Resources Conservation and Recycling最新文献

Developing and transition countries merit more attentions on resource monitoring and circular economy implementation to improve global sustainability. With four Eastern European countries, Bulgaria, Croatia, Poland, and Romania, as cases, we integrated economy-wide and dynamic material flow analysis principles to track multiple material flows and stocks during 1990–2019 and investigate circularity performance and decoupling status throughout all life cycle stages of their entire socioeconomic system. Although the absolute stocks presented different trajectories in these countries, they all have witnessed a progressive growth in per capita stocks, reaching 390 t/cap (Bulgaria), 383 t/cap (Croatia), 239 t/cap (Poland), and 306 t/cap (Romania) in 2019, dominated by minerals. Their material use along all life cycle stages has been identified as being in a strong coupling or a relative decoupling with economic outputs and thus further stock expansion is foreseeable. However, their socioeconomic circularity remained at a low level, ranging from 7 % to 14 %. Such sociometabolic patterns affirm demand-side strategies for manufacturing streams close to service provision are required to reduce resource extraction. Proper waste management systems and policy enforcement are needed to maximize recycling and increase circularity, particularly, in Bulgaria and Romania. We call for more bottom-up studies to improve sectoral resolution, zoom in key life cycle stages, and provide tailored insights towards circular economy implementation in such transition countries.

Phosphorus (P) is an essential agricultural nutrient and its production as mineral P fertilizers from phosphate rock is well established. An alternative method involves recovering P from municipal wastewater treatment plants (WWTP) for reuse as fertilizer. Life cycle analysis (LCA) studies have been conducted to assess the environmental impacts associated with both processes. However, systematic comparisons of mineral and recovered P fertilizer production processes are scarce in the existing literature. In this review, we examine the goals, functional units, impact categories, and system boundaries of peer-reviewed LCAs for mineral P fertilizer production (n = 5), recovered P fertilizer production (n = 14), or both (n = 5). To enhance the overall impact and usefulness of these studies for policymaking, we propose a standardized approach for comparative P process studies, while emphasizing the need for simultaneously assessing the environmental effects of P fertilizer production and P recovery from WWTPs. We recommend including key impact categories that are relevant to both processes, such as eutrophication, acidification, global warming potential, soil and water pollution, resource use, and toxicity. Furthermore, adopting a functional unit of one kilogram of elemental P would facilitate better comparisons between LCAs. We also recommend standardized system boundaries that encompass the key aspects of each process.

Clarifying the spatiotemporal changes and trends of carbon sequestration and oxygen release (CO_total) is crucial for establishing policy objectives aimed at achieving carbon peaking and carbon neutrality. However, extant studies have predominantly focused on carbon sequestration, with limited attention to the concurrent oxygen release resulting from the same ecological processes, particularly on a global scale. Here, we revealed the historical and prospective trajectories of CO_total in global terrestrial ecosystems by coupling multiple methods. Results show that global CO_total mainly increased from 2000 to 2020 and is expected to continue rising in the short term. In parallel, 20.91 % of global regions are anticipated to experience a continued decrease in CO_total in the future, while 11.78 % is projected to shift from shift from increasing to decreasing. Proactive and strategic policy interventions in land use and management are imperative in ameliorating the burgeoning global change quandary.

This work explores resource recovery coupled to seawater desalination in small islands. As small islands depend on seawater desalination for water access, they make an excellent ground for exploring the trade-offs associated to resource recovery, like potential economic gains, energy use, and environmental impacts. Here, we investigated these tensions in the context of Lampedusa, in Italy. We then developed and evaluated scenarios for the recovery of additional water, Mg, and other resources from brines, to identify if and how resource recovery is an interesting approach for the island vis-à-vis these tensions. We have found that the potential to increase water production with water recovery from brine is an interesting alternative for small islands, especially when harnessing waste heat. However, while some technologies offer possibilities for recovering additional resources, in places like small islands the potential benefits from additional recovery do not seem to justify the costs to the local system.

The increasing metal demand driven by energy and digital transition has led to more complex mining operations. To allocate environmental impacts in cases of mining co-production, this study proposes a physical method based on the relative geological scarcity of elements, which provides the basis for an exergy cost allocation. It focuses on calculating the energy and carbon footprint of 51 metals, including 28 co-products, based on available databases. The analysis considers the fuel type, main production stages and the energy footprint of up to 25 chemicals. This study provides new insights into 39 infrequently studied metals. Results show that by using renewable electricity in production, 41 metals can reduce their carbon footprint by up to 50 %. However, key metals such as Fe or Li require additional decarbonization efforts beyond electricity. Only by decarbonizing metal production is possible a renewable infrastructure that can achieve the energy transition goals.

Food waste (FW) contributes to greenhouse gas emissions, burdens waste management systems, worsens food insecurity, and reduces biodiversity. Consequently, upcycling strategies must be refined to efficiently convert FW into valuable products. The utilization of black soldier fly larvae (BSFL) to convert FW into nutrient-rich insect meal for use in poultry diets is one such nascent strategy. This upcycling strategy has the potential to address food security challenges while reducing environmental impacts of both FW and poultry production systems. Indeed, innovations in BSFL production and the abundance of FW means that this strategy has a high potential for adoption and scaling up, despite a regulatory framework that lags in several countries. We analyse the suitability of various FW streams for BSFL and the insect's nutraceutical value for poultry. This strategy can resolve the global FW problem while contributing towards sustainable food production systems with minimal recourse to additional planetary resources.

The environmental benefits of recycling depend on the extent to which it reduces virgin material consumption, yet there currently is a lack of empirical research on this relationship. This study addresses this gap by leveraging data on variation in the regional adoption of curbside recycling programs in North Carolina between 1999 and 2019. It uses difference-in-differences regression methods with two-way fixed effects to compare solid waste generation between similar communities with and without recycling programs. The study finds that during the study period solid waste generation in North Carolina increased by 6–10 % in the presence of curbside recycling, providing empirical evidence of circular economy rebound on the household level. This result suggests that the current focus of recycling programs and other circular economy activities, which is to increase the availability of secondary resources through collection and recycling, should be complemented by efforts to reduce the consumption of primary resources.

Waste classification is an essential part of environmental pollution management in modern society. Object detection is an accurate and efficient way to classify waste, which is conducive to recycling resources. However, due to low object discriminability, existing waste classification models cannot classify waste in low-illumination scenes. A waste classification model, Dark-Waste, is designed to classify wastes in a low-illumination scenario. Firstly, to solve the scarcity of training data, an efficient and low-cost Illumination Conversion method is proposed to generate the low-light image. Secondly, the improved ConvNeXt network is combined with YOLOv5 to accurately and efficiently classify waste. Finally, we validated the model on a self-built dataset in real scenarios. The experimental results show that Dark-Waste achieves the best detection performance in low-illumination scenes. The Dark-Waste provides a new approach to waste management in complex environments and effectively contributes to the sustainable development of the urban ecological environment.

The lack of economic dye-polymer and fiber-fiber separations for blended textiles prevents large-scale textile recycling. We focus on a clean, cost-effective, and destruction-minimized fiber-to-fiber recycling, suitable for polyester/cotton blended textiles. Here, dyed polyester was dissolved and separated from the blend, followed by controllable polyester precipitation to retain its dyes separately in the solution. The remaining-colored cotton was swollen to remove its dyes after cleavage of dye-cellulose bonds. Colorless polyester and cotton were regenerated into fibers with similar and 60 % higher tenacity than those before the recycling, respectively. Recycled fibers also had desirable dyeability, including dye exhaustion and colorfastness, after being dyed with the dyes extracted from the polyester/cotton blends, via our newly developed solvent dyeing system. More than 99 % of the solvent used in the recycling was recycled. Our recycling had a cost and energy consumption of less than 20 % of the production of virgin materials.

USABLE Packaging project has developed an innovative value chain based on mixed microbial cultures using organic wastes as feedstock to produce prototypes of PHA-based items that were compared to their commercial counterparts, so the expected better environmental performance can be checked. To do so, a cradle-to-grave life cycle assessment was carried out. The system was modeled integrating all available knowledge, from pilot-scale data to process simulators, and following upscaling frameworks. PHA-based items outperform their commercial counterparts since they show environmental benefits thanks to the avoided electricity obtained in the cogeneration heat and power unit within the PHA production; however, these environmental benefits are very sensitive to the substituted electricity environmental burdens. The different levels of development and market implementation are seen as critical and therefore attention should be paid on how upscaling affects the results and interpretation of the LCA while serving as a guide for process and product development.