Journal of Material Cycles and Waste Management最新文献

Spent coffee grounds is considered as one of the most common biomass waste globally. The sources of spent coffee grounds being classified as domestic, commercial and industrial. Currently, landfills are the unsuitable destination for the majority of the produced spent coffee grounds and this permits anaerobic breakdown of spent coffee grounds, which produces and releases strong greenhouse gases as a result. Consequently, a wide range of potential uses for discarded coffee grounds and their by-products are being investigated by researchers worldwide, including biofuels, adsorbent, catalysts, cosmetics, composite materials, feed and many more. Spent coffee grounds are rich in carbohydrates, lipids, proteins and minerals. As a result, research focus is on using it in a variety of applications. The review adopts a whole system to summarize up to date knowledge of different methods of thermal breakdown of spent coffee grounds for producing verities of valuable products. Essential processes under this study included, comparative analysis of various thermal decompositions methods, material’s behavior and characteristics evaluation based on thermal treatment and its respective applications, which have often been overlooked in prior reviews.

This comprehensive review was conducted to identify research trends in material flow analysis (MFA) and policy developments regarding plastic waste. In addition, this review aims to explain the methods used to apply MFA to plastic waste management policies. A systematic literature review (SLR) followed by the PRISMA 2021 guidelines was used for data collection, while bibliometric analysis (BA) and qualitative content analysis (CA) were used for data analysis. As a result, this study found limited data on plastic waste generation and material recovery, a lack of research on specific keywords, such as e-waste and plastic pollution, and gaps in information regarding waste management, especially in developing countries. Based on the policy review, there is also a lack of comprehensive policies at the regional and local levels that specifically address the entire plastic lifecycle and the limited regulation in plastic production compared to plastic consumption. Additionally, there is a major focus on plastic waste leakage, but there is insufficient support from local governments and community participation, particularly in Indonesia. In this study, step-by-step guidance for utilizing MFA was documented, especially on how MFA can be used to assess recycling efficiency, minimize environmental impacts, and identify the best strategies to reduce PET waste leakage to the environment. This study can serve as a reference for identifying gaps in policy development related to managing plastic waste, and as guidance for determining and applying the appropriate integration of MFA methodology and plastic waste interventions.

Plastic bottles and sachets have turned out to be more prevalent in all the countries, specifically in urban regions. Despite the awareness among people regarding the destructive impact of plastic, many organizations and management ignore the fact in most countries. Accra is one such region in Ghana where the population has the practice of burning waste open-wide without safety precautions. Adequate and keen research on the practice and perception of the concerned population would help the government rectify the current plight. Considering this, the current study aims to investigate the management measures of the Accra metropolis using a reverse logistic approach. The study also aims to discuss the major problems faced while adapting a reverse logistic approach. The study adopts a mixed methodology where data for the quantitative research are fetched from 118 respondents, of which 15 are from five selected plastic packaging companies and 3 from Accra metropolitan assembly (AMA). The collected data are analyzed using SPSS and thematic analysis. The statistical result proves that the conservation of natural resources and minimization of national plastic packaging wastes have a major impact on healthier profit and the reuse of old plastic products associated with a reduction in hygiene-related problems and a reduction in waste disposal. Coordination with households and plastic retailers is the critical measure of the reverse logistic approach. The thematic analysis reveals that the financial construction or lack of proper infrastructure and equipment are the major issues in adapting the reverse logistics approach. Further discussions and policy recommendations are provided.

Phosphorus (P) is an irreplaceable and non-renewable resource but faces a foreseeable resource shortage. In this study, nitric acid (HNO₃) was employed to extract P from sludge-incinerated bottom ash and nitrogen–phosphorus (N-P) compound fertilizer was synthesized by adding aqueous ammonia to the P-rich extract. The N-P compound fertilizer was continued to be applied to the cultivation of ryegrass, and the impact on plants and soil was analyzed. The results indicated that the optimal concentration of HNO₃ was 5.0 mol/L and 93.1% of P in sludge-incinerated bottom ash could be recovered in HNO₃ extraction. The N–P compound fertilizer prepared after ammonia neutralization exhibited an amorphous complex composed of various substances. The Ca, Mg, Al, and Fe contents of N-P compound fertilizer were 813, 220, 137, and 25 mg/kg, respectively. N–P compound fertilizer enhanced ryegrass growth; after 20 days of planting, the root, stem, and leaf length were 2.0, 1.3, and 1.4 times that of the control, respectively. N–P compound fertilizer did not lead to heavy metal accumulation in plants and soil deterioration after fertilization. This method can fully recover the P source in sludge-incinerated bottom ash and turn waste into treasure.

Historically the disposal of asbestos-containing wastes (ACW) poses significant environmental and health risks due to the hazardous nature of asbestos fibres. Conventional disposal methods such as landfilling without any prior treatment lack long-term sustainability and safety. In this study, we explore the application of geopolymers as a green binder for the solidification and stabilization (S/S) of asbestos-containing waste (ACW) prior to its final disposal into scientific landfill sites to mitigate environmental and health hazards. Geopolymer–asbestos blocks were developed using class F fly ash and alkaline activators. Compressive strength tests revealed that the geopolymer–asbestos blocks exhibited strengths exceeding 8 MPa, making them suitable for safe disposal in landfill facilities. The ideal asbestos content for achieving substantial compressive strength was found to be between 5 and 15% (w/w). Microstructural analysis confirmed the entrapment of asbestos fibres within the geopolymer matrix, enhancing structural integrity. XRD analysis identified quartz as the major mineral phase, with traces of other minerals. Leaching studies demonstrated effective immobilization of toxic metals, such as chromium and lead, within the geopolymeric structure. The absence of heavy metals in leachate samples indicated the efficiency of geopolymer-based S/S in preventing environmental contamination. This study suggests that geopolymerization offers a promising approach for the environmentally sound disposal of asbestos-containing wastes, providing a viable interim solution until the complete cessation of asbestos use in many countries across the globe.

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Industries generate a lot of solid waste, including polyurethane foam waste from refrigeration, automobile, and construction industries. Most of this waste is incinerated or dumped in landfills, causing harm to the environment and loss of land usage. Natural coarse aggregates used in concrete are expensive and require excavation, which affects the environment. This study replaced coarse aggregate with polyurethane foam in concrete to reduce waste disposal and natural coarse aggregate extraction. The replacements were 0, 10, 20, 30, and 40% by volume of coarse aggregate. Experimental investigations were carried out to evaluate the polyurethane foam concrete fresh properties, hardened properties, water absorption, ultrasonic pulse velocity, and microstructure characterisation. Results showed that concrete compressive strengths exceeded 17 MPa and densities less than 2000 kg/m³ when 30 and 40% of coarse aggregate were replaced by polyurethane foam, which satisfied lightweight concrete criteria. The 10 and 20% coarse aggregate replacements showed compressive strengths greater than 20 MPa, with densities above 2000 kg/m³. In all replacements, the ultrasonic pulse velocity value was more than 3.5 km/s. Moreover, an ecological and economic study showed that PU foam concrete had lower embodied energy, embodied carbon emissions, and cost compared to conventional concrete.

In this paper, refuse derived fuels (RDF) produced on an industrial scale in the State of São Paulo (Brazil) were thoroughly characterized. Textiles, paper/cardboard and plastics represent the highest percentage of RDF composition, with the first two fractions being the main contributors to RDF biomass content, which ranges from 39 to 57 wt% on a dry basis (db). Moisture, volatile matter and ash contents range from 19.5 to 35.8, 65.4 to 79.6 and 14.4 to 29.1 wt% db respectively. Carbon content ranges from 43.2 to 53.5 wt% db. The chlorine content is low (0.2–0.8 wt% db) as well as the mercury content which is less than 0.38 μg/kg (db). The net calorific value ranges from 16.9 to 22.0 MJ/kg (db). RDF meet the classification requirements of European and Brazilian standards. Their characteristics demonstrate their potential as a fuel for various thermochemical processes. The use of RDF is therefore an opportunity for a more circular economy. The use of RDF as an alternative fuel in the cement industry brings both economic and environmental benefits. This study provides valuable information for decision-makers to better understand RDF and plan their use in Brazil.

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The acceleration of urbanization has intensified the strain on sewage treatment systems. Research on reducing, rendering harmless, and resourcefully treating organic solid waste has gained significant attention. This study begins by outlining the current state of sludge treatment in China, followed by a review of advancements in pyrolysis, biological treatment, and gasification technologies. It systematically categorizes, compares, and summarizes influencing factors, and process mechanisms of various technologies. The paper focuses on the distinctive features of different processes, emphasizing the high-value utilization of three-phase products and the optimization of reaction conditions. In addition, it provides insights into enhancing the resource utilization of sludge and solid waste, as well as optimizing treatment technologies. This paper aims to consider the ecological environment and economic benefits of the efficient treatment of solid organic waste. It provides reference for industrial application, and contributes to the building of a resource-saving and environmentally friendly society.

This study presents three models based on urban solid waste collection data from three municipalities in southern Brazil to identify collection patterns. With the support of Knowledge Discovery in Databases and Data Mining techniques and algorithms, historical data on the weight of unloaded waste from collection trucks in transfer stations, collection route data, and socio-demographic and climate data were used to predict the amount of solid waste collected at each point and assess collection patterns. Data were collected, pre-processed, modeled, and analyzed using Linear Regression, Gradient Boosting, and Random Forest algorithms. Our results show that the Gradient Boosting algorithm model performed better: Mean Absolute Error (25.244), Root Mean Square Error (87.667), and Coefficient of Determination (0.642). In this sense, this study contributes in two ways: first, it helps organizational decision-making and improves the collection service provided to the local community. Second, this study collaborates with the scholarly literature reinforcing the potential of data mining for urban solid waste management.

Burnt clay bricks are currently facing environmental issues as a result of the increasing depletion of natural clay resources. Recently, researchers have investigated the possibility of using a variety of wastes to produce clay-based bricks. Considering a similar approach, an experimental study has been conducted using agricultural waste, i.e., rice straw. In the study, the effect of the addition of rice straw in the form of ash on the performance of clay-based bricks has been evaluated by replacing the clay content of the mix with different proportions (2%, 4%, 6%, 8%, and 10% by weight) of ash. Apart from the preliminary characterization of materials, various physical, mechanical, and durability characteristics of ash-based bricks were determined. Advanced characterization techniques such as scanning electron microscopy and X-ray diffraction have also been utilized to identify/validate the effect of ash addition. The results revealed that the addition of 2% and 4% ash showed 22.25% and 43.82% reduction in strength, respectively, satisfying the requirements prescribed in Indian Standards, i.e., IS 3495 and IS 1077: 1992, for first- and second-class clay bricks. In addition, the microstructure assessments also validated the obtained results, suggesting the produced bricks are suitable for various practical applications in construction practices.