Long-Term Evaluation of Remedial Technology Performance in the Laboratory: Multi-year Experimental Test Plan

An understanding of the long-term effectiveness of remediation technologies is central to sustainable environmental cleanup. Long-term experiments are valuable for reducing uncertainty and predicting remediation outcomes at scales required for regulatory compliance. However, these types of tests can be costly and challenging to interpret. Therefore, contaminated sites often rely on short-term laboratory experiments that may not account for the potentially significant effects of gradual, time- dependent processes governing contaminant retention, release, and species transformation. For example, short-term lab experiments (from months to a year) conducted with sediments from the unsaturated and saturated zones at the Hanford Site play an important role in initial evaluations of remediation technologies but cannot capture the full extent of time-dependent reactions, leaving uncertainties in field-scale deployment. Here, long-term testing will be conducted on select technologies based on their performance in short-term testing. The overall objective is to directly address the challenges described above by generating and analyzing data on long-term (2–10 years) efficacy of selected remediation technologies, integrating this understanding into models, and providing critical input for remediation planning, monitoring, and 5-year review cycles for field-implemented remedies. Specific objectives include: 1. Evaluating long-term efficiency of promising remedies under site-specific conditions. 2. Generating robust parameters for modeling, reducing uncertainty in predictive simulations. 3. Advancing integrated monitoring by combining geochemical and geophysical observations. 4. Informing field-scale implementation by incrementally advancing technologies, identifying failure mechanisms early, and prioritizing robust, cost-effective remedies. Through systematic evaluation of technologies in laboratory-scale column experiments, integrated monitoring, and modeling support, this pro. Authors: Emerson, Hilary P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]; Szecsody, James E. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]; Lawter, Amanda R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]; He, Xiaoliang (Bryan) [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000338351917); Qafoku, Nikolla P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)] (ORCID:0000000232585379). DOE Contract: AC05-76RL01830. Subjects: 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; Contamination; Remediation; geochemistry; groundwater