This study conducts a comprehensive life cycle assessment (LCA) on converting waste vehicle tyres into recycled crumb rubber (CR) granules as an alternative polymer for enhancing asphalt properties. ...The LCA study has been performed on acquired industrial primary data by incorporating CR at different proportions of binder in one ton (1-ton) of asphalt mix following the wet method. The uncertainty analysis of design variables identified a relatively strong positive relation of emissions with the equipment energy consumption (r = 0.98). Monte Carlo simulations evaluate the potential renewable sources (solar, hydro, and wind) in sequence over fossil fuels for the possible transition in the Australian grid by 2030 and 2050, as per the Paris Agreement. 71.91% reduction of CO2 emissions is achievable by recycling vehicle tyres into crumb rubber compared to landfill and incineration. Recycling by-products of CR production, such as steel and textile, significantly mitigates negative impacts. A decrease of 2.23% emissions was associated to the use of crumb rubber as a binder modifier in the asphalt mixture via the midpoint assessment. In endpoint LCA, a higher association of resource (US$) saving costs was observed than for other protective zones, i.e., human health and ecosystem damage. Recycling 466,000 tonnes of disposable waste tyres contributes to 16.1 million US$ worth of resource savings. An equitable industry-based LCA and uncertainty analysis of design parameters can assist in prioritizing suitable options to improve efficiency and future emission strategies on a global scale.
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•LCA is conducted on waste vehicle tyres using primary data from the recycling facility.•Recycling waste tyres into CR reduces CO2 emissions by 71.91% compared to landfills.•A 2.23% decrease in emission is achievable by adding 20% CR as bitumen modifier.•Transitioning to a solar source to recycle tyres lower the total environmental impacts.•Recycling waste tyres can save up to US$16.1 million resources worth annually in Australia.
Brazil has always been the pioneer in the application of bioethanol as a main fuel for automobiles, hence environmental and economic analyses of the Brazilian ethanol industries are of crucial ...importance. This study presents a comparative life cycle assessment (LCA) on gasoline and ethanol as fuels, and with two types of blends of gasoline with bioethanol, all used in a midsize car. The focus is on a main application in Brazil, sugarcane based ethanol. The results of two cases are presented: base case—bioethanol production from sugarcane and electricity generation from bagasse; future case—bioethanol production from both sugarcane and bagasse and electricity generation from wastes. In both cases sugar is co-produced. The life cycles of fuels include gasoline production, agricultural production of sugarcane, ethanol production, sugar and electricity co-production, blending ethanol with gasoline to produce E10 (10% of ethanol) and E85 (85%), and finally the use of gasoline, E10, E85 and pure ethanol. Furthermore, a life cycle costing (LCC) was conducted to give an indication on fuel economy in both cases. The results show that in the base case less GHG is emitted; while the overall evaluation of these fuel options depends on the importance attached to different impacts. The future case is certainly more economically attractive, which has been the driving force for development in the ethanol industry in Brazil. Nevertheless, the outcomes depend very much on the assumed price for crude oil. In LCC a steady-state cost model was used and only the production cost was taken into account. In the real market the prices of fuels are very much dependent on the taxes and subsidies. Technological development can help in lowering both the environmental impact and the prices of the ethanol fuels.
This study presents a comparative life cycle assessment (LCA) of traditional and emerging treatment approaches for hazardous refinery oily sludge handling. Two traditional oily sludge disposal ...approaches, including incineration and landfilling, and two emerging energy recovery approaches, including solvent extraction and pyrolysis, were investigated. Life cycle inventories listing all energy and material flows were established for the two emerging treatment approaches, and the life cycle environmental impacts were assessed by following the International Organization for Standardization (ISO) 14040 procedure. The TRACI 2.1 method and Ecoinvent 3 database were used in the LCA. The results show that the two emerging energy recovery approaches only account for <10% of the total impacts posed by the traditional alternatives. Traditional oily sludge treatment approaches are generally associated with relatively high global warming potential, ecotoxicity, and adverse human health effects. Solvent extraction has the lowest total effect on the environment, and the main adverse effects are related to ecotoxicity and fossil fuel depletion. In solvent extraction treatment, vacuum distillation and combustion of recovered oil account for the main impacts. In pyrolysis treatment, processes such as drying, pyrolysis, and combustion of pyrolysis products are the main contributors to the total impact. The energy recovery processes used in the two emerging approaches can significantly offset the total adverse impacts. The two energy recovery approaches have great potential to be used for low-impact oily sludge treatment.
Six alternatives for the conversion of an average Colombian palm oil mill (30 t h−1 of fresh fruit bunches (FFB) into biorefineries were evaluated. The alternatives studied were: (C1) Production of ...biogas from the Palm Oil Mill Effluents (POME), (C2) Composting of empty fruit bunches (EFB) and fiber, (C3) Biomass combustion for high pressure steam combined heat and power, (C4) Pellets production, (C5) Biochar production and, (C6) Biochar and bio-oil production. The available biomass could result in up to 125 kWh of electricity, 207 kg of compost, 125 kg of pellet, 44 kg of biochar and 63 kg of bio-oil per metric ton of FFB. The global warming potential (GWP), eutrophication potential (EP), net energy ratio (NER), capital expenditures (CAPEX), operational costs (OPEX), net present value (NPV) and internal rate of return (IRR) were calculated for all the alternatives. GHG reductions of more than 33% could be achieved. Anaerobic digestion and composting contributed to 30% reduction of the EP. The CAPEX for all of the biorefinery alternatives studied varies between 0.7 $ t−1 and 2.8 $ t−1 of FFB. The OPEX varies between 1.6 $ t−1 and 7.3 $ t−1 of FFB. The NPV for viable scenarios ranged between 2.5 million and 13.9 million US dollars. The IRR calculated varied between 3% and 56% and the payback periods were between 3 and 8 years. The total extra incomes reached values up to 15.2 $ t−1 of FFB. Overall the pellets production biorefinery was the preferred alternative.
•Six biorefinery concepts were compared using a systematic methodology.•Technical, economic and environmental indicators were used in a decision matrix.•Biogas from POME and pellets production from solid residues have the best economic performance.•The production of biochar and heat is the option with the best environmental performance.•Compared with the baseline case, reductions of GHG emissions from 33 to 100% are achievable.
Sustainable tourism should be promoted as a new system for the sustainable management of resources from a socioeconomic and environmental point of view. For this purpose, it is necessary to develop a ...tool capable of assessing the impacts associated with the sector and to identify which actions are currently being addressed in order to achieve the desired sustainability.
This timely study aims to describe the current framework of Life Cycle Assessment (LCA) and its application to the tourism sector. To address these questions, a total of 83 documents (77 reviews and 6 international reports) were evaluated, assessing the geographical distribution, the temporal evolution of the publications, as well as the most relevant characteristics of the tourism industry articles were evaluated such as, life cycle inventory (LCI), system boundaries, functional unit (FU), methods, environmental indicators and impact categories considered.
The study identifies key recommendations on the progression of LCA in tourism sector. As important results, it stands out that 94 % of articles were from the last decade and 21 % of the articles reviewed cover sustainable tourism term, considering the three dimensions. This review showed that in LCA studies the most common method was CML 2001; the most widely used environmental indicator was the Carbon Footprint (CF) and the Global Warming Potential (GWP) was the impact category used in all the studies. Hence, LCA is a highly effective tool capable of assessing direct and indirect carbon emissions in tourism as well as the socioeconomic and environmental impacts generated in this sector.
COVID-19 pandemic is also an object of discussion in the framework of the sustainable tourism together with advocating support for the eco-labelling and digitalisation of the tourism experiences as valuable tools to minimize environmental negativities, to promote mechanisms to access green markets and to frame successful synergies.
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•The review dissects 77 articles about tourism, 94 % of them over the last decade and 21 % concerning sustainable tourism.•Mapping, time evolution, and characterization of the studies is assessed.•Life Cycle Assessment (LCA) is key to climate change mitigation, tourism sustainability and resilience post-pandemic.•The most common environmental indicator in the LCA methodology is the Carbon Footprint (CF).•Ecolabels and digitalisation strategies are useful for decision-making in the sustainable tourism.
The climate change and soil degradation are among the most prominent environmental issues of today and solutions need to be looked for. Pyrolysis of (waste) biomass to produce biochar that is then ...applied to agricultural soil could be one of the means to tackle these problems. Many authors have used the Life Cycle Assessment method to evaluate the environmental impact of biochar-to-soil projects and in this paper those studies are systematically reviewed to uncover the overall trend. Although the differences in the contexts and characteristics of these studies disallow direct comparison of results, it is still obvious that the application of biochar brings significant benefits, either to neutralize the greenhouse gas emission of agricultural production or as a carbon capture method. There is also a great potential for energy production by utilizing the co-products - syngas and bio-oil. The benefits of carbon sequestration in biochar and the energy production usually overcompensate the greenhouse gas emissions produced during feedstock production and handling. However, the effect on other impact categories needs to be evaluated and limited and the economic sustainability of the project needs to be assured. To facilitate future progress, some methodology unification would be beneficial.
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•Direct comparison of biochar benefits is impossible due to methodology differences.•Methodology unification in the LCAs would facilitate biochar projects.•Biochar application to soil brings significant benefits from a GHG perspective.•Carbon sequestration in biochar is the main beneficial process.•Biochar is also perspective for other means of application.
Micropollutants have been linked to freshwater and human toxicity. Their occurrence in water bodies arises from different causes, including the discharge of effluents from conventional urban ...wastewater treatment plants, which are not designed for their removal. The addition of an advanced treatment process for this purpose will allow a toxicity reduction; however, such will also imply further resources and energy use resulting in other environmental impacts. Energy use is a particularly relevant hotspot of the environmental impacts associated with advanced treatments; therefore, solar-based treatments have great potential in this field. The present study assessed the environmental impacts via life cycle assessment (LCA) of five solar-based treatments – solar photolysis (with and without H2O2), photocatalysis using TiO2 (with and without H2O2) and circumneutral photo-Fenton – using a pilot-scale compound parabolic collector photoreactor to select the most suitable option for the removal of micropollutants (carbamazepine, diclofenac and sulfamethoxazole; 5 μg/L) from a secondary-treated wastewater. The ranking of solar treatments per highest generated impacts is, overall, as follows: circumneutral photo-Fenton > TiO2-P25/H2O2 > TiO2-P25 > solar/H2O2 > solar. While solar photolysis uses fewer resources and energy, thus generating lower environmental impacts, the common incomplete mineralization of the parent micropollutants implies that toxicity reduction cannot be guaranteed in this case. Aiming for a balance between ecotoxicity reduction and the impacts caused by the application of each technology, the solar TiO2-P25 treatment, which was here investigated by LCA for the first time to remove organic micropollutants from secondary-treated urban wastewater, appears to be the most suitable option at the studied conditions (and when TiO2 is reused at least 5 times). One of the environmental downfalls of the assessed treatments is the energy required to produce the chemicals, and so the importance of minimizing external energy use during the application of advanced treatment processes is reinforced.
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•First LCA of solar TiO2 mediated photocatalysis applied to urban wastewater.•Energy for producing reagents is the main hotspot of solar advanced treatments.•TiO2-P25 shows promising results, depending on the number of TiO2 reuses.•If opting for TiO2 photocatalysis, H2O2 use is not recommended in this case.•The downfall of photo-Fenton is the need for acidification.
This review summarizes and organizes the literature on life cycle assessment (LCA), life cycle energy analysis (LCEA) and life cycle cost analysis (LCCA) studies carried out for environmental ...evaluation of buildings and building related industry and sector (including construction products, construction systems, buildings, and civil engineering constructions). The review shows that most LCA and LCEA are carried out in what is shown as “exemplary buildings”, that is, buildings that have been designed and constructed as low energy buildings, but there are very few studies on “traditional buildings”, that is, buildings such as those mostly found in our cities. Similarly, most studies are carried out in urban areas, while rural areas are not well represented in the literature. Finally, studies are not equally distributed around the world.
•Life cycle assessment for sustainable earthquake-resistant construction.•Recycling waste tire rubber and PU-coated tire rubber for building foundations.•RuC as a sustainable alternative to ...conventional concrete foundations.•153.50 MJ/m3 energy conservation in the case of RSM-30 % layer.•227.12 MJ/m3 energy, 134.76 kg CO2 eq/m3 conservation in the case of PUcR-30 %.
Traditional construction practices consume significant energy, emit carbon, and generate waste—prompting a shift towards sustainable earthquake-resistant systems. Nonetheless, a comprehensive life cycle assessment (LCA) of such systems remains scarce. This research bridges the gap by evaluating the environmental impact of repurposing waste tire rubber and polyurethane-coated rubber (PUcR) for cost-efficient seismic isolation. To this aim, a comparative LCA of conventional concrete slabs, natural soil foundations, rubberized concrete (RuC) slabs, rubber-soil layers, and PUcR-soil layers revealed key insights. Firstly, RuC is proven to be more sustainable than conventional concrete. Secondly, integrating 30 % recycled tire rubber in the foundation soil cut energy use by 153.50 MJ/m3 and carbon emissions by 30.75 kg CO2 eq/m3. Thirdly, incorporating 30 % waste PUcR in the foundation soil preserved 227.12 MJ/m3 energy and slashed emissions by 134.76 kg CO2 eq/m3. This underscores the significance of sustainable earthquake-resistant construction approaches and LCA-driven decision-making to bolster conservation and recycling endeavors.
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•Life-cycle analyses of wind in grids have many significant shortcomings today.•Wind displaces far less emissions than typically assessed today.•Wind does reduce emissions but insufficiently to ...qualify as sustainable.•Policy must focus on developing low carbon dispatchable energy sources.•Policy must focus on systemic sustainability and less on renewable energy per se.
Ensuring access to affordable, reliable, sustainable and modern energy for all is one of the Sustainable Development Goals. Some countries have therefore invested significantly in wind energy, but emissions, which is a common measure for sustainability in this context, have not fallen significantly. Reductions between 20% and 40% are typical. We therefore test the hypothesis that wind energy reduces emissions compared to using gas turbines when life-cycle emissions are included. The Irish grid is studied due to its record-high wind penetration. The model is based on high resolution grid data covering four years and input from 828 Life-Cycle Assessment cases to allow detailed analysis of demand, supply, life-cycle emissions and their changes due to the increased ramping of gas turbines and increased grid reserves required to maintain grid reliability when wind is deployed. Indirect effects are included to some extent. The model is sampled 10,000 times using Monte Carlo simulations. The results show that emissions are reduced by 10–20%, which supports the hypothesis. However, with an average wind penetration of 34% in 2019, reaching many times the 65% limit for non-synchronous generation set by the system operator to maintain grid reliability, such modest reductions logically imply that achieving an affordable, low-carbon grid using wind together with fossil energy balancing is infeasible with today’s technology, emissions and costs. This key finding is transferable to other grids where wind has large penetration and requires fossil energy balancing. Thus, wind energy is not sustainable when balanced by fossil fuel generators.
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