Life Cycle Assessment Perspective Research Articles

Enhancing environmental performance in biogas production from wastewater-grown microalgae: A life cycle assessment perspective

The production of biogas from microalgae has gained attention due to their rapid growth, CO2 sequestration, and minimal land use. This study uses life cycle assessment to assess the environmental impacts of biogas production from wastewater-grown microalgae through anaerobic digestion within an optimized microalgae-based system. Using SimaPro® 9 software, 3 scenarios were modeled considering the ReCiPe v1.13 midpoint and endpoint methods for environmental impact assessment in different categories. In the baseline scenario (S1), a hypothetical system for biogas production was considered, consisting of a high rate algal pond (HRAP), a settling, an anaerobic digester, and a biogas upgrading unit. The second scenario (S2) included strategies to enhance biogas yield, namely co-digestion and thermal pre-treatment. The third scenario (S3), besides considering the strategies of S2, proposed the biogas upgrading in the HRAP and the digestate recovery as a biofertilizer. After normalization, human carcinogenic toxicity was the most positively affected category due to water use in the cultivation step, accounted as avoided product. However, this category was also the most negatively affected by the impacts of the digester heating energy. Anaerobic digestion was the most impactful step, constituting on average 60.37% of total impacts. Scenario S3 performed better environmentally, primarily due to the integration of biogas upgrading within the cultivation reactor and digestate use as a biofertilizer. Sensitivity analysis highlighted methane yield's importance, showing potential for an 11.28% reduction in ionizing radiation impacts with a 10% increase. Comparing S3 biogas with natural gas, the resource scarcity impact was reduced sixfold, but the human health impact was 23 times higher in S3.

The valorisation of steel mill off-gas via chain elongation into higher value-added products: A prospective life cycle assessment

Nowadays, one of the greatest challenges for the steel industry is decarbonisation to decrease its pressure on the environment. For this purpose, deploying carbon capture and utilisation technologies such as syngas fermentation can be instrumental, as they allow carbon in steel mill off-gas to be converted into ethanol. However, as ethanol is of relative low value, technologies that can upgrade it towards higher-value chemicals are becoming attractive. One such a technology is chain elongation, as it can convert ethanol effluents from syngas fermentation into caproic acid, which can subsequently be used as a feedstock to produce chemicals such as plasticisers. As information regarding the environmental sustainability of chain elongation is limited, in this study, a prospective environmental hotspot analysis on chain elongation was performed, assessing climate change and resource footprint indicators, from a Life Cycle Assessment perspective, based on a theoretical scale-up. In addition, climate change impacts of a novel basic oxygen furnace gas (BOFG) to plasticiser value chain integrating the theoretically scaled-up chain elongation technology (PLAST) were assessed and compared with two other valorisation routes, considering a US and a European scenario: BOFG incineration with electricity production (ELEC) and syngas fermentation for the production of ethanol for use as a fuel (ETOH). The hotspot analysis showed that electricity and chemicals consumption, mainly K-acetate, were the largest contributors to both the climate change and resource consumption footprint. For the US scenario, the novel PLAST route showed similar climate change impacts to the ETOH route, while the impacts were 15% higher than those of the ELEC pathway. In the European scenario, with a greener electricity mix, the PLAST route showed similar impacts compared to both the ELEC and ETOH routes. Although uncertainties lie within the results, this study highlights the potential of chain elongation as a part of an alternative carbon capture and utilisation pathway for the steel industry. For this however, further technological advances are required, such as changes in process configurations and increases in caproic acid productivity, which should be the focus of future research.

Reuse of Lithium Iron Phosphate (LiFePO4) Batteries from a Life Cycle Assessment Perspective: The Second-Life Case Study

As of 2035, the European Union has ratified the obligation to register only zero-emission cars, including ultra-low-emission vehicles (ULEVs). In this context, electric mobility fits in, which, however, presents the critical issue of the over-exploitation of critical raw materials (CRMs). An interesting solution to reduce this burden could be the so-called second life, in which batteries that are no longer able to guarantee high performance in vehicles are used for other applications that do not require high performance, such as so-called stationary systems, effectively avoiding new over-exploitation of resources. In this study, therefore, the environmental impacts of second-life lithium iron phosphate (LiFePO4) batteries are verified using a life cycle perspective, taking a second life project as a case study. The results show how, through the second life, GWP could be reduced by ‒5.06 × 101 kg CO2 eq/kWh, TEC by ‒3.79 × 100 kg 1.4 DCB eq/kWh, HNCT by ‒3.46 × 100 kg 1.4 DCB eq/kWh, ‒3.88 × 100 m2a crop eq/kWh, and ‒1.12 × 101 kg oil eq/kWh. It is further shown how second life is potentially preferable to other forms of recycling, such as hydrometallurgical and pyrometallurgical recycling, as it shows lower environmental impacts in all impact categories, with environmental benefits of, for example, ‒1.19 × 101 kg CO2 eq/kWh (compared to hydrometallurgical recycling) and ‒1.50 × 101 kg CO2 eq/kWh (pyrometallurgical recycling), ‒3.33 × 102 kg 1.4 DCB eq/kWh (hydrometallurgical), and ‒3.26 × 102 kg 1.4 DCB eq/kWh (pyrometallurgical), or ‒3.71 × 100 kg oil eq/kWh (hydrometallurgical) and ‒4.56 × 100 kg oil eq/kWh (pyrometallurgical). By extending the service life of spent batteries, it may therefore be possible to extract additional value while minimizing emissions and the over-exploitation of resources.

An application of the graph approach to life-cycle optimisation of vehicle electrification

Although durable goods with low energy consumption are being promoted to achieve a decarbonised society, from the perspective of life-cycle assessment, the choice of new durable goods may increase CO2 emissions. To address this problem, research has been conducted on product replacement based on life-cycle optimisation (LCO), a method for identifying a replacement life span that minimises life-cycle CO2 emissions. However, several additional assumptions complicate the analysis of replacement patterns of products and conditional formulas because cumulative emissions do not increase linearly when considering energy mix and technology improvement, and it is difficult to extend the model to optimisation methods in previous LCO studies. This study developed a new LCO approach by applying the shortest path problem to graph theory. Our methodology can contribute to the following: (i) it is computationally inexpensive; (ii) it is intuitively easy to add complex conditions, such as various policy scenarios and parameter changes; and (iii) once the graph of replacement patterns is defined, the optimal solution can be derived using existing solution methods, such as the Dijkstra algorithm. As a case study, we focused on vehicle replacement, which is a major source of CO2 emissions and is being electrified. In particular, we identified vehicle switching paths that minimise life-cycle CO2 emissions by considering changes in Japan’s energy mix and alternative fuel vehicle (AFV) characteristics. We determined that the optimal vehicle replacement path method to reduce CO2 emissions is to switch first to plug-in hybrid electric vehicles (PHEVs) and then to battery electric vehicles (BEVs). Thus, we suggest that the transition to electric vehicles requires a step-by-step process. This methodology is not only conducive to AFV deployment for decarbonisation but can also be applied to other products, such as air conditioners and lighting. Thus, various transition policies could be formulated using our methodology.

Building renovation plan - introducing energy and cost into the managerial perspectives: A case study

Implementing more stringent energy requirements for public buildings has the potential to expedite the renovation rate of building stocks. While many studies have explored optimal renovation solutions to reduce energy consumption and cost, few have established a comprehensive building portfolio strategy from the perspective of portfolio managers. This study addresses this gap by developing a framework that empowers building portfolio managers to make informed decisions regarding building renovations. Through an in-depth case study, the current workflow for determining renovation needs, which involves analyzing maintenance requirements, building usability, and adaptability, is enhanced by incorporating a cost-optimal renovation framework. The study utilizes building simulations and life cycle cost analysis to assess the energy reduction potential of six school buildings requiring renovation. The results demonstrate a potential for energy use reduction, ranging from 11% to 44% when incorporating energy-saving measures into the renovations. Cost-optimal solutions are achieved for two buildings, resulting in energy reduction ranging from 31% to 36% and cost reduction ranging from 7% to 8%. The primary contribution of this research is developing a framework that reduces ambiguities of which buildings a portfolio manager should prioritize for renovation. By identifying current performance and improvement potential, the framework enables benchmarking against energy performance classes, aiding in strategic decision-making. However, the study also underscores the complexities of assessing a diverse building stock from a bottom-up perspective. Barriers such as obtaining high-quality data, scaling assessments, time constraints, and knowledge transfer are problems to overcome. Additionally, evaluating various building typologies with diverse characteristics, including those with legal restrictions due to heritage status, presents unique challenges. Future research directions should focus on expanding the framework to incorporate a life cycle assessment perspective. This approach will ensure a comprehensive building portfolio strategy that mitigates the risk of sub-optimal solutions.

Current advances in produced water treatment technologies: a perspective of techno-economic analysis and life cycle assessment

Current advances in produced water treatment technologies: a perspective of techno-economic analysis and life cycle assessment

Environmental potential of recycling of plastic wastes in Australia based on life cycle assessment

Plastic consumption in Australia is steadily increasing and is estimated to reach 8.8 million tonnes by 2050. Alongside plastic consumption, plastic waste management (PWM) faces rising environmental challenges in Australia as most of them are currently landfilled. Therefore, the Australian government has published a policy to transition to a circular economy as well as a new strategy for PWM with higher recycling rates. To understand the implications of the policy changes and the environmental impacts of End-of-Life (EoL) options, life cycle thinking is necessary. This study evaluates and compares the environmental impacts of the Australian PWM for 2018–2019 to the policy envisaged for 2030 that includes higher recycling rates and waste export bans from a life cycle assessment (LCA) perspective. From the results, it can be seen that the current PWM is majorly linear (take, make, use and dispose) as most of the wastes gets landfilled and exported to other countries but the future PWM strategy for 2030 results in higher resource recovery and significant reduction in the environmental impacts. There is a reduction in Global Warming Potential (GWP) by a factor of almost 10, if the recycling rates increase from 13 to 70%. The state and the federal governments along with other stakeholders need to implement stringent measures to recover plastic wastes if a transition to a circular economy is to happen by 2030.

Precision co-composting of multi-source organic solid wastes provide a sustainable waste management strategy with high eco-efficiency: a life cycle assessment.

With the increase of organic solid wastes (OSWs), current waste management practices, such as landfill, incineration, and windrow composting, have shown weaknesses in both resource recycling and environmental protection. Co-composting has been used to achieve nutrient and carbon recycling but is accused of high ammonia emission and low degradation efficiency. Therefore, this study developed a precision co-composting strategy (S3, which adds functional bacteria generated from food processing waste to a co-composting system) and compared it with the current OSW treatment strategy (S1) and traditional co-composting strategy (S2) from a life cycle assessment (LCA) perspective. The results showed that compared with S1, the eco-efficiency increased by 31.3% due to the higher economic profit of S2 but did not directly reduce the environmental cost. The addition of bacterial agents reduced ammonia emissions and shortened composting time, so compared with S1 and S2, the environmental cost of S3 was reduced by 37.9 and 43.6%, while the economic profit increased by 79.8 and 24.4%, respectively. The changes in environmental costs and economic benefits resulted in a huge improvement of S3's eco-efficiency, which was 189.6 and 121.7% higher than S1 and S2. Meanwhile, the adoption of S3 at a national scale in China could reduce the emission of 1,4-dichlorobenzene by 99.9% compared with S1 and increase profits by 6.58 billion USD per year. This study proposes a novel approach that exhibits high eco-efficiency in the treatment of OSWs.

Development of Enzyme-Based Approaches for Recycling PET on an Industrial Scale.

Pollution by plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PUR), polyamide (PA), polystyrene (PS), and poly(ethylene terephthalate) (PET) is now gaining worldwide attention as a critical environmental issue, closely linked to climate change. Among them, PET is particularly prone to hydrolysis, breaking down into its constituents, ethylene glycol (EG) and terephthalate (TPA). Biorecycling or bioupcycling stands out as one of the most promising methods for addressing PET pollution. For dealing with pollution by the macrosize PET, a French company Carbios has developed a pilot-scale plant for biorecycling waste PET beverage bottles into new bottles using derivatives of thermophilic leaf compost cutinase (LCC). However, this system still provides significant challenges in its practical implementation. For the micro- or nanosize PET pollution that poses significant human health risks, including cancer, no industrial-scale approach has been established so far, despite the need to develop such technologies. In this Perspective, we explore the enhancement of the low activity and thermostability of the enzyme PETase to match that of LCC, along with the potential application of microbes and enzymes for the treatment of waste PET as microplastics. Additionally, we discuss the shortcomings of the current biorecycling protocols from a life cycle assessment perspective, covering aspects such as the diversity of PET-hydrolyzing enzymes in nature, the catalytic mechanism for crystallized PET, and more. We also provide an overview of the Ideonella sakaiensis system, highlighting its ability to operate and grow at moderate temperatures, in contrast to high-temperature processes.

Energy Recovery from Residual Municipal Solid Waste: State of the Art and Perspectives within the Challenge to Climate Change

Among the technologies for the recovery of energy from waste, in particular residual municipal solid waste (rMSW), combustion is the most widely used thermo-chemical treatment process associated with thermal and electric power production by a steam cycle, named, shortly, Waste to Energy (WtE). Today, more than 500 WtE plants in the EU, about 400 in China and 76 in the USA are in operation, based on efficient technologies and advanced air pollution control systems. Energy recovery can be accomplished also by means of gasification; however, the presence of impurities together with the atmospheric pressure, at which syngas is normally produced, impose the feeding of syngas to a conventional steam cycle, leading to generally lower performances than WtE. The energy recovered by WtE offsets traditional energy sources such as fossil fuels and related emissions, providing savings in term of climate change. However, the savings obtainable by replacing electricity and/or heat will diminish as the energy systems will hopefully become increasingly renewable. Over this medium–long-term horizon, one possibility is to capture the CO2 from WtE flue gases and to store/use it. From the life cycle assessment perspective, it has been calculated that the introduction of CO2 capture and storage in WtE, despite energy penalties, is able to reduce the impact on climate change. The alternative approach, proposed to contain the emissions of greenhouse gases in the thermal treatment of waste, is using the carbon contained in it to produce commonly used chemical compounds (waste to chemicals). The benefits, in terms of reductions of greenhouse gases, are expected from the possibility of obtaining chemicals that can replace their analogue normally produced from fossil sources. To date, only one WtC demonstration plant is operating by being fed by rMSW-derived waste, and some similar initiatives are planned, but still adequate assurances in terms of robust knowledge of the involved complex processes, above all, if applied to highly inhomogeneous feed streams such as those obtained from rMSW, are not available. Once the several initiatives come to completion, it will enable waste management professionals to assess performance and to begin to consider such a facility in their planning.

Exploration of sustainable driving path of rural domestic wastewater treatment-from the perspective of life cycle assessment

Most rural wastewater treatment facilities require electricity to maintain operation. Traditional fossil energy consumption increases the environmental load and greenhouse gas emissions. Wind-solar power generation is widely recognized as a renewable energy technology. However, conventional wind-solar power systems need batteries to store energy, which can lead to secondary pollution. Additionally, the alternating aerobic and anaerobic process were crucial for nitrogen and phosphorus removal, and some distributed wastewater treatment systems do not require continuity operation. Therefore, this study reports on a wind–solar power generation mode without batteries (Mode-II) to control and drive a bioecological rural domestic wastewater treatment system with a scale of 0.5 m³/day. By logic control, the inspired combination of power generation capacity and treatment process requirements was realized. The effluent CODcr, NH4+-N, and TN concentrations were 14.63 ± 7.02, 1.39 ± 1.63, and 8.65 ± 4.02 mg/L, with removal rates of 89.01 ± 4.15%, 88.58 ± 2.28%, 75.47 ± 8.84%, respectively. From the perspective of environmental load and carbon emissions, based on life cycle assessment theory, this novel approach was compared with the traditional wind–solar power generation driven mode with battery storage (Mode-I) and mains power driven mode (Mode-III). The environmental load and carbon emissions of Mode-II were 1.08 kPt and 2836 kg CO2 eq by end-of-life (25 years), the lowest of the three modes. Compared with the mains power drive mode, the environmental load and carbon emissions of Mode-II can be repayment until years 6 and 2. The supercapacitors and solar panels were the main source of environmental load and carbon emissions for Mode-II. Overall, Mode-II was found to be the most environmentally friendly mode all over the China, which is expected to be promoted in the field of rural wastewater treatment.

Carbon footprint accounting for cigar production processes: A life cycle assessment perspective

Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally. Cigarette factories are a key link in the tobacco industry’s production chain, and using data provided by a cigarette factory in China we conduct a life cycle assessment to account for the carbon footprint of cigar production in cigarette factories. The results of the assessment show that factory air conditioning is the most important contributor to the environmental load of the cigar manufacturing process, while electricity is the key factor that contributes the greatest environmental load across all of the processes in the product life cycle. In addition, packaging, including small boxes and cigarette cartons, have a significant impact on the industry’s environmental footprint due to its use of raw materials. We find the carbon footprint of the entire production process for cigar products to be 383.59 kg CO2 eq. Based on our findings, we suggest ways to optimize cigar/cigarette factory processes to reduce carbon emissions that can help to promote sustainable development in related industries.

Life cycle assessment perspective on waste resource utilization and sustainable development: A case of glyphosate production

The growing demand for pesticide manufacturing and increasing public awareness of sustainable development, have let to urgent requirements for a refined environmental management framework. It is imperative to conduct process-based life cycle assessments (LCAs) to promote clean and environment-friendly technologies. Herein, the cradle-to-gate LCA of glyphosate production was executed as an example to investigate crucial production factors (materials or energy) and multiple environmental impacts during the production processes. Results showed that methanol caused the highest environmental damage in terms of toxicity, with a normalized value of 85.7 × 10−8, followed by coal-fired electricity in 6.00 × 10−8. Furthermore, optimized schemes were proposed, including energy improvement (electricity generated by switching from coal-fired power to solar power) and wastewater targeted conversion. Regarding the normalization results before and after optimization, the latter showed more significant results with the normalized value decreasing by 21.10 × 10−8, while that of the former only decreased by 6.50 × 10−8. This study provides an integrated LCA framework for organophosphorus pesticides (OPs) from upstream control and offers an important supplement to managing the key pollution factors and control links of the OP industry. Moreover, it reveals the positive influence of optimized schemes in facilitating cleaner production technologies, thus ultimately promoting new methodologies for resource recycling.

Adsorption Technologies for the Removal of Cytostatics in Water: A Review

One of the most common treatments for cancer disease requires the administration of cytostatics, which are very effective drugs in the elimination of cancerous cells, but are toxic for healthy tissues. After being administered to patients, they are excreted and frequently reach natural water bodies, due to their poor degradation in wastewater treatment plants (WWTPs), posing a global threat to the environment and human health. The study of proper treatment approaches for the effective removal of these hazardous drugs in WWTPs is thus a topic of concern and of utmost importance to ensure environmental integrity, resilience and sustainability. The aim of this work is to perform a comprehensive review of the application of adsorption-based processes for the treatment of aqueous matrices contaminated with cytostatics, which has never been addressed before. A detailed discussion on the operating conditions, type and concentrations of sorbents used, toxicity of the effluents and other relevant parameters is presented. This paper aims to help identify the most promising sorbents and conditions, the current knowledge gaps, and future challenges/perspectives on adsorption technologies (isolated or coupled with other processes) to tackle the problem of cytostatic fingerprints in water courses. Additionally, information concerning the implementation of these technologies from an environmental and economic (life cycle assessment) perspective is given.

Comparison of three typical lithium-ion batteries for pure electric vehicles from the perspective of life cycle assessment

Comparison of three typical lithium-ion batteries for pure electric vehicles from the perspective of life cycle assessment

Understanding the environmental impacts of large-scale cellulose nanocrystals production: Case studies in regions dependent on renewable and fossil fuel energy sources

Favorable functional properties of cellulose nanocrystals (CNCs) in several end-use applications as well as its ‘green’ credential as a bio-based material, stimulate significant interest in scaling up the manufacture of CNCs. As in any other process, there exist several design options for the overall process and decisions on adoption of a specific plant configuration should be based on the economic as well as the environmental data, preferably from the life cycle assessment (LCA) perspective. In this study we establish a benchmark LCA of a conceptual large-scale CNC manufacturing process based on sulfuric acid hydrolysis. We then employ the benchmark process model to explore several plant configurations under different acid recycling scenarios and targeting two different CNC materials, revealing key findings: (1) without acid recycling environmental impacts are dominated by input materials; (2) introducing acid recycling shifts environmental impacts from input materials to energy consumption: thus, complete acid recycling requires ∼ 14 times more energy; (3) based on the LCA study we recommend optimizing plant configuration through partial acid recycling for a balance between materials and energy consumption. Regions with abundant low-carbon energy, like Quebec and Sweden, favour high acid recycling, while fossil-dominated regions benefit from limited acid recycling. This study provides benchmark values of LCA impacts of CNC manufacture, which could be used for the assessment of carbon footprint and other environmental metrics of final products manufactured from CNCs.

Life cycle assessment of a marine biorefinery producing protein, bioactives and polymeric packaging material

Abstract Purpose Algal research has been dominated by the use of marine biomass (mainly microalgae) as feedstock in the production of second-generation biofuels, albeit with limited economic success. A promising alternative strategy is the valorisation of seaweed (macroalgae), with the cascaded extraction of its high-value components, as well as lower-value components further downstream, under the ‘biorefinery concept’. The goal of this study was to assess the environmental performance of one such marine biorefinery situated in the UK. Methods Attributional life cycle assessment (LCA) was conducted on a hypothetical marine biorefinery coproducing fucoidan, laminarin, protein and alginate/cellulose packaging material (target product), from cultivated Saccharina latissima. The functional unit was the production of 1 kg of packaging material. A total of 6 scenarios were modelled, varying in coproduct management methodology (system expansion, mass allocation or economic allocation) and applied energy mix (standard or green energy). Sensitivity analysis was also conducted, evaluating the systems response to changes in allocation methodology; product market value; biomass composition and transport mode and distance. LCA calculations were performed using OpenLCA (version 1.10.3) software, with background processes modelled using the imported Ecoinvent 3.6 database. Environmental impacts were quantified under ReCiPe methodology at the midpoint level, from the ‘Heirarchist’ (H) perspective. Results and discussion The overall global warming impacts ranged from 1.2 to 4.52 kg CO2 eq/kg biopolymer, with the application of economic allocation; 3.58 to 7.06 kg CO2eq/kg with mass allocation and 14.19 to 41.52 kg CO2eq/kg with system expansion — the lower limit representing the instance where green electricity is used and the upper where standard electricity is employed. While implementing the green energy mix resulted in a 67% reduction in global warming impacts, it also incurred a 2–9 fold increase in overall impacts in the categories of terrestrial acidification, human non-carcinogenic toxicity, land-use and terrestrial ecotoxicity. Economic allocation resulted in burden shifting most favourable to the packaging material pathway. Conclusions This study demonstrates that the road to environmental optimisation in marine biorefineries is fraught with trade-offs. From the perspective of LCA — and by extension, the eco-design process that LCA is used to inform — when evaluating such product systems, it serves to strike a balance between performance across a broad spectrum of environmental impact categories, along with having consideration for the nature of energy systems incorporated and LCA methodological elements. Graphical Abstract

Process efficiency and life cycle assessment of novel waste-derived Chl/TiO2 photocatalyst for rhodamine B removal

Visible-light photocatalysis is a promising approach toward cleaner production and environmental impact reduction. Dye sensitization of TiO2 nanoparticles with chlorophyll (Chl) pigments is a potential alternative for the improvement of photocatalysis efficiency but must be modified for higher activity in visible light. Herein, a novel and green Chl/TiO2 photocatalyst was constructed for rhodamine B removal using the TiO2 waste of the gas refinery Clause process, sensitized with extracted chlorophyll from orange tree leaf pigments. The effects of pH, pigment ratios, photocatalyst dosage, and temperature on the Chl/TiO2 photocatalyst performance accompanied by its environmental impacts were investigated. The results indicated that the pristine TiO2 before sensitization could degrade ~30 % of rhodamine B while the photocatalytic activity was enhanced to ~98 % after modification by 0.6 wt% chlorophyll pigments. The optimum conditions were achieved at 25 mg/l Chl/TiO2, pH = 4, and 50 mg/l rhodamine B after 2 h irradiation of visible light (LED lamp 50 W). Recycling studies showed a rhodamine B decolorization of 90 % after 5 cycles and demonstrated that Chl/TiO2 is a promising heterogeneous photocatalyst for the long-term removal of dyes from wastewater. The Chl/TiO2 followed the pseudo-first-order kinetic model and illustrated negative impacts on global warming (6.3 kg CO2) and terrestrial ecotoxicity (10.7 kg 1.4-DCB) from a life cycle assessment (LCA) perspective, originating from electricity consumption and acetone. Summing up, the present study offers a new and eco-efficient photocatalyst to facilitate wastewater treatment in real-world applications and gives perspectives to manage its long-term concern.

Regional management options for floating marine litter in coastal waters from a life cycle assessment perspective

PurposeDespite the increasing number of publications focusing on the management of marine plastic debris, most research is carried out using an upstream perspective, focused on sources and pathways of marine litter accumulation, as well as actions to prevent plastics from entering the environment. The aim of this paper is therefore to investigate a combination of waste management technologies for marine litter in order to inform decision-making on environmental impact hotspots at regional level.MethodA study of the North Sea German Bight identified existing technologies suitable for the collection and treatment of floating marine debris including, recycling of plastics, mechanical biological treatment (MBT), and landfilling. Processing data for reported marine litter compositions in the region are used to inform the modelling of a waste management strategic plan (WMSP) aimed at valorising various fractions. Hence, collected floating marine litter is separated into derelict fishing gear (DFG) and mixed marine litter (MML) which are sent respectively to a recycling plant for plastic granulates production and to an MBT plant for recovery of metals and electricity generation. Environmental impacts of the WMSP are evaluated using the Life Cycle Assessment methodology and compared with incineration considered as the prevalent waste scenario.Results and discussionAs partly expected, the LCA results reveal higher environmental performance in all impact categories for the incineration scenario. In particular, the WMSP contributes to Global Warming Potential (GWP) more than 10 orders of magnitude less than the incineration scenario. However, the breakdown of results related to the WMSP indicates the highest contribution to environmental impacts attributed to electricity and heat generation from refused-derived fuel and emissions at the combined heat and power plant, as well as electricity and diesel consumption. Lowest contributions are attributed to the recycling plant. The sensitivity analysis revealed low contributions to GWP if plastic debris such as DFG is diverted to recycling while toxicity-related categories are improved by efficient metal and energy recovery at the MBT plant.ConclusionFindings of this study show that no single treatment method is enough rather a combination of different treatment pathways should be designed considering the composition and properties of accumulated marine litter in a specific area. However, recovering plastic litter and diverting useful materials from waste-to-energy to recycling improve the environmental performance. Reviews suggest inclusion of valorisation treatment options in future WMSPs of marine litter such as plastic-to-fuel technologies.

Bacteria-based self-healing concrete− A life cycle assessment perspective

A life cycle assessment (LCA) was utilised to evaluate the environmental impact of bacteria-based self-healing concretes (BBSHCs), where non-ureolytic bacterial endospores are encapsulated in porous calcium silicate granules. Findings reveal that 1 m3 of BBSHC has an overall 85% higher environmental impact than equivalent conventional concrete, primarily due to calcium nitrate and polyvinyl acetate. Furthermore, BBSHC has a 36% larger embodied carbon footprint (120 kg CO2 eq) and a 51% larger water footprint (260 L). However, by selectively incorporating BBSHC in specific areas of reinforced concrete structures, leveraging its inherent self-healing properties to deliberately allow wider crack widths, and consequently, reduce the amount of non-structural steel needed to control early-age cracking, sustainability improvements ranging from 12% to 50% can be achieved depending on the impact category. In this regard, a BBSHC-structure can potentially save up to 51 kg CO2 eq per m3.