As the "heart" of reverse osmosis equipment, the RO membrane is also one of the most valuable consumable parts. Its normal service life is 2–3 years. However, improper maintenance may lead to replacement within only half a year, greatly increasing operational costs. Below is a golden daily maintenance checklist. Proper daily upkeep can extend the RO membrane lifespan by more than 30%.
I. Pre-Startup Inspection
1. Raw water quality check: Focus on the SDI (Silt Density Index), which must be kept below 5. Excessively high SDI requires enhanced pretreatment to prevent membrane pore blockage.
2. Valve status check: Ensure all valves are in the correct open or closed position to avoid water hammer impact and equipment damage.
3. Pressure gauge check: Verify that raw water pressure, product water pressure and concentrated water pressure are all within the normal range.
II. In Operation Maintenance
1. Control water recovery rate: Operate strictly according to the designed value. Do not blindly increase the recovery rate merely to save water, as this will accelerate membrane scaling.
2. Regular flushing:
• Short shutdown (＜2 hours): Flush immediately after stopping operation to prevent scaling caused by concentrated water on the brine side.
• Long-term shutdown: Soak the membrane with protective solution (such as 1.5% sodium bisulfite solution) to avoid membrane drying and bacterial growth.
3. Monitor pressure differential: When the inlet and outlet pressure difference (ΔP) exceeds 0.07MPa, the membrane surface is heavily contaminated and requires chemical cleaning.
Reverse Osmosis Membrane
III. Chemical Cleaning
Perform CIP cleaning when the water production drops by over 15% or the salt rejection rate decreases by more than 10%:
1. Acid cleaning: Remove inorganic scale such as calcium carbonate and calcium sulfate, commonly using citric acid or hydrochloric acid.
2. Alkaline cleaning: Eliminate organic matter and colloids, generally using sodium hydroxide combined with surfactants.
Note: Strictly control cleaning temperature and concentration to avoid damaging the membrane elements.
IV. Record Keeping & Management
1. Establish operation logs: Record daily water yield, conductivity, operating pressure and other data to detect abnormal fluctuations in a timely manner.
2. Regular sterilization: Disinfect the entire system every 1–3 months to control biofilm growth.
Although daily maintenance of reverse osmosis equipment seems tedious, it is essential for reducing operating costs and ensuring stable effluent quality. Equipment operators are recommended to follow this maintenance checklist strictly and develop standard operating habits. If you encounter any equipment maintenance problems, DIEN Water Treatment provides remote technical guidance and on-site maintenance services. Feel free to contact us anytime.
