1. How often should reverse osmosis systems be cleaned?
Generally, the RO system should be cleaned when the standardized flux decreases by 10 ~ 15%, or the system desalting rate decreases by 10 ~ 15%, or the operating pressure and interstage pressure difference increase by 10 ~ 15%. The frequency of cleaning is directly related to the degree of system pretreatment. When SDI15<3, the cleaning frequency may be 4 times per year. When SDI15 is around 5, the cleaning frequency may be doubled, but the cleaning frequency depends on the actual situation of each project site.
2. How many years can reverse osmosis membrane element be used generally?
The service life of the membrane depends on the chemical stability of the membrane, the physical stability of the components, the cleanability, the inlet water source, the pretreatment, the cleaning frequency, the operation management level and so on. Usually more than 5 years according to economic analysis.
3. How long is the maximum allowed shutdown without system flushing?
If the system uses the blocking agent, when the water temperature is between 20 and 38℃, about 4 hours. Below 20℃, about 8 hours. About 1 day if the system is not used with scale inhibitor.
4. Can reverse osmosis pure water system start and stop frequently?
Membrane system is based on continuous operation as the design benchmark, but in the actual operation, there will always be a certain frequency of start-up and shutdown. When the membrane system is shut down, it must be washed at low pressure with its produced water or water that has been pretreated and qualified, the concentrated water with high concentration and scale inhibitor must be replaced from the membrane elements. Measures should be taken to prevent leakage of water into the system and introduction of air, because if the components lose water and dry out, there may be an irreversible loss of water flux. If the shutdown is less than 24 hours, there is no need to take measures to prevent microbial growth. However, if the downtime exceeds the above provisions, protective solution shall be used as systematic storage or timed film flushing system.
5. How do you know which cleaning method to use for your membrane system?
In order to obtain the best cleaning effect, it is very important to choose the correct cleaning agent and cleaning procedure. The wrong cleaning will actually deteriorate the system performance. In general, acidic cleaning solution is recommended for inorganic scaling pollutants, and alkaline cleaning solution is recommended for microbial or organic pollutants.
