Consumers confused 'Where to dispose biodegradable plastics?': A study of three waste streams.

Biodegradable plastics, either fossil- or biobased, are often promoted due to their biodegradability and acclaimed environmental friendliness. However, as demonstrated by previous literature, considerable confusion exists about the appropriate source separation and waste management of these plastics. Present study investigated this confusion based on manual sorting analyses of waste sampled from packaging waste (P), biowaste (B) and residual waste (R) in an urban area of Austria. The results were evaluated relative to near-infrared sensor-based sorting trials conducted in a German urban area. Although existing literature has focused on waste composition analyses (mostly in stand-alone studies) of the three waste streams, the present study focused on identifying the specific types of biodegradable plastic items found in each of these streams. Supermarket carrier bags (P = 90, B = 14, R = 33) and dustbin bags (P = 2, B = 46, R = 6) were found in all three waste streams in the Austrian urban area. Similarly, in the German urban area dustbin bags (P = 1, B = 106, R = 3) were the common items. The results indicate that certain bioplastic items were present in more than one bin; thus, hinting that consumers are not necessarily aware of how-to source-separate the biodegradable plastics. This suggests that neither consumers nor current waste management systems are fully 'adapted' to bioplastics, and the management of these plastics' waste is currently not optimal.

Rebound effects of food waste prevention: Environmental impacts.

Food waste prevention across the food supply chain has been addressed by the European Union (EU) as the top priority to reduce farm-to-fork impacts. Despite the environmental benefits of food waste prevention are widely acknowledged, life cycle assessments usually do not account for rebound effects, the inclusion of which may decrease or even cancel out the expected environmental savings. Rebound effects are understood as the re-spending of accrued monetary savings, determined by the implementation of food waste prevention initiatives, either on the same product (i.e. direct effects - food) or on other products and/or services (i.e. indirect - non-food) including economy-wide effects (macroeconomic rebound effects). Macroeconomic rebound effects were quantified by means of the global equilibrium model Fidelio and were then converted into environmental impacts by performing an environmentally extended input-output analysis based on the assessment method Environmental Footprint 3.0. From an environmental and an economic perspective, it was found that food waste prevention initiatives across the entire food supply chain were beneficial, but efforts targeting households should be prioritised as the largest potential savings were obtained at this stage. Prevention initiatives implemented at households were associated with potential savings of up to 1 t CO2-eq. t-1, which was reduced to a potential saving of 0.6 t CO2-eq. t-1, corresponding to a 38 % decrease, when accounting for macroeconomic rebound effects. Finally, our results highlighted the importance of accounting for adjustment costs in the production stages of the food supply chain.

Environmental performance of dewatered sewage sludge digestate utilization based on life cycle assessment.

Due to the global trend of urbanization, the amount of sewage water is increasing in cities. This calls for efficient treatment of the resulting sewage sludge. To date, in the 27 European Union member countries (EU-27), the prevailing treatment method is application on arable land. Anaerobic digestion is one of the treatment methods being increasingly used nowadays. However, the resulting digestate requires further utilization. Therefore, in this study, the environmental performance of composting, combustion, and pyrolysis options for dewatered sewage sludge digestate is evaluated based on a life cycle assessment. The results show that digestate combustion and composting performed better than pyrolysis for most of the selected impact categories. However, pyrolysis of sewage sludge is still under development, and there are, to some degree, uncertainties in the data related to this technology; thus, more information for the performance assessment of pyrolysis is still required.

Environmental and Socioeconomic Impacts of Poly(ethylene terephthalate) (PET) Packaging Management Strategies in the EU.

Plastics are a challenge for the circular economy due to their overall low recycling rate and high dependency on primary resources. This study analyzes the EU demand for poly(ethylene terephthalate) (PET) packaging from 2020 to 2030 and quantifies the potential environmental and societal savings by changing the waste management and consumption patterns compared with business-as-usual practices. The results of the life-cycle assessment and life-cycle costing show that a maximum of 38 Mt of CO2-eq and 34 kt of PM2.5-eq could be saved with a more efficient waste management system and a robust secondary material market while also avoiding 8.3 billion EUR2019 in societal costs (cumulative 2020-2030). However, limiting annual PET consumption growth appears to have a similar profound effect on improving the efficiency of waste management systems: 35 Mt of CO2-eq, 31 kt of PM2.5-eq, and 25 billion MEUR2019 societal costs could be saved, simply by keeping EU consumption of PET constant.

A Quantitative Sustainability Assessment of Food Waste Management in the European Union.

In an endeavor to make Europe carbon-neutral, and to foster a circular economy, improving food waste management has been identified by the European Union (EU) as a key factor. In this study, we consider 21 pathways, covering: (i) prevention; (ii) reuse for both human consumption and animal feed; (iii) material recycling as an input into the food and chemical industries; (iv) nutrient recycling; and (v) energy/fuel recovery. To include all types of impact, a sustainability assessment, encompassing environmental, economic, and social pillars, is performed and complemented with societal life cycle costing. The results indicate that after prevention, reuse for human consumption and animal feed is the most preferred option, and, in most cases, nutrient recycling and energy recovery are favored over material recycling for chemical production. While highlighting that the food waste management hierarchy should be supported with quantitative sustainability analyses, the findings also illustrate that biochemical pathways should be improved to be competitive despite the fact that food waste valorization has the potential to satisfy the EU demand for the chemicals investigated. Yet, the results clearly show that the potential benefits of improving emerging technologies would still not eclipse the benefits related to food waste prevention and its redistribution.

A life cycle assessment framework for large-scale changes in material circularity.

Increasing material circularity is high on the agenda of the European Union in order to decouple environmental impacts and economic growth. While life cycle assessment (LCA) is useful for quantifying the associated environmental impacts, consistent LCA modeling of the large-scale changes arising from policy targets addressing material circularity (i.e., recycled content and recycling rate) is challenging. In response to this, we propose an assessment framework addressing key steps in LCA, namely, goal definition, functional unit, baseline versus alternative scenario definition, and modeling of system responses. Regulatory and economic aspects (e.g., trends in consumption patterns, market responses, market saturation, and legislative side-policies affecting waste management) are emphasized as critical for the identification of potential system responses and for supporting regulatory interventions required to reach the intended environmental benefits. The framework is recommended for LCA studies focusing on system-wide consequences where allocation between product life cycles is not relevant; however, the framework can be adapted to include allocation. The application of the framework was illustrated by an example of implementing a policy target for 2025 of 70% recycled content in PET trays in EU27+1. It was demonstrated that neglecting large-scale market responses and saturation lead to an overestimation of the environmental benefits from the policy target and that supplementary initiatives are required to achieve the full benefits at system level.

Process-oriented life cycle assessment modelling in EASETECH.

Life cycle assessment (LCA) modelling of resource-related technologies can be challenging in the context of circular economy, bioeconomy, recycling and integrated waste management, where materials are recirculated within processes and undergo chemical-physical transformations. This implies redefinition of physical flows within the LCA model. Additionally, physical flows may have non-linear responses to changes in model parameters and background processes, involve activities such as extraction of materials and chemical substances, and directly affect emissions. However, these non-linear responses and links between physical flows within technologies are often neglected. In this study, four novel LCA modelling features are provided: i) mixing and/or redefinition of physical flows; ii) substance recirculation within physical flows; iii) integration of physical flows from background processes into foreground processes; and iv) (multi)-conditional sequence flows, while maintaining substance and material balances throughout the system. As an expansion of EASETECH, an existing user-friendly LCA software tool for modelling of environmental technologies, a "process editor" (EASETECH+) allows implementation of these four features into EASETECH. The modelling features are implemented into EASETECH as seven individual processes "modules" and applied in an illustrative case-study focusing on anaerobic digestion of source-segregated organic household waste. The case-study demonstrated that the new modelling approach for physical flows, including recirculation, links between flows from background to foreground processes and conditional flows, considerably affected both results and interpretation of the LCA modelling. The recommendation is that process-oriented LCA modelling as presented here can provide critical new insight into the environmental performance of waste technologies and systems.

An environmental and economic assessment of bioplastic from urban biowaste. The example of polyhydroxyalkanoate.

Bio-based and biodegradable plastics promise considerable reductions in our dependency on fossil fuels and in the environmental impacts of plastic waste. This study quantifies the environmental and economic consequences of diverting municipal food waste and wastewater sewage sludge from traditional management to the biorefinery-based production of polyhydroxyalkanoates (PHA) in five geographical regions. The results show that PHA can outperform fossil polyurethane and PHA from first-generation biomass (sugarcane and maize) with respect to both environmental impacts and societal costs (four times lower impacts and eight times lower costs than polyurethane). To outperform other fossil polymers like low-density polyethylene (LDPE), biorefinery performance should be improved further by more efficient utilization of sodium hypochlorite during PHA extraction, minimization of methane leakage in biogas facilities, upgrading of biogas to biomethane, and more effective handling of the liquid fraction from digestate dewatering.

High-value products from food waste: An environmental and socio-economic assessment.

The use of food waste as feedstock in the manufacture of high-value products is considered a promising avenue for achieving (bio)circular economy goals. The use of residual biomass helps decrease fossil fuel dependency whilst simultaneously reducing the demand for additional biomass resource. Despite the interest in exploiting food waste in high-value product manufacturing, few studies assess the sustainability of such applications. In this study a life cycle assessment, a conventional and a societal life cycle costing were performed to evaluate the impacts of five standalone case studies based on wet animal feed, protein-concentrated animal feed, lactic, polylactic and succinic acid production from food waste. The results showed that animal feed production decreased global warming and socio-economic potential impacts relative to conventional feed products. Biochemical manufacturing incurred higher impacts from both the environmental and the socio-economic perspectives. These technologies are characterised by a low technology readiness level that should be taken into account when interpreting and using the results. Precisely for this reason, extensive uncertainty and sensitivity analyses were performed for each biochemical production technology to establish the hotspots, which were identified in steam and ancillary materials consumption, and feedstock-to-product yield. This suggests where to centre future optimisation and research efforts to achieve sustainable competitive technologies. Through this exercise, the study aims to shed light on the relevance of applying life cycle assessment and costing in the design and early (bio)technology development phases.

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.

Organic waste biorefineries: Looking towards implementation.

The concept of biorefinery expands the possibilities to extract value from organic matter in form of either bespoke crops or organic waste. The viability of biorefinery schemes depends on the recovery of higher-value chemicals with potential for a wide distribution and an untapped marketability. The feasibility of biorefining organic waste is enhanced by the fact that the biorefinery will typically receive a waste management fee for accepting organic waste. The development and implementation of waste biorefinery concepts can open up a wide array of possibilities to shift waste management towards higher sustainability. However, barriers encompassing environmental, technical, economic, logistic, social and legislative aspects need to be overcome. For instance, waste biorefineries are likely to be complex systems due to the variability, heterogeneity and low purity of waste materials as opposed to dedicated biomasses. This article discusses the drivers that can make the biorefinery concept applicable to waste management and the possibilities for its development to full scale. Technological, strategic and market constraints affect the successful implementations of these systems. Fluctuations in waste characteristics, the level of contamination in the organic waste fraction, the proximity of the organic waste resource, the markets for the biorefinery products, the potential for integration with other industrial processes and disposal of final residues are all critical aspects requiring detailed analysis. Furthermore, interventions from policy makers are necessary to foster sustainable bio-based solutions for waste management.

Assessment of tetrabromobisphenol-A (TBBPA) content in plastic waste recovered from WEEE.

Due to the variability of additives and polymer types used in electrical and electronic equipment (EEE), and in accordance with the European Directive 2012/19/EU, an implementation of sound management practices is necessary. This work focuses on assessing the content of tetrabromobisphenol-A (TBBPA) in acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC) and their polymer blends (i.e. PC/ABS). A total of 36 plastic housing samples originating from microwave ovens, electric irons, vacuum cleaners and DVD/CD players were subjected to microwave-assisted-extraction (MAE) and/or ultrasound-assisted-extraction (UAE). Maximum mean concentration values of TBBPA measured in DVD/CD players and vacuum cleaners ranged between 754-1146 µg/kg, and varied per polymer type, as follows: 510-2515 µg/kg in ABS and 55-3109 µg/kg in PP. The results indicated that MAE was more sufficient than UAE in the extraction of TBBPA from ABS. To optimize the UAE procedure, various solvents were tested. Higher amounts of TBBPA were obtained from ABS and PP using a binary mixture of a polar-non-polar solvent, isopropanol:n-hexane (1:1), whereas the sole use of isopropanol exhibited incomplete extraction.

Plastic waste from recycling centres: Characterisation and evaluation of plastic recyclability.

While recycling has been recognised as the preferred plastic waste management solution, little is known about the detailed characteristics of plastic waste and how these may affect its recycling. In this study hard plastic, plastic film and PVC waste collected at three Danish recycling centres were sampled and characterised according to product applications, legislative requirements (quality), expected product life time, polymer types and presence of potential impurities such as coloured plastics, non-plastic materials and multi-polymer products. The obtained information was applied for estimation of overall recycling potentials for selected archetype recycling process chains based on material flow analysis. In addition to providing detailed data for the composition of the plastic waste products, the results showed that impurities represented 28% (wet weight) of the plastic waste, and that about 75% of the plastic waste was characterised as Low Quality applications, indicating some legislative recovery restrictions. By accounting for the level/type of impurities, the overall recycling potential was found to be 52% for hard plastics, 59% for plastic films and 79% for PVC waste. The results showed that while varying according to polymer type, the recyclability of "High Quality" plastic waste was 12-35% higher than "Low Quality" applications. While actual results are representative of Danish conditions, the study demonstrates that detailed characteristics of plastic waste are needed to identify potential challenges to recycling and thereby potentially improving the design (and recovery efficiency) of recycling facilities.

Temporal and geographical patterns of solid waste collected at recycling centres.

Citizens increasingly dispose their waste at household waste recycling centres (HWRC). To enhance the collection of recyclables materials, local authorities and waste management companies invest considerable resources in planning. While the planning of these centres requires a comprehensive understanding of collected solid waste, only limited studies have consistently investigated waste data from HWRC. To fill this knowledge gap, historical data for HWRC from the Greater Copenhagen, Central Zealand, Silkeborg and Djursland in Denmark were analysed with regards to temporal and geographical variation. The results showed the mass of collected waste varies seasonally; this trend was consistently seen during the period 2010-2016. Moreover, the data revealed that the total waste collected was principally driven by the number of visitors. The geometric bar plot and ternary plot depicted an increase in the percentage of recyclable materials, whereas the percentage of incinerated waste decreased during the period 2010-2016. The waste characterisation study indicated that about 7% of small miscellaneous combustible waste was brought in black plastic bag, although these bags were forbidden; the results suggest that the percentage of misplaced recyclable materials could considerably decrease if citizens bring their waste in clear plastic bags.

Combustible waste collected at Danish recycling centres: Characterisation, recycling potentials and contribution to environmental savings.

Europe is currently adapting its waste management strategies towards the increased recycling of waste materials, motivated by ambitious recycling targets. This requires correctly sorting and recovering of all relevant waste flows. In Denmark, a considerable share of residential household waste is collected at recycling centres, 16% of which is sent to energy recovery in the form of "small combustible waste". Although essential in order to enhance the management of household waste, very little information exists on its composition. In this study, 25 tonnes of small combustible waste were sampled from eight Danish recycling centres and classified according to material fraction, application and physical properties. On this basis, the potential contribution to the overall recycling rate was evaluated together with estimation of the potential environmental savings associated with recycling of these fractions. Less than half of the sampled waste comprised combustible materials, whereas recyclable fractions accounted for 47-64%, mainly including textiles, plastics and paper waste. Assuming this composition applicable to the national level, recycling these waste materials collected as small combustibles increased national recycling rates for households by 12%, calculated as waste received at recycling processes. Moreover, the potential climate change savings associated with recycling of Danish household waste increased by 30% compared to the current level. Plastics, textiles and paper were the main contributors to this increase, suggesting that improved sorting practices for these materials should be prioritised. The study demonstrates that detailed compositional data for waste materials has paramount importance when estimating recycling potentials and quantifying the associated environmental benefits.

Resource quality of wood waste: The importance of physical and chemical impurities in wood waste for recycling.

Recycling of post-consumer wood waste into particleboard may be hindered by the presence of physical and chemical impurities in the waste stream, therefore calling for increased attention on the quality of wood waste. However, wood waste comprises several uses/types of wood, along with different levels of contamination. This study provides the detailed sampling and characterisation of wood waste according to its source, type and resource quality grade. Eight tonnes of wood waste, intended for recycling and collected at three Danish recycling centres, were subdivided into 34 individual material fractions and characterised with respect to the presence of three classes of physical impurities (misplacements, interfering materials and low-quality wood waste) as well as chemical concentrations of more than hundred chemical elements and persistent organic pollutants (POPs). The results demonstrated that contaminant and concentration levels vary significantly according to wood waste type and source, thus emphasising that wood waste should not be viewed as a single material flow but rather be understood and managed according to the presence of individual fractions. Including only clean wood waste fractions at the three recycling centres, 41-87% of the collected wood waste per weight could be recycled - the rest being physical impurities. The results showed that chemical contamination was significantly higher for low-quality wood waste, thus clearly indicating that improvements in separate collection, sorting and handling of wood waste may improve the resource quality of wood waste and potentially achieve cleaner recycling practices.

Valorisation of surplus food in the French retail sector: Environmental and economic impacts.

The retail sector, generating large amounts of food waste in a limited and well-defined number of locations, represents a unique opportunity for the implementation of waste minimisation policies targeting food waste and surplus food. France has introduced policy measures forcing retailers to prioritise the redistribution of surplus food to charity (donation) and/or diversion to animal feed. To evaluate the environmental benefits from such initiatives, this study provides a bottom-up consequential life cycle assessment of surplus food management at twenty retail outlets in France. A cradle-to-grave assessment was performed, including land-use changes, and the impacts were evaluated for ten impact categories. Four scenarios were considered, using monthly data on waste flows and management. Alongside assessing the current management (i.e. redistribution and/or use of surplus food for animal feed with anaerobic digestion and incineration of residual streams), three additional scenarios were evaluated: (i) prevention (used as benchmark), (ii) anaerobic digestion and (iii) incineration. The results demonstrated that redistribution leads to substantial environmental savings when accounting for all potentially induced benefits, second only to prevention but nevertheless of similar magnitude. Neither anaerobic digestion nor incineration can compete environmentally with redistribution and use as animal feed, especially in a low-carbon energy system. A cost analysis, including tax credits implemented in the French regulation, demonstrated that retailers donating high-value products also achieved lower costs and higher environmental savings overall. The results clearly suggest that similar initiatives should be encouraged, and the study offers a consistent basis for evaluating similar initiatives also for other countries.

Dynamic accounting of greenhouse gas emissions from cascading utilisation of wood waste.

Cascading utilisation of post-consumer wood waste has recently gained increasing attention in the European Union, aiming for a society in which the resource's properties are optimized through sequential uses. To date, material utilisation of wood waste has been limited to particleboard production, with additional niche alternatives being restricted by quality requirements for wood waste. In this consequential life cycle assessment focusing on post-consumer wood collected at Danish recycling centres, Global Warming Potential (GWP) impacts from quality-driven choices for cascading management of wood waste were compared with those from handling mixed wood waste qualities. GWPs were modelled by considering the dynamic profile of greenhouse gas emissions (including biogenic carbon dioxide) for two time horizons (100 and 500 years). The robustness of the results was tested by varying modelling assumptions with respect to electricity system, wood sourcing and associated rotation period, and impacts from indirect land use changes. The results demonstrated that valuing quality over quantity in wood waste management can ensure larger GWP savings, especially if recycling applications have a long lifetime and/or substitute energy-intensive products; such results were confirmed under all scenario analyses. Inclusion of land use changes credited land-intensive products. More cascade steps of the wood waste resource ensured larger savings; however, assumptions on the electricity mix, on the source of the wood alongside the choice of the time horizon for GWP greatly influenced the results on cascading management.

Environmental impacts of food waste: Learnings and challenges from a case study on UK.

Food waste, particularly when avoidable, incurs loss of resources and considerable environmental impacts due to the multiple processes involved in the life cycle. This study applies a bottom-up life cycle assessment method to quantify the environmental impacts of the avoidable food waste generated by four sectors of the food supply chain in United Kingdom, namely processing, wholesale and retail, food service, and households. The impacts were quantified for ten environmental impact categories, from Global Warming to Water Depletion, including indirect land use change impacts due to demand for land. The Global Warming impact of the avoidable food waste was quantified between 2000 and 3600 kg CO2-eq. t-1. The range reflected the different compositions of the waste in each sector. Prominent contributors to the impact, across all the environmental categories assessed, were land use changes and food production. Food preparation, for households and food service sectors, also provided an important contribution to the Global Warming impacts, while waste management partly mitigated the overall impacts by incurring significant savings when landfilling was replaced with anaerobic digestion and incineration. To further improve these results, it is recommended to focus future efforts on providing improved data regarding the breakdown of specific food products within the mixed waste, indirect land use change effects, and the share of food waste undergoing cooking. Learning from this and previous studies, we highlight the challenges related to modelling and methodological choices. Particularly, food production datasets should be chosen and used carefully, to avoid double counting and overestimation of the final impacts.

Statistical analysis of solid waste composition data: Arithmetic mean, standard deviation and correlation coefficients.

Data for fractional solid waste composition provide relative magnitudes of individual waste fractions, the percentages of which always sum to 100, thereby connecting them intrinsically. Due to this sum constraint, waste composition data represent closed data, and their interpretation and analysis require statistical methods, other than classical statistics that are suitable only for non-constrained data such as absolute values. However, the closed characteristics of waste composition data are often ignored when analysed. The results of this study showed, for example, that unavoidable animal-derived food waste amounted to 2.21±3.12% with a confidence interval of (-4.03; 8.45), which highlights the problem of the biased negative proportions. A Pearson's correlation test, applied to waste fraction generation (kg mass), indicated a positive correlation between avoidable vegetable food waste and plastic packaging. However, correlation tests applied to waste fraction compositions (percentage values) showed a negative association in this regard, thus demonstrating that statistical analyses applied to compositional waste fraction data, without addressing the closed characteristics of these data, have the potential to generate spurious or misleading results. Therefore, ¨compositional data should be transformed adequately prior to any statistical analysis, such as computing mean, standard deviation and correlation coefficients.