WC&P is proud to offer this comprehensive glossary to our readers and website visitors. This living document is intended to serve as an easy-to-use reference source for information on the POU/POE water treatment industry.
Any suggestions or input that would further enhance or expand the glossary are strongly encouraged.
We would like to formally thank and credit such organizations as WQA, AWWA, WEF, Lenntech and other web glossary sources for providing some of the basis and background of this compendium.
Langelier index (LI)
An index reflecting the equilibrium pH of a water with respect to calcium and alkalinity; used in stabilizing water to control both corrosion and scale deposition. A calculated number that gives and indication of the tendency of water to form a protective film of calcium carbonate scale, to dissolve it or be in equilibrium with it. It does not take into account the quantities of film formed, the effect of velocities, oxygen, carbon dioxide, ammonia, silicon or natural inhibitors in the water. Therefore, it is sometimes erroneously assumed that any water that tends to dissolve calcium carbonate is automatically corrosive. A calculated number used to predict whether or not a water will precipitate, be in equilibrium with, or dissolved calcium carbonate. It is sometimes erroneously assumed that any water that tends to dissolve calcium carbonate is automatically corrosive.