Life Cycle Assessment Analysis Research Articles

Comparative life cycle assessment and techno-economic analysis of electric arc furnace steelmaking processes integrated with solar energy system

Electric arc furnace (EAF) steelmaking process is an environmentally friendly, energy saving, and low-carbon route to produce steel, but its further development is restricted by extensive electricity consumption in China. In this paper, the EAF steelmaking processes driven by solar energy system (EAF-SES) was developed, which supplies electricity for the whole process, and reduce the dependence on traditional energy sources. Life cycle assessment and techno-economic analysis of EAF steelmaking processes integrated with traditional energy system (EAF-TES) and EAF-SES was conducted according to the data of 1536 heats based on the function unit of 1000 kg of molten steel (MS). EAF-SES and EAF-TES were studied and compared from perspectives of life cycle carbon footprint (LCCF), production cost (PC), raw materials cost (RMC), solar energy price (SEP), and carbon tax (CT). The results indicated that EAF-SES enjoyed lower LCCF but higher PC than EAF-TES. The LCCF of EAF-SES was 220 kg lower than that of EAF-TES. Besides, compared to the PC of 478 $ per ton of MS in EAF-TES, the PC in EAF-SES increased by 9.13%. While the electricity price was lower than 0.041 $/kWh or CT higher than 217 $/t CO2, respectively, EAF-SES had both significant advantages of economic and environmental benefits. Vigorously employing clean energy power generation, cutting down hot metal supply, and adopting full scrap melting mode in EAF steelmaking processes achieve better environmental performance. This research is expected to supply a technical idea for energy conservation, emission reduction, and cleaner production in future iron and steel industry.

Opportunities for centralized regional mode of manure and sewage management in pig farming: The evidence from environmental and economic performance

Pig breeding is moving toward more intensive development and is accompanied by the integrated generation of pig waste. This has disrupted the synergy between the original manure and sewage management mode and corresponding farmland at the household level. Centralized bio-energy mode is proposed to relieve environmental pressure, increase the resource recovery efficiency and rebuild the breeding and cropping. However, there is a lack of comprehensive information on a regional scale, particularly regarding evaluation, applicability and feasibility. Therefore, compared to the individual and traditional mode at the household level, this study was conducted using life cycle assessment and life cycle cost analysis, systematically assessed the environmental performance and economic viability of the centralized bio-energy mode at the regional scale, and further explored the adaptability of multi-subjects (various pig farms and biogas enterprise) and regional feasibility. Results revealed that the centralized bio-energy mode appeared to be a better alternative in terms of global warming, terrestrial acidification and marine eutrophication, with the significant reductions of 49.49 %, 6.8 % and 4.67 % respectively. Moreover, the study demonstrated a substantial profit of 48.5 CNY11CNY, Chinese yuan, 1 CNY=0.145 USD (1 April 2023). per ton of managed pig waste. Furthermore, both environmental and economic performance could be improved through scale expansion and transport optimization, with an optimal collection radius of less than 31.45 km. Conclusions clarified the potential of centralized bio-energy mode and provided valuable references for its implementation in various regions. Ultimately, further contributing to a more efficient, cost-effective, and regulated manner for resource recovery, culminating in the sustainability of pig farming and achieving environmental-friendly agriculture practices in regional contexts.

Comparison of the use of life cycle assessment and ecological footprint methods for evaluating environmental performances in dairy production

One popular methodology for assessing the environmental impact of livestock sector is Life Cycle Assessment (LCA), that quantifies the environmental impact of a product. Ecological Footprint (EF) performs an environmental sustainability assessment, by comparing the demand for natural capital by an economic activity with the offer of such capital within a certain territory. The aim of the study was the comparison between LCA and EF in assessing the environmental performances of milk production, assuming as case study three cattle farms with increasing levels of production intensity. Different metrics and functional units (FU) (i.e., fat and protein corrected milk, FPCM and hectare) were adopted for LCA analysis, considering some of the major impact categories. For greenhouse gases emissions, the Global Warming Potential (GWP) and the Global Temperature Potential (GTP) were considered. Both metrics were calculated assuming or not the distinction between biogenic and fossil methane. Adopting GWP as a metric, the results per kg of FPCM provided by the LCA highlighted a different trade off compared to the EF method: the farm with the highest productive intensity produced the least impactful milk in terms of GWP but had the most negative Ecological Balance (EB). The same occurred for the other impact categories. When GTP was adopted, or the hectare was considered as FU, the least intensive farm, characterized by greater feed self-sufficiency, became the one that produced the least impactful milk and had the least negative EB. The study highlighted the scientific significance of the integration between the two approaches for creating a comprehensive representation of the effects of human activities on the environment. The LCA method evaluates impacts intensity referred to a specific functional unit and its results are strongly influenced by productive efficiency; the EF method evaluates environmental sustainability of productions in relation to the territory that supports them.

Thermodynamic and environmental analysis of self-thermal antibiotic residues supercritical water gasification system for hydrogen and power production

Efficient treatment of antibiotic residue, containing a range of persistent organic compounds, is essential to ensure the protection of both the environment and human health. Supercritical water gasification technology could achieve the clean and efficient energy conversion of antibiotic residues. In this paper, a self-thermal supercritical water gasification system for antibiotic residues is developed to convert antibiotic residues to high-purity H2 and electrical power. The system analysis results demonstrate that increasing the antibiotic residue slurry concentration, elevating the gasification reactor temperature, and optimizing the ratio of water-to-dry antibiotic residues effectively enhance system efficiency and H2 yield within specific ranges. The H2 yield and net electrical power at optimal operating conditions are 634.52 kg/h and 2.3 MW with 10 t/h dry antibiotic residue feeding. Meanwhile, the energy efficiency, exergy efficiency, and cold gas efficiency of the system are 61.32%, 63.05%, and 53.96%, respectively. The life cycle assessment analysis shows that the global warming potential of the system is 20.77 kg CO2-eq/kg H2 with the above operating conditions. Taking into account the emission reduction impact of the system on thermal power generation, the inclusion of CO2 capture and storage units can potentially lead to a negative global warming potential for the system.

Integrated life cycle assessment and emergy analysis of liquid dehumidification absorption refrigeration driven by solar energy

The cascade utilization of solar energy is significant in alleviating energy and environmental problems. A novel solar-driven liquid dehumidification cascade absorption refrigeration (SLDAR) system applied to hot summer and cold winter areas of China is proposed in this paper. In order to evaluate the environmental and economic sustainability of the system, an integrating life cycle assessment and emergy analysis (LCA-EmA) method is developed. Parameter sensitivity analysis is conducted to determine the effects of solar radiation intensity, air temperature and relative humidity on the sustainability of the system. The results reveal that the total potential environmental impact of the system is 7.29E+03, of which the construction stage accounted for the most part of 65.36%. The total emergy input of the system is 1.61E+17 sej/yr, the operation stage accounted for the highest proportion of 73.29%. According to the integrated LCA-EmA, the emergy sustainability index of the system is 3.89, which reduces by 29.01% than the result of the emergy analysis. The parameter sensitivity analysis states that the system has higher resource use efficiency and emergy yield ratio in higher solar radiation intensity. And the emergy sustainability index of the system increases first and then decreases as the air temperature increases. The environmental load rate increases by 15.19% and the emergy sustainability index decreases by 44.50% as the increase of relative humidity. This study proves the feasibility and sustainability of the solar-driven cascade system.

Techno-Economic and Life Cycle Assessment of Enhanced Rock Weathering: A Case Study from the Midwestern United States.

Enhanced rock weathering (ERW) is a carbon dioxide removal (CDR) strategy for combating climate change. The CDR potentials of ERW have been assessed at the process and national/global levels, but the environmental and economic implications of ERW have not been fully quantified for U.S. applications with real-world supply chain considerations. This study develops an optimization-based, integrated life cycle assessment and techno-economic analysis framework for ERW, which is demonstrated by a case study applying mining waste to croplands in the Midwestern U.S. The case study explores maximum transportation distances for intermodal transportation at varied mineral CDR yields and costs, informing supply chain design for economically viable ERW. ERW costs (US$45 to 472/tonne of net CO2e captured) and cradle-to-farm gate GHG emissions (41 to 359 kg CO2e/tonne of CO2e captured) are estimated based on a range of CDR yields and by transportation distances to and from two Midwest port destinations: Chicago and Duluth. Our sensitivity analysis identifies CDR yields, and transportation modes and distances as driving factors for result variations. Our study reveals the importance of ERW supply chain design and provides an example of U.S. CDR implementation. Our framework and findings can be applied to other regional ERW projects.

Electrolyzed Hypochlorous Acid (HOCl) Aqueous Solution as Low-Impact and Eco-Friendly Agent for Floor Cleaning and Sanitation.

Recently, the use of disinfectants has been becoming a diffused and sometimes indiscriminate practice of paramount importance to limit the spreading of infections. The control of microbial contamination has now been concentrated on the use of traditional agents (i.e., hypochlorite, ozone). However, their prolonged use can cause potential treats, for both human health and environment. Currently, low-impact but effective biocides that are prepared in a way that avoids waste, with a very low toxicity, and safe and easy to handle and store are strongly needed. In this study, produced electrochemically activated hypochlorous (HOCl) acid solutions are investigated and proposed, integrated in a scrubbing machine for floor cleaning treatment. Such an innovative machine has been used for floor cleaning and sanitation in order to evaluate the microbial charge and organic dirt removal capacity of HOCl in comparison with a machine charged with traditional Ecolabel standard detergent. The potential damage on floor materials has also been investigated by means of Scanning Electron Microscope (SEM). A comparative Life Cycle Assessment (LCA) analysis has been carried out for evaluating the sustainability of the use of the HOCl-based and detergent-based machine.

Recycled Concrete Aggregates (RCA)-based asphalt mixtures: A performance-related evaluation with sustainability-criteria verification

This investigation aims to explore the feasibility of using Recycled Concrete Aggregate (RCA) as a partial replacement for Natural Aggregates (NAs) in the production of Hot Mix Asphalt (HMA) and Warm Mix Asphalt (WMA). As WMA technology, Iterlow T (a chemical additive) was selected. For both types of asphalt mixtures, the RCA dosages of 0, 15, 30 and 45% by weight of coarse aggregates were considered. Notably, four different RCA sources were assessed, and the alkali-silica reaction and attached mortar quantity were analyzed for each one. In order to examine the effect of the coarse RCA on the performance-related properties of the asphalt mixtures, a test protocol was conducted. This protocol comprised four tests, i.e., stiffness modulus, moisture susceptibility, rutting resistance, and fatigue life. Additionality, a sustainability-criteria verification was performed employing the Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) methodologies. Respectively, the LCA and LCCA estimate each alternative's environmental impacts and production costs. Consequently, the main finding obtained were: (i) as the coarse RCA content increases, asphalt mixtures exhibit a reduction in their mechanical performance; (ii) the performance-related properties of the HMAs and WMAs with a 15% RCA dosage are acceptable, but more elevated amounts generate highly noticeable deterioration; and (iii) 15% of coarse RCA minimizes the environmental burdens and maximizes the cost-effectiveness of the asphalt mixtures fabrication. Thus, the main contribution to the literature that achieves this research is to perform a comprehensive multi-criteria examination on the potential of the RCA as a recycled material to minimize the depletion of non-renewable resources.

Constructed wetlands with recycled concrete for wastewater treatment in cold climate: Performance and life cycle assessment

This study investigated the technical, environmental, and economic feasibility of using recycled construction material (concrete) as substrate in constructed wetlands for cold climate decentralized domestic wastewater treatment. The wastewater treatment efficiency was examined, and life cycle assessment (LCA) and cost benefit analysis were performed. The technical feasibility was assessed in lab-scale two-stage wetland systems with recycled concrete or lava stone as substrates, which were operated at 22 °C and 5 °C with local wild plants and vegetables. The wetlands removed ∼85 % and ∼51 % of organics and ∼67 % and ∼34 % TN at 22 °C and 5 °C, respectively; no significant difference was found between concrete and lava stone. The heavy metal contents in the cultivated vegetables met WHO standards for human consumption, showing the feasibility of nutrient recovery from the treated wastewater. A comparative LCA of septic tank standalone, septic tank + constructed wetland (with recycled concrete), and gravity-driven ceramic membrane (GDCM) system was performed. This aims to illustrate the benefits of intensifying the existing treatment process (i.e., septic tank) with the constructed wetland, with an alternative membrane-based treatment technique as benchmark. The LCA results revealed that using waste materials as the substrate in constructed wetlands could reduce the environmental impact of wetlands. Installation of the wetland as posttreatment of the septic tank (1) could reduce ∼50 % of eutrophication potential without increasing global warming impact compared to the septic tank alone; (2) had ∼90 % higher global warming impact and ∼40 % lower eutrophication impact compared to GDCM. Economic analysis revealed that the total cost of septic tank + constructed wetland (0.143 €/m3) was comparable to the septic tank alone (merely 3.5 % difference), and 49 % lower than that of GDCM (with recycled membranes). Therefore, the septic tank + constructed wetland scenario could be favorable for sensitive areas with eutrophication potential regarding its technical, economical, and environmental feasibility.

Electrospun nanofibrous membranes for membrane distillation application-A dynamic life cycle assessment (dLCA) approach.

Membrane distillation (MD) for water desalination and purification has been gaining prominence to address the issues relating to water security and the destruction of aquatic ecosystems globally. Recent advances in electrospun membranes for MD application have improved antifouling and anti-wetting performance. However, the environmental impacts associated with producing novel electrospun membranes still need to be clarified. It is imperative to quantify and analyze the tradeoffs between membrane performance and impacts at the early stages of research on these novel membranes. Life Cycle Assessment(LCA) is an appropriate tool to systematically account for environmental performance, all the way from raw material extraction to the disposal of any product, process, or technology. The inherent lack of detailed datasets for emerging technologies contributes to significant uncertainties, making the adoption of traditional LCA challenging. A dynamic LCA (dLCA) is performed to guide the sustainable design and selection of emerging electrospun poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) electrospun membrane (E-PH) and hybridizing polydimethylsiloxane (PDMS) on E-PH membrane (E-PDMS) for dyeing wastewater treatment technologies. The associated environmental impacts are related to the high energy demands required for fabricating electrospun nanofibrous membranes. After LCA analysis, the E-PDMS membrane emerges as a promising membrane, due to the relatively low impact/benefit ratio and the high performance achieved in treating dyeing wastewater.

Parametric BIM-based life cycle assessment framework for optimal sustainable design

The construction sector is liable for a sizable amount of CO2 emissions and waste. Life Cycle Assessment (LCA) is considered one of the crucial tools that aids in evaluating the impacts of construction emissions. This research aims to quantify the life cycle impacts of the initial and recurrent embodied emissions, operating and reuse/disposal emissions, and utilizing Building Information Modeling (BIM) for a more holistic life cycle approach. The research proposes a parametric BIM-based LCA framework for quantifying the environmental impacts and evaluating the effects of material selection for both embodied and operating emissions. In addition, it considers the different reuse scenarios and percentages and their effect on both the embodied and operating impacts. The proposed framework consists of five main modules: data acquisition module, operating and embodied emissions module, life cycle assessment module, optimization module, and decision-making module. This parametric assessment can be applied for both the conventional and circular approach impacts. For the decision-making process, the resulting emissions are optimized utilizing the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and evaluated through an LCA and Data Envelopment Analysis (DEA) methodology for the material selection. A case study of a residential villa in Cairo is worked out to illustrate the key features of the proposed framework. This assessment analyzes the building materials’ characteristics and efficiency investigating the external walls, internal walls, floors, roofs, and windows design possibilities, and uses visual programming to control the resulting emissions for a more flexible approach. By comparing the integrated LCA and DEA models three optimum design solutions, the conventional approach develops design solutions of higher embodied Global Warming Potential (GWP) than the circular approach. However, it develops lower operating GWP with better applied U-values. The circularity approach employment has reduced the efficiency of the operating GWP due to utilizing materials with high heat transmittance ability.

Comparative Study of The Life Cycle Assessment Model for Agricultural Solid Waste Management: Case Studies in East Ungaran and West Ungaran Districts, Semarang

The increase in population affects the production of available food; this also increases agricultural activities and the waste produced. Improper agricultural waste management harms the environment, so a good agricultural waste management strategy is needed. The areas that are the object of study are East Ungaran and West Ungaran Districts, Semarang Regency. This area has great potential in the agricultural sector. This plan aims to analyze the existing conditions, volume, and mass balance of agricultural waste and their environmental impact using the life cycle assessment (LCA) and material flow analysis (MFA) methods to determine the appropriate strategy for managing agricultural solid waste. It is planned to manage agricultural solid waste using two alternative solutions, which are then compared using the LCA method using the SimaPro application and the Analytical Hierarchy Process (AHP) method involving two experts in the agricultural sector. Based on the analysis, processing agricultural solid waste as bokashi fertilizer and silage livestock feed is the most suitable method and is of interest to farmers.

Life cycle assessment and life cycle cost analysis of anion exchange and granular activated carbon systems for remediation of groundwater contaminated by per- and polyfluoroalkyl substances (PFASs).

Anion exchange resin (AER) and granular activated carbon (GAC) have emerged as prominent technologies for treatment of waters contaminated with per- and polyfluoroalkyl substances (PFASs). This study compares the life cycle environmental impacts and life cycle costs of remediating PFAS-contaminated groundwater with these competing technologies, using field pilot data to inform model inputs. Comparative analysis indicates that AER systems employing single-use "PFAS-selective" resins have lower environmental impacts and costs than systems using regenerable resins or GAC adsorbents, supporting its use in future remediation efforts. Use of GAC operated as a single-use adsorbent led to the highest emissions as well as the highest treatment costs, with thermally-reactivated GAC proving to be less impactful than regenerable AER treatment. Sensitivity analyses highlighted the dominance of media usage rate (MUR), which is highly dependent on the selected PFAS treatment goals, to determine environmental impacts and costs over a 30-year system life cycle. Selection of very stringent changeout criteria (e.g., detection of any PFASs in effluent) significantly reduces the advantages of single-use resins. For regenerable AER, environmental impacts were dominated by management of the PFAS-contaminated brine/co-solvent waste stream used to regenerate the adsorbent, as well as the cosolvent content of the regenerant mixture and the cosolvent recovery efficiency achieved via on-site distillation. High impacts estimated for GAC adsorption, the result of high MUR relative to ion exchange media, can be significantly reduced if spent adsorbents are reused after thermal reactivation, but impacts are still greater than those predicted for single-use ion exchange systems. Findings are expected to hold across a range of diverse sites, including drinking water systems treating more dilute sources of PFAS contamination, as PFAS breakthrough was not found to be highly sensitive to sourcewater PFAS concentrations.

Effect of realistically estimated building lifespan on life cycle assessment: A case study in Korea

In the construction industry, estimating the realistic lifespan of buildings is essential to properly perform life cycle assessments (LCAs). It is impractical to consider all of the different factors affecting building lifespan; therefore, most LCAs assume a standard building lifespan for each major type of building structure. However, the lifespans of buildings vary significantly in practice, and applying a uniform lifespan to all buildings with the same structural type may lead to completely erroneous LCA results. In this study, LCAs of waterproofing methods on building models and actual buildings in Korea are used to empirically demonstrate the effect of realistic lifespan prediction using big data. Applying a more representative building lifespan of 5–39 years in the waterproofing LCAs of an architectural model decreased the carbon emissions in all phases (construction, operation and maintenance, and demolition) by 78–24%, respectively, relative to a 50-year lifespan assumption. During the maintenance phase, the reductions were 100–31%, respectively. The accuracy of the waterproofing LCAs of 17 real buildings became more irregular as the percentage error of the predicted lifespan increased, although the LCA analysis results had 0% error for buildings with a predicted lifespan error of 6% or less. Therefore, depending on the research purpose, a low-error predictive building lifespan model can evidently support accurate LCA results. This study proves that the use of a big data-based building lifespan prediction method is essential for LCA and is an effective tool for business planning and critical decision-making throughout the construction process.

Lignin valorisation: Life Cycle Assessment (LCA) considerations for enabling Circular Bioeconomy

ABSTRACT Lignin constitutes the sole renewable aromatic resource found in abundance on Earth and does not call into question the ethics of diverting land from food to energy production. In view of that, the potential of lignocellulosic biomass in promoting the Circular Economy and Bioeconomy concepts in future biorefinery operations is widely acknowledged. Biorefineries can convert lignocellulosic biomass into high-value products, lessen their environmental effect, and hasten the advent of a sustainable and renewable future by incorporating cutting-edge technologies and doing thorough Life Cycle Assessment analysis. However, converting lignin into added-value products is a challenging field from technological, environmental, and economic perspectives. This work set out to determine the most critical environmental aspects expected to provide reliable evidence in support of lignin valorisation routes that enable the production of value-added products and bioenergy. Findings provide the necessary knowledge for decision-making in biorefineries aligned with the Circular Bioeconomy concept, like how decision-making relating to future biorefineries is facilitated. Highlights Environmental burdens of lignin-derived products valorisation due to complex lignin structure A limited number of LCA studies on the valorisation of lignin to added-value products Future lignin-based biorefineries development should be assessed using holistic, sustainable approaches LCA methodologies on environmental performance of promising lignin valorisation routes Controversial aspects of lignin valorisation under the Circular Bioeconomy concept Raised concerns as a result of the lignin fraction expected high demand Identified controversial environmental aspects linking lignin valorisation to adverse impacts

Sustainable and Cost-Effective Bio-Waste-Derived Hard Carbon Synthesis for Sodium-Ion Batteries

The commercialization of sodium-ion batteries (SIBs) is around the corner to support on electrification of various applications, especially focused on light electromobility and stationary applications. The anode of choice in SIBs is hard carbon (HC) following the success story of graphite anode in lithium-ion batteries. [1-4] One of the greatest advantages of HC is that the bio-waste precursor can be used, enhancing sustainability and provides cheap material price from its abundance. However, bio-waste HC often undergoes a strong acidic/basic pre-/post-treatment for removing impurities and increasing carbon yield but decreases initial Coulombic efficiency (ICE) and total sodium uptake in turn. [5,6] We attempted to find a more sustainable solvent to replace the traditional method for such HCs. In this work, the morphology, microstructure, and electrochemical performance characteristics of hazelnut shells-derived HCs were investigated when processed in different pre-treatment agents (i.e., no pre-treatment, acid treatment, and water washing). [7] The results reveal that hazelnut shell derived-HCs produced via facile and sustainable water washing outperform those obtained via other processing methods in terms of ICE, capacity uptake and retention. Moreover, the applicability of the hazelnut shell-derived HC is demonstrated in a sodium-ion full-cell. Finally, the cost-ecological effectiveness of sustainably processed HC compared to acid processed one was investigated and confirmed by life cycle assessment (LCA) and cost analysis.[1] CATL, “CATL Unveils Its Latest Breakthrough Technology by Releasing Its First Generation of Sodium-ion Batteries,” 2021.[2] L. Cailloce, https://newscnrsfr/articles/a-battery-revolution-in-motion 2015.[3] S. Kuze, J. Kageura, S. Matsimoto, T. Nakayama, M. Makidera, M. Saka, T. Yamaguchi, T. Yamamoto, K. Nakane, R&D Report 2013, 1–13.[4] A. Rudola, A. J. R. Rennie, R. Heap, S. S. Meysami, A. Lowbridge, F. Mazzali, R. Sayers, C. J. Wright, J. Barker, Journal of Materials Chemistry A 2021, 9, 8279–8302.[5] S. Ghosh, R. Santhosh, S. Jeniffer, V. Raghavan, G. Jacob, K. Nanaji, P. Kollu, S. K. Jeong, A. N. Grace, Sci. Rep. 2019, 9, 16315.[6] K. L. Hong, L. Qie, R. Zeng, Z. Q. Yi, W. Zhang, D. Wang, W. Yin, C. Wu, Q. J. Fan, W. X. Zhang, Y. H. Huang, Journal of Materials Chemistry A 2014, 2, 12733–12738.[7] H. Moon, A. Innocenti, H. Liu, H. Zhang, M. Weil, M. Zarrabeitia, S. Passerini, ChemSusChem 2022 DOI: 10.1002/cssc.202201713

Carbon Emission Evaluation of Roadway Construction at Contaminated Sites Based on Life Cycle Assessment Method

Greenhouse gas emissions induced by climate change have garnered global attention. Minimizing climate change can be achieved through the reduction of carbon emissions in transportation infrastructure construction and in the production of construction materials. This study aims to calculate carbon emissions in three hypothetical construction scenarios based on the life cycle assessment (LCA) method when a roadway passes across polluted soil at contaminated sites. Three methods are employed to remediate contaminated soil: off-site cement kiln co-processing, on-site ex-situ thermal desorption, and on-site ex-situ solidification/stabilization. Carbon emissions are calculated using the LCA method for each scenario. The baseline carbon emission is estimated for the scenario in which contaminated soil is remediated using the off-site cement kiln co-processing method, and the roadway subgrade is constructed using transported clean soil. In the other two scenarios, contaminated soils are remediated using the on-site ex-situ thermal desorption and solidification/stabilization methods, respectively, and then they are reused as roadway subgrade materials. The LCA analyses demonstrate that the total carbon emission reductions range from 1168.48 to 2379.62 tons per basic unit, corresponding to decreased of 19.31% to 39.33%, respectively, compared to baseline. The reuse of solid waste to replace sand and ordinary Portland cement (OPC) as raw materials in roadway construction reduces carbon emissions by 498.98 tons. Finally, a comparison of carbon emissions between the three scenarios indicates that reducing carbon emissions in the remediation of contaminated soil and reusing solid waste as construction materials are two important methods for achieving overall carbon emission reductions in roadway construction projects.

Molecular catalysed Guerbet reaction: Moving to the larger and the Greener through LCA and scale up simulation approaches

Efficient homologation of bio-ethanol can be performed under mild conditions exploiting a catalytic system based of a ruthenium molecular catalyst, benzoquinone and a base as a co-catalysts. Conversions and selectivity can be tuned by changing the head space of the reactor. On this basis, preliminary design of a full-scale process has been developed based on the experimental results. The process has been characterized with specific energy and performance indicators per unit of produced butanol, which have been used as input for the life cycle assessment analysis. The LCA was applied as scientific methodology to address potential burdens of the baseline configuration, 3X catalytic cycles, electricity from Italian grid and heat from natural gas. Hotspots were identified according to a multi-impact approach method (ReCiPe 2016). The usage of dedicated lignocellulosic biomass as a source of EtOH, the synthesis of the catalytic system and the energy requirements were addressed as the major contributors. Thus, further sensitivity scenarios were created. The best configuration was identified in the use of waste biomasses and in an integrated cogeneration unit. In addition, enabling the recovery of the catalytic system up to five cycles to scenario shows a reduction in the impacts higher than 50% for the categories of global warming potential, −41% for the mineral resource scarcity and around −16% for the fine particulate matter formation. The results were also confirmed by an uncertainty analysis with the Monte Carlo method, which demonstrated the major environmental sustainability of the Guerbet route compared to the oxo synthesis from propylene.

Comparative Life Cycle Assessment and Exergy Analysis of Coal‐ and Natural Gas‐Based Ammonia Production

AbstractA comprehensive life cycle assessment (LCA) analysis of ammonia production is presented, focusing on the comparison between natural gas‐based and coal‐based processes. Ammonia production is associated with high energy consumption and significant carbon dioxide (CO2) emissions. The objective of this research is to identify key processes and parameters within the ammonia synthesis industry and provide recommendations for cleaner and more sustainable development. Exergy analysis is performed to assess the efficiency of ammonia production technologies and determine optimal operating conditions. Natural gas‐based ammonia production has lower environmental impacts compared to coal‐based production in most categories, except for ionizing radiation. Natural gas, being a cleaner‐burning fossil fuel, produces fewer greenhouse gas emissions and other air pollutants. However, it is essential to address the issue of ionizing radiation in natural gas‐based processes. The potential for more efficient technologies and the importance of removing sulfur and other impurities during the production process to optimize catalyst performance are highlighted.

Precision nitrogen management in rainfed durum wheat cultivation: exploring synergies and trade-offs via energy analysis, life cycle assessment, and monetization

Fertilization with variable rate technology (VRT) is a pivotal technique of precision agriculture proposed for eco-friendly farming practices. Yet the magnitude of environmental benefits is often not well known or is highly variable. This study used a multi-indicator model and life cycle-based indicators to compare the performance of rain-fed durum wheat production using uniform (UA) and variable N fertilization (VRT). Two functional units were used: 1 ha of cultivated wheat and 1 ton of wheat produced. The energy analysis indicated that VRT increases energy use efficiency and productivity by 13.3%, reduces specific energy and total energy input by 11.7%, and increases net energy gain by 15.3%. The life cycle assessment (LCA) analysis indicated that for some environmental impacts, VRT had minor negative effects due to the comparable yield performance with UA. Yet, the VRT had a noteworthy positive impact on global warming, fine particulate matter formation, stratospheric ozone depletion, terrestrial acidification, and marine eutrophication, generating a final environmental benefit of 12.2% for 1 ton of product and 13.3% for 1 ha of land. Economic valuation or monetization of LCA results using monetization weighting factors indicated indirect economic benefits of VRT can be up to 6.6% for 1 ton of product and 7.7% for 1 ha of land. Our findings support the use of nitrogen fertilization with VRT for sustainable extensification and improved eco-efficiency of wheat production in a Mediterranean context. As a result of our research, we conclude that future case studies on annual crops with moderate land requirements should employ multiple metrics and functional units, as well as the concepts of monetization and life cycle assessment, to investigate trade-offs between yield, economic, and environmental benefits and to aid decision-making about the true sustainability of proposed farming technologies.Graphical abstract