This contribution presents the state of the art of economy-wide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we outline system ...definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R2 of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.
Summary
This contribution presents the state of the art of economy‐wide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we ...outline system definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R2 of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.
The resilience and low cost of plastics has made their usage ubiquitous, but is also the cause of their prevalence and longevity as waste. Plastic pollution has become a great concern to the health ...and wellbeing of ecosystems around the world; microplastics are a particular threat, due to their high mobility, ease of ingestion by wildlife, and ability to adsorb and carry toxic contaminants. Material flow analysis has been widely applied to examine stocks and flows of materials in other industries, and has more recently been applied to plastics to examine areas where waste can reach the environment. However, while much research has gone into the environmental fate of microplastics, degradation strategies have been a lesser focus, and material flow analysis of microplastics has suffered from lack of data. Furthermore, the variety of plastics, their additives, and any contaminants pose a significant challenge in degrading (and not merely fragmenting) microplastic particles. This review discusses the current degradation strategies and solutions for dealing with existing and newly-generated microplastic waste along with examining the status of microplastics-based material flow analysis, which are critical for evaluating the possibility of incorporating microplastic waste into a circular economy. The degradation strategies are critically examined, identifying challenges and current trends, as well as important considerations that are frequently under-reported. An emphasis is placed on identifying missing data or information in both material flow analysis and degradation methods that could prove crucial in improving understanding of microplastic flows, as well as optimizing degradation strategies and minimizing any negative environmental impact.
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•Microplastic remediation is trending towards sustainable options.•Challenges arise from variety of plastics, additives, and contaminants.•Completeness of degradation is important, but not often investigated.•Additional reporting of parameters and characterization is needed.•Degradation techniques could be combined to address their respective disadvantages.
Assessing progress towards environmental sustainability requires a robust and systematic knowledge base. Economy-wide material flow accounting (ew-MFA) is an established method to monitor resource ...use across scales and its headline indicators are widely used in policy. However, ew-MFA is currently limited by its empirical focus on annual flows of material and energy, because it neglects the pivotal role of in-use material stocks of manufactured capital. Explicitly integrating in-use stocks enables new insights into a range of Ecological Economics' topics, such as the biophysical assessment of socio-economic systems, the circular economy and stock-flow consistent scenarios.
Herein, we conceptually and practically expand the ew-MFA framework towards jointly addressing material flows, in-use stocks of manufactured capital and waste, using a fully consistent dynamic model of Material Inputs, Stocks and Outputs (MISO-model). We review the stock modelling literature, propose a novel distinction of stock-driven versus inflow-driven approaches and situate the MISO-model as the latter. We then investigate the global dynamics of socio-metabolic flows and in-use stocks from 1900 to 2014, explore model sensitivities and quantify and attribute uncertainty. Two exemplary scenarios are presented. Through these innovations for ew-MFA, we enable a dynamic and comprehensive assessment of resource use, stocks and all wastes in the socio-economic metabolism.
•Use-phase, in-use stock dynamics, waste and recycling crucial next steps for ew-MFA•Review of stock-modelling yields new classification: stock-driven vs. inflow-driven•Dynamic inflow-driven model of Material Inputs, Stocks and Outputs (MISO-model v1)•Global in-use stocks increase 26-fold to 928 Gt ± 5% between 1900 and 2014•Two exemplary scenarios on the importance of stock dynamics are shown
•The demand for aluminium is forecasted on an alloy-level per industrial sector.•A global aluminium scrap surplus of 5.4 million tonnes/year is forecasted in 2030.•Wrought-to-wrought recycling is ...essential to mitigate the growth of the scrap surplus.•A sampling campaign is undertaken to experimentally verify the literature data.•The evolution of the scrap surplus is sensitive to trends in the automotive industry.
The probable emergence of a global aluminium scrap surplus in the coming decade is one of the main incentives for the aluminium recycling industry to invest in new methods and technologies to collect, sort and recycle aluminium scrap. However, due to the considerable uncertainty in the evolution of the global scrap surplus, it is difficult for policymakers and the recycling industry to accurately estimate the economic and environmental advantages of implementing enhanced sorting and recycling methods. The International Aluminium Institute (IAI) has developed a model to track and forecast the global flows of aluminium, but this model is not extensive enough to estimate the scrap surplus evolution. Therefore, this paper introduces an alloy series resolution to the supply and demand of aluminium in the IAI’s global flow model and estimates the composition of the recovered scrap flows to improve the estimate of the technical potential of secondary alloy production. The estimated scrap surplus evolution is subjected to a sensitivity analysis, considering the most critical parameters, including the speed of electrification in the automotive sector, the recovered scrap’s composition and the lifetime of aluminium products. In addition, the estimated composition of the recovered aluminium scrap in the model is compared to composition measurements of alumimium scrap collected at a Belgian recycling facility as a means of validation. This study allows to estimate that the global aluminium scrap surplus will emerge soon and reach a size of 5.4 million tonnes by 2030 and 8.7 million tonnes by 2040, if currently adopted aluminium sorting and recycling methods are not improved.
In January 2018, the Chinese government implemented a ban on importation of foreign waste, including waste plastics and other miscellaneous waste. Consequently, this ban has changed the global ...plastic recycling options. The aim of this study is to clarify the environmental impact of the ban between China and Japan, which is the largest exporter of plastic waste. The question of whether these policies are fundamentally helping to reduce the environmental burden has also been discussed from the viewpoints of China and Japan. Plastics have been classified into seven categories. Material flow analysis (MFA) and CO2 emissions derived in the MFA were applied to examine the material flow of waste plastics and compare CO2 emissions of virgin and recycled resins in Japan and China before, and after, the ban. A scope for the MFA including the recycling process of waste plastics, virgin resin production, and shipping between countries was proposed, and the transition of the material flow and CO2 emissions caused by China's waste import ban were evaluated. Material flow relevant to both Japan and China was set as the scope. Material flow crossing the scope, such as import of waste plastic into China from countries other than Japan, and export of waste plastic from Japan to countries other than China before the ban was excluded. The main finding of MFA is that the transition in material flow between 2016 and 2018 in China demonstrated high virgin resin imports and exports in 2016, and 28% of recycled waste plastics in China were derived from imported waste plastic. After the ban, the amount of waste plastic imports decreased by more than 99%, causing domestic virgin resin production to increase. Other findings include that CO2 emissions of the input of virgin materials increased by up to 10%, and the CO2 emissions derived from virgin resin production increased by up to 11% in 2018 compared those reported in 2016. With this transition, the CO2 emissions of 1 kg of raw materials in 2018 increased by 0.24 kg compared with 2016. In contrast, Japan's exports decreased, and domestic recycled plastic input increased. The CO2 emissions of 1 kg of raw materials in 2018 decreased by 0.07 kg compared with 2016.
•Impact of China's waste plastic import ban was analyzed using MFA.•China increased virgin resin at the expense of reduced imports of waste plastics.•CO2 emissions from the production of 1 kg of virgin resin increased in China.•Japan's recycling increased at the expense of reduced exports of waste plastics.•CO2 emissions from the production of 1 kg of recycled resin increased in Japan.
The long-run effect of the synergy between natural resource consumption and environmental sustainability varies across countries depending on the economic structure. However, the transboundary effect ...of natural resource capital underscores the importance of environmental convergence. Here, we map ecological performance, biocapacity, and carbon footprint of nations. We assess the socio-economic drivers of environmental performance and convergence using novel cross-country time series techniques. We find that the expansion of biocapacity of nations has an ameliorating effect on ecological performance. The hotspot countries of environmental performance include Australia, Brazil, China, Germany, India, Japan, Russia, and the US. We confirm the existence of environmental convergence across nations — implying that the disparity in carbon and ecological footprint between higher-income and lower-income countries will converge in the long-run. This accentuates the need for global partnership towards achieving environmental sustainability.
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•We assess ecological footprint, carbon footprint, biocapacity and ecological status of nations.•We utilize both econometric and machine learning-based estimation methods.•Top global ecological footprint hotspots include the US, China, Russia, India and Japan.•Disparity in carbon and ecological footprint between income groups converge in the long-run.•Trade-led carbon footprint confirms a potential transboundary carbon-embedded trade.
Phosphorus (P) is an essential and limited resource. Municipal wastewater is a promising source of P via reuse and could be used to replace P derived from phosphate rocks. The agricultural use of ...sewage sludge is restricted by legislation or is not practiced in several European countries due to environmental risks posed by organic micropollutants and pathogens. Several technologies have been developed in recent years to recover wastewater P. However, these technologies target different P-containing flows in wastewater treatment plants (effluent, digester supernatant, sewage sludge, and sewage sludge ash), use diverse engineering approaches and differ greatly with respect to P recycling rate, potential of removing or destroying pollutants, product quality, environmental impact and cost. This work compares 19 relevant P recovery technologies by considering their relationships with existing wastewater and sludge treatment systems. A combination of different methods, such as material flow analysis, damage units, reference soil method, annuity method, integrated cost calculation and a literature study on solubility, fertilizing effects and handling of recovered materials, is used to evaluate the different technologies with respect to technical, ecological and economic aspects. With regard to the manifold origins of data an uncertainty concept considering validity of data sources is applied. This analysis revealed that recovery from flows with dissolved P produces clean and plant-available materials. These techniques may even be beneficial from economic and technical perspectives under specific circumstances. However, the recovery rates (a maximum of 25%) relative to the wastewater treatment plant influent are relatively low. The approaches that recover P from sewage sludge apply complex technologies and generally achieve effective removal of heavy metals at moderate recovery rates (~40–50% relative to the WWTP input) and comparatively high costs. Sewage sludge ash is the most promising P source, with recovery rates of 60–90% relative to the wastewater P. The costs highly depend on the purity requirements of the recycled products but can be kept comparatively low, especially if synergies with existing industrial processes are exploited.
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•Wastewater P can be recovered, but an integrated technology assessment is missing.•Various methods and parameters are chosen to deliver an holistic picture.•This assessment comprises technological, environmental and economic criteria.•Sludge ash combines most promising P source and promising recovery technologies.•Technologies show significant tradeoff between recovery rate, depollution and cost.
With the rapid development of new infrastructure in China, the demand for copper has increased significantly. In 2021, copper consumption in this sector accounted for 9.1% of China's total ...consumption, becoming a new driving force for copper demand. This study analyzed copper flow characteristics and primary driving factors in China's new infrastructure sectors using the material flow analysis method, quantified the environmental loads of the metabolic processes, and predicted copper demand in the new infrastructure sectors by 2030 through scenario analysis. The primary conclusions drawn are as follows: In 2021, copper consumption in new infrastructure sectors was 1,225,700 tons, with the rail transportation sector accounting for 59.6% and the artificial intelligence sector accounting for 0.6%. The rail transportation sector had the largest total environmental load, with carbon emissions of approximately 3,513,372 tons. From the perspective of tons of copper products, the 5G sector had the highest environmental load, while the big data centers had the lowest. In the seven sectors of new infrastructure, the environmental load contribution rates across the four stages showed little variation, with their proportions being 49.0, 29.8, 15.8, and 5.4%, respectively. Recycling of discarded copper products can effectively reduce industrial energy consumption and carbon emissions. Under the three scenarios set in this study, the copper demand in the new infrastructure sector by 2030 will be 3.856, 3.233, and 2.625 million tons, respectively. Using wind energy to replace coal in copper production can reduce carbon emissions by approximately 43.2%.
•Rapid new infrastructural development drives rapid growth in copper consumption.•Quantified the environmental impact of copper usage in new infrastructure field through lifecycle assessment methods.•Copper demand in new infrastructure field projected to increase significantly by 2030.•Replacing 50% coal in copper production with wind energy can reduce CO2 emissions.
•A review of material and energy flows in the iron and steel industry is provided.•Material scheduling and energy saving technologies for steelworks are reviewed.•Forecasting and optimization models ...of material and energy flows are introduced.•Challenges of current studies on material and energy flows are identified.•Future directions of material flow and energy flow research are discussed.
Integrated analysis and optimization of material and energy flows in the iron and steel industry have drawn considerable interest from steelmakers, energy engineers, policymakers, financial firms, and academic researchers. Numerous publications in this area have identified their great potential to bring significant benefits and innovation. Although much technical work has been done to analyze and optimize material and energy flows, there is a lack of overview of material and energy flows of the iron and steel industry. To fill this gap, this work first provides an overview of different steel production routes. Next, the modelling, scheduling and interrelation regarding material and energy flows in the iron and steel industry are presented by thoroughly reviewing the existing literature. This study selects eighty publications on the material and energy flows of steelworks, from which a map of the potential of integrating material and energy flows for iron and steel sites is constructed. The paper discusses the challenges to be overcome and the future directions of material and energy flow research in the iron and steel industry, including the fundamental understandings of flow mechanisms, the dynamic material and energy flow scheduling and optimization, the synergy between material and energy flows, flexible production processes and flexible energy systems, smart steel manufacturing and smart energy systems, and revolutionary steelmaking routes and technologies.
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