News & Events

Environmental Engrg seminar: Hexavalent chromium treatment: Coupling ion exchange & nanofiltration

Friday, March 09, 2018, 9:00AM - 10:00AM


Julie Korak

Bureau of Reclamation



A water sustainable future requires a diversified portfolio of drinking water sources with reliable, economical, and low energy water treatment processes. In arid climates, groundwater is an important water resource, but it is also more susceptible to natural or anthropogenic inorganic contaminants (e.g., salinity, nitrate, chromium, uranium, etc.). For rural communities with decentralized water systems, holistic water treatment processes are needed to not only deliver safe water but also to manage waste sustainably. This seminar presents a novel approach for hexavalent chromium removal by coupling strong base ion exchange with nanofiltration. Pilot-scale ion exchange studies conducted with water utilities in California and Oklahoma are presented, and different resin regeneration approaches are investigated to maximize trace metal recovery. In particular, the co-elution of sulfate and bicarbonate is found to have a strong impact on the recovery of vanadium and uranium. To minimize waste and recover excess regeneration salt, the waste brine is concentrated using nanofiltration, and an empirical batch concentration model is developed. Combined with the pilot-scale regeneration data, model simulations of the cyclical ion exchange process are used to evaluate regeneration efficiency, waste minimization and salt recovery. Looking ahead, this seminar argues that an integrated approach between lab experiments and model simulations will be instrumental in solving future water challenges.
Julie Korak is an Environmental Engineer in the Water Treatment Group at the Bureau of Reclamation (U.S. Department of the Interior). She received her Ph.D. in Civil Engineering from the University of Colorado Boulder and has B.S. degrees in both Chemical and Environmental Engineering. Julie is a licensed Professional Engineer in the State of Colorado and a National Science Foundation Graduate Research Fellow. Her research interests include developing holistic water treatment processes, integrating online sensors into water treatment operations, and characterizing natural organic matter in engineered systems. At Reclamation, she is currently supporting a large drinking water infrastructure project by evaluating the impact of dissolved metals in a mining-impacted watershed and the potential for corrosion in distribution systems due to source water changes.