The hardness of industrial water in Xi'an is relatively high, with high levels of calcium and magnesium ions in both well water and tap water. DIEN Water Treatment has worked with many local factory clients, and numerous companies have experienced problems with their RO (reverse osmosis) equipment due to a lack of proper cleaning over a long period. These problems include decreased water production, reduced desalination rates, and soaring membrane pressure differentials (click to learn more: Standard Reference for High and Low Operating Pressure of Reverse Osmosis Equipment). A standardized, regular cleaning program for RO equipment can restore the performance of membrane elements, significantly extend the lifespan of the RO membrane, and reduce equipment replacement costs. Below is a detailed explanation of the entire chemical cleaning process for RO reverse osmosis equipment for clients in various industries in Xi'an.
Reverse Osmosis Equipment
I. RO Reverse Osmosis Equipment Cleaning Determination Cycle and Triggering Conditions
Adapting to the water quality characteristics of surface water and groundwater in Xi'an, DIEN Water Treatment has established a fixed maintenance cycle. Under normal operating conditions, the RO reverse osmosis equipment undergoes preventative chemical cleaning every 5 to 6 months. For well water sources and high-water-load plants such as food and pharmaceutical plants, the cycle is shortened to a deep cleaning every 3 months.
When the following data changes occur: a system pressure difference increase exceeding 0.15 MPa, a decrease in permeate flow of 10%, and a decrease in desalination rate of 3%, the RO reverse osmosis equipment needs to be immediately shut down for cleaning. In routine operations, low-pressure physical flushing is performed weekly with permeate water to preemptively remove loose colloids, thereby reducing the frequency of chemical cleaning.
II.Standard chemical cleaning steps for RO reverse osmosis equipment
The cleaning process should follow the sequence of alkaline washing, followed by rinsing with clean water, and then acid washing to solidify the residue. Reversing this order will cause contaminants to solidify, rendering the cleaning ineffective.
Through alkaline circulating cleaning, the cleaning solution is first prepared using RO permeate. The pH is then adjusted to a range of 10 to 12. The water temperature is controlled between 25 and 35°C, and the solution is circulated at a low pressure of 0.15 to 0.3 MPa for 60 minutes. A 30-minute soaking period is then included to decompose biofilm, oil, and colloidal contaminants, thus addressing the common microbial slime problem encountered by the Xi'an Well Water Institute.
After alkaline washing, continuously circulate the water produced by the RO system until the pH of the output water returns to a neutral range of 6.5 to 7.5. It is crucial to prevent carbonate precipitation due to acid-base neutralization, which could scratch the membrane elements.
RO Reverse Osmosis Equipment
For descaling and cleaning using an acidic method, prepare a citric acid cleaning solution with a pH maintained between 2 and 3. Circulate for 40 minutes. This method is specifically designed to remove high levels of calcium carbonate and calcium sulfate scale caused by the characteristics of Xi'an's water quality. For severe scaling, the soaking time can be extended.
Upon completion and finalization, a rinsing operation is performed before production begins: After acid washing, a second rinsing operation is conducted at a high flow rate to thoroughly remove all chemicals. The RO reverse osmosis equipment is then turned on and run unloaded for 30 minutes. The initially produced water undergoes a discharge treatment process. Once the water quality stabilizes, it is then connected to the product water tank. Specific data on pressure difference and conductivity before and after cleaning are recorded to compare the corresponding effectiveness.
III. Key Points for Cleaning RO Reverse Osmosis Equipment in Xi'an
Tap water must never be used to prepare cleaning solutions to prevent the introduction of new impurities. The water temperature should not exceed 35℃, as high temperatures will accelerate RO membrane aging. Acid and alkali chemicals should be stored separately and prepared and used immediately. Due to the low winter temperatures in Xi'an, it is best to install a heating device in the cleaning water tank to ensure the chemical reactivity. If the flux recovery after a single cleaning is less than 85%, a second cleaning is necessary. If there is still no improvement, it is determined that the membrane has irreversible fouling. In this case, contact DIEN Water Treatment for on-site inspection and replacement of the membrane elements. DIEN Water Treatment has been deeply involved in the water treatment industry in Xi'an for over ten years. They are able to visit food factories, pharmaceutical plants, and mining areas to customize exclusive RO reverse osmosis equipment regular cleaning and maintenance solutions (click to learn more: 2026 New Version of Reverse Osmosis Equipment Maintenance and Troubleshooting Techniques). They also provide one-stop technical services including on-site chemical cleaning and membrane maintenance. As the original manufacturer, their operation and maintenance quotes are more affordable.
