Featured Project
Evaluation of various ion exchange resins for determining uranium groundwater flux
Valerie Stucker
PhD Student, Department of Chemistry and Geochemistry
vstucker@mymail.mines.edu
Advisor: Dr. James Ranville
Other Colaborators: Mark Newman and Kirk Hatfield from University of Florida,
and Steven Cabaniss from the Univeristy of New Mexico
Abstract:
Rifle, CO is home to a former uranium and vanadium mill that is now managed by the Department
of Energy (DOE). The current remediation strategy employed is monitored natural attenuation;
however, acetate injections are being made to biostimulate microbes to reduce uranium from the
mobile, soluble form, U(VI), to insoluble U(IV). This work focuses on a novel technique to make
in situ measurements of uranium and groundwater fluxes using the passive flux meter (PFM). A
sorbent material with a resident tracer is encased in a screen material tube installed vertically
into predrilled wells at the contaminated site. The amount of contaminant sorbed and tracer
eluted can be used to calculate the contaminant flux which is essentially the product of the
contaminant concentration and the groundwater flow. Several ion exchange resins were tested
in lab scale batch experiments for adsorption/ desorption performance and efficiency in the
PFM using simulated and collected Rifle groundwater. Little dependence on aqueous uranium
speciation was seen with the resins chosen, but work is being conducted to evaluate current
modelling databases to better understand the uranium speciation at the site. Non toxic alcohols
were tested in bench scale flow box studies to understand elution properties and flow patterns
through the PFM. Initial field studies have been completed. Data has been collected to
determine uranium and groundwater fluxes with spatial and vertical profiles at the site as
well as data on the microbial communities at the wells of interest. This work can help DOE
to determine the effectiveness of biostimulation and relate flux variations to the variations
seen in the microbial biomass.
