Marine Ecotoxicity Research Articles

Life cycle assessment of methods for recycling retired ternary lithium batteries

Electric car sales in China are soaring. However, the battery life service is generally short, leaving room for dramatic waste related to different types of ternary lithium batteries. Since batteries contain substantial amounts of toxic substances, wrong recycling methods may significantly rise environmental pollution. Currently, China's Li-ion batteries recycling technologies are poor and research dealing with the environmental impact of recycling waste ternary lithium batteries by traditional hydrometallurgical technologies in China is not sufficient. In this paper, a life cycle assessment framework was carried out to analyze the environmental impacts of recycling LiNixCoyAl1-x-yO2 (NCA) and LiNixMnyCo1-x-yO2 (NMC) batteries using conventional hydrometallurgical techniques implemented in traditional Chinese plants. The freshwater ecotoxicity, human carcinogenicity and marine ecotoxicity of NCA batteries were higher than those of NMC batteries when the batteries were recovered by the traditional hydrometallurgical recovery method. The traditional recycling method would bring more toxicity to the environment and the traditional hydrometallurgical route is not suitable for recycling NCA-type ternary lithium batteries. Moreover, the recycling process of all three types of batteries displayed an impact on the environment with negative growth and the highest impact on the environment during the initial stage of recycling. Overall, new directions and technical updates for China's power battery recycling enterprises were provided, which can be useful for future planning.

Environmental impact assessment via life cycle analysis on ultrafiltration membrane fabricated from polyethylene terephthalate waste to treat microalgal cultivation wastewater for reusability

The current study had conducted the life cycle analysis (LCA) to assess the environmental impact of microalgal wastewater treatment via an integrated membrane bioreactor. The functional unit selected for this analysis was 1 kg of treated microalgal wastewater with contaminants eliminated by ultrafiltration membrane fabricated from recycled polyethylene terephthalate waste. Meanwhile, the applied system boundary in this study was distinguished based on two scenarios, namely, cradle-to-gate encompassed wastewater treatment only and cradle-to-cradle which included the reutilization of treated wastewater to cultivate microalgae again. The environmental impacts and hotspots associated with the different stages of the wastewater treatment process had clearly elucidated that membrane treatment had ensued the highest impact, followed by microalgal harvesting, and finally cultivation. Among the environmental impact categories, water-related impact was found to be prominent in the following series: freshwater ecotoxicity, freshwater eutrophication and marine ecotoxicity. Notably, the key performance indicator of all environmental impact, i.e., the global warming potential was found to be very much lower at 2.94 × 10−4 kg CO2 eq as opposed to other literatures reported on the LCA of wastewater treatments using membranes. Overall, this study had proffered insights into the environmental impact of microalgal wastewater treatment and its stimulus for sustainable wastewater management. The findings of this study can be instrumental in making informed decision for optimizing microalgal wastewater treatment and reutilization assisted by membrane technology with an ultimate goal of enhancing sustainability.

Life Cycle Assessment of Exopolysaccharides and Phycocyanin Production with Arthrospira platensis

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production.

Potential Environmental Impacts of a Hospital Wastewater Treatment Plant in a Developing Country

Assessing the quality of a hospital wastewater treatment process and plant is essential, especially if the presence of chemical and biological toxic compounds is considered. There is less literature on hospital wastewater treatment in developing countries because of a lack of managerial awareness and stakeholder cooperation, accompanied by the limited capacity of investment meant to upgrade the existing infrastructures. Limited access to data further hampers the reliable analysis of hospital wastewater treatment plants (WWTPs) in developing countries. Thus, based on the possibility of collecting a sufficient amount of primary (i.e., field) data, this study performed an assessment of the potential impacts generated by the WWTP of Quaid-Azam International Hospital in Islamabad (Pakistan) considering its construction and operational phases. The major identified impacts were attributed to the energy mix used to operate the plant. Marine ecotoxicity was the most impactful category (34% of the total potential impacts accounted for), followed by human carcinogenic toxicity (31%), freshwater toxicity (18%), terrestrial ecotoxicity (7%), and human non-carcinogenic toxicity (4%). An analysis of potential impacts was combined with an assessment of potential damage according to an endpoint approach. In particular, the endpoint analysis results indicated that human health damage (quantified as DALY) was mainly dependent on the “fine PM (particulate matter) formation” category (51%), followed by “global warming and human health” (43%). Other categories related to human health impacts were human carcinogenic toxicity (3%), water consumption (2%), and human non-carcinogenic toxicity (1%). The other impact categories recorded a percentage contribution lower than 1%. With respect to ecosystem damage, “global warming and terrestrial ecosystems” played a major role (61%), followed by terrestrial acidification (24%), ozone formation (10%), water consumption (5%), and freshwater eutrophication (1%). This study’s findings support an increase in awareness in the hospital management board while pointing out the need to further implement similar studies to improve the quality of decision-making processes and to mitigate environmental impacts in more vulnerable regions. Finally, this research evidenced the need to overcome the existing general constraints on data availability. Consequently, further field work, supported by hospital managers in developing countries, would help in enhancing managerial procedures; optimizing treatment plant efficiency; and facilitating the implementation of circular options, such as sludge management, that often remain unexplored.

Environmental impact and damage assessment of oil trunkline transportation by life cycle assessment method

AbstractAs climate issues gradually attract public attention worldwide, the operation of crude oil pipelines has been attached with new emission‐reduction targets. Though previous studies concerning life cycle assessment (LCA) of oil and gas pipelines have estimated the carbon footprint to some extent, there is a lack of research on life cycle carbon emissions that take the process of crude oil pipelines transportation. the main objective of this study is to build a comprehensive LCA model of carbon footprint for crude oil pipeline systems. A gate‐to‐gate analysis is provided for the LCA model, which means that the entire pipeline's life cycle from the extraction to disposal is considered. The LCA approach used both midpoint and endpoint impact assessment methods to evaluate the environmental impacts of crude oil pipeline transportation in Iran. The study analyzed the major environmental impact categories, such as greenhouse gas emissions, energy consumption, water usage, and solid waste generation. The results showed that the crude oil pipelines transportation has significant environmental impacts in Iran. The three highest impacts on the midpoint scale are marine ecotoxicity by 61.54 kg 1,4‐DCB, terrestrial ecotoxicity by 52.26 kg 1,4‐DCB and fossil resource scarcity by 40.22 kg oil eq. The endpoint impacts of three stations were also compared. The Chamran, Abadan and Zanganeh stations have 95.44%, 94.22%, and 6% impacts on human health, respectively. Also, Abadan station has the largest amount of damage to ecosystems and resources with 96.65% and 80.02%, respectively. The findings of this study could be used by policymakers, oil companies, and other stakeholders to make informed decisions and implement strategies to reduce the environmental impact of oil transportation in Iran.

A step towards sustainability: life cycle assessment of coffee produced in the indigenous community of Ocotepec, Chiapas, Mexico

Coffee is one of the tropical crops of great relevance. Mexico occupies one of the first places to produce it. Chiapas is the state that contributes the most significant amount of grain to the national and international market, harvested by organized groups such as cooperatives of origin indigenous. In these regions, cultivation is divided into five stages: cultivation, harvest, wet processing, dry processing and roasting. Thus, the agroecological approach based on the agroforestry system of coffee in the community of Ocotepec allowed generating an intercultural dialogue with a Zoque indigenous cooperative, where its members expressed the need to develop information regarding their production process and thus take the relevant decisions. Concerning environmental impacts. The life cycle analysis was applied as a methodological tool to evaluate the process of producing a kilogram of ground coffee in its honey and specialty varieties offered to the national market, showing the most significant impacts for both types of coffee. Cultivation level (water consumption around 80% and land use with effects close to 98%), wet processing (impacting the ecotoxicity of water sources close to 99% followed by marine ecotoxicity with 73%) and in its distribution stage affecting at least 15 environmental categories, likewise, comparative tests were carried out to calculate the carbon footprint and the water footprint, with shade-grown honey coffee being the type of coffee that has the most negligible environmental impact and contributes the most profits to the cooperative.

Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment.

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90min, 90°C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90min of reaction time, 150 W of XE specific power input) rendered maximum 61.3mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3mol%) compared to the individual MW (34.52mol%) and XE (22.67mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Environmental Life Cycle Assessment of Silage Maize in Relation to Regenerative Agriculture

The demand for agricultural products is growing and is resulting in significant environmental impacts due to the overuse of fertilizers (and pesticides in some cases). There is a continued need to find sustainable methods in agricultural systems without harming the environment. Regenerative agriculture can be considered as one of the best methods of sustainable agriculture. The aim of this comparative life cycle assessment (LCA) study was to quantify the environmental impacts associated with the production of silage maize at different doses of fertilizers and pesticides under conventional agriculture and without the use of fertilizers and pesticides under regenerative agriculture. The input data were obtained from the experimental fields and supplemented by background process databases of Ecoinvent, World Food Live Cycle Assessment Database (WFLCD), and the French database AGRIBALYSE. The results of the study were related to six midpoint impact categories: global warming, marine eutrophication, freshwater eutrophication, freshwater ecotoxicity, marine ecotoxicity, and terrestrial ecotoxicity. Although the variant of growing silage maize without the use of fertilizers and pesticides according to the principle of regenerative agriculture showed the lowest burden on the environment, the yields of the cultivated silage maize were 43–55% lower than those of the fertilized variants.

Environmental sustainability assessment of softwood and hardwood seedlings production in forest nurseries: A case study from Pakistan.

This article describes the environmental impacts of producing a single seedling in forest nurseries of selected districts (i.e., Haripur, Abbottabad, and Mansehra) of Hazara Division of Khyber Pakhtunkhwa, Pakistan using the life cycle assessment (LCA) approach. This study was based on the cradle-to-gate approach which begins with the pre-nursery stage and progresses toward the main nursery before transplanting seedlings into the plantation site. Data or life cycle inventory (LCI) of seedling production were collected through questionnaire surveys and personal meetings with forest nurseries managers and workers regarding consumption of different inputs such as electricity, diesel, fertilizers, herbicides, and polyethylene bags, organic manure, and water consumption. The SimaPro software version 8.5 and the CML2000 v2.05 environmental model was applied to perform life cycle impact assessment (LCIA) for a single seedling production in forest nurseries in the study area. In line with the objectives of the study, primary data regarding inputs and outputs of the nurseries were collected from 35 nurseries in the study area by using a random questionnaire method. In addition, secondary data were taken from online databases such as Eco-invent v.3.2 CORRIM and peer-reviewed published literature. For this study, a functional unit of a single seedling was considered. Production weighted average data were modeled in the latest environmental modeling software i.e., SimaPro v.8.5 for ten US-EPA most wanted environmental impacts, such as global warming potential (GWP), abiotic depletion (AD), eutrophication potential (EP), acidification potential (AP), freshwater aquatic eco-toxicity (FAE), marine water eco-toxicity (MWE), terrestrial eco-toxicity (TE), ozone layer depletion (OLD), photochemical oxidation (PO), and human toxicity (HT). The results showed that the highest environmental impact posed by a single seedling was marine aquatic eco-toxicity (11.31360 kg 1,4-DB eq), followed by global warming potential (0.02945 kg CO2 eq) and (0.01227 kg 1,4-DB eq) human toxicity. The primary reason for these environmental burdens was the use of synthetic fertilizers in forest nurseries and the consumption of fossil fuels in nursery mechanization and transportation activities. The total cumulative energy demand for a single seedling was (0.800 MJ) with more than 90% contribution from fossil fuel energy resources such as petrol and diesel. It is therefore highly recommended to use renewable energy resources and organic fertilizers instead of chemical fertilizers in forest nurseries to avoid and minimize greenhouse gas emissions (GHS) and other toxic emissions in the study area.

Environmental impacts of a digital health and well-being service in elderly living schemes

Over the past decade, digitalization and digital technologies (DTs) have undergone rapid evolution, transforming how goods and services are produced and consumed in modern societies. Health and well-being sectors have embraced this digital revolution. Besides the economic and social benefits, digitalization can significantly enhance patient diagnostics and prognostics while improving overall service efficiency. To ensure long-term sustainability, it is important to assess and reduce the environmental impacts of digital services. This article examines the life cycle impacts of a digital service implemented in three elderly living schemes (ELSs) located in the United Kingdom (UK). The digital service consists of six electronic devices (EDs) that enable communication between residents, visitors, staff, and offsite monitoring (OM). The equipment is connected using Power over Ethernet (PoE) technology, which includes smart network switch and uninterruptable power supply units. The digital service's global warming potential (GWP) was estimated at 718–741 kg CO2 eq./resident for two of the ELSs and 1509 kg CO2 eq./resident for a third ELS, considering a service period of 20 years. The reason for the significant difference is the greater use of air conditioner (A/C) units to cool down server rooms and fewer residents in the third scheme. The consumption of electricity was found to be the main contributor to most of the environmental impacts. However, in certain categories such as mineral resource scarcity, freshwater eutrophication, and freshwater and marine ecotoxicity potentials, printed circuit boards (PCBs) were the main contributors. A sensitivity analysis considering different national electricity mixes demonstrated that the French electricity grid promoted the reduction in 14 impact categories, whereas the German, Italian, Spanish and Japanese grids increased on average impacts on most categories. Another sensitivity analysis demonstrates that reducing A/C unit running time by 28% resulted in an average impact reduction of 5.5%, becoming equivalent to the results obtained for the French electricity grid. Finally, extending the expected lifespan of electronic equipment by 20% yielded the highest average decrease in environmental impacts (8.1%). While digitalization has the potential to enhance patient healthcare and reduce costs, it is crucial to carefully assess its environmental impacts and implement mitigation strategies to ensure sustainable development in the healthcare sector.

The Environmental Impact of Reusing Post-Earthquake Demolition Waste: İskenderun Case Study

Producing recycled aggregate from construction and demolition waste generated by earthquakes
 and using it as raw material in concrete production would be effective for urgent waste
 management after disasters and to reduce the environmental impact of concrete production by
 decreasing resource use. In this study, the life cycle assessment (LCA) method was used to
 examine the environmental implications of concrete produced using recycled aggregates (RA)
 derived from construction and demolition waste (CDW) of buildings demolished after the
 earthquake that struck Iskenderun and was centered in Kahramanmaraş. In addition, the
 environmental consequences of an equal volume of concrete produced in the same location
 utilizing natural aggregates (NA) were assessed. For the LCA of these two types of concrete,
 openLCA software and the ReCiPe midpoint database were used. LCA was conducted
 considering terrestrial ecotoxicity, climate change, terrestrial acidification, photochemical
 oxidant formation, marine ecotoxicity, human toxicity, freshwater ecotoxicity, ozone depletion,
 particulate matter formation, marine eutrophication, and ionizing radiation impact factors. The
 results show that cement has the highest impact on the environment by far. RAC (recycled
 aggregate concrete) has a lower environmental impact than NAC (natural aggregate concrete), in
 general.

Life cycle assessment of coal mines of diverse scales over time in China

Coal mining has important detrimental effects on the environment and human health. By the end of 2022, China mined more than 4 billion tons of raw coal, and coal mining contributed to adverse environmental impacts. The objective of this work is to evaluate the environmental impacts emanated from coal mines in different periods (construction period, production period and closing period) and to find the relationship between coal mine scale and ecological impacts. This study uses coal mines that produce 0.45 Mt/a (considered a medium sized mine), 3 Mt/a and 8 Mt/a (both classified as large mines in this study) and a 12 Mt/a extra-large coal mine. Based on the time dimension, the mine life cycle was classified into construction, production and closing period, and the life cycle assessment method was used to conduct environmental assessment. The main influencing substances and key processes were tracked. The results indicated that mining engineering and gangue are the main factors affecting the construction and production periods of coal mines. Freshwater ecotoxicity, marine ecotoxicity, and human toxicity are the main environmental effects of coal produce, and they are mostly brought up by the release of hazardous elements like copper, chromium, zinc, nickel, and copper. Furan, formaldehyde, and chromium emissions during mine closure can be effectively reduced through environmental compensation, however coal mines' environmental compensation during mine closure is minimal. The environmental impact of coal mines producing 3 Mt and 8 Mt annually is minimal. The environmental impact of 0.45 Mt/a and 3 Mt/a coal mines is more prominent in the construction period. The pollutant discharge throughout the production phase, particularly the metal leaching discharge from gangue, needs to receive more attention from the 8 Mt/a and 12 Mt/a coal mines. Additionally, the larger the scale of coal mine production, the greater the proportion of the total environmental impact in the production stage.

Life cycle analysis of common landfill final cover systems focusing on carbon neutrality

Carbon emissions from landfill construction and management have become a global concern. Life cycle analysis (LCA) has been widely used to assess the environmental impacts of engineered infrastructures over their lifetimes. LCA has also been applied to landfill leachate and gas management, but rarely to landfill final cover systems. This paper reports the results of an LCA of the following landfill final cover systems: compacted clay cover, geomembrane cover, cover with capillary effects (CCBE), dual capillary barrier cover, three-layer landfill cover system using natural soils, three-layer cover using recycled concrete aggregate (RCA) and biochar-amended three-layer landfill cover system using RCA. The LCA assessment of landfill cover considers the cost, carbon emissions and carbon sequestration during the production, construction and operation phases. The effects of landfill cover on global warming, freshwater eutrophication, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity and fossil resource scarcity are also evaluated. In addition, the sensitivities of cost and carbon emission to the use of electric-powered machines and transportation distance are analysed. It is revealed that the three-layer cover system using RCA and biochar has the lowest unit cost and carbon emission of all of the covers, up to 88 % and 66 % lower, respectively, than those of the other six covers. In addition, this cover system has the highest carbon sequestration rate, with a value of 47.9 kg CO2/(y·m2), four times higher than that of the compacted clay cover. Finally, this sustainable cover mitigates global warming and reduces adverse environmental impacts by up to 82 %. Therefore, the biochar amended three-layer cover system using RCA without geomembrane offers the greatest economic benefits, performs effectively in terms of the pursuit of carbon neutrality and promotes sustainable development.

Assessing the environmental impacts of copper cathode production based on life cycle assessment.

The demand for copper is growing considerably in parallel with economic and technological development. The rate increase in copper consumption in Iran increases pressure on the numerous unexploited mines in southeast Iran and causes the environmental crisis alongside the northern Levar wind in this area. Given this, this study systematically explored the environmental impacts of a one-ton copper cathode processing operation from a cradle-to-gate perspective, using life cycle assessment (LCA). Moreover, the release of greenhouse gases and the energy consumption during the copper cathode production were also assessed. The results indicated that sulfuric acid use in the smelting and extraction stages, metal leaching from tailings, and CO2 dominated more than 50% of contributions to freshwater and marine ecotoxicity, human toxicity, and global warming. The energy analysis revealed 88.92% of crude oil use especially for the electrowinning stage, which should be promoted technologically. For global warming, the indirect CO2 emission from electricity consumption using fossil fuels was the main contributor (94.56%). Therefore, shifting from conventional energy systems to renewable energy systems could alleviate the overall environmental impact. For a 0.57-ton sulfuric acid effluent per one ton of copper cathode production, its treatment and reuse in the process is recommended. Summing up, the results of this study provide the environmental hot spots for copper cathode production for further investigation. Integr Environ Assess Manag 2024;20:1180-1190. © 2023 SETAC.

Gate-to-gate life cycle analysis of a pilot-scale solar driven two-step thermochemical hydrogen sulfide decomposition for hydrogen production

Hydrogen is one of the most viable options towards decarbonization. It is crucial to upscale the hydrogen economy considering the current state of the environment due to the adverse effects of climate change. In this study, a gate-to-gate Life cycle assessment (LCA) was conducted on a hydrogen sulfide splitting model that replicates a pilot-scale plant by integrating the two-step solar thermochemical H2S decomposition using SimaPro version 9.4.0 software. This analysis starts from the treatment of H2S gas released by the refineries as waste and ends at the production and storage stage of hydrogen. There are two functional units used in this study which are ‘1 kg of H2’ to assess the operational phase of the simulation plant and ‘1 unit of H2S splitting plant’ to determine the environmental performance of the construction of the plant. The top three most impacted midpoint level categories in the operational phase are human carcinogenic toxicity (HTP), freshwater ecotoxicity and marine ecotoxicity with an amount of 3.66 × 10−4, 1.10 × 10−4, and 1.40 × 10−4 kg 1,4-DCB respectively. Electricity has a higher relative contribution to this technology due to the high amount of steel used during the construction of solar tower. Meanwhile, treating H2S leaves a positive impact towards every midpoint indicator, mainly on terrestrial acidification, fine particulate matter formation and ionizing radiation. The H2S splitting technology was set as the baseline to compare with various other H2 production technologies. Scenario analysis was assessed by setting the solar-powered electricity as the baseline and was compared with electricity from different sources such as wind, nuclear and the United Arab Emirates (UAE) grid for the H2S splitting plant. Moreover, uncertainty analysis using Monte Carlo simulation suggests that the probability of gaining results of HTP is the highest between 3.62 × 10−4 to 1.34 × 10−3 kg 1,4-DCB. It can be concluded that electricity powered by renewable sources significantly reduces the environmental burden from the scenario analysis conducted.

Life-cycle assessment of microwave-assisted pyrolysis of pine sawdust as an emerging technology for biodiesel production

Although biofuels are often presented as a renewable and eco-friendly substitute to fossil fuels, it is crucial to have a comprehensive understanding of the complete environmental consequences of biofuel production to make well-informed choices about their usage. This study evaluated the environmental impacts of producing biodiesel from microwave-assisted pyrolysis (MAP) of pine sawdust using life-cycle assessment. A cradle-to-gate system boundary approach encompassing pine cultivation, biomass pre-processing, pyrolysis, and biofuel synthesis via transesterification was used. The ecoinvent v3.7 in openLCA v2.0 software was used to assess the environmental sustainability of the system. The ReCiPe 2016 (H) midpoint impact assessment methodology was used to analyze 18 environmental impact categories. The results showed that producing 1 kg of biofuel from MAP of pine sawdust had environmentally favorable impacts for most categories except global warming potential (1.18 kg CO2 eq.), photochemical oxidant formation (0.71 kg NMVOC eq.), and human toxicity (2.46 kg 1,4-DCB eq.). Biomass production contributed significantly to global warming, freshwater ecotoxicity, human toxicity, and marine ecotoxicity. Pyrolysis contributed 33 % of global warming potential due to non-condensable gas emissions. Biofuel synthesis impacted human toxicity, photochemical oxidant formation, and terrestrial ecotoxicity, mainly due to methanol use. Implementing sustainable practices such as using organic fertilizers, optimization of transportation routes, implementing gas cleaning technologies and effective waste management practices can enhance the environmental performance of this biofuel production system.

Life cycle assessment and techno-economic analysis for biofuel and biofertilizer recovery as by-products from microalgae

Although there are several studies on the hydrothermal carbonization of microalgae biomass for value-added products and their potential environmental impacts, the feasibility of scaling-up and the environmental and economic analysis need to be investigated. This study produced solid biofuel and biofertilizer under two operating conditions (170 °C, 10 min, 7 bar; or 130 °C, 50 min, 2 bar, respectively). Also, investigated the environmental performance and techno-economical viability of producing solid biofuel and biofertilizer from microalgae. Scale-up modeling used Aspen Plus software to obtain optimized production processes, energy data, equipment requirements, and costs, which were used to support the economic and environmental analyses. The Recipe Midpoint method showed that the solid biofuel had a higher environmental impact than the biofertilizer, especially in the Freshwater Eutrophication category (almost 7 times higher), Fossil Resource Scarcity (4.2 times higher), Global Warming, and Marine Ecotoxicity (both around 2.7 times higher). The damage assessment results showed that the production of solid biofuel was more impactful, with Human Health impacts 2 times higher, Ecosystem 1.6 times higher, and Resource 4.3 times higher than those caused by biofertilizer production. The biofertilizer production scenario emerged as the most economically viable option for hydrothermal carbonization valorization. The negative net present value and the inability to achieve the return on investment within a 30-year timeframe made the solid biofuel production scenario unviable. Thus, biofertilizer production from hydrothermal carbonization of microalgae biomass cultivated in wastewater is technically, economically, and environmentally feasible, whereas the same cannot be said for the biofuel evaluated.

Engineering properties and sustainability evaluation of crushed low grade magnesite mortars

China is the country in the world with the most abundant magnesite resources. The ever-increasing deposit of low grade magnesite ore derived from the process of magnesium products has occupied a substantial space and caused environmental damages. In this study, crushed low grade magnesite (CLGM) was prepared and then applied in mortar as fine aggregate to partially or entirely replace natural river sand (30%, 60%, and 100%), while 100% limestone sand (LSS) was applied as the reference group. The findings of this study demonstrated a positive correlation between the ratio of CLGM substitution and the improvement of both engineering properties and sustainable potential in the mortar. Compared with the control group at 28 d, the 100% CLGM mortar exhibited improvements of up to 6% in splitting strength, 25.86% in compressive strength, 16% in porosity reduction, 22.22% in impermeability enhancement, 27.52% in resistance to chloride ion penetration, 21.66% in frost resistance (after 150 cycles), and a remarkable 54.8% in anti-abrasion property. Furthermore, the sustainability evaluation assessed its potential societal value, and highlighted its reduced production costs (down 52.28%) and impressive environmental benefits (notable decreases of 28.3% in ozone depletion potential, 33.2% in land use potential, 38.7% in marine ecotoxicity, and 33.9% in fossil resource scarcity). These findings well demonstrated the feasibility of adopting magnesite tailings as a substitute of conventional aggregate within the construction sector along with substantial economic savings and positive environmental ramifications. The successful application of CLGM mortar in cleaner production can further facilitate the sustainable advancement of environment and construction industry.

Life cycle assessment of Bitcoin mining in the top ten miner countries

An unprecedented emergence has occurred for the cryptocurrencies among enterprises, customers, and investors as a result of the growing number of internet connections worldwide. The most popular cryptocurrency is Bitcoin representing the rise of digital payment systems. Though, harsh criticism has been also created for cryptocurrencies about their environmental sustainability and power consumption, decelerating the acceptance of bitcoin by consumer as a means of payment. The ecological impact or footprint of a process is determined mainly through life-cycle-assessment (LCA) quantifying all material flows’ inputs and outputs for a process or product and their effect on the environment. This study provides LCA-based framework to show the environmental impacts of Bitcoin mining from top ten miner countries (China, USA, Kazakhstan, Russia, Iran, Malaysia, Canada, Germany, Ireland, Norway). The results show that with the share of 53.3% of the world’s mining, China has the most negative environmental impact specially in marine ecotoxicity with 26.8 kg 1,4-DCB and human health with 0.0043 DALY but with the equal mining ratio Germany and Kazakhstan have the most negative environmental impacts.

Toward Zero Emission Construction: A Comparative Life Cycle Impact Assessment of Diesel, Hybrid, and Electric Excavators

Due to an extensive usage of heavy machinery, the construction sector is criticized as one of the major CO2 emitters. To address climate concerns, mitigating these greenhouse gas (GHG) emissions is important. This study aimed to strategize for “zero emission construction” by assessing the life cycle environmental impacts of diesel, electric, and hybrid construction machinery. By applying life cycle assessment (LCA) principles with adherence to ISO 14040/44 methodologies, this study scrutinizes the environmental repercussions of a standard excavator over 9200 effective operational hours, from raw material acquisition to end-of-life disposal. The results demonstrate a significant reduction in global warming potential (GWP), ozone depletion potential (ODP), and acidification potential (AP) in transitioning from diesel to hybrid and fully electric machines. A nominal increase due to this shift also occurred and impacted categories such as human carcinogenic toxicity (HT), freshwater eutrophication (EP), and marine ecotoxicity (ME); however, a more significant upsurge was noted in terrestrial ecotoxicity (TE) due to battery production. Thus, this study highlights the need for a careful management of environmental trade-offs in the shift toward electrified machinery and the importance of centering on the environmental profile of the battery. Future work should focus on enhancing the environmental profile of battery production and disposal, with policy decisions encouraging holistic sustainability based on green energies in construction projects.