The need for better nutrient management has spurred efforts towards more comprehensive recycling of nutrients contained in human excreta to agriculture. Research in this direction has intensified throughout the past years, continuously unfolding new knowledge and technologies. The present review aspires to provide a systematic synthesis of the field by providing an accessible overview of terminology, recovery pathways and treatment options, and products rendered by treatment. Our synthesis suggests that, rather than focusing on a specific recovery pathway or product and on a limited set of nutrients, there is scope for exploring how to maximize nutrient recovery by combining individual pathways and products and including a broader range of nutrients. To this end, finding ways to more effectively share and consolidate knowledge and information on recovery pathways and products would be beneficial. The present review aims to provide a template that aims to facilitate designing human excreta management for maximum nutrient recovery, and that can serve as foundation for organizing and categorizing information for more effective sharing and consolidation.

The focus group is a research methodology in which a small group of participants gathers to discuss a specified issue under the guidance of a moderator. The discussions are tape-recorded, transcribed and analysed. Notably, the interaction between focus group participants has seldom been evaluated, analysed or discussed in empirical research. We argue that considering the focus group in light of current research into interaction in problem-based learning (PBL) tutorial groups would facilitate the deliberate exploitation of group processes in designing focus groups, staging data collection and analysing and interpreting data. When the analytical focus shifts from mere content analysis to an analysis of what the participants themselves are trying to learn, one can explore not only what the participants are talking about, but also how they are trying to understand and conceptualise the issue under discussion.

For many in the Global North, urban life means that your shit is not your problem. We postulate that a possible reason for the global sanitation failure in urban areas is a disconnect between sanitation expectations—what we term the urban sanitation imaginary—and the practices required by proposed sanitation solutions. The case study presented here is based on interviews with residents of Villa Lamadrid, a marginalized neighborhood in Buenos Aires, Argentina, which faces significant public health impacts from an inadequate sewage management system. We solicited feedback regarding specific sanitation technologies frequently prescribed for poor urban communities—among them a urine diversion dry toilet with dehydration vaults. Even as this system is posited as ‘sustainable’ for the context of Villa Lamadrid in terms of ecological and economic factors, conversations with residents revealed why this option might not be sustainable in terms of social expectations. On the basis of interviews with community members we have defined four aspects of residents' urban sanitation imaginaries that we consider highly relevant for any consideration of sanitation solutions in this context: (1) an urban citizen does not engage physically or mentally with their shit or its management; (2) an appropriate urban sanitation system requires flushing; (3) systems that require user's engagement with their shit and its management signify rural, underdeveloped, and backward lifestyles; and (4) urban sanitation is a state responsibility, not a local one. Highlighting the urban sanitation imaginary methodologically and analytically goes beyond a discussion of culturally and contextually appropriate technologies. It examines linkages between user expectations and notions of urban citizenship and modernity. Ultimately it also draws attention to the sociopolitical dynamics and environmental justice issues embedded in discussions of sanitation and hygiene. While some of our results are specific to the Villa Lamadrid context, our research more generally suggests the need to consider sanitation imaginaries to reframe the discussion on sanitation interventions, particularly in underserved and impoverished urban areas.

There is an urgent need for innovation in the sanitation sector because the conventional model (toilet-to-sewer-to-treatment) is too time-consuming and costly, and alternatives are lacking. We estimate the challenge ahead by developing scenarios for 60 of the fastest-growing urban conglomerates in the World. We find that the majority would need to build out their sewer systems at a rate that is ten to 50 times higher than the highest rate for any project in the World Bank’s database, which is unrealistic. We also carry out a case study of Lagos, Nigeria, which suggests that, in any given year, 14–37% of Lagos State’s budget would need to be invested to provide sanitation to the presently underserviced population while keeping up with population growth, which also is unrealistic. Our study provides clear evidence that the conventional model for sanitation is unworkable for rapidly growing urban areas. We conclude there is an urgent need to encourage and fund projects that promote innovations that can tackle the three core challenges: can be built sufficiently quickly, are flexible, and affordable. This is not likely to happen unless the future generation is systematically trained and educated to creatively support innovation in sustainable sanitation.