United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600/2-79-090
August 1979
Research and Development
&EPA
Comparison of
Methods for
Sampling Bacteria at
Solid Waste
Processing Facilities
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields
The nine series are
1 Environmental Health Effects Research
2 Environmental Protection Technology
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7, Interagency Energy-Environment Research and Development
8. "Special" Reports
9 Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the pubiic through the National Technical Informa-
tion Service, Springfield, Virginia 22161
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EPA-600/2-79-090
August 1979
COMPARISON OF METHODS FOR SAMPLING BACTERIA
AT SOLID WASTE PROCESSING FACILITIES
by
P. G. Gorman
D. E. Fiscus
M. P. Schrag
L. J. Shannon
Field Programs Section
Midwest Research Institute
Kansas City, Missouri 64110
Contract No. 68-02-1871
Project Officer
Carlton C. Wiles
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommendations for use.
ii
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FOREWORD
The Environmental Protection Agency was created because of increasing pub-
lic and government concern about the dangers of pollution to the health and
welfare of the American people. Noxious air, foul water, and spoiled land are
tragic testimony to the deterioration of our natural environment. The complexity
of that environment and the interplay between its components require a concen-
trated and integrated attack on the problem.
Research and development is that necessary first step in problem solution,
and it involves defining the problem, measuring its impact, and searching for
solutions. The Municipal Environmental Research Laboratory develops new and im-
proved technology and systems for the preservation and treatment of public
drinking water supplies and to minimize the adverse economic, social, health,
and aesthetic effects of pollution. This publication is one of the products of
that research, a most vital communications link between the researcher and the
user community.
In St. Louis, the City of St. Louis, Union Electric Company, and the En-
vironmental Protection Agency first demonstrated the use of solid waste as a
supplementary fuel in coal-fired power plant boilers for generating electric-
ity. In addition to the demonstration, research tasks were conducted to evalu-
ate the relative levels of airborne bacteria and viruses at the St. Louis Ref-
use Processing Plant and other waste handling facilities for purposes of
comparison.
This report was prepared as an evaluation of the field sampling methodolo-
gies used. The total research program is fully discussed in the report, "Assess-
ment of Bacteria and Virus Emissions at a Refuse Derived Fuel Plant and Other
Waste Handling Facilities," EPA-600/2-78-152, U.S. Environmental Protection
Agency, August 1978.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
iii
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ABSTRACT
This report presents an assessment of field sampling methodologies used
to measure airborne bacteria and viruses at waste handling facilities. Dis-
cussed are the sampling methods used, the problems encountered with the meth-
odology, and the subsequent changes made to improve the methods, ASTM sub-
committee E-38.07 on Health and Safety Aspects of Resource Recovery has made
preliminary recommendations for airborne microbiological sampling in and
around waste handling and processing facilities. This report also presents
a comparative discussion of these preliminary ASTM methods.
The results showed that air filter methods such as a Hi-Vol sampler are
not generally recommended because of dessication effects of the air stream
passing over the filter. AGI 30 impinger samplers and Andersen agar plate
impactors are preferred methods. A complete discussion of the entire research
program is contained in the report entitled "Assessment of Bacteria and Virus
Emissions at a Refuse Derived Fuel Plant and Other Waste Handling Facilities,"
EPA-600/2-78-152, U.S. Environmental Protection Agency, August 1978.
This report was submitted in fulfillment of Contract No. 68-02-1871 by
Midwest Research Institute under the sponsorship of the U.S. Environmental
Protection Agency.
iv
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CONTENTS
Foreword . ill
Abstract iv
Figures vi
Tables vi
Acknowledgment vii
1. Introduction . .......... 1
2. Sampling Techniques for Aerosolized Microorganisms at
St. Louis 3
3. Comparison of St. Louis and Houston Baghouse Data 10
4. Airborne Bacterial Sampling Method Recommendations 13
5. Virus 15
References 16
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FIGURES
Number Page
1 Comparison of Hi-Vol and Andersen bacteria counts 5
2 Flow diagram of EPA mobile baghouse 6
TABLES
Number Page
1 Comparison of Impinger and Hi-Vol Sample Results at the Air
Classifier Discharge 8
2 Comparison of St. Louis RDF Plant Hi-Vol Results With Test Data
From Other Studies 8
3 Comparison of Andersen Agar Plate Results 9
4 Results of Impinger Tests for Baghouses at Houston and St. Louis. 11
vi
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ACKNOWLEDGMENT
This report was prepared by Midwest Research Institute for the Municipal
Environmental Research Laboratory, U.S. Environmental Protection Agency,
Cincinnati, Ohio, under Environmental Protection Agency Contract No. 68-02-
1871. The project officer for the Environmental Protection Agency was
Mr. Carlton C. Wiles. Its purpose is to compare the field sampling techniques
and results of work performed by Midwest Research Institute to assess airborne
bacterial and viral concentrations at solid waste handling and processing fa-
cilities. The field sampling techniques used are described in detail along
with tentative recommendations made by the ASTM E-38.07 Subcommittee on Health
and Safety Aspects of Resource Recovery. This report was written by Messrs.
P. G. Gorman, D. E. Fiscus, M. P. Schrag, and Dr. L. J. Shannon.
vii
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SECTION 1
INTRODUCTION
The energy shortage of recent years and the increasing unpopularity of
solid waste disposal via landfills have stimulated unprecedented interest in
material and energy recovery from wastes. This interest is reflected in the
large number and variety of resource recovery systems being developed. Along
with this development comes the need for evaluating such systems to identify
their potential environmental impacts and to insure that they are environ-
mentally acceptable. The required sampling and analysis procedures for evalu-
ation of these novel systems are not well developed, and several important
testing procedures are just now evolving. One such procedure is field sam-
pling for airborne bacterial and viral emissions from refuse derived fuel
(RDF) processing plants, both in the ambient atmosphere and in the air stream
from pollution control systems.
Midwest Research Institute (MRI) conducted a bacterial and viral assess-
ment at St. Louis/Union Electric (St. Louis) (1) in late 1976 and at Houston/
Browning Ferris Industries (Houston) in mid-1977 (2).
The purpose of this report is to describe critically the bacterial and
viral field sampling methodology used at St. Louis, the problems encountered
with the methodology, and subsequent changes made in the methodology for the
Houston bacterial and viral tests. Finally, the St. Louis and Houston field
sampling results are compared with each other and with data from other stud-
ies. Included also is a discussion of the tentative recommendations made by
the ASTM E-38,07 Subcommittee on Health and Safety Aspects of Resource Re-
covery (3).
Other reports concerning microbiological assessments at solid waste fa-
cilities are:
. Executive Summary - Assessment of Bacteria and Virus Emissions at a
Refuse Derived Fuel Plant and Other Waste Handling Facilities (4).
. Dust and Airborne Bacteria at Solid Waste Processing Plants (5).
. Summary Report of Laboratory Methodology Used in Measurement of Air-
borne Bacteria and Virus (6).
1
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The following sections of this report present a discussion of the perti-
nent sampling methods used at St. Louis and a comparison of results for the
different methods. Since these considerations led to modifications used in
subsequent sampling at Houston, the report presents a comparative analysis of
the St. Louis and Houston results along with appropriate comparisons with data
from other studies. These other studies are research conducted at the National
Center for Resource Recovery (NCRR) pilot plant located in Washington, D.C.
(7) and at the Richmond, California, Field Station (8). The interested reader
is also referred to work being carried out by the Department of Energy, Ames
Laboratory, located at Ames, Iowa. The Ames Laboratory currently has an on-
going study of airborne microorganisms at the City of Ames, Iowa, solid waste
recovery facility. Data have not yet been published by Ames Laboratory;
therefore, no comparative assessment of their work is included in this re-
port.
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SECTION 2
SAMPLING TECHNIQUES FOR AEROSOLIZED MICROORGANISMS AT ST. LOUIS
Tests were carried out in November and early December of 1976 to determine
relative bacterial and viral levels at the property lines and at in-plant loca-
tions for the St. Louis Refuse Processing Plant* and a number of other related
waste handling facilities.
The facilities tested were:
. A municipal incinerator
. The St. Louis Refuse Processing Plant
A wastewater treatment plant
A refuse transfer station
. A sanitary landfill
In addition to the above facilities, testing was also carried out in down-
town St. Louis. Bacterial levels were also ascertained for a refuse collection
packer truck.
Three days of testing were carried out at each of the above facilities
at the property lines (one upwind and three downwind) and at three in-plant
locations* In addition, supplemental tests were conducted at the RDF plant to
evaluatate emissions of particulate trace metals, asbestos, and microorganisms
from the air classifier system, and removal efficiency of particulates and
microorganisms by a pilot-scale mobile filter unit (baghouse).
The sampling devices used were Hi-Vol ambient air samplers, which provide
high sampling rates of approximately 19 liters/sec (40 cfm) for relatively long
The St. Louis Refuse Processing Plant was a 272 Mg/day (300 tons/day) test
facility that operated from 1972 to 1976. The plant produced RDF which was
subsequently co-fired (RDF approximately 10% of total heat input) with coal
in a steam generator by the Union Electric Company.
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periods of time (6 hr) (!) These were supplemented by Andersen agar plate
impactors with backup impingers to obtain information on the size distribution
of the bacteria-contained particles and to determine if any viruses penetrated
the impactor into the impinger. Greenburg-Smith (GS) impingers were used to sam-
ple the inlet and outlet of the pilot-scale mobile filter at St. Louis.
Hi-Vol filters used in St. Louis and at related waste handling facilities
were located at the property lines and in-plant. Those located in-plant were
equipped with precyclones to remove particles larger than 10 ^m, which would
be nonrespirable and which might overload the filters. At all of these loca-
tions, an Andersen agar plate impactor was used to determine the number of
bacteria-containing particles as a function of size.
Since both Hi-Vol and Andersen samplers were used in the St. Louis test
program, it is possible to compare results from these two sampling methods.
However, the validity of such a comparison is questionable because the sam-
pling rate for the Hi-Vol, 19 liters/sec (40 cftn), is much higher than that
for the Andersen, 0.47 liter/sec (1 cfm). More importantly, the Hi-Vol results
cover a 6-hr sampling period whereas the Andersen results cover a much shorter
period (0.5 to 10 min). Recognizing these differences, however, a comparison
of the results does illuminate some aspects of bacterial sampling and analysis,
as discussed below.
Representative results for the total bacteria count determined from the
Hi-Vol and Andersen agar plate impactor samples taken at in-plant locations
are shown in Figure 1. From this figure, it can be seen that the counts per
cubic meter were higher for the Hi-Vol samplers than for the Andersen sam-
plers. Since it was expected that substantial die-off might occur on the 6-hr
Hi-Vol samples, it was surprising that this phenomenon occurred. However,
when one considers what the data from these two types of samples represent,
the results are not so surprising.
The Andersen results actually represent viable particles, each of which
may contain several bacteria. Hi-Vol samplers also capture viable particles,
but in the analysis procedure the Hi-Vol filters are first homogenized with
distilled water in a Waring blender. It is possible that this would break up
the particles and associated numbers or colonies of bacteria, thereby result-
ing in higher counts than those obtained by the Andersen sampler even if sig-
nificant die-off had occurred on the Hi-Vol filters during sampling. Although
this explanation has not been confirmed, it is the most probable reason for
the higher counts obtained by the Hi-Vols and demonstrates how different sam-
pling and analysis procedures can yield different results.
Another interesting comparison that can be made from the St* Louis test
data relates to two types of sampling conducted at the inlet to the pilot-
scale mobile fabric filter (baghouse) tested at the RDF plant. Figure 2 is a
flow diagram of the mobile fabric filter.
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ioV
10
o
10
10
V'"
\/
s'\
Andenen Samples
A. LI A In-Plant Hi-Vol Samoles
\
t.J 1=1- * ^ <* * -
| S - ±* _J| | j J x? | 6 ?£ fiS
III ii ij i i j i 111 ] i j i j i
RDF
Plant
Wait*
Transfer
Sanitary
Landfill
Incinerator W.W.T.P.
Figure 1. Comparison of Hi-Vol and Andersen bacteria counts.
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r\
Air -RDF / \
AIR CLASSIFIER\ /
CYCLONE \ /
ry(
09
1
RDF
Sa
r
Filter Inlet
Sampling
V.
m
^-
^
er
pie
*
-^
Air Classitier
Discharge 7 ^
Sampling C. '^ ^
Location . ,
/to Atmosphere
^J 14.3Dnm3/s
3
85 mm Dia. Duct ^/Mobile Trailer
.x _^
J> Air Exhaust i
to Atmosphere !
0.052Dnm3/s |
TT-TIT ^y ^ssi\>
__ j j'j'-^FabricX ] Filter
EPA MOBILE
BAG HO USE
r
\ /
Collected
Particulate
Filter Outlet
Sampling
Location
Operation: EPA bag filter draws a portion of the Air Classifier
Cyclone exhaust from the 1.07 m dia. duct. This
air sample is passed continuously through the fabric
filter to determine filter efficiency.
Figure 2. Flow diagram of EPA mobile baghouse.
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Hi-Vol sampling was carried out at the discharge of the air classifier
system to determine particulate loading, and samples of the material collected
were analyzed for bacteria. This sampling was done at a rate of about 4.7
liters/sec (10 cfm) for approximately 30 min. This sampling was done during
the 6-hr period that impinger sampling was also being conducted at the inlet
of the mobile baghouse. The latter sampling used a modified GS impinger fol-
lowed by a standard GS impinger, both of which contained Hanks balanced salt
solution (sampling rate, 0.47 liter/sec). Thus, it is possible to compare re-
sults from both these sampling techniques as shown in Table 1. Data in this
table show that higher counts were obtained from the impinger sampler and may
be indicative of increased die-off on the Hi-Vol filters. This die-off rate
ranges from 90 to 97%.
In-plant samples taken with the 6-hr Hi-Vols at the St. Louis PDF plant
can be compared with results from other studies at the NCRR pilot plant lo-
cated in Washington, D.C., and the Richmond, California, Field Station. Such
a comparison, using representative data, is shown in Table 2. The St. Louis
data are based on 6-hr Hi-Vol results whereas the NCRR data (7) are from a
Sierra cascade impactor in which paper filter substrates were used. This tech-
nique used a low sampling rate of 0.35 liter/sec (0.75 cfm) covering a period
of approximately 30 min. Richmond Field Station data (8) were obtained from im-
pinger samplers with nutrient broth (sampling rate and time not specified).
Examination of these data, which represent different sampling techniques at
different resource recovery plants, shows that the impinger sampling gave
higher counts for fecal Streptococcus, total coliforn, and fecal coliform,
whereas the 6-hr Hi-Vols gave much lower counts. Again, this may indicate
the detrimental effect of long sampling periods (i.e., 6 hr).
It is interesting to note in Table 2 that all three sampling methods
showed higher counts for fecal Streptococci than for total coliform or fecal
coliform. This supports Peterson's (9) recommendation that alpha hemolytic
Streptococcus be used as the indicator of upper respiratory pathogens in air
samples from solid waste processing. This organism is usually considered to
be human-borne and present in the upper respiratory tract of all normal in-
dividuals. Further, it is an easily recognized organism and survives well in
air.
At least three studies, including the one at St. Louis, have been carried
out at waste processing facilities using the Andersen agar plate impactor. A
comparison of the results from these three studies, given in Table 3, shows
fairly similar results.
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TABLE 1. COMPARISON OF IMPINGER AND HI-VOL SAMPLE
RESULTS AT THE AIR CLASSIFIER DISCHARGE
Concentrations in councs/m
Fecal
Total counc Total coliform Fecal eoliform Streptococci
Irapinger sample 5.25 x 108 3.36 x 106 4.62 x 105 2.25 x 10
Hi-Vol sample 0.12 x 108 > 0.07 x 106 0.28 x 105 0.22 x 106
TABLE 2. COMPARISON OF ST. LOUIS RDF PLANT HI-VOL RESULTS WITH
TEST DATA FROM OTHER STUDIES
_ In-plant bacteria concentrations (counts/m3)
Fecal
Location Total count Streptococci Total coliform Fecal coliform
NCRS, Washington, D.C.,
pilot plant (7)
Location b2/ 282,000 11,000 1,900 92
Location c£f > 1,336,000 > 14,800 1,200 20
St. Louis (1)^ 4,000-1,630,000 10-478 < l-> 213 <1-30
Richmond, California, 4, 700- 12,700£'' 14,000- 19, 000^/ 2,200-3,900d/ 140-2, 400^
Field Station (8)
il Test data for NCRR are from two test locations ia-plant, taken when the plant was
operating and samples were not stored overnight. Counts shown are total of all
stages of a Sierra impactor, representing particles < 10 yira.
b/ Test data for St. Louis are ranges for in-plant samples, taken with Hi-Vol sam-
plers equipped with a precyclone for removal of particles > 10 nm.
cl Test data for the Richmond Field Station for total count only are based on sampling
with two different impactors (Reynier and Andersen) and three different agars (nu-
trient agar, plate count agar, and trypticase soy agar).
d/ Test data for the Richmond Field Station for fecal Streptococci, total coliform,
and fecal coliform are based on sampling with impingers (.431) containing nutrient
broth. Total count was not determined using impingers.
8
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TABLE 3. COMPARISON OF ANDERSEN AGAR PLATE RESULTS
In-plant
Test location Total count/m3
Richmond Field Station (8) 11,000-12,700
St. Louis RDF plant (1) 2,075-20,060
Six municipal incinerators (9) 140-27,900
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SECTION 3
COMPARISON OF ST. LOUIS AND HOUSTON BAGHOUSE DATA
Testing of baghouses for removal of bacteria has been carried out by MRI
at two locations as described in References (1) and (2). Both sampling methods
used involved impingers, but with some differences.
Sampling of a pilot-scale baghouse at the St. Louis plant consisted of
the following setup. At the inlet, two GS impingers, both containing Hanks'
balanced salt solution, were connected in series, but the first was a modified
GS impinger intended for capture of large particles that might plug the nozzle
in the standard GS impinger. At the outlet, only one standard GS impinger was
used. Both the inlet and outlet impingers were operated for 6 hr at a flow rate
of 0.47 liter/sec (1.0 cfm).
Later, prior to preparations for the sampling at Houston, a review of the
literature indicated that the use of an AGI-30 impinger would be a preferable
sampling technique because, unlike the GS impingers, the PCI-30 impingers are
designed for microbial sampling. Also, it was determined that gelatin milk
would be a more suitable medium for use in the impingers and that sampling
time should be reduced to 30 min to decrease the detrimental effect of air
on the organisms of interest. Again, however, it was necessary to precede the
AGI-30 impinger used on the inlet with a modified GS impinger (containing no
solutions) in order to remove any larger particles that would have plugged
the small nozzle in the AGI impinger. In sampling airborne microorganisms,
May (10) had also used a "pre-impinger" ahead of an impinger to obtain parti-
cle size segregation. No analysis was performed on the catch in the GS impinger
in the initial tests at Houston, because it was assumed this would not signifi-
cantly affect the expected high bacterial concentrations. However, the data ob-
tained proved this assumption to be erroneous. The inital results showed lower
bacterial concentrations at the inlet of the baghouse than at the outlet.
Therefore, in subsequent testing, the GS impinger catch was rinsed out and an-
alyzed; and it showed concentrations of two to three orders of magnitude higher
than the catch from the AGI-30 impinger alone. This in itself indicates that
most of the bacteria are associated with larger particles.
Based on the second set of tests at Houston, a comparison can be made of
the inlet and outlet results in Houston and St. Louis, respectively, as given
in Table 4. As can be seen in this table, the inlet particulate concentration
10
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TABLE 4. RESULTS OF IMPINGER TESTS FOR BAGHOUSES AT HOUSTON AND ST. LOUIS
Bacteria counts/m-* ~
Average Fecal
particulate concentration Total counts Streptococci Total coiiforrn Fecal coliform
Inlet
b/
Houston" ,
b/
St. Louis-
Outlet
b/
HoustoiT* ,
St. Louis
3
23.0 g/Nm
0.3 g/Nm
0.003 y/Nm3
0.00015 g/Nm
6
0.9-75.6 x 10
525 x 106
A
1.9-68.2 x 10
210 x 10
r /
2.5-361 x 10^ 0.4->455 x 10
22 x 10 336 x 10
-.
4.5-95.5 x 10 < 91-5, 000
2.1 x 10 357
4
0.4- > 455 x 10
46 x 10
<91-3,180
230
_a/ liupinger samples from St. Louis and Houston were also analyzed for SLaphylococci, Klebsiella sp. and
Salmonella, but all were very low or below detectable limits.
b/ Bacterial concentrations shown for Houston are ranges for six 30-min samples taken at a flow rate of
0.08 liter/sec (0.18 cfm), whereas only one sample was obtained from St. Louis, representing one 6-hr
test at a sampling rate of 0.47 liter/sec (1.0 ciia).
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at Houston was much higher than that at St. Louis, as expected* Also, the out-
let concentration at Houston was higher. Considering this, it is somewhat sur-
prising that the inlet and outlet concentrations of fecal Streptococci, total
coliform, and fecal coliform obtained from the one 6-hr sample at St. Louis
are generally within the range of values obtained at Houston. Even more sur-
prising is the finding that the total counts at St. Louis were higher than the
highest value obtained at Houston for both the inlet and the outlet, even
though the particulate concentrations were much lower at St. Louis. It is not
known whether this was due to the fact that these are different plants, or due
to the differences in the bacterial sampling methods.
12
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SECTION 4
AIRBORNE BACTERIAL SAMPLING METHOD RECOMMENDATIONS
Results from the St. Louis and Houston tests and other test data men-
tioned earlier have provided information from which test method recommenda-
tions have been prepared by the ASTM E-38.07 Subcommittee on Health and Safety
Aspects of Resource Recovery (3).
Andersen agar plate impactors for determinations of viable particles
counts by size were used at both St. Louis and Houston and also in several
other studies. MRI would therefore concur with ASTM's E-38.07 preliminary
recommendations that this method be used for that purpose. This ASTM subcom-
mittee also recommends that:
. A preseparator be used where dust levels are high
. Trypticase soy agar be used for total counts, with mycostatin to in-
inhibit fungal growth
. Vogel-Johnson agar be used for Staphyococcus aureus Pyogenes var.
Litman Oxgall be used for fungal counts, with streptomycin to inhibit
bacterial growth
. Levine Eosin methylene blue be used for enterics
Also, as pointed out by E-38-.07, the Andersen impactor gives data on the
number of particles containing viable cells rather than the number of cells
themselves. To an extent this is true of all methods but is more prevalent with
the Andersen impactor because it is not designed for dispersing the sample.
For determination of bacteria, irrespective of size, sampling was carried
out at St. Louis using a Hi-Vol method. For source sampling, impinger samplers
were used at St. Louis and Houston; and in one case at St. Louis, this was sup-
plemented with Hi-Vol sampling. Results from the latter, as discussed earlier,
indicated considerably lower values for the Hi-Vol method. Therefore, MRI con-
curs with E-38.07 that filter methods are not generally recommended because
of the dessication effects of the airstream. Alternatively, it is recommended
that impinger samplers be used. Since AGI-30 impingers are designed for
13
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microbial sampling, MRI's judgment at this time is that these would be the
preferred sampler.
The AGI-30 impinger samplers would also be recommended for testing of
source emissions; but where large particles are being emitted by the source,
several complications arise. First, traversing of the duct may be necessary
along with isokinetic sampling. This raises several problems because the size
of the sampling probe nozzle must be large in order not to become plugged with
the large particles, and this in turn requires a high sampling rate, above the
capability of impingers. A smaller probe could be used with lower sampling
rates, but this might require constant attention to the monitoring of the
rates, quickly backflushing the probe with air whenever pluggage occurs. This
procedure would allow use of the AGI-30 impingers and is probably the best
method that can be recommended at this time for sampling source emissions con-
taining large particles.
AGI-30 impingers are suited to ambient or in-plant sampling, and sampling
time should be approximately 30 min. Further, E-38.07 recommends that:
. Lactose broth be used for bacterial sampling
. Samples be cooled in ice immediately after being taken.
It must be pointed out, however, that the AGI-30 impingers operate at a
relatively low sampling rate and should probably not be operated for periods
exceeding 30 min. If longer periods need to be sampled (e.g., 6 hr), a propor-
tionately greater number of samples would be produced for analysis. It is pos-
sible, however, that impinger samples could be combined. Also, as mentioned
earlier, the nozzle in AGI-30 impingers is quite small and might become
plugged, especially during in-plant sampling. If large particles are removed
by physical means, such as a preseparator or preimpinger, the actual microbial
concentrations will be decreased as the large particles may harbour adsorbed
microbes. Therefore, the sampling period should not be extended beyond 30 min,
and any material collected in a preseparator or preimpinger should be analyzed
for microorganisms.
14
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SECTION 5
VIRUS
Samples taken at St. Louis and Houston were analyzed for viruses, but none
were found.
Dr. Peterson (11) has reported average viral concentrations in municipal
solid waste (MSW) of 0.32 pfu/g. If one assumes that particles of MSW are sus-
pended in air at a relatively high concentration, on the order of 1,000 ^g/ra-^,
it can be calculated that the suspended viral concentrations would be only
0.00032 pfu/m . Thus, one would have to sample over 3,000 ur of air to capture
one virus, if the virus remained viable. This quantity is far beyond the prac-
tical limits for impingers or Hi-Vbls. The reason no viruses were found during
the St. Louis and Houston testing could well be an insufficient amount of air
was sampled to yield a probability of finding a virus.
Therefore, MRI cannot recommend any suitable sampling technique for
viruses; and perhaps there is no need for such a method if the concentrations
are as low as the above calculations would indicate, based on the results re-
ported by Dr. Peterson (11)
15
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REFERENCES
1. Assessment of Bacteria and Virus Emissions at a Refuse Derived Fuel Plant
and Other Waste Handling Facilities* Report prepared by Midwest Research
Institute for the U.S. Environmental Protection Agency, Report No. EPA
600/2-78-152, August 1978.
2. Evaluation of Fabric Filter Performance at Browning Ferris Industries/
Raytheon Service Company Resource Recovery Plant, Houston, Texas. Draft
report prepared by Midwest Research Institute for Municipal Environmental
Research Laboratory, Office of R&D, U.S. Environmental Protection Agency,
Cincinnati, Ohio, EPA Contract No. 68-02-2166, September 1977.
3. Memorandum Outline of Sampling Procedure. ASTM 38.07 Committee on Microbio-
logical Aerosol Sampling (1978).
4. Executive Summary - Assessment of Bacteria and Virus Emissions at a Refuse
Derived Fuel Plant and Other Waste Handling Facilities. Report prepared by
Midwest Research Institute for Municipal Environmental Research Laboratory,
Office of R&D, U.S. Environmental Protection Agency, Cincinnati, Ohio, EPA
Contract No. 68-02-1871, September 22, 1978.
5. Dust and Airborne Bacteria at Solid Waste Processing Plants. Report pre-
pared by Midwest Research Institute for Municipal Environmental Research
Laboratory, Office of R&D, U.S. Environmental Protection Agency, Cincinnati,
Ohio, EPA Contract No. 68-02-1871, September 5, 1978.
6. Comparative Assessment of Bacterial and Viral Laboratory Analysis Methods*
Report prepared by Midwest Research Insitute for Municipal Environmental
Laboratory, Office of R&D, U.S. Environmental Protection Agency, Cincinnati,
Ohio, EPA Contract No. 68-02-1871, October 30, 1978.
7. Duckett, E. J. Microbiological Analysis of Dusts at the Equipment Test and
Evaluation Facility. National Center for Resource Recovery, Inc. Washington,
D.C., January 1978.
8* Diaz, L. F., L. Riley, G. Savage, G. J* Trezek. Health Aspect Considerations
Associated with Resource Recovery. Compost Science, Summer 1976.
16
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9. Peterson, M. L. Pathogens Associated with Solid Waste Processing - A
Progress Report. U.S. Environmental Protection Agency, 1971.
10. May, K. R., and H. A. Druett. The Pre-Impinger, A Selective Aerosol Sam-
pler. British Journal of Industrial Medicine, Vol. 10, pp. 142-151, 1953,
11. Peterson, M. The Occurrence and Survival of Viruses in Municipal Waste.
Ph.D. Thesis, Environmental Health Science, University of Michigan, 1971,
17
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TECHNICAL REPORT DATA
/Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-79-090
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE ANDSUBTITLE
COMPARISON OF METHODS FOR SAMPLING BACTERIA AT
SOLID WASTE PROCESSING FACILITIES
5. REPORT DATE
August 1979 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
P. G. Gorman, D. E. Fiscus, M. P. Schrag
and L. J. Shannon
8. PERFORMING ORGANIZATION REPORT NO
MRI Project No. 4033-L
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
425 Volker Boulevard
Kansas City, Missouri 64110
10. PROGRAM ELEMENT NO.
1NE624, SOS WF, Task 6.1
11. CONTRACT/GRANT NO.
68-02-1871
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Sampling Methods
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
See also EPA-600/2-78-152 and EPA-600/2-79-131.
Project Officer: Carlton C. Wiles 513/684-7881.
16. ABSTRACT "~ '~~~-~~~
This report is an assessment of the field sampling methodologies used to measure
concentrations of airborne bacteria and viruses in and around waste handling and
processing facilities.
The sampling methods are discussed as well as the problems encountered and sub-
sequent changes made to improve the methods. Comparisons are also made to preliminary
recommendations from ASTM subcommittee E-38.07 on Health and Safety Aspects of
Resource Recovery plants.
The results showed air filter methods such as a Hi-Vol sampler are not generally
recommended because of dessication effects of the air stream passing over the filter*
AGI-30 impingers and Andersen agar plate impactors are preferred methods. The com-
plete tests are fully reported in the final report, "Assessment of Bacteria and Virus
Emissions at a Refuse Derived Fuel Plant and Other Waste Handling Facilities," EPA
600/2-78-152, U.S. Environmental Protection Agency, August 1978.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Bacteria
Viruses
Mi croorgani sms
Wastes
Refuse disposal
Air pollution
Refuse derived fuels
Waste as energy
Resource recovery
Air emissions
Pollution control
Ambient air
Particulates
Baghouse
13B
. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
26
20. SECURITY CLASS (Thispage}
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
18
-- US GOVERNMENT PRINTING OFFICE: 1979 -657-060/5441
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