The US Army Corps of Engineers (USACE), Omaha District, has funded the design and construction of the treatment plant to treat groundwater from the city’s Borie well field. This vital groundwater supply was apparently contaminated with tricholorethene (TCE) in the late 1960s at the former F.E. Warren Atlas Missile Site 4, several miles southwest and up-gradient of the current Borie well field production wells.
The new facility was designed, constructed and placed into long-term automatic operations by Idaho-based firm McMillen, LLC and it decided that the most cost effective groundwater treatment choice was low profile air strippers. Air stripping is a simple and reliable technology for the removal of TCE from water supplies. The air stripping technology could be implemented into the city’s existing well field hydraulic profile at a location where re-pumping of the water was not required.
A total of four, 6-level tray QED E-Z Tray Air Strippers were used, each with a treatment capacity of 1,000 gpm, to ensure that the TCE treatment goal of less than 2 ppb could be reached without pretreatment. In this case, the E-Z Trays do not require off-gas treatment or sequestering agents, making the treatment process fairly simple. The turbulent mixing that occurs in the E-Z Tray units creates a high air to water ratio and large mass transfer surface area resulting in highly efficient contaminant removal.