EPA/542/N-92/004 No. 10 October 1992
U.S. Environmental
Protection Agency
Office of Solid Waste
and Emergency
Response
Technology
Innovation Office
The applied technologies journal for Superfund removals and remedial actions and RCRA corrective actions
Natural Biodegradation of Fuel Vapors
in Unsaturated Zone
by Don H. Kampbell, R.S. Kerr Environmental Research Laboratory
olatilization of gasoline and the aer-
obic biodegradation of the vapors is a
major process for removing gasoline
from subsurface material above the wa-
ter table. EPA's Robert S. Kerr Environ-
mental Research Laboratory (RSKERL)
has documented the role of aerobic bio-
degradation of gasoline vapors in the un-
saturated zone above a leak from an
underground storage tank. The field
studies, conducted at the Coast Guard's
Traverse City, Michigan, site, estab-
lished that natural aerobic biodegrada-
tion consumed gasoline vapors that
volatilized from the gasoline spill before
they could reach ground surface. In this
process, oxygen was consumed and car-
bon dioxide was produced. By measur-
ing the concentrations of oxygen, carbon di-
oxide and gasoline vapors, one can deter-
mine when natural biodegradation of fuels is
occurring at a site. Here's what the Traverse
City experience tells us.
At Traverse City, approximately 36,000
gallons of aviation gasoline had spilled
about 20 years ago. The material was
trapped as oily phase residue just above the
water table. Over the 20-year history of the
spill, approximately 39% of the original
mass has volatilized and biodegraded aero-
bically. Gasoline volatilizes and moves up-
ward in the unsaturated zone as a vapor.
Oxygen from the atmosphere moves down-
ward. Microbes in the intermediate area of
the unsaturated zone consume the oxygen
and the gasoline vapors. As a result, oxygen
Gasoline
vapors
Natural
biodegradation
Unsaturated
zone
concentrations de-^
crease with depth,
and oxygen disappears at the water table.
Gasoline vapors are undetected just below
the soil surface and increase with depth.
Thus, the carbon dioxide concentrations
increase with depth as a mirror image of
the decrease of oxygen as the gasoline va-
pors are biodegraded.
Carbon dioxide levels were measured
at both contaminated and uncontaminated
areas of the site. The contaminated area
showed higher carbon dioxide levels,
higher microbial cell counts and a
depletion of oxygen levels when
compared to the uncontaminated area.
For example, at a depth of 3 meters,
carbon dioxide levels comprised 2.2% of
Csee Biodegradation page 2)
Treatability
Study News
I n this issue of Tech
Trends we have an
article on Resource
Conservation and
Recovery Act (RCRA)
opportunities to do
treatability studies.
Don't miss this news
on page 3.
New ATTIC Bioremediation Case Studies
Petroleum/Wood Pres. (3) Petroleum/Solvents (3)
Munitions (4) Munitions/Agrichem. (1)
Coal Tar/Coal (5)
Agrichemicals (7)
Petroleum-Related (77)
Other (9)
Solvents (11)
Wood Preservatives (12)
132 bioremediation case studies provided by Bioremediation Action Committee
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SITE Subjects
Soil Washing
Technology Demo at
Toronto Harbour
by Ten Richardson
Risk Reduction Engineering Laboratory
Petroleum
Hydrocarbons
Soil Washing
Soil
C PA's Superfund Innovative Tech-
nology Evaluation (SITE) program
recently evaluated the Bergmann soil
washing technology in conjunction with
the Toronto Harbour Commissioners
Soil Recycling Demonstration Facility.
The SITE evaluation concluded that this
soil washing technology is effective.
The soil washing unit produces clean
coarse soil fractions and concentrates the
contaminants in a fine slurry so that the
slurry can be treated by other treatment
technologies. The Bergmann technology
has also proved effective in another SITE
demonstration at Saginaw Bay.
The SITE demonstration at Toronto
consisted of a pilot unit that processed
soil from a site that had been used for
metals finishing and as a refinery and
petroleum storage facility. The soil was
contaminated with oil and grease/
petroleum hydrocarbons, naphthalene,
phenanthrene, pyrene, benzo(a)pyrene
and heavy metals. Since the metals
contamination was very low in the
excavated soil, there was no need to
process the soil to remove inorganic
compounds. During the soil washing,
the coarse soil fractions were separated
from the soil by mineral processing
equipment; the separated gravel was
washed to remove and concentrate the
contaminants in a fine slurry. Hydro-
cyclones (similar to centrifuge devices)
were used to separate the contaminated
finer soil from the uncontaminated soil;
and, an attrition scrubber then freed the
organic contaminants from the sand
particles. Additionally, a density
separator removed coal and peat from the
sand fractions. All the contaminants
removed by the processes described
above remained concentrated in the fine
slurry to be treated by additional treat-
ment methods. Initial concentrations of
the contaminants and concentrations in
clean sand (particle size 0.063 ml to 6 ml)
after soil washing were: oil and grease
from 8,233 mg/kg to 2,183 mg/kg; total
recoverable petroleum hydrocarbons
from 2,542 mg/k to 621 mg/kg; naph-
thalene from 11.15 mg/kg to 2.05 mg/kg;
phenanthrene from 6.91 mg/kg to 1.77
mg/kg; pyrene from 5.06 mg/kg to 1.43
mg/kg; and benzo(a)pyrene from 1.91
mg/kg to 0.53 mg/kg.
The soil washing technology is
intended to be used in conjunction with
other techniques to treat the slurry, such
as chemical pretreatment and biological
treatment to remove organics, metals
chelation to remove inorganic compounds
or incineration. This "treatment train"
approach is most useful when sites have
been contaminated as a result of multiple
uses over a period of time. Typical sites
where the process train might be used
include refinery and petroleum storage
facilities, metal processing and metal
recycling sites and manufactured gas and
coal/coke processing and storage sites.
The process is less suited for soils with
undesirable high organic constituents
that result from the inherent mineralogy
of the soils.
For more information on the Toronto
Harbour Commissioners SITE evaluation
of the Bergmann soil washing system
(see Soil Washing page 3)
B/o degradation
(from page 1)
the soil gas in the contaminated area as
compared to 0.03% in the uncontaminated
area; and oxygen levels were 1.6% compared
to 20.8% in the uncontaminated area.
The Coast Guard and RSKERL acci-
dently discovered that biodegradation oc-
curs at a higher rate when grass is planted,
fertilized and watered, than when the top
soil is not managed for turf grass. Two
contaminated areas of the site were studied.
One area had preexisting turf that had been
fertilized. The other area was barren. In
both areas, nine soil gas probe clusters were
placed into the subsurface at 0.5 meter in-
tervals, ranging from a depth of 0.5 meters
to 5 meters (just above the water table).
The subsurface biodegradation of both ar-
eas was compared. Measurements in both
areas showed that natural biodegradation
was occurring. However, biodegradation
in the enhanced turf area occurred at a
higher activity level compared to the barren
am. Microbial cell counts were approxi-
mately two times greater in the fertilized
turfarea.
Natural biodegradation augmented by
soil venting technology and turf enhance-
ment has been chosen to remediate the en-
tire contaminated plume at Traverse City.
For a brief description of in situ biosparg-
ing and bioventing remediation technolo-
gies at Traverse City, see page one of the
June 1992 issue of Tech Trends (EPA Doc-
ument No. EPA/542/N-92/003), "In Situ
Biosparging with Bioventing Cleans Both
Saturated and Unsaturated Zones."
For more information on carbon dioxide
and oxygen as indicators of natural
biodegradation and for more detailed
information on biosparging/bioventing
(referenced in preceding paragraph), call
Don Kampbell at the Robert S. Kerr
Environmental Research Laboratory in
Ada, Oklahoma, at 405-332-8800. Addi-
tionally, for a detailed analysis of the kin-
etics of biodegradation of gasoline vapors
in the unsaturated zone, see "Biodegra-
dation of Hydrocarbon Vapors in the
Unsaturated Zone," by David W. Ostendorf:
and Don H. Kampbell, Water Resources '
Research, Vol. 27, No. 4, April 1991, pp.
453-462.
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RCRA Treatability Study Opportunities
By Michael Forlini, Technology Innovation Office
the Subpart X regulations (52 FR 46961)
discusses acceptable permitting options for a
multi-stage demonstration project, where the
outcome of one stage may radically change
the subsequent stage, as is common in testing
an innovative technology.
Corrective Action. In the Corrective
Action Program, the facility and EPA, in
collaboration with the State, can use a
treatability variance for on-site demonstra-
tions through such mechanisms as permit
modifications at permitted facilities or en-
forcement orders [3008(h) orders for inter-
im status facilities] [40 CFR 268.44(h)].
Treatability variances may be granted to a
facility for those wastes that cannot
achieve the Land Disposal Restrictions'
Best Demonstration Available Technolo-
gies standards. Regions have the authority
to grant a site specific treatability variance
for contaminated soils. These variances
may prove to be extremely useful in im-
plementing alternative treatment tech-
nologies in the RCRA Corrective
Action Program.
's Resource Conservation and Re-
covery Program (RCRA) program pro-
vides different opportunities to do
treatability studies pertaining to treatment
technologies. They range from bench
scale studies to pilot scale treatability
demonstrations. Below is a brief descrip-
tion of some provisions of the regulations
pertaining to treatability studies.
Treatability Studies Exemption
Rule. The Treatability Studies Exemp-
tion Rule (40 CFR 261.4(e)-(f)) applies
to the generation or collection of samples
and standards for treatability studies (as
defined at 40 CFR 261.10) for no more
than one kilogram (kg) of acute hazard-
ous waste, 250 kg of soils, water or de-
bris contaminated with acute hazardous
waste and 1,000 kg of non-acute hazard-
ous waste. EPA's Regional Administra-
tor or, in the case of an authorized State,
the State Director, may grant a request
for additional collection samples. When
operating within the exemption rule,
compliance is not required for the RCRA
regulatory requirements pertaining to
identifying, listing, generating and trans-
porting hazardous waste (40 CFR 261-
263) and the notification requirements of
Section 3010.
Research Development and
Demonstration Permits. RCRA Research
Development and Demonstration (RD&D)
Permits (40 CFR 270.65) can apply to a
pilot scale study. RD&D permits were
created to facilitate the development and
demonstration of treatment technologies.
The RD&D permit provides for the
construction of the facility and its
operation for no longer than one year
unless the permit is renewed. A permit
may not be renewed more than three
times. The one year timeframe pertains
to days of operation.
Subpart X Permits. Subpart X
("Miscellaneous Units" 40 CFR 264.600)
provides another avenue for issuing RCRA
permits to the diverse universe of
innovative technology developers. Subpart
X can be used as a complement to the
RD&D permit program. The preamble to
For a more detailed description of all
the provisions discussed here, we refer
you to the Code of Federal Regulations
(specific CFR citations noted above) and
to the RCRA/Superfund Hotline at 800-
424-9346 or 703-920-9810.
So/7 Washing
(from page 2)
(and the other two "treatment train"
technologies used there in conjunction
with soil washing), call Teri Richardson
at 513-569-7949. For information on the
Saginaw Bay SITE demonstration of the
Bergmann soil washing technology, call
Jack Hubbard at 513-569-7507. An Ap-
plication Analysis Report and a Technical
Evaluation Report that describes the
complete demonstration at the Toronto
Harbour Commissioners Soil Recycling
Demonstration Facility will be available
in the Spring of 1993.
Also, an upcoming issue of Tech
Trends feature a special insert on devel-
opments in soil washing.
New for the Bookshelf
Recent EPA publications are available from the National Center for Environ-
mental Publications and Information (NCEPI). You can order them by
sending a fax request to NCEPI at (513) 891-6685, or sending a mail request
to NCEPI, 11029 Kenwood Road, Building 5, Cincinnati OH 45242. You must
have the document number or the exact title to order a document.
The Technology Innovation Office has recently updated three publications:
Federal Publications on Alternative and Innovative Treatment Technologies
for Corrective Action and Site Remediation, Second Edition.
EPA/542/B-92/001
Accessing Federal Databases for Contaminated Site Cleanup
Technologies, Second Edition.
EPAI542/B-92/002
Synopses of Federal Demonstrations of Innovative Site Remediation
Technologies, Second Edition.
EPA/542/B-92/003
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A *?f*t*
i S IV
Out of the ATTIC
ATTIC Yields Abundant
clearinghouses, databases and
electronic bulletin-boards are not new to
Andy Autry, a Project Scientist for
ENSITE, Inc., responsible for devel-
oping and improving bioremediation
technologies for site restoration.
Dr. Autry routinely checks many EPA
computerized information sources such
as the Clean-Up Information (CLU-IN)
and Office of Research and Development
electronic bulletin boards, and the
Alternative Treatment Technology
Information Center (ATTIC) database. It
was from a bulletin in ATTIC that he
earned about the Vendor Information
System for Innovative Treatment Tech-
nologies (VISIT!) database and was able
o contribute information about his com-
pany's technology for removing petro-
leum hydrocarbons from contaminated
soils. Dr. Autry also uses ATTIC to
download the latest meeting notes from
he Bioremediation Action Committee
BAG) and to get the latest news
bulletins on bioremediation.
He recently accessed ATTIC to check
new information on remediation of soil
contaminated with polyaromatic hydrocar-
bons (PAHs) and phenols. He found 228 re-
ports using those three parameters. He
narrowed that list down by including biore-
mediation in the criteria. This search result-
ed in 24 reports. One, entitled "Slurry-
Phase Bioremediation: Case Studies and
Cost Comparisons," is an overview of avail-
able bioremediation technologies for the
cleanup of contaminated soils, sludges and
water. Slurry-phase bioremediation, a rela-
tively new adaptation to remediation tech-
nology, is described in the abstract; and,
results from selected case studies are pre-
sented. Slurry- phase bioremediation gener-
ally provides more rapid treatment and
requires less area than solid-phase, soil-
heaping or composting biological treatment
processes. Slurry-phase processes are being
used more often at sites where time and
space, rather than cost, are critical.
Another abstract from this search de-
scribes ECOVA Corporation's bioslurry re-
actor which was demonstrated under EPA's
Superfund Innovative Technology Evalua-
tion (SITE) Program and was featured in the
March 1992 issue of Tech Trends (EPA
Information
Document No. EPA/542/N-92/001).
This Reactor can treat highly contaminat-
ed creosote wastes and other concentrat-
ed contaminants that can be aerobically
biodegraded. A second SITE Program
technology-ENSITE, Inc.'s SafeSoil™
Biotreatment System-was included in
the search results.
Dr. Autry also found 132 new case
studies on bioremediation that were re-
cently provided to ATTIC by the BAG.
These reports contain data on bioreme-
diation of 12 different categories of
contaminants from studies that were
conducted by vendors in 3 1 states.
Information on ATTIC is available
from the system operator at 301-670-
6294 or Joyce Perdek of EPA's Risk Re-
duction Engineering Laboratory at
908-321-4380. CLU-IN may be access-
ed online at 301-589-8366 or by voice at
301-589-8368. The ORD electronic bul-
letin board may be accessed at 513-569-
7610 or by voice at 513-569-7345.
VISITT may be ordered by calling 800-
245-4505.
To order additional copies of this or previous issues of Tech Trends, or to be included on the permanent mailing list, send a fax request to the
National Center for Environmental Publications and Information (NCEPI) at 513-891-6685, or send a mail request to NCEPI, 11029 Kenwood
Road, Building 5, Cincinnati OH 45242. Please refer to the document number on the cover of the issue if available.
Tech Trends welcomes readers' comments and contributions. Address correspondence to:
Managing Editor, Tech Trends (OS-110W), U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, DC 20460.
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