CFPUA has begun more frequent water sampling after the City of Greensboro said high levels of 1,4-dioxane had been detected in discharge from the T.Z. Osborne Wastewater Treatment Plant.
Staff at Greensboro contacted CFPUA in the late afternoon Thursday, July 1, to say that 1,4-dioxane had been detected at approximately 615 parts per billion in discharge sampled Wednesday, June 30. The discharge flows to the Cape Fear River, where it would be expected to undergo significant dilution before reaching CFPUA’s intakes at Kings Bluff.
The Sweeney Plant, which treats water from the Cape Fear to produce drinking water for about 80 percent of CFPUA customers, is among the few facilities equipped to treat 1,4-dioxane. Ozonation and biological filters at Sweeney typically achieve about two-thirds removal of 1,4-dioxane from raw water during treatment.
CFPUA has long conducted regular monitoring for 1,4-dioxane, with test results published online. Beginning immediately, staff will be sampling raw and treated water daily to monitor concentrations of 1,4-dioxane. Test results typically take two weeks. CFPUA has requested a more urgent turnaround from its contract lab and expects results early next week.
A solvent stabilizer, 1,4-dioxane is considered by the U.S. Environmental Protection Agency to be a “likely human carcinogen.” Although 1,4-dioxane is not regulated, the EPA has established a drinking water concentration representing a 1-in-1 million cancer risk level for 1,4-dioxane of 0.35 parts per billion.