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Search Results (229)

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Keywords = beneficial reuse

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18 pages, 7363 KiB  
Article
Agronomic Evaluation of Compost Formulations Based on Mining Tailings and Microbial Mats from Geothermal Sources
by María Jesús Puy-Alquiza, Miren Yosune Miranda Puy, Raúl Miranda-Avilés, Pooja Vinod Kshirsagar and Cristina Daniela Moncada Sanchez
Recycling 2025, 10(4), 156; https://doi.org/10.3390/recycling10040156 - 5 Aug 2025
Abstract
This study, conducted in Mexico, evaluates the agricultural potential of three compost formulations BFS1, BFS2, and BFS3 produced from mining tailings and thermophilic microbial mats and collected from geothermal environments. The physicochemical characterization included pH, electrical conductivity (EC), macronutrients (N, P, K, Ca, [...] Read more.
This study, conducted in Mexico, evaluates the agricultural potential of three compost formulations BFS1, BFS2, and BFS3 produced from mining tailings and thermophilic microbial mats and collected from geothermal environments. The physicochemical characterization included pH, electrical conductivity (EC), macronutrients (N, P, K, Ca, Mg, and S), micronutrients (Fe, Zn, B, Cu, Mn, Mo, and Ni), organic matter (OM), and the carbon-to-nitrogen (C/N) ratio. All composts exhibited neutral pH values (7.38–7.52), high OM content (38.5–48.4%), and optimal C/N ratios (10.5–13.9), indicating maturity and chemical stability. Nitrogen ranged from 19 to 21 kg·t−1, while potassium and calcium were present in concentrations beneficial for crop development. However, EC values (3.43–3.66 dS/m) and boron levels (>160 ppm) were moderately high, requiring caution in saline soils or with boron-sensitive crops. A semi-quantitative Compost Quality Index (CQI) ranked BFS3 highest due to elevated OM and potassium content, followed by BFS1. BFS2, while rich in nitrogen, scored lower due to excessive boron. One-way ANOVA revealed no significant difference in nitrogen (p > 0.05), but it did reveal significant differences in potassium (p < 0.01) and boron (p < 0.001) among formulations. These results confirm the potential of mining tailings—microbial mat composts are low-cost, nutrient-rich biofertilizers. They are suitable for field crops or as components in nursery substrates, particularly when EC and boron are managed through dilution. This study promotes the circular reuse of geothermal and industrial residues and contributes to sustainable soil restoration practices in mining-affected regions through innovative composting strategies. Full article
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5 pages, 270 KiB  
Proceeding Paper
Building a Circular Economy Option Through Wastewater Treatment and a Resource Recovery Approach
by Anastasios Zouboulis and Effrosyni Peleka
Proceedings 2025, 121(1), 10; https://doi.org/10.3390/proceedings2025121010 - 24 Jul 2025
Viewed by 193
Abstract
This work studies and analyzes the transition from a linear to a circular economy through wastewater treatment and resource recovery. As wastewater volumes grow, sustainable management becomes critical. This study highlights the reuse of treated effluent, beneficial sludge utilization, and energy generation via [...] Read more.
This work studies and analyzes the transition from a linear to a circular economy through wastewater treatment and resource recovery. As wastewater volumes grow, sustainable management becomes critical. This study highlights the reuse of treated effluent, beneficial sludge utilization, and energy generation via anaerobic digestion. Wastewater treatment plants should be envisioned as hubs for recovering water, materials, and energy, rather than disposal facilities. Emphasizing resource efficiency, the circular economy approach offers viable solutions to challenges related to resource scarcity, climate change, and ecological impact. Full article
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18 pages, 2154 KiB  
Article
Performance Limits of Hydraulic-Binder Stabilization for Dredged Sediments: Comparative Case Studies
by Abdeljalil Zri, Nor-Edine Abriak, Amine el Mahdi Safhi, Shima Pilehvar and Mahdi Kioumarsi
Buildings 2025, 15(14), 2484; https://doi.org/10.3390/buildings15142484 - 15 Jul 2025
Viewed by 386
Abstract
Maintenance dredging produces large volumes of fine sediments that are commonly discarded, despite increasing pressure for beneficial reuse. Lime–cement stabilization offers one pathway, yet field performance is highly variable. This study juxtaposes two French marine dredged sediments—DS-F (low plasticity, organic matter (OM) ≈ [...] Read more.
Maintenance dredging produces large volumes of fine sediments that are commonly discarded, despite increasing pressure for beneficial reuse. Lime–cement stabilization offers one pathway, yet field performance is highly variable. This study juxtaposes two French marine dredged sediments—DS-F (low plasticity, organic matter (OM) ≈ 2 wt.%) and DS-M (high plasticity, OM ≈ 18 wt.%)—treated with practical hydraulic road binder (HRB) dosages. This is the first French study that directly contrasts two different DS types under identical HRB treatment and proposes practical boundary thresholds. Physical indexes (particle size, methylene-blue value, Atterberg limits, OM) were measured; mixtures were compacted (Modified Proctor) and tested for immediate bearing index (IBI). IBI, unconfined compressive strength, indirect tensile strength, and elastic modulus were determined. DS-F reached IBI ≈ 90–125%, UCS ≈ 4.7–5.9 MPa, and ITS ≈ 0.40–0.47 MPa with only 6–8 wt.% HRB, satisfying LCPC-SETRA class S2–S3 requirements for road subgrades. DS-M never exceeded IBI ≈ 8%, despite 3 wt.% lime + 6 wt.% cement. A decision matrix distilled from these cases and recent literature shows that successful stabilization requires MBV < 3 g/100 g, plastic index < 25%, OM < 7 wt.%, and fine particles < 35%. These thresholds permit rapid screening of dredged lots before costly treatment. Highlighting both positive and negative evidence clarifies the realistic performance envelope of soil–cement reuse and supports circular-economy management of DS. Full article
(This article belongs to the Collection Advanced Concrete Materials in Construction)
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20 pages, 2249 KiB  
Article
Cellulolytic Potential of Newly Isolated Alcohol-Tolerant Bacillus methylotrophicus
by Anna Choińska-Pulit, Justyna Sobolczyk-Bednarek and Wojciech Łaba
Materials 2025, 18(14), 3256; https://doi.org/10.3390/ma18143256 - 10 Jul 2025
Viewed by 278
Abstract
Reprocessing lignocellulosic waste to obtain new products for industrial purposes is a vital part of circular economy. This paper reports the cellulase production by newly isolated Bacillus methylotrophicus cultured on lignocellulosic agro-industrial by-products, out of which brewer’s spent grain (BSG) was selected as [...] Read more.
Reprocessing lignocellulosic waste to obtain new products for industrial purposes is a vital part of circular economy. This paper reports the cellulase production by newly isolated Bacillus methylotrophicus cultured on lignocellulosic agro-industrial by-products, out of which brewer’s spent grain (BSG) was selected as most beneficial. Plackett–Burman design was used for screening medium components, while Box–Behnken design was further applied to model the impact of the three most influential variables. The maximum approximated cellulase activity was 0.469 U/mL (1 U = 1 µmol of reducing sugars/1 min), at 48.6 g/L substrate, 5.3 g/L ammonium sulfate, pH 6.1. The partially purified cellulase was characterized, which demonstrated broad range of optimal pH (6.5–9.4), temperature (50–60 °C), and sensitivity to metals. Changes in lignin and pentosans content was demonstrated as a result of BSG hydrolysis with a cell-free cellulase preparation. The produced enzyme was used for hydrolysis of various chemically pretreated (NaOH and H2SO4) cellulosic substrates, where for reused alkali-pretreated BSG (after microbial enzyme production) the saccharification efficiency was at a level of 25%. The cellulolytic potential of the bacterial strain, along with its resistance to ethanol, present a beneficial combination, potentially applicable to aid saccharification of lignocellulosic by-products for biofuel production. Full article
(This article belongs to the Special Issue Biomass Materials Recycling: Utilization and Valorisation)
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19 pages, 914 KiB  
Review
The Incorporation of Adsorbents with Contrasting Properties into the Soil Substrate for the Removal of Multiple Pollutants in Stormwater Treatment for the Reuse of Water—A Review
by Paripurnanda Loganathan, Jaya Kandasamy, Harsha Ratnaweera and Saravanamuthu Vigneswaran
Water 2025, 17(13), 2007; https://doi.org/10.3390/w17132007 - 3 Jul 2025
Viewed by 399
Abstract
Stormwater carries significant amounts of pollutants—including metals, microorganisms, organic micropollutants, and nutrients—from land surfaces into nearby water bodies, leading to water quality deterioration and threats to both human health and ecosystems. The removal of these contaminants is essential not only for environmental protection, [...] Read more.
Stormwater carries significant amounts of pollutants—including metals, microorganisms, organic micropollutants, and nutrients—from land surfaces into nearby water bodies, leading to water quality deterioration and threats to both human health and ecosystems. The removal of these contaminants is essential not only for environmental protection, but also to enable the reuse of treated water for various beneficial applications. Common treatment methods include bioretention systems, biofiltration, constructed wetlands, rain gardens, swales, and permeable pavements. To improve pollutant removal efficiency, adsorbent materials are often incorporated into the soil substrate of these treatment devices. However, most research on adsorbents has focused on their effectiveness against one or two specific pollutants and has been conducted under static, short-term laboratory conditions rather than dynamic, field-relevant scenarios. Column-based dynamic filtration type studies, which are more informative for field applications, are limited. In one study, a combination of two or more adsorbents with contrasting properties that matched the affinity preferences of the different pollutants to the substrate media removed 77–100% of several heavy metals that occur in real stormwater compared to 38–73% removal with only one adsorbent. In another study, polycyclic aromatic hydrocarbon removal with zeolite was only 30–50%, but increased to >99% with 0.3% granular activated carbon addition. Long-term dynamic column-based filtration experiments and field studies using real stormwater, which contains a wide range of pollutants, are recommended to better evaluate the performances of the combined adsorbent systems. Full article
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17 pages, 9104 KiB  
Article
Analysis and Chromium Recovery from Ferrochrome Waste (Stockpiled Refined Ferrochrome Slags)
by Otegen Sariyev, Lyazat Tolymbekova, Murat Dossekenov, Bauyrzhan Kelamanov, Dauren Yessengaliyev, Assel Davletova and Assylbek Abdirashit
Metals 2025, 15(7), 740; https://doi.org/10.3390/met15070740 - 30 Jun 2025
Viewed by 233
Abstract
This study investigates the effectiveness of various beneficiation methods for recovering chromium from refined ferrochrome slag. Dry magnetic separation at different field intensities (0.45 T and 0.8 T) showed that selective extraction of metallic chromium (Crmet) is more efficient at 0.45 [...] Read more.
This study investigates the effectiveness of various beneficiation methods for recovering chromium from refined ferrochrome slag. Dry magnetic separation at different field intensities (0.45 T and 0.8 T) showed that selective extraction of metallic chromium (Crmet) is more efficient at 0.45 T, achieving a recovery rate of up to 90.05%. Pneumatic separation using SEPAIR technology demonstrated promising results, especially for wide particle size fractions (0–20 mm), where chromium recovery reached 40.32% due to density differences between slag particles and metallic inclusions. Enrichment on a shaking table proved to be the most selective method, producing a concentrate with 29.9% Cr and 90.7% recovery, although the yield was low (3.8%). SEM-EDX and SEM-BSE analyses confirmed the heterogeneous phase composition of slag grains, revealing chromium–iron alloys embedded in oxide matrices. Based on laboratory experiments and material characterization, it is concluded that magnetic separation can be used for preliminary concentration, pneumatic classification is effective for processing bulk slag with economic potential, and gravity concentration on shaking tables is suitable for producing high-grade concentrates. The resulting tailings, low in chromium, are suitable for reuse in the production of building materials after carbonation treatment. Full article
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26 pages, 2941 KiB  
Article
A Fungi-Driven Sustainable Circular Model Restores Saline Coastal Soils and Boosts Farm Returns
by Fei Bian, Yonghui Wang, Haixia Ren, Luzhang Wan, Huidong Guo, Yuxue Jia, Xia Liu, Fanhua Ning, Guojun Shi and Pengfei Ren
Horticulturae 2025, 11(7), 730; https://doi.org/10.3390/horticulturae11070730 - 23 Jun 2025
Viewed by 435
Abstract
Agricultural production in the saline–alkaline soils of the Yellow River Delta faces persistent challenges in waste recycling and soil improvement. We developed a three-stage circular agriculture model integrating “crop straw–edible mushrooms–vegetables,” enabling simultaneous waste utilization and soil remediation within one year (two mushroom [...] Read more.
Agricultural production in the saline–alkaline soils of the Yellow River Delta faces persistent challenges in waste recycling and soil improvement. We developed a three-stage circular agriculture model integrating “crop straw–edible mushrooms–vegetables,” enabling simultaneous waste utilization and soil remediation within one year (two mushroom and two vegetable cycles annually). Crop straw was first used to cultivate Pleurotus eryngii, achieving 80% biological efficiency and reducing substrate costs by ~36.3%. The spent mushroom substrate (SMS) was then reused for Ganoderma lucidum and vegetable cultivation, maximizing the resource efficiency. SMS application significantly improved soil properties: organic matter increased 11-fold (from 14.8 to 162.78 g/kg) and pH decreased from 8.34 to ~6.75. The available phosphorus and potassium contents increased several-fold compared to untreated soil. Metagenomic analysis showed the enrichment of beneficial decomposer bacteria (Hyphomicrobiales, Burkholderiales, and Streptomyces) and functional genes involved in glyoxylate metabolism, nitrogen cycling, and lignocellulose degradation. These changes shifted the microbial community from a stress-tolerant to a nutrient-cycling profile. The vegetable yield and quality improved markedly: cabbage and cauliflower yields increased by 34–38%, and the tomato lycopene content rose by 179%. Economically, the system generated 1,695,000–1,962,881.4 CNY per hectare annually and reduced fertilizer costs by ~450,000 CNY per hectare. This mushroom–vegetable rotation addresses ecological bottlenecks in saline–alkaline lands through lignin-driven carbon release, organic acid-mediated pH reduction, and actinomycete-dominated decomposition, offering a sustainable agricultural strategy for coastal regions. Full article
(This article belongs to the Special Issue Advances in Propagation and Cultivation of Mushroom)
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18 pages, 733 KiB  
Review
Dredge Sediment as an Opportunity: A Comprehensive and Updated Review of Beneficial Uses in Marine, River, and Lagoon Eco-Systems
by Chiara Fratini, Serena Anselmi and Monia Renzi
Environments 2025, 12(6), 200; https://doi.org/10.3390/environments12060200 - 12 Jun 2025
Viewed by 1193
Abstract
Dredging is essential for the maintenance of ports, waterways, lakes, and lagoons to ensure their operability and economic value. Over the last few decades, scientists have focused on the significant environmental challenges associated with dredging, including habitat destruction, loss of biodiversity, sediment suspension, [...] Read more.
Dredging is essential for the maintenance of ports, waterways, lakes, and lagoons to ensure their operability and economic value. Over the last few decades, scientists have focused on the significant environmental challenges associated with dredging, including habitat destruction, loss of biodiversity, sediment suspension, and contamination with heavy metals and organic pollutants. The huge loss of sediment in coastal areas and the associated erosion processes are now forcing stakeholders to look ahead and turn potential problems into an opportunity to develop new sediment management strategies, beyond environmental protection, toward ecosystem restoration and coastal resilience. Moreover, the European and Italian strategies, such as the European Green Deal (EGD) and the Italian Ecological Transition Plan (PTE), highlight the need to reuse dredge sediment in circular economy strategies, transforming them into valuable resources for construction, agriculture, and environmental restoration projects. European legislation on dredging is fundamental to the issue of management and priorities of dredged materials, but the implementation rules are deferred to individual member states. In Italy, the Ministerial Decree 173/2016 covers the main aspects of dredge activities and dredge sediment management. Moreover, it encourages the remediation and reuse of the dredge sediment. This study starts with a comprehensive analysis of the innovative remediation techniques that minimize impacts and promote sustainable, beneficial sediment management. Different remediation methods, such as electrochemical treatments, chemical stabilization, emerging nanotechnologies, bioremediation, and phytoremediation, will be evaluated for their effectiveness in reducing pollution. Finally, we highlight new perspectives, integrated strategies, and multidisciplinary approaches that combine various technological innovations, including artificial intelligence, to enhance sediment reuse with the aim of promoting economic growth and environmental protection. Full article
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19 pages, 1224 KiB  
Review
Environmental Impact of Wastewater on Surface and Groundwater in Central Asia
by Marzhan S. Kalmakhanova, Assel A. Kurtebayeva, Zhanna T. Tleuova, Bagdat Satybaldiev, Seitzhan A. Orynbayev, Arindam Malakar, Helder T. Gomes and Daniel D. Snow
Sustainability 2025, 17(12), 5370; https://doi.org/10.3390/su17125370 - 11 Jun 2025
Viewed by 675
Abstract
This review aims to increase attention on present water quality issues on Central Asia, finding gaps in the literature on ways to address treatment needs, and help ensure future use of Central Asia surface waters and groundwater for all beneficial uses. Central Asia [...] Read more.
This review aims to increase attention on present water quality issues on Central Asia, finding gaps in the literature on ways to address treatment needs, and help ensure future use of Central Asia surface waters and groundwater for all beneficial uses. Central Asia is a landlocked region known for its harsh climatic conditions and scarce water resources, despite being home to some of the world’s largest internal drainage basins. The available literature suggests that increasing salinity has rendered water unsuitable for irrigation and consumption; hazardous trace elements are found throughout Central Asia, most often associated with mining and industrial sources; and that legacy pesticides influence water quality, particularly in agriculturally influenced basins. This study also focuses on the effects of municipal and industrial wastewater discharge. Additionally, the impact of inadequately treated wastewater on water resources is analyzed through a review of available data and reports regarding surface and groundwater quantity and quality. Given the challenges of water scarcity and accessibility, the reuse of treated wastewater is becoming increasingly important, offering a valuable alternative that necessitates careful oversight to ensure public health, environmental sustainability, and water security. However, due to insufficient financial and technical resources, along with underdeveloped regulatory frameworks, many urban areas lack adequate wastewater treatment facilities, significantly constraining their safe and sustainable reuse. Proper management of wastewater effluent is critical, as it directly influences the quality of both surface and groundwater, which serve as key sources for drinking water and irrigation. Due to their persistent and biologically active nature even at trace levels, we discuss contaminants of emerging concern such as antibiotics, pharmaceuticals, and modern agrochemicals. This review thus highlights gaps in the literature reporting on impacts of wastewater inputs to water quality in Central Asia. It is recommended that future research and efforts should focus on exploring sustainable solutions for water quality management and pollution control to assure environmental sustainability and public health. Full article
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19 pages, 11793 KiB  
Article
Investigating the Recovery of PVDF/TiO2 Photocatalyst for Methylene Blue Degradation
by Vi N. D. Nguyen, Hoang-Jyh Leu, Huy N. Q. Phan, Tan-Trung Nguyen and Dat H. M. Ngo
Processes 2025, 13(5), 1392; https://doi.org/10.3390/pr13051392 - 2 May 2025
Viewed by 737
Abstract
The increasing environmental concerns over and demand for sustainable solutions have driven research into the efficient recovery and reuse of waste materials, particularly from photocatalysts used in wastewater treatment. This study addresses the critical challenge posed by used PVDF/TiO2 photocatalysts, which, if [...] Read more.
The increasing environmental concerns over and demand for sustainable solutions have driven research into the efficient recovery and reuse of waste materials, particularly from photocatalysts used in wastewater treatment. This study addresses the critical challenge posed by used PVDF/TiO2 photocatalysts, which, if not properly managed, contribute to environmental pollution. A practical recovery technique based on the phase inversion method was developed to separate and purify PVDF, TiO2, and the solvent NMP from used composite materials. This method led to recovery rates of 95.17% for PVDF, 98.35% for NMP, and 67% for TiO2. The recycled photocatalyst was then reassembled and tested for its ability to degrade methylene blue, a common dye pollutant. A Box–Behnken design was employed to optimize the treatment conditions, ensuring the process was both efficient and reproducible. The regenerated material achieved up to 99.6% efficiency in the first cycle, with a slight reduction in efficiency observed across subsequent cycles, maintaining over 92% efficiency after 10 cycles. These findings confirm that effective recovery of photocatalytic materials is not only feasible but also beneficial in reducing waste and maintaining high treatment performance. Full article
(This article belongs to the Section Chemical Processes and Systems)
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20 pages, 2995 KiB  
Article
Environmental Life Cycle Assessment of Class A Biosolids Production Using Conventional and Low-Cost, Low-Tech Processes at Small Water Resource Recovery Facilities
by Janna L. Brown, Robert M. Handler, Jennifer G. Becker and Eric A. Seagren
Appl. Sci. 2025, 15(7), 3482; https://doi.org/10.3390/app15073482 - 22 Mar 2025
Viewed by 615
Abstract
Producing Class A biosolids that can be distributed or land-applied without restriction is a beneficial way to reuse wastewater treatment solids. For small water resource recovery facilities (WRRFs) in particular, low-cost, low-tech (LCLT) processes may be an appealing alternative to conventional technologies for [...] Read more.
Producing Class A biosolids that can be distributed or land-applied without restriction is a beneficial way to reuse wastewater treatment solids. For small water resource recovery facilities (WRRFs) in particular, low-cost, low-tech (LCLT) processes may be an appealing alternative to conventional technologies for producing Class A biosolids, such as processes to further reduce pathogens (PFRPs). Conventional Class A biosolids treatment processes tend to be energy-intensive and involve complex equipment and operations. However, a systematic comparison of the overall sustainability of conventional processes and LCLT alternatives for producing Class A biosolids to aid decision makers in selecting treatment processes is not readily available. Therefore, this study used life cycle assessments to compare five Class A biosolids treatment processes, including three conventional processes—Composting, Direct Heat Drying, and temperature-phased anaerobic digestion (TPAD)—and two LCLT processes—Air Drying, and long-term Lagoon Storage followed by Air Drying—on the basis of their environmental impacts. The environmental impacts were normalized to facilitate a comparison of the processes. The results indicate that Composting and Direct Heat Drying had the most significant environmental impacts, primarily from the biogenic emissions during Composting and the natural gas requirements for Direct Heat Drying. In comparison, TPAD and Air Drying had the lowest environmental impacts, and Lagoon Storage had intermediate impacts. Thus, LCLT processes may be more sustainable than some, but not all, conventional PFRPs. Full article
(This article belongs to the Special Issue New Approaches to Water Treatment: Challenges and Trends)
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42 pages, 4134 KiB  
Review
Solvent-Based Recycling as a Waste Management Strategy for Fibre-Reinforced Polymers: Current State of the Art
by Matthew J. Keith, Bushra Al-Duri, Tom O. McDonald and Gary A. Leeke
Polymers 2025, 17(7), 843; https://doi.org/10.3390/polym17070843 - 21 Mar 2025
Viewed by 1416
Abstract
The growing use of fibre-reinforced polymers (FRPs) is driving a demand for the development of sustainable end-of-life strategies. Solvolysis, a chemical recycling method using solvents to decompose the polymer matrix, has emerged as a promising approach for reclaiming both fibres and organic compounds [...] Read more.
The growing use of fibre-reinforced polymers (FRPs) is driving a demand for the development of sustainable end-of-life strategies. Solvolysis, a chemical recycling method using solvents to decompose the polymer matrix, has emerged as a promising approach for reclaiming both fibres and organic compounds from FRP waste. This work provides a comprehensive overview of solvolysis techniques by discussing the environmental benefits and economic opportunities of this technology, summarising the process conditions, and evaluating the characteristics of the recovered products. The economic viability of solvolysis lies in recovering high-value components; predominantly carbon fibres from CFRPs and organic products from GFRPs, which are suitable for reuse or as a feedstock for new composites. Solvolysis can operate under low temperature and pressure (LTP) or high temperature and pressure (HTP) conditions. The choice of solvent, catalyst, reaction time, and temperature is crucial to achieving high resin decomposition while preserving fibre properties. To achieve an economically viable and environmentally beneficial process, it will be essential to optimise these parameters. A key challenge is maintaining the strength and surface properties of the recovered fibres, as degradation in their performance can limit their suitability for high-performance applications. The implication of this is that, without careful consideration of the recycling process, FRPs cannot be fully circular. They will be continuously downgraded into low-value applications and ultimately incinerated or landfilled. This review further explores the diversity of organic products obtained, which can range from monomers to oligomers to complex mixtures. Efficient separation and upgrading techniques, such as distillation and liquid–liquid extraction, are essential to maximise the value of the recovered organics. These additional processing steps are likely to result in greater financial and resource costs within a commercial recycling system. This review concludes with a summary of commercial solvent-based recycling ventures and an outlook on future research directions, which includes the need to develop processes capable of recovering high-value, long carbon fibres. Successful development of such a process would represent a step-change in the value proposition of a carbon fibre recycling industry. Full article
(This article belongs to the Special Issue New Polymer Fibers: Production and Applications)
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21 pages, 2279 KiB  
Article
Chlorination of Antivirals in Wastewater: Effects of Microplastics and Ecotoxicity on Aquatic and Terrestrial Species
by Nilay Bilgin-Saritas, Emel Topuz and Elif Pehlivanoglu
Processes 2025, 13(3), 866; https://doi.org/10.3390/pr13030866 - 15 Mar 2025
Viewed by 692
Abstract
The presence of pharmaceuticals in wastewater raises concerns about the toxicological risks associated with its discharge and reuse. During the COVID-19 pandemic, widespread use of antivirals (ATVs), along with plastic gloves and masks, further contributed to pharmaceuticals in wastewater. Chlorination, commonly used for [...] Read more.
The presence of pharmaceuticals in wastewater raises concerns about the toxicological risks associated with its discharge and reuse. During the COVID-19 pandemic, widespread use of antivirals (ATVs), along with plastic gloves and masks, further contributed to pharmaceuticals in wastewater. Chlorination, commonly used for wastewater disinfection, may alter the toxicity of antivirals in the presence of microplastics (MPs) and complex organics in secondarily treated wastewater. To investigate this, synthetic secondary effluent containing Favipiravir (FAV) and Oseltamivir (OSE) was exposed to various chlorination conditions, both with and without MPs. The changes in the concentrations of FAV and OSE were measured using LC-MS/MS with isotopically labeled standards. Chlorination was more effective in removing Favipiravir (42 ± 4%) than Oseltamivir (26 ± 3%). The ecotoxicological effects were assessed on two species—Aliivibrio fischeri (a bacterium) and Enchytraeus crypticus (a soil invertebrate)—to evaluate potential impacts on aquatic and soil environments, though discharge of or irrigation with treated wastewater, respectively. Results indicated that chlorination of wastewater itself increased toxicity more significantly than the chlorination of antivirals to either species, suggesting that chlorination may not be as beneficial despite its cost-effectiveness. The effects of MPs in chlorinated wastewater on toxicity highlighted the importance of sample matrices in environmental toxicity studies. Full article
(This article belongs to the Section Environmental and Green Processes)
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24 pages, 1747 KiB  
Article
The Heterogeneity in the Relationships Between Psychological Drivers and Construction and Demolition Waste Management Intention and Behaviors Among Tunnel Construction Managers: Insights from Personality Profiles
by Yanjie Li and Guanfeng Yan
Sustainability 2025, 17(5), 2286; https://doi.org/10.3390/su17052286 - 6 Mar 2025
Viewed by 734
Abstract
Effective tunnel construction and demolition (C&D) waste management is a critical issue in the context of sustainable development, and C&D waste management measures guided by 3R principles (Reduce, Reuse, and Recycle) comply with the circular economy. In this study, an extended theory of [...] Read more.
Effective tunnel construction and demolition (C&D) waste management is a critical issue in the context of sustainable development, and C&D waste management measures guided by 3R principles (Reduce, Reuse, and Recycle) comply with the circular economy. In this study, an extended theory of planned behavior model based on the existing literature was proposed to identify the drivers of tunnel construction managers’ intention to implement effective waste management measures; then, the respondents were classified into four groups according to personality traits to explore the effects of personality profile on the heterogeneity in relationships between psychological drivers and C&D waste management intention and behaviors. The results show that all TPB constructs, policies, and environmental concern are significant predictors of managers’ intention to manage C&D waste properly. Then, considerable variance in the driving effects of various psychological drivers across different groups is witnessed. For the positive and temperate participants, subjective norms and policies are the most effective driving factors. However, PBC and environmental concern show a stronger relationship with the conservative and introverted participants’ intentions to adopt effective waste management measures. The findings are beneficial to developing corresponding management measures to promote effective C&D waste management. Full article
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15 pages, 2988 KiB  
Article
Thermostability Improvement of the Chitinase from Bacillus circulans for Efficient Chitin Oligosaccharide Production via Computational Design
by Jingwei Liu, Jie Xie, Si Wang, Hong Feng and Ganggang Wang
Biomolecules 2025, 15(3), 330; https://doi.org/10.3390/biom15030330 - 24 Feb 2025
Viewed by 1024
Abstract
The chitinase A1 from Bacillus circulans WL-12 (BcChiA1) exhibits promising potential for producing chitin oligosaccharides (CHOs), while its application is limited by its poor thermal stability. In this study, a set of thermostable variants were obtained by modifying BcChiA1 using a comprehensive strategy [...] Read more.
The chitinase A1 from Bacillus circulans WL-12 (BcChiA1) exhibits promising potential for producing chitin oligosaccharides (CHOs), while its application is limited by its poor thermal stability. In this study, a set of thermostable variants were obtained by modifying BcChiA1 using a comprehensive strategy based on a computer-aided design. A combination of five beneficial single-point mutations (S67G/K177R/A220V/N257Y/N271E) to BcChiA1 generated a markedly improved variant, Mu5. Mu5 exhibited a half-life of 295 min at 60 °C, which was 59 times higher than that of BcChiA1. Furthermore, Mu5 was reused for chitin conversion, releasing 86.14 ± 3.73 mM of CHOs after five reaction cycles. Molecular dynamics simulation and structural analysis revealed that these enhancements were driven by increased structural rigidity and compactness, resulting in a protein conformation that was less prone to thermal denaturation. This combined approach through computational design yielded a thermostable BcChiA1 variant, potentially facilitating CHOs production in economical way. Full article
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