Date of Award

2016-01-01

Degree Name

Doctor of Philosophy

Department

Civil Engineering

Advisor(s)

W. Sahne Walker

Second Advisor

Wen-Ye Lee

Abstract

The presence of compounds of emerging concern (CECs) such as endocrine disrupting compounds (EDCs) and herbicides in municipal wastewater present environmental challenges because conventional treatment systems were not designed to remove such compounds. The removal of Bisphenol-A (BPA), 17?-Estradiol (E2), 17β-Ethinylestradiol (EE2), nonylphenols (NP), and select herbicides and pesticides were investigated in two municipal wastewater treatment plants (WWTP) in El Paso, TX. In addition, the environmental impact of the two municipal wastewater treatment plants was investigated, including the theoretical addition of UV/H2O2. The use of UV/H 2O2 was studied in a UV bench scale pilot unit, and its performance was compared to the use of peracetic acid (PAA) in the same system. The analysis of EDCs in the WWTPs revealed average removals of 93% and 94% for WWTP-A, and 87% and 99.6% for WWTP-B were observed for BPA and NP, respectively. Estrogen species were detected in less than 5% of the samples; herbicides and pesticides were below detection limits for all of the collected samples. EDC removal agreed with reductions in estrogenic activity observed by yeast bioassay. The environmental assessment of the WWTPs including the implementation of an advanced oxidation process (AOP) with the use of 10 mg/L H2O 2 yield increments of 3% global warming potential, 2% acidification potential, 5% eutrophication potential, 3% freshwater aquatic ecotoxicity potential, and 42% in terrestrial ecotoxicity potential. A holistic Eco-Score Card was created for evaluating AOP implantation, and the addition of 10 mg/L of peroxide was observed to result in a 13% increase of the overall environmental impact, as compared with the current WWTP. In the bench scale AOP experiments, direct UV (1 J/cm3, 254 nm) irradiation was found to remove up to 19%, 11% and 61% of the initial concentrations of estradiol, BPA and NP respectively. The UV irradiation of solutions with 10 mg/L initial concentration of H2O2 yield removals of 99.4%, 94% and 84% for estradiol, BPA and NP respectively. The UV irradiation with 5 mg/L PAA showed removals of >99.9%, >99.9% and 24% for estradiol, BPA and NP, respectively.

Language

en

Provenance

Received from ProQuest

File Size

78 pages

File Format

application/pdf

Rights Holder

Juan C. Bezares-Cruz

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