In November 2024, Kimley-Horn began the two-year PFAS research pilot to test and compare various treatment technologies on PFAS contaminated groundwater at the Wigwam Mutual Water Company’s main drinking water well. The 120-gpm alluvial well not only exceeded PFAS MCL, but also had poor water quality with hardness concentrations > 1,100 mg/L as CaC03, TDS > 1,920 mg/L, sulfate > 850 mg/L and chloride > 340 mg/L. These background water concentrations can negatively impact most adsorptive, anion exchange and membrane technologies. Wigwam did not want NF or RO due to concentrate disposal limitations.
Kimley-Horn partnered with entities such as Rockwell Automation (RA), Endress Hauser, PCL Construction, Harrington Plastics, Hayward Flow Control and Industrial Controls LLC just to name a few who donated over $400,000 of time, equipment and instrumentation to the research pilot trailer on the $300,000 grant. EPA provided of in-kind water quality analysis for the duration of the field testing.
The team leveraged a previously used Red Rocks Community College Research Trailer for a Bureau of Reclamation (BOR) funded Zero Liquid Discharge Cooling Tower Blowdown Research Project but modified the EC system to include submerged ceramic ultra-filters (SCUF). The Kimley Horn Team retrofitted the trailer to accommodate the new treatment trains and a full suite of instrumentation and automation donated by industry partners such as RA and Endress Hauser that resulted in robust flow control, data logging and trending.
The primary goal of this research project was to remove high concentrations of PFAS in challenging background water quality by piloting various technologies in parallel, including anion exchange (AIX) resins, granular activated carbon (GAC), surface modified clay and electro-coagulation (EC) + submerged ceramic ultra-filters (SCUF). Additional tests were performed to determine if the EC + SCUF system de-fluorinated the PFAS rendering the solids generated from the process non-hazardous. A secondary goal was to determine if any of the treatment trains would improver general water quality.
