By Peter Chawaga
As the prominence of perfluorinated chemicals (PFCs) in drinking water has risen, a range of treatment solutions have been employed around the country. In Arizona recently, this has meant the addition of carbon filtering and a multi-million dollar investment in new facilities to combat perfluoroalkyl sulfonate (PFAS).
“Tucson Water is installing new carbon filtering materials at its south-side treatment plan to remove more PFAS contaminants from drinking water,” Tucson.com reported. “The pollutants have become the subject of local and national concern [in 2018] as they’ve been discovered in drinking wells around the country, including in Tucson and Marana.”
Over the next nine years, Tucson Water plans to replace 56 tons of granular activated carbon (GAC) in use at one of its major treatment plants with a carbon that it believes to be more effective at treating PFAS. According to Tucson.com, the purchasing and installing the new carbon will cost about $600,000.
The move follows readings in monitoring wells of 30 parts per trillion (ppt) PFAS. Though lower than the U.S. EPA’s recommended health advisory of 70 ppt, that level is higher than some other standards indicate and higher than Tucson Water or local residents would like.
Meanwhile, the nearby town of Marana has secured a $15 million state loan to design and build two new treatment plants specifically to improve the contaminated water that more than one-third of its customers currently receive, according to a more recent report from Tucson.com. This water is contaminated with PFAS as well as 1,4-dioxane, an industrial solvent.
“The loan from the Water Infrastructure Finance Authority will provide Marana with money to start construction on schedule next August,” per Tucson.com. “The plants are scheduled to be finished and online by June 2020.”
According to the report, the loan was secured through a state revolving fund. As such, the federal government is providing 80 percent of the $15 million, while Arizona is providing the remaining 20 percent.
As the new treatment facilities are designed and built, Marana residents are relying on bottled water for drinking and some have installed reverse osmosis treatment systems to try and tackle the PFAS.
“Those systems aren’t effective at removing dioxane, however, removing 40 to 60 percent of it at most,” Tucson.com reported. “Town officials say that treating dioxane requires an aggressive, complex treatment process that can’t be done practically at home.”
As the threat of PFCs in drinking water continues to grab national headlines and raise concerns among treatment professionals and consumers alike, it seems reasonable that more locales around the country will pursue similar solutions to these recent efforts in Arizona.