College of Agriculture & Natural Resources

Permanent URI for this communityhttp://hdl.handle.net/1903/1598

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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2007 - 200912010 - 20121

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Subject: search.filters.subject.Emergy

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    ENVIRONMENTAL SUSTAINABILITY AND WASTE TREATMENT CAPABILITIES OF SMALL-SCALE ANAEROBIC DIGESTION SYSTEMS
    (2012) Moss, Andrew Robert; Lansing, Stephanie A.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Anaerobic digestion is a common form of waste treatment and energy production throughout the world, and in the United States the number of agricultural digesters is increasing at a rate of approximately 10% annually. As the number of digesters grows, efforts to assess the environmental cost of their installation and the potential utility of their by-products are required. This research investigates the relative environmental sustainability of small-scale digesters treating dairy manure in the U.S. and human waste in Haiti, and explores the biogas potential and nutrient transformations resulting from the anaerobic digestion of dairy manure. Specifically, the objectives of the research are: 1) to conduct an eMergy analysis on the two digestion systems to assess the effect of waste source, climate, and infrastructure on system sustainability; and 2) to provide an overview of waste treatment and energy production options for agricultural digesters treating dairy manure in the United States.
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    Integrated Energy, Environmental and Financial Analysis of Biofuel Production from Switchgrass, Hybrid Poplar, Soybean and Castorbean
    (2007-01-22) Felix, Erika Ruth; Tilley, David R; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Biofuels are considered a substitute for petroleum-fuels, but to be viable they should not depend heavily upon non-renewable resources. The objective of this study was to estimate the ultimate amount of energy required to produce liquid-fuels from switchgrass, hybrid poplar, soybean, and castorbean. Emergy (with an "m") accounting was used to integrate all environmental, fossil fuel, and human-service inputs used throughout the production chain from agricultural field to processing facility. Depending on feedstock type and conversion yields, environmental inputs were between 21-44%, fossil fuels were 18-73% and human-derived services were 2-61%. Gallons of transportation fuel produced per gallon of petroleum used ranged from 0.06 to 4.2 for ethanol and 2.6 to 4.4 for biodiesel. No biofuel was made with less than 75% non-renewable resources. Energy embodied in "hidden" indirect paths ranged from 38-99%. The viability of replacing petroleum with cellulosic ethanol or biodiesel is highly questionable.