PFAS Updates

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What are PFAS?

Per- and Polyfluoroalkyl Substances (PFAS) are manufactured chemicals used in industrial and consumer products since the 1940s because of their useful properties. (They resist heat, oil, stains, grease, and water.) A common and concerning characteristic of PFAS is that they break down very slowly and can build up in people, animals, and the environment over time. As a result, they are often referred to as forever chemicals.

There are thousands of different PFAS, some more widely used and studied than others.

Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) are two of the most widely used and studied forever chemicals, and the two most commonly found in Greensboro’s watershed.

Common uses for PFAS include:

Coatings on food packaging, especially microwave popcorn bags and fast-food wrappers
Non-stick cookware
Components of fire-fighting foam
Industrial applications

Questions? Concerns? Contact Water Resources’ water quality laboratory at 336-373-7527 or by email.

How is Greensboro Removing PFAS Contaminants and Improving Your Drinking Water?

Greensboro's Water Resources Department has actively sought a solution to remove forever chemicals from drinking water after their 2014 discovery in Greensboro’s reservoirs and drinking water. Following the completion of a yearlong pilot testing initiative of multiple water treatment technology options in 2022, the City selected a Granular Activated Carbon (GAC) contactor system for the Mitchell Water Treatment Plant (MWTP) and Townsend Water Treatment Plant (TWTP).

The deep bed GAC contactors ensure the plants meets the Environmental Protection Agency's (EPA) National Primary Drinking Water Regulation (NPDWR) enforceable levels, called maximum contaminant levels (MCLs). The system, designed by a City team, reduces PFOS and PFOA (the PFAS with the highest levels in our source water) to a level below the EPA’s MCLs of 4 parts per trillion (ppt).

Learn more about the Major Mitchell Advanced Treatment Emerging Contaminates Project and Townsend Advanced Treatment Facility Project on Drinking Water Supply Treatment Projects webpage.

Major Mitchell Water Treatment Plant Improvements and Schedule

Major Mitchell Water Treatment Plant Improvements

Pump Station and GAC Treatment
New Operations/Maintenance Facility and Rehabilitation of Plant Laboratory/Control Room
Site Security Improvements - Extension of Property Boundary Exterior Brick Fencing
Electrical Service Improvements
Site Stormwater Improvements
Site Access Improvements – Battleground Avenue
Dual Media Treatment System
Relocation of Chemical Facilities
Reconfiguration of Flocculation and Sedimentation Basins
Installation of new Backwash Treatment Basin for residuals (solids) removal
Modifications of Existing Equalization Basin
New Backwash Transfer Pump Station
Clearwell and Other Drain Improvements

Mitchell Water Treatment Plant Improvements Schedule

June 2023	Issued a Request for Qualifications for the Construction Manager at Risk (CMAR) Team for the Mitchell Water Treatment Plant Improvements
January 2024	Re-Issued Request for Qualifications for the CMAR Team
September 2024	Re-issue a Request for Qualifications for the CMAR Team
September 2024	Treatment Plant Rezoning Meeting (City's Petition Response, Petition, Presentation, Recording, Summary, Handout, Project Story map, Impacted Neighborhoods Letter, Feedback Survey, Rezoning Process, Land Development Ordinance)
November 2024	Treatment Plant Rezoning Follow up Meeting (Presentation, Summary, Impacted Neighborhoods Follow up Letter)
February 2025	Council Approval of the first CMAR Contract
August 2025	Mitchell Water Treatment Plant Improvements Neighborhood Meeting (Presentation, Handout)
Spring 2026	Phase 1 Construction Begins
December 2026	Mitchell Water Treatment Plant Improvement Neighborhood Meeting (Presentation)
2026	Completion of the design of Advanced Treatment of Emerging Contaminants Project.
Fall 2026	Phase 2 Construction Begins
2031	Mitchell WTP Upgrades Project Completion and PFAS Regulatory Compliance Deadline

This schedule is likely to change based on regulatory requirements and deadlines.

FAQs

What is the Environmental Protection Agency's (EPA) final National Primary Drinking Water Regulation (NPDWR)?
In summary, the EPA finalized a NPDWR that establishes legally enforceable levels called Maximum Contaminant Levels (MCLs) for six PFAS in drinking water: PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. The EPA also finalized health-based, non-enforceable maximum contaminant level goals (MCLGs) for these PFAS.

One part-per-trillion (ppt) is equal to one nanogram-per-liter (ng/L).

Compound	Final MCLG (non-enforceable)	Final MCL (enforceable levels)
PFOA	Zero (0)	4.0 ppt
PFOS	Zero (0)	4.0 ppt
PFHxS	10 ppt	10 ppt
PFNA	10 ppt	10 ppt
HFPO-DA (i.e. GenX Chemicals)	10 ppt	10 ppt
Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS	1 (unitless) Hazard Index	1 (unitless) Hazard Index

Has Greensboro detected any of the six PFAS compounds listed in the NPDWR?
Yes. In 2014 the City initially detected PFOA and PFOS in amounts under the EPA’s 2009 Health Advisory Levels (HALs) of 200 parts-per-trillion (ppt) in Greensboro’s source water (Lake Higgins, Lake Brandt, and Lake Townsend).

Currently PFHxS can be present in levels above the MCL in the regulation.

The City’s contracted laboratory has not detected or detected values that well below the final MCLs or Hazard Index values for PFNA and HFPO-DA (i.e. GenX Chemicals).

View PFAS Sample Results
Non-Detected Contaminants list

Compound	Final MCLG (non-enforceable)	Final MCL (enforceable levels)	Detected in Greensboro above MCL
PFOA	Zero (0)	4.0 ppt	Yes
PFOS	Zero (0)	4.0 ppt	Yes
PFHxS	10 ppt	10 ppt	Yes
PFNA	10 ppt	10 ppt	No (<1.9/(ND)*)
HFPO-DA (i.e. GenX Chemicals)	10 ppt	10 ppt
Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS	1 (unitless) Hazard Index	1 (unitless) Hazard Index	No (<1.9/(ND)*) - PFNA and HFPO-DA Yes - PFBS

*These values are based on Eurofins Laboratory's Reporting Limit (RL). The RL (<1.9 ng/L) represents the lowest concentration of substance the equipment can reliably detect. Anything below the RL cannot be detected by the lab's testing equipment and may be defined as not detected (ND).

How is Greensboro removing PFAS from its source water?
During the City’s 2016-2019 Watershed Investigation, PFOA and PFOS were identified as the most present PFAS compounds found in the City’s source water and watershed. Lake Brandt had the highest levels. Since Lake Brandt provides water to the Mitchell WTP, Water Resources in 2018 installed a Powder Activated Carbon (PAC) system to reduce PFAS levels. Additional upgrades at the Mitchell WTP began to address needed rehabilitation and site improvements.
Water Resources determined a Granular Activated Carbon (GAC) contactor system was the best move forward. This system is specifically aimed at removing PFOA and PFOS from the city’s source water. The preliminary engineering is complete and final design will begin soon. A Construction Manager at Risk (CMAR) has been selected and construction and equipment procurement may start.
The entire project's estimated budget (including other facility improvements) is about $177 million. Details on the improvements and schedule can be found in the Major Mitchell Water Treatment Plant Improvements and Schedule in the previous section above. These improvements will be made within the five-year EPA compliance timeline. However, it is important to note this schedule may change based on regulatory requirements and deadlines.

Similar upgrades are planned for the Townsend WTP as part of the CIP budget for fiscal years 2027 to 2029. Although PFAS are present in Lake Townsend, they are at much lower levels than at the Mitchell WTP.

How effective is the Granular Activated Carbon (GAC) system?
Currently both Mitchell and Townsend WTPs have excellent filtering technologies that remove pathogens. However, traditional filtering systems are not designed to remove emerging contaminants such as PFAS.

Through a yearlong pilot study, the City investigated four types of PFAS treatment: high-pressure membranes, granular-activated carbon (GAC), ion-exchange resin, and novel sorbents. Based on the results of the pilot scale study, GAC was selected for full-scale treatment.

GAC is a very effective adsorption technology that removes the PFAS most present in the City’s water (PFOA and PFOS) and provides secondary water quality benefits such as additional taste, odor, and organics removal.

Activated carbon, such as GAC, is considered by the EPA and other professional organizations a best practice for PFAS treatment and is the most widely studied technology for PFAS removal. Other utilities, such as Cape Fear Public Utility Authority and the Town of Pittsboro, both located in North Carolina, are currently using GAC for PFAS treatment.

Over time, GAC media will become exhausted and must be periodically replaced to continue providing treatment. Once media can no longer remove PFAS at the required levels, it will be returned to the manufacturer and the PFAS will be removed. During the removal process media will be lost and replaced with fresh media. This process allows the City to reuse the media and potentially reduce operating costs.

Will my water service be interrupted during the improvements?
The City’s goal during construction is to avoid any water service interruptions by performing the work at night and through short plant shutdowns where water demand can be supplied by Townsend WTP or one of our four interconnections.

Will my water rates go up?
Many factors go into the setting of water and sewer rates. Three chief considerations Water Resources takes into account as it evaluates operational, maintenance, and capital improvement needs are ensuring regulatory compliance, addressing infrastructure deterioration, and supporting economic development. These factors, coupled with inflationary pressures, drive the need to seek City Council approval of utility rates. The planned improvements at the City’s water treatment plants to address forever chemicals coupled with other projects in our adopted capital improvement program will result in the department seeking modest rate increases over the next five years. By doing so we can ensure we have adequate funds to sustain our operations and meet the growing demands placed on our infrastructure for the benefit of our customers and community.

Health-related Information

EPA Final PFAS National Primary Drinking Water Regulation Summary

EPA Fact Sheet

EPA Frequently Asked Q&A

EPA Presentation Overview

EPA Monitoring and Reporting

EPA Ground Water and Drinking Water

EPA Health Advisories

EPA PFAS Community Engagement Panel Presentation

NC Department of Health and Human Services Presentation

State Health Related Resources

ATSDR- Perfluoroakyls