Abstract
A side effect of in situ groundwater remediation techniques that operate by establishing reducing conditions within an aquifer is that anoxic water exits these zones, posing a potential risk to aquatic organisms inhabiting areas of groundwater discharge downgradient from the site. A number of processes have been identified that can attenuate an anoxic plume in an unconfined aquifer with a fluctuating water table. The hypothesis that water table fluctuations increase oxygen transfer from air to water, through enhanced exchange from entrapped air, is tested in an intermediate-scale, fluctuating water table experiment. A dual-energy gamma radiation system was used to measure water saturations while dissolved oxygen (DO) concentrations were measured with flow-through oxygen microelectrodes. A hysteretic multifluid simulator was used to test whether the experimentally obtained water and entrapped air saturations, as well as DO concentrations, could be predicted using the assumptions of two-phase flow and equilibrium partitioning between the gas and the aqueous phases. The experimental results show that zones with entrapped air, formed during the imbibition portions of the experiment, were instrumental in re-oxygenation of the water. The fluctuating water table system also caused significant amounts of dissolved oxygen to be transported deeper into the flow cell. The simulator was able to predict water and entrapped air saturations, as well as dissolved oxygen concentrations reasonably well.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.