Commonly Used Water Terms A - F
Welcome to the Water Guy list of commonly used water terms. Navigate the page
sections below:
ACID
A substance which releases hydrogen ions when dissolved in water. Most acids
will dissolve 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 adsorbent for organic
matter and certain dissolved gases. Sometimes called "activated charcoal."
ADSORBENT
A substance which has the capacity to adsorb.
ADSORPTION
The process in which matter adheres to the surface of an adsorbent.
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 from an ion exchanger. In demineralization, for example, bicarbonate.
chloride. and sulfate anions are removed from solution in exchange for a
chemically equivalent number of 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 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 classified 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 (HCO3-).
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 salt(s), such as the sodium chloride brine used in the
regeneration of ion exchange water softeners; also applied to the mixed sodium,
calcium, and magnesium chloride waste solution from regeneration.
CALCIUM
One of the principal elements making up the earth's crust; its compounds. when
dissolved, 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
Ion exchange process in which cations in solution are exchanged for other
cations from an ton exchanger.
CAUSTIC
Any substance capable of burning or destroying animal flesh or tissue. The term
is usually applied to strong bases.
CAUSTIC SODA
The common name for sodium hydroxide.
CHELATE
To form a complex chemical compound in which an ion, usually metallic, is bound
into a stable ring structure.
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 waste water
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 waste water; includes materials not
oxidized in the BOD test, and thus does not correlate with BOD.
CHLORINE
A gas, C12, 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 larger or heavier particles, speeding the reactions,
or 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 of 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 condw~tance 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 of a complete cycle.
DEIONIZATION
The removal of all ionized minerals and salts (both organic and inorganic) from
a solution by a two-phase ion exchange procedure. First, positively charged ions
are exchanged 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.
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. or DI
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 pressures 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 or 180?C.
DISTILLATION
The process in which a liquid, such as water, is converted into its vapor state
by heating, and the vapor cooled and condensed to the liquid 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.
ELECTRO DIALYSIS
A process in which a direct current is applied to a cell to draw charged ions
through ion-selective semi-permeable 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 exchange 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/l by the equivalent weight.
EXHAUSTION
The state of an ion exchange material in which it is no longer capable of
effective functioning 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 or regenerant to a predetermined
value over a broad range of inlet water pressures.
FLOW RATE
The quantity of water or 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 caries.
FLUSH TANK
A tank or chamber in which water is stored for rapid release to flush a toilet
or water closet.
FLUSH VALVE
A self-closing valve designed to release a large volume of water when tripped.
to flush a toilet or water closet.
FOULING
The process in which undesirable foreign matter accumulates in a bed of filter
media or ion exchanger. clogging pores and coating surfaces. thus inhibiting or
retarding the proper operation of the bed.
FREE AVAILABLE CHLORINE
The concentration of residual chlorine present as dissolved gas, hypochlorous
acid or hypochlorite, not combined with ammonia or in other less readily
available forms.
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.
|
