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Definitions:
A
absolute filter rating: Filter rating meaning that
99.9% (or essentially all) of the particles larger than a specific micron
rating will be trapped on or within the filter.
absorption: The process of one substance actually penetrating
into the structure of another substance. This is different from adsorption
in which one substance adheres to the surface of another.
accumulation tank: A vessel or tank, which receives
and stores product water for use on demand.
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. An acid is the opposite
of an alkali, has a pH rating lower than 7.0, will turn litmus paper
red and has a sour taste.
activated alumina: A medium made by treating aluminum
ore so that it becomes porous and highly adsorptive. Activated alumina
will remove several contaminants including fluoride, arsenic and selenium.
This medium requires periodic cleaning and appropriate reagent such
as alum, acid and or/caustic.
activated carbon: A water treatment medium, found
in block, granulated, or powder form, which is produced by heating carbonaceous
substances (bituminous coal or cellulose-based substance such as wood
or coconut shell) in the absence of air, creating a highly porous adsorbent
material.
adsorption: The physical process occurring when liquids,
gases or suspended matter adhere to the surface of, or in the pores
of, an adsorbent medium. Adsorption is a physical process which occurs
without chemical reaction.
aeration: The process whereby water is brought into
intimate contact with air by spraying or cascading, or air is brought
into intimate contact with water by an air aspirator or by bubbling
compressed air through the body of water. Both pressure (closed) aerators
and open (gravity) aerators are used. Closed aeration is used chiefly
for oxidation; open aeration for degassing.
aerobic: An action or process conducted in the presence
of air, such as aerobic digestion of organic matter by bacteria.
aesthetic contaminants: Characteristics of water which
affects its taste, odor, color and appearance (and may affect the objects
touched by the water) but which do not in themselves have any adverse
health effects in otherwise potable water.
algae: Single-celled or simple multi-celled organisms,
commonly found in surface water, which produce their own food through
photosynthesis. Excessive algae growth may cause the water to have undesirable
odors or tastes and decay of algae can deplete the oxygen in the water.
alkali: A substance which creates a bitter taste and
a slippery feel when dissolved in water and will turn litmus paper blue.
An alkali has a pH greater than 7.0 and is the opposite of an acid.
Highly alkaline waters tend to cause drying of the skin.
amoeba: A single celled protozoan that is widely found
in fresh and salt water. Some types of amoebas cause diseases such as
amoebic dysentery.
anaerobic: A condition in which there is no air or
no available free oxygen.
anaerobic organisms: An organism that can strive in
the absence of oxygen (air), such as bacteria in a septic tank.
anion: An ion with a negative charge.
aqueous: Containing water; watery.
aquifer: A natural water-bearing formation which is
found below the surface of the earth.
back pressure: Pressure which creates resistance against
a flow of water.
backflow: The flow of water in a pipe or line in a
direction opposite to the normal flow.
bacteria: Single-celled organisms (single form = bacterium)
which lack well-defined nuclear membranes and other specialized functional
cell parts and reproduce by cell division or spores. Bacteria may be
free-living organisms or parasites. Bacteria (along with fungi) are
decomposers that break down the wastes and bodies of dead organisms
making their components available for reuse. Bacteria cells range from
about 1 - 10 micron in length and from .2 - 1.0 micron in width. They
exist almost everywhere on earth. Despite their small size, the total
weight of all bacteria in the world likely exceeds that of all other
organisms combined. Some bacteria are helpful others are harmful.
bactericide: Any substance or agent which kills bacteria.
bacteriostatic: Having the ability to inhibit the
growth of bacteria without destroying the bacteria. For example: silver-impregnated
activated carbon will reduce bacterial colonization but not eliminate
it.
ballast: The power supply to activate and regulate
voltage in an ultraviolet (UV) lamp.
beaver fever: See Giardia lamblia.
biocide: A chemical which can kill or inhibit the
growth of living organisms such as bacteria, fungi, molds and slimes.
Biocides can be harmful to humans.
biodegradables: Subject to degradation (break down)
into simple substances by biological action. For example: the breakdown
of detergents, sewage wastes and other organic matter by bacteria.
bleach: A strong oxidizing agent and disinfectant
formulated to break down organic matter and destroy biological organisms.
blinding: The reduction or shutting off of flow due
to filter medium or membrane fouling.
brackish water: Water containing dissolved solids
in the range > 1,000 to < 15,000 ppm .
breakthrough: The appearance in the product water
of an amount of the contaminant which exceeds the design performance
criteria.
brine: A strong solution of salt(s) with total dissolved
solid s concentrations. The waste solution in both automatic water softeners
and reverse osmosis systems.
calcium (CA): One of the principal elements making
up the earth's crust. Calcium compounds, when dissolved, make hard water.
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.
capillary action: A phenomenon in which water or other
liquids will rise above the normal liquid level in a tiny tube or capillary
due to the attraction of the molecules in the liquid for each other
and for the walls of the tube.
carbon ( C ): An element which is found in almost
all living or formerly living matter including plants, proteins, organics
and hydrocarbons. Carbon combines readily with oxygen to form carbon
dioxide (CO2 ). The term "carbon" is sometimes used as a short
reference for activated carbon.
carbonaceous: Containing carbon and derived from organic
substances such as coal, coconut shells and wood.
carcinogens: A substance that can cause cancer.
cartridge: Any removable pre-formed or pre-packaged
component containing a filtering medium, ion exchanger, membrane or
other treatment material which fits inside a housing to make up a cartridge
filter.
cartridge filter: A device often used for single faucet
water treatment, made up of a housing and a removable cartridge (element).
In residential filtering systems, disposable elements are used.
catalysis: The speeding up (usually) of a chemical
reaction by adding a specific substance, the catalyst. Although the
catalyst causes the speedup of the reaction, it (the catalyst) is not
changed chemically in any way.
cation: An ion carrying one or more positive charges.
caustic: Any substance capable of burning or destroying
flesh or tissue. The term usually applies to strong bases.
cellulose acetate (CA) and cellulose triacetate (CTA):
A cellulose ester obtained by introducing the acetyl radical (CH3CO-)
of acetic acid into cellulose (as cotton or wood fibers) to produce
a tough plastic material which is used to make the cellulosic type of
semipermeable reverse osmosis membranes.
centrigrade also known as celsius: A temperature scale
in which 100 degrees is the boiling point and zero degrees the freezing
point for water at sea level.
channeling: The flow of water through a limited number
of passages in a filter.
charcoal: An adsorbent carbon product which has about
one-third the surface area of activated carbon.
check valve: A valve which will allow water to pass
in one direction but will close and prevent flow (backflow) in the opposite
direction.
chloramines: Chemical complexes formed from the reaction
between ammonia and chlorine being used to disinfect many municipal
water supplies. Unlike chlorine, chloramines do not combine with organics
in the water to form potentially dangerous trihalomethanes (THMs). Water
containing chloramines may not be used for fish or for kidney dialysis
applications.
chlorine (Cl2): A gas widely used in the disinfection
of water and as an oxidizing agent for organic matter . Chlorine is
known to react with organic matter in the water to form trihalomethanes
(THMs), a suspected carcinogen.
clear water iron: See ferrous iron.
Coliform bacteria: A particular group of bacteria
primarily found in human and animal intestines and wastes. These bacteria
are widely used as indicators organisms to show the presence of such
wastes in water and the possible presence of pathogenic (disease producing)
bacteria. Escherichia coli (E. coli) is one of the fecal coliform bacteria
widely used for this purpose.
color: A shade or tint which is imparted to water
by substances which are in true solution and thus cannot be removed
by mechanical filtration. Color is most commonly caused by dissolved
organic matter, but it may be produced by dissolved mineral matter.
contact time: The time the water is allowed to contain
the disinfectant to assure potability. Contact time may also be called
retention time.
contaminant: Any undesirable physical, chemical or
microbiological substance or matter in a given water source or supply.
Anything in water which is not H2O may be considered a contaminant.
cross contamination: The intermixing of two water
streams which results in unacceptable water quality for a given purpose.
cryptosporidium: A waterborne protozoan that forms
cysts and causes acute gastrointestinal illness in humans, Cryptosporidium
is commonly found in unfiltered surface water and is resistant to disinfectants
such as chlorine and ultraviolet light, but it can be removed by filters
that capture all particles of one micron and greater in size.
cyst: A capsule or protective sac produced about themselves
by many protozoans (as well as some bacteria and algae) as preparation
for entering a resting or a specialized reproductive stage. Similar
to spores, cysts tend to be more resistant to destruction by disinfectant.
Fortunately, protozoan cysts are typically 2-50 microns in diameter
and can be removed from water by fine filtration.
depth filtration: A filtration process in which water
flows through progressively smaller pore spaces in a filter. Depth filters
are designed to entrap particles throughout the mass of the filter media,
as opposed to a surface filter where only the surface layer does the
actual filtering.
desalination: The removal of dissolved inorganic solids
(salts) from solution such as water to produce a liquid which is free
of dissolved salts. Desalination is typically accomplished by distillation,
reverse osmosis or electrodialysis.
dew point: The temperature to which air must be cooled
to cause condensation of the water vapor it contains.
disinfection: The treatment of water to inactivate,
destroy and /or remove pathogenic (disease producing) bacteria, viruses,
cysts, and other microorganisms for the purpose of making the water
microbiologically safe for human consumption. Disinfection may involve
the use of disinfecting chemicals such as chlorine, iodine, ozone or
peroxide; or it may involve physical processes such as distillation,
microfiltration, ultrafiltration, boiling or ultraviolet radiation.
Disinfection may also be called sterilization.
dissolved solids also known as total dissolved solids:
The weight of matter, including both organic and inorganic matter, in
true solution in a stated volume of water. The amount of dissolved solids
is usually determined by filtering water through a 0.45 pore-diameter
micron filter and weighing the filtration residue left after the evaporation
of the water at 180 degree C.
distillate: The product water, which is mineral-free
and potable, from a distiller unit.
distillation: The process of separating the water
from the organic and inorganic contaminants through a combination of
evaporation (or vaporization), cooling and condensation.
distilled water: Water which has been cleansed by
passing through one or more evaporation-condensation cycles until it
contains a very low amount of dissolved solids (usually less than 5.0
ppm TDS).
drain: A pipe or conduit which carries liquids by
gravity to waste.
drain line: A pipe line which is used to carry water
from the water treatment system to a waste system.
drinking water: A water treated or untreated which
is intended for human use and consumption and considered to be free
of harmful chemicals and disease-causing bacteria, cysts, viruses or
other microorganisms. See also potable water.
efficiency (media filtration): The percent of contaminant
reduction which occurs with a specified medium volume and specified
water contact time.
efficiency (membrane filtration): The figure obtained
(expressed as a percent) by dividing the volume gallons pf product water
produced by the total volume (gallons) of feed water fed to the particular
unit or system.
effluent: The outflow from any water processing system
or device. Sometimes used to mean the product water of a given device
or system.
ejection: The process of forcing something out, expelling
it.
enzyme: A chemical produced by living cells, which
can bring about the digestion (breakdown) of organic molecules into
smaller units that can be used by living cell tissues.
Escherichia coli (E coli): One of the members of the
coliform bacteria group normally found in human and animal intestines
and indicative of fecal contamination when found in water. Determination
of whether E. coli is present is often used to measure the microbiological
safety of drinking water supplies.
evaporation: The process by which a substance is changed
from the liquid to the vapor state.
evaporation chamber: The part of a distillation system
in which water is changed into vapor.
evaporite: A mineral precipitated
as a result of evaporation, such as the solids left behind in the distillation
process.
facultative organisms: Microbes capable of adapting
to either aerobic or anaerobic environments.
fahrenheit: A temperature scale in which water freezes
at 32 degrees and boils at 212 degrees at atmospheric pressure.
fecal matter: Matter (feces) containing or derived
from animal or human bodily wastes that are discharged through the anus.
fecal coliform: Coliform bacteria found in fecal
matter.
feed pressure: The pressure at which water is supplied
to a water treatment device.
feedwater: The water to be treated that is fed into
a given water treatment system.
fermentation: The conversion/breakdown of organic
matter by anaerobic bacteria into carbon dioxide, methane and similar
compounds of low molecular weight.
ferric iron: Small solid iron particles containing
trivalent iron, which are suspended in water and visible as "rusty
water". Ferric iron can normally be removed by filtration. Also
known as precipitated iron.
ferrous iron: A divalent iron ion, usually as ferrous
bicarbonate which when dissolved in water produces a clear solution.
It is usually removed by cation exchange water softening. Also called
clear water iron.
filter: A device installed as part of the water system
through which water flows for the purpose of removing turbidity, taste,
color, iron or odor.
filter media: The selected materials in a filter that
form the barrier to the passage of filterable suspended solids or dissolved
molecules. Filter media are used to remove undesirable materials, tastes
and odors from a water supply.
filtrate: The effluent liquid from a filter system;
that part of the feed stream which has passed through the filter.
filtration: The process of separating solids from
a liquid by means of a porous substance such as permeable fabric or
membrane or layers of inert media.
fines: Extremely small particles which are smaller
than the specified size (in millimeters) for the medium.
flow controller: An in-line device or orfice fitting
which regulate and control flow of water.
flow rate: The quantity of water which=h passes a
given point in a specified unit of time, offen expressed in U.S. gpm
(or L/min).
fluoridation: The addition of fluoride compound to
a potable water supply to produce the concentration desired (about one
PPM) for the purpose of the reduction of dental caries (tooth decay).
fluoride: A natural occurring constituent of some
water supplies, an excess of which (over 2.0ppm) can cause discolored
teeth.
fouling: (filtration): The accumulation of undesirable
foreign matter in a filter causing clogging of pours coating of surfaces
and inhibiting or limiting the proper operation of the treatment system.
fouling (reverse osmosis): A phenomenon in which a
reverse osmosis membrane adsorbs, interacts with or becomes coated by
solutes and or precipitates in the feed stream resulting in a decrease
in membrane performance by lowering the flux and /or affecting the rejection
solutes.
free available chlorine (FAC): The concentration of
residual chlorine present as dissolved gas, hypochlorous acid or hypochlorite
ion but not including that chlorine combined with ammonia or other less
readily available forms of chlorine.
fresh water: water having less than approximately
1,000 mg/L (ppm) of total dissolved solids (TDS).
fungi: (singular = fungus) Plantlike organisms with
cells that have distinct nuclei surrounded by nuclear membranes as well
as other specialized functional cell parts but that cannot carry photosynthesis.
Most fungi are decomposers of wastes and dead bodies from other organisms;
a few are parasites. Yeasts, molds, mildew and mushrooms are all fungi.
Gallinea ferruginea: One of several types of bacteria
that use iron in their metabolism and are capable of depositing gelatinous
ferric hydroxide. Also known as iron bacteria.
germicidal ultraviolet: An ultraviolet light that
peaks at a 2,537 angstrom wavelength and is in a wavelength that lies
between 200 and 300 nanometers. This is known as the germicidal or short-wave
ultraviolet band.
giardia: A common waterborne protozoan that forms
cysts and is resistant to disinfectants such as chlorine and ultraviolet
light. Giardia can be removed by filters that all particles of four
microns and greater in size.
Giardia lamblia: A type of cyst found in the intestines
of mammals and in water contaminated by mammal droppings. The giardia
lamblia cyst, which is common and is frequently carried by water, is
capable of causing a contagious waterborne disease characterized by
acute diarrhea. This disease is referred to as beaver fever, because
beaver droppings can contain giardia lamblia.
groundwater: Water found beneath the surface of the
ground. Ground water is primarily water which has seeped down from the
surface by migrating through the interstitial spaces in soils and geologic
formations.
H20: The chemical formula for water (dihydrogen oxide).
half -life: The time required for half of the substance
present at the beginning to dissipate or disintegrate.
halogens: A family group pf elements including bromine,
chlorine, fluorine, astatine and iodine.
hardness: A common quality of water which contains
dissolved compounds of calcium and magnesium and sometimes other divalent
and trivalent metallic elements.
health contaminant: Any substance or condition that
may have any adverse effect on human health.
heterotrophic plant count (HPC): A procedure for estimating
the total number of live non photosynthetic bacteria in water. Colony
forming units (CFU) are counted after spreading the sample over a membrane
or spread plate and incubating in an amiable growth medium (agar) and
at an amiable temperature. These are generally not considered disease-causing
bacteria.
hexametaphosphate: A chemical such as sodium hexametaphosphate,
added to water to increase the solubility of certain ions and to deter
precipitation of certain chemicals.
hydrostatic test: A pressure test procedure in which
a vessel or system is filled with water, purged of air, sealed , subjected
to water pressure and then observed and/or tested for leaks, distortion
and/or mechanical failure.
influent: The stream of water to be treated as it
flows into any kind of water treatment unit or device, such as hard
water into a water softener or turbid water into a filter.
inorganic matter: Chemical substances which do arise
from the process of living growth, are composed of matter other than
plant or animal matter. And don't contain hydrocarbons of compounds
basically carbon structure. Examples are minerals and metals.
installation: The connecting or setting up and start
up operation of any water treatment system.
iodine (I): A nonmetallic element which is the heaviest
and least reactive of the naturally occurring halogens. It may be use
for disinfection. In both its liquid and vapor forms, iodine is readily
adsorbed by activated carbon.
ion exchange: A reversible chemical process in which
ions from an insoluble permanent solid medium (the "ion exchanger"
usually resin) are exchanged for ions in a solution or fluid mixture
surrounding the insoluble medium.
iron (Fe): A very common element often present in
groundwater in amounts ranging from 0.01 to 10.0 ppm (mg/L) Iron can
be found in three forms
1. Soluble form as in ferrous bicarbonate.
2. Bound with a soluble organic compound
3. As suspended ferric iron particles
iron bacteria: Bacteria which thrives on iron and
are able to actually use ferrous iron (as found in water or steel pipes)
in their metabolic processes, to incorporate ferric iron in their cell
structure, and to deposit gelatinous ferric hydroxide iron compounds
in their life processes.
iron fouling: The accumulation of iron on or within
an ion exchange resin bed or filter medium in such amounts that the
capacity of the medium is reduced.
jackson turbidity unit (JTU): A formerly used measurement
of the turbidity in a water sample. This has been replaced by the nephelometric
turbidity unit (NTU).
kinetics: the study of the relationships between temperature
and the motion and velocity of very small particles. Kinetic relationships
influence the rate of change in a chemical or physical system.
leach: To dissolve out by the action of a percolating
liquid.
leach field: The area where the effluent from a septic
tank system is distributed by horizontal underground piping designed
to aid in the process of natural leaching and percolation through the
soil.
Legionella: Over 26 species of bacteria, such as Legionella
pneumophila, which can cause pneumonia-like illness called "Legioella
Disease" (after the American Legion convention at which the disease
first drew attention). These bacteria are known to thrive at 100 degrees
F and are believed to live in infected humidifiers, cooling tower water
and shower rooms. Infection is by inhalation.
lime (CaO): A calcined chemical material, calcium
oxide.
lime scale: Hard water scale formed in pipes and vessels
(generally more severe on the hot water side) containing a high percentage
of calcium carbonate (CaCO3) or magnesium carbonate MgCO3).
longitudinal flow: A flow pattern in which water travels
from the bottom to top (or vice versa) in either a cartridge or loose
media tank-type filtration system. The advantages are greater contact
time, higher unit capacity, more complete utilization of medium and
more uniform water quality. Also called axial flow.
loop: A plumbing connection used to bypass water around
a location designed for installation of a water treatment system or
used when the treatment system is out of service for any reason.
magnesium (Mg): one of the elements that make up the
earth's crust as part of many rock-forming minerals such as dolomite.
Magnesium and calcium dissolved in water constitutes hardness. The presence
of magnesium in water contributes to the formation of scale and insoluble
soap which identify hard water.
manganese (Mn): An element sometimes found dissolved
in groundwater usually in combination with - but in lower concentrations
than iron. Manganese is noticeable because in concentrations above 0.05mg/L
it causes black staining of laundry and plumbing fixtures.
mechanical filter: A pressure or gravity filter designed
to physically separate and remove suspended solids from a liquid by
mechanical (physical) means rather than by chemical means.
media: A selected group of material used in filters
and filter devices to form barriers to the passage of certain solids
or molecules which are suspended or dissolved in water.
membrane: A thin sheet or surface film, either natural
or man-made of microporous structure that performs as an effluent filter
of particles down to the size range of chemical molecules and ions.
Such membranes are termed "semipermeable" because some substances
will pass through but others will not.
mesh size: Mesh is the number of openings in a square
inch of a screen or sieve. It is equal to the square of the number of
strains of metal or plastic screening per lineal inch.
methane: A colorless, odorless, flammable gas consisting
of the hydrocarbons (CH4) and resulting from the decay of vegetable
matter or manure due to the action of anaerobic bacteria in swampy land,
closed landfills or sewage disposal plants.
microbicide: A substance that destroys microorganisms.
microfiltration: The separation or removal from a
liquid of particles and microorganisms in the size range of 0.1 to 2.0
microns in diameter.
micrograms per liter: Considered as equal to parts
per billion (ppb). The common symbol for micrograms per liter is ug/L.
micron: A metric unit of length equal to one millionth
of a meter or one thousandth of a millimeter or about 0.00003937 inches.
The symbol for micron is the Greek letter u.
micron rating: A measurement applied to filters or
filter media to indicate the particle size at which suspended solids
above that size will be removed. As used in the water treatment industry
standards, this may be an absolute rating or a nominal rating.
micronutrient: see trace element.
microorganism: A living organism invisible or barely
visible to the naked eye and generally observed only through a microscope.
Also called a microbe. Microorganisms are generally considered to include
algae, bacteria, fungi, protozoa and viruses.
microwatt-seconds per square centimeter: A unit of
measurement of intensity and retention or contact time in the operation
of ultraviolet systems.
mineral: An inorganic (non-living) substance which
occurs naturally in the earth and has a composition that can be expressed
as a chemical formula and a set of characteristics (crystalline structure,
hardness etc.) common to all minerals. Examples of minerals are sulfur,
salt and stone.
mineral free water: Water produced by either distillation
or deionization. This term is sometimes found on labels of bottled water
as a substitute term for distilled or deionized water.
mineral water: Water which is naturally or artificially
impregnated with mineral salts or gases (carbon dioxide). The term is
also used to designate bottled water that contains no less than 250
ppm total dissolved solids (TDS) and originates from a protected ground
water source.
mixed bed: The intermix of two or more filter exchange
products in the same vessel during a service run.
mixed media: The use of two or more media products
in a single filtration loose media bed where the products are intermixed
- rather than in stratisfied layers. For example the intermix use of
calcite and magnesia in pH modification.
module: The membrane element and its housing in a
reverse osmosis unit.
molecule: The smallest particle of an element or compound
that retains all of the characteristics of the element or compound.
A molecule is made up of one or more atoms.
monitoring light sensor: An indicator light, electrically
or electronically activated, which is positioned in the effluent (product
water) stream of a piece of water treatment equipment to detect and
signal changes in the water quality which might malfunction of the equipment.
municipal water: Water that has been processed at
a central plant to make it potable or "safe to drink" and
which is then distributed to homes and businesses via water mains. The
term is a general one used to refer to the common source of water in
most urban and suburban areas - as opposed to water obtained from separate
proprietary sources such as private wells.
nanofiltration: A membrane treatment process which
falls between reverse osmosisand ultra filtration on the filtration/separation
spectrum.
naturally soft water: Ground surface, or rain water
sufficiently free of calcium and magnesium salts so that no curd will
form when soap is used and no calcium or magnesium based scale will
form when the water is heated.
natural sparking water: Carbonated water whose carbon
dioxide content is from the same source as the water itself.
neutral: (water chemistry) The midpoint (neutral)
reading of 7.0 on the pH scale, indicating that the solution (water)
producing the neutral reading will produce neither an acid nor alkaline
reaction. A 7.0 reading on the pH scale means that there are an equal
number of free hydrogen (acidic) ions and hydroxide (basic) ions.
nitrate: A natural nitrogen compound sometimes found
in well or surface waters. In high concentrations, nitrates can be harmful
to young infants.
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nominal filter rating: Filter rating indicating the
approximate size particle, the majority of which will not pass through
the filter. It is generally interpreted as meaning that 85% of the particles
of the size equal to the nominal filter rating will be retained by the
filter.
non degradable: Resistant to decomposition or decay
by biological means such as bacteria action or by chemical means such
as oxidation, heat, sunlight or solvents.
nonpathogenic: Not disease producing.
normal flow filtration: The flow of the entire feed
water stream in one direction directly through the filter media.
not detectable: A term used in reporting test results
to mean that the substance being tested cannot be detected by the equipment
or method being used for this particular test. This term implies that
it is possible that trace amounts may be present in quantities to small
to be detected by the test equipment or method.
NTU: nephelometric turbidity unit.
nucleus: The positively charges central part of an
atom containing nearly all of the atomic mass a consisting of protons
and neutrons (except in hydrogen which consist of one proton only).
nutrients: Elements or compounds essential as raw
materials for organism growth and development.
operating pressure: The manufacture's specific range
of pressure expressed in pounds per square inch (psi) within which a
water processing device or water system is designed to function. A range
of 30 to 100 psi is often indicated. Also called working pressure.
operating temperature: The manufacturer's recommended
feed water or inlet water temperature for a water treatment system.
organic: Having the characteristics of or being derived
from a living organism, plant and animal. Containing carbon (although
a few very simple carbon compounds such as carbon oxides, the carbides,
carbon disulfides and metallic carbonyls and carbonates are considered
inorganic).
organic matter: Substances consisting of or derived
from plant or animal matter, as opposed to inorganic matter which is
derived from rocks, ore and minerals. Organic matter is characterized
by its carbon hydrogen structure.
orfice: An opening, such as a hole or vent in something.
osmosis: The natural tendency for water to spontaneously
pass through a semipermeable membrane separating two solutions of different
concentrations (strength). The water will naturally pass from the weaker
(less concentrated) solution containing fewer particles of dissolved
substance to the stronger (more concentrated) solution containing more
particles of a dissolved substance. Thus natural osmosis causes the
stronger solution to become more diluted and tends to equalize the strength
of the solution on both sides of the membrane.
osmotic pressure: The pressure and potential energy
difference which exists between two solutions on either side of a semipermeable
membrane because of the tendency of water to flow in osmosis.
oxidizing agent: A chemical substance that gains
electron (is reduced) and brings about the oxidation of other substances
in chemical oxidation and reduction (redox) reactions.
ozonation: The process of feeding ozone into a water
supply for the purpose of decolorization, deodorization, disinfectant
or oxidation.
ozone (03): A very strong oxidizing agent which is
unstable and must be generated on site. Ozone is a highly reactive form
of oxygen and can be produced by sending a high voltage electrical discharge
through air or oxygen (such as occurs in a lightening storm). Ozone
can also be produced by some types of ultra violet lamps. Ozone is an
excellent oxidizing agent and bactericide.
particle: A very tiny, separate subdivision matter.
particle filtration: Filtration of particles in the
size range of 2 microns or larger in diameter. Particle filtration is
typically handled by cartridge filters and media filters.
particle size: As used in water industry standards,
this term refers to the size expressed in microns, of a particle suspended
in water as determined by the smallest dimension.
parts per billion (ppb): A measure proportion by weight
which is equivalent to one unit weight of solute (dissolved substance)
per billion unit weights of the solution.
parts per million (ppm): A measure of proportion by
weight which is equivalent to one unit of weight of solute (dissolved
substance) per million weights of solution. Since one liter of water
weighs one million milligrams, one ppm is equal to one milligram per
liter (mg/L). PPM is the preferred unit of measure in water or wastewater
analysis.
pathogens: Any disease producing organism.
pathogenic: Capable of causing disease.
percent recovery: The percentage of the feed water
which becomes product water. Determined by the number of gallons (or
liters) of product water divided by the total gallons (or liters) of
feed water and multiplied by100. The percent recovery is called recovery
rate in reverse osmosis and ultra filtration.
percent rejection: (reverse osmosis/ultra filtration)
The percentage of TDS in the feed water that is prevented from passing
the membrane with the permeate. The formula used is: the difference
obtained from the TDS in permeate divided by TDS in feed water; then
multiply the answer obtained by 100 to obtain a percentage.
permeate: That portion of the feed water which passes
through the membrane to become product water.
pH (potential of hydrogen): A measure of the degree
of the acidity or the alkalinity of a solution as measured on a scale
("pH scale") of 0 to 14. The midpoint of 7.0 on pH scale represents
neutrality, that is, a neutral solution is neither acid nor alkaline.
Numbers below 7.0 indicate acidity; numbers above 7.0 indicate alkalinity.
It is important to understand that pH is a measure of intensity, not
capacity. That is, pH indicates the intensity of alkalinity in the same
way temperature tells how hot something is but not how much heat the
substance carries.
phosphate: A salt of phosphoric acid. In the water
treatment industry, poly phosphates are used a sequestering agents to
control iron and hardness, and as a coating agent to control corrosion
by formation of a thin passivating film on metal surfaces.
point of entry (POE) treatment: Full service water
treatment at the inlet to an entire building or facility (outside faucets
may be excepted from treatment).
point of use (POU) treatment: Water treatment at a
single outlet or limited number of water outlets in a building, but
for less than the whole building or facility. POU treatment is often
used to treat water for drinking and cooking only.
polishing filter: A filter installed for use after
the primary water treatment stage to remove any trace of undesirable
matter or to polish the water.
pollutant: A contaminant existing at a concentration
high enough to endangered the environment or the public health or to
be otherwise objectionable.
polyphosphate: A form of phosphate polymer consisting
of a series of condensed phosphoric acids containing more than one atom
of phosphorous. Polyphosphate is used as a sequestering agent to control
iron and hardness, and as a coating agent that forms a thin passivating
film on metal surfaces to control scale.
porous: Full of pores through which water, light etc
may pass.
porosity: A measure of the volume of pores in a material.
Porosity is calculated as a ration of the interstices of material (e.g.
the volume of spaces between the media particles in a filter bed) to
the volume of its mass, and is expressed as a percentage.
potable (drinking) water: A water supply which meets
U.S. EPA and/or state water quality standards and is considered safe
and fit for human consumption.
potassium chloride (KCl): A colorless potassium salt
which can be used as a regenerant in cation exchange water softeners.
pounds per square inch (psi): unit of measure for
expressing pressure.
pretreatment: Any water treatment step performed prior
to the primary treatment process, such as filtration prior to deionization.
pressure differential: The difference in the pressure
between two points is a water system. The difference may be due to the
difference in elevation and/or to pressure drop resulting from water
flow.
pressure drop: A decrease in the water pressure (in
psi) which occurs as the water flows. The difference between the inlet
and outlet water pressure during water flow through a water treatment
device.
process water: Water used in a manufacturing or treatment
process or in the actual product manufacture.
production rate: The amount (gallons or liters) of
product water the system produces per minute or (especially for reverse
osmosis) per 24 hour period.
product water: Water that has been through the total
treatment process and meets the quality standards required for the use
to which the water will be used.
prototype: an original water treatment equipment unit
on which a specific equipment line is modeled.
protozoa: Microscopic, usually single celled microorganisms
which live in water and are relatively larger in comparison to other
microbes. Protozoa are higher on the food chain than the bacteria that
they eat. Many protozoa are parasitic.
pure water: This term has no real meaning unless the
word "pure" is defined by some standard such as pharmaceutical
grade water.
purified water: A USP grade water produced from water
meeting U.S. EPA standards for potable drinking water which has microbiological
content under control and is free from foreign substances.
putrefaction: The decomposition (rotting) of organic
matter caused by microbes and oxidation.
pyrogens: Substances (often of unknown origin) that
produce fever when introduced into the human body. Being chemically
and physically stable, pyrogens are not necessarily destroyed by conditions
that kill bacteria
qualification test: Test and verifications performed
to validate water treatment equipment conformance to a specific standard.
quartz sleeve or quartz jacket: A clear, pure fused
quartz tube used to protect the high intensity ultraviolet lamps in
ultraviolet systems. It usually retards less than 10% of the ultraviolet
radiation dose.
radial flow: The flow pattern in which water flows
from the outside of a filter element to the center core.
radical: A group of atoms acting as a single atom
which go through chemical reactions without being changed.
radon (Rn): A colorless, odorless, short lived radioactive
gas which is produced by decay of the uranium/radium series and is soluble
in water. Radon is considered carcinogenic when inhaled by humans. Radon
can be removed from water by aeration or activated carbon.
rated capacity (filtration or adsorption): The manufacturer's
statement regarding the expected number of days the equipment will be
in service or the expected number of gallons of product water is delivered
before backwash, rinse or replacement is needed.
rated pressure drop: The expected pressure drop in
psi as stated by the equipment manufacturer or obtained under test conditions.
rated flow rate: The specified maximum and minimum
flow rate at which a particular piece of water treatment equipment will
continuously produce the desired quality of water.
raw water: Water, usually from wells or surface sources,
which has had no previous treatment and is entering the water processing
system or device. The water at the inlet side of any water treatment
device.
redox: A shortened term for "oxidation-reduction".
Used in terms such as redox reactions and redox conditions.
regeneration (ion exchange, softening): The use of
a chemical solution (regenerant) to displace the contaminant ions deposited
on the ion exchange resin during the service run and replace them with
the kind of ions necessary to restore the capacity of the exchange medium
for reuse.
reject water: A term used in distillation, reverse
osmosis and ultra filtration to describe that portion of the incoming
feed water that has passed across the membrane but has not been converted
to product water and is being sent to drain.
rejection rate: In a reverse osmosis or ultra filtration
system, rejection rate is the quantity of feed water that does not pass
through the membrane expressed as a percent of the total quantity of
incoming fed water.
removable: capable of being taken away from a water
treatment equipment unit using only simple tools such as a screw driver,
pliers, or open ended wrench. Readily removable indicates capable of
being taken away from a water treatment unit without the use of tools.
reservoir tank: Same as storage tank on a reverse
osmosis system.
residential equipment: The term sometimes used to
denote smaller sized water processing equipment which has been designed
primarily for home use.
residual: The amount of a specific material which
remains in the water after the water has been through water treatment
step.
residual chlorine: Chlorine allowed to remain in a
treated water after a specified period of contact time and allowed to
provide disinfection protection through out the distribution system.
The amount of residual chlorine is the difference between the total
chlorine added and that consumed by the oxidizable matter.
resin: As used in the water processing industry, this
term refers to ion exchange resin products which are usually specifically-manufactured
organic polymer beads used in softening and other ion exchange processes
to remove dissolved salts from water.
reverse osmosis (RO): A water treatment process that
removes undesirable materials from water by using pressure to force
the water molecules through a semipermeable membrane. This process is
called "reverse" osmosis because the pressure forces the water
to flow in the reverse direction (from the concentrated solution to
the dilute solution) to the flow direction (from the dilute to the concentrated)
in the process of natural osmosis. RO removes ionized salts, colloids
and organic molecules down to a molecular weight of 100.
rust (ferric oxide): A reddish corrosion product occasionally
found in water. Rust is formed as a result of electrochemical interaction
between iron and atmospheric oxygen in the presence of moisture.
safe water: see potable water.
saline: Consisting of, or containing salt.
salt water: The general term for all water over 1,000
ppm (mg/L) total dissolved solids.
sand filter: The oldest and most basic filtration
process, which generally uses two grades of sand (coarse and fine) for
turbidity removal or as a first stage roughing filter or pre-filter
in more complex processing systems.
scale: A coating or precipitate deposited on surfaces
such as kettles, water pipes or steam boilers that are in contact with
hard water. Waters that contain carbonates or bicarbonates of calcium
or magnesium are especially likely to cause scale when heated.
scavenger: (water treatment) A polymer matrix or ion
exchanger that is used specifically to remove organic species from the
feed water before the water is to pass through the deionization.
screen size: SEE mesh size.
selectivity: The tendency of an ion exchanger to "prefer"
(have more attraction for) certain kinds of ions over others, as if
the resin were ranking the types of ions in order to be removed; most
preferred ion, second most preferred, etc..
septic: Producing or characterized by bacterial decomposition.
serial filtration: The arrangement of two or more
filtering steps, one following the other, in order to remove increasingly
finer particles at each stage and provide for filtration of all sizes
of suspended solids.
service flow: The rate in U.S. gallons per minute
(gpm) or liters per minute (L/min) at which a given water processing
system can deliver product water. The rating may be intermittent peak
flow or constant flow.
shallow well: A well sunk in easily penetrated ground
to a point which is below the water table but usually less than about
30 feet in depth.
silt density index (SDI): A test used to measure the
level of suspended solids in feed water for membrane filtration systems.
single stage system: A filtering system that uses
only a single filtering cartridge.
slug: A temporary abnormally high concentration of
an undesirable substance which shows up in the product water.
slurry: A thin watery mixture of a very fine insoluble
substance.
soda water: water which has impregnated with carbon
dioxide (CO2)so that it will be effervescent when not under pressure.
Same as seltzer water.
sodium: (Na+): A metallic element found abundantly
in compounds in nature, but never existing alone.
sodium chloride (NaCl): The chemical name for common
table salt.
soft water: Any water which normally contains less
than 1.0 grain per gallon (17.1 mg/L or ppm) of total hardness expressed
as calcium carbonate equivalent.
softened water: Any water which has been processed
in some manner to reduce the total hardness to 17.1 mg/L or ppm (1.0
grain per gallon) or less expressed as calcium carbonate equivalent.
solids: The matter dissolved or suspended in water
or wastewater.
spiral wound: A very common construction configuration
for one style of reverse osmosis membrane and cartridge filter element.
In RO membranes, the membrane sheets are assembled in layers around
a perforated mandrel product water tube with coarse mesh spacers screens
between the layers, to form a complete module element. In cartridge
filter elements, the filtration material such as fiber cord, is continually
would around a perforated mandrel core tube.
spore: A small reproductive body, often single celled,
capable of reproducing the organism under favorable conditions. The
spore is sometimes considered the resting stage of the organism. Among
the organisms that may produce spores are algae, bacteria and certain
protozoan. In water, most spores resist adverse conditions which would
readily destroy the parent organism.
spring: A place where ground water flows naturally
from the soil or rock formation onto the land surface or into a body
of surface water. A spring is sometimes used as a source of water for
a shallow dug well.
static: Fixed in a position, resting, without motion.
storage capacity: The maximum volume of water available
for use from the water storage tank, e.g. the amount available from
a RO or distiller water storage tank.
string wound element: A cartridge style element constructed
by continuous spiral winding of natural or synthetic yarn around a pre-formed
product water tube core and then building it up in layers to form a
depth type filter.
submicron filter: A cartridge type membrane filter
used in fine particle separation applications to remove particles of
less than one micron in size.
sulfur (S): A yellowish solid chemical element. "Sulfur"
is also often used to refer to sulfur water.
sulfur bacteria: Thio-Bacillus
sulfur water: water containing objectionable amounts
of hydrogen sulfide gas which causes an offensive "rotten egg"
odor.
surface filtration: Filtration that occurs at the
surface layer (as opposed to within the body depth) of the filter and
is accomplished by passing the material to be filtered over a grating
screen, sieve or membrane fabric with micro sized holes. The size of
the holes in the filter determines what materials will pass through
and what will filter out (held back).
surface water: All of the water (fresh and salt) on
the surface of the earth including streams, lakes oceans, rivers, glaciers
and some shallow wells that can be fed by surface runoff water.
system: A complete integrated series consisting of
various components and perhaps multiple water treatment processes which
can be tested, installed and operated as a single unit of equipment.
For example, a single RO treatment system generally consists of two
or more stages of media filtration plus cross flow membrane filtration
and water storage.
taste threshold: The minimum concentration of a chemical
or biological substance which can just be tasted.
TCE: trichloroethylene.
TDS: total dissolved solids.
teflon: The trade name of a high temperature industrial
plastic material used in cooking, finishes, bearings, lubricating, plumbing
sealants, and a practically inert coating on metal and glass surfaces.
TH: Total hardness.
Thin film composite membrane (TFC): A class of reverse
osmosis membranes made with polyamide-based polymer and fabricated with
different materials in the separation and support layers.
THMs: Trihalomethanes.
Thiobacillus: A small single celled sulfur bacterium
which can create hydrogen sulfide gas and the resulting "rotten-egg"
odor in water supplies.
tortuous path: Water flow through channels which are
constricted and marked by repeated twists, bends and winding turns.
total chlorine: The total concentration of the chlorine
in a water, including the combined available chlorine and the free available
chlorine.
total dissolved solids (TDS): The total weight of
the solids that are dissolved in the water, given in ppm per unit volume
of water. TDS is determined by filtering a given volume of water (usually
through a 0.45 micron filter), evaporating it at a defined temperature
(usually 103 - 105 degrees Celsius) and then weighing the residue.
total hardness (TH): The total of the amounts of divalent
metallic cations, principally calcium hardness and magnesium hardness,
expressed in terms of calcium carbonate equivalent.
total matter: The sum of all suspended and dissolved
matter in a water sample.
total solids (TS): The weight of all organic and inorganic
solids, both dissolved and suspended, per unit volume of water.
toxic: Poisonous (to human beings); capable of producing
disease or otherwise harmful to human health when taken into the body.
trace element: An element essential to plant and/or
animal nutrition in trace concentration of 1% of less.
trace substance (or trace): A substance which is found
during water analysis in a small concentration, high enough to be detected
, but to low to be quantified accurately by standard testing methods.
transpiration: The process of plants giving off watery
vapor from their leaves and other surfaces.
trichloroethylene (TCE): A toxic volatile organic
compound often found as a solvent.
trihalomethanes (THMs): A group of organic chemicals,
suspected of being carcinogenic, which are formed in water when chlorine
being used as a disinfectant reacts with natural organic matter such
as humic acids from decayed vegetation.
turbidity: The amount of small particles of solid
matter suspended in water as measured by the amount of scattering and
absorption of light rays caused by the particles. Turbidity is measured
in nephelometric turbidity units (NTU). Potable water should not exceed
0.5 NTU.
ultrafiltration: A method of cross-flow filtration
(similar to reverse osmosis but using lower pressure) which uses a membrane
to separate small colloids and large molecules from water and other
liquids.
ultrapure water: Highly treated water that is deionized
and mineral free with high resistivity and no organics; it is usually
used in the semiconductor and pharmaceutical industries. Ultrapure water
in NOT considered biologically pure (potable) or sterile.
ultraviolet (UV): Pertaining to ultraviolet light.
ultraviolet chamber: The area where the water is irradiated
with ultraviolet rays.
ultraviolet demand: The amount of ultraviolet rays
required to inactivate certain microorganisms.
ultraviolet dosage: The amount of disinfectant ultraviolet
rays delivered to the organisms in the water being disinfected. Dosage
is a combination of UV intensity times the contact time and is measured
in watt-seconds per square centimeter.
ultraviolet (UV) light: Radiation (light) having a
wavelength shorter than 3900 angstroms, the wavelengths of visible light,
and longer than 100 angstroms, the wavelength of x-rays.
uniform flow: A flow in which the feet per second
velocity rates and directions are the same from point to point along
the conduit.
up flow: A pattern of water flow in which a solution
(water or regenerant usually) enters at the bottom of the vessel or
column and flows out at the top of the vessel or column during any phase
of the treatment unit's operating cycle.
user: The product water consumer.
vacuum distillation: Distillation that occurs at a
pressure somewhat below atmospheric pressure. Lowering the pressure
also lowers the boiling point of water, thus conserving energy by requiring
less heat to bring about distillation.
validation: Determination upon testing that a representative
sample of a water treatment product/model has meet the requirements
of a specific standard.
vapor: The gaseous form of any substance whose usual
form is liquid or solid. Visible particles of moisture suspended in
air, such as mist or fog.
velocity: The time measurement of linear motion (flow)
in a given direction. For example, water flowing 60 feet in a conduit
each minute has a velocity of 60 feet per minute (fpm) or one foot per
second ( 1 fps).
viable: capable of living independently and being
reproductive.
viable water treatment process: A water or wastewater
treatment process capable of accomplishing the desired water quality.
virus: A parasitic infectious microbe, composed almost
entirely of protein and nucleic acids, which can cause disease(s) in
humans. Viruses can reproduce only within living cells. They are 0.004
to 0.1 micron in size, about 100 times smaller than bacteria.
VOCs: Volatile organic chemicals.
volatile: Capable of becoming vapor at relatively
low temperatures.
volatile organic chemicals (VOCs): Synthetic organic
chemicals that turn into vapor at relatively low temperatures.
wastewater: Water that has been used. RO, ultrafiltration,
electrodialysis The stream of water (not product water) created as a
result of processing water -the reject water or condensate.
water (H2O): The liquid that descends from the clouds
as rain and forms lakes, streams and seas (ocean). Water is a major
constituent of all living matter. An odorless, colorless, tasteless
liquid which exists as ice in solid form (phase) and steam in vapor
form (phase). It freezes at 32 degrees F/0 degrees C and boils at 212
degrees F/100 degrees C.
waterborne disease: A disease, caused by bacterium
or organism able to live in water, which can be transmitted by water.
water closet: A flushable toilet.
water conditioning: The treatment or processing of
water, by any means, to modify enhance or improve its quality to meet
a specific water quality need desire or set of standards. Also called
water treatment.
water softening: The reduction /removal of calcium
and magnesium ions, which are the principal cause of hardness in water.
water source: The basic origin of a water , either
a surface source (such as lake, river or reservoir) or a subsurface
source ( such as well). After treatment and pumping via pipelines, the
treated and pumped water becomes a water supply.
water table: The level of the top of the zone of groundwater
saturation.
watertight: A condition existing in water treatment
equipment and materials of such precision of construction and fit as
to be impermeable to water unless sufficient pressure occurs to cause
rupture.
WHO: World Health Organization.
x-rays: Electromagnetic radiation with a very short
wavelength (0.01 to 12 nanometers), shorter than ultraviolet radiation.
yield: the amount of product water produced by a water treatment process.
zeolites: Hydrated sodium alumina silicates, either
naturally occurring mined products or synthetic product, with ion exchange
properties.
zero soft water: Water produced by cation exchange
process and measuring less than 1.0 grain per U.S. gallon (17.1 ppm
or 17.1 mg/L) as calcium carbonate.
zone of saturation: The layer in the ground in which
all available interstitial voids, cracks, crevices, holes are filled
with water. The level of the top of this zone is the water table.
