In order to maintain high quality safe drinking water, we need to understand what happens after the water has been cleaned at the drinking water plant and before it gets to the consumer’s house. Even if low concentrations of toxic contaminants enter the drinking water distribution system (DWDS) there is potential for contaminants to accumulate and be released by changes in flow or water conditions in high concentrations at the tap. For this study, we collected solid material from Park City, Utah that accumulated within the DWDS, along with a year of monthly monitoring of the DWDS. These solids were tested under five chemical and physical changes to see what contaminants can be released into the drinking water, with focus on eight elements: antimony (Sb), arsenic (As), chromium (Cr), copper (Cu), lead (PBS), and thallium (Tl) termed inorganic contaminants (TICs), also pipe elements iron (Fe) and manganese (Mn). From this study it was found that high concentrations of Sb, As, and Tl could be released under some conditions. Fortunately, we saw that the release of Cr, Cu, and Pb was either unmeasurable or so low that the amount never approached drinking water standards. The factors that were the most influential in producing high concentrations were both high and low pH, high temperature, low Cl2, and CaSO4. The most surprising observation was the very high concentrations of Tl released, reaching up to 90 μg/L, where the safe limit in drinking water is 2 μg/L. This study showed the importance of monitoring changes within the DWDS and that small changes can cause harmful levels of some contaminants to be released into the drinking water. However, monthly monitoring showed under normal conditions no harmful levels were detected.

The presence of pollutants known as emerging contaminants in water and wastewater is a topic of growing interest. Emerging contaminants, which include endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs), are compounds that remain relatively unknown, although their adverse effects have been proven. Emerging contaminants are not satisfactorily removed by traditional treatment methods; therefore, there is a need for innovative techniques. Advanced oxidation processes (AOPs) have been recognized as successful removal methods for these problematic pollutants. However, technical success is not the only factor that must be considered. Process engineering, environmental, and economic and social parameters were considered. A holistic analysis was completed using a ranking system to determine the performance of several AOPs (ozonation, UV, photocatalysis, the Fenton reaction, and integrated processes). Ultimately, H2O2/O3 presented the highest average ranking (3.45), with the other processes showing similar performance, with the exception of TiO2 photocatalysis (2.11).

Environmental contamination has become a significant threat to the health and well-being of mankind as well as to the environment, prompting the establishment and implementation of stringent environmental regulations. The ability to accurately detect and quantify contaminants, such as mercury (Hg), uranium (U), and volatile organic compounds (VOCs), in real-time, in situ is of significant importance to monitoring and remediation efforts. In an effort to develop a real-time, fast-response detector that is portable, highly sensitive, and cost efficient, this research explored the feasibility of utilizing cavity ringdown spectroscopy (CRDS) in conjunction with various plasma sources and vacuum cavities to accurately detect trace quantities of contaminants. The feasibility of detecting Hg with a low power, low temperature candle-shaped microwave-induced plasma (MIP) and a copper surfatron microwave cavity with various plasma discharge tube configurations in conjunction with cavity ringdown spectroscopy (MIP-CRDS) is discussed. Detection limits were on the order of 221 ppt Hg in the vapor phase for the candle-shaped MIP and improved by a factor of 10 with the tube-shaped plasma. The ability to detect elemental Hg naturally-evaporating from contaminated soils and solutions was evaluated, and 10’s of ppt were consistently obtained. Additionally, the fine structure of the Hg 253.65 nm transition was observed with each iteration of this approach. The potential of effectively generating uranium atoms and ions with a low-power, lowlow rate microwave-induced plasma was evaluated. Uranium emission spectra covering 320 – 430 nm were obtained, labeled, and compared to the available literature values. Calibration curves were generated, and the detection limits were determined to be ~0.4 ppm. The feasibility of measuring U incorporating diode laser-plasma-CRDS was explored. The preliminary studies clearly show the ability to detect U vapor with this technique and sub-ppm detection limits were obtained. A continuous wave cavity ringdown spectroscopy system (CW-CRDS) incorporating commercially available telecommunications diode lasers was constructed, and the overall sensitivity of this system was evaluated by utilizing the absorption of the asymmetric C-H stretch overtones of several VOCs, including benzene, chlorobenzene, 1,2-dichlorobenzene, toluene, and acetone. Detection limits are determined to be in the ppb’s for each of the organics examined.

Many types of contaminants of emerging concern (CECs), including per- and poly-fluoroalkyl substances (PFAS), have been found in leachate of operating municipal landfills. However, information on CECs in leachate of historic landfills (≥3 decades since closure, often lacking engineered liners or leachate collection systems) and the related risk posed from groundwater plumes discharging to nearby aquatic ecosystems is limited. In this study, 48 samples of leachate-impacted groundwater were collected from 20 historic landfills in Ontario, Canada. The CECs measured included artificial sweeteners (ASs), PFAS, organophosphate esters (OPE), pharmaceuticals, bisphenols, sulfamic acid, perchlorate, and substituted phenols. Several landfills, including ones closed in the 1960s, had total PFAS concentrations similar to those previously measured at modern landfills, with a maximum observed here of 12.7 μg/L. Notably elevated concentrations of several OPE, cotinine, and bisphenols A and S were found at many 30-60 year-old landfills. There was little indication of declining concentrations with landfill age, suggesting historic landfills can be long-term sources of CECs to groundwater. A full-year field study was performed on a 0.5-km reach of an urban stream receiving contaminated groundwater from nearby historic landfills. Elevated concentrations of ammonium, the AS saccharin, an indicator of old landfill leachate, and CECs (e.g., maximum total PFAS of 31 μg/L) in the shallow discharging groundwater were relatively stable across the seasons but were spatially restricted by hyporheic exchange and discharge of other groundwater. This indicates a patchy but long-term exposure for endobenthic organisms, which are rarely monitored. Stream water concentrations were more dilute, but increased markedly across the landfill stretch, and showed signs of increases in winter and after rain/snowmelt events. These findings provide guidance on which CECs may require monitoring at historic landfill sites and suggest how landfill monitoring programs could be improved to fully capture the risk to receiving water bodies. / Thesis / Master of Science (MSc) / Historic landfills are a known source of groundwater contamination. This study investigated whether these landfills contain new groups of chemicals, called contaminants of emerging concern (CECs), which are suspected to pose serious environmental and human health risks. This study found many CECs at high concentrations in most of the 20 historic landfill sites investigated, even those closed up to 60 years. A full-year investigation at one historic landfill site showed that organisms living in the sediments of a nearby stream are exposed to high concentrations all year long. Concentrations in the stream increased as it flowed past the landfill, and may be higher in winter and after rains, times monitoring is rarely done. The elevated concentrations of harmful contaminants in this water are potentially threatening the stream ecosystem. Operators of historic sites should consider testing for CECs and ensure that monitoring strategies accurately evaluate the risk posed to the environment.

Increasing population across the globe paved the way for rapid growth in industrialization. Pharmaceuticals, automotive, textiles, agriculture, electronics, electrical and many other industries discharge different types of heavy metals, dyes and organic contaminants into ground water. These discharges are released into lakes and rivers without prior treatment causing huge environmental impact to the environment. Among different remediation techniques, adsorption was considered the most promising method because of its low-cost and high efficiency. Biomass is considered as the most practical and renewable source for production of bio products and biofuels. Biomass is also used for carbon sequestration and as an essential element to produce hydrochar and biochar which are considered as the 21st century black gold. Hydrochar and biochar can be used as an excellent low-cost adsorbent for the removal of heavy metals, dyes and organic contaminants from water. This dissertation work focuses on, firstly, development of novel oxone treated hydrochar as an adsorbent for the efficient removal of Pb(II) and Methylene Blue (MB) from aqueous solutions. Secondly, preparing novel ozone oxidized hydrochar treated with polyethyleneimine for removal of Remzol Brilliant Blue (RBB) and Remzol Reactive Black (RRB) dyes from aqueous solutions. Thirdly, producing high-performance CO2 activated biochar as an adsorbent for efficient removal of Aniline from aqueous solution. All prepared hydrochar and biochar adsorbents were characterized by SEM, TGA, FTIR, Elemental analysis, conductometric titration, and N2 adsorption-desorption isothermal analyses (BET and BJH). The adsorption capacities were determined by Atomic absorption spectrometry (AAS) and Ultraviolet–visible spectroscopy (UV-VIS) respectively. The adsorption capacity of each prepared biochar or hydrochar was determined and both kinetic and isothermal studies were performed. The optimal preparation conditions and adsorption parameters were determined for each adsorbent.

Continuous population growth and rapid industrial advancement and development have paved the way for ever increasing environmental pollution. At present, water pollution is a serious global issue that threatens environmental sustainability. The contamination of aquatic bodies with potentially toxic organic and inorganic substances are the result of world-wide anthropogenic activities. These pollutants can have detrimental health consequences on humans and ecosystems. Over the past decades, techniques such as chemical precipitation, ion-exchange, adsorption, membrane filtration, and electrocoagulation-flocculation have been developed and employed for the treatment of drinking and wastewater. Among the currently available techniques, pollutant removal by adsorption is most promising due to its cost-effectiveness, simplicity in operation, environmental friendliness, and abundance of adsorbents. This study emphasized the utilization of biochar (BC), after appropriate surface modification, for the removal of potentially toxic contaminants. In the first study, a base activated biochar was synthesized by treating the biochar with potassium hydroxide (KOH) at 700 ℃ in a muffle furnace for 1 h. The resulting high surface area biochar (KOHBC) was used for the removal of Cr(VI), Pb(II) and Cd(II). In the second study, a biochar-supported polyaniline hybrid was synthesized for aqueous chromium and nitrate adsorption. Introduction of amine and imine groups to the biochar facilitated the removal of these contaminants. In the final study, a composite containing Fe-Ti oxide/biochar (Fe2TiO5/BC) was synthesized for sorptive removal of metal cations, oxy anions, inorganics, and organic contaminants from aqueous solutions. Additionally, this composite was used as a photocatalyst towards aqueous methylene blue (MB) degradation. The surface chemistry and composition of these adsorbents were examined by PZC SEM, TEM, XPS, FTIR, TGA, elemental analysis, and surface area measurements.

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There are many reports indicating the presence of emerging contaminants such as: estrogen hormones, 1,4-dioxane and perfluoro-octanoic acids in the natural environment. Estrogen hormones are considered important emerging class of contaminants due to their endocrine disrupting effects. These compounds are invariably found in the environment originating mostly from natural sources. Trace concentrations of estrogen hormones (low µg/L concentrations) have been detected in municipal wastewater treatment plants and observed in receiving water bodies. 1,4-Dioxane (C4H8O2) is used as an organic solvent and solvent stabilizer numerous in chemical processes. The United States Environmental Protection Agency (US-EPA) has recognized 1,4-dioxane as a toxic chemical and a possible human carcinogen. 1,4-dioxane has been detected as a contaminant in the natural environment, drinking water supplies, superfund sites, public groundwater sources in the United States, Canada and Japan at concentrations greater than the permissible standards. Perfluorinated chemicals such as perfluoro-octanoic acid (PFOA) and perfluorooctane-sulfonate (PFOS) have been manufactured for use in a variety of industrial and consumer applications. Due to their environmental persistence, PFOAs have been detected in surface waters at a number of locations at concentrations ranging from pg/L to ng/L. Elevated concentrations of PFOAs have been measured in surface and ground waters near specific point sources. Through this project, successful attempts have been made for the destruction of emerging contaminants using ultrasound. This study deals with the optimization of various process parameters for the destruction of estrogen hormones. The influence of process parameters such as power density, reactor geometry, power intensity, ultrasound amplitude, and external mixing was investigated. Artificial neural network (ANN) approach was used to describe the interactions between optimized parameters. The important findings obtained in the present work for the optimized estrogen degradation can help tackle the challenges of scale up such as operational optimization and energy consumption. The effect of process conditions such as pH and presence of oxidizing agents on the ultrasonic destruction of 1,4-dioxane and PFOA was studied. Acidic conditions favored the destruction of both the compounds. The presence of activated sulfate radicals enhanced the reaction rate kinetics. An innovative technology using electric potential and ultrasound for the removal organic contaminants was developed. The existence of organic contaminants in ionic form under certain process conditions has led to the development of this technology. Applying a low electric potential across the probe enhances the mass transfer of the contaminants into effective reaction zone, thereby enhancing the total destruction. A two-fold increase in the reaction rates was observed. This study shows ultrasound as an efficient and effective treatment technology for the destruction of emerging contaminants. / Civil Engineering