Journal of Material Cycles and Waste Management最新文献

This study explores the development of an environmentally friendly binder by integrating locally sourced port sediment from Dunkirk Port with waste paper fly ash (WPFA). The aim is to innovate construction materials with a reduced carbon footprint, without prioritizing high mechanical performance. The sediment was processed to achieve two levels of fineness, namely 10 microns and 2 microns, to increase its reactive potential. The formulation of the eco-binder involved a mixture of 75% port sediment and 25% WPFA. Findings indicate that optimal compressive strengths, reaching 14.8 MPa, were obtained in highly humid environments (> 95% R_H) at a temperature of 50 °C. It was observed that finer sediment particle size (2 microns) contributed to enhanced mechanical properties. Nonetheless, the sediment's pozzolanic activity is somewhat restricted at ambient temperatures, necessitating specific conditions for effective reactions. Environmental safety assessments confirm that the produced eco-binder meets the criteria set forth in the SETRA guidelines for sustainable use in construction. The leaching and release potential of WPFA after the development of the eco-binder was meticulously assessed using the four-phase sequential extraction method recommended by the Reference Bureau of the European Communities Commission (BCR). A marked change was observed in the speciation of trace metal elements, with a predominant transition from the soluble fraction to the carbonate fraction, attributed to the carbonation process. In conclusion, the marine sediment investigated shows promise as a sustainable construction material, provided that controlled temperature and humidity conditions are maintained to attain adequate mechanical strengths.

This article highlights the importance of waste management in Algeria, particularly in Oran, despite legislative initiatives such as Law 01–19 on waste management, control, and disposal, as well as the establishment of the National Waste Agency. Although Executive Decree No. 04–199 introduced the public Eco-Jem system for packaging waste treatment and the implementation of the National Integrated Waste Management and Valorization Strategy by 2035, the efficiency of waste treatment remains a challenge. However, the waste valorization sector lags significantly. Data analysis reveals that out of the 693.5 million tons of waste in 2022, less than 1% undergoes composting, while around 11% is recycled, leaving the majority (88%) unprocessed. Our study underscores the significant missed opportunities from insufficient recycling. Energetic valorization of organic matter could yield an estimated 123.5 MWh/day, and composting could bring gains exceeding 5 million US dollars in 2021–2022. Effective selective sorting is crucial for waste solutions proposed. Moreover, sustainable waste management could create 40,000 direct jobs and over 200,000 indirect ones, highlighting the sector’s transformative potential. Advocating for a 3R-VE approach toward a circular economy, this article promotes innovative practices to rejuvenate waste management, ultimately improving life quality in Oran and Algeria.

Waste management has always been one of the most significant challenges in the municipalities of Iran. Besides the municipalities, there are other stakeholders who have an informal yet determinative role in the urban waste management cycle. Most of the separation of valuable waste from cities and its transfer to informal recycling-processing workshops is carried out by these informal groups. The economy resulting from formal and informal cycles is circulating continuously and consistently, though it has also created problems for cities. This study employs the concepts of Systems Thinking and the Causal Loop Diagrams (CLD) model to better understand the current state of waste management practices in Kerman City. The proposed scenarios are based on creating an activity licensing system for informal collectors and encouraging them to cooperate more closely with the Kerman municipality. In the continuation of the CLD cycle for both scenarios, the relationship between each of the players and variables of the model is analyzed and investigated. The results of the project provide a new complete understanding of the determinative variables in cooperation and competition between official and unofficial stakeholders in the waste management cycle of Kerman City.

The growing use of crushed stone and manufactured sand poses a major challenge to the recycling of their by-product known as crushed stone powder (CSP). To establish an effective recycling method for CSP, the authors conducted a detailed investigation on the setting, strength, and durability of alkali-activated materials (AAMs) with slag (GGBFS) and CSP as precursors, and examined their chemical and microstructural characteristics by X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. Experimental results clarified in detail the performance features and influencing factors of AAM made from a blend of CSP and slag, and indicated that CSP can be utilized as an inactive precursor in a large blending ratio (50–80%) to produce AAMs with high strength and excellent durability. The GGBFS/CSP-based AAMs have high flexural strength, reaching up to 1/5 ~ 1/6 of the compressive strength, surpassing 15.0 MPa. The AAMs using CSP almost retain the crystals from CSP within them, and the presence of CSP particles fragments C-A-S-H gels of polymerization reaction product, making them granular and discontinuous. Compared to the siliceous CSP, the limestone CSP slightly enhanced the strength properties of AAM.

Machine vision technique is gaining popularity in metal scraps recycling process due to the increasing need for automation and the relatively low cost of industrial camera. Relative movement between camera and scraps within camera exposure time will inevitably cause image motion blur and influence the separation accuracy. In this study, a novel deblurring prior for camera-conveyor system was proposed and applied to a metal separation system. Key performance indicators, like trajectory stability, separation distance, and separation accuracy, were analyzed and compared between blurred-case separation and deblurred-case separation. The results indicated that by applying the proposed deblurring algorithm, the Peak Signal-to-Noise Ratio (PSNR) value of all the blurred images increased, the average PSNR value of all the 31 blurred images is 27.71 and that of the deblurred images is 29.51. Objects center coordinates shift shows a significant decrease after the deblurring process. A higher conveyor speed may increase the separation efficiency, but will cause the decrease of separation accuracy and separation purity. The scraps motion trajectory obtained from deblurred cases is much more stable, which implies a stable landing point of scraps, and by applying the proposed deblurring algorithm, the separation accuracy increases from 82.9 to 88.0%, and separation purity increases from 90.7 to 93.6%.

National and local governments implement municipal solid waste classification policies to reduce waste disposal and minimize environmental pollution. Beijing started implementing its classification of municipal solid waste policy in May 2020. This study evaluates the impact of Beijing’s household waste classification policy on carbon emissions during collection, transportation, and treatment. The policy’s introduction reduced the number of trash bins, influenced transportation modes, and altered waste treatment emissions. We found a notable reduction in average net carbon emissions post-policy implementation (2403 kg CO₂eq per metric ton of waste) compared with pre-policy (3584 kg CO₂eq per metric ton of waste). If Beijing reaches its 2025 waste target, these emissions will decrease further to 1760 kg CO₂eq per metric ton of waste. Translating these findings into monetary terms confirms this policy’s environmental and economic efficacy.

Mineral carbonation is one of the known methods for carbon capture, utilization, and storage (CCUS). Slag from the steel industry is studied as a common source of CaCO₃ via mineral carbonation owing to its high Ca content. Despite numerous preliminary studies, the optimal factors governing the mineral carbonation of steelmaking slag, such as extraction and carbonation remain unexplored. In this study, we optimized the factors for Ca extraction and carbonation, as CaCO₃ produced under these optimized factors possesses commercial value due to its high purity. The extraction and carbonation experiments were performed on two types of slag samples, specifically non-magnetic steelmaking and pig iron slag, utilizing the chosen factors for each procedure. NH₄Cl was chosen as the extractant because of its high calcium selectivity and inhibition of gel formation. Precipitates with Ca content ≥ 98% were obtained by extracting and carbonating them. The crystalline form and particle size of CaCO₃ in the precipitates were determined by the pH control. The findings of this study will be used to improve the design of precipitated calcium carbonate (PCC) production processes and increase the economic value of their output.

The increasing environmental consciousness and demands of laws have encouraged researchers to develop new environment friendly materials. A large human population requires humongous amount of agricultural produce due to which there is increase in agricultural wastes. Proper use of these wastages can be utilized using the natural fibers/fillers as reinforcements in composites. The usages of these natural solid agro/food wastes have greater potential and provided better solution to replace conventional materials and plastics for domestic and household appliances. Therefore, this review summarized the potential usages and progress of naturally derived bio-fillers and the development of sustainable composites for practical implementations. The intention of this review article is to give a quick overview of the current situation for utilization of these agro/food wastes in the field of polymer composites. The various challenges and qualities during extraction, fabrications, and manufacturing process of these bio-fillers with composites have been also discussed. The performance of developed composites using agro/food waste derived bio-fillers has been also summarized as per their utilizations for various applications. The limitation of these extracted fillers/fibers and polymer composites have been accounted like chemical composition, water absorption, incompatibility with matrix material, limited mechanical properties with their enhancing mechanisms to overcomes these limitations.

Electric vehicle (EV) batteries have lower environmental impacts than traditional internal combustion engines. However, their disposal poses significant environmental concerns due to the presence of toxic materials. Although safer than lead-acid batteries, nickel metal hydride and lithium-ion batteries still present risks to health and the environment. This study reviews the environmental and social concerns surrounding EV batteries and their waste. It explores the potential threats of these batteries to human health and the environment. It also discusses alternative methods to enhance EV-battery performance, safety, and sustainability, such as hybrid systems of green technologies and innovative recycling processes. Finding alternative materials for EV batteries is crucial to addressing current resource shortage risks and improving EV performance and sustainability. Therefore, the development of efficient and sustainable solutions for the safe handling of retired EV batteries is necessary to ensure carbon neutrality and mitigate environmental and health risks.