What is the typical hardness level achievable by chemical precipitation treatment?

Chemical precipitation treatment is an effective method for reducing water hardness, primarily by removing calcium and magnesium ions through the addition of chemicals that react with these minerals and form insoluble precipitates. This method often involves adding lime (calcium hydroxide) or soda ash (sodium carbonate), which facilitates the reaction that leads to precipitation and subsequent removal of hardness-causing ions.

In practice, chemical precipitation can typically reduce hardness levels down to approximately 35 mg/L as CaCO3. This level is considered achievable in many water treatment scenarios, making it a common target in managing mineral content in drinking water. The effectiveness of the treatment can depend on various operational factors, including the chemicals used, their dosages, and the conditions under which the treatment occurs.

Achieving zero hardness is not practical through this method alone, as some hardness ions may remain soluble or may not be completely removed, while higher concentrations, such as 80 mg/L or 100 mg/L, could reflect the initial hardness level rather than a practical reduction level for chemical precipitation.