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This review explores circular economy principles in regard to ethanol production from paper-mill sludge. Environmental sustainability and renewability over fossil fuels make second generation ethanol an attractive energy source in a rapidly growing population and consumption world. Paper sludge (PS), a by-product of the pulp and paper (P&P) industry, can no longer be recycled for paper production and is mainly disposed of in landfills. Therefore, it poses a major environmental challenge. However, it has shown potential as a valuable raw material for ethanol production, along with other pulp and paper products, due to its abundant availability and high cellulosic content. This waste-to-energy (WtE) technology for ethanol production is proposed as an alternative, aligning with circular economy concepts to maximize resource efficiency and minimize waste. This review underlines the circular economy aspects of bioethanol production within paper mill sludge management systems. Circular economy principles applied to ethanol production from PS offer a promising avenue for sustainable biofuel development that not only addresses waste management challenges but also enhances the overall environmental performance of biofuel production. Furthermore, economic benefits are described, highlighting the potential for job creation and community development. [ABSTRACT FROM AUTHOR]

Though paper is an environmentally friendly alternative to plastic as a packaging material, it lacks antibacterial properties, and some papers have a low resistance to oil or water. In this study, a multifunctional paper-coating material was developed to reduce the use of plastic packaging and enhance paper performance. Natural cellulose nanocrystals (CNCs) with excellent properties were used as the base material for the coating. The CNCs were functionalized into dialdehyde CNCs (DACNCs) through periodate oxidation. The DACNCs were subsequently complexed using erythrosine as a photosensitizer to form an erythrosine–CNC composite (Ery-DACNCs) with photodynamic inactivation. The Ery-DACNCs achieved inactivations above 90% after 30 min of green light irradiation and above 85% after 60 min of white light irradiation (to simulate real-world lighting conditions), indicating photodynamic inactivation effects. The optimal parameters for a layer-by-layer dip coating of kraft paper with Ery-DACNCs were 4.5-wt% Ery-DACNCs and 15 coating layers. Compared to non-coated kraft paper and polyethylene-coated paper, the Ery-DACNC-coated paper exhibited enhanced mechanical properties (an increase of 28% in bursting strength). More than 90% of the bacteria were inactivated after 40 min of green light irradiation, and more than 80% were inactivated after 60 min of white light irradiation. [ABSTRACT FROM AUTHOR]

To ensure development sustainability, the linear economic approach is being transformed into a cyclical model. For the pulp and paper industry (PPI), which occupies a significant place in the Russian economy, the shift of circular principles to the field of bioeconomics is becoming more important. This requires the development of basic biotechnological approaches implemented in closed cycles (biorefining). The aim of this study was to develop the biotechnological foundations of the circular economic system of the pulp and paper industry. To achieve the goal, the factors for the implementation of the circular mechanism in the pulp and paper industry were established. The composition of pulp and paper waste was systematized, taking into account the places of their occurrence; the directions and forms of the biorefining of pulp and paper secondary renewable resources were determined; and the principal possibility of obtaining bioethanol, based on the whole complex of sugars from cellulose production wastes, is shown. A wide range of general scientific methods was involved (analysis, synthesis, classification, modeling, etc.). Statistical methods were used to process experimental results in the field of pulp and paper waste bioconversion. The biotechnologies involved included methods of destruction, detoxification, and conversion of useful resources into secondary raw materials and final products. From the standpoint of the environmental approach, there are serious efficiency imbalances in the pulp and paper industry, which justify the implementation of circular mechanisms for organizing economic systems. The overall efficiency is ensured by the use of renewable resources and obtaining environmental effects. Algorithms and parameters of green biotechnological regulations for pulp and paper industry waste recycling provide the possibility of microbiological production of a complex of products: biocomposites, bioplastics, medical products, fertilizers, feed additives, vitamin supplements, and bioenergy resources. A strategy for the efficient biochemical processing of pulp and paper waste into green ethanol was determined. The possibility of increasing the efficiency of alcoholic fermentation using various biocatalysts was experimentally confirmed. The technological features of this method, associated with the need for microaerobic fermentation modes, were determined. [ABSTRACT FROM AUTHOR]

The valorization of wastes as an alternative or secondary raw material in various products and processes has been a solution for the implementation of sustainability, a safer environment, and the concept of circular economy in the efficient use and management of natural resources. To promote sustainability through a circular economy approach, this work tries to demonstrate the environmental gains that are obtained by bringing together, in an industrial symbiosis action, two large industrial sectors (the pulp and paper and the road pavement sectors) responsible for generating large amounts of wastes. A sustainability assessment, based on a life cycle and circular economy approach, is presented here, and discussed using a simple case study carried out on a real scale. Two wastes (dregs and grits) from the pulp and paper industry (PPI) were used to partially replace natural fine aggregates in the production of bituminous mixtures used on the top surface of road pavements. The impacts at a technical, environmental, economic, and social level were assessed and it was shown that this simple waste valorization action is not only positive for the final product from a technical point of view, but also for the environment, causing positive impacts on the different sustainability dimensions that were evaluated. [ABSTRACT FROM AUTHOR]

In order to explore the methods of recycling waste paper, reduce environment pollution, and develop a circular economy, the application of waste corrugated paper to the strengthening of polylactic acid (PLA) was studied. Plant fiber from waste corrugated paper (WCPF) was used to prepare WCPF/PLA composite via co-extrusion. The WCPF was extracted from the waste corrugated paper by beating in a Valli beating machine and grinding in a disc grinder. KH-550 coupling agent was used to modify the surface of WCPF to improve the interface adhesive strength between the WCPF and PLA matrix. The effects of the contents of WCPF and KH-550 coupling agent on the mechanical properties, microstructure, crystallization properties, and thermostability of the WCPF/PLA composite were studied. The results show that the WCPF can be well separated from each other. The WCPF can be uniformly dispersed in the PLA matrix through a co-extrusion process. WCPF can increase the mechanical strength and deformation resistance ability of WCPF/PLA composite, and KH-550 coupling agent can further improve that of the WCPF/PLA composite. This study is of obvious significance to the recycling of waste paper and the development of a circular economy. [ABSTRACT FROM AUTHOR]

Thin film transistors on paper are increasingly in demand for emerging applications, such as flexible displays and sensors for wearable and disposable devices, making paper a promising substrate for green electronics and the circular economy. ZnO self-assembled thin film transistors on a paper substrate, also using paper as a gate dielectric, were fabricated by pulsed electron beam deposition (PED) at room temperature. These self-assembled ZnO thin film transistor source–channel–drain structures were obtained in a single deposition process using 200 and 300 µm metal wires as obstacles in the path of the ablation plasma. These transistors exhibited a memory effect, with two distinct states, "on" and "off", and with a field-effect mobility of about 25 cm2/Vs in both states. For the "on" state, a threshold voltage (Vth on = −1.75 V) and subthreshold swing (S = 1.1 V/decade) were determined, while, in the "off" state, Vth off = +1.8 V and S = 1.34 V/decade were obtained. A 1.6 μA maximum drain current was obtained in the "off" state, and 11.5 μA was obtained in the "on" state of the transistor. Due to ZnO's non-toxicity, such self-assembled transistors are promising as components for flexible, disposable smart labels and other various green paper-based electronics. [ABSTRACT FROM AUTHOR]

To improve the recycle value of waste paper and promote circular economic development, waste corrugated paper fiber (WCPF) was used as a reinforcing agent to prepare waste corrugated paper fiber/polylactic acid (WCPF/PLA) composites via dichloromethane solvent which can be reused. The WCPF in the waste corrugated paper is extracted by beating in a Valli beating machine for different time lengths and grinding in a disc grinder. The effects of beating time and the content of WCPF on the microstructure, mechanical properties, thermal decomposition process, and crystallization properties of the WCPF/PLA composite were studied. The result shows that the WCPF can be well separated from each other and can be evenly dispersed in the PLA matrix. When 25 wt% WCPF which was beat for 30 min was used, the composite has the greatest improvement in tensile property. This study provides a new process for the recycling of waste paper in the application of polymer reinforcement. The research on waste paper fiber and degradable polymer composite is of great significance for reducing environmental pollutants and developing circular economy. [ABSTRACT FROM AUTHOR]

The pulp and paper industry (PPI) is a major contributor to the global economy, but it also poses a challenge for waste disposal, as it generates large amounts of several waste streams. Among these, paper rejects are generated during the papermaking process and could account for up to 25% of the produced paper. Moreover, hundreds of millions of tons of paper are produced annually that end up in landfills if not burnt or recycled. Furthermore, the PPI significantly contributes to climate change and global warming in the form of deforestation and water and air pollution. Therefore, the impact of this industry on the sustainability of natural resources and its adverse environmental health effects requires special attention. This review focuses on discussing the sustainable routes to utilize paper waste and rejects from the PPI towards a circular economy. At first, it discusses the industry itself and its environmental impact, followed by the possible sustainable approaches that can be implemented to improve papermaking processes as well as waste management systems, including paper recycling. The literature indicates that paper recycling is crucial because, if appropriately designed, it significantly lowers greenhouse gas emissions, water and resources consumption, and manufacturing costs. However, several concerns have surfaced about the different chemicals that are used to improve recycling efficiency and recycled paper quality. Furthermore, paper recycling is limited to up to seven times. This review, therefore, goes on to highlight several sustainable waste management routes for paper waste utilization other than recycling by emphasizing the concept of converting paper waste and rejects into energy and high-value materials, including biofuels, biohydrogen, biomethane, heat, nanocellulose, hydrochar, construction materials, and soil amendments. Both the benefits and shortcomings of these waste management routes and their applications are discussed. It becomes clear from this review that sustainable management solutions for paper waste and rejects are implementable, but further research and development are still needed. [ABSTRACT FROM AUTHOR]

A growing research interest currently exists in the use of paper as a building material. This work aims to present the results of a measurement campaign developed on innovative waste paper-based building components. The research was carried out in Southern Italy and used some local by-product aggregates. Three different mixture designs were developed in the laboratory by adding three kinds of biomass to a pulp paper blend: fava bean residues (FB), sawdust powder (SP) and coffee grains (CG) extracted from exhausted chaffs. A physical characterization was carried out measuring the bulk density and bulk porosity. Scanning Electron Microscopy (SEM) analysis of the single aggregates was followed by a microstructure analysis of the final components. Bulk density evaluation showed a range between 200 and 348 kg·m−3. Furthermore, thermal performances were measured; the thermal conductivity of the experimented samples ranged from 0.071 to 0.093 W·m−1·K−1, thus it is possible to classify the tested materials as thermal insulators. Moreover, the acoustic properties were evaluated and tested. The normal incidence sound absorption coefficient was measured by the impedance tube on cylindrical specimens. In general, a different behavior was observed between the upper and lower base of each specimen due to the manufacturing process and the shrinkage caused by the different interactions occurring between the aggregates and the pulp paper waste; for example, the presence of sawdust reduced shrinkage in the final specimens, with consequent smaller physical variations among the two faces. The correlation existing between the manufacturing process and the microstructural properties was also investigated by the estimation of the non-acoustical parameters using the inverse method and taking into account the JCA (Johnson, Champoux and Allard) model as a reference. [ABSTRACT FROM AUTHOR]

To encourage proper waste management for electrical and electronic devices (e-waste), it is necessary to invest heavily in the development of recycling technologies. One way to improve the process is to automate separating the shredded parts of e-waste using a robot. This paper's literature review, utilizing the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) framework, showcases potential robotic technologies for e-waste separation. However, the intricate design of these devices can pose significant challenges in their implementation. Various legal, organizational, and sociological obstacles have left Serbia's e-waste management practice underdeveloped, resulting in an unsatisfactory recycling rate. In this paper, we examined the possibility of using robots in the precise example of recycling refrigerators in a recycling center in Eastern Serbia, concluding that such a solution would have multiple positive effects, both on the employees and the working environment, on the operations of the recycling center itself, and on increasing the e-waste recycling rate in the country. [ABSTRACT FROM AUTHOR]

Featured Application: Papermaking industry and technology. Innovative applications of vegetal residues. This study examines the potential of four invasive plant species, both arboreal and herbaceous, within the riparian forest of the Umia River in Galicia, a common ecosystem in northern Spain. These invasive species (Arundo donax, Phytolacca americana, Eucalyptus globulus, and Tradescantia fluminensis) were collected and assessed for their suitability as an alternative source of pulp and paper materials for the paper industry to mitigate the environmental impacts associated with conventional cellulose fiber production from harmful monocultures. Cellulosic material from leaves, bark, and/or stems of each of the selected species was isolated from lignin and hemicelluloses through kraft pulping processes. Resulted fibers and pulps were analyzed visually, morphologically, chemically, and mechanically to evaluate their papermaking properties. To compare these properties with those of commercially available pulp, test sheets were concurrently produced using commercial bleached Eucalyptus cellulose. The findings reveal that the employed fibers exhibit promising characteristics for artistic paper production. Regarding the pulp, two refining times were tested in a PFI machine, and the Schopper–Riegler degree was measured. Paper sheets underwent various tests to determine thickness, basis weight, apparent volume, apparent density, permeability, and chemical composition, as well as microscopic optical and morphological properties. The fibers obtained from the waste derived from the removal of invasive exotic species and biodiversity control present a viable and intriguing alternative for decentralized paper production, yielding noteworthy results for the creative sector. This research highlights the potential of harnessing invasive species for sustainable and innovative paper manufacturing practices. [ABSTRACT FROM AUTHOR]

Featured Application: One of the main technological challenges within Circular Economy strategies is to minimize the environmental impact of plastic packaging. In this regard, the use of PHBV films to coat paper sheets represents a highly sustainable strategy to produce food packaging multilayer structures with improved mechanical and barrier properties. This work reports on the development and performance evaluation of newly developed paper sheets coated, on both sides, with thin films of biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) for applications of food packaging. For this, PHBV/paper/PHBV multilayers were first prepared by the thermo-sealing technique, optimizing the process variables of temperature and time. Thereafter, the multilayer sheets were characterized in terms of their morphological, optical, thermal, mechanical, and barrier properties and compared with equivalent paper structures double coated with high-barrier multilayer films of petrochemical polymers. The results indicated that the double coatings of PHBV successfully improved the mechanical resistance and ductility, protected from moisture, and also reduced the aroma and oxygen permeances of paper, having a minimal effect on its optical and thermal properties. Finally, the compostability of the resultant multilayer sheets was analyzed, confirming that the presence of the PHBV coatings slightly delayed the aerobic biodegradation and disintegration of paper. [ABSTRACT FROM AUTHOR]

Invasive plant species can impede the establishment and growth of native plants and affect several ecosystem properties. These properties include soil cover, nutrient cycling, fire regimes, and hydrology. Controlling invasive plants is therefore a necessary, but usually expensive, step in restoring an ecosystem. The sustainability of materials with an emphasis on the use of local resources plays an important role in the circular economy. The use of alternative fibers from invasive plants promotes local production in smaller paper mills that offer the protection of local species and the reduction of waste and invasive plants. A synthesis of the literature is needed to understand the various impacts of invasive plants and their practical control in the context of papermaking applications and to identify associated knowledge gaps. To improve our understanding of the practical application of invasive species in the paper industry, we reviewed the existing literature on invasive plant species in the area of fiber production, printability, coating solution production, dyes, and extracts, and collected information on the major invasive plant species in Europe and the methods used for various applications. [ABSTRACT FROM AUTHOR]

Packaging appearance is important in a competitive market. Designers strive to create products that attract customers and often use laminated packaging, due to the attractive appearance and quality characteristics of the material. The circular economy in the recycling of cardboard packaging helps to reduce waste, saves natural resources and increases the quality of the environment. All of the above contributes to sustainable production, but the quality and properties of the obtained recycled paper materials should not be ignored. Recycling of laminated cardboard packaging often has a negative impact on the quality of recycled paper, due to the formation of sticky particles that can affect the optical properties of recycled paper and the efficiency of the recycling process. This article provides insight into the influence of each stage of production of packaging intended for pharmaceutical products on the properties and characteristics of recycled paper. The standard INGEDE 11 deinking method was used to remove dyes and other impurities from the pulp. The obtained optical results of the characteristics of recycled laboratory sheets obtained from laminated and non-laminated cardboard samples were compared in order to determine the impact of each stage of box production on the quality of the paper pulp. The acquired knowledge can be applied in the design phase of a more sustainable product, and laminated materials can be used in luxury products or to increase the functionality of the packaging. Designing for recycling will contribute to an increase in the quality of the obtained paper mass, which is directly related to an increase in the productivity of recycling and the sustainability of the packaging production process. [ABSTRACT FROM AUTHOR]

Finding eco-friendly products that are beneficial to the environment and serve as tools for sustainable development is a contemporary challenge. This work illustrates the recovery of bio-waste-based materials, which not only improve the hygrothermal properties of gypsum but also promote the paper and wood recycling processes in a circular economy approach. The samples were subjected to tests for density, water absorption, ultrasonic pulse velocity, flexural strength, compressive strength, and thermophysical property characterization. A statistical analysis of variance was used to study the impact of waste on the physico-mechanical behavior of gypsum, leading to the development of predictive models that can be used to predict and optimize the performance of bio-composites in various applications. The results revealed a reduction in mechanical strength with the addition of waste, but the samples still exhibit superior insulation properties, surpassing commonly used standard boards. By adding ouate and wood wastes to a mass of 20% in its natural state, the gypsum becomes lighter and acts as a better insulator with a reduced density, thermal conductivity, and ultrasound velocity of up to 50%, 57%, and 83%, respectively. These findings show the significant implication of reducing environmental impacts while contributing to the promotion of sustainable building practices, both in new construction projects and in building renovations. [ABSTRACT FROM AUTHOR]

Interest towards cellulose nanofibers obtained from virgin and waste sources has seen a significant growth, mainly thanks to the increasing sensitivity towards the concept of circular economy and the high levels of paper recycling achieved in recent years. Inspired by the guidelines of the green building industry, this study proposes the production and characterization of TEMPO-oxidized and homogenized cellulose nanofibers (TOHO CNF) from different sources and their use as additives for earth plasters on two different raw earth samples, characterized by geotechnical laboratory tests and mineralogical analysis: a high-plasticity clay (T2) and a medium-compressibility silt (ABS). Original sources, including those derived from waste (recycled cardboard and paper mill sludge), were characterized by determining chemical content (cellulose versus ashes and lignin) and fiber morphology. TOHO CNF derived from the different sources were compared in terms of nanofibers medium diameter, crystallinity degree, thermal decomposition and oxidation degree, that is the content of carboxylic groups per gram of sample. Then, a preliminary analysis of the influence of CNF on earth plasters is examined. Adhesion and capillary absorption tests highlighted the effect of such nanofibers on blends in function of two factors, namely the cellulose original source and the oxidation degree of the fibers. In particular, for both earth samples, T2 and ABS, a significant increase in adhesion strength was observed in the presence of some TOHO CNF additives. As far as capillary sorption tests, while an undesired increase in water adsorption was detected for T2 compared to the control, in the case of ABS, a significant reduction in water content was measured by adding TOHO CNF derived from recycled sources. These results pave the way for further in-depth investigation on the role of TOHO CNF as additives for earth plasters. [ABSTRACT FROM AUTHOR]

Waste valorisation as secondary or alternative raw materials in several sectors products and processes has been an important way to implement a more sustainable and circular way to manage the efficient use of natural resources. This action contributes not only to save natural resources but also to prevent sending large amounts of wastes, some of them dangerous, to landfill disposal, creating a major environmental, economic and social impact. To promote circular economy, this work attempts to demonstrate the environmental gains in a competitive way, by bringing together in an industrial symbiosis action, two large producing sectors (the pulp and paper industry and concrete construction sector), which are also able to consume significant amounts of resources and to generate large amounts of wastes. A sustainability evaluation based on a life cycle and circular approach is presented and discussed using a simple case study performed at real industrial scale. The lime ash waste from the pulp and paper industry is used to replace 100% of the natural filler used in precast concrete production and the impacts and benefits from the technical, environmental, economic and social level were assessed. It was demonstrated that this simple action causes positive impacts in the evaluated dimensions of sustainability without causing any changes in production time and causes no degradation on relevant concrete properties. [ABSTRACT FROM AUTHOR]

In this work, different alternatives to conventional tertiary treatment of pulp and paper (P&P) wastewater (WW), i.e., physicochemical coagulation-flocculation, were investigated to enhance the environmental and economic sustainability of industrial wastewater treatment. In particular, following a preliminary characterization of secondary effluents, cloth filtration and adsorption were studied, the former by pilot-scale tests, while the latter at laboratory scale. An economic analysis was finally accomplished to verify the full-scale applicability of the most promising technologies. Cloth filtration showed excellent total suspended solids (TSS) removal efficiency (mean 81% removal) but a very limited influence on chemical oxygen demand (COD) (mean 10% removal) due to the prevalence of soluble COD on particulate COD. Adsorption, instead, led to a good COD removal efficiency (50% abatement at powdered activated carbon—PAC—dosage of 400 mg/L). The economic analysis proved that adsorption would be convenient only if a local low-cost (100 €/ton) adsorbent supply chain was established. Ultrafiltration was considered as well as a potential alternative: its huge capital cost (19 M€) could be recovered in a relatively short timeframe (pay-back time of 4.7 years) if the ultrafiltrated effluent could be sold to local industries. [ABSTRACT FROM AUTHOR]

Currently, the pulp and paper industry generates around 50–70 million tons of lignin annually, which is mainly burned for energy recovery. Lignin, being a natural aromatic polymer rich in functional hydroxyl groups, has been drawing the interest of academia and industry for its valorization, especially for the development of polymeric materials. Among the different types of polymers that can be derived from lignin, polyurethanes (PUs) are amid the most important ones, especially due to their wide range of applications. This review encompasses available technologies to isolate lignin from pulping processes, the main approaches to convert solid lignin into a liquid polyol to produce bio-based polyurethanes, the challenges involving its characterization, and the current technology assessment. Despite the fact that PUs derived from bio-based polyols, such as lignin, are important in contributing to the circular economy, the use of isocyanate is a major environmental hot spot. Therefore, the main strategies that have been used to replace isocyanates to produce non-isocyanate polyurethanes (NIPUs) derived from lignin are also discussed. [ABSTRACT FROM AUTHOR]

The emission of off-odors from mechanically recycled plastics severely limits their re-introduction into the market for the production of new objects, for the same use or even for less demanding applications, thus hindering the implementation of an effective circular economy for plastics. The addition of adsorbing agents during the extrusion of polymers represents one of the most promising strategy to reduce the odorous emissions of plastics, due to its characteristics of cost-effectiveness, flexibility and low energy consumption. The novelty of this work lies in the assessment of zeolites as VOC adsorbents during the extrusion of recycled plastics. They appear more suitable than other types of adsorbents, due to their ability to capture and "hold" the adsorbed substances at the high temperatures of the extrusion process. Moreover, the effectiveness of this deodorization strategy was compared with the traditional degassing technique. Two types of mixed polyolefin wastes, coming from completely different collection and recycling processes, were tested: Fil-S (Film-Small), deriving from post-consumer flexible films of small size, and PW (pulper waste), which is the residual plastic waste obtained from the paper recycling process. The melt compounding of the recycled materials with two micrometric zeolites (zeolite 13X and Z310) resulted as more effective in the off-odors removal with respect to degassing. In particular, the highest reduction (−45%) of the Average Odor Intensity (AOI) was measured for both PW/Z310 and Fil-S/13X systems at 4 wt% of the zeolites' amount, compared with the corresponding untreated recyclates. Finally, by combining degassing and melt compounding with zeolites, the best result was obtained for the composite Fil-S/13X, whose Average Odor Intensity resulted as quite close (+22%) to the one of the virgin LDPE. [ABSTRACT FROM AUTHOR]

Circular-economy-based sustainability approaches in construction are gaining wide acceptance due to the volume of waste generation and increasing demand for natural materials. Propelled by the recent timber shortage in Australia and the issues of waste management of cardboard, this study aims to analyse the possibilities of using cardboard as a construction material, based on its initial strength and multiple recycling options. A systematic review of research papers published in the last 40 years has been undertaken using a single keyword search to select the database. The review is presented in terms of the characteristics of the cardboard, dimensional stability, durability, structural strength, design, and analysis of cardboard. Recurring themes are evaluated using a latent Dirichlet allocation approach to identify the factors that ascertain the suitability of cardboard. Analysis reveals that despite certain constraints, such as water absorption and fire resistance, cardboard can be used as a replacement for timber by overcoming such limitations. This observation has benefits for the construction industry and the recycling industry. This study found that cardboard adheres to the circular economy principles, which should inspire policymakers. The paper concludes by highlighting the current circumstances and scientific challenges that impede the usage of cardboard in construction and recommends potential works needed to address these challenges for the benefit of practitioners and researchers. [ABSTRACT FROM AUTHOR]

The application of Life Cycle Assessment in the construction sector can be a very useful tool to reduce the environmental impact generated by the sector. In order to quantify the improvement in environmental terms with the use of artificial lightweight aggregates (LWA) manufactured with waste, in this work, we conducted a comparative evaluation of the life cycle of LWAs for a total of five different scenarios: LWAs obtained in a traditional way, i.e., using exclusively clay in their manufacture (Spanish blond clay, Portuguese red clay and Portuguese blond clay), and LWAs manufactured with four different wastes, with a partial substitution of 2.5% for each of the clays per waste (almond and hazelnut shells, sludge from the purification of paper money, cork dust and coffee grounds). The functional unit was set as the production of 1 kilo of lightweight aggregates and the CML 2000 methodology and the SimaPro software were used. The results obtained in this research allow us to conclude that the addition of organic wastes showed a slightly higher environmental performance than the conventional system, the ALAs manufactured with almond and hazelnut shells being the most environmentally friendly option, with reductions of more than 30% in some cases, followed by the LWAs manufactured with coffee grounds. On the other hand, the addition of paper sewage sludge and cork dust represents minimal environmental optimization. [ABSTRACT FROM AUTHOR]

The optimization of water management in industrial processes is paramount in diminishing or mitigating, as far as possible, the negative externalities generated by its current use within the linear economy model. This research presents methods for the optimization of wastewater from paper mills which are associated with the new sustainability and circular economy model. In this way, the concept of circular economy was applied to the wastewater treatment from a paper mill, with the objective of recovering the resources contained in this type of effluent. The wastewater treatment plant is based on a biological reactor of activated sludge, and treats a flow of 4868 m3·day−1. This study proposes the development and evaluation of indicators of circular economy applied to wastewater from a paper mill, as well as the assessment of the removal performance of color, total suspended solids (TSS), biochemical oxygen demand on the fifth day (BOD5), and chemical oxygen demand (COD), which are higher than 96% in all cases. Per 1 m3 of wastewater from a paper mill, a volume of 0.9 m3 of potentially reusable water and a recovered sludge mass of 0.7 kg are generated; the latter is reused as a mineral filler during the process itself. In light of this, a multivariable statistical analysis was applied to determine the relationship of the operation variables and indicators of circular economy. In this way, wastewater from the paper mill can be regarded as a technological nutrient, which is partially reintroduced into the production process, enabling the recovery of the water and mineral fillers that it contains. [ABSTRACT FROM AUTHOR]

Sustainability in power electronics is a recent research topic. It takes place among current actions to grasp design choices that enable eco-design and circular economy in the domain. This paper shows the results and analysis of a literature review at the intersection of power electronics and sustainability without considering the reliability study of the power electronics systems. The first part explains the scope of the study. The second part shows a bibliometric analysis of the collected publications that underlines a pioneering position at the European level. The third part details the state-of-the-art and its analysis over four investigation topics which are: tools and methods, indicators, circularity and materials. This paper and the work behind are the results of collaboration at the French national level, as part of the workgroup CEPPS (Convertisseurs Electronique de Puissance Plus Soutenables—More Sustainable Power Electronics Converters) supported by the CNRS (Centre National de la Recherche Scientifique—French National Centre for Scientific Research) research group SEEDS (Systèmes d'énergie électrique dans leurs dimensions sociétales—Societal dimensions of electrical energy systems). [ABSTRACT FROM AUTHOR]

In recent years, climate change has begun to put pressure on humanity and affect natural and human systems. The aim of this paper is to provide an improved understanding of the state of the literature on the impacts of climate change that can be addressed through measures related to disaster risk reduction, sustainable agricultural practices, and the circular economy. This review also represents a valuable and fundamental reference for both researchers and practitioners in these fields. A total of 74,703 articles (climate change adaptation, 45,030; disaster risk reduction, 5920; sustainable agricultural practices, 7940; circular economy, 15,813) published between 1990 and 2022 were extracted from the Web of Science Core Collection, and the links between these areas were mapped using VOSviewer. There has been an increase in the amount of published research on these four topics since 2007, indicating the increasing involvement of researchers to address these topics, influenced by the concerns of national and international bodies to address these changes. [ABSTRACT FROM AUTHOR]

Although recycling is considered the core of a circular economy for returning materials to the supply chain, its procedures are poorly understood. Waste recycling is considered a big source of energy saving and a promoter of CO2 recovery. Besides that, it generates jobs and changes markets worldwide. The Brasilian National Policy on SolidWaste (PNRS) recognizesWaste Pickers as the major social agent in the recycling process responsible for putting Brasil among the ten largest paper-recycling countries in the world. This paper presents an analysis of Brasilian recycling chains of paper and plastics and the main challenges for expanding recycling from Municipal solid waste. The research data were obtained from primary and secondary source related to the recycling supply chain of paper and of the following plastics--High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Polypropylene(PP), Polyethylene Terephthalate(PET) and Polystyrene(PS). Enterprises of various sizes, including informal ones and WPs associations/cooperatives, were visited, in the five Brasilian geographic regions, during the years of 2013 and 2014. A nomenclature was defined for the various enterprises that operate in the Brasilian recycling chain. Each node of the plastic and paper recycling chain was described. The main bottleneck observed in these chains is the lack of continuous programs of selective collection with an emphasis on environmental education processes in the 5570 Brasilian municipalities. Several possibilities not only to promote waste recycling but also to increase the productivity of the sorting process are discussed. [ABSTRACT FROM AUTHOR]

The sugarcane industry has assumed an increasingly important role at a global level, with countries such as Brazil and India dominating the field. However, this causes environmental problems, since the industry produces large amounts of waste, such as sugarcane bagasse. This by-product, which is energetically partially recovered in sugar mills and in the pulp and paper industry, can make a significant contribution to the general use of biomass energy, if the usual disadvantages associated with products with low density and a high moisture content are overcome. From this perspective, thermochemical conversion technologies, especially torrefaction, are assumed to be capable of improving the fuel properties of this material, making it more appealing for potential export and use in far-off destinations. In this work, sugarcane samples were acquired, and the process of obtaining bagasse was simulated. Subsequently, the bagasse was dried and heat-treated at 200 and 300 °C to simulate the over-drying and torrefaction process. Afterward, product characterization was performed, including thermogravimetric analysis, elemental analysis, calorimetry, and energy densification. The results showed significant improvements in the energy content, from 18.17 to 33.36 MJ·kg−1 from dried bagasse to torrefied bagasse at 300 °C, showing that despite high mass loss, there is potential for a future value added chain for this waste form, since the increment in energy density could enhance its transportation and use in locations far off the production site. [ABSTRACT FROM AUTHOR]

Food waste is a global challenge, with profound implications for food security, resource utilization, and sustainability. A circular economy represents a promising solution in addressing food waste effectively by keeping food materials and products in use and circulating them within the economy. To provide an overview of the research on food waste and the circular economy model in the past decade, this study examines 1022 documents on food waste and circular the economy to ascertain the state, themes, and knowledge structure of the field. The results showed that the number of publications has increased greatly in the past decade. "Circular economy of food", "bioenergy", "waste valorization", "waste management", "resource recovery", and "environmental assessment" were the major research themes. Earlier studies focused on resource recovery from organic waste and the bioeconomy of bio-products; recent research interests shifted to sustainability and the valorization of agri-food waste. On the other hand, some highly cited documents and productive authors were important in the development of research on food waste and the circular economy. Furthermore, three groups of journals—"food and environmental sciences", "open access", and "environmental sustainability and resource management"—and five clusters of international collaboration—"European Union Group", "advanced economy group", "agricultural economies", "global influencers", and "isolated countries"—were identified. This study provides readers with an overview of the research field of food waste and the circular economy. [ABSTRACT FROM AUTHOR]

This paper examines the implementation of a digital product passport (DPP) using Hyperledger Fabric technology to enhance product lifecycle management within the European Union's circular economy action plan. This study addresses the need for detailed product information on materials, origin, usage, and end-of-life instructions to improve recycling practices and promote sustainable consumption. The approach integrates decentralized identifier (DID) technology for unique product identification using the cheqd.io platform with an enterprise tailored Hyperledger Fabric blockchain network for DPP data management, leveraging their strengths to enhance security and efficiency. This paper details the data model for the DPP, including entities like Product, Manufacturer, Supplier, and Material. Performance tests on the Hyperledger Fabric network demonstrate the system's efficacy, focusing on CRUD operations and scalability. Future work will extend to the development of client applications and more comprehensive performance evaluations considering scalability and network expansion. [ABSTRACT FROM AUTHOR]

In recent decades, there has been growing interest in the thermal conversion of various alternative fuels, such as biomass and waste-derived fuels. One of the technological solutions for the so-called direct co-combustion of fuels is to create mixtures of various fuels, called mixed secondary fuel. However, mixed secondary fuel has different properties compared to primary fuels. Due to this, by properly selecting the types and proportions of mixtures, it is possible to eliminate their potentially negative impact on both combustion technology and the natural environment. In this paper, we decided to prepare mixed secondary fuel by mixing sunflower husk pellets with RDF (refuse-derived fuel) in a ratio of 1:1 and then analyze the combustion process of the produced fuel in fluidized bed conditions. The results obtained on the basis of the presented research indicate that the mixed secondary fuel eliminated the impact of alkali metal compounds on reducing the melting point of ash and, consequently, on the combustion process of the mixed secondary fuel. An additional benefit is the reduction of emissions of harmful compounds into the atmosphere occurring during the combustion of municipal waste and compliance with the concept of the circular economy. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic disrupted global food waste patterns through unanticipated shifts in composition and quantities. This review explores the impacts of COVID-19 on food waste generation and management approaches in the Near East and North Africa (NENA) region during the recovery phase. This paper comprehensively explores food loss and waste in the NENA region. It presents a detailed analysis of pandemic-induced changes in household food waste behaviors, analyses the integration of circular economy principles in recovery strategies and policy implications, and outlines potential avenues for future research in this critical area. The key findings are threefold: First, this study reaffirms that food waste is a critical challenge in NENA, contributing to food insecurity, water scarcity, and environmental issues. Second, the pandemic catalyzed a dichotomy in consumer behaviors—panic buying initially increased waste, while hardship measures later encouraged sustainable waste reduction practices like meal planning and leftover use. Third, adopting a circular economy approach holds potential, yet its implementation remains limited in terms of curbing food waste and promoting sustainability in NENA. Overall, while the pandemic accentuated the urgency of tackling food waste, it also stimulated innovative policy thinking and strategic planning for building more resilient food systems. This paper concludes that leveraging pandemic-driven sustainability mindsets while addressing systemic drivers of waste will be key to mitigating food waste and its impacts moving forward. This paper offers timely insights into the evolving food waste management landscape in NENA, underscoring the need for integrated policies to navigate post-pandemic recovery effectively. [ABSTRACT FROM AUTHOR]

In this paper, we compare the development and possibilities for improvement of waste management in three countries: Slovakia, the Czech Republic, and Poland. Waste management is part of the circular economy. The circular economy is the basis for waste management today. This applies to municipal waste management, too. In this paper, we work with data available in the Eurostat database. We mainly deal with municipal waste in the three chosen countries. The output of this paper is an assessment of indicators such as recycling rates and waste production. The outputs are documented graphically. [ABSTRACT FROM AUTHOR]

Cooperatives address societal challenges embracing values beyond mere profit-oriented production. Considering the ongoing shift to achieve efficient use of resources and increased circularity, cooperatives should be better equipped to incorporate circular economy (CE) and eco-innovation (EI) into their strategies (compared to regular enterprises). This paper reviews the scholarly literature focusing on the application of CE and EI within cooperative studies with the aim to understand the relationships between these topics, identify the existing scholarly communities, and to observe salient research themes. This study refined the method of van den Hoven and Rubalcaba (2016) to conduct a two-step bibliographic review of documents: a thematic analysis of citation data from Scopus (including a manual review of 16 papers) was followed by a bibliometric analysis of 101 documents from Web of Science (using R-Studio's Biblioshiny). Our results identified three intellectual clusters of cooperative studies focusing on the downstream of CE: (1) industrial ecology; (2) recycling; and (3) waste management. Our study also revealed an emerging scholarly field focused on cooperatives and CE, and with little attention to EI. These findings aim at catalyzing the integration of cooperatives more effectively into scholarly discussions, suggesting that environmental sustainability should be recognized as an additional principle of the cooperative identity—providing a wider perspective that enhances interest in the research of these topics and their interconnections. [ABSTRACT FROM AUTHOR]

Roads are currently essential links of communication and economic development. However, these roads are progressively requiring higher quality materials, implying a greater impact on the environment, in order to withstand the high levels of heavy vehicle traffic. Therefore, this research proposes the use of industrial by-products to create bituminous mixtures which are more resistant and durable than traditional ones. The industrial by-products used, are electric arc furnace slag, ladle furnace slag, and cellulose fibers from the papermaking industry. These by-products were physically and chemically characterized to be used to conform with bituminous mixtures. At the same time, bituminous mixtures were conformed with conventional materials, thus being able to compare the physical and mechanical properties of the conformed mixtures through different tests. The results showed how the use of cellulose fibers made it possible to absorb a greater percentage of bitumen, as well as the use of electric arc furnace slag and ladle furnace slag created mixtures, with greater Marshall stability. Therefore, sustainable, durable, resistant, and high waste mixtures were developed in this investigation. [ABSTRACT FROM AUTHOR]

Digital twins offer a promising approach to sustainable value creation by providing specific life cycle data and enabling the monitoring and implementation of circular economy strategies throughout the product's life cycle. By analyzing product, component, and material data, as well as process data, it is possible to create transparency throughout a product's life cycle, build a data-driven product ecosystem, and establish new business and value creation models, from SMEs to large enterprises. This paper identifies application scenarios, their technological readiness level, and the challenges of digital twins for the circular economy in the manufacturing industry based on a systematic literature review. Gaps such as ensuring a continuous flow of information and taking into account the different levels of digitalization of companies are identified. As a main result, a holistic concept for the scoping of a digital twin for the circular economy is presented. One specific use case for end-of-life decision-making is elaborated upon. It is shown that the circular economy can be supported by digital twin data, especially for the optimal decision on end-of-life vehicles. [ABSTRACT FROM AUTHOR]

Food waste is a serious global problem. Efforts to reduce food waste are closely linked to the concepts of circular economy and sustainability. Though food organizations across the world are making efforts to reduce waste in their supply chains, there is currently no theoretical explanation that would underpin the responses of food companies in reducing food waste. Based on interactions with food companies over a nearly 5-year period, we explore the applicability of some well-known and not so well-known organizational theories in the operations management literature to underpin the observed responses of companies in reducing food waste. This paper is one of the first attempts to study food waste from an operations and supply chains point of view, especially from the lens of existing theories in the operations management literature and newer sustainability theories borrowed from other disciplines. Our research findings not only show that existing organizational theories and societal theories can help explain the motivations of firms engaging in food waste reduction, but also call for more research that could help explain some interesting observations that are not apparent when existing theories are used. This paper contributes to the UN's Sustainable Development Goals 1, 2 and 12. [ABSTRACT FROM AUTHOR]

There is a great demand for human–machine interfaces (HMIs) in emerging electronics applications. However, commercially available plastic-based HMIs are primarily rigid, application-specific, and hard to recycle and dispose of due to their non-biodegradability. This results in electronic and plastic waste, potentially damaging the environment by ending up in landfills and water resources. This work presents a green, capacitive pressure-sensitive (CPS), touch sensor-based keypad as a disposable, wireless, and intelligent HMI to mitigate these problems. The CPS touch keypads were fabricated through a facile green fabrication process by direct writing of graphite-on-paper, using readily available materials such as paper and pencils, etc. The interdigitated capacitive (IDC) touch sensors were optimized by analyzing the number of electrode fingers, dimensions, and spacing between the electrode fingers. The CPS touch keypad was customized to wirelessly control a robotic arm's movements based on the touch input. A low-pressure touch allows slow-speed robotic arm movement for precision movements, and a high-pressure touch allows high-speed robotic arm movement to cover the large movements quickly. The green CPS touch keypad, as a disposable wireless HMI, has the potential to enforce a circular economy by mitigating electronic and plastic waste, which supports the vision of a sustainable and green world. [ABSTRACT FROM AUTHOR]

Circularity in cities is key to Earth's sustainable and resource-efficient future. In contrast to the broad framework of circular economy, circularity is a technical concept associated with avoiding disposal and prolonging the useful life of products and materials, and thereby extracting fewer resources. In search of metrics and indicators to measure the impacts of circular processes in cities in real time, the authors reviewed the literature on the circular economy and circularity, in search of evidence-based circularity indicators suitable for cities to use to benchmark the environmental and climate benefits of six waste prevention cascades. This paper reports on a systematic literature review using the PRISMA protocol to screen, evaluate, and review published and grey literature sources. From more than 15,000 papers screened, after application of criteria, fewer than 25 papers were found that presented evidence-based, measurable, and actionable indicators or indicator sets for benchmarking the performance of circular processes in cities. The authors concluded that the practical commitment to evidence-based tracking of circularity (in cities) is weak. Practical progress towards a circular economy and physical and economic circularity will require stakeholders to strengthen and test the very small number of indicators and indicator sets that are relevant and useful for cities and regions to use for measuring their progress towards becoming more circular, and increase evidence-based monitoring for circularity and the circular economy. [ABSTRACT FROM AUTHOR]

Background: The interest in the topic of performance assessment in reverse supply chains (RSC) is increasing, although the body of research is still in its early stages. As this is a developing field, it is crucial to expand discussions on topics that have not yet been thoroughly examined, such as the intrinsic bias of indicators and metrics that may be associated with specific operational, economic, environmental perspectives, etc. Such perspectives should be considered in the decision-making process within the context of reverse logistics (RL) and waste management (WM). The aim of this research was to identify different perspectives employed in the development of proposed models in the literature. Methods: A systematic literature review was conducted to analyze thirty papers from Scopus, Web of Science, and Science Direct databases without time restrictions. Results: The review identified various ways in which authors grouped perspectives, including qualitative and quantitative, sustainability, and operational perspectives, among others. Conclusions: This study revealed several gaps in the field, including limited studies on RSC performance assessment and a lack of studies linking performance assessment to decision-making components. [ABSTRACT FROM AUTHOR]

Coffee silverskin (CSS) is one of the main byproducts of coffee roasting and poses a potential risk to the environment if disposed of incorrectly. Each year in Italy, over 500,000 tonnes of green coffee are imported for roasting followed by consumption or export. This results in over 7500 tonnes of CSS produced each year which is typically disposed of as solid waste. Silverskin contains lignocellulose and can be used as a substitute for other raw materials to produce paper pulp. Both Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) were performed to compare the impact and cost of CSS paper production to conventional paper production using only virgin pulp. It was shown that the addition of CSS reduces the environmental impact of paper production by 10% and greenhouse gas (GHG) emissions by 13% compared to conventional production with no cost increase (0.01% reduction with addition of CSS) for the producer. The results of this case study show that the utilization of CSS for paper production at the national level in Italy represents a suitable example of circular economy (CE). [ABSTRACT FROM AUTHOR]

The implementation of scrap recovery activities has been shown to improve the financial performance of many firms, and this kind of circular economy (CE) is particularly evident in industries with green manufacturing (GM). In this paper, we consider an imperfect multiple-stage production system that manufactures paired products made from mixed materials containing scrap returns, in which the scrap returns are converted from defective products. The feed rates of scrap returns for two products are different, and the product with the higher feed rate is placed in the second order of the process to avoid unlimited accumulation of scrap returns. The proposed problem is formulated as a joint economic order quantity (EOQ) and economic production quantity (EPQ) model aimed at cost minimization. The decision variables of the proposed model include the production run time of two products, order quantity of new material, and the extent of investment in converted equipment. We also prove that the optimal solution exists uniquely and provide an algorithm for the computation of the optimal solution. Finally, a numerical example involving the pulp and paper manufacturing industry is provided to illustrate the solution process, and the results of its sensitivity analysis are also presented to show some managerial implications. [ABSTRACT FROM AUTHOR]

Featured Application: Iron ore tailings are amongst some of the most common and widely available types of mining waste. This paper focus on the geotechnical characterization of these materials in order to promote their potential applications as building materials in more sustainable geotechnical works, namely in embankments, employing the concept of circular economy. The mining industry produces large amounts of tailings which are disposed of in deposits, which neglects their potential value and represents important economic, social and environmental risks. Consequently, implementing circular economy principles using these unconventional geomaterials may decrease the wide-ranging impacts of raw material extraction. This paper presents an experimental characterization of iron ore tailings, which are the most abundant type of mining waste. The characterization includes various aspects of behavior that are relevant to different types of use as a building material, including physical and identification properties, compaction behavior and stress–strain properties under undrained monotonic and cyclic triaxial loading. The tailings tested can be described as low-plasticity silty sand materials with an average solids density of 4.7, a maximum dry unit weight close to 3 g/cm3 and a higher angle of friction and liquefaction resistance than common granular materials. The experimental results highlight the particular features of the behavior of iron ore tailings and emphasize the potentially promising combination of high shear resistance and high density that favors particular geotechnical applications. Overall, the conclusions provide the basis for promoting the use of mining wastes in the construction of sustainable geotechnical works and underpin the advanced analysis of tailings storage facilities' safety founded on an open-minded geotechnical approach. [ABSTRACT FROM AUTHOR]

The integration of recycled polymers into additive manufacturing (AM) processes offers a promising opportunity for advancing sustainability within the manufacturing industry. This review paper summarizes existing research and developments related to the use of recycled materials in AM, focusing on distinct polymers, such as polylactic acid (PLA), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS), among others. Key topics explored include the availability of recycled filaments on the market, challenges associated with material variability and traceability, and efforts toward establishing ethical product standards and sustainability characterization methodologies. Regulatory considerations and standards development by organizations such as ASTM and ISO are discussed, along with recommendations for future advancements in improving the sustainability of filament recycling and achieving net-zero emissions in AM processes. The collective efforts outlined in this paper underscore the potential of recycled polymers in AM to foster a more sustainable and environmentally friendly manufacturing industry. [ABSTRACT FROM AUTHOR]

The global move towards a circular economy, as well as that of achieving the United Nations Sustainable Development Goals (SDGs), has necessitated the search for several sustainable solutions in various sectors. Given this, the provision of sustainable waste management and electricity systems constitute a significant part of the SDGs, and the waste-to-energy (WtE) concept has recently become a key topic given that it can potentially help reduce the dependence on fossil fuels for energy generation, as well as minimizing the need to dispose of waste in landfill. However, to date, the sustainability assessments of WtE generation technologies have been limited in scope concerning the three-dimensional sustainability framework (economic, environmental, and social). Life Cycle Sustainability Assessment (LCSA) has been proposed as a potential approach that could comprehensively address these three pillars of sustainability simultaneously based on life cycle thinking. LCSA, as a holistic method, could also potentially deal with the complexity associated with decision-making by allowing for the consideration of a full range of possible sustainability consequences. LCSA is an analytical tool that integrates the Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and Social Life Cycle Assessment (sLCA) methodologies, which already exist and continue to be developed. Individually, these life-cycle approaches tend to be used to point out particular 'hotspots' in product or service systems, and hence focus on direct impacts in a given sustainability domain, neglecting the indirect ones. LCSA aims for a more holistic sustainability perspective and seeks to address the associated challenge of integrating these three pillars of sustainability into an overall and more comprehensive sustainability assessment. This need for harmonization within the LCSA methodology is a major challenge in its operationalization. In recent years there has been steady progress towards developing and applying LCSA, including for WtE. The aim of this paper is to review the most recent trends and perspectives in developing countries, especially regarding how LCSA could help inform decision-making. The paper also analyses the LCSA literature to set out the theoretical and practical challenges behind integrating the three methods (LCA, LCC, and sLCA). The review was conducted via a search of keywords such as LCSA, waste, and energy in the Web of Science databases, resulting in the selection of 187 publications written in English. Of those, 13 articles operationalized LCSA in specific waste and WtE related case studies. The review provides a review of the application of LCSA for researchers, technological experts, and policymakers through published findings and identifies perspectives on new research. These include uncertainty, subjectivity in weighting, double-counting, the low maturity of sLCA, and the integration of the interconnection between the three dimensions (environmental, economic, and social dimensions) of LCSA results in decision-making. In addition, gaps (such as the integration of the interconnection between the three dimensions) that need to be addressed via further research are highlighted to allow for a better understanding of methodological trade-offs that come from using the LCSA analytical approach to assess the sustainability of WtE generation technologies, especially in developing countries. It is hoped that this study will be a positive contribution to environmental and energy policy decisions in developing countries faced with the dual problems of waste management and electricity supply along with their sustainable development goals. [ABSTRACT FROM AUTHOR]

Straw, the primary agricultural waste, constitutes approximately 20% of the total biomass in the EU. Only a small fraction of the material is applied in various products, e.g., animal bedding, mulch, building, and composite materials, while a significantly larger portion is often burned in the field. This practice, while prohibited for several reasons, including the increased risk of fire and the release of carbon dioxide contributing to global warming, is still prevalent. Given the increasingly evident effects of climate change, EU legislation aims to reduce greenhouse gas emissions as much as possible. One of the strategies includes applying the cascade principle in the circular economy. This principle aims to use the entire raw material, in this case, cereal crops, such that the products with the highest added value, like cellulose fibers from cereal straw, are extracted first. The vast potential for utilizing lignocellulosic agro-waste sustainably arises from its status as the most abundant organic compound on Earth. Its significant presence, renewability, and biodegradability make it a desirable source for producing materials in numerous industries. This study examines the potential of wheat fibers, isolated from the straw of two distinct cultivars (Srpanjka represents an old variety, and Kraljica represents the new variety) primarily for application in technical textiles. The following testing methods were applied: determination of wheat fibers and residues yield, fibers tensile properties, length, moisture content/regain, density, morphology, and Fourier transform infrared (FTIR) spectroscopy. The yield of isolated fibers relies on the wheat variety and the climatic conditions affecting plant growth, resulting in fiber yields from 10.91% to 15.34%. Fourier transform infrared (FTIR) analysis indicates reduced peak intensity, which is related to hemicellulose and lignin content, suggesting their improved deposition following the process of chemical maceration. Wheat fiber quality was found to be comparable to cotton fibers regarding its density. However, they showed a significant difference in higher moisture regain (9.72–11.40%). The vast majority of the scientific papers related to wheat fibers did not indicate the length of the individual fibers obtained by chemical maceration nor their strength. Therefore, this paper indicated that both varieties demonstrated sufficient fiber tenacity (greater than 10 cN/tex) and fiber length (2–3 cm), stressing the spinning potential of these fibers into yarns and extending their use to the apparel industry. Moreover, our research underscores the feasibility of adhering to the zero-waste principle. A high percentage of solid waste remaining after fiber extraction (25.3–39.5%) was successfully used for biofuel production, thus closing the loop in the circular economy. [ABSTRACT FROM AUTHOR]

Background: Wastewater treatment plants (WWTPs) are crucial in the scope of European Commission circular economy implementation. However, bioaerosol production may be a hazard for occupational and public health. A scoping review regarding microbial contamination exposure assessment in WWTPs was performed. Methods: This study was performed through PRISMA methodology in PubMed, Scopus and Web of Science. Results: 28 papers were selected for data extraction. The WWTPs' most common sampled sites are the aeration tank (42.86%), sludge dewatering basin (21.43%) and grit chamber. Air sampling is the preferred sampling technique and culture-based methods were the most frequently employed assays. Staphylococcus sp. (21.43%), Bacillus sp. (7.14%), Clostridium sp. (3.57%), Escherichia sp. (7.14%) and Legionella sp. (3.57%) were the most isolated bacteria and Aspergillus sp. (17.86%), Cladosporium sp. (10.71%) and Alternaria sp. (10.71%) dominated the fungal presence. Conclusions: This study allowed the identification of the following needs: (a) common protocol from the field (sampling campaign) to the lab (assays to employ); (b) standardized contextual information to be retrieved allowing a proper risk control and management; (c) the selection of the most suitable microbial targets to serve as indicators of harmful microbial exposure. Filling these gaps with further studies will help to provide robust science to policy makers and stakeholders. [ABSTRACT FROM AUTHOR]

This paper presents the initial prototypes of solutions designed using plastic caps, seeking acoustic applications for both airborne sound insulation and the acoustic conditioning of rooms. Plastic caps are a waste product from the packaging sector and they constitute a major waste problem, given that, if they are not attached to the packaging, they get lost during the recycling cycle and end up in landfill. Finding an application for this waste that can provide acoustic improvements is a sustainable alternative. This paper shows the results of airborne sound insulation measurements obtained in a scaled transmission chamber and sound absorption measurements obtained in a scaled reverberation chamber for different combinations of single and double plastic caps and combinations with thin sheets of sustainable materials, such as jute weaving, textile waste, hemp felt and cork board. Tests have shown that obtaining sound reduction index values of up to 20 dB is possible with plastic cap configurations, or even up to 30 dB is possible at some frequencies with combinations of caps and certain eco-materials. With regard to the sound absorption coefficient tests, close to unity absorption values have been achieved with the appropriate configuration at frequencies that can also be selected. The results indicate that these panels can be eco-solutions for airborne sound insulation as lightweight elements, or they can be used for the conditioning of rooms, tailoring the sound absorption maximums to the desired frequencies. [ABSTRACT FROM AUTHOR]

Municipal sewage sludge (MSS) is an inevitable byproduct of wastewater treatment, with increasing amounts year by year worldwide. The development of environmentally and economically acceptable methods for the sustainable management of MSS is a major environmental challenge. Nowadays, sludge management practices, besides the commonly used stabilization methods, focus attention on alternative sludge-disposal pathways, which encompass enhanced energy and valuable-resource recovery. This review presents the recent advances in the recovery of selected value-added products from sludge. Because of the high nitrogen and phosphorus concentrations, waste MSS can be a nutrient source (e.g., struvite). This paper discusses the conditions of and advances in the technology of struvite recovery. As in the extracellular polymeric substances (EPSs) of biological sludge, alginate-like exopolymers (ALEs) are present in MSS systems that treat municipal wastewater. The yields, dynamics in content, and characterization of ALEs and their possible applications were analyzed. MSS is an important source of humic substances. Their occurrence, characterization, and yields in various types of MSS (e.g., untreated, composted, and digested sludge) and main methods of application are presented. The important aspects and trends of MSS pyrolysis, including the thermochemical conversion to biochar, are discussed in this review. The characterization of biochar derived from MSS and the assessment of the environmental risks are also covered. This paper explores the potential use of biochar derived from MSS in various applications, including soil amendment, carbon sequestration, and environmental remediation. [ABSTRACT FROM AUTHOR]

Lignin, a complex and heterogeneous biopolymer derived from wood, holds immense potential as a sustainable feedstock for various industrial applications. Kraft pulping, a widely employed process in the paper industry, generates black liquor containing lignin along with other organic and inorganic compounds. The precipitation of lignin from black liquor offers an opportunity for valorization, contributing to the circular economy and reducing the environmental impact. Although the precipitation process of softwood lignin is extensively documented and outlined in the existing literature, the identical process originating from hardwood-derived black liquor poses challenges attributed to the distinct composition of hardwood. This study systematically investigates the individual and combined influences of temperature and pH on the precipitation of hardwood lignin from kraft black liquor, utilizing a factorial design to evaluate lignin functional characteristics. The characterization of the precipitated lignin was performed using various analytical techniques, mainly NIR, elemental composition, UV-VIS, and calorimetry. The results reveal remarkable interactions between temperature and pH, indicating their synergistic effects on lignin precipitation. The optimal conditions for hardwood lignin precipitation were identified and successfully upscaled during piloting experiments conducted under industrial conditions. This research provides valuable insights into the fundamental factors governing hardwood lignin precipitation from kraft black liquor and offers a basis for the development of efficient and sustainable lignin recovery processes in the pulp and paper industry. [ABSTRACT FROM AUTHOR]