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Saline Water |
Water containing an
excessive amount of dissolved salts, usually over 5,000 mg/l. |
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Salt |
In chemistry, the term is
applied to a class of chemical compounds which can be formed by the
neutralization of an acid with a with a base; the common name for the
specific chemical compound sodium chloride used in the regeneration of ion
exchange water softeners. |
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Salt Splitting |
The process in which
neutral salts in water are converted to their corresponding acids or bases
by ion exchange resins containing strongly acidic or strongly basic
functional groups. |
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Sample |
The water that is analyzed
for the presence of EPA-regulated drinking water contaminants. Depending
on the regulation, EPA requires water systems and states to take samples
from source water, from water leaving the treatment facility, or from the
taps of selected consumers. |
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Sanitary Survey |
An on-site review of the
water sources, facilities, equipment, operation, and maintenance of a
public water systems for the purpose of evaluating the adequacy of the
facilities for producing and distributing safe drinking water. |
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Saponification |
The process in which a
fatty acid is neutralized with an alkali or base to form a soap. |
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Scale |
A deposit of mineral solids
on the interior surfaces of water lines and containers, often formed when
water containing the carbonates or bicarbonates of calcium and magnesium
is heated. |
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Secondary Drinking Water
Standards |
Non-enforceable federal
guidelines regarding cosmetic effects (such as tooth or skin
discoloration) or aesthetic effects (such as taste, odor, or color) of
drinking water. |
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Sedimentation |
The process in which solid
suspended particles settle out of water, usually when the water has little
or no movement. Also called "settling". |
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Semipermeable Membrane |
Typically a thin, organic
film which allows the passage of some ions or materials while preventing
the passage of others. Some membranes will only allow the passage of
cations. (See electrodialysis.) Some membranes reject most dissolved
substances, but allow the passage of water. (See reverse osmosis.) |
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Septic |
A condition existing during
the digestion of organic matter, such as in sewage, by anaerobic bacteria
in the absence of air. A common process for the treatment of household
sewage in septic tanks, and in municipal sewage treatment in specially
designed digester. |
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Sequestering Agent |
A chemical compound
sometimes fed into water to tie up undesirable ions, keep them in
solution, and eliminate or reduce the normal effects of the ions. For
example, polyphosphate can sequester hardness and prevent reactions with
soap. (See cheating agent.) |
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Sequestration |
A chemical reaction in
which certain ions are bound into a stable, water soluble compound, thus
preventing undesirable action by the ions. (See chelate.) |
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Service Run |
That portion of the
operating cycle of a water conditioning unit in which treated water is
being delivered, as opposed to the period when the unit is being
backwashed, recharged or regenerated. |
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Service Unit |
A term sometimes applied to
softeners or filters which are regenerated or backwashed at a central
point, then transported to the point of use for connection to the water
system. (See portable exchange.) |
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Shielded |
The separation of metallic
parts by an electrical nonconductor; insulated by other than an air gap. |
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Silica Gel Or Siliceous
Gel |
A synthetic hydrated sodium
aluminosilicate with ion exchange properties, once widely used in ion
exchange water softeners. (See zeolite, gel zeolite.) |
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Sludge |
The semi-fluid solid matter
collected at the bottom of a system tank or watercourse, as a result of
the sedimentation or settling of suspended solids or precipitates. |
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Slug |
An abnormally high
concentration of an undesirable substance which passes through a water
system, usually brief or intermittent in nature, and often related to an
upset of a system. For example, a slug of iron may occur during high flow
which disturbs and suspends previously deposited iron precipitates. |
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Soap |
One of a class of chemical
compounds which possesses cleansing properties; formed by the reaction of
a fatty acid with a base or alkali. Sodium and potassium soaps are soluble
and useful, but can be converted to insoluble calcium and magnesium soaps
(curd) by the presence of these hardness ions in water. |
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Soda Ash |
the common name for sodium
carbonate, Na2CO3, a chemical compound used as an alkalinity builder in
some soap and detergent formulations to neutralize acid water, and in the
lime-soda water treatment process. |
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Sodium |
An ion found in natural
water supplies, and introduced to water in the ion exchange water
softening process. Sodium compounds are highly soluble, and do not react
with soaps or detergents. |
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Sodium Chloride |
The chemical name for
common salt, widely used in the regeneration of ion exchange water
softeners. |
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Sodium Cycle |
the cation exchange process
in which sodium on the ion exchange resin is exchanged for hardness and
other ions in water. Sodium chloride is the common regenerant used in this
process. |
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Soft Water |
Any water which contains
less than 1.0 gpg (17.1 mg/l) of hardness minerals, expressed as calcium
carbonate. |
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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. |
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Sole Source Aquifer |
An aquifer that supplies 50
percent or more of the drinking water of an area. |
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Solute |
The substance which is
dissolved in and by a solvent. Dissolved solids, such as the minerals
found in water, are solutes. |
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Solution Feeder |
A device, such as a power
driven pump or an eductor system, designed to feed a solution of a water
treatment chemical into the water system, usually in proportion to flow.
(See chemical feeder.) |
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Solvent |
The liquid, such as water,
in which other materials (solutes) are dissolved. (See solute.) |
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Source Water |
Water in its natural state,
prior to any treatment for drinking. |
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Specific Conductance |
The measure of the
electrical conductance of water or a water solution at a specific
temperature, usually 25oC. (See resistance.) |
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Specific Gravity |
The ratio of the weight of
a specific volume of a substance compared to the weight of the same volume
of pure water at 4oC. |
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Specific Resistance |
The measure of the
electrical resistance of water or a water solution at a specific
temperature, usually 25oC. (See resistance.) |
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Sphericity |
A measure of the roundness
and wholeness of an ion exchange resin bead. |
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Spore |
In general, specialized
reproductive bodies or resting cells. In water bacterial
"spores" resist adverse conditions which would readily destroy
the parent organism. |
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Stability Index |
See Langelier's Index. |
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Standard Methods |
The abbreviation for the
name of the reference book "Standard Methods for the Examination of
Water and Wastewater", widely used in water and waste water testing
and analysis. |
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Static |
Fixed in position, resting,
or without motion, as opposed to dynamic or moving. |
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Static System |
A system or process in
which the reactants are not flowing or moving. (See dynamic system.) |
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Sterilization |
A process in which all
living organisms are destroyed. (See disinfection.) |
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Strong Base Load Factor Z |
Is the total exchangeable
anions. Thus it is the sum of total anions (which equals the Y factor)
plus silica, plus carbon dioxide (not carbonic acid formed). 35 gpg is
considered upper limit for DI applications. |
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Sulfate |
In the range of 30 gpg,
sulfate salts can cause laxative effects and medicinal taste. In high
concentration with high calcium hardness, a white insoluble compound is
formed that is difficult to remove. |
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Sulfate-Reducing
Bacteria |
A group of bacteria which
are capable of reducing sulfates in water to hydrogen sulfide gas, thus
producing obnoxious tastes and odors. These bacteria have no sanitary
significance, and are classed as nuisance organisms. |
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Sulfonic Acid |
A specific acidic group
(SO3H) which gives certain cation exchange resins their ion exchange
capability. |
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Sulfur |
A yellowish solid element.
The term is also commonly used to refer to water containing hydrogen
sulfide gas. |
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Superchlorination |
The addition of excess
amounts of chlorine to a water supply to speed chemical reactions or
insure disinfection with short contact time. The chlorine residual
following superchlorination is high enough to be unpalatable, and thus
dechlorination is commonly employed before the water is used. |
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Supernatant |
The clear liquid lying
above a sediment or precipitate. |
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Surface Tension |
The result of attraction
between molecules of a liquid which causes the surface of the liquid to
act as a thin elastic film under tension. Surface tension causes water to
form spherical drops, and to reduce penetration into fabrics. Soaps,
detergents and wetting agents reduce surface tension and increase
penetration by water. |
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Surface Water |
The water that systems pump
and treat from sources open to the atmosphere, such as rivers, lakes, and
reservoirs. |
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Surface-Active Agent |
The material in a soap or
detergent formulation which promotes the penetration of the fabric by
water, the loosening of the soil from surfaces, and the suspension of many
soils; the actual cleaning agent in soap and detergent formulations. |
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Surfactant |
A contraction of the term
"surface-active agent". |
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Suspended Solids |
Solid particles in water
which are not in solution. |
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Swelling |
In the water treatment
context, the expansion of certain ion exchange resins when converted into
specific ionic states. |
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Syndet |
A contraction of the term
"synthetic detergent". |
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Synthetic Detergent |
A synthetic cleaning agent,
such as linear alkyl sulfonate and alkyl benzene sulfonate. Synthetic
detergents react with water hardness, but the products are soluble. |
