What process involves adding CO2 to water?

The process of adding CO2 to water is known as recarbonation. This is a significant step in water treatment systems, particularly in the context of reintroducing carbon dioxide to water, often after it has undergone decarbonation. The goal of recarbonation is to maintain proper pH levels and improve the taste of the water, as well as to ensure that minerals such as calcium and magnesium are kept in solution, which can be beneficial to the water quality.

In various water treatment processes, particularly those aimed at softening water, decarbonation would remove carbon dioxide and the alkalinity of water. Therefore, recarbonation is counteractive to that process, as it replenishes CO2 levels. This balance is crucial for effective water treatment and ensuring the stability of the water's chemistry over time.