Recent droughts and heat waves have revealed the vulnerability of some power plants to effects from higher temperature intake water for cooling. Climate projections estimate higher air temperatures in future years, indicating that these problems could increase. This research seeks to understand the magnitude of influence that higher temperatures will have on power plant effluent water temperatures to quantify a power plant's exposure to risk of de-rating induced by low or warm cooling water availability. The objective of this analysis is to help policymakers and plant operators plan for future electricity supplies without damaging the natural environment of the cooling reservoirs and rivers. This objective is met via assessment of water constraints associated with current technology, policy, and environmental conditions in two river basins, the Gulf Coast Basin in Texas and the Upper Mississippi River Basin in the Midwestern United States. Risk of reduced operations at these power plants associated with thermal discharge limits is then assessed by estimating intake and effluent water temperatures and comparing these estimates to current restrictions. Of the thirty-three plants analyzed, none are estimated to exceed effluent temperature limits within the study period of 2015 to 2035. However, twelve power plants could face increasing intake temperatures, leading to potential issues with cooling efficiency. Fourteen plants could discharge slightly higher effluent temperatures, possibly influencing the ecosystem of the return water body upon discharge beyond today's impacts. To help with planning for future issues, this analysis also identifies many of the ways by which power plants mitigate issues with low water levels and high temperatures. Designing plants for potentially scarce water resources and making policies that protect water supplies and support energy resources could be beneficial in coming years. This research is intended to inform that objective. / text

Using Ningxia Hui Autonomous Region in China as a case study, the thesis addresses the interconnectedness between water and energy and investigates the regional water-energy nexus to assess the coherence of relevant policies and to explore opportunities to achieve sustainable development. Ningxia is extremely scarce in water but abundant in coal. On one hand, the government sets stringent targets to conserve water; on the other hand, the region has ambitious plans to develop the water intensive coal and relevant industries. Based on current development status and policies, the water and energy systems are modeled by WEAP and LEAP, respectively. The regional water-energy nexus is mapped to reveal the interactions between water and energy sectors. From the water policies, it is estimated that the water demand would decrease slightly in 2015; from the energy policies, the energy demand and production would increase greatly. Through the nexus approach, it is found that while energy is abundant to satisfy the increasing demand by the water sector for production and supply, water, however, cannot support the aggressive energy development. The huge water deficit indicates the potential incoherence of current policies and the unsustainable development mode. Nevertheless, there are opportunities to secure resources sustainability. This thesis highlights the viability of the water-energy nexus approach for comprehensive cross-sectorial assessment in policy making and resource management.

abstract: Local municipalities in the Phoenix Metropolitan Area have voiced an interest in purchasing alternate source water with lower DBP precursors. Along the primary source is a hydroelectric dam in which water will be diverted from. This project is an assessment of optimizing the potential blends of source water to a water treatment plant in an effort to enable them to more readily meet DBP regulations. To perform this analysis existing water treatment models were used in conjunction with historic water quality sampling data to predict chemical usage necessary to meet DBP regulations. A retrospective analysis was performed for the summer months of 2007 regarding potential for the WTP to reduce cost through optimizing the source water by an average of 30% over the four-month period, accumulating to overall treatment savings of $154 per MG ($82 per AF). / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2011

Freshwater scarcity and clean energy shortage are two grand challenges to global sustainable development. The inextricably interconnected water-energy nexus is being increasingly felt globally owing to the massive water used for electricity generation and huge amount of energy consumed in water desalination. This dissertation investigated the utilization of the waste heat of the solar cell to produce fresh water. This is achieved by constructing a multistage membrane distillation device (MSMD) at the backside of the solar cell to efficiently utilize its heat and it is capable of recycling the latent heat of the vapor condensation in each distillation stage. The first generation photovoltaic-membrane distillation (PV-MD) device exhibits a clean water production rate of 1.64 kg/m2 h with the solar cell temperature of 58 oC in a 3-stage device under one-sun radiation. However, some concentrated seawater can be produced from the PV-MD owing to its cross-flow design. To this end, an evaporative crystallizer is designed beneath the PV-MD, which can reuse the low-grade latent heat of vapor condensation in the last stage of the MSMD to evaporate the produced concentrated seawater, realizing zero liquid discharge. In addition, a theoretical model was also established to enhance the clean water production rate and reduce the solar cell temperature, which guides us to select a hydrophobic membrane with a thickness of 0.1 mm and porosity of 0.86 to fabricate the second generation photovoltaic-membrane distillation-evaporative crystallizer (PV-MD-EC) device. We experimentally demonstrate that a 5-stage PV-MD-EC device can desalinate seawater at a rate of ~2.45 kg m-2 h-1 with a lower solar cell temperature of ~48oC. The electricity generation efficiency of the solar cell is also enhanced by ~8% owing to its reduced temperature. A trade-off exists between the clean water production performance and material cost of the MSMD because a higher energy efficiency is at the expense of more stages applied. A low-cost and highly flexible 8-stage paper-based MSMD (P-MSMD) is further designed and fabricated and it showed a clean water production rate of 3.61 kg/m2 h for seawater desalination. This work sheds light on the design and fabrication of a composite system capable of achieving the simultaneous production of electricity and clean water with solar energy as an only energy source. Owing to their low barrier of entry, the devices reported in this dissertation are well suited to provide off-grid electricity and freshwater in a decentralized manner for point of consumption locations especially off-grid communities and communities with small- to medium-sized population even with challenging economic conditions.

Viele Länder des globalen Südens erleben aktuell die doppelte Dynamik von rasanter Urbanisierung und globaler Umweltveränderung. Die Schaffung nachhaltiger und widerstandsfähiger Städte ist ein globales Ziel der UN (SDG11). Die Urbanisierung wird mit zahlreichen Vorteilen auf gesellschaftlicher und individueller Ebene in Verbindung gebracht. Gleichzeitig birgt sie jedoch negative Auswirkungen auf die natürlichen Ressourcen, kann städtische Versorgungssysteme überfordern und neue Verwundbarkeiten schaffen. Da die verschiedenen Herausforderungen miteinander verknüpft sind, bedarf es eines interdisziplinären Forschungsansatzes. Im Laufe des letzten Jahrzehnts hat sich der Food-Water-Energy (FWE)-Nexus für sektorübergreifende Analysen etabliert. In dieser Dissertation wird ein Beitrag zum Verständnis des FWE-Nexus in schnell urbanisierenden Regionen des globalen Südens geleistet und es werden Defizite in der aktuellen Debatte adressiert. Im Mittelpunkt der Arbeit steht die Millionenstadt Pune in Indien. Um ein umfassendes Systemverständnis zu erlangen, wird in Zusammenarbeit mit lokalen Stakeholdern zunächst eine Sammlung von 22 FWE-Herausforderungen auf verschiedenen Ebenen erstellt. In den anschließenden vertieften Analysen werden ausgewählte urbanisierungsbezogene Herausforderungen untersucht, insbesondere die zukünftige Entwicklung des Stadtwachstums und die Zuwanderung nach Pune. Letztere ist einer der wichtigsten Wachstumstreiber. Zu diesem Zweck wird ein neuartiger Modellierungsansatz vorgestellt, bei dem nationale sozioökonomische Szenarien auf die Stadtebene herunterskaliert, und in räumlich explizite Darstellungen von bebauter Fläche und Bevölkerungsdichte übersetzt werden. Diese erlauben Analysen potenzieller FWE-Nexus-Herausforderungen in Zukunft. Die Untersuchung der Zuwanderung nach Pune basiert auf qualitativen und quantitativen Datenquellen mittels Mixed-Methods-Verfahren. Das in allen Szenarien erwartete signifikante Stadtwachstum ist mit einer Konzentration des Ressourcenbedarfs in der Stadt, einem erheblichen Verlust an fruchtbarem Land und einer Zunahme von Überschwemmungsrisiken verbunden. In Bezug auf Zuwanderung nach Pune spielt der Klimawandel in Form von Dürren eine signifikante, wenn auch unterbelichtete, Rolle. Neuankömmlinge, die aus dem ländlichen Raum oder aus anderen Bundesländern stammen, sowie jene, die gegenwärtig in informellen Siedlungen leben, waren zum Zeitpunkt der Migrationsentscheidung überproportional stark von Dürren betroffen. Die Analysen beleuchten die bidirektionalen Verflechtungen zwischen Urbanisierung und FWE-Nexus-Aspekten: Die wachsende Stadt ist bereits heute Treiber und zugleich Leidtragende von FWE-Nexusproblemen. Diese müssen umfassend angegangen werden, um Wege zu einer nachhaltigen und resilienten urbanen Zukunft zu sichern.:1. General Introduction: Context, Approach, and Summary of Results 1.1. Background and Research Motivation 1.2. Case study site Pune 1.3. Knowledge Gaps 1.4. Problem Definition and Research Questions 1.5. Research Approach and Methodological Overview 1.5.1. Identification of the main sustainability challenges related to urbanization 1.5.2. Modeling of future urban growth 1.5.3. In-depth investigation of mobility to Pune 1.5.4. Integration 1.6. Summary and Linking of Results 1.6.1. Results of Paper 1 1.6.2. Results of Paper 2 1.6.3. Results of Paper 3 1.7. Discussion 1.8. Conclusion and Outlook Paper 1: Capturing Stakeholders’ Challenges of the Food–Water–Energy Nexus— A Participatory Approach for Pune and the Bhima Basin, India Paper 2: On Farmland and Floodplains – Modeling Urban Growth Impacts Based on Global Population Scenarios in Pune, India Paper 3: Exploring the Relationship Between Droughts and Rural-to-urban Mobility – a Mixed-Methods Approach for Pune, India Appendix / Many countries in the global South are experiencing the combined dynamics of rapid urbanization and global environmental change. The provision of sustainable and resilient cities is a declared global goal (SDG11). Urbanization has been associated with multiple benefits on societal and individual level. However, it can also entail adverse impacts on natural resources, overstrain supply systems, and create new vulnerabilities. The interlinked nature of challenges requires an interdisciplinary research approach. Over the last decade, the Food-Water-Energy (FWE) nexus has been popularized for inter-sectoral analyses. This thesis attempts to add to the understanding of the FWE nexus in rapidly urbanizing regions of the global South and to address shortcomings in the current debate. The work is centered around the emerging megacity of Pune in India. For a comprehensive understanding of the system under investigation, a set of 22 FWE challenges on various levels is co-produced with local stakeholders. Subsequent analyses investigate selected urbanization-related challenges in-depth, namely future trajectories of the city’s growth and in-migration as one of its main drivers. To that end, a novel modeling approach is presented, downscaling established high-level socioeconomic scenarios to the city level and translating them into built-up area mapped by a cellular automaton. Population surfaces are then generated via dasymetric mapping. The resulting spatial configurations of built-up and population scenarios are analyzed in terms of potential FWE nexus challenges. The analysis of in-migration to Pune is based on qualitative and quantitative data sources and their mixed methods analysis. The significant demographic, economic, and spatial growth expected in all scenarios is associated with a concentration of resource demands in the city, significant loss of fertile land, and an increase in flood-affected population and infrastructure. As to in-migration, climate change has played a role in mobility to Pune in the form of droughts, especially for recent arrivals. Rural-origin migrants, those who came from other states, and who currently live in informal settlements were disproportionately affected by droughts at origin. The results shed light on the bidirectional interlinkages between urbanization and FWE nexus issues: Today already, the growing city of Pune drives, and suffers from, nexus challenges. These have to be addressed comprehensively in order to secure pathways to a sustainable and resilient urban future.:1. General Introduction: Context, Approach, and Summary of Results 1.1. Background and Research Motivation 1.2. Case study site Pune 1.3. Knowledge Gaps 1.4. Problem Definition and Research Questions 1.5. Research Approach and Methodological Overview 1.5.1. Identification of the main sustainability challenges related to urbanization 1.5.2. Modeling of future urban growth 1.5.3. In-depth investigation of mobility to Pune 1.5.4. Integration 1.6. Summary and Linking of Results 1.6.1. Results of Paper 1 1.6.2. Results of Paper 2 1.6.3. Results of Paper 3 1.7. Discussion 1.8. Conclusion and Outlook Paper 1: Capturing Stakeholders’ Challenges of the Food–Water–Energy Nexus— A Participatory Approach for Pune and the Bhima Basin, India Paper 2: On Farmland and Floodplains – Modeling Urban Growth Impacts Based on Global Population Scenarios in Pune, India Paper 3: Exploring the Relationship Between Droughts and Rural-to-urban Mobility – a Mixed-Methods Approach for Pune, India Appendix

This dissertation assesses the long-term technological and policy implications of adapting to water constraints and climate change impacts in the energy sector. Energy systems are increasingly vulnerable to climate change and water resource variability. Yet, the majority of long-term energy infrastructure plans ignore adaptation strategy. New analytical approaches are needed to address the spatial and temporal scales relevant to both climate change and water resources. The research in this dissertation overcomes these challenges with improved engineering-economic modeling. Specifically, the conventional systems-engineering energy technology planning framework is extended to incorporate: (1) robust capacity decisions in the electricity sector in light of impacts from hydro-climatic change and uncertain environmental performance of technology options; (2) an endogenous, spatially-distributed representation of water systems and feedbacks with energy demand; and (3) multi-objective decision-making. The computational modeling framework is applied to four regional case study analyses to quantify previously unaccounted for policy-relevant interactions between water, energy and climate systems. Application of the robust adaptation planning framework to the power system in British Columbia, Canada, reveals technology configurations offering long-term operational flexibility will be needed to ensure reliability under projected climate change impacts to provincial hydropower resources and electricity demand. The imposed flexibility requirements affect the suitability of technology options, and increases the cost of long-term electricity system operation. The case study analysis then focuses on the interaction between groundwater conservation and concurrent policy aimed at reducing electricity sector carbon emissions in the water-stressed country of Saudi Arabia. Application of the novel water-energy infrastructure planning framework reveals that transitioning away from non-renewable groundwater use by the year 2050 could increase national electricity demand by more than 40 % relative to 2010 conditions, and require investments similar to strategies aimed at transitioning away from fossil fuels in the electricity sector. The research in this dissertation demonstrates the crucial need for regional planners to account for adaptation to climate change and water resource constraints when developing long-term energy strategy. / Graduate

Notions of connectivity and relationality increasingly pervade theories, discourses and practices of environmental governance. Recently, the concept of the 'resource nexus' has emerged as an important new framework that emphasises the interconnections, tensions and synergies between sectors that have traditionally been managed separately. Part of a broader trend towards integrated environmental governance, nexus thinking rests on the premise that the challenges facing water, energy, food and other resources are inexorably connected and contingent. Although presenting itself as a radically new framework, the nexus discourse in current form is techno-managerial in character, profoundly de-politicising, and reinforces neoliberal approaches to environmental governance. At the same time, the 'material turn' in social science research has re-engaged ideas of social, political and material relationality to understand the complexity and heterogeneity of the socio-natural condition in the twenty-first century. Although theoretically and ontologically diverse, the fields of political ecology, assemblage thinking and infrastructure studies all critically interrogate the politics of relationality. Mobilising an urban political ecology framework, and drawing on notions of emergence and distributed agency from assemblage thinking, this research examines the politics of the water-energy nexus through a critical analysis of the extraordinary emergence of seawater desalination as a significant new urban water supply for Southern California, USA, and Baja California, Mexico. Research was conducted in the San Diego-Tijuana metropolitan region, where a large desalting facility has recently been completed to supply San Diego with purified ocean water, and a larger 'binational' facility is planned in Mexico to supply both sides of the border. The research makes three broad contributions. First, to understand desalination as emerging from the historical coproduction and urbanisation of water and energy in the American West. Second, to examine the transitioning environmental politics concomitant with calls for greater understanding of interrelationality. And third, to interrogate the efficacy of technology in reconfiguring the co-constitution of water, energy and society.

Water and electricity are fundamentally linked. Policy reforms in both industries, however, do not appear to acknowledge the links nor consider their wider implications. This is clearly unhelpful, particularly as policy makers attempt to develop effective responses to water and energy issues, underpinned by prevailing drought conditions and impending climate change. Against this backdrop, this research has comprehensively analysed the links between water and electricity – termed water-energy nexus – in the context of New South Wales. For this purpose, this research has developed an integrated methodological framework. The philosophical guidance for the development of this framework is provided by Integral Theory, and its analytical foundations rest on a suite of research methods including historical analysis, inputoutput analysis, analysis of price elasticities, and long-term scenario analysis. This research suggests that the historical and inextricable links between water and electricity, in the absence of integrated policies, has given rise to water-energy trade-offs. In the electricity industry, water-intensive coal-fired power stations that dominate base-load capacity in the National Electricity Market has resulted in intra- and inter-jurisdictional water sharing tradeoffs. Intermediate and peak demand technologies, suchas gas-fired, cogeneration and renewables, however, would significantly reduce the industry’s water consumption and carbon emissions. Drought and climate change adaptation responses in the water industry are likely to further increase electricity demand andpotentially contribute to climate change, due to policies that encourage investment in energy-intensive technologies, such as desalination, advanced wastewater treatment and rainwater tanks. Increasing electricity costs due to water shortages and the introduction of emissions trading will futher increase water and electricity prices for end users. Demand management strategies in both industries will assist in curbing price increases, however, their effectiveness is lessened by investment in water- and energy-intensive technologies in both industries. The analysis also demonstrates that strategies to reduce water and electricity consumption of ‘other’ production sectors in New South Wales is overwhelmingly dependent on how deeply a particular sector is embedded in the economy, in terms of its contribution to economic output, income generation and employment growth. Regulation, demand management programs, and water pricing policies, for example, that reduce the water and energy intensity of agriculture and key manufacturing sectors are likely to benefit the wider economy and the Environment. The future implications of the water-energy nexus are examined through long-term scenario analysis for New South Wales for 2031. The analysis demonstrates how policy decisions shape the domain for making philosophical choices by society - in terms of the balance between relying on alternative technologies and market arrangements, with differing implications for water and electricity use, and for instigating behavioural change. Based on these findings, this research puts forward a range of recommendations, essentially arguing for reorienting existing institutional arrangements, government measures and industry activities in a way that would encourage integration between the water and energy policies. Although the context of this research is New South Wales, the findings are equally relevant for other Australian states, which share the same national water and energy policy frameworks. Further, the concepts and frameworks developed in this research are also of value to other countries and regions that are faced with the task of designing appropriate policy responses to redress their water and energy challenges.

An innovative wastewater treatment technology was developed to recover renewable resources, such as water, energy and nutrients, from sewage. First, a novel synthetic sewage was evaluated for its suitability to serve as an alternative substrate for lab-scale wastewater treatment (WWT) research. Based on granular dried cat food, Complex Organic Particulate Artificial Sewage (COPAS) is a commercially-available, flexible, and easy to preserve feed. Characteristics of COPAS, namely chemical composition, disintegration/dissolution kinetics, and anaerobic biodegradability, were determined. Anaerobic bioassays indicate that COPAS is highly biodegradable at the concentration used to simulate household sewage (1000 mg/L), with more than 72% of the theoretical methane content reached after 30 d of incubation. Results indicate that COPAS is a suitable substrate as a surrogate of domestic sewage. In the second stage of the research, a lab-scale, 10L gas-lift anaerobic membrane bioreactor (Gl-AnMBR) was designed, fabricated and tested. The AnMBR is a hybrid treatment technology that combines anaerobic biological treatment with low-pressure membrane filtration. Although AnMBR has been used in many instances for the treatment of high strength industrial or agricultural wastewater, relatively little has been reported about its application for the treatment of domestic sewage and further conversion and recovery of resources embedded in sewage, such as energy and nutrient enriched water. The 10L column reactor uses a tubular PVDF ultrafiltration membrane (with biogas as sparge gas) for sludge/water separation. COPAS was used as synthetic feed (at 1000 mg/L) to represent household wastewater. The configuration showed excellent removal efficiencies of organic matter (up to 98% and 95% in COD and TOC removal, respectively) while producing energy in the form of methane at quantities suitable for maintaining membrane scrubbing (4.5 L/d of biogas). Soluble nutrients were recovered in the effluent in the forms of NH4, (9.1±4.2 mg/L), NO3 (2.2±0.9 mg/L) and PO4 (20±7.13 mg/L). The energy footprint (net energy) of this reactor was evaluated and the energy requirements per volume of permeate produced was found to be in the range of -1.2 to 0.7 kWh/m3, depending on final conversion of methane to electric or thermal energy respectively. These values could potentially be improved towards energy surplus (-2.3 to -0.5 kWh/m3) if applied to plant scale operation, which would employ more efficient pumps than those used in the lab. Results from this study suggest that the Gl-AnMBR can be applied as a sustainable treatment tool for resource recovery from sewage, which can further be optimized for large scale operation. In the final stage of this research, further resource recovery from sewage was investigated by coupling the Gl-AnMBR with an innovative gas-lift algal photo MBR (APMBR). To our knowledge, this is the first reported application of membranes (in particular gas-lift tubular) for separation of algal cells from effluent in a continuous-flow photobioreactor. Nutrient rich effluent (9 mg/L NH4-N and 20 mg/L PO4-P) from the Gl-AnMBR treating domestic wastewater was used as substrate to grow the biofuel producing microalgae Chlorella sorokiniana (Cs). The initial set of operational conditions tested in this study (HRT of 24 hours, operational flux of 4.5 LMH, air-lift flow rate (Qa) of 0.1 L/min and 0.1 bars of membrane inlet pressure), achieved 100% removal efficiencies for NH4 and PO4. Flux remained constant during the experimental period which demonstrated the efficacy of gas lift as a membrane fouling control strategy for an algae bioreactor. Because the algae is photoautotrophic, little removal of organic carbon was expected nor observed. Further studies are required to better understand the fate and cycling of carbon in the APMBR. Limited information is available in the literature regarding biofuel-producing, algal photo MBRs utilizing anaerobic effluents as feedstock, which makes this study an important step in understanding the design and performance of combined anaerobic/algal biotechnology for large scale application of wastewater resource recovery.

Water and electricity are fundamentally linked. Policy reforms in both industries, however, do not appear to acknowledge the links nor consider their wider implications. This is clearly unhelpful, particularly as policy makers attempt to develop effective responses to water and energy issues, underpinned by prevailing drought conditions and impending climate change. Against this backdrop, this research has comprehensively analysed the links between water and electricity – termed water-energy nexus – in the context of New South Wales. For this purpose, this research has developed an integrated methodological framework. The philosophical guidance for the development of this framework is provided by Integral Theory, and its analytical foundations rest on a suite of research methods including historical analysis, inputoutput analysis, analysis of price elasticities, and long-term scenario analysis. This research suggests that the historical and inextricable links between water and electricity, in the absence of integrated policies, has given rise to water-energy trade-offs. In the electricity industry, water-intensive coal-fired power stations that dominate base-load capacity in the National Electricity Market has resulted in intra- and inter-jurisdictional water sharing tradeoffs. Intermediate and peak demand technologies, suchas gas-fired, cogeneration and renewables, however, would significantly reduce the industry’s water consumption and carbon emissions. Drought and climate change adaptation responses in the water industry are likely to further increase electricity demand andpotentially contribute to climate change, due to policies that encourage investment in energy-intensive technologies, such as desalination, advanced wastewater treatment and rainwater tanks. Increasing electricity costs due to water shortages and the introduction of emissions trading will futher increase water and electricity prices for end users. Demand management strategies in both industries will assist in curbing price increases, however, their effectiveness is lessened by investment in water- and energy-intensive technologies in both industries. The analysis also demonstrates that strategies to reduce water and electricity consumption of ‘other’ production sectors in New South Wales is overwhelmingly dependent on how deeply a particular sector is embedded in the economy, in terms of its contribution to economic output, income generation and employment growth. Regulation, demand management programs, and water pricing policies, for example, that reduce the water and energy intensity of agriculture and key manufacturing sectors are likely to benefit the wider economy and the Environment. The future implications of the water-energy nexus are examined through long-term scenario analysis for New South Wales for 2031. The analysis demonstrates how policy decisions shape the domain for making philosophical choices by society - in terms of the balance between relying on alternative technologies and market arrangements, with differing implications for water and electricity use, and for instigating behavioural change. Based on these findings, this research puts forward a range of recommendations, essentially arguing for reorienting existing institutional arrangements, government measures and industry activities in a way that would encourage integration between the water and energy policies. Although the context of this research is New South Wales, the findings are equally relevant for other Australian states, which share the same national water and energy policy frameworks. Further, the concepts and frameworks developed in this research are also of value to other countries and regions that are faced with the task of designing appropriate policy responses to redress their water and energy challenges.