Towards the definition of WEEE recycling targets in Ecuador. A case of study for mobile phones.

The rise of consumption patterns of electrical and electronic equipment (EEE) and the generation of waste EEE (WEEE) has been strongly increasing globally. Recycling rates (RRs) are one of the main indicators for monitoring the progress towards a circular economy and establishing recovery and treatment schemes. For this reason, this study discusses the setting of recycling targets for WEEE in Ecuador, using mobile phones as a case study. Firstly, the generation of mobile phone waste from 2012 to 2018 is estimated based on literature review. The most appropriate model for estimating WEEE generation is selected according to the applicable market conditions, input requirements and available data. Then, the composition of a mobile phone is determined through an extensive literature review. Based on these results, the materials' environmental impact and potential economic value are approximated using the ReCiPe Endpoint (H, A) method and the prices of virgin materials, respectively. The estimation shows that in Ecuador an average of 2 million devices are discarded every year, which represents an interesting source of resources but currently does not have appropriate management. Ecuador has implemented regulatory frameworks in favour of the integral management of these wastes. However, mass-based collection targets still appear to be the only available measure. Therefore, national results on electronics recycling do not allow adequate monitoring of progress towards a circular economy and largely neglect environmental aspects and economic potential.

A high-resolution dataset on the plastic material flows in Switzerland.

A material flow analysis of the main plastic types used and arising as waste in Switzerland in 2017 is conducted, including consideration of stock change. Seven main plastic application segments are distinguished (packaging; building and construction; automotive; electrical and electronic equipment; agriculture; household items, furniture, leisure and others; and textiles), further divided into 54 product subsegments. For each segment, the most commonly used plastic types are considered, in total including eleven plastic types (HDPE, LDPE, PP, PET, PS, PVC, ABS, HIPS, PA, PC, and PUR). All product life cycle stages are regarded, including the determination of the product subsegments in which the individual post-consumer secondary materials obtained from mechanical recycling are applied. The underlying data are gathered from official statistics and administrative databases, scientific literature, reports by industry organizations and research institutions, websites, and personal communication with stakeholders. The compiled data are then reconciled. All flow data are provided and depicted in two Sankey diagrams: one diagram shows the material flows on a product-subsegment level and the second one on a plastic-type level. Users may retrieve the data with a script and transfer them into a relational database. The present material flow analysis data are used as a basis for the scenario analysis in Klotz et al. [1]. Besides scenario modelling, the data can be used in conducting life cycle assessments. Both utilizations can serve as a support for designing future plastic flow systems.

Limited utilization options for secondary plastics may restrict their circularity.

Plastic recycling can provide environmental benefits by avoiding the detrimental impacts of alternative disposal pathways and enabling the substitution of primary materials. However, most studies aiming at increasing recycling rates have not investigated how the resulting secondary materials can be utilized in product manufacturing. This study assesses the future substitution potential of primary with secondary plastics, building on a material flow system of 11 plastic types in 54 product subsegments in Switzerland in 2017 with a recycling rate of 9%. In a prospective material flow analysis of a scenario for 2025, the collection rate of the plastic fractions collected in 2017 is increased to 80%. The secondary material flows are allocated to suitable uptaking product subsegments using a linear optimization. The maximum share of secondary materials utilizable in each product subsegment is estimated, whereby three sub-scenarios involving high, moderate and low allowed secondary material shares are modelled. Depending on plastic type and scenario, 21% to 100% of the secondary material gained can substitute for primary material, covering 11% to 17% of the total material demand. While the overall recycling rate could reach 23%, taking into account only the uptaken secondary materials a true recycling rate of only 17% results in the moderate applicability sub-scenario. Based on these results, the secondary material uptake can be said to constitute a limiting factor for increased future recycling. Therefore, thorough consideration of the possible secondary material application is a prerequisite for designing and assessing future recycling systems or for setting recycling rate targets.

The environmental performance of enhanced metal recovery from dry municipal solid waste incineration bottom ash.

This study assesses the environmental performance of the municipal solid waste (MSW) incineration bottom ash (IBA) treatment plant in Hinwil, Switzerland, a large-scale industrial plant, which also serves as a full-scale laboratory for new technologies and aims at an optimal recovery of metals in terms of quantity and quality. Based on new mass-flow data, we perform a life cycle assessment that includes the recovery of iron, stainless steel, aluminium, copper, lead, silver and gold. Fraction-specific modelling allows for investigating the effect of the metal fraction quality on the subsequent secondary metal production as well as examining further metal recycling potentials in the residual IBA. In addition, the implications on the landfill emissions of IBA residues to water were quantified. The impact assessment considered climate change, eco- and human toxicity and abiotic resource depletion as indicators. Results indicate large environmental savings for every impact category, due to primary metal substitution and reduction of long-term emissions from landfills. Metal product substitution contributes between 75% and >99% to these savings in a base scenario (1'000-year time horizon), depending on the impact category. Reductions in landfill emissions become important only when a much longer time horizon was adopted. The metal-based analysis further illustrates that recovering heavy non-ferrous metals - especially copper and gold - leads to large environmental benefits. Compared to the total net savings of energy recovery (215 kg CO2-eq per tonne of treated waste, average Swiss plant), enhanced metal recovery may save up to 140 kg CO2-eq per tonne of treated waste.

Linking energy scenarios and waste storylines for prospective environmental assessment of waste management systems.

Multiple international and supranational organizations call upon changes in current waste management practices to play a key role in developing more sustainable economies. Life cycle assessment (LCA) is a popular method used to assess the sustainability of future waste management options. The uncertainties about future energy systems and waste compositions, however, may lead to ambiguous LCA results. One way to deal with this challenge is the development of joint energy and waste scenarios to investigate the robustness of waste management options. To date, joint energy and waste scenarios rely on the integration of large economic and engineering models. Complex models can hamper the transparency required for decision-makers to understand and implement LCA recommendations. Here we present the alternative of combining diverse energy scenarios and stakeholder-based waste storylines. This is a more qualitative approach than previous sustainable energy/waste evaluations and has a double aim: to address upfront the energy and waste composition sensitivity and enhance transparency by both relying on well-documented energy scenarios and involving stakeholders in the waste storyline formulation. We apply the approach to the Swiss municipal solid waste (MSW) management system in the context of the energy transition away from nuclear power. Three energy scenarios capture how radical the transition might be, while the storylines reflect societal developments and waste policies leading to low, high, and average MSW amounts. The approach delivers feasibility spaces of energy systems and waste compositions as input to the LCAs. It ensures a high level of transparency, which, in conjunction with the participation of decision-makers, has the potential to increase the chances of implementation of the recommendations based on LCA results.

Life cycle inventories of waste management processes.

To allow for an up-to-date and geographically specific life cycle assessment, updated and regionally specific life cycle inventories are crucial. This data article present up-to-date life cycle inventories of several collection, sorting and recycling processes of municipal solid waste fractions for life cycle assessments of waste management systems. In total, 190 life cycle inventories for processes within municipal solid waste management were either newly developed or adapted from existing datasets. The data for 51 recycling processes has been collected to update existing processes or create new process models. Two modules for biogenic processes were taken from literature and 10 processes were modeled based on the existing ecoinvent processes with minor adjustments [1]. The substitution of 36 materials from recycling processes was modeled. In addition, the thermal treatment of 12 waste fractions was modeled within 84 life cycle inventories compromising the thermal waste treatment and the recovery and recycling of recovered fractions from fly and bottom ash. The assumptions and the modelling of the waste treatment processes are described. All life cycle inventory datasets which were newly created, updated or modified compared to the original dataset are described and provided as Excel table. The data are associated with the research article "Modular Life Cycle Assessment of Municipal Solid Waste Management" [2].

Aproximación a la integración de la huella de carbono y aspectos nutricionales para un consumo sostenible de alimentos / An approach to integrate carbon footprint and nutritional aspects for sustainable food consumption

Fundamentos: El consumo de alimentos influye sobre el calentamiento global. Pero no hay que olvidar que los alimentos son una fuente de nutrientes. Para apoyar un consumo sostenible, se ha desarrollado un indicador que integra la huella de carbono (HC) y el valor nutricional de los alimentos. Métodos: Con el fin de proporcionar una ponderación objetiva, se utilizó la técnica no paramétrica 'Análisis Envolvente de Datos' (DEA) para definir la eficiencia-eco-nutricional (ENE). La ENE, definida como 'rendimiento nutricional/impacto ambiental', varía entre 0 y 1, significando 1 que el menú es eficiente. Se presentan dos modelos DEA: el primero basado en el contenido en macronutrientes, mientras que el segundo considera la ingesta diaria recomendada. Los modelos se probaron en un caso de estudio de 256 menús diarios. Resultados: Ambos modelos mostraron valores de ENE entre 0.42 y 1, lo que supone un potencial de reducción de la HC de hasta un 58%. El modelo 2 es preferible porque se basa en recomendaciones nutricionales. Conclusiones: La ENE permite agregar la HC y los aspectos nutricionales en un valor único para apoyar la toma de decisiones. Se proponen mejoras como la introducción de micronutrientes y otros impactos ambientales (AU)

Background: Food consumption has a large influence on global warming. Although we must not forget that the main role of food is nutrient provision. This study develops an indicator to integrate the carbon footprint (CFP) and nutritional values of diets to facilitate sustainable food consumption. Methods: To provide a non-subjective weighting, the nonparametric technique 'Data Envelopment Analysis' (DEA) was used to define the eco-nutritional-efficiency (ENE). The ENE, defined as the ratio 'nutritional performance/environmental impact', ranges between 0 and 1, with 1 being efficient. Two DEA models are presented: model 1 focuses on the macronutrient content, whereas model 2 takes the recommended daily intake into account. They were tested through a case study consisting of 256 daily menus. Results: The case study showed that the vegetarian lunch was in all efficient menus. Western menus performed the worst due to a high CFP from meat. Both models led to ENEs between 0.42 and 1, therefore showing a potential CFP reduction of up to 58%. Model 2 is preferred because it focuses on nutritional recommendations. Conclusions: The ENE succeeds in aggregating the CFP and nutritional aspects to create a unique value that can support decision-making. Further investigation is needed to include micronutrients and other environmental impacts (AU)

Precious metals and rare earth elements in municipal solid waste--sources and fate in a Swiss incineration plant.

In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are essential for the improvement of resource recovery in the Thermo-Re® process.