Recently, there has been more and more research on the abundance of MPs (MPs) in oceans, seas, and rivers. A lot is still uncertain about the distribution of MPs, and whether they are mainly deposited in seas & oceans, or river sediments. As global models on MP transport through rivers have only used statistical methods, we present a global riverine MP transport model based on mechanical principles. The model incorporates particle advection, settling, entrainment, and input emissions from wastewater treatment plants. The model was run for a period of 5 years, on 8 MP mixes of 15 MPs each, with the same 24 uncertainty scenarios for each MP mix (totalling 192 runs). Exported (to seas and oceans) and sedimented MPs showed a linear increase over time, while MPs suspended in the river reached steady state, but showed heavy seasonal fluctuations. Under the modelled uncertainties, after 5 years of simulation time, 76% of MPs are exported to seas and oceans and 19 % of MPs are deposited in river sediment. 5% of MPs were suspended in the water column. Major contributing areas to global MP emissions are area’s with large population densities, like Europe, North America, China & South East Asia, and India. Our work contributes to the understanding of MP flows through rivers, and could be used as a starting point for a MP material flow analysis, or as the basis for MP impact assessments. Future iterations of the model should implement man-made barriers and reservoirs, which
were not considered in the current version of the model.

The research focuses on a novel measurement-based approach to estimate the farm-specific ammonia emission potential (AEP) in the dairy sector. By measuring and evaluating the feed-manure chain, feed management strategies and manure parameters influencing AEP can be identified. Ammonia emissions from dairy farms are not only considered to be an important driver of biodiversity loss, but are also responsible for nutrient losses in the farm cycle. Currently, farm-specific ammonia emissions are calculated using the Kringloopwijzer model, which tends to over- or underestimate actual ammonia emissions. Therefore, the possibilities of a measurement-based approach are evaluated.

This study analyses the relationships within the feed-manure-AEP sequence. A comprehensive approach is used, involving 23 manure parameters and 12 feed management parameters. The most important predictors of the AEP include N, TAN, Norg, N90, and the C/N ratio, whilst urea in milk, pH, and DS showed low significance. Silage maize and VEM are identified as feed management parameters with a positive indirect relationship with the AEP, whereas other roughage and fresh grass exhibit a negative indirect relationship. The calculated TAN value plays a central role in the emission calculations of the Kringloopwijzer model. There are concerns about the accuracy of this value as well as the absence of other manure parameters in the calculation, highlighting the need for further research. Currently, it is uncertain whether the AEP measurements will be suitable for an emissions-based policy, due to the incapacity to directly represent actual ammonia emissions and the uncertainty regarding the interpretation of the results caused by the period prior to the measurements. Nonetheless, the measurements are valuable in assessing the influence of the manure composition on the AEP, and how it has been affected by feed management strategies.

Food loss and waste (FLW) generation is a global issue that has recently gained an increasing attention. It has previously been estimated that approximately one third of all food globally produced is wasted. Recently, other accounts have been made, for various food products and focusing on various geographical scopes, sometimes disaggregating between various qualities of FLW, but none was found to quantify FLW per quality at the global level. This would be a pertinent addition to the ongoing research, as the type of treatment (or valorisation) possible is dependent on the type of FLW, and this would be of great relevance in the global actions towards the achievement of the Sustainable Development Goal (SDG) 12.3 aiming at the reduction of food loss and food waste globally by halve by 2030. Additionally, recent literature focuses on avoidable FLW or does not separate between avoidable and unavoidable, although it is essential to address unavoidable FLW on its own as by its nature it cannot simply be prevented and its generation should thus be appropriately managed. Therefore, this thesis project aimed at answering how much food is currently being lost and wasted regarding fruits and vegetables at the global level and how it can be valorised. In the first part of the research, a Material Flow Analysis (MFA) was conducted at the global level to quantify unavoidable loss generated at the processing stage and unavoidable waste generated at the retail and consumption stages. The results show that the fruit value chain generates more unavoidable loss and waste than the vegetable value chain and that the retail and consumption stages generate more unavoidable waste than the processing stage of unavoidable loss. Additionally, regional hotspots were identified. In the second part of the research, an assessment of the valorisation pathways is conducted on the category of loss and waste streams identified as the most problematic by the MFA results, which was fruit and vegetable peel. The valorisation assessment was conducted following the concept of the FLW management hierarchy, which ranks the various end-of-life (EoL) treatments by prioritizing the most environmental-friendly and resource-efficient ones. In this study, the potential of fruit and vegetable peel loss and waste for reuse in food and feed, for the production of biobased materials, biofertilizers as well as biofuels was explored and quantified. The results suggest that an optimal FLW management system should be an adequate mix of various valorisation pathways. In regard to the SDG 12.3, efforts should aim on the one hand at preventing FLWthat can be avoided and on the other hand at valorising FLW that cannot be avoided.

One strategy to solve the severe environmental problems of Moroccan horticulture, especially water scarcity, is to upgrade agricultural methods by introducing high-tech greenhouses equipped with closed-loop hydroponic systems. However, these technologies are unprecedented in the country, and the implications for the environment remain unknown under local conditions.
Using life cycle assessment with a functional unit of one kilogram of tomatoes at greenhouse gate, this study aimed to predict the environmental impacts and the hotspots of two different closed-loop hydroponic systems if they were deployed in the Souss-Massa region, the biggest producer of the country. 18 mid-point indicators from ReCiPe were used, highlighting the most relevant ones for the region: use of net freshwater (UNFW), terrestrial ecotoxicity (TET), freshwater eutrophication (FE), and global warming (GW). A field trip to Agadir, the capital of the region, also helped to collect different views on the transition to these technologies.
The impact assessment revealed that artificial lighting would be the main contributor to 17 categories due to electricity being generated from oil and coal. To a lesser extent, landfilling of waste would also impact most of the categories. A new scenario with renewable energy showed that the impact from lighting can be drastically reduced by around 80% for GW, TET, and FE and by 34% in the case of UNFW. Contrarily, waste plastic recycling does not significantly influence the LCA results since the more abundant organic waste is a larger contributor.
For Souss-Massa to sustainably transit to hydroponic systems, it is essential that electricity consumption for lighting is drastically reduced and/or switched to clean sources. Organic waste needs to be revalorized by implementing composting processes or biodigesters. Lastly, the field trip exposed some key challenges to transit to more sustainable hydroponic farming systems: gaining the trust of farmers, finding financial support, and promoting collaboration between growers and the local community.

Offshore wind farms (OWF) are located in countries with densely populated coasts with numerous marine environment users, creating difficulties in organizing marine space. Fishing activities are among the most affected by offshore wind development (OWD). This situation is leading to problems and conflicts between stakeholders. In addition, spatial limitations such as exclusion zones are expected to be placed on numerous ongoing activities with increasing claims of competing uses.
The development of OWF involves multiple actors who are commonly organized in networks rather than a hierarchy, so cooperation between stakeholders is needed to find a better location for OWF and to minimize conflict among actors. Multi-use activities in OWD are a challenge and an opportunity to coordinate and agree among different actors in the future of offshore wind (OW).
Multi-use (MU) policies have yet to be developed enough, and they are in their first stages on the East Coast of the USA. Therefore, this thesis will analyze the perspectives, primary interests, and interdependences of the key stakeholders involved in OWD and how multi-use can be an integral part of the early stages of the permitting process to develop OW.
The thesis explores the integration of MU activities in OWD in RI, USA, and the benefits it can bring. The report uses actor models and comparative cognitive mapping (CCM) as a model to analyze stakeholder perspectives and identify potential conflicts and synergies in OWD.
Several strategies are suggested for addressing conflicts in OWD, including promoting collaboration and guidance that aligns with the goals of state agencies and other stakeholders, streamlining policies that support processes such as interconnection, grid integration of OWD, and permitting and policies. Moreover, it is essential to continue with assessments and research, engage the public and other stakeholders, and educate the general public about the benefits and risks associated with offshore wind energy (OWE) and the potential activities of MU.
Overall, the thesis emphasizes the importance of stakeholder collaboration and an integrated approach to governance and power distribution in addressing conflicts and promoting sustainable OWD in Rhode Island and the United States. These actions enable the sustainability and responsibility of this new industry operating in federal waters, enhancing coastal economies, minimizing conflicts, and maintaining ocean ecosystem services.
The findings of this thesis can aid in decision-making for issues in OWD and provide suggestions for developing new policies that can be integrated into the implementation of Marine Spatial Planning (MSP) for MU sites, allowing various users to utilize marine space sustainably.

The food system is strongly related to the pressure of our planetary boundaries, being responsible for a significant amount of greenhouse gas emissions, land use change, biodiversity loss, biochemical flows, and freshwater use. The dominant system in food production is monoculture, using agrochemicals and motorized equipment. However, monocultures are not the only way to produce food. Agroforestry can reach similar production levels but with environmental benefits such as enhancing biodiversity, reducing erosion, increasing soil carbon sequestration, and reducing agrochemicals pollution. Agroforestry also has a water saving potential, by reduction of runoff and improvement in water infiltration in the soil. The deep roots of trees can access deeper water and redistribute it to the upper layers. Additionally, the increase of shade in the system increases soil moisture and decreases soil evaporation and crop transpiration.

In the Maule Region, Chile, agriculture is strongly focused on fruit monocultures and is the region that consumes most of the fresh water in the country. The region has been affected by a prolonged drought, with an uninterrupted sequence of dry years since 2010. Climate projections estimate that it will get worse in the future, with an increase in temperature and a reduction in precipitation. To address this complex scenario of water scarcity in agriculture, a solution could be to move from conventional agriculture to agroforestry. This study seeks to answer the research question: What is the potential for water savings in the Maule watersheds, moving from conventional agriculture to agroforestry without affecting economic returns?

The study uses the agroforestry project "Huertas A Deo" (HAD) as a case study to analyze the productivity of the agroforestry system, calculate the water footprint, and perform economic and spatial analyses. The results show that the agroforestry system could be highly productive and have a lower water consumption per hectare compared to conventional monocultures. Also, it is economically competitive with the highest profit among the crops analyzed. The spatial analysis shows a five time reduction in the water footprint if all fruit monocultures are transformed to agroforestry. We conclude that the agroforestry system is a powerful tool to face water scarcity in the Maule region while still being competitive against monocultures.

Many higher-income countries export plastic waste to lower and middle-income countries where treatment facilities are often less advanced, which therefore comes with greater environmental consequences. China was the largest importer of plastic waste until it issued the Prohibition of Foreign Garbage Imports (referred to as "the China import ban") in 2017, which drastically changed global plastic waste trade. This study uses country-level data on waste management, and trade statistics combined with high resolution sub-national population density maps to assess the effect of the China import ban on plastic waste leakage into the aquatic environment. The results are presented on a 30-arc grid (approximately one km$^2$) resolution. Global mismanaged plastic waste (MPW) generation is estimated to increase from approximately 62 Mt (million ton) in 2016 to 64.7 Mt in 2019. Around 64\% is emitted into the aquatic environment, which is estimated to increase from approximately 39.5 Mt in 2016 to 41 Mt in 2019. MPW emission into the aquatic environment from imports accounted for approximately 1.9\% of global emission in 2016 and decreased to 1.4\% in 2019, which is the result of a 43\% reduction in global traded plastic waste. Despite the substantial decrease in Chinese aquatic MPW emission from imports, other lower or middle-income countries with higher rates of mismanagement and a higher probability of emission experienced strong increases.

Organic waste is the largest domestic waste category in the City of Buenos Aires (CABA) and is currently landfilled together with other waste streams. Landfilling organic waste not only has a large impact on the environment, but also leads to the loss of the value embedded in organic waste, such as nutrients and energy. In this regard, anaerobic digestion emerges as a potential waste treatment alternative that supports energy generation and nutrient recycling, while avoiding landfilling emissions.
Although AD is a relative mature and widely applied technology for the treatment of a variety of feedstocks (e.g., sewage sludge and animal manure), urban AD systems using biowaste are still in a preliminary stage. Therefore, the present research aims to evaluate the economic performance and the carbon footprint of this technology in CABA in the context of two case studies, where biogas is used to produce bioelectricity (C-1) and bio-CNG (C-2).
The case studies were assessed using a plant design which consisted of a biogas facility treating 23 thousand t/y of substrate, a mixture of OFMSW and recycled liquid fraction. Once biogas is produced as a result of the digestion process, a CHP and a membrane unit are used to produce bioelectricity and bio-CNG, respectively. Moreover, digestate, the material remaining after anaerobic digestion, is pasteurized for its utilization as biofertilizer on land.
The results of the economic analysis suggest that, under defined conditions, a positive NPV, IRR, and payback period can be obtained for both case studies. Nevertheless, there are high chances that the economic performance becomes negative, especially when changes are simulated that directly impact the amount of revenue the project makes.
The results of the carbon footprint indicate that both case studies could lead to substantial carbon savings, given that the avoided GHG emissions are substantially higher than the emitted ones. Large savings are obtained from avoiding the landfilling of organic waste, and replacing conventional energy, fuel, and fertilizers. The results of the carbon footprint are less sensitive to simulations performed, given the margin of avoided emissions over the emitted ones.
The analysis concluded that while both case studies are very likely to present environmental benefits, the economic constraints might impose a drawback for its implementation. Therefore, the support of the government is crucial to promote the adoption of AD, considering all the benefits that are associated with this technology.

Recovering phosphorus from manure allows to cycle a valuable nutrient back to agriculture while offering farmers a way to comply with the increasingly restrictive legislation concerning livestock manure application on agricultural land. To this end, a novel biocrystallization process in an Upflow Anaerobic Sludge Bed (UASB) reactor has been developed to recover phosphorus by retaining it in the sludge bed of the reactor, while producing biogas as a valuable by-product. Previous research has proven that this process is effective at recovering phosphorus at a lab level, but the economic feasibility and environmental performance of the process are still unknown. The present study analyses how this technology would perform from an environmental and economic perspective, to identify bottlenecks that could be addressed from the early stages of development.

The process was assessed using a conceptual design which consisted of an industrial facility treating the excreted manure of 11 farms in the region of Friesland, the Netherlands. The manure which was mechanically separated on-farm was later digested in the UASB reactor. The P-rich sludge obtained was dried to obtain a 2% P wt CaP fertilizer, while the effluent was stripped to later recover the ammonia as diammonium sulfate with a 7% wt N content.
The environmental assessment suggests that the P biocrystallization process could retain up to 41% of the initial P, while reducing the Global Warming Potential (GWP) associated with a conventional manure treatment by 36%. On the other hand, the techno-economic assessment, suggests that the P biocrystallization process could lead to a treatment cost of 26 € per ton of manure, which is nearly twice the value expected for a conventional manure treatment under the studied conditions. The elevated costs can be mainly linked to the high capital costs caused by the elevated energy requirement triggered by the drying unit needed to reduce the water content of the CaP fertilizer and by the high temperatures needed for the thermophilic digestion.

The analysis concluded that the P biocrystallization process is likely to present relevant environmental benefits when compared to conventional manure management systems, however, the economic constraints might impose a drawback for its implementation. Further research is suggested at a lab level to find methods to reduce the water content in the sludge and to study the effects of reducing the temperature of the anaerobic digestion (e.g., working at mesophilic conditions).

Cocoa production plays a significant role in global tree cover and biodiversity loss. Amid rising concerns over its role in environmental degradation, agroforestry has emerged as a potential solution to satisfy growing global demand for cocoa in a climate-smart and sustainable way. As a shade tolerant crop, there has been much discussion over the potential ecosystem service benefits that cocoa agroforestry can provide if adopted in degraded production areas. However, not much is known in the academic literature regarding the amount of cocoa agroforestry that currently exists globally. It is also unclear to what extent cocoa agroforestry can be scaled up to and what the potential scale of impact of such an endeavor would be in terms of carbon sequestration. This study aims to address these questions by developing a spatial model that uses georeferenced data on global cocoa production and percentage of tree cover in agricultural areas to estimate the presence and distribution of cocoa agroforestry globally. Using data from the MapSPAM project on the physical area of cocoa production, this study found that approximately 10-21% of global cocoa production areas were covered by cocoa agroforestry systems in 2010. By applying global average findings on cocoa agroforestry benefits from Niether et al. 2020 to global cocoa monoculture areas in 2010, this study found that scaling agroforestry would contribute to sequestering approximately 175 to 199 million tons of carbon. This study also found that scaled agroforestry adoption is likely to reduce cocoa production by about 1.2 to 1.3 million tons per year. Further research examining the carbon benefits and ecosystem services of agroforestry adoption at different regional levels is needed to improve estimates provided in this global assessment. Moreover, challenges in adopting agroforestry are likely to differ across the multiple cocoa producing regions. Further research is thus needed to highlight the environmental constraints and socio-economic bottlenecks that may limit the benefits of agroforestry adoption in each of these regions.

The unprecedented major scale and rapid rate of urban growth put an increasing pressure on natural resources for providing energy, materials, and food- and nutrition security. Likewise, an alarming major increase can be witnessed in the generation of food waste (FW) in urban areas. While megacities contribute to 6.7% of the global population, 12.6% of global waste disposal can be attributed to them1. 30 to 50% of produced food is never consumed, and FW constitutes 25 to 30% of municipal solid waste in high-income countries which is expected to grow 35% until 20252. One of these high-income, highly urbanized areas is the Amsterdam Metropolitan Area (AMA), where the related impacts of FW treatment create important environmental and socio-economic challenges that demand optimisation in terms of reduced environmental impacts and enhanced resource recovery. The AMA poses an interesting case study with high ambitions for a circular economy in relation to organic and biobased resources, yet a comprehensive regional strategy for circular and sustainable FW waste treatment remains uncomposed, while effective FW prevention does not emerge. Especially with regard to techniques that obtain more high-value, circular products as aimed for by the Dutch government. Only few studies investigate these high-value techniques, and more importantly lack to demonstrate the role of governance in the socio-technical transition that is required, and the impact it has on the main actors in the current system, as it requires a change from a systems perspective. Therefore, this research applies a two-dimensional nexus governance approach specific to the context of three high-value valorisation techniques in the AMA that use fermentation technologies for fatty acids production (i.e. Chaincraft for feed additives, Amsterdam Green Campus for food additives, and the FABULOUS-project for bioplastics). It investigates how these technologies could contribute to more circular and sustainable FW valorisation. This is respectively analysed by means of a socio-technical analysis and social network analysis, including a baseline study of available FW flows and an environmental assessment (EA) of the investigated technologies.

Forestation originated in the planting of forest plantations with timber-sourcing as a goal. The practice has since changed to include a much wider number of forest types and aims. In recent years, forestation efforts are increasingly focused on forest ecosystem generation. These forest ecosystems can have a wide variety of goals, including Climate Adaptation and Ecosystem-based Disaster Risk Reduction. Forest ecosystems can help in Disaster Risk Reduction in two ways; they can decrease exposure to disasters (for example through increasing soil stability and decreasing landslides) as well as increase community resilience (for example through diversifying the income of local communities). These forest ecosystems require a different project approach than forest plantations as they need to be sustained on a much longer time-scale and their success often depends on interaction with the surrounding communities. One part of the planning- and decision-making process of forestation projects is spatial analysis. Large scale spatial analysis used in the initial phases of forestation projects to identify suitable areas for forestation. Most current analyses focus on bio-physical factors for single tree species. However, forest ecosystems projects include a wider variety of species and social factors are crucial in their success. Therefore, this research aims to understand the possibility of using socio-economic factors as spatial indicators in the planning of forest ecosystem projects. In order to understand the possibility of using different indicators for forest ecosystem suitability analysis, a number of bio-physical and socio-economic indicators are compared to forestation success for existing forestation projects in Ethiopia. Forestation projects are assessed from 5 different organizations with a total of 12 projects and 67 forestation sites. A literature review is conducted to understand factors influencing forestation success. From all identified factors influencing forestation success, 11 indicators are chosen based on data availability and limiting overlap in effects. Despite its lack of representation of social and economic success, vegetation growth, using Normalized Difference Vegetation Index or NDVI is identified as the most reliable way to determine forestation success because of the availability of consistent data for all projects. The suitability indicators selected are: soil texture, drainage, pH of soil, minimum monthly rain, solar radiation, elevation, distance to closest road, population, GDP, land cover and district. The forestation sites show a minimal average increase in NDVI. However, it is also found that areas without forestation projects with similar environmental and social factors show an increase in NDVI as well. When the success indicators of the reference sites are compared to the increase in NDVI, we see that the suitability indicators do not show a significant relationship with the NDVI increase over active project years. The study shows the importance of standardized monitoring of forestation projects in order to gather not only bio-physical improvement but also social success, especially for projects with a social purpose. The use of satellite imagery to make forestation success assessments do not only give an incomplete understanding of the forestation project, the data availability in temporal and spatial scale and resolution limit the assessment. Additionally, the study shows the difficulty in comparing varying project types with different aims, timespans and sizes. More research is needed that includes a larger number of forestation projects that have similar goals, methods, timespan and sizes, as well as a standardized reporting of social and environmental success. This could be achieved by combining data from several similar countries and by working closely together with forestation organizations that have standardized monitoring of their projects on both social and environmental success.