28,263 research outputs found

    Municipal wastewater treatment with pond technology : historical review and future outlook

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    Facing an unprecedented population growth, it is difficult to overstress the assets for wastewater treatment of waste stabilization ponds (WSPs), i.e. high removal efficiency, simplicity, and low cost, which have been recognized by numerous scientists and operators. However, stricter discharge standards, changes in wastewater compounds, high emissions of greenhouse gases, and elevated land prices have led to their replacements in many places. This review aims at delivering a comprehensive overview of the historical development and current state of WSPs, and providing further insights to deal with their limitations in the future. The 21st century is witnessing changes in the way of approaching conventional problems in pond technology, in which WSPs should no longer be considered as a low treatment technology. Advanced models and technologies have been integrated for better design, control, and management. The roles of algae, which have been crucial as solar-powered aeration, will continue being a key solution. Yet, the separation of suspended algae to avoid deterioration of the effluent remains a major challenge in WSPs while in the case of high algal rate pond, further research is needed to maximize algal growth yield, select proper strains, and optimize harvesting methods to put algal biomass production in practice. Significant gaps need to be filled in understanding mechanisms of greenhouse gas emission, climate change mitigation, pond ecosystem services, and the fate and toxicity of emerging contaminants. From these insights, adaptation strategies are developed to deal with new opportunities and future challenges

    A Process to Implement an Artificial Neural Network and Association Rules Techniques to Improve Asset Performance and Energy Efficiency

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    In this paper, we address the problem of asset performance monitoring, with the intention of both detecting any potential reliability problem and predicting any loss of energy consumption e ciency. This is an important concern for many industries and utilities with very intensive capitalization in very long-lasting assets. To overcome this problem, in this paper we propose an approach to combine an Artificial Neural Network (ANN) with Data Mining (DM) tools, specifically with Association Rule (AR) Mining. The combination of these two techniques can now be done using software which can handle large volumes of data (big data), but the process still needs to ensure that the required amount of data will be available during the assets’ life cycle and that its quality is acceptable. The combination of these two techniques in the proposed sequence di ers from previous works found in the literature, giving researchers new options to face the problem. Practical implementation of the proposed approach may lead to novel predictive maintenance models (emerging predictive analytics) that may detect with unprecedented precision any asset’s lack of performance and help manage assets’ O&M accordingly. The approach is illustrated using specific examples where asset performance monitoring is rather complex under normal operational conditions.Ministerio de Economía y Competitividad DPI2015-70842-

    Short-term Self-Scheduling of Virtual Energy Hub Plant within Thermal Energy Market

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    Multicarrier energy systems create new challenges as well as opportunities in future energy systems. One of these challenges is the interaction among multiple energy systems and energy hubs in different energy markets. By the advent of the local thermal energy market in many countries, energy hubs' scheduling becomes more prominent. In this article, a new approach to energy hubs' scheduling is offered, called virtual energy hub (VEH). The proposed concept of the energy hub, which is named as the VEH in this article, is referred to as an architecture based on the energy hub concept beside the proposed self-scheduling approach. The VEH is operated based on the different energy carriers and facilities as well as maximizes its revenue by participating in the various local energy markets. The proposed VEH optimizes its revenue from participating in the electrical and thermal energy markets and by examining both local markets. Participation of a player in the energy markets by using the integrated point of view can be reached to a higher benefit and optimal operation of the facilities in comparison with independent energy systems. In a competitive energy market, a VEH optimizes its self-scheduling problem in order to maximize its benefit considering uncertainties related to renewable resources. To handle the problem under uncertainty, a nonprobabilistic information gap method is implemented in this study. The proposed model enables the VEH to pursue two different strategies concerning uncertainties, namely risk-averse strategy and risk-seeker strategy. For effective participation of the renewable-based VEH plant in the local energy market, a compressed air energy storage unit is used as a solution for the volatility of the wind power generation. Finally, the proposed model is applied to a test case, and the numerical results validate the proposed approach

    The 2008 WITCH Model: New Model Features and Baseline

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    WITCH is an energy-economy-climate model developed by the climate change group at FEEM. The model has been extensively used in the past 3 years for the economic analysis of climate change policies. WITCH is a hybrid top-down economic model with a representation of the energy sector of medium complexity. Two distinguishing features of the WITCH model are the representation of endogenous technological change and the game–theoretic set-up. Technological change is driven by innovation and diffusion processes, both of which feature international spillovers. World countries are grouped in 12 regions which interact with each other in a setting of strategic interdependence. This paper describes the updating of the base year data to 2005 and some new features: the inclusion of non-CO2 greenhouse gases and abatement options, the new specification of low carbon technologies and the inclusion of reducing emissions from deforestation and degradation.Climate Policy, Hybrid Modelling, Integrated Assessment, Technological Change

    The Extension of the RAINS Model to Greenhouse Gases

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    Many of the traditional air pollutants and greenhouse gases have common sources, offering a cost-effective potential for simultaneous improvements for both traditional air pollution problems as well as climate change. A methodology has been developed to extend the RAINS integrated assessment model to explore synergies and trade-offs between the control of greenhouse gases and air pollution. With this extension, the RAINS model allows now the assessment of emission control costs for the six greenhouse gases covered under the Kyoto Protocol (CO2, CH4, N2O and the three F-gases) together with the emissions of air pollutants SO2, NOX, VOC, NH3 AND PM. In the first phase of the study, emissions, costs and control potentials for the six greenhouse gases covered in the Kyoto Protocol have been estimated and implemented in the RAINS model. Emission estimates are based on methodologies and emission factors proposed by the IPCC emission reporting guidelines. The large number of control options for greenhouse gases have been grouped into approximately 150 packages of measures and implemented in the RAINS model for the European countries. These control options span a wide range of cost-effectiveness. There a re certain advanced technical measures with moderate costs, and certain measures exist for which the economic assessment suggests even negative costs, if major side impacts (cost savings) are calculated. Illustrative example calculations clearly demonstrate that conclusions on the cost-effectiveness of emission reduction strategies are crucially depending on the boundaries of the analysis. The net cost of greenhouse gas control strategies are significantly lower if the immediate cost-savings from avoided air pollution control costs are taken into consideration. For a 15 percent reduction of the CO2 emissions from the power sector in the EU, avoided pollution control costs could compensate two third of the CO2 control costs. Depending on the design of the control strategy, net costs of greenhouse gas mitigation could even be negative, which is in stark contrast to conclusions for a CO2 only strategy. However, there are certain greenhouse gas mitigation measures, such as increased use of biomass that could deteriorate the negative impacts of air pollution, while yielding very little economic synergies. A combined approach towards greenhouse gas mitigation and air pollution control would not only reveal economic synergies, but also harness additional environmental benefits. Even in a situation with stringent emission control requirements for air pollution as it is required by the EU legislation, modifications in fuel use geared towards reductions of greenhouse gases could lead as a side impact to significant reductions in the residual emissions of air pollutants. The economic benefits of such "windfall emission reductions" could be substantial. The extended RAINS model framework will offer a tool to systematically investigate such economic and environmental synergies between greenhouse gas mitigation and air pollution control while avoiding negative side impacts

    Greenhouse engineering: New technologies and approaches

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    Firstly, this article discusses the greenhouse engineering situation in three geographic areas which are relevant in the field of protected cultivation: Northern Asia, The Netherlands and the Mediterranean. For each area, the prevailing greenhouse type and equipment is briefly described. Secondly, the main technological constraints are pointed out and finally the research directions are discussed. For all areas under consideration, attempts to design more efficient greenhouse systems are under way. In Northern Asia progress is being made towards the optimisation of greenhouses as a solar collector and to the development of new heating strategies. Important subjects addressed in The Netherlands are energy conservation and the replacement or alleviation of human labour by increasing mechanisation. In the Mediterranean there is growing interest in semi-closed greenhouses with CO2 enrichment and control of excessive humidity. All geographic areas share the need of having an optimised climate control based on the crop response to the greenhouse environment. All areas also share the requirement of being respectful to the environment, therefore future greenhouses are expected to use engineering to produce with minimal or zero emissions

    Wind Energy Management

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    The book "Wind Energy Management" is a required part of pursuing research work in the field of Renewable Energy at most universities. It provides in-depth knowledge to the subject for the beginners and stimulates further interest in the topic. The salient features of this book include: - Strong coverage of key topics - User friendly and accessible presentation to make learning interesting as much as possible - Its approach is explanatory and language is lucid and communicable - Recent research papers are incorporate
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