Zimmerman, B., S. Smiley, B. Looney, and B. Cato.
2018 Long-Term Stewardship Conference, August 20-23, Grand Junction, Colorado. 17 slides, 2018

Although groundwater pump and treat was the originally selected remedy for the OU-1 area, the cleanup timeframe for the P&T remedy was projected to require substantially longer than the cleanup timeframe for cometabolic bioremediation. In 2014, DOE initiated a multi-year field demonstration to evaluate whether using edible oils to create "structured geochemical zones" and support passive natural attenuation processes for VOCs in soil and groundwater could expedite remediation of PCE and daughter products in the groundwater. Initially scheduled to operate for 3 years, impacts from an off-site dewatering operation and regional drought conditions during Year 2 caused perturbation in demonstration data trends, leading to extension of the project to include a fourth year. Nearing completion of the final year, results indicate the OU-1 groundwater system has recovered from the effects of the lowered groundwater levels and increased hydraulic gradients experienced in Year 2. Year 3 demonstration results indicate the dissolved-phase PCE and TCE plumes continue to decrease in size and mass. https://www.energy.gov/sites/prod/files/2018/10/f56/Zimmerman-Expediting-Groundwater-Remediation.pdf