Presenting Research

Students have opportunities to present research at departmental and UF wide research symposia, as well as at professional meetings such as the Soil Science Society of America.

Soil, Water and Ecosystem Sciences Department Research Forum

The Soil, Water and Ecosystem Sciences Department holds an annual Research Forum in the spring where students and faculty present about their research orally and in a poster session. The poster session includes an award for the best undergraduate student poster. See past winners and presentations from previous research forums.

• 2023 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. Claverie¹, C. and Wilkie, A.C. (2023). Biogas Energy for Remote Villages in Zambia. 20^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, February 6, 2023.

  Poster

  Abstract:

  Access to reliable energy is a major challenge for developing countries where large rural populations rely on subsistence farming and cook their food over traditional wood-burning stoves or open fires.  Women and children spend hours collecting the firewood needed for cooking, limiting time available for school/education or engaging in productive economic activities.  Cooking with wood-burning stoves is also a significant health hazard, causing illness and death due to continuous smoke and particulate inhalation.  Biogas energy from the decomposition of organic matter in an oxygen-free environment (anaerobic digestion) offers a clean-burning alternative that can be used much like propane or natural gas.  Common feedstocks for anaerobic digestion include livestock manure, food waste and crop residues.  The objective of this study was to assess the current and future potential for biogas energy in Zambia, where the electric-power grid serves only four percent of the 10.4 million mostly rural population.  The impact of biogas technology was analyzed in the context of energy use, deforestation, social and climate change effects.  The study indicates that biogas production in Zambia has the potential to provide clean energy in rural/remote areas, minimize deforestation, improve health and environmental conditions, and decrease greenhouse gas emissions.  To see the fullness of these benefits, however, policies are needed to create a market for bioenergy, transfer knowledge from experts to villagers, and promote the use of local materials for digester construction.

  2. Iyamu², C. and Wilkie, A.C. (2023). Soil Health and Compost Education for Elementary School Students. 20^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, February 6, 2023.

  Poster

  Abstract:

  Food waste deposited in landfills has negative impacts on humans and the environment.  These effects include carbon emissions, in the form of methane, and landfill leachate from decomposition of food waste, which both exacerbate climate change and reduce soil and water quality.  In contrast, composting provides a method to manage food waste and recycle valuable nutrients to improve soil structure and fertility.  This study focused on training elementary school students on food waste reduction, recycling, and diverting food waste from the school’s cafeteria through composting.  The aim of the study was to apply science education to teach environmental responsibility and resource conservation.  Food waste from the school lunch was recycled through composting to provide soil nutrients and improve soil health, hence creating a balance in the food ecosystem.  The students sorted their food waste, plastics and paper waste into separate bins.  The food, plastics and paper waste was collected and weighed daily over a six-week summer camp.  The food and paper waste was composted using two tumbling compost units to produce a soil amendment for use in the school garden.  A compost thermometer was used daily to monitor the compost temperature.  These activities provided hands-on training and experiential learning for the students.  Results of a post-training assessment revealed that the students’ understanding of composting and its relevance for soil health and ecosystems balance was much improved.  These results illustrate the value of science education in elementary schools to solve environmental problems and encourage pro-environmental behavior.

  3. Mondell¹, C. and Wilkie, A.C. (2023). Kenaf (Hibiscus cannabinus): A Sustainable Source of Horticultural Growth Media. 20^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, February 6, 2023.

  Poster

  Abstract:

  Kenaf is an herbaceous annual, soft fiber crop that may have the potential for commercial success in the state of Florida due to the high yields that can be obtained in the state’s warm climate.  The core of the crop, usually a waste by-product created during fiber production, can be utilized as growth media for containerized plants when pulverized, exhibiting properties comparable to that of peat moss.  The commercial horticulture industry is heavily reliant on peat moss as a potting medium.  However, peat moss releases carbon emissions into the atmosphere during harvest and during transportation, making it a contributory factor to climate change. Kenaf core could act as a sustainable alternative to peat moss.  Furthermore, every part of the kenaf plant can be utilized in various industries: the fibers for papermaking, the seeds in oil production, the core as a growth media, and the leaves for livestock feed.  The versatility of this crop could make it a valuable cash crop for the southeastern United States.

  4. Muchnok¹, H. and Wilkie, A.C. (2023). Decarbonizing the Cement Industry via Algae Cultivation. 20^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, February 6, 2023.

  Poster

  Abstract:

  Concrete is an essential aspect of modern infrastructure, being a much-preferred construction material because it is long lasting and low maintenance.  Concrete is produced through the creation of a paste comprised of cement and water that is mixed with aggregates such as sand and gravel.  However, the production of one pound of cement emits 0.93 pounds of CO₂.  Thus, concrete production is a major source of CO₂ emissions and accounts for approximately 8% of global carbon emissions.  As the global demand for concrete continues to increase, it is evident that efforts must be made to reduce emissions associated with its production to mitigate climate change.  This research proposes that the cultivation of algae can be integrated into the process of cement production so as to reduce the emissions associated with concrete.  Algae uptake CO₂ through photosynthesis, having a CO₂ bio-fixation efficiency of 10-50 times higher than terrestrial plants.  Algae have the ability to capture 1.8 kg of CO₂ per kilogram of algal biomass.  Therefore, we hypothesize that, through the integration of algae cultivation and cement production, CO₂ can be effectively recycled through a closed-loop system.  Algal biomass can be cultivated using the CO₂ emitted from cement flue gas.  The cultivated algae can be harvested and used to produce methane gas (CH₄) via anaerobic digestion, which can in turn be used to power the cement plant, which will in turn produce more CO₂ to be captured through further algal cultivation.

• 2018 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. Bjorndal¹, L. and Wilkie, A.C. (2018). Sustainable Farming: Application of Solar Power for Irrigation on Small Farms.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  The movement and distribution of water is among the most important aspects of farming, and as the global population continues to increase there is a need to improve the sustainability and efficiency in this area.  Smaller farms comprise a significant part of the farmland in the United States and are even more prevalent in developing nations.  These farms often do not have elaborate irrigation systems and rely on gasoline-powered pumps.  Unfortunately, these pumps cause a significant risk of fuel spills and create a dependence on fossil fuels.  On the other hand, solar-powered appliances utilize the energy already present at farms.  Sunlight is essential for growing crops, and now we have the technology to extend the energy from the sun to also power the mechanical needs of farming.  This provides farmers with independence and the convenience of a more self-sustaining farm and would be a natural progression of sustainable and water-smart agriculture.  To facilitate this development, a mobile system for a solar-powered electric pump was designed.  The unit has a solar panel that charges a lead-acid battery which in turn powers a DC pump.  Thanks to the battery, the system can store electricity, and be used on demand similarly to fossil fuel-powered alternatives.  The unit was designed for and tested on a sprinkler irrigation system.  However, because smaller farms may have unique water systems, the solar-powered pump can also be used to transfer water between different reservoirs or enable gravitational irrigation by pumping water to an elevated storage.

  
  2. da Silva², E.B., Wilkie, A.C. and Ma, L.Q. (2018). Coupling Ethanol Extraction with Anaerobic Digestion to Remove As from As-hyperaccumulator Pteris vittate.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Abstract:

  • Arsenic (As) is toxic to plants, animals and humans. As-hyperaccumulator Pteris vittata (PV) can be used in As-contaminated soil remediation. However, disposal of the As-laden biomass might present a drawback of the phytoremediation process.
  • This study assessed As partitioning among three phases (gas, liquid and solid) during anaerobic digestion of P. vittata biomass. The biomass was first extracted with ethanol. Then, extracted biomass with and without As was digested at 35°C under anaerobic conditions for 35 d.
  • Coupling ethanol extraction with anaerobic digestion decreased As concentration in P. vittata biomass from 2,665 to 60 mg kg^-1, or by 98%. While the biomass was reduced by 64-71%, volatile solids were decreased from 94 to 15-18%.
  • As a final step, 51% of As in anaerobic digestate was recovered by As-Mg precipitation. At this level of As, P. vittata biomass can be considered safe by USEPA regulations.

  
  3. Fiestas-Nunez¹, C. and Wilkie, A.C. (2018). Soil and Water Conservation Generate Profits for Vulnerable Communities in Porto Alegre, Brazil.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  Many people do not dispose used cooking oil correctly.  It is poured down the sink most of the time, penetrating sewage systems and complicating sewage purification to return it to water bodies.  In places lacking a sewage system, the oil directly penetrates and pollutes water streams and soil.  In Porto Alegre in the South of Brazil, a female group is leading the way to recycle used cooking oil.  The group belongs to the “Ilheus Ecologicos” association which represents the vulnerable community of islanders in Ilha das Flores, Porto Alegre.  This female group encourages citizens to recycle used cooking oil by offering collection points at the stand where they sell artisanal soaps, which are made from used cooking oil and medicinal herbs. This microbusiness, based on the principles of Economia Solidaria, provides them with income to improve their livelihood (better infrastructure for their homes, access to food, to health care, etc.).  For over 12 weeks, participant observation was conducted during the soap production, and market opportunities were explored to expand sales of the artisanal soap.  Fifty customers were interviewed at the organic fair where the soap is sold and eight other organic fairs were visited.  The market study identified three more sale outlets for the artisanal soap.  This means that this environmentally-friendly microbusiness can expand, and more people will be encouraged to recycle their used cooking oil; this, in turn, will contribute to the conservation of water and soil in urban areas such as the city of Porto Alegre, Brazil.

  
  4. Hallas², J.F., Mackowiak, C. and Wilkie, A.C. (2018). Wastewater Treatment Plant Phosphorus Mass Balance Using Stella Model.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Abstract:

  Much of the struvite literature focuses on either struvite production or mitigation and the effect P removal as struvite has on external systems, such as wastewater effluent and biosolids. A P mass balance model, based on activated sludge WWTPs with aerobic digestion, was developed to determine the effect P removal as struvite may have on internal system waste stream P dynamics. A system dynamics model, STELLA V9.0 (STELLA, isee systems Inc., Lebanon, NH, US), was used to generate P mass balances using stocks, flows and transforming variables (converters) with data collected from four representative WWTPs in north Florida. The treatment capacities of the WWTPs ranged from 371-2,650 m³ wastewater d^-1.  The incoming P load to these WWTPs ranged from 2.0-17.6 kg d^-1, and the treated effluent P load ranged from 0.6-4.9 kg d^-1.  The P content of the biosolids generated by the WWTPs ranged from 1.4–5.8%.  The individual physical components of the activated sludge process were replicated in STELLA for the P mass balance.  Phosphorus removal through struvite crystallization was included in the model, using the experimentally determined struvite-P production rate or converter.  Model results demonstrated that the major effect of struvite production on internal P stocks within WWTPs was a reduction in biosolids-P.  Simple, system dynamics models may be useful tools for helping to determine the feasibility of implementing struvite-P removal as a means of reducing regulated P outflows in small WWTPs.

  
  5. Higgins¹, B. and Wilkie, A.C. (2018). Local Phycoprospecting for Filamentous Algae.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  Algae are a crop whose high reproduction rate makes them ideal as a feedstock for bioenergy via anaerobic digestion, or as nutritional supplements.  The primary benefit of algae compared to other crops is their rapid reproduction rate, which is hours instead of days or months.  Additionally, algae can be grown in a wider range of areas than traditional crops and can serve multiple functions at once.  For example, algae may be used to aid in wastewater remediation at the same time as the algal biomass is used to produce biofuels.  Algal productivity can vary greatly based on retention time, season, nutrients, temperature, and species.  Many of these factors are intrinsically tied with geographical location.  As such, this study focuses on phycoprospecting for algae in the local area, with the expectation that these algae are adapted to and well suited to local conditions.  Filamentous algae, in particular, are not commonly cultivated.  However, they show promise as an alternative to the standard cultivation of microalgae.  Filamentous algae are more easily separated from the cultivation medium in which they are grown by means of filtration and are a readily usable product.  In this study, samples of indigenous algae were collected from local sites and locations recorded via photo-metadata.  The samples were analyzed and filamentous algae genera identified via light microscopy.  The study resulted in the acquisition of local Oedogonium, Ulothrix, Hyalotheca, Mougeotia, Microspora and Spirogyra cultures that can be used for future cultivation and experimentation.

  6. Kelley¹, J., Maltais-Landry, G. and Wilkie, A.C. (2018). Carbon and Nitrogen Cycling in a Gainesville Soil Amended with Dairy- and Food-derived Composts.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  Nutrient concentrations and availability vary substantially among composts depending on the materials and processes with which they are made. Agricultural operations compost wastes, mostly animal wastes such as manures, whereas composts produced in urban areas mainly incorporate food waste, sometimes with yard waste. Our objective was to measure how different composts affect nutrient availability and cycling, in addition to potential impacts on soil fertility and health. In a laboratory incubation, we compared CO2 emissions and nitrogen mineralization rates between three dairy-derived composts (composted dairy manure, vermicompost made from dairy manure, and Black KowTM) and two food derived composts (composted food waste and EcoscrapsTM) on a soil from Gainesville, FL. Incubations were conducted at 24˚C and 30˚C for eight weeks, i.e. the annual and July mean soil temperature at the PSREU in Citra, respectively. The composted dairy manure and vermicompost had the highest CO2 emissions compared to the unamended soil. Soil nitrate increased the most with composted food waste, whereas all three dairy-derived composts resulted in a decrease of nitrate compared to the unamended soil. This suggests that N was immobilized during the incubation, which is supported by the high CO2 emissions with these amendments. Overall, the food waste compost seemed to have the highest increase in inorganic N during the eight-week incubation, suggesting a greater potential as a nutrient source than the dairy-derived composts.

  
  7. O’Connell¹, R. and Wilkie, A.C. (2018). Algae Cultivation: Growth of the Filamentous Alga Oedogonium Compared to Microalgae.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  As the planet faces depletion of its natural resources, alternative and sustainable energy sources are becoming increasingly sought after. Research on the growth of algae has revealed their potential for carbon capture to reduce greenhouse gas emissions and for conversion into a fuel source for bioenergy applications. Filamentous algae have attracted recent attention as an optimal species for cultivation due to their ease of harvest and dominance over other species. To determine the most suitable species for future biomass applications, a 1000-L open raceway pond was inoculated with the freshwater filamentous alga, Oedogonium, with the addition of CO₂.  An additional two 1000-L raceway ponds with established cultures of microalgae already receiving CO₂ were used as a comparison to the growth of Oedogonium. The pond cultures were harvested weekly to determine culture density/growth (mg VSS/L) and harvest productivity (g VSS/m²-day). After 3 weeks, Oedogonium harvest productivity exceeded both microalgal ponds at 13.7 (± 0.3) g VSS/m²-day compared to 9.3 (± 0.6) and 9.5 (± 0.5) g VSS/m²-day for the microalgae. Thus, Oedogonium could serve as a suitable species for biomass production due to its higher productivity rates when compared with microalgal growth.

  
  8. Richardson¹, S. and Wilkie, A.C. (2018). Student Compost Cooperative – Reducing UF’s Ecological Footprint.  19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  Composting is a natural decomposition process in which organic wastes decompose into a nutritious soil amendment. Nutrients in organic wastes such as food scraps (primarily fruits and vegetables), as well as shredded paper and cardboard for carbon addition, can be recovered and recycled for use in agriculture, horticulture and urban gardening. When food scraps are disposed in landfills, they produce sizable amounts of harmful methane gas because they undergo anaerobic decomposition. Composting solves this issue by allowing plenty of oxygen into the system through consistent turning, which reduces methane emissions. Not only does compost enrich the soils with organic matter and improve water retention, it also significantly reduces landfill disposal of organic waste and demand for commercial fertilizers, thereby reducing society’s reliance on fossil fuels and paving the path toward a sustainable future. The Student Compost Cooperative (SCC) is a cross-disciplinary education and outreach program established by the Soil and Water Sciences Department, UF-IFAS, that fosters sustainability and nutrient upcycling through composting and sustainable gardening. The SCC strives to popularize sustainability and composting through educational demonstrations and social media. The SCC also provides free garden plots for students at the BioEnergy and Sustainable Technology (BEST) Laboratory, and encourages them to compost their food waste and use the finished product for their own organic gardens. All students and staff are invited to participate in the SCC to make the UF campus a more sustainable community.

  
  9. Vardanyan², L., Bera, T., Inglett, K.S., O'Connor, G., Wilkie, A.C., and Reddy, K.R. (2018). Carbon forms of lignocellulosic biofuel residues. 19^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, October 15, 2018.

  Poster

  Abstract:

  Biofuel production results in vast amounts of residue that can be beneficial as a soil amendment. The objectives of this study were to determine the influence of various drying treatments of wetcake – a second-generation biofuel residue on carbon forms and perform a comparative analysis of physico-chemical properties of first (bagasse) and second (wetcake) generation lignocellulosic biofuel residues. We hypothesize that bagasse will be composed of large proportion of labile (o-alkyl) carbon whereas wetcake will have more non-labile aromatic/aryl-C.

   

• 2017 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. Higgins¹, B. and Wilkie, A.C. (2017). The Effect of Harvesting Frequency on Microalgal Cultures in Open Raceway Ponds.  18^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, November 13, 2017.

  Poster

  Abstract:

  Algae are a highly productive crop that can be utilized as a nutritional supplement or as a feedstock for bioenergy via anaerobic digestion. The major benefit of algal biomass is that it reproduces within hours rather than days or months. Many factors contribute to algal productivity including availability of light and nutrients, pH, temperature, algae species, and retention time. The objective of this study was to evaluate the effect of harvesting frequency on microalgal productivity. Microalgal polycultures were maintained in two 1000-L outdoor raceway ponds with periodic addition of nutrients, an on-demand supply of carbon dioxide for pH control and carbon addition, and removal of 50% of the biomass during regular harvest intervals. During the six-week experiment, the harvesting frequency was increased from two to three to four times per week in each pond. Representative samples were collected (in triplicate) during harvest and evaluated for pH, temperature, and total and volatile suspended solids (VSS). Predominant algae genera were identified using light microscopy. Algal productivity was calculated based on the accumulation of VSS over the specific algal growth period (i.e. time between harvests) and is expressed as gVSS/m²-day. The results indicate that when the harvesting frequencies were increased from 2 to 3 to 4 times per week, average productivity increased from 8.3 to 11.7 to 16.1 gVSS/m₂-day in Pond A and from 9.0 to 13.3 to 16.3 gVSS/m²-day in Pond B. Thus, nearly twice as much biomass can be produced from microalgal ponds when harvesting frequencies are increased from 2 to 4 times per week.

  2. Mussoline³, W. and Wilkie, A.C. (2017). Sustainable Irrigation System for Rural Farming Operations.  18^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, November 13, 2017.

  Poster

  Abstract:

  A solar-powered irrigation system was designed and implemented at the Bioenergy and Sustainable Technology Laboratory community gardens.  The irrigation system was designed to harvest rainwater that would be dispersed through overhead sprinkler heads certified by Energy Star to promote water conservation.  The irrigation schedule was set for the evening hours to minimize evaporative losses at a rate of 200 gallons/day unless daily rainfall was sufficient.  The community gardens consisted of 1,800 square feet of seasonal vegetables planted in rows spaced 36 inches apart.  The inter-row spacing varied from one to two feet, depending on the crop.  The seasonal vegetables included potatoes, kale, squash, cucumbers, okra, peppers and eggplant.  Transplants were planted from February 15^th through March 15^th and the harvest schedule extended from April 19^th through September 4^th.  The crops were fertilized at a rate of 3 lbs N/1000 ft², based on recommendations following soil fertility analyses.  The objective of the project was to develop a sustainable model for maximizing agronomic productivity for a diverse selection of nutritional vegetables with minimal water and power inputs, specifically for rural and/or low socio-economic communities.  The agronomic harvest productivities for each crop were measured by pound of vegetable produced per plant and per acre.  Agronomic productivities (lbs/plant) were highest for cucumbers (18), eggplant (10), and squash (5) and were lower for kale (1.8), okra (1.5), potatoes (1.0) and peppers (0.8).  When expressed as lbs/acre, the crops descended in the same order and ranged from 260,839 lbs/acre for cucumbers to 12,232 lbs/acre for peppers.

  
  3. O’Connell¹, R. and Wilkie, A.C. (2017). Student Compost Cooperative – Making Campus More Sustainable.  18^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, November 13, 2017. Winner of Best Undergraduate Student Poster Award.

  Poster

  Abstract:

  Composting is a natural process in which microorganisms break down important available nutrients in various organic wastes including our food scraps, yard waste, animal manure, and garden waste. Once broken down, the recycled product can be used as a nutritious soil amendment in a garden without the use of commercial fertilizers. Composting helps to build organic matter in the soil which retains moisture, prevents diseases, and balances pH levels. Additionally, recycling our organic wastes reduces the amount that accumulates in large landfills which release greenhouse gases that contribute to climate change across the globe. Composting provides the opportunity for our communities to create a more sustainable future by decreasing our dependence on fossil fuels for waste management and fertilizer production. The Student Compost Cooperative (SCC) is a student-led organization established through the UF Soil and Water Sciences Department designed to provide students, faculty, and locals with the ability to compost their own organic wastes at our facility at the Bioenergy and Sustainable Technology Lab and learn the importance of composting. Through social media, the SCC coordinates and holds various educational workshops and hands-on events with the composters. Garden plots are available for those interested in starting to grow their own crops. The SCC aims to encourage and educate students on how they can contribute to making campus a more sustainable community.

• 2016 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. da Silva², E.B., Lessl, J.T., Wilkie, A.C. and Ma, L.Q. (2016). Phytoremediation of As-contaminated soils by As-hyperaccumulator Pteris vittata: Long-term Efficiency and Biomass Disposal.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016. Winner of Best Graduate Student Poster Award.

  Poster

  Abstract:

  • Arsenic (As) is toxic to plants, animals and humans. As-hyperaccumulator Pteris vittata (PV) can be used in As-contaminated soil remediation. However, disposal of the As-laden biomass might present a drawback of the phytoremediation process.
  • The ability of P. vittata in taking up As from three As-contaminated soils was assessed over 6 years using pots containing 162 kg soil, each supporting 9 plants. Besides, As extraction from PV biomass was assessed using water and 30% ethanol solution.
  • P. vittata reduced soil As concentrations by 45-47%, from 129, 26.6 and 29.8 mg kg^-1 to 69, 16 and 14 mg kg^-1.  However, efficiency decreased over time.
  • Arsenic in P. vittata biomass was ~60% water soluble and 85% ethanol soluble. Addition of MgCl₂ helped formation of magnesium arsenate precipitate [Mg₃(AsO₄)₂], reducing solution As concentration to < 2 mg L^-1.

  
  2. Hallas², J., Mackowiak, C. and Wilkie, A.C. (2016). Distributed Wastewater Treatment Plants – A Sustainable and Economical Phosphorus Source through Struvite Recovery.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016.

  Poster

  Abstract:

  Phosphorus (P) is a limited natural resource.  Municipal wastewater treatment plants (WWTPs) are accessible sources of renewable P through the formation of struvite (MgNH₄PO₄•6H₂O).  Total P loads to WWTPs can range from 2.1 to 4.1 g/capita/day with inflow concentrations of approximately 3.7 to 11 mg/L.  Struvite recovery from four distributed WWTPs in North Florida with treatment capacities from 371 to 2650 m³/day and incoming P loads from 2 to 14 kg/day was investigated.  Struvite formed by adjusting the pH of wastewater filtrate from an average of 7.0 to 8.5 using a base (NaOH). Air sparging was investigated as an efficient and economical alternative to using base.  Beaker experiments were used to compare struvite recovery using base additions with stirring versus air sparging.  Sparging was achieved with an air diffuser (bubble size 1-3 mm). The pH in the stirred beaker (no sparging) was adjusted by the addition of 5 N NaOH.  Struvite formation in the air-sparged treatment showed a 1-22% increase in yield from the wastewater filtrate in the stirred beaker treatment and an increase in purity from 12 to 45%.  Assuming an average struvite formation rate of 212 g/m³ of wastewater, the combined distributed WWTPs in the United States are capable of producing 1.2 million metric tons of P as P₂O₅ per year. This would reduce the global demand on phosphate mining by 3%.

  
  3. SWS2016-Poster-Mussoline.pdf³, W. and Wilkie, A.C. (2016). Bioenergy Recovery Scheme for Industrial Starch Crop and Associated Co-products.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016.

  Poster

  Abstract:

  Strategic and sustainable agricultural practices not only require innovative crop selection that will produce maximum yields with minimal resources, but also a zero-waste mentality.  In order to maximize both soil and land potential, every ounce of biomass within a crop should contribute to food, fuel or restoration of soil fertility.  The sweetpotato crop produces starchy roots and nutritious green tops that are both valuable end-products in regards to food or fuel.  From a bioenergy perspective, even damaged or diseased roots have significant value through methane recovery.  The objectives of this research were to evaluate the bioenergy potential of the products/co-products associated with an industrial sweetpotato crop (CX-1) and develop a bioenergy recovery scheme based on agronomic yields.  The ethanol yield was determined for the roots and methane yields were determined for three co-products, namely the aerial vines, culls, and stillage (byproduct of ethanol production).  Methanogenic batch assays conducted in triplicate at 35˚C for 40 days revealed methane yields (L of methane per kg of volatile solids added) of 305 ± 9 (vines), 364 ± 7 (culls), and 446 ± 6 (stillage).  Results showed that one acre of CX-1 sweetpotatoes has the potential to produce nearly 250 gallons of ethanol and nearly 50,000 MJ from methane gas.  While 20-40% of the energy would be necessary for the cultivation, transport and conversion of sweetpotato into ethanol (range dependent on conversion efficiencies), the remaining 60-80% represents excess energy that could be used for other purposes such as direct heat and/or electricity.

  
  Peralta¹, M.D. and Wilkie, A.C. (2016). Open-pond Cultivation of Microalgal Polycultures on Landfill Leachate.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016.

  Poster

  Abstract:

  Utilizing waste effluent for the production of renewable fuel sources not only reduces our dependence on fossil fuels but also provides an opportunity for environmental bioremediation.  Liquid that permeates through layers of municipal waste in landfills (landfill leachate) is a waste effluent that requires collection and costly treatment.  Landfill leachate (LL) has sufficient nutrients for microalgae cultivation, making it a viable growth medium for algae used in biofuel production.  Total ammonia nitrogen (TAN) is typically very high in LL, which hinders algal growth, prompting cultivation in diluted LL or determining other favorable conditions for growth.  The research objective was to grow indigenous microalgae outdoors in a 100-L raceway pond in non-diluted LL.  Mature leachate was collected from a closed landfill and characterized for pH, conductivity, alkalinity, solids concentrations and chemical oxygen demand.  The leachate was inoculated with a microalgal polyculture and monitored daily for pH, growth (optical density) and TAN.  Carbon dioxide was added continuously to the pond through a diffuser for pH control.  Microscopy was used to evaluate the biodiversity of the microalgal polyculture before and after the trial.  Results showed that algal biomass increased in 100% LL over the 11-day period.  CO₂ was an effective means of maintaining a neutral pH, which favored the presence of ionized ammonia (NH₄⁺) rather than unionized, free ammonia (NH₃) that can disrupt algal cellular metabolism. Certain algae strains were more tolerant than others.  The overall reduction of TAN from 825 to 4 ppm demonstrates the potential of microalgae for bioremediation of landfill leachate.

  
  Sanchez¹, C. and Wilkie, A.C. (2016). Bioenergy Production from Sheep and Goat Manure.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016.

  Poster

  Abstract:

  Sheep and goats require less land and feed than larger livestock, making them less expensive to maintain.  Their manure is in a pellet form that can easily be collected and utilized for bioenergy and biofertilizer.  Methanogenic bacteria from the animals’ ruminant digestive system are present in the manure.  Thus, sheep and goat manure are ideally suited feedstocks for anaerobic digestion to recover renewable energy (i.e. methane).  Sheep and goat manure are also rich in macronutrients including nitrogen and phosphorus, as well as micronutrients including iron, zinc and copper.  Following digestion, these nutrients remain in the effluent and can be used for soil amendment.  The objectives of this study were to characterize each manure type and determine their ultimate methane yields.  Fresh sheep and goat manure were collected locally and characterized for pH, conductivity, alkalinity, dry matter (DM), organic matter (OM), and chemical oxygen demand (COD).  The sheep manure had a pH slightly above neutral (8.10 ± 0.07) and thus would be beneficial for improving soil pH.  Methane index potential batch assays were conducted at 35°C for 40 days, in triplicate. Goat manure had higher DM and OM contents, resulting in a higher methane yield from goat (7.1 L CH₄/lb) versus sheep (5.1 L CH₄/lb) manure on a fresh weight basis.  However, both types of manure were determined to be viable for methane production.  Nutrient characterization in the post-digestion effluent is recommended to evaluate its potential biofertilizer value.

  
  Vasilevsky¹, M. and Wilkie, A.C. (2016). Student Compost Cooperative – Promoting Soil Health.  17^th Annual Soil and Water Sciences Research Forum, University of Florida, Gainesville, Florida, September 15, 2016.

  Poster

  Abstract:

  The Student Compost Cooperative (SCC) is a cross-disciplinary outreach program established by Dr. Ann Wilkie (Soil and Water Sciences Department, UF-IFAS) that fosters sustainability and nutrient upcycling through composting and sustainable gardening.  The SCC hosts demonstrations and hands-on activities, promotes collaboration among other on-campus organizations, and seeks to popularize sustainability and composting through social media.  The SCC also provides free garden plots for students that lack access to adequate space, while encouraging them to compost their food waste and use the finished product for their own organic gardens.  Composting is a biological, exothermic process in which organic wastes are decomposed into a nutritious soil amendment by macro- and microorganisms.  Macroorganisms are the physical decomposers that grind the material into smaller pieces, while the microorganisms convert organic matter into humus and break down the nutrients into a bioavailable form where they can be assimilated into plant matter.  Students learn to accelerate this process through appropriate nutrient ratios of carbon (leaves, twigs, cardboard) to nitrogen (fruit and vegetable waste, coffee grains, grass clippings).  Turning the pile improves oxygen transfer and provides more surface area contact for the microbes.  The advantages of composting are substantial, from the reduction of commercial fertilizer use, to improving soil health, and preventing nutrient leaching.  The SCC organizes workshops and interactive field days using social media to encourage participation.  All UF students, faculty and staff are invited to participate in the SCC to make this campus a more sustainable and interactive community of collective composters.

• 2015 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. Friedrichsen², C., Daroub, S. and Wilkie, A.C. (2015). Anthropogenic Factors that Influence Soil Management: Ethnopedology and Ethnopedozoology. 16^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 17, 2015.

  Poster

  Abstract:

  Ethnopedology is the study of a local population’s knowledge, belief and management of their soil. Ethnopedozoology is the study of human interactions with soil biota. Ethnopedology and Ethnopedozoology were developed to answer questions related to human-centered design including social, cultural, political and economic factors that influence soil management. These disciplines have also shown that local and scientific knowledge can be combined to find solutions for soil-related problems. Transdisciplinary research encounters many problems including the creation of new methods to answer research questions and how to communicate their findings. Currently, local knowledge is collected using qualitative methods and scientific knowledge through quantitative methods. Different methods have been used to integrate these two knowledge bases including GIS and participatory research but both methods have encountered challenges. The scope of ethnopedology research needs to be expanded to include the effect of local soil knowledge and beliefs on soil management. Ethnopedology also needs to include an examination of how green-revolution technologies affect the dynamic of local soil knowledge, beliefs and management. Ethnopedozoology is a new discipline, whose scope so far has only looked at macro fauna. An extension of the scope of ethnopedozoology to also include beneficial microorganisms would allow the scientific community to better understand how to communicate and facilitate adoptions of probiotics and composting. This would also create the opportunity for the scientific community to learn about a possible local management practice, which would promote soil biodiversity.

  
  Hafner¹, K.D. and Wilkie, A.C. (2015). Cellulosic Ethanol Stillage as a Cultivation Medium for Spirulina. 16^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 17, 2015. Winner of Best Undergraduate Student Poster Award.

  Poster

  Abstract:

  Algae are high-yielding plants and a potential alternative to conventional fossil fuels that can alleviate the greenhouse effect while simultaneously treating wastewater.  Cultivating algae requires high nitrogen inputs to sustain growth and produce feedstock biomass, providing a possible bioremediation option for high-ammonia wastewaters such as stillage from cellulosic ethanol production.  Cultivating algae on stillage can help to offset the energy consumed in the pretreatment and distillation operations of bioethanol production as it combines nutrient removal and algal production for potential use as a biofuel feedstock.  Thus, this creates a sustainable, closed-loop process.  The objective of this study was to determine the growth and remediation potential of Spirulina, a filamentous, blue-green algae with high biomass productivity, on sugarcane bagasse stillage.  Cultures were prepared with 10% inoculum in 125 mL Erlenmeyer flasks (50 mL active volume).  The treatment mediums consisted of 100% thin stillage (negative control), Spirulina Medium (positive control), and 2%, 5% and 10% concentrations of thin stillage with 1% (v/v) sodium bicarbonate.  The cultures were cultivated for 96 hours under 120 µmol photons/m²/s fluorescent lighting on a 24:0 (light:dark) photoperiod.  Cells were subjected to moderate mixing (120 rpm) provided by a mechanical shaker.  Algal growth was monitored spectrophotometrically using absorbance at 680 nm.  The data revealed that thin stillage in dilutions is promising for cultivating Spirulina.  Compared to algal growth in Spirulina Medium (1.96 g/L), the 2%, 5% and 10% thin stillage mediums exhibited max biomass yields of 1.47, 1.89, and 2.14 g/L, respectively.

  
  3. Hallas², J., Mackowiak, C. and Wilkie, A.C. (2015). Struvite Recovery from Small Wastewater Treatment Plants. 16^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 17, 2015.

  Poster

  Abstract:

  Municipal wastewater treatment plants (WWTPs) may be an attractive source of recoverable phosphorus (P) through precipitation of the mineral struvite (MgNH₄PO₄•6H₂O).  Struvite may be used as a slow-release fertilizer to supply a renewable source of P and nitrogen (N). The deliberate precipitation of struvite for P recovery has focused on large WWTPs, using digestate from the anaerobic digestion of biosolids. However, small WWTPs (< 12 MGD discharge) are typically operated through activated sludge processes and make up the majority of WWTPs, (97% in Florida and 98% nationally). Laboratory experiments with reagent-grade salts resulted in struvite product yields of approximately 71%, under ambient conditions (23 C), with equal molar (10 mmol) Mg²⁺, NH₄⁺, PO₄^3- concentrations that were within the range of aerobically digested sludge values. A chemical equilibria model, based upon a typical aerobically digested sludge filtrate composition was developed, using the computer program Visual MINTEQ version 3.1 to identify the ion activity product (IAP).  The model demonstrated favorable conditions for struvite formation at 3 of 4 operational WWTP sites in Leon County, FL, while the fourth site required a four-fold addition of Mg²⁺to promote struvite formation. The MINTEQ IAP model was used to track the molar concentration of struvite and other solid phases across a pH range of 4 to 14. Struvite precipitation was maximized at pH >10; however, the more alkaline range also resulted in competing solid phases, such as brushite (CaHPO₄·2H₂O), brucite (Mg(OH)₂), and newberyite (MgHPO₄). The MINTEQ IAP model indicated that 75-90% of maximum struvite precipitation should occur at a pH range from 8.5 to 9.0, resulting in less contaminant minerals. The lower pH target also translates to less modification of the WWTP digestates, which often range from approximately 7.5-8.5 pH units. Model validation is currently being performed by testing actual WWTP filtrate samples at pH ranges from 8.0 to 9.0.

  
  Mussoline³, W. and Wilkie, A.C. (2015). Evaluating the Bioethanol Potential of Industrial Sweetpotatoes in Florida.  16^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 17, 2015.

  Poster

  Abstract:

  Sweetpotato (Ipomoea batatas L.) is a starch-based crop that can be used for human consumption or biofuel production. The decision on whether to grow sweetpotatoes for food, fuel or manufactured products depends on the needs of the surrounding community. In Florida, an industrial sweetpotato variety (CX-1) is being considered as an alternative crop for citrus lost to greening. The CX-1 was selected for fuel ethanol production because of its large roots with high dry matter (DM) and elevated starch content. A field trial was conducted in Gainesville, Florida to determine the agronomic yields and corresponding starch yields of the CX-1. Rooted versus unrooted sweetpotato vine material was planted in raised beds, with three replications for each material type. Rooted plants were established in trays for 30 days prior to planting while unrooted cuttings were stripped from recently harvested vines and planted directly in the ground. Both plots were harvested 182 days after planting and weighed to determine agronomic yields. Roots were processed into flour immediately following harvest and also after six months of storage and then analyzed for total starch content. The agronomic root yields (DM basis) of the rooted and unrooted CX-1 crop were 3.1 and 1.8 tons/acre, respectively. The starch content of the rooted crop was also higher (71.2% DM) than the unrooted crop (68.5% DM), producing an overall starch yield of 2.2 tons/acre. No significant loss in starch was observed after storage suggesting that this crop could be utilized year-round as a feedstock for ethanol production.

• 2014 SWES Research Forum Student Posters

  [¹ Undergraduate student; ² Graduate student; ³ Postdoc]

  1. Hallas², J., Mackowiak, C. and Wilkie, A.C. (2014). Nutrient Recovery from Small Wastewater Treatment Plants. 15^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 18, 2014.

  Poster

  Abstract:

  Global demand for phosphorus (P), a finite resource, primarily derived from phosphate rock (P₂O₅), is estimated at 40 million tons per year, and is increasing by 1.5% annually.  An estimated 7 billion tons of P₂O₅ remain in reserves that can be economically mined and are expected to be exhausted within this century.  A sustainable source of phosphorus is essential to feed the world’s growing population.  Municipal wastewater treatment plants (WWTPs) may be an attractive source of recoverable P.  The mineral struvite (MgNH₄PO₄•6H₂O) is thermodynamically favorable to form in some wastewater streams.  Struvite may be used as a slow-release fertilizer to supply a renewable source of P.  It is estimated that 1 pound of struvite can be generated from ~12,000 gallons of municipal wastewater at a P recovery rate of 55%.  Thus, struvite may provide a sustainable P fertilizer while reducing P discharged by WWTPs.  The intentional precipitation of struvite for P recovery has focused on large WWTPs, using digestate from the anaerobic digestion of biosolids.  However, small WWTPs (< 12 MGD discharge) make up the majority of WWTPs, 97% in Florida and 98% nationally.  On the national scale, the total combined discharge of small WWTPs could produce ~2.2 million pounds of struvite per day.  Small WWTPs have the same permit limits for nutrients as do large WWTPs and they must achieve these nutrient reductions without the benefit of revenue from large customer bases or economies of scale.  Struvite production at small WWTPs may provide an economic benefit while assisting to meet future permit regulations and fertilizer P demand.

  
  Mussoline³, W. and Wilkie, A.C. (2014). An Energetic Perspective on Sweet Potato: Food Versus Fuel. 15^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September 18, 2014.

  Poster

  Abstract:

  Sweet potato (Ipomoea batatas L.) is a major starch-based crop that can be consumed as a nutritious dietary staple or converted into fermentable sugars for ethanol production. There are over 8000 varieties of sweet potato that have been bred for specific purposes. Varieties used for fuel generally have higher dry matter and starch contents, resulting in improved storage and increased ethanol yields, respectively. A high-dry matter sweet potato variety, CX-1, is being evaluated as a replacement crop for failing citrus groves in Florida since it can grow in hot climates, requires minimal irrigation and nutrients, and has a short growth cycle (150 days). The research objective is to determine whether sweet potatoes in Florida should be grown for human consumption or fuel production based on agronomic yield, potential energy production from both roots and culls, and nutrient recovery for animal forage. Varieties for comparison include Beauregard (food) and CX-1 (fuel). Ninety-six (96) plants of each variety were planted on June 6, 2014. Growth monitoring is conducted every six weeks and root/vine yields will be measured at harvest. Net energy values from ethanol production are twice that of edible energy for humans. Specific methane yields obtained from anaerobically digesting the culls were 333 and 255 LCH₄/kgCOD for Beauregard and CX-1, respectively. CX-1 culls have higher crude protein, nitrogen and phosphorus, while Beauregard are higher in fiber (CF, NDF, and ADF) and in vitro organic matter digestibility. Preliminary results favor CX-1 for ethanol production, but agronomic yields are essential for conclusive results.

  
  Nelson¹, B. and Wilkie, A.C. (2014). Nitrogen Starvation of Algae – a Stress for Lipids. 15^th Annual Soil and Water Science Research Forum, University of Florida, Gainesville, Florida, September18, 2014. Winner of Best Undergraduate Student Poster Award.

  Poster

  Abstract:

  Microalgae strains, such as Chlorella vulgaris, Chlorella minutissima, and Scenedesmus obliquus have been researched as potential feedstocks for biofuels because of their fast growth rate and ability to produce lipids.  In order for commercial-scale algae biofuel plants to become a reality, however, the conversion of algal lipids into biofuels needs to become more efficient.  One strategy to improve biofuel yields from algae is to induce lipid production using a two-stage nitrogen starvation method.  In this method, microalgae are grown in nutrient-replete conditions such as wastewater to achieve high biomass and are then transferred to nitrogen-depleted conditions to stimulate lipid production and increase overall lipid content.  The objective of this research is to test the viability of different aqueous conditions including tap water, distilled water, and deionized water, to determine which nitrogen-depleted medium results in the maximum lipid induction.  The results will indicate the optimal media characteristics including pH, conductivity, and trace organics for maximum lipid induction.  Chlorella cf. vulgaris was used for preliminary trials because of its availability and metabolic ability to produce lipids.  The reason for using water instead of a modified growth medium (nitrogen lacking) is cost, availability, and ease of access for commercial purposes.  Microscopic monitoring showed large amounts of lipids in both deionized and distilled water and very small amounts of lipids in tap water and the control.  The experiment is ongoing and lipid content measurements by nuclear magnetic resonance will be used to confirm and quantify results obtained by microscopic monitoring.

CUR Undergraduate Research Symposium

The UF Center for Undergraduate Research (CUR) sponsors the Undergraduate Research Symposium each fall and spring where students present posters on the research they've conducted.

Explore the CUR Undergraduate Research Symposium site to find information about upcoming symposia and see past posters that have been presented.

Dr. Ann Wilkie faculty mentor profile - Center for Undergraduate Research

Examples of BEST/Experiential Learning Lab Participation in UF Center for Undergraduate Research (CUR) Research Symposia

• 2024 Spring CUR Undergraduate Research Symposium

  Hardy, D. and Wilkie, A.C. (2024). Food Waste Composting – Efficiency of Starter Microbes. 2024 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 1, 2024.

  Food Waste Composting – Efficiency of Starter Microbes

  Duane Hardy¹ and Ann C. Wilkie²

  ¹ Plant Science Major

  ² Department of Soil, Water, and Ecosystem Sciences

  Class:  SWS 4905 – Individual Work in Soil, Water, and Ecosystem Sciences

  Globally, food waste management poses a significant challenge. Over one-third of food produced in the United States goes uneaten, making it a primary material in landfills and incinerators annually. This situation exacerbates environmental, societal, and economic issues, as the resources used for growing and transporting the wasted food are also lost. Composting, the natural breakdown of organic waste by aerobic microorganisms into compost, offers a viable solution for food waste management. This process turns organic waste into a substance usable as fertilizer or soil amendment. However, the efficiency of the process can vary based on a range of factors, including the initial microbial inoculum. In this study, a kinetic analysis was conducted on three different inocula to compare their efficiency to initiate active composting (thermophilic phase). The study employed four 5 L insulated metal containers with food waste (FW) as the primary feedstock. The study included four treatments (three microbial inocula plus one control): 1) FW + commercial activator, 2) FW + active compost, 3) FW + local garden soil, and 4) FW + control (no inoculum). As compared to the control, starting inocula provided a shorter timeframe to reach the active thermophilic phase.

   

  Kasprzak, K. and Wilkie, A.C. (2024). Sorghum bicolor Growth Shows Promise in Marginal North Florida Soils. 2024 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 1, 2024.

  Sorghum bicolor Growth Shows Promise in Marginal North Florida Soils

   Katya Kasprzak¹ and Ann C. Wilkie²

  ¹ Environmental Management in Agriculture and Natural Resources Major

  ² Department of Soil, Water, and Ecosystem Sciences

  Class:  SWS 4911 – Supervised Research in Soil, Water, and Ecosystem Sciences

  Increasing global population and energy demand necessitate a shift to renewable resources. Bioethanol, derived from crops like sweet sorghum (Sorghum bicolor), offers a sustainable alternative, but cultivation of energy crops can also deplete the soil of its nutrients and create marginal, non-fertile soils. During this study, the response of sweet sorghum to marginal sandy acidic soils in North Florida was evaluated, exploring the potential benefits of intercropping with the nitrogen-fixing crop red clover (Trifolium pratense) for increased nitrogen availability and reduced environmental impact. The impact of compost amendment on soil properties and sorghum growth was also evaluated. Sorghum and red clover were grown from seed in 3-gallon pots, in triplicate, in a non-climate-controlled greenhouse. Sorghum herbage accumulation and growth rate were evaluated, and soil was tested for Total-N, NH₄-N, NO₃-N, and pH to investigate the nitrogen uptake of sweet sorghum and output by red clover. Sweet sorghum showed the highest growth rate and herbage accumulation in the marginal soil control. Compost and red clover amended soils received greater NH₄-N and NO₃-N concentrations. Therefore, sorghum in these soils may have been overwhelmed with nitrogen or competition from surrounding crops.

   

  Wright, S. and Wilkie, A.C. (2024). Future Farming – Application of Sustainable Practices. 2024 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 1, 2024.

  Future Farming – Application of Sustainable Practices

  Savannah Wright¹ and Ann C. Wilkie²

  ¹ Soil Science Major

  ² Department of Soil, Water, and Ecosystem Sciences

  Class:  SWS 4911 – Supervised Research in Soil, Water, and Ecosystem Sciences

   This research study focused on converting a 35-foot by 65-foot area at the Bioenergy and Sustainable Technology Lab into a sustainable farming model. This involved employing eco-friendly “best management practices” to improve soil health and fertility. Methodology included land preparation, strategic planting, fertilization, watering, and harvesting, all supported by calculations for crop success. Throughout the study, organic fertilizers, cover cropping, and companion planting were used, along with precision agriculture tools to optimize efficiency and minimize plant disturbance. Emphasizing a smaller scale, the goal was to demonstrate the design and application of sustainable and regenerative practices for future adoption. The choice of cultivars and their strategic placement, such as intercropping Marigolds and Zinnias to attract pollinators, showcased an approach to creating a balanced and symbiotic ecosystem within the space. Additionally, the implementation of cover crops, including hairy vetch and clover, not only served as a barrier to weed growth but also contributed to nitrogen fixation, enriching the soil in a sustainable manner. These sustainable practices are scalable and will contribute to the advancement of a more resilient agricultural system.

   

• 2023 Spring CUR Undergraduate Research Symposium

  Claverie, C. and Wilkie, A.C. (2023). Biogas – Sustainable Energy for Rural Villages in Zambia. 2023 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2023.

  Poster

  Abstract:

  Access to reliable energy is a major challenge for developing countries where large rural populations rely on subsistence farming and cook their food over traditional wood-burning stoves or open fires.  Cooking with wood-burning stoves is also a significant health hazard, causing illness and death due to continuous smoke and particulate inhalation.  Biogas energy from the decomposition of organic matter in an oxygen-free environment (anaerobic digestion) offers a clean-burning alternative, much like propane or natural gas.  Common feedstocks for anaerobic digestion include livestock manure, food waste and crop residues.  The objective of this study was to assess the current and future potential for biogas energy in Zambia, where the electric-power grid serves only four percent of the 10.4 million mostly rural population.  The impact of biogas technology was analyzed in the context of energy use, deforestation, social and climate change effects.  The study indicates that biogas production in Zambia has the potential to provide clean energy in rural/remote areas, minimize deforestation, improve health and environmental conditions, and decrease greenhouse gas emissions.  To realize these benefits, however, policies are needed to create a market for bioenergy, transfer knowledge from experts to villagers, and promote the use of local materials for digester construction.

   

  Mondell, C. and Wilkie, A.C. (2023). The Sustainable Uses of Kenaf (Hibiscus cannabinus). 2023 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2023.

  Poster

  Abstract:

  Kenaf, an herbaceous annual, soft fiber crop may have the potential for commercial success in the state of Florida due to the high yields that can be obtained in the state’s warm climate. The crop can be cultivated for both fiber and seed production. In Central and North Florida, the climate makes kenaf cultivation more suitable for fiber production. The fibers can be used in various ways, such as for papermaking, as a raw material for composites, and as a sustainable oil absorbent to clean up spills. The core, as a waste product of fiber production, has the ability to be utilized as a growth medium for containerized plants and to be used as a filtration aid for pools. In South Florida, higher seed yields are obtained because the climate is more suitable for seed production in the region. Seeds can be utilized as a source of seed supply for other regions, and may even be used as a source of edible oil as a by-product. If the correct measures are taken, kenaf could become a valuable cash crop for the state and a sustainable alternative for use in various industries.

   

  Muchnok, H. and Wilkie, A.C. (2023). Selecting Optimal Berry Bushes for a Community Garden. 2023 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2023.

  Poster

  Abstract:

  Maintaining a fruit garden can have multiple benefits for human health and nutrition, as well as ecosystem benefits such as attracting pollinators and increasing biodiversity. However, prior to establishing a fruit garden, there are many factors to consider such as site selection, local climate and temperature, soil type and textures, irrigation methods, and exposure to sunlight. When selecting cultivars, one must consider which fruits will propagate best in the aforementioned conditions, as well as nutrient requirements, space, time of bloom, susceptibility and resistance to pests, and chill requirements. The community fruit garden located at the University of Florida’s BioEnergy and Sustainable Technology Laboratory contains fruits such as blueberry and blackberry bushes, and can be accessed by students and faculty who wish to connect with local nature. Optimal berry bushes for this community garden were selected based on available space and time to fruiting.

• 2022 Spring CUR Undergraduate Research Symposium

  Thompson, T. and Wilkie, A.C. (2022). Propagating Spearmint Plants ( spicata) from Stem Cuttings. 2022 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 7, 2022.

  Poster

  Abstract:

  Mint plants can have a variety of different uses both commercially and residentially. In a commercial setting, mint can be used to produce dental hygiene products such as toothpaste and mouthwash. However, in a residential setting, people use it in foods, teas, baths, and even bug repellents. In light of its various uses, this study attempts to optimize the process of propagating mint plants from stem cuttings to quickly and effectively produce mint leaves. This study compared various treatments of mint cuttings, including the use of a rooting hormone, indole-3-butyric acid. The study was conducted in a greenhouse over the course of a few months. The propagated mint plants were measured by number of roots, length of roots, size of the plants, number of leaves, and the SPAD meter readings on the leaves of the plants. Results of the propagation study will be presented. This study works to improve current practices for mint propagation for commercial and residential use.

  Van, B. and Wilkie, A.C. (2022). The Student Compost Cooperative: Analytics of Educational Outreach. 2022 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 7, 2022.

  Poster

  Abstract:

  The Student Compost Cooperative (SCC), a facility located at the Bioenergy and Sustainable Technology Laboratory, provides members with sustainable opportunities to complement their lifestyles. During the Spring 2021 semester, we studied how many individuals the SCC onboarded and educated across different academic disciplines and backgrounds about food waste composting and other sustainable practices. To accomplish this, attendance data from weekly orientation/education sessions were collected via an online form accessed by QR code and analyzed. The analysis concluded that students from the College of Liberal Arts and Sciences (CLAS) and the College of Agricultural and Life Sciences (CALS) represented the highest proportion of orientees. More so, word-of-mouth was identified as the primary way orientees became aware of the SCC. Approximately a year has passed since the establishment of this data collection strategy and, with the conclusion of this semester, a year will have passed since the initial analysis of the data. As of March 17th, 2022, CLAS and CALS remained as the largest affiliation of students, but word-of-mouth no longer held the majority as an outreach method. The SCC continues to be successful in promoting and encouraging sustainable practices across different colleges at the University of Florida and in the local community. Our analysis shows that the SCC serves as a university and community accessible resource for composting and sustainability education.

  Valletti, L. and Wilkie, A.C. (2022). Food Waste Audit Conducted at the Student Compost Cooperative. 2022 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 7, 2022.

  Poster

  Abstract:

  There is an exorbitant amount of food waste generated worldwide, with over 1.3 billion tons of food waste discarded annually. The Student Compost Cooperative (SCC) at the Bioenergy and Sustainable Technology Laboratory provides a space for students and community members to compost their food waste in Gainesville, Florida. The objective of this study was to quantify the amount of food waste that was brought to the SCC, and thereby diverted from the landfill. Over the course of six months, October 2021 through March 2022, the collected food waste was audited and analyzed. An on-site scale was provided for participants to weigh the mass of food waste contributed to the compost bins. Data was analyzed on an individual participant and on an overall basis. The individuals who deposited their food waste during this time also completed a participant survey to determine what factors influence their likelihood to compost. Some key findings identified in the analysis include the total weight of food waste composted per person, the specific composition of the food waste, and one-time versus repeater participant behavior.

• 2021 Spring CUR Undergraduate Research Symposium

  2021 Spring CUR Undergraduate Research Symposium

  March 25, 2021

  BioEnergy and Sustainable Technology Laboratory - Presenters:

  1. Lars Bjorndal - Optimization of Algal Dehydration Kinetics

  Bjorndal, L. and Wilkie, A.C. (2021). Optimization of Algal Dehydration Kinetics.  2021 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 25, 2021. https://cur.aa.ufl.edu/public_presenter/lars-bjorndal/   

  Poster

  Poster

  Abstract:

  Algae cultivation has multiple environmentally-oriented applications including biofuel production, wastewater treatment, and carbon capture.  However, costs associated with extraction and dehydration remain a challenge for viable commercialization. Research has focused mainly on microalgae, but filamentous algae such as Oedogonium have gained attention due to their larger size and resulting ease of harvesting. Oedogonium has also been seen to occasionally self-entangle and form spherical aggregates which further facilitates harvesting. These aggregates generally dry slower than unaggregated Oedogonium.  This study investigated drying optimization by using a blender to reduce the aggregates to a slurry and fracturing the Oedogonium filaments.  Blended and unblended triplicates of aggregates with spherical diameters of 4-6mm, 9-11mm, and 13-15mm were dried in an oven at 50℃, and the blended samples dried 29%, 6%, and 41% faster, respectively, than the unblended aggregates.  Further, while the total drying times of the 4-6mm and 9-11mm unblended aggregates were relatively similar at 255min and 240min, respectively, the total drying time of the 13-15mm aggregates was 330min, which is significantly longer.  These findings confirm that processing aggregated Oedogonium can significantly reduce its drying time and that, if no processing is done, total drying time will greatly increase when aggregates exceed a certain size.

  2. Ceri Borde - Sustainability Analysis of Agricultural Development in Trinidad and Tobago

  Borde, C. and Wilkie, A.C. (2021). A Sustainability Analysis of Trinidad and Tobago.  2021 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 25, 2021. https://cur.aa.ufl.edu/public_presenter/ceri-borde/   

  Poster

  Abstract:

  Small island sustainability is a very precarious topic involving the careful data collection of local resources and ensuring enough is available for use within the present and future generations to come. Trinidad and Tobago is a collection of islands in the Caribbean that is known for its once large natural gas reservoir that has continued to be the economic engine and mainstay of financial prosperity for the country, compared to relying heavily on tourism as a revenue source. However, as the reserve of fuel slowly depletes with an increasing population size and consumption rate, there has been discussion and policies developed in the process that encourage greater attention to and welfare of the limited resources, specifically fuel, freshwater and arable land. The research conducted in this study will identify the inventoried resources currently available in Trinidad and Tobago. In addition, the study will outline the difficulties and constraints that prevent Trinidad and Tobago executing a quick solution to an otherwise time-sensitive issue, with small islands continually experiencing the effects of global climate change and human development influencing the availability of local resources.

  3. Katherine Messer - Analysis of Earthworm Depuration Conditions and Kinetics

  Messer, K. and Wilkie, A.C. (2021). Analysis of Earthworm Depuration Conditions and Kinetics.  2021 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 25, 2021. https://cur.aa.ufl.edu/public_presenter/katherine-messer/   

  Poster

  Abstract:

  Earthworms are used as biomarkers to determine the bioavailability of contaminants. As such, their uptake of contaminants has been studied extensively. Protocols have been established to ensure that laboratory-obtained data are valid and comparable. However, the method of removing the organism’s gut content (depuration) before assessing the contaminant in the tissue is not standardized. The aim of this research project is to investigate some parameters for earthworm depuration: light conditions and coprophagy prevention. Eisenia fetida were depurated for 48 hours in two separate studies according to guidelines ASTM-E1676 and OECD Test No. 317. In one study, the subjects and material egested were assessed under conditions of continuous light and continuous darkness. In another study, three filter paper change frequencies were employed during depuration to prevent coprophagy. The earthworms depurated in continuous darkness egested 94% more material per mg of earthworm than the earthworms in continuous light. The depuration methods that included a filter paper change every 12 and 24 hours resulted in 62% and 10% more egested material per mg of earthworm than the control with no filter paper change, respectively. The results indicate that depuration would be faster and more total under continuous darkness and employing a coprophagy prevention method. These findings could lead to more efficient depuration methods.

  4. Laura Valletti - Public perception to composting and perceived barriers to compost participation

  Valletti, L. and Wilkie, A.C. (2021). Public Perception of Composting and Perceived Barriers to Compost Participation.  2021 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 25, 2021.  https://cur.aa.ufl.edu/public_presenter/laura-valletti/   

  Poster

  Abstract:

  This study aims to determine interest in composting and environmental issues, as well as specific motivations to engage in environmentally friendly practices, with a focus on composting.  A 14-question survey was used to gauge the interest and participation in said practices by 315 participants who were a combination of University of Florida students and nonstudent Gainesville, Florida residents.  The results from this dataset indicated an interest in environmental issues and a desire to participate in composting among participants.  The main perceived barriers to participation were a lack of time, space and education.  Based on the results, it can be concluded that there is a desire and perceived need to compost and perform other ‘environmentally friendly’ actions among participants.  However, there is a disconnect when it comes to putting those interests and desires into action.  There has been a major culture shift concerning ideas about the importance of environmental issues, but much work remains to be done in putting these newly popular ideals into actions.

  5. Brian Van - The Student Compost Cooperative - Cultivating Compost Collaboration

  Van, B. and Wilkie, A.C. (2021). The Student Compost Cooperative – Cultivating Compost Collaboration.  2021 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 25, 2021.  https://cur.aa.ufl.edu/public_presenter/brian-van/   

  Poster

  Abstract:

  Composting is an organic and microbial process that transforms food waste into a nutrient-rich soil amendment.  Unfortunately, a majority of food waste is directed to landfills or wastewater treatment plants, whereby landfills emit greenhouse gases into the atmosphere, and wastewater treatment plants lose valuable energy to manage the food waste.  By composting, society can grow beneficial microorganisms, boost soil aeration, improve water retention, provide valuable nutrients for plants, and curb environmental damage.  Established by the Soil and Water Sciences Department, UF-IFAS, the Student Compost Cooperative (SCC) acts as a cross-disciplinary education and outreach program to develop sustainable practices amongst the campus and community population.  Through lectures and orientations, participants are able to engage with and learn about the composting process as it relates to their actions and the actions of fellow participants.  Furthermore, garden plots are also available for participants to use the compost and grow fresh produce.  As a result, the SCC is cultivating a collaborative effort across the academic spectrum to compost and engage in sustainable practices.  Students and staff are welcome to join the SCC in the effort to make the Gainesville area more sustainable by working together and composting their food waste.

• 2020 Spring CUR Undergraduate Research Symposium

  2020 Spring CUR Undergraduate Research Symposium

  April 2, 2020

  BioEnergy and Sustainable Technology Laboratory - Presenters:

  1. Daisy Andrews - Student Compost Cooperative – “Plate-to-Plate” Sustainability

  Andrews, D. and Wilkie, A.C. (2020). Student Compost Cooperative – “Plate-to-Plate” Sustainability.  2020 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 2, 2020. https://cur.aa.ufl.edu/2020/05/20/andrews-daisy/  

  Poster

  Abstract:

  Composting is a natural process by which organic wastes decompose into a nutrient-rich soil amendment.  Compost enriches the soil with organic material and improves water retention.  By reducing the disposal of organic waste into landfills, composting decreases greenhouse gas emissions and reduces demand for commercial fertilizers.  The Student Compost Cooperative (SCC) is a cross-disciplinary education and outreach program established by the Soil and Water Sciences Department, UF-IFAS, that fosters sustainability and nutrient upcycling through composting, gardening and rainwater harvesting.  The SCC provides free garden plots at the BioEnergy and Sustainable Technology (BEST) Laboratory, allowing students to utilize the compost on-site and establish a circular “plate-to-plate” sustainability practice whereby food waste is repurposed to grow fresh nutritious food.  While the SCC was originally established to promote composting of food scraps, it has grown to foster a diverse community working to eliminate waste, promote organic gardening, and to learn about sustainable living and a circular economy.  The SCC hosts tours and events, promotes collaboration among other organizations, and strives to popularize sustainability through social media.  All students and staff are invited to participate in the SCC to make the UF campus a more sustainable community by supporting plate-to-plate sustainability.

  2. Lars Bjorndal - Dehydration Kinetics of the Filamentous Alga Oedogonium

  Bjorndal, L. and Wilkie, A.C. (2020). Dehydration Kinetics of the Filamentous Alga Oedogonium.  2020 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 2, 2020. https://cur.aa.ufl.edu/2020/04/14/bjorndal-lars/

  Poster

  Abstract:

  Algae cultivation has multiple potential applications including biofuel production, wastewater treatment, and carbon capture.  However, dewatering and dehydration remain a challenge for commercialization.  Research has focused mainly on microalgae, but filamentous algae have recently gained attention due to their larger size and thus relative ease of harvesting.  The drying mechanics of filamentous algae has yet to be fully understood and optimized.  This study investigated the drying behavior of the filamentous algae Oedogonium at 50℃, 60℃ and 70℃.  The moisture content of triplicate samples of microalgae and Oedogonium (intact filaments, fractured filaments, and aggregated forms) was measured during drying.  Intact Oedogonium filaments were fractured using a food blender.  Results indicated a higher drying efficiency of Oedogonium in comparison to microalgae.  At 50℃, fractured Oedogonium filaments maintained an average drying rate of -0.56±0.07% per minute for 165 minutes compared to -0.51±0.07% per minute for the microalgae and the intact and aggregated Oedogonium.  However, this drying effect decreased significantly at 60℃, and at 70℃ all algae dried at similar rates.  Thus, fracturing the Oedogonium filaments resulted in faster dehydration at 50℃.  Reducing the duration and energy cost of drying helps to facilitate commercialization of algae cultivation.

  3. Katherine Messer - Composting - Fostering a Culture of Sustainability

  Messer, K. and Wilkie, A.C. (2020). Composting – Fostering A Culture of Sustainability. 2020 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 2, 2020. https://cur.aa.ufl.edu/2020/04/14/messer-katherine/

  Poster

  Abstract:

  According to the most recent Inventory of U.S. Greenhouse Gas Emissions and Sinks, landfills are the third-largest contributors of methane emissions, largely due to decomposing organic matter.  These organic wastes and carbon-based materials can be recycled and turned into a nutrient-rich soil amendment by composting.  By diverting organic waste from landfills, composting reduces greenhouse gas emissions and dependence on commercial fertilizers.  A 2014 National Waste & Recycling Association survey found that 72% of Americans do not compost their food waste and 62% would not support an increase in the cost of their waste and recycling service.  This project’s purpose was to identify trends, if any, in people’s perception of climate change and their involvement in composting and gardening.  This relationship was quantified using a Qualtrics survey and delivered to UF and Santa Fe Students using social media platforms, Facebook and GroupMe.  The survey questions were categorized into three groups: demographics, knowledge of climate change, and perception of composting.  It was anticipated that participants exposed to a community centered on sustainable living were more likely to engage in practices like composting.  Further analysis of this data can be used to strategically expand community gardens and foster a culture of waste reduction.

• 2019 Spring CUR Undergraduate Research Symposium

  Bjorndal, L. and Wilkie, A.C. (2019). Rainwater Collection Saves Water and Energy.  2019 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2019.

  Poster

  Abstract:

  With a growing world population, it is becoming more challenging to meet an increasing water demand. Florida gets most of its fresh water from groundwater (6.4 billion gallons/day) but, with a predicted 18% increase in water usage from 2015 to 2035, this will cease to be a sufficient source. Excessive groundwater use has negative environmental impacts such as saltwater intrusion, lowered lake levels and loss of wetlands. Alternative water sources will be essential to meet future demand. This project aims to quantify and understand the potential water and energy savings of using localized rainwater collection to supplement domestic and commercial water use. Local rainwater collection and storage uses water that is already available and reduces the energy expended on extraction and transport. The annual rainfall in Florida is between 40 and 60 inches per year. In Alachua County, depending on the time of year, a 1000 square feet area has the potential to collect 40-160 gallons/day. Although not necessarily suitable for drinking, rainwater could be utilized for flushing toilets and outside uses which are responsible for over 60% of an average American household’s water usage. Rainwater utilization, therefore, has a potential to reduce water demand and its related energy consumption.

  
  Higgins, B. and Wilkie, A.C. (2019). Fluorescent Microscopy of Fecal Samples from Five Orders of Mammals to Investigate Methanogen Presence.  2019 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2019.

  Poster

  Abstract:

  Animal wastes have been studied as potential fuel sources via bio-digestion.  Feces have also been used to inoculate biodigesters. Biodigesters are a waste solution which converts organic matter into a fuel source such as methane. They utilize microbes to breakdown organic matter into substrates, which are then converted into methane as fuel. The final step’s productivity depends on the methanogen content of the biodigester. This study serves to examine the feces of captive animals for use as a digester inoculum. The aim was to assess the potential of different feces for methanogen contribution through literature and sample analysis via fluorescent microscopy looking for F420 autofluorescence. Coenzyme F420 is a fluorescent coenzyme involved in redox reactions in methanogens and has been used in their identification and observation.  The samples were from herbivores in the orders Rodentia, Lagomorpha (rabbits), Perissodactyla (odd toed ungulates), Artiodactyla (even toed ungulates) and Diprotodontia (some marsupials). The project thus far has been impeded by two dilemmas: the scarcity of methanogens and obscuring from foliage. Due to these contrasting problems, the aim has been minimizing foliage obscurity while retaining enough methanogen presence. It was observed with a series of dilutions that a 1:10 dilution reduced foliage impact.

  
  McGann, J. and Wilkie, A.C. (2019). Student Compost Cooperative – Diverting Food Waste from Landfills.  2019 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2019.

  Poster

  Abstract:

  Composting is a natural process by which organic wastes decompose into a nutrient-rich soil amendment. Nutrients in organic matter like food scraps and yard trimmings can be recycled for use in agriculture, horticulture, and landscaping. Compost enriches soil with organic material and improves water retention, while also reducing disposal of organic waste into landfills. This decreases greenhouse gas emissions and reduces demand for commercial fertilizers. The Student Compost Cooperative (SCC) is a cross-disciplinary outreach program established by the Soil and Water Sciences Department, UF-IFAS, that fosters sustainability and nutrient upcycling through composting and gardening. The SCC has six composting bins, three rainwater harvesters, three vermiculture composters, a greenhouse, and two caterpillar enclosures to promote pollinators. The SCC provides free garden plots at the BioEnergy and Sustainable Technology (BEST) Laboratory, encouraging students to compost their food waste and use the finished product in their own organic gardens. Students can also pot plants for the greenhouse or the herb table near the plots. The SCC hosts tours and events, promotes collaboration among other organizations, and strives to popularize sustainability through social media. All students and staff are invited to participate in the SCC to make the UF campus a more sustainable community.

  
  O’Connell, R. and Wilkie, A.C. (2019). Growth of Filamentous Algae Compared to Microalgae.  2019 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2019.

  Poster

  Abstract:

  As the planet faces depletion of its natural resources, alternative and sustainable energy sources are becoming increasingly sought after. Research on the growth of algae has revealed their potential for carbon capture to reduce greenhouse gas emissions and for conversion into a fuel source for bioenergy applications. Filamentous algae have attracted recent attention as an optimal species for cultivation due to their ease of harvest and dominance over other species. To determine the most suitable species for future biomass applications, a 1000-L open raceway pond was inoculated with the freshwater filamentous alga, Oedogonium, with the addition of CO₂. An additional two 1000-L raceway ponds with established cultures of microalgae already receiving CO₂ were used as a comparison to the growth of Oedogonium. The pond cultures were harvested weekly to determine culture density/growth (mg VSS/L) and harvest productivity (g VSS/m²-day). After 3 weeks, Oedogonium harvest productivity exceeded both microalgal ponds at 13.7 (± 0.3) g VSS/m²-day compared to 9.3 (± 0.6) and 9.5 (± 0.5) g VSS/m²-day for the microalgae. Thus, Oedogonium could serve as a suitable species for biomass production due to its higher productivity rates when compared with microalgal growth.

  
  Upchurch, J. and Wilkie, A.C. (2019). University of Florida Student Vermicomposting Awareness and Implementation.  2019 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 4, 2019.

  Poster

  Abstract:

  Landfills are the third-largest contributor to U.S. methane emissions, due to decomposing organic matter. Vermicomposting, a form of composting that uses worms, can help mitigate greenhouse emissions while producing valuable organic fertilizer. This project’s purpose was to quantify the relationship, if present, between awareness of vermicomposting and action taken to ensure food waste is vermicomposted. Quantification of this relationship was evaluated by a survey employing skip logic. Once a participant demonstrated previous knowledge regarding vermicomposting, further higher-level questions were administered to determine level of awareness and action taken to ensure vermicomposting of food waste. Questions delivered in the survey were broken up into three categories: personal background, previous knowledge, and perception of vermicomposting. These areas provided insight in the development of methodology to implement vermicomposting at a wider scale. The sample group of this survey consisted of UF students reached through the UF Class of 2022 Facebook group. The survey utilized Qualtrics, a complimentary surveying program for UF students, and was conducted through Facebook. Upon completion of the survey and analysis of data, a sample of college student’s perception of vermicomposting was determined. Further analysis helped propose methodology which would prove most effective towards wider-scale implementation of vermicomposting.

• 2018 Spring CUR Undergraduate Research Symposium

  Bjorndal, L. and Wilkie, A.C. (2018). Solar Cooking for Disaster Relief.  19^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 22, 2018.

  Poster

  Abstract:

  Solar energy is arguably the most abundant resource in the world and enabling people to utilize this resource can be a powerful tool in elevating the standards of living in developing countries and disaster struck areas.  Solar cookers are relatively simple to construct and can be cheaply produced and distributed.  They have great potential in disaster and humanitarian relief situations, like what occurred in Puerto Rico and other Caribbean islands after the recent hurricane Irma.  A solar cooker is easy to use and relies only on sunlight to work.  In areas with limited electricity, it could provide a sanitary and effective way of preparing food, thus helping prevent diseases and malnutrition.  Further, the use of a solar cooker could potentially reduce air pollution and respiratory illnesses from traditional cooking fires that burn wood or charcoal.  A solar cooker uses sunlight to directly generate heat and therefore has a very high energy efficiency.  In a preliminary test, 1.5 liters of water were heated to a temperature of over 60 deg.C within an hour.  While this result can be further improved with optimization of the cooker, this temperature would still be sufficient to kill harmful bacteria and prepare a safe meal.

   

  Higgins, B. and Wilkie, A.C. (2018). Effect of Harvesting Frequency on Microalgal Productivity.  19^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 22, 2018.

  Poster

  Abstract:

  Many factors contribute to algal productivity including availability of light and nutrients, pH, temperature, algae species, and retention time.  The objective of this study was to evaluate the effect of harvesting frequency on microalgal productivity.  Microalgal polycultures were maintained in two 1000-L outdoor raceway ponds with periodic addition of nutrients, an on-demand supply of carbon dioxide for pH control and carbon addition, and removal of 50% of the biomass during regular harvest intervals.  Representative samples were collected (in triplicate) during harvest and evaluated for pH, temperature, and total and volatile suspended solids (VSS).  Predominant algae genera were identified using light microscopy.  Algal productivity was calculated based on the accumulation of VSS over the specific algal growth period (i.e. time between harvests) and is expressed as gVSS/m²-day.  The results indicate that when the harvesting frequencies were increased from 2 to 3 to 4 times per week, average productivity increased from 8.3 to 11.7 to 16.1 gVSS/m²-day in Pond A and from 9.0 to 13.3 to 16.3 gVSS/m²-day in Pond B.  Thus, nearly twice as much biomass can be produced from microalgal ponds when harvesting frequencies are increased from 2 to 4 times per week.

   

  O’Connell, R. and Wilkie, A.C. (2018). Culture Density and Harvest Productivity of the Alga Oedogonium.  19^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 22, 2018.

  Poster

  Abstract:

  As the planet is faced with depletion of its natural resources, alternative and sustainable energy sources are becoming increasingly sought after.  Research on the growth of algae has revealed their potential as a fuel source for bioenergy applications, their use as an animal feed, and their ability to remove nutrients from wastewater treatment plants.  Two 1000 L raceway ponds were inoculated with the filamentous algae, Oedogonium sp., to determine their growth patterns in an outdoor environment with temperature and pH fluctuations.  Discovering the optimal conditions for the growth of Oedogonium sp. could lead to their ease of cultivation for sustainable purposes in the future.  An additional two 1000 L raceway ponds were inoculated with diverse microalgal species to compare their growth and productivity to the filamentous Oedogonium sp.  The pond cultures were harvested and sampled to determine culture density (mgVSS/L) and biomass productivity (gVSS/m²-day) over weekly periods.  During colder winter months, Oedogonium sp. were found to change their morphotype, growth slowed, and the cultures transitioned to a maintenance mode.  With warmer temperatures, harvest productivity increased slightly as the cultures entered a growth phase.  The algae cells became greener, and their morphology reverted to long, thin filaments.

   

  Richardson, S. and Wilkie, A.C. (2018). Student Compost Cooperative – Reducing UF’s Carbon Footprint.  19^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 22, 2018.

  Poster

  Abstract:

  Composting is a natural decomposition process in which organic wastes decompose into a nutritious soil amendment.  Nutrients in organic wastes such as food scraps, spoiled fruits and vegetables, garden wastes, and yard trimmings can be recovered and recycled for use in agriculture, horticulture and urban gardening.  Not only does compost enrich the soils with organic matter and improve water retention, it also significantly reduces landfill disposal of organic waste and demand for commercial fertilizers, thereby reducing society’s reliance on fossil fuels and paving the path toward a sustainable future.  The Student Compost Cooperative (SCC) is a cross-disciplinary outreach program established by the Soil and Water Sciences Department, UF-IFAS, that fosters sustainability and nutrient upcycling through composting and sustainable gardening.  The SCC hosts educational demonstrations and hands-on activities, promotes collaboration among other on-campus organizations, and strives to popularize sustainability and composting through social media.  The SCC also provides free garden plots for students at the BioEnergy and Sustainable Technology (BEST) Laboratory, and encourages them to compost their food waste and use the finished product for their own organic gardens.  All students and staff are invited to participate in the SCC to make the UF campus a more sustainable community.

• 2017 Spring CUR Undergraduate Research Symposium

  Goff, J. and Wilkie, A.C (2017). Carbon Capture and Utilization – The Algal Way. 18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  Coal power plants introduce an abundance of carbon dioxide (CO₂) into the atmosphere. Algae can be grown using this CO₂ to reduce carbon emissions, and the harvested biomass can be anaerobically digested to produce methane gas (CH₄).  To evaluate the feasibility of growing algae on flue gas, locally sourced algae were cultivated in eight open raceway ponds operated under similar conditions of pH control, fertilization rate and harvest frequency.  Pond cultures were harvested and characterized for total solids (TS), volatile solids (VS) and chemical oxygen demand (COD).  Light microscopy was used to identify the different algal genera in each pond in order to understand how the different morphotypes might affect methane production.  Five ponds consisted predominantly of microalgae, while the other three were predominantly filamentous cultures.  Methane index potential (MIP) batch assays were conducted in triplicate at 35˚C for 28 days on the harvested algae.  On average, the filamentous algae had significantly higher methane yields (464 LCH₄/kgVS) than the microalgae (163 LCH₄/kgVS) due to their less rigid cell-wall structure allowing the biomass to be more readily converted into CH₄.  The research demonstrated that algae can be utilized to lower carbon emissions while providing an alternative and renewable energy source.

  
  Higgins, B. and Wilkie, A.C. (2017). Algal Population Dynamics in an Outdoor Algal Raceway. 18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  With mounting concerns of climate change, society’s reliance on fossil fuels must shift toward renewable and sustainable energy-producing systems.  Innovative research on the cultivation, growth, harvesting and bioenergy potential of algae may reveal the solution to energy demands of the future.  To investigate the scale-up potential of algal systems, outdoor raceway ponds were established and maintained in open conditions to promote interaction with the environment.  Open systems, however, are susceptible to seasonal changes such as temperature and as well as changing atmospheric conditions and airborne exposures.  A 1000-L open raceway pond was initially inoculated with a local algal mixed culture and population transitions were observed over a one-year experimental period.  The pH and temperature were continuously monitored, and pH was controlled by the addition of carbon dioxide on an as-needed basis.  The algal cultures were tracked by brightfield microscopy and complex patterns of succession were demonstrated.  Within six weeks of inoculation, long filaments fragmented into shorter filaments, followed by complete disappearance of the filamentous algae and displacement by microalgae cultures.  The current prevalence of microalgae genera, namely Scenedesmus and Pediastrum, have been relatively stable for the last six months indicating their persistence despite changing environmental conditions.

  
  O’Connell, R. and Wilkie, A.C. (2017). Student Compost Cooperative – Fostering a Sustainable Campus.  18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  Composting is a natural decomposition process in which organic wastes decompose into a nutritious soil amendment.  Nutrients in organic wastes such as food scraps, spoiled fruits and vegetables, garden wastes, and yard trimmings can be recovered and recycled for use in agriculture, horticulture and urban gardening.  Not only does compost enrich the soils with organic matter and improve water retention, it also significantly reduces landfill disposal of organic waste and demand for commercial fertilizers, thereby reducing society’s reliance on fossil fuels and paving the path toward a sustainable future.  The Student Compost Cooperative (SCC) is a cross-disciplinary outreach program established by the Soil and Water Sciences Department, UF-IFAS, that fosters sustainability and nutrient upcycling through composting and sustainable gardening.  The SCC hosts educational demonstrations and hands-on activities, promotes collaboration among other on-campus organizations, and strives to popularize sustainability and composting through social media.  The SCC also provides free garden plots for students at the BioEnergy and Sustainable Technology (BEST) Laboratory, and encourages them to compost their food waste and use the finished product for their own organic gardens.  All students and staff are invited to participate in the SCC to make the UF campus a more sustainable community.

  
  Palino, G. and Wilkie, A.C. (2017). Post-Harvest Algal Pretreatment using Biological Control.  18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  The mass cultivation of algae is a developing field with many potential applications in both industry and agriculture.  Algal biomass can be anaerobically digested to produce methane.  An effective way to generate a significant amount of biomass is through outdoor open raceway ponds, but these cultures are susceptible to contamination from insects.  Efficient pretreatment methods using biological controls may be necessary to obtain the maximum methane generation from pure algal feedstocks.  Algae contaminated with insect larvae were harvested from a 1000‑L open raceway pond located at the Stanton Energy Center in Orlando, Florida.  The insects were identified as midge fly larvae by microscopy.  One of the common predators of these larvae is the Giant Danios minnow, which have a primarily carnivorous diet.  Two minnows were placed in separate 5.5 gallon fish tanks and fed approximately 139 worms per day in the form of a wet pellet mixture of algae and larvae.  The concentration of larvae in the harvested algae was 18 larvae/g of wet biomass.  The biological pretreatment resulted in 99% removal of the insect contamination over a 24-hour treatment period.  Thus, Giant Danios minnows could serve as a feasible pretreatment method to remove insect larvae from harvested algae.

  
  Peralta, M.D. and Wilkie, A.C. (2017). Outdoor Cultivation of Microalgal Polycultures on Landfill Leachate.  18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  Landfill leachate (LL) has sufficient nutrients for microalgae cultivation, making it a viable growth medium for algal biomass production.  Total ammonia nitrogen (TAN) is typically very high in LL, which hinders algal growth, prompting cultivation in diluted LL or determining other favorable conditions for growth.  The research objective was to grow indigenous microalgae on raw LL in a 100-L outdoor raceway pond.  Mature leachate was collected from a closed landfill and characterized for pH, conductivity, alkalinity, solids concentrations and chemical oxygen demand.  The leachate was inoculated with a microalgal polyculture and monitored daily for pH, growth (optical density) and TAN.  Carbon dioxide was automatically added as needed for pH control, through a diffuser.  Microscopy was used to evaluate the biodiversity of the microalgal polyculture before and after the experimental trial.  Results showed that algal biomass increased in 100% LL over the 11-day period.  CO₂ was an effective means of maintaining a neutral pH, which favored the presence of ionized ammonia (NH₄⁺) rather than unionized, free ammonia (NH₃) that can disrupt algal cellular metabolism.  Certain algae strains were more tolerant than others.  The overall reduction of TAN from 800 to 5 ppm demonstrates the potential of microalgae for bioremediation of LL.

  
  Philhower, S. and Wilkie, A.C. (2017). Site-Specific Design for Rainwater Harvesting Systems and Applications. 18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  Availability of clean fresh water is directly related to quality of life.  In the developing world, access to clean fresh water is limited and drilling wells is an expensive solution that is not feasible for most poor communities without external resources.  Rainwater, like groundwater, is typically cleaner than surface water, and harvesting rainwater can be a sustainable solution for water scarcity.  Local rainfall data along with planned usage can be incorporated to design a harvester for optimal storage and water usage.  An independent stand-alone rainwater harvester was designed and constructed to serve as an irrigation supply system for a 2000-square foot garden growing seasonal vegetables.  The surface collection area is 100 square feet, and the system was designed with approximately 300 gallons of intermediate storage.  Typical rainfall patterns in Gainesville, Florida indicate that 2,948 gallons of water will be generated per year which is sufficient for the proposed agricultural land use as long as strategic, intermittent water distribution is applied during dry periods.  Other potentially beneficial uses of this system, particularly for areas with limited resources, include a hygiene station or water supply for a communal latrine.

  
  Walsh, B. and Wilkie, A.C. (2017). Start-up of a Small-Scale Anaerobic Digester.  18^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 23, 2017.

  Poster

  Abstract:

  Anaerobic digestion involves the fermentation, breakdown, and stabilization of organic materials in the absence of oxygen, resulting in renewable fuel (biogas) and solubilized nutrients (biofertilizer).  The process design can be relatively simple and inexpensive, with minimal maintenance.  A small-scale (55-gallon) anaerobic digester was designed and constructed for treating food wastes.  The purpose of the self-contained unit is to generate cooking fuel and produce organic biofertilizer for gardening.  Organic loading rates (2g COD/L/day) were established for two primary feedstocks, namely sweetpotato culls and spoiled ground corn.  Critical operational parameters including pH and temperature were monitored closely during the start-up period, and the biogas yield and composition were measured daily to determine methane productivity.  Temperatures were in the mesophilic range, while the pH decreased from 6.61 to 6.16 on day 4 due to increased volatile fatty acid production.  The total biogas production followed the pH trend during the start-up phase and reached steady-state conditions by day 5, producing approximately 34 L biogas/day.  The methane composition of the biogas consistently increased over time, reaching 40% by day 9.  This small-scale, low-cost digester design promotes recovery of methane gas and biofertilizer from food waste, and facilitates diversion of organic residues from landfills.

• 2016 Spring CUR Undergraduate Research Symposium

  Curtis, J. and Wilkie, A.C. (2016). Postharvest Storage Potential of Industrial Sweetpotato Roots and Culls.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  A year-round feedstock for biofuel production would be advantageous for Florida as a replacement crop for citrus groves lost to citrus greening.  The CX-1 sweetpotato is a white-fleshed, high-starch cultivar specifically bred for ethanol production.  The culls, defined as roots that have been damaged by disease or pests, could be used for energy recovery via anaerobic digestion.  The objective of this research was to evaluate the postharvest storability of CX-1 roots and culls.  Samples were prepared at harvest and six months after harvest and characterized for total solids (TS), volatile solids (VS), chemical oxygen demand (COD), starch, and methane potential (culls only).  All analyses were conducted in triplicate, according to Standard Methods.  Methane index potential (MIP) batch assays were conducted for 30 days at 35˚C, in triplicate.  The starch content in the roots was conserved after six months of storage.  The freshly harvested culls reached 100% of their theoretical methane yield, while the stored culls only reached 82%.  The CX-1 roots are an ideal year-round feedstock for bioethanol production considering their high starch content and storability, and the culls are a valuable co-product that could be efficiently digested for methane production immediately following harvest.

  
  Dundar, C. and Wilkie, A.C. (2016). Methane and Nutritional Potential of Industrial Sweetpotato Vine Components.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  In the southeastern United States, an industrial sweetpotato (CX-1) has the potential for utilization as an energy crop for bioethanol production.  The sweetpotato vines are an agronomic co-product that is usually discarded.  The vines can be harvested for animal feed or anaerobically digested to generate biogas.  In order to maximize the energetic and nutritional value of the vines, the different components (leaves, petioles, and stems) were evaluated separately.  The components were characterized for total solids (TS), volatile solids (VS) and chemical oxygen demand (COD).  The ultimate methane potential for each component was measured using methane index potential (MIP) batch assays conducted for 30 days at 35˚C, in triplicate.  Crude protein (CP) and fiber were determined to evaluate vine suitability for animal feed.  Of the three components, the sweetpotato petioles had the highest methane yield (310 L CH₄/kg VS) and should be utilized extensively for energy production.  The leaves contained the highest concentrations of CP (25.7 ± 0.2% DM), even higher than spinach, and thus are better suited for livestock or human consumption.  These findings have important implications for complete utilization of sweetpotato vines, regardless of whether the roots are grown for consumption in the developing world or as biofuel crops in the US.

  
  Fiestas, C. and Wilkie, A.C. (2016). Student Compost Initiative in Peru.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  Municipal solid waste (MSW) is a global dilemma that must be managed properly by local governments and residents.  Lima, the capital and largest city of Peru, houses 8.8 million people who generate nearly 6,000 tons of MSW per day.  Although there is a well-established recycling market for plastics, paper and metals, food waste is often discarded.  Most disposal sites consist of unlined open pits that pollute the air and water, and threaten the health of residents. To alleviate these burdens and promote sustainability, a compost initiative is underway at “Dos de Mayo” school in Callao.  This involves the construction, organization and implementation of an on-site composter, where food waste will be collected from both kitchen preparations and unfinished meals in the cafeteria.  Elementary-age students as well as faculty will better understand the benefits of composting and growing their own organic gardens.  Students will learn how to reduce their ecological footprints and will extend this knowledge to their families and local governments, laying the foundation for a more sustainable future for Peru.  This project is modeled after the UF-IFAS Student Compost Cooperative (SCC) and inspired by the valuable lessons learned as SCC Coordinator at the Bioenergy and Sustainable Technology Laboratory.

  
  Hafner, K. and Wilkie, A.C. (2016). Cultivation of Blue-Green Algae on Landfill Leachate.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  There is an increasing challenge to remediate landfill leachate (LL), the liquid waste generated from municipal solid waste landfills.  LL contains high ammonium content and therefore must be collected and treated.  However, current LL remediation methods are expensive and energy intensive.  Through use of photosynthetic filamentous algae, a sustainable and holistic approach can be developed to combine LL remediation with simultaneous algal biomass production for renewable liquid fuel production.  Through this system, both remediation and biodiesel production could potentially overcome the challenge of attaining economic and technical feasibility.  This project tested the capability of Spirulina for growth and remediation of LL.  Four treatment mediums were investigated: Modified Spirulina Medium (positive control), 5% LL, 10 % LL, and 20% LL.  Spirulina cells were exposed to 120 µmol photons/m²/s fluorescent lighting at a 24:0 photoperiod for 5 days.  Algal remediation potential was measured via total ammoniacal nitrogen (TAN) reduction, and algal biomass growth was evaluated by spectrophotometry at 680 nm.  Results confirmed Spirulina’s ability to grow on dilutions of leachate up to 10%, with final biomass dry weights of 0.89 g/L (5% LL) and 0.80 g/L (10% LL) compared to 1.93 g/L for the control, and 99% TAN removal for both leachate treatments.

  
  Jones, G. and Wilkie, A.C. (2016). Effect of Abscisic Acid on Chlorella vulgaris Growth and Lipid Yield.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  Photosynthetic algae can produce carbon-neutral fuel through lipid transesterification and can be farmed without competing with food crops.  Commercial-scale use of algae for biofuel production is dependent on high lipid yields and efficient extraction.  The purpose of this research was to evaluate the effect of exogenous plant hormones, specifically abscisic acid (ABA), on algal biomass growth and lipid content.  ABA plays an important role in plant responses to environmental stress.  Chlorella vulgaris, a microalgae strain capable of lipid production, was grown in BG-11 standard growth media.  Cultures were illuminated at 300 µmol photons/m²/s on a 12:12 photoperiod.  ABA was added in various concentrations from zero (control) to 20 ppm, and all treatments were performed in triplicate.  Biomass growth rate was measured by spectrophotometry at 680 nm.  Lipid content was determined using nuclear magnetic resonance and presence of lipids was confirmed qualitatively using Nile Red staining.  Compared to the control, there were no significant changes in biomass growth rate or dry biomass yield.  Although ABA did not appear to elicit cell growth, the average lipid yield of all treatments exceeded that of the control.  Further studies are warranted to precisely determine the effect of ABA on microalgae growth and lipid content.

  
  LaPierre, G.D. and Wilkie, A.C. (2016). Opportunity Feedstocks for Biogas Production. 17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  In 2012, the International Energy Agency estimated the world’s electricity consumption at 155,505 terawatt-hours (TWh), with most (80%) generated from fossil fuels.  Thus, worldwide carbon dioxide emissions are rising, making the search for affordable renewable energy sources a prime interest for society.  The production of biogas (methane) from anaerobic digestion of organic matter is receiving renewed attention.  The objective of this research was to determine the methane yield from two potential feedstocks: rabbit manure and Spanish moss (Tillandsia usneoides).  The feedstocks were collected locally, dried at 60˚C for 72 hours and ground to 1 mm with a Wiley mill.  Fresh samples were analyzed for dry matter (DM) and organic matter (OM) according to Standard Methods.  Chemical oxygen demand (COD) was measured to determine a theoretical methane yield potential for each feedstock.  Methane index potential (MIP) batch assays were conducted at 35°C for 30 days, in triplicate.  Methane yields for rabbit manure (207 L CH₄/kg COD) and Spanish moss (165 L CH₄/kg COD) reached 59% and 47% of their theoretical methane yield, respectively, within 30 days.  Rabbit manure and Spanish moss are suitable feedstocks for anaerobic digestion and could serve as co-digestion feedstocks in local biogas applications.

  
  Peralta, M.D. and Wilkie, A.C. (2016). Evaluating a Plant-based Flocculant for Microalgae Biomass Harvesting.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  Establishing new feedstocks for renewable fuel is necessary to lessen our dependence on fossil fuels and mitigate global climate change.  Energy crops for fuel production often displace opportunities for growing food, thereby increasing food prices.  Cultivating microalgae for biofuel production is an innovative solution that does not compete with food crops.  However, harvesting microalgae can be expensive and energy intensive.  The press cake remaining after oil extraction from Moringa oleifera (MO) seeds has been used as a flocculant to purify water, and this non-toxic organic substance can displace expensive chemical additions.  The research objective was to determine the effect of increasing MO concentrations on the flocculation of two different species of algae, Chlorella minutissima and Scenedesmus sp.  Flocculation efficiency was evaluated in triplicate by measuring the optical density of the cultures before and after MO addition using spectrophotometry at 680nm.  Aluminum sulfate (1% w/v) was used as a positive control to compare with increasing dosages of MO flocculant (0.05, 0.50, 1.0, and 1.5 g/L).  Results demonstrated a positive correlation between increasing MO dosages and flocculation efficiency.  A maximum flocculation efficiency of 91% was achieved with 1.5 g/L MO for Chlorella minutissima while only 40% efficiency was achieved for Scenedesmus sp.

  
  Philhower, S. and Wilkie, A.C. (2016). Backyard Biogas Production.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  Anaerobic digestion is a biological process in which organic matter is converted into biogas by microbes in the absence of oxygen.  Biogas can be made from any type of organic biomass and applications range from rural household digesters to industrial-scale systems at livestock farms and wastewater treatment facilities.  The purpose of this research was to evaluate common feedstocks, such as grass clippings, live oak leaves, and chicken manure.  Fresh samples were analyzed for dry matter (DM) and organic matter (OM) according to Standard Methods.  Fresh samples were dried and ground to 0.85 mm using a Wiley Mill for methane index potential (MIP) batch assays conducted at 35˚C, in triplicate.  Chemical oxygen demand (COD) was measured to determine a theoretical methane yield potential for each feedstock.  Methane yields for chicken manure (166 L CH₄/kg COD) and grass clippings (169 L CH₄/kg COD) reached 48% of their theoretical methane yield within 30 days.  Although live oak leaves had similar COD concentrations as grass clippings, their methane yield was extremely low, likely due to their waxy leaf surface and tannic acid content.  Grass clippings and chicken manure are suitable feedstocks for anaerobic digestion, whereas live oak leaves are best suited as a bulking agent for aerobic composting.

  
  Sanchez, C. and Wilkie, A.C. (2016). Bioenergy Production Potential from Small Ruminant Manure.  17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  Goats and sheep are widely reared on small farms in Florida since they require less land and feed than larger livestock, making them easier and less expensive to maintain.  Their pellet-form manure facilitates materials handling – it can be easily collected and stored as solid material.  The manure can be digested anaerobically to recover a sustainable, renewable energy source (methane).  The nutrients remaining in the post-digestion effluent can also be land applied as an organic fertilizer.  The objectives of this study were to characterize each manure type and determine their ultimate methane yields.  Fresh sheep and goat manure pellets were collected locally and characterized for dry matter (DM), organic matter (OM), and chemical oxygen demand (COD).  Methane index potential batch assays were conducted on the manure slurries at mesophilic temperature (35°C) for 40 days, in triplicate.  Goat manure had higher DM and OM contents, resulting in a higher methane yield from goat (7.1 L CH₄/lb) versus sheep (5.1 L CH₄/lb) manure on a fresh weight basis.  The goat manure reached 46% of its theoretical methane yield on a COD basis while sheep manure reached 42%.  Future work will measure the nutrients in the liquid effluent to assess its biofertilizer value.

  
  Vasilevsky, M. and Wilkie, A.C. (2016). Collective Campus Composting at the Student Compost Cooperative. 17^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 24, 2016.

  Poster

  Abstract:

  The Student Compost Cooperative (SCC) is a cross-disciplinary outreach program established by Dr. Ann Wilkie (Soil and Water Science Department, UF-IFAS) that fosters sustainability and nutrient upcycling through composting and sustainable gardening.  The SCC hosts demonstrations and hands-on activities, promotes collaboration among other on-campus organizations, and seeks to popularize sustainability and composting through social media.  The SCC also provides free garden plots for students that lack access to adequate space, while encouraging them to compost their food waste and use the finished product for their own organic gardens.  Composting is a natural decomposition process in which organic wastes decompose into a nutritious soil amendment.  Students learn to accelerate this process through appropriate nutrient ratios of carbon (leaves, twigs, cardboard) to nitrogen (food waste).  The mixture is turned to allow oxygen to reach the aerobic microbial organisms that break down the organic matter.  The advantages are substantial, from the reduction of commercial fertilizer use, to improving soil health, and preventing nutrient leaching.  The SCC is located at Dr. Wilkie’s BioEnergy and Sustainable Technology (BEST) Laboratory.  All UF students and staff are invited to participate in the SCC to make this campus a more sustainable and interactive community of collective composters.

• 2015 Spring CUR Undergraduate Research Symposium

  Bank, M.P. and Wilkie, A.C. (2015). The Effect of Glycerol Addition on Growth of Scenedesmus in Landfill Leachate. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Microalgae have a rapid growth rate and possess the ability to accumulate intracellular lipids. Algae also have significant potential for wastewater bioremediation. Algae can be grown in three modes: autotrophic using light energy, heterotrophic using organic carbon sources, or mixotrophic using a mixture of both. Currently, heterotrophic and mixotrophic growth of algae is limited primarily due to the cost of procuring an organic carbon source. Glycerol is a waste by-product of biodiesel production. This resource could potentially be utilized as a carbon source to grow algae. The objective of this research was to investigate the effect of crude glycerol addition on biomass growth and lipid content of algae grown in landfill leachate. Scenedesmus cf. rubescens, a locally isolated strain with demonstrated ability to produce lipids, was selected as the test organism. Scenedesmus cf. rubescens was grown in Bold’s Basal Medium. Algal growth experiments were conducted in 125 ml Erlenmeyer flasks (100 ml active volume). Subcultures were inoculated with exponentially growing mother cultures at a volumetric ratio of 20% (v/v). Cultures were illuminated at 300 µmol photons/m²/s on a 12:12 photoperiod. All experimental trials were conducted in triplicate. Algal growth was monitored by spectrophotometry using absorbance at 680nm.

  
  Chavez, N. and Wilkie, A.C. (2015). Investigating the Methane Potential of Sweetpotato Culls.  16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Sweetpotatoes can be grown for human consumption (table variety) or as a feedstock for bioethanol production (industrial variety). Industrial-type sweetpotatoes are generally drier with higher starch and less sugar contents than table sweetpotatoes. Whether grown for human consumption or biofuel production, agricultural residues such as culls (rotten or damaged sweetpotatoes) are generated during harvest. Cull rates for sweetpotatoes are generally 30% of the overall crop yield, and thus culls represent excess biomass that can be anaerobically digested for methane production. Anaerobic digestion is an effective means of converting organic matter into methane in an oxygen-free environment. The objective of this research was to determine the methane potential of culls from a common table variety (Beauregard) and an industrial-type (CX-1) sweetpotato. Methane index potential (MIP) batch assays for both types of culls were conducted at mesophilic (35ºC) temperature, in triplicate. The positive controls for the MIP assays included glucose, cellulose and starch. The results indicated that the Beauregard culls had twice the soluble sugar content of the CX-1 variety and were easily biodegraded. The methane production from the Beauregard culls reached 95% of the theoretical methane yield after 22 days, and followed the trend of the glucose control.

  
  Costa, L.C. and Wilkie, A.C. (2015). The Effect of Particle Size on Methane Potential of Sugarcane Bagasse. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Agricultural residues can be used to produce second-generation biofuels. However, their woody texture presents challenges to biodegradation. Sugarcane bagasse is a lignocellulosic residue that can be converted into bioethanol, but requires extensive pretreatment with high temperature, pressure and chemical additions for effective fermentation. Anaerobic digestion is an alternative conversion technology that produces methane gas, but also has limitations with lignocellulosics. The initial conversion of complex biomass into simple sugars (i.e. hydrolysis) is considered the rate-limiting step because the lignin component prevents microbial access to the degradable fractions of the feedstock. The objective of this research was to determine the impact of particle size on methane production from sugarcane bagasse. Sugarcane bagasse was dried and milled to two particle sizes (2mm and 0.85mm). Methane index potential batch assays were conducted at mesophilic (35ºC) temperature, in triplicate. Positive controls with glucose and cellulose reached 98% and 91%, respectively, of the theoretical methane yield, demonstrating the efficacy of the inoculum. The average methane production from sugarcane bagasse only reached 57% of the theoretical yield, emphasizing restricted hydrolysis from the presence of lignin. However, minimal pretreatment, 2mm to 0.85mm particle-size reduction, increased methane production from sugarcane bagasse by 9% over a 20-day digestion period.

  
  Fiestas, C.N. and Wilkie, A.C. (2015). Spoils to Soils Project at the Student Compost Cooperative. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Organic wastes such as food waste, spoiled fruits and vegetables, garden wastes, and yard trimmings can become a nutrient-rich soil amendment, known as compost, which can be used in agriculture, horticulture and urban gardening. Composting is the natural process by which a consortium of aerobic organisms degrades organic matter into a fine humus material. Several factors contribute to successful composting including small particle size, appropriate moisture and temperature conditions, oxygen provided from consistent mixing, and a nutrient balance between carbon and nitrogen. The Student Compost Cooperative (SCC) is a multidisciplinary campus outreach program established by Dr. Ann Wilkie (Soil and Water Science Department, UF-IFAS) that encourages resource conservation and nutrient recycling through hands-on experience with composting and sustainable farming. The SCC operates a composting facility at the BioEnergy and Sustainable Technology Laboratory, where students can drop off their food scraps and receive finished compost in exchange. The benefits of composting are far-reaching. Not only does compost enrich the soils with organic matter and improve water retention, it also significantly reduces organic waste sent to landfills and the use of commercial fertilizers, thereby reducing our reliance on fossil fuels and paving the path toward a sustainable future.

  
  Hafner, K.D. and Wilkie, A.C. (2015). Cultivation of Spirulina for Maximum Biomass Yield. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Algae are high-yielding plants and a potential alternative to conventional fossil fuels that can alleviate the greenhouse effect while simultaneously treating wastewater and producing biomass for biodiesel and food. The objective of this study was to identify optimal cultivation methods for maximum biomass yield of Spirulina, a filamentous cyanobacterium. Spirulina was cultivated in Modified Zarrouk’s Medium with sodium bicarbonate as the carbon source and sodium nitrate as the nitrogen source. Subcultures were prepared with 10% inoculum in 1L flasks (500 mL active volume). Cultures were illuminated at 250 µmol photons/m²/s on a 12:12 photoperiod. Algal growth was monitored by spectrophotometry using absorbance at 680nm. The effect of culture vessel geometry on biomass growth was evaluated. Results indicated that biomass growth rate was higher using a Luer flask (12.2 mg/L/h) compared to an Erlenmeyer flask (8.4 mg/L/h). The high biomass yields for the Luer flask were likely due to better light penetration into the growing culture because of the greater surface-to-volume ratio. The effect of mixing strategy was also evaluated. Using a Luer flask, mechanical shaking and aeration mixing gave similar biomass growth rates of 12.2 and 12.7 mg/L/h, respectively. Mechanical shaking, however, has the distinct advantage of reduced ammonia stripping.

  
  Nelson, B.S. and Wilkie, A.C. (2015). The Effect of Exogenous Phytohormones on Algal Growth. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Microalgae are potential feedstocks for biofuels because of their fast growth rate and ability to produce lipids. One challenge for commercial-scale algal biofuels is the manipulation of algae to create high lipid content without adversely affecting biomass growth. The objective of this research is to investigate the effect of exogenous plant hormones on algal biomass growth and lipid content. Plant hormones are signal molecules that regulate plant growth and development. Chlorella ellipsoidea, a locally isolated strain with demonstrated ability to produce lipids, was selected as the test organism. Chlorella ellipsoidea was grown in BG-11 standard growth medium. Plant hormones of the auxin, cytokinin, and abscisic acid plant hormone classes were added, individually and in combinations, to determine their influence on cell biomass and lipid content. All experimental trials were conducted in triplicate. Preliminary trials have shown that all hormone treatments outperformed the control, and algae grew faster in all hormone combinations than in individual hormone treatments. The combination of trans-zeatin riboside (1 ppm), 1-naphthaleneacetic acid (5 ppm), and abscisic acid (5 ppm) exhibited the fastest growth rate. Among individual hormone treatments, the fastest growth rate was achieved by abscisic acid at a concentration of 50 ppm.

  
  Nesralla, L.R. and Wilkie, A.C. (2015). Evaluating the Nutritional Value of Sweetpotato Vines for Animal Feed.  16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Sweetpotato, Ipomoea batatas L. (Lam.), is a highly nutritive crop grown in many developing countries. Sweetpotato is advantageous because of its rusticity, low maintenance and high adaptability to extreme conditions such as droughts and flooding. Sweetpotato roots can be used for human food and vines for livestock feed. Indeed, the fresh vine yield often exceeds the root yield on a per hectare basis. However, the valuable potential of the vines as animal feed is often overlooked. The objective of this research was to evaluate the nutritional value of ensiled sweetpotato vines. Ensiling preserves vine quality by storing the vines under anaerobic conditions and stimulating acid fermentation. Fresh and ensiled vine characteristics, including dry matter, fermentative capacity, crude protein (CP), neutral/acid detergent fiber (NDF/ADF) and lignin, were assessed for different sweetpotato cultivars. The effect of the wilting period on the fermentation process was also evaluated. When compared to the same cultivars of fresh vines, the ensiling process preserved the average CP and NDF concentrations. Ensiled sweetpotato vines can be a highly nutritious, low-cost alternative to grain-based feeds to support livestock in less productive periods of the year when pastures are not available.

  
  Spaulding, A.B. and Wilkie, A.C. (2015). Solar Disinfection of Anaerobic Digester Effluent from Human Waste Treatment. 16^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 18, 2015.

  Poster

  Abstract:

  Anaerobic digestion (AD) is a biological method of treating organic waste in the absence of oxygen. Benefits of a controlled AD system include production of renewable energy (biogas) and a nutrient-rich digested effluent that can be land applied as a biofertilizer for agriculture. Efforts to use AD to help developing countries improve sanitation and increase crop and renewable energy production are ongoing. However, when AD is applied to treat human waste, harmful parasites can persist in the digestate, posing a potential health hazard. The purpose of this project was to develop and evaluate a disinfection stage to follow the AD process: solar sanitation. The conceptual design consists of piping the digestate to holding tanks and harnessing solar energy for thermal inactivation. Temperature conditions necessary for parasite inactivation were determined using Ascaris as a model organism since it is among the most resilient and prevalent parasitic helminths in many developing countries. Plastic tanks were filled with water as the test medium, painted black for maximum solar gain, and fitted with solar reflectors and temperature data loggers. The tanks were evaluated in various sizes and temperatures above 50ºC were attained for sufficient time to inactivate the model parasite.

• 2014 Spring CUR Undergraduate Research Symposium

  Lovato, T.B. and Wilkie, A.C. (2014). Cultivating Algae on Cellulosic Ethanol Stillage. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Poster

  Abstract:

  Cellulosic ethanol is a potential alternative to petroleum-based fuels and, because it is created from lignocellulose found in woody plant materials, it does not compete directly with food production, unlike corn-based ethanol.  One obstacle in cellulosic ethanol production is dealing with the stillage by-product that is typically high in nutrients and chemical oxygen demand.  Growing algae for biofuels and high-value pigments requires high nitrogen inputs to sustain growth and produce more biomass, providing a possible bioremediation option for stillage.  The objective of this study was to cultivate algae using stillage as a nutrient source.  Sugarcane bagasse stillage from the UF-IFAS Stan Mayfield Biorefinery Pilot Plant was characterized.  A strain of microfilamentous cyanobacterial algae, Spirulina sp., was isolated using standard culture medium, then inoculated into flasks with 2% dilutions of stillage supplemented with Spirulina nutrients.  The experimental group using the 2% stillage dilutions produced more biomass than the control under the same conditions, as measured by optical density.  Lipid analysis using nuclear magnetic resonance showed that the algae biomass had low oil content and was not ideal for biodiesel production.  However, the biomass growth under experimental conditions points towards a potential use of stillage as a nutrient source in algae production.

  
  Spaulding, A. and Wilkie, A.C (2014). The Student Compost Cooperative and Nutrient Recycling Education. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Poster

  Abstract:

  Too often organic by-products are needlessly wasted.  Paper, plastic, metal, and glass are not the only materials that can be recycled – foodscraps can be easily managed to return essential plant nutrients to our production system.  The process of composting compiles decomposing organic matter to create a rich soil amendment that can be used in agriculture, horticulture and urban gardening.  Composting is a sustainable practice that can decrease reliance on commercial fertilizers which are produced using huge inputs of fossil fuel.  Nutrients vital to plant growth are routed back to their sources, instead of being deposited in landfills.  The Student Compost Cooperative (SCC) is a campus outreach program established by Dr. Ann C. Wilkie (Soil and Water Science Department, UF-IFAS) that encourages responsible resource cycling through hands-on education and practical demonstration.  The SCC practices the various methods of composting through a simple exchange: drop off foodscraps at the BioEnergy and Sustainable Technology Laboratory and take home finished compost that can be used for vegetable gardens and potted plants.  By teaching the basic principles of composting, the SCC promotes sustainable resource cycling habits that can be implemented by anyone, anywhere.

  No poster available:

  Andrilenas, J. and Wilkie, A.C. (2020). Computer-Vision Estimation of Insolation from Satellite Imagery.  2020 Spring Undergraduate Research Symposium, University of Florida, Gainesville, Florida, April 2, 2020.

  Abstract:

  Knowledge of an area’s insolation (the solar radiation it receives) is essential to choosing plantings, especially in the context of urban gardens where insolation may vary drastically within a relatively small area.  Planting appropriately based on insolation is vital to the success of a garden.  Plants that require full sun should be in areas with full sun, while plants that prefer shade should be in areas with less sun.  This project measured insolation at the BioEnergy and Sustainable Technology (BEST) Laboratory field research and demonstration area at the University of Florida in Gainesville, Florida.  First, a computer-vision algorithm was used to estimate insolation and create an approximate insolation map for the area based off satellite imagery.  Second, an open-source, low-cost GPS-enabled light meter and data logger were used to quickly obtain insolation data for the area and ground-truth the approximate insolation map generated from imagery.  The combination of these tools will allow more efficient plantings to maximize success and yields and minimize wasted time and effort at the research site.  Additional benefits from these tools are easy and low-cost siting information for shade trees or solar devices to maximize building energy efficiency or power generation, respectively.

  
  Dominguez, N.M. and Wilkie, A.C. (2014). Dairy Lagoon Effluent as Growth Medium for Indigenous Algae. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Abstract:

  Increased fossil fuel use has accelerated climate change, presenting broad future challenges.  Furthermore, as developing nations experience growth, they will demand more animal products.  Consequently, the world demand for energy and food will increase.  This increased demand for livestock agriculture has the potential to release nutrients into the environment that will require remediation.  These global challenges can be addressed locally using microalgae.  Indigenous algae can be used as a tool to remediate waste from industrialized agriculture.  A Chlorella-like organism (sp. ACW1) was cultivated using dairy lagoon effluent as a growth medium.  Cultures of Chlorella sp. ACW1 were grown in 50% and 100% wastewater.  Total ammoniacal nitrogen was completely remediated in the 100% wastewater after 72 hours.  Furthermore, this alga has a 15% neutral lipid content that can potentially be used as a sustainable third-generation biofuel.  The cultivation of indigenous algae with characteristics that allow the organism to thrive in agricultural wastewater presents an alternative to fossil fuel use and a bioremediation solution for agricultural wastewater.

  
  Kanner, S.I. and Wilkie, A.C. (2014). Using a Multimeter to Measure Compost Moisture Content. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Abstract:

  Many factors contribute to a healthy compost pile and can make or break the success of a pile if overlooked.  Moisture has a direct effect on pile aeration and pile temperature.  The ideal range for compost moisture is 40%-60%.  However, current tools for reliably checking the moisture content of soil/compost are expensive and out of the price range for most home gardeners.  The purpose of this study was to develop a simple, accurate, and inexpensive method for testing the moisture content of a home compost pile.  An experiment was designed to determine moisture content using an inexpensive construction moisture meter designed for testing wood and mortar and by correlating moisture content with the resistance readings of a home multimeter.  Compost samples were oven-dried and water was added incrementally.  Samples were tested using the moisture meter and the multimeter, at 10% moisture increments.  The construction moisture meter proved reliable up the 50% range.  A clear correlation was observed between resistivity and moisture using the multimeter above the 50% moisture mark.  The ability to use a multimeter to reliably measure soil/compost moisture would make the process of checking moisture content more attainable for the home gardener.

  
  Lee, C.A. and Wilkie, A.C. (2014). Cultivating Spirulina on Landfill Leachate. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Abstract:

  Landfill leachate is a wastewater that contains a high concentration of nutrients such as nitrogen and phosphorous.  The objective of this study was to investigate the potential of algae for bioremediation of landfill leachate.  The microalgae, Spirulina, was selected for experimentation due to its high pH tolerance and its filamentous structure which facilitates harvesting.  A culture of Spirulina was grown in a medium consisting of a 10% dilution of landfill leachate and 90% of an optimal Spirulina medium in order to acclimate the culture to landfill leachate.  A subculture was subsequently used as inoculum for the experimental work.  Three treatments were examined in triplicate: a biotic control, an abiotic control, and a 20% dilution of landfill leachate inoculated with Spirulina.  Treatments were exposed to alternating 12 hour shifts of fluorescent light at 351.5 μmol photons/m²/sec for 48 hours.  Every 12 hours, measurements were taken to determine optical density, electrical conductivity, pH, and total ammoniacal nitrogen.  This study shows that Spirulina cultures can survive in landfill leachate.  Further studies are needed to optimize culture growth and realize bioremediation potential.

  
  Shoelson, A.S. and Wilkie, A.C. (2014). Cultivation of Haematococcus pluvialis and Production of Astaxanthin. 15^th Annual Undergraduate Research Symposium, University of Florida, Gainesville, Florida, March 27, 2014.

  Abstract:

  Haematococcus pluvialis is a freshwater species of Chlorophyta from the Haematococcaceae family.  When stressed, the cells encyst into immobile aplanospores and accumulate astaxanthin, a carotenoid pigment.  Astaxanthin has strong antioxidant properties and offers a wide range of health benefits.  It is therefore highly sought after and is used heavily in the aquaculture and pharmaceutical industries.  However, because it can be difficult to obtain from natural sources, synthetic substitutes are often used that lack many of the benefits natural astaxanthin provides.  The objective of this study was to optimize the growing conditions of Haematococcus along with stressing the cells to produce astaxanthin and determine a way to extract it.  Haematococcus pluvialis was cultivated using a variety of techniques and conditions.  An orbital shaker with volvox media proved to have the most optimal conditions of those tested.  Haemoatococcus cells were stressed into producing astaxanthin by being put under high light and low nutrient conditions.  The production of Haematococcus and astaxanthin on wastewaters, such as that from aquaculture, can offer enormous benefits by using the algae in fish feed, allowing the health benefits to be passed on to the consumer.