Water with a specific resistance of 18.3 megohm-cm at 25°C.

(1) A substance that can react with a base to form a salt. 

(2) A substance which can donate a hydrogen ion, or proton.

The capacity of an aqueous solution to neutralize a base.

The volume of water that would cover a one acre area one foot deep. Equivalent to approximately 1,233.6 m³ or 325,900 gallons.

A condenser installed as the last stage of an evaporator venting system to minimize atmospheric steam discharge.

Acre-foot per year.

Water having corrosive qualities.

Agressivity index.

The ability of a water to neutralize an acid due to the presence of carbonate, bicarbonate and hydroxide ions.

(Å) A unit of measure equivalent to one ten thousandth of a micron.

See “calcium sulphate”.

A negatively charged ion that migrates to the anode when an electrical potential is applied to a solution.

An ion exchange process in which anions in solution are exchanged for other anions bound to an ion exchange resin or medium.

The positive electrode where current leaves an electrolytic solution.

A solution in which water is the solvent.

A subsurface geological formation containing a large quantity of water.

A staged arrangement of membrane elements and pressure vessels in a system.

Membranes that are not reversible, and can only desalinate efficiently in one direction.

(1) The gaseous region that surrounds the earth. 

(2) A unit of pressure equal to 1.0333 kg/sq cm, or 14.7 psi. Abbreviated “atm”.