Microbial pollution control system and method for reverse osmosis cartridge filter

Abstract

The invention specifically discloses a microbial pollution prevention and control system and method for a reverse osmosis cartridge filter, and relates to the technical field of water treatment equipment. The system provided by the invention comprises a sterilization module, a cleaning module, a monitoring module and a control unit. The sterilization module is arranged between the security filter shell and the filter element, and provides a bacteriostatic environment for the filter during operation; the cleaning module comprises spraying pipes and a cleaning liquid supply unit, and the multiple spraying pipes are distributed between the shell and the filter element, communicate with the cleaning liquid supply unit and are used for cleaning the filter element; the monitoring module is arranged at the sewage draining exit and is used for monitoring the ORP value of sewage discharged after cleaning; the control unit communicates with all the modules and controls starting, stopping and switching of the sterilization module and the cleaning module according to the fed-back ORP value and preset conditions. The system is high in automation degree, can effectively inhibit breeding of microorganisms in the security filter, and greatly reduces the maintenance intensity and cost of the system.

Description

Technical Field

[0001] This invention relates to the technical field of industrial water treatment, and in particular to a reverse osmosis security filter microbial contamination prevention system and method. Background Technology

[0002] In reverse osmosis water treatment processes, security filters are critical protective devices before high-pressure pumps and are widely used in water treatment-related fields such as power plants. Their filter elements often utilize porous media materials such as polypropylene melt-blown. However, the porous structure of the filter element and its ability to trap organic matter make it prone to microbial growth. Internal pressure dead-end filtration leads to contaminant accumulation and a lack of self-cleaning ability, affecting the filter's operational stability.

[0003] Currently, the mainstream maintenance method in the industry is to replace the entire filter element when the pressure difference between the inlet and outlet water of the security filter (hereinafter referred to as: inlet-outlet pressure difference) increases. Furthermore, most existing filter elements are disposable, and there is no effective solution for addressing microbial growth and online cleaning during operation. This replacement method is costly, requires disassembling the filter, which is not only cumbersome and labor-intensive but also increases safety risks. It cannot suppress the large-scale proliferation of microorganisms in the middle of the filter element's lifespan, resulting in short filter operating cycles, frequent replacements, and a rapid increase in dynamic pressure difference after replacement. Simultaneously, disposable filter elements generate a large amount of waste pollutants, which is detrimental to the construction of environmentally friendly power plants. Existing technology lacks an integrated, automated solution for active antibacterial action and online cleaning and sterilization within the filter body. Summary of the Invention

[0004] This invention addresses the problems of passive maintenance, susceptibility to microbial contamination, and high maintenance and replacement workload of security filters by providing a system and method for preventing microbial contamination in reverse osmosis security filters. The system provided by this invention integrates daily active physical sterilization and online chemical cleaning and sterilization functions, meeting the daily maintenance needs of security filters.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a microbial contamination prevention system for a reverse osmosis security filter, comprising: A sterilization module is disposed between the housing and the filter element of the security filter, and is used to provide an antibacterial environment for the security filter during operation. A cleaning module, comprising spray pipes and a cleaning fluid supply unit, wherein several spray pipes are arranged between the housing and the filter element of the security filter; all spray pipes are connected to the cleaning fluid supply unit; used to clean the filter element of the security filter. A monitoring module is installed outside the drain outlet of the security filter to monitor the ORP value of the wastewater discharged after the cleaning module cleans the filter element; The control unit is communicatively connected to the cleaning module, sterilization module, and monitoring module. The monitoring module feeds back the measured ORP value to the control unit, and the control unit controls the start-up, shutdown, and switching of the sterilization module and the cleaning module according to preset conditions.

[0006] The sterilization module includes an ultraviolet lamp array, which is coaxially sleeved on the outside of the filter element; the ultraviolet light from the ultraviolet lamp array directly irradiates the outer surface of the filter element and the annular water flow space between the filter element and the housing; the ultraviolet lamp array is communicatively connected to the control unit.

[0007] The spray pipe is an annular spray pipe, which is coaxially sleeved on the outside of the filter element, and several nozzles are arranged on the side of the spray pipe near the filter element.

[0008] The cleaning fluid supply unit includes a cleaning fluid storage tank, a metering pump, and a third valve; the cleaning fluid storage tank is connected to each spray pipe through a pipeline; a metering pump and a third valve are sequentially installed on the pipeline near the cleaning fluid storage tank, and the metering pump is communicatively connected to the control unit.

[0009] The monitoring module includes an ORP meter, which is installed outside the fourth valve of the sewage discharge pipe of the security filter and is communicatively connected to the control unit.

[0010] The cleaning module's execution procedure includes: a liquid injection and soaking stage, a circulating spraying stage, a settling stage, and a rinsing and discharge stage.

[0011] The present invention also discloses a method for preventing microbial contamination of a reverse osmosis security filter using the above system, comprising the following steps: During normal filtration by the security filter, the sterilization module provides an antibacterial environment for the security filter; When the control unit detects that the pressure difference between the inlet and outlet water of the security filter exceeds the preset value, the control unit activates the cleaning module and pauses the filtration program and sterilization module of the security filter. The cleaning module injects the cleaning solution from the cleaning solution storage tank into the security filter through the spray pipe, and completes the cleaning of the security filter by soaking, circulating spraying and settling in sequence. After cleaning, the cleaning waste liquid is first drained, and then rinsed until the ORP value of the rinsing waste liquid drops to the preset value; the control unit restores the security filter to normal filtration mode and starts the sterilization module.

[0012] The cleaning solution is a hydrogen peroxide or sodium hypochlorite solution with a concentration range of 0.1% to 0.5%.

[0013] When the pressure difference between the inlet and outlet water exceeds 0.1~0.2MPa, the control unit activates the cleaning module and pauses the filtration program of the security filter and the sterilization module.

[0014] During normal filtration by the security filter, the control unit controls the UV lamp array of the sterilization module to operate continuously at 50%~70% of its rated power.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The system provided by this invention incorporates a sterilization module between the housing and filter element of a security filter. This module operates continuously during normal operation of the security filter, creating a sterile environment inside the filter and inhibiting the growth of biological contaminants at the source. Simultaneously, a cleaning module is integrated between the housing and filter element. When the pressure difference between the inlet and outlet water of the security filter exceeds a threshold, the online cleaning program of the cleaning module is activated. During cleaning, the cleaning solution penetrates deep into the filter element, effectively killing and removing microorganisms deep within the pores, achieving deep chemical sterilization of the filter element. The system automatically controls the switching between filtration, sterilization, and cleaning modes through a control unit. After cleaning, the monitoring module detects the ORP value of the rinsing wastewater in real time. Once the value reaches the standard, the filtration mode and sterilization module are immediately restarted, forming a complete protective closed loop. All modules of this system are integrated into the security filter body, requiring no major modifications to existing water treatment systems, resulting in low modification difficulty and cost. It is also suitable for the production and promotion of new intelligent filter products.

[0016] Furthermore, the sterilization module uses ultraviolet lamps, which directly irradiate the outer surface of the filter element and the annular water flow space between the filter element and the shell, making it difficult for microorganisms to colonize the filter element and maintaining the biological inertness of the security filter.

[0017] This invention utilizes a physical antibacterial mode through continuous operation of the sterilization module to significantly reduce the probability of microbial adhesion at the source. Combined with a deep sterilization mode through online chemical cleaning by the cleaning module, the two modes work synergistically to inhibit microbial growth and eradicate deep-seated contamination of the filter element, ensuring long-term stable anti-fouling performance. After effectively inhibiting biological contamination, the main factor causing the increase in the inlet and outlet water pressure difference of the security filter is particulate matter retention. This extends the filter element replacement cycle to be limited only by the particulate matter capacity, reducing the frequency of filter element replacement and significantly saving consumable costs. Simultaneously, the entire process requires no manual intervention or equipment disassembly, reducing maintenance workload and skill requirements, further saving maintenance costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a schematic diagram of the reverse osmosis security filter microbial contamination prevention system of the present invention; Figure 2 This is a schematic diagram of the structure of the spray pipe obtained by the present invention; The components include: 1. First valve; 2. Inlet pressure gauge; 3. Security filter housing; 4. Filter element; 5. Spray pipe; 6. Ultraviolet lamp array; 7. Outlet pressure gauge; 8. Second valve; 9. Cleaning fluid storage tank; 10. Metering pump; 11. Third valve; 12. Fourth valve; 13. Drainage ORP meter; and 14. Control unit. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of this invention, it should be noted that the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the product is in use. These are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In this application, the area away from the security filter is considered the outer side.

[0024] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0026] In reverse osmosis (RO) water treatment, the security filter, as the final physical barrier, is crucial for retaining suspended particles, colloids, and microorganisms that were not removed by upstream processes. However, the filter cartridge, constantly exposed to a humid and nutrient-rich environment, is highly susceptible to the growth of bacteria, algae, and biofilms. This leads to accelerated surface fouling, a rapid increase in operating pressure differential, a significantly shortened filtration cycle, and the potential risk of biofouling in downstream RO membranes. Current technologies generally address microbial contamination through periodic filter cartridge replacement, offline soaking disinfection, or manual disassembly and cleaning. These methods are cumbersome, involve long downtime, incomplete disinfection, and high personnel exposure risks. Especially in production operations with extremely stringent microbial control requirements, traditional methods are insufficient to meet the dual demands of continuous and stable operation and aseptic assurance.

[0027] The existing security filter includes a housing 3 and a filter element 4 disposed inside the housing 3. The filter element 4 is a cylindrical filter element. The upper part of the housing 3 is provided with a water inlet, and the bottom is provided with a water outlet and a sewage outlet. The water inlet is connected to the water inlet pipe. The water inlet pressure gauge 2 and the first valve 1 are arranged in sequence from the water inlet to the outside of the water inlet. The water outlet is connected to the water outlet pipe. The water outlet pressure gauge 7 and the second valve 8 are arranged in sequence from the water outlet to the outside of the water outlet. The sewage outlet is connected to the sewage outlet pipe. The sewage outlet is provided with a fourth valve 12.

[0028] Based on this, such as Figure 1 As shown, the microbial contamination prevention system for the reverse osmosis security filter provided by the present invention includes: a sterilization module, which is disposed between the housing 3 and the filter element 4 of the security filter, and is used to provide an antibacterial environment for the security filter during operation; The cleaning module includes spray pipes 5 and a cleaning fluid supply unit. Several spray pipes 5 are arranged between the housing 3 and the filter element 4 of the security filter. All spray pipes 5 are connected to the cleaning fluid supply unit and are used to clean the filter element 4 of the security filter. The monitoring module is located outside the drain outlet of the security filter and is used to monitor the ORP value of the wastewater discharged after the cleaning module cleans the filter element 4. The control unit 14 is communicatively connected to the cleaning module, the sterilization module, and the monitoring module. The monitoring module feeds back the measured ORP value to the control unit 14, and the control unit 14 controls the start-up, shutdown, and switching of the sterilization module and the cleaning module according to preset conditions.

[0029] The system provided by this invention employs a dual-mode linkage of continuous sterilization and online cleaning to achieve long-term stable maintenance of the security filter. The sterilization module operates continuously to inhibit the growth of microbial contamination, effectively extending the filter element's lifespan and reducing the frequency of replacement. The cleaning module can initiate cleaning operations promptly based on the actual operating conditions of the security filter, ensuring the equipment always maintains high-efficiency filtration performance. Furthermore, the entire protection system operates fully automatically without manual intervention, significantly reducing maintenance workload and overall costs.

[0030] In some specific embodiments, the sterilization module includes an ultraviolet lamp array 6, which is coaxially sleeved on the outside of the filter element 4; its ultraviolet light directly irradiates the outer surface of the filter element and the annular water flow space between the filter element and the housing; the ultraviolet lamp array 6 is communicatively connected to the control unit 14. In some embodiments, the ultraviolet lamp array 6 is a spiral ultraviolet lamp strip. When the security filter is operating normally, the interior of the filter is the primary site for microbial attachment and the initial formation of biofilm. An array of ultraviolet lamps is irradiating this annular region, allowing UVC photons to penetrate the water layer and directly act on the outer surface of the filter element and the microorganisms in the annular water, inhibiting their survival.

[0031] In some specific embodiments, the spray pipe 5 is an annular spray pipe, coaxially sleeved on the outside of the filter element 4, and several nozzles are arranged on the side of the spray pipe 5 near the filter element 4. The cleaning fluid supply unit includes a cleaning fluid storage tank 9, a metering pump 10, and a third valve 11; the cleaning fluid storage tank 9 is connected to each spray pipe 5 through pipelines; the metering pump 10 and the third valve 11 are sequentially arranged on the pipeline near the cleaning fluid storage tank 9, and the metering pump 10 is communicatively connected to the control unit 14.

[0032] When the pressure difference between the inlet and outlet water exceeds the threshold, the control unit receives the cleaning command and sequentially turns on the metering pump 10 and the third valve 11, closes the first valve 1 and the second valve 8, and injects a quantitative cleaning solution into the spray pipe 5 to clean the filter element.

[0033] In some specific implementations, the cleaning module's execution procedure includes: a liquid injection and soaking stage, a circulating spray stage, a settling stage, and a rinsing and discharge stage. Each stage is as follows: Liquid injection and soaking stage: Metering pump 10 and the third valve 11 are turned on, and metering pump 10 injects cleaning solution at a flow rate of 1L / min, raising the liquid level to completely cover the filter element and ensuring sufficient wetting of the filter element's outer wall; then soaking for 15-30 minutes, and opening the fourth valve 12 to discharge the cleaning waste liquid; Circulating spray stage: The fourth valve 12 is turned off and opened, and metering pump 10 and the third valve 11 are turned on, performing pulse spraying at a flow rate of 5L / min for 30 seconds on and 15 seconds off, continuing for 20 minutes to enhance the exchange of cleaning solution inside the filter element; Settling stage: The filter is kept in a sealed state and soaked for 15-30 minutes, and the fourth valve 12 is opened to discharge the waste liquid containing stripped contaminants; Rinsing and discharge stage: The first valve 1 is briefly opened, and the security filter is flushed and rinsed 2-3 times with the security filter's inlet water until the effluent ORP value drops below the preset value.

[0034] In some specific embodiments, the monitoring module includes an ORP (oxidation-reduction potential) meter 13, which is installed outside the fourth valve 12 of the sewage discharge pipe of the security filter. The ORP meter 13 is communicatively connected to the control unit 14. The ORP meter is used to monitor the oxidizing intensity of the waste liquid in real time and to determine whether to end the cleaning operation based on the real-time monitored ORP value.

[0035] In some embodiments, 3 to 5 spray pipes are coaxially arranged on the filter element 4; 16 fan-shaped nozzles are evenly distributed on the annular spray pipes, with a spray angle of 90°. The cleaning fluid storage tank is a 50L PE material cleaning fluid storage tank, and the first valve 1, the second valve 8, the third valve 11 and the fourth valve 12 are all solenoid valves.

[0036] The present invention also provides a method for preventing microbial contamination in a security filter using the above system, comprising the following steps: During normal filtration by the security filter, the sterilization module provides an antibacterial environment for the security filter; When the control unit 14 detects that the pressure difference between the inlet and outlet water of the security filter exceeds the preset value, the control unit 14 activates the cleaning module and pauses the filtration program and sterilization module of the security filter. The cleaning module injects the cleaning solution from the cleaning solution storage tank 9 into the security filter through the spray pipe 5, and completes the cleaning of the security filter by soaking, circulating spraying and settling in sequence. After cleaning, the cleaning waste liquid is first drained, and then rinsed until the ORP value of the rinsing waste liquid drops to the preset value; the control unit 14 restores the security filter to normal filtration mode and starts the sterilization module.

[0037] In some specific implementations, the cleaning solution in the cleaning fluid storage tank is either hydrogen peroxide or sodium hypochlorite solution, with a concentration ranging from 0.1% to 0.5%. Hydrogen peroxide has strong oxidizing properties and can efficiently decompose microorganisms. Its decomposition products are only water and oxygen, which are non-toxic, leave no residue, and are non-corrosive to commonly used filter cartridges. In practical applications, sodium hypochlorite solution can also be selected based on the water quality and microorganisms, as it is more cost-effective.

[0038] In some specific implementations, when the inlet and outlet water pressure difference exceeds a preset value, such as 0.1~0.2MPa, the control unit 14 activates the cleaning module and pauses the filtration and sterilization processes of the security filter. Simultaneously, it sets the conditions for cumulative operating time and timed cleaning to perform the cleaning operation. For example, the control unit can activate the cleaning module when the security filter has accumulated 200 hours of operation.

[0039] Example Mode 1: Normal filtration and continuous UV sterilization Raw water enters the housing 3 of the security filter through the first valve 1, passes through the filter element 4 from the outside in, and flows out from the second valve 8 at the bottom. Simultaneously, the control unit 14 controls the ultraviolet lamp array 6 to operate continuously at 50%~70% of its rated power. The ultraviolet light irradiates the outer wall of the filter element 4 and the entire annular cavity 360 degrees without blind spots, effectively inhibiting microbial activity.

[0040] Mode 2: Trigger the cleaning module When the system detects that the difference between the inlet pressure measured by inlet pressure gauge 2 and the outlet pressure measured by outlet pressure gauge 7 exceeds 0.1MPa~0.2MPa, the control unit 14 issues a command to pause the filtration program and sterilization module of the security filter; activate the cleaning module and switch to online cleaning mode; and automatically start the cleaning program. Switch mode: Close the first valve 1 and the second valve 8.

[0041] Immersion stage: Open the third valve 11, start the metering pump 10, and spray a certain concentration of cleaning solution evenly onto the outer wall of the filter element 4 through the spray pipe 5, filling the internal space of the security filter. After immersion for 15-30 minutes, discharge the waste liquid after cleaning.

[0042] Circulating spray stage: The metering pump 10 is briefly turned on to perform several short pulse sprays through the spray pipe 5 to enhance the exchange of cleaning fluid inside the filter element.

[0043] Settling stage: After settling for a period of time, open the fourth valve 12 at the bottom to discharge the waste liquid containing stripped contaminants.

[0044] Rinsing and Discharge Stage: Briefly open the first valve 1 and use the incoming water of the security filter to flush and drain the security filter 2-3 times until the ORP value of the effluent drops below 200mV.

[0045] Resumption of operation: Close the fourth valve 12, open the second valve 8, and then fully open the first valve 1 to restore normal filtration; the control unit 14 synchronously restarts the ultraviolet lamp array 6.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the claims of the present invention pending approval.

Claims

1. A microbial contamination prevention system for a reverse osmosis security filter, characterized in that, include: A sterilization module is disposed between the housing (3) and the filter element (4) of the security filter, and is used to provide an antibacterial environment for the security filter during operation; The cleaning module includes spray pipes (5) and a cleaning fluid supply unit. Several spray pipes (5) are arranged between the housing (3) and the filter element (4) of the security filter. All spray pipes (5) are connected to the cleaning fluid supply unit and are used to clean the filter element (4) of the security filter. The monitoring module is set outside the drain outlet of the security filter and is used to monitor the ORP value of the wastewater discharged after the cleaning module cleans the filter element (4). Control unit (14) is connected in communication with cleaning module, sterilization module and monitoring module; the monitoring module feeds back the measured ORP value to control unit (14), and control unit (14) controls the start-up, shutdown and switching of sterilization module and cleaning module according to preset conditions.

2. The microbial contamination prevention system for the reverse osmosis security filter according to claim 1, characterized in that, The sterilization module includes an ultraviolet lamp array (6), which is coaxially sleeved on the outside of the filter element (4); the ultraviolet light of the ultraviolet lamp array (6) directly irradiates the outer surface of the filter element (4) and the annular water flow space between the filter element (4) and the housing (3); the ultraviolet lamp array (6) is communicatively connected to the control unit (14).

3. The microbial contamination prevention system for the reverse osmosis security filter according to claim 1, characterized in that, The spray pipe (5) is an annular spray pipe, which is coaxially sleeved on the outside of the filter element (4). Several nozzles are arranged on the side of the spray pipe (5) close to the filter element (4).

4. The microbial contamination prevention system for the reverse osmosis security filter according to claim 1, characterized in that, The cleaning fluid supply unit includes a cleaning fluid storage tank (9), a metering pump (10), and a third valve (11); the cleaning fluid storage tank (9) is connected to each spray pipe (5) through a pipeline; the metering pump (10) and the third valve (11) are sequentially installed on the pipeline near the cleaning fluid storage tank (9), and the metering pump (10) is communicatively connected to the control unit (14).

5. The microbial contamination prevention system for the reverse osmosis security filter according to claim 1, characterized in that, The monitoring module includes an ORP meter (13), which is located outside the fourth valve (12) of the sewage pipe of the security filter. The ORP meter (13) is communicatively connected to the control unit (14).

6. The microbial contamination prevention system for the reverse osmosis security filter according to claim 1, characterized in that, The cleaning module's execution procedure includes: a liquid injection and soaking stage, a circulating spraying stage, a settling stage, and a rinsing and discharge stage.

7. A method for preventing microbial contamination of a reverse osmosis security filter using the system described in any one of claims 1-6, characterized in that, Includes the following steps: During normal filtration by the security filter, the sterilization module provides an antibacterial environment for the security filter; When the control unit (14) detects that the pressure difference between the inlet and outlet water of the security filter exceeds the preset value, the control unit (14) activates the cleaning module and pauses the filtration program and sterilization module of the security filter. The cleaning module injects the cleaning solution from the cleaning solution storage tank (9) into the security filter through the spray pipe (5), and completes the cleaning of the security filter by soaking, circulating spraying and settling in sequence. After cleaning, the cleaning waste liquid is drained first, and then rinsed until the ORP value of the rinsing waste liquid drops to the preset value; the control unit (14) restores the security filter to normal filtration mode and starts the sterilization module.

8. The method for preventing microbial contamination of a reverse osmosis security filter according to claim 7, characterized in that, The cleaning solution is a hydrogen peroxide or sodium hypochlorite solution with a concentration range of 0.1% to 0.5%.

9. The method for preventing microbial contamination of a reverse osmosis security filter according to claim 7, characterized in that, When the pressure difference between the inlet and outlet water exceeds 0.1~0.2MPa, the control unit (14) activates the cleaning module and pauses the filtration program and sterilization module of the security filter.

10. The method for preventing microbial contamination of a reverse osmosis security filter according to claim 7, characterized in that, During normal filtration of the security filter, the control unit (14) controls the UV lamp array (6) of the sterilization module to operate continuously at 50%~70% of its rated power.

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