Life Cycle Assessment Results Research Articles

Shifting units, shifting views: how product mass and protein content influence environmental impact of Icelandic lamb

Abstract Purpose Lamb meat is a crucial protein source in Icelanders’ diets. Extensive grazing lands, locally grown hay feed, and traditional farming methods are often used as arguments for Icelandic lamb meat’s environmental friendliness. However, no life cycle assessment (LCA) study exists to corroborate these arguments. This study conducts a national-level LCA to evaluate the environmental performance of lamb meat based on two functional units to identify key hotspot processes in its production. Method This study conducts a cradle-to-farm gate LCA at the national level for two functional units: 1 kg of edible lamb meat (ELM) and 100 g of ELM protein produced in Iceland in 2019. The multifunctionality between wool and meat is handled using mass allocation. The environmental impacts were estimated using the ReCiPe 2016 v1.1 mid-point (H) impact assessment method, emphasizing selected environmental categories: global warming, fossil resource scarcity, land use, and terrestrial ecotoxicity. In addition, the study conducts a scenario-based variability analysis by taking minimum and maximum values of inventory data to estimate the possible range of environmental impacts. Lastly, an overall uncertainty analysis and a global sensitivity analysis of the key hotspot process shed light on the variability and sensitivity of the LCA results. Result and discussion For the 18 ReCiPe impact categories, animal and feed (hay) production are the hotspot processes, followed by feed (grazing) as a hotspot for land use. The global warming impact for 1 kg of ELM ranges 41–53 kg CO2 equivalent, and for 100 g of protein, 19–29 kg CO2 equivalent. Fossil resource scarcity impact for 1 kg of ELM impact ranges 2.5–3.6 kg oil equivalent, and for 100 g protein, 1–2 kg oil equivalent. Terrestrial ecotoxicity impacts for 1 kg of ELM range 46–69 kg 1,4-DCB, and for 100 g protein, 21–37 kg 1,4-DCB. Lastly, land use impacts for 1 kg of ELM range 562–2448 m2a crop equivalent, and for 100 g protein, 261–1324 m2a crop equivalent. Conclusion With its traditional farming practices, Icelandic lamb meat production is close to an extensive farming system, which is in line with its higher global warming impact per kg ELM. Additionally, due to low hay yield and high fertilization rate, the impact on other impact categories is still higher compared to an extensive system. This perspective shifts when analyzed per 100 g of protein, where it performs close to the global average.

Life cycle environmental impact assessment of steel structures using building information modeling

Building Information Modelling (BIM) and Life Cycle Assessment (LCA) are fundamental components within building projects. LCA is critical in building projects’ sustainability. The integration of BIM has the potential to enhance the LCA process, leading to better outcomes. Design for Deconstruction (DfD) study on minimizing, reusing, and recycling of building materials is closely linked. This study aims to evaluate and compare the findings obtained from the E-tool LCD and Tally LCA add-in tools; both used as BIM-based LCA tools. This paper outlines the overarching approach to implementing a process-based LCA for a steel building, explicitly emphasising the many processes the building undergoes during its life cycle. The LCA add-in tools, namely e-tool LCD and Tally, have been chosen to discern the disparities in the LCA outcomes resulting from using Environmental Product Declaration (EPD databases that vary across various regions. The input data, system boundaries, and LCA scope remained consistent throughout the LCA procedures. Global Warming Potential values obtained from the manufacturing module developed by e-tool LCD were included in a case study. A case study of steel structure is used to implement the LCA add-in tools. The discussion also addressed the challenges of enhancing interoperability in contemporary BIM-based LCA procedures. The study revealed that using EPD databases with regional variations notably impacts LCA outcomes. Consequently, the compatibility assessment in BIM-based LCA procedures yielded value innovation, efficiency, and distinctiveness.Furthermore, it was determined that BIM-LCA procedures resulted in notable distinctions compared to conventional LCA methods. These distinctions included enhanced convenience of application, increased efficiency in terms of time and resources, and higher levels of accuracy.

Sustainable High-Performance Structural Materials from Micro/nanostructured Corn Stover.

Corn stover, as an abundant agricultural residue, has not been well reutilized due to the lack of efficient utilization methods. Based on micro/nanoscale structure design of corn stover, we report an environmentally friendly strategy to prepare micro/nanostructured corn stover-based building blocks. Then, through the directed deformation assembly approach, a high value-added corn stover structural material (CSSM) that with higher strength and more excellent thermal stability than most widely used plastics and wood-plastic composites can be prepared. The entire production process is green and economical, and the life cycle assessment (LCA) results indicate that it is a low-carbon emission, sustainable material. Moreover, CSSM can be composed with nanoscale building blocks to achieve multifunctionality. For example, by incorporating carbon nanotubes, we prepare a corn stover structural material with Joule-heating effects for indoor thermal management. This broadens the range of applications for corn stover-based structural materials.

Economic and Environmental Impact Analysis of Innovative Peeling Methods in the Tomato Processing Industry

Peeling is a key step in the industrial production of canned peeled tomatoes, vital for optimizing efficiency, yield, product quality, waste reduction, and environmental impact. This study presents a comparative assessment of the economic and environmental impacts of adopting innovative peeling technologies, including infrared (IR), ohmic heating-assisted lye (OH-lye), and ultrasound-assisted lye (US-lye) peeling, relative to conventional steam and lye peeling methods. Focusing on a medium-sized Italian tomato processor, the impacts of these methods on productivity, water and energy consumption, wastewater generation, and environmental footprint using Life Cycle Assessment (LCA) methodology, were evaluated. Findings indicated that adopting IR, OH-lye, and US-lye methods enhanced peelability (ease of peeling > 4.5) and increased production capacity by 2.6–9.2%, while reducing solid waste by 16–52% compared to conventional steam and lye methods. LCA results showed IR as the most environmentally favorable method, followed by steam, OH-lye, and US-lye, with conventional lye peeling being the least sustainable. OH-lye and IR methods also significantly reduce water and energy use, while US-lye shows higher demands in these areas. Additionally, OH-lye and IR methods require little or no NaOH, minimizing chemical consumption and wastewater production, which offers notable environmental and cost advantages. Overall, this preliminary study underscores economic and environmental potential for novel peeling technologies, encouraging industry consideration for adoption.

Environmental impact assessment of manufacturing seawater desalination technology using life cycle assessment

Abstract The seawater desalination technology, named WEFO (Water with Electrolysis, Filtration, and Ozonation), holds significant potential for addressing clean water scarcity in coastal areas. This study employs Life Cycle Assessment (LCA) to evaluate the environmental impact of producing the WEFO device. The LCA results indicate notable environmental impacts, mostly attributable to using stainless steel and aluminum alloy. Stainless steel contributes 72.81% to abiotic depletion, 85.54% to acidification, 47.64% to eutrophication, 79.87% to freshwater ecotoxicity, 81.05% to terrestrial ecotoxicity, and 81.40% to photochemical oxidation. Meanwhile, aluminum alloy is responsible for 57.48% of global warming and 64.10% of ozone layer depletion. The manufacturing process of these materials emits pollutants that damage air and water quality and contributes to climate change and ecosystem disturbance. To mitigate these impacts, it is advisable to decrease the utilization of materials with significant environmental consequences in components such as wheel plates, faucets, and frames, replacing them with more environmentally friendly alternatives. Implementing these alternatives is expected to make WEFO technology more sustainable and provide an environmentally friendly solution to clean water scarcity in coastal areas while preserving human and ecosystem health.

Mussel byssus cuticle-inspired low-carbon footprint soybean meal adhesives with high-strength and anti-mildew performance

Bio-based adhesives, because of their prominent non-toxic and sustainable properties, have attracted great attention to replace conventional formaldehyde-based adhesives. However, most bio-adhesives have poor bonding properties and antimildew stability, which seriously hinder the practical application. Herein, a coordination structure-enhancement method for the preparation of bio-based adhesives was developed that avoids the use of large amounts of crosslinking agents and produces new bio-based adhesives with good properties. The wet bonding strength of this adhesive manufactured by introducing mussel byssus cuticle-inspired complexes (FeTA) and glycerol triglycidyl ether (GTE) is as high as 1.05 MPa, far exceeding that of pure soybean meal adhesive. In addition, the resulting adhesives showed superior thermal stability and mildew resistance. Life cycle assessment results indicate that the novel adhesive production process has a minimal environmental impact. Overall, this environmentally friendly bio-based adhesive demonstrated in this study could be a promising substitute for petrochemical-based formaldehyde adhesives.

Life cycle analysis of a solar photovoltaic system in a Philippine university

Abstract Renewable energy sources have been growing in popularity because of the Republic Act 9513, also known as the Renewable Energy Act 2008. With these, various universities in the Philippines have already installed solar photovoltaic (PV) systems. However, details such as carbon emissions reduction and the efficiency of PV systems in Philippine universities still need to be included as baseline data for policy formulation and sustainability. This study aims to evaluate the solar PVs installed at Saint Louis University as part of its climate change advocacy. The environmental Life Cycle Assessment (LCA) approach was conducted through the OpenLCA software with the Ecoinvent database. Results showed that the PV panels installed in the university are economically and environmentally beneficial, wherein the installed panels’ break-even point and cost-benefit ratio are 7 years and 4.5, respectively. Through the cradle-to-grave analysis from manufacturing, transportation, installation, operation, and recycling, the solar PV system yielded an annual emission savings of 278,369 kg of CO2 equivalent. Moreover, the GHG emission payback period was only 2.22 years, with a 93% GHG reduction from utilizing solar PV systems instead of coal-fired power plants. With the summarized results of LCA, this paper hopes to contribute to the solar energy data on Energy Payback Time (EPBT) and GHG emission rates.

Environmental Impact of Poultry Manure Gasification Technology for Energy and Ash Valorization

Thermochemical technologies offer potential solutions for energy recovery and mitigating the environmental impacts of biomass waste. Poultry manure (PM), a nutrient-rich biomass but also a potentially problematic biomass waste, presents an opportunity for recovery and recycling. This study compares the environmental performance of a real-scale novel gasification technology called Chimera (designed and developed through an EU LIFE program) in locally treating PM with anaerobic digestion (AD) and incineration. Using life cycle assessment (LCA), the potential environmental impacts of the technologies were assessed using the Environmental Footprint (EF) 3.0 midpoint life cycle impact assessment method. We performed an attributional LCA with substitution. The selected functional unit (FU) is the treatment of one tonne (1000 kg) PM at 40% dry matter in the Netherlands in 2021 for 20 years. The LCA results of the three technologies compared showed that no single technology outperformed the other across all the impact categories. Climate change scores for the various technologies were −383 (incineration), −206 (Chimera), and −161 (anaerobic digestion) kg CO2 eq./FU. The results were influenced mainly by the potential utilization of the substituted heat and electricity. This study expands the existing literature on environmental sustainability assessments of PM treatment technologies. It underscores the prospects for these technologies to promote circularity while also indicating the bottlenecks for the potential environmental impacts and highlighting the most sensitive aspects that can influence the environmental performance of these technologies.

Accounting for decarbonization impacts across the full life cycle of alternative concrete materials: A case-study for graphene-amended cementitious composites

Concrete's extensive use worldwide comes with significant environmental cost, contributing to 8% of annual global carbon emissions. This study investigates the use of life cycle assessment (LCA) and technoeconomic assessment (TEA) as tools to quantify anticipated reductions in global warming potential (GWP) arising from use of novel concrete mixtures or innovative production techniques, with specific focus on a case study related to graphene nanoplatelets (GNPs) as functional fillers. LCA and TEA results are reported for several choices of functional unit (FU) and system boundaries (SB). This approach illustrates how various LCA and TEA framings are differently useful to articulate how changes in technical performance properties such as mechanical strength and durability influence overall life-cycle environmental impacts. Framing 1 make use of a nominal volume-based FU (1 m3) and cradle-to-gate SB. Under this framing, addition of GNPs to the base mix seems to increase GWP and production cost. Framing 2 makes use of a strength-normalized FU and cradle-to-gate SB. Under this framing, life-cycle GWP and production cost for the GNP-amended mortars are decreased relative to the control, due to the appreciable increase in mechanical strength of the GNP-amended mortars. Finally, Framing 3 makes use of the nominal volume-based FU (1 m3) and cradle-to-grave SB. Under this framing, GWP and production cost for the GNP-amended mortars again seem to decrease, due to improved durability which gives rise to longer estimated service life and reduced maintenance. This study illustrates that use of GNPs as functional filler is a seemingly promising strategy for decarbonizing concrete. More broadly, it is concluded that LCAs and TEAs of novel concretes should be framed in a way that articulates how changes in mechanical strength and/or durability properties contribute to changes in environmental impacts over all stages of the concrete life-cycle (i.e., cradle-to-grave). Such framing will help ensure that results that are meaningful to support decision-making in the area of sustainable construction materials.

Interpreting environmental impacts of wooden windows based on existing EPDs: An application in Italy

To meet climate targets, it is necessary to adopt robust and recognized methods, such as life cycle assessment (LCA), to evaluate emissions, particularly from building materials. As shown in the literature, embodied impacts have become as significant as operational impacts. The embodied impacts of a specific product are given in a transparent and quantitative manner in environmental product declarations (EPDs), based on LCA results. Windows play a crucial role in the energy performance of buildings. In fact, they typically account for 10–25 % of the exposed area of a building, resulting in more than 60 % of its total energy loss. In Italy, wooden windows make up 28 % of the window market and are the cheapest option for mild climates over a timeline of 60 years. However, an important element is still missing: a simplified interpretation of EPD results to enable straightforward, balanced comparisons of the environmental performance between alternatives. In this context, an analysis based EPDs of wooden windows is proposed, with a focus on production and use stages, for the six Italian climate zones. The three main steps of the study are: 1) evaluation of the influence of window properties on the embedded impacts; 2) assessment of maintenance scenarios; and 3) estimation of operational impacts regarding window properties and exposed climate. The results suggest that the influence of thermal transmittance, wood type and exposed climate is higher for cold climates due to better performing production materials and more frequent maintenance during service life.

Life Cycle Assessment of an Avocado: Grown in South Africa-Enjoyed in Europe.

Food production is known to have significant environmental impacts, with the main contributors residing in the farming and transportation life cycle phases. Of the various food products transported around the world, avocados have increasingly gained attention as a high-commodity superfood. Avocados require specific climatic and agricultural conditions for farming, with the most fertile land and conditions located outside Europe. Consequently, most avocados consumed in Europe are imported over vast geographical distances, with little information available to quantify the environmental impacts of this imported superfood. This paper aims to present the most detailed life cycle assessment results of an avocado cultivated, grown and harvested in the Limpopo Province of South Africa and exported to the European market for sale and consumption. A life cycle assessment was developed for the farming, harvesting, handling, packaging, ripening, transportation, and carbon sequestration potential of the avocado, and it was used to conduct a holistic life cycle assessment. Input data was obtained through an 18-month data collection campaign across the relevant stakeholders. A baseline 'business-as-usual' scenario is focused on throughout this study, and scope for optimisation is identified for each life cycle phase where applicable, accompanied by uncertainty analyses. Results show a total carbon input of 904.85 kg CO2e/tonne. Mitigating this, 521.88 kg CO2e/tonne is offset, resulting in a net carbon footprint of 382.97 kg CO2e/tonne with uncertainty ranges of -23.22 to +58.69 kg CO2e/tonne, normalised to 57.45 g CO2e/avocado grown in South Africa and sold in Europe. The environmental impacts of the avocado industry under consideration are largely mitigated by the "nature first" philosophy of the farming and logistics enterprises, which have made significant investments in reducing emissions. Sensitivity analyses indicate that implementing large-scale renewable energy, using alternative packaging instead of cardboard, and selling avocados unripened could further enable the farming enterprise to achieve Net Zero objectives. These measures could reduce baseline emissions from 382.97 kg CO2e/tonne to a theoretical -68.54 kg CO2e/tonne, representing a 117.9% decrease. Although this study does not quantify climate change impacts, qualitative analyses suggest that climate change will have a net negative effect on the avocado industry in South Africa. These regions, typically located in micro-climates, are projected to become wetter and warmer, adversely affecting crop phenology, pest control, road conditions, management complexity, farmer livelihoods, and food security. The study recommends large-scale implementation of the optimisation strategies identified to achieve Net Zero objectives and the development of proactive climate change mitigation strategies to enhance the resilience of avocado supply chains to future stressors. These insights are crucial for policymakers, industry stakeholders, and consumers aiming to promote sustainability in the avocado market.

Comparative Study of Life-Cycle Environmental and Cost Performance of Aluminium Alloy–Concrete Composite Columns

As is widely known, the construction industry is one of the sectors with a large contribution to global carbon emissions. Despite numerous efforts in the construction industry to develop low-carbon materials, there is a limited number of studies quantifying and presenting the overall environmental impact when these materials are applied in a construction project as structural members. To address this gap, this study focuses on assessing the life-cycle performance of novel structural aluminium alloy–concrete composite columns. In this paper, the environmental impacts and economic aspects of a concrete-filled aluminium alloy tubular (CFAT) column and a concrete-filled double-skin aluminium alloy tubular (CFDSAT) column were assessed using life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) approaches, respectively. The cradle-to-grave system boundary is considered for these analyses to cover the entire life-cycle. A concrete-filled steel tubular (CFST) column is also assessed for reference. All columns are designed to have the same load-carrying capacity and, thus, are compared on a level-playing basis. A comparison is also made of the self-weight of these columns. In particular, the self-weight of the CFST column is reduced by around 17% when the steel tube is replaced by an aluminium alloy tube, and decreased by 47% when the double-skin technique is adopted in CFDSAT columns. The LCA results indicate that the CO2 emission of CFST and CFAT is almost the same, which is 21% less than the CFDSAT columns due to the use of high aluminium in the latter. The LCCA results show that the total life-cycle cost of CFAT and CFDSAT columns is around 29% and 14% lower, respectively, than that of the CFST column. Finally, a sensitivity analysis was carried out to evaluate the effects of data and assumptions on the life-cycle performance of the examined columns.

Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam

Additive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.

Application of intuitionistic fuzzy set in social life cycle impact assessment

Abstract Purpose Intuitionistic fuzzy set (IFS) has been found promising for handling ambiguity forms of uncertainty in social data. This paper undertakes an application of an intuitionistic fuzzy set in the social life cycle impact assessment (S-LCIA) of a public building project. This work proposes to combine an intuitionistic fuzzy set (IFS) with multi-attribute decision-making in converting qualitative data into quantitative social impacts of the building project. This research utilises IFS to accommodate and handle experts’ imprecise cognitions in S-LCIA to facilitate the identification and prioritisation of the most pressing indicators accompanying social impacts in a project. Methods Data were collected using questionnaire(s), structured interviews, and through targeted focus group sessions. Intuitionistic fuzzy set (IFS) approach was used to model the obtained data from structured interviews. Using IFS, this research also accounts for missing or ambiguous data that emerged during the data elicitation process. In combining IFS with multi-attribute decision-making techniques, the social impacts of selected stakeholders were evaluated using fuzzy set and IFS approaches. Sensitivity analysis was then used to test the robustness of the results and ranking was conducted based on each social stakeholder subcategory. Results and discussion Results revealed that approximately 23% of missing datapoints in the public case study building were incorporated in the S-LCIA using IFS. The issues of highest priority in each of the considered subcategory in the public case study building project according to IFS are (i) consumer privacy by adopting more functional planning (0.27), (ii) public commitment to sustainability (0.33), and (iii) education provided in the local community by having an indigenous botanical element for children (0.39), respectively. Conversely, the FS technique inferred that the issue of highest priority in the consumer stakeholder is the feedback mechanism (0.26). The overall degree of correlation between the IFS and FS is only 0.234, revealing that IFS provides a different perspective from conventional FS when used in modelling social data. Conclusion The IFS method provides an objective and systematic approach for dealing with a heterogeneous scope of imprecise and inexact social data in achieving holistic social life cycle assessment results. Furthermore, expansive stakeholder involvement would rely on a robust approach for improving social well-being in public buildings, thereby leaving no one behind in accomplishing a sustainable world.

Life cycle assessment (LCA) and economic analysis of two-stage anaerobic process of co-digesting palm oil mill effluent (POME) with concentrated latex wastewater (CLW) for biogas production

This study outlines the results of a process-based life cycle assessment (LCA) of the environmental performance of biogas production from co-digestion of palm oil mill effluent (POME) and concentrated latex wastewater (CLW) in the two-stage anaerobic digestion (AD) process. Biogas is utilized global across several sectors, including electricity generation, heating, and transportation. The Open LCA 2.0.2 software was used to evaluate the LCA at the midpoint level by using 18 different impact categories. This study reveals the three main contributions of the AD process, which were global warming (8.65 × 102 kg CO2eq), water consumption (5.32 m3), and land use change (3.39 × 102 m2 a crop eq), this result corresponded with the previous study in Malaysia that examined biogas production from the AD of POME In addition, alternative scenarios, in which a single substrate, have been established to quantify the impacts of potential improvements of biogas production to compare with base scenario of co-digestion. The results show that the environmental impacts of the base scenario released were lower than those of the single POME substrate of alternative scenario 1 in most impact categories. Furthermore, economic analysis is a crucial factor in the practical implementation of the AD process. Linking LCA with economic analysis offers a comprehensive perspective on sustainability, balancing environmental impacts with financial performance to optimize the potential of the AD co-digestion process. This is the first study to apply LCA and economic analysis to this specific co-digestion process in a two-stage AD system. The economic analysis of the two-stage AD of co-digesting POME and CLW was 1200 m3/d production of wastewater (70 % of POME and 30 % of CLW) based on the factories' data. The result indicates net present value, internal rate of return, and payback period of 515,813.94 USD, 9.13 %, and 8.87 years, respectively. This work proposed the potential approach for implementing the two-stage AD co-digestion of POME and CLW while concurrently producing valuable bioenergy carriers.

Potential of polyethylene terephthalate (PET) in a circular economy from a life cycle assessment perspective - a case study for anaesthesia and surgical instrument packaging waste in Australia

Plastics are a versatile material group with many applications in the healthcare sector. Clinicians, particularly in the operating rooms, have become increasingly dependent on single-use instruments and consumables typically packaged in Polyethylene Terephthalate (PET) resulting in significant amounts of PET waste. In this study, a life cycle assessment (LCA) methodology based on ISO 14040/44 is conducted to assess the environmental impacts of existing and potential future end-of-life options for PET anaesthesia and surgical instrument packaging waste in an Australian hospital context. The results show the reduction potential of environmental impacts by recycling of PET waste via direct collection or in Materials Recovery Facility (MRF) in Australia, Indonesia and New Zealand. When replacing end-of-life options such as landfill or incineration with recycling, a reduction of 88% of total Climate Change (CC) impact can be seen. Furthermore, there is a reduction in environmental impacts across other impact categories through this change. Even if the recyclate quality (up to 30%) was reduced, there is a significant reduction in the environmental impacts. The transition of end-of-life options to recycling offers the potential for reduction of emissions and enables a circular economy for plastics. Furthermore, based on the results of LCA, opportunities and challenges of circular economy pathways in health industry are identified and discussed in this study.

Life cycle assessment of liquid biofuels: What does the scientific literature tell us? A statistical environmental review on climate change

More than 580 peer-reviewed articles dealing with life cycle assessment (LCA) of biofuels, published from 2012 to 2020, were identified in the scientific literature. Articles without a clear and complete LCA hypothesis were discarded. This resulted into 172 useable articles, providing 566 carbon footprints. LCA of biofuels is a topic that has attracted increasing interest in recent times, with an average production of 20 papers per year on the subject. The objectives addressed range from installation optimisation and the assessment of new types of biomass to comparison of pathways and the impact of methodological choices in LCA. The analysis of published carbon footprints reveals a hierarchy in terms of the carbon footprint of diesel, gasoline, and jet fuel substitutes. The type of feedstock appears to be a determinant. Data collected from the literature highlight that biofuels’ carbon footprint varies greatly. However, the climate change mitigation potential of some pathways can be clearly confirmed. Methodological choices adopted by LCA practitioners remain an important source of differences in LCA results, as the allocation choices for co-products or the inclusion of land use change can lead to a wide range of results. The carbon neutrality principle also has the potential to influence LCA results, as described in the statistical analysis. Through an extensive literature review and a statistical analysis using econometric methods, this work provides an overview and analysis of the variability of the environmental impacts of biofuels in terms of greenhouse gas (GHG) to help shape stakeholder decision-making.

Synergistic environmental benefits from copper slag recycling in China: Pollutant mitigation and carbon reduction

In response to the dual challenges of climate change and environmental degradation, China is prioritizing efforts to manage both pollution and carbon emissions. Given China's leadership in global copper smelting, recycling substantial amounts of copper slag is considered a key strategy for environmental improvement. This study applies life cycle assessment (LCA) to evaluate the environmental benefits of three copper slag recycling strategies. Building on the LCA results, we introduced a synergistic reduction index system that assesses the combined effects of pollution mitigation and carbon reduction. Findings indicate that utilizing recycled copper slag in building materials not only significantly reduces local industry emissions but also demonstrates substantial synergistic effects. This strategy optimally reduces both air pollution and carbon emissions, largely due to the substitution of high-pollution materials with recycled copper slag. Based on these insights, we propose targeted recycling strategies tailored to regional needs and capacities, thereby offering practical suggestions for the sustainable management of copper slag.

Investigating interface adhesion of PLA-coated cellulose paper straws: Degradation, plant growth effects, and life cycle assessment

Although bioplastics and paper straws have been introduced as alternatives to single-use plastic straws, their potential environmental, economic, and social impacts have not been analyzed. This study addresses this gap by designing a polylactic acid layer interface adhesion on cellulose paper-based (PLA-P) composite straws by a dip molding process. This process is simple, efficient, and scalable for massive production. Optimizing key manufacturing parameters, including ice bath ultrasonic, overlapping paper strips (2 strips), winding angle (60°), soaking time (5 min), and drying temperature (50 °C), were systematically evaluated to improve straw quality and manufacturing efficiency. PLA chains were found to deposit onto the cellulose network through intermolecular interactions to form a consistent "sandwich" structure, which can improve adhesion, water resistance, and mechanical properties. Interestingly, PLA-P straws effectively decomposed in soil and compost environments, with a 35–40 % degradation rate within 4 months. Besides, PLA-P straw residues affected seed germination and plant growth, but no significant toxic effects were detected. Further, microplastics were observed in soil and plant tissues (roots, stems, and leaves), and their possible diffusion mechanisms were explored. The results of a comprehensive life cycle assessment (LCA) and cost analysis showed that the process improvements reduced the ecological footprint of PLA-P straws and showed good prospects for commercial application. The study's findings contribute to the understanding of bioplastics and paper straws in effectively reducing environmental impact and fostering sustainable development.

Pre-treated municipal solid waste bottom ash as alkali-activated mortar precursor

Pre-treated incinerator bottom ash was used as a precursor of alkali-activated mortars. Control mortars were produced using coal fly ash. Different combinations of alkaline activator were tested (sodium oxide/binder ratio (4%, 6%, 8%, 10% and 15%) and silicon dioxide/sodium oxide ratio (0, 0.5, 1.0, 1.5 and 2.0)) and the influence of these on the mortar's mechanical performance was evaluated. The mortars were tested in both fresh (for density and workability) and hardened states (for dry density, compressive and flexural strengths and modulus of elasticity) after 7, 28, 91 and 182 days. The first stage of work was precursor pre-treatment in a sodium hydroxide solution to prevent the expansion of fresh specimens due to the reaction of aluminium with the alkaline activator. The pre-treatment was effective in preventing excessive hydrogen gas generation during setting, leading to dimensional stability and improved strength. Different optimum sodium oxide contents were observed after 28 days (i.e. 15% for fly ash specimens and 8% for bottom ash specimens). The results of a simplified life-cycle assessment showed that such mixes exhibited lower overall carbon dioxide emissions when compared with cement-based counterparts. However, this trend was reversed with increasing contents of sodium hydroxide and sodium silicate.