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Assimilation of Sediment-Bound Trace Metals by Marine Bivalves: Biological or Geochemical Controls?EPA Grant Number: U914762
Title: Assimilation of Sediment-Bound Trace Metals by Marine Bivalves: Biological or Geochemical Controls?
Investigators: Griscom, Sarah B.
Institution: The State University of New York at Stony Brook
EPA Project Officer: Broadway, Virginia
Project Period: January 1, 1995 through January 1, 1996
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology
The overall objective of this research project is to develop a scale-up procedure for the gas-lift flotation column (GLFC). The project will be performed in two phases. The objective of phase 1, the hydrodynamic study, will be to determine the effects of column geometry and operating conditions on hydrodynamic parameters. The model system will be CO2 and water. The objective of phase 2, the kinetic study, will be to relate flotation kinetics to column hydrodynamics. Ultimately, the particulate phase that will be recovered will be oil droplets suspended in water.
Froth flotation is an adsorptive-bubble separation process, where dispersed particles are separated from a pulp by adsorption at the bubble-liquid interface. The GLFC is an innovative flotation device developed at the University of Pittsburgh. The GLFC has three novel design features, which improve its separation performance over that of conventional flotation columns. Firstly, a central draft tube is inserted in the column, creating a "loop-flow" pattern, which enhances mixing and particle collection efficiency. Several stages of draft tubes may be installed to improve recovery. Secondly, the frother (a surfactant) is added in the gas phase, which results in reduced frother consumption. Thirdly, carbon dioxide (CO2) is used in place of air as the dispersed gas phase, which has been found to enhance recovery, possibly because of the greater hydrophobicity of the CO2 bubble. The most promising application of the GLFC is to recovery of dispersed oil from wastewater, where initial data indicates superior performance compared to conventional flotation column technology.