Dr. Samuel Snow
Department of Civil & Environmental Engineering
Louisiana State University
Dissolved organic matter (DOM) in aquatic, marine, or engineered water treatment systems is known to play an important role in water treatment processes; membrane, chlorination, and UV dosing processes all account for the influence of DOM based on well-documented routes of interference. Yet the current DOM interference mechanisms do not apply to novel photochemical treatment technologies. Two systems will be discussed: UV-photocatalysis and the application UV LEDs for direct UV and for advanced oxidation processes at non-traditional wavelengths. First, the inhibition of TiO2-driven photooxidation processes is examined for three distinct fractions of organic matter collected from an operational membrane bioreactor treatment facility. Bulk DOM samples were taken at different times during the membrane operational cycle (i.e. immediately before or after chemical cleaning and mid-cycle) to assess the practical implications of membrane operation and fouling on photocatalytic processes. Second, the potential advantages and challenges of applying UV LEDs to water treatment processes are discussed. The new technology opens numerous opportunities, including novel advanced oxidation processes (AOPs) and the reduction of light attenuation by DOM by wavelength adjustments. These advantages may come at a cost, however, as recent studies have shown that the light may sensitize triplet-DOM, which can result in halogen radical (and possibly disinfection byproduct) formation. Finally, given my history at Tech, I will intertwine a few personal anecdotes of appreciation and encouragement to the faculty and current students.
Dr. Samuel Snow joined the faculty of the Department of Civil and Environmental Engineering at Louisiana State University as an assistant professor in August, 2016. Dr. Snow has a B.S. in Earth and Atmospheric Science and a Ph.D. in Environmental Engineering, both from the Georgia Institute of Technology. After graduation in 2014, he worked briefly at the Michigan Department of Environmental Quality, followed by an appointment as a Postdoctoral Research Associate in Michigan State University's Department of Civil and Environmental Engineering. His research interests include photochemical technologies, the role of sunlight in photochemical processes in natural systems, and interfacial and colloidal chemistry at the nano scale. Dr. Snow’s research group seeks to overcome challenges to practical photocatalysis by investigating the quenching of reactive oxygen species in photochemical treatment processes of natural or wastewaters. A second research theme involves the application of ultraviolet light emitting diodes to enhance existing and innovative treatment processes. A driving theme in Dr. Snow's research group is to approach the practical challenge of developing low-cost, sustainable, and robust water treatment systems by investigating the underlying science of the technologies.