Search Results (2,073)

The escalating production of sewage sludge presents a significant environmental challenge, while the construction industry simultaneously seeks sustainable raw materials to improve its circularity. This review analyses the technical and regulatory landscape for valorizing SS within the Latvian construction sector, set against the divergent strategies of its Baltic neighbours. While global research confirms the technical viability of using SS in fired-clay bricks and as a supplementary cementitious material (SCM), national management approaches differ starkly. Lithuania has adopted widespread incineration, and Estonia has focused on advanced composting. In contrast, Latvia’s national strategy is failing, with 51% of its 2024 sludge production diverted to “temporary storage”. This review identifies this crisis as a unique opportunity, arguing that incorporating dewatered digestate into fired-clay bricks is the most logical and economically viable pathway for Latvia, as it leverages existing industrial infrastructure. The primary obstacle to this circular solution is not technical but legal, specifically the lack of a national “End-of-Waste” (EoW) criterion for sludge-derived construction materials. Therefore, this article proposes a strategic roadmap for Latvia, centred on developing this essential legal framework, creating a national sludge characterization map, and initiating a pilot project to bridge the research-to-industry gap. Although Latvia is the primary focus of this review, the regulatory, infrastructural and material constraints analysed here are common in many small and mid-sized countries, making the insights applicable beyond the Latvian context. Full article

Carnot batteries based on the coupling of high-temperature heat pumps (HTHPs) and Organic Rankine Cycles (ORCs) emerge as promising solutions for large-scale and long-duration energy storage, enabling sector coupling and the valorization of industrial waste heat. In such systems, the charging subsystem plays a dominant role, as variations in heat pump performance influence the round-trip efficiency more strongly than comparable variations in the ORC. This work presents a thermodynamic assessment of Rankine-based HP–ORC Carnot batteries focusing on the influence of heat pump configuration and working fluid selection. System performance is evaluated using the heat pump coefficient of performance, volumetric heat capacity, ORC efficiency, and Carnot battery round-trip efficiency through a grid-search optimization over a wide range of storage outlet and waste heat source temperatures. The results show that single-stage configurations are optimal at low to moderate temperature lifts, while two-stage and cascade systems become advantageous at higher lifts. Among the investigated fluids, R-601 provides the highest round-trip efficiencies at elevated storage temperatures, whereas R-600 enables more compact systems due to its higher volumetric heat capacity. These findings provide design guidance for selecting heat pump configurations and working fluids in industrial waste-heat-assisted Carnot battery applications. Full article

Internet-of-Things (IoT) sensing can improve traceability, safety, and efficiency of medical waste handling, yet many deployments remain fragmented, lack an end-to-end system architecture, and do not provide the structured data pipelines needed for artificial intelligence (AI) analytics. This paper presents a layered IoT-based system design for medical waste management that integrates: (i) Espressif Systems 32 (ESP32)-based edge devices for fill-level and Global Positioning System (GPS) telemetry; (ii) secure network communication; (iii) a cloud backend for data ingestion, storage, and analytics; and (iv) operator dashboards with event-driven alerting. The architecture extends our prior GPS-enabled tracking and route optimization by adding sensor-driven state monitoring, threshold-based decision support, and a time-series data pipeline designed for future AI-driven predictive analytics. In a 30-day pilot with five containers, the system collected one reading every 15 min (14,400 total readings). The backend demonstrated efficient processing with an average Application Programming Interface (API) response time of 45 ms, sub-50 ms database write latency, and high uptime; alerts were delivered promptly upon threshold violations. Compared with a fixed-schedule baseline, the system enabled condition-based collection scheduling with zero data loss. The proposed design emphasizes modularity, fault tolerance, and integration readiness for hospital information systems, providing a practical blueprint for scalable smart-healthcare waste logistics and a foundation for machine learning-based predictive waste management. Full article

Supercapacitors (SCs) are highly attractive energy storage devices, and modern research is focused on using waste materials to reduce environmental impact. This study processed biowaste from local brewery production to produce a highly specific mesoporous activated carbon (AC) for SC electrode scaffolds. Polyaniline (PANI) was synthesized and incorporated into the AC scaffold, thereby enhancing performance. The AC and PANI combination (ACP) achieved a specific capacitance of 173.7 F/g at 1 A/g, with 92% retention after 5000 cycles. Using NdFeB (ACN) particles, the anode showed a specific capacitance of 127 F/g and over 99% retention. An asymmetrical ACN//ACP cell demonstrated promising performance with 70% efficiency. This study highlights the potential of using biowaste for high-performance SC electrodes and the effective synergy between AC and PANI. Full article

In this study, the potential for re-mixing and re-vulcanizing waste natural rubber glove (WNRG) material by using it as the primary matrix was investigated. Alternative types of vulcanization systems, namely, sulfur, phenolic resin, and peroxide, were employed. The results unequivocally demonstrated that residual vulcanizing agents contained in the WNRG were not sufficient to cause crosslinking reactions without re-mixing with vulcanizing agents. Among the various vulcanization approaches, sulfur produced the greatest properties, whereas phenolic resin gave moderate performance. The WNRG vulcanized with sulfur demonstrated the highest crosslink density, tear strength, tensile strength, hardness, and strain-induced crystallization ability among the tested alternatives. The tensile strength of WNRG vulcanized with sulfur was approximately 16.23 MPa, which was 31.7% and 51.1% greater than the WNRG vulcanizates made with phenolic resin and peroxide, respectively. Because of its highest crosslink density, the WNRG vulcanizate with sulfur also offers the greatest storage modulus among the tested cases. The results clearly suggest that the WNRG can potentially be re-compounded, re-vulcanized, and used as the primary matrix. WNRG could be used as a matrix at an industrial scale, to minimize the environmental issues and increase the added value from waste gloves. The findings provide practical guidance for recycling waste rubber gloves in industrial applications, which would be a more sustainable solution for solving the problems associated with WNRG. Full article

Rice straw as a growth substrate for soilless sod production not only avoids the damage to farmland soil deterioration but also solves the difficulty in disposing of a large amount of agricultural straw waste. This study was designed to explore the feasibility of using rice straw as a soilless sod production for seashore paspalum. The results showed that both fermented rice straw and raw rice straw significantly promoted the creeping growth and tillering of seashore paspalum, shortening the sod production period, when compared to the conventional soil sod. Rice straw sod significantly reduced sod weight to 50% and 52% of the soil sod, but increased sod strength to avoid tear damage in handling and transportation. Rice straw sod had 2 d longer shelf life than the soil sod, with slower decline of sod quality and maintained higher root and leaf emergence vigor during the sod storage. After sod installation, rice straw sod showed higher numbers of root and leaf emergence, and higher green leaves, stolons, new roots, aboveground and underground biomass, but lower thatch biomass, compared to the soil sod. Our results demonstrated that using rice straw as a growth substrate to produce soilless sod is feasible and significantly better than conventional soil sod production. Full article

Waste heat capture and reuse from battery storage systems for cogeneration of heat and power has the potential to both improve their energy efficiency and reduce the carbon footprint. This study performs a comparison of technologies capable of converting the waste heat extracted to a useful purpose. This analysis is accomplished using the literature data as a basis for an analytical hierarchy process (AHP) applying technological efficiency, cost effectiveness, footprint and integration, and safety and environmental concerns as the criteria. Of these, cost effectiveness was found to be dominant, with technological efficiency also showing high importance. Heat pumps were found to be the most effective based on the objective and criteria of this analysis. This study dictates a pathway that allows stakeholders and decision makers to determine a route by which site-specific comparisons may be made, aiding them to navigate the complex interplay of competing objectives. Full article

This study examines the carbonation behavior and CO₂ storage potential of a Ca-rich alkali-activated binder produced entirely from industrial residues-ladle furnace slag (LFS), coal ash (CA), and cement kiln dust (CKD). The system was designed as a one-part alkali-activated material (AAM), with CKD acting as an internal activator, and subjected to ambient curing, water curing, and accelerated CO₂ curing at ambient pressure. Phase evolution, microstructural development, and pore-structure characteristics were investigated using X-ray diffraction, FTIR spectroscopy, DSC–TG analysis, scanning electron microscopy, and X-ray micro-computed tomography, together with measurements of density, water absorption, and compressive strength. Loss-on-ignition measurements combined with chemical analysis were further used to quantify CO₂ uptake and evaluate the degree of carbonation of the binder system. CO₂ curing fundamentally altered the reaction pathway of the binder, shifting it from hydration-dominated to carbonation-controlled phase evolution, leading to the decomposition of calcium-bearing hydrates and complete carbonation of non-hydraulic γ-belite with the formation of vaterite, aragonite, and calcite. These transformations induced pronounced microstructural densification, reflected in a near-doubling of compressive strength (>48 MPa), increased apparent density, reduced water absorption, and simplified pore-network topology. A preliminary carbon footprint assessment indicates that the production of 1 m³ of the developed LFS–CA–CKD concrete generates about 14.36 kg CO₂-eq, while the carbonation process enables significant CO₂ sequestration, resulting in a net negative carbon balance. The results demonstrate that controlled carbonation is an effective post-treatment strategy for waste-derived alkali-activated binders, enabling simultaneous performance enhancement and permanent CO₂ sequestration. Full article

Global data center electricity demand is projected to double to 945 TWh by 2030, yet no optimization framework jointly sizes renewable generation, battery storage, hydrogen export infrastructure, and flexible computing loads within a single industrial hub. This paper develops a two-layer techno-economic workflow for an integrated renewable–hydrogen–data center hub in Yanbu Industrial City, Saudi Arabia. HOMER Pro provides baseline capacity sizing and dispatch across four scenarios; a Pyomo-based mixed-integer linear program, calibrated to within 2% of the baseline, then extends the system to include a 60 MW data center (30 MW critical, 30 MW flexible), multi-sink hydrogen allocation (domestic, ammonia, methanol), and low-grade waste heat recovery. Battery storage emerges as the dominant cost–carbon lever: its removal raises the levelized cost of electricity (LCOE) from 0.052 to 0.181 USD/kWh (+250%) and increases CO₂ emissions from 1.83 to 2763 kt/yr, a factor of 1510. The Integrated Hub reduces annualized costs by 8.2% (36.9 M USD/yr) and emissions by 28% relative to a separate-build counterfactual, driven by shared PV–battery infrastructure and hydrogen export revenues of 58.5 M USD/yr. Export demand raises the electrolyzer capacity factor from 8.65% to 24.3%, cutting the levelized cost of hydrogen from 10.5 to 6.8 USD/kg. Waste heat recovery reduces the levelized cost of heat by 17%, and co-location lowers the levelized cost of compute by 23% (from 0.055 to 0.042 USD/GPU/hr). These results provide quantitative design principles for industrial hub planners considering data center co-location in high-solar regions with hydrogen export ambitions. Full article

The water–energy–carbon (WEC) nexus provides a systems framework for minimizing trade-offs among water security, energy reliability, and carbon mitigation. Within this framework, waste-derived biochar catalysts offer a circular pathway that simultaneously valorizes residues, reduces process energy demand, and supports carbon management through stable carbon storage and catalytic co-benefits. This review consolidates recent advances in biochar-based catalysts engineered from agricultural, industrial, municipal, and sludge-derived wastes, highlighting how feedstock selection and thermochemical processing, namely pyrolysis, hydrothermal carbonization (HTC), and torrefaction, as well as activation and post-modification (heteroatom doping and metal/metal-oxide incorporation) govern structure–property–performance relationships. The synthesized catalysts have been widely applied in water and wastewater treatment, including adsorption–advanced oxidation process (AOP) hybrids, Fenton-like systems, peroxydisulfate/persulfate (PS) and peroxymonosulfate (PMS) activation, photocatalysis, and the removal of emerging contaminants. They have also demonstrated strong potential in energy conversion processes such as the hydrogen evolution reaction (HER), oxygen reduction and evolution reactions (ORR/OER), biomass reforming, and carbon dioxide (CO₂) conversion. In addition, these materials contribute to carbon management through sequestration pathways, avoided emissions, and life cycle assessment (LCA)-based sustainability evaluations. Finally, we propose a WEC-aligned design roadmap integrating techno-economic analysis (TEA), LCA, and scale-up considerations to guide next-generation biochar catalysts toward robust performance in real matrices and deployment-ready systems. Full article

Thermochemical heat storage technology serves as an effective approach for efficient recovery and cross-seasonal storage of low-grade waste heat. However, traditional packed-bed heat exchange methods in industrial applications are prone to material contamination and performance degradation due to impurities in waste heat gases. To address this, this study proposes and constructs a thermochemical heat storage system based on moving-bed indirect heat exchange, using magnesium sulfate heptahydrate (MgSO₄·7H₂O) as the heat storage medium. The system investigates its desorption and heat storage characteristics within the moving bed. A small-scale moving-bed experimental platform was established, incorporating a vacuum-assisted system to promptly remove water vapor generated during desorption. The experimental system examines the effects of different operating parameters (e.g., inlet water temperature and flow rate) on particle temperature fields, desorption rates, and overall heat transfer performance. Results demonstrate that MgSO₄·7H₂O exhibits excellent heat storage stability and reaction controllability in the medium-low temperature range (60–95 °C). Increasing inlet water temperature and flow rate enhances desorption processes, but high temperatures also lead to increased temperature gradients, reducing waste heat recovery rates. Practical applications require optimizing the balance between heat transfer enhancement and desorption time. Compared to conventional heat storage particles, the moving-bed system using magnesium sulfate heptahydrate achieves approximately 30% higher overall heat transfer coefficient. Compared to traditional packed beds, the moving-bed heat exchange method demonstrates superior heat transfer uniformity and storage efficiency. This study validates the feasibility of the “moving-bed + thermochemical heat storage + vacuum desorption” technology under non-clean heat source conditions, providing experimental evidence and technical references for efficient industrial waste heat recovery and high-density storage. Full article

Waste sweet potato vine fiber (WSVF) effectively extends asphalt service life by enhancing cracking resistance in gel-like base asphalt matrices, yet its crack-resistant mechanism lacks mechanical characterization. This study proposes an analytical method for evaluating WSVF-modified asphalt’s crack-resistant behavior based on the principle of mechanical energy balance. First, alkali-treated WSVF with a mass fraction of 1% was added into 70# gel-like base asphalt to prepare WSVF-modified asphalt. Lignin fiber (LF)-modified asphalt and 70# gel-like base asphalt were selected as control groups, and three types of time sweep and scanning electron microscopy tests were conducted. Then, the three-dimensional cracking volume model and damage kinetics model were established for analyzing the cracking response behavior, defining the asphalt damage variable and determining the cracking damage activation energy (E_acd). Finally, the E_acd was used to quantify the difficulty of the cracking damage process for the WSVF-modified asphalt. The reinforcement and cracking resistance mechanisms of WSVF in asphalt were analyzed by the E_acd and asphalt microstructure. The results show that the cracking volume response of WSVF-modified asphalt under cyclic loading presents three-stage nonlinear behaviors. The established fatigue damage kinetics model can accurately describe the fatigue damage evolution process of alkali-treated WSVF-modified asphalt. The E_acd values of WSVF-modified asphalt, LF-modified asphalt, and 70# gel-like base asphalt are 10.60 kJ·mol⁻¹, 21.83 kJ·mol⁻¹, and 29.74 kJ·mol⁻¹, respectively. After alkali treatment, the WSVF surface exhibits grooves, demonstrating superior adsorption and storage capacity for asphalt. The WSVF can cross link through the bonding effect of asphalt and form a three-dimensional network framework structure, which can significantly increase the E_acd and provide strengthening and toughening effects on gel-like base asphalt. In summary, E_acd values are used as a mechanical indicator to quantitatively evaluate the fatigue cracking resistance of WSVF-modified asphalt. Full article

In developing countries, where rural communities face limitations in terms of solid waste management (SWM), they often resort to practices such as prolonged storage and open burning. Proper planning helps reduce environmental, health, and economic impacts and moves towards more sustainable waste management. This study analyses SWM in the rural community of Sahuangal (Ecuador) and proposes a pilot management plan based on community participation. A three-phase methodology was applied: (i) preliminary analysis, surveys, and Strengths, Weaknesses, Opportunities and Threats (SWOT-TOWS) analysis; (ii) infrastructure design for the pilot plan, integrating the physical characterisation of waste for infrastructure sizing; (iii) economic- and financial evaluation and multicriteria prioritisation using the Analytic Hierarchy Process (AHP). The survey results indicate that 75.86% of households reported a predominance of organic waste, whereas the pilot-level characterisation conducted in a typical household identified an organic fraction of 69.81%. The SWM pilot plan is cost-effective and, by relying on small-scale infrastructure built with local materials and community labour, incorporates social and environmental sustainability criteria. The combination of SWOT-TOWS analysis with AHP emphasised community participation, the viability of composting, and the recovery of recyclables as the predominant criteria, suggesting that the plan can be adapted to other rural communities with similar conditions. Full article

Processes for generating clean hydrogen from waste plastics through thermochemical methods such as pyrolysis and gasification are a promising solution for both waste management and clean energy initiatives. Then, this derived hydrogen powers the fuel cell, which produces electricity that can be directly fed to charge electric vehicles (EVs). Although this complex process has many challenges related to energy efficiency during the conversion processes—starting from the generation of hydrogen from thermochemical processes and hydrogen storage and followed by fueling the fuel cells and charging EV infrastructure—the simplistic conceptual modeling developed for this research demonstrates how an ecosystem of such processes can be made feasible commercially. Clean hydrogen generated using known techniques reported in the literature is promising for commercialization, but harnessing hydrogen from plastics offers additional benefits, such as reducing greenhouse gas (GHG) emissions. Overall, the feasibility of clean hydrogen using this methodology is not limited by potential cost inefficiencies, especially when savings from GHG emissions reduction are taken into account. EVs have become commercially viable thanks to high-energy-density Li-ion batteries. And therefore, research continues to optimize charging performance through the integration of renewable energy and battery storage systems. This study examines another potential of clean hydrogen: its use as a power source in grids, especially V-2-G (vehicle-to-grid) systems. Additionally, direct current (DC) power from a fuel cell powers an EV charger at DC input voltages for e-ambulances. In particular, this designed system operates on DC voltages throughout the power system, combining high-voltage direct current (HVDC) lines, renewable energy sources, DC-DC converters, DC EV chargers, and other supporting components. The literature review identified gaps in plastics production, waste management, and processes for converting them into useful energy. The presented model is a stepping stone towards a novel, innovative process for clean hydrogen production to power electric vehicle charging infrastructure for emergency response systems in healthcare, thereby improving public safety. The limitations of the study would be governed by the effective establishment of locations where waste management services are performed (for example, landfills) and adoption by local government authorities with deregulated power systems. Full article

Despite timber’s strategic role in the circular economy, its application in Türkiye remains negligible compared to the rigid reinforced concrete (RC) housing stock, which limits flexibility and penalizes the environment. This study investigates the adaptability and environmental performance of modular timber construction via a 17-year longitudinal case study in Seferihisar, İzmir. Using architectural observation, user interviews, 3D BIM, and a comparative LCA, findings reveal the structure successfully accommodated a six-phase functional transformation—the structure’s gross floor area increased by 6.19 times more (from 21 m² to 151 m²) and bed capacity from 2 to 18—with virtually zero demolition waste through dry-assembly techniques. Crucially, normalized LCA proves timber’s ecological superiority: achieving an embodied energy intensity of 6.60 GJ/m² (1.2 times less than the RC equivalent’s 7.97 GJ/m²). Furthermore, biogenic carbon storage enabled the timber dwelling to reach a negative Global Warming Potential (GWP) of −26,118.39 kgCO₂ (a carbon sink), whereas the RC model emitted +39,081.22 kgCO₂. Given that secondary housing predominantly comprises two-story structures, lightweight timber sustainably meets this typological demand. Ultimately, user-driven modular timber presents a resilient, eco-efficient, circular economy model for second-home and post-disaster settlements. Full article