Journal of Material Cycles and Waste Management最新文献

Waste separation is a fundamental element of environmental governance, yet debates persist over optimal policy strategies. Drawing on the incentive-value-behavior chain, this study explains how and for whom reward-based versus punishment-based interventions sustain waste separation behavior (WSB). Based on field surveys in China, the results indicate that both rewards and punishments directly affect WSB. Internal perceived value plays a mediating role in the process of rewards and punishments in promoting residents’ WSB. External perceived value only plays a mediating role in the process of reward incentives in promoting residents’ WSB. That is, individuals with strong internal perceived value respond to both rewards and punishments, whereas for those with strong external perceived value, reward incentives are more effective. These findings offer valuable insights for governments seeking to select and design their incentive policies for waste separation.

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Rapid tech advances have boosted smartphone disposal, worsening pollution, and waste. This study employed a questionnaire survey and multiple correspondence analysis to investigate smartphone abandonment and recycling. A total of 1306 valid responses were obtained, revealing differences in abandonment behavior among low-, mid-, and high-priced smartphone users. The impact of consumer behavior, recycling and remanufacturing, and smartphone recycling management on smartphone reuse was discussed. Empirical results indicated that the main reasons for smartphone abandonment were memory issues (47%), functional problems (35%), device malfunctions (32%), and freshness of new models (18%). Low-priced smartphone users were more likely to discard phones due to memory issues and device malfunctions, while high-priced smartphone users tended to discard their phones for functionality upgrades or freshness. Additionally, the proportion of abandonment attributed to relative causes of obsolescence, including functional problems, memory issues, and the freshness of new models, reached 52%, gradually surpassing the 17% attributed to absolute causes of obsolescence, specifically device malfunctions. Therefore, promoting green consumerism, encouraging design upgrades by remanufacturers, and improving e-waste management are essential for better resource utilization and environmental protection.

A large part of the organic fraction of municipal solid waste is composed of organic substances that can be divided and transformed into valuable resources. Composting has been promoted as an environmentally friendly method to solve waste pollution concerns, mostly at the household level, due to the high percentage of organic waste generated in homes. Composting is the process of converting organic matter into organic fertilizers. To produce compost and higher-quality products more efficiently, a complete understanding of the composting process is necessary, including the process parameters, the mechanisms active in the process, and the parameters that affect compost production. Additionally, the design of the composting bin, such as the shape of the bin, crusher, microorganisms, temperature, moisture, C/N ratio, pH, and aeration, must be taken into account. This review article examines the parameters affecting compost production from the point of view of home compost design, to optimize the parameters of the composting process and the factors affecting the geometry of the home composting machine to make it easier to produce and use the home composting machine to convert organic materials into compost, especially in countries that produce a large amount of organic waste.

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The growing demand for renewable energy has intensified research into bioethanol production from lignocellulosic biomass, a sustainable and abundant resource. However, the structural complexity and recalcitrance of lignocellulose require effective pretreatment to enhance enzymatic hydrolysis for bioethanol conversion. To address these challenges, gamma irradiation is emerging as one of the nonconventional pretreatments in addition to microwaves, electron beams, ultrasound, and X-rays, which are often used to break the bonds of lignin, cellulose, and hemicellulose and further degrade cellulose into simple sugars. This study explores the ongoing progress of gamma irradiation technology as an innovative pretreatment method for producing bioethanol. Moreover, the mechanisms and the effect of gamma irradiation on cellulose degradation and the surface morphology of irradiated biomass are also studied. Gamma irradiation integration with conventional pretreatment (e.g., NaOH 4%) on reed stalk biomass may lead to the highest cellulose enzymatic hydrolysis conversion rate, reaching 85.02% at 800 kGy. Compared to other radiation methods, gamma irradiation has more advantages with the deepest penetration and experienced high soluble sugars up to 55% at 2000 kGy from sugarcane bagasse. While gamma irradiation demonstrates considerable promise on the laboratory scale, economic and technical barriers remain for its industrial-scale application. Future research should optimize gamma irradiation parameters, explore hybrid pretreatment strategies, and expand its applicability to diverse biomass resources.

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This study systematically explores intrinsic sulfur transformations in biochar derived from the marine macroalgae Ulva australis at pyrolysis temperatures of 350, 550, and 750 °C and their impact on nickel (Ni) adsorption. Comprehensive analyses (FT-IR, XPS, BET, elemental analysis) demonstrated significant sulfur species transitions from sulfate-dominated at lower temperatures to elemental sulfur, sulfide, and thiophenic sulfur at higher temperatures. These transformations correlate directly with increased carbonization, aromaticity, and specific surface area (SSA), particularly at 750 °C (313.39 m²/g). High-temperature biochar (ULV750) showed superior Ni adsorption capacity (96.8 ± 3.8 mg/g), primarily via precipitation and inner-sphere complexation mechanisms of Ni(OH)₂, supplemented by Ni–S interactions mediated by residual sulfur functionalities. This work uniquely highlights intrinsic sulfur transformations, offering insights for optimizing pyrolysis conditions to utilize naturally sulfur-rich biomass for environmental remediation.

Decentralized community composting presents a viable Techno-economic alternative to centralized industrial systems for managing 100% of the organic fraction of municipal solid waste (MSW) in rural municipalities. This study, conducted in Catalonia, Spain, evaluated a system capable of processing 90 t/y of organic matter under six scenarios, varying by mixing method (manual or mechanized) and the number of compost transfers. Mechanized mixing without transfers emerged as the most efficient approach, reducing processing time by 40% and labor demand by 50%, with annual operating costs of 15,141 €/year—14,325 €/year lower than manual methods. Payback was achieved in 10 years, supported by a canon return of 165–194 €/composter (5–7% discount rates). The resulting compost met Class A standards under Royal Decree 506/2013, ensuring high quality. This model aligns with European regulations, addressing 41% of Europe’s organic waste, while promoting a circular economy through localized waste valorization. Mechanization optimizes resource use, reduces costs, and enhances sustainability, offering a scalable solution for small-to-medium municipalities.

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This study explores the optimization of sludge transportation and treatment pathways within a semi-centralized wastewater treatment system in Metro Manila, Philippines, aiming to minimize greenhouse gas (GHG) emissions. Linear optimization was employed to analyze sludge management alternatives, focusing on transportation, treatment processes, biogas production, energy recovery, and emissions. The study evaluates sludge management scenarios, incorporating environmental impacts such as CO₂, CH₄, and N₂O emissions. Results indicate that centralized sludge treatment facilities equipped with anaerobic digesters and combined heat and power (CHP) systems significantly reduce net GHG emissions, achieving a net sequestration of −67.1 tons CO2e/day. Transportation emissions were found to be negligible compared to treatment processes. North Metro Manila Water Treatment Facility (NWTF)’s integrated sludge treatment facility, designed for energy recovery, presented the most environmentally favorable option, whereas facilities relying simply on flaring biogas without energy recovery demonstrated higher emissions. The disposal emissions also contributed greatly to carbon emissions representing 88.8% of the total system emissions. Key findings suggest that enhancing biogas recovery systems and reducing emissions from combustion processes are critical for further sustainability improvements. This provides an insight that disposal emissions should be highly considered when choosing a method rather than its proximity to the treatment facilities. This study highlights the potential of linear optimization in informing sustainable sludge management strategies aligned with environmental and operational goals. While the study provides valuable insights for sustainable sludge management, it is limited by the exclusion of the wastewater treatment emission from which the sludge was derived from. Emission estimates were also based on assumptions and IPCC emission factors in the absence of primary local data. These findings highlight the role of linear optimization in supporting environmentally sound and operationally efficient decision-making in sludge management.

The goal of this study is to compare the environmental and energy performance of three sludge management scenarios at a wastewater treatment plant in Mexico, using process simulations and life cycle assessment (LCA) to assess energy use, environmental impacts, and costs. The functional unit is one cubic meter of treated influent wastewater, including sludge treatment and disposal. Screw press, thermal drying, and anaerobic digestion (AD) were assessed for energy use and environmental impacts, focusing on global warming potential, terrestrial acidification, freshwater eutrophication, and fossil resource scarcity. The Base Case scenario assumes a 50/50 distribution of wastewater flow between two biological treatment lines (anoxic/oxic and conventional activated sludge), with sludge equally treated by drying and screw pressing. The Best-Case scenario directs all flow to the anoxic/oxic line and treats all sludge through AD with electricity and heat recovery. Compared with the Base Case, the Best-Case scenario reduced energy use by 14%, corresponding to a specific energy savings of 0.04 kWh/m³, and achieved annual cost savings of 35,891 USD. The key challenges included limited data on sludge characteristics and disposal practices in Mexico, which required careful adaptation. LCA was enabled through process simulation, which provided site-specific inventory data despite limited regional reporting.

This manuscript reports an assessment of a cement-based solidification/stabilization approach to immobilize toxic heavy metals contained in sewage sludge from the nickel plating/electroplating industry and mitigate its environmental impact via a safe final disposal as a building material. Different preparation conditions of the cement/sewage sludge materials were evaluated to identify their impact on compressive strength and setting times. The results indicated that the increment in the amount of sewage sludge utilized to obtain cement-based specimens affected their setting times and, particularly, reduced the compressive strengths. The samples obtained with sewage sludge/cement ratios ≤ 0.1 exhibited prolonged setting times and better compressive strength. Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were utilized for the physicochemical characterization of cement/sewage sludge specimens. The presence of mullite and hydrated calcium silicate was confirmed in tested specimens, which appear to play a relevant role for developing the material strength. Leaching tests using cement/sewage sludge specimens confirmed that the release of toxic heavy metals from polluted sewage sludge was minimized significantly for zinc and nickel. These results demonstrated the efficacy of the incorporation of sewage sludge in cement pastes for heavy metal immobilization, which can be a reliable and environmentally friendly strategy to dispose of sewage sludge polluted by toxic species.

This study focused on the extraction and full characterization of cellulose from banana peel waste using optimized chemical methods to obtain high yield and purity. The extraction steps included dewaxing, alkaline treatment, delignification, acid digestion, and bleaching, resulting in a cellulose yield of 72.5%. Fourier transform infrared spectroscopy showed the absence of non-cellulosic materials and peaks characteristic of cellulose. The absorption peak observed by ultraviolet (UV) spectroscopy at a wavelength of 293.889 nm indicates the presence of UV radiation filters. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) tests demonstrated that the obtained cellulose had a primary decomposition temperature of approximately 303.9 °C. X-ray diffraction (XRD) analysis proved that it was crystalline in nature, with a degree of crystallinity of 73.35%. The surface morphology of the cellulose was irregular and fibrillar in shape, as revealed by scanning electron microscopy (SEM) and atomic force microscopy images. Energy-dispersive X-ray (EDX) analysis of cellulose showed good purity, with carbon and oxygen as the main elements. Particle size analysis showed a normal distribution with a mean particle size of 102.287 μm. The detailed characterization of banana peel cellulose (BPC) would further advance the development of environmentally friendly high-performance biocomposites to achieve global sustainability goals.