Search Results (25,478)

Excess phosphorus (P) and nitrogen (N) in wastewater contribute to eutrophication, driving the need for low–cost and sustainable recovery technologies. This study presents a novel adsorbent synthesized from spent coffee grounds biochar (CB) chemically modified with Mn²⁺/Zn²⁺/Fe³⁺ (oxy)hydroxide nanoparticles (CB–M) for simultaneous removal of phosphate and ammonium. Batch adsorption experiments using both synthetic solution and municipal wastewater were conducted to evaluate the material’s adsorption performance and practical applicability. Kinetic, isotherm, thermodynamic, and sequential extraction analyses revealed that CB–M achieved maximum phosphate adsorption capacities ranging from 42.6 to 72.0 mg PO₄³⁻·g⁻¹ across temperatures of 20–33 °C, reducing effluent phosphate concentrations to below 0.01 mg·L⁻¹. Ammonium removal was moderate, with capacities ranging between 2.8 and 2.95 mg NH₄⁺·g⁻¹. Thermodynamic analysis indicated that phosphate adsorption was spontaneous and endothermic, dominated by inner–sphere complexation, while ammonium uptake occurred primarily through weaker, reversible ion exchange mechanisms. Sequential extraction showed over 70% of adsorbed phosphate was associated with Fe-Mn-Zn phases, indicating the potential for use as a slow–release fertilizer. The CB–M retained structural integrity and exhibited partial desorption, supporting its reusability for nutrient recovery. Compared to other biochars, CB–M demonstrated superior phosphate selectivity at a neutral–pH, avoided the use of hazardous metals, and transformed coffee waste into a multifunctional material for wastewater treatment and soil amendment. These findings underscore the potential of CB–M as a circular economy solution for nutrient recovery without introducing secondary contamination. Full article

This study explored the feasibility of the carbon-free smelting of ferrochrome (FeCr) using a complex reducing agent—ferroaluminosilicalcium alloy (FeAlSiCa)—produced from industrial waste and ferrosilicochrome (FeSiCr) dust. Laboratory-scale smelting experiments were conducted with Cr concentrate and the addition of FeAlSiCa and FeSiCr dust under four different reducing agent contents: (1) 10% deficiency, (2) stoichiometric amount, (3) 10% excess, and (4) 20% excess. It was found that with a 10% excess, a nearly complete reduction of Cr₂O₃ was achieved (residual content in slag ≤ 0.9%), resulting in the formation of low-carbon FeCr (LC FeCr) with a high nitrogen content (up to 2.6%). Based on a thermodynamic analysis of the reduction reactions, the high reactivity of the FeAlSiCa and FeSiCr components (Ca, Al, and Si) at 1500 °C was confirmed. These reactions were exothermic, which demonstrates the energy efficiency of using these ferroalloys as reducing agents in FeCr smelting. The resulting slag is structurally stable and does not disintegrate over time, making it a promising candidate for potential reuse as a secondary raw material. The results demonstrate the promise of the proposed technology for both reducing the carbon footprint of ferroalloy production and lowering the cost of the metallothermic production of LC FeCr. Full article

Micro-, small-, and medium-sized enterprises (MSMEs) have the opportunity to increase resource efficiency, decrease waste, and promote sustainability by implementing remanufacturing techniques. However, determining whether MSMEs are prepared for the adoption of such techniques requires a methodical approach that considers several aspects of manufacturing readiness, such as core acquisition, the design of remanufacturing, and others. Therefore, this study proposes a framework to measure the readiness for the adoption of remanufacturing practices. Further, the remanufacturing readiness index (RRI) is proposed by combining remanufacturing indicators with a structural approach based on graph theory and matrices (GTM). Nine remanufacturing readiness attributes are identified through the literature and validated by an expert team. These nine attributes include core acquisition, reverse logistics availability, resource availability for remanufacturing initiatives, the design for remanufacturing, enterprise collaboration, remanufactured product positioning, performance measurement, labor skill and availability, and a flexible remanufacturing system. The finalized remanufacturing readiness attributes are modelled using GTM to explore their interdependencies, forming the basis for a quantitative index (RRI) that reflects MSMEs’ readiness for the adoption of remanufacturing. It is used to measure the possibility of MSMEs implementing remanufacturing processes. To illustrate the efficacy of the RRI, a case study of a remanufacturing facility was conducted. This RRI acts as a decision-support tool to help MSMEs, industry stakeholders, and governments identify priority areas for intervention, promote resource efficiency, and create sustainable growth. The results highlight the importance of readiness attributes as fundamental components in implementing remanufacturing practices at the MSME level. Full article

This article examines urban mining in Brazil, highlighting its unique context compared to other regions. While European Union focuses on critical metal supply and advanced Waste Electrical and Electronic Equipment (WEEE) legislation and circular economy, Brazil’s urban mining is primarily driven by waste management and social inclusion. The current investigation was underpinned by the PRISMA extension for Scoping Reviews (PRISMA-ScR framework), using targeted searches on the Web of Science platform for technological processes and the Brazilian scenario, complemented by an analysis of legislative evolution and a Critical Discourse Analysis of national policies. The results indicate that, despite advanced legislation, significant gaps exist between discourse and practice, highlighting the need for technological appropriation, specific public policies that incentivize reverse logistics and the integration of the informal sector, and overcoming infrastructural challenges. It concludes that Brazil has a unique opportunity to develop an urban mining model that pioneeringly integrates environmental sustainability, technological innovation, and social inclusion, demanding coordinated efforts to overcome existing barriers. Full article

Sugarcane bagasse (SCB), an organic waste generated during sugar and ethanol production, is a potential biomass source with a high cellulose content. In this study, cellulose was extracted from SCB using a hydrothermal method with various types of solvents, following which the extracted materials were used for food container production. An alkali solvent—sodium hydroxide (NaOH)—and organic acids—citric acid and formic acid—were included as extractive solvents at two different concentrations (0.25 M and 2.0 M). Hydrothermal extraction with the alkali solvent demonstrated higher cellulose extraction abilities (67.7–74.0%) than those with the acids (52.5–57.3%). Using a low alkali concentration in the hydrothermal extraction (H-NaOH_low) demonstrated a cellulose extraction ability near that when using a high alkali concentration in the conventional boiling method (B-NaOH_high): 67.7% and 70.5%, respectively. Moreover, cellulose extracted with H-NaOH_low had better mechanical properties than that from B-NaOH_high, likely due to fewer defective fibers in the former. A high alkali concentration led to vigorous reactions that damaged the cellulose fibers. Thus, hydrothermal extraction has the benefit of using fewer chemicals, leading to a lower environmental impact. In addition, H-NaOH_low fibers were employed for food container production, and it was found that the obtained product has excellent properties, comparable to those of commercial containers. Full article

Apatite pastes derived from eggshell waste (BAp) were implanted onto the calvarial bone of rats, and bone formation was evaluated using X-ray μ-computed tomography (CT) and histological evaluation. BAp was mixed with distilled water to prepare a paste. Monoclinic hydroxyapatite of mineral resources (HAp) was used as a control. A 5 mm diameter PTFE (polytetrafluoroethylene) tube was filled with apatite pastes and implanted in the calvarial bone of 9-week-old Sprague Dawley rats for 8 weeks. A larger radiopaque area, similar to that of native bone, was observed in the BAp paste-implanted specimens than that of HAp paste. The bone mineral density (BMD) value of the BAp paste was significantly higher than that of the HAp paste (p < 0.05). In the histological evaluation, new bone formation was noticed from the calvarial side for both apatite specimens, and HAp remained in the PTFE unlike BAp. The bone mass (BM) value of the BAp paste was significantly higher than that of the HAp paste (p < 0.05). SEM and XRD analyses revealed that BAp was microcrystalline and poorly crystalline. The promotion of new bone formation may contribute to the crystallinity and Mg content of BAp. BAp was found to be useful as a bone regeneration material. Full article

The meat industry is one of the main sources of organic waste in the food processing sector. Due to their high content of biodegradable organic matter, these wastes represent a potentially valuable resource for the development of recycling and valorization processes, particularly with regard to the circular economy and environmental sustainability. The present study aimed at assessing the potential of natural sheep casings waste (NSCW) as a source of nitrogen for promoting the growth and lipid production of Scenedesmus rubescens MDP19, a marine microalga isolated from the Mediterranean coastline of northern Morocco. For this purpose, we evaluated the effects of different NSCW concentrations (0.25–5 g L⁻¹) on the microalga growth, its ability to utilize organic waste components (proteins, amino acids, and carbohydrates) as nutrients, and its efficiency in eliminating nitrogen and phosphorus. Lipid and pigment contents were determined using colorimetric methods, and their composition was analyzed by high-performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS/MS). The results showed that S. rubescens MDP19 achieved the highest biomass production of 1.737 g L⁻¹ at an NSCW concentration of 5 g L⁻¹. This strain removed 33.70–47.63% of protein, 71.84–87.62% of amino acids, 41.9–92.97% of carbohydrates, 59.72–99.30% of nitrogen, and 80.74–99.10% of phosphorus. Furthermore, S. rubescens MDP19 showed a significantly enhanced lipid content (68.11%) at an NSCW concentration of 0.5 g L⁻¹. At this concentration, the lipid composition of S. rubescens MDP19 was particularly complex, including monounsaturated and polyunsaturated fatty acids, digalactosyldiacylglycerols, sulfoquinovosyldiacylglycerols, phosphatidylglycerols, and acylglycerols. The pigment profile includes neoxanthin, canthaxanthin, lutein, chlorophyll a, geranylgeranyl chlorophyll a, chlorophyllide b, hydrochlorophyllide b, and pheophytin a. These results indicate that natural sheep casings waste represents a promising source of nitrogen, reducing the need for nutrient supplementation in microalgae production. This approach not only offers a sustainable and economical alternative for optimizing microalgae cultivation but also contributes to the valorization of organic waste, thus supporting more ecological and responsible practices. Full article

Cement production is a major contributor to CO₂ emissions, while construction and demolition waste (CDW) presents growing environmental challenges. The new European standard UNE-EN 197-6 permits the use of recycled concrete fines as partial clinker replacements, providing a regulatory framework for integrating CDW into cementitious systems. This study investigates two CDW-derived fillers, FHH (recycled concrete filler) and FHC (recycled ceramic–concrete mixed filler), as partial substitutes for ordinary Portland cement (OPC). The materials were characterized using XRD, XRF, FTIR, and particle size analysis. Cement pastes and mortars with 10%, 20%, and 30% volume replacements were evaluated for hydration behavior, mechanical performance, and durability. At lower replacement levels, FHC promoted ettringite formation and microstructural refinement, while FHH favored carbonate hydrate development; both fillers also exhibited durability comparable to the control. At higher levels, they maintained satisfactory compressive strength. This study offers critical insights into the integration of CDW-derived fillers into cementitious systems, revealing their potential to significantly reduce clinker consumption while maintaining high mechanical and durability standards. Full article

Malting is one of the most energy-intensive stages in beer brewing, yet its environmental impacts remain under-characterized despite recent efficiency gains. Barley and malt transport drive significant greenhouse gas emissions in import-dependent countries, while local, small-scale production can offset those savings through lower process efficiencies or higher resource use. This study conducted a cradle-to-gate Life Cycle Assessment (LCA) of three Italian malthouses—small, medium, and large—using SimaPro 10.2.0.0 and a functional unit of 1 kg of malted barley delivered by bulk truck to local breweries. Primary data on barley, water, methane, and electricity consumption, as well as waste generation, were collected via questionnaires; secondary data were sourced from Ecoinvent and Agri-Footprint. Impact categories were evaluated using the Cumulative Energy Demand (CED) and Product Environmental Footprint (PEF) methodologies. Barley cultivation dominates the footprint (84–92% of total impacts when using local grain). Drying and transport contribute 3.7–4.4% and 0–8.4% of impacts, respectively, depending on facility scale and import share. Smaller malthouses exhibit higher per-kilogram impacts due to lower energy efficiency and transportation modes. Mitigation strategies —including sustainable agriculture, renewable energy adoption, logistics optimization, and process improvements—can substantially reduce impacts. Notably, sourcing barley from low-impact suppliers alone lowers the carbon footprint from 0.80 to 0.66 kg CO_2e/kg, freshwater eutrophication from 227 to 32 CTU_e/kg, land use from 196 to 136 Pt/kg, and overall PEF from 192 to 81 µPt/kg. These results underscore the critical role of feedstock sourcing and process efficiency in decarbonizing malt production and provide a quantitative baseline for targeted sustainability interventions. Full article

The recovery of waste from old vehicles generates different types of waste. Most waste can be recovered with more or less success. Among the wastes that are problematic is foam. It is large in volume and light in weight, and there is currently no highly efficient technology to recover this waste and produce new products. The aim of this paper is to analyse the current situation in the processing, research, development, design and testing of test samples as a basis for the production of a machine to produce new 3D products made from waste foam. The paper begins with an analysis of the amount of plastic waste generated in the automotive industry. It describes the current state of waste management and the possibilities of its use in the production of new products. The core of the paper is the selection of suitable technology and the design and verification of experimental measurement and evaluation of test samples at different temperatures and pressures and with different endurance times. Full article

To facilitate the adoption of a food safety standard by producers, it is essential to understand their perception of it. However, few empirical studies have examined how livestock farmers perceive food safety standards in Vietnam. This research examines sheep farmers’ attitudes towards Vietnamese Good Agricultural Practices (VietGAP), a type of a food safety standard in Vietnam. A sample size of 109 farmers was selected for interviews and a structured questionnaire was generated to collect data. Descriptive and bivariate analyses were employed. The study results show that sheep farmers were well aware of most VietGAP requirements. They perceived that adopting VietGAP requires practical changes in sheep farming systems, including: selecting breeding stock from clear sources to ensure sheep product traceability, collecting and treating wastes daily to protect the environment, and frequent sterilization of sheep cages. The farmers were changing several practices to comply with VietGAP. Key changed practices identified included: bought breeding stock from clear and reliable sources, frequent collecting and treating of sheep wastes, and used veterinary medicine according to instructions of veterinary medicine producers. Statistically significant relationships existing between the sheep farmers’ perceptions and their education level (Pearson = 0.229, p = 0.017), farm size (Pearson = −0.193; p = 0.049), gender (Eta = 0.173, p = 0.060), practice of using labours (Eta = 0.202, p = 0.028), training participation (Eta = 0.211, p = 0.022), credit participation (Eta = 0.177, p = 0.050), community-based organisations (Eta = 0.153, p = 0.087), and veterinary/extension contacts (Eta = 0.217, p = 0.019) were found. This means that a male sheep farmer who had a higher education level, possessed a smaller farm, practiced hired labours, participated in training/credit programs, was a member of community-based organisation, and had contacts with veterinary/extension workers likely perceived VietGAP better than their counterparts. Based on the findings of this study, it is recommended that the promotion of VietGAP for livestock farmers should be developed and carried out as joint attempts along the value chain actors. New food marketing practices and legal framework and policy for using safe food certifications are required to address to promote farmers’ adoption of VietGAP and facilitate transition towards a sustainable agri-food system in Vietnam. This study provides significant insights into safety food standard adoption by livestock farmers and highlights aspects that require to be considered when developing policies to improve the adoption of safety food standards in developing countries. Full article

Carbon mineralization has attracted great interest as a promising strategy to achieve a decarbonized pathway by 2050. Despite the significant environmental and economic promise associated with using industrial solid waste for carbon mineralization, the scale-up application of this approach is limited due to its low reactivity and relatively high cost. A clear understanding of the detailed mechanisms governing various carbonation techniques is needed to achieve high CO₂ conversion efficiency. This review can provide valuable insight into carbon mineralization pathways, advantages and challenges, and potential feedstocks. Factors affecting reaction kinetics, and thereby carbonation efficiency, are also discussed. Then, we focus on the research progress of the most representative industrial solid wastes for CO₂ mineralization, process conditions, and their carbonation potential. Lastly, a market analysis of the precipitated carbonate products is provided to assess economic feasibility for practical applications. Full article

This study highlights the significant environmental and health risks associated with heavy metal contamination (As, Cd, Cr, and Pb) in Oreochromis niloticus (Nile tilapia) from two locations: the Khon Kaen municipal landfill (study site) and the Thapra commercial fish farm (reference site). It also evaluates potential human health risks and investigates genotoxicity and oxidative stress markers, including malondialdehyde, hydrogen peroxide (H₂O₂), catalase (CAT), and superoxide dismutase (SOD) in fish. Heavy metal concentrations were analyzed using inductively coupled plasma optical emission spectrometry. To determine genetic differentiation, inter-simple sequence repeats with dendrogram construction and genomic template stability (%GTS) were applied. The results showed that the average concentrations of As, Cd, Cr, and Pb in water samples were 0.0848, 0.536, 1.23, and 0.73 mg/L, respectively. These values exceeded safety limits, and the average Cd in sediment (1.162 mg/kg) was above regulatory thresholds. In fish muscle, the average metal concentrations (mg/kg) followed the order Cr (1.83) > Pb (0.69) > Cd (0.096) > As (0.0758), with Pb exceeding food quality standards. The bioaccumulation factor ranked as Cr > Pb > As > Cd. Health risk assessments, including health risk index and carcinogenic risk, suggested Pb contamination poses significant health risks through fish consumption. From dendrogram results, the %GTS of O. niloticus from the landfill and reference sites were 46.34 to 71.67% and 87.34 to 96.00%, respectively. This suggests that fish from the landfill site exhibited greater genetic diversity compared to those from the reference site. Specific oxidative stress markers revealed higher levels of H₂O₂ and significantly lower activities of CAT and SOD in landfill O. niloticus than in the reference site. These results emphasize the urgent need for environmental monitoring, stricter pollution controls, and improved waste management strategies to protect aquatic ecosystems and human health. Full article

Efficient cooling and heat recovery systems are becoming increasingly critical in large-scale commercial and industrial facilities, especially with the rising demand for sustainable energy solutions. Traditional air-conditioning and refrigeration systems often dissipate significant amounts of waste heat, which remains underutilized. This study addresses the challenge of harnessing low-potential waste heat from such systems to support fifth-generation district heating and cooling (5GDHC) networks, particularly in moderate-temperate regions like Flanders, Belgium. To evaluate the technical and economic feasibility of waste heat recovery, a methodology is developed that integrates established performance metrics—such as the energy efficiency ratio (EER), power usage effectiveness (PUE), and specific cooling demand (kW/t)—with capital (CapEx) and operational expenditure (OpEx) assessments. Empirical correlations, including regression analysis based on manufacturer data and operational case studies, are used to estimate equipment sizing and system performance across three operational modes. The study includes detailed modeling of data centers, cold storage facilities, and large supermarkets, taking into account climatic conditions, load factors, and thermal capacities. Results indicate that average cooling loads typically reach 58% of peak demand, with seasonal coefficient of performance (SCOP) values ranging from 6.1 to a maximum of 10.3. Waste heat recovery potential varies significantly across building types, with conversion rates from 33% to 68%, averaging at 59%. In data centers using water-to-water heat pumps, energy production reaches 10.1 GWh/year in heat pump mode and 8.6 GWh/year in heat exchanger mode. Despite variations in system complexity and building characteristics, OpEx and CapEx values converge closely (within 2.5%), demonstrating a well-balanced configuration. Simulations also confirm that large buildings operating above a 55% capacity factor provide the most favorable conditions for integrating waste heat into 5GDHC systems. In conclusion, the proposed approach enables the scalable and efficient integration of low-grade waste heat into district energy networks. While climatic and technical constraints exist, especially concerning temperature thresholds and equipment design, the results show strong potential for energy savings up to 40% in well-optimized systems. This highlights the viability of retrofitting large-scale cooling systems for dual-purpose operation, offering both environmental and economic benefits. Full article

As an aspect of green road construction, the use of waste plastic agricultural film in asphalt pavement not only mitigates environmental pollution but also enhances the mechanical properties of asphalt. However, it has been plagued by problems such as poor low-temperature crack resistance and poor compatibility. To address this problem, this study used waste low-density polyethylene (LDPE), sourced from waste film, and the plasticizer diisononyl phthalate (DINP) to enhance the properties of asphalt. Based on orthogonal tests, rheological property tests, conventional property tests, storage stability tests, fluorescence microscopy (FM), and Fourier transform infrared (FTIR) tests, waste LDPE/plasticizer DINP-modified asphalt samples were evaluated. Orthogonal tests indicated that a modified asphalt optimum preparation process of 30 min and 4500 rpm at 180 °C was beneficial. Conventional and rheological property tests revealed that 4% waste LDPE modified with 2.5% plasticizer DINP represents the optimal combination to effectively enhance the low-temperature rheological properties of asphalt while exerting minimal impact on its high-temperature characteristics. Storage stability and FM analysis indicated that waste LDPE is evenly dispersed in the modified asphalt binder when 3% plasticizer DINP is added. FTIR analysis revealed no change in the absorption peaks after waste LDPE and plasticizer DINP were added to asphalt, indicating that no chemical reactions occurred. Overall, waste LDPE/plasticizer DINP-modified asphalt exhibits excellent rheological properties and storage stability, which are conducive to green road construction and resource utilization. Full article