Recently, we’ve received numerous orders for ultrafiltration system consumable replacements and annual maintenance of ultrafiltration equipment. During project operations, technicians have identified significant clogging and damage to the ultrafiltration membranes—most of which can be traced back to inadequate daily maintenance and upkeep during equipment use. Today, I’ll summarize the key areas that require regular attention in the day-to-day maintenance of ultrafiltration systems.

　　1. The ultrafiltration pretreatment system should be designed with a flow rate twice that required by the downstream ultrafiltration membrane unit. When performing manual backwashing via the control system, adjust the number and duration of backwash cycles based on the actual water consumption to prevent insufficient water flow due to losses. If the backwashing parameters for the self-contained control system are set by the manufacturer, ensure proper installation. Even during normal operation, regularly monitor and record daily maintenance activities such as water source and power usage. Improper pretreatment can lead to reduced water flow, failure to effectively filter out impurities, and their subsequent entry into the downstream processes—eventually causing filter clogging, which may even result in ultrafiltration membrane blockage, fouling, and damage.

　　2. The filter within the filter should also be replaced promptly—either by yourself or by requesting factory personnel to do it. If filters aren’t replaced regularly, water flow will decrease, impurities won’t get filtered out and will instead enter the downstream processes directly. Over time, this can lead to filter clogging, potentially causing ultrafiltration membranes to become blocked, contaminated, and even damaged.

　　3. It is essential to clean the ultrafiltration membrane promptly. First, you need to identify the right timing for cleaning. When the ultrafiltration system is operating normally, if the production output drops to an unacceptable level, start by checking whether the water pressure at the inlet and outlet of the ultrafilter remains within the normal range. Ultrafiltration is a pressure-driven membrane separation technology, and maintaining adequate pressure is critical for its proper functioning. Typically, monitor the pressure drop across the ultrafiltration unit’s inlet and outlet. If the pressure drop exceeds the initial value by more than 0.05 MPa, it usually indicates a significant increase in fluid resistance. As part of routine maintenance, you can apply an equal-pressure flow-based cleaning method. If this approach proves ineffective, consider employing a combined physical and chemical cleaning technique instead.

　　Ultrafiltration membranes are classified into several structural types, including plate-type (plates), hollow-fiber type, nanomembrane-based ultrafiltration membranes, tubular, and roller designs. Among these, the hollow-fiber ultrafiltration membrane is one of the most mature and advanced forms in ultrafiltration technology. Hollow fibers typically have an outer diameter of 0.4–2.0 mm and an inner diameter of 0.3–1.4 mm, with micropores evenly distributed throughout the fiber wall. The pore size corresponds to the molecular weight of substances that can pass through—ranging from a few thousand to hundreds of thousands of Daltons. Raw water is either pressurized to flow across the outer surface of the hollow fibers or injected into their internal cavities, resulting in either external-pressure or internal-pressure hollow-fiber ultrafiltration systems, respectively. Ultrafiltration is a dynamic filtration process: retained particles are continuously removed along with the concentrated solution, allowing the system to operate efficiently over extended periods without clogging the membrane surface.

　　By performing the three daily maintenance and management tasks outlined above, the ultrafiltration equipment can significantly extend its typical lifespan. However, managing fouling and cleaning the ultrafiltration membrane is a complex process—details on this will be provided in the following article. We hope this information proves useful for our valued users.

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