Ultrafiltration is a process of separating suspended particles from liquid. The process relies on the use of a membrane that has tiny pores. The liquid is forced through the membrane, leaving the solids behind. Alternative terms to describe this process include "selective permeation," "tangential filtration," or "high molecular weight filtration." The process is used in various applications, such as water treatment, food processing, and pharmaceuticals. Other terms associated with ultrafiltration include "microfiltration," "nanofiltration," and "reverse osmosis." Each term describes a specific variation of this filtering technique, based on the size of particles that can pass through the membrane. Ultimately, though, they share the goal of removing impurities and producing a pure liquid product.