Global plastic waste recycling and extended producer responsibility laws

Elemental analysis by neutron activation analysis and synchrotron x-ray fluorescence microscopy of ocean plastics ingested by pelagic seabirds

We report the combined use of Neutron Activation Analysis (NAA) for bulk measurement of marine plastics ingested by wildlife, with a more detailed analysis of individual plastics at different stages of degradation using synchrotron X-ray fluorescence microscopy (S-XFM). On average, Sable Shearwaters (n = 9) ingested 4.16 ± 4.62 g of plastics (50 ± 35 items), most of which were high-density polyethylene (47.4 %) and polypropylene (42.6 %) as determined by attenuated total reflectance Fourier transform infrared spectroscopy. Using NAA, the most abundant elements (Ti, Zn, Cd, Cu, Cr, Sr) were those commonly associated with plastic additives that confer UVC resistance, mechanical properties, or colouration. S-XFM revealed that visually and structurally near identical plastics may not only contain different chemical elements, but that the internal spatial distribution of these elements can vary substantially. S-XFM also detected the presence of lead (Pb) which may indicate prior recycling history of the plastic feed stock. A consistent finding was the accumulation of iron (Fe) and bromine (Br) at the surface of the degrading plastics, attributable to biofilm formation. Our observations highlight that bird populations ingesting marine plastics are exposed to an unpredictable profile of chemical elements, the degradation-dependent release rate of which is unknown in the acidic and enzymatically-active stomach environment. Based on the variability of their elemental content, we propose to regard marine plastics as 'mixed waste'. We speculate that plastics more generally could be doped with complex elemental 'fingerprints' for the purpose of traceability and establishment of an unbroken chain of custody.

Aligning national waste management targets with local context: An LCA-based framework for greenhouse gas mitigation-Insights from a case study in China

Municipal solid waste (MSW) management significantly impacts urban climate change. National waste management targets usually guide the general advancement in treatment system but lack alignment with local reality. This study examines the greenhouse gas (GHG) mitigation potential of MSW management in Shenzhen, China, over a 5-15 years period comparing the complete incineration strategy to other policy combinations. Using a life cycle assessment (LCA) based framework, the study integrates waste generation, source separation, and treatment structure into segmental targets, revealing the internal dynamics that influence GHG emissions within waste configurations. Both short-term and long-term implementation effects are provided in terms of GHG mitigation potential to facilitate the effective design of future strategies. Results suggest that shifting from landfilling to complete incineration reduces short-term GHG emissions because of enhanced energy recovery. However, considering the long-term horizon, food waste separation and transitions in energy structure suggest that retaining some landfilling, alongside prioritizing incineration without further expansion, could mitigate up to 3.3 million tons of GHG emissions. Sensitivity of GHG emissions to waste composition and energy structure grows with time, demonstrating the need for adaptable, locally tailored targets to facilitate smooth transition towards long-term sustainability. Given that a one-size-fits-all approach is insufficient, local governments must consider both immediate and future impacts, as well as environmental trade-offs, alongside adopting national goals to develop effective MSW management strategies towards circular economy.

Impact of manufacturers' eco-design decisions on the closed-loop supply chain under recycling rate regulations

To address increasingly severe environmental issues, various countries have introduced relevant environmental protection regulations. This paper proposes a new government regulation measure to encourage manufacturers to improve recycling rates. Governments set recycling rate targets and reward-penalty mechanisms. This paper constructs a game model involving a manufacturer and a remanufacturer within a closed-loop supply chain system. It studies the equilibrium decisions in three scenarios: no government intervention, manufacturers not taking improvement measures despite government-set recycling rate targets, and manufacturers adopting ecological design after such targets are established. Results indicate that after governments establish recycling rate target: (1) After manufacturers adopt ecological design, the prices of new and remanufactured products decrease, sales volume increases, and the profits of both manufacturers and remanufacturers rise. Therefore, manufacturers would be well-advised to adopt eco-design strategies to enhance the level of recycling. (2) As the recycling rate target increase, the level of ecological design decreases, and the prices of new and remanufactured products rise. It is recommended that governments initially set lower recycling rate targets and then gradually increase them. (3) With the increase in the reward-penalty coefficient, the level of ecological design rises, and the price of new products first increases and then decreases. When remanufacturing is unrestricted, the prices of remanufactured products decrease; however, when remanufacturing is restricted, the prices of remanufactured products first increase and then decrease. Therefore, governments would be well-advised to establish a relatively high reward-penalty coefficient.

Enhancing the Efficiency of Plastic Recovery Facilities: Systematically Integrating Seasonal and Regional Variations of Municipal Solid Recyclable Waste Through Infeed Management

Plastic Recovery Facilities are typically designed to process a specific, predetermined mix of plastic in the infeed. However, in many cases, the composition of the infeed varies seasonally and regionally. These variations may result in bottlenecks within sorting machines, thereby causing inconsistencies in the quality and quantity of recovered material. While most recovery facilities attempt to mix different bales before feeding them into the sorting line, relying on trial and error based on the material compositions of those bales, there is a lack of a systematic approach to this process. This paper introduces a systematic approach to plastic sorting within a plastic recovery facility, where the entire recovery process flow is dynamically modelled and validated. By identifying bottleneck regions within the system, infeed bales can be premixed to achieve the designed proportions, ensuring that machines and process lines are optimised for maximum efficiency. A pre-waste survey is necessary to achieve premixing, and the cost is justified by the benefits of the final return. To enhance the efficiency, it is crucial to implement a dynamic mixing model adaptable to daily variations in infeed. In this study, the dynamic optimisation model is designed in the form of simple mixing charts, allowing for on-site premix adjustments to bales without the need for additional equipment or tools. The proposed design chart based mixing methodology can be adopted across the globe to increase the output of established plastic recovery facilities.

Fluvial flooding and plastic pollution - The delivery of potential human pathogenic bacteria into agricultural fields

The frequency of plastic debris entering agricultural land is likely going to increase due to increased discharge into surface waters and more frequent flood events. Microbial biofilm on the surfaces of plastic pollution (known as the 'plastisphere') in freshwater environments often includes human pathogenic bacteria capable of causing disease. Pathogens have been detected on the surface of plastics in freshwater environments, but it is yet to be determined whether plastic debris can also transport pathogens into agricultural fields during flooding. Therefore, this study quantified the presence of viable pathogenic bacteria on the surface of plastic pollution at five agricultural fields along two rivers. All visible plastic debris, including sewage-associated plastic waste, were collected along a perpendicular 100 m transect from the riparian zone into each field. All plastic pieces were screened for five target bacteria (Escherichia coli, intestinal enterococci, Salmonella spp., Campylobacter spp., and Klebsiella spp.) using selective media, and positively identified colonies subsequently tested for antimicrobial resistance. In all five fields, there were higher volumes of plastic in the areas closer to the river, with 75% ± 24% of plastic collected within 30 m from the riverbank. Overall, 49% of all plastic collected in agricultural fields was colonised by phenotypically positive colonies for at least one or more target bacteria, with resistance to commonly prescribed antibiotics detected among several of these target bacteria. Therefore, the transport of contaminated plastic debris from fluvial floodwater into agricultural fields could pose an as yet unquantified risk of introducing potentially harmful bacteria into agricultural systems and the ultimately into the food chain.

Polyethylene packaging and alternative materials in the United States: A life cycle assessment

A comprehensive life cycle assessment was conducted to evaluate the potential environmental impacts of polyethylene (PE) packaging and its alternatives, including paper, glass, aluminum, and steel in the United States. The assessment focuses on five major packaging applications: collation shrink films, stretch films for pallet wraps, heavy-duty sacks, non-food bottles, and flexible food pouches. The study compares PE and the alternative packaging materials based on the following environmental impact categories: global warming potential (GWP), fossil energy use, mineral resource use, and water scarcity. The research integrates sales volume estimates for each application, examining the substitution ratios of PE-based materials and the GWP decrease capabilities of using PE as packaging material. The findings reveal that substituting PE for other packaging materials can lead to an average life cycle GWP emissions decrease of approximately 70 %. This significant decrease highlights the potential GWP benefits of PE in the context of packaging solutions in the United States. We also provide a detailed analysis of the potential environmental impacts and trade-offs associated with PE and its alternatives. The insights gained from this study are intended to assist stakeholders and policymakers in making informed decisions that balance environmental impact mitigation with maintaining product functionality and achieving sustainability objectives.

Integrating the quintuple helix approach into atmospheric microplastics management policies for planetary health preservation

Microplastic pollution has become a major global environmental issue, negatively impacting terrestrial and aquatic ecosystems as well as human health. Tackling this complex problem necessitates a multidisciplinary approach and collaboration among diverse stakeholders. Within this context, the Quintuple Helix framework, which highlights the involvement of academia, government, industry, civil society, and the environment, provides a comprehensive and inclusive perspective for formulating effective policies to manage atmospheric microplastics. This paper discusses each helix's roles, challenges, and opportunities and proposes strategies for collaboration and knowledge exchange among them. Furthermore, the paper highlights the importance of interdisciplinary research, innovative technologies, public awareness campaigns, regulatory frameworks, and corporate responsibility in achieving sustainable and resilient microplastic management policies. The Quintuple Helix approach can mitigate microplastics, safeguard ecosystems, and preserve planetary health by fostering collaboration and coordination among diverse stakeholders.

The time for ambitious action is now: Science-based recommendations for plastic chemicals to inform an effective global plastic treaty

The ubiquitous and global ecological footprint arising from the rapidly increasing rates of plastic production, use, and release into the environment is an important modern environmental issue. Of increasing concern are the risks associated with at least 16,000 chemicals present in plastics, some of which are known to be toxic, and which may leach out both during use and once exposed to environmental conditions, leading to environmental and human exposure. In response, the United Nations member states agreed to establish an international legally binding instrument on plastic pollution, the global plastics treaty. The resolution acknowledges that the treaty should prevent plastic pollution and its related impacts, that effective prevention requires consideration of the transboundary nature of plastic production, use and pollution, and that the full life cycle of plastics must be addressed. As a group of scientific experts and members of the Scientists' Coalition for an Effective Plastics Treaty, we concur that there are six essential "pillars" necessary to truly reduce plastic pollution and allow for chemical detoxification across the full life cycle of plastics. These include a plastic chemical reduction and simplification, safe and sustainable design of plastic chemicals, incentives for change, holistic approaches for alternatives, just transition and equitable interventions, and centering human rights. There is a critical need for scientifically informed and globally harmonized information, transparency, and traceability criteria to protect the environment and public health. The right to a clean, healthy, and sustainable environment must be upheld, and thus it is crucial that scientists, industry, and policy makers work in concert to create a future free from hazardous plastic contamination.

The significance of biowaste drying analysis as a key pre-treatment for transforming it into a sustainable biomass feedstock

The objective of this study is to investigate the drying kinetics of fruit and vegetable peel biowaste using a sustainable technique as a key-pretreatment for its conversion into useful feedstock. Biowaste represents a missed potential source of bioenergy and bioproducts, but moisture removal is required, and conventional drying methods are expensive since they require great quantity of energy supplied, almost always, by a non-renewable energy. In this study six batches with the same quantity of biowaste, and heterogeneous physical composition were dried under open-sun conditions. We evaluated the influence of the interaction between drying area and the initial moisture content on drying rate. Eight semi-theoretical models were fitted using Levenberg-Marquardt algorithm to predict drying rate, and their accuracy was assessed through goodness-of-fit tests. Maximum moisture content to preserve biomass (10%) was reached on 5th day and the equilibrium on 16th day of drying. According to goodness-of-fit test (R 2 = 0.999, χ 2 = 4.666 × 10-5, RMSE = 0.00683) the best model to predict drying rate was Two-term model. The mathematical model obtained from Fick's second law is reliable to predict drying kinetics, R2 (0.9648 ± 0.0106); despite the variation between drying area and initial moisture content. Kruskal-Wallis test showed that drying rates between batches are not significantly different (p = 0.639; 0.05); nor effective diffusion coefficient (D eff  = 4.97 × 10-11  ±  0.3491 × 10-11), (p = 0.723; 0.05). The study of drying kinetics is crucial for selecting the optimal biowaste treatment based on its generation context. This could enable its use as feedstock for bioproduct or bioenergy production, thereby reducing waste accumulation in landfills and environmental impact.

Preparation of 97% pure nickel-cobalt alloy from waste Ni-MH batteries by using waste glass as a fluxing agent

With the e-waste growing rapidly all over the globe due to growing demand of electronics, smartphones, etc., coming up with an efficient and sustainable recycling process is the need of the hour. The present work reports a novel and sustainable process of manufacturing Ni alloy by bringing together three major waste streams such as waste Ni-MH batteries, e-waste plastics, and waste glass. The chosen temperature (1550 °C) favours the reduction of nickel-oxide by e-waste plastic as the reductant and sends rare earth elements present in the waste Ni-MH battery as oxide mixture to the slag phase. Waste glass powder used in this process functions as the fluxing agent, hence not requiring any additional flux. The reduction mechanism is gas-based, controlled mainly by hydrogen and carbon monoxide gases released as a result of decomposition of e-waste plastic as reaction commenced from cold zone (∼300 °C) to hot zone (1550 °C) in the horizontal tubular furnace. Formation of nickel alloy and enrichment of slag with mixture of rare earth oxides were confirmed by XRD, SEM-EDS, and Rietveld refining analysis performed on the XRD spectra of slag phase. ICP-OES (Inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectrometer KT-100S) confirmed the high metal content in the alloy, thereby emphasizing the purity (∼98%) which is close to the composition of nickel super alloy. A maximum of 61% by weight REO enrichment was achieved in the slag phase, having La2O3:44.6%, Pr2O3:14.8%, and Nd2O3: 1.6% under optimised experimental conditions (1550 °C, 15 min, and 20% waste glass powder). This scientific investigation evinces a promising route for efficient utilisation of waste streams emanating from e-waste, thereby devising a sustainable recycling technique and protecting the environment, too.

Progress and Challenges in Polystyrene Recycling and Upcycling

Polystyrene is a staple plastic in the packaging and insulation market. Despite its good recyclability, the willingness of PS recycling remains low, largely due to the high recycling cost and limited profitability. This review examines the research progresses, gaps, and challenges in areas that affect the recycling costs, including but not limited to logistics, packaging design, and policymaking. We critically evaluate the recent developments in upcycling strategies, and we particularly focus on tandem and hydrogen-atom transfer (HAT) upcycling strategies. We conclude that future upcycling studies should focus on not only reaction chemistry and mechanisms but also economic viability of the processes. The goal of this review is to stimulate the development of innovative recycling strategies with low recycling costs and high economic output values. We hope to stimulate the economic and technological momentum of PS recycling towards a sustainable and circular economy.

Characterisation of household single-use packaging flows through a municipal waste system: A material flow analysis for New South Wales, Australia

Household single-use packaging has poor rates of recycling, and presents a challenge in transitioning to a circular packaging economy. This study characterises the flows of household single-use packaging in the municipal waste system for 2020-21 in New South Wales, Australia. Households are an important source of packaging usage in Australia, accounting for over 40 % of all packaging used in 2020-21. Our focus spans 17 single-use packaging materials and 11 formats. We estimate the composition of single-use consumer packaging in the kerbside collection stream, and the ultimate fate of used packaging. Results show 1000 ± 8 % kt of packaging was used by households in NSW in 2020-21 (∼123 kg/cap). Composition of the used packaging stream was dominated by glass (36 %), paper (29 %) and plastic (28 %) packaging. HDPE (26 % of plastic packaging), LDPE (24 %) and PET (19 %) were the main polymers in use. 63 % ± 5 % of used packaging was collected for recycling, and 34 % ± 7 % was recovered via recyclate generation and overseas exports. Glass packaging had the highest recycling rates at 52 % ± 3 %, while plastic packaging had the poorest at 11 % ± 10 %. Findings indicate incorrect disposal of recyclables at the household to mixed-waste systems as a major limitation of the system to improve recycling rates. Expansion in recovery capacity is also essential for improving recycling rates, and the potential for generating the packaging-grade recyclate essential for meeting recycled content targets. The study offers contributions to the understanding of consumer packaging managed within the municipal waste system. Insights gained have application in informing sustainable packaging and waste management strategies.

Exploring the Future of Polyhydroxyalkanoate Composites with Organic Fillers: A Review of Challenges and Opportunities

Biopolymers from renewable materials are promising alternatives to the traditional petroleum-based plastics used today, although they face limitations in terms of performance and processability. Natural fillers have been identified as a strategic route to create sustainable composites, and natural fillers in the form of waste by-products have received particular attention. Consequently, the primary focus of this article is to offer a broad overview of recent breakthroughs in environmentally friendly Polhydroxyalkanoate (PHA) polymers and their composites. PHAs are aliphatic polyesters obtained by bacterial fermentation of sugars and fatty acids and are considered to play a key role in addressing sustainability challenges to replace traditional plastics in various industrial sectors. Moreover, the article examines the potential of biodegradable polymers and polymer composites, with a specific emphasis on natural composite materials, current trends, and future market prospects. Increased environmental concerns are driving discussions on the importance of integrating biodegradable materials with natural fillers in our daily use, emphasizing the need for clear frameworks and economic incentives to support the use of these materials. Finally, it highlights the indispensable need for ongoing research and development efforts to address environmental challenges in the polymer sector, reflecting a growing interest in sustainable materials across all industries.

A review on bio-based polymer polylactic acid potential on sustainable food packaging

Poly(lactic acid) (PLA) stands as a compelling alternative to conventional plastic-based packaging, signifying a notable shift toward sustainable material utilization. This comprehensive analysis illuminates the manifold applications of PLA composites within the realm of the food industry, emphasizing its pivotal role in food packaging and preservation. Noteworthy attributes of PLA composites with phenolic active compounds (phenolic acid and aldehyde, terpenes, carotenoid, and so on) include robust antimicrobial and antioxidant properties, significantly enhancing its capability to bolster adherence to stringent food safety standards. The incorporation of microbial and synthetic biopolymers, polysaccharides, oligosaccharides, oils, proteins and peptides to PLA in packaging solutions arises from its inherent non-toxicity and outstanding mechanical as well as thermal resilience. Functioning as a proficient film producer, PLA constructs an ideal preservation environment by merging optical and permeability traits. Esteemed as a pioneer in environmentally mindful packaging, PLA diminishes ecological footprints owing to its innate biodegradability. Primarily, the adoption of PLA extends the shelf life of products and encourages an eco-centric approach, marking a significant stride toward the food industry's embrace of sustainable packaging methodologies.

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A life cycle assessment of the laboratory-scale oxidative liquefaction as the chemical recycling method of the end-of-life wind turbine blades

According to the latest reports, estimated values of 50,000-66 000 t of end-of-life wind turbine blades (WTB) are expected to be decommissioned in Europe in 2025-2030, posing a significant threat from the environmental and waste management perspectives. This study aims to present the preliminary Life Cycle Assessment (LCA) with sensitivity and uncertainty analysis of the lab-scale oxidative liquefaction process of the WTB, as the original method to recover the high-quality glass fibers with simultaneous production of the secondary chemicals: phenols, ketones, acids, and fatty acids, from the oxidation of the epoxy resin from the polymer matrix. The LCA is based on the experimental results of the oxidative liquefaction process carried out on a laboratory scale using a Parr 500 ml batch reactor, at two different conditions sets for the functional unit (FU) of 1 kg of treated WTB. Each of the analyzed scenarios resulted in higher impact indicators compared to the landfilling. The highest quality fibers were obtained at 350 °C and 40 wt % H2O2 content resulted in 5.52 ± 1.20 kgCO2 eq Climate change impact and 97.8 ± 20.6 MJ of Resource use, fossil per kg of recycled WTB. The lowest quality fiber recovered in char, yet well separated from the matrix obtained at 250 °C and the lowest H2O2 content resulted in 0.0953 ± 0.487 kgCO2 eq Climate change impact and 8.84 ± 7.90 MJ of Resource use, fossil per kg of recycled WTB. The hot spot and sensitivity analysis indicated, that the oxidizer for the process - hydrogen peroxide, when acquired as a shelf product causes a significant burden on the whole process, with sensitivity ratios on the total impact indicators varying across the categories from 0.56 to 0.99. Substitution of H2O2 with theoretical 0-input oxidizer allowed to significantly lower environmental load of the recycling process, which in all of the analyzed scenarios presented environmental benefits compared to landfilling with recovery of the glass fiber and secondary chemicals.

Microplastics in three types of human arteries detected by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS)

Microplastics are ubiquitous in the environment. Human body can be exposed to microplastics through inhalation and ingestion and some microplastics can enter the blood and accumulate in various tissues and organs throughout the body. Animal experiments have suggested that microplastics may promote atherosclerosis. However, data on microplastics in human arteries and clinical evidence supporting a link between microplastics and atherosclerosis are currently lacking. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used in this study to detect microplastics in three types of human arteries: coronary and carotid arteries with atherosclerotic plaques, as well as the aorta without plaques. Microplastics were detected in all 17 arterial samples, with an average concentration of 118.66 ± 53.87 μg/g tissue. Four types of microplastics were identified: polyethylene terephthalate (PET, 73.70%), polyamide-66 (PA-66, 15.54%), polyvinyl chloride (PVC, 9.69%), and polyethylene (PE, 1.07%). Most importantly, the concentration of microplastics in arteries containing atherosclerotic plaques, both coronary arteries (156.50 ± 42.14 vs. 76.26 ± 14.86 μg/g tissue, P = 0.039), and carotid arteries (133.37 ± 60.52 vs. 76.26 ± 14.86 μg/g tissue, P = 0.015), was significantly higher than that in aortas which did not contain atherosclerotic plaques, suggesting that microplastics might be associated with atherosclerosis in humans. This study provides valuable data for further hazard assessments of microplastics on human cardiovascular health.

Characterization of Poly(3-hydroxybutyrate) (P3HB) from Alternative, Scalable (Waste) Feedstocks

Bioplastics hold significant promise in replacing conventional plastic materials, linked to various serious issues such as fossil resource consumption, microplastic formation, non-degradability, and limited end-of-life options. Among bioplastics, polyhydroxyalkanoates (PHA) emerge as an intriguing class, with poly(3-hydroxybutyrate) (P3HB) being the most utilized. The extensive application of P3HB encounters a challenge due to its high production costs, prompting the investigation of sustainable alternatives, including the utilization of waste and new production routes involving CO2 and CH4. This study provides a valuable comparison of two P3HBs synthesized through distinct routes: one via cyanobacteria (Synechocystis sp. PCC 6714) for photoautotrophic production and the other via methanotrophic bacteria (Methylocystis sp. GB 25) for chemoautotrophic growth. This research evaluates the thermal and mechanical properties, including the aging effect over 21 days, demonstrating that both P3HBs are comparable, exhibiting physical properties similar to standard P3HBs. The results highlight the promising potential of P3HBs obtained through alternative routes as biomaterials, thereby contributing to the transition toward more sustainable alternatives to fossil polymers.