Is there an environmentally optimal separate collection rate?

Critical properties of plastic packaging waste for recycling: A case study on non-beverage plastic bottles in an urban MSW system in Austria

The low recycling rate of post-consumer plastic packaging waste (PPW), which is partly due to insufficient separate collection, heterogeneous composition and high levels of contamination, poses a challenge in Austria, where the recycling rate must double in order to meet the target of 55 %. This study analyzes key packaging characteristics of non-beverage plastic bottles influencing recyclability, using Vienna as a case study. Additionally, a net quantity indicator and separate collection rates were calculated. 738 bottles from mixed MSW and 1,159 bottles from separate PPW collection were analyzed. The main polymer's proportion described by the net quantity indicator was higher for bottles from separate collection (69-72 %) than from mixed MSW (58 %), showing that a large share of the foreign materials are residues and dirt, with significantly higher contents in mixed MSW (20 %) than in separate collection (11 %). With a separate collection rate of 19.2 %, the great potential for recycling currently lies in mixed MSW at 4,112 t/yr. Thereof, 46 % is uncolored, 54 % is colored/white and, in terms of material grade, 30 % is food grade. The most common filling volume for PET, PP and HDPE was 0.5 < x ≤ 1.5 L (23-59 %) and the most common decoration technology was label (60-85 %). PET and PP had the highest shares of food-grade bottles (37-46 %), while PP had the highest share of colored bottles (22-31 %). The mechanical recycling potential of bottles depends largely on packaging characteristics, influencing separate collection and also automatic sorting. Harmonized design specifications are therefore crucial for this heterogeneous PPW fraction.

Antibacterial and Antifungal Properties of Electrospun Recycled PET Polymeric Fibers Functionalized with Zinc Oxide Nanoparticles

Currently, to reduce the environmental problems associated with plastic waste, methods are being sought to use this waste as raw materials in different applications, such as fibers. In addition, to improve these materials and provide different properties, nanoparticles (NPs) are incorporated. In the present work, polymeric fibers made of recycled polyethylene terephthalate (r-PET) from post-consumer water bottles, functionalized with 0%, 1.5%, 3% and 6% zinc oxide nanoparticles (ZnO-NPs) in function of r-PET weight, were elaborated to evaluate their antibacterial and antifungal characteristics. The ZnO-NPs were synthesized by the solvothermal method, obtaining particles with a mean diameter of 38.15 nm, while the fibers were obtained by electrospinning with a diameter range between 200-5000 nm. The functionalized fibers were carried out against Escherichia coli and Bacillus subtilis through the agar diffusion method, obtaining the highest inhibition halo at 6% w/w ZnO-NPs, being 26.5 mm and 34.25 mm, respectively. In addition, the same method was used to evaluate the antifungal activity of Penicillium s.p. and Fusarium graminearum, observing antifungal properties due to the presence of nanoparticles in the fibers.

Determination of the composition and properties of PET bottles: Evidence of the empirical approach from Perm, Russia

Efficient collection systems and information about the characteristics and quality of collected secondary plastic waste flows are of fundamental importance for the development of circular economies. In order to assess the effectiveness of the implementation of separate collection systems for plastic packaging, especially polyethylene terephthalate (PET) bottles, characteristic of the collected PET bottles in street mesh containers were studied in the city of Perm, Russia. The share of extraneous fractions was assessed and differentiation was carried out by volume, type of product, label presence, shape, content of solid and liquid impurities and colour. These results indicate that PET composition in different seasons is very similar, despite the assumption that the consumption of PET bottles in the spring and autumn seasons varies. In the mesh containers, up to 34% of the items were foreign objects, considering that only PET bottles should be collected. In each dimensional flow of PET bottles, the proportion of transparent bottles prevailed; it ranged from 31% to 70%. Based on the results of the experiment, almost all PET bottle categories had a standard shape, except packaging for food products and household chemicals, in which 26-27% of PET bottles had a non-standard shape. The results about charactersitic of source-separated PET bottles are fundamental for goal-oriented design and implementation of collection, recycling technologies, secondary separation facilities, the economics of recycling intitatives and reverse vending machines for collecting materials.

The impact of incineration phase-out on municipal solid waste landfilling and life cycle environmental performance: Case study of Madrid, Spain

Reducing the amount of municipal solid waste (MSW) fed to incineration while enhancing source separation and biological treatments is being considered a mean to protect the environment and human health and promote recycling. However, such a strategy can compromises the landfill reduction targets while the associated environmental benefits remain so far unexplored and, in any case, any potential benefit should be evaluated for specific situations. In this study we applied material flow analysis (MFA) and life cycle assessment (LCA) to quantitatively evaluate the potential impact of phasing-out incineration in Madrid, Spain. The current MSW management system was assessed against future scenarios that describe the elimination of incineration as well as the increase of source separation, recycling, composting, and anaerobic digestion. The results revealed that incineration phase-out jeopardizes landfill reduction. However, phasing-out incineration can reduce the impact on acidification, terrestrial and marine eutrophication, photochemical ozone formation, human toxicity cancer effects, and ecotoxicity. The climate impact ranges from irrelevant to largely beneficial depending on how the biogenic carbon is considered. The transition towards a renewable electricity mix and the increase in source separation of biodegradable waste seriously compromise the climate benefits of incineration over landfilling. Overall, actions are required in order to align incineration phase-out with the landfill reduction objective, namely upgrading material recovery facilities to reduce rejects and seeking alternative pathways for the rejects that will always exist.

Dynamic Material Flow Analysis of PET, PE, and PP Flows in Europe: Evaluation of the Potential for Circular Economy

This study evaluates the potential circularity of PET, PE, and PP flows in Europe based on dynamic material flow analysis (MFA), considering product lifetimes, demand growth rates, and quality reductions of recycled plastic (downcycling). The circularity was evaluated on a baseline scenario, representing 2016 conditions, and on prospective scenarios representing key circularity enhancing initiatives, including (i) maintaining constant plastic consumption, (ii) managing waste plastic exports in the EU, (iii) design-for-recycling initiatives, (iv) improved collection, and (v) improved recovery and reprocessing. Low recycling rates (RR, 13-20%) and dependence on virgin plastic, representing 85-90% of the annual plastic demand, were demonstrated after 50 years in the baseline. Limited improvements were related to the individual scenarios, insufficient to meet existing recycling targets. However, by combining initiatives, RRs above 55%, where 75-90% was recycled in a closed loop, were demonstrated. Moreover, 40-65% of the annual demand could potentially be covered by recycled plastic. Maintaining a constant plastic demand over time was crucial in order to reduce the absolute dependence on virgin plastic, which was not reflected by the RR. Thus, focusing strictly on RRs and even whether and to which extent virgin material is substituted, is insufficient for evaluating the transition toward circularity, which cannot be achieved by technology improvements alone-the demand must also be stabilized.

Material efficiency to measure the environmental performance of waste management systems: A case study on PET bottle recycling in Austria, Germany and Serbia

Material efficiency measures, such as recycling rates, are often used to set circular economy targets to achieve higher resource efficiency and lower environmental impact. The aim of this study was to identify material efficiency indicators suitable to reflect the environmental performance of waste and recycling systems using PET bottle waste management in three European countries with diverse waste management structures and recycling performance levels. Material flow analysis and life cycle assessment were performed to assess the material efficiency and environmental impacts of each system as a basis to analyze the relation between these two dimensions. PET bottle waste generation was 5.4 kg/person and year (pa) in Austria in 2013, 6.0 kg/pa in Germany in 2017 and 6.9 kg/pa in Serbia in 2015. Out of this waste flow 41%, 91%, and 11% were directed into PET recyclate in Austria, Germany and Serbia, respectively. For all systems, higher material efficiency translated into lower environmental impact and vice versa. However, linear regression analysis between different material efficiency indicators and environmental impacts showed that indicators targeted at actual recycling, specifically at closed loop, were better suited to reflect environmental performance than input-based indicators. Therefore, whenever data are available, output-based quality-related indicators should be used to measure the material efficiency of waste and resource systems because they correlate best with the goals of increasing resource efficiency and decreasing environmental impacts.

How to meet reuse and preparation for reuse targets? Shape advertising strategies but be aware of "social washing"

Preparation for reuse (PfR) is a fundamental waste management practice that is second only to prevention in the waste hierarchy. The paper, building on advertising literature, investigates how to leverage the pro-social nature of this option for giving products that have become waste a second life. To examine how advertising strategies based on emotional, functional or combined stimuli can be used to increase intention to buy these items, we carried out an experiment on 507 actual visitors a PfR items shop run by a social cooperative in Northern Italy. We found that, depending on consumers' social involvement, both emotional and functional stimuli based on the social impact of preparation for reuse tend to outperform functional stimuli and have a positive impact on brand attitudes by shaping attitudes to advertisements. Purchasing behaviour has a positive impact on attitudes toward the PfR organization and moderates the effect of emotional and combines stimuli on attitudes toward the advertisement. Since emotional stimuli can be freely used by both legitimated and opportunistic companies, the former should seek to preserve their value proposition by making it easier for consumers to recognise actually trustworthy organizations. This is possible combining the use of advertisements with the development of solid customer relationships. To this end, awareness campaigns, closer relationships with stakeholders and third-party verifiable standards and certifications should be considered to reduce the risk of "social washing" in the current second-hand market context.

Economic and environmental consequences of implementing an EU model for collecting and separating wastes system in Lebanon

In this study, we examine the economic and environmental significance associated with the implementation of an EU waste-separated collection scheme in a developing context - Lebanon. Two scenarios, S1 and S2, representing different intensities of source segregation were analysed. In S1, the average source segregation intensity reached 25% and 13% for the Italian test area and Lebanese test area, respectively. In S2, source segregation intensity increased to 48% and 68% for the Italian and Lebanese test areas, respectively. Passing from S1 to S2 increased collection costs significantly, up to 44% with greater increases in the Italian test area where labour cost is higher. In both areas, environmental impacts decreased with greater source segregation intensity. Savings in the climate change impact and stratospheric ozone depletion potential were lower under the Lebanese test area in comparison with the Italian test area. In contrast, savings in freshwater eutrophication and acidification impact were lower for the Italian test area. The increase in the source segregation intensity resulted in maximum savings for the depletion of abiotic resources, 74% to 77% and 79% to 80% in a developing and developed context, respectively.

Characterisation of source-separated, rigid plastic waste and evaluation of recycling initiatives: Effects of product design and source-separation system

Recycling of plastic from household waste (HHW) is crucial in the transition towards a circular plastic economy. Plastic from HHW consists of numerous immiscible polymers, product types and product designs (e.g. colour, polymer separability), which often lead to considerable physical losses during sorting, and low-quality recycled plastic. Consequently, recycling initiatives have been proposed to enhance the quantity and quality of plastic recycling from HHW. To quantify the potential effects of such initiatives, a detailed composition of plastic waste is necessary. The aim was to provide such detailed composition of Danish source-separated rigid plastic waste, including information regarding the polymer of the main product component, product type, polymer design and separability as well as colour. The potential effects on recycled quantity and quality from implementing selected recycling initiatives were quantified and recommendations provided. PET, PE and PP made up >90% of the source-separated plastic and both food- and non-food packaging existed in all three polymers. In total, 10-11% of the plastic was black, and around 44% consisted of multiple polymers, of which one-third was non-separable. Initiatives improving product design for recycling will likely result in increased quantity of recycled plastic. By effectively separating food from non-food packaging, e.g. by introducing two bins in the households or politically aligning polymers and product types (all food packaging in PET and PP, all non-food packaging in PE), 39-63% of the waste could potentially be recycled in a closed loop into food-grade quality packaging. The overall highest benefits were reached by combining initiatives.

Integrating High-Resolution Material Flow Data into the Environmental Assessment of Waste Management System Scenarios: The Case of Plastic Packaging in Austria

The environmental performance of the waste management system of plastic packaging in Austria was assessed using a combination of high-resolution material flows and input-dependent life cycle inventory data. These data were used to evaluate different configurations of the waste management system, reflecting the system structure as it was in 1994 in Austria and still is in some of the new EU member states, as well as a situation achieving the increased circular economy targets to be met by 2030. For the latter, two options, namely single-polymer recycling and mixed-polymer recycling, were investigated. The results showed that the status quo achieves net benefits for 15 out of 16 impact categories evaluated. Regarding the alternative scenarios, for most impact categories these benefits increased with increasing recycling rates, although for four impact categories the highest net benefit was achieved by the status quo. For many impact categories the marginal environmental benefit decreased at higher recycling rates, indicating that there is an environmentally optimal recycling rate below 100%. The results also highlight the importance of high-quality single-polymer plastics recycling from an environmental perspective because utilizing mixed polymer recycling to achieve circular economy targets would result in lower environmental benefits than the status quo.

Modular life cycle assessment of municipal solid waste management

Life cycle assessment (LCA) is commonly applied to examine the environmental performance of waste management systems. The system boundaries are, however, often limited to either one tonne of material or to specific waste treatments and are, therefore, lacking a systems perspective. Here, a framework is proposed to assess complete waste management systems based on actual waste flows, assessed with a detailed material flow analysis (MFA) in a modular MFA/LCA approach. The transformation of the MFA into a product-process-matrix facilitates a direct link between MFA and LCA, therefore allowing for the assessment of variations in flows. To allow for an up-to-date and geographically specific assessment, 190 LCA modules were set up based on primary industrial data and the ecoinvent database. The LCA modules show where there have been improvements in different recycling processes over the past years (e.g. for paper recycling) and highlight that, from an environmental perspective, closed-loop recycling is not always preferable to open-loop recycling. In a case study, the Swiss municipal solid waste management system, of which there is already a detailed MFA, was modeled using the new LCA modules and applying the modular MFA/LCA approach. Five different mass flow distribution scenarios for the Swiss municipal solid waste management system were assessed to show the environmental impact of political measures and to test the sensitivity of the results to key parameters. The results of the case study highlight the importance of the dominant fractions in the overall environmental impacts assessment; while the metal fraction has the highest impact on a per kilogram basis, paper, cardboard, glass and mixed municipal solid waste were found to dominate the environmental impacts of the Swiss waste management system due to their mass. The scenarios also highlight the importance of the energy efficiency of municipal solid waste incineration plants and the credits from material substitution as key variables. In countries with advanced waste management systems such as Switzerland, there is limited improvement potential with further increases in recycling rates. In these cases, the focus of political measures should be laid on (i) the utilization of secondary materials in applications where they replace high-impact primary production, and (ii) an increased recovery of energy in waste-to-energy plants.