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Parameter: A variable, measurable
property whose value is a determinant of the characteristics of a system such
as water. Temperature, pressure, and density are examples of parameters.
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Partial
pressure: That
pressure of a gas in a liquid, which is in equilibrium with the solution. In
a mixture of gases, the partial pressure of any one gas is the total pressure
times the fraction of the gas in the mixture (by volume or number of molecules).
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Particle
size: The sizes
of a particle, determined by the smallest dimension, for instance a diameter.
It is usually expressed in micron measurements.
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Particulate
loading: The
mass of particulates per unit volume of water.
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Parts per
billion (ppb):
Expressed as ppb; a unit
of concentration equivalent to the µg/l.
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Parts per
million (ppm):
The number of "parts" by
weight of a substance per million parts of water. This unit is commonly used
to represent pollutant concentrations. Large concentrations are expressed in
percentages.
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Pasteurization: The elimination
of microorganisms by heat applies for a certain period of time.
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Pathogen: Microorganisms
which can cause disease.
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Pathogenic
microorganisms:
Microorganisms that can
cause disease in other organisms or in humans, animals, and plants.
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Pathogens: Disease-producing
microorganisms.
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Peak flow: In a wastewater
treatment plant, the highest flow expected to be encoutered under any operational
conditions, including periods of high rainfall and prolonged periods of wet
weather.
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Peak/off-peak
rates: Rates
charged in accordance with the most and least popular hours of water use during
the day.
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Per capita
use: The average
amount of water used per person during a standard time period, generally per
day.
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Percent
saturation: The
amount of a substance that is dissolved in a solution compared to the amount
that could be dissolved in it.
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Perched
water table:
Groundwater standing unprotected over a confined zone.
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Percolating
waters: Waters
passing through the ground beneath the Earth's surface without a definite channel.
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Percolation: The movement
of water through the subsurface soil layers, usually continuing downward to
the groundwater or water table reservoirs.
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Perennial
stream: One that
flows all year round. Compare intermittent stream.
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Perfected
water right:
A water right which indicates that the uses anticipated by an applicant, and
made under permit, were made for beneficial use. Usually it is irrevocable unless
voluntarily canceled or forfeited due to several consecutive years of nonuse.
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Permafrost: Perennially frozen
layer in the soil, found in alpine, arctic, and antarctic regions.
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Permeability: The ability of
a water bearing material to transmit water. It is measured by the quantity of
water passing through a unit cross section, in a unit time, under 100 percent
hydraulic gradient.
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Persistence: Refers to the
length of time a compound stays in the environment, once introduced.
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Pesticide: A substance or
mixture of substances intended for preventing, destroying, repelling, or mitigating
any pest. Also, any substance or mixture of substances intended to regulate
plant or leaf growth. Pesticides can accumulate in the food chain and/or contaminate
the environment if misused.
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pH: Numeric value
that describes the intensity of the acid or basic (alkaline) conditions of a
solution. The ph scale is from 0 to 14, with the neutral point at 7.0. Values
lower than 7 indicate the presence of acids and greater than 7.0 the presence
of alkalis (bases). Technically speaking, ph is the logarithm of the reciprocal
(negative log) of the hydrogen ion concentration (hydrogen ion activity) in
moles per liter.
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Phase: A state of matter.
This can be solid, liquid or gaseous.
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Phosphorous: A plant nutrient
that can cause an overabundance of bacteria and algae when high amounts are
present, leading to a depletion of oxygen and fish kills. High levels of phosphorous
in water are usually caused by agricultural runoff or improperly operating wastewater
treatment plants. Also see nitrogen.
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Photosynthesis: The manufacture
by plants of carbohydrates and oxygen from carbon dioxide and water in the presence
of chlorophyll, using sunlight as an energy source.
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Phreatophytes: Plants that send
their roots into or below the capillary zone to use ground water.
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Physical
and chemical treatment:
Processes generally used
in wastewater treatment facilities. Physical processes are for instance filtration.
Chemical treatment can be coagulation, chlorination, or ozon treatment.
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Physical
weathering: Breaking
down of parent rock into bits and pieces by exposure to temperature and changes
and the physical action of moving ice and water, growing roots, and human activities
such as farming and construction. Compare chemical weathering.
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Phytoplankton: Usually microscopic
aquatic plants, sometimes consisting of only one cell.
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Piezometroc
surface: The
imaginary surface to which groundwater rises under hydrostatic pressure in wells
or springs.
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Pit Gauge or US Pit Gage:
a device to measure the depth of corrosion. A pit gauge can take
various forms, in the most basic as a simple lever and pointer or
more accurate units using a dial or digital indicator to provide the
measurement displacement. Pit depth gauge, depth gauge, bridging
bar.
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Pilot tests: The testing of
a cleanup technology under actual site conditions in a laboratory in order to
identify potential problems before implementation.
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Plankton: Tiny plants and
animals that live in water.
-
Plate tectonics: Refers to the
folding and faulting of rock and flow of molten lava involving lithospheric
plates in the earth's crust and upper mantle.
-
Plenum flushes: Rinsing procedure
that discharges deionized water from the rim of a flowing bath to remove contaminants
from the sides and bottom of the bath.
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Plug: Cement, grout,
or other material used to fill and seal a hole drilled for a water well.
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Plume: The area taken
up by contaminant(s) in an aquifer.
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Pluvial: Pertaining to
precipitation.
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POE-treatment: Point-Of-Entry
treatment. Total water treatment at the inlet to an entire building or facility.
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Point source: Source of pollution
that involves discharge of wastes from an identifiable point, such as a smokestack
or sewage treatment plant. Compare nonpoint source.
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Polar substance: A substance that
carries a positive or negative charge, for instance water.
-
Pollutant: A contaminant
at a concentration high enough to endanger the life of organisms.
-
Pollution: Undesireable
change in the physical, chemical, or biological characteristics of the air,
water, or land that can harmfully affect the health, survival, or activities
of human or other living organisms.
-
Polychlorinated
biphenyls (PCBs):
A group of chemicals found
in industrial wastes.
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Pond: A small natural
body of standing fresh water filling a surface depression, usually smaller than
a lake.
-
POP's: Persistent Organic
Pollutants, complex compounds that are very persistent and difficultly biologically
degradable.
-
Pore: An opening in
a membrane or medium that allows water to pass through.
-
Porous: Something which
allows water to pass through it. Compare nonporous.
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Potable
water: Potable
water is considered safe for human consumption and is often referred to as drinking
water. Freshwater that exceeds these chloride and dissolved solids limits is
often referred to as slightly saline, brackish, or nonpotable water and is either
diluted with fresher water or treated through a desalination process to meet
potable-water standards for public supply.
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Potentiation: The ability of
one chemical to increase the effect of another chemical.
-
Potentiometric
surface: The
surface to which water in an aquifer can rise by hydrostatic pressure.
-
POU-treatment: Point-Of-Use
treatment. Water treatment at a limited number of outlets in a building, for
less than the whole building.
-
ppb - parts
per billion:
Number of parts of a chemical found in one billion parts of a solid, liquid,
or gaseous mixture. Equivalent to micrograms per liter (ug/l).
-
ppm - parts
per million:
Number of parts of a chemical found in one million parts of a solid, liquid,
or gaseous mixture. Equivalent to milligrams per liter (mg/l).
-
Precipitate: A solid which
has come out of an aqueous solution. (ex., iron from groundwater precipitates
to a rust colored solid when exposed to air).
-
Precipitation: Water falling,
in a liquid or solid state, from the atmosphere to a land or water surface.
-
Precipitation
process: The
altering of dissolved compounds to insoluble or badly soluble compounds, in
order to be able to remove the compounds by means of filtration.
-
Preservative: A chemical added
to a water sample to keep it stable and prevent compounds in it from changing
to other forms or to prevent microorganism densities from changing prior to
analysis.
-
Pressure
sewers: A system
of pipes in which water, wastewater, or other liquid is pumped to a higher elevation.
-
Pre-treatment: Processes used
to reduce or eliminate wastewater pollutants from before they are discharged.
-
Price at
equilibrium:
Where supply and demand curves intersect. The price at equilibrium is what allocates
resources.
-
Price gouging: Excessive water
rate increases that are unfair to water customers.
-
Pricing/rate
structure: System
used by water utility managers to charge customers for water usage.
-
Primary
wastewater treatment:
First step in wastewater
treatment where screens and sedimentation tanks are used to remove most materials
that float or settle. Primary treatment removes about 30 percent of carbonaceous
biochemical oxygen demand from domestic sewage.
-
Priority
date: The date
of establishment of a water right. It is determined by adjudication of rights
established before the passage of the water code. The rights established by
application have the application date as the date of priority.
-
Process
water: Water
that serves in any level of the manufacturing process of certain products.
-
Product
water: Water
that has passed through a water treatment plant and is ready to be delivered
to consumers.
-
Profundal
zone: A lake's
deep-water region that is not penetrated by sunlight.
-
Protons: Positively charged
building blocks of an atom that are centered in the nucleus.
-
Protozoa: Large microorganisms,
which consume bacteria.
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Public supply: Water withdrawn
by public and private water suppliers and delivered to users. Public suppliers
provide water for a variety of uses, such as domestic, commercial, thermoelectric
power, industrial, and public water use. See also commercial water use, domestic
water use, thermoelectric power water use, industrial water use, and public
water use.
-
Public water
system: A system
that provides piped water for human consumption to at least 15 service connections
or regularly serves 25 individuals.
-
Public water
use: Water supplied
from a public-water supply and used for such purposes as firefighting, street
washing, and municipal parks and swimming pools. See also public supply.
-
Public-supply
deliveries: Water
provided to users through a public-supply distribution system.
-
Public-water
use: Water supplied
from a public-water supply and used for such purposes as firefighting, street
washing, and municipal parks and swimming pools. Public-water use also includes
system water losses (water lost to leakage) and unusable water discharged from
desalination or lime-softening facilities. Also referred to as utility-water
use.
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Puddle: A small pool
of water, usually a few inches in depth and from several inches to several feet
in its greatest dimension.
-
Pump: A device which
moves, compresses, or alters the pressure of a fluid, such as water or air,
being conveyed through a natural or artificial channel.
-
Pumped hydroelectric
storage: Storing
water for future use in generating electricity. Excess electrical energy produced
during a period of low demand is used to pump water up to a reservoir. When
demand is high, the water is released to operate a hydroelectric generator.
-
Purge: To force a gas
through a water sample to liberate volatile chemicals or other gases from the
water so their level can be measured.
-
Purgeable
organics: Volatile
organic chemicals which can be forced out of the water sample with relative
ease through purging.
-
Putrefaction: Biological decomposition
of organic matter; associated with anaerobic conditions.
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Pyrogen: Substance that
is produces by bacteria and it fairly stable. It causes fever in mammals.
