Search Results (6,855)

In developing countries, final disposal sites exhibit different levels of operational control, which influence their environmental performance. This study evaluated the environmental performance of four types of final disposal sites in Mexico: sanitary landfill with energy recovery (SLF+ER) and sanitary landfill with gas flaring (SLFGF), controlled site (CS), and open dump (OD), using life cycle assessment for 1 t of municipal solid waste. Biogas generation was estimated using the Mexican Biogas Model 2.0, and Ecoinvent processes were adapted to local conditions; six impact categories were assessed, and a sensitivity analysis was conducted. The SLF+ER scenario showed the lowest impact in global warming, followed by SLFGF and CS, while OD recorded the highest impact, mainly associated with biogas management. In contrast, scenarios with gas capture and treatment showed higher contributions in categories related to combustion processes. Normalized results indicated that freshwater eutrophication and human carcinogenic toxicity are the dominant impact categories. The sensitivity analysis confirmed the influence of the organic fraction on CH₄ generation without altering the relative ranking among scenarios. Overall, increasing the level of environmental control reduces impacts from fugitive emissions but introduces trade-offs across other impact categories, highlighting the need for comprehensive assessments to support decision-making. Full article

Coal gangue (CG) and iron tailings (ITs) are major industrial solid wastes, and their high-value reuse is crucial for sustainable construction materials. This study explores the feasibility of fabricating sintered porous bricks using CG and ITs as primary constituents, with shale as an auxiliary component. To evaluate durability in cold regions, laboratory freeze–thaw (F-T) cycling experiments were conducted. A degradation assessment framework based on the Wiener stochastic process was developed to predict frost-resistance service life by integrating experimental data with regional climatic conditions. Results show that the fabricated bricks exhibit satisfactory initial properties, with a compressive strength of 10.6 MPa and water absorption of 13.3%. With increasing F-T cycles, compressive strength decreases significantly, accompanied by increased mass loss and water absorption. Stress–strain analysis reveals progressive stiffness reduction and a transition from brittle to ductile failure. Microstructural observations confirm degradation of the glassy phase, pore expansion, and enhanced interconnectivity. The Wiener process-based model effectively describes the stochastic accumulation of F-T damage. By establishing equivalence between laboratory and natural F-T cycles, the long-term service life of coal gangue–iron tailing sintered porous bricks (CG-IT SPBs) in cold regions is theoretically evaluated. This work provides an integrated understanding of F-T damage behavior and establishes a scientific foundation for durability-oriented design and application of such bricks in extremely cold environments. Full article

Coal gangue is one of the most abundant solid wastes generated during coal mining. The use of coal gangue for underground backfilling is widely recognized as an effective approach to reducing waste accumulation and promoting sustainable utilization. To further investigate the bearing and deformation behavior of underground gangue filling materials, combined with the underground occurrence conditions of crushed gangue in goaf, a self-designed loading apparatus for crushed gangue was employed to perform lateral compression experiments on crushed gangue. The compaction deformation, fractal dimension, and acoustic emission evolution characteristics of crushed gangue under the influence of lithology, water content state, particle size distribution, and axial pressure were analyzed. The results indicate that higher rock strength, lower moisture content, smaller particle size range, and lower axial pressure significantly enhance the bearing capacity and reduce axial strain. The fractal dimension increases with decreasing rock strength, increasing moisture content, and increasing axial pressure, reflecting intensified particle fragmentation. The acoustic emission response exhibits three different stages, corresponding to void compaction, void filling, and structural adjustment. Axial pressure has been identified as the main factor controlling acoustic emission energy release, while water content significantly suppresses acoustic emission energy and event frequency. The key roles of particle sliding, rotation, and torque-driven rearrangement in controlling overall deformation were elucidated. These findings provide theoretical support for the mechanical behavior of gangue filling in the goaf and the sustainable disposal and resource utilization of mining waste. Full article

Using solid waste as supplementary cementitious materials (SCMs) is an effective strategy for promoting low-carbon construction development. However, single or binary systems often exhibit mismatched reaction kinetics, thereby limiting their performance at high cement replacement rates. This study focuses on a novel low-carbon concrete designed based on reaction sequence coordination, containing recycled brick powder (RBP), ground granulated blast-furnace slag (GGBS), and self-combusting coal gangue (SCCG). The effects of RBP, GGBS, and SCCG on the hydration process and microstructure of the novel low-carbon concrete with different replacement levels have been studied by testing compressive strength, workability, and durability and observing microstructural changes. The results showed that an optimized ternary composition with an RBP:GGBS:SCCG ratio of 4:3:1 achieves a cement replacement level of 30% while exhibiting a 28-day compressive strength of 38.26 MPa, representing a 14.2% increase compared with plain cement mortar. Microstructural analyses indicate that this enhanced performance results from a time-dependent reaction sequence, in which GGBS contributes predominantly at early ages by supplying calcium, whereas RBP and SCCG mainly participate through delayed pozzolanic reactions and pore refinement at later ages. Consequently, the optimized ternary mortar exhibits a water absorption of 11.12% and a 27.2% reduction in electrical flux. This study aims to provide practical strategies for enhancing the performance of low-carbon cementitious materials through a reaction sequence coordination design approach, thereby improving the utilization efficiency of solid waste in the production of low-carbon building materials. Full article

This paper presents a systematic review of compression casting concrete (CCC) based on a comprehensive literature retrieval from the Web of Science, covering publications from 2020 to 2026. CCC applies pressure on fresh concrete to expel excess internal water and air, driving the cement paste to fully penetrate the aggregate pores, which can significantly optimize the micro- and macro-properties of concrete. With environmental friendliness and resource-saving merits, CCC has become a global research hotspot in the field of civil engineering and construction. Research contributions have been made by scholars from China, Australia, Pakistan, France, the UK, India, Italy and other regions. This paper systematically elaborates the basic principles and core advantages of the compression casting technology, focusing on the analysis of key research directions, including mechanical properties, ductility improvement, durability, solid waste resource utilization (waste rubber particles, recycled concrete aggregates), compression-casting-reinforced concrete members and special-purpose preparation equipment. It analyzes the advantages and disadvantages from both micro and macro perspectives and demonstrates the engineering application feasibility and development potential of this technology. It is concluded that the mechanical properties of CCC with compressive strength exceeding 60 MPa still require further in-depth investigation, compression casting technology improves the utilization efficiency of red mud, durability research on CCC remains insufficient, and specialized equipment for large-scale reinforced concrete CCC members needs further development. Full article

The chemical equilibria of metal ions between soil solution and solid phases govern the solubility of metals in soil. However, the identity of these controlling phases remains poorly understood in historically polluted environments. This study aimed to identify the dominant mineral phases regulating the activities of Zn²⁺, Cd²⁺, Pb²⁺, and Ni²⁺ in soils subjected to long-term contamination from sewage sludge, municipal solid waste, river water, and industrial effluents across India. The soil samples were collected from various locations historically polluted by sewage sludge, municipal solid waste, polluted river water and industrial effluents. The free ion activities of Zn²⁺ (pZn²⁺), Cd²⁺ (pCd²⁺), Pb²⁺ (pPb²⁺) and Ni²⁺ (pNi²⁺) in soil pore water were estimated using the geochemical speciation model WHAM-VII. The metal ion activities were higher in industrial effluents and solid waste-treated soils as compared to other contaminated soils. The solubility of Zn and Cd in soils contaminated with Zn-smelter effluents was controlled by franklinite (ZnFe₂O₄) in equilibrium with goethite (α-FeOOH) and otavite (CdCO₃), respectively. Identification of minerals further reveals that nickel ferrite (NiFe₂O₄) in equilibrium with lepidocrocite (γ-FeOOH) governs the activity of Ni²⁺ in cycle factory effluent-irrigated soils of Sonepat, Haryana. At the municipal solid waste-contaminated site, the Pb²⁺ activity was controlled by exchangeable Pb in soils, whereas Zn²⁺ activity was governed by willemite (Zn₂SiO₄) in equilibrium with quartz (SiO₂). These findings provide new insights into mineralogical controls on heavy metal solubility under diverse contamination scenarios. Formation of highly soluble minerals like otavite, willemite, and nickel ferrite suggested the potential ecological risk of Cd, Zn, and Ni, respectively, in polluted soils. Full article

Sustainable vegetable production requires strategies that optimize yield while conserving water and minimizing resource inputs. This study, conducted at the Horticulture Research Farm near Absaraka, ND, evaluated the performance of several paste-type tomato (Solanum lycopersicum) cultivars under different irrigation strategies in high-tunnel and open-field production systems to identify cultivar and irrigation combinations that support sustainable production. Across seasons and production environments, cultivar significantly influenced marketable yield, fruit number, fruit size, and the proportion of unmarketable fruit, whereas irrigation treatments had limited effects on total and marketable yield. High-yielding cultivars such as ‘Granadero’, ‘Pozzano’, ‘Cauralina’, and ‘Amish Paste’ consistently produced greater marketable yields in both production systems, although ‘Cauralina’ also exhibited higher levels of fruit cracking and unmarketable yield. In high-tunnel production, deficit irrigation strategies based on soil moisture thresholds (10% and 30% management allowable depletion) maintained yields comparable to time-based irrigation, suggesting that water-efficient irrigation scheduling can sustain productivity. In the open field, cultivar responses varied under different irrigation regimes, highlighting the importance of selecting cultivars adapted to water-limited conditions. Fruit quality attributes, including soluble solids content and titratable acidity, were primarily influenced by cultivar rather than irrigation. Overall, the findings demonstrate that cultivar selection combined with water-efficient irrigation management can maintain tomato productivity while reducing water use and production losses. These results support the development of more sustainable tomato production systems that enhance resource-use efficiency, reduce waste from unmarketable fruit, and maintain fruit quality across diverse production environments. Full article

In the Philippines’ agricultural setup, pre-harvest cacao (Theobroma cacao) fruits are wrapped with low-density polyethylene (LDPE) for moisture retention and damage protection. Responding to the growing concern for its waste volume and scarcity of treatment, this research explores the co-hydrothermal carbonization (co-HTC) of cacao shells (CS) and LDPE as a method to convert agricultural waste with plastic into hydrochar for potential energy applications. Thus, observations on the thermal, physicochemical, and morphological changes from feedstocks to hydrochar are carried out. Optimal conditions of 200 °C for 60 min resulted in hydrochar with 21.11 MJ/kg and appreciable thermal properties. SEM micrographs show that hydrochar had increased surface area, a good fuel characteristic, and surface flaking on oversized LDPE film, suggesting relative LDPE degradation. EDX analysis reveals C, K, Ca, and Zn metals that affect chemical pathways. FTIR analysis further supports chemical synergy by preservation of functional groups innate from both parent materials. Kinetic and thermal evolutions are also investigated to reveal the influence of pretreatment on the stability of cacao shell-dominated hydrochar and the effectivity of biomass integration to facilitate relatively easier cracking of LDPE. The findings support co-HTC as a viable technology to enhance the circular economy by valorizing LDPE and cacao shells while promoting energy recovery and solid fuel production. Full article

Solid-state fermentation (SSF) is a pivotal biotechnology in the circular economy, leveraging agri-food industrial waste and byproducts to produce high-value bioproducts while minimizing organic waste. By aligning with sustainability goals and zero-waste principles, SSF enables the production of enzymes, bioactive compounds, and secondary metabolites for food, agriculture, and biomedical applications. Recent advancements have optimized critical parameters, including substrate selection, culture conditions, and scalable bioreactor designs, enhancing process efficiency and reducing environmental impact. Despite progress, challenges persist in maximizing production yields and fostering industrial adoption. Addressing these hurdles, particularly through integrated environmental and techno-economic analyses, is essential to solidify SSF’s role as a sustainable and competitive bioprocessing method. This review analyzes the latest advances in SSF, including the valorization of food and agro-industrial wastes, innovative bioreactor designs, microbial engineering for more efficient strains, bioenergy production and its integration into biorefineries, and contributions to the circular bioeconomy. Thus, SSF emerges as a key technology in sustainable industrial biotechnology, offering eco-friendly alternatives and promoting a more efficient production model. Full article

The increasing popularity of fermented beverages, such as kombucha, has prompted the search of alternative ingredients with distinct functional and sensory properties. Orange (Citrus sinensis L. Osbeck) peel, an abundant by-product of the citrus industry, represents a valuable natural source of flavanones associated with multiple health benefits, offering a suitable substrate for fermentation. In this context, the present study proposes the valorisation of this by-product through the development of a new fermented beverage analogous to kombucha, rich in bioactive flavanones. During the fermentation process, variations were observed in physicochemical quality parameters (pH (4.86–2.91), titratable acidity (maximum 0.45% as acetic acid), and total soluble solids (TSS) (6.90–7.05 °Brix), as well as in the fermentation metabolites and substrates: sucrose (73.99–45.75 g/L), fructose (0.98–6.87 g/L), glucose (1.60–1.35 g/L), ethanol (0.06–0.24 g/L), and acetic acid (0.45–3.00 g/L). On the other hand, the initial total flavanone content (11.85 mg/100 mL), of which 70% corresponded to hesperidin, decreased during fermentation but then remained stable, reaching a final concentration of 5.72 mg/100 mL. Overall, these results highlight the potential of orange peel by-products for the development of innovative fermented beverages with a high content of bioactive flavanones, which are distinct from conventional tea-based kombucha. Moreover, this strategy represents a potential approach for this citrus waste valorisation, contributing to improved resource efficiency and supporting the transition towards a circular economy. Full article

The valorization of agricultural and food industry residues represents an important component of the circular bioeconomy, enabling the conversion of waste streams into value-added materials while mitigating environmental pollution. Spent coffee grounds (SCGs), a solid by-product generated during the extraction of coffee beans with hot water or steam, constitute an abundant lignocellulosic biomass residue. Due to their physicochemical properties, SCGs can be used as low-cost adsorbent materials for the treatment of metal-contaminated wastewater, offering a sustainable alternative to traditional synthetic resins. This review summarizes recent research on the application of SCGs for the removal of metal ions from aqueous systems. The adsorption performance of raw and modified SCGs, including materials obtained via carbonization and chemical functionalization, is comparatively evaluated. Furthermore, key operational parameters governing the adsorption process and the corresponding metal removal efficiencies are discussed. Full article

Accurate, high-resolution emission inventories are essential for air quality modeling and policy evaluation, yet national-scale inventories for Thailand remain limited in spatial and temporal detail. This study develops a comprehensive national emission inventory for Thailand in 2019 (EI–TH 2019), covering 12 major air pollutants and greenhouse gases across key sectors, including energy, transport, industry, agriculture, waste, and residential activities. The inventory is constructed using country-specific activity data from official statistics and sectoral surveys, combined with GAINS-consistent emission factors and control assumptions. Emissions are resolved at 1 × 1 km spatial resolution and monthly temporal resolution to capture Thailand-specific emission dynamics. The results show that emissions across major pollutants are dominated by a limited number of source groups, with biomass burning and residential solid-fuel use driving particulate matter, transport dominating NO_x and CO emissions, large-scale combustion and industry controlling SO₂ emissions, and agriculture contributing the majority of NH₃ emissions. Strong seasonal variability is observed in PM_2.5, CO, and NH₃, primarily driven by dry-season biomass burning, whereas NO_x and SO₂ exhibit relatively stable temporal patterns. The reliability of EI–TH 2019 is supported by a multi-dimensional evaluation framework. Temporal consistency is demonstrated through strong agreement between modeled PM_2.5 emissions and ground-based observations, as well as between NO_x emissions and satellite-derived TROPOMI NO₂ (r = 0.93; ρ = 0.96). Biomass burning timing is further validated using satellite fire activity (VIIRS), showing consistent seasonal patterns. Comparisons with global inventories (EDGAR v8.1, HTAP v3.2, and GFED5.1) reveal systematic differences in sectoral contributions, temporal profiles, and emission magnitudes, particularly for biomass burning, reflecting the importance of country-specific data and assumptions. Overall, EI–TH 2019 provides a robust, high-resolution, and policy-relevant emission dataset that improves the representation of emission processes in Thailand. The results highlight key priority sectors—biomass burning, transport, industry, and agriculture—for targeted emission-reduction strategies and support applications in chemical transport modeling, exposure assessment, and integrated air-quality and climate-policy analysis. Full article

Municipal solid waste (MSW) landfill site selection is a complex multi-criteria decision-making (MCDM) problem involving uncertainty and conflicting criteria. Although spherical fuzzy extensions of the Technique for Order Preference by Similarity to Ideal Solution (SF-TOPSIS) are widely used, existing studies rely on conventional distance measures that do not fully capture the geometric structure of spherical fuzzy sets. To address this limitation, this study proposes an enhanced SF-TOPSIS framework incorporating a novel spherical distance measure to improve consistency, discrimination capability, and structural compatibility. The framework integrates Spherical Fuzzy Weighted Arithmetic Mean (SWAM) and Spherical Fuzzy Weighted Geometric Mean (SWGM) operators and evaluates robustness using Spearman rank correlation. Additionally, a coefficient of variation (CV)-based analysis is conducted to examine the dispersion of closeness coefficients. The applicability of the approach is demonstrated through a landfill site selection case; however, the main contribution lies in a generalized distance-based formulation applicable to various MCDM problems. Results show that the proposed distance improves agreement between aggregation operators, increasing correlation values from 0.905 to 0.976, while producing a more stable distribution of closeness coefficients. Overall, the study advances spherical fuzzy MCDM by introducing a geometrically consistent distance formulation. Full article

Coal gasification slag (CGS) is rich in Si-Al-Ca components and thus has potential for ceramic utilization, but associated heavy metals may pose environmental risks. In this study, CGS from Yili (Xinjiang, China) was used as the major raw material (80 wt%), with clay and waste glass as additives, to prepare ceramsite by firing green pellets (8–12 mm) at 1000–1200 °C. The phase evolution, microstructure, and heavy-metal migration were characterized, and the leaching safety was evaluated. Increasing temperature leads to progressive quartz consumption, enrichment of feldspar-type crystalline phases, and liquid-phase sintering, which together enhance densification. The apparent density and single-particle compressive strength exhibit an “increase-then-decrease” trend with temperature and reach maxima at 1150 °C, where the compressive strength is 15.38 MPa. Heavy-metal behavior is element-specific: As and Zn show stronger volatilization, whereas Mn, Ba, Ni, and Cu are largely retained in the solid phase; Cr shows intermediate, temperature-dependent volatilization. After firing at ≥1150 °C, the leached concentrations of Cr, Mn, Ni, Cu, Zn, As, and Ba under the sulfuric acid–nitric acid test (HJ/T 299-2007) are below the Class III limits of the Chinese Groundwater Quality Standard (GB/T 14848-2017). Considering phase/structure evolution, mechanical performance, and short-term heavy-metal leaching, 1150 °C is identified as the preferred firing temperature in this work. Full article

To address ship-sourced water pollutant issues resulting from shipping industry growth and achieve precise supervision and effective management in coastal ports, this study develops a method for calculating and predicting the generation volume of oily sewage, domestic sewage and solid waste based on Automatic Identification System (AIS) data. First, a questionnaire survey (“Survey on Ship Water Pollutants”) is designed and implemented. Through analysis of questionnaire data, the ranges of values for the generation of oily sewage, domestic sewage, and solid waste from different ship types at China’s coastal ports are established. Additionally, onboard sampling is conducted to determine average emission factors for domestic sewage and oily sewage from typical ship types. Second, ship activities are derived from AIS data and combined with the established generation volume ranges for spatiotemporal calculation. Finally, a ConvLSTM (Convolutional Long Short-Term Memory) model is developed to predict the generation volume of water pollutant based on their spatiotemporal characteristics. Taking a major Chinese port area as a case study, the results indicate that pollutant generation volumes are significant in coastal port zones and main navigation channels, particularly between 15:00 and 16:00. chemical oxygen demand (COD), suspended solids (SS), and 5-day biochemical oxygen demand (BOD₅) levels in domestic sewage exceeded China’s national regulatory limits by 0.35 times, 2.88 times and 1.07 times, respectively, which can easily lead to a decrease in dissolved oxygen content in the water, affecting the respiration and survival of aquatic organisms. Petroleum content in oily sewage remained below the standard threshold. For pollutant generation volume prediction, the proposed ConvLSTM model achieved MAE and RMSE values of 0.0824 and 0.1433, respectively, outperforming other prediction models such as LSTM and CNN-LSTM. This research provides technical support for the prevention and control of water pollution from ships in coastal ports. The proposed AIS-driven framework and ConvLSTM prediction method are transferable and globally applicable, offering a reference for the environmental sustainability of port ecosystems, the global maritime pollution prevention, and the sustainable development of the shipping industry worldwide. Full article