Glossary Of Water Treatment Industry Terms . . . "G"
Gallionella ferruginea - A genus of stalked,
ribbon-like bacteria which utilize iron in their metabolism, and cause
staining, plugging and odor problems in water systems. (See iron bacteria.)
gallon - A unit of liquid volume; the
U.S. gallon has a volume of 231 cubic inches or 3.78533 liters; the
British (Imperial) gallon has a volume of 277.418 cubic inches or 4.54596
galvanic cell - A cell which generates
an electrical current, consisting of dissimilar metals in contact with
each other and with an electrolyte.
galvanic corrosion - The form of
corrosion which occurs in a galvanic cell, in which one of the metals
goes into solution; accelerated by high concentrations of dissolved
minerals in water, which increases the electrical conductance; and elevated
temperatures. (See corrosion, electrolyte.)
gate valve - A valve with the closing
element that is a disc which is moved across the stream, often in a
groove or slot, for support against pressure.
gel zeolite- A synthetic sodium aluminoscilicate
Giardia Lamblia - An intestinal parasite
commonly found in water supplies originating in mountainous or wooded
watersheds. It exists as a free-swimming protozoan-like organism in
warm-blooded animals' intestines, causing chronic diarrhea, cramps,
bloating and weight loss. Outside of the intestines, it forms a tough
cyst that protects it until it finds a new host. Resistant to chlorine
and most oxidizing agents, Giardia can be removed effectively through
filtration below 1 micrometer.
globe valve - A valve in which the
closing element is a sphere, or a flat or rounded gasket, which is moved
into or onto a round port.
gpg - Abbreviation for "grain(s) per
grab sample - A single sample of
material collected at one place and one time.
grain(gr.) - A unit of eight equal to 1/7000th
of a pound, or 0.0648 gram.
grain(s) per gallon (gpg) - A common basis for reporting water analyses in the United States and Canada; one grain per U.S. gallon equals 17.12 milligrams per liter (mg/l) or parts per million (ppm). One grain per British (Imperial) gallon equals 14.3 milligrams per liter or parts per million.
gram (g) - The basic unit of weight (mass)
of the metric system, originally intended to be the weight of 1 cubic
centimeter of water at 4oC. (One pound is 454 grams.)
gram-milliequivalent- The equivalent
weight of a substance in grams, divided by one thousand.
gravimetric- Measurement of matter on the
basis of weight.
greensand- A natural mineral, primarily
composed of complex silicates, which possess ion exchange properties.
(See manganese greensand, zeolite.)