Engineering Commons^™

Evaluating And Predicting The Risk Of Algal Blooms In A Freshwater Lake Through A 4-Dimensional Approach: A Case Study On Lake Mitchell, Sumit Kumar Ghosh

Electronic Theses and Dissertations

Excessive algal growth in freshwater lakes can negatively impact ecosystems, recreation, and human health. Though algae are a natural part of freshwater ecosystems, elevated nutrient loading from anthropogenic and natural sources can lead to algal blooms. Both algae and blue-green algae (BGA) are responsible for algal blooms; however, BGA (cyanobacteria) is more dangerous. The first objective of this research was to prepare a conceptual model to understand how various environmental variables affect algae. This conceptual model was used to choose the environmental variables that help increase or decrease algae in the water environment. The second objective was to develop empirical …

Nutrient Limitation Of Algal Growth In Fishery Lakes, Madeline Ludwig

Biological and Agricultural Engineering Undergraduate Honors Theses

This study investigated the effect of nutrient addition on algal growth in three United States Forest Service lakes for fishery management in Arkansas. In fishery managed lakes, fertilization works by manipulating algae growth, a basal food resource in lakes, to promote the growth of the fish population. For the nutrient addition experiments, water was collected from each lake in cubitainers and spiked with nutrients; the treatments included the control, nitrogen (+N), phosphorus (+P), and nitrogen and phosphorus (+N +P). When algal growth was visually observed, a water sample was collected from each cubitainer and analyzed for chlorophyll-α. The results showed …

Chloride Salt Inhibition On Lipid Production In Wastewater-Grown Algae For Biofuel Production, Will Richardson

Biological and Agricultural Engineering Undergraduate Honors Theses

Algae are increasingly being recognized as useful organisms for many applications in today’s world. Their ability to remove nitrogen, phosphorus, and trace metals from water while adding oxygen to water makes them an attractive tertiary treatment technology in municipal wastewater treatment facilities. At the same time, algae produce lipids and carbohydrates that are useful for biofuel production, and they are not a human food crop unlike many biofuel feedstocks. In this study the effect of increased chloride concentrations in wastewater was assessed on the ability of two species of algae, Chlorella vulgaris and Scenedesmus dimorphus, to function as a …

Wafer Enhanced Electrodeionization For Conversion Of Co2 Into Bicarbonate Feed For Algae Cultured Photobioreactors, Kayvan Afrasiabi

Chemical Engineering Undergraduate Honors Theses

The world has acknowledged climate change as a global crisis that demands considerable attention, with one of the largest culprit being carbon emissions from industrial processing and power generation. While reduction in carbon emissions is the principal action towards mitigating the effects of climate change, scientists and engineers have given increased attention to alternative sources of energy as well as methods of carbon sequestration to coax traditional manufactory and industry into environmentally friendly and sustainable practices. One technology of this nature is the use of wafer-enhanced electrodeionization (WE-EDI) membranes to convert gaseous carbon dioxide (CO₂) from industrial flue …

Cultivation Of Chlorella Sorokiniana Using Beef Feedlot Runoff Holding Pond Effluent, Mitchell Klaus Goedeken

Department of Biological Systems Engineering: Dissertations and Theses

A study was conducted to test the suitability of utilizing beef feedlot runoff holding pond effluent for cultivating algae. The algae strain used, Chlorella sorokiniana, was previously identified as a potential energy feedstock for cattle. The previous research was initiated in pursuit of a goal to develop a cycle of utilizing nutrients from beef manure to cultivate algae and then utilizing dewatered algae as a feed supplement for beef cattle.

Runoff holding pond effluent samples were collected from commercial beef production operations in Nebraska during spring 2016. Equal portions of samples from each cooperating farm were composited and then aliquoted …

Reducing Equifinality Using Isotopes In A Process-Based Stream Nitrogen Model Highlights The Flux Of Algal Nitrogen From Agricultural Streams, William I. Ford, James F. Fox, Erik Pollock

Biosystems and Agricultural Engineering Faculty Publications

The fate of bioavailable nitrogen species transported through agricultural landscapes remains highly uncertain given complexities of measuring fluxes impacting the fluvial N cycle. We present and test a new numerical model named Technology for Removable Annual Nitrogen in Streams For Ecosystem Restoration (TRANSFER), which aims to reduce model uncertainty due to erroneous parameterization, i.e., equifinality, in stream nitrogen cycle assessment and quantify the significance of transient and permanent removal pathways. TRANSFER couples nitrogen elemental and stable isotope mass‐balance equations with existing hydrologic, hydraulic, sediment transport, algal biomass, and sediment organic …

Evaluation Of Flocculation, Sedimentation, And Filtration For Dewatering Of Scenedesmus Algae, Nicholas A. Rhea, Jack Groppo, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algae can be used as a feedstock for agricultural fertilizers, livestock and poultry feeds, anaerobic digestion, and biofuel production. For each end product, the requirements for moisture content (or solids content) vary, such that a desirable water removal strategy needs to be adaptable to varying levels of water removal. Flocculation, sedimentation, and filtration were evaluated as possible strategies for thickening and dewatering of algae. The goal of this study was to validate that algae cells treated by such means could be processed by vacuum belt filters and to determine the conditions under which the solids content could be increased to …

Capture And Recycle Of Industrial Co2 Emissions Using Mircoalgae, Michael H. Wilson, Daniel T. Mohler, John G. Groppo, Thomas E. Grubbs, Stephanie Kesner, E. Molly Frazar, Aubrey Shea, Czarena L. Crofcheck, Mark Crocker

Center for Applied Energy Research Faculty and Staff Publications

A novel cyclic flow photobioreactor (PBR) for the capture and recycle of CO₂ using microalgae was designed and deployed at a coal-fired power plant (Duke Energy’s East Bend Station). The PBR was operated continuously during the period May–September 2015, during which algae productivity of typically 0.1–0.2 g/(L day) was obtained. Maximum CO₂ capture efficiency was achieved during peak sunlight hours, the largest recorded CO₂ emission reduction corresponding to a value of 81 % (using a sparge time of 5 s/min). On average, CO₂ capture efficiency during daylight hours was 44 %. The PBR at East Bend …

Evaluation Of Flocculation, Sedimentation, And Filtration For Dewatering Of Algal Biomass, Nicholas A. Rhea

Theses and Dissertations--Biosystems and Agricultural Engineering

Algae can be used as a feedstock for agricultural fertilizers, livestock/poultry feeds, anaerobic digestion, and biofuel production. Regardless of the end product, water removal is necessary and difficult to do cost effectively. For each product the requirements for moisture content (or solids content) vary, such that a desirable water removal strategy would need to be adaptable to varying levels of water removal. Flocculation, with sedimentation and drying was evaluated as a possible strategy for algae dewatering. Anionic and nonionic flocculants are known to be ineffective at flocculating algal culture, which was confirmed for this case by electro-osmotic flow testing of …

Investigation Of The Potential For Algaenan To Produce Hydrocarbon Based Fuels From Algae By Hydrous Pyrolysis, Wassim Adel Obeid

Chemistry & Biochemistry Theses & Dissertations

The use of algae as a feedstock for hydrous pyrolysis has a high potential for producing biofuels. The non-food nature of algae in addition to the various advantages associated with the hydrous pyrolysis process makes this combination for the production of biofuels of high interest. However, current results from algae processing have alluded to some challenges: byproducts arising from the thermal transformation of carbohydrates and proteins, which become incorporated in the oil fraction, result in high oxygen and nitrogen contents of the oil. Accordingly, this produces an oil of low quality for refineries. This dissertation investigates use of a pretreatment …

Pretreatment Of Scenedesmus Sp. Biomass As A Potential Anaerobic Digestion Substrate, Xinyi E, Czarena Crofcheck

Biosystems and Agricultural Engineering Faculty Publications

Algal biomass can be a potential substrate for anaerobic digestion. However, raw algae cells show a resistance to biological degradation, resulting in a slower methane production rate. Varying thermal and chemical pretreatments of algal biomass were investigated in an attempt to increase soluble organic matter (SOM) yield, which would result in enhanced methane production during subsequent anaerobic digestion. Scenedesmus sp. was harvested using three different procedures: with flocculation, with flocculation and drying, and without flocculation or drying. For all pretreatments and algae types, fluorescence micrographs were obtained to visually confirm the degradation of the algal cell walls. A complete 2 …

Influence Of Flue Gas Components On The Growth Rate Of Chlorella Vulgaris And Scenedesmus Acutus, Czarena Crofcheck, Aubrey Shea, Michael D. Montross, Mark Crocker, Rodney Andrews

Biosystems and Agricultural Engineering Faculty Publications

Atmospheric carbon dioxide levels have increased since the industrial revolution due to the increase in combustion of fossil fuels. One possible alternative strategy is the use of microalgae for CO₂ capture and recycling. Major components in coal-derived flue gas that may accumulate and effect algae growth include both sulfur oxides and fly ash. However, in practical application, sulfur oxides will be converted quickly to the acid product (H₂SO₄) in the aerobic aqueous conditions of algae cultivation. In this article, the influence of elevated H₂SO₄ levels and the presence of coal-derived fly ash …

Bioflocculation Of Wastewater Treatment Pond Suspended Solids, Louis Lefebvre

Master's Theses

Bioflocculation of Wastewater Treatment Pond Suspended Solids

Louis Lefebvre

Wastewater treatment lagoons and high rate algae ponds (HRAPs) can provide cost effective wastewater treatment, but they commonly have high effluent concentrations of total suspended solids (TSS). In this thesis algae pond effluent was treated in a beaker testing apparatus (mixed and aerated) with various mixtures of activated sludge and primary effluent simulating differing activated sludge aeration basin compositions then was allowed to settle to assess settleability. Conventionally, microalgal suspended solids are removed by chemical coagulation followed by separation methods that often have a high cost relative to the low cost …

Evaluating Algal Growth At Different Temperatures, Keelin Owen Cassidy

Theses and Dissertations--Biosystems and Agricultural Engineering

In recent years, there has been a concern for the amount of carbon dioxide released into the atmosphere and how it will be captured. One way to capture carbon dioxide is with algae. In this study, algae's growth was measured at different temperatures. The first part of the study was to grow Scenedesmus and Chlorella with M8 or urea growth media at a temperature of 25, 30 or 35ºC. It was found that 30ºC had the best growth rates for both algae. The second part studied Scenedesmus growth with urea, more in-depth, and found the optimum growth temperature to be …

Flocculation Of Wall-Deficient Cells Of Chlamydomonas Reinhardtii Mutant Cw15 By Calcium And Methanol, Matt Scholz, Takanori Hoshino, Mark R. Riley, Joel Cuello

Department of Biological Systems Engineering: Papers and Publications

Flocculation is a common and inexpensive method for harvesting algae from solution. After nitrogen starvation, it was shown that 83 + 3% of the wall-deficient cells of the cw 15 mutant of Chlamydomonas reinhardtii flocculated from 12 mL samples within 15 min after the addition of 15 mM calcium chloride at pH 8.4. Only 24 2% of the wildtype strain flocculated under these conditions, thus demonstrating how a simple mutation might facilitate process design. The data suggested that algae grown in waters with similar calcium concentrations (e.g. certain wastewaters) might be harvested through simple pH adjustment. It was also discovered …

Algae And Biodiesel: Patenting Energized As Green Goes Commercial, Matthew R. Priess, Stanley P. Kowalski

Law Faculty Scholarship

In the twenty-first century, predominant dependence on fossil fuels as energy resources will not be sustainable. Developing and commercializing green energy innovations will be an essential component of the transition to a more diversified energy economy. Algal biodiesel is one of the most promising green fuels because of its potential as a renewable and sustainable fuel source without displacing food crops. Algal biodiesel research and development are necessary early steps towards a transition to a green energy economy. The strategic use of strong patent portfolios will drive this by attracting investment, incentivizing innovation and accelerating commercialization. Whereas algal biodiesel research …