Date of Award

Spring 2021

Document Type

Open Access Thesis

Department

Chemistry and Biochemistry

First Advisor

Susan D. Richardson

Abstract

Certain industrial processes, such as energy extraction and utilization, generate massive amounts of wastewater with various geogenic and synthetic contaminants. Oil and gas wastewaters are characterized by elevated halide levels, particularly geogenic bromide and iodide. Concentrations in produced wastewaters have been reported as high as thousands of mg/L of bromide and tens of mg/L of iodide. Large volumes of these wastewaters are stored, transported, and disposed of, potentially impacting drinking water sources. Because conventional wastewater treatment fails to remove halides, oil and gas wastewater disposal, even after treatment, facilitates the formation of brominated and iodinated disinfection by-products (DBPs) at downstream drinking water treatment plants. These compounds are of interest because of their notably higher toxicity relative to their chlorinated counterparts. This study reports a comprehensive analysis of 69 regulated and priority unregulated DBPs in disinfected surface waters impacted by oil and gas wastewater. Impacted samples had a 43% and 55% increase in total DBPs formed after chlorination and chloramination. Chlorinated waters gave the highest levels of overall DBP formation, including concentrations of regulated DBPs that would exceed regulatory limits of 80 μg/L and 60 μg/L for trihalomethanes and haloacetic acids, respectively. Chloraminated samples had more iodinated DBP formation and the highest levels of haloacetamides (23 μg/L) in impacted water. Calculated toxicities were higher for both impacted waters treated with chlorine and chloramine than corresponding treated raw water samples. Chloraminated impacted waters had the highest calculated cytotoxicity, likely due to higher levels of the more toxic iodinated DBPs and haloacetamides. These findings demonstrate that oil and gas wastewater discharged to surface waters can adversely impact downstream drinking water supplies and potentially affect public health.

Rights

© 2021, Dallas Graham Abraham

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