Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 129-135).

Thesis (M.S.)--University of Southern California, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D. in Chemistry)--University of California, Berkeley, Jan. 1958. / Also issued as UCRL-8059. Includes bibliographical references (leaf 92).

Thesis (M.S.)--University of Southern California, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2006. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 May 23

The presence of wide spectrum antimicrobial agents triclosan (TCS) and triclocarban (TCC) in the environment has become a concern due to the adverse impact on the environment. Montmorillonite, a widely distributed clay mineral in the natural environment, has been used as an obstacle in landfills to avoid contamination of soil and water by contaminants in leachates due to its high surface area, cation exchange capacity, and abundance. The research reported here focuses on understanding the abiotic oxidative transformation of TCS and TCC by Fe(III)-modified montmorillonite. The overall objectives of this work were: 1) to investigate TCS and TCC oxidative transformation kinetics and transformation products in different environmental conditions, and 2) to elucidate their reaction pathways. TCS was reacted with Fe(III)-modified montmorillonite under the following experimental conditions: 1) at 40% relative humidity and room temperature for up to 100 d with and without UV light exposure; and 2) in aqueous environment with different initial TCS concentrations, light exposure, pH levels, and in the presence of natural organic matters. Reaction in the presence of Na- montmorillonite was conducted for comparison with results from TCS reaction in the presence of Fe(III)-modified montmorillonite. In addition, transformation of TCS in the presence of other types of minerals was also investigated. Transformation of TCC on Fe(III) and Na-montmorillonite in an aqueous environment with and without exposure to light was also studied at different initial TCC concentrations. TCS and TCC transformation products were a) characterized using LC/MS, GC/MS, and computational modeling, and b) quantified using HPLC/UV and GC/MS. The main TCS transformation products were 2,4-dichlorophenol, 2,4-dichlorophenol dimer, chlorophenoxy phenols and, TCS dimers and trimers. 2,8-dichlorodibenzo-p-dioxin was identified under UV light and the sun simulator experiments. Formation of 4-chloroaniline and 3,4-dichloroaniline were confirmed as transformation products of TCC. To the best of our knowledge, this is the first time that 4-chloroaniline and 3,4-dichloroaniline were confirmed as abiotic transformation of TCC. This research has generated a better understanding of the abiotic environmental fate of TCS and TCC and demonstrates the feasibility of utilizing Fe(III)-modified montmorillonite as remediation material for TCS, TCC and other related pharmaceutical and personal care products (PPCPs).

No description available.

No description available.

Removal of organic matter is increasingly important to drinking water utilities and consumers. Organic matter is a significant precursor in the formation of disinfection by-products (DBPs). The maximum contaminant levels for (DBPs) are decreasing and more DBPs are believed carcinogenic. Traditional coagulation focuses on the removal of particulate matter and in the last decade soluble species have also been targeted with high coagulant doses. However, colloidal matter is smaller than particulate matter and therefore not easily removed by conventional drinking water treatment. This research focused on the conversion of soluble organic matter to colloids using relatively low doses of ferric sulfate coagulant and the subsequent removal of the colloids by filtration during drinking water treatment. The goal is to achieve enhanced removal of soluble organic matter with minimal chemical costs and residual formation. This study investigated the effects of pH, iron coagulant dose, turbidity, organic matter concentration, and temperature on colloid formation. Characterization of the colloidal organic matter was attempted using zeta potential and sizing analyses. Cationic low molecular weight, nonionic high molecular weight, and cationic medium molecular weight polymers were evaluated on their removal of colloidal organic matter. Colloidal organic matter formation was affected by changes in coagulation pH, coagulant dose, and organic matter concentration, whereas turbidity and temperature did not significantly impact colloid formation. Decreased coagulation pH caused increased organic carbon removal. As coagulant dose was increased, colloid formation initially increased to maximum and subsequently rapidly decreased. Colloid formation was increased as the organic matter concentration increased. Due to low sample signal, the colloids could not be characterized using zeta potential and sizing analyses. In addition, polymers were ineffective for aggregating colloidal organic matter when used as flocculant aids. / Master of Science

A presente pesquisa teve como objetivo a otimização de processos de precipitação química na remoção de fósforo de esgotos sanitários mediante a utilização de sais de ferro como coagulante. Analisou-se a remoção de matéria orgânica e produção de lodo obtidas. O trabalho foi desenvolvido com efluentes provenientes de duas estações de tratamento da SABESP, sendo elas a ETE Barueri lodos ativados convencional e ETE Ribeirão Pires tratamento anaeróbio com reatores UASB. Os ensaios de Jar-Test foram conduzidos em laboratório e o coagulante utilizado foi o cloreto férrico. Os resultados obtidos demonstram que a dosagem do coagulante, em ambos os efluentes estudados, resulta na remoção de fósforo total a valores inferiores a 1 mg/L. As dosagens de coagulante necessárias foram de 80 mg/L para a ETE Barueri e 60 mg/L para a ETE Ribeirão Pires. A remoção de carga orgânica também foi alcançada e valores de DBO5,20 inferiores a 10 mg/L são obtidos com dosagens inferiores às necessárias para a remoção de fósforo. A dosagem de coagulante necessária para a remoção de DBO5,20 a valores inferiores a 10 mg/L foi de 40 mg/L. A produção de lodo é o principal problema encontrado quando se utiliza precipitação química, a quantidade de lodo produzida é significativa e deve ser levada em consideração no dimensionamento do sistema de tratamento e disposição final. Incrementos na produção de lodo da ordem de 113% foram obtidos para a ETE Barueri e 51% para a ETE Ribeirão Pires quando foram consideradas as dosagens de coagulante necessárias a remoção de fósforo totais a valores inferiores a 1 mg/L. / The aim of the present study was the chemical precipitation optimization of phosphorus from domestic wastewater with a ferric salt as coagulant. The organic matter removal and the sludge production obtained were analyzed. The study was developed with effluents from two wastewater plants from SABESP, such as ETE Barueri conventional activated sludge and ETE Ribeirão Pires anaerobic treatment with UASB reactors. Jar-Test tests were done in laboratory and the coagulant used was the ferric chloride. The results show that the coagulant dosage, in both effluents studied, results in a total phosphorus removal to values lower than 1 mg/L. The necessary coagulant dosages were 80 mg/L to ETE Barueri and 60 mg/L to ETE Ribeirão Pires. The organic matter removal also was obtained and values of BOD lower than 10 mg/L are obtained to lower dosages than the necessary dosage to phosphorus removal. The necessary coagulant dosage to BOD removal to values lower than 10 mg/L was 40 mg/L. The sludge production is the main problem when chemical precipitation is used, the amount of sludge produced is significant and must be taken into consideration in the system project of treatment and final disposal. Increases in the sludge production were around 113% to ETE Barueri and 51% to ETE Ribeirão Pires when the necessary coagulants dosages were considered to total phosphorus removal to values lower than 1 mg/L.