Search Results (3,326)

Tri-reforming of methane (TRM) has emerged as a promising pathway for low-carbon syngas production by integrating steam reforming, dry reforming, and partial oxidation within a single process. This coupling enables simultaneous CH₄ utilization and CO₂ valorization while enabling internal heat generation and flexible adjustment of the H₂/CO ratio for downstream synthesis. However, TRM performance cannot be adequately evaluated using conversion or energy efficiency alone, because the process involves complex interactions among competing reaction pathways, transport phenomena, catalyst stability, and thermodynamic irreversibility. This review provides a multiscale critical assessment of TRM from both first-law energy and second-law exergy perspectives, linking reaction-network fundamentals to reactor-level behavior and system-level performance. The literature evidence shows that although high temperatures and near-autothermal operation can enhance CH₄ conversion and reduce external heat demand, these conditions may simultaneously intensify deep oxidation, hotspot formation, carbon-forming tendencies, and exergy destruction. While equilibrium analyses help define feasible operating windows, they are insufficient without kinetic modeling and reactor-scale studies that capture spatial non-uniformities and pathway competition. Across reported TRM systems, exergy destruction is consistently concentrated within the reformer, identifying the reacting core as the dominant thermodynamic bottleneck. Accordingly, the key challenge in TRM is not simply to maximize conversion but to preserve chemical work potential while maintaining syngas quality and operational stability. Viewed from this perspective, TRM is better understood as an irreversibility-aware multiscale design problem in which optimal performance depends on the integrated optimization of catalyst functionality, reactor architecture, heat management, and system-level operation. Full article

A pilot-scale moving-bed biofilm reactor (MBBR), operated under alternating intermittent aeration (IA) and non-aeration phases, was used for single-stage carbon (C) and nitrogen (N) removal from high-fluctuating municipal wastewater via simultaneous nitrification–denitrification. The reactor was operated under highly variable chemical oxygen demand to total nitrogen (COD/TN) ratios, low dissolved oxygen (DO) conditions, and progressively extended non-aerated periods to evaluate process robustness under real operational conditions. An active denitrifying biofilm developed on the carriers after 23 days of the anoxic start-up, as confirmed by batch activity tests. Under the most carbon-limited condition tested (COD/TN = 5.5), the application of 16 h·d⁻¹ of non-aerated phases at DO levels of 0–1.0 mg·L⁻¹ enabled simultaneous COD, N–NH₄⁺ and TN removal efficiencies of 70, 95 and 84%, respectively. These results confirm that transient IA is an effective strategy for simultaneous C and N removal at very low COD/TN ratios and real fluctuating influent concentrations. Energy assessment showed that extended non-aeration phases reduced blower energy demand by 67% and total plant energy consumption by 34%, improving the environmental sustainability of the single-stage process. The main novelty of this study lies in the pilot-scale validation of an IA-MBBR for SND using real municipal wastewater under naturally fluctuating C and N loadings, thereby bridging previous laboratory-scale evidence with realistic operating conditions. Full article

This study presents a gate-to-gate life cycle assessment (LCA) of an industrial sweet cherry sorting and packing facility in Greece, directly addressing environmental sustainability in agri-food supply chains through data-driven impact quantification and improvement pathways in post-harvest operations. The assessment focuses on a gate-to-gate system boundary encompassing all processes inside the cherry sorting and packing facility, while upstream cherry production and downstream waste management are modeled and reported separately to provide system-level context. Core-stage hotspots are then analyzed in detail in the Results section, highlighting the dominant role of electricity use compared with packaging materials. The functional unit is defined as 1 kg of packed, market-ready cherries at the factory gate. Primary data are obtained from high-resolution, batch-level measurements of mass flows, energy use, water consumption, packaging materials and waste streams over a full processing season, structured as virtual sensor outputs. These sensor-informed operational data are combined with secondary life cycle inventory information from established databases to quantify climate change impacts and identify environmental hotspots across materials, energy, water, and waste, thereby delivering a quantified picture of environmental performance in the post-harvest stage. The results show that corrugated cardboard and associated packaging components are among the main contributors within the facility-level, gate-to-gate system, while the Core stage accounts for 28.43% of total GWP100. Upstream cherry production dominates the overall Upstream–Core–Downstream climate footprint with 70.61% of total impacts. Moreover, practical mitigation scenarios are modeled, including packaging optimization, partial substitution of grid electricity with photovoltaic generation, and increased water recirculation. Ιn the combined mitigation scenario, where packaging optimization, low-carbon electricity and improved water management are implemented simultaneously, total GWP100 decreases from 114,207.32 to 92,500.27 kg CO₂-eq (−19.0%) relative to the baseline, providing actionable sustainability improvements for industry stakeholders and supporting Sustainable Development Goals (SDGs) related to climate action and resource efficiency. In addition, the proposed virtual sensor architecture and data workflow support continuous monitoring, eco-efficiency management and near-real-time LCA implementation in post-harvest agri-food systems, enabling operational sustainability. Full article

Cement clinker production is a thermal- and emissions-intensive process requiring high-temperature heat for drying, calcination, and sintering. This review provides a process-based assessment of refuse-derived fuel (RDF), solid recovered fuel (SRF), tire-derived fuel (TDF), and biomass as partial substitutes for coal and petcoke in modern dry-process cement kilns. The study synthesized the evidence from plant-scale trials, pilot and laboratory experiments, process modeling, computational fluid dynamics, emissions studies, life-cycle assessment (LCA), techno-economic analysis (TEA), and regional case studies to evaluate alternative fuels across fuel properties, kiln-zone suitability, process stability, clinker quality, emissions performance, and environmental outcomes. The review shows that stable co-processing generally requires fuels with net calorific values above 14 MJ kg⁻¹ and moisture contents below 15%, although TDF can provide 26–33 MJ kg⁻¹ and sustain high-energy kiln duty when sulfur, zinc, and steel residues are controlled. RDF, SRF, and biomass require pre-processing, homogenization, calibrated dosing, and continuous fuel-quality monitoring to limit incomplete burnout, deposit formation, volatile circulation, and clinker-quality variation. LCA studies show that 20% RDF thermal substitution can reduce global warming potential by about 3.3–4.2%, increasing to approximately 6.7% when avoided landfill methane credits are included. Modern abatement systems can maintain particulate matter at about 10–30 mg Nm⁻³ and PCDD/F below 0.1 ng TEQ Nm⁻³ under stable operation. The review concludes that alternative fuels are quality-dependent co-processing options whose mitigation role is complementary to clinker-factor reduction, energy-efficiency improvement, low-clinker binders, electrified heating, oxy-fuel calcination, and carbon capture. Full article

Islanded renewable microgrids must balance power internally, so day-ahead dispatch is affected by wind and photovoltaic variability, battery state-of-charge (SOC) dynamics, demand-response (DR) participation, and emissions from dispatchable generation. This paper proposes a low-carbon economic dispatch model for an islanded photovoltaic–wind-turbine–battery-energy-storage–dispatchable-generator–demand-response (PV-WT-BESS-DG-DR) microgrid. The objective includes fuel, operation and maintenance, BESS degradation, renewable curtailment, load shedding, DR compensation, and carbon-emission costs. A repair-based constraint-handling strategy keeps the search space continuous while enforcing power balance, DG ramping, BESS operating and SOC limits, terminal SOC, and DR constraints. An improved whale optimization algorithm (WOA) is then developed with three modules: diversity enhancement, exploration–exploitation balancing, and local escape and refinement. The method is assessed through base-case dispatch, benchmark comparison, strategy comparison, ablation tests, and sensitivity analysis. In 30 independent runs, the proposed method achieves a mean cost of 2662.96 CNY/day, 4.07% lower than standard WOA, and reduces the standard deviation by 79.72%. Wilcoxon and Friedman tests confirm significant differences from the benchmark algorithms. Sensitivity tests show that higher BESS degradation coefficients and carbon prices increase the accounting cost but do not change the qualitative feasibility of the deterministic dispatch framework. Full article

To address the issues of high energy consumption, high carbon emissions, and the waste of associated energy (AE) in coal mine production, which severely hinder global sustainable development goals, this paper proposes a novel low-carbon economic collaborative optimal scheduling model for a coal mine integrated energy system (CMIES) oriented towards sustainable energy transitions. First, a refined utilization model for AE encompassing coal mine gas, ventilation air methane (VAM), and mine groundwater (GW) is constructed, and a tiered carbon emission trading mechanism (TCET) is introduced to constrain carbon emissions and promote ecological sustainability. Second, a concentrated solar power (CSP) plant is integrated to break the rigid “power determined by heat” constraint of a traditional combined heat and power (CHP) unit, thereby enhancing the system’s scheduling flexibility and renewable energy integration. Meanwhile, abandoned mines are retrofitted into solvent storage tanks to construct an integrated flexible carbon capture system (IFCCS), achieving sustainable reuse of mining wastelands. Finally, to tackle the multi-source, heterogeneous uncertainties on both the source and load sides, a hybrid risk assessment method combining information gap decision theory (IGDT) and conditional value at risk (CVaR) is proposed. Case study results demonstrate that, compared to traditional energy supply modes, the proposed model reduces carbon emissions and total costs in the mining area by 66.04% and 15.97%, respectively. This significantly improves resource utilization efficiency and ecological benefits, providing a highly viable pathway for the sustainable development and clean transition of coal mine operations. Furthermore, the proposed hybrid assessment method can effectively assist decision-makers in achieving a refined trade-off between operating costs and system robustness under varying risk preferences. Full article

The greenhouse effect poses a severe environmental challenge to global sustainable development. Carbon emissions, as a major source of greenhouse gases, make their reduction a crucial goal of urban renewal. This paper provides a systematic literature review of over 100 empirical studies published in the Web of Science over the past decade. The results show that the impact of urban form on carbon emissions exhibits spatial heterogeneity and nonlinearity, while urban compactness reduces emissions in small and medium-sized cities but may increase emissions in some large mega cities. Meanwhile, three-dimensional morphological indicators (e.g., building height, sky view factor) exhibit a U-shaped effect on operational carbon emissions, and are primarily mediated by local microclimate effects. In addition, this study also summarized the differences in carbon emissions throughout the entire life cycle of urban renewal and across different climate zones. Only a few studies adopt a full life-cycle assessment, and most of them focused on operational rather than embodied carbon. This review credits itself as the first one of its kind to examine the relationship between urban form, urban function, and carbon emissions from the perspective of urban renewal, providing both theoretical reference and practical insights for low-carbon strategies. Full article

Conventional full-space heating systems waste massive fossil-derived energy on unoccupied indoor areas and cause uncomfortable “warm head, cold feet” issues against sustainable building targets. To fill this gap and advance low-carbon indoor heating solutions for sustainable office development, this study proposes an innovative localized heating terminal combining radiant panels and downward laminar air supply. An experimental platform was established, with twelve testing cases covering varied supply air velocity, supply air temperature and radiant panel temperature to explore its thermal comfort and energy-saving sustainability performance. Experimental results demonstrate that, under the optimal operating condition (0.55 m/s airflow, 23.5 °C supply air, 36 °C radiant panel), the vertical head–foot temperature difference reduces to merely 1.2 °C, far below the 3–5 °C threshold of conventional heating equipment; the draught rate approaches zero to eliminate cold draft discomfort. Critically, 65–75% of total supplied heat concentrates within human-occupied zones, drastically cutting redundant heat loss and advancing building heating sustainability. The terminal features dual working modes: convection contributes 78.7–94.4% of total heat for rapid warm-up while radiant heat maintains stable long-term comfortable surroundings. Such flexible dual-mode design supports sustainable part-load operation matching intermittent office occupancy, making this terminal a feasible low-carbon option for modern sustainable office buildings prioritizing energy efficiency and a healthy indoor environment. Full article

The assessment of the “Do No Significant Harm” (DNSH) principle in European Union (EU)-funded projects currently relies on narrative justification, which generates subjective evaluations, inconsistent results, and high administrative effort. This study aims to develop an operational framework and project-level tool to standardize how environmental impact is measured across multiple sectors and project types. The methodology applies a stepwise, non-compensatory approach, combining typology-based filtering, financial thresholds derived from carbon intensity and sustainability coefficients, checklists, spatial analysis, and quantitative indicators such as the circular economy transition metric. Each environmental objective is evaluated independently, ensuring that compliance cannot be offset by positive performance in other areas. The framework was preliminarily validated using a dataset of 1406 projects implemented in Romania, indicating its potential to distinguish low-risk from high-risk projects, reduce evaluator subjectivity, and improve the proportionality of analytical effort. While the tool is tested on Romanian case studies, its design allows for application across various European funding programmemes. The tool supports early-stage screening, encourages green procurement, and aligns project planning with EU environmental objectives, including climate mitigation, adaptation, water resource protection, pollution prevention, circular economy, and biodiversity conservation. The proposed methodology provides a clear, reproducible, and practical approach, offering evaluators a consistent mechanism for DNSH compliance verification and integrating environmental protection into project design and implementation. Full article

As urban energy demand increases and available roof space remains limited, balcony photovoltaic (PV) systems have emerged as a promising distributed renewable energy solution. This study aims to evaluate the multidimensional benefits of these systems in urban residential applications from a dual-carbon perspective. A combination of experimental tests and numerical simulations was used to investigate the effects of installation tilt angles and vertical self-shading in high-rise buildings. A comprehensive assessment model was constructed, integrating technical power generation gains, economic returns, and environmental carbon reduction benefits. The results demonstrate that when comprehensively balancing generation gains, economic viability, and structural safety, the practical optimal installation tilt angle for balcony PV systems is around 30°. The Levelized Cost of Electricity (LCOE) is calculated at 0.050–0.061 USD/kWh. Furthermore, a standard 800 W system operating under Beijing’s climate conditions can reduce carbon emissions by approximately 12.68 tons over its 25-year lifecycle. Therefore, balcony PV systems deliver significant technical, economic, and environmental benefits, serving as a highly feasible strategy to promote low-carbon and sustainable development in high-density cities. Full article

This study reframes street-level sustainable urban renewal as a coordination problem between street vitality and relative low-carbon performance, rather than treating vibrant activity and carbon-pressure reduction as separate planning objectives. Its main contribution is an integrated street-level diagnostic framework that combines multidimensional vitality measurement, township-constrained carbon-emission reference estimation, vitality–carbon mismatch identification, and interpretable nonlinear mechanism analysis within unified street analytical units. Although previous studies have substantially advanced the measurement of street vitality and urban carbon emissions, these two strands of research have often developed separately. As a result, limited evidence is available on whether high-vitality streets also perform well in low-carbon terms, where vitality–carbon mismatches emerge, and which built-environment conditions are associated with more coordinated outcomes. Taking the five central districts of Chengdu, China, as a case, this study integrates multi-source activity, mobility, built-environment, and emission-related data. Street vitality is measured through activity agglomeration, temporal continuity, functional support, and external connectivity, while relative low-carbon performance is derived from the reverse normalization of length-normalized carbon-emission intensity based on a township-constrained street-level emission reference estimate. The results show that street vitality and low-carbon performance are spatially uneven and frequently mismatched, as high activity does not automatically translate into stronger low-carbon performance, and lower-carbon pressure does not necessarily indicate a vibrant urban environment. More coordinated streets are associated with context-specific combinations of functional organization, transport operation, built form, street-interface quality, and ecological background. Nonlinear diagnostic results further suggest that coordination is favored by moderate, balanced, and locally adapted built-environment conditions rather than by the simple maximization of individual indicators. These findings shift the discussion from whether vitality and low-carbon performance are desirable in isolation to how they can be jointly diagnosed and improved in street-level urban renewal. Full article

This study investigates the influence of organic matter properties in surface waters on the efficiency of single- and two-stage coagulation processes in drinking water treatment plants. The research was conducted at three treatment plants supplied by different surface water sources over a 15-month monitoring period. The analyzed parameters included total and dissolved organic carbon (TOC and DOC), biodegradable dissolved organic carbon (BDOC), water color, UV absorbance, zeta potential, and molecular weight distribution of organic substances. The results showed that coagulation efficiency depends strongly on both the concentration and the molecular characteristics of organic matter. The highest removal efficiency was observed for high-molecular-weight fractions (>2.0 kDa), mainly humic substances, whereas low-molecular-weight compounds were removed less effectively. The study also demonstrated that surrogate spectrophotometric parameters, particularly UV₂₅₄ absorbance and color at 410 nm, can be used to monitor and optimize the coagulation process. Given the increasing frequency of extreme climate events and rapid shifts in raw water quality, optimizing single- and two-stage coagulation configurations has become an urgent operational necessity. This work provides a novel direct linkage between simple spectrophotometric indexes and precise chromatographic molecular ranges, delivering an immediate, high-impact predictive tool for real-time dosage optimization in water treatment engineering. Full article

Global climate governance is undergoing a rapid transformation, and energy systems are increasingly shifting toward low-carbon development. Against this background, improving manufacturing firms’ green total factor productivity (MFGTFP) is essential for achieving sustainable industrial development. China has introduced two major policy instruments: new energy demonstration cities (NEDCs) and low-carbon city pilots (LCCPs). NEDCs focus on optimizing the energy supply structure, whereas LCCPs seek to reduce carbon emissions through demand-side regulatory constraints. This study treated the joint implementation of NEDCs and LCCPs as a quasi-natural experiment and employed panel data from Chinese A-share listed manufacturing firms from 2007 to 2024. Using a multi-period difference-in-differences model and mechanism tests, we examined the effect of the joint implementation of these policies on MFGTFP. The empirical results show that the joint implementation of NEDCs and LCCPs significantly improves MFGTFP. This effect is more pronounced when NEDCs are introduced prior to LCCPs, particularly in cities with a higher government ecological governance capacity (GEGC) and in regions characterized by a lower carbon emission intensity (CEI). Mechanism analysis revealed that the joint effects of NEDCs and LCCPs operate through supply-side innovation and partially through demand-side cost-pressure channels. On the supply side, NEDCs promote green innovation (GI), thereby enhancing firms’ supply innovation. On the demand side, the evidence mainly reflects financing constraint (FC) alleviation rather than a positive capacity utilization (CU) channel. Together, these findings suggest that improvements in MFGTFP are driven by supply-side innovation incentives and partially by demand-side cost-pressure effects through FC alleviation. These findings provide firm-level evidence on how the joint implementation of energy and carbon policies promotes green productivity improvement. Full article

The transition toward more sustainable catalytic processes has driven increasing interest in waste-derived reducing agents and biomass-based carbon supports. In this study, silver nanoparticles (Ag NPs) were synthesized via conventional NaBH₄ reduction or through a bio-derived route using orange peel extract (OPE) and subsequently employed either as colloidal catalysts or immobilized on commercial activated carbon (AC) or coconut-derived carbon (CC). Catalytic activity was evaluated through the reduction of p-nitrophenol under pseudo-first-order conditions using UV–Vis spectroscopy. OPE-derived Ag NPs exhibited slightly higher activity than NaBH₄-reduced nanoparticles, while immobilization on carbon supports generally enhanced reaction rates, with Ag/AC_BH showing the highest kinetic constant. In contrast, CC-based systems displayed lower absolute activity but improved cost-normalized performance due to the lower cost of the support. A preliminary cost–performance analysis, based on direct material costs, suggested that catalytic efficiency trends can be significantly altered when economic factors are considered, highlighting that the most active system does not necessarily correspond to the most cost-effective one. Stability tests showed progressive deactivation over reuse cycles, mainly attributed to surface oxidation and/or poisoning phenomena. These results demonstrate that integrating waste-derived reagents with low-cost supports can provide competitive catalytic systems, although further optimization is required to improve their long-term operational robustness. Full article

Against the backdrop of global green and low-carbon energy structural transition, renewable energy represented by photovoltaic power has emerged as a critical strategy for safeguarding energy security and mitigating climate change. As typical energy-intensive infrastructures, wastewater treatment plants (WWTPs) suffer from excessive energy consumption and substantial carbon emissions. In this study, a distributed photovoltaic power generation system is deployed at WWTPs to alleviate on-site power demand, and its economic and environmental benefits are quantitatively analyzed via PVsyst software simulation. The simulation results indicate that the overall system efficiency reaches 83.3%, with an annual average power generation capacity of 825,500 kW·h. Annually, the proposed system can save 275.17 tons of standard coal, and correspondingly reduce carbon dioxide emissions by 687.92 tons, sulfur dioxide emissions by 20.64 tons and nitrogen oxide emissions by 10.32 tons, thereby realizing synergistic enhancement of economic and environmental performances. This work offers a feasible engineering reference for promoting the modernized transformation of WWTPs toward energy self-sufficiency and low-carbon operational modes. Full article