College of Agriculture & Natural Resources│College of Engineering Department of Biosystems & Agricultural Engineering

Ryan Julien’s research focus has been pathogen risks arising from in-building plumbing. This includes quantitative microbial risk assessment (QMRA) for pathogens such as Legionella spp., identifying variables associated with elevated pathogen risks, and modeling in-building plumbing to assess hydraulic retention time. Ryan also has diverse work experiences, ranging from private consulting in oil and gas remediation to work in state government preparing air permits. As a Research Assistant II, Ryan is managing the logistics and data analysis of a wastewater sampling effort to monitor the prevalence of SARS-CoV-2, the causative agent of COVID19.

Publications

R. Julien, B. Saravi, A. P. Nejadhashemi, A. J. Whelton, T. G. Aw, and J. Mitchell*. “Identifying variables that most strongly influence Legionella concentrations in building plumbing” Environmental Science & Technology (under review)

C.J. Ley, C. Proctor, G. Singh, K. Ra, Y. Noh, T. Odimayomi, M. Salehi, R. Julien, J. Mitchell, A.P. Nejadhashemi, A.J. Whelton, T.G. Aw, Drinking water microbiology in a water-efficient building: stagnation, seasonality, and physicochemical effects on opportunistic pathogen and total bacteria proliferation, Environ. Sci. Water Res. Technol. 6 (2020) 2902–2913. https://doi.org/10.1039/D0EW00334D.

C. J. Ley, C. Proctor, K. Jordan, K. Ra, Y. Noh, T. Odimayomi, R. Julien, I. Kropp, J. Mitchell, A.P. Nejadhashemi, A. J. Whelton, T. Aw. Impacts of municipal water-rainwater source transitions on building plumbing and influence on microbial and chemical water quality dynamics at the tap. Environmental Science & Technology

Salehi, M., Odimayomi, T., Ra, K., Ley, C., Julien, R., Nejadhashemi, A.P., Hernandez-Suarez, J.S., Mitchell, J., Shah, A.D. and Whelton, A.3*. An investigation of spatial and temporal drinking water quality variation in green residential plumbing. Building and Environment, (2020) 169, p.106566.

Julien, R., Dreelin, E., Whelton, A. J., Lee, J., Gim, T., Kara, A., & Jade, D. (2020). Knowledge gaps and risks associated with premise plumbing drinking water quality. November 2019, 1–18. https://doi.org/10.1002/aws2.1177

Julien, R., Safferman, S. (2015) “Evaluation of food processing wastewater loading characteristics on metal mobilization within the soil.” Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering, 50(14):1-6