Source Control vs. Plume Management
Water utilities with PFAS-contaminated source water have two fundamental strategic options: treat the water after it is extracted (pump-and-treat), or address PFAS at the source through soil washing or in situ treatment to reduce contaminant loading to groundwater. The relative effectiveness of these approaches affects long-term treatment costs and the residual PFAS burden reaching treatment plants.
Soil Washing for PFAS Source Areas
Soil washing techniques that use surfactant solutions, co-solvents, or cyclodextrin solutions to mobilize PFAS sorbed in contaminated soil have achieved moderate success in pilot applications. Removing PFAS from soil reduces the long-term loading to groundwater, potentially allowing pump-and-treat systems to achieve greater concentration reductions over time. However, soil washing is labor-intensive and generates PFAS-concentrated wash solutions requiring treatment.
In Situ Remediation Approaches
In situ technologies including colloidal activated carbon injection (ISCA), permeable reactive barriers, and in situ stabilization can reduce PFAS migration from source zones without excavation. Colloidal activated carbon achieves significant PFAS reduction in source zone groundwater by immobilizing PFAS on injected carbon particles, though the same chain-length limitations affecting conventional GAC apply to colloidal carbon as well.
Treatment Train Optimization
Source control measures that reduce PFAS loading to water treatment plant intake water can significantly improve activated carbon system performance by allowing longer carbon service life and fewer breakthrough events. Combined source control and treatment approaches often achieve better long-term outcomes than treatment alone for heavily contaminated aquifers