Water treatment control method of water treatment system for delaying aluminum pollution of nanofiltration membrane

Abstract

Provided in the present disclosure is a water treatment control method of a water treatment system for delaying the aluminum pollution of a nanofiltration membrane. The water treatment system comprises an ultrafiltration treatment system and a nanofiltration treatment system. The ultrafiltration treatment system comprises an ultrafiltration water supply system, an ultrafiltration membrane set and an ultrafiltration water production system which are successively connected by means of pipelines, a first addition pipeline being provided between the ultrafiltration water supply system and the ultrafiltration membrane set, and a first addition opening used for adding a scale inhibitor being provided in the first addition pipeline. The nanofiltration treatment system comprises a nanofiltration water supply system, a nanofiltration membrane set and a nanofiltration water production system which are successively connected by means of pipelines, the nanofiltration water supply system being communicated with the ultrafiltration water production system, a second addition pipeline being provided between the nanofiltration water supply system and the nanofiltration membrane set, and a third addition opening used for adding a scale inhibitor being provided in the second addition pipeline. The water treatment system for delaying the aluminum pollution provided in the embodiments of the present disclosure can delay the aluminum pollution of the nanofiltration membrane set, reduce the frequency of shutdown maintenance, and improve water treatment efficiency, thereby reducing the water production cost of the water treatment system.

Description

Water treatment control method for water treatment system to delay aluminum contamination of nanofiltration membrane

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application with application number 202310898091.4 filed with the Patent Office of China on July 21, 2023, entitled "Water Treatment Control Method for a Water Treatment System to Delay Aluminum Contamination of Nanofiltration Membranes," the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of water treatment, and in particular to a water treatment control method for a water treatment system for delaying aluminum contamination. Background Art

[0004] When it comes to water treatment, especially when it comes to deep water treatment, ultrafiltration and nanofiltration are common membrane separation treatment system combinations. Ultrafiltration serves as a pretreatment for nanofiltration, providing high-quality influent for nanofiltration. Typically, nanofiltration is performed using a roll-type nanofiltration system, and the membrane system's influent comes from the effluent of the water plant's existing conventional coagulation and sedimentation treatment system combined with sand filtration. Roll-type nanofiltration, however, requires strict pretreatment, requiring the influent SDI to be less than 5, the influent turbidity to be less than 0.5 NTU, and the influent aluminum to be less than 0.05 to 0.10 ppm. In contrast, sand filtration effluent often has an SDI of no less than 3 and often exceeds 5, a turbidity of 0.10 to 1.00 NTU, and an aluminum ion content of 0.10 to 0.19 ppm. Although ultrafiltration as a nanofiltration pretreatment can stabilize the SDI of its effluent below 5 and the turbidity no more than 0.10NTU, it has almost no interception ability for aluminum. As a result, the aluminum ions in the nanofiltration inlet water exceed the acceptable value of the system, causing aluminum contamination of the nanofiltration membrane. At the same time, the aluminum ions react with the scale inhibitor added during the nanofiltration operation to form colloidal precipitates attached to the inlet side of the nanofiltration membrane, which accelerates the pollution of the nanofiltration membrane on the one hand. On the other hand, due to the reduction in the effective content of the scale inhibitor, the scaling tendency on the concentrated water side of the nanofiltration membrane increases, further aggravating the pollution of the nanofiltration membrane, which in turn leads to frequent shutdown and maintenance of the nanofiltration membrane group and high water production costs of the system.

[0005] Summary of the Invention

[0006] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a water treatment system and a water treatment control method thereof for delaying aluminum pollution.

[0007] The present disclosure provides a water treatment system for delaying aluminum pollution, comprising: an ultrafiltration treatment system, wherein the ultrafiltration treatment system includes an ultrafiltration water supply system, an ultrafiltration membrane group and an ultrafiltration water production system connected in sequence through pipelines, a first dosing pipeline is provided between the ultrafiltration water supply system and the ultrafiltration membrane group, and the first dosing pipeline is provided with a first dosing port for adding a scale inhibitor and a second dosing port for adding a flocculant; a nanofiltration treatment system, wherein the nanofiltration treatment system includes a nanofiltration water supply system, a nanofiltration membrane group and a nanofiltration water production system connected in sequence through pipelines, the nanofiltration water supply system is connected to the ultrafiltration water production system, a second dosing pipeline is provided between the nanofiltration water supply system and the nanofiltration membrane group, and the second dosing pipeline is provided with a third dosing port for adding a scale inhibitor and a fourth dosing port for adding a reducing agent.

[0008] Optionally, the first dosing port and the second dosing port are spaced apart from each other, and the first dosing port is located upstream of the second dosing port.

[0009] Optionally, the nanofiltration treatment system also includes a nanofiltration cleaning system, which includes a nanofiltration cleaning pipe and a nanofiltration wastewater system. The upstream side of the nanofiltration membrane group has a nanofiltration cleaning port, the nanofiltration cleaning pipe is connected to the nanofiltration cleaning port, and the nanofiltration wastewater system is connected to the nanofiltration membrane group.

[0010] Optionally, the nanofiltration cleaning pipeline is provided with an acid filling port for adding acid.

[0011] Optionally, the water treatment system also includes: a program control system, which is used to detect various parameters in the water treatment system and control the operation of the ultrafiltration treatment system and the nanofiltration treatment system, and the program control system is used to dynamically adjust the addition amount of scale inhibitors, flocculants and acid solution according to the various parameters in the water treatment system.

[0012] The present disclosure also provides a water treatment control method for a water treatment system that delays aluminum contamination. The water treatment system for delaying aluminum contamination includes an ultrafiltration treatment system, a nanofiltration treatment system, and a program control system. The ultrafiltration treatment system and the nanofiltration treatment system both have water filtration and self-cleaning functions. The program control system is used to collect various parameters in the water treatment system, and the program control system is used to control the operation of the ultrafiltration treatment system and the nanofiltration treatment system according to the collected data. The water treatment control method includes:

[0013] Real-time detection and recording of various parameters within the water treatment system;

[0014] Starting the water filtration function of the ultrafiltration treatment system;

[0015] Starting the water filtration function of the nanofiltration treatment system;

[0016] Confirming that aluminum contamination occurs in the nanofiltration membrane group of the nanofiltration treatment system;

[0017] Determining the amount of scale inhibitor required to be added to the ultrafiltration treatment system and the amount of scale inhibitor required to be added to the nanofiltration treatment system;

[0018] Adding antiscaling agent to the ultrafiltration treatment system and the nanofiltration treatment system;

[0019] After running a filtration cycle, the self-cleaning function of the ultrafiltration treatment system is started to backwash the ultrafiltration membrane group of the ultrafiltration treatment system; the self-cleaning function of the nanofiltration treatment system is started to flush the nanofiltration membrane group of the nanofiltration treatment system.

[0020] Optionally, before the end of a filtration cycle, the water treatment control method includes:

[0021] Collecting various parameters in the water treatment system within a first preset time before the end of a filtration cycle;

[0022] Confirm that the nanofiltration membrane group needs to be intensively flushed;

[0023] Confirm the amount of acid added during intensive flushing.

[0024] Optionally, the enhanced flushing includes: an acid flushing stage, when the nanofiltration cleaning system of the nanofiltration treatment system is started, an appropriate amount of acid is added from the acid filling port of the nanofiltration cleaning system; and a deacidification flushing stage, after the acid flushing stage is completed, the acid filling port is closed and only conventional cleaning is performed.

[0025] Optionally, in a next filtration cycle after the cleaning cycle of the nanofiltration treatment system, the water treatment control method includes:

[0026] collecting the initial water inlet pressure of the nanofiltration treatment system after the filtration cycle begins;

[0027] Confirming that the nanofiltration membrane group of the nanofiltration treatment system needs to be subjected to restorative chemical cleaning;

[0028] The nanofiltration treatment system is shut down, and the nanofiltration membrane group is subjected to restorative chemical cleaning.

[0029] Optionally, before starting the nanofiltration treatment system, the water treatment control method further includes:

[0030] Detecting the water level of the ultrafiltration water production system of the ultrafiltration treatment system;

[0031] Confirm that the water level of the ultrafiltration water production system has reached a preset height.

[0032] The technical solution provided by the embodiments of the present disclosure has the following advantages over the prior art:

[0033] The water treatment system for delaying aluminum pollution provided by the embodiment of the present disclosure provides a first dosing port for adding scale inhibitors on the pipeline on the upstream side of the ultrafiltration membrane group. The scale inhibitors can be added from the first dosing port, and the amount of scale inhibitors added from the third dosing port can be reduced, so that a portion of aluminum ions are precipitated in the ultrafiltration treatment system, effectively reducing the aluminum ion content in the nanofiltration treatment system, delaying aluminum pollution of the nanofiltration membrane group, extending the service life of the nanofiltration membrane group, extending the use cycle of the nanofiltration membrane group, reducing the frequency of shutdown maintenance of the nanofiltration treatment system, improving the water treatment efficiency of the water treatment system, and reducing the water production cost of the water treatment system.

[0034] The water treatment control method provided by the embodiment of the present disclosure collects various parameters in the water treatment system in real time, and confirms the amount of scale inhibitor added from the first dosing port and the third dosing port based on the collected various parameters in the water treatment system. The amount of scale inhibitor added can be dynamically adjusted to maintain the amount of scale inhibitor added at a low level and maintain a good aluminum removal effect, effectively reducing aluminum contamination of the nanofiltration membrane group, extending the service life of the nanofiltration membrane group, extending the use cycle of the nanofiltration membrane group, and improving the water treatment efficiency of the water treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0036] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] FIG1 is a schematic diagram of a water treatment system for delaying aluminum contamination according to an embodiment of the present disclosure;

[0038] FIG2 is a flow chart of a water treatment control method of an ultrafiltration treatment system according to an embodiment of the present disclosure;

[0039] FIG3 is a flow chart of a water treatment control method of a nanofiltration treatment system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0042] Referring to Figure 1, the present disclosure provides a water treatment system for delaying aluminum pollution, including: an ultrafiltration treatment system and a nanofiltration treatment system, the ultrafiltration treatment system includes an ultrafiltration water supply system, an ultrafiltration membrane group and an ultrafiltration water production system, the ultrafiltration water supply system, the ultrafiltration membrane group and the ultrafiltration water production system are connected in sequence through pipelines, a first dosing pipeline is provided between the ultrafiltration water supply system and the ultrafiltration membrane group, and a first dosing port and a second dosing port are provided on the first dosing pipeline, the first dosing port is used to add scale inhibitors, and the second dosing port is used to add flocculants.

[0043] The ultrafiltration water supply system provides the required water inlet pressure for the filtration operation of the ultrafiltration treatment system. Specifically, the ultrafiltration water supply system includes an ultrafiltration water supply pump, which is used to transport raw water to the ultrafiltration membrane group.

[0044] The ultrafiltration membrane module is the core of the ultrafiltration system, separating solids from liquids in raw water, intercepting pollutants, and reducing turbidity to produce clear water. The ultrafiltration water production system provides a storage pool or tank for the ultrafiltration system's produced water and a drainage destination, while also providing high-quality feed water for the nanofiltration treatment system.

[0045] It should be explained that the raw water here refers to water that meets the water quality requirements that the ultrafiltration membrane group can withstand, such as water after sand filtration treatment.

[0046] The nanofiltration treatment system includes a nanofiltration water supply system, a nanofiltration membrane group and a nanofiltration water production system. The nanofiltration water supply system, the nanofiltration membrane group and the nanofiltration water production system are connected in sequence through pipelines. The nanofiltration water supply system is connected to the ultrafiltration water production system. A second dosing pipeline is provided between the nanofiltration water supply system and the nanofiltration membrane group. A third dosing port and a fourth dosing port are provided on the second dosing pipeline. The third dosing port is used for adding scale inhibitors, and the fourth dosing port is used for adding reducing agents.

[0047] The nanofiltration water supply system provides the required water inlet flow for filtration operation and the starting pressure required for the booster system operation. Specifically, the nanofiltration water supply system includes a nanofiltration water supply pump, which is used to transport raw water to the nanofiltration membrane group.

[0048] The nanofiltration membrane module is the core of the nanofiltration system, separating solids from liquids in raw water, intercepting pollutants, reducing organic matter, and removing salt and hardness to produce clear water. The nanofiltration water production system provides a storage pool or tank for the water produced by the nanofiltration system and a drainage destination.

[0049] When the water treatment system filters the raw water, the turbidity of the ultrafiltration inlet water of the ultrafiltration treatment system can be detected first, and then the amount of flocculant added at the second dosing port can be determined according to the turbidity of the ultrafiltration inlet water in the ultrafiltration treatment system. Then, the ultrafiltration treatment system can be started and the calculated amount of flocculant can be added simultaneously.

[0050] Specifically, the turbidity of ultrafiltration water is set to T NU , PAC dosage is to meet C1,

[0051] When T NU When it is below 0.3NTU, C1=0.5-2T NU / 3, the corresponding dosage is 0.3~0.5ppm;

[0052] When T NU When the temperature is 0.3~0.5NTU, C1=0.45-0.5T NU , the corresponding dosage is 0.2~0.3ppm;

[0053] When T NU When the temperature is 0.5~1.0NTU, C1=0.1+0.4T NU , the corresponding dosage is 0.3~0.5ppm.

[0054] After the water level in the ultrafiltration water production system reaches the starting conditions of the nanofiltration treatment system, the nanofiltration inlet water quality and operating parameters in the nanofiltration treatment system can be detected first. The nanofiltration inlet water quality includes but is not limited to the nanofiltration inlet water temperature and the nanofiltration inlet water conductivity, and the nanofiltration operating parameters include but are not limited to the nanofiltration membrane flux and recovery rate; then, the amount of scale inhibitor added at the third dosing port is determined according to the nanofiltration inlet water quality and operating parameters in the nanofiltration treatment system; then, the nanofiltration treatment system is started, and the calculated amount of scale inhibitor and reducing agent are added simultaneously.

[0055] Specifically, the nanofiltration inlet water temperature is set to T, the conductivity is E, the membrane flux is J, and the recovery rate is Y. The nanofiltration inlet scale inhibitor dosage is C2. C2 is determined by the coefficients a1, a2, b1, b2, c1, c2, d1, and d2 related to the water temperature T, conductivity E, membrane flux J, and recovery rate Y: a1 = (35-T) / 23, b1 = E / 200-0.5, c1 = 0.5J-11, and d1 = 0.2Y-16. When the nanofiltration inlet water temperature is above 12°C, a2 is 1, otherwise it is 0; when the nanofiltration inlet water conductivity is less than 300μs / cm, b2 is 1, otherwise it is 0; when the nanofiltration membrane flux is 20-22lmh, c2 is 1, otherwise it is 0; when the nanofiltration recovery rate is 80-85%, d2 is 1, otherwise it is 0. The dosage of nanofiltration inlet water scale inhibitor C2 = 3.0 + 0.075 (a1a2 + b1b2 + c1c2 + d1d2) - 0.375 (a2 + b2 + c2 + d2), and the corresponding dosage is 1.5 ~ 3.0 ppm.

[0056] During the filtration process of the water treatment system, a portion of the scale inhibitor injected from the third dosing port can be separated and injected from the first dosing port, that is, the calculated amount of scale inhibitor is divided into two parts and injected through the first dosing port and the third dosing port respectively. In this way, the aluminum ions in the treated water can be treated with the scale inhibitor twice, which can effectively reduce the aluminum ion content in the treated water flowing to the nanofiltration membrane group, reduce the aluminum contamination degree of the nanofiltration membrane group, and extend the service life of the nanofiltration membrane group.

[0057] Moreover, a portion of the scale inhibitor is added through the first dosing port. After reacting with aluminum ions, the scale inhibitor added from the first dosing port can react with the flocculant to form a relatively loose colloidal precipitate. The colloidal precipitate can be intercepted on the upstream side of the ultrafiltration membrane group, so that the aluminum content of the treated water after treatment by the ultrafiltration membrane group is lower, and less precipitation is formed on the upstream side of the nanofiltration membrane group, thereby delaying the aluminum pollution and clogging of the nanofiltration membrane group and extending the service life of the nanofiltration membrane group.

[0058] At the same time, more precipitation is formed on the upstream side of the ultrafiltration membrane group. Since the ultrafiltration membrane group can be backwashed, it can be cleaned more easily during the backwashing of the ultrafiltration membrane group, so that the ultrafiltration membrane group can maintain a good filtration effect after self-cleaning; moreover, less precipitation is formed on the upstream side of the nanofiltration membrane group, which can improve the flushing effect of the nanofiltration membrane group, reduce the frequency of the nanofiltration membrane group being shut down for restorative cleaning, and improve the filtration efficiency of the water treatment system.

[0059] According to the water treatment system provided by the embodiment of the present disclosure, by setting a first dosing port for adding scale inhibitors on the pipeline on the upstream side of the ultrafiltration membrane group, the scale inhibitors can be added from the first dosing port, and the amount of scale inhibitors added from the third dosing port can be reduced, so that a portion of aluminum ions are precipitated in the ultrafiltration treatment system, effectively reducing the aluminum ion content in the nanofiltration treatment system, reducing or eliminating aluminum contamination of the nanofiltration membrane group, extending the service life of the nanofiltration membrane group, extending the use cycle of the nanofiltration membrane group, reducing the frequency of shutdown maintenance of the nanofiltration treatment system, improving the water treatment efficiency of the water treatment system, and reducing the water production cost of the water treatment system.

[0060] In some embodiments of the present disclosure, the first dosing port and the second dosing port are spaced apart, and the first dosing port is located upstream of the second dosing port. Specifically, the distance between the first dosing port and the second dosing port is no less than 5 meters. This can reduce the mutual influence between the scale inhibitor and the flocculant, effectively avoiding the problem of poor aluminum ion elimination and impurity precipitation caused by direct reaction between the scale inhibitor and the flocculant. The scale inhibitor can fully react with the aluminum ions in the ultrafiltration treatment system, allowing the flocculant to fully precipitate impurities in the ultrafiltration treatment system, thereby improving the aluminum ion elimination effect and the water treatment efficiency of the ultrafiltration treatment system.

[0061] Referring to Figure 1, in some optional embodiments of the present disclosure, the ultrafiltration treatment system also includes an ultrafiltration cleaning system, the ultrafiltration cleaning system includes an ultrafiltration cleaning pipe and an ultrafiltration wastewater system, the downstream side of the ultrafiltration membrane group is provided with an ultrafiltration cleaning port, the ultrafiltration cleaning pipe is connected to the ultrafiltration cleaning port, and the ultrafiltration wastewater system is connected to the ultrafiltration membrane group.

[0062] Specifically, the ultrafiltration cleaning system provides physical and chemical cleaning for the ultrafiltration membrane group, removing pollutants that are blocked and attached to the surface of the membrane elements or inside the membrane fibers of the ultrafiltration membrane group to restore its initial filtration performance; the ultrafiltration wastewater system treats the ultrafiltration cleaning wastewater, which is directly discharged or reduced and neutralized to neutral before being discharged in compliance with the standards.

[0063] For example, the ultrafiltration cleaning pipeline can be equipped with a first cleaning dosing port, a second cleaning dosing port, and a third cleaning dosing port. The first cleaning dosing port is used to add acid, the second cleaning dosing port is used to add alkali, and the third cleaning dosing port is used to add fungicides. During the ultrafiltration membrane group cleaning process, acid, alkali, or fungicides can be added to neutralize the pH value of the ultrafiltration wastewater and eliminate bacteria in the ultrafiltration wastewater to meet discharge standards, thereby improving the cleaning effect.

[0064] After the ultrafiltration membrane group has been running for a certain period of time, the ultrafiltration water supply system and the ultrafiltration water production system and the ultrafiltration membrane group's ultrafiltration connecting valve can be automatically closed, and then the ultrafiltration cleaning system and the ultrafiltration wastewater system and the ultrafiltration membrane group's ultrafiltration cleaning connecting valve can be opened to flush the precipitate on the ultrafiltration membrane group and remove the precipitate on the ultrafiltration membrane group. After that, the ultrafiltration cleaning connecting valve can be closed and the ultrafiltration connecting valve can be opened again for water treatment.

[0065] This can make the ultrafiltration treatment system have a certain self-cleaning function. When the ultrafiltration membrane group is slightly contaminated or slightly blocked, restorative chemical cleaning is not required, which effectively improves the cleaning efficiency, improves the water treatment efficiency of the ultrafiltration treatment system, and thus improves the water treatment efficiency of the water treatment system.

[0066] Referring to Figure 1, in some embodiments of the present disclosure, the nanofiltration treatment system also includes a nanofiltration cleaning system, the nanofiltration cleaning system includes a nanofiltration cleaning pipe and a nanofiltration wastewater system, the upstream side of the nanofiltration membrane group is provided with a nanofiltration cleaning port, the nanofiltration cleaning pipe is connected to the nanofiltration cleaning port, and the nanofiltration wastewater system is connected to the nanofiltration membrane group.

[0067] After the nanofiltration membrane group has been running for a certain period of time, the nanofiltration water supply system and the nanofiltration water production system and the nanofiltration membrane group can be automatically closed. Then, the nanofiltration cleaning connecting valve between the nanofiltration cleaning system and the nanofiltration wastewater system and the nanofiltration membrane group can be opened to flush the precipitate on the nanofiltration module and remove the precipitate on the nanofiltration membrane group. After that, the nanofiltration cleaning connecting valve is closed and the nanofiltration connecting valve is opened again for water treatment.

[0068] This can make the nanofiltration treatment system have a certain self-cleaning function. When the nanofiltration membrane group is slightly contaminated or slightly blocked, restorative chemical cleaning is not required, which effectively improves the cleaning efficiency and the water treatment efficiency of the nanofiltration treatment system, thereby improving the water treatment efficiency of the water treatment system.

[0069] In some specific embodiments of the present disclosure, the nanofiltration cleaning pipeline is provided with an acid filling port for adding acid. Specifically, the acid added from the acid filling port may be hydrochloric acid or citric acid. When acid is added from the acid filling port, the rinse water used to clean the nanofiltration membrane array has a certain acidity, thereby effectively removing precipitates attached to the membrane elements of the nanofiltration membrane array, effectively reducing the degree of aluminum ion contamination of the membrane elements of the nanofiltration membrane array, and improving the self-cleaning effect of the nanofiltration treatment system.

[0070] In some embodiments of the present disclosure, the water treatment system further includes a programmable control system configured to detect various parameters within the water treatment system, control the operation of the ultrafiltration system, control the operation of the nanofiltration system, and dynamically adjust the amount of scale inhibitor, flocculant, and acid added based on the various parameters within the water treatment system. This allows for automated control of the water treatment system, enhances the intelligence level of the water system, and improves the filtration efficiency of the water treatment system.

[0071] 1, 2 and 3, the present disclosure further provides a water treatment control method for a water treatment system for delaying aluminum contamination. The water treatment system includes an ultrafiltration treatment system, a nanofiltration treatment system and a program control system. Both the ultrafiltration treatment system and the nanofiltration treatment system have water filtration and self-cleaning functions. The program control system is used to collect various parameters in the water treatment system. The program control system is used to control the operation of the ultrafiltration treatment system and the nanofiltration treatment system according to the collected data. The water treatment control method includes:

[0072] Real-time detection and recording of various parameters within the water treatment system; for example, various parameters within the water treatment system include ultrafiltration inlet turbidity, nanofiltration inlet water quality and operating parameters. The nanofiltration inlet operating conditions include but are not limited to nanofiltration inlet pressure, pressure difference, desalination rate, nanofiltration membrane flux and recovery rate.

[0073] Start the water filtration function of the ultrafiltration treatment system;

[0074] Start the water filtration function of the nanofiltration treatment system;

[0075] Confirm that aluminum contamination occurred in the nanofiltration membrane group of the nanofiltration treatment system;

[0076] Confirm the amount of antiscalant required for the ultrafiltration treatment system and the amount of antiscalant required for the nanofiltration treatment system;

[0077] Adding scale inhibitors to ultrafiltration treatment systems and nanofiltration treatment systems;

[0078] After running a filtration cycle, the self-cleaning function of the ultrafiltration treatment system is started to backwash the ultrafiltration membrane group of the ultrafiltration treatment system; the self-cleaning function of the nanofiltration treatment system is started to flush the nanofiltration membrane group of the nanofiltration treatment system.

[0079] Before starting the water treatment system, the turbidity of the ultrafiltration inlet water of the ultrafiltration treatment system is tested to calculate the amount of flocculant required to be added to the second dosing port. The inlet water quality and operating parameters of the nanofiltration treatment system are tested to calculate the amount of scale inhibitor required to be added to the third dosing port.

[0080] When the water treatment system is started for the first time, the water filtration function of the ultrafiltration treatment system can be started first, and the calculated amount of flocculant can be added simultaneously; when the water level in the ultrafiltration water production system reaches the preset value for starting the nanofiltration treatment system, the water filtration function of the nanofiltration treatment system is started, and the calculated amount of scale inhibitor is added simultaneously, and the operating pressure, pressure difference and desalination rate changes of the nanofiltration treatment system are recorded at the same time; specifically, the operating pressure, pressure difference and desalination rate changes within the first 5 minutes after the water filtration function of the nanofiltration treatment system is started can be recorded, and the operating pressure, pressure difference and desalination rate within 3 minutes before the water filtration function of the nanofiltration treatment system is about to end can be recorded.

[0081] After the first filtration cycle of the water filtration function of the ultrafiltration treatment system is completed, the self-cleaning function of the ultrafiltration treatment system is started to backwash the ultrafiltration membrane group; the self-cleaning function of the nanofiltration treatment system is started to perform ordinary cleaning on the nanofiltration membrane group, that is, only use the clean water after nanofiltration treatment to flush.

[0082] Before starting the second filtration cycle of the nanofiltration treatment system, the inlet water quality and operating parameters of the nanofiltration treatment system can be detected, and the dosage C2 of the scale inhibitor required to be dosed at the third dosing port can be calculated; then the water filtration function of the nanofiltration treatment system is started, and the calculated amount C2 of scale inhibitor and reducing agent is simultaneously dosed, and the operating pressure, pressure difference and desalination rate changes of the nanofiltration treatment system are recorded; specifically, the operating pressure, pressure difference and desalination rate within the first 5 minutes after the water filtration function of the nanofiltration treatment system is started can be recorded. And compare the changes in the operating pressure, pressure difference and desalination rate during the same period of this filtration with those during the same period of the previous filtration to determine whether it is necessary to add scale inhibitor from the first dosing port. If it is determined that the scale inhibitor does not need to be added from the first dosing port, add the calculated amount C2 of scale inhibitor from the third dosing port; if it is determined that the scale inhibitor needs to be added from the first dosing port, calculate the amount C3 of scale inhibitor that needs to be added from the first dosing port, and then divert the calculated amount C3 of scale inhibitor added from the third dosing port and add it from the first dosing port.

[0083] Specifically, the method for determining whether it is necessary to add the antiscalant from the first dosing port and the method for calculating the amount of antiscalant that needs to be added from the first dosing port are as follows:

[0084] Set the pressure at a certain moment within the first 5 minutes of the filtration-flushing cycle of the nanofiltration treatment system to be P 1,1 , the pressure difference is P 2,1 , desalination rate η 1,1 , the pressure at a certain moment within 5 minutes after the start of the previous filtration-flushing cycle is P 1,0 , the pressure difference is P 2,0 , desalination rate η 1,0 ;

[0085] Pressure change range △P1=P 1,1 -P 1,0 , pressure change rate △1=△P1 / P 1,0 , the pressure difference variation range △P2=P 2,1 -P 2,0 , pressure difference change rate △2=△P2 / P 2,0 , the variation range of desalination rate △η1=η 1,1 -η 1,0 The dosage of scale inhibitor added from the first dosing port of the ultrafiltration treatment system is C3.

[0086] When △1>0, △2>0, △η1>0 all appear and continue for 1 minute, it is determined that the membrane elements of the nanofiltration membrane group are slightly contaminated with aluminum. The nanofiltration treatment system needs to add part of the scale inhibitor added from the third dosing port to the ultrafiltration inlet water. At this time, the scale inhibitor dosage added from the first dosing port of the ultrafiltration treatment system is C3=0.3+15△η1, and the system limits C3 to a maximum of no more than 0.5ppm, and the corresponding dosage is 0.3~0.5ppm; at the same time, the actual dosage of the scale inhibitor added from the third dosing port of the corresponding nanofiltration treatment system is C 实 = C2 - C3. Otherwise, it is determined that the membrane elements of the nanofiltration membrane group are not contaminated by aluminum, and the antiscalant is only added from the third dosing port, and the amount added is C2.

[0087] After the water filtration function of the nanofiltration treatment system is completed, the self-cleaning function of the nanofiltration treatment system is started.

[0088] Repeat the above steps in the subsequent filtration-cleaning cycle of the water treatment system.

[0089] The disclosed embodiments provide a water treatment control method for a water treatment system for delaying aluminum contamination. By collecting various parameters in the water treatment system in real time and confirming the amount of scale inhibitor added from the first dosing port and the third dosing port based on the collected various parameters in the water treatment system, the amount of scale inhibitor added can be dynamically adjusted so that the amount of scale inhibitor added is maintained at a low level and a good aluminum removal effect is maintained, thereby effectively reducing aluminum contamination of the nanofiltration membrane group, extending the service life of the nanofiltration membrane group, extending the use cycle of the nanofiltration membrane group, and improving the water treatment efficiency of the water treatment system.

[0090] 1 , 2 and 3 , in some embodiments of the present disclosure, before a filtration cycle ends, the water treatment control method includes:

[0091] Collect various parameters in the water treatment system within a first preset time before the end of the filtration cycle;

[0092] Confirm that the nanofiltration membrane group of the nanofiltration treatment system needs to be intensively flushed;

[0093] Confirm the amount of acid added during intensive flushing.

[0094] When the water treatment system is started for the first time, the water filtration function of the ultrafiltration treatment system can be started first, and the calculated amount of flocculant can be added simultaneously; when the water level in the ultrafiltration water production system reaches the preset value for starting the nanofiltration treatment system, the water filtration function of the nanofiltration treatment system is started, and the calculated amount of scale inhibitor and reducing agent can be added simultaneously, and the operating pressure, pressure difference and desalination rate changes of the nanofiltration treatment system within the first preset time can be recorded; specifically, the operating pressure, pressure difference and desalination rate of the nanofiltration treatment system within 3 minutes before the water filtration function is about to end can be recorded.

[0095] After the first filtration cycle of the water filtration function of the ultrafiltration treatment system is completed, the self-cleaning function of the ultrafiltration treatment system is started to backwash the ultrafiltration membrane group; the self-cleaning function of the nanofiltration treatment system is started to perform ordinary cleaning on the nanofiltration membrane group, that is, only use the clean water after nanofiltration treatment to flush.

[0096] Then, the water filtration system of the nanofiltration treatment system is started, the second filtration cycle of the nanofiltration treatment system is started, and the operating pressure, pressure difference and desalination rate changes of the nanofiltration treatment system within the first preset time are recorded.

[0097] At a certain time before the start of the second cleaning cycle of the nanofiltration treatment system, the operating pressure, pressure difference, and salt rejection rate during the same period of this filtration can be compared with the operating pressure, pressure difference, and salt rejection rate during the same period of the previous filtration to determine whether the nanofiltration membrane group needs to be intensively flushed. If intensive flushing is determined to be necessary, the amount of acid to be added from the nanofiltration cleaning system is calculated; otherwise, conventional cleaning is performed.

[0098] Specifically, the method for determining whether the nanofiltration membrane group needs to be subjected to enhanced flushing and the calculation method for the dosage of the nanofiltration membrane group when the enhanced flushing is performed are as follows:

[0099] Set the pressure of the nanofiltration treatment system at a certain moment within 3 minutes before the end of the filtration-flushing cycle to P 3,1 , the pressure difference is P 4,1 , desalination rate η 2,1 , the pressure at a certain moment within 3 minutes before the end of the previous filtration-flushing cycle is P 3,0 , the pressure difference is P 4,0 , desalination rate η 2,0 ;

[0100] Pressure change range △P3=P 3,1 -P 3,0 , pressure change rate △3=△P3 / P 3,0 , the pressure difference variation range △P4=P 4,1 -P 4,0, pressure difference change rate △4=△P4 / P 4,0 , the variation range of desalination rate △η2=η 2,1 -η 2,0 , the dosage of enhanced flushing acid solution is C4.

[0101] If Δ3 > 3%, Δ4 > 5%, and Δη2 > 2% all occur for 1 minute, indicating increased aluminum contamination of the nanofiltration membrane elements, an enhanced rinse is performed. When the nanofiltration system's self-cleaning function is activated, acid is added for cleaning. The acid dosage for the enhanced rinse, C4, is calculated as 200 + 200 × (Δη2 - 2%) / 3%. The system limits C4 to a maximum of 400 ppm, corresponding to an acid dosage of 200 to 400 ppm and a pH of 2.0 to 5.0. Otherwise, aluminum contamination of the nanofiltration membrane elements has not increased, and the rinse is considered a routine clean.

[0102] By confirming the flushing type of the nanofiltration membrane group based on the various parameters collected in the water treatment system, the appropriate flushing type can be selected intelligently and accurately, reducing the use of acid, extending the restorative chemical cleaning cycle of the nanofiltration membrane group, reducing the frequency of restorative chemical cleaning of the nanofiltration membrane group, improving the filtration efficiency of the water treatment system, and reducing the operating cost of the water treatment system.

[0103] Referring to Figures 1, 2, and 3, in some specific embodiments of the present disclosure, the enhanced flushing includes an acid flushing phase and an acid removal flushing phase. When the nanofiltration cleaning system of the nanofiltration treatment system is activated, an appropriate amount of acid is added from the acid filling port of the nanofiltration cleaning system. After the acid flushing phase, the acid filling port is closed, and only conventional cleaning is performed. Specifically, the acid flushing phase and the acid removal flushing phase each occupy half of the cleaning cycle of the nanofiltration treatment system.

[0104] Adding acid solution for flushing first can effectively clean the precipitation on the membrane elements of the nanofiltration membrane group, unclog the filter holes of the membrane elements of the nanofiltration membrane group, and enable the nanofiltration membrane group to restore a better filtration effect; after the acid flushing stage is completed, the acid removal flushing stage is carried out to effectively flush away the acid remaining on the membrane elements of the nanofiltration membrane group during the acid flushing stage, effectively reducing the influence of the residual acid on the filtration performance of the nanofiltration membrane group, so that after the enhanced flushing, the nanofiltration membrane group can maintain a better filtration performance.

[0105] 1 and 3 , in some optional embodiments of the present disclosure, in a next filtration cycle after a cleaning cycle of the nanofiltration treatment system, the water treatment control method includes:

[0106] Collect the initial water inlet pressure of the nanofiltration treatment system after the filtration cycle begins;

[0107] Confirm that the nanofiltration membrane group needs to be cleaned with restorative chemical cleaning;

[0108] Shut down the nanofiltration treatment system and perform restorative chemical cleaning on the nanofiltration membrane group.

[0109] When the filtration function of the nanofiltration treatment system is started for the second time and thereafter, at the beginning of the filtration cycle, the initial water inlet pressure of the nanofiltration treatment system is recorded and compared with the initial water inlet pressure when the filtration function of the nanofiltration treatment system is started for the first time to determine whether the nanofiltration membrane group needs to be restorative chemically cleaned; if the initial water inlet pressure during this filtration cycle is not greater than the initial water inlet pressure during the first filtration cycle, or the initial water inlet pressure during this filtration cycle is greater than the initial water inlet pressure during the first filtration cycle and the pressure change increase is not greater than 10%, it means that the flushing effect of the self-cleaning function of the nanofiltration treatment system is good, the nanofiltration membrane group has recovered to the preset filtration performance, and the filtration function can continue.

[0110] If the initial water inlet pressure during the current filtration cycle is greater than the initial water inlet pressure during the first filtration cycle, and the pressure change increase is greater than 10%, it means that the flushing effect of the self-cleaning function of the nanofiltration treatment system in the previous cycle is poor, and it is determined that the self-cleaning function of the nanofiltration treatment system cannot restore the nanofiltration membrane group to the preset filtration performance. It is determined that the nanofiltration membrane group needs to be restorative chemically cleaned, and then the nanofiltration treatment system is shut down and the nanofiltration membrane group is subjected to restorative chemical cleaning;

[0111] After the nanofiltration membrane group is subjected to restorative chemical cleaning, filtration is continued to reset the filtration-cleaning cycle of the nanofiltration treatment system, and the initial water inlet pressure at the beginning of the first filtration cycle after the nanofiltration membrane group is subjected to restorative chemical cleaning is recorded. The initial water inlet pressure at the beginning of this filtration cycle is recorded as the initial water inlet pressure during the first filtration cycle of the nanofiltration treatment system.

[0112] By comparing the initial water inlet pressure at each filtration cycle with the first, it is possible to more accurately determine whether the nanofiltration membrane group has recovered to the preset filtration performance. When the nanofiltration membrane group has not recovered to the preset filtration performance, the nanofiltration treatment system can be shut down in time and the nanofiltration membrane group can be subjected to restorative chemical cleaning. This can effectively ensure the filtration performance of the nanofiltration treatment system, ensure that the water treated by the nanofiltration treatment system meets the preset requirements, and ensure the reliability of the nanofiltration treatment system.

[0113] 1 and 2 , in some specific embodiments of the present disclosure, when the backwash times of the ultrafiltration membrane group reaches a preset value, the water treatment control method includes: performing maintenance chemical cleaning on the ultrafiltration membrane group, that is, when the ultrafiltration cleaning system is turned on, adding acid, alkali solution, and bactericide in a certain order to restore the filtration performance of the ultrafiltration membrane group, improve the reliability of the ultrafiltration membrane group, and extend the service life of the ultrafiltration membrane group.

[0114] 1 and 2 , in some specific embodiments of the present disclosure, in the next filtration cycle after the maintenance chemical cleaning of the ultrafiltration treatment system is completed, the water treatment control method includes:

[0115] Collect the initial water inlet pressure of the ultrafiltration treatment system after the filtration cycle begins;

[0116] Confirm that the ultrafiltration membrane group needs to be cleaned with restorative chemical cleaning;

[0117] Shut down the ultrafiltration treatment system and perform restorative chemical cleaning on the ultrafiltration membrane group.

[0118] After the maintenance chemical cleaning of the ultrafiltration treatment system is completed, the filtration function is turned on. At the beginning of the filtration cycle, the initial water inlet pressure of the ultrafiltration treatment system is recorded and compared with the initial water inlet pressure when the ultrafiltration treatment system first starts the filtration function to determine whether the ultrafiltration membrane group needs to be restorative chemically cleaned; if the initial water inlet pressure during this filtration cycle is not greater than the initial water inlet pressure during the first filtration cycle, or the initial water inlet pressure during this filtration cycle is greater than the initial water inlet pressure during the first filtration cycle and the pressure change increase is not greater than 50%, it means that the flushing effect of the self-cleaning function of the ultrafiltration treatment system is good, the ultrafiltration membrane group has recovered to the preset filtration performance, and the filtration function can continue.

[0119] If the initial water inlet pressure during the current filtration cycle is greater than the initial water inlet pressure during the first filtration cycle, and the pressure change increase is greater than 50%, it means that the flushing effect of the self-cleaning function of the ultrafiltration treatment system in the previous cycle is poor, and it is determined that the self-cleaning function of the ultrafiltration treatment system cannot restore the ultrafiltration membrane group to the preset filtration performance. It is determined that the ultrafiltration membrane group needs to be restorative chemically cleaned, and then the ultrafiltration treatment system is shut down and the ultrafiltration membrane group is subjected to restorative chemical cleaning;

[0120] After the ultrafiltration membrane group is subjected to restorative chemical cleaning, filtration is continued, the filtration-cleaning cycle of the ultrafiltration treatment system is reset, and the initial water inlet pressure at the beginning of the first filtration cycle after the ultrafiltration membrane group is subjected to restorative chemical cleaning is recorded, and the initial water inlet pressure at the beginning of this filtration cycle is recorded as the initial water inlet pressure during the first filtration cycle of the ultrafiltration treatment system.

[0121] By comparing the initial water inlet pressure at each filtration cycle with the first, it is possible to more accurately determine whether the ultrafiltration membrane group has recovered to the preset filtration performance. When the ultrafiltration membrane group has not recovered to the preset filtration performance, the ultrafiltration treatment system can be shut down in time and the ultrafiltration membrane group can be subjected to restorative chemical cleaning. This can effectively ensure the filtration performance of the ultrafiltration treatment system, ensure that the water treated by the ultrafiltration treatment system meets the preset requirements, and ensure the reliability of the ultrafiltration treatment system.

[0122] 1 and 3 , before starting the nanofiltration treatment system, the water treatment control method further includes:

[0123] Detect the water level of the ultrafiltration water production system of the ultrafiltration treatment system;

[0124] Confirm that the water level of the ultrafiltration water production system has reached the preset height.

[0125] When the ultrafiltration membrane group is backwashed, CEB (maintenance chemical cleaning) or CIP (restorative chemical cleaning), this can avoid the nanofiltration treatment system from running dry, which can effectively reduce the water production cost of the water treatment system and improve the overall performance of the water treatment system.

[0126] The present invention will be described below with reference to specific embodiments.

[0127] For example, at a certain project site, the water inlet of the water treatment system is the sand filter effluent from the surface water source water supply plant. The turbidity of the sand filter effluent is 0.35-0.45 NTU, the water temperature is 13-16°C, the conductivity is 330-425 μs / cm, the nanofiltration membrane flux is set to 24 lmh, and the recovery rate is 85%.

[0128] During the initial operation and filtration process of the water treatment system, according to the set conditions, the turbidity of the inlet water of the ultrafiltration treatment system is 0.35~0.45NTU, then the inlet PAC dosage of the ultrafiltration treatment system is 0.225~0.275ppm, the inlet water quality of the nanofiltration treatment system meets the set operating parameters of the nanofiltration inlet water temperature above 12℃ and the recovery rate is 80~85%, and the inlet scale inhibitor dosage of the nanofiltration treatment system is 2.39~2.40ppm.

[0129] At this time, the pressure in the first 5 minutes of the initial operation of the nanofiltration treatment system during the first filtration-flushing cycle was 0.410-0.412 MPa, the pressure difference was 0.361-0.365 bar, and the desalination rate was 84.9-85.2%. The pressure in the 3 minutes before flushing was 0.413-0.416 MPa, the pressure difference was 0.364-0.370 bar, and the desalination rate was 84.8-85.3%. During the first 5 minutes of the second filtration-flushing cycle, the pressure was 0.411-0.413 MPa, the differential pressure was 0.362-0.365 bar, and the rejection rate was 85.0-85.2%. Δ1 > 0, Δ2 > 0, and Δη1 > 0 all occurred but did not persist for 1 minute, indicating that the nanofiltration module's membrane elements were not at the level of minimal aluminum contamination. The scale inhibitor was continued to be added to the third dosing port of the nanofiltration system and was not diverted to the first dosing port of the ultrafiltration system, continuing operation. During the 3 minutes before the start of the second filtration-flushing cycle, the pressure was 0.414-0.417 MPa, the differential pressure was 0.364-0.369 bar, and the rejection rate was 85.0-85.4%. Δ3 > 3%, Δ4 > 5%, and Δη2 > 2% all did not occur, indicating that the nanofiltration module's membrane elements were not at the level of severe contamination. This flush was maintained as a regular flush, and no enhanced flush was performed. The system continued operation.

[0130] During the sixth filtration-flush cycle on the sixth day of nanofiltration operation, Δ1>0, Δ2>0, and Δη1>0 all appeared and remained constant for 1 minute, indicating minimal contamination of the nanofiltration membrane elements. Antiscalant was diverted to the first dosing port of the ultrafiltration system, where Δη1 was 0.24-0.36%. The dosage of antiscalant at the first dosing port of the ultrafiltration system was 0.336-0.354 ppm. During the seventh filtration-flush cycle on the seventh day of operation, Δ1>0, Δ2>0, and Δη1>0 all appeared but did not remain constant for 1 minute. No antiscalant was added to the first dosing port of the ultrafiltration system. The system continued operation.

[0131] On the 10th day of the nanofiltration system's operation, during the 10th filtration-rinse cycle, Δ3 > 3%, Δ4 > 5%, and Δη2 > 2% all showed signs of sustained activity for 1 minute, indicating increased aluminum contamination of the nanofiltration membrane. This rinse was an enhanced rinse, with a Δη2 range of 2.3-3.9% and an acid dosage of 220-260 ppm, with a maximum of 260 ppm, corresponding to a pH of 3.8. On the 11th day of the system's operation, during the 10th cycle of the enhanced rinse, Δ1 > 0, Δ2 > 0, and Δη1 > 0 all showed signs of sustained activity for 1 minute, but were not sustained for 1 minute. Δ3 > 3%, Δ4 > 5%, and Δη2 > 2% all did not show signs of sustained activity. The system then continued operation.

[0132] From Days 12 to 62, or the 12th to 62nd filtration-flushing cycle, antiscalant was added to the first dosing port of the ultrafiltration system for 20 cycles, and enhanced flushing was performed 13 times. During these periods, the initial operating pressure after flushing of the nanofiltration system increased by no more than 10% compared to the first filtration-flushing cycle. Furthermore, the increase in differential pressure after ultrafiltration CEB was less than 50%, demonstrating the effectiveness of both nanofiltration flushing and ultrafiltration CEB.

[0133] The nanofiltration treatment system was in operation for 63 days, and the initial operating pressure was 0.453~0.459Mpa. Compared with the first filtration-flushing cycle, the pressure change increased by more than 10%. At this time, the flushing effect was poor, and the nanofiltration treatment system was shut down for CIP operation. After CIP, the system pressure recovered to about 0.41Mpa. The CIP operation cycle of this nanofiltration treatment system was 63 days. During the same period, the conventionally operated nanofiltration treatment system (i.e., the nanofiltration treatment system that only added scale inhibitors at the third dosing port) underwent 2 CIPs, with intervals of 23 days and 25 days respectively. It can be seen that the use of the water treatment control method of the present invention can effectively delay and eliminate aluminum pollution, extend the CIP frequency of the nanofiltration membrane treatment system, and improve production efficiency.

[0134] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0135] The foregoing description is intended only to provide specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments described herein, but rather to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A water treatment control method for a water treatment system for delaying aluminum contamination of a nanofiltration membrane, characterized in that: The water treatment system comprises: An ultrafiltration treatment system, the ultrafiltration treatment system comprising an ultrafiltration water supply system, an ultrafiltration membrane group and an ultrafiltration water production system connected in sequence by pipelines, a first dosing pipeline is provided between the ultrafiltration water supply system and the ultrafiltration membrane group, and the first dosing pipeline is provided with a first dosing port for adding a scale inhibitor and a second dosing port for adding a flocculant; A nanofiltration treatment system, the nanofiltration treatment system comprising a nanofiltration water supply system, a nanofiltration membrane group and a nanofiltration water production system connected in sequence by pipelines, the nanofiltration water supply system is connected to the ultrafiltration water production system, a second dosing pipeline is provided between the nanofiltration water supply system and the nanofiltration membrane group, and the second dosing pipeline is provided with a third dosing port for adding a scale inhibitor and a fourth dosing port for adding a reducing agent; A program control system, wherein both the ultrafiltration treatment system and the nanofiltration treatment system have water filtering function and self-cleaning function, and the program control system is used to collect various parameters in the water treatment system, and the program control system is used to control the operation of the ultrafiltration treatment system and the nanofiltration treatment system according to the collected data; The water treatment control method of the water treatment system for delaying aluminum contamination of the nanofiltration membrane comprises: Real-time detection and recording of various parameters in the water treatment system, including: nanofiltration inlet water temperature T, nanofiltration inlet water conductivity E, nanofiltration membrane flux J, nanofiltration recovery rate Y; pressure P 1,1, pressure difference P 2,1, and desalination rate η1,1 at a certain time within 5 minutes before the start of the current filtration-flushing cycle of the nanofiltration treatment system, and pressure P 1,0, pressure difference P 2,0, and desalination rate η1,0 at a certain time within 5 minutes after the start of the previous filtration-flushing cycle; wherein, pressure change amplitude △P1=P 1,1-P 1,0, pressure change rate △1=△P1 / P 1,0, pressure difference change amplitude △P2=P 2,1-P 2,0, pressure difference change rate △2=△P2 / P 2,0, and desalination rate change amplitude △η1=η1,1-η1,0; According to the influent water quality and operating parameters of the nanofiltration treatment system, determine the amount of scale inhibitor C2 that the nanofiltration treatment system needs to add from the third dosing port, the nanofiltration influent water quality includes but is not limited to the nanofiltration influent water temperature and nanofiltration influent conductivity, and the nanofiltration operating parameters include but are not limited to the nanofiltration membrane flux and recovery rate; C 2=3.0+0.075(a1a2+b1b2+c1c2+d1d2)-0.375(a2+b2+c2+d2), the corresponding dosage C 2 is 1.5~3.0ppm; wherein, a1=(35-T) / 23, b1=E / 200-0.5, c1=0.5J-11, d1=0.2Y-16, when the nanofiltration inlet water temperature is above 12℃, a2 is 1, otherwise it is 0; when the nanofiltration inlet water conductivity is lower than 300μs / cm, b2 is 1, otherwise it is 0; when the nanofiltration membrane flux is 20~22lmh, c2 is 1, otherwise it is 0; when the nanofiltration recovery rate is 80~85%, d2 is 1, otherwise it is 0; Starting the water filtration function of the ultrafiltration treatment system; Starting the water filtration function of the nanofiltration treatment system; When △1>0, △2>0, and △η1>0 all appear and continue for 1 minute, it is confirmed that the nanofiltration membrane group of the nanofiltration treatment system is contaminated with aluminum; A portion of the scale inhibitor that needs to be added from the third dosing port of the nanofiltration treatment system is separated and added from the first dosing port to the ultrafiltration treatment system, and the amount of scale inhibitor C3 that needs to be added from the first dosing port of the ultrafiltration treatment system and the amount of scale inhibitor Cact that needs to be added from the third dosing port of the nanofiltration treatment system are confirmed; wherein, the amount of scale inhibitor added from the first dosing port C3=0.3+15△η1, and the system limits C3 to a maximum of no more than 0.5ppm, and the corresponding dosage is 0.3-0.5ppm; the amount of scale inhibitor added from the third dosing port Cact=C2-C3; Adding antiscaling agent to the ultrafiltration treatment system and the nanofiltration treatment system; After running a filtration cycle, the self-cleaning function of the ultrafiltration treatment system is started to backwash the ultrafiltration membrane group of the ultrafiltration treatment system; the self-cleaning function of the nanofiltration treatment system is started to flush the nanofiltration membrane group of the nanofiltration treatment system; The scale inhibitor introduced from the first dosing port reacts with aluminum ions and then with flocculants to form relatively loose colloidal precipitation, and the colloidal precipitation is intercepted on the upstream side of the ultrafiltration membrane group.

2. The water treatment control method according to claim 1, characterized in that: The first dosing port and the second dosing port are spaced apart from each other, and the first dosing port is disposed on the upstream side of the second dosing port.

3. The water treatment control method according to claim 1, characterized in that: The nanofiltration treatment system also includes a nanofiltration cleaning system, which includes a nanofiltration cleaning pipeline and a nanofiltration wastewater system. The upstream side of the nanofiltration membrane group has a nanofiltration cleaning port, the nanofiltration cleaning pipeline is connected to the nanofiltration cleaning port, and the nanofiltration wastewater system is connected to the nanofiltration membrane group.

4. The water treatment control method according to claim 3, characterized in that: The nanofiltration cleaning pipeline is provided with an acid filling port for adding acid.

5. The water treatment control method according to claim 1, characterized in that: Before the end of a filtration cycle, the water treatment control method includes: Collect various parameters in the water treatment system within a first preset time before the end of the filtration cycle; Confirm that the nanofiltration membrane group needs to be intensively flushed; Confirm the amount of acid to be added during intensive flushing.

6. The water treatment control method according to claim 5, characterized in that: The enhanced flushing includes: In the acid flushing stage, when the nanofiltration cleaning system of the nanofiltration treatment system is started, an appropriate amount of acid is added from the acid filling port of the nanofiltration cleaning system; In the acid removal and rinsing stage, after the acid addition and rinsing stage is completed, the acid filling port is closed and only conventional cleaning is performed.

7. The water treatment control method according to claim 1, characterized in that: In the next filtration cycle after the cleaning cycle of the nanofiltration treatment system ends, the water treatment control method includes: Collecting the initial water inlet pressure of the nanofiltration treatment system after the filtration cycle begins; Confirming that the nanofiltration membrane group of the nanofiltration treatment system needs to be subjected to restorative chemical cleaning; The nanofiltration treatment system is shut down, and the nanofiltration membrane group is subjected to restorative chemical cleaning.

8. The water treatment control method according to claim 1, characterized in that: Before starting the nanofiltration treatment system, the water treatment control method further includes: Detecting the water level of the ultrafiltration water production system of the ultrafiltration treatment system; Confirm that the water level of the ultrafiltration water production system has reached a preset height.

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