PFAS drinking water standards are continuously evolving at state and Federal levels, propelled by an expanding body of toxicology data. At the same time, many states and the EPA have been advancing initiatives to reduce greenhouse gas (GHG) emissions. The primary treatment mechanism for PFAS in drinking water is granular activated carbon (GAC); GAC is produced from coal or high-temperature treatment of biomass and has a quantifiable, non-trivial GHG footprint. The project team conducted an evaluation, using the State of Maine as a model domain, that involved modeling and calculation of GHG footprint associated with removal of PFAS from drinking water. The overarching objectives of this evaluation include (a) ensuring that environmental footprint is not overlooked in state/Federal discussions on PFAS water treatment goals and (b) providing an initial framework through which such considerations may be applied in these discussions. The project team developed model calculations of GAC requirements to reduce six PFAS compounds to a range of target treatment concentrations. The life-cycle GHG footprint for GAC (calculated using a commercially available green-and-sustainable remediation tool and published data) included production, transportation, and recycling, as well as a treatment vessel. The model incorporated residential and municipal-scale treatment scenarios. Input parameters were developed based on these scenarios, and used to calculate per-user CO2 equivalent footprint (CEF) resulting from treatment of PFAS to drinking water target levels.
