United States
                        bnvironmental Protection
 Office of Solid Waste and
 Emergency Response
 OS-420 (WF)
EPA 500-F-92-005
May 1992
ŁEPA            Controlling UST Cleanup  Costs
                        Fact  Sheet 5:   Understanding
                        Contractor Code  Words
Here are a limited number of definitions that are often used
by contractors when they are cleaning up leaking
underground storage tank sites. The definitions focus on
cleanup technologies and terms associated with the
chemical components of gasoline. The list does not
currently include types of site investigation or cleanup

Activated Carbon Adsorption is a widely used method of
cleaning groundwater. In it, particles of carbon are used to
remove chemical compounds from water.

Air Sparging is a method of removing VOCs (see
definition) from groundwater. Compressed air is forced
through a well screen placed in the aquifer causing a
bubbling effect in the groundwater. Contaminants in the
groundwater are forced into the soils above the  aquifer.
These contaminants can then be removed by soil vapor
extraction.  Air sparging can enhance bioremediation.

Air Stripping is a method in which groundwater
contaminated with petroleum is mixed with air. The
mixing process removes the dissolved petroleum from the
water by transferring it into the air. Local air pollution
rules may prohibit using this method.

Aquifer is a water-bearing stratum (layer) of permeable
rock, sand, or gravel.

Bioremediation is the natural process in which
microorganisms (that is, bacteria) break down petroleum
products in the soil. Enhanced bioremediation refers to
the addition of microorganisms or chemicals to speed up
the natural rate of breakdown of petroleum products in the
BTEX is the abbreviation for Benzene, Toluene.
Ethylbenzene, and Xylene, which are all chemical
compounds in gasoline. Site investigations often measure
the amount of these compounds in soil and groundwater; as
such, they are  often called indicator chemicals.

Free Product is the petroleum product that resides in the
spaces between the soil particles or floats on top of the
groundwater and is generally more accessible for removal
or treatment.

Groundwater is the water within the earth that supplies
wells and springs.

Incineration is the process of burning soils or sludges at a
high temperature to destroy contaminants. Air pollution
control devices are usually needed to comply with local or
State regulations.

In-Situ means within place and is often used to refer to the
location of activities (that is, in-situ soil treatment).

Land Farming is a method of removing petroleum
compounds from soils. Contaminated soils are removed
from the ground, spread over a given area, and periodically
tilled to speed up the release of VOCs and breakdown of
the contaminants.

Monitoring Well (Observation Well) is a hollow,
perforated cylinder inserted into a special hole or boring in
the ground for the purpose of obtaining ground-water
                Printed on paper that contains
                at least 50% recycled fiber

 MTBE is the abbreviation for Methyl Tertiary Butyl Ether,
 which is a blending agent added to gasoline.

 Permeability is the quality or the state of being permeable
 (that is, of having pores or openings that permit liquids or
 gases to pass through). Sandy soils are permeable.

 Plume is often used to describe the shape of the
 contaminated area, which is usually elongated. Delineating
 the plume refers to the act of determining the boundaries
 of the plume.

 Recovery Well is a well installed for the purpose of
 pumping contaminated water or free product from an
 aquifer for treatment.  Recovery wells are generally larger
 in diameter than monitoring wells.

 Remediation is the process of cleaning up contamination.

 Site Investigation is the process of confirming that a
 release of petroleum product has occurred; it can involve
 determining the extent of soil and ground-water
 contamination caused by that release.

 Soil Borings are holes drilled in the ground to determine
 soil structure and/or to monitor for the presence of
contaminants  in the soil.

Soil Vapor Extraction draws (with a vacuum pump) fresh
air into the ground and brings toxic contaminants up to the
surface where they can be treated and safely discharged.
 Soil Vapor Survey is a method used to collect and analyze
 volatile petroleum hydrocarbons from subsurface soils."
 Vapor samples are collected from a borehole using a hand
 or vacuum pump and analyzed in the field.

 Soil Venting is a method used to remove gasoline vapors
 from soils without excavation.  This method can be
 performed passively with vents that are open to the
 atmosphere or actively with the use of pressure or vacuum

 TPH is the abbreviation for Total Petroleum Hydrocarbons.
 The level of TPH can be used to determine the amount of
 contamination at a site.

 VOCs, Volatile Organic Compounds, are carbon-
containing compounds that readily vaporize (that is. change
from a liquid to a gas) at normal temperatures and
    Fact Sheet 5 was developed by the Environmental
  Protection Agency's Office of Underground Storage
  Tanks in conjunction with State Fund Administrators.
  It  is one of a series; the  others are:  Hiring a
  Contractor, Negotiating the Contract, Interpreting the
  Bill, and  Managing the Process.  For copies of these
  fact sheets or more information, contact your State
  Fund Administrator for USTs  and/or your  State
  Underground Storage Tank program.