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
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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.