It is possible to recover and maintain the value of urban solid waste (USW) through the implementation of circular economy practices in the waste management strategy. This can have social, economic and environmental benefits. One of the most noticeable benefits is the reduction landfilled USW. To achieve this it is necessary to, firstly, understand the nature and magnitude of the USW problem and, secondly, implement treatment techniques for the different types of USW; yet these must fit the local socio-economic context. This quantitative research takes as a study case the city of San Cristobal de las Casas (SCLC), which is a main tourist destination in the south-east of Mexico. The research is divided in three parts. In the first part the nature and magnitude of the USW problem are mapped; this includes a field study of the USW footprint cause by tourism. The second part is an evaluation of the treatment techniques, for types of waste that are identified in the study case, that can be applied in the city to recover value from USW and match the socio-economic context. The third part, is a circular business case where organic waste, the largest waste type in terms of mass, is treated with pyrolysis to produce charcoal briquettes; the intention of this product is to reduce the consumption of cooking char and firewood from illegal origin in the city. The results demonstrate that, using the approach found in this research, it is possible to obtain a significant economic return and, at the same time, social and environmental benefits from the USW in SCLC by using a circular economy approach. Furthermore, these circular solutions can significantly reduce the amount of landfilled USW.

Food waste is a global issue that causes various but significant global impacts, wasting millions of hectares of arable land, 0.75 to 1.25 trillion of cubic meter of water per year, and about 1.5% of the global energy production. In developed nations, food waste occurs mainly at the retail and consumer stage. By 2050, 80% of the global food consumption will take place within cities. Cities are also a key nexus of energy, water, and food flows. Amsterdam offers an interesting case study as the city does not have any comprehensive strategy to tackle the food waste produced within its boundaries. Yet, the city has shown ambitions in transforming itself into a sustainable metropolis with strong renewable energy and circular strategies. This study uses the Food-Energy-Water (FEW) Nexus approach, particularly suited to understand the interactions and interconnections between Amsterdam’s food flows and the energy and water systems. This study performs a Material Flow Analysis to quantify the different food waste (FW) flows and their origins. It finds that households are the main producers of food waste compared to FW-producing businesses in Amsterdam. Bread, dairy, vegetables, and fruits are the largest avoidable FW, while vegetable peels, fruits peels, coffee grounds, and potatoes peels constitute the bulk of unavoidable food waste. It then quantifies the embedded energy and water present within these food flows. Using the latest developments in the field of bio-based economy regarding food waste valorization, it provides an inventory of the potential technologies available to valorize Amsterdam’s FW. The study then quantifies the energy and water inputs of 12 of these food waste-valorizing technologies. This step confirms the large knowledge gap regarding the water and energy intensities of the latest bio-based technologies. The type and amount of recovered resources through these technologies are also quantified. In addition, this study provides a review of the current social and commercial initiatives based in Amsterdam tackling this issue of food waste. It offers a six-category qualitative framework to assess their food waste rescue potential. Then, a new food waste management and valorization framework is proposed, based on the Value Pyramid model from the bio-based economy, the Food Waste Management Hierarchy framework, and the FEW nexus insights developed in this study. This new framework enables to outline strategies for both Amsterdam’s avoidable and unavoidable food waste flows. It suggests anaerobic digestion, Black Soldier Fly bioconversion, and composting as potential FEW-efficient solutions for Amsterdam’s unavoidable FW. Last, Amsterdam’s FW stakeholders are analyzed through their importance, interests, and potential roles in a future FW scheme. It suggests that the municipality and AEB, Amsterdam’s Waste-to-Energy plant should be at the center of a future FW valorization scheme. Overall, this study combines the FEW nexus perspective and the bio-based economy approach to identify the best options to manage and valorize Amsterdam’s food waste.

Copper-based fungicides (CuFs) are used in vineyards and fruit-farms as a preventive form of pathogen control. These have a fungicidal impact against mildew infections (Plasmopara viticola) and other fungi that attack grapevines causing poor plant development, fruit rot, and ultimately, poor wine production. If applied annually in large quantities, copper pollutes both the vineyard soil and the surrounding freshwaters. This research combines a copper soil transport model within vineyard systems, a downy mildew germination model, and a copper dosage model with the ultimate aim of diminishing copper usage to concentrations as low as reasonably achievable while determining its environmental fate. The copper soil transport model is based on a solid-solution partitioning model, water balance model, and biotic ligand model. The downy mildew model is built according to a mechanistic model which separates the morphological development of mildew into discrete variables. The copper dosage model is built by combining a grapevine development model, a spray efficiency model, and a deposition efficiency model. Running the simulation from 2009 to 2018 for a vineyard in the Bordeaux Graves region, the model predicts that copper usage could have been reduced to 4.7 kgCu*ha-1 annually by only applying during mildew infection events and accounting for leaf area dependent spray deposition rates. Improving spray efficiency by 10% could further reduce copper demand to 3.9 kgCu*ha-1, below the new European limit of 4 kgCu*ha-1. Soil pH and organic matter adjustments most affected copper speciation, controlling biological uptake rates, soil matrix storage, and leaching rates; while varying the clay content did not present significant impacts.

Both human health and the environment are directly influenced by dietary patterns. The EAT-Lancet commission on Food, Planet, Health has proposed an optimal diet if humanity wants to sustainably feed itself in 2050. Their analysis assumes global trade remains as business as usual. However, locally sourcing food has often been claimed to be less environmentally taxing. This analysis aimed to answer to what extent countries can be self-sufficient in growing the EAT-Lancet diet, and what the impact on land use and reactive nitrogen input to soils would be. Results here show that although a surprisingly large number of countries would be likely to be self-sufficient and some large countries could see environmental benefits, the global reactive nitrogen input and land use would be pushed far outside of planetary boundaries if global food trade were to disappear. This is mainly due to increased livestock consumption and production inefficiencies in Africa and Asia. Ultimately, although the environmental benefits of local production are real in some regions, global trade contributes to an efficient and sustainable global food system.