A material flow analysis of the 2012 Swiss waste management system is presented, highlighting the material content available from waste. Half of municipal solid waste (MSW) is materially recycled and the other half thermally treated with energy recovery. A key component of an industrial ecosystem is increasing the resource efficiency through circulating materials. Recycling rates (RRs), an indicator for the circulating behavior of materials, are often used as measure for the degree of circularity of an economy. This study provides an in-depth analysis of the recycling of paper, cardboard, aluminum, tinplate, glass, and polyethylene terephthalate (PET) from MSW in Switzerland by splitting the RRs into closed-and open-loop collection rate (CR) and RRs. Whereas CR refers to collected material that enters the recycling process, RRs measure the available secondary resources produced from recycling processes. For PET, the closed-loop CR of 45% and the open-loop CR of 40% compare to an RR of 31% and 37%, respectively (including exports and recycling of polyethylene and metals from collection). Official collection rates for paper and cardboard are very high (97%), whereas CR of 74% and 89% and RR of 59% and 81% for paper and cardboard, respectively, were found in the present study (including export). For a majority of the separately collected materials investigated, the rates that are determined are substantially lower than those that are officially communicated. Furthermore, given that official rates often do not provide information on the availability of secondary materials, the improvement potential for increased resource recovery is hidden. Keywords: circular economy closed-loop industrial ecology material flow analysis municipal solid waste open-loop Supporting information is linked to this article on the JIE website

Summary The multifunctional character of resource recovery in waste management systems is commonly addressed through system expansion/substitution in life cycle assessment (LCA). Avoided burdens credited based on expected displacement of other product systems can dominate the overall results, making the underlying assumptions particularly important for the interpretation and recommendations. Substitution modeling, however, is often poorly motivated or inadequately described, which limits the utility and comparability of such LCA studies. The aim of this study is therefore to provide a structure for the systematic reporting of information and assumptions expected to contribute to the substitution potential in order to make substitution modeling and the results thereof more transparent and interpretable. We propose a reporting framework that can also support the systematic estimation of substitution potentials related to resource recovery. Key components of the framework include waste‐specific (physical) resource potential, recovery efficiency, and displacement rate. End‐use–specific displacement rates can be derived as the product of the relative functionality (substitutability) of the recovered resources compared to potentially displaced products and the expected change in consumption of competing products. Substitutability can be determined based on technical functionality and can include additional constraints. The case of anaerobic digestion of organic household waste illustrates its application. The proposed framework enables well‐motivated substitution potentials to be accounted for, regardless of the chosen approach, and improves the reproducibility of comparative LCA studies of resource recovery.

India is a major emitter of mercury, a pollutant of global importance. However, quantitative information on mercury flows in the country is lacking. Here, we quantify major transfer pathways for anthropogenic mercury, its emissions to the environment (air, water, soil), and storage in consumer products and anthropogenic sinks (e.g., landfills) in India in the period 2001-2020, and evaluate the potential influence of six pollution control measures. Total mercury emissions in India were approximately 415 tonnes in 2001, 310 tonnes in 2010, and are projected to rise to 540 tonnes in 2020. In 2010, 76% of these emissions went to the atmosphere. The most important emission sources to atmosphere are coal power plants and zinc production. Pesticides were the most important source for emissions to soil in 2005 and dental amalgam in later years. Mercury stocks in products rose from 700 tonnes in 2001 to 1125 tonnes in 2010, and in landfills and ash-made structures (e.g., embankments) from 920 tonnes in 2001 to 1450 tonnes in 2010. These stocks are expected to rise further and may be regarded as stored toxicity, which may become a concern in the future. Total mercury emissions can be reduced by about 50% by combining pollution control measures that target different mercury emission sources.

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Resources have received significant attention in recent years resulting in development of a wide range of resource depletion indicators within life cycle assessment (LCA). Understanding the differences in assessment principles used to derive these indicators and the effects on the impact assessment results is critical for indicator selection and interpretation of the results. Eleven resource depletion methods were evaluated quantitatively with respect to resource coverage, characterization factors (CF), impact contributions from individual resources, and total impact scores. We included 2247 individual market inventory data sets covering a wide range of societal activities (ecoinvent database v3.0). Log-linear regression analysis was carried out for all pairwise combinations of the 11 methods for identification of correlations in CFs (resources) and total impacts (inventory data sets) between methods. Significant differences in resource coverage were observed (9-73 resources) revealing a trade-off between resource coverage and model complexity. High correlation in CFs between methods did not necessarily manifest in high correlation in total impacts. This indicates that also resource coverage may be critical for impact assessment results. Although no consistent correlations between methods applying similar assessment models could be observed, all methods showed relatively high correlation regarding the assessment of energy resources. Finally, we classify the existing methods into three groups, according to method focus and modeling approach, to aid method selection within LCA.

SummaryIn electric arc furnaces (EAFs), different grades of steel scrap are combined to produce the targeted carbon steel quality. The goal of this study is to assess the influence of scrap quality on the recycling process and on the final product by investigating the effect of the scrap mix composition, and other inputs, for example, preheating energy, on the electricity demand of the melting process. A large industrial data set (empirical data set of ß20,000 individual heats recorded during 2.5 years at a Swiss EAF site) is analyzed using linear regression. The influence of scrap grades on electricity demand are found to correlate strongly with their respective quality; specific electricity demand is up to 45% higher for low-quality scrap than for high-quality scrap. Given that chemical compositions of scrap grades are highly variable and often unknown, average concentrations are determined using linear regression with scrap input as the predictors and the amounts of the investigated elements in liquid steel as the dependent variable. The lowest quality (highest copper and tin concentrations) and the highest electricity demand in the EAF are found for scrap recovered from bottom ashes of municipal solid waste incineration. Although even with low-quality scrap input steel recycling is environmentally superior to primary steel production, the optimization potential in terms of energy efficiency and resource recovery, for example, through pretreatment, seems to be substantial. Keywords:electric arc furnace energy industrial ecology life cycle management recycling scrap grade Supporting information is linked to this article on the JIE website