersion membrane filtration process has the problem of waste, high cleaning costs and inability to ensure continuous production operation after the filter membrane is damaged.
The balanced flow immersion membrane filtration device is adopted, and at least two micro-nano filtration units are arranged in parallel. Each unit is connected to a reverse air washing mechanism, a suction pump and a chemical cleaning system. By designing the number of micro-nano filtration units, the chemical cleaning and production of the spare unit can be alternated to ensure continuous operation.
It effectively avoids waste caused by filter membrane replacement, reduces chemical cleaning costs, realizes continuous production operation, and improves the operating efficiency of membrane modules.
Smart Images
Figure CN120169165A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an oily wastewater treatment process, and specifically to an immersed membrane filtration process. Background Art
[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
[0003] At present, the oily wastewater treatment process at home and abroad requires that the water quality after treatment meet the "5.1.1" index (oil content ≤5mg / L, suspended solids content ≤1mg / L, median suspended solids particle size ≤1μm). Conventional filtration technology cannot meet the demand, and micro-nano membrane component filtration technology is used as terminal treatment.
[0004] The submerged membrane filtration process sets the area of the filter membrane according to the membrane flux and the amount of water to be treated, and then sets up a container corresponding to the area of the filter membrane. The micro-nano membrane component corresponding to the area of the filter membrane is installed in this container. Obviously, if the amount of water to be treated required by production is large, the corresponding filter membrane area and container also need to be increased year by year to form a large filtration unit. Such a process setting has the following problems. First, as long as the filter membrane is damaged in one place, although the other parts are still in good condition, the filtration performance of the membrane no longer meets the requirements and can only be replaced as a whole, resulting in unnecessary waste. Second, because the filter membrane area is large, the container (such as a cement pool) where the micro-nano membrane assembly is located is also correspondingly large. When cleaning is required, if in-situ cleaning is desired, a large amount of chemical agents must be added to the cement pool to meet the cleaning agent concentration, resulting in excessively high cleaning costs. Therefore, the membrane is generally disassembled and immersed in a separately set membrane cleaning pool for chemical cleaning. At least the production needs to be terminated during the membrane disassembly and assembly process, and continuous production cannot be guaranteed. Third, in the past, the submerged membrane assembly was only equipped with a forward air washing function, the start and stop time of the suction pump was manually set, the liquid level of the membrane system was difficult to control, overflow often occurred, and the membrane system had low operating efficiency.
[0005] In addition, the start and stop time of the suction pump in the current submerged membrane filtration process is set manually, and the liquid level is difficult to control.
[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may contain information that does not constitute prior art. Summary of the invention
[0007] In view of this, the present disclosure provides a balanced flow submerged membrane filtration device to solve the problems that the current submerged membrane filtration process is only equipped with one micro-nano filtration unit, resulting in waste in cleaning and replacement of the filtration membrane and failure to ensure continuous operation of production.
[0008] In addition, the present disclosure also provides a balanced flow submerged membrane filtration method.
[0009] In a first aspect, the balanced flow submerged membrane filtration device includes: A membrane filtration system and a chemical cleaning system; The membrane filtration system includes at least two micro-nano filtration units connected in parallel; Each of the micro-nano filtration units is respectively connected to a reverse air washing mechanism, a suction pump, and the chemical cleaning system.
[0010] In the present disclosure and possible embodiments, the micro-nano filtration unit includes 1 micro-nano membrane module or N micro-nano membrane modules connected in parallel; The micro-nano membrane modules are respectively connected to the reverse air washing mechanism, the suction pump, and the chemical cleaning system.
[0011] In the present disclosure and possible embodiments, the micro-nano membrane module uses a polyvinylidene fluoride membrane, and the filtration accuracy of the polyvinylidene fluoride membrane is configured to be 50 nm - 100 nm; and / or, An aeration head is arranged inside the micro-nano membrane module and is connected to the forward air washing mechanism through a forward air washing inlet pipe at the lower part, and the forward air washing mechanism includes a forward air washing air compressor; and / or, A drain pipe is arranged at the lower part of the micro-nano membrane module, and the concentrated water at the bottom of the micro-nano membrane module is discharged through the drain pipe; and / or, The water outlet pipe of the micro-nano membrane module is connected to the suction pump, and the filtration water of the micro-nano membrane module is discharged by using the suction pump.
[0012] In the present disclosure and possible embodiments, the specification of the reaction column in the micro-nano membrane module is configured to be Ф300 mm - Ф1000 mm.
[0013] In the present disclosure and possible embodiments, the reverse air washing mechanism includes a reverse air washing air compressor; The reverse air washing air compressor is connected to the micro-nano filtration unit through a reverse air washing valve.
[0014] In the present disclosure and possible embodiments, the chemical cleaning system includes a first chemical cleaning device and a second chemical cleaning device; two chemical agents are added to the micro-nano filtration unit through the first chemical cleaning device and the second chemical cleaning device.
[0015] In the present disclosure and possible embodiments, the micro-nano filtration unit is connected to a balance water tank through a pipeline, and the liquid level height of the balance water tank is the same as the liquid level height of the micro-nano filtration unit.
[0016] In a second aspect, the balanced flow submerged membrane filtration method includes: Sewage treatment is carried out using the submerged membrane filtration device described in the first aspect.
[0017] In the present disclosure and possible embodiments, the number of the micro-nano filtration units for determining the effective filtration area and the standby filtration area respectively for meeting the production filtration requirements is determined While the micro-nano filtration units corresponding to the effective filtration area are in production, chemical cleaning is performed on the micro-nano filtration units corresponding to the standby filtration area for a set time; When the set time ends, the micro-nano filtration units that have undergone the chemical cleaning are put into production, and at the same time, the corresponding number of micro-nano filtration units in production are replaced and put into chemical cleaning until all the initially produced micro-nano filtration units have undergone chemical cleaning; then, each round of cleaning and production is carried out in the same way in a cycle.
[0018] In the present disclosure and possible embodiments, each of the micro-nano filtration units is respectively connected to a reverse air washing mechanism, a suction pump, and a chemical cleaning system.
[0019] The balanced flow submerged membrane filtration device and method of the present disclosure configure the membrane filtration system into micro-nano filtration units with a small area and a large number. When the filter membrane of one filtration unit is damaged, only the filter membrane with a small area needs to be replaced, effectively avoiding the waste caused by membrane replacement in the past; at the same time, by designing the number of micro-nano filtration units, while ensuring a certain number of micro-nano filtration units are in production, chemical cleaning is performed on the standby number of micro-nano filtration units. In this way, not only can the number of micro-nano filtration units put into normal production be always guaranteed, but also the quality of the micro-nano filtration units put into production can be guaranteed, so as to complete production with both quality and quantity, and at the same time, continuous operation of production is realized; furthermore, a reverse air washing mechanism is also provided. Through the coordinated cooperation of the reverse air washing mechanism and the forward air washing, the increase in the transmembrane pressure difference is greatly delayed while ensuring the constant operation flux of the membrane module, effectively solving the problem of the short chemical cleaning cycle caused by insufficient driving force of the membrane module; in addition, each set of micro-nano filtration units is an independent unit and operates in parallel, which is easy for membrane module cleaning, replacement, and addition, greatly facilitating operation management. Continuing to perform chemical in-situ cleaning on each micro-nano filtration unit in sequence and ensuring that the overall filtration process does not stop and continuous water production; further, while ensuring the chemical cleaning concentration, the production of chemical cleaning concentrated water is greatly reduced, and the problems that the start-stop time of the suction pump in the current submerged membrane filtration process is artificially set and the liquid level is not easy to control are effectively solved; at the same time, when the membrane module is immersed in a large-volume water tank, the chemical off-line cleaning operation is complex and continuous production cannot be guaranteed, and the dosage of chemical in-situ cleaning agents is large, etc. While greatly facilitating production management, the operation efficiency of the membrane module is improved. Description of the Drawings
[0020] The above and other objects, features, and advantages of the present disclosure will become clearer from the following description of the embodiments of the present disclosure with reference to the accompanying drawings. In the drawings: Figure 1 It is a schematic diagram of the balanced flow immersion membrane filtration device according to an embodiment of the present disclosure; Figure 2 It is a parallel connection structure diagram of three micro-nano filtration units according to an embodiment of the present disclosure; Figure 3 It is a schematic diagram of the membrane module structure according to an embodiment of the present disclosure.
[0021] In the figure: 1. Balanced water tank; 2. Micro-nano filtration unit inlet valve; 3. Chemical cleaning inlet valve of the micro-nano filtration unit; 4. Micro-nano filtration membrane module; 5. Vent valve; 6. Forward air washing valve; 7. Micro-nano filtration unit; 8. Reverse air washing valve; 9. Micro-nano filtration unit outlet valve; 10. Negative pressure gauge; 11. Suction pump; 12. Flow meter; 13. Product water tank; 14. Concentrate water tank; 15. Product water external transfer pump; 16. Concentrate water external transfer pump; 17. First chemical cleaning device; 18. Second chemical cleaning device; 19. Forward air washing air compressor; 20. Reverse air washing air compressor; A and B respectively represent the chemical cleaning inlet and outlet; C and D respectively represent the forward air washing inlet and reverse air washing inlet; 4-1. Reaction column; 4-2. Aeration head; 4-3. Outlet pipe; 4-4. Forward air washing inlet pipe; 4-5. Vent pipe; 4-6. Chemical cleaning outlet liquid pipe; 4-7. Inlet pipe. Embodiment
[0022] The following describes the present disclosure based on embodiments. However, it should be noted that the present disclosure is not limited to these embodiments. In the following detailed description of the present disclosure, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.
[0023] In addition, those of ordinary skill in the art should understand that the provided drawings are only for illustrating the objects, features, and advantages of the present disclosure, and the drawings are not actually drawn to scale. The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. And the terms "connection" and "coupling" used in this application, unless otherwise specified, both include direct and indirect connection (coupling). In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, should not be construed as a limitation to this application.
[0024] Meanwhile, unless the context clearly requires otherwise, words such as "comprising", "including" and the like throughout the specification and claims shall be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is to say, it is the meaning of "including but not limited to".
[0025] Figure 1 is a schematic diagram of the balanced-flow immersed membrane filtration device according to an embodiment of the present disclosure; as Figure 1 shown, the balanced-flow immersed membrane filtration device includes a membrane filtration system and a chemical cleaning system, wherein the membrane filtration system includes three micro-nano filtration units 7 connected in parallel; each micro-nano filtration unit is respectively connected to a reverse air washing mechanism and a suction pump.
[0026] Of course, for the convenience of description, this embodiment takes three micro-nano filtration units 7 as an example for illustration. In actual applications, the number of the micro-nano filtration units 7 is usually more, such as up to dozens. The specific number is jointly determined by the effective filtration area and the spare filtration area that meet the production filtration requirements. For the number of micro-nano filtration units 7 corresponding to the effective filtration area, specifically, the conventional techniques in the art are used to determine the membrane flux and the effective filtration area of the filtration membrane to be filtered according to the water quality characteristics, water production requirements, etc., and the unit filtration area of the micro-nano filtration unit 7 is set. The total filtration area obtained by adding the effective filtration area and the spare filtration area is divided by the unit filtration area to obtain the number of micro-nano filtration units 7 required.
[0027] Because in the case of meeting the same filtration requirements, the membrane filtration system of this embodiment splits the original one filtration unit into several units. Correspondingly, the area of the filtration membrane of each unit is very small. When the filtration membrane is damaged, it is convenient to replace and waste is avoided; in addition, for each micro-nano filtration unit 7, the specification of the container to be configured is also correspondingly reduced a lot. When performing chemical cleaning, the amount of chemical agents to be added to the container is also reduced proportionally. Therefore, in-situ cleaning of the membrane can be realized.
[0028] As Figure 1 and Figure 2 shown, the micro-nano filtration unit 7 of the embodiment of the present disclosure is composed of two micro-nano membrane components 4 connected in parallel. On the one hand, the parallel body of the two micro-nano membrane components 4 is connected to a reverse air washing air compressor 20 through a reverse air washing valve 8, and on the other hand, it is connected to a suction pump 11 through a micro-nano filtration unit water outlet valve 9; of course, the number of micro-nano membrane components 4 in the micro-nano filtration unit 7 can be 1 or more; preferably, the micro-nano filtration unit water outlet valve 9 is an electric valve.
[0029] As Figure 1 and Figure 2As shown, the micro-nano membrane module 4 of the embodiments of the present disclosure preferably uses a reinforced polyvinylidene fluoride (PVDF) membrane, and the filtration accuracy of the PVDF membrane is preferably configured to be 50 nm - 100 nm.
[0030] As Figures 1 - 3 shown, an aeration head 4-2 is arranged inside each micro-nano membrane module 4. The micro-nano membrane module 4 is respectively connected to a reverse air washing air compressor 20 and a suction pump 11 through a water outlet pipe 4-3. The suction pump 11 is used to pump out the filtered water of the micro-nano membrane module 4 and send it into a water production tank 13, and the water production tank 13 is connected to a water production external transmission pump 15 to output the filtered water.
[0031] In Figure 1 this, the reverse air washing mechanism of the embodiments of the present disclosure includes a reverse air washing air compressor 20, and the reverse air washing air compressor is connected to a micro-nano filtration unit 7 through a reverse air washing valve 8; of course, this embodiment does not limit that the reverse air washing mechanism uses the reverse air washing air compressor 20, and as long as other devices that can provide an air washing function can also be used; preferably, the reverse air washing valve 8 is an electric valve.
[0032] As Figure 1 and 2 shown, the embodiments of the present disclosure use the reverse air washing air compressor 20 to perform reverse air washing on the filter membrane in the micro-nano membrane module 4. At the same time, the lower part of the micro-nano membrane module 4 is connected to a forward air washing mechanism through a forward air washing inlet pipe 4-4 and a forward air washing inlet valve 6. The forward air washing mechanism of this embodiment uses a forward air washing air compressor 19 to perform forward air washing on the filter membrane in the micro-nano membrane module 4. Of course, this embodiment does not limit that the forward air washing mechanism uses the forward air washing air compressor 19, and as long as other devices that can provide an air washing function can also be used. Therefore, in the immersed membrane filtration device of this embodiment, each micro-nano filtration unit 7 is provided with forward air washing and reverse air washing. By alternately operating the two, without changing the operating flux of the membrane module, the increase of the transmembrane pressure difference is greatly delayed, and the problem of insufficient driving force existing in the immersed membrane filtration process due to its own process characteristics and short chemical cleaning cycle is solved.
[0033] A drain pipe 4-5 is arranged at the lower part of the micro-nano membrane module 4, and a drain valve 5 is arranged on the drain pipe 4-5. The concentrated water at the bottom of the micro-nano membrane module 4 enters a concentrated water tank 14 through the drain pipe 4-5 and the drain valve 5. The concentrated water tank 14 is connected to a concentrated water external transmission pump 16, and the concentrated water in the concentrated water tank 14 is discharged through the concentrated water external transmission pump 16. In addition, the micro-nano membrane module 4 is provided with a water inlet pipe 4-7 and a chemical cleaning liquid outlet pipe 4-6.
[0034] As Figure 1As shown, the micro-nano filtration unit 7 of the embodiment of the present disclosure is connected to a chemical cleaning system. The chemical cleaning system of this embodiment is provided with a first chemical cleaning device 17 and a second chemical cleaning device 18 with exactly the same structure. The first chemical cleaning device 17 is used to add sodium hypochlorite, and the second chemical cleaning device 18 is used to add citric acid. The chemical cleaning outlet A of the chemical cleaning device is docked with the water inlet pipe 4-7 of the micro-nano membrane module 4 through the micro-nano filtration unit chemical cleaning inlet valve 3, that is, the water inlet pipe 4-7 is also the chemical cleaning liquid inlet pipe of the micro-nano membrane module 4. The micro-nano membrane module 4 is additionally provided with a chemical cleaning liquid outlet pipe 4-6 docked with the chemical cleaning inlet B of the chemical cleaning device. The pipeline layout height of the chemical cleaning liquid outlet pipe 4-6 must be higher than the filtration membrane, and then it flows back to the chemical cleaning device by self-flow through the pipeline for circulating chemical cleaning. Among them, the chemical cleaning device includes a circulation pump and a chemical agent container. The circulation pump is used to input the chemical agent in the chemical cleaning agent container into the micro-nano membrane module 4 to achieve the purpose of circulating chemical cleaning of the filtration membrane therein.
[0035] In Figure 1 this embodiment, the embodiment of the present disclosure connects the water inlet pipe 4-7 of the micro-nano membrane module 4 through the balance water tank 1 by using the micro-nano filtration unit water inlet valve 2. The liquid level height of the balance water tank 1 is the same as the liquid level height of the micro-nano membrane module 4. The bottom is provided with a water outlet pipe. Therefore, according to the principle of communicating vessels, without considering other influencing factors, the liquid levels of the balance water tank 1 and the micro-nano membrane module 4 have the same height, and the liquid level height of the micro-nano membrane module 4 changes with the change of the liquid level of the balance water tank 1. Preferably, the balance water tank 1 is provided with a high liquid level G, a working liquid level H, a low liquid level D, and is interlocked with the balance water tank inlet electric valve and the pumping and washing pump 11. The interlocking control mechanism can be commercially purchased, and the embodiment of the present disclosure does not limit it. By controlling the liquid level of the balance water tank 1, it is ensured that all groups of micro-nano membrane modules 4 are completely immersed in water, improving the operation efficiency of the membrane module. Preferably, the water inlet of the balance water tank 1 uses an electric valve, and the water inlet electric valve and the suction pump 11 are controlled to work through the liquid level of the balance water tank 1. When the balance water tank 1 is at the low liquid level, the front-end water inlet electric valve is opened, and the suction pump 11 stops working. When the liquid level of the balance water tank 1 reaches the high liquid level, the front-end water inlet electric valve is closed. A working liquid level is set between the high liquid level and the low liquid level. When the liquid level reaches the set working liquid level, the suction pump 11 is started without waiting to reach the high liquid level.
[0036] The membrane filtration system of the embodiment of the present disclosure is preferably connected to an automatic control mechanism, such as a PLC control system. Correspondingly, various valves in this embodiment are also configured as electric valves, and the electric valves cooperate with the automatic control mechanism to automatically control the production process and the filtration membrane cleaning process of the membrane filtration system.
[0037] At the same time, this embodiment further illustrates the method of using the balanced flow submerged membrane filtration device of the present invention to perform submerged membrane filtration on sewage, and the core of the method is: First, the number of micro-nano filtration units 7 with effective filtration area and spare filtration area respectively used to meet the production filtration requirements is determined, so as to determine the scale of the membrane filtration system in the device; in the process of filtration, while the micro-nano filtration units 7 with a corresponding number of effective filtration areas are in production, the micro-nano filtration units 7 with a corresponding number of spare filtration areas are chemically cleaned or physically reversed air-washed for a set time; when the set time is over, the micro-nano filtration units 7 that have been chemically cleaned or physically reversed air-washed are put into production, and at the same time, the corresponding number of micro-nano filtration units 7 in production are replaced for chemical cleaning or physical reverse air-washing; continue to replace the micro-nano filtration units 7 that have not been chemically cleaned or physically reversed air-washed for cleaning in the same way, until all the micro-nano filtration units 7 in the membrane filtration system are cleaned, and then restart the next round in the same way, control the micro-nano filtration units 7 in the membrane filtration system to switch between production and chemical cleaning or physical reverse air-washing, and repeat the cycle to achieve timely cleaning of the filtration membrane while ensuring continuous operation of production.
[0038] The balanced flow submerged membrane filtration method of this embodiment performs timed cleaning on a spare number of micro-nano filtration units 7 before putting them into use. This can not only ensure the number of micro-nano filtration units 7 put into normal production at all times, but also ensure the quality of the micro-nano filtration units 7 put into production, thereby completing the production with both quality and quantity and ensuring the continuous operation of production.
[0039] Taking the membrane filtration system of this embodiment including three micro-nano filtration units 7 as an example, the PLC control system is used to automatically control the filtration process. The specific control process is: setting the cleaning time, setting one micro-nano filtration unit 7 in the cleaning state while the other two micro-nano filtration units 7 are in the production state; when the set cleaning time is over, the cleaned micro-nano filtration unit 7 is put into production, and one of the two micro-nano filtration units 7 in the original production state is put into cleaning, and when the set cleaning time is over again, the other micro-nano filtration unit 7 in the original production state is cleaned. At this point, all three micro-nano filtration units 7 are cleaned, and then this process is repeated.
[0040] The balanced flow submerged membrane filtration device and method of the present invention increases the chemical backwash cycle by more than 8 times under the condition that the same process and operating parameters are used at the front end of the membrane, greatly reducing the output of chemical cleaning concentrated water and the dosage of chemical cleaning agents, while effectively solving the problem of high cost of adding chemical agents during in-situ cleaning of traditional submerged membrane components. With the same water production, the power consumption is only about 15% of that of the existing external membrane process.
[0041] The above-described embodiments are only illustrative of the implementation manners of the present disclosure. Although the description is relatively specific and detailed, it should not be construed as a limitation on the scope of the present disclosure patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications, equivalent substitutions, improvements, etc. can be made, and these all fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.
Claims
1. A balanced-flow submerged membrane filtration device, characterized in that, Comprising: A membrane filtration system and a chemical cleaning system; The membrane filtration system includes at least two micro-nano filtration units (7) connected in parallel; Each of the micro-nano filtration units (7) is respectively connected to a reverse air washing mechanism, a suction pump (11), and the chemical cleaning system.
2. The balanced-flow submerged membrane filtration device according to claim 1, characterized in that: The micro-nano filtration unit (7) includes 1 micro-nano membrane module (4) or N micro-nano membrane modules (4) connected in parallel; The micro-nano membrane modules (4) are respectively connected to the reverse air washing mechanism, the suction pump (11), and the chemical cleaning system.
3. The balanced-flow submerged membrane filtration device according to claim 2, characterized in that: The micro-nano membrane module (4) uses a polyvinylidene fluoride membrane, and the filtration accuracy of the polyvinylidene fluoride membrane is configured to be 50 nm - 100 nm; and / or, An air diffuser (4-2) is arranged inside the micro-nano membrane module (4) and is connected to a forward air washing mechanism through a forward air washing inlet pipe (4-4) at the lower part, and the forward air washing mechanism includes a forward air washing air compressor (19); and / or, A drain pipe (4-5) is arranged at the lower part of the micro-nano membrane module (4), and the concentrated water at the bottom of the micro-nano membrane module (4) is discharged through the drain pipe (4-5); and / or, The water outlet pipe (4-3) of the micro-nano membrane module (4) is connected to the suction pump (11), and the suction pump (11) is used to discharge the filtered water of the micro-nano membrane module (4).
4. The balanced-flow submerged membrane filtration device according to claim 3, characterized in that: The specification of the reaction column (4-1) in the micro-nano membrane module (4) is configured to be Ф300 mm - Ф1000 mm.
5. The balanced-flow submerged membrane filtration device according to any one of claims 1-4, characterized in that: The reverse air washing mechanism includes a reverse air washing air compressor (20); The reverse air washing air compressor (20) is connected to the micro-nano filtration unit (7) through a reverse air washing valve (8).
6. The balanced-flow submerged membrane filtration device according to claim 5, characterized in that: The chemical cleaning system includes a first chemical cleaning device (17) and a second chemical cleaning device (18); two chemical agents are added to the micro-nano filtration unit (7) through the first chemical cleaning device (17) and the second chemical cleaning device (18).
7. The balanced-flow submerged membrane filtration device according to any one of claims 1-4 or claim 6, characterized in that: The micro-nano filtration unit (7) is connected to a balance water tank (1) through a pipeline, and the liquid level height of the balance water tank (1) is the same as that of the micro-nano filtration unit (7).
8. A balanced-flow submerged membrane filtration method, characterized in that, Comprising: Using the submerged membrane filtration device according to any one of claims 1-7 for sewage treatment.
9. The balanced-flow submerged membrane filtration method according to claim 8, characterized in that: Determining the number of the micro-nano filtration units (7) respectively used to meet the effective filtration area and the spare filtration area for production filtration requirements While the micro-nano filtration units (7) corresponding to the effective filtration area are in production, the micro-nano filtration units (7) corresponding to the spare filtration area are subjected to chemical cleaning for a set time; When the set time ends, the micro-nano filtration units (7) that have undergone chemical cleaning are put into production, and at the same time, the corresponding number of micro-nano filtration units (7) in production are replaced and put into chemical cleaning until all the initially produced micro-nano filtration units (7) have undergone chemical cleaning; then each round of cleaning and production is carried out in the same way in a cycle.
10. The balanced-flow submerged membrane filtration method according to claim 9, characterized in that: Each of the micro-nano filtration units (7) is respectively connected to a reverse air washing mechanism, a suction pump (11), and the chemical cleaning system.