Maintenance of an RO Membrane

The RO membrane is the heart of any reverse osmosis system, and that’s why it is essential that a quality RO membrane is well maintained and kept in optimal working condition. The standard reverse osmosis process consists of three stages: pre-filtering, the reverse osmosis process, and post-filtering. Post-filter components are usually of carbon, which will remove any remaining taste and odor. Before changing these filters, make sure to shut off the water supply to your RO system. To successfully ensure efficiency out of your reverse osmosis system, certain routine maintenance steps must be performed. Frequency of maintenance depends on a number of factors, including water conditions and level of use. The filter needs to be replaced every 12-18 months, and the T.F.C membrane about every 24-60 months. Also, you must sanitize and recharge your system once a year.  The proper selection of chemicals and the order of cleaning steps are the keys to efficient membrane cleaning. Different membranes require different cleaning routines, so be sure to choose the correct one for your specific system.  Signs that you need to change your filter include water that has an offensive odor or taste. Cleaning is required when your reverse osmosis system shows signs of fouling. Membrane fouling is a perfect example of why your membrane should remain fresh. If not cleaned properly, it can increase the product water conductivity or salt passage, as well as decrease the normalized permeate flow’s output or flux. Fouling characteristics that signal you need to clean are a 10-15 % increase in normalized pressure drop as measured between the feed and concentrate headers. It is recommended that you sanitize your reverse osmosis system before the RO membrane is replaced. This is recommended every 2-3 years. Preconditioning, temperature transitions, and chemical addition sequences are all effective ways of cleaning a quality reverse osmosis membrane.