During the early 1980s, concern over the poor quality of the nation's drinking water began to arise. Though the Safe Drinking Water Act (SDWA) had been passed almost a decade earlier, many problems still existed. These problems included the inability of the Environmental Protection Agency to promulgate new drinking water standards and to enforce new and existing standards. To address the shortcomings of the original act, Congress passed the 1986 SDWA Amendments. This document attempts to accomplish two main goals. The first is to summarize selectively the requirements of the 1986 Safe Drinking Water Act (SDWA) Amendments as reflected in proposed and finalized drinking water regulations. The areas of coverage include proposed regulations for eight inorganic and thirty synthetic organic chemical contaminants, the Surface Water Treatment Rule (SWTR), and the Total Coliform Rule (TCR). In order to facilitate an understanding of the SDWA and the 1986 Amendments, a sectional analysis was provided in an appendix. The second goal of this document is to assess the economic impact of this legislation upon Virginia water facilities. In this regard, the cost of water treatment technologies whose use will likely increase as a result of the legislation have been estimated, compiled, and documented. These technologies include granular activated carbon (GAC); reverse osmosis; ion exchange; and various aeration, filtration, and disinfection technologies. Several case studies that assess and highlight the direct impacts of the 1986 SDWA Amendments upon Virginia water facilities are presented. / Master of Science

The concentrations of chlorine dioxide (CI02), chlorine, chlorite (CIO2), and chlorate (CI03) were evaluated following pretreatment of raw water by CI02 at water treatment plants in New Castle, Pennsylvania; Charleston, West Virginia; Skagit, Washington; and Columbus, Georgia. Chlorite and chlorate concentrations were unaffected by any of the water treatment processes and did not vary as a function of time of travel in the distribution system. Chlorine dioxide, which was analyzed on-site at two water treatment plants, reformed in the clear well and in the distribution system following post chlorination. The chlorite-removal capability of powdered activated carbon (PAC) was evaluated in both laboratory- and pilot-scale studies. Chlorite removal by PAC in laboratory studies decreased with increasing pH over a range from pH 5.5 to 7.5 and varied with the type of PAC. Chlorite was reduced to chloride at pHs ranging from 5.5 to 7.5, but CI03- formed at the pH 5.5 through 6.0. The pilot plant study; which was conducted at Newport News, Virginia; evaluated CI02 removal by PAC enmeshed in a floc blanket in a pulsed-bed, solids-contact clarifier. An average of 27 percent of the CI02 was removed when the PAC dose was 10 mg/L PAC and 57 percent when it was 20 mg/L PAC. Chlorate was not removed by PAC, but the concentrations could be reduced if the CIOz generator was properly operated. / Master of Science

Private wells are understudied potential sources of opportunistic pathogen (OP) infections. OPs, including Legionella and Mycobacterium, are of particular concern for immunocompromised individuals and are known to proliferate in drinking water systems. Much of our knowledge surrounding OP occurrence and growth in drinking water relates to municipal drinking water systems, which primarily use surface water sources and are always treated with primary and secondary disinfection in United States. However, OP occurrence and growth in private wells is not well understood and it is unclear how the knowledge developed in municipal systems will translate to private well systems with rare and infrequent exposure to chemical disinfectants. In addition, because private wells are more susceptible to microbial contamination than municipal systems, the impact of flooding on OP occurrence is of particular concern. Two private well field surveys were conducted to document the incidence of OPs in private well systems. One survey conducted in North Carolina private wells with no history of recent flooding was focused on molecular and culture-based detection of Legionella spp. and Legionella pneumophila. The other survey was a broader molecular (i.e., DNA-based) characterization of the incidence of Legionella spp., L. pneumophila, Mycobacterium spp., Mycobacterium avium (the most commonly nontuberculous mycobacteria associated with disease), and Naegleria fowleri in private wells with recent history of flooding (i.e., Hurricanes Harvey and Irma in 2017, or the Great Louisiana Floods in 2016, extending to Texas, Florida, and Louisiana). All samples in both studies were analyzed for total bacterial 16S rRNA genes, indicator bacteria (e.g., total coliform and Escherichia coli) and inorganic constituents. Information about well system characteristics were obtained through questionnaires sent to participating residents. Widespread detection of OP DNA markers were noted in the flooded well survey. Legionella spp. (detectable in 50-100% of well waters, depending on the flood event) and Mycobacterium spp. (detectable in 13.2-45.0% of well waters) were the most commonly detected among the OPs targets. At the genus level, L. pneumophila (7.9-65.5%) and M. avium (7.9-32.5%) were less commonly detected, but still highly variable. It is not possible to judge whether these OP levels were elevated as a result of the flooding because the sampling was carried out as an emergency response and background levels were not previously tested. Also of interest was whether well characteristics could predict OP levels, including well depth, well type, or treatment. However, none of these emerged as significant predictors of OP detection frequency or levels. Similarly, these OP DNA markers were not elevated in homes reporting submerged wellheads or system damage, suggesting that detection of these OPs is more dependent on the groundwater that supplies these private wells than influx of contaminated surface water. The incidence of DNA markers pertaining to N. fowleri, the "brain eating amoeba" that causes rare incidences of primary amebic meningoencephalitis (PAM), tended to be lower (5.0-12.7%) than that of other OPs targeted, but was more frequently detected in wells reporting submerged well heads, suggesting its occurrence was related to contamination from flood water. A positive association between total bacteria and occurrence of both Legionella spp. and Mycobacterium spp., was observed in private wells of all surveyed areas, contrary to observations in municipal drinking water systems with secondary disinfectant residuals. On the other hand, Legionella reportedly has an optimal growth range of 20-42 °C in municipal systems and recent surveys of municipal systems reported a strong association between Legionella spp. and temperature that was not observed for private wells in this study. We speculate that the essentially "infinite" water age and lack of disinfectant for well water, may contribute to these differences relative to municipal water supplies. The results presented in this work are likely an overestimation of OPs numbers in private wells, as molecular detection of OPs does not distinguish between live and dead cells. In addition, sample sizes were limited by laboratory throughput and budget. Identifying key variables impacting the occurrence of OPs in private wells, given that our study shows that these pathogens are relatively common, might someday help limit the risk of infections. / Master of Science / Non-fecal pathogens that are capable of growth in drinking water systems and causing illness primarily in individuals with compromised immune systems are referred to as opportunistic pathogens (OPs). OPs of concern in drinking water systems in the United States include members of the Legionella genus (i.e., Legionella spp.) and Mycobacterium genus (i.e., Mycobacterium spp.), as well as Naegleria fowleri (also known as “the brain-eating amoeba”). Much of our knowledge surrounding OP occurrence and growth in drinking water relates to municipal drinking water systems. Under the right conditions, OPs have the ability to grow in municipal drinking water systems and in building plumbing systems despite the use of disinfectants. However, OP occurrence and growth in private wells is not well understood and it is unclear how the knowledge developed in municipal systems translates to private well systems that rarely utilize chemical disinfectants. In addition, because private wells are more susceptible to microbial contamination than municipal systems, the impact of flooding on OP occurrence is of particular concern. Two private well surveys were conducted to document the incidence of OP DNA markers and culturable OPs in private well systems. The first survey was conducted in North Carolina private wells with no history of recent flooding and focused on quantification of DNA markers for Legionella spp. and L. pneumophila, as well as culturable L. pneumophila. The second survey was conducted in flood-impacted private wells in vi Texas, Florida, and Louisiana following Hurricanes Harvey and Irma in 2017 and the Louisiana Floods of 2016, quantifying five DNA markers for OPs (Legionella spp., L. pneumophila, Mycobacterium spp., M. avium, and N. fowleri). All water samples in both studies were also analyzed for total bacterial numbers (i.e., total number of copies of a gene present in all bacteria), certain bacteria that indicate environmental and fecal contamination (e.g. total coliform bacteria and Escherichia coli), and inorganics. Information about well system characteristics was obtained through questionnaires sent to participating residents. While it was not possible to sample before the flooding events and determine the background detection rates, this survey found that detection of the target OPs in the flood-impacted wells was widespread, but highly variable. Both culture-based and DNAbased testing methods were used to verify the results because each approach has strengths and weaknesses. Detection of DNA markers indicates the genetic material of the organism being tested for is present and detects DNA of organisms that are both dead and alive. Thus, DNA detection may overestimate the presence live (and infectious) pathogens. Detection of culturable pathogens indicates the organism is alive, but only detects pathogens that readily grow on culture media. There may be other pathogens in the water that do not readily grow on the media. Thus culture may underestimate the occurrence of pathogens. DNA markers for Legionella spp. (detectable in 50-100% of well waters) and Mycobacterium spp. (detectable in 13.2-45.0% of well waters) were the most commonly vii detected among the targets in this study. The detection of DNA markers for L. pneumophila (7.9-65.5%) and M. avium (7.9-32.5%) was less common. There were no private well characteristics, such as well depth, well type, or treatment that emerged as significant predictors of these OP detection or levels. Similarly, these OPs were not elevated in recently flooded homes reporting submerged wellheads or system damage. Thus, detection of these OPs was found to be widespread and sporadic. Detection rates of N. fowleri, which causes rare incidences of primary amebic meningoencephalitis (PAM), DNA was lower (5.0-12.7%) than other OPs, and was also not related to private well characteristics. However, N. fowleri DNA was more frequently detected in wells with wellheads that were submerged due to flooding than in wells with unsubmerged wellheads, as were total coliform bacteria (an indicator of environmental contamination) and total bacterial numbers. This demonstrates concern that submergence of wellheads during flooding is a concern for the introduction of microbial contamination in private wells. This work also explored two trends characteristic of municipal systems that were not observed in these surveys of private wells. First, positive associations between overall bacterial numbers and DNA markers for both Legionella spp. and Mycobacterium spp. were observed in private wells in all surveyed areas. This is contrary to what has been reported for overall bacterial numbers in municipal drinking water systems with a secondary disinfectant residual. Second, Legionella has been known to have an optimal growth range of 32 to 42 °C (90 to 108 °F) in municipal systems and recent surveys of municipal systems with both a free chlorine and chloramine secondary disinfectants viii showed a strong association between Legionella spp. and temperature. These associations were not observed in private wells in this work. Continuous disinfection treatment in municipal drinking water systems may eliminate certain microbes, lowering overall levels of bacteria, while OPs may persist by resisting disinfection, resulting in no correlation between total bacteria and OPs. Private wells do not generally use continuous disinfection and represent low-nutrient environments where naturally occurring OPs can grow alongside other bacteria. The results of this study are likely an overestimation of OPs infection risk associated with private wells, as infection can only be caused by live OPs, which cannot be directly determined by measuring DNA markers. In addition, sample sizes were limited by laboratory throughput and budget. Identifying key variables that impact the occurrence of OPs in private wells is necessary to minimize the risk of associated infections linked to private wells. This work provides strong preliminary evidence that OP occurrence in private wells is relatively commonplace. Science-based options for at-risk (e.g., immunocompromised) individuals to decrease their exposure to OPs in private well water need to be developed.

A <i>Pseudomonas</i> sp. capable of degrading tertiary butyl alcohol (TBA) as a sole carbon source, was isolated from a groundwater aquifer (50 ft. deep) at a petroleum refinery. The most probable number (MPN) of TBA degrading microorganisms was 4.9 x 10³ organisms/g (dry wt) of subsurface soil. Pristine subsurface soils, which did not have a history of petroleum contamination, had MPNs of < 2 TBA degrading organisms/g (dry wt) indicating a natural enrichment process at the refinery site. The Q_O2 of <i>Pseudomonas</i> sp. was 4.2 ml O₂/mg dry wt/h when TBA was the substrate. The optimum pH for growth was 7.0. The organism grew faster in continuous culture when TBA was the sole carbon source with a doubling time 33.6 h. The doubling time in batch culture was 112.3 h. When yeast extract was added to a mineral salts + TBA medium to concentrations greater than 1 mg/ml, TBA degradation was inhibited. When the yeast extract concentration was 0.1 mg/ml, a diauxy effect was seen in the growth rate. This suggested that TBA degradation by <i>Pseudomonas</i> sp. was subject to a regulatory mechanism. / M.S.

Chlorine dioxide has been used in drinking water treatment for the reduction of trihalomethanes and tastes-and-odors. Recently, chlorine dioxide was implicated as the source of offensive "cat-urine-like" and "kerosene-like" odors in drinking water. The purpose of this project was to determine the cause of odors observed in customers homes at times when chlorine dioxide was being applied to drinking water. Data were obtained through a survey and field sampling at utilities experiencing odor events. Once the cause was determined, potential water-treatment procedures were evaluated in laboratory-scale studies. Results from a survey sent to water utilities throughout the United States showed that customers who recently had installed new carpeting complained of odors more than those who had not. The use of chlorine dioxide caused responses to intensity of certain tastes-and-odors to increase, two of these odors were cat urine and kerosene. Field sampling at two water companies during odor events resulted in the discovery of low-levels of residual chlorine dioxide (0.2-0.7 mg/L) at the tap's of customers. Both the cat-urine- and kerosene-like odors were detected by the research team. To verify a proposed mechanism of odor generation, chlorine dioxide was volatilized in a room with new carpeting. Both odors were produced in amounts great enough to be easily detected by the entire panel. The removal of residual chlorite from drinking water would block a mechanism by which chlorine dioxide may be reformed from reactions between residual chlorite and free chlorine added for distribution system residual maintenance. Chlorite was removed by powdered activated carbon (PAC) enmeshed in alum floc in laboratory-constituted water and Po River water. A high level of PAC (50 mg/L) was required to effect good removal. A simulated floc-blanket clarifier effectively removed high levels of chlorite (>5 mg/L) from drinking water for long periods (12 hours) when PAC in high concentration was enmeshed in the floc. Chlorine dioxide reformed in the distribution system of two water companies. When customers opened water faucets, chlorine dioxide volatilized into the room and reacted with organic compounds present in the household air (e.g. from new carpeting) producing the offensive cat-urine-like and kerosene-like odors. The reformation of chlorine dioxide could be effectively eliminated if residual chlorite could be removed by contact with high levels of PAC enmeshed in an alum floc such as one could produce in a floc-blanket clarifier. / Master of Science

Robust decision support tools that aid water utilities to make informed, swift and precise decisions are becoming the need of the hour. Application of sophisticated models to aid the process of condition assessment and risk analysis on water pipelines have been limited owing to the lack of scalability, inability to incorporate external open source datasets and mathematically complicated output results. Interactive visualization of resultant model output is the key element in extracting valuable information to support decision making. This thesis presents a framework for visualization of data related to drinking water pipelines. Critical components of strategic, tactical and operational level decision making are explored in context with data presentation and information depiction. This thesis depicts various aspects of developing GIS web applications and their important functionalities for query and visualization of data. Multiple facets of data storage, standardization and application development are highlighted in this document. Publishing of application geo processing services in web environment is done through Virginia Tech enterprise geodatabase. Risk assessment and Performance models developed by a utility are projected in the application environment through help of widgets. Applications are coded into links on a Drupal website (www.pipeid.org) for model dissemination and utility engagement purposes. / Master of Science / Drinking water supply network primarily consists of pipelines, pumping stations, reservoir basins and treatment plants. Water pipelines are routinely inspected to check their condition and maintain appropriate water quality. Management of these subsurface assets should be given prime importance for maintaining high standards of services at acceptable cost to customers. An integral step in accomplishing this task is to view pipeline network in a geographic map. Different factors affecting pipeline condition are displayed on the map in the form of individual layers. Such real-world problems are analyzed with the help of Geographical Information System (GIS) tools that incorporate spatial features with tabular information. Moreover, interpretation of raw data into meaningful insights and distribution of allocated knowledge to all the concerned parties can be efficiently accomplished using rich internet applications. This thesis presents a framework to use GIS tools for developing web applications using raw data samples from contacted water utilities. Sample web applications are created and discussed in the form of case studies. Also, the challenges in water utility sector with respect to utilizing GIS tools for supporting daily decision-making processes is highlighted in this document. The recommendation to improve the suggested framework and adding more functionalities to developed applications are presented at the end with references.

This document details the results of a study that employed a single element, spiral-wound, thinfilm composite nanofiltration (NF) membrane pilot to assess the treatment effectiveness for aerated and unaerated groundwater supplies. Phase 1 consisted of using raw, unaerated groundwater with standard cartridge filtration (CF) and scale inhibitor (SI) as pretreatment to NF. During the first phase, four water recoveries and crossflow velocities were evaluated to observe how operational conditions affected permeate water quality. Phase 2 involved the simulation of a 70-foot transmission pipeline and sand filter (SF) pilot in series with CF and SI addition pretreatment, prior to NF. Phase 3 employed tray aeration prior to the SF pilot. The pilot was operated for 1,483 run-hours over the three phases, whereupon operational and water quality monitoring ensued to assess NF efficiency. Biological activity tests and foulant analyses were performed to further characterize source water. It was determined statistically that changes in operational conditions in Phase 1 such as crossflow velocity did not significantly affect constituent mass transfer. Phase 2 demonstrated that NF removed total dissolved solids and total organic carbon content greater than 96 percent (%) and 86%, respectively. Phase 3, which exhibited operational difficulties and flux decline, suggested that additional pretreatment is required for NF operation using aerated groundwater. Dimensional analysis (DA) and diffusionbased mass transfer models were employed to predict permeate chloride content for each testing phase; it was determined that the DA overpredicted chloride concentrations by 10 magnitudes and diffusion models were predictive when compared to actual values. The transient response to feed water perturbations within the single-stage membrane process was determined to cause a log-logistic two-and-a-half-minute delay.

No description available.

In the fields of water safety, food safety, and public communications, the overarching goal is to improve public health. Thus, this dissertation focuses on risk assessment and applying novel methods for exposure assessments and dose responses to contaminants in drinking water and foods. Factors that greatly impact contaminant exposures and human dose response include: population susceptibility (i.e., healthy adults or children), different routes of exposures (i.e., ingestion or inhalation), carrier matrices (i.e., water or food), and intricacies of chemical and biological mixtures. Chemical spills, such as the 2014 crude MCHM spill in Charleston, WV, revealed the complexities of both minor and major components in the chemical mixture. Slight shifts in geometric structures (isomers) can affect the fate and transport properties of the chemical mixture and as a result, the level of human exposure and dose response to each component in the chemical mixture. Odorous properties of both minor and major components can affect human inhalation exposure, especially during showering, and can be as detrimental as the ingestion route exposure and are different for healthy adults versus for children. Food contaminants, such as Shiga toxin producing Escherichia coli (STEC) in beef products, can be mitigated through a quantitative microbial risk assessment (QMRA) framework that follows a farm-to-fork model. Methods to ensure greatest microbial reduction include: employed intervention strategies at slaughter plants (i.e., water washing of beef carcass), improved cooking times and temperature methods at the consumer and retail level, and assessed minimum effective dose response modeling for different population susceptibilities. Current public communication tools, including the Drinking Water Taste-and-Odor Wheel or Consumer Confidence Reports (better known as water quality reports), should be redeveloped to uphold water safety. Furthermore, public health campaigns that uses social media strategies and informative websites can better educate the public on food contaminants. Ultimately, the objective is to prevent human illnesses due to water contaminants and foodborne pathogens and to bridge the communication gap between the consumers and the experts concerned with water and food safety. / Ph. D. / In the fields of water safety, food safety, and public communications, the overarching goal is to improve public health. Thus, this dissertation focuses on risk assessment and applying novel methods for exposure assessments and dose responses to contaminants in drinking water and foods. Factors that greatly impact contaminant exposures and human dose response include: population susceptibility (i.e., healthy adults or children), different routes of exposures (i.e., ingestion or inhalation), carrier matrices (i.e., water or food), and intricacies of chemical and biological mixtures. Chemical spills, such as the 2014 crude MCHM spill in Charleston, WV, revealed the complexities of both minor and major components in the chemical mixture. Slight shifts in geometric structures (isomers) can affect the fate and transport properties of the chemical mixture and as a result, the level of human exposure and dose response to each component in the chemical mixture. Odorous properties of both minor and major components can affect human inhalation exposure, especially during showering, and can be as detrimental as the ingestion route exposure and are different for healthy adults versus for children. Food contaminants, such as Shiga toxin producing Escherichia coli (STEC) in beef products, can be mitigated through a quantitative microbial risk assessment (QMRA) framework that follows a farm-to-fork model. Methods to ensure greatest microbial reduction include: employed intervention strategies at slaughter plants (i.e., water washing of beef carcass), improved cooking times and temperature methods at the consumer and retail level, and assessed minimum effective dose response modeling for different population susceptibilities. Current public communication tools, including the Drinking Water Taste-and-Odor Wheel or Consumer Confidence Reports (better known as water quality reports), should be redeveloped to uphold water safety. Furthermore, public health campaigns that uses social media strategies and informative websites can better educate the public on food contaminants. Ultimately, the objective is to prevent human illnesses due to water contaminants and foodborne pathogens and to bridge the communication gap between the consumers and the experts concerned with water and food safety.

No / Drinking water disinfection byproducts (DBPs) are generated by the chemical disinfection of water and may pose a hazard to the public health. Previously we demonstrated that iodoacetic acid was the most cytotoxic and genotoxic DBP analyzed in a mammalian cell system. Little is known of the mechanisms of its genotoxicity. The involvement of oxidative stress in the toxicity of iodoacetic acid was analyzed with the antioxidants catalase and butylated hydroxyanisole (BHA). Iodoacetic acid toxicity was quantitatively measured with and without antioxidants in Salmonella typhimurium strain TA100 and with Chinese hamster ovary (CHO) cells. The endpoints included cytotoxicity in S. typhimurium or in CHO cells, mutagenicity in S. typhimurium, and genotoxicity in CHO cells. Neither catalase nor BHA reduced the level of iodoacetic acid induced cytotoxicity in S. typhimurium. In CHO cells neither antioxidant caused a significant reduction in iodoacetic acid induced cytotoxicity. However, in S. typhimurium, BHA or catalase reduced the mutagenicity of iodoacetic acid by 33.5 and 26.8%, respectively. Likewise, BHA or catalase reduced iodoacetic acid induced genomic DNA damage by 86.5 and 42%, respectively. These results support the hypothesis that oxidative stress is involved in the induction of genotoxicity and mutagenicity by iodoacetic acid.