Depending on the quality of the feed water, and the final quality of water desired a variety of chemicals, or, no chemicals at all might apply. However, as a general block of information here though are some common chemicals that get used to purify water.
- Chlorine is used as an oxidizing agent to cause iron to precipitate and be filtered.
- Both Chlorine and Chloramine are used to kill bacteria, viruses and other organisms.
- Iron, in the form of Ferric Sulfate and Ferric Chloride is used to flocculate sediment into large particles that can be mechanically filtered out.
- Aluminum compounds such as Aluminum Chloro-hydrate, Aluminum Sulfate and Poly-Aluminum Chloride are also used as flocculants
- Hydrochloric, Citric, and Sulfuric acids may be used to lower the pH of highly alkaline water
- Sodium Hydroxide or (NaOH) may be used to Raise the pH of acidic water. Calcium Hydroxide, or Calcium Chloride may also be used
- Ozone and Hydrogen may be used to kill bacteria
- Sodium may be used in water softening where high-hardness calcium scale is problematic