Impact Assessment Methods Research Articles

Enhancing life cycle assessment for reversible ground-coupled heat pump systems through dynamic analysis

Ground-coupled heat pump (GCHP) systems can provide comfortable indoor environments, but also inevitably contribute to greenhouse gas emissions and other impacts on human health, ecosystems, and resources. Life cycle assessment (LCA) methodology has been widely adopted to estimate the environmental impacts associated with GCHP systems, with operational electricity consumption being the largest contributor among most categories. Given the data-intensive nature of LCA, operational electricity consumption should be prioritised to refine the accuracy of LCA results. Previous studies, however, have relied on static COP (Coefficient of Performance) and annual average data to obtain the environmental impacts and have disregarded the effect of long-term performance degradation caused by building thermal load imbalances. In this paper, to bridge this research gap, a dynamic operational environmental impact assessment (DOEIA) method was proposed to improve the precision of LCA results by incorporating higher temporal resolution data of electricity mix and real-time performance modelling of the reversible GCHP system. Impacts of different temporal resolutions (i.e. monthly, trimestral, and annual) on the accuracy of LCA results was examined and the operational performance degradation resulting from imbalanced building heating and cooling loads was considered. Results demonstrate that while performance degradation effects are evenly distributed across impact categories, gaps due to temporal resolutions vary significantly between different categories. Subsequent analysis of spatial variations in the latter further emphasises the importance of accounting for higher temporal resolutions. Finally, life cycle impact assessment (LCIA) results for reversible GCHP systems in different locations were obtained with the support of DOEIA method and the results underscore the necessity of a cleaner energy mix. The proposed DOEIA method can be applied to other energy systems for comparative analyses. It is replicable in other countries and regions and therefore is expected to provide methodological guidance for future decision-makers.

Estimated mortality attributable to the urban heat island during the record-breaking 2022 heatwave in London.

The United Kingdom experienced its most extreme heatwave to date during late July 2022, with maximum air temperatures exceeding 40 °C recorded for the first time in history on July 19th. High ambient temperatures have been statistically shown to lead to increased mortality. Higher nighttime temperatures that occur in more urbanised areas, called the urban heat island (UHI), may contribute to the mortality burden of heat. In this study, we applied health impact assessment methods with advanced urban climate modelling to estimate what contribution the UHI had on the mortality impact of the 10-25 July 2022 heatwave in Greater London. Estimated mortality due to heat and due to the UHI were compared with estimated mortality due to air pollution in the same period, based on monitored concentrations. We estimate that of the 1773 deaths in Greater London in this period 370 (95% confidence interval 328-410) could be attributed to heat. We estimate that 38% of these heat-related deaths could be attributed to the UHI. In the same period is estimate deaths attributable to PM2.5 were 20.6 (10.4-30.8) and to ozone were 52.3 (95% confidence interval 18.6-85.2). Despite not contributing to the record-breaking maximum air temperature observed during this period, the UHI may have contributed to the heatwave's mortality burden through raised nighttime temperature. While air pollutant concentrations were elevated during the period, deaths attributable to air pollution were relatively few compared to deaths attributable to heat.

Weighting factors for LCA—a new set from a global survey

PurposeThis paper provides global weights (weighting factors) for the three endpoint impact categories (areas of protection (AoPs)) of the United Nations Environment Programme (UNEP) Life Cycle Initiative’s “Global Guidance for Life Cycle Impact Assessment Indicators and Methods” (GLAM) project, namely human health, ecosystem quality, and natural resources and ecosystem services.MethodsA discrete choice experiment (DCE) was conducted to elicit the preferences of respondents on the GLAM AoPs, and they were then used to calculate the respective weights. Responses were obtained from a subset of countries pertaining to each income level defined by the World Bank (i.e. low, lower-middle, upper-middle, and high). The adimensional (between 0 and 1) weights were derived using two different approaches: econometric and multiple criteria decision analysis (MCDA). The econometric approach obtained weights by transforming the estimated preference parameters from a multinomial logit model. The MCDA approach obtained weights representing the vectors that best reconstitute the choices of each individual, using linear programming to fit an additive value function.ResultsWhen considering responses from all income groups, the weights from the econometric approach are 0.42, 0.31, and 0.26 for human health, ecosystem quality, and natural resources and ecosystem services, respectively. Following the same order for the AoPs, the weights from the MCDA approach are 0.41, 0.32, and 0.27. For high-income countries, ecosystem quality has the highest weight; for upper-middle-income countries, ecosystem quality and human health have the same weights using the econometric approach, while in the MCDA approach, human health is weighted higher than ecosystem quality. For the two lower income country groups, the priority is given to human health with both approaches. Recommendations for the use of these weights are also provided, as well as a comparison with other existing weights.ConclusionThe two methods obtained similar weights overall, although with some differences when disaggregated by income groups. The weights proposed in this paper are suitable for decision-makers or users who want to use survey-derived weights for endpoint-based LCA when using the AoPs of GLAM. These weights can be used in projects where the decision-makers do not want to or have no resources to identify a set of weights themselves, or when decision-makers are not involved.

Enhancing the building resilience in a changing climate through a passive cooling roof: A case study in Camas (Seville, Spain)

Renovating buildings is a crucial mission for the coming decades to combat energy inefficiencies and produce a resilient building stock. The inefficient thermal envelope has significant implications for occupants, especially for families lacking the financial resources to maintain a healthy and comfortable indoor environment. In scenarios where households cannot afford or utilize HVAC systems and high temperatures are more frequent, building retrofits should prioritize reducing heat loss in winter and passively lowering indoor temperatures in the cooling season. This work introduces a new solution to enhance the liveability of a social housing building in southern Spain by integrating a double-skin roof with a conventional retrofit strategy, which incorporates passive cooling techniques – night ventilation and an evaporative cooling system – for effective heat dissipation based on available commercial solutions. An extensive monitoring campaign was conducted over three years to evaluate the thermal comfort of occupants and the risk of overheating in naturally conditioned buildings before and after renovation following two impact assessment methods: real-time data-based and simulation-based. The real-time data-based method compared the indoor conditions of a dwelling with a conventionally retrofitted roof to one with a double-skin roof, indicating that the dynamic roof maintains a ceiling temperature lower than the air temperature throughout the summer while the conventional roof acts as a heating surface. On the other side, the simulation-based method compared the observed indoor conditions with a double-skin roof enabled during 2023 to the initial stage and a double-skin roof disabled scenario, using calibrated building energy models. The natural cooling roof solution almost eliminates the overheating events, leading to a reduction of 94.1% and 76.9% in discomfort degree-hours compared to the initial stage according to the ASHRAE adaptative and Fanger comfort models, respectively. Additionally, the results indicate that conventional retrofits can increase the risk of overheating when a cooling system is not considered. Integrating a cool roof solution requires only an extra implementation cost of 31€/m2 compared to a conventional solution, having an operational cost that represents less than 3% of the minimum monthly income in the social housing district.

Life cycle assessment of recycling metallised food packaging plastics using mechanical, thermal and chemical processes

Single treatment of metallised food packaging plastics waste (MFPW) has shown disappointing results with recycling rate <20 % due to its complex structure consisting of 10 % aluminium (Al) and 90 % mixed plastic films made of PE, PP, PS, PET, etc. Besides, it is generating many emissions and residues that must be landfilled making it difficult to integrate them into the circular economy. Therefore, a multi-stage recycling (MSR) approach has recently been developed using several sequential mechanical, thermal and chemical processes to recover energy and Al from MFPW with additional revenue for recycling plant operators. The thermal treatment helps to decompose the plastic fraction into wax or oil, gaseous, and solid residue (SR) composed of Al and coal, while the mechanical process can be used as a pre-treatment of MFPW feedstock and SR. Finally, the chemical treatment (leaching and functionalization) can be used to extract Al from SR and to refine coal into carbon microparticles (CPs), respectively. In order to investigate the environmental performance of the proposed MSR system, this research was developed. The investigation was performed using SimaPro life cycle analysis (LCA) tool according to ISO 14040/44 Standards and the impact assessment method is ReCiPe 2016. Five different scenarios were proposed in the constructed LCA layout, namely, conversion of MFPW to a) wax and gas (pyrolysis), b) wax, gas, and aluminium chloride (AlCl₃) (pyrolysis and leaching), c) wax, gas, AlCl₃, and CPs (pyrolysis, leaching, and functionalization), and d) oil, gas, AlCl₃, and CPs (catalytic pyrolysis, leaching, and functionalization). Besides, the oil produced from catalytic pyrolysis is used for generation of electricity (scenario e). The results showed that wax and gas recovery scenario (a) has better environmental potential and environmental benefits compared to incineration practice. The results did not change much after extraction of Al and CPs (scenario b, c), with a few increasing by 2–4% in the total score. While a lot of environmental burdens from upgrading and utilization (Scenario d, e) were recorded, reaching 79 % due to the huge amount of the catalyst was used. Thus, MSR systems have bigger environmental benefits, however, the chemical and catalytic processes still need to be further improved to reduce the effect of terrestrial acidification.

Environmental Performance of Ammonia Production in Indonesia using Life Cycle Assessment Approach

Ammonia is a fundamental component in fertilizer and chemical manufacturing processes around the world, but its production is a significant contributor to CO2 emissions in chemical industry. Implementation of carbon capture utilization and storage (CCUS) offers an alternative decarbonisation strategy to mitigate CO2 emissions in ammonia production. This study assesses the environmental performance of ammonia production through life cycle assessment (LCA) methodology. Environmental impacts are calculated using openLCA software with various impact assessment methods, including CML IA Baseline, Impact 2002+, Recipe 2016 Midpoint (H), and AWARE. The study scope encompasses the cradle-to-grave analysis, from the extraction of raw materials and transportation to ammonia production, main processes, distribution, and consumer product consumption, with a declared unit of 1-kg ammonia product. Our findings showed that CO2 removal and Power Plant in core processes in the core process as the most significant contributors to Global Warming Potential. Therefore, sensitivity analysis was conducted by reducing CO2 emission by 10% and 70% through CCUS implementation. The results showed that the CCUS implementation could reduce Global Warming Potential by up to 43%.

Holistic regulatory framework for distributed generation based on multi-objective optimization

Regulatory changes associated with distributed generation have occurred in several countries (e.g., the USA, Germany, the UK, and Australia). However, there is a lack of robust and holistic analytical models that can be used to implement the best regulatory framework among possible options. In this context, the present paper proposes a cutting-edge regulatory framework for distributed generation based on multi-objective optimization, taking into account socioeconomic (socioeconomic welfare created by the regulated electricity market and electricity tariff affordability) and environmental (global warming potential) indicators. Such indicators are modeled primarily based on the optimized tariff model (socioeconomic regulated electricity market model), Bass diffusion model (forecasting model of distributed generation deployment), and life cycle assessment (environmental impact assessment method). The design variables are assumed to be the regulated electricity tariff and remuneration of the electricity injected into the grid over the years. First, the proposed methodology is applied to fifteen large-scale Brazilian concession areas with a significant deployment of distributed generation assuming two approaches, a multi-compensation scenario, where the compensation is set individually for each concession area, and a single-compensation scenario, where the compensation is set equally for all concession areas. Then, the optimal solutions are compared to Ordinary Law 14300, which is a recently implemented regulatory framework for distributed generation in Brazil. Results demonstrate that Ordinary Law 14300 is a dominated or non-optimal solution since it is not located on the optimal Pareto frontiers for any of the assessed concession areas. Assuming the Euclidian knee points, benefits averaging 33% and 15% were achieved in terms of electricity tariff affordability for the multi and single-compensation scenarios, respectively, with small losses of 8% and 3% in terms of socioeconomic welfare and global warming potential. Though the proposed methodology is applied in the Brazilian context, it can also be applied to other countries with regulated electricity markets; thus, it is expected to be valuable for researchers, government institutions, and regulatory agencies worldwide.

Disentangling marine plastic impacts in Life Cycle Assessment: Spatially explicit Characterization Factors for ecosystem quality

Inputs of persistent plastic items to marine environments continue to pose a serious and long-term threat to marine fauna and ecosystem health, justifying further interventions on local and global scales. While Life Cycle Assessment (LCA) is frequently used for sustainability evaluations by industries and policymakers, plastic leakage to the environment and its subsequent impacts remains absent from the framework. Incorporating plastic pollution in the assessments requires development of both inventories and impact assessment methods. Here, we propose spatially explicit Characterization Factors (CF) for quantifying the impacts of plastic entanglement on marine megafauna (mammals, birds and reptiles) on a global scale. We utilize Lagrangian particle tracking and a Species Sensitivity Distribution (SSD) model along with species susceptibility records to estimate potential entanglement impacts stemming from lost plastic-based fishing gear. By simulating plastic losses from fishing hotspots within all Exclusive Economic Zones (EEZs) we provide country-specific impact estimates for use in LCA. The impacts were found to be similar across regions, although the median CF associated with Oceania was higher compared to Europe, Africa and Asia. Our findings underscore the presence of susceptible species across the world and the transboundary issue of plastic pollution. We discuss the application of the factors and identify areas of further refinement that can contribute towards a comprehensive assessment of macroplastic pollution in sustainability assessments. Degradation and beaching rates for different types of fishing gear remain a research gap, along with population-level effects on marine taxa beyond surface breathing megafauna. Increasing the coverage of impacts specific to the marine realm in LCA alongside other stressors can facilitate informed decision-making towards more sustainable marine resource management.

A Novel Multiperspective and Multistakeholder Approach to Event Impact Measurement: Synthesizing the Triple Bottom Line

Due to the increasing number of events and the complexity of the relationships and synergies between the stakeholders involved in the events and the environment there is a need to understand the contribution of events to the area where they are hosted. This article aims to develop an innovative impact assessment system that allows the effects of the event to be assessed from a global sustainability perspective via a multistakeholder approach and tries to solve the problems of comparability and commensurability raised by integrating economic, sociocultural, and environmental impacts. This novel impact assessment method creates an ad hoc synthetic index unique for each event. The impact categories are aggregated and weighted according to the specific realities of the region. This theoretical contribution involves measuring event impacts through a multiperspective and multistakeholder analytical methodology, allowing the effects to be more efficiently assessed and compared in monetary terms.

Impact assessment methods for teaching activities on sustainable development goals in higher education institutions: A case study from a Bosnian university

This study explores various approaches for assessing the impact of teaching activities on Sustainable Development Goals (SDGs). In addition to the well-known keyword search method, the study also introduces innovative methods utilizing text similarity algorithms, specifically Jaccard and Cosine algorithms. The performances of the traditional keyword search method and the proposed text similarity algorithms are then compared with the results obtained from a self-identification study conducted among the academic staff within the case study context. The strengths and weaknesses of each method are also discussed, aiming to contribute to a comprehensive understanding of impact assessment methodologies in the context of SDGs in education.

Adapting an environmental impact assessment method for open pit mines in Myanmar: A modified semi-mathematical Folchi approach

Since 1970, the global adoption of Environmental Impact Assessment (EIA) has fostered the development of multiple EIA methodologies, ranging from sample techniques to scientific approaches, for assessing environmental impacts. These methodologies encompass diverse models such as Ad hoc, matrices, checklist, network, overlay, mathematical, simulation, and dispersion models. Among these, the Folchi method is one of the quantitative matrix methods, assigning magnitudes to each impacting factor based on different possible scenarios. In this method, a matrix consisting of weighting factors is systematically utilized to quantify and standardize the effect of each impacting factor on various environmental components. Myanmar, as a developing nation that has recently implemented EIA practices, has encountered significant challenges in the realm of EIA, particularly concerning methodologies for impact evaluation, assessment, and the formulation of effective mitigation measures for various development projects. To address these challenges, this study introduces an adapted semi-mathematical Folchi EIA method, demonstrating its application in open-pit mines across Myanmar. Adjustments were made to integrate domestic environmental guidelines and EIA procedures, often overlooked in previous studies. The assessment of impact magnitude prioritizes sensitivity, project type and size, and pollution thresholds. Additionally, the correlation weights (nil, minimum, medium, maximum) between impact factors and environmental components were also adjusted based on the project's nature and regional conditions. The findings of this study revealed both positive and negative environmental impacts associated with the four case study mines. Decision-makers and stakeholders can utilize this approach in decision making process, advancing sustainable development. With suitable adaptation, this approach can facilitate a rapid and comprehensive assessment of diverse environmental and social impacts associated with various development projects in the country.

Life cycle assessment for the land application of food processing wash-water and solid residuals.

A life cycle assessment (LCA) study was completed to understand the environmental impacts associated with the land application of wastes produced from rural food-processing operations for final disposal. The system boundaries for the two comprised scenarios included the storage of the produced non-agriculture source material (NASM), transportation to an applicable location, land application of the NASM, and the impacts of the final emissions to the soil and groundwater for a full year. The Tool for the Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) v2.1 was selected as the impact assessment method. Furthermore, SimaPro 8.0.4.26 was the LCA model version that was used with all the databases included. Overall, the LCA study showed that the most significant environmental impacts associated with the disposal process resulted from carcinogenic and eutrophication emissions. The component that contributed the most to carcinogenic impacts was found to be from the material required to create the concrete storage tank. Additionally, eutrophication was identified to be a potential significant impact, if proper setback requirements are not followed for the NASM material. Results of the study look to inform stakeholders about the benefits and risks encountered from NASM disposal. PRACTITIONER POINTS: Life cycle assessment was completed on a representative NASM disposal system using land application. Concrete tank used for storage of NASM had the most significant impact in carcinogenic emissions. Eutrophication impacts were the second most significant impact behind carcinogenic emissions.

Predicting the Global Extinction Risk for 6569 Species by Applying the Life Cycle Impact Assessment Method to the Impact of Future Land Use Changes

Land use change is considered to be one of the key direct drivers of ecosystem erosion and biodiversity loss. The Life Cycle Impact Assessment (LCIA) serves as a robust tool for environmental impact assessment, featuring an advanced framework and indicators for assessing global biodiversity loss. In this research, we utilized the Species Distribution Model (SDM) to evaluate 6569 species across five taxonomic groups. We simulated habitat change and losses induced by land use changes under sustainable future scenarios from the present to 2100. This enables us to assess spatial extinction risks based on shifts in the global distribution of species. Our findings reveal a global biodiversity extinction risk of approximately 4.9 species/year, equivalent to an extinction rate of 745.9 E/MSY. Notably, higher-risk hotspots have been identified in regions such as South America, South Australia, and New Zealand. Although future sustainable scenarios involving land intensification may mitigate the biodiversity extinction rate, the objective of reaching 10 E/MSY by the end of this century remains a distant goal. By providing a more rational basis for biodiversity loss, the indicators of spatial extinction risk demonstrate the advantage of effectively reflecting regional characteristics.

Towards Sustainable Shrimp Farming: Life Cycle Assessment of Farming Practices at the Less Favorable Areas of Yogyakarta's Southern Coast

The objectives of this study were to assess the potential environmental impacts that could be utilized to describe the current state of shrimp farming and propose alternative strategies for its management. Life Cycle Assessment (LCA) was held based on stages goal and scope, life cycle inventory, life cycle impact assessment, and interpretation by using SimaPro v.9.3.0.3 software and CML IA baseline V3.07 impact assessment method. The findings of this study demonstrated that super intensive shrimp farming had a lower potential environmental impact than intensive farming. The study indicated that super intensive shrimp farming produces a lower abiotic depletion potential (ADP), global warming potential (GWP), marine aquatic ecotoxicity potential (MTP), acidification potential (AP), and eutrophication potential (EP) than intensive farming. Potential environmental impact can be minimized by choosing a more environmentally friendly source of electrical energy and pond lining material and increasing the efficiency of the use of electricity and feed.

Microplastic aquatic impacts included in Life Cycle Assessment

Although Life Cycle Impact Assessment (LCIA) methods assess a wide range of environmental impacts, ecological impacts of plastic pollution are not commonly included. Here, characterization factors of Polypropylene (PP), Low density polyethylene (LDPE) and Polyethylene Terephthalate (PET) microplastics were assessed. Fate was assessed through the multimedia fate model Simplebox4Plastics. Ecological effects were based on species sensitivity distributions. Macroplastic impacts were included though a conversion fraction. The characterization factors were included in ReCipe2016 method and applied to two consumer packaging films to show the relevance of including plastic pollution in LCAs. Plastic losses were assessed using material flow analysis. The freshwater and marine ecotoxicity midpoint indicators were dominated by plastic pollution impacts, whilst these impacts were limited on ecosystem quality as endpoint. Extending this methodology to additional polymers and additional methodological developments will help to obtain a more complete picture of plastic pollution in LCA and to identify effective mitigation options.

Comparative study of traditional and DNA-based methods for environmental impact assessment: A case study of marine aggregate extraction in the North Sea

Environmental impact assessments of marine aggregate extraction are traditionally conducted based on morphological characteristics of macrobenthos, which is time-consuming, labour-intensive and requires specific taxonomic expert knowledge. Bulk DNA metabarcoding is suggested as a promising alternative. This study compares the traditional morphological and the bulk DNA metabarcoding method to assess the impact of sand extraction activities on three sandbanks in the Belgian North Sea. Substantial differences in the detected species were observed between methods: Abundant and/or large macrobenthos species were detected by both methods, while small species or species with an exoskeleton were usually only detected by the morphological method. Taxa uniquely detected by bulk DNA metabarcoding could be explained by specimens identified at a higher taxonomic level by morphology, or by specimens with very low read numbers, probably representing species missed in the morphological sorting process, DNA traces on the specimens or false positives during PCR amplification efficiency. Despite the difference in detected species, comparable alpha and beta diversity patterns were observed by both methods, indicating that bulk DNA metabarcoding can effectively detect the overall ecological changes associated with sand extraction. We further demonstrate that bulk DNA metabarcoding reduces sample processing both in time (44 % faster) and cost (26 % cheaper) compared to the morphology-based identification. However, biomass quantification remains challenging for bulk DNA metabarcoding since of the ten most abundant genera, only two genera (Echinocardium and Ophelia) showed a significant positive correlation between biomass and read numbers. Additionally, bulk DNA metabarcoding does not provide information on life stages or size of the identified specimens. As such, our results underpin the complementary nature of both methods, wherein DNA-based analyses allow for rapid detection of community changes (as similar patterns in alpha and beta diversity and biotic index were observed), while morphology-based analyses provide additional information on e.g. secondary production (biomass) and size composition. We show how the strengths of both methods can be combined to assess the impact of sand extraction.

Environmental Impact Assessment of a 1 kW Proton-Exchange Membrane Fuel Cell: A Mid-Point and End-Point Analysis

Proton-exchange membrane fuel cells (PEMFCs) are highly regarded as a promising technology for renewable energy generation; however, the environmental burden in their life cycle is a subject of concern. This study aimed to assess the environmental impact of producing a 1 kW PEMFC by a well-detailed cradle-to-gate evaluation, using mid-point and end-point impact assessment methods. The environmental impacts are related to the extraction of raw materials, consumption of energy, and transportation processes. Mid-point analysis shows that raw materials extraction and processing have a significant share in some impacts, including freshwater eutrophication, human carcinogenic toxicity, and terrestrial acidification. On the other hand, the energy consumed in fuel cell production plays a significant role in the impact categories of fossil resource depletion and global warming. The highest impact is attributed to the human health end-point analysis (0.000866 DALY), followed by the damage to ecosystems (1.04 × 10−6 species/yr) and resources (USD2013 6.16844). Normalization results further strengthen the importance of human health impacts and the necessity to solve problems regarding toxicity. The results of this work can provide directions toward enhancing the environmental sustainability of PEMFC technology and present a case for adopting a holistic approach to sustainability by looking across the life cycle of the technology.

Characterizing Freshwater Ecotoxicity of More Than 9000 Chemicals by Combining Different Levels of Available Measured Test Data with In Silico Predictions.

Ecotoxicological impacts of chemicals released into the environment are characterized by combining fate, exposure, and effects. For characterizing effects, species sensitivity distributions (SSDs) estimate toxic pressures of chemicals as the potentially affected fraction of species. Life cycle assessment (LCA) uses SSDs to identify products with lowest ecotoxicological impacts. To reflect ambient concentrations, the Global Life Cycle Impact Assessment Method (GLAM) ecotoxicity task force recently recommended deriving SSDs for LCA based on chronic EC10s (10% effect concentration, for a life-history trait) and using the 20th percentile of an EC10-based SSD as a working point. However, because we lacked measured effect concentrations, impacts of only few chemicals were assessed, underlining data limitations for decision support. The aims of this paper were therefore to derive and validate freshwater SSDs by combining measured effect concentrations with in silico methods. Freshwater effect factors (EFs) and uncertainty estimates for use in GLAM-consistent life cycle impact assessment were then derived by combining three elements: (1) using intraspecies extrapolating effect data to estimate EC10s, (2) using interspecies quantitative structure-activity relationships, or (3) assuming a constant slope of 0.7 to derive SSDs. Species sensitivity distributions, associated EFs, and EF confidence intervals for 9862 chemicals, including data-poor ones, were estimated based on these elements. Intraspecies extrapolations and the fixed slope approach were most often applied. The resulting EFs were consistent with EFs derived from SSD-EC50 models, implying a similar chemical ecotoxicity rank order and method robustness. Our approach is an important step toward considering the potential ecotoxic impacts of chemicals currently neglected in assessment frameworks due to limited test data. Environ Toxicol Chem 2024;43:1914-1927. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Performance modification of an acid gas incinerator to reduce atmospheric pollutants impact: Energy management, HAZOP and LCA analyses

In today's industrial landscape, energy management, process modification, and reduction of atmospheric concentrations of pollutants and safety risks have become paramount. This focus is driven by the need to address environmental concerns, economic efficiency, and the global energy and climate change crisis. In gas refineries, incinerators are widely used to convert deadly and environmentally polluting acid gases into less hazardous gases. Therefore, improving incinerator performance can significantly impact environmental, economic, and energy aspects. According to the results of an energy management study at the domestic gas processing plant, the acid gas incineration unit was identified as a significant energy use. Therefore, based on the effects of the performance of this incinerator from environmental and energy points of view, the mentioned unit was prioritized for modification in this work. For this purpose, incinerator performance was assessed using Promax simulation, and Hazard and Operability (HAZOP) analysis was employed to identify potential hazards. The simulations revealed that acid gas residence time was 0.81s, longer than the 0.6s initial design with the damper in place. This suggests damper removal is feasible. Removing the damper reduces residence time and lowers incinerator temperature, especially during startup. Therefore, temperature was considered as the keyword in the HAZOP study, and a number of recommendations were proposed to eliminate or mitigate the risks of system modification. Furthermore, the assistance of results obtained from energy management based on ISO 50001:2018 standards confirm improvements in energy efficiency and fuel consumption, which have positive economic and environmental impacts. Moreover, the study employs a Life Cycle Assessment (LCA) approach using SimaPro Software 9.5.0.1 and the CML-baseline method (Centrum voor Milieukunde Leiden) for environmental impact assessment. The results reveal that, across ten environmental impact categories, the modified project exhibits significantly reduced environmental impacts compared to its original state.

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.