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.

No description available.

No description available.

No description available.

No description available.

No description available.

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

The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. The thermal hydrolysis process has been used in several treatment plants around the world, but none currently operate in the US. Thermal hydrolysis causes cell walls to rupture under the effect of high temperature and high pressure and results in highly solubilized product which is readily biodegradable. The performance of the process was evaluated for a treatment plant located in Dallas, TX. The performance assessment was based on various characteristics including pH, solids removal, COD removal and gas production. The study was conducted in two phases to investigate the effect of change in mesophilic temperature (37°C and 42°C) and the effect of solids retention time (SRT) (15 days and 20 days). Thermally hydrolyzed combined (1:1) primary and waste activated sludge was fed to a Thermal Hydrolysis (TH) anaerobic digester and its performance was compared to a conventional mesophilic anaerobic digester receiving non pre-treated sludge. The thermal hydrolysis pre-treatment was found to be more effective as compared to the conventional anaerobic digester. The efficiency of the process varied slightly with increase in temperature but the change in SRT was seen to have a greater impact on the digester's performance. The pre-treatment technique was observed to deliver the best results at a 20 day SRT. / Master of Science

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

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.