Search Results (6,290)

Milling pretreatment is a crucial step in the bioconversion of lignocellulosic biomass such sugarcane bagasse because it facilitates access to cellulose for subsequent chemical treatments. However, most experiments have been conducted at the laboratory scale, where it has been identified that high energy is required for the processing of biomass. For this reason, it is proposed to implement the screw extruder technique for the processing of cellulose. This article focuses on the characteristics, types, and applications of milling pretreatment for sugarcane bagasse, with a particular emphasis on its role in lignin removal and the milling design. Milling pretreatment reduces the particle size of lignocellulose biomass through compression shear and tearing mechanisms, which enhances the accessibility of cellulose and hemicellulose to enzymes and chemicals, thereby improving the efficiency of bioconversion processes. Innovative mathematical modeling, a mechanical design in a CAD application, and an FEA analysis of the milling pretreatment equipment are presented, providing insights into the design and optimization of milling pretreatment processes. This article presents an innovative potential system for milling pretreatment in sugarcane bagasse for the production of bioethanol, heat and power, and other value-added products, contributing to a more sustainable and circular economy. Full article

The circular economy, as a new model of waste management through energy self-sufficiency and valorisation, can be applied to wastewater treatment plants (WWTPs). Screening waste from WWTP pretreatment is the only waste that is not energetically recovered and thus constrains the achievement of zero waste. Previous studies demonstrated the technical feasibility of producing solid recovered fuel (SRF) from this waste. Environmental benefits, including waste reduction, resource conservation, or reduced greenhouse gas emissions are analysed in this work. Environmental impact is quantified using the life cycle assessment (LCA) methodology through the SimaPro 9.2. software and the CML-IA baseline v3.08 impact methodology, that propose 11 impact categories. Five scenarios were established to compare current landfill disposal with the production of densified and non-densified SRF using solar and thermal drying. Within the system boundaries studied, from waste generation to SRF production, results show that landfill is the most environmentally damaging option while producing non-densified SRF using solar drying is the most environmentally viable scenario. Full article

A versatile and popular Cucurbitaceous vegetable, pumpkin has recently gained much attention because of its variety of phytochemicals and health advantages. Pumpkins are a type of winter squash, traditionally with large, spherical, orange fruits and a highly nutrient food. Pumpkin by-products comprise various parts, such as seeds, peels, and pulp residues, with their bioactive composition and many potential benefits poorly explored by the food industry. Pumpkin and their by-products contain a wide range of phytochemicals, including carotenoids, polyphenols, tocopherols, vitamins, minerals, and dietary fibers. These compounds in pumpkin by-products exhibit antioxidant, anticancer, anti-inflammatory, anti-diabetic, and antimicrobial properties and could reduce the risk of chronic diseases. This comprehensive review aims to provide a detailed overview of the phytochemicals found in pumpkin and its by-products, along with their extraction methods, health benefits, and diverse food and industrial applications. This information can offer valuable insights for food scientists seeking to reevaluate pumpkin’s potential as a functional ingredient. Reusing these by-products would support integrating a circular economy approach by boosting the market presence of valuable and sustainable products that improve health while lowering food waste. Full article

Urban buildings consume raw material and energy, and they produce waste and greenhouse gasses. Sustainable urban development strategies aim to reduce these. Using the case study of buildings in Vienna, this article evaluates the impact of a defined urban development pathway on the heating energy demand, greenhouse gas emissions, and total material requirement of buildings in Vienna for 2021–2050. Furthermore, the impact of recycling to reduce the total material requirement and to increase the circular material use rate is evaluated. The results show that the heating energy demand can be reduced to meet the targets of Vienna’s sustainable development strategy. The same does not count for greenhouse gas emissions. To meet the targets for the latter, the renovation of old buildings by thermal insulation should be expanded and heating systems substituted. With respect to the total material requirement, the recycling of demolition waste from buildings in Vienna to produce secondary raw materials for buildings in Vienna can help to achieve the reduction targets of Vienna’s sustainable development strategy so that in the year 2050, the material footprint is only 44% of the value of the year 2019. Since there is a contradiction between the total material requirement and the circular material use rate, the latter has to be discussed for its use as a circular economy indicator, since the aim of circular economy is not to produce as much recycling materials as possible, but to reduce resource consumption to a sustainable level. Full article

This study investigates the removal of heavy metals, particularly copper and nickel, from acidic aqueous solutions using the weakly base polymeric chelating resin Dowex M-4195. The research conducts comprehensive cost–benefit and statistical analyses of various kinetic and isotherm adsorption models. The results show that the PSO and general order models provide high accuracy for the Cu²⁺ adsorption kinetics, while the Avrami fractional order model excels for Ni²⁺. In terms of the isotherm models, the Langmuir and Jovanovic models are highly accurate for both metals, with the Toth model being particularly effective for Ni²⁺ due to its ability to account for surface heterogeneity and multi-layer adsorption. This study also reveals that the kinetic adsorption process is more economically beneficial than the isotherm adsorption process, highlighting the importance of model selection for optimizing heavy metal removal. Incorporating circular economy principles, this research emphasizes the sustainability of using regenerable and reusable adsorbents like Dowex M-4195. The findings provide valuable insights for designing efficient adsorption systems, promoting environmental sustainability, and ensuring public health safety. Full article

The transition towards renewable energy is not as impressive as expected when considering the wide array of efforts undertaken. Energy-abundant countries do not have sufficient stimuli to curb the use of fossil fuels; some of them even work on increasing international supply. Greenhouse gas emissions remain high. As the world population grows, more attention must be devoted to the transition towards renewables. This transition requires additional resources and leaves behind waste that must be recycled. Without a circular economy, the transition towards renewable energy will require extra power, resulting in a spiral that is very detrimental to the environment of our planet. This paper provides a picture of the current situation, discusses tendencies, and systemizes issues that must be tackled. Full article

Arthrospira platensis holds promise for biotechnological applications due to its rapid growth and ability to produce valuable bioactive compounds like phycocyanin (PC). This study explores the impact of salinity and brewery wastewater (BWW) on the mixotrophic cultivation of A. platensis. Utilizing BWW as an organic carbon source and seawater (SW) for salt stress, we aim to optimize PC production and biomass composition. Under mixotrophic conditions with 2% BWW and SW, A. platensis showed enhanced biomass productivity, reaching a maximum of 3.70 g L⁻¹ and significant increases in PC concentration. This study also observed changes in biochemical composition, with elevated protein and carbohydrate levels under salt stress that mimics the use of seawater. Mixotrophic cultivation with BWW and SW also influenced the FAME profile, enhancing the content of C16:0 and C18:1 FAMES. The purity (EP of 1.15) and yield (100 mg g⁻¹) of PC were notably higher in mixotrophic cultures, indicating the potential for commercial applications in food, cosmetics, and pharmaceuticals. This research underscores the benefits of integrating the use of saline water with waste valorization in microalgae cultivation, promoting sustainability and economic efficiency in biotechnological processes. Full article

Considering a circular economy perspective, this study evaluates the possible effect of targeted short-term supplementation with Withania somnifera L. (WS; Ashwagandha) on ram’s seminal quality, socio-sexual behaviors, and blood constituents. Black Belly rams (n = 20) received a basal diet comprising feed-leftovers from dairy cows in the north-arid Mexico (i.e., Comarca Lagunera CL). The experimental units, with proven libido and fertility, were homogeneous in terms of age (3.41 ± 0.21 yr.), live weight (LW; 53.8 ± 3.3 kg), body condition (BC; 2.96 ± 0.01 units), initial sperm concentration (2387 ± 804 × 10⁶), and viability (23.9 ± 15.6%). Rams were randomly assigned during the transition reproductive period (i.e., May to Jun; 25° NL) to three treatment groups: non-supplemented control group (CONT; n = 6), low WS-supplemented (LWS; i.e., 100 mg kg LW⁻¹ d⁻¹ × 40 d; n = 7), and high-WS-supplemented (HWS; i.e., 200 mg kg LW⁻¹ d⁻¹ × 40 d; n = 7). The basal leftover diet was offered twice daily (0700 and 1600 h); the experimental period (EP) lasted 47 d. No differences (p > 0.05) among treatments occurred regarding LW and BCS at the onset of the EP. Whereas the greater scrotal circumference (SCRC, cm) arose in the LWS and CONT rams, an increased ejaculated volume (VOLEJA, mL) occurred in the WS-rams. A total of 5/9 (i.e., 55%) appetitive and 3/3 (i.e., 100%) consummatory sexual behaviors favored (p < 0.05) the WS-rams, particularly the HWS rams, towards the final EP. The same was true (p < 0.05) regarding the hemogram variables white blood cell count (×10⁹ cells L⁻¹), hemoglobin concentration (g dL⁻¹), and medium corpuscular volume (fL). This study, based on a rethink–reuse–reduce enquiry approach, enabled connectedness between two noteworthy animal systems in the CL: dairy cows and meat sheep schemes. Certainly, the use of dairy cow feed-leftovers aligned with the short-term supplementation with WS promoted enhanced testicular function, augmented seminal volume, and an increased sexual behavior in Black Belly rams in northern Mexico. Finally, while our research outcomes should enhance not only the resilience and sustainability of sheep production and the well-being of sheep-producers and their families, it may also embrace clinical translational applications. Full article

Lithium-ion batteries are pervasive in contemporary life, providing power for a vast array of devices, including smartphones and electric vehicles. With the projected sale of millions of electric vehicles globally by 2022 and over a million electric vehicles in Europe alone in the first quarter of 2023, the necessity of securing a sustainable supply of lithium-ion batteries has reached a critical point. As the demand for electric vehicles and renewable energy storage (ESS) systems increases, so too does the necessity to address the shortage of lithium batteries and implement effective recycling and recovery practices. A considerable number of electric vehicle batteries will reach the end of their useful life in the near future, resulting in a significant increase in the number of used batteries. It is of paramount importance to accurately identify the manufacturer and model of cylindrical batteries to ascertain their State of Health (SoH) and guarantee their efficient reuse. This study focuses on the automation of the identification of cylindrical cells through optical character recognition (OCR) and the analysis of the external color of the cell and the anode morphology based on computer vision techniques. This is a novel work in the current limited literature, which aims to bridge the gap between industrialized lithium-ion cell recovery processes and an automated SoH calculation. Accurate battery identification optimizes battery reuse, reduces manufacturing costs and mitigates environmental impact. The results of the work are promising, achieving 90% accuracy in the identification of 18,650 cylindrical cells. Full article

With the “Talents Internship program” established by the Austrian Research Promotion Agency (FFG, Österreichische Forschungsförderungsgesellschaft), 14- to 17-year-old students from various school types visited the Natural History Museum and the Kuratorium Pfahlbauten in summer 2022 to gain practical experience in research. The internship focused on a sustainability approach, discussing recycling methods, the sustainable use of resources and the circular economy in prehistory. The UNESCO World Heritage “Prehistoric Pile Dwellings around the Alps” was used as a research area for the project. The project also aimed to make the content developed by the students available to the public as a digital media tool. The pupils brought an illustration of a prehistoric lake shore settlement to life and created an interactive image available at the website of Kuratorium Pfahlbauten. Various scenes of the illustration have been augmented with animations created by the students of HTL Spengergasse in Vienna. Students from federal secondary schools from Vienna (Stubenbastei) and Upper Austria (Traun) researched the information about the objects and wrote texts that, as a description of the animated videos, introduce the users to the prehistoric artifact and explain the recycling process behind it. The students worked independently using the scientific literature, 140-year-old inventory books and 6000-year-old objects from the collection of the Natural History Museum Vienna. The activities and the supporting program within the internship were recorded by the students in blog posts, available at the Pfahlbauten-Blog. The co-creative approach of the FFG Talent Internship made it possible to introduce a group of school students to the process of scientific work and the communication of results. It was honored with the Creative App Award at CHNT 2023. Full article

Given the current highest demand in history for raw materials, there is a growing demand for the recovery of key metals from secondary sources, in order to prevent metal depletion and to reduce the risk of toxic discharges into the environment. This paper focuses on the current nature-based solutions (i.e., biomining and bioleaching) applied to resource recovery (metals) from solid matrices. Biomining exploits the potential of microorganisms to facilitate the extraction and recovery of metals from a wide range of waste materials as an interesting alternative, replacing primary raw materials with secondary material resources (thus improving metal recycling rates in the context of the circular economy). Special attention was paid to the analysis of metal biomining from a process sustainability perspective. In this regard, several supporting tools (e.g., life cycle assessment, LCA), developed to assist decision-makers in the complex process of assessing and scaling-up remediation projects (including biomining), were discussed. The application of LCA in biomining is still evolving, and requires comprehensive case studies to improve the methodological approach. This review outlines the fact that few studies have focused on demonstrating the environmental performance of the biomining process. Also, further studies should be performed to promote the commercial opportunities of biomining, which can be used to recover and recycle metals from solid matrices and for site remediation. Despite some important disadvantages (poor process kinetics; metal toxicity), biomining is considered to be a cleaner approach than conventional mining processes. However, implementing it on a large scale requires improvements in regulatory issues and public acceptance. Full article

The genus Trichoderma is widely recognized for its ability to secrete lignocellulosic enzymes, establishing it as a crucial technological resource for the bioconversion of agro-industrial waste biomass via fermentation. This review explores the potential of utilizing lignocellulosic waste from diverse industries as a sustainable nutrient source for producing Trichoderma spp. and various desirable metabolites via fermentation. Significant emphasis is placed on the enzymatic activities of Trichoderma species in two critical stages of second-generation biofuel production. Firstly, in the pre-treatment stage to break down complex polysaccharides of lignocellulosic biomass, thereby enhancing production efficiency and yield, and, secondly, during the hydrolysis process to produce fermentable sugars essential for biofuel production. Additionally, this review discusses other applications of Trichoderma fermentation, such as enhancing animal feedstock nutrition and employing its spores as biocontrol agents. Ongoing research efforts are directed at optimizing fermentation protocols, identifying suitable waste substrates, and genetic manipulation of strains to enhance the economic viability of Trichoderma’s biotechnological applications. This manuscript contributes to the field of circular biotechnology by offering a detailed review of recent progress on the integration of agro-industrial waste materials in Trichoderma-based bioconversion technologies, highlighting both current achievements and future research directions necessary to enhance the economic and environmental sustainability of waste biomass utilization. Full article

The increasing concern over environmental sustainability has prompted various industries to reassess their practices and explore greener alternatives. Dentistry, as a significant contributor to waste generation, is actively seeking methods to minimize its environmental footprint. This paper examines the environmental implications of clear aligner therapy (CAT) in orthodontics and explores strategies to prioritize sustainability in aligner manufacturing and usage. CAT has gained popularity as a viable alternative to traditional fixed appliances due to advancements in biomaterials and computer-aided design (CAD) and manufacturing (CAM) technologies. The global market for clear aligners is expanding rapidly, with significant growth projected in the coming years. To address these challenges, this paper proposes adopting the principles of reduce, reuse, recycle, and rethink (4Rs) in orthodontic practices. Strategies such as minimizing resource consumption, incorporating recycled materials, and promoting proper aligner disposal and recycling can significantly reduce environmental harm. This paper explores emerging technologies and materials to mitigate the environmental impacts of CAT. Additionally, initiatives promoting aligner recycling and repurposing offer promising avenues for reducing plastic waste and fostering a circular economy. In conclusion, while CAT offers numerous benefits in orthodontic treatment, its environmental impact cannot be overlooked. By implementing sustainable practices and embracing innovative solutions, the orthodontic community can contribute to a more environmentally conscious future while continuing to provide quality care to patients. Full article

The technological and environmental challenges promoted by the European Commission (EC) follow its objectives to minimise waste, ensure the rational use of resources and energy, use raw materials more efficiently, and increase recovery and recycling. The new hierarchy of handling products and waste has been a key challenge of the circular economy, enhancing the involvement of both businesses and consumers. The life cycle assessment (LCA) is an environmental management technique that makes it possible to assess the environmental impact of a product, a process, an industry, or even an entire sector of the economy. It is used worldwide with great success to study the various stages of technology, ensuring environmental safety. The experience of Polish and foreign research centres confirms the possibility of using the LCA technique to support the environmental risk assessment of technological innovations, therefore the LCA technique has been used to study the environmental impact of potential technologies for producing flocculants from polymer waste. LCA of newly synthesised flocculants has shown that sourcing flocculants from waste phenol–formaldehyde resins is highly beneficial to the environment due to the high toxicity of waste resins that produce phenol when exposed to physical factors. Full article

The uptake of a circular economy (CE) in the building sector is challenging, primarily due to the complexity associated with the design process and the dynamic interaction among architects, engineers, and construction (AEC) stakeholders. The standard and typical design process and construction methods raise concerns about building life cycles. Buildings should not only fulfill current needs, but one also needs to consider how they will function in the future and throughout their lifetime. To address these complexities, early planning is required to guide designers in holistically applying systems thinking to deliver CE outcomes. This paper outlines a critical review of CE implementation in buildings, with a proposed trifecta of approaches that significantly contribute to the development of circular buildings (CBs). The findings outline a proposed visualized framework with a conceptual formula that integrates CE design strategies to simplify and enhance AEC stakeholders’ perception of the circularity sequence in buildings. By strategically integrating loop-based strategies with the value retention process (VRP) and design for X (DFX) strategies, along with efficient assessment tools and technologies, it becomes feasible to embrace a CE during the design phase. The outcome of this review informs AEC stakeholders to systematically and strategically integrate the critical dimensions of a CE throughout the building life cycle, striking a balance between environmental concern, economic value, and future needs. Full article