All about Water: Basic Concepts - The Drinking Water - page 17

Disinfectants and disinfection byproducts (DBPs)— A term used in connec-
tion with state and federal regulations designed to protect public
health by limiting the concentration of either disinfectants or the
byproducts formed by the reaction of disinfectants with other sub-
stances in the water (such as trihalomethanes, THMs).
Disinfection— A chemical treatment method; the addition of a substance
(e.g., chlorine, ozone, hydrogen peroxide) that destroys or inactivates
harmful microorganisms or inhibits their activity.
Dissociate— The process of ion separation that occurs when an ionic
solid is dissolved in water.
Dissolved oxygen (DO)— The oxygen dissolved in water, usually
expressed in milligrams per liter, parts per million, or percent of
saturation.
Dissolved solids— Any material that can dissolve in water and be recov-
ered by evaporating the water after filtering the suspended material.
Drinking water standards— Water quality standards that must be met in
terms of suspended solids, unpleasant taste, and microbes harmful
to human health. Drinking water standards are included in state
water quality rules.
Drinking water supply— Any raw or finished water source that is or may
be used as a public water system or as drinking water by one or
more individuals.
Effluent limitations— Standards developed by the U.S. Environmental
Protection Agency (EPA) to define the levels of pollutants that could
be discharged into surface waters.
Electrodialysis— The process of separating substances in a solution by
dialysis, using an electric field as the driving force.
Electronegativity— The tendency for atoms that do not have a complete
octet of electrons in their outer shell to become negatively charged.
Enhanced Surface Water Treatment Rule (ESWTR)— A revision of the orig-
inal Surface Water Treatment Rule that includes new technology and
requirements to deal with newly identified problems.
Facultative bacteria— A type of anaerobic bacteria that can metabolize its
food either aerobically or anaerobically.
Federal Water Pollution Control Act (1972)— The objective of the Act was
“to restore and maintain the chemical, physical, and biological integ-
rity of the nation's waters.” This Act and subsequent Clean Water Act
amendments are the most far-reaching water pollution control leg-
islation ever enacted. They provide for comprehensive programs for
water pollution control, uniform laws, and interstate cooperation, as
well as grants for research, investigation, training, surveillance, and
gathering information on the effects of pollutants, pollution control,
and the identification and measurement of pollutants. Additionally,