ABSTRACT
Acidity of water is its quantitive capacity to react with a strong base to a designated pH. Alkalinity of water is its quantitative capacity to react with a strong acid to a designated pH. Total hardness is commonly reported as an equivalent concentration of calcium carbonate hardness in water caused by calcium and magnesium salts. Chloride, in the form of Cl- ion, is one of the major inorganic anions in water and waste water, originated from natural minerals, seawater intrusion, and industrial pollution. Hydrogen sulfide reacts with metals to form insoluble sulfides, and makes corrosivity a problem for all metallic pipes. It has caused serious corrosion of concrete sewers by biologically oxidizing to H2SO4 on the pipe wall. Sulfur and nitrogen oxide gases also form sulfate and nitrate particulates. These may settle out from the atmosphere onto surfaces, as plants and other solid surfaces.
