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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.

Participant interaction is said to be the hallmark of the focus group method, but a number of studies suggest that the defining feature of the method is virtually absent in most focus group research. Our meta-analysis of this debate over participant interaction in the focus group literature suggests that absence of interaction data reflects a philosophical position, rather than neglect. Participant interaction is treated differently in different types of research, reflecting a tacit division between researchers who view the participants primarily as individuals sharing held truths and those who view them as social beings co-constructing meaning while in the focus group. We question the habit of making assumptions about the 'proper' use of participant interaction and call for further reflection on its role and usage in light of the aim of each study. We argue that the treatment of participant interaction needs to be a conscious and explicit design decision -one clearly rooted in a theoretical perspective and best suited to the research purpose. While exploring this issue, we discuss how a researcher's lens affects how they deal with the interaction of participants, what they view as strengths and limitations of the method, and what kinds of results they end up with. We provide an overview of alternative approaches to participant interaction, offer strategies from different disciplines for analysing interaction, and propose a continuum of use demonstrating a range of options for when to use interaction.

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.

SummarySeveral studies have demonstrated that extensive formation of organically bound chlorine occurs both in soil and in decaying plant material. Previous studies suggest that enzymatic formation of reactive chlorine outside cells is a major source. However, the ecological role of microbial-induced extracellular chlorination processes remains unclear. In the present paper, we assess whether or not the literature supports the hypothesis that extracellular chlorination is involved in direct antagonism against competitors for the same resources. Our review shows that it is by no means rare that biotic processes create conditions that render biocidal concentrations of reactive chlorine compounds, which suggest that extracellular production of reactive chlorine may have an important role in antagonistic microbial interactions. To test the validity, we searched the UniprotPK database for microorganisms that are known to produce haloperoxidases. It appeared that many of the identified haloperoxidases from terrestrial environments are originating from organisms that are associated with living plants or decomposing plant material. The results of the in silico screening were supported by various field and laboratory studies on natural chlorination. Hence, the ability to produce reactive chlorine seems to be especially common in environments that are known for antibiotic-mediated competition for resources (interference competition). Yet, the ability to produce haloperoxidases is also recorded, for example, for plant endosymbionts and parasites, and there is little or no empirical evidence that suggests that these organisms are antagonistic.