AWWA JAW17912

One of the frequently calculated parameters in water stability evaluations and corrosion control practices is the Langelier saturation index. This index was developed to assess the tendency of a water to deposit or dissolve the calcium carbonate coating on pipes. Although this thermodynamic prediction of the tendency for calcium carbonate to precipitate or dissolve through use of the Langelier index is quick and useful, it is sometimes more reliable to determine the actual saturation state of a processed or treated water. Whether a given water will dissolve or precipitate calcium carbonate can be determined experimentally by equilibrating the water with calcium carbonate. This article discusses the results of equilibrium experiments which were conducted to characterize the behavior of pH, alkalinity, and calcium level over time in samples of Gainesville, Florida, tap water and deionized water. Includes 18 references, figures.