Aerobic Biodegradation of Oily Wastes
A Field Guidance Book For Federal On-seene Coordinators
Version 1.0, October 2003
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U S. Environmental Protection Agency
Region 6 South Central
Response and Prevention Branch
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EXECUTIVE SUMMARY
This field guidance document was produced specifically as an aid for Federal On-scene
Coordinators (FOSC) in U.S. Environmental Protection Agency (EPA) Region 6. It is intentionally
limited in scope to best serve the requirements of the Region 6 Oil Program. Typically, Oil Program
projects are completed quickly and efficiently and often do not require more than half a year to complete.
Because of the nature of the Oil program, only aerobic land treatment was considered. Ongoing
consultation with state and local officials during the land treatment process is assumed and essential to
success.
The level of detail provided in this field guide may be less than required for each project, but is
sufficient to adequately diagnose technical problems should they occur. The writers of this field guide are
aware that the users come from a variety of backgrounds and possess a wide range of field experience. In
an attempt to develop a tool that may be used easily by both experienced and less-experienced users,
minimum information is provided and an extensive bibliography section including web sites is included.
Once the users have read and become familiar with the field guide, small shaded boxes or tables adjacent
to a "pumpjack" icon help in locating key points throughout the document.
This field guide consists of three parts complemented by appendices. The first part provides
information to help evaluate the nature of the environment where land treatment is considered and a
summary of the existing regulations and policies in Region 6. The second part provides an overview of
the factors to be considered and studied when determining if landfarming is a viable option and also
discusses key points in the process design. The last part focuses on operation issues and provides useful
tools and information for efficient management of aerobic land treatments.
A checklist was also developed to help the FOSC evaluate existing field conditions, evaluate
feasibility of the technology, and monitor bioremediation progress. The items covered by the checklist
are electronically linked to the appropriate section in the document.
The principal author, Ben Banipal, is a registered Professional Engineer who currently serves
EPA Region 6 in the Solid Waste Program. Ben has provided consultation to the Region 6 Oil Program
on many occasions to ensure good land treatment of hydrocarbon-contaminated wastes. Ben produced
this document in conjunction with many experienced FOSCs, with Team Leader Jim Mullins on
temporary detail to the Region 6 Oil Program, and with the Superfund Technical Assessment and
Response Team (START-2) contractor. This document was submitted for peer-review to several experts
(EPA Emergency Response Team (ERT), EPA Headquarters, and University of Tulsa) in the field of
bioremediation.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY 2
CHECKLIST FOR LANDFARMING ASSESSMENT e
PART I 7
INTRODUCTION 7
GLOSSARY 10
SITE CHARACTERIZATION 12
Waste Classification 12
Chemical Analysis for Biodegradation Suitability 12
Soil Evaluation 14
Physical Properties 14
Chemical Properties 15
Biological Properties 16
CRUDE OIL CHEMISTRY 18
SITE-SPECIFIC CLEANUP STANDARD - APPLICABLE FEDERAL AND STATE
REGULATIONS 20
Federal Regulations 20
State Regulations and Policies 21
State Regulations and Policies in the State of Texas 21
State Regulations and Policies in the State of Louisiana 22
State Regulations and Policies in the State of Oklahoma 22
State Regulations and Policies in the State of New Mexico 23
State Regulations and Policies in the State of Arkansas 23
PART II 24
REMEDY SELECTION 24
ECONOMIC/COST BENEFIT ANALYSIS 25
AEROBIC BIODEGRADATION REMEDY SCREENING/ SELECTION STUDIES 26
Biodegradation Treatment Design 27
In Situ Bioremediation Treatment 27
Ex Situ Bioremediation Treatment 28
Land Treatment Unit Site Evaluation and Selection 28
Land Treatment Unit Design and Construction 28
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PART III
30
LAND TREATMENT UNIT OPERATION 30
LTU LOADING RATES 30
BIODEGRADATION TREATMENT TIME 30
CONDUCTING AN EFFECTIVE BIODEGRADATION - MONITORING LTU
PARAMETERS 31
Soil Moisture Content 32
Soil Nutrients 33
Soil pH 34
Effect of Temperature 3 5
Oxygen Infiltration - Tilling 35
LABORATORY METHODS FOR LTU SOIL PARAMETERS TESTING 35
MONITORING HYDROCARBON BIODEGRADATION 36
Baseline Soil Sampling 36
Quality Assurance and Quality Control 36
Interim Soil Sampling 36
Cleanup Level Confirmation Soil Sampling 37
SITE RESTORATION 37
BIBLIOGRAPHY 38
TABLES
TABLE 1-1 Suggested Chemical Analytical Methods for Contaminated Soil Characterization 13
TABLE 1-2 Soil Particle Size Classification 14
TABLE 1-3 Microbial analysis Methods 17
TABLE 1-4 Biodegradation Agents According To The NCP Product Schedule 18
TABLE 1-5 Crude Oil Distillation Fractions 19
TABLE 1-6 Risk assessment for evaluation of oil clean-up levels in New Mexico. 23
TABLE 1-7 Evaluation of clean-up action levels in New Mexico (mg/kg). 23
TABLE 2-1 Estimated cost of various treatment technologies (production only) 25
TABLE 3-1 Initial TPH Loading Rates 30
TABLE 3-2 Summary of Laboratory and Field Treatment Data (Sublette 2001) 31
TABLE 3-3. LTU Soil Characteristics for Effective Bioremediation Treatment 32
TABLE 3-4 Suggested Agricultural Inorganic Fertilizers 34
TABLE 3-5 Field methods to test LTU parameters. 37
TABLE C-l Crude Oils Handled Near Cushing, Oklahoma 46
TABLE C-2 Typical Crude Oils Handled In Region 6 47
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FIGURES
FIGURE 1-1 Evaluation of landfarming as a remediation option for hydrocarbon-contaminated
soils 9
FIGURE 1-2 Schematic representation of the relationship of the various forms of soil moisture
to plants (Sublette, 2001) 15
FIGURE 2-1 Flow Diagram of Tiered Approach (EPA 540/2-91/013A) 26
FIGURE 2-2 Schematic of typical ex situ land treatment unit 29
FIGURE 3-1 Half-life degradation of diesel fuel and various types of crude oils as practiced by
Chevron Texaco Company. (McMillen et al, May 2002) 30
FIGURE 3-2 Factors Requiring Assessment During Biodegradation of Oily Wastes 32
APPENDICES
APPENDIX A - TYPICAL BIODEGRADATION WORK PLAN 40
APPENDIX B - USEFUL CONVERSION FACTORS 42
APPENDIX C - CRUDE OIL CHEMISTRY 44
APPENDIX D - LTU PARAMETER ANALYSIS METHODS 49
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CHECKLIST FOR LANDFARMING ASSESSMENT
Backgroun d in formation
^ Is the source of the release
controlled?
1 1 Yes
~ No
^ Is the site stabilized?
I | Yes
~ No
Establish contamination levels
[TPH]=
[Metals]=
[Other]=
Acceptable contamination
levels (federal and/or state)
S Are levels below
acceptable state levels?
1 1 Yes
~ No
^ Are the following
circumstances present?
1 1 Rocky
land?
1 1 Flood
plains?
~ High
mineral
deposits?
~
[TPH] >8%
^ What type of funding will
be used?
~ CERCLA
~ OPA
1 1 Other
Evaluate soil properties
^ Soil classification
^ SIodc angle
Preferred angle <5%
Measured
%
^ Moisture
Preferred concentration 50-70%
Measured
%
s eH
Preferred 6-8 units
Measured
Units
^ Salinitv
Preferred EC < IdS/m
Measured
dS/m
~ CEC
Preferred 5-25 meq/100 g soil
Measured
Meq/100 g
^ Metals content
Above normal background
I | Yes
~ No
^ Bacterial count
Preferred range 10
gram of soil
to 106 bacteria per
Measured
^ Need for more bugs?
I | Yes
See NCP
~ No
Evaluate oil properties
S API gravity
Measured
API < 20, bioremediation not
favored
^ Sulfur content
Measured
Perform remedy screening
Optimal reduction
weeks
20-60% in 3-6
Reduction
%
Time of study
weeks
Perform remedy selection
Potential problems?
^ Contamination depth
I | <1 foot
In-situ
I | > 1 foot
Ex-situ
Design LTU
1 I Berms?
1 I Liner?
1 I Irrigation?
1 I Other
LTU Temperature
Measured
°C
Temperature <8°C does not favor
bioremediation
TPH Loading
Applied as function of temperature
%
Evaluate 1 TU variables
y Nutrient (C:N:P:K)
Preferred 100:5:1:1
: : :
^ Temperature
Preferred 75-95°F
°F
^ Moisture
Preferred 50-70%
%
•/ pH
Preferred 6-8 units
units
Optimize LTU variables for duration of treatment
Final TPH concentration
Measured
%
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PARTI
INTRODUCTION
The objective of this field guide is to provide guidance to Federal On-scene Coordinators
(FOSC) in selecting and conducting land aerobic biodegradation of oil-contaminated wastes from inland
oil spills, leaking/unplugged oil wells, abandoned oil refinery sites, pipeline ruptures, and/or tank failures.
The United States consumes approximately 1.6 million barrels of oil every day, and roughly 45% of the
United States' crude oil production occurs in EPA Region 6 states (Arkansas, Louisiana, New Mexico,
Oklahoma and Texas). Despite recent technology advances, accidental spills of crude oil and its refined
products occur frequently during extraction, storage, transportation, distribution, and refining process.
Besides these oil handling activities, the number of mature oil fields is growing in Region 6 and so are
abandoned oil wells, which may be either unplugged or plugged improperly. Irrespective of its origin,
when a spill occurs, it has the potential to endanger human health and the environment and may directly
contaminate air, surrounding soil, surface water and groundwater. Because oil spills occur despite all
precautions, we must have countermeasures and remediation options to deal with this challenge in the
most effective, efficient, and economical manner.
Figure 1-1 summarizes some of the steps that must be followed while evaluating and selecting the
appropriate remediation option. The first step when contamination occurs is to ensure that the source is
controlled; if that is the case, mechanical collection can occur and the site may be stabilized. If the source
is still releasing contaminants, an emergency action must be taken prior to the beginning of cleanup
procedures. Once the site is stabilized, the residual soil levels must be established and compared against
federal and state policies/regulations to determine if further cleanup actions are required. In the event that
further remediation is needed, various technologies should be evaluated to determine which is most cost
and time efficient. If bioremediation, or landfarming, is the favored option, a soil and land
assessment/acceptability must be performed. If the area for potential remediation is rocky, has flood
plains, contains high mineral deposits or high concentrations of total petroleum hydrocarbons (TPH) or
metals, landfarming is not the best option and another technology must be selected. Finally, prior to
performing remedy screening, remedy selection, and land treatment unit design, ensure that the proper
funding mechanism is selected. A typical biodegradation workplan can be found in Appendix A.
The scope of this field guide is limited to aerobic biodegradation, also known as landfarming or
land treatment, of oil-contaminated soils. It is arranged in a logical way to facilitate the decision-making
process for selecting biodegradation as a remediation option. It is divided into three parts:
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Part I deals with assessing the site, characterizing the waste, and establishing the origin of waste so that
the appropriate funding mechanism is applied to clean up the spill. Biological, chemical, and physical
classification of waste is described to assess biodegradation feasibility. Finally, state
requirements are reviewed to establish site-specific cleanup levels at the beginning
of the land farming activities.
Part II elaborates on the remedy selection streamlining process along with cost
benefit analysis.
Part III describes the biodegradation implementation and optimization of operations and maintenance of
a land treatment unit (LTU) to achieve cleanup standards in a timely manner. Finally, the restoration
process for the site to pre-spill conditions is presented. Figure 1-1 provides a typical flow diagram of an
Oil Pollution Act biodegradation assessment.
The Principle of Infallibility states: "It is probably not unscientific to suggest that somewhere
or other some organism exists which can, under suitable conditions, oxidize any substance
which is theoretically capable of being oxidized. " E.F. Gale (1952)
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GLOSSARY
Aerobic: In the presence of, or requiring, oxygen.
Anaerobic: Relating to a process that occurs with little or no oxygen present.
API Gravity: The industry standard method of expressing specific gravity of crude oils. Higher API
gravities mean lower specific gravity and lighter oils.
Biodegradation: The breakdown or transformation of a chemical substance or substances by
microorganisms using the substance as a carbon and/or energy source.
Boiling Point: The temperature at which the vapor pressure of a given liquid reaches atmospheric
pressure (and thus starts to boil).
Cation Exchange: The interchange between a cation in solution and another cation in the boundary layer
between the solution and surface of negatively charged material such as clay or organic matter.
Cation Exchange Capacity (CEC): The sum of the exchangeable bases plus total soil acidity at a
specific pH, usually 7.0 or 8.0. When acidity is expressed as salt extractable acidity, the cation exchange
capacity is called the effective cation exchange capacity (ECEC), because this is considered to be the
CEC of the exchanger at the native pH value. It is usually expressed in centimoles of charge per kilogram
of exchanger (cmol/kg) or millimoles of charge per kilogram of exchanger.
CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act. This law
created a tax on the chemical and petroleum industries and provided broad federal authority to respond
directly to releases or threatened releases of hazardous substances that may endanger public health or the
environment.
Clean Water Act: The Clean Water Act establishes the basic structure for regulating discharges of
pollutants into the waters of the United States. It gives EPA the authority to implement pollution control
programs such as setting wastewater standards for industry. The Clean Water Act also continued
requirements to set water quality standards for all contaminants in surface waters and makes it unlawful
for any person to discharge any pollutant from a point source into navigable waters, unless a permit was
obtained under its provisions.
Degradation: The breakdown or transformation of a compound into byproducts and/or end products.
Field Capacity: In situ (field water capacity): The water content, on a mass or volume basis, remaining
in a soil 2 or 3 days after having been wetted with water and after free drainage is negligible.
Heterotrophic bacteria: Bacteria that utilize organic carbon as a source of energy.
Infiltration Rate: The time required for water at a given depth to soak into the ground.
Loading Rate: Amount of material that can be absorbed per volume of soil.
LTU: Land Treatment Unit, physically delimited area where contaminated land is treated to
remove/minimize contaminants and where parameters such as moisture, pH, salinity, temperature and
nutrient content can be controlled.
Osmotic Potential: Expressed as a negative value (or zero), indicates the ability of the soil to dissolve
salts and organic molecules. The reduction of soil water osmotic potential is caused by the presence of
dissolved solutes.
OPA: Oil Pollution Act of 1990. It addresses oil pollution and establishes liability for the discharge and
substantial threat of a discharge of oil to U.S. navigable waters and shorelines.
Oven Dry: The weight of a soil after all water has been removed by heating in an oven.
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Permeability: Capability of the soil to allow water or air movement through it. The quality of the soil
that enables water to move downward through the profile, measured as the number of inches per hour that
water moves downward through the saturated soil.
Metabolism: The sum of all of the enzyme-catalyzed reactions in living cells that transform organic
molecules into simpler compounds used in biosynthesis of cellular components or in extraction of energy
used in cellular processes.
Microorganism: A living organism too small to be seen with the naked eye; includes bacteria, fungi,
protozoans, microscopic algae, and viruses.
NCP: National Contingency Plan (also called the National Oil and Hazardous Substances Pollution
Contingency Plan). Provides a comprehensive system of accident reporting, spill containment, and
cleanup, and established response headquarters (National Response Team and Regional Response
Teams).
Saturation: The maximum amount of solute that can be dissolved or absorbed under given conditions.
TPH: Total Petroleum Hydrocarbons. The total measurable amount of petroleum-based hydrocarbons
present in a medium as determined by gravimetric or chromatographic means.
Wilting Point: The largest water content of a soil at which indicator plants, growing in that soil, wilt and
fail to recover when placed in a humid chamber. Often estimated by the water content at -1.5 MPa soil
matrix potential.
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SITE CHARACTERIZATION
This section describes the basics of site characterization and assessment. For a detailed removal
site assessment, refer to EPA Region 3 Removal Site Assessment Guidebook. After reviewing site
history and conducting a preliminary survey, the extent and type of contamination must be assessed in
detail. The nature of spilled material, its volume, and the extent of contamination specific to the
particular event are some of the variables required to fully conduct the assessment and to evaluate and
choose the most cost-effective removal option.
Waste Classification
A detailed waste classification and a determination of the origin of the waste assist the FOSC in
planning the removal activities and in utilizing the appropriate funding instrument. A thorough "paper
review" and site history must be conducted to establish Oil Pollution Act (OPA) of 1990 or
Comprehensive Environmental Response and Liability Act (CERCLA) authority. Typically, an oil
refinery waste consists of both OPA and CERCLA wastes (oily pits from crude oil,
refined products, tank bottoms, asbestos, corrosives, small laboratory containers,
wastewater treatment wastes, Resource Conservation and Recorvery Act (RCRA)-
listed wastes), and a careful waste classification is required to use appropriate
funding to remediate the site. Reference to Crude Oil and Natural Gas Exploration and Production
Wastes; Exemption from RCRA Subtitle C Regulations, EPA 530-K-95-003, May 1995, may be useful in
evaluating the site and selecting proper funding mechanisms.
Crude oil and petroleum products consist of mixtures of thousands of compounds and are very
complex. To determine appropriate response actions, the properties of these compounds must be
understood. For more information on crude oil properties and components, refer to Appendix C of this
document.
Chemical Analysis for Biodegradation Suitability
Total petroleum hydrocarbons (TPH)-contaminated soils amenable to biodegradation vary in
concentration and waste type. Soils containing high (> 80 g/kg or 8%) TPH concentrations are not
amenable to land treatment. However, concentrations of petroleum product
up to 25% by weight of soil could be treated by mixing with less
contaminated soils to lower the concentrations to desirable ranges. TPH
concentrations less than 8% are readily treatable. The final TPH levels
attainable vary based on waste streams, site conditions, and the component
properties of the waste oil. For example, if the oil is highly weathered and contains very little
biodegradable hydrocarbons remaining, then it is not amenable to bioremediation.
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Long chain and high molecular weight hydrocarbons of generally 20 carbon atoms or higher are
more resistant to biodegradation but still biodegradable. Petroleum products consisting of complex
asphaltenes, polar resins, and tar are not candidates for land treatment.
Representative samples of the land treatment unit (LTU) soil/waste should be collected and
analyzed for, but not necessarily limited to, volatile organic compounds (VOCs), polynuclear aromatic
hydrocarbons (PAH), total petroleum hydrocarbons (TPH), metals, and naturally occurring radioactive
material (NORM). Table 1-1 suggests chemical analytical methods.
TABLE 1-1 Suggested Chemical Analytical Methods for Contaminated Soil Characterization
Analyte
Method
Target Compound
Pro/Con/Remark
TPH
EPA 418.1 (infrared)
EPA 413.1 (gravimetric)
Mineral oil measurement.
Gravimetric oil and grease.
Inexpensive and quick
screening tool. Cannot be used
to identify oil.
Modified EPA SW846 8015B
(GC/FID)
Total petroleum hydrocarbons
& extractable hydrocarbons.
Hydrocarbon quantification,
basic product identification.
Modified EPA SW846 8015B
(GC/FID)
C8 to C40 normal and
branched alkanes.
To determine weathering state
and level of biodegradation.
VOCs
Modified EPA SW846 8260B
(GC/MS)
C5 to C12 analysis, gasoline
additives.
Light product identification and
degree of weathering.
Semi-volatiles
Modified EPA SW846 8270C
(GC/MS)
For PAH only, EPA SW846
8310 (HPLC)
8270C: semi-volatile
compounds including parent
and alkyl-substituted PAHs
8310: PAH
Quantification of all semi-
volatile compounds, fingerprint
information, and long-term
weathering; expensive.
Metals
Total EPA SW846 601 OB
Mercury SW846 7470A
(liquids) and 7471A (solids)
6010B: antimony, arsenic,
barium, beryllium, cadmium,
chromium, cobalt, copper,
lead, lithium, nickel,
selenium, silver, thallium,
vanadium, and zinc.
7470A & 7471A for mercury.
Quantification of all metals
contained in soil; cost depends
on the number of metals that are
analyzed.
TCLP using extraction method
1311
To test metals that may be a
hazard to the environment.
Provides information on
"stability" of metals in soil.
NORM
Direct-reading instrument to
measure effective dose
(Sievert)
Provides assessment of low
levels of radiation.
Direct reading method: quick,
inexpensive, does not identify
the nature of the isotope.
Laboratory analysis to measure
concentration or activity
(Bequerel)
Provides assessment of low
levels of radiation
Laboratory analysis: expensive,
provides accurate quantitative
isotope characterization.
To obtain SW846 methods, go to http://www.epa.gov/epaoswer/hazwaste/test/main.htm
_ - \ Deleted: ..Section Break (Continuous)"]
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Soil Evaluation
Soil is the medium in which treatment will take place; therefore, it is
of utmost importance to evaluate its properties. Soil is heterogeneous in
nature and varies widely in physical, chemical, and biological properties.
The characteristics important in the design and operation of a land treatment
site include the slope, the soil classification (texture and permeability), the
soil moisture content, pH, the cation exchange capacity (CEC), and salinity.
If the initial soil properties are not ideal for the biodegradation of
hydrocarbons, they can be optimized (see Part III).
Physical Properties
A gently sloped terrain can help minimize earthwork, but slopes in excess of 5% are not
recommended for land treatment facilities due to erosion problems and less than ideal surface drainage
and run-off control capabilities. However, physical manipulation of the land may produce the appropriate
slope incline.
A survey should be performed to classify the indigenous soil present on-site. A soil engineer or
scientist may be consulted to perform soil classification. Soil particle analysis allows the identification of
soil type and is inexpensive to conduct. A general soil classification scheme based on the U.S. Standard
Sieve Analysis provides the Unified Soil Classification System (USCS) and is presented in Table 1-2.
TABLE 1-2 Soil Particle Size Classification
Soil Type
U.S. Sieve No.
Particle Size
Coarse-
Grained
Gravely Soil
Retained on No. 4
Larger than 4.75 mm
Sandy Soil
No. 4 through No. 200
From 4.75 to 0.075 mm
Fine-
Grained
Clayey Soil
Passing No. 200
Smaller than 0.075 mm
Silty Soil
Passing No. 200
Smaller than 0.075 mm
If more than 50% of the soil is retained on No. 200 sieve, it is
considered coarse-grained soil; otherwise, it will be fine-grained soil.
Coarse-grained soils permit rapid infiltration of liquids and allow good
aeration; they are considered to be very permeable. However, they may not
control containment of waste and nutrients added to the soil as well as fine-
grained soils, which would be considered impermeable. The oxygen (air)
transfer rate and substrate availability are greater in coarse-grained soils than
in fine-grained soils due to more air pore space and thus favor aerobic
conditions desirable for biodegradation. Coarse-grained soils are also more
desirable since they can be more favorably loaded with hydrocarbons. Fine-
grained soils should be loaded more lightly in a shallower depth and will
generally require more tilling for equivalent performance.
Another important variable that should be assessed during soil characterization is its moisture
content, or the amount of water it can hold. Saturation, field capacity, wilting point, and oven dry are the
four conditions that will help evaluate the irrigation needs of the treated soil. Saturation is undesirable, as
it decreases oxygen availability and limits site access for nutrient application and tilling. About 50 to
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70% of soil field capacity is ideal for microbial activities, and adequate drainage
can help manage that range. Soil field capacity could easily be determined in the
field by saturating the soil, draining it for 24 hours under gravity, then by
weighing and oven drying at 105 C to attain a constant weight.
Weight of drained soil - weight of oven dry soil = weight of water in the soil at field capacity
% of water in soil at field capacity = (weight of water/dry weight of soil) x 100
Infiltration rate should also be assessed because application of a liquid at a rate greater than that
rate will result in flooding and erosion. This variable is also used to calculate the water balance of the
LTU area. Figure 1-2 provides a schematic of soil moisture relationship. At water levels greater than the
field capacity, water may accumulate and result in flooding and erosion. Below the wilting point, the soil
becomes too dry, slowing down microbial activities.
£Wilting Point I^Field Capacity
Hydro
Capillary
Air Space and
Water
Water
Drainage Water
Unavailable Water
Available Water
Gravitational Water
FIGURE 1-2 Schematic representation of the relationship of the various forms of soil
moisture to plants (Sublette, 2001)
Chemical Properties
Soil is a heterogeneous medium and so are its chemical composition and reactivity. The soil may
be acidic or basic, may have high or low nutrients, and may exhibit a different exchange capacity at
different locations in the same area.
The pH of a soil and its cation exchange capacity (CEC) are important
variables to monitor in order to optimize the degradation process. The chemical
reactions that occur in soil proceed at different rates depending upon the pH of the
soil. The pH should be maintained near neutral, around 7.0 units, for optimum nutrient availability but
a pH range between 6 and 8 units is acceptable. Reagents such as lime, aluminum sulfate, and sulfur can
be used to adjust the pH. Caution should be used to avoid "over correction" of pH, and further
consultation may be used to help calculate optimum quantities. The CEC value is an indication of the
capacity of the soil to retain metallic ions (CEC value is usually obtained through laboratory testing) and
is measured in milliequivalents per one hundred grams of dry soil (meq/lOOg). A CEC value greater than
25 is an indication that the soil contains more nutrients and has a high clay content, whereas values less
than 5 indicate a sandy soil with little ion retention. Most metals found in oily wastes are not readily
soluble in water: however, variations of pH may change that property and when treating land where the
soil has a low CEC, care must be taken to manage subsurface of metal ions. With proper pH
management, metals remain immobilized in the treatment zone even with low CEC values.
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Soil salinity results from accumulation of neutral soluble salts (mainly
due to neutral salts of sodium, calcium, magnesium, and potassium) in the upper
soil horizon following capillary movement of the water, which evaporates and
leaves the crystalline form of the salt, which is often indicated by a white crust.
Elevated concentrations of the salts can be lethal to many microorganisms. Assessing the feasibility of
biodegradation in relation to salinity is achieved by measuring electrical conductivity (EC) in dS/m,
which is a general measure of soil salinity. At EC values above 1 dS/m, biological growth is hindered,
and values above 6 dS/m indicate most likely a sterile soil.
Finally, the soil should be analyzed for heavy metal content since a high metal concentration
could be toxic to microbial survival and growth. Metals do not get remediated by native soil bacteria.
Therefore, if the heavy metal concentrations in soil exceed the acceptable residual levels as determined by
federal and state regulations I http://\v\v\v.clcanuplcvcls.com/). bioremediation is not a viable option.
Biological Properties
The biological action in the soil accounts for approximately 80% of waste degradation in soil
(refer to Hazardous Waste Land Treatment, SW-874,1980), the remainder being due to evaporation,
photo-oxidation, and solubilization in water. This is true as long as environmental conditions such as the
presence of oxygen, adequate moisture, moderate temperatures, neutral pH, low to moderate salinity, and
excess nutrients, are present to allow bacteria can to grow exponentially. The impact of these
environmental conditions is discussed in detail in Part III.
The main two approaches of bioremediation include bioaugmentation and
biostimulation. In the first approach, oil-degrading bacteria are added to the
existing bacterial population in the soil to increase the rate of oil consumption.
Biostimulation is the addition of nutrients and optimization of environmental
conditions to improve the biodegradation efficiency of indigenous bacteria. Hydrocarbon degraders are
ubiquitous, so it is seldom if ever appropriate to add an exogenous source of microorganisms to enhance
the native populations. Populations of hydrocarbon degraders exposed to hydrocarbons increase rapidly
when given adequate aeration, moisture, favorable pH, and excess nutrients . This has been demonstrated
repeatedly in the literature.
Generally, hydrocarbon-degrading bacteria are found in the range of 105 to 106 bacteria per gram
of soil under no oil spill conditions, and when exposed to crude oil, that number increases to 106 to 10s
per gram of soil. A detailed description of soil microbiology is beyond the scope of this field guide, but
typically, one gram of rich agricultural soil contains 2.5xl09 bacteria (heterotrophic count), 5xl05 fungi,
5xl04 algae, and 3xl04 protozoa. (Sublette, 2001) Soil samples should be analyzed for enumeration of
both heterotrophic and hydrocarbon-utilizing bacteria population to verify population densities. The
population of microorganisms could be assessed in soil by plate count, most probable number technique,
phospholipid fatty acid (PLFA) analysis, or denaturing gradient gel electrophoresis (DGGE). (Zhu et al,
16
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2001) The following table provides a summary of these methods. It should be noted that there is no
single species of bacteria that can metabolize all the components of crude oil.
TABLE 1-3 Microbial analysis Methods
Plate Count
Most Probable
Number
Phospholipids F atty
Acid (PLFA) Analysis
Denaturing Gradient Gel
Electrophoresis (DGGE)
Provides a count of
colonies formed on
specific solid media.
Uses liquid media and
hydrocarbons as the
carbon souce to
evaluate microbial
growth.
Can provide a
quantitative assessment
of viable biomass,
community
composition, and
nutritional stature.
Identifies species
distribution.
Inexpensive.
Simple field method,
slightly more labor
intensive and time
consuming.
Requires specialized
knowledge and
expensive
instrumentation.
Requires specialized
knowledge and expensive
instrumentation.
Does not differentiate
between types of
bacteria.
Specific to
hydrocarbon-
metabolizing bacteria.
Can be used to analyze
culture-independent
bacteria but does not
identify species.
Species-specific, can
provide fingerprint of
bacterial community.
Although published results indicate that commercial bioaugmentation products do not enhance
biodegradation rates nor improve the degree of hydrocarbon remediation, there are rare circumstances
when bioaugmentation may be warranted. If the environmental conditions are not favorable to
indigenous bacteria, such as, for example, in brine soils where the salinity is too high to support normal
bacterial populations, a commercial culture highly tolerant of hostile salty environments and able to
degrade hydrocarbons may be added.
EPA has compiled a list of bioremediation agents as part of the NCP product schedule, which is
required by the CWA, the OPA and the NCP (EPA 2000). A current list of the agents in the NCP
schedule is provided in Table 1-4. A product can be listed only when its safety and effectiveness have
been demonstrated under the conditions of a test protocol developed by EPA. (NETAC, 1993) However,
listing does not mean that the product is recommended or Government-certified for use on an oil spill.
The EPA efficacy test protocol uses laboratory shake flasks to compare the degradation of artificially
weathered crude oil in natural seawater with and without a bioremediation product. Biodegradation is
proven with a full gas chromatography/mass spectrometry (GC/MS) analysis that shows the product
degrades both alkanes and aromatics.
17
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TABLE 1-4 Biodegradation Agents According To The NCP Product Schedule
(Adopted from U.S. EPA 2000, June 2003)
http://www.epa.gov/oilspill/ncp/
TYPE
NAME OF TRADEMARK
MANUFACTURER
BIOLOGICAL ADDITIVES
(Microbial Culture or
Enzyme Additives)
BET BIOPETRO
BioEnviro Tech
Tomball, TX
MICRO-BLAZE
Verde Environmental, Inc.
Houston, TX
OPPENHEIMER FORMULA
Oppenheimer Biotechnology, Inc.
Austin, TX
PRISTINE SEA II
Marine System
Baton Rouge, LA
STEP ONE (aka B&S Industrial)
B&S Research, Inc.
Embarrass, MN
SYSTEM E.T.20
Quantum Environmental Technology, Inc.
La Jolla, CA
WMI-2000
WMI International, Inc.
Houston, TX
NUTRIENT ADDITIVES
INIPOL EAP 22 (Oleophilic)
Societe, CECA S.A.
France
LAND AND SEA RESTORATION
Land and Sea Restoration LLC
San Antonio, TX
BILGEPRO (S-200)
International Environmental Products LLC
Conshohocken, PA
OIL SPILL EATER II
Oil Spill Eater International, Corporation
Dallas, TX
VB591™ WATER
VB997TM SOIL, AND BINUTRIX
(partially encapsulated and oleophilic)
BioNutra Tech, Inc.,
Houston, TX
CRUDE OIL CHEMISTRY
Crude oil is a complex mixture of mainly organic compounds comprised from 1 to 60 carbon
atoms and hydrogen atoms (approximately 85% carbon, 15% hydrogen). The composition of crude oil
depends upon the type of oil formation, the location, and the underground conditions where it is found.
The majority of crude oil contains high amounts of hydrocarbons compared to the non-hydrocarbon
fraction (90%: 10% ratio). While carbon and hydrogen are the main elements of crude oil, sulfur (0-5%),
nitrogen (0-1%) and oxygen (0-5%) are other important minor constituents. Typically, crude oil also
18
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contains a wide variety of trace metals like nickel, iron, aluminum, vanadium, and copper. Heavy metals
commonly found in land-treated refinery wastes in concentrations greater than 10 parts per million (ppm)
include chromium, copper, lead, nickel, and zinc. Note that high metal concentrations may "disallow"
use of OPA funds for cleanup efforts.
Generally, crude oil is distilled to separate different fractions of hydrocarbons according to their
boiling point ranges. Table 1-5 presents typical crude oil fractions based on approximate carbon chain
and boiling points.
TABLE 1-5 Crude Oil Distillation Fractions
Fraction Name
Appropriate Carbon
Number Range
Boiling Range
(°F)
Gas (Butane, LPG, Propane, Methane and Lighter)
CI -C4
<90
Gasoline (Auto Gasoline and Aviation Fuel)
C5 -C12
90 - 220
Naphtha and Jet Fuels (Jet Fuel, Solvents)
Cll -C13
220- 315
Kerosene and Jet Fuels (No. 1 Fuel Oil)
C10-C13
315-450
Light Gas Oil (Diesel Fuel, No. 2 Fuel Oil, Home-heating Oil)
C10-C20
450 - 650
Heavy Gas Oil (No. 4 & 5 Fuel Oil, Lubricating Oil)
C19-C40
650 - 800
Residuals - Residual Oil (Bunker C Oil, Waxes, Asphalt, Coke)
> C40
>800
Typically, fractions that have the lowest boiling point contain
shorter-chain hydrocarbons and will biodegrade quicker and more
efficiently. Other factors that influence the ability of crude oil to
biodegrade are its API gravity and sulfur content. An elevated value
of API gravity indicates that the oil contains a high concentration of
short-chain hydrocarbons; thus it has a lower boiling point and biodegrades faster. As a rule of thumb,
oils with an API gravity greater than 30 will biodegrade quite readily, and oils with an API gravity less
than 20 will be very difficult to biodegrade and are probably not suitable for landfarming. API gravity
is also important to know because it can be used to predict the
biodegradability of the oil according to the following empirical
formula: (2.24 x API gravity) - 19.28 = max % Oil & Grease
biodegraded (McMillen, Oct 2002).
Oils that have high sulfur content are considered to be sour as opposed to oils that have a low
sulfur content, which are considered sweet. The API gravity and sulfur content found in various crude
oils handled in this region can be found in Appendix C.
19
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Oil undergoes several physical, chemical, and biological changes when introduced in the
environment. This change is often referred to as weathering and includes several processes: evaporation
of volatiles, dissolution in water, photo-oxidation by sunlight, and of course, biological degradation. All
these processes favor the weathering of oil by degrading the short-chain hydrocarbons. Therefore, oils
that have sustained more weathering will be more difficult to bioremediate.
Another and, by far, the best means to characterize oils is to perform a gas chromatographic/mass
spectrometric analysis of the oil. The gas chromatograph separates each constituent of the oil and forms a
fingerprint spectrum, whereas, the mass spectrometer identifies each constituent. The fingerprint can be
used to positively identify the type of oil present and can also provide an indication on the degree of
weathering of the oil. The comparison between the fingerprint spectrum of a fresh crude oil and
weathered oil is found in Appendix C.
SITE-SPECIFIC CLEANUP STANDARD - APPLICABLE
FEDERAL AND STATE REGULATIONS
The legislation at both federal and state level may affect the use of biodegradation technology.
Existing regulations and policies that govern the use of biodegradation agents in response to spills in EPA
Region 6 are summarized in the following sections.
Federal Regulations
Subpart J (40 CFR Part 300.910) of the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP) governs the use of dispersants and other chemical and biological agents that
may be used in responding to oil spills. EPA prepares and maintains the schedule, known as the NCP
Product Schedule, which is updated as needed. However, the listing of a product does not constitute
Government approval or endorsement of the product.
Specifically the Subpart:
• Restricts the use of chemicals and biological agents to those listed on the NCP Product
Schedule (see Table 1-4).
• Specifies technical product information that must be submitted to EPA for an agent to be
added to the Schedule.
• Establishes conditions for obtaining authorization to use chemical or biological agents in a
response action.
The Schedule is available on the Oil Program website at http://www.epa.gov/oilspill/ncp/
The FOSC, with concurrence of the EPA to the RRT as well as the RRT representative from the
state with jurisdiction over the waters threatened by the spill, may authorize the use of any agent listed on
the NCP Product Schedule. In addition, when practical, the FOSC should consult with the U.S.
20
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Department of Commerce (DOC) and U.S. Department of Interior (DOI) representatives to the RRT
before making a decision to bioremediate a spill. The use of particular products under certain
circumstances is approved in advance by the state, DOC, and DOI representatives to the RRT; if such pre-
approval is specified in the Regional Contingency Plan, the FOSC may authorize bioremediation without
consulting the RRT.
State Regulations and Policies
Although there are no state regulations that specifically address
the use of bioremediation for spill response, the American Petroleum
Association proposed a total petroleum hydrocarbon (TPH) concentration
of 10,000 mg/kg as a criterion for cleaning up a site. A recent study has
found that level to be protective of human health. (API 2001). However,
some states have established guidelines and policies that use a risk-based,
site-specific approach (using parameters such as groundwater depth and
proximity to residential areas) to determine adequate clean up levels.
Regulations and Polities in the State of Texas
There are no state regulations that prescribe the use of bioremediation and specify cleanup levels.
However, there are legislative provisions prohibiting any activities that cause pollution of the State waters
{Texas Water Code, Section 26.121). The Texas state agencies responsible for environmental regulations
include the Texas Department of Health, Railroad Commission of Texas, Texas Commission on
Environmental Quality (TCEQ), Texas Park and Wildlife Department, and General Land Office. These
State agencies generally encourage the use of bioremediation for spill response when appropriate and
when a physical means of cleanup are not feasible.
The TCEQ, which has jurisdiction over hazardous substances and inland oil spills, encourages
bioremediation and reviews proposals to use this technology on a case-by-case basis. Under the authority
of Texas Water Code, Section 26.264(e), the TCEQ is compiling a list of experts who can provide help
during spill responses in Texas. Cleanup standards are not established for TPH due to lack of toxicity
values. However, concentrations of constituents of concern, for which toxicity values have been
established (e.g. benzene), should be determined and compared to health-based standards.
http://www.tnrcc.state.tx.us/enforcement/emergencv rcsponsc.html
The General Land Office (GLO), which has jurisdiction over marine oil spills in the State of
Texas, has no specific policies regarding bioremediation for spill response. The Texas Oil Spill
Prevention and Response Act of 1991 authorizes the Oil Spill Oversight Council to provide advice to the
GLO on bioremediation-related issues.
21
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The Railroad Commission of Texas (RRC) has spill response authority for spills and discharges
from all activities associated with the exploration, development, or production, including storage and
transportation, of oil, gas, and geothermal resources. The RRC, under Texas Administrative Code, Title
16, Part 1, Chapter3, rule 3.91 provides guidelines on remediation of soil.
• A final cleanup level of 1.0% by weight TPH must be achieved as soon as technically
feasible, but no later than one year after the spill incident. The operator may select any
technically sound method that achieves the final result.
* If on-site bioremediation or enhanced bioremediation is chosen as the remediation method,
the soil to be bioremediated must be mixed with ambient or other soil to achieve a uniform
mixture that is no more than 18 inches in depth and that contains no more than 5.0% by
weight TPH (50 g/kg).
Furthermore, the NCP states that prior to using any chemical or biological agents to combat oil
spills in water, the FOSC must obtain concurrence with TCEQ or GLO, unless the immediate use is
necessary to prevent or substantially reduce a hazard to human life.
Regulations and. Policies in the State of Louisiana
The State of Louisiana has no regulations specifically restricting the use of bioremediation.
However, Louisiana does require that selected oil spill methods be approved by the FOSC with
concurrence from the Office of the Louisiana Oil Spill Coordinator. The Louisianan Oil Spill Prevention
and Response Act of 1991 authorizes the Interagency Council to provide advice to the Office on
bioremediation-related issues. Also, for all spills in the state, physical removal shall be the initial means
of cleanup; bioremediation shall be considered only when physical means of cleanup have been exhausted
or deemed unfeasible.
According to Title 43, Part XIX, Subpart 1 (Statewide Order 29B), Chapter 3, Section 313D, soil
at exploration and production sites may be left without further treatment if it does not exceed the
following criteria: pH between 6-9, metal concentrations within acceptable limits, and oil and grease
content of soil below 1% (dry weight)._Additional parameters apply in elevated, freshwater wetland
areas.
Regulations and Policies in the State of Oklahoma
Currently, there are no regulations for the bioremediation of oil-contaminated soil in the State of
Oklahoma; however, some guidelines may be followed to aid in assessing the cleanup levels that should
be achieved. Title 165 of the Oklahoma Corporation Commission, Chapter 29, discusses the remediation
of petroleum storage tank sites and establishes that levels exceeding the following concentrations in
native soils may require further treatment: benzene, 0.5 mg/kg; toluene 40 mg/kg; ethylbenzene 15
mg/kg; xylene, 200 mg/kg; and TPH, 50 mg/kg.
-------
Regulations and Policies In the State of New Mexico
Although there are no regulations for cleanup levels following bioremediation in the State of New
Mexico, the Oil Conservation Division makes some recommendations about these levels. It uses a
scoring system to evaluate the potential risk to public health, fresh waters, and the environment. The sum
of the individual scores is added in order to determine the degree of remediation that should be achieved
at a specific site. The tables below help assess the cleanup levels for benzene, BTEX, and TPH.
TABLE 1-6 Risk assessment for evaluation of oil clean-up levels in New Mexico.
Criteria
Score
Depth of ground water
<50 feet
20
50-99 feet
10
>100 feet
0
<1000 feet from water source
Yes
20
<200 feet from private domestic
water source
No
10
Distance to surface water body
<200 horizontal feet
20
200-1000 horizontal feet
10
>1000 horizontal feet
0
TABLE 1-7 Evaluation of clean-up action levels in New Mexico (mg/kg).
Score
>19
10-19
0-9
Benzene
10
10
10
BTEX
50
50
50
TPH
100
1000
5000
Regulations and Policies in the State of Arkansas
The Arkansas Hazardous Waste Division does not have specific cleanup levels and follows EPA
Region 6 Human Health Medium-Specific Screening Levels ('www.epa.gov/Region6/6pd/rcra c/pd-
n/screen.htm'l for screening purposes. The majority of the sites are cleaned up to site-specific levels
using a risk-based approach.
23
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PART II
REMEDY SELECTION
Several options are available to clean up soil contaminated with oily wastes. The EPA guidance
document How to Evaluate Alternative Cleanup Technologies for Underground Storage Tank Sites
http://www.epa.gov/swerust 1 /pubs/tums.htm may be useful to the reader as it examines ten alternative
remediation technologies.
A very important factor in the selection of the adequate
remediation technology is cost. Not only does the actual treatment
cost need to be evaluated, the added cost of preparatory work such
as laboratory scale treatability studies or pilot-scale evaluations
should be included. That preparatory work is essential to properly
determine if the selected treatment will permanently and
significantly reduce the concentration of contaminants in soil prior
to designing and constructing the actual land treatment unit. Landfarming is not a simple chemical
degradation process, it also involves biochemical processes and its applicability must be evaluated prior
to conducting large scale operations in order to adjust the variables and optimize the efficiency in a
minimum amount of time.
Landfarming is recommended when large land areas are available, the groundwater is deep or an
impermeable barrier can be constructed, starting oil concentrations are less than 5%, and a long treatment
time is not an issue (McMillen, May 2002.)
24
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ECONOMIC/COST BENEFIT ANALYSIS
TABLE 2-1 Estimated cost of various treatment technologies (production only)
Treatment technology
Cost per yd3($)
Washing
165-250
Landfill disposal
65-525
Thermal incineration
40-900
Solvent extraction
85-375
Encapsulation
400-650
Incineration
325-1000
Natural bioremediation
3-50
Land treatment
40-90
Ex Situ treatment
130
Land treatment (bioremediation) with minimal leachate
control
40-80
Land treatment (bioremediation) with extensive leachate
control
135-270
Bioremediation (using microbe addition)
17-165
One of the factors that must be considered prior to selecting bioremediation as an alternative for
the treatment of contaminated soil is the cost. Although the cost per ton or cubic meter for
bioremediation is often less than that of other technologies (see Table 2-1), the cost of laboratory studies
and pilot tests must be included when estimating the total cost of the remediation. Treating larger
amounts of soil using bioremediation will result in more economy since the cost of the studies and tests
can be amortized over a larger overall cost for the project. Estimated costs for laboratory studies are
between $25,000 and $50,000, and can vary from $100,000 to $500,000 for pilot tests or field studies.
The costs listed above are approximations and several factors can contribute to lowering the cost
per unit. The proximity of materials needed to perform the remediation will decrease transportation costs,
and if the labor for tilling and monitoring costs are amortized over a larger area, the unit cost will also
decrease.
25
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AEROBIC BIODEGRADATION REMEDY SCREENING/
SELECTION STUDIES
Site
Characterization
Technology
Screening
T
Technology
Potentially
Viable?
Treatability
Studies
Needed?
Screen
Management
Decision Factors
Technology
Demonstrated
for
Contaminant
Matrix?
No
Remedy
Screening
Studies
Technology
Feasible?
Screen
Meet
Performance
Goals?
Screen
~l Out
Remedy
Selection
Studies
Meet
Performance
Goals?
Detailed
Analysis of
Alternatives
Remedy
Design
Studies
FIGURE 2-1 Flow Diagram of Tiered Approach (EPA 540/2-91/013A)
Remedy screening is the first level of testing, usually conducted to establish the validity of a
technology to treat a waste. It is inexpensive and only requires a short period (average 4 to 6 weeks) to
identify operating standards for investigations. It is a preliminary indication of a technology to meet
performance goals. Typically, test reactors are used to conduct this study with different pre-determined
parameter controls. The results of various test reactors are compared with a reactor with inhibited control,
26
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which is treated with sterilization agents. Generally, a reduction of 20 to 60% (corrected for non-
biological losses) in a period of 3 to 6 weeks is considered successful. This remedy screening evaluation
should provide indications that the degradation is due to biological processes and not to abiotic processes
such as volatilization and photodecomposition, and provide design information required for the next level
of testing.
Remedy selection is the second level of testing. This phase
generally requires several weeks to months to complete and the study
provides data used to verify that the technology is likely to meet the
cleanup goals. The test simulates field conditions and identifies
potential problems that may be encountered during the full-scale
project. Detailed procedures of these studies can be found in EPA
guidance documents EPA/540/2-91/013A and EPA/540/R-93/519a. The studies are typically conducted
for large projects and when TPH concentrations are very high, and there is potential for presence of heavy
metals. A poor soil structure like clayey soils may warrant this type of study. A typical tiered approach
to remedy screening, selection, and design is depicted in the flow diagram illustrated in Figure 2-1.
Biodegradation Treatment Design
In-Situ Bioremediation Treatment
If the contaminated soil medium is generally less than 12 inches
and there is remote concern for groundwater contamination due to
potential off-site migration, in-situ biodegradation should be considered
to minimize material handling and to reduce costs. Perimeter berms
should be constructed to control stormwater run-on and runoff. In
addition, social and economical restraints and current land use must be
evaluated before initiating the project to avoid any future public opposition. The FOSC must confer with
the state before initiating an in-situ bioremediation project.
27
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Ex-Situ Bioremediation Treatment
Land Treatment Unit Site Evaluation and Selection
When the contaminated soil volume is very large or hydrocarbons
have penetrated deeply into soils and waste cannot be treated in situ, ex-
situ bioremediation should be considered. The land treatment unit (LTU)
provides a platform where soil conditions (pH, nutrient, moisture, and
tilling) can be optimized to promote microbial activities. Before selecting
an LTU site, many factors such as local hydrology, geology, existing
topography, climate, and prevailing winds must be considered because a single overriding factor can
make a site unsuitable for land farming. A brief discussion of these parameters is provided in the
following paragraph; however, for a detailed consultation refer to Hazardous Waste Land Treatment, SW-
874, September 1980.
Before selecting a site, indigenous soil, surface water, and groundwater hydrology should be
evaluated. Highly permeable soils present high potential for groundwater contamination. Groundwater
hydrology evaluation allows one to position monitoring wells up- and down-gradient of the LTU (if
required by the regulations). In addition, a geological assessment will aid in proper design and operation
management. Although climate has a great influence on the waste treatment process, there is no direct
control on this factor, but a historical study of local climate may help determine LTU loading and
estimated treatment times during hot and cold cycles. Prevailing winds dictate the location of the LTU
with reference to nearby population.
Land Treatment Unit Design and Construction
A properly engineered LTU can compensate for many limiting factors, which were discussed in
the previous section. Based on site-specific conditions and state requirements, a LTU could be designed
with a liner (synthetic or clay) to prevent any off-site migration of leachate generated during the waste
treatment phase. Perimeter side berms should be constructed to control stormwater surface run-on and
runoff. Figure 2-2 illustrates a schematic of ex-situ land treatment unit. An irrigation system may be
installed, depending on local climate, to maintain the soil moisture content in desirable range. A leachate
collection coupled with irrigation system could assist in recirculation of leachate generated from the LTU,
including any storm water run-on, and eliminate the off-site disposal.
-------
BI OA LJG MENTATION
(IF RFQUIRED)
EIRE WATER POND
WHEEL LINE
IRRIGATION SYSTEM
LEACHATL TO
WASTEWATER TREATMENT
FIGURE 2-2 Schematic of typical ex situ land treatment unit
29
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TABLE 3-2 Summary of Laboratory and Field Treatment Data (Sublette 2001)
Initial
Final
Hydrocarbon
Concentration
Concentration
Average Rate
T 1/2
Type
(mg/kg)
(mg/kg)
(mg/kg/day)
(Days)
Diesel Fuel
100.000
42.000
518
50
No. 6 Diesel
60.000
24.000
400
68
Diesel Fuel
4.500
270
87
12
Diesel Fuel
1.350
100
10
70
Diesel Fuel
1.200
100
40
8
Crude Oil
15,000
6.750
56
122
Oils (Refinery)
12.980
1.273
50
71
Heaw Oil
7.900
3.000
58
60
Crude Residuals
6.000
1.000
65
38
Studies by Chevron Texaco demonstrate that there is a correlation
between API gravity, Oil and Grease, and TPH percent loss that can be
achieved with bioremediation over a period of time. Oils with higher
API gravity, and thus with a higher content of light hydrocarbons, exhibit
a higher percent loss of Oil and Grease and TPH.
CONDUCTING AN EFFECTIVE BIOREMEDIATION -
MONITORING LTU VARIABLES
Soil moisture, pH, nutrients, oxygen transfer, presence of metals and toxics, and salinity are the
utmost controlling factors, that must be monitored and can be optimized to achieve time-efficient
biodegradation rates at a given site. Another important factor is the climate, but it is beyond the control
of the responder. Figure 3-2 demonstrates many essentials to conducting an effective bioremediation of
oil wastes. Desirable soil parameters ranges that should be maintained to conduct a time-efficient
bioremediation in the land treatment unit are as follows:
moisture content (% field capacity) 50-70%, pH 6-8, temperature
75-95°F, and nutrient ratio (C:N:P:K) 100:5:1:1. 3-3 provides a
desirable optimal soil parameter. A detailed discussion on each
factor is provided in the following sections of this part.
31
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Indigenous
bacteria
Commercial bugs
Moisture
Irrigation
Toxicity
Heavy Metals
Nutrients
Fertilizers
pH of soil
Biodegradation
Tilling
Air Exchange
Metabolite
removal
Temperature
Weather
FIGURE 3-2 Factors Requiring Assessment During Biodegradation of Oily Wastes
Soil Moisture Content
Soil moisture maintenance at ultimate levels is very important and is generally the most neglected
area in land farming operations. Too much water or too little water can be detrimental to an aerobic
bioremediation operation. Saturation will inhibit oxygen infiltration, and dry conditions will slow down
the microbial activity or even stop the biodegradation process if a wilting point is reached. A desirable
range is between 70 to 80% of field capacity. This will allow the bacteria to get both air and water, which
are very much needed for life.
A soil is at field capacity when soil micropores are filled with water and macropores are filled
with air. The water holding capacity depends upon the nature of the soil. Table 3-3 provides general soil
moisture characteristics for two types of soils.
TABLE 3-3. LTU Soil Characteristics for Effective Bioremediation Treatment
Soil
type1
Water
application
rate
Moisture
holding
capacity
Permeability
Field capacity2
(~ % by weight)
Wilting point2
(~ % by weight)
Sandy
10-12 inches
High
Low
9-25
3-10
Clayey3
8-9 inches
Low
High
38-43
25-28
1 For detailed soil classification, refer to Hazardous Waste Land Treatment, SW-874, September 1980.
2 Soil field capacity and wilting point are dependent upon silt and clay content. These numbers are approximate and proper evaluation
should be conducted in the field.
3 Provided the moisture content is maintained at optimum levels, studies have shown that generally clay soil biodegradation rates are
higher than sandy soil.
32
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Soil moisture content should be monitored regularly and adjusted on an as needed basis to attain
the desirable moisture content. For dry conditions, a fixed or moveable irrigation system may be
installed. For wet conditions/high rainfall areas, underdrainage should be provided. An underdrainage
system could simply be a coarse layer of material such as pea gravel overlaid by a sand layer or a state-of-
the-art leachate collection system constructed at around 1% slope. This will allow the soil to drain and
the leachate to be recirculated. Typically, a one-inch rain may give a combined runoff and leachate of
approximately 10,000 to 27,000 gallons per acre if the LTU is maintained at the proper moisture content.
A water holding pond may be necessary to hold leachate during wet conditions. This water can be used
during dry conditions through an irrigation system.
Soil Nutrients
It is known that biodegradation occurs in the absence of any treatment; however, studies have
shown that careful application of fertilizers can stimulate oil biodegradation two to five-fold with no
adverse environmental impact. (Prince et al).
Although potassium, sulfur, iron, and zinc are needed by microorganisms, the major nutrients
limiting biodegradation are nitrogen and phosphorus. The nutrients nitrogen, phosphorus, and potassium
(N, P, K) are normally added during land treatment in order to enhance microbial activities, which
decompose carbon (C) compounds in the soil. Nitrogen, when added through the ammonium salts, can be
toxic to microorganisms due to the possibility of generation of ammonia in the soil; the ammonium ion
can also promote the increase of oxygen demand. A commonly used strategy is to add nutrients that
provide a stoichiometric ratio of C:N:P:K of 100:5:1:1. However, a small-scale study by Trindate, et al
evaluated the best nutrient ratios during biodegradation of crude oil-contaminated soil (5.38% TPH).
They showed that when nitrogen and phophorus were introduced in too large quantities biodegradation
was inhibited. Further studies are being conducted on this topic (Venosa, personal communication).
For optimum biodegradation, nutrients can be added to the soil using
organic or inorganic fertilizers, and their concentration should be closely
monitored and supplemented as they are depleted during the biodegradation
process. Agriculture fertilizers such as ammonium nitrate, urea, diammonium
phosphate, and potassium phosphate may be added to increase nutrient concentrations in the soil. Studies
have shown that urea and ammonium nitrate give superior results, and ammonium nitrate is the least
expensive at 20 to 30 cents per pound. Superphosphate (0-10-0) and triple superphosphate (0-45-0) are
the most common forms of phosphate fertilizers with the latter being the least expensive at 50 cents per
pound. These fertilizers are usually supplied in prills and pellets and exist in the following types: water
soluble (readily available); granular nutrients (slow release); and oleophilic nutrients. Compared to other
nutrients, water-soluble nutrients are readily available and easier to maintain target nutrient
concentrations in the soil medium. Fertilizers should be added gradually to the soil to minimize pH
changes. The amount and frequency of fertilizer addition depend upon field conditions. However,
33
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evidence from documented land farming has shown that an appropriate fertilizer dosage that could be
repeated, depending upon field conditions, are 500 pounds of nitrogen per acre or 1,100 pounds of urea or
1,500 pounds of ammonium nitrate per acre and 250 pounds of phosphorus per acre. (McMillen et al,
May 2002) Table 3-4 provides most commonly used agricultural inorganic fertilizers that could be used
as soil nutrients.
TABLE 3-4 Suggested Agricultural Inorganic Fertilizers
Fertilizer
N Analysis (%)
P2O5 (P) Analysis ( %)
K20 (K) Analysis ( %)
Ammonium Nitrate
33-34
0
0
Urea
45-46
0
0
Diammonium
Phosphate
18-21
46-54
0
Potassium Nitrate
13
0
44
Organic amendments like wood chips, sawdust, straw, hay, and animal
manure are used to improve soil structure and oxygen infiltration, and to
increase moisture holding capacity in sandy soils. In general, animal manure
should be applied at the rate of about 3-4% by weight of soil and should be
analyzed for nitrogen and phosphorus before its application. Bulking agents like
hay, palm husks, rice hulls, and straw are added to clayey soils to increase pore space and hence, air
exchange. The bulking agent should be blended into the soil until a porous structure is obtained and
visual evidence of oil is eliminated. A rule of thumb to add hay in contaminated media is 5 standard hay
bales per 1,000 square feet of impacted soils. The source of bulking agent may be checked and tested for
residual substances (like pesticides or heavy metals) for toxicity.
Soil pH
Soil pH not only affects the growth of microorganisms, but also has a tremendous effect on the
availability of nutrients, mobility of metals, rate of abiotic transformation of organic waste constituents,
and soil structure. Usually, a pH range of 6-8 units is considered optimum for biodegradation activities.
Soil pH can be adjusted by addition of chemical reagents. For
acidic soils, agriculture lime may be used to raise the pH; aluminum sulfate
or ferrous sulfate or sulfur (a slow acting chemical that requires microbial
activities to generate acid) may be used to lower the pH of alkaline soils.
34
-------
Effect of Temperature
Biological activity is regulated by soil temperature, and an ideal temperature range is between
75 and 95°F. Since the LTU soil temperature is difficult to control under
field conditions, the waste loading rates should be adjusted according to
temperature (see Table 3-1.) This adjustment should also be performed
during the change in season since the biodegradation rates are lower in the
spring and the fall compared to summer.
Oxygen Infiltration - Tilling
After application of waste on the LTU, tilling should be performed at regular intervals to enhance
oxygen infiltration, mixing of hydrocarbons, and homogenization of soils, nutrients, and bulking agents.
Tilling facilitates contact among hydrocarbons, nutrients, water, air, and microorganisms and increases
biodegradation rates.
Tilling should be performed near the lower end of recommended soil
moisture content and should be performed to depths up to 12 inches. Tilling
very wet or saturated soil tends to destroy the soil structure, which generally
reduces oxygen and water intake and reduces microbial activities. Tilling
should not begin until at least 24 hours after the irrigation or a significant
rainfall event. A tractor-mounted rotary tiller provides more aeration during soil mixing and is
recommended for optimum results. Tilling should be conducted in all possible directions (i.e., cross
length and width and diagonally to achieve maximum mixing and stirring of the LTU soils). Tilling
frequency should also be considered in the operating costs of the LTU as an increased frequency will
increase labor costs.
LABORATORY METHODS FOR LTU SOIL
PARAMETERS TESTING
EPA makes recommendations on LTU soil parameter testing, and a list of tests and analytical
methods that can be used for quality assurance and quality control purposes can be found in Appendix D.
In addition, regular monitoring using field kits should be used to amend nutrients, pH, and moisture
contents of the LTU, as these tests are inexpensive and can be performed quickly.
35
-------
MONITORING HYDROCARBON BIODEGRADATION
Baseline Soil Sampling
To ensure that the loss of hydrocarbons is due to bioremediation, a baseline concentration of
hydrocarbons must first be established and biomarkers (hopanes, etc.) in the oil measured. Collecting
samples for that purpose also aids in establishing a baseline for soil concentration and enables evaluation
of the average petroleum loading.
Representative samples based on the LTU size should be collected and composited for TPH and
GC/MS analysis. A soil sampling strategy should be followed as established in the EPA soil sampling
OSWER directive in the beginning. Random soil samples collected at regular time intervals are the
preferred method to assess the LTU contamination.
Quality Assurance and Quality Control
Quality assurance and quality control should be incorporated into the bioremediation project. Use
of acceptable Standard Operating Procedures (SOP) and proper data reporting format are the keys to
QA/QC. Field collection of LTU samples should be conducted under the QA/QC guidelines as prepared
under a Quality Assurance Sampling Plan. Nutrient, pH, microbiological and target compound analysis
should be conducted according to SOP. Detailed descriptions of sampling methods and strategy can be
found in Superfund Program Representative Soil Sampling Guidance OSWER 9360.4-10 directive
EPA/540/R-95/141, December 1995.
http://www.iesinet.com/useful info/GuidanceDocs/1995 1201 EPA SuperfundSamplingGuide.
pdf
Interim Soil Sampling
Evidence of active biodegradation can be obtained by monitoring the following variables:
consumption of oxygen, production of carbon dioxide, relative concentration of hydrocarbons relative to
hopane, increases in microbial activity, production of metabolites, and consumption of nutrients. In the
field, the indication that biodegradation is occurring is provided by monitoring the soil parameters at least
biweekly or monthly depending on the progress and on the parameter (see Table 3-5).
36
-------
TABLE 3-5 Field methods to test LTU parameters.
Variable
Type of test/monitoring
Moisture
Estimate using garden soil water meter OR
% weight of water (see section 1.3.3.1)
Nutrients (N and P)
Field test kits (cost $0.50 to $20 per test), test
time 5 to 30 minutes, easy to use
Oxygen and carbon dioxide
Probe
pH
Direct probe
Air and LTU temperature
Thermocouple or standard thermometer
Hydrocarbons
Gas chromatography
TPH concentration
Standard field test kits
Cleanup Level Confirmation Soil Sampling
A cleanup level confirmation sampling should be performed at the completion of the treatment
period and analyzed to confirm the achievement of cleanup criteria as established at the beginning of the
project by EPA and the state. All biological variables should be evaluated at the termination of the study.
All samples should be collected following a sampling strategy that should provide 95% confidence level
for the LTU soil.
SITE RESTORATION
Once the final batch of hydrocarbon-contaminated media is treated and cleanup standards are
achieved, including stormwater runoff and leachate collection water quality standards, the LTU closure
process should begin. The leachate collection piping including appurtenances, synthetic liner, irrigation
system, and any other equipment installed during construction must be removed and disposed of or
recycled as per applicable rules and regulations. The site should be graded to meet existing topography
and site slope to avoid any soil erosion potential. A final permanent vegetative cover should be
established, which must be a part of final closure plan. Guidance on permanent vegetative cover species
can be obtained from the state agriculture or USDA departments. A good vegetative cover stabilizes the
area and prevents long-term soil erosion hazards.
Assuming that the LTU is properly designed and the only liner is clay with no leachate collection
system or other additional man-made construction material, the closure may be achieved by a
continuation of the normal sequences of biodegradation procedures without physical removal of the liner.
This will include operation and maintenance of the LTU until the clean-up levels are achieved and storm
water runoff quality is acceptable. The side levees should be graded to achieve harmony with existing
topography and should be followed by an establishment of permanent vegetative cover.
37
-------
BIBLIOGRAPHY
1. Arkansas Department of Environmental Quality (ADEQ) Hazardous Waste Division Regulations
rhttp://www.adeq.state.ar.us/hazwaste/branch tech admin/1
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Standard Guide for Risk-Based Corrective Action Applied at Petroleum Release Sites",
rhttp: //www, astm. org/1
3. Banipal, B.S., Myers, J.M. ( E&E, Inc.) and Fisher, Charles (U.S. EPA) Biodegradation of Oil
Refinery Wastes under OPA and CERCLA,, Superfund Conference XVI Proceedings, HMCRI,
Silver Springs, MD, 1995
4. Banipal, B.S., Myers, J.M. ( E&E, Inc.) and Fisher, Charles (U.S. EPA) Biodegradation Rates of
Selected Poly Cyclic Aromatic Compounds, U.S. EPA, Superfund/Haz Waste West Conference
May 21-23, 1996
5. Bioremediation Engineering, Principals, Applications, and Case Studies, General Physics
Corporation, 1990
6. Bioremediation Technical Support for Oil Spills, prepared for Dr. Harry Allen under REAC
Contract #68-C99-223 (contract period 1-13-2000 through 5-31-2004)
7. Deuel, L. and Holiday G.H., Soil Remediation for Petroleum Extraction Industry, Soil Analytical
Services, College Station, TX (1997)
8. Leffler, William L., Petroleum Refining for Non-Technical Person, Penn Well Publishing Co.
1979
9. Louisiana Department of Natural Resources, Office of Conservation, Title 43
rhttp://www.dnr.state.la.us/CONS/Title43.ssil
10. McMillen, Sara; O'Reilly, Kirk; Bernier, Rene; Hoffman, Rob; and Smart, Ross. Bioremediation
as Practiced by ChevronTexaco. Presentation at DOE/PERF Bioremediation Workshop (May 30,
2002.)
11. McMillen, Sara; Smart, Ross; and Bernier, Rene, Biotreating E&P Wastes: Lessons Learned
from 1992-2002 ,9th Annual Internation Petroleum Environmental Conference, Oct 2002,
Albuquerque, NM. rhttp://ipec.utulsa.edu/Ipec/Conf2002/mcmillen smart bernier 122.pdf!
12. National Oil and Hazardous Substances Pollution Contingency Plan (NCP)
rhttp://www.epa.gov/oilspill/ncpover.html
13. New Mexico Oil Conservation Division rhttpV/www.epa.gov/oilspill/opaover.html
14. Oil Pollution Act of 1990 (OPA) rhttp://www.epa.gov/oilspill/opaover.html
15. Oklahoma Corporation Commission
rhttp://204.87.112.100/oar/codedoc02.nsf/All/3B77936100F75BEF86256CF7004F8A8E?QpenD
ocumentl
16. Pope, Daniel F., and J.E. Matthews. 1993. Environmental Regulations and Technology:
Bioremediation Using the Land Treatment Concept. Ada, OK: U.S. Environmental Protection
Agency, Environmental Research Laboratory. EPA/600/R-93/164
17. Prince, Roger C.; Clark, James R.; and Kenneth Lee; Bioremediation Effectiveness: Removing
Hydrocarbons while Minimizing Environmental Impact. 9th Annual Internation Petroleum
Environmental Conference, Oct 2002, Albuquerque, NM.
rhttp://ipec.utulsa.edu/Ipec/Conf2002/prince clark lee 109.pdf!
18. Pritchard, P. Hap and Costa, Charles F., EPA's Alaska Oil Spill Bioremediation Project', final
part of a five-part series by U.S. EPA, Environmental Science Technology, Volume 25, No.3,
1991
38
-------
19. Railroad Commission of Texas, Administrative Code, Title 16, Part 1, Chapter 3, rule 3.91
rhttp://www.rrc.state.tx.us/rules/16ch3.htmll
20. Representative Soil Sampling Guidance, OSWER Directive 9360.4-10 EPA 540/R-95/141
rhttp://www.ert.org/media resrcs/media resrcs.aspl
21. Risk-based methodologies for Evaluating Petroleum Hydrocarbon Impacts at Oil and Natural Gas
E&P Sites, API Publication 4709, February 2001. rhttp://www.api.org/groundwater/l
22. Sublette, Kerry L., Fundamentals of Bioremediation of Hydrocarbon Contaminated Soils, the
University of Tulsa, continuing engineering and science education, March 5-6, 2001.
23. Trindade, P.V.O; Sobral, L.G; Rizzo, A.C.L.; Leite, S.G.F.;Lemos, J.L.S.; Millioli, V.S.; and
Soriano, A.U., Evaluation of the Bio stimulation and Bioaugmentation Techniques in the
Bioremediation Process of Petroleum Hyydrocarbons Contaminated Soil. 9th Annual
International Petroleum Environmental Conference, Oct 2002, Albuquerque, NM.
rhttp://ipec.utulsa.edu/Ipec/Conf2002/trindade soriano 21.pdf!
24. U.S. Environmental Protection Agency OSWER Directive EPA/540/N-95/500 - No. 12,
Bioremediation in the Field, August 1995
rhttp://www.epa.gov/tio/download/newsltrs/bifP596.pdfl
25. U.S. Environmental Protection Agency OSWER Directive SW-874, Hazardous Waste Land
Treatment, September 1980 rhttp://www.epa. gov/epaoswer/hazwaste/test/pdfs/chap 12.pdfl
26. U.S. Environmental Protection Agency Region 3 Removal Site Assessment Guidebook,
published in 1991.
27. U.S. Environmental Protection Agency, Solid Waste and Emergency response Office, "Crude Oil
and Natural Gas exploration and Production Wastes; Exemption from RCRA Subtitle C
Regulations", EPA 530/K-95/003, May 1995
28. . Guide for Conducting Treatability Studies under CERCLA: Final. EPA/540/R-92/071a, 1992.
rhttp://www.epa.gov/superfund/action/guidance/remedv/rifs/overview.html
29. U.S. Environmental Protection Agency, How to Evaluate Alternative Cleanup Technologies for
Underground Storage Tank Sites: A Guide for Corrective Action Plan Reviewers. EPA 510-B-
04-003 and EPA 510-B-95-007, May 1995 rhttp://www.epa.gov/swerustl/pubs/turns.html
30. U.S. Environmental Protection Agency. Technical Guidance Document: Construction Quality
Assurance For Hazardous Waste Facilities. EPA/530-SW86-031, 1986.
31. U.S. Environmental Protection Agency. Understanding Bioremediation: A Guidebook for
Citizens. EPA/540/2-91/02,1991.
rhttp://vosemite.epa.gov/R10/EXTAFF.NSF/0/07alf28a423390a5882565670069de05?QpenDocu
mentl
32. U.S. Environmental Protection Agency. Guide for Conducting Treatability Studies Under
CERCLA: biodegradation Remedy Selection, OSWER Directive EPA/540/R-93/519B, August
1993 rhttp://www.epa.gov/superfund/action/guidance/remedv/rifs/treat.html
33. U.S. Environmental Protection Agency. Guide for Conducting Treatability Studies Under
CERCLA: Aerobic Biodegradation Remedy Screening, OSWER Directive EPA/540/2-91/013A,
July 1991 rhttp: //www, epa. gov/superfund/action/ guidance/remedv/rifs/treat.html
34. U.S. Environmental Protection Agency. Response Team "Inland Oil Spills' course (165.18), June
1992
35. U.S. Guide for Identifying Cleanup Alternatives at Hazardous-Waste Sites and Spills: Biological
Treatment, PNL-460l/EPA-600/3-83-063
36. Venosa, Albert D., Bioremediation in Oil Spill Response, Ph.D., U.S. EPA National Risk
Management Research Laboratory, Cincinnati, OH rhttp://www.epa.gov/oilspill/pdfs/biofact.pdfl
37. Waier, P.R. and K. Smit. Means Site Work & Landscape Cost Data. 11th Edition. R.S. Means
Company, Inc., 1992 rhttp://www.bookworkz.com/books/65283.htmll
39
-------
38. Zhu, X; Venosa, A.D.; Suidan, M.T.; and Lee K.; Guidelines for the Bioremediation of Marine
Shorelines and Freshwater Wetlands, US EPA Report, Sept 2001
rhttp://www.epa.gov/oilspill/pdfs/bioremed.pdfl
Appendix A - Typical Biodegradation Work Plan
40
-------
SUGGESTED ELEMENTS TO BE INCLUDED IN THE WORKPLAN
I.0 Introduction and Objectives
2.0 Site Background
Site History, Site Location, General Climatology,
Site Geology and Hydrogeology, Previous Sludge Analysis
3.0 Rationale for Bio remediation
Remedy Screening Laboratory Treatability Study, if using bioremediation agent, consult
NCP Schedule
Remedy Selection Pilot Bioremediation Assessment
4.0 Construction of Land Treatment Unit
Earthwork, Liner Installation and Leachate Collection System,
Irrigation System (if required)
6.0 Health and Safety
7.0 Bioremediation Operations
pH, Nutrients, Bacterial monitoring
8.0 Soil Sampling and Analysis
Removal Criteria, Soil Sampling - Initial Characterization,
Interim Monitoring and Confirmation Sampling,
Sample Analysis and Quality Assurance/Quality Control
9.0 Material Handling Operations
Excavation of contaminated soils, Loading of the Land Treatment Units,
Ifgx-situ. Tilling of the Treated Soil, Unloading and Reloading of the Land Treatment Unit
10.0 References
II.0 Appendices
-------
Appendix B - Useful Conversion Factors
-------
1. Concentration Conversions
parts per million (ppm) = mg/L = mg/kg
10,000 ppm
ppm hydrocarbon in soil x 0.002
2. Sludge Conversions
1,700 lbs wet sludge
yd3 sludge
Wet tons sludge x 240
Wet ton sludge x % dry solids/100
3. Other Conversions
lyd3
1 gallon water
1 lb
1 ton (English)
lyd3
1 acre
1 acre-inch of liquid
1 ton (metric)
1 %
lbs of hydrocarbons per ton of
contaminated soil
1 yd wet sludge
Wet tons / 0.85
gallons sludge
dry tons sludge
27 ft3
8.34 lbs
0.454 kg
2,000 lbs
0.765 m3
43,560 ft2
27,150 gallons
2,025 lbs
4,840 yd2
3.630 ft3
1,000 kg
4. Nutrient Conversion Factor from off the Shelves
lbs P x 2.3 = lbs P205
lbs Kx 1.2 = lbs K20
5. Other Useful Approximations (not for precise calculations)
1 ft depth in 1 acre (in-situ) = 1,613 x (20 to 25 % excavation factor) = ~2,000
1 yd3 (clayey soils-excavated) = ~1.1 to 1.2 tons (English)
1 yd3 (sandy soils-excavated) = ~1.2 to 1.3 tons (English)
6. Temperature Conversions
(0 C x 1.8 ) + 32
( 0 F - 32) x 0.555
-------
Appendix C - Crude Oil Chemistry
-------
Crude oil and petroleum products consist of a complex mixture of thousands of
compounds, and the composition of crude oil depends on its source. Oils exhibit a wide range of
physical properties, and databases containing that information can be found on the internet or at
sites such as http://www.etcentre.org/databases/spills e.html.
The hydrocarbons in crude oil have different boiling points, according to the number of
carbon atoms their molecules contain and how they are arranged. Fractional distillation uses the
difference in boiling point to separate the hydrocarbons in crude oil.
The petroleum components can be classified in four groups: saturated hydrocarbons,
aromatic hydrocarbons, resins, and asphaltenes. Lighter oils contain a larger proportion of
saturated and aromatic hydrocarbons, whereas heavier oils contain a higher percentage of
asphaltenes. Physical properties of oil affect its behavior in the environment. The following are
evaluated when characterizing oils:
• Specific gravity: ratio of a mass of oil compared to the mass of the same volume of water, at
a specific temperature. The lower the specific gravity, the lighter the oil is on water.
• API gravity (°): (141.5/specific gravity @ 16°C)-131.5
• Viscosity: resistance to change in shape or movement. The lower the viscosity, the easier
the oil flows and spreads.
• Pour point: temperature at which the oil becomes semi-solid and stops flowing.
• Solubility in water: typically, oil is not very soluble in water (30 mg/L). Solubility depends
on temperature, and the most soluble components of oil are typically aromatic hydrocarbons
such as the lower molecular weight monocyclic aromatic hydrocarbons such as benzene,
toluene, and xylenes and low molecular weight poly cyclic aromatic hydrocarbons such as
naphthalene.
• Flash point: lowest temperature at which a flammable liquid produces enough vapors to
ignite in the presence of a source of ignition; a low flash point indicates a highly flammable
liquid.
• Vapor pressure: indication of the evaporation rate of a substance, a high vapor pressure
indicates a high propensity to evaporate
-------
Almost half of the crude oil produced in the United States is generated in Region 6 and
over 42 types of crude oils are handled in the Region 6 states. The following tables list API
gravity and sulfur contents found in various crude oils.
TABLE C-l Crude Oils Handled Near Cushing, Oklahoma
State
Location
Crude Oil Name
Approximate
API Gravity
Sulfur %
OK
Cushing
Common Stream
(pipeline)
37 -42
<0.42
Oklahoma
Domestic
Sweet
Cushing
(lease crude)
43
0.37
Kingfisher
(lease crude)
41
0.12
Seminole
(lease crude)
38
0.33
Osage
(lease crude)
34
0.21
TX
East T exas
Lease Crude
36
0.23
West Texas
Abilene (sweet)
(Intermediate)
37
0.27
Ozona (sour)
23
1.99
AR
Arkansas
USA Midcont.
(sweet)
40
0.4
LA
Louisiana
Light (sweet)
36
0.45
South
33
0.28
NM
New Mexico
USA West Texas
(sour)
34
1.64
Mixed Intermediate
38
0.17
Mixed Light
43
0.07
Note: The API values provided in this table are approximate and were rounded off since there may be variations
depending on when and where the sample was collected.
-------
S.N.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
TABLE C-2 Typical Crude Oils Handled In Region 6
Crude Oil Name
API Gravity
Sulfur %
Domestic Sweet
37-42
<0.42
Brass River
43.5
0.07
Forties
39.5
0.32
Cusian
38.5
0.30
Olmeca
38.3
0.95
Brent
38.0
0.38
AXL
37.7
1.20
Qua
36.7
0.18
Sbar
36.4
0.56
Osberg
36.0
0.25
Bryan Mound
35.9
0.33
Bonny Light
35.2
0.18
Kirkuk
33.7
2.14
Basrah
33.5
2.10
West Texas Sour
ABL
Isthmus
Rabi
Lagocinco
Vasconi
Mesa
KLT
Djeno
Cano
Guafita
ABM
Furriel
Oriente
W.C. Sou
ABH
ANS
Velma
Mesa-25
OLB
Rata
Suni
AMBM
Bacquero
Lagotraco
Leona
Maya
Mariago
33.5
32.5
32.5
33.5
32.0
30.8
30.3
29.5
27.6
29.4
29.1
28.9
28.5
27.5
27.5
27.4
27.5
26.4
25.9
24.4
24.2
24.0
23.5
22.8
22.8
22.6
22.5
22.1
1.78
1.85
1.32
0.07
1.20
0.95
0.98
N/A
0.23
0.55
0.65
2.31
1.05
1.48
N/A
2.70
1.11
N/A
1.43
1.55
4.00
N/A
N/A
1.95
1.34
1.53
2.95
2.85
-------
j ^ T®"' **¦**«« -»*» * f
1 i't
^ 1 § '
m^ I <
0
1 'Ww-wfrimTrrTi.f'-rirTl—rr—nrnw
8 2 S 5 5 3® 8 5 5 5 5 5 § 5 §
i 10 1S 20 25 30
Tlm®frt*)|
TPH AS DIESEL BY GC/FID 8015B
Gas Chromatograph/Mass Spectrum (GC/MS) of Fresh Diesel
"j S3 3
5 f ?
O—i-*
4.
o o u
ih i i i
! r*—r' J ' r" > r
5 10 15 J
J—rrr
30 JS 49 «
TPH AS DIESEL BY GC.'FiD 8015B
Gas Chromatograph/Mass Spectrum (GC/MS) of Weathered Diesel
Source: The Analytical Services Center of Ecology and Environment Inc., 2003
-------
Appendix D - LTU Parameter Analysis Methods
-------
Soil Parameter
Analytical Method
Moisture
EPA 160.3
pH
SW 846 - 9045
Cation Exchange Capacity
SW 846 - 9081
Water Holding Capacity
ASTM 2980
Soil Grain Size
ASTM D422-63
Total Organic Carbon
SW 846 - 9060
Nitrogen Ammonia
EPA 350.1 / 350.3
Total Kjeldahl Nitrogen
EPA 351.2/351.3
Total Phosphorus
EPA 365.1 / 365.2
Nitrate/Nitrogen
EPA 353.2
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