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Improving the microbial quality of agricultural water through filtration can benefit small farms globally. The incorporation of zero-valent iron (ZVI) into sand filters (ZVI–sand) has been effective in reducing E. coli, Listeria spp., and viruses from agricultural water. This study evaluated ZVI–sand filtration in reducing E. coli levels based on influent water type and the percentage of ZVI in sand filters. A ZVI–sand filter (50% ZVI/50% sand) significantly (p < 0.001) reduced E. coli levels in deionized water by more than 1.5 log CFU/mL compared to pond water over six separate trials, indicating that water type impacts E. coli removal. Overall reductions in E. coli in deionized water and pond water were 98.8 ± 1.7% and 63 ± 24.0% (mean ± standard deviation), respectively. Filters constructed from 50% ZVI/50% sand showed slightly more reduction in E. coli in pond water than filters made from a composition of 35% ZVI/65% sand; however, the difference was not statistically significant (p = 0.48). Principal component analysis identified that the turbidity and conductivity of influent water affected E. coli reductions in filtered water in this study. ZVI–sand filtration reduces Escherichia coli levels more effectively in waters that contain low turbidity values. 

Food, energy and water (FEW) systems are critically stressed worldwide. These challenges require transformative science, engineering and policy solutions. However, cross-cutting solutions can only arise through transdisciplinary training of our future science and policy leaders. The University of Maryland Global STEWARDS National Science Foundation Research Traineeship seeks to meet these needs. This study assessed a foundational component of the program: a novel, experiential course focused on transdisciplinary training and communication skills. We drew on data from the first two offerings of the course and utilized a mixed-method, multi-informant evaluation that included validated pre–post surveys, individual interviews and focus groups. Paired Mann–Whitney–Wilcoxon tests were used to compare pre- and post-means. After the course, students reported improvements in their ability to identify strengths and weaknesses of multiple FEW nexus disciplines; articulate interplays between FEW systems at multiple scales; explain to peers the most important aspects of their research; and collaborate with scientists outside their field. Students also reported improvements in their oral and written communication skills, along with their ability to critically review others’ work. Our findings demonstrate that this graduate course can serve as an effective model to develop transdisciplinary researchers and communicators through cutting edge, experiential curricular approaches.