Water Quality
Glossary
of Water Quality Terms
M
Mainstem
The main course of a river or stream where
most of the water flows most of the time.
Marine
Refers to the ocean or to a sea, saltwater.
Marsh
A wetland that is usually submerged in shallow
water and whose vegetation is dominated by
herbs.
Maximum
contaminant level, MCL
The greatest amount of a contaminant that
can be present in water without causing a risk to its intended use, the maximum
level of a contaminant allowed in water to maintain aquatic life,
to minimize
pollution, to permit recreation or allow the water to be used
as a drinking
water source, (see contact recreation, non-contact
recreation).
MCL,
Maximum contaminant level
The greatest amount of a contaminant that
can be present in water without causing a risk to its intended
use, the maximum
level of a contaminant allowed in water to maintain aquatic life,
to minimize pollution, to
permit recreation or allow the water to be used
as a drinking
water source, (see contact
recreation, non-contact
recreation).
Meiosis
The process of cell division which separates
the pair of complementary chromosomes to
produce eggs and sperm with only one set
of chromosomes each.
Metalloid
Resembling a metal, or having chemical properties
similar to metals.
Methylation
The process whereby a compound is modified
chemically, often through bacterial action, by the replacement of a hydrogen
atom by a methyl group, -CH3.
Mg/L,
Milligrams per litre
A concentration unit of chemical constituents
in solution, the weight of solute per unit
volume
of solvent, usually water, this measure is
equivalent to parts per million or ppm.
Micrograms
per litre, µ/L
A concentration unit
of chemical constituents in solution; the weight of solute per unit volume of
solvent, usually water, one thousand micrograms per
liter is equivalent to 1
milligram per litre, this measure is equivalent to parts per billion or ppb.
Micron, µ
A quantitative measure of thickness equal
to one millionth of a meter, one thousandth of a millimeter, one ppm.
Milligrams
per litre, Mg/L
A concentration unit of chemical constituents
in solution, the weight of solute per
unit
volume
of solvent, usually water,
this measure is
equivalent to parts per million or ppm.
Mitochondria
The organelles
in eukaryotic cells that carry out terminal respiration, specialized structures
that carry out respiration and store energy.
Mollusca
An organism in the invertebrate Phylum Mollusca,
a major group of marine, aquatic and
terrestrial animals which are soft bodied
and usually have a hard shell, examples are clams,
mussels, snails, octopus and squid.
Monitoring
To check, measure or examine water
quality over a period of time to note any changes which
may occur.
Most
Probable Number, MPN
The statistically determined number that
represents the number of individual bacteria most likely to have been present
in a given sample, measurement of fecal coliform indicator
bacteria based on
gas production in tubes, alternative to the standard fecal coliform test involving
filtration and culture on disk media.
MPN, Most
Probable Number
The statistically determined number that
represents the number of individual bacteria most likely to
have been present
in a given sample, measurement of fecal coliform indicator
bacteria based on gas production
in tubes, alternative to the standard fecal coliform test involving filtration and
culture on disk media.
Municipal
sewage
Sewage from a community which may be composed
of domestic sewage, industrial wastes
or both.
Muscle
Tissue consisting of cells
which are highly
contractile, most of the edible portions of animal flesh
is muscle.
Muskeg
A wetland or peatland such
as a fen or bog that accumulates peat and whose
vegetation is
dominated by sphagnum moss and small shrubs
or herbs.
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N
Nekton
Aquatic animals in the water
column with
sufficient powers of locomotion to overcome currents and go where they want under
their own power as opposed to the plankton which, although some are motile, are
at the mercy of water currents, fish are examples of the nekton.
Nephelometric
turbidity unit, NTU
The unit of measure for the turbidity of
water, a measure of the cloudiness of water as measured by a nephelometer, based
on the amount of light that is reflected off particles in the water.
Non-consumptive
use
Using water in a way that does not reduce
the immediate supply such as hunting, fishing, boating, water-skiing, swimming
and some power production, (see consumptive use).
Non-contact
recreation
Recreational pursuits not involving a significant
risk of water ingestion, including fishing, commercial and recreational boating,
and limited body contact incidental to shoreline activity, (see contact
recreation).
Non-filterable
residue
Solids that are not in true solution and
that can be removed by filtration they usually contribute directly to turbidity,
small particles of solid pollutants that resist separation by conventional methods;
operationally greater than 0.45 microns in size; also known as suspended
solids,
suspended matter or suspended sediment.
Non-point
Source Pollution, NPS
Constituents in water, including pollutants,
originating from diffuse, land-based sources and generally transported in runoff from
precipitation, pollution
discharged over a wide land area, not from one
specific location, diffuse pollution caused by sediment, nutrients, organic and
toxic substances originating from land-use activities, which
are carried to lakes and streams by surface
runoff, contamination that occurs when rainwater, snowmelt or irrigation washes
off plowed fields, city streets or suburban backyards. As
this runoff moves across the land surface, it picks up soil particles and pollutants,
such as nutrients and pesticides, source of pollution in which wastes are not
released at one specific, identifiable point but from a number of points that
are spread out and difficult to identify and control, (see point
source
pollution).
Non-porous
A material which does not allow water to
pass through it, (see porous).
Non-potable
Not suitable for drinking due
to toxins, pathogens or aesthetics, (see potable).
NTU, Nephelometric
turbidity unit
The unit of measure for the turbidity of
water, a measure of the cloudiness of water as measured by
a nephelometer, based on the amount of light that is reflected off particles
in the water.
Nutrient
A substance, element or compound, necessary
for the growth, development and reproduction of plants
and animals, as a pollutant any element or compound, such as
phosphorous or nitrogen that encourages abnormally
high organic growth in ecosystems, (see eutrophic).
Nutrient
cycle
Chemical transformations of nitrogen, phosphorus,
silica and other essential elements in continuous cycles between organic and
living systems and inorganic and non-living phases in an ecosystem as organisms
grow and die.
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O
Ocean
The large, permanent body of saline water
surrounding the continents and covering most of the
surface of the earth.
Oligochaetes
Primarily fresh water or terrestrial hermaphroditic
annelid worms that lack a distinctive head segment, (see worms, polychaetes).
Oligotrophic
Having a low supply of nutrients and thus
a low productivity or biomass, (see eutrophic).
Organelles
The structures in eukaryotic cells, notably
chloroplasts and mitochondria, specialized structures that carry out respiration,
photosynthesis and other functions in the cell.
Organic
chemicals or compounds
Usually chemicals or compounds which contain
carbon atoms; usually chains of carbon atoms connected directly to each other,
chemicals containing carbon, organic matter, plant and animal residues, or substances
made by living organisms.
Organic
contaminants
Organic chemicals which are toxic to organisms;
they may be persistent and mobile in the
environment.
Osmosis
The movement of water molecules through a
thin membrane while leaving the dissolved salts behind, the process occurs in
our bodies and is also a technical and commercial method of removing salts from
saline water.
Outfall
The end of the pipe leading from a sewage treatment
plant which delivers the wastewater to the environment,
often via a
diffuser, the discharge point for a wastewater
flow, for example from a sewage treatment
plant or refinery, the place where a wastewater treatment plant discharges treated
water into the environment, the place where a sewer, drain,
or stream
discharges, the outlet or structure
through which reclaimed water or
treated
effluent is finally discharged to
a receiving
water body.
Oviparous
Fish and other organisms that produce eggs which
hatch externally, fertilization may be
internal or external, the fertilized
eggs are self-contained and receive no nutrients from
the
mother.
Ovoviviparous
Fish and other organisms that produce eggs which
hatch internally, fertilization is internal, the
fertilized eggs are self-contained and receive
no further nutrients from the mother.
Oxidation
Literally — combining with oxygen,
chemically — transfer of electrons in a chemical reaction.
Oxygen
demand
The need for molecular oxygen to meet the
needs of biological and chemical processes in water, even though very little
oxygen will dissolve in water, it is extremely important in biological and chemical
processes, (see BOD, biochemical oxygen demand).
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P
PAHs,
Polycyclic aromatic hydrocarbons
A family of organic compounds with several
linked aromatic rings in their structure which are derived from the combustion
of fossil fuels, the higher molecular weight PAHs are an environmental concern
due to their bioaccumulation in organisms and their toxic and carcinogenic activity.
Palustrine
Relating to a freshwater environment, such
as a marsh, fen, lake, pond, river, bog or swamp.
Parasite,
parasitic
Organisms that are pathogens and
are obliged
to live on or in other organisms, often causing
disease or death.
Particulate
Consisting of many small individual particles,
not dissolved.
Pathogen
An organism, generally a microorganism, causing,
or capable of causing, disease or death, a disease-producing agent, usually applied
to a living organism, any worms, protozoans, viruses, bacteria or fungi that
cause disease.
Pathogenic
Causing, or capable of causing, disease or
death, generally applied to microorganisms.
PCBs,
Polychlorinated biphenyls
Man-made liquid chemicals that are stable,
non-corroding, fire resistant, toxic and relatively
non-biodegradable, once used
in electrical transformers because of these properties and in
paint, composed of two joined
phenol molecules that have chlorine atoms replacing
many of the hydrogen atoms,
frequently found in industrial wastes, and subsequently
in surface water and ground
waters, accumulate in the environment, particularly in
the sediment where they can remain
indefinitely, virtually banned in 1979 but continuing to appear
in the flesh of fish and other animals.
Peak
flow
The maximum instantaneous discharge of
a
stream or river at a given location, usually
occurs
at or near the time of maximum height.
Peatland
A wetland such as a fen or bog that
accumulates
peat and whose vegetation is dominated by
sphagnum moss and small herbs.
Pelecypoda
Bivalves, class of aquatic molluscs with
two shells.
Percolation
The movement of water through the subsurface
soil layers, usually continuing downward to the
ground water
or water table, the oozing or soaking of water
through the soil, the movement of water
through the openings in rock or soil, the entrance of a portion
of the streamflow into the channel
materials to contribute to ground water replenishment.
Periphyton
Organisms attached to and growing on structures,
sediments or organisms submerged in water.
Permeability
The ability of a water bearing material to
transmit water, measured by the quantity of water passing through a unit cross
section, in a unit time, the ability of a material to allow the passage of a
liquid, such as water through rocks, materials, such as gravel and sand, allow
water to move quickly through them, whereas impermeable materials, such as clay,
do not allow water to flow freely.
pH
The numeric value which is the negative reciprocal
of the logarithm, in base 10, of the hydrogen ion concentration in moles per
litre, a quantitative expression for the amount of acidity or alkalinity of a
solution, the scale ranges from 0 to 14, where pH 7 is neutral, less than 7 is
acid, more than 7 is alkaline or basic, numeric value that describes the intensity
of the acid or basic, alkaline, conditions of a solution.
Phenol
A benzene ring with one of the hydrogens
replaced by a hydroxyl or -OH group.
Photic
zone
The upper portion of the water column which
admits sufficient light for photosynthesis, the photic zone is reduced with increased
turbidity.
Photosynthesis
The process by which the chlorophyll-bearing cells
of green plants, in the presence of light, convert carbon dioxide and water into
sugar, an organic compound, with the evolution of oxygen, incorporation of solar
energy into carbon compounds by green plants, ultimately providing energy and
oxygen for the vast majority of life on earth.
Phytoplankton
The photosynthetic portion, primarily algae,
of the free-floating community of small, mostly microscopic, organisms in water,
collectively called plankton.
Plankton
The total free-floating community of small,
mostly microscopic, organisms in water, some are
motile but all are at the mercy of water
currents, (see nekton).
Planktonic
Drifting unattached in water, the plankton include
both plants and animals ranging from
microscopic to macroscopic.
Plume
A portion of a water body which is distinguishable
from the remainder because it is not completely mixed and its characteristics
are measurably different, generally downstream from the junction of another stream of
water from a tributary or waste
discharge, the area taken up by contaminants in an aquifer.
Poikilothermic
Animals which do not automatically control
their own body temperature at some fixed value,
cold-blooded animals, their body
temperature is controlled by ambient conditions or by behaviour, (see homeothermic).
Point
source pollution
Source of pollution that
involves discharge of wastes from an identifiable
point, such as a smokestack or sewage treatment plant, water pollution coming
from a single point, such as a sewage outflow pipe,
(see non-point source pollution).
Pollutant
Waste material which causes
harm to organisms directly or to their environment.
Pollution
Causing the release of a pollutant into the
environment, harmful or undesirable changes in the physical, chemical, or biological
characteristics of the air, water or land that may affect the health, survival
or activities of human or other living organisms, degradation of the environment
by a substance or condition to such a degree that the environment fails to meet
specified standards or cannot be used for a specific purpose.
Polychaetes
Primarily marine annelid worms with
paired
segmental appendages, separate sexes and free-swimming trochophore
larvae, worms of
the Class Polychaeta of the invertebrate worm order
Annelida, dominant in marine
benthos, highly diversified, ranging from detritivores to predators,
some species
serving as good indicators of environmental stress, (see oligochaetes).
Polychlorinated
biphenyls, PCBs
Man-made liquid chemicals that are stable,
non-corroding, fire resistant, toxic and relatively
non-biodegradable, once used
in electrical transformers because of these properties and in
paint, composed of two joined
phenol molecules that have chlorine atoms replacing
many of the hydrogen atoms,
frequently found in industrial wastes, and subsequently
in surface water and ground
waters, accumulate in the environment, particularly in
the sediment where they can remain
indefinitely, virtually banned in 1979 but continuing to appear
in the flesh of fish and other animals.
Polycyclic
aromatic hydrocarbons, PAHs
A family of organic compounds with
several
linked aromatic rings in their structure which are derived
from the combustion
of fossil fuels, the higher molecular weight PAHs are an environmental
concern
due to their bioaccumulation in organisms and their toxic and carcinogenic activity.
Pond
A relatively small, sometimes ephemeral or
seasonal, inland body of fresh water occupying a
basin or hollow in the earth's surface.
Pore
water
The water found in the interstices of submerged
sediments, the basis of some types of toxicity
testing, since it is pore water to which
benthic organisms are exposed.
Porosity
A measure of the water-bearing capacity of
subsurface rock, with respect to water movement, it is not just the total magnitude
of porosity that is important, but the size of the voids and the extent to which
they are interconnected, as the pores in a formation may be open and interconnected,
or closed and isolated, clay may have a very high porosity with respect to potential
water content, but it constitutes a poor flow medium as an aquifer because the
pores are usually so small.
Porous
A material which allows water to pass through
it, (see nonporous).
Potable
Water that is toxicologically and pathologically safe
and aesthetically fit to drink, (see
non-potable).
ppb
A concentration unit
of chemical
constituents in solution; the weight of solute per
unit volume of solvent,
usually
water, one thousand micrograms per liter is equivalent to 1 milligram
per litre,
this measure is equivalent to parts per billion.
ppm
A concentration unit of
chemical
constituents in solution; the weight of solute per
unit volume of solvent,
usually
water, one thousand milligrams per liter is equivalent to 1
gram
per litre, this measure is equivalent
to parts per million.
ppt
A concentration unit of chemical constituents
in solution; the weight of solute per unit volume of solvent,
usually applied to marine, brackish or saline
water, this measure is equivalent
to parts per thousand.
Precipitate
A solid or particles which have come out
of an aqueous, or other fluid, solution.
Precipitation
Water, normally in the form or rain, snow
and hail, which falls from the atmosphere to the earth as part of the water cycle,
the process whereby solids or particle come out of solution.
Precision
This is an indicator of how close a series
of measured values come to each other, how tight is the cluster of values, regardless
of whether or not the values are accurate or reflect the actual or true value,
(see accuracy).
Primary
sewage treatment
The first stage of the wastewater treatment
process consisting of mechanical removal of large settleable solids through filtering,
screening and/or settling, primary
sewage treatment is a mechanical treatment
in which relatively large solids are removed from the sewage by settling out
as sludge, mechanical methods, such as filters and scrapers, are used to remove
pollutants, solid material in sewage also settles out in this process, (see secondary
sewage treatment, tertiary sewage treatment).
Primary
wastewater treatment
The first stage of the wastewater treatment
process consisting of mechanical removal of large settleable solids through filtering,
screening and/or settling, primary
wastewater treatment is a mechanical treatment
in which relatively large solids are removed from the sewage by settling out
as sludge, mechanical methods, such as filters and scrapers, are used to remove
pollutants, solid material in sewage also settles out in this process, (see secondary
sewage treatment, tertiary sewage treatment).
Pristine
Describes a natural system, water for example,
that has not been affected by anthropogenic
pollution.
Productivity
The total amount of biological material produced
over a defined time period, (see biomass,
standing crop).
Profundal
zone
The deep-water region of a lake that is not
penetrated by sunlight.
Prokaryotic
Unicellular organisms with a bacteria-like
cell structure, lacking a nucleus and some other eukaryotic organelles,
they
may have photosynthetic pigments but lack chloroplasts,
the specialized photosynthetic organelles in higher plants,
and mitochondria, (see eukaryotic).
Protozoan
Single-celled, nucleated, eukaryotic organisms,
lacking cell walls, generally microscopic, some
are photosynthetic.
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Q
Qualitative
Refers to what, which chemical or compound
or identity regardless of how much, (see
quantitative).
Quantitative
Refers to a measured value as how much, how
fast, how deep, how many or what
concentration, (see qualitative).
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R
Receiving
waters
A river, ocean, stream or
other watercourse into which wastewater or treated effluent is
discharged.
Recharge
Water entering an underground aquifer through
faults, fractures or direct absorption,
replenishing an aquifer.
Reclaimed
wastewater
Treated wastewater that
can be used for beneficial
purposes, such as irrigating certain plants,
domestic wastewater which
has been treated
to a quality suitable for a beneficial use.
Recycled
Using water or other materials more than
once before returning it to the natural environment,
wastes that are used for
a beneficial purpose or made into new product rather than being
landfilled or burned.
Recycled
water
Water that is used more than once before
it returns to the natural hydrologic system.
Red
tide
Algal bloom involving dinoflagellate
phytoplankton species, such as Gonyaulax monilata and Ptychodiscus
brevis, which
naturally manufacture biotoxins, can cause fish kills and several types of shellfish
poisoning in people.
Reservoir
A natural or artificial basin for collecting
and holding a supply of water, tanks, dammed areas,
lakes or underground aquifers,
where water
is collected and used for water storage, regulation
and control, large bodies
of ground water are called ground water
reservoirs, water behind a
dam is called a surface reservoir.
Residence
time
The period of time water
is retained in a reservoir, bay or other system,
based upon flow rates
into and out of the system, (see flushing).
Residual
chlorine
The unreacted chlorine which remains in solution after
the reactions with all the organic
compounds present have occurred.
Return
flow
That part of a diverted flow that is not
consumptively used and is returned to its original source or to another body
of water, drainage water from irrigated farmlands that re-enters the water system
to be used further downstream, irrigation water that is applied to an area and
which is not consumed in evaporation or transpiration and returns to a surface
stream or aquifer.
Reverse
osmosis, RO
A water treatment method whereby
water is forced through a semi-permeable membrane which filters out impurities,
similar in function to a kidney dialysis machine and used in most space programs
and navy vessels to turn waste water into potable water, removing salts from
water using a membrane, the product water passes through a fine membrane that
the salts are unable to pass through, while the salt
waste, brine is removed,
method of water or wastewater treatment that relies on a semi-permeable membrane
to separate waters from pollutants, an external force is used to reverse the
normal osmotic process resulting in the solvent moving from a solution of higher
concentration to one of lower concentration.
Riparian
zone
A stream and all the vegetation
on its banks
out to the high water mark, associated with the
bank of a watercourse, the woodlands bordering
a river.
River
A relatively large and usually permanent
flowing body of fresh water, in a defined channel.
Runoff
Surface flows
of water entering rivers, lakes,
the ocean or reservoirs, surface
water entering rivers,
fresh water lakes, or reservoirs,
the portion of precipitation that is not absorbed
into the soil, but flows
into surface streams, that part of the precipitation
or irrigation water that appears
in uncontrolled surface streams, rivers,
drains or sewers, direct runoff
or base runoff, storm
interflow or ground water runoff, total discharge
during a specified period of time, the depth
to which a drainage area would be covered if
all of the runoff for a given period of time
were uniformly distributed
over it.
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S
Saline
Waters having solute concentrations approaching
or exceeding that of seawater, slightly saline water — from
1,000 ppm to 3,000 ppm, moderately saline water — from
3,000 ppm to 10,000 ppm,
highly saline water
— from 10,000 ppm to 35,000 ppm, water
containing more than 1,000 parts
per million of dissolved solids of any type, water that contains
significant
amounts of dissolved solids,
water containing dissolved
salts, such as the ocean, (see brine, fresh
water).
Salinity
A quantitative measure of the solute
concentration
dissolved in water, usually measured as parts per thousand or ppt, amount of
dissolved salts in a given volume of water, salt concentration in marine waters,
ranging from zero to about 33 parts per thousand, ppt, in estuaries, does not
have a precise chemical definition, since the proportions of various ions vary
in the different waters of the world.
Salmonid
Fish of the family Salmonidae which includes
trout, salmon and char.
Salt
The product formed when an acid and
a base react.
Saltwater
The water in the ocean or a sea which has
high salinity.
Sample
A small portion of water or other substance
taken at a given place and time for analysis; it is assumed to be representative
of the whole body of water or the rest of the substance within specified statistical
limits (see grab sample, composite sample).
Sanitary
sewer
A system of pipes, conduits and pumps used
to convey sewage from its source generally to a treatment plant
but also to a
ground disposal site, the ocean, irrigation site,
holding lagoon or a stream,
conveys domestic and institutional sewage and blackwater and
industrial wastewater,
as opposed to stormwater.
Saprophyte,
saprophytic
Organisms that do not manufacture their own
food and use the organic matter of dead, decaying
or decayed other organisms as a source of
nutrients for growth.
Saturation
A measure of the proportion of the maximum
amount of a gas, or solid, that can be dissolved in
a liquid, usually water, at the specified
temperature and pressure, alternatively a measure of the
maximum amount of water, or other liquid,
that can be absorbed or held in a porous medium,
the condition of a liquid when it has taken
into solution the maximum possible quantity of a
given substance at a given temperature and
pressure.
Screening
Passing sewage or wastewater through
a coarse
mesh to remove the larger particles, (see
filtration).
Sea
The large, permanent body of salt water
surrounding
the continents and covering most of the
surface of the earth or one of the smaller
landlocked or nearly isolated bodies of salt water.
Secchi
disc
An opaque, black and white disk lowered into
water until the demarcation between the black and
white portions is no longer visible, this
secchi depth is a practical, traditional measurement of
water clarity, and is correlated with turbidity and
the depth of the biological photic zone.
Secondary
sewage treatment
Includes primary sewage treatment and
provides
in addition conditions conducive to the biological oxidation of
the remaining
organic wastes, the second step in most waste treatment
systems, in which bacteria break down the organic parts
of sewage
wastes, usually accomplished by
bringing
the sewage and bacteria together in trickling filters or
in the activated sludge process,
involving the biological process of reducing suspended, colloidal and
dissolved organic matter
in effluent from primary
sewage treatment systems and
generally removing 80 to 95 percent of the Biochemical
oxygen demand,
BOD, and
suspended matter, accomplished
by biological or chemical-physical
methods, removes
floating and settleable solids
and about 90 percent of the suspended
solids,
disinfection is the final stage of secondary
treatment,
(see primary
sewage treatment,
tertiary sewage treatment).
Secondary
wastewater treatment
Includes primary sewage treatment and
provides
in addition conditions conducive to the biological oxidation of
the remaining
organic wastes, the second step in most waste treatment
systems, in which bacteria break down the organic parts
of sewage
wastes, usually accomplished by
bringing
the sewage and bacteria together in trickling filters or
in the activated sludge process,
involving the biological process of reducing suspended, colloidal and
dissolved organic matter
in effluent from primary
sewage treatment systems and
generally removing 80 to 95 percent of the Biochemical
oxygen demand, BOD, and
suspended matter, accomplished
by biological or chemical-physical methods, removes
floating and settleable solids
and about 90 percent of the suspended
solids,
disinfection is the final stage of secondary
treatment, (see tertiary
sewage
treatment).
Sediment
Undissolved soil particles,
sand and minerals washed from the land into aquatic systems
as a
result of natural and human activities, usually
applied to material in suspension in water or
recently deposited from suspension,
all kinds
of deposits from the waters of streams, lakes or
seas.
Sedimentation
A large scale water treatment process where
heavy solids settle to the bottom of the
treatment tank by gravity after flocculation,
the process by which solids suspended in water
are allowed to settle to the bottom of a
basin or container.
Sedimentation
tanks
Wastewater tanks in which floating wastes are
skimmed off and settled solids are removed for
disposal.
Seepage
The slow movement of water through small
cracks, pores and interstices of a material, into or out of a body of surface
or subsurface water, the loss of water by infiltration into the soil from a canal,
ditch, lateral, watercourse, reservoir, storage facility or other body of water,
or from a field.
Separate
sewer
A sewer system that carries only sanitary
sewage or stormwater runoff, when sewers are constructed this way, wastewater
sewage treatment plants do not have to be sized to handle stormwater
flows avoiding
overflows of untreated sewage, (see combined sewer).
Settleable
solids
Suspended solids that will settle when
the
sewage, wastewater or any other water containing
suspended material, is held static for a
period of time, usually about two hours for sewage
treatment.
Settling
Allowing sewage or wastewater to
sit in a
holding basin for a period of time while the larger and heavier
particles settle to
the bottom before the liquid with its solutes and some smaller particulates is
sent for further treatment or directly to the environment.
Sewage
Primarily feces, kitchen waste and
wash water
but usually with other organic and inorganic
materials present.
Sewage
treatment
The complete sewage treatment
process typically
involves a three-phase process, in the primary sewage
treatment process, which
incorporates physical aspects, untreated water is passed through a series of
screens to remove solid wastes, in the secondary
sewage treatment process, typically
involving biological and chemical processes, screened sewage is
then passed a
series of holding and aeration tanks and ponds,
the tertiary
sewage treatment process consists of flocculation basins, clarifiers,
filters and chlorine basins
or ozone or ultraviolet radiation processes.
Sewage
treatment plant
A facility designed to receive the wastewater from
domestic sources and to remove materials that damage water quality and threaten
public health and safety when discharged into receiving streams or bodies of
water, removes greases and fats, solids from human waste and other sources, dissolved
pollutants from human waste and decomposition products, and dangerous microorganisms,
facilities employ a combination of mechanical removal steps and bacterial decomposition
to achieve these results, chlorine is often added to discharge from the plants
to reduce the danger of spreading disease by the release of pathogenic
bacteria.
Sewer
A system of pipes, conduits and pumps used
to convey sewage from its source generally to a
treatment plant but also to a ground disposal
site, the ocean, irrigation site, holding lagoon or
a stream.
Side
channel
A slow moving body of water usually with
two ends open to the main water body.
Site
specific
Limited to the particular site or location
under discussion.
Siltation
The accumulation of sediments transported
by water, the deposition of finely divided soil and
rock particles on the bottom of stream and
river beds and lakes and reservoirs.
Slough
A slow moving body of water usually with
one end open to the main water body.
Sludge
Solid matter that settles to
the bottom of
sedimentation tanks in a sewage treatment plant and
must be disposed of by digestion or other
methods or recycled to the land.
Solute
Any solid material that is dissolved in a
liquid which is the solvent.
Solution
The mixture of dissolved material, the solute and
the liquid solvent.
Solvent
The liquid, usually water, in which solutes are dissolved,
a substance that dissolves other
substances, thus forming a solution.
Sorbed
A general term for the results of the process
of absorption and adsorption, often used to denote
that either or both have occurred.
Sorption
A general term for the process of absorption and adsorption,
often used to denote the
occurrence of both.
Spatial
Of or relating to space.
Spawning
Term used to denote the process where fish,
and other water dwelling organisms, deposit and
fertilize eggs during reproduction.
Specific
conductance
A quantitative
measure of the ability of a water to conduct an electrical current,
related to the type and concentration
of ions in solution and can
be used for approximating the total dissolved
solids concentration in water, one can monitor
electrical conductivity quickly in the field
and estimate total dissolved solids or TDS
without doing any lab tests at all using hand-held
testers, expressed in units of electrical conductance,
Siemens per centimeter at 25 degrees
Celsius, used in ground water monitoring as an
indicator of the presence of ions of chemical
substances that may have been released by a leaking landfill or
other waste storage or disposal
facility.
Specific
gravity
The density of a material related to that of water
whose specific gravity is defined as one.
Sperm
A small motile gamete produced
by the male
organism which contains one haploid set of
chromosomes and swims to the egg to bring
about fertilization.
Standing
crop
The total amount of biological material present
at any given time, (see productivity, biomass).
Stomata
The small pores in the epidermis of plants,
usually in the leaves, through which atmospheric gas
and water exchange takes place and is controlled.
Storm
drain
A drainage system designed for stormwater which
is surface runoff from streets and other impervious surfaces
associated
with urbanization or other anthropogenic activities and distinct
from the sewage system, a sewer that carries
only surface runoff, street wash and snow melt from
the land, storm drains are completely separate from those that
carry domestic and commercial wastewater, (see sanitary
sewers).
Storm
sewer
A drainage system designed for stormwater which
is surface runoff from streets and other impervious surfaces
associated with urbanization or other anthropogenic activities
and distinct from
the sewage system, a sewer that carries only
surface runoff, street wash and snow melt from the land, storm sewers are
completely
separate from those that carry domestic and commercial wastewater,
(see sanitary sewers).
Stormwater
Water which is primarily surface runoff from
streets and other impervious surfaces associated
with urbanization or other anthropogenic activities.
Stormwater
discharge
Precipitation that does not infiltrate into
the ground due to impervious land surfaces, or
evaporate, but instead flows onto
adjacent
land or water areas and/or is routed into storm
drain or sewer systems.
Stratification
Vertical separation of water masses into
layers with different characteristics, dense salt water intruding under fresh
water in a navigation channel can establish salinity stratification, temperature
differences in fresh water can form distinct water layers separated by density,
(see epilimnion, thermocline, hypolimniuon, specific
gravity).
Stream
A relatively small and sometime ephemeral
or seasonal flowing body of fresh water, in
a
defined channel.
Stream
improvement
One or more works, situated in or near a
stream, relating to diversion, storing, measuring,
conserving, conveying, retarding, confining
or using water from the stream.
Sublethal
Involves an effect that does not cause death
of the organism.
Sublimation
The change of state from a solid directly
to a gas, (see evaporation, condensation,
vapourization, transpiration).
Supersaturation
A concentration of a gas
in water above the
equilibrium concentration, this occurs when the
gas enters solution more quickly than it
can be released from the liquid to gas phase as in
extremely high rates of plankton
photosynthesis or in the tail races of dams and under
waterfalls where air is entrained.
Surface
microlayer
The immediate surface of the water only microns thick,
important as the interface for
atmosphere and water equilibrium processes,
the location of highest concentration of
hydrophobic pollutants like
oil, and the
location of floating marine eggs and other biological
larval forms.
Surface
water
Water that flows
in streams and rivers and in
natural lake and ponds, in wetlands
and in reservoirs
constructed by humans but on the surface of the land and not underground,
water on the surface on the
earth, as distinguished from ground water.
Survey
A general overview study of a problem or
area, not too specific or localized.
Suspended
matter
Solids that are not in true solution and
that can be removed by filtration they usually contribute directly to turbidity,
small particles of solid pollutants that resist separation by conventional methods;
operationally greater than 0.45 microns in size; also known as non-filterable
residue, suspended solids or suspended sediment.
Suspended
metals or substances
Metals or substances attached to suspended
solids.
Suspended
sediment
Very fine soil particles that remain in suspension in
water for a considerable period of time due to the upward components of turbulence
and currents, can be removed by filtration and contribute to turbidity.
Suspended
solids
Solids that are not in true solution and
that can be removed by filtration they usually contribute directly to turbidity,
small particles of solid pollutants that resist separation by conventional methods;
operationally greater than 0.45 microns in size; also known as non-filterable
residue, suspended matter or suspended sediment.
Suspension
Large particles are kept from settling out
of a liquid by gravity due to motion or agitation of the
liquid, (see solute, particulate).
Swamp
A wetland that is permanently or seasonally
submerged in shallow water and whose vegetation
is dominated by shrubs and trees.
Synergism
Combined activity such that the effect is
either the additive of separate effects or greater than the
sum of the separate effects.
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T
TDS,
total dissolved solids
A quantitative
measure of the total dissolved organic and inorganic
solids concentration in water,
an indicator test used for water analysis and
also a measure of the mineral content of bottled
water and ground water, one can monitor electrical
conductivity quickly in the field and
estimate total dissolved solids or TDS
without doing any lab tests at all using hand-held testers
since there is a relationship between TDS and
conductivity, sum of all dissolved
materials such as salts,
which are non-filterable and remain following evaporation
of the water, (see specific
conductance).
Temporal
Of, or relating to, time.
Tertiary
sewage treatment
A third step in sewage treatment usually
directed towards greatly increasing the removal efficiency of nutrients, removal
from wastewater of traces of organic chemicals and dissolved solids that remain
after primary sewage treatment and secondary sewage
treatment, selected biological,
physical, and chemical separation processes to remove organic and inorganic substances
that resist conventional treatment practices, consists of flocculation basins,
clarifiers, filters and chlorine basins or ozone and ultraviolet
radiation processes,
the additional treatment of effluent beyond that of primary
and secondary sewage
treatment methods to obtain a very high quality of effluent.
Tertiary
wastewater treatment
A third step in sewage treatment usually
directed towards greatly increasing the removal efficiency of nutrients, removal
from wastewater of traces of organic chemicals and dissolved solids that remain
after primary sewage treatment and secondary sewage
treatment, selected biological,
physical, and chemical separation processes to remove organic and inorganic substances
that resist conventional treatment practices, consists of flocculation basins,
clarifiers, filters and chlorine basins or ozone and ultraviolet
radiation processes,
the additional treatment of effluent beyond that of primary
and secondary sewage
treatment methods to obtain a very high quality of effluent.
Thermal
pollution
An increase in air or water temperature that
harms the climate or ecology of an area, a reduction in water quality caused
by increasing its temperature, often due to disposal of waste heat
from industrial or power generation processes.
Thermocline
The fairly thin zone in a lake that
separates
the upper warmer zone, epilimnion, from the lower
colder zone, hypolimnion.
Tissue
A group of cells of similar structure and
function which perform a specific task in an organism.
TOC,
Total organic carbon
Sum of all organic carbon compounds in water.
Total
dissolved solids, TDS
A quantitative measure of
the total dissolved
organic and inorganic solids concentration in water,
an indicator
test used for
water analysis and also a measure of the mineral content
of bottled water and
ground water, one can monitor electrical conductivity
quickly in the field and estimate
total dissolved solids or TDS
without doing any lab tests at all using hand-held testers
since there is a relationship between TDS and
conductivity, sum of all dissolved
materials such as salts,
which are non-filterable and remain following evaporation
of the water, (see specific
conductance).
Total
metals or substances
A quantitative measure of
the metals or substances
both in the dissolved state and those
sorbed to particulate matter in suspension.
Total
organic carbon, TOC
Sum of all organic carbon compounds in water.
Total
suspended solids, TSS
The total suspended solids in water removable
with a 0.45 micrometer mesh filter.
Toxic
Poisonous or harmful.
Toxicant
An element or compound with a harmful or
lethal effect on the physiology, behaviour,
reproduction or survival of an organism.
Toxicity
A measure of how poisonous a toxin is to
an organism.
Toxicity
test
A bioassay to
determine
the toxicity of a chemical or an effluent using
living organisms, a toxicity test measures the degree of response
of an exposed test organism to a specified concentration of chemical or effluent
sample, living organisms are subjected
to varying dilutions of polluted water or water containing known amounts of presumed
or known toxins or contaminated sediment, mortality, declines in reproductive
rates or behavioral changes indicate a toxic response.
Toxin
A compound or element which is toxic or
poisonous
in common usage. More strictly a toxin is
a natural toxicant made by an organism as
opposed to poisons manufactured by man.
Transpiration
The loss of water into the atmosphere from
living plants, direct transfer of water from the leaves
of living plants to the atmosphere, the passage
of water vapour from a living body through
membranes or pores, process
by which water
that is absorbed by plants, usually through the roots,
is evaporated into the
atmosphere from the plant surface, such as leaf pores or stomata, (see evapotranspiration,
vapourization, evaporation.)
Tributary
A smaller stream which joins a larger stream,
usually, a number of smaller tributaries merge to
form a river.
Trihalomethanes
Chlorinated organic chemicals
which are formed when water containing organic materials is
disinfected with chlorine, these compounds
are toxic.
Trochophore
Free-swimming ciliate larvae of marine
polychaete
worms and other invertebrates.
Trophic
Related to nutrition, referring to one of
the hierarchial levels in the food web or food chain
between the many producers at the bottom
and the few predators at the top.
TSS,
Total suspended solids
The total suspended solids in water removable
with a 0.45 micrometer mesh filter.
Turbid
Coloured or opaque due to matter in suspension,
rivers and lakes may become turbid after a
rainfall due to erosion and
surface runoff containing particulate matter, there
is sufficient
material in suspension that
visibility is
decreased.
Turbidity
The relative lack of clarity
or cloudiness, of water, caused by suspended material, sediments, colored materials
in solution and plankton, correlates, inversely, with available light for photosynthesis,
the quantity of solid particles that are suspended in water and that cause light
rays passing through the water to scatter, turbidity makes the water opaque in
extreme cases, measured in nephelometric turbidity units, NTU.
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U
µ/L,
Micrograms per litre
A concentration unit of
chemical constituents
in solution; the weight of solute per unit
volume
of solvent, usually water,
one thousand micrograms
per litre is equivalent to 1 milligram per
litre, this measure is equivalent to parts
per billion or ppb.
Unsaturated
zone
The zone immediately below the land surface
where the soil pores contain both water and air,
the soil is not totally saturated with
water,
(see aquifer where the pores are saturated with
water).
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V
Vapourization
The change of state from a liquid to a gas,
the change by which any substance is converted from a liquid state and carried
off as a vapor, the process of liquid water becoming water vapor from water surfaces,
land surfaces and snow fields, (see condensation, sublimation, evaporation, transpiration,
evapotranspiration).
Virus
Small non-cellular parasitic organisms
consisting
of little more than DNA, or RNA in a protein
coat, often crystalline, dependent completely
on the cellular machinery of their hosts to complete
their life cycle and reproduce.
Volatilization
The change of state from a liquid to a gas,
the change by which any substance is converted from a liquid state and carried
off as a vapor, the process of liquid water becoming water vapor from water surfaces,
land surfaces and snow fields, volatilization, (see condensation, sublimation,
vapourization, transpiration, evapotranspiration, evaporation).
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W
Waste
Refuse or other unwanted material.
Waste
discharge
A pipe or ditch containing wastewater which
empties into a water course.
Wastewater
Water with waste materials
or pollutants
dissolved in it, containing waste including greywater, blackwater or
water contaminated by contact with waste, including
process-generated and contaminated rainfall
runoff, water that has been used in homes, industries and businesses
that is
not suitable for reuse unless it is treated.
Wastewater
treatment
The complete wastewater treatment
process
typically involves a three-phase process, in the primary wastewater treatment process,
which incorporates physical aspects, untreated water is passed through a series
of screens to remove solid wastes, in the secondary
wastewater treatment process, typically involving biological and chemical
processes, screened wastewater is then passed a series of holding
and aeration tanks and ponds, the tertiary
wastewater treatment process consists of flocculation basins,
clarifiers, filters and chlorine basins or ozone and ultraviolet
radiation processes.
Water
column
The portion of an aquatic or marine environment
extending from the water surface to the bottom
or the surface of the sediment.
Water
cycle
The natural pathway water follows as it changes
between liquid, solid and gaseous states, biogeochemical cycle that moves and
recycles water in various forms through the ecosphere, the circuit of water movement
from the oceans to the atmosphere and to the Earth and back to the atmosphere
through various stages or processes such as precipitation, interception, runoff,
infiltration, percolation, storage, evaporation and transportation, (see hydrologic
cycle).
Water
pollution
Degradation of a body of water by a substance
or condition to such a degree that the water fails
to meet specified standards or cannot be
used for a specific purpose.
Water
quality
A term used to describe the chemical, physical
and biological characteristics of water, usually
in respect to its suitability for a particular
purpose.
Water
quality criteria
Scientifically derived ambient numerical
values for physical, chemical or biological characteristics
of water, biota or
sediment which must not be exceeded to prevent specified detrimental
effects
from occurring to water uses, recommended concentrations,
levels or narrative
statements that should not be exceeded in order to protect the life or health
of organisms.
Water
quality guideline
Numerical concentration or narrative statement
recommended to support and maintain a
designated water use.
Water
quality objective
A water quality criterion or water
quality
guideline adapted to protect the most sensitive
designated water use at
a specific location
with an adequate degree of safety, taking local
circumstances into account.
Water
quality standard
Law or regulation that consists of the designated
use or uses of a waterbody or a segment of a
waterbody and the water quality criteria that
are necessary to protect the use or uses of that
particular waterbody.
Water
table
The level below the surface of the earth
at which the ground becomes saturated with water, the
surface of an unconfined aquifer which
fluctuates
due to seasonal precipitation, the top of the
water surface in the saturated part of an
aquifer.
Water
treatment
A method of cleaning water for a specific
purpose, such as drinking water, irrigation water or
discharge to a stream.
Water
use
Water that is used for a specific
purpose, such as for domestic use, irrigation,
or industrial processing,
associated with human influence on the hydrologic cycle,
includes water withdrawal
from surface water and ground water
sources, water delivery to homes and businesses,
consumptive use of water, water released from
wastewater treatment plants, water
returned to the environment and in-stream uses, such as using
water to produce hydroelectric
power or for navigation.
Watershed
The land area where precipitation runs off
into streams, rivers, lakes and reservoirs, a land feature that can be identified
by tracing a line along the highest elevations between two areas on a map, often
a ridge, large drainage basins contain many smaller drainage sub-basins, land
area drained by a river or stream, the natural hydrologic unit associated with
numerous ecological and physical processes involving water, the most appropriate
geographic unit for management of water quality, (see drainage
basin).
Well
An artificial excavation, by any method,
for the purposes of withdrawing water from the underground aquifer, a bored,
drilled, or driven shaft, or a dug hole whose depth is greater than the largest
surface dimension and whose purpose is to reach underground water supplies or
oil, or to store or bury fluids below ground.
Wetland
Area that is regularly wet or flooded and
has a water table that stands at or above the land surface for at least part
of the year, an area where saturation with water is the dominant influence on
soil parameters and on composition of the plant community, a bog, pond, fen,
estuary, swamp, peatland or marsh.
Whole-effluent
toxicity
The aggregate toxic effect
of an effluent measured directly by a toxicity test.
Withdrawal
Water removed from a ground
water or surface water source for anthropogenic
use.
Worm
Multicellular invertebrate organisms in several
different Phyla which are soft-bodied, elongate and
often parasitic or pathogenic.
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X
Xerophytic
Refers to plants, generally, that are able
to grow under very arid conditions where water is
scarce, physiological and morphological adaptations
to allow growth under arid conditions.
Xeroscaping
Planting vegetation that requires very little
water.
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Y
Yield
A quantitative measure of
how much water
can be pumped from a well, for example, either in absolute units
or as a percentage
of what is actually present in the aquifer, expressed as an
amount per unit of
time or as an instantaneous, continuous withdrawal rate, the
various values will
differ depending upon the recharge rate of the aquifer,
the increase in biomass or productivity over
a season which is not necessarily reflected in the instantaneous
standing crop.
Z
Zooplankton
Primarily microscopic animals which swim
freely in the water column or are carried about by
water currents, many feed on phytoplankton and
are in turn a staple diet of small fish.
Zygote
The diploid union of haploid
sperm and haploid
egg, the start of the next generation.
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This
page was last updated August 1, 2001
