What type of filtration uses sand as its primary medium?

The type of filtration that utilizes sand as its primary medium is gravity filtering. This method involves allowing water to pass through layers of sand and other media, relying on gravity to draw the water down through the filter bed. As the water flows through the sand, particles and impurities are trapped, effectively removing them from the water.

Gravity filters are commonly used in municipal water treatment processes because they are simple to operate and can handle large volumes of water. The effectiveness of this filtration system is due to the physical properties of sand, such as its size and shape, which create spaces for water to flow while capturing contaminants.

In contrast, other methods such as centrifugal filtering, pressure filtering, and membrane filtering utilize different principles and materials. Centrifugal filtering applies a rotating motion to separate solids from liquids, pressure filtering uses applied pressure to push liquid through a filter medium, and membrane filtering relies on semi-permeable membranes to separate components based on size. Each of these methods serves specific purposes and is chosen based on the characteristics of the water being treated and the desired level of filtration.