(670f) Photolytic Inactivation of Cryptosporidium Parvum and Escherichia coli By Ultraviolet Radiation within a Microfluidic Reactor – Experimental and Modeling Development

Cryptosporidium spp. presents a persistent threat to human health, as one of the leading causes of waterborne illness [1]. Approximately 748,000 cases of Cryptosporidium infection, Cryptosporidiosis, occur in the United States annually with an estimated burden of $45.8M per year. Total medical costs for an outbreak can average $31.6M with a productivity loss of $64.6M, accruing to a total loss of ~$96M (approximated for an outbreak population of 403,000 based off the US Milwaukee outbreak in 1993) [2].

Cryptosporidium is a resilient protozoan parasite with a robust calcium shell. Standard chlorine disinfection techniques in water treatment are insufficient at rendering the waterborne pathogen inactive [3]. However, ultraviolet (UV) radiation treatment is effective at inducing molecular DNA damage [4]. The UV-induced inactivation pathway relies on the formation of lesions on DNA base pairs called dimers [3]. When a sufficient amount of these dimers are created, the replication process becomes inhibited causing deviations in transcription and replication leading to cell death [4].

This project harnesses the process intensification capabilities of microscale technology as an enhanced method for Cryptosporidium inactivation. UV treatment is performed within a microreactor to reduce transport lengths and control flow characteristics via microchannel geometry. Microscale chemical processes can be optimized through mathematical modeling and numerical simulation. The use of computational fluid dynamics joined with a robust understanding of the system and inactivation process allows for the extraction of pure kinetic parameters, decoupled from mass transfer effects. The data provided from the microscale reactor also provides insight into non-mass transfer limited reaction volumes. This experimental data is what ultimately leads to the extraction of kinetic parameters from the computational model. The model relies on fundamental principles of mass transfer, computational fluid dynamics, reaction kinetics and light attenuation. These parameters provide insight on kinetics occurring within the reactor, and more importantly within Cryptosporidium.

Cryptosporidium outbreaks can occur in a wide range of locations and circumstances. Our objective is to look for solutions beyond capital intensive centralized treatment plants. This can be achieved through the development of a water treatment unit that is more effective and energy efficient than current technology and in a form that allows for distributed, point-of-use application.

References:

[1] Painter, Julia E., et al. “Cryptosporidiosis Surveillance Report 2011-2012.” Surveillance Summaries, vol. 64, no. 3, 1 May 2015.

[2] Corso, Phaedra S., et al. “Cost of Illness in the 1993 Waterborne Cryptosporidium Outbreak, Milwaukee, Wisconsin.” Emerging Infectious Diseases, vol. 9, no. 4, 2003, p. 6.

[3] P. Gale, Risk assessment model for a waterborne outbreak of Cryptosporidiosis, Water Science and Technology, 41(2017), 1–7

[4] P.A. Rochelle, et al. Irreversible UV inactivation of Cryptosporidium Spp. despite the presence of UV repair genes1. The Journal of Eukaryotic Microbiology, 2004, 553–562

[5] This research is in part supported by the Advanced Technology and Manufacturing Institute (ATAMI) and managed by the School of Chemical, Biological and Environmental Engineering at Oregon State University. This research is also supported by Oregon State University Start-Up funds.