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30 pages, 1538 KiB  
Review
Circular Economy in the Construction Sector in Materials, Processes, and Case Studies: Research Review
by Alicja Krajewska and Monika Siewczyńska
Sustainability 2025, 17(15), 7029; https://doi.org/10.3390/su17157029 (registering DOI) - 2 Aug 2025
Abstract
Closed-loop processes can help reduce the environmental impact of the construction sector. Despite its growing popularity, the reuse of materials is still not a common practice. There are many studies available on material processing, design processes, and case studies, but the opportunities and [...] Read more.
Closed-loop processes can help reduce the environmental impact of the construction sector. Despite its growing popularity, the reuse of materials is still not a common practice. There are many studies available on material processing, design processes, and case studies, but the opportunities and challenges in this area have not been identified. Through a review of the scientific literature, including articles published in peer-reviewed journals, this study aims to organise the information collected in the form of an article and identify areas that require further research and expansion. When the articles are divided into the three groups mentioned above, the barriers and benefits of the research already carried out have been identified. The tools used in the research or processes were identified to highlight good practices that are worth replicating in the future. The challenges that commonly arose, the links between them, and their causes were also identified. Full article
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41 pages, 1651 KiB  
Review
Progress and Challenges in the Process of Using Solid Waste as a Catalyst for Biodiesel Synthesis
by Zhaolin Dong, Kaili Dong, Haotian Li, Liangyi Zhang and Yitong Wang
Molecules 2025, 30(15), 3243; https://doi.org/10.3390/molecules30153243 (registering DOI) - 1 Aug 2025
Abstract
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various [...] Read more.
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various methods for preparing biodiesel catalysts from solid waste. These methods not only enhance the utilization rate of waste but also reduce the production costs and environmental impact of biodiesel. Finally, the limitations of waste-based catalysts and future research directions are discussed. Research indicates that solid waste can serve as a catalyst carrier or active material for biodiesel production. Methods such as high-temperature calcination, impregnation, and coprecipitation facilitate structural modifications to the catalyst and the formation of active sites. The doping of metal ions not only alters the catalyst’s acid-base properties but also forms stable metal bonds with functional groups on the carrier, thereby maintaining catalyst stability. The application of microwave-assisted and ultrasound-assisted methods reduces reaction parameters, making biodiesel production more economical and sustainable. Overall, this study provides a scientific basis for the reuse of solid waste and ecological protection, emphasizes the development potential of waste-based catalysts in biodiesel production, and offers unique insights for innovation in this field, thereby accelerating the commercialization of biodiesel. Full article
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23 pages, 2231 KiB  
Review
Advanced Nuclear Reactors—Challenges Related to the Reprocessing of Spent Nuclear Fuel
by Katarzyna Kiegiel, Tomasz Smoliński and Irena Herdzik-Koniecko
Energies 2025, 18(15), 4080; https://doi.org/10.3390/en18154080 (registering DOI) - 1 Aug 2025
Abstract
Nuclear energy can help stop climate change by generating large amounts of emission-free electricity. Nuclear reactor designs are continually being developed to be more fuel efficient, safer, easier to construct, and to produce less nuclear waste. The term advanced nuclear reactors refers either [...] Read more.
Nuclear energy can help stop climate change by generating large amounts of emission-free electricity. Nuclear reactor designs are continually being developed to be more fuel efficient, safer, easier to construct, and to produce less nuclear waste. The term advanced nuclear reactors refers either to Generation III+ and Generation IV or small modular reactors. Every reactor is associated with the nuclear fuel cycle that must be economically viable and competitive. An important matter is optimization of fissile materials used in reactor and/or reprocessing of spent fuel and reuse. Currently operating reactors use the open cycle or partially closed cycle. Generation IV reactors are intended to play a significant role in reaching a fully closed cycle. At the same time, we can observe the growing interest in development of small modular reactors worldwide. SMRs can adopt either fuel cycle; they can be flexible depending on their design and fuel type. Spent nuclear fuel management should be an integral part of the development of new reactors. The proper management methods of the radioactive waste and spent fuel should be considered at an early stage of construction. The aim of this paper is to highlight the challenges related to reprocessing of new forms of nuclear fuel. Full article
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12 pages, 866 KiB  
Article
Reuse of Activated Carbon Filter Waste as Filler in Vulcanized Rubber Composites
by Viviane Chaves de Souza, Henrique Pina Cardim, Carlos Toshiyuki Hiranobe, Guilherme Pina Cardim, Iago William Zapelini, Leonardo Lataro Paim, Gleyson Tadeu Almeida Santos, Silvio Rainho Teixeira, Erivaldo Antônio da Silva, Renivaldo José dos Santos and Flávio Camargo Cabrera
J. Compos. Sci. 2025, 9(8), 406; https://doi.org/10.3390/jcs9080406 (registering DOI) - 1 Aug 2025
Abstract
The incorporation of residues into rubber composites has gained attention as a sustainable strategy to address waste management challenges while replacing commercial fillers. In this study, we investigated the potential use of water filter cartridge residue after exhaustion, composed of activated carbon, as [...] Read more.
The incorporation of residues into rubber composites has gained attention as a sustainable strategy to address waste management challenges while replacing commercial fillers. In this study, we investigated the potential use of water filter cartridge residue after exhaustion, composed of activated carbon, as a reinforcing filler in vulcanized natural rubber composites. Samples were prepared with 5, 10, 15, and 20 phr (per hundred rubber) of residue and compared to unfilled natural rubber. Stress vs. strain tests reached 13.9 MPa of tension at rupture for composites containing 10 phr of carbon-activated residues, representing a 21.9% increase compared to natural rubber. Interestingly, the tension at rupture for NR/AC10phr reached values close to those of NR/CB5phr (with carbon black N330) attaining 14.4 MPa. These results indicate that, even at relatively low concentrations, the carbon filter can offer partial substitution for commercial fillers. Moreover, the use of activated carbon from filter cartridges as filler in rubber composites provides an environmentally favorable alternative to energy-intensive regeneration processes for activated carbon. Full article
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19 pages, 1310 KiB  
Review
A Survey of Machine and Deep Learning Techniques in Analog Integrated Circuit Layout Synthesis
by Ricardo M. F. Martins
Microelectronics 2025, 1(1), 2; https://doi.org/10.3390/microelectronics1010002 (registering DOI) - 1 Aug 2025
Abstract
Automatic techniques for analog integrated circuit layout design have been proposed in the literature for over four decades. However, as analog design moves into deep nanometer integration nodes, the increasing number of design rules, the influence of layout-dependent effects, congestion, and the impact [...] Read more.
Automatic techniques for analog integrated circuit layout design have been proposed in the literature for over four decades. However, as analog design moves into deep nanometer integration nodes, the increasing number of design rules, the influence of layout-dependent effects, congestion, and the impact of parasitic structures constantly challenges existing automatic layout generation techniques and keeps the pressure on for further improvement. At the time of writing, no automatic tool or flow has been established in the industrial environment, resulting in a time-consuming and difficult-to-reuse design process. However, very recently, machine and deep learning techniques started to offer solutions for problems not dealt with in the previous generation of automatic layout tools and are reshaping analog design automation. Therefore, this paper conducts a review of the most recent analog integrated circuit automatic layout techniques powered by machine and deep learning methods, covering placement, routing, and trends on post-layout performance estimation, as well as providing an actual, complete, and comprehensive guide for circuit designers and design automation developers. Full article
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20 pages, 2027 KiB  
Article
Metal-Ion-Free Preparation of κ-Carrageenan/Cellulose Hydrogel Beads Using an Ionic Liquid Mixture for Effective Cationic Dye Removal
by Dojin Kim, Dong Han Kim, Jeong Eun Cha, Saerom Park and Sang Hyun Lee
Gels 2025, 11(8), 596; https://doi.org/10.3390/gels11080596 (registering DOI) - 1 Aug 2025
Abstract
A metal-ion-free method was developed to prepare κ-carrageenan/cellulose hydrogel beads for efficient cationic dye removal. The beads were fabricated using a mixture of 1-ethyl-3-methylimidazolium acetate and N,N-dimethylformamide as the solvent system, followed by aqueous ethanol-induced phase separation. This process eliminated the need for [...] Read more.
A metal-ion-free method was developed to prepare κ-carrageenan/cellulose hydrogel beads for efficient cationic dye removal. The beads were fabricated using a mixture of 1-ethyl-3-methylimidazolium acetate and N,N-dimethylformamide as the solvent system, followed by aqueous ethanol-induced phase separation. This process eliminated the need for metal-ion crosslinkers, which typically neutralize anionic sulfate groups in κ-carrageenan, thereby preserving a high density of accessible binding sites. The resulting beads formed robust interpenetrating polymer networks. The initial swelling ratio reached up to 28.3 g/g, and even after drying, the adsorption capacity remained over 50% of the original. The maximum adsorption capacity for crystal violet was 241 mg/g, increasing proportionally with κ-carrageenan content due to the higher surface concentration of anionic sulfate groups. Kinetic and isotherm analyses revealed pseudo-second-order and Langmuir-type monolayer adsorption, respectively, while thermodynamic parameters indicated that the process was spontaneous and exothermic. The beads retained structural integrity and adsorption performance across pH 3–9 and maintained over 90% of their capacity after five reuse cycles. These findings demonstrate that κ-carrageenan/cellulose hydrogel beads prepared via a metal-ion-free strategy offer a sustainable and effective platform for cationic dye removal from wastewater, with potential for heavy metal ion adsorption. Full article
(This article belongs to the Special Issue Physical and Mechanical Properties of Polymer Gels (3rd Edition))
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26 pages, 3459 KiB  
Article
Compressive Behaviour of Sustainable Concrete-Filled Steel Tubes Using Waste Glass and Rubber Glove Fibres
by Zobaer Saleheen, Tatheer Zahra, Renga Rao Krishnamoorthy and Sabrina Fawzia
Buildings 2025, 15(15), 2708; https://doi.org/10.3390/buildings15152708 (registering DOI) - 31 Jul 2025
Abstract
To reduce the carbon footprint of the concrete industry and promote a circular economy, this study explores the reuse of waste materials such as glass powder (GP) and nitrile rubber (NR) fibres in concrete. However, the inclusion of these waste materials results in [...] Read more.
To reduce the carbon footprint of the concrete industry and promote a circular economy, this study explores the reuse of waste materials such as glass powder (GP) and nitrile rubber (NR) fibres in concrete. However, the inclusion of these waste materials results in lower compressive strength compared to conventional concrete, limiting their application to non-structural elements. To overcome this limitation, this study adopts the concept of confined concrete by developing concrete-filled steel tube (CFST) stub columns. In total, twelve concrete mix variations were developed, with and without steel tube confinement. GP was utilised at replacement levels of 10–30% by weight of cement, while NR fibres were introduced at 0.5% and 1% by volume of concrete. The findings demonstrate that the incorporation of GP and NR fibres leads to a reduction in compressive strength, with a compounded effect observed when both materials are combined. Steel confinement within CFST columns effectively mitigated the strength reductions, restoring up to 17% of the lost capacity and significantly improving ductility and energy absorption capacity. All CFST columns exhibited consistent local outward buckling failure mode, irrespective of the concrete mix variations. A comparison with predictions from existing design codes and empirical models revealed discrepancies, underscoring the need for refined design approaches for CFST columns incorporating sustainable concrete infill. This study contributes valuable insights into the development of eco-friendly, high-performance structural systems, highlighting the potential of CFST technology in facilitating the adoption of waste materials in the construction sector. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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48 pages, 8533 KiB  
Systematic Review
Eco-Efficient Retrofitting of Rural Heritage: A Systematic Review of Sustainable Strategies
by Stefano Bigiotti, Mariangela Ludovica Santarsiero, Anna Irene Del Monaco and Alvaro Marucci
Energies 2025, 18(15), 4065; https://doi.org/10.3390/en18154065 (registering DOI) - 31 Jul 2025
Abstract
Through a systematic review of sustainable rural dwelling recovery, this study offers a broader reflection on retrofitting practices, viewing eco-efficiency as a means to enhance both cultural heritage and agricultural landscapes. The work is based on the assumption that vernacular architecture in rural [...] Read more.
Through a systematic review of sustainable rural dwelling recovery, this study offers a broader reflection on retrofitting practices, viewing eco-efficiency as a means to enhance both cultural heritage and agricultural landscapes. The work is based on the assumption that vernacular architecture in rural contexts embodies historical, cultural, and typological values worthy of preservation, while remaining adaptable to reuse through eco-efficient solutions and technological innovation. Using the PRISMA protocol, 115 scientific contributions were selected from 1711 initial records and classified into four macro-groups: landscape relationships; seismic and energy retrofitting; construction techniques and innovative materials; and morphological–typological analysis. Results show a predominance (over 50%) of passive design strategies, compatible materials, and low-impact techniques, while active systems are applied more selectively to protect cultural integrity. The study identifies replicable methodological models combining sustainability, cultural continuity, and functional adaptation, offering recommendations for future operational guidelines. Conscious eco-efficient retrofitting thus emerges as a strategic tool for the integrated valorization of rural landscapes and heritage. Full article
(This article belongs to the Special Issue Sustainable Building Energy and Environment: 2nd Edition)
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25 pages, 2349 KiB  
Article
Development of a Method for Determining Password Formation Rules Using Neural Networks
by Leila Rzayeva, Alissa Ryzhova, Merei Zhaparkhanova, Ali Myrzatay, Olzhas Konakbayev, Abilkair Imanberdi, Yussuf Ahmed and Zhaksylyk Kozhakhmet
Information 2025, 16(8), 655; https://doi.org/10.3390/info16080655 (registering DOI) - 31 Jul 2025
Abstract
According to the latest Verizon DBIR report, credential abuse, including password reuse and human factors in password creation, remains the leading attack vector. It was revealed that most users change their passwords only when they forget them, and 35% of respondents find mandatory [...] Read more.
According to the latest Verizon DBIR report, credential abuse, including password reuse and human factors in password creation, remains the leading attack vector. It was revealed that most users change their passwords only when they forget them, and 35% of respondents find mandatory password rotation policies inconvenient. These findings highlight the importance of combining technical solutions with user-focused education to strengthen password security. In this research, the “human factor in the creation of usernames and passwords” is considered a vulnerability, as identifying the patterns or rules used by users in password generation can significantly reduce the number of possible combinations that attackers need to try in order to gain access to personal data. The proposed method based on an LSTM model operates at a character level, detecting recurrent structures and generating generalized masks that reflect the most common components in password creation. Open datasets of 31,000 compromised passwords from real-world leaks were used to train the model and it achieved over 90% test accuracy without signs of overfitting. A new method of evaluating the individual password creation habits of users and automatically fetching context-rich keywords from a user’s public web and social media footprint via a keyword-extraction algorithm is developed, and this approach is incorporated into a web application that allows clients to locally fine-tune an LSTM model locally, run it through ONNX, and carry out all inference on-device, ensuring complete data confidentiality and adherence to privacy regulations. Full article
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41 pages, 580 KiB  
Review
The Alarming Effects of Per- and Polyfluoroalkyl Substances (PFAS) on One Health and Interconnections with Food-Producing Animals in Circular and Sustainable Agri-Food Systems
by Gerald C. Shurson
Sustainability 2025, 17(15), 6957; https://doi.org/10.3390/su17156957 (registering DOI) - 31 Jul 2025
Viewed by 45
Abstract
Per- and polyfluoroalkyl substances (PFAS) are synthetically produced chemicals that are causing a major One Health crisis. These “forever chemicals” are widely distributed globally in air, water, and soil, and because they are highly mobile and extremely difficult to degrade in the environment. [...] Read more.
Per- and polyfluoroalkyl substances (PFAS) are synthetically produced chemicals that are causing a major One Health crisis. These “forever chemicals” are widely distributed globally in air, water, and soil, and because they are highly mobile and extremely difficult to degrade in the environment. They cause additional health concerns in a circular bioeconomy and food system that recycles and reuses by-products and numerous types of waste materials. Uptake of PFAS by plants and food-producing animals ultimately leads to the consumption of PFAS-contaminated food that is associated with numerous adverse health and developmental effects in humans. Contaminated meat, milk, and eggs are some of the main sources of human PFAS exposure. Although there is no safe level of PFAS exposure, maximum tolerable PFAS consumption guidelines have been established for some countries. However, there is no international PFAS monitoring system, and there are no standardized international guidelines and mechanisms to prevent the consumption of PFAS-contaminated foods. Urgent action is needed to stop PFAS production except for critical uses, implementing effective water-purification treatments, preventing spreading sewage sludge on land and pastures used to produce food, and requiring marketers and manufacturers to use packaging that is free of PFAS. Full article
36 pages, 6099 KiB  
Article
RestRho: A JSON-Based Domain-Specific Language for Designing and Developing RESTful APIs to Validate RhoArchitecture
by Enrique Chavarriaga, Luis Rojas, Francy D. Rodríguez, Kat Sorbello and Francisco Jurado
Future Internet 2025, 17(8), 346; https://doi.org/10.3390/fi17080346 (registering DOI) - 31 Jul 2025
Viewed by 41
Abstract
Domain-Specific Languages with JSON grammar (JSON-DSLs) are specialized programming languages tailored to specific problem domains, offering higher abstraction levels and simplifying software implementation through the JSON standard. RhoArchitecture is an approach for designing and executing JSON-DSLs, incorporating a modular programming model, a JSON-based [...] Read more.
Domain-Specific Languages with JSON grammar (JSON-DSLs) are specialized programming languages tailored to specific problem domains, offering higher abstraction levels and simplifying software implementation through the JSON standard. RhoArchitecture is an approach for designing and executing JSON-DSLs, incorporating a modular programming model, a JSON-based evaluation engine, and an integrated web development environment. This paper presents RestRho, a RESTful NodeJS server developed using two JSON-DSLs designed with RhoArchitecture: SQLRho and DBRestRho. These languages enable declarative specification of database operations and HTTP requests, respectively, supporting modularity, reuse, and template-based transformations. We validate the RestRho implementation through a dual approach. First, we apply software metrics to assess code quality, maintainability, and complexity. Second, we conduct an empirical study involving 39 final-year computer engineering students, who completed 18 structured tasks and provided feedback via questionnaires. The results demonstrate the tool’s usability, development efficiency, and potential for adoption in web application development. Full article
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11 pages, 741 KiB  
Article
Wastewater Reuse to Address Climate Change: Insight from Legionella Contamination During Wastewater Treatment
by Manuela Macrì, Marta Catozzo, Silvia Bonetta and Sara Bonetta
Water 2025, 17(15), 2275; https://doi.org/10.3390/w17152275 - 31 Jul 2025
Viewed by 52
Abstract
Climate change is significantly affecting water availability, emphasising the need for sustainable strategies such as wastewater reuse. While this represents a promising alternative resource, insufficiently treated wastewater may pose health risks, particularly through aerosol formation during irrigation, which can facilitate Legionella transmission. This [...] Read more.
Climate change is significantly affecting water availability, emphasising the need for sustainable strategies such as wastewater reuse. While this represents a promising alternative resource, insufficiently treated wastewater may pose health risks, particularly through aerosol formation during irrigation, which can facilitate Legionella transmission. This study aimed to evaluate the presence of Legionella across various stages in a wastewater treatment plant (WWTP) that reuses effluent for agricultural purposes. Samples from the influent, four treatment phases, and the final effluent were analysed using both culture-based methods and quantitative PCR (qPCR) for Legionella spp. and L. pneumophila. qPCR detected Legionella spp. in all samples and L. pneumophila in 66% of them. In contrast, the culture-based analysis showed much lower detection levels, with only one positive sample at the influent stage—likely due to microbial interference or growth inhibition. Although contamination decreased in the final effluent, Legionella was still detected in water designated for reuse (Legionella spp. in 100% and L. pneumophila in 17% of samples). No treatment stage appeared to promote Legionella proliferation, likely due to WWTP characteristics, in addition to wastewater temperature and COD. These findings underscore the importance of monitoring Legionella in reclaimed water and developing effective control strategies to ensure the safe reuse of treated wastewater in agriculture. Full article
(This article belongs to the Special Issue Legionella: A Key Organism in Water Management)
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26 pages, 4899 KiB  
Article
Material Perception in Virtual Environments: Impacts on Thermal Perception, Emotions, and Functionality in Industrial Renovation
by Long He, Minjia Wu, Yue Ma, Di Cui, Yongjiang Wu and Yang Wei
Buildings 2025, 15(15), 2698; https://doi.org/10.3390/buildings15152698 (registering DOI) - 31 Jul 2025
Viewed by 49
Abstract
Industrial building renovation is a sustainable strategy to preserve urban heritage while meeting modern needs. However, how interior material scenes affect users’ emotions, thermal perception, and functional preferences remains underexplored in adaptive reuse contexts. This study used virtual reality (VR) to examine four [...] Read more.
Industrial building renovation is a sustainable strategy to preserve urban heritage while meeting modern needs. However, how interior material scenes affect users’ emotions, thermal perception, and functional preferences remains underexplored in adaptive reuse contexts. This study used virtual reality (VR) to examine four common material scenes—wood, concrete, red brick, and white-painted surfaces—within industrial renovation settings. A total of 159 participants experienced four Lumion-rendered VR environments and rated them on thermal perception (visual warmth, thermal sensation, comfort), emotional response (arousal, pleasure, restoration), and functional preference. Data were analyzed using repeated measures ANOVA and Pearson correlation. Wood and red brick scenes were associated with warm visuals; wood scenes received the highest ratings for thermal comfort and pleasure, white-painted scenes for restoration and arousal, and concrete scenes, the lowest scores overall. Functional preferences varied by space: white-painted and concrete scenes were most preferred in study/work settings, wood in social spaces, wood and red brick in rest areas, and concrete in exhibition spaces. By isolating material variables in VR, this study offers a novel empirical approach and practical guidance for material selection in adaptive reuse to enhance user comfort, emotional well-being, and spatial functionality in industrial heritage renovations. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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15 pages, 1273 KiB  
Article
Fungal Pretreatment of Alperujo for Bioproduct Recovery and Detoxification: Comparison of Two White Rot Fungi
by Viviana Benavides, Gustavo Ciudad, Fernanda Pinto-Ibieta, Elisabet Aranda, Victor Ramos-Muñoz, Maria A. Rao and Antonio Serrano
Agronomy 2025, 15(8), 1851; https://doi.org/10.3390/agronomy15081851 - 31 Jul 2025
Viewed by 74
Abstract
Alperujo, a solid by-product from the two-phase olive oil extraction process, poses significant environmental challenges due to its high organic load, phytotoxicity, and phenolic content. At the same time, it represents a promising feedstock for recovering value-added compounds such as phenols and volatile [...] Read more.
Alperujo, a solid by-product from the two-phase olive oil extraction process, poses significant environmental challenges due to its high organic load, phytotoxicity, and phenolic content. At the same time, it represents a promising feedstock for recovering value-added compounds such as phenols and volatile fatty acids (VFAs). When used as a substrate for white rot fungi (WRF), it also produces ligninolytic enzymes. This study explores the use of two native WRF, Anthracophyllum discolor and Stereum hirsutum, for the biotransformation of alperujo under solid-state fermentation conditions, with and without supplementation of copper and manganese, two cofactors known to enhance fungal enzymatic activity. S. hirsutum stood out for its ability to release high concentrations of phenolic compounds (up to 6001 ± 236 mg gallic acid eq L−1) and VFAs (up to 1627 ± 325 mg L−1) into the aqueous extract, particularly with metal supplementation. In contrast, A. discolor was more effective in degrading phenolic compounds within the solid matrix, achieving a 41% reduction over a 30-day period. However, its ability to accumulate phenolics and VFAs in the extract was limited. Both WRF exhibited increased enzymatic activities (particularly Laccase and Manganese Peroxidase) with the addition of Cu-Mn, highlighting the potential of the aqueous extract as a natural source of biocatalysts. Phytotoxicity assays using Solanum lycopersicum seeds confirmed a partial detoxification of the treated alperujo. However, none of the fungi could entirely eliminate inhibitory effects on their own, suggesting the need for complementary stabilization steps before agricultural reuse. Overall, the results indicate that S. hirsutum, especially when combined with metal supplementation, is better suited for valorizing alperujo through the recovery of bioactive compounds. Meanwhile, A. discolor may be more suitable for detoxifying the solid phase strategies. These findings support the integration of fungal pretreatment into biorefinery schemes that valorize agroindustrial residues while mitigating environmental issues. Full article
(This article belongs to the Section Agricultural Biosystem and Biological Engineering)
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23 pages, 1627 KiB  
Article
A Comprehensive Ecotoxicological Evaluation of a Treated Olive Mill Wastewater and Obtained Sludge
by José N. Pinto, Andreia Pereira, Ana Rita R. Silva, Diogo N. Cardoso, Amid Mostafaie, Fábio Campos, Iryna Rehan, Olga Moreira, Ivã Guidini Lopes, Daniel Murta, Alexandra Afonso, Margarida Oliveira, Karina S. Silvério, Maria Teresa Santos, Fátima Carvalho, Adelaide Almeida and Susana Loureiro
Toxics 2025, 13(8), 648; https://doi.org/10.3390/toxics13080648 (registering DOI) - 30 Jul 2025
Viewed by 129
Abstract
Olive mill wastewaters (OMWWs) are an environmental problem in the Mediterranean region, and it is crucial to explore strategies for their treatment and repurposing. The chemical precipitation technique (CPT) has been presented as a cost-effective wastewater treatment solution that might be applied to [...] Read more.
Olive mill wastewaters (OMWWs) are an environmental problem in the Mediterranean region, and it is crucial to explore strategies for their treatment and repurposing. The chemical precipitation technique (CPT) has been presented as a cost-effective wastewater treatment solution that might be applied to OMWW. The CPT-resulting precipitant subproducts (sludge) may be reprocessed (e.g., agricultural fertilizer and/or soil amendment), while the treated wastewater may be repurposed or reused (e.g., irrigation, aquaponic, or industrial processes). This study aimed to evaluate the efficacy of CPT in treating wastewater from the olive oil industry from an ecotoxicological perspective. Additionally, to assess the safe use of the obtained sludge in CPT treatment, its effects on soil biota were assessed. For this, a set of ecotoxicological assays using freshwater (Raphidocelis subcapitata, Daphnia magna and Danio rerio), terrestrial invertebrates (Folsomia candida and Enchytraeus crypticus), and plants (Brassica oleracea and Lolium perenne) were used as model organisms. Results demonstrated that CPT reduced OMWW toxicity to freshwater organisms, offering a favorable outlook on CPT’s potential as a wastewater treatment method. Increasing application rates of sludge in soil reduced the shoot biomass and the hydric content of both plants compared to the control. Survival of F. candida and E. crypticus was not affected by sludge in soil at any tested application rate, yet sludge application negatively affected the reproduction of both species, even at relevant sludge application rates (2%) of sludge in soils. Overall, the applicability of this sludge obtained by the CPT treatment in soils should be carefully evaluated due to the observed adverse effects on soil biota. Although the results of CPT were promising in reducing the toxicity of OMWW for these aquatic species, some adjustments/improvements should be performed to improve this technique and use all the obtained resources (treated water and sludge) in a fully circular perspective. Full article
(This article belongs to the Special Issue Biomass Conversion and Organic Waste Utilization in Wastewater)
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