Mobilizing contaminants for efficient extraction. Cosolvent flushing involves injecting a solvent mixture, such as water with alcohol, into an aquifer impacted with Non-Aqueous Phase Liquids (NAPLs) to solubilize and increase the mobility of the compounds. The solvent and the solubilized NAPL are then removed through extraction wells, and either treated on-site or disposed of off-site. The cosolvent mixture is typically injected up-gradient of the contaminated area and allowed to flow through the impacted area. The cosolvent with the mobilized contaminants is then extracted. A reverse gradient approach may also be used, which involves injecting at the down-gradient edge of impacts and then pumping the cosolvent solution from up-gradient wells.
Removal of Non-Aqueous Phase Liquids (NAPLs) such as spent degreasing solvents (TCE and TCA), dry cleaning solvents (PCE), heavy fuel oils, and coal tar/creosote, can be one of the most challenging processes in remedial programs. IRSL offers our clients extensive experience remediating NAPLs using a variety of cosolvents.
Cosolvents, such as alcohol, increase the solubility, and hence the mobility, of various chemical contaminants, including chlorinated solvents and petroleum hydrocarbons.
Cosolvents can promote contaminant removal by:
- Increasing the solubility of the contaminant in water, which improves the mass removal per pore volume.
- Increasing the bioactivity of the system by increasing the mass of readily available substrates.
- Aiding in the manipulation of the geochemical conditions of the subsurface in order to promote various geochemical breakdown reactions.
- Fill Materials
- Fluvial Deposits
- Fractured Carbonate Rock
- Fractured Shale
- Glacial Till
- Aromatic Volatile Organic Compounds
- Chlorinated Ethanes
- Chlorinated Ethenes
- Petroleum Hydrocarbons
- Polycyclic Aromatic Hydrocarbons