ABSTRACT

The alkalinity of water is its quantitative capacity to react with a strong acid to a designated pH. Alkalinity is a measure of an aggregate property of water and can be interpreted in terms of specific substances only when the chemical composition of the sample is known. The measured value of the alkalinity of water may vary significantly with the end point pH used, and is primarily the function of carbonate, bicarbonate, and hydroxide content. The pH at which water is saturated with calcium carbonate is known as the pH of saturation. Calculation of the saturation index (SI) is based on the values of pH, total alkalinity as Calcium Carbonate, total dissolved solids (TDS), temperature, and total hardness as Calcium Carbonate. A positive index is associated with noncorrosive conditions, whereas a negative index indicates the possibility of corrosion. Toxic metals such as lead and cadmium are corrosion products from lead and galvanized pipes.