Aboard the International Space Station, potable water will likely be produced from recycled wastewater. The National Aeronautic and Space Administration (NASA) plans to use iodine as a disinfectant, and, consequently, the formation of iodinated disinfection by-products (IDBPs) requires investigation. Objectives of this research were to determine possible precursors of IDBPs, identify IDBPs formed, and apply flavor profile analysis (FPA) as a tool to evaluate water qaulity. Experiments were performed by separately reacting iodine with each of the following organic compounds: methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, acetone, and formaldehyde. NASA previously identified all of these compounds in wastewater sources under consideration for recycling into potable water. Experiments were performed at pH 5.5 and 8, iodine concentrations of 10 and 50 mg/L, and organic concentrations of 5 and 50 mg/L. Gas chromatography/mass spectrometry was used to identify and monitor the concentrations of organic species. Spectrophotometry was used to monitor the iodine concentration. Acetone was the only compound identified as an IDBP precursor and it reacted to produce iodoacetone and iodoform. Concentrations of iodoform from 0.34 mg/L to 8.637 mg/L were produced at conditions that included each pH level, iodine concentration, and acetone concentration. The greatest iodoform concentration was produced at pH 8 from 50 mg/L of iodine and acetone. FPA indicated that the odor threshold concentration (OTC) of iodoform was 1.5 ug/L, and the OTC of iodine was 500 ug/L. Both iodine and iodoform have medicinal odors, making it difficult to distinguish each compound when present in a mixture. / Master of Science

This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur iv during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.

ABSTRACT As far back as the early 1900?s when it was discovered that water could be a mode of transmitting diseases, chlorine was used to disinfect water. In the 1970?s, the formation of disinfection by-products (DBPs) from the reaction of chlorine with natural organic matter was discovered. Since then there have been various studies on alternative disinfectants that could inactivate microorganisms and at the same time form less or no disinfection by-products. More recently the ultraviolet (UV) irradiation has been used to both disinfect and remove organic contaminants in drinking water. Though the use of UV irradiation has been found to be very effective in the inactivation of microorganisms, it does not provide a residual effect to maintain the water?s microbial quality in the distribution system. Due to this, a secondary disinfectant such as chlorine has to be used to achieve microbial stability, suggesting that the formation of chlorination disinfection by-products would still occur but perhaps in different quantities and with different chemical species. In this research, the use of factorial experiments and single factor experiments were used to determine the effects of pH, alkalinity and UV-fluence (dose) on the formation of three classes of disinfection by-products; haloacetic acids (HAAs), haloacetonitriles (HANs) and trihalomethanes (THMs). These disinfection by-products were measured in water samples following post-UV chlorination and the UV treatment was either UV photolysis or UV/H₂O₂. From the factorial experiment results, treatment of synthetic water with UV/H₂O₂, an advanced oxidation process (AOP), produced fewer post-UV chlorination disinfection by-products (PCDBPs) than UV photolysis. For chlorinated PCDBPs, the percentage difference between UV photolysis and UV/H₂O₂ was 55, 65 and 38% for total HAAs (HAA₉), total HANs (THANs) and total THMs (TTHMs) respectively. The percentage difference between UV photolysis and UV/H₂O₂ for brominated PCDBPs was 41 and 42% for HAA9 and TTHMs respectively. Both the use of pH and alkalinity proved to be factors that were significant in affecting the yields of the PCDBPs studied. Increases in alkalinity were found to increase the formation of PCDBPs in the treatment of synthetic water with UV/H₂O₂. Alkalinity had the opposite effect for PCDBP formed under UV photolysis conditions. Increases in pH always decreased the formation of PCDBPs. In the single factor experiments, haloacetic acid concentrations were unaffected as alkalinity was increased but dichloroacetonitrile and chloroform increased in concentration under treatment conditions of UV photolysis followed by chlorination. The UV/H₂O₂ treatment resulted in a decrease in concentration of the PCDBPs. In the pH studies, water samples were subjected only to the UV/H₂O₂ treatments and a reduction in concentration of PCDBPs occurred between pH 7 and 9.

ABSTRACT As far back as the early 1900?s when it was discovered that water could be a mode of transmitting diseases, chlorine was used to disinfect water. In the 1970?s, the formation of disinfection by-products (DBPs) from the reaction of chlorine with natural organic matter was discovered. Since then there have been various studies on alternative disinfectants that could inactivate microorganisms and at the same time form less or no disinfection by-products. More recently the ultraviolet (UV) irradiation has been used to both disinfect and remove organic contaminants in drinking water. Though the use of UV irradiation has been found to be very effective in the inactivation of microorganisms, it does not provide a residual effect to maintain the water?s microbial quality in the distribution system. Due to this, a secondary disinfectant such as chlorine has to be used to achieve microbial stability, suggesting that the formation of chlorination disinfection by-products would still occur but perhaps in different quantities and with different chemical species. In this research, the use of factorial experiments and single factor experiments were used to determine the effects of pH, alkalinity and UV-fluence (dose) on the formation of three classes of disinfection by-products; haloacetic acids (HAAs), haloacetonitriles (HANs) and trihalomethanes (THMs). These disinfection by-products were measured in water samples following post-UV chlorination and the UV treatment was either UV photolysis or UV/H₂O₂. From the factorial experiment results, treatment of synthetic water with UV/H₂O₂, an advanced oxidation process (AOP), produced fewer post-UV chlorination disinfection by-products (PCDBPs) than UV photolysis. For chlorinated PCDBPs, the percentage difference between UV photolysis and UV/H₂O₂ was 55, 65 and 38% for total HAAs (HAA₉), total HANs (THANs) and total THMs (TTHMs) respectively. The percentage difference between UV photolysis and UV/H₂O₂ for brominated PCDBPs was 41 and 42% for HAA9 and TTHMs respectively. Both the use of pH and alkalinity proved to be factors that were significant in affecting the yields of the PCDBPs studied. Increases in alkalinity were found to increase the formation of PCDBPs in the treatment of synthetic water with UV/H₂O₂. Alkalinity had the opposite effect for PCDBP formed under UV photolysis conditions. Increases in pH always decreased the formation of PCDBPs. In the single factor experiments, haloacetic acid concentrations were unaffected as alkalinity was increased but dichloroacetonitrile and chloroform increased in concentration under treatment conditions of UV photolysis followed by chlorination. The UV/H₂O₂ treatment resulted in a decrease in concentration of the PCDBPs. In the pH studies, water samples were subjected only to the UV/H₂O₂ treatments and a reduction in concentration of PCDBPs occurred between pH 7 and 9.

abstract: N-nitrosodimethylamine (NDMA) is a probable human carcinogen and drinking water disinfection by-product. NDMA forms as the product of reactions between chloramines and precursor compounds in water. This dissertation aims to provide insight into the removal of NDMA precursors, their nature, and a method to aid in their identification. Watershed-derived precursors accounted for more of and greater variability to NDMA formation upon chloramination than polymer-derived precursors in environmental samples. Coagulation polymers are quaternary amines, which have low NDMA yield but high use rates. Watershed-derived precursors were removed up to 90% by sorption to activated carbon, but activated carbon exhibited much less (<10%) sorption of polymer-derived precursors. Combined with literature NDMA molar yields of model anthropogenic compounds, where anthropogenic chemicals in some cases have NDMA yields >90% and biological compounds always have yields <2%, trace, organic, amine containing, anthropogenic chemicals were implicated as the most likely source of NDMA precursors in the watershed. Although activated carbon removes these precursors well, identification of individual compounds may result in more cost effective mitigation strategies. Therefore, I developed a method to isolate NDMA precursors from other organic matter into methanol to facilitate their identification. Optimization of the method resulted in a median recovery of NDMA precursors of 82% from 10 surface waters and one wastewater. The method produces 1,000X concentrated NDMA precursors and, in collaboration with the University of Colorado Center for Environmental Mass Spectrometry, time of flight mass spectrometry (TOF-MS) was performed on multiple treated wastewater and raw drinking water isolates. During TOF-MS, tertiary amines can cleave to form a neutral loss and an R group ion that is dependent on the original structure and I wrote a software program to “trawl” exported TOF-MS spectra for the diagnostic neutral loss resulting from fragmentation of tertiary amines. Methadone was identified as one new NDMA precursor that occurs at concentrations that form physiologically relevant levels of NDMA in surface water and wastewater. The approach used here to identify NDMA precursors is adaptable to other unknown disinfection by-product precursors given that a functional group is known that can 1)control sorption and 2)produce a predictable diagnostic fragment. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015

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