1,103 research outputs found

    Sustainability Informed Management of End-of-Life Photovoltaics: Assessing Environmental and Economic Tradeoffs of Collection and Recycling

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    Renewable energy technologies have emerged to address the negative environmental impacts of increasing use of fossil fuels. Solar photovoltaics (PV) are an attractive renewable energy technology because they avoid significant carbon emissions during use common to non-renewables, have a long useful lifetime estimated at 20 - 30 years, and they take advantage of a stable and plentiful energy resource - the sun. However, it has been suggested that material availability is a potential constraint for broad deployment of PV. For example, solar PV\u27s core technology depends on several primary materials i.e. indum and tellurium which were recently determined to be of high importance for the development of a clean energy economy and at near-critical supply risk. In order to evaluate the risks to supply, the environment, and the economy a broader definition of criticality that goes beyond physical scarcity to include sustainability metrics e.g. embodied energy, political instability, economic value was developed. Using this methodology several policies are suggested that depart from traditional command- and-control approaches. One criticality mitigating strategy, material recycling, is at odds with current PV research where there is a strong emphasis on efficiency gains. Recycling is a strategy with potential that has yet to be fully recognized due to the current lack of collection infrastructure and uncertain set of processing technologies. This work explores under what conditions the energy payback time (EPBT) of PV modules containing recycled materials demonstrate equivalent energy savings to improvements in efficiency. These EPBT improvements from recycling motivate further methodological work on the economically optimal PV recycling infrastructure. This methodology includes a case study that demonstrates model sensitivity in addition to revealing important tradeoffs for recycling policy and economics

    Food Waste Management Networks: Novel Methods for Overcoming Emerging Logistics Challenges

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    The U.S. produces an estimated 63 million tons of food waste per year. Interest from state and local governments in diverting unused food from landfills to alternative treatment facilities is growing. However, this emerging food waste (FW) stream will face logistics challenges as diversion networks expand. Current methods for evaluating challenges are insufficient for providing solutions for network development because they do not explore the impacts of variability in the food waste management system. This dissertation aims to fill this knowledge gap by exploring three key research areas. First, variability in FW generation from different types of commercial generators is characterized. Empirically collected data is combined with the prevailing FW estimation method to characterize how generator attributes, temporal variability, and spatial heterogeneity in FW generation could impact development of diversion networks. Results show that representing FW generation from commercial sources in New York State with a single annual value is likely inadequate for policy and planning purposes due to the uncertainty surrounding anticipated FW generation. Second, two transportation models are presented to understand how variability in spatial locations and generation rates affects FW collection. Results indicate that in residential systems with uniform generation rates, increasing spatial density of participants is critical to reducing service costs. In commercial systems, the inherent heterogeneity of food waste generation rates is important to reduce costs for initial collection services. Finally, material inputs and digestate management are incorporated into a FW treatment facility siting method. Results show that digestate transportation distance is critical for ensuring that land application of digestate does not overload nearby farm fields with phosphorus. This dissertation contributes to the body of scientific knowledge for waste management through the creation of novel, generalizable methods that investigate the impacts of variability on logistics decisions to inform development of effective food waste management networks

    Municipal solid waste management system: decision support through systems analysis

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    Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia for the degree of Doctor of Philosophy in Environmental EngineeringThe present study intends to show the development of systems analysis model applied to solid waste management system, applied into AMARSUL, a solid waste management system responsible for the management of municipal solid waste produced in Setúbal peninsula, Portugal. The model developed intended to promote sustainable decision making, covering the four columns: technical, environmental, economic and social aspects. To develop the model an intensive literature review have been conducted. To simplify the discussion, the spectrum of these systems engineering models and system assessment tools was divided into two broadly-based domains associated with fourteen categories although some of them may be intertwined with each other. The first domain comprises systems engineering models including cost-benefit analysis, forecasting analysis, simulation analysis, optimization analysis, and integrated modeling system whereas the second domain introduces system assessment tools including management information systems, scenario development, material flow analysis, life cycle assessment (LCA), risk assessment, environmental impact assessment, strategic environmental assessment, socio-economic assessment, and sustainable assessment. The literature performed have indicated that sustainable assessment models have been one of the most applied into solid waste management, being methods like LCA and optimization modeling (including multicriteria decision making(MCDM)) also important systems analysis methods. These were the methods (LCA and MCDM) applied to compose the system analysis model for solid waste. The life cycle assessment have been conducted based on ISO 14040 family of norms; for multicriteria decision making there is no procedure neither guidelines, being applied analytic hierarchy process (AHP) based Fuzzy Interval technique for order performance by similarity to ideal solution (TOPSIS). Multicriteria decision making have included several data from life cycle assessment to construct environmental, social and technical attributes, plus economic criteria obtained from collected data from stakeholders involved in the study. The results have shown that solutions including anaerobic digestion in mechanical biological treatment plant plus anaerobic digestion of biodegradable municipal waste from source separation, with energetic recovery of refuse derived fuel (RDF) and promoting pays-as-you-throw instrument to promote recycling targets compliance would be the best solutions to implement in AMARSUL system. The direct burning of high calorific fraction instead of RDF has not been advantageous considering all criteria, however, during LCA, the results were the reversal. Also it refers that aerobic mechanical biological treatment should be closed.Fundação para a Ciência e Tecnologia - SFRH/BD/27402/200

    OR models in urban service facility location : a critical review of applications and future developments

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    [EN] Facility location models are well established in various application areas with more than a century of history in academia. Since the 1970s the trend has been shifting from manufacturing to service industries. Due to their nature, service industries are frequently located in or near urban areas that results in additional assumptions, objectives and constraints other than those in more traditional manufacturing location models. This survey focuses on the location of service facilities in urban areas. We studied 110 research papers across different journals and disciplines. We have analyzed these papers on two levels. On the first, we take an Operations Research perspective to investigate the papers in terms of types of decisions, location space, main assumptions, input parameters, objective functions and constraints. On the second level, we compare and contrast the papers in each of these applications categories: (a) Waste management systems (WMS), (b) Large-scale disaster (LSD), (c) Small-scale emergency (SSE), (d) General service and infrastructure (GSI), (e) Non-emergency healthcare systems (NEH) and (f) Transportation systems and their infrastructure (TSI). Each of these categories is critically analyzed in terms of application, assumptions, decision variables, input parameters, constraints, objective functions and solution techniques. Gaps, research opportunities and trends are identified within each category. Finally, some general lessons learned based on the practicality of the models is synthesized to suggest avenues of future research.Ruben Ruiz is partially supported by the Spanish Ministry of Economy and Competitiveness, under the project "SCHEYARD - Optimization of Scheduling Problems in Container Yards (No. DPI2015-65895-R) financed by FEDER funds.Farahani, RZ.; Fallah, S.; Ruiz García, R.; Hosseini, S.; Asgari, N. (2019). OR Models in Urban Service Facility Location: A Critical Review of Applications and Future Developments. European Journal of Operational Research. 276(1):1-27. https://doi.org/10.1016/j.ejor.2018.07.036S127276

    Building with Waste: A Creative Diversion Towards Managing Wood Pallet Waste in Hawai'i

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    Arch.D.Arch.D. Thesis. University of Hawaiʻi at Mānoa 201

    A DECISION-BASED DESIGN PROCESS FOR ECO-INDUSTRIAL PARKS

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    This thesis presents a new process for designing eco-industrial parks (i.e., EIPs) that identifies the decisions that need to be made during each phase. A literature review about the different EIP development processes in the U.S. and worldwide is conducted to create a general EIP development process. A careful analysis of 21 EIP development processes was conducted to illuminate the different routines associated with each step in these processes. This thesis presents a revised EIP development process that follows the decision-based design principle of aligning all decisions with the involved organizations' most important objectives

    SYSTEMS ANALYSIS FOR SUSTAINABILITY ASSESSMENT OF BIOGAS AND BIO-CH4 PRODUCTION FROM FOOD WASTE AND DAIRY MANURE MIXTURES IN THE US

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    The purpose of the dissertation is to relate systems analysis for bioenergy to identify optimum configurations for improved scenarios and to make better decisions in a systems perspective. Chapter 1 is a review of the literature to identify the state of the knowledge in terms of systems analysis for anaerobic digestion (AD) bioenergy systems. The key outcomes from this review showed that anaerobic digestion of mixtures of food waste and animal manure has great potential to achieve economic and environmental benefits compared to other treatments of organic waste materials, such as landfilling or conventional manure management. Chapter 2 focuses on carbon footprint of one particular bio-CH4 production facility. This study developed consequential methodology to address the environmental impacts of system parameters such as avoiding landfilling and manure management. The key results from this LCA show that the AD Bio-CH4 pathway has 15.5% lower greenhouse gas (GHG) emissions compared to the prior practice of composting of food waste and manure in Denver, CO. Then chapter 3 provides opportunities for additional studies in bioenergy environmental and economic performance. The objective of this chapter is to gain a system level understanding of the integration of bioenergy crops into rotations with food grains. This study combines both environmental and economic impacts into a single decision assessment. The key results in this chapter show the system parameter yield is the deciding parameter in finding the most optimum crop rotations with integration of bioenergy crops. In Chapter 4 the objective is to understand enzyme accessibility inside woody biomass and its role in controlling the rate of conversion of cellulose to glucose. The goal of this study was to measure the cellulose accessibility due to the effect of dilute acid pretreatment (DAP) and enzymatic hydrolysis (EH) time of Populus biomass. The last chapter of the dissertation presents a novel systems sustainability analysis framework that evaluates the optimum locations, sizes, and the number of plants for AD biogas power production in Wisconsin accounting for both the profits from the biopower supply chain and carbon credits. This dissertation ends with overall conclusions and recommendations for future research

    Industry 4.0 remanufacturing: a novel approach towards smart remanufacturing

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    “Smart remanufacturing has become more popular in recent years as a result of its multiple benefits and the growing need for society to encourage a circular economy that leads to sustainability. One of the most common end-of-life (EoL) choices that can lead to a circular economy is remanufacturing. As a result, at the end-of-life stage of a product, it is critical to prioritize this choice over other accessible options because it is the only recovery option that retains the same quality as a new product. This work focuses on the numerous technologies that can aid in the improvement of smart remanufacturing; in other words, the various technologies that can be utilized to simplify the process of smart remanufacturing, enhance quality, and increase customer trust. A modern approach towards smart remanufacturing has been discussed in this paper, with an aim to fill the gaps in the current remanufacturing process. 67 research papers from three databases are used for this review : Science Direct, Web of Science, and Scopus”--Abstract, page iii
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