dual-media filter

A dual-media filter is a type of filter used in water treatment that employs two distinct layers of filter media to remove impurities. Typically, this involves a top layer of anthracite coal above a layer of fine sand. The coarser anthracite traps larger suspended particles and floc, while the finer sand below captures smaller impurities. This "in-depth filtration" allows impurities to be trapped throughout the filter bed, not just on the surface, enhancing efficiency.1

Filtration, in general, is a process that separates solid particles from a liquid or gas using a filter medium that allows the fluid to pass but retains the solids. This technique is fundamental in purifying water for consumption and in various industrial chemical processes.21