Which parameter helps stabilize pH during treatment and aids coagulation?

Which parameter helps stabilize pH during treatment and aids coagulation?

• A. Hardness
• B. Chlorine residual
• C. Alkalinity
• D. Temperature

Answer: (C)

Buffering capacity in the water, provided by alkalinity, keeps pH from changing as acids or bases are added during treatment. Alkalinity comes mainly from carbonate and bicarbonate ions, which neutralize added hydrogen ions produced during coagulation. When alkalinity is sufficient, the pH stays in the range where coagulants work best, allowing particles to form flocs that settle out more effectively. That’s why alkalinity is the key parameter for stabilizing pH and aiding coagulation. Hardness relates to calcium and magnesium minerals and doesn’t buffer pH, chlorine residual is for disinfection, and temperature affects reaction rates but not pH stability in the same way.

Buffering capacity in the water, provided by alkalinity, keeps pH from changing as acids or bases are added during treatment. Alkalinity comes mainly from carbonate and bicarbonate ions, which neutralize added hydrogen ions produced during coagulation. When alkalinity is sufficient, the pH stays in the range where coagulants work best, allowing particles to form flocs that settle out more effectively. That’s why alkalinity is the key parameter for stabilizing pH and aiding coagulation. Hardness relates to calcium and magnesium minerals and doesn’t buffer pH, chlorine residual is for disinfection, and temperature affects reaction rates but not pH stability in the same way.