United States
Environmental Protection
Agency
Robert S. Kerr Environmental
Research Laboratory
Ada, OK 74820
Research and Development
EPA/600/S2-90/006 Apr. 1990
Project Summary
Enhanced Bioremediation
Utilizing Hydrogen Peroxide as a
Supplemental Source of Oxygen:
A Laboratory and Field Study
Scott G. Huling, Bert E. Bledsoe, and Mark V. White
Remedial actions at hazardous
waste sites Involving in-situ treatment
are widely recognized as a preferred
treatment option. Bioremediation, a
treatment technology which can be
implemented in-situ, utilizes available
oxygen to metabolize organic con-
taminants. Laboratory and field scale
studies were conducted to Inves-
tigate the feasibility of using hydro-
gen peroxide as a supplemental
source of oxygen for the bloremedia-
tion of an aviation gasoline fuel spill.
Field samples of aviation gasoline-
contaminated aquifer material were
artificially enhanced with nutrients to
promote microbiological degradation
of fuel carbon In laboratory columns.
Oxygen provided from hydrogen per-
oxide decomposition was utilized
biologically in the columns. However,
the rapid rate of hydrogen peroxide
decomposition at 100.0 mg/L resulted
in the production of oxygen gas.
Reduced rates of oxygen consump-
tion during this period Indicated that
microbial inhibition may have
occurred.
A mass balance of the fuel carbon
Indicated that approximately 36.0% of
the initial mass leached out in the
aqueous phase, 10.0% remained, and
54.0% degraded. The ratio of oxygen
consumed to aviation gasoline
degraded was greater than that
predicted by the ideal stoichiometrlc
conversion. Hydrogen peroxide
breakthrough in the column effluent
never exceeded 11.0% of the influent
concentration which was increased
up to 200.0 mg/L
Field studies confirmed that there
was a measurable increase of
oxygen in the soil gas in the area
where hydrogen peroxide was injec-
ted. This indicated that a significant
fraction of hydrogen peroxide rapidly
decomposed to oxygen gas and
escaped into the unsaturated zone.
This Project Summary was
developed by EPA's Robert S. Kerr
Environmental Research Laboratory,
Ada, OK, to announce key findings of
the research project that is fully
documented in a separate report of
the same title (see Project Report
ordering information at back).
Introduction
The Superfund Amendments and
Reauthorization Act (SARA) of 1986
directed EPA to prefer remedial actions
involving treatment that would
permanently and significantly reduce the
volume and toxicity or mobility of hazard-
ous substances, pollutants, and contam-
inants over remedial actions not involving
such treatment. Therefore, the off-site
transport and disposal of hazardous
substances or contaminated materials
without treatment is the least favored
remedial action where practicable alterna-
tive treatment technologies are available.
Bioremediation is a relatively new
treatment technology that can be
implemented in-situ in which microorgan-
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isms metabolize organic contaminants
generally into harmless byproducts.
Aerobic bioremediation has been
reported to degrade a wide variety of
organic contaminants such as alkyl-
benzenes (benzene, toluene, xylene
(BTX)), polynuclear aromatic hydrocar-
bons, heterocyclic organic compounds,
and some of the simpler chlorinated
compounds. Recently, researchers have
found that transformation of trichloro-
ethylene by methane-oxidizing bacteria
under aerobic conditions is possible.
In aerobic respiration, free molecular
oxygen accepts electrons from an
electron donor, usually carbon, and is
reduced to a lower oxidation state. An
important aspect of these biochemical
redox reactions is their irreversibility;
therefore, dissolved oxygen is always
consumed and never produced as a
result of bacterial metabolism. Oxygen, if
not present in adequate concentration,
will limit the ability of aerobic micro-
organisms to degrade contaminants. The
rate of aerobic biotransformation, and
thus, contaminant persistence, has been
reported to be controlled by the transport
of oxygen into the contaminated ground
water.
Due to the dissolved oxygen sink in
biologically active contaminated aquifer
systems, oxygen supplementation is
required to maintain aerobic conditions.
Several methods, such as air sparging,
ozone injection, soil venting and liquid or
gaseous oxygen injection, have been
developed to increase and maintain the
concentration of dissolved oxygen in the
ground water.
Hydrogen peroxide injection into the
ground water is a popular method of
introducing oxygen to targeted contam-
inated low dissolved oxygen zones.
Hydrogen peroxide decomposition reac-
tions, ideally, yield one mole of water and
one mole of oxygen thereby introducing
pure oxygen into ground water. Hydrogen
peroxide is highly soluble and potentially
highly mobile, thus offering numerous
operational advantages in the field. How-
ever, relatively little information concern-
ing its utilization in a biologically active
contaminated aquifer system is currently
available.
The most important aspect of the
decomposition reaction is the liberation of
one mole of oxygen. The reaction
product, oxygen, is the basis for injecting
hydrogen peroxide due to the sub-
sequent replenishment of oxygen in the
ground water. The stoichiometry indi-
cates that 47.1% by weight of
decomposed hydrogen peroxide will be
pure oxygen.
The two main mechanisms for
hydrogen peroxide decomposition are
enzymatic and non-enzymatic reactions.
Enzymatic decomposition reactions are
catalyzed by hydroperoxidases (cata-
lases and peroxidases). Many scientific
observations have been reported
concerning catalysts; however, the
greatest attention has been centered on
the enzyme, catalase. Catalase, found in
most bacteria, is primarily responsible for
catalytically decomposing cell synthe-
sized hydrogen peroxide, thus preventing
the accumulation of hydrogen peroxide to
a toxic level. Catalase is Outstandingly
effective in this process, being active at
low hydrogen peroxide concentrations
and at a rate far exceeding that of most
other catalysts.
The most notable non-enzymatic
decomposition reactions are those in the
presence of iron salts and the generally
accepted mechanism is a series of
complex chemical reactions involving hy-
droxyl and perhydroxyl radical inter-
mediates and both ferric and ferrous iron.
Hydrogen peroxide decomposition was
not observed to be significantly affected
by pH in one laboratory study. However,
the presence of a 0.01 M solution of
Potassium Phosphate (monobasic) was
observed to significantly inhibit hydrogen
peroxide decomposition. Phosphate in-
hibition of hydrogen peroxide decom-
position is fortuitous since phosphate is
also an important microbial nutrient.
A laboratory study where hydrogen
peroxide provided the main source of
oxygen for hydrocarbon degrading bac-
teria, researchers reported that the
maximum concentration tolerated by a
mixed culture of gasoline degraders was
0.05% hydrogen peroxide. The tolerance
was increased to 0.2% by incrementally
raising the hydrogen peroxide concen-
tration. Tolerance was determined to
occur when the number of colony forming
units in the test column were essentially
the same for the control column.
Objectives
The objectives of the laboratory study
were to confirm that hydrogen peroxide
can be used to supply oxygen in the
bioremediation process, assess the
tolerance of the system to hydrogen
peroxide, and estimate the overall oxygen
demand based on stoichiometric degrad-
ation of hydrocarbon. A field scale in-situ
bioremediation pilot study in which
hydrogen peroxide and nutrients were
injected into contaminated aquifer ma-
terial provided the opportunity to confirm
laboratory observations in the field.
Methodology - Laboratory Stud
Contaminated aquifer material w;
collected from the heart of an aviatk
gasoline plume using a modified hoik
stem auger drilling tool. Approximate
476 g of wet, contaminated aquifer mate
ial was placed in triplicate columns. /
abiotic control column was not used
this experiment. The glass columns we
approximately 18 cm long (4 cm I.D
Soil columns were kept in a consta
temperature chamber at 12"C.
A mixture of feed water, nutrients, ar
hydrogen peroxide was pumped (peristc
tic pump) through the columns, "ft
columns were operated in a continuoi
upflow mode. Feed solutions were mixc
in an in-line mixing coil prior i
introduction to the columns. The influe
nutrient concentrations to the columr
was 400.0 mg/L Ammonium Chlorid
200.0 mg/L Potassium Phosphate (moni
basic), 200.0 mg/L Sodium Phosphat
and 100.0 mg/L Magnesium Sulfat
Hydrogen peroxide was introduced
15.0 mg/L. Effluent samples from tr
column were retrieved in-line using
syringe pump. This enabled the retriev
of an aqueous sample in a closed systei
without losing volatiles and withoi
aerating/deaerating the column effluer
An inverted centrifuge tube was installs
in-line to capture and quantify the g£
produced from the column.
Available oxygen (Available Oxyge
= [DO] + 0.471 [H202]) from both th
hydrogen peroxide and the dissolve
oxygen (DO) was measured using th
Winkler azide modification method (EP
Method No. 360.2). Hydrogen peroxid
analysis was determined using a perox>
titanic acid colorimetric procedure. Tti
columns were pretreated with a pho:
phate rich nutrient solution (128.0 mgi
Orthophosphate as P) prior to th
introduction of hydrogen peroxide. Th
pretreatment step was a precaution take
to prevent iron decomposition of hydrc
gen peroxide.
Results - Laboratory Study
Hydrogen peroxide was initiall
introduced at 15.0 mg/L. The oxyge
demand exerted on the influent wa
calculated as follows:
Oxygen demand
= (Influent [DO] + 0.471 [H202])
- Effluent [DO]
where the effluent DO concentration, a
determined by the Winkler metho<
detects both DO and oxygen fror
hydrogen peroxide. Approximately tw
weeks was required before significar
oxygen consumption was observed in a
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'hree columns. This response was
terpreted as characteristic of microbial
acclimation to a new chemical or physical
environment.
Hydrogen peroxide was increased
from 15.0 mg/L to 30.0 mg/L after the
oxygen demand exceeded approximately
80% of the available oxygen. This
increase corresponded to an additional
7.1 mg/L available DO. Hydrogen
peroxide was increased to 100.0 mg/L
after the oxygen demand exceeded
approximately 80% of the available
oxygen. Bubbles were observed in the
in-line gas traps indicating that a loss of
oxygen from the system was occurring.
During a period of fifteen days
following the hydrogen peroxide injection
of 100.0 mg/L, effluent DO remained
constant (DO avg. = 24.6 mg/L, n = 29,
st. dev. = 1.25 mg/L) in all three
columns. In-line gas traps were used to
capture and quantify the gas produced
from the columns. The average rate of
gas generation during this period from
columns B and C was 1.17 ml/hr. Gas
chromatograph analysis of the captured
gas indicated that the gas composition
was approximately 65%-70% oxygen and
30%-35% nitrogen.
A mass balance was performed on the
influent and effluent available oxygen in
he system. Mass balance results were
converted to moles/hr and are included in
Table 1. The oxygen mass balance
indicates that roughly 44.0% and 45.0%
of the influent oxygen was recovered in
the aqueous and gaseous phases
respectively for a total recovery of 89%.
The unrecovered oxygen was assumed
to be consumed both biotically and
abiotically. The cumulative total and
cumulative adjusted oxygen demand
curves were prepared for each column.
The cumulative adjusted oxygen demand
curve is the difference between the
cumulative total oxygen demand and the
oxygen lost from the system due to
degassing. The total and adjusted oxygen
demand curves demonstrated the
potential of hydrogen peroxide, at 100.0
mg/L to rapidly decompose resulting in
the production of pure oxygen. The
slopes of the cumulative adjusted oxygen
demand curves during the 100.0 mg/L
hydrogen peroxide injection period is less
than the slope at lower hydrogen
peroxide concentration periods during the
study. A decrease in the oxygen
consumption rate indicates that inhibition
of bacterial respiration during this period
may have occurred.
During the later stages of the study,
degassing was noted to occur at
hydrogen peroxide concentrations that
Table 1. Column Influent and Effluent
Flux of Available OxygenC**
in Both Aqueous and
Gaseous Phase
Influent
aqueous
Effluent
aqueous
gaseous
A
7.78E-S
3.41E-5
(43.8%)
3.5E-5M
(45.0%)
Columns
8
7.78E-5
3.4E-5
(43.7%)
3.71E-5
(47.7%)
C
7.78E-5
3.42E-5
(44.0%)
3.29E-5
(42.3%)
(1) Flux rate, moles oxygenlhr.
(2) Values in parentheses indicate percent
effluent of total influent flux.
(3) Average of columns B and C.
previously did not result in degassing. It
appears that this may have been due
primarily to enzymatic decomposition
associated with the additional biomass in
the system and the short retention time
of the bubbles in the column. Influent
hydrogen peroxide concentration during
the remainder of the experiment was
incrementally adjusted as the oxygen
demand changed with time.
The average cumulative total oxygen
demand from the columns was 1940 +
127 mg oxygen and the average
cumulative total oxygen demand,
adjusted for the oxygen degassing was
1360 + 67 mg oxygen. During the
various operating scenarios (i.e. varying
influent hydrogen peroxide concentration)
of this study, degassing accounted for
approximately 30% of the total oxygen
demand. The slope of the cumulative
adjusted oxygen demand curve
represents the overall rate of oxygen
consumption during the study period.
Gas chromatograph analysis of the
aquifer material and the column effluent
was performed to maintain a mass
balance of hydrocarbons in the system.
The amount of fuel carbon (FC) degraded
was estimated based on the mass of
aquifer material in each column, the initial
and final average FC concentrations, and
an estimate of the effluent FC. Based on
the average of all three columns, 36% of
the initial mass of fuel carbon leached
from the aquifer material, 10% remained
on the aquifer material, and 54%
degraded.
The empirical carbon and hydrogen
content of the aviation gasoline was
determined to be approximately 2.16
parts hydrogen per part carbon, or
roughly 85% carbon and 15% hydrogen.
The ideal stoichiometric biological
conversion of hydrocarbon to carbon
dioxide and water is approximately 3.48
parts oxygen per part hydrocarbon. The
ratio of the estimated oxygen consumed
to estimated aviation gasoline degraded
in this study was greater than the
stoichiometric conversion ratio (Table 2).
Measured conversion ratios greater than
the stoichiometric prediction was likely to
occur due to errors in the mass balance
analysis and the abiotic oxygen demand.
It was not possible to differentiate
between biotic and abiotic oxygen
demand in this study.
Table 2. Conversion Ratios (Oz(mg)/
Aviation Gasoline (mg))
Columns
ABC
Mass 02
consumed^)
1322.0 1307.0 1434.0
Mass 253.0
Aviation
gasoline®
degraded
(mg)
Conversion 5.23
Ratio mg
O2lmg Av.
gasoline
295.0 274.0
4.43 5.23
(1) Adjusted Cumulative Oxygen Demand
(2) Mass Aviation gasoline degraded =
Mass FC Degraded/(0.85)
Colorimetric hydrogen peroxide
analysis of the column effluent was
performed to determine the persistence
of hydrogen peroxide in the contaminated
aquifer material. Prior to terminating the
experiment, hydrogen peroxide was
injected at 50.0, 100.0, and 200.0 mg/L.
These concentrations were injected for 7,
10, and 13 hours, respectively, prior to
collecting effluent samples. Breakthrough
of hydrogen peroxide, for all three con-
centrations was less than 11% (Table 3).
Background - Field Study
Twenty years ago, aviation gasoline
(25,000 gal.) spilled into a shallow, sandy,
water table aquifer at the U.S. Coast
Guard Station in Traverse City, Michigan.
The spill site was cored extensively to
determine the distribution of contamina-
tion in the subsurface. The majority of the
contamination was found to be distributed
within a narrow interval between 15 and
17 feet below the land surface (Table 4)
corresponding to the seasonal low and
high water table at the site.
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Table 3. Hydrogen Peroxide Breakthrough
Columns
B
[H202]i(mg/L)
H202 Breakthrough
50.0
ND ND ND
B
B
100.0 200.0
9.6 10.4 2.5 16.5 17.0 9.3
9.6 10.4 2.5 8.3 8.5 4.7
[H2O2ji, /H2C>2/e influent and effluent hydrogen peroxide concentration, respectively
Detection limits: [H2O2]500= 5.0 mg/L, [HflJ 100.0,200.0 = 2-5
Table 4. Vertical Distribution of
Contamination 50 feet
Downgradient from the
Injection Wells
Depth Interval Fuel Hydrocarbons
(feet below surface) (mg/kg aquifer)
15.1-15.5
15.5-15.8
15.8-16.2
16.2-16.5
16.5-17.2
172-17.5
18.0-18.3
< 11
39
2370
8400
624
< 13
< 13
In 1988, the U.S. Coast Guard and the
U.S. EPA began the operation of a pilot
scale in-situ bioremediation project in the
area of the original spill. A series of five
deep wells were used to inject clean
water beneath the plume area in an effort
to raise the water table and subsequently
saturate the contaminated "smear zone".
Raising the water table was performed in
order to allow the delivery of soluble
nutrients to the targeted zones of
contamination. Five chemical feed wells
were used to inject nutrients and hydro-
gen peroxide in the shallow, contam-
inated layer. A series of downgradient
monitoring wells and subsurface
sampling points were installed to monitor
the performance of bioremediation.
Nutrient and oxygen injection began in
March 1988. A liquid oxygen source was
used to inject approximately 40 mg/L
dissolved oxygen. Approximately 3
months later (June 1988), hydrogen
peroxide was injected. Prior to hydrogen
peroxide injection, phosphate break-
through had occurred in the nested
monitoring wells. This was necessary to
complex the iron found in the aquifer
material with phosphates and therefore,
minimize the iron catalyzed hydrogen
peroxide decomposition reaction. Due to
problems associated with the chemical
feed system it was difficult to compare
the concentration of available oxygen in
the injected water with parameters
measured in the monitoring wells.
Both soil gas and ground water
analyses were used to investigate the
fate of hydrogen peroxide in the in-situ
bioremediation field scale pilot study.
Methodology - Field Study
Soil gas was sampled in the vicinity
of the injection area and analyzed for the
oxygen concentration. Soil gas samples
were obtained using a series of stainless
steel tubes (3/8 in. I.D.) that could be
coupled together and driven into the
subsurface to various depths. Soil gas
sampling mainly occurred in the 0-10 ft
range. Soil gas was pumped into a
sample vessel which contained an
oxygen detector using a hand held
positive displacement pump. The oxygen
detector is a GasTech Model LO2
OxyTechTor galvanic cell which mea-
sures the concentration of oxygen from
0-100% + 5% of the reading.
Results - Field Study
During the field investigation (8/89),
hydrogen peroxide was injected (11 gpm)
into ground water at 750 mg/L. The water
table in the injection area was
approximately 13.5-14.5 feet below
grade. This data was used to map the
horizontal distribution of oxygen as a
function of depth (3, 6, 9-10 ft.). Oxygen
was found in excess of 45% at the 9-10
ft. interval. The concentration of oxygen
in the unsaturated zone was clearly
greater than both atmospheric and back-
ground soil oxygen concentrations,
20.9% and 20.7% respectively. This
indicated that a significant amount of
oxygen was lost from the system and
was not available for bioremediation of
hydrocarbon in the saturated zone. This
data also indicated that the oxyge
concentration in the injection are
increased with depth. Unlike the injectio
area, the oxygen concentration in area
further downgradient decreased wit
depth.
The concentration of available oxyge
in ground water downgradient from th<
injection zone clearly indicated that oxy
gen was being delivered to the system.
was difficult to predict the rate at whicl
hydrogen peroxide decomposed or thi
fraction of injected oxygen that wa
liberated from the saturated zone. Thi
was largely due to the variability of th
influent hydrogen peroxide concentratio
as a function of time.
Conclusions - Laboratory Study
Hydrogen peroxide was shown t<
rapidly decompose and produce pur
gaseous oxygen. Due to precaution
taken to minimize nonenzymatic decom
position in this study, the data indicat
that hydrogen peroxide decomposition t
oxygen and water was mainly the resu
of enzymatic catalysts. Oxygen providei
by the hydrogen peroxide decompositio
reaction was consumed in the columns.
was not possible to distinguish betwee
abiotic and biotic oxygen demand in thi
study.
The injection of hydrogen peroxide c
100.0 mg/L had two observed notabl
effects. The rapid rate of decompositio
resulted in a high rate of oxygen ga
production. The rate of oxygen ga
production far exceeded the demanc
and although the solubility of dissolve
oxygen had not been exceeded, ga
bubbles appeared to have insufficier
time to diffuse from the gaseous phas
into the aqueous phase. Approximatel
45% of the available oxygen injected int
the columns was transferred into th
gaseous phase. Secondly, the rate c
oxygen consumption decreased indica
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:~ig that bacterial inhibition may have
ccurred.
Mass balances of both oxygen and
hydrocarbon was calculated to quantify
the mass of oxygen consumed and the
mass of hydrocarbon degraded. The ratio
of estimated oxygen consumed to
aviation gasoline degraded was found to
be greater than the stoichiometric
prediction.
Hydrogen peroxide, introduced into
the biologically active columns at 50.0,
100.0, and 200.0 mg/L, never exceeded
11% breakthrough although the columns
were only 18 cm in length.
Conclusions - Field Study
Injecting hydrogen peroxide into the
aquifer at the pilot study area resulted in
increasing the concentration of available
oxygen in downgradient wells, rapid
decomposition of hydrogen peroxide, and
the liberation of oxygen gas into the
unsaturated zone resulting in a concen-
tration much greater than background.
The rate of hydrogen peroxide decom-
position at the site was unknown but was
expected to be rapid due to the
concentration of oxygen gas measured in
the pilot study area.
Discussion
Results of the field investigation
support observations from the laboratory
study: hydrogen peroxide decomposed
resulting in the liberation of oxygen at a
rate faster than the oxygen could be
utilized biologically and solubilized into
aqueous phase. Subsequently, oxygen
gas was liberated from the ground water
into the unsaturated zone. The oxygen
gas which was liberated into the
unsaturated zone could be considered an
oxygen sink from the biodegradation
process in the saturated zone. This sink
introduces a considerable element of
uncertainty in estimating how much
oxygen is actually delivered to the
system and utilized in the biodegradation
process. Consequently, predicting the
amount of hydrocarbon degraded based
on the amount of hydrogen peroxide
delivered to the system is inaccurate.
Additionally, the data from this study
clearly dispels the concept that hydrogen
peroxide will only decompose as a
function of the biological oxygen demand.
Two areas addressed in the laboratory
study that were not investigated in the
field study are microbial inhibition due to
hydrogen peroxide and the stoichiometry
of the degradation of hydrocarbon based
on the amount of oxygen consumed. An
accurate mass balance of oxygen and
hydrocarbon is critical to make an
assessment of both processes. Neither
an oxygen nor a hydrocarbon mass
balance was accurately achieved at field
scale. Therefore these two areas could
not be investigated. An important note to
make however, is that the conversion
ratios found in the column study
represent minimum values due to the
oxygen and hydrocarbon mass balance
of a carefully controlled system. In a field
scale system, it is speculated that the
amount of oxygen required will be
significantly greater due to short
circuiting of the oxygen with respect to
the contaminant plume.
The decision to use hydrogen
peroxide as a supplemental source of
electron acceptor in bioremediation is an
issue of economics and safety. Prior to
selection of hydrogen peroxide as a
source of oxygen for bioremediation sys-
tems, alternative sources should be con-
sidered. These alternatives include liquid
oxygen and gaseous oxygen either
shipped in or produced on-site, i.e. oxy-
gen generation via molecular sieve.
Additionally, when estimating the costs
associated with using hydrogen peroxide,
consideration should be given to the
fraction of oxygen that is lost from the
system.
Recommendations for
Research
This study has focused on
investigating the feasibility of utilizing
hydrogen peroxide as a supplemental
source of oxygen for the enhanced
bioremediation of contaminated (aviation
gasoline) aquifer material. Clearly, injec-
tion of hydrogen peroxide into the ground
water will increase the concentration of
dissolved oxygen which can be used as
an electron acceptor in the bioremedia-
tion process. However, the rapid
decomposition of hydrogen peroxide as
observed in this study, and the
subsequent liberation of the oxygen gas
to the unsaturated zone will limit the
effectiveness of hydrogen peroxide to
supply oxygen to the saturated zone. The
following recommendations are sug-
gested to further evaluate the feasibility
of utilizing hydrogen peroxide as a
source of oxygen.
1 Research designed to differentiate
between biotic and abiotic mechanisms
of hydrogen peroxide decomposition will
offer the opportunity to more completely
understand the role of biological and
chemical variables in this reaction. The
application of this information could then
be used to develop methods to control or
minimize decomposition reactions.
Understanding these processes may also
help identify chemical and biological
subsurface conditions that are not
conducive to this method of oxygen
supplementation.
2. The results of the laboratory column
study found hydrogen peroxide at 100.0
mg/L to decrease the oxygen utilization
rate. A decline in the oxygen utilization
rate indicated that bacterial inhibition may
have occurred. While other research has
found the hydrogen peroxide microbial
toxicity threshold to be much higher,
these are usually based on bacterial
enumeration. The oxygen utilization rate
is a parameter which offers feedback on
the performance of the biodegradation
process. The concentration of hydrogen
peroxide identified in this research which
indicated bacterial inhibition had occurred
has paramount importance since it is
process oriented and is relatively low.
Additional research is necessary both to
verify this observation and to more
closely examine the toxicity effect from a
process perspective.
3. The feasibility of using hydrogen
peroxide as a supplemental source of
oxygen at a bioremediation site must
consider also the economics and safety
of this method compared to other
candidate methods. Included in this
evaluation are: the cost of the hydrogen
peroxide; operation and maintenance
costs of the equipment to store, mix, and
deliver the hydrogen peroxide; the
fraction of oxygen actually delivered to
the saturated zone; toxicity; and safety. A
comprehensive feasibility evaluation is
necessary to identify the technical and
economic benefits of using various
techniques of oxygen supplementation.
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Scott G. Huling (also the EPA Project Officer, see below) and Bert E. Bledsoe
are with the U.S. Environmental Protection Agency at the Robert S. Kerr
Environmental Research Laboratory, Ada, OK 74820. Mark V. White is with
the NSI Technology Services, Corp., Ada, OK 74820.
The complete report, entitled "Enhanced Bioremediation Utilizing Hydrogen
Peroxide as a Supplemental Source of Oxygen: A Laboratory and Field
Study," (Order No. PB 90-183 435/AS; Cost: $17.00, subject to change)
will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK 74820
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-90/006
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