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This contribution provides an overview of IoT embedded in the cities, its contributions and the challenges, from the environmental perspective. Energy, which is the essential lifeline of smart cities, can be a crucial sector benefiting from IoT implementation. However, there is still a research gap on the offset/saving versus the footprint of the IT sector. The overall reduction of energy consumptions through the integration of IoT is yet to be verified. The end of life management remains an issue. Continuous research and development, as well as assessment, could bring the sustainable smart concept into its real-life implementation in the foreseeable future. The presentation stems to provide a platform for the discussion of future research directions and priorities.

The trade-off between the degree of circularity in industrial and urban processes and the spent resources in terms of energy and funds poses a challenging task. Material and energy flows feature different global patterns, which sets them as two interacting dimensions in the process. This work proposes the Multi-Resource Integration Map concept for modelling the recycling processes and representing the trade-off. The criteria used are based on exergy expenditure and cost, evaluated against the degree of circularity represented by the newly formulated Total Circularity Index (TCI), combining the Circular Material Use rate and Circular Exergy Use rate. The method is demonstrated in a case study from the domain of urban symbiosis where a set of waste resources are available to serve, after processing, part of specified product demands. The results show that the optimal exergy consumption (690 kW, TCI = 0.396) and the optimal Total Annual Cost (102.7 kEUR/y, TCI = 0.359) take place at different but correlating Total Circularity Index values. The optima are 33% lower in terms of cost and 22% lower in terms of exergy than the point of maximum circularity. The method proposed in this paper provides guidance for the integration of multi-resource systems, allowing the decision-makers to estimate the economic and exergy performance of the proposed Circular Economy solutions, aiding in improving the sustainability contributions of industrial and urban systems.

COVID-19 has caused great challenges to the energy industry. Potential new practices and social forms being facilitated by the pandemics are having impacts on energy demand and consumption. Spatial and temporal heterogeneities of impacts appear gradually due to the dynamics of pandemics and mitigation measures. This paper overviews the impacts and challenges of COVID-19 pandemics on energy demand and consumption and highlights energy-related lessons and emerging opportunities. The discussion on energy-related issues is divided into four main sections: emergency situation and its impacts, environmental impacts and stabilising energy demand, recovering energy demand, and lessons and emerging opportunities. The changes in energy requirements are compared and analysed from multiple perspectives according to available data and information. In general, although the overall energy demand declines, the spatial and temporal variations are complicated. The energy intensity has presented apparent changes, the extra energy for COVID-19 fighting is non-negligible for stabilising energy demand, and the energy recovery in different regions presents significant differences. A crucial issue has been to allocate and find energy-related emerging opportunities for the post pandemics. This study could offer a direction in opening new avenues for increasing energy efficiency and promoting energy saving.

COVID-19 has been sweeping the world. The overall number of infected persons has been increased from 5 M in March 2020 to over 22 M in August 2020 and growing, which seems not to get its peak at the current stage. This has contributed to waste generation and different phases of challenges in waste management practices. The impacts including change in waste amount, composition, timing/frequency (temporal), distribution (spatial) and risk, which affects the handling and treatment practices. Recent impacts, challenges and developments on waste management in the response of COVID-19 have been assessed in this update. Singapore, the cities of Shanghai in China and Brno in the Czech Republic (a member state of the European Union), representing different pandemic development situation and also various cultural attitudes, are specifically analysed and discussed with current data. However, it should be noted that it is still fast developing. A varying trend in term of the waste amount is identified. Shanghai is showing a ~23% decline in household waste amount; however, Singapore is showing a ~3% increase, and Brno is showing a ~1% increase in household waste amount but ~40% decline in business and industrial waste. Manual sorting and recycling have been reported as restricted due to safety precaution. This is supported by the interview communication with ZEVO SAKO (the largest incineration plant in the Czech Republic). This study highlighted that the practices or measures at each place could serve as a guideline and reference. However, adaption is required according to the geographical and socioeconomic factors., Graphical abstract Unlabelled Image, Highlights • The influence of COVID-19 on waste management is summarised. • Manual sorting and recycling are restricted due to the potential risk of infection. • Shanghai shows a 23% reduction in MSW and 3% increase in Singapore. • Brno demonstrates 1% increase for MSW from household and small business, 40% decrease for business and industrial. • The impacts of COVID-19 can be diverse depending on the geographical and sociological factors.

The coronavirus disease 2019 (COVID-19) pandemic has magnified the insufficient readiness of humans in dealing with such an unexpected occurrence. During the pandemic, sustainable development goals have been hindered severely. Various observations and lessons have been highlighted to emphasise local impacts on a single region or single sector, whilst the holistic and coupling impacts are rarely investigated. This study overviews the structural changes and spatial heterogeneities of changes in healthcare, energy and environment, and offers perspectives for the in-depth understanding of the COVID-19 impacts on the three sectors, in particular the cross-sections of them. Practical observations are summarised through the broad overview. A novel concept of the healthcare–energy–environment nexus under climate change constraints is proposed and discussed, to illustrate the relationships amongst the three sectors and further analyse the dynamics of the attention to healthcare, energy and environment in view of decision-makers. The society is still on the way to understanding the impacts of the whole episode of COVID-19 on healthcare, energy, environment and beyond. The raised nexus thinking could contribute to understanding the complicated COVID-19 impacts and guiding sustainable future planning.

Highlights • Data mining approaches are applied to measure and improve social media publicity. • The current publicity in household waste management leans toward propagandist-centred. • The identified high user engagements are at 12:00–13:00 and 21:00–22:00 on thursday. • The macro policy in shanghai increases the recyclable waste collection by 431.8%. • A case study in shanghai presents personalised improvements in waste management., Household waste segregation and recycling is ranked at a high priority of the waste management hierarchy. Its management remains a great challenge due to the high dependency on social behaviours. The integration of Internet of Things (IoT) and subscription accounts on social media platforms related to household waste management could be an effective and environmentally friendly publicity approach than traditional publicity via posters and newspapers. However, there is a paucity of literature on measuring social media publicity in household waste management, which brings challenges for practitioners to characterise and improve this publicity pathway. In this study, under an integrated framework, data mining approaches are employed or extended for multidimensional publicity analytics using the data of online footprints of propagandist and users. A real-world case study based on a subscription account on the WeChat platform, Shanghai Green Account, is analysed to reveal useful insights for personalised improvements of household waste management. This study suggests that the current publicity related to household waste management leans towards propagandist-centred in both timing and topic dimensions. The identified timing, which has high user engagement, is 12:00–13:00 and 21:00–22:00 on Thursday. The overall relative publicity quality of historical posts is calculated as 0.95. Average user engagement under the macro policy in Shanghai was elevated by 138.5% from 2018 to 2019, during which the collections of biodegradable food waste and recyclable waste were elevated by 88.8% and 431.8%. Intelligent decision support by publicity analytics could enhance household waste management through effective communication., Graphical abstract Image, graphical abstract

The still escalating COVID-19 pandemic also has a substantial impact on energy structure, requirements and related emissions. The consumption is unavoidable and receives a lower priority in the critical situation. However, as the pandemic continues, the impacts on energy and environment should be assessed and possibly reduced. This study aims to provide an overview of invested energy sources and environmental footprints in fighting the COVID-19. The required energy and resources consumption of Personal Protection Equipment (PPE) and testing kits have been discussed. The protecting efficiency returned on environmental footprint invested for masks has been further explored. The main observation pinpointed is that with a proper design standard, material selection and user guideline, reusable PPE could be an effective option with lower energy consumption/environmental footprint. Additional escalated energy consumption for aseptic and disinfection has been assessed. This includes the energy stemming from emergency and later managed supply chains. The outcomes emphasised that diversifying solutions to achieve the needed objective is a vital strategy to improve the susceptibility and provide higher flexibility in minimising the environmental footprints. However, more comprehensive research proof for the alternative solution (e.g. reusable option) towards low energy consumption without compromise on the effectiveness should be offered and advocated., Graphical abstract Image 1, Highlights • COVID-19 pandemic impacts on energy structure, energy requirements and related emissions. • Overview of the invested energy sources and environmental footprints increased. • Required energy and resources consumption of Personal Protection Equipment (PPE) and testing kits. • An assessment of intensive energy consumption for aseptic and disinfection. • The outcomes emphasised that diversifying solutions are a vital strategy needed.

Reduction of landfills and dealing with the waste are among the key elements of the cleaner production and advanced environment policy. Composting represents one of the cleaner technologies in diverting organic waste from landfill. However, it has not been commonly practised in the developing countries due to low economic feasibility and environmental issues that arise from the abuse of compost quality. There are a lack of product standards and an indication of compost quality to govern its market and application. In order to foster public confidence in compost utilisation and as much as possible offset the operating cost, an economic assessment system is needed to benchmark the quality of the compost at a reasonable cost. In this study, a set of composting parameters and their analysis have been reviewed and ranked following their total scores in terms of relation to the agronomic value, technical complexity and analysis cost. The parameters were selected based on different assessment criteria. An assessment system developed on the base of the decision analysis comprises minimal analyses needed to assess the compost quality. The cost savings results from the presented work are illustrated by four scenarios: Scenario 1 served as the baseline to include all the necessary analyses and the remaining three (Scenarios 2, 3 and 4) had been evaluated by the developed assessment system. It is shown that the cost to assess the compost quality was reduced from 17 to 84 % depending on the type of input material and composting performance. The highest cost saving based on the analysis of compost quality reaching 84 % was achieved by Scenario 4 where composting was carried out using the segregated food and landscape waste. The assessment system could be very useful for improving the compost utilisation towards sustainable composting in the developing countries.

The aim of this study is to develop a novel framework for the optimisation of downstream oil supply chains with emission-cost nexus and performance analysis. A P-graph based model has been developed to support the decisions of the distribution plan in the supply chain. This created the possibility to consider constraints, including the material balance, the sending capacity of refineries and storage depots, and the transport capacity of railways, barges and pipelines. Three scenarios, covering standard conditions, pipeline disruption, and demand increase, are analysed. The proposed novel method supports the decision-making of downstream oil supply chains and provides insight into the reduction of environmental influences. The results reveal that priority should be given to measures for reducing NOx emission (both Greenhouse and dangerous pollution gas) and the emission factors of barge transport, as this can bring great environmental benefit. When NOx emission for railways and barges is reduced by 5%, 1,435 kCNY/month could be saved. If the emission of the barges is reduced by 5%, this can save 1,289 kCNY/month of environmental cost. The proposed method is handy for analysis under non-standard conditions, such as transport facility disruption and demand increase. It would help in the design a distribution plan from a more comprehensive view, and to provide further direction for reducing the environmental footprint.

Energy plays a leading role in supporting the smart concepts, such as the Internet of Things and data storage, for the advanced development of cities and industries. The smart-concept makes use of the information and communication technologies (ICT) to supply information required for effective management. This Special Issue in Energy includes the latest developments in energy research presented at the 4th International Conference on Low Carbon Asia & Beyond (ICLCA′18) with the theme “Transition to Sustainable Energy System for Smart Cities and Industries”, held in Johor Bahru, Malaysia, on 24–26 October 2018. ICLCA hosted over 200 oral and 50 poster presentations. Thirty papers are included in this special issue which constitutes the latest developments in energy research. ICLCA serves as a yearly conference which provides a platform for the researchers and stakeholders from the academic community, industry sectors, and governments in Asia to share their experience, knowledge, and expertise in sustainability. The main purpose is to catalyse the transformation of low CO2 emissions development in the context of Asia and beyond. The paper covers a range of topics relevant to a sustainable energy system: (i) smart energy systems, (ii) low CO2 emissions technologies, (iii) biomass and pollution reduction, and (iv) renewable energy.

Energy is a fundamental element supporting societal development, particularly with the increasing dependency on the Internet of Things. It is also the main contributor to environmental impacts and subsequently, a potential sector for mitigation. Sustainable energy system design considers energy savings and energy efficiency, waste and consumption reduction, process efficiency enhancement, waste heat recovery, and integration of renewable energy. Emerging tools range from advanced Process Integration, modelling, simulation, and optimisation, to system analysis and assessment. This review covers selected emerging studies promoting sustainable system design, including the recent developments reported in the Special Issue (SI) of the 22nd Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES&rsquo, 19). The primary emphasis was to enhance the economic and environmental performance. However, social factors were also highlighted as essential for future sustainable development. The discussion and analysis in this review focus on the most recent developments of (a) heat integration and heat transfer, (b) integrated and newly developed heat exchangers, (c) integration of renewables, and (d) roles in economic and environmental sustainability. The key results are highlighted, and future research ideas are suggested according to their links to a broader context.

There is a wide array of biomass utilisation pathways to mitigate greenhouse gas emissions. The characteristic of biomass, the demand for products, and the local constraints determine the sustainability of utilisation. Generic principles and criteria can be applied to the analysis of specific instances. This work develops a decision-making tool for determining the most sustainable use of biomass for carbon management. The mathematical principles are based on break-even analysis and are visualised in the form of a graphical display for transparent communication of results to decision-makers. An essential feature of this tool is that it allows the Emissions-Cost Nexus to be considered in identifying the most sustainable biomass utilisation pathway under different baseline conditions. Economic instruments such as carbon emissions tax can also be determined and calibrated to direct decisions to specific pathways. The use of this tool is illustrated with a case study considering the pyrolysis of two different sources of biomass (residual biomass and energy crop) and plastic waste. Pyrolysis optimised for energy production is generally preferable unless biochar produced is at the quality for soil amendment. However, the change in baseline conditions, e.g. energy demand or carbon emission intensity, could overturn the initially selected utilisation. This result highlights the importance of a better standard to define avoided emissions for appropriate decision making. The case study also suggested that corn stover optimised for energy has a better emission-cost performance than optimised for biochar and carbon sequestration, unless the multiplier effect of biochar application to soil is higher than 1.4. The presented study shows the applicability of the developed method as a useful tool for sustainable biomass and product utilisation.

Assessments of hotspot analysis and process optimisation followed by improved design are essential to achieve cleaner production. Cleaner production also involves complex interactions with economic and social performance. It plays a substantial role in sustainable development. This contribution presents an overview of cleaner production achievements and selection of relevant recent work dealing with optimisation tools and process design as published in the Special Issue on Process Integration and Intensification for Sustainable Evolution via Resource and Emission Reduction. The cleaner production tools including Pinch Analysis, Process Graph, Artificial Intelligence and computer-aided modelling, are reviewed. The roles of waste streams as secondary resources process design in cleaner production and circular economy is also discussed. The highlights of the recent development contribute to the field of study by drawing out the attention for potential future research.

Municipal solid waste (MSW) is one of the issues associated with the growth of economic and urban population. The aim of this study is to develop an integrated design of waste management systems in support of a Circular Economy by P-graph (a bipartite graphical optimisation tool) as an effective decision support tool. The case study considers four MSW compositions based on different country income levels. Solving the P-graph model identifies the most suitable treatment approaches, considering the economic balance between the main operating cost, type, yield, quality of products, as well as the GHG emission (externality cost). The identification of near-optimal solutions by P-graph is useful in dealing with the trade-offs between conflicting objectives, e.g. local policy and practical implementation, that are difficult to monetise. For a lower-income country, the optimal solution includes a combination of at source separation, recycling, incineration (heat, electricity), anaerobic digestion (biofuel, digestate) and the landfill. It avoids an estimated 411 kg CO2eq/t of processed MSW and achieves a potential profit of 42 €/t of processed MSW. The optimisation generally favours mechanical biological treatment as the country income level rises, which affects the composition of the MSW. The relative prices of biofuel, electricity and heat (>20%) cause a significant impact on the highest-ranking treatment structure and overall profit. This study shows that the developed framework by P-graph is an effective tool for MSW systems planning. For future study, localised data inputs can be fed into the proposed framework for a customised solution and economic feasibility assessment.

Lignocellulosic waste (LW) is abundant in availability and is one of the suitable substrates for anaerobic digestion (AD). However, it is a complex solid substrate matrix that hinders the hydrolysis stage of anaerobic digestion. This study assessed various pre-treatment and post-treatments of lignocellulosic waste for anaerobic digestion benefiting from advanced P-graph and GaBi software (Thinkstep, Germany) from the perspective of cost and environmental performances (global warming potential, human toxicity, ozone depletion potential, particulate matter, photochemical oxidant creation, acidification and eutrophication potential). CaO pre-treatment (P4), H2S removal with membrane separation post-treatment (HSR MS) and without the composting of digestate is identified as the cost-optimal pathway. The biological (P7- Enzyme, P8- Microbial Consortium) and physical (P1- Grinding, P2- Steam Explosion, P3- Water Vapour) pre-treatments alternatives have lower environmental impacts than chemical pre-treatments (P4- CaO, P5- NaOH, P6- H2SO4) however they are not part of the near cost optimal solutions. For post-treatment, the near cost optimal alternatives are H2S removal with organic physical scrubbing (HSR OPS) and H2S removal with amine scrubbing (HSR AS). HSR AS has a better performance in the overall environmental impacts followed by HSR MS and HSR OPS. In general, the suggested cost-optimal solution is still having relatively lower environmental impacts and feasible for implementation (cost effective). There is very complicated to find a universal AD solution. Different scenarios (the type of substrate, the scale, product demand, policies) have different constraints and consequently solutions. The trade-offs between cost and environment performances should be a future extension of this work.

Transportation is widely recognised as the main contributors to the air pollutants emission. However, the concern in freight mode selection is relatively low compared to that of greenhouse gas (GHGs) / CO 2 emission. This study identifies the relationship between the air pollutants and GHGs through an illustrative case of transporting goods from Shanghai to Hong Kong. The transport option with low GHGs emission did not necessary an option with low air pollutants (SO x , NO x , Particulate Matter) emission. The contradict results are also reflected in the case of water transportation. The limitation of life cycle study (transporting and distribution stage) in evaluating the environmental footprint is also discussed by using the case of the food product. The available studies are either excluding the distribution stage (by ship) or only considering the GHGs emission in assessing the environmental component. This study highlights the role of air pollutants in freight mode selection and the need for a comprehensive system boundary for a better decision-making.

This study introduces a new graphical decision-making tool to facilitate the rapid selection of transportation modes with minimum energy consumption or emissions, indicating the most sustainable transportation mode. Greenhouse gas (GHG) and air pollutants (NOx, PM and SO2), together with a composite price-weighted total environmental burden (TEB), are considered in the analysis. The graphical tool, which has a similar appearance to a phase diagram, presents a map of energy use (or emission) of different transportation modes based on the values of the ratio of the transportation distances (R) and the absolute load (L). A freight transportation case study (Rotterdam to Antwerp and Genova) demonstrates the construction and application of the graphical tool. For this case study, the electric train is the transport mode that offers the lowest energy consumption and minimum TEB. The graphical decision tool can also indicate the next-best solutions when one or more options (e.g. electric train) are not available. In this scenario, general cargo shipping achieves the lowest GHG emission, but heavy lorry imposes the lowest TEB. The developed tool further demonstrates the impacts of possible future fuels and technology developments on transportation selection, including renewable biodiesel and transport electrification under different grid mixes (e.g. Latvia, Sweden and EU-28). Further criteria, including economics, can be included for future study using the proposed tool as a foundation. The graphical approach transforms the transport selection problem into an easily understandable format from which arises sound solutions.

In this paper, the energy and environmental impacts of a passive retrofit action, involving the installation, on an office building, of a second-skin system with the external layer made of a PVC-coated polyester fabric, were evaluated in terms of primary energy saving and carbon dioxide equivalent emissions. The primary energy consumption and the carbon dioxide equivalent emissions associated with the considered case studies were evaluated using the software TRNSYS, across a whole year. The study was carried out considering three Iranian cities (Tabriz, Teheran and Bandar Abbas) in three different climates (cold, temperate and hot) upon varying the orientation of the two main façades of building (north-south and east-west orientation). The simulation results highlighted good results when the building is east-west oriented, up to -12.9% for the reduction of primary energy consumption (in Teheran) and up to -42.1 MgCO2,eq (in Tabriz) for the carbon dioxide equivalent emissions.

Alternative fuels are crucial for decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is beneficial since it could effectively integrate waste management with the energy production sector. This is especially important for non-recyclable waste like rigid polyurethane foam, in which recycling implies a complex and expensive processes. Lately, the co- pyrolysis of waste plastics and biomass was introduced, since the synergistic effect might enhance the product properties compared to those of individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption and even more, it avoids the usage of raw feedstock which could be utilized more effectively elsewhere. Thermogravimetric analysis is performed to determine the thermal degradation mechanism of investigated mixtures with the intention to find the most appropriate utilisation method. Co- pyrolysis was conducted for three mixtures with following biomass/polyurethane ratios: 75-25 %, 50-50 %, 25-75 %, over a temperature range of 30- 800 °C, at two heating rates 10 and 20 °C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis in order to determine effective activation energy and to provide a detailed analysis of the thermal degradation process for the considered samples. This work aimed to identify main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and to provide the influence of the mixture composition on the considered thermochemical conversion process. Kinetic analysis of the co-pyrolysis process for waste materials is seldom in literature, and this represents the main novelty of this work.

Ammonia appears to be a potential alternative fuel that can be used as a hydrogen vector and fuel for gas turbines and internal combustion engines. Chemical mechanisms of ammonia combustion are important for the development of ammonia combustion systems, but also as a mean of investigation of harmful NOx emissions, so they can be minimized. Despite of large body of experimental and modeling work on the topic of ammonia combustion, there is still need for further investigation of combustion kinetics. Taking the above stated, the object of this work is further numerical study of ammonia combustion chemistry under practical industrial conditions. After literature review, two validation cases, namely swirl premixed burner and MILD burner, were simulated with the aim of evaluating the performance of different turbulence models on combustion phenomena. Influence of turbulence chemistry interaction has also been investigated. It is expected that this study will contribute to enhance the current knowledge by providing new insights in ammonia burning conditions closely resembling those in industrial applications and consequently help to design real industrial burning systems.

The improvement of the energetic performances of the building envelope represents a crucial aspect to increase the buildings energy efficiency and indoor environmental quality. In recent years, one of the most appreciated design solutions in the worldwide architecture panorama is the Double-Skin Façade. A lot of different technologies and innovative materials have been proposed lately to improve or modify Double-Skin Façade appearance and energy efficiency. Unfortunately, there is still a lack of numerical models able to reproduce coherently and comprehensively the behaviour of complex Double-Skin Façades, let alone the cases in which innovative materials or geometries are used. Therefore, two identical test-cells (called GEMINI) for on-site acoustic, visual and thermal characterization of different full-scale modules for Double-Skin Façades have been designed and are currently under construction at University of Campania “Luigi Vanvitelli”. In this paper, their structure, equipment and measurements layouts are presented and described in detail.

Today, strategies for emergency preparedness, in presence of accidental scenarios in high-risk plants with releases into the atmosphere, have become a priority. To achieve this goal, it is important to have forecast meteorological data in local areas to use in dispersion and transport models and so to respond in advance emergency situations. The paper reports results of research performed to develop a new tool, called FORCALM that is capable to elaborate European Centre for Medium-Range Forecasts (ECMWF) forecast data to use for simulations by CALMET/CALPUFF modeling system. A case study, relevant to an accident occurred in Mediterranean Refinery at Milazzo (Italy), has been examined to validate the procedure and the capacity to evaluate the transport and depositions pollutant in terms of forecast information. The results were compared with those obtained using CALMET/CALPUFF simulations based on measured meteorological, covering the area under study.