查看更多>>摘要：We present a material flow and stock analysis for cobalt use and waste in the United States from 1996 to 2020, including the separation of cobalt flows into six product groups and five end-use sectors. The results demonstrate the importance of U.S. manufacturing for air travel, energy storage, cemented carbides, and numerous other applications. Battery use in the United States has become the primary factor in cobalt demand, but the batteries are manufactured mainly elsewhere. The correlation of cobalt products to principal end-use sectors provides an informed view of the location of cobalt in in-use stocks. Two approaches could primarily address these stocks: enhanced recycling of batteries in consumer/business electronics and implementing cobalt-free substitutes for chemical uses and future battery technologies. Overall, cobalt's uses are as diverse and societally crucial as any element in the periodic table but have heretofore not received the levels of attention they deserve.
查看更多>>摘要：This study proposes a novel methodology to calculate reuse and apply this to Flanders. We combine available data from the Flemish reuse network about its reselling of reusable goods with new survey data about disposal and acquisition behaviours of a representative sample of 1500 Flemish citizens. Using these data, we map the amount of reuse channelled through various exchange channels and calculate a reuse estimate (Total Reused Goods-TRG). In addition, we nuance its environmental impact through calculating its replacement rate. Our results reveal an important share of informal channels beyond formal channels. Moreover, a new estimate of 33.8kg reuse/capita is calculated for Flanders, which is 6.3 times higher than the current estimate of 5.4kg reuse/ capita. Furthermore, only 28% of reusable goods prevent the acquisition of new goods. This new methodology is the first to calculate a comprehensive reuse measure which may form the basis for new regional reuse indicators.
查看更多>>摘要：Barriers to access-based consumption (ABC) have been extensively studied in different strands of literature. However, cumulative knowledge is not organized to date, and a comprehensive overview of barriers identified by empirical studies in diverse strands is lacking. Such a picture is essential for laying the ground for further change oriented research and actual changes in practice. This article reports on the results of a systematic review on barriers to transitioning from ownership-to access-based consumption. The review focuses on the literature strands product-service systems, circular economy, sharing economy, and collaborative consumption. Through open and axial coding of 289 barriers reported in 45 empirical studies, we found 17 themes of barriers concerning consumers, business, and society. The analysis of the barriers reveals four significant insights important for the research and practitioner community: (1) the overall experience of ABC and trust mechanisms need to be better understood; (2) organizational aspects in traditional business need a system change; (3) regulation plays a fundamental role in making ABC work for business, society, and sustainability; and (4) sharing risks and experimentation for new learnings are necessary. These four major insights suggest that consumers need business and government to offer enabling conditions for ABC - spanning from raising awareness and understanding to improving user experience. Furthermore, businesses need governments to create the necessary structures to support ABC offerings - from decreasing risks to increasing incentives. How and which mechanisms can further facilitate circular behaviors is a salient topic for future investigations.
查看更多>>摘要：Afforestation is widely recognized as an effective way to achieve carbon neutrality. But is afforestation the best strategy for absorbing and fixing carbon dioxide and effectively reducing the greenhouse effect? This paper conducted a comparative study on woody plants and herbaceous plants in terms of carbon sequestration capacity, energy equivalent and growth environment. The result demonstrated that it is better to plant herbaceous plants than woody plants to achieve rapid carbon fixation and recycling for reducing the greenhouse effect and impact on the ecological environment.
查看更多>>摘要：Ground-level ozone (GLO) has been widely recognized as a critical air pollutant that has the potential to induce various adverse environmental and health effects. To eliminate its hazardous impacts, the development of an accurate and effective approach to forecast the upcoming pollution concentration levels is in urgent need. Recent studies show that machine learning algorithms have excellent abilities in ground-level ozone concentration forecasting, however many of their forecasting models do not consider the contributing effects on meteorological measurements and traffic situations which were also identified as potential influencing factors to ground-level ozone concentration by some previous research. In the meantime, most of the existing models target shortterm forecasting with rough temporal resolutions, such as daily and weekly scales. This paper aims to propose a methodology that can provide long-term GLO concentration forecasting with a high temporal resolution. To achieve this, a frequent pattern mining approach is utilized to analyze the local intercorrelation between GLO concentration and contributing factors such as meteorological parameters and transportation situations. Then, a series of machine learning algorithms were identified to forecast the ground-level ozone concentration levels using traffic and meteorological measurements data. A case study was conducted in the Houston region with 10 years of historical measurements, each of the historical ground-level ozone concentration records is associated with a series of meteorology and traffic situation parameters. Data from 2010 to 2019 was used to select and train the machine learning models, and data from 2020 was used to perform the final validation and evaluation. Results show that the extreme gradient boost (XGBoost) machine learning algorithm provides the most accurate prediction of the hourly ground-level ozone concentration on a yearly scale, which shows the annually forecasting ability and the robustness of the model built. The proposed approach could be applied to other similar regions and other critical air pollutants that are also influenced by transportation and meteorological factors.
查看更多>>摘要：As a measure towards achieving carbon neutrality and sustainability in the wastewater treatment industry, an autotrophic PN/HAP-A (airlift reactor/EGSB reactor) system is proposed in this study. The undiluted effluent from an AnMBR digesting municipal organic waste was applied for the practical validation of the system. With continuous feeding mode, the high efficiency, stability and operational simplicity were confirmed. In both reactors, the sludge manifested macro-aggregates and HAP-anammox granules with a satisfactory settling velocity and well-functional microorganisms. The alkalinity/IC consumptions and the buffer capacity were given individually and systematically. The elemental flow and potentials of precipitations indicated the high possibility and viability of phosphorus recovery by the formation of HAP, and in turn, the accumulation of precipitates in the biomass enhanced the settling velocity of the sludge. It is confirmed that the PN/HAP-A system is a promising approach to achieving nitrogen removal and phosphorus recovery from high-strength wastewater.
查看更多>>摘要：Economics of scale refer to the benefits in cost, efficiency, and sustainability yielded with increasing size. Driven by shrinking household size and urban sprawl, household or urban economies of scale have been declining in recent decades. The declining scale economies may also affect CO(2 )emissions, which, however, have not been well understood due to a mixture of other factors. Based on the Chinese urban household survey data and the metrics of urban density, hierarchical linear models at two levels of city and household are developed to investigate the effects of household and urban economies on residential CO2 emissions per capita and the interaction between these two effects. Our estimates confirm the existence of household and urban economies of scale by showing that an additional household member and a 1% increase in urban density could reduce emissions per capita by 2.8% and 0.039%, respectively, and these scale economies can be partially substitutable due to a similar sharing mechanism. Using China's historical census data and extrapolating from our estimate, we also find that over the past 40 years, China's declined household and urban economies increased emissions per capita by 5.0% and 1.1%, respectively, when controlling for other variables. Although the household and urban economies of scale may not be sufficient to offset total emissions caused by rising affluence and urbanization, the emission benefits of scale economies suggest that imitating households' sharing acts at the urban scale, such as carpooling and secondhand goods trade, will contribute to emission mitigation and broaden the climate solution space during the urbanization process.
查看更多>>摘要：Theoretically, the concept of digitalization would promote energy sustainability, because it improves energy efficiency through behavioral changes related to energy use. However, it may also conversely cause excessive energy consumption if not managed well. Nowadays, digitalization has been widely adopted in ASEAN, not only in the economic sector but also in social activities. This development is believed to improve the energy efficiency towards energy sustainability in the long-run. As digitalization is closely related to energy use behavior that will consequently promote energy efficiency and sustainability, comprehensive statistical analysis is essential to uncover the truth and debunk incorrect potential energy consumption behavioral patterns of digitalization and its effects on energy consumption. This study investigates the impact of digitalization on both total and disaggregated energy consumption. We use a balance panel dataset that covers 1990-2018 in five major ASEAN countries. The Cross-Sectional Augmented Autoregressive Distributed Lag (CS-ARDL) approach is employed to estimate both long run and short run elasticity of digitalization. The results conclude that digitalization does indeed bring down energy consumption levels in total and in all disaggregated sources. Hence, more investment into increasing and enhancing digital infrastructure is recommended towards achieving energy sustainability strategic objectives.
Klemes, Jirf JaromfrChin, Hon HuinVarbanov, Petar SabevYou, Fengqi...
14页
查看更多>>摘要：The worldwide plastic waste accumulation has posed probably irreversible harm to the environment, and the main dilemma for this global issue is: How to define the waste quality grading system to maximise plastic recyclability? This work reports a machine learning approach to evaluating the recyclability of plastic waste by categorising the quality trends of the contained polymers with auxiliary materials. The result reveals the hierarchical resource quality grades predictors that restrict the mapping of the waste sources to the demands. The Pinch Analysis framework is then applied using the quality clusters to maximise plastic recyclability. The method identifies a Pinch Point - the ideal waste quality level that limits the plastic recycling rate in the system. The novel concept is applied to a problem with different polymer types and properties. The results show the maximum recycling rate for the case study to be 38 % for PET, 100 % for PE and 92 % for PP based on the optimal number of clusters identified. Trends of environmental impacts with different plastic recyclability and footprints of recycled plastic are also compared.
查看更多>>摘要：Light earth is a natural insulating material composed of earth and vegetal fibres. It can be used to insulate existing and new buildings to reduce energy and resources consumption, and excavated earth generation by the construction sector. A pedological database is crossed with suitability thresholds in order to evaluate spatially the availability of earth resources. Then, the soil suitability is mapped, and suitable soil amounts metrics are estimated for Brittany territory. A sensitivity analysis is performed to understand the potential variability of the results. Study estimates that 48% of Brittany's soil horizons are suitable for light earth building. Every year, 1.3 Mt of suitable soil are excavated in Brittany. Using only these excavated earths, all existing and new buildings in Brittany could be insulated with light-earth in less than 8 years. This study shows that suitable earth availability is not a limiting factor to develop light earth insulation in Brittany.
NSTL
Elsevier