UMD Theses and Dissertations

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

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Author: search.filters.author.Hamrum, DavidSubject: search.filters.subject.Phosphorus

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    THE EFFECTS OF DRAINAGE DITCH FILTER COMPOSITION ON HYDRAULIC PROPERTIES AND P SORPTION
    (2014) Hamrum, David; Hill, Robert L; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Phosphorus (P) in agricultural runoff is considered a primary contributor to waterway eutrophication. Currently filters made with P-sorbing materials (PSMs) in drainage ditches have been shown to effectively remove P in some situations, but further optimization is necessary. Sorption isotherms were used to determine PSM and temperature effects on P sorption. No effect was found due to temperature, although significant differences were found among the materials used. The different mechanisms of P sorption suggest the retention time used was not suitable for this study. A mesocosm experiment was set up to maximize the flow through filters by mixing gypsum with sand to increase the hydraulic conductivity without sacrificing P sorption. The mixture containing 90% mined gypsum and 10% sand had the highest hydraulic conductivity without a reduction in total P sorption. The mixture containing 80% mined gypsum and 20% sand could have potential as an alternate mixture.