The distribution system is the primary cause of taste and odor complaints in drinking water. This research examined the ability of small diameter pipes used in home plumbing to affect drinking water quality. The properties of the materials were investigated in the absence of disinfectant and the presence of either chlorine or chloramines. A panel was trained in flavor profile analysis (FPA) according to Standard Methods 2170B and used to assess the sensory properties of all samples. Chemical analyses were performed to determine disinfectants, total organic carbon (TOC), pH and specific organic contaminants. The first part of this study investigated PEX pipes manufactured by the silane (PEX-b) and peroxide (PEX-a) cross-linking technology, using the utility quick test (UQT) method. Silane PEX-b had a greater effect on water quality properties such as odor, TOC and residual disinfectant demand than peroxide-linked PEX-a. Chemical analysis revealed that PEX pipes can contribute fuel oxygenates such as ETBE (PEX-b) and possibly MTBE (PEX-a) to drinking water. PEX pipes did not contribute any significant trihalomethanes to drinking water. This study showed that the type of PEX used in homes will determine the extent to which drinking water quality is affected. The second part of this study used simulated plumbing rigs to investigate seven different materials under low flow and stagnant conditions; chlorinated polyvinyl chloride, cross-linked polyethylene, polyethylene, epoxy-lined copper, copper, stainless steel, galvanized iron and glass (control). Results showed that these plumbing materials have the potential to affect water quality characteristics such as TOC concentrations, residual disinfectant and odor when newly installed in homes. A high TOC concentration was consistent with the presence of a distinct odor or a high FPA intensity rating. Galvanized iron produced the worst odors that were consistently described as "motor oil". Polyethylene generated more intense plumbing associated odors than PEX or cPVC plastic material. cPVC and copper generated the least odors. Both copper pipe and epoxy-lined copper consumed residual chlorine and chloramines. / Master of Science

Taste-and-odor (T&O) compounds are frequently produced by cyanobacterial blooms in bodies of water. Geosmin, perhaps the most common T&O compound produced by these blooms, is not effectively removed by conventional water treatment processes and frequently causes the tap water to have an off flavor. Although geosmin is not harmful when ingested, it damages the consumers' confidence in the cleanliness of their water. There are treatment options for geosmin removal, but the most common methods are often not implemented until complaints are made by consumers.There has been an increasing amount of research on the use of polymerase chain reaction (PCR)-based methods that can detect the presence of the geosmin synthase gene which is responsible for the production of geosmin. If the geosmin synthase gene is found to be present in an emerging cyanobacterial bloom, water treatment facilities can prepare in advance to treat for geosmin. In this study, we developed a qPCR (quantitative polymerase chain reaction) assay that can detect the presence of the geosmin synthase gene in several species of cyanobacteria within the Anabaena genus. We tested our assay, as well as PCR assays designed by Giglio et al. (2008) and Suurnäkki et al. (2015) on extracted Anabaena flos-aquae DNA, biosynthesized Anabaena ucrainica DNA and DNA extracted from environmental samples of Deer Creek Reservoir, Strawberry Reservoir, and Utah Lake. It is important to note that the geosmin gene was not confirmed to be present in any of the environmental samples nor in the Anabaena flos-aquae DNA and our assay did not test positive on these samples. Our qPCR assay was very successful when used with the biosynthesized Anabaena ucrainica DNA. We used the results to estimate a DNA standard curve that can be used to estimate the starting concentration of the geosmin synthase gene. Because our assay was not successfully used with any extracted DNA, further testing and calibration may be necessary to produce a DNA standard curve that is representative of DNA that is extracted. Further calibration of the DNA standard curve was not done because there were no geosmin events during the course of the research.Development of PCR-based methods of detecting geosmin-producing cyanobacteria requires genetic sequencing information of the target-organisms. Thus, further development of PCR-based methods requires that the local geosmin-producers be identified and sequenced. Our assay as well as the assay designed by Moore (2019) can assist with the identification of these species by classifying their genus.

Indiana University-Purdue University Indianapolis (IUPUI) / Taste-and-Odor (T&O) occurrences are a worldwide problem and can locally have extensive socio-economic impacts in contaminated waterbodies. Tracing odorous compounds in surface waters or controlling the growth of producing organisms is particularly challenging. These approaches require the understanding of complex interactions between broad climate heterogeneity, large-scale physical processes such basin hydrology, lake/reservoir circulation, responses of aquatic ecosystems and communities. Eagle Creek Reservoir (ECR), a eutrophic water body, located in central Indiana experiences annual odorous outbreaks of variable durations and intensities that can impair its water quality. Two major compounds, 2-methylisoborneol and geosmin, have been identified as the main culprits occurring seasonally when the reservoir receives high discharges and nutrient loads from its main tributaries. Under these conditions, the growth of T&O-producing bacteria tends to take over other phytoplanktic organisms. Discrete samples collected within the water column during severe outbreaks in 2013 revealed that some bacterioplankton members belonging to Actinobacteria (Streptomyces) and Cyanobacteria (Planktothrix) were involved in the generation of T&O compounds. Most of this production occurred in the upper layers of the water column where higher abundances of key enzymes from MIB and geosmin metabolic pathways were detected. Application of a copper-based algaecide to curb the biosynthesis of bacterial metabolites led to geosmin production (linked to Cyanobacteria) being quickly terminated, whereas MIB levels (linked to Actinobacteria) lingered for several weeks after the algaecide treatment. Significant chemical differences in the association of these metabolites were measured in ECR. Geosmin was dominantly found cell-bound and settling after cellular death increases susceptibility to biodegradation in bottom sediments. MIB was mostly found dissolved making it less susceptible to biodegradation in bottom sediments. Genetic data identified Novosphingobium hassiacum and Sphingomonas oligophenolica (α- Proteobacteria) as potential degraders of geosmin and, four Flavobacterium species (Bacteroidetes) as potential MIB degraders. The role of Eagle Creek natural sediments in the removal of bacterial metabolites via chemical adsorption was also tested but was not proven efficient. Bacterial breakdown activity was demonstrated to be the major loss mechanism of MIB and geosmin.

Thirteen volunteer panelists were trained according to <i>Standard Method</i> 2170, flavor profile analysis (FPA). Following training these panelists underwent triangle test screening to determine whether or not they could detect the odorants used in this study. Following triangle testing, panelists underwent directional difference testing to determine if temperature affected odor perception when presented with two water samples. Following directional difference testing, panelists used FPA and evaluated water samples that contained odorants at either 25°C or 45°C. Samples containing geosmin cooled to 5°C were also evaluated. Sensory analyses experiments indicate that odor intensity is a function of both aqueous concentration and water temperature for geosmin, MIB, nonadienal, n-hexanal, free chlorine, and 1-butanol. The higher water temperature resulted in an increase in odor intensity for some, but not all, concentrations of geosmin, 2-methylisoborneol, <i>trans-2,</i> <i>cis-6-</i>nonadienal, n-hexanal, free chlorine, and 1-butanol. Additionally, above 400 ng/L of geosmin, 400 ng/L of MIB, and 100 ng/L the odor intensity was equal to or less than the odor intensity at 600, 600, and 200 ng/L, respectively. Henry's Law should predict that an increase in concentration would increase the amount of odorant the panelist comes into contact with; however, results demonstrated that at specific aqueous odorant concentrations odor perception did not follow Henry's Law. Odor response to drinking water containing isobutanal was affected by concentration but not water temperature. / Master of Science

River ecosystems across the US and globally face numerous stressors that impact both ecological function and water quality. In 2015-16, municipalities along the Dan River in southern Virginia experienced repeated taste and odor (TandO) issues in their drinking water that originated from the river source water. Given that the source of TandO issues during these events were unknown, this research aimed to identify patterns in the distributions of river microorganisms that could help identify potential biological causes. Monthly water, sediment, and periphyton samples were collected for a full year from the Smith and Dan Rivers to quantify actinomycete, fungi, and chlorophyll a concentrations, which have historically been linked to TandO problems, and to characterize changes in microbial community structure. Although no significant TandO event occurred during the study period, the work produced unique and valuable data that describe patterns of microbial populations and communities in a river ecosystem. Results from the study show the abundances of actinomycetes, fungi, and chlorophyll a expressing seasonal and regional variation by habitat. From a broader ecological perspective, microbial communities sampled from water, sediment, and periphyton were each unique from each other regardless of river reach and season sampled. Overall, this research adds to our understanding of river ecology by detailing the microbial abundance and diversity in three river habitats, including periphyton, that can be used to predict sources of river TandO in future events, and offers new questions regarding how microbial diversity changes over space and time. / Master of Science / In 2015-16, cities along the Dan River in Virginia experienced multiple taste and odor (T&O) events that led to earthy and musty odors in drinking water. As part of a larger project looking at a range of possible chemical and biological sources of T&O, this research aimed to identify changes in abundance of river microorganisms that might indicate potential biological causes to T&O events. Monthly samples of water, sediment, and algal growth were collected for a year from 12 sites on the Smith and Dan Rivers. Samples were analyzed for abundances of three known T&O causing groups of organisms—actinomycetes, fungi, and photoautotrophs—and to characterize changes in total microbial communities as an indicator of ecological change occurring along the rivers. Although a significant T&O event did not occur during the study period, the research produced valuable descriptions of how important microorganisms change in a freshwater ecosystem. Actinomycetes elevated in the lower Dan River during fall, fungi elevated during the spring, and chlorophyll a was highest in the upper Smith River during winter, suggesting that photoautotrophic growth was more likely to be linked to previous T&O events. The diversity and makeup of the microbial communities in the rivers was primarily dependent on where they were growing (water, sediment, or periphyton) and secondarily on the season or the river reach. Combined, these results will help to identify causes of future T&O events in the Dan River and also provide new insights into ecological patterns of microorganisms in river ecosystems.

The use of polymer pipes is now very common in home plumbing and other parts of the drinking water distribution system. Many taste and odor complaints in drinking water are known to originate from contact of water with materials. The ability of polymer pipes used in home plumbing to affect drinking water quality and aesthetics was investigated using the Utility Quick Test (UQT). Analysis of water quality and aesthetics were conducted in the absence of disinfectant and the presence of either chlorine or chloramines. A Flavor Profile Analysis (FPA) panel was trained according to Standard Methods 2170B to evaluate the organoleptic characteristics of the samples. Laboratory analyses were performed to determine levels of total organic carbon (TOC), disinfectant residual, pH and to attempt to identify specific volatile organics. The first part of this study investigated HDPE, cPVC and epoxy lined copper pipes using the UQT method. Both HDPE and epoxy-lined copper had significant effects on water quality and aesthetics during the approximately 10 day exposure of the UQT. HDPE and epoxy-lined copper leached significant amounts of TOC and consumed more disinfectant than controls, but in different amounts. cPVC was the most inert of the materials tested and had the least impact on water quality and did not contribute any significant odor. None of the pipes tested appeared to contribute trihalomethanes to drinking water, but further analysis revealed that the compounds may actually be generated and subsequently sorbed into pipe walls. These data show the effects of newly installed polymeric pipe materials and their potential to impact water quality in differing capacities. The second part of this study compared the results of the UQT on HDPE, epoxy lined copper, cPVC, PEX-a and PEX-b with the goal of comparing and contrasting how five different polymeric plumbing materials can impact drinking water quality. Results demonstrated the short-term ability of all pipe materials except cPVC to impact water quality and aesthetics. This data could potentially be useful in generating selection criteria for homeowners and plumbing professionals regarding the impact of newly installed plumbing materials. / Master of Science

Most taste-and-odor problems in the United States are caused by algal blooms in rivers and reservoirs. In the past, most of the attention has been focused on the formation of geosmin and MIB by blue-green algae (cyanobacteria), which cause earthy and musty odors, respectively. Little work has been performed, however, on equally obnoxious odors caused by other golden-brown and yellow-brown algae which are responsible for fishy, grassy, floral, and melon odors. Additionally, the production of odorous compounds can occur upon oxidation of a nonodorous parent compound. The objective of this research was to determine the effect of three oxidants - chlorine, potassium permanganate, and chlorine dioxide - on solutions of pure odorous as well as nonodorous compounds and algal extracts containing a mixture of odor-related compounds. Oxidant dosages used were in the ranges expected during water treatment. Rashash (1994) identified several odor-causing compounds in pure cultures of golden-brown, yellow-brown, green, and blue-green algae. The compounds selected for oxidation during this study were isolated by Rashash (1994) and are as follows: isovaleric acid (rancid, dirty socks), β-cyclocitral (tobacco, grape), phenethyl alcohol (roses), myristic acid (odorless), palmitic acid (odorless), linoleic acid (odorless), and linolenic acid (watermelon). All seven compounds were oxidized and evaluated by a trained flavor panel for sensory analysis. Because the three oxidants used in this study produced substantial changes in the odors of linoleic acid and linolenic acid, test solutions buffered to a pH of 7 of linoleic acid and linolenic acid were further evaluated by Flavor Profile Analysis (FPA) for sensory determination and gas chromatography/mass spectroscopy (GC/MS) for quantitative measurement of odorous compounds. Volatile compounds produced by Synura petersenii (fishy/cucumber) were also analyzed and evaluated. When linoleic acid (odorless) was treated with potassium permanganate (0.25 mg/L, 1.0 mg/L, and 1.5 mg/L) and chlorine dioxide (1.0 mg/L and 2.0 mg/L), a grassy odor was produced at an FPA intensity of 2-4 (weak). The compound causing this odor was confidently identified from GC/MS analysis as n-hexanal. The compound 2,4-decadienal, which exhibits a frying odor, was also identified in oxidized samples and could contribute to off-odors. Chlorine dioxide and potassium permanganate at the same doses were also effective in eliminating watermelon odors in linolenic samples. Flavor Profile Analysis of samples treated with chlorine was inconclusive since chlorine and acetone, which was used as an organic solvent, produce an alcohol odor at an FPA intensity of approximately 2 (weak) which masked other odors present. Flavor Profile Analysis of oxidized Synura extracts indicated that the fishy odor was destroyed and cucumber or grassy odors were unmasked. Potassium permanganate at a concentration of 0.25 mg/L was effective in eliminating all odors in Synura culture samples. Chlorine and chlorine dioxide at concentrations of 2.0 mg/L and 3.0 mg/L, respectively, eliminated the fishy odor in Synura samples. In both cases, however, vegetation or grassy odors were detected at an FPA intensity of less than 2 (very weak). / Master of Science

Chlorine (Cl₂(sq»' chlorine dioxide (ClO₂ ) and potassium permanganate (KMnO₄) were evaluated as oxidants for the removal of grassy and cucumber odors associated with the pure compounds, cis-3-hexenol and trans-2, cis-6-nonadienal, respectively, and for the removal of fishy odors associated with a culture of an alga, Synura petersenii. The effects of the oxidants on the pure compounds were assessed both by Flavor Profile Analysis (FPA) and gas chromatography/mass spectrometry (GC/MS). The effects of the oxidants on the algae culture were evaluated by FPA only. In addition, an unoxidized sample of Synura petersenii was analyzed by gas chromatography coupled with mass spectrometry (GC/MS) for possible identification of fishy-smelling compounds. Chlorine (1-6 mg/L) and KMn04 (0.25-4 mg/L) markedly reduced grassy and cucumber odors associated with the two compounds. Gas chromatography/mass spectrometry confirmed that these compounds were reduced to below method detection limits. Levels of Cl₂(&q) required (up to 6 mg/L) to reduce the grassy odors associated with cis-3-hexenol were higher than those of KMnO₄ â ¢ The high Cl₂(&q) doses may have contributed to the formation of chemical odors observed by panelists. Two isomers of chlorohexenol were confidently identified as byproducts of cis-3-hexenol chlorination and may have contributed to the chemical odors that developed after CI2(aq) treatment. Chlorine and KMnO₄ (both at 10 mg/L) either reduced or destroyed the fishy odor associated with the culture of Synura petersenii; however, oxidation caused either the development or unmasking of fruity, cucumber, melon and grassy odors. Chlorine dioxide (3 mg/L) did not reduce the grassy and cucumber odors associated with cis-3-hexenol and trans-2, cis-6-nonadienal , respectively. Gas chromatography and mass spectrometry confirmed that concentrations of these compounds were not reduced to below method detection limits. Furthermore, at a concentration of 10 mg/L, Cl₂ did not effectively reduce either the fishy or other objectionable odors associated with Synura petersenii culture. Hexanal, with an odor described as "green" or "like lettuce heart," and trans-2, cis-6-nonadienal (cucumber odor) were confirmed as algal products in a two-week-old culture of Synura petersenii. In addition, decatrienal was confidently identified as a product of Synura and may have contributed to the fishy odor associated with this alga. / Master of Science

Although utilities attempt to avoid offensive smelling compounds in consumer's drinking water, their efforts are often hampered by a lack of data or knowledge of the physical, chemical, and sensory properties of odorants. Many factors affect the ability of a consumer to detect odors, including: concentration, presence of chlorine/other odorants, temperature, and the individual's sensitivity. This research developed a simplified static-headspace technique to determine Henry's Law constants at multiple temperatures and then use these data to calculate the enthalpy of solution so that new Henry's Law constants can be calculated at any temperature using the van't Hoff Equation. The method was applied to three taste-and-odor compounds of moderate water solubility (about 100 mg/L). 2-Methylisoborneol (2-MIB) is a methylated monoterpene alcohol that is produced by actinomycetes and blue-green algae and has a musty odor that is detectable at 4-10 ng/L water. Geosmin, also produced by actinomycetes and blue-green algae, has a detectable earthy odor at 5-10 ng/L. trans-2, cis-6-Nonadienal is enzymatically synthesized from poly-unsaturated fatty acids by diatoms like Synura and has cucumber and fishy odors detectable at 10-40 ng/L levels. The new static headspace method uses standard glassware used in odor-analyses. 500 mL wide-mouth Erlenmeyer flasks were modified with septum sampling ports to measure vapor phase concentrations by SPME/GC-MS. Unitless Henry's Law constants were determined at multiple temperatures using the vapor and aqueous phase concentrations. From the Henry's Law constants, the enthalpies of reactions were calculated. For these compounds, the values for Henry's Law constants ranged from 0.002 to 0.02 for four temperatures between 20 to 45 °C with geosmin and 2-MIB having similar and higher values than for nonadienal. The constants increased with increasing temperature. The enthalpies of vaporization from the aqueous phase were determined to be in the range of 50-80 kJoule/mole. The experiments were repeated with fulvic acid added to the aqueous media at different concentrations. The Henry's Law constants were decreased with the presence of fulvic acid; however no correlation between the concentration of fulvic acid and the decrease was observed. The decrease in constants for 2-MIB and geosmin were very small compared to nonadienal. Finally the measured Henry's Law constants were used to predict gas phase concentrations of odorants for known aqueous concentrations of geosmin, 2-MIB, and nonadienal. The results were correlated to the human sensory data obtained from flavor profile analysis. The data demonstrated that as the gas phase concentration increased, the perceived odor intensity also increased, but only up to a certain point. The vapor phase concentration increased linearly as the aqueous phase concentration increased, but the FPA intensity increased at a lower rate and leveled-off. The increase in the FPA rating at 25ï °C was greater than at 45 °C although the vapor phase concentration was greater at 45 °C. For samples containing 400 and 600 ng/L geosmin, 400 and 600 ng/L, 2-MIB, 100 and 200 ng/L nonadienal, the increase in gas phase concentration did not increase the FPA ratings of the panelists. It was concluded that, utilities will be challenged to assess and treat high concentrations of geosmin, 2-MIB, and nonadienal. Sensory analysis will not be predictive of aqueous or vapor concentration at high levels and may be misleading if used to determine a treatment strategy. Chemical analyses, especially solid phase microextraction technique is very effective in measuring these compounds even at low ng/L levels. The temperature-related Henry's Law constants can be used to assess remediation systems, human exposure and sensory perception by predicting gas phase concentration in a variety of situations, such as showering and washing dishes. / Master of Science

As the bottled water trend continues to rise across the nation, drinking water utilities have become more concerned with ensuring consumer satisfaction of their product. Although public water supplies are safeguarded by regulations, aesthetically unappealing taste-and-odor problems have led consumers to search for alternative water sources, such as bottled water or tap water processed by point-of-use filters. Consequently, taste-and-odor monitoring has become important to the drinking water industry. Because many utilities use chlorine to disinfect the water, chlorine odor often masks other more subtle odors that may eventually cause consumer complaints. As treated water travels from the water treatment plant to the consumer, chlorine residual diminishes and may reveal a water's naturally less-pleasing odors. Consequently, odor monitoring at the water treatment plant, where chlorine concentrations are at a peak, may not identify potential displeasing smells. Proper evaluation of these odor-causing substances requires that the chlorine odor first be eliminated before evaluating any remaining odors. Dechlorinating agents can remove chlorine, but some will produce other unwanted odors or even remove certain odorous compounds. This research describes the efficiency of several of these agents (ascorbic acid, hydrogen peroxide, oxalic acid, sodium nitrite, and sodium thiosulfate) in dechlorinating chlorinated solutions of the earthy-smelling compound geosmin and musty-smelling MIB. Interfering odors in reusable containers pose another problem in drinking water odor analysis. The most common odor-analysis methods (TON and FPA) involve the use of glass flasks, which often either develop chalky odors or have persistent lingering odors from previous evaluations. Furthermore the glass flasks break easily and are difficult to clean. This research also evaluates the suitability of four types of disposable plastic containers for odor analyses. / Master of Science