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7 pp. / Agriculture is by far the largest water-demanding sector in Arizona, accounting for 70% of water demand (ADWR, 2009). Arizona’s agriculture industry is extremely diversified, producing many crops that can legally be irrigated with recycled water, including cotton, alfalfa, wheat, citrus, and vegetables. Throughout the State, farming communities are taking advantage of increasing supplies of recycled water.

Water reuse is increasingly pursued to alleviate global water scarcity. However, wastewater treatment process does not achieve full removal of biological contaminants from wastewater, and hence some microorganisms and their genetic elements can be disseminated into the reclaimed water distribution systems (RWDS). A systematic identification and characterization of these biological contaminants is required. However, a broad characterization for large-scale data are limited. In this study, reclaimed water samples are investigated through metagenomic analyses to assess their bacterial and functional (metal resistance genes (MRGs); virulence factors (VFs)) communities at the entry and exit points of the RWDS. Furthermore, water quality data are investigated to evaluate the potential relationship with these metagenomic annotations. This study found that the organic carbon content was likely relevant to the increase of bacteria and functional genes in RWDS. It was also found that the variation of functional genes was not associated with their host, inferring the role of horizontal gene transfers or promiscuity of hosts for various functional genes. Furthermore, Pseudomonas was identified in one RWDS with significant increase at both bacterial and functional levels.

The goal of this study was to assess the effect of residence time on the chemical and microbial quality of reclaimed water in two distribution systems located in southern Arizona. Utility A produced Class A water and utilized chlorine as a means of disinfection whereas Utility B produced Class A+ water and utilized UV radiation as a means of disinfection. Water-based pathogens were consistently detected in both distribution systems beyond the point of compliance, while microbial indicators like Escherichia coli was only detected in Utility B suggesting that treatment eliminated waterborne pathogens. Heterotrophic plate concentrations in samples from both utilities initially increased rapidly with increased distance from the point-of-compliance and were as high as 10⁹ CFU/100ml. Regardless of the initial level of treatment, the microbial quality deteriorated with increased residence time in the distribution systems. The second study was designed to evaluate the effect of reclaimed water storage on microbial and chemical quality of two classes of reclaimed water (Class A and Class A+). In Class A water, nitrification was observed during both field scale trials resulting in concentrations greater than 10mg/L while nitrification was not observed in Class A+. Chlorine residuals rapidly decreased within 48hours of storage. HPC concentration were as high as 10⁷ - 10⁸ /100ml. In both field scale trials, there was no observed growth of HPC during storage and waterborne indicator bacteria were rarely detected, and if detected, only at low concentrations. Based on this data, deterioration of microbial water quality during storage is minimal.

With the ever increasing demand for potable water due to the continued increase in population coupled with the threat of California’s current drought, water will remain a limited resource that must be managed responsibly. In order to strategically plan and manage water use in the most beneficial manner, water providers must take into account all sources of water, including recycled water and their applications. Recycled water as a source for supplementing high quality potable water is a sustainable strategy that will prove to be an essential tactic in any water management plan. The purpose of this project is to emphasize the importance of supplementing potable water in the City of Banning by discussing the characteristics of California’s current water drought; evaluating the City of Banning’s available water supplies and current water demand; discussing the Soil Aquifer Treatment process; summarizing California’s regulations related to recycled water; and discussing the quality of recycled water available at NP-1, an unequipped City owned water well, by examining water quality testing on water samples taken from NP-1. Analysis of water available at NP-1 showed that with additional disinfection, the water pumped from NP-1 could meet the recycled water requirements in order to be used on a local golf course. The local golf course is currently being irrigated with potable water, which would be supplemented with the recycled water from NP-1.

Os vírus entéricos humanos são encontrados no esgoto e em subprodutos dos processos de tratamento. Recentemente vem sendo recomendados como indicadores de qualidade microbiológica em normas da legislação brasileira e também nas de outros países, mas ainda com parâmetros a definir. O objetivo do estudo é a avaliação e a comparação entre métodos clássicos e moleculares aplicados à detecção de vírus entéricos em amostras de água de reúso e de lodo, visando subsidiar a legislação brasileira. Ensaios de semeadura experimental de protótipos de rotavírus e de adenovírus foram realizados nas matrizes ambientais e os vírus detectados por métodos clássicos (cultivo celular e reação de imunoperoxidase) e moleculares (PCR/nested-PCR, RT-PCR e ICC-PCR), determinando-se os limites de detecção de cada método para cada matriz. A pesquisa de rotavírus e adenovírus presentes naturalmente em 25 amostras de água de reúso e em 25 de lodo possibilitou a comparação dos métodos propostos. O ICC-PCR mostrou ser o método mais factível a ser aplicado na área de saneamento. / Human enteric viruses are common contaminants of raw sewage and subproducts of sewage treatment processes. In recent years, those viruses were recommend as new microbiological indicators in different matrices in Brazilian legislation and others countries, although some questions should be elucidated. At present, the aim was to evaluate and compare the efficiencies of standard and molecular virological methods for detection of human enteric viruses in sludge and reclaimed water samples. Rotavirus and adenovirus were experimentally spiked in the proposed matrices and virus recovery and detection limits established for each method and matrice. Viruses naturally presented in 25 samples of sludge and 25 samples of reclaimed water were assayed by all methods and results evaluated and compared for statistical significance. From all methods evaluated, ICC-PCR showed to be the most suitable for virus surveillance in sludge and reclaimed water.

Monitoring viruses circulating in the human population and the environment is critical for protecting public and ecosystem health. The goal of this dissertation was to incorporate a viral metagenomic approach into virus surveillance efforts (both clinical and water quality control programs) to enhance traditional virus detection methods. Clinical surveillance programs are designed to identify and monitor etiological agents that cause disease. However, the ability to identify viruses may be compromised when novel or unsuspected viruses are causing infection since traditional virus detection methods target specific known pathogens. Here we describe the successful application of viral metagenomics in a clinical setting using samples from symptomatic patients collected through the Enterovirus Surveillance (EVS) program in the Netherlands (Appendix A). Despite extensive PCR-based testing, the viruses in a small percentage of these samples (n = 7) remained unidentified for more than 10 years after collection. Viral metagenomics allowed the identification of viruses in all seven samples within a week using minimal sequencing, thus rapidly filling the diagnostic gap. The unexplained samples contained BK polyomavirus, Herpes simplex virus, Newcastle disease virus and the recently discovered Saffold viruses (SAFV) which dominated the unexplained samples (n = 4). This study demonstrated that metagenomic analyses can be added as a routine tool to investigate unidentified viruses in clinical samples in a public-health setting. In addition, metagenomic data gathered for SAFV was used to complete four genotype 3 SAFV (SAFV-3) genomes through primer walking, doubling the number of SAFV-3 full genomic sequences in public databases. In addition to monitoring viruses in symptomatic patients, it is also important to monitor viruses in wastewater (raw and treated) to protect the environment from biological contamination and prevent further spread of pathogens. To gain a comprehensive understanding of viruses that endure wastewater treatment, viral metagenomics was used to survey the total DNA and RNA viral community in reclaimed water (the reusable end-product of wastewater treatment) (Appendix B). Phages (viruses that infect bacteria) dominated the DNA viral community while eukaryotic viruses similar to known plant and insect viruses dominated RNA metagenomic libraries suggesting that highly stable viruses may be disseminated through this alternative water supply. A plant virus, the Pepper mild mottle virus (PMMoV), was identified as a potential indicator of wastewater contamination based on metagenomic data and quantitative PCR assays (Appendix C). The metagenomic analysis also revealed a wealth of novel single-stranded DNA (ssDNA) viruses in reclaimed water. Further investigation of sequences with low-level similarities to known ssDNA viruses led to the completion of ten novel ssDNA genomes from reclaimed water and marine environments (Appendix D). Unique genome architectures and phylogenetic analysis suggest that these ssDNA viruses belong to new viral genera and/or families. To further explore the ecology of the novel ssDNA viruses, a strategy was developed to take metagenomic analysis to the next level by combining expression analysis and immunotechnology (Appendix E). This dissertation made a significant contribution to current microbiological data regarding wastewater by uncovering viruses that endure the wastewater treatment and identifying a new viral bioindicator.

The energy-water nexus represents a complex system of correlated resources, with particular relevance to thermoelectric power plants. Since thermoelectric power plants typically depend on water for cooling, these facilities are prone to water-related challenges. At the same time, large water withdrawals for power plants can adversely impact other water users in a watershed. This work aims to evaluate water impacts on Texas power plant operations and the associated effects these power plants have on water availability. An evaluation of the water impacts on power generation in Texas was completed through four analyses: 1) water availability effects of changing cooling technologies, 2) economic value of drought resiliency through use of alternative cooling technologies, 3) dynamic impacts of reservoir storage on power generation operations, and 4) potential for reclaimed water as a cooling source. Based on the results of these analyses, the following general conclusions were drawn [bulleted list]: [bullet] Use of alternative cooling technologies decreases water withdrawals at the expense of additional energy and water consumption. However, the reduced withdrawals for power plants leaves more water in the stream for other water users, including instream flows. [bullet] Alternative cooling technologies incur additional capital costs, but gain value from reduced water withdrawals. The lower withdrawal requirements make such facilities more resilient to drought, which can have economic value from additional generation during possible drought-related curtailment or suspension. [bullet] Changing surface water reservoir storage at power plants has dynamic impacts on power generation operations, as well as other users in a river basin. Generally, decreasing power plant reservoir storage benefits other users in the basin. Instances arise where both beneficial and detrimental impacts are also observed. [bullet] Reclaimed water can be a technologically and economically feasible cooling source for many existing power plants. The future suitability of using reclaimed water for power plant cooling depends on water pipeline construction costs, reclaimed water flow, and water stress [end of bulleted list]. These general conclusions, along with further details, provide insight into the relationship between water resources and thermoelectric power plants. As resources become increasingly strained, understanding and responding to tradeoffs within the energy-water nexus, through such analyses, might become imperative for sustainable resource management. / text

Os vírus entéricos humanos são encontrados no esgoto e em subprodutos dos processos de tratamento. Recentemente vem sendo recomendados como indicadores de qualidade microbiológica em normas da legislação brasileira e também nas de outros países, mas ainda com parâmetros a definir. O objetivo do estudo é a avaliação e a comparação entre métodos clássicos e moleculares aplicados à detecção de vírus entéricos em amostras de água de reúso e de lodo, visando subsidiar a legislação brasileira. Ensaios de semeadura experimental de protótipos de rotavírus e de adenovírus foram realizados nas matrizes ambientais e os vírus detectados por métodos clássicos (cultivo celular e reação de imunoperoxidase) e moleculares (PCR/nested-PCR, RT-PCR e ICC-PCR), determinando-se os limites de detecção de cada método para cada matriz. A pesquisa de rotavírus e adenovírus presentes naturalmente em 25 amostras de água de reúso e em 25 de lodo possibilitou a comparação dos métodos propostos. O ICC-PCR mostrou ser o método mais factível a ser aplicado na área de saneamento. / Human enteric viruses are common contaminants of raw sewage and subproducts of sewage treatment processes. In recent years, those viruses were recommend as new microbiological indicators in different matrices in Brazilian legislation and others countries, although some questions should be elucidated. At present, the aim was to evaluate and compare the efficiencies of standard and molecular virological methods for detection of human enteric viruses in sludge and reclaimed water samples. Rotavirus and adenovirus were experimentally spiked in the proposed matrices and virus recovery and detection limits established for each method and matrice. Viruses naturally presented in 25 samples of sludge and 25 samples of reclaimed water were assayed by all methods and results evaluated and compared for statistical significance. From all methods evaluated, ICC-PCR showed to be the most suitable for virus surveillance in sludge and reclaimed water.

A water supply plan approach was used to investigate irrigation application on landscaped areas in Virginia with a focus on turfgrass. The economically-important turfgrass industry in Virginia should be proactive in conserving drinking water supplies to meet human consumption needs, especially in drought times. This thesis investigates current irrigation water supplies, water supply sustainability, and alternative water sources to meet irrigation demands and offers an insight on how potable water is unnecessarily consumed for non-potable irrigation needs. A Virginia evapotranspiration website was developed to offer a scientifically based source for efficient irrigation scheduling. The website was developed using a collaborative and user-centered design method, which included potential users in the process. The final website is hosted on the Virginia Tech website at http://www.turf.cses.vt.edu/Ervin/et_display.html and utilizes data from weather stations throughout the state. Evapotranspiration-based irrigation was tested at three case study sites in Blacksburg, Williamsburg and Norfolk, Virginia to assess potential water conservation. In Williamsburg, a 55% water savings was reported with evapotranspiration-based irrigation. In Blacksburg, slightly more water was applied on research greens irrigated based on evapotranspiration demand. Significantly less water was applied in Norfolk, compared to the evapotranspirationbased irrigated plots. The study also uncovered increased confidence to alter irrigation systems and the need to conduct irrigation audits when irrigating based on evapotranspiration. Evapotranspiration-based irrigation, reclaimed water and harvested rainwater were investigated to determine feasibility for meeting irrigation demands, while reducing potable water consumption at four case study sites in Blacksburg, Fairfax, Williamsburg and Norfolk, Virginia. Due to the limited collection potential at the Blacksburg site, reclaimed water and harvested rainwater was not feasible. However, the on-site weatherstation could offer a unique opportunity to calculate evapotranspiration. In Fairfax, all three alternative water sources could be integrated to supply enough water to irrigate a soccer field and adjacent athletic fields and save an estimated $7,000 per season in potable water costs. Harvested rainwater at the Williamsburg site could supplement the irrigation pond and reduce reliance on groundwater. In Norfolk, reclaimed water use is economically feasible, but rainwater harvesting could meet the irrigation needs, while evapotranspiration-based irrigation is too labor intensive for homeowners. / Ph. D.