a measure of the amount of finely divided suspended matter in water, which causes the scattering and absorption of light rays.
an element often found dissolved in ground water in concentrations usually ranging from zero to 10 ppm. It is objectionable in water supplies because of the staining caused after oxidation and precipitation, because of taste, and because of unsightly colors produced when iron reacts with tannins in beverages such as coffee and tea.
a characteristic of natural water due to the presence of dissolved calcium and magnesium; water hardness is responsible for most scale formation in pipes and water heaters, and forms insoluble" curd" when it reacts with soaps. Hardness is usually expressed in grains per gallon, parts per million, or milligrams per liter, all as calcium carbonate equivalent.
a gas, widely used in the disinfection of water and an oxidizing agent for organic matter, iron, etc.
The process in which beds of filter or ion exchange media are subjected to flow opposite to the service flow direction to loosen the bed and to flush suspended matter, collected during the service run, to waste.