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FY 2003 ABSTRACTS
EVALUATION OF CLOSTRIDIUM PERFRINGENS AS AN INDICATOR
ORGANISM TO ASSESS THE EFFICIENCY OF BIOSOLIDS DISINFECTION PROCESSES
Principal Investigators: Dr.
Christine Bean, University of New Hampshire
Problem and Research Objectives:
Domestic sewage is treated to minimize the public health risk from
pathogens in biosolids applied to land nationwide. The Environmental
Protection Agency (EPA) has published regulations, the Part 503 Rule
(EPA Part 503 Biosolids Rule), which establishes the processes and
conditions required to minimize these risks. The pathogen regulations
are intended to reduce the presence of pathogens to concentrations
that should not cause adverse health effects. Pathogen standards
include treatment requirements, site restrictions and monitoring
requirements. Pathogens of concern include bacteria, viruses, protozoa
and helminths. A complete list of principal pathogens of concern
in domestic sewage and sewage sludge considered in establishing the
Part 503 Rule is included as Appendix A.
Two categories of biosolids have been established and include Class
A, which have no detectable pathogens and Class B, which have detectable
concentrations of select pathogens. A combination of treatment and
site restrictions for Class B biosolids are intended to result in
reduction of pathogens and indicator microorganisms to undetectable
concentrations prior to public contact (Southworth 2001). Class A
biosolids are treated to reduce pathogen densities below the following
detection limits for these organisms: less than 3 most probable number
(MPN) per 4 grams of total solids for Salmonella sp.; less
than 1 plaque-forming unit (PFU) per 4 grams of total solids for
enteric viruses; and less than 1 viable Ascaris ova per
4 grams of total solids for helminths.
The routine examination for pathogens is time consuming and reliable
methods do not exist for many organisms likely to be present in biosolids
including emerging pathogens such as Microsporidia and E.
coli 0157:H7. The human pathogen Ascaris lumbricoides is
screened for when assessing the presence of viable helminth ova in
biosolids. Ascaris was chosen as the parasite indicator
organism in the 1970's when the EPA regulations were being written
since these helminth ova have a long survivability in the environment
and are easy to identify due to size. The problem with using only
this organism to assess parasitic risk is that it is not ubiquitously
present in biosolids due to a variable geographic distribution. Other
parasites like the protozoa Cryptosporidium and Giardia have
been detected in products of wastewater treatment and biosolids (Bean
and Brabants 2001b) and appear to be more prevalent than Ascaris
ova in some biosolids. Screening is not currently required for these
organisms in the Part 503 EPA regulations.
Indicator organisms are certain species of organisms believed to
indicate the presence of a larger set of pathogens that may be used
to monitor whether the larger set of pathogens may be present. Fecal
coliforms are used as indicator organisms in the Part 503 Rule to
classify Class A biosolids and therefore determine health hazards.
Fecal coliforms are also used to indicate wastewater treatment efficiency
and are measured to determine if bacteria have repopulated when Class
A biosolids are stored before land application. We have found that
fecal coliforms underestimate pathogen health hazards in experiments
performed to assess the effects of lime stabilization on biosolids
(Bean and Brabants-see Related Research section). The oocysts of Cryptosporidium
parvum are more hardy that fecal coliforms and survive longer
when treated with lime to a pH of 12 (Bean and Brabants Related Research).
Clostridium perfringens has been suggested as a better
indicator organism to assess the efficiency of biosolids disinfection
processes than screening for parasites that may or may not be present. C.
perfringens is a spore-forming bacterium and has been suggested
as a tracer for less hardy indicators and for the absence of protozoan
parasites or viruses during wastewater treatment (Payment and Franco
1993). This organism is found in densities of 10 6 colony forming
units (CFUs) per gram of solids in raw or untreated biosolids and
has been suggested as an excellent surrogate for the eggs of Ascaris (Reimers
et al. 1991) in systems including composting and anaerobic digestion. C.
perfringens spores were selected for monitoring Ascaris ova
survival in chemically processed municipal sewage sludge, because
both organisms appear to exhibit similar resistance to physical and
chemical agents.
The Part 503 regulations lack a timely method to monitor indirectly
for the inactivation of Ascaris ova and Ascaris inactivation
is used to determine whether a disinfection process produces Class
A biosolids. The direct method of assessing Ascaris ova
inactivation currently requires recovering the eggs from biosolids,
placing them in culture for 3 to 4 weeks and then examining the ova
microscopically for viability. The method is time-consuming, costly
and ova are not present in all biosolids consistently. An inexpensive,
simple technique to monitor for inactivation of helminth eggs by
surrogate microbes would be beneficial. C. perfringens may
be a good indicator organism for Ascaris inactivation by
anaerobic digestion.
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EFFECTS OF LAND USE ON WATER QUALITY IN A CHANGING LANDSCAPE
III
Principal Investigators: Dr. Jeffrey
Schloss, University of New Hampshire
Descriptors: lake, stream, water quality, nutrients, land use
Problem and Research Objectives:
The waters of New Hampshire represent a valuable water resource
contributing to the state's economic base through recreation, tourism,
and real estate revenues. Some lakes and rivers serve as current
or potential water supplies. For most residents (as indicated by
boating and fishing registrations) our waters help to insure a high
quality of life. As documented in the 2000 Census, New Hampshire
currently leads all of the New England states in the rate of new
development and redevelopment. The long-term consequences of the
resulting pressure and demands on the state's precious water resources
remain unknown. Of particular concern is the response of our waters
to increasing non-point source pollutant loadings due to watershed
development and land use activities. While in-depth watershed nutrient
budget measurements and modeling have been attempted on a small number
of watersheds scattered throughout the state, these studies represent
only short-term examinations of non-point source pollution nutrient
loading. A longer-term monitoring program conducted through differing
weather years as well as before and after changes on the landscape
occur and watershed management programs are implemented is required.
This will better document impacts of land use changes and management
efforts that have happened and to better model and predict future
impacts and successes.
The proposed investigation would allow for the improvement of predictive
models used for watershed planning and management. The benefits of
this are wide ranging from assisting watershed stewardship education
efforts throughout the state and region to providing existing watershed
based programs like the EPA Basins Model Initiative, the statewide
Unified Watershed Assessment Initiative (under the federal Clean
Water Action Program) as well as regional initiatives (US EPA Region
1 and NE states) to develop total daily maximum loading criteria
(TMDLs) and nutrient criteria for lakes, rivers and streams. The
project will also complement current efforts underway to predict
receiving water response to nutrient loading for source water protection
planning. In addition the work will provide additional data to include
in our submissions to EPA's new STORET and for use in a collaborative
web based water quality data distribution project between UNH and
the NH Department of Environmental Services.
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WATER QUALITY AND THE LANDSCAPE: LONG-TERM MONITORING OF
RAPIDLY DEVELOPING SUBURBAN WATERSHEDS
Principal Investigators: Dr.
William McDowell, University of New Hampshire
Descriptors: land use, water quality, nutrients, non-point source
pollution
Problem and Research Objectives:
New Hampshire 's surface waters are a very valuable resource, contributing
to the state's economic base through recreation (fishing, boating,
and swimming), tourism and real estate values. Many rivers and lakes
also serve as local water supplies. New Hampshire currently leads
all New England states in the rate of development and redevelopment
(2000 Census). The long-term impacts of population growth and the
associated changes in land use to New Hampshire 's surface waters
are uncertain. Of particular concern are the impacts of non-point
source pollution to the state's surface waters (e.g. septic, urban
run off, road salt application, deforestation and wetland conversion).
Long-term datasets that include year-to-year variability in precipitation,
weather patterns and other factors will allow adequate documentation
of the cumulative effects of land use change and quantification of
the effectiveness of watershed management programs.
The proposed work will continue documentation of long-term changes
to water quality in response to changing land use and management
practices resulting from population growth. There are several components
to this project, drawing from the efforts of local watershed monitoring
groups, the UNH Office of Sustainability, as well as on-going research
projects by UNH staff and students, all leading to long-term datasets
of water quality in New Hampshire. These datasets can be used to
assess the impacts of human development, land use changes and management
practices in rapidly growing areas of the state. Further, these data
could be used to test and refine water quality models and aid in
the development of best management practices and restoration efforts
across the state and region.
The proposed project will provide detailed, high-quality, long-term
datasets which will allow for a better understanding of the impacts
of land use change and development on surface water quality. This
could occur through the development, testing and refinement of predictive
models, accurately assessing the impacts of watershed management
practices, and potentially early warning of dramatic changes to surface
water quality in the region resulting from rapid development.
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