\ I/
United States
Environmental Protection
Agency
Robert S. Kerr Environmental
Research Laboratory
Ada OK 74820
Research and Development
EPA/600/S6-86/003 Feb. 1987
Project Summary
Waste-Soil Treatability Studies
for Four Complex Industrial
Wastes: Methodologies and
Results, Volumes 1 and 2
R. C. Sims, J. L. Sims, D. L. Sorensen, W. J. Doucette, and L. L. Hastings
The full two-volume report presents In-
formation pertaining to quantitative evalu-
ation of the soil treatment potential re-
sulting from waste-soil interaction studies
for four specific wastes listed under Sec-
tion 3001 of the Resource Conservation
and Recovery Act (RCRA). Volume 1 con-
tains information from literature assess-
ment, waste-soil characterization, and
treatability screening studies for each
selected waste. Volume 2 contains results
from bench-scale waste-soil interaction
studies; degradation, transformation, and
immobilization data are presented for four
specific wastes: API separator sludge, slop
oil emulsion solids, pentachlorophenol
wood preserving waste, and creosote
wood preserving waste. The scope of the
study involved assessment of the poten-
tial for treatment of these hazardous
wastes using soil as the treatment
medium.
The experimental approach used in this
study was designed to characterize de-
gradation, transformation, and immobiliza-
tion potentials for hazardous constituents
contained in each candidate waste. For
each waste and soil type, treatment was
evaluated as a function of waste loading
rate, soil moisture, and time. Combinations
of selected chemical analyses and bio-
assays were used as endpoints to char-
acterize treatment.
Methodologies were developed for the
measurement of specific soil treatment
parameters including "volatilization-
corrected" degradation rates and for
measurement of partition coefficients
among waste, water, and air phases of a
waste-soil matrix. Partitioning between the
water soluble extract of the waste-water-
air mixture and soil was evaluated by con-
ducting soil isotherm studies using the
water soluble extract. These parameters
provide input to the proposed U.S. En-
vironmental Protection Agency (EPA) Reg-
ulatory and Investigative Treatment Zone
(RITZ) model developed to assess treat-
ment potential for potentially hazardous
organic constituents in soil.
This Project Summary was developed
by EPA's Robert S. Kerr Environmental
Research Laboratory (RSKERL), Ada, OK,
to announce key findings of the research
project that is fully documented in a
separate two-volume report of the same
title (see Project Report ordering informa-
tion at back).
Introduction
Land treatment (LT) is defined in RCRA
as the hazardous waste management
technology pertaining to application/incor-
poration of waste into upper layers of the
soil for the purpose of degrading, trans-
forming, and/or immobilizing hazardous
constituents contained in the applied
waste (40 CFR Part 264). Soil systems for
treatment of a variety of industrial wastes
have been utilized for many years; al-
though, application of hazardous industrial
waste to soil utilizing a controlled engine-
ering design and management approach
has not been widely practiced. This is due,
in part, to the lack of a comprehensive
technical information base concerning the
behavior of hazardous constituents in the
soil treatment zone as specifically related
-------
to current regulatory requirements (40
CFR Part 264) concerning treatability, i.e.,
degradation, transformation, and immobil-
ization of such constituents. Soil treat-
ment systems that are designed and
managed based on knowledge of waste-
soil interactions may represent a signifi-
cant technology for simultaneous treat-
ment and ultimate disposal of selected
hazardous wastes in an environmentally
acceptable manner. This treatment con-
cept also may be useful during remedial
activities at certain contaminated soil
sites.
In this research project, representative
hazardous wastes from two industrial
categories, wood preserving and petro-
leum refining, were evaluated as to the
potential for treatment in soil systems. A
literature assessment for each waste cat-
egory was conducted as an aid in the pre-
diction of soil treatment potential. The
literature review also was used as a guide
for design of an experimental approach for
obtaining specific information pertaining
to degradation, transformation, and im-
mobilization of hazardous waste constit-
uents in soil.
Standards were promulgated in 40 CFR
Part 264.272 for demonstrating treatment
of hazardous wastes in soil. These stand-
ards require demonstration of degradation,
transformation, and/or immobilization of a
candidate waste in the treatment zone
soil. For the purposes of this research,
demonstration of degradation of waste
constituents was based on the loss of
parent hazardous organic compounds
within the waste-soil matrix as opposed
to "complete" degradation, which is the
term used to describe the process where-
by waste constituents are mineralized
completely to inorganic end products, i.e.,
carbon dioxide, water, and inorganic
species of nitrogen, phosphorus, and
sulfur. Rates of degradation were estab-
lished by measuring the loss of parent
compounds from the waste-soil matrix
with time. Transformation refers to partial
alteration of hazardous compounds in the
soil, thereby converting a problem waste
or substances into innocuous or environ-
mentally safe forms. In this context, trans-
formation refers to formation of inter-
mediate products during waste-soil inter-
actions (i.e., physical, chemical, and/or
biological mechanisms); some intermedi-
ate products may become refractory com-
pounds in the soil matrix. Immobilization
refers to the extent of retardation of the
downward transport (leaching potential)
and upward transport (volatilization poten-
tial) of waste constituents. The transport
potential for waste constituents from the
waste to water, air, and soil phases is af-
fected by the relative affinity of the waste
constituents for each phase, and in this
project was characterized in column and
batch reactors. Therefore, an acceptable
demonstration of soil treatment involves
an evaluation/quantification of degrada-
tion, transformation, and immobilization
processes, in order to obtain an integrated
assessment of design and management
requirements for successful assimilation
of a waste in a soil system.
Demonstration of the potential for treat-
ment of a particular hazardous waste in
soil can be addressed using several ap-
proaches. Information can be obtained
from several sources, including literature
data, field tests, laboratory analyses and
studies, theoretical parameter estimation
methods, or, in the case of existing land
treatment units, operating data. In this pro-
ject, specific information obtained from
literature sources included quantitative
degradation, transformation, and immobi-
lization data for identified waste-specific
hazardous constituents in soil systems.
Due to the current lack of a comprehen-
sive technical information base, the U.S.
EPA considers the use of literature infor-
mation only as insufficient to support
demonstration of treatment of hazardous
wastes in soil at the present time.
Specific objectives of this research pro-
ject were to:
(1) Conduct a literature assessment for
each candidate hazardous waste
(API separator sludge, slop oil emul-
sion solids, creosote wood preserv-
ing waste, and pentachlorophenol
(PCP) wood preserving waste) to
obtain specific information pertain-
ing to degradation, transformation,
and immobilization in soil of hazar-
dous constituents identified in each
waste.
(2) Characterize candidate wastes for
identification of specific constitu-
ents of concern; and characterize
experimental soils for assessment of
specific parameters that influence
soil treatability potential.
(3) Conduct laboratory screening ex-
periments using a battery of bio-
assays to determine waste loading
rates (mg waste/kg soil) to be used
in subsequent longer term experi-
ments designed to assess potential
for treatment of each selected
waste in soil.
(4) Develop degradation, transforma-
tion, and immobilization information
for each candidate hazardous waste^
in the two soils selected for study. 1
(5) Develop methodologies for mea-
surement of "volatilization-correct-
ed" degradation rates and partition
coefficients; use the methodologies
developed to generate degradation
kinetics/partition coefficients for a
subset of waste-soil combinations
and for those constituents common
to all wastes.
Objectives 1, 2, and 3 are addressed in
Volume 1 of this report; objectives 4 and
5 are addressed in Volume 2.
Research Approach
Four listed hazardous wastes were
selected for study (Table 1). The wastes
chosen are produced in high volume, con-
tain numerous organic and inorganic con-
stituents, and represent a broad spectrum
of physical, chemical, and toxicological
characteristics.
API separator sludge—(K051)
This waste is generated from primary
settling of wastewaters that enter the oily
water sewer and typically consists of
water, oil, and solids. Solids are largely
sand and coarse silt, but also may contain
significant quantities of hazardous metals,
i.e., chromium and lead. Heavy oils that
settle and become part of the bottom
sludge in an API separator are largely com-
posed of heavy tars, large mutiple
branched aliphatic compounds (paraffins),
polyaromatic hydrocarbons, and coke
fines. Proportions of oily material which
are tar-like, paraffinic or polyaromatic are
largely dependent on the crude source.
Slop oil emulsion solids—(K049)
This waste is generated from skimming
the API separator and typically consists of
approximately 40 percent water, 43 per-
cent oil, and 12 percent solids. Chromium
and lead typically are present in significant
concentrations in the solid phase.
Table 1. Hazardous Wastes Selected for
Evaluation
EPA
Hazardous
Waste
Waste No.
Petroleum Refinery Wastes
API Separator Sludge K051
Slop Oil Emulsion Solids K049
Wood Preserving Wastes
Creosote K001
Pentachlorophenol K001
-------
i Creosote wood preserving waste
-(K001)
Creosote is a distillate from coal tar
made by high temperature carbonization
of bituminous coal. Creosote alone or in
combination with coal tar or petroleum is
a major preservative used in wood treat-
ment. The principal classes of organic con-
stituents present in creosote wastes are
polyaromatic hydrocarbons and phenolics.
Pentachlorophenol (PCP) wood
preserving waste—(K001)
Pentachlorophenol is widely used as a
wood preservative and also has been used
for slime and algae control. The combined
PCP-creosote sludge used in this experi-
mental investigation contained polyaro-
matic hydrocarbons, phenolics, and PCP.
An experimental approach was designed
to test the hypothesis that treatment
would be achieved for each of four listed
hazardous wastes in two soil types and to
evaluate the effect of selected design and
management factors, i.e., waste loading,
on treatment. Therefore, the scope of the
study involved addressing the demonstra-
tion of treatment of hazardous waste us-
ing soil as the treatment medium. The soil
treatment potential for each candidate
waste was evaluated as a function of
waste loading rate, soil moisture, and time.
A combination of chemical analyses and
bioassays was used to characterize end-
points for degradation, transformation,
and immobilization of waste constituents.
Treatment of a hazardous waste refers
specifically to treatment of hazardous con-
stituents contained in the waste. Stand-
ards identified in 40 CFR Part 264.272(c)
(i) refer to Appendix VIM constituents
listed in part 261. Where waste(s) are from
an identified industry with well defined
processes, i.e., petroleum refining, it may
be acceptable to perform analyses for a
subset of Appendix VIII constituents. The
subset of organic constituents selected for
evaluation in these waste-soil interaction
studies included semivolatile polycyclic
aromatic hydrocarbon (PAH) compounds
and the volatile organic constituents
(VOC) benzene, toluene, xylene, ethylben-
zene, and naphthalene for each waste,
with the addition of pentachlorophenol for
the PCP wood preserving sludge.
Two soil types were selected as treat-
ment media to allow evaluation of the ef-
fect of varying soil characteristics on the
extent and rate of treatment. Soil types
were chosen that (1) represented soils
typical of operating land treatment facili-
ties and (2) provided a range of specific
characteristics for evaluating treatment as
a function of soil type. Each soil selected
was characterized for specific properties
considered to be important in influencing
soil treatment processes.
The experimental waste loading rate
(mass/area/application, or mg waste/kg so-
il) was the first design parameter deter-
mined. In order to evaluate the extent and
rate of treatment, sustained soil microbial
activity must be maintained. Therefore,
the impact of an applied waste on indige-
nous soil microbial populations must be
evaluated, especially for any waste con-
taining hazardous constituents specifically
designed to inhibit biological activity, i.e.,
wood preserving wastes. In this study, a
battery of microbial toxicity screening
assays was used to estimate acceptable
initial waste application rates for use in
subsequent bench-scale waste-soil inter-
action studies.
A comparative study of the sensitivity
of five microbial assays: Microtox, soil
respiration, soil dehydrogenase, soil nitrifi-
cation, and viable soil microorganism plate
counts, to pentachlorophenol (PCP) and
slop oil wastes in Kidman sandy loam soil
was performed to evaluate response of
these commonly used assays to identical
waste-soil mixtures.
The degradation potential of hazardous
organic constituents in any waste applied
to soil is critical since biodegradation
usually represents the primary removal
mechanism for such constituents. Degra-
dation coefficient measurements involve
determination of soil concentrations of
specific organic constituents as a function
of time. Degradation was characterized as
a first order kinetic rate process for all con-
stituents evaluated; the first order reaction
rate constant was then used to calculate
half-lives for each constituent. These
calculated half-lives provided quantitative
information for evaluating the extent and
rate of treatment, and for comparing treat-
ment effectiveness for each waste-soil
combination as a function of design and
management factors.
Conversion of hazardous constituents to
less toxic intermediates within the soil
treatment medium also was evaluated. In-
formation concerning the toxicity reduc-
tion of the waste-soil mixture over time
was evaluated using an acute toxicity
assay (Microtox test), and a mutagenicity
assay (Ames Salmonella typhimurium
test).
Evaluation of treatment also involved in-
vestigation of the extent of migration of
hazardous constituents contained in each
hazardous waste. A loading rate based on
degradation potential was selected for
each waste-soil combination; leaching
potential was subsequently characterized
for these loading rates in laboratory
column studies. Partition coefficients
among waste (oil), water, and air for a
subset of organic constituents also were
determined for use as input parameters to
the proposed Regulatory and Investigative
Treatment Zone (RITZ) model that has
been developed by the U.S. EPA Robert S.
Kerr Environmental Research Laboratory
(RSKERL).
Results and Discussion
Characterization and Loading Rate
Selection
Each waste was characterized for poly-
cyclic aromatic hydrocarbons (PAH), vola-
tile organic constituents (VOC), and poly-
chlorinated dibenzo-p-dioxins (PCDD) and
polychlorinated dibenzofurans (PCDF)
using GC/MS, HPLC, and GC instrumenta-
tion. Concentrations of individual PAH
compounds in the waste as determined by
HPLC are presented in Table 2. Results
from VOC analyses for all wastes identi-
fied naphthalene as the prominent peak.
No TCDD was detected (detection limit 10
ppb) in the PCP waste, although other
PCDDs as well as PCDFs were identified.
The highest loading rate for each waste-
soil combination was evaluated for muta-
genic potential using the Ames test with
and without microsomal (S9) activation.
With activation all four wastes exhibited
a positive mutagenic potential in Durant
clay loam soil. Slop oil emulsion solids and
creosote wood preserving waste exhibited
a positive mutagenic potential in Kidman
sandy loam soil; API separator sludge and
PCP wood preserving waste did not exhibit
a mutagenic potential in Kidman soil.
None of the wastes exhibited a muta-
genic potential as measured by the Ames
test without microsomal (S9) activation.
All wastes exhibited a high degree of
water soluble fraction (WSF) toxicity as
measured by the Microtox toxicity test.
Important differences in soil properties
between the two experimental soils in-
cluded organic carbon content (2.88%,
0.5%), pH (6.6, 7.9), and moisture at -1/3
bar (41.6%, 20%) for the Durant clay loam
and Kidman sandy loam, respectively.
Waste loading rates in soil as selected
based on results of Microtox and soil
respiration assays are presented in Table
3. The wood preserving wastes used in
this project exhibited greater levels of tox-
icity than the petroleum refining wastes
used. Loading rates selected were gen-
erally higher for the Durant clay loam than
-------
Table 2. Concentration of Individual PAH Compounds in Wastes Determined by HPLC
Concentration in Waste (mg/kg) *
Compound
Naphthalene
Acenaphthalene
Acenaphthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzofa)anthracene
Chrysene
Benzo(b)fluoranthene
Benzo (k) fluoran thene
Benzotaipyrene
Benzo (ghi)pyrene
Dibenz(a,h)anthracene
Indenod, 2, 3-cd)pyrene
API
Separator Sludge
580 ± 87 (15%)
480 ± 100 (21%)
<12
29 ± 33 (1 14%)
810 ± 140 (17%)
110 ± 27 (25%)
5,500 ± 230 (5%)
6,000 ± 440 (7%)
1,400 ± 58 (4%)
570 ± 310 (54%)
<3
310 ± 62 (20%)
170 ± 73(43%)
<10
40 ± 11 (28%)
61 ± 25 (41%)
Slop Oil
2,500 ± 700 (28%)
<15
<10
440 ± 300 (68%)
3,600 ± 2,100(58%)
480 ± 93 (19%)
18,000 ± 5,000 (28%)
23,000 ± 6,700(29%)
2,000 ± 1, 100 (55%)
1,100 ± 150(14%)
340 ± 140 (41%)
160 ± 42 (26%)
260 ± 200 (77%)
59 ± 18 (31%)
15 ± 1 (7%)
88 ± 19 (22%)
Creosote
28,000 ± 1,200 (4%)
3,600 ± 1,000 (28%)
180,000 ± 40,000 (22%)
23,000 ± 5,900 (26%)
76,000 ± 15,000 (20%)
15,000 ± 6,800 (45%)
72,OOO ± 17,000(24%)
64,000 ± 12,000 (19%)
7,400 ± 1,600 (22%)
8,300 ± 2, 100 (25%)
3,OOO ± 700 (23%)
2,400 ± 460 (19%)
2,700 ± 380 (14%)
1,100 ± 280(25%)
<1,200
820 ± 76 (9%)
Pen tachlorophenol
42,000 ± 28,OOO (67%)
<2,000
< 13,000
<22,000
52,000 ± 6,200 (12%)
1 1,000 ± 6.800 (62%)
46,000 ± 6,200 (13%)
56,000 ± 13,000 (23%)
16,000 ± 2,400 (15%)
6,900 ± 2,200 (32%)
10,100 ± 5,100 (51%)
<300
<280
<100
<250
<60
^Average concentration of three replicate analyses ± one standard deviation (coefficient of variation %).
Table 3.
Waste
V. jste-Soil Loading Rates Selected Based on Microtox
and Soil Respiration Test Results
Loading Rates
Kidman Sandy Loam
Durant Clay Loam
Low Medium High Low Medium High
(% waste wet weight/soil dry weight)
Creosote
Pentachlorophenol
API Separator Sludge
Slop Oil
0.4
0.075
6
6
0.7
0.15
9
8
1.0
0.3
12
12
0.7
O.3
6
8
1.0
0.5
9
12
1.3
0.7
12
14
the Kidman sandy loam, thus indicating a
difference with respect to the effect of soil
type on waste-soil interactions.
Results from a battery of microbial as-
says conducted using PCP and slop oil
wastes indicated a good correlation be-
tween the Microtox, soil nitrification, and
soil dehydrogenase assays. Highly variable
results were obtained with soil respiration
(carbon dioxide evolution) and viable plate
count assays. The latter two assays ap-
peared to be much less sensitive to the
waste loadings used.
A series of experiments were conducted
to evaluate the PAH extraction procedure
using the Tekmar Tissumizer. Results for
spiked recoveries of 16 PAH compounds
from Durant clay loam and Kidman sandy
loam soils are presented in Table 4. Four
concentration levels were used to bracket
the range of PAH concentrations in waste-
soil mixtures from the beginning (high
concentration) to the termination (low
concentration) of the degradation
experiments.
Information presented in Table 4 indi-
cates consistent and generally high re-
coveries for all 16 PAH compounds from
both soil types. Also, recoveries did not
vary greatly and were relatively high
through a three-log change in soil PAH
concentrations. Thus, the soil extraction
procedure used in this project appeared to
provide consistent and relatively high ex-
traction efficiencies for both soils over the
range of concentrations of concern.
Treatment Results
Results of degradation studies for all
four wastes in both soils generally indi-
cated an increase in PAH half-life with in-
creasing molecular weight or compound
size. This observation is generally consis-
tent with results obtained in other studies
for the PAH class of compounds in soil
systems. However, soil half-lives for some
higher molecular weight PAH compounds
in these complex wastes were observed
to be lower than half-lives reported in the
literature for PAH compounds only, i.e.,
without the waste matrix. The observed
variation in degradation rates and half-lives
obtained for PAH constituents in these
studies may be due, in part, to the diffi-
culty in accurately analyzing individual
constituents in soil mixed with complex
environmental mixtures. These degrada-
tion rates and half-lives observed in these
studies may be lower, however, as a result
of cooxidation/cometabolism or other
matrix-induced phenomena.
An increase in soil moisture content
from -2 to -4 bars to -1/3 to -1 bars gen-
erally was associated with a decrease in
PAH compound half-life for waste-soil
mixtures.
Results also indicate that half-life values
for constituents in each petroleum waste
were similar for some compounds even
though waste loading rates were different.
These results would be expected if de-
gradation followed first order kinetics.
Half-life values for waste constituents
in each wood preserving waste also were
similar even though loading rates were dif-
ferent. These results are similar to those
observed for the petroleum wastes, and
are expected if degradation processes
follow first order kinetics.
After the first experimental period of ap-
proximately 280 days, wastes were reap-
plied to the soil according to the follow-
ing schedule: 1) waste originally loaded at
the medium rate was reloaded at the medi-
um rate (M/M); 2) waste originally loaded
at the low rate was reloaded at the high
rate (L/H); 3) nonacclimated soil was
loaded at the high rate of waste applica-
tion (N/H); and 4) waste-soil mixtures
originally loaded at the high loading rate,
but not reloaded (H/NR). Results from
reapplication experiments were converted
to first order reaction rate constants and
half-life values. A subset of waste-soil mix-
tures for each soil and waste type was
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Table 4. Tissumizer Extraction Recovery Results for PAH Compounds in Kidman and Durant Soils'
Kidman Sandy Loam
Soil concentration in mg/kg
Compound
Durant Clay Loam
Soil concentration in mg/kg
1000
1OO
10
1
7000
700
70
Napthalene
Acenaphthalene
Acenaphthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benzofalanthracene
Chrysene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Dibenz(ah)anthracene
Benzo(ghi)pyrene
lndeno(1,2,3-cdlpyrene
92.3 13.8)
89.7 14.7)
82.3 13.2)
98.0 11.01
98.7 (1.5)
98.7 1 1.5)
95.0 12.7)
106.3 13. 1)
97.0 (2.0)
95.6 (1.5)
-
-
-
-
96.0 (0.0)
82.0 (4.4)
80.0(1.7)
96.7 (0.6)
99.3 (0.6)
89.3 (1.5)
99.3 (1.2)
107.7 (0.6)
97.3 (1.2)
97.0 (1.0)
61.0 (0.0)
104.0(1.0)
75.3 (2.5)
101.7 (2.1)
91.0(0.0)
97.0 (1.0)
86.3 (14.6)
41.7
68.7
96.0
99.3
82.0
97.0
103.0
97.3
96.7
64.0
103.7
66.3
103.3
90.7
98.3
(25.5)
13.2)
(1.7)
(2.1)
(3.0)
(0.0)
(1.0)
(2.3)
(2.1)
(1.0)
(1.5)
(4.7)
(6.4)
10.6)
(1.5)
-
-
103.5 (5.0)
110.0 (0.0)
57.7 (2.5)
85.3 (2. 1)
73.7 (4.0)
96.3 15. 1)
94. 7 (3. 1)
87.7 (1.5)
105.0(2.7)
61.7 (3.1)
78.0 (8.5)
102.0(2.7)
100.0 (2.0)
99.0
87.3
86.7
98.7
99.0
94.3
96.0
107.0
97.3
96.7
-
-
-
-
-
-
(3.0)
(7.2)
(3.1)
(0.6)
(1.0)
(7.2)
(0.0)
(2.7)
(1.2)
10.6)
111.7
89.3
86.3
97.7
99.0
93.0
100.3
108.0
98.7
86.3
61.3
104.3
79.3
103.3
92.7
98.3
(5.0)
(8.1)
(11.2)
(1.5)
(1.0)
(2.7)
(2.3)
(3.6)
(1.2)
(0.6)
(0.6)
(1.5)
(0.6)
(3.2)
(1.2)
(0.6)
158.3 (8. 1)
78.5 (5.0)
77.5 (5.0)
94.3 (4.0)
98.7 (2.5)
86.7 (3.5)
98.7 (1.5)
105.0 (5.3)
99.0(1.7)
98.0 (1.0)
63.3 (1.2)
105.0 (2.0)
61.7 (2.1)
101.3 (4.0)
90.3 (2.5)
98.3 (1.2)
.
-
-
94.5 (7.8)
115.3 (7.2)
65.0 (5.3)
88.0 (16.5)
80.0 (24.3)
100.0 (1.4)
97.0 (1.7)
86.7 (2.1)
99.7 (2.5)
68.3 (10.0)
86.3 (2.3)
111.0 (4.6)
108.0 (0.0)
* Table values represent average recoveries of triplicate extractions at each loading level with standard deviations in parentheses.
selected for detailed characterization of
degradation. The subset was evaluated for
approximately an additional 100 days.
For the petroleum wastes, reapplication
did not appear to alter the half-life values
for PAH constituents. Neither an inhibiting
nor stimulating effect was observed. For
the wood preserving wastes, there is no
trend that would suggest a change in half-
life with one reapplication.
PAH degradation results for wastes in-
cubated in Kidman sandy loam soil gener-
ally followed the trend observed for waste
treatment in Durant clay loam soil. PAH
degradation generally appeared to be in-
fluenced by molecular weight or com-
pound ring size. Variation in the data ob-
tained for degradation increased when
waste was reloaded.
Pentachlorophenol degradation also was
evaluated for the PCP wood preserving
waste. Kinetic information is presented in
Tables 5 and 6 for PCP waste in Durant
clay loam soil and Kidman sandy loam soil,
respectively. Half-life values are similar
(257 days and 204 days) for PCP initially
loaded at the high rate in both soils and
not reapplied. Acclimation of Kidman
sandy loam soil to PCP may have occur-
red as indicated by comparing results in
Table 6 for experiments N/H and H/NR in
Kidman soils. Both sets of experiments
received PCP waste at the high loading
rate (0.3%). However, PCP in mixtures in-
cubated for 400 days (H/NR) had a half-
life of 204 days, while PCP in mixtures in-
cubated for 164 days (N/H) had a half-life
of 330 days. Evidence for acclimation is
also indicated in the experimental set (L/H)
initially receiving the low loading rate
(0.075%) and reloaded at the high rate
Table 5. Degradation Kinetic Information
for Pentachlorophenol in Pen-
tachlorophenol Wood Preserving
Waste Reapplied to Durant Clay
Loam Soil at -1 Bar Soil
Moisture
Loading
Rate
M/M+
H/NR*
r *
°0
(mg/kg)
4.0E2
2.3E2
k
(day- 1)
0.0016
0.0027
tl/2
(days)
433
257
after waste incorporation into soil.
+ M/M = originally loaded at medium rate
(0.5%), reloaded at medium rate.
*H/NR = originally loaded at high rate
(0.7%), not reloaded.
Table 6. Degradation Kinetic Information
for Pentachlorophenol in Pen-
tachlorophenol Wood Preserving
Waste Reapplied to Kidman
Sandy Loam Soil at -1/3 Bar
Soil Moisture
Loading
Rate
M/M+
L/H*
N/H*"
H/NR**
r *
°0
(mg/kg)
2.7E2
1.6E2
_ + +
1.8E2
k .
(day~ 1)
0.0024
0.0046
0.0021
0.0034
t,/2
(days)
289
151
330
204
after waste incorporation into soil.
+M/M = originally loaded at medium rate
(0.15%), reloaded at medium rate.
*L/H - originally loaded at low rate
(0.075%), reloaded at high rate
(0.3%).
* *N/H = nonacclimated soil loaded at high
rate (0.3%).
+ + = not analyzed.
**H/NR = originally loaded at high rate
(0.3%), not reloaded.
(0.3%). The half-life for PCP in this soil
was 151 days. Acclimation of soil micro-
organisms to PCP would be expected to
result in lower half-life values when waste
is reapplied.
Transformation of hazardous wastes in
all waste-soil combinations was evaluated
by measuring changes in the toxicity of
the water soluble fraction (WSF) of waste-
soil mixtures as indicated by the Microtox
test. An increase in WSF toxicity was
observed for all waste-soil mixtures evalu-
ated during the first experimental period,
and a decrease in WSF toxicity was gen-
erally observed during the second experi-
mental period. These results were consid-
ered to be indicative of the formation and
subsequent degradation of toxic interme-
diate constituents.
The Microtox assay proved to be an ex-
tremely sensitive assay that did not corre-
late with gross degradation indicators
such as soil respiration studies, and there-
fore could not be used to positively iden-
tify the level at which soil biodegradation
was inhibited. The WSF toxicity results did
indicate, however, that transformation of
the waste occurred for all waste-soil com-
binations. Since the WSF may contain haz-
ardous intermediates, it may be concluded
that lower loading rates will be required if
the treatment evaluation criterion is com-
plete detoxification of the waste-soil
mixture.
Results of mutagenicity evaluations for
soil detoxification of petroleum refinery
wastes indicated a reduction from muta-
genic to nonmutagenic activity with treat-
ment time for API separator sludge in
Durant clay loam soil and for slop oil emul-
sion solids incubated in Durant clay loam
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and in Kidman sandy loam soils. Wood
preserving wastes, however, were not ren-
dered nonmutagenic after 400 days of soil
incubation in Durant clay loam soil at
waste loading rates of 1.3 percent and 0.7
percent for creosote and PCP wastes, re-
spectively. However, no mutagenicity was
detected at a loading rate of 0.3 percent
PCP waste in Kidman sandy loam soil, and
the initial positive mutagenic potential for
a loading rate of 1.0 percent creosote
waste was reduced to a nonmutagenic
level with a treatment time of 400 days.
Immobilization of hazardous waste was
measured using one bioassay, the Micro-
tox test, of laboratory column leachates.
Microtox test results indicated the
presence of little toxicity in leachates from
petroleum wastes incubated at the high
loading rates in both Durant clay loam and
in Kidman sandy loam soils. Leachates pro-
duced from creosote and PCP loaded col-
umns exhibited definite toxicity to Micro-
tox, thus indicating the potential for
leaching of water soluble toxicants that
should be considered when defining waste
loading rates for these experimental soils.
The absence of Microtox test toxicity of
some leachates did not conclusively dem-
onstrate that leachates were free of toxic
constituents.
Partition coefficients that were deter-
mined for PAH and volatile constituents of
all four wastes indicated highest partition-
ing of constituents into the oil (waste)
phase. Relative concentrations between
water and oil (waste) phases for PAH
constituents were generally 1:1000 to
1:100,000, with the higher ratios observed
for the petroleum wastes. Relative con-
centrations among air:water:oil (waste)
phases for volatile constituents were
generally 1:100:100,000.
Conclusions
Specific conclusions based on objec-
tives and results of this research project
include:
(1) Literature assessment of specific
hazardous constituents experimen-
tally identified in each candidate
waste indicated a potential for treat-
ment in soil systems.
(2) Characterization of all candidate
wastes by GC/MS, GC, and HPLC
identified the PAH class of semi-
volatile constituents as common to
each waste. In addition, the PCP
wood preserving waste contained
pentachlorophenol and some
dibenzo-p-dioxins and dibenzofur-
ans; however, no tetrachlorodiben-
zodioxins were detected at a detec-
tion limit of 10 ppb.
(3) A comparative study of the sen-
sitivity of five microbial assays for
selection of initial waste loading
rates indicated that Microtox, soil
dehydrogenase, and soil nitrification
assays were the most sensitive to
the presence of hazardous wastes,
and would result in selecting lower
loading rates. Soil respiration and
viable soil microorganism plate
counts were much less sensitive to
hazardous waste application, and
would result in selecting higher
loading rates.
(4) Based on screening assay results,
initial loading rates for petroleum
refinery wastes were indicated to be
an order of magnitude higher than
for wood preserving wastes.
(5) A methodology was developed for
measurement of "volatilization-
corrected" degradation rates in soils
in order to more accurately evaluate
degradation as a treatment mecha-
nism. For the semivolatile PAH com-
pounds studied, volatilization was
important only for naphthalene.
(6) A methodology was developed for
measurement of partition coeffi-
cients for hazardous constituents
among waste (oil), water, and air
phases. It was not possible to
measure the partitioning between
the water soluble extract and soil
because the very low water solubil-
ities of the aromatic hydrocarbons
and the very high affinity of these
constituents for soil resulted in
reduction of constituent concentra-
tions in the water soluble extract to
below detection limits. The method-
ology proved useful for obtaining
partition coefficients for waste
(oil)/water (K0), air/water (Kh), and
air/waste (oil) Koa), for volatile con-
stituents and for waste (oil)/water
for semivolatile constituents.
(7) PAH constituents contained in each
of the four wastes investigated
were degraded under conditions of
initial waste application to nonac-
climated soils as well as when
wastes were reapplied to soils. In
general, PAH degradation did not
appear to be influenced by varia-
tions in soil type or loading rates
used in this study; however, PAH
degradation in petroleum refinery
wastes generally exhibited higher
rates than in wood preserving
wastes.
(8) All waste-soil mixtures tested ex-
hibited an initial increase in WSF
toxicity followed by a decrease in *
toxicity with incubation time. The I
pattern of WSF toxicity with time
was considered to be an indication
of formation and degradation of
toxic intermediates.
(9) Partition coefficients determined for
PAH and volatile constituents con-
tained in each of the wastes eval-
uated demonstrated highest parti-
tioning of constituents into the oil
(waste) phase. Relative concentra-
tions between water and oil (waste)
phases for PAH constituents were
generally 1:1000 to 1:100,000, with
the higher ratios observed for the
petroleum wastes. Relative concen-
trations among air:water:oil (waste)
phases for VOCs were generally
1:100:100,000.
Recommendations
The following recommendations are
made in regards to conducting future soil
treatability studies for hazardous wastes:
(1) The use of chemical analyses alone
appears to be insufficient to charac-
terize treatability potential of a
hazardous waste in soil. Use of
chemical analyses alone fails to ac-
count for interactions of compo-
nents in a waste and the production
of toxic/mutagenic metabolites.
Use of bioassays to characterize the
degradation, transformation and im-
mobilization processes should be
used to complement chemical
analyses information.
(2) Careful attention in future soil
treatability studies should be given
to potential fate, transport and ef-
fects of intermediate products
formed during waste-soil interac-
tions. Information obtained con-
cerning degradation, transforma-
tion, and immobilization of hazard-
ous constituents should be used to
aid in selecting waste loading rates
to be used in field evaluation study.
(3) When determining partition coeffi-
cients (K0, Kh, KD, Kao) for evalua-
tion of immobilization processes in
waste-soil mixtures, several differ-
ent ratios of waste:water volumes
and several water soluble fraction
volumes:soil weights should be
used to generate partition iso-
therms with several points in order
to evaluate the ranges of linearity
for the isotherm and partition coef-
ficient values. Determination of par-
tition coefficients between soil and
6
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water soluble extract of the waste
(KD) will require larger amounts of
waste and water than used in this
investigation to generate larger
amounts of water soluble fractions.
The full report was submitted in fulfill-
ment of Cooperative Agreement No.
CR-810979 to Utah State University under
sponsorship of the U.S. Environmental Pro-
tection Agency.
R. C. Sims, J. L. Sims, D. L. Sorensen, W. J. Doucette, and L. L Hastings
are with Utah State University, Logan, UT 84322.
John £. Matthews /s the EPA Project Officer (see below).
The complete report consists of two volumes, entitled "Waste/Soil Treatability
Studies for Four Complex Industrial Wastes: Methodologies and Results,"
"Volume 1. Literature Assessment, Waste/Soil Characterization, Loading
Rate Selection," (Order No. PB87-111 738/A S; Cost: $ 18.95)
"Volume 2. Waste Loading Impacts on Soil Degradation, Transformation, and
Immobilization,"(Order No. PB 87-111 746/AS; Cost: $24.95)
The above reports will be available only from: (costs subject to change)
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
P.O. Boz1198
Ada, OK 74820
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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Official Business
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