The ubiquity of pharmaceuticals and personal care products in water systems is well known. With the increasing implementation of water reuse schemes in the US, concern about potential health effects of these compounds in humans has risen. While potential synergistic effects of chronic low doses exposure to a cocktail of these compounds is still being studied, it is prudent to monitor and attenuate these trace organic compounds (TOrCs) from our water sources. This research initially focused on identifying suitable `indicator' TOrCs based on theoretical physico-chemical parameters and actual experimental data. It was concluded that an indicator list will be specific to the goal targeted with dependence on treatment process, occurrence and analytical ease. Quantification of these TOrCs are part per trillion levels in water requires accurate, precise and robust analytical techniques. The next part of this research was spent on developing three different analytical methods with LC-MS/MS for the sensitive detection of TOrCs in several different water matrices including raw sewage and final drinking water. The treatment efficacy of granular activated carbon for attenuation of TOrCs is studied in detail with emphasis on developing correlations between TOrC removal and bulk organic parameters of water like UV absorbance and fluorescence by using rapid small-scale column testing. The results indicate a correlation between removal of TOrCs and bulk organic parameters that is independent of water quality. The effectiveness of commercially available activated carbon based point-of-use (POU) devices for removal of a set of TOrCs from water was evaluated. The data indicated that POUs are a viable option for treatment of TOrCs but specific removal depends on type of device, water quality and amount of water treated. Finally, further research was targeted at identifying transformation products as a result of oxidation of polyfluorinated precursor materials in reclaimed waters. The results illustrated that toxic perfluorocarboxylic acids can be formed on oxidation of fluorotelomer unsaturated carboxylic acids that are known to be present in water.

Wastewater reuse is fast becoming an imperative issue based on the developments in water/wastewater engineering coupled with increasing pressures on water resources. Trace organic compounds (TOrCs) that exist in water/wastewater, are a serious threat once they were released in the environment. During the past decade, there has been much progress toward understanding the occurrence, fate and toxicology of trace organic pollutants that enter the environment in treated wastewater. The objective of the first part of this research was to evaluate the combined effects of sequential anaerobic/aerobic digestion on residual TOrCs, concentrating on chemicals that are responsible for observed estrogenic/androgenic activities in biosolids. Full-scale digestion was simulated using bench-scale bioreactors in which the primary independent variables were retention time, temperature, and oxygen loading during aerobic digestion. Treatment-dependent changes in estrogenic/androgenic activity and concentrations of specific Endocrine disrupting compounds (EDCs) were measured. Results suggest that standard mesophilic anaerobic digestion increases the total estrogenic/androgenic activity of sludge while aerobic digestion was effective in the reduction of estrogenic/androgenic activity as a supplementary treatment stage. The second part of the study was focused on the fate of TOrCs and estrogenic activity in water and sediment of the Santa Cruz River, which is effluent dependent except during infrequent periods of rainfall/runoff in Tucson area. Several sampling campaigns were carried out from 2011 to 2013. Results suggest that some organic TOrCs, including those that contribute to estrogenic activity, were rapidly attenuated with distance and time of travel in the Santa Cruz River. Indirect photolysis of estrogenic compounds through the river might play an important role for the observation of estrogenic activity changes in the SCR. Hydrophobic TOrCs may accumulate in river sediments during dry weather periods. Riverbed sediment quality is periodically improved through storm-related scouring during periods of heavy rainfall and runoff. Wastewater effluent can be applied to the algal biodiesel industry based on regional water stress across the world. In the third part of the research, reclaimed wastewater was explored for this purpose, simultaneously satisfying the needs for water, macronutrients such as nitrogen and phosphorus, and micronutrients necessary for growth of microalgae. At the same time, algal growth in conventionally treated wastewater will improve water quality through the same nutrient removal processes and perhaps by lowering residual levels of trace organics that are an impediment to potable reuse. Results showed that metals levels in most municipal wastewaters are unlikely to disrupt growth, at least by metals tolerant microalgae like Nannochloropsis salina. Cells can grow without inhibition on nutrients from treated municipal wastewater or a centrate stream derived from wastewater treatment. The results also suggest while wastewater provides a suitable nutrient source for algal growth, there is simply not enough municipal wastewater available to support a meaningful biofuels industry without water recycling and nutrient recovery/reuse from spent algae. The last part of the dissertation was the application of water/wastewater treatment techniques, specifically advanced oxidation processes (AOPs) in other industrial sectors. In the integrated circuit production industry, chemical formulations used for megasonic cleaning typically contain hydroxides, peroxides and carbonates, which can affect particle removal efficiency and feature damage. The role of carbonates and ammonia in modulating the oxidation power of megasonic irradiated alkaline solutions through the scavenging of hydroxyl radicals by varying levels of carbonates, bicarbonates, ammonia and solution temperatures on net generation of hydroxyl radicals for applications in semiconductor industry was investigated in this study. The simulation of actual megasonic cleaning process was carried out at acoustic frequency of ~ 1 MHz and different power densities. Carbonate ions were better scavengers of hydroxyl radicals than bicarbonate ions. The effect of bulk solution temperature revealed that the rate of generation of hydroxyl radicals at a power density of 8 W/cm² increased with temperature from 10-30°C, which suggests an increase of transient cavitation with temperature.

Due to their potential health impact on human beings and ecosystems, persistent trace organic compounds (TOrCs) have aroused concern from both the public and professionals. In particular, the discharge of pharmaceuticals, endocrine disrupters, disinfection byproducts and other TOrCs from wastewater treatment plants into the environment is an area of extensive current research. This work studies the fate and treatments of TOrCs, with emphases on advanced oxidation processes (AOPs). This work presents predicted removal efficiencies of a variety of engineered and natural processes for 55 frequently encountered TOrCs in treated wastewater, based on previously reported data and using existing predictive models. Correlations between physicochemical and biological properties of TOrCs and treatment performance were explored. Removal of TOrCs in all processes investigated in this study was found to be sensitive to matrix effects. Heuristic guidelines for selection of sequenced treatment processes for TOrCs management were established. A field reconnaissance of natural process of TOrCs was conducted by analyzing the occurrence and fate of a suite of TOrCs, as well as estrogenic activity in water and sediments in the Santa Cruz River, an effluent-dependent stream in Tucson, Arizona. Some TOrCs, including contributors to estrogenic activity, were rapidly attenuated with distance of travel in the river. TOrCs that have low biodegradability and low octanolwater partitioning coefficients were less removed. Results of independent experiments indicated potential indirect photodegradation of estrogenic compound by reactive species generated from photolysis of effluent organic matter. Utilizing advanced oxidation processes (AOPs) as tertiary water and wastewater treatment is an option to prevent discharge of TOrCs into the environment. Compared to conventional AOPs, the ability of generating hydroxyl radicals (•OH) without additional doses of hydrogen peroxide (H2O2) or ozone makes ultraviolet (UV) photolysis of ferric hydroxo complexes a novel AOP, especially in acidic environments. A Fe(III)/UV254 kinetic model, which combines Fenton-like mechanism, and photolyses of Fe3+, FeOH2+ and H2O2 was proposed and experimentally validated to predict Fenton-like and H2O2 direct UV254 photolysis scenarios, individually. Nevertheless, the model underestimated the ferrous ion development during Fe(III)/UV254 photolysis, perhaps due to the overprediction of the oxidation of Fe2+ by •OH. The UV/H2O2 AOP was also studied in this work. A predictive kinetic model was developed to evaluate process efficiency of oxidation of p-cresol by UV/H2O2 photolysis based on a complete reaction mechanism, including reactions of intermediates with •OH. Results of this study highlight the significance of consideration of radical scavenging effects by the byproducts from oxidation of organic matter in model prediction performance.

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A large variety of Advanced Oxidation Processes (AOPs) to degrade trace organic compounds during water treatment have been studied on a lab scale in the past. This paper presents the combination of inline electrolytic chlorine generation (ECl2) with low pressure UV reactors (UV/ECl2) in order to allow the operation of a chlorine-based AOP without the need for any chlorine dosing. Lab studies showed that from a Free Available Chlorine (FAC) concentration range between 1 and 18 mg/L produced by ECl2 up to 84% can be photolyzed to form, among others, hydroxyl radicals (OH) with an UV energy input of 0.48 kWh/m3. This ratio could be increased to 97% by doubling the UV energy input to 0.96 kWh/m3 and was constant throughout the tested FAC range. Also the achieved radical yield of 64% did not change along the given FAC concentration range and no dependence between pH 6 and pH 8 could be found, largely simplifying the operation of a pilot scale system in drinking water treatment. Whereas with ECl2 alone only 5% of benzotriazoles could be degraded, the combination with UV improved the degradation to 89%. Similar results were achieved for 4-methylbenzotriazole, 5-methylbenzotriazole and iomeprol. Oxipurinol and gabapentin were readily degraded by ECl2 alone. The trihalomethanes values were maintained below the Germany drinking water standard of 50 µg/L, provided residual chlorine concentrations are kept within the permissible limits. The here presented treatment approach is promising for decentralized treatment application but requires further optimization in order to reduce its energy requirements.:Introduction Methodology Results and Discussion Conclusions Author Contributions Funding Conflicts of Interest Appendix A References