An ultrafiltration device operates as a precise membrane separation process. Hydrostatic pressure forces water and solvents against a semi-permeable membrane with very fine pores. This physical barrier allows water and low-molecular-weight solutes to pass through while blocking suspended solids, bacteria, viruses, and macromolecules (typically in the 10³ – 10⁶ Dalton range).
This process is distinct from microfiltration or nanofiltration primarily by the size of particles it removes. Modern, effective ultrafiltration systems often use back-flushable, air-scoured membranes, with spiral-wound or hollow fiber configurations offering excellent performance for clarifying process and wastewater, frequently eliminating the need for traditional clarifiers and multi-media filters.