Glossary of Terms

Abbreviation for American National Standards Institute.

Batch Operation
The utilization of ion exchange resins to treat a solution in a container wherein the removal of ions is accomplished by agitation of the solution and subsequent decanting of the treated liquid.

A mass of ion exchange resin particles or filter media contained in a column.

Bed Depth
The height of the resin or filter media in the column after it has been properly conditioned for effective operation, usually expressed in inches. This depth excludes any supporting bed.

Bed Expansion
The effect produced during backwashing: the resin particles become separated and rise in the column. The expansion of the bed due to the increase of the space between resin particles may be controlled by regulating backwash flow.

A strong solution of salt(s), such as the sodium chloride or potassium brine used in the regeneration of ion exchange water softeners, but also applied to the mixed sodium, calcium and magnesium chloride waste solution from regeneration.

Brine Tank
A tank which sits beside the softening unit (resin tank) and acts as a salt storage and brine supply. The brine tank may also contain the resin tank.

In a softener or deionizer it is the adsorption activity possessed in varying degree by ion exchange materials. This quality may be expressed as kilograins per cubic foot, gram-milliequivalents per gram, pound-equivalents per pound, gram-milliequivalents per milliliter, etc., where these ratios represent the weight of the ions adsorbed and the denominators, the weight or volume of the adsorbent. It can also refer to the ability of any media to take up a specific contaminant and is rated by time over gallons. As to flow rates, it is the maximum or minimum flow obtainable under given conditions of media, temperature, pressure, velocity, etc.

Control Valve
Valve which controls the flow of water through a water conditioning system.

The removal of the ionized minerals and salts (both organic and inorganic) from a solution by a two-phase ion exchange procedure. First, positively charged ions are removed by a cation exchange resin in exchange for a chemically equivalent amount of hydrogen ions. Second, negatively charged ions are removed by an anion exchange resin for a chemically equivalent amount of hydroxide ions. The hydrogen and hydroxide ions introduced in this process unite to form water molecules. The term is often used interchangeably with demineralization. The cation resin is regenerated with an acid and the anion resin is regenerated with sodium hydroxide (caustic soda).

The effectiveness of the operational performance of an ion exchanger. Efficiency in the adsorption of ions is expressed as the quantity of regenerant required to effect the removal of a specified unit weight of adsorbed material, e.g., pounds of acid per kilogram of salt removed.

Exchange Sites
Locations on ion exchange resin beads which hold mobile ions that are available for exchange with other ions in a solution passing through the bed. These sites are also called functional groups.

Exchange Velocity
The rate with which one ion is displaced from an exchanger in favor of another.

A common unit of liquid volume; the US 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 liters.

Grain (gr)
A unit of weight equal to 1/7000th of a pound or 0.0648 gram.

Grains Per Gallon (GPG)
An expression of concentration of material in solution. One grain per gallon is equivalent to 17.1 parts per million. This is the common reference for hardness of water.

A characteristic of natural water due to the presence of dissolved calcium and magnesium; water hardness is responsible for most scale formation in pipes and water heaters, and forms insoluble “curd” when it reacts with soaps. Hardness is usually expressed in grains per gallon, parts per million, or milligrams per liter, all as calcium carbonate equivalent. Temporary hardness, caused by the presence of magnesium of calcium bicarbonate, is so called because it may be removed by boiling the water to convert the bicarbonates to the insoluble carbonates. Calcium sulfate, magnesium sulfate, and the chlorides of these two metals cause permanent hardness.

Hard water
Water with a total hardness of one grain per gallon or more, as calcium carbonate equivalent.

The act of triggering a regeneration cycle. Timer Initiation triggers a regeneration at regular intervals based upon a clock setting. Meter Initiation saves water, salt, & money by using a meter to measure how much water has run through the system, triggering a regeneration only when necessary. Meter Initiation can also extend the life of the system’s resin.

An atom, or group of atoms in a solution which function as a unit, and has a positive or negative electrical charge, due to the gain or loss of one or more electrons. It is smaller than a colloid.

Ion Exchange
A reversible process in which ions are released from an insoluble permanent material in exchange for other ions in a surrounding solution; the direction of the exchange depends upon the affinities of the ion exchanger for the ions present and the concentration of the ions in the solution. The ion exchanger media is an insoluble permanent solid medium.

The dissociation of molecules into simpler, electronically charged particles. It is related to the gaining or losing of electrons causing the atoms to become electronically charged.

Lime Scale
Hard water scale containing a high percentage of calcium carbonate. Insoluble scale is commonly formed when water containing calcium carbonate is heated. It also forms in cold water but precipitates at a higher pH.

A component which measures the volume of water which has run through a conditioning system, and is used to trigger regeneration.

Generally refers to impurities like Calcium and Iron in your main water supply. The resin particles contained in the mineral tank are sometimes referred to as “Mineral.”

Mineral Tank
The tank which contains the resin. This tank also typically has the control valve & timer mounted on top of it.

National Sanitation Foundation, now referred to as NSF International.

A process of diffusion of a solvent such as water through a semi-permeable membrane which will transmit the solvent but impede most dissolved substances. The normal flow of solvent is from the dilute solution to the concentrated solution. Osmosis causes the stronger solution to become more diluted and tends to equalize the opposing solutions.

Parts Per Billion (ppb)
A basis for reporting the results of water and wastewater analysis, indicating the number of parts by weight of a dissolved or suspended constituent, per billion parts by weight of water or other solvent. One part per billion is equal to one microgram per liter, the preferred unit.

Parts Per Million (ppm)
A common basis for reporting the results of water and wastewater analysis, indicating the number of parts by weight of water or other solvent. In dilute water solutions, one part per million is practically equal to one milligram per liter, which is the preferred unit. 17.l ppm equals one grain per US gallon. One ppm equals one pound per million pounds of water.

pH (potential of Hydrogen)
An expression of the acidity of a solution; the negative logarithm of the hydrogen ion concentration (pH 1 very acidic; pH 14, very basic; pH 7, neutral). e.g., pH 5 is 10 times the acidity of 6 and 100 times the acidity of 7. pH is a measure of intensity and not capacity. It is the logarithm of the reciprocal of the hydrogen ion concentration of a solution. The neutral point of 7 indicates the presence of equal concentrations of free hydrogen and free hydroxide ions.

Potable Water
Water which is considered safe and fit for human consumption, culinary and domestic purposes and meets the requirements of the health authority having jurisdiction.

The process of returning the sodium ions to the mineral after it has exchanged all its sodium ions for calcium and magnesium from hard water. This is accomplished by first back-washing the mineral bed to free it of all foreign matter, them passing salt brine through the mineral. The sodium ions attach themselves to the mineral, and the calcium and magnesium combine with the chloride from the brine to form calcium and magnesium chlorides, which are rinsed down the drain. All water softeners using the ion-exchange process are regenerated with these basic steps. In similar fashion cation and anion components of a demineralizer as well as manganese greensand are recharged with comparable sequences.

Synthetic organic ion exchange material, such as the high capacity cation exchange resin widely used in water softeners. Technical name- sulfonated co-polymer of styrene and divinyl benzene.

Reverse Osmosis
A process for the removal of dissolved ions from water, in which pressure is used to force the water through a semi-permeable membrane, which will transmit the water but reject most other suspended and dissolved materials. It is called reverse osmosis because mechanical pressure is used to force the water to flow in the direction that is the reverse of natural osmosis, namely from the dilute to the concentrated solution.

The abbreviation for “reverse osmosis.”

The common name for the specific chemical compound sodium chloride (NaCl), used in the regeneration of ion exchange water softeners. In chemistry, the term is applied to a class of chemical compounds which can be formed by the neutralization of an acid with a base.

Softened Water
Any water that is treated to reduce hardness minerals to 1.0 GPG (17.1 mg/L) or less, expressed as calcium carbonate.

Total Dissolved Solids
The weight of solids per unit volume of water which are in true solution, usually determined by the evaporation of a measured volume of filtered water, and determination of the residue weight. TDS is expressed as ppm per unit volume of water. An electrical conductivity test provides only an estimate of the TDS since non-conductive substances cannot be measured by electrical means.

The operation of an ion exchange unit in which solutions are passed in at the bottom and out at the top of the container.

Water Conditioning
Virtually any form of water treatment designed to improve the quality of water, by neutralization, inhibition or removal of undesirable substances.

Water Softening
The reduction or removal of calcium and magnesium ions which are the principle cause of hardness in water.

Source: Water Softeners and Filters