Date of Award

Summer 2022

Project Type

Dissertation

Program or Major

Environmental engineering

Degree Name

Doctor of Philosophy

First Advisor

Paula Mouser

Second Advisor

James Malley

Third Advisor

Nancy Kinner

Abstract

Wastewater is a complex matrix containing a wide range of microorganisms and chemical compounds. For public health purposes, it is critical to monitor for harmful microorganisms and evaluate the toxicity of chemicals present in industrial and municipal wastewaters on human and ecosystem health. Over the past decade, sophisticated technologies such as high-throughput sequencing have enabled the development of molecular tools, which are now widely employed for tracking pathogens and assessing toxicity of municipal and industrial wastewaters. Molecular tools for biomonitoring of wastewater are designed to target specific microbial biomarkers including nucleic acids, proteins and antigens. Accordingly, this dissertation applied molecular tools to characterize water quality and assess the occurrence of pathogens for improved management of industrial and municipal wastewater.Chapter 2 quantifies toxicity of wastewater generated from hydraulically fractured natural gas wells. My research involved adapting two toxicity microassays, a broad spectrum BioLuminescence Inhibition Assay (BLIA) employing the halotolerant bacterium Aliivibrio fischeri, and a specific cytotoxicity N-acetylcysteine (NAC) thiol reactivity assay to quantify toxicity of flowback and produced water (FPW) after hydraulic fracturing. My results suggested that both acute toxicity and thiol reactivity diminished with time after fracturing and were influenced by specific chemical additives in the wastewater, as opposed to sample fraction (solids vs liquid), or shale formation. In Chapter 3, I assessed concentrations of SARS-CoV-2 genetic material (N1 and N2) in both liquid and solids wastewater samples from seven coastal New England treatment facilities. My work shows that municipal wastewater treatment facilities efficiently remove SARS-CoV-2 from effluent, with the greatest removal from the liquid phase after secondary clarification. Viral particles were found at lower levels in wastewater sampled post-secondary treatment and were below detection after disinfection, compared to the primary-treated wastewater. Sludge samples had the highest concentrations, suggesting affinity of the viral genetic material toward the solids. In Chapter 4, I compared temporal trends of SARS-CoV-2 RNA biomarker signals on a small university campus (UNH Durham) versus biomarker signals for the broader Durham community before, during, and post-vaccination. My results revealed that COVID-19 vaccine administration resulted in a significant decrease in SARS-CoV-2 biomarker concentrations in wastewater concurrent with decreasing number of COVID-19 infections in the community. When new variants emerged, a significant increase in SARS-CoV-2 biomarker concentration occurred in the wastewater parallel with increasing number of COVID-19 infections in the UNH community. Taken together, this dissertation demonstrates that molecular tools optimized for wastewater from both municipal and industrial sources can effectively be used for assessing temporal trends in toxicity and pathogen prevalence to provide early detection and mitigate human health risks.

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