Source-separated human urine was collected from six public events to study the impact of urine processing and storage on bacterial community composition and viability. Illumina 16S rRNA gene sequencing revealed a complex community of bacteria in fresh urine that differed across collection events. Despite the harsh chemical conditions of stored urine (pH > 9 and total ammonia nitrogen > 4000 mg N/L), bacteria consistently grew to 5 ± 2 × 10 cells/mL. Storing hydrolyzed urine for any amount of time significantly reduced the number of operational taxonomic units (OTUs) to 130 ± 70, increased Pielou evenness to 0.60 ± 0.06, and produced communities dominated by Clostridiales and Lactobacillales. After 80 days of storage, all six urine samples from different starting materials converged to these characteristics. Urine pasteurization or struvite precipitation did not change the microbial community, even when pasteurized urine was stored for an additional 70 days. Pasteurization decreased metabolic activity by 50 ± 10% and additional storage after pasteurization did not lead to recovery of metabolic activity. Urine-derived fertilizers consistently contained 16S rRNA genes belonging to Tissierella, Erysipelothrix, Atopostipes, Bacteroides, and many Clostridiales OTUs; additional experiments must determine whether pathogenic species are present, responsible for observed metabolic activity, or regrow when applied.

Matrix-specific methods were developed and validated for the analysis of pharmaceuticals in human urine, struvite, soil, and vegetables.

This paper reports on social research investigating perceptions concerning the diversion of urine from the waste stream and its use as fertilizer in two study regions, New England and the Upper Mid­west. We hypothesized that discomfort or disgust might affect acceptance of such a shift in human “waste” management. However, our findings suggest that a more significant concern of those potentially involved in this process may be distrust of how economic interests influence scientific and technical information. Both physical risks (to the environment and public health) and socio-political risks (to fragile farm economies and consumer communities) play out at individual, household, regional, and global scales. We describe the intersection of these complex understandings as nested risks and responsibilities that must inform the future of urine reclamation. Our respondents' shared concern about environmental risks has already galvanized communities to take responsibility for implementing closed-loop alternatives to current agricul­tural inputs and waste management practices in their communities. Attention to these nested understandings of both risk and responsibility should shape research priorities and foster participatory approaches to urine nutrient reclamation, including strategies for education, planning, regulation, technology design, and agricultural application.