Glossary of Terms - Z
A B C D E F G H I J K L M N O P Q R S T U V W Z
zeolites - Hydrated sodium alumina silicates, either naturally-occurring mined products or synthetic products, with ion exchange properties. Zeolites were formerly used extensively for residential and commercial water softening but have been largely replaced by synthetic organic cation resin ion exchangers of polystyrene divinylbenzene substrate. Modified zeolites such as manganese greensand and synthetic manganese zeolites are still used as catalyst/oxidizing filters for the removal of iron, hydrogen sulfide, and manganese. (See gel zeolite, greensand.)
zeolite softening - A term formerly used for the removal of calcium and magnesium hardness from water by base exchange using natural or synthetic zeolites. Since the introduction of synthetic organic cation exchange resins, the more correct term is cation exchange softening. Zeolite softening was also called base exchange.
zero soft - Water produced by the cation exchange process and measuring less than 1.0 grain per U.S. gallon (17.1 ppm or 17.1 mg/L) as calcium carbonate.
zone of aeration - The comparatively dry soil or rock located between the ground surface and the top of the water table.
zone of saturation - The layer in the ground in which all available interstitial voids (cracks, crevices, holes) are filled with water. The level of the top of this zone is the water table.