Total Hardness can be expressed as the sum of which two forms?

Total hardness in water is primarily a measure of the concentration of calcium and magnesium ions. It is commonly divided into two components: carbonate hardness and non-carbonate hardness.

Carbonate hardness refers to the hardness contributed by bicarbonate and carbonate ions. This form of hardness can be managed through processes such as lime softening, which precipitates the calcium and magnesium as insoluble salts.

Non-carbonate hardness, on the other hand, is due to the presence of sulfates, chlorides, and other salts of calcium and magnesium. This type of hardness does not precipitate readily and is not easily removed through lime treatment.

Understanding the distinction between these two forms of hardness is crucial for water treatment processes, as it influences how different treatment methods are applied to achieve desired water quality. Defining hardness in this manner helps water operators assess treatment needs effectively and understand the implications of water hardness on both industrial processes and drinking water quality.