Providing secure and reliable water supply service to major urban areas has become a considerable challenge in recent years on a global basis. Rapid population growth, urbanization and development needs put enormous pressure on water resource managers to satisfy the ever-growing demand. Climate change, in addition to the inherent variability in hydrological cycles, adds another layer of deep uncertainty to forecast surface water availability. Many major cities have observed declining reservoir storages during unprecedented droughts. The once-reliable reservoir storage systems can no longer serve its purpose. During extended period of water shortages, urban residents and businesses suffered from mandatory water restrictions, causing large economic and social welfare losses. Facing these challenges, water utilities and governments make large investments in supply augmentation infrastructure, which have long-term consequences that can shape development for decades. However, the increasing complexity of uncertainty suggests that the ability to predict the future is limited; hence, there is a need to shift from the conventional “predict-then-act” planning paradigm. This thesis presents an alternative framework to urban water investment planning, using a portfolio approach. A generalized risk-based framework for urban water supply-demand planning is proposed, and it is applied to Melbourne, Australia, to demonstrate its utility and usefulness. First of all, water shortage risk is clearly defined in two terms–frequency and severity of water shortages–of a defined planning horizon. Supply-side uncertainty is quantified based on probability distributions of precipitation and runoff to reservoirs. Demand-side uncertainty is modeled by scenarios with different combinations of population growth rate and per capita water usage. Next, the thesis presents an investment decision-making tool to identify cost-effective supply-demand portfolios that minimize water shortage severity while achieving a target level of reliable service. In addition to find the optimal portfolio composition, the model presents sequences of investments, indicating timing of implementation of each chosen measure. Using mixed integer programming, the decision-making tool yields Pareto efficient frontiers for different demand scenarios. The Pareto frontier exhibits trade-offs between cost of a water supply-demand strategy and water shortage risks facing a society in the long run. The trade-offs provide analytical insights on risk attitude towards water supply services, namely (i) what is the acceptable level of water shortage risk for a society, and (ii) how much are customers willing to pay to avoid such a risk. The results indicate that a portfolio which diversity risk of individual supply augmentation and conservation measures is robust when confronting a wide range of plausible climate and demand growth scenarios. Finally, recognizing important roles played by society and government in water-related investment decision-making process, the thesis discusses institutional barriers in adopting and implementing the proposed risk-based framework in practice. This thesis presents an alternative framework to quantitatively integrate risk in urban water resources management. Under this framework, the portfolio approach is an analytical tool for decision-makers to prioritize investments in supply augmentation infrastructure and implementation of demand management programs. It is the hope of the author that this work provides new insights and necessary tools to water sector professionals in urban water investment planning. The use of risk-based framework and portfolio approach is not limited to any specific city and could find many applications in urban areas where water scarcity and climate risk are pressing issues. / Engineering and Applied Sciences - Engineering Sciences

This study investigates the long-term thermal performance of polyurethane insulated cold storage panels and the environmental and economic impact of recycling such panels when taken out of service in lieu of discarding them in landfills. It is estimated, as of 2015, over 180 million square feet of insulated cold storage panels are manufactured annually in the U.S. The panels are most frequently constructed of closed-cell, low density polyurethane insulation utilizing HCF 245fa and HCF 134a blowing agents containing up to 6 million metric tons (CO2e) of greenhouse gases. The expected operating lifetime of the cold storage panels is 15 years after which time they are primarily discarded in landfills. This practice contributes to the build-up of greenhouse gases in the atmosphere, destroys valuable insulating and building materials and requires landfill space for the solid waste. Three recycling strategies were investigated as ways to repurpose the discarded framed cold storage panels into new forms of polyurethane insulating materials; repurposed cold storage panels, board stock insulation sheets and blown-in/fill insulation. I used three research methods to quantify the environmental and economic impacts. The first examined the initial and long-term thermal performance of the recycled polyurethane insulation through laboratory testing and extrapolative modeling. The second method was comparative life cycle assessments between the business-as-usual-case of discarding the polyurethane insulation with each of the recycled strategies. Finally, an economic analysis was completed for each recycling strategy to determine the in-use heating & cooling energy savings from the extended life of the recycled insulation. This research shows recycling of discarded polyurethane cold storage panels provide measurable environmental and economic benefit. First, the productive life of the insulation is extended greatly beyond its initial use period reducing the need for fossil fuels and raw materials to make replacement insulations. Secondly, the high insulating value of the recycled polyurethane maximizes future environmental and economic savings from lower fuel demand in space heating and cooling applications. Thirdly, the majority of the sequestered greenhouse gases continue to be bound in the foam; protecting the environment from the release of global warming gases. Finally, by diverting the cold storage panels from landfills, millions of cubic feet of landfill space are unneeded annually.

<p> Environmental sustainability requires resource management that takes future generations into account. The present generation has witnessed changes across the planet, unprecedented in human history and disrupting communities and cities around the world, due to shifting global climate. This is primarily the result of fossil fuels, which powered modern civilization but dramatically increased levels of CO₂ and other greenhouse gases, and may be the least sustainable aspect of human civilization. Chapter 1 justifies the research from an environmental perspective and provides initial research parameters. Thin film photovoltaic (PV) modules are reported the most sustainable among energy production technologies currently available. Electrodeposited PV layers offer significant improvement to sustainability metrics over current thin film production methods, at reduced cost, but have rarely been demonstrated on an industrial scale. </p><p> Quasi-rest potential (QRP) ultimately led to large-scale, electrodeposited thin film CdTe modules. An in-situ material characterization technique that allows adjustment of the deposition voltage (V_dep) to match the exact experimental conditions, QRP enabled precise control of deposit stoichiometry and crystallinity. Chapter 2 discusses theory and literature regarding QRP, and introduces the open-circuit voltage transient (V_ocT), developed by the present research for analyzing QRP as a function of both V_dep and time. V_ocT data from a CdTe ethylene glycol bath matches details and speculations from the literature. </p><p> Although predicted to have wide applicability, experimental QRP data have never been published for compounds unrelated to CdTe. Chapter 3 discusses V_ocTs performed in pursuit of electrodeposited CuInS₂, demonstrating functionality as a QRP scan in a variety of ethylene glycol solutions. Stoichiometries of deposited films were improved by using the V_ocT to determine appropriate plating voltages. V_ocTs enabled QRP, in-situ rest potential (E_M2), and current simultaneously vs V_dep and correlated with cyclic voltammetry experiments. Films approaching stoichiometric CuInS₂ were generally obtained around -1 V vs Ag/AgCl, just noble of onset of metallic indium deposition, with a QRP around -0.8 V and E_M2 between -0.55 V and -0.6 V. Sulfur content of deposited films could also be significantly increased during deposition using open-circuit techniques based on V_ocT data. Serendipitous production of large copper sulfide nanowires is briefly discussed.</p><p>

Methane, one of the primary greenhouse gases, negatively affects climate change. Its atmospheric concentration has increased dramatically over the last century and is expected to continue rising due to human activities. Oxidation of methane by methanotrophic bacteria provides a sink for methane. The rate at which methane is biologically oxidized depends on different parameters. This study aims to better understand methane oxidation in landfill cover soils. This was done through laboratory batch reactor experiments, under two levels of moisture content, two soil layer thicknesses and with and without nutrient additions. Adding nutrients to the 200 mm layer of landfill cover soil that contained 30% moisture content (by weight), increased the CH4 oxidation efficiency from 38% to 81% and the CH4 substrate utilization from 2750 mumoles/L to 5540 mumoles/L. The kinetic constants were studied in the landfill cover soil. The maximum CH4 utilization rate for different experimental runs and under different levels of the three specified parameters were between 31 and 699 mumoles/dayxkg of dry soil weight. A statistical design model was developed to describe the expected methane oxidation efficiencies under different levels of moisture content and nutrient addition that can occur in a typical landfill cover soil.

Ships produce a large amount of oily wastewaters such as bilge water which needs to be treated prior to being discharged. Bilge water is a very challenging wastewater to treat due to large variations in production rates and the complex nature of the wastes in solution. Ever increasing regulations are being imposed on the treatment and release of bilge water to the environment. The objective of this study was to develop a membrane process to remove oil and grease from bilge water to a level where it could be discharged into sensitive environments. This work focused on five elements of study: (1) Evaluation of feasibility and performance of bilge water treatment using a pilot scale microfiltration/ultrafiltration (MF/UF) hybrid membrane system; (2) Development of a pilot scale membrane cascade for selective removal of oil to 0 ppm or a non-detectable level from bilge water while minimizing concentrate production; (3) Establishment of an analytical method to extract and analyze organic species at very low concentration levels for the analysis of oil and grease content found in bilge water and membrane permeate; (4) Investigation of environmentally friendly membrane cleaning methods; and (5) Study of filtration mechanism in the treatment of bilge water using ultrafiltration and microfiltration. Pilot scale membrane cascade systems were designed and tested for the treatment of synthetic bilge water. Experimental results showed that the pretreatment of this oily wastewater using microfiltration, prior to ultrafiltration, is desirable as used oils and particulates can block the feed channels of UF spiral and hollow fiber modules. Backflushing is an effective technique to reduce fouling caused by "sticky" cakes in synthetic bilge water treatment using a microfiltration membrane. Membrane support structure was found to be critical in enhancing flux during backflushing. This work outlined the need for microfiltration membranes offering good particulate clearance to be used in backflushing coalescence applications. A pilot scale membrane hybrid system, consisting of a coalescing backflushed microfiltration membrane used as a pretreatment and an ultrafiltration membrane as a final polishing step, was found to be very effective in this application, producing permeate with oil and grease content well below the allowable discharge limit (15 ppm) for coastal waters. Another membrane cascade system using tubular MF and UF membranes in a first stage and flat sheet UF membranes in a second stage was found to be able to produce water containing below detectable levels of hexane extractable material. Permeates of various molecular weight cut-off (MWCO) membranes from the cascade system were collected and analyzed using an extraction procedure followed by gas chromatography (GC). Analytical results showed that solid phase extraction using ENVI-18 sorbent retained much of the organic matter found in the bilge water and could not preserve the molecular weight distribution in the oil mixture used to prepare synthetic bilge water. n-Hexane liquid-liquid extraction technique was found to be able to preserve the molecular weight distribution of diesel and lubricating oils separated by ultrafiltration. The effect of membrane MWCO in separation of oil and grease was also studied in this work. Environmentally friendly physical membrane cleaning methods, such as backflushing with hot water or steam followed by pressurized air, were found effective in regenerating membrane flux for large pore KOCH carbon membranes in the treatment of synthetic bilge water using a MF/UF hybrid system. The beneficial effects for steam cleaning were found to be evident. Optimal cycle times between physical cleanings were determined. Filtration mechanisms in the treatment of synthetic bilge water were studied using four classical filtration models and a combined model. Experimental results of the research conducted in this study suggested that it is possible to achieve the target of removing oil from bilge water to 0 ppm or non-detectable levels through the proper design of the membrane system, selection of appropriate membranes, determination of optimal operating parameters, and assessment of membrane performance.

<p> Requirements engineers who try to design sustainable systems may have to compromise when it comes to different environmental impacts. For example, compact fluorescent lamps contain mercury, a dangerous material. But these lamps also save energy. They reduce consumption at the expense of introducing toxic substances into the environment. To deal with these trade-offs, researchers have developed weighting metrics to account for every type of impact in a single assessment. However, the weights have the potential to direct the system design toward neglecting lowly weighted environmental concerns. </p><p> This study aims to clarify the effects of different weighting configurations. The project employs a mixing triangle that weights three different areas of environmental impact against each other. It then compares the effects of an application service provider to the effects of a system that uses locally hosted software. The comparison uses multiple weighting configurations.</p>

The Turbulent Eddy Profiler (TEP) developed at the University of Massachusetts Microwave Remote Sensing Laboratory (MIRSL) provides three dimensional fine-scale imagery of the intensity of clear-air backscatter and motion of the air with 30 meter resolution between 200 m and 2.0 km altitude. This dissertation presents the design and operation of the updated TEP system deployed in Leon, Kansas during CASES'99 experiment. Both Doppler Beam Swinging (DBS) techniques and Spaced Antenna (SA) techniques for estimating horizontal winds were applied to TEP data collected during CASES'99 experiment. This dissertation compares the results from both techniques with the simultaneous in situ Tethered Lifting System (TLS) data. Good agreement between both methods is observed at intermediate altitudes, however, DBS appears to be preferable to SA at higher altitudes where SNR is low; while SA appears to perform better at the low altitudes, where ground clutter competes with the clear-air echo.

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