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Remediation of hydrocarbon contaminated soils in the
Canadian Arctic by landfarming
Krysta Paudyn a, Allison Rutterb ,, R. Kerry Rowe a, John S. Poland b
aGeoEngineering Centre at Queen's-RMC, Department of Civil Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6
b School of Environmental Studies, Queen's University, Kingston, Ontario, Canada K7L 3N6
Received 8 December 2006; accepted 24 July 2007
Abstract
One of the preferred methods for the remediation of fuel contaminated soil today is landfarming. This is particularly true for
remote sites because the method requires minimal equipment and is therefore by far the lowest cost option. The term landfarming
generally refers to the process whereby hydrocarbon contaminated soils are spread out in a layer about half a meter thick, nutrients
are added, and periodically the soils may be mixed. During landfarming, hydrocarbons can be lost through volatilization or
bioremediation and thus landfarming refers to the combination of the two processes.
In the challenging Arctic climate, the performance of landfarming studies has been variable and the relative contribution of the
two processes has not been studied. This paper describes the successful remediation of diesel-contaminated soils at the former
military base at Resolution Island, Nunavut. The site is 130 km from the nearest community and this isolation together with very
inclement weather and average summer temperatures of 3 C presents significant challenges for remediation. Trial landfarm plotswere established in 2003 to compare four sets of conditions; daily aeration, aeration every 4 days, addition of fertilizer with aeration
every 4 days and a control plot. The field trial has clearly demonstrated enhanced bioremediation when fertilizer was added and
also significant hydrocarbon losses due to aeration by rototilling. The rate of bioremediation was similar to the rate of volatilization
in the field trial. In addition to the landfarms established on site, extensive complementary laboratory experiments have been
carried out. Bioremediation was demonstrated at 5 C in the laboratory reactors and isoprenoid markers indicated increased
bioremediation with increased temperatures. In the reactor experiments, rate constants for volatilization and bioremediation
increased with temperature.
2007 Elsevier B.V. All rights reserved.
Keywords:Landfarming; Hydrocarbon; Remediation; Arctic; Bioremediation; Volatilization
1. Introduction
The term landfarming refers to the process where
hydrocarbon contaminated soils are spread out in a layer
of 0.31.0 m thick, nutrients are added and the soils are
mixed periodically. During the process of landfarming,
the total petroleum hydrocarbons, (TPH), may be lost
through volatilization or biodegradation. Landfarming
refers to the combination of the two processes. Treatment
regimes for landfarms vary with climate, location, tem-
perature and soil type. Enhanced bioremediation of con-
taminated soil typically involves the addition of nutrients
and water, and periodic tilling to mix and aerate the soil
(McCarthy et al., 2004). Additional amendments (e.g.,
Available online at www.sciencedirect.com
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Corresponding author. Tel.: +1 613 533 2642; fax: +1 613 533
2897.
E-mail address:ruttera@biology.queensu.ca(A. Rutter).
0165-232X/$ - see front matter 2007 Elsevier B.V. All rights reserved.doi:10.1016/j.coldregions.2007.07.006
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bulking agents to increase aeration (Straube et al., 2003),
co-substrates to stimulate microbial metabolism
(Mphekgo and Cloete, 2004) or bacterial inoculations
(Straube et al., 2003) are sometimes added to speed the
remediation process. Landfarming has proven consis-
tently successful in warmer southern climates, (Mc-Carthy et al., 2004). For instance, in the 12-month
operational period of an Australian landfarm TPH levels
were remediated from 4644 ppm to less than 100 ppm
(Line et al., 1996).
In colder Antarctic and Arctic climates, trials involv-
ing landfarming or bioremediation have been conducted
with mixed results (Delille, 2000; Seklemova et al.,
2001; Aisablie et al., 2004; McCarthy et al., 2004).
Research has shown the presence of organisms adapted
to cold conditions at sites where hydrocarbon contam-
ination is present in these cold climate soils (Mohn andStewart, 2000). Hydrocarbon degrading extremophiles
are thus ideal candidates for the biological treatment of
polluted extreme habitats such as the Canadian Arctic,
(Rike et al., 2003; Mohn and Stewart, 2000). A wide
variety of microorganisms have been detected in the
active layer in Arctic soils in northern Canada and
Alaska (Deming, 2002). These cold habitats possess
sufficient indigenous microorganisms forin situ biore-
mediation, (Whyte et al., 1999; Ferguson et al., 2003).
They adapt rapidly to hydrocarbon contamination in the
soil, as demonstrated by significantly increased numbers
of oil degraders shortly after a pollution event (Atlas,1995). An increased number of the hydrocarbon degrad-
ing bacteria in response to oil spills has been reported by
bothWhyte et al. (1999) and Rike et al. (2001)illustrat-
ing that growth and proliferation of hydrocarbon
degrading bacteria have taken place under site-specific
conditions. Over the past several years, a number of
studies in both Arctic and Antarctic regions have shown
that microorganisms naturally occurring in harsh envi-
ronments are capable of degrading petroleum hydro-
carbons (McCarthy et al., 2004; Mphekgo and Cloete,
2004; Ferguson et al., 2003; Kerry, 1993).Landfarming has been used in cooler locations such
as alpine environments (Margesin and Schinner, 2001)
and Alaska (Reynolds et al., 1998) where summer tem-
peratures are much higher than those of the central and
eastern Canadian Arctic. Rates of biodegradation and
volatilization have been shown to be slower at low
temperatures (Snape et al., 2005), however the relative
rates and therefore their contributions to landfarming in
Arctic climates are still relatively unknown. The per-
centage of remediation attributable to aeration in various
field studies varies (Reimer et al., 2003; Chatham, 2003;
Ausma et al., 2002). In order to study the bioremediation
of hydrocarbons ratios of n-alkanes to pristine and
phytane can be used for good effect (Atlas, 1995;
Ferguson et al., 2003). There are many landfarms estab-
lished in cold climates, however, there is a paucity of
well documented field trials. This work describes a field
study specifically designed to assess the relative con-tributions of bioremediation and volatilization using
aerated and fertilized regimes. The trial landfarm ex-
periment was established at Resolution Island in the
summer of 2003 in order to determine the viability of the
landfarming technology for remediation of TPH con-
taminated soils at the site. Resolution Island is located at
the southeastern tip of Baffin Island approximately
310 km southeast of Iqaluit, Nunavut. The site is
accessible for fieldwork for approximately 3 months a
year and during that time often suffers from inclement
weather; including heavy fog and rainstorms. The aver-age temperature during the summer months is 3 C.
Resolution Island was the site of one of the military
bases that formed the Polevault Line. The site has been
the site of a major cleanup operation as it was highly
contaminated with polychlorinated biphenyls, (PCBs),
metals and petroleum hydrocarbons (Poland et al.,
2001).
Ex situstudies of landfarming have focused on nut-
rients (Ferguson et al., 2003; Braddock et al., 1997),
bioaugmentation (Mohn and Stewart, 2000; Van Veen
et al., 1997), cold adapted organisms (Kunihiro et al.,
2005; Mikan et al., 2002), oxygen depletion (Zytneret al., 2001) and water content (Ferguson et al., 2003).
Many studies attempt to assess the viability of biore-
mediation using radiolabelled linear hydrocarbons
(Mohn and Stewart, 2000; Braddock et al., 1997) but
the extrapolation to field studies is often difficult
(Zytner et al., 2001). In this study, laboratory reactors
were designed to model the trial landfarm established at
Resolution Island and to investigate the effect of
temperature on volatilization and bioremediation.
There are many hydrocarbon contaminated sites which
require remediation in the Arctic and there is currentlyno criterion available to determine if landfarming will be
viable at a given site. This study outlines the
experimental design and initial laboratory experiments
that are intended to establish these criteria and field
protocols.
2. Methodology
2.1. Trial landfarm
Three truckloads (30 m3) of TPH contaminated soil
were excavated from two diesel-contaminated areas on
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site. The soil was displaced to an area that had been
previously leveled to a slope less than 5%. Heavy
equipment was used to homogenize the soil cache and
evenly distribute the material to each of the four plots.
Each plot measured 5 m by 5 m with a depth of
0.3 m. Maintenance and operation of the triallandfarm included subjecting each plot to a different
regime (Fig. 1). One plot was established as the
control plot and had no action other than sampling.
Aeration was achieved by rototilling. Two plots were
rototilled only; one every day and the other every
fourth day. The final plot was rototilled every 4 days
and, in addition, fertilizer was added to this plot. Thus
the four plots were maintained as follows: control
plot; daily aeration; aeration every 4 days; fertilizer
added with aeration every 4 days. As a result of
operational experiences during the first season, in thesecond season, the regime of aeration frequency
considered only fair days; fair days were defined as
days when it was not raining, snowing or excessively
foggy.
The fertilizer was added on day 16. Nitrogen and
phosphorus were added to the landfarm plots in the form
of granular agricultural fertilizers. Urea, containing 46%
nitrogen was the primary source for nitrogen while phos-
phorus was added as diammonium phosphate, (DAP),
which contained 20.1% phosphorus and 18.0% nitrogen
by weight. Nutrient additions were based on applying a
C:N:P ratio of 100:7.5:0.5. No additional fertilizer wasadded to any of the trial landfarm plots after the initial
application on day 16.
The soil at Resolution Island can be characterized as
follows. It is largely composed of sand and gravel par-
ticles with only 10% of particles finer than 75 M. Thesoil has no plasticity, the soil pH is 5.8 and the organic
content is 1.1%.
2.2. Laboratory reactor design
The reactor design is presented inFig. 2. The body ofthe individual reactors was constructed with polyvinyl
chloride (PVC) sewer pipe cut into 0.36 m lengths. The
length of the tube was chosen to accommodate approxi-
mately 1.2 kg of soil such that the soil level was below
the mid-point air inlet of the reactor. The landfarm
aeration process was simulated by inverting the reactor
Fig. 1. The trial landfarm at Resolution Island Nunavut. Maintenance regime as indicated in photograph.
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tube. At the reactor base a cap was glued in place while
at the top of the reactor tube a removable cap was press
fitted and sealed with electrical tape. Air was passed
through the reactors at mid-height through a 0.016-m
brass fitting which was screwed into the tapped sewer
pipe and sealed with Teflon tape. For the air outtake, a0.016-m brass fitting, was 0.08 m higher than the inlet
and at an angle of 120 to it. A ball valve was glued into
position beside the outtake tube of each reactor to allow
water to be added to the system. This arrangement
allowed the inversion of the tube without soil entering
the air passages. A 2.5-m long, 0.102-m diameter high
density polyethylene (HDPE) tube was used as an air
pressure containment vessel between the air source and
the individual reactors. This tube was affixed to the
laboratory compressed air line. Holes were drilled and
tapped into the tubing to support 24 pressure regulatorvalves that were then each attached to a reactor allowing
regulation of air flow through each reactor. The air
entering the manifold from the line was controlled to the
temperature of the room by passing source air through
10 m of coiled copper pressure tubing. In addition,
source air was passed through a 0.15-m long charcoal
filter (0.03 m diameter), which ensured that hydrocar-
bon contamination from the source line was eliminated.
Volatilized hydrocarbon was captured at the air outlet of
each reactor with a granulated activated coconut char-
coal (GAC) trap. Each trap was 0.20 m long with an
internal diameter of 0.015 m and filled with approxi-
mately 20 g of 1240 mesh granulated activated coco-
nut charcoal.
2.3. Reactor system
The individual reactors were designed to reflect thephysical conditions that contaminated soil was subject
to in a field landfarm. Depth, tillage (inversion of the
individual reactors), temperature, windspeed, moisture
content were each considered in the reactor design and
protocol. By monitoring both volatilized and residual
hydrocarbon, it was possible to attribute loss of TPH to
either bioremediation or aeration using a mass balance
approach.
Each reactor was filled with 1.2 kg of diesel-con-
taminated soil from Resolution Island. Air was passed
through each of the closed vessels and volatilized TPHfrom the soil was collected on charcoal tubes at the
reactor air outlet. The charcoal filters were replaced and
analyzed for TPH periodically and the soil in each
reactor was also analyzed periodically. Moisture content
was carefully monitored and maintained in the range
of 1015% by the periodic addition of water. Flow
rate through each reactor was monitored daily and kept at
1 L/min. Reactor systems, each comprising 24 reactors,
were set up in three temperature controlled rooms
maintained at 5 C, 8 C and 18 C.
Two sets of reactor experiments are reported on here.
In the first experimental set, at each temperature, reactors
Fig. 2. Design of the laboratory reactors used for the ex situwork.
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significance difference between plots on day one of the
trial but all other samplings showed a significant differ-
ence between the plots (pb0.05 on day 16,pb0.005 all
other sampling days). At the end of the first season (day
31) all three treatment plots were significantly different
(t-test, p b0.05) than the control plot and the TPH con-
centration in the fertilizer added, aerated every 4 days
treatment plot was significantly lower than the other two
treatment plots (t-test,pb0.05). At the end of the second
season the same trend continued and it was clear that the
rate of remediation was as follows: control plotbaeratedevery 4 daysbaerated dailyb fertilized and aerated every
4 days (t-test, pb0.05). By the end of the third season
there were no significant differences between the three
treatment plots but all three treatment plots were still
significantly different than the control plot (t-test, pb
0.05). Initial TPH levels for all plots were 2800 ppm and
final concentration in the fertilizer added plot was below
200 ppm. Significant variations were noted for TPH
concentrations in each plot for a given season and the
average relative standard deviations for the data points in
Fig. 3 was 28%. Weathered TPH contaminated soil is
difficult to homogenize which contributes to the problem
of obtaining consistent data under both field and labo-
ratory conditions. Lower results were obtained when
sampling occurred on wet days where the landfarm was
Fig. 4. C17/Pr Ratios for the trial landfarm over the three seasons.
Fertilizer was added on day 16. Five samples were taken from eachplot and averaged. Error bars are one standard deviation.
Fig. 3. Concentrations of TPH in soil for the trial landfarm over the three seasons. Five samples were taken from each plot and averaged. Error bars are
one standard deviation.
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waterlogged and the sample water content was 15%
or greater. This is consistent with reports by Fine et al.
(1997)that sorption of hydrocarbons to soils is reduced
as water content increases. Despite large variations
the results show a clear trend. The fertilized plot shows
a striking decrease in TPH levels by over 90%. Thedaily aerated plot and the aerated every 4 days shows
losses in excess of 80%. These data are consistent
with successful landfarm results reported byChatham
(2003) and Reynolds et al. (1998). The control plot
TPH levels were reduced (t-test,pb0.05) but remained
above 1000 ppm after 3 seasons. Rate constants for the
loss of TPH based on first order reactions are discussed
below.
Pristane (Pr), (C19H40) and phytane (Ph), (C20H42)
are two isoprenoid alkanes present in diesel fuel. Also
present in diesel fuel are straight chain isomers C17H36(C17) and C18H38 (C18) of similar boiling points to
pristane and phytane respectively. The branched nature
of the pristine and phytane compounds makes them
relatively resistant to biodegradation when compared to
the linear counterparts (Atlas, 1995). The nature of the
compounds yields similar rates of volatilization, and
therefore major volatilization will result in no net change
in the isomeric ratios. A measurable change in the iso-
meric ratios is an indication that bioremediation is oc-
curring in the affected soil (Snape et al., 2005; Kerry,
1993).
The C17/Pr ratios were calculated using the chroma-
tograms of extracted soil samples from the plots to
determine if significant bioremediation was occurring.
For the 3 plots with no fertilizer added, (Fig. 4)theC17/Prratios did not change significantly indicating that no
measurable bioremediation was occurring. Moreover,
for the plot that had fertilizer applied, the C17/Pr ratios
were dramatically reduced indicating significant biore-
mediation had occurred. Similar results were found for
the C18/Ph ratios although there were small but signi-
ficant decreases (t-test, pb0.05). for the non-fertilized
plots. Overall the data therefore demonstrates that biore-
mediation is viable at the site but shows that aeration can
also achieve very significant reductions in TPH. The
addition of fertilizer is low maintenance and economi-cally enticing when comparing this option to daily
tilling. The fertilized plot was rototilled every 4 days but
it is not clear how necessary this soil aeration step was in
assisting the bioremediation; oxygen is necessary for
bioremediation of TPH to occur. Zytner et al. (2001)
found evidence of oxygen depletion after 30 days.
Laboratory experiments described below were set up to
address this issue and facilitate the development of an
optimal landfarm operation protocol in cold climates.
Fig. 5. Concentrations of TPH in soil in the laboratory reactors at 5 and 18 for control, aerated daily, aerated every 4 days and aerated every 4 days andfertilized. Six reactors were used for each regime at each temperature.
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3.2. Laboratory reactors
The reactor sets indicated that by aerating every
4 days and fertilizing, the TPH contaminated soil could
be remediated at all 3 temperatures. The TPH levels
generally decreased with time, with the control samples,which were not rotated, showing the least decrease of
the four regimes. In the first set, after approximately
5 months, 78% of the TPH had been remediated from
the soil at 18 C in the fertilized reactors. The TPH in the
soil at 8 C and 5 C was remediated 36% and 51%
respectively. For both reactor sets, the decrease in TPH
was significantly better (pb0.05) at 18 C as compared
to 5 C, indicating, as would be expected, improved
remediation with increased temperature. The remedia-
tion at these lower temperatures is important because it
demonstrates that this regime is applicable to sites withcolder temperatures than Resolution Island. Cold tempe-
rature hydrocarbon degraders have been isolated (Rike
et al., 2001) and remediation at 2 and 5 C has been
demonstrated by Zytner et al. (2001). The fertilized
reactors exhibited the largest decrease in TPH con-
centration over the course of the experiment for all
temperatures.
Fig. 5illustrates the differences between the 5 C and
18 C reactor sets from the first set of reactors. The
fertilized aerated every 4 days reactor systems were
significantly different than the control reactor systems
(t-test, pb0.05) by day 42 at 5 C and by day 54 at18 C. The average relative standard deviation of the
data points in Fig. 5 is 19%. At 18 C, the results are
similar to the landfarm with the fertilized and rotated
every 4 days reactor systems being significantly dif-
ferent (t-test,pb0.05) than the non-fertilized and rotated
every 4 days reactor on sampling days 42, 52, 138 and
169. At 5 C the difference is less clear with aerationalone as effective as fertilizer added and aerated every
4 days for most of the trial; there is no significantly
difference (pb0.05) until days 127 and 169 at 5 C. The
C17/Pr ratios presented inFig. 6indicate that there was a
C17/Pr isoprenoid ratio decrease in only the reactors to
which nutrients were added. The decrease in the ratio
increases with temperature (Fig. 6). The C17/Pr ratios
indicate that bioremediation is delayed and slower at
5 C. Results of the second reactor set showed little
difference between the 4- and 12-day rotation schedule.
However in the field, daily aeration did result in an
increased rate of volatilization. For the fertilized set offour reactors that were not rotated but had fertilizer
added, bioremediation was evident. This result holds
promise for in situbioremediation.
Analysis of the charcoal tubes enabled the amount of
TPH lost through aeration alone to be quantified. Data
for the first set of experiments is presented inTables 1
and 2.Table 1indicates the total TPH volatilized from
the reactors while inTable 2the mass of TPH volatilized
as a function of time at 18 C is given. As one would
Table 1
Total mass of TPH collected on charcoal traps (mg) over duration of
the experiment (169 days)
Reactor type Code Total mass of TPH collected on
charcoal traps (mg)
18 C 8 C 5 CControl CP 1200 460 390
Everyday A-1D 2580 1420 1510
Every 4 days A-4D 2270 1180 1210
Fertilizer F-4D 1960 1100 1160
Experimental code: CP = control plot; A = aeration alone while F =
fertilizer added; -xD = rotation every x days.
Fig. 6. C17/Pr ratios in the laboratory reactors at three temperature from
the first reactor set. Six reactors were used for each regime at eachtemperature.
Table 2Mass of TPH collected during experiment per day (mg/day) at 18 C
Reactor code Mass of TPH collected during experiment per day
(mg/day)
Days from start of experiment
130
days
3151
days
5277
days
78126
days
127169
days
CP 9 6 4 10 5
A-1D 24 17 16 16 8
A-4D 22 11 11 14 9
F-4D 21 12 11 10 5
Experimental code: CP = control plot; A = aeration alone while F =fertilizer added; -xD = rotation every x days.
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expect, the amount of TPH volatilized increased with
temperature (Ausma et al., 2002). In addition, the mass
volatilized increased with the frequency of rotating the
reactors. Thus, for the six control samples averaged in
the first line ofTable 1, the amount of TPH aerated for
the three temperatures of 18 C, 8 C, and 5 C was
1200, 460 and 390 mg respectively. For the 18 C
reactor sets, the amount of TPH volatilized was 1200 mg
for the control samples, 2270 mg and 1960 mg for thetwo sets rotated every 4 days and 2580 mg for the set
rotated every day (Table 1). These results indicate that
volatilization of TPH increases with a regime that in-
cludes aeration. Similar trends are seen at all tempera-
tures in the second set of reactors. The mass of TPH
volatilized decreased with time (Table 2). This is to be
expected as the mass of TPH remaining in the soil
decreases with time as it is removed from the system.
The charcoal tubes enabled the calculation of a mass
balance for the reactor systems. In each experiment, no
net loss or gain of TPH should be evident unlessbioremediation is occurring.Fig. 7indicates the net loss
of TPH in the second set of reactors. Both sets show that
TPH was removed from the soil in the fertilized reactors
by both volatilization and bioremediation while all other
reactors only exhibit loss through volatilization. These
experiments indicate that both mechanisms were
occurring in the fertilized regimes even at temperatures
as low as 5 C. These laboratory results support the
results obtained in the field study at Resolution Island. It
should be pointed out that there is large imprecision for
TPH concentrations in soil analysis (approximately 30%
variation) due to the heterogeneity of the soil. This is
further extenuated when calculating for a mass balance
and is indicated in a large coefficient of variation for
each system (Fig. 7).
3.3. Rate constants
In previous studies, the TPH degradation has been
modeled using first order rate constants in both
unfertilized and fertilized soil systems (Demque et al.,1997; Zytner et al., 2001). For this system, the rate of
loss of TPH is proportional to its concentration.
d TPH
dt kTPH
where [TPH] is the concentration of TPH and t is the
time. Integration of above equation yields
ln TPH t kt ln TPH 0 and TPH t TPH 0ekt
where [TPH]t is the TPH concentration at time t and
[TPH]0is the initial concentration of TPH in the system.
The first order rate constant,k, is the slope of the line for
a plot of the natural log of [TPH] with respect to time.
The fit of the line to the average TPH data can be
described by ther2 value, where a value of 1.0 indicates
a perfect fit. The fit of the line gives an indication of the
fraction of the variance in the slope of the line. A
fraction of variance (r2) of less than 0.90 may be due to
the large error, associated with the average TPH in soil
values (20%) used to calculate the first order rate
constants. The nature of the Arctic climate, especially
Fig. 7. Net loss of TPH in the second reactor set, {TPH initial (soil)TPH final (soil)1169 TPH (charcoal)}mg=TPHnet. Error bars represent thecoefficient of variation for each regime.
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the extreme temperatures in the winter season, has led to
the assumption that biodegradation exhibits a hiatus
during the winter season when the soil is frozen (Rike
et al., 2001). However other models (Huesemann and
Truex, 1996) and some studies (Zimov et al., 1996;Oechel et al., 1997; Jones et al., 1999) have shown that
bioremediation sometimes occurs in the winter months
but with significantly reduced microbial activity and in
no lower than 5 C temperatures (Cline and Schimel,
1995).
Rate constants have been calculated for the experi-
mental landfarm and the laboratory reactors (Tables 3
and 4). For the landfarm, it was assumed that reme-
diation did not occur in the winter months (Table 3).
This is not unreasonable since soil temperatures as low
as 40 C can be expected from mid-September to late
June (Schimela et al., 2004). Therefore, the time scalewas adjusted to exclude the winter months, when the
landfarm was unmanaged, from the rate calculation. For
the summer field season, the average soil temperature
was 9.3 C. Rate constants from this experiment agree
with those from previous studies (Zytner et al., 2001).
Data for the second laboratory set are presented in
Table 4; similar results were obtained for reactor set 1.The rate constants have been calculated in two ways
from the rate of loss of hydrocarbon to the charcoal
traps, k(GAC) (volatilization only) or from the TPH
concentration data, k(TPH), (volatilization and biore-
mediation). Rate constants for bioremediation, k(BIO),
were obtained by subtraction of the TPH derived rate
constant aeration rate from the nutrient added equivalent
treatment.
An examination of the rate constants with respect to
the mechanism of aeration indicates that the data can
generally be described by first order kinetics. In thereactor experiments, rate constants increase with tempe-
rature and with the frequency of aeration. The k(GAC)
data yields a high fraction of variance with frequent
aeration (r2N0.94 in 90% of cases). Without rototilling
the rate of volatilization is likely dependent on rate of
diffusion of TPH in soil. The field control plot yields a
rate constant of 0.007 day1. This predominantly repre-
sents loss due to aeration and any losses due to erosion.
For the daily aeration field plot the calculated rate con-
stant is 0.017 day1 while the 4-day rototilling regime
yields a value of 0.015 day1. Thus, not unexpectedly,
the daily aeration regime resulted in a greater loss ofTPH due to volatilization. The C17/Pr ratios for both
Table 4
First order rate constants for TPH remediation for reactor set 2
Temperature Code Rotation frequency k(GAC) r2 k(TPH) r2 k(BIO)
C day day1 day1 day1
5 CP 0 0.001 0.89 0.002 0.58
5 F-0D 0 0.001 0.87 0.006 0.65 0.004
5 A-4D 4 0.002 0.98 0.002 0.95
5 F-4D 4 0.002 0.92 0.009 0.67 0.007
5 A-12D 12 0.001 0.94 0.003 0.50 5 F-12D 12 0.001 0.87 0.009 0.68 0.009
8 CP 0 0.001 0.90 0.002 0.40
8 F-0D 0 0.007 0.81 0.007 0.85 0.005
8 A-4D 4 0.002 0.97 0.005 0.95
8 F-4D 4 0.002 0.89 0.012 0.83 0.008
8 A-12D 12 0.001 0.81 0.005 0.78
8 F-12D 12 0.001 0.84 0.012 0.94 0.007
18 CP 0 0.002 0.98 0.003 0.83
18 F-0D 0 0.001 0.88 0.012 0.70 0.009
18 A-4D 4 0.003 0.97 0.006 0.92
18 F-4D 4 0.003 0.96 0.016 0.95 0.010
18 A-12D 12 0.003 0.94 0.005 0.79
18 F-12D 12 0.002 0.85 0.016 0.67 0.011
Experimental code: CP = control plot; A = aeration alone while F = fertilizer added; -xD = turning of laboratory reactors every x days.
Table 3
Rate constants calculated for the on site landfarm at Resolution Island
Temperature Code Rototilling frequency k(TPH) r2 k(BIO)
C day day1 day1
9 CP 0 0.007 0.58
9 A-1D 1 0.017 0.80
9 A-4D 4 0.015 0.94
9 F-4D 4 0.026 0.83 0.011
Experimental code: CP = control plot; A = aeration alone while F =
fertilizer added; -xD = rototilling every x days.
111K. Paudyn et al. / Cold Regions Science and Technology 53 (2008) 102114
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in soil in cold climates by landfarming with various
summer soil temperature conditions as well as contain-
ment strategies.
Acknowledgements
Department of Indian Affairs and Northern De-
velopment (DIAND) and the Northern Scientific Train-
ing Program (NSTP), (Indian and Northern Affairs
Canada).
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