A water treatment plant in Tucson is replacing more than 56 tons of activated carbon to address newly-discovered perfluorinated compound contamination from the nearby Superfund site.

“The fact that we have a treatment plant there at all is entirely driven by the Superfund site,” said Tim Thomure, director of Tucson Water.

The 10-square-mile Tucson International Airport site was designed as a Superfund in 1983. Superfund sites are considered some of the most contaminated places in the county.

The water treatment plant was set up 11 years later to address the groundwater contamination.

“The main process that we use is designed to remove TCE and 1,4 dioxane,” Thomure said.

But with the recent discovery of perfluorinated compound contamination, the plant decided updates were needed to have specific management of perfluorinated compounds and other carcinogenic contaminants.

“We’ve been managing those [perfluorinated] compounds with how we operate the facility,” Thomure said.

The plant set an internal goal of 18 part-per-trillion, well below the EPA standard of 70 part-per-trillion. Thomure said they were able to reach the goal with the current techniques.

“So this process is to essentially retrofit an existing part of our treatment plant to address an additional compound that it wasn't designed for,” he said.

Activated carbon efficiently removes TCE, 1,4 dioxane and perfluorinated compounds, so contaminant levels were within drinking water safety standards.

“While the water we’ve been delivering is safe … we’re essentially going the extra mile,” he said.

As with most Superfund sites, someone has to pay for the remediation up-front and then seek reimbursement through the EPA’s Superfund program and sometimes the legal system. Tucson Water anticipates the update will cost $600,000.

“We will be tracking our expenses and seeking reimbursement for it in the future as we identify who the responsible parties are for the presence of the perfluorinated compounds.”

The EPA identified nine groups, including the U.S. Air Force and the city of Tucson, as potentially responsible for the overall contamination. An estimated 25 groundwater contaminants have been identified at the Superfund site, and it takes time to investigate which party can be held responsible for each one.