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ACID- A
substance which releases hydrogen ions
when dissolved in water.Most acids will
dissolves the common metals, and will
react with a base to form a neutral salt
and water.
ACTIVATED CARBON- A granular material
usually produced by the roasting of
cellulose base substances, such as wood
or coconut shells, in the absence of
air.It has a very porous structure and
is used in water conditioning as an
absorbent for organic matter and certain
dissolved gases. sometimes called "
activated charcoal ".
ABSORBENT- The process in which matter
adheres to the surface of an absorbant.
ALKALINITY- The quantitative capacity of
a water or water solution to neutralize
an acid. It is usually measured by
titration with a standard acid solution
of sulfuric acid, and expressed in terms
of its calcium carbonate equivalent.
ANION- a negatively charged ion in
solution, such as bicarbonate,chloride
or sulfate.
ANION EXCHANGE- An ion exchange process
in which anions in solution are
exchanged for other anions for an ion
exchanger. In demineralization, for
example, bicarbonate, chloride and
sulfate anions are removed from solution
in exchange for a chemically equivalent
number hydroxide anions from the anion
exchange resin.
AQUIFER- A layer or zone below the
surface of the earth which is capable of
yielding a significant volume of water.
ATOM- The smallest particle of an
element that can exist either alone or
in combination with similar
particles of the same element or of a
different element.
ATTRITION- The process in which solids
are worn down or ground down by
friction, often between particles of the
same material. filter media and ion
exchange materials are subject to
attrition during
backwashing , regeneration and service.
BACKWASH- The
process in which beds of filter or ion
exchange media are subjected to flow
opposite to the service flow direction
to loosen the bed and to flush suspended
matter, collected during the service
run, to waste.
BACTERIA- Unicellular micro-organisms
which typically reproduce by cell
division. Although usually classed as
plants, bacteria contain no chlorophyll.
BASE- A substance which releases
hydroxyl ions when dissolved in water.
Bases react with acids to form a neutral
salt and water.
BED- the ion exchange or filter media in
a column or other tank or operational
vessel.
BED DEPTH- the height of the ion
exchange or filter media in the vessel
after preparation for service
BICARBONATE ALKALINITY- the alkalinity
of a water due to the presence of
bicarbonate ions.
BIOCHEMICAL OXYGEN DEMAND- the amount of
oxygen consumed in the oxidation of
organic matter by biological action
under specific standard test conditions.
Widely used as a measure of the strength
of sewage and waste water.
BRINE- a strong solution of salts, such
as the sodium chloride 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.
CALCIUM- one of
the principal elements making up the
earths crust, the compounds of which
make the water hard. The presence of
calcium in water is a factor
contributing to the formation of scale
and insoluble soap curds which are a
means of clearly identifying hard water.
CAPACITY- an expression of the quantity
of an undesirable material which can be
removed by a water conditioner between
servicing of the media, i.e., cleaning
regeneration or replacement, as
determined under standard test
conditions. For ion exchange water
softeners, the capacity is expressed in
grains of hardness removal between
successive regenerations and is related
to the pound of salt used in
regeneration. For filters, the capacity
may be expressed in the length of time
or total gallons delivered between
servicing.
CARBONATE- the Co3- ion.
CARBONATE ALKALINITY- alkalinity due to
the presence of the carbonate ion.
CARBONATE HARDNESS- hardness due to the
presence of calcium and magnesium
bicarbonates and carbonates in water;
the smaller of the total hardness and
the total alkalinity.
CARBON DIOXIDE- a gas present in the
atmosphere and formed by the decay of
organic matter;the gas in carbonated
beverages; in water it forms carbonic
acid.
CATION- an ion with a positive
electrical charge, such as calcium,
magnesium and sodium.
CATION EXCHANGE- process in which
cations in solution are exchanged for
other cations from an ion exchanger.
CAUSTIC- Any substance capable of
burning or destroying animal flesh or
tissue. The term is applied to strong
bases.
CAUSTIC SODA- the common name sodium
hydroxide.
CHELATING AGENT- a chemical compound
sometimes fed to water to tie up
undesirable metal ions, keep them in
solution, and eliminate or reduce the
normal effects of the ion.
CHEMICAL OXYGEN DEMAND- the amount of
matter, both organic and inorganic, in a
water or wastewater which can be
oxidized by boiling with a strong
oxidizing acid under standard test
conditions, and expressed as the
equivalent amount of oxygen; often used
as a measure of the strength of sewage
and wastewater; includes materials not
oxidized in the BOD test, and thus does
not correlate with BOD.
CHLORINE- a gas, widely used in the
disinfection of water and an oxidizing
agent for organic matter, iron, etc.
CHLORINE DEMAND- a measure of the amount
of chlorine which will be consumed by
organic matter and other oxidizable
substances in a water before a chlorine
residual will be found; the difference
between the total chlorine fed and the
chlorine residual.
COAGULANT- a material, such as alum,
which will form a gelatinous precipitate
in water, and cause the agglomeration of
finely divided particles into larger
particles which can then be removed by
settling and/or filtration.
COAGULANT AID- a material which is not a
coagulant , but which improves the
effectiveness of a coagulant, often by
forming a larger or heavier particles,
speeding the reactions, or by permitting
reduced coagulant dosage.
COAGULATION- The process in which very
small, finely divided solid particles,
often colloidal in nature, are
agglomerated into larger particles.
COLLOID- very finely divided solid
particles which will not settle out of a
solution; intermediate between a true
dissolved particle and a suspended solid
which will settle out of solution. the
removal colloidal particles usually
requires coagulation to form larger
particles which may be removed by
sedimentation and/or filtration.
COMPENSATED HARDNESS- a calculated value
based on the total hardness, the
magnesium to calcium ratio and the
sodium concentration of a water. it is
used to correct for the reductions in
hardness removal capacity caused by
these factors in cation exchange water
softeners. No single method of
calculation has been widely accepted.
CONDUCTANCE- a measure of the ability of
a solution to carry electricity, the
reciprocal of the electrical resistance.
The unit of conductance is the
mho(reciprocal ohm).
CONDUCTIVITY- the quality or power to
carry electrical current; in water, the
conductivity is related to the
concentration of ions capable of
carrying electrical current.
CORROSION- the destructive
disintegration of a metal by
electrochemical means.
CYCLE- a series of events or steps which
ultimately lead back to the starting
point, such as the
exhaustion-regeneration cycle of an ion
exchange system; sometimes incorrectly
used in reference to a single step to a
complete cycle.
DEIONIZATION- the removal of all
ionized minerals and salts (both organic
and inorganic) from a solution by a two
stage ion exchange procedure. First,
positively charged for a chemically
equivalent amount of hydrogen ions.
Second, negatively charged ions are
removed by an ion exchange resin for a
chemically equivalent amount of
hydroxide ions. The hydrogen and
hydroxide ions are introduced in this
process unite to form water molecules.
The term is often used interchangeably
with demineralization.
DEMINERALIZATION- the removal of ionized
inorganic minerals and salts (not organic
materials)from a solution by a two phase
ion exchange procedure, similar to
deionization, and the two terms are
often used interchangeably.
D.I.- abbreviation for "deionization"
DIALYSIS- the separation of components
of a solution by diffusion through a
semi-permeable membrane which is capable
of passing certain ions or molecules
while rejecting others.
DIFFERENTIAL PRESSURE- the difference in
pressure at two points in a water
system, may be due to differences in
elevation or to friction losses or
pressure drops due to resistance to flow
in pipes, softeners, filters or other
devices.
DISINFECTION- a process in which
pathogenic (disease producing bacteria)
are killed; may involve disinfecting
agents such as chlorine, or physical
processes such as heating.
DISSOLVED SOLIDS- the weight of matter
in true solution in a stated volume of
water; includes both inorganic and
organic matter; usually determined by
weighing the residue after evaporation
of the water at 105 or180c.
DISTILLATION- the process in which a
liquid, such as water, is converted into
its vapor state and collected; used to
remove solids and other impurities from
water; multiple distillations are
required for extreme purity.
EFFICIENCY- the
ratio of output per unit input; the
effectiveness of performance of a
system; in an ion exchange system, often
expressed as the amount of regenerant
required to produce a unit of capacity,
such as the pounds of salt per kilogram
of hardness removal.
ELECTRODIALYSIS- a process in which a
direct current is applied to a cell to
draw charged ions through ion selective
semipermiable membranes, thus removing
the ions from the solution.
ENDPOINT- the point at which a process
is stopped because a predetermined value
of a measurable variable is reached, the
endpoint of an ion exchanger water
softener service run is the point at
which the hardness of the softener
effluent increases to a predefined
concentration, often 1.0 grain per
gallon; the endpoint of a filter service
run may be the point at which the
pressure drop across the filter reaches
a predetermined value; the endpoint of a
titration is the point at which the
titrant produces a predetermined color
change, ph value, or other measurable
characteristic.
EQUIVALENT PER MILLION- a unit of
concentration used in chemical
calculations, calculated by dividing the
concentration in ppm or mg/1 by the
equivalent weight.
EXHAUSTION- the state of an ion exchange
material in which it is no longer
capable of effective function due to the
depletion of the initial supply of
exchangeable ions; the exhaustion point
may be defined in terms of a limiting
concentration of matter in the effluent,
or in the case of demineralization, in
terms of electrical conductivity.
FILTER-
specifically, a device or system for the
removal of solid particles(suspended
solids); in general, includes mechanical,
adsorptive, oxidizing, and neutralizing
filters.
FIXTURE UNIT- an arbitrary unit assigned
to different types of plumbing fixtures,
and used to estimate flow rate
requirements and drain capacity
requirements.
FLOCCULATION- the agglomeration of
finely divided suspended solids into
larger, usually gelatinous, particles;
the development of a "floc" after
treatment with a coagulant by gentle
stirring or mixing.
FLOW CONTROL- a device designed to limit
the flow of water of regenerant to a
predetermined value over a broad range
of inlet water pressures.
FLOW RATE- the quantity of water a
regenerant which passes a given point in
a specified unit of time, often
expressed in gallons per minute.
FLUORIDATION- the addition of a fluoride
compound to a water supply to produce
the concentration desired for the
reduction in incidence of dental
carries.
FLUSH TANK- a tank or chamber in which
water is stored for pid release to flush
a toilet or water closet.
FLUSH VALVE- a self closing valve
designed to release a large volume of
water when tripped.
FOULING- the process in which
undesirable foreign matter accumulates
in a bed of filter media or ion
exchanger, clogging pores and coating
surfaces and thus inhibiting or
retarding the proper operation of the
bed.
FREE AVAILABLE CHLORINE- the
concentration of residual chlorine
present as dissolved gas, htpochlorous
acid or hypochlorite, not combined with
ammonia or in other less available form.
FREEBOARD- the vertical distance between
a bed of filter media or ion exchange
material and the overflow or collector
for backwash water; the height above the
bed of granular media available for bed
expansion during backwashing; may be
expressed either as a linear distance or
a percentage of bed depth.
GPG- abbreviation for
'grain per gallon'.
GRAIN- (gr.) a unit of weight equal to
1/7000th of a pound, or 0.0648 gram.
GRAIN PER GALLON- (gpg) a common basis
for reporting water analyses in the U.S.
and Canadaone grain per U.S. gallons
equals 17.12 milligrams per liter or
parts per million. one grain per British
gallon equals 14.3 milligrams per liter
or parts per million.
GRAM (g) the basic unit of weight
(mass) of the metric system, originally
intended to be the weight of 1 cubic
centimeter of water .
GREENSAND a natural mineral, primarily
composed of complex silicates, which
possess ion exchange properties.
HARDNESS 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.
HARDNESS LEAKAGE the presence of a
consistent concentration of hardness in
the effluent from an ion exchange water
softener, often due to high
concentrations of hardness or sodium in
the water being treated.
HARD WATER water with a total hardness
of one grain per gallon or more, as
calcium carbonate equivalent.
HEAD a measure of the pressure at a
point in a water system, expressed in
pounds per square, or in the height of a
column of water which could produce the
pressure.
HEAD LOSS see pressure drop.
HYDRAULIC referring to water or other
fluids in motion.
HYDRAULIC CLASSIFICATION a process in
which particles pf the same specific
gravity may be graded according to size
by backwashing or other relative upward
flow of water, with the smallest
particles tending to rise to the top of
the bed, and the largest particles
tending to sink to the bottom, because of
variations in weight to surface area
ratios.
HYDROGEN CYCLE the cation exchange cycle
in which the cation exchanger is
regenerated with acid, and cations are
removed from the solution treated, in
exchange for hydrogen ions.
HYDROGEN ION CONCENTRATION the
concentration of hydrogen ions in moles
per liter of solution; often expressed
as ph.
HYDROLOGIC CYCLE the water cycle,
including precipitation of water from
the atmosphere as rain or snow, flow of
water over or through the earth, and
evaporation or transpiration to water
vapor in the atmosphere.
HYDROLYSIS the reaction of a salt with
water to form an acid and a base.
HYDROXIDE a chemical compound of an
element or elements with the hydroxyl
(oh) anion.
HYPOCHLORITE the "OCI" anion,;
calcium
and sodium are commonly used as
disinfecting agents
ION an atom, or group
of atoms which function as a unit, and
has a positive or negative electrical
charge, due to the gain or loss of of
one or more electrons.
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 depends on the affinities of the
ion exchanger for the ions present, and
the concentrations of the ions in the
solution.
ION EXCHANGER a permanent, insoluble
material which contains ions that will
exchange reversibly with other ions in a
surrounding solution. Both cation and
anion exchangers are used in water
conditioning.
IONIZATION the process in which atoms
gain or lose electrons and thus become
ions with positive or negative charges;
sometimes used as synonymous with
dissociation, the separation of
molecules into charged ions in solution.
IONIZATION CONTANT a constant specific
for each partially ionizable chemical
compound to express the ratio of the
concentration of ions from the compound
to the concentration of un-ionized
compound.
IRON an element often found dissolved in
ground water in concentrations usually
ranging from zero to 10 ppm. It is
objectionable in water supplies because
of the staining caused after oxidation
and precipitation, because of taste, and
because of unsightly colors produced
when iron reacts with tannins in
beverages such as coffee and tea.
IRON BACTERIA organisms which are
capable of utilizing ferrous iron,
either from the water or from steel
pipe, in their metabolism, and
precipitating ferric hydroxide in their
sheaths and gelatinuos deposits. These
organisms tend to collect in pipe lines
and tanks during periods of low flow,
and to break loose in slugs in turbid
water to create staining, taste and odor
problems.
JACKSON TURBIDITY
UNIT an arbitrary unit of turbidity
originally based on a suspension of a
specific type of silica with the
turbidity measured in a Jackson Candle
Turbimeter.
KILO a prefix used to
indicate 1000 of the succeeding
unit. (abbreviation for kilogram).
KILOGRAIN one thousand grains
KILOGRAM one thousand grams
LANELIER'S INDEX
a calculated number used to predict
whether or not a water will
precipitate, be in equilibrium with, or
dissolved calcium carbonate. It is
sometimes erroneously assumed that any
water which tend to dissolves calcium
carbonate is automatically corrosive.
LIME the common name for calcium oxide.
LIME SCALE hard water scale containing a
high percentage of calcium carbonate.
LIMESTONE a sedimentary rock, largely
calcium carbonate, usually also
containing significant amounts of
magnesium carbonate.
LITER the basic metric unit of volume;
3,785 liters equals 1 U.S. gallon; 1
liter of water weighs 1000 grams.
MAGNESIUM one of
the elements making up the earths crust,
the compounds of which when dis-solved
in water make the water hard. The
presence of magnesium in water is a
factor contributing to the formation of
scale and insoluble soap curds.
MAGANESE an element sometimes found
dissolved in ground water, usually with
dissolved iron but in lower
concentrations; causes black stains, and
other problems similar to iron.
MANGANESE GREENSAND greensand which has
been processed to incorporate in its
pores and on its surface the higher
oxides of manganese. The product has a
mild oxidizing power, and is often used
in the oxidization and precipitation of
iron, manganese and/or hydrogen sulfide,
and their removal from water.
MEDIA the selected materials in a filter
that form the barrier to the passage of
certain suspended solids or dissolved
molecules.
MEDIUM singular form of media.
mg/l---The abbreviation for milligrams
per liter.
MICRON a linear measure equal to one
millionth of a meter.
MICRON RATING the term applied to a
filter to indicate the particle size of
suspended solids that will be removed.
As used in industry standards, this is
an "absolute", not "nominal" rating.
MILLIGRAM PER LITER a unit concentration
of matter used in reporting the results
of water andwaste-water analyses. In
dilute water solutions, it is practially
equal to the part per million, but
varies from the ppm in concentrated
solutions such as brine. As most
analyses are performed on measured
volumes of water, the mg/l is a more
accurate expression of the
concentration, and is the preferred unit
of measure.
MILLIMICRON a unit of length equal to
one thousandth of a micron, often used
to express the wave-length of colors of
visible light in colormetric analytical
procedures. The symbol for the
millimicron is "mu".
MINERAL a term applied to inorganic
substances, such as rocks and similar
matter found in the earths strata,
Minerals normally have definite chemical
composition and crystal stucture. The
term also applied
to matter derived from minerals, such as
inorganic ions found in water.
MOLE the molecular weight of a chemical
compound expressed in grams.
MOLECULE the simplest combination of
atoms that will form a specific chemical
compound; the smallest particle of a
substance which will still retain the
essential composition and properties of
that substance, and which can be broken
down only into atoms and simpler
substances.
MOST PROBABLE NUMBER (MPN) the term used
to indicate the number or organisms
which, according to statistical theory,
would be most likely to produce the
results observed in certain
bacter-iological tests,; usually
expressed as a number of 100 ml of
water.
NEGATIVE
CHARGE the electrical charge on an
electrode or ion in solution, due to the
presence of an excess of electrons.
NEUTRAL in electrical systems, the term
used to indicate neither an excess or
lack of electrons; a condition of
balance between positive and negative
charges. In chemistry, the term used to
indicate a balance between acids and
bases; the neutral point on the ph scale
is 7.0 indicating the presence of equal
numbers of free hydrogen (acidic) and
hydroxide (basic) ions.
NONCARBONATE HARDNESS water hardness due
to the presence of compounds such as
calcium and magnesium chlorides,
sulfates or nitrates, the excess of
total hardness over total alkalinity.
OPERATING
PRESSURE the range of pressure,
usually expressed in pounds per square
inch, over which a water conditioning
device or water system is designed to
function.
OSMOSIS a process of diffusion of a
solvent such as water through a
semipermeable membrane which will
transmit the solvent but impede most
dissolved substances. The normal flow of
solvent is from the dilute solution to
the concentration solution.
OXIDATION a chemical process in which
electrons are removed from an atom, ion
or compound. The addition of oxygen is a
specific form of oxidation, while the
rusting of iron is a slow form.
PARTICLE SIZE
as used in industry standards, the size
of a particle suspended in water as
determined by its smallest dimension,
usually expressed in microns.
PARTS PER MILLION (ppm) a common basis
for reporting the results of water and
wastewater analyses, indicating the
number of parts by weight of a dissolved
or suspended constituent, per million
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.
PATHOGEN an organism which may cause
disease.
PERMANENT HARDNESS water hardness due to
the presence of the chlorides and
sulfates of calcium and magnesium, which
will not be precipitated by boiling.
this term is largely replaced by "noncarbonate
hardness".
PH the reciprocal of the logarithm of
the hydrogen ion concentration. The ph
scale is from zero to 14,and 7.0 is the
neutral point, indicating the presence
of equal concentrations of free hydrogen
and hydroxide ions, ph values below 7.0
indicate increasing acidity, and ph
values above 7.0 indicate in-
creasing base concentrations.
PORTABLE EXCHANGE a term applied to
water softeners and filters which are
designed for
connection to a water system with
special fittings and disconnection and
transport to a central station or plant
for regeneration or servicing.
POSITIVE CHARGE the electrical charge of
an electrode or ion in solution due to
the removal of electrons.
PPM the abbreviation for part per
million.
PRECIPITATE to cause a dissolved
substance to form a solid particle which
can be removed by settling or filtering,
such as the removal of dissolved iron by
oxidation, precipitation, and
filtration. The
term is also used to refer to the solid
formed, and to the condensation of water
in the atmosphere to form rain or snow.
PRESSURE DIFFERENTIAL the difference in
pressure between two points in a system
due to the differences in elevation
and/or pressure drop due to flow.
PRESSURE DROP a decrease in water
pressure during flow due to internal
friction between molecules of water, and
external friction due to irregularities
or toughness in surfaces past which the
water flows.
RATED CAPACITY the
basis for calculating the period of
time, or number of gallons delivered by
a water softener or filter, between
regenerations or servicing, as
determined under specific test
conditions.
RATED PRESSURE DROP the pressure drop of
water softener or filter at the rated
service flow, with clean water at a
temperature of 60degrees. with a freshly
regenerated and/or backwashed softener
or filter, as determined under standard
test conditions.
RATED SERVICE FLOW the manufacturer's
specified maximum flow rate at which a
water softener will deliver soft water,
or a filter will deliver quality water
as specified for its type, as determined
under
standard test conditions. A manufacturer
may also specify a minimum flow rate or
a range of service flows.
RATED SOFTENER CAPACITY a water softener
capacity rating based on grains of
hardness re-moved while producing soft
water between successive regenerations,
as determined under standard test
conditions.
RAW WATER untreated water, or any water
before it reaches a specific water
treatment device or process.
REDUCTION a chemical process in which
electrons are added to an atom, ion or
compound.
RED WATER water which has a reddish or
brownish appearance due to the presence
of precipitated iron and/or iron
bacteria.
REGENERANT a solution of a chemical
compound used to restore the capacity of
an ion exchange system. Sodium chloride
brine is used as a regenerant for ion
exchange water softeners, and acids and
bases are used as regenerants for the
cation and anion resins used in
demineralization.
REGENERATION in general, includes the
backwash, brine, and fresh water rinse
steps, necessary to prepare a water
softener exchange bed for service after
exhaustion. Specifically, the term may
be applied to the 'brine' step in which
the sodium chloride solution is passed
through the exchanger bed. The term may
also be used for similar operations
relating to the demineralizers and
certain filters.
REGENERATION LEVEL the quantity of
regenerant used in the regeneration of
an ion exchange unit , usually expressed
in pounds per regeneration and/or pounds
per regeneration per cubic foot of ion
exchange.
RESIDUAL the amount of a specific
material remaining in the water
following a water treatment process. May
refer to material remaining as a result
of incomplete removal or to material
meant to remain in the treated water.
RESIN synthetic organic ion exchange
material, such as the high capacity
exchange resin widely used in water
softeners.
REVERSE DEIONIZATION the use of the
anion exchange resin ahead of the cation
exchange resin in a deionization system.
REVERSE OSMOSIS a process for the
removal of dissolved ions from water, in
which pressure is used to force the
water through semipermeable membrane,
which will transmit the water but reject
most other dissolved materials.
SALINE WATER water
containing an excessive amount of
dissolved salts, usually over 10,000
mg/l.
SALT the common name for the specific
chemical sodium chloride, used in
regeneration of ion exchange water
softeners.
SEQUESTER a chemical reaction in which
certain ions are bound into a stable,
water soluble compound, thus preventing
undesirable action by the ions.
SEQUESTERING AGENT a chemical sometimes
fed into water to tie up undesirable
ions, and eliminate the normal effects of
the ions.
SOAP one of a class of compounds which
possesses cleaning properties, Sodium
and potassium are soluble and useful.
SODA ASH the common name for sodium
carbonate, chemical compound used as an
alkaline builder in some soap and
detergent formulations, to neutralize
acid water, and in the lime-soda ash
water treatment process.
SODIUM an ion found in natural water
supplies, and introduced to water in the
ion exchange water softening process.
SODIUM CHLORIDE the chemical name for
common salt, used in regeneration.
SOFT WATER any water which contains less
than 1.0 gpg(17.1 mg/l) of hardness
minerals, expressed as calcium
carbonate.
SOFTENED WATER any water that is treated
to reduce hardness minerals to 1.0 gpg
or less.
SOLUTE the substance which is dissolved
in a solvent. Dissolved solids, such as
the minerals found in water, are
solutes.
SOLVENT the liguid, such as water, in
which other materials (solutes) are
dissolved
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 4 degrees c.
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.
SULFUR a yellowish solid element. The
term is also used as a slang expression
to refer to water containing hydrogen
sulfide gas.
TDS the abbreviation
for "total dissolved solids"
THRESHOLD a very low concentration of a
substance in water. The term is
sometimes used to indicate the
concentration which can just be
detected.
TITRATION an analytical process in which
a standard solution in a calibrated
vessel is added to a measured volume of
sample until an end point, such as color
change, is reached. From the volume of
the sample and the volume of standard
solution used, the concentration of a
specific material may be calculated.
TOTAL ACIDITY the total of all forms of
acidity, including mineral acidity,
carbon dioxide and acid salts. Total
acidity is usually determined by
titration with a standard base solution
to the phenolphathlein endpoint.
TOTAL ALKALINITY the alkalinity of a
water as determined by titration with
standard with standard acid solution to
the methyl orange endpoint(ph approx.
4.5); sometimes abbreviated as "M
alkalinity" Total alkalinity includes
many components, such as hydroxides,
carbonates, and bicarbonates.
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 of the residue
weight.
TOTAL HARDNESS the sum of all hardness
constituents in a water, expressed as
their equivalent concentration of
calcium carbonate. Primarily due to the
calcium and magnesium in solution, but
may include small amounts of metals such
as iron which can act like calcium and
magnesium in certain reactions.
TOTAL SOLIDS the weight of all solids,
dissolved and suspended organic and
inorganic, per unit volume of water;
usually determined by the evaporation of
a measured volume of water at 105c in a
preweighed dish.
TURBIDITY a measure of the amount of
finely divided suspended matter in
water, which causes the scattering and
absorption of light rays.
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