INTRODUCTION Ultrafiltration is a water purification process that can be used to remove particulates and macromolecules from raw water to produce drinking water. They were used to replace existing secondary (coagulation, flocculation, sedimentation) and tertiary (sand filtration and chlorination) filtration systems used in water treatment plants. When treating water with a high suspended solids content, UF is often integrated into the process, using primary treatments (screening, flocculation and filtration) and some secondary treatments as pretreatment steps. Ultrafiltration processes are currently preferred over traditional treatment methods for the following reasons: • No chemicals required (other than cleaning) • Consistent product quality regardless of feed quality • Compact plant size • Capable of exceed regulatory water quality standards, achieving 90-100% pathogen removalCASE STUDYThe use of the ultrafiltration process is currently being used at the Twin Oaks Valley Water Treatment Plant in San Diego County. Three million San Diego County residents currently receive drinking water from the Southern California Metropolitan Water District (MWD), which treats the water at one of its water treatment plants. But growth in the area has outpaced the water district's ability to provide sufficient quantities of water during the summer season. The Twin Oaks Valley Water Treatment Plant helps mitigate any water shortages and also provides a self-sustaining, cost-effective, high-quality supply that meets the area's demands. The Zee Weed ultrafiltration system does not require the need for heavy and space-consuming pretreatment systems such as coagulation and flocculation specified in the convent... middle of paper... raw water enters the leaves as water high quality drinking water and therefore guarantees the elimination of waste and by-products. Disadvantages of Ultra FiltrationUltra Filtration processes are limited by high costs incurred due to fouling and membrane replacement. Further pre-treatment of the feed water is required to avoid excessive damage to the membrane units. The water treatment plant is not yet affected by this problem, but pretreatment may be necessary in the near future considering the durability of the ultrafiltration membrane. Conclusion The use of the ultrafiltration unit at the San Diego County Water Treatment Plant has helped the county in several ways, as discussed above. The water flowing into the river contained a certain amount of solid substances and a necessary amount of microbiological particles which also helped to encourage the use of the ultrafiltration process.