No description available.

No description available.

Ex-situ bioremediation of saturated soil contaminated with pentachlorophenol and 2,3,5,6-TeCP is commonly accomplished by landfarming or by treatment in a bioreactor. Treating saturated, low-permeability soils in bioreactors, without pre-treatment requires a reactor capable of promoting anaerobic and/or aerobic removal of chlorophenols without transferring these contaminants to the aqueous phase. A pilot-scale bioreactor was designed to treat 3.7 cubic meters of contaminated soil with a saturated hydraulic conductivity of 0.12 cm/day. The bioreactor demonstrated significant removal of chlorophenols when soil was infused with a treatment mixture containing imitation vanilla flavoring as an electron donor for reductive dechlorination and primary substrate for aerobic cometabolism. Bench scale studies showed greater overall removal when feed mixtures included an inoculated biomass, or when treatment mixtures were maintained anaerobically prior to use. The combined results of these studies suggest that concentrations of pentachlorophenol and 2,3,5,6-TeCP in soil can be significantly reduced using fill and draw batch reactors, operated for three to five week long cycles, using a variety of treatment mixtures. / Graduation date: 1998

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Donald L. Sparks, Dept. of Plant & Soil Science. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2002. / Title from first page of PDF file. Document formatted into pages; contains xv, 179 p.; also contains graphics (some col.). Includes abstract and vita. Advisor: Franklin W. Schwartz, Dept. of Geosciences. Includes bibliographical references (p. 172-179).

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xv, 160 p.; also includes graphics. Includes abstract and vita. Advisor: Warren A. Dick, Environmental Science Graduate Program. Includes bibliographical references (p. 135-160).

No description available.

The chelating agent ethylene diamine tetraacetic acid (EDTA) is promising. The ligand is more effective in removing the metal contaminants from soils than HCl. In a batch experiment, EDTA released a large portion of metals from soils to soil extracts. A batch method was also developed for recovering the metal contaminants in the resulting EDTA soil-extracts. Using an anion exchange resin (AER) AG 3-x4, up to 99% of the Cd, Cu, Pb, and Zn were removed from the leachates. / To increase the efficacy of the extraction method we tested different reagent, amount, and technical application strategies using soil columns. Mixing the reagent with the whole soil column was found to be the most efficient method for the application of the chelating agent for the purpose of metal extraction from soils. It was found that EDTA was superior to citric acid in removing Cd, Cu, Pb, and Zn from the soils investigated. Up to 27% more Cd, 23% more Cu, 42% more Pb, and 21% more Zn were removed by the EDTA and the removal was further increased with the addition of an acid/salt solution (1.0 M HCl and 1.0 M KCl) to the columns. Other promising results are that the AER in columns is an effective method for extracting metals from EDTA soil-extracts with different properties. The resin column method was found to be more efficient than the resin batch procedure. / The results of the simulated field experiment confirmed that the remediation of contaminated soils can be achieved using EDTA. The majority of the contaminated soils were decreased to the point that they could be reused for commercial and/or residential use. / Computer models can be used to predict the possible metal speciation and interaction with solid surfaces in soils. Using the MINEQL+ program, the models estimated that most of the metal species in the soil extracts (in the presence of EDTA, chloro, hydroxo, and carbonato ligands and humate and hydrous ferric oxide (HFO) solid phases) were present as soluble metal-EDTA complexes. It appears that the metal-EDTA complexes found in the systems are very stable over a wide range of soil pH. Our surface complexation models also indicated that the EDTA is much stronger than the humate and the HFO solid phases in forming complexes with the metals. As a consequence, the adsorption of the Cd, Cu, Pb, and Zn by the solid surfaces was negligible in the presence of EDTA. (Abstract shortened by UMI.)

No description available.

No description available.