Simplified Life Cycle Assessment Research Articles

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. The methodology consisted of testing different combinations of the alkaline activator, in terms of sodium oxide/binder (4%, 6%, 8%, 10%, 15%) and silica/sodium oxide ratios (0, 0.5, 1.0, 1.5, 2.0), and understanding the influence on the mortar's mechanical performance. The materials were evaluated in their fresh (density and workability) and hardened state (dry density, compressive and flexural strengths, and modulus of elasticity) after 7, 28, 91 and 182 days. The first stage corresponded to the precursor's pre-treatment in a NaOH 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% vs. 8% for fly and bottom ash, respectively). The results of a simplified life cycle assessment showed that such mixes exhibit lower overall CO2 emissions (‘Global Warming Potential’ category), when compared with cement-based counterparts. However, this trend reverses with increasing content of sodium hydroxide and sodium silicate.

Characterizing the packaging waste generation patterns and carbon emissions of university delivery service

As the main consumer group for online shopping and ordering fast food, young people—particularly university students—have contributed to a substantial amount of packaging waste. In the present study, the material flow method was employed to quantify the generation and end-of-life flows of packaging waste from both the express delivery and food delivery sectors at universities in China. Moreover, this study takes reusable packaging materials for food delivery services as a case study to evaluate their environmental benefits through a simplified life cycle assessment approach. The results show that approximately 1.7 (±0.3) million metric tons and 123 (±1.0) kilo metric tons of packaging waste were generated from express delivery and food delivery services, respectively, for university students in 2021. Although reusable food packaging is more complex and costly than regular disposable food packaging is, our modeling results show that reusable food packaging has significant emission reduction benefits under the current practice of 63 cycles per year of actual operation at a specific university. The reusable packaging mode in universities is feasible from an environmental perspective; however, it faces significant challenges due to a few concerns among stakeholders, such as high costs and inadequate recycling supply systems.

Environmental concerns on the use of the electrospinning technique for the production of polymeric micro/nanofibers

The production of micro and nanofibers through the electrospinning technique is a well assessed technology that finds application in a variety of fields. Indeed, the specific features of electrospun fibers, as well as the possibility to be modelled and functionalized, ensure their great versatility. In the last decades, the widespread use of electrospun fibers promoted studies related to the evaluation of both human health and environmental risks associated to their handling and exposure. However, to date, the environmental impact strictly related to the use of the manufacturing process has been barely considered. Therefore, the present work aims to assess the environmental impacts of the electrospinning technology used to produce micro and nanofibers. To this purpose, a model polymer was systematically electrospun, varying the main system, process and external parameters, that control the electrospinning technique. A simplified life cycle assessment analysis was finally used to evaluate how the fibrous morphology, closely linked to the choice of the technological parameters, intrinsically affected the environmental impacts.

Assessing sustainability and green chemistry in synthesis of a Vanillin-based vitrimer at scale: Enabling sustainable manufacturing of recyclable carbon fiber composites

Sustainable manufacturing of carbon fibre (CFs) reinforced polymer (CFRP) composites featured technically by low-cost and rapid manufacturing techniques, use of renewable materials, and non-destructive recycling process. By developing an inherently recyclable thermoset, this research bridges between these three components of sustainable manufacturing by focusing on a fast cured vanillin-based Schiff base polyimide network in all-solid state. In this study, a multifunctional vanillin-based monomer was synthesised at scale in water which can be cured using a diamine without requiring any organic solvent. A CFRP was fabricated using this newly developed Schiff base polymer using compression moulding technique, and its mechanical and thermal/fire performance were compared to a CFRP made of a commercially available automotive grade epoxy resin. The resulting Schiff base CFRP composite demonstrated exceptional fire retardancy, complemented by remarkable tensile strength and modulus values of 427 MPa and 45 GPa, respectively. These characteristics meet the criteria for a broad spectrum of high-performance applications. In contrast to conventional CF reclaiming processes, a novel and efficient chemical recycling approach was introduced, enabling the delamination of CF layers containing the Schiff base network without requiring the separation and purification of the polymer matrix. This approach facilitates the low-cost remanufacturing of new CFRP composites with mechanical performance comparable to the original composite. Finally, green chemistry matrices as well as simplified life cycle assessment (LCA)-like approaches, including the EcoScale and GREEN MOTION rates, were employed to evaluate the efficiency and environmental impact of the CFRP manufacturing process.

Prototype of alveolar gypsum blocks with plastic waste addition for partition walls: Physico-mechanical, water-resistance and life cycle assessment

The development of eco-friendlier building products incorporating waste as an alternative to raw materials has become increasingly relevant within the construction industry. With this in mind, this study presents a prototype of an alveolar gypsum block for partition walls, wherein partial replacement of the binder (i.e. gypsum or cement) was made using two types of plastic waste (i.e. polypropylene- and nylon-based). Two plastic waste-containing composites, with contents considered as optimum in previous studies (AGB/PP/7.5–7.5 wt% polypropylene content; AGB/PA6/2.5–2.5 wt% nylon content), were produced and extensively analysed in comparison to a reference block. Physico-mechanical (bulk density, surface hardness, flexural and compressive strength), water permeability and thermal properties were evaluated and compared to commercially available counterparts. In addition, the prototypes’ environmental impact was determined by conducting a simplified life cycle assessment primarily based on the “Global Warming Potential” and “Embodied Energy” categories. The results showed a widespread improvement in the mechanical performance of plastic-containing blocks and more so for those reinforced with nylon fibres when compared to the reference product. Furthermore, notable reductions in thermal conductivity and water permeability were observed on the blocks due to the addition of plastic waste. Both types of blocks presented a slight environmental impact decrease because of the reduction of raw materials (i.e. gypsum). These findings are encouraging from a practical application point of view and may create a notable opportunity for replacing more frequently gypsum with polypropylene- or nylon-based wastes for alveolar blocks for building partition walls.

The Green Value Engineering Methodology: A Sustainability-Driven Project Management Tool for Capital Projects in Process Industry

Process industry renovation is mostly driven by business objectives like productivity enhancement and cost reduction, which hinder the “shift towards a sustainable manufacturing” called by political and academic institutions. In this paper, the project management methodology of Value Engineering, used for cost reduction in large capital projects, is extended to improve not only economic figures, but also environmental sustainability indicators. The methods can guide project design to reduce the consumption of natural resources and the generation of waste, closing a gap between sustainability targets and production needs. Sustainability metrics derived from a simplified life cycle assessment approach are used to achieve quick but reliable estimates of the environmental impact reductions against a base scenario. The project governance is thus supported when assessing potential trade-offs between environmental and economic advantage, encouraging shared and de-risked decisions. Even though limited by the project boundaries of time and budget and by the simplified impact assessment approach, the method promotes a lean and incremental implementation of sustainable manufacturing practices, applicable also to routinary interventions. The methodology is illustrated through application examples from a real case study, an EUR 100 M chemical plant expansion project for a pharmaceutical company in Italy.

From full life cycle assessment to simplified life cycle assessment: A generic methodology applied to sludge treatment

Life cycle assessment is widely used to evaluate sludge treatment methods. However, detailed life cycle assessment is time-consuming and resource-intensive. In addition, the complex characteristics of sludge and the variety of treatment methods increase the difficulty of sludge treatment life cycle assessment. There is an urgent need to develop simplified life cycle assessment models to allow rapid decision-making. This study proposes a simplified method of sludge treatment life cycle assessment based on logistic regression analysis. The simplified model relies on the total environmental impact and very few or even a single input parameters. Contribution and data quality analysis were introduced to identify key input parameters and to obtain model training data. The method was eventually applied to traditional sludge treatment methods, showing that it can quickly and accurately predict environmental impact. Representative analysis showed that the model would be affected by technology and energy structure modification. It is hoped that this study will provide a reference and new perspectives for a simplified life cycle assessment of sludge treatment.

Comparison of waste photovoltaic panel processing alternatives in Australia

This work aims to compare end-of-life (EoL) alternative processing scenarios of waste photovoltaic panel in Australia. Landfill, generic waste electrical and electronic equipment recycling (European business-as-usual (EU BAU)), full-recovery EoL photovoltaic (FRELP), and Modified FRELP are the alternative processing scenarios considered for the next five years. Environmental analysis by a simplified life cycle assessment is performed using Material, Energy, Chemical, and Other (MECO) matrix. This semi-quantitative comparison eliminates reliance on LCA software and environmental expertise for preliminary screening. Financial analysis is also performed by using a life cycle costing (LCC) approach. Overall, comparative findings are consistent with full-quantitative LCA and LCC despite magnitude differences. Simplified analysis merely reflects process complexity and resource consumption. A full financial insight can only be acquired when non-resource-derived costs are incorporated. Considering the increasing trend of waste levies and landfill ban extending into the future, landfill is no longer the cheapest option in Australia. Consequently, mass-based waste recovery for landfill diversion facilitates cost savings. Recovering 8% more waste with FRELP compared to modified FRELP has the potential to save $19 more per tonne of processed PV waste. EU BAU is the most eco-efficient interim solution, while waste volume is still low. Modified FRELP saves 321 kg CO2-e emission by avoiding traditional incineration. The focus on reclaiming solar-grade silicon rather than silver has the potential to attract $154 more revenue per tonne compared to FRELP.

Approaches for assessing embodied environmental effects during the building design process

Buildings and construction are among the leading contributors towards global greenhouse gas emissions, resource demands, waste, and pollution, placing a massive strain on our natural environment. Until recently, mitigation strategies have primarily concentrated on reductions in operational energy, failing to account for embodied effects; those associated with the manufacture of construction goods, construction activities, and end of life considerations. In recent years, there has been an increased recognition of the growing significance of embodied effects, and the opportunity to reduce these during the building design process. However, life cycle assessment (LCA) tools used to quantify environmental flows are often perceived as being too time-consuming or complicated to incorporate into prevalent building design workflows. The aim of this study was to review approaches for assessing embodied environmental effects during the building design process, including the LCA tools and environmental data used to achieve this. A systematic review was conducted of academic and grey literature. The study identified three main approaches for incorporating LCA into the building design process: simplified LCA, detailed LCA and incremental LCA. Further analysis of these approaches was conducted, based on case studies. General attributes and design considerations were identified, and mapped against the early design, and detailed design stages. A wide variety of LCA approaches were reviewed, responding to various challenges for incorporating LCA into the building design process, with no singular approach able to completely satisfy all requirements. Findings highlight the lack of incremental LCA approaches, and the need for further research to understand how LCA approaches can be better used to improve the embodied environmental performance of buildings during the design process.

Service life optimization and life cycle assessment of concrete using SCMs as partial replacement of cement

Developing a concrete mixture with the lowest possible environmental impacts while improving durability performance is crucial for a sustainable environment. In this study, a Base Case Scenario (BCS) and Alternative Case Scenario (ACS) concrete mixtures were developed with identical water-to-cement ratio (w/c) of 0.4, having cement substitution of 0% and 34%, respectively. Supplementary cementitious materials (SCMs) such as silica fume, fly ash, and slag cement were implemented as cement replacing mineral admixture. A simplified life-cycle assessment (LCA) was performed to determine environmental impact reduction factors such as fossil fuel depletion, ecotoxicity, ozone depletion, carcinogenic, and global warming. Then a simulation-based approach was carried out to optimize the durability performance of concrete mixtures using Life365™. As a result, a 24.9% reduction of environmental impacts was observed with a decent service life optimization in ACS compared to the BCS mixture.

Assessment of Sustainability and Efficiency Metrics in Modern Methods of Construction: A Case Study Using a Life Cycle Assessment Approach

The construction industry faces various sustainability challenges, and modern methods of construction (MMC) have been promoted as an effective alternative to mitigate environmental impact and improve productivity. However, to gain a thorough understanding of the benefits, there is a need for more objective data. To address this, the present study employs a simplified life-cycle assessment (LCA) methodology to evaluate a set of environmental and efficiency metrics in a case study. The study aims to demonstrate the benefits of using an MMC known as the “VAP system” by comparing it with its conventional counterpart built with reinforced masonry. Adopting the MMC resulted in significant reductions in embodied carbon (EC) and embodied energy (EE) related to materials, as well as a reduction in global warming potential (GWP), cumulative energy demand (CED), and construction waste. Additionally, it shortened delivery times and increased labor productivity. Furthermore, when both local and European parameters were considered in the evaluation, the percentage of materials circularity (PMC) was higher. The study concludes that the adoption of the MMC leads to higher sustainability by reducing carbon emissions, minimizing construction waste, and conserving resources. This research has significant implications for promoting the adoption of MMC globally, leading to more sustainable and efficient construction practices.

A Circular Economy for O'ahu's Management of Single-Use Plastics

Ever since Single-Use Plastics (SUPs) became a ubiquitous part of our daily lives, societal emphasis has generally been on downstream management – such as recycling efforts and cleanups – of SUP waste. Less attention has been given to upstream management, such as extended producer responsibility (EPR), assigning producers the stewardship responsibility at the end-of-life of their products. Life cycle assessment (LCA) is helpful in initiating upstream management by assessing the ecological impact at every stage of a product, from the extraction of raw materials to packaging and use to the end-of-life management. Understanding the life cycle of SUPs is critical to mitigating the unsustainability issues that SUPs create. The complexity of SUP pathways across human settlements makes it difficult to conduct LCAs as precursor to designing and realizing a more circular economy. Thus, island settlements may provide insightful implications due to fewer points of SUP entry and removal than vast, interconnected continental communities. Therefore, islands may serve as useful models to investigate, critique, and address negative externalities revealed by LCAs. This study focuses on the island of O‘ahu in the state of Hawai‘i and a simplified life cycle assessment is conducted for the most prevalent SUPs. After quantitative and qualitative data are analyzed, circular economy approaches for SUP management on the island are identified, described, and assessed for applicability to O‘ahu’s context.

Using waste poly(vinyl chloride) to synthesize chloroarenes by plasticizer-mediated electro(de)chlorination.

New approaches are needed to both reduce and reuse plastic waste. In this context, poly(vinyl chloride) (PVC) is an appealing target as it is the least recycled high-production-volume polymer due to its facile release of plasticizers and corrosive HCl gas. Herein, these limitations become advantageous in a paired-electrolysis reaction in which HCl is intentionally generated from PVC to chlorinate arenes in an air- and moisture-tolerant process that is mediated by the plasticizer. The reaction proceeds efficiently with other plastic waste present and a commercial plasticized PVC product (laboratory tubing) can be used directly. A simplified life-cycle assessment reveals that using PVC waste as the chlorine source in the paired-electrolysis reaction has a lower global warming potential than HCl. Overall, this method should inspire other strategies for repurposing waste PVC and related polymers using electrosynthetic reactions, including those that take advantage of existing polymer additives.

Can bioleaching of NIB magnets be an answer to the criticality of rare earths? An ex-ante Life Cycle Assessment and Material Flow Cost Accounting

The instability of rare earth elements (REEs) supply chains due to, among others, geopolitical factors brought alternative sources of REEs under the spotlight. Waste from electrical and electronic equipment (WEEE) is considered one of such sources. WEEE recycling is seen as a way not only to mitigate the aforementioned REEs supply risk but also to benefit the environment and society caught currently in a precarious position. Within this context, bioleaching for REEs recovery is gaining attraction, considering that, so far, this process has mainly been used to recover other elements (e.g., Cu, Ni, Zn, Al, Au, Ag). Hitherto, a few lab-scale studies on Nd, Dy, and Pr bioleaching from NIB magnets were identified in the open literature, whereas only one study attempted to perform a simplified LCA analysis of the process. Ergo, this study aims at filling this knowledge gap. For this purpose, the Life Cycle Assessment (LCA) and Material Flow Cost Accounting (MFCA) were performed to assess the process' environmental and economic feasibility after scaling it up from a lab to a pilot scale. Moreover, a break-even analysis was performed to assess the competitiveness of the technology. As the bioleaching of NIB magnets is an emerging concept, this study aimed to identify future process optimisation and development directions. The process was divided into six stages (i.e., demagnetising, shredding, bacteria cultivation, bioleaching, REEs extraction, and oxidation), analysed individually and collectively. Electricity and oxalic acid consumption, together with investment costs, were identified as the main hotspots for future improvement. • Permanent NIB magnets can be recycled to recover rare earth elements. • Nd, Dy and Pr bioleaching from these magnets is a promising emerging technology. • Environmental and economic hotpots of this technology were identified. • Electric energy and oxalic acid consumption resulted environmentally impactful. • High investment costs might compromise the profitability of the process.

Towards selecting the optimized external wall solution in Iran: Comparison between life cycle assessment (LCA), cost benefits, and thermal performance

External walls, as the main components of a building's envelope, directly affect the building's thermal and environmental performance due to their high carbon emissions, life cycle costs, and user comfort. As the buildings are responsible for one-third of global GHG emissions, choosing the most effective solutions for external walls is crucial to combat the environmental crisis. This paper aims to identify and assess conventional external walls in Iran. A multi-criteria scoring system is established to evaluate them regarding carbon emissions, cost benefits, and thermal performance (R-value). A selection criteria is defined, and a total of 45 external walls are identified and categorized into three wall types: solid, filled cavity, and partial cavity walls. Assessing environmental impact involves conducting a cradle-to-handover simplified life cycle assessment. Cost assessment is performed using construction costs, and thermal performance assessment is conducted based on thermal conductivity coefficient and thickness. Based on the results, the highest scores belong to partial cavity walls. Partial cavity walls perform better than simple and filled cavity walls, although the simple wall is Iran's most widely used wall solution. The manufacturing stage represents the more significant contribution to environmental impact in all cases, followed by transportation and construction. The environmental analysis indicates that the structural layer (53.7%), followed by external finishing (14%), and transportation (12.1%) are the three highest contributors, respectively. The results also stress the importance of transport protocols in the carbon emissions reduction of external walls by indicating the structural layer as a carbon hotspot.

Parametric Approach to Simplified Life Cycle Assessment of Social Housing Projects

The provision of sustainable housing solutions is one of the main challenges in emerging economy countries. Furthermore, it is clear that a sustainable solution should be based on renewable bio-based materials. Scientific and practical evidence clearly suggests that the use of bamboo in the provision of housing solutions provides communities with both environmental and socio-economic benefits via this strategy. One barrier to the promotion of this type of solution is the lack of knowledge on structural design and environmental performance. Moreover, access to assessment tools and methodologies is limited. The use of simplified Life Cycle Assessment (LCA) has exhibited great potential to increase accessibility, but the generation of life cycle inventory data remains a major issue. In this paper, we describe the development of a methodological approach to use parametric design to generate the data required to carry out simplified LCA of social housing solutions. Moreover, we present a case study assessing a housing unit using cement bamboo frame technology developed by the Base Bahay Foundation in the Philippines. The main parameters for the LCA of the buildings were identified through sensitivity analysis. Moreover, they show that parametric design is a valid approach to overcome the challenges of data generation at early stages of design. The proposed approach would enable users without civil and/or engineering background to carry out simplified LCA calculations. Thus, through methodological approaches, it is possible to reduce significantly the complexity associated with LCA and open new avenues for it application.

Life Cycle Based Climate Emissions of Charcoal Conditioning Routes for the Use in the Ferro-Alloy Production

Renewable reductants are intended to significantly reduce CO2 emissions from ferro-alloy production, e.g., by up to 80% in 2050 in Norway. However, charcoals provide inferior properties compared to fossil fuel-based reductants, which can hamper large replacement ratios. Therefore, conditioning routes from coal beneficiation was investigated to improve the inferior properties of charcoal, such as mechanical strength, volatile matter, CO2 reactivity and mineral matter content. To evaluate the global warming potential of renewable reductants, the CO2 emissions of upgraded charcoal were estimated by using a simplified life cycle assessment, focusing on the additional emissions by the energy demand, required chemicals and mass loss for each process stage. The combination of ash removal, briquetting and high-temperature treatment can provide a renewable coke with superior properties compared to charcoal, but concomitantly decrease the available biomass potential by up to 40%, increasing the CO2-based global warming potential of industrial produced charcoal to ≈500 kg CO2-eq. t−1 FC. Based on our assumptions, CO2 emissions from fossil fuel-based reductants can be reduced by up to 85%. A key to minimizing energy or material losses is to combine the pyrolysis and post-treatment processes of renewable reductants to upgrade industrial charcoal on-site at the metallurgical plant. Briquetting showed the largest additional global warming potential from the investigated process routes, whereas the high temperature treatment requires a renewable energy source to be sustainable.

Identification of the Main Environmental Impact Categories Over the Life Cycle of Hot Mix Asphalt: An Application to Green Public Procurement

Increased environmental awareness has led road agencies to consider the implementation of green public procurement (GPP). Besides sustainability rating systems, environmental indicators can also be implemented in GPP to help road agencies make informed decisions about the environmental impact of the pavement works they procure. A vast literature review revealed that it is still unclear which impact categories are responsible for the majority of the total environmental impact of asphalt mixtures. The objective of this study was to identify the impact categories with the greatest contribution to the total environmental impact of hot mix asphalt so that they can be implemented in the form of environmental indicators in GPP. The scope included conventional and polymer-modified binder and three mix design alternatives: only virgin aggregate, reclaimed asphalt pavement (RAP), and RAP with rejuvenators. The cradle-to-cradle life cycle assessment (LCA) performed showed that global warming (GW), fine particulate matter formation, fossil resource scarcity, and human non-carcinogenic toxicity were responsible for at least 90% of the total impact according to the ReCiPe 2016 hierarchic assessment method. Therefore, a simplified LCA focusing on these four impact categories seems sufficient for the purpose of comparing the environmental performance of alternatives in GPP. It was also found that GW alone accounted for approximately 50% of the total impact, which seems to make GW a good surrogate for the total impact among the asphalt mixtures evaluated. Future work should investigate whether the conclusions from this study still hold up when using secondary materials, lower temperature mixing technologies, or in-situ recycling.

Major Building Materials in Terms of Environmental Impact Evaluation of School Buildings in South Korea

This study aimed to analyze the major building materials in terms of environmental impact evaluation of school buildings in South Korea. Three existing school buildings were selected as the analysis targets, and building materials were analyzed in terms of cumulative weight and six environmental impact categories (global warming potential, abiotic depletion potential, acidification potential, eutrophication potential, ozone-layer depletion potential, and photochemical oxidation potential). The materials were analyzed from an environmental perspective after integrating the six environmental impact categories into the environmental costs. From the analysis, nine major building materials, including ready-mixed concrete, concrete bricks, aggregate, rebar, cement, stone, glass, insulating materials, and wood, were selected for the school buildings. These analysis results can be used as a streamlined evaluation of the environmental impacts of school buildings. It is thought that the simplified life cycle assessment will help make decisions considering environmental characteristics in the early stage of the construction project. Additionally, it will be possible to make LCA efficient in terms of time and cost, one of the largest constraints of the existing building LCA, and effective reduction in the environmental load.

Implications of the building system boundary definition to conduct an LCA. A case study comparison of two frameworks for assessing building sustainability: DGNB and Level(s)

The embodied impacts calculation is increasing attention in research, and the use of Life Cycle Assessment (LCA) is the most widely recognised method for that purpose. To support architects and engineers in the use of LCA and to overcome the complexity of calculations in design stage practice, different frameworks for assessing building sustainability propose to conduct simplified LCA methods. Nevertheless, LCA implementation in these frameworks is not completely harmonised, causing problems of inaccuracy and incomplete assessments that generate incomparability among case studies and even possible deviations to achieve carbonneutral scenarios. There, the system boundary definition is a key step. The present paper aimed to illustrate its implications, analysing the implementation of the LCA in a building envelope of a certified passive house located in Italy. Two building sustainability frameworks, DGNB and Level(s), are used to identify how the system boundary definition influences the impact assessment results. The study keeps LCA methodological assumptions (data sources, impact categories, characterisation methods, and indicators) constant to allow a comparison focused on the system boundary implications (such as the modularity principle of LCA). The results show the margins and reduction percentages that can be achieved by the two different assessment frameworks. Finally, limitations and challenges related to methodological aspects in the use of simplified LCA to calculate the impacts of a Passive House building are addressed.