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Diffuser Operations at Spring Hollow Reservoir

by Gantzer, Paul Anthony

Abstract (Summary)
Stratification is a natural occurrence in deep lakes and reservoirs. This phenomenon results in two distinct layers, the warmer, less dense epilimnion on top and the colder, denser, hypolimnion on the bottom. The epilimnion remains saturated with dissolved oxygen (DO) from mass transfer with the atmosphere, while the hypolimnion continues to undergo oxygen-depleting processes. During seasons of high oxygen demand the hypolimnion often becomes anoxic and results in the release of compounds, such as Iron, Manganese, Hydrogen Sulfide, and Phosphorous from the sediment. Iron, Manganese, and Hydrogen Sulfide can require addition Chlorine for water treatment plants, thus increasing cost and the potential production of DBPâs, while the release of phosphorous results in algal blooms the following year. Spring Hollow Reservoir, located in Roanoke County, Virginia is a deep reservoir that undergoes stratification during the summer months. During 1997 Roanoke County purchased a bubble-plume diffuser from Tennessee Valley Authority (TVA) to oxygenate the hypolimnion to maintain long-term water quality. Spring Hollow currently operates the diffuser, with compressed air, during late summer months when DO levels in the hypolimnion reach approximately 4 mg/L. Observations during oxygenation have identified changing DO addition rates during diffuser operation and changing DO depletion rates following termination of oxygenation. Future research should focus on developing a quantitative understanding of the changing rates as they are related to diffuser induced oxygen demand.
Bibliographical Information:

Advisor:Randy Dymond; Dan Gallagher; John Little

School:Virginia Polytechnic Institute and State University

School Location:USA - Virginia

Source Type:Master's Thesis

Keywords:civil engineering

ISBN:

Date of Publication:05/28/2002

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