Which filter type uses stacked discs with narrow gaps to remove particles?

• A. Screen Filter
• B. Media Filter
• C. Disc Filter
• D. UV Filter

Answer: (C)

Disc filters rely on a stack of closely spaced filter discs with narrow gaps between them. As water passes through, particles larger than those tiny gaps get trapped on the disc surfaces and in the small channels between discs, creating a highly efficient physical barrier in a compact footprint. The design provides a large filtration area, which helps capture fine particles and maintain flow. When debris builds up, the filter is backwashed—flow is reversed and sometimes aided by air scour—to lift and flush the captured solids out, restoring clean flow.

Screen filters use a mesh or screen to block particles bigger than the opening, but can clog the screen itself. Media filters rely on a bed of granular material (like sand or coal) to trap particles as water moves through the depth of the media. UV filters don’t remove particles; they disinfect water by exposing microorganisms to ultraviolet light.