Tucson International Airport Area

Tucson International Airport Area

Superfund Site | Tucson Airport Remediation Project: Page 2 of 2

Action Taken

Groundwater remediation at the TARP project area began in 1994 when Tucson Water began to operate a remediation system consisting of a South Well Field of five extraction wells, a North Well Field of four extraction wells, and a groundwater treatment plant.  The TARP system treats groundwater at a rate of about 4,500 gallons per minute and provides hydraulic control and remediation of main plume of the TIAA Superfund Site regional aquifer. Since September 1994, the TARP system has pumped and treated approximately 47.7 billion gallons of groundwater and removed approximately 5,303 pounds (lbs.) of TCE from the regional aquifer. Clean water from the TARP treatment plant is delivered to the Tucson Water Department (Tucson Water) distribution system.

Status

TARP is in the operation and maintenance phase of cleanup. In 2013, Tucson Water constructed an Advanced Oxidation Process (AOP) system to remove TCE and 1,4-dioxane from the groundwater. The AOP treatment train includes ultra-violet light reactors, peroxide storage/feed equipment, and a granular activated carbon (GAC) tank for peroxide quenching. The AOP system began full operation in early 2014.

Water level and water quality data are used to evaluate the performance of the existing remediation well fields in achieving capture of the groundwater plume, and for remediating TCE and 1,4-dioxane in the aquifer. These data indicate that the TARP remediation system is meeting compliance requirements, and the TARP AOP treatment plant shows consistent performance in removal of VOCs and 1,4-dioxane. Tucson Water has also begun to plan for replacement of the extraction wells due to their deterioration since they were installed in 1994.

EPA plans to issue a Record of Decision (ROD) Amendment for the TARP project area by the end of 2017.  The ROD Amendment will formalize AOP as the treatment method to remove TCE and 1,4-dioxane at the TARP treatment plant.

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