Climate change and resource scarcity are putting increasing pressure on healthcare systems, making it essential to reduce the sector’s environmental impact. In Dutch hospitals, particularly Intensive Care Units (ICUs), large volumes of unused but contaminated medical consumables are routinely disposed of as a precaution against the transmission of infections. This linear, single-use approach generates significant waste and emissions, challenging long-term sustainability goals. This thesis investigates whether ultraviolet germicidal irradiation (UVGI), specifically using UV-C radiation, can serve as a sustainable alternative to the disposal of unused medical consumables in the ICU of the Leiden University Medical Centre. The research assesses both the applicability and sustainability of UV-C disinfection. Applicability was evaluated through an inventory analysis of ICU bedside carts and a workflow analysis comparing current practices with the implementation of UV-C disinfection. The sustainability was assessed using a Life Cycle Assessment (LCA) to compare the environmental impacts between UV-C disinfection and disposal.
A bedside cart inventory contains medical consumables of which approximately 75% are considered manufacturer-proven or literature-supported suitable for UV-C disinfection with a value of €323. The operational disinfection costs are €23 per bedside cart. Assuming 30-50% inventory levels combined with the patient data of 2023 and 2024 (22 and 33 bedside carts), the total avoided costs are estimated to be between €680-2,000 and €1,670-3,650 respectively, including capital expenditure. The disinfection time of a bedside cart including preparatory steps is estimated to be 65 minutes but may be shortened by, for instance, colour-coding the bedside cart compartments. No previous LCA study on UV-C disinfection of medical consumables had been conducted. The results indicate that UV-C disinfection as an infection prevention method has fewer environmental impacts compared to disposal. Across all assessed impact categories, including climate change, water use, and material use, reductions of 46% to 50% were observed.
Integrating UVGI within hospital settings can reduce environmental burdens and support circularity in healthcare supply chains. UV-C disinfection of medical consumables is best suited for hospitals with large ICU departments, as smaller ICU departments may not generate enough contaminated medical consumables to justify the investments, making financial factors critical to its feasibility. This study contributes to ongoing efforts within the Dutch Green Deal for Sustainable Healthcare and provides actionable insights for hospitals, UV-C device manufacturers, medical consumable manufacturers, and policymakers seeking to improve environmental performance in clinical settings.

World Bank data from 2023 indicates that 75% of the global population resides in middle-income countries, mostly in the Global South. Improved living standards in these regions have led to increased consumption and environmental impacts, including pollution, land use changes, and resource over-extraction. Colombia, known for its biodiversity, heavily relies on landfilling for waste management with low recycling rates. With a projected population of 57 million by 2050, sustainable waste management is crucial.

This study addresses the lack of research on community-led circular economy initiatives and women's roles in such projects in Colombia. Focusing on the "Guardianas del Manglar" (GdM) project on Colombia’s Pacific coast, it employs the Circular Value Flower (CVF) framework to analyze the values generated by the initiative. The GdM project, involving 133 women, collects approximately 4000 kg of waste per month, demonstrating environmental, economic, cultural, aesthetic, and social values.

The study's methodology includes semi-structured interviews and workshops, adapted to the contextual realities of Buenaventura. This approach highlights the importance of flexible, participatory research methodologies and the role of companies like Organización Carvajal in integrating informal waste pickers into the industrial sector. Despite challenges such as outdated waste management plans and social stigmatization, the study underscores the potential of community-led initiatives in fostering sustainable development in the Global South.

Harnessing wave energy from the world’s oceans provides an enormous chance to fulfil substantial parts of the energy transition’s demand for electricity from renewable sources. The technology that makes this possible is wave energy converters (WECs) - offshore structures that can convert the energy in waves into electricity. Although the energy conversion of this precommercial technology is not directly linked to greenhouse gas emissions like in other conventional power plants, environmental sustainability over the whole life cycle of the device needs to be ensured for a sustainable large-scale application. To assess this, in recent decades some Life Cycle Assessment (LCA) studies have been carried out on different WECs. However, there is still a gap in terms of number, quality, coverage of more sustainable design alternatives as well as impact assessment beyond greenhouse gas (GHG) emissions. Therefore, in this study a specific type of WEC – the point absorber – is assessed for its environmental sustainability by means of LCA. A parameterized cradle-to-grave LCA model of a single representative point absorber is implemented to assess the environmental impacts of a WEC, the influence of different hull materials, hotspots in impacts of WEC components as well as variations induced by different deployment locations. A GHG-intensity of 300-325gCO2eq./kWh with periphery and 52-77gCO2eq./kWh without periphery is found for a WEC deployed in the Dutch North Sea depending on the hull material. Using an alternative fibre reinforced concrete material for the hull can reduce impacts across all impact categories between 10% and 78%. Next to the structural materials in the WEC the electrical cable and vessel operations, especially for maintenance, were found to contribute significantly. This study showed that impacts of electricity from WECs have to decrease to reach the level of other renewable electricity generation technologies but revealed possible levers to achieve such a reduction.

This thesis studies the criticality of gallium, indium and silicon for a 1GWp production of III-V/silicon solar cells and assesses the environmental impacts and economic costs \& benefits of a recycling process for these solar cells. III-V/silicon is an emerging solar cell technology, that is expected to enter the market in between 2025 and 2035. It was found that gallium availability can become restrictive for large scale production of III-V/silicon cells, because the amount of high-purity gallium needed for an annual 1 GWp production of III-V/silicon cells (176.3 tons) is close to the entire 2019 world production of high-purity gallium (205 tons). It is therefore recommended to create additional high-purity refineries to refine low grade gallium to high-purity gallium. Moreover, in the long term, gallium can be recycled from end-of-life III-V/silicon cells. Various gallium recovery technologies from end-of-life products have been summed up from a literature review. One of them, an ethanol dilution process, is included in the flowchart of a recycling process for III-V/silicon solar panels. The environmental impacts of the recycling process are compared to the cradle-to-gate impacts of the production of the panels, by performing a life cycle assessment (LCA). The impact categories where the recycling process scores high are climate change, marine eutrophication, freshwater ecotoxicity, fossil resource depletion and ozone layer depletion. A suggestion to reduce the climate change impacts is to recycle the waste plastic that comes from the EoL panels, instead of incinerating this plastic. Finally a cost-benefit analysis (CBA) is performed. The CBA shows that recycling gallium, indium and silicon from 1GWp end-of-life III-V/silicon cells is likely to be profitable. With a product lifetime of 25 to 30 years, recycling is assumed to be profitable starting in the timeframe 2050-2065.

In May 2019 the Dutch permit system for nitrogen deposition was taken down for not abiding by EU legislation, which resulted in a large debate surrounding nature conservation. I researched the manner in which various newspapers portray this debate to their respective readers, in order to create a better understanding of the communicational field between sustainability sciences and the public. To do this, 160 articles from four national daily newspapers were analyzed for their usage of frames and portrayal of actors. The articles reflected no differences in usage of frames, however, actor portrayal varied significantly between newspapers: environmental experts appeared more often in De Volkskrant, there seemed to be a negative relationship between the number of portrayed farmers and construction workers, and, popular newspaper De Telegraaf showed more signs of partisanship than other newspapers. Conclusively, I made some suggestions to environmental researchers for future environmental debates.