Superfund Research Program
Sequestration Processes for Attenuation and Treatment of Arsenic and other Toxic Elements in Mine Waters
Final Progress Reports
The presence of immiscible-liquid contamination is widely considered to be the single most limiting factor influencing the characterization and remediation of organic-contaminated hazardous waste sites. Thus, characterizing and remediating such sites is one of the most difficult problems in environmental hydrology. Therefore, Dr. Brusseau’s group has examined the complete dissolution behavior of chlorinated-solvent immiscible liquids trapped in porous media. Their results show that physical properties of the soil have a significant impact on the distribution of immiscible liquid within the soil, and thus on the dissolution behavior observed when water is flushed through contaminated media. This is especially critical for the final fraction of immiscible liquid remaining in the soil, which can become increasingly difficult to remove. The results indicate that simple models may not be able to accurately predict dissolution behavior, especially for more heterogeneous soil systems. Thus, they have developed mathematical models that incorporate non-ideal dissolution phenomena, allowing simulation of the observed behavior. These results provide a greater understanding of the dissolution process for immiscible liquids and will enhance the design and implementation of effective remediation systems. The results will also be pertinent to the issue of alternative, risk-based cleanup standards.