In water treatment, lime is commonly supplied as which compound?

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Multiple Choice

In water treatment, lime is commonly supplied as which compound?

Lime used in water treatment is typically delivered as calcium oxide (quicklime). This form is stable for shipping and storage, making it the common supply form. On site, it’s hydrated with water to form calcium hydroxide, which is the active lime used for pH adjustment and softening. The hydration reaction CaO + H2O → Ca(OH)2 is what creates the usable lime slurry. Calcium carbonate is a product that can form later in treatment, and calcium hydroxide is the hydrated form produced from calcium oxide, while sodium hydroxide is a different chemical altogether.

Lime used in water treatment is typically delivered as calcium oxide (quicklime). This form is stable for shipping and storage, making it the common supply form. On site, it’s hydrated with water to form calcium hydroxide, which is the active lime used for pH adjustment and softening. The hydration reaction CaO + H2O → Ca(OH)2 is what creates the usable lime slurry. Calcium carbonate is a product that can form later in treatment, and calcium hydroxide is the hydrated form produced from calcium oxide, while sodium hydroxide is a different chemical altogether.

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