Reverse osmosis membrane is a common and important component in water treatment equipment, which can effectively filter out pollutants in water and achieve the goal of purified water. Generally, the service life of reverse osmosis membrane components is 3-5 years. After this service life, the reverse osmosis membrane components should be replaced and treated. Of course, the service life of membrane components is not fixed. If certain protection methods and precautions are taken for membrane components, their service life can be extended. How to prevent damage to the performance of reverse osmosis membranes? New reverse osmosis membrane components are usually soaked in 1% NaHSO3 and 18% glycerol aqueous solution and stored in sealed plastic bags. Storing the plastic bag for about 1 year without breaking it will not affect its lifespan and performance. After the plastic bag is opened, it should be used as soon as possible to avoid adverse effects on the components caused by NaHSO3 oxidation in the air. After the reverse osmosis equipment is tested, the following two methods can be used to protect the membrane. The equipment can be maintained using a 2% formaldehyde solution after two days of trial operation (15-24h); After running for 2-6 hours, a 1% NaHSO3 aqueous solution can be used for maintenance (the air in the equipment pipeline should be drained to ensure that the equipment does not leak, and all inlet and outlet valves should be closed). Both methods can achieve satisfactory results. The first method is slightly more expensive and can be used when idle for a long time, while the second method can be used when idle for a short period of time.
How to extend the service life of reverse osmosis membranes? During operation, reverse osmosis equipment may suffer from membrane performance damage due to improper operation, untimely cleaning, or incorrect cleaning. The following will analyze the reasons and solutions for the above two situations, in order to extend the service life of reverse osmosis membranes.
1、 Improper operation can cause membrane performance damage. Residual gas running under high pressure can form a gas hammer in reverse osmosis equipment, which can damage the membrane. There are often two situations that occur:
A. After the equipment is emptied, when it is restarted, the gas is quickly pressurized before it is fully discharged. The remaining air should be exhausted under a pressure of 2-4 bar before gradually increasing the pressure for operation.
B. When the joint between the pre-treatment equipment and the high-pressure pump is poorly sealed or leaks water (especially when the microfilter and its subsequent pipeline leak), if the pre-treatment water supply is insufficient and the microfilter is blocked, some air will be sucked in due to vacuum in the poorly sealed area. The microfilter should be cleaned or replaced to ensure that the pipeline does not leak. In short, the flow meter should be gradually pressurized and operated without any bubbles. If bubbles are found during operation, the pressure should be gradually reduced to investigate the cause.
The method for shutting down 02 is incorrect
A. Rapid depressurization during shutdown without thorough flushing. Due to the higher concentration of inorganic salts on the concentrated water side of the membrane compared to the raw water, it is prone to scaling and fouling of the membrane.
B. Rinse with pre treated water containing added chemical reagents. Water containing chemical reagents may cause membrane fouling during equipment shutdown When preparing to shut down the reverse osmosis equipment, stop adding chemical reagents and gradually reduce the pressure to around 3 bar. Rinse with pre treated water for 10 minutes until the TDS of the concentrated water is very close to that of the raw water.
03 Poor disinfection and maintenance lead to microbial contamination. Poor disinfection and maintenance of reverse osmosis equipment result in microbial contamination. This is a common problem in the use of composite polyamide films, as polyamide films have poor resistance to residual chlorine, and disinfectants such as chlorine are not properly added during use. In addition, users do not pay enough attention to microbial prevention, which can easily lead to microbial contamination. At present, many manufacturers produce pure water with excessive microorganisms, which is caused by inadequate disinfection and maintenance.
The main manifestation is that the RO equipment was not maintained with disinfectant at the time of leaving the factory; The entire pipeline and pre-treatment equipment were not disinfected after installation of the equipment; Intermittent operation without taking disinfection and maintenance measures; Not regularly disinfecting pre-treatment equipment and reverse osmosis equipment; Maintenance fluid failure or insufficient concentration.
Poor monitoring of residual chlorine in reverse osmosis equipment, such as pump failure or medication failure when adding NaHSO3, or membrane damage due to residual chlorine when activated carbon is saturated. 2、 Membrane performance damage caused by improper cleaning
