Kootenai County tests reverse-osmosis pilot to treat landfill leachate; early results show tens of thousands of gallons reclaimed
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Summary
Kootenai County Solid Waste reported an operational reverse-osmosis/ultrafiltration pilot at the Fighting Creek landfill that has produced roughly 350,000 gallons of reclaimed water so far. County staff said they will continue testing before recommending permanent purchase.
Kootenai County Solid Waste staff reported Wednesday that a newly installed reverse-osmosis and ultrafiltration pilot system is operating at the Fighting Creek landfill and has produced roughly 350,000 gallons of treated (reclaimed) water since the pilot began.
The pilot was brought to the landfill after county staff learned local regional publicly owned treatment works would no longer accept untreated landfill leachate unless key constituents such as PFAS, PCBs and high total dissolved solids (TDS) were removed. "Leachate's considered an industrial wastewater, and it can be difficult to treat," JP said during the county's solid waste update. He said Jacobs Engineering and Dynatech (a New Jersey firm) were engaged to test and supply the system.
Why it matters: the county relies on local wastewater plants to accept treated leachate; losing that outlet required testing on-site treatment that can remove regulated constituents. County staff said success with the pilot would allow the landfill to continue discharging cleaned water to permitted treatment plants or otherwise manage leachate without overloading on-site storage.
What the county reported: Dynatech completed bench-scale treatability testing and delivered the ultrafiltration/reverse-osmosis unit in May 2025. JP said the ultrafiltration worked in May but the reverse-osmosis portion experienced a pump failure in early June; Dynatech credited the county one month of free rental while repairs were made. JP said the pilot is now running and "it currently appears successful. We're currently treating...28,000 gallons per day...14,000 gallons per day is actually coming back as pure clean water." He added the remainder is a concentrated solution that is being returned to the county's leachate pond for reprocessing.
Staff cautioned that the county will not recommend purchasing the equipment until the technology has been further proven. "The solid waste department will hold off on making any recommendation to purchase this equipment until the technology is able to completely prove itself," JP said. He said the department wants to process roughly 2,000,000 gallons (gross) through the pilot before making a purchase recommendation and is ramping the system up slowly to avoid fouling membranes.
Current handling and testing: JP said reclaimed water is being stored in a leachate pond that had been pressure-washed by Big Sky Industrial. The county will have samples tested (JP said "Harb's is gonna come take some tests") to confirm compatibility with local wastewater plants before truck-loading and delivering reclaimed water to a POTW for further confirmation.
Next steps and timelines: Dynatech has estimated the unit could process up to about 1,000,000 gallons per month gross and produce roughly 700,000 gallons per month of clean water once fully ramped. County staff said they are intentionally increasing throughput gradually while monitoring membrane performance and key analytes. No purchase decision has been made; staff will return with recommendation only after further operational data.
Sources: presentation to the Kootenai County Board of Commissioners solid waste update (Aug. 5, 2025).
