Filtracija

Filtracija is a separation process in which a mixture is passed through a porous medium that retains suspended solids while allowing fluid to pass. The retained material may form a filter cake, and the driving force can be gravity, pressure, or vacuum. Filtracija is widely used in water treatment, food processing, and industry.

Filtration relies on size exclusion and interactions with the filter medium. It is commonly described as depth filtration, where particles are trapped throughout the medium, and surface filtration, where they are retained at the surface. Additional mechanisms include adsorption of dissolved substances and, in some systems, biological removal.

Membrane filtration uses thin barriers with defined pore sizes. Categories include microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, each restricting different solutes. Common media include sand or cloth for bulk filtration and activated carbon or polymeric membranes for finer separations.

Applications span drinking-water purification, municipal and industrial wastewater treatment, food and beverage processing, pharmaceutical manufacturing, and air filtration. Filtration is often combined with pretreatment, chemical treatment, and post-treatment steps to ensure product quality and process efficiency.

Key considerations include media selection, pore size or cut-off, flow rate, fouling and cleaning, energy use, and cost. Choice of method depends on target contaminants, required purity, and operational constraints. Filtracija has evolved from simple cloth filters to advanced membrane technologies.