Search Results (1,071)

Food waste filtrate (FW) and landfill leachate (LL) are high-strength organic wastewaters with complex compositions that pose significant challenges for conventional biological treatment. Anaerobic co-digestion is considered an effective strategy to improve process stability and methane recovery through substrate complementarity. In this study, an internal circulation (IC) anaerobic reactor was used to evaluate the co-digestion performance of FW and LL at different volumetric mixing ratios (3:7, 5:5, and 7:3). Methane production, COD removal, pH, volatile fatty acids (VFA), alkalinity, extracellular polymeric substances (EPS), enzyme activities, sludge morphology, and sludge structural and spectroscopic characteristics were analyzed to evaluate process performance and explore stability-related responses under different mixing ratios. The results showed that the 5:5 mixing ratio achieved the best overall performance. Under this condition, methane content remained at 78.79–81.60%, the volumetric methane production rate reached 893.38–1080.43 L CH₄/(m³·d), and methane yield was 0.219–0.265 L CH₄/g COD. COD removal efficiency was maintained at 86.93–88.35%. Meanwhile, the reactor operated within a relatively stable window, with pH of 6.98–7.80, VFA of 485.6–521.6 mg/L, alkalinity of 2000–3100 mg CaCO₃/L, and a VFA/TA ratio of 0.167–0.261. Compared with the other ratios, the 5:5 condition was associated with higher EPS levels, more favorable enzyme activity patterns, and a more compact sludge structure. Overall, FW-LL co-digestion exhibited clear ratio dependence, and the 5:5 mixing ratio provided the best balance between methane production, organic matter removal, and process stability. These findings offer quantitative support for substrate-ratio optimization and stable operation of anaerobic treatment systems for high-strength organic wastewaters. Full article

Reducing and managing emissions of mine waters and the minerals dissolved in them, and above all, using these wastes as resources, is an important element of sustainable development in regions undergoing a gradual phase-out of fossil fuel extraction. This article examines selected aspects of mine water management and the mineral substances contained therein, using the Polish hard coal mining industry as a case study, providing valuable insights for both Poland and other mining regions reducing raw material extraction regarding the sustainability of social water demand, mining sector restructuring, and Sustainable Development Goals (SDGs). In Poland, underground hard coal mining remains a significant source of mine water and mineral salt emissions. Mine waters, discharged into the catchments of major rivers (approximately 200 million m³ per year) along with their dissolved mineral compounds (approximately 1.5 million Mg per year), have repeatedly contributed to serious environmental disruptions, e.g., the phenomena of so-called “fish kill”. This study analyzes both the scale of emissions and the economic utilization of mineralized mine waters discharged to the surface by underground hard coal mining in Poland. Key processes and potential causes for the observed increase in environmental burdens are discussed. Furthermore, the paper presents a current statistical assessment of the trends and scale of emission changes, which can serve as a basis for environmental management decision-making amidst the decarbonization of the economy. Utilizing potential water resources and mineral compounds from mine waters for internal use or within circular economy applications can reduce environmental pressure, support compliance with sustainable development policies, and mitigate long-term impacts on post-mining regions. Full article

Utilizing lignin from agricultural wastes as a partial replacement for asphalt binder used in pavement presents a sustainable option, as it is abundant in nature. The effects of the addition of lignin on the properties and performance of asphalt binder and asphalt mixes were studied. Lignin was produced from rice husks, using a hydrothermal carbonization (HTC) treatment process. The rice husk-derived lignin was then mixed with a PG 67-22 binder at 0%, 5% and 10% of the mass of the total binder. The HTC treatment of rice husks at 250 °C created a powdery substance with an increased acid-insoluble lignin content and a reduced cellulose and hemicellulose content. The addition of 10% lignin was found to produce an unstable modified binder due to phase separation between the lignin and binder, thus requiring continuous stirring before use. Asphalt mixes prepared with 5% lignin exhibited better moisture-induced damage resistance compared to the control mix. Also, an improved rutting resistance of asphalt mixes was observed with the use of a lignin-modified binder. Lignin from rice husks may constitute a sustainable partial substitute for a crude-oil-based binder. Full article

Coal-fired power plants can adversely affect aquatic ecosystems through wastewater discharge, waste landfills, and the atmospheric deposition of toxic substances released during coal combustion. These processes degrade the water quality of nearby surface and underground water bodies. The study presents the impact of the coal-fired power plant Contour Global Maritza East 3 on the ecological status of the Sokolitsa River, reflected by changes in the composition and structure of the sensitive phytobenthos and macrozoobenthos communities and supporting environmental variables, including water temperature, pH, dissolved oxygen, conductivity, nutrients, sulfates, calcium, and calcium carbonate hardness. Methods for monitoring and assessing the ecological status of surface water bodies compliant with European and national legislation were applied to the studied biological quality elements and key physicochemical variables. Historical monitoring data from a ten-year period, 2013–2022, together with data collected during the study in 2023 and 2024 were analyzed and evaluated. The results indicated a significant increase in most physicochemical variables downstream of the CFPP compared with the upstream site, including water temperature, conductivity, calcium carbonate hardness, calcium, sulfates and nitrogen (N) nutrients (ammonium N, nitrite N, nitrate N, total N). The ecological status of the river deteriorated, as indicated by the negatively affected aquatic habitats and the changes in the taxonomic richness and abundance of the studied organism groups. Full article

The minimisation of substances of concern in packaging is a key objective of the European Union’s Packaging and Packaging Waste Regulation (PPWR), complementing existing legislation governing the safety of food contact materials. Per- and polyfluoroalkyl substances (PFAS) present particular challenges due to their persistence, chemical diversity, and documented use in certain food contact materials. Article 5 of the PPWR requires packaging to be designed and manufactured to minimise such substances throughout the life cycle. This study develops a structured, material-based PFAS risk matrix to support compliance screening for food packaging under Article 5. The approach combines scientific evidence on PFAS occurrence, functional applications, and analytical detection with material classification systems used in recyclability assessments. Packaging materials are categorised by their likelihood of PFAS relevance, enabling proportionate prioritisation of efforts. Application of the matrix shows that fibre-based materials with grease- or water-resistant treatments exhibit higher relevance than glass, untreated paper, or polyethylene terephthalate (PET). The framework also clarifies the role of total fluorine (TF) and extractable organic fluorine (EOF) as supportive, material-specific indicators rather than standalone compliance metrics. By integrating PFAS considerations into design, sourcing, and portfolio management, the framework promotes proactive chemical risk governance aligned with circular economy objectives. Full article

Agro-industrial waste impacts populations worldwide. Food waste, in turn, is a major source of complex lipids, carbohydrates, and other substances. Therefore, it is crucial to convert food waste into products that reduce environmental problems. Enzymatic hydrolysis has advantages over chemical hydrolysis. Examples include the enzymatic hydrolysis of starch by α-amylase and the hydrolysis of inulin by inulinase, which occur under milder environmental and temperature conditions than acid hydrolysis of starch or inulin. Despite these milder temperature conditions, during substate hydrolysis, enzyme deactivation occurs under exposure to temperature. As temperature increases above $T_{opt}$ (which maximizes catalytic activity), enzyme deactivation becomes more pronounced, leading to a decrease in enzyme activity. Therefore, determining the rate constant of deactivation $k_d$, during biotransformation is an important aspect in understanding enzyme kinetics. Most experimental studies focus on changes in enzyme activity with time and temperature. However, enzyme deactivation also occurs during enzymatic reactions conducted at different temperatures, and this process is characterized by specific deactivation parameters. The study is to present the rate constants of deactivation $k_d$, for selected biotransformation processes. The selected biotransformation processes are hydrolysis of olive oil by lipase, hydrolysis of inulin by inulinase, and hydrolysis of starch by α-amylase. Given the widespread use of enzymes in industry, the information on enzyme deactivation presented in this study can be used by engineers involved in modeling and optimizing enzymatic processes. This knowledge is also essential for the effective and sustainable use of enzymes in industrial applications. It is important to emphasize that the deactivation parameters discussed in this study also carry significant economic, social, and environmental implications. Full article

Technological solutions might be of great importance for reducing food waste. In the scope of this article, gas sensor systems for assessing the edibility of food have been studied, which can help to avoid food losses by suggesting consumption before spoilage or by separating infected fruits from fresh ones. Several series of measurements with various foodstuffs were conducted to develop methods that enable the identification of possible use cases in which gas sensors could be used to assess food condition as well as methods to calibrate such sensor systems. This paper presents results for oranges as an important target for grocery stores. The fruit headspace was measured by gas sensors, reference data were acquired using human assessment (appearance, odor, edibility) and gas chromatography–mass spectrometry (GC-MS) analysis. Data evaluation shows correlations between the performance of individual sensors for a technical assessment of fruit condition with marker substances identified by GC-MS, e.g., limonene for damaged oranges. Models were derived that are, in general, able to quantify the edibility or to classify defects/mold, but limitations in the applicability/transferability, e.g., between orange varieties, were also identified. With the knowledge gained, important steps could be taken towards an application-oriented setup, and recommendations regarding the sensors used, food trained, and calibration methods applied are derived. Full article

Glycolysate and glycerolysate—organic substances recovered from the chemical recycling of polyurethane waste—were investigated as sustainable plasticizers for acrylonitrile-butadiene rubber composites filled with 30 phr of calcium lignosulfonate or kraft lignin. The study evaluated the impact of these recycled plasticizers (added at 10 and 15 phr) on the curing process, morphology, rheology, mechanical and dynamic mechanical performances. Rheological analysis confirmed that both plasticizers significantly reduced the complex viscosity of the rubber compounds, with the effect being most pronounced at the 15 phr loading. While the incorporation of glycolysate and glycerolysate slightly extended the optimum cure time and decelerated the curing process, the cross-link density remained consistently within the range of 3.5–4 × 10⁻⁴ mol·cm⁻³. Morphological studies revealed that the plasticizers facilitated better dispersion of both lignin types and improved interfacial adhesion. However, the mechanical response differed significantly depending on the filler type. A consistent increase in elongation at break was observed only for composites filled with kraft lignin, where values rose from 341% for the reference up to 571% for the sample with 15 phr of glycolysate. In contrast, the application of plasticizers to calcium lignosulfonate-filled composites led to an initial decrease in both tensile strength and elongation at break. Notably, kraft lignin-filled composites exhibited superior overall mechanical performance, with glycolysate effectively maintaining tensile strength levels comparable to the reference. While both recovered substances performed effectively as processing aids, they had a negligible effect on the glass transition temperature. The results demonstrated that these recovered polyurethane derivatives are highly effective, sustainable alternatives to conventional plasticizers, showing a clear synergistic effect particularly with kraft lignin. Full article

Compost-based biostimulants (CBB) have emerged as a promising tool in sustainable agriculture, offering an eco-friendly approach to improving soil health, crop productivity, and environmental resilience. Derived from the controlled biodegradation of organic waste, CBB contains a diverse array of beneficial microorganisms, humic substances, and bioactive compounds that act synergistically to stimulate plant growth and soil biological activity. Mechanistically, CBB enhances nutrient acquisition by increasing plant-available nitrogen and phosphate solubility, promoting root development through phytohormone synthesis, and improving stress tolerance by modulating plant defense pathways and antioxidant activity. Additionally, their application enhances soil structure, microbial diversity, and carbon sequestration, making them integral to climate-smart agriculture. Despite their growing relevance, several challenges impede the widespread adoption of CBB. Variability in compost quality, lack of standardized production protocols, limited field-scale validation, and inconsistent regulatory frameworks hinder reproducibility and commercialization. Addressing these gaps requires interdisciplinary research that integrates microbiology, biochemistry, agronomy, and data science to better understand how microbial metabolites interact and optimize formulation strategies. Future research should prioritize the standardization of composting methods, long-term multi-crop field evaluations, and integration with precision agriculture tools for real-time soil monitoring. Policy harmonization, quality assurance frameworks, and farmer education are also vital for ensuring safe and effective use of CBB. Full article

The foundry industry produces over 66 million tons of mixed casting waste sand, containing toxic and harmful substances such as phenols and aldehydes, every year, which has caused serious soil pollution, water source pollution, and large amounts of CO₂ emissions. Green resource recycling and utilization are urgently needed. The hot method circulating fluidized bed furnace is currently the mainstream technology for the regeneration of casting waste sand. However, traditional equipment has a series of key technical bottlenecks, such as VOC (volatile organic compound) emissions, low yield of fine sand, poor stability of phase change sand, and uneven fluidization, which directly limit the effectiveness, large-scale promotion, and application of waste sand regeneration. This study, based on a self-designed experimental prototype, constructed models with different hood densities and inlet air velocity parameters. A CFD-DEM coupled model, combined with two turbulence models, was used for numerical simulations and experimental validation, and the optimal combination of fluidization parameters was determined. The study confirmed that the k–ω SST model is more suitable for precise simulation of such gas–solid two-phase flows. The research revealed quantitative relationships between key parameters and sand particle fluidization states, addressing the core problem of uneven fluidization in conventional bubbling furnaces and providing important guidance for the optimized design of new thermal cycle bubbling furnaces. It has significant engineering value for promoting the efficient resource utilization of foundry waste sand and the green and sustainable development of the industry. Full article

Landfill leachate, a byproduct of municipal solid waste treatment, typically contains hazardous substances such as toxic metals (e.g., lead) and eutrophication agents (e.g., phosphate). This study addresses the pressing challenge of polishing complex wastewater, such as landfill leachate, through the development of a novel ternary layered double hydroxide (LDH). As CaFe-LDHs are known to have an affinity for anions, and CoFe-LDHs have shown an affinity for toxic metal cations, CoCaFe-LDH was proposed to integrate both functionalities. The LDH was anchored on activated biochar to synthetize the novel composite adsorbent CoCaFe-LAB. Key operational parameters (including initial pH, adsorbent dosage, contact time, initial adsorbate concentration, presence of coexisting ions, and regeneration capability) were systematically evaluated. Kinetic and equilibrium analyses revealed that Elovich and Sips models, respectively, best described the adsorption behavior of Pb²⁺ and PO₄³⁻, indicating a heterogeneous adsorption system. Maximum adsorption capacities in synthetic solutions reached 140.81 mg Pb²⁺ g⁻¹ and 25.19 mg PO₄³⁻ g⁻¹ at 45 °C. The CoCaFe-LAB composite proved highly effective, particularly for lead removal. In real effluent tests, the adsorbent achieved complete phosphate removal (100%) from electro-oxidized landfill leachate at a dosage of 2.0 g L⁻¹, confirming its practical applicability and efficiency. Full article

The persistence of per- and polyfluoroalkyl substances (PFASs) poses a significant challenge in solid waste management. This paper systematically reviews the distribution characteristics of PFASs in various solid waste streams, including industrial sludge, food packaging, textiles, and electronic waste. It also evaluates the removal efficiency of four thermal treatment technologies—incineration, pyrolysis, smoldering combustion, and hydrothermal liquefaction (HTL)—for PFASs in solid waste. Although incineration and smoldering combustion can achieve destruction and removal efficiencies exceeding 99.99%, the release of short-chain byproducts remains a critical bottleneck. Pyrolysis effectively decontaminates solid-phase products but carries the risk of phase transfer into pyrolysis oils. The efficiency of HTL is highly dependent on process parameters. PFAS degradation is a radical-mediated process initiated by the dissociation of functional groups. We emphasize that substrate surface properties and the presence of counterions play pivotal roles in modulating these reaction pathways. The introduction of water vapor (as a hydrogen-rich medium), alkaline additives, or specific catalysts is considered a promising strategy to inhibit the recombination of reactive byproducts and enhance mineralization rates. Full article

One of the major current societal challenges concerns the reuse of waste materials and valuable substances to mitigate the environmental impact of human activities, which has led to the increasing release of pollutants, from plastics to pharmaceuticals. In this study, we report a simple recycling strategy for surgical masks to obtain an activated carbon-like material, suitable for the solid-phase extraction (SPE) of Phthalic acid esters (PAEss) from plastic bottled water. The sorbent was produced by high-temperature calcination after sulfuric acid treatment to enhance the thermal stability of polypropylene. The sorbent was characterized by thermal analysis, Raman spectroscopy, FTIR and scanning electron microscopy. SPE was used to preconcentrate the analytes, and the main parameters affecting the extraction, such as pH, sorbent amount, organic modifier percentage, ionic strength and elution volume, were optimized. PAEs were determined by UHPLC-PDA under gradient elution. The developed method was linear in the range 0.25–1000 ng/mL, with LOQs between 0.25 and 0.10 ng/mL and LODs between 0.008 and 0.003 ng/mL. Recovery ranged from 95.9 to 104.7%, the precision expressed as RSD% was below 7.32, and the accuracy expressed as BIAS% ranged from −5.75 to 5.93. The proposed approach provides a simple and low-cost valorization route for PPE waste, while enabling reliable PAEs analysis in drinking water. Full article

The topic of improving the strength and performance properties of secondary polyamide materials as part of their functional modification is a very relevant area of expanding the possibilities of secondary use of plastic waste. The article aims to conduct a systematic study of the combined modification of polyamide waste agglomerate by six different types of carbon materials to improve their technological and strength properties. PA6 waste agglomerate from polyamide clothing items, tights, socks, and various carbon materials were studied: masterbatch for polyamides MW-PA CB10, brown coal humic substances, coke residue from pyrolysis, a mixture of plastic waste, and finely dispersed coal enrichment waste. A sustainable polymer composite based on a modified agglomerate of PA6 waste was obtained by extruding pre-prepared raw materials in a single-screw extruder. The structural and morphological analysis of the studied carbon materials showed that, within the framework of the combined modification of polyamide-6 waste agglomerate, they should perform different functions related to their distinct morphology and chemical composition. Thus, humic substances can act as functional modifiers and compatibilizers due to their nanodispersity and a wide range of active chemical groups. In contrast, coke residue from pyrolysis and coal enrichment waste will act as a functional filler to improve the complex strength properties of sustainable polymer composites. As part of a study on the effect of modifying polyamide-6 waste agglomerate by carbon materials on its complex technological characteristics, it was demonstrated that humic substances enhance sustainable polymer composite’s technological properties by increasing the melting temperature and melt flow index while reducing density. The increase in the functional effect of humic substances is due to the growth of a wide range of active chemical groups (hydroxyl, carboxyl, peptide). During the initial oxidation of brown coal, the coke residue from pyrolysis and coal enrichment waste served as a filler, increasing the sustainable polymer composite’s density and melt flow index. As part of the study of the effect of modification by carbon materials on the complex strength characteristics of polyamide-6 waste agglomerate, it was shown that all carbon materials studied, except for coke residue, improve the strength characteristics of polyamide-6 waste agglomerate. The optimal content of different types of humic substances is 0.5% wt., while the sustainable polymer composite’s impact strength and breaking stress during bending increase with the increase in the functionalization of humic substances during the oxidation of brown coal. It has been shown that the combination of small amounts of oxidized humic substances at the level of 0.5% by weight, as a functional additive with a masterbatch MW-PACB10 in an amount of 2–3.5%wt., provides materials with increased impact strength from 23 to ~48 kJ/m² and bending fracture stress from 115 to ~135 MPa, which allows returning secondary PA6 waste to the “traditional areas of primary PA6” in the manufacture of general technical parts and products. Full article

Green Analytical Chemistry (GAC) provides a framework for reducing hazardous reagents, energy consumption, and waste. The topic has gained momentum across many chemical industries over the past 25 years; however, progress in implementing sustainable methods and conducting greenness assessments within forensic laboratories has been comparatively slow. The purpose of this review is to highlight green approaches to analytical separation methods, including greenness assessment metrics, that have been reported in the literature for forensic chemistry and toxicology applications and to raise awareness of GAC in the forensic field. Recent scientific literature highlights promising advances in greener sample preparation and chromatographic approaches, particularly in forensic toxicology and seized-drug analysis. Emerging trends include the use of green solvents, bio-based and deep eutectic solvent systems, and the rapid expansion of microextraction techniques such as SPME, LPME, MEPS, FPSE, and DLLME, which reduce solvent volumes, minimize waste, and support higher-throughput workflows. Parallel developments in portable and miniaturized chromatographic instrumentation such as miniaturized LC–MS systems with increased detection specificity and Lab-on-a-Chip applications show promise for in situ measurements in the field. Ambient ionization mass spectrometry—in particular, DESI and DART—has had a major impact on forensic chemistry by providing tools for the rapid and direct analysis of chemical compounds in complex matrices with little or no sample preparation. Greenness assessment tools—including AGREE, AGREEprep, Eco-Scale, GAPI, and BAGI—are increasingly applied to evaluate analytical methods in forensic chemistry and toxicology, including those used for novel psychoactive substances. Although many green methodologies are well documented, their routine implementation remains limited. The continued integration of green solvents, microextractions, portable instrumentation, and standardized greenness metrics will be essential for advancing sustainable forensic separations. Full article