PB84-210848
Development of the Volatile Organic
Sampling Train (VOST) for Use in
Determining Incinerator Efficiency
(U.S.) Industrial Environmental Research Lab.
Research Triangle Park, NC
Jun 84
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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PB 84-21084 a
EPA-600/D-84-168
June 1984
DEVELOPMENT OF THE VOLATILE ORGANIC SAMPLING TRAIN
(VOST) FOR USE IN DETERMINING INCINERATOR EFFICIENCY
by
Larry D. Johnson
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NC 27711
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TECHNICAL REPORT DATA
(ftcatc reaJ IHU/IICIIUIU on the reverse before completing)
1 REPORT NO.
EPA-600/n-f}4-168
2
4. TITLE AND SUBTITLE
Development of the Volatile Organic Sampl
(VOST) for Use in Determining Incinerate
7. AUTHORIS)
Larry D. Johnson
3. RECIPIENT'S ACCESSION NO.
5 REPORT DATE
ing Train June 1984
>r Efficiency 6- PERFORMING ORGANIZATION CODE
B. PERFORMING ORGANIZATION REPORT NO.
9 PERFORMING OPOANIZATION NAME AND ADDRESS
See Block 12.
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Labora
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
NA (Inhouse)
13. TYPE OF REPORT AND PERIOD COVERED
Published Paper; 5/84
14. SPONSORING AGENCY CODE
tory
EPA/600/13
15. SUPPLEMENTARY NOTES Author Johnson's Mail Drop is 62; his phone number is 919/541-
7943.
is. ABSTRACT Thg paper discusses the development, initial evaluation, and field applica-
tion to incinerators of a new sampling train for volatile organic species. The Volatile
Organic Sampling Train (VOST) is a simple portable device, combining Tenax and
Tenax/ char coal cartridges as collection agents. Analysis of the sorption cartridges
includes a further concentration step that permits the measurement of stack concen-
trations as low as 0.1 ng/L. The Resource Conservation and Recovery Act requires
owners or operators of hazardous waste incinerators to demonstrate that the inciner-
ator can achieve adequate destruction efficiency of certain compounds before a per-
mit is issued. Many of the compounds that are commonly of interest are of low mo-
lecular weight and volatile.
17.
KEY WORDS AND DOCUMENT ANALYSIS
1 DESCRIPTORS
Pollution Efficiency
Incinerators Toxicity
Flue Gases
Sampling
Measurement
Organic Compounds
13. DISTRIBUTION STATEMENT
Release to Public
b.lDENTIFIERS/OPEN ENDED TERMS
Pollution Control
Stationary Sources
Volatile Organic Sam-
pling Train (VOST)
Hazardous Waste
19 SECURITY CLASS I'Hia Rtporlj
Unclassified
70 SECURITY CLASS (Tha page)
Unclassified
c. COSATi 1 leltl/Group
13B 14G
06T
21B
14B
07C
21. NO. OF PAGES
17
22. PRICE
EPA Form 2220-1 (9-73|
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NOTICE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policy and
approved for publication. Mention of trade names
or commercial products does not constitute endorse-
ment or recommendation for use.
ii
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ABSTRACT
Development of the Volatile Organic Sampling Train (VOST) for Use in
Determining Incinerator Efficiency.
Larry D. Johnson, Industrial Environmental Research Laboratory, U.S.
Environmental Protection Agency, Research Triangle Park, NC 27711
The Resource Conservation and Recovery Act regulations require owners
or operators of hazardous waste incinerators to demonstrate that the
incinerator can achieve adequate destruction efficiency of certain com-
pounds before a permit is issued. Many of the compounds that are commonly
of interest are low molecular weight, volatile species.
This paper will discuss the development, initial evaluation, and field
application to incinerators of a new sampling train for volatile organic
species. The train developed, the Volatile Organic Sampling Train (VOST),
is a simple, portable device employing a combination of Tenax and Tenax/
charcoal cartridges as the collection agents. Analysis of the sorption
cartridges includes a further concentration step which permits the measure-
ment of stack concentrations as low as 0.1 ng/L.
Key Words
stack sampling, volatile organics, hazardous waste, incineration,
destruction efficiency, measurement methods development
tii
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Introduction
The development and field application of the volatile organic
sampling train (VOST) has been unusual in the high speed at which it
has progressed, as well as the difficulty of the task it addresses.
The development of the train has generated a high degree of interest
in the industrial and contractor sectors, primarily because of its
application to incinerator trial burns, but also because it fills a
void in the stack sampler's arsenal.
This paper describes the concepts behind the VOST, several stages
in the development of the train, and a summary of the current status of
the VOST technology.
Background
Although the need for an improved stack sampling procedure for
volatile organics has existed for years, the situation only became
critical in relation to hazardous waste incineration. A reference
document designed to assist in planning or review of sampling and analysis
•
programs for hazardous waste incinerators or related combustors has been
produced by EPA (1). That document recommends the Modified Method 5
(MM5) train or Source Assessment Sampling System (SASS) for collection of
organics with boiling points greater than 100°C. The sorbent breakthrough
characteristics associated with lower boiling organics make the use of
these trains inadvisable for quantitative collection of compounds boiling
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below 100°C. Early drafts of Reference 1 recommended the use of either
plastic sampling bags or glass sample bulbs for collection of these compounds.
These recommendations were based on the assumption that at least 1000 ug/g
off the material was present in the waste feed, and that the destruction
etziciency of interest was 99.99Z. In early 1982, an urgent need was identi-
fied by EPA R&D engineering programs and the Office of Solid Waste. A number of
projects had been identified where volatile principal organic hazardous con-
stituents (POHC) were of interest in waste feed at 100 ug/g concentration, and
it was necessary to characterize destruction efficiencies on the order of 99.999Z.
At such low concentrations of POHC in the stack, glass sampling bulbs are
useless, and plastic bags are only effective if combined with a concentration
technique. Although it is possible to concentrate organics collected in bags
by the use of sorbent tubes or other techniques such as cold trapping, it is
not recommended because of the following reason. There are drawbacks, difficulties,
and operational pitfalls associated with any sampling technique. When two techniques
(such as bag sampling of the source and sorbent sampling of the bag) are applied
sequentially, the problems are likely to be compounded.
Since the need for a new sampling approach was apparent, and time was
an important factor, a meeting of EPA and contractor scientists and engineers
was held in April of 1982 to discuss the problem. As a result of that meeting,
the basic concepts and train arrangement for the VOST were agreed upon.
Dasic Concepts
The schematic diagram of the VOST is shown in Figure 1. The active
elements for collection of volatile organics are the two sorbent cartridges,
although some compounds may also be collected in the condensate under certain
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circumstances. The first sorbent tube is filled with Tenax porous polymer
as the primary collection agent, while the second tube contains Tenax and
activated charcoal as an extra precaution against breakthrough of the more
volatile materials. The glass sorbent tubes are 10 cm by 1.6 cm and hold 1.6 g
of Tenax or 1 g of Tenax + 1 g of charcoal. These tubes were choen because
they were the largest of the commercially available ambient air sampling
tubes and were compatible with existing desorption equipment. Larger tubes
allow larger sample volume before breakthrough occurs. Tubes much larger
than those chosen, however, become difficult to heat desorb in an effective
manner, and would require a new desorber design.
The VOST operates at 1 L/min while the sorbent'tubes are maintained
at 20°C or less during sampling. It is important that this temperature
be maintained at all times, since higher temperaturs may cause breakthrough
of the more volatile organics. Six sets of 20 min (also 20 L) samples
are collected over a 2 hr sampling period. The first set is analyzed as a
"range finder." If adequate amounts of the material of interest are found,
then the other five sets are also analyzed in an identical manner. In
some instances only three sets of tubes are analyzed, and the others are
retained temporarily as possible backup samples. In the event that the first
analysis detects no compound of interest, the remaining five sets are desorbed
and recollected onto one Tenax tube. Subsequent analysis of that tube gives an
effective detection limit five times as low as the single set analysis.
The analysis procedure used with the VOST consists of heat desorption
of the Tenax tubes into a small water vessel, followed by EPA Method 624
analysis of the water trap. EPA Method 624 is a purge and trap procedure
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followed by gas chromatography/mass spectrometry. The water trap is
included since the Tenax cartridges are often very wet and cause problems
if desorbed directly into the gas chromatography column. Several attempts
have been made to improve this part of the procedure, but none have
succeeded as yet.
For further details concerning operation of the VOST or the associated
analysis system, see References 2, 3, and 4.
Initial Laboratory Studies
The first laboratory evaluation of the VOST system was assigned to
Midwest Research Institute. A synthetic gas generation system was constructed
which was capable of producing gas streams fortified with appropriate levels
of test compounds. The compounds chosen for evaluation were vinyl chloride,
carbon tetrachloride, trichloroethylene, and chlorobenzene. The concentration
levels tested were 0.1, 10, and 100 ug/L. A series of 10 test runs were made.
The test matrix included runs at each of the four concentration levels, repli-
cate tests at one level, blanks, and a run where the gas included HC1. The
HC1 run was included since many incinerator emissions contain this compound.
Three trains sampled the gas manifold system during each run. The average
results from three trains from the experimental series are summarized in Table 1.
The single pair data was derived from analysis of individual pairs of cartridges,
one Tenax and one Tenax/charcoal. The combined pairs data results from desorption,
recollection, and subsequent analysis of multiple pairs following the procedure
described earlier. No combined pairs experiments were carried out at the higher
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concentration levels since that mode of operation was designed for low
concentrations. The combined pairs data appears to exhibit somewhat less
deviation from the desired results, but most of the recoveries fall within
± 50Z. It is important to note that the presence of HC1 did not produce
a significant effect in the recovery levels of the organics tested. Some
of the variability in the carbon tetrachloride results is believed to be
due to blank variability which was improved for later applications by better
cleaning, storage, and handling procedures. Vinyl chloride is quite diffi-
cult to handle because of its very low boiling point, and some of the data
presented in Reference 3 indicates breakthrough of the compound at higher
concentration levels. The major conclusion from the first VOST laboratory
study was that the concept was sound and that the train and subsequent analysis
procedures were capable of producing the data for which they had been
designed. Further details of the laboratory study are presented in References
3 and 4.
Initial Field Application
Immediately upon completion of the laboratory study, Midwest Research
Institute was faced with field application of the train as part of an
engineering study for EPA's Industrial Environment Research Laboratory -
Cincinnati in support of the Office of Solid Waste. The train was repackaged
into a more compact and rugged arrangement and taken to the field. Diffi-
culties were encountered on the earliest jobs in this series, primarily
from high blanks and field contamination. These were soon brought under
control, but certainly made the point that sampling very low concentrations
of volatile organics in contaminated surroundings can be very
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difficult indeed. Severe contamination was encountered with bag samples
as well, and the conclusion is clear that adequate field blanks are just
as necessary with bag sampling as with VOST.
D'-rir»R the first series of field tests of the VOST, the equipment was
also operated at two different sampling rates, and two different total
volumes were collected. The low flow rate operation was designated "Slow
VOST" and collected 5 L of gas at 250 mL/min. The stack concentrations
obtained by the two methods compared very favorably for carbon tetrachloride,
chloroform, and tetrachloroethylene. The results for trichloroethylene
were less definitive (4). Comparability of "Slow VOST" and the original
VOST operating procedure is important because it shows that breakthrough
is generally not occurring and that the equipment may be operated successfully
in more than one mode.
Further Evaluation of the VOST
The next major project to utilize the VOST was that of emissions
testing for the incinerator ship Vulcanus II. This project is described
in References 5 and 6. The VOST used in this project employed the inside-
inside cartridge design, and was constructed for Radian Corporation (formerly
TRW Corporation), Research Triangle Park (RTF), by Nutech Corp., RTF, NC. The
inside-inside (I/I) cartridge differs from the inside-outside (I/O) cartridge
in that the ends of the glass tube are drawn down to 4.2 mm (1/4-in.) in order
to accommodate gas chromatography ferrules. During the heat desorption phase
of the analysis, purge gases travel only through the inside of the I/I cartridge
but flow over as well as through the I/O tube.
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Prior to application of the VOST to the Vulcanus II project, Radian
Corporation (formerly TRW Corporation) carried out a laboratory evaluation not
unlike that earlier performed by Midwest Research Institute. A synthetic
gas stream was generated, and sampled by the I/I style VOST. The data in
Table 2 is derived from the more detailed results given in Reference 5.
It may readily be observed that the precision, and probably the accuracy,
of this data is improved over that given in Table 1. The two reasons that
seem to best explain the improvement are that much had been learned about control
of contamination and blanks, and that perhaps the I/I design was inherently more
resistant to contamination.
At any rate, the data in Table 2 strongly supports the conclusion of the
initial laboratory study, that the VOST concept is sound and will perform
as originally intended.
The first known application of the VOST to sampling highly water soluble
compounds was carried out by EPA's Industrial Environmental Research Laboratory
at RTP. The VOST was used to sample methyl vinyl ketone and tetrahydrofuran
emissions from a pilot-scale fluidized-bed combustor. This particular VOST
was of the I/O type and was constructed for EPA by Envirodyne Engineers following
the Midwest Research Institute design. In theory, highly water 'soluble compounds
are more likely to penetrate the first sorbent cartridge and be found in either
the condensate or the second sorbent cartridge. It is necessary to perform
spiking and recovery experiments in order to determine whether the compounds
of interest may be analyzed by the purge and trap method. In the event they
are not, some other method (such as direct injection or high performance liquid
chromatography) will be necessary for analysis of the condensate.
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In the project described above, the two compounds of interest were both
quantitatively recovered by a slightly modified version of the purge procedure.
Longer purge times were used, but total volume was kept the same in order to
avo?d breaVthrough. The two compounds were found primarily on the first sorbent
cartridge in spite of their relatively high water solubility. All equipment
and procedures appeared to work well even though this was the EPA crew's first
experience with it (7).
Current Status
The VOST is now available commercially, and ownership and field experience
have become more widely spread. Most of the experience has still been with
respect to the more "popular" incineration related compounds such as those listed
in Tables 1 and 2. The general consensus from users of the train is that it
works well in the field and yields good results when used with adequate care and
precautions.
Reference 2 is now available to users of the train and those reviewing
incinerator sampling plans.
A validation program for VOST is underway and is being managed by EPA's
Environmental Monitoring Systems Laboratory at RTF. Audit gas cylinders have
been prepared and are available from the same laboratory. A number of other
VOST related research programs are near completion and should provide additional
insight into the limitations of the train.
8
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Summary
Laboratory experiments and field experience to date have led to the
following conclusions.
1. The VOST concept is sound: the train performs well in the
field and yields good results in the hands of careful and experienced
operators.
2. Sampling and analysis of low concentrations of organics in the
presence of high levels of contamination is very difficult.
Strong and well planned quality control is essential.
3. Both the I/O and I/I designs are capable of producing good results
if proper precautions are taken.
4. Sampling and analysis of water soluble organics may not be as
difficult as feared, but this area stills needs exploration.
It appears that the VOST is a generally useful and flexible piece of
equipment which will be valuable for other sources in addition to incinerators.
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TABLE 1. VOST Recovery Efficiencies, Initial Studies
Z Recovery
Expec ted ,
Combined Pairs
Single Pairs
ng/L
0.1
1.0
1.0
1.0*
0.1
1.0
1.0
1.0*
10
100
vinyl
chloride
111
48
146
79
79
63
85
95
142
43
carbon
tetrachloride
176
88
113
110
221
47
55
40
70
108
trichlorethylene
97
108
105
105
79
116
115
95
109
132
104
131
115
96
95
153
105
90
106
101
*Included HC1
10
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TABLE 2, VOST Recovery Efficiencies, Further Studies
Compound Expected Value, ng/L % Recovery
1, 1 dichlorethane 54 105
77 90
chloroform 69 147
118 98
1, 2 dichlorethane 77 95
80 98
carbon tetrachloride 73 91
74 70
trichloroethylene 67 99
96 97
1, 1, 2 trichloroethane 66 78
94 68
75 120
tetrachloroethylene 107 105
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REFERENCES
1. Harris, J.C., Larsen, D.J., Rechsteiner, C.E., and Thrun, R.E.fi
"Sampling and Analysis Methods for Hazardous Waste Combustion,"
EPA-600/8-84-002, PB84-155845, February 1984.
2. Hansen, E. M., "Protocol for the Collection and Analysis of Volatile
POHCs Using VOST," EPA-600/8-84-007, PB84-170042, March 1984.
3. Jungclaus, G. A., Gorman, P.G., Vaughn, G., Scheil, G.W., Bergman,
F.J., Johnson, L.D., and Friedman, D., "Development of a Volatile
Organic Sampling Train (VOST), " Presented at Ninth Annual Research
Symposium on Land Disposal, Incineration, and Treatment of Hazardous
Waste, Ft. Mitchell, KY, May 1983.
4. Jungclaus, G.A., Gorman, P.G., and Bergman, F.J., "Sampling and Analysis
of Incineration Effluents with the Volatile Organic Sampling Train (VOST),"
In Proceedings: National Symposium on Recent Advances in Pollutant
Monitoring of Ambient Air and Stationary Sources, Raleigh, NC, May 1983,
EPA-600/9-84-001, January 1984.
5. Ackerman, D.G., Beimer, R.G., and McGaughey, J.F., "Incineration of
Volatile Organic Compounds on the M/T VULCANUS II, TRW Inc., Energy
and Environmental Division, Redondo Beach, CA. Report to Chemical
Waste Management, Inc., Oak Brook, IL. April 1983.
6. Ackerman, D.G., McGaughey, J.F., Wagoner, D.E., and VanderVelde, G.,
"Emissions Testing Onboard the Incinerator Ship Vulcanus II Using A
Volatile Organic Sampling Train, " Presented at Symposium on Organic
Emissions from Combustion, 187th National Meeting of the American
Chemical Society, St. Louis, MO. April 1984.
7. Merrill, R.G., U.S. Environmental Protection Agency, Industrial
Environmental Research Laboratory, Research Triangle Park, personal
communication.
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Htottd Probt
Gloss Woo!
Porficulafe
Filter x
STACK
(or test System)
Isolation Valves
-Carbon Filter
••Thermocouple
Sorbent
Cartridge
Condensote
Trap Impinger
Backup
Sorbent
Cartridge
Silica Gel
Vacuum
Indicator
(y}
^=r7=p^=
\r\=f T T
Pump
Rofometer
Dry Gat
Meter
FIGURE I
SCHEMATIC OF
VOLATILE ORGANIC SAMPLING TRAIN
(VOST)
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