filtration, the process in which solid particles in a liquid or gaseous fluid are removed by the use of a filter medium that permits the fluid to pass through but retains the solid particles. Either the clarified fluid or the solid particles removed from the fluid may be the desired product.

What is the purpose of a filter?

A filter is a device or process that removes something from a signal. The complete or partial suppression of some aspect of the signal is the defining feature of filters.

How do filters work?

First, the large internal surface area physically traps sediments and contaminants. Then, activated carbon acts like a magnet for compounds like lead and volatile organic compounds as water passes through. Finally, chemical reactions inside the filter reduce chemicals like chlorine on contact.