Officials will cut the ribbon Tuesday on a major water treatment plant at Pease International Tradeport.
The new system will scrub PFAS chemicals out of the large aquifer that once supplied drinking water at the former Air Force base.
A major supply well there was shut down in 2014 after high levels of likely harmful PFAS chemicals were found in the water.
Since then, the Air Force has spent nearly $58 million addressing the problem, caused by heavy military use of PFAS-based firefighting foam.
The new treatment systems pump water out of the polluted aquifers, cycle it through filters with a special resin to remove PFAS, then pump the cleaner water back into the ground.
This process will continue for years until the aquifer is clean. The PFAS-filled resin must be destroyed at an off-site hazardous materials incinerator.
The military says Pease is the first site in the country to use such technology.
A smaller version of the new system has been cleaning the Pease aquifer that supplies water to Newington since last year.