The removal of dissolved inorganic solids (salts) from a solution to make it free of dissolved salts.

The removal of ionized minerals and salts from a solution using a two-phase ion exchange procedure.

The removal of excess or free chlorine from a water supply by adsorption with activated carbon or by catalytic type filter media.

A process for the reduction of alkalinity in a water supply. It is generally accomplished by a chemical feed processor combined cation and anion exchange systems.

A complete course of ion exchange operation. For instance, a complete cycle of cation exchange would involve: regeneration of the resin, rinse to remove excess regenerant, exhaustion, backwash, and finally regeneration again.

A microorganism commonly found in lakes and rivers which is highly resistant to disinfection. Cryptosporidium has caused several large outbreaks of gastrointestinal illness, with symptoms that include diarrhea, nausea, and/or stomach cramps. People with severely weakened immune systems (that is, severely immuno-compromised) are likely to have more severe and more persistent symptoms than healthy individuals.

The addition of any physical, chemical, biological or radiological substance to water which reduces the value of the water, or interferes with its intended use.

Anything found in water (including microorganisms, minerals, chemicals, radionuclides, etc.) which may be harmful to human health.

A group of related bacteria whose presence in drinking water may indicate contamination by disease-causing microorganisms.

The possible result of exposure over many years to a drinking water contaminant at levels above its MCL.