DOE Fellows Lecture Series featuring Dr. Miles Denham

FIU-ARC held the DOE Fellows lecture series on April 8, 2015 featuring Dr. Miles Denham from Savannah River National Laboratory (SRNL). Dr. Denham joined SRNL as a research geochemist after obtaining his Ph.D. from Texas A&M in 1992. He has been instrumental in developing innovative treatments for metals and radionuclides including mercury, uranium, strontium-90, technetium-99, and iodine-129. Dr. Denham has been the lead geochemist on several projects to transition active remediation systems (e.g., pump-and-treat) to more passive systems.

The title of Dr. Denham’s presentation was “Helping Nature Heal – Enhanced Attenuation.” Dr. Denham discussed the soil and groundwater challenges/limitations at the Savannah River Site (SRS), remedy selection criteria, active and passive remediation technologies and enhanced natural remediation. He talked about the various technologies that are being applied at SRS to remediate contaminants such as uranium, strontium and iodine. After the lecture series, Dr. Denham toured the ARC laboratories where ARC scientists and researchers showcased various ongoing research activities to support DOE-EM’s mission.

Dr. Miles Denham, at DOE Fellows Lecture Series

Dr. Miles Denham with ARC staff, DOE Fellows and students

FIU-ARC is supporting SRS by working in close collaboration with Drs. Miles Denham and Brian Looney on various environmental remediation activities.

• Study the effect of silicate injections to groundwater resulting in a pH increase leading to U(VI) sequestration, evaluate whether a base solution of dissolved silica can replace the previously used carbonate base and if silica solutions have enough alkalinity to restore the pH of the treatment zone.
• Evaluate if any synergy between U(VI) and humic acid will influence the behavior of U(VI).
• Monitor the U(VI) bioreduction after the ARCADIS demonstration at the F-Area, the in situ addition of a carbohydrate substrate to create reactive zones for metal and radionuclide remediation via the Enhanced Anaerobic Reductive Precipitation (EARP) process.
• Model the migration and distribution of humate injected into subsurface systems during deployment for in situ treatment of radionuclides, metals and organics.
• Model the surface water Tims Branch, development of a detailed GIS-based representation of the Tims Branch ecosystem and modeling of surface water and sediment transport in the Tims Branch system.
• Develop a sustainability plan for A/M Area groundwater remediation system, baseline analysis for identifying opportunities and evaluating options, energy efficiency, mechanical design and operations modifications for sustainable remediation (while controlling contaminant migration).

Dr. Denham also participated in DOE Fellow Hansell Gonzalez’s Ph.D. proposal defense titled “Unrefined Humic Substances as a Potential Low-Cost Remediation Method for Acidic Groundwater Contaminated with Uranium in Acidic Conditions.” Hansell Gonzalez participated in an internship at SRNL in summer 2014 under the mentorship of Miles Denham and studied the sorption and desorption of an unrefined humic substance onto SRS sediments. Hansell also studied the fraction of humic molecules sorbed on the sediment by studying the E₄/E₆ ratio and E_ET/E_BZ ratios. Based on his internship research, Hansell prepared a technical reported titled, “Study of an Unrefined Humate Solution as a Possible Remediation Method for Groundwater Contamination.

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