Concept of Neutralization Capacity i n Hydrochemistry and Water Technology

Abstract

The neutralization capacity, a quantitative capacity of aqueous media to react with hydrogen of hydroxide ions, is a general property of natural waters, supply waters and waste waters. The acid neutralization capacity (ANC) and the base neutralization capacity (BNC) must be considered. In most natural and supply waters, acid-base systems other than the aqueous ones can be often neglected but in some special cases other buffering substances are also included in the determination. The pH values of the titration endpoint may be chosen from the analytical point of view (pH of the equivalence point) or from the point of view of technology (e.g., the pH-value of the neutralization of waste waters, pH value of the precipitation of metal ions). The pH value chosen is denoted by a subscript in the abbreviation ANCpH or BNCpH (e.g., ANC4. 5, ANC7.0). The neutralization capacity is a general term precisely defined by the chosen pH value replacing different special terms, e.g. total alkalinity, composite alkalinity, carbonate alkalinity, p-alkalinity, m-alkalinity, total acidity, C0₂-acidity, mineral acidity, etc.