Based on a presentation by Kristine Williams, assistant director of water resources for the City of Greensboro

Discussions around the regulation and litigation of PFAS often mention water providers and we were fortunate to have Kristine Williams, assistant director of water resources for the City of Greensboro, provide an update on their PFAS Response.

Background on Greensboro’s Water Resources

The City of Greensboro has about 1,500 miles of water lines and about 1,500 miles of sewer lines. If laid end to end, that would cover a distance from here to Denver and back.

This fiscal year, the city is spending $221 million on capital infrastructure improvement, with a five-year total projected at $890 million. Rate increases between 8 and 10% per year for the next five years will be presented to City Council for approval to fund this capital plan, which covers three areas.

• 42% is focused on replacement and rehab of aging infrastructure
• 29% on regulatory compliance (including PFAS)
• 29% on expanding and increasing capacity of the system

Managing PFAS in the Water Supply

After finding PFOS at one of the city’s two water treatment plants, Greensboro began an investigation to determine the source. There are no point source dischargers above the city-owned lakes so they looked for firefighting activity and sampled longstanding industrial areas around the watershed.

While PFOS was concentrated around the airport area, the study found PFAS compounds everywhere it looked. The team learned there was a historical public safety fire training ground near the airport and fire-suppression systems in airport hangars. The airport area is in the watershed that feeds their Mitchell plant so they had found the primary source.

This means that there is no specific polluter to pay for the cleanup. Williams shared that even if there were, research is still being done to determine soil and groundwater remediation strategies for PFAS compounds. Their only solution is to remove it at the treatment plant.

Looking back on the history at this plant, the City of Greensboro began the testing in 2014, when the non-regulatory health advisory level (HAL) was set at 200. In 2016, EPA lowered the HAL to 70, which launched the described watershed investigation.

In 2018, the city installed a powder-activated carbon system as an interim treatment for levels approaching 70. Through a fate and transport, they created a model to monitor levels upstream to determine when levels might exceed 70 so they could have an early warning system and be proactive.

In 2020, the City of Greensboro began a pilot study to determine the best long-term treatment strategy. Williams notes that it was challenging to do that without knowing where regulators would set the limit. In 2022, EPA lowered the HAL to .02 parts per trillion. Williams commented, “We can’t even measure that low.”

As a result, the City of Greensboro set its target treatment to 4 ppt, which is now the established Maximum Contaminant Level (MCL). They must reach that level by 2029 and anticipate doing that through a granular activated carbon technology. Their project is under design with construction aimed to launch next year.

Currently, the city’s Mitchell plant ranges between 10 and 40 ppt and its Townsend plant ranges between 10 and 20 ppt. The estimated costs of PFAS treatment at those two plants, as well as Greensboro’s share of the Piedmont Triad Regional Water Authority’s current and expanded presence, sits at $235 million.

While the City of Greensboro expects to get some settlement funds, that will only fund less than 10% of those costs and they have been unsuccessful in securing state grants for the last two grant cycles.

Wastewater Considerations

The N.C. Department of Environmental Quality is working with wastewater plants to determine the contributions of PFAS compounds from industrial customers. The City of Greensboro asks for PFAS information in the industrial permit renewal process and is required to request a PFAS survey be completed by all new industrial users.

Based on preliminary information, in Greensboro, the drinking water may currently be the most substantial contributor to PFAS levels in the city’s wastewater plant. According to Williams, this means that eliminating it in drinking water will likely be the most effective way to reduce PFAS for downstream communities as well.

It is unknown how much PFAS comes from households and other domestic water uses.

“While we hear a lot about polluter pays, what if there isn’t a point source?” asked Williams.

If a numeric standard is established for PFAS in surface water, it is likely to create some additional ratepayer impacts. Williams said, “we along with our peers in the wastewater industry would like to see a minimization plan approach used, especially while we spend significant capital dollars on advanced treatment at our drinking water plants, so we can monitor to determine sources of PFAS and work to reduce them. We have successfully used this for 1,4-dioxane and reduced levels by 97% through collaboration with our industrial customers.” While she recognizes that a numeric standard may still be developed that could require treatment, Williams feels that the city has improved water quality in the interim.

The bottom line, according to Williams? “We all need safe drinking water. We need water and wastewater services to remain affordable for our customers as well as reasonable regulatory strategies. I believe we can have both.”