Coagulation and flocculation in water treatment are primarily used to:

Coagulation and flocculation in water treatment are primarily used to:

• A. Remove suspended materials from water; commonly used for surface water; floc forms and passes to next tank; larger floc forms and settles
• B. Kill pathogens with disinfectants
• C. Increase taste and odor by adding minerals
• D. Improve color by adding dyes

Answer: (A)

Coagulation and flocculation are about removing suspended materials from water by turning tiny, dispersed particles into larger clumps that can settle out or be filtered. When surface water contains lots of colloids and fine particles with a negative charge, coagulants such as alum or iron salts are added to neutralize those charges. This destabilizes the colloids, allowing them to start sticking together during rapid mixing. Gentle, ongoing mixing then helps those initial clusters grow into larger flocs—heavier, more easily settled or filtered—so turbidity is reduced before disinfection and other treatments. This is why the primary purpose is to remove suspended materials; disinfection, taste/odor adjustments, or color changes are handled by other steps or secondary effects, whereas coagulation and flocculation specifically target turbidity-causing particles.

Coagulation and flocculation are about removing suspended materials from water by turning tiny, dispersed particles into larger clumps that can settle out or be filtered. When surface water contains lots of colloids and fine particles with a negative charge, coagulants such as alum or iron salts are added to neutralize those charges. This destabilizes the colloids, allowing them to start sticking together during rapid mixing. Gentle, ongoing mixing then helps those initial clusters grow into larger flocs—heavier, more easily settled or filtered—so turbidity is reduced before disinfection and other treatments. This is why the primary purpose is to remove suspended materials; disinfection, taste/odor adjustments, or color changes are handled by other steps or secondary effects, whereas coagulation and flocculation specifically target turbidity-causing particles.