Water, energy, and food are essential elements for human life, but face constant pressure resulting from economic development, climate change, and other global processes. Predictions of rapid economic growth, increasing population, and urbanization in the coming decades point to rapidly increasing demand for all three. In this context, improved management of the interactions among water, energy, and food requires an integrated “nexus” approach. This paper focuses on a specific nexus case: biogas generated from organic waste, a renewable source of energy created in livestock production, which can have water-quality impacts if waste enters water bodies. An innovative model is presented to make biogas and biomethane systems feasible, termed “biogas condominiums” (based on collective action given that small- and medium-scale farms on their own cannot afford the necessary investments). Based on the “farm to fuel” concept, animal waste and manure are converted into electrical and thermal energy, biofuel for transportation, and high-quality biofertilizer. This nexus approach provides multiple economic, environmental, and social benefits in both rural and urban areas, including reduction of ground and surface water pollution, decrease of fossil fuels dependence, and mitigation of greenhouse gases emissions, among others. The research finds that biogas condominiums create benefits for the whole biogas supply chain, which includes farmers, agroindustry, input providers, and local communities. The study estimated that biomethane potential in Brazil could substitute the country’s entire diesel and gasoline imports as well as 44% of the total diesel demand. In the United States, biomethane potential can meet 16% of diesel demand and significantly diversify the energy matrix.

O objetivo principal deste trabalho foi avaliar o estado geral da qualidade das águas do rio Belém a partir de duas abordagens complementares: o uso do Índice de Qualidade das Águas da National Sanitation Foundation e de protocolos perceptivos (Indicador de Intensidade Antrópica e Indicador de Valor de Habitat). Para o monitoramento, foram selecionados 10 pontos no seu canal principal além da foz dos 13 tributários principais. Os resultados do IQA nsf mostraram perda progressiva da qualidade das águas da nascente para a foz em razão do aporte de esgotos domésticos oriundos das regiões mais densamente habitadas próximas ao centro da cidade. A aplicação dos protocolos perceptivos mostrou maior variabilidade dos resultados, mas com tendência esperada em relação ao IQAnsf, indicando seu uso potencial como instrumento de avaliação complementar.

O objetivo principal deste trabalho é a análise da variação da relação entre a matéria orgânica carbonácea (representada pelas Demandas Biológica e Bioquímica de Oxigênio), Nitrogênio Total Kjeldhal e Fósforo Total nas águas de pequenos rios urbanos cujas áreas de drenagem apresentem baixa cobertura sanitária. Para isso, foram selecionadas 4 bacias hidrográficas urbanas com ocupação residencial, densidade populacional entre 0 e 100 hab/ha e similaridade de condições naturais e de ocupação humana. Os resultados mostraram alterações importantes nas relações entre os conteúdos de matéria orgânica carbonácea, Nitrogênio e Fósforo indicando que, a partir de uma condição natural não urbanizada, mesmo pequenas densidades populacionais são capazes de alterar significativamente a qualidade das águas.

Efforts to prioritize pharmaceutical products in urban rivers are still rare in Brazil. However, European and U.S. management experiences of pharmaceuticals in urban waters show that this has been one of the first steps necessary to reduce and control this type of pollution. The main objective of this research was to evaluate the presence of oral contraceptives in the catchment area of the Belém River in Curitiba based on the different criteria normally applied to prioritization. For this, in addition to a literature review, historical data on the concentrations of contraceptive hormones in the Belém River, data on pharmaceutical consumption in the basin (collected through interviews by random sampling in pharmacies and from the database of medicines provided by the City of Curitiba Health Units), and data from interviews conducted using intentional sampling with regional stakeholders. The results show that a consistent set of criteria supporting prioritization of ethinylestradiol and estradiol already exists, while the periodic monitoring of these two hormones has proved feasible and necessary in the waters of the region.