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UNCLASSIFIED
SECURITY CLASSIFICATION Of THIS PAGCrWiOT O*« Stil»r»4)
Uniformly ring labeled 14C-TNT or 14C-RDX were used in the laboratory studies. A
50% reduction in TNT concentrations was demonstrated after three weeks of
composting with a total reduction of 82.6% at the end of six weeks. No significant
quantities of ^CC^ were evolved indicating that composting did not result in
cleavage of the ring structure of the TNT molecule. Reduction products normally
fomet? from aerobic trans format ion of TOT were not detected after three weeks of
composting. Trace quantities of 4-anino-2,6-dinitrotoluene and 2-amino-4,6-
dinitrotoluene were found in one of three replicate composts after six weeks of
composting. The RDX laboratory composts showed a reduction in the RDX concentra-
tion of 31.2% after three weeks of composting and a total reduction of 78.3% after
six weeks of composting. Significant amounts of ^COi were produced by the RDX
compost indicating that cleavage of the RDX molecule occurred during composting.
The greenhouse compost studies demonstrated a very rapid decrease in the TNT
concentration. At the three week sampling time, the TNT concentration had been
reduced by 99.9%. Analysis of the four week TNT compost extract confirmed that the
TNT concentration in the composted material was below the detection limit of 16.9
ppm. Greenhouse composting of RDX resulted in a 61% reduction in the RDX
concentration after three weeks with a total reduction of 82% following six weeks
of composting.
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SUMMARY
The objective of this study was to determine the extent to which TNT and
RDX concentrations are reduced by composting under controlled conditions in the
laboratory over a period of six weeks. A second objective was to determine if
bench-scale composting studies accurately simulate the activity of larger
composts by comparison of parallel studies monitoring TNT and RDX disappearance
in laboratory scale (50 g dry weight) and greenhouse (10 kg dry weight) composts.
An additonal objective was to determine the leachability of TNT or RDX from
compost.
A portion of the explosives used in the laboratory studies contained a
1ZlC-tracer (^C-TNT or uniformly ring labeled 14C-RDX). Each explosive was added
to an initial concentration of 1% in the composts. Composts (50 g dry weight)
were incubated at 55°C with continuous aeration. Offgases were monitored for
^CC>2, volatile l^C-amines and other volatile l^C-organics. Composted material
was solvent extracted after three and six weeks of composting. Extracts were
monitored by liquid scintillation counting for ^C-activity. Thin layer chroma-
tography and autoradiography were used to determine the portion of the
radioactivity present in the extract as the parent molecule and to isolate l^C-
containing solvent extractable products from composting of the ^C-labeled
explosives.
Greenhouse scale composts (10 kg dry weight) contained production grade
TNT (2% by weight) or RDX (1%) by weight and composted for four to six weeks.
Aerobic conditions were Maintained in these composts by a forced aeration system
and by frequent" mixing. No external energy was supplied to heat these composts.
Each compost was sampled after three weeks of composting and after four or six
weeks of composting. The samples were extracted and the extracts were analyzed
by gas chromatography to determine the concentration of explosives remaining in
the compost material.
Composting under laboratory conditions resulted in a decrease in the TNT
concentration of 50% after three weeks and a reduction of 82.6% at the end of six
weeks. Significant quantities of ^C02 were not evolved by these composts
indicating that cleavage of the ring structure did not occur during composting.
TNT reduction products usually formed in the biotrans formation of TNT were not
detected after three weeks of composting. Trace quantities of 4-amino-2,6-
dinitrotoluene and 2-amino-4,6-dinitrotoluene were found in one of three
replicate composts after six weeks of composting.
RDX concentrations were reduced by 31.2% after composting for three weeks
under controlled laboratory conditions. A reduction of 78.3% in the RDX
concentration was demonstrated after six weeks of composting. 1^CC>2 was produced
by these composts in significant amounts indicating that cleavage of the RDX
molecule occurred during composting.
111
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A very rapid decrease in TNT concentration was demonstrated in the
greenhouse compost studies. After three weeks of composting, the initial TNT
concentration of 20,000 ppm had been reduced by 99.9%. Analysis of the four week
TNT compost extract confirmed that the TNT concentration in the composted
material was below the detection limit. Breakdown of RDX in" the greenhouse
compost was initially more rapid than in laboratory composts. After three weeks
of composting, RDX levels in the greenhouse composts were reduced by 61%. Total
reduction of RDX by composting for six weeks averaged 82%.
Results from the laboratory and greenhouse composts indicate that both
RDX and TNT concentrations are rapidly decreased by composting. Explosives
levels are reduced by 80% or more within six weeks. Data from laboratory
composting in these studies provided a good estimate of the breakdown of
explosives in larger scale composts.
The leachate study was performed under conditions designed to illustrate
a "worst case" example. The soil used in the study was selected to have a
relatively low capacity to absorb and retain organics such as TNT or RDX and the
24-hour extraction would likely result in TNT and RDX concentrations far greater
than would be found following rainfall and leaching from an outdoor compost pile.
Analysis of the RDX compost leachate at time zero showed that 7.4% of the RDX
(approximately 124 ppm) was leached into the water extract. A significant
decrease in RDX content was observed in the 3 week compost leachate (52.5 ppm) and
in the 6 week compost leachate (13 ppm). The decrease in the RDX concentration
in the leachates corresponds to the biodegradation of this explosive during the
composting period. Analysis of the TNT compost leachate showed that TNT was not
leached into the water extract in detectable amounts from fresh compost
materials. The three-week TNT compost leachate contained 98 ppm TNT and the six-
week TNT compost leachate contained 1.4 ppm TNT. These results indicate that
adsorption of TNT to compost materials is altered during composting to allow
increased leaching of TNT into the extract by three weeks. The subsequent
decrease in TNT concentrations in the 6-week leachate corresponds to the
disappearance of TNT during the composting period.
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TABLE OF CONTENTS
I. Introduction 1
A. Background 1
B. Objectives 2
II. Materials, Equipment and Analytical Methods 3
A. Equipment 3
B. Compost Materials 3
1. Carbon and Nitrogen Source 3
2. Seed Compost 3
3. Soil 4
4. TNT and RDX 4
5. 14c-Labeled Explosives 4
C. Analytical Methodology 6
1. Development of Procedures to Extract TNT from
Compost 6
2. Development of Procedures to Extract RDX from
Compost 8
3. • Quantitative Analysis of TNT 8
4. Quantitative Analysis of RDX 9
5. Liquid Scintillation Counting 10
6. I4c-Product Identification and Quantification . . 12
7. ^C-Detection Limit by TLC 12
8. Carbon and Residual - ^C Determinations .... 13
9. Moisture Determinations 13
10. pH Determinations 14
11. Nitrogen Analysis 14
12. Oxygen and Carbon Dioxide Determinations .... 14
III. Preliminary TNT Laboratory Compost 15
A. Experimental Procedures 15
B. Results of Preliminary TNT Composting Study 18
1. Routine Mointoring of Composts 18
2. Extraction of Three-Week Preliminary Laboratory
14C-TNT Composts 18
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Page
3. Analysis of Preliminary Compost Extracts 18
4. Conclusions Based on Preliminary TNT Compost
Experiment 23
IV. Laboratory Composting of TNT and RDX 25
A. Compost Set-Up 25
1. Soil Spikes 25
2. Laboratory Composts 25
B. Results of Laboratory Compost Studies 27
1. Routine Monitoring of Composts 27
2. Analysis of Control Compost 31
3. Analysis of ^C-labeled Composts 34
4. Statistical Analyses of Data from Laboratory
Composts 40
C. Discussion and Conclusions Based on Laboratory Composting
Data 43
V. Greenhouse Composting 46
A. Greenhouse Compost Set-Up and Sampling ......... 46
1. Soil Spikes 46
2. Construction of Compost Chambers 46
3. Set-Up of Greenhouse Composts 46
4. Sampling Procedure 48
B. Results 48
1. Routine Monitoring of Greenhouse Composts .... 48
2. Compost Extraction and Analysis 53
C. Discussion and Conclusions 53
VI. Leachate Study 59
A. Preliminary Study 59
1. Water Holding Capacity 59
2. Clarification of Aqueous Extract 62
B. Leachate Study 62
C. Results 62
D. Conclusions 64
VII. References 65
VI
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Appendix A Synthesis of 14C-Labeled RDX
Appendix B Analysis of TNT in Compost - Quantitative ..
Appendix C Analysis of RDX in Compost - Quantitative ..
Appe.idix D Temperature Records for Laboratory Composts .
Appendix E Temperature Records and Materials Added to Green
house Composts
Appendix F Analysis of Greenhouse Compost Atmospheres for
Oxygen and Carbon Dioxide
Appendix G Photograph of a Greenhouse Compost
LIST OF TABLES
Number
1. Results of Thin Layer Chromatographic Analysis of ^C-
Stock
2. Thin Layer Chromatographic Analysis of ^C-RDX Stock .
3. Detection Limit Data for ^C on TLC Plates
4. Daily Temperature Readings for the Preliminary Composts
5. l^C-Activity in NaOH Traps from the Preliminary Composts
6. l^C-Recovery in H2S04 Traps from the Preliminary
Composts
7. TLC Solvent Systems Evaluated for TNT Analysis
8. Summary of Laboratory Compost Systems
9. Quantity of RDX and TNT Added to Individual Laboratory
Composts
10. Average Cumulative Recoveries of ^C-Activity from H2S04
Traps
11. Oxygen and Carbon Dioxide Levels in Control Compost
Atmospheres
12. Analysis of Control Composts for Laboratory Study . .
67
71
79
87
91
95
101
5
7
13
20
21
22
24
26
28
31
32
33
VII
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Number Page
13. Summary of 14C Recovered from 14C-TNT Laboratory Composts. 35
14. Summary of ^C Recovered from ^C-RDX Laboratory Composts. 35
15. !4c Recovery from TNT Laboratory Compost Extracts ..... 37
16. 14C in Acid and Basic Methanol Extracts from 14C-TNT
Laboratory Composts ................... 38
17. Analysis of Variance Tables for the TNT Laboratory
Composts ......................... 41
18. Analysis of Variance Tables for the RDX Laboratory
Composts ......................... 42
19. Average Recovery of 14C as TNT from Compost After 0, 3,
and 6 Weeks of Composting ................ 44
20. Greenhouse Compost Ingredients ............. 49
21. Moisture Contents of Greenhouse Compost and Compost
Components ....................... 50
22. RDX and TNT Concentrations in Greenhouse Composts at Time
Zero Sampling ...................... 51
23. Analysis of Variance Examining Subsample Size for Green-
house Scale RDX and TNT Composts .......... . . . . 52
24. TNT Concentration in Greenhouse Compost Material .... 54
25. RDX Concentration in Greenhouse Compost Material ... 54
26. Quality Control: TNT Compost Sampling .... ....... 55
27. Quality Control: RDX Compost Sampling .......... 56
28. Analysis of Variance for TNT and RDX Levels in Greenhouse
Composts ......................... 57
29. Summary of Leachate Compost Studies ........... 60
30. Absorption of Water by Composted Material ........ 61
D-l. Laboratory Compost Temperature Records ......... 89
F-l. Average Levels of 02 and C02 in Greenhouse Compost
Atmospheres ....................... 99
Vlll
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LIST OF FIGURES
Number Page
1. Quench Curve 11
2. Schematic of ^^C-Bench-Scale Composting Apparatus .... 16
3. Picture of a Bench Scale Composting Apparatus 17
4. Schematic of Unlabeled (Control) Bench-Scale Composting
Apparatus 19
5. Schematic for Monitoring Laboratory Composts 29
6. Cumulative Percent ^C Recovered as ^C02 from '•**C-
labeled RDX in Compost 30
7. Separation of 14C-TNT by TLC 36
8. TLC Analysis of Acidic and Basic Extracts of 14C-TNT
Laboratory Compost 39
9. Schematic of Greenhouse Compost Chamber 47
10. Comparison of Compost Temperatures for Leachate Study . . 63
£-1. Temperature Profiles and Material Additions for RDX Green-
house Composts 93
E-2. Temperature Profiles and Material Additions for TNT Green-
house Composts 94
E-3. Temperature Profiles and Material Additions for Control
Greenhouse Composts 95
G-l. Photograph of a Greenhouse Compost 101
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I. INTRODUCTION
A. Background
The manufacture and handling of explosives such as TNT and RDX has
resulted in contamination of soils and sediments in areas where these activities
have taken place over extended periods of time. In general, the concentrations
of RDX and TNT in soils are in the low ppm range. Lagoon sediments, however,
contain large concentrations of these explosives, i.e. up to 10% by weight.
These lagoons have been used for wastewater disposal from shell loading and
cleaning operations and, although the wastewaters generally contain less than
100 mg/L of the explosives, over the years the explosives have precipitated out
of the water and collected in the sediment of the lagoons.
In a review of the literature to evaluate biological degradation of
explosives as a potential cost-effective method for decontamination of soils
and sediments, it was found that microbial degradation of RDX proceeds slowly or
not at all under aerobic conditions. Rapid degradation of RDX does occur under
anaerobic conditions. TNT is biotransformed by microorganisms under aerobic
conditions, but no evidence for biodegradation (ring cleavage) was reported.
Biotrans formation of TNT results in a variety of reduction products. Some of
these products are environmentally unacceptable. The literature review
identified composting as a biological method with potential for low-cost
decontamination of soils and sediments.
Composting is a process of controlled biological degradation in which
almost any degradable organic substance may be converted through microbial
activity to a product with the general appearance and many of the character-
istics of a fertile soil. The compost environment is radically different from
that found in aerobic soil and sediments because of the elevated temperatures
and the variations in active microbial populations. Mesophilic organisms
thrive when compost tmeperatures range from normal ambient temperatures to
45°C. When the compost temperature exceeds 45°C, thermophilic organisms
proliferate and tolerate relatively high temperatures. Historically compost has
been used in agriculture to convert organic wastes into a product useful as
fertilizer and/or soil conditioner. Composting can occur over a
wide range of conditions in which a natural biological process is stimulated to
decompose complex organic molecules into simpler compounds through the growth
and activity of bacteria, actinomycetes and fungi. The microorganisms use a
portion of the carbon and nitrogen in the compost materials for synthesis of
microbial biomass and convert chemical energy into heat through respiration.
The heat produced increases the temperature of the composting mass and
evaporates moisture. Composting can occur in an aerobic mode over a wide range
of moisture contents. The moisture content must be at least 35% for optimal
composting although excessive moisture may result in displacement of air from
pore spaces by water and may lead to anaerobic conditions. Accelerated aerobic
composting can be achieved by forced aeration in which compost materials are
mixed and bulking materials are added as needed.
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Composting as a technique for disposal of hazardous materials in soils
and sediments is applicable in almost any environment. In situ composting
requires only bulk materials (to provide sufficient pore space for aera-
tion), proteinaceous material (for carbon and nitrogen sources), water and air;
materials which are readily available in almost any locale. Composting for
decontamination of soil or sediment is relatively easy. The soil or sediment is
thoroughly mixed with the compost materials. The maximum amount of soil in the
mixture will depend on the concentration of the hazardous material in the soil
and the type of soil. The concentration of hazardous material must not be so
high as to inhibit the growth of the microbial populations. The type of soil can
also influence the effectiveness of the compost in degrading hazardous
materials. The texture and the organic content of the soil will determine how
readily the soil disperses in the compost. Ideally the soil thinly coats the
organic bulk of the compost, thus exposing individual particles and small
aggregates of soil to the microbial populations. Soils with high clay and/or
organic matter contents may be relatively sticky and tend to clump rather than
disperse. The absorptive properties of the the soil may present an additional
complication, i.e. the soil may bond the hazardous materials strongly enough to
inhibit microbial attack. The interaction between soil, the hazardous material,
and the microbial population is difficult to predict; however, in most
situations it is not expected to significantly retard degradation of the
hazardous waste. Contaminated water could also be decontaminated in this system
by using this water as the source of moisture for the compost pile.
This report presents the results of laboratory-scale and greenhouse
scale composting experiments for decontamination of soils contaminated with TNT
or RDX. The report is organized in the following manner. The basic materials
used in the study and the analytical methods are discussed in Section II.
Section III presents the Preliminary TNT Laboratory Compost. Laboratory
Composting of TNT and RDX and Greenhouse Composting are presented in Sections IV
and V, respectively. The final section (VI) contains the Leachate Study.
B. Objectives
The primary objective of this study, Composting of Explosives, was to
determine the extent to which TNT and RDX concentrations are reduced by
composting under controlled conditions in the laboratory over a period of six
weeks. A second objective was to determine if bench-scale composting studies
accurately simulate the activity of a larger-scale compost by comparison of
parallel studies monitoring TNT and RDX disappearance in laboratory scale (50 g
dry weight) and greenhouse (10 Kg dry weight) composts. An additional objective
was to determine the leachability of TNT or RDX from the compost. Identifica-
tion of the breakdown products of TNT and RDX under compost conditions and
evaluation of the toxicity of the products or leachates were not with-
in the scope of this task.
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II. MATERIALS, EQUIPMENT AND ANALYTICAL METHODS
A. Equipment
The following major pieces of equipment were utilized in this study:
Hewlett-Packard 5880A Gas Chromatograph with electron
capture detector, computer controller, integrator and
autosampler
Varian 3700 Gas Chromatograph with thermoconductivity
detector, computer controller, and integrator
Beckman LS7500 Liquid Scintillation Counter
Greenhouse with temperature control
Incubator, 55°C
Water bath, 37°C
Ball Mill
Virtis Lyophylizer
Hoskins Electric Furnace
B. Compost Materials
1. Carbon and Nitrogen Source
The composts used in these studies were primarily composed of a
50:50 (by weight) mixture of hay and horse feed. Alfalfa was selected as the hay
to be used because of its high leaf to stem ratio and its high protein content.
Baled alfalfa hay was obtained and chopped into segments 40 cm (1.6 inches) or
less. The horse feed used was Purina Sweetena. This feed appeared to contain
cracked corn, oats, finely ground pelletized hay and molasses. The nitrogen
content of both the hay and horse feed was sufficiently high so as not to limit
microbial activity.
2. Seed Compost
An alfalfa hay - Purina horse feed compost was maintained in an
active state to supply microorganisms to seed into freshly started laboratory
and greenhouse composts. This compost was initiated with a small quantity of
sewage sludge as a seed. As the readily available nutrients in this compost were
depleted, a fraction of the compost was disposed of and additional hay and horse
feed were added. This compost was aerated by mixing every 1 to 3 days.
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3. Soil
Soil was used as a carrier to mix the explosives into the compost.
The soil used was a Lakeland sand. Prior to use, the soil was air dried and
sieved (2 mm) to remove pebbles, rocks, and large pieces of plant material. Some
physical and chemical analyses of this soil are as follows:
% sand 95.1
% silt 3.0
% clay 1.9
% organic matter* 1.0
pH1 6.7
A soil composed primarily of sand with a low organic matter content would not be
expected to bind to or strongly interact with, TNT or RDX. This soil was
selected to minimize the possible effects of adsorption on the availability of
RDX and TNT for microbial attack in the compost.
4. TNT AND RDX
The TNT and RDX used to spike the composts were production
grade explosives. Near saturated solutions of TNT and RDX were maintained in
acetone as a stock for addition to compost. The stock was protected from light
and stored at ambient temperatures. TNT or RDX concentrations were determined
by diluting a subsample of the stock for analysis by gas chromatography (GC) .
The analytical methods are described in Section IIB. No attempt was made to
characterize impurities or examine their metabolism in compost.
5. ^C-Labeled Explosives
The purity of ^C-labeled TNT and RDX was determined by thin layer
chromatography and autoradiography. All spots on the chromatograph, spots
identified by radiography, visible spots and spots visible under ultraviolet
light, were scraped into vials for liquid scintillation counting.
Uniformly ring labeled l^C-TNT was obtained from Pathfinder Labor-
atories. Purity of the ^C-label was determined by developing separate
chromatographs in two solvent systems. The results are given in Table 1. Using
benzene:toluene:hexanes (10:10:5) as a solvent system, 96.1% of the -^C
activity was associated with TNT. A second solvent system [benzene:hexanes:
pentane:acetone (50:40:10:3)] was found to be superior to the first system in
that it separated out a larger number of compounds. This chromatograph
indicated that 92% of the ^C was incorporated into TNT. Trace amounts of ^C-
labeled 2,2',6,6'-tetranitro-4,4'-azoxytoluene or closely related compounds
may have been present in the stock solution. The mono- or diamino derivatives of
TNT were not detected.
^•Analysis performed by the Soil Testing and Plant Analysis Laboratory, Virginia
Polytechnic Institute and State University.
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Table 1. Results of Thin Layer Chromatographic Analysis of ^C-TNT Stock
Benzene:Toluene:Hexanes (10:10:5)
Benzene rHexanes:Pentane:Ace tone
(50:40:10:3)
Rf
0.59
0.52
0.44
0.00
0.47
0.41
0.34
0.29
0.09
0.04
0.00
Probable
Compound (Rf)
TNT (0.52)
-
Tetra (0.39)
-
-
TNT (0.38)
-
Tetra (0.30)
-
-
_
DPM
132459
2370
1887
1184
303
77744
5722
438
190
247
352
Percent
of Total
96.1
1.7
1.4
0.9
0.3
92.0
6.3
0.5
0.2
0.3
0.4
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Uniformly ring labeled ^C-RDX was synthesized by Atlantic Research
Corporation. The source of ^C used to make RDX was ^C--f ormaldehyde purchased
from Pathfinder Laboratories. The method of synthesis is given in Appendix A.
The thin layer chromatograph of ^C RDX was developed in a 4:1
mixture of methylene chloride and acetonitrile. The radiochemical purity of RDX
was high, with the RDX containing 97.0% of the radioactivity. Additional
activity was located at the origin on the chromatograph and in an unidentified
spot with an Rf of 0.49. The results are summarized in Table 2.
C. Analytical Methodology
1. Development of Procedures to Extract TNT from Compost
a. Cold Acetone Extraction
Chopped alfalfa and horse feed material (50 g dry weight) were
spiked at 10,000 ppm TNT containing 0.25 Ci 14C-TNT and extracted 3X with 400
mL acetone followed by two x 400 mL benzene extractions.
Sample A - 41.7% recovery in acetone extract
4.1% recovery in benzene extract
Sample B - 42.0% recovery in acetone extract
3.9% recovery in benzene extract
b. Cold Acetone Extraction With Agitation
Seven week old material (50 g dry weight) was spiked at 10,000
ppn. TNT containing 0.24 yCi ^C-TNT and extracted with 400 mL acetone on a
shaking table for 30 minutes. The extraction was repeated twice for a total of
3 extractions. The compost was then extracted twice with 400 mL benzene for 30
minutes on a shaking table followed by one extraction with 400 mL distilled
water adjusted to a pH of approximately 3 (HC1) for 30 minutes on a shaking
table. An additional water extraction was performed with 400 mL distilled water
adjusted to a pH of approximately 11 (NaOH):
64.8% recovery in acetone
13.0% recovery in benzene extract
No significant recovery was obtained in acidic
or basic water extracts
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Table 2. Thin Layer Chromatographic Analysis of ^C-RDX Stock
Compound (Rf) DPM
Percent
of Total
Methylene chlorideracetonitrile (4:1)
0.72
0.49
0.00
RDX (0.74)
20168
426
158
97.0
2.0
0.8
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c. Warm Acetone Extraction
Composted material (50 g dry weight) was spiked at 10,000 ppm
TNT containing 0.24 yCi 14C-TNT and extracted with 400 mL acetone at 37°C with
agitation for 15 minutes. Two additional warm acetone extractions were
performed:
Sample A - 87.9% recovery
Sample B - 89.0% recovery
This procedure was used for preliminary TNT laboratory compost extractions.
d. Benzene/Methanol Extraction for TNT in Compost
One hundred and sixty mL of warm benzene/methanol (120:40)
were added to 20 g (dry weight) composted material. These samples were warmed
to 37°C in a water bath and agitated by shaking every 5 minutes for 30 minutes.
The extract was then filtered by vacuum through Whatman #2 filter paper. The
solids were re-extracted twice with 160 mL warm benzene (for a total of 3
extractions). Recovery of l^C from compost samples ranged from 97.9% to 94.3%
using this procedure.
2. Development of Procedures to Extract RDX from Compost
One hundred sixty mL of warm acetone were added to 20 g (dry)
weight) composted material. These samples were placed in a water bath to
maintain a temperature of 37°C. The samples were agitated at 5 .minute
intervals. After 30 minutes, the extract was filtered by vacuum through Whatman
#2 filter paper. The solids were extracted twice with 160 mL warm acetone (for
a total of 3 extractions). The extracts from the three extractions were pooled.
This extraction procedure resulted in recovery of 97.5% of the ^C-RDX spiked
into the composted material.
3. Quantitative Analysis of TNT
Composted material (50 g wet weight) is extracted with 160 mL
benzene: me thanol (75:25). Warm extractant, 160 mL is added to each jar
containing the compost material and the jars are placed in a 37°C waterbath.
Jars are agitated at 5 minute intervals. Jars are removed from the waterbath
after 30 minutes. The liquid extract from each jar is filtered through Whatman
#2 filterpaper into a glass flask. The filtrate is transferred to glass culture
tubes and diluted as necessary for analysis by GC.
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a. Instrumentation
Gas chromatograph - Hewlett-Packard 5880A with computer con-
troller and integrator, autoinjector and electron capture detector.
b. Parameters
Column - 1.52 OV17/1.952 OV210 on 80/100 Anakrom Q in a 2 mm
I.D., 0.125 in. O.D. by 6 ft. glass column.
Temperature: injection port - 210°C
oven - 180°C
detector - 300°C
Temperature Programming - isothermal
Carrier Gas - nitrogen at 28 cc/min.
Detector - electron capture
Injection Volume - 2 yL
Retention Time - 3.2 min.
c. Calculations
The concentration of explosive (ppb) in the sample is read
directly from the standard curve. The apparent concentration of explosive in
the compost is calculated from the formula given below:
Concentration (ppm) = ppb x 120 mL extract x 0.001 x reciprocal of extract dilut
g dry weight compost
4. Quantitative Analysis of RDX
Composted material (50 g wet weight) was weighed into jars and
extracted three times with acetone. Warm acetone, 160 mL, is added to each jar
containing the composted material and the jars are then placed in a 37°C water
bath. All jars are agitated at 0, 10 and 20 minutes. Jars are removed from the
water bath after 30 minutes. The liquid extract from each jar is filtered by
vacuum through two layers of filter paper in a Buchner funnel. Each filtrate is
collected in a 500 mL glass filter flasks. Following the third extraction, the
final volume of filtrate (composite of extracts 1, 2 and 3) is measured in
a 500 mL graduated cylinder. Aliquots of each filtrate are placed in glass
culture tubes for analysis by GC.
a. Calculations
The concentration of explosive (ppm) in the sample is read
directly from the standard curve. The apparent concentration of explosive in
the compost is calculated from the formula given below:
Concentration (ppm) = ppm x total extract volume
g dry weight cr-ipost
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b. Instrumentation
Gas chromatograph,- Hewlett-Packard 5880A with computer con-
troller and integrator; auto injector and electron capture detector.
c. Parameters
Column - 2 ft x 2 mm I.D., 10% SE30 on 80/100 Supelcoport.
Temperature - injection port - 210°C
oven - 160-210°C
detector - 330°C
Temperature Programming - 10°C/min.
Carrier Gas - nitrogen at 30 cc/min.
Detector - electron capture
Injection volume - 2 j/L
Retention Time - 0.36 min.
5. Liquid Scintillation Counting
The laboratory studies employed a l^C tracer to follow the degrada-
tion or transformation of TNT and RDX in compost. Quantification of l^C-
activity was accomplished with a Beckman LS-7500 liquid scintillation counter.
The counting window was set at 300 to 655. The lower limit of the window was set
to avoid chemical fluorescence. The automatic quench control was employed to
automatically adjust the window for quenched samples.
A standard quench correction curve was constructed from counting a
series of sealed quenched standards and a sealed unquenched standard. All
standards were counted twice until the 2 6 error reached 1%. All counts were
corrected for background using a sealed reference background. An H number for
each sample was determined using a ^'Cs external standard. The H number
measures the shift in the Compton distribution due to quench and is therefore an
accurate indicator of sample quench or counting efficiency. A plot of counting
efficiency versus H number could not be accurately represented by a single
linear or quadratic expression. However, the use of two quadratic equations for
two sections of the curve did provide an accurate means to represent the curve
mathematically. The point at which the two curves met was termed H0 and a
counting efficiency was assigned at this point which was in agreement with both
quadratic equations. The curve and its mathematic equivalent are presented in
Figure 1.
A model TI-59C Texas Instrument calculator was programmed to
correct counts per minute (CPM) for quench, background and dilution, concentra-
tion or subsampling and thus minimize computational errors.
10
-------
n
% Counting Efficiency of Quenched Standards
—i
o
00
o
o
o
OS
c
i-!
n>
O
(0
a
o
3"
O
0)
-------
6. ^C-Product identification and Quantification
Purity assays of l^C-labeled explosives and quantification of
products produced during the composting of l^C-explosives were accomplished
using thin layer chromatography (TLC). One or more l^C samples and appropriate
non-labeled standards were spotted in separate spots on a single TLC plate.
Chromatograph development was in a saturated atmosphere. The plates were then
allowed to dry and X-ray film was placed on the plate for a set period of time.
The developed X-ray film (autoradiograph) showed dark areas which corresponded
with the i^C-spots on tj,e TLC plate. Spots containing ^C were located and
mapped on the TLC plate with the autoradiograph. The unlabeled standards and
other fluorescent spots were located by exposing the TLC plates to shortwave
(253.7 nm) ultraviolet light. Identification of the l^C compounds was
accomplished by comparing their Rf values with that of known standards.
Quantification of the l^C activity in each spot was accomplished by scraping the
silica gel from the TLC plate directly into a scintillation vial, adding 10 mL
of counting cocktail and counting the vial.
The following standards were used in TLC analysis:
For TNT analysis: 2,4,6-trinitrotoluene (TNT)
2-amino-4,6-dinitrotoluene (2-amino-DNT)
4-amino-2,6-dinitrotoluene (4-amino-DNT)
2,6-diamino-4-nitrotoluene (2,6-diamino-NT)
2,2" ,6,6'-tetranitro-4,4'-azoxytoluene (tetra)
For RDX analysis: hexahydro-l,3,5-trinifro-l,3,5-triazine (RDX)
?• ^C-Detection Limit by TLC
An aliquot of the TNT solution at 1.97 x 107 DPM/mL was diluted with
acetone and a 100 fiL aliquot was counted. The sample contained 238.5 DPM.
Aliquots of this stock solution were spotted on duplicate TLC plates. Spots
contained approximately 30 DPM, 60 DPM, 90 DPM, 120 DPM, 190 DPM or 240 DPM. The
plates were dried, film was placed on the plates and exposed for 8 days or for
14 days.
After 8 days of exposure, the 30 DPM spot was not visible on the
autoradiograph. A faint spot was detected at 60 DPM and 90 DPM. Good spots were
detected at 120, 180 and 240 DPM. The spots were scraped and counted.
At the end of 14 days of exposure, faint spots were detected at 30
and 60 DPM. Good spots were visible at 90, 120, 180 and 240 DPM. The plates were
scraped and counted. Results are presented in Table 3.
12
-------
Table 3. Detection Limit Data for C on TLC Plates
8-day Exposure 14-day Exposure
Sample TLC PPM TLC PPM
*No
30 DPM
60 DPM
90 DPM
120 DPM
180 DPM
240 DPM
soot visible; not scraped
_*
62
92
112
189
263
25
59
97
121
199
266
Based on this detection limit study, any fraction of the sample
separated on the TLC plate containing as little as 30 DTM can be detected when
the film is exposed for 14 days. Exposure of the film for 8 days allows for
detection of fractions containing as little as 60 DPM.
8. Carbon and Residual - ^C Determinations
Prior to analysis, all samples were freeze-dried and ground to a
fine powder. Compost was ground in a ball mill. Activated carbon was crushed
with a mortar and pestle. Subsamples (0.08 to 1.1 g) of the material to be
analyzed were weighed into a ceramic combustion boat and covered with a 1:5 (by
volume) mixture of cupric oxide and aluminum oxide. Each sample was combusted at
850°C for 30 minutes in a Hoskins electric furnace. The furnace was continuously
flushed with 02- For total carbon analysis, the combustion gases were scrubbed
with 0.6 N NaOH to remove C02- A subsample of the NaOH trap was titrated to
determine the quantity of carbon released during combustion. Carbosorb
(Packard Instrument Co.) was used to absorb CC-2 released from the combustion of
materials containing l^C. The Carbosorb trap was mixed with an equal volume of
Permafluor (Packard Instrument Co.) in a scintillation vial and the l^C-
activity was determined by liquid scintillation counting.
9. Moisture Determinations
The moisture content of compost and compost ingredients was
determined by weighing 5 to 20 g of the material into preweighed beakers and
drying the samples at 80°C for 24 hours. After drying, the samples were cooled
in .a desiccator before they were reweighed. The moisture was calculated as the
weight loss during drying. The results are reported as percent moisture on a wet
weight basis. A minimum of three subsamples were dried for each moisture
determination and the average percent moisture value was used.
13
-------
10. pH Determinations
The pH of individual composts was determined on a distilled water-
compost slurry. Ten grams (wet wgt.) of compost were mixed with 30 mL of
distilled water and allowed to sit for 45 minutes. The slurry was then stirred
and the pH read immediately using standard calomel and glass electrodes with a
pH meter. The average solid to liquid ratio of the slurry was 9:1 due to the
moisture content of the compost.
11. Nitrogen Analysis
The total Kjeldahl nitrogen content of compost was determined using
the Semimicro-Kjeldahl method described in Methods of Soil Analysis ( 1965).
Prior to analysis, all samples were freeze-dried and ground to a fine powder.
12. Oxygen and Carbon Dioxide Determinations
The Q£ and C02 concentrations in the compost atmospheres were
determined by gas chromatography analysis. A Varian 3700 GC was used with a 6
ft. CTR column (Alltech). Conditions used are given below:
Temperature - injection port - 200°C
oven - 65°C
detector - 260°C
Temperature Programming - isothermal
Carrier Gas - helium at 50 cc/min
Detector - thermal conductivity
Injection Volume - 80 ^L
14
-------
III. PRELIMINARY TNT LABORATORY COMPOST
A. Experimental Procedures
Three preliminary bench-scale composts were initiated in the laboratory
to monitor breakdown of ^C-TNT by composting and to establish solvent systems
for separation of l^C-containing compounds from each other and from other
compost products.
The individual components of the compost were dried to determine the wet
weight of each component required to prepare a specific (dry weight) compost
mixture. Four alfalfa hay samples (10 g), four Purina Sweetena horsefeed
samples (20 g) and four aliquots of the seed compost were used for the moisture
determinations. The moisture contents of the hay, horsefeed and seed compost
were 8.1%, 9.3% and 43.1%, respectively.
Using the predetermined moisture content of hay and horse feed, three
composts were prepared as follows. Three 21 g (dry weight) hay samples were
weighed into each of three one quart jars (0.95 L) and 67.0 mL of water were
added to each jar. The jars were stoppered and allowed to stand for one hour to
allow the hay to absorb the water. Horse feed (21 g dry weight) was added to each
jar, the contents were mixed and the jars stoppered and allowed to equilibrate
overnight.
Samples of Lakeland soil were weighed (14.5 g) into each of three
beakers. Approximately 1 yCi of ^C-TNT in acetone (0.22 raL) was added to the
sand in each of two beakers. Production grade TNT dissolved in acetone (1.76 mL
containing 0.4967 g TNT) was also added to the sand in each of the three beakers.
The beakers were covered and placed in a hood in the dark to evaporate the
acetone.
On day two, 3 g (dry weight) of the seed compost were added to each of the
compost jars containing hay and horsefeed. The TNT contaminated soil (dry) from
one beaker was scraped into one compost jar with a rubber policeman. The second
and third beakers were also scraped into individual compost jars. An additional
1.7 mL of water were added to each jar to bring the total water content of the
compost flasks to 75.0 mL (56% moisture content). All components (hay,
horsefeed, seed compost, soil and water) were well mixed.
A ring of plastic tubing with holes drilled at 1/4 inch intervals was
located beneath the compost in each jar. The ring was connected to a glass tube
extending through the stopper to provide aeration for the experimental
composts. A thermocouple for monitoring of compost temperature was placed in
the center of each compost. As shown in Figures 2 and 3, each jar was securely
stoppered, all tubing attached to the proper trap or vacuum system and the
vacuum was applied to pull air through the compost materials. Air was drawn
successively through a NaOH and a H20 trap to remove C02 and humidify the air
before entering the compost. Gases exiting the compost were passed through
H2S04 (36N), NaOH (5N) and activated carbon traps to retain volatile
materials resulting from the breakdown of
15
-------
cr-
Thermocouple and
Thermistor Meter
Activated
Carbon Trap
To
Vacuum
Perforated
Tubing
I
K
Drying
Tube
Need 11*
Valve
Ik-.id
Tr.ip
Trap
Me.ul
Tr.ip
N ill III
Trap
Figure 2. Schematic of ^C-Bench-Scale Composting Apparatus
-------
Figure 3. Picture of a Bench Scale Composting Apparatus
-------
An unlabeled compost (control - contained TNT but no ^C-TNT) was set-up
in the same manner. The aeration system for the unlabeled compost was
simplified as illustrated in Figure 4.
B. Results of Preliminary TNT Composting Study
1. Routine Monitoring of Composts
The temperature of each compost and the air temperature of the
incubator were recorded once daily. The results are compiled in Table 4.
Generally there was little difference between the compost and incubator
temperatures.
Samples of the compost atmosphere were removed via the cannula
(Figure 4) from each control compost and analyzed by gas chromatography on a
weekly basis. Oxygen levels in the compost atmosphere were determined to lie
between 4 and 7% at all times sampled during the three week incubation.
The NaOH traps were changed every seven days, or more often if the
traps neared saturation with C(>2. A one mL aliquot of the trap was counted for
60 minutes to determine l^C activity. The results in Table 5 show that ^C
recovery from the NaOH traps was very low. Average recovery over the three-week
composting period totaled 0.08% of the l^C originally added to the compost.
The H2S04 traps were sampled after 6, 14 and 21 days of com-
posting. One mL of the trap was removed at each sampling and counted for 60
minutes. No significant ^C-activity was detected in the samples. The results
are given in Table 6.
2. Extraction of Three-Week Preliminary Laboratory 1^C-TNT Composts
The two composts containing l^C-TNT were extracted three times with
400 mL warm (37°C) acetone. The 400 mL aliquot of acetone was added to the
compost in the jar which was placed in a water bath at 37°C. The jar was agitated
at 5 minute intervals and removed from the" water bath at the end of 15 minutes.
The extract was vacuum filtered (Whatman #2 filter paper). The procedure was
repeated two additional times and the extracts were combined and brought to a
final volume of 1125 mL. Aliquots (1 mL and 200 0L) of the 1125 mL combined
extracts were counted. In Sample A, 50.8% of the ^C was recovered and 62.3% of
the l^C was recovered in Sample B.
3. Analysis of Preliminary Compost Extracts
Compost extracts were stored in the dark to prevent photoreduction
of TNT. However, after several days storage in the dark at room temperature, all
18
-------
Stoppered
Cannula
Air
Thermocouple and
Thermistor Meter
To Vacuum
Perforated
Tubing
Compos t
Figure A. Schematic of Unlabeled (Control) Bench-Scale
Composting Apparatus
-------
Table 4. Daily Temperature Readings for the Preliminary Composts
14C-Labeled
TNT Compost A
14C-Labeled
TNT Compost B
Unlabeled
TNT Compost (control)
Incubator
9/13/81
9/14/81
9/15/81
9/16/81
9/17/81
9/18/81
9/21/81
9/22/81
9/23/81
9/24/81
9/25/81
9/28/81
9/29/81
9/30/81
10/01/81
10/02/81
54.0
54.0
52.0
53.0
53.0
53.5
53.0
54.0
53.0
53.0
54.0
52.0
52.0
52.5
53.5
53.0
53.0
53.0
53.0
53.0
52.0
53.0
53.0
54.0
53.0
53.0
54.0
51.5
52.0
52.5
53.5
53.0
53.0
53.0
53.0
53.0
53.0
53.0
53.0
54.0
53.0
53.0
54.0
52.0
52.0
52.5
53.5
53.0
52
52
54
54
53
54
54
55
55
55
55
55
54
54
57
54
20
-------
Table 5. ^C-Activity in NaOH Traps from the Preliminary Composts
Sample
6 day Compost
Compost
14 day Compost
Compost
20 day Compost
Compost
21 day Compost
Compost
A
B
A
B
A
B*
A
B
Total DPM
334
272
316
768
304
927
185
106
% 14C
Recovered
0.02
0.01
0.02
0.04
0.01
0.04
0.01
0.01
*Traps saturated.
Total C recovery as CC>2 A - 0.06%
B - 0.10%
21
-------
Table 6. C Recovery in H2S04 Traps from the Preliminary Composts
_ Sample _ Total PPM __ Recovered
6 day Compocst A 0 0.00
Compost B 0 0.00
14 day Compost A 0 0.00
Compost B 0 0.00
21 day Compost A 20 0.00
Compost B 67 0.00
22
-------
extracts turned a dark red color indicating that TNT was reduced. The three-
week acetone compost extracts were evaporated to dryness with a rotary vacuum
evaporator. The dried extracts were redissolved in benzene followed by
sequential, acetone and methanol washings. The benzene contained 9.1.6% of the
radioactivity contained in the original acetone extract. The combined recovery
of radioactivity in acetone and methanol was 2.6% of the total radioactivity in
the original acetone extract. The extract dissolved in benzene was analyzed by
TLC using eight solvent systems (see Table 7). Autoradiographs indicated that
solvent systems #1, 2 and 4 gave the best separation of the extract components.
The three radioactive spots present on each chromatograph were tentatively
identified as TNT and the 2-amino and 4-amino reduction products of TNT. No
further analysis of the extracts was attempted because of the obvious problem
with TNT reduction in the extracts.
4. Conclusions Based on Preliminary TNT Compost Experiment
The initiation and incubation of the preliminary composts ident-
ified a number of minor problems which were corrected with only slight
modification in the proposed set-up. The major problem identified during the
preliminary compost period was that acetone extracts of the TNT compost were not
stable even when all possible precautions were taken, i.e. removal from light,
storage at low temperatures and limited storage times. An extraction procedure
using benzene .'methanol was developed for use in the subsequent laboratory and
greenhouse compost experiments to avoid the problem of instability.
Three of eight solvent systems investigated for TLC separation of
TNT extract components yielded good separation of TNT from the amino products
formed by reduction of TNT. Solvent system #8 was found to separate TNT from
2,2',6',6'-tetranitro-4,4'-azoxytoluene. By combining solvent systems #8 and
#2 it a two dimensional TLC development, TNT and all its transformation products
for which standards were available could be separated.
Temperatures in ^C-labeled and unlabeled TNT compost jars ware
approximately the same, ranging from 51.5 to 54°C. Based on the oxygen analysis
of the compost atmosphere, the compost was aerobic at all times. Little of the
l^C introduced into the compost as TNT was recovered in the sodium hydroxide
traps, indicating that ring cleavage probably did not occur. No significant
14-C-activity was found in the acid traps or in the carbon traps, indicating that
volatile amines and volatile aromatic compounds were not produced in detectable
quantities during laboratory composting. Based on recovery of l^C in three-week
compost extracts, 40-50% of the 14C introduced into the compost was no longer
solvent extractable. TLC analysis of the compost extract gave three radioactive
spots. The majority of the radioactivity on each plate (88.3 and 89.2%) was
contained in a spot with an Rf corresponding to the TNT standard. A small
percentage of the 14C (3 to 8%) was tentatively identified as the 2-amino and 4-
amino-DNT reduction products. Polar products at the origin of the plate
accounted for 3 to 4% of the ^C-activity.
23
-------
Table 7. TLC Solvent Systems Evaluated for TNT Analysis*
1. Toluene:benzene:hexanes (10:10:5)
2. Benzene:hexanes:pentane:acetone (50:40:10:3)
3. Hexanes:acetone (3:2)
4. Chloroform
5. Chloroform:methanol:acetic acid (8:20:1)
6. Chloroform:ethyl acetate (3:2)
7. Benzene:ethyl acetate:acetic acid (15:10:1)
8. Petroleum ether:ethyl acetate:hexanes (160:80:25)
*A11 systems on a volume to volume basis.
24
-------
IV. LABORATORY COMPOSTING OF TNT AND RDX
A. Compost Set-Up
Composts containing approximately 1% TNT or RDX were set-up essentially
as were the composts in the preliminary study. Nine composts for each explosive
were prepared to be sampled in triplicate at 0, 3 and 6 weeks of composting. Each
of these composts was dosed with one l^C-labeled explosive (TNT or RDX) to
monitor the degradation of TNT and RDX. Five additional control composts for
each explosive were set up to monitor the pH, moisture, ©2, carbon and nitrogen
content of the composts. One of these control composts was sacrificed (the
entire compost sample was extracted) at time zero. Two of the control composts
for each explosive were sacrificed after 3 and 6 weeks of composting. A summary
of the laboratory composting system is presented in Table 8.
1. Soil Spikes
TNT contaminated soil was prepared by adding 2.1 mL of ace-
tone containing 0.4969 g of production grade TNT and 0.22 mL of acetone
containing 1.06 yCi of ^C-labeled TNT to 10 g of air dried soil in a 50 mL
beaker. RDX soil spikes were made by adding 13.1 mL of acetone containing
0.6144 g of production grade RDX and 0.85 mL of acetone containing 0.72 /*Ci of
l^C-labeled RDX to 10 g of soil. Control soils were spiked with the same
quantities of production grade explosive but no l^C-labeled material was added.
One soil sample was prepared for each compost. The beakers containing the dosed
soil were wrapped in aluminum foil and allowed to dry overnight in the dark, in
a hood at room temperature.
2. Laboratory Composts
The moisture contents of the hay, horsefeed and seed compost used
were determined by drying triplicate samples for 24 hours at 80°C. The weights
of these materials and the water added to the compost were adjusted for the
moisture levels of the starting material. Hay (18.5 g dry weight) was weighed
into quart size glass jars and 56.4 mL of distilled water were added to each jar.
Horse feed (18.5 dry weight) was added to each jar; the contents were well mixed
and the jars stoppered. Seed compost (3 g dry weight) was added to each of the
jars containing hay and horsefeed. The soil containing TNT (or RDX) from one
beaker was scraped into one compost jar with a rubber policeman. The beaker was
rinsed twice with approximately 1 mL acetone. The acetone rinses were added to
the compost jars. Each beaker was treated in the same manner. An
additional 11 mL of water were added to each jar to bring the total water content
of the compost jars to 75 mL (60% moisture content). All components (hay,
horsefeed, seed compost, soil, water) were thoroughly mixed with a glass
stirring rod.
25
-------
Table 8. Summary of Laboratory Compost Systems
1) Compost - 50 g (dry weight) hay and horsefeed compost; initial moisture
content adjusted to 60% (wet weight basis).
a. dosed with TNT (1%), included uniformly ring labeled ^C-TNT
at a specific activity of 2.13 yCi/g or
b. dosed with RDX (1%), included uniformly labeled 14C-RDX at
a specific activity of 1.17 pCi/g or
c. control composts contained 1% TNT or RDX, no ^C-labeled
explosives added.
2) Composting conditions:
a. incubated at 55°C
b. continuously aerated with humidified and warmed CC>2 free air
c. off-gases scrubbed through H2S04, NaOH and activated carbon
traps
3) Sampling procedures:
a. three replicate l^C composts sacrificed at 0, 3 and 6 weeks
of composting to monitor TNT or RDX disappearance
b. two replicate control composts sacrificed at 3 and 6 weeks
of composting to monitor pH, moisture level, carbon and
nitrogen contents
c. H2S04 and NaOH traps changed as needed to prevent trap
saturation
d. temperature monitored daily
e. Q£ and C02 levels in control composts monitored weekly
4) Analysis:
a. RDX, TNT, TNT transformation products quantified by TLC and
liquid scintillation counting (LSC) of compost extracts
b. residual ^C in the compost determined by combustion followed
by LSC
c. H2S04 and NaOH traps assayed for ^C by LSC
d. C retained in activated carbon quantified by combustion
and LSC
e. 02 and C02 levels determined by GC.
26
-------
The beakers that contained the dosed soils were washed with an
additional 3 mL of acetone to remove residual ^C. An average of 4972 DPM of TNT
and an average of 8939 DPM of RDX remained in the acetone wash of the beakers.
The quantities of explosives and l^C-labeled material added to each flask are
summarized in Table 9.
The composts to be sacrificed at time zero were randomly selected.
The l^C composts were extracted by appropriate methods immediately. The control
composts were freeze dried and stored until carbon and nitrogen analyses were
performed.
The remaining composts were connected to an appropriate aeration
system (Figures 3 and 4) as described in the Preliminary TNT Laboratory Compost
section and incubated at 55°C. The aeration system removed C02 from the air,
saturated it with water, then drew the air through the compost. Air entering
this system was from inside an incubator (55°C) and therefore did not cool the
compost. Humidification of the air pulled through the compost maintained an
acceptable moisture content in the compost. Off-gases from the compost were
scrubbed through concentrated H2S04 to trap volatile amines (possible meta-
bolites from TNT degradation), through 5 N NaOH to trap 1^C02, through a
drying tube (CaS04) to remove excess moisture and through activated carbon
to remove volatile aromatics.
B. Results of Laboratory Compost Studies
1. Routine Monitoring of Composts
The procedures used for monitoring the laboratory composts are
outlined in Figure 5 and described in detail in the following paragraphs. The
temperature of each experimental compost was monitored and recorded daily. In
general, the compost temperatures ranged from 51 to 55°C as did the temperature
of the incubator. Compost temperatures during the second three-week incubation
were higher with some readings as high as 59°C, a reading at least 2°C higher
than the temperature in the incubator. The daily temperature readings are
compiled in Appendix D.
14-C02 resulting from TNT and RDX breakdown in the compost was
trapped by bubbling all off-gases through NaOH. The traps were changed
frequently (every 5 days or less). The cumulative evolution of 1^C02 during RDX
composting is illustrated in Figure 6. Each point on the curve represents an
average of three replications. The recovery of ^C activity as ^C02 from the
TNT composts was very low. Recoveries ranged from 0.2 to 0.6% of the *^C added
to the compost. Average recoveries from the 3 and 6 week composts were 0.2 and
0.5%, respectively.
27
-------
Table 9. Quantity of RDX and TNT Added to Individual Laboratory Composts
Compound
14C-TNT
Production TNT
!4c-RDX
Production RDX
Specific
Activity (MCi/mg)
25.59
312.50
p Curies
Added
1.0603
0.7200
Explosive
Added (mg)
0.0414
0.4959
0.0023
0.6110
Concentration of
Explosive in Compost*
1.07%
1.45%
00
"'Corrected for explosive not transferred from beaker into the compost.
-------
Freeze Dry & Grind
Combus tion
14
14
C Activity of
C0? Released
14
C Compost
Volatile
Losses
S
\
H2S°4
NaOH
X
C Activity
Solvent Extraction
C Activity/Spot
by LSC
Freeze Dry & Grind
Gas Analysis for 0 & CC>2
Moisture Determination
Combustion for Total Carbon
Total Kjeldahl Nitrogen
Figure 5. Schematic for Monitoring Laboratory Composts
29
-------
80
70
CO
o
O
O
w
(J
30
20
10
0
20
Time (days)
30
40
Figure 6. Cumulative Percent ^C Recovered as *^C02 from
^C-labeled RDX in Compost
-------
Recovery of C from the H2S04 traps was low for both TNT and RDX
composts. Average cumulative recoveries after 3 and 6 weeks of composting are
given in Table 10.
Table 10. Average Cumulative Recoveries of l^C-activity from
H2S04 Traps
Cumulative
Explosive _ Composting (week) _ Recovery (%)
TNT
RDX
3
6
3
6
0.0
0.2
0.3
0.7
The activated carbon traps were sampled at the completion of the
experiment. The carbon was thoroughly mixed and a subsample was removed and
crushed to a fine powder with a mortar and pestle. Two subsamples of the crushed
carbon were combusted to release the ^C for liquid scintillation counting. The
combustion method was described in Section IIC-8. The recovery of ^C for both
RDX and TNT from the activated carbon trap was essentially zero (background
level).
The jars containing the control composts were fitted with a stop-
per containing a septum through which samples of the compost atmosphere could be
withdrawn. Once a week duplicate samples were taken from each control compost
for GC analysis to determine the oxygen (02) and carbon dioxide (CC>2) levels in
the compost. The GC conditions and column used are described in Section IIC-12.
Both the 02 and C<">2 levels were highly variable among replicate samples (See
Table 11). The ©2 levels and C02 were inversely related. The Q£ content was
sufficiently high in all samples to avoid anaerobic conditions.
2. Analysis of Control Compost
For week 0, one TNT and one RDX control compost were sacrificed for
analysis. At weeks 3 and 6, analyses were performed on duplicate control
composts of each exlosive. The composts to be sacrificed were randomly
selected. Two subsamples of each compost were removed. One was dried at 80°C for
24 hours to determine the moisture content. The second subsample was combined
with distilled water (approximately a 1:9 (w/v) solid to water combination),
allowed to stand for 45 minutes, and then the pH of this slurry was measured
using standard calomel and glass electrodes. The remaining compost was freeze-
dried and then ground to a fine powder in a ball mill Two subsamples of the
powdered compost were combusted to determine total carbon, and one or two
subsamples were analyzed for Kjeldahl nitrogen (see Section IIC-11 for
methods). Results are summarized in Table 12.
31
-------
U)
to
Table 11. Oxygen and Carbon Dioxide Levels in Control Compost Atmospheres
TNT RDX
02 (%) C02 (%) 02 (%) C02
Composting (days)
8
15
22
27
40
* X
S
X*
15.9
21.8
17.2
18.4
8.9
Arithmetic
8 X S X
5.3 11.4 7.8 16.0
1.9 4.0 2.6 19.7
11.1 10.4 14.7 16.1
93.9 4.2 6.5 21." 9
10.0 12.5 12.9 17.3
mean
S
5.8
5.3
14.1
1.1
1.5
X S
8.8 5.7
6.0 6.5
14 . 0 14 . 6
4.2 2.7
4.2 3.3
Standard deviation
-------
Table 12. Analysis of Control Composts for Laboratory Study
LO
U>
Length of
Sample Composting (week)
TNT 1
2
3
4
5
RDX 1
2
3
4
5
0
3
3
6
6
0
3
3
6
6
PH
5.9
8.1
6.0
8.0
4.7
5.9
8.3
4.8
8.5
8.8
Percent
Moisture
60.0
58.8
59.7
61.9
56.3
60.0
66.3
53.1
64.5
70.1
Total
Carbon
32.8
29.8
33.7
26.8
32.9
31.0
25.5
32.3
22.8
22.9
Total
Nitrogen
2.1
2.0
1.9
2.0
1.6
2.1
1.9
1.7
2.0
1.8
-------
3. Analysis of ^C-labeled Composts
At 0, 3 and 6 weeks of composting, three jars containing ^C-labeled
TNT and 3 jars containing l^C-labeled RDX compost were selected at random to be
sacrificed. The entire contents of each jar were extracted by the method
described in Section II for extraction of TNT or RDX from compost. An aliquot
of the extract (0.5 mL or 1 mL) was counted for ^C-activity by liquid
scintillation counting to determine what percentage of the total ^C-radio-
activity added to the compost was recovered in the extract. The remainder of the
extract was stored in sealed glass containers at room temperature in the dark
until rotary vacuum evaporation was carried out in preparation for TLC analysis.
The results are summarized in Tables 13 and 14. RDX and TNT composts
demonstrated a dramatic decrease in extractable ^C-activity as the length of
compos t ing increased.
Following extraction,, the compost solids were freeze-dried, then
weighed and powdered by grinding in a ball mill for two or more hours. Duplicate
subsamples were combusted to determine the residual l^C-activity in the
compost. The results are given in Tables 13 and 14. The total residue activity
was corrected for weight loss during composting.
The compost extracts were concentrated by rotary vacuum evaporation
to dryness. The dried extract was washed out of the drying flask with 8 to 12
mL of solvent (benzene for TNT, acetone for RDX). The solvent containing
explosive was then reduced in volume to approximately 0.5 mL by blowing N£
across the sample. A suitable aliquot (5-20;iL) of this concentrated extract was
analyzed by TLC. The TLC procedures are described in Section IIC-6. The TNT
analyses performed use two-dimensional TLC plates. The solvent systems used
were petroleum etherrethyl acetate:hexanes in ratios of 160:80:25 (solvent
system #8) and benzene:hexanes:pentane:acetone combined in ratios of 50:40:10:3
(solvent system #2). The separation of TNT and its transformation products in
this system is illustrated in Figure 8. Solvent system #8 travels from left to
right across the plate separating the mono- and diamino derivatives of TNT.
Solvent system #2 moves from the bottom to the top of the plate separating TNT
from the tetranitroazoxy derivatives. The results for each individual extract
are given in Table 15. Only TNT was detected at time zero. After three weeks
of composting 45 to 49% of the ^C initially added to the compost was recovered
as TNT and a small percentage of ^C was found at the origin. After six weeks
of composting, the TNT levels were further reduced (0 to 37% of 14C recovered as
TNT). Small quantities of the TNT transformation products were found and between
0.9 and 2.0% of the total ^C activity did not move from the origin on the TLC.
In one replicate, when no TNT was recovered, two new unidentified radioactive
spots were seen on the TLC. The 14-activity of these spots was low, with less
than 0.5% of the total activity found in either spot.
34
-------
Table 13. Summary of 1/fC Recovered from ^C-TNT Laboratory Composts
% Recovery of
Length of
Composting
0 weeks
3 weeks
6 weeks
14C02
0.0
0.2
0.5
1Total ^C-activity £n
Table
Length of
Composting
0 weeks
3 weeks
6 weeks
14 . Summary
I4co2
0.0
19.6
55.8
H2S04
Trap
0.0
0.0
0.0
compost
of Me
H2S04
Trap
0.0
0.3
0.7
Carbon
Trap
0.0
6.0
0.0
Solvent
Extract
93.5
47.8
19.3
extraction present as
Recovered
%
Carbon
Trap
0.0
0.0
0.0
from 14C-RDX
Recovery of
Solvent
Extract1
112.3
68.9
21.6
Residual-^C
1.7
37.8
66.5
14c-TNT and other
Total
95.2
85.8
86.3
l^C-compounds.
Laboratory Composts
14C
Residual-14C
6.1
13.5
16.1
Total
118.4
102.3
94.2
*Total l^C-activity £n compost extract present as
-------
Solvent
Solvent System
#8
O 2-amino DNT
O 4-amino DNT
2,6-Diamino NT
TNT and Tetra
TNT
4-amino DNT
ino DNT
NT ?
Solvent System
#2
TNT
0 Tetra
9
2-amino DNT and 4-amino DN"
2,6~Diamino NT
Figure 7. Separation of ^C-TNT by TLC
36
-------
Table 15. C Recovery from TNT Laboratory Compost
Extracts
u>
Length of
Composting
0 weeks
3 weeks
6 we e k s
Replicate
A
B
C
A
B
C
A
B
C
TNT
89.8
88.8
101.8
44.5
48.9
46.5
N.D.
37.0
12.9
7o or iotai "i;
A* B C HE
1.5
1.0
0.9
0.1 1.0 0 . 6**
1.1 2.0
0.6 1.1 0.8 0.9
yf
A - 2-amino-2,4-dinitrotoluene
B - 4-amino-2,6-dinitrotoluene
C - this was not a discrete spot on any chromatograph but an area .that would contain 2,6-diamino-
4-nitrotoluene if it was present
D - origin
E - other unidentified ^C-compounds
•-'•-^Present in two spots
N.D. - Not Detected
-------
A second set of extractions was performed to ensure that the amino
transformation products of TNT would be detected if they existed. The "C"
replicate of the 6-week old compost was chosen as a test sample because it was
the only compost where detectable quantities of the 2-amino, 4-amino, and 2,6-
diamino derivatives of TNT were tentatively identified in the benzene extract.
Aliquots of the compost, after being freeze-dried and ground were extracted with
acidified methanol (pH 4.5) or with basic methanol (pH 11.5-12) to extract any
amino derivatives in the TNT compost which had not been removed by the benzene
extraction. One gram of dry powdered compost ("C") was extracted with 5 mL of
acidic or basic extracting solution, centrifuged and an aliquot of the extract
counted for radioactivity. Results of these extractions are given in Table
16.
Table 16. 14C in Acid and Basic Methanol Extracts from
14c TNT Laboratory Composts
Extract
Acid
Bas-ic
Vol.
0.
1.
0.
1.
Counted
5 ml
0
5
0
DPM (total)
131699
133023
120520
122369
I ^C
5.6
5.7
- 5.1
5.2
The remainder of each extract was concentrated by evaporation with nitrogen and
analyzed by TLC using solvent system #8. The ^-^C-activity on the TLC plate was
relatively low. Therefore, spots were visualized with UV light and the regions
between spots were divided in segments. Each spot and segment was scraped from
the plate and assayed for l^C-activity. As shown in Figure 8, three spots
were visualized with UV in the acid extract and two spots in tne basic extract.
Fraction 11 (acid) and 9 (base) corresponding to TNT and tetra and fraction 1
from each extract (origin) were the only areas giving counts which were
significantly above background. No 2,6-diaminonitrotoluene, 2-amino or 4-amino-
DNT were found in these extracts.
The solvent system used for TLC analysis of the ^^C-RDX extracts was
cyclohexanone. Chromatographs for individual compost extracts showed that the
only l^C-labeled compound present in the extracts from sampling times zero, 3
weeks, and 6 weeks was ^C-RDX. The three-week compost extract contained 68.9%
of the ^C-added to the compost whereas composting for six weeks resulted in an
average recovery of 21.6% of the l^C-RDX in the compost extract. Evolution of
during six weeks of composting was significant, and ^C-recoveries as
greater than 67% in individual compost replicates were observed.
38
-------
TNT and
Tetra
2-amino
-
a
o
a"
0)
CT
3-
01
3
h- •
i
r
[
fl
f
k
\
_ tf*.
r
L
\
3
h
^
-
L
12
n >
11 n
rr
0
. 10 >
0 °
9 H-
8 2
7 £
6 I
Q
5 "
4
3
2
1
\
/ ^
^-•f
i
/ i
U
10
9
8
7
6
5
4
3
2
1
Solvent System 1/8
- ammo
2,6- C
diamino
Acid Extract
Basic Extract
TLC ID
DPM*
Compound
DPM*
Compound
1
2
3
4
5
6
7
8
9
10
11
12
27.0
6.3
5.0
3.6
5.2
2.4
3.2
2.1
2.9
11.3
26.1
4.9
origin
2,6-diamino
2-amino
4-amino
TNT & Tetra**
42.3
4.4
3.6
5.0
1.5
2.7
1.7
3.7
33.1
2.1
origin
2,6-d iamino
2-amino
4-amino
TNT & Tetra
DPM corrected for quench and background
2,2',6,6'-tetranitro-4,4'-azoxytoluene
Figure 8. TLC Analysis of Acidic and Basic Extracts of
Laboratory Compost
39
-------
4. Statistical Analyses of Data from Laboratory Composts
Data obtained from composting of RDX and TNT in the laboratory were
statistically analyzed using a one-way analysis of variance. This test compares
the variance attributed to random variation in the total population being
observed to the average variance resulting from treatments being applied to the
population. The ratio of the treatment variance to the sample population
variance (error or replication variance) is termed the F value. If this ratio
equals one, the treatment variance equals the population variance; thus the
treatment has no affect on the population. As the F ratio increases above the
value of one, the probability that the treatment has altered the population
increases. Probabilities associated with F ratios for varying sample sizes are
commonly available in most statistical tables.
In the present situation, the treatment is length of time composted.
The ANOVA tests to see if the parameters measured (such as TNT concentration)
have been significantly changed by 3 or 6 weeks of composting. The ANOVA tables
(Tables 17 and 18) present the degrees of freedom and the sums of squares. These
values are used to calculate the mean squares which are equivalent to variances.
The probability for the F ratio is the probability that treatment differences are
not real.
A requirement for using ANOVA is that the data possess homogeneity
of variance. A portion of the data for both RDX and TNT lacked homogeneity of
variance at the 5% level of probability according the Cochran's test (Chemical
Rubber Company Handbook, 1968). Several transformations were used to equalize
variances. However, variances varied independently of means and no transfor-
mation corrected the lack of homogeneity for all data. The square root
transformation (x + 1/2) corrected the non-homogeneity of variance for all RDX
data but not for TNT data. Analysis of variance was performed on both RDX and TNT
results using non-transformed data, as well as using data with the square root
transformation. An additional test to examine the equality of means when the
variances are heterogeneous was used to analyze TNT data (Sokal and Rohlf, 1969).
With one exception (^C-recovered from the ^804 during RDX composting) F-ratios
were highly significant with predicted probabilities of less than 0.01. The
probabilities predicted from the F-ratios of these analyses were of the same
order of magnitude regardless of the transformation or type of test. These
results indicate that the lack of homogeneity of variance did not appreciably
alter the results of the analysis of variance. Therefore, all analyses were
performed on non-transformed data. A one-way analysis of variance was used to
test each parameter (i.e. ^^C02, solvent extract, etc.) separately for TNT and
RDX. The recovery of TNT in the solvent extract was also tested. The ANOVA1 s for
TNT and RDX are shown in Tables 17 and 18, respectively. When significant
differences were indicated by the analysis of variance, the Student-Newman-Kuel
Multiple Range Test was used to separate means. All testing was done at the 5%
level of significance.
Results of the Student-Newman-Kuel Multiple Range Test showed that
the 1^C02 recovered from the TNT laboratory composts at time zero was not
significantly different from that recovered by 3 weeks; however,
40
Use or disclosure of proprietary data is subject to the restriction on the Title page of this document.
-------
Table 17. Analysis of Variance Tables for the TNT Laboratory Composts
Parameter
Uco2
Solvent Extract
Residual 14C
TNT in the Solvent
extract
Source of
Error
Time
Error
Total
Time
Error
Total
Time
Error
Total
Time
Error
Total
Degrees of
Freedom
2
6
8
2
6
8
2
6
8
2
6
8
Sums of
Squares
0.4289
0.09333
0.5222
8400.7
866.7
9267.4
6318.7
169.5
6488.2
9005.0
819.1
9824.0
Mean F
Squares Ratio
0.2145 13.7857
0.01556
4200.4 29.0791
144.5
3159.4 111.8535
28.3
4502.5 32.9831
136.5
Probability
0.0057
0.0008
< 0.0001
0.0006
-------
Table 18. Analysis of Variance Tables for the RDX Laboratory Composts
Parameter
14C02
H2SO^ Trap
Residual 14C
Solvent Extract
Source of
Error
Time
Error
Total
Time
Error
Total
Time
Error
Total
Time
Error
Total
Degrees of
Freedom
2
6
8
2
6
8
2
6
8
2
6
8
Sums of
Squares
4808.2
417.2
5225.4
0.7356
0.2467
0.9822
159.8
28.1
187.9
12347.3
428jl
12775.4
Mean
Squares
2404 . 1
69.5
0.3678
0.0411
79.9
4.68
6173.6
71.4
F
Ratio Probability
34.5751 0.0005
8.9459 0.0158
17.0779 0.0033
86.5266 <0.0001
i
-------
recovered by 6 weeks was significantly different from both the 0 week and the 3-
week recoveries. 1^C02 recovered from the RDX laboratory composts at time zero,
3 weeks and 6 weeks were significantly different from each other. Analysis of
the l^C-recovery frOm solvent extracts of the TNT and RDX composts showed that
recoveries at each of the sampling periods were significantly different from
each other. Residual l^C £n the TNT composts was significantly different at
each sampling period. Residual l^C in the RDX composts at time zero was signifi-
cantly different from the residual carbon recovered at 3 weeks and 6 weeks;
however, the 3 week and 6 week recoveries were not significantly different from
each other. Recovery of ^C from the acid traps of the RDX composts showed that
the 6 week recovery was significantly different from the 0 and 3 week
recoveries; however, ^C-recoveries from the acid traps at 0 and 3 weeks were
not significantly different from each other.
C. Discussion and Conclusions Based on Laboratory Composting Data
Composting appeared to be an effective method of reducing TNT concentra-
tions without the formation of the undesirable transformation products that are
normally associated with TNT alteration in the environment or in biological
systems. As the composting time increased, TNT levels in the composts were
rapidly reduced as indicated by the recovery of ^C-TNT in the solvent extracts
(see Table 19). The solvent extractable TNT was reduced by half after three
weeks of composting and after six weeks of composting less than 17% of the TNT
was recovered on the average. The extract from one replicate of the six week
compost did not contain detectable levels of TNT (less than 0.01%). The
reduction in TNT was paralleled by a reduction in solvent extractable ^C and an
increase in the residual l^C activity (Table 13). Degradation or transformation
of TNT apparently resulted in the formation of products which are insoluble in
benzene and/or are very strongly sorbed to the compost. Methanol acidified with
acetic acid or made basic with sodium hydroxide was also ineffective at removing
significant amounts of TNT by-products from the compost.
The reduction of TNT to mono- and diamino nitrotoluenes has been reported
as the major route of TNT transformation -in the environment (McCormick et al.,
1976). In the composting process, however, only small amounts of these pr"oduc~ts
are formed or they are rapidly converted or polymerized into other compounds.
No TNT reduction products were found in the extracts from the 0 and 3 week
composts. The TLC analysis of the six-week composts contained small amounts
(0.9 to 2.0%) of i^C in an elongated region adjacent to the origin. The diamino
reduction product, 2,6-diamino-4-nitrotoluene, would have moved into this area
but would be expected to be present as a more discrete round spot than was
observed. However, it is possible that part of the ^C-activity in the
elongated region was present as 2,6-diamino-4-nitrotoluene. Two of three
replicates of the six week composts did not contain detectable levels of the
monoamino-DNT derivative. The extract from the third replicate had 1.1% of ^C-
activity tentatively identified as 4-amino-2,6-dinitrotoluene and 0.6% as 2-
amino-4,6-dinitrotoluene.
Complete destruction of TNT by breaking the benzene ring does not appear
to occur to any significant extent. Recovery of ^C as ^CC^ was negligible
(less than 1%).
43
-------
Table 19. Average Recovery of C as TNT From Compost After
0, 3, and 6 Weeks of Composting
Length of Composting % i^C-TNT Recovered1
0 weeks 93.5
3 weeks 46.6
6 weeks 16.6
^C-TNT recovered was determined by TLC analysis of
compost extracts. The percentage of total ^C-activity
present in compost extracts as ^C-TNT and as ^C-
labeled compounds other than TNT was determined by LSC.
44
-------
Degradation of RDX in compost is rapid and appears to result in the
complete destruction of the molecule. Recoveries of ^C as ^C02 were in excess
of 67% in individual replicates of the six-week composts. The average loss was
55.8%. The evolution of 1^002 was found to be inversely correlated to the
recovery of ^C-RDX in the solvent extract (R = 0.9695). It appears likely that
when the RDX ring is attacked, the entire molecule is rapidly metabolized.
Intermediate products, if any are formed, are readily assimilated by compost
organisms and a large percentage of the RDX carbon is released as C02- ^C-
labeled compounds other than RDX were not found in the solvent extracts
indicating that no build-up of solvent extractable intermediate products
occurs .
Because of the rapid conversion of 14C-RDX to 14C02, the plot of 14C02
versus time in Figure 6 can be used as an estimation of how RDX breakdown varies
with time. Significant recoveries of 1^C02 during the first four days of
composting suggested that RDX degradation began almost immediately. During the
first 11 to 15 days of composting, the rate of RDX breakdown was increasing.
From the second week through the fourth week of composting, the rate of
breakdown remained high. The ^C02 recoveries for the final two weeks of
composting suggest a slow decline in the rate of RDX metabolism.
After 3 weeks of composting, the residual ^C (^^C-activity in the compost
material following solvent extraction) accounted for 13.5% of the total
activity added to the compost (approximately 40% of the "C no longer solvent
extractable as l^C-RDX) . The amount of residual ^C in the compost after six
weeks of composting was not significantly higher although RDX breakdown in the
second three weeks of composting was substantial. Apparently secondary
metabolism of any ^C products formed from RDX was very rapid.
45
-------
V. GREENHOUSE COMPOSTING
A. Greenhouse Compost Set-Up and Sampling
1. Soil Spikes
Lakeland soil (air dried and sieved) was used as the carrier for
TNT. Two thousand grams of Lakeland soil were added to 500 mL of TNT solution
(40% production grade TNT in.acetone). The TNT concentration in the solution was
verified by GC analysis. The mixture was stirred, maintained at ambient
temperature in the dark and the acetone allowed to evaporate. Two replicates of
TNT contaminated soil were prepared by the above procedures for the TNT
greenhouse composts. Two thousand grams of the same Lakeland soil (no
additions) were used in the control compost in the greenhouse.
A stock acetone solution of production grade RDX was assayed by gas
chromatography and determined to contain 3.82% RDX. Two thousand grams of
Lakeland soil were dosed with 2,620 mL of RDX solution (100.08 g RDX/2000 g soil)
and treated as described above for the TNT soil spike.
2. Construction of Compost Chambers
Composting chambers were constructed of plywood. Dimensions
of the chamber are given in Figure 9. The inside surfaces of the chamber were
sealed with varnish and the outside surfaces were insulated with 3/4 inch
styrofoam insulation. A lid was constructed of a double layer of the foam
insulation.
Each of the composting chambers was placed in a glass 36 inch x 36
inch x 34 inch box. A layer of dry leaves was placed under and around the chamber
for insulation. A bag of leaves or hay was placed on the top of each chamber for
additional insulation.
Each compost box had provisions for pulling fresh air through the
compost materials. Fresh air entered the top of the box and was drawn through
the compost pile and out through a perforated polyethylene tube located beneath
the compost pile. The polyethylene tubes were connected to the suction end of
a blower. Air was drawn through the compost for a specified period during a ten
minute cycle.
3. Set-Up of Greenhouse Composts
Duplicate greenhouse composts for each explosive (RDX and TNT) were
set-up in a manner similar to the laboratory scale composts. A single untreated
(i.e. no explosives added) compost served as a control. The compost size was
approximately 10 Kg. The soil accounted for 2000 g of the mass. The bulk of the
compost was a 50:50 mixture of chopped alfalfa hay and horse feed. A portion of
the hay (approximately 500 g) was layered in the bottom of the composting
chamber to soak up leachate. The remaining hay and horse feed were mixed and
watered before the treated or uncontaminated soil was mixed in. A small amount
of seed compost or horse manure was slurried with water and added to initiate the
composting process.
46
-------
To Blower
1 inch Polyethylene Tubing
18 inch
1/8 inch Perforations in Tubing
Figure 9. Schematic of Greenhouse Compost Chamber
-------
The dry weights of the initial compost ingredients are listed in
Table 20. Some of the composts required several manure additions to start the
compost. During six weeks of composting, hay and horse feed were added to the
compost piles to maintain elevated temperatures. All additions and removals
were corrected for the moisture contents of the materials. The range
of moistures was, determined by drying at 80°C for 24 hours. The moisture
contents of the composts, the hay, the horse feed and seed materials are given
in Table 21.
4. Sampling Procedure
A chopped hay and horse feed compost is a relatively homogeneous
mass when viewed as a whole. However, small subsamples of such a compost (of a
size suitable for extraction to determine the RDX and TNT concentrations) are
not homogeneous, but may vary greatly between samples. Therefore, the initial
samplin^ of both the RDX and TNT composts (greenhouse scale) was designed to
provide information on the effect of sub sample size on . the accuracy of
determining the concentration of explosives in the compost.
Three 20 g and three 50 g (wet weight) subsamples were removed from
each of the two TNT and RDX replicates. Subsamples were obtained by mixing the
compost and removing a number of grab samples. These samples were combined and
mixed, and then the 20 and 50 g subsamples were removed from the sample. Several
additional samples were also removed for moisture determination. The remaining
sample of compost was mixed back into the compost. The subsamples were
extracted with acetone for RDX analysis and with benzene:methanol for TNT
analysis. The extracts were analyzed by GC as described in Section IV and
Appendices B and C. The results are presented in Table 22. The variability
between subsamples for both explosives is high, as indicated by the standard
deviation. The variability in the RDX samples is particularly high. This
variability is the result of crystallization of RDX in the treated soil. Soil
particles were cemented together when the RDX crystallized resulting in
relatively large aggregates. Attempts to crush these aggregates were only
partially successful, therefore, RDX could not be as evenly dispersed in the
compost as the TNT. A one-way analysis of variance, Model II, was utilized to
find which subsample size gave a more precise estimate of the explosive
concentration. The ANOVA's for both RDX and TNT are presented in Table 23. The
F ratios were not significant for either RDX or TNT indicating that the sample
size did not significantly influence the precision of determining TNT or RDX
levels in compost. The standard deviation for the 50 g subsamples was
substantially lower than that for the 20 g samples, therefore, 50 g subsamples
with four subsamples per replicate were used in all subsequent samplings.
B. Results
1. Routine Monitoring of Greenhouse Composts
Three thermocouples were inserted in the center of each compost:
one 11.5 to 13 cm (4.5-5 inches) from the bottom; one 23 to 25 cm (9-10 inches)
from the bottom and one 34 to 38 cm (13.5-15 inches) from the bottom. The
48
-------
Table 20. Greenhouse Compost Ingredients
Weight in Crams
Compost
Box
1
2
3
4
5
Explosive
0
100 RDX
100 RDX
200 TNT
200 TNT
Soil
2000
2000
2000
2000
2000
Hay
4815
3900
3900
3900
4815
Kcrse Feed
3900
3900
3900
3900
3900
Seed
Compost
121
0
0
121
121
Manure
0
465
465
0
0
Total
10836
10265
10265
9921
10836
-------
Table 21. Moisture Contents of Greenhouse Compost and
Compost Components .
Material 7, Moisture
Hay 7.5-8.5
Horse Feed 8.4 - 12.3
Seed Compost 67.8
Horse Manure 50.9 - 61.3
Compost - 0 week 52.2 - 61.6
Compost - 3 week 51.6 - 72.0
Compost - 6 week 63.2 - 67.3
50
-------
Table 22. RDX and TNT Concentrations in Greenhouse Composts at
Time Zero Sampling
Subsample Size
(wet wt)
replication
Concentration of
Explosive (ppm)
RDX 20 g 1 9794
9297
18727
2 12839
7081
5967
50 g 1 9097
7435
10267
2 15434
8659
6502
TNT 20 g 1 18154
20789
14804
2 20431
22574
19080
50 g 1 19128
20694
24502
2 20302
18279
21578
_*
X
S
X
S
X
S
X
S
X
S-
X
S
X
S
X
S
12606
5307
8629
3688
8933
1423
10198
4661
17916
3000
20695
1762
21441
2764
20053
1664
*x -
S -
arithmetic mean
standard deviation
51
-------
Table 23. Analysis of Variance Examining Subsample Size for Greenhouse
Scale RDX and TNT Composts
RDX
Ul
Source of Error
Among subsample
Within subsample
Total
20 g subsample
50 g subsample
TNT
sizes
size
X
S
X
S
Source of Error
Among subsample
Within subsample
Total
20 g subsample
50 g subsample
sizes
size
X
S
X
S
r/egrees of Freedom Sums of Squares
1 116704
2 8708377
3 9815081
10618
2812
9566
894
Degrees of Freedom Sums of Squares
1 2077922
2 4824693
3 6902615
19306
1965
20747
981
Mean Square F Ratio Probability
1106704 0.25417 0.664
4354189
Mean Square F Ratio Probability
2077922 0.86137 0.451
2412346
'
X = arithmetic mean
^ = standard deviation
-------
middle thermocouple is plotted as a function of time in Appendix D. In the TNT
and control composts, the temperatures at the bottom of the compost were
slightly cooler on the average than the temperatures in the middle. The top
thermocouple readings were within 2°C of the temperatures in the middle of the
compost. The temperatures at the bottom of the RDX composts were consistently
as warm as, or slightly warmer than, the temperatures in the middle of the box.
The thermocouple readings from the top of the compost were consistently cooler
than the temperature in the middle of the compost.
The air removed from the composts by the aeration system was sampled
weekly for GC analysis of its 02 and C02 contents. The results are presented in
Appendix E. The 02 levels ranged from 4.5% to 20.3% of the air. At no time during
the composting period did analysis indicate that the composts had become
anaerobic.
2. Compost Extraction and Analysis
The RDX composts were subsampled after 0, 3, and 6 weeks of
composting. Because of the rapid decrease in extractable TNT, the TNT composts
were subsampled after 0, 3 and 4 weeks of composting. The subsamples were
extracted with acetone for RDX recovery and benzenermethanol for TNT recovery.
Quantification of the explosives was by GC analysis as described in Section II
and Appendices B and C. Concentrations of explosives in the composts are
presented in Tables 24 and 25. Subsamples for the control compost were spiked
with standard solutions of explosive at each sampling time, extracted and
analyzed in the same manner as the experimental composts. Results of the quality
control analyses are presented in Tables 26 and 27.
The recoveries of TNT and RDX from the compost were analyzed in a
one way analysis of variance. The RDX data did not lack homogeneity of variance
at the 5% level of probability according to Cochran's Test (Chemical Rubber
Company Handbook, 1968). There was insufficient data to test the homogeneity of
variance of the TNT results, therefore, no data transformation was used. The
significance testing was at the 5% level. Where significant differences were
indicated by the analysis of variance, the Student-Newman-KueIs Multiple Range
Test was used to separate means. The results of the analysis of variance
are presented in Table 28.
C. Discussion and Conclusions
Composting of TNT on a greenhouse scale resulted in rapid disappearance
of solvent extractable TNT from compost. Analysis of solvent extracts at three
weeks showed that TNT concentrations were below the detection limit indicating
that the process by which the TNT concentration is reduced during composting
occurred more rapidly in the greenhouse compost than in the laboratory scale
composts. Greenhouse compost temperatures were variable but, in general, were
higher than the temperatures recorded for the laboratory composts. It is
possible that the elevated temperatures enhanced the disappearance of TNT from
the compost material.
53
-------
Table 24. TNT Concentration in Greenhouse Compost Material
yg/g in Compost
Sample
Box 1
(control)
Box 4
Box 5
Tc, Week
<16.9
19,678
20,404
T-? Week
<16.9*
<16.9
<16.9
1'4 Week
<16.9
<16.9
<16.9
*Detection Limit for Quantification of TNT from Compost was 16.9 pg/g
Table 25. RDX Concentration in Greenhouse Compost Material
yig/g in Compost
Sample
Box 1
(control)
Box 2
Box 3
Tn Week
ND*
9,240
9,414
T-5 Week
ND*
3,284
5,093
Tft Week
ND*
3,142
1,277
*Detection Limit for Quantification of RDX from Compost was 794.7 /ig/g
54
-------
Table 26. Quality Control: TNT Compost Sampling
QC Sample
A
B
C
D
Target
30
77
153
460
.7
.0
.0
.0
ppm
ppm
ppm
ppm
Ug/g
Found - T0
40.1
75.8
175.5
500
Found
41
77
143
467
- Tn,
.3
.8
.5
.8
Ug/g
QC Sample Target Found -
A 4.6 4.8
B 9.2 7.0
C 25.2 26.0
D 50.4 50.0
55
-------
Table 27. Quality Control: RDX Compost Sampling
QC Sample Time
A zero
B
C
D
A 3 week
B
C
D
A 6 week
B
C
D
Target
1180
2359
4444
9196
1569
3138
6275
12551
1170
2340
4680
9359
Found
922
2027
4719
9438
1245
2640
5040
9480
740
2404
4345
9329
56
-------
Table 28. Analysis of Variance for TNT and RDX Levels in Greenhouse Composts
Parameter Source of Error Degrees of Freedom Sums of Squares Mean Squares F Ratio Probability
TNT Time
Error
Total
RDX Time
Error
Total
2
3
5
2
3
5
55467806
3375371
58843177
534614101
263538
534877639
27733903 24.6496
1125124
267307051 3042.9052
87846
0.01374
0.00001
-------
Breakdown of RDX in the greenhouse compost was initially much more
rapid that that observed in laboratory composts. After three weeks of
composting, RDX levels in the greenhouse scale composts were reduced by 61%,
compared to an average of 39% reduction observed in the laboratory composts. It
should be noted that the RDX concentration in the greenhouse compost after three
weeks is neither corrected for additions of cmposting materials nor for the loss
of compost mass through microbial respiration and is thus an approximation. The
entire compost must be weighed to calculate mass reductions via respiration.
This measurement could only be made at the conclusion of the experiment.
Total reduction of RDX by composting for six weeks averaged 82% and
31% from the greenhouse and laboratory compost, respectively. The close
agreement between the greenhouse and laboratory composts indicates that bench
scale composts would be accurate in predicting the metabolism of RDX in large
scale composts. The greenhouse composts generally composted at higher tempera-
tures. This difference in temperature did not have any apparent effect on RDX
breakdown.
Collectively the results from the laboratory and greenhouse com-
posts indicate that both RDX and TNT concentrations are rapidly decreased by
composting. The laboratory composting equipment and conditions used in this
study were sufficient to provide a good estimate of the breakdown of explosives
in larger scale composts. These conditions can likely be altered to improve the
accuracy of the bench scale composts for use in predicting what occurs in full
size composts.
58
-------
VI. LEACHATE STUDY
The methodology used in the leachate studies is outlined in Table 29 and
discussed along with the results in the following paragraphs. .
A. Preliminary Study
The objective of the preliminary study was to measure the maximum water
holding capacity of composted materials. This study was necessary to determine
appropriate procedures to be used in obtaining aqueous extracts of the compost.
Evaluation of alternative methods for clarifying the aqueous extract was
included in this study.
1. Water Holding Capacity
Several techniques for determination of water holding capacity of
compost were attempted. The compost was sampled and percent moisture determined
by drying at 60°C for 24 hours. Compost samples were weighed onto filter paper
or paper towels which were supported by metal screens. Other samples were
wrapped in a variety of materials; cheesecloth (3 layers), lens paper (single
thickness) and Kimwipes (single thickness). All samples were saturated with tap
wate* for at least 45 minutes and allowed to drain. Time required for complete
draining was excessive, requiring more than 24 hours in some cases. The volume
of water retained by the compost was corrected for the water absorbed by the
support materials (filter paper, towels, etc.); however, the results were too
variable to be considered reliable.
As .an alternative method, compost was mixed with a known volume of
water in a 100 mL graduated cylinder and allowed to absorb water for one hour.
The compost was then compressed into the bottom of the cylinder and the free
water decanted. The volume of free water was measured and recorded. Two
composts were used in these studies* a three-week old chopped hay and horsefeed
compost and a similar compost that was started approximately nine months prior
to use. The results of these tests are summarized in Table 30. The water
retention ratios observed were relatively consistent. The three week old
compost was not as putrefied as the nine month old material and therefore, had
a much lower water holding capacity. Composts to be extracted in the leachate
study to estimate leachable TNT, RDX and metabolites will be up to six weeks old.
The water retention of a six week old compost will be between that determined for
the 3 week and the 9 month old composts. Therefore, a 6:1 ratio of water to
solids was selected to insure a sufficient volume of sample for analysis.
59
-------
Table 29. Summary of Leachate Compost Studies -
1) Preliminary Study - determine water retention capacity
of compost at varying stages of composting.
2) Compost - 58 g (dry weight) hay and horsefeed compost
dosed at 12 RDX or 1% TNT.
3) Compost Procedure -
a. Composting carried out in a 55°C incubator
b. Compost continuously aerated with humidified
and warmed CO2 free air
c. Two replicate composts sacrificed after 0, 3
and 6 weeks of composting for aqueous extraction
to determine TNT and RDX losses in leachate.
60
-------
Table 30. Absorption of Water by Composted Material
Compost
9 month
3 week
Compost
Wet
20.88
20.00
20.51
20.45
21.9
Weight (g)
Dry*
3.88
3.08
3.16
3.15
10.42'
H20 Added
(mL)
10.0
20.0
30.0
40.0
69.7
H20 Retained**
(inL)
23.21
22.12
21.11
22.25
40.43
Ratio of
Liquid to
Solid
7.2
7.2
6.7
7.1
3.9
*Dried 24 hours at 60°C
**Total water retained in compost; includes water already in compost (wet
weight - dry weight) plus any additional water absorbed.
61
-------
2. Clarification of Aqueous Extract
Clarification of the extract obtained from the compost was at-
tempted by filtering through several types of filter paper, glass wool, sand,
and by centrifugation. It was found that filtration through glass wool to remove
the larger particulates, followed by centrifugation to remove most of the
remaining particulates, followed by filtration through Whatman No. 42 filter
paper was the most efficient method for removing the particulate matter from
solution.
B. Leachate Study
Twelve 50 g composts were prepared with TNT or RDX added as 1% of the
compost to each of six flasks. The moisture content of chopped alfalfa hay,
Purina Sweetena horsefeed and seed compost was determined by drying at 80°C for
24 hours. The hay (18.5 g dry weight), horse feed (18.5 g dry weight) and seed
compost (3 g dry weight) were combined with Lakeland soil previously treated
with TNT or RDX. Methods of treating the soil and mixing the compost were as
described in the Preliminary TNT Laboratory Compost section of this report. The
final water content of the compost was adjusted to 60% (wet weight basis). The
composts were placed in an incubator at 55°C and aerated as were the control
composts in the preliminary TNT compost study (see Figure 2).
The temperatures of the composts were monitored daily. Individual
compost temperatures ranged from 50 to 62°C. The average temperatures of the
TNT and RDX composts and the average air temperature of the incubator are
plotted against time in Figure 10. The TNT composts averaged 2.3°C higher than
the air temperature in the incubator. The RDX compost temperatures averaged
4.8°C higher than the incubation.
Duplicate samples of the compost were sacrificed at time zero and after
3 weeks and 6 weeks of incubation. The samples were extracted for 20 hours with
distilled wate- to simulate a worst case example of leaching by rain in a field
operated comp
C. Results
Analysis of the RDX compost leachate at time zero indicated that 7.4% of
the RDX (approximately 124 ppm) was leached into the water extract. A
significant decrease in RDX leaching was observed after composting with 3.2%
(approximately 52.5 ppm) detected at 3 weeks and 0.8% (13 ppm) after six weeks
of incubation.
Analysis of the TNT compost leachate at time zero showed that TNT was not
leached into the water extract in detectable amounts from fresh compost
materials. Leachate analysis at three weeks of incubation showed that 5.9% of
the TNT was present in the leachate (approximately 98 ppm), indicating that TNT
is more readily extracted with aqueous or polar solutions from composted
material than from the fresh compost materials. After six weeks of composting,
the TNT leachate contained 0.08% of the TNT (1.4 ppm)
62
-------
61 -
60 -
57
58
o
c
56 -
55 -
2. 54
E
3
u
01
>
52 -
51 -
50 -
0 TNT
A RDX
Q Incubator
10
20 30
Time Composting (Days)
Figure Id Comparison of Compost Temperatures for Leachate Study
63
-------
D. Conclusions
The leachate study was performed under conditions designed to illustrate
a "worst-case" example. The soil containing the TNT or RDX was a sand with less
than 5% clay and silt, and approximately 1% organic matter. Such a soil is
expected to have a relatively low capacity to adsorb and retain organics such as
TNT or RDX. The twenty hour extraction at room temperature prior to removal of
the aqueous leachate would likely result in TNT and RDX concentrations far
greater than would normally be found following rainfall and leaching from an
outdoor compost pile. The decrease in RDX concentration in the leachate
following composting corresponds to the biodegradation of this explosive during
the incubation period.
The very small amounts of TNT found in the aqueous extracts of the TNT
composts indicate that TNT is not readily extracted from fresh compost materials
by polar solvents. During the initial three-week composting period, the
adsorption of TNT to the compost materials appears to be altered with an
increased quantity of TNT leaching into the extract. The subsequent decrease in
TNT concentrations in the 6-week leachates corresponds to the disappearance of
TNT during the incubation period.
64
-------
VII. REFERENCES
Block, C.A. editor (1965), Methods o_f Soil Analysis, Part 2. Chemical and
Microbiological Properties, American Society of Agronomy, Madison,
Wi.-consin, p. 1171-1175.
Chemical Rubber Company (1968), Handbook p_f Tables for Probability and
Statistics, CRC, Cleveland, Ohio. Cochran's Test for the Homogeneity of
Variances, p. 325-327.
Hoffsommer, J.C.; L.A. Kaplan; D.J. Glover; D.A. Kubose; C. Dickenson; H. Goya;
E.G. Kayser; C.L. Groves and M.E. Sitzmann (1978), "Biodegradability of
TNT: a three year pilot study," Naval Surface Weapons Center, White Oak,
NSWC/WOL TR 77-136.
McCormick, N.G.; F.E. Feeberry and H.S. Levinson (1976), "Microbial trans-
formation of 2,4,6-trinitrotoluene and other nitroaromatic compounds,"
Appl. Environ. Microbiology, 3_U6), p. 949-958.
Sokal, R.R. and F.J. Rohlf (1969), Biometry. W.H. Freeman and Co., San
Francisco.
Won, W.D.; R.J. Heckley; D.G. Glover and J.C. Hoffsommer (1974), "Metabolic
Disposition of 2,4,6-trinitrotoluene," Appl. Micro. , 2^7_(3), p. 513-516.
65
-------
APPENDIX A. SYNTHESIS OF 14C-LABELED RDX
67
-------
Two mL of concentrated NH^OH are slowly aded with mixing to 2 mL of
40% formaldehyde (containing 250 M Ci of ^C-formaldehyde) to form a hexamine
solution.
To the hexamine solution, 0.45 mL of 70% nitric acid is slowly added
with mixing in an ice-salt bath at 5-15°C. An additional 0.3 mL nitric acid
is added to cause precipitation. The solution is maintained at 5°C for an
additional 15 minutes. The sample is then centrifuged, the liquid drawn off
and discarded. The resulting crystals are dried in a vacuum oven at room
temperature. A yield of approximately 1 g hexamethylenetetramine-dinitrate
is obtained.
To the dried salt, 0.623 g finely divided ammonium nitrate is added and
thoroughly mixed.
0.7 mL of 98% nitric acid is added slowly to a test tube containing
2.65mL of acetic anhydride cooled to 5-15°C in an ice-salt bath.
In another tube, a small amount of the solid and the liquid mixtures are
added together and quickly heated in a water bath to 70-80°C. Small amounts of
the solid and liquid mixtures are added until all of the solid and liquid have
been used. The mxiture is allowed to heat for an additional 15 minutes and then
cooled to 15°C to precipitate the RDX.
The cooled mixture is centrifuged, the liquid drawn off, the crystals
rinsed with 2 mL cold water and again centrifuged. The liquid is drawn off, and
the RDX crystals dried in a vacuum oven at room temperature.
69
-------
APPENDIX B. ANALYSIS OF TNT IN COMPOST - QUANTITATIVE
71
-------
1. APPLICATION
Method used to determine the concentration of TNT in compost.
A. Tested Concentration Range: (yg/g)
5.6 yg/g to 110.8 yg/g
B. Sensitivity:
1091 area units/pg based on a 35.4 pg injection
C. Detection Limit: (yg/g)
16.9 yg/g
D. Interferences; Interferences were encountered which could be
attributed to compost components, the presence of phthalate esters or their
plasticizers.
E. Analysis Rate: Extraction requires 1.5 hours to complete. One
analyst can extract and analyze 12 samples per 8-hour day.
2. CHEMISTRY
C7H5N30$. Toluene, 2,4,6-Trinitro-
CAS RN 118-96-7
Melting Point: 80.75°C
Boiling Point: 240°C (explodes)
Hazards: Use caution in handling this compound; explosive and toxic
hazards exist.
3. APPARATUS
A. Instrumentation;
Gas Chromatograph - Hewlett-Packard 5880A with computer controller
and integrator, autoinjector, and electron capture detector.
73
-------
B. Parameters:
Column - 1.5% OV17/1.95Z OV210 on 80/100 Anakrom Q in a 2 mm
I.D. , 0.125 in O.D. by 6 ft. glass column
Temperature - injection port - 210°C
oven - 180°C
detector - 300°C
Temperature Programming - isothermal
Carrier Gas - nitrogen at 28 cc/min.
Detector - electron capture
Injection Volume - 2 yL
Retention Time - 3.2 min.
C. Glassware/Hardware:
Volumetric Flask - 2 mL (2)
Volumetric Flask - 50 mL (1)
Volumetric Flask - 25 mL (3)
Volumetric Pipets - 5 mL (2)
Volumetric Pipets - 1 mL (3)
Volumetric Pipets - 1/2 mL (1)
Filter Paper, Fisher qualitative 42
Glass Funnels - 9 cm (6)
Glass Graduated Cylinders - 500 mL (6)
1 Quart Mason Jars (6)
Finn Pipets (adjustable) - 200 - 1000 yL
Finn Pipetts (adjustable) - 50 - 200 yL
Finn Pipetts (adjustable) - 5 - 50 yL
GC Autosampler Vials with Teflon Inserts (10)
Aluminum Foil
Waterbath - 37°C
Refrigerator
Test tubes, glass (6)
D. Chemicals;
TNT "SARM"- PA 360, Lot #268
Benzene, certified (Fisher Scientific)
Methanol, certified (Fisher Scientific)
4. STANDARDS
A concentrated stock solution of TNT is prepared by weighing out the
following amount of SARM material into a volumetric flask and bringing to volume
with benzene.
14.2 mg in 100 mL = 142 mg/L (I)
The volumetric flask is wrapped in aluminum foil and stored in the
refrigerator until needed. Storage time should not exceed two months.
74
-------
A. Calibration Standards: Calibration standards are prepared from the
stock solution by dilution with benzene according to the following scheme:
.5 ml of I to 20 mL
2 mL of II to 10 ml
1 mL of II to 20 mL
1 mL of III to 10 mL
1 mL of IV to 10 mL
B. Control Spikes;
3.55 mg/L (II)
710 yg/L (III)
177 yg/L (IV)
71 yg/L (V)
17.7 yg/L (VI)
20 grams.
Control spikes are prepared as follows:
20 mg TNT SARM in 50 mL benzene * 400 yg/mL (A). Compost weight is
5.
10 DL
5 DL
2 DL
1 DL
.5 DL
Blank
PROCEDURE
5.54 mL of A
2.75 mL of A
1.10 mL of A
0.55 mL of A
0.28 mL of A
0 mL of A
110.8 yg/g
55.0 yg/g
22.0 yg/g
11.0 yg/g
5.6 yg/g
0 yg/g
Four grams of Lakeland sand are weighed into each of six 50 mL beakers.
Each beaker of sand is dosed with the appropriate amount of TNT stock. After the
spike, each beaker is covered with aluminum foil and placed in the dark at room
temperature overnight.
Each dosed soil is added to 16 grams compost (dry weight) and mixed in one
quart Mason jars. After mixing, the jars are wrapped in foil, and placed in the
dark at room temperature for one hour.
The extraction is carried out with 160 mL benzene:methanol (75:25). Warm
extractant, 160 mL,is added to each Mason jar and the jars are placed in a 37°C
waterbath. All jars are agitated at 5 minute intervals. Jars are removed from the
waterbath after 30 minutes. The liquid extract from each jar is filtered through
filter paper in a glass funnel. The filtrate is collected in glass test tubes.
The samples.are diluted for analysis by the following procedure:
DL mL Extract mL Benzene Dilution
0
0.
1.
2.
5.
10.0
1
1
5
5
1
0.5
1
1
20
45
24
24.5
1:2
1:2
1:5
10
25
1:50
All dilutions are made using volumetric pipets and volumetric flasks.
75
-------
TNT analysis by GC may be accomplished with flame ionization (FID) or
electron capture (EC) detectors. The detection limit with FID is 50 ppm and
requires concentration of the compost extract for analysis. Concentration of the
compost extract before analysis is not feasible because of the interferences
present in the extract. The range for detection of TNT with EC is 15-500 ppb.
Thus, the compost extracts must be diluted to fall within this analytical range.
Dilution of the extracts decreases the interferences caused by the compost
components, phthalate esters or their plasticizers.
Inject 2 yL of the diluted extract onto the GC column in duplicate.
Run standards singly at the beginning and end of each run
Plot peak area versus ppb injected to obtain standard curves for TNT.
6. CALCULATIONS
i
The concentration of explosive (ppb) in the sample is read directly from
the standard curve. The apparent concentration of explosive in the compost is
calculated from the formula given below:
. , i . 120 mL extract x .001 x reciprocal of extract dilution
Concentration (ppm) = ppb x — TTT . , ,
g dry weight compost (50 g wet weight)
7. REFERENCE
Lindner, V. (1980), "Explosives and Propellants," Kirk-Othmer Ency-
clopedia Chemical Technology, 3rd edition, John Wiley and Sons, NY, 2:561-671.
76
-------
Target
Concentration
TNT IN COMPOST
Days
3
11 2/01
Blank
0
0.5X
5.6
X
11.0
2X
22.0
5X
55.0
10X
110. S
0.30
3.55
9.15
14.70
45.00
108.30
0.37
3.89
8.37
17.16
45.45
95.70
0.08
2.80
6.45
15.66
37.80
91.50
0.28
3.60
7.59
22.50
52.50
89.70
Target
Concentration.
Average
Found Value
Standard Percent Percent
Deviation Imprecision Inaccuracy
pg/g
Blank
0
0.5X
5.6
X
11.0
2X
22.0
5X
55.0
10X
110.8
.26
3.46
7.89
17.51
45 . 19
96.30
.47
1.15
3.48
6.00
8.39
13.48
14.6
19.9
13.3
8.7
-38.2
-28.3
-20.4
-17.8
-13.1
77
-------
3 u rt c ! \ v
S 0 M V * N *
SUMO\
SUMlXv
x»
Y«
LINE
1
2
3
4
5
£
7
a
9
10
11
12
13
14
IS
16
17
18
19
28
21
22
23
24
i > =
1 t f ' M
i > r2»
1 )*Y( l )*
314.000
6304 1 . 0
3427
1.1331 Y * 1.
8.8736 X * -1.
TC
0.0000
0.0000
0.0000
0.0000
5.5000
5.5000
5. 5000
5.3000
11.0000
1 1 . 0000
1 1 . 0000
1 1 . 0000
22.0000
22. 0000
22.0000
22.0000
55.0000
53.0000
55.0000
55.0000
110.8000
110.0000
110.0000
110.0000
STANDARD ERROR
C
0.3000
0.3720
0.0340
8.2760
3.5520
3.3330
2.7960
3.6000
9.1500
8.3700
6.4300
7.5900
14.7080
17.1600
15.6600
22.5000
45.8000
45.4308
37.3000
52.5000
103.3000
95.7000
91.5000
89.7000
0
iK"'»
6^'2 TNT IN CO
6. 'a430
3537 CORR
3669 CORR
C
-1.3669
-1.3669
-1 .36^'
-1/3669
3.4656
3.4636
3.4636
3.4636
8.2930
3.29SO
3.2930
3.29SO
17.9629
17.9629
17.5629
17.9629
46.9577
46.9577
46.9577
46.9577
95.2322
95.2822
95.2322
95.2322
. COEF.*
. CQEF.»
DELTfl
1.6&6?
1.7:39
1.4T09
1.6429
O.OJ64
0.4224
-0.6e96
0.1344
0.8520
0.0720
-1 . 3-50
-0.7030
-3.2629
-0.3029
-2.3029
4.3371
-1.9577
- 1.5077
-9. 1577
5.3423
13.0173
0.417S
-3.7S22
-5.5322
OF ESTIMflTE
1.0880
£.1147
upper confidence lin* at X«
lower confidence line at X*
STflNDflRD DEVIATION flT X«
PERCENT INflCCUPflCY flT X»
PERCr>iT IMPRECISION flT X»
HEflh- 1UND flT X»
onfidence lin* at X*
low« Confidence line at X*
STftNDftRD DEVIATION flT X«
PERCENT INflCCUPflCY flT X«
PERCENT IMPRECISION flT X»
MEAN FOUND flT X«
u»ner confidence line at X«
lower confidence line at X>
STflNDflPD DEVI flT I ON flT X«
PERCENT INftCCURflCY flT X«
PERCENT IMPRECI2IOH flT X»
HEftN FOUND flT X«
u»»«r confidence line at X«
lower confidence line at X»
STRNDrtPD DEVIhTIOH AT X«
PERCENT tUflCCUPSCY flT X»
PERCENT IMPPECrSIOri flT X»
HEflN FOUND flT ::•
5.3000 is
3.5940 is
3-3000 is
5.5000 IS
5.5000 IS
S.5000 IS
11.0000 is
11.0000 is
11.0000 is
11.0000 IS
11.80*00 IS
IS
11.8080
22.0808
53.8080
22.0000 is
22.0000 is
22.0000 is
22.0000 13
22.8000 IS
IS
53.0006 is
53.0000 is
35.0000 13
35.0000 IS
55.0000 IS
IS
u»»er confidence line at
layer cont vd-ince line at
STflNDfiPD DEVIATION flT X-
PERCENT INACCURACY flT X»
PERCENT IMPRECI3ION flT X
tlEAN FOUND flT :;=
X* 110.0000 is
X* 110.0000 is
110.0000 is
110;8000 IS
110.0000 IS
110.0000 IS
3.4598
10.9134
-3.9822
0.4662
-37.1091
13.4799
7.3900
13.7179
8.8731
1.1520
-28.2727
14.6013
17.5850
25.3447
10.5311
3.4805
-20.4313
19.3827
45.1375
54.3695
39.5458
6.0042
-17.340?
13.2373
9-5.2000
183.20*6
87.3579
3.3357
-12.4543
3.7079
I DETECTIOII LIMIT » 16.93:2 I „„/,
78
-------
APPENDIX C. ANALYSIS OF RDX IN COMPOST - QUANTITATIVE
79
-------
1. APPLICATION
Method, used to determine the concentration of RDX in compost.
A. Tested Concentration Range: (yg/g)
630 to 12600 yg/g
B. Sensitivity:
7150 area units/ng based on a 23.4 ng injection
C. Detection Limit: (yg/g)
794.7 yg/g
D. Interferences: Major interferences in RDX analysis were en-
countered due to the acetone extraction of many compost components as well as
RDX. A number of the components in the extract eluted from the GC column at
approximately the same time as RDX. Separation of these components from RDX to
allow quantitation is extremely difficult.
E. Analysis Rate; Extraction requires 3 hours to complete. One
analyst can extract and analyze 12 samples per 8-hour day.
2. CHEMISTRY
C3^6^606 Hexabydro-1,3,5-trinitro-l,3,5-triazine
CAS RN: 121-82-4
Melting Point: 204°C
Boiling Point: Not available
Hazards: Use caution in handling RDX; potential explosive and toxic
hazards exist.
3. APPARATUS
A. Instrumentation;
Gas Chromatograph - Hewlett-Packard 5880A with computer controller
and integrator, autoinjector and electron capture detector.
81
-------
B. Parameters:
Column: 10% SE30 on 80/100 Supelcoport in a 2 mm I.D.,
0.25 in O.D. by 2 ft. glass column
Temperature: injection port - 210°C
oven - 180 to 210°C
detector - 340°C
Temperature Programming: 10°C/min.
Carrier Gas: nitrogen at 30 cc/min.
Detector: electron capture
Injection Volume: 2 yL
Retention Time: 3.90 min.
C. Glassware/Hardware:
Glass filter flasks (6)
Glass beakers, 50 mL (6)
Filter paper, Fisher qualitative medium #42
Buchner funnel, plastic, 9 cm (4)
One quart Mason jars (6)
Finn pipette adjustable, 200-1000 yL
Finn pipette adjustable, 50-200 yL
Finn pipette adjustable, 5-50 yL
Volumetric pipets, 1 mL (9)
Volumetric pipet, 2 mL (1)
Volumetric pipets, 5 mL (4)
Volumetric flasks, 100 mL (4)
Volumetric flasks, 10 mL (10)
Graduated cylinders, 500 mL (6)
Water bath, 37°C
Aluminum foil
Refrigerator
D. Chemicals:
RDX "SARM", Lot #HOL475-1, PA 361
Acetone, ACS certified (Fisher Scientific)
Benzene, ACS certified (Fisher Scientific)
Anhydrous Sodium Sulfate, ACS certified (Fisher Scientific)
4. STANDARDS
A concentrated stock solution of RDX is prepared by weighing out the
following amount of SARM material into a volumetric flask and bringing to volume
with acetonitrile:
93.44 mg to 100 mL = 934.4 mg/L (I)
The volumetric flask is wrapped in aluminum foil and stored in the refrigerator
until needed.
82
-------
A. Calibration Standards; Calibration standards are prepared from the
stock solution by dilution with benzene according to the following scheme:
5 mL of I to 100 mL = 47.6 mg/L-(II)
2.5 mL of I to 100 mL - 23.4 mg/L (III)
5 mL of III to 10 mL = 11.7 mg/L (IV)
1 mL of II to 10 mL = 4.8 mg/L (V)
1 mL of III to 10 mL = 2.3 mg/L (VI)
1 mL of IV to 10 mL - 1.2 mg/L (VII)
B. Control Spikes;
Control Spikes are prepared as follows:
4.2 g of RDX to 100 mL acetone = 42,000 mg/L (A)
Compost weight is 20 g (dry weight)
10 DL 6.0 mL of A = 12600 yg/g
5 DL 3.0 mL of A = 6300 yg/g
2 DL 1.2 mL of A = 2520 yg/g
1 DL 600 yL of A = 1260 yg/g
0.5 DL 300 yL of A - 630 yg/g
Blank 0 mL of A * 0 yg/g
5. PROCEDURE
Four grams of Lakeland sand are weighed into each of six 50 mL beakers.
Each beaker of sand is dosed with the appropriate amount of RDX stock. Each
beaker is covered with aluminum foil and placed in the dark at room temperature
overnight.
Each dosed soil is added to 16 grams (dry weight) compost (50 g wet
weight) and mixed in one quart Mason jars. After mixing, the jars are wrapped
in foil and placed in the dark at room temperature for one hour.
Three extractions are carried out with acetone. Warm acetone, 160 mL, is
added to each Mason jar and the jars, are placed in a 37°C water bath. All jars are
agitated at 0, 10 and 20 minutes. Jars are removed from the water bath after 30
minutes. The liquid extract from each jar is filtered by vacuum through two
layers of filter paper in a Buchner funnel. The filtrate is collected in 500 mL
glass filter flasks. The flask containing the filtrate is covered with foil
while the second and third extractions are performed. Following the third
extraction, the final volume of filtrate (composite of extracts 1, 2 and 3) is
measured in a 500 mL graduated cylinder. The extracts are prepared fcr GC
analysis by diluting 0.5 mL aliquots to 10 mL with benzene. The benzene is then
dried with anhydrous sodium sulfate and loaded into GC autosampler vials (see
note).
83
-------
Inject 2 yL of the diluted extract into the GC column in duplicate.
Run standards singly at the beginning and end of each run.
Plot peak areas versus yg/L of standard injected to obtain-standard curve
for RDX.
6. CALCULATIONS
The concentration of explosive (ppm) in the sample is read directly from
the standard curve. The apparent concentration of RDX in the compost is
calculated from the following formula:
concentration (ppm) *
ppm x total volume of extract (mL) x .001 x reciprocal of extract dilution
20 g dry weight compost (50 g wet weight)
7. REFERENCE
Lindner, V. (1980), "Explosives and Propellants," Kirk-Othmer Encyclo-
pedia Chemical Technology, 3rd edition, John Wiley and Sons, NY, 2:561-671.
8. NOTE: Several clean-up procedures were evaluated to remove compost
interferences from RDX. These procedures either did not remove the inter-
ferences or also removed the RDX. Since the composting task was not for
analytical methods development, it was decided to dilute the interferences out
instead of spending a significant amount of additional time and monies in
analytical methods development. As a result of the dilution, a high detection
limit had to be accepted.
9. NOTE: Column clean-up of the acetone extracts of compost were investi-
gated. Residual water was first removed from the acetone by pressing the
acetone extract through anhydrous sodium sulfate. The dried extracts were
passed through activated enutral alumina prior to GC analysis. Dried extracts
were also passed through activated fluorasil and through Nuchar Attaclay in
attempts at extract clean-up. Acetone extracts were also shaken with Nuchar
Attaclay followed by centrifugation prior to analysis of the extract by GC.
Solvent exchange was investigated for sample clean-up by evaporating
the acetone extract to dryness and redissolving the residue in methylene
chloride. The methylene chloride extract was washed with water or 1 M HC1
prior to analysis.
The use of N-P detector was also investigated. RDX detection limits
using the N-P detector were similar to those of the FID. Interferences using
the N-P detector were similar to those encountered with the electron capture
detector .
84
-------
RDX IN COMPOST
Target
ConccnLrac ion/Hay
Ug/g
Blank
0
o.5>:
630
X
1260
2X
2520
5X
6300
_
10X
12600
0
528
1562
2904
6593
13008
0
756
1305 .
2344
5719
12212
0
566
1202
2359
6020
9701
1
o
731
1392
2596
6438
I
9592
Target
Coneen eration/Day
Average
Found Value
Standard Percent Percent
Deviation Imprecision Inaccuracy
yg/g
Blank
0.5X
630
X
1260
ft
2520
5X
6300
10X
12600
0
645.3
1365.3
2550.8
6192.5
11128.3
0
115.0
152.4
262.3
397.8
0
17.8
11.2
10.3
6.4
>
\
0
2.4
8.4
.... ]
1.2
-1.7
85
-------
DETECTION _M:T
SUfKY' !,.=
SUM CO, i .' =
SUMCX^ m2=
SUM =
OPP. COEF.=
GPP. COEF.=
BEi-Tfl
— ~, ci '- *• • '-'
-55! 3223
-55.3223
-55.3223
-143.97-3
34. 0222
-105.9773
59. 0222
273.3671
16.3671
-36. 1329
103.3671
333. 5570
-176.4430
-161. 4430
75.5570
375.6266
-493. 3734
-197.3734
220. 6266
,"l -1 '•H ^ ~"
0 -> f 5 "
j r 'J L r
•-' . -.' 0 f • 0
•J. 0000
0. OOOO
0 . 0000
1 . 0000
1 . 0000
'. . 0000
1 . 0000
2 . Lj 0 0 0
2 . 0008
2. 0000
2 . 0 0 0 0
"-' . ft ft ft fi
3. 0000
3 . 0 0 0 0
: . 0000
4. 0000
4. 0000
4. 0000
4 . 0 0 o 0
215.46
N« 20.00 n=
TOTflL Ns 20.00
t» 1.73
t BfliED ON TOTflL N
UPPER CONFIDENCE LIMIT fiT>;;=0^
1.00
446.
upper confidence line or
lower confidence line at
STflNDflPD DEVIATION flT X=
PERCENT INflCCUPflCY flT X»
PERCENT IMPRECISION flT X=
MEflN FOUND flT X=
upper confidence line ot
lower confidence line at
STflNDflPD DEVIflTIQN flT .'.>
PERCENT INflCCUPftCY flT X=
PERCENT IMPPECISIfiN flT X=
MEflN FOUND flT ,:=
upper confidence line
10M«r confidence line
STflNDflPD DEVIflTI ON flT
PERCENT INflCCUPflCY flT
PEP CENT IMPPECISIfiN flT
MEflN FOUND flT "="
at
at
1*
conf ids nee 1 ;ne of. :
lO'.ier cor-f idsn--* line ?f '
ETflNDflFD DEVI flT I "IN flf "is
PErCENT INflCCUPflC'. flT .=
PE?:-MT IMPPECISION flT X=
ME" COUND flT '=
630.00
1260.00
630.00 ij
630.00 1=
630.00 13
630.00 IS
633.00 IS
IS
1260.00 1=
12*0.08 :i
1260.00 ;i
1260.00 13
1263.00 IS
IS
2520.00 1=
2520.00 1=
2520._ 00 :i
2520!00 IS
;520.00 IS
6300.00 1=
3. -jy
J.C'O
645.25
- .-. c ~. - t
i ••_' .' •!• • r *t
235.02
114.96
2.42
2903.53
-1-: y. 4 2
5304.::
:ETE:T::H _:-ir =
86
-------
APPENDIX D. TEMPERATURE RECORDS FOR LABORATORY COMPOSTS
87
-------
D-l. Laboratory Compost Temperature Records
00
*o
Date
T4 T5 T6 T7 T8 T9 R4 R5 R6 R7 R8 R9 RC1 RC2 RC3 RCA TCI TC2 TC3 TC4
10/30
10/31
11/02
11/03
11/04
11/05
11/06
11/09
11/10
11/11
11/12
11/13
11/14
11/16
11/17
11/18
11/19
52
53
52
52
53
53
53
54
53
54
54
54
53
54
53
55
54
52
53
52
53
53
53
54
55
54
55
54
55
54
54
55
56
54
52
53
52
52
53
52
53
54
53
54
54
54
53
53
53
54
54
52
53
52
52
53
52
53
55
53
54
54
54
54
54
54
55
54
52
53
52
52
53
52
53
55
53
54
54
54
53
54
54
54
52
53
52
52
53
53
53
55
54
54
54
54
54
54
54
54
54
52
53
52
53
54
54
53
55
54
55
54
54
54
54
55
55
55
52
54
53
53
54
54
55
55
54
55
55
54
56
55
55
55
54
52
54
52
52
53
52
54
55
55
55
54
54
54
54
54
55
55
53
54
53
54
54
52
54
55
54
55
55
55
54
54
55
56
55
51
53
52
53
53
53
55
55
54
54
53
54
53
53
54
54
54
52
54
53
53
54
53
54
55
54
54
54
54
55
53
54
55
54
51
54
53
53
54
53
54
56
53
54
54
54
54
54
53
55
53
51
54
53
54
54
53
55
56
53
55
55
54
54
54
54
54
53
51
53
52
52
53
52
53
54
53
53
53
54
53
54
53
54
53
51
53
53
53
55
54
54
55
53
54
55
54
54
53
54
55
54
50
53
52-
52
53
52
53
54
53
54
54
54
54
54
53
54
53
50
53
52
52
53
52
53
54
53
54
54
54
54
55
53
54
54
50
53
52
53
53
52
54
55
53
55
55
55
55
55
55
56
55
51
54
53
53
54
53
54
55
54
55
55
55
55
55
55
56
55
50
53
52
53
51
52
51
54
51
54
Vi
54
5'.
54
5.
54
S4
52
53
52
55
53
51
S3
55
54
54
54
54
54
5/,
51
55
54
T4, T7, T8. R6, R7, R8, RC2, RC3. TC3, TC4 removed for analysis. Samples selected at random.
(continued)
-------
(continued)
Date
T4
T5 T6 T7 T8 T9 R4 R5 R6 R7 R8 R9
RC1 RC2 RC3 RCA TCI TC2 TCJ TC4
11/20
11/21
11/23
11/24
11/25
11/30
12/01
12/02
12/03
12/04
12/07
12/08
12/09
12/10
59
59
59
59
58
59
59
59
59
58
58
58
57
57
54
54
54
54
54
55
55
55
55
54
54
55
54
54
54
55
55
55
55
55
56
55
59
55
55
55
55
55
55
55
55
55
54
55
55
55
55
55
55
55
54
54
58
58
58
58
58
58
58
58
58
57
57
58
57
57
56
55
54
55
55
55
55
54
54
54
53
54
53
53
55
5ft
54
54
54
54
54
54
54
54
53
53
53
53
56
55
55
55
56
55
55
55
54
54
53
53
53
53
55
54
54
54
55
55
55
55
54
54
53
54
53
53
55
54
54
54
55
55
55
54
54
54
53
53
53
53
55
54
54
54
55
54
54
54
54
54
53
53
53
53
55
55
54
54
55
54
55
54
54
54
54
53
53
53
57
57
56
56
56
57
57
57
57
57
57
56
56
Simplea extracted on 12/10. Six week* incubation.
T4-9 TNT composts
R4-9 RDX compost!
RC1-4 RDX control composts
TCI-4 TNT control composts
A-C incubator temperature readings
-------
APPENDIX E. TEMPERATURE RECORDS AND MATERIALS ADDED TO
GREENHOUSE COMPOSTS
91
-------
u
o
90
80
70
60
50
RDX
Q Replicate A
0 Replicate B
JU
2000
UJ
e
R]
U>
1000
Materials Added to Compost ES3 Replicate A
-
—
*
._
jsj
ISI
Kj
* bl 1
s
s
V
s
s
V
s
X
X
X
x
X
x
X
X
X
X
X
X
X
X
X
X
X
s
s
s
s
s
s
s
s
s
s
>
\
N,
y
s
s
X
X
x
x
X
x
X
X
X
X
X
x
X
x
X
x
X
X
K^d Replicate B
^
V
•V
N
s
S
S
s
x.
s
s
"s
\
x
^
x
X
x
X
X
x
X
x
x
x
^ ^
V X
X X
s x
"N •""
^ ^
1 ^' 1
21
RDX Compost
28
35
•'•"Sued compost or manure added
-------
TNT
u
o
80
70
60
50
30
2000
t-l
00
1000
14
TNT Compost
21
0 Replicate A
0 Replicate B
yy i
Materials
A+B B A ,
A<
^
Jded t
o
Compc
_l
)S
"
x
x
X
X
X
X
X
X
X
X
X
X
X
t
1
X
X
X
X
X
X
s
X
x
X
s,
X
s,
s
x
X
X
x
X
x
V
x
s,
s
J
^
s
s
s
s
s
s
s
^
s
^
s
*
**
s
s
f
**
s
s
s
^
^
^<3i Replicate A
E73 Replicate B
Figure E-2.
Temperature Profiles and Materials Additions for TNT Greenhouse
Composts
-------
CONTROL
vO
o
o
80
70
60
50
ui
l-i
bfl
30
1000
J\J\J\J
2000
1000
II 1 1 1 I
is
* 1
Materials Added to Control Compost
*
1
1
*
, n
1 1
21
Control Compost
•Seed compost or manure added
Figure £-3. Temperature Profile and Materials Additioi
28
35
Control Greenhouse Compost
-------
APPENDIX F. ANALYSIS OF GREENHOUSE COMPOST ATMOSPHERES
FOR OXYGEN AND CARBON DIOXIDE
97
-------
Table F-l. Average Levels of 02 and CC>2 in Greenhouse
Compost Atmospheres
% 02
% C02
Compost Composting (days) X
Control 8
14
28
31
38
TNT 8
14
28
RDX 4
11
17
28
32
39
4.7
16.8
7.4
11.8
8.6
14.4
14.0
19.3
13.6
17.5
14.9
17.3
16.5
14.1
S
4.4
3.2
4.3
0.5
0.3
4.9
0.5
<0.1
0.4
X
7.7
9.2
14.5
27.5
14.0
4.0
18.3
3.1
14.7
6.0
14.9
9.5
10.9
12.8
S
5.7
15.1
4.4
4.0
0.6
8.3
0.9
<0.1
0.8
Average Levels of 02 and CO2 in Greenhouse Compost Atmospheres
99
-------
APPENDIX G. PHOTOGRAPH OF A GREENHOUSE COMPOST
101
-------
Figure G-l. Photograph of A Greenhouse Compost
103
-------
LIST OF ABBREVIATIONS AND SYMBOLS
14C
14C-RDX
CO 2
CPM
DNT
DPM
2-amino-DNT
4-amino-DNT
g
GC
H20
H2S04
Kg
LSC
mCi
Ug
mg
mL
tiL
nnn
N"
NaOH
run
02
degrees centigrade
carbon 14; radioactive
uniformly ring labeled
uniformly ring labeled
carbon dioxide
counts per minute
dinitrotoluene
disintegrations per minute
2-amino-dinitrotoluene
4-amino-dinitrotoluene
gram
gas chromatograph
intersection of two quadratic equations for
quench correction
defines the relationship for the energy response
of a specific sample to the energy response for
an unquenched standard
water
sulfuric acid
kilogram
liquid scintillation counter
microcurie
millicurie
microgram
milligram
milliliter
microliter
millimeter
nitrogen
sodium hydroxide
nanometers
oxygen
105
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pH - hydrogen ion concentration
RDX - hexahydro-1,3,5-trinitro-1,3,5-triazine
Rf - distance traveled relative to solvent front
tetra - .tetra-nitroazoxytoluene
TLC - thin layer chromatography
2 2 sigma (95% confidence level)
UV - ultraviolet
w - week
106
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DISTRIBUTION LIST
Defense Technical Information Center
Cameron Station
Alexandria, Virginia 22314
12 copies
Defense Logistics Studies Information Exchange
Ft. Lee, Virginia 23801
2 copies
Chemical Systems Laboratory
ATTN: DRDAR-CLJ-I
Aberdeen Proving Ground, Maryland 21010
2 copies
U.S. Army Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland 21010
8 copies
107
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