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preliminary feasibility study for PFAS-related water-quality concerns

preliminary feasibility study for PFAS-related water-quality concerns
client
City of Bemidji
location
Minnesota

helping address water-supply issues related to an emerging contaminan

When the Minnesota Department of Health (MDH) issued a health advisory due to the presence of per- and polyfluoroalkyl substances (PFAS) in the groundwater from municipal water supply wells in Bemidji, Minnesota, the city hired Barr to identify immediate, short-, and long-term response actions to keep their water supply in compliance. Bemidji’s wells are located downgradient of the Bemidji Regional Airport, where fire training was conducted with foam containing PFAS compounds.

Immediate actions included blending water from several wells to meet MDH guidance. Groundwater modeling was used to predict water-quality changes due to the new pumping scheme. We then put a plan in place that allows for rapid deployment of a temporary treatment system should a rise in PFAS concentrations occur. Planning included bench and pilot testing of three different types of treatment media and a layout of the piping needed to install the system.

Short-term planning included providing the city with PFAS-free redundancy in the water supply without committing to an expensive treatment plant. A new high-capacity well is being sited in an area not influenced by PFAS.

Long-term planning is currently underway, including an evaluation of the following options:

  • new-high capacity wells in other areas to reduce the risk of a single contamination event affecting all wells

  • treatment options for removing PFAS

  • treatment options for removing iron and manganese, which—if left in solution—fouls PFAS-treatment media

Barr is currently helping the city finalize the siting, design, and bidding of a new PFAS-free well that will meet regulatory guidelines while providing time for long-term planning with the regulatory landscape still in flux.