Nitrate, arsenic and vanadium are all potential groundwater contaminants. Traditional physical/chemical methodologies are often too technical or expensive for rural environments. Biofiltration has been shown to remove a wide range of contaminants depending on the operating parameters. This research examined the possibility of using the denitrifying bacteria, Paracoccus denitrificans, to remove nitrate, arsenic and vanadium simultaneously from groundwater with varying iron concentrations. During bench-scale testing nitrate concentrations were reduced by up to 73%, even with the metals present. Without iron, arsenic and vanadium removal was insignificant. Removal increased when iron was added as it was found that arsenic and vanadium could be removed adsorptively by iron hydroxides. With 1 mg/L of iron present, removal rates of 67% and 91% were achieved for arsenic and vanadium, respectively. When the iron was increased to 2 mg/L, the removal rates increased to 85% and 96%, respectively.

No description available.

The kinetics of dissolution of titanium and vanadium in liquid steel has been studied. Two periods were distinguished: the steel shell period and the free dissolution period. / In the case of titanium, it is shown that the customary frozen shell of steel encases the cylinder following its initial immersion. Premature internal dissolution then begins as a result of liquid eutectic of Fe(,0.3) Ti(,0.7) composition forming at the inner steel shell boundary. This phenomenon triggers an exothermic dissolution and erosion of the inner steel shell. The net result is considerable shortened shell melting times. During the free dissolution period, the temperature of the titanium dissolving at the interface increases and the dissolution process becomes self-accelerating. / During the steel shell period with pure vanadium and ferrovanadium alloys, no reaction was observed between the steel shell and vanadium. For low grade ferrovanadium alloys, the dissolution proceeds via a heat transfer mechanism. On the other hand, for high grades, ferrovanadium mass transfer mechanisms dominate. / A simplified mathematical model of the process has been developed to describe the coupled heat and mass transfer phenomena involved in the various systems studied.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Proefschrift Rijksuniversiteit Groningen. / Met lit. opg. - Met een samenvatting in het Nederlands.

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. Albert E. Stiegman, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 27, 2004). Includes bibliographical references.

Thesis (Ph. D.)--Columbia University, 1926. / Vita. Bibliography: p. [32].

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Transcript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Tatyana Polenova, Dept. of Chemistry & Biochemistry. Includes bibliographical references.