Development of environmental impact assessment methods for marine sourced products

To sustain the needs of growing world population, seas and oceans are becoming heavily exploited. Initially exploited for food and transportation, offshore marine areas are nowadays supplying energy and minerals. Whilst the extraction of terrestrial natural resources led to major environmental consequences (i.e. biodiversity loss), it is crucial to ensure the global environmental sustainability of marine products on their entire life cycle. Life Cycle Assessment (LCA) methods have the potential to provide such information and to identify hotspots of environmental impacts in the value chain of the product under analysis. At the endpoint level, LCA results consider impacts on three areas of protection (AoP): human health, ecosystem quality and natural resources. However, LCA methods have been traditionally applied to industrial processes and thus, are limited to include site-specific aspects (e.g. disturbance of the local ecosystem) in the scope of the assessment. The application of LCA to assess the environmental sustainability of marine products including ecosystem-specific life cycle impact assessments (LCIAs) in the evaluation of impacts belonging to the three AoP. Moreover, quantitative data on mass and energy flows associated to the entire life cycle of the products (production / extraction of raw materials and their processing to final commodities) are required to perform global environmental sustainability assessments. The overall objective of this PhD is to reinforce LCA capacity to assess the global sustainability of marine products. Two operational frameworks are proposed to include site-specific aspects related to the sourcing of marine raw materials, and data related to the processing of wet biomass are provided. In this way, the evaluation of the global environmental sustainability of marine products through LCA will be more inclusive and meaningful for comparative assessments with terrestrial alternatives. The PhD starts with a general introduction (Chapter 1) divided into four sections. First, an overview of marine activities is provided. The most important marine activities in terms of economic importance are described and the concept of the industrial revolution of the seas and oceans is introduced. This refers to the growing importance of the marine-sourced materials and energy for the global economy. Indeed, the importance of the marine economy is expected to follow a two-fold increase by 2030. On a longer time horizon, the potential recovery of deep-sea minerals might significantly increase our dependence on marine commodities. The second section provides background information related to the classification of natural resources and their link with ecosystem services. Natural resources are classified according to renewability, exhaustibility and their form at the moment of extraction (biotic / abiotic). Marine natural resources are presented according to this classification and in the context of ecosystem services. Deep-sea minerals are extensively presented as they might become substantial for our economy in a near future. The ecological pressures on marine ecosystems are discussed in the third section. Direct drivers of impact caused by the marine economy are highlighted, such as the reduction of commercial fish stock size. The fourth section introduces the global concepts of LCA and the development of site-specific LCIA pathways to assess changes in local ecosystem quality, measured through biodiversity related metrics. The main limitations for global environmental sustainability assessments of marine products are exposed. The needs for site-specific marine LCIAs and further data regarding the processing of marine raw materials are highlighted. Chapter 2 quantifies trade-offs amongst seaweed farming and wild catches fisheries. Both are considered as marine natural resources and marine ecosystem services. The reduction in fisheries yields caused by the harvesting of net primary production (NPP) (i.e. seaweed) is estimated through a trophic food web approach. A site-specific LCIA framework relying on the seasonal ecosystem NPP, seaweed biomass growth and fish landings is proposed to assess the Lost Potential Yield (LPY) of the area under study. LPY are reported in terms of biomass, economic value and eco-exergy, a metric measuring the genomic complexity of the organisms. The framework is illustrated for the Greater North Sea and shows a net positive contribution of seaweed farming in terms of marine natural resources (i.e. the production of seaweed exceeds the decrease in fisheries landings for the three LPY metrics). Further research could consist in the development of additional impact pathways to NPP reduction (e.g. habitat provision) and on the consideration of ecosystem carrying capacity. The following chapter (Chapter 3) develops a site-specific LCIA framework to assess impacts of deep seafloor disturbance on regional and global biodiversity as proxy for ecosystem quality. Changes in ecosystem quality are measured through a biodiversity-related metric: the potentially disappeared fraction of species (PDF), expressing relative changes in species richness caused by the intervention. The framework builds on existing LCIAs assessing impacts on ecosystem quality from land-use (i.e. land transformation and occupation). According to existing literature, the framework identifies three kinds of impacts: transformation, occupation and permanent impacts that can be summed to obtain the total impact on regional and global ecosystem quality. The regional biodiversity impacts are first assessed and converted to global biodiversity impacts considering the vulnerability and the scarcity of the ecosystem impacted. The framework is operationalized in a case study consisting to polymetallic nodules mining in the Clarion Clipperton Fracture Zone (CCZ). Despite the very limited knowledge on benthic recovery from deep-sea mining, the framework shows consistency with existing LCA characterization models for biodiversity. The total impact on regional and global biodiversity is mostly influenced by the permanent impact on biodiversity because of the absence of recovery of a significant fraction of species. This framework can be integrated into LCA studies in order to understand the global environmental sustainability of deep-sea activities. Next to the development of additional LCIAs, the availability of detailed and transparent datasets is another challenge to assess the global environmental sustainability of marine products. Chapter 4 computes mass and energy flows associated with the harvesting and the processing of microalgae under eight biorefinery scenarios to produce lipids, proteins, energy and dried biomass. Two cell disruption methods are tested and two solvents for lipid extraction are compared. Complete flowsheets are provided for each step of the downstream processing of the raw biomass. The chapter highlights the impact of the cell disruption method on the total energy demand but also, the influence amongst downstream processes in a cascade design. Lipid extraction has influence on protein extraction, this latter improving energy production as it has a more favourable carbon to nitrogen ratio. In addition, lipids are extracted with a conventional solvent (hexane) for some scenarios and with a biobased solvent (2-methytetrahydrofuran) for other scenarios. The azeotropic distillation required for the recovery of the biobased solvent (and thus its extra energy demand) shows that solvent selection is crucial to control the total energy demand of the process, but lipid profiles will vary according to solvent properties. The last chapter (Chapter 5) consists of the conclusions and perspectives of the manuscript. Whilst the conclusions discuss the main outcomes of the three (published) research chapters (Chapter 2, Chapter 3 and Chapter 4), the perspective section opens a discussion on the requirement for an exhaustive classification of marine ecosystems. In a similar way as for the terrestrial ecosystems, such classification will facilitate the development of databases for marine ecosystem attributes and hence, the implementation of site-specific LCIAs. Furthermore, the section discusses alternatives to species richness related metrics to monitor changes in the ecosystem quality. Different types of biodiversity are defined according to the combination of biodiversity level (i.e. genetic, species, communities and landscape) and biodiversity attribute (i.e. composition, structure, function). Consequently, it is not possible to grasp the entire complexity of biodiversity through a single indicator such as species richness in LCA methods. The use of potential additional indicators for ecosystem quality and the main challenges arising from it are discussed. Finally, the discussion highlights the importance of aligning the scope of LCA studies with the descriptors used by European policy makers to assess the environmental status of marine ecosystems (under the Marine Strategy Framework Directive, MSFD). It emphasizes the needs for additional marine LCIAs to consider all descriptors identified by the MSFD (11) in LCA studies of marine products. The challenge of integrating marine ecosystem services in the scope of LCA studies is considered. Because of the complexity of quantifying ecosystem services and their link with biodiversity, the use of regional biodiversity as midpoint indicator for ecosystem services is proposed. Finally, the section concludes by discussing the challenge of evaluating the total cumulative impact caused by different stressors on a given marine ecosystem. Whilst existing LCIAs do not consider interactions amongst each other, it is relevant to make use of ecological risk assessment tools to model the final ecosystem response to various disturbances occurring in parallel. To conclude, this work has emphasized two main challenges for the global environmental sustainability assessment of marine products: the implementation of site-specific LCIA frameworks and the development of datasets regarding further processing of the harvested products

Optimization and comparison of three cell disruption processes on lipid extraction from microalgae

This study reports on the optimization of the operating conditions using response surface methodology and a comparative study of three promising technologies of cell disruption (bead milling, microwaves and ultrasound) to increase the lipid extraction from Nannochloropsis oceanica, Nannochloropsis gaditana and Tetraselmis suecica. Central composite designs were used for the optimization of ultrasound and microwave processes. The performance of the cell disruption processes in breaking down microalgae cells is dependent on the strain of microalgae. Microwaves (91 °C for 25 min) were the most efficient for the recovery of lipids from N. oceanica, reaching a lipid content of 49.0% dry weight. For N. gaditana, ultrasound process (80% of amplitude for 30 min) was the most efficient in terms of lipid recovery (21.7% dry weight). The two aforementioned processes are ineffective in disturbing T. suecica whatever the operating conditions used. Only the bead milling process at low flow feed rate with 0.4 mm zirconia beads made it possible to extract 12.6% dry weight from T. suecica. The fatty acid profiles of N. oceanica and T. suecica are affected by the cell disruption process applied. The calculation of specific energy consumption has shown that this criterion should not be neglected. The choice of the most suitable cell disruption process can be defined according to numerous parameters such as the microalgae studied, the total lipid extracted, the fatty acids sought, or the energy consumption

A framework for using the handprint concept in attributional life cycle (sustainability) assessment

Handprint refers to the good society does for the environment, but this definition gives room for different interpretations. While in life cycle (sustainability) assessment (LC(S)A) its use is still at infancy, the effective communication potential of Handprint terminology gives room for increasing its application in the future. The objective of this article is to propose a framework to distinguish and classify various types of handprint, when they are intended to be used in LC(S)A studies. Building on the current structure of LC(S)A regarding the cause-effect chain, from flows to impacts, a framework to allow understanding the beneficial, adverse and net effects various flows can cause to different actors is created. Based on that, three handprint types are proposed, i.e., Direct, Indirect and Relative. These types can be subdivided into more specific/complex types of handprint, e.g., Indirect Relative Handprint (adverse). Illustrations with case studies (fictive and from literature) are used to suggest some guidance. With this proposal, a first step to consistently introduce the handprint concept into LC(S)A is achieved, but future challenges still exist (e.g., development of quantitative methods for beneficial impacts from product’s functionality, in footprint-consistent units)

Integrating ecosystem services and life cycle assessment: a framework accounting for local and global (socio-)environmental impacts

Purpose: Human activities put pressure on our natural ecosystems in various ways, such as globally through the spread of emissions or locally through the degradation of species-rich landscapes. However, life cycle assessment (LCA) studies that integrate ecosystem services (ES) are still in the minority because of intrinsic differences in data, modelling, and interpretation. This study aims to overcome these challenges by developing and testing a framework that comprehensively evaluates the (socio-)environmental impacts of human activities. Methods: LCA and ecosystem services assessment (ESA) were integrated in two different ways: (1) both methodologies run in parallel and results are combined, and (2) LCA as a driving method where ES are integrated. Because local ESA studies contain the most accurate information but will not be available for all processes in the value chain, it was necessary to advance the life cycle impact assessment method ReCiPe 2016 including three new midpoint impact categories (terrestrial provision, regulation, and cultural ES) and site-generic CFs based on the Ecosystem Services Valuation Database to account for changes in regulating, cultural and provisioning ES due to land use, for the remaining processes in the value chain. Monetary valuation is used to aggregate at the areas of protection (AoP). Results and discussion: A comprehensive LCA$_{+ES}$-ESA sustainability assessment framework is developed to account for local and global impacts due to human activities on three AoPs (natural resources, ecosystem quality, and human health and well-being), of which the results are expressed in monetary terms. The framework is able to visualize all benefits and burdens accounted for through the handprint/footprint approach. A simplified terrestrial case study on Scots pinewood shows the applicability of the proposed framework, resulting in a handprint (€$_{2022}$ 9.81E+02) which is four times larger than the footprint (€$_{2022}$ 2.31E+02) for 1 kg of wood produced. Challenges related to the framework such as data availability and database shortcomings (i.e., beyond land use) and ES interrelations are discussed. Conclusion: While classical LCA studies focus more on burdens, this framework can also take into account benefits, such as the provision of ecosystem services (or the value of the functional unit of the study). Although the integration of both LCA and ESA has been increasingly explored recently, until now no framework has been available that can incorporate results from local ESA, site-specific ESA, and classical LCA studies, which is considered highly relevant to decision-making

Prospective life cycle assessment of metal commodities obtained from deep-sea polymetallic nodules

Sustainable metal supply will be essential to achieve climate and sustainability goals (e.g., Paris agreement), for instance by providing the necessary raw materials for renewable energy infrastructure systems. The potential exploitation of mineral resources from the deep sea (e.g., polymetallic nodules) can play a major role in this supply. A holistic environmental analysis is needed, in order to consider the entire value chain of the products obtained out of deep-sea exploitation. Therefore, the objective of this study was to perform a prospective life cycle assessment (LCA) of deep-sea-sourced commodities and compare it to equivalent products obtained from terrestrial mining. It considered as reference flow one tonne of (dry) nodules, using a cradle-to-gate approach up to the final metal commodities, analyzing the delivery to the market of 10.5 kg of copper, 12.8 kg of nickel, 2.3 kg of cobalt and 311.3 kg of ferromanganese. Three environmental impact categories were analyzed, i.e., climate change, acidification and photochemical oxidant formation. Overall, onshore activities (e.g., hydrometallurgical processing) are the main hotspots for environmental impacts of metals sourced from the deep sea; offshore activities play a minor role in the value chain. While photochemical oxidant formation impacts would be similar to terrestrial alternatives, the deep-sea-sourced commodities can bring environmental gains in the order of 38% for climate change and up to 72% for acidification. As this study shows, a strategic selection of the location for onshore processing of the polymetallic nodules is key to target cleaner production, not only because of the distance from the nodules site, but especially because of the available energy mix. The results should be interpreted with care, though, due to intrinsic limitations of the LCA study, e.g., the prospective nature of this study, the limited access to terrestrial mining data, amongst others. Nonetheless, regardless the limitations a prospective LCA imposes, this study highlights some important potential benefits that commodities from deep-sea polymetallic nodules can bring to society with respect to three important environmental impacts

Identification of microalgae biorefinery scenarios and development of mass and energy balance flowsheets

The notion of bioeconomy is at the basis of recent European strategies aiming at conciliating economic growth and sustainability. Consequently, extensive research has been conducted on biobased solutions such as microalgae products. Numerous initiatives to commercialize microalgae have been launched but few of them were successful. Algae biofuel is the most obvious illustration with its promises as energy supply but faces many challenges to become economically competitive. Consequently, it was recently proposed to develop microalgae biorefineries for an optimal biomass valorisation, to dilute the overall costs within a wide range of products. Herein, the energy demand for different microalgae biorefinery scenarios is investigated and critical steps identified. Each scenario is modelled using information from literature and process engineering principles. The production of lipids, proteins, methane, fertilizers and dried biomass are considered. Once defined, the scenarios are modelled and their energy inputs are discussed. We also investigate the impact of using a biobased solvent for lipid extraction instead of a conventional one. On top of that, each scenario is assessed for two cells disruption methods. In both cases, the study starts with dewatering the growth medium of the microalgae Chlorella vulgaris (240 kg DW h−1) and ends with the recovery of the products. The results vary from 20.07 to 66.53 MJ kg−1 input DW and highlight the importance of the cell disruption method in the total energy demand. While lipid extraction presents adverse impacts on proteins extraction due to solvent recovery, proteins extraction has beneficial effects on further methane production step. Our study concludes with the comparison of microalgae biomass with soy, for proteins and lipids production, and demonstrates quantitatively that microalgae-based technologies are still inefficient compared to present alternatives. This work provides quantitative numbers for further evaluation of microalgae projects considering the current stage of the technology

Environmental performance of plastic food packaging : life cycle assessment extended with costs on marine ecosystem services

Packaging can play a substantial role in moving towards more sustainable food systems by affecting the amount of food loss and waste. However, the use of plastic packaging gives rise to environmental concerns, such as high energy and fossil resource use, and waste management issues such as marine litter. Alternative biobased biodegradable materials, such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) could address some of these issues. For a careful comparison in terms of environmental sustainability between fossil-based, non-biodegradable and alternative plastic food packaging, not only production but also food preservation and end-of-life (EoL) fate must be considered. Life cycle assessment (LCA) can be used to evaluate the environmental performance, but the environmental burden of plastics released into the natural environment is not yet embedded in classical LCA. Therefore, a new indicator is being developed that accounts for the effect of plastic litter on marine ecosystems, one of the main burdens of plastic's EoL fate: lifetime costs on marine ecosystem services. This indicator enables a quantitative assessment and thus addresses a major criticism of plastic packaging LCA. The comprehensive analysis is performed on the case of falafel packaged in PHBV and conventional polypropylene (PP) packaging. Considering the impact per kilogram of packaged falafel consumed, food ingredients make the largest contribution. The LCA results indicate a clear preference for the use of PP trays, both in terms of (1) impact of packaging production and dedicated EoL treatment and (2) packaging-related impacts. This is mainly due to the higher mass and volume of the alternative tray. Nevertheless, since PHBV has limited persistence in the environment compared to PP packaging, the lifetime costs for marine ES are about seven times lower, and this despite its higher mass. Although further refinements are needed, the additional indicator allows for a more balanced evaluation of plastic packaging

Development of potential yield loss indicators to assess the effect of seaweed farming on fish landings

In recent years, several indicators have been proposed to assess the effect of human activities on ecosystems provisioning capacity. Some of these methods focus on the Net Primary Production (NPP) available for ecosystem functioning through the comparison between the Human Appropriated Net Primary Production (HANPP) and the ecosystem's initial NPP at a given reference year. While some approaches have been proposed for marine ecosystems, most of the HANPP studies focus on terrestrial systems. This study highlights the relation between the HANPP methods and the production of natural resources in marine ecosystems. The linkage between current overfishing and future fish provisioning (ecosystem service) is well known. However, less studied before, is the relation between seaweed aquaculture and fish provisioning through the marine food web. Seaweed growth requires nutrients and light that will consequently be no longer available for natural phytoplankton production. As seaweed is periodically harvested, a fraction of the ecosystem's NPP (HANPP) is no longer available for ecosystem production. The HANPP of aquaculture reduces the ecosystem carrying capacity and thus affects commercial fish stocks. Therefore, an integrative approach is proposed in this study to assess the potential effect of seaweed farming on fish landings in the Greater North Sea. Three indicators are proposed to assess the Lost Potential Yield (LPY) in fish landings: LPYB, LPYV and LPYE, accounting respectively for reduction in biomass, monetary value and eco-exergy. For these three aspects, the LPY results remains smaller than the seaweed production, meaning that the overall natural resources balance for seaweed farming is positive