Method and system for reverse osmosis concentrate backwashing ultrafiltration device

Abstract

The present application relates to a kind of method and system using reverse osmosis concentrated water backwashing ultrafiltration device, belong to power plant water treatment technical field, the method includes the following steps: obtaining clean water station water, and sequentially carry out ultrafiltration treatment and reverse osmosis treatment obtain primary reverse osmosis concentrated water;Obtain the water quality data of primary reverse osmosis concentrated water;Determine the langley correction term of primary reverse osmosis concentrated water, obtain the langley index of primary reverse osmosis concentrated water based on the langley correction term and water quality data;Formulate control level based on langley index;According to control level, determine to use primary reverse osmosis concentrated water or ultrafiltration device production water to backwash ultrafiltration device.The present application introduces langley correction term, comprehensively considers temperature correction term, supersaturation correction term and dynamic correction term and multiple factors, can more comprehensively, accurately reflect the water quality characteristics of primary reverse osmosis concentrated water, especially its scaling and corrosion tendency.

Description

Technical Field

[0001] This invention relates to a method and system for backwashing an ultrafiltration device using reverse osmosis concentrate, belonging to the field of power plant water treatment technology. Background Technology

[0002] In the field of water treatment in power plants, with the increasing demands for efficient water resource utilization and higher water purity, traditional pre-desalination processes generally combine ultrafiltration and reverse osmosis modules. The ultrafiltration module primarily uses physical sieving to intercept suspended solids, colloids, and other impurities in the water, reducing turbidity and providing qualified feed water for the subsequent reverse osmosis module. The reverse osmosis module utilizes a semi-permeable membrane to separate salts, ions, and other impurities under pressure, producing desalinated pure water for use as boiler feedwater in power plants. However, existing technologies have significant limitations in the backwashing stage of ultrafiltration units. During long-term operation, impurities gradually accumulate on the surface of the ultrafiltration membrane, leading to a decline in filtration performance. To restore the filtration performance of the ultrafiltration membrane, regular backwashing of the ultrafiltration unit is necessary. Traditional backwashing methods mostly use ultrafiltration permeate, resulting in water waste; while using primary reverse osmosis concentrate for ultrafiltration backwashing can improve water utilization, an effective evaluation and utilization system is currently lacking.

[0003] Existing technologies, such as the Chinese utility model patent application CN204462762U, disclose a control system based on a concentrated water reverse osmosis recovery device. This system includes: a main control MCU, multiple variable pressure pumps, a reverse osmosis system, a water quality detection module, a water quality data collection and processing module, and a memory. The variable pressure control output of the main control MCU is connected to the multiple variable pressure pumps, the output of the multiple variable pressure pumps is connected to the reverse osmosis system, the output of the reverse osmosis system is connected to the water quality detection module, the water quality detection module is connected to the data collection and processing module, and the output of the data collection and processing module is connected to the water quality data feedback terminal of the main control MCU. However, this patent does not consider the influence of the water quality characteristics of the backwash water on the backwash effect and ultrafiltration membrane performance, and cannot perform targeted backwash control based on the scaling and corrosion tendencies of different water qualities. The control method is relatively passive, mainly relying on preset time intervals and fixed programs for backwashing operations, and cannot make proactive adjustments based on real-time water quality changes. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes a method and system for backwashing an ultrafiltration device using reverse osmosis concentrate.

[0005] The technical solution of the present invention is as follows: On one hand, the present invention provides a method for backwashing an ultrafiltration device using reverse osmosis concentrate, characterized by comprising the following steps: Water from the water purification station is obtained and then subjected to ultrafiltration and reverse osmosis treatments in sequence to obtain primary reverse osmosis concentrate. Obtain water quality data of the first-stage reverse osmosis concentrate; determine the Langrier correction term of the first-stage reverse osmosis concentrate; and obtain the Langrier index of the first-stage reverse osmosis concentrate based on the Langrier correction term and the water quality data. Control levels are determined based on the Langerile index; Based on the control level, determine whether to use primary reverse osmosis concentrate or ultrafiltration permeate to backwash the ultrafiltration unit.

[0006] Preferably, the Langerell correction term for the first-stage reverse osmosis concentrate includes a temperature correction term, a supersaturation correction term, and a kinetic correction term, specifically: The Langerier correction term is obtained by summing the temperature correction term, the supersaturation correction term, and the kinetic correction term.

[0007] Preferably, the Langerell index includes the pH value of the first-stage reverse osmosis concentrate, the pH value of the first-stage reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate, and a Langerell correction term, specifically: The Langerier index is obtained by adding the difference between the pH value of the first-stage reverse osmosis concentrate and the pH value of the first-stage reverse osmosis concentrate when calcium carbonate is saturated at the operating temperature.

[0008] Preferably, the pH value of the primary reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate is obtained based on the water quality data of the primary reverse osmosis concentrate.

[0009] Preferably, the steps for determining the control level based on the Langerhans index are as follows: Obtain the ion product of calcium sulfate, magnesium carbonate, and barium sulfate in the first-stage reverse osmosis concentrate; If the Langerel index and , , If so, then the control level is set to low; If the Langerel index and , , If so, then set the control level to medium; Otherwise, set the control level to high; In the formula, This represents the ion product of calcium sulfate. This represents the solubility product of calcium sulfate. This represents the ion product of magnesium carbonate. This represents the solubility product of magnesium carbonate. This represents the ion product of barium sulfate. This represents the solubility product of barium sulfate.

[0010] Preferably, if the control level is low, an ultrafiltration backwash security filter with a precision of 100 microns is used to filter the first-stage reverse osmosis concentrate, and the ultrafiltration unit is backwashed. If the control level is medium, use an ultrafiltration backwash security filter with an accuracy of 50 / 20 microns to filter the first-stage reverse osmosis concentrate and backwash the ultrafiltration unit. If the control level is high, an ultrafiltration backwash security filter with a precision of 100 microns is used to filter the water produced by the ultrafiltration unit, and the ultrafiltration unit is backwashed.

[0011] In another aspect, the present invention also provides a system for backwashing an ultrafiltration device using reverse osmosis concentrate, including an ultrafiltration module, a reverse osmosis module, a water quality detection module, a control module, and a backwashing module; The ultrafiltration module is used to process the water coming from the water purification station; The reverse osmosis module is used to process the water produced by the ultrafiltration unit and to produce primary reverse osmosis permeate and primary reverse osmosis concentrate, wherein the primary reverse osmosis permeate enters the subsequent desalination system. The water quality detection module is used to obtain water quality data of the first-stage reverse osmosis concentrate. The control module is used to set the control level and, based on the control level, control the backwash module to backwash the ultrafiltration unit using primary reverse osmosis concentrate or ultrafiltration unit permeate.

[0012] The present invention has the following beneficial effects: 1. This invention determines whether the concentrated water from the first-stage reverse osmosis unit is suitable for backwashing of the ultrafiltration unit by reasonably evaluating its water quality characteristics. This avoids the waste of water resources caused by using ultrafiltration permeate or pure water for backwashing in traditional backwashing methods, realizes the recycling of water resources, and improves the utilization rate of water resources.

[0013] 2. This invention introduces a Langerell correction term, comprehensively considering multiple factors such as temperature correction, supersaturation correction, and kinetic correction. This allows for a more comprehensive and accurate reflection of the water quality characteristics of the first-stage reverse osmosis concentrate, particularly its scaling and corrosion tendencies. The temperature correction term incorporates the impact of water temperature changes on backwashing performance. Water temperature variations affect the physicochemical properties of water, as well as the solubility and reaction rate of impurities. Correction provides a more accurate reflection of water quality under actual backwashing conditions, avoiding deviations in backwashing performance due to temperature differences. The supersaturation correction term quantifies the potential for calcium scale formation in the water based on the difference between the calcium ion concentration and the calcium ion saturation concentration in the first-stage reverse osmosis concentrate. Higher supersaturation increases the risk of scaling. This correction allows for precise control of the supersaturation level of scaling substances in the water, providing a basis for preventing and treating scaling problems. The kinetic correction term considers the flow rate of the first-stage reverse osmosis concentrate and the roughness of the pipe wall in the delivery pipeline, taking into account the impact of kinetic processes such as impurity transport and sedimentation on backwashing performance. Flow velocity and pipe wall roughness affect the relative motion and friction between impurities and water flow, thus affecting the removal effect of impurities. After correction, the dynamic behavior of impurities during backwashing can be more accurately reflected.

[0014] 3. This invention selects filters of different precision according to different control levels to pre-treat the backwash water, which can effectively control the quality of the backwash water entering the ultrafiltration device. While ensuring the backwash effect, it avoids secondary pollution or damage to the ultrafiltration membrane due to poor backwash water quality, and further ensures the stable operation and long-term performance of the ultrafiltration membrane. Attached Figure Description

[0015] Figure 1 This is a diagram showing the module connections of the present invention.

[0016] Figure 2 This is a system connection diagram of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0019] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0021] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0022] Example 1: This embodiment provides a method for backwashing an ultrafiltration device using reverse osmosis concentrate, including the following steps: Water from the water purification station is obtained and then subjected to ultrafiltration and reverse osmosis treatments in sequence to obtain primary reverse osmosis concentrate. Obtain water quality data of the first-stage reverse osmosis concentrate; determine the Langrier correction term of the first-stage reverse osmosis concentrate; and obtain the Langrier index of the first-stage reverse osmosis concentrate based on the Langrier correction term and the water quality data. Control levels are determined based on the Langerile index; Depending on the control level, the ultrafiltration unit is backwashed using either primary reverse osmosis concentrate or permeate from the ultrafiltration unit.

[0023] Preferably, the Langerell correction term for the first-stage reverse osmosis concentrate includes: a temperature correction term, a supersaturation correction term, and a kinetic correction term, specifically: The Langerell correction term is obtained by summing the temperature correction term, the supersaturation correction term, and the kinetic correction term, and is expressed by the following formula: ; In the formula, Indicates the Langriel modification term. This indicates the temperature correction term. This indicates the oversaturation correction term. Indicates the dynamic correction term; The temperature correction term is expressed by the formula: ; In the formula, Indicates temperature-sensitive factor, This indicates the preset temperature difference, which is set based on the temperature difference between the inlet water temperature and the outlet water temperature of the ultrafiltration backwash water tank. The supersaturation correction term is expressed by the formula: ; In the formula, Represents the natural constant. Indicates the slope factor. Indicates the oversaturation threshold. The calcium ion concentration in the first-stage reverse osmosis concentrate is expressed as... Calculated, mg / L Indicates the saturation concentration of calcium ions, in Calculated, mg / L; The dynamic correction term is expressed by the formula: ; In the formula, , Represents the weight parameters. This indicates the flow rate of the first-stage reverse osmosis concentrate. This indicates the wall roughness of the pipeline that transports the first-stage reverse osmosis concentrate.

[0024] Preferably, the Langerell index includes the pH value of the first-stage reverse osmosis concentrate, the pH value of the first-stage reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate, and a Langerell correction term, specifically: The difference between the pH value of the first-stage reverse osmosis concentrate and the pH value of the first-stage reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate, plus a Langerier correction term, yields the Langerier index, expressed by the formula: ; In the formula, The Langerile index represents the concentrate from the first stage of reverse osmosis. This indicates the pH value of the first-stage reverse osmosis concentrate. This indicates the pH value of the first-stage reverse osmosis concentrate when it is saturated with calcium carbonate at the operating temperature.

[0025] Preferably, the pH value of the first-stage reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate is obtained based on the water quality data of the first-stage reverse osmosis concentrate, and is expressed by the formula: ; In the formula, Indicates total dissolved solids. Represents the logarithmic function with base 10. This indicates the temperature of the first-stage reverse osmosis concentrate. The alkalinity of the first-stage reverse osmosis concentrate is expressed in terms of... Calculated in mg / L.

[0026] Preferably, the steps for determining the control level based on the Langerhans index are as follows: Obtain the ion product of calcium sulfate, magnesium carbonate, and barium sulfate in the first-stage reverse osmosis concentrate; If the Langerel index and , , If so, then the control level is set to low; If the Langerel index and , , If so, then set the control level to medium; Otherwise, set the control level to high; In the formula, This represents the ion product of calcium sulfate. This represents the solubility product of calcium sulfate. This represents the ion product of magnesium carbonate. This represents the solubility product of magnesium carbonate. This represents the ion product of barium sulfate. This represents the solubility product of barium sulfate. The ion product of the calcium sulfate is expressed by the formula: ; In the formula, This indicates the calcium ion concentration in the first-stage reverse osmosis concentrate. This indicates the sulfate ion concentration in the first-stage reverse osmosis concentrate. The ion product of the magnesium carbonate is expressed by the formula: ; In the formula, This indicates the magnesium ion concentration in the first-stage reverse osmosis concentrate. This indicates the carbonate ion concentration in the first-stage reverse osmosis concentrate. The ion product of the barium sulfate is expressed by the formula: ; In the formula, This indicates the barium ion concentration in the first-stage reverse osmosis concentrate. This indicates the sulfate ion concentration in the first-stage reverse osmosis concentrate.

[0027] Preferably, if the control level is low, an ultrafiltration backwash security filter with a precision of 100 microns is used to filter the first-stage reverse osmosis concentrate, and the ultrafiltration unit is backwashed. If the control level is medium, use an ultrafiltration backwash security filter with an accuracy of 50 / 20 microns to filter the first-stage reverse osmosis concentrate and backwash the ultrafiltration unit. If the control level is high, an ultrafiltration backwash security filter with a precision of 100 microns is used to filter the water produced by the ultrafiltration unit, and the ultrafiltration unit is backwashed.

[0028] Implementation scenario: In a membrane-based boiler feedwater treatment system at a power plant, the backwash water for the ultrafiltration unit uses concentrated water from the first-stage reverse osmosis unit. The first-stage reverse osmosis unit has a net output of 100 t / h, a desalination rate of 97%, and a recovery rate of 75%. The water quality report for the water treatment plant states: =14.33mg / L =3.50mg / L =0.008mg / L =0、 =6.20mg / L, =190.00mg / L, alkalinity The concentration was 44.75 mg / L.

[0029] In the aforementioned power plant, the pH value of the primary reverse osmosis concentrate collected at a certain moment, measured under operating conditions, is obtained from the system proposed in this invention. =7.06, the inlet water temperature of the ultrafiltration backwash water tank t1=24.8℃, and the outlet water temperature of the ultrafiltration backwash water tank t2=24.3℃. =57.02mg / L, with The concentration is 142.55 mg / L. =13.79mg / L, = 0.03 mg / L, =0 mg / L =23.58mg / L, The alkalinity is 760.00 mg / L. The concentration was 175.26 mg / L. The concentration is 438.15 mg / L.

[0030] Based on the above data, we can conclude that: (1) pH value of the first-stage reverse osmosis concentrate: =7.06 (2) pH value of primary reverse osmosis concentrate at the operating temperature when calcium carbonate is saturated:

[0031] (Note: First-stage reverse osmosis concentrate temperature) =(t1+t2) / 2+273.15=297.7) (3) Langerlie correction : ① Temperature correction item =0.02×(24.8-24.3)=0.01; ② Supersaturation correction term ; Among them, calcium ion concentration =142.55mg / L=1.4255mmol / L, and because =0, =9.1×10 -6 Therefore, the saturation concentration of calcium ions =3.0166 mmol / L, therefore: ; ③ Dynamic correction term

[0032] in, =1.5m / s, stainless steel pipe wall roughness Ra=0.5 micrometers, therefore: ; therefore, = + + =0.01-0.2026-0.0305=-0.1331; (4) Langer's Index (LSI): =7.06-7.0808-0.1331=-0.1539<0; That is, to determine if the concentrated water is free of concentrators. Tendency to scale.

[0033] (5) Calculate the ion product, the ion product of magnesium carbonate, and the ion product of barium sulfate: = (57.02 / 40) × 10 -3 × (23.58 / 96) × 10 -3 =3.5014×10 -7 ; = (13.97 / 24) × 10 -3 × (0 / 60) × 10 -3 =0; = (0.03 / 137) × 10 -3 × (23.58 / 96) × 10 -3 =5.3786×10 -11 ; Upon investigation, the solubility products of calcium sulfate, magnesium carbonate, and barium sulfate were found to be: =9.1×10 -6 > ; =6.82×10 -6 > ; =1.1×10 -10 > ; The comparison showed that the ion product was less than the solubility product, indicating that the concentrated water did not have a tendency to precipitate calcium sulfate, magnesium carbonate, or barium sulfate. Therefore, the control level was low.

[0034] The backwash execution module controls the opening of the first and second control valves, and the closing of the third, fourth and fifth control valves. It also starts the backwash water pump, which delivers the primary reverse osmosis concentrate in the backwash water tank through the first security filter with a filtration accuracy of 100 microns to the ultrafiltration unit for backwashing.

[0035] Example 2: See Figure 1-2 This embodiment also provides a system for backwashing an ultrafiltration device using reverse osmosis concentrate, including an ultrafiltration module, a reverse osmosis module, a water quality detection module, a control module, and a backwashing module; The ultrafiltration module is used to process the water coming from the water purification station; The reverse osmosis module is used to process the water produced by the ultrafiltration unit and to produce primary reverse osmosis permeate and primary reverse osmosis concentrate, wherein the primary reverse osmosis permeate enters the subsequent desalination system. The water quality detection module is used to obtain water quality data of the first-stage reverse osmosis concentrate. The control module is used to set the control level and, based on the control level, control the backwash module to backwash the ultrafiltration unit using primary reverse osmosis concentrate or ultrafiltration unit permeate.

[0036] Preferably, the output end of the ultrafiltration module is connected to the input end of the reverse osmosis module, and the output ends of the ultrafiltration module and the reverse osmosis module are respectively connected to the input end of the backwashing module; The input terminal of the control module is communicatively connected to the output terminal of the water quality detection module, and the input terminal of the backwash module is communicatively connected to the output terminal of the control module. The water quality monitoring module includes multiple online water quality sensors for real-time monitoring of the pH value of the primary reverse osmosis concentrate under operating conditions. alkalinity calcium ion concentration magnesium ion concentration Barium ion concentration carbonate ion concentration Sulfate ion concentration and total dissolved solids (Parameters, etc.) and transmit them to the control module; The control module is used to determine the Langerelle correction term for the primary reverse osmosis concentrate (the portion of water that does not pass through the reverse osmosis membrane after the ultrafiltration unit's permeate has been treated by the primary reverse osmosis unit), and to obtain the Langerelle index of the primary reverse osmosis concentrate based on the Langerelle correction term and water quality data. The control level is obtained through the Langerelle index, and the backwash module is controlled to backwash the ultrafiltration module according to the control level.

[0037] Preferably, the ultrafiltration module includes a disc filter, an ultrafiltration device, and an ultrafiltration water tank; The output end of the disc filter is connected to the input end of the ultrafiltration device, and the output end of the ultrafiltration device is connected to the input end of the ultrafiltration water tank.

[0038] Preferably, the reverse osmosis module includes a first-stage reverse osmosis device; The input end of the first-stage reverse osmosis device is connected to the output end of the ultrafiltration water tank; The output of the first-stage reverse osmosis unit outputs first-stage reverse osmosis concentrate and reverse osmosis permeate, respectively.

[0039] Preferably, the backwash module includes an ultrafiltration backwash water tank, a reclaimed water tank, and a backwash water pump; The input end of the ultrafiltration backwash water tank is connected to the output end of the first-stage reverse osmosis unit and is used to store the first-stage reverse osmosis concentrate. The water quality detection module is located inside the ultrafiltration backwash water tank; The numerical detection module also includes a data preprocessing module, which processes the collected data into the required water quality data. The processing methods include noise reduction, signal amplification, and correction. The output end of the ultrafiltration backwash water tank is connected to the input end of the backwash water pump through the first control valve; The output end of the ultrafiltration backwash water tank is connected to the input end of the recycled water tank through the fifth control valve; the output end of the ultrafiltration water tank is connected to the input end of the backwash water pump through the fourth control valve. The output of the backwash pump backwashes the output of the ultrafiltration device through a second control valve or a third control valve.

[0040] Preferably, the backwashing module is controlled to backwash the output of the ultrafiltration module according to the control level. The specific steps are as follows: If the control level is low, the first and second control valves are opened, and the third, fourth, and fifth control valves are closed for backwashing. If the control level is medium, the first and third control valves are opened, and the second, fourth, and fifth control valves are closed for backwashing. If the control level is high, the second, fourth, and fifth control valves will be opened, while the first and third control valves will be closed for backwashing. The fifth control valve will be opened to discharge the first-stage reverse osmosis concentrate to the reclaimed water tank for recycling and storage.

[0041] Preferably, a first ultrafiltration backwashing security filter is provided between the second control valve and the ultrafiltration device; A second ultrafiltration backwashing security filter is installed between the third control valve and the ultrafiltration device; The first ultrafiltration backwash security filter has a precision of 100 micrometers, and the second ultrafiltration backwash security filter has a precision of 20 / 50 micrometers.

[0042] Preferably, the system further includes a storage and recording module for storing historical water quality data and recording historical backwashing records.

[0043] The system in this embodiment is used to implement the method described in Embodiment 1, and will not be repeated here.

[0044] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0045] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0046] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0047] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0048] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for backwashing an ultrafiltration device using reverse osmosis concentrate, characterized in that, Includes the following steps: Water from the water purification station is obtained and then subjected to ultrafiltration and reverse osmosis treatments in sequence to obtain primary reverse osmosis concentrate. Obtain water quality data for the first-stage reverse osmosis concentrate; The Langrehr correction terms for the first-stage reverse osmosis concentrate are determined, including temperature correction, supersaturation correction, and kinetic correction terms. Specifically: The Langerier correction term is obtained by summing the temperature correction term, the supersaturation correction term, and the kinetic correction term. The Langrier index of the primary reverse osmosis concentrate is obtained based on the Langrier correction term and water quality data. The Langrier index is calculated based on the pH value of the primary reverse osmosis concentrate, the pH value of the primary reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate, and the Langrier correction term. Specifically: The difference between the pH value of the first-stage reverse osmosis concentrate and the pH value of the first-stage reverse osmosis concentrate when calcium carbonate is saturated at the operating temperature is added to the Langrier correction term to obtain the Langrier index. The specific steps for determining control levels based on the Langerhans index are as follows: Obtain the ion product of calcium sulfate, magnesium carbonate, and barium sulfate in the first-stage reverse osmosis concentrate; If the Langerel index and , , If so, then the control level is set to low; If the Langerel index and , , If so, then set the control level to medium; Otherwise, set the control level to high; In the formula, This represents the ion product of calcium sulfate. This represents the solubility product of calcium sulfate. This represents the ion product of magnesium carbonate. This represents the solubility product of magnesium carbonate. This represents the ion product of barium sulfate. This represents the solubility product of barium sulfate. Based on the control level, determine whether to use primary reverse osmosis concentrate or ultrafiltration permeate to backwash the ultrafiltration unit. Specifically: If the control level is low, use an ultrafiltration backwash security filter with a precision of 100 microns to filter the first-stage reverse osmosis concentrate and backwash the ultrafiltration unit. If the control level is medium, use an ultrafiltration backwash security filter with an accuracy of 50 or 20 microns to filter the first-stage reverse osmosis concentrate and backwash the ultrafiltration unit. If the control level is high, an ultrafiltration backwash security filter with a precision of 100 microns is used to filter the water produced by the ultrafiltration unit, and the ultrafiltration unit is backwashed.

2. The method for backwashing an ultrafiltration device using reverse osmosis concentrate according to claim 1, characterized in that, The pH value of the first-stage reverse osmosis concentrate at the operating temperature when saturated with calcium carbonate is obtained based on the water quality data of the first-stage reverse osmosis concentrate.

3. A system for backwashing an ultrafiltration device using reverse osmosis concentrate, characterized in that, The system is capable of implementing the method of backwashing an ultrafiltration device with reverse osmosis concentrate as described in any one of claims 1 to 2, including an ultrafiltration module, a reverse osmosis module, a water quality detection module, a control module, and a backwashing module; The ultrafiltration module is used to treat the incoming water from the water purification station; the ultrafiltration module includes a disc filter, an ultrafiltration device, and an ultrafiltration water tank. The reverse osmosis module is used to process the water produced by the ultrafiltration unit and produce first-stage reverse osmosis concentrate. The water quality detection module is used to obtain water quality data of the first-stage reverse osmosis concentrate. The control module is used to set the control level and, based on the control level, control the backwash module to backwash the ultrafiltration unit using primary reverse osmosis concentrate or ultrafiltration unit permeate.

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