Fate of Estrogenic Activity and Specific Endocrine Disrupting Contaminants (4-Nonylphenol and Polybrominated Diphenyl Ethers) During Wastewater Treatment and Effluent Polishing Operations
AdvisorArnold, Robert G.
Committee ChairArnold, Robert G.
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PublisherThe University of Arizona.
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AbstractDuring the past decade, estrogenic contaminants and polybrominated diphenyl ethers (PBDEs) received more and more attention due to their adverse effects as endocrine disruptors. There is a need to examine fate of these contaminants during wastewater treatment and effluent polishing process, as well as during the land application of biosolids as soil amendments, within the context of potable water reuse and sludge application, which have all been widely practiced.Two major research goals guided this research. The first goal was to develop experimental protocols measuring estrogenic activity (including nonylphenol) and PBDEs in environmental samples, especially in organic rich solid samples such as sludges, sediments and soils which are impacted by wastewater and/or application of biosolids. The second objective was to evaluate fate of estrogenic activity and PBDEs during conventional wastewater treatment, effluent polishing, and sludge handling processes including digestion, dewatering, composting, and land application of biosolids by using the protocols developed.The protocol developed to measure estrogenic activity or PBDEs in the solids includes extraction, cleanup, and determination steps. Each step is critical for the successful determination; however cleanup step was the most difficult. In this study, a C18 resin was used as the media to remove the bulk organic interferences in the measurement of estrogenic activity and nonylphenol. In comparison, Florisil was used in the cleanup step for PBDE analysis. In the development of each protocol, mobile phase was carefully selected and optimum cleanup strategy was determined, recovery of analytes during cleanup operation was measured. During the development of method measuring the estrogenic activity, effects of extraction variables such as solvent, pressure, and time were investigated. The performance of each protocol was examined by spike and recovery experiments.Experiments indicated that estrogenic activity and nonylphenol were largely removed during traditional wastewater treatment, soil aquifer treatment, and surface transport along a wastewater dependent stream. Examination of estrogenic activity and nonylphenol in sludge, sediments in contact with wastewater and mass balance analysis of these estrogenic contaminants in traditional wastewater treatment plants and infiltration basins indicated that both adsorption and biodegradation play important roles. In comparison, estrogenic activity and nonylphenol were persistent during anaerobic sludge digestion. More experiments are warranted to understand fate of PBDEs during sludge digestion process, although limited data show possible degradation.
Degree ProgramEnvironmental Engineering