Alkalinity is defined as the ___________ capacity of a water.

Alkalinity is defined as the ___________ capacity of a water.

• A. Thermal
• B. Oxidizing
• C. Buffering / acid neutralizing
• D. Adsorptive

Answer: (C)

Alkalinity is the water’s ability to resist pH change by neutralizing added acids, i.e., its buffering or acid-neutralizing capacity. This capacity mainly comes from carbonate, bicarbonate, and hydroxide ions and is commonly expressed as mg/L as CaCO3. This buffering keeps pH from dropping too quickly when acids enter the water, which is especially important in wastewater treatments where processes like nitrification consume alkalinity and can lower pH if it’s not enough. The other terms refer to different properties: thermal capacity is about heat storage, oxidizing capacity relates to how much oxidant the water can accept, and adsorptive capacity concerns binding contaminants to surfaces.

Alkalinity is the water’s ability to resist pH change by neutralizing added acids, i.e., its buffering or acid-neutralizing capacity. This capacity mainly comes from carbonate, bicarbonate, and hydroxide ions and is commonly expressed as mg/L as CaCO3. This buffering keeps pH from dropping too quickly when acids enter the water, which is especially important in wastewater treatments where processes like nitrification consume alkalinity and can lower pH if it’s not enough. The other terms refer to different properties: thermal capacity is about heat storage, oxidizing capacity relates to how much oxidant the water can accept, and adsorptive capacity concerns binding contaminants to surfaces.