5,977 research outputs found

    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

    Economic Model for Household Solid Waste Collection

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    Protection of public health and water resources is partly maintained through efficient waste collection. This paper presents a model to calculate collection and transfer cost of household solid waste. The model was applied to estimate the collection and transfer cost of household waste for a district in Cairo, Egypt. The model was calibrated and verified using data that was collected through surveying 30 waste collectors. The model is applied for both new and used trucks and was successful in determining the required fee to be collected per household and per ton of waste. The collection and transfer cost model is based on variable and fixed costs. Collection and transfer costs, in Egypt, were less than those presented in literature. This was attributed to lower labour cost and lower capital costs needed for waste collection and transfer. Keywords: Municipal solid waste management system; Collection and transfer cost; Household Waste, Waste collection mode

    A life cycle optimization framework for the sustainable design of circular municipal solid waste management systems

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    RESUMEN: Los objetivos de esta tesis son desarrollar un marco metodológico para determinar la configuración óptima de los sistemas integrados de gestión de residuos bajo una perspectiva del ciclo de vida, e investigar si la economía circular contribuye a la reducción del consumo de recursos y los impactos ambientales y al crecimiento económico. El marco metodológico propuesto se aplicó a la gestión de residuos municipales orgánicos en la Comunidad Autónoma de Cantabria. El modelo del sistema se construyó combinando análisis de flujo de materiales y análisis de ciclo de vida (ambiental y económico). Se formuló un problema de optimización multi-objetivo para maximizar la circularidad de los nutrientes y minimizar el uso de recursos, los impactos ambientales y los costes de gestión de residuos. Los resultados sugieren que mejorar la circularidad de los recursos no implica necesariamente una reducción de costes, del consumo de recursos o de la emisión de cargas ambientales.ABSTRACT: The objectives of this dissertation are twofold: to develop a methodological framework to select the optimal configuration of integrated waste management systems under a life cycle perspective, and to investigate whether adopting a circular economy is an effective measure to attain increased economic benefits and a reduction in resource consumption and environmental impacts. The proposed framework – based the expansion of the boundaries of linear waste management systems – was applied to the management of municipal organic waste in the Spanish region of Cantabria. The system model was constructed combining material flow analysis, life cycle assessment and life cycle costing tools. A multi-objective optimization problem was formulated to maximize nutrient circularity and minimize resource use, environmental impacts and waste management costs. The results suggest that improving resource circularity can lead to increased costs and does not necessarily entail a decrease in the consumption of natural resources or the emission of environmental burdens.The author has been the recipient of two predoctoral fellowships granted by the University of Cantabria and the Spanish Ministry of Education (code FPU 15/01771). Her visit to NCSU was funded by a predoctoral mobility scholarship awarded by the University of Cantabria and by the research project CTQ2016-76231-C2-1-R, whereas her research at Cornell University was sponsored by the FPU program (code EST18/00007). She gratefully acknowledges this financial support

    Barriers to circular food supply chains in China

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    Purpose: This paper aims to identify and systematically analyze the causal-effect relationships among barriers to circular food supply chains in China. Design/methodology/approach: Grounded in multiple organizational theories, this paper develops a theoretical framework for identifying relevant barriers to integrating circular economy philosophy in food supply chain management. The study uses 105 responses from Chinese food supply chain stakeholders including food processors, sales and distribution channels, consumers and government officials. It applies a fuzzy decision-making trial and evaluation laboratory (DEMATEL) method to examine the causal-effect relationships among the identified barriers. Findings: Overall, the results suggest two key cause barriers: first, weak environmental regulations and enforcement, and second, lack of market preference/pressure. Meanwhile, lack of collaboration/support from supply chain actors is the most prominent barrier. The key cause and prominent barriers are also identified for each of the supply chain stakeholder involved. Research implications: The study offers practical insights for overcoming barriers to integrating circular economy philosophy in the management of supply chains in the Chinese food sector, as well as in other contexts where similar challenges are faced. It also sheds light on which organizational theories are most suitable for guiding similar studies. Originality/value: To the best of the authors’ knowledge, this is the first barrier study on circular food supply chains. The use of multiple organizational theories for the development of the theoretical framework is unique in barrier studies. The study offers insights from multiple stakeholders in the Chinese food supply chains

    Sustainability as a Multi-criteria Concept

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    Sustainability is a fairly old concept, born in the 18th century in the field of forestry, within a mono-functionality perspective. The concept has considerably evolved in the last few years towards a multi-functionality context, with applications reported in practically all areas of economic interest. On the other hand, modern sustainability is a complex problem, for two reasons: a) The multiplicity of functions of a very different nature involved in the process and b) The manner in which different segments of the society or stakeholders perceive the relative importance of these functions. For the above reasons, a realistic approach for dealing with the sustainability issue requires taking into consideration multiple criteria of different nature (economic, environmental and social), and in many cases within a participatory decision making framework. This book presents a collection of papers, dealing with different theoretical and applied issues of sustainability, with the help of a modern multi-criteria decision-making theory, with a single as well as several stakeholders involved in the decision-making process. Hopefully, this material will encourage academics and practitioners to alter their research in this hot and vital topic. After all, the sustainable management of the environment and its embedded resources is one of the most important, if not the major challenge of the 21st century

    Analysis of Voluntary Commitments Targeting Marine Litter and Microplastics Pursuant to Resolution 3/7

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    The present report is being submitted pursuant to paragraph 9 of resolution 3/71 of the United Nations Environment Assembly of the United Nations Environment Programme (UNEP), in which the Environment Assembly requested the Executive Director of UNEP to compile voluntary commitments, as applicable, targeting marine litter and microplastics; to provide an overview of their scope in support of the work of the Environment Assembly on that issue; to better understand progress towards achieving Sustainable Development Goal target 14.1 on preventing andsignificantly reducing marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution, by 2025 (see General Assembly resolution 71/313); and to report to the Environment Assembly at its fourth session on the matter.The report contains an analysis of the voluntary commitments made in the context of the United Nations Conference to Support the Implementation of Sustainable Development Goal 14, the Our Ocean Conference, the United Nations Sustainable Development Platform, the Clean Seas campaign and the Environment Assembly portal for voluntary reporting relating to marine litter

    Landfill Gas To Energy Incentives And Benefits

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    Municipal solid waste (MSW) management strategies typically include a combination of three approaches, recycling, combustion, and landfill disposal. In the US approximately 54% of the generated MSW was landfilled in 2008, mainly because of its simplicity and cost-effectiveness. However, landfills remain a major concern due to potential landfill gas (LFG) emissions, generated from the chemical and biological processes occurring in the disposed waste. The main components of LFG are methane (50-60%) and carbon dioxide (40-50%). Although LFG poses a threat to the environment, if managed properly it is a valuable energy resource due to the methane content. Currently there are over 550 active LFG to energy (LFGTE) facilities in the US, producing renewable energy from LFG. A major challenge in designing/operating a LFGTE facility is the uncertainty in LFG generation rate predictions. LFG generation rates are currently estimated using models that are dependent upon the waste disposal history, moisture content, cover type, and gas collection system, which are associated with significant uncertainties. The objectives of this research were to: Evaluate various approaches of estimating LFG generation and to quantify the uncertainty of the model outcomes based on case-study analysis, Present a methodology to predict long-term LFGTE potential under various operating practices on a regional scale, and Investigate costs and benefits of emitting vs. collecting LFG emissions with regards to operation strategies and regulations. iii The first-order empirical model appeared to be insensitive to the approach taken in quantifying the model parameters, suggesting that the model may be inadequate to accurately describe LFG generation and collection. The uncertainty values for the model were, in general, at their lowest within five years after waste placement ended. Because of the exponential nature, the uncertainty increased as LFG generation declined to low values decades after the end of waste placement. A methodology was presented to estimate LFGTE potential on a regional scale over a 25-year timeframe with consideration of modeling uncertainties. The methodology was demonstrated for the US state of Florida, and showed that Florida could increase the annual LFGTE production by more than threefold by 2035 through installation of LFGTE facilities at all landfills. Results showed that diverting food waste could significantly reduce fugitive LFG emissions, while having minimal effect on the LFGTE potential. Estimates showed that with enhanced landfill operation and energy production practices, LFGTE power density could be comparable to technologies such as wind, tidal, and geothermal. More aggressive operations must be considered to avoid fugitive LFG emissions, which could significantly affect the economic viability of landfills. With little economic motivation for US landfill owners to voluntarily reduce fugitive emissions, regulations are necessary to increase the cost of emitting GHGs. In light of the recent economic recession, it is not likely that a carbon tax will be established; while a carbon trading program will enforce emission caps and provide a tool to offset some costs and improve emission-reduction systems. Immediate action establishing a iv US carbon trading market with carbon credit pricing and trading supervised by the federal government may be the solution. Costs of achieving high lifetime LFG collection efficiencies are unlikely to be covered with revenues from tipping fee, electricity sales, tax credits, or carbon credit trading. Under scenarios of highly regulated LFG emissions, sustainable landfilling will require research, development, and application of technologies to reduce the marginal abatement cost, including: Diverting rapidly decomposable waste to alternative treatment methods, Reducing fugitive emissions through usage daily/intermediate covers with high oxidation potential, Increasing the lifetime LFG collection efficiency, and Increasing LFG energy value – for instance by producing high-methane gas through biologically altering the LFG generation pathwa

    Sustainability assessment of biomass-based energy supply chain using multi-objective optimization model

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    In recent years, population growth and lifestyle changes have led to an increase in energy consumption worldwide. Providing energy from fossil fuels has negative consequences, such as energy supply constraints and overall greenhouse gas emissions. As the world continues to evolve, reducing dependence on fossil fuels and finding alternative energy sources becomes increasingly urgent. Renewable energy sources are the best way for all countries to reduce reliance on fossil fuels while reducing pollution. Biomass as a renewable energy source is an alternative energy source that can meet energy needs and contribute to global warming and climate change reduction. Among the many renewable energy options, biomass energy has found a wide range of application areas due to its resource diversity and easy availability from various sources all year round. The supply assurance of such energy sources is based on a sustainable and effective supply chain. Simultaneous improvement of the biomass-based supply chain's economic, environmental and social performance is a key factor for optimum network design. This study has suggested a multi-objective goal programming (MOGP) model to optimize a multi-stage biomass-based sustainable renewable energy supply chain network design. The proposed MOGP model represents decisions regarding the optimal number, locations, size of processing facilities and warehouses, and amounts of biomass and final products transported between the locations. The proposed model has been applied to a real-world case study in Istanbul. In addition, sensitivity analysis has been conducted to analyze the effects of biomass availability, processing capacity, storage capacity, electricity generation capacity, and the weight of the goals on the solutions. To realize sensitivity analysis related to the importance of goals, for the first time in the literature, this study employed a spherical fuzzy set-based analytic hierarchy method to determine the weights of goals

    Experimental investigation and modelling of the heating value and elemental composition of biomass through artificial intelligence

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    Abstract: Knowledge advancement in artificial intelligence and blockchain technologies provides new potential predictive reliability for biomass energy value chain. However, for the prediction approach against experimental methodology, the prediction accuracy is expected to be high in order to develop a high fidelity and robust software which can serve as a tool in the decision making process. The global standards related to classification methods and energetic properties of biomass are still evolving given different observation and results which have been reported in the literature. Apart from these, there is a need for a holistic understanding of the effect of particle sizes and geospatial factors on the physicochemical properties of biomass to increase the uptake of bioenergy. Therefore, this research carried out an experimental investigation of some selected bioresources and also develops high-fidelity models built on artificial intelligence capability to accurately classify the biomass feedstocks, predict the main elemental composition (Carbon, Hydrogen, and Oxygen) on dry basis and the Heating value in (MJ/kg) of biomass...Ph.D. (Mechanical Engineering Science

    Gasification for Practical Applications

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    Although there were many books and papers that deal with gasification, there has been only a few practical book explaining the technology in actual application and the market situation in reality. Gasification is a key technology in converting coal, biomass, and wastes to useful high-value products. Until renewable energy can provide affordable energy hopefully by the year 2030, gasification can bridge the transition period by providing the clean liquid fuels, gas, and chemicals from the low grade feedstock. Gasification still needs many upgrades and technology breakthroughs. It remains in the niche market, not fully competitive in the major market of electricity generation, chemicals, and liquid fuels that are supplied from relatively cheap fossil fuels. The book provides the practical information for researchers and graduate students who want to review the current situation, to upgrade, and to bring in a new idea to the conventional gasification technologies
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