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INNOVATIVE RESEARCH FOR A SUSTAINABLE FUTURE
Study Examines the Fate of Multiple Contaminants when Biosolids are
Applied to Agricultural Land
Background:
Biosolids are solid residues
produced by wastewater that are
treated to meet federal and state
regulations for land application.
About 60% of biosolids are
applied to land as an agricultural
amendment in the United States.
Communities in all 50 states
reuse their biosolids, many for
the nutrient-rich benefits.
Anything that can be flushed
down a toilet, go down a drain in
a home or industrial facility, or
enter a storm sewer can
potentially end up in wastewater.
Chemicals such as
Pharmaceuticals and cleaning
products often used in homes are
being detected in wastewater.
Domestic wastewater also
contains bacteria and other
microbes from the digestive
tracts of humans. Appropriate
wastewater treatment methods
are designed to remove
pathogens in biosolids to safe
levels. Many chemicals are
monitored in biosolids before
land application.
In 1993 under the Clean Water
Act, the U.S. Environmental
Protection Agency (EPA) issued
regulations governing land
application of biosolids,
commonly referred to as the Part
503 Rule. In the years since the
regulations were issued,
however, wastewater treatment
technologies and practices have
changed and public concerns
about the land application of
biosolids have grown.
In 2002, the National Research
Council (NRC) of the National
Academy of Science issued a
report entitled: "Biosolids
Applied to Land: Advancing
Standards and Practices" (NRC,
2002) recommending additional
research to reduce uncertainties
about the potential for adverse
human health effects from
exposure to biosolids.
Motivated by this report and
other research questions, a
collaborative research team under
the leadership of the EPA's
Office of Research and
Development was assembled. A
field-scale land application study
was undertaken to evaluate
sampling methods and analytical
techniques.
Research Details:
A major objective of the
Biosolids study was to screen
many of the available methods
for applicability. The study
included four environmental
matrices (air, airborne
particles, soil, and biosolids),
35 analyte groups, and 13
sampling methods.
The multimedia approach and
numerous analyte-matrix
combinations used in this study
were unique in comparison with
other projects in this area of
study. Many studies focus
narrowly on a class of analytes
such as pathogens or chemicals,
or an environmental matrix such
as air or soil.
Conducting Bioaerosol
Sampling Behind Biosolids
Applicator
The sewage sludge used in this
study was anaerobically digested,
dewatered by centrifugation, and
treated with lime. Polymer was
added during sludge treatment.
This type of sludge treatment is
commonly used in wastewater
treatment plants and is likely to
produce biosolids with detectable
odors and aerosolized
particulates. These biosolids
were applied at typical rates
using a commercial spreader to a
field at the Piedmont Research
Station of the North Carolina
Department of Agriculture and
Consumer Services.
U.S. Environmental Protection Agency
Office of Research and Development (ORD), National Risk Management Research Laboratory (NRMRL)
Land Remediation and Pollution Control Division (LRPCD)
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In this study, microbial and
chemical concentrations were
measured in the air and soil
around the applied biosolids.
Microbial analyses of air samples
included indicator organisms,
bacterial pathogens, viruses, and
bacterial endotoxins. Air
samples were also analyzed for
odors, volatile compounds,
ammonia, and hydrogen sulfide
before, during and after
application. Microbial and
chemical concentrations were
determined for soil samples
before and after biosolids
application.
Some of the results of the
research, while not definitive,
were encouraging in terms of
public health impact. While in
some cases microbes were
detected, no bacterial pathogens
or viruses were detected in the air
samples collected. This study
was not able to determine
whether this result was because
microbes were absent, or present
and not detected. Approximately
20% of the soil samples
contained detectable
concentrations of enteric viruses,
Salmonella spp. and viable
helminth ova. Odors
were detected in the air after
biosolids application, but
dissipated after 4 days.
Collection of Biosolids Sample
for Headspace Analysis of
Volatile Organic Compounds
Outcomes and Impacts:
By obtaining data on the
concentrations of airborne and
soil-bound contaminants during
the application of biosolids on
land, this research along with the
research of others may lead to the
development of protocols that
can be used in future studies to
protect public health. Data gained
from this project constitute a
landmark set of simultaneous
multimedia information
associated with the application of
biosolids on land. These data
will be used to assist in the
development of method protocols
for sampling at other land sites
where biosolids are applied. This
information can also be used by
risk managers, such as those at
EPA program offices and
regions, to evaluate the benefits
and potential concerns with land
application of biosolids.
LAND RESEARCH PROGRAM
WEB SITE: www.epa.gov/nrmrl/lrpcd
CONTACTS
Richard Brenner, Technical
Inquiries. 513-569-7657, EPA/
ORD/LRPCD/SSMB
brenner.richard(@,epa. gov.
Carolyn Acheson, Technical
Inquiries. 513-569-7190, EPA/
ORD/LRPCD/SSMB
acheson.carolyn(@,epa.gov
Roger Yeardley, Communications.
513-569-7548. EPA/ ORD/ LRPCD
veardlev.roger(@,epa.gov
REFERENCES
Foote, E. A., C. M. Acheson, E. F. Earth, R.
F. Herrmann, R. C. Brenner, D. B. Harris, S.
J. Naber, R. H. Forbes, Jr., L. L. McConnell,
and P. D. Millner. Multimedia Sampling
During the Application of Biosolids on a
Land Test Site. EPA/600/R-11/020, U.S.
Environmental Protection Agency,
Washington, DC. 2011
Earth, E. F., R. F. Herrmann, T. Dahling, R.
C. Brenner, S. Wright, and P. Clarke.
Evaluation of Airborne Endotoxin
Concentrations Associated with Management
of a Crop Grown on Applied Biosolids. P.
Brent Duncan (ed.), Journal of Residuals
Science and Technology. DEStech
Publications, Inc, Lancaster, PA, 6(2):61-65,
(2009).
Acheson, C. M., R. F. Herrmann, E. Foote, S.
Naber, R. C. Brenner, T. Dahling, M. Graves,
J. Heckman, T. Strock, S. J. Stoll, J.
Tompkins, S. Vonderhaar, S. Wright, and L.
Zintek. A Study of Land Application of
Anaerobically Digested Biosolids. Presented
at the 10th Annual National Biosolids
Conference/Workshop, Potomac, MD, June
16, 2008.
National Research Council (NRC). Biosolids
Applied to Land—Advancing Standards and
Practices, The National Academies Press,
Washington, DC. 2002.
National Risk Management Research Laboratory
Land Remediation and Pollution Control Division
EPA / 600/F-12/625
December 2012
www.epa.gov/nrmrl
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