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Water Reclamation Manager

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Understanding Risk: What's Behind the Numbers

U.S. EPA 1,4-Dioxane Fact Sheet

EPA Safer Choice label

2019 Consumer Shopping Guide

Special Order by Consent (2021-2024)

1,4 Dioxane Updates

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Considerable progress has been made, and efforts to regulate industry have significantly reduced the average concentration of 1,4-dioxane in the effluent from the T.Z. Osborne Wastewater Treatment Plant (WWTP) by 97% since 2015.

The department continues to work proactively with local industries through the Industrial Pretreatment Program. Greensboro has a long and strong working relationship with NCDEQ and appreciates its guidance and assistance.

See Recent 1,4-Dioxane Sampling Results Here

Since 2014, 1,4-dioxane has been a topic of discussion and concern for state municipal wastewater dischargers and the NC Department of Environmental Quality (NCDEQ). Prior to this discussion, 1,4-dioxane was not regulated in treated effluent, and industries did not test for or monitor for it. 1,4-Dioxane is a synthetic chemical and by-product in products such as paint strippers, dyes, greases, antifreeze, aircraft deicing fluids, and some consumer products. It also exists as an unintended by-product in the manufacturing and recycling process of certain plastic and polyester products.

The North Carolina Department of Environmental Quality (NC DEQ) and the City completed negotiations for the issuance of a Special Order by Consent (SOC) in 2021 that addressed issues related to the discharge of elevated levels of 1,4-Dioxane from the T.Z. Osborne Wastewater Treatment Plant (WWTP) to South Buffalo Creek. The purpose of the SOC was to reduce the concentrations of 1,4-Dioxane discharged from the WWTP.

Learn more about what types of products may contain 1,4-Dioxane and how to avoid it in everyday household items:

Learn more:

Background

The T.Z. Osborne Water Reclamation Facility (TZO) is the City's wastewater treatment plant, rated to process 56 million gallons of wastewater daily. On average, 35 million gallons of sewage from homes and industries are treated to strict standards before being released into South Buffalo Creek. The TZO laboratory performs daily tests on wastewater, creek samples, and industrial discharges from multiple users of the City of Greensboro's wastewater system to ensure the quality of the treated effluent (discharged wastewater) released back into waterways.

Greensboro is located in the upper Cape Fear River Basin (the largest river basin in North Carolina). There are 13 Haw River/Cape Fear River drinking water intakes downstream of TZO, with Pittsboro being the closest at ~60 water miles below Greensboro and Cape Fear Public Utility Authority (CFPUA/Wilmington) and Brunswick County being the farthest downstream.

Why is the City targeting the source of 1,4-dioxane production?

The physical and chemical properties and behavior of 1,4-dioxane create challenges for its characterization and treatment. 1,4-Dioxane cannot be removed by conventional drinking water or wastewater treatment processes. 1,4-dioxane can be treated in drinking water, but a study shows that the cost estimate to treat it at wastewater facilities is not feasible due to the estimated cost of $40 million to $1.3 billion. The City’s wastewater plant, T.Z. Osborne Water Reclamation Facility, cannot treat these chemicals. In lieu of costly treatments that would increase utility bills, the City has reduced concentrations of 1,4-dioxane in wastewater through industry monitoring, removing sources of 1,4-dioxane instead. The technologies identified are commonly used in drinking water treatment, but not in wastewater treatment. An estimated $2-$3 million in pilot testing is needed to further refine cost estimates and determine which method will be most effective in reducing 1,4-dioxane from Greensboro’s wastewater.

History (2013 - 2024)

The Environmental Protection Agency (EPA) included 1,4-dioxane as one of 28 chemicals in the Drinking Water Unregulated Contaminant Monitoring Rule 3 (UCMR3) Study conducted from 2013-2015.

Due to detections downstream of TZO, the City first began an investigation into locating the source(s) of 1,4-dioxane within the City’s sewer collection and wastewater treatment facilities in March of 2015. By the end of 2015, a significant source had been identified, and the facility involved voluntarily initiated a source reduction program.

In 2021, the North Carolina Department of Environmental Quality (NC DEQ) and the City finalized a 24-month Special Order by Consent (SOC) to address elevated 1,4-Dioxane discharge from the TZO into South Buffalo Creek. The SOC aimed to ensure downstream water intakes stayed below the EPA's health advisory of 35 ug/l, later extended to 36 months with stricter limits.

*This page link contains all SOC data (2021-2024).

Extensive wastewater collection system trunkline sampling identified two significant industrial sources of 1,4-dioxane:

Centralized Waste Treatment (CWT) facility - Receives and treats non-hazardous wastewater from various industrial locations.
- After notification, immediately/voluntarily began lab analyses on all 300 clients, and turned away those with elevated values, resulting in significant financial loss.
- Long term voluntary actions included: research, bench testing, pilot testing, engineering, installation, and troubleshooting of a multi-million dollar proprietary pretreatment system to remove/reduce 1,4-dioxane discharge concentrations (start-up in 2021).

Organic chemical manufacturer – Manufactures certain polyethylene terephthalate (PET) products.
- The manufacture of Polyethylene terephthalate (PET)* products can inadvertently create 1,4-dioxane during processes that involve chemical reactions.
- In 2022, the company permanently ceased manufacture of these products at the Greensboro facility.

*PET plastic is a lightweight, strong, and recyclable material commonly used in beverage bottles and food packaging.

Commercial Businesses

Industrial Treatment (Industries)