Ultrafiltration pure water equipment removes bacteria and viruses from water through a physical sieving mechanism, with the core being the precision filtration function of the ultrafiltration membrane. This equipment utilizes the microporous structure distributed on the membrane surface to form a selective barrier under pressure. When water flows through the membrane module, water molecules and dissolved small molecules, due to their smaller particle size, can pass through, while bacteria, viruses, colloids, and large organic molecules, due to their larger size, are trapped, thus separating water from contaminants. This sieving process requires no chemical reagents and is entirely based on physical action for purification.
The pore size range of ultrafiltration membranes is typically between 0.001 and 0.02 micrometers, a scale far smaller than the diameter of most bacteria (approximately 0.2-10 micrometers) and viruses (approximately 0.02-0.3 micrometers). When water flows through the membrane surface, microorganisms are mechanically intercepted by the membrane pores and cannot penetrate to the product water side. Although some viruses may approach the upper limit of the membrane pore size, the three-dimensional network structure of the ultrafiltration membrane further enhances the interception effect through adsorption. Furthermore, the dynamic shear force of the water flow formed on the membrane surface can inhibit the adhesion of microorganisms to the membrane, reducing the possibility of biofilm formation.
During equipment operation, pressure drive is the key power source. Tap water or raw water enters the ultrafiltration membrane module under the action of a booster pump, and the pressure difference promotes the directional migration of water molecules. In the internal pressure membrane structure, water flows from the inside of the membrane fibers to the outside, and pollutants are trapped on the inner wall of the membrane tube; in the external pressure type, filtration is achieved through external pressure on the membrane fibers, and pollutants accumulate on the membrane surface. Both structures maintain membrane flux stability through a periodic backwashing program, using reverse water flow to flush away the trapped material on the membrane surface. Some equipment is also equipped with a cross-flow filtration system, which reduces pollutant deposition through high-speed water flow flushing.
The filtration precision of ultrafiltration pure water equipment makes it an effective technology for removing bacteria and viruses. Compared with traditional filtration methods, its advantage lies in achieving highly efficient sterilization without high temperature or chemical disinfection. For example, intestinal pathogens such as E. coli, due to their large size, can be completely trapped by ultrafiltration membranes; although viruses are small, most virus particles are removed due to adsorption on the membrane surface or steric hindrance. Studies have shown that compliantly designed ultrafiltration systems can achieve a bacterial removal rate of up to 99.99% and a virus removal rate that meets drinking water safety standards.
The choice of membrane material directly affects equipment performance. Polyvinylidene fluoride (PVDF) and polyethersulfone (PES) are mainstream membrane materials due to their oxidation resistance and antifouling properties. These materials form an asymmetric membrane structure through phase inversion processes, with a dense surface layer for precise sieving and a porous bottom support layer to ensure water flow. Some equipment uses modified PVC membranes, which enhance antifouling capabilities through hydrophilic modification, extending membrane life to 3-5 years.
In practical applications, ultrafiltration pure water equipment is often used in conjunction with other technologies to improve overall treatment efficiency. A pre-filter (quartz sand filter) removes large suspended solids and protects the ultrafiltration membrane from mechanical damage; a post-filter (activated carbon adsorption unit) further improves water taste and removes residual organic matter. In municipal water supply, ultrafiltration equipment, as a deep treatment process, can replace traditional sand filtration + disinfection processes. In the industrial sector, its modular design supports on-demand expansion to meet the high-purity water requirements of industries such as food and beverage, pharmaceuticals, and electronics.
Maintenance and management are crucial for ensuring the long-term stable operation of the equipment. Regular chemical cleaning dissolves organic matter adsorbed on the membrane surface, alkaline cleaning agents remove oily contaminants, and acidic cleaning agents target inorganic salt scaling. Intelligent monitoring systems automatically trigger cleaning procedures by monitoring parameters such as transmembrane pressure differential and permeate flow in real time, preventing performance degradation caused by membrane fouling. A well-designed pretreatment system and standardized operation and maintenance procedures ensure that ultrafiltration pure water equipment continuously provides a safe and reliable drinking water source.
