What type of media is typically used in drinking water filtration?

• A. Sand/anthracite filters
• B. Chloramines
• C. Alum
• D. Ferric chloride

Answer: (A)

In drinking water filtration, the media are the materials the water passes through to remove particles. A common setup uses a multi-media bed with an upper layer of anthracite and a lower layer of sand. The anthracite is lighter and has larger pores, so it traps bigger particles and provides good flow. The sand below catches smaller particles, delivering a final polishing step to reduce turbidity. This layered approach improves filtration efficiency and flow stability compared with a single medium. Chloramines are disinfectants added after filtration to maintain residual protection, not filtration media. Alum and ferric chloride are coagulants used earlier in the treatment process to clump tiny particles so they settle more easily, rather than serving as the filtration material. So the typical media used in filtration is sand and anthracite.