The growing production of green technologies (such as electric vehicles and systems for renewable electricity production, e.g., wind turbine) is increasing the rare earth element (REE) demands. These metals are considered critical for Europe for their economic relevance and the supply risk. The end-of-life permanent magnets are considered a potential secondary resource of REEs thanks to their content of neodymium (Nd), praseodymium (Pr) or dysprosium (Dy). The scientific literature reports many techniques for permanent magnet recovery. This work used a life cycle assessment (LCA) to identify the most sustainable choice, suggesting the possible improvements to reduce the environmental load. Three different processes are considered: two hydrometallurgical treatments (the first one with HCl and the other one with solid-state chlorination), and a pyrometallurgical technique. The present paper aims to push the stakeholders towards the implementation of sustainable processes for end-of-life... [more]

Plastics are used for various applications, including in the food and beverage industry, for the manufacturing of plastic utensils and straws. The higher utilization of plastic straws has indirectly resulted in the significant disposal of plastic waste, which has become a serious environmental issue. Alternatively, bio-plastic and paper straws have been introduced to reduce plastic waste. However, limited studies are available on the environmental assessment of drinking straws. Life cycle assessment (LCA) studies for bio-plastic and paper straws have not been comprehensively performed previously. Therefore, the impact of both bio-plastic and paper straws on the environment are quantified and compared in this study. Parameters, such as the global warming potential (GWP), acidification potential (AP) and eutrophication potential (EP), were evaluated. The input−output data of the bio-plastic and paper straws processes from a gate-to-grave analysis were obtained from the literature and gen... [more]

This study verified the environmental effectiveness of potentially less aggressive routes for the synthesis of poly(propylene/ethylene oxide) glycol (PPG). The analysis was developed in two stages. Firstly, the environmental performance of the conventional PPG processing route was compared to alternative variants—vegetal PPG and CO2-based PPG—applying the life cycle assessment technique to measure the primary energy demand, global warming potential, acidification, photochemical oxidation, and freshwater ecotoxicity impact categories. The synthesis of vegetable polyols from bio-based assets, such as vegetable oils, and the application of CO2 conversion routes as an alternative to technologies supported by petroleum and natural gas were studied. The use of CO2 recovered through carbon capture and usage practices resulted in environmental gains for PPG production. The processing routes within vegetal assets were not an environmentally attractive option as the performance was worse than th... [more]

Bioethanol has many environmental and practical benefits as a transportation fuel. It is one of the best alternatives to replace fossil fuels due to its liquid nature, which is similar to the gasoline and diesel fuels traditionally used in transportation. In addition, bioethanol production technology has the capacity for negative carbon emissions, which is vital for solving the current global warming dilemma. However, conventional bioethanol production takes place based on an inland site and relies on freshwater and edible crops (or land suitable for edible crop production) for production, which has led to the food vs. fuel debate. Establishing a coastal marine biorefinery (CMB) system for bioethanol production that is based on coastal sites and relies on marine resources (seawater, marine biomass and marine yeast) could be the ultimate solution. In this paper, we aim to evaluate the environmental impact of using seawater for bioethanol production at coastal locations as a step toward... [more]

Industries are nowadays not only expected to produce goods and provide services, but also to do this sustainably. What qualifies a company as sustainable implies that its activities must be defined according to the social and ecological responsibilities that are meant to protect the society and the environment in which they operate. From now on, it will be necessary to consider and measure the impact of industrial activities on the environment, and to do so, one key parameter is the carbon footprint. This paper demonstrates the utility of the LCI as a tool for immediate application in industries. Its application shall facilitate decision making in industries while choosing amongst different scenarios to industrialize a certain product with the lowest environmental impact possible. To achieve this, the carbon footprint of a given product was calculated by applying the LCI method to several scenarios that differed from each other only in the supply-chain model. As a result of this LCI ca... [more]

Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, there is increasing interest to produce non-soybean, plant-based oils including, but not limited to, coconut, flaxseed and hemp seed. Expeller pressing and organic solvent extractions are common methods for oil extraction in the food industry. However, these two methods come with some concerns, such as lower yields for expeller pressing and environmental concerns for organic solvents. Meanwhile, supercritical CO2 and enzyme-assisted extractions are recognized as green alternatives, but their practicality and economic feasibility are questioned. Finding the right balance between oil extraction and phytochemical yields and environmental and economic impacts is challenging. This review explores the advantages and disadvant... [more]

This study presents a combined process modeling—Life Cycle Assessment (LCA) approach for the evaluation of green Cr2O3 ceramic pigments production. Pigment production is associated with high calcination temperatures, achieved through the combustion of fossil fuels. Therefore, it is necessary to evaluate its environmental impact with regards to energy requirements and CO2 emissions. Initially, a process model is developed to simulate the final calcination stage of the traditional pigments production process. It is validated against titanium dioxide (TiO2) white production industrial data and adjusted for Cr2O3 production. Three alternative processes are examined: two for pigment grade (PIGM1, PIGM2) and one for metallurgical (MET) Cr2O3. Heat demand and CO2 emissions computed by the developed process models are used as input in the LCA along with upstream data from the literature using a cradle-to-gate approach. The implementation of the LCA has resulted in calculated Global Warming Pot... [more]

Road construction takes a heavy toll on the environment. Therefore, innovative strategies to improve the environmental performances of this sector are needed, and the use of recycled materials (e.g., plastic) has been recently pursued to achieve this goal. The present work aims to (i) assess the environmental benefits deriving from the use of recycled hard plastics in combination with graphene to generate a new bitumen modifier and related asphalt mixture (AM) formulations (ii) to compare the performance of the bitumen modified using this new modifier with the bitumen modified using a traditional polymer (Styrene-Butadiene-Styrene, SBS) and the non-modified bitumen. A detailed Life Cycle Assessment (LCA) study was performed according to a cradle-to-cradle approach. Different scenarios were compared, including the variability of the pavement’s layers thickness and the amount of reclaimed asphalt pavement during the road maintenance cycles. The results demonstrated that the addition of t... [more]

This study evaluates the performance of different agricultural by-products to identify the potential effect of independent variables, using as the dependent variable the biogas production. A Box−Behnken experimental design was carried out in a pilot-scale plant of four stirred stainless-steel digesters under mesophilic semi-continuous digestion. The results obtained support the creation of a technical framework to scale up the process and further evaluation of the potential environmental impacts through life cycle assessment (LCA) methodology. A stable behaviour was achieved in 12 of the 13 experiments proposed. The highest value of daily biogas production was 2200.15 mL day−1 with a stabilization time of 14 days, an organic loading rate of 4 g VS feed daily, low C/N ratio and a 1:1 relation of nitrogen providers. The concentrations of CH4 remained stable after the production stabilization and an average biogas composition of 60.6% CH4, 40.1% CO2 and 0.3% O2 was obtained for the condit... [more]

In this work, an energetic and environmental evaluation of the electricity generation process through refuse-derived fuel (RDF) gasification coupled to a gas microturbine (GM) was performed. Two scenarios are considered with different gasification agents in RDF gasification modeling: air and air enriched with oxygen. A thermodynamic chemical equilibrium approach was used to analyze the gasification parameters. The results of RDF gasification indicate a maximum value of syngas low heating value (LHV) equal to 8.0 MJ/Nm3, obtained for an equivalence ratio of 0.3. The use of these syngas in the gas microturbine produces 79.6 kW of electrical power. For the environmental evaluation of gasification and electricity generation systems, the Life Cycle Assessment methodology was employed. The calculated environmental impacts indicate that the emission of contaminants from fossil fuel combustion (in the stage of transport by heavy load vehicles) and that the electricity consumption for equipment... [more]

High azoxystrobin (AZO), difenoconazole (DFZ), and imidacloprid (IMD) pesticide removal rates in sixteen bench-scale experiments concerning tomato washing water treatment were obtained through a UVC/H2O2 advanced oxidative process. Experimental conditions ([H2O2]0) and irradiance (EUVC) were optimized for higher degradation rates (pseudo-first-order reaction). To consider both economic aspects and environmental impacts when defining the treatment technology, as well as technological requirements, this study applied a multi-criteria decision-making method (MCDM) to assess and differentiate similar UVC/H2O2 process configurations. This allowed for the identification of the cheapest experimental arrangement with the lowest associated environmental impacts, coupled to the highest degradation rate (kIMD). After consulting experts to determine the importance of the applied criteria and measuring alternative performances, experiment E7 ([H2O2]0 = 43.5 mg L−1; EUVC = 15.0 W m−2; kIMD = 0.236 s... [more]

A considerable amount of food waste ends up in centralized treatment plants due to the lack of preventive measures, resulting in significant environmental impacts. Hospitality food waste management is even more resource-intensive because of animal by-products regulation. According to this regulation, companies must store and then consign waste to specific waste managers. The extensive need for transportation of high-moisture-content materials is the leading cause of the impact. Moreover, the management of category III animal by-products is costly for companies. A previous study has shown the economic benefits of decentralized animal by-product treatment by intensive composting in catering companies. Although the produced compost was characterized by exceptional quality parameters, it was phytotoxic. The investigation of hospitality waste management is scarcely discussed among scholars, and waste management on a regional scale is nearly absent. This study examines the regional managemen... [more]

In this work, the Life Cycle Assessment (LCA) methodology is used to examine the implications of CO2 capture from a natural gas combined cycle power plant with post-combustion carbon capture (NGCC-CCS) in Iraq, taking into account two different design scenarios. In the first scenario (retrofit), the carbon capture unit is considered as an end pipe technology that can be linked to an existing power plant. The second scenario considers a grassroots design, in which a new power plant equipped with a carbon capture unit needs to be constructed. The LCA is carried out based on different impact assessment (LCIA) methodologies of ReCipe 2016 Midpoint (H), TRACI 2.1, and IMPACT 2002+ to investigate whether the chosen LCIA method influences the LCA scenario analysis for decision support in process development. The results of three impact categories applied to both scenarios reveal a 28% reduction in Global Warming Potentials (GWPs) and a 14% and 17% increase in the Particulate Matter Formation... [more]

High energy consumption is one of the main problems of drying, a critical process for many industrial sectors. The optimization of drying energy use results in significant energy saving and has become a topic of interest in recent decades. We investigate benefits of heat recovery in a convective drying system by comparing two different scenarios. The Baseline Scenario is a conventional industrial dryer, and Scenario 1 includes the preheating of drying air by exhausts from the drying chamber. We show that the energy efficiency of the drying cycle is strictly related to the properties of the dried material and operative conditions, and performance improves significantly (by 59% to 87%) when installing a heat recovery unit (Scenario 1). Additionally, the temperature of drying air affects performance. We assess both scenarios by LCA analysis, measuring the environmental impacts and externalities of four different fuels (natural gas, light fuel oil, biomethane, and hardwood chips). Our find... [more]

Many studies have evaluated CO2 emission from batteries. However, the impact of Li-ion battery (LiB) degradation on the CO2 emissions from the material through operation phases has not been sufficiently examined. This study aims to clarify the dominant CO2 emission phase and the impact of the degradation of general industrial LiBs from repetitive cycle applications. We developed a model common to general LiB composition and calculated CO2 emissions by the LCA method using the IDEA database. Our model simplifies the degradation process, including capacity decrease and internal resistance increase. We used it in a sensitivity analysis of the carbon intensity of electricity charged to a LiB. The loss mechanism was determined by experimental data for an electric bus with an industrial LiB. The results illustrate that the carbon intensity of electricity affects CO2 emissions dominance, the operation phase for mix (71.3%), and the material phase for renewables (70.9%), and that battery degra... [more]

Net-zero climate districts are gaining wide attention at the European and international levels. Urban regeneration competitions have been launched recently to stimulate development; nevertheless, the literature does not yet provide a shared scope definition (i.e., product system). Using the process-based life cycle assessment method, the authors evaluate the climate profile of a new district in Milan (14 buildings with 36,000 m2 of gross surface area in total) aiming to become the first net-zero social housing project in Italy. The authors show in the results section how climate neutrality is achieved on the part of the real estate operator by varying the scope. The most conservative scenario (including all the emission sources considered in the analysis) indicates that the net-zero climate target is reached only by purchasing voluntary carbon credits. The authors also highlight: (i) a district composed of nearly-zero energy buildings is far from the definition of a net-zero climate em... [more]

There are different configurations selected by both industry and academia as the drivetrain for wind turbines in the power range of 10 to 16 MW. The choice of drivetrain system influences the levelized cost of energy, and, as the turbines become larger, and, therefore, costlier, there is more potential for the optimization of cost critical systems, like the drivetrain. The latter motivates the utilization of a life cycle assessment approach to profoundly influence the choice of drivetrain technology such that it offers a better compromise between the different aspects in the drivetrain life cycle. To this end, in this paper, various permanent magnet synchronous generator (PMSG)-based drivetrain technologies for 15 MW bottom-fixed and floating offshore wind turbine applications are designed and compared. The technologies under investigation are based on direct-drive, medium- and high-speed generators. The conceptual design of the drivetrain for the three technologies under consideration... [more]

The aim of this paper is to evaluate the overall life cycle environmental impact of an adiabatic compressed air energy storage (ACAES) system, which is designed to achieve the best match between the power production of a photovoltaic (PV) power plant and the power demand from the final user. The electrical energy demand of a small town, with a maximum power load of about 10 MW, is considered a case study. The ACAES system is designed with a compressor-rated power of about 10 MW and charging and discharging times of 10 and 24 h, respectively. Different sizes of the PV plant, ranging from 20 to 40 MWp, and two different solutions for the compressed air storage, an underground cavern, and a gas pipeline, are analyzed. The aim of this analysis is to compare the impacts on human health, ecosystem quality, climate change, and resource consumption of the PV power generation plant and the integrated PV-ACAES system with those of a reference scenario in which the end user demand is met entirely... [more]

The electric power industry is one of the major industries in terms of carbon dioxide (CO2) emissions, and it is necessary to explore low-carbon green power generation models. In recent years, more research has focused on the difference in carbon emissions in fossil energy versus renewable energy but ignored the impact of energy on human well-being. The life cycle assessment (LCA) method is a better method for assessing the impact of the low-carbon model on human well-being. In this paper, the carbon footprints of coal power plants and photovoltaic power (PV) plants generating 1 Kilowatt hour (kWh) of electricity are compared to analyze the degree of carbon emissions at different stages of the two models, and the environmental impact potential of the two models is analyzed using the LCA method. The differences between the two models in terms of human well-being were analyzed through questionnaires and quantified using the hierarchical analysis method. The impact of the different models... [more]

In Spain, most businesses are medium to small size enterprises, representing 90% of the total, but there is a lack of studies of the types of building this sector uses. The main objective of this paper is to present a method for the evaluation of small industrial construction projects to facilitate the introduction of eco-efficient solutions. For this, it is necessary to identify the most representative buildings and the aspects of these which have the most environmental impact. A methodology in place for the evaluation of dwelling construction is adapted, for the first time, to evaluate industrial buildings. The construction solutions characterized are those traditionally used in the sector, as identified through 87 surveys. A standardized classification of work units is proposed to enable the use of environmental product information, such as eco-labels and/or EPD, and LCA databases. The carbon footprint (CF) and water footprint (WF) are the indicators selected because of their straig... [more]

In the oil and gas industry, there has not been a consistent, concerted effort to reduce global greenhouse gas (GHG) emissions across the supply chain. In addressing this challenge, this study evaluates the potential GHG emissions reduction that may be realized through deployment of a geothermal power co-production system in two Colombian oil fields, compared to a base case where energy needs are derived through non-renewable sources such as gas and diesel. These geothermal power co-production systems make use of organic Rankine cycle (ORC) engines to convert the heat from produced oilfield fluids into electrical energy. The energy potential of this resource is evaluated through the exergy concept, and a life cycle analysis is implemented to calculate the carbon footprint using the Intergovernmental Panel on Climate Change (IPCC) 2013 methodology. In the two oil fields of interest, OFA and OFB, the results show a maximum potential energy production of 2260 kWe for OFA and 657 kWe for O... [more]

Expanding cities means increasing the need for energy in the residential sector. The supply of this energy must be in environmentally friendly ways; one method of meeting demand in the residential sector is the use of combined cooling, heating, and power (CCHP) systems. The current review paper shows that due to the high cost of gas and electricity, CCHP can be used in various sectors, such as hospitals and airports, to reduce energy consumption with lower environmental impacts by using renewable energy systems as the main driver. While CCHP systems are not feasible in tropical regions with high cooling demand, a solar hybrid system is a superior candidate for regions with sufficient radiation. CCHP can also be used in sectors such as wastewater treatment units, desalination systems, and hydrogen production units to improve performance and increase productivity. The carbon and water footprints of CCHP systems are discussed in detail. The main drivers for reducing carbon and water footp... [more]

In the context of climate change and the reduction in CO2 emissions from fossil fuel combustion, the integration of CO2 capture technologies in steam power plants is a key solution. The aim of this study was to analyze the use of ammonia, at different mass concentrations, in capturing post-combustion CO2 in a coal-fired power station and comparing it with the reference 30% MEA case. In this regard, a multi-criteria model was developed to establish the optimal solvent used, considering the least impact on technical performance, economic, and environmental indicators. As a result, the lowest CO2 capture cost was obtained for the CO2 capture process based on 7% NH3, with 59.07 €/tCO2. Integration of the CO2 capture process is more economically viable when the CO2 emissions tax is higher than 70 €/tCO2 for 7% NH3 and 15% NH3, 80 €/tCO2 for 5% NH3 and 30% MEA, and 90 €/tCO2 for 2% NH3. Regarding the overall efficiency, the energy penalty associated with the CO2 capture process integration v... [more]

At present, there are significant knowledge gaps in the research on the resource and environmental effects of rare earth exploitation, especially the carbon emission coefficient. This study applies the life cycle assessment approach to calculate the carbon footprint of producing mixed oxide rare earths using ionic rare earth resources and analyze the sources and influencing factors of the carbon footprint. The results show that the carbon footprint of producing 1 kg of mixed oxide rare earths using ionic rare earths is 17.8~24.3 kg CO2 eq, but its uncertainty is 15.54%; the total carbon footprint from 2012 to 2017 reaches 1.6 × 108~2.19 × 108 kg CO2 eq/year, and after 2018, the carbon footprint decreases to 1.51 × 108~2.07 × 108 kg CO2 eq /year. The total carbon footprint of illegal mining is around 1.50 × 108~1.59 × 108 kg CO2 eq/ year. In principle, the higher the recovery rate, the lower the carbon footprint of 1 kg REO production, but with the increase in the recovery rate, the car... [more]

Carbon-reinforced concrete (CRC) has the potential to play a pivotal role in optimizing the built environment and has therefore been experiencing a wave of research and development in the construction industry in recent years. The production of carbon fibers for CRC is energy-intensive, prompting the need to explore circular economy approaches (e.g., recycling at the End-of-Life (EoL)) to optimize the environmental performance of this material. Underdeveloped processes and a resulting lack of primary data regarding the recycling of CRC have hampered a comprehensive sustainability assessment of the novel composite building material. The novelty of this article is the detailed presentation of possible EoL scenarios for CRC and the detailed determination of the respective environmental impacts. This study aims to model EoL options within a Life Cycle Assessment (LCA), focusing on the EoL stage based on ISO 14040/44 using the GaBi ts 10.5.1.124 software and the CML2001 (2016) methodology.... [more]