Natural Science Seminar - Abstracts Fall 2006
Rebecca Worley
Sept. 11, 2006
Fuel loads, tree
community structure, and carbon storage in
Mountain Longleaf Pine stands undergoing restoration.
Abstract. Longleaf pine
(Pinus palustris), once a dominant tree species in southern forest
lands, has been reduced in range from 37 million ha historically to
less than 1.2 million ha today due in large part to the removal of fire
from the ecosystem. Healthy longleaf ecosystems are characterized
by an open under-story dominated by fire-resistant grasses and widely
spaced trees. Current longleaf stands are found mostly in the
costal plain region but a few tracts remain on south-facing slopes in
mountainous regions of Alabama and Georgia. Little research
exists on montane longleaf systems and the majority of what is known is
based on data from degraded stands. The Berry College Longleaf
Restoration Project began in 1999 with the goal of restoring a
fire-maintained longleaf ecosystem to parts of Lavender
Mountain. Since that time, restoration burns and hardwood
control have been initiated in mature stands, and tree planting has
been initiated in clear- and selective-cut areas. The goals of
this project were to assess changes in the tree community structure and
fuel biomass in mature stands following an April 2004 prescribed burn,
and to determine total dry biomass across all management areas. A
planar transect method was used to quantify downed woody fuels, litter,
herbs, duff, shrubs, and small trees. Large tree biomass and
community structure data were obtained using the point-centered quarter
method. An increase was seen in the importance value of longleaf
pine in most stands, while hardwoods have decreased in
importance. Increases were seen in several woody fuel
categories, litter, and small trees since prescribed fires in 2004,
although duff biomass has apparently decreased. Biomass data were
integrated across the managed area using ArcGIS resulting in an
estimated total biomass of over 15,000 tons.
Sheree
Ferrell
Sept. 11, 2006
Comparison of Tardigrade Communities from
the Anakeesta Formation and Thunderhead Sandstone.
Abstract: Tardigrades
are a distinctive phylum of micrometazoans inhabiting a very wide range
of
habitats. Several studies have focused on specific factors that may
affect the
abundance and distribution of tardigrade populations however, little is
known
about the overall ecology of tardigrades. Currently, the All Taxa
Biodiversity
Index (ATBI) is striving to locate and identify every organism within
the Great
Smoky Mountains National Park (GSMNP). Working in conjunction with Dr.
Paul
Bartels and Dr. Diane Nelson, the results of this study will contribute
to the
inventory of the Phylum Tardigrada in the park. The
focus of collection will be on the Anakeesta Formation, which
has never been sampled for tardigrades.
Rocks within the Anakeesta Formation are typically dark,
phyllitic
slates that are most famous for causing acid drainage through chemical
and physical
weathering, thus having an adverse effect on the surrounding aquatic
ecosystems. Rock moss samples were
collected from exposed Anakeesta rocks, as well as from Thunderhead
sandstone
rocks along the Chimney Tops Trail. Soil pH was also measured. Moss
samples
were processed in the lab and individual slides of tardigrades were
made and
identified. After identification, there
were 311 total specimens and 37 total species (12 species in Anakeesta
and 25
species in Sandstone). Two new species
were added to the species list for the GSMNP, Amphibolus cf
weglarske
and Murrayon stellatus. The
importance of these two species is discussed.
Statistical tests were performed on the pH values obtained as
well as
species richness estimators that were calculated using EstimateS
software. The
Chao 1 estimator and the Shannon index were used to compare the
diversity of
populations from each rock type. There was no statistical difference in
pH for
the Anakeesta samples and the Thunderhead sandstone samples; therefore,
any
differences in the populations must be due to other factors. Overall, there were almost twice as many
specimens in the sandstone samples and 17 unique species compared to
only 4
unique species in the Anakeesta samples.
There was no statistical difference between the Shannon index
values of
the two rock types. There was an extremely significant difference
between the
Chao 1 values, with the Thunderhead sandstone having a significantly
larger
value. Also, a plot of Chao 1 values as
a function of sample numbers shows an exponential curve with a higher
curve for
the Thunderhead sandstone compared to Anakeesta. Therefore, there may
be slight
differences in the communities of tardigrades on the Anakeesta
Formation and
the Thunderhead sandstone on the Chimney Tops trail.
Because the difference in Chao 1 values between rock types were
so large, it could be assumed that the Anakeesta is a poorer
environment for
tardigrades. Since the pH did not differ, there is any number of
testable
variables that could be further researched to discover the reasons for
the
differences in diversity.
Anna
Chollet
Sept. 18, 2006
Evaluation of lead
content of commercially available kale (Brassica oleracea) in Buncombe County,
North Carolina
Abstract: Humans may be
exposed to lead, a toxic heavy metal, through food contaminated by
leaded gasoline fumes, lead paint particles from older homes, and water
contaminated with lead through lead plumbing. Another route of exposure
is through heavy metal hyperaccumulating vegetables. Heavy metal
hyperaccumulating plants are those that have the ability to draw heavy
metals from soil into their roots and shoots. One of these
hyperaccumulators includes the vegetable kale (Brassica oleracea). The objective
of this study was to measure the concentration of lead in commercially
available kale in Buncombe County, North Carolina. Three bunches of
kale were selected from five different sources on five separate days
for a total of fifteen samples. Each sample was ashed in a muffler
furnace before being digested in 10% nitric acid and 30% hydrogen
peroxide. After samples dissolved, they were loaded in a Perkin-Elmer
SIMA 6000 graphite furnace atomic absorption spectrophotometer with a
series of lead standards and reagent blanks. Calibration curves were
created to calculate the concentration of each sample. The only samples
with concentrations above the limit of detection had lead
concentrations of 34.6 ppb, 38.3 ppb, and 40.0 ppb on a dry matter
basis. The Food and Agriculture Organization and the World Health
Organization established that the maximum tolerable daily intake of
lead for a human from food, water, and air is 3.5-40 mg per kg of body
mass. For an average adult (~70 kg), 53.8 kg of fresh kale with 52.0
(118.6 lbs) ppb lead would need to be consumed to reach FAO/WHO’s
maximum tolerable intake. Though lead intake should be avoided whenever
possible, the concentration of lead in these kale samples was
negligible.
Rachel Smith
September 18, 2006
Arsenic leaching
into the soil of Murphy-Oakley Park
Abstract: Arsenic (As), a
naturally occurring element in the earth, has been know to cause severe
health problems associated with chronic overexposure, such as;
hypertension, vasoconstriction, skin lesions, cancer of the lung,
throat, bladder, and skin. Chromated Copper Arsenate (CCA) is a
compound used since the 1940’s in the treatment of wood to protect
against pests. As of December 31, 2003, the Environmental
Protection Agency (EPA) ruled that no more wood could be treated with
CCA. The EPA set a safe level of As in soil of Region 4
(including North Carolina) at 20 ppm for residential areas. Since
1995 Asheville has been replacing CCA-treated wood structures on their
school playgrounds. However, no effort has been seen to replace
the structures on the Asheville city playgrounds. The objective
of this study was to determine: if As is in the wood of certain play
structures in Asheville city playgrounds; if the As leached into the
surrounding soil; and if the levels in the soil are dangerous to the
children who use the playground. Wood from four different
playgrounds was tested for As. Only one was found to have As, the
sandbox at Murphy-Oakley Park. Samples were taken on four sides
on the inside and the outside of the sandbox right against the wood at
depths of 5cm and 10 cm, and then at 10cm away at the same depths (5cm
and 10cm). The samples were processed using EPA SW-846 Method
3040B for digestion of soils. The samples were then analyzed
using the Graphite Furnace Atomic Absorption Spectrometer.
Arsenic was found in almost all of the samples tested. All of the
inside sample groups and the sample group on the outside 10cm away x
5cm deep contained less than 20ppm with p-values of <0.001 so the
null hypothesis was rejected. Both outside sample groups at 0cm
away, 5cm deep and 10cm deep, and the outside 10cm away and 10cm deep
had p-values greater than 0.05 so the null hypothesis could not be
rejected. When inside and outside values were compared 0cm away x
5cm deep, 10cm away x 10cm deep were both considered significantly
difference with a p-value of <0.05. The other two groups (0cm
away x 10 cm deep, 10cm away x 5cm deep) were not considered
significantly different with a p-value of >0.05. With only one
sampling site this study cannot be expanded to the Asheville
area. These data support that As is leaching out of the wood into
the soils surrounding the sandbox. Further research should be
conducted on other playgrounds in the Asheville area to find
CCA-treated wood play structures and remove them if the soil levels are
too high.
Sarah
Rawleigh
September 25, 20006
Homemade and
Conventional Sprays as Aphid Control on Lettuce
Abstract: The green
peach aphid is generally widespread in the spring and is often found on
the
undersides of lettuce. An aphid feeds on lettuce by inserting its beak
and
sucking sap from the plant’s tissues. The lettuce then shows signs of
wilt and
is more susceptible to disease. Aphids are a major pest in the Warren
Wilson
College garden greenhouse. The garden follows organic certification
standards
in its pesticide use. For the past three years they have used Safer
insecticidal soap and homemade garlic spray. The purpose of this study
was to
compare the effectiveness of two homemade sprays, garlic and habanero,
to the
conventional Safer soap. Romaine head lettuce was used for this study
and was
seeded in the garden greenhouse. The lettuce was spaced apart evenly
and the
three treatments and control were assigned randomly. Aphids were
counted using
the scouting method before and after spraying. Sprays were conducted
twice. An
ANOVA test comparing the mean number of aphids after the first spray
showed no
significant difference at a p value of 0.9379. An ANOVA test comparing
the mean
number of aphids after the second spray showed a significant difference
at a p
value of 0.0004. Paired t-tests compared the mean number of aphids
present in
each treatment before and after spray two. Only the Safer spray showed
a
significant difference between the number of aphids present before
spray two
and the number of aphids present afterwards. An ANOVA test comparing
the
difference between the final and first aphid count for each treatment
showed
significant results at a p value of 0.0001. While the garlic and safer
sprays
were not significantly different in any of the ANOVA tests, Safer soap
on average
had a greater affect on aphids. Garlic spray showed promising results
while
aphid populations in the habanero and control groups increased through
the
study. The habanero spray may have been applied inconsistently
resulting in
some leaves crowded with lettuce while others looked burned. A more
concentrated and more frequently applied garlic spray may have produced
more
effective results. Future studies on aphids at Warren Wilson College
could
include observing the effectiveness of different concentrations of
garlic spray
along with the introduction of beneficial insects.
Daniel
Sockwell
September 25, 2006
A Study in the
Evolution of Viviparity Using 3-beta-HSD in Mabuya brachypoda as a Marker
Abstract: Scientists
have been studying the evolution of viviparity, or live birth, in
lizards for
decades. Oviparity is when the egg
develops outside of the mother and viviparity is when the egg
completely
develops inside of the uterus. One of
the main changes that distinguished viviparity from oviparity was the
development
of the placenta. As oviparity begins to
change to viviparity, the placenta becomes more complex and the
eggshell and
egg yolk become smaller. The M.
brachypoda lizard, a small viviparous grass skink found from
southern
Mexico to Costa Rica, has one of the most advanced non-mammalian
placentas and
exhibits traits found in only the most sophisticated viviparous lizards. The evolution of the placenta led to the
retention of the egg. Retention of the
egg in the body during pregnancy is mediated by progesterone. Hence, the presence of absence of
progesterone is a key aspect of viviparity.
My project this summer dealt with cloning 3-beta-hydroxysteriod
dehydrogenase, which is the key enzyme involved with the production of
progesterone. If the 3-β-HSD gene could
be cloned from the placenta of the lizard, it would provide evidence
for an
endocrine, or hormone producing placenta.
An endocrine placenta has not been discovered outside of mammals. The M. brachypoda is one of the most
advanced viviparous lizards known and finding evidence for an endocrine
placenta would be a huge step towards understanding the evolution of
viviparity
in lizards
Alexander K Dietz
October 9, 2006
Presence and activity of Canis latrans at Warren Wilson
College
Abstract: The coyote (Canis latrans)
is a
recent arrival to this area of the country, being native to the
American
southwest, and having expanded to unprecedented numbers and range in
the past
century. Within the past few years, a
coyote population has become firmly established on the Warren Wilson
College
campus. This study had three
objectives: (1) to determine the origins of the Warren Wilson coyote
population
in terms of the species’ natural history and spread from its native
region, (2)
to determine main areas of coyotes’ range in the immediate vicinity of
central
campus, and (3) to assess those areas in terms of habitat for the
coyote
population. The coyote’s natural
history was investigated via an extensive literature search and
interviews. In order to determine areas
of high use, two rounds of ‘All-l’ e-mails were sent out to the campus
community during the Spring and Fall semesters of 2005 soliciting
reports of
sightings. Responses from these were
compiled and applied to a GIS map of the campus to assess clusters of
frequent
sightings. Four sites were selected
from this map based upon high concentrations of sightings and assessed
for
habitat quality using aerial maps and a campus-wide land management
plan. The coyote is an extremely adaptable
species, and has managed to spread from its original fragmented habitat
into
the territories and niches left vacant by declining wolf populations. Reports from campus residents showed notable
clusters of activity in the Suicide Ridge forest stand, the Jensen
forest
stand, the Sawmill and Back Bottom pastures and river trail, and the
wildlife
pond and the Charlie’s and S-Field pastures.
All four identified areas feature abundant water sources,
including the
Swannanoa River, the swim pond, and the wildlife pond.
In addition, these areas are all rich in
small wildlife. The areas of campus
where coyotes are most frequently sighted and heard all have similar
appeal as
coyote habitat. Each has one or more
sources of water and thriving small animal populations to provide food. The New Pond and Suicide Ridge areas have
habitat ideal for denning. The Suicide
Ridge area has only one source of water over a very large range, making
it
theoretically less appealing as habitat.
One possible explanation for its popularity is that it provides
a
corridor between Warren Wilson, with the river and den sites, and the
Chemtronix site, which is appealing for being greatly isolated from
humans, and
is known to attract unusually high densities of bears.
There have been no reports of harmful
infringement of coyotes into central campus, though there have been
several
incidences of individual being frightened by individuals or groups. The coyote habitats around campus are all
relatively stable, and so long as food and water remain abundant, there
is no
reason to expect further intrusions at this time.
Meghan Cole
November 13, 2006
The Effect of
Planting Date on the Development and Yield of Lettuce (Latuca sativa)
Biodynamic farmers use many practices designed to improve yields and
crop quality through use of the effects of the planets and the full
moon on crop development. Biodynamic gardener, Maria Thun, conducted
many years of field research in an effort to optimize this practice for
use in the culture of vegetable crops. Thun concluded from this
research that the crop development differences she observed were due to
the position of the Moon in front of the zodiac constellations and
designated calendar days as root, flower, blackout, leaf or fruit type
days. Stella Natura, a calendar based upon Thun’s research,
incorporates various lunar cycles and events and provides guidance for
sowing, pruning and harvesting based upon the influences of a
particular type day. The objective of this study was to determine
whether planting date had an effect on the development and yield of
lettuce (Latuca sativa).
Ten planting dates in August 2006 were selected from the Stella Natura
calendar to test the effect of the five different type days. A
field study was conducted in the Northwest field of the Warren Wilson
College garden to determine the effect of type day on percent
germination, crop quality and total marketable yield. A growth
chamber study was also conducted to determine the effect of type day on
percent germination under controlled conditions. A two-way ANOVA
with type day and block as the main factors was conducted to test for
treatment effects. An irregular pattern of heterogeneous
treatment variances was exhibited by the data collected in the field
and growth chamber experiments. The variance of the blackout type
day treatment was significantly greater than the other type day
treatments for all of the observed crop characteristics except total
marketable yield. Because this irregularity could not be resolved
by transformation of the data, the blackout type day data were dropped
from the analysis of all treatment comparisons except total marketable
yield. A two-way ANOVA of mean percent germination in the field
(p-value=0.378), visual quality (p-value=0.661), size defect
(p-value=0.513), decay (p-value=0.088) and total yield (p-value=0.264)
showed no significant difference among the type days. In
contrast, the treatment differences in growth chamber germination were
highly significant (p=0.000), with significantly higher germination
rates observed in seed samples started on leaf and fruit days compared
to root and flower days. Type day appears to have had a
significant effect on seed germination in the growth chamber, but did
not cause a significant difference in the marketable yield and quality
of lettuce grown in the field. The observed variability of plants
seeded on blackout days in both the field and the growth chamber may
support the Stella Natura recommendation to avoid fieldwork on these
days.
Leslie Knapp
November 13, 2006
Analysis of
trimethylamine in municipal sludge treated with three cationic polymers
Abstract: Land application of
biosolids makes a cost-effective and sustainable disposal option for
many municipalities. The Blue Plains Advanced Wastewater
Treatment Plant in Washington, D.C. land applies approximately 1200 wet
tons of biosolids daily on farms throughout Virginia and
Maryland. Reduction of unpleasant odors plays a critical role in
increasing public acceptance of beneficial reuse programs.
Cationic polymers, used in sludge conditioning, are the primary source
of trimethylamine in lime-stabilized biosolids (Kim 2003). The
objective of this study was to develop a method to compare the effect
of three different cationic polymers used by Blue Plains on
trimethylamine levels in limed, gravity-thickened sludge. Ten
milliliters of gravity-thickened sludge were placed in 20 mL headspace
vials for a total of 10 vials. Polymer was added to the vial in
amounts of 0.04 grams, 0.10 grams, and 0.15 grams. The control
vial contained only gravity-thickened sludge. The polymer-sludge
mixture was blended for twenty seconds using a vortex mixer and allowed
to react for one hour. Lime (0.08 grams) was added to each vial
and mixed. Samples were immediately transported to the USDA
laboratory in Beltsville, Maryland for analysis. Solid-phase
microextraction fibers were exposed to headspace and allowed to
equilibrate for one-hour. Exposed fibers were analyzed by gas
chromatography with detection by mass spectrometry. Only one
treatment was analyzed and results were not evaluated
statistically. The gas chromatograph did produce good separation
and the coating of the solid-phase microextraction fiber was
appropriate for the absorption of trimethylamine.
Holly Alley
November 20, 2006
Endophyte Alkaloid
Levels of Tall Fescue in the Pastures at Warren Wilson College
Abstract: Tall fescue (Festuca arundinacea) is a widely
used pest-resistant cool-season grass. Fescue often harbors an
endophytic fungus, Neotyphodium
coenophialum, which enhances the vigor of the plant. The
endophyte produces two classes of toxins: loline alkaloids, which
are associated with the strength, durability and insect resistance of
the plant, and ergot alkaloids, which are associated with animal
toxicity. Previous student research has determined that Warren Wilson
College pastures are rich in endophyte. Presence of endophyte however
does not necessarily indicate level of toxin. The objective of this
study was to determine if the ergot alkaloid levels were high, medium
or low in three pastures at Warren Wilson. In September 2006, 50 grass
samples were collected from three pastures, and 0.1g of ground dry
plant tissue were obtained from each sample. A competitive ELISA test
kit manufactured by Agrinostics Ltd. was used to determine ergot
alkaloid levels. Animal toxicosis caused by ingestion of tall fescue
has been reported to occur at levels of 50mg/kg grass. The levels of
toxicity of endophyte-infected fescue were classified as high at
500mg/kg grass, medium at 250mg/kg grass, low at 80mg/kg grass and non
detectable, <50mg/kg grass. In Charlie’s pasture, 31% of
samples contained high alkaloid level, 19% of samples contained medium
levels, 13% of samples contained low levels and 37% was non-detectable.
River Bend pasture was contaminated with 47% of samples containing
medium levels and 52% non-detectable. Dogwood pasture were contaminated
with 25% of samples containing high alkaloid level, 6% medium levels,
19% low level and 50% non-detectable. Overall the levels of toxicity
detected were not excessive but are considered toxic. Because the
toxicity levels rise during warmer season, the fields with high levels
of detected toxicity should be avoided during the hottest grazing
seasons.
Drew McElwee
November 20, 2006
Lead
Concentrations in the Warren Wilson College Drinking Water Supply
Mentor: Dr. Mark Brenner
Abstract: Lead is a heavy
metal that is a health hazard at any level for all humans. Humans
are exposed to lead by inhaling air, drinking water, eating food, and
ingesting dust or dirt that contains lead. The 1986 Amendments to the
Safe Drinking Water Act (SDWA) required EPA to develop regulations to
control for lead in drinking water. The 1986 SDWA Amendments also
required that only lead-free materials be used in new plumbing and in
plumbing repairs. Solders and flux were only allowed to have 0.2% lead
content and other pipes, pipe fittings and fixtures were limited to no
more than 8% lead. EPA estimates that the average drinking water
comprises 20% of the total exposure to lead, and accounts for
approximately 240,000 cases of lead poisoning each year. The EPA action
level for lead contamination is 0.015 mg of lead per liter of water (15
ppb). In North Carolina lead exposure from drinking water is most
likely from lead present in the plumbing of the building, and not from
the local treatment plant or well. Warren Wilson College located in
Buncombe County, North Carolina has both recently constructed (after
1985) and very old buildings (before 1985). Through consolations with
the EPA, WWC staff (e.g. plumbing director) and the North Fork water
treatment plant, I determined that Warren Wilson College has never been
tested for lead concentrations in point source drinking devices
(coolers, taps, fountains). My objective was to determine the
lead concentrations in the drinking water at Warren Wilson College. The
study was conducted at WWC during the fall of 2006. Through
consultations with Warren Wilson College staff and past records of
buildings a list of water sources and plumbing installed before 1985
and after 1985 was generated. Samples were collected from a total of 8
fountains (4 pre 1985 and 4 post 1985). Samples were collected a
total of 5 times from October 20 to November 2, 2006 with at least 24
hours between sample times. For each date 2 sub samples were
collected; each source was sampled before 8 am and after 1 pm. My
method for analysis of total lead concentration followed the National
Environmental Method Index method number 3113 B using graphite furnace
atomic absorption spectrometry. The detection limit was determined to
be 0.17 ppb. Detectable levels of lead were found at 5 sample
sites ranging from 0.35 ppb to 1.6 ppb. There was no point source
drinking device that exceeded the EPA action level (15 ppb). The data
suggests that Warren Wilson College’s drinking water does not
accumulate excessive lead contamination. Future research of other
possible contaminates such as copper is recommended.
Lauren Baker
December 4, 2006
Antioxidant
Activity of Mate (Ilex
paraguariensis) and Other
Plant-Derived Beverages
Abstract: Teas, fruit juices
and wine have been recognized as having antioxidant activity. Mate tea
is an aqueous extract of the leaves of the South American holly tree, Ilex paraguariensis, and is used
culturally and medicinally in South America. Mate is a viable source of
dietary antioxidants; consumption of dietary antioxidants correlates
with reduced cancer and disease mortality. The present study was
conducted to: (1) investigate the antioxidant activity of aqueous
extracts of several commercially available brands of mate using the
quenching of the stable, commercially available
1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and (2) make a general
comparison of antioxidant activity among types of plant-derived
beverages. The DPPH assay is one of the most frequently used tools for
evaluating radical-scavenging activity of antioxidants. Five
commercially available brands of mate were analyzed and compared to the
plant-derived beverages green tea, grape juice, red wine, and
açai juice. The teas were found to have the highest average
antioxidant activity (green, 98.5; mate, 106; açai juice, 41;
grape juice, 64; red wine, 72 mg ascorbic acid equivalents/serving
beverage). Mate tea is an excellent source of antioxidants as assayed
by the DPPH method. Further studies are needed to determine the
mechanism of action of mate tea and explore its potential as a
medicinal agent.
Jessie Rowles
December 4, 2006
Effect
of Gender and Dominance on Play Behavior in Wolf Hybrids
Abstract: Wolf hybrids are
animals that have some percentage of both wolf (in this country, gray
wolf, Canis lupus) and
domesticated dog (Canis lupus
familiaris) bred into their genetic strain within the past 5
generations. This allows the term “Wolf Hybrid” to encompass any
dog containing 3%-97% wolf. Play is an integral part of the
highly social Canis family. Play is social interaction in which there
is a decrease in social distance between the interactants and no
evidence of social investigation or of antagonistic or
passive-submissive behavior during play (Bekoff 1972). The
objective of this study will be to determine if gender and dominance
status have an effect on play behavior in wolf hybrids. Nine
heterogeneous wolf dog pairs were chosen at random. Each pair was
then studied for a total of 4 hours, watching for key dominating and/or
submissive characteristics: tail position, hair bristling, ear position
and jaw licks. These characteristics were then recorded on a 10
second interval. Play behavior was watched for an additional 4
hours in the same 9 pairs, using 2 key characteristics to mark the
initiation of play; non-aggressive pawing and the play bow. The
results suggest that there is no correlation between Dominance and
play, and gender and play. Further research would have to be done
to have more decisive results due to time limits and low frequency of
interactions.
Lawson Revan
December 11, 2006
Soft Rush (Juncus effusus) as a Nitrogen Remover
in Wastewater Biofiltration for the Warren Wilson College Pig Farm
Abstract: As human activity and
agricultural development has increased in the past 50 years,
biogeochemical cycles are being affected in a way that is changing the
biosphere. Nitrogen cycling has been heavily impacted by the
agricultural industry. Fertilization, animal wastes and the
degradation of wetlands all contribute to this problem. Constructed
wetlands and biofiltration are two ways of reducing the impacts of
nitrogen rich effluent. This study observed the combined benefits
of biofiltration (efficient nitrification) and constructed wetlands
(nitrogen removal due to macrophytes) in biofilters to determine if
soft rush (Juncus effusus) has
a significant role in nitrogen removal in a biofiltration system for
wastewater of the Warren Wilson College Pig Farm. Results showed that
significantly more nitrate was removed in the biofilters with J. effusus as opposed to the
biofilters without J. effusus (p-value=0.01).
However, soft rush made no significant difference in the decrease of
ammonia in the biofilters (p-value=0.82). The implementation of
such a biofilter is recommended for the Pig Farm to decrease the risk
of nitrogen based negative implications on human and environmental
health.
Liina Laufer
December 11, 2006
Developing
Glycerin Fuel Logs
Mentor: Dr. Dean Kahl
Abstract: Declining fossil fuel
resources, air pollution, and mounting concerns about climate change
due to the release of carbon dioxide from fossil fuels have spurred the
growth of the biodiesel industry. The transesterification process
of biodiesel production creates 10% glycerin byproduct. Biodiesel
will not be economical if a market for the glycerin byproduct cannot be
found. The objectives of this study were to determine whether a
fuel log made with waste glycerin could be created that was comparable
to Duraflame® fuel logs. Several mixtures of glycerin with
sawdust, wood shavings, paraffin wax, and waxed cardboard were
examined. Several containment methods were attempted, including
milk cartons and cans. The majority of the study was
experimentation with containment methods. Thermocouple function was
inconsistent and placement of the thermocouple affected temperature
data collected. These two factors prevented the collection of
statistically analyzable results. The results that were obtained
showed that glycerin will burn when mixed with sawdust. The addition of
wax and waxed cardboard helped sustain combustion of the fuel logs
created. The burning quality was judged on temperature (when possible),
percent combustion, and a qualitative estimate of flame quality.
The experiments showed that the addition of paraffin wax or waxed
cardboard made a log that burned with a taller, hotter flame than a log
with only glycerin and shavings or sawdust. A 200 g sample of
Duraflame log burned with a mean temperature of 710°C, and a range
of 370°C-826°C. A mixture of 50 g sawdust, 25 g paraffin wax,
and 25 g glycerin burned with a mean temperature of 446°C, and a
range of 308°C-541°C. The carcinogenic gas acrolein is
released from combustion of glycerin at 290°C. At higher
temperatures acrolein will not be released; glycerin will instead form
carbon dioxide. This study showed that glycerin can be used to
create a fuel log. Further testing of various mixtures will lead
to the creation of a fuel log that could solve the problem of excess
glycerin.