Search Results (532)

The transition toward a circular economy (CE) is progressively recognized as a strategic pathway to reconcile economic growth with environmental sustainability. Municipal solid waste management in Jordan remains mostly linear, with over 90% of the generated waste disposed of in landfills and open dumpsites. This study critically examines the prospects of adopting CE principles in Jordan’s waste sector by evaluating current practices, policy frameworks, and potential recycling pathways. A mixed-methods approach was adopted, combining quantitative modeling with qualitative insights from stakeholders and public surveys. Three recycling scenarios were assessed against the baseline scenario: 25%, 50%, and 75% waste recovery by 2034. The U.S. EPA WARM model was used to estimate greenhouse gas (GHG) emissions and energy savings. It was inferred that the net avoided emissions (against the baseline) for Scenarios 1, 2, and 3 are 14.5%, 29.0%, and 44%, respectively, with paper/cardboard contributing most to avoided emissions. Nonetheless, only Scenarios 2 and 3 were deemed environmentally sustainable, as their projected net GHG emissions for 2034 were lower than those recorded in the base year. Socio-economic analysis identified the major barriers as limited public awareness and participation, infrastructural gaps, and financial and institutional constraints. The analysis further reveals that despite the relatively high capital and operating costs associated with advancing toward CE in waste management, the long-term environmental and socio-economic gains are expected to outweigh the associated costs, particularly in terms of avoided GHG emissions and reduced landfill dependency. Full article

Landfills serve as a primary disposal method for municipal solid waste in China, with over 20,000 operational sites nationwide; however, long-term operations risk leachate leakage and groundwater contamination. Amid intensifying climate change and human activities, understanding contaminant evolution mechanisms in landfills has become critically urgent. Focusing on a representative plain-based landfill in North China, this study integrated field investigations and groundwater monitoring to establish a monthly coupled groundwater flow–solute transport model (using MODFLOW and MT3DMS codes) based on site-specific hydrogeological boundaries and multi-year monitoring data, analyzing spatiotemporal plume evolution under the coupled impacts of precipitation variability (climate change) and intensive groundwater extraction (human activities), spanning the historical period (2021–2024) and future projections (2025–2040). Historical simulations demonstrated robust model performance with satisfactory calibration against observed water levels and chloride concentrations, revealing that the current contamination plume exhibits a distinct distribution beneath the site. Future projections indicate nonlinear concentration increases: in the plume core zone, concentrations rise with precipitation, whereas at the advancing front, concentrations escalate with extraction intensity. Spatially, high-risk zones (>200 mg/L) emerge earlier under wetter conditions—under the baseline scenario (S0), such zones form by 2033 and exceed site boundaries by 2037. Plume expansion scales positively with extraction intensity, reaching its maximum advancement and coverage under the high-extraction scenario. These findings demonstrate dual drivers—precipitation accelerates contaminant accumulation through enhanced leaching, while groundwater extraction promotes plume expansion via heightened hydraulic gradients. This work elucidates coupled climate–human activity impacts on landfill contamination mechanisms, proposing a transferable numerical modeling framework that provides a quantitative scientific basis for post-closure supervision, risk assessment, and regional groundwater protection strategies, thereby aligning with China’s Standard for Pollution Control on the Landfill Site of Municipal Solid Waste and the Zero-Waste City initiative. Full article

A major factor in worldwide ecological harm is the large quantity of municipal solid waste generated because of rapid industrialization and population growth. Nowadays, there are numerous mechanical, biological, and thermal waste treatment processes that can reduce the amount of landfilled waste. A variety of analytical tests are conducted to evaluate the potential risks that landfills pose to human health and the environment. Among these, laboratory leaching tests are commonly employed to assess the release of specific waste constituents that may become hazardous to the environment. Municipal solid waste (MSW) management poses significant environmental risks due to leachate contamination in bioreactor landfills, where acidic conditions (pH ≈ 5) can mobilize heavy metals. This study evaluates the reliability of leaching tests for biodried reject MSW from CWMC Marišćina, Croatia, by comparing standard EN 12457-1 and EN 12457-2 methods (L/S = 2 and 10 L/kg) with simulations of aerobic degradation using acetic acid (10 g/L) to maintain pH = 5 over 9 days. Waste composition analysis revealed plastics (35%), paper/cardboard (25%), metals (15%), and glass (10%) as dominant fractions. Although the majority of parameters determined through standard leaching tests remain below the maximum permissible limits for non-hazardous waste, simulations under acidic conditions demonstrated substantial increases in eluate concentrations between days 6 and 9: Hg (+1500%), As (+1322%), Pb (+1330%), Ni (+786%), and Cd (+267%), with TDS rising 33%. These results highlight the underestimation of risks by conventional tests, emphasizing the need for pH-dependent methods to predict in situ leachate behavior in MBO-treated waste and support improved EU landfill regulations for enhanced environmental protection. Full article

Background: Municipal solid waste management is a relevant component of climate and air quality policy, yet published life cycle assessments report inconsistent conclusions on whether sanitary landfilling, waste-to-energy incineration, composting, or anaerobic digestion yields the lowest greenhouse gas and co-pollutant impacts because results depend strongly on methodological choices and local context. Objective: To synthesize and critically evaluate how key life cycle assessment assumptions and boundary decisions influence reported emissions across major waste management pathways, with primary emphasis on the United States and selected comparison to European Union policy frameworks. Methods: Peer-reviewed life cycle assessment studies and supporting technical and regulatory sources were reviewed and compared, focusing on functional unit definition, system boundaries, time horizon, energy substitution and crediting methods, and treatment of methane, nitrous oxide, and air pollutant controls; drivers of variability were identified through structured cross study comparison and sensitivity-focused interpretation. Results: Reported pathway rankings vary primarily with landfill gas collection and utilization assumptions, the carbon intensity of displaced electricity or heat for waste-to-energy systems, and the representation of biological process emissions across active and curing stages; harmonized comparisons reduce variability but do not yield a single consistently superior pathway across all plausible settings. Conclusions: Comparative conclusions are context-dependent and policy-relevant interpretation requires transparent reporting and sensitivity analysis for capturing efficiency, substitution factors, and biological emission controls, along with clear alignment between modeled scenarios and real-world operating conditions. Full article

The juice industry generates substantial quantities of solid waste and wastewater. Consequently, efforts have focused on their treatment and valorization to obtain high-value-added products. Traditionally, these wastes are managed through landfill disposal and treatment in municipal wastewater facilities, respectively. In the present work, two alternative scenarios for the valorization of orange juice waste were developed and assessed in comparison to the conventional approach by performing a Life Cycle Assessment (LCA). Scenario 1 involved hydro-distillation of solid waste for essential oil recovery, followed by anaerobic digestion for biogas and fertilizer production, with wastewater treated via membrane filtration and chlorination. In Scenario 2, solvent-free microwave extraction (SFME) was employed for essential oil recovery, followed by anaerobic digestion. Wastewater was treated in a membrane bioreactor followed by ultraviolet treatment. According to the results, Scenario 1 achieved a 36% reduction in greenhouse gas emissions due to the beneficial effects of biogas and fertilizer production, despite its high energy demands. Scenario 2 exhibited the best environmental performance due to lower energy demands and higher extraction efficiency compared to Scenario 1, with reductions of 46% in greenhouse gas emissions and 48% in resource depletion. Overall, the findings highlight the potential of integrating innovative, energy-efficient technologies for the sustainable valorization of juice industry waste, offering measurable environmental advantages for industrial-scale implementation. Full article

The study evaluates the long-term environmental performance of natural filtration dams for leachate treatment at a municipal solid waste landfill. Field measurements of a system operating for 24 years, equipped with natural clay-loam filtration barriers, provide empirical validation for assessing the effectiveness and durability of natural material-based treatment approaches. Hydrogeological studies, including well drilling, water sampling, and comprehensive chemical analysis, demonstrate that the cascade filtration system achieves pollutant removal efficiencies of 80–95% for major contaminants. Physical property measurements reveal progressive density reduction from 1005 to 994 kg/m³ and viscosity decreases from 1.048 to 1.011 cSt across the treatment system. Numerical simulations demonstrate that contaminant transport under actual site conditions remains diffusion-dominated over multi-decadal timescales, with aquifer concentrations remaining below 1% of source values after 50 years. Parametric studies reveal that density-driven convective fingering develops only at source concentrations exceeding 100 g/L. The findings validate the long-term viability of natural geological barriers combined with cascade filtration systems for cost-effective leachate treatment, demonstrating that preliminary treatment through natural filtration effectively suppresses gravitational instabilities and protects underlying aquifers. Full article

Solid waste management remains a critical challenge in rapidly urbanizing regions of the Global South, where limited infrastructure and informal disposal practices compromise environmental and public health. This study addresses the issue of illegal waste dumping in Dakar, Senegal, by integrating remote sensing, geographic information systems, and citizen science into a multi-criteria framework to identify areas most susceptible to dumping. Using Landsat 8 and Sentinel-2 imagery, indicators such as land surface temperature, vegetation, soil, and water indices were combined with demographic and infrastructural data. A citizen survey involving local university students provided social perception scores and criterion weights through the Analytic Hierarchy Process. The resulting susceptibility maps revealed that high and very high dumping probabilities are concentrated around the Mbeubeuss landfill and densely populated areas of Keur Massar, while Malika showed lower susceptibility. Sensitivity analysis confirmed the model’s robustness but highlighted the influence of thermal and social perception variables. The results show that 28–35% of the study area falls under high or very high susceptibility, with hotspots concentrated near wetlands, informal settlements, and poorly serviced road networks. The weighted model demonstrates stronger spatial coherence compared to the unweighted version, offering improved interpretability for waste monitoring. These findings provide actionable insights for the Société Nationale de Gestion Intégrée des Déchets (SONAGED) and for municipal planners to prioritize interventions in high-susceptibility zones. Rather than being entirely novel, this study builds on existing remote sensing, geographic information systems and citizen science approaches by integrating them within a multi-criteria framework specifically adapted to a West African context. Full article

Landfill disposal continues to be the most economically viable municipal solid waste (MSW) management practice in many countries, including Mexico. Landfills are the third-largest source of methane emissions from human activity, a fact that has significant implications for the environment and human health. Due to the difficulty in experimentally quantifying methane emissions, mathematical models have been employed to predict gas emissions. In this work, three first-order decay models were implemented to estimate methane emissions in a landfill located in the metropolitan area of Oaxaca City, Mexico. Each model incorporated a Van’t Hoff–Arrhenius-type approach for calculating the reaction rate constant. Additionally, an uncertainty analysis of the models was presented, applying Monte Carlo simulations with triangular and log-normal distributions. The results show that the simple model exhibited the best predictive performance. For 2020, the simple model estimated 3,488,392.1 m³ of methane at a temperature of 46 °C, 3,509,625.1 m³ of methane at 47 °C, and 3,530,850.2 m³ of methane at 48 °C. The Monte Carlo simulation with a log-normal distribution exhibited more robust and natural process behavior. For the simple model, the mean was 3,486,946.03, the median was 3,487,154.73, and the standard deviation was 212,095.95. The LandGEM model exhibited more linear methane generation behavior, and the uncertainty analysis confirmed that this model had the lowest predictive capability of the three proposed models. Full article

This article investigates technological choices for Waste-to-Energy (WtE) implementations in Municipal Solid Waste (MSW) management. It identified challenges and opportunities, thereby transforming the perspective of MSW from waste into a valuable resource. The methodology included a systematic literature review, following PICO and PRISMA protocols. The analysis included 118 open-access review articles, published between 2018 and 2024, from Web of Science, Scopus, and ScienceDirect, concerning thermochemical, biochemical, and chemical technologies. Key challenges for new implementations include economic barriers, social issues, and regulatory shortcomings. Opportunities arise from education, supportive policies, and lessons learned from developed countries such as Germany and Japan. Limitations include the focus on specific databases and the potential oversight of data from other sources or unexamined data. Implications for future research should expand coverage as well as assess longer periods to enhance MSW valorization. Implications also include guidance for public managers and policymakers in formulating MSW management strategies, including policies, WtE technology selection, public education, and reducing misinformation to boost implementation and social acceptance of WtE initiatives. Effective WtE implementation improves public health and the environmental performance of regions by reducing landfills and generating economic and employment opportunities for vulnerable communities. The study’s originality lies in bridging a significant research gap on WtE implementation through a comprehensive examination of its challenges and opportunities. By integrating international experiences and lessons learned, it generates guidance for the sustainable development of MSW management systems. Full article

Despite widespread implementation, current waste management practices—such as landfilling and incineration—are associated with significant environmental drawbacks, including greenhouse gas emissions and resource loss. Consequently, the search for more sustainable and environmentally friendly waste valorization methods has highlighted oxidative liquefaction as a promising pathway. This study focused on two critical waste streams: personal protective equipment (PPE) and municipal solid waste (MSW). These categories were selected due to the significant increase in PPE waste generated during the recent pandemic, as well as the need to develop effective strategies to address potential future surges in such waste streams. Experiments were carried out at 200–300 °C, with waste-to-liquid ratios of 3–7% and oxidant concentrations of 30–60 wt.%. The aim was to demonstrate the potential of oxidative liquefaction as a thermochemical conversion route for resource recovery, enabling the breakdown of the organic matrix of PPE and MSW into valuable liquid products such as fine chemicals or a source of carbon in biotechnological processes. Chromatographic analyses, combined with chemometric methods, revealed how temperature, waste-to-liquid ratio, and oxidant concentration affected the yield and composition of oxygenated chemical compounds (OCCs). Using raw chromatographic data directly in optimization eliminated the need for manual gas chromatography (GC) signal processing and provided a faster approach to process evaluation. The results confirmed distinct differences in degradation behavior and OCC formation between PPE and MSW, with maximum yields of 183–212 gOCC/kg for PPE and 51–69 gOCC/kg for MSW. These findings highlight the strong influence of physicochemical waste properties on degradation and product composition. Overall, oxidative liquefaction shows significant potential as a waste-to-value strategy, supporting renewable fuels, chemical precursors, and circular economy development within the framework of biomass, biofuels, and waste valorization. Full article

Municipal solid waste (MSW) management in Brazil faces significant challenges related to waste segregation, collection efficiency, and environmentally adequate disposal. This study quantifies the carbon emissions associated with organic solid waste management, from 2022 to 2034, in the city of João Pessoa (Northeast Brazil). To this end, the Life Cycle Assessment methodology is applied to two scenarios: Scenario 1 (where all organic fraction is landfilled) and Scenario 2 (progressive implementation of composting for the domestic organic waste, starting in 2023, with increases each year until reaching 50% in 2034, and the remainder being landfilled). The latter is proposed based on the targets established in the Municipal Solid Waste Plan of João Pessoa. Projection for MSW considered a per capita rate of 0.86 kg/inhab.day, combined with a population growth rate of 1.92%/year. The results indicate that Scenario 1 emits 825 Mt CO₂-eq while Scenario 2 emits 704 Mt CO₂-eq for the study period (a reduction of 15%). A sensitivity analysis examined the effects of increasing transport distance (25–45 km) and the organic fraction of MSW (35–45%) on GHG emissions. Although total emissions rose under both conditions, the comparative environmental advantage of composting over landfilling remained stable. These results confirm the robustness of the analysis and reinforce composting as a low-carbon, effective strategy for managing urban waste. Full article

According to the EU Directive 2018/851 on waste, by 2035 the amount of municipal waste sent to landfills should be reduced to 10% of the total amount of household waste, and the level of reuse and recycling of municipal waste should be increased to 65% [...] Full article

The massive production of municipal solid waste presents a significant global challenge for sustainable urban development and maintaining citizens’ quality of life, requiring effective management and disposal strategies. Waste-to-energy incineration technology has become increasingly important as a solution that simultaneously addresses the growing volumes of municipal solid waste and rising energy needs worldwide. This comprehensive review examines the research findings on the effectiveness of incineration as a waste-to-energy conversion method. The primary goal was to conduct a thorough systematic review assessing WtE incineration effectiveness across several key areas: energy recovery efficiency, waste volume reduction capabilities, environmental impact, and economic feasibility. A comprehensive literature search was conducted across ScienceDirect and additional pertinent databases, utilizing appropriate search terms in accordance with the PRISMA framework. A total of 431 studies were systematically identified, published between 2015 and 2025, and only 25 relevant studies were included in this review. Researchers collected data focusing on energy recovery percentages, volume reduction rates, emission reductions, and economic performance metrics. The findings revealed that every study included in the analysis showed positive results for WtE incineration across various performance measures. This research discovered the feasibility of generating electrical power from garbage through WtE incineration processes. The projected energy yields, ranging from gigawatt-hours to kilowatt-hours, were quantified for several nations, including Mexico (11,681.64 GWh), Cambodia (1625.81 GWh), Bangladesh (187.04 GWh), South Africa (6944 GWh), Iran (17,678 GWh), Nigeria (10,000 GWh), Indonesia (2487 MWh), Algeria (11.6 MWh), China (2316.52 MWh), Iraq (203.917 MWh), Uganda (774 kWh), and Pakistan (675 kWh). Energy recovery efficiency demonstrated a wide range from 30% to 92.75%, with waste volume reduction consistently reaching 90–95% levels, significantly prolonging landfill operational lifespans. From an environmental perspective, technology achieved greenhouse gas emission reductions ranging from 30% to 87%. This dual-purpose approach makes it an attractive, sustainable solution for both waste management and renewable energy production. By adopting this approach, cities can address waste and energy issues while boosting economic growth and job creation. However, it also involves substantial costs, technical difficulties, and environmental hazards that necessitate meticulous oversight. Full article

Over 292 million tons of municipal solid waste (MSW) are generated annually in the United States, with more than half disposed of in landfills. Municipal solid waste landfills (MSWLFs) are stationary sources of air pollution and potential health risks for nearby communities. The Agency for Toxic Substances and Disease Registry (ATSDR) has completed over 300 public health assessments (PHAs) and related investigations at MSWLFs and open dumps since the 1980s. This paper reviews the ATSDR’s evaluations of air pathway concerns at 125 MSWLF sites assessed between 1988 and early 2025, with many being evaluated during the 1990s. Most sites were located in the Midwest and Northeast, and only 25% remained active. The ATSDR found no air-related public health hazard at 86% of sites. At sites where hazards were identified, common issues included elevated outdoor or indoor toxicants (e.g., hydrogen sulfide, benzene, trichloroethylene, and mercury) and unsafe methane accumulations. Contributing factors included older site designs, inadequate gas-collection, subsurface fires, and distance from nearby residences. Corrective actions effectively reduced exposures at the affected sites. Results suggest that well-located and maintained landfills minimize public health hazards, while aging or poorly managed sites pose risks. Continued monitoring and research are warranted as waste management shifts toward reducing, reusing, recycling, composting, and energy-recovery technologies to improve efficiency, advance technologies, and address systemic public health challenges. Full article