Resources Conservation and Recycling最新文献

In the recycling process of e-waste, fires caused by the accidental crushing of batteries are a serious problem. Currently, the presence of batteries in e-waste is estimated based on the experience of the staff involved, which lacks speed and accuracy. To solve this problem, an in-line sorting system that can detect batteries by using a combination of X-ray scanning and deep learning was developed. The novel and unique feature of this system is its three-stage deep learning processing. First, the type of e-waste item is estimated from X-ray transmission images. Second, the batteries are detected by networks pre-trained specifically for the estimated item types. And third, batteries overlooked in the image process are detected by a follow-up network trained by a variety of situations. Through a validation study, it was confirmed that the program achieved high accuracy (0.967 for trained e-waste categories and 0.770 for untrained), surpassing a comparative program with a single deep learning network (0.902 for trained e-waste categories and 0.716 for untrained).

Edible cups have been proposed as a solution to littering and plastic pollution arising from disposal of 500 billion beverage cups each year. We applied life cycle assessment and a littering indicator to benchmark the environmental performance of edible cups against mainstream cup types made from paper, polylactic acid (PLA), polystyrene (PS) and reusable cups made from polypropylene (PP) and steel. Various end-of-life treatment scenarios were analysed. Across most impact categories, edible cups incur the largest burdens, and reusable cups the smallest (if reused at least 54 times). Under default assumptions, per cup use, climate change burdens ranged from 0.004 to 0.1 kg CO₂ equivalent, eutrophication burdens ranged from 6.26 × 10^–6 to 4.21 × 10^–4 kg N, fossil resource depletion burdens ranged from 0.05 to 0.284 MJ and water depletion burdens ranged from 0.002 to 0.437 m³. However, if edible cups are eaten after use and substitute a similar snack then their use could incur negligible environmental impact. Furthermore, edible cups demonstrate low littering potential and thus could play a role in transition towards more sustainable coffee consumption.

The ever-increasing demand of food and feed along with enormous amounts of losses, wastes, and discards from agricultural and food supply chain have caused numerous socioeconomic and sustainability challenges. Many of these agro-industrial by-products and food wastes have low nutritional and economic value. Examples of these types of feedstocks include biofuel co-products (e.g. distiller grains, sugarcane bagasse), agro-industrial processing wastes (e.g. oil seed meal, soybean hulls, sugar beet pulp), crop residues (e.g. wheat straw, corn stover) and fruit and vegetables discards. Using feed grade fungi, yeast, bacteria, and enzymes to process (bioprocess) low-valued feedstocks improves protein quality, degrades lignin and improves utilization of dietary fiber for energy, improves phosphorous digestibility, and reduces anti-nutritional factors (e.g., mycotoxins) to permanently change the composition of the feedstocks and improve their feeding value for livestock, and therefore, achieving a sustainable food supply system with reduced carbon, nitrogen, and phosphorus footprint. The purpose of this paper is to provide a systematic review of the challenges and potential use of current agro-industrial and food wastes as animal feed ingredients using bioprocessing to improve their feeding value. Highlights from three case studies on bioprocessing of corn-distiller grains, oil seed meals, crop/wood residues with fruit and vegetable discards will be discussed relative to changes in feeding value and contributions toward achieving a more circular and sustainable food supply chain.

Humans are surrounded and even dependent on discrete products for their daily activities. Product design processes have been vastly studied towards a healthy economic prosperity and other technical objectives (e.g., low risk). However, recent studies show that these methods have been lacking in terms of the environmental challenges humanity faces in the present and future. This study proposes a novel design framework that incorporates a parametric life cycle assessment (PLCA) as part of the optimization-based design model of a discrete product at early stage. Electric traction motor design applied to an electric vehicle is used as a case study. The results of performing a multi-objective design problem and an uncertainty analysis using Monte Carlo simulation show the usefulness of incorporating the PLCA in a transparent manner, as required by the International Standards Organization. Future work suggests investigating the expansion of this technique to support a broader range of objective functions.

Today's post-consumer plastic recycling is limited by labor-intensive manual quality control (MQC) procedures, resulting in largely unknown pre-concentrate purities. Sensor-based quality control (SBQC) could enable an automated inline quality monitoring and thus contribute to a more transparent and enhanced plastic recycling. Therefore, we investigated the technical feasibility of near-infrared-based SBQC for plastic pre-concentrates in a lightweight packaging waste sorting plant. The developed SBQC method outperformed MQC methods by reducing measurement uncertainties from between ±0.8 wt% and ±6.7 wt% (MQC) to ±0.31 wt% (SBQC) for bale-specific purities at monolayered material flow presentations. In addition, we show that SBQC may even be possible at multilayered material flow presentations, although further research is needed to address identified segregation effects. The demonstrated technical feasibility of SBQC at plant scale represents a major breakthrough as it opens new opportunities in plastic recycling, such as adaptive pricing models and intelligent process control in sorting plants.

Recovery of valuable resources from waste printed circuit boards (WPCBs) is affected by the low recycling rate of discarded WPCBs and their highly heterogeneous material composition. Conventional electronic waste management processes, including incineration and disposal in landfills, generate toxic pollution. Alternatively, the valuable metals contained in WPCBs make “urban mining” of this resource increasingly attractive. Instead of conventional recovery processes that convert valuable metals in WPCBs into pure substances, recent strategies focus on alternative material recovery processes that can directly convert WPCBs into functional value-added materials, such as nanopowders. In this study, recently-developed experimental processes for producing copper-based nano-/superfine powders from WPCBs were reviewed. Six alternative material recovery processes were selected for assessment, including three chemical processes: selective leaching, slurry electrolysis, and microemulsion; two thermal processes: low- and high- temperature thermal processing; and one physical process: mechanical alloying. An alternatives assessments (AA) approach was applied to evaluate functional performance, scale-up potential, and sustainability of each of these material recovery processes. The results from the evaluation of fourteen attributes showed that chemical processes performed better in functional performance but were material intensive. In contrast, thermal and physical processes showed better scale-up potential but were energy intensive. Thus, this study provides a robust assessment to guide future process design before these processes advance into commercial production. Moreover, by incorporating multiple divergent attributes for evaluation, the comprehensive and scientifically rigorous AA framework informs strategies to improve the circular economy of WPCBs by systematically comparing the benefits and potential drawbacks of early-stage alternative material recovery processes.

Lightweight design can contribute to savings of consumed material in products and enhancing their energy efficiency during the use phase but also to a higher resource consumption at the beginning- and the end-of-life, challenging the implementation of a circular economy. Hence, this publication methodologically addresses the synergies and conflicts of lightweight design and design for circularity. The concept of the ‘functional life cycle energy analysis’ is presented, which foresees the division of a product architecture into functions with allocated energy consumptions as cross-stage indicator for the expected resource consumption along the entire product life cycle. Holistic optimization potentials within three life cycle stages can thus be derived as recommendations for action for future product generations. This allows engineers to rethink functional principles and supports decision making in the early design phases of implementing lightweight design and design for circularity. The methodology is illustrated by means of a robotics use case.

This study (1) qualitatively describes sustainable dietary behaviors (SDBs) that Japanese and German adults can implement in their lives, and (2) quantitatively compares similarities and differences in understanding SDBs between the two samples. Data regarding understanding of SDBs from online focus group interviews (16 Japanese, 50.0 % women) and an online open-ended survey (498 Japanese and 197 German, 56.6 % women) in 2021 were analyzed using manifest content analysis and Chi-square and Fisher's exact tests. Consequently, 64 subcategories and 34 categories were identified and grouped into five scenes: food choice, storing and preservation, cooking, eating, and disposal. Of the categories, 16 had significantly different proportions by country (p < 0.05). Many Japanese participants mentioned SDBs related to food waste prevention, while German participants mentioned behaviors related to solving environmental problems more frequently. Our study deepens adults’ understanding of SDBs and contributes to strategy development to improve food sustainability among consumers.

Given the dramatic increase in end-of-life (EoL) photovoltaic (PV) panels, recycling of the EoL PV panels and recovery of valuable resources therein in a sustainable way became a major concern in the industry. In this regard, the feasibility of alternative leaching reagents that can replace the conventional HNO₃ was assessed, and resulting stoichiometries from the experiments were used to construct the inventory for the following life cycle assessment. Under optimized conditions, the efficiency of the alternative systems was comparable (ca. 90%) to the conventional system using HNO₃, while the environmental impacts of which effectively reduced in most categories using the ReCiPe2016 midpoint method. In addition, uncertainties associated with the amount of chemicals and recovered materials were further considered from the Monte Carlo simulation. The resulting impact variances from using the different leaching agents showed meaningful statistical differences (p < 0.05), which corroborates the legitimacy of so-called ‘green leaching’.

Severe climate change and urgent climate action have raised concerns about wood. Overharvesting and increased wood waste are putting immense pressure on sustainable forest management and the global carbon budget. In Germany, a vital wood supplier and user in Europe, the wood supply chain's production, consumption, trade, and recycling have been insufficiently investigated. To tackle this challenge, we conducted a comprehensive dynamic wood flow analysis from 1991 to 2020. Approximately 2143 million cubic meters of standing timber were felled in German forests over the past three decades, with 80% used for materials and 20% for energy purposes. Wood flow patterns were susceptible to market demand and forest disturbances like drought, storms, and insect infestations. The storm in 2007 left a notable impact, leading to the highest figures ever recorded for various wood products. Notably, the net forest carbon sink, carbon storage in forest products, and energy substitution effect (replacing fossil energy with wood) reached 160, 332, and 343 million tons of carbon, respectively. However, the transition to renewable energy, wooden buildings, and wood and paper packaging demands further strains the wood supply chain. To promote sustainable forest management and achieve climate neutrality, we propose potential strategies for consideration.