The N.C. Department of Environmental Quality (DEQ) issued notices of violation to the wastewater pre-treatment programs for the cities of Greensboro and Reidsville for recent 1,4 dioxane discharges that violated water quality standards and the conditions of their wastewater permits.
The Division of Water Resources (DWR) based the violations on data submitted in the facilities’ required monthly discharge monitoring reports. The data indicated that on August 7, Greensboro had a discharge of 957 micrograms per liter of 1,4 dioxane. On June 12, Reidsville had a discharge of 367 micrograms per liter of 1,4 dioxane.
Both discharges represent violations of the state water quality standard by not protecting downstream drinking water facilities at EPA’s health advisory level for drinking water. Further, the discharge violated the conditions of the NPDES wastewater permits because the entities did not report the discharge to state officials within 24 hours and failed to implement proper control of industrial discharge.
Weekly sampling for 1,4 dioxane at the Reidsville and Greensboro wastewater treatment plants was initiated in October, during a DEQ investigation into elevated levels of 1,4 dioxane and will continue as long as necessary.
As part of the overall management strategy for 1,4 dioxane in the Cape Fear River basin, DEQ will continue to develop a compliance schedule to reduce the treatment plant effluent levels below the EPA’s health advisory drinking water value of 35 micrograms per liter in the immediate term and below the human health criteria level for surface water of .35 micrograms per liter as soon as it is feasible.
At the same time, DEQ is also working to determine and assess the additional sources of 1,4 dioxane contribution in the basin beyond the dischargers, that may be causing contaminated groundwater to infiltrate into surface water.
EPA has identified 1,4 dioxane as a likely human carcinogen. 1,4 dioxane is a clear liquid that is highly miscible in water. It has historically been used as a solvent stabilizer and is currently used for a wide variety of industrial and manufacturing purposes.
Since 2014, DWR has been investigating and sampling for 1, 4 dioxane in the Cape Fear River Basin and actively working to prevent discharges. DWR identified target areas of concern, including areas downstream of the Reidsville and Greensboro wastewater treatment plants. The division has worked with those facilities to reduce and prevent discharges through several measures including requiring effluent monitoring and the submission of corrective action plans outlining steps to further reduce 1,4 dioxane in their discharge and encouraging industrial dischargers to use the Division of Environmental Assistance and Customer Services’ engineering consultants to evaluate pollution prevention options at the source. Additional information on the ongoing management strategy is available on the department’s emerging compounds page.
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