On Wednesday, March 17, David Mays, associate professor of civil engineering, was the guest speaker at the at the Colorado Groundwater Association March meeting. His presentation, “Plume Spreading for Improved Groundwater Remediation,” was well-received by the group.
Groundwater, found in soils and aquifers, represents 99% of the world’s supply of liquid fresh water. It is therefore a crucial component of our water supply, especially in arid states like Colorado. Unfortunately, gravity means that pollution often finds its way into groundwater, necessitating the art, science, and multi-billion dollar business of groundwater remediation.
This talk will describe an ongoing study, using both computer simulations and laboratory experiments, designed to test the simple hypothesis that groundwater remediation can benefit from an engineered approach to promote plume stretching and folding. This work, funded by the National Science Foundation, represents a new approach to the hydraulics of groundwater remediation based on a key idea borrowed from chaos theory: That stretching and folding optimizes mixing in laminar flows.
The lack of turbulent mixing soils and aquifers makes it difficult to blend chemical additives, which is why the National Research Council has observed that groundwater remediation reactions are usually confined to a narrow interface zone between the injected additives and the contaminated groundwater. The goal if this work is to take the literature on fluid mechanics and turn it into an engineered sequence of injections and extractions at wells that, it is hoped, will provide a new paradigm for the hydraulics of groundwater remediation. Accordingly, this talk will provide a brief introduction to chaos theory, and then summarize computer simulations and laboratory experiments designed to demonstrate stretching and folding for plume spreading.
David Mays serves on the faculty of the Department of Civil Engineering at the University of Colorado Denver, located on the Auraria Campus downtown, where he teaches fluid mechanics, pipe network design, and three graduate courses on hydrology. His research program addresses fundamental challenges in groundwater remediation using tools borrowed from complex systems science, including chaos theory (i.e., stretching and folding) and colloid science (i.e., fractal dimensions of permeability-reducing deposits in aquifers). Applications of this research have included pervious concrete, aquifer storage and recovery, and hydrocarbon reservoir engineering. Since joining CU Denver in 2005, Dr. Mays has advised 17 graduate students and published 14 refereed papers and 5 book chapters. More information, including course materials, are available through his website (http://carbon.ucdenver.edu/~dmays).