vc/EPA
                                    United States
                                    Environmental Protection
                                    Agency
                                   Health Effects Research
                                   Laboratory
                                   Cincinnati OH 45268
                                    Research and Development
                                   EPA-600/S1-81-028  Apr  1981
Project  Summary
                                    Aerosols  Generated  by  Liquid
                                    Sludge Application  to   Land

                                    H. J. Harding, R. E. Thomas, D. E. Johnson, and C. A. Sorber
                                      This report provides data on charac-
                                    terization of  geographically diverse
                                    digested  municipal  sludges  with
                                    respect  to  microbiological,  trace
                                    metal, pesticide, and polychlorinated
                                    biphenyl  constituents plus micro-
                                    organism levels in aerosols generated
                                    in  the  land   application  of  these
                                    sludges, utilizing  tank trucks and
                                    spray  guns.  With  a  knowledge of
                                    aerosol  levels  from  this  practice,
                                    recommendations  can be  made to
                                    reduce exposure to potentially harm-
                                    ful materials.
                                      This Project Summary was develop-
                                    ed by EPA's Health Effects Research
                                    Laboratory, Cincinnati. OH. to an-
                                    nounce key findings of the research
                                    project that is fully documented in a
                                    separate report of the same title (see
                                    Project Report information at back).
                                    Introduction
                                      Land application of human waste is
                                    an attractive waste disposal alternative
                                    to  disposal in surface waters This
                                    approach avoids contamination of the
                                    surface water supplies, returns nutri-
                                    ents to the soil, reuses the water and
                                    other wastes,  and provides additional
                                    waste  treatment.  The  policy  of the
                                    Environmental Protection Agency is to
                                    "press vigorously  for  publicly-owned
                                    treatment works to utilize land treat-
                                    ment processes to reclaim and  recycle
                                    municipal wastewater " Disposing of
                                    municipal sludge  has become a major
                                    public concern in that sludge  will be
                                    produced at municipal treatment plants
                                    in the U.S. at the rate of approximately
                                   four and one-half billion dry kilograms
                                   annualy by  the early 1980's. At the
                                   present time, municipal sludge is being
                                   disposed of  via incineration (35 per-
                                   cent), ocean disposal (1 5 percent), land-
                                   fills (25 percent), and land application
                                   (25 percent)  Incineration contributes to
                                   air  pollution  and  is  also  energy
                                   dependent.  Federal  regulations will
                                   prohibit ocean dumping of sludge after
                                   1 981 Landfill is not practical mall areas
                                   of theU.S and has potential problems in
                                   contamination  of ground  and surface
                                   waters  due  to the  concentration  of
                                   sludge in one area Land application is
                                   an  attractive  alternative  to  these
                                   processes
                                    Objectives
                                     This study was  initiated to provide
                                    information on the generation of harm-
                                    ful microbial aerosols near sites practic-
                                    ing land application of liquid municipal
                                    sludge Very little information is avail-
                                    able  regarding  the  production  of
                                    microbial  aerosols as to the types or
                                    quantities  of  organisms   produced
                                    Because  of the  importance of  land
                                    application of municipal sludges, the
                                    U S Environmental Protection Agency
                                    must collect  the  necessary data  to
                                    answer   the safety questions  If
                                    problems  are identified, then it is likely
                                    that  changes in  the mechanism  in
                                    applying  sludge can  be made  using
                                    current technology
                                     The original objective  of this study
                                    was to determine if the use of  tank
                                    trucks in applying liquid sludge to land
                                    resulted in the formation of pathogenic

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microbial  aerosols A secondary objec-
tive was to characterize the sludge from
several sites practicing land application
for the presence and levels  of micro-
biological  constituents, trace  metals,
and pesticides
   During  preliminary site evaluation,
sites  were  identified which  utilized
high-volume spray guns to apply liquid
sludge  The program objectives were
expanded  to   include  evaluation  of
aerosols generated at spray application
sites  and  to compare these results to
those from the truck sites and to sites
conducting spray application  of waste-
water.


Methods
   A preliminary screen was conducted
at six sites to characterize sludge with
regard to bacteria I and viral microorgan-
isms,  trace  metals,  organochlorme
pesticides,  and  polychlormated   bi-
phenyls (PCB's), and to evaluate each
site  for  its  suitability  for   aerosol
monitoring  Four sites were selected for
aerosol monitoring, two practicing tank
truck application and two  practicing
spray gun application From five to eight
aerosol monitoring runs were made at
each  of the four sites, and  a special
enterovirus  aerosol run was conducted
at one of the spray sites
   The preliminary screens were used to
indicate what levels  of microbiological
and chemical  constituents  could  be
routinely expected in liquid sludge  The
aerosol data  were  used to  indicate
'Whether there was  aerosolization of
microbiological  constituents  and  as
input to dispersion modeling


Conclusions
   All six sites and all  samples contained
measurable levels of cadmium, copper,
mercury,  nickel,  lead,  and  zinc  The
mean concentrations ranged from 1 5 7
/yg/g for mercury to 9,180/jg/g for zinc,
on a dry weight basis. Molybdenum was
detected in  only three samples, at con-
centrations of 40, 48, and  140/ug/g, dry
weight.
   Of the 16 priority pollutant pesticides
and seven PCS formulations screened
for in  the sludge, only chlordane and
Aroclor 1248  were  detected in any of
the samples The chlordane concentra-
tion in  sludge fell between 11 and 16
/ug/g in the four samples in which it was
detected.  Both samples from one site
(Muncie, Indiana) were found to contain
AR 1248, at 25 and  26/ug/g.
  Microbiological  screens of  sludge
samples from all sites contained four
non-enteric bacteria and eight entero-
bactena  organisms. Other organisms
were found in samples from one or more
of the sites
  Generation  of  microbiological
aerosols most likely does occur at sites
utilizing tank trucks, but results m very
low bacterial aerosol levels. Monitoring
at these sites is difficult due to the fact
that a truckload of sludge is applied over
a short penod'of time while the truck
passes over several hundred meters of
land.
  There was strong evidence for aero-
solization of microbiological organisms
at the  spray application  sites, notably
among the fecal coliforrn, fecal strepto-
cocci, and mycobactena  results  Fecal
coliforrn  and  fecal streptococci were
detected downwind at both sites, while
at Portland they were not consistently
detected at the background site and at
St. Petersburg were approximately two
orders  of magnitude lower at the back-
ground  sites Mycobactena data at St
Petersburg  gave similar results to the
fecal coliforrn data
  On a special virus run, 1,470 m3 of air
was  sampled and  no human enteric
viruses  were detected from the pooled
sample. This converts to  a concentra-
tion  of less than 0 0016 pfu/m3 of air,
and  the implication  is  that aerosol-
ization of viruses does not present  a
significant problem


Recommendations
  Where  tank  truck  application  is
exercised as  the  means of  sludge
disposal, the generation of aerosols is
likely to be minimal If further reduction
is deemed necessary, the option of sub-
surface injection should be considered
  Where spray application is the means
of disposal  certain practices may be
observed to  reduce  formation of and
exposure to aerosols, e g , creation of a
buffer zone around the application site,
application  as much as possible  under
ideal meteorological conditions, and the
use  of  low-pressure,  downward-
directed nozzles
  The   presence  of  microbiological
organisms in the sludge, as well astoxic
metals, pesticides, and polychlormated
biphenyls (PCB's),  suggests  that  the
composition  of the sludge should be
well  known before land  application is
accomplished.  In  addition to  aerosol
generation,  there  is a  potential  for
harmful effects through soil and ground
water, and there should be some assur-
ance prior to land application that levels
of these contaminants do not exceed
tolerable levels

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H. J Harding, R. E Thomas, and D. E Johnson are with the Southwest Research
  Institute, San Antonio, JX 78284, and C. A  Sorber is with the University of Texas
  at San Antonio, TX 78285
Norman E. Kowal is the EPA Project Officer (see below)
The complete report, entitled "Aerosols Generated by Liquid Sludge Application to
  Land," (Order No  PB 81-178 857, Cosf $11.00, subject to change) will be
  available only from.
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: 703-487-4650
The EPA Project Officer can be contacted at
        Health Effects Research Laboratory
        U S Environmental Protection Agency
        Cincinnati, OH 45268
    i US GOVERNMENT PRINTING OFFICE 1981 757-012/7064

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business   ..
Penalty for Private Use $300
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