AWWA JAW27635

Calcium carbonate (CaCO3) saturation indexes are commonly used to evaluate the scale-forming and scale-dissolving tendencies of water. Assessing these tendencies is useful in corrosion-control programs and in preventing CaCO3 scaling in piping and equipment, such as water distribution system appurtenances, industrial heat exchangers, or domestic water heaters. This article is adapted from method 2330, Calcium Carbonate Saturation, which was developed for the 17th edition of Standard Methods for the Examination of Water and Wastewater. Discussed are: measurements that must be taken to calculate the CaCO 3 saturation indexes, limitations of these indexes, indexes that indicate whether a water is oversaturated, saturated, or undersaturated as well as those that indicate the quantity of CaCO 3 that is precipitated or dissolved. A source list of where diagrams and computer codes for these indexes can be obtained is included. Includes 45 references, tables.