2    BIOLOGICAL TREATMENT OF GROUNDWATER, SOILS,
AND SOIL VAPORS CONTAMINATED WITH
PETROLEUM HYDROCARBONS
Edward G. Galaska, Laboratory Manager
DETOX, Inc.
Dayton, Ohio 45459
George J. Skladany, Manger of Operations
DETOX, Inc.
Dayton, Ohio 45459
Evan K. Nyer, Vice President
Geraghty & Miller Consulting Engineers
Tampa, Florida 33618
INTRODUCTION
Leaking underground storage tanks and pipelines have recently become one of the most widespread
and talked about environmental problems. Across the country, service station gasoline storage tanks
are being tested for leaks and replaced as either necessary or precaution dictates. While the total
number of underground storage tanks is unknown, it is estimated to be in the vicinity of 1.4 million
tanks and, of these tanks, between 10 and 30% are thought to have leaked gasoline into the ground.'
For a leak to be considered a contamination problem, at least 1,000 gallons of gasoline has usually
been spilt. Leaks of up to 270,000 gallons have been reported, and leaks in the range of 20,000 to
50,000 gallons are not uncommon. Most of this gasoline has contaminated the subsurface soils and
groundwater, and in many cases poses a major threat to drinking water supplies, since a single gallon
of gasoline can render 1 million gallons of water unsuitable for consumption.
In most cases, the cleanup operation at petroleum contaminated sites involves the remediation of
groundwater, soils, and air emissions. Typically, heavily contaminated soils are excavated and incinerated or transported to secure landfills. The remediation of contaminated groundwater and air
emissions has focused primarily on air stripping and carbon adsorption technologies. Although both
of these technologies have had varying degrees of success, each has limitations in removing all of the
organic compounds commonly found in petroleum products. In addition, both of these technologies
are considered to be non-destructive, meaning the the contaminants are not destroyed but simply
transferred to another medium (air and/or carbon) requiring further treatment.
Biological methods have had wide application in the remediation of sites contaminated with petroleum hydrocarbons. This technology uses the action of naturally occurring microorganisms to aerobi-
cally metabolize the contaminants present, usually converting the organic compounds into carbon
dioxide, water, and additional bacteria. Above-ground and in-situ biological treatment of contaminated gasoline service stations and oil terminals has been quite successful, since most petroleum
constituents are biodegradable. Further, biological treatment can cost-effectively and efficiently
destroy the specific hydrocarbons present, thus eliminating potential future liability problems associated with other remediation technologies. This chapter will present several case histories describing
the biological treatment of petroleum hydrocarbon contaminated groundwater, soils, and air
emissions.
PROPERTIES OF PETROLEUM HYDROCARBONS
The most common petroleum products contaminating soils and groundwater are gasoline, diesel,
and fuel oils. While these products are generally spoken of as single entities, each is actually a complex
mixture of many organic chemicals. Figure 1 shows some of the major petroleum hydrocarbon
constituents as they would appear in a gas chromatograph separating compounds by increasing the
boiling point. Each of these specific compounds has its own properties and behavior when in contact
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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