@article{jenny_jasper_simmons_shatalov_ducoste_2015, title={Heuristic optimization of a continuous flow point-of-use UV-LED disinfection reactor using computational fluid dynamics}, volume={83}, ISSN={0043-1354}, url={http://dx.doi.org/10.1016/j.watres.2015.06.031}, DOI={10.1016/j.watres.2015.06.031}, abstractNote={Alternative disinfection sources such as ultraviolet light (UV) are being pursued to inactivate pathogenic microorganisms such as Cryptosporidium and Giardia, while simultaneously reducing the risk of exposure to carcinogenic disinfection by-products (DBPs) in drinking water. UV-LEDs offer a UV disinfecting source that do not contain mercury, have the potential for long lifetimes, are robust, and have a high degree of design flexibility. However, the increased flexibility in design options will add a substantial level of complexity when developing a UV-LED reactor, particularly with regards to reactor shape, size, spatial orientation of light, and germicidal emission wavelength. Anticipating that LEDs are the future of UV disinfection, new methods are needed for designing such reactors. In this research study, the evaluation of a new design paradigm using a point-of-use UV-LED disinfection reactor has been performed. ModeFrontier, a numerical optimization platform, was coupled with COMSOL Multi-physics, a computational fluid dynamics (CFD) software package, to generate an optimized UV-LED continuous flow reactor. Three optimality conditions were considered: 1) single objective analysis minimizing input supply power while achieving at least (2.0) log10 inactivation of Escherichia coli ATCC 11229; and 2) two multi-objective analyses (one of which maximized the log10 inactivation of E. coli ATCC 11229 and minimized the supply power). All tests were completed at a flow rate of 109 mL/min and 92% UVT (measured at 254 nm). The numerical solution for the first objective was validated experimentally using biodosimetry. The optimal design predictions displayed good agreement with the experimental data and contained several non-intuitive features, particularly with the UV-LED spatial arrangement, where the lights were unevenly populated throughout the reactor. The optimal designs may not have been developed from experienced designers due to the increased degrees of freedom offered by using UV-LEDs. The results of this study revealed that the coupled optimization routine with CFD was effective at significantly decreasing the engineer's design decision space and finding a potentially near-optimal UV-LED reactor solution.}, journal={Water Research}, publisher={Elsevier BV}, author={Jenny, Richard M. and Jasper, Micah N. and Simmons, Otto D., III and Shatalov, Max and Ducoste, Joel J.}, year={2015}, month={Oct}, pages={310–318} }
 @article{jenny_simmons_shatalov_ducoste_2014, title={Modeling a continuous flow ultraviolet Light Emitting Diode reactor using computational fluid dynamics}, volume={116}, ISSN={["1873-4405"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84902352092&partnerID=MN8TOARS}, DOI={10.1016/j.ces.2014.05.020}, abstractNote={The use of ultraviolet (UV) light for water treatment disinfection has become increasingly popular due to its ability to inactivate chlorine-resistant microorganisms without the production of known disinfection by-products. Currently, mercury-based lamps are the most commonly used UV disinfection source; however, these lamps are toxic if broken during installation or by foreign object strike during normal operation. In addition, disposal of degraded, hazardous mercury lamps can be challenging in rural and developing countries for point-of-use (POU) drinking water disinfection applications. UV Light Emitting Diodes (LEDs) offer an alternative, non-toxic UV source that will provide design flexibility due to their small size, longer operating life, and fewer auxiliary electronics than traditional mercury-based lamps. Modeling of UV reactor performance has been a significant approach to the engineering of UV reactors in drinking water treatment. Yet, no research has been performed on the experimental and modeling of a continuous flow UV-LED reactor. A research study was performed to validate a numerical computational fluid dynamics (CFD) model of a continuous flow UV-LED water disinfection process. Reactor validation consisted of the following: (1) hydraulic analysis using tracer tests, (2) characterization of the average light distribution using chemical actinometry, and (3) microbial dose–response and inactivation using biodosimetry. Results showed good agreement between numerical simulations and experimental testing. Accuracy of fluid velocity profile increased as flow rate increased from 109 mL/min to 190 mL/min, whereas chemical actinometry saw better agreement at the low flow rate. Biodosimetry testing was compared only at the low flow rate and saw good agreement for log inactivation of bacteriophage Qβ and MS-2 at 92% and 80% UV transmittance (UVT). The results from this research can potentially be used for the design of alternative point-of-use drinking water disinfection reactors in developing countries using UV LEDs.}, journal={CHEMICAL ENGINEERING SCIENCE}, author={Jenny, Richard M. and Simmons, Otto D., III and Shatalov, Max and Ducoste, Joel J.}, year={2014}, month={Sep}, pages={524–535} }