mixed-media filter

A mixed-media filter is a type of filter used in water treatment that employs multiple layers of different granular materials to remove impurities. These layers, typically consisting of anthracite coal, sand, and garnet, are arranged in descending order of grain size and density. This design allows for in-depth filtration, where larger particles are trapped in the upper layers, and smaller particles are captured in the finer layers below. This method is more effective than single-media filters, especially for water with significant turbidity, as it prevents the filter bed from becoming clogged too quickly.1

The process begins after initial steps like coagulation and flocculation, where suspended particles clump together. Filtration then removes the remaining non-settling impurities, making the water clear and free of harmful protozoa. When the filter media becomes clogged, it is cleaned through a process called backwashing, where clean water is forced upward through the filter to remove trapped particles.1