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PFAS in “renewable natural gas:” a research proposal

At Newtown Creek Wastewater Resource Recovery Plant, New Yorkers’ biosolids are mixed with compost in heated digester eggs to produce methane. This methane is purified by National Grid and fed back into New York’s gas lines (NYC DEP “Data Reporting”).

PFAS is a class of “forever chemicals” that never break down and are extremely harmful to human health (EPA “Risks of PFAS”). Emerging research on landfills shows that PFAS in landfill waste leaches out via methane gas (Smallwood et al). According to EPA documentation, biosolids from wastewater treatment are incredibly high in PFAS (EPA “PFAS in Sewage Sludge”), and biosolids make up the vast majority of material input to the Newtown Creek organics (NYC DEP “Data Reporting”).

If PFAS can spread through landfill gas, is it spreading through our renewable natural gas system back into New Yorkers’ homes? National Grid lobbied the city to raise rates on New Yorkers to pay for building the renewable natural gas system, and has trumpeted it as a landmark policy towards reducing its carbon footprint. However, middling uptime levels reveal 86 million cubic feet of gas flared in the last year (NYC DEP “Data Reporting”), causing enormous air pollution in a neighborhood with a deep history of environmental injustice.

The renewable natural gas plan was marketed as reducing our carbon footprint, making gas greener, and building a circular economy for New York. At the time, the PFAS risk was not nearly as well understood. But today, the RNG system is producing just ~0.05% of NYC gas and polluting the local air while poisoning the compost as well. As we scale up renewable natural gas, we must investigate whether we are spreading it back into New Yorkers’ homes through this (dubious) system.

Research Questions

  • What are the levels of PFAS in biosolids at Newtown Creek? Lacking EPA guidance on sludge safety, we seek to measure & publish the levels in NYC to get a sense of baseline contamination.
  • Does PFAS accumulate indoors from contaminated gas? Especially in small NYC apartments, does burning gas laced with PFAS accumulate, exposing residents cyclically to increasing levels of these toxins?
  • Are PFAS levels different/higher in RNG vs ground-source gas? We plan to sample the flared gas at Newtown Creek versus flared ground-source gas elsewhere to test contamination levels.
  • As part of flaring/leaking, is PFAS exiting the Newtown Creek facility via air pollution? Not all the methane is flared or captured, and PFAS-laced methane could be harming residents nearby, perpetuating environmental injustice in a lower-income industrial area.

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Works Cited

EPA. “Our Current Understanding of the Human Health and Environmental Risks of PFAS | US EPA.” Environmental Protection Agency (EPA), 26 November 2024, https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas. Accessed 2 May 2025.
EPA. “Per- and Polyfluoroalkyl Substances (PFAS) in Sewage Sludge | US EPA.” Environmental Protection Agency (EPA), https://www.epa.gov/biosolids/and-polyfluoroalkyl-substances-pfas-sewage-sludge. Accessed 2 May 2025.
NYC DEP. “Assessment of New York City Natural Gas Market Fundamentals and Life Cycle Fuel Emissions.” New York City Mayor’s Office of Long-Term Planning and Sustainability, 31 July 2012, https://www.nyc.gov/assets/dep/downloads/pdf/air/nyc-combined-natural-gas-report.pdf.
NYC DEP. “Biogas-to-Grid Data Reporting.” NYC DEP, https://a826-web01.nyc.gov/BiogasReport.
Smallwood, Thomas. “Per- and polyfluoroalkyl substances (PFAS) distribution in landfill gas collection systems: leachate and gas condensate partitioning.” Journal of Hazardous Materials, vol. Volume 448, no. 15 April, 2023, https://www.sciencedirect.com/science/article/abs/pii/S030438942300208X.