oEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington. DC 20460
EPA/600/K-93/002
April 1993
Seminars
Bioremediation of
Hazardous Waste Sites:
Practical Approaches to
Implementation
May 20-21, 1993—Atlanta, GA
June 7-8, 1993—New York, NY
June 10-11, 1993—Chicago, IL
June 21-22, 1993—San Francisco, CA
June 24-25, 1993—Denver, CO
-------
-------
EPA/600/K-93/002
April 1993
SEMINARS ON
BIOREMEDIATION OF HAZARDOUS WASTE SITES:
PRACTICAL APPROACHES TO IMPLEMENTATION
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC
April 1993
Printed on Recycled Paper
-------
Notice
This document has been reviewed in accordance with the U.S. Environmental
Protection Agency's review policy. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
-------
Table of Contents
Progress in the Field Applications of Bioremediation M
Background on Bioremediatiqn ...;,.... ;..-"£ 2-1
Site Characterization Requirements 3-1
TreatabilityStudies..'. .'..:....-.-.v..-...;-....y....-.-.'•.;•;..;... :.*...:••• 4-1
Scale-up and Design Issues and Cleanup Objectives. —.. 5-1
Reactors for Treatment of Solid, Liquid, and Gaseous Phases 6-1
Soil Treatment: Land Treatment and Development and Evaluation of Composting
Techniques for Treatment of Soils Contaminated with Hazardous Waste 7-1
Bioventing 8-1
Subsurface Bioremediation 9-1
-------
-------
PROGRESS IN THE FIELD APPLICATIONS OF BIOREMEDIATION
John E. Rogers
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH
and
Regional Representatives
U.S. Environmental Protection Agency
1-1
-------
Progress in the Field
Applications of
Bioremediation
John E. Rogers
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH
Selection of Treatment Technologies
for Remedial Actions through 1991
Solidification/Stabilization 26%
Other Established 256,
SoU Washing
Solvent Extraction 1%,
Bioremediation 9%
Flushing 3«
Solvent Vapor
Extraction 17%
Incineration 30%
Bioremediation Database
Developing comprehensive national
listing of CERCLA, RCRA, UST, TSCA,
and pesticide sites using bioremediation
Database includes information on
contaminants, media, treatment
selected, treatment efficiency, and costs
Information available in quarterly
bulletin currently and in computerized
database in late 1993
1-2
-------
Bioremediation Is Being
Considered, Planned, or
Implemented at 159 Sites
Type of Contaminants
100
80
Number 60
of l olLCa
40
20
0
*
55
47
b* *
15 n
rn
Petroleum Wood Solvents Pesticides Other
Preserving
Wastes
Media Type
ISO
100
Number
of Sites
50
111
58
15
10
SoU Ground Sediments Sludge Surface
Water Water
1-3
-------
Stage of Implementation
50
Number
of Sites
50
40
30
20
10
45
36
4
p-— • 1
1 1
24
Design Installed
Type of Treatment
72
70
60
50
40
30
20
10
42
43
13
Number
of Sites 30
Land Reactor In Situ Other
Note: 149 sites have selected or Implemented one or more bloremedlatlon technologies.
Treatment Type
• Ex situ land treatment
• Reactor treatments:
• Activated sludge
• Fluidized bed
• Slurry
• Sequencing batch
• Fixed film
• Attached growth
1-4
-------
Treatment Type (continued)
• In situ technologies:
• Bioventing
• In situ land treatment
• Air sparging
• Addition of nutrients, oxygen,
hydrogen peroxide
• Other bioremediation:
a Aerated lagoon
• Confined treatment facility
• Pile
Potential for Application of
Bioremediation
• Solvents
• Contamination at 1,000 Superfund sites
• Contamination at 1,000s of RCRA
facilities
• Wood Preserving
• 150 Superfund sites
• 1,200 operating facilities
Potential for Application of
Bioremediation (continued)
• Petroleum
• An estimated 2.1 million leaking UST
• 15,000 oil spills annually
• Pesticides
• 150 Superfund sites
• 15,000 dealerships
• Nonpoint sources
1-5
-------
-------
BACKGROUND ON BIOREMEDIATTON
Paul Flathman
OHM Remediation Services Corporation
Findlay, OH
INTRODUCTION
State-of-the-art bioremediation technology is being advanced on many fronts with exciting
research programs and field applications being conducted throughout the world. Active areas of
research and/or application include the development of novel methods for (1) treatment of
chlorinated organics, such as polychlorinated biphenyls (PCBs), chlorinated aliphatics, and pesticides;
(2) enhancing in situ biological treatment; (3) treatment of munitions, wood preserving, refinery, and
manufactured gas plant wastes; and (4) treatment of volatile organic compounds (VOCs) using
biofilters.
The objectives of this section are to:
• Introduce the concepts and terminology of bioremediation/biodegradation
• Discuss factors that influence biodegradation
• Explore benefits/limitations of bioremediation
• Provide an increased comfort level with this technology
The use of bioremediation is thought to be limited by an understanding of biodegradation
processes, appropriate applications, control and enhancement in environmental matrices, and
remediation costs. Bioremediation is an onsite, natural process. The residues from this process are
typically nontoxic. The environment is minimally disturbed, and the process is cost effective
compared to excavation followed by incineration and/or landfilling.
DEFINITION
Bioremediation is the manipulation of living systems to bring about desired chemical and/or
physical changes in a confined and regulated environment. These desired changes include (1) the
decomposition of toxic, hazardous compounds; (2) the improvement in environmental quality; and
2-1
-------
(3) the reduction of human health risks. The process is not new. Land treatment (or solid-phase
treatment) of contaminants in soil has been used for many years by the petroleum industry for the
treatment of their wastes both in this country and throughout the world. Although while many of
the organic compounds released to the environment are readily biodegradable, others are recalcitrant
and persist. Many of these compounds are potentially toxic and their removal has received a high
priority. Physical, chemical, or thermal treatment of these wastes is often very expensive. Biological
approaches often provide effective, low-cost alternatives that also reduce the potential risk to human
health and the environment.
BIOGEOCHEMICAL CYCLING
The biological oxidation and reduction of organic and inorganic compounds by living systems
in the environment is a natural process. These changes primarily are brought about by the naturally
occurring or indigenous bacterial and fungal populations within those environments. Ecology is the
science that explores those interrelationships between organisms and their living (i.e., biotic) and
nonliving (i.e., abiotic) environments (e.g., soil, ground water, and surface impoundment
environments). The term ecological niche not only describes the physical habitat of a population
of microorganisms in such an environment but also the functional role and the interactions of those
microorganisms within that environment or ecological system (i.e., ecosystem).
Elements, such as the carbon found in phenol, an EPA priority pollutant, tend to circulate
in characteristic paths or cycles between the biotic and abiotic portions of the environment. The
term "biogeochemical cycling" describes the conversion and movement of materials by biochemical
forces through the environment. Directly or indirectly, all biogeochemical cycles are driven by the
radiant energy of the sun. Energy is absorbed, converted, and eventually dissipated within ecosys-
tems (i.e., energy flows through ecosystems). The biogeochemical cycles involve physical (e.g.,
dissolution, precipitation, volatilization, fixation) and chemical (e.g.,synthesis, degradation, oxidation-
reduction) transformations of materials as well as various combinations of physical-chemical changes.
The physical and chemical transformations also lead to the spatial translocations of materials, e.g.,
from the water column to the sediment and from soil to the atmosphere. All living organisms
participate in the biogeochemical cycling of materials. Microorganisms, because of their ubiquity,
diverse metabolic capabilities, and high enzymatic activity, play a major role in biogeochemical
cycling.
Most elements are subject to some degree of biogeochemical cycling, but their cycling rates
vary greatly. As might be expected, the major elemental components of living organisms (i.e..;
carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus) are cycled most intensively. Minor
elements (i.e., magnesium, potassium, sodium, and halogens) and trace elements (i.e., aluminum,
boron, cobalt, chromium, copper, molybdenum, nickel, selenium, vanadium, and zinc) are cycled less
intensively. The minor and trace elements iron, manganese, calcium, and silicon are exceptions to
this rule. Iron and magnesium are cycled extensively in an oxidoreductive manner. Calcium and
silicon, while minor components of protoplasm, form important exo- and endoskeletal structures in
both micro- and microorganisms and consequently are cycled on an impressive scale. Nonessential
and toxic elements, such as mercury, lead, and arsenic, also are cycled to some extent as evidenced
by the methylation of mercury.
2-2
-------
AEROBIC AND ANAEROBIC BIOREMEDIATION
With respect to the bioremediation of environments contaminated with hazardous organic
contaminants, it is the energy-yielding portion of the carbon cycle that typically is enhanced. In this
portion of the cycle, microorganisms, i.e., bacteria and fungi, play the key role of decomposers and
convert carbonaceous organic matter into a form (i.e., carbon dioxide) the photosynthesizers or
primary producers can use for the biosynthesis of "new" organic compounds. This decomposition
of organic matter is an energy-yielding process which takes place in both aerobic (i.e., molecular
oxygen-containing) and anaerobic (i.e., molecular oxygen-absent) environments. Some transforma-
tions of carbon occur under aerobic conditions while others occur only under anaerobic conditions.
The generation of methane (or marsh gas) occurs only in anaerobic environments while the
mineralization of alkanes, such as those found in petroleum hydrocarbons, is restricted largely to
aerobic environments. This leads to a biogeochemical separation of living environments. Some
organic compounds, such as the highly chlorinated PCBs, can accumulate in an aerobic environment
and be unavailable to the biological community, while in an anaerobic environment, they can be
transformed through a process referred to as reductive dehalogenation to less highly chlorinated
PCBs, which might be amenable to aerobic biological treatment.
Energy in the form of heat and chemical bond energy is obtained by microorganisms through
the energy-yielding metabolic processes of fermentation and respiration. Respiratory metabolism
yields more energy to microorganisms than fermentative metabolism. In aerobic environments,
respiration tends to be more prevalent than fermentation. Complete respiration results in the
production of carbon dioxide, whereas fermentation normally results in the accumulation of low
molecular weight organic alcohols and acids. If these fermentation products are transferred to
aerobic environments, they are transformed to carbon dioxide by respiration.
The survival of a microorganism in a particular environment depends on how well that
microorganism can meet its energy and organic and/or inorganic chemical requirements. Energy
production by microorganisms is almost synonymous with the generation of adenosine triphosphate
(ATP). ATP often is called the universal energy currency of the cell. Microorganisms are classified
as autotrophs or heterotrophs based on whether they require preformed organic matter.
Autotrophic microorganisms derive energy from either light absorption or oxidation of inorganic
compounds. The chemoautotrophs of the nitrogen (i.e., nitrifers) and sulfur (i.e., sulfide- and sulfur-
oxidizing bacteria) cycles are common examples of microflora that obtain their energy for the
generation of ATP by the oxidation of inorganic compounds.
In heterotrophic metabolism, organic compounds, such as those on the list of EPA priority
pollutants, are required for generating ATP. The parent compound (i.e., substrate) is transformed
through a series of intermediary metabolites. Some metabolic pathways are common to most
heterotrophic microorganisms. Such a pathway is the Embden-Meyerhof pathway of glycblysis which
involves the conversion of glucose to pyruvate with a net gain of two moles of ATP and two moles
of reduced nicotinamide adenine dinucleotide (NADH) per mole of glucose. The Embden-Meyerhof
pathway is not the only glycolytic pathway, and pyruvate formed in these pathways is further
metabolized. Under anaerobic conditions, these transformations often use the NADH (reducing
power) generated during glycolysis to form a variety of organic end products and regenerate NAD.
When there is no net oxidation in the overall pathway, the process is called fermentation. Different
microorganisms carry out different fermentations. The end products of one organism's metabolism
can be used to generate ATP by another organism, or even the same organism under different
environmental conditions. Fermentation end products, such as ethanol, can be completely oxidized
(i.e., mineralized) under aerobic conditions to yield additional ATP.
2-3
-------
Under aerobic conditions, pyruvate can be oxidized to carbon dioxide with the generation
of additional energy and NADH by passage through the tricarboxylic acid (TCA) cycle, which is also
known as the Krebs or citric acid cycle. In that cycle, NADH is formed which, together with the
NADH formed during glycolysis, can yield additional ATP by the passage of the electrons released
through an electron transport chain, a process known as oxidatiye phpsphorylation. The electrons
released from the oxidation of NAE>H to NAD pass through a series of alternately oxidized and
reduced flavoprotein and iron-containing cytochrome molecules and finally are used to reduce
molecular oxygen (a terminal electron acceptor) to water. In a process not as well understood as
aerobic metabolism, some anaerobic microorganisms can use nitrate, sulfate, or bicarbonate ions as
terminal electron acceptors. Nitrate has been shown to serve as a terminal electron acceptor for the
anaerobic biodegradation of benzene, toluene, ethylene, andxylene (BTEX) and lower molecular
weight polyaromatic hydrocarbons (PAHs) under denitrifying conditions. Sulfate also has been
shown to serve as a terminal electron acceptor for the anaerobic biodegradation of BTEX under
sulfate-reducing conditions. The reductive dehalogenation of PCBs, for example, is thought to occur
under methanogenic conditions. .
In summary, bioremediation is the enhancement of a natural process in a controlled
environment for the purpose of improving environmental quality and reducing the risks to human
health following the introduction of a toxic, hazardous compound into that environment.
REFERENCES
Alexander, M. 1991. Research needs in bioremediation. Environmental Science and Technology
25(12):1972-1973.
Atlas, R.M. and R. Bartha. 1987. Microbial Ecology: Fundamentals and Applications, 2nd Edition.
Menlo Park, CA: The Benjamin/Cummings Publishing Company, 533 pp.
Flathman, P.E., D.E. Jerger, and J.H. Exner, eds. 1993. Bioremediation: Field Experience.
Chelsea, ME: Lewis Publishers. In preparation.
Flathman, P.E. 1992. Bioremediation technology advances via broad research and applications.
Genetic Engineering News 12(6):6,7, and 11.
Freeman, H.M. and P.R. Sferra, eds. 1991. Innovative Hazardous Waste Treatment Technology
Series, Volume 3, Biological Processes. Lancaster, PA: Technomic Publishing Co., 202 pp.
Gottschalk, G. 1986. Bacterial Metabolism, 2nd Edition. New York, NY: Springer-Verlag, 359 pp.
Hinchee, R.E. and R.F. Olfenbuttel, eds. 1991. In Situ Bioreclamation. Stoneham, MA:
Butterworth-Heinemann, 623 pp.
Hinchee, R.E. and R.F. Olfenbuttel, eds. 1991. On-Site Bioreclamation. Stoneham, MA:
Butterworth-Heinemann, 539 pp.
Horvath, R.S. 1973. Enhancement of co-metabolism of chlorobenzoates by the co-substrate
enrichment technique. Applied Microbiology 26(6):961-963.
2-4
-------
Horvath, R.S. 1972. Microbial co-metabolism and the degradation of organic compounds in nature.
Bacteriological Reviews 36(2):146-155.
Kuhn, E.P. and J.M. Suflita. 1989. Dehalogenation of pesticides by anaerobic microorganisms in
soils and ground-water - a review. In: B.L. Sawhney and K. Brown, eds., Reactions and Movement
of Organic Chemicals in Soils, SSSA Special Publication no. 22. Madison, WI: Soil Science Society
of America and American Society of Agronomy, pp. 111-180.
Mohn, W.W. and J.M. Tiedje. 1992. Microbial reductive dehalogenation. Microbiological Reviews
56(3):482-507.
Sayler, G.S., R. Fox, and J.W. Blackburn, eds., 1991. Environmental Biotechnology for Waste
Treatment. New York, NY: Plenum Publishing Corporation, 298 pp.
Thomas, J.M. and C.H. Ward. 1989. In situ biorestoration of organic contaminants in the
subsurface. Environmental Science and Technology 23(7):760-766.
Zitomer, D.H. and R.E. Speece. 1993. Sequential environments for enhanced biotransformation
of aqueous contaminants. Environmental Science and Technology 27(2):226-244.
2-5
-------
Background
PaulE.Flathman
OHM Remediation Services Corp.
Findlay, OH
Objectives
• Introduce concepts and terminology
of bioremediation/biodegradation
• Discuss factors that influence
biodegradation
• Explore benefits/limitations of
bioremediation
• Provide increased comfort level
with this technology
Use of Bioremediation limited
by Understanding of:
• Biodegradation processes
• Appropriate applications
• Control and enhancement
in environmental matrices
• Remediation costs
2-6
-------
Benefits of Bioremediation
• On site
• Natural process
• Residues typically nontoxic
• Environment minimally disturbed
• Typically cost effective compared
to excavation followed by
incineration and/or landfilling
Bioremediation
Manipulation of living
systems to bring about
desired chemical and/or
physical changes in a
confined and regulated
environment
Desired Changes
Decomposition of toxic,
hazardous compounds
Improvement in
environmental quality
Reduction of human health
risks
2-7
-------
Hybrid of:
Microbiology
Engineering
Soil science
Ecology
Hydrogeology
Toxicology
Biodegradation
Biological transformation of an
organic compound to another form
without regard to extent
OH
m-cWorophenol
3-cMorophenol
OH
m-chlorocatechol
3-chlorocatechol
Mineralization
• Conversion of an organic compound to
carbon dioxide, water, methane, and other
inorganic forms (e.g., C1-, NH4+)
i Aerobic °.H
conditions
i Anaerobic
(methanogenic) ^s,
conditions ' fl -»~CH< +
+ O2 -»- CO2 + H2O + O- + ATP + Biomass
a
OH
CO2 + a- + ATP + Biomass
Cl
2-8
-------
Xenobiotic Compounds
»Compounds foreign to
biosphere having been present
for an instant on evolutionary
time scale
> Can be persistent or
recalcitrant compounds
Xenobiotic Compounds (cony
• Polychlorinated biphenyls
(PCBs)
• Chlorinated pesticides/wood
preservatives
• Pentachlorophenol (PCP)
• Dioxrns
• Toxaphene
Xenobiotic Compounds (com.)
• Chlorinated aliphatics
• Methylene chloride
(dichloromethane, DCM)
• Tetrachloroethylene
(perchloroethylene)
B 1,1,2,2-Tetrachloroethane
• Munitions
• TNT
2-9
-------
Recalcitrant/Refractory
Compound
> Compound inherently
resistant to any degree of
biodegradation
»Compounds so listed
continuously change
•TCE
•PCBs
Persistent Compound
• Compound that fails to undergo
biodegradation under a specified set
of conditions
• Compound may be inherently
biodegradable yet persist in the
environment
Aerobic conditions
Unweathercd /
Aroclorl242 \ Anaerobic conditions
- Minimal degradation
Reductive dehalogenation
- Extensive transformation
Ecology
Derived from the Greek
• O/kos-Household or dwelling
•Logos-Law
Science that explores
interrelationships between
organisms and their living and
nonliving environments
2-10
-------
Biogeochemical
Cycles
[Sun
r* Radiant Energy
I
Photosynthesizers -
Green plants, algae,
Decomposers ZZZZT'— r- Herbivores
Bacte.ru
fungi
i
land
Microbial Ecology
Bioremediation
.
Carnivores
Biogeochemical Cycles *" Omiiivores
C (photosynthesis/respiration/ A
fermentation), N, S, P, Fe,Ca, c *
heavy metals (Hg, Cr.As, etc.) Scavengers
Biogeochemical Cycles of
C, H, and O
Aerobic Anaerobic
Fossil
Fuels
C02+H20 |02+CH20|
V
Respiration
^Methanogenesis
ATP Coupling of Energy-Yielding
Metabolism and Biosynthesis
Energy-Yielding
Metabolism
Energy
(e.g., lig]
phe
Oxid
i
Metabolic
Sources
it, NH4*,
nol)
ition f ATI
V \
Uttlizable V
Energy ^-ADl
Products
Biosynthetic Metabolism
Biopolymers
(e.g., proteins)
f * 1
, ^J Biosynthetic Intermediates
^^v (e.g., amino acids)
1 » *
) * T
J Intracellular Precursor
' -^ >w Pool
External Nutrients
(e.g.,NH,*,N03-,S04-2)
2-11
-------
Nitrogen Cycle
Reduced Organic Nitrogen in Living Matter
(e.g., NH, groups ofamino acids)
Plants Animal excretory products
^k. Animals-^ ^^-Microorganisms
Sulfur Cycle
Reduced Organic Sulfur in Living Matter
(e,g., SH group ofcysteine)
Plants-*- Animals-^- Microorganisms
Utilization of sulfate
(plants, microorganisms)
Decomposition of organic matter
(microorganisms)
Oxidation ox ti-jS
(colorless and
photosynthetic sulfur
bacteria, or
spontaneous)
Sources of Carbon and
Energy for Growth
Energy Source for
ATP Generation
Carbon Source for
Cellular Organic Matter
Chcmoautotrophs
Nitrifying bacteria
and sulfur-, iron-,
and
hydrogen-oxidizing
bacteria
Inorganic Compounds
(e.g., NH,*, NO2-,
H2S, S, Fe*z, H2)
C02
Chemoheterotrophs
Fungi and bacteria
Preformed
Organic Matter
(e.g., phenol)
Preformed
Organic Matter
(e.g., phenol)
2-12
-------
Energy-Yielding Metabolism
Many Organic Compounds
i—^-ATP.NADH
Pyruvate
1—^- NADH,CO2
Acetyl Coenzyme A
Terminal Electron
Acceptors
02, NO3-, SO4-2, HCO,-
C02
ATP
Energy-Yielding Metabolism (com.)
I. Fermentation
Organic compounds serve both
as electron donors and electron
acceptors for the oxidation of
substrates
C6H12O6 -»- CO2 + C2H5OH + ATP + Biomass
Glucose Ethanol
(blood sugar) (grain alcohol)
Energy-Yielding Metabolism (com.)
I. Fermentation (continued)
mO2 Relationship
» Obligate Anaerobes
» Facultative Anaerobes
• On exposure to O2, most
rnicroflora shift to aerobic
respiration
2-13
-------
Energy-Yielding Metabolism
II. Respiration
Organic compounds or reduced inorganic
compounds serve as electron donors for
the oxidation of substrates
•Aerobic Respiration
» O2 is terminal electron acceptor
» H2O is produced
• Anaerobic Respiration
» Denitrification
• NO3- (nitrate) is terminal electron acceptor
• N2 (nitrogen gas) is produced
Energy-Yielding Metabolism (com.)
n. Respiration (continued)
• Anaerobic Respiration (continued)
» Sulfate Reduction
• SO4-2 (sulfate) is terminal electron
acceptor
• S-z (suffide) is produced (e.g., H2S, FeS)
» Methanogenesis
• HCO3- (bicarbonate) is terminal electron
acceptor
• CH4 (methane, marsh gas) is produced
Requirements for
Bioremediation
i Available contaminant (substrate)
> Acceptable temperature
i Electron acceptor
(02, N03-, S04-2, HCO3-)
Nontoxic concentration of
contaminant
2-14
-------
Requirements for
Bioremediation (com.)
> Available mineral nutrients
• Acceptable pH
> Surfactant if contaminant
not water soluble
> Cosubstrate if contaminant
cometabolized
Requirements for
Bioremediation (com.)
• Primary substrate if contaminant and
available TOC present at trace levels
• Hydraulic conductivity >10~4 cm/sec
for in situ subsurface soil/ground
water treatment
• Soil moisture content 60 to 80% of
soil moisture holding capacity for
solid-phase (or land) treatment
Cometabolism/Cooxidation
• Transformation of a nongrowth-supporting
substrate in the obligate presence of a
growth-supporting substrate (cosubstrate)
10
20
30
Days
Without
cosubstrate addition
O mchlorobenzoate
n nKblofocatechol
.00
10 20
Days
With
cosubstrate addition
2-15
-------
Biodegradable Organics
Group I
Highly Soluble, Degradable Compounds
• Alcohols— Methanol
• Ethers— Tetrahydrofuran (THF)
• Ketones— Acetone
Methylethylketone (MEK)
Methyh'sobutylketone (MffiK)
• Nitrogenous— Acrylonitrile
• Substituted Benzenes— Isophorone
Toluic Acids
Chlorobenzenes
Biodegradable Organics (com.)
Group II
Readily Biodegradable Compounds
• Benzene, Etbylbenzene, Toluene, Xylenes (BETX)
• Virtually All Petroleum Cuts
• Chlorinated Aliphatics—
Methylene Chloride
(or Dichloromethane, DCM)
Hexachloro-l,3-butadiene
• Naphthalenes— 2-Chloronaphthalene
• Phenols— 2-Chlorophenol
• Phthalates— Diethylphthalate
2-16
-------
SITE CHARACTERIZATION REQUIREMENTS
Ronald C. Sims
Utah State University
Logan, UT
INTRODUCTION
An adequate site characterization, including surface soil and subsurface aquifer
characteristics, subsurface hydrogeology, type of contaminants present, and the extent and
distribution of contamination, is the basis for the rational design of a bioremediation system. Site-
specific characteristics can function as constraints that limit the rate and/or the extent of
bioremediation of the site. Therefore, a thorough site characterization is necessary to determine
both the three-dimensional extent of contamination and engineering constraints and opportunities.
EVALUATION OF EXTENT AND DISTRIBUTION OF CONTAMINATION
Evaluating the extent and distribution of contamination at a site will provide important
information that can be used to select specific bioremediation technologies, for example,
prepared-bed, bioventing, compost, in situ reactors, above-ground soil slurry reactors, or
above-ground water treatment reactors, or to select a treatment train that represents a combination
of physical/chemical and biological technologies. Extent of contamination generally is determined
through three-dimensional sampling and characterization of the several physical phases present at
a site. If contamination is widespread and low in concentration, then in situ treatment might be
feasible. Conversely, a high concentration of contaminants present in a vadose zone that is directly
sponsoring contaminants to the ground water might require soil excavation and placement in a
prepared-bed reactor. Also, sampling the ground water phase at a site to determine extent of
contamination is necessary, but not sufficient. A contaminated site is a system generally consisting
of four phases: (1) solid, which has two components, an organic matter compartment and an
inorganic mineral compartment composed of sand, silt, and clay; (2) oil (commonly referred to as
nonaqueous phase liquid, or NAPL), (3) gas, and (4) aqueous (leachate or ground water). Figure
1 shows the phases that need to be characterized with regard to extent and distribution of
contamination. Each phase in Figure 1 also can be a site for biological reactions that result in the
transformation of a parent chemical and therefore destruction of the parent compound. Each
contaminated phase in the subsurface might require a different bioremediation technology to
optimize site remediation.
3-1
-------
Distribution of contaminants at a site is determined not only by the original placement and
escape of contaminants, which can be determined through a three-dimensional sampling program,
but also by physical and chemical properties of the contaminants. Physical and chemical properties
of contaminants will determine whether contaminants are teachable, volatile, or adsorbable, and
therefore will indicate which subsurface phase(s) contain the contaminant(s). Those physical phases
containing the contaminants require evaluation of bio remediation potential. When the physical and
chemical properties are evaluated within the context of site characteristics, a site-based waste
characterization can be used to identify the phases at the site and the chemicals associated with each
phase.
MICROORGANISMS
Microbiological characterization of a contaminated site should be conducted to ensure that
the site has a viable community of microorganisms to accomplish biodegradation of the organic
contaminants present at the site. Soil microorganism groups most commonly involved in
bioremediation include bacteria, actinomycetes, and fungi. Approaches for characterizing the kinds,
numbers, and metabolic activities of soil microorganisms include (1) determination of the form
arrangement and biomass of microorganisms in soil, (2) isolation and characterization of subgroups
and species, and (3) detection and measurement of metabolic processes. Generally, information
concerning measurement of microbial activity in situ or under conditions designed to simulate field
characteristics is more useful than information concerning microbial enumeration (counting), because
microbial density within a subsurface system generally is not well correlated with microbial activity
within the system.
Examples of techniques recharacterize microorganism activity include measurement of 14CO2
evolution (mineralization) of spiked radiolabeled parent compound, disappearance of the parent
compound and production of metabolic intermediates, and the use of bioassays to measure the
toxicity of a contaminated system or subsurface phase (e.g., leachate or ground water) to soil
microorganisms or soil enzymes. Microbial enumeration can be accomplished by direct microscopy
of soil (e.g., fluorescent staining and buried-slide techniques), biomass measurement by chemical
techniques (e.g., measurement of ATP), and cultural counts of microorganisms (e.g., plate counts,
dilution counts, isolation of specific organisms).
Microbial ecologists have identified ranges of critical environmental conditions that affect
the activity of soil microorganisms (Table 1). Many of these conditions are controllable and can be
changed to enhance the biodegradation of organic constituents. A discussion of the factors covered
below including principles, status of the technology, secondary impacts, equipment, advantages and
disadvantages, and references are provided in U.S. EPA (1990).
OXYGEN PROFILE
With regard to unsaturated soil, microbial respiration, plant root respiration, and respiration
of other organisms remove oxygen from the soil atmosphere and enrich it with carbon dioxide. Gases
diffuse into the soil from the air above it, and gases in the soil atmosphere diffuse into the air.
Oxygen concentration in a soil, however, can be much less than in air while carbon dioxide
concentrations in soil can be many times that in air. A large fraction of the microbial population
within the soil depends on oxygen as the terminal electron acceptor in metabolism. When soil pores
become filled with water, the diffusion of gases through the soil is restricted. Oxygen diffuses
3-2
-------
through air 10,000 times faster than it does through water. Oxygen can be consumed faster than it
can be replaced by diffusion from the atmosphere, and the soil can become anaerobic. Clay content
of soil and the presence of organic matter also can affect oxygen content in soil. Clayey soils tend
to retain a higher moisture content, which restricts oxygen diffusion, while organic matter can
increase microbial activity and deplete available oxygen. Facultative anaerobic organisms, which can
use oxygen when it is present or can switch to alternative electron acceptors such as nitrate or sulfate
in the absence of oxygen, and obligate anaerobic organisms become the dominant populations.
Additional information concerning in situ anaerobic bioremediation can be found elsewhere (U.S.
EPA, 1990).
Oxygen concentrations in soil systems can be increased by tilling and draining unsaturated
soil, for example in prepared-bed, compost, and in situ systems. Oxygen concentrations in soil
systems also can be increased through the application of bioventing systems, where air is forced
through a soil system and carries oxygen to soil microorganisms to accomplish aerobic degradation.
Air has a much greater potential than water for delivering oxygen to soil on a weight-to-weight and
volume-to-volume basis. Oxygen provided by air is more easily delivered since the fluid is less
viscous than water. High oxygen concentrations in air also provide a large driving force for
diffusions of oxygen into less permeable areas within a soil formation. Hinchee (1989) and Hinchee
and Downey (1990) successfully applied bioventing for enhancement of biodegradation of petroleum
hydrocarbons in JP-4 jet fuel contaminated soil at Hill Air Force Base, Ogden, Utah, in increasing
subsurface oxygen concentrations. Oxygen and carbon dioxide concentrations were monitored and
correlated well with hydrocarbon biodegradation.
Within saturated environments, oxygen transport is considered to be the rate-limiting step
in aerobic bioremediation of contaminated hydrocarbons. Oxygen profiles have been used at the
Traverse City, Michigan, site contaminated with jet fuel (U.S. EPA, 1991a). Increasing the oxygen
concentration in water through addition of hydrogen peroxide (E^Oj) and enhancing oxygen delivery
to the contaminated subsurface through management of hydraulic gradients positively affected the
rate of biodegradation of the jet fuel components benzene, toluene, and xylene (BTX). Although
high concentrations of H^ can be toxic to microorganisms, acclimation is possible by slowly
increasing the concentration of HjOj with time.
NUTRIENTS
Microbial metabolism and growth are dependent on adequate supplies of essential macro-
and micronutrients. Required nutrients must be present and available to microorganisms in a
suitable form, appropriate concentrations, and proper ratios. If the wastes present at a site are high
in carbonaceous materials and low in nitrogen (N) and phosphorus (P), the subsurface can become
depleted of available N and P required for biodegradation of the organic contaminants. Addition
of nutrients can be required as a management technique to enhance microbial degradation.
Commercial agricultural fertilizers are available. Power implements, tillers, and applicators can be
used to apply the nutrients to land-based systems, or nutrients can be added to treated water from
a pump-and-treat system and applied through reinfiltration or irrigation (U.S. EPA, 1991b).
Recommended ratios for subsurface systems of carbon (C), N, and P are 120:10:1 on a weight basis.
Examples of sites where nutrients have been added to enhance microbial degradation of hydrocarbon
contaminants include Traverse City (saturated environment in in situ bioremediation) (U.S. EPA,
1991a) and the Champion International Superfund Site in Libby, Montana (Sims et al., 1993). At
the site in Libby, Montana, nutrients are added to enhance bioremediation in a prepared-bed system,
3-3
-------
in an above-ground reactor for treating extracted ground water, and in injection wells designed for
in situ bioremediation.
MOISTURE
Water is necessary for microbial life, and the soil water matrix potential against which
microorganisms must extract water from'the soil regulates their activity. The soil matrix potential
is the energy required to extract water from the soil pores to overcome capillary and adsorptive
forces. Soil water also serves as the transport medium through which many nutrients and organic
constituents diffuse to the microbial cell, and through which metabolic waste products are removed.
Soil water also affects soil aeration status, nature, and amount of soluble materials; soil water
osmotic pressure; and the pH of the soil solution (U.S. EPA, 1989). Generally, microbial activity
measured as biodegradation rates and rates of detoxification of contaminants in soil has been found
to be highest at soil moisture contents of 60 to 80 percent of field capacity, compared with those of
20 to 40 percent of field capacity (U.S. EPA, 1991a).
Soil moisture can be increased using standard agricultural irrigation practices such as
overhead sprinklers or subirrigation. To remove excess water or lower the water table to prevent
water-logging, drainage or well point systems can be used. Also, the addition of vegetation to a site
will increase evapotranspiration of water and therefore assist in retarding the downward migration
of water (i.e., leaching) (U.S. EPA, 1990). Soil moisture control can be combined with
pump-and-treat systems where contaminated ground water is extracted, treated to remove
contamination, and amended with nutrients and an oxygen source before it is reinfiltrated or used
for irrigation (U.S. EPA, 1991b).
ENVIRONMENTAL FACTORS
Environmental factors including pH, redox potential, and temperature are important
parameters that will affect the rate and extent of bioremediation in unsaturated and saturated.
subsurface systems. Outside of the pH range of 5.5 to 8.5, microbial activity is generally decreased.
Maintaining soils near neutral pH is most often recommended for enhanced bioremediation (U.S.
EPA, 1990). Acidic soils are known to become acclimated to bacteria and fungi over time, however.
Soil pH values greater than 6 are recommended for immobilization of metals. Conventional
agricultural practices for increasing soil pH include adding lime periodically and mixing the lime with
the acidic soil. The amount of lime required to effect a pH change in a particular site/soil/vyaste
system must be determined by a soil-testing laboratory (U.S. EPA, 1990).
Redox potential of a subsurface environment has a large influence on microbial metabolism
and activity. For aerobic metabolism, the redox potential should be greater than 50 millivolts; for
anaerobic conditions, less than 50 millivolts. A low redox potential provides alternative electron
acceptors to oxygen; for example, nitrate, nitrite, iron, manganese, and sulfate can act as electron
acceptors. A redox potential higher than 50 millivolts is conducive to biodegradation of
hydrocarbons; less than 50 millivolts is conducive to degradation of chlorinated hydrocarbons, and
generally less than 35 millivolts (U.S. EPA, 1990) is required.
Soil temperature has an important effect on microbial activity and has been correlated with
biodegradation rates of specific organic compounds (U.S. EPA, 1991a). Prepared-bed and in situ
bioremediation should be planned to take advantage of the warm season in cooler climates.
3-4
-------
Vegetation can act as an insulator against heat loss and limit frost penetration. Application of
mulches can help control heat loss at night and heat gain during the day (U.S. EPA, 1991a; 1990).
SUMMARY AND SOURCES OF ADDITIONAL INFORMATION
An adequate site characterization, including the contaminant distribution as influenced by
site geology and hydrogeology and chemical properties, is the basis for the rational design of a
bioremediation system. Site characterization information assists in the identification of specific
physical phases requiring remediation. Site-specific characteristics can function as constraints that
limit the rate and/or the extent of bioremediation of the site. Information concerning microorganism
activity, oxygen profiles, nutrients, moisture, and environmental conditions including pH, redox
potential, and temperature are necessary for selecting bioremediation techniques, and for selecting
treatment trains that combine physical/chemical treatments with biological treatment.
Additional information concerning practical aspects of site characterization
bioremediation of contaminated ground water is available in Sims et al. (1992).
for
REFERENCES
Hinchee, R. 1989. Enhanced biodegradation through soil venting. Proceedings of the Workshop
on Soil Vacuum Extraction. U.S. EPA, Robert S. Kerr Environmental Research Laboratory, Ada,
OK, April 27-28.
Hinchee, R. andD. Downey. 1990. In situ enhanced biodegradation of petroleum distillates in the
vadose zone. Proceedings of the International Symposium on Hazardous Waste Treatment:
Treatment of Contaminated Soils. Air and Waste Management Association, U.S. EPA, Risk
Reduction Engineering Laboratory, February 5-8.
Sims, R.C., I.E. Matthews, S.C. Ruling, B.E. Bledsoe, M.E. Randolph, and D.E. Pope. 1993.
Evaluation of full-scale in situ and ex situ bioremediation of creosote wastes in soil and ground water.
Proceedings of the Annual Symposium on Bioremediation of Hazardous Wastes: Research,
Development, and Field Evaluations. Dallas, Texas, May 4-5.
Sims, J.L., J.M. Suflita, and H.H. Russell. 1992. In situ bioremediation of contaminated ground
water. Office of Solid Waste and Emergency Response and Office of Research and Development.
EPA/540/S-92/003. February.
U.S. EPA. 1991a. U.S. Environmental Protection Agency. Site characterization for subsurface
remediation. Seminar Publication. Office of Research and Development, Washington, DC.
EPA/625/4-91/026. October.
U.S. EPA. 1991b. U.S. Environmental Protection Agency. Handbook: stabilization technologies
for RCRA corrective actions. Office of Research and Development, Washington, DC.
EPA/625/6-91/026. August. ,
U.S. EPA. 1990. U.S. Environmental Protection Agency.
hazardous waste-contaminated soils. EPA/540/2-90-002.
Handbook on in situ treatment of
3-5
-------
U.S. EPA. 1989. U.S. Environmental Protection Agency. Bioremediation of contaminated surface
soils. Robert S. Kerr Environmental Research Laboratory. EPA/6QO/9-89/073. August.
3-6
-------
Table 1. Critical Environmental Factors for Soil Microbial Activity
Environmental Factor
Optimum Levels
Oxygen
Nutrients
Moisture
Environment (pH)
Environment (Redox)
Environment (Temperature)
Aerobic metabolism: greater than 0.2 mg/L dissolved oxygen,
minimum air-filled pore space of 10%;
Anaerobic metabolism: less than 0.2 mg/L dissolved oxygen,
O2 concentration less than 1% air-filled pore space.
Sufficient nitrogen, phosphorus, and other nutrients so not
limiting microbial growth (suggested C:N:P ratio of 120:10:1)
Unsaturated soil: 25-85% of water holding capacity;
-0.01 MPa; will affect oxygen transfer into soil (aerobic status)
In saturated zone, water will affect transport rate of oxygen,
and therefore will affect rate of aerobic remediation
5.5-8.5 '.'.-'.; ;'"'-•: '.•..••'
Aerobes and facultative anaerobes: greater than 50 millivolts;
Anaerobes: less than 50 millivolts
15 - 45 C (mesophilic)
Source: U.S. EPA (1989).
3-7
-------
Fluid Phase
water
leachate
Solid Phase
organic matter
Gas
carbon dioxide
oxygen
Texture
sand
silt
clay
Oil
petroleum hydrocarbons
(Non-Aqueous Phase Liquids)
(NAPLs)
Figure 1. Phases for characterization and for evaluation of bioremediation at each site (U.S.
EPA, 1991).
3-8
-------
Site
Characterization
Requirements
(• V < .
Ronald C. Sims
Utah State University
Logan, UT
Approach
Observation
Response
Site = Black Box
3-9
-------
Site Characterization
Requirements
• Evaluation of Extent and
Distribution of Contamination
• Microorganisms
• Oxygen Profile
• Nutrients
• Moisture
• Environmental Factors
Critical Environmental Factors
for Soil Microbial Activity
Environmental
Factor
Effects
Oxygen
Nutrients
Moisture
Metabolism:
Aerobic/Anaerobic
Degradation Pathways
Nitrogen, Phosphorus
Activity
Unsaturated/Saturated
Soil
Oxygen Transfer
Critical Environmental Factors
for Soil Microbial Activity
Environmental
Factor
Effects
Environment
(PH)
Environment
(Redox)
Environment
(Temperature)
5.5-8.5
Activity
Aerobes/Facultative
Anaerobes: >50 mV
Anaerobes: <50 mV
Degradation Pathways
15-45°C(Mesophilic)
Activity
3-10
-------
Contaminated Site Characterization
Soil Phases
• Solid
• Liquid
• Gas
• NAPL
Evaluation of
Extent and Distribution of
Contamination
Physical Phases at a Site to Be Considered
for Bioremediation Technologies
Fluid Phase
• Water
• Leachate
Solid Phase
• Organic
Matter
Oil
• Petroleum
Hydrocarbons
• Nonaqueous
Phase Liquids
(NAPLs)
3-11
-------
Mass Transport and Toxicity Limitations
to Biological Treatment of Soils as a
Function of NAPL Concentration
Nutrients •
Mass
Transport
_ Electron
"Acceptor
Nonaqueous Phase Liquid (NAPL)
[Resistance to Mass Transport]
"soil Particle"^
Toxicity to Microorganisms
Nutrients •
Mass
Transport
. Electron
Acceptor
Microorganisms
3-12
-------
Soil Microorganisms
•Bacteria
•Actinomycetes
•Fungi
Soil Microorganisms
•Enumeration
•Identification
•Relationship of Population
Size (Numbers Per Gram of
Soil) to Activity Is Not Well
Established
3-13
-------
Oxygen Profile
3-14
-------
pissplved^Oxyqen
v(mg/L)
Mn+a
(mg/L)
3-15
-------
Nutrients
J
"\
Moisture
3-16
-------
Environmental Factors
3-17
-------
Oxygen Supply
Oxygen Diffuses
through Water at a Rate
That Is 10,000 Times
Less Than the Rate at
Which Oxygen Diffuses
through Air
Redox and Biodegradation
- Maximum rate of degradation often correlated
with continuous supply of oxygen
Degradation may result In anaerobic conditions
(i.e., lower redox potential)
<• Degradative pathways for some chemicals
occur under reducing conditions (e.g.,
reductive dechlorlnatlon)
3-18
-------
SOIL TREATMENT FACTORS
• TOXICiTY TO MICROORGANISM
^CHEMICAL v
>DOSE .-->-.•
« NUTRIENTS
* OXYGEN
<• CHEMICAL
3-19
-------
-------
TREATABILITY STUDIES
John Rogers
U.S. Environmental Protection Agency
Athens, GA
and
P. Hap Pritchard
U.S. Environmental Protection Agency
Gulf Breeze, FL
and
Paul Flathman
OHM Remediation Services Corporation
Findlay, OH
INTRODUCTION
Because of the tight time constraints in effecting the cleanup of Superfund hazardous waste
sites, making timely decisions in selecting the appropriate remediation technology is imperative.
Such decisions, however, should be predicated on sound information about the site and some initial
information about the individual remediation processes. Information on the site can be obtained
from the initial site characterization. Information about the remediation process can be obtained
from published literature as well as from simple laboratory feasibility studies. The purpose of this
presentation is to describe what information should be collected during the initial site
characterization to evaluate bioremediation processes and also to describe some simple feasibility
studies that can be used to assist in the selection process.
At all sites, an initial site investigation is conducted to establish the identity of chemicals at
the site, determine the nature and extent of the contamination, obtain a description of the
environmental characteristics of the site, and make an initial appraisal of the appropriate
remediation technologies. This information is used to determine if the site is hazardous and, if
necessary, what action should be taken to reduce the hazards to a safe level. The amount of
information required to make these decisions is significant. This presentation and these handouts
emphasize only the information that is required to evaluate bioremediation.
4-1
-------
The first step is to define the problem and identify the types of contaminants. The physical
and chemical properties of the compounds that can influence biodegradation are identified and the
literature is assessed for information concerning the degradation of the compounds.
A second area of activity involves determining the distribution of the chemicals within the
site. Examples of specific analytical procedures are presented in Appendix A. In this stage, the site
is divided into a series of subsites for further evaluation. Compound concentration becomes
important at this point, because concentrations might be toxic and some pretreatment might be
required before bioremediation can be considered. Pretreatment might consist of dilution of the
contaminated area, for example, by mixing of wastes.
A third area involves characterization of the contaminated environment. This characteriza-
tion extends from gross characteristics such as soil, sediment, water, or subsurface material to more
specific characteristics such as permeability, redox conditions, pH, and hydrology. The microbio-
logical characteristics of the different environments also are identified. For example, anaerobic
bacteria would predominate in sediments whereas aerobic organisms would predominate in
unsaturated soils.
In a fourth area, any adjustment of the environment that might be required to permit
bioremediation is addressed directly. Such adjustments could include altering pH, prerenioving toxic
metals, and changing moisture content. In some cases, bioremediation might not be judged as a
possible option because the environment cannot be adjusted.
A fifth area involves evaluation of the microbiological needs pf the site. In this area, the
concern becomes the availability of nutrients, the potential additions of bacteria with specific
degradative characteristics, and whether the process should be conducted under anaerobic or aerobic
conditions. . , •
In a sixth area, a feasibility study is designed to test-potential bioremediation scenarios.
REFERENCES
Crip, C.R., W.W. Walker, P.H. Pritchard, and A.W. Bourquin. 1987. A shake-flask test for
estimation of biodegradability of toxic organic substances in the aquatic environment. Ecotox.
Environ. Safety 14:239-251.
Grady, C.P.L., J.S. Dang, D.M. Harvey, A. Jobbagy, X.-L. Wang, and H.H. Tabak. 1988. Protocol
for determination of biodegradation kinetics through the use of electrolytic respirometry. Presented
at the 14th Biennial Conference of International Association on Water Pollution Research and
Control, Brighton, England, July 17-23, 1988. (Published July 1989 in the Water Science and
Technology Journal.)
Grady, C.P.L., J.S. Dang, D.M. Harvey, A. Jobbagy, and H.H. Tabak. 1988. Protocol for evaluation
of biodegradation kinetics with respirometric data. Presented at the 61st Annual Conference of the
Water Pollution Control Federation, October 2-6,1988, Dallas, Texas. (Submitted for publication
October 1988, to the Journal of Water Pollution Control Federation.)
Iversen, N. and T.H. Blackburn. 1981. Seasonal rates of methane oxidation in anoxic marine
sediments. Applied and Environmental Microbiology 41:1295-1300.
4-2
-------
Kirsch, EJ., C.P.L. Grady, Jr., R.F. Wukasch, and H.H. Tabak. 1986. Protocol development for
the prediction of the fate of organic priority pollutants in biological wastewater treatment systems.
Aerobic and anaerobic multi-level biodegradability testing protocols. U.S. EPA, Water Engineering
Research Laboratory, AWBERC, ORD, Cincinnati, OH. EPA/600/S2-85/141.
Nelson, R.D. and J.G. Zeikus. 1974. Rapid method for the radioisotopic analysis of gaseous end
products of anaerobic metabolism. Applied Microbiology 28:258-261.
Owen, W.F. et al. 1979. Bioassay for monitoring biochemical methane potential anaerobic toxicity
Water Res. 13:485-492.
Rudd, J.W., R.D. Hamilton, and N.E.R. Campbell. 1974. Measurement of microbial oxidation of
methane in lake water. Limnology and Oceanography 19:519-524.
Shelton, D.R. and J.M. Tiedje. 1984. General method for determining anaerobic biodegradation
potential. Applied and Environmental Microbiology 47:853-857.
Suflita, J.M. and F. Concannon. 1991. The anaerobic decomposition of benzene in anoxic aquifer
slurries. Final Report to the American Petroleum Institute.
Swallow, K.C., N.S. Shifrin, and PJ. Doherty. 1988. Hazardous organic compound analysis.
Environ. Sci. Technol. 22:136-142.
Symons, G.E. and A.M. Buswell. 1933. The methane fermentation of carbohydrates. Journal of
the American Chemical Society 55:2028-2037.
Tabak, H.H. 1986. Assessment of bioaugmentation technology and evaluation studies on
bioaugmentation products. In: Proceedings of the Tenth United States/Japan Conference on Sewage
Treatment and NATO/Committee on the Challenges of Modern Society (NATO/CCMS) Conference
on Sewage Treatment Technology, Volume I, Part B. United States Papers p. 431-499. EPA/600/9-
86/015b, NTIS PB87-110631.
Tabak, H.H., R. Govind, S. Desai, and C.P.L. Grady. 1988. Protocol for the determination of
biodegradability and biodegradation kinetics of toxic organic compounds with the use of electrolytic
respirometry. Presented at the 61st Annual Conference of Water Pollution Control Federation,
October 2-6,1988, Dallas, Texas. (Submitted for publication in December 1988 to the Journal of
Water Pollution Control Federation.)
U.S. EPA. 1988. U.S. Environmental Protection Agency. RCRA correction action plan: interim
final. Office of Solid Waste and Emergency Response. EPA/530-SW-88-028. Washington, DC.
June.
U.S. EPA. 1988. U.S. Environmental Protection Agency. 795.54 Anaerobic microbiological
transformation rate data for chemicals in the subsurface environment. Federal Register
53(115)22320-22323. June.
U.S. EPA. 1988. U.S. Environmental Protection Agency. RCRA corrective action interim
measurements guidance: interim final. Office of Solid Waste and Emergency Response. EPA-530-
SW-88-029. Washington, DC. June.
4-3
-------
U.S. EPA. 1988. U.S. Environmental Protection Agency. Interim protocol for determining the
aerobic degradation of hazardous organic chemicals in soil. Biosystems Technology Development
Program, U.S. EPA. September.
U.S. EPA. 1986. U.S. Environmental Protection Agency. Test methods for evaluating solid waste.
Volume 1 A: Laboratory manual physical/chemical methods, Third Edition. Office of Solid Waste
and Emergency Response. Washington, DC. November.
U.S. EPA. 1986. U.S. Environmental Protection Agency. Test methods for evaluating solid waste.
Volume IB: Laboratory manual physical/chemical methods, Third Edition. Office of Solid Waste
and Emergency Response. Washington, DC. November.
U.S. EPA. 1986. U.S. Environmental Protection Agency. Test methods for evaluating solid waste.
Volume 1C: Laboratory manual physical/chemical methods, Third Edition. Office of Solid Waste
and Emergency Response. Washington, DC. November.
U.S. EPA. 1982. U.S. Environmental Protection Agency. Pesticide assessment guidelines
subdivision N chemistry: environmental fate. Office of Pesticides and Toxic Substances, U.S. EPA,
Washington, DC. October.
U.S. EPA. 1980. U.S. Environmental Protection Agency. Guidelines and specifications for
preparing quality assurance program plans. Office of Monitoring Systems and Quality Assurance,
ORD. QAMS-004/80, Washington, DC. September.
U.S. EPA. 1980. U.S. Environmental Protection Agency. Interim guidelines and specifications for
preparing quality assurance program plans. Office of Monitoring Systems and Quality Assurance,
ORD. QAMS-005/80, Washington, DC. December 29.
Ward, D.M. and G.J. Olson. 1980. Terminal processes in the anaerobic degradation of an algal-
bacterial mat in a high-sulfate hot spring. Applied and Environmental Microbiology 40:67-74.
Young, J.C. and H.H. Tabak. 1989. Screening protocol for assessing toxicity of organic chemicals
to anaerobic treatment processes (multi-step screening anaerobic inhibition protocol). Presented at
the AWMA/EPAInternational Symposium on Hazardous Waste Treatment: Biosystems for Pollution
Control, February 20-23, Cincinnati, OH. Air & Waste Management Association Journal.
4-4
-------
APPENDIX A
CHEMICAL ANALYSIS OF TEST CHEMICALS AND/OR WASTE SAMPLES
The selection of a suitable extraction procedure for a given combination of analyte(s) and
soil matrix generally requires some method development (Coover et al., 1987). For example,
methods that successfully recover a compound from one medium might not adequately recover the
same chemical from similar media (Albro, 1979). Also, extraction recoveries from a given set of
structurally similar media might vary (Albro, 1979).
Where possible, it is recommended that the existing and established analytical methods
described in Test Methods for Evaluating Solid Waste (USEPA SW-846 3rd Edition November
1986) be used.
The recommended SW-846 methodology for selected analytes are:
Gas Phase Volatiles
Method 0010 Modified Method 5 Sampling Train
Method 0020 Source Assessment Sampling System (SSAS)
Method 0030 Volatile Organic Sampling Train (VOST)
Method 5040 Protocol for Analysis of Sorbent Cartridges from Volatile Organic Sampling
Train.
Method 5030
Method 8010
Method 8015
Method 8020
Method 8030
Method 8040
Method 8060
Method 8080
Method 8090
Method 8100
Method 8120
Method 8140
Method 8150
Soil Phase Volatiles
Purge and Trap
Halogenated Volatile Organics
Nonhalogenated Volatile Organics
Aromatic Volatile Organics
Acrolein, Acrylonitrile, Acetonitrile
Selected Nonvolatiles
Phenols
Phthalate Esters
Organic Pesticides and PCBs
Nitroaromatics
Polynuclear Aromatic Hydrocarbons
Chlorinated Hydrocarbons
Organophosphorous Pesticides
Chlorinated Herbicides
Recommended extraction/concentration techniques (soils and sediments) are:
Method 3540
Method 3550
Soxhlet Extraction
Sonication Extraction
4-5
-------
Other published methods for Soxhlet extraction (Anderson et al., 1985; Bpssert et al., 1984;
Coover et al., 1987; Eiceman et al., 1986; Kjolholt, 1985; Grimalt et al., 1986), sonication extraction
(de Leevw et al., 1986; Sims, 1982) and homogenization and extraction (Coover et al., 1987; Fowlie
and Bulman, 1986; Lopez-Avila et al., 1983; Sims, 1982; Stott and Tabatabai, 1983; and U.S. EPA,
1982a) and extraction of materials from treatability studies (Brunner et al., 1985; Russell and
McDuffie, 1983) are available for reference and special applications.
Soil spiking and recovery studies should be conducted to determine the effects of soil, test
substance(s), and soil test substance(s) matrix on chemical extraction and recovery efficiency. Soil
samples should be sterilized using a method such as mercuric chloride, causing minimal change in.
soil physical and chemical properties (Fowlie and Bulman, 1986). The sterile soil should be spiked
with the test substance(s) to achieve a range of initial oil concentrations (Coover et al., 1987). The
range of concentration should include the highest concentration and less than one-half of the lowest
initial concentration to be used in degradation evaluations. Extractions of the soil/test-substance(s)
mixtures using the selected procedure will allow the evaluation of the effect of test substance(s) soil
concentrations on recovery efficiency. The effect of soil concentration was evaluated and found to
be significant for anthracene and benzo(a)pyrene by Fowlie and Bulman (1986).
Extracts of the soil and complex wastes should be spiked with test substance(s) of interest
to evaluate the effect of these matrices on chemical identification and quantification. Interferences
due to the extract matrix might be identified. Extraction procedures or instrumentation used for
identification and quantification then can be changed if necessary.
Standard curves should be prepared using primary standards of the test substance(s), or
chemicals in the test substance(s), dissolved in a suitable solvent that does not interfere with
chemical identification and quantification. Standard curves should be generated using at least six
points ranging from the highest concentration anticipated to the detection limit for the chemical.
REFERENCES
Albro,P.W. 1979. Problems in analytical methodology: sampling, handling, extraction, and cleanup.
Ann. N.Y. Acad. Sci. 320:19-27.
Anderson, J.W., G.H. Herman, D.R. Theilen, and A.F. Weston. 1985. Method verification for
determination of tetrachlorodibenzodioxin in soil. Chemosphere 14:1115-1126.
Bossert, I., W.M. Kachel, and R. Bartha. 1984. Fate of hydrocarbons during oil sludge disposal in
soil. Applied and Environmental Micro. 47:763-767.
Brunner, W., F.H. Sutherland, and D.D. Focht. 1985. Enhanced biodegradation of polychlorinated
biphenyls in soil by analog enrichment and bacterial inoculation. J. Environ. Qual. 14:324-328.
Coover, M.P., R.C. Sims, and W J. Doucette. 1987. Extraction of polycyclic aromatic hydrocarbons
from spiked soil. J. Assoc. Off. Anal. Chem. 70(6): 1018-1020.
de Leevw, J.W.E., W.B. de Leer, J.S.S. Damste, and PJ.W. Schuyl. 1986. Screening of
anthropogenic compounds in polluted sediments and soils by flash evaporation/pyrolysis gas
chromatography-mass spectrometry. Anal. Chem. 58:1852-1857.
4-6
-------
Eiceman, G.A., B. Davani, and J. Ingram. 1986. Depth profiles for hydrocarbons and polycyclic
aromatic hydrocarbons in soil beneath waste disposal pits from natural gas production. J. Environ
Sci. Technol. 20:500-514.
Federal Register. 1979. 44(53):167-16280 (Friday, March 16).
Fowlie, PJ.A., and T.L. Bulman. 1986. Extraction of anthracene and benzo(a)pyrene from soil.
Anal. Chem. 58-721-723.
Grimalt, J., C. Marfil, and J. Albaiges. 1986. Analysis of hydrocarbons in aquatic sediments. Int.
J. Environ. Anal. Chem. 18:183-194.
Kjolholt, J. 1985. Determination of trace amounts of organophorous pesticides and related
compounds in soils and sediments using capillary gas chromatography and a nitrogen-phosphorus
detector. Journal of Chrom. 325:231-238.
Lopez-Avila, V., R. Northcutt, J. Onstot, M. Wickham, and S. Billets. 1983. Determination of 51
priority organic compounds after extraction from standard reference materials. Anal. Chem. 55:881-
889.
Russell, D.J., and B. McDuffie. 1983. Analysis for phthalate esters in environmental samples:
separation from PCBs and pesticides using dual column liquid chromatography. Int. J. Environ
Anal. Chem. 15:165-183.
Sims, R.C. 1982. Land application design criteria for recalcitrant and toxic organic compounds in
fossil fuel wastes. Ph.D. dissertation. North Carolina State University, Raleigh, NC.
Sims, R.C., D.L. Sorensen, WJ. Doucette, and L. Hastings. 1986. Waste/soil treatability studies for
hazardous wastes: methodologies and results. Vols. 1 and 2. U.S. Environmental Protection
Agency, Robert S. Kerr Environmental Research Laboratory, Ada, OK. EPA/6~/6-86/003a and b.
NTIS No. PB87-111738.
Stott, D.E. and M.A. Tabatabai. 1985. Identification of phospholipids in soils and sewage sludges
by high-performance liquid chromatography. J. Environ. Qual. 14:107-110.
4-7
-------
Treatability
Studies
John Rogers
Athens Environmental Research Laboratory
U.S. Environmental Protection Agency
Athens, GA
MINIMUM REQUIREMENTS FOR QA/QC
Project description
Project organization
QA objectives
Sample custody
Internal QC checks
Performance and system audits
Preventative maintenance schedule
MINIMUM REQUIREMENTS FOR QA/QC
(Continued)
* Data assessment procedures
• Corrective actions
• QA reports
• Sampling plan
4-8
-------
DOCUMENTATION REQUIREMENTS FOR QA
• Accepted sampling techniques
* Field actions contrary to QAPP
• All pre-field activities
• QC for field measurement data
• Field activities
• Post-field activities
• Quality control samples
(generation & use)
QA FOR ANALYTICAL PROCEDURES
• Duplicate spike
• Reagent blank
• Documentation of fill samples
* Analytical procedures for surrogate
compounds
• Recovery efficiency for columns
• Detection limits and data reduction
OA FOR ANALYTICAL PROCEDURES
(Continued)
• Internal QC checks
• Performance and system audits
• Equipment calibration
• Extraction and sample preparation
procedures
4-9
-------
SITE CHARACTERIZATION
• Description of facility
• Identification of contaminants
• Extent of contamination
DESCRIPTION OF FACILITY
• Geographic location; property lines.
topography and surface drainage
* Infrastructure present
• Description of hazardous waste treatment.
storage, disposal and spill areas
* Surrounding land uses
• Production and groundwater monitoring wells
IDENTIFICATION OF CONTAMINANTS
• Organic/inorganic
• Chemical classes (metals.
halogenated volatiles.
pesticides)
• Mixtures
4-10
-------
INITIAL MATERIAL CHARACTERIZATION
• Organics: GC or GC/MS. HPLC
* Group analysis: priority pollutants.
fuels analysis, EP-Toxicity
• Metals: AA. ICP
• General chemistry: TOO. COD. BOD.
TPH. Oil & Grease (IR or GC).
TKN. N03. TP. P04. S04
• Optional radioisotope analysis: isotopically
labeled substrate studies.1
GENERAL CHEMISTRY
Analysis
Total Organic Carbon
-------
GROUP MULYSES
Analysis
Priority Pollutants
Add/Base Neutrals (37)
Volatile Organic Analysis (31)
Pesticides 1 PCBs (28)
Hetils (13)
Cyanides
Phenols
EP-ToxIclty
Simple Prep and Extraction
Httals
(Ag, As. Ba. Cd. Hg. Pb. Se)
Herbicides and Pesticides
(2.4-0. 2.4.5-TP. Endrln. Undane.
Hethoxy Chlor, Toxaphane)
Fuels Analysis
BTX (Benzene. Toluene, Xylene)
EOS (Ethyl DlbroMlde)
Titraethyl Lead (total)
Characterization of Fuels by
GC (Casollnt and Diesel)
Price Per Sample
Hater Solids
1195 1295
450
450
90
100
35
110
100
120
35
130
Method of Analysts
Graphite Fernanee
MS
Hrfrtde
Cold Vasor
ICT Kultl Cl(Mnt Analysis
(Ag, A1. 8. Ba, St. Ca. Cd
Cd. Cr, Of. Fe. C. Hg. Hn.
Ha. Hi, HI. Pb. St. SI. Sn
Tl. V. in)
1-12 ElHMHtl
11-24 Elmnts
Saaole Priplratlofl
Hatir
Ssll/Katir/Sludgi
CT-Tox Eitractlm
Croup Httal Analyili
Priority Pollutant IHUli
(Ag. At. Ba. Cd. Cr. Co. Hg
HI. n. Se. St. 71, Zn)
KM Kttall AMlytlt
(Ag. Al, Bi. Cd. Cr. Hj. Ft. Si)
Xaiareom Submit Llitid Hitali (Hon OP)
(Ag. Al. Al. Ba. ««. a. Cd. Co. Cr.
CU. Fl. Hg. K. Hg. Hn. Na. KK Pt. Sb.
St. II. V. Za
Price Per Element
13
30
Price Per Sample
Price Per Sanple
14
20
95
Price Per Sample
Hater Solid!
in 199
130
200
130
21S
EXTENT OF CONTAMINATION
• Groundwater
Plume size and movement
Contaminant concentration profiles
• Soil contamination
Distribution and concentration
• Surface water contamination
Horizontal and vertical distribution
• Sediment contamination
Horizontal and vertical distribution
4-12
-------
PROPERTIES OF CONTAMINANTS
Physical/ Chemical Characteristics
• Solid, liquid or gas
• Powder, oily sludge
• Acid. base, valence or
oxidation state
• Molecular weight
• Density
• Boiling point
PROPERTIES OF CONTAMINANTS
Physical/Chemical Characteristics
(Continued)
• Viscosity
• Solubility in water
• Cohesiveness
• Vapor pressure
• Flash point
PROPERTIES OF CONTAMINANTS
Safety Considerations
• Toxicity (human, microorganisms)
• Flammability
• Reactivity
• Corrosiveness
• Oxidizing or reducing
characteristics
4-13
-------
PROPERTIES OF CONTAMINANTS
Environmental Fate Characteristics
* Sorption
• Biodegradability
• Photodegradability
• Hydrolysis
• Chemical transformation
ENVIRONMENTAL CHARACTERISTICS
OF THE SITE
Qroundwater
* Flow characteristics
• Hydrogeological units
• Water level and movement
• Man-made influences
ENVIRONMENTAL CHARACTERISTICS OF THE SITE
Surface Water And Sediments
• Physical characteristics (location.
velocity, depth, surface area, etc.)
• Seasonal fluctuations
• Temperature stratification
• Flooding tendencies'
• Drainage patterns
• Evapotranspiration
• End use of water
4-14
-------
ENVIRONMENTAL CHARACTERISTICS
OF THE SITE
Water/Sediment Chemistry
• pH
• Total dissolved solids
• Biological oxygen demand
• Alkalinity
• Conductivity
ENVIRONMENTAL CHARACTERISTICS
OF THE SITE
Water/Sediment Chemistry
(Continued)
• Dissolved oxygen profiles
• Nutrients NHs. N03/N0t_.
• Chemical oxygen demand
• Total organic carbon
ENVIRONMENTAL CHARACTERISTICS
OF THE SITE
Distribution And Soil Structure
* SCS soil classification
• Surface soil distribution
• Soil profile ASTM classification
* Depth to water table
4-15
-------
ENVIRONMENTAL
CHARACTERISTICS OF THE SITE
Physical Characteristics Of Soils
* Hydraulic conductivity
• Relative permeability
• Bulk density
• Porosity
• Particle size distribution
• Moisture content
• Infiltration
• Vertical flow
ENVIRONMENTAL
CHARACTERISTICS OF THE SITE
Chemical Characteristics Of Soils
• Soil stratigraphy
• Soil sorptive capacity
• Ion exchange capacity
• Soil organic content
• Soil pH
• Mineral content
TREATABILITY PROTOCOLS
Properties Assessed
Biodegradability of contaminants
—aerobic
—anaerobic
Effectiveness of nutrient amendments
—inorganic supplements (N.P.S.)
—electron acceptors
—organic supplements
4-16
-------
TREATABILITY PROTOCOLS
Properties Assessed
(Continued)
• Effectiveness of inocuia
—cultures of natural organisms
—specific degraders
e Nondegradative losses
—volatilization
—sorption
—leaching
• Genotoxicity of the waste
PROTOCOL COMPONENTS
• Scope and approach
• Summary and method
• Collection and sampling of site materials
- sample selection
- sample collection
- sample characterization
- sample transportation
- sample preservation
- sample holding times
PROTOCOL COMPONENTS
(Continued)
• Apparatus and materials
- reactor components
- reactor design
* Procedures
- reactor setup
- reactor operation
- analysis of reactor contents
- reactor configurations
minimal treatment
intermediate treatments
complete treatment
4-17
-------
PROTOCOL COMPONENTS
(Continued)
Data recording and analysis
- data to be reported
- determination of degradation rates
References
- general
- chemical analysis
- sampling
REPRESENTATIVE FIELD SAMPLES REQUIRED
FOR BIOTREATABILITY STUDIES
• Evaluation of many samples to
obtain a bioactivity site matrix
* Field composite to define
any site bioactivity
* Field background samples essential
for material characterization
Centre)
(HeamendmenU)
Intermediate
Change pH
Maximal
• Ch«ng*pH
• Addnutrl.nU
• Add mlcrotrf infirm
• Mix
4-18
-------
CO
CO
o
3
O
Q.
O
O
Control
Maximal
Time
CO
at
o
_i
•o
c
3
O
O.
O
O
Control
Maximal
Time
EXPERIMENTAL DESIGN
• Controls: sterile, no treatment,
field background, number?
• Replicates: duplicate or triplicate?
all time points? all controls?
• Treatments: what are the questions
you want answered?
• How are you going to optimize
the degradation process?
4-19
-------
EXPERIMENTAL DESIGN
(Continued)
• Treatment time.- how long should
the study be performed?
* Types of analysis: bulk measurements?
waste specific?
* Data reduction.- raw data?
massaged data? QC/QA?
• Cost considerations: how will it
limit scope of test?
RELATIVE RATES OF REDUCTION AND OXDATON
. i
I
*
>
•
2 3
Numb.r of AtUch.d Chlorlnci
lnor««ilnj ExUnt of Hilog*n»tlon
fer M»th«n»«. Clhino, Eth«n«>
INCREASING NUMBER OF CHLjORINGS
•t«rll* e*nir«l
til H « H HI IIHIH »f »
ky A. Eulr*^hui Hi«0
4-20
-------
INCREASING NUMeeR OP CHLORINES
Sjy 4 -j
E s]
af *1
t** i
Sic I -I
?-"
INW N
IO SO 4O 90
TIMC W*.l
" 1 AUTOCLAVCO | « •- . •» I •
4 I W WIEKS A«| J V ."• V.*-
SO 40 SO
TIME <»IK.)
•i r, .» s-=-
' • -:^j >"
•I i sl.Jl.in.fr'..
REixcrn« ce>cciR»jATK)N OF
BY AN«F081C MICROORGANISMS FROM SEOIMCNTS
RELATIVE BKDDEGRADATION of POLYCYCLX5
AROMATIC HYDROCARBONS (PAH)
2 S
o s
2345
Numbtr ef Rlng*/PAH
Inercitlng Mol«oul.r W«lghl
D*er*i*ing Aqu*ou« tolublllly
* J
MICROBIOLOGICAL DEGRADATION
4-21
-------
FATE OF POLYNUCLEAR
CONTAMKfATES M CREOS
DURMG LAND TREA
4 Month Stud]
PNA Ctess % ReducHoq
2 Rkig Structure 90
(Naphthalene)
3 Rhg Structure 80
(Phenaphthalene)
4 Ring Structure 25
(Pyrene)
Total PNA 65
AROMATIC
OTE WASTE
TMENT
f
Half-Life
33 Days
47 Days
235 Days
100 Days ,
PHYSIOLOGICAL BARRIERS TO BIODE
-------
GENETIC BARKERS TO BIODEGRADAT1ON
* No genetic coding for
contaminant degradation
• No genetic codutg for
transport into eel
• Genetics for bfodegradation exist
but not indudbfe or
dfebursed on genome
* Low level of expression
BfODEGRADATION
Requires
• Suitable electron acceptor
• Organic substrate
• Nutrients: nitrogen,
phosphorous, others
• Trace metals
BIODEGRADATION OF 20 ppm
PCP IN SOIL UNDER
LABORATORY CONDITIONS
PERCENT 40
PCP
REMOVED
FROM SOIL 60
80
100
DAY
4-23
-------
MICROBIAL EVALUATION
Reduction of Contaminants During a 4-Week
Incubation of Nutrient Amended Site Samples
Saturated
Soil
A
COST BREAKDOWN CASE # 1
17
X 2
34
X . 2
68
X $450
$30,600
+ 4,000
Field Samples
Replicates
Sample Times (0, 4 weeks)
Samples for Analysis
GC/MS BNA
Analytical Costs
Materials/ Labor for Set up
V
,.. ?34-6,00 Total Cost (est)*
Note: No Administrative Charges; Data Evaluation;
Report Preparation; QA/QC
BKWEMCDiATIOH OF CREOSOTE/PCP
Contaminated Sols (Slurry) Case Study »2
01 ma pew mo/kg (touunfc!
SO
4-24
-------
BIOREMEDIATION OF CR1OSOTE/PCP
Contaminated Sols (Slurry) Case Study 82
mg/Kg 3d
500
CASE STUDY # 2
1 Single Soil Sample
3 Repficates
x2 Treatments (Active Amended/Control)
6
x4 Sample Times (0,2,6,8 wks)
24 Samples 6
$ 40 Oi/Gfease (T.R.) x3 (0.4.8 wks)
$960 18 Sampfes
x$450 GC/MS(BNA)
$8100
$960 <• $8100 = $9060 Analytical Costs
for Experimental Section Initial Material
Characterization: TOC, TKN, O-PO4, NOa, NH3
CASE STUDY #
(continued)
170
x 2 Repicates
$340
$9,400
$4,500
Total Analytical Costs
Labor/Materials
$13,900 Total Cost of Treatabifty*
* Note: No administrative charges; data
evaluation, report preparation, QC/OA.
4-25
-------
EFFECT OF SLURRY TREATMENT ON PAH AND
PCP CONCENTRATIONS8 IN CREOSOTE/PCP
CONTAMINATED SOILS
Initial
Concentration 4 Weeks
Compound (mg/kg) (mg/kg)
Acenaphthene
Acenaphthalene
Dibenzofuran
Fluorene
Fluoranthene
Anthracene
80±12
3.4±0.1
17±3
37±6
167±38
30±3.5
3.8W
0.8±0.1
3.8W
3.8W
3.9±0.8
2.2±0.6
8 Weeks
(mgfag)
3.8W
2.1 J
3.8W
3.8W
3.6±0.3
6.7±1.2
* Average of triplicate arulysl* ± variance.
"Undetected at the noted concentration.
J Eillmated concentration. Sample data was leas than the quantHatlon IlmK but greater than zero.
EFFECT OF SLURRY TREATMENT ON PAH AND
PCP CONCENTRATIONS8 IN CREOSOTE/PCP
CONTAMINATED SOILS (Continued)
Initial
Concentration 4 Weeks 8 Weeks
Compound (mg/kg) (mg/kg) (mg/kg)
Phenanthrene
Pyrene
Chrysene
Benzo[a]anthracene
Benzo[a]pyrene
Pentachlorophenol
130±17 0.5±0.1 0.7±0.1
177±38 26±18 10.6±1.5
40±3 5.9±1.1 3.5J
34±3 1.7±0.2 1.9±0.2
19±1.3 9.8±1.3 10.6±2.1
127±12 24±2.0 31.6±5.0
"Undetected at trte noted concentration.
J Estimated concentration. Sample data waa less than the quantttatlon Ilmtt but greater than zero.
PARAMETERS MOMTORED DURING
THE PILOT TEST OPERATION
Parameter
Soi temperature
Sol pH
54 F to 82 F
7.0 to 8.9
Soi moisture content 11% to 14% by weight
V J
4-26
-------
TOTAL OIL AND OtEASC CONCCNTRATIONS IN SOIL MCtOCOSMS (i^/kg)
SappU
CONTROL 1
2
3
Av.r.g.
Standard Oivlalton
5* LOADING RATE 1
2
3
Av*rag«
Standird Deviation
5* LOADING RATE ANO
MUTRItHT-ADJUSTEO I
2
3
A**r*g«
Standard DtvUtton
SX LOADING UTC.
HUTXIHT-AD3USTEO 1
AHO INOCULATED 2
3
Standard OcvUtlon
1« LOADING RATE 1
2
3
A*.rag«
Standard 0*vUtt«i
o
510.000
470.000
460.000
400,000
26,454
31.000
31.000
26,000
30,667
4.041
38,000
43. COO
22.000
34.331
10.970
22.000
26,000
26.000
25,311
3,055
47.000
66,000
46,000
53,000
11.269
V*
410.000
440.000
450,000
4J3.333
20,817
34.000
26.000
11,000
30.33)
4,041
18.000
19.000
15,000
17.667
1.52S
26,000
26,000
59.000
37.000
19,053
47.000
87.009
56,000
63.333
Z0.984
ik
510,000
SSO.OOO
510.000
U1.333
23,094
35.000
18.000
34,000
32,311
3.78C
18.000
IS.OOO
22.000
19,333
2,309
37.000
29.000
2I.OOQ
29,000
8.000
41.000
43.000
48.000
44,000
3.606
_a '
530,000
510.0
-------
-------
SCALE-UP AND DESIGN ISSUES AND CLEANUP OBJECTIVES
Ronald J. Hicks
Groundwater Technology, Inc.
Concord, CA
INTRODUCTION
Bioremediation is gaining national and international recognition as a viable treatment
technology for remediating contaminated soils and ground water. Increasingly, regulatory agencies
at the federal, state, and local level are encouraging the use of this technology. The popularity of
bioremediation primarily is due to the potential advantages it offers over traditional treatment
technologies such as pump and treat, excavation and disposal, or excavation and incineration.
Bioremediation, however, is not a panacea for solving all of our society's environmental
problems. The selection and successful implementation of bioremediation is site specific and depends
on a number of physicochemical, hydrogeologjcal, and microbiological factors that determine, not
only the efficacy of the technology (i.e., the capacity to bring about the desired change), but also its
applicability.
The essence of Total Quality Management is to ensure that the right activity is performed
in the right way. Translating this approach to bioremediation (or any remediation technology) means
first selecting the proper technology and, second, ensuring that the chosen technology is installed
properly.
DOING THE RIGHT THING
The key issues in determining the right thing to do are (1) understanding completely the
problem to be addressed, (2) defining the goals, and (3) selecting the proper technology.
Understanding the problem requires a thorough assessment of the site, in terms of its
physical, chemical, and microbiological properties; the contaminant, in terms of its mass and
treatability; public health and safety issues; and regulatory issues. Defining the goals of remediation
in terms of cleanup levels as well as cost and time constraints is essential in properly selecting the
technology most appropriate to the site.
5-1
-------
Selecting the most appropriate technology for a given site depends primarily on issues of
mobility and reactivity.
Mobility refers not only to the chemical, physical, and hydrogeological properties governing
the transport of the contaminant, nutrients, and/or oxygen, but also the site conditions and regulatory
factors that can affect the movement of the contaminated matrix.
Reactivity refers not only to the biodegradability of the contaminant but also to the
interactions between the physical and chemical features of the environment and the contaminant or
proposed amendments.
DOING THINGS RIGHT
Once bioremediation has been selected based on feasibility, and a determination of the
appropriate bioremediation option has been made, the project manager or operator needs to gather
site information relative to the design and implementation of the chosen bioremediation option.
The principal informational needs for design and implementation are those that relate to (1)
control of contaminants, (2) mass transport of amendments, (3) monitoring system performance and
success, (4) treatment of by-products, and (5) closure of the site.
Control of Contaminant
Gaining hydraulic control of the site to reduce or eliminate migration of the contaminant is
necessary for all remediation options where ground water is the contaminated matrix. It is
particularly important, however, for in situ bioremediation because of the need to control both the
contaminant and amendments to keep both in the zone of treatment.
Mass Transport of Amendments
Inmost situations, the design and successful implementation of bioremediation is limited by
the mass transfer of nutrients and oxygen. Although contaminant concentration is often the only
information available, it is essential to determine the approximate mass of the contaminant that is
present at the site. One needs to remember that it is a total mass of contaminant that is being
remediated, not a concentration. Mass of contaminant is necessary to calculate the length of time
required to remediate the site, the total nutrient and oxygen load that will be required, and the costs
of remediation. In addition, mass balance of contaminant is probably the best indicator of when a
site is near closure.
For bioremediation, not only is the mass of the particular contaminant important, but also
the mass of total utilizable organic carbon present. The total mass of utilizable organic carbon
ultimately will determine nutrient and oxygen requirements and time of remediation. In unsaturated
soils, oxygen toost often is supplied by either positive or negative induction of air. For most soil
types, this can be accomplished via vapor extraction systems. These systems were designed primarily
for the extraction of volatile hydrocarbons; they are extremely effective in supplying oxygen for
aerobic biodegradation, however, and often are used for that purpose exclusively. By monitoring
carbon dioxide evolution from these systems, increased biological activity can be demonstrated.
5-2
-------
Soil permeability is an important determinant of whether or not in situ bioremediation is
applicable or if excavation and aboveground treatment is necessary. Low permeabilities generally
indicate that the mass transfer of both oxygen and nutrients might be severely impeded and, thus,
aboveground bioremediation, in either reactors or biopiles, might be more applicable than in situ
bioremediation.
The mass transfer of inorganic nutrients in unsaturated environments usually is accomplished
by infiltration of nutrient solutions through the soil. The main limitations to supplying nutrients in
this manner are the depth to which the nutrients need to penetrate and the adsorptive capacity of
the soil for the nutrients. If the addition of inorganic nutrients in solution form is deemed
inappropriate for the particular site, then alternatives, such as supplying the nutrients in a gaseous
form, might be more conducive to bioremediation.
As with unsaturated systems, the mass transfer of inorganic nutrients in saturated systems
is limited by the adsorptive capacity of the solid matrix. In addition, the hydraulic conductivity might
limit the rate of transfer of inorganic nutrients. Finally, the addition of nutrients might adversely
affect the hydraulic conductivity of the aquifer through precipitation.
During the design of bioremediation, one must determine the required permits that must be
obtained to operate the system.
Monitoring
Design information needed for monitoring includes that related primarily to regulatory
compliance and system operation. During the design phase, one needs to determine what
information will be required by local, state, and/or federal regulations to determine if remediation
is being achieved.
In addition, it is essential that information be obtained to determine if the system is
operating effectively. For bioremediation, information such as background carbon dioxide levels and
carbon dioxide evolution during operation can be used to determine if the system is operating
properly. Another parameter that might be useful is the microbial population levels.
Treatment of By-Products
If by-products, either off-gases or soluble metabolites, are to be produced, information
relevant to their treatment must be obtained prior to implementation. Off-gases can be treated via
carbon adsorption, catalytic oxidation, or vapor-phase bioreactors. Soluble metabolites often can be
treated in the same manner.
Closure
Information relevant to closure includes the closure levels that will be required, final
disposition of soils or treated water, risk assessment requirements, disposition of equipment, and
post-closure monitoring requirements.
Bioremediation can be a very effective method for treating soils and ground water
contaminated with organic wastes. It has many advantages over traditional treatment technologies
including lower costs, complete destruction of the contaminant, and shorter time to remediate. It
is a very site-specific technology, however, and requires a myriad of information to be successful.
5-3
-------
REFERENCES
Canter, L.W. and R.C. Knox. 1986. Groundwater Pollution Control. Lewis Publishers, Michigan.
Freeze, R.A. and J.A. Cherry. 1979. Groundwater. Prentice Hall, Inc., New Jersey.
Gibson, D.T. 1984. Microbial Degradation of Organic Compounds/Marcel Dekker, Inc., New York.
Heath, R.C. 1989. Basic Groundwater Hydrology. USGS #2220.
Hinchee, R.E. and R.F. Olfenbuttel. 1991. In Situ Bioreclamation: Applications and Investigations
for Hydrocarbon and Contaminated Sites. Butterworth-Heineman, Toronto.
Hinchee, R.E. and R.F. Olfenbuttel. 1991. On-Site Bioreclamation: Processes for Xenobiotic and
Hydrocarbon Treatment. Butterworth-Heineman, Toronto.
Howard et al. 1991. Handbook of Environmental Degradation Rates. Lewis Publishers, Michigan.
Knox et al. 1986. Aquifer Restoration. Noyes Publications, New Jersey.
Kostecki, P.T. and EJ. Calabrese. 1989. Petroleum Contaminated Soils, Vol 1-3. Lewis Publishers,
Michigan.
Nelson, C.H., RJ. Hicks, and S.D. Andrews. 1993. In situ bioremedation: an integrated approach.
In: J.H. Exner, and P.E. Flathman, eds., Bioremediation: Field Experience. Lewis Publishers,
Michigan. (In press.)
Nyer, E.K. 1985. Groundwater Treatment Technology. Van Nostrand Reinhold Company, Inc.,
New York.
Pitter, P. and J. Chudoba. 1990. Biodegradability of Organic Substances in the Aquatic Environment.
CRC Press, Florida.
U.S. EPA. 1983. U.S. Environmental Protection Agency. Guide for identifying cleanup alternatives
at hazardous waste sites and spills: biological treatment. EPA-600/3-83-063.
5-4
-------
Scale-Up and Design Issues
and Cleanup Objectives
•A Total Quality
Management Approach
Ronald J. Hicks
Groundwater Technology, Inc.
Concord, CA
Essence of Total Quality Management
"Doing the Right Thing-
the Right Way"
What
Is
Done
Wrong Things
Right
Wrong Things
Right
Wrong Things
Right.
Wrong Things
Right
Doing the Right Thing
Key Issues
•Problem Understanding
«Goal(s) Definition
•Technology Selection
5-5
-------
Doing the Right Thing
Understand the Problem
•Site
•Contaminant
•Public Health and Safety
•Regulatory Issues
Public Health and Safety Issues
Witt Bioremediation:
1. Remove or reduce risk associated
with contaminant?
2. Do so in a timely fashion and at a
reasonable cost?
3. Present any additional hazards?
• By-products
• Bio-hazards
Regulatory Issues
What are the regulations
pertaining to:
1. The contaminant?
2. The treatment process?
5-6
-------
Doing the Right Thing
Define Goals
• Cleanup objectives
• Cost objectives
•Time objectives
Selection
of
Remedial
Goals
• Impact
• Degree
• Exposure
• Hazard
• Area Impacted
• Location of Site
• Site Use
• Current
• Future
• Type
• Organic
• Inorganic
• Quantity
• Properties
• Solubility
• Volatility
• Reactivity
• Soils
• Permeability
• Porosity
• Homogeneity
• Depth of
Water
• Recharge
• Hydrogeology
'obstruction / fnvtrmanen
Spectrum of Response
Monitoring
Containment
Pump&
Treat
Extraction
Destruction
No Action No Residue
Effort - Complexity - Cost
Persistence - Liability
5-7
-------
Doing the Right Thing
Determining
Cleanup Standards
Risks
Cleanup
Standards
1
Effort
| Technology I
Closure Strategies
•Closure as a Point
•Closure as a Process
•Closure as a Limit
Closure as a Point
Analytical Results
MW-12 MW-17
BTEX 235 235
TPH 125 34
TCE 4 12
Cone
-
n
i — i
-
Goal
[\n
MW-12 MW-17
5-8
-------
Closure as a Process
•^~ ~~^-
/fX t S)\
Source
I/ 1 XJ
Onsite
Impact
Offsite
V^llLU.*-*^
V Impact J
Offsite
Impact
Reduce
Source
Onsite
Impact
I=3>
<>
1 *)
Time »-
Closure as a Limit
Cone.
Time-
Effort
Response
Hazard ^ Risk
Risk = /"(hazard, exposure)
5-9
-------
Risk-Driven Remediation
•Ensures cleanup to
acceptable levels based on
health and environmental
criteria, without excessive
costs
•Provides site-specific
recommendations
Doing the Right Thing
Technology Selection
In Situ
Bioventing Bioreactors
Slurry Reactors Composting
Bioreactors Aboveground Biocells
Land Treatment
Remedial Effectiveness
• Mass Removal Rate
(Ib/unit time)
5-10
-------
Selecting a
Bioremediation Technology
Technology Selection
Based on:
1. Mobility of contaminant or
contaminated matrix
2. Reactivity
• Biological
• Chemical
• Photochemical
Technology Selection in
Bioremediation
High
Reactivity
Low
Contaminant Mobility
High Low
•Land Treatment
•Aboveground
Treatment Cells
•Bioreactors
•In Situ
• Bioreactors
w/Adapted
Population
•Slurry Reactors
•In Situ
Bioremediation
•Bioventing
• Fungal Treatment
•Biological
Stabilization
•Chemical/Biological
Treatment
Doing the Right Thing
Design and Implementation
Design parameters are technology-
specific, but are related primarily to:
• Control of contaminant
• Mass transport of amendments
• Monitoring performance and success
• Treatment of by-products
• Closure
5-11
-------
Informational Needs for
Control of Contaminant
(and Amendments)
• Position and thickness of aquifer
• Extent of contamination
• Transmissivity and storage
capacity of aquifer
• Hydraulic conductivity and
gradient
Informational Needs for
Control of Contaminant
(and Amendments)
• Aquifer boundaries with
pumping
• Climate information
• Soil texture and structure
• Topography
Informational Needs for
Mass Transport
• Mass of contaminant
• Air permeability
• Adsorptive capacity
• Hydraulic conductivity
• Reactivity of aquifer
sediments to amendments
5-12
-------
Feasibility Study
• Nutrients
• 10,50,100 ppm nutrient solution tested
• 10 ppm optimum with 62 percent petroleum
hydrocarbon removal in 11 days
• Soils
• Samples from 8-ft, 13-ft, and 18-ft zones
• lithology: Silt Sand-»-Coarse Sand-*-Gravel
Feasibility Study (com.)
Soil Hydraulic
Sample H2O2 Conductivity Nutrient Adsorption
Depth Reactivity Reduction PO4 NH4
8 feet 90% 80% 56% No change
13 feet 49% No change 86% 15%
18 feet 78% No change 74% 53%
Effect of Nutrient Addition on
Hydraulic Conductivity
Hydraulic
Conductivity
(Kon/s)
Time
5-13
-------
Informational Needs
for Monitoring
Performance and Success
Mass balance of contaminant
Rate and extent data
By-products expected
(e.g., CO2 production)
Closure levels
Microbial population/Ecology
Remediation Results
Process
Phase separated product recovery
Volatilization
BiodegradationA
Total
Mass
Removed
1,510 Ibs
780 Ibs
33,300 Ibs
35,590 Ibs
Total ground water recovered
and reinjected
Initial Contaminant Mass Estimate
8,835,598 gal
(>1S pore volumes)
25,800 Ibs
*£tthutcd from COj tawjureaitntt from the vapor extraction system effluent COj measurements
ww converted tato eonttmbiant BUM removal rates using the foBowfaa conservative assumptions,
L TVienty portent of the carbon dioxide was produced from the btodegradatlon of
fiittvc orstnlc nutter.
2. Forty percent of the blodcgnded, orzanlc cubon vru evolved as carbon dioxide.
iHi •in.CX.m.lt I'll. r tin ljlnn« 1l«».liirt»M»TH»«^iiKiiihl»y*»**»"'i«' >i Til
Correlation between Carbon Available and CO2
Produced \vith Vented Bioremediation System
Percent ,
CO2 In 8~
Blower e-
Exhaust
4—
2-
Carbon
4 2 4
-120 Vacuum
—110 Flnw
-100 riow,
-90 cftn
-1'200 Total
-1,000 caj^jj
-BOO vapors,
—600 ppm
—400 (Methane &
-200
ib 12
Weeks of Operation
5-14
-------
Rates of Biodegradation as a
Function of Product and Soil Type
Gravel
Medium Sand
Fine Sand
SiltySand
Silts & Clays
Gasoline
0 40 80 120 160 200 240
Days of Treatment
Achieving Target Levels and
Predicting Cleanup Times
Dependent on:
• Maximum rate and extent as
determined by treatability
study
• Rate at which amendments can
he added
• Ability to optimize system
Effect of Nutrient Addition on
Biodegradation
1,400
1,200
1,000
Gasoline, 80°
PPm 600
400
200
10 20 30 40
Days of Treatment
50
5-15
-------
Achieving Target Levels and
Predicting Cleanup Times
Amendments
O2IN, P
/\
Success of bioremediation is dependent
upon bringing together the organisms,
amendments, and the contaminant in
both space and time
Predicting Cleanup Times
• Treatability Data Not Always
Predictive
m Container effects
(reactor design)
• Nonrepresentative site
samples
• Highly optimized conditions
Predicting Cleanup Times
• Environmental
Factors
• Temperature
• Precipitation
5-16
-------
SN
Kinetic Illustration
Assumption:
Non-Steady-State System
Reaction Rate=ds/dt
dS/dt=KSt (equation 1)
K= Reaction constant
S = Reaction/substrate
t =Time
Modification of Equation
for Temperature Effect
ds/dt=A=K«%»f(St)
(equation 2)
A=Biological activity=f{T°, St)
% = Biomass
K=f(T°)
Predicting Cleanup Times
Statistically Valid Experimental Design
B Mean, standard deviation, coefficient of
variation
• Significant differences of means for
treatment effects
» Student's T-Test
» Analysis of variance
» Correlation and regression analysis
» Analysis of co-variance
5-17
-------
Predicting Cleanup Times
• Mathematical Models
• Lack of effort in
development
• Insufficient data
• Invalid assumptions
• Critical for scale-up
Predicting Cleanup Times
• Kinetic Rate Constants
m Half-life
• Michaelis Menten
• Reaction order
• Critical for modeling
Treatment of By-products
Vapors
• Carbon
• Catalytic oxidation
• Vapor phase bioreactors
» Compost
»Soil Bioremediation Cells
Soluble
• Carbon adsorption
• Retirculation
• Alteration of metabolic processes
(e.g., anaerobic/aerobic)
5-18
-------
life Cycle Design
Cone.
Time-
life Cycle Design
•Time effect on parameters
•Capital costs
• Operator expenses
Capital Equipment Costs
300
250
200
Daily
Costs ISO
$ 100
50
Assume:
$100,000 capital
equipment costs and
12% interest rate
01 2 345 6789 10
Time for Write-Off, Years
5-19
-------
Operational Expenses
Assume:
• $100,000 capital costs
• 10-year life of equipment
• 12% interest rate
• 15 hp for power ($0.06/kWh)
• $3/day chemical cost
• $10/hour for operator
Operational Expenses with
No Operator Attention
Chemicals 4%
Power 36%
Equipment 60%
Operational Expenses with
8 Hours/Day Operator Attention
I Chemicals 2%
I Power 18%
I Equipment 30%
I Operator 50%
« Ny«r, onundwlhr T»MhnM
5-20
-------
Operational Expenses with
24 Hours/Day Operator Attention
I Chemicals 1%
I Power 9%
I Equipment 15%
I Operator 75%
SOUTM: Hftt, anxlxjuitw TrMhlMU TKtHMtofly.
Operational Expenses Summary
400
300
Daily
Costs 200
$
100
10. 20
Man-Hours/Day
25
Operational Expenses with
$500,000 Capital Equipment and
24 Hours/Day Operator Attention
I Chemicals 2.3%
I Power 22.7%
I Equipment 37.5%
(Operator 37.5%
5-21
-------
Loss of Remedial Effectiveness
at End of Cleanup
o
Advective Flow
Good Extraction
Effective Treatment
Diffusive Flow
Poor Extraction
Limited Treatment
Optimizing Performance
Cone.
O Active Wen •Shut-In Well
Cone.
Time
Reconfigured
System
System [Reconfiguration
Time
Complex Problems Require
Integrated Solutions
i No silver bullets
i Complex problems are
combinations of simple
problems
> Complex solution is
integration of simple answers
5-22
-------
REACTORS FOR TREATMENT OF SOLID,
LIQUID, AND GASEOUS PHASES
Chris Nelson
Groundwater Technology, Inc.
Englewood, CO
and
Richard Brenner, John Glaser, and Paul McCauley
Risk Reduction Engineering Laboaratory
U.S. Environmental Protection Agency
Cincinnati, OH
Biological treatment is becoming standard technology for treating organic contaminants in
the environment. For aboveground treatment of contaminated ground water, bioreactors have the
advantage over mass transfer technologies such as air stripping or carbon absorption in that
biological action is capable of converting contaminants to innocuous end products such as carbon
dioxide and water. Other technologies capable of complete destruction, such as chemical oxidation
or incineration, tend to have higher operating costs. A wide range of chemicals can be treated cost
effectively by biological treatment in reactors.
Bioreactors utilizing fixed bacterial films are able to overcome many of the potential
problems faced in treating contaminated ground water. The biofilm is stable to a wide range of
fluctuating contaminant concentrations and mixtures encountered in ground water treatment. The
biofilm can withstand sudden high concentrations shocks and remain stable in the presence of very
low contaminant loadings. The bacteria attach to support media and provide a stable biomass within
the reactor. These reactors can be operated with a minimum of sludge formation. The stability of
the film allows long-term operation with minimal operator attention.
Bioreactor technology has been successfully implemented at a number of sites. Treatment
efficiency is dependent on correct sizing and evaluation of operational parameters. Removal rates
can be greater than 99 percent with proper design. Reactors capable of treating high levels of
contaminants also have been integrated with other forms of water treatment to yield highly effective
processes. Bioreactors are especially effective for the treatment of soluble contaminants, such as
phenol, acetone, or alcohols, which cannot be efficiently removed by air stripping or carbon
absorption. Reactors also can provide cost-effective alternatives for the treatment of volatile
6-1
-------
contaminants, such as benzene and toluene, when carbon loading is very high or off-gas treatment
is necessary.
• The biological treatment of soils and sludges represents a significant remedial tool. This
technology is widely used to treat soils under a wide range of conditions and for a wide range of
contaminants. Contaminants ranging from gasoline to heavy fuels, as well as plasticizers, coal tars,
creosotes, and various solvents, have been degraded successfully in soil piles. Soil conditions ranging
from sand and gravels to low permeable sludges have been treated successfully.
While the biological treatment of soils and sludges is a versatile tool, it is not without its
limitations. As a result, a proper understanding of this technology is necessary for its proper use.
This understanding involves both microbiological and engineering aspects. When properly designed
and operated, soil biological treatment is a cost-effective technology; when misapplied, it is a costly
pretreatment for disposal.
From the microbiological standpoint, it is important to understand the key process variables
and the limitations of the technology. The key process variables are those factors that influence the
rate and extent of biodegradation. From the engineering standpoint, the focus is on factors that
affect the integrity or the performance of the system. The three areas of concern are containment,
soil conditioning, and the type of aeration system.
REFERENCES
API. 1989. American Petroleum Institute. Soils impacted by petroleum hydrocarbons: a literature
review.
Alexander, M. 1985. Biodegradation of organic chemicals.. Envir. Sci. and Tech. 18: 106-111.
Atlas, R.M., ed., 1984. Petroleum Microbiology. McMillan Publishing.
Brown, R., and T. Hawke. 1992. The Biological Treatment of Soils and Sludges. Air and Waste
Management Association, Kansas City, MO.
Cartwright, R.T., et al. 1990. Biotreat sludges and soils. Hydrocarbon Processing pp. 93-96.
October.
Grady, C.D., and M.C. Lim. 1980. Biological Wastewater Treatment. Marcel Dekker, Inc.
Hawke, T., C. Nelson, and M. St-Cyr. 1992. Bioremediation treats contaminated soils in Canadian
winter. Oil and Gas Journal, November.
Hicks, R.J., et al. 1990. In situ bioremediation of petroleum hydrocarbons. Proceedings of WPCF
Symposium on In Situ Bioremediation of Groundwater and Contaminated Soils. Washington, DC,
October.
Kirk, T.K., et al. 1986. Oxidation of polycyclic aromatic hydrocarbons and dibenzo(p)dioxins by
Phanerochate chrysosporium. J. Biol. Chem. 261.
6-2
-------
Loahy, M., and D. Borowy. 1991. Use of aboveground bioreactors for the treatment of
contaminated groundwater. Presented at Hazmat South, 1991, Atlanta, GA.
Nyor, E. 1985. Groundwater Treatment Technology. Van Nostrand and Reinhold Publishers, 188
pp.
Raymond, R.L., et al. 1984. Oxygen transport in contaminated aquifers. NWWA, API Conference
on Petroleum Hydrocarbons and Organic Chemicals in Groundwater: Prevention, Detection and
Restoration, Houston, TX, November.
Rittman, B.E., and C.W. Brunner. 1984. The nonsteady-state, biofilm process for advanced organics
removal. J. Wat. Pollut. Control. Fed., 56: 874-880.
Rusten, B. 1984. Wastewater treatment with aerated submerged biological filters, J. Wat. Pollut.
Control. Fed., 56: 424-431.
Shields, E. Pollution Control Engineers Handbook. ISBN 0-934165-02-9.
Suflita, J. 1985. Microbiological principles for the remediation of aquifers. Proceedings of HazPro
'85. Pudvan Publishing, pp. 288-309.
Sullivan, K., and A. Konzen. 1990. On-site treatment of groundwater and hazardous waste using
fixed-film bioreactors. Presented at EnSol 90. Santa Clara Convention Center, Santa Clara, CA.
Sullivan, K., and G. Sklanday. 1988. On-site biological treatment of an industrial landfill leachate
containing toluic acids. Proceedings of the 1988 Annual Conference of the Water Pollution Control
Federation. Dallas, TX.
Sullivan, K., and G. Sklanday. 1987. Decay theory biological treatment for low level organic
contaminated groundwater and industrial waste. Proceedings of the Superfund 87 Conference.
ADDITIONAL REFERENCES ON ANAEROBIC REACTORS
APHA. 1980. American Public Health Association. Standard Methods for the Examination of
Water and Wastewater, 15th edition. American Public Health Association, Washington, DC.
Baek, N.H., and P.R. Jaffe. 1988. Anaerobic mineralization of trichloroethylene. Proceedings of
the International Conference on Physiochemical and Biological Detoxification of Hazardous Wastes,
U.S. EPA.
Battersby, N.S., and V. Wilson. 1989. Survey of the anaerobic biodegradation potential of organic
chemicals in digestion sludge. Appl. Envir. Microbiol. 55:433-439.
Benckiser, G., and J.C. Ottow. 1982. Metabolism of the plasticizer di-n-butyl phthalate by
Pseudomonas pseudodlcaligenes under anaerobic conditions, with nitrate as the only electron
acceptor. Appl. Envir. Microbiol. 44:576-578.
6-3
-------
Bouwer, E.J., and P.L. McCarty. 1985. Utilization rates of trace halogenated organic compounds
in acetate-grown biofilms. Biotechnol. Bioengineering 27:1564-1571.
Bouwer, E.J., and P.L. McCarty. 1983. Transformations of 1- and 2-carbon halogenated aliphatic
organic compounds under methanogenic conditions. Appl. Envir. Microbiol. 45:1286-1294.
Bouwer, E.J., and P.L. McCarty. 1983. Transformations of halogenated organic compounds under
denitrification conditions. Appl. Envir. Microbiol. 45:1295-1299.
Bouwer, E.J., and P.L. McCarty. 1982. Removal of trace organic compounds by activated carbon
and fixed-film bacteria. Envir. Sci. Technol. 16:836-843.
Bouwer, E.J., B.E. Rittmann, and P.L. McCarty. 1981. Anaerobic degradation of halogenated 1-
and 2-carbon organic compounds. Envir. Sci. Technol. 15:596-599.
Boyd, S.A., D.R. Shelton, D. Berry, and J.M. Tiedje. 1983. Anaerobic biodegradation of phenolic
compounds in digested sludge. Appl. Envir. Microbiol. 46:50-54.
Boyle, W.C., and R.K. Ham. 1972. Treatability of leachate from sanitary landfills. Proceedings of
the 27th Industrial Waste Conference, Purdue University.
Brunner, W., D. Staub, and T. Leisinger. 1980. Bacterial degradation of dichloromethane. Appl.
Envir. Microbiol. 40:950-958.
Dagley, S. 1971. Catabolism of aromatic compounds by microorganisms. Adv. Microb. Physiol. 6:1-
46.
Dobbs, R.A. 1990. Factors affecting emissions of volatiles from wastewater treatment plants.
Workshop Report and Proceedings, Air Toxic Emissions and POTWs, Appendix J.
Egli, C., T. Tschan, R. Scholtz, A.M. Cook, and T. Leisinger. 1988. Transformation of
tetrachloromethane to dichloromethane and carbon dioxide \syAcetobacterium woodiL Appl. Envir.
Microbiol. 54:2819-2824.
Engelhardt, G., and P.R. Wallnofer. 1978. Metabolism of di-»-butyl phthalate and related dialkyl
phthalates. Appl. Envir. Microbiol. 35:243-246.
Fatehpure, B.Z., J.P. Nengu, and S.A. Boyd. 1987. Anaerobic bacteria that dechlorinate
perchloroethylene. Appl. Envir. Microbiol. 53:2671-2674.
Feedman, D.L., and J.M. Gossett. 1989. Biological reductive dechlorination of tetrachloroethylene
and trichloroethylene to ethylene under methanogenic conditions. Appl. Envir. Microbiol. 55:2144-
2151.
Galli, R., and P.L. McCarty, 1989. Biotransformation of 1,1,1-trichloroethane, trichloromethane,
and tetrachloromethane by a Clostridium sp. Appl. Envir. Microbiol. 55:837-844.
Gibson, D.T., J.R. Koch, and R.E. Kallio. 1968. Oxidative degradation of aromatic hydrocarbons
by microorganisms. I. Enzymatic formation of catechol from benzene. Biochemistry 7:2653-2658.
6-4
-------
Grbid-Galid, D., and T.M. Vogel. 1987. Pathways of transformation of toluene, benzene, and o-
xylene by mixed methanogenic cultures. Appl. Envir. Microbiol. 53.
Grbid-Galic", D., and T.M. Vogel. 1986. Transformation of toluene and benzene by mixed
methanogenic cultures. Appl. Envir. Microbiol. 53:254-260.
Haller, H.D. 1978. Degradation of mono-substituted benzoates and phenols by wastewater. J.Wat.
Pollut. Control Fed. 50:2771-2777.
Jagnow, G., H. Haider, and P.C. Ellwardt. 1977. Anaerobic dechlorination and degradation of
hexachlorocyclohexane isomers by anaerobic and facultative anaerobic bacteria. Archs. Microbiol.
115:285-292.
Johnson, L.D., and J.C. Young. 1983. Inhibition of anaerobic digestion by organic priority
pollutants. J. Wat. Pollut. Control Fed. 55:1441-1449.
Khan, KA. et al. 1982. Role of surface active media in anaerobic filters. J. Envir. Eng. 108:269-
285.
Khan, K.A., M.T. Suidan, and WJ. Cross. 1981. Anaerobic activated carbon filter for the treatment
of phenol-bearing wastewater. J. Wat. Pollut. Control Fed. 53:1519-1532.
Kohler Staub D. et al. 1986. Evidence for identical dichloromethane dehalogenation in different
methylotrophic bacteria. J. Gen. Microbiol. 132:2837-2843.
LaPat-Polasko, L.T., P.L. McCarty, and AJ. Zehnder. 1984. Secondary substrate utilization of
methylene chloride by an isolated strain of Pseudomonas sp. Appl. Envir. Microbiol. 47:825-830.
Major, D.W. 1991. Field evidence of in situ biodegradation of tetrachloroethylene to ethylene and
ethane at a chemical transfer facility in North Toronto, Ontario.' In: In Situ and On-Site
Bioreclamation. An International Symposium, March 19-21, 1991, San Diego, CA.
Melcer, H., D. Thompson, J. Bell, and H. Monteith. 1989. Stripping of volatile organic compounds
at municipal wastewater treatment plants. In: AWM/EPA International Symposium on Hazardous
Waste Treatment: Biosystems for Pollution Control.
Metcalf & Eddy, Inc. 1979. Wastewater Engineering: Treatment/Disposal/Reuse. 2nd edition.
Narayanan,' B., M.T. Suidan, A.B. Gelderloss, and R.C. Brenner. 1993. Treatment of VOCs in high
strength wastes using an anaerobic expanded-bed GAC reactor. Wat. Res. 27:181-194.
Ng, A.S., M.F. Torpy, and C. Rose. 1988. Control of anaerobic digestion toxicity with powdered
activated carbon. J. Envir. Eng. 114.
Pfeffer, J.T., and M.T. Suidan. 1985. Anaerobic-aerobic process for treating coal gasification
wastewater. In: Proceedings, Industrial Waste Symposium, WPCF Annual Meeting, Kansas City,
MO.
6-5
-------
Platen, H., and B. Schink. 1987. Methanogenic degradation of acetone by an enrichment culture.
Archs Microbiol. 149.
Rochkind-Dubinsky, M.L., G.S. Sayler, and J.W. Blackburn. 1987. Microbial Decomposition of
Chlorinated Aromatic Compounds. Marcel Dekker, New York.
Seager, V.W., and E.S. Tucker. 1975. Biodegradation of phthalic acid esters in river water and
activated sludge. Appl. Envir. Microbiol. 31:29-34.
Shelton, D.R., S.A. Boyd, and J.M. Tiedje. 1984. Anaerobic biodegradation of phthalic acid esters
in sludge. Envir. Sci. Technol. 18:2.
Shelton, D.R., and J.M. Tiedje. 1984. General method for determining anaerobic biodegradation
potential. Appl. Envir. Microbiol. 47:850-857.
Speth, T.F., and RJ. Miltner. 1990. Technical note: adsorption capacity of GAC for synthetic
organics. J. AWWA. 82:72-75.
Suidan, M.T. et al. 1990. Anaerobic treatment of a high strength industrial waste bearing inhibitory
concentrations of 1,1,1-trichloroethane. Wat. Sci. Technol. 23:1385-1393.
Suidan, M.T. et al. 1987a. Anaerobic treatment of coal gasification wastewater. Wat. Sci. Technol
19:229-236.
Suidan, M.T. et al. 1987b. Anaerobic wastewater treatment. Final Report to Department of
Energy, Project No. DOE DE AC21-84MC21281.
Suidan, M.T. et al. 1983a. Anaerobic filter for the treatment of coal gasification wastewater.
Biotechnol. Bioeng. 25:1581-1596.
Suidan, M.T. et al. 1983b. Treatment of coal gasification wastewater with anaerobic filter
technology. J. Wat. Pollut. Control Fed. 55:1263-1270.
Suidan, M.T. et al. 1981a. Anaerobic carbon filters for degradation of phenols. J. Envir. Eng
107:563-579.
Suidan, M.T. et al. 1981b. Continuous bioregeneration of granular activated carbon during the
anaerobic degradation of catechol. Prog. Wat. Technol. 12:203-214.
U.S. EPA. 1984. U.S. Environmental Protection Agency. Guidelines establishing test procedures
for the analysis of pollutants under the Clean Water Act: final rule and interim final rule and
proposed rule. Federal Register Part VIE, 40 CFR Part 136. October 26.
Vargas, C., and R.A. Ahlert. 1987. Anaerobic degradation of chlorinated solvents. J. Wat. Pollut.
Control Fed. 59:594-968.
Vogel, T.M., and P.L. McCarty. 1985. Biotransformation of tetrachloroethylene to
trichloroethylene, dichlroethylene, vinyl chloride, and carbon dioxide under methanogenic conditions.
Appl. Envir. Microbiol. 49:1080-1083.
6-6
-------
Wang, Y.T., M.T. Suidan, and J.T. Pfeffer. 1984. Anaerobic activated carbon filter for the
degradation of polycyclic AT-aromatic compounds. J. Wat. Pollut. Control Fed. 56:1247-1253.
Wang, Y.T., M.T. Suidan, and B.E. Rittmann. 1986. Anaerobic treatment of phenol by an
expanded-bed reactor. J. Wat. Pollut Control Fed. 58:3.
ADDITIONAL REFERENCES ON VAPOR REACTORS
Atkinson, B., and IJ. Davies. 1974. The overall rate of substrate uptake reaction by microbial films.
Part I. A biological rate equation. Trans. Inst. Chem. Engrs. 52:248.
Bohn, H.L. 1975. Soil and compost filters for malodorant gases. JAPCA 25:953.
Bonn, H.L., and R.K. Bohn. 1986. Soil bed scrubbing of fugitive gas releases. J. Environ. Sci.
Health A21:1236.
Carlson, D.A., and C.P. Leiser. 1966. Soil beds for the control of sewage odors. J. Wat. Pollut.
Control Fed. 38:829.
Chang, H.T., and B.E. Rittmann. 1987a. Mathematical model of biofilm on activated carbon.
Envir. Sci. Technol. 21:273.
Chang, H.T.* and B.E. Rittmann. 1987b. Verification of the model of biofilm on activated carbon.
Envir. Sci. Technol. 21:280.
Charpentier, J.C. 1976. Recent progress in two phase gas-liquid mass transfer in packed beds.
Chem. Eng. J. 11:161.
Dombrowski, H.S., and L.E. Brownell. 1954. Residual equilibrium saturation of porous media. Ind.
Eng. Chem. 46:1207.
Don, J.A., and L. Feenstra. 1984. Odor abatement through biofiltration. Paper presented at
Symposium Louvain-La-Neuve, Belgium.
Eitner, D. 1984. Untersuchungen fiber Einsatz und Leistungsfahigkeit von Kompostfilteranlagen
zur biologischen Abluftreinigung im Bereich van Klaranlagen unter besonderer Beriicksichtigung der
Standzeit. (Investigations of the use and ability of compost filters for the biological waste gas
purification with special emphasis on the operation time aspects.) GWA, Band 71, TWTH Aachen.
Harremoes, P. 1976. The significance of pore diffusion to filter denitrification. J. Wat. Pollut.
Control Fed. 48:377.
Hartenstein, H. 1987. Assessment and redesign of an existing biofiltration system. M.S. Thesis,
University of Florida.
Kampbell, D.H., J.T. Wilson, H.W. Read, and T.T. Stocksdale. 1987. Removal of volatile aliphatic
hydrocarbons in a soil bioreactor. J. Air Pollut. Contr. Assoc. 37:1236. .
6-7
-------
Kim, B.R., and M.T. Suidan. 1989. Approximate algebraic solution for a biofilm model with the
monod kinetic expression. Wat. Res. 23:1491.
Leson, G., and AM. Winer. 1991. Biofiltration: an innovative air pollution control technology for
VOC emissions, J. Air Waste Manage. Assoc. 41:1045.
Mackay, D., and W.U. Shiu. 1981. Critical review of Henry's law constants for compounds of
environmental interest. J. Phys. Chem. Ref. Data. 10:1175.
Ottengraf, S.P.P. 1986. Exhaust gas purification. In: Rehm, HJ. and G. Reed, eds., Biotechnology,
vol 8. VCH, Weinheim.
Ottengraf, S.P.P., and R. Disks. 1990. Biological purification of waste gases. Chicaoggi, 41.
Ottengraf, S.P.P., and van den H.C. Oever. 1983. Kinetics of organic compound removal from
waste gases with a biological filter. Biotech. Bioengineering 25:3089.
Ottengraf, S.P.P., van den A.H.C. Oever, and FJ.C.M. Kempenaars. 1984. Waste gas purification
in a biological filter bed. In: Houwink, E.H. and R.R. van der Meer, eds., Innovations in
Biotechnology. Elsevier, Amsterdam.
Pomeroy, R.D. 1963. Controlling sewage plant odors. Consulting Engineer 20:101.
Prokop, W.H., and H.L. Bohn. 1985. Soil bed system for control of rendering plant odors. J. Air
Pollut. Contr. Assoc. 35:1332.
Rittmann, B.E. 1982. The effect of shear stress on biofilm loss rate. Biotech. Bioeng. 24:501.
Rittmann, B.E., and C.W. Brunner. 1984. The non steady state biofilm process for advanced
organics removal. J. Wat. Pollut. Control Fed. 56:874.
Rittmann, B.E., and P.L. McCarty. 1980a. Model of steady state biofilm kinetics. Biotech. Bioeng.
22:2343.
Rittmann, B.E., and P.L. McCarty. 1980b. Evaluation of steady state biofilm kinetics. 22:2359.
Saez, P.B., and B.E. Rittmann. 1988. An improved pseudoanalytical solution for steady state
biofilm kinetics. Biotech. Bioeng. 32:379.
Satterfield, C.N. 1975. Trickle-Bed Reactors, AlChe J. 21:209.
Skowlund, C.T., and D.W. Kirmse. 1989. Simplified models for packed bed biofilm reactors.
Biotech. Bioeng. 33:164.
Smith, K.A., J.A. Bremmer, and M.A. Tatabai. 1973. Sorption of gaseous atmospheric pollutants
by soil. Soil Science p. 313.
Toxics in the Community: National & Local Perspectives. Order no. 055-000-00363-7.
Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.
6-8
-------
Williamson, K., and P.L. McCarty. 1976. A model of substrate utilization by bacterial films. J. Wat.
Pollut. Control Fed. 48:9.
WPCF. 1990. Water Pollution Control Federation. Draft of report on VOC vapor phase control
technology assessment.
ADDITIONAL REFERENCES ON SOIL SLURRY BIOREACTORS
Berg, J.D., T. Bennett, B.S. Nesgard, and A.S. Eikum. 1993. Slurry phase biotreatment of creosote-
contaminated soil. In: Speaker Abstracts In Situ and On-Site Bioreclamation. The Second
International Symposium, San Diego, CA.
Cioffi, J., W.R. Mahaffey, and T.M. Whitlock. 1991. Successful solid-phase bioremediation of
petroleum-contaminated soil. Remediation 373-389.
Glaser, J,A., and P.T. McCauley. 1993. Soil slurry bioreactors: a perspective. In: Speaker
Abstracts In Situ and On-Site Bioreclamation, The Second International Symposium, San Diego, CA.
Griffin, E.A., G. Brox, and M. Brown. 1990. Bioreactor development with respect to process
constraints imposed by bio-oxidation and waste remediation. Appl. Biochem. Biotechnol. 24/25:627-
635.
Irvine, R.L., J.P. Earley, and P.S. Yocum. 1992. Slurry reactors for assessing the treatability of
contaminated soil. Deutsche Gesellschaft fur Chemisches Appartwesen. Chemlsche Technik und
Biotechnologie e.V., Frankfurt, Germany, 187-194.
Jerger, D., D.J. Cady, S.A. Bentjen, and J.H. Exner. 1993. Full-scale bioslurry reactor treatment
of creosote-contaminated material at southeastern wood preserving Superfund site. In: Speaker
Abstracts In Situ and On-Site Bioreclamation. The Second International Symposium, San Diego,
CA.
Luyben, K.Ch.A.M., and RJ. Kleijntjens. 1992. Bioreactor design for soil decontamination.
Deutsche Gesellschaft fur Chemisches Appartwesen. Chemische Technik und Biotechnologie e.V.,
Frankfurt, Germany, 195-204.
Mahaffey, W.R., and R.A.Sanford. 1991. Bioremediation of PCP-contaminated soil: bench to full-
scale implementation. Remediation 305-323.
Ross, D. 1990. Slurry-phase bioremediation: case studies and cost comparisons. Remediation
61-75.
Smith, J.R. 1991. Summary of environmental fate mechanisms influencing bioremediation of PAH-
contaminated soils. Technical Report, Remediation Technologies, Inc., Pittsburgh, PA.
Smith, J.R. 1989. Adsorption/desorption of polynuclear aromatic hydrocarbons in soil-water
systems. Technology Transfer Seminar on Manufactured Gas Plant Sites, Pittsburgh, PA.
6-9
-------
Stroo, H.F. 1989. Biological treatment of petroleum sludges in liquid/solid contact reactors. EWM
World 3:9-12.
Stroo, H.F., J.R. Smith, M.F. Torpy, M.P. Coover, and R.A. Kabrick. No date. Bioremediation of
hydrocarbon-contaminated solids using liquid/solids contact reactors. Remediation Technologies,
Inc. Report. Kent, WA.
U.S. EPA. 1992. U.S. Environmental Protection Agency. Contaminants and remedial options at
wood preserving sites. EPA/600/R-92/182. Cincinnati, OH.
U.S. EPA. 1990. U.S. Environmental Protection Agency. Engineering bulletin: slurry
biodegradation. EPA/540/2-90/076. Cincinnati, OH.
U.S. EPA. 1989. U.S. Environmental Protection Agency. Innovative technology: slurry-phase
biodegradation. OSWER Directive 9200.5-252FS.
6-10
-------
Reactors for Treatment of
Solid, Liquid, and Gaseous
Phases
Chris Nelson
Groundwater Technology, toe
EngIewood,CO
and
Richard Brenner
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH
Bioreactor Presentation Outline
9 Bioreactor Theory
• Aqueous Bioreactors
• Aerobic
• Anaerobic
• Vapor Bioreactors
• Soil Bioreactors
• Biopiles
• Slurry Reactors
Bioreactor Overview
Batch (CSTR) Continuous Plug Flow
NA^V*|NAA/yW^VA
Fixed Film or Suspended Growth
Goal:
Control Important Environmental Conditions
to Maximize Contaminant Degradation
6-11
-------
Biological Reactor
Approaches
i Conventional
•Aerobic Metabolism
•Anaerobic Metabolism
Biological Reactor
Approaches (cant)
Emerging
• Sequential Anaerobic/Aerobic
• Co-Metabolism
» Me thane induced
»Aromatic induced
• Lignin-Degrading Fungi (White Rot Fungi)
• Genetically Engineered Microorganisms
Mass Balances
Accumulation = Inflow - Outflow - Consumption
ds = VAS
dt Y(K,+S)
Contaminant- O2+Nutrients-^^^COj+HjO+ Inorganic Salt
6-12
-------
Laboratory and/or Pilot Studies Should Be
Conducted to Accurately Size Any Bioreactor
Reservoir of
Sterile
Medium
Valve to Control
Flow Rate
Opening for Inoculation
and Air Outlet
Growth Chamber
Air Inlet for
• Forced Aeration
and Agitation
Siphon Overflow
Important Parameters to
Monitor and Control
• Bacterial Concentrations
• Nutrient Concentrations
• Electron Acceptor (e.g., O2)
Concentrations and Transfer
Efficiency
• pH
• Temperature
• Residence Time
Important Parameters to
Monitor and Control (com.)
• Moisture (Soil and Vapor)
• Contaminant and Other Organic
Concentrations (Influent and
Effluent)
• Flow Rate (Loading Rate)
• Off-Gas Concentrations (Biological
and Contaminant)
• Availability of Contaminant, Bacteria,
and Amendments
6-13
-------
r \
Important Parameters to
Monitor and Control (com.)
• Influent Pretreatment
Requirements
• pH adjustment
• Inorganics removal
• Effluent Treatment Requirements
• Solids removal
• Carbon polishing
Applicable Media for
Bioreactor Treatment
•Water
•Vapor
•Soil
Aqueous
Aerobic Bioreactors
•:• 6-14
-------
Types of Aqueous
Bioreactor Designs
• Activated Sludge
• FluidizedBed
• Sequencing Batch
• Trickling Filter
• Fixed Film
Bioreactors
Selection Criteria
• Contaminant Properties
• Biodegradability
• Solubility and Volatility
• Adsorptivity
• Effluent Requirements
• Air Discharge limits
• Water Discharge limits
Bioreactors
Fixed Film Bioreactors
• Low Organic Loading
• Retained Biomass
• Minimum Sludge
Formation
6-15
-------
Bioreactors
Suspended Growth Bioreactors
• High Organic Loading
• More Complete Mixing
Bioreactor Overview
(Suspended Growth)
Wastev
(C,H)
I
rater
r
Nutrients (N, P, K) H o
02 1 C02 I
J^_\__^_ LJ
pH=4.5-9.5
DO >1 ppm
Tenqj.=10-40°C
C/N/P=100/5/l
Clean
Water
— ^-
1
Bacteria
Submerged Fixed-Film
Bioreactor Schematic
Influent
Effluent
Aeration
System
6-16
-------
Biofilm Growth and Detachment
Diffusion of
Oxygen and
Nutrients to
Media Surface
through
Biofilm
Aerobic
Layer
• Biofilm Has
Become Too
Thick
• Oxygen Can No
' Longer Reach
the Surface of
Media
Anaerobic
Conditions
Cause
Detachment at
Media
Interface
Anaerobic Layer
Increasing Growth
Schematic of Bioreactor System
for Ground Water Treatment
pHTarik
Nutrient Tank
Equalization
Effluent
" Carbon Sand Blow<
Tanks Filter
W Wells
Biological Reactor Results
Contaminant-Gasoline
Benzene
Toluene
Ethyl B
Xylene
BTEX
TPH
Influent (ppb)
45.0
6.9
0.6
35.0
88.0
1,300.0
Effluent (ppb)
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
6-17
-------
Biological Treatment of
Petroleum Hydrocarbons
300
20 40 60 80 100
Days of Operation
Activated Sludge Schematic
| VOC Stripper |— i
Inlet*-
r
H o-j Splitter Box |
Equalization
Tank
| Supernatant |
L
-jDige
Waste!
iludge
Contact
Tank
i
Reaeration
Tank
i
-{ClarifierJ-.
Holding
Tank
*
Activated To VOC
Sludge Stripper and
Tertiary Filter for
Further Treatment
Activated Sludge Bioreactor
Performance Data
Influent Effluent Removal
(ppb) (ppb) (%)
Acetone
Benzene
2-Butanone
Chlorobenzene
Chloroform
2-CbJoroethyl
Vinyl Ether
100
120
<100
180
<5
<10
<100
26
<100
40
<5
<10
100
78
NA
78
NA
NA
6-18
-------
Activated Sludge Bioreactor
Performance Data (com.)
Influent Effluent Removal
(ppb) (ppb) (%)
1,1-Dichloroethane 750
1,2-Dichloroethane 100
1,1-Dichloroethene 70
trans-l,2-Dichloroethene 12
1,2-Dichloropropane 21
Ethylbenzene 270
4-Methyl-2-pentanone 300
Methylene Chloride 31
Tetrachloroethane 25
200
44
8
5
7
16
<50
<5
<5
73
56
89
58
67
94
100
100
100
Activated Sludge Bioreactor
Performance Data (com.)
Influent Effluent Removal
(ppb) (ppb) (%)
Toluene 1,000 110
Trichloroethene 250 49
14,1-TricMoroethane 120 17
1,1,2-Trichloroethane <5 <5
Vinyl Chloride 160 <10
Xylenes (total) 700 37
89
80
86
NA
100
95
-------
Aqueous
Anaerobic Bioreactors
CONTROL OF SYNTHETIC ORGANIC CHEMICALS
BY THE ANAEROBIC, EXPANDED-BED, GAC BIOREACTOR
WHY GRANULAR ACTIVATED CARBON?
Superior Microbial Attachment and Sheltering
Permits Acclimation While Still Meeting Effluent Standards
Provides Substrate Storage and Resistance to Perturbed
Loading Conditions
Adsorption of Toxic/Hazardous Compounds
Low Density, Easy-to-Expand Bed
6-20
-------
COMPARISON OF ANAEROBIC
AND AEROBIC EXPANDED BEDS
Anaerobic
• Better Dechlorination
• Lower Biomass Yield
• Less Particle Growth and Carry Over
" Can Handle Higher Organic Concentrations
• Produces Usable End Product (Methane)
• Responds Better to Interrupted Operation
Aerobic
• Requires Less Operating Controls (pH, temp., etc.)
" Faster Kinetics/Smaller Reactor
" Requires Oxygenation
• Potential Stripping of VOCs
EXPANDED BED VS. PACKED BED
ANAEROBIC BIOREACTORS
Expanded Bed
• High Specific Surface Area (4,600 m'/m3 for
1-mm dia. particle and 30% bed expansion) '
Detention Time: 1-12 hr
Energy Intensive (for bed expansion)
Can Handle Some Solids Loading Without Plugging
Requires Skilled Operator
Packed Bed
Low Specific Surface Area (100-200 mz/m3)
Detention Time: 12 nr-4 days
Net Energy Producer
Susceptible to Solids Plugging
Easy to Operate
ANAEROBIC GAC
PRETREATMENT BIOREACTOR
, Minimum
p» Residual
Semlvolatlles
Anaerobic GAC Pretreatment of SOCs
6-21
-------
Methane & CO, Gas
Treated
Effluent
• Fluid Retention
Time in Bloreactor:
3-12 hours
Reclrculatlon
Pump
Expanded G/IC
Gravel Pack
THE ANAEROBIC, EXPANDED-BED, GAG BIOREACTOR
IMPORTANT FEATURES OF THE
ANAEROBIC GAG BIOREACTOR
• Combines Adsorption, Biodegradation,
and Biogeneration of the GAG Medium
• Aerobically Recalcitrant Chlorinated VOCs
are Degraded by Reductive Dechlorination
- e.g., PCE -»TCE •*• DCE -»• Ethylene
• Low Sludge Production
ANAEROBIC GAG PROCESS LIMITATIONS
• Desirable bioreactor operating
temperature is 35°C
• Not suited for wastes with high
suspended solids concentrations
• A few compounds, such as chloroform
and carbon tetrachioride, may inhibit
reactor performance above 2 mg/L
6-22
-------
EXAMPLE OF GAG ADSORPTIVE CAPACITY IN ANAEROBIC
EXPANDED-BED REACTOR TREATMENT OF o-CHLOROPHENOL
• System Operation
• Steady State
• Volumetric Loading Rate = 22 g COD/kg GAC-d
• Steady State Performance
..Component
Influent (mo/Li Effluent fmo/U
Phenol
Acetic Acid
o-ChlorophenoI
1,000
2,000
2,000
0.93
12.99
26.80
Accidental Slug Loading
• On Day 668, a slug dose of 8 L of feed containing 8 g Phenol, 16 g
Acetic Acid, and 16 g o-Chlorophenol was accidentally Introduced
Into reactor
• Normal feed was then continued
• Impact of slug loading on performance shown on next graph
EXAMPLE OF GAC ADSORPTIVE CAPACITY IN
ANAEROBIC EXPANDED-BED REACTOR
100
50
' Acetate = 12.99
n Phenol ~~ 0 93
• o o— Chlorophenol
= 26.8
_c
L
1 —
.V-~L_ -
-n-ft- — 6^oa=M-.Q — »-4
Methane !
3 10
\2 i-l
3roducti
o
o
p
5 w
H
• TJ
n ^
655
665
675
665
Time, d
EFFECT OF PHENOL LOAD PERTURBATION ON PERFORMANCE
OF GAC AND ANTHRACITE ANAEROBIC REACTORS
274 276 278 280 274 276 278 280 282
Time, d
6-23
-------
CHLORINATED ALIPHATIC VOCs TREATED
BY THE ANAEROBIC GAC PROCESS*
Compound Influent Cone. (mg/L) % Removal
V
Perchloroethylene
Trlchloroethylene
Dlchloromethane
1,1,1- Trlchloroethane
1,1- Dlchloroethane
Carbon Tetrachlorlde
M-ln. dla. Pilot Units
20 >99
0.4 >98
1.2-20 >96
20-400 >99
0.1 >87
20 >99
f
^
AROMATIC AND KETONE VOCs TREATED
BY THE ANAEROBIC GAC PROCESS*
Compound
Chlorobenzene
Ethylbenzene
Toluene
Acetone
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
•4-ln. die. Pilot Units
Influent Cone. (mg/L) % Removal
1.1 - 20 >85
0.6 >86
8.2 - 20 >87
10 - 755 >96
12 >97
10 >94
-.. , _^
SELECTED SEMIVOLATILES TREATED
BY THE ANAEROBIC GAC PROCESS*
Compound Influent Cone. (mg/L) % Removal
Llndane
Naphthalene
Phenol
o-ChlorophenoI
Pentachlorophenol
Nitrobenzene
•d.In rilii. Pllnt Units
10 >99
30 >99
3 - 2,959 >97
2,000 >98
1,320 >99
0.5 - 100 >98
6-24
-------
CASE STUDY 1 - PRETREATMENT OF HAZARDOUS LEACHATES
• Location: EPA Test and Evaluation Facility, Cincinnati, OH
• Scale: Two 4-ln. dla. Bloreactors
• Waste Streams: Two Hazardous Leachates Spiked with Consortium
of 10 VOCs and 4 Semlvolatlles
• Empty Bed Contact Time: 6 hr
• Operating Temp.: 35°C
• Study Goal: Effective Pretreatment for Subsequent
Aerobic Treatment
CASE STUDY 1 - PRETREATMENT GOALS
• Reduce SOC Levels before Subsequent
Aerobic Treatment, Minimizing:
- Air Stripping of VOCs
- Poor Dechlorlnation
- Pass Through of Semivolatiles
• Reduce Leachate Strength:
- COD
- BOD
CASE STUDY 1
CHARACTERISTICS OF LEACHATE A
Parameter
Concentration (mg/L)
Total COD 1,261
Soluble COD 1,183
Volatile Acids COD 143
Sulfate 108
Ammonia 305
Summary: Weak strength, little biodegradable organlcs present,
moderate sulfate concentration
6-25
-------
CASE STUDY 1
CHARACTERISTICS OF LEACHATE B
Parameter
Concentration (mg/L)
Total COD 3,616
Soluble COD 3,504
Volatile Acids COD 2,464
Sulfate 23
Ammonia • 311
Summary: Moderate strength, substantial biodegradable organlcs
present, low sulfate concentration
CASE STUDY 1
EFFECT OF LEACHATE STRENGTH ON SOC REMOVAL
Reactor A - Reducing Potential Resulted Primarily
from Sulfate Reduction
Reactor B - Reducing Potential Resulted Primarily
from Methanogenesis
CASE STUDY 1 - SYNTHETIC ORGANIC CHEMICALS
SPIKED INTO LEACHATES A AND B
Volatile Organic Compounds (mg/L) *
Acetone 10,000
Methyl Ethyl Ketono 5,000
Methyl Isobutyl Ketone 1,000
Trlchloroethylene 400
1,1-Dlchloroethane 100
Chloroform 5,000
Mothylene Chloride 1,200
Chlorobonzono 1,000
Ethylbenzene 600
Toluene 8,000
Semlvolatlle Organic Compounds (mg/L) *
Phenol 2,600
Nitrobenzene 500
Trlchlorobenzene 200
Dlbutyl Phthalate 200
* Concentrations typical of CERCLA leachates
6-26
-------
CASE STUDY 1 - PROJECT OPERATION
Two Reactors Treating Leachates A and B
Containing Spiked SOC Supplement
Phases ; Days
1. 10 L/day---EBCT = 6 hr 0-67
2. 30% SOC Supplement w/o Chloroform 68-105
3. 60% SOC Supplement w/o Chloroform 106-133
4. 100% SOC Supplement w/o Chloroform 134-448
5. Chloroform Addition (2.0 mg/L) 449-553
6. Chloroform Addition (3.5 mg/L) 554-763
7. Chloroform Addition (5.0 mg/L) 764-823
CASE STUDY 1
CHLOROFORM ADDITION
• 2.0 mg/L
- Reactors A and B Successfully Adapted to the New Feed
• 3.5 mg/L
- Reactor A Continued to Successfully Treat Leachate A
Feed Supplemented with 300 mg/L Sulfate
- Reactor B Gas Production Ceased within 1 Week (Failure)
• Follow-On Operations
- Reactor A Continued to Successfully Treat Leachate A
Containing 5.0 mg/L Chloroform and 300 mg/L Sulfate
- Reactor B Recovered after Chloroform Removed from Feed
CASE STUDY 1 - ACETONE REMOVAL IN REACTORS A AND-B
Day
6-27
-------
CASE STUDY 1 - MEK REMOVAL IN REACTORS A AND B
0 100 200
Day
,£> CASE STUDY 1 - MIBK REMOVAL IN REACTORS A AND B
& .„_
>
*j
o
in
O)
0 100 200 300 400 500 600 70S 800 900
J
X.
,0
O,
oj
a
OJ
0)
o
O 100
CASE STUDY 1 - TCE REMOVAL IN REACTORS A AND B
10O ZOO 30O 400 500 600 700 800 900
Day
6-28
-------
CASE STUDY 1 - DICHLOROETHANE REMOVAL IN REACTORS A AND B
0)
o
ft
O
• pH
Q
I
CASE STUDY 1 - CHLOROFORM REMOVAL IN REACTOR A
o Intlueul Chloroform
• Effluent. Chloroform
J
-\
024 072 720
Time, day
CASE STUDY 1 - MECLZ REMOVAL IN REACTORS A AND B
Day
6-29
-------
CASE STUDY 1 - ilOLOGICAL VS. A050RPTIVE
REMOVAL OF KeCl, IH REACTOR A
CASE STUDY 1 - CHLOROBENZENE REMOVAL IN REACTORS A AND B
0)
CJ
0)
N
a
0)
fl
o
O
Day
CASE STUDY 1 - ETHYLBENZENE REMOVAL IN REACTORS A AND B
Day
6-30
-------
CASE STUDY 1 - TOLUENE REMOVAL IN REACTORS A AND B
100 200 300 400 500 600 700 800 900
day
CASE STUDY 1 - PHENOL REMOVAL IN REACTORS A AND B
100 200 300 400 _ 500 600 700 800 900
Day
CASE STUDY 1 - NITROBENZENE REMOVAL IN REACTORS A AND B
100 200 300 400 500 600 700 800 900
Day
6-31
-------
CASE STUDY 1 - TRICHLOROBENZENE REMOVAL IN REACTORS A AND B
100 200 300 400 500 600 700 800 900
Day
CASE STUDY 1 - IMPACT OF CHLOROFORM ON TRICHLOROBENZENE
REMOVAL IN REACTOR A
'-*.
»^
ft
ft !5°
^•^
.
REMOVAL IN REACTOR B . ^
A InrhlcnL Chloroform
O liiMuonl U
• EKIucilL U
100 200 300 400 500 600 700 600 900.
O
*+-)
O
6-32
-------
CASE STUDY 1 - DIBUTYLPHTHALATE REMOVAL IN REACTORS A AND B
Day
CASE STUDY 2
PRETREATMENT OF PROPELLANT PRODUCTION WASTEWATER
• Site: Radford (MD) Army Ammunition Production Facility
• Major Waste Constituents: DNT, Ethanol, and Ether
• Successful Treatment at Bench Scale on Synthetic Waste at 12-hr
Detention Time (4-in. dia., 10-L volume)
- Complete Disappearance of Ethanol and Ether
- Complete Transformation of DNT to Diaminotoluene (DAT)
- DAT Easily Oxidized Aerobically
• Above Unit Transported to Radford and Operated Successfully on Real
Production Facility Waste Stream
• Pilot Unit (4-ft dia., 1-gpm flow) is in Design for Scaled-Up Testing
and Detention Time Optimization at Radford
REPRESENTATIVE ANAEROBIC
GAG BIOREACTOR SIZES
Industrial
Pretreatment
Flow (gpd)*
Typical Bioreactor
Size Range (gal)
10,000 1,750- 2,500
100,000 17,500- 25,000
500,000 85,000 - 125,000
* Assumes Influent COD = 2,000-4,000 mg/L
6-33
-------
EXISTING ANAEROBIC GAG PROCESS
FIELD APPLICATIONS
• Envirex Corp., Milwaukee (Mobile
Units, Both Anaerobic & Aerobic)
- Contaminated Ground Water
(Primariliy BTEX)
• Liege, Belgium - Coke Oven Wastes
• Nizhnii Novgorod, Russia - Electronics
Plant Solvent Wastes (6-ft dia.)
SUMMARY
Anaerobic, Expanded-Bed, GAC Bioreactor has
been Successfully Tested for Pretreatment of:
- Hazardous Leachates at Pilot Scale
- Hazardous Industrial and
Commercial Wastes.at Pilot and Full Scale
Process Ready for Broad Range
of Field Applications
6-34
-------
Vapor
Bioreactors
CONTROL OF VOLATILE ORGANIC CHEMICALS
BY THE AIR BIOFILTER
ANAEROBIC GAC
PRETREATMENT REACTOR
AIR BIOFILTER
Minimum
fe. Residual
^emivolatlles
Integrated Biological Treatment of VOCs
6-35
-------
VOC AIR EMISSIONS
Increased Health Risk
Control Applications
- Direct Industrial and Commercial Releases
- Superfund and RCRA Sites
- Contaminated Drinking Water, Ground Water
and Wastewater
Cost-Effective Solution
- Improved Air Biofilter Technology
VOC CONTROL TECHNOLOGIES
Process
Thermal
Condensation
Adsorption
Bloscrubber
Blofllters
Soil
Peat
Improved
Ret. Time Contaminant Concentration
-sec
-5 mln
-2 mln
~5 mln
< 15 mln
< 2 mln
< 2 mln
Low < 300 Moderate High >
VOC LOADING PPMV
2,000
ADVANTAGES OF
AIR BIOFILTRATION
• Low Capital and Operating Costs
• Low Energy Usage
• Simple Design and Operation
• Destroys Compounds Unlike Some
Other VOC Control Technologies
(Condensation, Adsorption)
6-36
-------
Soil Blofllter
HT < 15 mln
loading < 300 ppm
Clean Air
t
Blotower
RT < 2 mln
loading < 300 ppm
Peat
COMMERCIAL BIOFILTERS
EXISTING COMMERCIAL BIOFILTERS
• ClalrTech (Netherlands)
- Trade Name: "Bloton" System
- Marketed in USA by Ambient Engineering Co., NJ
- Media: Peat with Bulking Agents and Solid
Nutrients and Buffers
- Installations: Worldwide
• Blofiltratlon, Inc. (Florida)
- Trade Name: "Blkovent" System
- Media: Multiple Choices, e.g., Compost, Wood
Chips, and Mulch Mixture or Soil with
Appropriate Solid Nutrients and Buffers
- Installations: Worldwide
• TNO (Dutch Research Organization)
- Media: Peat, Compost, and Bulking Agents Mixture
- Installations: 20 Units Built for Dutch Gas Utility
REPORTED EUROPEAN PERFORMANCE
Hydrogen sulflde
Dimethyl sulffde
Turpene
Removals %
-99
-91 '
-98
Organo-sulfur gases -95
Ethyl benzene -92
Tetrachloroethylene -86
Chlorobenzene -69
6-37
-------
CASE STUDY - MONSANTO CHEMICAL CO.
• Two Full-Scale Bikovent Compost Biofilter
Systems Started Up in Nov. 1992 at Polymer
Plants in Springfield, MA, and Trenton, Ml
Installed by Monsanto to Achieve as a .
Corporate Goal 90% Reduction in SARA Title III
Air Emissions between 1987 and End of 1992
DESIGN INFORMATION FOR
MONSANTO BIOFILTERS
Media Area: 7,000 sq ft (approx. 120 ft x 60 ft)
Media Depth: 4.5-5.0 ft
Media Composition: Compost, Wood Chips, and Mulch
Top Layer of Media: 6-9 In. of Bark Chips to
Prevent Vegetative Growth
OPERATING CONDITIONS FOR MONSANTO BIOFILTERS
• VOC Concentrations: 200-500 ppmv as Propane In
Process Air Waste Stream
• VOC Chemicals:
- Alcohol (highest cone.)
- Aldehyde (< 100 ppmv)
- Ester (< 100 ppmv)
- Minor Quantities of Compounds Derived
from the Above Three
• Air Stream Flow: 20,000 acfm
• Avg. Actual Empty Bed Residence Time: 2 mln
Assuming Entire Bed Is Active
• • Air Stream Temp.: 20-35°C
• Air Stream Moisture: Humidified to 95%+
6-38
-------
PERFORMANCE DATA FOR
MONSANTO SPRINGFIELD BIOFILTER
« Pilot-Scale Tests: 90-95% Removals at 50-60 sec
Residence Time
• Full-Scale Tests: (Start-Up Date 11/19/92)
- Total System Pressure Drop = 1.5 In. H20
Date of Testing 12/4/92 12/7/92
Process Exhaust 260 ppmv 326 ppmv
Cooler/Humldler Exhaust 215 ppmv 228 ppmv
(Inlet to Blofllter)
Blofllter Exhaust 15 ppmv 17 ppmv
% Removals*
Total System
Blofllter Only
•One Minor Compound Not Efficiently
95
93
Removed (< 90%)
95
93
LIMITATIONS OF CURRENT
FULL-SCALE SYSTEMS
Not Optimized for Degradation
of Important VOCs
Applied Primarily to Low VOC
Concentrations and Loading Rates
Little Data on Performance vs.
Contaminants, Loading Rates, and
Operating Conditions (e.g., pH)
Media Becomes Clogged in 1-3 Years
and Must be Disposed of
Clean Air
MEDIA TYPES
Pellets
Straight Passages .
AIR WITH VOCs
MICROORGANISMS
IMMOBILIZED ON
SUPPORT MEDIA
NUTRIENT
SOLUTION
FRESH
NUTRIENTS
IMPROVED BIOFILTER
6-39
-------
ADDITIONAL ADVANTAGES OF
IMPROVED AIR BIOFILTERS
• No Media Replacement
• No Hazardous Media
Residue to Dispose of
EPA STUDIES
Biotower system with palletized
media (activated carbon)
Tested VOCs
Toluene
Influent
Concentration
% Removal
520 ppmv >99
Methylene Chloride 180 ppmv >99
Trichloroethylene 25 ppmv >99
STRAIGHT PASSAGES BIOFILTER COLUMN
Nutrients
Top View
Gas + Contaminants
6-40
-------
REMOVAL EFFICIENCIES FOR
STRAIGHT PASSAGES BIOFILTER
Chemical
Toluene
Methylene Chloride
Ethylbenzene
Chlorobenzene
Trichloroethylene
Loading •
(ppmv)
450
150
20
40
25
Percent
Removal
>99
100
100
>95
-35
CASE STUDY FOR PELLETIZED
CERAMIC MEDIA BIOFILTER
• Location: EPA Test & Evaluation
Facility, Cincinnati, OH .
• Celite Media
• 5.75-in. Bed Dia.
• 4-ft Media Depth
• Co-Current Gas, Nutrient, and
Buffer Flow from Top
• Air Stream Spiked with Toluene
(477)
Biofilter I.D. - B 3/4 in.
Toluene Feed - 0.24 kg/m3.day
COD Loading = 0.76 kg/m3.day
v % Toluene Removed
• Influent Toluene
• • Effluent Toluene
Retention Time, min
Performance of Palletized Ceramic Medium Biofilter
During a 102—Day Cycle Test at Constant Organic Loading
6-41
-------
PELLETIZED CERAMIC BIOFILTER (5.75-ln. ID) PERFORMANCE
BEFORE BACKWASHING (BEGINNING AT DAY 233)
Inf.
Toluono
(ppmv)
476
SOS
503
494
503
Dat.
Time
(mln)
11.8
9.9
7.8
5.9
4.0
Organic*
Loading
(kg COD/m'/day)
0.71
0.90
1.13
1.47
2.22
%
Toluene
Removed
100
97
95
99
92
. Head-
Loss
(In. HaO)
16
19
23
25
42
No. of
Days of
Operation
6
2
7
8
8
* Typical Loading for Activated Sludge = 1.0 kg COD/m'/day
PELLETIZED CERAMIC BIOFILTER (5.75-ln. ID) PERFORMANCE
AFTER BACKWASHING* (BEGINNING AT DAY 263)
Day
Sampled
263
266
267
268
Inf.
Toluene
(ppmv)
502
504
502
509
Det.
Time
(mln)
4.0
4.0
4.0
4.0
Organic
Loading
(kg COD/m'/day)
2.21
2.22
2.21
2.25
%
Toluene
Removed
90
89
89
89
Head-
Loss
(In. HZ0)
0
0.1
0.1
0.1
Backwnshed with Five Bed Volumes of Water at 10 gpm/sq ft on Day 263
Soil Bioreactors
•Biopiles
•Slurry Reactors
6-42
-------
Abovegrpund
Bioremediation
Treatments
Cells
(Biopiles)
Treatability of Various Contaminants
High
Degradability
Low
Availability
High (Soluble) Low (Strongly Sorbed)
High Treatability
• Gasoline
• Diesel
• Jet Fuel
• PetroleumSolvents
•BTEX
•Naphtha
•Mineral Spirits
• Phenols
Low Treat ability
• Chlorinated Solvents
• Fuel Additives
•MIBE
•TBA
• Ethers
Moderate Treatability
• PASS
• API Separator Sludge
• No. 6 Fuel
• Crude Oil
• PCBs <1242
• Lo-O Pesticides
• Phthalates
Very Low Treatability
• PCBs >1242
• Hi-Q Pesticides
Methods of Soil Biotreatment
Nutrients
Slurry Reactors
•Aeration by Air Diffusion &
High Turbulence Agitation
•Nutrients Added as
Solution to Maintain
Threshold Level
Soil Piles
•Aeration by Mechanical Air
Drive (Vacuum or Pressure)
• Nutrients Applied as a'
Concentrate to Soil Matrix
during Construction
6-43
-------
Effect of Bacterial Augmentation
100
80
Degradation 60
Rate
potential 40
20
cterial Augmentation
Stimulated Indigenous Bacteria
4 6
Weeks Since Startup
10
Effect of Nutrient Addition on
Biodegradation
1,200
1,000
Gasoline, 80°
ppm
600
400
200
Q
^Aeration Only
\V
V^
— ^k
— ^^^.
Aeration^^
Nutrients ^^"-
0 10 20 30 40 50
Days of Treatment
Rates of Biodegradation as a
Function of Product and Soil Type
Gravel
Medium Sand
Fine Sand
SiltySand
Silts & Clays
Gasoline
0 40 80 120 160 200 240
Days of Treatment
6-44
-------
Modified Land Treatment Design
100'
100'
6" of Coarse Sand
12 mil Reinforced PE tiner
24"Min'
270'
18" of Impacted Soil
g.g* Cross Section
Diagram of Soil Treatment System
Tarp
i
Treatment Cell
Vent
lines
Vapor
Oxidizer
Nutrient
Addition
Pad
Sump
. _t Vacuum Blower
Comparison of
Land Treatment & Soil Piles
Parameter/Function
Containment
Land Required
Oxygenation
Vapor Control
Nutrient Addition
Soil Conditioning
Moisture Control
Construction ,
Capital
Time to Treat
Land Treatment
Clean Soil Bed
36 sq ft/cu yd
Tilling
None
Spread & Till
None (Tilling)
Rain/Till
Soil Spread
Land & Tractor
6-12 Months
Soil Piles
Pad & Liner
3-4 sq ft/cu yd
Mechanical (Vacuum)
Cover/Collection
Spray & Soak
Mechanical/Chemical
Spray & Soak
Piles & Pipes
Land, Pad, Pumps
2-6 Months
6-45
-------
Maximum Oxygen Uptake
Contaminant
Type
Oxygen Uptake
(Ib O2/cu yd-day)
light Hydrocarbons
(Gasoline & Jet Fuel)
Diesel & Fuel Oil
Sludges
2.45
0.33
0.026
Typical Costs for SoU Biotreatment
140
120
100
Costs, 8°
S/cuyd go
40
20
A-Construction
i
:
2lB D
JL~
High
1 fflft
Low
', B-O&M.
C-Containment
D-Soil Conditioning
-
E-Soil Disposal
F-Total Cost Max.
G-Total Cost Min.
Availability Availability
(Ught Products) (Heavy Products)
Slurry Bioreactor
Technology
6-46
-------
o
LJJ O
go
m
o
o:
6-47
-------
\
SLURRY BIOREACTOR
TECHNOLOGY
"IS-
IB—••
•-HH-
SLURRY BIOREACTOR
The use of mixing conditions to hasten the
blodegradatlon of soil bound contamination
as a suspended water-slurry of the
contaminated soil and biomass capable of
degrading the targeted constituents of the •
waste.
SLURRY PHASE
BIOREACTORS
Process description
AdvantagesAJmKations
Targeted waste streams
Reactor design
Performance
Principles
6-48
-------
\
ADVANTAGES/LIMITATIONS
Advantages
- more rapid treatment rates
- greater degree of process flexibility
- waste containment
- reduced space limitations
Limitations
- higher cost of operation
- lack of application database
- optimal operation conditions require investigation
- normally operated as batch mode
- few fuH scale operations, many pHot applications
WASTE STREAMS
Wood Treating Waste
Oil Separator Sludge
Munitions (soils, sediments, sludges)
Pesticides
Halogenated Aromatic Hydrocarbons
REACTOR CONFIGURATIONS
• Batch
• Sequenced
• Continuous or semicontinuous
6-49
-------
\
REACTOR DESIGN
• Aerated lagoons
• Low-sheer airlift reactors
• Fluldlzed bed soil reactors (research level)
AERATED LAGOON DESIGN
NUTRIENTS
AERATION
MCROORGANtSMS
,LL!—cEb nEb cEb
\ """"
\ "~~"
\ cb <=*=> , c3=>
Surface Aeration
Limited suspension capabilities
Most applications have poorly determined
hydrodynamics
Control of dead space or holdup locations In
the suspension basin
Poor definition of process controls and
process modifications to improve
performance
6-50
-------
AIRLIFT SLURRY BIOREACTOR
\
AIRLIFT BIOREACTOR
Hydrodynamics more easily understood
Claims to support treatment of 30-50% solids
by weight
Higher degree of control for:
- aeration
— mixing
— temperature
- emission control
MATERIAL HANDLING
Size classification equipment
Slurry making and pumping capability
Hydrocyclone for sand fraction rejection for
certain reactor configurations
Slurry dewatering capability
6-51
-------
SLURRY BIOREACTOR
PROCESS COMPONENTS
EPA BOAT STUDY
BntStu So» PAH CoKtHn&xt
PAH
N«p«hiJm«
AuiupMtiyten.
Ac.r-pth.0.
Fkjonn*
PtBnrtlno.
Arthncvn*
TOTAL
MEAN (5)
ms*g
2143.3
17/4
1937.1
867.8
519.8
307.0
5891.5
SM.D.V.
mg*g
710
7.6
1016.8
288.4
12.1
34.7
EPA BOAT STUDY
BaseKne SoH PAH Concentrations
TOW,
TOVLPAHt
161.1
9SU
2ECL3
1195
soon
109779
13.6
1117
6-52
-------
Percent finer by weight
-j.roco.&.oio>-jool
by
t— — I!
idled
nille:
- l-r i.
(f%
1 1
«S
H
'D
**
\
^
\.
f
*
.\
J
^
\
\
\T?
^\
k^
t
p
: -
^
•««
ft
10
1 0.1 0.01
GRAIN DIAMETER (millimeters)
Fluorarrthena
Pywn«
B«nzo(a)anthra«ene
Chrys»n«
Benzolblfluoranthana
Benzo(k)fluoranth«iHi
Benzo(a)pyr«n0
Dib«nzo(a,h)anthr»cene
lnd«no(1^>3<«d)pyr«ne
Week
4- TO 6-RING PAHS (SOLIDS, AVG. OF 5 REACTORS)
2500 1
,
2000;
E
O. 1
°-
1000 J
500
0
> 2
— • — Naphthalene
— • — Acenaphthylene
* Acenaphthene
— •»• — Fluorene
— * — Phenanthrene
— * — Anthracene
4 68 10 12
Week
2- AND 3-RiNG PAHs (SOLIDS, AVG. OF 5 REACTORS)
6-53
-------
SLURRY APPLICATIONS
WOOD TREATING WASTE
CCNTAMUOTS
RESULTS
Mnoodhe
OMH.AR
OtftfCA
PCP&PAH
Cone, reduced
850X180%
56 days
PCP<13.1 ppm
PAHS 0.5.0.03 win
\
SLURRY APPLICATIONS
WOOD TREATING WASTE
90%PCP
SLURRY APPLICATIONS
WOOD TREATING WASTE
CONTAMMANTS
RESULTS
SOUTH CAVALCAK St
HOUSTON. TX
Lower ting*
nnwvcdln
pnftnnca to
Ngh«r rings
6-54
-------
LIMITING FACTOR ANALYSIS
LIMITING
FACTOR
POTENTW.
IMPACT
CONTROL
STRATEGIES
Visile CompolH.lon
kKtxntsttnt Traahntnt
Pomurt R.Kii.
Witfi Homoj. nM Ion
\
-lotubBty
LIMITING FACTOR ANALYSIS
USOTNG
FACTOR
POTENTIAL
MPACT
Mirfng
•Rheotogicol behavior
-Particlosize
Density
•Aggregate tarring
propefties
Extended treatment periods
Gas Feed
-Density reduction
'Oxygen uptake
LIMITING FACTOR ANALYSIS
UKffDNG
FACTOR
POTENTIAL
MPACT
CONTROL
STRATEGIES
Mcrobtat Population
-Nutrients
-pH
-Temperature
Rate of Treatment
Inhibitory Materials
-Heavy Metals
-HflK/ Chlorinated
Organlcs
Removal or Dilution
6-55
-------
CURRENT
FEED CHARACTERISTICS
Organlcs: 0.25- 25% by weight
Solids: 10-40% by weight
Solids particle size: less than 0.25 inch.
Temperature: 15-35*0
pH 4.5-8.8
\
LIMITING FACTORS
Biological
Mlcroblal population
Blodegradability of pollutant(s)
Availability of required nutrient
concentrations to growing blomass
Oxygen concentration
pH range
LIMITING FACTORS
Physical
Variable waste composition
Wide particle size distribution
Inadequate mixing
Temperature range
6-56
-------
\
LIMITING FACTORS
Chemical
Pollutant water solubility
Heavy metals
Highly chlorinated organics
Some pesticides and herbicides
Inorganic salts
AERATED LAGOON DESIGN
sSs
ANALYSIS OF PHYSICAL
FACTORS
LIMITING
FACTORS
WASTE COMPOSITION
PARTICLE SIZE
MIXING
TEMPERATURE
POTENTIAL
IMPACT
INCONSISTENT
TREATMENT
CONTACT
MINIMIZATION
CONTROL
ACTIONS
6-57
-------
TREATMENT COMPONENTS
Solid (soil, sludge, sediment)
Liquid (water)
Gas (air, oxygen)
\
FLUIDIZED SUSPENSION
FLUIDIZED SOIL BIOREACTOR
6-58
-------
SOIL TREATMENT:
LAND TREATMENT
Daniel F. Pope
Dynamac Corporation
Robert S. Kerr Environmental Research Laboratory
Ada, OK
and
John E. Matthews
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK
INTRODUCTION
Land treatment involves use of natural biological, chemical, and physical processes in the soil
to transform organic contaminants of concern. Biological activity apparently accounts for most of
the transformation of organic contaminants in soil, although physical and chemical mechanisms can
provide significant loss pathways for some compounds under some conditions.
MICROORGANISMS AND BIOREMEDIATION
Both bacteria and fungi have been shown to be important in bioremediation processes. Most
research in bioremediation has centered on bacteria, but fungi can play an important role in
bioremediation processes, especially with halogenated compounds. In almost all cases,
bioremediation relies on communities of microorganism species, rather than on one or a few species.
Bioremediation consists of using techniques for enhancing development of large populations
of microorganisms that can transform the pollutants of interest, and bringing these microorganisms
into intimate contact with the pollutants. Several physical constraints on the use of microorganisms
for soil remediation are related generally to the problem of bringing contaminants and
microorganisms together in close contact under environmental conditions desirable for microbial
activity. Generally, a contaminant must move through the waste/soil matrix and pass through a
microorganism's cell membrane in order for the microorganism to transform the contaminant,
although in some cases contaminants can be transformed by extracellular enzymes without entering
7-1
-------
into the microorganisms. Waste compounds that have low solubility in water are slow in moving
from soil adsorption sites or free-phase droplets into the soil water and from there into the
microorganism. Wastes in solid matrices (soil) have less solvent (water) in which to be dissolved for
mobility, are more likely to have highly variable concentrations throughout the matrix, are harder
to mix thoroughly, and can be adsorbed onto matrix solids. All of these factors tend to limit
accessibility of contaminant compounds to the microorganisms.
LAND TREATMENT TECHNOLOGY
Land treatment techniques most often are directed for treatment of contaminated soil, but
certain petroleum waste sludges have long been applied to soil for treatment. Ideally, the
contaminated soil can be treated in place (in situ). Often, however, the soil must be moved to a
location better suited to control of the land treatment process (ex situ). Land treatment in situ is
limited by the depth of soil that can be treated effectively. In most soils, oxygen diffusion sufficient
for desirable rates of bioremediation extends only a few inches to a foot down into the soil. Ex situ
treatment generally involves application of lifts of contaminated soil to a prepared-bed reactor, which
is usually lined with clay and/or plastic liners; provided with irrigation, drainage, and soil water
monitoring systems; and surrounded with a berm.
Soil can be screened before application to remove any debris greater than 1 in. in diameter,
especially if significant amounts of debris or rocks are present. Any large debris that may adsorb
the waste compounds (i.e., wood) should be removed if possible. Small rocks and other relatively
nonadsorptive wastes can be treated if they do not interfere with tillage operations.
The soil should be near the lower end of the recommended soil moisture percentage range
before tilling, since tilling very wet or saturated soil tends to destroy the soil structure and reduce
microbial activity. Tillers tend to mix the soil only along the tractor's line of travel, so tillage should
be carried out in varying directions, i.e., lengthwise of the land treatment unit (LTU), crosswise, and
on the diagonal.
Once desired target levels of compounds of interest are established, data obtained from the
LTU monitoring activities can be statistically analyzed to determine if and when desired levels are
reached and the LTU is ready for another lift of soil to be applied.
NUTRIENTS, CARBON SOURCES, AND OTHER ADDITIVES
Land treatment unit microorganisms require carbon sources and nutrients. The nutrient
requirements for biodegradation in the field have not been thoroughly studied, and detailed
information is not available to indicate the optimal levels of particular nutrients in field situations,
so application rates usually are based on nutrient ratios or concentrations developed for crop plants.
Fertilizers will supply the nutrients; wood chips, sawdust, or straw can supply carbon. Various
animal manures often are used to supply both carbon sources and nutrients. Organic amendments
increase the water holding capacity of the soil, which is often desirable in the poor soils found at
many plant sites, but can be a liability where land treatment is conducted in areas of high rainfall
and poor drainage. Manure should be applied to each lift at the rate of about 3 to 4 percent by
weight of soil. Agricultural fertilizer usually is supplied in pelleted form suitable for easy application
over large areas of soil. The pelleted fertilizers can be applied with a hand- or tractor-operated
cyclone spreader. Soluble fertilizers that can be applied through irrigation systems are available.
7-2
-------
Sometimes inorganic micronutrients, microbial carbon sources, or complex growth factors
might be needed to enhance microbial activity. Animal manures generally will supply these factors.
Proprietary mixtures of various of these ingredients sometimes are offered for sale to enhance
microbial activity. Proof of the efficacy/cost effectiveness of these mixtures is lacking in most cases.
The same could be said for microorganism cultures sold for addition to bioremediation units.
Two factors limit use of added microbial cultures in LTUs: (1) nonindigenous microorganisms rarely
compete well enough with indigenous populations to develop and sustain useful population levels,
and (2) most soils with long-term exposure to biodegradable wastes have indigenous microorganisms
that are effective degraders given proper management of the LTU.
SOIL MOISTURE CONTROL
Soil moisture should be maintained in the range of 40 to 70 percent of field capacity,
allowing soil microorganisms to obtain air and water, both of which are necessary for useful rates
of aerobic biodegradation. If soils are allowed to dry excessively, microbial activity can be seriously
inhibited or stopped. Continuous maintenance of soil moisture at adequate levels is of utmost
importance.
Moisture can be enhanced by traveling gun or similar irrigation systems, which can be
removed to allow easy application of lifts. Hand moved sprinkler irrigation systems more often are
used, although they usually are more expensive. It is possible to use permanently installed sprinkler
systems with buried laterals and mains, but the sprinkler uprights must be avoided when placing lifts
and performing other LTU operations. Since one sprinkler will not apply water uniformly over an
area, sprinkler patterns should overlap to provide more uniform coverage. The usual overlap is
around 50 percent; that is, the area covered by one sprinkler reaches to the next sprinkler. Highly
uniform coverage is difficult to achieve in the field, especially in areas where winds of more than 5
mph are common.
The irrigation system should be sized to allow application of at least 1 in. of water in 10 to
12 hours. The rate of water application should never be more than the soil can absorb with very
little or no runoff. Since LTUs consist of bare soil, runoff can cause significant erosion very rapidly.
Very seldom will application rates of more than 0.5 in. of water per hour be advisable; heavy soils
with slopes greater than 0.2 to 0.3 percent will require considerably lower rates of water application.
A water meter to measure the volume of water applied is helpful in controlling application.
Surface drainage of the LTU can be critical in high rainfall areas. Soil saturated more than
an hour or two greatly reduces microbial action. The LTU surface should be sloped 0.5 to 1.0
percent. Greater slopes will allow large amounts of soil to be washed into the drainage system
during heavy rains. Even a slope of 0.5 to 1.0 percent will allow much soil to be eroded; therefore,
the drainage system should be designed to allow collection and return of eroded soil to the treatment
unit.
Underdrainage generally is provided by a sand layer or a geotextile/drainage net layer under
the LTU. The system should be designed so that any water in soil lifts over field capacity will be
drained quickly away so microbial activity will not be inhibited. The lifts of contaminated soil usually
are placed on a bed of sand or other porous soil. This gives a "perched", water table—the
contaminated soil lift will take up water from irrigation or rain until field capacity, is reached, then
the lift begins to drain excess water into the treatment unit drainage system. The interface between
7-3
-------
the lift and the coarse layer underneath should be composed of well-graded materials so that the
transition from the (usually) relatively fine soil texture of the lift to the coarse texture of the
drainage layer is gradual rather than sudden.
Biological reactors commonly are used to treat leachate prior to discharge. Alternatively,
effluent from the biological treatment unit can be applied to the LTU through the irrigation system.
Nutrients and microorganisms from the biological treatment system can enhance the microbial
activity within the LTU.
REFERENCES
Bulman, T.L., S. Lesage, PJ.A. Fowlie, M.D. Webber. The persistence of polynuclear aromatic
hydrocarbons in soil. PACE Report No. 85-2. Petroleum:Association for Conservation of the
Canadian Environment. Ottawa, Ontario. November.
Lynch, J., and B.R. Genes. 1989. Land treatment of hydrocarbon contaminated soils. In: P.T.
Kostecki andEJ. Calabrese, eds., Petroleum Contaminated Soils, Vol. 1: Remediation Techniques,
Environmental Fate, and Risk Assessment. Lewis Publishers, Chelsea, MI, p. 163.
Park, K.S., R.C. Sims, R.R. Dupont, WJ. Doucette, and J,E. Matthews. 1990. Fate of PAH
compounds in two soil types: influence of volatilization, abiotic loss and biological activity. Environ.
Toxicol. Chem. 9:187.
Rochkind, M.L., J.W. Blackburn, and G.S. Sayler. 1986. Microbial decomposition of chlorinated
aromatic compounds. EPA/600/2-86/090, Hazardous Waste Engineering Research Laboratory, U.S.
Environmental Protection Agency, Cincinnati, OH.
Ross, D., T.P. Marziarz, and A.L. Bourquin. 1988. Bioremediation of hazardous waste sites in the
USA: case histories. In: Superfund '88, Proc. 9th National Conf., Hazardous Materials Control
Research Institute, Silver Spring, MD, p. 395.
Sims, J.L., R.C. Sims, and I.E. Matthews. 1989. Bioremediation of contaminated surface soils.
Robert S. Kerr Environmental Research Laboratory, U.S. Environmental Protection Agency, Ada,
OK. EPA-600/9-89/073. August.
Sims, R.C. 1990. Soil remediation techniques at uncontrolled hazardous waste sites. J. Air &
Waste Management Assoc. 40.
Sims, R.C., WJ. Doucette, J.E. McLean, WJ. Grenney, and R.R. Dupont. 1988. Treatment
potential for 56 EPA listed hazardous chemicals in soil. Robert S. Kerr Environmental Research
Laboratory, U.S. Environmental Protection Agency, Ada, OK. EPA/600/6-86/001. April.
Sims, R.C., D.L. Sorensen, J.L. Sims, J.E. McLean, R. Mahmood, and R.R. Dupont. 1984. Review
of in-place treatment technologies for contaminated surface soils - Volume 2: Background
information for in situ treatment. Risk Reduction Research Laboratory, U.S. Environmental
Protection Agency, Cincinnati, OH. EPA-540/2-84-003b.
7-4
-------
St. John, W.D., and DJ. Sikes. 1988. Complex industrial waste sites. In: G.S. Omenn, ed.,
Environmental Biotechnology - Reducing Risks from Environmental Chemicals through
Biotechnology. Plenum Press, New York, NY, p. 163.
U.S. EPA. 1991. U.S. Environmental Protection Agency. On-site treatment of creosote and
pentachlorophenol sludges and contaminated soil. Extramural Activities and Assistance Division,
Robert S. Kerr Environmental Research Laboratory, Ada, OK. May. EPA/600/2-91/019.
U.S. EPA. 1990. U.S. Environmental Protection Agency. Handbook on in situ treatment of
hazardous waste-contaminated soils. Risk Reduction Research Laboratory, Cincinnati OH
EPA/540/2-90-002. January. '
U.S. EPA. 1989. U.S. Environmental Protection Agency. Guide for conducting treatability studies
under CERCLA. Office of Solid Waste and Emergency Response and Office of Research and
Development, Washington, DC. Contract No. 68-03-3413. November.
U.S. EPA. 1989. U.S. Environmental Protection Agency. Treatability potential for EPA listed
hazardous chemicals in soil. Robert S. Kerr Environmental Research Laboratory Ada OK
EPA/600/2-89/011. '
U.S. EPA. 1986. U.S. Environmental Protection Agency. Permit guidance manual on hazardous
waste land treatment demonstrations. Office of Solid Waste and Emergency Response. Washington
DC. EPA-530/SW-86-032. '
7-5
-------
SOIL TREATMENT:
DEVELOPMENT AND EVALUATION OF COMPOSTING TECHNIQUES
FOR TREATMENT OF SOILS CONTAMINATED WITH HAZARDOUS WASTE
John A. Glaser and Carl L. Potter
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH
INTRODUCTION
Composting is a method of waste treatment whereby the organic component of a solid waste
stream is biologically decomposed under controlled conditions to a state in which it can be handled,
stored, and/or applied to the land without adversely affecting the environment (Golueke, 1977).
Composting involves a process of biological decomposition of organic components within a
complex pile of organic material. Composting seldom occurs naturally since organic waste material
in nature is usually distributed in a thin layer over the Earth's surface.
Composting, as a solid waste management tool, is a treatment process involving adding
organic material (nutrients and bulking agents) to the solid waste (soil, sludge, sediments) and
placing the mixture in a pile. The added organic matter, usually more than 20 percent by weight,
provides support to a diverse microbial consortium of aerobic and facultative anaerobic
microorganisms. Soil application of composting includes remediation of soil contaminated with
munitions, fuels, oily wastes, pesticides, and PAHs.
Composting can be anaerobic, but most methods use aerobic conditions. Bacterial attack on
the organic materials is considered to be the "active stage" of composting. The curing stage, a slow
process occurring after the active stage, consists of a fungal attack in dryer parts of the pile, and an
actinomycete attack in the deeper parts. Optimum conditions for composting may vary depending
on a number of factors, but generally 55°C temperature, 40 to 60 percent moisture content, a
carbon-to-nitrogen ratio of 20:1 to 30:1, and aerobic conditions with frequent mixing applied to
materials with a high surface area are considered best. Bulking agents may consist of sawdust, corn
cobs, straw, hay, alfalfa, peanut hulls, rice hulls, or other organic materials.
Mesophilic (35°C to 55°C) composting might prove to be the most effective at destruction
of wastes. It might not be practical, however, to maintain a temperature below 55 °C from an
7-6
-------
economic standpoint if it requires too much energy to keep the temperature that low.
thermophilic (> 55°C) conditions might be desirable for pathogen destruction.
Also,
Common composting configurations are static pile, windrow, and in-vessel. Windrow
composting uses piles arranged in continuous lines called windrows. Windrows are turned frequently
for aeration and mixing. Windrow composting is suitable for high volumes of waste, has low capital
requirements, offers moderate mixing capability, and has a good oxygen transfer capability.
Disadvantages of windrow systems include large space requirements, aeration dependent on operator
skill, pile subject to environmental conditions, and limited process control.
Static pile composting uses piles that are not mixed or turned after the composting process
has begun. An aeration and heat management system of vacuum or pressure air supply provides
some process control. An air exchange manifold of perforated pipe is located under the pile. Air
blowers are activated by temperature sensors or gas probes in the pile or piping system. Vacuum
systems pull air from the pile surface into the pile, allowing good control of volatile emissions and
odors, moisture management by application of water to the pile surface, and even distribution of
heating/cooling. The pressure system pushes air into the pile core, allowing gas phase treatment of
air stream volatiles from other sources and rapid control of heating/cooling since air moves directly
into the pile core.
In-vessel composting, in large closed reactor vessels, typically allows more complete mixing
and process control. The system may be highly automated to reduce operator person-hours and
facilitate constant data collection. Volatiles are readily controlled since the system is totally
enclosed. Reseeding (bioaugmentation) is easily accomplished, and the process is generally faster
than other composting methods. On the down-side, in-vessel composting has high capital
requirements, and requires more complex equipment, and few data exist concerning the process.
Siting requirements for a compost operation include space for the pile and operations
including composting; curing and handling; and storing bulking agents, soil, and equipment.
Strategically, siting requires consideration of access, runoff control, proximity to population, and
typical public relations problems associated with treatment of hazardous waste.
Composting faces limitations and disadvantages with respect to process control, emissions
control, and the extent of remediation. Emissions control requires control of volatiles, odor,
leachate, and runoff. Emissions control is especially difficult with windrow systems. Metals and
some pesticides can inhibit microbial activity, and some organic compounds might not be
metabolized.
REFERENCES
Ayorinde, O.A., and C.M. Reynolds. 1991. Low-temperature effects on the design and performance
of composting of explosives-contaminated soils. U.S. Army Corp of Engineers CRRELReport 91-4,
USATHAMA, March.
Fogarty, A.M., and O.H. Tuovinen. 1991. Microbial degradation of pesticides in yard waste
composting. Microbiological Reviews 55(2):225-233.
Golueke, C.G. 1977. Biological Reclamation of Solid Wastes. Rodale Press, Emmaus, PA, p. 2.
7-7
-------
Griest, W.H., R.L. Tyndall, AJ. Stewart, C.-h Ho, K.S. Ironside, J.E. Caton, W.M. Caldwell, and
E. Tan. 1991. Characterization of explosives processing waste decomposition due to composting.
DOE, ORNL, ORNI/IM-12029.
Hart, S.A. 1991. Composting potentials for hazardous waste management. In: H.M. Freeman and
P.R. Sferra, eds., Innovative Hazardous Waste Treatment Technology Series, Volume 3 - Biological
Processes, Section 3.2.
Inbar, Y., Y. Chen, and Y. Hadar. 1991. Carbon-13 CPMAS NMR and FTIR spectroscopic
analysis of organic matter transformations during composting of sblid wastes from wineries. Soil
Science 152(4):272-282.
Nakasaki, N., A. Watanabe, and H. Kubota. 1992. Effects of oxygen concentration on composting
organics. Biocycle 52-54, June.
Petruska, J.A., D.E. Mullins, R.W. Young, and E.R. Collins, Jr. 1985. A benchtop system for
evaluation of pesticide disposal by composting. Nuclear and Chemical Waste Management 5:177-
182.
Qui, X. andMJ. McFarland. 1991. Bound residue formation in PAH-cOntaminated soil composting
using Phanerochaete chrysosporium. Hazardous Waste and Hazardous Materials 8(2):115-126.
Smith, W.H., Z.P. Margolis, and B.A. Janonis. 1992. High altitude sludge composting.
Biocycle 68-71, August. -.:-.',
Snell Environmental Group, Inc. 1984. Rate of biodegradation of toxic organic compounds while
in contact with organics which are actively composting. National Science Foundation. NITS PB84-
193150.
USATHAMA. 1990. U.S. Army Toxic and Hazardous Materials Agency. Evaluation of composting
implementation: A literature review.
USATHAMA Report #TCN 8963, AD-A243 908, NTIS 91-18764.
Valo, R., and M. Salkinoja-Salonen. 1986. Bioreclamation of chlorophenol-contaminated soil by
composting. Appl. Microbiol. Biotechnol. 25:68-75.
7-8
-------
Land Treatment
Daniel F. Pope
Dynamac Corporation
R.S. Kerr Environmental Research Laboratory
and
John £. Matthews
R.S. Kerr Environmental Research Laboratory
U. S. Environmental Protection Agency
Ada, OK
Land Treatment
Biological, chemical,
physical processes
transform contaminants
Biological Activity
Most transformation of
organic contaminants
Physical, chemical
mechanisms also
involved
7-9
-------
Ultraviolet Light
Soil surface
Higher P AHs
Volatilization
Low Molecular Weight
Compounds
BTEX
Naphthalene
Methyl naphthalenes
Hydrolysis
Pesticides
Amides
Triazines
Carbaraates
Thiocarbamates
Nitriles
Esters
Phenylureas
7-10
-------
Know Thv Waste
Relative importance of
processes varies widely for
different compounds under
different circumstances
Compounds Amenable To
Land Treatment - PAHs
2 ring PAHs - readily degraded,
volatile, leachable
3 ring PAHs - degradable, leachable
4 ring PAHs - fairly degradable,
leachable
5-6 ring PAHs - difficult to degrade
Compounds Amenable To
Land Treatment
Phenols
Penta &
Tetrachlorophenol
Difficult over 1000 ppm
Other phenolics
7-11
-------
Compounds Amenable To
Land Treatment
Hydrocarbons
Aliphatics 1-8 C chains
Readily degradable
Volatile
Compounds Amenable To
Land Treatment
Hydrocarbons
• Most 12-15+ C chains
• Slow degradation
• Relatively immobile
• Relatively nontoxic
Compounds Amenable To
Land Treatment
Hydrocarbons
• Branched chain,
unsaturated, rings
• Degradable
7-12
-------
Compounds Amenable To
Land Treatment
BTEX
Degradable
Volatile
Compounds Amenable To
Land Treatment
Munitions - more often
composted
Phthalates
Pesticides
Microorganisms and
Bioremediation
Bacteria, fungi important
Most research on bacteria
Fungi with halogenated
compounds
7-13
-------
Microorganisms and
Bioremediation
Bioremediation relies on
microbial communities
Bioremediation
Developing large populations
of microorganisms that can
transform pollutants
Bringing microorganisms
into intimate contact with
pollutants
Physical Constraints on
Soil Bioremediation
Getting contaminants,
microorganisms in close
contact under
environmental
conditions desirable for
microbial activity
7-14
-------
Constraints
Contaminant must move
through waste/soil
matrix
Pass through cell
membrane
Extracellular enzymes
<
Constraints
Low Water Solubility
(4, 5, 6 ring PAHs)
Slow moving from
adsorption sites or free
phase into water, then
into microorganism
Constraints
Wastes In Solid Matrices (soil)
1 Less solvent (water) for mobility
1 Highly variable concentrations
throughout matrix
Harder to mix thoroughly
High tendency to be adsorbed
onto matrix solids
7-15
-------
Microorganisms
Most live in water
Water in tank reactors,
aquifers, or thin film of
water on a soil particle
Microorganisms
Sensitive to osmotic
potential
Process waters,
contaminated soils -
high dissolved salts
Slow changes better
Microorganisms
Electron Acceptor
Most LT Microbes
aerobic
7-16
-------
Supplying Electron
Acceptors
Injecting air/oxygen
supplying compounds
Tilling soil to allow air
to enter
Microorganisms
Water/Oxygen
• Balance between water
and oxygen
• More water, less oxygen
• In soil, oxygen/water
inversely related
Microorganisms
PH
• pH 6-8
• Pollutant chemistry
7-17
-------
Microorganisms
Toxicity
Heavy metals
Halogenated organics
Pesticides
Microorganisms
Toxicity
• Response highly
variable
• Treatability study
Microorganisms
Carbon sources
Mineral nutrients
(nitrogen, phosphorous,
etc.)
7-18
-------
Carbon. Nutrients
• Pollutants may supply
carbon source, some
nutrients
• Often nutrients must be
supplied
Nutrients
Agricultural fertilizers
Manures, etc.
Nutrient Balance
•C:N:P 100-300:10:1
• Carbon degradability
7-19
-------
Carbon
Manure, straw, wood
chips, sawdust
Cometaholites
Little research except
chlorinated hydrocarbons,
anaerobic conditions
Thought to be necessary for 5-6
ring PAHS
Possibly supplied in manures,
vegetation enhancement
Microorganism
Populations
More microorganisms,
faster transformation
What is being counted?
7-20
-------
Microorganism
Populations
Quantitative measure of
microorganism
population
Index to microbial
environment
Microorganism
Populations
Plate counting
Respiration
Total Counts
Living Counts
Land Treatment
Technology
Contaminated soil
Sludge application to
soil
7-21
-------
In-Situ - Ex-Situ
Control - runoff,
leachate, volatiles
In-Situ - Soil depth
Effective oxygen
diffusion
Bioventing for greater
depths
In-Situ
Treat surface soil,
remove
Treat surface soil, deep
till
7-22
-------
fc
Semi fn-Situ
Remove soil to depth
Add lifts back to
excavation for treatment
Tillage Depth
Most tractor mounted tilling devices
till down to one foot
Large tractors, specialized
equipment till to three feet or more
Large augers move soil from 50-100
feet to surface, but practicality not
fully shown
Ex-Situ
Application of lifts of contaminated
soil to prepared bed reactor
Clay and/or plastic liners
Bed of porous soil
Irrigation, drainage and soil water
monitoring systems
Berm
7-23
-------
Land Treatment
Lift Depth
Twelve inches or less
preferred
Soil Type
Limited to 6 to 24 inches of soil
Limited in heavy clay soils,
especially in high rainfall areas
Oxygen transfer limitations
Substrate availability
Soil Type
Working With
Heavy Soils
Shallow lifts
Improve tilth
7-24
-------
Improving Tilth
Bulking Agents
Organic Matter
Improving Tilth
High Sodium Content
Add gypsum
(calcium sulfate)
Preparing Soil For
Application
• Screen to remove debris
greater than 1" diameter
• Remove large debris
that may adsorb waste
compounds
7-25
-------
Avvlmns Soil
Apply lightly contaminated
soil at beginning of operation
Apply manure, nutrients,
water until total
microorganism populations
106-107 CFU/gram
Tilling
Enhance oxygen
infiltration
Contaminant mixing
with microorganisms
Tilling
Lower end of soil moisture
percentage range before tilling
Tilling very wet or saturated
tends to destroy soil structure,
reduce microbial activity
Wait 24 hours after irrigation or
a significant rainfall event
7-26
-------
Tilling Schedule
Compromise
Tilling - Mixing
Mostly along line of
travel
Till in varying
directions
Tilling Equipment
Rotary tiller for tilling,
mixing purposes
Disk harrow not
recommended
Subsoil plow, chisel plow to
break up zone of compaction
7-27
-------
Tilling
Subsequent lifts tilled into
top 2" or 3" of previous lift
To mix populations of well
acclimated microorganisms
Lift Application Timing
Based on reduction to
defined levels of particular
compounds or categories of
compounds
Usually more detailed
sampling to determine finish
Nutrients, Carbon
Sources, and Other
Additives
7-28
-------
Carbonaceous
( "Organic ") Amendments
Animal manures
Wood chips, sawdust
Straw, hay
Carbonaceous
Amendments
Carbon
Some nutrients
Bulking agent
Adsorbent
Carbonaceous Adsorbents
Slow migration
May sequester contaminants
Increase permeability
Increase oxygen demand
Increase water holding
capacity
7-29
-------
Carbonaceous
Amendments
Application Rates
• Must be balanced with
nutrients
• 3-4% by weight of soil
Carbonaceous
Amendments
• Manures often mixed
with bedding
• Bulking agent
• Nutrient demand
,
Carbonaceous
Amendments
• Small particle size
• Thoroughly mixed with
soil
7-30
-------
Fertilizers
Ammonium nitrate
Triple superphosphate
Diammonium phosphate
Fertilizers
Can cause pH to drop
Equivalent indicated on
bag
Fertilizers
Pelleted form for easy
application
Unformulated fertilizer
difficult to spread evenly
Hand or tractor operated
cyclone spreader
7-31
-------
Fertilizers
Soluble Forms
Can be applied through irrigation systems
Application rates may be closely controlled
Applications can easily be made as often as
irrigation water is applied
Immediately available to microorganisms
Fertilizers
Soluble Forms
Equipment meters
concentrated nutrient
solutions into irrigation
system on demand
Soil Nutrient Levels
Nutrient requirements not
thoroughly studied
Detailed information not available
to indicate optimal levels
Difficult to show response in field
7-32
-------
Soil Nutrient Levels
Soil concentration
Concentration ratio
Micronutrients
Carbonaceous
amendments
Inorganic fertilizers
Proprietary
Micronutrients
Generally easily supplied
with readily available
horticultural fertilizers
7-33
-------
Complex Nutrients
Vitamins
Growth Factors
Complex Nutriente_
Easily shown in lab culture,
with defined media
Difficult to show
effectiveness in field
Bioausmentation
Indigenous isolated,
cultured
Nonindigenous
Genetically engineered
7-34
-------
Bioauementation
Nonindigenous microbes
rarely compete well enough
to develop, sustain useful
population
Bioauementation
Most soils with long term exposure
to biodegradable wastes have
indigenous microorganisms that are
effective degraders given proper
management of the LTU
Bioauementation
Little data from well
designed experiments to
show efficacy
7-35
-------
Soil Moisture Control
40-80% of field capacity
Field Capacity
• Soil micropores filled with water
• Soil macropores filled with air
• Microorganisms get air and water
Soil Moisture
Maintaining 40-80% of FC
allows more rapid movement of
air into soil, facilitating aerobic
metabolism without seriously
reducing supply of water to
microorganisms
7-36
-------
Soil Moisture
Some evidence that
continuous maintenance
at high levels better
Requires careful
management
Soil Moisture
• If soils dry excessively,
microbial activity seriously
inhibited, stopped
• Maintenance at proper level
is not trivial
Measuring Soil Moisture
Gravimetric
Tensiometer
Gypsum blocks
Capacitance effect
Neutron probe
7-37
-------
Irrigation Systems
Traveling gun
Hand moved surface mounted
Permanently installed -
buried laterals, mains
Fire hose
Irrigation Systems
• Operating pressure 30 to 50
lb/in2
• Usual overlap 50%
• Uniform coverage difficult
• Winds > 5 mph problematic
Irrigation Systems
• At least 1" water in 10-12
hours
• No more than 0.5" per hour
• Little or no runoff
7-38
-------
Application Rates
Estimate water uptake rates
from Soil Manual data
Soil Manuals may refer to
soils with vegetative cover
Reduce suggested rates by
half
Application Rates
Water meter to measure
volume applied
Rain gauges at various
locations on LTU
Surface Drainage
Critical in high rainfall areas
Saturation > hour greatly
reduces microbial action
7-39
-------
Surface Drainage
Surface should be sloped
0.5-1.0%
Greater slopes - erosion
hazard
Design to allow collection,
return of eroded soil
Internal Drainage
Sand/gravel layer
Geotextile/drainage net
layer
Internal Drainage
• Lifts usually placed on
bed of sand, other
porous soil
• Perched water table
7-40
-------
Perched Water Table
• Lift takes up water until field
capacity
• Then begins to drain excess
water
• Lower lift layer may remain
overly wet
Internal Drainage
Interface between lift &
drainage layer - well graded
materials
Transition from lift to drainage
layer gradual
Water movement through
interface enhanced
Internal Drainage
• Reduces tendency for soil lift
to become saturated
• Interface graded by tilling lift
into top of drainage layer
7-41
-------
LTU Leachate & Runoff
Recycled onto LTU
With or w/o treatment
Treated and discharged
Leachate & Runoff
Treatment
• Biological
• Adsorption
Disposal of Treated Soil
Replace in excavation
Disposal cell
7-42
-------
LT As Part of a
Treatment Train
High organics may
inhibit solidification
/stabilization
LT Disadvantages
Time
High Concentrations
Low Concentrations
Final Levels
Space Requirements
Volatiles/Dust/Leachate
LT Disadvantages
Time
Slow
Recalcitrant Compounds
Determine Time
7-43
-------
LT Disadvantages
High Concentrations
May require mixing
with low level
contaminants
LT Disadvantages
Low Concentrations
May not cause
significant reduction
LT Disadvantages
Final Levels
• Levels below ppm range
difficult
• Vegetation enhancement
may help
7-44
-------
LT Disadvantages
Space
• Treatment area
• Stockpiling area
• Equipment operation
LT Disadvantages
Volatiles
• Maximizing volatiles
• Covers expensive
LT Disadvantages
Dust
Water application
7-45
-------
LT Disadvantages
Leachate
Recycle or treat for ex-situ
Hard to capture for in-situ
Reduce mobility
Control water
LT Costs
• Earthmoving
• Containment
• Monitoring
• Operations
• Volatiles control
Development & Evaluation of
Composting Techniques for
Treatment of Soils Contaminated
with Hazardous Waste
Carl Potter and John Closer
Risk Reduction. Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH
7-46
-------
SOIL COMPOSTING
Definition
... method of solid waste management
whereby the organic component of the solid
waste stream is biologically decomposed un-
der controlled conditions to a state in which it
can be handled, stored, and/or applied to the
land without adversely affecting the environ-
ment.
Golueke, 1977
COMPOSTING PROCESS
Mix Soil With:
• Bulking Agent (Sawdust, Corn Cobs, Straw)
• Moisture
• Nutrients (Manure, Sludge, Food Scraps)
PRINCIPLES
1 Operation can be conducted under both aerobic and
anaerobic conditions
A wide variety of cheap bulking agents are available
> Desired biological activities can be selected by
process manipulation
1 Can operate under mesophlllc and thermophillc
conditions
• Inoculation with nonindlgenous microorganisms is
possible
7-47
-------
WASTE STREAMS
• Wood Treating Waste
• Oil Separator Sludge
• Pesticides
• Halogenated Aromatic Hydrocarbons
SOIL COMPOST SYSTEM
Advantages
Inexpensive
Very Little Energy Requirement
Requires Less Soil Screening than Bloslurry
SOIL COMPOST SYSTEM
Disadvantages
• Difficult to Control Volatile Emissions
• Very Slow Process
• Not a Well Controlled Process
7-48
-------
LIMITATIONS OF COMPOSTING
• Metals may be toxic to microorganisms
• Metals cannot be eliminated by microorganisms
• Some organic compounds may not be metabolized
CONTROL REQUIREMENTS
• Condensate - moisture in the air pulled through
the pile
• Leachate - drainage from the compost process
• Runoff - need to control the amount of
precipitation reaching the compost pile
LAYOUT SIZE REQUIREMENTS
• Bulking agent storage
• Mixing
• Composting pad
• Processing (curing)
• Contingency
• Material handling
7-49
-------
LAYOUT STRATEGIC
CONSIDERATIONS
• Access
• Runoff control
• Proximity to population
• Typical public relations problems associated
with treatment of hazardous waste
TYPES OF COMPOST OPERATIONS
Static Pile
- Forced air
Windrow (Turned Pile)
- Turn pile periodically to aerate
In-Vessel
- Forced air
- Regular mixing
- Climate control
Schematic Diagram of
Extended Aerated Pile
Bulking Materials and Sludge
Ui
or Screened
Compost
Perforated Trap for <
Pipe Water
Filter Pile
Screened
Compost
Composting Extended Piles with Forced Aeration
7-50
-------
Static Pile Composter
Side View
/
Visqueen /-
Cover y
"s°"""\
Nutrients
Aeration
Microorganisms
TJH
ADVANTAGES
Static Pile Systems
• Low capital costs
• More space efficient than windrow
• Process control may be partly automated
• Downflow system can be interfaced with a
biofilter to control VOCs
DISADVANTAGES
Static Pile Systems
• Requires more land than in-vessel option
• Requires higher energy input than windrow
• Subject to the influence of climate conditions
• Poor control of pollutant fate in treatment
system
7-51
-------
Windrow Compost System
Windrow
Mobile Composter
ADVANTAGES
Windrow Systems
• Capacity to handle high volume of material
• Relatively low capital investment
- pad for piles
- windrow machine
- front-end loader
• Good oxygen transfer
• Intermediate stage of mixing
DISADVANTAGES
Windrow Systems
• Not space efficient
• Equipment maintenance cost can be significant
• Aeration Is highly dependent on operator skill
• Subject to changing climate conditions unless
covered
• Demands significant moisture control
• Requires large volume of bulking agent
• Poor control of pollutant treatment fate in system
7-52
-------
V
Composting
MX
-1
Air./
-Outfe<
In-Vessel
Composter
ADVANTAGES
In-Vessel Systems
Space efficiency
Improved process control over open
systems
Process control may be automated
Independent of climate
Facilitates mass balance monitoring
DISADVANTAGES
In-Vessel Systems
• High capital investment
• General lack of operating data
• Process susceptible to mechanical disruption
• Compost compaction may confound results
• Low operational flexibility
7-53
-------
GENERAL ECONOMIC CONSIDERATIONS
• Cost of Bulking Agents and Nutrients
• Cost of Excavation
Time Factor (Slow Process)
* Cost of Handling Finished Product
Disposal
Further Remediation
KEY ECONOMIC FACTORS
Process Selected
Volume of Contaminated Soil
Soil Throughput
Amendment Costs
Treatment Time
ECONOMIC FACTORS
Composting
VOCCwtrelCwti
Low Med High
EXPECTED COST
7-54
-------
COMPOSTING DEMONSTRATION
AT UMATILLA DEPOT
• Windrow Process Design
• Turned Once Per Day
• 55 ° C Temperature
• Soil Content 30% (by volume)
• Amendments (by volume)
- Cow manure
- Vegetable waste
- Alfalfa / Sawdust
• 40 Days Treatment Time
COMPOSTING OF
EXPLOSIVES-CONTAMINATED SOILS
Applications/Contaminants
- High Contamination Levels
- Soils and Sludges
- TNT, RDX, HMX, Tetryl, DNT, NC
Advantages
- Demonstrated Effective
- Product Is Enriched
- Various Reactor Configurations
Disadvantages
- Minimal Field Experience
WINDROW COMPOSTING
EXPLOSIVES REDUCTION
Day
0
!
10
15
20
40
TOT
M)
1563
101
23
19
11
4
RDX
M
953
1124
623
18
5
2
HMX
(W'l)
156
151
119
111
2
5
% Reduction
TNT RDX HMX
U
J3.5
98.5
HJ
99.3
99.7
0.0
0.0
34.6
0.7
99.5
913
00
0.0
23.7
24.4
»7
KM
1-55
-------
WINDROW COMPOSTING DEMONSTRATION
Explosives Reduction
2000
1000
0 510152025303540
TNT
RDX
HMX
MECHANICAL IN-VESSEL COMPOSTING
Explosives Reduction
6000
TOT
RDX
HHX
COMPOSTING OF EXPLOSIVES
TNT BIOTRANSFORMATION
Q
3
10 20 30 40 50
2,4-DA-S-NT
2-A-2.6-NT
2,e-DA-4-NT
2-A-4.6-NT
7-56
-------
COMPOST TOXICOLOGICAL AND
CHEMICAL CHARACTERIZATION
• Reduced Toxicity
4. 90 to 98% Reduction in aquatic toxicity
observed in CCLT leachates
+ No rat oral toxicity detected
4 No mutagenicity observed in CCLT leachates
4- Biotransformation to less toxic compounds
• Chemical binding of radio-labeled
TNT to the compost
UMDA FEASIBILITY STUDY
Comparison of Alternatives
Overall Protection
Meets Cleanup Requirements
Effectiveness
Reduces Toxicity
Long-Term Protection
Time
INCINERATION
Yes
Yes
99.99%
>90%
Yes
16 Months
COMPOSTING
Yes
Yes
97 to 99%
>90%
Yes
24 Months
7-57
-------
-------
BIOVENTING
Ronald J. Hicks
Groundwater Technology, Inc.
Concord, CA
and
Greg Sayles
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH
Bioventing is an in situ process of moving air through contaminated soils to increase soil
oxygen concentrations and stimulate the biodegradation of contaminants by indigenous microbial
populations. Bioventing is best suited at a site at which aerobic organisms capable of degrading the
contaminant are present and oxygen is limited.
The bioventing process begins by drilling injection wells into the ground where the
contaminant exists. The number, location, and depth of the wells depend on the geological, chemical,
and microbiological features of the site and other engineering considerations.
Air is delivered to the subsurface by either negative or positive pressure. Some of the
advantages and disadvantages of either approach are shown in Table 1.
Each system is designed to bring oxygen into the soil. The oxygen then is used by the
indigenous microorganisms to degrade the contaminant. In addition to oxygen, other nutrients might
be pumped into the soil either through the wells or through an independent nutrient gallery. By
providing the nutritional requirements for microbial growth (i.e., oxygen and nutrients), the
microorganisms will use the contaminants in the soil as a food source and convert them to
nonhazardous compounds such as carbon dioxide and water.
8-1
-------
TABLE 1. Advantages and Disadvantages of Oxygen Delivery System
Oxygett Delivery System
Positive Pressure
Advantages
No off-gas treatment
Long gas residence time
Greater depth of treatment
Disadvantages
Needs extensive soil gas
monitoring
Less control of gas flow
Limited in shallow
environments
' •"'
Negative Pressure
Control of off-gas
Ease of monitoring process
Little soil gas monitoring
Off-gas treatment likely
Limited at deep sites
Off-gas treatment costs
Before considering or designing a bioventing program, appropriate site information needs
to be obtained. Site information such as contaminant identity and spatial distribution helps in
determining the treatability of the site. Nutrient, pH, moisture content, and cation exchange capacity
(CEC) help to determine the mass load and mass transport of required amendments at the site.
Performing laboratory treatability studies will help determine the maximum extent of degradation
that can be expected and whether cleanup objectives can be reached using bioventing. In addition,
air permeability studies, performed either in the laboratory or in field tests, will help determine the
design of the oxygen transport system. The identity and mass of off-gases that might be expected can
be determined either in laboratory or pilot-scale tests.
The rate of degradation and, hence, the expected time to clean up the site can be estimated
during laboratory studies. A more accurate means of determining rates of degradation at the site,
however, is to perform an in situ respiration test. This test is performed by aerating the site until the
soil gas composition reaches steady state and then monitoring oxygen, carbon dioxide, and
contaminant. The results of a respiration test performed at the contaminated site can be compared
with background respiration data to obtain oxygen uptake rates. This information can be coupled
with mass load data for total utilizable organic compounds (determined in the laboratory) to
calculate the expected time to achieve cleanup.
Field tests, such as injection/withdrawal radius of influence tests, are required to determine
the spacing of the oxygen delivery systems. Other data required for the design of a bioventing system
include the location of potential receptors and logistical information such as availability of utilities
and access of the site to personnel.
Although bioventing will not be appropriate at every site, the low operating costs associated
with bioventing coupled with its ability to degrade both volatile and nonvolatile contaminants in situ
makes bioventing an attractive technology for site managers.
8-2
-------
REFERENCES
Aggarwal and Hinchee. 1991. Environmental Science Technology 25:1178-1180.
Brown, R.A. and J.R. Crospic. 1990. Water Pollution Control Federation Annual Conference,
October 6, Washington, DC.
Dupont, R., W. Doucette, and R. Hinchee. 1991. Assessment of in-situ bioremediation and the
application of bioventing at a fuel-contaminated site. In: R.E. Hinchee and R.O. Olfenbuttel, eds.,
In-Situ Bioreclamation: Applications and Investigations for Hydrocarbon and Contaminated Site
Remediation. Butterworth-Heineman, Boston.
Mark-Brown, N. 1993. Aspects of venting system design. Proceedings of Second International
Symposium for In-Situ and On-Site Bioreclamation. April 5-8, San Diego, California.
Nelson, C., R. Hicks, and S. Andrews. 1993. In-situ bioremediation: an integrated system approach.
In: J.H. Exner, D.E. Jerger, and P.E. Flathman, eds., Bioremediation: Field Experiences. Lewis
Publishers, Michigan. (In press)
Ong, S.K., R. Hinchee, R. Hoeppel, and R. Scholze. 1991. In-situ respirometry for determining
aerobic degradation rates. In: R.E. Hinchee and R.O. Olfenbuttel, eds., In-Situ Bioreclamation:
Applications and Investigations for Hydrocarbon and Contaminated Site Remediation. Butterworth-
Heineman, Boston.
R.E. Hinchee and S.K. Org. 1992. Air Waste Management Association 42(10): 1035-1312.
Sayles, G., R. Hinchee, R. Brenner, and R. Elliot. 1993. Documenting the success of bioventing in
deep vadose zones: a field study at Hill Air Force Base. Proceedings of Second International
Symposium for In-Situ and On-Site Bioreclamation. April 5-8, San Diego, California.
U.S. Air Force Center for Environmental Excellence. Test Plan and Technical Protocol for a Field
Treatability Test for Bioventing.
U.S. EPA. 1992. U.S. Environmental Protection Agency. A citizen's guide to bioventing. EPA/542/F-
92/008. Office of Solid Waste and Emergency Response, Washington, DC.
Vogel, C., R. Hinchee, R. Miller, and G. Sayles. 1993. Bioventing hydrocarbon contaminated soil
in a sub-arctic environment. Proceedings of Second International Symposium for In-Situ and On-Site
Bioreclamation. April 5-8, San Diego, California.
8-3
-------
Bioventing
An Aerobic Process to Treat
Vadose Zone Contaminated Soils
Ronald J. Hicks
Groundwater Technology, Inc
Concord, CA
and
Gregory Sayles and Richard Brenner
Risk Reduction Engineering Laboratory
US. Environmental Protection Agency
Cincinnati, OH
Outline
• Fundamentals
• Site Characterization
• Preliminary Design
Considerations
• Implementation
• Case Studies
• Cost Comparison
What Is Bioventing?
Definition
Forced air movement
through contaminated
vadose zone soils to supply
the oxygen necessary for
otherwise oxygen-limited
in situ bioremediation
8-4
-------
Conceptual Layout of Bioventing
Process with Air Injection Only
Cutoff Well to
Prevent
^Migrationto LowRateAir
Basement injection
(If necessary) ^
Ability to Control In Situ
Environment Vadose Zone
Parameter
Nutrient Concentration
O2 Concentration
Cell Concentration
PH
Temperature
Bioavailability
Moisture
Ease of Control
Low Medium High
X
X
X
X
X
X
X
Oxygen Carrier Mass
Requirements for Petroleum
Biodegradation
Oxygen Carrier
Aqueous Solutions
Air saturated
Nitrate (50 mg/L)
H2O2 (100 mg/L)
Air
Carrier/Hydrocarbon
400,000
90,000
65,000
13
8-5
-------
Results of Soil Analysis
Plot V2 at Tyndall ABB before and after venting.
Each, bar represents the average of 21 or more soil samples.
300
200
Concentration
(mg/kg)
100
AJtantmontu
Results of Soil Analysis
Building 914 soil samples at Hill AFB before and after venting.
Eaca bar represents the average of 14 or more soil samples.
20
Depth
(feet)
40
3362
Z3447
10
15
Depth
(meters)
5 20 100 1000
Hydrocarbon Concentration (mg/kg)
3 Btferta(!me*0t Inhlit* (jgggtnterrRedTtleBtlmeBS months, Hi Aftsr«tlm«a24 months
felfih ilr flaw r«t« chins«tolowtlrftowrito
Contaminant Removal
Biodegradation vs. Volatilization
Rate of
Removal
Total
Biodegradation+Volatilization
Air Flow Rate
8-6
-------
Advantages of Bioventing
• Employs concentrated source
of oxygen
• An in situ technology
• Destroys contaminant
• Treats volatile and nonvolatile
contaminants
• Low operating cost
r \ A
Site Characterization
•Contaminant(s) identity
• Cpntaminant(s) spatial
distribution
• Soil gas survey:
O2, CO2, TPH
Site Characterization
(cant.)
•Nutrients
•pH
• Moisture content
• Cation exchange capacity
(CEC)
8-7
-------
Soil Gas Survey
Measure
as a function of
position in
contaminated zone
> Low O2, high CO2 indicates
• Biodegradation activity
• Oxygen-limited rate
C>-Candidate site for bioventing
» High O2, low CO2 indicates
• Another factor, e.g., bioavailability, low cell numbers,
or nutrients, are limiting the rate
C>Not a candidate site for bioventing
Schematic Diagram of Soil Gas Sampling
Using the Stainless Steel Soil Gas Probe
Male Quick Couple
Female Quick Couple
Land Surface
^y— Tubing j
^Sampling Pump / Analyze,. °z
V^- AAn-Lg-A / \ TPH
^\ Soil Probe
"" '/ Extensions
^ -Soil Probe
Treatability
In Situ Respiration Test
Conduct the following in contaminated and in
background locations:
1. Aerate for 1-2 days
2. Monitor soil gas until steady state achieved
3. Shut off ah flow
4. Sample soil gas for O2, CO2, TPH, and He,
with time
5. Calculate rate:
Rate(%C>2/hr) = Rate (contaminated)
— Rate (background)
8-8
-------
Gas Injection/Soil Gas Sampling
Monitoring Point Used by Hinchee et al.
(1991) in Their In Situ Respiration Studies
3-Way
Varying
Pressure Gauge Q ^
— V-»T"^ — I
Air Source f T
X&atK. *
2.5 or More Feet
I
_L
0.5 to 2 Felt
-ILL
Gas
Sampling
L — Port
JRotometer
n Rotometer
Qjp Regulator
M Inert Gas
[ j Ground
**«* Surface
< — Small Diameter
Probe
•—Screen
sMssate"-
Sample Data Set for Two
In Situ Respiration Tests
Fallon NAS, Nevada
(Test WettAZ)
Time O2 CO2
(hours) (%) (%)
-23.5 0.05 20.4
0 20.9 0.05
2.5 20.3 0.08
5.25 19.8 0.10
8.75 18.7 0.13
13.25 18.1 0.16
22.75 15.3 0.14
27.0 15.2 0.22
32.5 13.8 0.14
37.0 12.9 0.23
46.0 11.2 022
49.5 10.6 0.16
Kenai, Alaska
(Test Well Kl)
Time
(hours)
-22.0
0
7.0
12.25
19.50
26.25
46.00
02
w>
3.0
20.9
11.0
4.8
3.5
1.8
2.0
C02
(?a
17.5
0.05
2.7
4.6
6.0
6.5
7.0
IUM««
•MTKU
1MMH,
Helium
_
1.8
1.4
1.4
1.3
1.0
0.9
U.AIfF«.e«hrltir
In Situ Respiration Test Results for Two
Bioventing Test Sites:
Fallon NAS, Nevada (Monitoring Point A2) and
Kenai, Alaska (Monitoring Point Kl)
^_. 0 10 20 30 40 50 60
8-9
-------
In Situ Respiration Test Results for
Monitoring Point SI,
Tinker AFB, Oklahoma
Oxygen 20.
and
Carbon
Dioxide
(X) 10
5.0
0 20 40 60 80 100 120
I., i ,11 . ~~-. Time (Hours)
to Situ Respiration Test Results for
Monitoring Point K3,
Kenai, Alaska
25
20
Oxygen
and 1S
Carbon
Dioxide 10
00
5-
Helium
10 20 30 40 50
_____ Time (hours)
Biodegradatipn Rate
Calculation
• Assume a stoichiometry, e.g.,
C6H14 + 9i/2O2-»- 6C02 + 7H2O
• Calculate conversion factor, e.g.,
forT=10°C, e=0.3
rate (mg/kg-day)=19.5 rate (%O2/hr)
8-10
-------
Typical Bioventing Rates
i Most sites:
Rate = 1-20 mg/kg-day
i.e., for rate = 10 mgAg-day
= 3,650 mg/kg-day
Soil Gas Permeability Test
1. Initiate air injection
2. Measure pressure at monitoring wells
at various distances
•With time and/or at steady state
3. Use "Hyperventilate" or similar
program to determine permeability
and radius of influence
K=permeability (cm2=Darcy)
Rj=radius of influence (cm)
Vacuum vs. In Time
Test 2, Bioventing Mot Test, Site 22-A20,
Beale AFB, California
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
ESi""" fa Time (minutes)
8-11
-------
Results of a Field Test to Determine Soil
Permeability to Air Flow, k, Sept. 16,1991
Monitoring Point F
14
12
10
Vacuum 8
Measured ,,
(Inches of °
water) 4
2
° 0.00 0.50 1.50 5.00 10.00 15.00 20.00
/
"
Design Approach
Required
Injection/
Withdrawal
Rate
(ft'/mln)
Blodcgradation Rate
(rag/kg-day)
Number of
Wells
Required
(wells/ft2)
Soil Gas
Permeability
Bioventing for
Remediation of Vadose
Zone Contamination
Case Study
8-12
-------
Initial Conditions
BTEXA=2,030 ppb
TPHC as Gasoline=l,800 ppb
TOGD=Phase Separated
Hydrocarbons
Chlorinated OrganicsE=4 ppb
BTEX=420 mg/kg
TPH as Gasoline=5,200 mg/kg
Total Oil and Grease=12,000
mg/kg
ABTEX-Benzene, Toluene, Ethylbenzene, and Xylene by EPA Method 602 Modified
BfiDL-Below Detection limits
°TPH»Total Petroleum Hydrocarbons by EPA Method 602 Modified
TOG-Total oil and Grease by EPA Method 413.2
^Analysis by EPA Method 602
fCFU-Colony Forming Units
Maximum
Ground Water
Concentrations:
Maximum
Soil
Concentrations:
Initial Conditions (com.)
Inorganic
Concentrations:
Bacterial
Counts:
i Ammonium, Nitrate, Nitrite,
Phosphate=BDLB
i Potassium=15.7-33.8 ppm
i pH=6.70-6.90
i Hydrocarbon Utilizers=
3.1xl03-1.7xl05 CFUVmL
i Background Heterotrophs=
1.2xl05-6.9xl05 CFU/mL
*BTEX-Benzene, Toluene, Ethylbenzene, and Xylene by EPA Method 602 Modified
BBDL-Below Detection limits
°TPH-Total Petroleum Hydrocarbons by EPA Method 602 Modified
TOG-Total Oil and Grease by EPA Method 413.2
EAnalysls by EPA Method 602
FCFU=Colony Forming Units
Conceptual Layout of Bioventing
Process with Soil Gas Reinjection
Optional
Makeup Blower
Air
[Soil Gas Monitoring}
8-13
-------
Soil Vent Bioremediation System
[Nutrients]
[Contaminated Soil| e
Oxygen Concentration in
Vadose Zone Before Venting
Distance (feet)
10 20 30 40 50 60 70 80
Depth
(feet)
10.
20.
30.
40-
SO-
60
70
Probe
Vent
Well
Oxygen Concentration in
Vadose Zone After Venting
Distance (feet)
10 20 30 40 50 60 70 80
8-14
-------
Injection vs. Withdrawal
I Advantages
Disadvantages
Injection
No off-gas treatment
Long gas residence time
Deep sites
Need extensive soil gas
monitoring
Near receptors
Shallow sites
Less control of gas flow
Withdrawal
Little soil gas monitoring needed Off-gas treatment likely
Can monitor off-gas Deep sites
Shallow sites
Greater control of gas flow
Initial Conditions
> Contaminant
• High M.W. petroleum
hydrocarbons hi unsaturated
zone
• Initial mass estimated at
11,000kg
> Geology
• Alluvial sands and gravels
Initial Conditions (com.)
•Treatability results
indicated significant
biodegradation with
aeration
•Vapor extraction pilot test
indicated 50' ROI
8-15
-------
Remediation System Schematic
To Atmosphere
Recovery Well
Water
Gallery
Nutrient Flume
Carbon Dioxide from Vapor
Extraction System
Parts Per
Minion 8
(thousands)
DJ FMAMJJ ASOND
Date
Carbon Isotope
Analysis
[Sample Location CO2(%) 513C
813C
Vapor extraction 1.27 -26.37 -24.3 to -30.1
MW-9 0.052 -18.14 -18.1 to-24.4
8-16
-------
f
J*
1
"
ir\
>
r
x r
\
IB \ J
rig v -«-
/
SliXSAY JS2S JLS3A
a
8-17
-------
SnKSLAY SXS XSSM
8-18
-------
Results
• 353 kg volatilized
Approximately 15,104 kg
removed biologically
(including saturated phase)
ReSUltS (cont.)
>813C values suggested
hydrocarbons were the
main source of CO2
>Site remediated in
approximately 3 years at a
total cost of approximately
$500,000.00
Remediation Results
Process
Phase separated product recovery
Volatilization
Biodegiadation*
Total
Total ground water recovered
and reinjected
Initial Contaminant Mass Estimate
Mass
Removed
1,510 Ibs
780 Ibs
33,300 Ibs
35,590 Ibs
8,835,598 gal
(>15 pore volumes)
25,800 Ibs
d from CO^ measurements from the vapor extraction system effluent. CO, measurements
were converted into contaminant mass removal rates using the following conservative assumptions.
1. Twenty percent of the carbon dioxide was produced from the Hodegradatlon of
native organic matter.
2. Forty percent of the biodegiaded organic carbon was evolved as carbon dkcdde.
flt*nlflMenl*iJ*ppnM<*i.ln:J.H.
8-19
-------
Cost/Performance Comparison for Various
Oxygen Systems
High Degree of Contamination
Costs
System
Air sparging
Water Infection
Venting system
Peroxide system
Nitrate system
Performance
System
Air sparging
iVatcr Injection
Venting system
tearidc system
titrate system
Capital
$35,000
$77,000
$88,500
$60,000
$120,000
Ibs/day Xsite
oxygea treated
6 41
8 73
4,000 60
190 100
211 100
Operation Maintenance
SSOO/moDth $l,200/month
$l,200/month $l,000/month
$l,500/month Sl.OOO/month
SlO.OOO/month Sl,500/month
$6,500/manth Sl.OOO/month
Utilization Time of S/lb oxygen
cfflcicncyX treatment used
70 858 days $25.80
50 1,580 days S28.62
5 132 days 53.82
15 330 days S18.60
12.5 335 days $22.06
8-20
-------
SUBSURFACE BIOREMEDIATION
John T. Wilson, Don K. Kampbell, Steven R. Hutchins
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK
and
Daniel F. Pope
Dynamac Corporation
Robert S. Kerr Environmental Research Laboratory
Ada, OK
SITE CHARACTERIZATION
Most commonly, a plume of contaminated ground water originates in a spill of a nonaqueous
phase liquid (NAPL) such as gasoline, diesel oil, or jet fuel. A small fraction of the total
contaminant mass exits in the ground water. As a result, monitoring wells greatly underestimate the
mass of contaminant subject to remediation.
At present, the acquisition, extraction, and analysis of core samples is the only technique
available to quantify the mass of an NAPL contaminant in the subsurface. Soil gas screening
techniques can locate the spill both horizontally and vertically. Then a continuous series of core
samples should be taken across the entire interval contaminated with NAPL. Cores should be
extracted in the field, rather than shipped back to the laboratory for extraction.
In addition to the location of the NAPL source area, design or evaluation of subsurface
bioremediation requires information on lithology of the site and the local pneumatic or hydraulic
conductivity. This information traditionally is obtained by coring a site and conducting aquifer tests
in wells. Cone penetrometers are developing as a rapid and inexpensive alternative to traditional
techniques. They can rapidly and accurately map lithological features and determine local hydraulic
conductivity. Hydraulically driven soil gas samplers also are gaining wide application. They greatly
reduce the labor involved in soil gas sampling and allow sampling at greater depth.
The role of site characterization is illustrated in a case study. A spill from an underground
storage tank was flushed with hydrogen peroxide and mineral nutrients for 3 years. When the
concentration of benzene, toluene, ethylene, and xylene (BTEX) compounds in monitoring wells
9-1
-------
approached acceptable levels, the site owner petitioned for closure. Significant concentrations of
alkylbenzenes (BTEX) remained in core material after remediation;, ground water moving past the
spill, however, was not contaminated. Apparently, the residual contamination was sequestered in
material that was not permeable to water.
NATURAL (INTRINSIC) BIOREMEDIATION
Intrinsic bioremediation is an important process for destruction of contaminants in the
subsurface. It deserves to be considered as part of the comprehensive plan to manage contaminants
at hazardous waste sites. At present, intrinsic bioremediation suffers from a lack of regulatory
credibility, largely because of inadequate or incomplete site characterization and laboratory studies.
A complete assessment of intrinsic bioremediation includes the following activities:
1. Locate areas with oily-phase contamination.
2. Determine the trajectory of ground water flow.
3. Install monitoring wells along the plume.
4. Determine the apparent attenuation along the plume.
5. Correct apparent attenuation for dilution and sorption.
6. Assume corrected attenuation is bioattenuation.
7. Confirm bioattenuation from the stoichiometry of electron acceptors and donors.
8. Estimate the elapsed time to monitoring wells.
9. Calculate rate constants from the elapsed time and bioattenuation.
10. Confirm rates with laboratory microcosms.
11. Extrapolate extent of bioattenuation to the point of compliance to determine if the
extent of bioattenuation is protective.
AIR SPARGING OR BIOSPARGING
Air sparging or biosparging refers to the technique of injecting air below the water table.
The name implies that the technique works by enhanced dissolution of the NAPL into the sparged
air. Actually, the technique is an effect mechanism to oxygenate ground water in contact with the
NAPL. Most of the removal is due to aerobic biodegradation of the NAPL.
Biodegradation supported by sparging can remove BTEX compounds from ground water and
NAPLs quickly. After the aromatic compounds are removed, residual hydrocarbons might be
persistent.
9-2
-------
Air sparging is not appropriate for every site, and it must be managed carefully. After
contact with the NAPL, the sparged air often exceeds the lower explosive limit and can be a hazard
in confined spaces.
REFERENCES
R.D. Morris, R.E. Hinchee, R. Brown, P.L. McCarty, L. Semprini, J.T. Wilson, D.H. Kampbell, M.
Reinhard, EJ. Bouwer, R.C. Borden, T.M. Vogel, J.M. Thomas, and C.H. Ward. 1993. In situ
bioremediation of ground water and geological material: a review of technologies. Available from
Kay Cooper, Dynamac, Inc., R.S. Kerr Laboratory, Ada, Oklahoma.
9-3
-------
SUBSURFACE BIOREMEDIATTON.
John T. Wilson, Steven R. Hutchins, and
Don H. Kampbell, U.S. Environmental
Protection Agency
Daniel Pope, Dynamac Corporation
R.S. Kerr Environmental Research Laboratory,
U.S. Environmental Protection Agency,
Ada, OK
NEW APPROACHES FOR SITE CHARACTERIZATION
DEFINITION OF THE PROBLEM
9-4
-------
NONAQUEOUS PHASE LIQUIDS
NAPLS, LNAPLS, DNAPLS
The NAPLs define the source area
of the ground water plume.
To the extent feasible, these
materials should be removed
by free product recovery, befpre
bioremediation proceeds.
SITE CHARACTERIZATION REQUIREMENTS
SPECIFIC TO THE SUBSURFACE
Goals:
Map the contaminant mass in three dimensions.
Determine the co-distribution of
contaminant
and hydraulic or pneumatic conductivity
PROBLEMS WITH MONITORING WELLS
They cannot estimate
contaminant mass in NAPLs
They cannot estimate
contaminant mass adsorbed to solids
They do not sample contaminant
mass above the water table.
9-5
-------
COMPARISON OF CONTAMINANT MASS IN
GROUND WATER TO TOTAL CONTAMINANT MASS
At a Pipeline Spill in Kansas:
Mass in Mass in
Ground Water Subsurface
Benzene 22 kg
BTEX 82 kg
TPH 115 kg
320 kg
8,800 kg
390,000 kg
WHEN TOTAL CONTAMINANT MASS IS UNKNOWN
Cannot estimate requirements for electron
acceptors.
Cannot estimate requirements for nutrients.
Cannot determine time required for cleanup.
RELATIONSHIP BETWEEN FREE PRODUCT IN
MONITORING WELLS AND CONTAMINANT MASS
IN AQUIFER
Position and quantity in wells
does not relate to position
and quantity in aquifer.
Amount of free product related
to location of water table.
9-6
-------
RELATIONSHIP BETWEEN FREE PRODUCT IN
MONITORING WELLS AND CONTAMINANT MASS
IN AQUIFER
Free product is greatest when water table
is low.
Free product can disappear when water table
is high.
DRILLING AND SAMPLING TECHNIQUES
Conventional techniques
Hollow-stem augers
Split-spoon samplers
New techniques
Cone penetrometer
Geoprobe
STATE OF PRACTICE FOR DETERMINING
CONTAMINANT MASS
Subsample cores in the field for extraction
and analysis of specific contaminants
and total petroleum hydrocarbons.
Cores can'be screened with a hydrocarbon
vapor analyzer.
9-7
-------
Auger Column
Barrel Sampler
Non-Rotating
Sampling Rod
Auger Head
CONE PENETROMETERS
Advantages:
Fast and relatively inexpensive.
Measure properties on an appropriate scale,
Disadvantages:
Don't work well in geological materials
with boulders or
cobbles.
Restricted to shallow depths.
INFORMATION PROVIDED BY CONE PENETROMETERS
Lithology inferred from tip and sleeve
resistance.
Electrical conductivity.
Water samples for analysis of contaminants.
Local hydraulic conductivity.
9-8
-------
V
r
E -
€-30 -
-40 -
-50 -
-60
15 10 S 0 750 15000 2460.
Sleeve Friction Tip Friction
Stress Stress Ratio
(psl) (psl) (%)
SEPItM
POBDOS PHAER
€
0
1 1 1 1 1
— Slalic —
x-Pore
- Pressure-
"V©-
4f
M
3
=} — ®-
~-r
nkr=pP
40 80 1<
Pore
Pressure
(psl)
*
T «=•
I *
Sandy Soil 2 2g
1 jg
~~T~ &
Organic Clay Q
to
Sand <;n
-&
I25
Sandy Clay £
i °~
>0 0
. ..,,..•! . ..,...,, . .......
_ ©
1 1 10 1
Time (mln)
Depth = 45 ft
1 1
- ® '
_ _
.
. ..i...,i i . ,.i...
11 10 11
Time (mln)
Pore Pressure
Dissipation Tests
)0
10
9-9
-------
GEOPROBE
Advantages:
Very fast and inexpensive
Leaves a small borehole
Disadvantages:
Restricted to shallow
unconsolidated materials.
Does not give information
on lithology.
INFORMATION PROVIDED BY A GEOPROBE
Soil gas samples for analysis.
Water samples for analysis.
Small core samples for analysis.
CASE STUDY
Application of site characterization
techniques to evaluate subsurface
bioremediation.
9-10
-------
WHAT CAN BIOREMEDIATION ACHIEVE?
Remove all components of a spill
from the subsurface?
Remove hazardous components of
a spill from the subsurface?
WHAT CAN BIOREMEDIATION ACHIEVE?
Remove hazardous components of
a spill from ground water?
Remove hazardous components
from pumped ground water?
CASE STUDY
Spill of oily liquids from
a temporary underground
holding tank
Shallow water table aquifer
in an industrial area
Fluvial depositional
environment.
9-11
-------
TECHNOLOGY IMPLEMENTED
Ground water was circulated
in a closed loop.
Added hydrogen peroxide,
ammonia-N, and phosphate
from 7/89 to 3/92.
Reduction of Benzene in Ground Water
Well
MW-1
MW-8
MW-2A
MW-3
RW-1
Before
During
After
-(ug/liter) —
220
180
7
11
<1
<1
130
11
5
2
<1
16
0.8
2
<1
9-12
-------
Reduction of BTEX in Ground Water
Well
MW-1
MW-8
MW-2A
MW-3
RW-1
Before During After
- (ug/ liter) —
2,030 164 <6
1,800 331 34
? 1,200 13
1,200 820 46
<1 2 <1
J
j
T
i
£
(a
ABC D E F
5300 J 1 I 1 1 U 5300
Clay j,*r Sand
5290 - ^^fY^^ ~* ^^
-— -— "^^^"^ \ [^"Source of Hydrocarbons M
o
£f j* Water Table £
§J Residual Hydrocarbon •—
to O
•3
1
5270 - - 5270
Sandy Aquifer
«rtO ..•.,, - - 5260
\
Concentration of Contaminants
Remaining at Most Contamined Level
Bore
B
C
D
E
TPH
BTEX
Benzene
(mg/kg)
1,767
156
1,180
156
0.8
3.5
260
3.5
<0.2
<0.2
4.3
0.06
9-13
-------
RELATIONSHIP BETWEEN GROUND
WATER AND OILY PHASE CONTAMINATION
The reduction in concentration in
ground water equivalent to the
reduction in weathered oil.
Not all the oily phase weathered.
Is it in contact with ground water?
20
IS
16
14
12
10
8-
6
4-
2-
200 400 600 800 1000 1200
TPH mg/kg
RELATION BETWEEN PUMPED WELLS
AND PASSIVE MONITORING WELL
Why didn't the pumped well
RW-1 contain contaminants?
How can we estimate the
effects of dilution in pumped
well?
9-14
-------
WILL A PLUME OF CONTAMINATED
GROUND WATER RETURN?
Is the electron acceptor
supply greater than the
demand?
What is mass transfer from
residual oily phase to
moving ground water?
Potential Oxygen Demand
Bore
A
B
C
D
E
F
Above
Within
Below
(mg O2 /kg day) —
<4
7.4
15.5
>30
>36
>34
23.5
6.0
<3
5.7
713
21.0
Conditions during Active Remediation
Parameter
dissolved oxygen
hydraulic gradient
ground water flow
travel time
BOD supported
Active Remediation
470 mg/ liter
0.097 m/m
2.4 m/day
2 0 days
20 mg/ liter day
9-15
-------
Conditions after Active Remediation
Parameter
dissolved oxygen
hydraulic gradient
ground water flow
travel time
BOD supported
Active Remediation
5.5 mg/ liter
0.0012 m/m
0.3 m/day
1,500 days
0.004 mg/liter day
Contrast Before and After
Active
470 mg/liter
0.097 m/m
2.4 m/day
20 days to RW-1
20 mg/liter day
Afterwards
5.5 mg/liter
0.0012 m/m
0.03 m/day
1,500 days
to monitoring
0.004 mg/liter day
9-16
-------
A
B
D
9-17
-------
WILL THE PLUME RETURN?
TOO CLOSE TO CALL!
How long would it take
for a plume to develop
and reach the monitoring
wells?
WILL THE PLUME RETURN?
How long will it take water
to move all the way across
the spill to the
monitoring well under
ambient conditions?
WILL THE PLUME RETURN?
Has active treatment
weathered the spill to
the point that intrinsic
bioremediation prevents
development of a plume?
9-18
-------
NATURAL OR PASSIVE BIOREMEDIATION
The preferred description is
INTRINSIC BIOREMEDIATION
All bioremediaton is "natural."
Neither the microorganisms nor
the microbiologists are "passive."
INTRINSIC BIOREMEDIATION
Determination is site specific.
Requires extensive site characterization.
Burden of proof is on the proponent, not
the regulator.
PATTERNS OF INTRINSIC BIOREMEDIATION
Limited by supply of a
soluble electron acceptor.
Aerobic Respiration
Nitrate Reduction
Sulfate Reduction
9-19
-------
PATTERNS OF INTRINSIC BIOREMEDIATION
Limited by biological activity.
Iron Reduction
Methanogenesis,
Sulfate Reduction
PATTERNS OF INTRINSIC BIOREMEDIATION
Limited by supply of electron donor.
Reductive Dechlorination
INITIAL ELEMENTS OF A QUANTITATIVE
ASSESSMENT OF INTRINSIC BIOREMEDIATION
1) Locate areas with oily phase
contamination.
2) Determine trajectory of
ground water flow.
3) Install monitoring wells
along plumes.
9-20
-------
ADDITIONAL ELEMENTS OF A
QUANTITATIVE ASSESSMENT
4) Determine apparent attenuation
along plumes.
5) Correct apparent attenuation
for dilution or sorption.
6) Assume corrected attenuation
is bioattenuation.
7) Confirm bioattenuation from
stoichiometry of electron acceptors
or donors.
FINAL ELEMENTS OF A
QUANTITATIVE ASSESSMENT
8) Estimate elapsed time
to monitoring wells.
9) Calculate rate constants
from elapsed time
and bioattenuation.
10) Confirm rates with
laboratory microcosms.
CASE STUDY OF
INTRINSIC BIOREMEDIATION
SLEEPING BEAR DUNES
NATIONAL LAKE SHORE
9-21
-------
Pewtr Pol*
o e 10 15
M*t«r*
I Currant
PUtU Mlvir
Currant
05 10 15
M*t*r*
9-22
-------
LOCATE AREAS WITH
OILY PHASE MATERIAL
Plumes usually do not
attenuate in the presence
of oily phase contamination.
Goal is to determine the
boundary of oily phase
contamination.
LOCATE AREAS WITH
OILY PHASE MATERIAL
Often can be conveniently
located by a soil gas survey.
Confirm with core analysis.
DETERMINE TRAJECTORY OF
GROUND WATER FLOW
The direction of flow, controlled
by the hydraulic gradient
measured from water table elevations,
The velocity of flow is the product
of the hydraulic gradient
and the hydraulic conductivity as
determined through an aquifer
test.
9-23
-------
VARIATION IN GROUND WATER FLOW
Most plumes vary in direction
and velocity of flow.
Plumes in upland landscapes
tend to be less variable.
VARIATION IN GROUND WATER FLOW
Plumes near rivers or estuaries
tend to be more variable.
At a minimum, quarterly monitoring
for a year is required.
Several years of monitoring
is better.
20 .10 -40 50 00 70 SO 90 100 110 120 1.10 140 150 100
Klapscd Time (weeks)
9-24
-------
INSTALLATION OF MONITORING WELLS
Wells should be installed
along a flowpath near the
centerline of the plume.
Wells should be installed
across the vertical extent
of the plume.
Sleeping Bear Dunes NLS
Former Casey's Canoe Livery
21B-
216-
214-
212
210-
2OB-
2O6-
Land Surface
Platte
River
"~T 1 1 1 1 1 1 1 1 1 ]
5 1O 15 2O 25 3D 35 4O 45 SO 55
Distance Along Flow Path (Meters)
Vertical Exaggeration 2X
9-25
-------
VERTICAL DISTRIBUTION OF MATERIALS IN GROUND WATER
SEVENTY FEET DOWN GRADIENT OF THE SPILL AREA
EleTatlon
AMSL
(feet)
587-584
584-581
581-578
578-575
575-572
572-569
569-566
Total
BTEX
0.17
2.0
0.041
0.086
0.037
0.00006
0.00006
Methane
(mg/Uter)
L55
3.1
0.56
0.47
0.087
0.035
0.0006
Oxygen
0.8
0.4
0.7
0.7
0.5
0.7
13
^ *
VERTICAL DISTRIBUTION OF MATERIALS IN GROUND WATER
SEVENTY FEET DOWN GRADIENT OF THE SPILL AREA
Ekntion
AMSL
(feel)
587-584
584-581
581-578
578-575
575-572
572-569
569-566
Total
BTEX
OJ.7
2.0
0.041
0.086
0.037
0.00006
0.00006
Nitrate
' <0.05
0.10
<0.05
0.2
03,
0.4
<0.05
Sulfate
liter- —
4.8
<0.05
S3
18.4
16.2
US
6.0
IrooII
33
52
5.1
3.0
0.17
0.05
0.05
DETERMINE APPARENT ATTENUATION
Collect monitoring data over
time to estimate
apparent attenuation.
Apparent attenuation usually
has a strong contribution
from simple dilution and sorption.
9-26
-------
10-
* H
.2 0.1-
I
•**
s
i
o
0.01-
0.001-
0.000
Toluene
30 40 50 60 70 80 90 100 110 120 130 140 150 160
Elapsed Time (weeks) >/
10
I
g
i-
0.1-
0.01-
|
£ 0.001
0.0001
Benzene
30 40 50 60 70 80 90 100 110 120 130 140 150 160
Elapsed Time (weeks)
10
J 1-
E
^ 0.1-
-| 0.01-1
i
£ 0.001-
0.000
A.-
Methane
«
0 0
A A A A
_ loSpiU
O 30F«t
X 70 Feet
50 60 70 80 90 100 110 120 130 140 150 160
Elapsed Time (weeks)
9-27
-------
CORRECTING ATTENUATION FOR
DILUTION OR SORPTION
Identify a component of the
plume that can serve
as a tracer.
A GOOD TRACER
-is not biodegradable in
the absence of oxygen.
A GOOD TRACER
-is present in the plume
source area at concentrations
at least 100 times
its detection limit.
9-28
-------
A GOOD TRACER
-has the same sorptive properties
as the regulated compounds.
Apparent Attenuation of 2,3-Dimethylpentane
in the Plume of Contaminated Ground Water
Date
7/92
11/92
In Spill
30 feet
70 feet
(ug/ liter averaged over 21 feet)
23.4
26.6
7.30
6.24
1.64
1.77
CORRECTING ATTENUATION FOR
DILUTION OR SORPTION
To correct apparent attenuation
for dilution or sorption,
divide the concentration of
contaminants by the
concentration of the tracer.
9-29
-------
STOICHIOMETRY OF ELECTRON ACCEPTORS
AND ELECTRON DONORS
After correction for dilution, the
concentration of biodegradation
end products should balance the
concentration of organic materials
destroyed.
Methane Production and Electron Acceptor
Consumption in the Most Contaminated Interval
Compound
Methane
Nitrate-N
Sulfate
Iron II
Oxygen
Up
Gradient
Down
Gradient
BTEX
Consumed
(mg/liter)
0.08
15.3
20.0
3.5
2.4
29.8
<0.05
<0.05
27.8
<0.1
39
14
4.2
1.1
0.8
Forty-two mg/liter BTEX was actually consumed.
STOICHIOMETRY OF ELECTRON ACCEPTORS
AND ELECTRON DONORS-SOURCES OF ERROR
Methane might be lost to volatilization.
Iron may precipitate as iron (II) sulfide
or iron (II) carbonate.
Natural organics may exhibit an electron
acceptor demand.
9-30
-------
CALCULATING RATE CONSTANTS
When limited by biological activity,
rates are apparently pseudo-first order
on time.
When limited by supply of electron
acceptor, rates are apparently
pseudo-first order on length of travel,
which often is proportional to time.
ESTIMATING ELAPSED TIME
Determine the time of travel
from the edge of the oily phase
material to the monitoring well, or
from well to well along a flow path.
ESTIMATING ELAPSED TIME
Calculate elapsed time from the
flow velocity as predicted from
the hydraulic gradient and
hydraulic conductivity,
or conduct a tracer test.
9-31
-------
LABORATORY CONFIRMATION
When bioremediation is limited
by biological activity, it is
often possible to duplicate
the kinetics of degradation
in the laboratory.
LABORATORY CONFIRMATION
If bioremediation is limited
by the supply of electron acceptor,
laboratory kinetics grossly
overestimate field kinetics.
COMPARISON OF FIELD AND LABORATORY
MICROCOSM RATE CONSTANTS
Distance Benzene Toluene Ethyl-
from spill benzene .
(feet) — percent depleted per week—-
Field rate, corrected for dilution or sorptlon
30 -0.6 42 4.6
70
-0.9
17
•S.2
Laboratory microcosms, corrected for abiotic
losses, after lag phase
0 0.1 30 0.2
30
70
• 0.4
-0.1
6.2
7.9
0.7
10
9-32
-------
COMPARISON OF FIELD AND LABORATORY
MICROCOSM RATE CONSTANTS
Distance Toluene m+p- o-Xylene
from spill Xylene
(feet) —percent depleted per week-
Field rate, corrected for dilution or sorption
30 42 5.9 8.5
70 17 4.2 S3 •
Laboratory microcosms, corrected for abiotic ,
losses, after lag phase
0 30 0.2 <0.1
30
70
6.2
7.9
0.7
0.3
0.8
0.4
COMMON ERRORS IN ESTIMATES
OF INTRINSIC BIOREMEDIATION
Oxygen is the only electron
acceptor considered.
The contaminant being modeled
is the only electron donor
considered.
AIR SPARGING AND BIO-SPARGING
Air Sparging and Bio-sparging are the most
rapidly growing applications of subsurface
bioremediation.
9-33
-------
Air Sparging
The Problem
Contaminants below the
water table
Contaminants below
the water table
• Pump & Treat ineffectual -
low solubility of oily phase
• Less than 5% ever enters
solution
• Remainder sorbed to solids
or free phase
9-34
-------
Contaminants below the
water table
• Soil Venting ineffectual
- water saturated pores
• Bioremediation costly
with hydrogen peroxide
Soil Vapor Extraction
• Indirectly stimulate
biodegradation of dissolved
contaminants
• Increased oxygen content in
vadose zone
• Increased diffusion from
vadose zone to GW
Soil Vapor Extraction
• Direct treatment of saturated
zone contaminants
• Generally requires that site
be effectively dewatered so
air flow can be induced
9-35
-------
Need for efficient,
inexpensive delivery of
oxygen to saturated zone
***AIR SPARGING***
Air Sparging
Injection of air under
pressure below the
water table
Creates transient air
filled porosity
Monriarinp
Vapor Extraction Atr Sparger
Well Well
Monitoring
Probe
Air Sparging System
9-36
-------
Air Sparging
Minimum pressure to
displace water
That needed to
overcome resistance of
soil matrix to air flow
Pressure Required
Function of water column
height to be displaced
Flow restriction (air/water
permeability) of soil matrix
Pressure Required
When "break-out" pressure
achieved
Air enters the soil matrix
Travels horizontally/vertically
through soil, displacing water
Exits into vadose zone
9-37
-------
Air Sparging
Enhances biodegradation by
increasing oxygen transfer
Enhances physical removal
by volatile (vapor phase)
extraction
Air Sparging
Can treat volatiles/organics
in GW aquifers by volatile
removal, biodegradation
Air Sparging
Extensively used in
Germany since 1985
Successfully introduced
in the US in 1990
9-38
-------
Air Sparging
Earlier systems injected air
into water column in well
No direct contact with
formation matrix
Air Sparging
Now, injection pressure
> hydraulic head
Well contains no water
Air directly injected into
formation
Differences Between Old & New Air
Sparging Technologies
Fonnalion
Air Bubbles
•:••:•:••><$
^f~f. •»
m
$$
tt£
l*Ett
Old
Air Sparging
(In Well Sparging)
*j* ?j ""*"
•J**flPli
m
• Injecied Column
I-'ormaiion
Air Bubbles
New
Air Sparging
9-39
-------
Effects of Air Sparging
• Enhanced oxygenation
1 Enhanced dissolution
1 Volatilization
1 GW stripping
1 Physical displacement of GW
Enhanced Oxygenation
• Replenishes oxygen depleted by
chemical/biological processes
• Normal replenishment relies on
diffusion from water table surface
• Sparged air, distributed throughout
aquifer, has short diffusion path
• Enhanced oxygenation stimulates
biodegradation
Enhanced Dissolution
Injected air causes turbulence in
pores
Mixes water, adsorbed contaminants
Enhances partitioning into water
Normal water/soil contact static,
dissolution diffusion limited
9-40
-------
Enhanced Dissolution
• Enhanced dissolution beneficial
if GW collected
• Detrimental if contaminants not
captured, treated by in-situ
stripping
• Dissolution can help promote
biodegradation
Volatilization
Adsorbed contaminants
evaporate into air stream
Carried into vadose zone
Extent of volatilization
governed by vapor pressure
Volatilization
Prevented in saturated
zone - no air phase
Can remove significant
mass of contaminants
9-41
-------
Ground Water Stripping
Volatiles with high
Henry's Law Constant
volatilize from water
into air stream, removed
Physical Displacement
• Water can be rapidly displaced at
very high air flow rates
• Observed in air-rotary drilling
• Contaminated displaced water
spreads contamination in any
direction
• May not be captured by existing
GW systems
I Enhanced Oxygcnaiion
Enhanced Panitioning
I Volatilization
iGroundwatcr Stripping
_Oplimum Operating Rangc_
Physical Displacement
High
_>. Air Flow Rate. SCFM
( Generally Beneficial Effect
i. Potentially Detrimental Effect
» Generally Detrimental Effect
Effects of Air Flow as a Function of Air Flow Rale
9-42
-------
Air Flow Rates
Too low air flow will not
effectively remove volatiles
May increase ground-water
concentrations
Too high flow can spread
contamination
Optimizing air flow will maximize
mass removal, minimize potential
contaminant spread
Comparison Of Air
Sparging To Other
Sources Of Oxygen
• Soil Venting - Low
contact
• Injected Peroxide -
Expensive, unstable
OXYGRN AVAII,ABII.ITY,UVDAY
Air Sparging
Hydrogen PcroxklcUOOOppm)
Flow Uliliyititnt
236
590
IIR2
295
590
56
140
280
70
140
9-43
-------
Removal Of Contaminants
In Air From Soil Matrix
> 1 mm Hg vapor pressure
Removal Of Contaminants
In Air From GW
Henry's Law constant
greater than 10
~5
HENRYS CONSTANT KOR SELECTED HYDROCARBONS
Constituent
CydohexMic
Benzene
Eih)lbcnzcnc
Toluene
X>knc
Naphthalene
Phcnanlhrcnc
Henry's Constant, KH
(alm-m3-mole-l}
1.9 xlO2
5.6x10-3
8.7x10-3
6.3 x lO-3
5.7x10-3
4.1 x 10-4
2.5 x 10-5
9-44
-------
Air Sparging
Primary And Secondary
Removal Mechanisms
SITE AND PILOTTEST DATA NEEDED FOR DESIGN
Data
Impact on Design
Lilhological Barriers
Vertical Extent of Contamination
Horizontal Extent of Contamination
Volatility of Contaminant
Sparge Radius of Influence
Optimal Flow Rates
Vent Radius of Influence
Vacuum/Pressure Balance
Vapor Levels
Feasibility/Sparging Depth
Sparging Depth
Number of Sparge Wells
Vapor Conlrol (Venting)
Well Spacing/Flow Requirement
Compressor Size
Well Spacing
Blower Size/Well Placement
Vapor Treatment
Air Sparging
Disadvantages
Flow away from
injection point
Hard to maintain control
9-45
-------
Air Flow Paths
1 Injected air travels horizontally,
vertically
• Flow impedance by lithological
barriers blocking vertical air flow
Channelization - horizontal air flow
captured by high permeability
channels
Small permeability differences can
change flow paths
Inhibited Vertical Air Flow Due to
Impervious Barrier
n
55&S8SfcB8^^
Contaminated Soil
Dissolved Particles
inant Migration
.
^^.^^.^^^^^.s^.^^\\^^^^.\^^.s^^^
Ai^Contaminant Mi^raliun
.
NS^^\^^^.^.^.^.^s^^^^^^^
• SS\\\\\\\\N\NN\N\\
\$p;S
k\\S\\\\\\\\S\N\\XXSNNN\S.t
•svw>.\xs.N\ssss>.'s.N\\sss.xx\'*
Channeled Air Flow Through Highly
Permeable Zone
. 9-46
-------
Air Flow Paths
Channeled air flow may
cause uncontrolled spread of
contamination
Lithological profile should be
developed before system
installed
Pilot test
Spreading of Dissolved
Contaminants
• Injection pressure, flow
• Water table mounding
Injection Pressure
• Minimum pressure must
overcome water column
pressure
• 1 psi for every 2.3 feet of
hydraulic head
• Above minimum, water
injected into aquifer
9-47
-------
Effect of Injection Pressure on Air Flow
3*
g| to
|S u
I idj Mcuuremcnu
Turbulent Mow
(Potential for Water
Displacement)
0.0 2.0 4.0 6.0 H.O 10.012.0 14.0 16.0 ] 8.0 20.0
Ratio of Horizontal Radius vs Sparge Depth
Water Table Mounding
• Air sparging raises
water table
• GW flows away from
mound
Water Table Mounding
' Mounding produced by sparging
caused by displacement of water
with air
• Flow away from mound may not be
induced because net density of water
column is decreased
Contaminants may be stripped
before significant migration
9-48
-------
WATER TABLE MOUNDING AND COLLAPSE
Depth to Water (it) @
Well 8 - Distance from Static Sparging
Sparge Point Water Level Water Level
MW-7 5 6.46 4.09
SE-1919 6.42 6.20 6.93
S-2629 6.71 6.55 6.96
NE-13 13 6.52 6.1!
5 Mil, 10 Min
After After
10.03 6.96
6.54
6.77
7.44 6.75
Accelerated Vapor Travel
• To basements, other low
pressure areas
• Use vent system to
capture vapors
Ground Water Chemistry
• Oxidize Fe, Mn
• CO2 may precipitate
CaCO3
9-49
-------
Summary
Applicable Contaminants
• Volatile, relatively
insoluble
• Removal as vapor
Applicable Contaminants
• Biodegradable
• Removal by
biodegradation
9-50
-------
Geology of Site
Relative homogeneity
Strata above sparging
point > permeability
Geology of Site
Permeability
Ratio of horizontal to
vertical permeability
<2:1 OK, even if
permeability relatively low
(>10~5 cm/sec)
Geology of Site
Permeability
•IfH:V>3:l
«Permeability should
be >10"4 cm/sec
9-51
-------
Sparge System Depth
• Minimum depth 4 feet
• Saturated thickness
required to force
cone-out from injection
point
Sparge System Depth
Maximum depth 30 feet
Difficult to predict flow paths
Small permeability differences
create major variations
Difficult to contain/capture sparged
air
Sparge System Depth
• Sufficient unsaturated
zone depth for SV
• > 4 feet to water table
9-52
-------
Site Characterization
Contaminant Mass
Distribution
• Vertical for location of sparging
points
• Horizontal for complete coverage
• Downgradient plume for
monitoring, remediation
Site Characterizaton
Potential Receptors
Soil venting for vapors
GW extraction/barriers
for dissolved
contaminants
Pilot Tests
• Air sparging radius of
influence
• Soil venting radius of
influence*
• Combined sparge/vent test*
*Where vapors are a concern
9-53
-------
Pilot Test Measurements
• Vacuum/pressure vs. distance
• Volatile concentrations
• Carbon dioxide/oxygen
levels
• DO levels in GW
• Water levels
Volatile Concentrations
Which compounds
removed
Carbon Dioxide/
Oxygen Levels
Indicator of biological
activity
Before, during, after
pumping
9-54
-------
Carbon Dioxide/
Oxygen Levels
Usually depressed O2,
elevated CO2 before
Rise during test indicates
effectiveness
Drop after test indicates
biological activity rates
Dissolved Oxygen In GW
• Indicator of sparging
effectiveness
• Often < 2 mg/1 in
contaminated zone
Water Levels
Mounding effect
9-55
-------
Air Sparging Systems
•Well
• Compressor/Blower
• Monitoring System
• Heat Exchanger
• SVE System
• Vapor Treatment
• GW Control
Air Sparging Well
• 10-15 ft intervals
• Steel, above 15 psi
• — £^ J>pan;c Screen (I-21)
Nested Sparge Well
9-56
-------
Compressor/Blower
• 10-20 cfm/well
• 1-3 X breakout pressure
• Ainwater 10-20:1
Filter
Remove oil,
particulates, moisture
Monitoring System
Well to measure water table
elevation
DO, contaminants, pressure
Vapor probes for volatiles,
pressure/vacuum
9-57
-------
.VjfxwPmhc
(.04 SM)
Vapor Probe
" (.04 Slot)
Monitoring Point for Sparging Systems
Heat Exchanger
For PVC systems
Soil Vacuum System
• To capture volatiles
• Maintain net negative
pressure
• Total flow 2X sparge
flow
9-58
-------
Vapor Treatment
• For captured volatiles
• Thermal
• Biological
Ground Water Control
Contamination
containment
*U.S. GOVERNMENT PRINTING OFFICE: 1993 -7 52-32 I/
9-59
-------
-------
-------
m
-a
o
1
s
o o m c
=V CD 3 3
2. 3 3- j*
- CD o
*y MIS
"n =;* _ «•*•• iX »-*•
•U5
=• CD
CO (O
CD
CO
CD
83 CD
CD rt
l§
33 >
CD CO
CO CD
CD 3
if
its
------- |