Life Cycle Assessment Studies Research Articles

Balancing Patient Needs With Environmental Impacts for Best Practices in General Anesthesia: Narrative Review and Clinical Perspective.

Discussions of the environmental impacts of general anesthetics have focused on greenhouse gas (GHG) emissions from inhaled agents, with those of total intravenous anesthesia (TIVA) recently coming to the forefront. Clinical experts are calling for the expansion of research toward life cycle assessment (LCA) to comprehensively study the impact of general anesthetics. We provide an overview of proposed environmental risks, including direct GHG emissions from inhaled anesthetics and non-GHG impacts and indirect GHG emissions from propofol. A practical description of LCA methodology is also provided, as well as how it applies to the study of general anesthesia. We describe available LCA studies comparing the environmental impacts of a lower carbon footprint inhaled anesthetic, sevoflurane, to TIVA/propofol and discuss their life cycle steps: manufacturing, transport, clinical use, and disposal. Significant hotspots of GHG emission were identified as the manufacturing and disposal of sevoflurane and use (attributed to the manufacture of the required syringes and syringe pumps) for propofol. However, the focus of these studies was solely on GHG emissions, excluding other environmental impacts of wasted propofol, such as water/soil toxicity. Other LCA gaps included a lack of comprehensive GHG emission estimates related to the manufacturing of TIVA plastic components, high-temperature incineration of propofol, and gas capture technologies for inhaled anesthetics. Considering that scarce LCA evidence does not allow for a definite conclusion to be drawn regarding the overall environmental impacts of sevoflurane and TIVA, we conclude that current anesthetic practice involving these agents should focus on patient needs and established best practices as more LCA research is accumulated.

Environmental and Economic Life Cycle Assessment of Enzymatic Hydrolysis-Based Fish Protein and Oil Extraction

As global fish consumption rises, a large amount of waste is generated that is generally neglected. Considering the value embedded in these resources, sustainable methods become more important in extracting valuable ingredients from fish processing residues. Enzymatic hydrolysis is a fast and easily reproducible method for recovering protein ingredients and obtaining valuable by-products. To confirm its advantages, an environmental and economic impact assessment is essential. This study overviewed the sustainability and economic viability of extracting protein compounds and oil from Atlantic mackerel processing residues using enzymatic hydrolysis. Life cycle assessment (LCA) and life cycle cost analysis (LCCA) methods were employed. It was found that the climate change impact of the whole process was 0.073 kg CO2-eq per 1 g of fish protein hydrolysate (FPH). As the process produces FPH as the main product and fish oil as the by-product, economic allocation was used to distribute the impacts of FPH and fish oil. The findings of the LCCA showed that producing 1 g of FPH costs EUR 3.68. The contribution analysis indicated the crucial role of electricity and fish in environmental impacts. To ensure the accuracy of the calculation, the results of an LCA study published previously were recalculated. The sensitivity analysis showed that the results were susceptible to the region and source of electricity production. This research provides valuable insights into the sustainability and economic aspects of using enzymatic hydrolysis for extracting protein ingredients and oils from Atlantic mackerel. This can inform future investigations of environmentally friendly and economically viable solutions for extracting fish ingredients.

Novel bowl-like or capped carbon with a low carbon footprint as electrode material in EDLCs

Large surface area, excellent electrical conductivity, homogeneous structure, and extended cycling stability are desirable characteristics for energy materials. Carbon-derived structures exhibit porous structure, work well in a wide potential window, and are highly conductive. Hence, they can show enhanced rate capability and cycle life. Despite ongoing efforts, the synthesis of carbons at lower temperatures remains a challenge. In comparison, the high-temperature synthesis protocols lead to a high CO2 footprint. Here, we report the synthesis of unique carbon morphologies, namely capped carbon nanostructures (CCS) and bowl-like carbon structures (BCS). Their performances are either comparable or higher than those conventionally used morphologies of carbon, such as nanospheres, microspheres, nanotubes, graphene oxide, and layered structures. The four-sided opening in BCS particles ensures higher adsorption of electrolyte ions, which is even higher than hierarchical or spherical structures. The cap formation on the CCS acts like an additional layer on top of the sphere. Further, the CCS is arranged in a sequential honeycomb array, which leads to the formation of definitive channels for electrolyte diffusion. The unique carbon morphologies showed nearly ∼ 40 % increment in the specific capacitance values compared to other commonly used carbon structures. The novel morphologies also have a much lower carbon footprint, as shown by the life cycle assessment (LCA) studies.

Quality degradation in glass recycling: substitutability model proposal

The sustainability assessment of waste management systems requires tools capable of evaluating material quality degradation during recycling. Existing research has predominantly focused on the development of substitutability models for plastics, leaving a gap in addressing other materials like glass. Glass is commonly regarded as endlessly recyclable, even though its actual recyclability depends on several crucial factors, such as colour and pollutant contamination. Many Life Cycle Assessment (LCA) studies in this field assume a one-to-one substitution coefficient, neglecting material deterioration and inaccurately representing real-world scenarios. This study proposes and assesses a substitutability model for glass, aiming to measure the replacement extent between virgin materials and recycled crushed glass (cullet). The methodology is based on two key factors: technical quality substitutability, considering impurities and colour contaminations in cullet, and market applicability, accounting for market demand. Once formulated, the model was applied to a European case study on glass waste treatment. Two scenarios were considered: one assuming complete substitution between cullet and raw materials, the other incorporating quality degradation. Findings indicate that, accounting for quality degradation, only 83% of cullet effectively replaces raw materials, resulting in a decrease of the benefit associated with recycling of 13–23% for the different examined impact categories, compared to complete replacement assumption. This underscores the importance of considering quality deterioration in glass recycling impact assessments.

Assessing the environmental impacts of soilless systems: a comprehensive literature review of Life Cycle Assessment studies

Assessing the environmental impacts of soilless systems: a comprehensive literature review of Life Cycle Assessment studies

Beyond flight operations: Assessing the environmental impact of aircraft maintenance through life cycle assessment

As the aviation industry strives to minimise its environmental footprint, understanding the full life cycle impacts, including maintenance, becomes essential for sustainable development. This paper addresses the critical research gap in the environmental assessment of aircraft maintenance by conducting a comprehensive life cycle assessment based on an Airbus A320 aircraft. By combining a top-down check-level analysis and a detailed examination of the aircraft manufacturer’s maintenance planning document, this study provides significant insights into the environmental implications of maintenance activities. The check-level analysis provides a general overview, while the analysis of the maintenance planning document delves into individual tasks, enabling the identification of components with the highest ecological impacts. This research emphasises the importance of including aircraft maintenance activities in life cycle assessment studies and provides valuable guidance for researchers, industry practitioners, and policy makers in prioritising sustainability measures and enhancing the environmental performance of aircraft throughout their life cycle.

Fly ash treatment via conventional and microwave-assisted organic acid leaching: kinetics and life cycle assessment.

Heedless disposal of oil-based fly ash contributes to the contamination of the air, water, and soil. Acid leaching of industrial solid wastes is recognized as a versatile, cost-effective, and environmentally friendly solid waste treatment approach. The present study investigated the viability of conventional leaching (CL) and microwave-assisted leaching (MAL) of predominant heavy metals from Mazut-burnt fly ash. For this purpose, the practicality of four organic acids with various specifications (ascorbic, gluconic, citric, and oxalic acids) on the dissolution efficiency of fly ash components was examined. Utilization of oxalic acid led to achieving full V recovery, complete Fe removal, and Ni enrichment in the residue in both CL and MAL setups. The Ni content of the sample was enriched from 6% in the calcinated sample to 23.7% in the oxalic acid leaching residue. Using citric acid resulted in the co-extraction of V, Ni, and Fe with nearly 70% V, 50% Ni, and 89% Fe dissolved in CL. The dissolution efficiencies were slightly lower in MAL. Oxalic acid was selected as the most promising organic acid reagent for fly ash treatment, so its CL kinetics was studied and defined by the shrinking particle model. The model showed that the controlling steps in the leaching of V differ over time, changing from a chemical reaction before 60min to fluid film diffusion or mixing afterward. The kinetic study proved MAL as an effective technique in overcoming the leaching kinetic barriers. A life cycle assessment study was conducted to determine the environmental impacts of the proposed process. Accordingly, the MAL using oxalic acid was the most environmentally friendly process among the studied ones, and the utilization of microwaves leads to the reduction of the leaching processes' environmental impacts by decreasing the processing time.

Substitution modeling can coherently be used in attributional life cycle assessments

AbstractMost life cycle assessment (LCA) studies use the attributional methodology. This approach attributes a share of global environmental impacts to one or multiple functions provided by a normatively circumscribed system. Multifunctional systems that are not technologically subdivisible between co‐functions are frequently encountered in LCA studies. It then becomes necessary to resort to co‐production modeling techniques, like the substitution approach. The use of substitution modeling in attributional LCA (ALCA) is, however, discouraged amongst practitioners, due to the alleged violation of central requirements of the attributional methodology. The objective of this research is to shed light on common misconceptions about the compatibility of substitution with ALCA. The first misconception is that the use of substitution in ALCA violates the conservation of total environmental impacts. We find that this idea arises from a confusion regarding the attribution of impacts to the secondary product(s). The second misconception stipulates that substitution is not coherent with the state‐descriptive characteristic of ALCA. We conclude that we can describe a given system as resulting from an inferred (substitution) change, rather than as disrupted by this change. Finally, we discuss the choice of the substituted technology, and argue there is a logic to marginal substitution in ALCA. We therefore recommend accepting substitution modeling in ALCA.

How does plastic compare with alternative materials in the packaging sector? A systematic review of LCA studies.

In the recent years, packaging made of conventional plastics has been increasingly replaced by materials believed to be more sustainable. However, perceived sustainability must align with scientific assessments, such as life cycle assessments (LCAs). This review analysed 53 peer-reviewed studies published in the time range 2019-2023, aiming at understanding the state of the art in LCA about the environmental impacts of packaging by focusing on the comparison between plastics and alternative materials. The literature showed that consumer perceptions often differ from LCA findings and revealed that, frequently, conventional plastics are not the least environmentally friendly choice. Bioplastics typically show benefits only in the climate change and the fossil resource depletion impact categories. The heavy weight of glass turns out to affect its environmental performances with respect to the light plastics, with reuse being an essential strategy to lower the burdens. The comparison between plastics and metals is more balanced, leaning more towards plastics for food packaging. Similarly, article resulted often preferable than plastics. Finally, for the other materials (i.e. wood and textiles), the picture is variable. To be competitive with plastics, the alternative materials require improvements like the optimisation of their production processes, their reuse and enhanced end-of-life options. At the same time, recycled polymers could boost the eco-performance of virgin plastics.

Biological wastewater treatment: a comprehensive sustainability analysis using life cycle assessment.

The research conducts a life cycle assessment (LCA) on wastewater treatment (WWT) methods-membrane bioreactor (MBR), soil biotechnology (SBT), and bio-electrochemical constructed wetlands (BCW)-in comparison with the conventional activated sludge process (ASP). Employing SimaPro v9.5 with a cradle-to-gate system boundary, the analysis utilizes the IMPACT 2002 + method, employing per cubic meter of treated wastewater as the functional unit. The analysis shows that SBT exhibits the lowest environmental impacts among the considered WWT methods. The global warming potential was 0.0996 kg CO2 eq. for SBT, 1.33 kg CO2 eq. for MBR, 0.131 kg CO2 eq. for BCW, and 0.544 kg CO2 eq. for ASP. BCW demonstrates a 75.91% decrease, while MBR exhibits a 144.48% increase compared to ASP. Notably, electricity consumption emerges as the primary contributor to environmental impact in MBR and ASP. The resource impact category varies with a 138.15% increase in MBR and an 83.41% decrease in SBT compared to ASP. Additionally, the research indicates that the high human health impact observed in MBR results mainly from increased carcinogens (0.00176 kg C2H3Cl eq.), non-carcinogens (0.01 kg C2H3Cl eq.), and ionizing radiation (3.34 Bq C-14 eq.). The findings underscore the importance of considering treatment efficiency and broader environmental implications in selecting WWT methods. As the world emphasizes sustainability, such LCA studies provide valuable insights for making informed decisions in wastewater management.

Innovative pilot-scale process for sustainable rare earth oxide production from coal byproducts: A comprehensive environmental impact assessment

This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage (AMD) streams to recover rare earth elements (REEs). A life cycle assessment (LCA) study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate (HCL) and low-contaminated leachate (LCL). The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and electricity. Also, oxalic acid, Na2CO3, and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides (REOs), including solvent extraction (SX) and precipitation steps. The HCL route has higher environmental impacts than LCL due to higher chemical/energy and H2SO4 usage, so 468 and 292 kg of carbon dioxide are generated to produce 1 t of individual REOs from HCL and LCL routes, respectively. Moreover, the carbon dioxide emitted from the process, including the RE-hydroxide production, SX, and REOs production, is less than 10 t CO2. A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process, as the main stage has a higher contribution to the whole process. This LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.

Life cycle assessment of bioproducts from bamboo residues with biphasic phenoxyethanol-acid based biorefinery technology

Utilizing bamboo residues to produce decarbonization energy products or materials diverts wastes from low-value treatment and supports the circular bioeconomy at the same time. This study develops a cradle-to-grave life-cycle assessment (LCA) for a biorefinery converting bamboo residues into bioproducts (ethanol, polylactic acid (PLA), and bio-based wood adhesive) in China. To combat the low enzymatic hydrolysis performance of bamboo residues and valorize the lignin, this study adopts a biphasic pretreatment by coupling phenoxyethanol and sulfuric acid solution (1%) to achieve high fermentable sugar production. The LCA study is coupled with a process simulation for an industrial-scale biorefinery based on the experimental data. Our results show that the life-cycle Global Warming Potential (GWP) is 17.0–32.1 gCO2e/MJ for ethanol cases and 3.2–3.7 kgCO2e/kg for PLA cases, when biphasic pretreatment is adopted. The lower GWP values are achieved by using 1:1 phenoxyethanol: acid solution, though it has a lower product yield than 4:1 phenoxyethanol: acid solution cases. Without biphasic pretreatment, the GWP is 135.8 gCO2e/MJ ethanol and 4.4 kgCO2e/kg PLA. For the perspective of treating 1 dry t bamboo residues, with biphasic pretreatment, the GWP is −174 to −66 kgCO2e for ethanol cases and −542 to −432 kgCO2e for PLA cases. The lower GWP is also from using 1:1 phenoxyethanol: acid solution (1%). These GWP ranges are lower than conventional landfilling (2969 kgCO2e) and landfilling with landfill gas recovery (−28 kgCO2e).

Environmental sustainability practice of sewage sludge and low-rank coal co-pyrolysis: A comparative life cycle assessment study

This study attempts to bridge the current research gaps related to the environmental burdens of low-rank coal (LRC) and sewage sludge (SS) co-pyrolysis potentially. The life cycle assessment (LCA), energy recovery and sensitivity analysis were investigated for different proportions of LRC and SS (co-)pyrolysis. The results showed that the LRC/SS pyrolysis mitigated the environmental burden with an average improvement of 43 % across 18 impact categories compared with SS pyrolysis. The best net values of energy and carbon credits were identified in SL-4 with −3.36 kWh/kg biochar and − 1.10 CO2-eq/kg biochar, respectively. This study firstly proposed an optimal LRC/SS co-feed proportion at 3 to 7, which achieves the acceptable environmental burden and satisfactory energy recovery. Moreover, sensitivity analysis demonstrated this proportion is robust and adaptable. LRC/SS co-pyrolysis is a promising and sustainable alternative for SS disposal, which could meet the imperative of carbon emission mitigation and resource recycling.

Life cycle environmental impacts of kelp aquaculture through harmonized recalculation of inventory data

As seaweed farming gains prominence in future blue economies, scientifically robust environmental evaluations are vital. Harmonizing life cycle assessment (LCA) studies provides nuanced insights, allowing generalizations and potentially more accurate results than individual studies. This study recalculates life cycle inventory (LCI) data to offer a comprehensive perspective on sugar kelp Saccharina latissima. The findings affirm and validate previous studies, emphasizing critical hotspots such as fuel use for boats at sea, impacts from the use of plastic ropes, buoys and metal components at sea, and electrical energy use in the hatchery. The overall environmental impacts of seaweed farming remain relatively low compared to other seafood and biomass sources. The study also highlights the importance of how fuel use is modelled for the outcome. While harmonization enhances certainty and facilitates robust comparisons, challenges arise from the lack of standardized methods for data collection and reporting, along with data gaps between studies. Addressing these limitations calls for standardized protocols and improved data sharing practices in the field.

Substantiating 'green' healthcare decisions: an explorative life cycle assessment study to identify differences in greenhouse gas emissions between general vs. regional anaesthesia for upper extremity surgery.

Substantiating 'green' healthcare decisions: an explorative life cycle assessment study to identify differences in greenhouse gas emissions between general vs. regional anaesthesia for upper extremity surgery.

Dietary Concentrate Supplementation Increases Milk Production and Reduces Predicted Greenhouse Gas Emissions Intensity in Pasture-based Commercial Dairy Farms

Controlled studies have extensively documented that concentrate supplements typically increase enteric methane (CH4) emissions and milk yield and reduce emissions per unit of milk produced and dry matter intake. However, there have been no studies conducted to determine the effect of concentrate on predicted greenhouse gas emissions from dairy farms representing the Australian pasture-based farming system. Thus, this study sought to determine how dietary concentrate supplementation affects enteric and manure CH4, and N2O of Australian pasture-based dairy farms. The Australian Dairy Carbon Calculator was used, which incorporates emission factors and methodologies used in the National Greenhouse Gas Inventory as reported to the International Panel on Climate Change. Primary data were collected and analyzed from 120 commercial farms in Australia's major dairy regions. Then the farms were divided into 4 groups based on their dietary concentrate supplementation: ≤ 1 (low; 15 farms), 1-2 (moderate;35 farms), 2-3 (high; 35 farms), and ≥ 3 (very high; 35 farms) ton (t) of concentrate dry matter per cow per year. Sources of greenhouse gas emissions were CO2 from concentrate production, enteric CH4, and manure CH4 and N2O. Total dry matter intake, milk yield, and daily enteric CH4 production (g/day) quadratically increased with concentrate level, whereas greenhouse gas emission intensity of milk production (kg CO2eq/kg fat and protein corrected milk) decreased by 14% for farms supplementing with ≥ 3 tDM/cow per year compared with those supplementing with ≤ 1 tDM/cow per year of dietary concentrate. The emissions of N2O and CH4 from manure increased quadratically and linearly, respectively, with the increasing supplementation of concentrate. Farms supplementing 2-3 tDM/cow per year showed substantial increases in gross income, gross margin, earnings before interest and tax, and net income ($/cow/year) compared with those supplementing of ≤ 1, 1-2, and ≥ 3 tDM/cow per year. In conclusion, increasing dietary concentrate supplementation for dairy cows resulted in increased milk production per cow, reduced greenhouse gas emissions per unit of milk produced, and increased income and profit. However, a comprehensive life cycle assessment study is needed to account for carbon sequestration by other farm components such as pastures and trees, which were not considered in the present study. In addition, the present study was based on modeling and did not gather ground truth information for DMI, digestibility, crude protein, and urinary and fecal N excretion. Therefore, data should be interpreted with caution, and studies gathering such information are encouraged.

Assessing the environmental impact of plastic flows in urban areas: A life cycle assessment and scenario analysis study

Urban areas have a considerable impact on the environment. Among the sectors contributing to the environmental impacts is plastic product usage, resulting in urban plastic waste accumulation. There exists a need to determine and evaluate plastic flows and their environmental impacts in urban areas. Our research comprehended the modelling of the eight most commonly used plastic polymers in a system of a European city with 10^5 inhabitants for the year 2020. A scenario analysis was conducted, considering the European Union's policy of achieving a 65 % recycling rate by 2035. Plastic production contributes to most environmental impacts during the life cycle, where polyurethane, polystyrene and other plastic types are at the forefront. The results per waste management options revealed that recycling is still preferable for plastic waste, followed by incineration and landfill. Recycling potential was further noted during the scenario analysis, where an increased recycling fraction following the EU's policy could decrease the environmental impacts of global warming by a margin of 20 %–45 % and fossil resource scarcity by a margin of 20 %–52 % per individual plastic polymer. While the established model indicates potential benefits, improved data collecting, and further research are needed to improve the model and establish a plastic nexus within urban areas.

Life cycle assessment on environmental feasibility of microalgae-based wastewater treatment for shrimp recirculating aquaculture systems

This life cycle assessment (LCA) study analyzed the environmental consequences of integrating microalgae-based wastewater treatment into a shrimp farm with recirculating aquaculture systems (RAS). Microalgae treatment produced <10 % of the system’s freshwater eutrophication potential (FEP), marine eutrophication potential (MEP) and global warming potential, which was dominantly contributed by electricity use. Microalgae treatment performed comparably to activated sludge treatment for FEP reduction, and was more effective in remediating marine eutrophication. Replacing coal in electricity mix, particularly with renewables, reduced the system’s impacts by up to 90–99 %. Performing the LCA based on system expansion generally obtained higher impacts compared to allocation. Utilizing algal biomass for biogas production reduced the MEP; however, production of feed ingredient and biodiesel were not environmentally beneficial. This study proved the use of microalgae for aquaculture wastewater treatment to be environmentally feasible, the results can guide more sustainable RAS operations and design of full-scale microalgae treatment.

Lithium-ion (LCO/NMC, NMC, LFP) battery recycling: partial LCA study

AbstractRecycling lithium-ion batteries (LIBs) have become increasingly important in response to expanding electromobility. This paper is focused on evaluating the environmental impacts (EIs) of recycling pre-treatment of three types of LIBs with black mass as its product. A detailed gate-to-gate Life Cycle Assessment study was conducted to obtain EIs of the recycling process. The benefits of LIBs recycling pre-treatment and significant recovery of secondary aluminum for compared battery types are highlighted in the analysis. This paper points out that the varying chemistry of the compared LIBs does not affect the resulting EIs of the recycling pre-treatment procedures. Graphical abstract

Sustainability Analysis of Landfill Cover System Constructed Using Recycled Waste Materials by Life Cycle Assessment

The sustainability of using industrial by-products for the construction of landfill cover was determined using Life Cycle Assessment (LCA). LCA was carried out on four materials: sand- bentonite mix, red earth- bentonite mix (amended soil), Waste Foundry Sand (WFS)- Bentonite mix, and WFS- marine clay mix. The former two are commonly used cover soils and the latter two are alternative materials proposed. Environmental impacts based on the extraction of resources, processing, transportation to the site, and site preparation were considered using the ‘cradle to site’ approach. Analysis was carried out in OpenLCA software using the ReCiPe (H) Midpoint method of impact assessment. Required data for analysis was taken from the Ecoinvent database supplemented with inputs from a field survey. The use of WFS in landfill cover systems was found to be sustainable using LCA studies when compared to conventional materials.