[Welcome Page]
Tell a friend about the Tech Tree!

Home Pages


The follow definitions are used in the description of the cleanup technologies

Skip to Words:
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


pentachlorophenol (PCP)A chemical compound containing carbon, chlorine, oxygen, and hydrogen, is a contaminant used in feed stock material and chemical manufacturing.
perched aquiferAn unconfined aquifer contained by impermeable rock. See definition of aquitard.

The relative ease with which rock, soil, or sediment will transmit a fluid (liquid or gas). High permeability indicates that medium does not significantly retard the flow.

pesticideA substance or mixture of substances intended to prevent or mitigate infestation by, or destroy or repel, any pest.

"Potential of hydrogen." This is a measure of the acidity or alkalinity of a solution. The pH scale ranges from 0 (extremely acidic) to 14 (extremely alkaline). Distilled water and neutral solutions have a pH equal to 7.

phase (physical/chemical)A physically distinct and separable form of matter that may be a single compound. For example, water is stable in three phases: solid (ice), liquid, and vapor. Treatment systems often use phase differences to separate contaminants from water.
phenols One of a group of organic compounds that are byproducts of petroleum refining, tanning, and textile, dye, and resin manufacturing.
phytoremediation The term phyto- means plant. Phytoremediation is a general term for several ways in which plants are used to clean up sites by removing pollutants from soil and water.
phytoremediation A remediation technology that uses plants and trees for contaminated soil and groundwater. See technology description of Phytoremediation.
plume A well defined, usually mobile, area of contamination in groundwater, soil or the air. .
point source A stationary location or fixed facility from which pollutants are discharged or emitted or any single, identifiable discharge point of pollution, such as a pipe, ditch, or smokestack.
polychlorinated biphenyls (PCBs) Any number of biphenyls in which hydrogen atoms on the benzene ring is substituted with chlorine. As a group, they are persistent chemicals in the environment. PCBs were used in high voltage electrical transformers and capacitors because they conducted heat well while being fire resistant and good electrical insulator. Further sale or use of PCBs was banned in
polynuclear aromatic hydrocarbon (PAH) A chemical compound that contains more than one benzene ring. They are commonly found in petroleum fuels, coal products, and tar.
porosity A measure of the total void space in a media. Porosity is not equivalent to permeability, as certain rocks maybe very porous but relatively impermeable.
ppb Part per billion.
ppm Parts per million.
presumptive remedies Preferred technologies identified through historical patterns of remedy selection and EPA's scientific and engineering evaluation of performance data on technology implementation.
pug mill A hand-driven machine which further crushes and blends powder clay.
pump-and-treat A groundwater treatment process that pumps water to the surface and treats it to remove or destroy the contaminant. See technology description of Pump and Treat.

Note: A majority of the terms and definitions are based on the U.S. Environmental Protection Agency's Brownfields Innovative Technology Glossary . Some definitions have been modified/enhanced to support the Tech Tree text.

Skip to Words:
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

This page was last updated OCTOBER 26, 1998
Please E-mail comments/questions about the Tech Tree to: