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Nutrient rich wastewater containing emerging organic contaminants was used for struvite synthesis with a novel tandem process with a heterogeneous Fenton oxidation pretreatment. 

Simultaneous major nutrient nitrogen (N) and phosphorus (P) recovery from wastewater is key to achieving food–energy–water sustainable development. In this work, we elucidate the reaction kinetics, crystalline structure and chemical composition of the resulting solid precipitate obtained from simulated N and P containing wastewater solution using widely abundant low solubility magnesite (MgCO 3 ) particles in the presence of common transition metal ions, such as zinc (Zn 2+ ) or copper (Cu 2+ ). We show that up to 100 ppm Zn 2+ from the simulated wastewater can be incorporated into the struvite lattice as isolated distorted Zn 2+ while even at very low concentrations of ∼5 ppm Cu 2+ ions almost completely inhibit struvite crystal formation. The resulting solid precipitate distinctly affects soil microbial biomass carbon and soil dehydrogenase enzyme activity. These results show a cautionary case where abundant natural mineral MgCO 3 exhibits very different chemistry in Cu 2+ containing simulated wastewater and does not readily adsorb or retain NH 4 + and PO 4 3− ions, unlike less sustainable but more water-soluble magnesium sources, such as MgCl 2 , at the equivalent [Mg 2+ ] : [NH 4 + ] : [PO 4 3− ] molar ratio of 1.4 : 1 : 1. 

This paper examines the effect of having a third-party scientific expert present in stakeholder interviews. The study was conducted as part of a larger project on stakeholder engagement for natural resource management in the Verde Valley region of Arizona. We employed an experimental design, conducting stakeholder interviews both with and without an identified scientific expert present. Our sample consisted of 12 pairs of interviewees (24 total participants) who we matched based on their occupation, sex, and spatial proximity. For each pair, the scientific expert was present as a third party in one interview and absent in the other. We used a word-based coding strategy to code all interview responses for three known areas of sensitivity among the study population (risk, gatekeeping, and competence). We then performed both quantitative and qualitative analyses to compare responses across the two interview groups. We found that the presence of a scientific expert did not have a statistically significant effect on the mention of sensitive topics among stakeholders. However, our qualitative results show that the presence of a scientific expert had subtle influences on the ways that stakeholders discussed sensitive topics, particularly in placing emphasis on their own credibility and knowledge. Our findings indicate that researchers may be able to pursue collaborative, interdisciplinary research designs with multiple researchers present during interviews without concerns of strongly influencing data elicitation on sensitive topics. However, researchers should be cognizant of the subtle ways in which the presence of a third-party expert may influence the credibility claims and knowledge assertions made by respondents when a third-party expert is present during stakeholder interviews.