Aqueous-film-forming foam, containing per- and polyfluoroalkyl substances (PFAS), has long been used for fire-suppression training at the Bemidji airport. The PFAS have migrated into groundwater and are being captured by the city’s water-supply wells. In 2017, the Minnesota Department of Health (MDH) updated the health-based advisory values for two types of PFAS. The city asked Barr to evaluate its ability to provide drinking water that met the updated values. Barr recommended a multiphased approach including immediate, short-term, and long-term actions:
Continue monitoring the PFAS concentrations in the wells and implement an emergency water-supply plan if the concentrations exceed health-based guidance values.
Prepare a preliminary design for short-notice PFAS treatment of water from a portion of the city’s existing wells.
Perform bench and pilot testing that could be used to design an effective PFAS treatment system.
Evaluate and recommend a location for a new water-supply well.
Form a technical advisory committee consisting of representatives of the city, MDH, and Barr to find reasonable solutions to provide drinking water that meets MDH health-based advisory values.
The preliminary design for PFAS treatment of a portion of the city’s wells, as well as bench testing for granular-activated-carbon treatment and pilot testing for ion-exchange treatment, were completed in 2019. Evaluation of the location of the new water-supply well has also been completed and design is underway to install the new well and watermain to connect to the city’s distribution system.
Senior Environmental Engineer
Vice President Senior Civil Engineer