Search Results (2,662)

Waste-to-hydrogen (W2H) technology is gaining recognition as a viable pathway for simultaneous waste valorisation and clean energy production in the Gulf Cooperation Council (GCC). However, the water resource implications of hydrogen production pathways in this acutely water-scarce region have received insufficient analytical attention. This paper presents the first systematic comparative analysis of water consumption across grey, blue, green, and waste-to-hydrogen production pathways calibrated to the GCC context, using the ISO 14046 water footprint framework and accounting for the desalination penalty that arises when hydrogen facilities draw on energy-intensive desalinated water. The analysis shows that green hydrogen, widely promoted in GCC national hydrogen strategies, incurs a compound water–energy burden substantially greater than global benchmark figures suggest, with electrolysis requiring 9 to 18 litres of water per kilogram of hydrogen and desalination accounting for 4 to 20 per cent of GCC electricity consumption. In contrast, W2H gasification exhibits considerably more modest water demands at 10 litres per kilogram of hydrogen, with high potential for treated wastewater substitution and co-location with municipal waste infrastructure, positioning it as the most water-compatible near-term hydrogen production pathway for arid GCC economies. Drawing on the water–energy nexus and water governance literature, the paper proposes a Water–Hydrogen Governance Framework comprising four policy pillars: water efficiency standards for hydrogen production facilities, water allocation policy for industrial hydrogen projects, integrated water–energy planning at the national level, and regional GCC coordination on water–hydrogen governance. The framework is aligned with SDGs 6, 7, 13, and 17 and provides a structured and practical tool for GCC governments and development institutions seeking to integrate water security into hydrogen strategy. The findings contribute to the emerging literature on resource-constrained hydrogen deployment and offer a replicable governance model for other arid economies pursuing clean hydrogen transitions. Full article

This review evaluates pretreatment strategies for blending the organic fraction of municipal solid waste (OFMSW) with agricultural residues to recover fermentable sugars. Three mechanistic benefits have been hypothesized for such blends: ash-mineral pH buffering, endogenous protein reduction of non-productive cellulase–lignin binding, and inhibitor dilution. These mechanisms are inferred from analogous lignocellulosic systems rather than measured directly in OFMSW–agricultural residue combinations, and their translation into saccharification gains remains substrate- and pretreatment-specific. A synergy index framework with a four-tier classification (true synergy, additive, substitution, and process complementarity) is applied to reclassify the available evidence, alongside an assessment of pretreatment chemistry, enzymatic hydrolysis outcomes, and techno-economic feasibility. Integrated sequential pretreatment, particularly acid-catalyzed steam explosion and deacetylation with mechanical refining, proved most robust for heterogeneous feeds. The strongest Tier I synergy is found for SO₂-catalyzed steam explosion of hybrid poplar–wheat straw (SI 1.29–1.33; 22% monomeric sugar gain). OFMSW combined with organosolv beechwood cellulose at 35–45% OFMSW reached 58–68% saccharification (44–46 g sugar L⁻¹), a Tier III–IV outcome. Matched-control saccharification data for OFMSW–agricultural residue blends specifically have not been reported. Co-processing corn stover with wet organic waste reduced CO₂ mitigation cost from $236 to $67 per ton CO₂-eq under bio-CNG upgrading. Formal synergy quantification, blend-specific inhibitor profiling, and high-solids process intensification are the central prerequisites for commercial translation. Full article

The transition toward renewable energy sources has become a critical global objective. For developing nations facing the dual challenges of inefficient waste management and limited energy access, waste-to-energy (WTE) technologies offer a transformative solution to mitigate environmental concerns while enhancing power grid stability. This paper presents a detailed performance analysis of a proposed WTE thermal power plant for Dire Dawa City, Ethiopia, utilizing municipal solid waste (MSW) as a sustainable feedstock. The primary objective of this study is to estimate the power generation potential of the city’s MSW through thermal incineration integrated with a Rankine Vapor Cycle. Field data collection reveals that Dire Dawa City produces an average of 237.2 tons of waste daily, with a per capita generation rate of 0.49 kg. Laboratory characterization indicates that the waste possesses high energy potential, featuring an average calorific value of 18.20 MJ/kg (18.20 × 10³ kJ/kg), a volatile matter content of 73.50%, and fixed carbon at 19.18%. Thermodynamic modeling and energy-flow simulations demonstrate that the facility can achieve a power output ranging from 7.64 MW to 22.80 MW, providing a nearly constant total energy yield of approximately 183,360 kWh per day. These results confirm that Dire Dawa City’s waste stream is a potent strategic resource for renewable energy. Ultimately, this research provides a technical roadmap for stakeholders, facilitating informed investment decisions and resource planning to ensure the successful implementation of sustainable thermal energy infrastructure in the region. Full article

A quaternary solid-waste-based binder was prepared from low-titanium slag, municipal solid waste incineration (MSWI) fly ash, steel slag, and flue-gas desulfurization gypsum (FGDG) to clarify the activating effect of MSWI fly ash on low-titanium slag and its influence on hydrate evolution. Unlike conventional solid-waste-based binders in which MSWI fly ash is mainly regarded as a hazardous residue requiring stabilization, this study demonstrates its specific role as a Ca-rich alkaline activator for promoting low-titanium slag depolymerization and coordinated hydrate formation. The results showed that the compressive strength first increased and then decreased with increasing MSWI fly ash content. Considering both strength development and MSWI fly ash utilization, the optimum mixture was identified as low-titanium slag:MSWI fly ash:steel slag:FGDG = 43.0:17.2:25.8:14.0, with compressive strengths of 9.51 and 46.32 MPa at 3 and 90 d, respectively. These values corresponded to 5.66 and 1.04 times those of the reference mixture without MSWI fly ash, respectively. Ettringite and C-(A)-S-H gel were the main strength-contributing hydration products, while Friedel’s salt was identified as a chloride-bearing AFm phase. Moderate MSWI fly ash addition promoted alkaline activation and low-titanium slag depolymerization, leading to increased formation of ettringite, C-(A)-S-H gel, and Friedel’s salt, which contributed to improved compressive strength. In contrast, excessive MSWI fly ash disturbed the Ca-Si-Al balance and inhibited effective hydrate formation. These results demonstrate that MSWI fly ash can serve as an effective Ca-rich activator for low-titanium-slag-based low-carbon cementitious materials and provide a feasible route for the synergistic utilization of multiple solid wastes. Full article

Sustainable phosphorus (P) management in agriculture requires a circular economy approach through the use of so-called bio-based fertilizers (BBFs). The properties of BBFs vary widely depending on raw materials and production processes. However, it is still unknown how these properties, and particularly the dominant P compounds determine not only the efficiency of BBFs in supplying P to crops, but also their effects on soil functioning and crop quality. This study aimed to evaluate the efficiency of a representative set of BBFs, and relate this efficiency to their composition and dominant P compounds. To this end, 14 BBFs were studied: four from water purification (struvite, vivianite, and sewage sludge with and without composting), four composts (municipal solid waste (MSW), vineyard residues, and two using olive husks), three vermicomposts (two homemade and one commercial), fish meal, digestate, and a commercial organic fertilizer. Phosphorus forms in BBFs were determined using ³¹P nuclear magnetic resonance spectroscopy (P-NMR). The BBFs were compared to a single superphosphate (SSP) in a pot experiment growing wheat in two different alkaline soils, one rich in iron (Fe) oxides and one rich in carbonates. The effects on critical elements in grain [magnesium, Fe, zinc (Zn), manganese, and copper] and enzyme activities related to soil functioning and P cycling were also assessed. The dominant P compound in the BBFs was orthophosphate (73.8–89.5% of the total P in the NaOH–EDTA extracts). The MSW had the highest polyphosphate content (4.1%), a complex inorganic P compound. The organic P content ranged from 9.2% (fish meal) to 25.5% (Moge). Sewage sludge and composted sludge contributed high levels of phosphonates (4.1 and 5.6% of extracted P). The most abundant organic P compound class was inositol hexakisphosphates (IHPs), and myo-IHP (phytate) was the dominant IHP stereoisomer (1.2–6.4%) followed by D-chiro-IHP and scyllo-IHP. Plant dry matter and grain yield with most BBFs were not significantly different from that of SSP in both soils, likely due to the high concentrations of phosphate in relatively soluble forms in most of the BBFs. Vivianite and sewage sludge resulted in significantly higher grain yield than SSP (43% and 40%, respectively) in the carbonate-rich soil, likely due to progressive phosphate dissolution, which decreased the precipitation rate of insoluble calcium (Ca) phosphates. The highest P recoveries were obtained with horse manure vermicompost (65% and 15% higher than SSP in the Fe oxide-rich and in the carbonate-rich soil, respectively), partially attributed to the decreased precipitation rate of insoluble Ca phosphates with the added organic matter. Some BBFs increased micronutrient concentrations in grains and most decreased the P-to-Zn ratio relative to SSP. Overall, phosphatase and β-glucosidase activities increased with carbon-rich BBFs. Most of the studied BBFs could effectively replace fertilizers from non-renewable sources, in some cases with better crop P recoveries. Furthermore, some BBFs could provide additional benefits to grain quality, in terms of micronutrient supply for humans, and soil functioning. Full article

Municipal solid waste landfills may remain sources of environmental concern long after closure because heavy metals can persist in soils and affect ecosystem recovery. This study presents an integrated assessment of a closed municipal solid waste landfill in Kokshetau, Northern Kazakhstan, by combining field-based soil geochemical analysis with remote sensing monitoring of vegetation dynamics. A radial-gradient sampling design was used to characterize spatial patterns of contamination and to distinguish zones with different levels of anthropogenic impact. The results showed a clear concentration of heavy metals, particularly Zn and Pb, in the central part of the landfill, where integrated pollution and ecological risk indices indicated the highest levels of technogenic pressure. Time-series analysis of Landsat-derived vegetation indices for 2017–2025 revealed poorer vegetation condition in the most contaminated areas, with NDVI and EVI values increasing toward the landfill periphery. The observed negative association between vegetation indices and ecological risk suggests that remote sensing indicators can provide useful information on the ecological condition of closed landfill sites, although they should be interpreted together with field measurements. The novelty of this study lies in the combined use of geochemical contamination indices and long-term vegetation-index monitoring to assess post-closure landfill conditions in an arid continental region of Central Asia, where such integrated studies remain limited. The findings highlight the persistence of environmental risks after landfill closure and support the use of vegetation indices as non-invasive tools for monitoring rehabilitation and prioritizing further field investigations. Full article

Achieving a circular and climate-neutral bioeconomy by 2050 requires not only high-quality recycling but also the large-scale integration of renewable carbon from biomass and atmospheric CO₂ into material systems. Plastics represent the world’s largest and most rapidly growing carbon sink, positioning them as a critical intervention point for replacing fossil-based feedstocks with renewable alternatives. Because plastic packaging is one of the most visible material streams encountered by consumers in daily life, a transition toward sustainable, recyclable bioplastics has the potential to deliver both meaningful environmental benefits and strong societal impact, accelerating public awareness and acceptance of renewable carbon solutions. Poly(ethylene furanoate) (PEF)—a fully bio-based polyester synthesized from plant-derived 2,5-furandicarboxylic acid (FDCA) and monoethylene glycol (MEG)—offers a promising pathway toward more sustainable packaging due to its superior mechanical strength and gas-barrier performance relative to polyethylene terephthalate (PET). This study presents a cradle to grave life cycle assessment (LCA) of PEF resin production and PEF bottle applications, using industrially relevant, at-scale process data covering biomass feedstock conversion, polymer synthesis, packaging manufacture, use phase, and end of life. Bottle applications were selected as a focal point due to their technical maturity, commercial relevance, and suitability for direct comparison with incumbent PET systems. The results indicate that PEF can reduce greenhouse gas emissions by up to 71% and fossil resource depletion by 26% compared to PET at the resin level when biogenic carbon uptake is included. Moreover, the material’s enhanced functional properties enable lightweight, recyclable bottle designs with carbon footprint reductions of up to 88% for 500 mL formats under a baseline recycling rate scenario of 72%, with the remaining share directed to municipal solid-waste incineration with energy recovery. Sensitivity analyses reveal that virgin PEF maintains environmental advantages over PET even when PET incorporates high levels of recycled content, highlighting the complementary roles of renewable carbon and circular material strategies. Prospective scenario modeling underscores the importance of sustainable feedstock selection and process electrification, with sucrose-based routes offering the largest potential for further decarbonization. Overall, the findings demonstrate that PEF is a scalable biopolymer capable of delivering substantial climate benefits while supporting circularity objectives. By targeting a highly visible consumer application—plastic packaging—this transition amplifies the societal impact of adopting renewable carbon materials. The study provides actionable insights for policymakers, industry stakeholders, and sustainability practitioners working to advance a more resilient, renewable, and consumer-recognizable plastics economy. Full article

Sustainable municipal solid waste (MSW) treatment in rapidly urbanizing secondary cities requires evidence-based, district-level prioritization of technologies. We integrate GIS hotspot mapping, Random Forest, and AnyLogic System Dynamics into a decision-support framework and apply it to Shymkent, Kazakhstan (population 1.19 million; ≈301,400 tonnes of MSW in 2025). This is the first application of such a framework to MSW management in a Kazakhstani secondary city and, to our knowledge, the first regional application across Central Asia; the integration concept has prior precedents in Latin American, South Asian, and East Asian metropolitan studies, and the present contribution lies in empirical calibration to a Central Asian upper-middle-income context using 2015–2025 morphological audits, air-quality and soil monitoring, and Sentinel-2 NDVI. Random Forest (n = 80, 9 predictors) achieved R² = 0.976 ± 0.011 under 5-fold cross-validation; a complementary GroupKFold protocol confirms the model is Shymkent-calibrated while the methodology remains transferable. AnyLogic simulation shows an Infrastructure/Waste-to-Energy pathway reduces the 2030 annual landfilled volume to ≈201 kt, environmental risk by 70%, and methane emissions by 86% (≈270 kt CO₂-eq/year) relative to the Inertial baseline. The principal deliverable is a District × Technology × Phase prioritization matrix for sequencing sustainable investment under realistic budget constraints. Full article

In this study, phenol adsorption from aqueous solutions was investigated using a carbonized adsorbent derived from a 1:1:1 mixture of banana, carrot, and potato peels, representing a major fraction of municipal bio-waste in Serbia. The material (CARB_BCP) was characterized by pH_pzc, SEM, FTIR, and BET analyses. The results indicated a highly porous structure with developed micro- and mesoporosity and a high specific surface area (S_BET = 483 m²/g). FTIR confirmed the formation of a stable aromatic carbon structure, while the high pH_pzc value (10.55) suggested a limited role of electrostatic interactions. Adsorption experiments performed at an initial phenol concentration of 1858 mg/L, room temperature, and an adsorbent dose of 0.1 g achieved a removal efficiency of 20.5%. The Langmuir model provided the best fit, indicating monolayer adsorption, with good agreement between theoretical (≈187 mg/g) and experimental (≈190 mg/g) capacities. Kinetic analysis followed the pseudo-second-order model, suggesting chemisorption as the rate-controlling step. The adsorption mechanism was mainly governed by π–π interactions, hydrophobic effects, and hydrogen bonding. These results demonstrate that CARB_BCP, derived from biodegradable waste, is a promising low-cost adsorbent for wastewater treatment. Full article

The geographic and economic contexts play a major role in decision-making when it comes to municipal solid waste management. In the present study, simulations are carried out using the Waste and Resource Assessment Tool for the Environment (WRATE) software academic version 3.0.1, based on the Ecoinvent database (version 2) to assess the greenhouse gas emissions released by 1 ton of municipal solid waste with a typical composition characterizing upper middle-income countries, with an organic fraction of approximately 50% by weight. The variation over time (2000 to 2022) with no intended transformation in the management strategy is first analyzed, then several transformations are applied by varying the waste management routes (open dumping, landfilling, recycling and composting) as well as the energy recovery integration. The results are then discussed based on the waste categories and the performed operations (landfilling, recycling, transportation, treatment and recovery). The results revealed that the most promising scenario includes limited open dumping that does not exceed 10%, landfilling with at least 20% energy recovery, and major fractions addressed to composting and recycling. Overall, this scenario returns a negative carbon footprint with a value of approximately−0.35 tons of CO₂-Eq/ton of MSW. Results are mostly applicable to countries with similar waste composition and infrastructure levels; preconditions include source segregation, compost markets, and landfill gas infrastructure. Full article

Environmental health services play a critical role in communicable disease outbreaks by addressing environmental determinants of disease transmission. However, the scope, impact, and challenges of Environmental Health Practitioner (EHP)-led interventions remain insufficiently documented. Aim and objectives: This systematic review objectively assessed the role, impacts, and challenges of municipal environmental health services in outbreak response, with a focus on South Africa, to inform the standardisation and strengthening of disease surveillance and prevention. Methods: The PICO framework guided the development of search terms and research questions. PubMed, Scopus, Google Scholar, and Web of Science were searched for English-language, full-text studies published between 2010 and 2024. Studies not meeting these inclusion criteria were excluded. Screening and reporting followed PRISMA guidelines, and data were synthesised using a standardised extraction tool. Results: A total of 58 studies were included. The key EHP functions identified were water quality monitoring, vector control, food safety, waste management, and outbreak response. While South Africa demonstrated comparatively advanced systems, persistent implementation challenges remain, including the integration of environmental monitoring with disease surveillance. The findings emphasised the need for integrating environmental monitoring with disease surveillance systems and integrating WASH and climate-responsive strategies. Conclusions and recommendation: The review recommends strengthening guidelines and advancing evidence-based practice. Enhancing EHP roles within surveillance frameworks is essential for improving outbreak preparedness and public health resilience. Full article

The composition and type of polymers used as feedstocks in the pyrolysis of plastic waste determine the decomposition process and the proportions of the final products. This paper examines the effect of feedstock heterogeneity on pyrolysis efficiency and pyrolysis gas composition. Four types of plastic waste were considered: real polyolefin waste of municipal origin, LDPE, Alu-PEX laminates, and an alternative refuse-derived fuel (RDF). Low-temperature pyrolysis (450 °C) was conducted in a laboratory reactor, and the gas composition was analyzed using GC-TCD/FID gas chromatography, which allowed for the determination of light hydrocarbons, oxygenates, and sulfur content. Compared to RDF, both municipal and LDPE polyolefin wastes produced gas with a higher calorific value and a predominance of light C₁–C₄ hydrocarbons, while Alu-PEX laminates produced gas rich in C₁–C₂ and low in sulfur, suitable for direct use. RDF was characterized by increased CO₂ and non-flammable gas production and significantly higher sulfur content, requiring advanced purification. The results emphasize the importance of feedstock segregation and standardization and demonstrate that pyrolysis of polyolefins and Alu-PEX laminates can provide higher-quality energy gas than RDF, supporting the circular economy and energy self-sufficiency of industrial installations. Full article

This study presents a comprehensive assessment of high-temperature performance, economic viability, and environmental sustainability of alkali-activated slag paste (AASB) incorporating municipal solid waste incineration bottom ash (MSWI-BA). The research systematically evaluates the effects of MSWI-BA content (0–12%), alkali content (2–6% Na₂O equivalent), water glass modulus (Ms = 0.75–1.75), and activator type on key performance metrics, both resource recovery and carbon reduction goals. Results show that the optimized formulation (6% MSWI-BA, 4% Na₂O, Ms = 1.5) achieves superior high-temperature resilience, retaining 76% of its initial compressive strength after 800 °C exposure—a stark contrast to OPC, which undergoes near-complete strength loss. Economic analysis reveals that while MSWI-BA offers an 88% reduction in raw precursor cost, the optimized AASB incurs a modest 3.7% total material cost premium over OPC, which is offset by its long-term sustainability benefits. Furthermore, a life-cycle assessment demonstrates that AASB has a 66.95% lower carbon footprint than OPC. Full article

This study proposes and tests an analytical framework for interpreting digitally monitored municipal biowaste collection services through comparable diagnostics of operational performance, additional effort, and emissions intensity. The framework was applied to 572 collection services recorded between July and December 2025 in the Municipality of Barreiro, Portugal, covering seven circuits operating under different urban morphologies and collection configurations. Service-level operational records were transformed into physically interpretable performance indicators and an additional operational effort index was derived from robust normalization of serviced container density and service time per kilometer. The results showed marked heterogeneity across service regimes, with the highest effort observed in residential circuits characterized by greater spatial and temporal demand, while the non-domestic and communal circuits remained at or below municipal reference conditions. At the municipal scale, operational effort was moderately associated with mass collected per kilometer (ρ = 0.490, n = 572), weakly and non-significantly associated with mass per hour (ρ = 0.075, p = 0.074), and negatively associated with mass per container (ρ = −0.325). For services operating above municipal reference conditions (Eesf > 0, n = 286), emissions intensity was negatively associated with both effort components and with the aggregate effort index, with the strongest association observed for Eesf (ρ = −0.554). The results indicate that higher operational effort tends to coincide with greater spatial mass recovery, but not with higher container-level yield or proportionate improvements in emissions performance. More broadly, the study shows that the analytical value of digital monitoring depends not only on data availability, but also on the ability to convert routine service records into interpretable diagnostics for municipal decision-making. Full article