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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